Dr Mohammed Mahmoud Youssif

Spontaneous Raman/Rayleigh measurements have been carried out in turbulent partially premixed flames of nitrogen-diluted methane near extinction. The flames are created in a reverse flow reactor (RFR) and are stabilized by means of a recirculation zone. The flames are stretched by reducing the residence time of the flow within the reactor. The mean profiles, scatter plots, and conditional pdfs are used to study the flame structure in the present investigation. The detailed structure studies have been carried out in two shear layers, where the stretch rates are highest. The data presented in this article are for two flames close to extinction at low residence times (3.6 and 5.1 ms). The flame structure at both shear layers shows quite significant chemical kinetic effects on approaching extinction. These effects reduce the products concentration and temperature and increase the reactants. Also, these effects increase the CO concentration. A substantial decrease in the reactedness of the reactive scalars has also been found at both shear layers on approaching extinction. The flame structure shows broad distribution between the equilibrium and frozen limits with no obvious bimodality. From the conditional pdfs, the reactedness decreases around stoichiometric and increases at the lean side of the stoichiometric. © 1991.

Spontaneous Raman/Rayleigh measurements have been carried out in turbulent partially premixed flames of nitrogen-diluted methane near extinction. The flames are created in a reverse flow reactor (RFR) and are stabilized by means of a recirculation zone. The flames are stretched by reducing the residence time of the flow within the reactor. The mean profiles, scatter plots, and conditional pdfs are used to study the flame structure in the present investigation. The detailed structure studies have been carried out in two shear layers, where the stretch rates are highest. The data presented in this article are for two flames close to extinction at low residence times (3.6 and 5.1 ms). The flame structure at both shear layers shows quite significant chemical kinetic effects on approaching extinction. These effects reduce the products concentration and temperature and increase the reactants. Also, these effects increase the CO concentration. A substantial decrease in the reactedness of the reactive scalars has also been found at both shear layers on approaching extinction. The flame structure shows broad distribution between the equilibrium and frozen limits with no obvious bimodality. From the conditional pdfs, the reactedness decreases around stoichiometric and increases at the lean side of the stoichiometric. © 1991.

Fifty-one patients with CCT verified cerebral infarction were submitted to serum and CSF radioimmunoassay of FSH, LH, estradiol (E2), progesterone, testosterone, cortisol and T4. The results were compared to those of 82 matched controls. Our findings suggest that (1) high serum E2 is a risk factor of stroke in males; (2) low serum T4 is a risk factor in males; (3) serum testosterone is reduced in acute stroke in males confirming that it is stress sensitive; (4) serum LH was higher in hypertensive thrombotic males when compared to normotensive ones, and (5) FSH, LH, E2 and T4 are undetectable in CSF of patients and controls.

The influence of the prenatal and postnatal maternal environment on stroke susceptibility was evaluated by reciprocally crossing the spontaneously hypertensive (SHR) and the Dahl salt-sensitive (SS/Jr) inbred rat strains to produce reciprocal F1 hybrids that were nurtured, respectively, during prenatal and postnatal life by SHR or SS/Jr mothers. Following placement on a high-salt diet containing 8% NaCl at 35 days of age, F1 rats reared by SHR mothers had shorter survival times and were more likely to die with cerebral hemorrhage than F1s reared by SS/Jrs. Across reciprocal F1 female groups, enhanced susceptibility to stroke was associated with greater elevations of systolic blood pressure, but this association was not seen across reciprocal F1 male groups. There was also an association between blood pressure and stroke within each F1/gender subgroup: Rats eventually suffering strokes developed higher blood pressure after placement on the high-salt diet than rats that did not suffer stroke. Lower day 35 body weights (before exposure to the high-salt diet) were associated with greater likelihood of stroke both across the reciprocal F1 groups, and within three of the four F1/gender subgroups. The differences in stroke susceptibility between the reciprocal F1 groupings may be due to systematic differences in the prenatal and/or postnatal environments of SHR and SS/Jr mothers and may be mediated by variations in the nutritive capacity of the two inbred mothers.

Five clinically health goats were injected with sulfadimethoxine and sulfadimethyloxazole in a single dose of 100 mg/kg b. wt. by intravenous route. Highest concentration levels of sulfadimethoxine and sulfadimethyloxazole in rumen were detected 1 hour following intravenous injection, then the concentration for both compounds declined at 12 and 8 hours post administration, respectively. In addition, both types of sulfonamide completely disappeared in ruminal fluid samples taken after 24 and 12 hours, respectively. The rate of acetylation for sulfadimethoxine and sulfadimethyloxazole were nearly similar and occurred to a high extent in ruminal fluid (22.95 and 23.72%, respectively). On the other hand, both tested drugs increased significantly the ruminal gas production from the first to eight hours after i.v. injection in goats. Changes in the serum enzyme activities (SGOT, SGPT and alkaline phosphatase) observed with sulfadimethoxine and sulfadimethyloxazole, and represented by a significant decrease in the activity of SGOT and SGPT level, alkaline phosphatase 4 hours sulfadimethoxine and in GOT/GPT ratio 24 and 48 hours after i.v. injection, respectively. The creatinine clearance was significantly decreased after 4 hours following the i.v. administration of sulfadimethoxine and sulfadimethyloxazole in goats.

A major constraint for expanding biotechnology in developing countries is the tack of appropriate microbial strains and microbial genetic resources. The recently established Microbial Strain Data Network (MSDN) offers the opportunity of, at least partially, llfting these constraints, since even a small institutional culture collection with limited to moderate facilities can act as an active two-way node in the network. We describe the establlshment of a nucleus for culture collection in the biotechnology laboratory, selecting methodologies as compatible as possible with those of the Cairo MIRCEN, and in assembling a database on the collected strains using a format that lends itself to participation in the MSDN.

Cefotaxime was administered to goats intravenously, intramuscularly and subcutaneously to determine blood and urine concentration, kinetic behaviour and bioavailability. Following a single intravenous injection, the blood concentration-time curve indicated a two compartment open model, with an elimination half-life value (t1/2 beta) of 22.38 +/- 0.41 minutes. Both intramuscular and subcutaneous routes showed slower values, that is, 38.64 and 69.58 minutes. The apparent volume of distribution of cefotaxime in goats was less than 1 litre kg-1 and suggested a lower distribution in tissues than in blood. After intramuscular and subcutaneous injections peak plasma cefotaxime concentrations were 77.8 +/- 1.7 and 44.0 +/- 0.8 micrograms ml-1 at 29.6 and 40.4 minutes, respectively. The average bioavailability of cefotaxime given by intramuscular and subcutaneous injection was 1.08 and 1.25 times the intravenous availability, respectively. The cefotaxime concentration remained in urine 24 hours longer after subcutaneous injection than after intramuscular administration.

The disposition phenazone (antipyrine) was used to study the effect of Schistosoma mansoni infection on the activity of drug metabolizing enzymes in mice. Plasma elimination rate constant (Ke), elimination half-life (t1/2e), clearance (CL) and apparent volume of distribution (Vd) were estimated 8 and 12 weeks after infection of mice with 80 S. mansoni cercariae. Liver and kidney function tests were performed simultaneously. Infection increased the levels of glutamic oxalacetic transaminase (GOT), glutamic pyruvic transaminase (GPT), lactic dehydrogenase (LDH), alkaline phosphatase (AP) and total proteins 8 and 12 weeks post infection. At the same time a decrease was recorded in the total cholesterol level. Moreover infection with S. mansoni produced a decrease in phenazone clearance with an increase in the area under the curve (AUC) of the drug 8 and 12 weeks post infection. Elimination half-lives were 57.92 +/- 14.10 and 72.72 +/- 4.14 min 8 and 12 weeks after infection, respectively, compared to 19.29 +/- 3.30 and 26.14 +/- 5.31 min in corresponding controls. No statistically significant change was recorded in the volume of distribution of phenazone in the groups studied. In addition no significant correlation was found between parameters of phenazone disposition and the enzyme levels studied 8 and 12 weeks after infection.

The disposition phenazone (antipyrine) was used to study the effect of Schistosoma mansoni infection on the activity of drug metabolizing enzymes in mice. Plasma elimination rate constant (Ke), elimination half-life (t1/2e), clearance (CL) and apparent volume of distribution (Vd) were estimated 8 and 12 weeks after infection of mice with 80 S. mansoni cercariae. Liver and kidney function tests were performed simultaneously. Infection increased the levels of glutamic oxalacetic transaminase (GOT), glutamic pyruvic transaminase (GPT), lactic dehydrogenase (LDH), alkaline phosphatase (AP) and total proteins 8 and 12 weeks post infection. At the same time a decrease was recorded in the total cholesterol level. Moreover infection with S. mansoni produced a decrease in phenazone clearance with an increase in the area under the curve (AUC) of the drug 8 and 12 weeks post infection. Elimination half-lives were 57.92 +/- 14.10 and 72.72 +/- 4.14 min 8 and 12 weeks after infection, respectively, compared to 19.29 +/- 3.30 and 26.14 +/- 5.31 min in corresponding controls. No statistically significant change was recorded in the volume of distribution of phenazone in the groups studied. In addition no significant correlation was found between parameters of phenazone disposition and the enzyme levels studied 8 and 12 weeks after infection.