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Biomedical subjects

R Verma

Publications and source records attributed to R Verma.

At least 37 records · Page 2Linked to original sources
PubMed2000

Colonic inflammation found at diagnosis of juvenile retention polyps in pediatric patients.

OBJECTIVE: The finding of colonic inflammation concurrently with a juvenile retention polyp (JRP) may have prognostic value. However, the significance of abnormal mucosal histology with JRP has not been evaluated. We evaluated the significance of mucosal histology at the time of JRP removal with respect to future development of inflammatory bowel disease (IBD) and polyp recurrence. METHODS: The medical records of patients who had an endoscopic polypectomy performed at the Children's Hospital of Philadelphia (CHOP) from 1/1/87 through 4/30/98 were retrospectively reviewed. RESULTS: JRP was histologically identified in 96 patients. A total of 54 patients had colonic mucosal biopsies: 30 (55.6%) had normal histology and 24 (44.4%) had colitis. Of the 24 patients with colitis, 14 patients (58.3%) had inflammation at the polyp site. Twelve of these patients had additional inflammation elsewhere in the colon. Nine (37.5%) had inflammation elsewhere in the colon; however, biopsies around the polyp site were not obtained. One patient with inflammation did not have the location of the polyp documented. Four patients (16.7%) had IBD at the time of polypectomy; two were diagnosed prior and two coincident with JRP. None have subsequently been diagnosed with IBD. There was no difference in polyp recurrence between those with or without inflammation (16.7% [4/24] vs 10.0% [3/30]). The mean follow-up period was 72.4 months (range, 5-142 months). CONCLUSIONS: In our experience, histological mucosal inflammation is a common finding with JRP. This inflammation may be a precursor for the development of JRP but has no predictive value for polyp recurrence. This colitis does not seem to be associated with IBD.

Adolescent↗
PubMed2000

Cks1 is required for G(1) cyclin-cyclin-dependent kinase activity in budding yeast.

p13(suc1) (Cks) proteins have been implicated in the regulation of cyclin-dependent kinase (CDK) activity. However, the mechanism by which Cks influences the function of cyclin-CDK complexes has remained elusive. We show here that Cks1 is required for the protein kinase activity of budding yeast G(1) cyclin-CDK complexes. Cln2 and Cdc28 subunits coexpressed in baculovirus-infected insect cells fail to exhibit protein kinase activity towards multiple substrates in the absence of Cks1. Cks1 can both stabilize Cln2-Cdc28 complexes and activate intact complexes in vitro, suggesting that it plays multiple roles in the biogenesis of active G(1) cyclin-CDK complexes. In contrast, Cdc28 forms stable, active complexes with the B-type cyclins Clb4 and Clb5 regardless of whether Cks1 is present. The levels of Cln2-Cdc28 and Cln3-Cdc28 protein kinase activity are severely reduced in cks1-38 cell extracts. Moreover, phosphorylation of G(1) cyclins, which depends on Cdc28 activity, is reduced in cks1-38 cells. The role of Cks1 in promoting G(1) cyclin-CDK protein kinase activity both in vitro and in vivo provides a simple molecular rationale for the essential role of CKS1 in progression through G(1) phase in budding yeast.

Adaptor Proteins, Signal Transducing↗
PubMed2000

Pathological laughter as heralding manifestation of left middle cerebral artery territory infarct: case report and review of literature.

Clinical, radiological and pathological studies in patients with stroke, presenting with pathological laughter as heralding manifestation, have shown lesions in the internal capsule and thalamus, basal ganglion, hypothalamus and ventral pons. In this report a patient with similar manifestation and having a cortical infarct in the territory supplied by superior division of middle cerebral artery is being presented. Our case suggests possible influence of dominant cerebral hemisphere, especially of Broca's area, on the motor control of laughter.

Dominance, Cerebral↗
PubMed2000

Anhidrotic Ectodermal Dysplasia (Christ-Seimens-Touraine syndrome)--case report with a review.

Anhidrotic ectodermal dysplasia commonly transmitted as an x-linked recessive disorder is very rare. The complete syndrome occurs in males and females are carriers. Our patients comprised two sisters who had the complete syndrome. This is much rarer and is reported to be inherited as autosomal recessive disorder, there are only a few case reports of females presenting with a complete syndrome in the literature.

Adolescent↗
PubMed1999

A quantitative analysis of G-actin binding proteins and the G-actin pool in developing chick brain.

The large G-actin pool in individual actively motile cells has been shown to be maintained primarily by the actin sequestering protein thymosin beta four (Tbeta4). It is not clear whether Tbeta4 or an isoform also plays a primary role in neural tissue containing highly motile axonal growth cones. To address this question we have made a definitive analysis of the relative contributions of all the known G-actin sequestering proteins: Tbeta4, Tbeta10, profilin, and phosphorylated (inactive) and unphosphorylated (potentially active) forms of both ADF and cofilin, in relation to the G-actin pool in developing chick brain at embryonic days 13 and 17. From our measurements we estimate the intracellular concentration of G-actin as 30-37 microM and of Tbeta4 as 50-60 microM in an 'average' brain cell in embryonic chick brain. No other beta thymosin isoforms were detected in these brain extracts. The ratio of soluble, unphosphorylated ADF to Tbeta4 is only 1:7 at 13 embryonic days, but increases to 1:4 at 17 days. Profilin and cofilin concentrations are an order of magnitude lower than Tbeta4. Combining the contributions of Tbeta4, unphosphorylated ADF and unphosphorylated cofilin, we estimate a mean G-actin critical concentration of approximately 0.45 microM and approximately 0.2 microM, respectively, in day 13 and day 17 embryonic brain extracts, suggesting a significant developmental decrease. We conclude that (a) Tbeta4 is the major actin sequestering protein in embryonic chick brain and the only beta thymosin isoform present; (b) ADF may play a significant developmental role, as its concentration changes significantly with age; (c) the known G-actin binding proteins can adequately account for the G-actin pool in embryonic chick brain.

Actin Depolymerizing Factors↗
PubMed1999

Rapid detection of Mycobacterium bovis on its lipid profile by thin layer chromatography.

Sixteen Mycobacterium bovis (M. bovis) strains isolated from bovine tissues and one standard reference strain of M. bovis AN5 alongwith other species of mycobacteria for comparison were investigated for the presence of phenolic glycolipid (PGL) and phthiocerol dimycocerosate (PDIM) for rapid identification of M. bovis by thin-layer chromatography (TLC). The study indicated presence of PGL with an Rf value of 0.75 in chloroform-methanol solvent in all 17 M. bovis strains. The dimycocerostate A corresponding to spot A was the major constituent among all the three spots in M. bovis strains. TLC appeared to be a promising alternative to conventional biochemical methods for identification of M. bovis taking into consideration both PGL and PDIM lipids.

Animals↗
PubMed1999

Nephrin localizes to the slit pore of the glomerular epithelial cell.

BACKGROUND: Recognition that mutation of the protein nephrin, encoded by the NPHS1 gene, singly results in the cellular alterations that result in foot process effacement, and nephrotic range proteinuria emphasizes the pivotal role that this protein plays in regulating glomerular filter integrity. This article reports the development of reagents necessary to study the biology of nephrin in mouse, and describes the initial characterization of the nephrin protein. METHODS: A cDNA including the full-length mouse nephrin open reading frame was cloned and sequenced. Immuno-affinity purified polyclonal antiserum directed against the cytoplasmic domain of mouse nephrin was developed. RESULTS: Nephrin identified in mouse glomerular extract was found to be a glycoprotein with an apparent molecular mass of 185 kDa. As detected by indirect immunofluorescence microscopy and immunogold electron microscopy, nephrin was located only in visceral glomerular epithelial cells, where it was targeted to intercellular junctions of mature podocyte foot processes. In developing glomeruli of newborn mouse, antinephrin immunolocalized to the earliest slit pore regions between differentiating podocytes, sites where slit diaphragms first become visible. CONCLUSION: As a putative cell adhesion molecule of the immunoglobulin superfamily, nephrin likely participates in cell-cell interactions between podocyte foot processes and may represent a component of the slit diaphragm.

Age Factors↗
PubMed1998

Antibody engineering: comparison of bacterial, yeast, insect and mammalian expression systems.

Engineered antibody molecules, and their fragments, are being increasingly exploited as scientific and clinical tools. However, one factor that can limit the applicability of this technology is the ability to express large amounts of active protein. In this review we describe the relative advantages and disadvantages of bacterial, yeast, insect and mammalian expression systems, and discuss some of the problems that can be encountered when using them. There is no 'universal' expression system, that can guarantee high yields of recombinant product, as every antibody-based molecule will pose its own problems in terms of expression. As a result the choice of system will depend on many factors, including the molecular species being expressed, the precise sequence of the individual antibody and the preferences of the individual investigator. However, there are general rules with regards to the design of expression vectors and systems which will help the investigator to make informed choices as to which strategy might be appropriate for their application.

Animals↗
PubMed1998

The intermittent ductus revisited: echocardiographic evidence and successful coil occlusion: a case report and review of literature.

Intermittent occurrence of a large ductal shunt by physical examination and Doppler echocardiography is reported. Cineangiography confirmed a tubular ductus arteriosus with an angulated, narrow, pulmonary end. Presumably this angulation intermittently caused functional closure of the ductus. Trans-arterial delivery of coils resulted in complete occlusion.

Blood Flow Velocity↗
PubMed1998

Haemorrhagic septicaemia vaccines.

Haemorrhagic septicaemia (HS), an economically important disease of cattle and buffaloes, is caused by Pasteurella multocida (6:B). Vaccination against this disease is widely practised. Plain broth bacterins, or alum precipitated and aluminium hydroxide gel vaccines are administered twice a year since these vaccines offer an immunity of 4-6 months. Many countries use oil adjuvant vaccine (OAV), which gives both a higher degree and a longer duration of immunity up to 1 year. A double emulsion and multiple emulsion vaccine consisting of a thin viscosity have also been experimentally developed that gave an immunity parallel to OAV. Recently, a live vaccine developed from a fallow deer strain (B:3,4) has been used in Myanmar that offers an immunity for more than a year but is not free from constraints. The present review provides information on HS vaccines developed from time to time using whole bacteria or their components. The kinetics and isotype of antibody and cell-mediated immune responses have also been poorly understood so far, and hence information on their role in protection against HS is reviewed.

Animals↗
PubMed1997

Phosphorylation of Sic1p by G1 Cdk required for its degradation and entry into S phase.

G1 cyclin-dependent kinase (Cdk)-triggered degradation of the S-phase Cdk inhibitor Sic1p has been implicated in the transition from G1 to S phase in the cell cycle of budding yeast. A multidimensional electrospray mass spectrometry technique was used to map G1 Cdk phosphorylation sites in Sic1p both in vitro and in vivo. A Sic1p mutant lacking three Cdk phosphorylation sites did not serve as a substrate for Cdc34p-dependent ubiquitination in vitro, was stable in vivo, and blocked DNA replication. Moreover, purified phosphoSic1p was ubiquitinated in cyclin-depleted G1 extract, indicating that a primary function of G1 cyclins is to tag Sic1p for destruction. These data suggest a molecular model of how phosphorylation and proteolysis cooperate to bring about the G1/S transition in budding yeast.

Amino Acid Sequence↗
PubMed1997

Protection, humoral and cell-mediated immune responses in calves immunized with multiple emulsion haemorrhagic septicaemia vaccine.

A multiple emulsion (ME), vaccine against Pasteurella multocida (P52) infection in cattle was prepared and the efficiency in terms of immunity to direct challenge, duration of this immunity for up to 1 year and the role of humoral and cell-mediated immune mechanisms were studied. ME vaccine was sterile, safe and was potent when tested in rabbits and calves. Nineteen calves were immunized with a single 4 ml dose of ME vaccine intramuscularly. Group of these calves were challenge infected with virulent P. multocida (P52) (10(-1) 18 h old broth culture) given by the subcutaneous route at 21 days, 3 months, 6 months, 9 months and 1 year. All the immunized calves withstood challenge infection and showed 100% protection. Humoral immune response was measured by indirect haemagglutination test (IHA) and enzyme-linked immunosorbant assay (ELISA). Statistically ELISA values were found to be superior to IHA values because of small coefficient of variance. A fall in mean antibody titres during 24 h, 48 h, post-challenge infection was recorded whereas a steady increase in the titre after 72 h up to 10 days was noticed. The prechallenge mean titre in animals correlated with survival of animals. Humoral antibodies were detected as early as 7 day post-immunization and persisted to 1 year after immunization. Leucocyte migration inhibition test showed > 20% migration inhibition during all pre- and post-challenge periods in animals suggesting an involvement of cell-mediated immune mechanism in protection. Our findings suggested that both humoral and cell-mediated immune responses contribute to protection in vaccinated animals. The results of these studies of ME vaccine showed that it can be successfully used for the effective control of haemorrhagic septicaemia.

Animals↗
PubMed1997

Renal osmotic stress-induced cotransporter: expression in the newborn, adult and post-ischemic rat kidney.

The renal osmotic stress-induced cotransporter (ROSIT), a new putative member of a family of organic solute transporters, is highly expressed in the kidney. Our in situ hybridization data now reveal that large amounts of ROSIT mRNA can be found in the S3 segment of the proximal tubule. In the developing kidney, ROSIT mRNA is expressed after the S-shaped body stage. Because the S3 segment is the major site of damage in the post-ischemic kidney, we evaluated alterations in ROSIT mRNA expression after ischemic acute tubular necrosis. Renal osmotic stress-induced cotransporter mRNA levels were already decreased eight hours post-ischemia. At seven days post-ischemia, ROSIT mRNA reappeared in a mosaic pattern in the regenerating S3 segment, being fully expressed three weeks after the insult except for focal areas. The exact localization of this putative osmolyte transporter in the kidney, together with that of other known osmolyte transporter will contribute to a better understanding of the mechanism of medullary osmolyte accumulation and its vectorial transport.

Age Factors↗
PubMed1997

SIC1 is ubiquitinated in vitro by a pathway that requires CDC4, CDC34, and cyclin/CDK activities.

Traversal from G1 to S-phase in cycling cells of budding yeast is dependent on the destruction of the S-phase cyclin/CDK inhibitor SIC1. Genetic data suggest that SIC1 proteolysis is mediated by the ubiquitin pathway and requires the action of CDC34, CDC4, CDC53, SKP1, and CLN/CDC28. As a first step in defining the functions of the corresponding gene products, we have reconstituted SIC1 multiubiquitination in DEAE-fractionated yeast extract. Multiubiquitination depends on cyclin/CDC28 protein kinase and the CDC34 ubiquitin-conjugating enzyme. Ubiquitin chain formation is abrogated in cdc4ts mutant extracts and assembly restored by the addition of exogenous CDC4, suggesting a direct role for this protein in SIC1 multiubiquitination. Deletion analysis of SIC1 indicates that the N-terminal 160 residues are both necessary and sufficient to serve as substrate for CDC34-dependent ubiquitination. The complementary C-terminal segment of SIC1 binds to the S-phase cyclin CLB5, indicating a modular structure for SIC1.

Anaphase-Promoting Complex-Cyclosome↗