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Biomedical subjects

M Castillo

Publications and source records attributed to M Castillo.

At least 235 records · Page 13Linked to original sources
PubMed1989

HIV-associated lymphocytic interstitial pneumonia: radiologic manifestations and pathologic correlation.

The authors reviewed chest radiographs of 16 patients with biopsy-proved lymphocytic interstitial pneumonia (LIP) who also had acquired immunodeficiency syndrome (AIDS) or AIDS-related complex (ARC). Radiographs revealed fine reticular or reticulonodular infiltrates in the pulmonary interstitium in five patients, coarse reticulonodular infiltrates in two, and reticular or reticulonodular opacities with superimposed patchy alveolar infiltrates in nine. Pathologic examination of biopsy specimens revealed lymphocytes, plasma cells, and reticulum cells aggregated about the small arteries and compressing the distal airways. Throughout the course of AIDS or ARC, the radiographic findings of LIP remained stable in 12 of 16 patients. AIDS/ARC-related LIP appears to be a benign reaction of bronchial-associated lymphatic tissue to the human immunodeficiency virus (HIV). However, this indolent process cannot be correctly diagnosed based on radiographic findings alone; the use of lung biopsy is required to differentiate LIP from other infections. The authors suggest that patients with these radiographic findings, HIV seropositivity, but no other signs of opportunistic infection or neoplasia should be classified as having AIDS.

AIDS-Related Complex↗
PubMed1989

Influence of protein content of diet on growth and lipid composition of European eel muscle and liver.

The influence of diet protein content (35-45-55%) on growth and lipid composition of muscle and liver of European eel (Anguilla anguilla) was studied for the first time. In control eel, triacylglycerols constituted about 90% of total lipids in muscle and about 40% in liver. Triacylglycerol content in eel muscle significantly increased after two months of treatment with any diet assayed, with independence of protein content and source. In liver, this increase was comparatively higher in herring meal diets. Total phospholipid content in both muscle and liver drastically decreased after one month of all the experimental treatments, although some recuperation was found at the second month. No significant differences in lipid composition of muscle eel were found among the various experimental groups, in spite of the differences observed in the body weight gain.

Anguilla↗
PubMed1988

Detection of lytic antimycobacterial antibodies by immune lysis of liposomes sensitized to tuberculin.

Two procedures were used in order to incorporate purified protein derivative tuberculin (PPD) from M. tuberculosis, strain H37Rv, into calcein-containing liposomes: formation of multilamellar vesicles (MLV) in a PPD solution or exposure of preformed MLV to this solution. Immune lysis of these PPD-sensitized MLV was studied in the presence of a hyperimmune anti-M. tuberculosis sheep serum using a specific pathogen-free rabbit serum as a source of complement. A 50% release of encapsulated calcein was observed spectrofluorometrically after 30 min and remained unchanged up to 2 h. The release of calcein in the absence of complement or of anti-H37Rv serum or by liposomes which did not contain PPD never exceeded 1-2%. Liposomes formed in PPD solution were more sensitive to anti-H37Rv serum than preformed liposomes exposed to PPD. Trials with human sera from ten tuberculous patients revealed the presence of specific lytic immunoglobulins. In the presence of sera from skin test negative, non-tuberculous subjects, calcein release was significantly lower. This opens the way to a new method for the study of the humoral immunity in tuberculosis.

Animals↗
PubMed1988

Insulin sensitivity in anorexia nervosa: a mirror image of obesity?

Although, in many respects and from a metabolic point of view, obesity and AN are clearly two opposite pathological conditions, the available data concerning insulin sensitivity in these two syndromes are not so obviously opposite. Indeed, whereas everybody is convinced that obesity is characterized by an increased insulin resistance, the papers reporting insulin sensitivity parameters in AN contain some apparently contradictory results. The observations of simultaneously low fasting blood glucose and plasma-insulin levels in anorectic patients could suggest increased insulin sensitivity in AN. However, if this is the case, it would be present despite other metabolic and hormonal changes (increased plasma concentrations of free fatty acids, cortisol, and growth hormone) which are known factors of insulin resistance. During an oral glucose-tolerance test, an impaired glucose-tolerance occurring despite sustained insulin response to glucose is usually found in anorectic patients before treatment; these abnormalities are, at least partially, reversed after successful refeeding. From these results, such conclusive, if indirect, evidence exists for relative insulin insensitivity in untreated AN. Similar results were initially reported with the intravenous glucose-tolerance test. Typically, the coefficient of glucose assimilation K was reduced in anorectic patients before treatment and increased after realimentation. This seemed to occur despite a relative increase in insulin response to glucose, which again may be related to insulin resistance in these undernourished subjects. However, more recent data demonstrated that the early insulin response is significantly lower in anorectic patients than in controls and that more than half of these patients have normal glucose-tolerance despite decreased peripheral plasma insulin levels. These latter observations, on the contrary, suggest an increased insulin sensitivity, at least in some patients with AN. Only the recently developed minimal model method allows us to discriminate between changes in insulin secretion and action after intravenous glucose injection and thus to infer accurately the sensitivity of the tissues to insulin. Unfortunately, this technique has not been applied to anorectic patients, until now, to solve the controversy. The simplest way to assess the action in vivo of insulin is to perform an intravenous insulin-tolerance test. However, the initial findings with this test, which showed exaggerated fall in plasma-glucose values and delayed return to basal levels after intravenous injection of insulin in AN, do not necessarily mean increased insulin sensitivity in these self-starved patients.(ABSTRACT TRUNCATED AT 400 WORDS)

Anorexia Nervosa↗
PubMed1988

Percutaneous needle evaluation of intradural extramedullary lesions of the lumbar spine.

A total of eight patients in whom five intradural extramedullary lesions and three epidural lesions were present were evaluated by percutaneous needle biopsy. In four patients the level of aspiration biopsy was determined using the initial myelogram and in those patients fluoroscopic guided percutaneous needle biopsies were performed. Three of these patients had large intradural extramedullary masses (above 1 cm); one patient had an epidural lesion. Diagnostic material was obtained in all cases (medulloblastoma, astrocytoma, small cell carcinoma, adenocarcinoma). Immediate post procedure CT and clinical followup showed no complications. In three patients with small lesions (below 1 cm), post myelographic CT was used to determine the level of aspiration. Post myelographic CT showed an intradural extramedullary mass in one patient and epidural lesions in two cases. Plain CT showed a high attenuation lesion in one patient. CT guided percutaneous needle biopsies in these four patients yielded diagnostic specimens (neurofibroma, uroepithelial carcinoma, hematoma, Thorotrast deposit). Clinical follow up showed no complications. Our experience indicates that percutaneous needle biopsy of intradural extramedullary and epidural lesions of the lumbar spine is safe and efficacious. Depending upon the size of the lesions, myelography or CT can be utilized to determine the level of aspiration.

Adult↗
PubMed1988

Effect of experimental hyperphenylalaninemia induced by dietary phenylalanine plus alpha-methylphenylalanine administration on amino acid concentration in neonatal chick brain, plasma, and liver.

Supplementation of 5% phenylalanine plus 0.4% alpha-methylphenylalanine to the standard diet or 1% phenylalanine plus 0.08% alpha-methylphenylalanine to the drinking water produced phenylketonuria-like conditions in 5-day-old chicks. An increase of 10 to 15-fold in the phenylalanine content was observed in plasma or brain of animals after 9 days of both types of treatment. A smaller but significant increase was also observed in liver. However, practically no changes were found in the levels of tyrosine in the same conditions. Thus, the high values of plasma and brain phenylalanine/tyrosine ratio obtained by these treatments were mainly due to an increase in the phenylalanine levels, without increasing those of tyrosine. Chronic hyperphenylalaninemia induced a nonsignificant decrease in the most of amino acid contents in brain, especially after 9 days of treatment, although the levels of glycine and serine were significantly increased. A similar decrease was found in the plasma and liver concentration of various amino acids, although the variations observed in the liver were smaller than those found in plasma and brain.

Amino Acids↗
PubMed1988

Inhibition of brain and liver 3-hydroxy-3-methylglutaryl-CoA reductase and mevalonate-5-pyrophosphate decarboxylase in experimental hyperphenylalaninemia.

Experimental hyperphenylalaninemia has been induced in 5-day-old chicks by dietary treatments with phenylalanine and alpha-methylphenylalanine. An increase of nearly 8-fold in plasma Phe/Tyr ratio was found after 4 days of supplementation the standard diet with 5% phenylalanine plus 0.4% alpha-methylphenylalanine. The increase in this ratio was about 13-fold after 9 days of the same treatment. Similar results were observed in brain and liver, although the increases were smaller than those found in plasma. Total body, brain and liver weight decreased after 9 days of treatment. Phenylalanine plus alpha-methylphenylalanine administration to 5-day-old chicks produced a significant decrease in the 3-hydroxy-3-methylglutaryl-CoA reductase and mevalonate-5-pyrophosphate decarboxylase specific activities from both brain and liver. These results demonstrated for the first time that experimental hyperphenylalaninemia inhibited different enzyme activities directly implicated in the regulation of cholesterogenesis. Therefore, a reduced cholesterol synthesis in brain may evidenciate the theory of an impaired myelination leading to mental retardation in phenylketonuria patients.

Acyl Coenzyme A↗
PubMed1988

Spectrophotometric determination of the stability of an ampicillin-dicloxacillin suspension.

The degradation rate constants for ampicillin and for dicloxacillin in the suspension filtrate, and their solubility coefficients (at 25 degrees C) were determined by spectrophotometry employing a multicomponent computer program. The shelf life of the ampicillin-dicloxacillin suspension was then determined in terms of the stability of ampicillin, the least stable component.

Journal Article↗
PubMed1988

Hemangiosarcoma of the left foot and tibia: case report.

A case of a hemangiosarcoma involving the bones of the foot in a diabetic patient who had swelling of the left foot is reported. Radiographs demonstrated multiple lytic areas throughout the bones of the foot. Clinically and radiographically, infection was suspected, but the biopsy revealed the presence of tumor. Metastases to the tibia were found and an above the knee amputation was performed. Chemotherapy was given, but 6 months later the patient died. Hemangiosarcoma is known to involve the different bones of the foot in a "multicentric" fashion and should be considered in the differential diagnosis of lytic lesions of multiple bones of the lower extremities.

Bone Neoplasms↗
PubMed1988

Syringomyelia as a consequence of compressive extramedullary lesions: postoperative clinical and radiological manifestations.

MR imaging was performed to determine the cause of the onset of new neurologic symptoms in five patients who had previously undergone surgical excision of extramedullary masses. Syringomyelia and the absence of recurrent or residual lesions were documented in all cases. Three patients showed long cysts (multiseptated in two and smooth in one) with low signal intensity on both T1- and T2-weighted images. The flow-void phenomenon related to fluid motion in these three cysts, which were enlarging clinically, was responsible for the hypointensity on the T2-weighted images. In two patients the fluid within the lesions behaved similarly to normal nonpulsatile CSF and may have represented syrinx cavities in a state of "arrested growth." Three patients had surgical decompression under real-time intraoperative sonographic control, which showed the presence of intramedullary cyst-fluid pulsations in two cases and the absence of cyst-fluid pulsations in one case. These sonographic observations correlated with the MR findings. We postulate that these syrinx cavities form as a result both of the effect that the original extramedullary lesion had upon the underlying spinal cord and the subsequent postoperative alterations in the CSF dynamics at the level of prior surgery. Syringomyelia should be considered in patients with recurrent or new symptoms who previously had surgery for extramedullary lesions.

Adult↗
PubMed1987

Effect of clofibrate on brain mevalonate-5-pyrophosphate decarboxylase.

The effect of clofibrate on the activity of the three mevalonate-activating enzymes has been studied for the first time in brain by reactions carried out using [2-14C] mevalonic acid as substrate and 105,000 g supernatants from 14-day-old chick brain. Mevalonate-5-pyrophosphate decarboxylase was clearly inhibited, while mevalonate kinase and mevalonate-5-phosphate kinase were not significantly affected. The effect of clofibrate on decarboxylase activity was progressive with increasing concentrations (1.25-5.00 mM) of the inhibitor. A transient inhibition and a subsequent activation as a function of clofibrate concentration seemed to occur for mevalonate kinase. Direct measurements of decarboxylase activity utilizing [2-14C] pyrophosphomevalonate as the specific substrate of this enzyme corroborated these results. Kinetic studies showed that clofibrate competes with the substrate ATP.

Animals↗
PubMed1987

Spontaneous rupture of the membranes, functional dystocia, oxytocin treatment, and the route of delivery.

The details of clinical management were examined in 96 nulliparous patients with functional dystocia who had spontaneous rupture of the membranes before admission and were treated with oxytocin in the first stage of labor. It was our hypothesis that if the allegedly "high" rate of cesarean sections was the result of mediocre or flawed practices, these should be most evident in patients delivered abdominally. A group of 59 patients delivered vaginally were compared with 37 patients delivered by cesarean section. The means of many variables were not statistically different. The cesarean section group was characterized by smaller stature, a lesser cervical dilatation rate both before and after oxytocin administration, a larger maximum oxytocin dose, a longer period of oxytocin administration, more frequent cessation of oxytocin administration or dose reduction because of hypercontractility or an abnormal fetal heart rate or both, and a higher incidence of intra-amniotic infection. We conclude that the decision to perform cesarean section in nulliparous women with functional dystocia arises from disabilities of the patient and not from differences in the application of our management principles, services, or treatments.

Cesarean Section↗