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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
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↗
PubMed1984

Selenium deficiency in cattle associated with Heinz bodies and anemia.

Cattle grazing St. Augustine grass growing on peaty muck soils in the Florida Everglades developed anemia associated with the presence of Heinz bodies and suboptimal concentrations of selenium in blood. Selenium supplementation corrected the anemia, prevented Heinz body formation, increased the body weight of cows and calves, and elevated blood selenium. This may be the first recorded example of widespread anemia in a population due to selenium deficiency.

Anemia, Hemolytic↗
PubMed1984

Traumatic myocardial dysfunction.

Traumatic myocardial dysfunction is a frequently unsuspected, undiagnosed contributor to deaths from trauma. Electrocardiography, serum enzymes, and radionuclide myocardial scans are insensitive indicators of cardiac injury following blunt chest trauma. First-pass biventricular radionuclide angiography can accurately determine right and left ventricular ejection fractions and assess left ventricular segmental wall motion. Since August, 1980, we have evaluated 74 consecutive patients with blunt chest and multisystem trauma. Electrocardiograms and measurements of the myocardial band isoenzyme of creatine kinase were obtained at admission and repeated at 24 hour intervals for 3 days. Radionuclide angiography was performed 24 to 48 hours after admission. The electrocardiogram was abnormal in 21 patients (28%), levels of creatine kinase isoenzyme were elevated in six, and radionuclide angiographic abnormalities were present in 55 patients (74%). Electrocardiographic abnormalities correlated anatomically with angiographic abnormalities in 16 patients (76%). On follow-up radionuclide angiography, abnormalities had disappeared in nine of 12 patients restudied at 3 weeks. This study documents that the electrocardiogram and creatine kinase isoenzyme elevations are static, insensitive indicators of traumatic myocardial dysfunction. Radionuclide angiography with studies of left ventricular segmental wall motion demonstrate that traumatic myocardial dysfunction, although sometimes transitory, is a dynamic phenomenon that is more common than previously suspected. First-pass radionuclide angiography and wall motion studies are practical and valuable adjuncts to the management of the injured patient.

Adult↗
PubMed1983

Myocardial dysfunction following blunt chest trauma.

We prospectively studied 35 patients with blunt chest trauma using ECG multi-gated and first-pass nuclear angiography. Radionuclide angiography (RNA) is a sensitive test of myocardial function demonstrating right and left ventricular ejection fractions. First-pass angiography, in addition, shows left ventricular segmental wall motion, a qualitative as well as anatomic indicator of left ventricular function. We saw RNA abnormalities in 26 patients (74.2%). Eight patients (22.8%) had ECG abnormalities, and these findings correlated with RNA, suggesting that this technique is a very sensitive indicator of myocardial dysfunction following trauma. These studies warrant further experimental and clinical evaluations to determine the cause, significance, and long-term prognosis of posttraumatic myocardial dysfunction.

Adult↗
PubMed1983

A new button for retention suture fixation.

A button that may be snapped on and off the end of a retention suture has been described. It allows the tension on the suture to be adjusted easily, increases patient comfort, and avoids circumferential compression of the wound.

Abdominal Muscles↗
PubMed1983

Effect of maternal nutritional status on immunological substances in human colostrum and milk.

Substances in colostrum and breast milk confer significant disease resistance to the breast-fed infant. The influence of maternal nutritional status on both immunological and nonimmunological milk factors was studied in a group of 23 Colombian women during the first 2 months of lactation. Maternal malnutrition was characterized by significantly lower weight/height ratio, creatinine/height index, total serum proteins, serum albumin, and serum IgG and IgA. The colostrum of malnourished mothers contained only one-third the normal concentration of immunoglobulin G and less than half the normal level of albumin. Significant reductions in colostrum levels of IgA and the fourth component of complement (C4) were also observed in the malnourished group. No differences were observed in colostral concentrations of lysozyme, C3 complement, or IgM. Titers of antibody in milk directed against respiratory syncytial virus were not influenced by maternal nutritional status. The differences noted above tended to disappear in mature milk, concomitant with improvement in the nutritional status of malnourished mothers during the first several weeks postpartum. We conclude that the protective qualities of colostrum and milk may be significantly influenced by maternal nutritional status.

Adult↗
PubMed1983

Effect of healing on small internal diameter arterial graft compliance.

Porosity is an essential component for long term function of small internal diameter synthetic vascular prostheses. Theoretically, porosity is required for healing by providing a scaffold for ingrowth of periprosthetic tissues. Porosity may be required for transfer of fluids and ions in prostheses even if tissue ingrowth does not occur. Increased permeability of vascular grafts has been shown to enhance tissue incorporation. Implants with pore sizes greater than 10 microns but less than 45 microns become ingrown with fibrohistiocytic tissue and capillaries. Implants with pore sizes greater than 45 microns are ingrown with organized fibrous tissue and minimal histiocytic response. The phenomenon of differential ingrowth may have important functional significance. Prostheses which heal with organized fibrous tissue have the potential for long term contracture, strangulation of vascularity and calcification. Fibrohistiocytic tissue has low mechanical strength and does not appear to contract or calcify. Elastomeric microporous vascular prostheses which are minimally ingrown or ingrown with fibrohistiocytic tissue maintain compliance after months of implantation. This study was designated to determine the effects of healing on the compliance of small internal diameter vascular replacements and to correlate the compliance to patency rates.

Animals↗