Composition and quality of Mexican and imported retail beef in Mexico.

Randomly selected New York steaks from domestic and imported beef were purchased in three major Mexican cities, comparing Mexican beef (from northern, central, and southern regions of the country) and American beef (USDA-Choice and ungraded No Roll). The meat was analyzed for chemical composition, Warner-Bratzler shear force (WBSF), cooking loss, color and consumer acceptability. All sources of Mexican beef and No Roll US beef had similar chemical composition. USDA-Choice beef had a higher fat content and a lower moisture and total collagen content. Mexican beef from the northern region and USDA-Choice beef had lower WBSF and redness values than the other beef sources. Overall desirability was high regarding all Mexican beef sources, and USDA-Choice beef. No Roll US beef had the lowest overall desirability score. Results indicate Mexican beef is in an advantageous position when competing with imports in the current open market.

Vasculitis retiniana primaria / Primary retinal vasculitis

Caso clínico: Presentamos el caso de una mujer de 22 años de edad, de raza caucásica, que consultó por un breve episodio de visión borrosa en su ojo derecho (OD). Los hallazgos funduscópicos mostraron marcada tortuosidad venosa, hemorragias redondeadas en área paramacular de OD y leve tortuosidad venosa en el ojo izquierdo. El estudio angiográfico confirmó una vasculitis venosa segmentaria, de vasos intermedios confinada al polo posterior del OD. El estudio complementario descartó patología sistémica asociada. El cuadro evoluciona a la remisión con tratamiento corticoideo oral.Discusión: El diagnóstico de vasculitis retiniana primaria se realiza mediante estudio oftalmológico y angiográfico. Estudios previos demuestran no existir indicación de realizar pruebas complementarias en busca de una posible asociación sistémica (AU)

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[Primary retinal vasculitis]. / Vasculitis retiniana primaria.

CASE REPORT: We present the case of a 22-year-old Caucasian female who consulted because of a brief episode of blurred vision in her right eye. Funduscopic findings in right eye included marked venous tortuousness and roundish paramacular haemorrhages. A slight venous tortuousness in left eye. Fluorescein angiography showed a segmentary retinal vasculitis affecting medium calibre vessels of the posterior pole. Complementary examinations ruled out any systemic involvement. After therapy with oral corticoesteroids the case evolves to remission. DISCUSSION: The diagnosis of retinal vasculitis is achieved by the performance of ophthalmoscopy and fluorescein angiography. Prior studies have ruled out the need for complementary examinations to find any systemic involvement in patients.

Continuous production of 5'-ribonucleotides from yeast RNA by hydrolysis with immobilized 5'-phosphodiesterase and 5'-adenylate deaminase.

The production of 5'-IMP and 5'-GMP by enzymatic conversion from RNA using a continuous two packed-bed reactor was investigated. 5'-Phosphodiesterase (5'PD) and 5'-adenylate deaminase (5'AD) were immobilized in an acrylic resin to produce derivatives with about 15 U/g of support. The kinetic properties of the enzymes were described by Michaelis-Menten models: no significant differences were found in the K m value of the free and immobilized 5'AD (60 and 20 µM, respectively), whereas for 5'PD the K m value was one order of magnitude higher for the immobilized enzyme (4.85 mg RNA/ml), probably due to diffusional limitations. Both enzymes remained stable after 8 h of use in a continuous packed-bed reactor whereas the half lives of the free enzymes were 193 min and 240 min at 40°C and 70°C for 5'AD and 5'PD, respectively. A procedure is proposed for the design of a continuous two packed-bed column process.

Posttraumatic reaction in a case of fundus flavimaculatus with atrophic macular degeneration.

We report the case of a 13-year-old girl who had fundus flavimaculatus with atrophic macular degeneration. At the age of 14 years, she suffered mild trauma OD, subsequently developing a fibroglial reaction of the retina and pigmentary migration. The coexistence of both phenomena could be explained by the liberation of growth factors by the damaged retinal pigment epithelial (RPE) cells as a reaction to the injury and/or by the passage of chemoattractants from the serum through the damaged RPE cell barrier.

Fatal acute myocardial infarction after intravenous fluorescein angiography.

Since its introduction, fluorescein angiography has been widely used to investigate diseases of the ocular fundus. A case of fatal acute myocardial infarction after intravenous fluorescein angiography is presented. This appears to be the first case documented by autopsy in which the findings are compatible with myocardial infarction as the cause of death. Although there are no known contraindications for fluorescein angiography in patients with a history of cardiovascular disease, the indications for this elective procedure should be carefully reviewed in such patients. Adequate emergency resuscitation equipment should be available in the fluorescein angiography suite.

[Usher syndrome. Two case reports]. / Síndrome de Usher. A propósito de dos casos.

Usher's syndrome is an autosomal, recessively inherited trait that combines a congenital hearing impairment with retinitis pigmentosa. The AA. present the cases of two brothers affected. The actual classification and the last etiopathogenic theories are revised.

[Transurethral resection using glycine irrigation]. / Résection endoscopique sous irrigation de glycine.

An accident is described which occurred during a transurethral resection of a prostatic adenoma using a 1.5% glycine solution in a 68 yr old patient. The surgery was performed under spinal anaesthesia with bupivacaine. After 14 l of irrigation fluid had been used, visual disturbances, bilateral mydriasis and drowsiness appeared, with no haemodynamic disturbances. Three hours after the end of surgery, there appeared convulsions, with the blood sodium level at 118 mmol X l-1. Symptomatic treatment resolved the problem, and the clinical examination was normal 12 h after surgery. The role of hyponatraemia in the clinical state is discussed. The usefulness of regional anaesthesia in the early detection of this type of accident is recalled.