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Biomedical subjects

S Chandra

Publications and source records attributed to S Chandra.

At least 145 records · Page 8Linked to original sources
PubMed1994

Percutaneous transvenous mitral commissurotomy in 390 cases using the Inoue balloon catheter.

Percutaneous transvenous mitral commissurotomy using the Inoue technique was performed in 390 cases of rheumatic mitral stenosis. There were 220 (56%) females and 170 (44%) males. The age range was 9-47 years [mean +/- S.D., 26 +/- 14) and all were symptomatic (New York Heart Association (NYHA) class II in 23 (6%); class III in 280 (72%); and class IV in 87 (22%) patients]. Mitral valve area increased from 0.6 +/- 0.4 to 2 +/- 0.7 cm2, mean transmitral gradients decreased from 26 +/- 8 to 5 +/- 3 mmHg and cardiac index improved from 2.2 +/- 0.8 to 3.0 +/- 0.7 l/min/m2 (P < 0.001). There were no procedure related deaths. An increase in mitral regurgitation by one grade was observed in 40 (10%) cases, with 8 (2%) cases developing severe mitral regurgitation. Oximetry evidence of left to right atrial shunt (Qp/Qs > or = 1.5:1) was observed in 11 (3%) patients. Four (1.0%) patients developed cardiac tamponade, none had thromboembolism. Follow-up of 290 cases at 26 +/- 5 weeks showed persistent improvement in clinical (NYHA class I in 98%) and echocardiographic mitral valve area. Percutaneous transvenous mitral commissurotomy is safe, easy to perform and provides excellent clinical and hemodynamic benefit in the majority of cases.

Adult↗
PubMed1994

Comparison of dobutamine infusion and exercise during radionuclide ventriculography in the risk stratification after acute myocardial infarction.

Forty-eight patients with acute myocardial infarction were subjected to radionuclide ventriculography during exercise and dobutamine infusion after a mean duration of 25 +/- 18 days following acute myocardial infarction. The results were compared and correlated with coronary angiography. Two patterns of abnormal response of radionuclide ventriculography were identified: (1) a worsening of the baseline wall motion abnormality confined to the infarcted area, and (2) fresh regional wall motion abnormalities in areas with normal motion at rest. Of 44 patients with significant coronary artery lesions (> or = 70% diameter stenosis), 18 had single vessel disease and 26 had multivessel disease. Dobutamine and exercise radionuclide ventriculography identified 23 and 21, respectively, of 26 multivessel disease patients yielding sensitivities of 88% and 80%. Seven of 18 single vessel disease patients showed a worsening of baseline wall motion abnormality of infarct area on dobutamine infusion radionuclide ventriculography. Subgroup analysis of coronary angiograms of single vessel disease revealed that 10 of 18 patients had subtotal occlusion of infarct-related artery supplying a hypokinetic area and the rest had a totally occluded coronary artery supplying an akinetic area. Dobutamine infusion and exercise radionuclide ventriculography detected 7 and 6 of these 10 patients implying the presence of jeopardized myocardium in infarcted/peri-infarct area. Dobutamine stress radionuclide ventriculography is an acceptable alternative to exercise testing to stratify risk following acute myocardial infarction.

Coronary Angiography↗
PubMed1994

Elimination of infection in pulpectomized deciduous teeth: a short-term study using iodoform paste.

This study was conducted to retain the pulp-involved deciduous teeth in dental arches and were restored to function by elimination of infection in pulpectomized deciduous teeth using iodoform paste. Clinically the teeth were evaluated for pain, mobility, and presence or absence of sinus for 3 months. We concluded that the iodoform paste is a suitable root canal filling material for single-visit pulp canal treatment in chronic pulp-infected deciduous teeth.

Anti-Infective Agents↗
PubMed1994

Ion microscopy in biology.

Ion microscopy, a mass spectrometry based isotopic imaging technique, is uniquely suited for ion transport related problems in biological systems. Due to its high sensitivity, it can image the transport and distribution of both major and minor elements (isotopes) at subcellular resolutions. The images of major elements such as K, Na, CI, etc., can be viewed directly and recorded in real-time from the microchannel plate-fluorescent screen detector of the instrument. The low concentration physiologically important elements, such as Ca, need about one minute of integration for good quality imaging. The isotopic imaging capability of ion microscopy provides a unique approach for the use of stable isotopes as tracers. In this way, one can image both the endogenous and the transported isotopes independently. Strict cryogenic sample preparations are essential for ion transport studies. Correlative imaging of the same cell with laser scanning confocal microscopy and ion microscopy can positively identify smaller cytoplasmic compartments such as the Golgi apparatus in calcium images. We have identified the Golgi apparatus as a calcium storing organelle. Another unique application of ion microscopy is the imaging of boron from boronated drugs used in Boron Neutron Capture Therapy (BNCT) of cancer. Ion microscopy is capable of rapid screening of potential drugs for BNCT. This critical information is essential for the fundamental understanding of BNCT. Ion microscopy is now at the stage where it can provide previously unattainable answers to important biomedical questions.

Animals↗
PubMed1994

Percutaneous transvenous mitral commissurotomy using Inoue catheter in juvenile rheumatic mitral stenosis.

Percutaneous transvenous mitral commissurotomy (PTMC) using Inoue balloon was performed in 270 patients with rheumatic mitral stenosis. Of these 81 (27%), 48 males and 33 females, had juvenile mitral stenosis (age < 20 years, range 9-20 years mean 14 +/- 5). All patients were symptomatic (New York Heart Association [NYHA] class III in 61 patients and class IV in 20 patients). Following PTMC, the mitral valve area (MVA) increased from 0.8 +/- 0.4 to 2.2 +/- 0.5 cm2 (P < 0.001) and the cardiac index increased from 2.4 +/- 0.8 to 3.0 +/- 0.8 L/min/m2 (P < 0.001). Mean transmitral gradients decreased from 24 +/- 8 to 4 +/- 3 mm Hg (P < 0.001). Three (4%) patients had an increase in mitral regurgitation by 1 grade (grade 2/4); however, none required surgery. Significant left to right atrial shunt (Qp/Qs > 1.3: 1) on oximetry was detected in 8 (10%) patients. Overall results were compared to those with adult subgroup of patients with rheumatic mitral stenosis (n = 189, 100 females and 89 males), who underwent PTMC simultaneously. Their age ranged from 21 to 44 years (mean 32 +/- 11 years). The percentage increase in MVA was higher in juvenile as compared to adult patients (172 +/- 61 vs. 154 +/- 69, respectively, P < 0.01). A larger final MVA was achieved in the juvenile group (2.2 +/- 0.5 vs. 1.9 +/- 0.3 cm2, P < 0.05). However, the incidence of increase in mitral regurgitation by 1 grade was similar in two groups (6% vs. 4%, P = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

An Na+/K(+)-ATPase inhibitor protein from rat brain cytosol.

A protein isolated from rat brain cytosol is found to inhibit Na+/K(+)-ATPase in rat brain and kidney and H+/K(+)-ATPase from toad gastric mucosa, but has no effect on Ca2+,Mg(2+)-ATPase and Ca(2+)-ATPase isolated either from rat testis or goat spermatozoa. The inhibitor has been partially purified by ammonium sulphate precipitation followed by gel-filtration through Sephadex G-100. The inhibitor seems to bind at or close to the ATP binding site of Na+/K(+)-ATPase, such that the binding of the inhibitor to ATPase is reversible and competitive in nature with respect to the substrate. Optimum inhibition is observed at around the phase transition temperature of brain Na+/K(+)-ATPase and the inhibitory activity is only partially dependent on -SH or -NH2 group(s) of the inhibitor protein.

Animals↗
PubMed1993

Purification and sequencing of radish seed calmodulin antagonists phosphorylated by calcium-dependent protein kinase.

A family of radish (Raphanus sativus) calmodulin antagonists (RCAs) was purified from seeds by extraction, centrifugation, batch-wise elution from carboxymethyl-cellulose, and high performance liquid chromatography (HPLC) on an SP5PW cation-exchange column. This RCA fraction was further resolved into three calmodulin antagonist polypeptides (RCA1, RCA2, and RCA3) by denaturation in the presence of guanidinium HCl and mercaptoethanol and subsequent reverse-phase HPLC on a C8 column eluted with an acetonitrile gradient in the presence of 0.1% trifluoroacetic acid. The RCA preparation, RCA1, RCA2, RCA3, and other radish seed proteins are phosphorylated by wheat embryo Ca(2+)-dependent protein kinase (CDPK). The RCA preparation contains other CDPK substrates in addition to RCA1, RCA2, and RCA3. The RCA preparation, RCA1, RCA2, and RCA3 inhibit chicken gizzard calmodulin-dependent myosin light chain kinase assayed with a myosin-light chain-based synthetic peptide substrate (fifty percent inhibitory concentrations of RCA2 and RCA3 are about 7 and 2 microM, respectively). N-terminal sequencing by sequential Edman degradation of RCA1, RCA2, and RCA3 revealed sequences having a high homology with the small subunit of the storage protein napin from Brassica napus and with related proteins. The deduced amino acid sequences of RCA1, RCA2, RCA3, and RCA3' (a subform of RCA3) have agreement with average molecular masses from electrospray mass spectrometry of 4537, 4543, 4532, and 4560 kD, respectively. The only sites for serine phosphorylation are near or at the C termini and hence adjacent to the sites of proteolytic precursor cleavage.

2S Albumins, Plant↗
PubMed1993

Reversal of chloroquine resistance in murine malaria parasites by prostaglandin derivatives.

An oligomeric ester of prostaglandin B2 (OC-5186) was found to reverse chloroquine resistance in the murine malarial parasite Plasmodium berghei. When mice were infected with either chloroquine-sensitive or -resistant P. berghei on day 0 (by intraperitoneal injection of 1 x 10(6) parasitized erythrocytes), they died before day 23. When treated with 15 mg/kg/day of chloroquine for the first four days of infection, all mice infected with the sensitive-strain survived, while all those infected with the resistant strain died before day 23. When OC-5186 (3-12 mg/kg/day) was administered in combination with chloroquine for the first four days, 60% of the animals infected with the resistant strain survived. The differences in the survival rate between the group treated with chloroquine only and the group treated with a combination of drugs (chloroquine plus 3-12 mg/kg/day of OC-5186) were significant. There was also a significant inhibition of parasitemia in the group treated with the combination of drugs. The combinations of chloroquine and a monomer ester of prostaglandin B2 (OC-5181) had some antimalarial activity, but the differences between the chloroquine-treated group and the combination treatment group were not significant in terms of both the parasitemia and the survival rate. Another oligomeric ester of prostaglandin E1 (MR-356) as well as unesterified monomer prostaglandins (PGA2 and PGB2) were ineffective by themselves and in combination with chloroquine.

Alprostadil↗
PubMed1992

The in vivo inhibition of transport enzyme activities by chloroquine in different organs of rat is reversible.

The antimalarial drug chloroquine is found to inhibit Na+, K(+)-ATPase, Ca2+, Mg(2+)-ATPase, Ca(2+)-ATPase, pNPPase and acetylcholinesterase activities in different organs of rat in vivo when injected for a certain periods of time. The inhibition seems to be due to the changes in the level of phospholipid, cholesterol and the fatty acid of the lipid and the alteration of the fluidity of the microsomal membranes. However, the enzyme activities return to the normal level in about 2-3 weeks after the discontinuation of the drug suggesting that the drug effect is reversible.

4-Nitrophenylphosphatase↗
PubMed1992

Nail-patella syndrome in a spontaneously aborted 18-week fetus: ultrastructural and immunofluorescent study of the kidneys.

Nail-patella syndrome (NPS), hereditary onycho-osteodysplasia, is an autosomal dominant disorder of nail dystrophy, patellar absence or hypoplasia, incomplete elbow extension, conical posterior iliac horns, and nephropathy. We studied the kidneys of an 18-week spontaneously aborted fetus of a mother with the NPS. Ultrastructural examination of the kidney showed thickening of the capillary walls of the glomeruli and mesangium. There was irregular thickening of basement membranes with subendothelial fibrillar electron-dense deposits. Immunofluorescence showed fibrinogen deposition in glomerular basement membranes. Fibrinogen deposition in utero may ultimately lead to glomerular fibrosis and intrabasement membrane collagen deposition as seen in the adult renal lesion of this syndrome. This is the first report of the NPS in which the renal abnormalities have been studied in a fetus. These findings provide support for possible prenatal diagnosis of NPS by intra-uterine kidney biopsy.

Abortion, Spontaneous↗