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Biomedical subjects

A N Bhisey

Publications and source records attributed to A N Bhisey.

At least 19 recordsLinked to original sources
PubMed2006

Impaired cell motility in chronic myeloid leukemic granulocytes related to altered cytoskeletal pattern.

The bactericidal activity of polymorphonuclear leucocyte (PMNL) against infection stimulates cytoskeletal changes accompanied with alteration in adhesion and locomotion. Microfilaments, the motile apparatus is known to regulate these changes by polymerization of monomeric G-actin to fibrous F-actin. PMNL from chronic myeloid leukemia (CML) patients have been reported to be defective in locomotion in response to synthetic peptide, n-formyl-methionyl-leucyl-phenylalanine (fMLP) but the mechanism leading to defective locomotion and their spatial reorganization remains unclear. Therefore, in order to study the cause of defective motility of PMNL from CML patients the spatial distribution and reorganization of microfilaments and microtubules in response to fMLP have been examined by transmission electron (TEM) and scanning electron microscopy (SEM). Under SEM, the PMNL-CML surface appeared smoother with reduced ruffling resulting in rounding off cells with lesser polarized morphology. Unstimulated PMNL from normal as well as CML subjects showed shorter and fewer microtubules and evenly distributed microfilaments as compared to fMLP stimulated PMNL. It is proposed that the cause of defective locomotion was due to reduced surface activity as a consequence of altered cytoskeletal configuration. This phenomenon seems to be related to impaired functional appendages and as a whole led to the defective cell motility and hence reduced chemotaxis in PMNL from CML patients.

Cell Death↗
PubMed2001

Effects of an aqueous extract of processed bidi tobacco on the growth of hamster tracheal epithelial cells.

Inhalation of tobacco dust is responsible for elevated genotoxicity and pulmonary ailments in workers engaged in processing tobacco for the manufacture of bidis, the Indian version of cigarettes. Tracheal tissue being the major site of interaction with tobacco dust, the effects of different concentrations of an aqueous extract of bidi tobacco (ATE) on the growth of a hamster tracheal epithelial cell line (HTE) were investigated. Colony forming efficiency assay revealed that ATE was cytotoxic only at the highest concentration of 5.0 mg/ml. In cultures treated with 1.25 mg/ml ATE, the cell doubling time and growth rate were similar to that of the controls, while a significant increase in cell doubling time (29.4+/-0.3 h vs 14.0+/-3.75 h, P<0.001) was observed at 2.5 mg/ml ATE concentration. Exposure of HTE cells to the non-toxic ATE concentration of 2.5 mg/ml was found to stimulate ornithine decarboxylase (ODC) activity, incorporation of [3H] methyl thymidine into DNA and increase in the S phase fraction was seen by flow cytometry. However, a 56% reduction in the growth rate of cultures treated with 2.5 mg/ml ATE was related to the prolongation of the traverse of cells through S phase. ATE-induced growth suppression was reversed when cultures were grown in ATE-free medium or upon repeated exposure to ATE. The findings suggest that increased tracheal cell proliferation induced by chronic inhalation of tobacco dust may contribute to the development of pulmonary disorders and possibly neoplasia in exposed individuals.

Animals↗
PubMed2000

Actin polymerization in response to different chemoattractants is reduced in granulocytes from chronic myeloid leukemia patients.

Chronic myeloid leukemia (CML), a hematopoietic stem cell disorder, is characterized by the presence of Philadelphia chromosome (Ph1). Earlier studies have shown that various functions, such as chemotaxis, fluid phase pinocytosis, phagocytosis, and degranulation in response to chemotactic peptide formyl-methionyl-leucyl-phenylalanine (fMLP), were defective in polymorphonuclear leukocytes (PMNL) from CML patients. These functions depend on actin microfilaments (MF). Further studies showed that fMLP-induced actin polymerization was lower in CML PMNL. To see if this defect is specific to stimulation by fMLP alone or is a global phenomenon involving other chemoattractant receptors, chemotaxis and actin polymerization were studied in response to fMLP, an analog of fMLP, formyl-methionine-1 aminocyclooctane 1 carboxylic acid-phenyalanine-O-methionine (FACC8), platelet-activating factor (PAF), and leukotriene B4 (LTB4). These compounds bind to different chemoattractant receptors. Chemotaxis and actin polymerization in response to all four chemoattractants were significantly lower in CML PMNL compared with PMNL from normal subjects and were differentially affected for the different chemoattractants. These results suggest a global phenomenon involving all four chemoattractant-stimulated pathways. This lower amount of F-actin may be responsible for the defective chemotaxis seen in these cells.

Actin Cytoskeleton↗
PubMed2000

Cytokeratin expression in human fetal tongue and buccal mucosa.

Expression of cytokeratins (CK), a subset of intermediate filament (IF) proteins in epithelia, is developmentally regulated. CK expression may also change after malignant transformation. Our earlier studies on CK expression in human oral tumours and pre-cancerous lesions have shown specific changes in CK expression. We analysed CK expression in human tongue and buccal mucosa (BM) in fetuses in the embryonic age group of 16 to 27 weeks using biochemical and immunohistochemical techniques to find out whether there is any similarity in CK expression in human oral squamous cell carcinomas (SCC) and fetal oral tissues. CK 1, 8 and 18 were detected in a majority of samples using both techniques. Our earlier studies had shown aberrant expression of CK 1 and 18 in many of the oral SCC and leukoplakias. Studies by immunohistochemistry showed that these different CK antigens were expressed in different cell layers. CK 1(2) were present in the stratified epithelial layers whereas CK 8 and 18 were restricted to glandular epithelium. Till 27 weeks of gestation, both tongue and BM expressed CK 1, 8 and 18 along with CK 6 and 16. Thus, fetal tissues showed some similarities in CK pattern with their respective SCC.

Electrophoresis, Gel, Two-Dimensional↗
PubMed1999

Establishment and characterization of normal and initiated hamster tracheal epithelial cell system.

The development and characterization of normal hamster tracheal epithelial (HTE) cell system and its initiated subline is described in the present study. Normal HTE cells grew in a monolayer, had a stable diploid karyotype, were anchorage dependent and non-tumorigenic. The presence of desmosomal attachments and keratin filaments confirmed the epithelial nature of these cells. An initiated subline DTC8 was isolated after treatment of HTE cells with a suboptimal dose of 9,10-dimethyl-1,2-benz[a]anthracene (DMBA). These DTC8 cells grew in a monolayer, had a higher growth rate and saturation density, were weakly anchorage independent and non-tumorigenic. Treatment of DTC8 cells with 100 ng 12-O-tetradecanoyl phorbol-13-acetate (TPA), resulted in transformation of these cells which then showed anchorage independent growth on semisolid agar and formed tumours in 85% animals. As DTC8 cells showed heterogeneity in chromosome number, they were further cloned by the limiting dilution method using gamma-irradiated hamster embryonic fibroblasts as a feeder layer. The clone H7I, isolated among these clones had all the properties of initiated cells.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1998

Cytokeratin expression in precancerous lesions of the human oral cavity.

Cytokeratin (CK) expression was studied in buccal mucosa (BM) from 20 leucoplakia and 7 submucous fibrosis patients using sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), immunoblotting and two-dimensional gel electrophoresis with iso-electric focussing (IEF) as the first dimension. Normal BM expresses CK 4, 5, 13, 14 and perhaps 19. Of 20 leucoplakia samples analysed, CK 5 was not detected in 17 samples, while CK 14 was not found in 13 samples. CK 1 and CK 8 were aberrantly expressed in six and seven samples, respectively. CK expression in contralaterally collected uninvolved tissues from 3 patients showed a normal pattern in two samples. Non-expression of CK 5 was observed in five of seven submucous fibrosis samples, while CK 14 was not detected in only two samples. CK 8 was aberrantly expressed in three samples. All the leucoplakia patients were chronic tobacco chewers. Thus, non-expression of CK 5 may be an early event occurring in tobacco-associated pathological changes in the BM.

Biomarkers, Tumor↗
PubMed1996

Granulocytes from chronic myeloid leukemia (CML) patients show differential response to different chemoattractants.

Binding of chemoattractant to polymorphonuclear leukocytes (PMNL) triggers a series of events like polymerization of actin and tubulin, orientation of cells, chemotaxis, increase in fluid pinocytosis and phagocytosis, and stimulation of microbicidal pathways which includes lysosomal degranulation and generation of reactive oxygen species. Earlier studies from our laboratory have shown that stimulation of chemotaxis, fluid pinocytosis, and actin polymerization of CML PMNL in response to a synthetic chemotactic peptide formyl-methionyl-leucyl-phenylalanine (fMLP) is significantly lower than that in normal PMNL. It is not known whether this lower response of CML PMNL to fMLP is a global phenomenon involving different chemoattractant receptors or is restricted to the fMLP pathway. We have evaluated chemoattractant induced degranulation process in normal and CML PMNL to fMLP, platelet activating factor (PAF), leukotriene B4 (LTB4), and an analogue of fMLP viz formyl-methionine-1 aminocyclooctane 1 carboxylic acid-phenylalanine-O-methionine (FACC8) using release of lysozyme as a parameter. We find that after stimulation with fMLP and FACC8, the mean percent release of lysozyme was significantly lower in CML PMNL as compared to that in normal cells (P < 0.001). There was no significant difference between the two after stimulation with PAF and LTB4. The results indicate that the fMLP pathway is suppressed in CML granulocytes whereas PAF and LTB4 pathways appear unaltered in these cells. We therefore also studied the kinetics of peptide-receptor interaction with a labelled hexapeptide fNLPNTL which binds to the fMLP receptor. Our results show that the number of fMLP receptors/cell is significantly lower in CML PMNL (P < 0.05) than in normal PMNL, while their affinity constants and dissociation constants were comparable.

Chemotactic Factors↗
PubMed1996

Cytogenetic studies on a patient with prepubertal breast cancer: a case report.

Cytogenetic studies were carried in a 10 year old girl with prepubertal breast cancer for assessing inherited genetic susceptibility to chromosome breakage. The girl presented with a tumour in the left breast. Histologically it was diagnosed as secretory carcinoma (SC). Chromosome anomalies observed in phytohemagglutinin (PHA-P) stimulated lymphocytes were del(2)(q33), del(3)(p24), del(7)(q22) and dup(12)(p11p12). The regions involved have been reported in breast tumors. These loci, detected in peripheral blood lymphocytes (PBL), could be the sites susceptible to breakage, its subsequent effect being manifested in the target (breast) tissue.

Breast Neoplasms↗
PubMed1996

Cytokeratin expression in squamous cell carcinomas of the tongue and alveolar mucosa.

Cytokeratins (CK), the intermediate filament markers for epithelial cells were analysed in 23 squamous cell carcinomas (SCC) of the tongue and 11 SCC of the alveolar mucosa (AM) by SDS-PAGE, immunoblotting and two dimensional gel electrophoresis. Normal human adult ventral tongue expresses CK nos 4, 5, 6, 13, 14, 16 (17) while the dorsal tongue expresses CK nos 1, 5, 6, 10, 14, 16 (17). CK 5 and CK 14 were not detected in a majority of samples and CK 18, a marker of simple epithelia, was aberrantly expressed in 18 samples. Normal human adult AM expresses CK nos 4, 5, 6, 13, 14, 16 (17). Among 11 SCC of AM, CK 4 and CK 5 were detected in only two samples each. CK 1 and CK 10 were aberrantly expressed in nine and one samples, respectively. The basic CKs such as CK 4, 5 and 14 were not expressed in SCC at both these sites while others like CK 1 and 18 were aberrantly expressed. Thus, non-expression of basic keratin, CK 5, of the oral lining epithelia and aberrant expression of simple epithelial keratins seem to be the major events in malignant transformation in the oral epithelia.

Adult↗
PubMed1995

Chronic myeloid leukemia granulocytes exhibit reduced actin polymerization after chemotactic peptide stimulation.

Polymorphonuclear leukocytes (PMNL) from chronic myeloid leukemia (CML) patients are defective for chemotaxis in response to the synthetic chemotactic peptide n-formyl-methionyl-leucyl-phenylalanine (fMLP) as compared to normal PMNL. The present study investigated whether the defective chemotactic response was mediated through altered actin polymerization induced with fMLP. Granulocytes isolated from seven normal subjects and seven CML patients were stimulated with fMLP and lysed with Triton containing buffer at time points of 0, 30 seconds, and 1, 2, and 10 minutes. The Triton insoluble cytoskeleton containing polymerized actin was analyzed by SDS-PAGE and densitometry. The CML PMNL polymerized significantly lesser actin than normal PMNL on stimulation with 10 nM (p > 0.05) and 1 nM (p > 0.01) fMLP. This lower actin polymerization observed in fMLP-stimulated CML PMNL may be responsible for the defective chemotaxis seen in these cells.

Actins↗
PubMed1994

Karyotypic findings as an independent prognostic marker in chronic myeloid leukaemia blast crisis.

Fifty-three patients with Ph positive chronic myeloid leukaemia in blastic phase were studied. Additional abnormalities were found in 29 (55%) patients and were more common in myeloid (64%) than lymphoid (45%) blast crisis. The most frequent were +Ph (32%), +8 (28%), +19 (19%), +20 (9%) and +21 (9%). i(17q) (9%) was associated with thrombocytopenia (5/5) and basophilia (2/5). The incidence of additional abnormalities was higher in patients treated with busulphan (70%) than hydroxyurea (44%). No significant differences were noted in the mean values of the clinical and haematological findings recorded at blast crisis between patients with only Ph positive (PP) cells and those with additional abnormalities (AP + AA). Univariate analysis identified karyotypic findings as an independent prognostic marker indicating its significance in assessing the response to therapy and survival after the onset of transformation.

Adult↗
PubMed1994

Flow cytometric DNA analysis of squamous cell carcinomas of the oral cavity: correlation with clinical and histopathological features.

DNA content was measured in 68 squamous cell carcinomas (SCC) of the oral cavity by flow cytometry. Samples fixed in 95% alcohol and disaggregated with 0.5% pepsin were stained with 4,6-diamidino-phenylindole (DAPI) for flow cytometry. The tumours were classified according to the TNM classification--1987, and graded histopathologically. A positive correlation between tumour size and ploidy status was observed. Poorly differentiated tumours were mainly non-diploid (P < 0.01, chi 2). A majority of the node positive (N+) tumours were non-diploid (P < 0.05). It was possible to distinguish diploid, N+, T4 tumours from diploid, N-, T4 tumours by their higher S-phase fraction (SpF). SpF was also a useful parameter to differentiate diploid, N+ tumours from diploid, N- tumours among the moderately differentiated (MD) SCC. These results suggest that ploidy and SpF can be useful correlates of tumour behaviour.

Adult↗
PubMed1993

Chronic myeloid leukemia granulocytes have lower amounts of cytoplasmic actin.

Chronic myeloid leukemia (CML) granulocytes had earlier been shown to be defective in microfilament mediated phenomena such as chemotaxis and fluid phase pinocytosis when compared to normal granulocytes. The present studies were carried out to determine whether a quantitative alteration in actin or a change in isoform status could be responsible for some of the defects. Relative proportions of beta and gamma isoforms were found to be unaltered between normal and CML granulocytes. The amount of actin was significantly lower in CML cells. When the actin was expressed as percent of total protein in the granulocytes, it was found to be significantly lower in CML cells. The lower amount of actin may be responsible for some of the defects seen in CML cells.

Actins↗
PubMed1992

Fluid pinocytosis and esterase-oxidase in chronic myeloid leukemic granulocytes are differentially stimulated by chemotactic peptide.

Binding of a chemotactic peptide, n-formyl-methionyl-leucyl-phenylalanine (FMLP) to polymorphonuclear leukocytes (PMNL) leads to a series of biochemical and functional events. We have studied stimulation of fluid phase pinocytosis (FP), esterase and oxidase by FMLP in CML PMNL, by flow cytometry. Stimulation of FP in CML PMNL was lower than that in normal PMNL but, stimulation of esterase and oxidase was comparable to that in normal PMNL. Thus, early response to FMLP which is dependent on the integrity of actin network seems to be defective in CML PMNL.

Chemotaxis, Leukocyte↗
PubMed1992

Cytoplasmic microtubule assembly is altered in cytoplasts.

Nucleation of microtubule (MT) organization of the cytoplasmic microtubule complex (CMTC) from the microtubule organizing centres (MTOC) was studied in enucleated cytoplasts of human diploid fibroblast (MRC-5) and mouse peritoneal macrophages in culture. Cytoplasts of both cell types could not organize the complete CMTC. Aberrant MT patterns were seen in MRC-5 cells while mouse macrophages showed occurrence of few short MT. The studies suggest that nucleus may have a role in determining CMTC.

Animals↗
PubMed1992

DNA analysis of breast cancer by flow cytometry & correlation with other prognostic parameters.

Flow cytometric estimation of DNA content (ploidy and S-phase fraction--SpF) was done on breast cancer tissues from 171 patients. Twenty eight per cent of the tumours were diploid and 72 per cent were aneuploid. SpF was measurable in 82 DNA histograms; of these 22.4 per cent had SpF less than 10 per cent, 34.1 per cent had SpF between 10-20 and 43.5 per cent had SpF greater than 20 per cent. The mean SpF of the measurable histograms was 19.01 per cent with a range 1.78 to 45.19 per cent. A significant correlation between DNA ploidy and SpF was observed (P less than 0.01). Eighty nine per cent of diploid tumours had SpF less than 10 per cent and 73 per cent of aneuploid tumours had SpF greater than 20 per cent. A significant correlation was also found between ploidy and SpF and oestrogen receptor (ER) status of the tumours (P less than 0.05) and between SpF and progesterone receptor (PgR) status of the tumours (P less than 0.05), but not between ploidy and PgR status of the tumours. A significant direct correlation was observed between SpF and tumour grade (P less than 0.05), but not between ploidy and tumour grade. No correlation was observed between DNA ploidy and SpF and tumour type, tumour size, axillary lymph node involvement, age and menopausal status of the patients. Although the incidence of breast cancer is one-third of that reported in the Western countries, there is apparently no biological difference between the various parameters studied.

Aneuploidy↗
PubMed1991

Regulation of cytoplasmic microtubule complex organisation in somatic cell hybrids.

Regulation of cytoplasmic microtubule complex (CMTC) organization was studied in cultured human fibroblasts and mouse macrophages by somatic cell fusion. The heterokaryons stained with antitubulin antibody had fibroblast-like CMTC even 72 hours after fusion. There was no change in CMTC pattern when more than one macrophage had fused with one fibroblast. However, the macrophage CMTC was expressed in heterokaryons when the former were located at the periphery of the heterokaryon. To evaluate the role of existing CMTC in determining the CMTC of heterokaryons, the heterokaryons were treated with nocodazole to depolymerize the CMTC and then allowed to recover. The resultant CMTC was fibroblast like.

Animals↗