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Biomedical subjects

M Zakaria

Publications and source records attributed to M Zakaria.

25 records · Page 2Linked to original sources
PubMed1979

Diagnosis of neural crest tumors by reversed-phase high-performance liquid chromatographic determination of urinary catecholamine metabolites.

Aberrations in the metabolic pathways of catecholamines in patients with neural crest tumors result in characteristic urinary excretion patterns of their catabolites. Tumors such as pheochromocytoma, neuroblastoma and ganglioneuroma usually defy clinical diagnosis because of their rarity, small size, intraabdominal position and clinical symptoms similar to those of essential hypertension. Quantitative determination of catecholamine metabolites such as vanillylmandelic acid (VMA) and 3-methoxy-4-hydroxyphenylethyleneglycol (MHPG) offers possibilities for reliable confirmation of diagnosis. However, previous techniques for the assessment of catabolite levels suffered from inadequate sensitivity, reproducibility or specificity, which seriously diminished their usefulness as biochemical determinants in the prognosis of these life-threatening tumors. Reported in this paper is the analysis of urinary levels of VMA and MHPG using reversed-phase high-performance liquid chromatography with electrochemical and sectrophotometric detection. We present the excretion patterns showing these metabolites in 15 control subjects, 15 patients with pheochromocytoma and 5 patients with neuroblastoma.

Catecholamines↗
PubMed1979

Use of reversed-phase high-performance liquid chromatographic analysis for the determination of provitamin A carotenes in tomatoes.

The usual methods for provitamin A evaluation of foods convert the total pigment amount, determined spectrophotometrically, into vitamin A units. Since the totally inactive lycopene is the major carotenoid in the tomato, such readings result in erroneously high provitamin A values. In view of the recent development of chemically bonded, reversed-phase, microparticulate packings and their use in high-performance liquid chromatography which combines highly accurate and reproducible resolution with the speed and ease of operation, a new method using such a system was developed to isolate carotenoid pigments from tomato samples. A 15-min column separation was thus achieved, dramatically decreasing the analysis time of the classical open column chromatographic procedures, which often result in unresolved and altered fractions due to long-term exposure to oxygen, light, solvents and sometimes adsorbent. beta-Carotene and lycopene were determined and quantitated in six tomato samples. beta-Carotene, 100% vitamin A-active, was expressed in International Units of vitamin A. The newly developed method gives a more reliable evaluation of the fruit potency in vitamin A than the methods of the Association of Official Analytical Chemists currently used for food composition tables.

Carotenoids↗
PubMedDate not supplied

Anomalous origin of the left coronary artery from the pulmonary artery in an adult: tubular reconstruction of the left main coronary artery under coronary perfusion.

A 38-year-old female with anomalous origin of the left coronary artery (LCA) from pulmonary artery was surgically corrected by tubular reconstruction of the left main coronary artery (LMCA) using the pulmonary artery wall, and this repair was performed under beating heart. Thus, the pulmonary artery was divided above the orifice level and just above the pulmonary valve, and the commissure between nonfacing and left side sinuses was dissected away from the pulmonary artery wall to obtain lateral flaps. The pulmonary artery defect was reconstructed with a roll using an autologous pericardial patch, while the detached commissure was suspended on the pericardial patch. The long tube constructed using pulmonary artery tissue was anastomosed to the anterior aspect of the ascending aorta. These procedures were performed under beating heart simply by clamping the LMCA, since the preoperative myocardial contrast echocardiography confirmed the adequate coronary collateral flow from the right circulation. The postoperative course was uneventful, and a coronary artery angiogram demonstrated a widely patent LMCA. Our experience suggests that, in adult cases, this procedure could be performed without myocardial ischemia simply by clamping the LMCA because of well-developed coronary collateral arteries. The safety of this technique could be confirmed by myocardial contrast echocardiography.

Adult↗
PubMedDate not supplied

[A case of carcinoma of the cervical esophagus treated with interposition of an intestinal loop revascularized using a microsurgical technique].

The Authors present a case of hypopharyngeal tumor in which digestive continuity was assured by a jejunal autotransplant. Tumoral exeresis and jejunal preparation were carried out at the same time by two surgical teams. The use of microsurgical techniques assures the revascularization of the neck transplant by implementing the superior thyroid artery and the internal jugular vein. Digestive anastomoses complete the operation.

Esophageal Neoplasms↗