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Biomedical subjects

R Holman

Publications and source records attributed to R Holman.

At least 19 recordsLinked to original sources
PubMed2001

Cost-effectiveness analysis of intensive blood-glucose control with metformin in overweight patients with type II diabetes (UKPDS No. 51).

AIMS/HYPOTHESIS: To estimate the economic efficiency of intensive blood-glucose control with metformin compared with conventional therapy primarily with diet in overweight patients with Type II (non-insulin-dependent) diabetes mellitus. METHODS: Cost-effectiveness analysis based on patient level data from a randomised clinical controlled trial involving 753 overweight (> 120% ideal body weight) patients with newly diagnosed Type II diabetes conducted in 15 hospital-based clinics in England, Scotland and Northern Ireland as part of the UK Prospective Diabetes Study. Subjects were allocated at random to an intensive blood-glucose control policy with metformin (n = 342) or a conventional policy primarily with diet (n = 411). The analysis was based on the cost of health care resources associated with metformin and conventional therapy and the estimated effectiveness in terms of life expectancy gained from within-trial effects. RESULTS: Intensive blood-glucose control with metformin produced a net saving of 258 Pounds per patient (1997 United Kingdom prices) over the trial period (median duration of 10.7 years) due to lower complication costs, and increased life expectancy by 0.4 years (costs and benefits discounted at 6%). CONCLUSIONS/INTERPRETATION: As metformin is both cost-saving in the United Kingdom and extends life expectancy when used as first line pharmacological therapy in overweight Type II diabetic patients, its use should be attractive to clinicians and health care managers alike.

Adult↗
PubMed2001

The UKPDS: implications for the dyslipidaemic patient.

The UK Prospective Diabetes Study (UKPDS) is the largest intervention trial to date of patients with type 2 diabetes, involving 5102 newly diagnosed diabetic patients. Results showed that 59% of patient deaths were from cardiovascular disease. While intensive treatment of glucose produced a significant 25% reduction in microvascular endpoints compared with diet only (p=0.0099), patients with type 2 diabetes usually have a lipid profile that is highly atherogenic. In the UKPDS, intensive treatment of hyperglycaemia and hypertension did not improve lipid levels. In patients without diabetes, lipid-lowering therapy has been shown to reduce the risk of cardiovascular events in both primary and secondary prevention trials. Currently, a number of large-scale trials of lipid-lowering therapy in patients with diabetes are ongoing. For example, the Lipids in Diabetes Study will determine whether lipid lowering with a statin or fibrate can substantially reduce cardiovascular morbidity and mortality in 5000 patients with type 2 diabetes. The Atorvastatin Study for the Prevention of coronary heart disease ENdpoints (ASPEN) is comparing double-blind treatment with atorvastatin and placebo in 2250 US diabetic patients without coronary heart disease, while a sister trial in the UK, the Collaborative AtoRvastatin Diabetes Study (CARDS), is enrolling 1820 diabetic patients. The results from these trials may provide information that which will help determine the future management of diabetic dyslipidaemia.

Clinical Trials as Topic↗
PubMed2001

Further diversity at HLA-A and -B loci identified in Afro-Caribbean potential bone marrow donors.

Two novel HLA-A and three novel HLA-B alleles were identified within a group of Afro-Caribbean individuals who were recruited as potential donors for the Anthony Nolan Bone Marrow Trust Register. HLA typing was performed on DNA extracted from peripheral blood mononuclear cells using sequence-specific oligonucleotide (SSO) probes for HLA-A and -B loci. Eight individuals analysed exhibited hybridisation patterns for which a type could not be assigned. DNA from these individuals was further typed by two methodologies: direct sequencing of PCR products and reference strand conformation analysis (RSCA). The direct sequencing results allowed the identification of new alleles but did not allow confirmation of the cis/trans orientation of the new sequence motifs identified. RSCA analysis confirmed the results obtained by SSO and direct sequencing and in addition confirmed the cis/trans orientation of the new sequences. One individual possesses a new A*30 allele--A*3008 and two individuals possess an identical new A*74 allele--A*7404. The three novel HLA-B alleles were identified in three individuals: B*0812, B*1554 and B*4503 respectively. For the remaining two samples, A*2612 was identified. At present Caucasoid individuals, and therefore Caucasoid phenotypes, are predominantly represented on the various different volunteer bone marrow donor registries. The examples presented here highlight the potential for identification of further polymorphisms within the HLA system as more individuals from the much-needed ethnic minorities are recruited onto bone marrow donor registers.

Alleles↗
PubMed2001

Identification of HLA-A*2306.

We describe a novel allele encoding HLA-A23: A*2306, discovered in an African-American individual, whose DNA was HLA typed as part of a quality control exercise. Direct sequencing typing identified A*2301 and A*6601 with an unexpected heterozygous peak at position 331. As position 331 is at the end of exon 2, near the priming site for the B3.6 anti-sense sequencing primer, the sequencing data is not optimal in this region and sequencing from the sense primer is relied on. In addition the new polymorphism was not at an expected polymorphic position and could easily have been missed, leading to the assignment of A*2301. However, data from reference strand mediated conformation analysis showed distinct new mobilities from those expected for A*2301 with two different fluorescent-labelled references, leading to the conclusion that the heterozygous peak seen at position 331 was a true variant of the A*2301 allele. A*2306 is most similar to A*2301 with 1 nucleotide difference at position 331 in exon 2 which was previously a conserved position. This mutation results in an amino acid substitution of glutamine for glutamate at residue 87.

Alleles↗
PubMed2001

An economic evaluation of atenolol vs. captopril in patients with Type 2 diabetes (UKPDS 54).

AIMS: To compare the net cost of a tight blood pressure control policy with an angiotensin converting enzyme inhibitor (captopril) or beta blocker (atenolol) in patients with Type 2 diabetes. DESIGN: A cost-effectiveness analysis based on outcomes and resources used in a randomized controlled trial and assumptions regarding the use of these therapies in a general practice setting. SETTING: Twenty United Kingdom Prospective Diabetes Study Hospital-based clinics in England, Scotland and Northern Ireland. SUBJECTS: Hypertensive patients (n = 758) with Type 2 diabetes (mean age 56 years, mean blood pressure 159/94 mmHg), 400 of whom were allocated to the angiotensin converting enzyme inhibitor captopril and 358 to the beta blocker atenolol. MAIN OUTCOME MEASURES: Life expectancy and mean cost per patient. RESULTS: There was no statistically significant difference in life expectancy between groups. The cost per patient over the trial period was 6485 UK pounds in the captopril group, compared with 5550 UK pounds in the atenolol group, an average cost difference of 935 UK pounds (95% confidence interval 188 UK pounds, 1682 UK pounds). This 14% reduction arose partly because of lower drug prices, and also because of significantly fewer and shorter hospitalizations in the atenolol group, and despite higher antidiabetic drug costs in the atenolol group. CONCLUSIONS: Treatment of hypertensive patients with Type 2 diabetes using atenolol or captopril was equally effective. However, total costs were significantly lower in the atenolol group. Diabet. Med. 18, 438-444 (2001)

Adrenergic beta-Antagonists↗
PubMed2000

Spinodal instabilities and the dark energy problem.

The accelerated expansion of the Universe measured by high redshift Type Ia supernova observations is explained using the nonequilibrium dynamics of naturally soft boson fields. Spinodal instabilities inevitably present in such systems yield a very attractive mechanism for arriving at the required equation of state at late times, while satisfying all the known constraints on models of quintessence.

Journal Article↗
PubMed2000

Cost effectiveness of an intensive blood glucose control policy in patients with type 2 diabetes: economic analysis alongside randomised controlled trial (UKPDS 41). United Kingdom Prospective Diabetes Study Group.

OBJECTIVE: To estimate the cost effectiveness of conventional versus intensive blood glucose control in patients with type 2 diabetes. DESIGN: Incremental cost effectiveness analysis alongside randomised controlled trial. SETTING: 23 UK hospital clinic based study centres. PARTICIPANTS: 3867 patients with newly diagnosed type 2 diabetes (mean age 53 years). INTERVENTIONS: Conventional (primarily diet) glucose control policy versus intensive control policy with a sulphonylurea or insulin. MAIN OUTCOME MEASURES: Incremental cost per event-free year gained within the trial period. RESULTS: Intensive glucose control increased trial treatment costs by pound 695 (95% confidence interval pound 555 to pound 836) per patient but reduced the cost of complications by pound 957 (pound 233 to pound 1681) compared with conventional management. If standard practice visit patterns were assumed rather than trial conditions, the incremental cost of intensive management was pound 478 (-pound 275 to pound 1232) per patient. The within trial event-free time gained in the intensive group was 0.60 (0.12 to 1.10) years and the lifetime gain 1.14 (0.69 to 1.61) years. The incremental cost per event-free year gained was pound 1166 (costs and effects discounted at 6% a year) and pound 563 (costs discounted at 6% a year and effects not discounted). CONCLUSIONS: Intensive blood glucose control in patients with type 2 diabetes significantly increased treatment costs but substantially reduced the cost of complications and increased the time free of complications.

Adult↗
PubMed2000

Life-expectancy projection by modelling and computer simulation (UKPDS 46).

A method is described for estimating the life-expectancy of cohorts of type 2 diabetic patients, based on computer simulation from a parametric model. The method can be used where non-parametric methods, such as the Kaplan-Meier estimate, fail due to lack of the data. The simulation algorithm combines observed and modelled information to estimate the life-expectancy implications of event rates observed within a study. The use of bootstrap methods to estimate confidence intervals is discussed. The methods are illustrated with results that have been previously published, without derivation, in a health economic analysis of tight blood pressure (BP) control in the UK Prospective Diabetes Study (UKPDS), and the application to other health economic analyses of UKPDS data is discussed.

Algorithms↗
PubMed1999

Genetic heterogeneity of autoimmune diabetes: age of presentation in adults is influenced by HLA DRB1 and DQB1 genotypes (UKPDS 43). UK Prospective Diabetes Study (UKPDS) Group.

AIMS/HYPOTHESIS: Juvenile-onset, insulin-dependent diabetes is associated with islet cell antibodies and with specific "high-risk" HLA-DRB1 and HLA-DQB1 genotypes. Patients with Type II (non-insulin-dependent) diabetes mellitus can have islet-related antibodies, but the genotypic associations at different ages of onset have not been evaluated. Our aim was to determine (i) the prevalence of DRB1 and DQB1 genotypes in patients at diagnosis of Type II diabetes at different ages from 25 to 65 years compared with the general population, and (ii) whether the presence of islet cell antibodies (ICA) or glutamic acid decarboxylase antibodies (GADA) or both by age is associated with different DRB1 and DQB1 genotypes. METHODS: The antibodies to islet cells and those to glutamic acid decarboxylase were measured in 1712 white Caucasian diabetic subjects at diagnosis of diabetes and they were genotyped for HLA DRB1*03 and DRB1*04 and the high-risk DRB1*04-DQB1* 0302 haplotype. To assess over-representation of high-risk alleles for Type I (insulin-dependent) diabetes mellitus, the prevalence of high-risk alleles in diabetic patients was expressed relative to the prevalence of low-risk alleles, non-DR3/non-DR4, that provided a reference denominator in both the diabetic patients and in 200 non-diabetic control subjects. The prevalence of ICA or GADA or both in patients with different HLA genotypes was assessed in those diagnosed in four age groups, 25-34 years, 35-44 years, 45-54 years and 55-65 years. RESULTS: In Type II diabetic patients presenting at ages 25-34, 35-44 and 45-54 years, there was an increased prevalence of DR3/DR4 compared with the general population with approximately 6.5-fold, 2.9-fold, 2.1-fold over-representation, respectively (p < 0.0001, < 0.01, < 0.05) but this was not found in those aged 55-65 years old. In the group aged 25-34 years, 32 % of patients with ICA or GADA or both had DRB1*03/DRB1*04-DQB1*0302 compared with 10% in those aged 55-65 years and expected 3% prevalence. Conversely, only 14% of those aged 25-34 years with antibodies had non-DR3/non-DR4, compared with 35 % in those aged 55-65 years. There was thus pronounced age heterogeneity in DRB1 and DQB1 predisposition to Type II diabetes. The antibodies displaced DRB1 or DQB1 genotypes in the multivariate model for requiring insulin therapy by 6 years of follow-up. CONCLUSION/HYPOTHESIS: The age of presentation of Type I diabetes in adulthood was in part dependent on the DRB1/DQB1 genotype. Islet cell antibodies and glutamic acid decarboxylase antibodies were strongly associated with DRB1*03/DRB1*04-DQB1*0302 in early adulthood but showed little relation with specific HLA genotypes after the age of 55 years.

Adult↗
PubMed1999

HLA-A, -B, -C polymorphism in a UK Ashkenazi Jewish potential bone marrow donor population.

To further our knowledge of HLA polymorphism in different ethnic populations and to increase the number of full HLA class I typed potential bone marrow donors on the Anthony Nolan Bone Marrow Trust register, HLA-A, -B and -C polymorphism was characterised in 412 Ashkenazi Jewish potential donors. Serological typings and limited molecular analysis was performed for HLA-A and -B, and molecular typings were performed for HLA-C. Gene and haplotype frequencies were calculated using the maximum likelihood method and compared with UK Caucasoid and other Jewish populations. While the specificities identified were in general overlapping with the UK Caucasoid data, a difference in the frequencies of individual specificities was observed. For example, HLA-B62, a common serotype found in the UK Caucasoid population, is almost absent in the Ashkenazim. HLA-A, -C, -B haplotype frequencies also differ between the two populations with A26-Cw*1203-B38 and A24-Cw*04-B35 significant in the Ashkenazim, whilst A1-Cw*07-B8, a common Caucasoid haplotype, was found to be less frequent. Overall the results for the UK Ashkenazi population were most similar to previous reports on Polish/Russian Jews.

Adolescent↗
PubMed1997

Characterization of apical and basolateral plasma membrane domains derived from cultured rat cholangiocytes.

Cholangiocytes, the epithelial cells that line intrahepatic bile ducts, are composed of plasma membranes with discrete apical (lumenal) and basolateral domains that contain different channels, transporters, and receptors. In recent work, we developed a long-term, primary culture system of normal rat cholangiocytes (NRC). Our aims here were to prepare and characterize apical and basolateral plasma membrane vesicles from NRC. Using serial isopycnic centrifugation on sucrose gradients, we generated separate apical and basolateral plasma membrane vesicles. We characterized these vesicles by transmission electron microscopy, specific marker enzyme assays, and immunoblotting; we also determined the percentage of sealed vesicles and their intravesicular volume and sidedness using biochemical approaches. Our results showed that vesicles derived from the apical and basolateral plasma membrane domains of NRC were highly purified, predominately sealed, right-side-out vesicles that differed in size and lipid and protein composition. This experimental model represents a novel tool that will be useful for additional functional studies on the channels, transporters, and receptors differentially distributed in the plasma membrane of biliary epithelia.

Animals↗
PubMed1997

UKPDS 25: autoantibodies to islet-cell cytoplasm and glutamic acid decarboxylase for prediction of insulin requirement in type 2 diabetes. UK Prospective Diabetes Study Group.

BACKGROUND: Autoantibodies to islet-cell cytoplasm (ICA) and glutamic acid decarboxylase (GADA) can occur in apparently typical, non-insulin dependent diabetes mellitus (type 2). We investigated whether the presence of either or both antibodies characterises a subtype of diabetes and provides better prediction of requirement for insulin therapy by 6 years' follow-up than clinical variables. METHODS: We measured ICA and GADA at diagnosis of diabetes in a representative population of 3672 white patients with type 2 diabetes, aged between 25 and 65 years. The phenotype was assessed by age of onset, body-mass index, percentage haemoglobin A1c (HbA1c), and islet beta-cell function. We investigated the need for insulin therapy among 1538 patients not assigned insulin and followed up for 6 years from diagnosis. FINDINGS: The proportion of patients with ICA and GADA decreased with increasing age at diagnosis (from 33 [21%] of 157 patients aged 25-34 [corrected] to 66 [4%] of 1769 aged 55-65 for ICA; from 53 [34%] to 122 [7%] for GADA). Among patients younger than 35 at diagnosis, those with ICA or GADA had lower body-mass index than those without (mean 24.9 [SD 6.0] vs 31.7 [7.3] kg/m2; p < 0.0001 and had higher percentage of HbA1c (9.7 vs 8.7%, p < 0.05). 94% of patients with ICA and 84% of those with GADA required insulin therapy by 6 years, compared with 14% of those without the antibodies (p < 0.0001). Among patients older than 55 at diagnosis, the difference between those with and without antibodies in body-mass index was smaller (27.2 [5.4] vs 28.6 [4.8] kg/m2, p < 0.001); 44% of those with ICA, 34% of those with GADA, and 5% with neither antibody required insulin therapy by 6 years (p < 0.0001). Among patients older than 45 years, body-mass index and HbA1c provided little predictive information for insulin requirement, whereas the positive predictive values of GADA (> or = 60 U/L) alone, or both GADA (> or = 20 U/L) and ICA (> 5 U/L), for insulin therapy were 52% and 68%. INTERPRETATION: Among young adults with type 2 diabetes, the phenotype of those with ICA or GADA antibodies was similar to that of classic juvenile-onset insulin-dependent diabetes, and either phenotype or antibodies predicted insulin requirement. In older adults, the phenotype was closer to that of patients without antibodies and only the presence of antibodies predicted an increased likelihood of insulin requirement.

Adult↗