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Biomedical subjects

J Potts

Publications and source records attributed to J Potts.

36 records · Page 2Linked to original sources
PubMed1990

Plasma beta-endorphin concentration: response to intensity and duration of exercise.

Twelve college-age men exercised on a bicycle ergometer to VO2max and at 60, 70, and 80% VO2max for 30 min to determine the effects of exercise intensity on plasma beta-endorphin (B-EP). The time course for alterations in B-EP and the relationship to lactate were also examined. Following the VO2max test, the three submaximal intensities were completed on separate days using a counter-balanced design. Blood was sampled from an indwelling venous catheter at rest during exercise and recovery to assess the time course response. B-EP content was determined by radioimmunoassay (Immunonuclear) with less than 5% cross-reactivity to B-LPH. At rest, B-EP content was similar across visits, 4.34 +/- 0.36 pmol.l-1. The 60% intensity did not elevate B-EP at any time measured. B-EP content increased by 15 min at 70% VO2max with a further increase at 30 min. B-EP remained elevated during the 20 min recovery. At 80% VO2max B-EP content increased by 5 min. B-EP continued to increase during the exercise and peaked at 21.91 +/- 2.03 pmol.l-1 5 min into the recovery. Lactate showed a mild correlation with B-EP (r = 0.43) at 80% VO2max. A significant correlation (r = 0.78) between lactate and B-EP did occur with the VO2max test. It is concluded that an exercise intensity of at least 70% VO2max for 15 min is needed to increase plasma B-EP. Furthermore, the higher the exercise intensity the more rapid the onset for increases in plasma B-EP.

Adult↗
PubMed1989

Gastrointestinal tuberculosis: resurgence of an old pathogen.

Thirteen patients with gastrointestinal tuberculosis (GITB) were treated at our hospitals from 1977-1987. Ten of these patients were seen during the last four years. Three patients required operative intervention for management of complications of their disease. This review discusses the presentation, diagnosis, and operative management of GITB. The authors feel that the increasing prevalence of GITB noted in their institution is primarily the result of the growing prevalence of mycobacterium tuberculosis pneumonia across the nation. With the recent influx of patients from areas of endemic tuberculosis and the increasing number of immunosuppressed patients, a surge in the number of patients presenting with GITB is likely to occur in the United States. Surgeons must be conversant with the diverse clinical features and operative management of this disease.

Cecal Diseases↗
PubMed1989

Effects of nearpoint visual stress on psycholinguistic processing in reading.

To date, there have been few studies to evaluate directly the relationship between binocular visual stress and reading performance. This study employed the cloze procedure to demonstrate the effects of nearpoint stress on performance and efficiency in reading comprehension. Using 19 third year optometry students as subjects, binocular stress was simulated by -2.00 D lenses. Performance, as determined by the time to complete the task, was significantly reduced (p less than .03), but no significant differences in accuracy scores were measured.

Adult↗
PubMed1988

Widespread occurrence of calicin, a basic cytoskeletal protein of sperm cells, in diverse mammalian species.

A novel cytoskeletal element consisting of dense webs of thin (3-14 nm) filaments surrounding the nucleus of the sperm head has recently been isolated and shown to be associated with certain major basic proteins. Using antibodies specific for calicin, a prominent Mr-60,000 cytoskeletal protein of the posterior calyx of bull sperm heads detected in immunoblotting on gel electrophoretically separated polypeptides as well as in immunofluorescence and immunoelectron microscopy, we show that the same--or an immunologically related--polypeptide occurs in sperm heads of other species with greatly different morphology, including human, boar, guinea pig, hamster, rat and mouse. The calicin localization in the various species is described and discussed in relation to the specific sperm morphology.

Animals↗
PubMed1984

Portal vein perfusion of the isolated rat liver: some markers of hyperthermic liver damage.

The cytotoxic effects of hyperthermia on tumours are readily measured. Parameters of injury to normal tissues are needed to evaluate therapeutic potential. Fifty-five isolated rat livers were perfused in vitro for 180 min in order to determine parameters of hyperthermic injury. During this period they were heated for 1 h at temperatures ranging from 37 degrees to 45 degrees and then assessed for evidence of hyperthermic injury. The most critical indicator of hyperthermic injury was sustained depression of bile production. Bile secretion decreased by 80% after heating at temperatures above 42 degrees. Aspartate amino transferase (AST) release increased significantly at temperatures of 42 degrees and above. Potassium and variable amounts of glucose were released into the medium during heating, reflecting temporary changes in metabolism at high temperatures.

Animals↗
PubMed1978

Elevated ejection fractions in patients with the anginal syndrome and normal coronary arteriograms.

The etiology of chest pain in patients with the anginal syndrome and normal coronary arteriograms has not been established. There has been no explanation for the association of electrocardiographic, hemodynamic, and myocardial metabolic abnormalities consistent with myocardial ischemia observed in some patients with this disorder. Historical, clinical, laboratory, and hemodynamic data of 45 patients (24 females, 21 males), mean age 47.5 years, with chest pain and normal coronary arteriograms are reviewed. Left ventriculograms were analyzed utilizing the single-plane cineangiographic measurement of left ventricular volume. Systolic ejection fractions for the 45 patients ranged from 0.66 to 0.91 (mean 0.80 +/- 0.01 SEM). Ventricular volumes determined angiographically revealed mean end-diastolic and end-systolic volumes of 83 +/- 5 ml and 18 +/- 2 ml, respectively. The mean changes in longitudinal and transverse segmental axis shortening that occurred during ventricular systole were 28.8% and 50.7%, respectively. These elevated values for ejection fraction, and reduced measurements of ventricular volumes, indicate that some patients with chest pain and normal coronary arteriograms may have small hearts with hyperdynamic ventricular contraction. These findings suggest that hyperdynamic ventricular contraction may play a causative role in the development of transient, angina-like chest pain in these patients. The etiology of the proposed hyperdynamic ventricle is unknown, but it may be attributable to increased beta-sympathetic stimulation of the myocardium.

Adult↗
PubMed1977

Phonocardiographic and echocardiographic features of Lillehei-Kaster mitral prosthesis.

Fifteen patients were studied with phonocardiography (phono) and echocardiography (echo) three to 13 months after mitral valve replacement with Lillehei-Kaster mitral valve prostheses. Echo measurements in all patients included prosthesis excursion (DE), opening velocity (OV), closing velocity (CV), and Q-to-mitral prosthesis closure (Q-MPC). In five patients, further, echo measurements included isometric contraction period (ICP), left ventricular ejection time (LVET), and time to completion of aortic valve opening (TCAO). Phono measurements in all patients included pre-ejection period (PEP), LVET, and PEP/LVET. Further phono measurements in the same five patients in whom further echo measurements were performed included Q to first heart sound (Q-S1), ICP, and isometric relaxation period (IRP). Phono and echo measurements were done sequentially. The echo results showed widespread values for DE, OV and CV with no correlation between clinical state, size of prosthesis, or postoperation duration. There was a positive correlation between CV and OV, r + 0.65. Q-MPC by echo averaged 72 msec, which is longer than reported values for Q-to-mitral valve closure in normal people. Similarly, ICP by echo was shorter than ICP by phono in every patient. Of the phono measurements IRP was shortest (45 msec) in one patient in congestive heart failure with a possible prosthesis malfunction. We conclude that echo- and phonocardiography are useful tools in evaluating mitral prosthesis function, but because normal values are widespread, individual measurements may be useful for followup in the same individual. Precise measurement of subdivisions of systolic intervals are now possible with these techniques.

Adult↗
PubMed1975

Fluid therapy in severe systemic reaction to radiopaque dye.

Two patients developed severe vascular collapse after left ventriculography with organic iodides. Hemodynamic monitoring showed marked reduction in systemic pressures. In one patient there was no response to the standard therapeutic measures in anaphylactic reactions, and prompt response to fluid administration was obtained. In the second patient response was prompt to fluids, adrenalin, and hydrocortisone.

Anaphylaxis↗
PubMedDate not supplied

Renal nurse on call.

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Hospital Units↗