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Biomedical subjects

A M el-Sayed

Publications and source records attributed to A M el-Sayed.

11 recordsLinked to original sources
PubMed1994

Serum-hydroxyapatite interaction in vitro.

In a project to develop hydroxyapatites for bone replacement, biological and synthetic types were prepared at 600 degrees C, ground to 300-600 microns and immersed in a pooled human serum for periods up to 1 month at 4 degrees C to assess material interaction. It was found that the levels of calcium in the serum were reduced at 6 h immersion, followed by an increase to reach maximum at 48 h and then stability up to 1 month. Phosphorus levels showed the opposite behaviour. Both apatites showed similar trends, although higher values were recorded for the synthetic type, suggesting higher activity. Infrared spectral analysis complemented the biochemical values, where the optical densities (O.D.) of phosphate groups were reduced, reflecting the increased phosphorus in serum and denoting leaching. Also, O.D. values of both CO3(2-) and OH- groups were reduced at 10 h, then returned to original levels. Scanning electron microscopy revealed a spongy appearance parallel with reduced O.D. and higher levels of serum Ca2+. At longer periods (48 h) the concentric needles of hydroxyapatite are clearly shown to be deposited on biological apatite. Differences in responses were attributed to their original crystalline structure assessed by X-ray diffraction analysis, as well as pore analysis using a mercury porosimeter.

Bone Resorption↗
PubMed1993

Evaluation of the effect of formulation type of povidone/iodine preparations on infection and wound healing.

Different povidone/iodine (PI) dosage forms (e.g. solution, ointment, gel) in various PI concentrations and percentage of water were prepared. The efficacy of these formulations was assessed in vitro bacteriologically and clinically in large number of human and animal subjects. Comparison of their effect with those of other agents in some cases was made. The results obtained indicated that the antibacterial activity of PI in different formulation types was in the order: aqueous solution > water soluble ointment base containing 20% (w/w) water > aqueous gel base > water soluble ointment base containing 10% (w/w) water > water soluble ointment base > oleaginous base. PI is more efficient when comparing it with some conventional antiseptics, used clinically, and enhances wound healing process.

Animals↗
PubMed1993

Dissociation constant of chlordiazepoxide in montmorillonite suspension and its pharmaceutical application for a controlled-release dosage form.

The changes in the distribution of the ionic species of a drug due to interactions with a clay surface may have important consequences in drug therapy. The binding of chlordiazepoxide (CDO) into montmorillonite clay, veegum: HV (V), surface was studied under several pH conditions. In vitro drug release behaviour from CDO-V products was investigated. Changes in the partial molar free energy of the ionic species of CDO, delta Gi (i = CDO, CDOH+) as a result of interaction with V were determined by using differential absorbance spectroscopic techniques at 260 and 310 nm. The stronger interaction between the negatively charged clay surface and the protonated species (CDOH+) relative to the parent compound is responsible for the apparent displacement of its pKa value in V suspensions from 4.64 to 5.67. In vitro drug release behaviour from CDO-V product to the simulated gastrointestinal fluids showed a controlled pattern. The in vivo results indicated a prolonged drug effect after the oral administration of drug-clay preparation.

Bentonite↗
PubMed1992

Scalp aplasia cutis congenita: closure by the L-shaped flap.

A case of aplasia cutis congenita of the scalp with bony defect in a newborn treated by early excision and reconstruction is presented. A recently described versatile minor flap is employed to cover the resultant defect. The advantages of early surgical repair and the flap are highlighted.

Ectodermal Dysplasia↗
PubMed1992

Availability of phenindione-beta-cyclodextrin inclusion complex.

The inclusion complexation was occurred between beta-cyclodextrin (beta-CD) and phenindione (1) in aqueous solution. The complex formation was proved by solubility, dissolution and permeation study. The inclusion complex was prepared and its physicochemical properties was studied. 1 was combined with beta-CD in 1:1 molar ratio. Using the solubility data, the value of apparent stability constant obtained of 1/beta-CD complex was 492.7. The dissolution rate of 1 was increased in presence of beta-CD. The permeability coefficients of 1 were 7.86 x 10(-3), 4.76 x 10(-3) and 5.0 x 10(-3), corresponding to pure drug, its physical mixture with beta-CD and the inclusion complex, respectively. The presence of human albumin generally decreased the permeability coefficient of the drug. The reduction (79.5%) was found to be nearly equal in case of either pure 1 or its complex with beta-CD. Administration of 1 or its inclusion complex with beta-CD to rabbits increase prothrombin times, the effect was more pronounced in the complex form of drug than free one.

Animals↗
PubMed1990

Reliability of death certificate diagnoses.

Consistency between death certificates and clinical records from 5 general hospitals in Kuwait was studied for 470 deaths with the following underlying or associated causes: hypertensive (HYP), ischaemic heart diseases (IHD), cerebrovascular diseases (CVD) and diabetes mellitus (DM). Direct causes were not considered since they are of little interest analytically. Only deaths with definite or most probable ascertainment were included. One cardiologist, who was provided with the WHO criteria and relevant documents on death certification, independently reviewed the records. To test the reviewer's bias and the reliability of his judgement, an adjudication process was effected by having one senior cardiologist re-review a random subsample of 140 records. The two reviewers showed good agreement. Specific diagnoses criteria for deciding the underlying cause of death in multiple morbid conditions by the reviewer were followed. Due to possible reviewer bias, we aimed at measuring the difference between initial certifiers and the reviewer rather than measuring the diagnostic accuracy of initial certifiers in reference to the reviewer. The agreement index kappa showed poor agreement between original and revised certificates. The original certificates under-estimated CVD as an underlying cause of death by 69.2%, DM by 60%, IHD by 33.5% and HYP by 31.8% in our sample. Associated causes were also consistently under-estimated by initial certifiers as compared with the reviewer. This bias calls for basing mortality statistics in Kuwait on hospital death committees' reports rather than on initial certifier death certificates, use of multiple-causes of death instead of one underlying cause and adequate training of the medical profession on the value and process of death certification.

Adolescent↗
PubMed1990

Interaction of some benzothiadiazine diuretics with beta-cyclodextrin.

The interaction of three structurally related benzothiadiazine diuretics, viz., hydroflumethiazide, bendrofluazide and cyclopenthiazide wit beta-cyclodextrin was investigated. The study aimed at enhancing the solubility of these poorly soluble drugs via inclusion complexation with beta-cyclodextrin, Solubility measurements revealed that complexes were formed between each of three drugs and beta-cyclodextrin, The complexes were found to have 1:1 stoichiometric ratios and stability constants of 165.4, 55.7 and 27.9 M-1 for cyclopenthiazide, bendrofluazide and hydroflumethiazide, respectively. UV spectrophotometric analysis of the formed complexes agreed with the solubility results. The variation in the extent of binding between each of the three drugs and beta-cyclodextrin was attributed to their variation in molecular volume, partition coefficient and electrostatic properties of the binding sites.

Bendroflumethiazide↗
PubMed1987

The use of psychoactive substances by female Egyptian university students, compared with their male colleagues on selected items.

A standardized questionnaire, with satisfactory retake item reliabilities and well established validities, was administered to a representative sample of female university students (N = 2366), drawn from Cairo and Ein-Shams Universities, both located in Greater Cairo. Results, relevant to demographic and drug related items, are presented. Where meaningful, comparisons are made with previously published corresponding data obtained on male university students. Among the interesting findings are the following: Female students, compared with males, had better educated parents with jobs higher on social prestige hierarchy. But more boys than girls had personal sources of income and, relatively, big amounts of pocket money. Very few girls smoked cigarettes and used natural narcotics. Tranquilizers and hypnotics were taken by, almost, equal percentages of both sexes. But stimulants were consumed by more boys. Girls did not start experimentation with narcotics before the age of 16, whereas boys began such experimentation before reaching 12 years of age. Girls tried alcohol much more than they experimented with any other psychoactive substance. Among girls as well as boys we found a measurable trend for users to be more exposed than nonusers to what we call 'drug culture'. In the case of girls, close relatives have more weight than personal friends as sources of information about drugs. For boys, it is the opposite. Similarities as well as disparities were discussed and implications were emphasized.

Adolescent↗
PubMedDate not supplied

Synthesis of some new biologically-active coumarin derivatives.

Coumarin and 6-nitrocoumarin hydrazones (2a,b), respectively, were prepared via the reaction of 2-thiocoumarin (1a,b) derivatives with hydrazine hydrate. The hydrazones were used as key intermediates for the preparation of some benzopyrano[2,3-c]pyrazoles (21-24) through the reaction of different acyl halides and subsequent cyclization in N,N-dimethylaniline. Benzopyrano[2,3-c]pyrazole-3-thione (25a,b) was prepared by the reaction of 1a with CS2 on which some alkylation, acylation and Mannich reactions were studied. Alternative procedures, other reactions and biological activity of some new compounds were given.

Animals↗