Biomedical subjects

S Khatib

Publications and source records attributed to S Khatib.

7 recordsLinked to original sources

PubMed2002

A novel compound JPM8: in vivo penile activity promotion in rats, effect on the relaxation and cGMP/cAMP accumulation in isolated rabbit corpora cavernosa.

JPM8 is a novel sildenafil-like PDE5 inhibitor. Its efficacy was tested in vivo by the oral administration of drugs to a rat model and recording penile activity changes. Effect on the relaxation of the rabbit cavernosa was tested in vitro using an organ bath were drugs are added to the tissue media and relaxation was recorded using a transducer connected to a chart recorder. The accumulation of cGMP and cAMP was measured by incubation of cavernosa strips and then extracting the produced cGMP and cAMP in the incubation mixture, then quantitating it using ELISA. JPM8 showed increased and promoted sexual and penile activity in rats in a similar but slightly higher trend than the positive control sildenafil. JPM8 was more efficient in relaxing the rabbit corpora cavernosa than sildenafil. The cGMP and cAMP accumulation showed a similar trend for both drugs. We concluded that JPM8 was very effective in promoting sexual activity in rats, relaxing the corpora cavernosa and promoting cGMP accumulation in rabbits.

3',5'-Cyclic-GMP Phosphodiesterases↗

PubMed1995

Coagulase-negative staphylococci in multiple blood cultures: strain relatedness and determinants of same-strain bacteremia.

The frequency of strain relatedness was determined among randomly selected patients with coagulase-negative staphylococcal infections as determined in multiple blood cultures by plasmid typing, determination of species, and antibiotyping. Strain relatedness was demonstrated in 21 of 47 episodes of bacteremia (44.7%) among 34 patients, with a similar percentage among patients with two or one positive blood culture in 24 h (14 of 30 [46.7%] versus 7 of 17 [41.2%], respectively). Same-strain bacteremia was more frequent in cases of infection among patients with a corresponding fever (15 of 21 [71.4%]), among patients infected with organisms from an identifiable source (7 of 9 [77.8%]) and with non-Staphylococcus epidermidis species (9 of 11 [81.8%]), and among patients with nosocomially acquired infections (18 of 36 [50%]). Comparing episodes with or without strain relatedness, no difference was noted in the time to growth (2.1 +/- 1.4 versus 1.9 +/- 0.9 days, respectively), in bacterial growth in two culture bottles (5 of 14 [35.7%] versus 8 of 24 [33.3%], respectively), and in the presence of additional negative blood cultures (9 of 21 [42.9%] versus 11 of 26 [42.3%], respectively). The antibiotypes of all related strains and 7 of 44 (15.9%) unrelated pairs were identical. These findings demonstrate that coagulase-negative staphylococci from multiple blood cultures are frequently unrelated, suggesting a high prevalence of contamination. In the absence of precise measures for demonstrating strain relatedness, the combination of a clinical assessment with antibiotype determination appears to be a suitable alternative.

Adolescent↗

PubMed1995

Effects of propofol and thiopentone on picrotoxin convulsive threshold in the rabbit.

The purpose of the present study was to examine the effect of intravenous administration of propofol and thiopentone on picrotoxin-induced seizures using the picrotoxin convulsive threshold test in the rabbit. Neither propofol nor thiopentone at a dose of 1.25 mg/kg had any significant effect on picrotoxin seizure threshold. However, at higher doses (2.5, 5, 10 mg/kg) both propofol and thiopentone produced a significant and dose-dependent increase in the picrotoxin convulsive threshold. These findings suggest that propofol is an effective anticonvulsant against picrotoxin-induced seizures in the rabbit.

Animals↗

PubMed1993

Thyroid function in children with beta-thalassemia major in north Jordan.

Basal thyroid function was assessed by serum thyroxine, tri-iodothyronine and thyroid-stimulating hormone levels in 90 patients 2-10 years old with beta-thalassaemia major. Based on measured serum ferritin levels, patients were classified into two groups: group (I) which included 63 patients with ferritin concentrations ranging from 300 to 7000 ng/ml (mild iron overload) and group (II) which included 27 patients with ferritin concentrations higher than 7000 ng/ml (severe iron overload). The results of thyroid function in both groups were compared with those of 50 control subjects. In group (I), the mean concentrations of all measured hormones were not significantly different from those of the controls. In group (II), the mean concentrations of thyroxine and tri-iodothyronine decreased by 29 and 35 per cent (P < 0.05), respectively, and the mean concentration of thyroid-stimulating hormone showed a 2.6-fold increase (P < 0.01) in comparison with those of the controls. The data clearly demonstrate the occurrence of impaired thyroid function and its possible association with iron overload in a considerable proportion of transfusion-dependent beta-thalassaemic patients.

Case-Control Studies↗

PubMed1990

Effects of glyburide on ischemia-induced changes in extracellular potassium and local myocardial activation: a potential new approach to the management of ischemia-induced malignant ventricular arrhythmias.

The increase in extracellular potassium [K+]o levels during the early phase of myocardial ischemia may result in part from activation of adenosine triphosphate-sensitive K+ channels. Glyburide, a second-generation hypoglycemic sulfonylurea, is a potent blocker of these channels. We studied the effects of glyburide on [K+]o and on intramyocardial conduction delay during a 10-minute occlusion of the left anterior descending artery in the dog. K(+)-sensitive electrodes and bipolar plunge electrodes were introduced to record, respectively, [K+]o and local electrograms from close sites in midmyocardial regions in normal, border, and ischemic zones. Recordings were obtained before (control ischemia [CI]) and 20 minutes after intravenous administration of 0.15 mg/kg of glyburide (glyburide plus ischemia [G + I]). During G + I the extent of the increase in [K+]o was less compared to that during CI, and the difference was statistically significant during the first 7 minutes of ischemia in the ischemic zone and during the first 4 minutes of ischemia in the border zone. On the other hand, the degree of local intramyocardial conduction delay was significantly reduced during G + I compared to CI during the entire 10 minutes of ischemia in both the ischemic and border zones. In summary, our results have shown that glyburide significantly reduced the rise of [K+]o and intramyocardial delay during the early phase of acute ischemia and could thus attenuate the electrophysiologic consequences of ischemia that underlie the initial phase of malignant tachyarrhythmias. Although the effects of glyburide may result in part from a direct action of the drug on cardiac adenosine triphosphate-sensitive K+ channels, other metabolic antiischemic effects cannot be ruled out.

Animals↗

PubMed1985

Determination of polycyclic aromatic hydrocarbons in environmental samples by high performance thin-layer chromatography and fluorescence scanning densitometry.

High performance thin-layer chromatography (HPTLC) with fluorescence scanning densitometry was used for the quantitative determination of polycyclic aromatic hydrocarbons in the soluble organic fraction of air particulate samples. A method using normalized emission response ratios was developed to determine sample identity and to test for peak homogeneity. To preserve the high sample throughput of HPTLC, the two-point calibration method was used for quantitation. The principal advantages of HPTLC as a screening technique for environmental samples are its low cost, methodological simplicity, high sample throughput, and the ability to analyze crude samples with a minimum amount of sample cleanup.

Air Pollutants, Occupational↗

PubMed1984

Comparison of methods for separating polycyclic aromatic hydrocarbons by high-performance thin-layer chromatography.

A comparison is made of different stationary phases (silica gel, cellulose, acetylated cellulose, and 3-aminopropyl-, ethyl-, octyl-, octadecyl-, and diphenylsilanized silica gel), mobile phases, and development techniques (conventional, continuous, and multiple) for the separation of environmentally important polycyclic aromatic hydrocarbons by high-performance thin-layer chromatography. Reversed-phase separations using octadecylsilanized silica gel and methanol-water or methanol-water-based ternary solvent systems were found to give the best separations. A new development technique, multiple development with application of the mobile phase further up the plate at each successive development, provided superior resolution of the polycyclic aromatic hydrocarbons compared with conventional multiple development.

Cellulose↗