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Biomedical subjects

F Ahmad

Publications and source records attributed to F Ahmad.

At least 109 records · Page 6Linked to original sources
PubMed1993

Screening of some Turkish medicinal plants for their analgesic activity.

Nine crude extracts of various parts of eight medicinal plants from different regions of Turkey were evaluated for their analgesic activities by tail flick method in mice. The analgesic activities of these extracts were compared with acetylsalicylic acid (300 mg/kg) which is used as a standard drug. Extracts were given orally in doses of 300, 500 and 1000 mg/kg. 0.9% saline was also administered in control group of animals. Results showed that four extracts were having highly significant analgesic activity at all the three doses tested. Three showed significant effects at higher doses while two extracts did not show any significant results.

Journal Article↗
PubMed1992

Reversed-phase chromatographic method for specific determination of glutathione in cultured malignant cells.

A chromatographic method for the specific determination of glutathione in malignant cell lines is described. The method is based on the ability of glutathione-S-transferase to specifically and quantitatively conjugate glutathione to 1-chloro-2,4-dinitrobenzene and chromatographic quantitation of the resultant conjugate, dinitrophenyl-S-glutathione, by reversed-phase liquid chromatography. The assay can be performed on 20,000 g supernatants of cell homogenates without acid extraction. 2-Mercaptoethanol, a sulfhydryl compound often used as a thiol-protective agent to preserve enzymatic activities of a number of enzymes, did not interfere with glutathione determination by this method. The dinitrophenyl-S-glutathione isolated from either standard glutathione samples or from cell homogenates was shown to be identical to authentic dinitrophenyl-S-glutathione using mass spectrometry. Recovery of glutathione in standard samples by the current method was identical to that determined using 5,5'-dithiobis(2-nitrobenzoic acid). Exogenous glutathione added to supernatants of cell homogenate in the presence or absence of 2-mercaptoethanol was also completely recovered.

Chromatography, High Pressure Liquid↗
PubMed1992

Determining stability of proteins from guanidinium chloride transition curves.

The guanidinium chloride (GdmCl) denaturation of RNAase A, lysozyme and metmyoglobin was investigated at several pH values by using absorbance measurements at 287, 300 and 409 nm respectively. From these measurements the free-energy change on denaturation, delta Gapp., was calculated, assuming a two-state mechanism, and values of delta Gapp. at zero concentration of the denaturant were measured. For each protein all delta Gapp. values were adjusted to pH 7.00 by using the appropriate relationship between delta Gapp. and pH. Dependence of the adjusted delta Gapp. value on GdmCl concentration increases for metmyoglobin and decreases for the other two proteins as the denaturant concentration decreases. It has been shown that these are expected results if the presence of the acid-denatured state during the GdmCl denaturation of proteins is considered.

Drug Stability↗
PubMed1991

Use of ciprofloxacin to control a Salmonella outbreak in a long-stay psychiatric hospital.

An outbreak of diarrhoea due to Salmonella virchow phage type 8 occurred in a major block of a large psychiatric hospital. The two other major blocks of the hospital remained unaffected. No source of infection was identified and the epidemiological investigations pointed to cross-infection as the mode of transmission. Infection control measures were implemented at an early stage but a total of 55 patients and four members of staff were affected. The disease was self-limiting and of short duration. During the course of the outbreak, Salmonella typhimurium phage type 66 also emerged as a pathogen and was isolated from the stools of symptomatic cases with diarrhoea. Owing to the size of the hospital, the lack of facilities for infection control, the nature of the patients' illnesses and an increasing number of affected patients, it was decided to treat all symptomatic and asymptomatic patients with oral ciprofloxacin 500 mg twice daily for 7 days. A quantitative stool culture for salmonellae was undertaken on days 3, 7, 10, 30, 60 and 90 from the start of treatment. All patients' and staff's stool cultures became negative on day 7 and remained negative for a period of 6 months during follow-up. We conclude that cross-infection outbreaks due to Salmonella spp. in psychiatric and geriatric hospitals can be controlled by isolation in a designated ward and supportive therapy, together with ciprofloxacin treatment.

Adult↗
PubMed1991

Mammalian pyruvate carboxylase: effect of biotin on the synthesis and translocation of apo-enzyme into 3T3-L adipocyte mitochondria.

The effect of biotin on the induction (and possible requirement for uptake into mitochondria) of apopyruvate carboxylase has been examined in 3T3-L adipocytes. Cells fed biotin-sufficient medium contained only holoenzyme in mitochondria and no apoenzyme was detected. The amount of apoenzyme elaborated in biotin-deficient 3T3-L adipocytes was comparable to the holopyruvate carboxylase protein found in cells maintained on biotin-sufficient medium. Like the holoenzyme, the apoenzyme was detected exclusively in the mitochondrial fraction of 3T3-L adipocytes. This indicates that the synthesis of apopyruvate carboxylase and its translocation into mitochondria occur independently of the cofactor, biotin.

Adipose Tissue↗
PubMed1991

Transmission of Salmonella worthington by oropharyngeal suction in hospital neonatal unit.

An outbreak of Salmonella worthington infection in a neonatal unit occurred in a pediatric ward of Holy Family Hospital, Rawalpindi, Pakistan. The index case was a prematurely born male child from whose clinical specimens S. worthington was recovered. After this finding 40 infants kept in that nursery were included in an investigation. Major symptoms were diarrhea, septicemia and jaundice. Three developed meningitis. Disease morbidity rate was 45% and mortality occurred in 16.6% of the total positive cases. The source of infection was traced to a contaminated rubber tubing of a suction apparatus which was used for oropharyngeal suction of the babies. S. worthington was recovered from the clinical specimens of all 18 babies who received suction. Multiple drug resistance of these S. worthington strains was found.

Cross Infection↗
PubMed1991

Lipid contents of marine fish: Carcharhinus melanopterus (Black Shark) and Lutjanus johnii (Hira).

Total lipid composition of liver oil of two marine fish Carcharhinus melanopterus (Black Shark) and Lutjanus johnii (Hira) was determined. The fatty acid contents of total liver lipids were identified through gas chromatography-mass spectrometry. It was found that fatty acid methyl eaten mainly consist of myristic, pentadecylic, palmitic, stearic acids as saturated, and palmitoleic, oleic, elaidic, eicosapentaenoic, docosahexaenoic, and clupanodonic acids as unsaturated components. Appreciable quantities of polyunsaturated fatty acids (PUPA) and omega-3 fatty acids were detected.

Journal Article↗
PubMed1991

Effect of (-)epicatechin on cAMP content, insulin release and conversion of proinsulin to insulin in immature and mature rat islets in vitro.

(-)Epicatechin, an active principle in the water extract of the bark of Pterocarpus marsupium increases the cAMP content of the islets which is associated with the increased insulin release, conversion of proinsulin to insulin and cathepsin B activity. The response of the islets to the (-)epicatechin stimulation is more pronounced in immature (one month old) than in mature (12 month old) rats.

Aging↗
PubMed1990

Management of institutional outbreaks of Salmonella gastroenteritis.

The number of reports of outbreaks of salmonella gastroenteritis in hospitals has decreased since 1984 but the number of outbreaks in institutions such as old peoples' homes have increased during 1988. Foods, particularly chickens, remain a source of salmonellae and particular attention has to be paid to training and practices in food preparation areas. Staff who are convalescent are very unlikely to be sources of salmonella and do not need to be excluded unless they handle food that receives no further cooking. Outbreaks that do occur can usually be controlled by patient isolation and good control-of-infection measures and an effective Major Outbreak Control Plan is necessary. In some large old hospitals cross infection outbreaks may continue despite good control-of-infection measures. Antibiotics have been contraindicated in the treatment of salmonella gastroenteritis, but the new 4-quinolone antibiotics have demonstrated potential. Ciprofloxacin was used successfully in two outbreaks of salmonella gastroenteritis at a dose of 500 mg bd orally for seven days. Relapses did not occur and resistance did not develop. Ciprofloxacin should be considered as a therapeutic adjunct to control of infection measures in cross infection outbreaks in these situations.

Anti-Bacterial Agents↗
PubMed1990

Vanadate augments insulin binding and prolongs insulin action in rat adipocytes.

Vanadate has been documented to inhibit tyrosine phosphatase activity and to have insulin-mimetic effects. However, oral administration to hypoinsulinemic diabetic rats in vivo lowers blood glucose at serum concentrations of vanadate that have minimal insulin-like effects in vitro. We, therefore, investigated the effect of low concentrations of vanadate on insulin binding, processing, and action. Preincubation of rat adipocytes for 2 h at 37 C with 10-200 microM vanadate resulted in a dose-dependent increase in [125I]insulin binding at 37 C to a maximum of 45% above the control value. Total cell-associated radioactivity and internalized (acid-resistant) hormone were similarly increased. Binding studies at 15 C in the presence of potassium cyanide revealed that this effect was associated with an increase in insulin receptor affinity. Consistent with these results, vanadate affected binding at 37 C only at low concentrations of insulin. Preloading adipocytes for 8 min with 0.4 ng/ml [125I]insulin revealed that vanadate slowed the rate of release of internalized hormone (50% release; 9.0 min vs. 12.5 min). The proportion of [125I]insulin released in intact form (trichloroacetic acid precipitable) was significantly increased by vanadate up to 15 min. Preincubation of adipocytes with vanadate resulted in an apparent increased sensitivity, with a shift to the left in the dose-response curve of insulin-stimulated lipogenesis (ED50, 0.2 vs. 0.08 ng/ml). Furthermore, vanadate maintained maximum insulin-stimulated lipogenesis after extensive washing to remove insulin. These effects could not be accounted for by the insulin-mimetic effect of vanadate alone. We conclude that 1) low concentrations of vanadate (less than 200 microM) increase insulin receptor affinity and consequent insulin uptake in rat adipocytes; 2) the excess cell-associated insulin exists largely as intact hormone; and 3) the increased binding at low insulin concentrations results in an apparent increase in insulin sensitivity. Vanadate at low concentrations also prolongs insulin action. Whether tyrosine phosphatase inhibition is the basic biochemical mechanism remains to be determined.

Adipose Tissue↗
PubMed1989

Chemical events in chloropropionyl coenzyme A inactivation of acyl coenzyme A utilizing enzymes.

Incubation of 3-chloropropionyl-CoA with 3-hydroxy-3-methylglutaryl-CoA synthase results in exchange of the C2 proton with solvent as inactivation of enzyme proceeds. This enzyme is also inhibited by S-acrylyl-N-acetylcysteamine; the limiting rate constant for inactivation by the acrylyl derivative (0.36 min-1) slightly exceeds the value measured for chloropropionyl-CoA (0.31 min-1). These observations support the intermediacy of acrylyl-CoA in the chloropropionyl-CoA-dependent inactivation of hydroxymethylglutaryl-CoA synthase. Inhibition of fatty acid synthase by chloropropionyl-CoA is primarily due to alkylation of a reactive cysteine, although secondary reaction with the enzyme's pantetheinyl sulfhydryl occurs. Modification of fatty acid synthase by S-acrylyl-N-acetylcysteamine occurs at a limiting rate (1.8 min-1) that is comparable to that estimated for chloropropionyl-CoA-dependent inactivation. However, this enzyme lacks the ability to deprotonate C2 of an acyl group such as the chloropropionyl moiety. Since such a step would be required to generate an acrylyl group from chloropropionyl-S-enzyme, it is likely that a typical affinity labeling process accounts for inactivation of fatty acid synthase by chloropropionyl-CoA. HMG-CoA lyase is also inhibited by S-acrylyl-N-acetylcysteamine. In contrast to the ability of this reagent to serve as a mechanism-based inhibitor of hydroxymethylglutaryl-CoA synthase and an affinity label of fatty acid synthase, it acts as a group-specific reagent in modifying HMG-CoA lyase (kappa 2 = 86.7 M-1 min-1).

Acyl Coenzyme A↗