Mesenchymal stem cell tailored bioengineered scaffolds derived from bubaline diaphragm and aortic matrices for reconstruction of abdominal wall defects

Bioengineered scaffolds derived from the decellularized extracellular matrix (ECM) obtained from discarded animal organs and tissues are attractive candidates for regenerative medicine applications. Tailoring these scaffolds with stem cells enhances their regeneration potential making them a suitable platform for regenerating damaged tissues. Thus, the study was designed to investigate the potential of mesenchymal stem cells tailored acellular bubaline diaphragm and aortic ECM for the repair of full-thickness abdominal wall defects in a rabbit model. Tissues obtained from bubaline diaphragm and aorta were decellularized and bioengineered by seeding with rabbit bone marrow derived mesenchymal stem cells (r-BMSC). Full-thickness abdominal wall defects of 3 cm × 4 cm size were created in a rabbit model and repaired using five different prostheses, namely, polypropylene sheet, nonseeded diaphragm ECM, nonseeded aorta ECM, r-BMSC bioengineered diaphragm ECM, and r-BMSC bioengineered aorta ECM. Results from the study revealed that biological scaffolds are superior in comparison to synthetic polymer mesh for regeneration in terms of collagen deposition, maturation, neovascularization, and lack of any significant (P > 0.05) adhesions with the abdominal viscera. Seeding with r-BMSC significantly increased (P < 0.05) the collagen deposition and biomechanical strength of the scaffolds. The bioengineered r-BMSC seeded acellular bubaline diaphragm showed even superior biomechanical strength as compared to synthetic polymer mesh. Tailoring of the scaffolds with the r-BMSC also resulted in significant reduction (P < 0.01) in antibody and cell mediated immune reactions to the xenogeneic scaffolds in rabbit model.

Selection of biological prosthesis for abdominal wall repair on the basis of in vitro biocompatibility determination

Research on prostheses for repairing abdominal wall defects has progressed through past decades for developing an ideal prosthesis. The study was designed to compare different extracellular matrix (ECM) derived biological prostheses as alternate to conventional synthetic polymeric prostheses for the repair of full thickness abdominal wall defects. Five biological scaffolds derived from bovine diaphragm, bovine aorta, bovine gall bladder, porcine gall bladder, and rabbit skin were prepared and screened for their in vitro biocompatibility. Decellularized ECMs were subjected to various biocompatibility analyses, namely, water absorption potential, matrix degradation analysis, biomechanical testing, and cytocompatibility analysis. Though the rabbit skin displayed maximum biomechanical strength, due to its rapid degradation, it failed to fulfill the criteria of an ideal prosthesis. ECMs derived from bovine diaphragm and aorta were found to be superior than others based upon hydration and matrix degradation analysis, with best scores for bovine diaphragm followed by bovine aorta. The bovine diaphragm and aorta also displayed sufficient biomechanical strength, with diaphragm being the second highest (next to rabbit skin), in biomechanical strength followed by aorta. None of the biological prosthesis revealed any cytotoxicity. Thus, bovine diaphragm and aorta derived ECM fulfill the necessary criteria for their use as biological prosthesis. Because these prostheses are biocompatible, apart from their low cost, ease of availability, and simple preparation, they present a potential alternative to synthetic prosthesis for repair of abdominal wall defects, especially in veterinary patients.

Pregnancy outcome and cord blood cotinine level: A cross-sectional comparative study between secondhand smokers and non-secondhand smokers

OBJECTIVE

To compare the pregnancy outcome and cord blood cotinine levels between secondhand smokers and non-secondhand smokers.

STUDY DESIGN

This was a cross-sectional comparative study in a Malaysian tertiary obstetric hospital involving 200 non-smoking pregnant women at term, of whom 100 were secondhand smokers and 100 were non-secondhand smokers. Those with multiple pregnancies, with a body mass index (BMI) of more than 30kg/m² or who delivered by Caesarean section were excluded. The participants' basic demographic details, delivery details, neonatal outcome and placental weight were recorded. Umbilical cord blood samples were obtained, and cord blood cotinine levels were measured with a Cotinine ELISA kit. The primary outcomes were baby's birth weight, length, and head circumference, Apgar score at 5min and placental weight. The secondary outcome was difference in cord blood cotinine levels between the two groups and the correlation of these differences with the neonatal outcome.

RESULTS

The secondhand smoker group had significantly lower baby weight (2.94±0.31kg vs 3.05±0.40kg), head circumference (30.87±2.35cm vs 37.13±2.36cm), length (46.58±1.95cm vs 51.53±2.05cm) and placental weight (520±73.5g vs 596±61.3g) and significantly higher cord blood cotinine levels (16.35±12.84ng/mL vs 0.56±0.22ng/mL). Cord blood cotinine levels had significant negative correlations with placental weight (r=-0.461), baby's weight (r=-0.297), baby's head circumference (r=-0.501) and baby's length (r=-0.374).

CONCLUSION

Secondhand smoke increases the incidence of adverse pregnancy outcomes (newborns'anthropometric measurements and placental weight) and causes higher cord blood cotinine levels.

Cloning and sequencing of hfq (host factor required for synthesis of bacteriophage Q beta RNA) gene of Salmonella Typhimurium isolated from poultry

AIM

The aim was to clone and sequence hfq gene of Salmonella Typhimurium strain PM-45 and compare its sequence with hfq gene of other serovar of Salmonella.

MATERIALS AND METHODS

Salmonella Typhimurium strain PM-45 was procured from the G. B. Pant University of Agriculture and Technology, Pantnagar, India. The genomic DNA was isolated from Salmonella Typhimurium. Hfq gene was polymerase chain reaction (PCR) amplified from the DNA using specific primers, which was subsequently cloned into pET32a vector and transformed into Escherichia coli BL21 pLys cells. The recombinant plasmid was isolated and subjected to restriction enzyme digestion as well as PCR. The clone was then sequenced. The sequence was analyzed and submitted in GenBank.

RESULTS

PCR produced an amplicon of 309 bp. Restriction digestion of the recombinant plasmid released the desired insert. The hfq sequence shows 100% homology with similar sequences from other Salmonella Typhimurium isolates. Both nucleotide and amino acid sequences are highly conserved. The submitted sequence is having Genbank accession no KM998764.

CONCLUSION

Hfq, the hexameric RNA binding protein is one of the most important post-transcriptional regulator of bacteria. The sequence of hfq gene of Salmonella Typhimurium is highly conserved within and between Salmonella enterica serovars. This gene sequence is probably under heavy selection pressure to maintain the conformational integrity of its product in spite of its being not a survival gene.

Vaginal Reconstruction With a Rectus Abdominis Musculoperitoneal Flap

In more than 300 clinical cases, the authors have observed and documented the presence of a branch of the deep inferior epigastric artery that penetrates the posterior rectus sheath near the umbilicus. Their cadaveric anatomic and animal injection studies confirm the vascularity of the peritoneum via the deep inferior epigastric artery. They report 2 patients treated with a new technique of vaginal reconstruction using a thin, pliable flap with a peritoneal-lined rectus abdominis muscle based on the deep inferior epigastric vessels.

Immunoregulatory treatment for minimal change nephrotic syndrome

Immunological studies were performed in 18 children with minimal change nephrotic syndrome proved by biopsy examination during relapse and in 15 age matched controls. All 18 children showed dysfunction of cell mediated immunity as evidenced by low absolute lymphocyte count, low blastogenesis index in response to phytohaemagglutinin stimulation, and reduced skin sensitivity to dinitrochlorobenzene when compared with controls. All 18 patients had low serum IgG concentrations, while the IgA, IgM, and C3 concentrations in the serum were within normal limits. Based on the evidence of depressed cell mediated immunity, 14 patients with nephrotic syndrome were treated with an immunoregulatory drug l-tetramisole (levamisole) for a period of 20-24 weeks. Six patients went into complete remission within 4-20 weeks of treatment, a further six patients went into partial remission, while two did not respond. On follow up (six to 24 months after stopping levamisole), of the six patients who achieved complete remission, four continued to maintain the state and two relapsed after roughly six months. Of the six patients who achieved partial remission, two went into complete remission, two continued to be in partial remission, and two relapsed.

Multilamellar cytosomes in a particular form of late-infantile amaurotic idiocy

There is a particular form of late-infantile amaurotic idiocy in which no clear chemical-pathological or unique enzyme abnormalities have been identified to date. A distinctive morphological feature has been recognized on electron microscopical examination of tissues from these patients, which has been descriptively labeled with various terms, including "multilamellar cytosomes" (MLC). Illustrations of MLC in a patient with this late-infantile form of cerebroretinal degeneration show their reactivity with the periodic acid-silver methenamine reaction for glycoproteins. The MLC are shown to be morphologically identical in cerebral tissue obtained at biopsy, in the same tissue obtained three years later at autopsy, and in skeletal muscle.