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Biomedical subjects

R Aggarwal

Publications and source records attributed to R Aggarwal.

At least 73 records · Page 4Linked to original sources
PubMed2000

Interrelationship between angiographically defined coronary artery disease, plasma insulin levels and lipids in Indian patients.

We investigated the interrelationship between plasma insulin levels, various lipoproteins and coronary artery disease. No significant differences were observed on comparing patients with controls for plasma insulin, high density lipoprotein cholesterol, fasting blood sugar levels and triglyceride levels. However patients showed significantly higher levels of total cholesterol and low density lipoprotein cholesterol compared with controls. No significant differences were observed on comparing patients of multivessel disease with single vessel disease in serum insulin or various lipid subfractions. In addition, there was no correlation between serum insulin quartiles and various biochemical parameters. In conclusion, in this cross-sectional study plasma insulin levels failed to show any significant association with severity and extent of coronary artery disease. Further there was no correlation of various lipid parameters with insulin quartiles.

Adult↗
PubMed1999

Cellular mechanisms of altered contractility in the hypertrophied heart: big hearts, big sparks.

To investigate the cellular mechanisms for altered Ca2+ homeostasis and contractility in cardiac hypertrophy, we measured whole-cell L-type Ca2+ currents (ICa,L), whole-cell Ca2+ transients ([Ca2+]i), and Ca2+ sparks in ventricular cells from 6-month-old spontaneously hypertensive rats (SHRs) and from age- and sex-matched Wistar-Kyoto and Sprague-Dawley control rats. By echocardiography, SHR hearts had cardiac hypertrophy and enhanced contractility (increased fractional shortening) and no signs of heart failure. SHR cells had a voltage-dependent increase in peak [Ca2+]i amplitude (at 0 mV, 1330+/-62 nmol/L [SHRs] versus 836+/-48 nmol/L [controls], P<0.05) that was not associated with changes in ICa,L density or kinetics, resting [Ca2+]i, or Ca2+ content of the sarcoplasmic reticulum (SR). SHR cells had increased time of relaxation. Ca2+ sparks from SHR cells had larger average amplitudes (173+/-192 nmol/L [SHRs] versus 109+/-64 nmol/L [control]; P<0.05), which was due to redistribution of Ca2+ sparks to a larger amplitude population. This change in Ca2+ spark amplitude distribution was not associated with any change in the density of ryanodine receptors, calsequestrin, junctin, triadin 1, Ca2+-ATPase, or phospholamban. Therefore, SHRs with cardiac hypertrophy have increased contractility, [Ca2+]i amplitude, time to relaxation, and average Ca2+ spark amplitude ("big sparks"). Importantly, big sparks occurred without alteration in the trigger for SR Ca2+ release (ICa,L), SR Ca2+ content, or the expression of several SR Ca2+-cycling proteins. Thus, cardiac hypertrophy in SHRs is linked with an alteration in the coupling of Ca2+ entry through L-type Ca2+ channels and the release of Ca2+ from the SR, leading to big sparks and enhanced contractility. Alterations in the microdomain between L-type Ca2+ channels and SR Ca2+ release channels may underlie the changes in Ca2+ homeostasis observed in cardiac hypertrophy. Modulation of SR Ca2+ release may provide a new therapeutic strategy for cardiac hypertrophy and for its progression to heart failure and sudden death.

Animals↗
PubMed1999

Radial artery in CABG: could the early results be comparable to internal mammary artery graft?

BACKGROUND: The accidental detection of patency of radial artery grafts, by Acar, which had been labeled as blocked 18 years earlier, has led to its revival as a conduit in coronary artery bypass surgery. We used radial artery as one of the grafts in 287 patients from February 1996 to June 1998. Here we present our early clinical experience and the midterm angiographic follow up of the initial 62 patients. METHODS: A no touch, atraumatic harvesting technique coupled with gentle hydrostatic and pharmacological dilatation of the radial artery graft was employed. Radial artery was used to revascularize coronary vessels with >80% proximal stenosis. Postoperatively, the patients were administered a low dose nifedipine that was continued for 6 months thereafter. The patients were followed up clinically after discharge from the hospital and angiographic evaluation of the grafted radial artery by selective injection was done at a mean interval of 16.2 +/- 5.1 months (3-24 months) postoperatively. RESULTS: There was no perioperative or late myocardial infarction or mortality. No significant complications related to the harvesting of radial artery were encountered. Angiographically, the radial artery grafts were found to be patent in 96.8% of patients (60/62). Mild distal anastomotic narrowing was seen in angiogram of one patient with good filling of the target vessel. Another patient showed diffuse spasm of radial artery graft. The patency of the pedicled left internal mammary grafts was also 98.2% (56/57). All the patients were asymptomatic. CONCLUSIONS: Radial artery seems to be an excellent alternate arterial conduit for myocardial revascularization with early and midterm patency rates equivalent to that of pedicled internal mammary artery, and it should be used more often for myocardial revascularization as an adjunct to pedicled internal mammary artery graft.

Adult↗
PubMed1999

Genetic variability of hepatitis E virus within and between three epidemics in India.

Hepatitis E virus (HEV) is an important cause of epidemic and sporadic acute viral hepatitis in many developing countries, including India. We evaluated the genetic variability within two regions (a 476-nt long ORF1 segment and a 304-nt long ORF2 segment) from specimens collected during three outbreaks in the cities of Karnal (1987), Yamunanagar (1989), and Meerut (1996), India, and from one patient, residing in Lucknow, India, who had a case of sporadic hepatitis (1996). Within an outbreak, sequences in the ORF1 and ORF2 regions were 99.3-100.0% identical. However, when strains were compared between outbreaks, identity in the ORF1 and ORF2 region was 97.1-99.2 and 96.4-100.0%, respectively. A comparison of these sequences to previously published Indian ORF1 and ORF2 sequences revealed even lower similarities, 95.2-98.5 and 95.1-98.7%, respectively. One patient in the Meerut outbreak had genomic sequences that differed substantially from the other patients affected during this outbreak and probably reflected a sporadic infection. The sporadic hepatitis E strain from Lucknow clustered with a previously described HEV strain from a patient with fulminant hepatic failure (FHF). Our data suggest that the ORF1 and ORF2 segments can be used to study the molecular epidemiology of HEV infection and indicate that much remains to be determined about the genetic variability of Indian HEV strains.

Base Sequence↗
PubMed1999

Genetic variation affecting heart rate in Drosophila melanogaster.

Heart rate in pre-pupae of Drosophila melanogaster is shown to vary over a wide range from 2.5 to 3.7 beats per second. Quantitative genetic analysis of a sample of 11 highly inbred lines indicates that approaching one-quarter of the total variance in natural populations can be attributed to genetic differences between flies. A hypomorphic allele of the potassium channel gene ether-a-gogo, which is homologous to a human long-QT syndrome susceptibility gene (HERG), has a heart rate at the low end of the wild-type range, but this effect can be suppressed in certain wild-type genetic backgrounds. This study provides a baseline for investigation of pharmacological and other physiological influences on heart rate in the model organism, and implies that quantitative genetic dissection will provide insight into the molecular basis for variation in normal and arrhythmic heart function.

Animals↗
PubMed1999

Diagnostic and therapeutic approaches to carotid body tumours: report of three cases and review of the literature.

BACKGROUND: Carotid body tumour is a rare neoplasm of the carotid body. Three cases of carotid body tumour presenting as a painless progressive mass in the neck region are reported here. A review of the relevant literature regarding carotid body tumours is also presented. METHODS: Angiographic features were diagnostic of carotid body tumour and complete surgical excision was done. RESULTS: There was no mortality and minimum morbidity. There were no malignant tumours. All three patients belong to the high-altitude area of Himachal Pradesh. CONCLUSIONS: A high degree of clinical suspicion of upper posterior triangle neck masses and an accurate diagnostic work-up are needed for operative planning.

Adult↗
PubMed1998

Hepatitis E virus RNA detection in serum and feces specimens with the use of microspin columns.

This report describes the use of microspin columns for extraction of hepatitis E virus (HEV) RNA from stool and serum specimens for reverse transcription-polymerase chain reaction (RT-PCR) and compares this method with the glass powder method. The microspin column method was found to be 1- to 2-log more sensitive in detecting HEV RNA than the glass powder method and had better reproducibility. The microspin column method also detected HEV RNA in a larger number of specimens than the glass powder method from among a panel of serum and stool specimens. Use of this method may allow better assessment of viremia and fecal excretion in patients and experimental animals infected with HEV.

Animals↗
PubMed1998

Oesophageal motility and gastro-oesophageal reflux: effect of variceal eradication by endoscopic sclerotherapy.

Endoscopic injection sclerotherapy (EIS) is known to produce oesophageal structural and motility changes; however, alterations in frequency and severity of gastro-oesophageal reflux (GER) following EIS have not been investigated in detail. We studied 22 patients with cirrhosis and oesophageal varices before EIS and 26 after variceal eradication with intravariceal EIS using manometry and 24 h pH monitoring. The post-EIS group had reduced oesophageal sphincter pressure (19.2+/-11.4 vs 26.1 +/-16.4 mmHg, P< 0.05) and slower velocity of oesophageal peristalsis (2.47+/-0.71 vs 3.06+/-0.77 cm/s, P< 0.01) than the pre-EIS patients. There was no difference in the amplitude or duration of the contraction. Abnormal contraction wave-forms were observed more frequently in post-EIS than in the pre-EIS patients (3/22 vs 12/26, P< 0.05). Various quantitative parameters for GER were not increased in post-EIS compared with pre-EIS patients. Abnormal GER was present in nine of 21 pre-EIS and eight of 17 post-EIS patients (no significant difference). These results suggest that although persistent oesophageal motility changes are frequent after intravariceal EIS, these do not lead to a significant increase in GER.

Adult↗
PubMed1998

Significance of elevated IgG anticardiolipin antibody levels in patients with Budd-Chiari syndrome.

OBJECTIVES: Budd-Chiari syndrome (BCS) is characterized by hepatic venous outflow obstruction. Though hypercoagulable states are implicated in the causation of BCS, the etiology remains unknown in most cases. Presence of anticardiolipin antibodies (aCL) is a known cause of hypercoagulable state. We therefore studied the frequency of IgG aCL in BCS. METHODS: Sera were obtained from 19 patients with BCS, 50 healthy controls, 18 age- and gender-matched patients with cirrhosis, and 15 patients with acute viral hepatitis. IgG aCL levels were measured using a solid-phase enzyme immunoassay. Values exceeding mean + 2 SD of healthy controls were taken as abnormal. RESULTS: Mean +/- SD IgG aCL levels (GPL units) in the four groups were: healthy controls, 6.3 +/- 4.4; BCS, 13.8 +/- 13.3 (p < 0.05, compared with healthy controls); cirrhosis, 15.1 +/- 14.9 (p < 0.05, compared with healthy controls and p = ns, compared with BCS patients); and acute viral hepatitis, 5.0 +/- 2.5 (p = ns, compared with healthy controls). The levels in BCS and cirrhosis patients were similar (p = ns). The number of patients with elevated aCL was: healthy controls, 3/50; BCS, 6/19; cirrhosis, 7/18; and acute viral hepatitis, 0/15. The number of patients with elevated IgG aCL was significantly higher among patients with BCS and cirrhosis, compared with controls (p = 0.03 and p = 0.002, respectively). CONCLUSIONS: Patients with BCS had higher IgG aCL levels than healthy controls. However, as aCL levels were also elevated in patients with cirrhosis, the pathogenetic role of IgG aCL in the causation of BCS is doubtful.

Acute Disease↗
PubMed1998

Relationship of manometric findings to symptomatic response after pneumatic dilation in achalasia cardia.

BACKGROUND: Achalasia cardia is usually treated by pneumatic dilation or surgical esophagomyotomy. The role of esophageal manometry for objective assessment of symptom response is controversial. AIM: To study the relationship between symptoms and manometric parameters before and after pneumatic dilation in patients with achalasia cardia. METHODS: Sixteen patients with achalasia cardia underwent esophageal manometry before and after undergoing pneumatic dilation. At each time, lower esophageal sphincter (LES) pressure and mean basal esophageal-gastric pressure gradient (MIEP-MIGP) were measured. RESULTS: Good symptom response was obtained in 12 of 16 patients. Median (range) LES pressure fell from 42 (17-51) mmHg to 18 (8-39) mmHg in those patients with a good response, and from 51 (25-68) mmHg to 29.5 (23-42) mmHg in those who responded poorly. Mean intraesophageal pressure fell below mean intragastric pressure in both the groups. CONCLUSIONS: Esophageal manometry does not correlate with symptom improvement after pneumatic dilation in achalasia cardia. Dysphagia may persist in spite of reversal of the MIEP-MIGP gradient.

Adolescent↗
PubMed1997

Tetrodotoxin-blockable calcium currents in rat ventricular myocytes; a third type of cardiac cell sodium current.

1. Whole-cell patch clamp currents from freshly isolated adult rat ventricular cells, recorded in external Ca2+ (Ca2+o) but no external Na+ (Na+o), displayed two inward current components: a smaller component that activated over more negative potentials and a larger component (L-type Ca2+ current) that activated at more positive potentials. The smaller component was not generated by Ca2+ channels. It was insensitive to 50 microM Ni2+ and 10 microM La3+ but suppressed by 10 microM tetrodotoxin (TTX). We refer to this component as ICa(TTX). 2. The conductance-voltage, g(V), relation in Ca2+o only was well described by a single Boltzmann function (half-maximum potential, V1/2, of -44.5; slope factor, k, of -4.49 mV, means of 3 cells). g(V) in Ca2+o plus Na+o was better described as the sum of two Boltzmann functions, one nearly identical to that in Ca2+o only (mean V1/2 of -45.1 and k of -3.90 mV), and one clearly distinct (mean V1/2 of -35.6 and k of -2.31 mV). Mean maximum conductance for ICa(TTX) channels increased 23.7% on adding 1 mM Na+o to 3 mM Ca2+o. ICa(TTX) channels are permeable to Na+ ions, insensitive to Ni2+ and La3+ and blocked by TTX. They are Na+ channels. 3. ICa(TTX) channels are distinct from classical cardiac Na+ channels. They activate and inactivate over a more negative range of potentials and have a slower time constant of inactivation than the classical Na+ channels. They are also distinct from yet another rat ventricular Na+ current component characterized by a much higher TTX sensitivity and by a persistent, non-fast-inactivating fraction. That ICa(TTX) channels activate over a more negative range of potentials than classical cardiac Na+ channels suggests that they may be critical for triggering the ventricular action potential and so of importance for cardiac arrhythmias.

Animals↗
PubMed1997

Frequency dependent effects on Cai transients and cell shortening in myocytes that survive in the infarcted heart.

UNLABELLED: Myocytes that survive in the epicardial border zone of the healing canine infarcted heart provide the substrate for inducible reentrant ventricular arrhythmias. These myocytes have been shown to have altered Ca2+ currents which could impact on Cai homeostasis in these cells. OBJECTIVE AND METHODS: To directly measure and compare intracellular Ca2+ transients and cell shortening in myocytes dispersed from control noninfarcted hearts with those from epicardial border zone of 5 day infarcted canine hearts using the Ca2+ sensitive indicator fura-2/AM. Studies were designed to determine and compare the effects of rate and premature stimulation on intracellular Ca2+ in the two cell types. RESULTS: Epicardial cells from noninfarcted hearts (1) exhibited an increase in amplitude of the fura-2 ratio with decreasing pacing cycle length (CL), while cells from the infarcted heart showed the opposite effect; (2) showed more marked acceleration of relaxation of the Cai transient with decreasing CL than myocytes from the infarcted heart; (3) exhibited little or no post rest potentiation in contrast to cells from the infarcted heart; and (4) showed a more rapid recovery during restitution protocols than cells from the infarcted heart. Cell shortening differences were also observed between cell populations in that most cells from the infarcted zone did not show any degree of cell shortening despite the reasonable intracellular Ca2+ transient. CONCLUSIONS: The handling of intracellular Ca2+ in myocytes that have survived in the epicardial border zone is very different from that of normal epicardial myocytes suggesting that there may exist marked heterogeneity in intracellular Ca2+ handling in cells in the in situ healing infarcted heart. Electrophysiologic implications of these findings are discussed.

Animals↗
PubMed1997

Sexually-transmitted disease (STD) markers in multitransfused children in relation to human immunodeficiency virus type-1 (HIV-1) infection: impact of STD markers in blood donors.

Association of serological markers for various sexually transmitted diseases (STDs) with Human Immunodeficiency Virus type 1 (HIV-1) infection among heterosexually promiscuous blood donors is well recognized. However, possibility of similar association among children receiving transfusion from these donors has not been adequately explored. Study on the association of some STD markers with HIV-1 infection in multitransfused (MT) children showed that both HIV-1 positive and HIV-1 negative groups of children had significantly higher prevalence of hepatitis B virus (HBV) markers, i.e. HBsAg (23 and 30 per cent), anti-HBs (46 and 57 per cent), anti-HBc (18 and 23 per cent), antibodies to cytomegalovirus of IgM class (36 and 37 per cent) and IgG class (72.7 and 70 per cent), IgG antibodies to Herpes Simplex Virus type-2 (23 and 23 per cent) compared to control group. However, seropositivity for HIV-1 infection could not be attributed as a risk factor for any of these markers in the group of MT children. On the contrary, significant association of anti HBc, anti HCV, CMV IgG and antitreponemal antibody with HIV-1 infection could be recorded in the group of blood donors. It appeared that due to low prevalence of HIV-1 infection among blood donors in India, both HIV-1 positive and HIV-1 negative groups of MT children received transfusion from HIV negative donors predominantly resulting in a comparable prevalence of STD markers in both the groups of MT children due to cumulative effect of transfusion from HIV-1 negative donors.

Biomarkers↗