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J Rivas

Publications and source records attributed to J Rivas.

64 records · Page 4Linked to original sources
PubMed1977

Evidence pointing to the main role of lysosomes in mitochondrial proteolysis at neutral pH.

Recombination experiments using radioactive mitochondria and mitoplasts, and nonradioactive lysosomes or digitonin-soluble fraction of mitochondria, show equal rates of proteolysis and of inactivation of carbamyl phosphate synthetase; the amount of lysosomal protein was equal in both cases on the basis of N-acetyl-beta-glucosaminidase activity. Therefore, lysosomes seem to be responsible for all the proteolytic activity exhibited by the digitonin soluble fraction of mitochondrial preparations. Since this fraction contains ca. 90% of the proteolytic activity present in mitochondrial preparations, most of the proteolysis can be attributed to lysosomal contamination. These findings and stability characteristics "in vitro" and "in vivo" of some matrix enzymes are presented and discussed in relation to protein turnover.

Acetylglucosaminidase↗
PubMed1977

Acetyl glutamate--a model of signals for intracellular proteolysis.

The proteolysis at neutral pH of mitochondria from liver and brain is more marked in isolated preparations than "in vivo" indicating activation of proteases or inactivation of repressors during isolation. Acetyl glutamate (AG), found in liver mitochondria of ureotelic animals, plays a crucial role as activator of carbamylphosphate synthetase. Since AG levels change under a number of conditions, we checked for an AG deacylase in mitochondria, for otherwise AG must be exported and destroyed by cytosol deacylases. We noted on incubation of mitochondrial extracts with AG an increase in trichloracetic acid-soluble ninhydrin-reacting material but not in acetate liberation, indicating activation of proteases. This was checked with 14C-labelled mitochondria. Under certain conditions AG and other acyl aminoacids stimulate approximately 5 to 20% the proteolysis with rat live and with brain mitochondria.

Animals↗
PubMed1975

[Pulmonary embolism: indication for and results of embolectomy under cardio-pulmonary bypass (author's transl)].

Pulmonary embolectomy under cardio-pulmonary bypass was performed in five patients with massive embolism. Two survived and were ultimately discharged; two died after 40 and 101 days, respectively, of the underlying disease; one patient--operated on under a mistaken diagnosis--was maintained under assisted circulation but died after four days of the underlying disease (cardiac failure). Indications for pulmonary embolectomy under cardiopulmonary bypass should be widened, as it is the only life-saving measure in most cases. After moderately severe pulmonary embolism (lobar embolism) indications for surgical intervention must be individualised from case to case.

Aged↗
PubMedDate not supplied

Equestrian injuries: a five-year review.

A retrospective chart review was conducted to define the demographic and injury patterns of patients presenting to the emergency department (ED). The setting is a rural/small urban tertiary care center with approximately 40,000 visits per year. All patients presenting to the ED from January 1986 through December 1990 with equestrian-related injuries were enrolled in the study. Measurements included age, sex, mechanism of injury, injury or injuries diagnosed, admission to the hospital, morbidity, and mortality. A total of 142 patients met the inclusion criteria. The majority of injuries occurred when the patient fell from a horse. There were also a large number of injuries associated with handling the horse. Most injuries were minor, but 15% required hospital admission. There were no deaths. In conclusion, equestrian activities are associated with a risk of serious injury to both riders and handlers of horses. Education of both the public and primary care physicians should focus on injury prevention.

Adolescent↗
PubMedDate not supplied

[Benign fibrous mesothelioma: report of 8 cases].

Benign fibrous mesothelioma (BFM) is a primary, isolated tumor of the pleura. In 80% of patients the tumor originates in the visceral pleura. BFM is rare and localized malignant mesothelioma, whose prognosis and treatment is significantly different, must be considered as a differential diagnosis. We report 8 cases of BFM excised by thoracotomy. In 6 asymptomatic patients, diagnosis was based on radiological images. One patient with a large tumor suffered dyspnea, acropachia and hypertrophic osteoarthropathy. The last patient experienced long-lasting chest pain even though the tumor was small (3 x 3 x 1 cm). Diagnosis was before thoracotomy in 3 cases, 2 by punch biopsy (tru-cut) and the other by thoracoscopy. The results of pleural fluid analysis were nonspecific in 2 of the 3 cases in which pleural effusion was present. Thoracotomy allowed removal of the entire tumor in all patients.

Aged↗
PubMedDate not supplied

Treatment of high strength distillery wastewater (cherry stillage) by integrated aerobic biological oxidation and ozonation.

The performance of integrated aerobic digestion and ozonation for the treatment of high strength distillery wastewater (i.e., cherry stillage) is reported. Experiments were conducted in laboratory batch systems operating in draw and fill mode. For the biological step, activated sludge from a municipal wastewater treatment facility was used as inoculum, showing a high degree of activity to distillery wastewater. Thus, BOD and COD overall conversions of 95% and 82% were achieved, respectively. However, polyphenol content and absorbance at 254 nm (A(254)) could not be reduced more than 35% and 15%, respectively, by means of single biological oxidation. By considering COD as substrate, the aerobic digestion process followed a Contois' model kinetics, from which the maximum specific growth rate of microorganisms (mu(max)) and the inhibition factor, beta, were then evaluated at different conditions of temperature and pH. In the combined process, the effect of a post-ozonation stage was studied. The main goals achieved by the ozonation step were the removal of polyphenols and A(254). Therefore, ozonation was shown to be an appropriate technology to aid aerobic biological oxidation in the treatment of cherry stillage.

Aerobiosis↗