Publications by authors named "Mohammad A Hussain"

14 Publications

  • Page 1 of 1

Effects of electrically conductive nano-biomaterials on regulating cardiomyocyte behavior for cardiac repair and regeneration.

Acta Biomater 2021 Nov 21. Epub 2021 Nov 21.

Division of Engineering in Medicine, Department of Medicine, Harvard Medical School, Brigham and Women's Hospital, Cambridge, MA 02139, USA. Electronic address:

Myocardial infarction (MI) represents one of the most prevalent cardiovascular diseases, with a highly relevant and impactful role in public health. Despite the therapeutic advances of the last decades, MI still begets extensive death rates around the world. The pathophysiology of the disease correlates with cardiomyocyte necrosis, caused by an imbalance in the demand of oxygen to cardiac tissues, resulting from obstruction of the coronary flow. To alleviate the severe effects of MI, the use of various biomaterials exhibit vast potential in cardiac repair and regeneration, acting as native extracellular matrices. These hydrogels have been combined with nano sized or functional materials which possess unique electrical, mechanical, and topographical properties that play important roles in regulating phenotypes and the contractile function of cardiomyocytes even in adverse microenvironments. These nano-biomaterials' differential properties have led to substantial healing on in vivo cardiac injury models by promoting fibrotic scar reduction, hemodynamic function preservation, and benign cardiac remodeling. In this review, we discuss the interplay of the unique physical properties of electrically conductive nano-biomaterials, are able to manipulate the phenotypes and the electrophysiological behavior of cardiomyocytes in vitro, and can enhance heart regeneration in vivo. Consequently, the understanding of the decisive roles of the nano-biomaterials discussed in this review could be useful for designing novel nano-biomaterials in future research for cardiac tissue engineering and regeneration. STATEMENT OF SIGNIFICANCE: This study introduced and deciphered the understanding of the role of multimodal cues in recent advances of electrically conductive nano-biomaterials on cardiac tissue engineering. Compared with other review papers, which mainly describe these studies based on various types of electrically conductive nano-biomaterials, in this review paper we mainly discussed the interplay of the unique physical properties (electrical conductivity, mechanical properties, and topography) of electrically conductive nano-biomaterials, which would allow them to manipulate phenotypes and the electrophysiological behaviour of cardiomyocytes in vitro and to enhance heart regeneration in vivo. Consequently, understanding the decisive roles of the nano-biomaterials discussed in the review could help design novel nano-biomaterials in future research for cardiac tissue engineering and regeneration.
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http://dx.doi.org/10.1016/j.actbio.2021.11.022DOI Listing
November 2021

Work productivity trajectories of Australians living with multiple sclerosis: A group-based modelling approach.

Mult Scler Relat Disord 2021 Sep 10;54:103131. Epub 2021 Jul 10.

Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS, Australia.

Background: Studies have documented reduced work capacity and work productivity loss in multiple sclerosis (MS). Little is known about the longitudinal trajectories of work productivity in MS.

Objectives: To examine trajectories of work productivity in people living with multiple sclerosis (PwMS) and the factors associated with the trajectories.

Methods: Study participants were employed participants of the Australian MS Longitudinal Study (AMSLS) followed from 2015 to 2019 with at least two repeated measures (n=2121). We used group-based trajectory modelling to identify unique work productivity trajectories in PwMS.

Results: We identified three distinct trajectories of work productivity: 'moderately reduced' (17.0% of participants) with a mean work productivity level of 47.6% in 2015 (slope -0.97% per year (p= 0.22)), 'mildly reduced' (46.7%) with a mean work productivity of 86.3% in 2015 (slope 0.70% per year (p=0.12)), and 'full' (36.3%) with a mean work productivity of 99.7% in 2015 (slope 0.29% per year (p= 0.30)). Higher education level, higher disability, and higher MS symptom severity are associated with increased probability of being in a worse work productivity trajectory.

Conclusion: We identified three distinct work productivity trajectories in PwMS which were stable over time and differentiated by their baseline level of work productivity.
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http://dx.doi.org/10.1016/j.msard.2021.103131DOI Listing
September 2021

Changes in multiple sclerosis symptoms are associated with changes in work productivity of people living with multiple sclerosis.

Mult Scler 2021 Nov 16;27(13):2093-2102. Epub 2021 Feb 16.

Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS, Australia.

Background: While employment rates have increased in people with multiple sclerosis (PwMS), little is known about the longitudinal trends of work productivity.

Objective: To describe the longitudinal patterns of work productivity and examine the factors associated with annual change of work productivity of PwMS.

Methods: Study participants were employed participants of the Australian MS Longitudinal Study (AMSLS) followed from 2015 to 2019 with at least two repeated measures ( = 2121). We used linear mixed models to examine if the within-individual variations in MS symptoms are associated with changes in work productivity.

Results: The mean annual change in work productivity between 2015 and 2019 was -0.23% ( = 18.68%). Not the actual severity of symptoms but rather the changes in severity of symptoms that are associated with change in work productivity in the same year. In a multivariable model, every unit increase in mean annual change in 'pain and sensory symptoms', 'feelings of anxiety and depression', and 'fatigue and cognitive symptoms' were independently associated with 2.43%, 1.55% and 1.01% annual reductions in work productivity, respectively.

Conclusion: Individual changes in work productivity are largely driven by the changes in symptom severity rather than the absolute severity. Stabilising/improving MS symptoms might improve work productivity.
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http://dx.doi.org/10.1177/1352458521994557DOI Listing
November 2021

Complex Structural Interventions: The Role of Computed Tomography, Fluoroscopy, and Fusion Imaging.

Methodist Debakey Cardiovasc J 2017 Jul-Sep;13(3):98-105

HOUSTON METHODIST HOSPITAL, HOUSTON, TEXAS.

Noninvasive cardiac imaging has played a critical part in the evaluation, monitoring, and follow-up of structural heart disease. This review will highlight the role of cardiac computed tomography, fluoroscopy, and fusion imaging in guiding transcatheter aortic valve replacement and other percutaneous strategies used to diagnose and treat complex structural heart complications.
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http://dx.doi.org/10.14797/mdcj-13-3-98DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5935210PMC
August 2018

Multipolar electrode spline embolization.

HeartRhythm Case Rep 2018 Jan 13;4(1):34-35. Epub 2017 Nov 13.

Methodist DeBakey Heart and Vascular Center and Houston Methodist Hospital Research Institute, Houston Methodist Hospital, Houston, Texas.

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http://dx.doi.org/10.1016/j.hrcr.2017.10.014DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5775444PMC
January 2018

Mass drug administration for lymphatic filariasis elimination in a coastal state of India: a study on barriers to coverage and compliance.

Infect Dis Poverty 2014 1;3:31. Epub 2014 Sep 1.

Public Health Foundation of India, Indian Institute of Public Health, Bhubaneswar, Odisha, India.

Background: Lymphatic filariasis is targeted for elimination in India through mass drug administration (MDA) with diethylcarbamazine (DEC) combined with albendazole (ABZ). For the strategy to be effective, >65% of those living in endemic areas must be covered by and compliant to MDA. Post the MDA 2011 campaign in the endemic district of Odisha, we conducted a survey to assess: (i) the filariasis knowledge in the community, (ii) the coverage and compliance of MDA from the community perspective, and (iii) factors affecting compliance, as well as the operational issues involved in carrying out MDA activities from the drug distributor's perspective.

Methods: A sample of 691 participants - both male and female, aged two years or above - were selected through multistage stratified sampling and interviewed using a semi-structured questionnaire. Additionally, drug distributors and the medical officers in charge of the MDA were also interviewed to understand some of the operational issues encountered during MDA.

Results: Ninety-nine percent of the study participants received DEC and ABZ tablets during MDA, of which only just above a quarter actually consumed the drugs. The cause of non-compliance was mostly due to fear of side effects, lack of awareness of the benefits of MDA, and non-attendance of health staff in the villages. Lack of adequate training of drug distributors and poor health communication activities before the MDA campaign commenced and the absence of follow-up by health workers following MDA were a few of the operational difficulties encountered during the MDA campaign.

Conclusion: Currently MDA is restricted to the distribution of drugs only and the key issues of implementation in compliance, health education, managing side effects, and logistics are not given enough attention. It is therefore essential to address the issues linked to low compliance to make the program more efficient and achieve the goal of filariasis elimination.
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http://dx.doi.org/10.1186/2049-9957-3-31DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4166397PMC
September 2014

Neonatal care practices in a tribal community of Odisha, India: a cultural perspective.

J Trop Pediatr 2014 Jun 10;60(3):238-44. Epub 2014 Feb 10.

Division of Epidemiology & Biostatistics, School of Population Health, The University of Queensland Herston, Brisbane 4006, Australia.

Neonatal care practices have been shown to vary across tribal communities. This cross-sectional study was conducted in tribal block in Nabarangpur district of Odisha, India, to measure perinatal and antenatal practices by qualitative inquiries of 55 mothers who had babies aged <60 days and from 11 traditional birth attendants. Reasons for home deliveries were cited as easy availability of traditional birth attendants and family preferences. Application of indigenously made substances on umbilical stump and skin of the baby, bathing baby immediately after birth, late initiation of breast-feeding and 'Budu practices' were common. Cultural issues, decision of family members and traditional beliefs still play a crucial role in shaping neonatal care practice in tribal communities. Awareness on child care, ethnographic understanding of health-seeking behavior of tribal community and mobilization of community by health workers can be useful in improving health status of mothers and newborn babies in tribal population.
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http://dx.doi.org/10.1093/tropej/fmu005DOI Listing
June 2014

Public health system readiness to treat malaria in Odisha State of India.

Malar J 2013 Oct 2;12:351. Epub 2013 Oct 2.

Indian Institute of Public Health, Bhubaneswar, Odisha, India.

Background: Early diagnosis and prompt treatment is a cornerstone of malaria control. In India, artemisinin combination therapy (ACT) became the first-line treatment for falciparum malaria and rapid diagnostic test (RDTs) kits were recommended for use at the grass-root level in the new malaria treatment policy (2010). Odisha State contributes about one-fourth of the total Indian malaria burden and 40% of falciparum infection. The present study assessed the health system readiness to deploy RDTs and ACT for malaria control across the State.

Methods: Data collection was carried out from February to July 2012. Five of Odisha's 30 districts were selected through stratified random sampling, with stratification based on the phased roll-out of ACT and RDT. Two administrative 'blocks' were selected randomly in each district and data collected through health facility, auxiliary nurse midwives (ANMs) and accredited social health activist (ASHAs) assessments. Key informant interviews were conducted with individuals involved in the implementation of the malaria control programme.

Results: Of the 220 ANMs interviewed, 51.4% had been trained in malaria case management, including the use of ACT and RDT. A high proportion of ANM (80%) and AHSA (77%) had the necessary level of knowledge to be able to use RDT for malaria diagnosis. The proportion of ASHAs trained on malaria case management was 88.9% (209/235). However, 71% of ANM and 55% of ASHAs usually referred falciparum-positive patients to the health facility for treatment, the major reason for referral being the non-availability of drugs at the ANM and ASHA level.

Conclusion: The relatively high level of knowledge about how to diagnose and treat malaria at the grass-root level was undermined by the poor availability of RDTs, ACT and primaquine tablets. This was associated with an unnecessarily high referral rate and potential delays in the treatment of this potentially life-threatening infection. Improvements in the supply chain for RDTs and ACT could dramatically enhance the effectiveness of malaria control in Odisha.
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http://dx.doi.org/10.1186/1475-2875-12-351DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3850888PMC
October 2013

Malaria control in India: has sub-optimal rationing of effective interventions compromised programme efficiency?

WHO South East Asia J Public Health 2012 Apr-Jun;1(2):128-132

Indian Institute of Public Health, Delhi; Public Health Foundation of India, New Delhi, India.

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http://dx.doi.org/10.4103/2224-3151.206925DOI Listing
June 2017

Investigation of nano-mechanical properties of annulus fibrosus using atomic force microscopy.

Micron 2008 Oct 14;39(7):1008-19. Epub 2007 Sep 14.

Department of Bioengineering, University of Illinois at Chicago, Science and Engineering Offices (SEO), room 218, 815 S. Morgan Street (m/c 063), Chicago, IL 60607-7052, USA.

We describe the use of atomic force microscopy (AFM) to investigate the nanomechanical properties of annulus fibrosus (AF)-the outer fibrous layer of an intervertebral disc (IVD) encapsulating the inner jelly-like mass known as the nucleus pulposus (NP). Disk disease, degenerated discs, slipped discs, and herniated discs are common terms often linked to back pain and are caused due to degeneration of IVD. Due to the variations in the structure and biochemical composition of the IVD, studies of macromechanical properties in the motion segment or AF may lack all significant nanomechanical responses or behaviors. Existing studies do not report the micro or nano level of mechanics of IVD components and whether the nanomechanics of this tissue mimic its macromechanical behavior is not known. Our studies used AFM to investigate the regional micromechanical properties of the AF that have been otherwise difficult due to small sample size of the tissue. Five different zones including peripheral and central were tested mechanically as well as biochemically. Qualitative biochemical staining and quantitative values of nanomechanical properties of different zones are compared and discussed in detail. The results of nanomechanical investigations described in this study not only reveal its mimic at macroscopic level, they represent an important step towards establishing a framework for testing and comparing tissue engineered IVD replacements with native tissues.
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http://dx.doi.org/10.1016/j.micron.2007.08.009DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2615464PMC
October 2008

Cytoskeletal changes of mesenchymal stem cells during differentiation.

ASAIO J 2007 Mar-Apr;53(2):219-28

Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, Illinois, USA.

Mesenchymal stem cells (MSCs) are progenitors for tissues such as bone and cartilage. In this report, the actin cytoskeleton and nanomechanobiology of human mesenchymal stem cells (hMSCs) were studied using fluorescence microscopy and atomic force microscopy (AFM). Human MSCs were differentiated into chondrocytes and osteoblasts as per previous approaches. Cytochalasin D (CytD) was used to temporarily disrupt cytoskeleton in hMSCs, hMSC-chondrocytes (hMSC-Cys) and hMSC-osteoblasts (hMSC-Obs). Fluorescence microscopy revealed a dose-dependent response to CytD. Removal of CytD from the media of cytoskeleton-disrupted cells led to the recovery of the cytoskeletal structures, as confirmed by both fluorescence microscopy and AFM. Force-volume imaging by AFM evaluated the nanomechanics of all three cell types before, during, and after CytD treatment. Cytochalasin D disruption of cytoskeleton had marked effects on hMSCs and hMSC-Cys, in comparison with limited cytoskeleton disruption in hMSC-Obs, as confirmed qualitatively by fluorescence microscopy and quantitatively by AFM. Treatment with CytD resulted in morphology changes of all cell types, with significant decreases in the observed Young's Moduli of hMSCs and hMSC-Cys. These data suggest human mesenchymal stem cells alter their cytoskeletal components during differentiation. Additional studies will address the mechanisms of cytoskeletal changes using biochemical and biophysical methods.
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http://dx.doi.org/10.1097/MAT.0b013e31802deb2dDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4035052PMC
May 2007

AFM imaging of ligand binding to platelet integrin alphaIIbbeta3 receptors reconstituted into planar lipid bilayers.

Langmuir 2005 Jul;21(15):6979-86

Department of Surgery, Biomedical Engineering Institute, Milton S. Hershey Medical Center, Pennsylvania State University, Hershey, Pennsylvania 17033, USA.

The platelet integrin alphaIIbbeta3 plays a key role in platelet adhesion, activation, and aggregation at the subendothelium and at protein-coated synthetic biomaterials. In this study, interactions between alphaIIbbeta3 and both protein and peptide ligands for the receptor were imaged under physiological conditions by high-resolution atomic force microscopy (AFM). To directly image the ligand-receptor interactions, alphaIIbbeta3 receptors were reconstituted into a supported lipid bilayer formed on a mica surface in the AFM fluid cell assembly and subsequently activated with Mn2+. Fibrinogen, the natural protein ligand for the integrin, as well as a nanogold-labeled peptide ligand (an RGD-containing heptamer) were infused into the AFM fluid cell, incubated with the reconstituted and activated receptors, and imaged under buffer. Height images illustrating topographical features showed the integrin reconstituted in the bilayer. Fibrinogen molecules binding to the receptors were easily observed in the height images, with fibrinogen showing its characteristic trinodular structure and occasionally bridging integrin receptors. Fibrinogen was observed to bind to integrins at the D-domain consistent with the location of the gamma-chain dodecapeptide, while fibrinogen bridging integrins bound to receptors on opposite sides of the protein consistent with a 2-fold axis of symmetry. Peptide ligands were not visible in height images; however, phase images that map the mechanical properties detected the nanogold labels and demonstrated the presence of peptide ligands bound to the receptors. The results demonstrate the ability of this high-resolution microscopy technique to directly visualize single ligand/receptor interactions in a dynamic and physiologically relevant environment, and establish a framework for future fundamental studies of single protein/receptor interactions during normal pathological processes as well as biomaterial surface-induced thrombosis.
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http://dx.doi.org/10.1021/la046943hDOI Listing
July 2005

Modulation of bone ingrowth of rabbit femur titanium implants by in vivo axial micromechanical loading.

J Appl Physiol (1985) 2005 May 7;98(5):1922-9. Epub 2005 Jan 7.

Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60612-7211, USA.

Titanium implants commonly used in orthopedics and dentistry integrate into host bone by a complex and coordinated process. Despite increasingly well illustrated molecular healing processes, mechanical modulation of implant bone ingrowth is poorly understood. The objective of the present study was to determine whether micromechanical forces applied axially to titanium implants modulate bone ingrowth surrounding intraosseous titanium implants. We hypothesized that small doses of micromechanical forces delivered daily to the bone-implant interface enhance implant bone ingrowth. Small titanium implants were placed transcortically in the lateral aspect of the proximal femur in 15 New Zealand White rabbits under general anesthesia and allowed to integrate with the surrounding bone for 6 wk. Micromechanical forces at 200 mN and 1 Hz were delivered axially to the right femur implants for 10 min/day over 12 consecutive days, whereas the left femur implants served as controls. The average bone volume 1 mm from mechanically loaded implants (n = 15) was 73 +/- 12%, which was significantly greater than the average bone volume (52 +/- 21%) of the contralateral controls (n = 15) (P < 0.01). The average number of osteoblast-like cells per endocortical bone surface was 55 +/- 8 cells/mm(2) for mechanically loaded implants, which was significantly greater than the contralateral controls (35 +/- 6 cells/mm(2)) (P < 0.01). Dynamic histomorphometry showed a significant increase in mineral apposition rate and bone-formation rate of mechanically stressed implants (3.8 +/- 1.2 microm/day and 2.4 +/- 1.0 microm(3).microm(-2).day(-1), respectively) than contralateral controls (2.2 +/- 0.92 microm/day and 1.2 +/- 0.60 microm(3).microm(-2).day(-1), respectively; P < 0.01). Collectively, these data suggest that micromechanical forces delivered axially on intraosseous titanium implants may have anabolic effects on implant bone ingrowth.
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http://dx.doi.org/10.1152/japplphysiol.01080.2004DOI Listing
May 2005

The platelet integrin alpha(IIb) beta(3) imaged by atomic force microscopy on model surfaces.

Micron 2004 ;35(7):565-73

Department of Surgery, The Biomedical Engineering Institute, The Milton S. Hershey Medical Center, The Pennsylvania State University, Hershey PA 17033, USA.

The platelet membrane receptor alpha(IIb) beta(3) binds to adsorbed protein ligands including fibrinogen, von Willebrand factor and fibronectin, and is critically important in mediating platelet adhesion to damaged subendothelium and to synthetic biomaterial surfaces. This receptor is a member of the integrin family, a highly prevalent class of heterodimeric molecules consisting of a single alpha and beta subunit. In an ongoing effort to understand the mechanisms underlying platelet adhesion events, high-resolution atomic force microscopy (AFM) under dynamic conditions was used to obtain images of alpha(IIb) beta(3) molecules as well as aggregates of the protein. Images of integrin molecules were obtained by tapping mode AFM under aqueous buffer conditions following adsorption on a series of ultrasmooth model surfaces. On a model hydrophobic surface, detergents stabilizing the protein in solution competed for surface adsorption sites. When this detergent was removed from the system, the protein was predominantly seen as aggregates with head groups pointing outward. A limited number of individual integrin molecules were observed, and were found to have dimensions consistent with those reported previously by electron microscopy studies. Integrin molecules showed weak adhesion to the two hydrophilic surfaces used in the study, although formation of a lipid bilayer around surface-adsorbed molecules improved the resolution. At longer time periods, the integrin molecules embedded in this lipid bilayer exhibited sufficient mobility to form molecular aggregates. The structural measurements described in this study not only reveal three-dimensional features of the molecule, they represent an important step towards dynamic adsorption experiments and visualizing the integrin interacting with surface-adsorbed proteins as in biomaterial-induced thrombogenesis.
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http://dx.doi.org/10.1016/j.micron.2004.02.010DOI Listing
September 2004
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