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Biomedical subjects

K Whyte

Publications and source records attributed to K Whyte.

14 recordsLinked to original sources
PubMed2004

Prevalence of chronic renal failure in the diabetic population at the University Hospital of the West Indies.

The prevalence of chronic renal failure (CRF) in 460 patients with diabetes mellitus attending the diabetic outpatient clinic at the University Hospital of the West Indies in Jamaica was determined from a review of medical records. The prevalence of CRF was 10% (39/386) in the diabetic clinic population. Significant positive associations with CRF were found with male gender (20/98, 20% vs 19/287, 7%; odds ratio (OR), 3.24; p = 0.001); age 60 years and older (22/162; 14% vs 17/221, 8%; OR, 2.01; p = 0.04); fasting blood glucose concentrations exceeding 8.0 mmol/L (22/162, 13% vs 12/182, 7%; OR, 2.08; p = 0.05); the presence of significant proteinuria as a marker for outcome (13/39, 33% vs 48/346, 14%; OR, 3.60; p = 0.02) and peripheral vascular disease (6/20, 30% vs 139/386, 10%; OR, 4.75; p = 0.005). The prevalence of CRF did not differ significantly between patients with Type 1 and Type 2 diabetes mellitus. Also, the presence of CRF was not significantly associated with duration of diabetes mellitus, type of hypoglycaemic agents used, or history of hypertension. However, the presence of persistent proteinuria was significantly associated with duration of diabetes mellitus exceeding five years (46/255, 17% vs 11/149, 7%; OR, 2.52; p = 0.005) and a history of hypertension (41/235, 17% vs 20/198, 10%; OR, 1.88; p = 0.03) but not with age or gender. This study emphasizes the need to evaluate patients with diabetes mellitus for renal impairment so that intervention strategies may be adopted early to delay progression to endstage renal disease.

Adolescent↗
PubMed2003

UK Back pain Exercise And Manipulation (UK BEAM) trial--national randomised trial of physical treatments for back pain in primary care: objectives, design and interventions [ISRCTN32683578].

BACKGROUND: Low back pain has major health and social implications. Although there have been many randomised controlled trials of manipulation and exercise for the management of low back pain, the role of these two treatments in its routine management remains unclear. A previous trial comparing private chiropractic treatment with National Health Service (NHS) outpatient treatment, which found a benefit from chiropractic treatment, has been criticised because it did not take treatment location into account. There are data to suggest that general exercise programmes may have beneficial effects on low back pain. The UK Medical Research Council (MRC) has funded this major trial of physical treatments for back pain, based in primary care. It aims to establish if, when added to best care in general practice, a defined package of spinal manipulation and a defined programme of exercise classes (Back to Fitness) improve participant-assessed outcomes. Additionally the trial compares outcomes between participants receiving the spinal manipulation in NHS premises and in private premises. DESIGN: Randomised controlled trial using a 3 x 2 factorial design. METHODS: We sought to randomise 1350 participants with simple low back pain of at least one month's duration. These came from 14 locations across the UK, each with a cluster of 10-15 general practices that were members of the MRC General Practice Research Framework (GPRF). All practices were trained in the active management of low back pain. Participants were randomised to this form of general practice care only, or this general practice care plus manipulation, or this general practice care plus exercise, or this general practice care plus manipulation followed by exercise. Those randomised to manipulation were further randomised to receive treatment in either NHS or private premises. Follow up was by postal questionnaire one, three and 12 months after randomisation. The primary analysis will consider the main treatment effects before interactions between the two treatment packages. Economic analysis will estimate the cost per unit of health utility gained by adding either or both of the treatment packages to general practice care.

Adult↗
PubMed2002

Ambulatory oxygen improves quality of life of COPD patients: a randomised controlled study.

It is unknown whether acute response to ambulatory oxygen (O2) predicts longer term improvement in health-related quality of life (HRQL) in chronic obstructive pulmonary disease (COPD) patients. The aims of this study were 1) to assess the short-term clinical impact, as determined by HRQL, of ambulatory O2 in a 12-week, double-blind, randomised crossover study of O2 (versus cylinder compressed air) of dyspnoeic but not chronically hypoxic COPD patients with exertional desaturation < or = 88% (n=41), and 2) to determine whether either baseline characteristics or acute response to O2 predicts short-term (12 weeks) response. Primary outcome measures were Chronic Respiratory Questionnaire (CRQ), Hospital Anxiety and Depression scale and the short form (SF)-36. Improvements were seen in all domains of the CRQ for cylinder O2 compared with cylinder air. Significant improvements were also noted in anxiety and depression and in certain domains of the SF-36. There were 28 (68%) acute responders to cylinder O2 (defined as increase in 6-min walk > or = 54 m or decrease in post-Borg dyspnoea > or = 1) and 23 (56%) short-term responders (defined as clinically significant improvement in CRQ). However, acute and short-term responses were not correlated with no predictors of short-term response identified. At study completion, 14 (41%) of acute or short-term responders did not want to continue therapy, with 11 citing poor acceptability or tolerability. Short-term ambulatory oxygen is associated with significant improvements in health-related quality of life. These benefits cannot be predicted by baseline characteristics or acute response. Despite acute or short-term response, a substantial proportion of patients declined ambulatory oxygen.

Aged↗
PubMed2001

HRT and breast changes.

S K is a sensible, fit 53 year old with irritating menopausal symptoms who wants to discuss hormone replacement therapy (HRT). She has had a previous mammogram which described moderately dense breasts with only fair visibility for discrete lesions. More recently she had a screening mammogram at BreastScreen, and received a routine 'all clear' letter. You believe that HRT can relieve her symptoms.

Breast↗
PubMed2000

Craniofacial form and obstructive sleep apnea in Polynesian and Caucasian men.

STUDY OBJECTIVES: This aim of this study was to determine the relative contributions of craniofacial form and anthropometric factors to obstructive sleep apnea (OSA) in two different racial groups, both markedly obese and with a similar mean respiratory disturbance index (RDI). DESIGN: A cross-sectional study of New Zealand Maori (Polynesian) and European (Caucasian) men with RDI> or =15, using lateral and postero-anterior cephalometric radiography. SETTING: N/A. PATIENTS OR PARTICIPANTS: N/A. MEASUREMENTS AND RESULTS: Measurements of facial and cranial width, length and height, airway size, stature, weight, body mass index (BMI), neck circumference, RDI, and age were obtained. The Polynesian men had, on average, a greater neck circumference than the Caucasian men. There were no significant differences in age, weight, BMI or RDI between the two groups. The Polynesian men also had broader craniofacial skeletons, larger and more prognathic mandibles, greater neck extension, and some larger airway dimensions than the Caucasian men. In the Polynesian men, the width of the bony nasal aperture was positively associated with RDI, and mandibular prognathism was negatively associated with RDI. In contrast, in the Caucasian men only neck circumference was positively associated with RDI, while the retropalatal airway was negatively associated with RDI. CONCLUSIONS: The results indicate that OSA in these two racially distinct groups is due to different etiological factors. Small reductions in mandibular prognathism and a wider bony nasal aperture were major factors associated with OSA in Polynesians. On the other hand, in the Caucasian group OSA was associated with a larger neck circumference and a reduced retropalatal airway size.

Anthropometry↗
PubMed2000

Pulmonary embolism.

Explore the source record for details and available documents.

Diagnosis, Differential↗
PubMed1998

Human autoantibodies specific for the alpha1A calcium channel subunit reduce both P-type and Q-type calcium currents in cerebellar neurons.

The pharmacological properties of voltage-dependent calcium channel (VDCC) subtypes appear mainly to be determined by the alpha1 pore-forming subunit but, whether P-and Q-type VDCCs are encoded by the same alpha1 gene presently is unresolved. To investigate this, we used IgG antibodies to presynaptic VDCCs at motor nerve terminals that underlie muscle weakness in the autoimmune Lambert-Eaton myasthenic syndrome (LEMS). We first studied their action on changes in intracellular free Ca2+ concentration [Ca2+]i in human embryonic kidney (HEK293) cell lines expressing different combinations of human recombinant VDCC subunits. Incubation for 18 h with LEMS IgG (2 mg/ml) caused a significant dose-dependent reduction in the K+-stimulated [Ca2+]i increase in the alpha1A cell line but not in the alpha1B, alpha1C, alpha1D, and alpha1E cell lines, establishing the alpha1A subunit as the target for these autoantibodies. Exploiting this specificity, we incubated cultured rat cerebellar neurones with LEMS IgG and observed a reduction in P-type current in Purkinje cells and both P- and Q-type currents in granule cells. These data are consistent with the hypothesis that the alpha1A gene encodes for the pore-forming subunit of both P-type and Q-type VDCCs.

Animals↗
PubMed1989

The effect of six months of daily treatment with the beta-2 agonist oral pirbuterol on pulmonary hemodynamics in patients with chronic hypoxic cor pulmonale receiving long-term oxygen therapy.

We studied the acute and long-term effect of the oral beta-2 agonist pirbuterol on pulmonary hemodynamics and right and left ventricular ejection fractions in 11 patients with stable hypoxic chronic bronchitis and emphysema who were maintained on long-term oxygen therapy. We have used a double-blind study with random allocation of patients to receive either pirbuterol or an identical-appearing placebo. Six patients received 15 mg pirbuterol thrice daily, and five patients received a similar placebo thrice daily, over a 6-month period. The first 15-mg dose of pirbuterol by mouth at the beginning of the study raised the heart rate from 84 +/- 13 to 100 +/- 16 beats/min (mean +/- SD) (p less than 0.01), and cardiac output from 5.2 +/- 0.9 to 6.4 +/- 0.8 L/min (p less than 0.01) and right ventricular ejection fraction (RVEF) from 0.28 +/- 0.10 to 0.33 +/- 0.12 (p less than 0.01) within 120 min after receiving the drug, but without significant change in the mean pulmonary arterial pressure. None of these variables changed significantly after an acute dose of placebo in another four patients. Repeated measurements after 6 months of chronic oral therapy with either pirbuterol or placebo showed that 16 h after the last 15-mg oral dose of pirbuterol or placebo, the heart rate, mean pulmonary arterial pressure, cardiac output, total pulmonary vascular resistance, and RVEF were all not significantly different from the values 6 months previously, before receiving either pirbuterol or the placebo.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Agonists↗
PubMed1987

Haemodynamic, metabolic, and lymphocyte beta 2-adrenoceptor changes following chronic beta-adrenoceptor antagonism.

We have examined the effects of 7 days treatment with beta adrenoceptor antagonists in 8 healthy volunteers in a placebo controlled, crossover study. We investigated three beta-adrenoceptor antagonists (atenolol, oxprenolol, and propranolol), which have differing profiles of selectivity and partial agonist properties (intrinsic sympathomimetic activity, ISA). We studied adrenaline-induced hypokalaemia, the vasodilator response to an infusion of adrenaline (0.06 micrograms X kg-1 X min-1 for 90 min), and lymphocyte beta 2-adrenoceptor number, determined by (-) [125I]-iodocyanopindolol binding, and measured these variables both before and after 7 days of treatment. The beta 2-mediated depressor response to adrenaline infusion was abolished by propranolol and oxprenolol but persisted after atenolol. In contrast, the hypokalaemia induced by adrenaline was abolished by all three beta-blockers. Lymphocyte beta 2-adrenoceptor number increased significantly following propranolol treatment, but not after oxprenolol for atenolol. We conclude that up-regulation of lymphocyte beta 2-adrenoceptors is dependent on beta 2-receptor blockade and is modified by ISA. The reversal of the hypokalaemic response by atenolol suggests that beta 1 receptors may contribute to the former effect. Alternatively, since different populations of beta 2-adrenoceptors differ in their susceptibility to antagonists there may also be differences in agonist coupling to beta 2-responses between tissues.

Adrenergic beta-Antagonists↗
PubMed1986

Desensitization of platelet alpha 2-adrenoceptors after short term infusions of adrenoceptor agonist in man.

The effect of intravenous infusion of catecholamines and related drugs on human platelet alpha 2-adrenoceptor number and function was investigated. Short (60-120 min) infusions of catecholamines with alpha 2 agonist activity in vivo produced attenuation of the platelet responses to adrenaline in vitro. This desensitization was specific for the adrenaline induced aggregatory response. The maximum number of [3H]yohimbine binding sites on platelets was not altered by adrenaline infusion. The ability of adrenaline to reduce platelet cyclic AMP levels was significantly reduced after the infusions. Acute infusions of alpha 2-adrenoceptor agonists may alter the coupling of the platelet alpha 2-adrenoceptor to adenylate cyclase.

Adolescent↗