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Biomedical subjects

A Bhatia

Publications and source records attributed to A Bhatia.

At least 91 records · Page 5Linked to original sources
PubMed1992

Antigenic diversity amongst ten geographic isolates of Plasmodium falciparum defined by merozoite invasion inhibition assay.

The extent to which human antibodies involved in functional immunity react with antigenic determinants varying between different isolates or strains of human malaria parasite Plasmodium falciparum will influence the design of vaccine against malaria. In this study, in vitro inhibition of merozoite invasion in erythrocytes by an immune human serum was used to define the antigenic differences in 10 isolates of P. falciparum from three endemic areas, i.e. Africa, South America and Southeast Asia. The serum inhibited the invasion of merozoites of all the strains but the extent of inhibition varied from low to moderate to high degree indicating antigenic differences amongst isolates of P. falciparum. The antigenic differences could not be correlated to the geographic origin of the parasite isolate.

Animals↗
PubMed1992

Cytological diversity of osteosarcoma.

Sixty three cases of clinically and radiologically diagnosed osteosarcomas were evaluated by fine needle aspiration cytology over a five year period. Adequate material was obtained in 59 cases. The sites aspirated were femur, tibia, humerus, fibula, scapula and clavicle. The mean age was 16 years. The most frequent morphological type encountered was the pleomorphic tumor (42) the other cytological types were sclerotic (10), chondroid (6), and small cell osteosarcoma (1). Hematoxylin and Eosin stain was better suited for detection of osteoid than routinely done cytological stain. The awareness of this cytological diversity is essential to avoid misinterpretation of osteosarcomas.

Adolescent↗
PubMed1991

Multiple glomangiomas of lower limb.

A young man with multiple painful nodules on the left lower limb is presented. Histology of one of the nodules proved the diagnosis of glomangioma.

Adult↗
PubMed1991

Dietary modulation of malaria infection in rats.

Feeding of wistar albino rats on low protein and energy diet (4% protein) caused suppression of parasitaemia when infected with Plasmodium berghei besides causing a depressed immune response. The refeeding of protein energy deficient rats on normal protein and energy diet (18% protein) for four weeks resulted in the normal course of parasitaemia after P. berghei infection. The present study was carried out to find the cause of suppression of malaria in protein energy deficient rats. The experiments revealed re-elevation of malaria parasitaemia when rats were fed on low protein diets supplemented with p-amino-benzoic acid (PABA). Moreover, the parasite persisted at subpatent levels in tissues in protein energy deficient rats and resulted in the development of antimalarial antibodies. Low protein energy diet could cause deficiency of certain essential nutrients required for the parasite, PABA being one of them, and hence suppresses the parasitaemia to subpatent levels. As a result, sufficient antigenic stimulus is provided to the host so that the host develops an immune response which might in turn help in further suppression of parasitaemia to subpatent levels.

4-Aminobenzoic Acid↗
PubMed1991

Light & electron microscopy of proliferating oval cells during early chemical hepatocarcinogenesis.

Early hepatic changes were studied in male albino rats (70) of Sprague Dawley strain fed a choline devoid diet containing 0.05 per cent w/w AAF (2-acetylaminofluorene) for 12 days. Proliferating periductal and ductal cells appeared in the portal area on days 1 and 3 respectively in the experimental group. On day 7, these cells infiltrated within the sinusoids of adjacent lobules up to the first one or two layers of hepatocytes. Subsequently, these cells extended up to the midzonal region on day 21 and by day 24 the entire lobule was infiltrated. Formation of duct like structures by the proliferating cells was seen on day 21. Ultrastructurally both periductal and ductal cells showed only a few organelles. Periductal and ductal cells are the earliest cells to appear in the portal area in chemically induced hepatocarcinogenesis. Its undifferentiated ultrastructure, may suggest the stem cell nature of these cells.

2-Acetylaminofluorene↗
PubMed1990

Morphological changes in the liver on chronic administration of small doses of paracetamol in albino rats.

30 male albino rats of Wistar strain were used to study the effect of repeated administration of small doses of paracetamol over a period of 24 weeks. The animals were administered 0.3 g of paracetamol orally admixed in the diet, after an overnight fast. Three animals from the test group and one control were sacrificed at the end of 4, 8, 12, 16, 20 and 24 weeks, under ether anaesthesia. Liver cell necrosis was not seen at any stage of the experiment. Fatty change was focal at 4 to 8 weeks and diffuse at 12 to 24 weeks. Chronic administration of paracetamol admixed in the diet showed less extensive changes comprising of focal ballooning degeneration. Ultrastructural changes involved mitochondria and RER. Fibrosis was not seen.

Acetaminophen↗
PubMed1989

Fine needle aspiration cytology in the diagnosis of bone tumors.

Two hundred and forty osteolytic lesions were biopsied by means of a fine needle. The procedure yielded adequate material in 92 percent of the cases. A definitive diagnosis with correct cell typing was provided in 89 per cent of the adequate samples. Processing of the aspirated clot in addition, in 142 cases, provided fragments of tumour tissue in its histological milieu, a feature lost in cytologic smears. FNAC can be effectively used in the screening of various musculo-skeletal mass lesions and their management.

Biopsy, Needle↗
PubMed1989

Synergistic promoter effect of diethylstilbesterol & phenobarbitone in diethylnitrosamine induced hepatic neoplasia in rats.

An experimental model was designed to study the role of both diethylstilbesterol (DES) and phenobarbitone (PB) singly or in combination, in diethylnitrosamine (DEN) induced hepatic neoplasia. Experimental and control rats were injected DEN (200 mg/kg) or saline, ip. Acute morphological changes were studied at days 1, 2 and 3; and at weekly intervals for 3 wk. Four weeks after DEN pretreatment the experimental and control rats were randomized into various groups and fed DES (T1), PB (T2) or a combination of both DES and PB (T3). Five rats from each experimental group were sacrificed at 10, 20 and 30 wk. Group T3 showed gross nodules with a mean nodule score of 20.5 mm at 20 wk. Nodule score in T1, T2 and T3 at 30 wk were 7, 9 and 34.5 mm respectively. The sequential morphological lesions encountered were clear cell and acidophilic foci; acidophilic, basophilic and mixed nodules. Haemorrhage within the nodules was frequent when DES was administered either alone or in combination with PB. Oval cell proliferation and cholangiocellular lesions were produced in all experimental groups. Foci and nodules generally showed loss of glucose-6 phosphatase, adenosine triphosphatase and invariable presence of gamma-glutamyl transpeptidase and glycogen. A combination of DES and PB as promoter yielded earliest and highest nodule score. This suggests that DES and PB acted synergestically as promoters or that PB caused enzyme induction thereby enhanced the promotive effect of DES.

Animals↗
PubMed1988

Protein p126: a parasitophorous vacuole antigen associated with the release of Plasmodium falciparum merozoites.

The p126 protein is synthesized by P. falciparum between the 32nd and the 36th hour of the erythrocytic cycle, and is localized in the parasitophorous vacuole. It is processed when schizonts rupture and the major fragments (50, 47 and 18 kDa), which are released into culture supernatant, have been characterized using monoclonal antibodies. The 47 kDa fragment has been mapped at the N-terminus of the molecule. The portion of the protein p126 gene coding for this fragment contains 3 introns and is characterized by a sequence coding for 6 repeats of 8 aminoacids and by repeats of TCA/T-AGT coding for a polyserine sequence of 37 serines in a row for the FCR-3 strain. The 50 kDa fragment is also found in culture supernatant when merozoites are released from mature schizonts. The incubation of mature schizonts with leupeptin inhibits the release of merozoites and, in this case, a 56 kDa intermediate product is found. In those conditions, merozoites were observed free in the erythrocyte cytoplasm, the membrane of the parasitophorous vacuole being destroyed. The 50 kDa fragment can be obtained from the 56 kDa fragment by treatment with trypsin (a protease inhibited by leupeptin). Our results suggest that the processing of the 56 kDa fragment: 1) is protease-dependent, and could depend on a trypsin-like activity; 2) cannot occur after the release of merozoites because of the protease inhibitors contained in the serum; 3) does not occur before the release of merozoites, since no processed products of the protein p126 are observed in unruptured schizonts.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1987

The stereoselectivity of four hepatic glutathione S-transferases purified from a marine elasmobranch (Raja erinacea) with several K-region polycyclic arene oxide substrates.

Product analysis by HPLC demonstrated that three hepatic cytosolic glutathione S-transferases of little skate (E-2, E-3 and E-4) were highly stereoselective, if not stereospecific, for thiol reaction at the R-configured oxirane carbons of four K-region arene oxides; pyrene 4,5-oxide, (+/-)-benz[a]anthracene 5,6-oxide, (+/-)-benzo[a]pyrene 4,5-oxide and phenanthrene 9,10-oxide. A fourth transferase, E-5, exhibited no stereopreference with pyrene 4,5-oxide or phenanthrene 9,10-oxide. Immunological and electrophoretic evidence has shown that the three enzymes exhibiting stereospecificity have a common subunit which is absent from enzyme E-5. The high stereoselectivity of the three enzymes E-2, E-3, and E-4 was accompanied by effective catalysis of the reaction of GSH with these K-region epoxides; for example, the calculated turnover number for E-4 with benzo[a]pyrene 4,5-oxide was 550.

Animals↗
PubMed1987

Immunochemical analysis of a major antigen of Plasmodium falciparum (P126) among ten geographic isolates.

Protein P126, a parasitophorous vacuole major antigen of Plasmodium falciparum and precursor of 3 major exoantigens (50, 47, and 18 Kd in strain FCR-3) has been studied in 10 culture-adapted isolates originating from various endemic areas. Two monoclonal antibodies (specific for 50 and 47 Kd exoantigens, respectively) were used to immunoprecipitate culture supernatants and parasitized erythrocytes in each case. It was observed that all the parasite isolates reacted with both monoclonal antibodies, indicating the ubiquity of the epitopes analyzed. Further, two of the exoantigens (the 50 and 18 Kd of FCR-3) were found to have a stable molecular mass in all the isolates tested, whereas, the other one (47 Kd in FCR-3) was found to have a variable molecular mass, from 47 to 50 Kd. The molecular mass of the precursor varied from 126 Kd to 128 Kd. No correlation was found between geographic origin and antigenic size.

Antibodies, Monoclonal↗