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Biomedical subjects

A Rastogi

Publications and source records attributed to A Rastogi.

At least 55 records · Page 3Linked to original sources
PubMed1993

Quantification of human plasma apolipoproteins C-I, C-II, and C-III by radioimmunoassays.

We have developed radioimmunoassays for the quantification of apolipoproteins (apo) C-I, C-II, and C-III in human plasma. The apo C proteins were isolated from very low-density lipoproteins of patients with hypertriglyceridemia, fractionated on a Sephacryl column, and purified by diethylaminoethyl cellulose anion-exchange chromatography followed by reverse-phase fast protein liquid chromatography. The assays were sensitive, specific, and reproducible, and the standards demonstrated parallel immunoreactivity with plasma samples. Patients with hypertriglyceridemia (triglyceride level more than 2,200 mg/liter)--14 patients with diabetes and 12 with type V hyperlipoproteinemia--were compared with age- and sex-matched control subjects. In comparison with the control groups, levels of apoproteins C-I, C-II, and C-III were significantly increased in both disease groups, but the ratios of the C peptides to triglycerides were significantly lower, an indication of a relative deficiency of C apoproteins in hypertriglyceridemic states. Independent radioimmunoassays for each of the C apolipoproteins would help to study their individual roles in triglyceride-rich lipoprotein metabolism.

Adult↗
PubMed1992

Hexachlorocyclohexane pesticides reduce survival and alter plasma membrane structure of Chinese hamster V79 cells.

We studied the cytotoxic effects of alpha-, beta-, gamma-, and delta-hexachlorocyclohexanes (HCCH) on the survival of Chinese hamster V79 cells using clonogenic assays. Lethal dose yielding 50% cell survival (LD50) suggests the following order of cytotoxicity: delta-(+)gamma-HCCH (LD50 4 micrograms/ml) (1:1, w/w, mixture) > delta-HCCH (LD50 6 micrograms/ml) > gamma-HCCH (LD50 13 micrograms/ml) > alpha-HCCH (LD50 approx. 35 micrograms/ml) >> beta-HCCH. Structural changes in plasma membranes prepared from HCCH-treated V79 cells at dose yielding 10% cell survival (LD10) were analyzed using Raman spectroscopy. Raman spectra of plasma membranes show bands at 2850, 2880-2890, and 2935 cm-1 in the C-H stretching region. The plot of the ratio (I2880-2890/I2850) vs temperature for control plasma membranes shows two transitions between -5 and 5 degrees C and between 12 and 20 degrees C. Plasma membranes prepared from gamma- and delta-HCCH-treated Chinese hamster V79 cells show single transitions between -4 and 11 degrees C and between -2 and 11 degrees C, respectively. These changes in the thermal transition properties suggest that both gamma- and delta-HCCH alter lipid and lipid-protein phases of the plasma membrane of V79 cells. Raman analysis of the amide I and amide III region spectra further suggest that delta-HCCH also alters the secondary structure and the environment of highly amidated segments of plasma membrane proteins. We suggest that the primary action of biologically active HCCH isomers is to disrupt the organization of the plasma membrane and that may affect cell viability.

Animals↗
PubMed1992

Apolipoprotein B quantified by particle-concentration fluorescence immunoassay.

We have developed a particle-concentration fluorescence immunoassay (PCFIA) for estimating apolipoprotein (apo) B concentrations in plasma. A two-step antigen-detection system with a polyclonal antibody to apo B bound to carboxyl-polystyrene particles binds the antigen, and a fluorescein-labeled monoclonal antibody detects the bound apo B. Narrow-cut low-density lipoproteins (d = 1.03-1.05 kg/L) were used as the primary standard. The assay compares well with the enzyme-linked immunosorbent assay. The PCFIA gives parallel responses with low-density lipoprotein, very-low-density lipoproteins, and plasma samples, and can be fully automated and completed in 3 h. In a pilot study of patients with diabetes, coronary artery disease (CAD), or both, we found statistically significant differences in apo B concentrations for patients with both CAD and diabetes compared with those for patients with diabetes alone or for control subjects (P < 0.01).

Apolipoproteins B↗
PubMed1991

Serum alpha-1 acid glycoprotein levels in acute idiopathic anterior uveitis.

Serum alpha-1 acid glycoprotein levels were measured in 56 patients with acute idiopathic anterior uveitis and 42 healthy subjects by a radial immunodiffusion method. The levels were found to be increased significantly in moderate and severe types of uveitis; they were normal in mild type. Serum alpha-1 acid glycoprotein levels closely paralleled the severity of the disease. The serum levels of this protein returned to normal after clinical improvement.

Acute Disease↗
PubMed1990

Organic pesticides modify lipid-lipid and lipid-protein domains in model membranes. A laser Raman study.

The effect of hexachlorocyclohexane (all isomers) on the thermal transition properties of phospholipid liposomes was determined by Raman spectroscopy. Raman spectra of liposomes with and without the presence of hexachlorocyclohexanes were recorded in the C-H stretching region which shows three major bands around 2850, 2880 and 2930 cm-1. Thermal transition properties were estimated from plots of I2880/I2850 and or I2930/I2850 vs. temperature, where I represents the intensity of the respective band. Our data on phospholipid liposomes reveal that delta- and gamma-hexachlorocyclohexanes drastically reduce and broaden the main thermal transitions of phospholipids at toxic level concentrations. These effects are more pronounced in liposomes containing 18 or more carbon atom long acyl chains. Alpha- and beta-isomers at similar concentrations show a minimum effect on the thermal transition properties of phospholipids. Raman analysis of phospholipid liposomes containing melittin, interestingly, reveal that the delta-isomer unlike the gamma-isomer strongly alters the transition properties of boundary lipids. These data suggest that the effect of hexachlorocyclohexanes on the thermal transition properties of membranes is stereo specific and that the delta-isomer preferably disrupts the lipid-protein domains. Results are explained on the basis of the dynamic flexibility owing to the equatorial and axial chlorine atoms of various hexachlorocyclohexane isomers.

Chemical Phenomena↗
PubMed1990

Early postnatal dexamethasone therapy in premature infants with severe respiratory distress syndrome: a double-blind, controlled study.

To determine whether early (less than or equal to 12 hours) postnatal dexamethasone therapy would facilitate removal of the endotracheal tube and improve outcome in premature infants with severe respiratory distress syndrome, we conducted a double-blind, controlled study of 57 infants whose birth weights were less than 2000 gm. The placebo (n = 29) and treated (n = 28) groups were comparable in birth weight (mean +/- SD: 1273 +/- 323 vs 1318 +/- 359 gm), gestational age (30.1 +/- 2.1 vs 30.8 +/- 2.7 weeks), postnatal age (8.7 +/- 3.1 vs 8.5 +/- 3.1 hours), and pulmonary function at the start of the study. The dose of dexamethasone was 1.0 mg/kg/day for 3 days and then was progressively decreased for 12 days. Infants in the dexamethasone group had significantly higher pulmonary compliance, tidal volume, and minute ventilation, and required lower mean airway pressure for ventilation than infants in the placebo group. The endotracheal tube was successfully removed from more infants in the dexamethasone group (16/28 vs 8/29; p less than 0.025). Nineteen infants (65%) in the placebo group and 11 (39%) in the dexamethasone group (p less than 0.05) had lung injuries. Dexamethasone therapy was associated with a temporary increase in blood pressure and plasma glucose concentration and a delay in somatic growth. We conclude that early postnatal dexamethasone therapy improves pulmonary status, facilitates removal of the endotracheal tube, and minimizes lung injuries in premature infants with severe respiratory distress syndrome.

Clinical Trials as Topic↗
PubMed1990

Role of proteins in protection against radiation-induced damage in membranes.

The effect of gamma irradiation on liposomes in the presence of a large number of commercially available proteins has been studied. Experiments were designed to demonstrate that the configuration of both acyl chain and cis C = C bonds created by lipid-protein associations are crucial in autocatalyzed radiation-induced lipid peroxidation. Raman spectroscopy was used to characterize these states. Raman spectra in the C-C stretching region show three prominent bands at 1064, 1090, and 1125 cm-1, assigned to trans, gauche, and trans C-C bonds, respectively. A single symmetrical C = C stretching band assigned to the cis isomer occurs at 1660 cm-1. The intensity ratios (I1064/I1090) and (I1660/I1440) are used as Raman probes to define the conformational states of acyl chains and C = C bonds, respectively. Our data show that the ratio (I1064/I1090) decreases in the presence of proteins, indicating that these proteins induce more gauche structures. Upon irradiation, the ratio (I1064/I1090) increases by about 30% in the absence of proteins and by about 15% in the presence of proteins. This shows that proteins retain the gauche structures in irradiated samples. The ratio (I1660/I1440) decreases in liposomes containing proteins, showing that proteins modify the configuration of cis C = C bonds. Upon irradiation, this ratio decreases by about 45-50% in samples without proteins and by about 10% in samples with proteins. These data show that proteins inhibit the radiation-induced configurational changes in the cis C = C bonds. The determination of radiation-induced peroxides (as malondialdehyde equivalents) in liposomes reveals that proteins inhibit the formation of peroxide products at low molar ratio and that the preventive capacity of different proteins is different. We conclude that proteins alter the conformation of both acyl chains and cis C = C bonds in liposomes and that these altered states are less sensitive to radiation-induced peroxidation.

Cesium Radioisotopes↗
PubMed1986

Synthesis of some new hydrazone derivatives as biologically active agents.

A series of [4-(6H/bromo-4-oxo-2-phenyl-3(4H)-quinazolinyl)phenoxy]acetic acid (1,2-dihydro-1-H/methyl-2-oxo-3H-indol-3-ylidene)hydrazides (VII1-16) were synthesised by condensing 1-H/methyl-5-substituted indoline-2,3-diones with [4-(6H/bromo-4-oxo-2-phenyl-3(4H)-quinazolinyl) phenoxy]acetic acid hydrazides (IV1-2) which in turn were obtained by reacting ethyl [4-(6H/bromo-4-oxo-2-phenyl-3(4H)-quinazolinyl)phenoxy]acetates (III1-2) with hydrazine hydrate. All the synthesised compounds (VIII1-16) were screened for their antibacterial, acetylcholinesterase enzyme inhibitory and antiviral activities.

Antiviral Agents↗
PubMedDate not supplied

Does B.C.G. vaccination prevent or postpone the occurrence of tuberculous meningitis?

The reported efficiency of B.C.G. vaccine in prevention of primary childhood or sputum positive adult tuberculosis vary widely but it is believed to offer significant protection against hematogenous forms of tuberculosis. The present hospital-based, case control study was aimed at evaluation of impact of B.C.G. vaccination on one of the hematogenous forms of tuberculosis i.e. Tuberculous meningitis (TBM). Records of cases of TBM admitted in the pediatric wards of Lok Nayak Hospital, Delhi, over one year were analyzed retrospectively for B.C.G. positivity status and age distribution. The results were compared with similar data obtained from a control group comprising of non-TBM cases in pediatric wards of same hospital, recruited on 2 days, separated by an interval of three weeks. No statistically significant difference was found in B.C.G. positivity status of cases and control groups. However, there was an obvious trend in age distribution among cases of TBM with respect to the B.C.G. status, with a significantly higher proportion of B.C.G. vaccinated children in over 5-year age group, as compared to those in under 5 year age group. The results, therefore, indicate probable effectiveness of B.C.G. against TBM only for a limited duration i.e. single B.C.G. immunization only postpones rather than prevent the occurrence of TBM.

Adult↗
PubMedDate not supplied

Effect of dexamethasone therapy on the neonatal ductus arteriosus.

Patent ductus arteriosus (PDA) is believed to be a contributing factor in the etiopathogenesis of bronchopulmonary dysplasia (BPD). We studied the effects of early dexamethasone therapy on persistent ductal patency and the role of PDA in the etiopathogenesis of BPD during the course of a randomized double-blind trial of dexamethasone to prevent BPD. Infants, who weighed between 700 and 999 g, had severe RDS, and had been given surfactant, were randomized to receive a 12-day course of dexamethasone (n = 13) or placebo (n = 17) starting within the first 12 hours of postnatal life. The diagnosis of PDA was made clinically and was confirmed by cardiac ultrasound. The incidence of clinically significant ductus in infants who weighed less than 1000 g was 23% in the dexamethasone-treated group, as compared with 59% in infants who were given placebo. This difference was marginally significant, p = 0.05, odds ratio 0.21, 95% confidence interval 0.04-1.05. None of the infants in the dexamethasone group had recurrence of PDA after indomethacin therapy as compared with three infants in the placebo group. Dexamethasone significantly reduced the number of days infants required ventilator and supplemental oxygen as compared with infants who received placebo. Dexamethasone, as compared with placebo, also reduced the incidence of BPD, p = 0.025, odds ratio 0.08, 95% confidence interval 0.01-0.58. Dexamethasone may reduce the incidence of PDA in premature infants who weigh less than 1000 g at birth and thereby reduce the incidence of BPD.

Anti-Inflammatory Agents↗
PubMedDate not supplied

Lower accuracy of TI-201 SPECT in women is not improved by size-based normal databases or Wiener filtering.

BACKGROUND: We have shown that the diagnostic accuracy of quantitative single photon emission computed tomography (SPECT) thallium 201 myocardial perfusion imaging is lower in women than in men and that much of the difference can be explained by the smaller size of the left ventricle in women. Therefore attempts at improving the accuracy of myocardial perfusion imaging in women should focus on the problem of lower accuracy in patients with small chamber size. We evaluated two strategies for this: size- and gender-based normal databases and inverse filtering with the Wiener filter. METHODS AND RESULTS: We identified 618 patients undergoing exercise SPECT TI-201 who either had a low pre-test probability of coronary artery disease or had catheterization-documented disease. Their images were analyzed on the basis of gender and chamber size: both gender and size- and gender-based normal databases were created. The studies were analyzed quantitatively, and the accuracy was evaluated by use of the area under the receiver operating characteristic (ROC) curve. Chamber size was significantly lower in women (size index 69+/-22 women vs 96+/-28 men; P < .0001). The accuracy of myocardial perfusion imaging was lower in women compared with men (ROC area: 0.92+/-0.01 men vs 0.85+/-0.03 women; P = .03), and there was an even greater difference in accuracy between patients with large versus small chamber size (ROC area: 0.94+/-0.01 large vs 0.81+/-0.03 small; P < .001). There was no improvement in the diagnostic accuracy either in women or in patients with small chamber size when a size- and gender-based normal database, Wiener filter, or the Wiener filter with a size- and gender-based normal database was used. CONCLUSION: The left ventricular chamber size in women is smaller than that in men. There is a significant difference in the accuracy of quantitative SPECT TI-201 between men and women and an even greater difference between patients with large versus small chamber size. Neither size- and gender-based databases nor Wiener filtering significantly improves accuracy in women or in patients with small chamber size.

Aged↗
PubMedDate not supplied

Aetiology of chronic diarrhoea in tropical children.

AIM: We studied the causes and presentations of chronic diarrhoea in post-weaned children. METHODS: Forty seven children (6 months to 12 years) with diarrhoea of more than 2 weeks duration were recruited and subjected to detailed clinical examination and investigations. RESULTS: Primarily on the basis of history, clinical examination and duodenal biopsy, children could be classified into 5 groups namely tropical enteropathy (46.8%), irritable bowel syndrome (10.6%), giardiasis (14.8%), celiac disease (6.8%) and non specific diarrhoea (21.8%). Children with tropical enteropathy improved with broad spectrum antimicrobial therapy, those with irritable bowel syndrome and non specific chronic diarrhoea with dietary interventions while children with celiac disease required definite withdrawal of gluten from diet.

Celiac Disease↗