Publications by authors named "Anand Joshi"

194 Publications

Self-reported Wheat Sensitivity in Irritable Bowel Syndrome and Healthy Subjects: Prevalence of Celiac Markers and Response to Wheat-free Diet.

J Neurogastroenterol Motil 2021 Oct;27(4):596-601

Department of Transfusion Medicine, P D Hinduja Hospital, Mumbai, India.

Background/aims: Most patients with irritable bowel syndrome (IBS) report food-related aggravation of symptoms. Wheat/gluten is one of the most commonly incriminated. We studied the prevalence of self-reported wheat sensitivity in patients with IBS and in a healthy population from a region in India consuming mixed-cereal diets, correlated it with serological and human leukocyte antigen (HLA) markers of celiac disease, and evaluated the response to a wheat-free diet.

Methods: We surveyed 204 patients with IBS and 400 healthy persons for self-reported wheat sensitivity. Testing for IgA anti-tissue transglutaminase and HLA DQ2 or DQ8 was done in individuals who reported wheat sensitivity. Consenting persons with wheat sensitivity were put on wheat-free diet and monitored for symptom change.

Results: Twenty-three of 204 patients with IBS (11.3%) and none of the healthy subjects self-reported wheat sensitivity. Of 23 patients, 14 (60.9%) were positive for HLA DQ2 or DQ8 and none for anti-tissue transglutaminase antibody. After 6 weeks on wheat-free diet, all 19 participating patients reported clinical improvement; fewer patients had bloating, diarrhea, constipation, and easy fatigue.

Conclusions: Eleven percent of patients with IBS self-reported wheat sensitivity. None of them had positive celiac serology; 60.9% were positive for HLA DQ2 and DQ8, suggesting a possible genetic basis. All of them improved symptomatically on a wheat-free diet.
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http://dx.doi.org/10.5056/jnm20086DOI Listing
October 2021

Effective connectivity differs between focal cortical dysplasia types I and II.

Epilepsia 2021 Sep 20. Epub 2021 Sep 20.

Charles Shor Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH, USA.

Objective: To determine whether brain connectivity differs between focal cortical dysplasia (FCD) types I and II.

Methods: We compared cortico-cortical evoked potentials (CCEPs) as measures of effective brain connectivity in 25 FCD patients with drug-resistant focal epilepsy who underwent intracranial evaluation with stereo-electroencephalography (SEEG). We analyzed the amplitude and latency of CCEP responses following ictal-onset single-pulse electrical stimulation (iSPES).

Results: In comparison to FCD type II, patients with type I demonstrated significantly larger responses in the electrodes near the ictal-onset zone (<50 mm). These findings persisted when controlling for the location of the epileptogenic zone, as noted in patients with temporal lobe epilepsies, as well as controlling for seizure type, as noted in patients with focal to bilateral tonic-clonic seizures (FBTCS). In type II, the root mean square (RMS) of CCEP responses dropped substantially from the early segment (10-60 ms) to the middle and late segments (60-600 ms). The middle and late CCEP latency segments showed the largest differences between FCD types I and II.

Significance: Focal cortical dysplasia type I may have a greater degree of cortical hyperexcitability as compared with FCD type II. In addition, FCD type II displays a more restrictive area of hyperexcitability in both temporal and spatial domains. In patients with FBTCS and type I FCD, the increased amplitudes of RMS in the middle and late CCEP periods appear consistent with the cortico-thalamo-cortical network involvement of FBTCS. The notable differences in degree and extent of hyperexcitability may contribute to the different postsurgical seizure outcomes noted between these two pathological substrates.
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http://dx.doi.org/10.1111/epi.17064DOI Listing
September 2021

Quantification of kappa opioid receptor ligand potency, efficacy and desensitization using a real-time membrane potential assay.

Biomed Pharmacother 2021 Nov 15;143:112173. Epub 2021 Sep 15.

Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, NE, USA.

We explored the utility of the real-time FLIPR Membrane Potential (FMP) assay as a method to assess kappa opioid receptor (KOR)-induced hyperpolarization. The FMP Blue dye was used to measure fluorescent signals reflecting changes in membrane potential in KOR expressing CHO (CHO-KOR) cells. Treatment of CHO-KOR cells with kappa agonists U50,488 or dynorphin [Dyn (1-13)NH] produced rapid and concentration-dependent decreases in FMP Blue fluorescence reflecting membrane hyperpolarization. Both the nonselective opioid antagonist naloxone and the κ-selective antagonists nor-binaltorphimine (nor-BNI) and zyklophin produced rightward shifts in the U50,488 concentration-response curves, consistent with competitive antagonism of the KOR mediated response. The decrease in fluorescent emission produced by U50,488 was blocked by overnight pertussis toxin pretreatment, indicating the requirement for PTX-sensitive G proteins in the KOR mediated response. We directly compared the potency of U50,488 and Dyn (1-13)NH in the FMP and [S]GTPγS binding assays, and found that both were approximately 10 times more potent in the cellular fluorescence assay. The maximum responses of both U50,488 and Dyn (1-13)NH declined following repeated additions, reflecting receptor desensitization. We assessed the efficacy and potency of structurally distinct KOR small molecule and peptide ligands. The FMP assay reliably detected both partial agonists and stereoselectivity. Using KOR-selective peptides with varying efficacies, we found that the FMP assay allowed high throughput quantification of peptide efficacy. These data demonstrate that the FMP assay is a sensitive method for assessing κ-opioid receptor induced hyperpolarization, and represents a useful approach for quantification of potency, efficacy and desensitization of KOR ligands.
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http://dx.doi.org/10.1016/j.biopha.2021.112173DOI Listing
November 2021

Clinical and electromyographic evaluation of botulinum toxin type A in the treatment of gummy smile: A prospective clinical study.

J Dent Res Dent Clin Dent Prospects 2021 5;15(2):122-128. Epub 2021 May 5.

Department of Oral and Maxillofacial Surgery, Saraswati-Dhanwantari Dental College and Hospital, Maharashtra, India.

The present study aimed to assess the effect of botulinum toxin type A (BTX-A) for the management of gummy smile and evaluate its stability after administrating BTX-A clinically and using electromyography. The investigators designed and implemented a prospective clinical study on 10 patients with a gummy smile. Patients with different types of gummy smile were injected with BTX-A in the levator muscles of the upper lip and were followed for six months. The effect of BTX-A was evaluated clinically and using electromyography preoperatively and after two weeks and three and six months. Statistical analyses were carried out using repeated measures ANOVA and post hoc Bonferroni tests for pairwise comparisons. The sample consisted of 10 patients with an anterior gummy smile (n=3), posterior gummy smile (n=2), mixed gummy smile (n=3), and asymmetrical gummy smile (n=2). There were significant differences ( < 0.001) between the mean gingival display and compound muscle action potential at two-weeks and three-month follow-ups. The maximum result was obtained at the two-week interval. The mean gingival display and C-MAP values increased slightly at the three-month postoperative interval and gradually increased to the baseline values at six-month follow-up. BTX-A is an effective, minimally invasive, and temporary treatment modality for gummy smiles. The electromyographic study is a convenient method for assessing changes in the upper lip muscle contractility to quantify the effect of BTX-A in the treatment of gummy smile.
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http://dx.doi.org/10.34172/joddd.2021.021DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8346717PMC
May 2021

Quantile Regression for Uncertainty Estimation in VAEs with Applications to Brain Lesion Detection.

Inf Process Med Imaging 2021 14;12729:689-700. Epub 2021 Jun 14.

University of Southern California, Los Angeles, USA.

The Variational AutoEncoder (VAE) has become one of the most popular models for anomaly detection in applications such as lesion detection in medical images. The VAE is a generative graphical model that is used to learn the data distribution from samples and then generate new samples from this distribution. By training on normal samples, the VAE can be used to detect inputs that deviate from this learned distribution. The VAE models the output as a conditionally independent Gaussian characterized by means and variances for each output dimension. VAEs can therefore use reconstruction probability instead of reconstruction error for anomaly detection. Unfortunately, joint optimization of both mean and variance in the VAE leads to the well-known problem of shrinkage or underestimation of variance. We describe an alternative VAE model, Quantile-Regression VAE (QR-VAE), that avoids this variance shrinkage problem by estimating conditional quantiles for the given input image. Using the estimated quantiles, we compute the conditional mean and variance for input images under the Gaussian model. We then compute reconstruction probability using this model as a principled approach to outlier or anomaly detection. We also show how our approach can be used for heterogeneous thresholding of images for detecting lesions in brain images.
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http://dx.doi.org/10.1007/978-3-030-78191-0_53DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8321392PMC
June 2021

Validation of semi-automated anatomically labeled SEEG contacts in a brain atlas for mapping connectivity in focal epilepsy.

Epilepsia Open 2021 Sep 15;6(3):493-503. Epub 2021 May 15.

Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH, USA.

Objective: Stereotactic electroencephalography (SEEG) has been widely used to explore the epileptic network and localize the epileptic zone in patients with medically intractable epilepsy. Accurate anatomical labeling of SEEG electrode contacts is critically important for correctly interpreting epileptic activity. We present a method for automatically assigning anatomical labels to SEEG electrode contacts using a 3D-segmented cortex and coregistered postoperative CT images.

Method: Stereotactic electroencephalography electrode contacts were spatially localized relative to the brain volume using a standard clinical procedure. Each contact was then assigned an anatomical label by clinical epilepsy fellows. Separately, each contact was automatically labeled by coregistering the subject's MRI to the USCBrain atlas using the BrainSuite software and assigning labels from the atlas based on contact locations. The results of both labeling methods were then compared, and a subsequent vetting of the anatomical labels was performed by expert review.

Results: Anatomical labeling agreement between the two methods for over 17 000 SEEG contacts was 82%. This agreement was consistent in patients with and without previous surgery (P = .852). Expert review of contacts in disagreement between the two methods resulted in agreement with the atlas based over manual labels in 48% of cases, agreement with manual over atlas-based labels in 36% of cases, and disagreement with both methods in 16% of cases. Labels deemed incorrect by the expert review were then categorized as either in a region directly adjacent to the correct label or as a gross error, revealing a lower likelihood of gross error from the automated method.

Significance: The method for semi-automated atlas-based anatomical labeling we describe here demonstrates potential to assist clinical workflow by reducing both analysis time and the likelihood of gross anatomical error. Additionally, it provides a convenient means of intersubject analysis by standardizing the anatomical labels applied to SEEG contact locations across subjects.
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http://dx.doi.org/10.1002/epi4.12499DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8408609PMC
September 2021

The Covid-19 pandemic in low- and middle-income countries, who carries the burden? Review of mass media and publications from six countries.

Pathog Glob Health 2021 05 4;115(3):178-187. Epub 2021 Mar 4.

Faculty of Medicine, Albert-Ludwigs-University Freiburg, Centre for Medicine and Society, Freiburg, Germany.

During the Covid-19 pandemic, rich countries employed lockdown and physical distancing policies for transmission control. However, the question still remains whether these measures are also suitable in countries with a fragile economy, which rests mainly on the informal sector. The impacts of lockdown measures in disadvantaged population strata in six low- and middle-income countries (LMICs) were reviewed using i) 93 media reports and ii) 17 published scientific papers. This review showed that those who suffered the most from the lockdown were migrants, workers in the large informal sector, small businesses, slum dwellers, women and elderly, revealing the social, cultural and economic inequalities of societies. Financial and food support for the poor was inadequate and sometimes mismanaged. In the better organized societies, the resilience was stronger (South Korea, Kerala/India) but here also the poor had to suffer the most. It is strongly recommended that outbreak response strategies should particularly focus on the poor and vulnerable population.
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http://dx.doi.org/10.1080/20477724.2021.1878446DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8079077PMC
May 2021

The Effectiveness of Intraosseous Basivertebral Nerve Radiofrequency Neurotomy for the Treatment of Chronic Low Back Pain in Patients with Modic Changes: A Systematic Review.

Pain Med 2021 05;22(5):1039-1054

Division of Physical Medicine and Rehabilitation, University of Utah, Salt Lake City, Utah, USA.

Objective: Determine the effectiveness of intraosseous basivertebral nerve radiofrequency neurotomy for the treatment of chronic low back pain with type 1 or 2 Modic changes.

Design: Systematic review.

Population: Persons aged ≥18 years with chronic low back pain with type 1 or 2 Modic changes.

Intervention: Intraosseous basivertebral nerve radiofrequency neurotomy.

Comparison: Sham, placebo procedure, active standard care treatment, or none.

Outcomes: The primary outcome of interest was the proportion of individuals with ≥50% pain reduction. Secondary outcomes included ≥10-point improvement in function as measured by Oswestry Disability Index as well as ≥2-point reduction in pain score on the Visual Analog Scale or Numeric Rating Scale, and decreased use of pain medication.

Methods: Three reviewers independently assessed publications before May 15, 2020, in MEDLINE and Embase and the quality of evidence was evaluated using the Grades of Recommendation, Assessment, Development, and Evaluation framework.

Results: Of the 725 publications screened, seven publications with 321 participants were ultimately included. The reported 3-month success rate for ≥50% pain reduction ranged from 45% to 63%. Rates of functional improvement (≥10-point Oswestry Disability Index improvement threshold) ranged from 75% to 93%. For comparison to sham treatment, the relative risk of treatment success defined by ≥50% pain reduction and ≥10-point Oswestry Disability Index improvement was 1.25 (95% confidence interval [CI]: .88-1.77) and 1.38 (95% CI: 1.10-1.73), respectively. For comparison to continued standard care treatment the relative risk of treatment success defined by ≥50% pain reduction and ≥10-point Oswestry Disability Index improvement was 4.16 (95% CI: 2.12-8.14) and 2.32 (95% CI: 1.52-3.55), respectively.

Conclusions: There is moderate-quality evidence that suggests this procedure is effective in reducing pain and disability in patients with chronic low back pain who are selected based on type 1 or 2 Modic changes, among other inclusion and exclusion criteria used in the published literature to date. Success of the procedure appears to be dependent on effective targeting of the BVN. Non-industry funded high-quality, large prospective studies are needed to confirm these findings.
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http://dx.doi.org/10.1093/pm/pnab040DOI Listing
May 2021

BRAIN LESION DETECTION USING A ROBUST VARIATIONAL AUTOENCODER AND TRANSFER LEARNING.

Proc IEEE Int Symp Biomed Imaging 2020 Apr 22;2020:786-790. Epub 2020 May 22.

Signal and Image Processing Institute, University of Southern California, Los Angeles.

Automated brain lesion detection from multi-spectral MR images can assist clinicians by improving sensitivity as well as specificity. Supervised machine learning methods have been successful in lesion detection. However, these methods usually rely on a large number of manually delineated images for specific imaging protocols and parameters and often do not generalize well to other imaging parameters and demographics. Most recently, unsupervised models such as autoencoders have become attractive for lesion detection since they do not need access to manually delineated lesions. Despite the success of unsupervised models, using pre-trained models on an unseen dataset is still a challenge. This difficulty is because the new dataset may use different imaging parameters, demographics, and different pre-processing techniques. Additionally, using a clinical dataset that has anomalies and outliers can make unsupervised learning challenging since the outliers can unduly affect the performance of the learned models. These two difficulties make unsupervised lesion detection a particularly challenging task. The method proposed in this work addresses these issues using a two-prong strategy: (1) we use a robust variational autoencoder model that is based on robust statistics, specifically the -divergence that can be trained with data that has outliers; (2) we use a transfer-learning method for learning models across datasets with different characteristics. Our results on MRI datasets demonstrate that we can improve the accuracy of lesion detection by adapting robust statistical models and transfer learning for a variational autoencoder model.
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http://dx.doi.org/10.1109/isbi45749.2020.9098405DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7831448PMC
April 2020

A NETWORK-BASED APPROACH TO STUDY OF ADHD USING TENSOR DECOMPOSITION OF RESTING STATE FMRI DATA.

Proc IEEE Int Symp Biomed Imaging 2020 Apr 22;2020:544-548. Epub 2020 May 22.

Signal and Image Processing Institute, University of Southern California.

Identifying changes in functional connectivity in Attention Deficit Hyperactivity Disorder (ADHD) using functional magnetic resonance imaging (fMRI) can help us understand the neural substrates of this brain disorder. Many studies of ADHD using resting state fMRI (rs-fMRI) data have been conducted in the past decade with either manually crafted features that do not yield satisfactory performance, or automatically learned features that often lack interpretability. In this work, we present a tensor-based approach to identify brain networks and extract features from rs-fMRI data. Results show the identified networks are interpretable and consistent with our current understanding of ADHD conditions. The extracted features are not only predictive of ADHD score but also discriminative for classification of ADHD subjects from typically developed children.
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http://dx.doi.org/10.1109/isbi45749.2020.9098584DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7831393PMC
April 2020

Clofazimine-related duodenal pigmentation.

Indian J Gastroenterol 2021 Jun;40(3):347-348

Division of Gastroenterology, P D Hinduja Hospital and MRC, Mumbai, 400 016, India.

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http://dx.doi.org/10.1007/s12664-020-01128-6DOI Listing
June 2021

Robust brain network identification from multi-subject asynchronous fMRI data.

Neuroimage 2021 02 8;227:117615. Epub 2020 Dec 8.

Signal and Image Processing Institute, University of Southern California, Los Angeles, CA 90089, United States.

We describe a novel method for robust identification of common brain networks and their corresponding temporal dynamics across subjects from asynchronous functional MRI (fMRI) using tensor decomposition. We first temporally align asynchronous fMRI data using the orthogonal BrainSync transform, allowing us to study common brain networks across sessions and subjects. We then map the synchronized fMRI data into a 3D tensor (vertices × time × subject/session). Finally, we apply Nesterov-accelerated adaptive moment estimation (Nadam) within a scalable and robust sequential Canonical Polyadic (CP) decomposition framework to identify a low rank tensor approximation to the data. As a result of CP tensor decomposition, we successfully identified twelve known brain networks with their corresponding temporal dynamics from 40 subjects using the Human Connectome Project's language task fMRI data without any prior information regarding the specific task designs. Seven of these networks show distinct subjects' responses to the language task with differing temporal dynamics; two show sub-components of the default mode network that exhibit deactivation during the tasks; the remaining three components reflect non-task-related activities. We compare results to those found using group independent component analysis (ICA) and canonical ICA. Bootstrap analysis demonstrates increased robustness of networks found using the CP tensor approach relative to ICA-based methods.
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http://dx.doi.org/10.1016/j.neuroimage.2020.117615DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7983296PMC
February 2021

In vitro evaluation of the metabolic enzymes and drug interaction potential of triapine.

Cancer Chemother Pharmacol 2020 11 28;86(5):633-640. Epub 2020 Sep 28.

Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA, 15261, USA.

Purpose: To investigate the metabolic pathways of triapine in primary cultures of human hepatocytes and human hepatic subcellular fractions; to investigate interactions of triapine with tenofovir and emtricitabine; and to evaluate triapine as a perpetrator of drug interactions. The results will better inform future clinical studies of triapine, a radiation sensitizer currently being studied in a phase III study.

Methods: Triapine was incubated with human hepatocytes and subcellular fractions in the presence of a number of inhibitors of drug metabolizing enzymes. Triapine depletion was monitored by LC-MS/MS. Tenofovir and emtricitabine were co-incubated with triapine in primary cultures of human hepatocytes. Triapine was incubated with a CYP probe cocktail and human liver microsomes, followed by LC-MS/MS monitoring of CYP specific metabolite formation.

Results: Triapine was not metabolized by FMO, AO/XO, MAO-A/B, or NAT-1/2, but was metabolized by CYP450s. CYP1A2 accounted for most of the depletion of triapine. Tenofovir and emtricitabine did not alter triapine depletion. Triapine reduced CYP1A2 activity and increased CYP2C19 activity.

Conclusion: CYP1A2 metabolism is the major metabolic pathway for triapine. Triapine may be evaluated in cancer patients in the setting of HIV with emtricitabine or tenofovir treatment. Confirmatory clinical trials may further define the in vivo triapine metabolic fate and quantify any drug-drug interactions.
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http://dx.doi.org/10.1007/s00280-020-04154-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7906094PMC
November 2020

Evaluation of the pharmacokinetic drug-drug interaction potential of iohexol, a renal filtration marker.

Cancer Chemother Pharmacol 2020 10 18;86(4):535-545. Epub 2020 Sep 18.

Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA, USA.

Purpose: Carboplatin dose is calculated based on kidney function, commonly estimated with imperfect creatinine-based formulae. Iohexol is used to measure glomerular filtration rate (GFR) and allows calculation of a more appropriate carboplatin dose. To address potential concerns that iohexol administered during a course of chemotherapy impacts that therapy, we performed in vitro and in vivo pharmacokinetic drug-drug interaction evaluations of iohexol.

Methods: Carboplatin was administered IV to female mice at 60 mg/kg with or without iohexol at 300 mg/kg. Plasma ultrafiltrate, kidney and bone marrow platinum was quantitated by atomic absorption spectrophotometry. Paclitaxel microsomal and gemcitabine cytosolic metabolism as well as metabolism of CYP and UGT probes was assessed with and without iohexol at 300 µg/mL by LC-MS/MS.

Results: In vivo carboplatin exposure was not significantly affected by iohexol co-administration (platinum AUC combination vs alone: plasma ultrafiltrate 1,791 vs 1920 µg/mL min; kidney 8367 vs 9757 µg/g min; bone marrow 12.7 vs 12.7 µg/mg-protein min). Paclitaxel microsomal metabolism was not impacted (combination vs alone: 6-α-OH-paclitaxel 38.3 versus 39.4 ng/mL/60 min; 3-p-OH-paclitaxel 26.2 versus 27.7 ng/mL/60 min). Gemcitabine human cytosolic elimination was not impacted (AUC combination vs gemcitabine alone: dFdU 24.1 versus 23.7 µg/mL/30 min). Iohexol displayed no relevant inhibition of the CYP and UGT enzymes in human liver microsomes.

Conclusions: Iohexol is unlikely to affect the clinical pharmacokinetics of carboplatin, paclitaxel, gemcitabine, or other agents used in combination with carboplatin treatment. Measuring GFR with iohexol to better dose carboplatin is unlikely to alter the safety or efficacy of chemotherapy through pharmacokinetic drug-drug interactions.
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http://dx.doi.org/10.1007/s00280-020-04145-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7521612PMC
October 2020

Soil-transmitted helminthiasis in four districts in Bangladesh: household cluster surveys of prevalence and intervention status.

BMC Public Health 2020 May 12;20(1):672. Epub 2020 May 12.

Elimination of Lymphatic Filariasis & STH Control Program, Directorate General of Health Services, Ministry of Health & Family Welfare, Road # 29, New DOHS, Mohakhali, Dhaka, Bangladesh.

Background: In 2016, after 8 years of twice-annual nationwide preventive chemotherapy (PC) administration to school-age children (SAC), the Bangladesh Ministry of Health & Family Welfare (MOHFW) sought improved impact and intervention monitoring data to assess progress toward the newly adopted goal of eliminating soil-transmitted helminthiasis (STH) as a public health problem.

Methods: We surveyed four Bangladeshi districts between August and October 2017. We conducted a multi-stage, cluster-sample, household survey which produced equal-probability samples for preschool-age children (PSAC; 1-4 years), SAC (5-14 years), and adults (≥ 15 years). Standardized questionnaires were administered, using Android-based smart phones running an Open Data Kit application. Stool samples were collected and testing for STH prevalence and infection intensity used the Kato-Katz technique.

Results: In all, 4318 stool samples were collected from 7164 participants. Estimates of STH prevalence by risk group in three of the four surveyed districts ranged from 3.4 to 5.0%, all with upper, 1-sided 95% confidence limits < 10%. However, STH prevalence estimates in Sirajganj District ranged from 23.4 to 29.1%. Infections in that district were spatially focal; four of the 30 survey clusters had > 50% prevalence in at least one risk group. Among all tested specimens, Ascaris lumbricoides was the most common STH parasite [8.2% (n = 352)], followed by Trichuris trichiura [0.9% (n = 37)], and hookworm [0.6% (n = 27)]. In each district, PC coverage among SAC was above the 75% program target but did not exceed 45% among PSAC in any district. Improved sanitation at home, school, or work was over 90% in all districts.

Conclusions: In the three low-prevalence districts, the MOHFW is considering decreasing the frequency of mass drug administration, per World Health Organization (WHO) guidelines. Also, the MOHFW will focus programmatic resources and supervisory efforts on Sirajganj District. Despite considering WHO guidance, the MOHFW will not expand PC administration to women of reproductive age partly due to the low prevalence of hookworm and T. trichiura, the STH parasites that contribute most to morbidity in that risk group. Data collected from surveys such as ours would help effectively guide future STH control efforts in Bangladesh and elsewhere.
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http://dx.doi.org/10.1186/s12889-020-08755-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7218586PMC
May 2020

Diarrhea in kidney transplant recipients: Etiology and outcome.

Indian J Gastroenterol 2020 04 29;39(2):141-146. Epub 2020 Apr 29.

Division of Nephrology, P D Hinduja Hospital, Mahim, Mumbai, 400 016, India.

Background And Aim: Diarrhea in kidney transplant recipients influences outcome of transplantation. Data from India in this regard are sparse and do not address the differential outcome of infective and non-infective diarrhea. We studied the demographic data, laboratory findings, treatment response, disease duration, and outcome of diarrhea in kidney transplant recipients, and the differential outcome between infective and non-infective diarrhea, if any.

Methods: All kidney transplant recipients who were referred to the Division of Gastroenterology with diarrhea between June 2015 and February 2017 were prospectively included. Demographic, clinical and laboratory data, graft function, treatment administered, and outcome were noted, and the patients were followed up for 3 months.

Results: Forty-seven patients (median age 45 years, range 16-78; 34 men) with 64 episodes of diarrhea were studied. Thirty-three (51.5%) episodes were attributed to infections. Eleven (17%) were immunosuppressant-induced (mycophenolate 8, tacrolimus 2, cyclosporine 1). Twenty (31%) were due to other causes (antibiotics 6, laxatives 3, irritable bowel syndrome 3, sepsis 8). Fifty-three episodes (82%) had graft dysfunction during the diarrheal episodes. Mean increase in serum creatinine was 45% in the infectious diarrhea group and 95% in the non-infectious diarrhea group (p < 0.05). Median time to resolution of diarrhea was 3 days. With improvement in diarrhea, return to pre-diarrhea creatinine levels occurred in 87% of episodes at 3 months.

Conclusion: One-half of episodes of diarrhea in kidney transplant recipients were non-infectious in origin. Seventeen percent were attributed to immunosuppressants, requiring dose modification. More than 80% were associated with worsening of graft function. Recovery of graft function to baseline was seen in a majority of cases with the resolution of diarrhea.
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http://dx.doi.org/10.1007/s12664-020-01022-1DOI Listing
April 2020

A Matched Filter Decomposition of fMRI into Resting and Task Components.

Med Image Comput Comput Assist Interv 2019 Oct 10;11766:673-681. Epub 2019 Oct 10.

University of Southern California, Los Angeles, CA, USA.

The human brain exhibits dynamic interactions among brain regions when responding to stimuli and executing tasks, which can be recorded using functional magnetic resonance imaging (fMRI). Functional MRI signals collected in response to specific tasks consist of a combination of task-related and spontaneous (task-independent) activity. By exploiting the highly structured spatiotemporal patterns of resting state networks, this paper presents a matched-filter approach to decomposing fMRI signals into task and resting-state components. To perform the decomposition, we first use a temporal alignment procedure that is a windowed version of the brainsync transform to synchronize a resting template to the brain's response to tasks. The resulting 'matched filter' removes the components of the fMRI signal that can be described by resting connectivity, leaving the portion of brain activity directly related to tasks. We present a closed-form expression for the windowed synchronization transform that is used by the matched filter. We demonstrate performance of this procedure in application to motor task and language task fMRI data. We show qualitatively and quantitatively that by removing the resting activity, we are able to identify task activated regions in the brain more clearly. Additionally, we show improved prediction accuracy in multivariate pattern analysis when using the matched filtered fMRI data.
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http://dx.doi.org/10.1007/978-3-030-32248-9_75DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7065573PMC
October 2019

Housing structure including the surrounding environment as a risk factor for visceral leishmaniasis transmission in Nepal.

PLoS Negl Trop Dis 2020 03 9;14(3):e0008132. Epub 2020 Mar 9.

Central Department of Microbiology, Tribhuvan University, Kirtipur, Kathmandu, Nepal.

Visceral leishmaniasis (VL) in Nepal is found in 61 out of 75 districts including areas previously listed as non- endemic. This study focused on the role of housing conditions and its immediate environment in VL transmission, to limit future transmissions, ensure sustainable vector control and support the VL elimination program. The objective was to explore the risk factors in rural housing-and land lot typologies contributing to clinical VL occurrence and transmission. Housing structures and land lots were examined based on characteristics as risk factors of VL transmission in a case-control analysis. VL cases from 2013-2017 were identified based on the existing database from the Epidemiology and Disease Control Division and District Public Health Office from the plain Terai area (Morang, and Saptari districts) and hilly area (Palpa district) of Nepal. Two hundred and three built environments were analyzed (66 cases and 137 controls). Inferential statistics and logistic regression analysis were performed to determine the association of risk factors with VL. The risk factors with the highest odds of VL were: bamboo walls (adjusted odds ratio (AOR)- 8.1, 95% CI 2.40-27.63, p = 0.001), walls made of leaves/branches (AOR- 3.0, 95% CI 0.84-10.93, p = 0.090), cracks in bedroom walls (AOR- 2.9, 95% CI 0.93-9.19, p = 0.065), and placing sacks near sleeping areas (AOR- 19.2, 95% CI 4.06-90.46, p <0.001). Significant outdoor factors were: lots with Kadam trees (AOR- 12.7, 95% CI 3.28-49.09, p <0.001), open ground-outdoor toilets (AOR- 9.3, 95% CI 2.14-369.85, p = 0.003), moisture in outdoor toilet sheds (AOR- 18.09, 95% CI 7.25-451.01, p = 0.002), nearby- open land (AOR- 36.8, 95% CI 3.14-430.98, p = 0.004), moisture inside animal sheds (AOR- 6.9, 95% CI 1.82-26.66, p = 0.005), and surrounding animals/animals wastes particularly goats (AOR- 3.5, 95% CI 1.09-10.94, p = 0.036). Certain housing and surrounding environmental conditions and characteristics are risk factors for VL. Hence, elimination and educational programs should include the focus on housing improvement and avoidance of risk factors. Longitudinal interventional studies are required to document temporal relationships and whether interventions on these factors will have an impact on Leishmania transmission or burden.
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http://dx.doi.org/10.1371/journal.pntd.0008132DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7062236PMC
March 2020

Role of female community health volunteers for visceral leishmaniasis detection and vector surveillance in Nepal.

Health Promot Perspect 2020 28;10(1):50-58. Epub 2020 Jan 28.

Central Department of Microbiology, Tribhuvan University, Kirtipur, Kathmandu, Nepal.

As visceral leishmaniasis (VL) has recently expanded in previously non-endemic areas of Nepal, the health system is facing new challenges. Female community health volunteers(FCHVs) are playing an important role for VL elimination in Nepal. This study aimed to analyze the actual and potential role of FCHVs for VL elimination program as well as community awareness of the disease (VL) and protective measures. We used a concurrent embedded mixed methods design. Qualitative data were collected through in-depth interviews and focus group discussions with FCHVs of 22 VLendemic villages of 3 districts. Concurrently quantitative data were collected through formal interviews of 203 household heads of the same villages. FCHVs are able to perform their duties in an efficient way with the support of their families and specific incentives. FCHVs in the VL-endemic region have a good ability to recognize the VL suspects and refer to health facilities. The feedback by the district health office on referred patients was weak thus missing the opportunity of involving FCHVs in the 6-months follow up. In houses with a previous VL case knowledge levels of prevention and treatment ofVL were significantly better than in houses without a previous VL case. More people in houses with a former VL patient were aware on VL transmission. FCHVs are playing an important role for VL elimination in Nepal through detection of suspected cases and referral and may play a role in vector surveillance.
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http://dx.doi.org/10.15171/hpp.2020.09DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7036200PMC
January 2020

The FAST graph: A novel framework for the anatomically-guided visualization and analysis of cortico-cortical evoked potentials.

Epilepsy Res 2020 03 9;161:106264. Epub 2020 Jan 9.

Department of Neurology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA.

Background: Intracerebral electroencephalography (iEEG) using stereoelectroencephalography (SEEG) methodology for epilepsy surgery gives rise to complex data sets. The neurophysiological data obtained during the in-patient period includes categorization of the evoked potentials resulting from direct electrical cortical stimulation such as cortico-cortical evoked potentials (CCEPs). These potentials are recorded by hundreds of contacts, making these waveforms difficult to quickly interpret over such high-density arrays that are organized in three dimensional fashion.

New Method: The challenge in analyzing CCEPs data arises not just from the density of the array, but also from the stimulation of a number of different intracerebral sites. A systematic methodology for visualization and analysis of these evoked data is lacking. We describe the process of incorporating anatomical information into the visualizations, which are then compared to more traditional plotting techniques to highlight the usefulness of the new framework.

Results: We describe here an innovative framework for sorting, registering, labeling, ordering, and quantifying the functional CCEPs data, using the anatomical labelling of the brain, to provide an informative visualization and summary statistics which we call the "FAST graph" (Functional-Anatomical STacked area graphs). The FAST graph analysis is used to depict the significant CCEPs responses in patient with focal epilepsy.

Conclusions: The novel plotting approach shown here allows us to visualize high-density stimulation data in a single summary plot for subsequent detailed analyses. Improving the visual presentation of complex data sets aides in enhancing the clinical utility of the data.
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http://dx.doi.org/10.1016/j.eplepsyres.2020.106264DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7206791PMC
March 2020

Temporal non-local means filtering for studies of intrinsic brain connectivity from individual resting fMRI.

Med Image Anal 2020 04 7;61:101635. Epub 2020 Jan 7.

Signal and Image Processing Institute, University of Southern California, Los Angeles 90089 USA.

Characterizing functional brain connectivity using resting functional magnetic resonance imaging (fMRI) is challenging due to the relatively small Blood-Oxygen-Level Dependent contrast and low signal-to-noise ratio. Denoising using surface-based Laplace-Beltrami (LB) or volumetric Gaussian filtering tends to blur boundaries between different functional areas. To overcome this issue, a time-based Non-Local Means (tNLM) filtering method was previously developed to denoise fMRI data while preserving spatial structure. The kernel and parameters that define the tNLM filter need to be optimized for each application. Here we present a novel Global PDF-based tNLM filtering (GPDF) algorithm that uses a data-driven kernel function based on a Bayes factor to optimize filtering for spatial delineation of functional connectivity in resting fMRI data. We demonstrate its performance relative to Gaussian spatial filtering and the original tNLM filtering via simulations. We also compare the effects of GPDF filtering against LB filtering using individual in-vivo resting fMRI datasets. Our results show that LB filtering tends to blur signals across boundaries between adjacent functional regions. In contrast, GPDF filtering enables improved noise reduction without blurring adjacent functional regions. These results indicate that GPDF may be a useful preprocessing tool for analyses of brain connectivity and network topology in individual fMRI recordings.
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http://dx.doi.org/10.1016/j.media.2020.101635DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7062584PMC
April 2020

Evidence for visceral leishmaniasis elimination in Nepal.

Lancet Glob Health 2020 02;8(2):e161-e162

Public Health and Infectious Disease Research Center, New Baneshwor, Kathmandu, Nepal.

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http://dx.doi.org/10.1016/S2214-109X(19)30538-8DOI Listing
February 2020

A systematic review on powder mixed electrical discharge machining.

Heliyon 2019 Dec 2;5(12):e02963. Epub 2019 Dec 2.

Mechatronics Engineering Department, G. H. Patel College of Engineering & Technology, V. V. Nagar, Gujarat, India.

The advancement in the field of material science has gifted us new electrically conductive materials having good mechanical properties and thermal characteristics. Machining these materials using conventional machining process is a challenging task. Electrical discharge machining (EDM) is a well-established machining process used to manufacture process hard materials having geometrically complex shapes, that are extremely difficult to machine traditionally. EDM is a thermo-electric process in which material is eroded by rapidly recurring sparks between the non-contacted electrode and workpiece. As there is no direct contact between the electrodes in EDM, machining defects like mechanical stresses, clattering & vibration do not create problems during machining. In spite of the advantages of the process, its use in industry is limited owing to poor surface finish and low volumetric material removal. To overcome these drawbacks, the metallic powder is mixed in the dielectric fluid, which increases its conductive strength and increases the spark gap distance between the tool and workpiece. This new evolved material removal process is called Powder Mixed Electrical Discharge Machining (PMEDM). The added powder significantly affects the performance of the EDM process. The objective of this review is to benefit the researchers to understand the PMEDM concept precisely and study the process parameters furthermore in particulars to get enhancements in the process to achieve better quality levels.
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http://dx.doi.org/10.1016/j.heliyon.2019.e02963DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6909068PMC
December 2019

A clinical comparative study to assess the efficacy of a new centric registration technique with a conventional technique.

J Indian Prosthodont Soc 2019 Oct-Dec;19(4):290-295. Epub 2019 Oct 10.

Department of Prosthodontics, School of Dental Sciences, Krishna Institute of Medical Sciences and Deemed University, Karad, Maharashtra, India.

Aim: The aim and objectives of this study were to assess and compare the efficacy of a new copyrighted technique (wax ball technique, L-77997/2018) and design (denture base design for the wax ball technique, L-78006/2018) for recording centric relation (CR).

Settings And Designs: - comparative study.

Materials And Methods: This study was conducted on sixty consented edentulous patients. The study participants were divided into Group I and Group II. CR in Group I patients was recorded using Dawson's bimanual technique (technique 1). For participants in Group II, CR was recorded using the authors' copyrighted technique (technique 2). Time taken and accuracy of CR records by both the techniques were evaluated.

Statistical Analysis Used: Descriptive statistics such as frequency and percentage were calculated for categorical variables, mean and standard deviation were calculated for quantitative variables. Independent -test was used to compare the time taken to record the CR between the two groups. The accuracy of both the techniques was assessed by Mann-Whitney U-test.

Results: The mean time taken for technique 1 was 56.47 s, whereas for technique 2, it was 5.97 s, with an overall mean difference of 50.5 s between the two techniques. Both techniques were found to be accurate, as the CR recorded during jaw relation matched with CR during trial in all the cases in both the groups (frequency 30 (N) and cumulative percentage 100%).

Conclusion: From the study, it was found that, time taken for technique 2 was statistically less compared to that of technique 1, and both the techniques were found to be equally accurate.
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http://dx.doi.org/10.4103/jips.jips_126_19DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6803795PMC
October 2019

Systematic review of diagnostic accuracy of patient history, clinical findings, and physical tests in the diagnosis of lumbar spinal stenosis.

Eur Spine J 2020 01 16;29(1):93-112. Epub 2019 Jul 16.

Department of Orthopaedic Surgery, Division of Physical Therapy, Duke University School of Medicine, 2200 W. Main St., Durham, NC, 27701, USA.

Purpose: To update evidence of diagnostic potential for identification of lumbar spinal stenosis (LSS) based on demographic and patient history, clinical findings, and physical tests, and report posttest probabilities associated with test findings.

Methods: An electronic search of PubMed, CINAHL and Embase was conducted combining terms related to low back pain, stenosis and diagnostic accuracy. Prospective or retrospective studies investigating diagnostic accuracy of LSS using patient history, clinical findings and/or physical tests were included. The risk of bias and applicability were assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS 2) tool. Diagnostic accuracy including sensitivities (SN), specificities (SP), likelihood ratios (+LR and -LR) and posttest probabilities (+PTP and -PTP) with 95% confidence intervals were summarized.

Results: Nine studies were included (pooled n = 36,228 participants) investigating 49 different index tests (30 demographic and patient history and 19 clinical findings/physical tests). Of the nine studies included, only two exhibited a low risk of bias and seven exhibited good applicability according to QUADAS 2. The demographic and patient history measures (self-reported history questionnaire, no pain when seated, numbness of perineal region) and the clinical findings/physical tests (two-stage treadmill test, symptoms after a March test and abnormal Romberg test) highly improved positive posttest probability by > 25% to diagnose LSS.

Conclusion: Outside of one study that was able to completely rule out LSS with no functional neurological changes none of the stand-alone findings were strong enough to rule in or rule out LSS. These slides can be retrieved under Electronic Supplementary Material.
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http://dx.doi.org/10.1007/s00586-019-06048-4DOI Listing
January 2020

Anemia predicts lower white matter volume and cognitive performance in sickle and non-sickle cell anemia syndrome.

Am J Hematol 2019 10 23;94(10):1055-1065. Epub 2019 Jul 23.

Division of Hematology, Oncology and Blood and Marrow Transplantation, Children's Hospital Los Angeles, Los Angeles, California.

Severe chronic anemia is an independent predictor of overt stroke, white matter damage, and cognitive dysfunction in the elderly. Severe anemia also predisposes to white matter strokes in young children, independent of the anemia subtype. We previously demonstrated symmetrically decreased white matter (WM) volumes in patients with sickle cell disease (SCD). In the current study, we investigated whether patients with non-sickle anemia also have lower WM volumes and cognitive dysfunction. Magnetic Resonance Imaging was performed on 52 clinically asymptomatic SCD patients (age = 21.4 ± 7.7; F = 27, M = 25; hemoglobin = 9.6 ± 1.6 g/dL), 26 non-sickle anemic patients (age = 23.9 ± 7.9; F = 14, M = 12; hemoglobin = 10.8 ± 2.5 g/dL) and 40 control subjects (age = 27.7 ± 11.3; F = 28, M = 12; hemoglobin = 13.4 ± 1.3 g/dL). Voxel-wise changes in WM brain volumes were compared to hemoglobin levels to identify brain regions that are vulnerable to anemia. White matter volume was diffusely lower in deep, watershed areas proportionally to anemia severity. After controlling for age, sex, and hemoglobin level, brain volumes were independent of disease. WM volume loss was associated with lower Full Scale Intelligence Quotient (FSIQ; P = .0048; r = .18) and an abnormal burden of silent cerebral infarctions (P = .029) in males, but not in females. Hemoglobin count and cognitive measures were similar between subjects with and without white-matter hyperintensities. The spatial distribution of volume loss suggests chronic hypoxic cerebrovascular injury, despite compensatory hyperemia. Neurocognitive consequences of WM volume changes and silent cerebral infarction were strongly sexually dimorphic. Understanding the possible neurological consequences of chronic anemia may help inform our current clinical practices.
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http://dx.doi.org/10.1002/ajh.25570DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6857783PMC
October 2019

Degenerative Disc Disease: What is in a Name?

Spine (Phila Pa 1976) 2019 Nov;44(21):1523-1529

Department of General Internal Medicine, University of Washington, Seattle, WA.

Study Design: A systematic search and review OBJECTIVE.: The aim of this study was to investigate the term, degenerative disc disease, to elucidate its current usage and inform clinical, research, and policy recommendations.

Summary Of Background Data: Degenerative disc disease has long been a dominant concept in common, painful spinal disorders. Yet, despite its pervasiveness and important clinical consequences and controversies, there has not been a systematic examination of its use and meaning in the scientific literature.

Methods: We conducted a systematic search of publications using the term degenerative disc disease from 2007 through 2016 in Ovid MEDLINE (R), Embase, CINAHL, and Scopus. Two investigators independently reviewed all publications in the primary sample. Publication and author identifiers, and qualitative study descriptors were extracted. Finally, the definition of degenerative disc disease was placed in one of eight categories. Data were summarized using descriptive statistics.

Results: Degenerative disc disease appeared in the titles of 402 publications in the primary sample and increased in frequency by 189% from the first to the last 3 years of the decade. No single definition was used in the majority of publications, and most frequently, the term was used without any definition provided (30.1%). In other cases, degenerative disc disease specifically included radiculopathy or myelopathy (14.4%), or only back or neck pain (5.5%), or was equated with disc degeneration regardless of the presence of symptoms (15.4%), or with discogenic pain or disc degeneration as a presumed cause of axial pain (12.7%). Another 7.2% comprised a mix of broad ranging findings and diagnoses. The most notable differences in definitions occurred between surgeons and other disciplines, and when applied to cervical versus lumbar regions.

Conclusion: Despite longstanding use and important consequences, degenerative disc disease represents an underdeveloped concept, with greatly varying, disparate definitions documented. Such inconsistencies challenge clear, accurate communication in medicine and science, create confusion and misconceptions among clinicians, patients and others, and hinder the advancement of related knowledge.

Level Of Evidence: 4.
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http://dx.doi.org/10.1097/BRS.0000000000003103DOI Listing
November 2019

The Source and the Course of the Articular Branches to the T4-T8 Zygapophysial Joints.

Pain Med 2019 12;20(12):2371-2376

Department of Basic Science, College of Osteopathic Medicine, Touro University, Vallejo, California.

Objective: To define the source and the course of the articular branches to the midthoracic zygapophysial ("z") joints.

Design: Cadaveric dissection.

Setting: The Gross Anatomy Laboratory of the Duke University School of Medicine.

Subjects: Ten human cadaveric thoraces.

Methods: Gross and stereoscopic dissection of dorsal rami T4-T8 was performed bilaterally on 10 adult embalmed cadavers. The medial and lateral branches were traced to their origins from the dorsal rami, and the course of the articular nerves was documented through digital photography. Radio-opaque wire (20 gauge) was applied to the nerves. Fluoroscopic images were obtained to delineate their radiographic course with respect to osseous landmarks.

Results: Forty-eight inferior articular branches were identified. Three (6.3%) originated from the medial branch and 44 (91.7%) from the dorsal ramus. One was indeterminate. Fifty-one superior articular branches were identified. Eight (15.7%) originated from the medial branch and 43 (84.3%) from the dorsal ramus. In 12% of cases (6/50), there was side-to-side asymmetry in the origins of the articular branches. Nerves were commonly suspended in the intertransverse space. The articular branches contacted an osseous structure in only 39% of cases. As previously reported, a "descending branch" was not identified in any specimen.

Conclusions: Articular branches to the T4-T8 z-joints have substantial inter- and intraspecimen variability of origin. They typically arise from the dorsal ramus rather than the medial branch and frequently do not contact any osseous structure to allow percutaneous needle placement.
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http://dx.doi.org/10.1093/pm/pnz116DOI Listing
December 2019

A principal component analysis-based framework for statistical modeling of bone displacement during wrist maneuvers.

J Biomech 2019 03 24;85:173-181. Epub 2019 Jan 24.

Department of Radiology, University of California Davis School of Medicine, Sacramento, CA 95817, USA. Electronic address:

We present a method for the statistical modeling of the displacements of wrist bones during the performance of coordinated maneuvers, such as radial-ulnar deviation (RUD). In our approach, we decompose bone displacement via a set of basis functions, identified via principal component analysis (PCA). We utilized MRI wrist scans acquired at multiple static positions for deriving these basis functions. We then utilized these basis functions to compare the displacements undergone by the bones of the left versus right wrist in the same individual, and between bones of the wrists of men and women, during the performance of the coordinated RUD maneuver. Our results show that the complex displacements of the wrist bones during RUD can be modeled with high reliability with just 5 basis functions, that captured over 91% of variation across individuals. The basis functions were able to predict intermediate wrist bone poses with an overall high accuracy (mean error of 0.26 mm). Our proposed approach found statistically significant differences between bone displacement trajectories in women versus men, however, did not find significant differences in those of the left versus right wrist in the same individual. Our proposed method has the potential to enable detailed analysis of wrist kinematics for each sex, and provide a robust framework for characterizing the normal and pathologic displacement of the wrist bones, such as in the context of wrist instability.
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http://dx.doi.org/10.1016/j.jbiomech.2019.01.030DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6434941PMC
March 2019

Using the Anisotropic Laplace Equation to Compute Cortical Thickness.

Med Image Comput Comput Assist Interv 2018 Sep 13;11072:549-556. Epub 2018 Sep 13.

University of Southern California, Los Angeles, CA, USA.

Automatic computation of cortical thickness is a critical step when investigating neuroanatomical population differences and changes associated with normal development and aging, as well as in neurodegenerative diseases including Alzheimer's and Parkinson's. Limited spatial resolution and partial volume effects, in which more than one tissue type is represented in each voxel, have a significant impact on the accuracy of thickness estimates, particularly if a hard intensity threshold is used to delineate cortical boundaries. We describe a novel method based on the anisotropic heat equation that explicitly accounts for the presence of partial tissue volumes to more accurately estimate cortical thickness. The anisotropic term uses gray matter fractions to incorporate partial tissue voxels into the thickness calculation, as demonstrated through simulations and experiments. We also show that the proposed method is robust to the effects of finite voxel resolution and blurring. In comparison to methods based on hard intensity thresholds, the heat equation based method yields results with in-vivo data that are more consistent with histological findings reported in the literature. We also performed a test-retest study across scanners that indicated improved consistency and robustness to scanner differences.
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http://dx.doi.org/10.1007/978-3-030-00931-1_63DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6363343PMC
September 2018
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