Biomedical subjects

S Ismail

Publications and source records attributed to S Ismail.

At least 37 records · Page 2Linked to original sources

PubMed1995

Reduction of femoral arterial bleeding post catheterization using percutaneous application of fibrin sealant.

The number of cardiac catheterizations performed yearly is growing with correspondingly increasing amounts of morbidity, complications, and hospital costs. This study suggests that fibrin sealant instillation via an arterial sheath at the completion of femoral catheterization may improve hemostasis. Results using fibrin sealant in 12 unheparinized dogs documented significant reductions (McNemar's exact test) versus control for groin ecchymoses (1 versus 8, P = .008) and radiolabeled hematoma formation (0 versus 7, P = .016). Also swelling was less in the fibrin sealant treated groins when compared to control groins (1 versus 6, P = .125), but failed to reach statistical significance. Results in eight heparinized dogs (activated clotting time 374 +/- 22, mean +/- SEM) revealed a statistically significant reduction in signs of gross bleeding in the fibrin sealant-treated groins (1 versus 8, P = .016). This method may contribute to reduced morbidity, complications, and length of hospitalization. It may also allow for earlier patient mobilization after cardiac catheterization.

Administration, Cutaneous↗

PubMed1995

Paracetamol disposition in Thai patients during and after treatment of falciparum malaria.

Investigations in animals have suggested that conjugation of paracetamol may be reduced in malaria. We have measured plasma concentrations and the urinary excretion of paracetamol and its phase II metabolites in eight Thai patients during uncomplicated falciparum malaria and in convalescence, following a 1000 mg single oral dose. The apparent oral clearance (Malaria, 3.6; Convalescence, 3.9; ml.min-1.kg-1), the elimination half-life (Malaria, 3.8; Convalescence, 3.7 h) and apparent volume of distribution (Malaria, 1.2; Convalescence, 1.2; l.kg-1) of paracetamol were similar during malaria and convalescence. In addition, the urinary excretion of paracetamol and its major phase II metabolites and their formation clearances from paracetamol were not significantly different between the two study phases. These data show that clinical malaria infection has no effect on the conjugation of paracetamol in man.

Acetaminophen↗

PubMed1995

Seasonal prevalence of air-borne pollen and spores in Kuala Lumpur, Malaysia.

Aerosampling using Rotorod samplers was conducted in the Institute for Medical Research, Kuala Lumpur, Malaysia, from December 1991 to November 1993. Samples were collected twice a week between 10.00 hours to 12.00 hours. Rods were stained and examined microscopically. A total of 8 and 20 types of pollens and mold spores were collected, respectively. More mold spores were collected than pollens. Grass pollen constituted more than 40 percent of total pollen counts. Gramineae pollen counts peaked in March and September. The most abundant mold spore was Cladosporium followed by Rust, Nigrospora, Curvularia and Smut. Cladosporium counts peaked in February and August. Rust counts peaked in June and December whereas counts for Nigrospora peaked in February and October. Highest counts of Smut were recorded in March and October. Curvularia counts peaked in January, June and September.

Allergens↗

PubMed1995

Knowledge, attitude and practice on high risk factors pertaining to HIV/AIDS in a rural community.

A cross-sectional study on knowledge, attitude and practice on high risk factors for human immunodeficiency virus (HIV) infection and acquired immunodeficiency syndrome (AIDS) was carried out among rural males of Dembia district, north Gonder Administrative Zone in January 1993. A random sample of 89(92.8%) males were interviewed by six senior medical students. A total of 66(74.2%) people reported to have heard something about AIDS. Eighty (89.9%) males did not know anything about condoms. The most common sources of information on AIDS were close friends, health workers, school teachers and the radio. Favourable attitude was observed. Fifty-four (60.7%) were afraid of getting AIDS; 7.5% had practised extramarital sex in the past three months. Higher knowledge was not associated with high risk behaviour (p > 0.05). Higher knowledge and favourable attitude were strongly correlated, (r = 0.83, 95% CI = 0.76-0.89). Strengthening risk perception, condom promotion and larger or detailed studies were recommended.

Acquired Immunodeficiency Syndrome↗

PubMed1994

A novel peptide inhibitor of adenylyl cyclase (AC). A peptide from type V AC directly inhibits AC catalytic activity.

Peptides derived from various regions of type V adenylyl cyclase (AC) were studied to determine their effect on AC catalytic activity. Out of 10 examined, only one peptide, peptide 2 (Lys425-Cys444), significantly inhibited both basal and stimulated (forskolin or GTP gamma S (guanosine 5'-O-thiotriphosphate)) type V AC catalytic activity overexpressed in CMT cells. The sequence of this peptide was taken from the first cytoplasmic domain of type V AC, which has a high sequence homology to other AC isoforms. Competition studies performed between the peptide and the substrate ATP showed that the inhibition was noncompetitive. Mutation or truncation of the peptide designed to destroy its secondary structure totally negated the inhibitory effect. This peptide also inhibited the catalytic activity of purified types II and V AC, as well as that of various cells, including S49 cyc- cells. Our data indicate that the peptide directly interacts with AC to inhibit catalytic activity; this provides new information regarding regions of the enzyme involved in its catalytic activation.

Adenylyl Cyclase Inhibitors↗

PubMed1994

Dobutamine echocardiography for determining the extent of myocardial salvage after reperfusion. An experimental evaluation.

BACKGROUND: Although dobutamine echocardiography is being increasingly used to determine the presence of viable myocardium in patients who have undergone successful reperfusion therapy, the physiological basis for such a use has not been clearly defined. Because postischemic myocardium has contractile reserve, we hypothesized that the absolute degree of wall thickening induced by dobutamine during reflow would be directly related to the amount of myocardium that has escaped necrosis. METHODS AND RESULTS: Three groups of 12 dogs each were studied at baseline and during 2 to 6 hours of coronary artery occlusion and 15 minutes of reperfusion. In group 1 dogs, which did not receive dobutamine during any of these stages, percent wall thickening at these stages was 32 +/- 6%, -2 +/- 6%, and 5 +/- 6%, respectively, and there was no relation between infarct size and percent wall thickening during reflow (r = .20, P = .51). In group 2 dogs, which received 15 micrograms/kg per minute of dobutamine at all stages, wall thickening at these stages was 40 +/- 8%, 0 +/- 8%, and 19 +/- 10%, respectively, and a good inverse correlation was noted between infarct size and percent wall thickening during reflow (r = -.81, P = .001). In group 3 dogs, in which wall thickening during reflow was measured both before and during infusion of 15 micrograms/kg per minute of dobutamine, it was 5 +/- 8% and 18 +/- 14%, respectively, at these stages. Although the correlation between infarct size and percent wall thickening was poor in the absence of dobutamine (r = .36, P = .26), an excellent inverse correlation was noted between the two in the presence of dobutamine (r = -.93, P < .001). A fair inverse correlation was also noted between infarct size and the absolute change in wall thickening induced by dobutamine (r = -.72, P < .01). Maximal wall thickening was noted at a dobutamine dose of 15 micrograms/kg per minute, and lower doses did not elicit thickening in the presence of larger infarcts despite the presence of viable myocardium. CONCLUSIONS: When myocardial necrosis coexists with post-ischemic myocardial dysfunction and no residual coronary stenosis, the absolute degree of wall thickening during dobutamine can be used to determine the extent of myocardium that has escaped necrosis. The dose of dobutamine needed to elicit maximal thickening of the postischemic myocardium is related to the amount of myocardial necrosis.

Animals↗

PubMed1994

Quantification of myocardial perfusion with myocardial contrast echocardiography during left atrial injection of contrast. Implications for venous injection.

BACKGROUND: The purpose of this study was to determine whether myocardial perfusion can be quantified with myocardial contrast echocardiography using left atrial (LA) injection of contrast. METHODS AND RESULTS: Based on a series of in vitro and in vivo experiments, the optimal dose of sonicated albumin microbubbles injected into the LA for establishing a linear relation between video intensity and blood volume in the anterior myocardium was determined. In 10 open-chest dogs, myocardial blood flow (MBF) was augmented by increasing myocardial blood volume (MBV) with an intravenous infusion of phenylephrine HCl. In the presence of this drug, left anterior descending artery stenosis was produced, followed by release of stenosis, to change MBF within the anterior myocardium. MBV was calculated by dividing radiolabeled microsphere-derived MBF by microbubble transit rate. There was close coupling between MBF and MBV in the anterior myocardium during LA injection of contrast (y = 1.0x-0.03, SEE = 1.07, r = .92, P < .001). An excellent correlation was also noted between background-subtracted peak video intensity and MBV (y = 0.24x + 0.73, SEE = 0.36, r = .88, P < .001). On multivariate analysis, background-subtracted peak video intensity correlated best with MBV. CONCLUSIONS: Myocardial perfusion can be quantified from time-intensity curves derived from the anterior myocardium after LA injection of contrast. Background-subtracted peak video intensity in this situation correlates closely with MBV. When MBV and MBF are closely coupled, such as during inotropic stimulation of the heart, background-subtracted peak video intensity also correlates closely with MBF. Since there are similarities in the models of LA and venous injections, these data indicate that it may be feasible to quantify myocardial perfusion with myocardial contrast echocardiography after venous injection of contrast.

Animals↗

PubMed1994

Effect of malaria infection on the pharmacokinetics of paracetamol in rat.

1. Paracetamol (P; 50 and 300 mg/kg i.v.) was administered to the control and malaria-infected (MI) male Wistar rat in order to assess the effect of MI on the metabolism of paracetamol to its glucuronide (PG) and sulphate (PS) conjugates and their excretion in urine. 2. At a dose of 50 mg/kg, neither total clearance (ClT) (controls, 20.3 +/- 0.5; MI, 19.9 +/- 0.9, ml/min/kg; mean +/- SD, p > 0.05) nor the renal clearance of P (ClR) were affected by MI. Although the formation clearance of PG (Clf PG) was decreased by about 40% (controls, 6.6 +/- 1.1; MI, 3.9 +/- 0.9, ml/min/kg, p < 0.05), the formation clearance of PS (Clf PS) was increased by 30% in the MI rat (controls, 8.8 +/- 0.9; MI, 11.2 +/- 1.7, ml/min/kg, p < 0.05), and therefore Clm (controls, 19.7 +/- 0.5; MI, 19.2 +/- 0.8, ml/min/kg, p > 0.05) was unchanged by MI. 3. At a dose of 300 mg/kg, MI produced a significant decrease in the total clearance of P (ClT) (controls, 16.9 +/- 1.0; MI, 11.9 +/- 0.9, ml/min/kg, p < 0.05), metabolic clearance (Clm) (controls, 15.9 +/- 1.4; MI, 11.3 +/- 0.9, ml/min/kg, p < 0.05) and the formation clearance of PG (Clf PG) (controls, 7.9 +/- 1.3; MI, 4.7 +/- 1.5, ml/min/kg, p < 0.05) without affecting Clf PS and ClR of P. 4. These findings indicate that MI impairs the glucuronidation of paracetamol in rat in vivo at both the low and high doses of P. Increased sulphate formation appeared to compensate for decreased glucuronidation at the lower dose.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetaminophen↗

PubMed1994

Effect of an experimental malaria infection on the metabolism of phenacetin in the rat isolated perfused liver.

1. The effect of infection with the rodent malaria parasite Plasmodium berghei on the metabolism of phenacetin has been investigated in a rat isolated perfused liver preparation. 2. A bolus dose of phenacetin (10 mg) was introduced into the perfusate reservoir of both control (n = 4) and malaria-infected (n = 4) liver preparations, and samples of bile and perfusate were collected (0-4 h) for hplc analysis of phenacetin, paracetamol and its phase II metabolites. 3. Whereas malaria had no effect on the hepatic clearance of phenacetin (control: 0.64 +/- 0.15 versus malaria: 0.66 +/- 0.14 ml min-1), there was a significant reduction in the hepatic clearance of generated paracetamol (control: 1.22 +/- 0.15 versus malaria: 0.41 +/- 0.08 ml min-1) and the total recovery in bile and perfusate of paracetamol glucuronide (control: 1.18 +/- 0.44 versus malaria: 0.29 +/- 0.20 mg). There was no significant change during malaria infection in the total recovery of either phenacetin (control: 1.30 +/- 0.73 versus malaria: 0.79 +/- 0.36 mg) or paracetamol sulphate (control: 0.81 +/- 0.25 versus malaria: 0.74 +/- 0.16 mg),

Acetaminophen↗

PubMed1993

Effect of malaria infection and endotoxin-induced fever on the metabolism of antipyrine and metronidazole in the rat.

Antipyrine and metronidazole were administered as a cocktail to young (4 weeks old) male Wistar rats (N = 12 for each treatment) to investigate the effect of malaria infection due to the rodent parasite Plasmodium berghei and Escherichia coli endotoxin-induced fever on the metabolism of the two compounds in vivo. Control rats received normal saline. Antipyrine and metronidazole clearances were estimated from a single saliva sample while the formation clearances of their metabolites (in malaria-infected and control rats) were estimated from the product of clearance of parent drug and the fraction of the administered dose excreted as metabolites in urine in 24 hr. Rats treated with endotoxin produced no urine during this period. Malaria infection had no effect on clearance of antipyrine or on formation clearance of any of its metabolites. However, the clearance of metronidazole was reduced by approximately 20% compared with controls as a result of decreased formation of hydroxymetronidazole. Fever decreased clearance of both antipyrine and metronidazole by approximately 36% and 23%, respectively. These results demonstrate that both malaria infection and fever can influence P450-dependent drug metabolism and the effects seen appear to be isozyme-selective.

Animals↗

PubMed1993

Identification of Schistosoma haematobium soluble egg antigens that elicit human granuloma formation in vitro.

Schistosoma haematobium soluble egg antigens (SH SEAs) induce intense granulomas in human hosts that often culminate in severe disease. In an attempt to identify the SH SEA fractions that are responsible for pathology, we combined T-cell Western blotting and an in vitro model of granuloma formation. Whole SH SEAs were dotted onto nitrocellulose pieces or were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and electrotransferred onto nitrocellulose paper. Horizontal strips bearing the separated antigens were solubilized in dimethylsulfoxide and precipitated in carbonate/bicarbonate buffer. Antigen-free and antigen-bearing particles were used to stimulate peripheral blood mononuclear cells (PBMCs) obtained from S. haematobium-infected patients and sex- and age-matched healthy controls to form granulomas in vitro. Whole SH SEA-bearing nitrocellulose particles elicited in vitro formation of granulomas by PBMCs from infected donors. The response was similar in sensitivity, specificity, and reproducibility to that evoked by SH SEA-bound polyacrylamide beads. The results obtained in samples form 30 patients and 10 controls tested with SH SEA-separated fractions revealed that SEA bands of 84,000, 63,000, 57,000, 55,000, 40,000, 30,000, and 28,000 Da elicited in vitro granuloma reactions by PBMCs of almost all infected patients. Conversely, separated soluble adult-worm antigens failed to stimulate PBMCs of infected patients to form granulomas. This study is the first to identify the SH SEA fractions that evoke in vitro granuloma formation and represents an initial step toward the development of an anti-urinary schistosomiasis pathology vaccine.

Adolescent↗

PubMed1992

The effect of malaria infection on 3'-azido-3'-deoxythymidine and paracetamol glucuronidation in rat liver microsomes.

The effect of malaria infection on UDP-glucuronosyltransferase (UDPGT) activity was investigated in rat liver microsomes using 3'-azido-3'-deoxythymidine and paracetamol. The Michaelis-Menten parameters, Km and Vmax were calculated and intrinsic clearance values were estimated for normal and infected livers. The results show that malaria infection alters the activity of UDPGT.

Acetaminophen↗

PubMed1992

Maternal mortality in Assiut.

Twenty-nine maternal deaths were identified among 8656 pregnant women residing in Assiut city and three surrounding villages (Upper Egypt). This gives a maternal mortality ratio of 368 per 100,000 live births. Of these maternal deaths 83% were due to direct obstetric causes (hemorrhage, eclampsia, ruptured uterus and sepsis). Logistic regression analysis showed that residence (in villages versus Assiut city), parity (nullipara and grandmultipara) and illiteracy were significantly associated with increased risk of maternal death.

Adult↗

PubMed1992

Metabolic changes during serial squash matches in older men.

We have previously reported dramatic changes in heart rate and blood biochemistry in older men during and shortly after competitive squash. In this study we sought to determine whether these changes are attenuated or exaggerated during tournament matches played in rapid succession. Ten veteran (greater than 45 yrs) players were studied during three competitive matches played over a 36-hr period. Squash was associated with significant changes in heart rate and circulating concentrations of catecholamines, lactate, free fatty acids, and potassium. These changes were of equal magnitude and in some cases tended to be exaggerated during the second and third matches. These data confirm the acute changes in cardiac function and metabolism that occur during competitive squash and suggest that these responses are not down-regulated but may in fact be accentuated during sequential tournament matches.

Aging↗

PubMed1992

Identification of the Schistosoma haematobium soluble egg antigens inducing antibody production and/or T cell proliferation in humans.

Soluble antigens were prepared from Schistosoma haematobium eggs collected from urine of 6-16 year-old children with urinary schistosomiasis. The electrophoretic profile of the soluble egg antigen (SEAH) preparation was almost identical to that (SEAh) obtained from UNDP/World Bank/WHO, Switzerland and prepared from S. haematobium eggs retrieved from intestines of infected hamsters. Reactivity of 50 individual patients with S. haematobium in Western blots led to the identification of the SEA protein bands carrying human B cell epitopes. Some, but not all, of these SEA proteins initiated peripheral blood T lymphocyte proliferation in T cell Western assays. These antigens are probably the ones inducing granulomatous response in vivo, and that are responsible for the immunopathology of the disease.

Adolescent↗

PubMed1991

Safety and efficacy of sonicated albumin microspheres in perfusion and vein graft patency assessments.

This study was designed to identify a concentration of sonicated albumin microspheres that is safe, useful in determining graft patency, and provides an estimate of regional myocardial perfusion. The study included 8 patients between 50 and 72 years of age who were undergoing coronary artery bypass grafting. All patients were hemodynamically stable with left ventricular ejection fractions greater than or equal to 0.35. None had congestive heart failure or myocardial infarction within 4 months prior to the study. All had normal baseline neurologic and renal functions, and none had experienced allergic reactions to blood products or contrast dyes. A standard median sternotomy was performed for exposure of the heart at surgery, and saphenous veins were harvested and used for grafting. Intraoperative epicardial echocardiography (EE), always in the left ventricle short-axis at midpapillary level, was performed before and after grafting to determine regional myocardial wall motion. Sonicated albumin microspheres were prepared and injected into a single vein graft using an 18-gauge needle; 20 x 10(6), 100 x 10(6), and 200 x 10(6) microspheres were injected into the first graft sequentially. All other vein grafts were injected once with the dose that gave optimal contrast enhancement in the initial graft studied. In each patient, a minimum of 3 and maximum of 5 injections were performed, and graft perfusion was studied using EE. Graft flow, blood pressure, and electrocardiographic (ECG) measurements were continuously monitored, with a final EE performed after weaning the patient off cardiopulmonary bypass to assess wall motion. Preliminary results showed that no patient had adverse effects during or after the study and all remained hemodynamically stable.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1991

Efficacy of three pyrethroids against Leptotrombidium fletcheri (Acari: Trombiculidae) infected and noninfected with scrub typhus.

Toxicities of three pyrethroids, d-phenothrin, decamethrin, and permethrin, were evaluated in the laboratory against Leptotrombidium fletcheri (Womersley & Heaslip). The susceptibilities between populations of the species infected and noninfected with scrub typhus were investigated. The three pesticides exhibited different toxicities to the chiggers. D- phenothrin was the most toxic, followed by decamethrin, then permethrin. There were no significant differences between susceptibilities of the infected and noninfected populations. Log-probit regression lines indicated that the species was most sensitive to increasing concentrations of d-phenothrin and least sensitive to permethrin. The results show that the three pesticides are potential candidates for chemical control of L. fletcheri. It may be possible in the future to conduct similar bioassays only with the noninfected population, thus reducing risk of infection to workers conducting the bioassays. Similarly, there may not be a need to separate field-collected chiggers into the two populations before performing the bioassays.

Animals↗

PubMed1991

Lack of evidence for a saturable tetracycline transport system in Staphylococcus aureus.

Previous studies on tetracycline transport into Staphylococcus aureus identified a high-affinity, saturable uptake system for the antibiotic (Km, 4.76 microM) (B.L. Hutchings, Biochim. Biophys. Acta 174:734-738, 1969). However, the earlier results could not be confirmed using conditions that permitted energy-dependent, concentrative uptake of tetracycline. Kinetic artifacts introduced by inappropriate washing procedures may explain the previous results.

Biological Transport, Active↗