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Biomedical subjects

D Owens

Publications and source records attributed to D Owens.

At least 127 records · Page 7Linked to original sources
PubMed1990

Lipoprotein composition in the alloxan-diabetic rabbit.

This study investigates the lipoprotein abnormalities in the alloxan-diabetic rabbit maintained on a standard chow diet. Poorly-controlled diabetic rabbits had elevated levels of triglyceride and phospholipid (reflected in all lipoprotein fractions) and cholesterol (reflected in the very low density and high density lipoprotein fractions) compared with well-controlled and non-diabetic rabbits. The importance of diabetic control in these changes was emphasized by the observation of a positive correlation between weight loss and serum triglyceride (rs = 0.62, p less than 0.02), cholesterol (rs = 0.65, p less than 0.01) and phospholipid (rs = 0.56, p less than 0.05). The lipoprotein fractions of the poorly-controlled rabbits were enriched with triglyceride.

Animals↗
PubMed1990

Self-harm patients not admitted to hospital.

In recent years a large proportion of self-harm patients attending hospital have not been admitted to medical or short-stay wards but have returned home directly from accident and emergency departments. A continued trend towards such a policy seems likely despite limited and conflicting evidence on its desirability. The clinical, training and epidemiological implications of changes in self-harm admission policy are outlined, together with recommendations concerning clinical audit.

Emergency Service, Hospital↗
PubMed1989

Studies on site directed mutant pig citrate synthases.

The DNAs encoding the non-mutant and mutant forms of pig citrate synthase (PCS) were subcloned into an expression system to determine their synthesis and stability in E. coli gltA- cells that are defective in bacterial citrate synthase. GltA- cells that expressed the non-mutant PCS DNA grew on defined minimal acetate media and produced a constant level of PCS (0.43 U/mg protein). In contrast, when the gltA- cells were transformed with the DNA encoding PCS mutations in His274 or Asp375 the cells did not grow on minimal acetate media. The presence of the mutant PCS proteins in E. coli was confirmed by protein blot and immunoisolation analyses using an antibody specific for porcine heart citrate synthase. The activities of the mutant PCS enzymes were two orders of magnitude less than the non-mutant enzyme in the total cell lysates. The data indicate that the active site amino acids, His274 and Asp375, are essential for the catalysis activity of citrate synthase.

Animals↗
PubMed1989

Severe mental disorder in Afro-Caribbean patients: some social, demographic and service factors.

Forty-two consecutively identified Afro-Caribbean patients with a first episode of psychosis were compared with a similar group of non-Caribbean patients. A number of differences emerged, although the same proportion of patients in each group had symptoms for 6 months or more prior to psychiatric contact. Afro-Caribbean patients showed greater delay in seeking help, more 'disturbance' later in the course of their illness and were more likely to be admitted compulsorily. The social geography of the two groups suggests that the high rates of schizophrenia and related psychoses that we previously reported cannot be explained simply by differences in area of residence at the time of presentation.

Adult↗
PubMed1988

Extraction of an infected tusk in an adult African elephant.

An 18-year-old African elephant was determined to have a nonrepairable crack in its left tusk. Treatment included extraction of the tusk, using rotational and extractional forces, and administration of antibiotics, followed by 1 year of flushing the opened tusk cavity with warm tap water. Two years after surgery, the elephant was healthy, and the tusk cavity was 80% filled with normal tissue.

Animals↗
PubMed1988

Effects of catecholamines on serum lipoproteins of normally fed and cholesterol-fed rabbits.

The effects of catecholamines on the regulation of lipoprotein metabolism have not been defined. We examined the effects of subcutaneously administered slow-release preparations of norepinephrine (2 mg/kg) and isoproterenol (0.2 mg/kg) on the serum lipoproteins of New Zealand White rabbits. Drugs or control suspension were administered daily to three groups of normally fed and three groups of cholesterol-fed rabbits, and lipoprotein analysis was performed at intervals over a 60-hour period. In the normally fed animals, norepinephrine increased the serum levels of triglyceride and phospholipid by factors of 2.4 (P less than .01) and 1.35 (P less than .05), respectively, compared with control animals at 60 hours, but had no effect on serum cholesterol. All components of serum very low density lipoproteins (VLDL: triglyceride, cholesterol, phospholipid, and protein) were significantly (P less than .01) elevated by norepinephrine in the normally fed animals. In the cholesterol-fed animals, norepinephrine at 60 hours significantly increased total serum cholesterol, triglyceride, and phospholipid concentrations by factors of 1.7 (P less than .05), 5.0 (P less than .01), and 1.6 (P less than .05), respectively, compared with controls. The norepinephrine effects in these animals was due to significant elevation of total VLDL and low density lipoproteins (LDL) and all their elemental components. Isoproterenol produced no significant effect on serum lipoprotein levels in the normally fed rabbit, but in cholesterol-fed animals it produced a rise in total serum VLDL and LDL triglyceride concentrations compared with controls at 60 hours. These data demonstrate that catecholamines are involved in the regulation of lipoprotein metabolism.

Animals↗
PubMed1988

A prospective study of severe mental disorder in Afro-Caribbean patients.

Several previous studies have reported increased rates of schizophrenia among Afro-Caribbean immigrants, although doubt has been cast upon the value of case-note diagnoses and retrospective case-finding. A prospective study was therefore undertaken, including all patients of Afro-Caribbean ethnic origin with a first onset psychosis presenting to the psychiatric services from a defined catchment area. Utilizing several diagnostic classifications, rates for schizophrenia were found to be substantially increased in the Afro-Caribbean community, and especially in the 'second generation' British born. Mode of onset and symptom profiles of psychoses suggest that atypical syndromes, and by implication 'misdiagnoses', do not account for reported higher rates of schizophrenic illness in these patients.

Adolescent↗
PubMed1987

Plasma catecholamines and lipoproteins in chronic psychological stress.

Changes in plasma catecholamines, lipoproteins and dietary intake were examined in 13 medical students during a 3-month period prior to their examinations, and in 12 controls. In the medical students mean +/- s.e.(mean) plasma cholesterol increased over the study period (3.98 +/- 0.16 v. 4.26 +/- 0.16 mmol/l, P less than 0.05) and this was reflected by a rise in low-density lipoprotein cholesterol (2.53 +/- 0.15 v. 2.71 +/- 0.17 mmol/l, P less than 0.05). Both supine adrenaline (0.45 +/- 0.05 v. 0.70 +/- 0.07 nmol/l, P less than 0.01) and noradrenaline (2.74 +/- 0.18 v. 3.40 +/- 0.31 nmol/l, P less than 0.05) increased over this period. Apart from a decline in the modest alcohol consumption (9.1 +/- 3.45 v. 2.6 +/- 1.4 g/day, P less than 0.02) there was no change in dietary intake in the medical students. There were no significant changes in plasma catecholamines, lipoproteins or dietary intake in control subjects over the study period. Changes in catecholamines and lipoproteins occurring in association with chronic psychological stress may contribute to the increased coronary heart disease mortality associated with Type A behaviour and stressful life events.

Adult↗
PubMed1985

Quantitative evaluation of the dermal vasculature of diabetics.

The dermal microvasculature has been compared in 51 diabetics and 51 matched non-diabetic controls using tissue measurement techniques and functional assessments of blood vessel reactivity. Blood vessel walls were thicker in different groups of diabetics than the controls (p less than 0.01) but the degree of thickness did not differ between patients with insulin-dependent diabetes mellitus and those with non-insulin-dependent diabetes mellitus or between diabetics with and without vascular complications. Vascular lumina were narrower in diabetics than in controls (p less than 0.01) and diabetics with vascular complications had a greater reduction in luminal area than those without such complications (p less than 0.001) but the luminal area did not differ between the insulin-dependent and the non-insulin-dependent groups. The luminal perimeter was also reduced in the diabetic group compared to controls. The weal and flare response to intracutaneous histamine acid phosphate (50 micrograms) was markedly decreased (p less than 0.001) in diabetic subjects compared with controls, as was the response to a topically applied vasodilator (Transvasin). The degree of reduction did not differ between patients with insulin-dependent diabetes mellitus and those with the non-insulin-dependent disease but diabetics with vascular complications show impaired responses as compared to those without. The maximum increase in skin temperature on the volar surface of the right middle finger during a period of reactive hyperaemia following 3 min of cuff-induced ischaemia was also markedly decreased in diabetics compared with control subjects. It did not differ between those with insulin-dependent diabetes mellitus and those with the non-insulin-dependent disease but did between diabetics with vascular complications as compared with those without. This study confirms that the cutaneous vasculature of diabetics differs markedly from that of matched control subjects. The results also indicate that there are significant differences between diabetics with vascular complications and those without. The quantitative approaches adopted may have predictive value.

Adult↗
PubMed1984

The effects of hypocapnia on intracellular pH and bicarbonate.

The intracellular pH (pHi) and bicarbonate concentration ([HCO3-]icw) of cardiac and skeletal muscles were monitored during respiratory alkalosis in order to further elucidate the homeostatic processes which operate in these tissues to ameliorate deviations from normal acid-base status. Rats were mechanically hyperventilated to induce hypocapnia, pHi was determined by the DMO method, and [HCO-3]icw was calculated from the Henderson-Hasselbalch equation using pHi and the partial pressure of carbon dioxide of vena caval blood. A significant intracellular alkalosis occurred in both cardiac and skeletal muscles during hypocapnia, but the changes in pHi were less in the heart than in skeletal muscle. The decreases in cardiac [HCO-3]icw were greater than those attributable to the physicochemical buffering of the heart. These data are consistent with an intramyocardial source of protons other than physicochemical buffering during respiratory alkalosis. The decreases in skeletal muscle [HCO-3]icw were less than those due to physicochemical buffering. These data are consistent with a net extrusion from skeletal muscles cells of the protons derived from physicochemical buffering during respiratory alkalosis.

Acid-Base Equilibrium↗
PubMed1981

A pulse method of measuring respiratory system compliance in ventilated patients.

We describe a method of measuring total static respiratory system compliance (Crs) in ventilated patients during inflation, which appears to detect relaxation of respiratory muscles and does not require an end-inspiratory pause or disconnection of a constant-flow intermittent mandatory ventilation (IMV) circuit. Flow is measured with a pneumotachometer attached to the endotracheal tube. Transthoracic pressure is taken as the difference between mouth pressure measured at the proximal pneumotachometer port and body surface (atmospheric) pressure. Flow and transthoracic pressure are displayed on separate channels of a strip chart recorder. The ventilator is adjusted to deliver a constant rule of air flow. When inflation begins, the pressure tracing shows an initial step rise related to the flow resistance of the subject followed by a section with a slower rise and a constant slope. Respiratory system compliance is calculated by dividing the flow rate in L/sec by the slope of the pressure tracing in cm H2O/sec. Pulse Crs was compared with static Crs measured with an end-inspiratory pause in nine subjects receiving mechanical ventilation. Correlation between pulse Crs and static Crs in nine ventilated patients was highly significant (4 = .997, pulse Crs = 1.00 static Crs + 0.001). We conclude that with the pulse method, one can measure static Crs during inflation without an inspiratory pause and without disconnecting an IMV circuit.

Adult↗
PubMed1980

Substituted 6,7-dihydroimidazo[1,2-a]purin-9(4H)-ones.

The synthesis of a series of substituted 6,7-dihydroimidazo[1,2-a]purin-9(4H)-ones is described. Several members of the series exhibit enhanced antiallergic and bronchodilator activity and reduced side effects as compared to theophylline. Structure-activity relationships and metabolic considerations are discussed for the series. Analogues substituted with a 4-(4-chlorobenzyl) moiety, such as 33 and 40, shown an optimal balance of antiallergic and bronchodilator activity and are of particular interest. Compound 33 is significantly more potent than theophylline against both metacholine- and antigen-induced bronchospasms, does not affect spontaneous motor activity, and shows minimal cardiovascular effects in the rat.

Animals↗
PubMed1980

Molecular forms of gastrin in peptic ulcer: comparison of serum and tissue concentrations of G17 and G34 in gastric and duodenal ulcer subjects.

We have studied the relationships between the main molecular forms of gastrin (G17 and G34) in the serum, antral and duodenal mucosa of duodenal (DU) and gastric (GU) ulcer patients. Fasting serum G17 was similar in both DU and GU (about 6 pmol/l) and in both groups increased about three-fold with feeding. In contrast, basal serum G34 was significantly higher in GU (29 pmol/l) than in DU (12 pmol/l) and the peak post prandial increase over basal of G34 was also higher in GU (57 pmol/l) compared with DU (10 pmol/l). In sharp contrast, in the same groups of DU and GU patients mean total antral gastrin concentrations were similar (about 12 nmol/g), and in both groups 95% of antral gastrin was G17, most of the remainder being G34. In both groups total duodenal gastrin concentrations were about 20% those in antral mucosa and about 70% of duodenal gastrin was attributable to G34. The higher serum G34 in GU could therefore be explained by increased secretion of duodenal gastrin, but further work is needed to examine whether there might also be preferential secretion of antral G34 in GU, or a difference in the metabolism (or volume of distribution) of gastrin variants in GU and DU.

Adult↗
PubMed1978

The use of fluphenazines in a continuing-care program.

The author describes his experience in using long-acting injectable fluphenazines with chronic schizophrenic patients in a continuing-care program in San Diego County. He has found the drug to be economical, long-lasting in therapeutic effect, and less likely than other drugs to produce serious side-effects, particularly tardive dyskinesia. In addition, use of injectables makes it possible to avoid depending on untrained operators of residential facilities to see that the patients take their drugs.

California↗