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Biomedical subjects

V Chopra

Publications and source records attributed to V Chopra.

At least 19 recordsLinked to original sources
PubMed2006

Alterations in the virulence potential of enteric pathogens and bacterial-host cell interactions under simulated microgravity conditions.

Host immune mechanisms were proposed to decline under microgravity conditions during spaceflights, which might result in severe infections in astronauts. Therefore, it was important to investigate the effects of microgravity on infecting organisms and their interaction with host cells. Data showed that simulated microgravity (SMG) conditions markedly increased production of the enterotoxigenic Escherichia coli (ETEC) heat-labile enterotoxin, which induced fluid secretory responses in a mouse model. SMG also enhanced production of tumor necrosis factor-alpha in murine macrophages infected with enteropathogenic E. coli (EPEC). In a similar fashion, simulated microgravity conditions augmented the invasive potential of Salmonella enterica serovar typhimurium and enhanced production of tumor necrosis-factor alpha in S. typhimurium-infected epithelial cells. Furthermore, coculturing of macrophages and S. typhimurium in a simulated microgravity environment resulted in activation of stress-associated mitogen-activated protein kinase kinase 4. Using the antiorthostatic tail suspension mouse model, which simulates some aspects of microgravity, oral inoculation of S. typhimurium markedly reduced the 50% lethal dose compared to mice infected under normal gravitational conditions. Microarray analysis revealed simulated microgravity-induced alterations in the expression of 22 genes in S. typhimurium, and protein expression profiles were altered in both EPEC and S. typhimurium, based on two-dimensional gel electrophoresis. These studies indicated alterations in the virulence potential of bacteria and in host responses to these pathogens under simulated microgravity conditions, which may represent an important environmental signal. Such studies are essential for better understanding bacterial-host cell interactions, particularly in the context of spaceflights and space habitations of long duration.

Animals↗
PubMed2004

Lipoprotein(a) as a marker of coronary artery disease and its association with dietary fat.

OBJECTIVE: The main objectives of the study were to evaluate the effect of dietary fat on plasma lipoprotein(a) [Lp(a)] levels and to study the potential of Lp(a) as a more reliable marker for CAD compared to other lipids and lipoproteins. METHODS: Twenty CAD patients and 20 healthy controls were recruited for the study. Their fasting plasma Lp(a) levels and complete lipid profile were assayed. The fat intake was calculated using 24 hours dietary recall method. The patients and controls were each divided into two subgroups: Group A consuming dietary fat > 30% and Group B consuming dietary fat < or = 30% of the total kilo-calories/day. RESULTS: Results indicated that plasma Lp(a), total serum cholesterol (TC), tryglyceride (TG), low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C) and LDL-C/HDL-C ratio of CAD patients were significantly higher than the controls. High fat intake was found to be associated with higher plasma Lp(a) levels (p<0.05) in patients only. No significant correlation was found between Lp(a) levels and other conventional lipoproteins. CONCLUSION: The lack of correlation between Lp(a) and other lipoproteins indicates its potential as an independent risk factor for CAD. High fat intake led to higher plasma Lp(a) levels in patients; hence it would be worthwhile to evaluate the effect of quality and quantity of fat intake on plasma Lp(a) levels in a larger sample size.

Adult↗
PubMed2001

Effects of 5-aminolaevulinic acid on human ovarian cancer cells and human vascular endothelial cells in vitro.

Results are reported on the cellular effects and the sensitivity of cultured tumor epithelial cells (TEC) derived from human ovarian cystadenocarcinoma and human umbilical vein-derived endothelial cells (HUVEC) to exogenous 5-aminolaevulinic acid (ALA) and ALA-induced photodynamic therapy (PDT). Cellular alterations and PDT efficiency were evaluated using colorimetric thiazolyl blue (MTT) assay, trypan blue exclusion assay, electron microscopy, and gel electrophoresis. ALA-induced protoporphyrin IX (PpIX) accumulation in TEC was associated with a concentration and time-dependent significant decrease in mitochondrial activity, increase in cell membrane permeability, and dark toxicity. Maximum PpIX loaded TEC demonstrated a high sensitivity to PDT. Neither cellular alterations nor PDT effects were observed in HUVEC under identical experimental conditions. These results indicate a potential clinical value for the use of ALA-mediated PDT to treat minimal residual disease in mucinous ovarian carcinoma. In addition, the ALA-induced PpIX cytotoxicity may be exported to a new chemotherapeutic regimen via a conventionally viewed photochemotherapeutic agent.

Aminolevulinic Acid↗
PubMed2001

HIP1 functions in clathrin-mediated endocytosis through binding to clathrin and adaptor protein 2.

Polyglutamine expansion in huntingtin is the underlying mutation leading to neurodegeneration in Huntington disease. This mutation influences the interaction of huntingtin with different proteins, including huntingtin-interacting protein 1 (HIP1), in which affinity to bind to mutant huntingtin is profoundly reduced. Here we demonstrate that HIP1 colocalizes with markers of clathrin-mediated endocytosis in neuronal cells and is highly enriched on clathrin-coated vesicles (CCVs) purified from brain homogenates. HIP1 binds to the clathrin adaptor protein 2 (AP2) and the terminal domain of the clathrin heavy chain, predominantly through a small fragment encompassing amino acids 276-335. This region, which contains consensus clathrin- and AP2-binding sites, functions in conjunction with the coiled-coil domain to target HIP1 to CCVs. Expression of various HIP1 fragments leads to a potent block of clathrin-mediated endocytosis. Our findings demonstrate that HIP1 is a novel component of the endocytic machinery.

Adaptor Protein Complex 2↗
PubMed2000

Isolated congenital coronary arteriovenous fistula.

During the last eight years a total of nine cases of isolated congenital coronary arteriovenous fistula (CAVF) have been diagnosed at our centre. Age of these patients ranged from 11 days to 22 years (mean 6.4 +/- 4.2 years). There were seven male and two female patients. Right and left coronary arteries were the sites of origin in seven and three cases respectively. One patient had two fistulae, one each originating from right coronary artery and obtuse marginal artery. The drainage sites were right ventricle in seven cases and right atrium in two. The pulmonary artery pressure was normal in eight cases and elevated in one case. The pulmonary artery to systemic flow ratio ranged from 1.1:1-2.4:1 in all except the 11 day-old-baby in whom it was 4:1. Pulmonary vascular resistance (PVRI) was below 3.5 in all cases (range 1.0-3.5 units). Surgical ligation of fistula was done in four cases and two patients underwent coil embolisation of fistula. Follow-up is available in five out of eight patients including three cases in whom CAVF was closed. Two other young patients are being followed-up conservatively and all the patients are asymptomatic. CAVF can present at any age; majority of the cases have small left to right shunts and more commonly CAVF arise from right coronary artery. Surgical ligation of fistula is safe in older patients, non-surgical embolisation using coils may be an alternative to surgery in selected cases.

Adolescent↗
PubMed2000

I-cell disease (Mucolipidosis II).

I-cell disease (Mucolipidosis II) is one of the lysosomal storage diseases which presents in the neonatal period, and within six months will phenotypically resemble the severe forms of the group of disorders called the "mucopolysaccharidoses" but without mucopolysacchariduria. In Mucolipidosis II, fibrocytes exhibit "abnormal lysosomes". Activities of several lysosomal enzymes are low in fibroblast cultures but high in mucolipidosis II serum. We present a patient with I-cell disease diagnosed on the basis of clinical, radiological and biochemical features. The mother of this child was pregnant and the fetus was also found to be affected.

Child, Preschool↗
PubMed2000

Serum levels of lipoprotein (a) and other lipids in angiographically defined coronary artery disease patients and healthy blood bank donors.

Lipoprotein (a) (Lp(a)) and other lipid values have been correlated with angiographically defined [table: see text] coronary artery disease. To study this relationship in Indian patients, plasma levels of Lipoprotein (a) and other lipids were assessed in 74 patients undergoing Coronary arteriography and also in 53 age and sex matched healthy male blood bank donors who served as controls. Total cholesterol (mg/dl) (211 +/- 56 vs 186 +/- 43; p < 0.001), low density lipoprotein Cholesterol (mg/dl) (117 +/- 40 vs 88 +/- 29; p > 0.001) and low density lipoprotein/high density lipoprotein cholesterol ratio (2.6 +/- 0.8 vs 2.2 +/- 0.9; p < .001) were significantly higher in patients than controls. High density lipoprotein-cholesterol (mg/dl) (43.5 +/- 6 vs 42.1 +/- 7; p-ns) very low density lipoprotein-cholesterol (mg/dl) (49.7 +/- 17 vs 56.1 +/- 25; p-ns) and triglycerides (mg/dl) (155 +/- 101 vs 167 +/- 88; p-ns) were not statistically different in two groups. Lipoprotein (a) levels showed highly skewed distribution. Patients (n = 74) showed almost five fold higher lipoprotein (a) levels (mg/dl) as compared to controls (n = 53) [105 +/- 565 vs 23 +/- 76]. Patients with very high lipoprotein (a) levels [values of more than 40 mg/dl] (n = 18) had high density lipoprotein cholesterol and total cholesterol significantly lower than rest of the patient group. [high density lipoprotein cholesterol (mg/dl) 41.00 +/- 3.7 vs 44 +/- 6.4; p < 0.01 and total cholesterol (mg/dl) 192 +/- 34 vs 217 +/- 53; p < 0.05].

Adult↗
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

Oncogene expression and microvessel count in recurrent and nonrecurrent stage Ib squamous cell carcinoma of the cervix.

OBJECTIVE: To evaluate p53, epidermal growth factor receptor (EGFR) and c-erbB-2 oncogene expression and compare it with microvessel count (MVC) in determining the clinical outcome of stage Ib squamous cell carcinoma (SCC) of the cervix. STUDY DESIGN: Immunostaining with p53, EGFR, C-erbB-2 and factor VIII antibodies was performed on tumor sections from 22 patients (11 with cancer recurrence, 11 free of cancer after four years). The levels of oncogene expression were semiquantitatively graded (0-4). Microvessels were counted (per 200 x field) in areas of highest neovascularization. RESULTS: Eight of 11 patients (72.7%) with recurrence expressed EGFR as compared with 5 of 11 patients (45.5%) free of disease. This difference is not significant (P = .39). An equal number of patients with and without recurrence expressed c-erbB-2. Five of 11 patients (45.5%) with recurrence expressed p53, as compared with 6 of 11 (54.5%) free of disease (P = 1.00). Eight of 11 patients (72.7%) with recurrence had an MVC above 24 as compared with 2 of 11 patients (18.2%) free of disease; this difference was statistically significant (P = .03). CONCLUSION: The expression of EGFR, p53 and c-erbB-2 appears to have little prognostic value in stage Ib SCC of the uterine cervix. The prognostic value of MVC is in keeping with previous findings.

Adult↗
PubMed1998

Circulating serum levels of cytokines and angiogenic factors in patients with cervical cancer.

Progression of cervical cancer is associated with excessive circulating levels of cytokines, which are known to be modulators of tumor angiogenesis. The concentrations of cytokines and growth factors were assayed using enzyme-linked immunosorbant assays in the serum of 61 women in various stages of cancer [stage 0 (n = 6), stage I (n = 15), stage II (n = 15), stage III (n = 15), and stage IV (n = 10)] and of 20 healthy control subjects. Our results indicated that b-FGF and TNF-beta levels were significantly elevated in stage I, and serum levels of TGF-beta and IL-7 were elevated in stages II-IV of invasive carcinoma. Our experimental subjects had significantly increased serum levels of IL-6, GM-CSF, and angiogenin in stages I-IV of cervical cancer, and TNF-alpha serum levels were elevated in all stages of invasive carcinoma. The serum levels of IL-8 and IL-10 were elevated only in stages II-III, and the levels of IL-2 were elevated in stages III-IV. The serum levels of IL-1 alpha and IL-1 beta remained unaltered in all stages of cancer progression. Progression of cervical cancer is associated with increased serum levels of angiogenin, IL-2, IL-6, IL-7, IL-8, IL-10, b-FGF TNF-alpha, TGF-beta, TNF-beta, and GM-CSF during different stages, all of which have the potential to be angiogenic amplifiers.

Adult↗
PubMed1997

Serum levels of interleukins, growth factors and angiogenin in patients with endometrial cancer.

The purpose of this work was to study changes in serum levels of interleukins, growth factors and angiogenin during different stages of endometrial cancer progression. Serum levels were assayed by enzyme-linked immunosorbant assay in 59 women with stages I-IV of endometrial cancer (study subjects: stage I, n = 20; stage II, n = 8; stage III, n = 5; stage IV, n = 6) and compared to the serum levels in 20 women without cancer as control subjects. Patients with endometrial cancer had varied serum levels of interleukins and growth factors. There was a significant increase in serum levels of angiogenin in all stages of tumor progression. Levels of interleukin-8 (IL-8), IL-10 and transforming growth factor beta (TGF beta) were significantly elevated in patients with stages I and II carcinoma. The serum levels of tumor necrosis factor alpha (TNF alpha), granulocyte/macrophage-colony-stimulating factor, basic fibroblast growth factor (BFGF), IL-7 and IL-2 were significantly elevated in patients with stages II and III carcinoma and the serum level of tumor necrosis factor beta (TNF beta) was slightly elevated in patients with stage II carcinoma only. The serum levels of IL-1 alpha, IL-1 beta and IL-6 were not elevated in endometrial cancer patients in any of the clinical stages. The results showed that progression of endometrial cancer is associated with increased serum levels of cytokines, growth factors and angiogenin, which possibly amplify angiogenesis during different clinical stages.

Adult↗
PubMed1997

Three-dimensional endothelial-tumor epithelial cell interactions in human cervical cancers.

The purpose of this study is to understand the multicellular interaction between tumor epithelial (TEC) and human umbilical vein endothelial cells (HUVEC). The development of in vitro systems in which to coculture these cells as multicellular aggregates is very critical. Cell lines were established from cervical tumor cells (n = 6) and two from HUVEC (n = 2) and they were cultured as three-dimensional (3-D) multicellular-cultures using Cytodex-3 microcarrier beads in the rotating wall vessel (RWV). After a 240-h incubation, TEC and HUVEC proliferated exponentially to 4.2 x 10(7) and 2.2 x 10(7) cells/ml, respectively, without requiring a feeder layer; in contrast to the two-dimensional (2-D) cultures that average about 8 x 10(5) cells/ml. Phase contrast microscopy indicated formation of 3-D aggregates that varied in size from 0.5 to 5 mm. The size of the aggregates (1-5 mm, 6-14 microcarriers) increased over time; however, the number of aggregates (0.5-1 mm, 2-5 microcarriers) decreased over a long-term incubation (240 h) because the cells merged to form large clumps. Maximum aggregation was observed with TEC at 120 h and HUVEC at 96 h. The culture of TEC in the absence of HUVEC produced minimal differentiation in contrast to cocultures. The TEC and HUVEC as cocultures in RWV proliferated at an accelerated rate (1.3 x 10(7) cells/ml, 96 h). The TEC-HUVEC coculture presented tubular structures penetrating the tumor cell masses, forming aggregates larger in size than the monocultures and typically with greater cell mass and number. The cells were viable (trypan blue exclusion) and metabolically active (glucose utilization) until 240 h. These data suggest that RWV provides a new model that allows us to investigate the regulatory factors that govern tumor angiogenesis.

Adenocarcinoma↗