Biomedical subjects

S Rizk

Publications and source records attributed to S Rizk.

23 records · Page 2Linked to original sources

PubMed1986

The role of magnetic resonance imaging techniques in the evaluation of orbital and ocular disease.

Technical developments have resulted in a great improvement in the quality of magnetic resonance imaging (MRI) of the orbit. With surface coil data acquisition spatial resolution of less than a millimetre can now be achieved, and contrast discrimination is such that the cortex and nucleus of the lens can be distinguished. The application of MRI to the diagnosis of orbital and ocular pathology was studied in a group of 51 patients with a wide range of pathology. Advantages of MRI over computed tomography (CT) included the avoidance of ionising radiation, the direct multiplanar facility and the use of flow-dependent sequences to identify pathological vessels without the need for contrast medium; although CT was superior in showing bone detail. Only a limited discrimination between different tumour types is possible by assessment of their MRI characteristics. Research is currently being directed towards achieving thinner slices, shorter data acquisition times and removal of the high signal from retrobulbar fat.

Adenoma↗

PubMed1977

Effect of repeated doses of ATP on serum protein pattern and fat content of the liver in experimental diabetes.

A comparison of serum protein fractions (electrophoretic separation) between control and mild alloxan-diabetic rats examined 10 days after alloxan indicates a decrease in total protein, a decrease in percentage albumin accompanied by a decrease in A/G ratio. In severe diabetic rats examined 48 hours after the administration of alloxan, there were no changes in total protein or in serum-protein fractions. The changes in the serum protein and serum albumin in mild diabetic cases are not the result of the degree of diabetes only. But they are rather explained by the longer time interval of the uncontrolled diabetic state. ATP administered to mild diabetic rats producing the following changes: two injections of 5 mg per rat exhibit a lowering effect on the blood glucose, with a decrease in liver fat. ATP resulted also in a significant increase in serum albumin and a decrease in beta-globulin with a consequent increase in the A/G ratio. Comparison of the different protein fractions of male and female control rats did not show any significant difference. ATP administered to control animals did not alter the normal electrophoretic pattern.

Adenosine Triphosphate↗

PubMedDate not supplied

The pharmacokinetics of equoral versus neoral in stable renal transplant patients: a multinational multicenter study.

We studied the pharmacokinetics (PKs) of the new generic cyclosporine formulation, Equoral capsules, after the switch from original formulation Neoral capsules in stable renal transplant patients. The study was carried out in accordance with the basic principles defined in the US 21 CFR Part 312.20 and the principles of the Declaration of Helsinki. The study included clinically stable first renal transplant patients maintained on cyclosporine with no rejection episode during the past 6 months. Hematology, biochemistry, and urine chemistry were determined on day 7, and day 21. The patients were all switched to Neoral (lot number 416MFD0601) on day 0 when the first sparse sampling PK was performed. On day 14 a 12-hour PK profile included predose, 30 minutes; 1 hour; 1 hour 30 minutes; 2 hours; 3 hours; 4 hours; 5 hours; 6 hours; 8 hours; 10-hours and 12-hour samples. Cyclosporine levels were determined using a CYA kit (Abbott TDx). On day 15 the patients were switched from Neoral capsules to Equoral capsules (lot 5T111014) at an equivalent dosage (mg/mg). The second sparse sampling PK was performed on day 21 and a 12-hour PK was performed on day 28. On the morning of day 29 patients were switched from Equoral capsules to Neoral capsules at an equivalent dosage (mg/mg). Additional concentrations were measured on days -7, 18, and 35. Safety parameters were monitored at each visit. The pharmacokinetics of both formulations were equivalent. The mean AUC for Neoral and Equoral was 2856 and 2892, respectively. The ratios of LSM and the 90% confidence intervals for the in-transformed parameters (AUC o-t, AUC inf, and Cmax) of Equoral and Neoral SGC were 98% and 95%, respectively, suggesting that Equoral and Neoral SGC are bioequivalent.

Area Under Curve↗

PubMedDate not supplied

The role of generics in transplantation: TM-MMF versus Cellcept in healthy volunteers.

Because several studies having revealed a relation between early graft rejection and long-term graft survival, potential benefits have been attributed to MMF. The cost of the drug is, however, prohibitive, which renders its long-term use in countries with limited income. We thus compared the pharmacokinetic profiles of a new MMF generic formulation (MM-Cept developed by Ivax CR) with those of Cellcept (Hoffman La Roche) in healthy volunteers. This open label, balanced randomized, two-treatment, two-period, two-sequence, single-dose, crossover, comparative oral bioavailability study was conducted in non-smoking adult male healthy volunteers between the ages of 18 and 45 years. The study was performed in accordance with the basic principles defined in the US 21 CFR Part 312.20 and the principles enunciated in the Declaration of Helsinki (World Medical Association Declaration of Helsinki). The subjects were given a single oral 1 g dose with a washout period of 10 days. Pharmacokinetic profiles included blood levels at 0, 0.25, 0.5, 0.75, 1, 1.25, 1.5, 1.75, 2, 2.5, 3, 4, 6, 10, 12, 16, 20, 24, 30, 36, and 48 hours following each dose. The formulations were MMCept 500 mg tablets and Cellcept 500 mg tablets. Subjects were fasted overnight and for 4 hours postdosing. Mycophenolic acid (MPA) concentrations were determined using HPLC. Physical examinations, hematology, urinalysis, and serum chemistry tests including liver enzymes were performed at screening and at the end of the study. Subjects were monitored for safety and adverse events throughout the study. Both products showed similar bioavailability. The LSM were within the limits for FDA approval (80 to 125), suggesting that the two products are equivalent and switchable.

Adult↗

PubMedDate not supplied

NMR imaging in the evaluation of orbital tumors.

The application of nuclear magnetic resonance (NMR) imaging to the diagnosis of orbital space-occupying lesions was studied in group of 28 patients with a wide range of pathology. The NMR findings in six patients are illustrated. The results of the NMR scans are compared with the information that can be derived from conventional neuroradiologic procedures, including computed tomography. The value of the multiplanar facility of NMR is emphasized. It provides accurate volumetric information and establishes the precise topographical relationships of tumors to normal structures. The muscle cone and the optic nerve can be identified in the axial, coronal, and sagittal planes. Current limitations of the method and possible future developments to improve diagnostic precision are discussed.

Cranial Nerve Neoplasms↗