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Biomedical subjects

R Misra

Publications and source records attributed to R Misra.

At least 91 records · Page 5Linked to original sources
PubMed1995

Molecular analysis of asmA, a locus identified as the suppressor of OmpF assembly mutants of Escherichia coli K-12.

We present the molecular characterization of the asmA gene, whose product is involved in the assembly of outer membrane proteins in Escherichia coli K-12. The asmA locus was initially identified as a site for suppressor mutations of an assembly defective OmpF315. Our data suggest that these suppressor mutations either completely abolish or reduce asmA expression and can be complemented in trans by plasmid clones carrying asmA sequences. The recessive nature of asmA suppressor mutations suggests that the functional AsmA protein participates in inhibiting the assembly of OmpF315 and other mutant OmpFs. As the assembly of wild-type and parental OmpF proteins was not affected by asmA mutations, AsmA must provide an environment refractory only to the assembly of mutant OmpF proteins. However, we cannot completely rule out the possibility that AsmA plays a minor role in the assembly of wild-type and parental OmpF in wild-type cells. The presence of a putative signal sequence within the amino-terminal sequence of AsmA suggests that it is either a periplasmic or an outer membrane protein. This predicted location of AsmA is compatible with its role in the assembly of outer membrane proteins.

Alleles↗
PubMed1995

Lack of natural killer cell augmentation in vitro by human interferon gamma in a subset of patients with systemic sclerosis.

Systemic sclerosis (SSc) is a generalized connective tissue disorder characterized by fibrosis of skin and various viscera. Natural killer (NK) cells are a subset of lymphocytes that can lyse targets without prior sensitization. Few studies have tried to assess NK cell function in patients with SSc. To evaluate NK cell cytotoxicity in patients with SSc and to see the extent of its augmentation in vitro by human interferon (hIFN) gamma in the clinical subset of limited and diffuse cutaneous diseases, we evaluated 27 patients with SSc and 22 age- and sex-matched controls by 51Cr release assay. Fifteen patients had limited cutaneous disease (mean disease duration 6.2 +/- 2.7 years) and 12 diffuse cutaneous disease (mean disease duration 5.7 +/- 2.4 years). Patients with limited SSc had significantly higher baseline NK cell function than controls (p < 0.05) and the augmentation following in vitro stimulation with hIFN gamma was negligible. Patients with diffuse SSc had lower baseline NK cell cytotoxicity than controls but this was not statistically significant. Augmentation with hIFN gamma in this group was comparable to controls. This study suggests that NK cells may have a role in the pathophysiology of this disease.

Adult↗
PubMed1995

A syndrome of fibrosing pleuritis, pericarditis, and synovitis with infantile contractures of fingers and toes in 2 sisters: "familial fibrosing serositis".

We describe a family in which 2 sisters born to consanguineous parents developed childhood onset fibrosing pleuritis in association with constrictive pericarditis and bilateral deforming arthropathy of large and small joints of upper and lower extremities including flexion contractures of several fingers (camptodactyly) and toes. One patient also had mitral value prolapse. Histopathological examination of the synovium and pericardium revealed fibrosis, and ultrastructural study of synovium showed abundant inter and intracellular mesh of 9 nm microfibrils. We describe this distinct clinicopathological entity with pleiotropic manifestations, the common features of which appears to be the fibrosis of serous membranes. Therefore, the term "familial fibrosing serositis" is proposed for this entity.

Adolescent↗
PubMed1994

1,N6-etheno deoxy and ribo adenosine and 3,N4-etheno deoxy and ribo cytidine phosphoramidites. Strongly fluorescent structures for selective introduction in defined sequence DNA and RNA molecules.

Synthesis of 1,N6-etheno-2'-deoxyadenosine, 3,N4-etheno-2'-deoxycytidine, and further chemistry on both deoxy and ribo series etheno nucleosides produces the corresponding phosphoramidites. These novel phosphoramidites are introduced selectively, quantitatively, and at specific positions at single or multiple sites into DNA or RNA sequences. The purification and chemistry involved in the synthesis of these products has been optimized to achieve the purity in excess of 99%. The resulting phosphoramidites were tested for their ability to couple and produce poly deoxy and ribonucleotides by solid phase chemistry. The coupling efficiency achieved was greater than 99% per step. Due to the instability of these etheno compounds in acidic and basic medium, various criteria to obtain pure oligomers have been established. The selective introduction of these fluorescent nucleosides into defined sequence DNA and RNA molecule will greatly facilitate the structure-function studies of various RNAs, protein-RNA structures, and DNA-RNA based diagnostics applications. The characteristic and high fluorescent intensity (detection below 1 x 10(-9) M for adenosine sites and below 1 x 10(-7) M for cytidine sites) is particularly suited for the biochemical and biological research and product development applications. The usefulness of these etheno containing modified sequences as sequencing and amplification primers is demonstrated by their full participation in polymerase chain reaction experiments.

Base Sequence↗
PubMed1994

Juvenile chronic arthritis in India: is it different from that seen in Western countries?

Medical records of 89 children with juvenile chronic arthritis attending the clinical immunology outpatient department of a tertiary care hospital were analysed. Polyarticular type of juvenile chronic arthritis was the most common, followed by pauciarticular and systemic onset types. No patient with the early onset pauciarticular disease subset, which is associated with iridocyclitis and antinuclear antibody (ANA) positivity was seen. Uveitis was observed in only one patient with late onset pauciarticular disease. The ANA positivity rate (1/89) was very low. Polyarticular onset type disease had a higher incidence of deformities.

Acute-Phase Proteins↗
PubMed1994

Serum IgM rheumatoid factor by enzyme-linked immunosorbent assay (ELISA) delineates a subset of patients with deforming joint disease in seronegative juvenile rheumatoid arthritis.

Using human IgG as an antigen in an enzyme-linked immunosorbent assay (ELISA), we looked for the presence of IgM rheumatoid factor (RF) in the sera of 74 children with juvenile rheumatoid arthritis (JRA). Nine children had RF detectable by both latex agglutination and ELISA. Forty-five percent (26 of 65) of the children who were seronegative by latex agglutination were found to be positive for IgM RF by ELISA. The prevalence of IgM RF was higher in patients with polyarticular onset disease (57.4%) than in those with pauciarticular onset (38.5%) or systemic onset (27.2%) disease. The prevalence of RF was higher in sera from patients with deforming joint disease than those without deformities (P < 0.01).

Adolescent↗
PubMed1994

Assembly of LamB and OmpF in deep rough lipopolysaccharide mutants of Escherichia coli K-12.

Assembly of the OmpF and LamB proteins was kinetically retarded in deep rough lipopolysaccharide mutants of Escherichia coli K-12. OmpF assembly was affected at the step of conversion of metastable trimers to stable trimers, whereas LamB assembly was influenced both at the monomer-to-metastable trimer and metastable-to-stable trimer steps. These assembly defects were reversed in the presence of the sfaA1 and sfaB3 suppressor alleles, which were isolated by using ompF assembly mutants.

Bacterial Outer Membrane Proteins↗
PubMed1994

Effective control of cisplatin induced emesis by combination drug regimen.

Thirty two cycles of chemotherapy were administered to sixteen patient containing 50-75 mg/msq. of cisplatin. For antiemetic prophylaxis, each patient received metoclopramide alone in the first cycle and a combination of metoclopramide + dexamethasone + lyrazepam in the next cycle. Effective control of emesis was achieved in 81% cycles on the combination antiemetic regime as compared to 19% on MCP alone. There was no statistical difference in the relief of nausea by the two regimens.

Adult↗