Biomedical subjects

S Cardin

Publications and source records attributed to S Cardin.

10 recordsLinked to original sources

PubMed1992

Hepatic vagotomy does not alter plasma insulin response to a low dose injection of glucose.

It has been reported that insulin concentration is altered by a hepatic vagotomy following intraperitoneal glucose injection (0.3 g/kg) resulting in supraphysiological blood glucose concentrations. On the other hand, neural activity of the hepatic vagus nerve has been shown to be substantially reduced by lower doses (0.05 g/kg intraportal; 0.1 g/kg intravenous). The present study was conducted in order to examine the role of the hepatic vagus nerve in insulin response after intraperitoneal injections of 0.1 and 0.3 g/kg of glucose. Measurements were made 5 days after section of this branch. In a first experiment, arterial glucose and insulin concentrations were not affected by the hepatic vagotomy following injections of either 0.1 or 0.3 g/kg of glucose. The same finding was also found in a second experiment in which portal glucose and insulin levels were measured after injection of 0.1 g/kg of glucose. These results suggest that large changes in neural activity are needed for the hepatic vagus nerve to influence the insulin response.

Animals↗

PubMed1992

Effects of exercise training on insulin response to intravenous glucose in pubertal rats.

This study was undertaken to evaluate the effects of exercise training on glucose tolerance and glucose-stimulated insulin response (GSIR) in 55- and 90-day-old peripubertal female rats. Intravenous glucose tolerance tests (0.5 g/kg) were done in: 1) 90-day-old rats exercised in swimming sessions for either 5 or 10 weeks and evaluated 48 h after the last exercise bout; 2) 55-day-old rats exercised for 5 weeks and evaluated either 24 h or 48 h after the last exercise bout and; 3) unexercised 55- and 90-day-old rats. The total area under the GSIR curve was suppressed in 55- and 90-day-old rats exercised since the age of 21 days. However, this decrease was observed 48 and only 24 h after the last exercise bout in the 90- and 55-day-old rats respectively. Exercise did not affect the GSIR curve for the 90-day-old rats subjected to 5 weeks of exercise training (started at 55 days of age) when evaluated 48 h after the last exercise bout. Nor did one single bout of swimming exercise (2 h) in the last 24 h affect the GSIR in unexercised 55-day-old rats. These results suggest that the shorter duration of the residual effects of exercise in the younger rats (55 days) was related to the shorter length of the training programme. Body weight was not significantly reduced with exercise in 55-day-old rats, whereas the same amount of exercise in 90-day-old rats caused body weight reduction of approximately 35 g (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

Combined effect of 2-deoxy-D-glucose and exercise on plasma catecholamine response.

2-Deoxy-D-glucose (2-DG) is a nonmetabolizable analogue of glucose that, by competitive inhibition of glucose utilization, produces a central neuroglucopenia and a peripheral hyperglycemia. This glucopenic agent was used to gain more insight into the combined effects of central glucopenia and exercise on plasma catecholamine response. This was carried out by comparing one group of exercising (26 m/min, 0% grade) rats injected with 2-DG (2-DG-EX; 250 mg/kg iv) with two control groups: one group of exercising rats injected with a saline solution (SAL-EX) and one group of resting rats injected with 2-DG (2-DG-RE). Significant (P less than 0.05) increases in blood glucose levels were observed 10 min after administration of 2-DG (7.2-13.8 and 7.3-12.4 mmol/l in 2-DG-EX and 2-DG-RE groups, respectively). These elevated blood glucose levels were maintained throughout the experiment in the 2-DG-RE condition but decreased in 2-DG-EX rats to levels observed in the SAL-EX group after 45 min of running (13.8-8.0 mmol/l). The combination of 2-DG-induced neuroglucopenia and exercise resulted in an additive response of norepinephrine (0.59 vs. 0.34 and 0.34 ng/ml; t = 12 min) and an amplified epinephrine response (1.4 vs. 0.37 and 0.31 ng/ml; t = 12 min) compared with the responses to each stimulus alone (2-DG-EX vs. 2-DG-RE and SAL-EX, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

Effect of physical training on insulin response to intravenous glucose in male peripubertal rats.

This study was undertaken to evaluate the effects of regular endurance-type exercise (i.e., swimming) on glucose tolerance and glucose-stimulated insulin response (GSIR) in 55- and 90-day-old peripubertal male rats. Intravenous glucose tolerance tests (0.5 g/kg) were done in four groups of male Sprague-Dawley rats: two groups of trained (TR; 55- and 90-day-old) and two groups of age- and weight-matched untrained (UNTR) rats. The UNTR rats were subjected to a continuous food restriction to maintain body weights equal to those of the TR rats. Rats were received in our laboratory after weaning at 21 days of age and were evaluated 48 h after the last exercise bout. No significant differences in body weights were found between TR and UNTR rats, at the age of either 55 or 90 days. A significant (P < 0.01) decrease in the mean integrated area under the glucose and insulin curves was observed in TR compared with UNTR groups in 55- as well as 90-day-old rats. These results indicate that exercise training in male rats improves the glucose tolerance and GSIR before and during puberty (21-90 days) independently of a reduction in body weight gain.

Animals↗

PubMed1992

Use of patient care extenders in critical care nursing.

This article explores the implementation and use of patient care extenders in two critical care units. Experimentation and diversity in changing the care-delivery system were the forces motivating the management team to redesign the existing nursing care-delivery system. The impetuses for the change process were the use of the role of the registered nurse and cost containment. Two case studies will illustrate from a practical perspective how the change occurred. Although the same nurse manager was responsible administratively for the two units, the patient care extender models were implemented differently. This was based on the conviction that each unit is unique with regard to patients and staff needs. The first case study occurred in an 18-bed cardiac telemetry unit in which the patient extender care model was integrated with direct patient care activities of the unit. In the second case study, which occurred in a ten-bed cardiac care unit, the patient care extender was integrated with indirect patient care activities. The approach to this article is practical, and it is intended for units that may be dealing with these issues in these changing times in health care.

Humans↗

PubMed1992

Need for information. Interventions for practice.

Information is an important need of families of critically ill patients. Meeting this need requires a multidisciplinary approach and an environment that values the delivery of humanistic care. Critical care nurses require special skills in assessment, planning, intervention, and evaluation to effectively meet the information needs of families. Research is available to guide nurses in meeting the family's need for information.

Critical Illness↗

PubMed1991

Effects of supramaximal exercise on blood glucose levels during a subsequent exercise.

The purpose of the present investigation was to examine the effects of hyperglycemia induced by supramaximal exercise on blood glucose homeostasis during submaximal exercise following immediately after. Six men were subjected to three experimental situations; in two of these situations, 3 min of high-intensity exercise (corresponding to 112, SD 1% VO2max) was immediately followed by either a 60-min period of submaximal exercise (68, SD 2% VO2max) or a 60-min resting period. In the third situation, subjects performed a 63-min period of submaximal exercise only. There were no significant differences between the heart rates, oxygen uptakes, and respiratory exchange ratios during the two submaximal exercise bouts (greater than 15 min) whether or not preceded by supramaximal exercise. The supramaximal exercise was associated within 10 min of the start increases (P less than 0.05) in blood glucose, insulin, and lactate concentrations. This hyperglycemia was more pronounced when subjects continued to exercise submaximally than when they rested (at 7.5 min; P less than 0.05). There was a more rapid return to normal exercise blood glucose and insulin values during submaximal exercise compared with rest. The data show that the hyperinsulinemia following supramaximal exercise is corrected in between 10-30 min during submaximal exercise following immediately, suggesting that this exercise combination does not lead to premature hypoglycemia.

Adult↗

PubMed1991

Effect of prolonged exercise on insulin level in the portal and peripheral venous circulation in rats.

The purpose of the present study was to compare the plasma insulin levels in portal and peripheral veins in rats submitted to a prolonged exercise to exhaustion (mean +/- SE: 67 +/- 7 min). Plasma insulin levels were reduced significantly (p less than 0.01) during exercise in both the portal and peripheral venous circulation. The reduction was, however, more pronounced in the portal than in the peripheral vein (mean: -113 vs -64 and -162 vs -88 pmol.l-1 after 30 and 45 min of exercise, respectively), indicating that exercise reduced not only insulin secretion but also its removal. Accordingly, no significant differences were found for the portal/peripheral ratio of insulin at rest and during the first 45 min of exercise (1.86 +/- 0.2, 1.76 +/- 0.1, and 1.57 +/- 0.2 at rest, and after 30 and 45 min of exercise, respectively). This suggests that insulin removal during exercise is regulated in proportion to portal insulin concentrations.

Analysis of Variance↗

PubMed1991

Effect of hepatic vagotomy on hormonal response to exercise in gluconeogenesis-inhibited rats.

The liver, through the afferent pathway of the hepatic vagus nerve, has been reported to influence the hormonal response to exercise in adrenodemedullated rats. The present investigation was designed to evaluate the role played by gluconeogenesis in this hepatic influence. To this end, we studied the effects of a selective hepatic vagotomy on the hormonal response to a 30-min treadmill run (26 m/min, 0% grade) in adrenodemedullated rats injected with 3-mercaptopicolinic acid, a gluconeogenic inhibitor. Hepatic vagotomy was associated with small but significant higher (P less than 0.05) elevations of peripheral blood glucose levels at rest and after exercise. No significant differences were observed between hepatic-vagotomized and sham-operated rats in either resting or exercising levels of liver glycogen, portal glucose, portal and peripheral insulin and glucagon, and peripheral epinephrine and norepinephrine. All hormonal responses, with the exception of epinephrine, were either decreased or increased similarly in the two experimental conditions after exercise. These data indicate that contrary to what has been reported in rats with an intact capacity for gluconeogenesis, hepatic-vagotomized and sham-operated rats with an inhibited gluconeogenesis had similar hormonal responses to exercise. It is concluded that gluconeogenesis plays a role in the afferent neural influence exerted by the liver via the hepatic vagus nerve in the regulation of hormonal response to exercise.

3-Mercaptopropionic Acid↗

PubMed1990

Effects of selective hepatic vagotomy on running endurance in rats.

The liver, through the afferent ways of the vagus hepatic nerve, may influence metabolic adaptations during exercise. This study assesses the functional significance of this hepatic innervation by determining the effect of a selective hepatic vagotomy (HV) on running endurance time during submaximal activity in rats subjected to an overnight 50% food restriction. The time to exhaustion was similar for the groups of HV and sham-operated (SHM) rats [66 +/- 15 vs. 64 +/- 21 (SD) min]. The HV group was associated with higher resting levels (P less than 0.05) of hepatic glycogen and plasma glucose. No significant differences were observed between HV and SHM rats at rest and after exercise for muscle glycogen, free fatty acids, insulin, glucagon, and lactate concentrations. These data indicate that if hepatic glucoreceptors do exist and contribute to the metabolic regulation of exercise, their functional significance is secondary to more important regulatory mechanisms.

Animals↗