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Biomedical subjects

L Gibbons

Publications and source records attributed to L Gibbons.

107 records · Page 6Linked to original sources
PubMed1993

Effect of dietary fish oil supplementation on fever and cytokine production in human volunteers.

The effect of dietary fish oil supplementation on acute phase responses to intramuscular injection of typhoid vaccine, and in vitro cytokine production, was investigated in human volunteers. Half of the subjects supplemented their normal diet with 4.5 g/day of fish oil for 6-8 weeks. Injection of typhoid vaccine in unsupplemented subjects caused an increase in white cell count, resting heart rate, metabolic rate, oxygen consumption, and oral temperature. Fish oil supplementation inhibited the tachycardia and attenuated the maximal increases in oral temperature and metabolic rate following typhoid vaccine. However, interpretation of these latter results were complicated by similarly attenuated responses in saline-injected subjects. The in vitro production of interleukin-1 and interleukin-6 from whole blood was suppressed by fish oil supplementation, however, production of tumor necrosis factor alpha was not significantly altered. Fish oil supplementation may therefore provide a non-pharmacological approach of attenuating several of the responses associated with injury and infection and this may be related to reduced cytokine (IL-1 and IL-6) production.

Journal Article↗
PubMed1993

Patterns of recurrence and survival in AMI patients in Canada.

OBJECTIVE: To describe the patterns of recurrence and survival of patients following their first acute myocardial infarction (AMI). DESIGN: A retrospective follow-up study based on the population of Nova Scotia and Saskatchewan from 1981-85. SUBJECTS: The analyses were performed on patients aged 25 to 75 years (n = 2083) who had been admitted to hospital with their first AMI during 1981 from the provinces of Nova Scotia and Saskatchewan. MAIN RESULTS: The rate of recurrence of AMI was 10% in men and 7% in women, regardless of age. Median time to recurrence was 13 to 15 months in men and seven months in women. After the first AMI, mortality rates were higher in women one week and one month after the initial infarction, reaching statistical significance (only in the 55- to 74-year-old age group)--P < 0.01 and P < 0.02, respectively. Five-year mortality rates were significantly higher in the older age groups (P < 0.01), but were similar in men and women. CONCLUSIONS: Reinfarction occurs more quickly in women, who also appear to be at a higher risk of death during the first month, and especially during the first week, postinfarction.

Adult↗
PubMed1992

Induction of sleep apnoea with negative pressure ventilation in patients with chronic obstructive lung disease.

BACKGROUND: Negative pressure ventilation provides intermittent non-invasive ventilatory assistance for patients with advanced chronic obstructive lung disease. Upper airway obstruction during sleep, a reported complication of the technique, may, however, limit its clinical applicability. METHODS: The effects of nocturnal negative pressure ventilation on ventilation and on indices of sleep quality were investigated in five patients with severe chronic obstructive lung disease (mean (SE) FEV1 31% (3%) predicted) who had completed three months of nightly negative pressure ventilation. Subjects underwent overnight polysomnography on consecutive nights, the first night serving as a control and negative pressure ventilation being provided on the second night. Ventilators were adjusted to result in maximum suppression of the peak phasic electromyogram signal from the diaphragm. RESULTS: Negative pressure ventilation resulted in substantial increases in episodes of obstructive apnoea and hypopnoea (mean (SE)/h 59.3 (19.8) v 3.2 (1.3) on control nights). Most obstructive events, however, were associated with under 3% oxygen desaturation, and the lowest recorded values for overnight oxygen saturation were similar on the two study nights. Negative pressure ventilation was also associated with significant increases in the frequencies of movement arousals and changes in sleep stage. CONCLUSIONS: Negative pressure ventilation applied during sleep to patients with advanced chronic obstructive lung disease may result in the development of recurrent episodes of apnoea and hypopnoea as well as altered sleep quality, which could limit its clinical applicability.

Aged↗
PubMed1990

Aminophylline and human diaphragm strength in vivo.

The transdiaphragmatic pressure (Pdi) twitch response to single shocks from supramaximal bilateral phrenic nerve stimulation was studied before and after acute intravenous infusions of aminophylline [14.9 +/- 3.1 (SD) micrograms/ml] in nine normal subjects. Stimulation was performed with subjects in the sitting position against an occluded airway from end expiration. Baseline gastric pressure and abdominal and rib cage configuration were kept constant. There was no significant difference in peak twitch Pdi from the relaxed diaphragm between control (38.8 +/- 3.3 cmH2O) and aminophylline (40.2 +/- 5.2 cmH2O) experiments. Other twitch characteristics including contraction time, half-relaxation time, and maximum relaxation rate were also unchanged. The Pdi-twitch amplitude at different levels of voluntary Pdi was measured with the twitch occlusion technique, and this relationship was found to be similar under control conditions and after aminophylline. With this technique, maximum Pdi (Pdimax) was calculated as the Pdi at which stimulation would result in no Pdi twitch because all motor units are already maximally activated. No significant change was found in mean calculated Pdimax between control (146.9 +/- 27.0 cmH2O) and aminophylline (149.2 +/- 26.0 cmH2O) experiments. We conclude from this study that the acute administration of aminophylline at therapeutic concentrations does not significantly affect contractility or maximum strength of the normal human diaphragm in vivo.

Adult↗
PubMed1989

The safety of maximal exercise testing.

Previous reports on the safety of exercise testing have been based on surveys from different testing facilities with a variety of testing protocols and patient types. From 1971 through 1987, 71,914 maximal exercise tests conducted in a population with a low prevalence of known coronary heart disease under uniform conditions at a single medical facility resulted in six major cardiac complications including one death. No complications have occurred in the past 10 years in 45,000 maximal tests. The overall cardiac complication rate in men and women is 0.8 complications per 10,000 tests with 95% confidence intervals of 0.3-1.9 complications per 10,000 tests. Maximal exercise testing appears safer than some previously published reports have suggested and seems to be getting safer with time.

Accident Prevention↗
PubMed1989

Effect of nutritional status on exercise performance in patients with chronic obstructive pulmonary disease.

The purpose of our study was to examine the nutritional status of patients with severe chronic obstructive pulmonary disease (COPD) (mean predicted FEV1, 30 +/- 11%) and to explore its relationship to functional capacity. Functional capacity was evaluated by measuring peak oxygen consumption (VO2max) using an incremental cycle ergometry test, a 6-min walk test, self-perceived level of dyspnea, and quality of life. The percentage ideal body weight (%IBW) was less than 90% in 33 of 135 subjects. Triceps skinfold thickness was less than 60% of normal in 19 of 33 of these subjects. Total lymphocyte count was not different between groups, whereas hemoglobin (14.9 versus 15.9 g/dl) and albumin (4.0 versus 4.1 g/dl) were marginally reduced in underweight subjects. Dyspnea and overall quality of life were unaffected by nutritional status. Maximal inspiratory (Pimax) and expiratory mouth pressures (PEmax) were weakly associated with %IBW (R2 = 0.04; p = 01 and R2 = 0.15; p less than 0.01, respectively). The %IBW was a predictor of VO2max (percent predicted) after controlling for FEV1 in regression analysis (partial R2 = 0.08; p less than 0.001). Despite the association of weight status with VO2max, the 6-min walk was not influenced by %IBW. The perceived intensity of exercise as judged by the Borg score was far greater with the bicycle exercise that with the 6-min walk (mean score, 10.6 +/- 1.2 versus 4.6 +/- 1.9). This was supported by the difference in heart rate after these two tests.(ABSTRACT TRUNCATED AT 250 WORDS)

Body Weight↗
PubMed1987

Triple-contrast computed tomography in the evaluation of penetrating posterior abdominal injuries.

Routine exploration of stable patients who have penetrating injuries of the posterior abdomen results in a high rate of unnecessary operation. Prolonged observation, while safe, is expensive and potentially morbid in the event that a retroperitoneal injury has occurred and treatment is delayed. To evaluate these injuries, we have developed and employed a protocol for computed tomographic (CT) scanning of the abdomen employing oral, intravenous, and rectal administration of contrast material to visualize the retroperitoneal contents. Between Jan 1, 1985, and Dec 1, 1986, 40 patients were studied in this manner. In each case, the path of penetration could be determined exactly by tracing the course of air and hematoma through the tissues. All retroperitoneal organs could be evaluated well enough to exclude injuries requiring intervention. The majority of patients showed subcutaneous penetrations only. All six significant intra-abdominal injuries were diagnosed correctly and confirmed at laparotomy. All 34 patients deemed by CT not to have significant injury were observed for 72 hours, and all were discharged uneventfully. Triple-contrast CT appears to be of great value in the triage of penetrating posterior abdominal trauma into operative and nonoperative groups.

Abdominal Injuries↗
PubMed1986

Variation of cooling rate and concentration of dimethyl sulfoxide on rabbit kidney function.

Rabbit kidney function was assessed in vitro after cryoprotection with either 3 or 4 M dimethyl sulfoxide. The introduction and removal of the cryoprotectant was carried out in a stepwise progressive manner and the removal in a stepwise progressive manner with hypertonic mannitol solutions. This in vitro model can be shown to respond to various ischemic-like states resulting in poor or absent function. Active tubular transport can be demonstrated. It has been used by many authors as an intermediate step prior to the ultimate test of reimplant and contralateral nephrectomy. Variations in the rate of cooling at cryoprotection levels of 3 and 4 M dimethyl sulfoxide concentration (Me2SO) were carried out. In general, at 3 M concentration of Me2SO, creatinine clearance, sodium and glucose reabsorption are preserved with a fair degree of success after cooling to -10, -15, and -20 degrees C in our model, when the rate of cooling to these levels is 1.0 degree C/min. When a cooling rate of 0.5 degree C/min is used, renal function is significantly reduced whether the final temperature is -10, -15, or -20 degrees C. Control rabbit kidneys will tolerate 4 M concentration of Me2SO and give fairly good function. When cooled to -15 or -20 degrees C, there is poor function at 0.1 and 0.5 degrees C/min. Fair function is obtained at the rate of 1 degree C/min to -10 degrees C. Therefore, at cryoprotectant levels of 3 and 4 M Me2SO, kidney function as assayed by in vitro perfusion, is better when the cooling rate is 1.0 degree C/min.

Animals↗
PubMed1985

Fetal rat intestinal transplantation: cryopreservation and cyclosporin A.

Successful preservation of small bowel by cryobiologic techniques would increase the feasibility of intestinal transplants. Immunosuppression by Cyclosporin A (CyA) has also increased interest in intestinal transplantation. We have investigated the effect of cryopreservation and immunosuppression in fetal rat intestinal transplantation. Segments of fetal bowel implanted isogeneically into the paravertebral gutter of young rats were found to grow in a high percentage of animals (53% to 100%). Segments frozen to -20 degrees C or -40 degrees C at two rates of cooling, grew isogeneically (50% to 89%), demonstrating the feasibility of cryopreservation. Histologic examination of this bowel showed preservation of structure. When these segments were cooled and implanted allogeneically, no immunosuppressive effect was found. Segments protected by daily CyA administration grew. No synergistic effect was seen by associating CyA and cryopreservation. These experiments suggest the possibility of creating fetal small bowel long-term banking.

Animals↗
PubMed1979

[The future of nursing in Latin America].

The authors take up the subject with a retrospective review of the concepts of economic and social development, the health policy that has emerged in the last 25 years, and the salient characteristics of health practice and the training of nursing personnel. They interpret development in the health field and various approaches to the extension of the health services coverage that have been taken in the countries of Latin America through implementation of the strategies of primary care and community participation. Finally, they present several considerations on the future of nursing, with emphasis on a comprehensive view of the profession as an occupation and a social practice, after which they formulate a series of propositions that can serve as a basis for training of the nursing personnel that will be needed to serve society adequately.

Education, Nursing↗
PubMed1977

The important role of fitness determination and stress testing in predicting coronary incidence.

The question of whether there is some effect of status of cardiorespiratory fitness and exercise ECG abnormalities on occurrence of CHD other than their effect on the risk factors of serum cholesterol, blood pressure, glucose, and smoking seems to have been answered in the affirmative by this study. The relative prognostic importance of the measures considered here, the role of exercise, and the interrelationships between fitness, exercise, other risk factors, and CHD provide many interesting hypotheses for continued study. A future investigation will involve a large prospective study in which the risk function to be derived would include stress ECG and treadmill performance as predictor variables. The retrospective approach reported in this paper had certain limitations. It did, however, permit demonstration of new results because, essentially for the first time, all of the important risk factors are measured in the study population and can be evaluated simultaneously.

Adult↗
PubMedDate not supplied

The impact of the decreased prevalence of smoking in Canada.

Using data on the prevalence of smoking among different age and gender groups, we estimated the impact of the prevalence of smoking on the present and future mortality of Canadians. In 1989, the life expectancy of male smokers at the age of 45 was 7 years less than non-smokers, among female smokers life expectancy was 4 years less than non-smokers. The total number of smoking-attributable deaths from all causes was estimated for every decade from 1969 to 2019. A decrease in smoking prevalence from 1989 levels to 10% overall in 1999 would result in 15,000 and 6,000 fewer smoking-attributable deaths among women and men, respectively. Continuing the existing pattern of smoking among men and women will result in an increase in the total number of smoking-attributable deaths among women and an increase in the smoking-attributable deaths from lung cancer in both sexes.

Adolescent↗
PubMedDate not supplied

Obesity, sodium intake, and blood pressure in adolescents.

It has been postulated that increased dietary sodium associated with greater food intake by obese people is a mechanism for the relationship between obesity and blood pressure (BP). We have evaluated this hypothesis by exploring the interrelationships of measures of obesity, sodium intake, and BP in 248 "normal" adolescents, 16 to 17 years of age. As an index of sodium intake, the sodium excretion in three overnight urine collections was used. As a more specific index of saltiness of diet, we used a ratio of sodium excretion to calorie intake, with calories estimated from 3-day diet records and dietary interview. Body weight and other measures of obesity showed a positive relationship with systolic blood pressure (SBP), but not with diastolic (K5) blood pressure (DBP5). Measures of overnight sodium excretion were positively correlated with body weight and calculated body fat percentage, suggesting that heavier people indeed ingest more sodium. This may result not from increased intake of food per se, but from increased saltiness of diet, since calorie intake did not increase with body weight. No significant relationships were found between BP and concurrent measures of sodium excretion or diet saltiness.

Adolescent↗