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Biomedical subjects

J Carra

Publications and source records attributed to J Carra.

13 recordsLinked to original sources
PubMed2005

Effect of inspiratory threshold loading on ventilatory kinetics during constant-load exercise.

Humoral factors play an important role in the control of exercise hyperpnea. The role of neuromechanical ventilatory factors, however, is still being investigated. We tested the hypothesis that the afferents of the thoracopulmonary system, and consequently of the neuromechanical ventilatory loop, have an influence on the kinetics of oxygen consumption (VO2), carbon dioxide output (VCO2), and ventilation (VE) during moderate intensity exercise. We did this by comparing the ventilatory time constants (tau) of exercise with and without an inspiratory load. Fourteen healthy, trained men (age 22.6 +/- 3.2 yr) performed a continuous incremental cycle exercise test to determine maximal oxygen uptake (VO2max = 55.2 +/- 5.8 ml x min(-1) x kg(-1)). On another day, after unloaded warm-up they performed randomized constant-load tests at 40% of their VO2max for 8 min, one with and the other without an inspiratory threshold load of 15 cmH2O. Ventilatory variables were obtained breath by breath. Phase 2 ventilatory kinetics (VO2, VCO2, and VE) could be described in all cases by a monoexponential function. The bootstrap method revealed small coefficients of variation for the model parameters, indicating an accurate determination for all parameters. Paired Student's t-tests showed that the addition of the inspiratory resistance significantly increased the tau during phase 2 of VO2 (43.1 +/- 8.6 vs. 60.9 +/- 14.1 s; P < 0.001), VCO2 (60.3 +/- 17.6 vs. 84.5 +/- 18.1 s; P < 0.001) and VE (59.4 +/- 16.1 vs. 85.9 +/- 17.1 s; P < 0.001). The average rise in tau was 41.3% for VO2, 40.1% for VCO2, and 44.6% for VE. The tau changes indicated that neuromechanical ventilatory factors play a role in the ventilatory response to moderate exercise.

Adult↗
PubMed2003

Addition of inspiratory resistance increases the amplitude of the slow component of O2 uptake kinetics.

The contribution of respiratory muscle work to the development of the O(2) consumption (Vo(2)) slow component is a point of controversy because it has been shown that the increased ventilation in hypoxia is not associated with a concomitant increase in Vo(2) slow component. The first purpose of this study was thus to test the hypothesis of a direct relationship between respiratory muscle work and Vo(2) slow component by manipulating inspiratory resistance. Because the conditions for a Vo(2) slow component specific to respiratory muscle can be reached during intense exercise, the second purpose was to determine whether respiratory muscles behave like limb muscles during heavy exercise. Ten trained subjects performed two 8-min constant-load heavy cycling exercises with and without a threshold valve in random order. Vo(2) was measured breath by breath by using a fast gas exchange analyzer, and the Vo(2) response was modeled after removal of the cardiodynamic phase by using two monoexponential functions. As anticipated, when total work was slightly increased with loaded inspiratory resistance, slight increases in base Vo(2), the primary phase amplitude, and peak Vo(2) were noted (14.2%, P < 0.01; 3.5%, P > 0.05; and 8.3%, P < 0.01, respectively). The bootstrap method revealed small coefficients of variation for the model parameter, including the slow-component amplitude and delay (15 and 19%, respectively), indicating an accurate determination for this critical parameter. The amplitude of the Vo(2) slow component displayed a 27% increase from 8.1 +/- 3.6 to 10.3 +/- 3.4 ml. min(-1). kg(-1) (P < 0.01) with the addition of inspiratory resistance. Taken together, this increase and the lack of any differences in minute volume and ventilatory parameters between the two experimental conditions suggest the occurrence of a Vo(2) slow component specific to the respiratory muscles in loaded condition.

Adult↗
PubMed2000

Effects of acute ingestion of salbutamol during submaximal exercise.

To assess the eventual effects of acute oral salbutamol intake on performance and metabolism during submaximal exercise, nine healthy volunteers completed two cycling trials at a power corresponding to 80-85% VO2max, after either placebo (Pla) or salbutamol (Sal, 6 mg) treatment, according to a double-blind randomized protocol. Blood samples were collected both at rest and during exercise (5 min-, 10 min-, 15 min-exhaustion) for C-peptide, FFA, lactate and blood glucose measurements. Cycling performance was significantly improved in the Sal vs. Pla trials (p < 0.05). After Sal intake, resting C-peptide, lactate, FFA and blood glucose values were higher whereas exercise lactate and free fatty acid concentrations were greater during and at the conclusion of the exercise period (p < 0.05). These results suggest that acute salbutamol ingestion improved performance during submaximal exercise probably through an enhancement of the overall contribution to energy production from both aerobic and anaerobic metabolisms.

Administration, Oral↗
PubMed1989

Sjogren's syndrome. Its contribution to neuropsychiatric syndrome in patients with primary biliary cirrhosis.

The neuropsychiatric status of patients with primary biliary cirrhosis (PBC) was contrasted to that of patients with PBC and accompanying Sjogren's syndrome and to a matched group of normal controls. The subjects with PBC + Sjogren's syndrome had a more profound impairment on a battery of psychometric tests than did the subjects with PBC alone. In addition, they more frequently met the criteria for a psychiatric diagnosis of anxiety disorder than did those with PBC alone.

Anxiety Disorders↗
PubMed1989

Midazolam versus diazepam for combined esophogastroduodenoscopy and colonoscopy.

This study compares the effects of two different benzodiazepines used for conscious sedation during combined upper gastrointestinal endoscopy (EGD) and colonoscopy. Subjects were assessed for their degree of analgesia and amnesia for the procedure, prior experience with endoscopy, and willingness to undergo another similar procedure should such be necessary. The patients were randomized single blind to receive either midazolam or diazepam for their preprocedure sedation. The amount of preprocedure sedation utilized was determined by titration of the dose to achieve slurring of speech. Prior to receiving either agent, the subjects were shown a standard card containing pictures of 10 common objects, were asked to name and remember them, and were told they would be "quizzed" (at 30 min and 24 hr) after being sedated for their recollection as to the objects pictured on the card. Each subject filled out a questionnaire addressing their perceived discomfort during the endoscopic procedure and their memory of the procedure 24 hr after the procedure. Sixty-three percent of the midazolam-sedated subjects reported total amnesia for their colonoscopy vs 20% of diazepam-sedated patients (P less than 0.001). Fifty-three percent of midazolam-sedated patients reported total amnesia of their upper gastrointestinal endoscopy vs only 23% of diazepam-sedated subjects (P less than 0.05). The midazolam-sedated subjects reported experiencing less pain with both upper gastrointestinal endoscopy (P less than 0.05) and colonoscopy (P less than 0.001) than did the diazepam-sedated group. Most importantly, the midazolam group was more willing to undergo another similar endoscopic procedure should they be asked to do so by their physician (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Impact of cirrhosis on the neuropsychological test performance of alcoholics.

Alcoholics and nonalcoholics with biopsy-proven cirrhosis were compared to each other and to a normal control group on a comprehensive battery of neuropsychological tests. No systematic differences were found between the two liver disease groups. These results indicate that a history of alcoholism does not substantially contribute to the manifest neuropsychological deficits beyond that due to a coexistent hepatic encephalopathy.

Adult↗
PubMed1987

Inflammatory bowel disease: psychiatric status of patients before and after disease onset.

Compared to normal controls, individuals with Crohn's Disease manifest an increased prevalence of anxiety, depression and panic disorder occurring at any time in their life. Only panic disorder had an excess prevalence in Crohn's disease relative to community dwelling normals prior to the time of disease onset. Individuals with ulcerative colitis did not demonstrate an increased prevalence of psychiatric disorder before or after disease onset. The results suggest that there is a higher prevalence of psychiatric disorder in patients with Crohn's Disease relative to the normal population and that a small but significant percentage of individuals with Crohn's Disease may have a psychiatric disturbance which predates their medical illness.

Adult↗
PubMed1987

Memory impairments concomitant with nonalcoholic cirrhosis.

A battery of memory tests was administered to a group of patients with nonalcoholic cirrhosis and to a group of normals. Deficits observed in the former group indicate that there are detectable neuropsychological impairments on measures of higher cognitive functioning in persons who do not otherwise exhibit overt signs or symptoms of hepatic encephalopathy. These findings extend the range of impairments that have been documented to be present as part of the neuropsychiatric syndrome of portal-systemic encephalopathy.

Adult↗
PubMed1987

Sequential concept formation capacity in subclinical (latent) portal-systemic encephalopathy.

A card sorting task measuring sequential concept formation capacity was administered to a group of patients with nonalcoholic cirrhosis and to a group of normal controls. Hepatic disease subjects did not differ from normal controls in abstraction ability as measured in this study, suggesting that not all higher cognitive functions are impaired in persons with subclinical PSE.

Adult↗
PubMed1986

Perceptual field dependency: predisposing trait or consequence of alcoholism?

Perceptual field dependency often has been reported in alcoholics and frequently implicated as a predisposing trait in alcoholism. Comparing sons of alcoholics who are at high risk for alcoholism to sons of depressed fathers and control fathers (nonalcoholics without history of depression) revealed, however, no differences on the rod and frame test. These results do not support the hypothesis that field dependency is a risk factor in alcoholism.

Adolescent↗