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Biomedical subjects

A Rivas

Publications and source records attributed to A Rivas.

At least 73 records · Page 4Linked to original sources
PubMed1978

Hydrocephalus after posterior fossa operations.

Sixteen patients with hydrocephalus which developed after operations on the posterior fossa were studied by radioisotope ventriculography. The results indicate that postoperative hydrocephalus is of communicating type, and that block of the basal cisterns is always present. Mechanisms involved in its pathogenesis are discussed, and it is felt that pre-existent adhesions in basal cisterns, surgical bleeding and cerebrospinal fluid (CSF) extra-arachnoidal collections are possible causes of the hydrocephalus.

Cerebellar Neoplasms↗
PubMed1976

In vitro degradation of ribosomes.

The cytoplasmic ribosomes from Euglena gracilis var. bacillaris are found to be of two types taking into consideration their stability "in vitro". In the group of unstable ribosomes the large subunit is degraded. The other group apparently does not suffer any degradation under the conditions described. However the RNAs extracted from both types of ribosomes are degraded during sucrose density gradients. The degradation of the largest RNA species has been reported previously, but no comment has been made about the stability of the ribosome itself.

Cell Count↗
PubMedDate not supplied

Twice daily netilmicin therapy in paediatric patients with systemic infections.

This open investigation evaluated twice daily administration of netilmicin in infants and children with systemic infections. Thirty-four patients aged 2-41 months, were enrolled; 28 and 34 were evaluable for efficacy and safety, respectively. Netilmicin was administered intravenously or intramuscularly every 12 h at a dosage of 2.0-4.4 mg/kg (mean 3.5 mg/kg) for 5-15 days (mean 11 days). Throughout the trial, signs and symptoms of infection were evaluated in conjunction with laboratory data to determine patients' clinical response; specimens from appropriate sites were cultured to determine bacteriological response; and laboratory tests were performed to monitor haematopoietic, hepatic and renal functions. Peak and trough serum netilmicin levels were measured during treatment. Clinical responses included complete resolution in 26/28 (93%) patients, improvement in 1/28 (4%) and failure in 1/28 (4%). Bacteriological responses included elimination of 34/36 (94%) pathogens and persistence of 1/36 (3%); response was indeterminate for 1/36 (3%). Peak serum netilmicin levels of 5.1-14.1 micrograms/ml and trough serum netilmicin values of 0.1-1.5 micrograms/ml remained within acceptable ranges during treatment. No clinically significant changes in haematopoietic, hepatic and renal functions were evident during the trial. Untoward reactions were limited to redness and/or induration at the administration site in 4/34 (12%) patients.

Bacteria↗
PubMedDate not supplied

Inadvertent exposure to xenoestrogens in children.

This article reviews previous studies and presents new data on pesticide exposure in order to provide some indications of the extent and significance of childhood exposure to xenoestrogens, including pesticides, epoxy resins, and polycarbonates. After more than four decades of pesticide use, little is known about their adverse effects on health. There is a need to address the potential risks associated with the current contamination of water, soils, and foods in many agricultural areas. In southeastern Spain, along the Mediterranean coast, extensive areas alongside residential zones are devoted to intensive farming in plastic greenhouses, with the use of large amounts of pesticides. Human tissue samples have been investigated for pesticide residues. Samples of fat from children living in farm areas contained a total of 14 pesticides, including lindane, HCH, heptachlor, aldrin, dieldrin, endrin, endosulfan, o,p'-DDE, and o,p'-DDD, among others. Of the 113 samples studied, 43 were positive for one or more pesticides, some of which have estrogenic activity. The number of new substances that mimic the action of endogenous estrogens is increasing rapidly. These endocrine-disrupting chemicals are not restricted to pesticides. Several different compounds used in the food industry, in plasticizers, and in dental restorations are also estrogenic. The few studies that have investigated their effects in humans all indicate that concerns are warranted. If there is indeed an association between zexposure to substances with hormone-disruptive activity and certain disorders of sexual maturation, the incidence of such disorders should be greater in areas where exposure to agents with this activity is high. We used a spatial ecological design to search for variations in orchidopexy rates and to analyze relationships between these differences and geographical variations in exposure to pesticides. Our results are compatible with a hypothetical association between exposure to hormone-disruptive chemicals and the induction of cryptorchidism. Several methodological limitations in the study design make it necessary to evaluate the results with caution. In conclusion, a closer scrutiny is required to determine whether epoxy resins and polycarbonates contribute, together with estrogenic pesticides, to the exposure of human consumers, especially children, to xenoestrogens.

Adipose Tissue↗
PubMedDate not supplied

[Multilocular cystic nephroma. A diagnostic problem].

A multilocular cystic nephroma is described in a female patient diagnosed as having a mucinous cystadenocarcinoma of the left ovary, treated by surgery. It is presented as a mixed mass in the left kidney; image findings were specified with the new image diagnostic methods currently available, ultrasonography and computerized tomography. In the ultrasonographic study the mass is presented as an heterogenous image, with multiple anecogenic areas, separated by more ecogenic bands, situated mainly in the lower pole affecting all the cortical area and occasionally invading renal sinus. In the computerized tomography study a cystic mass is observed, with cysts of a different size that, after administering intravenous iodine, show a density increase in intercystical fibrous tracts. In cases with more complex image presentations, fine needle puncture is recommended, preferably in different areas in the mass in order to rule out the presence of malignant cells.

Aged↗
PubMedDate not supplied

[Chlamydial proctitis in homosexual men].

We present 3 homosexual male patients, with lesions confined to the rectum, produced by chlamydia trachomatis. In the 3 patients the lesions were confined to the first 10 cm from of the anal margin, they were nodular, ulcerated and with stenotic tendency, difficult to differentiate macroscopically from a neoplasm. Multiple biopsy specimens from all patients reported chronic unspecific proctitis. In the 3 patients the presence of chlamydia trachomatis was confirmed by staining with lugol and giemsa from samples obtained by rectal smear, two of them presented simultaneous infection by neisseria gonorrhoeae, all were positive for HBsAg and one for HIV. Symptoms were tenesmus rectal urge, pain, thin feces and mucosanguinolent discharge. Treatment with 100 mg. Doxycycline BID for 21 days resulted in total remission in two patients; one patient with significant clinical improvement needed rectal bougienage.

Adult↗