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Biomedical subjects

G Ryan

Publications and source records attributed to G Ryan.

160 records · Page 9Linked to original sources
PubMed1981

Ineffectiveness of intravenous ascorbic acid as an acidifying agent in man.

The acidifying effect of intravenous (IV) ascorbic acid was studied in seven healthy adult volunteers. After obtaining baseline urine and blood samples, 2-g IV doses of ascorbic acid were administered to each subject during a 20-minute period. Venous blood samples were obtained at times 0.5, 1, and 2 hours, and urine was collected at times 0.5, 1, 2, and 3 hours. Our results show that venous blood pH, plasma bicarbonate concentration, urine PCO2, and urine bicarbonate excretion did not change significantly during the study period. Urinary titratable acidity, ammonium excretion, and net hydrogen ion excretion decreased, and urinary pH actually showed a significant rise at two hours. We therefore conclude that IV ascorbic acid administered in recommended doses does not effectively acidify urine.

Acid-Base Equilibrium↗
PubMed1980

Renal impairment and its reversibility following variable periods of complete ureteric obstruction.

There is debate concerning the time course and degree of recovery possible after relief of complete unilateral ureteric obstruction. This study in dogs investigates these features. One ureter was occluded for varying periods, and then reimplanted into the bladder. Recovery was monitored by Tc-Sn-labelled diethylene triamine penta acetic acid (D.T.P.A.) scans and renograms together with creatinine clearance studies. The morphological changes were also studied. There was found to be a progressive loss of functional recovery with increasing periods of obstruction, though this was dramatically improved by contralateral nephrectomy once recovery had stabilized. Increased radial scarring developed in the kidney following increasing periods of obstruction.

Animals↗
PubMed1980

Preservation of urinary postprandial alkaline tide despite inhibition of gastric acid secretion.

Ingestion of food leads to a rise in urinary pH. This phenomenon is commonly known as "postprandial alkaline tide" and is generally attributed to acid secretion in the stomach. To examine this hypothesis, we studied the changes of urinary pH, H+ concentration, PCO2, and bicarbonate in nine healthy volunteers with and without histamine H2 receptor blockade, using cimetidine and placebo medication. Postprandial alkaline tide persisted and was even exaggerated during treatment with cimetidine. Preservation of postprandial urinary alkaline tide, despite the expected inhibition of gastric acid secretion by cimetidine, tends to exclude a causal relation between alkaline tide and gastric acid secretion.

Acid-Base Equilibrium↗
PubMed1967

Cyclopropenone.

Explore the source record for details and available documents.

Alkenes↗
PubMedDate not supplied

Adverse reactions to beta 2-agonist bronchodilators.

Beta 2-Agonists are safe and effective bronchodilator drugs. Their major adverse effects of skeletal muscle tremor, tachycardia and various metabolic effects are mediated by beta-adrenoceptor stimulation and are reversible. Skeletal muscle tremor is the most frequent dose-limiting side effect. It may be reduced by commencing treatment with a low dose and if it persists another beta 2-agonist may be tried. Other side effects such as cardiac arrhythmias and reduction in PaO2 are a serious potential problem in some susceptible asthmatics. However, they are infrequent or of a mild degree and are generally outweighed by the good control of asthma produced by beta 2-agonists. Side effects from beta 2-agonist therapy can be minimised by use of the inhaled route which selectively delivers the drug to the airways. Furthermore, selective tolerance develops to their side effects. The dose of a beta 2-agonist should be assessed on the basis of therapeutic effect and the level of tolerance to its side effects. Recommended doses of beta 2-agonists used for long term therapy do not cause clinically significant desensitisation of airway beta-adrenoceptors, although this may become a relevant problem in patients who are regularly receiving very high doses. Intravenous beta 2-agonists have a place in the treatment of severe asthma not responding to nebuliser therapy. In this life-threatening situation with severe airflow obstruction, monitoring of heart rate, PaO2, plasma potassium and the electrocardiogram should be mandatory and supplemental oxygen given so that serious adverse effects are presented.

Adrenergic beta-Agonists↗
PubMedDate not supplied

Clinical workload decreases the level of aerobic fitness in housestaff physicians.

PURPOSE: To examine the relationship between clinical workload and aerobic fitness. METHODS: Twenty healthy intern and resident volunteers were studied in a cross over manner to compare their aerobic fitness after a 1 month "easy" clinical rotation (ECR) to that after a 1 month "hard" clinical rotation (HCR). The ECR and HCR were prospectively estimated as requiring <60 (ECR) and >70 (HCR) total hours per week of hospital work respectively. Aerobic fitness was determined by directly measuring peak oxygen uptake (peakVO2) during peak cycle exercise testing after each rotation. Clinical workload for the month preceding the exercise test was estimated by documenting the amount of hospital work and sleep lost because of on-call duties. The average weekly amount of effective aerobic training for each rotation was also documented. RESULTS: Trainees had a 206.4 (P = 0.0019, 95% CI 94-318.8) mL/min or 3 mL/kg/min (P = 0.0019, 95% CI 1.5-4.4) improvement of peakVO2 after the ECR compared with the HCR. Trainees averaged 1 (95% CI 0.16-1.81) less hour per week of exercise training, 34.1 more hours per week of hospital work (95% CI 23.0-45.3, P < 0.0001) and lost 19.1 hours more sleep per month (95% CI 11.8-26.4, p < 0.0001) during the HCR compared with the ECR. There was no correlation between changes in peakVO2 and changes in exercise training between the two rotations. CONCLUSION: Clinical workload seems to adversely affect aerobic fitness independent of changes in exercise training. This supports previous less-objective survey data.

Adult↗
PubMedDate not supplied

Mid-trimester thoracoamniotic shunting for the treatment of fetal primary pleural effusions in a twin pregnancy. a case report.

Thoracoamniotic shunting has been described as having a beneficial role in the antenatal management of primary pleural effusions in singleton pregnancies. We report a case of a twin pregnancy in which progressive pleural effusions and hydrops were diagnosed in one of the fetuses at 16 weeks of gestation. An initial evaluation ruled out underlying genetic and anatomic abnormalities in both twins. At 19 weeks gestation, the first procedure of bilateral thoracoamniotic shunting was performed in the affected fetus, subsequent to which the lungs re-expanded and the hydrops resolved. Three additional shunt replacements and one therapeutic amniocentesis were required on follow-up. At 35 weeks, labor was induced. The first fetus (healthy) was delivered vaginally and the second fetus (affected) was delivered by cesarean section. Both neonates are healthy at one year follow-up.

Adult↗
PubMedDate not supplied

Midtrimester thoracoamniotic shunting for the treatment of fetal hydrops.

The management of fetal hydrops in the second trimester is changing as the underlying etiologies are better understood. We report a case which was diagnosed at 18 weeks gestation. There was no underlying anatomical abnormality. Fetal blood sampling confirmed a normal karyotype and there was no evidence of fetal infection. Bilateral thoracocentesis and paracentesis caused temporary improvement of the fetal condition but subsequent fluid reaccumulation was noted within the left pleural cavity. A pleuroamniotic shunt inserted at 22 weeks caused permanent resolution of the hydrops. The infant was normal at 1-year follow-up.

Adult↗
PubMedDate not supplied

Fetal urine production rates following intrauterine transfusion.

This study investigates the hypothesis that following an intrauterine, intravascular transfusion (IVT), one of the physiologic adaptations might be an increase in the fetal urine production. The hourly fetal urine production rate (HFUPR) was measured for the first hour following 12 transfusions and for 24 h following 5 transfusions in anemic isoimmunized fetuses. The HFUPR was also measured in 5 control fetuses who underwent fetal blood sampling without transfusion. Fetal hemoglobin, hematocrit and blood viscosity were measured before and after each transfusion. The HFUPR fell significantly from a mean (SEM) of 19.2 (2.85) to 7.4 (2.2) ml/h, and remained low for at least 4 h posttransfusion returning to pretransfusion rates by 24 h. There was no change in the HFUPR in the control fetuses. The study suggests that in human fetuses the rapid excretion of excess fluid via the renal tract is not an acute adaptive response to an IVT.

Adaptation, Physiological↗
PubMedDate not supplied

Comparison of "Duphalac" and "irritant" laxatives during and after treatment of chronic constipation: a preliminary study.

A multi-centre trial was carried out to compare the effectiveness in the treatment of chronic constipation of a lactulose preparation ("Duphalac") and "irritant" laxatives containing senna, anthraquinone derivatives or bisacodyl. The results, in 164 patients, indicate that the lactulose prepartion was more effective than the "irritant" laxatives. By Day 7, 58% of the lactulose-treated group were passing a normal stool whereas only 42% of the patients receiving an "irritant" laxative did so at the same stage in treatment. The lactulose preparation was shown to have a persistent CARRY-OVER" EFFECT, AND THIS EFFECT WAS SEEN IN SIGNIFICANTLY MORE PATIENTS RECEIVING "Duphalac" than in the "irritant" laxative group.

Adolescent↗
PubMedDate not supplied

It's not football.

Today I am as happy as I could ever be. I have created a lot out of very little, I have worked full time, played full time, got full-time friends, full-time independence, had full-time love and am lucky enough to be with my new full-time love who helps me a great deal both physically and mentally. It is definitely no fun coughing until your chest is sore in the morning, afternoon and evening. Having wringing night-sweats from cepacia. Wanting to sleep more than Mr Sleep from Sleepland. Taking tablets the size of which sunk the Belgrano. Finding time for physiotherapy, eating the right meals, playing on my Playstation. Depression has got through on previous occasions, but not for long, and it has never resulted in anything more than a 'wake up and smell the coffee' call from myself. Having CF is no ball game (otherwise it would be called football or something!), but I have had a lot of fun and will continue to do so for however long. Two years, five years, 20 years--who's to say, not me. We could all have the same left, I just hope that everyone has as much fun.

Activities of Daily Living↗