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Biomedical subjects

H Gupta

Publications and source records attributed to H Gupta.

At least 37 records · Page 2Linked to original sources
PubMed1997

Advances in imaging of the acute abdomen.

Over the last 10 years, the most significant advancement in imaging of the acute abdomen has been the development of helical CT imaging. Rapid breath-hold imaging and improved intravascular opacification have enabled radiologists to obtain volumetric data that can be viewed in smaller slice increments. Helical data can also be analyzed utilizing multiplanar and three-dimensional techniques. With its proven ability to diagnose a wide variety of conditions, CT remains the diagnostic modality of choice for imaging the surgical abdomen. There have been considerable improvements in image resolution in US with improvements in transducer technology. Ultrasonography often serves as the first study in evaluating the pediatric or female patient with right lower quadrant or pelvic pain. Computed tomography may be necessary if US is not diagnostic. Despite these technical advances, plain film radiography should be the first imaging study for suspected cases of bowel perforation or obstruction. Magnetic resonance imaging continues to evolve, with improvements in hardware and software design that allow for faster imaging, but current levels of availability in the acute setting preclude its wider use. Whereas further imaging is not necessary for patients presenting with classic signs and symptoms of various acute abdominal diseases, the atypical patient often requires careful diagnostic imaging. Close consultation between the radiologist and surgeon leads to studies appropriately tailored to meet the diagnostic challenge at hand.

Abdomen, Acute↗
PubMed1997

Apoptosis in the retina.

An enormous interest in cell death over the past several years has catapulted apoptosis to the forefront of scientific research. Apoptosis has been found to mediate cell deletion in tissue homeostasis, embryological development and immunologic function. It also occurs in pathological situations including cancer and AIDS, and is implicated in a variety of ocular diseases. This review presents a brief history of apoptosis and the proper evidence needed in order to claim that apoptosis is taking place. A summary and critique of important investigations concerning the genetic and biochemical regulation of apoptosis is presented, as well as a focus on other studies drawing a connection between apoptosis and cell death in physiological and pathological situations.

Animals↗
PubMed1996

Comparison of a corticopelvic transfer index with renal transit times.

The aim of this study was to compare a simple measure obtained visually from serial images, the corticopelvic transfer index (CPI), with renal transit times obtained by deconvolution. The CPI was defined as the time interval between the appearance of the tracer in the renal cortex to its appearance in the renal pelvis. Four groups of subjects as determined by clinical data and renal transit times were investigated retrospectively: 86 normal kidneys, 20 kidneys with renovascular disorder, 17 kidneys with obstructive nephropathy and 26 kidneys with dilated pelves without obstructive nephropathy. There were good correlations only between the CPI and mean parenchymal transit time (MPTT; r = 0.6) and the whole kidney transit time index (WKTTI; r = 0.8). It was concluded that in centres where gamma-camera studies with deconvolution analysis are not possible, the CPI could be a useful parameter in renal radionuclide scintigraphy for suspected renovascular disorders.

Humans↗
PubMed1996

Targeted contrast agents in MR imaging.

The use of target specific MR contrast agents can dramatically improve information obtained by MR imaging. This review outlines the various components of target specific MR contrast agents, including various carriers (e.g., monoclonal antibodies, peptides, proteins, polysaccharides, polymers, liposomes, and cells) as well as magnetic labels (e.g., metal ion chelates, free radicals, and iron oxides) and focusses on some promising clinical applications.

Antibodies, Monoclonal↗
PubMed1995

Experimental gastrointestinal hemorrhage: detection with contrast-enhanced MR imaging and scintigraphy.

PURPOSE: To examine the use of O-methoxy poly(ethylene)glycol-O'-succinyl-N-epsilon-poly(L-lysyl) gadolinium diethylenetriaminepentaacetic acid (MPEG-PL-Gd-DTPA) as a potential magnetic resonance (MR) angiographic contrast agent for the detection of gastrointestinal (GI) bleeding. MATERIALS AND METHODS: MPEG-PL-Gd-DTPA was used for blood pool enhancement, and MPEG-PL-technetium-99m DTPA was used for planar nuclear imaging studies. GI bleeding was tested in rats by controlled injection of contrast material-doped blood through a jejunostomy catheter. MR imaging was performed at 1.5 T. RESULTS: Ideal flip angle, used with a spoiled gradient-echo pulse sequence, was 40 degrees. The smallest amount of hemorrhage detected at MR imaging was 0.05 mL; at nuclear imaging it was 0.02 mL. With the superior spatial resolution of MR imaging, individual loops of contrast material-filled bowel were identified and bleeding points were pinpointed. CONCLUSION: GI hemorrhage can be easily detected at MR imaging if a long circulating macromolecular contrast agent is used to decrease the T1 of extravasated blood.

Animals↗
PubMed1995

Inflammation: imaging with methoxy poly(ethylene glycol)-poly-L-lysine-DTPA, a long-circulating graft copolymer.

PURPOSE: To test whether a nontargeted, long-circulating, synthetic polymer accumulates in areas of inflammation, with high capillary permeability and increased regional blood flow. MATERIALS AND METHODS: Methoxy poly(ethylene glycol)-poly-L-lysine (PL)-diethylenetriaminepentaacetic acid (MPEG-PL-DTPA) was labeled with technetium-99m for scintigraphy and with gadolinium for magnetic resonance (MR) imaging. Eleven Escherichia coli-infected rats were injected with 1.0 mCi (37 MBq) of Tc-99m-labeled MPEG-PL-DTPA for scintigraphy. Twelve rats underwent 1.5-T MR imaging after intravenous injection of gadolinium-labeled MPEG-PL-DTPA (35 mumol/kg). RESULTS: Tc-99m-labeled MPEG-PL-DTPA demonstrated nearly eight-fold higher accumulation in infected muscle when compared with normal muscle. Scintigrams and MR images showed areas of inflammation with peak accumulation at 24 hours after injection of Tc-99m- or gadolinium-labeled MPEG-PL-DTPA. CONCLUSION: Nontargeted, long-circulating, copolymers can efficiently accumulate in sites of inflammation and thus represent an alternative to inflammation-specific agents.

Animals↗
PubMed1993

Localization of a new enteric non-A, non-B [HEV] virus in target organ liver.

Thirteen Macaca mulatta monkeys were used for transmission of enteric non-A, non-B hepatitis virus (HEV) by the portal vein (PV) route. All these animals developed changes which are found in self-limiting acute viral hepatitis e.g. rise in liver enzymes, the presence of HEV specific viral particles in the stool and histological changes in the liver from 21 to 45 days after HEV inoculation. All the animals recovered completely as reflected by normalization of liver enzymes, and regenerative changes in the liver. The present report highlights the ultrastructural changes in the livers of these experimental monkeys. The histopathological changes included infiltration of lymphocytes and polymorphonucleocytes around the necrotic area, swelling of mitochondria, dilation of smooth endoplasmic reticulum (ER), and presence of 27-34 nm virus particles during the acute phase of the disease. In comparison, 9 control monkeys did not show any such histological changes.

Animals↗
PubMed1993

The v-raf oncogene enhances tumorigenicity and suppresses differentiation in vivo in a rat hepatocyte cell line.

raf oncogenes have been implicated in hepatic carcinogenesis. We studied the effects of the v-raf of murine retrovirus 3611-MSV on the growth and differentiation of a simian virus 40 (SV40)-immortalized rat liver cell line (ALB-8) which maintained many of characteristics of differentiated hepatocytes. Cells were co-transfected with v-raf and the neo gene followed by selection with G418 for transfectants. In culture, the expression of v-raf stimulated cell proliferation without altering cell morphology or expression of liver-specific genes: albumin, fibrinogen, alpha-1-antitrypsin and alpha-1-acid glycoprotein. The v-raf-transfected cells induced rapidly growing tumors in 100% of nude mice, while control DNA-transfected cells were only weakly tumorigenic, producing slowly growing tumors in 2/7 mice after a long latency. These slowly growing tumors were histologically moderately to well-differentiated hepatocellular carcinomas in which the liver-specific genes were highly expressed. In contrast, v-raf-induced tumors were histologically poorly differentiated and showed a dramatic decline in the expression of the liver-specific genes. In a tumor cell culture established from a v-raf-induced tumor, however, expression of the liver-specific genes was coordinately recovered. These observations indicate that v-raf is capable of inducing progression of SV40-immortalized hepatocytes into highly malignant cells and the progression is accompanied by loss, in vivo, of the hepatic differentiation.

Albumins↗
PubMed1990

Animal transmission of enteric non-A, non-B hepatitis infection to Macaca mulatta by faeco-oral route.

M. mulatta monkeys were inoculated faeco-orally by enteric non-A, non-B virus to study the development of clinical, biochemical, histopathological and serological changes in the blood and liver. Pooled stool samples positive for putative non-A, non-B viral antigen by micro-ELISA and aggregated viral particles by immune electron microscopy, were administered in two M. mulatta monkeys. Biochemical, histopathological and serological changes were seen in the blood and liver and excretion of 27 nm virus like particles around 27 days of inoculation in the experimental monkey but not in the control animal.

Animals↗
PubMed1990

Incidence of R-plasmids in toxigenic & non-toxigenic strains of Escherichia coli from children with diarrhoea.

Toxigenic (30) and non-toxigenic (30) multiresistant strains of Esch. coli were studied for the incidence of R-plasmids. ST+, LT+ and ST+ LT+ plasmids were produced by 66.7, 30 and 3.3 per cent of toxigenic strains, respectively. ACST was the predominant resistance pattern in both the types. Incidence of R-plasmid in the toxigenic strains was 73.3 per cent as compared to 60 per cent in the non-toxigenic strains. Non-conjugative R-plasmid was present in 10 per cent of the non-toxigenic strain. In 13.3 per cent of toxigenic Esch. coli strains along with the transfer of antibiotic resistance, the ability to produce enterotoxin was also conferred on the recipient. This suggests that the genes coding for antibiotic resistance and enterotoxin are frequently associated and can be transferred together in vitro.

Child, Preschool↗
PubMed1990

Type A behaviour, life events & myocardial infarction.

Fifty patients of myocardial infarction and 50 normal controls were studied to find out the relationship of Type A behaviour and stressful life events with myocardial infarction and its sequelae. Type A behaviour was detected in 72 per cent of patients as compared to 16 per cent in control group. Among the different components of Type A behaviour, Factor S (measuring speed and impatience) was found to be significantly higher in the study group. Patients with myocardial infarction also scored significantly high on mean frequency and stress scores on total life events as well as on various subgroups of life events. The mean anxiety and depression scores (as measured on Hamilton's anxiety rating scale and Beck's depression inventory respectively) in patients also showed statistically significant improvement with the passage of time.

Adult↗
PubMed1989

Congenital kala-azar.

An 11-month-old male infant was admitted to hospital with fever, pallor and hepatosplenomegaly, and was diagnosed as having kala-azar. The mother also suffered from kala-azar while carrying this baby. As the baby and the mother did not leave Delhi either during or after delivery, and the vector found in Delhi is not competent to transmit leishmaniasis, the infant could not have been infected by the bite of a sandfly. It therefore seems most likely that he was infected in utero--a rare route.

Adult↗
PubMed1988

An enzyme-linked immunoassay for the possible detection of non-A, non-B viral antigen in patients with epidemic viral hepatitis.

An enzyme-linked immunosorbent assay has been developed by using IgM antibodies from the acute stage as a source to capture the antigen in stools of patients with epidemic non-A, non-B (NANB) viral hepatitis. 29/69 (42.3%) of the patients and 3/9 (33.3%) contacts were positive for a suspected NANB viral antigen. However, only 1/27 (3.7%) of the negative controls drawn from amongst the patients with amoebiasis, giardiasis, hepatitis due to virus A and healthy individuals was positive for NANB antigen in the stool. The suspected NANB viral antigen was more frequently detected in stools collected between the 14th and 18th day of icteric hepatitis. The study suggests that IgM antibodies from patients with acute viral NANB hepatitis react with an antigen present in the stools of a high proportion of patients with epidemic NANB viral hepatitis. This serological test may be useful to establish the etiological diagnosis of non-A, non-B (fecal-oral) viral hepatitis. ELISA-positive stools contained 27 nm viral particles.

Antigens, Viral↗