Percutaneous balloon dilatation of aortic coarctation in adults.
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Adult↗
Biomedical subjects
J Gupta
Publications and source records attributed to J Gupta.
Human telomerase RNA and telomerase activity in immortal cell lines and tumor tissues.
Telomerase activity has been detected in many human immortal cells lines and in tumor tissues, whereas it is generally absent from primary cell strains and from many tumor adjacent tissue samples. With the recently cloned human telomerase RNA (hTR), we used Northern analysis to follow the levels of hTR in primary, precrisis, and immortalized cells. It was surprising that the amount of hTR was high in cell strains that lacked telomerase activity, and the levels did not parallel the increases in telomerase activity, which accompanies immortalization. In addition, although the hTR levels were somewhat higher in tumor samples compared to nontumor tissues, the level of hTR in a variety of different human tumors did not predict the level of telomerase activity in the tumor. Thus, whereas hTR was detected in all samples that have telomerase activity, the presence of the RNA was not a good predictor of the presence or amount of telomerase activity.
B-Lymphocytes↗
Sarcoid heart disease: a rare cause of chest pain and malignant cardiac arrhythmia in a young Asian man. A case report.
Cardiac sarcoidosis is a disease of young adults. In most cases, it presents with sudden death, arrhythmia, conduction disorders, heart failure, or cardiomyopathy. The authors describe a young Indo-Asian man with cardiac sarcoidosis who presented acutely with chest pain and malignant cardiac arrhythmias. The diagnosis of cardiac sarcoidosis should be considered in all young patients with unexplained arrhythmias or heart failure or in cases of sudden death.
Adult↗
Telomere elongation in immortal human cells without detectable telomerase activity.
Immortalization of human cells is often associated with reactivation of telomerase, a ribonucleoprotein enzyme that adds TTAGGG repeats onto telomeres and compensates for their shortening. We examined whether telomerase activation is necessary for immortalization. All normal human fibroblasts tested were negative for telomerase activity. Thirteen out of 13 DNA tumor virus-transformed cell cultures were also negative in the pre-crisis (i.e. non-immortalized) stage. Of 35 immortalized cell lines, 20 had telomerase activity as expected, but 15 had no detectable telomerase. The 15 telomerase-negative immortalized cell lines all had very long and heterogeneous telomeres of up to 50 kb. Hybrids between telomerase-negative and telomerase-positive cells senesced. Two senescent hybrids demonstrated telomerase activity, indicating that activation of telomerase is not sufficient for immortalization. Some hybrid clones subsequently recommenced proliferation and became immortalized either with or without telomerase activity. Those without telomerase activity also had very long and heterogeneous telomeres. Taken together, these data suggest that the presence of lengthened or stabilized telomeres is necessary for immortalization, and that this may be achieved either by the reactivation of telomerase or by a novel and as yet unidentified mechanism.
Base Sequence↗
Telomerase activity in normal leukocytes and in hematologic malignancies.
Telomeres are essential for function and stability of eukaryotic chromosomes. In the absence of telomerase, the enzyme that synthesizes telomeric DNA, telomeres shorten with cell division, a process thought to contribute to cell senescence and the proliferative crisis of transformed cells. We reported telomere stabilization concomitant with detection of telomerase activity in cells immortalized in vitro and in ovarian carcinoma cells, and suggested that telomerase is essential for unlimited cell proliferation. We have now examined the temporal pattern of telomerase expression in selected hematologic malignancies. We found that, unlike other somatic tissues, peripheral, cord blood, and bone marrow leukocytes from normal donors expressed low levels of telomerase activity. In leukocytes from chronic lymphocytic leukemia (CLL) patients, activity was lower than in controls in early disease, and comparable with controls in late disease. Relative to bone marrow, telomerase activity was enhanced in myelodysplastic syndrome (MDS) and more significantly so in acute myeloid leukemia (AML). Regardless of telomerase levels, telomeres shortened with progression of the diseases. Our results suggest that early CLL and MDS cells lack an efficient mechanism of telomere maintenance and that telomerase is activated late in the progression of these cancers, presumably when critical telomere loss generates selective pressure for cell immortality.
Acute Disease↗
Recurrent myocardial infarction with angina and normal coronary arteries.
Although it is well recognised that patients with ischemic heart disease can have normal coronary arteries on coronary angiography, most such patients have angina pectoris, whilst a minority have had a previous myocardial infarction. There are few reports of patients with recurrent myocardial infarctions and angina, but with normal coronary arteries on coronary angiography. We describe six patients who had more than one myocardial infarction, confirmed by raised cardiac enzymes and changes on the electrocardiogram. They subsequently developed classical angina and subsequent coronary angiography demonstrated no atherosclerotic coronary artery disease. Coronary artery spasm and diminished coronary reserve may have been contributory factors in these patients.
Adult↗
Multivessel coronary angioplasty with anomalous origin of the left main coronary artery.
We report a case of coronary angioplasty to the right coronary artery, the circumflex, and the left anterior descending artery in a patient with anomalous left main coronary artery arising from the right aortic sinus of Valsalva. At angiographically documented follow-up of more than 2 years, the patient remains well without restenosis. This case represents the only such report in the literature. Angioplasty hardware was an important factor in successful crossing and dilatation of multiple severe and distal stenoses in the anomalous left system; appropriate technical details are discussed.
Angioplasty, Balloon, Coronary↗
Interaction of organophosphorus insecticides phosphamidon & malathion on lipid profile & acetylcholinesterase activity in human erythrocyte membrane.
The organophosphorus insecticides phosphamidon and malathion were found to inhibit the activity of human acetylcholinesterase in vitro, in the human erythrocyte membrane. Lineweaver-Burk analysis indicated that the insecticide induced inhibition of acetylcholinesterase activity was uncompetitive in nature. The total lipid, cholesterol and phospholipid contents of erythrocyte membranes were reduced following phosphamidon and technical malathion treatment, while the level of lipid peroxidation was raised following malathion treatment.
Acetylcholinesterase↗
Partial characterization of protein kinase C from an insect cell line.
The characteristics of protein kinase C (EC 2.7.1.37) from an insect cell line (Choristoneura fumiferana) have been described. DEAE-cellulose chromatography produced a major peak of activity which eluted at 0.04-0.055 M NaCl. The enzyme was sensitive to phosphatidylserine in the presence of calcium. Phorbol 12-myristate 13-acetate (PMA) in nanomolar concentrations stimulated protein kinase C activity 8-fold over basal levels and reduced the enzymes requirement for Ca2+. The enzyme had a Ka of 10 nM for PMA. Diacylglycerols tested included diolein, dilinolein, diarachidonin, oleoyl-acetyl-glycerol, dioctonoyl-sn-glycerol, dipalmitin and distearin. A 2.5- to 3-fold activation was obtained in the presence of 26 microM diolein, 40 microM oleoyl-acetyl-glycerol and 46 microM dioctonoyl-sn-glycerol. The enzyme activity was sensitive to the inhibitor H-7 and 50% inhibition was achieved at a concentration of 52 microM H-7. Phosphatidylinositol enhanced enzyme activity in the absence of phosphatidylserine but phosphatidylethanolamine had no effect.
Animals↗
Evidence that the middle T antigen of polyomavirus interacts with the membrane skeleton.
The transforming protein of polyomavirus, middle T antigen, is associated with cellular membranes. We have examined the subcellular location of the middle T antigen in two different cell types by fractionation and detergent phase partitioning. Middle T antigen expressed in human cells by a recombinant adenovirus was detected primarily in the membrane skeleton. Sucrose gradient fractionation revealed that the middle T antigen was associated with complexes with molecular weights of 500,000 to 1,000,000. Several markers for cytoskeleton cofractionate with these complexes, including actin, tubulin, and vimentin. Electron micrographs of membrane skeleton prepared from cells expressing middle T antigen demonstrated that this material contained primarily fibrous structures and was clearly devoid of bilayer membranes. These structures were distinct from the filamentous structures observed in fractions enriched for cytoskeleton. Consistent with a role for membrane skeleton localization in transformation, middle T antigen was detected exclusively in fractions enriched for membrane skeleton in middle T antigen-transformed Rat-2 cells. Our results may resolve the apparent difference between middle T antigen localization as determined by immunomicroscopy and that determined by subcellular fractionation.
Antigens, Polyomavirus Transforming↗
Protective role of metallothionein in nickel induced oxidative damage.
Recent studies have focussed on the role of thiol rich proteins especially metallothionein (MT) in the therapeutic interventions against oxidative damage. In our previous communication we showed that reactive oxygen species arising via Fenton's reactions are the proximal lipid oxidant during nickel-toxicity. The purpose of the present communication is to evaluate the role of zinc, cadmium or silver-metallothioneins on the protection against nickel-induced peroxidative damage. Our results demonstrate that Zn-MT provided maximum protection against nickel-induced mortality in mice and also served as an efficient antagonist in inhibiting nickel-mediated lipid peroxidation compared to Cd-MT or Ag-MT. Zn-MT also provided protection against iron (II)-ascorbate induced microsomal lipid peroxidation and reversed nickel-mediated inhibition of calcium sequenstration. We conclude that Zn-MT could serve as an excellent physiological antioxidant against nickel-mediated oxidative.
Animals↗
Human plasma low density lipoprotein: a fluorescence study.
Hydrophobic nature of human plasma low density lipoprotein surface has been studied by fluorescence spectroscopic method. Enhancement in 8-anilino-1-naphthalene sulphonate (ANS) fluorescence quantum yield from 0.004 to 0.114 at 470 nm has suggested that the ANS binding sites are fairly low in polarity. LDL has been found to have 77 homogeneous binding sites for ANS (Ka = 2.5 x 10(5) M-1). The binding of an ANS molecule does not affect the successive binding sites. Variation in temperature from 15 degrees to 45 degrees C did neither alter the number of binding sites nor association constant. Quenching of protein fluorescence (lambda exc 286 nm, lambda ems 336 nm) indicated the occurrence of energy transfer in LDL-ANS complex arising from conformational changes capable of bringing charge acceptor segments near to other ANS site. About 30-fold increase in ANS quantum yield and large shift in the emission maximum are characteristic features of large hydrophobic environment on the surface of LDL particle.
Anilino Naphthalenesulfonates↗
Effect of malathion on antioxidant defence system in human fetus--an in vitro study.
Malathion under in vitro condition even at lower concentration (250 ppm) altered the level of enzymes associated with glutathione cycle and antioxidant defence system in human fetal brain and liver. Such changes involved alterations in glutathione status and extent of lipid peroxidation. The inhibitory effect of malathion was dose dependent in case of human fetal brain and was more vulnerable than fetal liver. This alteration (inhibition or activation) was maximum in case of tissues from fetuses of early period of development, suggesting greater susceptibility of human fetus towards this organophosphorus insecticide.
Age Factors↗
Effects of organophosphorus insecticide phosphomidon on antioxidant defence components of human erythrocyte and plasma.
Effect of organophosphorus insecticide, phosphomidon (250 and 500 ppm) on human erythrocyte and plasma were studied in vitro to get insight into the cellular antioxidant defence mechanism and malondialdehyde formation. The antioxidant defence system of erythrocyte was altered as evident by depression of glutathione reductase, glucose 6 phosphate dehydrogenase, whereas the level of reduced glutathione, glutathione peroxidase, glutathione-S-transferase, superoxidedismutase and catalase were stimulated. In the case of plasma fraction, glutathione reductase, glutathione peroxidase, glutathione-s-transferase, glucose-6-phosphate dehydrogenase, superoxide dismutase and levels of reduced glutathione were significantly depressed and the malondialdehyde formation and catalase activity were elevated indicating the less adaptive response of plasma to protect it from oxidative damage.
Adult↗
Conjugated dienes in lipids of apolipoprotein B containing lipoproteins of normal and type 2 (non-insulin-dependent) diabetic patients.
Conjugated dienes present in the fatty acyl chains of cholesterol esters and triglycerides associated with plasma apolipoprotein B containing lipoproteins of normal and Type 2 (non-insulin-dependent) diabetic patients (n = 17) have been analysed using second derivative electronic absorption spectroscopy. Characteristic spectral patterns for both normal subjects and Type 2 diabetic patients were observed. Cis, trans and trans, trans conjugated dienes in cholesterol esters of lipoprotein B of Type 2 patients and normal subjects were found to be 41.74 +/- 0.51 mg/litre, 8.20 +/- 0.20 mg/litre (p less than 0.01) and 24.70 +/- 0.33 mg/litre, 9.22 +/- 0.06 mg/litre (p less than 0.01), respectively. Levels of these dienes in triglyceride fraction were 21.21 +/- 0.52 mg/litre, 7.72 +/- 0.02 mg/litre (p greater than 0.05) and 15.49 +/- 0.36 mg/litre, 7.91 +/- 0.11 mg/litre (p greater than 0.05), respectively.
Adult↗
Nucleophilic scission of thioester linkages and conformational changes in human plasma low density lipoproteins.
A comparison between conformations of native and methylamine modified human plasma low density lipoproteins (hydrated density 1.032-1.043 g/ml) has been presented. Near UV circular dichroism and difference absorption spectra of modified low density lipoprotein have suggested substantial differences in the local environments of several aromatic amino acid side chains. Relatively lower ellipticity at 222 nm of modified lipoprotein indicated alterations in the secondary structures of its protein moiety. Nucleophilic reaction of methylamine did not cause the peptide bond scission but it brought conformational transition such that some of the buried hydrophobic domains of the protein moiety got exposed to the aqueous environment.
Apolipoproteins B↗
Predicting low birth weight delivery using maternal nutritional and uterine parameters.
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Anthropometry↗
Some physicochemical properties of human milk bile-salt activated lipase.
Influence of pH, deoxycholate and denaturing reagents on human milk bile-salt activated lipase (EC 3.1.1.3) has been studied. It appears that pH between 5.0-8.0 has no significant effect on the secondary structure of this lipase, but its higher order structures are affected. Lipase-dependent 8-anilino-1-naphthalene sulphonate fluorescence has revealed that the deoxycholate activated form of lipase has a surface rich in hydrophobic amino acid residues. Circular dichroism and second derivative electronic absorption spectroscopic observations have also provided an evidence for deoxycholate-induced alterations in the surface conformation of this lipase.
Bile Acids and Salts↗