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Biomedical subjects

S Castro

Publications and source records attributed to S Castro.

At least 55 records · Page 3Linked to original sources
PubMed1989

Solubilization of the N-methyl-D-aspartate receptor channel complex from rat and porcine brain.

The N-methyl-D-aspartate (NMDA) receptor complex as defined by the binding of [3H]MK-801 has been solubilized from membranes prepared from both rat and porcine brain using the anionic detergent deoxycholate (DOC). Of the detergents tested DOC extracted the most receptors (21% for rat, 34% for pig), and the soluble complex, stabilized by the presence of MK-801, could be stored for up to 1 week at 4 degrees C with less than 25% loss in activity. Receptor preparations from both species exhibited [3H]MK-801 binding properties in solution very similar to those observed in membranes (Bmax = 485 +/- 67 fmol/mg of protein, KD = 11.5 +/- 2.9 nM in rat; Bmax = 728 +/- 108 fmol/mg of protein, KD = 7.1 +/- 1.6 nM in pig, n = 3). The pharmacological profile of the solubilized [3H]MK-801 binding site was virtually identical to that observed in membranes. The rank order of potency of: MK-801 greater than (-)-MK-801 = thienylcyclohexylpiperidine greater than dexoxadrol greater than SKF 10,047 greater than ketamine, for inhibition of [3H]MK-801 binding, was observed in all preparations. The receptor complex in solution exhibited many of the characteristic modulations observed in membranes.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed1986

Post-traumatic diffuse axonal brain injury. Analysis of 78 patients studied with computed tomography.

A group of 78 severe head injury patients showing computerized tomography (CT) findings of the so-called "diffuse axonal injury" is analyzed. These patients represent 20% of the authors' series of severe head injury. Twenty-three patients showed small intraparenchymal haemorrhages in the CT scan study, 15 intraventricular haemorrhage and 40 patients had both intraparenchymal and intraventricular haemorrhages. Signs of brainstem haemorrhagic contusion were seen in 29 (38%) patients. Generalized brain swelling superimposed on the above findings was present in 75% of the cases. Raised intracranial pressure, which was found in 50% of the patients, correlated with the presence of ventriculocisternal collapse in the CT scan and an unfavourable outcome. Only 4 patients in this series made a good recovery, 13 developed a moderate disability, 11 a severe disability, 12 became vegetative and 38 (49%) died. The prognosis with this post-traumatic lesion is the worst in the authors' severe head injury series after excluding cases with subdural haematoma.

Adolescent↗
PubMed1986

Symptomatic subependymoma: report of four new cases studied with computed tomography and review of the literature.

The authors describe four cases of subependymoma studied with computed tomography (CT) and review 18 previously reported cases in an attempt to define the most characteristic CT presentation of this rare, benign tumor. Subependymoma usually appears as an isodense, or even hypodense, intraventricular tumor on plain CT scan and shows minimal or no enhancement in postcontrast studies. Differential diagnosis between subependymoma and the more malignant true ependymoma is difficult, particularly when the tumor occurs in the posterior fossa. Recognition of subependymoma should prompt the surgeon to attempt radical tumor removal because it can be achieved without sacrificing contiguous tissue and carries a good prognosis.

Adolescent↗
PubMed1986

Normal computerized tomography scans in severe head injury. Prognostic and clinical management implications.

The authors analyze the clinical course of 46 severely head-injured patients who had completely normal computerized tomography (CT) scans through the immediate posttraumatic period (1 to 7 days after trauma). These patients represent 10.2% of a consecutive series of 448 cases of severe head injuries and two-thirds of the cases showing a normal CT scan on admission (the other one-third of the cases developed new pathology). The usual course in these 46 patients after the initial coma was toward progressive neurological improvement, and 35 patients (76%) achieved a functional level of survival. Nine patients (19.5%) remained comatose for several weeks and developed severe disability. There were two fatalities due to medical complications. The final outcome was more closely related to the duration of coma (the longer the duration the worse the result) than to the initial Glasgow Coma Scale (GCS) score. In fact, 26% of the patients in the lower GCS score ranges (3 to 4 points) made a good recovery and 46% developed moderate disability only. These findings indicate that the grim prognostic significance of deep posttraumatic coma is tempered in the presence of a normal scan. However, the absence of CT abnormalities in severely head-injured patients cannot be equated with a good prognosis because in one-fifth of the cases serious permanent disability develops. Sustained elevation of the intracranial pressure (ICP) was not seen in these patients, indicating that ICP monitoring may be omitted in cases with a normal scan. However, since one-third of the patients with a normal admission scan developed new pathology within the first few days of injury, a strategy for control scanning is recommended. Control CT scans performed more than 6 months after injury showed a significantly higher incidence of brain atrophy in patients developing permanent disability than in those who made a good recovery.

Adult↗
PubMed1986

[Association of acromegaly and a cerebral arterial aneurysm disclosed by a subarachnoid hemorrhage].

The association of acromegaly and cerebral aneurysm is an infrequent clinical finding, being few the cases reported in literature. A major incidence of cerebral aneurysm in patients with other pituitary adenoma and cerebral tumour has been described, in relation to the general population. We have studied a male patient, aged 37 years old, with an acromegaly disease initiated 5 years before, that came to our hospital because of subarachnoid hemorrhage symptomatology. A right middle cerebral aneurysm was found in surgery. Hormonal studies confirmed a high basal Growth Hormone (64 ng/ml) that was not suppressed during an Oral Glucose Tolerance Test (75 g). A triple stimulus test (Insulin, TRH, LHRH) demonstrated non-response of GH to TRH and hypoglycemia others hormones were normal. Radiological studies were suggestive of Acromegaly disease. Computed axial tomography showed an intra-sellar tumour. The patient was operated (Transsphenoidal surgery) and a GH pituitary secreting tumour found, without suprasellar extension. The clinical significance and importance of the coexistence of the Acromegaly and Cerebral Aneurysm is discussed, with a review of hypothesis implicated.

Acromegaly↗
PubMed1984

Florida cluster of five children with endodermal sinus tumors. Possible environmental risk.

An unusual case clustering of endodermal sinus tumors in Jacksonville, Fla., is described, together with a variety of local environmental risk factors. Proximity to high-tension electrical power lines was observed, but chance aggregation of familially disposed persons or coincidental environmental factors not identified could also be responsible. However, this cluster is too remarkable to go unreported and is presented here as a preliminary report for those interested in the epidemiology of rare tumors, in an attempt to probe this peculiar episode of cancer. Further investigation of cancer clusters is encouraged, with suggestions to maintain surveillance for these types of clusters in comparably affected areas.

Adolescent↗
PubMed1983

The effect of cyclo-oxygenase and thromboxane synthetase inhibitors on shock induced by injection of heterologous blood in cats.

The injection of rabbit blood into cats causes hypotension, thrombocytopaenia, leukopaenia, a rise in central venous pressure and right ventricular and pulmonary artery pressures and a fall in circulating levels of fibrinogen. Death occurred rapidly after injection of the rabbit blood in 50% of control animals and was associated with respiratory distress. Measurement of plasma thromboxane B2 and 6-oxo PGF1 alpha levels in surviving controls demonstrated a marked elevation in the former with no significant change in the latter. Pretreatment with either the thromboxane synthetase inhibitor, 1-(cyclo octyl methyl) imidazole or aspirin prevented respiratory distress and death and reduced or prevented the elevations in cardiovascular pressures observed in control animals. Neither compound prevented thrombocytopaenia or leukopaenia but did attenuate the rise of thromboxane B2 following injection of rabbit blood. In addition, pretreatment with 1-(cyclo octyl methyl) imidazole resulted in an approximately five-fold increase in circulatory levels of 6-oxo PGF1 alpha five minutes after inducing the shock. We conclude that thromboxane A2 plays an important role in pulmonary (and other organs) dysfunction during the shock induced by injection of heterologous blood. In addition we have shown that inhibition of thromboxane synthetase in vivo under conditions where thromboxane A2 is produced leads to an increase in the synthesis of prostacyclin.

Animals↗
PubMed1981

Validity and reliability of a high school drug use questionnaire among Mexican students.

This study was carried out to ascertain the validity and reliability of data generated through an internationally developed self-administered questionnaire. Data were collected from two student populations in which prevalence of drug use was known (high and low prevalence rates) and information obtained from the questionnaire checked through personal interview. The questionnaire covered both demographic characteristics and drug use items. A total of 474 students were tested and 335 students (70.7 per cent) retested. Although percentages of missing data and inconsistent responses were high, the questionnaire appeared valid and reliable when analysed on a group basis. It was less reliable on an individual basis. In conclusion, it is considered that with minor modifications the questionnaire can be used in the populations studied with enough confidence in validity and reliability to allow comparisons.

Adolescent↗
PubMed1978

Vetebral hemangiomas: spinal angiography and preoperative embolization.

Seven cases of symptomatic spinal hemangiomas are discussed. Special emphasis is given to a patient in whom pre-operative embolization was necessary. A marked reduction in the blood supply was achieved, with the result that the subsequent laminectomy was carried out without great difficulty.

Adolescent↗
PubMed1977

Neurocutaneous melanosis. Report of a case and review of the literature.

A case of neurocutaneous melanosis in a 15 year old male is described. A primary malignant meningeal melanoma caused the death of the patient in six months. The skin lesions were benign. The literature is reviewed, and the nature of the disease and its relationship with other phakomatoses is discussed.

Adolescent↗
PubMedDate not supplied

Factor analysis and somatotyping, are these two physique classification methods comparable?

The aim of this study was to investigate the correspondence of physique structures estimated by the Heath-Carter anthropometric somatotyping method and a factor analysis based on the same set of 10 variables used by Heath-Carter. The investigation was carried out on a group of 200 healthy young adults of 20 years of age who were students of physical education. The mean somatotype was 2.7-4.6-3.0 for the males and 3.3-3.4-3.1 for the females. The 73% of the total variance in males and 75% in females were represented by three factors. They were identified as muscular, fatness and skeletal factors in the males, and in the females as muscular-trunk fatness, skeletal and limb fatness factors. A PCA gives different results depending on the measurements used for the calculation. The same set of variables as for the somatotyping method were used intentionally to extract the PCA factors and to evaluate the possible correspondence between these factors and the Heath-Carter components. On the basis of the correlation between the factors and the somatotype components, one can conclude that there is: (1) a high correspondence between endomorphy and fatness factors in both sexes; (2) that mesomorphy correlated positively with the muscular factor in males and negatively with the skeletal factor in both sexes; and (3) that ectomorphy was highly positively correlated with the skeletal factor and negatively with the other two factors in both sexes. Factors and somatotype components do not correspond exactly which leads to the following conclusions: (1) The three somatotype components cannot be identified as orthogonal factors in a factorial analysis based on the same measurements as for the somatotype, e.g. the ectomorphy component is not an independent factor in males or in females; (2) The muscle measurements and bone width used to estimate mesomorphy in somatotyping scored in two independent factors; and (3) The factor structure of the 10 measurements was sex dependent.

Adult↗
PubMedDate not supplied

Use of erythropoietin in emergencies: massive intoxication by chloramines.

Recombinant human Erythropoietin (rHuEPO) is normally used to correct anaemia in patients with End Stage Renal Disease (ESRD), that are in Regular Dialysis Treatment (RDT). This anaemia is usually due to the existence of two factors: A decrease in the erythropoiesis of the bone marrow and an increase in peripheral haemolysis and, consequently, a decrease in the life span of the red cells.

Anemia↗