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Biomedical subjects

V Dev

Publications and source records attributed to V Dev.

At least 73 records · Page 4Linked to original sources
PubMed1988

Quantitative grading of exercise stress test for patients with coronary artery disease using multivariate discriminant analysis.

A group of 111 male patients who had undergone maximal or symptom-limited maximal exercise stress testing for evaluation of coronary artery disease (CAD) were subjected to coronary angiography. Group I comprised 33 patients with normal or single-vessel disease (SVD), while 78 patients with double-vessel disease (DVD) or triple-vessel disease (TVD) formed Group II. On univariate analysis of the exercise test, the following variables were found to be of significance in discriminating between the two groups: age, exercise duration, double product (heart rate X systolic blood pressure) at peak exercise, duration of ST-segment depression, number of leads showing ST depression, ST depression of 1 mm or more, configuration of the depressed ST segment, and diastolic blood pressure response to exercise. Multivariate analysis however revealed that only the following five variables had significant discriminant power: number of leads showing ST depression, exercise duration, double product, diastolic pressure response, and ST-segment configuration. On the basis of their relative importance, a regression equation was developed to give a quantitative score to individual patients. A score of less than zero detected multivessel disease (MVD) with high specificity (94%) and sensitivity (70%), while a score of 15 or more almost excluded MVD (sensitivity 87%). The scoring system as reported here improved the exercise stress test interpretation when compared with the conventional reporting system.

Adult↗
PubMed1988

Association of coronary calcification with obstructive disease in coronary arteries in Indian patients.

A total of 1150 consecutive patients (1052 males and 98 females; age 51.2 +/- 10.1 years) with suspected coronary artery disease (Group I) were subjected to fluoroscopy for detection of coronary artery calcification (CAC) and coronary angiography. Another group (Group II) of 120 patients (95 males and 25 females; age 51.4 +/- 9.4 years) catheterized for cardiac diseases other than coronary artery disease (CAD) were subjected to the same protocol of fluoroscopy and coronary angiography to exclude incidental CAD in view of their age. CAC was present in 240 patients (20.0%) in Group I. Of these, 200 (83.4%) had triple-vessel disease (TVD); 20 (8.3%) had double-vessel disease (DVD); 19 (7.9%) had single-vessel disease (SVD); and 37 (15.4%) patients had left main coronary disease (LMCAD). Only one of these patients had insignificant CAD considered as "normal" coronary arteries (NC). Incidence of LMCAD, TVD, DVD, SVD, and NC in patients without CAC was 4.4%, 56.3%, 18.2%, 14.0%, and 11.5%, respectively. Incidence of CAC in patients with LMCAD, TVD, DVD, SVD, and NC was 48.1%, 28.1%, 10.8%, 13.0%, and 1.0% respectively. In Group II (n = 120), 24 patients (20%) had CAD, CAC was present in 5 patients with CAD (20.9%), and in two patients without CAD (2%). CAC is relatively uncommon in Indian CAD patients. Its presence, however, indicates severe multivessel disease.

Adult↗
PubMed1988

Partial anomalous pulmonary venous drainage and intact atrial septum with mitral stenosis: the paradox of a small shunt.

Clinical, hemodynamic, and angiographic features of 10 patients with partial anomalous pulmonary venous drainage, intact atrial septum, and rheumatic mitral stenosis have been presented. Seventeen patients with this combination of anomalies reported in the literature have also been reviewed. The clinical diagnosis of mitral stenosis was possible in each of our 10 cases. Partial anomalous pulmonary venous drainage and intact atrial septum in addition to mitral stenosis was clinically suspected in only four patients. The findings suggesting additional presence of partial anomalous pulmonary venous drainage and intact atrial septum in a patient with mitral stenosis include: wide variable splitting of the second sound, pulmonary ejection systolic murmur with or without a thrill, and radiological evidence of unilateral increase in pulmonary vascularity or unilateral hilar pulsations. Hemodynamic findings were characterized by a relatively modest left to right shunt (Qp/Qs:2.2 +/- 1.4). Elevated pulmonary vascular resistance was found in the anomalously draining as well as the normally draining lung segments (9.1 +/- 4.9 and 6.5 +/- 3.4 units, respectively, t = 1.32;NS). The mechanism of the unexpected high resistance in the anomalously draining lung segments permitting only a small left to right shunt is discussed.

Adolescent↗
PubMed1988

Concurrent balloon dilatation of tricuspid and calcific mitral valve in a patient of rheumatic heart disease.

Concurrent percutaneous balloon dilatation of the mitral and tricuspid valve was performed in a 21-year-old female with severe rheumatic calcific mitral stenosis and severe tricuspid stenosis. The mean gradient across the mitral valve decreased from 30 mm Hg to an immediate post-dilatation level of 14 mm Hg and the mitral valve area increased from 0.71 cm2/m2 to 1.2 cm2/m2. The mean gradient across the tricuspid valve decreased from 11.5 mm Hg to 5 mm Hg. Hemodynamic improvement was maintained at a repeat study performed eight days later. Palliative balloon dilatation of two valves, concurrently performed, thus saved the patient from an open heart procedure and a possible valve replacement.

Adult↗
PubMed1988

Evaluation of patients with bundle branch block and "unexplained" syncope: a study based on comprehensive electrophysiologic testing and ajmaline stress.

Thirty-five patients with bundle branch block (BBB) and unexplained syncope underwent electrophysiologic study (EPS) including programmed ventricular stimulation and ajmaline administration (1 mg/kg, IV) to induce infra-His block. A prolonged HV interval (greater than 55 ms) was present in 16 of the 35 patients. Ajmaline-induced HV block occurred in 12 patients (complete HV block in 10, and 2:1 HV block in two). Monomorphic ventricular tachycardia (VT) was inducible in nine (25.7%) and polymorphic VT in two patients (5.7%). Left ventricular ejection fraction (LVEF) was less than 40% in five patients (45.5%) with inducible VT. Two patients had an unexpected co-existence of inducible HV block and VT. The remaining 14 patients (40%) had no detectable abnormality. The incidence of inducible VT was higher (45% vs 13.3%), and the presence of negative studies was lower (30% vs 53.3%) in patients with structural heart disease (n = 20), when compared to those with no significant heart disease (n = 15) (differences not significant [NS]). During a mean follow-up period of 16.5 +/- 9.2 months, all the patients with inducible HV block have been asymptomatic after having received permanent pacemakers. Patients with inducible monomorphic VT (except one with poor left ventricular function who died suddenly) have also been asymptomatic on antiarrhythmic drugs. Of the remaining patients, seven with normal EPS, two with prolonged HV intervals but no inducible HV block (despite being given permanent pacemakers) and one patient with polymorphic VT on antiarrhythmic drugs continue to have recurrent syncope. Approximately 60% of patients with BBB and unexplained syncope have clinically significant electrophysiologic abnormalities.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
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↗