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Biomedical subjects

J Osorio

Publications and source records attributed to J Osorio.

36 records · Page 2Linked to original sources
PubMed1991

Venezuelan equine encephalomyelitis virus infection in and transmission by the tick Amblyomma cajennense (Arachnida: Ixodidae).

To assess a possible role of ticks as the maintenance host for epizootic strains of Venezuelan equine encephalomyelitis (VEE) virus, laboratory experiments were conducted to determine if ticks could become infected, maintain, and transmit the virus. Larval and nymphal Amblyomma cajennense (F.) and larval Dermacentor nitens Neumann ticks were exposed to epizootic VEE virus (Trinidad donkey strain) by allowing them to feed on viremic guinea pigs (strain 13). In A. cajennense, transstadial transmission was observed from larvae to nymphs and adults. Horizontal viral transmission to a mammalian host was accomplished by nymphs. Infection rates in nymphs and adults were 2% (42/2,750) and 4% (9/244), respectively, afer ingestion of virus as larvae. Virus was detected in A. cajennense adult ticks for up to 171 d after infection in the larval stage. A cajennense, exposed as nymphs, ingested virus but did not become infected (0/164 after 10 d after taking an infective bloodmeal). No virus was detected in D. nitens 7 d after exposure. These findings suggest that A. cajennense potentially could be involved in an interepizootic maintenance cycle of epizootic VEE viral strains.

Animals↗
PubMed1979

Effect of somatostatin on the potentiating action of glucagon, cyclic adenosine monophosphate and theophylline on glucose-induced insulin release.

The effect of glucagon on the inhibition of the insulin response to glucose induced by somatostatin was investigated in humans and in the isolated perfused rat pancreas. Both in vivo and in vitro somatostatin suppressed glucose-induced insulin release. This inhibitory effect of somatostatin was overcome by glucagon. Similar results have been observed in vitro by the infusion of theophylline or cyclic adenosine monophosphate.

Animals↗
PubMed1979

[Effect of octanoic acid on the insulin secretion in response to glucose in vitro (author's transl)].

The effect of octanoic acid (1.5 mM) on insulin secretion in 4.4 and 16.7 mM glucose stimulation has been studied in rat's isolated and perfused pancreas. The absence of octanoic acid does not produce any significant insulin secretion increase in response to 4.4 mM glucose infusion, whereas its presence produces a significant insulinic response of a monophasic nature. Both in the presence and absence of octanoic acid, the 16.7 mM glucose-stimulation produces a biphasic insulin secretion. The octanoic acid enhances both the first and the second phase of insulin secretion. The present results show that octanoic acid clearly potentiates the insulin secretion in response to 4.4 mM and 16.7 mM glucose.

Animals↗
PubMed1977

Stimulation of renin release by prostaglandin E2.

The effect of different doses of prostaglandin E2 on renin secretion in isolated perfused rat kidney has been studied. The infusion of 5 ng/ml of prostaglandin E2 produced a significant rise on renin secretion compared with control group. A dosage increase of prostaglandin E2 (10 and 50 ng/ml) produced an increase in the released renin. From this a correlation between doses and responses can be obtained. The perfusion pressure was slightly--but significantly--modified with the highest dose of prostaglandin (50 ng/ml). The possible pathways of action are dicussed.

Animals↗
PubMed1976

Diurnal variation in blood sugar and serum insulin in response to glucose and/or glucagon in healthy subjects.

The role of insulin secretion in the diurnal variation of glucose tolerance has been investigated. In ten healthy subjects, at 08.00 and at 18.00 after 10 hrs of fasting, a combination test of glucose and glucagon was performed. 1 mg glucagon was injected intravenously 40 min after the intravenous infusion of glucose (0.5 g/kg b.w.). Samples for blood sugar (BS) and serum immunoreactive insulin (IRI) were taken before and 2-5 min following the glucose and glucagon loads, and thereafter at 10 min intervals up to 85 min. In the afternoon test, the mean blood sugar values were higher, the differences in the 20-85 min values being statistically significant: the IRI values were statistically lower after glucose, while after glucagon, the increase of serum IRI was apparently similar in both morning and afternoon tests. However, the insulin/glucose ratio (I/G) was significantly lower at 18.00 at 55-85 men. Corresponding results were obtained in six additional healthy subjects when only glucagon (1 mg i.v.) was injected. In this case also, the mean insulin levels were lower in the afternoon after 5 min, while the BS values during the maximal insulin release (2-30 min) were comparable in both the morning and afternoon tests. In the 40-60 min interval, the BS levels were significantly higher in the afternoon. The existence of a diurnal variation in the blood sugar after intravenous glucose load, as well as after glucagon, seems to be correlated to a simultaneous diurnal variation in the insulin response, suggesting decreased pancreatic beta-cell activity in the afternoon.

Adult↗
PubMed1976

[Kinetics of renin reaction in rat plasma (author's transl)].

Important kinetic aspects of renin reaction were studied in order to evaluate the parameters that regulate the formation rate of angiotensin I. This rate decreased throughout the incubation period of normal rat plasma and it showed a linear increase when plasma was incubated with renin-substrate. When renin was added to normal rat plasma a plateau in the angiotensin I formation rate occurred after 4-6 hours. When plasma samples containing increasing amounts of renin-substrate were incubated, the velocity of their reaction increased in proportion to the renin-substrate concentration. Under these incubation conditions, the reaction between endogenous renin and renin-substrate in normal rat plasma, proved to be a first kinetic order with respect to the substrate.

Angiotensin II↗
PubMed1976

Inhibition of the glucose induced insulin release by somatostatin in the isolated perfused rat pancreas. Action of cyclic AMP, glucagon and glibenclamide.

Insulin release in the perfused isolated rat pancreas was measured after stimulation with 16.5 mM glucose with and without somatostatin (cycle form, 100 ng/ml) in the medium. A complete blockage of the typical biphasic pattern of insulin release ocurred with somatostatin in the medium. Such blockage was abolished when cAMP (2.5 mM) and a 0.5 ml solution of glucagon (1 mg/ml) were continuously perfused for 20-minute periods and for 30-second periods correspondently. It did not take place when glibenclamide (HB-419) was perfused for a 20-minute period at a rate of 10 mug/ml. The results suggest that the adenylcyclase dependent mechanisms of glucose-induced insulin release are involved in the inhibition of the glucose-induced insulin secretion by somatostatin.

Animals↗
PubMed1975

Insulin secretion in the perinatal period of the rat in vivo and in vitro effects of glucose and gibenclamide (HB 419).

During the perinatal period of the rat the effect of glucose and glibenclamide (HB 419) on the secretion of insulin was studied in vivo and in vitro. In the in vitro experiments isolated islets of 21 day old fetal and 5 day old newborn rats were perifused wtih 16.7 mM glucose or 16.7 mM glucose plus 1 mug/ml glibenclamide, while in the in vivo ecperiments glucose, 0.5 g/kg of body weight, or glibenclamide, 0.5 mg/kg of body weight were tested. Glucose elicited a small first phase of insulin release in 21 days old fetal islets, while glucose plus glibenclamide evoked a biphasic pattern. The injection of glibenclamide to the mother lowered the blood sugar in the fetus and increased the fetal serum insulin concentration. In one day old newborn rats glibenclamide stimulated the secretion of insulin after an i.p. injection. Glucose was without effect. Both substances increaseded the serum insulin concentration in five day old newborn animals. Dynamic studies at that age revealed a monophasic response to glucose and a biphasic pattern to glucose plus glibenclamide.

Animals↗
PubMedDate not supplied

[Anesthetic management during removal of a giant intrathoracic mass].

We report the case of a young woman with a giant intrathoracic angiomyolipoma accounting for 10% of her weight and occupying 75% of the right hemithorax and 30% of the left. Before anesthetic induction, an arterial line and a central venous catheter were applied for monitoring; neck and thoracic punctures were avoided. The trachea was intubated with a double lumen tube after provision of sedation and analgesia with remifentanil-midazolam and topical anesthesia of the larynx. A rigid bronchoscope and extracorporeal circulation were available at all times and muscle relaxants were avoided. Ventilation was maintained with pressure support until the mass effect was resolved. The patient was transferred to the intensive care unit, extubated after 24 hours, and discharged 5 days after surgery. We describe the recommendations for perioperative management in cases involving this type of tumor and the complications that can develop. Recent symptoms, diagnostic images, and the results of lung function tests provide information for guiding the anesthetic approach. The obstructive ventilatory compromise caused by a giant mass depends more on location than size. Extracorporeal circulation or rigid bronchoscopy might be needed at any time during surgery.

Adult↗
PubMedDate not supplied

Occlusal contact variation with changes in head position.

Ten healthy young adults were examined for changes in occlusal contacts related to three head positions: supine, sitting, and head forward. The contacts were analyzed using T-Scan special research software, which measured the time moments of the first five occlusal contacts. Time moment is a descriptive term calculated from a formula that considers both spatial (where contacts are) and temporal (when contact occurs) aspects of tooth contact and provides a quantitative basis for comparing the dynamics of tooth contact. Paired head positions were analyzed for differences using Student's t test, and it appears that in healthy young adults, initial tooth contacts are substantially influenced by posture.

Adult↗