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Biomedical subjects

J Watson

Publications and source records attributed to J Watson.

At least 73 records · Page 4Linked to original sources
PubMed2000

A comparison of depression and styles of coping in male and female GA members and controls.

Depression and maladaptive coping styles are important components of theories of pathological gambling and are frequently foci of treatment with individuals with gambling problems. The present study aimed to improve understanding and treatment of pathological gambling by comparing levels of depression and styles of coping in male and female members of Gamblers Anonymous (GA) to a group of non-pathological gambling controls matched according to gender, age, education, and income. Pathological gambling was measured by the South Oaks Gambling Scale, depression by the Beck Depression Inventory, and coping styles by the Problem-Focused Styles of Coping inventory. Results showed that GA members reported significantly higher levels of depression and more maladaptive styles of coping than controls. Pathological gamblers' greater use of maladaptive coping was evident even when variance attributable to depression was removed, suggesting that their coping deficits may be pervasive. Female subjects reported significantly greater levels of depression and maladaptive coping than their male counterparts. Implications for treating depression and coping styles in pathological gamblers are discussed.

Journal Article↗
PubMed2000

5-HT(1A) receptor agonist-antagonist binding affinity difference as a measure of intrinsic activity in recombinant and native tissue systems.

1. It has been reported that radiolabelled agonist : antagonist binding affinity ratios can predict functional efficacy at several different receptors. This study investigates whether this prediction is true for recombinant and native tissue 5-HT(1A) receptors. 2. Saturation studies using [(3)H]-8-OH-DPAT and [(3)H]-MPPF revealed a single, high affinity site (K(D)approximately 1 nM) in HEK293 cells expressing human 5-HT(1A) receptors and rat cortex. In recombinant cells, [(3)H]-MPPF labelled 3 - 4 fold more sites than [(3)H]-8-OH-DPAT suggesting the presence of more than one affinity state of the receptor. [(3)H]-Spiperone labelled a single, lower affinity site in HEK293 cells expressing h5-HT(1A) receptors but did not bind to native tissue 5-HT(1A) receptors. These data suggest that, in transfected HEK293 cells, human 5-HT(1A) receptors exist in different affinity states but in native rat cortical tissue the majority of receptors appear to exist in the high agonist affinity state. 3. Receptor agonists inhibited [(3)H]-MPPF binding from recombinant 5-HT(1A) receptors in a biphasic manner, whereas antagonists and partial agonists gave monophasic inhibition curves. All compounds displaced [(3)H]-8-OH-DPAT and [(3)H]-spiperone binding in a monophasic manner. In rat cortex, all compounds displaced [(3)H]-MPPF and [(3)H]-8-OH-DPAT in a monophasic manner. 4. Functional evaluation of compounds, using [(35)S]-GTPgammaS binding, produced a range of intrinsic activities from full agonism, displayed by 5-HT and 5-CT to inverse agonism displayed by spiperone. 5. [(3)H]-8-OH-DPAT : [(3)H]-MPPF pK(i) difference correlated well with functional intrinsic activity (r=0.86) as did [(3)H]-8-OH-DPAT : [(3)H]-spiperone pK(i) difference with functional intrinsic activity (r=0.96). 6. Thus agonist : antagonist binding affinity differences may be used to predict functional efficacy at human 5-HT(1A) receptors expressed in HEK293 cells where both high and low agonist affinity states are present but not at native rat cortical 5-HT(1A) receptors in which only the high agonist affinity state was detectable.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed2000

A biodialysis system for liver support tested in a porcine hepatic failure model.

BACKGROUND: A practical liver support system for patients in fulminant hepatic failure (FHF) remains a needed therapeutic modality. A new method of bioartificial liver support, the liver biodialysis system (LBDS), is described. METHODS: Porcine hepatocytes, removed from direct contact with the treated subject's circulation, are in culture in a bioreactor which is combined in a dialysis circuit for patient treatment. The LBDS was tested in a porcine ischaemic hepatic failure model. RESULTS: The viable hepatocyte content of the bioreactor was 2.49 +/- 0.72 x 10(10). Cells remained viable in culture throughout the experiments (30 +/- 3 h) without evidence of immunological damage. A decrease in the degree of accumulation in the blood of ammonia (P < 0.02) and of 14 amino acids (P < 0.001) was achieved by the LBDS. Cerebral perfusion pressure was maintained at significantly higher levels in LBDS-treated animals (P < 0.05). CONCLUSIONS: In the LBDS, hepatocytes in large numbers and satisfactory culture conditions in a bioreactor have sustained viability and function. When combined in a dialysis circuit for the treatment of FHF pigs, immune reactions between the blood and hepatocytes were prevented and beneficial metabolic effects were observed.

Amino Acids↗
PubMed2000

Driving and insulin--consensus, conflict or confusion?

AIMS: All drivers requiring insulin treatment must be able to demonstrate satisfactory diabetic control and recognition of hypoglycaemic symptoms before being allowed to drive a motor vehicle. Clinicians have a duty to discuss fitness to drive with their patients. However, is the advice given consistent and in line with the regulations published by the Driver and Vehicle Licensing Authority (DVLA)? METHODS: Six 'real-life' case scenarios were posted to clinicians (consultant diabetologists, specialist registrars and diabetes specialist nurses) within Wessex, UK. The identical cases were also sent to the DVLA for their comments. RESULTS: Sixty-six doctors (36 consultants) and 70 diabetes specialist nurses were contacted by postal questionnaire of which replies were received from 17 consultants (47%), 17 specialist registrars (57%) and 39 diabetes specialist nurses (56%). Although there was general agreement in cases of hypoglycaemia unawareness, there was disagreement where patients had or were at risk of unstable control albeit for a short time. CONCLUSIONS: Patients treated with insulin may receive conflicting information concerning their ability to drive.

Adolescent↗
PubMed2000

Fatigue during acute isovolemic anemiain healthy, resting humans.

BACKGROUND: Transfusion guidelines recommend that clinicians assess patients for signs and symptoms of anemia before the transfusion of RBCs. However, studies of signs and symptoms associated with acute isovolemic anemia are limited. The objective of this study was to determine whether acute reduction of Hb concentration to 5 g per dL would result in fatigue, tachycardia, or hypotension in resting, young, healthy, isovolemic humans, and whether changes were reversible with RBC transfusion. STUDY DESIGN AND METHODS: Conscious, resting, healthy adults less than 35 years old (n = 8) underwent acute isovolemic hemodilution to Hb of 5 g per dL and self-scored their energy level at various Hb concentrations. Heart rate and blood pressure were also measured. For controls, measurements of each subject were made during a comparable period of rest without hemodilution. RESULTS: During acute isovolemic hemodilution, energy levels decreased progressively and were lower at Hb of 7, 6, and 5 g per dL than at baseline (p<0.01) or in control sessions (p<0.05). The energy level was lower at Hb 7 g per dL than at 14 ( p = 0.005), lower at Hb 6 g per dL than at 7 (p = 0.01), and lower at Hb 5 g per dL than at 6 (p =0.01). Energy levels rose and were not different from baseline or control levels after transfusion of all autologous RBCs. Similarly, median heart rate increased with hemodilution to Hb of 7, 6, and 5 g per dL and decreased with transfusion of autologous RBCs. Supine blood pressure did not decrease with isovolemic hemodilution. CONCLUSION: In resting, young, healthy humans, acute isovolemic anemia to Hb levels of 7, 6, and 5 g per dL results in decreased self-scored energy levels and in an increase in heart rate but not in hypotension. Changes in energy and heart rate are reversible with the transfusion of autologous RBCs.

Acute Disease↗
PubMed2000

Electrocardiographic ST-segment changes during acute, severe isovolemic hemodilution in humans.

BACKGROUND: Controversy exists regarding the lowest blood hemoglobin concentration that can be safely tolerated. The authors studied healthy resting humans to test the hypothesis that acute isovolemic reduction of blood hemoglobin concentration to 5 g/dl would produce an imbalance in myocardial oxygen supply and demand, resulting in myocardial ischemia. METHODS: Fifty-five conscious healthy human volunteers were studied. Isovolemic removal of aliquots of blood reduced blood hemoglobin concentration from 12.8 +/- 1.2 to 5.2 +/- 0.5 g/dl (mean +/- SD). Removed blood was replaced simultaneously with intravenous fluids to maintain constant isovolemia. Hemodynamics and arterial oxygen content (Cao2) were measured before and after removal of each aliquot of blood. Electrocardiographic (ECG) changes were monitored continuously using a Holter ECG recorder for detection of myocardial ischemia. RESULTS: During hemodilution, transient, reversible ST-segment depression developed in three subjects as seen on the electrocardiogram during hemodilution. These changes occurred at hemoglobin concentrations of 5-7 g/dl while the subjects were asymptomatic. Two of three subjects with ECG changes had significantly higher heart rates than those without ECG changes at the same hemoglobin concentrations. When evaluating the entire study period, the subjects who had ECG ST-segment changes had significantly higher maximum heart rates than those without ECG changes, despite having similar baseline values. CONCLUSION: With acute reduction of hemoglobin concentration to 5 g/dl, ECG ST-segment changes developed in 3 of 55 healthy conscious adults and were suggestive of, but not conclusive for, myocardial ischemia. The higher heart rates that developed during hemodilution may have contributed to the development of an imbalance between myocardial supply and demand resulting in ECG evidence of myocardial ischemia. However, these ECG changes appear to be benign because they were reversible and not accompanied by symptoms.

Adult↗
PubMed2000

Reductively debrominating strains of Propionigenium maris from burrows of bromophenol-producing marine infauna.

Two novel strains of Propionigenium maris able to reductively debrominate 2,4,6-tribromophenol (TBP) to monobromophenols were isolated from marine hemichordate and polychaete burrows. These two strains, DSL-1 and ML-1, were anaerobic, non-motile rods that stained Gram-negative and required 0.05% yeast extract for growth. Strain DSL-1 fermented pyruvate and succinate to predominantly butyrate and strain ML-1 fermented glucose and succinate primarily to propionate. No inorganic terminal electron acceptors were identified. The pH and temperature optima for growth were 7.6 and 30 degrees C for strain DSL-1 and 7.0 and 32 degrees C for strain ML-1, respectively; doubling times for strains DSL-1 and ML-1 were 0.32 h and 0.30 h, respectively. Both strains required 2-3% (w/v) NaCl for optimal growth. Morphological and physiological features, as well as the results of 16S rDNA sequence analysis, showed these to be new strains of Propionigenium maris. Because they differ from the P. maris type strain (DSM 9537T) in a number of respects, including their ability to rapidly debrominate di- and tribromophenols, and in their specific habitats, the species description is amended to include these ecologically important properties.

Base Composition↗
PubMed2000

A national confidential enquiry into community acquired pneumonia deaths in young adults in England and Wales. British Thoracic Society Research Committee and Public Health Laboratory Service.

BACKGROUND: The aim of this study was to describe the frequency, causal pathogens, management, and outcome of a population of young adults who died from community acquired pneumonia (CAP). METHODS: Pneumonia deaths in England and Wales in adults aged 15-44 were identified between September 1995 and August 1996. Patients with underlying chronic illness including HIV infection were excluded. Clinical details for each case were collected from the hospital and general practitioner records. RESULTS: Death from CAP was identified in 27 previously well young adults (1.2 per million population per year). Twenty were known to have consulted a GP for this illness. Nine received antibiotics before hospital admission. A causative pathogen was identified in 17 cases (Streptococcus pneumoniae in eight). Bacteraemia was present in seven. All patients who reached a hospital ward received antibiotics (69% within two hours of admission). The British Thoracic Society antibiotic guidelines for severe CAP were followed in only 10 cases. Cardiac arrest at home or on arrival at hospital occurred in six cases, one of whom was successfully resuscitated. Of the remaining 21 patients, 71% had two or more markers of severe CAP. All 22 who were admitted reached an intensive care unit, but 11 of these required transfer to another hospital for some aspect of intensive care. One third of patients died within 24 hours of presenting to the hospital. CONCLUSIONS: Death from CAP in previously fit young adults still occurs. While some deaths might be preventable by better patient management, most are unlikely to be preventable by current management practices.

Adolescent↗
PubMed2000

Regional cerebral blood flow after cortical impact injury complicated by a secondary insult in rats.

BACKGROUND AND PURPOSE: Traumatic injury makes the brain susceptible to secondary insults. An uncomplicated mild lateral cortical impact injury (3 m/s, 2.5-mm deformation) that causes little or no permanent sequelae results in a large contusion at the impact site when the traumatic injury is complicated by a secondary insult, such as 40 minutes of bilateral carotid occlusion. METHODS: To determine whether the increased sensitivity to secondary insults in this model is caused by a vascular mechanism, cerebral blood flow (CBF) was measured with (14)C-isopropyliodoamphetamine quantitative autoradiography, and brain tissue PO(2) (PbtO(2)) was measured at the impact site and in the contralateral parietal cortex. RESULTS: In animals that underwent bilateral carotid occlusion 1 hour after the impact injury, CBF and PbtO(2) were lower at the impact site than they were in animals that had either the impact injury or the carotid occlusion alone. In the immediate area of the impact, CBF was 14+/-6 mL. 100 g(-1). min(-1) in the animals with the impact injury followed by carotid occlusion compared with 53+/-24 mL. 100 g(-1). min(-1) in the animals with the impact injury alone and 74+/-14 mL. 100 g(-1). min(-1) in the animals with the carotid occlusion alone (P<0.001). At the time of this very low CBF value in the animals with the carotid occlusion after the impact injury, PbtO(2) at the impact site averaged 1.3+/-1.6 mm Hg and was <3 mm Hg in 5 of the 6 animals. In contrast, PbtO(2) in the animals with the impact injury alone averaged 9.3+/-2.9 mm Hg, and none of the animals had a PbtO(2) of <3 mm Hg (P=0.008). CONCLUSIONS: The CBF and PbtO(2) findings in this model suggest that the reduced CBF after traumatic injury predisposes the brain to secondary insults and results in ischemia when confronted with a reduction in cerebral perfusion pressure.

Animals↗
PubMed2000

Facial prosthetics: techniques used in the retention of prostheses following ablative cancer surgery or trauma and for congenital defects.

The retention of facial prostheses is a major factor influencing the successful outcome of rehabilitative treatment following ablative cancer surgery or trauma and for the prosthetic replacement of congenitally absent tissue. Since the sixteenth century to the present day, facial prosthetic devices have been retained by methods including adhesives and spectacle frames. The introduction of the Branemark extra oral implant system enhanced the stability of life-like prostheses thus giving patients more confidence in their use. This paper outlines the retention systems commonly used at the authors unit and the benefits gained by the use of implants to retain facial prostheses. The use of a single stage surgical technique instead of the usual two stage procedure is detailed.

Adolescent↗
PubMed1999

SB-236057, a selective 5-HT1B receptor inverse agonist, blocks the 5-HT human terminal autoreceptor.

A novel compound, SB-236057 (1'-ethyl-5-(2'-methyl-4'-(5-methyl-1,3,4-oxadiazol-2-yl)biphenyl- 4-carbonyl)-2,3,6,7-tetrahydrospiro[furo[2,3-f]indole-3,4'-piperid ine]) has been shown to have high affinity for human 5-hydroxytryptamine1B (5-HT1B) receptors (pKi = 8.2) and displays over 75 or more-fold selectivity for the human 5-HT1B receptor over other 5-HT receptors, including the human 5-HT1D receptor, and a range of other receptors, ion channels and enzymes. In functional studies using [35S]GTPgammaS binding, SB-236057 displayed negative intrinsic activity (pEC50 = 8.0) at human 5-HT1B receptors stably expressed in Chinese Hamster Ovary (CHO) cells and caused a rightward shift of agonist concentration response curves consistent with competitive antagonism (pA2 = 8.9). SB-236057 potentiated [3H]5-HT release from electrically stimulated guinea pig or human cortical slices. SB-236057 also abolished the inhibitory effect of exogenously superfused 5-HT on electrically-stimulated release from slices of the guinea pig cortex. These studies using SB-236057 confirm that, in both the guinea pig and human cerebral cortex, the terminal 5-HT autoreceptor is of the 5-HT1B subtype.

Animals↗