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S Goyal

Publications and source records attributed to S Goyal.

At least 55 records · Page 3Linked to original sources
PubMed1998

Obstructive nephropathy in the neonatal rat is attenuated by epidermal growth factor.

BACKGROUND: Obstructive nephropathy is a primary cause of renal failure in infancy. Chronic unilateral ureteral obstruction (UUO) in the neonatal rat results in reduced renal expression of epidermal growth factor (EGF), renal tubular epithelial (RTE) cell apoptosis and interstitial fibrosis. We wished to determine whether these changes could be prevented by exogenous administration of EGF. METHODS: Thirty-three Sprague-Dawley rats underwent UUO within the first 48 hours of life, and received daily injections of either EGF (0.1 mg/kg/day) or saline (control) for the following seven days, after which obstructed and intact opposite kidneys were removed for study. These were compared to 11 sham-operated rats that received either no injections, EGF injections, or saline injections. Renal cell proliferation was determined by proliferating cell nuclear antigen, apoptosis was measured by the TUNEL technique, and the distribution of vimentin, clusterin, transforming growth factor-beta 1 (TGF-beta 1), and alpha-smooth muscle actin were determined by immunohistochemistry. Tubular dilation, tubular atrophy, and interstitial collagen deposition were quantitated by histomorphometry. RESULTS: Compared to controls, EGF treatment increased RTE cell proliferation in the obstructed kidney by 76%, decreased apoptosis by 80%, and reduced vimentin, clusterin and TGF-beta 1 immunostaining (all P < 0.05). EGF treatment reduced tubular dilation by 50%, atrophic tubules by 30%, and interstitial fibrosis by 50% (all P < 0.05). There was no significant effect of EGF on renal alpha smooth muscle actin distribution. There was no effect of saline or EGF injections on kidneys from sham-operated rats for any of the parameters studied. CONCLUSIONS: We conclude that EGF stimulates RTE cell proliferation and maturation and reduces apoptosis in the neonatal rat kidney subjected to chronic UUO. These effects may contribute to the reduction in tubular dilation, tubular atrophy, and interstitial fibrosis. By preserving renal development, administration of EGF attenuates the renal injury resulting from chronic UUO.

Animals↗
PubMed1998

Stabilization of dichloromethane-induced protein denaturation during microencapsulation.

This paper describes the denaturation of protein drugs by dichloromethane (DCM) during the primary emulsification step of the microencapsulation process using biodegradable polymer matrix for controlled-release application. It was found that interaction of proteins such as tetanus toxoid (TT), diphtheria toxoid (DT), ovine growth hormone (oGH), and human chorionic gonadotropin-based antifertility vaccine (beta-hCG-TT) with DCM during primary emulsification stages of particle formulation led to the precipitation of the proteins at the aqueous organic interface with concomitant reduction in their immunoreactivity. On the other hand, the B subunit of E. coli enterotoxin (LTB) was found to be comparatively stable toward the denaturing action of DCM. Attempts were made to overcome the DCM-induced denaturation by incorporation of stabilizers during the primary emulsification step of the particle formulation. Of the many additives tested to overcome the DCM-induced denaturation of proteins, serum albumins and polyvinyl alcohol (PVA) showed promising results in terms of retention of the immunoreactivity of the protein. TT stabilized by the incorporation of serum albumin during the primary emulsification step not only showed immunoreactivity in vitro, but also invoked antibody titers in rats comparable to those obtained for the native protein molecules. Incorporation of 2.5% of serum albumins in the internal aqueous phase not only protected the protein from the degradative action of DCM but also led to stabilized primary emulsion, which is necessary for uniform entrapment of protein drugs in the polymer matrix.

Animals↗
PubMed1997

Modulation of type VII collagen (anchoring fibril) expression by retinoids in human skin cells.

We examined the effects of retinoids on the expression of type VII collagen, a major component of anchoring fibrils, in human keratinocytes and amnion cells (WISH). All-trans retinoic acid (RA) (5 X l0(-6) M) decreased the steady-state levels of type VII collagen mRNA by at least 80% after 18 h. The inhibition was evident within 6 h after the addition of RA, maximal at 18 h, and was dose-dependent. Reduction of type VII mRNA expression also occurred when cell cultures were incubated with retinol, retinal, and 13-cis RA. Retinoid-mediated inhibition of type VII collagen mRNA expression was observed in keratinocytes growing in either serum-free keratinocyte growth medium (KGM) or KGM supplemented with 1.4 mM Ca2+. Cycloheximide blocked RA-mediated inhibition of type VII collagen mRNA, demonstrating the need for de novo protein synthesis. The mRNA levels for fibronectin and glyceraldehyde phosphate dehydrogenase were not affected by the retinoids, suggesting selective inhibition on type VII collagen expression. In addition, the decrease in type VII collagen mRNA was accompanied by a parallel decrease in secretion of the 290 kDa, type VII collagen alpha chains.

Amnion↗
PubMed1997

Fracture of ossified Achilles tendon.

Ruptures of Achilles tendon are quite common. We here report a case of fracture in an ossified mass of Achilles tendon in an 84-year-old male patient. The mass occurred 78 years following surgery for bilateral equinus deformities of his ankle. Clinically, he had a palpably definite gap in the ossified area of the Achilles tendon, which was confirmed by a roentgenogram and a magnetic resonance scan of his left ankle. He was treated conservatively in a plaster cast for 12 weeks. The overall functional result a year after his treatment was quite satisfactory.

Achilles Tendon↗
PubMed1997

Death of a wild wolf from canine parvoviral enteritis.

A 9-mo-old female wolf (Canis lupus) in the Superior National Forest of Minnesota (USA) died from a canine parvovirus (CPV) infection. This is the first direct evidence that this infection effects free-ranging wild wolves.

Animals↗
PubMed1996

Two-hybrid system as a model to study the interaction of beta-amyloid peptide monomers.

The kinetics of amyloid fibril formation by beta-amyloid peptide (Abeta) are typical of a nucleation-dependent polymerization mechanism. This type of mechanism suggests that the study of the interaction of Abeta with itself can provide some valuable insights into Alzheimer disease amyloidosis. Interaction of Abeta with itself was explored with the yeast two-hybrid system. Fusion proteins were created by linking the Abeta fragment to a LexA DNA-binding domain (bait) and also to a B42 transactivation domain (prey). Protein-protein interactions were measured by expression of these fusion proteins in Saccharomyces cerevisiae harboring lacZ (beta-galactosidase) and LEU2 (leucine utilization) genes under the control of LexA-dependent operators. This approach suggests that the Abeta molecule is capable of interacting with itself in vivo in the yeast cell nucleus. LexA protein fused to the Drosophila protein bicoid (LexA-bicoid) failed to interact with the B42 fragment fused to Abeta, indicating that the observed Abeta-Abeta interaction was specific. Specificity was further shown by the finding that no significant interaction was observed in yeast expressing LexA-Abeta bait when the B42 transactivation domain was fused to an Abeta fragment with Phe-Phe at residues 19 and 20 replaced by Thr-Thr (AbetaTT), a finding that is consistent with in vitro observations made by others. Moreover, when a peptide fragment bearing this substitution was mixed with native Abeta-(1-40), it inhibited formation of fibrils in vitro as examined by electron microscopy. The findings presented in this paper suggest that the two-hybrid system can be used to study the interaction of Abeta monomers and to define the peptide sequences that may be important in nucleation-dependent aggregation.

Alzheimer Disease↗
PubMed1996

Prolonged survival follows resection of oesophageal SCC downstaged by prior chemoradiotherapy.

BACKGROUND: The poor survival rate of surgically treated patients with oesophageal cancer has not improved substantially over the last 25 years, but combined modality therapy has shown early promising results. METHODS: A prospective study was undertaken to determine the effect of pre-operative synchronous chemoradiotherapy followed by oesophagectomy in 53 patients with squamous cell carcinoma (SCC) of the oesophagus. The patient group was unselected, other than by fitness for surgery. RESULTS: In 25% of patients, complete pathological regression of the tumour was achieved. All but one of the patients in this subgroup had T2 tumours on pre-operative clinical staging and two had evidence of lymph node involvement, but postoperative pathological examination revealed that pre-operative chemoradiotherapy had downstaged their disease to T0N0. There was no hospital mortality in this subgroup and the actuarial 7 year survival was 69%. CONCLUSIONS: For squamous oesophageal tumours deep to the submucosa this is an extremely good survival. For the present, this form of therapy for SCC of the oesophagus appears capable of achieving results comparable to, or better than, those reported for 3-field lymphadenectomy.

Adult↗
PubMed1995

Lasers.

Explore the source record for details and available documents.

Humans↗
PubMed1994

Effect of cysteine substitutions on the mitogenic activity and stability of recombinant human keratinocyte growth factor.

Human Keratinocyte growth factor (hKGF), a member of the FGF family of growth factors, contains five cysteines at amino acid positions 1, 15, 40, 102, and 106. We expressed five cysteine mutants of hKGF in which the cysteines were cumulatively replaced with alanine or serine, starting with cysteine-1. Recombinant hKGF has an inherently higher mitogenic activity and stability to heat and acid than reported for glycosylated hKGF. Mitogenic activity is increased an additional 2.6 fold by substitution of cysteine-1 with alanine. Mutants with the conserved cysteine substituted at position 40 were more susceptible to heat inactivation than rhKGF, but showed no significant difference in acid inactivation. Cysteine-free rhKGF is mitogenic, demonstrating that neither cysteines nor disulfide bonds are required for mitogenic activity. However, cysteine-free rhKGF does not bind Heparin-Sepharose and is unstable to heat and acid compared to rhKGF, suggesting that the cysteines have a role in maintaining KGF's structure. This information will useful in the development of a more stable and more potent wound healing agent from hKGF.

Animals↗
PubMed1994

Structural and functional role of lipids in yeast and mycelial forms of Candida albicans.

The levels of total lipids, sterols and phospholipids were found to be significantly higher in the mycelial form (log phase) of Candida albicans than in the yeast form. Increased phospholipid levels in the mycelial form were due to higher levels of phosphatidylcholine, phosphatidylserine and phosphatidylinositol. Analyses of fatty acid composition also revealed higher levels of myristic acid (40%) in the yeast form, resulting in higher levels of saturated lipids than in the mycelial form. The changes in the lipid composition were also manifested in altered thermotropic phase behavior as gel-to-liquid crystalline phase transitions were observed at 36 and 27 degrees C for the lipids of the yeast and mycelial forms, respectively. These changes coincided with higher uptake rate, i.e., Km and Vmax values, for the transport of L-proline and with a higher sensitivity of the mycelial form against antifungal drugs.

Antifungal Agents↗
PubMed1992

Phospholipid composition and subcellular distribution in yeast and mycelial forms of Candida albicans.

Lipids were found to constitute 3.9% and 4.7% of the dry weight of yeast and mycelial forms of Candida albicans, respectively. Phospholipids were localized mainly in the microsomal fraction of both growth forms and phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine and cardiolipin were the major phospholipids. Myristic acid and palmitic acid were the predominant fatty acids in the yeast form while the mycelial form contained palmitic, palmitoleic and oleic acid as major fatty acids. Yeast forms showed significantly higher specific activities of intracellular phospholipase A and lysophospholipase when compared with mycelial forms. No significant difference in the specific activity of extracellular phospholipase A was seen in either morphogenic form while the activity of extracellular lysophospholipase was higher in the yeast form. These results are discussed in the context of the virulence of this fungus.

Candida albicans↗
PubMed1991

Agalactosyl IgG: an aid to differential diagnosis in early synovitis.

Sixty consecutive patients presenting with early-onset synovitis were studied by measuring rheumatoid factor (RF) titers and the percentage of oligosaccharide chains attached to the C gamma 2 domain of IgG that lack galactose (GAL[0]). After 2 years of followup, 39 patients (65%) had developed rheumatoid arthritis (RA), and 21 had developed a variety of other inflammatory joint diseases. A combination of RF positivity and GAL(0) levels above the age-corrected mean gave a positive predictive value for a diagnosis of RA in 94% of these patients. These observations may well have clinical utility.

Adult↗