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Biomedical subjects

A Rives

Publications and source records attributed to A Rives.

At least 19 recordsLinked to original sources
PubMed1998

Twenty-four-month oral carcinogenicity study of ebrotidine in rats.

Three groups of Sprague-Dawley CD rats (males and females) were initially administered p.o. with ebrotidine, a novel H2-receptor antagonist, mixed with the diet, at 50, 200, and 500 mg/kg/d, respectively. Two concurrent control groups of animals were used. After 13 months, initial 200 mg/kg was lowered to 150 mg/kg, and a new group was administered with 300 mg/kg, due to the body weight reduction observed in the top dose group. After 24 months, survivors were killed and necropsied, and a histopathological study was performed. The frequencies of the different tumour types that were found were not raised due to the treatment. Lower frequencies of some types of pituitary and mammary gland tumours, in the groups treated with the higher doses, were the only statistically significant changes. Among the non-neoplastic effects, a lower body weight increment and food consumption (500 and 300 mg/kg, both sexes), lower survival (500 mg/kg, males), presence of lipoid pneumonia (500 mg/kg, only in males, and 300 mg/kg, both sexes), and lithiasis in urinary system (500 mg/kg) were observed. No changes in gastric mucosa (the main target organ) were attributable to ebrotidine. Regarding the non-neoplastic effects, 150 mg/kg was the no observed adverse effect level. According to the previous results of the carcinogenicity study in mice, conjointly with those of the study in rats reported here, there is no evidence of carcinogenic risk either in males or in females in these species.

Animals↗
PubMed1997

Carcinogenicity studies on ebrotidine.

The results from two carcinogenicity studies on ebrotidine (N-[2-(E)-[[2-[[[2-[(diaminomethylene)amino]-4-thiazolyl] methyl]thio]ethyl]amino]methylene]-4-bromo-benzenesulfonamide, CAS 100981-43-9, FI-3542) conducted in mice and rats are reported. Oral doses of 50, 200 and 500 mg/kg were administered to mice for 18 months and 50, 200 (150), 300 and 500 mg/kg were administered to rats for 24 months. The study design was prepared according to EEC guidelines, and the recommendations by the International Agency for Research on Cancer were used for the statistical analysis of data. Weekly palpations were made along the course of studies and general parameters were monitored. The only effects attributed to ebrotidine administration were a slight decrease in the survival rate of female mice given the 500 mg/kg dose and a lower weight gain in rats of both sexes. The histopathological data revealed that lipoid pneumonia and kidney calculi are more frequent in rats treated with doses of 500 and 300 mg/kg. No increment in the spontaneous occurrence of tumours or significant presence of tumours in treated animals differing from that in control animals was observed, and a decrease in the time required for their onset that could be related to ebrotidine was not observed either. There were no differences in hyperplastic and/or dysplastic changes between treated and control animals. Therefore, it is deduced that ebrotidine does not induce neoplastic or preneoplastic effects in rats or mice even at doses of 500 mg/kg, at which some general toxicity effects are seen.

Animals↗
PubMed1993

[A single bone metastasis as the initial manifestation of an undifferentiated bladder carcinoma].

The spread of Vesical Neoplasia occurs frequently through local or regional extension. Its systemic dissemination happens frequently in advanced phases but it is exceptional as initial manifestation. The case of an undifferentiated vesical carcinoma is described, its presentation was as a big size osteolytic lesion on the sacrum. Local manifestations of the tumor appeared later. The study performed both in bones as well as in the vesical mucosa showed an undifferentiated adenocarcinoma. The great resemblance and histological and immunohistochemical concordances of both biopsies confirmed that it was a primary vesical neoplasia with a metastasis in sacrum. The specific clinical evolution of this tumor is discussed which is probably related with the fact that it is an undifferentiated carcinoma.

Aged↗
PubMed1991

Adult type of leukodystrophy. Krabbe's disease?

A 24-year-old man developed progressive dementia in seven years. The patient suffered a severe bronchopneumonia and eventually died few days later. Brain coronal sections showed a soft gray-brownish discoloration of white matter of centrum ovale but the subcortical arcuate fibers and the interne capsule were preserved. Microscopically, the white matter showed marked loss of myelin and oligodendrocytes, abundant hypertrophic astrocytes and numerous "globoid cells". The latter showed strong positivity in immunostains for a mouse monoclonal antigalactocerebroside antibody. The presence of these cells in the brain white matter might be the morphological basis to classify the present case as one of Krabbe's Leukodystrophy.

Adult↗
PubMed1987

A two-generation reproduction-fertility study of cyanamide in the rat.

A two-generation reproduction-fertility study of cyanamide in the rat has been carried out. After oral administration of 2, 7 and 25 mg/kg/day of the drug, relevant changes have been noted at the highest dose level. Decrease in dam weight gain, in number of corpora lutea, in number of implantations and in number of neonates have been observed in rats of the Fo generation after treatment with 25 mg/kg/day. This group showed a reduced fertility rate and decreases in the weight of several reproductive organs male rats. In contrast to the findings noted in the Fo generation, changes related to cyanamide treatment have not been observed in the F1 generation. Histopathology of these organs has disclosed a low incidence of bilateral testicular atrophy. Decreased fertility rate due to non-specific toxicity associated with a diminished food intake cannot be discarded.

Animals↗
PubMed1987

Prevalence of Sjögren's syndrome in autoimmune diseases.

Investigations were carried out in 122 patients in order to identify features of Sjögren's syndrome (keratoconjunctivitis sicca and xerostomia). There were 78 patients with autoimmune diseases (rheumatoid arthritis 21, scleroderma 16, sicca syndrome 16, primary biliary cirrhosis 14, and other autoimmune disorders 11), 11 patients with chronic liver disease other than primary biliary cirrhosis, and 33 patients with a variety of non-autoimmune conditions or no obvious disease. Keratoconjunctivitis sicca was diagnosed by Schirmer's test and rose bengal staining. The oral component was diagnosed by labial biopsy and salivary scintigraphy. Forty nine patients had a definite Sjögren's syndrome, and 77 patients had the syndrome definitely or probably. Definite Sjögren's syndrome occurred in 62% of patients with rheumatoid arthritis, in 69% of patients with scleroderma, and in 71% of patients with primary biliary cirrhosis. Sjögren's syndrome was not present in any of the patients with non-autoimmune conditions. These results show that in an unselected group of patients with Sjögren's syndrome the prevalence of rheumatoid arthritis (26%), scleroderma (22%), sicca syndrome (22%), and primary biliary cirrhosis (20%) is similar. Also the occurrence of Sjögren's syndrome in primary biliary cirrhosis is even higher than that in rheumatoid arthritis.

Adolescent↗
PubMed1987

Main autopsy findings in bone marrow transplant patients.

The autopsy findings in 24 cases (representing 17 males and seven females) that underwent bone marrow transplantation during the course of disease are reported. The mean age of the patients was 20.0 years, with individual ages ranging from 7 to 40 years. In 23 cases, serious infectious disease occurred. A patient frequently exhibited more than one type of infection. In total, there were seven mycotic, eight cytomegalovirus, and 15 bacterial infections. Twenty-three cases showed striking lung pathology, the most prevalent lesions being infectious diseases and those of diffuse alveolar damage, which was found in ten cases. Gastrointestinal tract pathology of differing types was observed in 13 cases. Necrotizing enterocolitis was observed in three of these cases. Three cases also displayed cholangiolar cholestasis, probably related to their terminal infectious disease. In only two cases could graft-vs-host disease be proved histologically.

Acute Disease↗
PubMed1986

Upper gastrointestinal bleeding caused by gastroduodenal vascular malformations. Incidence, diagnosis, and treatment.

Within a two-year period, 12 patients with upper gastrointestinal bleeding due to gastroduodenal vascular malformations were admitted to a specialized intensive care unit. They represented 2.1% of all admissions for upper gastrointestinal bleeding, and 3.7% of those with severe hemorrhage (greater than or equal to 2 units of blood transfused). Early endoscopy was nondiagnostic during the first bleeding episode in all nine patients with nonhereditary vascular malformations; the diagnosis was eventually made after relapsing hemorrhage by repeat endoscopy in five patients, angiography in two, and histology in another two. These nine patients accounted for 23.6% of all cases of upper gastrointestinal bleeding considered to be of unknown origin after initial work-up. The remaining three patients had Rendu-Osler-Weber disease, and the first endoscopy was diagnostic in all of them. Emergency treatment was required for 11 patients; surgery was undertaken in seven, and transendoscopic therapy (electrocoagulation or endoscopic clipping) in four. There was a 25% mortality rate. No further bleeding has occurred in eight patients after a mean follow-up period of two years. Gastroduodenal vascular malformations are a more frequent cause of upper gastrointestinal bleeding than heretofore recognized, especially in patients whose hemorrhage is deemed to be of unknown origin after an initial work-up. Endoscopy, which may need to be repeated, is the most rewarding diagnostic procedure. Awareness of their possible existence facilitates endoscopic recognition. When available, transendoscopic therapy is a good choice to stop active bleeding from such lesions.

Adolescent↗
PubMed1986

Atherosclerosis of the internal mammary artery. Histopathological analysis and implications on its results in coronary artery bypass graft surgery.

To evaluate internal mammary artery (IMA) atherosclerosis in our population, 38 segments of IMA obtained at the time of coronary surgery and 20 segments of IMA obtained at postmortem studies were histologically studied. Hematoxilin-eosin, Masson trichromic, elastic fibers and reticulin fibers were the stain methods used. A total of 236 sections were studied. Atherosclerosis was graded from 0 to 4 according to Kay and co-workers. Severe disease, with more than 50% luminal narrowing was found in one necropsy case (5%) and in no surgical case. In the surgical group, only one case (2.36%) showed a degree 3 luminal narrowing (between 25% and 50% luminal reduction). The remaining sections were normal or minimally affected. It is concluded that the IMA shows minimal atherosclerotic changes, being considered a protected vessel.

Adult↗