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Biomedical subjects

V Dev

Publications and source records attributed to V Dev.

At least 91 records · Page 5Linked to original sources
PubMed1987

Coronary arteritis in nonspecific aortoarteritis.

Nonostial distal coronary artery involvement in nonspecific aortoarteritis is rare. We report a 35-year-old patient with features of nonspecific aortoarteritis who had an inferolateral myocardial infarction and on coronary angiography was shown to have severe disease of the left circumflex artery in its middle third.

Adult↗
PubMed1987

Ajmaline induced intra-Hisian block.

Ajmaline-induced block within the atrioventricular bundle (intra-Hisian) is rare. We report a 59-year-old male with a left bundle branch block in whom intravenous Ajmaline unmasked a latent conduction abnormality within the atrioventricular bundle. Relevant literature is reviewed.

Ajmaline↗
PubMed1986

Double isotype production by a neoplastic B cell line. II. Allelically excluded production of mu and gamma 1 heavy chains without CH gene rearrangement.

In our accompanying paper, we described a switch variant (BCL1.2.58) that expresses membrane and secreted forms of IgM and IgG1. Both IgM and IgG1 share the same idiotype and use the same VDJ rearrangement. Here, a detailed Southern blot analysis of the entire constant region of the Ig heavy chain (Ig CH) locus of parental (BCL1.B1) and variants (BCL1.B2) DNA showed no detectable rearrangement. Similar analysis of the JH-C mu region led to the conclusion that two heavy chain alleles present in the IgM/IgG1-producing variants carried the same VDJ rearrangement but differed in their 3' flanking regions. One chromosome 12 did not carry any Ig CH genes, whereas, the other chromosome 12 carried one copy of CH genes. In BCL1.B1, however, each of the chromosome 12 alleles carried a full copy of CH genes. Karyotypic analysis confirmed the presence of two translocated t(12;16) chromosomes in both BCL1.2.58 and BCL1.B1 cells, with a break 5' to the VH locus at the distal region (12F2) of chromosome 12, and at the proximal region below the centromere (16B3) of chromosome 16. We conclude that double production of IgM and IgG1 in BCL1.B2 is accomplished by transcription of the corresponding CH genes in germline configuration using a single VDJ on the same chromosome 12.

Alleles↗
PubMed1985

Genetic relationships among certain species of the Aedes (Stegomyia) scutellaris group (Diptera: Culicidae).

Genetic affinities between species of the Aedes (Stegomyia) scutellaris group were determined through experimental hybridization. In this investigation Aedes hebrideus and Ae. scutellaris katherinensis were reciprocally crossed with Ae. polynesiensis, Ae. pseudoscutellaris, Ae. kesseli, Ae. malayensis, Ae. alcasidi and Ae. albopictus. Data on insemination and egg hatch rates were recorded in the reciprocal crosses. Of these, Ae. hebrideus and Ae alcasidi, Ae. hebrideus and Ae. s. katherinensis, Ae. malayensis and Ae. hebrideus, and Ae. malayensis and Ae. s. katherinensis, were unidirectionally compatible using female parent of former species of the two. The reciprocal crosses of these laid infertile eggs. Aedes s. katherinensis and Ae. alcasidi were bidirectionally compatible. All other interspecific crosses were incompatible producing infertile eggs. In the compatible crosses, i.e. where the viable hybrids were obtained, F2 and hybrid fertilities were determined. Species hybrids obtained by crossing Ae. malayensis females and Ae. s. katherinensis males yielded lower fertility in F2 and differential fertility when backcrossed. Species hybrids obtained by crossing Ae. s. katherinensis females and Ae. alcasidi males resulted in lower fertility in F2 and also when backcrossed to Ae. s. katherinensis females. All other species hybrids were fertile. Based on the data obtained, Ae. hebrideus, Ae. s. katherinensis, Ae. malayensis and Ae. alcasidi formed a sub-grouping which showed remote genetic affinities individually or as a group with rest of the species investigated.

Aedes↗
PubMed1981

Correlation of double-minute chromosomes with unstable multidrug cross-resistance in uptake mutants of neuroblastoma cells.

A series of increasingly drug-resistant cell populations were selected and cloned from C-46 murine neuroblastoma with the chemotherapeutic drugs maytansine, vincristine, adriamycin, or Baker's antifol. All clones demonstrated reciprocal cross-resistance to these structurally and functionally diverse drugs and failed to accumulate radiolabeled vincristine, colchicine, or Baker's antifol despite normal drug binding to cell homogenates. Initial isolates of drug-resistant populations were genetically unstable, rapidly reverting to a drug-sensitive phenotype when grown without drug, at 0.05 reversion per cell division. After prolonged growth in drug, this drug-resistant genotype stabilized. Mean chromosome number increased 300% in an initially isolated 20-fold maytansine-resistant clone, which also displayed numerous double-minute chromosomes. Descendants 240-fold more resistant than the parent, also unstable, possessed the wild-type complement of 80 chromosomes, but 45% of these cells possessed 24 double-minute chromosomes per cell; such chromosomes were absent from the drug-sensitive parental clone. Only 1.0 and 1.2 double-minute chromosomes per cell were seen in a 7-fold stably resistant revertant or 1200-fold stably resistant descendants, respectively. Double-minute chromosomes containing amplified genes for the drug target dihydrofolate reductase (tetrahydrofolate dehydrogenase; 5,6,7,8-tetrahydrofolate:NADP+ oxidoreductase, EC 1.5.1.3) have been reported in an unstable methotrexate-resistant R1-A sarcoma. These extrachromosomal gene copies were absent in stably resistant progeny. The presence of similar particles in unstably drug-resistant uptake mutants of neuroblastoma and their diminution in stably resistant descendants supports and extends their possible role in the rapid onset and instability of epigenetic drug resistance in cancer chemotherapy.

Animals↗
PubMed1977

A photomap of the salivary gland chromosomes of Anopheles stephensi liston (Culicidae: Diptera).

A photomap of the banding pattern of the salivary gland chromosomes of Anopheles stephensi Liston, which is first of its kind, has been prepared. The salivary chromosome complement consists of five arms, the shortest of which represents the telocentric X-chromosome, and the remaining four the autosomal arms. A comparison has been made of the banding pattern of this species with other species of the subgenus Cellia.

Animals↗