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Biomedical subjects

G Singh

Publications and source records attributed to G Singh.

At least 559 records · Page 31Linked to original sources
PubMed1989

Drug resistance and lecithinase activity of Yersinia enterocolitica isolated from buffalo milk.

Two-hundred-and-seven samples of raw buffalo milk and 60 samples of pasteurized buffalo milk were screened for presence of Yersinia enterocolitica. The prevalence of Y. enterocolitica was found to be 24.1% in raw milk, however, no isolation could be made from the pasteurized milk samples. Cold enrichment in trypticase soy broth and alkali treatment methods were followed in this study. The majority of the isolates (62%) were found sensitive to all the antibiotics used and only a few (16%) were resistant to two or more than two antibiotics. The incidence of Y. enterocolitica showed seasonal variations. Incidence was much higher (25-50%) during the winter season as compared to the summer (0-17%). The incidence of lecithinase production was high (40-50%) in Yersinia isolates resistant to one or two antibiotics.

Animals↗
PubMed1989

A possible cellular mechanism of cisplatin-induced nephrotoxicity.

Cisplatin, a relatively new antitumor agent, is associated with renal function impairment. The mechanism of cisplatin-induced nephrotoxicity is unknown. A mouse model was used to examine nephrotoxicity induced by cisplatin. This study demonstrates both morphologically and biochemically that mitochondrial damage may be associated with cisplatin-induced cellular toxicity. The morphological changes are evident after 72 h following a single 10 mg/kg i.p. dose of cisplatin. Biochemical changes also follow the morphological abbreviations. In vitro incubation of cisplatin with cells also shows a decline in Rhodamine 123 fluorescence with time, which is indicative of mitochondrial damage. The present findings suggest the possibility that the nephrotoxic effects of cisplatin may be related to a mitochondrial damage.

Animals↗
PubMed1989

Cataract surgery and intraocular lens implantation in patients with uveitis.

The authors reviewed the outcome of extracapsular cataract extraction (ECCE) in 44 eyes of 38 patients with uveitis. Thirty-two of the 44 eyes received a posterior chamber lens implant; 87% of these achieved a stable visual acuity of 20/40 or better. Sixty-seven percent (8 of the 12 eyes) not receiving an implant achieved this level. The authors' results and current literature suggest that absolute control, preoperatively and postoperatively, of all uveitis inflammation and careful selection of patients as lens implant candidates are crucial for successful cataract surgery in uveitis patients. Complete removal of lens cortex and placement of an all-PMMA posterior chamber lens within the capsular bag are also believed to be important.

Adult↗
PubMed1989

Partial purification and characterization of phospholipase C from Yersinia enterocolitica.

About 34% of the strains of Yersinia enterocolitica isolated from raw milk were found to produce lecithinase. A selected strain produced phospholipase C at 22 degrees C and 37 degrees C; production was optimum at 37 degrees C in the stationary phase (14-16 h). A decrease in phospholipase C activity at various storage temperatures (-5 degrees C, 4 degrees C, 37 degrees C) was also observed, although the enzyme was active over a wide range of temperature (5-65 degrees C) and pH (3.5-7.5). The phospholipase C was partially purified by ammonium sulphate precipitation and Sephadex column chromatography, and characterized.

Animals↗
PubMed1989

Ability of prostaglandin to reduce ethanol injury to dispersed chief cells from guinea pig stomach.

To determine whether prostaglandin exerts a direct action on individual gastric epithelial cells that protects them from ethanol-induced injury, dispersed chief cells from guinea pig stomach were pretreated with 16,16-dimethyl-prostaglandin E2 (dmPGE2) or placebo before incubation with ethanol or control. Cell injury was assessed in terms of exclusion of Fast Green dye, release of lactate dehydrogenase, alterations of ultrastructure, and pepsinogen secretion stimulated by a variety of secretagogues. Of chief cells 60 +/- 2% were stained by Fast Green if incubated with 10% ethanol for 1 h after pretreatment with placebo, whereas only 38 +/- 1% of cells showed Fast Green staining when pretreated with 2.6 microM dmPGE2 before ethanol exposure. Similarly, 63 +/- 2% of cellular lactate dehydrogenase was released from chief cells pretreated with placebo compared with 36 +/- 4% of lactate dehydrogenase released from cells pretreated with 2.6 microM dmPGE2 (P less than 0.01). The prostaglandin's protective effect persisted throughout a 6-h incubation with ethanol. Scanning and transmission electron micrographs demonstrated disintegration of chief cells pretreated with placebo before ethanol exposure, whereas ultrastructural architecture was relatively preserved among chief cells pretreated with dmPGE2. Preincubation with 8 or 10% ethanol inhibited the subsequent stimulation of pepsinogen secretion caused by carbachol, cholecystokinin, A23187, 12-O-tetradecanoylphorbol 13-acetate, forskolin, or 8-bromoadenosine 3',5'-cyclic monophosphate. Pretreatment with dmPGE2 did not reduce the ethanol-induced inhibition of secretion stimulated by any of these secretagogues. These data indicate that dmPGE2 significantly reduces ethanol-induced damage to dispersed chief cells in terms of alterations of membrane permeability and ultrastructure but does not prevent the ethanol-induced impairment of pepsinogen secretion. These findings provide evidence that dmPGE2 exerts a direct but limited protective action on the gastric chief cell, independent of vascular, paracrine, or neural actions.

16,16-Dimethylprostaglandin E2↗
PubMed1989

Cholecystokinin-induced desensitization of pepsinogen secretion from chief cells.

When dispersed chief cells from guinea pig stomach were first incubated with cholecystokinin (CCK), washed, and then reincubated with CCK in fresh incubation solution, the stimulation of pepsinogen secretion and the rise in intracellular calcium concentration during the second incubation were reduced. CCK did not cause residual enzyme secretion but caused desensitization that was rapid, temperature dependent, dependent on extracellular calcium, reversible with time, and prevented but not reversed by CCK receptor antagonists. Cholecystokinin octapeptide (CCK-8) caused desensitization over the same range of concentrations that stimulate pepsinogen secretion, whereas the concentration of gastrin required to cause maximal desensitization was greater than that required to cause maximal stimulation of enzyme secretion. CCK-8 caused heterologous desensitization of pepsinogen secretion stimulated by agonists that interact with receptors to cause mobilization of cellular calcium and activation of protein kinase C or by agonists that bypass receptors to activate these mediators directly; however, CCK-8 did not induce desensitization of the stimulation caused by any secretagogue whose actions are mediated by adenosine 3',5'-cyclic monophosphate. Because CCK-8 caused greater desensitization of secretion stimulated by agonists that interact with receptors than by agonists that bypass receptors, it is likely that receptor modulation as well as a postreceptor action contribute to the ability of CCK to cause desensitization of pepsinogen secretion from chief cells.

Animals↗
PubMed1989

Toxicological evaluation of a poisoning attributed to ingestion of malathion insect spray and correlation with in vitro inhibition of cholinesterases.

A 24-year-old Caucasian male was found dead from unknown causes at his farm home. At the scene, partially filled bottles of ORTHO Malathion 50 Insect Spray and CLOROX bleach were found. At the time of autopsy, a strong odour of a petroleum based product was prominent in the small intestine and in the liquid stool. A similar odour was also present in the liquids of both bottles. Generalized visceral and vascular congestion with oedema in various tissues was markedly present. Toxicological analysis of the gastric contents, intestinal contents, bile and liquid samples from the malathion and bleach bottles revealed the presence of malathion in the concentrations of 2.1 g/kg, 98 g/kg, 570 mg/l, 54% and 11%, respectively. In the blood and urine, malathion was not detected. Xylenes and other common volatile components of the spray were detected in the liquids from the bottles and in the gastric and intestinal contents. The ability of the blood and bile samples to inhibit, in vitro, rat serum cholinesterase and electric eel acetylcholinesterase was consistent with their malathion concentrations as the bile inhibited both enzymes, while the blood did not. These findings conclude that the death was associated with the ingestion of a commercial malathion insect spray.

Acetylcholinesterase↗
PubMed1989

Immunohistochemical demonstration of Clara cell antigen in lung tumors of bronchiolar origin induced by N-nitrosodiethylamine in Syrian golden hamsters.

Both alveolar type II cells and Clara cells have been suggested as cells of origin of human bronchioloalveolar lung carcinomas and other pulmonary neoplasms, based on the presence of cell specific markers identified by immunocytochemical methods. Alveolar type II cell origin of solid and papillary lung tumors of the mouse has been demonstrated, and Clara cells have been suggested as cell of origin for hamster pulmonary neoplasms. Therefore, chemically induced bronchiolar hyperplasias and pulmonary neoplasms of Syrian golden hamsters were analyzed by avidin-biotin immunohistochemistry to localize a hamster-specific Clara cell antigen (CCA) and keratin. The hamsters had been treated subcutaneously with multiple doses of N-nitrosodiethylamine (NDEA). Proliferative lesions of low cuboidal, tall columnar, or pleomorphic cells were present within bronchioles or adjacent to airways in the alveolar parenchyma. Frequently areas of squamous cell differentiation were present focally or diffusely that were immunoreactive for cytokeratin. Immunoreactivity for cytokeratin was also noted for hyperplastic bronchiolar neuroepithelial bodies. Cellular hyperplasias extending out into the alveolar parenchyma contained ciliated cells and frequently consisted of cells immunoreactive for CCA, showing them to be of bronchiolar Clara cell origin. Tumors developed from bronchiolar cell hyperplasias localized within bronchioles and from bronchiolar cells lining former alveolar walls. Neoplastic growth patterns were tubulo-papillary, forming loose networks or densely cellular areas. Immunoreactivity for cytoplasmic CCA was found in 50% of the tumors and was seen most frequently in small cuboidal cells and larger, vacuolated cells scattered throughout the neoplasms. In summary, evidence is presented that NDEA-induced pulmonary tumors of the Syrian golden hamster originated from cells lining bronchioles and from extrabronchiolar Clara cell hyperplasias of the terminal bronchioles. As the pulmonary tumors of the hamsters progressed towards a squamoid cell type, CCA was no longer detectable but cells became immunoreactive for keratin.

Animals↗
PubMed1989

Prevalence of PPNG strains & in vitro sensitivity pattern of Neisseria gonorrhoeae in Varanasi (Uttar Pradesh, India).

Forty one consecutive gonococcal isolates were tested by disc method for their sensitivity to penicillin and seven other antimicrobials. Nineteen (46.34%) strains of N. gonorrhoeae were found to be relatively resistant to penicillin (MIC over 0.25 IU/ml) including 2 (4.88%) strains with complete resistance to penicillin (MIC over 1 IU/ml). None of the gonococcal strains tested was penicillinase-producing (PPNG). A decline in the proportion of sensitive strains of gonococci with a non-significant rise in median value of MIC for penicillin from 2.16 IU/ml in 1980-81 to 2.52 IU/ml in 1986-87 and other antimicrobials was observed.

Anti-Bacterial Agents↗
PubMed1989

Hormone profile in leprosy.

Hormone profile were carried out in 35 male cases of leprosy. They were divided into tuberculoid leprosy, borderline leprosy, lepromatous leprosy and lepra reaction. Serum testosterone, follicle-stimulating hormone, Luteinizing hormone, and Oestradiol level were measured in these cases of leprosy. It was observed that serum testosterone were significantly low in lepromatous leprosy (P less than 0.001) and lepra reaction (P less than 0.01). The serum levels of follicle-stimulating hormone and luteinizing hormone were significantly high in lepromatous leprosy (P less than 0.02) and lepra reaction (P less than 0.05). Serum Oestradiol was raised in approx. 60% cases in borderline leprosy, lepromatous leprosy and lepra reaction.

Adult↗
PubMed1989

Immune status of volunteers one year after administration of Japanese encephalitis vaccine produced in India.

The immune status of 40 volunteers who received the full course of Japanese encephalitis (JE) vaccine a year earlier and 15 individuals who had received only a booster dose at the same time, was studied by estimating the level of persistence of protective antibody in the sera. All the sera showed persistence of 100 per cent seroconversion rate. Individuals who had the full course of vaccination still had high levels of antibody (mean 2.8 Iog10); however there was a fall of 0.8 Iog10 from the post-booster level. Volunteers who had received only a booster dose, also showed persistence of high level of protective antibody (mean 2.4 Iog10), a drop of 0.9 Iog10 from the post-booster level. Neutralizing (N) antibody estimated using Dibrugarh (7812474) strain of JE virus also demonstrated persistence of high level of protective antibody against this virus (mean 2.4 Iog10). Persistence of high level of protective antibody against homologus and heterologus (Dibrugarh) virus strains and absence of vaccine related side-effects even one year after administration of JE vaccine produced in India, demonstrates the immunizing potency and safety of this new vaccine.

Adolescent↗
PubMed1989

Asplenia syndrome.

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Consanguinity↗
PubMed1989

Bacteriology of pyodermas and antibiograms of pathogens.

One hundred and seventy six cases of various clinical types of pyodermas were investigated to find the causative organism of the disease. Folliculitis formed the largest clinical group followed by infectious eczematoid dermatitis, secondary infection, furuncles, impetigo, ecthyma and carbuncle in descending order of frequency. A total of 189 micro-organisms were isolated from the specimens examined. A single infecting organism was isolated from 74.43% and more than one type of organism from 16.48% of cases. Coagulase positive staphylococcus (73.02%) was the predominant species followed by beta-haemolytic streptococcus (26.98%). Coagulase positive staphylococcus was isolated from 109 (61.93%), beta-haemolytic streptococcus from 22 (12.5%) and both these organisms from 29 (16.48%) cases. The antibiotic resistance pattern showed maximum resistance to penicillin followed by ampicillin. None of the strain was found to be resistant to kanamycin. Low percentage of strains were found to be resistant to streptomycin, oxytetracycline, trimethoprim, cloxacillin, erythromycin, chloramphenicol, cephalexin, gentamycin and neomycin.

Ampicillin↗
PubMed1989

Carboxyhaemoglobin and serum cholesterol levels in smokers.

Carboxyhaemoglobin (COHb) and serum cholesterol levels were studied in twenty five chronic smokers, smoking different quantities of cigarettes, biris and "hooka" for more than ten years and compared with equal number of age and sex matched non-smoker controls. COHb levels were found to be significantly higher (P less than 0.001) in chronic smokers as compared to non-smokers while no significant difference (P greater than 0.1) was found in serum cholesterol levels between the two groups. Cigarette smokers had a higher COHb level as compared to biris smokers (P less than 0.001).

Adult↗