A Type 1 Diabetes Genetic Risk Score Predicts Progression of Islet Autoimmunity and Development of Type 1 Diabetes in Individuals at Risk

OBJECTIVE

We tested the ability of a type 1 diabetes (T1D) genetic risk score (GRS) to predict progression of islet autoimmunity and T1D in at-risk individuals.

RESEARCH DESIGN AND METHODS

We studied the 1,244 TrialNet Pathway to Prevention study participants (T1D patients' relatives without diabetes and with one or more positive autoantibodies) who were genotyped with Illumina ImmunoChip (median [range] age at initial autoantibody determination 11.1 years [1.2-51.8], 48% male, 80.5% non-Hispanic white, median follow-up 5.4 years). Of 291 participants with a single positive autoantibody at screening, 157 converted to multiple autoantibody positivity and 55 developed diabetes. Of 953 participants with multiple positive autoantibodies at screening, 419 developed diabetes. We calculated the T1D GRS from 30 T1D-associated single nucleotide polymorphisms. We used multivariable Cox regression models, time-dependent receiver operating characteristic curves, and area under the curve (AUC) measures to evaluate prognostic utility of T1D GRS, age, sex, Diabetes Prevention Trial-Type 1 (DPT-1) Risk Score, positive autoantibody number or type, HLA DR3/DR4-DQ8 status, and race/ethnicity. We used recursive partitioning analyses to identify cut points in continuous variables.

RESULTS

Higher T1D GRS significantly increased the rate of progression to T1D adjusting for DPT-1 Risk Score, age, number of positive autoantibodies, sex, and ethnicity (hazard ratio [HR] 1.29 for a 0.05 increase, 95% CI 1.06-1.6; P = 0.011). Progression to T1D was best predicted by a combined model with GRS, number of positive autoantibodies, DPT-1 Risk Score, and age (7-year time-integrated AUC = 0.79, 5-year AUC = 0.73). Higher GRS was significantly associated with increased progression rate from single to multiple positive autoantibodies after adjusting for age, autoantibody type, ethnicity, and sex (HR 2.27 for GRS >0.295, 95% CI 1.47-3.51; P = 0.0002).

CONCLUSIONS

The T1D GRS independently predicts progression to T1D and improves prediction along T1D stages in autoantibody-positive relatives.

Expanding the Clinical Spectrum Associated With GLIS3 Mutations

CONTEXT

GLIS3 (GLI-similar 3) is a member of the GLI-similar zinc finger protein family encoding for a nuclear protein with 5 C2H2-type zinc finger domains. The protein is expressed early in embryogenesis and plays a critical role as both a repressor and activator of transcription. Human GLIS3 mutations are extremely rare.

OBJECTIVE

The purpose of this article was determine the phenotypic presentation of 12 patients with a variety of GLIS3 mutations.

METHODS

GLIS3 gene mutations were sought by PCR amplification and sequence analysis of exons 1 to 11. Clinical information was provided by the referring clinicians and subsequently using a questionnaire circulated to gain further information.

RESULTS

We report the first case of a patient with a compound heterozygous mutation in GLIS3 who did not present with congenital hypothyroidism. All patients presented with neonatal diabetes with a range of insulin sensitivities. Thyroid disease varied among patients. Hepatic and renal disease was common with liver dysfunction ranging from hepatitis to cirrhosis; cystic dysplasia was the most common renal manifestation. We describe new presenting features in patients with GLIS3 mutations, including craniosynostosis, hiatus hernia, atrial septal defect, splenic cyst, and choanal atresia and confirm further cases with sensorineural deafness and exocrine pancreatic insufficiency.

CONCLUSION

We report new findings within the GLIS3 phenotype, further extending the spectrum of abnormalities associated with GLIS3 mutations and providing novel insights into the role of GLIS3 in human physiological development. All but 2 of the patients within our cohort are still alive, and we describe the first patient to live to adulthood with a GLIS3 mutation, suggesting that even patients with a severe GLIS3 phenotype may have a longer life expectancy than originally described.

Type 2 diabetes and cardiovascular disease in polycystic ovary syndrome: what are the risks and can they be reduced?

Polycystic ovary syndrome (PCOS) is a risk factor for Type 2 diabetes mellitus (T2DM) and cardiovascular disease (CVD), but these risks are poorly defined. This study aimed to evaluate the evidence for these risks and whether screening and risk reduction are feasible. Medline reviews and data quality analysis were used using standard tools. Results showed that (i) polycystic ovary syndrome is a risk factor forT2DM but the magnitude of risk is uncertain, (ii) fasting plasma glucose is an inadequate screening test forT2DM in this population and the oral glucose tolerance test is superior, (iii) the identification of women with PCOS for diabetes screening is constrained by current diagnostic criteria for PCOS; however, women with oligomenorrhoea and those with diagnosed PCOS and obesity or a family history of T2DM are at highest risk, (iv) risk factors for T2DM are improved by weight loss interventions and by metformin. However, no studies have determined whether T2DM incidence is reduced, (v) polycystic ovary syndrome is associated with cardiovascular disease (CVD) risk factors but data on CVD incidence are weak, (vi) risk factors for CVD are improved by the same interventions and statins and (vi) no studies have evaluated whether CVD incidence is reduced. While PCOS has important metabolic associations, and short-term interventions reduce risk factors for T2DM and CVD, data on prevalence and incidence of T2DM and particularly CVD are poor. There is a need for a clear definition of PCOS, for diabetes screening protocols and for long-term studies to determine whether risks can be reduced.

The effect of the availability of inhaled insulin on glycaemic control in patients with Type 2 diabetes failing on oral therapy: the evaluation of Exubera as a therapeutic option on insulin initiation and improvement in glycaemic control in clinical practice (EXPERIENCE) trial

AIM

To examine the impact of inhaled human insulin (Exubera, EXU) on patient or physician willingness to adopt insulin after oral glucose-lowering agent failure.

METHODS

During a randomized controlled trial in primary, secondary and tertiary care in Europe and North America, 739 patients using >or= 2 oral glucose-lowering agents with glycated haemoglobin (HbA(1c)) >or= 8.0% were assigned to two treatment groups: Group 1 (standard care with the option of EXU) or Group 2 (standard care only). Standard care included adjusting oral therapy (optimizing current regimen or adding/omitting agents) and/or initiating subcutaneous (s.c.) insulin. The primary endpoint was difference in HbA(1c) between randomized groups at 26 weeks. Secondary outcomes included differences in the rate of uptake of insulin therapy, proportion achieving satisfactory glycaemic control, treatment satisfaction and safety outcomes.

RESULTS

At baseline, insulin was initiated by more [odds ratio 6.0; 95% confidence interval (CI) 4.2 to 8.8; P < 0.0001] patients in Group 1 (86.2%; 76.7% EXU plus 9.5% s.c.) than Group 2 (50.7%; s.c. insulin only). At 26 weeks, mean (sd) changes in HbA(1c) from baseline were -2.0% (1.2%) and -1.7% (1.3%) in Groups 1 and 2, respectively, a difference of -0.2% (95% CI: -0.1% to -0.4%; P = 0.004). In Group 1, 45% of patients achieved an HbA(1c)<or= 7.0% by 26 weeks compared with 39% in Group 2 (P = 0.02).

CONCLUSION

The availability of EXU may increase initiation of insulin, thereby contributing to improved overall glycaemic control in patients with Type 2 diabetes inadequately controlled on two or more oral glucose-lowering agents.

Prevalence and clinical implications of the inter-arm blood pressure difference: a systematic review

A blood pressure (BP) difference between arms was first reported over 100 years ago. Knowledge of its prevalence and relevance to the accurate measurement of BP remains poor. Current hypertension guidelines do not emphasise it. The objectives of this study were to establish the best estimate of prevalence of the inter-arm difference (IAD) in the population, to consider its implications for accurate BP measurement and treatment, and to discuss its aetiology and potential as a risk marker for cardiovascular disease. Systematic literature review was carried out. The data sources were Medline EMBASE and CINAHL databases, and Index of Theses. Studies reporting prevalence rates of IAD were retrieved and considered for inclusion against explicit methodological criteria. Point prevalence rates were extracted and weighted mean prevalence rates calculated. The main outcome measures were weighted mean prevalences of systolic IAD > or =10 and > or =20 mm Hg and of diastolic IAD > or =10 mm Hg. Thirty-one studies were identified. Most had methodological weaknesses; only four met the inclusion criteria. Pooled prevalences of the IAD from these four studies were 19.6% systolic > or =10 mm Hg (95% CI 18.0-21.3%), 4.2% systolic > or =20 mm Hg (95% CI 3.4-5.1%) and 8.1% diastolic > or =10 mm Hg (95%CI 6.9-9.2%). In conclusion, an IAD is present in a substantial number of patients and should be looked for whenever diagnosis and treatment depend on accurate measurements of BP. The importance of an IAD should be better emphasised in current hypertension management guidelines. There is evidence associating an IAD with peripheral vascular disease, raising the possibility that its presence may predict cardiovascular events.

Polymorphisms of chemokine and chemokine receptor genes in Type 1 diabetes mellitus and its complications

Cytokines and chemokines have been implicated in the pathogenesis of Type 1 diabetes mellitus (T1DM) and its microvascular complications. Recently, genetic variants of monocyte chemotactic protein-1 (MCP-1), CC-chemokine receptor 2 (CCR2), CC-chemokine receptor 5 (CCR5) genes have been identified. The aim was to investigate whether genetic variants of the MCP-1 G(-2518)A, CCR2B 64I, CCR5 G(59029)A, and CCR5 Delta32 are associated with T1DM and its microvascular complications. Two hundred and sixty patients with T1DM with and without diabetic microvascular complications, and 104 normal controls were recruited for this study. Genotypes of the MCP-1 G(-2518)A, CCR2B 64I, CCR5 G(59029)A, and CCR5 delta32 were performed by polymerase chain reaction followed by digestion with appropriate restriction endonucleases. Frequencies of the MCP-1 A(-2518) allele (74.6% vs. 63.5%, p < 0.003) and A/A genotype (54.5% vs. 34.6%, p < 0.001, Pc = 0.002) were significantly higher in patients with T1DM compared with normal controls. CCR5 G(59029) was slightly increased in the patients with microvascular complications compared with the uncomplicated (21.4% vs. 10%, p < 0.03, Pc = ns). The frequency of haplotype G/G/W was slightly increased in the patients with diabetic complications compared to the uncomplicated (39.6% vs. 28.8%, p < 0.02, Pc = ns). These results suggest that polymorphisms of the MCP-1, CCR2 and CCR5 genes may be associated with T1DM and its complications.

Functional differences between the susceptibility Z-2/C-106 and protective Z+2/T-106 promoter region polymorphisms of the aldose reductase gene may account for the association with diabetic microvascular complications

Studies have shown that polymorphisms located at positions -106 and approximately -2100 base pairs (5'ALR2) in the regulatory region of the aldose reductase gene are associated with susceptibility to microvascular complications in patients with diabetes. The aim was to investigate the functional roles of these susceptibility alleles using an in vitro gene reporter assay. Susceptibility, neutral and protective 5'ALR2/-106 alleles were transfected into HepG2 cells and exposed to excess D-glucose (D-glucose at final concentrations 14 or 28 mmol/l). Transcriptional activities were determined using a dual luciferase reporter gene assay. The "susceptibility alleles" Z-2 with C-106 had the highest transcriptional activity when compared with the "protective" combination of Z+2 with C-106 alleles (58.7+/-9.9 vs. 10.1+/-0.7; P<0.0001). Those constructs with either the Z or Z-2 in combination with the C-106 allele had significantly higher transcriptional activities when compared to those with the T-106 allele (Z/C-106, 37.4+/-5.4 vs. Z/T-106 7.7+/-1.6, P<0.003; Z-2/C-106, 58.7+/-9.9 vs. Z-2/T-106 10.9+/-0.6, P<0.0001). These results demonstrate that the Z-2/C-106 haplotype is associated with elevated transcriptional activity of the aldose reductase gene. This in turn may explain the role of these polymorphisms in the susceptibility to diabetic microvascular complications.

Community care in practice: social work in primary health care

This paper examines the establishment of social work within primary health care settings in Great Britain, following the passage of the National Health Service and Community Care Act in 1990. Although the improvement of relationships between social workers and primary health care teams has been promoted for a number of years, the advent of formal policies for community care has made this a priority for both social services and health. This paper presents interim findings from the evaluation of three pilot projects in Nottinghamshire, Great Britain. These findings are analysed from three linked perspectives. The first is the extent to which structures and organisations have worked effectively together to promote the location of social workers within health care settings. The second is the impact of professional and cultural factors on the work of the social worker in these settings. The third is the effect of interpersonal relationships on the success of the project. The paper will conclude that there is significant learning from each of these perspectives which can be applied to the future location of social workers to primary health care.

Polymorphisms of the aldose reductase gene and susceptibility to retinopathy in type 1 diabetes mellitus

PURPOSE

Aldose reductase (ALR2) is the first and rate-limiting enzyme of the polyol pathway and is involved in the pathogenesis of diabetic retinopathy. Polymorphisms of the ALR2 gene are associated with susceptibility to diabetic retinopathy in Chinese and Japanese patients with type 2 diabetes. There are no reports investigating these polymorphisms in white patients with type 1 diabetes from either Western Europe or North America. A CA dinucleotide repeat polymorphism (5'ALR2; located at -2100 bp) as well as a novel C(106)T polymorphism was investigated in 229 white patients with type 1 diabetes, with or without retinopathy.

METHODS

The DNA was typed for these polymorphisms using conventional polymerase chain reaction techniques.

RESULTS

There was a highly significant increase in the frequency of the Z-2 5'ALR2 allele and Z-2/X (where X is not Z+2) genotype in patients with diabetic retinopathy (n = 159) compared with those without who had diabetes of 20 years' duration (uncomplicated, n = 70; chi(2) = 17.0, P < 0.0001). There was a similar decrease in the Z+2/Y genotype (where Y is not Z-2; chi(2) = 30.1, P < 0.000,001) in the patients with retinopathy compared with the uncomplicated diabetes group. The C/Z-2 C(-106)T/5' ALR2 haplotype was found in 33.3% of the patients with retinopathy and 8.7% of the patients with uncomplicated diabetes.

CONCLUSIONS

These results confirm previous studies in other populations and in type 2 diabetes showing that polymorphisms in the promoter region of the ALR2 gene are associated with susceptibility to diabetic retinopathy.

A CA repeat polymorphism of the IFN-gamma gene is associated with susceptibility to type 1 diabetes

Recent studies have shown that loci outside the HLA region are involved in determining susceptibility to type 1 diabetes. Polymorphisms in the coding and noncoding regions of the genes encoding cytokines may be involved in modulating the immune response to self and nonself antigens. There is increasing evidence that an imbalance and disruption of the Thl and Th2 T cell subsets play a key role in the development of experimental and clinical type 1 diabetes. The aim of this study was to investigate the frequency of a CA dinucleotide repeat polymorphism in the interferon-gamma (IFN-gamma) gene (IFNG) and a C(-590)T polymorphism of the interleukin-4 (IL-4) gene in 236 Caucasoid patients with type 1 diabetes. There was a highly significant increase in the 3/3 IFNG genotype in the patients compared with normal healthy controls (34.3% vs. 13.5%, p<0.0001) as well as a significant increase in allele 3 of the IFNG locus in the patients compared with controls (51.9% vs. 31.7%, p<0.00001). In contrast, no significant differences were found in the frequency of the C(-590)T IL-4 polymorphism between patients and controls. These results suggest that polymorphisms of the IFNG gene may modify the function of this proinflammatory mediator and the response to pancreatic islet beta cells.

Missense mutations in the insulin promoter factor-1 gene predispose to type 2 diabetes

The transcription factor insulin promoter factor-1 (IPF-1) plays a central role in both the development of the pancreas and the regulation of insulin gene expression in the mature pancreatic beta cell. A dominant-negative frameshift mutation in the IPF-l gene was identified in a single family and shown to cause pancreatic agenesis when homozygous and maturity-onset diabetes of the young (MODY) when heterozygous. We studied the role of IPF-1 in Caucasian diabetic and nondiabetic subjects from the United Kingdom. Three novel IPF-1 missense mutations (C18R, D76N, and R197H) were identified in patients with type 2 diabetes. Functional analyses of these mutations demonstrated decreased binding activity to the human insulin gene promoter and reduced activation of the insulin gene in response to hyperglycemia in the human beta-cell line Nes2y. These mutations are present in 1% of the population and predisposed the subject to type 2 diabetes with a relative risk of 3.0. They were not highly penetrant MODY mutations, as there were nondiabetic mutation carriers 25-53 years of age. We conclude that mutations in the IPF-1 gene may predispose to type 2 diabetes and are a rare cause of MODY and pancreatic agenesis, with the phenotype depending upon the severity of the mutation.

Susceptibility to diabetic neuropathy in patients with insulin dependent diabetes mellitus is associated with a polymorphism at the 5' end of the aldose reductase gene

OBJECTIVES

There is evidence that the polyol pathway is involved in the pathogenesis of diabetic neuropathy. Aldose reductase (ALR2) is the first and rate limiting enzyme of this pathway and recent studies have suggested that polymorphisms in and around the gene are associated with the development of diabetic microvascular disease. The aim was to examine the role of ALR2 in the susceptibility to diabetic neuropathy in patients with insulin dependent diabetes mellitus (IDDM).

METHODS

One hundred and fifty nine British white patients with IDDM and 102 normal healthy controls were studied using the polymerase chain reaction to test for a highly polymorphic microsatellite marker 2.1 kilobase (kb) upstream of the initiation site of the ALR2 gene.

RESULTS

Seven alleles were detected (Z-6, Z-4, Z-2, Z, Z+2, Z+4, and Z+6). There was a highly significant decrease in the frequency of the Z+2 allele in those patients with overt neuropathy compared with those with no neuropathy after 20 years duration of diabetes (14.1% v 38.2%, chi2 =17.3, p<0.00001). A similar difference was also found between the neuropathy group and those patients who have had diabetes for < five years with no overt neuropathy (14.1% v 30.2%, chi2=9.0, p<0.0025). The neuropathy group also had a significant decrease in the frequency of the Z/Z+2 genotype compared with those patients who have no neuropathy after 20 years duration of diabetes (14.0% v 44.7%, chi2=13.0, p<0.0005).

CONCLUSION

These results suggest that the aldose reductase gene is intimately involved in the pathogenesis of diabetic neuropathy.

Polymorphism in the 5'-end of the aldose reductase gene is strongly associated with the development of diabetic nephropathy in type I diabetes

Recent studies suggest that the gene encoding aldose reductase (ALR2), the enzyme that converts glucose to sorbitol, may confer susceptibility to microvascular disease. DNA from 275 British Caucasian patients with type I diabetes and 102 normal healthy control patients were typed for a (CA)n dinucleotide repeat polymorphic marker in the 5'-region of the ALR2 gene using polymorase chain reaction (PCR). A highly significant decrease in the frequency of the Z+2 allele was found in patients with nephropathy (nephropathy group) compared with those with no complications after a 20-year duration of diabetes (uncomplicated group) (12.7 vs. 38.2%, respectively, chi2 = 18.6, P < 0.00001); this was accompanied by an increase in the Z-2 allele in the nephropathy group (32.0 vs. 12.7% in the uncomplicated group). The nephropathy group also had a significant decrease in the Z/Z+2 genotype compared with the uncomplicated patients (10.7 vs. 44.7%, chi2 = 16.0, P < 0.0001) and an increased frequency of the Z/Z-2 genotype. There was no significant association with diabetic retinopathy. These results demonstrate that the ALR2 gene may play a role in susceptibility to diabetic nephropathy; individuals with the Z+2 allele are more than seven times less likely to develop diabetic renal disease than those without this marker. This marker may prove valuable in screening for patients with diabetic nephropathy at diagnosis of diabetes.

Continuous monitoring of salivary flow rate and pH at the surface of the dentition following consumption of acidic beverages

Use of a splint-mounted flexible pH electrode has allowed reliable continuous monitoring of pH at the surface of the dentition whilst still enabling subjects to drink normally. pH was monitored at the palatal upper left central incisor and upper right first permanent molar sites after drinking 1% (w/v) citric acid. A maximal decrease in pH to values of 2-3 was observed after 1 min followed by a slower recovery which was above pH 5.5 within 2 min at the former site and in 4-5 min at the latter site. A sharp rise in parotid saliva flow rate was seen at 1 min after drinking the same concentration of citric acid by glass, straw or feeder cup, which returned to resting levels within 6 min although the fall-off of flow rate was slower with the feeder cup. Thus, after dietary acid intake the pH at the surface of the dentition is below the critical pH for enamel dissolution for shorter periods than previously suggested, which is probably a reflection of salivary neutralisation and washing.

In vitro techniques for erosive lesion formation and examination in dental enamel

An in vitro experimental model has been developed for erosive lesion formation in dental enamel which can mimic in vivo conditions at the tooth surface. The features of this model provide a very reproducible method of producing erosive lesions in several teeth under identical conditions which can be varied to allow examination of a number of different parameters. A replica impression technique has also been developed for subsequent non-destructive microscopic examination of the lesions and comparison with in vivo lesions.

The distribution and severity of tooth wear and the relationship between erosion and dietary constituents in a group of children

There is very little published information on the severity of tooth wear in children. The current investigation involved clinical examination of 101 children and an assessment of their dietary habits. Evidence of tooth wear was found in over 80% of maxillary incisor teeth, and 30% of primary molar teeth had some dentine exposed. There were 21 children who were regarded as having 'mild' erosion, 45 'moderate' erosion and 35 'severe' erosion. There were highly statistically significant differences between the three groups in relation to drinking habits; the mean number of carbonated drinks consumed per week by children in the 'mild', 'moderate' and 'severe' erosion groups was 3.9, 5.8 and 13.9 respectively, of fruit drinks 10.3, 16.4 and 18.3, and of all fruit-based drinks 17.9, 27.1 and 39.0. There were also highly significant differences in those having a fruit-based drink at bed-time; 14% in the 'mild' erosion group, 32% in the 'moderate' and 60% in the 'severe' group. Although fresh fruit and yoghurt consumption followed the same trend, this did not reveal statistically significant differences. It is important to identify children who exhibit clinical evidence of erosion so that advice can be given about consumption of acidic dietary constituents.

Dental erosion in four-year-old children from differing socioeconomic backgrounds

Although there is very little epidemiological evidence on the prevalence and severity of erosion in children and adults, there have been recent case reports suggesting that the problem of erosion is increasing. This study describes the use of a simple reproducible erosion index. A total of 178 four-year-old children were assessed; almost half of these children showed signs of erosion. The most common site affected was the palatal surface of the upper incisors with 17 percent of the children examined showing visible dentine for greater than one third of the tooth surface. When considering the influence of socioeconomic group on the prevalence of erosion, four out of five children examined in the low socioeconomic group showed low levels of erosion, while a much greater prevalence was observed in the higher socioeconomic groups.

Analysis of the peripheral T-cell receptor V beta repertoire in newly diagnosed patients with type I diabetes

Type I diabetes is an autoimmune disease characterised by a marked activation of peripheral T cells around the time of clinical diagnosis. Studies of T-cell antigen receptor V beta (TCRBV) gene usage in type I diabetes have been conflicting. Using a semi-quantitative polymerase chain reaction technique and flow cytometry we have investigated the TCRBV gene usage of 13 newly diagnosed patients with type I diabetes and 11 normal healthy controls. No preferential TCRBV gene usage was found between patients and controls even after matching for HLA-DR3 and/or -DR4. In addition, no significant differences in TCRBV gene usage were found between sequential samples taken over a period of up to 7 months following diagnosis. These results suggest that the TCR repertoire of these patients is heterogeneous and it is unlikely that a single 'pathogenic' T-cell clone is dominant at the clinical onset of the disease.

Engineered secreted T-cell receptor alpha beta heterodimers

We have produced a soluble form of a mouse alpha beta T-cell antigen receptor (TCR) by shuffling its variable (V) and constant (C) domains to the C region of an immunoglobulin kappa light chain. These chimeric molecules composed of V alpha C alpha C kappa and V beta C beta C kappa chains were efficiently secreted (up to 1 micrograms/ml) by transfected myeloma cells as noncovalent heterodimers of about 95-kDa molecular mass. In the absence of direct binding measurement, we have refined the epitopic analysis of the soluble V alpha C alpha C kappa-V beta C beta C kappa dimers and shown that they react with an anti-clonotypic antibody and two antibodies directed to the C domain of the TCR alpha and beta chains. Conversely, we have raised three distinct monoclonal antibodies against the soluble TCR heterodimers and shown that they recognize surface-expressed TCRs. Two of these antibodies were found to react specifically with the products of the V alpha 2 (V delta 8) and V beta 2 gene segments, respectively. When considered together, these data suggest that these soluble TCR molecules are folded in a conformation indistinguishable from that which they assume at the cell surface.

Susceptibility to type I diabetes in women is associated with the CD3 epsilon locus on chromosome 11

Type I diabetes is associated with the DQ loci of the MHC and to a lesser extent with the T cell antigen receptor (TcR) beta chain genes. The non-obese diabetic (NOD) mouse is an animal model of human diabetes, in which up to 90% of female mice develop overt insulin-dependent diabetes. Genetic studies in the NOD mouse suggest that there are at least three diabetogenic genes; one that maps to the MHC, another that may map to the mouse Thy-I locus, and a third that has still to be identified. We have investigated loci in the vicinity of the human Thy-I locus on chromosome 11q23 and report here the results of restriction fragment length polymorphism (RFLP) analysis of the CD3 epsilon locus of 168 Caucasoid patients with type I diabetes. While no association was found between this locus and type I diabetes, a significant difference in the frequency of the CD3 epsilon 8-kb allele was found between male and female patients (0.268 versus 0.430; P less than 0.0025, Pc = 0.02) and between female patients and healthy female controls (0.430 versus 0.267; P less than 0.015). These results suggest that a gene residing on chromosome 11q23 may confer susceptibility to type I diabetes in women.

Complement C4 and heat shock protein 70 (HSP70) genotypes and type I diabetes mellitus

Type I diabetes is strongly associated with the major histocompatibility complex (MHC) class II region (DR and DQ loci), and to a lesser extent the class III region (complement C4 loci). Restriction fragment length polymorphism analysis was employed to investigate the C4 and heat shock protein 70 (HSP70) loci of 176 patients with type I diabetes and 92 healthy controls. In the patient population there was an excess of deletions of the C4A locus (48.5% vs 22.1%, P less than 0.0005). The HSP70 probe in conjunction with the restriction endonuclease Pst I detects two alleles of 9 or 8.5 kilobases (kb). The 8.5 kb allele was significantly increased in the patient group compared to healthy controls (0.569 vs 0.353, respectively, P less than 0.0005). Furthermore, a C4A deletion nearly always occurred with the 8.5 kb HSP70 allele, suggesting that it may be a marker of the HLA-A1,B8,C4A deletion, DR3 extended haplotype.

Characterization of islet cell antibody in insulin dependent diabetes: evidence for IgG1 subclass restriction and polyclonality

Using an indirect immunofluorescence technique we have investigated the titre, immunoglobulin class, complement-fixing ability, light chain type and IgG subclass of islet cell antibodies (ICA) in the sera of 21 recently diagnosed insulin-dependent diabetics and four non-diabetics before they developed diabetes. In the recently diagnosed patients titres of ICA ranged from 1/10 to 1/640. ICA belonged to the IgG class in all cases and fixed complement in 14 (67%). In all patients tested both kappa and lambda light chains were found, indicating that the antibody is polyclonal. IgG subclasses of ICA were investigated using specific murine monoclonal antibodies. All patients had ICA of the IgG1 subclass and in 16 (76%) this was the only subclass detected. In the remainder, one or more of the other IgG subclasses were found in association with IgG1. In the four pre-diabetic patients ICA fixed complement, was polyclonal and in all cases was of the IgG1 subclass. These characteristics of ICA, therefore, precede the onset of diabetes. The titre of ICA in the pre-diabetics tended to be greater (range 1/320 to (1/1280) than in the recently diagnosed diabetics. These results demonstrate restriction of ICA to the IgG1 subclass.

A study of the forces exerted by an oarsman and the effect on boat speed

A model of the motion of a single-scull rowing hull has been developed and verified against rowing performance data. The model was then used to explore the effect of changes in the cyclic rowing force on the boat speed. The calculations have shown that the shape of the rowing force curve and the proportion of recovery time in the total stroke can have an important effect on the boat speed. It has also been shown that a study of the fluid mechanics of the oar blade would be advantageous in determining whether a reduction in the power wasted can be obtained by changing the ratio of rowing force to normal force.