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Biomedical subjects

H Osman

Publications and source records attributed to H Osman.

At least 19 recordsLinked to original sources
PubMed1999

Elicitins trap and transfer sterols from micelles, liposomes and plant plasma membranes.

Using elicitins, proteins secreted by some phytopathogenic Oomycetes (Phytophthora) known to be able to transfer sterols between phospholipid vesicles, the transfer of sterols between micelles, liposomes and biological membranes was studied. Firstly, a simple fluorometric method to screen the sterol-carrier capacity of proteins, avoiding the preparation of sterol-containing phospholipidic vesicles, is proposed. The transfer of sterols between DHE micelles (donor) and stigmasterol or cholesterol micelles (acceptor) was directly measured, as the increase in DHE fluorescence signal. The results obtained with this rapid and easy method lead to the same conclusions as those previously reported, using fluorescence polarization of a mixture of donor and acceptor phospholipid vesicles, prepared in the presence of different sterols. Therefore, the micelles method can be useful to screen proteins for their sterol carrier activity. Secondly, elicitins are shown to trap sterols from purified plant plasma membranes and to transfer sterols from micelles to these biological membranes. This property should contribute to understand the molecular mechanism involved in sterol uptake by Phytophthora. It opens new perspectives concerning the role of such proteins in plant-microorganism interactions.

Algal Proteins↗
PubMed1998

Coronary flow and flow reserve in canines using MR phase difference and complex difference processing.

Coronary artery disease continues to be the leading cause of death for adults in the United States. Magnetic resonance imaging (MR) has the potential to dramatically impact the diagnosis of heart disease by noninvasively providing a wide range of anatomic and physiologic information. Previous research has shown that coronary flow, one component of a complete examination, can be accurately measured in the left anterior descending artery in vivo. The current work validates MR flow measurements in canine circumflex arteries using transit time ultrasound as a standard. The circumflex artery experiences greater in-plane motion and is a more stringent test for flow measurement accuracy. This work also compares two methods of processing MR velocity data, phase difference and complex difference techniques, and examines the sources of error present in the animal validation model. Phase difference processing with a 30% magnitude threshold best matched the mean ultrasound flow values (30% PD = 1.04 x US + 1.49, r = 0.94), but it was very sensitive to vessel boundary identification. The complex difference process was less sensitive to vessel boundary identification and correlated well with the transit time ultrasound despite systematic underestimations. The reasons for the discrepancies are shown to stem from a number of possible sources including variability of the ultrasound standard, low signal-to-noise ratios in the MR images, sensitivity of the MR technique to vessel boundary identification, and motion artifacts in the images.

Animals↗
PubMed1997

Geranylgeranyl as well as farnesyl moiety is transferred to Ras p21 overproduced in adrenocortical cells transformed by c-Ha-rasEJ oncogene.

The ras-transformed newborn rat adrenocortical (RTAC) cells were obtained by transfection with the mutated c-Ha-rasEJ oncogene. They are proliferative and tumorigenic cells characterized by expression of the c-Ha-rasEJ oncogene and overexpression of a wild-type ras oncogene. The overproduced Ras p21 was identified here as Ki-Ras p21 by western blotting using a specific anti-Ki-Ras monoclonal antibody. Radioactivity derived from [14C]mevalonolactone was strongly incorporated into Ras p21 overproduced in RTAC cells. RTAC cells pretreated with lovastatin and labeled with either [3H]geranylgeranyl-pyrophosphate or [3H]farnesyl-pyrophosphate incorporated also radioactivity into Ras p21. These results showed that overproduced Ras proteins were geranylgeranylated as well as farnesylated in RTAC cells. These findings suggest that the strategy for inhibiting proliferation of Ki-ras-dependent tumorigenic cells should be directed against not only farnesylation but also geranylgeranylation of Ras p21.

Adrenal Cortex↗
PubMed1997

The safety and efficacy of desflurane.

Desflurane is a new halogenated ether inhalational general anesthetic with low solubility in blood and body tissues. The aim of this study was to assess its anesthetic efficacy in elective surgical procedures, to evaluate its effect on patients' vital signs during maintenance and recovery and to detect the possible side effects (if any) on patients' liver and kidney functions. The study was carried out on thirty adult (ASA I and II) patients scheduled for different surgical procedures. All patients were premedicated with 0.1 mcg kg-1 oral midazolam and induced with 1 mcg kg-1 fentanyl followed by thiopentone sodium 4 mg kg-1 and atracurium 0.5 mg kg-1. The inspired concentration of desflurane was gradually increased until the required depth of anesthesia was reached. The results showed hemodynamic stability under desflurane. It has dose-dependent hypotensive effects with no arrhythmia. It potentiated atracurium, as the total dose needed to produce complete relaxation was 0.36 +/- 1.18 mg kg-1. There was no observable effect on both liver and kidney function given the small number of patients that were included in this study. In the post anesthetic period desflurane showed rapid recovery (3.81 +/- 4.076) and patients' recovery room stay was (17.22 +/- 1.079 min). No postoperative complications were detected.

Adult↗
PubMed1996

Functional, biochemical, and morphological hepatobiliary effects in rats chronically exposed to a steroidal antiandrogen.

Yellow-brown deposits in intrahepatic bile ducts and portal macrophages were observed for male, but not female, Sprague- Dawley rats fed zanoterone, a steroidal antiandrogen, for >=3 months. The lesion did not affect biliary canaliculi and was associated with changes of biliary epithelium, portal chronic inflammation, and bile duct proliferation. Deposit formation was assumed to be related to a gender-related anomaly in bile composition and/or flow. Therefore, the pathogenesis of the lesion was investigated in male, female, and orchiectomized rat. Hepatobiliary structure and function were evaluated after 3 months of treatment and 3 months of reversibility. Drug biliary disposition was evaluated at 3 months. Sulfobromophthalein clearance, bile flow, and plasma concentration and biliary excretion rate of cholesterol were increased at the end of the treatment phase without significant sex-related differences. These effects are consistent with the hepatic enzyme induction potential of the drug, were accompanied by perivenous hepatocellular hypertrophy and increased liver weights, and were no longer observed at the end of the recovery phase. Histomorphologic evidence of cholestasis was observed for most intact and orchiectomized males, the lesion being slightly less pronounced for the latter. Deposits were present at the end of the recovery phase, but were confined to macrophages in all but one case. The lesion differed from a protoporphyria, or precipitates of bile pigments, cholesterol, or proteins. The drug was extensively metabolized with major gender-related differences. Glucuronides of a 16- hydroxy- and another unidentified metabolite were the major metabolites found in bile of males, while a 15-hydroxy-glucuronide was the major metabolite for females. The concentration and biliary excretion of the 16-hydroxy- glucuronide markedly increased after chronic exposure. A possible explanation for pigment deposition in males is that the drug is converted to a metabolite(s) which is excreted at a rate beyond the solubilization potential of bile and, therefore, precipitates in bile ducts.

Androgen Antagonists↗
PubMed1995

Antimicrobial activity of Cassia alata from Malaysia.

Ethanolic extract of Cassia alata leaves was investigated for its antimicrobial activities on several microorganisms including bacteria, yeast, dermatophytic fungi and non-dermatophytic fungi. In vitro, the extract exhibited high activity against various species of dermatophytic fungi but low activity against non-dermatophytic fungi. However, bacterial and yeast species showed resistance against in vitro treatment with the extract. The minimum inhibitory concentration (MIC) values of the extract revealed that Trichophyton mentagorphytes var. interdigitale, Trichophyton mentagrophytes var. mentagorophytes, Trichophyton rubrum and Microsporum gypseum had the MIC of 125 mg/ml, whereas Microsporum canis had the MIC of 62.5 mg/ml. The inhibition can be observed on the macroconidia of Microsporum gypseum which resulted in structural degeneration beyond repair. The mechanism of inhibition can be related to the cell leakage as observed by irregular, wrinkle shape and loss in rigidity of the macroconidia.

Anti-Bacterial Agents↗
PubMed1995

Ranitidine versus cimetidine prior to emergency obstetric anesthesia.

Twenty parturients in labour received emergency obstetric anesthesia were randomly divided into two equal groups. Group "R" received 150 mg oral ranitidine tablet on admission, followed by 50 mg infusion in 250 ml dextrose 5% over 30 minutes prior to anesthetic induction. Group "Ce" received 400 mg cimetidine oral tablet and 100 mg infusion in 250 ml dextrose 5% over 30 minutes. Ten parturients were considered as control. Ranitidine significantly reduced the maternal gastric volume with marked alkalinization of gastric pH. No significant changes were detected in the height, frequency or amplitude of uterine contraction or neonatal assessment.

Anesthesia, Obstetrical↗
PubMed1995

Development of photo-sensing bulge ductility tester.

The ductility of thin films is normally evaluated by conducting the bulge testing. However, the accuracy of the conventional type of mechanical bulge ductility testing unit is poor in determining the actual elongation. In this development, a photo-sensitive device is provided in the detecting portion to accurately measure the elongation. The sensitivity depends on the type of the materials tested. A Pyrex glass ball is utilized as a punching ball to provide equally distributed light. Pushing of the Pyrex glass is activated by a hydraulic media to control the punching velocity. Accuracy and reproducibility were primarily checked with copper thin foil deposited on polyimide substrates. Two types of dental articulating papers (paper-based and plastic-based) were tested. It was suggested that an appropriate selection of articulating paper to mark the occlusal interferences is essential for precise determination of occlusal harmony.

Dental Materials↗
PubMed1994

Patient self-determination and the artificial prolongation of life.

Ethical dilemmas are inherent in health care decision making. The Patient Self-Determination Act of 1990 provides health care facilities with guidelines to address patients' advance directives. Family members who are charged with the responsibility to implement their loved ones' wishes often feel emotional conflicts because of the many difficulties that arise from making life and death decisions for another person. The PRACTICE model discussed in this article allows health care practitioners to think about ethical issues in a structured and systematic way. Social workers have a vital role to play in facilitating the implementation of patients' advance directives by working with the patient in creating clear and accurate directives, by supporting the family in allowing these directives to be carried out, and by working with the treatment team to resolve ethical dilemmas.

Advance Directives↗
PubMed1994

[Vulvar involvement in Crohn disease].

INTRODUCTION: There are many skin manifestations of Crohn's disease including specific lesions occurring late after digestive signs. These manifestations are also termed metastatic and are rarely located on the vulva. CASE REPORT: We observed a metastatic localization in the vulva of Crohn's disease in a 34-year-old woman with predominantly rectosigmoid disease. The right labia major was greatly enlarged with oedema involving the inguinal cural area. Pustulization and erosive lesions were seen. The course of these lesions was independent of the colonic disease and responded temporarily only to a triple drug combination of metronidazol, prednisolone and minocyclin. CONCLUSION: This case emphasizes the frequency of colonic or rectal manifestations associated with vulval involvement in Crohn's disease. The metastatic lesions follow a course independent of the digestive disease raising therapeutic problems in this localization.

Adult↗
PubMed1978

The nephrotic syndrome in the Sudan with special reference to schistosomal nephropathy. A preliminary morphological study.

The morphology of 68 renal biopsies from the Sudan is analysed. Schistosomal infection was more common among the nephrotic patients than in the average population (32% against less than 1%). In the schistosomal group the high incidence of focal sclerosing glomerulonephritis (28%) and of secondary amyloidosis (38%) was remarkable. The history is described of a boy in whom repeated biopsies showed the decrease of glomerular amyloid depositions accompanied by mesangial cell proliferation following treatment for schistosomiasis.

Adolescent↗