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Biomedical subjects

D Allen

Publications and source records attributed to D Allen.

At least 55 records · Page 3Linked to original sources
PubMed1990

DNA index, S-phase fraction, histological grade and prognosis in breast cancer.

DNA index and S-phase fraction (SPF) were measured by flow cytometry on paraffin embedded tissue from 140 primary breast tumours. The results of DNA analysis were compared with the size, degree of axillary node involvement, histological grade and steroid receptor content of the tumours, as well as with the patients' subsequent clinical course. Forty-four (31.4%) of the 140 tumours were diploid. S-phase fraction was evaluable for 134 (95.7%). The median SPF of the whole population was 7.1%, with diploid tumours having a significantly lower median SPF (3.2%) than aneuploid (10.1%, P less than 0.001). Both aneuploidy (P = 0.002) and high SPF (P less than 0.001) were strongly associated with high histological grade. There was no significant association between either DNA ploidy or SPF and tumour size, nodal status or steroid receptor content. An SPF below the median was strongly associated with better relapse-free survival (P = 0.008), overall survival (P = 0.004) and survival after relapse (P less than 0.001). Ploidy did not correlate significantly with clinical course. Multivariate analysis using the Cox model suggested that, while SPF gave prognostic information independent of tumour size or nodal status, this independent significance was lost when histological grade was included in the analysis.

Adult↗
PubMed1990

Evaluation of a special behaviour unit for people with mental handicaps and challenging behaviour.

A descriptive evaluation is provided of a hospital-based unit for people with mental handicaps and challenging behaviours. The characteristics of clients admitted to the unit over a 15-month period are described, together with admission and discharge patterns, and treatment interventions undertaken. The progress of four clients is studied in detail via single-case studies. While reductions in levels of challenging behaviour occurred during admission, these changes were not generally maintained at follow-up. Implications for future service design are discussed.

Adult↗
PubMed1990

Day hospital care.

Explore the source record for details and available documents.

Consumer Behavior↗
PubMed1990

Evaluation of equine digital Starling forces and hemodynamics during early laminitis.

A carbohydrate overload model was used in 8 horses to evaluate Starling forces and hemodynamics of the digit during the prodromal stage of acute laminitis. A pump-perfused extracorporeal digital preparation was used to evaluate blood flow, arterial pressure, venous pressure, capillary pressure, isogravimetric capillary filtration coefficient, osmotic reflection coefficient, and vascular compliance. From these data, pre- and postcapillary resistances and pre- to postcapillary resistance ratios were determined. Vascular and tissue oncotic pressures were estimated from plasma and lymph protein concentrations, respectively. The osmotic reflection coefficient, an estimation of capillary permeability, was determined by means of the lymph protein wash-down technique. Using the collected data, tissue pressure in the digit was calculated by use of the Starling equation. In the isolated digit, mean isogravimetric capillary pressure was 55.13 mm of Hg, mean plasma and lymph oncotic pressures were 22.29 mm of Hg and 7.2 mm of Hg, respectively, the mean osmotic reflection coefficient was 0.66, the mean capillary filtration coefficient was 0.003 ml/min/mm of Hg/100 g, and mean interstitial fluid pressure was 44.82 mm of Hg. The high capillary pressure appeared to be caused by high vascular resistance from the venous side, predisposing to enhanced capillary filtration and interstitial fluid accumulation.

Animals↗
PubMed1990

Evaluation of coagulation and fibrinolysis during the prodromal stages of carbohydrate-induced acute laminitis in horses.

The balance of coagulation and fibrinolysis was studied in 15 horses during the prodromal stages of acute laminitis induced by carbohydrate overload. Progression of the disease was stopped 12 to 24 hours before the expected onset of lameness in trial 1 (8 horses) and at the onset of lameness in trial 2 (7 horses). The end points in each trial were identified by specific changes in blood pressures (trial 1) and by changes in pulse, rectal temperature, and arterial pressure (trial 2) that were anticipated on the basis of original description of the experimental model. Blood samples for hemostasis evaluation were collected before and after carbohydrate overload in trial 1 and after carbohydrate overload in trial 2. Significant changes were not detected in platelet count, mean platelet volume, prothrombin time, activated partial thromboplastin time, fibrinogen concentration, plasminogen concentration, alpha-2-antiplasmin, antithrombin III, protein C, thromboxane B2, or fibrin(ogen) degradation product concentration. We concluded that an imbalance in coagulation and fibrinolysis is not pathogenic in the onset of experimentally induced equine acute laminitis. Because several test methods used to evaluate hemostasis in these horses were new, reference values for 34 healthy adult horses were established.

Animals↗
PubMed1990

Effect of endotoxin administration on equine digital hemodynamics and starling forces.

Using a pump-perfused extracorporeal isolated digital preparation, the effects of a 30-minute infusion of either saline solution (control) or endotoxin on equine digital hemodynamics and microvascular function were determined. Digital blood flow and arterial, venous, and capillary pressures were recorded at 15-minute intervals for 150 minutes. From these data, total vascular resistance and pre- and postcapillary resistances were calculated. Isogravimetric capillary filtration coefficient, vascular compliance, and the osmotic reflection coefficient were determined after the last hemodynamic measurements were taken. Changes in hemodynamic values of control equine digits were not observed. During the 120 minutes after infusion of endotoxin, digital blood flow decreased 43%, and total vascular resistance increased 89%. Precapillary resistance increased 122%, but postcapillary resistance did not change significantly. Changes in vascular compliance or the capillary filtration coefficient were not observed in response to either treatment. The osmotic reflection coefficient, an index of permeability, did not differ significantly between digits of the endotoxin-treated and control groups. These data indicate that the increase in vascular resistance during endotoxemia may have been attributable to arterial/arteriolar constriction and that neither the permeability nor the surface area of the exchange vasculature within the digit was significantly affected by endotoxin. Although marked alterations in vascular function are seen after administration of endotoxin, these changes do not parallel those documented in association with experimentally induced laminitis.

Animals↗
PubMed1990

Hemodynamic responses of the equine digit to intravenous and digital arterial infusion of dopamine.

In 6 adult horses anesthetized with pentobarbital, the hemodynamic responses of the equine digit to infusion of dopamine were evaluated by use of an isolated extra corporeal pump perfused digital preparation. Digital blood flow was maintained at a constant rate that was independent of systemic hemodynamic changes. Three sequential experiments were performed on each horse. In the first experiment (n = 6), dopamine was infused IV at rates of 1.0, 2.5, and 5.0 micrograms/kg/min. For the second experiment (n = 5), dopamine (400 micrograms/ml) was infused into the digital artery at the rates of 0.07, 0.7, and 1.2 ml/min. The third experiment (n = 5) consisted of a 5-minute intra-arterial infusion of phentolamine followed by the intra-arterial infusion of dopamine while continuing the infusion of phentolamine. Digital venous, arterial, and capillary pressures, total digital vascular resistance, and precapillary to postcapillary resistance ratios were determined in each experiment. Systemic infusion of dopamine did not induce changes in the hemodynamics of the digital vasculature. Digital arterial infusion of dopamine alone resulted in a dose-dependent increase in arterial pressure, total digital vascular resistance, and an increase in the precapillary to postcapillary resistance ratio. Phentolamine attenuated the vasoconstrictive response elicited by intra-arterial infusion of dopamine.

Animals↗
PubMed1989

The interaction between Cu(I) superoxide dismutase and hydrogen peroxide.

The interaction between superoxide dismutase (SOD) and peroxide, under anaerobic conditions in the presence of an OH radical scavenger, formate, and an indicator, nitro blue tetrazolium, involves five reactions and an equilibrium: (table; see text) Reaction 3 occurs at a rate that is proportional to both peroxide and enzyme with no kinetic evidence for any intermediate peroxide-enzyme complex. Rate studies as a function of pH corroborate previously published work (Fuchs, H. J. R., and Borders, C. L., Jr. (1983) Biochem Biophys. Res. Commun. 116, 1107-1113; Blech, D. M., and Borders, C. L., Jr. (1983) Arch. Biochem. Biophys. 224, 579-586) suggesting that HO2-, and not H2O2, is the active species in this system: k(HO2- + superoxide dismutase-Cu+) = 2.6 x 10(3) M-1 s-1. Evidence is presented which suggests that HO2-, like O2-, reacts at rates that are affected by the electrostatic forces of the enzyme.

Hydrogen Peroxide↗
PubMed1989

Breeding soundness of beef bulls after circumcision: 33 cases (1980-1986).

Case records of 33 beef bulls that had preputial prolapses and underwent circumcisions were reviewed. Data retrieved included age, breed, duration of preoperative medical treatment, complications of surgery, length of time from surgery to first breeding, ability of bull to copulate, duration of active breeding, and complications resulting in breeding unsoundness. The mean age of all bulls was 3.5 years (1 to 7 years). Breeds represented included Santa Gertrudis (n = 13), Beefmaster (n = 8), Brangus (n = 7), Brahman (n = 4), and Angus (n = 1). The mean duration of medical treatment before surgery for all bulls was 16.4 days (2 to 38 days). There was no statistically significant difference between the mean duration of medical treatment before surgery between bulls that became breeding sound (16 days), compared with those that were breeding unsound (19 days). However, bulls requiring more than 14 days of medical treatment before surgery were approximately 3 times (relative risk, 2.8) more likely to develop postoperative complications than those bulls requiring 14 days of treatment or less. Eleven bulls (33%) developed one or more postoperative complications. The complications resolved in 4 bulls, but 7 were never able to breed. Of these 7 bulls, 4 had problems directly related to the circumcision, 2 had extensive fibrosis of the prepuce already present at surgery, and 1 was discharged from the hospital with no apparent complications but was never able to breed. Twenty-five of the 33 bulls (76%) were breeding sound for 1 or more years after surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Outpatient treatment of 'crack' cocaine smoking with flupenthixol decanoate. A preliminary report.

"Crack" cocaine abuse often produces severe cocaine dependence that is refractory to available pharmacological and outpatient psychotherapeutic treatments. We conducted two preliminary investigations evaluating the efficacy of flupenthixol decanoate, a depot xanthene requiring infrequent intramuscular administration, in the treatment of cocaine withdrawal. Ten outpatient crack cocaine smokers with poor prognoses were administered flupenthixol decanoate in an open-label, open-ended trial. Flupenthixol decanoate was well tolerated and appeared to decrease cocaine craving and use markedly and rapidly, producing a 260% increase in the average time retained in treatment among these subjects. These promising but preliminary data, combined with the magnitude of problems presented by crack, warrant rapid, expanded double-blind assessment of flupenthixol decanoate in cocaine-abuse treatment.

Adult↗
PubMed1989

Non-random migration of CD4 and CD8 T cells: changes in the CD4: CD8 ratio and interleukin 2 responsiveness of efferent lymph cells following in vivo antigen challenge.

In this investigation we have examined some of the cellular and molecular changes in efferent lymph that drains from an antigen-stimulated peripheral lymph node. Resting efferent lymph is characterized by a higher percentage of CD4+ cells and consequently, a higher CD4/CD8 ratio than peripheral blood. Following antigen stimulation of a cannulated peripheral lymph node in antigen-primed sheep, the percentage of CD4+ cells in efferent lymph increases above the resting level during days 1, 2 and 3 post antigen stimulation. This is followed on days, 3, 4, and 5 after antigen stimulation by an increase in the percentage of CD8+ cells above the resting level which occurs as the percentage of CD4+ cells returns to the resting level. These changes cause the CD4/CD8 ratio to first increase above the resting value during the CD4 phase and then decrease below the resting value during the CD8 phase. During the CD4 phase a lymphokine activity is present in cell-free lymph fluid. Lymph fluid collected at this time supports the proliferation of activated T cells. Supernatants generated from efferent cells collected at a similar time and cultured in vivo for 24 h without any further stimulation are capable of releasing this material. During the CD8 phase cells expressing functional interleukin(IL)2 receptors appear in lymph fluid. The data suggests a sequential exit of T cell subsets from an antigen-stimulated lymph node and that the appearance of IL2-like activity and IL2-responsive cells in efferent lymph fluid are temporally distinct events.

Animals↗
PubMed1989

Pathophysiology of acute laminitis.

This article reviews research findings relating to the pathophysiology of acute laminitis in horses. The data presently available suggest that the onset of the condition may be due to constriction of the postcapillary vessels in the digit, leading to increased capillary hydrostatic pressure and movement of fluid into the interstitial space.

Acute Disease↗