Effect of light and calcium on cyclic GMP synthesis in rod outer segments of toad retina.

The rod outer segments of toad retina contain a guanylate cyclase activity of about 3 +/- 1 nmol of cGMP formed/min per mg protein. In darkness this value is largely independent of the Ca2+ concentration, although it is enhanced by light upon lowering the Ca2+ concentration from 10(-5) to 10(-8) M. The activating effect of light on cyclase at low Ca2+ concentrations is enlarged upon increasing the light intensity. With a flash of light bleaching 7 X 10(-2) percent of rhodopsin, cyclase activity increased by a factor of 30 when Ca2+ levels dropped from 10(-5) to 10(-8) M. In view of recent observations that shortly after a flash of light the calcium activity inside the photoreceptor cell decreases, it seems likely that Ca2+ plays a regulatory role on cGMP metabolism in visual excitation.

Nizatidine in the short-term treatment of duodenal ulcer--an Italian Multicenter Study.

One hundred and seventy three patients suffering from duodenal ulcer, were selected for a double-blind, controlled and randomized parallel multicenter study, with interval endoscopic examinations. This study was undertaken to compare the efficacy and safety of nizatidine administered at a single dose (300 mg "nocte") versus ranitidine (300 mg "nocte") in the treatment of acute duodenal ulcer. One hundred and sixty five patients were found to meet every admission criterion and completed the study (86 on nizatidine and 79 on ranitidine). On admission to the study, both groups were seen to have been correctly selected and epidemiologically well-distributed as to history of duodenal ulcer, previous treatments and pre-study symptoms. The ulcer was considered healed when complete re-epithelialization had occurred in areas of ulcerated mucosa. Healing rates of duodenal ulcer proved to be globally similar in the two groups, both in the 4th week (nizatidine, 78%; ranitidine, 78%) and in the 8th week (nizatidine, 91%; ranitidine, 95%). After four weeks of treatment, 67% of the patients treated with nizatidine no longer had any symptoms, while 87% patients no longer suffered from day pain, and 91% had no nocturnal pain. As a result, intake of antacids quickly decreased during the first four weeks. A similar response was observed in the group receiving ranitidine. After administration at a single dose of 300 mg in the evening, nizatidine proved to be at least as effective and safe as 300 mg of ranitidine administered in the same way, with respect both to ulcer healing and symptom response.

Short-term treatment of reflux oesophagitis with ranitidine 300 mg nocte. Italian multicentre study.

A multicentre study involving 9 Italian institutions was carried out to compare the efficacy and safety of ranitidine 150 mg b.i.d. and ranitidine 300 mg nocte in the treatment of reflux oesophagitis. 117 patients with histologically proven oesophagitis were randomly allocated to two comparable treatment groups. Efficacy and reliability were evaluated by clinical and laboratory tests at the beginning of the study, and at 3 and 6 weeks; endoscopy and biopsies were performed at the beginning and at 6 weeks. Treatment with ranitidine for 6 weeks led to total disappearance of gastro-oesophageal reflux symptoms in 60% of patients, with percentages of partial improvement varying between 85% and 95% of cases. Improvement in the results of endoscopic examination was 85%, of which 55% were cured. Microscopic examination revealed an improvement of 36% and 44%, with a cure rate of 18% and 26% respectively. With regard neither to the regression of symptoms nor to the macroscopic and microscopic inflammation of the oesophageal mucosa did statistical examination show significant differences in the therapeutic efficacy of ranitidine 150 mg b.i.d. or 300 mg nocte for treatment of reflux oesophagitis.

A case of cerebral sparganosis in South America.

Cerebral sparganosis (CS) is a parasitic infection caused by the larva of Spirometra mansonoides. Rarely it can affect the human brain. We report the case of a 24-year old man from Paraguay who suffered from seizures and headache for one year. A frontal tumor was diagnosed by CT-scan and was subsequently resected. The pathological examination revealed a larva with Sparganum characteristics. The evolution of the patient was satisfactory. As far as we know, this is the first case of CS reported in South-America.

[Neurocysticercosis in a hospital of the city of Buenos Aires: study of 11 cases]. / Neurocisticercosis en un hospital de la ciudad de Buenos Aires: estudio de once casos.

Eleven patients with diagnosis of possible neurocistycercosis were studied in our Department since 1986. All of them were adults. Eight were Bolivian citizens. The commonest neurological clinical manifestation were seizures and/or headache. Brain CT scans showed cystic lesions and calcifications in 5 patients, only calcifications in 3, enlarged ventricles in 2 and an isolated frontal cystic lesion in 1. Six out of 7 patients who were submitted to spinal fluid ELISA test showed positive response for cysticercosis. Patients were put on praziquantel (50 mg/Kg/d) or albendazol (15 mg/Kg/d) with good outcome for all them. Surgery was carried on for treatment of enlarged ventricles (2 patients) and for a like-expansive lesion (1 patient). The aim of this work is to underscore the fact that in Buenos Aires city, which previously was not within the endemic latin american area for cysticercosis, is now possible to find patients with the neurological manifestations of this parasitosis, most probably due to migration of people coming from the north provinces or from countries situated at its border where the disease is endemic.

[Acute extra-axial hematoma post-traumatic of the clivus]. / Hematoma agudo extra-axial post-traumático de clivus.

Magnetic Resonance Imaging (MRI) has amply shown its usefulness for the evaluation of traumatic cranio-encephalic lesions, particularly those involving the posterior fossa, due to the absence of bone artifacts, the availability of multiplanar sections and the greater sensitivity as regards Computerized Tomography (C. T.). We present an MRI examination of an extra-axial hematoma of the clivus in a child with head trauma, not visible on C. T. scans.

[Acute meningitis caused by Streptococcus agalactiae in adult patient with a spinal fluid fistula]. / Meningitis aguda por Streptococcus agalactiae en una paciente adulta con fístula de líquido cefalorraquídeo.

Acute meningitis in adults caused by Streptococcus agalactiae is a rare entity. To our knowledge, there are only two cases associated with a central spinal fluid fistula published in the English literature from 1942 to the present. We report the third case. It was diagnosed in a 60-year-old woman with a twelve-year history of cerebrospinal rhinorrhea after a blunt head trauma. A CT scan of the base of the skull with administration of intrathecal contrast showed a disruption of the posterior and superior aspect of the sphenoid sinus with central spinal fluid leakage.

[Diagnosis and treatment of spinal epidural abscess]. / Diagnóstico y tratamiento del absceso epidural espinal.

Spinal epidural I abscess is an uncommon disease. The medical literature emphasizes the importance of its timely recognition and treatment. Three patients admitted in our hospital are presented. None of them was diagnosed on ambulatory bases. All of them were admitted because of spinal ache and two of them also had fever. Magnetic resonance imaging yielded the correct diagnosis in all cases and was very effective in delineating the extent of the lesion. We used antimicrobial therapy directed against the bacteria identified by cultures as well as surgical drainage in all cases. The three patients had a good outcome and no neurologic sequela. Early recognition, proper microbiologic diagnosis and surgical drainage are the main criteria for the current management of spinal epidural abscess.

Comparison of once-daily bedtime administration of famotidine and ranitidine in the short-term treatment of duodenal ulcer. A multicenter, double-blind, controlled study.

A multicenter, double-blind, randomized, controlled study was conducted in 234 duodenal ulcer patients to compare the efficacy and safety of the H2-receptor antagonists famotidine and ranitidine in the treatment of duodenal ulcer. Patients received 40 mg famotidine (119 patients) or 300 mg ranitidine (115 patients) once daily at bedtime for 4 weeks. If ulcer lesions persisted, treatment was extended to 6 weeks. Efficacy was assessed by relief of symptoms and endoscopic findings of ulcer healing. Safety was determined on the basis of reports of side effects, results of laboratory tests, and, in selected patients, changes in plasma levels of hormones. The 4- and 6-week healing rates achieved with famotidine were 76% and 91%, respectively, and with ranitidine they were 76% and 87%, respectively; the differences in healing rates for the two drugs were not statistically significant. Similarly, both drugs provided satisfactory relief of pain and dyspeptic symptoms. However, famotidine produced significantly (P less than 0.05) greater relief of postprandial fullness and heartburn. The incidence of untoward effects was low in both treatment groups, and abnormal results in laboratory tests were observed in only one patient, a chronic alcoholic receiving famotidine, who withdrew from the study because of a slight elevation in serum transaminase levels. One patient in the ranitidine treatment group dropped out of the study because of a generalized urticarial rash; however, a causal relationship between drug and effect could not be established. The authors conclude that famotidine may be regarded as the best alternative to ranitidine in the treatment of duodenal ulcer.

Structure of a protein catalyzing the formation of 11 cis-retinal in the visual cycle of invertebrate eyes.

A pigment made up of a protein able to bind retinal as well as retinol is described. The molecule consists of a dimer with a molecular weight of 50,000 which binds one molecule of retinal. The binding site for retinal is a Schiff base buried in the interior of the protein. Retinol is probably bound to the protein in the same site as for retinal, although not covalently, as suggested by the absorbance spectra. The protein, extracted from honeybee retina, is involved in visual pigment metabolism, and its structure may elucidate the mechanism of the stereospecific photoisomerization of all trans-retinal to 11-cis-retinal.

Neurocisticercosis en un hospital de la ciudad de Buenos Aires: estudio de once casos / Neurocysticercosis in a hospital of the city of Buenos Aires: study of 11 cases

Fueron examiandos 11 pacientes adultos con el diagnostico presuntivo de neurocisticercosis, 8 de ellos provenientes de Bolivia y los restantes del interior de la Argentina. Como manifestación clínica inicial el 82 por ciento de ellos mostro convulsiones t el 73 por ciento cefaleas. Ambas alteraciones podian estar combinadas en el mismo paciente o presentarse en forma independiente. La tomografia computada de cerebro evidencio calcificaciones y quistes en 5 enfermos, solo calcificaciones en 3, hidrocefalia en 2 y un unico quiste en 1. En 7 casos se efectuo ELISA en el LCR, de ellos 6 resultaron positivos. El tratamiento medico se hizo en base a la administración de praziquantel o albendazolcon buena evolución de los pacientes en todos los casos. El tratamiento quirurgico fue indicado en el caso en que una lesión actuase como masa ocupante con aumento de la presión endocraneana (1 caso) o produjera obstrucción de la circulación del LCR llevando a una hidrocefalia (2 casos). El estudio presente pretende alertar sobre la posibilidad que nuevas regiones, como la Ciudad de Buenos Aires, puedan ingresar dentor del area endemica latinoamericana a consecuencia de los movimientos migratorios internos y externos y el asentamiento de portadores de la parasitosis en el perimetro urbano

Hematoma agudo extra-axial post-traumático del clivus / Acute extra-axial hematoma post-traumatic of the clivus

La Resonancia Magnética ha demostrado ampliamente su utilidad en la evaluación de lesiones traumáticas cráneo encefálicas, particularmente a nivel de la fosa posterior, debido a la ausencia de artefactos óseos, capacidad de realizar secciones multiplanares, y su mayor sensibilidad con respecto a la Tomografia Computada (T.C.). Aqui presentamos el estudio de un hematoma agudo extra-axial post-traumático del clivus en un niño que habia sufrido un traumatismo craneano, no visualizado en los estudios de T.C