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Biomedical subjects

R Garcia

Publications and source records attributed to R Garcia.

At least 505 records · Page 28Linked to original sources
PubMed1978

Tonin--angiotensin II system in hypertension.

1. A single intravenous administration of rabbit tonin antiserum into one-kidney one-clip hypertensive rats restored blood pressure to normal in seven out of ten animals. There was little change in blood pressure in two-kidney one-clip hypertensive, uninephrectomized or sham-operated rats. 2. Infusion of tonin in control rats did not modify arterial blood pressure. However, in indomethacin salt-treated rats a marked increase in arterial blood pressure was observed under tonin infusion. 3. Plasma tonin activity was significantly increased in human essential and renovascular hypertension. 4. These findings strongly suggest that tonin is important in the maintenance of high blood pressure. However, other factors (possibly prostaglandins and sodium) have to be modified in order to activate the tonin--angiotensin II system.

Angiotensin II↗
PubMed1978

Comparison of the dried blood on filter paper and serum techniques for the diagnosis of bovine babesiosis utilizing the indirect fluorescent antibody (IFA) test.

A comparison between the techniques of dried blood on filter paper and serum for the diagnosis of babesiosis utilizing the indirect fluorescent antibody (IFA) test was evaluated. Dried blood on filter paper was used as a method to detect B. bigemina and B. argentina antibodies of Colombian cattle under laboratory and field conditions and the technique was compared with the serum of the same animals. A high relationship was found between the results of the dried blood and the serum from calves experimentally infected with Babesia spp. and calves from enzootic hemoparasites-free zones in Colombia. There were no significant differences in the sensitivity and specificity of both techniques. The samples on filter paper could be practical for field use due to their easy management and storage at different temperatures. This indicates that the use of dried blood may be a valuable aid for the epizootiologic studies of Babesia spp. infections in bovines.

Animals↗
PubMed1978

Alphaviruses in Peninusular Malaysia: I. Virus isolations and animal serology.

A survey of the activity of three alphaviruses (Sindbis, getah and chikungunya) in Peninsular Malaysia was conducted between 1962 and 1970. Serum samples were examined from 3,917 vertebrates representing a wide variety of wild and domestic animals throughout the peninsula for hemagglutination-inhibiting and neutralizing antibodies. A total of 548,939 mosquitoes were collected from different habitats, including jungle, rural, suburban and urban areas, and the majority of the females taken were examined for the presence of virus. Two strains of Sindbis virus and one strain of getah virus were isolated from pools of Culex mosquitoes collected in and around domestic animal shelters. Analysis of the serological results indicated that, 1) getah virus is associated principally with large domestic animals, particularly swine, 2) Sindbis virus is associated with large domestic animals and birds, especially domestic ducks, and 3) chikungunya virus, which has not yet been isolated in Malaysia, appeared to be present at a very low level of activity, probably with wild monkeys as the vertebrate hosts.

Animal Population Groups↗
PubMed1977

Effect in vivo of beta-adrenergic stimulation, angiotensin II, dibutyryl cyclic AMP, and theophylline on tonin concentration in rat saliva and submaxillary gland.

Tonin (an enzyme present in rat submaxillary gland and saliva) has previously been shown to be able, unlike renin and reninlike substances, to release angiotensin II either directly by acting on an appropriate substrate or from angiotensin I. The administration of a beta-adrenergic drug, isoproterenol, produces a rise of tonin concentration in saliva without affecting its concentration in the submaxillary gland. Prior administration of a beta blocker, propranolol, partially prevents this effect. The administration of theophylline increases the tonin concentration in both saliva and the submaxillary gland, whereas dibutyryl cyclic AMP increases tonin concentration in the former. These results suggest that beta-adrenergic stimulation enhances both tonin release into the saliva and tonin synthesis in the submaxillary gland, and that these effects might be mediated by cyclic AMP. Infusion of angiotensin II blocked the stimulatory effect of isoproterenol on salivary tonin. 1Sar-8Ile-angiotensin II is both a weak antagonist of angiotensin II in this respect and a strong agonist in terms of blocking the effect of isoproterenol another role mirrored in other physiological mechanisms of derivatives of angiotensin II.

Angiotensin II↗
PubMed1977

Characteristics of psychiatric residency programs and quality of education.

As part of the fiscal year 1975 NIMH review of all psychiatric education grants, 144 basic residency training programs were thoroughly examined. In order to generate hypotheses about factors related to quality, the authors divided these grants into those given high priority rankings, those ranked in the middle, and those disapproved. Faculty and trainee characteristics, aspects of the service system, and organizational, educational, and evaluation factors were strongly related to quality. In general, good programs had a primary theoretical orientation with a tolerance for diversity, were not administratively responsible for community mental health centers but had strong community service ties, and tended to be in university settings. The authors point out the need to determine psychiatry's role vis-à-vis primary care and to develop a clear understanding of the place psychiatry will have in the health and mental health systems.

Delivery of Health Care↗
PubMed1977

Scintiscanning in venous thrombosis of the lower extremities.

Venous scintiscanning was performed once or serially in 252 patients in whom deep vein thrombosis of the lower extremities was suspected, representing a total of 494 limbs examined and 1,266 venous scintiscans performed. When controlled with roentgenologic contrast phlebography, the diagnostic accuracy rate of the isotopic method was 94.4 per cent, which increased up to 98.5 per cent when the thrombotic process was located in a major vein of the upper thigh or pelvis. There were 5.6 per cent false-positive and no false-negative diagnoses. The parameters that we have considered to be the most significant for the accurate interpretation of venous scintiscanning of the lower extremities are mentioned. Venous scintiscanning is a safe, simple and highly reliable method for the study of deep venous thrombotic disease of the lower extremitites.

Collateral Circulation↗
PubMed1976

Evaluation of immunodiagnostic techniques for the detection of human hydatid cyst carriers in field studies.

In a study of 662 sera from a hydatidosis endemic area, the indirect hemagglutination test based on a minimal nonspecificity criterion of positivity and the latex agglutination (LA) test were found to be suitable screening techniques for the detection of sera positive to the arc 5, diagnostic of hydatid infection. The lower nonspecificity of the LA test, its greater simplicity and its excellent correlation with the immunoelectrophoresis test suggest that it is the choice screening technique for use in field surveys or seroepidemiologic studies of hydatid disease. The advantages and limitations of this serologic approach for the detection of human hydatid cyst carriers in field studies are discussed.

Echinococcosis↗
PubMed1976

Epidemic glomerulonephritis in Maracaibo. Evidence for progression to chronicity.

In 1968 an outbreak of 348 cases of acute poststreptococcal glomerulonephritis (AGN) was observed in Maracaibo, Venezuela. During the year, the epidemic had three peaks of incidence. Districts with better sanitation showed a lower incidence of disease than those with less adequate facilities. Endemic cases occur every year. Lowering of serum complement activity was observed in 96% and hypertension in 90% of the patients. The mortality rate in the acute phase during the epidemic was 1.31%. A history of antecedent infection was found in 39% of the cases. 70% of these infections were in the upper respiratory tract. During 1973-74, 120 of the patients (19 adults and 101 children) were reexamined. All but one had been completely asymptomatic. Sixteen patients (13.3%) had one or more of the following abnormalities (group A): low CCr, microscopic hematuria, proteinuria of 1 g/day or more and hypertension. One hundred and four patients (86.7%) were normal by all clinical and laboratory parameters tested (group B). The incidence of persisting disease, as judged by biochemical findings, was significantly higher (P less than .01) in adults (36.7%) than in children (8.9%). Percutaneous renal biopsies from 7 patients of group A, and 8 patients from group B, were studied by light microscopy and immune histology. All biopsies from group A patients had evidence of advanced glomerular disease by light microscopy and by immune histology. Seven biopsies from group B patients were also abnormal showing mild changes with corresponding immunologic findings. Only in one patient was the biopsy completely normal. Our studies indicate that significant numbers of patients progress towards chronicity after epidemic, poststreptococcal AGN. Such progression is more common in adults than in children.

Adolescent↗
PubMed1975

Biochemistry of development in insects. Stereospecific incorporation of fatty acids into triacylglycerols.

1. Previous experiments showed that fatty acids were incorporated into triacylglycerols by homogenates of Ceratitis capitata larvae far more efficiently than by pharate adult homogenates. This metabolic behaviour of both stages of development of the insect has been interpreted throughout the existence of a different acyltransferase activity. To obtain new data on the acyltransferase mechanism, a time-course of the stereospecific incorporation of labelled myristic, palmitic, oleic and linoleic acids into the sn-positions of triacylglycerols has been followed. 2. Studies on the stereospecific incorporation of labelled fatty acids confirmed previous results. Palmitic acid was mainly incorporated into sn-1 and sn-3 positions whereas position 2 exhibited a low incorporation. Myristic acid acylated sn-3 position at a higher rate than it acylated the other sn-positions. Oleic acid was more specifically distributed than palmitic acid and linoleic acid was more efficiently incorporated than the monounsaturated acid. All these data reflect substrate differences in the acyltransferase activity of larval homogenates. Pharate adult homogenates incorporated fatty acids very scarcely and mainly into positions (1 + 3). 3. Kinetics of incorporation of labelled fatty acids into the sn-positions points to a non-random distribution with respect to the major saturated and unsaturated fatty acids in triacylglycerols of larvae of Ceratitis capitata.

Animals↗