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Biomedical subjects

P Bell

Publications and source records attributed to P Bell.

At least 73 records · Page 4Linked to original sources
PubMed1991

A preliminary study of the effects of flosequinan on psychomotor function in healthy volunteers.

The central nervous system effects of flosequinan (100 mg), a chemically novel quinolone vasodilator, were assessed by a double-blind crossover comparison with placebo and diazepam (10 mg) in 12 healthy volunteers. After five practice sessions on a battery of automated psychomotor tests, assessments of psychomotor function and mood ratings were made on each volunteer at baseline and 1, 3, 6 and 24 h after dosing. Compared with placebo, diazepam (10 mg), the verum control, significantly (p less than 0.05) reduced subjective alertness, impaired critical flicker fusion threshold at 1 and 3 h, digit symbol substitution at 6 h, overall total choice reaction time and overall rate on two of five finger tapping tests. Flosequinan (100 mg), however, was indistinguishable from placebo in all tests with two contrasting exceptions: improved alternate right and left finger tapping (mean 5.1/s) compared to either diazepam (4.7/s) or placebo (4.8/s) (p less than 0.05), and impaired digit symbol substitution at 6 h (45.7/min) in comparison with placebo (50.7/min) (p less than 0.01). Ten volunteers reported 12 adverse effects after flosequinan treatment (10 of which were headaches), two reported drowsiness after diazepam and one reported headache after placebo. It was concluded that flosequinan has no central nervous system depressant effects despite the occurrence of headache in 10 volunteers.

Administration, Oral↗
PubMed1991

AIDS: knowledge and attitudes of student nurses in Australia and Canada.

In summary it would appear that Australian and Canadian nursing students, at least in these limited samples, generally have similar knowledge and attitudes regarding AIDS. This study, with its acknowledged limitations, could be regarded as a pilot study for future collaborative comparative research, targeting a wider population of nursing students in two very similar countries.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Intraoperative management of patients with heparin-induced thrombocytopenia.

For 11 patients with confirmed heparin-induced thrombocytopenia, we used reversible platelet inhibition with iloprost, a stable prostacyclin analogue, to permit safe heparin administration for cardiac (n = 9) or vascular (n = 2) operations. In vitro, iloprost (0.01 mumol/L) prevented both heparin-induced platelet aggregation and 14C-serotonin release in all patients. Therefore, intraoperatively, a continuous infusion of iloprost was started before administration of heparin and was continued until 15 minutes after administration of protamine. For cardiac patients, after heparin administration, the whole blood platelet count did not change (171,000 +/- 29,000/microL versus 174,000 +/- 29,000/microL, mean +/- standard error of the mean); no spontaneous platelet aggregation was observed, and plasma levels of the alpha-granule constituents platelet factor 4 and beta-thromboglobulin increased from 38 +/- 14 and 140 +/- 18 ng/mL to 591 +/- 135 and 235 +/- 48 ng/mL, respectively. Fibrinopeptide A levels actually decreased from 287 +/- 150 to 27 +/- 6 ng/mL. Furthermore, adenosine diphosphate-induced platelet activation was preserved, postoperative bleeding times were unchanged, and no heparin-related deaths occurred. Similar results were obtained in both vascular patients. We conclude that temporary platelet inhibition with iloprost now permits safe heparin administration in all patients with heparin-induced thrombocytopenia who require a cardiac or vascular operation.

Adult↗
PubMed1990

Psychological consequences of the Enniskillen bombing.

Eleven people were killed and 60 injured in the Enniskillen bombing of November 1987. Survivors were psychologically appraised six months and one year later. At six months 50% had developed post-traumatic stress disorder (PTSD). This group comprised more females than males. However, all victims had high scores on the GHQ. We found no correlation between psychological injury (as measured by the GHQ) and physical injury (as measured by the ISS), calling into question previous assertions.

Adolescent↗
PubMed1990

Choice and use of tracers.

The isotope dilution method has been widely employed to measure glucose turnover in man. The validity of this technique depends upon several assumptions. First, it is assumed that the selected model of glucose kinetics is valid. Under nonsteady state conditions this has recently been challenged for the most commonly used single compartment model. Secondly, it is assumed that the isotope is metabolized in the same manner as unlabeled glucose. If the isotope loses its label when subject to a substrate cycle (for example, [2-3H]glucose in glucose to glucose 6-phosphate cycling), an overestimate of glucose disposal will result. In contrast, if isotope that has been cleared (for example [6-3H]glucose in hepatic glucogen) is recycled into the systemic circulation, an underestimation of glucose turnover will result. Thirdly, it is assumed that measurement of specific activity is accurate. It has recently been shown that many commercially available tritiated (but not 14C) isotopes contain radioactive nonglucose contaminants which have a slower clearance rate than glucose under conditions of high glucose turnover. This can result in overestimates of specific activity and underestimates of glucose appearance, leading to calculated negative hepatic glucose release. While this problem may be avoided with purified tritiated glucose tracers, a similar problem with stable isotopes of glucose remains to be determined. In summary, the choice of glucose isotope should reflect the probability of substrate cycling and isotope cycling in the experiment in question. Care should be taken to ensure purified isotopes are selected and that the model of glucose kinetics used is valid during the conditions to be studied.

Animals↗
PubMed1990

Hostel placement of mentally handicapped patients in Northern Ireland.

All patients discharged to hostels from an 800 bed hospital for the mentally handicapped were studied over a 12 year period. Those whose placement was successful were compared with those who returned to the hospital. Youth and early institutional upbringing were associated with failure of placement. Twelve specific problems were identified by hostel staff and of these aggression, psychosis, absconding and interpersonal difficulties were associated with failure. A worrying trend was that the more modern hostels had a lower success rate and a higher proportion of problems than those which were older and more established.

Adult↗
PubMed1989

Femoro-popliteal versus femoro-distal bypass grafting for limb salvage in patients with an "isolated" popliteal segment.

In a prospective, multicentre trial, 59 patients with an ischaemic limb and an "isolated" popliteal segment on angiography were randomised to undergo infrainguinal bypass grafting to either the popliteal segment or to a reconstituted distal vessel lower in the calf. Limb salvage was attained with 88% of the femoro-popliteal grafts and 80% of the femoro-distal grafts. There was no difference in the one year graft patency rate between the femoro-popliteal group (79%) and the femoro-distal group (70%). Mean postoperative increase in ankle/brachial pressure index was similar in the two groups despite the presence of occluded or significantly diseased vessels distal to the popliteal anastomoses. Technical difficulties were encountered in 8% of the popliteal group and 24% of the distal group. Femoro-distal bypass grafting confers no apparent benefit over femoral bypass grafting into a patent popliteal segment, even though the popliteal run-off is impaired or occluded.

Aged↗
PubMed1989

Electrophysiologic effects of Org 7797, a new steroidal antiarrhythmic agent: comparison with class 1a, 1b, and 1c drugs.

The in vitro electrophysiologic effects of a new class I steroidal antiarrhythmic agent, Org 7797 (2-10 microM) were evaluated in porcine ventricular and Purkinje tissue using conventional microelectrode techniques. Org 7797-induced decreases in Vmax were both frequency- and voltage-dependent. Both the rate of onset and the time course of decay of sodium channel block were slow and similar to those obtained with the 1c drug propafenone. The kinetics of block by lignocaine (1b) were fast whereas those of disopyramide (1a) were intermediate. Rate constants (determined at 1.0 Hz) were 0.187, 0.078, and 0.074 for disopyramide, propafenone, and Org 7797, respectively, in concentrations giving approximately equivalent decreases in Vmax. Onset block with lignocaine was too fast to measure. The effective refractory period (ERP) was prolonged to a greater extent by lignocaine and disopyramide than by propafenone or Org 7797, but the increase in ERP in response to disopyramide resulted largely from prolongation of action potential duration (APD). The effects of Org 7797 on ERP relative to APD were more similar to those of propafenone. We conclude that Org 7797 is a class 1c agent.

Action Potentials↗
PubMed1989

Psychomotor performance and counterregulatory responses during mild hypoglycemia in healthy volunteers.

The effect of mild hypoglycemia on psychomotor performance and counterregulatory responses was studied among 12 healthy volunteers. Each volunteer received two modified hyperinsulinemic glucose clamps. One morning, plasma glucose was held constant at euglycemic levels (4.9 mM) for 95 min, and another morning, it was lowered over 35 min and then held constant at hypoglycemic levels (3.4 mM) for 60 min. A battery of psychomotor tests and a questionnaire assessing hypoglycemic symptoms were administered before and repeated during the last 30 min of each clamp. The questionnaire and three selected psychomotor tests were also administered repetitively during the 1st h of each clamp. During the hypoglycemic studies, a rise was seen in plasma epinephrine and pancreatic polypeptide at 45 min. An increase in symptom scores was first recorded at 50 min during the hypoglycemic studies [median 4 (range 0-13) vs. 2 (5-6), P less than .05]. Performance was impaired on two psychomotor tests included in the battery. One was the trail making test on fine motor performance (-19.3 +/- 4.2 targets/min, mean +/- SE vs. 1.2 +/- 4.8 targets/min, P less than .05), and the other was the digit-symbol substitution (DSS) test on information processing and memory (18 +/- 3 vs. 29 +/- 4 symbols/min, P less than .03). Of the tests administered during the 1st h, performance was impaired on the DSS. This impairment became significant at 45 min (14 +/- 4 vs. 22 +/- 4 symbols/min, P less than .005). In conclusion, mild hypoglycemia selectively impairs psychomotor performance in healthy volunteers but not before the onset of glucose counterregulation and warning symptoms.

Adult↗
PubMed1988

Post-traumatic stress in Northern Ireland.

The sample studied was a group of 643 adults each seeking compensation for "Nervous Shock" and seen by a single Belfast psychiatrist for medico-legal assessment. Demographic information, risk factors, diagnosis, type of incident, symptoms and outcome were recorded for each patient. From the symptoms recorded, a subgroup of 23% were identified as suffering from Post-Traumatic Stress Disorder (PTSD) as defined in DSM III. This subgroup tended to be older, included more females, had more depressive symptoms and had more severe, prolonged disturbance. The findings document our experience of PTSD in the special context of Northern Ireland and suggest it may be a more useful term in describing psychological reaction to violence than the nebulous concept of "Nervous Shock" used at present by our courts.

Adult↗
PubMed1988

Post-traumatic stress disorder and civil violence in Northern Ireland.

The case records of 499 victims of civil and terrorist violence were examined, and the presence or absence of post-traumatic stress disorder (PTSD) and associated features recorded. The results support the face, and predictive, validities of PTSD. 'Acting as if the event were reoccurring' and 'survivor guilt' seemed not to be characteristic symptoms, and the homogeneity of the emotional state in PTSD was questionable. Only marital disharmony and suicidal behaviour were associated complications. PTSD seemed to be found in a wide range of stressors, but the danger in over-reliance on results from combat veterans is emphasised.

Adult↗
PubMed1987

Insulin action in non-insulin-dependent diabetes mellitus: the relationship between hepatic and extrahepatic insulin resistance and obesity.

To determine the contribution of obesity to the insulin resistance of non-insulin-dependent diabetes mellitus, insulin dose response curves for suppression of glucose production and stimulation of glucose utilization were generated in lean and obese diabetic patients and compared to those observed in weight-matched nondiabetic subjects. Glucose utilization during 0.4, 1.0, and 10.0 mU/kg x min insulin infusions (producing insulin concentrations ranging from approximately 50 to 2,000 microU/mL) was lower (p less than .02 to .001) in lean and obese diabetic patients compared to weight-matched nondiabetic subjects indicating insulin resistance. Glucose utilization was not correlated with obesity in the diabetic subjects. Suppression of glucose production was impaired (P less than .03 and .001) in both the lean and obese diabetic subjects at physiologic but not supraphysiologic insulin concentrations. We conclude that patients with NIDDM have both hepatic and extrahepatic insulin resistance, the severity of which appears to be independent of the degree of obesity.

Blood Glucose↗
PubMed1987

Autosomal dominant polycystic kidney disease in childhood: a longitudinal study.

One hundred fifty-four children aged eighteen years or younger from 83 families with autosomal-dominant polycystic kidney disease were studied by ultrasonography or excretory urography. Twenty-three children had bilateral renal involvement with at least five cysts (ADPKD), 28 children were classified as suspicious (SADPKD), and 103 children had no renal involvement (NADPKD) detected by ultrasound. Seventy-four percent of the ADPKD children had signs or symptoms compatible with the diagnosis of ADPKD, compared to 34% of the NADPKD and 36% of the SADPKD children (both P less than 0.05). Three of the 23 ADPKD children had elevated serum creatinines at the time of diagnosis, while all of the NADPKD and SADPKD children had normal renal function. Renal area by ultrasonography (width X depth) was greater among the ADPKD children compared to the SADPKD and NADPKD groups (P less than 0.05). On follow-up 30 of the 37 NADPKD children remained NADPKD, three were reclassified as SADPKD, and four progressed to ADPKD after 18 years of age. All of the NADPKD children had normal renal function on follow-up. Overall, 14 children had suspicious ultrasounds at some point with follow-up ultrasonography and ten (71%) progressed to ADPKD. All SADPKD children maintained normal renal function. Eight of 18 ADPKD children had progression of the disease manifested by development of hypertension and/or decreased renal function. Three children progressed to end-stage renal disease. Five ADPKD children were diagnosed before one year of age, two of them via prenatal ultrasonography. One fetus was aborted after documentation of oligohydramnios.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1987

Effects of tolazamide and exogenous insulin on pattern of postprandial carbohydrate metabolism in patients with non-insulin-dependent diabetes mellitus. Results of randomized crossover trial.

To determine whether therapy with exogenous insulin or sulfonylureas results in a postprandial pattern of carbohydrate metabolism in patients with non-insulin-dependent diabetes mellitus (NIDDM) that resembles that in nondiabetic individuals, we employed a dual-isotope technique combined with forearm catheterization to examine meal disposition in NIDDM patients, before and after 3 mo of therapy with tolazamide and after 3 mo of therapy with exogenous insulin, with a randomized crossover design. Results were compared with those observed in nondiabetic subjects. Although both forms of therapy improved chronic glycemic control (glycosylated hemoglobin concentration went from 9.6 +/- 0.7 to 7.6 +/- 0.5 and 7.1 +/- 0.2%, respectively, P less than .01), exogenous insulin resulted in a lower postprandial glycemic response than tolazamide (P less than .001). Both agents comparably increased (P less than .01) fasting and integrated postprandial insulin concentrations. However, the initial rate of postprandial increase was greater with exogenous insulin (P less than .05). Tolazamide (P less than .05) but not exogenous insulin increased postprandial C-peptide concentrations. However, tolazamide did not improve the deficient early insulin release. Both agents (P less than .05) lowered postabsorptive hepatic glucose release (from 2.8 +/- 0.3 to 2.3 +/- 0.2 mg . kg-1 . min-1), but not to normal rates (1.8 +/- 0.1 mg . kg-1 . min-1).(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Glucose↗