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Biomedical subjects

D Crook

Publications and source records attributed to D Crook.

At least 19 recordsLinked to original sources
PubMed2006

Using the UK primary care Quality and Outcomes Framework to audit health care equity: preliminary data on diabetes management.

BACKGROUND: The incentivization of UK primary care through the Quality and Outcomes Framework (QOF) has released an unprecedented supply of data that in theory could aid health equity audit and reduce health inequalities. The current system allows for 'exception reporting' whereby patients can be excluded from calculation of payment for reasons such as failure to attend review. We speculated that such exclusions could be linked to socioeconomic deprivation. METHODS: We assessed 'exception reporting' rates for 15 diabetes indicators using 2004/05 QOF data for 49 general practitioner (GP) practices in Brighton and Hove and related it to a deprivation ranking for each practice. RESULTS: The standardized diabetes prevalence was 26% higher (P < 0.001) in the highest compared to the lowest quintile of deprivation. Correlations between 'exception reporting' and deprivation were seen for 10 of the 15 diabetes indicators (r = 0.20-0.41, P < 0.05). Practices with a more deprived patient population were more likely to report 'exceptions' for QOF indicators, although there was no such relationship with the achievement of QOF targets. CONCLUSIONS: Strategies to reduce health inequalities need to take into account that high levels of exception reporting, particularly in practices with deprived populations, may be disguising unmet need in those populations.

Appointments and Schedules↗
PubMed2006

Carriage of group B streptococcus in pregnant women from Oxford, UK.

OBJECTIVE: To investigate asymptomatic vagino-rectal carriage of group B streptococcus (GBS) in pregnant women. METHODS: Women in the final trimester of pregnancy were recruited. A single vagino-rectal swab was taken, with consent, for culture of GBS. Two microbiological methods for isolation of GBS from vagino-rectal swabs were compared. The distribution of capsular serotypes of the GBS identified was determined. Epidemiological data for a subset (n = 167) of the pregnant women participating were examined. RESULTS: 21.3% were colonised vagino-rectally with GBS. Risk factors for neonatal GBS disease (maternal fever, prolonged rupture of membranes, and preterm delivery) were present in 34 of 167 women (20.4%), and the presence of these factors correlated poorly with GBS carriage. Capsular serotypes III (26.4%), IA (25.8%), V (18.9%), and IB (15.7%) were prevalent in the GBS isolates. Selective broth culture of vagino-rectal swabs was superior to selective plate culture, but the combination of both methods was associated with increased detection of GBS (7.5%). An algorithm for the identification of GBS from vagino-rectal swabs was developed. CONCLUSIONS: GBS carriage is prevalent in pregnant women in Oxfordshire, UK. The poor correlation between risk factors and GBS carriage requires further investigation in larger groups, given that the identification of these surrogate markers is recommended to guide administration of intrapartum antibiotic prophylaxis by the Royal College of Obstetricians of the UK. A selective broth culture detected more GBS carriers than a selective plate culture.

Algorithms↗
PubMed2005

Women's perceptions of hormone replacement therapy: risks and benefits (1980-2002). A literature review.

OBJECTIVES: Many postmenopausal women are reluctant to take hormone replacement therapy (HRT) and those who do are likely to discontinue within 1 year. Setting aside the beliefs and prejudices of the prescriber, women's own perceptions of risks and benefits may influence their willingness to accept and then persevere with HRT. We conducted a systematic literature review relating women's beliefs about HRT to acceptance and adherence. METHODS: Using standard guidelines for systematic search procedures, we identified 112 papers (published during 1980-2002) from databases such as Medline, PsycINFO and the NHS and Cochrane libraries. RESULTS: Women hold both positive and negative beliefs about HRT. Their perceptions of benefits are often countered by concerns over potential adverse effects, beliefs that are sometimes at odds with the clinical evidence. The use and discontinuation of HRT are influenced more by short-term symptom relief than by considerations of long-term benefits. Many women who refuse HRT believe that the menopause is a natural event that does not warrant 'chemical' intervention. Doctors and nurses are not used to their full capacity as an education and information resource to counter the possibility of unbalanced stories in the media. CONCLUSIONS: Addressing women's preconceptions about HRT should be an important part of the process of prescribing and review. Such an approach will help ensure that a woman's decision to start or continue HRT is informed by an understanding of the known risks and benefits, rather than by myths or mistaken beliefs about the menopause or HRT.

Decision Making↗
PubMed2004

Hemostatic risk factors and insulin sensitivity, regional body fat distribution, and the metabolic syndrome.

Disturbances in the thrombotic and fibrinolytic systems are a feature of insulin resistance, obesity, and the metabolic syndrome. However, there are few studies in which these relationships have been explored in mainly asymptomatic individuals using sophisticated measures of insulin sensitivity and regional adiposity. Variables of the hemostatic system were measured in 106 men (aged 32-68 yr; body mass index, 20-34 kg/m(2)). Insulin sensitivity was measured by minimal model analysis and regional adiposity by dual energy x-ray absorptiometry. Clustering of intercorrelated variables was assessed by the statistical technique of factor analysis. Plasma levels of procoagulant factors VII and X, anticoagulant proteins C and S, and plasminogen activator inhibitor-1 correlated positively with total and percent central body fat (r = 0.25-0.38; P < 0.05) and negatively with insulin sensitivity (except protein S; r = -0.24 to -0.35; P < 0.05). On factor analysis, procoagulant factors VII and X, proteins C and S, and plasminogen activator inhibitor-1 were components of the cluster of variables that explained the greatest proportion of the variance in the data (39.2%). Other variables included in this cluster were those typical of the metabolic syndrome and also serum gamma-glutamyl transferase activity. These results suggest that factors VII and X and proteins C and S are features of the intercorrelated disturbances of the metabolic syndrome. Associations with adiposity and liver enzyme activity suggest the involvement of hepatic fat deposition.

Adipose Tissue↗
PubMed2004

Effects of low and high dose oestradiol and dydrogesterone therapy on insulin and lipoprotein metabolism in healthy postmenopausal women.

OBJECTIVE: Menopause diminishes insulin secretion and elimination, increases risk of diabetes and adversely affects lipoprotein metabolism. This study was undertaken to establish whether oral oestradiol plus dydrogesterone postmenopausal hormone therapy can modify these changes. DESIGN: Randomized prospective trial of postmenopausal women taking low dose therapy (1 mg/day oestradiol-17 beta with 5 or 10 mg/day dydrogesterone for days 17-28 of each cycle, n = 15) or high dose therapy (2 mg/day oestradiol-17 beta with 10 or 20 mg/day orally administered dydrogesterone, n = 9). MEASUREMENTS: Patients underwent measurement of glucose, insulin and C-peptide in the fasting state and during an intravenous glucose tolerance test (IVGTT) at baseline and after 12 and 24 cycles of treatment. Modelling analysis was used to derive measures of insulin secretion, elimination and sensitivity. Fasting serum lipids, lipoproteins and apolipoproteins were also measured. RESULTS: In both groups there were significant reductions in fasting glucose, insulin and C-peptide. Pancreatic insulin secretion during the IVGTT was increased by treatment (ranging from 45% to 92%, P < 0.01). Insulin elimination was increased at both the peripheral (16% to 43%, P < 0.05) and hepatic (18% to 31%, P < 0.05) levels. Insulin sensitivity was unaffected. Low density lipoprotein (LDL) cholesterol was reduced and high density lipoprotein (HDL) cholesterol increased with treatment. CONCLUSIONS: Postmenopausal hormone therapy with oestradiol plus dydrogesterone can favourably affect lipoprotein concentrations and can reverse menopause-associated changes in insulin secretion and elimination.

Adult↗
PubMed2002

Effect of postmenopausal oestradiol and dydrogesterone therapy on lipoproteins and insulin sensitivity, secretion and elimination in hysterectomised women.

OBJECTIVES: To investigate in depth the metabolic effects of oestradiol-17 beta both alone and in combination with the progestagen dydrogesterone. METHODS: Fifteen hysterectomised postmenopausal women were studied before treatment and after 24 weeks taking oestradiol-17 beta alone (2 mg per day), then following a further 6 (oestrogen-alone phase) and 12 (oestrogen plus progestagen phase) weeks with inclusion of dydrogesterone (10 mg per day for days 17-28 of each 28 day cycle). Measurements at each visit included fasting serum lipid and lipoprotein concentrations, insulin sensitivity, secretion and elimination by modelling analysis of intravenous glucose tolerance test glucose, insulin and C-peptide concentrations, body fat distribution by dual-energy X-ray absorptiometry (DXA) and arterial function by carotid artery ultrasound. RESULTS: Significant reductions were seen throughout in total and LDL cholesterol. The net reductions in total and LDL cholesterol by the end of the study were 5.8% (P<0.05) and 18.4% (P<0.001), respectively. HDL and HDL subfraction cholesterol concentrations rose during treatment with oestradiol alone, the rise being primarily in the HDL(2) subfraction (+21.6%, P<0.001). Fasting serum triglycerides rose 30% on oestradiol treatment. These increases were unaffected by the addition of dydrogesterone. Insulin sensitivity, secretion and elimination, body fat distribution and arterial function were not significantly affected at any stage of the therapy. CONCLUSIONS: The small study sample and high variability in measures of glucose and insulin metabolism may have contributed to the absence of the expected significant improvement in these parameters. Orally administered oestradiol had beneficial effects on total, LDL and HDL cholesterol which were unaffected by the addition of dydrogesterone.

Absorptiometry, Photon↗
PubMed2000

Relation of plasma lipids to insulin resistance, nonesterified fatty acid levels, and body fat in men from three ethnic groups: relevance to variation in risk of diabetes and coronary disease.

Afro-Caribbean men in the United Kingdom have a favorable lipoprotein profile and are at low risk of coronary heart disease (CHD) compared with Europeans and South Asians, but are at high risk of non-insulin-dependent diabetes mellitus (NIDDM) compared with Europeans. To investigate these differences, a cross-sectional comparison was undertaken for measures of lipoprotein metabolism, body composition, and insulin's glucoregulatory and antilipolytic actions in 92 healthy men (42 to 61 years) of Afro-Caribbean, South Asian, or European origin. Afro-Caribbean men were more insulin-resistant than Europeans (insulin sensitivity [Si], 1.96 v3.01 min(-1) x microU(-1) x mL, P < .01). They nevertheless had a more favorable lipoprotein profile, with lower levels of very-low-density lipoprotein (VLDL) cholesterol (0.21 v 0.40 mmol/L, P < .01) and triglycerides (0.34 v 0.74 mmol/L, P < .01), lower serum total triglycerides, higher high-density lipoprotein 2 (HDL2) cholesterol, and larger low-density lipoprotein (LDL) particle size. These differences were not accounted for by differences in nonesterified fatty acid (NEFA) levels, the sensitivity of suppression of NEFA levels to insulin, or body composition. South Asians were also more insulin-resistant than Europeans but had a less favorable lipoprotein profile. Afro-Caribbean men in the United Kingdom are as insulin-resistant as South Asian men but less susceptible to the lipid disturbances that characteristically accompany insulin resistance. This favorable lipid pattern may relate to more effective VLDL metabolism rather than a reduced supply of NEFA as substrate for triglyceride synthesis.

Adipose Tissue↗
PubMed2000

Outcome of invasive pneumococcal disease: a UK based study. Oxford Pneumococcal Surveillance Group.

METHODS: The records of 106 children aged less than 5 years with invasive disease caused by Streptococcus pneumoniae were reviewed. RESULTS: The clinical manifestations were meningitis (37%), upper respiratory tract infection (24%), pneumonia (19%), and occult bacteraemia (18%). One child died and seven had persisting neurological impairment. Five serotypes caused 83% of disease and 92% of the serotypes are included in the seven valent conjugate vaccines which are undergoing trials. CONCLUSIONS: These data suggest that S pneumoniae infection is associated with a low case fatality rate but substantial morbidity in the UK.

Child, Preschool↗
PubMed2000

Occlusive vascular diseases in oral contraceptive users. Epidemiology, pathology and mechanisms.

Despite being an unprecedented departure from normal physiology, the combined oral contraceptive is not only highly effective, but it also has a remarkably good safety record. Concerns over safety persist, though, particularly with regard to venous thromboembolism (VTE), stroke and myocardial infarction (MI). Epidemiological studies consistently show an increase in risk of VTE, but the results are more contentious with regard to arterial diseases. Despite 40 years of research, the mechanisms behind these adverse effects are not understood. In this review, we integrate information from published studies of the epidemiology and pathology of the occlusive vascular diseases and their risk factors to identify likely explanations for pathogenesis in oral contraceptive users. Oral contraceptives induce both prothrombotic and fibrinolytic changes in haemostatic factors and an imbalance in haemostasis is likely to be important in oral contraceptive-induced VTE. The complexity of the changes involved and the difficulty of ascribing clinical significance has meant that uncertainty persists. A seriously under-researched area concerns vascular changes in oral contraceptive users. Histologically, endothelial and intimal proliferation have been identified in women exposed to high plasma estrogen concentrations and these lesions are associated with thrombotic occlusion. Other structural changes may result in increased vascular permeability, loss of vascular tone and venous stasis. With regard to arterial disease risk, epidemiological information relating to dose effects and joint effects with other risk factors, and studies of pathology and changes in risk factors, suggests that oral contraceptive use per se does not cause arterial disease. It can, nevertheless, synergise very powerfully with subclinical endothelial damage to promote arterial occlusion. Accordingly, the prothrombotic effects of the oral contraceptive estrogen intervene in a cycle of endothelial damage and repair which would otherwise remain clinically silent or would ultimately progress - in, for example, the presence of cigarette smoking or hypertension - to atherosclerosis. Future work in this area should focus on modification of the effects of established risk factors by oral contraceptive use rather than modification of the supposed risk of oral contraceptive use by established risk factors. Attempts to understand vascular occlusion in oral contraceptive users in terms of the general features of VTE or with reference to atherosclerosis may be limiting, and future work needs to acknowledge that such occlusions may have unique features. Unequivocal identification of the mechanisms involved would contribute considerably to the alleviation of fears over vascular disease and to the development of even safer formulations.

Adult↗
PubMed1999

Tick-borne encephalitis.

Tick-borne encephalitis (TBE) is a zoonotic arbovirus infection endemic to Russia and Eastern and Central Europe. Despite being a common and serious life-threatening disease for which a mass vaccination program was implemented in Austria, there is only limited reference to this disease in the English-language literature. TBE is transmitted to humans usually by the bite of a tick (either Ixodes persulcatus or Ixodes ricinus); occasionally, cases occur following consumption of infected unpasteurized milk. Transmission is seasonal and occurs in spring and summer, particularly in rural areas favored by the vector. TBE is a serious cause of acute central nervous system disease, which may result in death or long-term neurological sequelae. Effective vaccines are available in a few countries. The risk for travelers of acquiring TBE is increasing with the recent rise in tourism to areas of endemicity during spring and summer.

Animals↗
PubMed1999

A randomised comparison of the effects of oral versus transdermal 17beta-oestradiol, each combined with sequential oral norethisterone acetate, on serum lipoprotein levels.

OBJECTIVE: To investigate the effects of oral versus transdermal 17beta-oestradiol, given in both cases with sequential addition of oral norethisterone acetate, on serum lipid and lipoprotein levels in postmenopausal women. DESIGN: Open, randomised, parallel groups study. SETTING: University Clinical Research Group. POPULATION: Sixty-four postmenopausal women with climacteric complaints who were otherwise healthy were screened. Of these, 58 fulfilled the entry criteria. METHODS: Fifty-eight postmenopausal women were randomised to receive either oral 17beta-oestradiol/oestriol (Trisequens) or transdermal 17beta-oestradiol (Estrapak) together with cyclical addition of norethisterone acetate for 48 weeks. MAIN OUTCOME MEASURES: Serum levels of total cholesterol, triglycerides, high density lipoproteins (HDL), low density lipoproteins (LDL), very low density lipoproteins (VLDL), apolipoproteins, and lipoprotein(a) at baseline, and after 46 weeks (oestrogen-alone phase), and 48 weeks (oestrogen-progestogen phase) of treatment. RESULTS: Oral oestradiol therapy did not affect serum total cholesterol levels during the oestrogen-alone phase, but during the combined phase there was a 5% fall (P < 0.05) due to a 7% decrease in LDL cholesterol levels (P < 0.01). Oral therapy also increased serum triglyceride levels by 9.4% during the oestrogen-alone phase (P < 0.05). During the combined phase of transdermal therapy, there was a 19% fall in serum triglyceride levels (P < 0.05) and a 6% fall in HDL levels (P < 0.05). Oral oestradiol reduced lipoprotein(a) levels by 31% during the oestrogen-alone phase and by 37% with norethisterone acetate addition (P < 0.05). Transdermal therapy had no significant effect on lipoprotein(a). CONCLUSIONS: Other than a minor fall in HDL3 in women receiving transdermal 17beta-oestradiol, coadministration of oral progestogen in general improved, rather than worsened, this serum lipoprotein profile.

Administration, Cutaneous↗
PubMed1998

Safety evaluation of modern oral contraceptives. Effects on lipoprotein and carbohydrate metabolism.

An ideal oral contraceptive should either be neutral as regards metabolic risk markers for arterial disease or should only change them in directions that would be expected to reduce risk. Depending on their formulation, modern low dose oral contraceptives affect systems such as hemostasis, lipoprotein metabolism, and glucose and insulin metabolism. Some of these actions would be expected to decrease the risk of arterial disease and some might be expected to increase risk. Despite these associations there is at present no justification for widespread metabolic screening as a strategy to further improve oral contraceptive safety. Recent developments in atherosclerosis research support the introduction of progestogens such as desogestrel that allow the estrogenic increase in high density lipoprotein levels to persist and that may cause less of an elevation in plasma insulin responses to glucose. The predicted benefit of these formulations in terms of arterial disease is difficult to demonstrate in an epidemiological setting because of the rarity of the disease in young women.

Blood Glucose↗
PubMed1998

Serotype distribution and prevalence of resistance to benzylpenicillin in three representative populations of Streptococcus pneumoniae isolates from the coast of Kenya.

As surveillance data from sub-Saharan Africa are few, three representative populations of Streptococcus pneumoniae isolates were examined in Kenya for serotype distribution and Etest minimum inhibitory concentrations (MICs) of benzylpenicillin: (1) 75 lung aspirate or blood culture isolates from 301 consecutive adult patients with pneumonia, (2) 112 invasive isolates from continuous pediatric inpatient surveillance over 4 years, and (3) 97 nasopharyngeal isolates from systematically selected sick children. The proportions with benzylpenicillin MICs of > or = 0.1 microgram/mL were 0.27, 0.29, and 0.47, respectively. Vaccine-related serotypes accounted for 96% of invasive isolates from children and 90% of those from human immunodeficiency virus (HIV)-seropositive adults. Serotype 1 accounted for 44% of pneumococci from HIV-seronegative patients but only 5% of those from HIV-seropositive patients (P = .0002). Of serotype 1 isolates, 98% were susceptible to benzylpenicillin, but serogroups 13, 14, 19, and 23 were strongly associated with an MIC of > or = 0.1 microgram/mL.

Adult↗
PubMed1998

Abdominal obesity, impaired nonesterified fatty acid suppression, and insulin-mediated glucose disposal are early metabolic abnormalities in families with premature myocardial infarction.

British Indian Asian men aged <40 years have a twofold to threefold increased risk of death from coronary heart disease (CHD) compared with British whites. Epidemiological studies have suggested an association between glucose intolerance and hyperinsulinemia with premature CHD in Indian Asians. We tested the association of insulin action with myocardial infarction (MI) by using the hyperinsulinemic-euglycemic clamp in 17 MI patients: 8 Punjabi Sikhs (PSMIs), 9 British whites (BWMIs), and 17 control subjects (9 PSCs and 8 BWCs). Metabolic factors associated with insulin resistance were investigated in 51 MI patients (24 PSMIs and 27 BWMIs) and 53 control subjects (28 PSCs and 25 BWCs). Familial aggregation of defective insulin action was examined by studying five pedigrees of Sikh survivors of MI. Sikh survivors of premature MI demonstrated impaired insulin-mediated glucose uptake (P<.001) by use of the clamp technique and nonesterified fatty acid (NEFA) suppression (P<.05) by using both clamp techniques and the oral glucose tolerance test, as compared with Sikh control subjects. White patients had impaired insulin-mediated glucose uptake but normal NEFA suppression. Metabolic factors usually associated with insulin resistance, including increased 2-hour post-oral glucose tolerance test triglycerides, smaller low density lipoprotein particle size, and increased plasminogen activator inhibitor-1, were present in white (all P<.05) but surprisingly absent in Sikh (all P>.05) MI patients compared with respective ethnic control subjects. Fasting glucose and total cholesterol levels did not differ between patients and control subjects. Abdominal obesity, impaired NEFA suppression after oral glucose, and fasting hyperinsulinemia were present in Sikh MI patients and their nondiabetic first-degree relatives compared with Sikh control subjects. PS survivors of premature MI demonstrated impaired insulin-mediated glucose disposal and NEFA suppression compared with ethnic control subjects. BWMI patients showed abnormalities of carbohydrate, but not of NEFA, metabolism compared with white control subjects. Defects of insulin action manifested as abdominal obesity, impaired NEFA suppression, and fasting hyperinsulinemia are present in Sikh MI patients and their asymptomatic, nondiabetic, first-degree relatives. We suggest that these defects may be early metabolic markers that predict risk of premature MI among PSs.

Abdomen↗
PubMed1997

Multicenter study of endocrine function and plasma lipids and lipoproteins in women using oral contraceptives containing desogestrel progestin. UK Desogen Study Group.

We assessed endocrine function and plasma lipid and lipoprotein concentrations in 112 women given a monophasic oral contraceptive containing 30 micrograms ethinyl estradiol and 150 micrograms desogestrel. These women were participating in a larger trial of cycle control and safety. Plasma concentrations of gonadotrophins, estradiol, and progesterone fell over the 18 months of this study, consistent with suppression of the hypothalamic-pituitary-ovarian (HPO) axis. There was no consistent effect on plasma prolactin concentrations. Concentrations of total triiodothyronine, thyroxine, and cortisol increased, tracking increases in their binding proteins. Within 6 months, plasma total cholesterol concentrations had increased by 12% (p < 0.001) with no effect on those of low density lipoproteins. Concentrations of triglycerides and high-density lipoprotein cholesterol increased by 79% and 14%, respectively (both p < 0.001). Monophasic ethinyl estradiol/desogestrel effectively suppressed the HPO axis. Other endocrine changes were typical of oral contraceptives containing ethinyl estradiol. The increase in triglyceride concentrations is not considered to increase cardiovascular risk, whereas the increase in high-density lipoproteins may be protective.

Cholesterol↗