Vaginal morphology and position associated with prolapse recurrence after vaginal surgery: A secondary analysis of the DEMAND study.

OBJECTIVE: To identify vaginal morphology and position factors associated with prolapse recurrence following vaginal surgery. DESIGN: Secondary analysis of magnetic resonance images (MRI) of the Defining Mechanisms of Anterior Vaginal Wall Descent cross-sectional study. SETTING: Eight clinical sites in the US Pelvic Floor Disorders Network. POPULATION OR SAMPLE: Women who underwent vaginal mesh hysteropexy (hysteropexy) with sacrospinous fixation or vaginal hysterectomy with uterosacral ligament suspension (hysterectomy) for uterovaginal prolapse between April 2013 and February 2015. METHODS: The MRI (rest, strain) obtained 30-42 months after surgery, or earlier for participants with recurrence who desired reoperation before 30 months, were analysed. MRI-based prolapse recurrence was defined as prolapse beyond the hymen at strain on MRI. Vaginal segmentations (at rest) were used to create three-dimensional models placed in a morphometry algorithm to quantify and compare vaginal morphology (angulation, dimensions) and position. MAIN OUTCOME MEASURES: Vaginal angulation (upper, lower and upper-lower vaginal angles in the sagittal and coronal plane), dimensions (length, maximum transverse width, surface area, volume) and position (apex, mid-vagina) at rest. RESULTS: Of the 82 women analysed, 12/41 (29%) in the hysteropexy group and 22/41 (54%) in the hysterectomy group had prolapse recurrence. After hysteropexy, women with recurrence had a more laterally deviated upper vagina (p = 0.02) at rest than women with successful surgery. After hysterectomy, women with recurrence had a more inferiorly (lower) positioned vaginal apex (p = 0.01) and mid-vagina (p = 0.01) at rest than women with successful surgery. CONCLUSIONS: Vaginal angulation and position were associated with prolapse recurrence and suggestive of vaginal support mechanisms related to surgical technique and potential unaddressed anatomical defects. Future prospective studies in women before and after prolapse surgery may distinguish these two factors.

Delayed and Interrupted Ventilation with Excess Suctioning after Helping Babies Breathe with Congolese Birth Attendants.

There is a substantial gap in our understanding of resuscitation practices following Helping Babies Breathe (HBB) training. We sought to address this gap through an analysis of observed resuscitations following HBB 2nd edition training in the Democratic Republic of the Congo. This is a secondary analysis of a clinical trial evaluating the effect of resuscitation training and electronic heart rate monitoring on stillbirths. We included in-born, liveborn neonates ≥28 weeks gestation whose resuscitation care was directly observed and documented. For the 2592 births observed, providers dried/stimulated before suctioning in 97% of cases and suctioned before ventilating in 100%. Only 19.7% of newborns not breathing well by 60 s (s) after birth ever received ventilation. Providers initiated ventilation at a median 347 s (>five minutes) after birth; no cases were initiated within the Golden Minute. During 81 resuscitations involving ventilation, stimulation and suction both delayed and interrupted ventilation with a median 132 s spent drying/stimulating and 98 s suctioning. This study demonstrates that HBB-trained providers followed the correct order of resuscitation steps. Providers frequently failed to initiate ventilation. When ventilation was initiated, it was delayed and interrupted by stimulation and suctioning. Innovative strategies targeting early and continuous ventilation are needed to maximize the impact of HBB.

Perceptions and experiences of Congolese midwives implementing a low-cost battery-operated heart rate meter during newborn resuscitation.

Background: 900,000 newborns die from respiratory depression each year; nearly all of these deaths occur in low- and middle-income countries. Deaths from respiratory depression are reduced by evidence-based resuscitation. Electronic heart rate monitoring provides a sensitive indicator of the neonate's status to inform resuscitation care, but is infrequently used in low-resource settings. In a recent trial in the Democratic Republic of the Congo, midwives used a low-cost, battery-operated heart rate meter (NeoBeat) to continuously monitor heart rate during resuscitations. We explored midwives' perceptions of NeoBeat including its utility and barriers and facilitators to use. Methods: After a 20-month intervention in which midwives from three facilities used NeoBeat during resuscitations, we surveyed midwives and conducted focus group discussions (FGDs) regarding the incorporation of NeoBeat into clinical care. FGDs were conducted in Lingala, the native language, then transcribed and translated from Lingala to French to English. We analyzed data by: (1) coding of transcripts using Nvivo, (2) comparison of codes to identify patterns in the data, and (3) grouping of codes into categories by two independent reviewers, with final categories determined by consensus. Results: Each midwife from Facility A used NeoBeat on an estimated 373 newborns, while each midwife at facilities B and C used NeoBeat an average 24 and 47 times, respectively. From FGDs with 30 midwives, we identified five main categories of perceptions and experiences regarding the use of NeoBeat: (1) Providers' initial skepticism evolved into pride and a belief that NeoBeat was essential to resuscitation care, (2) Providers viewed NeoBeat as enabling their resuscitation and increasing their capacity, (3) NeoBeat helped providers identify flaccid newborns as liveborn, leading to hope and the perception of saving of lives, (4) Challenges of use of NeoBeat included cleaning, charging, and insufficient quantity of devices, and (5) Providers desired to continue using the device and to expand its use beyond resuscitation and their own facilities. Conclusion: Midwives perceived that NeoBeat enabled their resuscitation practices, including assisting them in identifying non-breathing newborns as liveborn. Increasing the quantity of devices per facility and developing systems to facilitate cleaning and charging may be critical for scale-up.

Effect of resuscitation training and implementation of continuous electronic heart rate monitoring on identification of stillbirth.

AIM: To evaluate the effect of resuscitation training and continuous electronic heart rate (HR) monitoring of non-breathing newborns on identification of stillbirth. METHODS: We conducted a pre-post interventional trial in three health facilities in the Democratic Republic of the Congo. We collected data on a retrospective control group of newborns that reflected usual resuscitation practice (Epoch 1). In the prospective, interventional group, skilled birth attendants received resuscitation training in Helping Babies Breathe and implemented continuous electronic HR monitoring of non-breathing newborns (Epoch 2). Our primary outcome was the incidence of stillbirth with secondary outcomes of fresh or macerated stillbirth, neonatal death before discharge and perinatal death. Among a subset, we conducted expert review of electronic HR data to estimate misclassification of stillbirth in Epoch 2. We used a generalized estimating equation, adjusted for variation within-facility, to compare risks between EPOCHs. RESULTS: There was no change in total stillbirths following resuscitation training and continuous electronic HR monitoring of non-breathing newborns (aRR 1.15 [0.95, 1.39]). We observed an increased rate of macerated stillbirth (aRR 1.58 [1.24, 2.02]), death before discharge (aRR 3.31 [2.41, 4.54]), and perinatal death (aRR 1.61 [1.38, 1.89]) during the intervention period. In expert review, 20% of newborns with electronic HR data that were classified by SBAs as stillborn were liveborn. CONCLUSION: Resuscitation training and use of continuous electronic HR monitoring did not reduce stillbirths nor eliminate misclassification.

Game-based movement facilitates acute priming effect in stroke.

OBJECTIVE: Cortical priming is an emerging strategy to enhance motor recovery after stroke, however, limited information exists on the neuromodulatory effects of lower limb movement-based priming to facilitate corticomotor excitability after stroke. In this study, we investigated the feasibility and effectiveness of game-based ankle movement priming using the DIG-I-PRIME™ on corticomotor excitability and motor performance in chronic stroke survivors. METHODS: Nineteen stroke survivors participated in a 20-min session of game-based priming. A period of rest served as a control for the priming condition. Transcranial magnetic stimulation (TMS) was used to measure corticomotor excitability of the paretic and non-paretic tibialis anterior (TA) muscle representations. Motor performance was quantified by assessing the accuracy to track a sinusoidal target wave with paretic dorsiflexion and plantarflexion. RESULTS: Ipsilesional corticomotor excitability increased by 25% after game-based movement priming (p = 0.02) while changes were not observed after the control condition. No change in motor performance was noted. CONCLUSION: Game-based ankle movement priming demonstrated a significant acute priming effect on the ipsilesional lower limb M1. These data provide preliminary evidence for the potential benefits of game-based priming to promote functional recovery after stroke.

Institutional deliveries and stillbirth and neonatal mortality in the Global Network's Maternal and Newborn Health Registry.

BACKGROUND: Few studies have shown how the move toward institutional delivery in low and middle-income countries (LMIC) impacts stillbirth and newborn mortality. OBJECTIVES: The study evaluated trends in institutional delivery in research sites in Belagavi and Nagpur India, Guatemala, Kenya, Pakistan, and Zambia from 2010 to 2018 and compared them to changes in the rates of neonatal mortality and stillbirth. METHODS: We analyzed data from a nine-year interval captured in the Global Network (GN) Maternal Newborn Health Registry (MNHR). Mortality rates were estimated from generalized estimating equations controlling for within-cluster correlation. Cluster-level analyses were performed to assess the association between institutional delivery and mortality rates. RESULTS: From 2010 to 2018, a total of 413,377 deliveries in 80 clusters across 6 sites in 5 countries were included in these analyses. An increase in the proportion of institutional deliveries occurred in all sites, with a range in 2018 from 57.7 to 99.8%. In 2010, the stillbirth rates ranged from 19.3 per 1000 births in the Kenyan site to 46.2 per 1000 births in the Pakistani site and by 2018, ranged from 9.7 per 1000 births in the Belagavi, India site to 40.8 per 1000 births in the Pakistani site. The 2010 neonatal mortality rates ranged from 19.0 per 1000 live births in the Kenyan site to 51.3 per 1000 live births in the Pakistani site with the 2018 neonatal mortality rates ranging from 9.2 per 1000 live births in the Zambian site to 50.2 per 1000 live births in the Pakistani site. In multivariate modeling, in some but not all sites, the reductions in stillbirth and neonatal death were significantly associated with an increase in the institutional deliveries. CONCLUSIONS: There was an increase in institutional delivery rates in all sites and a reduction in stillbirth and neonatal mortality rates in some of the GN sites over the past decade. The relationship between institutional delivery and a decrease in mortality was significant in some but not all sites. However, the stillbirth and neonatal mortality rates remain at high levels. Understanding the relationship between institutional delivery and stillbirth and neonatal deaths in resource-limited environments will enable development of targeted interventions for reducing the mortality burden. TRIAL REGISTRATION: The study is registered at clinicaltrials.gov . ClinicalTrial.gov Trial Registration: NCT01073475 .

Gender variations in neonatal and early infant mortality in India and Pakistan: a secondary analysis from the Global Network Maternal Newborn Health Registry.

BACKGROUND: To determine the gender differences in neonatal mortality, stillbirths, and perinatal mortality in south Asia using the Global Network data from the Maternal Newborn Health Registry. METHODS: This study is a secondary analysis of prospectively collected data from the three south Asian sites of the Global Network. The maternal and neonatal demographic, clinical characteristics, rates of stillbirths, early neonatal mortality (1-7 days), late neonatal mortality (8-28 days), mortality between 29-42 days and the number of infants hospitalized after birth were compared between the male and female infants. RESULTS: Between 2010 and 2018, 297,509 births [154,790 males (52.03%) and 142,719 females (47.97%)] from two Indian sites and one Pakistani site were included in the analysis [288,859 live births (97.1%) and 8,648 stillbirths (2.9%)]. The neonatal mortality rate was significantly higher in male infants (33.2/1,000 live births) compared to their female counterparts (27.4/1,000, p < 0.001). The rates of stillbirths (31.0 vs. 26.9/1000 births) and early neonatal mortality (27.1 vs 21.6/1000 live births) were also higher in males. However, there were no significant differences in late neonatal mortality (6.3 vs. 5.9/1000 live births) and mortality between 29-42 days (2.1 vs. 1.9/1000 live births) between the two groups. More male infants were hospitalized within 42 days after birth (1.8/1000 vs. 1.3/1000 live births, p < 0.001) than females. CONCLUSION: The risks of stillbirths, and early neonatal mortality were higher among male infants than their female counterparts. However, there was no gender difference in mortality after 7 days of age. Our results highlight the importance of stratifying neonatal mortality into early and late neonatal period to better understand the impact of gender on neonatal mortality. The information from this study will help in developing strategies and identifying measures that can reduce differences in sex-specific mortality.

Characterization of stimulus response curves obtained with transcranial magnetic stimulation from bilateral tibialis anterior muscles post stroke.

BACKGROUND: Stimulus response curves (SR curves), measured using transcranial magnetic stimulation (TMS) induced motor evoked potentials (MEP), yield important information regarding corticomotor connectivity. Limited understanding of SR curve analyses techniques for leg muscles after stroke may limit the utility of TMS data for walking recovery. OBJECTIVE: To compare linear and non-linear curve fitting for MEP responses from the non-paretic and paretic tibialis anterior (TA) muscles. METHODS: Accuracy of fit was measured using coefficient of determination (R2). Similarities of the fit were compared using slopes and area under the curve (AUC). RESULTS: The non-linear function demonstrated higher R2 and slopes. The AUC was not significantly different between the two analyses approaches. The non-linear non-paretic SR slopes and paretic AUC had significant associations with walking speed. CONCLUSION: Our results highlight the differences between non-linear and linear approaches to best fit the SR curves from bilateral TA muscles in stroke survivors. Although the linear function can appropriately fit the SR curve of the paretic and non-paretic TA, the non-linear function estimated a higher slope. We found the AUC to be a more robust measure that was not affected by the type of curve-fitting approach and only the AUC of the paretic TA showed significant association with walking speeds. A better understanding of SR curve fitting approaches for the TA muscles in individuals with chronic stroke allows for their optimal use in interpretation of TMS data and literature.

Influence of neurovascular mechanisms on response to tDCS: an exploratory study.

The beneficial effects of transcranial direct current stimulation (tDCS) for stroke rehabilitation are limited by the variability in changes in corticomotor excitability (CME) after tDCS. Neuronal activity is closely related to cerebral blood flow; however, the cerebral hemodynamics of neuromodulation in relation to neural effects have been less explored. In this study, we examined the effects of tDCS on cerebral blood velocity (CBv) in chronic stroke survivors using transcranial Doppler (TCD) ultrasound in relation to changes in CME and described the neurovascular characteristics of tDCS responders. Middle cerebral artery (MCA) CBv, cerebrovascular resistance (CVRi) and other cerebral hemodynamics-related variables were continuously measured before and after 15 min of 1 mA anodal tDCS to the lesioned lower limb M1. tDCS did not modulate CBv in the whole group and upon TMS-based stratification of responders and non-responders. However, at baseline, responders demonstrated lower CME levels, lower CBv and higher CVRi as compared to non-responders. These results indicate a possible difference in baseline CME and CBv in tDCS responders that may influence their response to neuromodulation. Future trials with a large sample size and repeated baseline measurements may help validate these findings and establish a relationship between neuromodulation and neurovascular mechanisms in stroke.

Effects of high intensity speed-based treadmill training on ambulatory function in people with chronic stroke: A preliminary study with long-term follow-up.

High intensity treadmill training has shown to be beneficial for stroke survivors, yet the feasibility and long-term effects remain unclear. In this study, we aimed to determine whether a 4-week high intensity speed-based treadmill training (HISTT) is feasible for chronic stroke survivors, and we examined its effects on ambulatory function, and long-term retention. Sixteen individuals post-stroke participated in 40 minutes of HISTT for four weeks at a frequency of three sessions per week. Gait speed was measured using the 10-meter walk test, endurance was measured using the 6-minute walk test, and quality of life was assessed using the Stroke Impact Scale (SIS) at baseline, post-training, and at 3-month follow-up. All participants successfully completed the training without any serious adverse events. Participants significantly increased fastest walking speed by 19%, self-selected walking speed by 18%, and walking endurance by 12% after the training. These improvements were maintained for 3 months after the intervention. Our results indicate that this modified speed-based high intensity walking program has the potential to be a feasible and effective method of gait training for stroke survivors. However, the small sample size and lack of a control group warrant caution in interpretation of results. Further studies are recommended to better understand effectiveness of this protocol in combination with other physical therapy interventions for functional recovery after stroke.

Non-invasive brain stimulation in the modulation of cerebral blood flow after stroke: A systematic review of Transcranial Doppler studies.

OBJECTIVE: Non-invasive brain stimulation (NIBS), such as repetitive TMS (rTMS) and transcranial direct current stimulation (tDCS), are promising neuromodulatory priming techniques to promote task-specific functional recovery after stroke. Despite promising results, clinical application of NIBS has been limited by high inter-individual variability. We propose that there is a possible influence of neuromodulation on cerebral blood flow (CBF), as neurons are spatially and temporally related to blood vessels. Transcranial Doppler (TCD), a clinically available non-invasive diagnostic tool, allows for evaluation of CBF velocity (CBFv). However, little is known about the role of neuromodulation on CBFv. METHODS: A systematic review of literature to understand the effects of NIBS on CBFv using TCD in stroke was conducted. RESULTS: Twelve studies fit our inclusion criteria and are included in this review. Our review suggested that CBFv and/or vasomotor reactivity maybe influenced by rTMS dosage (intensity and frequency) and the type of tDCS electrode montage. CONCLUSION: There is limited evidence regarding the effects of NIBS on cerebral hemodynamics using TCD and the usefulness of TCD to capture changes in CBFv after NIBS is not evident from this review. We highlight the variability in the experimental protocols, differences in the applied neurostimulation protocols and discuss open questions that remain regarding CBF and neuromodulation. SIGNIFICANCE: TCD, a clinically accessible tool, may potentially be useful to understand the interaction between cortical neuromodulation and CBFv.

Sirtuin1 is required for proper trophoblast differentiation and placental development in mice.

INTRODUCTION: Placental insufficiency, arising from abnormal trophoblast differentiation and function, is a major cause of fetal growth restriction. Sirtuin-1 (Sirt1) is a ubiquitously-expressed NAD-dependent protein deacetylase which plays a key role in numerous cellular processes, including cellular differentiation and metabolism. Though Sirt1 has been widely studied, its role in placentation and trophoblast differentiation is unclear. METHOD: Sirt1-heterozygous mice were mated and evaluated at various points during embryogenesis. In situ hybridization and immunohistochemistry were used to further characterize the placental phenotype of Sirt1-null mice. Wild-type (WT) and Sirt1-null mouse trophoblast stem cell (TSC) lines were derived from e3.5 littermate blastocysts. These cells were then evaluated at various points following differentiation. Differentiation was evaluated by expression of lineage specific markers using qPCR and flow cytometry, as well as Matrigel invasion assays. Global gene expression changes were evaluated using microarray-based RNA profiling; changes in specific pathways were validated using qPCR and western blot. RESULTS: In the absence of Sirt1, both embryos and placentas were small, with placentas showing abnormalities in both the labyrinthine layer and junctional zone. Sirt1-null TSCs exhibited an altered phenotype in both undifferentiated and differentiated states, phenotypes which corresponded to changes in pathways relevant to both TSC maintenance and differentiation. Specifically, Sirt1-null TSC showed blunted differentiation, and appeared to be suspended in an Epcamhigh trophoblast progenitor state. DISCUSSION: Our results suggest that Sirt1 is required for proper TSC differentiation and placental development.

Complex folding and misfolding effects of deer-specific amino acid substitutions in the ß2-α2 loop of murine prion protein.

The ß2-α2 loop of PrP(C) is a key modulator of disease-associated prion protein misfolding. Amino acids that differentiate mouse (Ser169, Asn173) and deer (Asn169, Thr173) PrP(C) appear to confer dramatically different structural properties in this region and it has been suggested that amino acid sequences associated with structural rigidity of the loop also confer susceptibility to prion disease. Using mouse recombinant PrP, we show that mutating residue 173 from Asn to Thr alters protein stability and misfolding only subtly, whilst changing Ser to Asn at codon 169 causes instability in the protein, promotes oligomer formation and dramatically potentiates fibril formation. The doubly mutated protein exhibits more complex folding and misfolding behaviour than either single mutant, suggestive of differential effects of the ß2-α2 loop sequence on both protein stability and on specific misfolding pathways. Molecular dynamics simulation of protein structure suggests a key role for the solvent accessibility of Tyr168 in promoting molecular interactions that may lead to prion protein misfolding. Thus, we conclude that 'rigidity' in the ß2-α2 loop region of the normal conformer of PrP has less effect on misfolding than other sequence-related effects in this region.

Type II natural killer T cells use features of both innate-like and conventional T cells to recognize sulfatide self antigens.

Glycolipids presented by the major histocompatibility complex (MHC) class I homolog CD1d are recognized by natural killer T cells (NKT cells) characterized by either a semi-invariant T cell antigen receptor (TCR) repertoire (type I NKT cells or iNKT cells) or a relatively variable TCR repertoire (type II NKT cells). Here we describe the structure of a type II NKT cell TCR in complex with CD1d-lysosulfatide. Both TCR α-chains and TCR ß-chains made contact with the CD1d molecule with a diagonal footprint, typical of MHC-TCR interactions, whereas the antigen was recognized exclusively with a single TCR chain, similar to the iNKT cell TCR. Type II NKT cell TCRs, therefore, recognize CD1d-sulfatide complexes by a distinct recognition mechanism characterized by the TCR-binding features of both iNKT cells and conventional peptide-reactive T cells.

DNMTs are required for delayed genome instability caused by radiation.

The ability of ionizing radiation to initiate genomic instability has been harnessed in the clinic where the localized delivery of controlled doses of radiation is used to induce cell death in tumor cells. Though very effective as a therapy, tumor relapse can occur in vivo and its appearance has been attributed to the radio-resistance of cells with stem cell-like features. The molecular mechanisms underlying these phenomena are unclear but there is evidence suggesting an inverse correlation between radiation-induced genomic instability and global hypomethylation. To further investigate the relationship between DNA hypomethylation, radiosensitivity and genomic stability in stem-like cells we have studied mouse embryonic stem cells containing differing levels of DNA methylation due to the presence or absence of DNA methyltransferases. Unexpectedly, we found that global levels of methylation do not determine radiosensitivity. In particular, radiation-induced delayed genomic instability was observed at the Hprt gene locus only in wild-type cells. Furthermore, absence of Dnmt1 resulted in a 10-fold increase in de novo Hprt mutation rate, which was unaltered by radiation. Our data indicate that functional DNMTs are required for radiation-induced genomic instability, and that individual DNMTs play distinct roles in genome stability. We propose that DNMTS may contribute to the acquirement of radio-resistance in stem-like cells.

Increased matrix synthesis by fibroblasts with decreased proliferation on synthetic chitosan-gelatin porous structures.

Influence of mechanical characteristics and matrix architecture of substrates used in cell culture is an important issue to tissue engineering. Chitosan-based materials have been processed into porous structures, injectable gels and membranes, and are investigated to regenerate various tissues. However, the effect of these structures on cell growth and matrix production in accordance with each of the differing scaffolds has not been examined. We investigated the influence of porous structures, hydrogels, and membranes on the growth of normal human fibroblasts and their matrix production in a serum-free system. We used chitosan alone and in combination with gelatin. Injectable hydrogels were prepared using 2-glycerol phosphate. From the same solution, porous scaffolds and membranes were formed using controlled rate freezing and lyophilization, and air-drying, respectively. Fibroblast growth was evaluated on the 4th and 10th days using flow cytometry and CFDA-SE pre-staining. Cell morphology was assessed using actin and nucleus staining. Total protein content, collagen, tropoelastin, and MMP2/MMP-9 activity in the media supernatant were assessed by BCA, Sircol™, Fastin Elastin, and fluorogeneic peptide assays. Collagen accumulated in the matrix was assessed by Sircol™ assay after pepsin/acetic acid digestion and by Masson's Trichrome staining. These results showed increased viability of fibroblasts on chitosan-gelatin porous scaffold with decreased proliferation relative to tissue culture plastic (TCP) surface despite the cells showing spindle shape. The total protein, collagen, and tropoelastin contents were higher in the spent media from chitosan-gelatin porous scaffolds compared to other conditions. MMP2/MMP9 activity was comparable to TCP. An increase in collagen content was also observed in the matrix, suggesting increased matrix deposition. In summary, matrix production is influenced by the form of chitosan structures, which significantly affects the regenerative process.

The stress relaxation characteristics of composite matrices etched to produce nanoscale surface features.

Many synthetic and xenogenic natural matrices have been explored in tissue regeneration, however, they lack either mechanical strength or cell colonization characteristics found in natural tissue. Moreover natural matrices such as small intestinal submucosa (SIS) lack sample to sample homogeneity, leading to unpredictable clinical outcomes. This work explored a novel fabrication technique by blending together the useful characteristics of synthetic and natural polymers to form a composite structure by using a NaOH etching process that produces nanoscale surface features. The composite scaffold was formed by sandwiching a thin layer of PLGA between porous layers of gelatin-chitosan. The etching process increased the surface roughness of PLGA membrane, allowing easy spreading of the hydrophilic gelatin-chitosan solution on its hydrophobic surface and reducing the scaffold thickness by nearly 50% than otherwise. The viscoelastic properties of the scaffold, an area of mechanical analysis which remains largely unexplored in tissue regeneration was assessed. Stress relaxation experiments of the "ramp and hold" type performed at variable ranges of temperature (25 degrees C and 37 degrees C), loading rates (3.125% s(-1) and 12.5% s(-1)) and relaxation times (60 s, 100 s and 200 s) found stress relaxation to be sensitive to temperature and the loading rate but less dependent on the relaxation time. Stress relaxation behavior of the composite matrix was compared with SIS structures at 25 degrees C (hydrated), 3.125% s(-1) loading rate and 100 s relaxation time which showed that the synthetic matrix was found to be strain softening as compared to the strain hardening behavior exhibited by SIS. Popularly used quasi-linear viscoelastic (QLV) model to describe biomechanics of soft tissues was utilized. The QLV model predicted the loading behavior with an average error of 3%. The parameters of the QLV model predicted using nonlinear regression analysis appear to be in concurrence with soft tissues.