Publications by authors named "Kevin Carpenter"

50 Publications

On Residual Stress Development, Prevention, and Compensation in Metal Additive Manufacturing.

Materials (Basel) 2020 Jan 7;13(2). Epub 2020 Jan 7.

School of Mechanical, Industrial and Manufacturing Engineering, Oregon State University, Corvallis, OR 97331, USA.

One of the most appealing qualities of additive manufacturing (AM) is the ability to produce complex geometries faster than most traditional methods. The trade-off for this advantage is that AM parts are extremely vulnerable to residual stresses (RSs), which may lead to geometrical distortions and quality inspection failures. Additionally, tensile RSs negatively impact the fatigue life and other mechanical performance characteristics of the parts in service. Therefore, in order for AM to cross the borders of prototyping toward a viable manufacturing process, the major challenge of RS development must be addressed. Different AM technologies contain many unique features and parameters, which influence the temperature gradients in the part and lead to development of RSs. The stresses formed in AM parts are typically observed to be compressive in the center of the part and tensile on the top layers. To mitigate these stresses, process parameters must be optimized, which requires exhaustive and costly experimentations. Alternative to experiments, holistic computational frameworks which can capture much of the physics while balancing computational costs are introduced for rapid and inexpensive investigation into development and prevention of RSs in AM. In this review, the focus is on metal additive manufacturing, referred to simply as "AM", and, after a brief introduction to various AM technologies and thermoelastic mechanics, prior works on sources of RSs in AM are discussed. Furthermore, the state-of-the-art knowledge on RS measurement techniques, the influence of AM process parameters, current modeling approaches, and distortion prevention approaches are reported.
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http://dx.doi.org/10.3390/ma13020255DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7013685PMC
January 2020

Regarding the rights and duties of Clinical Laboratory Geneticists in genetic healthcare systems: results of a survey in over 50 countries.

Eur J Hum Genet 2019 12 10;27(12):1761-1762. Epub 2019 Jul 10.

Chief Executive Officer Human Genetic Society of Australasia, Surry Hills, NSW, Australia.

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http://dx.doi.org/10.1038/s41431-019-0470-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6870984PMC
December 2019

Integrating glycomics and genomics uncovers SLC10A7 as essential factor for bone mineralization by regulating post-Golgi protein transport and glycosylation.

Hum Mol Genet 2018 09;27(17):3029-3045

Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands.

Genomics methodologies have significantly improved elucidation of Mendelian disorders. The combination with high-throughput functional-omics technologies potentiates the identification and confirmation of causative genetic variants, especially in singleton families of recessive inheritance. In a cohort of 99 individuals with abnormal Golgi glycosylation, 47 of which being unsolved, glycomics profiling was performed of total plasma glycoproteins. Combination with whole-exome sequencing in 31 cases revealed a known genetic defect in 15 individuals. To identify additional genetic factors, hierarchical clustering of the plasma glycomics data was done, which indicated a subgroup of four patients that shared a unique glycomics signature of hybrid type N-glycans. In two siblings, compound heterozygous mutations were found in SLC10A7, a gene of unknown function in human. These included a missense mutation that disrupted transmembrane domain 4 and a mutation in a splice acceptor site resulting in skipping of exon 9. The two other individuals showed a complete loss of SLC10A7 mRNA. The patients' phenotype consisted of amelogenesis imperfecta, skeletal dysplasia, and decreased bone mineral density compatible with osteoporosis. The patients' phenotype was mirrored in SLC10A7 deficient zebrafish. Furthermore, alizarin red staining of calcium deposits in zebrafish morphants showed a strong reduction in bone mineralization. Cell biology studies in fibroblasts of affected individuals showed intracellular mislocalization of glycoproteins and a defect in post-Golgi transport of glycoproteins to the cell membrane. In contrast to yeast, human SLC10A7 localized to the Golgi. Our combined data indicate an important role for SLC10A7 in bone mineralization and transport of glycoproteins to the extracellular matrix.
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http://dx.doi.org/10.1093/hmg/ddy213DOI Listing
September 2018

Elevated plasma dihydroorotate in Miller syndrome: Biochemical, diagnostic and clinical implications, and treatment with uridine.

Mol Genet Metab 2016 09 14;119(1-2):83-90. Epub 2016 Jun 14.

Department of Medical Genomics, Royal Prince Alfred Hospital, The University of Sydney, NSW 2050, Australia. Electronic address:

Background: Miller syndrome (post-axial acrofacial dysostosis) arises from gene mutations for the mitochondrial enzyme dihydroorotate dehydrogenase (DHODH). Nonetheless, despite demonstrated loss of enzyme activity dihydroorotate (DHO) has not been shown to accumulate, but paradoxically urine orotate has been reported to be raised, confusing the metabolic diagnosis.

Methods: We analysed plasma and urine from a 4-year-old male Miller syndrome patient. DHODH mutations were determined by PCR and Sanger sequencing. Analysis of DHO and orotic acid (OA) in urine, plasma and blood-spot cards was performed using liquid chromatography-tandem mass spectrometry. In vitro stability of DHO in distilled water and control urine was assessed for up to 60h. The patient received a 3-month trial of oral uridine for behavioural problems.

Results: The patient had early liver complications that are atypical of Miller syndrome. DHODH genotyping demonstrated compound-heterozygosity for frameshift and missense mutations. DHO was grossly raised in urine and plasma, and was detectable in dried spots of blood and plasma. OA was raised in urine but undetectable in plasma. DHO did not spontaneously degrade to OA. Uridine therapy did not appear to resolve behavioural problems during treatment, but it lowered plasma DHO.

Conclusion: This case with grossly raised plasma DHO represents the first biochemical confirmation of functional DHODH deficiency. DHO was also easily detectable in dried plasma and blood spots. We concluded that DHO oxidation to OA must occur enzymatically during renal secretion. This case resolved the biochemical conundrum in previous reports of Miller syndrome patients, and opened the possibility of rapid biochemical screening.
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http://dx.doi.org/10.1016/j.ymgme.2016.06.008DOI Listing
September 2016

Genome Evolution and Nitrogen Fixation in Bacterial Ectosymbionts of a Protist Inhabiting Wood-Feeding Cockroaches.

Appl Environ Microbiol 2016 08 15;82(15):4682-4695. Epub 2016 Jul 15.

Department of Botany, University of British Columbia, Vancouver, BC, Canada.

Unlabelled: By combining genomics and isotope imaging analysis using high-resolution secondary ion mass spectrometry (NanoSIMS), we examined the function and evolution of Bacteroidales ectosymbionts of the protist Barbulanympha from the hindguts of the wood-eating cockroach Cryptocercus punctulatus In particular, we investigated the structure of ectosymbiont genomes, which, in contrast to those of endosymbionts, has been little studied to date, and tested the hypothesis that these ectosymbionts fix nitrogen. Unlike with most obligate endosymbionts, genome reduction has not played a major role in the evolution of the Barbulanympha ectosymbionts. Instead, interaction with the external environment has remained important for this symbiont as genes for synthesis of transporters, outer membrane proteins, lipopolysaccharides, and lipoproteins have been retained. The ectosymbiont genome carried two complete operons for nitrogen fixation, a urea transporter, and a urease, indicating the availability of nitrogen as a driving force behind the symbiosis. NanoSIMS analysis of C. punctulatus hindgut symbionts exposed in vivo to (15)N2 supports the hypothesis that Barbulanympha ectosymbionts are capable of nitrogen fixation. This genomic and in vivo functional investigation of protist ectosymbionts highlights the diversity of evolutionary forces and trajectories that shape symbiotic interactions.

Importance: The ecological and evolutionary importance of symbioses is increasingly clear, but the overall diversity of symbiotic interactions remains poorly explored. In this study, we investigated the evolution and nitrogen fixation capabilities of ectosymbionts attached to the protist Barbulanympha from the hindgut of the wood-eating cockroach Cryptocercus punctulatus In addressing genome evolution of protist ectosymbionts, our data suggest that the ecological pressures influencing the evolution of extracellular symbionts clearly differ from intracellular symbionts and organelles. Using NanoSIMS analysis, we also obtained direct imaging evidence of a specific hindgut microbe playing a role in nitrogen fixation. These results demonstrate the power of combining NanoSIMS and genomics tools for investigating the biology of uncultivable microbes. This investigation paves the way for a more precise understanding of microbial interactions in the hindguts of wood-eating insects and further exploration of the diversity and ecological significance of symbiosis between microbes.
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http://dx.doi.org/10.1128/AEM.00611-16DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4984305PMC
August 2016

Modeling correction of severe urea cycle defects in the growing murine liver using a hybrid recombinant adeno-associated virus/piggyBac transposase gene delivery system.

Hepatology 2015 Aug 23;62(2):417-28. Epub 2015 May 23.

Gene Therapy Research Unit, Children's Medical Research Institute and The Children's Hospital at Westmead, Westmead, New South Wales, Australia.

Unlabelled: Liver-targeted gene therapy based on recombinant adeno-associated viral vectors (rAAV) shows promising therapeutic efficacy in animal models and adult-focused clinical trials. This promise, however, is not directly translatable to the growing liver, where high rates of hepatocellular proliferation are accompanied by loss of episomal rAAV genomes and subsequently a loss in therapeutic efficacy. We have developed a hybrid rAAV/piggyBac transposon vector system combining the highly efficient liver-targeting properties of rAAV with stable piggyBac-mediated transposition of the transgene into the hepatocyte genome. Transposition efficiency was first tested using an enhanced green fluorescent protein expression cassette following delivery to newborn wild-type mice, with a 20-fold increase in stably gene-modified hepatocytes observed 4 weeks posttreatment compared to traditional rAAV gene delivery. We next modeled the therapeutic potential of the system in the context of severe urea cycle defects. A single treatment in the perinatal period was sufficient to confer robust and stable phenotype correction in the ornithine transcarbamylase-deficient Spf(ash) mouse and the neonatal lethal argininosuccinate synthetase knockout mouse. Finally, transposon integration patterns were analyzed, revealing 127,386 unique integration sites which conformed to previously published piggyBac data.

Conclusion: Using a hybrid rAAV/piggyBac transposon vector system, we achieved stable therapeutic protection in two urea cycle defect mouse models; a clinically conceivable early application of this technology in the management of severe urea cycle defects could be as a bridging therapy while awaiting liver transplantation; further improvement of the system will result from the development of highly human liver-tropic capsids, the use of alternative strategies to achieve transient transposase expression, and engineered refinements in the safety profile of piggyBac transposase-mediated integration.
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http://dx.doi.org/10.1002/hep.27842DOI Listing
August 2015

Molecular Evidence for the Polyphyly of Macrotrichomonas (Parabasalia: Cristamonadea) and a Proposal for Macrotrichomonoides n. gen.

J Eukaryot Microbiol 2015 Jul-Aug;62(4):494-504. Epub 2015 Feb 12.

Department of Botany, Canadian Institute for Advanced Research, University of British Columbia, Vancouver, British Columbia, V6T 1Z4, Canada.

Macrotrichomonas (Cristamonadea: Parabasalia) is an anaerobic, amitochondriate flagellate symbiont of termite hindguts. It is noteworthy for being large but not structurally complex compared with other large parabasalians, and for retaining a structure similar in appearance to the undulating membrane (UM) of small flagellates closely related to cristamonads, e.g. Tritrichomonas. Here, we have characterised the SSU rDNA from two species described as Macrotrichomonas: M. restis Kirby 1942 from Neotermes jouteli and M. lighti Connell 1932 from Paraneotermes simplicicornis. These species do not form a clade: M. lighti branches with previously characterised Macrotrichomonas sequences from Glyptotermes, while M. restis branches with the genus Metadevescovina. We examined the M. restis UM by light microscopy, scanning electron microscopy, and transmission electron microscopy, and we find common characteristics with the proximal portion of the robust recurrent flagellum of devescovinids. Altogether, we show the genus Macrotrichomonas to be polyphyletic and propose transferring M. restis to a new genus, Macrotrichomonoides. We also hypothesise that the macrotrichomonad body plan represents the ancestral state of cristamonads, from which other major forms evolved.
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http://dx.doi.org/10.1111/jeu.12204DOI Listing
May 2016

Glycemic effects and safety of L-Glutamine supplementation with or without sitagliptin in type 2 diabetes patients-a randomized study.

PLoS One 2014 20;9(11):e113366. Epub 2014 Nov 20.

Diabetes and Metabolism Division, Garvan Institute of Medical Research, Sydney, Australia; Faculty of Medicine, UNSW (The University of New South Wales), Sydney, Australia; Department of Endocrinology and Diabetes Center, St. Vincent's Hospital, Sydney, Australia.

Background And Aims: L-glutamine is an efficacious glucagon-like peptide (GLP)-1 secretagogue in vitro. When administered with a meal, glutamine increases GLP-1 and insulin excursions and reduces postprandial glycaemia in type 2 diabetes patients. The aim of the study was to assess the efficacy and safety of daily glutamine supplementation with or without the dipeptidyl peptidase (DPP)-4 inhibitor sitagliptin in well-controlled type 2 diabetes patients.

Methods: Type 2 diabetes patients treated with metformin (n = 13, 9 men) with baseline glycated hemoglobin (HbA1c) 7.1±0.3% (54±4 mmol/mol) received glutamine (15 g bd)+ sitagliptin (100 mg/d) or glutamine (15 g bd) + placebo for 4 weeks in a randomized crossover study.

Results: HbA1c (P = 0.007) and fructosamine (P = 0.02) decreased modestly, without significant time-treatment interactions (both P = 0.4). Blood urea increased (P<0.001) without a significant time-treatment interaction (P = 0.8), but creatinine and estimated glomerular filtration rate (eGFR) were unchanged (P≥0.5). Red blood cells, hemoglobin, hematocrit, and albumin modestly decreased (P≤0.02), without significant time-treatment interactions (P≥0.4). Body weight and plasma electrolytes remained unchanged (P≥0.2).

Conclusions: Daily oral supplementation of glutamine with or without sitagliptin for 4 weeks decreased glycaemia in well-controlled type 2 diabetes patients, but was also associated with mild plasma volume expansion.

Trial Registration: ClincalTrials.gov NCT00673894.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0113366PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4239068PMC
January 2016

The phylogenetic position of Kofoidia loriculata (Parabasalia) and its implications for the evolution of the Cristamonadea.

J Eukaryot Microbiol 2015 Mar-Apr;62(2):255-9. Epub 2014 Sep 18.

Department of Botany, Canadian Institute for Advanced Research Program in Integrated Microbial Biodiversity, University of British Columbia, 3529-6270 University Blvd., Vancouver, British Columbia, Canada.

Kofoidia loriculata is a parabasalid symbiont inhabiting the hindgut of the lower termite Paraneotermes simplicicornis. It was initially described as a lophomonad due to its apical tuft of multiple flagella that disintegrate during cell division, but its phylogenetic relationships have not been investigated using molecular evidence. From single cell isolations, we sequenced the small subunit rRNA gene and determined that K. loriculata falls within the Cristamonadea, but is unrelated to other lophomonads. This analysis further demonstrates the polyphyly of the lophomonads and the necessity to re-assess the morphological and cellular evolution of the Cristamonadea.
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http://dx.doi.org/10.1111/jeu.12163DOI Listing
June 2015

Expanded newborn screening in New South Wales: missed cases.

J Inherit Metab Dis 2014 Nov 27;37(6):881-7. Epub 2014 Jun 27.

Department of Medical Genetics Westmead Hospital, Sydney, Australia.

There have been few reports of cases missed by expanded newborn screening. Tandem mass spectrometry was introduced in New South Wales, Australia in 1998 to screen for selected disorders of amino acid, organic acid and fatty acid metabolism. Of 1,500,000 babies screened by 2012, 1:2700 were diagnosed with a target disorder. Fifteen affected babies were missed by testing, and presented clinically or in family studies. In three cases (cobalamin C defect, very-long-chain acyl-CoA dehydrogenase deficiency and glutaric aciduria type 1), this led to modification of analyte cut-off values or protocols during the first 3 years. Two patients with intermittent MSUD, two with β-ketothiolase deficiency, two with citrin deficiency, two siblings with arginosuccinic aciduria, two siblings with homocystinuria, and one with cobalamin C defect had analyte values and ratios below the action limits which could not have been detected without unacceptable false-positive rates. A laboratory interpretation error led to missing one case of cobalamin C defect. Reference ranges, regularly reviewed, were not altered. For citrin deficiency, while relevant metabolites are detectable by tandem mass spectrometry, our cut-off values do not specifically screen for that disorder. Most of the missed cases are doing well and with no acute presentations although eight of 15 are likely to have been somewhat adversely affected by a late diagnosis. Analyte ratio and cut-off value optimisations are important, but for some disorders occasional missed cases may have to be tolerated to maintain an acceptable specificity, and avoid harm from screening.
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http://dx.doi.org/10.1007/s10545-014-9727-2DOI Listing
November 2014

Activating HSP72 in rodent skeletal muscle increases mitochondrial number and oxidative capacity and decreases insulin resistance.

Diabetes 2014 Jun 15;63(6):1881-94. Epub 2014 Jan 15.

Cellular and Molecular Metabolism Laboratory, Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, AustraliaN-Gene Research Laboratories, Inc., Budapest, Hungary

Induction of heat shock protein (HSP)72 protects against obesity-induced insulin resistance, but the underlying mechanisms are unknown. Here, we show that HSP72 plays a pivotal role in increasing skeletal muscle mitochondrial number and oxidative metabolism. Mice overexpressing HSP72 in skeletal muscle (HSP72Tg) and control wild-type (WT) mice were fed either a chow or high-fat diet (HFD). Despite a similar energy intake when HSP72Tg mice were compared with WT mice, the HFD increased body weight, intramuscular lipid accumulation (triacylglycerol and diacylglycerol but not ceramide), and severe glucose intolerance in WT mice alone. Whole-body VO2, fatty acid oxidation, and endurance running capacity were markedly increased in HSP72Tg mice. Moreover, HSP72Tg mice exhibited an increase in mitochondrial number. In addition, the HSP72 coinducer BGP-15, currently in human clinical trials for type 2 diabetes, also increased mitochondrial number and insulin sensitivity in a rat model of type 2 diabetes. Together, these data identify a novel role for activation of HSP72 in skeletal muscle. Thus, the increased oxidative metabolism associated with activation of HSP72 has potential clinical implications not only for type 2 diabetes but also for other disorders where mitochondrial function is compromised.
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http://dx.doi.org/10.2337/db13-0967DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4030108PMC
June 2014

Treatable childhood neuronopathy caused by mutations in riboflavin transporter RFVT2.

Brain 2014 Jan 19;137(Pt 1):44-56. Epub 2013 Nov 19.

1 Dubowitz Neuromuscular Centre and MRC Centre for Neuromuscular Disorders, University College London Institute of Child Health and Great Ormond Street Hospital for Children, London, WC1N 1EH, UK.

Childhood onset motor neuron diseases or neuronopathies are a clinically heterogeneous group of disorders. A particularly severe subgroup first described in 1894, and subsequently called Brown-Vialetto-Van Laere syndrome, is characterized by progressive pontobulbar palsy, sensorineural hearing loss and respiratory insufficiency. There has been no treatment for this progressive neurodegenerative disorder, which leads to respiratory failure and usually death during childhood. We recently reported the identification of SLC52A2, encoding riboflavin transporter RFVT2, as a new causative gene for Brown-Vialetto-Van Laere syndrome. We used both exome and Sanger sequencing to identify SLC52A2 mutations in patients presenting with cranial neuropathies and sensorimotor neuropathy with or without respiratory insufficiency. We undertook clinical, neurophysiological and biochemical characterization of patients with mutations in SLC52A2, functionally analysed the most prevalent mutations and initiated a regimen of high-dose oral riboflavin. We identified 18 patients from 13 families with compound heterozygous or homozygous mutations in SLC52A2. Affected individuals share a core phenotype of rapidly progressive axonal sensorimotor neuropathy (manifesting with sensory ataxia, severe weakness of the upper limbs and axial muscles with distinctly preserved strength of the lower limbs), hearing loss, optic atrophy and respiratory insufficiency. We demonstrate that SLC52A2 mutations cause reduced riboflavin uptake and reduced riboflavin transporter protein expression, and we report the response to high-dose oral riboflavin therapy in patients with SLC52A2 mutations, including significant and sustained clinical and biochemical improvements in two patients and preliminary clinical response data in 13 patients with associated biochemical improvements in 10 patients. The clinical and biochemical responses of this SLC52A2-specific cohort suggest that riboflavin supplementation can ameliorate the progression of this neurodegenerative condition, particularly when initiated soon after the onset of symptoms.
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http://dx.doi.org/10.1093/brain/awt315DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3891447PMC
January 2014

Correlated SEM, FIB-SEM, TEM, and NanoSIMS imaging of microbes from the hindgut of a lower termite: methods for in situ functional and ecological studies of uncultivable microbes.

Microsc Microanal 2013 Dec 11;19(6):1490-501. Epub 2013 Oct 11.

Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, P.O. Box 808, L-231, Livermore, CA 94551, USA.

The hindguts of lower termites harbor highly diverse, endemic communities of symbiotic protists, bacteria, and archaea essential to the termite's ability to digest wood. Despite over a century of experimental studies, ecological roles of many of these microbes are unknown, partly because almost none can be cultivated. Many of the protists associate with bacterial symbionts, but hypotheses for their respective roles in nutrient exchange are based on genomes of only two such bacteria. To show how the ecological roles of protists and nutrient transfer with symbiotic bacteria can be elucidated by direct imaging, we combined stable isotope labeling (13C-cellulose) of live termites with analysis of fixed hindgut microbes using correlated scanning electron microscopy, focused ion beam-scanning electron microscopy (FIB-SEM), transmission electron microscopy, and high resolution imaging mass spectrometry (NanoSIMS). We developed methods to prepare whole labeled cells on solid substrates, whole labeled cells milled with a FIB-SEM instrument to reveal cell interiors, and ultramicrotome sections of labeled cells for NanoSIMS imaging of 13C enrichment in protists and associated bacteria. Our results show these methods have the potential to provide direct evidence for nutrient flow and suggest the oxymonad protist Oxymonas dimorpha phagocytoses and enzymatically degrades ingested wood fragments, and may transfer carbon derived from this to its surface bacterial symbionts.
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http://dx.doi.org/10.1017/S1431927613013482DOI Listing
December 2013

Adeno-associated virus-mediated rescue of neonatal lethality in argininosuccinate synthetase-deficient mice.

Mol Ther 2013 Oct 2;21(10):1823-31. Epub 2013 Jul 2.

Gene Therapy Research Unit, Children's Medical Research Institute and The Children's Hospital at Westmead, Sydney, Australia.

Viral vectors based on adeno-associated virus (AAV) are showing exciting promise in gene therapy trials targeting the adult liver. A major challenge in extending this promise to the pediatric liver is the loss of episomal vector genomes that accompanies hepatocellular proliferation during liver growth. Hence maintenance of sufficient transgene expression will be critical for success in infants and children. We therefore set out to explore the therapeutic efficacy and durability of liver-targeted gene transfer in the challenging context of a neonatal lethal urea cycle defect, using the argininosuccinate synthetase deficient mouse. Lethal neonatal hyperammonemia was prevented by prenatal and early postnatal vector delivery; however, hyperammonemia subsequently recurred limiting survival to no more than 33 days despite vector readministration. Antivector antibodies acquired in milk from vector-exposed dams were subsequently shown to be blocking vector readministration, and were avoided by crossfostering vector-treated pups to vector-naive dams. In the absence of passively acquired antivector antibodies, vector redelivery proved efficacious with mice surviving to adulthood without recurrence of significant hyperammonemia. These data demonstrate the potential of AAV vectors in the developing liver, showing that vector readministration can be used to counter growth-associated loss of transgene expression provided the challenge of antivector humoral immunity is addressed.
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http://dx.doi.org/10.1038/mt.2013.139DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3808136PMC
October 2013

An unusual case of neck pain.

Pediatr Emerg Care 2013 May;29(5):644-5

Division of Pediatric Emergency Medicine, Department of Pediatrics, Medical University of South Carolina, Charleston, SC 29425, USA.

The complaint of nontraumatic neck pain in a pediatric patient without fever or any other symptoms is unusual and can be very challenging. We present the case of a 4-year-old boy with imaging consistent with a rare diagnosis. This report discusses this diagnosis as well as the utility of advanced imaging and laboratory evaluations in the presentation of pediatric neck pain.
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http://dx.doi.org/10.1097/PEC.0b013e31828e9e60DOI Listing
May 2013

Homocysteine measurement in dried blood spot for neonatal detection of homocystinurias.

JIMD Rep 2012 13;5:1-6. Epub 2011 Dec 13.

Discipline of Paediatrics and Child Health, University of Sydney, The Children's Hospital at Westmead Clinical School, Locked Bag 4001, Westmead, NSW, 2145, Australia.

Expanded newborn screening (NBS) leads to an increased number of false positive results, causing parental anxiety, greater follow-up costs, and the need for further metabolic investigations. We developed and validated a second-tier approach for NBS of homocystinurias by measuring the total homocysteine (tHcy) on the initial dried blood spot (DBS) samples to reduce the need for further investigation, and investigated newborn DBS homocysteine values in patients with homocystinuria. Total DBS homocysteine was measured in normal newborns, and retrospectively in newborns with established disorders, using liquid chromatography tandem mass spectrometry (LC-MS/MS) with stable isotope-labelled internal standards for homocysteine. Analytes were separated using reverse phase chromatography with a total run time of 3 min. The method was linear over the range of 10-100 μmol/L of tHcy and showed excellent precision; intra-batch CV was 4% and inter-batch precision 6.5%. Comparison of 59 plasma values with DBS for tHcy taken at the same time showed excellent correlation, (r (2)>0.97). The reference range for current neonatal samples was 5.4-10.7 μmol/L (n=99), and for the stored neonatal samples (stored dry, sealed in plastic at room temperature for 10 years) was 1.7-5.5 μmol/L, (n=50), both being normally distributed. The clinical utility of this method was checked by retrospective analysis of stored NBS samples from patients with different forms of homocystinuria, including four different remethylating disorders. All had clear elevations of tHcy.
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http://dx.doi.org/10.1007/8904_2011_109DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3509913PMC
February 2013

A pilot study of the effect of (e, e)-2, 4-undecadienal on the offensive odour of trimethylamine.

JIMD Rep 2013 23;8:11-5. Epub 2012 May 23.

Genetic Metabolic Disorders Service, Western Sydney Genetics Program, Children's Hospital at Westmead, Sydney, Australia.

Introduction: Trimethylaminuria is a malodour syndrome caused by a functional defect of flavin-containing monoxygenase 3 (FMO3), resulting in accumulation of trimethylamine in body secretions. Recently, (E, E)-2, 4-undecadienal has been shown to deodorize the offensive odour of cooked porcine intestines (chitlins). We tested the deodorizing effect of commercially available (E, E)-2, 4-undecadienal on the odour of trimethylamine (TMA) in solution.

Study Participants: Eleven volunteers among staff of the Children's Hospital at Westmead, Sydney, Australia.

Methods: This was a study in three stages. In the first stage,12 volunteers sniffed and graded a commercially available trimethylamine at variable concentrations (12.5-10,000 μmol/L). Those who could smell trimethylamine scored the odour of mixtures of (E, E)-2, 4-undecadienal and trimethylamine. Finally, the odour of trimethylamine was graded with increasing concentrations of (E, E)-2, 4-undecadienal (0.1-100 ppm).

Results: All except one could detect the characteristic trimethylamine odour at varying concentrations (12.5-10,000 μmol/L) and reported the odour as offensive and fish like. There was a dose response effect of the ability of (E, E)-2, 4-undecadienal to deodorize the odour of trimethylamine. (E, E)-2, 4-undecadienal at 10 ppm appeared to deodorize the odour of trimethylamine at 1,000 μmol/L without making the former's odour obvious.

Conclusions: We have demonstrated that (E, E)-2, 4-undecadienal has a deodorizing effect on the offensive odour of trimethylamine in solution. The mechanism of action for this effect and potential for treatment of affected individuals needs further research.
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http://dx.doi.org/10.1007/8904_2012_149DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3565655PMC
February 2013

Morphology and molecular phylogeny of Staurojoenina mulleri sp. nov. (Trichonymphida, Parabasalia) from the hindgut of the kalotermitid Neotermes jouteli.

J Eukaryot Microbiol 2013 Mar-Apr;60(2):203-13. Epub 2013 Feb 11.

Canadian Institute for Advanced Research, Department of Botany, University of British Columbia, Vancouver, BC V6T 1Z4, Canada.

Staurojoenina is a large and structurally complex genus of hypermastigont parabasalians found in the hindgut of lower termites. Although several species of Staurojoenina have been described worldwide, all Staurojoenina observed to date in different species of North American termites have been treated as the same species, S. assimilis. Here, we characterize Staurojoenina from the North American termite Neotermes jouteli using light microscopy, scanning electron microscopy, and phylogenetic analysis of small subunit ribosomal RNA, and compare it with S. assimilis from its type host, Incisitermes minor. The basic morphological characteristics of the N. jouteli symbiont, including its abundant bacterial epibionts, are similar as far as they may be compared with existing data from S. assimilis, although not consistently identical. In contrast, we find that they are extremely distantly related at the molecular level, sharing a pairwise similarity of SSU rRNA genes comparable to that seen between different genera or even families of other parabasalians. Based on their evolutionary distance and habitat in different termite genera, we consider the N. jouteli Staurojoenina to be distinct from S. assimilis, and describe a new species, Staurojoenina mulleri, in honor of the pioneering parabasalian researcher, Miklos Muller.
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http://dx.doi.org/10.1111/jeu.12024DOI Listing
August 2013

Direct chemical evidence for sphingolipid domains in the plasma membranes of fibroblasts.

Proc Natl Acad Sci U S A 2013 Feb 28;110(8):E613-22. Epub 2013 Jan 28.

School of Chemical Sciences, University of Illinois, Urbana, IL 61801, USA.

Sphingolipids play important roles in plasma membrane structure and cell signaling. However, their lateral distribution in the plasma membrane is poorly understood. Here we quantitatively analyzed the sphingolipid organization on the entire dorsal surface of intact cells by mapping the distribution of (15)N-enriched ions from metabolically labeled (15)N-sphingolipids in the plasma membrane, using high-resolution imaging mass spectrometry. Many types of control experiments (internal, positive, negative, and fixation temperature), along with parallel experiments involving the imaging of fluorescent sphingolipids--both in living cells and during fixation of living cells--exclude potential artifacts. Micrometer-scale sphingolipid patches consisting of numerous (15)N-sphingolipid microdomains with mean diameters of ∼200 nm are always present in the plasma membrane. Depletion of 30% of the cellular cholesterol did not eliminate the sphingolipid domains, but did reduce their abundance and long-range organization in the plasma membrane. In contrast, disruption of the cytoskeleton eliminated the sphingolipid domains. These results indicate that these sphingolipid assemblages are not lipid rafts and are instead a distinctly different type of sphingolipid-enriched plasma membrane domain that depends upon cortical actin.
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http://dx.doi.org/10.1073/pnas.1216585110DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3581929PMC
February 2013

Human Variome Project country nodes: documenting genetic information within a country.

Hum Mutat 2012 Nov 18;33(11):1513-9. Epub 2012 Jul 18.

Department of Pharmacy, School of Health Sciences, University of Patras, Patras, Greece.

The Human Variome Project (http://www.humanvariomeproject.org) is an international effort aiming to systematically collect and share information on all human genetic variation. The two main pillars of this effort are gene/disease-specific databases and a network of Human Variome Project Country Nodes. The latter are nationwide efforts to document the genomic variation reported within a specific population. The development and successful operation of the Human Variome Project Country Nodes are of utmost importance to the success of Human Variome Project's aims and goals because they not only allow the genetic burden of disease to be quantified in different countries, but also provide diagnosticians and researchers access to an up-to-date resource that will assist them in their daily clinical practice and biomedical research, respectively. Here, we report the discussions and recommendations that resulted from the inaugural meeting of the International Confederation of Countries Advisory Council, held on 12th December 2011, during the 2011 Human Variome Project Beijing Meeting. We discuss the steps necessary to maximize the impact of the Country Node effort for developing regional and country-specific clinical genetics resources and summarize a few well-coordinated genetic data collection initiatives that would serve as paradigms for similar projects.
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http://dx.doi.org/10.1002/humu.22147DOI Listing
November 2012

Fluorinated colloidal gold immunolabels for imaging select proteins in parallel with lipids using high-resolution secondary ion mass spectrometry.

Bioconjug Chem 2012 Mar 15;23(3):450-60. Epub 2012 Feb 15.

Department of Chemistry, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, USA.

The local abundance of specific lipid species near a membrane protein is hypothesized to influence the protein's activity. The ability to simultaneously image the distributions of specific protein and lipid species in the cell membrane would facilitate testing these hypotheses. Recent advances in imaging the distribution of cell membrane lipids with mass spectrometry have created the desire for membrane protein probes that can be simultaneously imaged with isotope labeled lipids. Such probes would enable conclusive tests to determine whether specific proteins colocalize with particular lipid species. Here, we describe the development of fluorine-functionalized colloidal gold immunolabels that facilitate the detection and imaging of specific proteins in parallel with lipids in the plasma membrane using high-resolution SIMS performed with a NanoSIMS. First, we developed a method to functionalize colloidal gold nanoparticles with a partially fluorinated mixed monolayer that permitted NanoSIMS detection and rendered the functionalized nanoparticles dispersible in aqueous buffer. Then, to allow for selective protein labeling, we attached the fluorinated colloidal gold nanoparticles to the nonbinding portion of antibodies. By combining these functionalized immunolabels with metabolic incorporation of stable isotopes, we demonstrate that influenza hemagglutinin and cellular lipids can be imaged in parallel using NanoSIMS. These labels enable a general approach to simultaneously imaging specific proteins and lipids with high sensitivity and lateral resolution, which may be used to evaluate predictions of protein colocalization with specific lipid species.
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http://dx.doi.org/10.1021/bc200482zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3951754PMC
March 2012

Symbiosis, morphology, and phylogeny of Hoplonymphidae (Parabasalia) of the wood-feeding roach Cryptocercus punctulatus.

J Eukaryot Microbiol 2011 Sep-Oct;58(5):426-36. Epub 2011 Jun 23.

Department of Botany, University of British Columbia, 3529-6270 University Boulevard, Vancouver, BC, Canada V6T 1Z4.

Anaerobic cellulolytic flagellate protists of the hindguts of lower termites and the wood-feeding cockroach Cryptocercus are essential to their host's ability to digest lignocellulose. Many have bacteria associated with their surfaces and within cytoplasmic vesicles-likely important symbioses as suggested by molecular and other data. Some of the most striking examples of these symbioses are in the parabasalid family Hoplonymphidae, but little or no data exist on the structural aspects of their symbioses, their relationships with bacteria through different life-cycle stages, or their diversity and phylogenetic relationships in Cryptocercus. We investigated these areas in the hoplonymphid genera Barbulanympha and Urinympha from Cryptocercus punctulatus using light and electron microscopy, and analysis of small subunit rRNA. Microscopy reveals variation in density of bacterial surface symbionts related to life-cycle stage, a glyococalyx possibly important in bacterial adhesion and/or metabolite exchange, and putative viruses associated with bacterial surface symbionts. Patterning of surface bacteria suggests protists emerging from the resistant (dormant) stage are colonized by a small population of bacterial cells, which then divide to cover their surface. Additionally, cytoplasmic protrusions from the protist are covered by bacteria. Phylogenetic analysis rejects the monophyly of Hoplonymphidae, suggesting multiple origins or losses of these bacterial symbioses.
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http://dx.doi.org/10.1111/j.1550-7408.2011.00564.xDOI Listing
January 2012

Induction and prevention of severe hyperammonemia in the spfash mouse model of ornithine transcarbamylase deficiency using shRNA and rAAV-mediated gene delivery.

Mol Ther 2011 May 8;19(5):854-9. Epub 2011 Mar 8.

Gene Therapy Research Unit, Children's Medical Research Institute and The Children's Hospital at Westmead, Wentworthville, New South Wales, Australia.

Urea cycle defects presenting early in life with hyperammonemia remain difficult to treat and commonly necessitate liver transplantation. Gene therapy has the potential to prevent hyperammonemic episodes while awaiting liver transplantation, and possibly also to avert the need for transplantation altogether. Ornithine transcarbamylase (OTC) deficiency, the most prevalent urea cycle disorder, provides an ideal model for the development of liver-targeted gene therapy. While we and others have successfully cured the spf(ash) mouse model of OTC deficiency using adeno-associated virus (AAV) vectors, a major limitation of this model is the presence of residual OTC enzymatic activity which confers a mild phenotype without clinically significant hyperammonemia. To better model severe disease we devised a strategy involving AAV2/8-mediated delivery of a short hairpin RNA (shRNA) to specifically knockdown residual endogenous OTC messenger RNA (mRNA). This strategy proved highly successful with vector-treated mice developing severe hyperammonemia and associated neurological impairment. Using this system, we showed that the dose of an AAV rescue construct encoding the murine OTC (mOTC) cDNA required to prevent hyperammonemia is fivefold lower than that required to control orotic aciduria. This result is favorable for clinical translation as it indicates that the threshold for therapeutic benefit is likely to be lower than indicated by earlier studies.
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http://dx.doi.org/10.1038/mt.2011.32DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3098641PMC
May 2011

Molecular and morphological analysis of the family Calonymphidae with a description of Calonympha chia sp. nov., Snyderella kirbyi sp. nov., Snyderella swezyae sp. nov. and Snyderella yamini sp. nov.

Int J Syst Evol Microbiol 2011 Oct 26;61(Pt 10):2547-2558. Epub 2010 Nov 26.

Department of Botany, University of British Columbia, 3529-6270 University Boulevard, Vancouver, BC V6T 1Z4, Canada.

Calonymphids are a group of multinucleate, multiflagellate protists belonging to the order Cristamonadida (Parabasalia) that are found exclusively in the hindgut of termites from the family Kalotermitidae. Despite their impressive morphological complexity and diversity, few species have been formally described and fewer still have been characterized at the molecular level. In this study, four novel species of calonymphids were isolated and characterized: Calonympha chia and Snyderella yamini spp. nov., from Neotermes castaneus and Calcaritermes nearcticus from Florida, USA, and Snyderella kirbyi and Snyderella swezyae, spp. nov., from Calcaritermes nigriceps and Cryptotermes cylindroceps from Colombia. Each of these species was distinguished from its congeners by residing in a distinct host and by differences at the molecular level. Phylogenetic analyses of small subunit (SSU) rDNA indicated that the genera Calonympha and Stephanonympha were probably not monophyletic, though the genus Snyderella, previously only represented by one sequence in molecular analyses, appeared with these new data to be monophyletic. This was in keeping with the traditional evolutionary view of the group in which the morphology of the genus Snyderella is considered to be derived, while that of the genus Stephanonympha is ancestral and therefore probably plesiomorphic.
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http://dx.doi.org/10.1099/ijs.0.028480-0DOI Listing
October 2011

Maternal riboflavin deficiency, resulting in transient neonatal-onset glutaric aciduria Type 2, is caused by a microdeletion in the riboflavin transporter gene GPR172B.

Hum Mutat 2011 Jan;32(1):E1976-84

Children's Hospital at Westmead, Sydney, Australia.

Riboflavin, or vitamin B2, is a precursor to flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN) molecules, required in biological oxidation-reduction reactions. We previously reported a case of a newborn female who had clinical and biochemical features of multiple acyl-CoA dehydrogenation deficiency (MADD), which was corrected by riboflavin supplementation. The mother was then found to be persistently riboflavin deficient, suggesting that a possible genetic defect in riboflavin transport in the mother was the cause of the transient MADD seen in the infant. Two recently-identified riboflavin transporters G protein-coupled receptor 172B (GPR172B or RFT1) and riboflavin transporter 2 (C20orf54 or RFT2) were screened for mutations. Two missense sequence variations, c.209A>G [p.Q70R] and c.886G>A [p.V296M] were found in GPR172B. In vitro functional studies of both missense variations showed that riboflavin transport was unaffected by these variations. Quantitative real-time PCR revealed a de novo deletion in GPR172B spanning exons 2 and 3 in one allele from the mother. We postulate that haploinsufficiency of this riboflavin transporter causes mild riboflavin deficiency, and when coupled with nutritional riboflavin deficiency in pregnancy, resulted in the transient riboflavin-responsive disease seen in her newborn infant. This is the first report of a genetic defect in riboflavin transport in humans.
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http://dx.doi.org/10.1002/humu.21399DOI Listing
January 2011

Perinatal hypophosphatasia presenting as neonatal epileptic encephalopathy with abnormal neurotransmitter metabolism secondary to reduced co-factor pyridoxal-5'-phosphate availability.

J Inherit Metab Dis 2010 Dec 5;33 Suppl 3:S25-33. Epub 2010 Jan 5.

Genetic Metabolic Disorders Service, The Children's Hospital at Westmead, Sydney, Australia.

We describe two neonates presenting with perinatal hypophosphatasia and severe epileptic encephalopathy resulting in death. Both had increased levels of urinary vanillactate, indicating functional deficiency of aromatic amino acid decarboxylase, a pyridoxal-5-phosphate (PLP)-dependent enzyme required for dopamine and serotonin biosynthesis. Clinical findings and results of subsequent metabolic investigations were consistent with secondary pyridoxine-deficient encephalopathy. These patients highlight the importance of tissue non-specific alkaline phosphatase in the neuronal PLP-dependent metabolism of neurotransmitters. In addition, the disturbance of PLP metabolism appears to underlie the predominant neurological presentation in our patients. We recommend the measurement of serum alkaline phosphatase (ALP) during the assessment of perinatal seizures.
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http://dx.doi.org/10.1007/s10545-009-9012-yDOI Listing
December 2010

The inadequacy of morphology for species and genus delineation in microbial eukaryotes: an example from the parabasalian termite symbiont coronympha.

PLoS One 2009 Aug 11;4(8):e6577. Epub 2009 Aug 11.

Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada.

Background: For the majority of microbial eukaryotes (protists, algae), there is no clearly superior species concept that is consistently applied. In the absence of a practical biological species concept, most species and genus level delineations have historically been based on morphology, which may lead to an underestimate of the diversity of microbial eukaryotes. Indeed, a growing body of molecular evidence, such as barcoding surveys, is beginning to support the conclusion that significant cryptic species diversity exists. This underestimate of diversity appears to be due to a combination of using morphology as the sole basis for assessing diversity and our inability to culture the vast majority of microbial life. Here we have used molecular markers to assess the species delineations in two related but morphologically distinct genera of uncultivated symbionts found in the hindgut of termites.

Methodology/principal Findings: Using single-cell isolation and environmental PCR, we have used a barcoding approach to characterize the diversity of Coronympha and Metacoronympha symbionts in four species of Incisitermes termites, which were also examined using scanning electron microscopy and light microcopy. Despite the fact that these genera are significantly different in morphological complexity and structural organisation, we find they are two life history stages of the same species. At the same time, we show that the symbionts from different termite hosts show an equal or greater level of sequence diversity than do the hosts, despite the fact that the symbionts are all classified as one species.

Conclusions/significance: The morphological information used to describe the diversity of these microbial symbionts is misleading at both the genus and species levels, and led to an underestimate of species level diversity as well as an overestimate of genus level diversity. The genus 'Metacoronympha' is invalid and appears to be a life history stage of Coronympha, while the single recognized species of Coronympha octonaria inhabiting these four termites is better described as four distinct species.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0006577PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2719052PMC
August 2009

Phylogenetic position and morphology of spirotrichosomidae (parabasalia): new evidence from Leptospironympha of Cryptocercus punctulatus.

Protist 2010 Jan 6;161(1):122-32. Epub 2009 Aug 6.

Canadian Institute for Advanced Research, Botany Department, University of British Columbia, 3529-6270 University Boulevard, Vancouver, BC, Canada V6T 1Z4.

Parabasalia are a large, diverse clade of anaerobic flagellates, many of which inhabit the guts of wood-feeding insects. Because most are uncultivable, molecular data representing the true diversity of Parabasalia only became possible with the application of single-cell techniques, but in the last decade molecular data have accumulated rapidly. Within the Trichonymphida, the most diverse lineage of hypermastigote parabasalids, molecular data are now available from five of the six families, however, one family, the Spirotrichosomidae, has not been sampled at the molecular level, and is very little studied with electron microscopy. Here we examine a representative of Spirotrichosomidae--Leptospironympha of the wood-feeding cockroach Cryptocercus punctulatus--with scanning and transmission electron microscopy, and analyze its small subunit rRNA gene to infer its phylogenetic position. Phylogenetic analyses place Leptospironympha as sister to a clade comprising Eucomonymphidae and Teranymphidae with moderate support. Examination with scanning and transmission electron microscopy reveals new classes of previously undetected symbiotic surface bacteria, a glycocalyx, granular particles on flagella, and putative phagocytosed bacteria. The range of flagellar patterns in Spirotrichosomidae is quite wide, and the possibility that some members may be more closely related to Eucomonymphidae or Teranymphidae is addressed.
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http://dx.doi.org/10.1016/j.protis.2009.06.003DOI Listing
January 2010

Expanded newborn screening: outcome in screened and unscreened patients at age 6 years.

Pediatrics 2009 Aug 20;124(2):e241-8. Epub 2009 Jul 20.

Department of Biochemical Genetics, Children's Hospital at Westmead, Sydney, Australia.

Objective: Tandem mass spectrometry is widely applied to routine newborn screening but there are no long-term studies of outcome. We studied the clinical outcome at six years of age in Australia.

Methods: In a cohort study, we analyzed the outcome at 6 years for patients detected by screening or by clinical diagnosis among >2 million infants born from 1994 to 1998 (1,017,800, all unscreened) and 1998 to 2002 (461,500 screened, 533,400 unscreened) recording intellectual and physical condition, school placement, other medical problems, growth, treatment, diet, and hospital admissions. Results were analyzed separately for medium-chain acyl-CoA dehydrogenase deficiency (MCADD) and other disorders, and grouped patients as those who presented clinically or died in the first 5 days of life; patients presented later or diagnosed by screening, and those with substantially benign disorders.

Results: Inborn errors, excluding phenylketonuria, were diagnosed in 116 of 1,551,200 unscreened infants (7.5/100,000 births) and 70 of 461,500 screened infants (15.2/100,000 births). Excluding MCADD, 21 unscreened patients with metabolic disorders diagnosed after 5 days of life died or had a significant intellectual or physical handicap (1.35/100,000 population) compared with 2 of the screened cohort (0.43/100,000; odds ratio: 3.1 [95% CI: 0.73-13.32]). Considering the likely morbidity or mortality among the expected number of never-diagnosed unscreened patients, there would be a significant difference. Growth distribution was normal in all cohorts.

Conclusion: Screening by tandem mass spectrometry provides a better outcome for patients at 6 years of age, with fewer deaths and fewer clinically significant disabilities.
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http://dx.doi.org/10.1542/peds.2008-0586DOI Listing
August 2009

Morphology, phylogeny, and diversity of Trichonympha (Parabasalia: Hypermastigida) of the wood-feeding cockroach Cryptocercus punctulatus.

J Eukaryot Microbiol 2009 Jul-Aug;56(4):305-13

Canadian Institute for Advanced Research, Botany Department, University of British Columbia, Vancouver, BC, Canada.

Trichonympha is one of the most complex and visually striking of the hypermastigote parabasalids-a group of anaerobic flagellates found exclusively in hindguts of lower termites and the wood-feeding cockroach Cryptocercus-but it is one of only two genera common to both groups of insects. We investigated Trichonympha of Cryptocercus using light and electron microscopy (scanning and transmission), as well as molecular phylogeny, to gain a better understanding of its morphology, diversity, and evolution. Microscopy reveals numerous new features, such as previously undetected bacterial surface symbionts, adhesion of post-rostral flagella, and a distinctive frilled operculum. We also sequenced small subunit rRNA gene from manually isolated species, and carried out an environmental polymerase chain reaction (PCR) survey of Trichonympha diversity, all of which strongly supports monophyly of Trichonympha from Cryptocercus to the exclusion of those sampled from termites. Bayesian and distance methods support a relationship between Trichonympha species from termites and Cryptocercus, although likelihood analysis allies the latter with Eucomonymphidae. A monophyletic Trichonympha is of great interest because recent evidence supports a sister relationship between Cryptocercus and termites, suggesting Trichonympha predates the Cryptocercus-termite divergence. The monophyly of symbiotic bacteria of Trichonympha raises the intriguing possibility of three-way co-speciation among bacteria, Trichonympha, and insect hosts.
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http://dx.doi.org/10.1111/j.1550-7408.2009.00406.xDOI Listing
September 2009
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