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Biomedical subjects

R Miranda

Publications and source records attributed to R Miranda.

At least 91 records · Page 5Linked to original sources
PubMed1991

Endoscopic laser surgery. A single-center comprehensive experience.

A retrospective review of endoscopic procedures using the Nd:YAG laser was carried out for patients treated between October 1985 and March 1989. During this 42-month period 165 procedures were performed on 100 patients. The study encompasses a unique period of time in this center, as it includes the initial application, and finally, the time when its use became routine. Indications for laser surgery included the treatment of tumors, bleeding, benign strictures, arterial occlusions, and hemorrhoids. Nd:YAG laser was found to be effective in the treatment of these lesions. The overall success rate was 81 per cent. Patients who are poor surgical candidates would especially benefit from this therapeutic alternative.

Aged↗
PubMed1990

Early developmental exposure to benzodiazepine ligands alters brain 31P-NMR spectra in young adult rats.

Alterations in brain high energy phosphate compounds, using 31P-NMR (nuclear magnetic resonance) spectroscopy, were measured in vivo in young adult (3-4 months) rats following prenatal exposure to ligands acting specifically at benzodiazepine (BDZ) binding sites. The exposure induced a decrease in intracellular pH that indicated a predominant interaction of the drugs in utero with central-type BDZ receptor sites. Late gestational exposure to BDZ ligands also induced changes in brain phosphocreatine (PCr) utilization. Exposure to the lowest dose of DZ (1.0 mg/kg) but not the higher dose (2.5 mg/kg) induced a significant change in PCr utilization. Exposure to the central-type BDZ receptor antagonist RO15-1788 alone clearly altered PCr utilization in adult offspring, and DZ (2.5 mg/kg) when administered concurrently was not able to prevent this effect. Though exposure to a peripheral-type ligand (PK11195) had no effect by itself, it converted the effect of the high dose of DZ to that of the low dose. Together, these results indicate an interaction during development between the central and peripheral-type BDZ binding sites on organization and/or regulation of cellular energy metabolism. Normalized ATP levels were not changed by any prenatal treatment indicating adequate buffering of intracellular ATP by phosphocreatine. The dopaminergic antagonist haloperidol did not alter intracellular pH or any index of phosphate metabolism indicating a selective receptor mediated role for BDZ ligands in influences on the long term organization of intracellular phosphate metabolism.

Animals↗
PubMed1990

[Gastroenteritis with eosinophilia caused by Giardia lamblia].

A case of gastroenteritis due to Giardia lamblia with severe dehydration and complicated with arterial thrombosis, accompanied by eosinophilia and increased serum IgE levels, is presented. The relationship between Giardia and eosinophilia and allergic manifestations is discussed as well as its pathogenesis.

Acute Kidney Injury↗
PubMed1989

Double duodenal webs in an adult.

The duodenal web is an unusual cause of gastric outlet obstruction, but one that must be kept in mind in patients with postprandial nausea, vomiting, and epigastric pain. We suggest endoscopic evaluation of the second and third portions of the duodenum in all such patients. At surgery, direct inspection of the duodenal lumen or the confirmation of its patency by passage of a Foley balloon should be routine. If a duodenal web is encountered, the procedure of choice should be duodenostomy with simple excision of the web.

Adult↗
PubMed1987

Long-acting bromocriptine for the acute treatment of large macroprolactinomas.

Six patients with hyperprolactinemia, visual impairment and large macroprolactinoma were treated with a long-acting bromocriptine, in dosage of 50 mg as a single im injection. All patients underwent a full assessment of pituitary prolactin (PRL) secretion before treatment and the studies were repeated about every week during 40 days. Following bromocriptine injection a rapid amelioration of the clinical and visual defects occurred in all patients. Likewise, a significant reduction of the hyperprolactinemia was documented in all six patients and in three of them serum PRL levels reached values as low as 20 ng/ml, and a tumor size reduction was demonstrated by cranial computerized tomography in three of the six cases. No side effects were associated with the administration of bromocriptine. From this study we conclude that the long-acting bromocriptine represents an additional option for the initial management of large prolactinomas in particular when they are associated with severe visual impairment.

Bromocriptine↗
PubMed1987

HLA antigens associated to amoebic abscess of the liver in Mexican mestizos.

Worldwide prevalence of amoebiasis is estimated at 4 x 10(8) cases/year, yet only one of about 300 individuals harbouring Entamoeba histolytica suffers tissue invasion and these cases are mostly concentrated in certain areas of Asia, Africa and Latin America. Patients with amoebic abscess of the liver (AAL) represent only a small fraction of that. These contrasting figures have been tentatively explained on the one hand through variations in sex, immunocompetence, nutritional and other socioeconomic features of the host, and on the other hand through differences in parasite virulence. In order to explore a possible association between the major histocompatibility complex (MHC) and AAL susceptibility, we studied the HLA profile in 31 Mexican mestizos with AAL and compared it to race and socioeconomically matched controls. Mexican mestizo patients with AAL revealed a significant increase in HLA-Bw16 and HLA-DR3 which could suggest an HLA-related susceptibility to liver invasion by E. histolytica.

Abscess↗
PubMed1986

Characterization of surface roughness in titanium dental implants measured with scanning tunnelling microscopy at atmospheric pressure.

Characterization of the surface topography of implant materials is important for understanding tissue response. We have measured, for the first time, the topography of titanium surfaces used in osseointegrated dental implants. Scanning tunnelling microscopy (STM) which provides 3D real space images was used. In addition to clinical samples, electropolished and anodically oxidized surfaces were also measured. Clinical samples are rather inhomogeneous in character showing grooves and steps with a maximum depth of 0.11 micron. Micropores with an average diameter of about 30 nm are also present. Electropolished samples are rather homogeneous and very smooth, showing steps of 1 to 5 nm in height. The measurements were performed under atmospheric conditions at a resolution in the subnanometer range.

Dental Implantation, Endosseous↗
PubMed1986

Gonadotropin-secreting pituitary adenoma with concomitant hypersecretion of testosterone and elevated sperm count. Treatment with LRH agonist.

Hypersecretion of both FSH and LH was demonstrated in a man with pituitary macroadenoma, who also presented elevated levels of blood testosterone and an increased sperm count. The patient underwent transsphenoidal surgery followed immediately by cranial irradiation. Immunocytochemical analysis of the tumour revealed the presence of FSH, LH, TSH and the alpha-subunit. Gel chromatography of the serum on Sephadex G-100 revealed immunoactive FSH, LH and the alpha-subunit which coeluted with the labelled standards of corresponding hormones. Blood levels of both gonadotropins and testosterone remained persistently elevated up to one year following surgical decompression of the tumour and radiotherapy. It was decided to treat this patient with sc administration of 100 micrograms D-Trp6-LRH biweekly. After 20 weeks, LRH-analogue treatment resulted in the reduction of serum FSH and LH levels and a diminishing in tumour size as assessed by computed tomography scan of the pituitary. This report shows that in a patient with clinically and biochemically documented gonadotropin-secreting adenoma, inducing a state of persistent gonadal hyperfunction, pituitary surgery and cranial irradiation failed to normalize the biochemical abnormality; however, therapy with D-Trp6-LRH agonist induced clinical, biochemical and radiologic improvement.

Adenoma↗