Large-scale studies of the association between variation at the TNF/LTA locus and susceptibility to type 2 diabetes

AIMS/HYPOTHESIS

The proinflammatory cytokine TNF-alpha has been implicated in the pathogenesis of insulin resistance and type 2 diabetes, and variation in the gene encoding TNF-alpha (TNF) has shown inconsistent associations with susceptibility to both conditions. Additionally, the coding non-synonymous variant T60N in the neighbouring LTA gene has been reported to be associated with type 2 diabetes. The present study aimed to obtain a robust assessment of the role of variation in the tightly linked TNF/LTA region in diabetes susceptibility by genotyping TNF and LTA variants in large case-control resources.

MATERIALS AND METHODS

The G-308A and G-238A TNF promoter variants and the LTA T60N polymorphism were genotyped in two UK case samples that were ascertained for positive family history and/or early onset of type 2 diabetes (combined n=858) and in 1,257 ethnically matched controls.

RESULTS

There were no significant associations between the T60N, G-308A or G-238A genotype and type 2 diabetes in the combined analysis (exact Cochran-Mantel-Haenszel statistic for ordered genotypes for T60N, p=0.69; for G-308A, p=0.51; for G-238A, p=0.16).

CONCLUSIONS/INTERPRETATION

The present study, one of the largest association analyses yet reported at this locus, provides no evidence that the specific TNF or LTA variants examined influence susceptibility to type 2 diabetes. More comprehensive studies of the TNF/LTA locus in substantially larger sample sets are required to establish whether genome sequence variation at this locus truly influences susceptibility to type 2 diabetes.

Reduced density of calbindin-immunoreactive interneurons in the planum temporale in schizophrenia

Reduced density of calbindin-containing interneurons in the prefrontal cortex in schizophrenia has been reported (Beasley et al 2002; Biol Psych 52:708-715). Calbindin is a calcium-binding protein (CBP) present in a subpopulation of GABAergic neurons restricted mainly to layer II of the cortex. A paraffin-embedded, 10-mum-thick section from the planum temporale (PT) of each hemisphere was prepared from 12 patients with schizophrenia and 12 controls. Calbindin-containing cells were stained using an antibody (D-28K). Counting frames were superimposed to sample within layer II of the PT. A bilateral reduction (20%) in calbindin cell density was found in patients (controlling for fixation time). Furthermore, mean calbindin cell cross-sectional area was increased in female patients and reduced in male patients. Reduced CBP expression (reducing the excitability of interneurons) or reduced number of CBP-containing cells may cause disinhibition of pyramidal cells. The majority of calbindin-containing cells in the mature brain are double-bouquet cells with vertically oriented dendrites and axon bundles. By exercising inhibitory modulation of pyramidal cells in a columnar arrangement, they make possible cohesive vertical inhibition of minicolumns. Loss of columnar inhibition may result in reduced minicolumnar segregation and altered cell size may reflect altered minicolumn size.

Visualisation of bacterial sequestration and bactericidal activity within hydrating Hydrofiber wound dressings

The fluid handling and microbiological properties of a non-antimicrobial Hydrofiber(NAH) wound dressing have been compared with those of a silver salt-containing Hydrofiber (SCH). Fluorescent dyes (BacLight, Live/Dead Kit) were added to fresh cultures of two wound pathogens (Pseudomonas aeruginosa and Staphylococcus aureus), and used to visualise their viability. Live bacteria stained green and dead/dying bacteria turned red. When inoculated into samples of the NAH and SCH dressings, the viability of the bacteria could be effectively monitored over time using a rapid form of confocal laser scanning microscopy (RCLSM--Leica UK). When the NAH dressing was hydrated with stained bacterial culture, its fibres swelled quickly, reducing interstitial spaces between the fibres, resulting in the formation of a cohesive gel. Bacteria became immobilised in the gel, forming characteristic clumps, but remained largely green (viable) for more than 20 h with no apparent increase in numbers. The SCH initially behaved in a similar manner, however, using 3-D data from RCLSM time-lapse sequences P. aeruginosa was observed to turn progressively red (i.e. died) within 1.5-3 h and S. aureus similarly turned red within 5-7 h of contact with the SCH dressing. The ability of both Hydrofiber dressings to sequester and immobilise potentially pathogenic wound micro-organisms has been demonstrated. Additionally the SCH dressing was shown to kill immobilised bacteria, as a consequence of the ionic silver bactericide. These properties of the Hydrofiber dressings may contribute to providing an environment that is supportive to wound healing.

Inequalities in coronary revascularisation during the 1990s: evidence from the British regional heart study

OBJECTIVE

To investigate the influence of age and social circumstances on probability of revascularisation among British men.

DESIGN

Prospective population based study

SETTING

24 medium sized British towns, none of which contained a hospital undertaking coronary artery bypass surgery.

SUBJECTS

5814 surviving participants of the BRHS (British regional heart study), aged 52-73 years, with no history of revascularisation when responding to a questionnaire in November 1992.

MAIN OUTCOMES

Incident coronary revascularisations, as documented in general practitioner records, over the following 7.1 years and coronary angiography investigations reported by men in a further questionnaire in November 1996.

RESULTS

160 men underwent at least one revascularisation during this period (4.2/1000 person-years). In multifactorial analysis, which included adjustment for incidence of major coronary heart disease or angina, a lower incidence of revascularisation was found among men aged over 65 years in November 1992 (hazard ratio 0.62, 95% confidence interval (CI) 0.44 to 0.87), among men with manual occupations (0.73, 95% CI 0.53 to 1.02), among men living in households possessing no car (0.44, 95% CI 0.24 to 0.80) or one car (0.60, 95% CI 0.42 to 0.87) compared with two or more cars, among council tenants (0.49, 95% CI 0.25 to 0.97), and among men living outside southern England (0.71, 95% CI 0.51 to 0.99). Only car ownership was related to the incidence of diagnostic angiography: the odds ratio for angiography for those owning fewer than two cars was 0.62 (95% CI 0.42 to 0.89).

CONCLUSION

During the 1990s, there were major inequalities in the probability of undergoing coronary revascularisation between British men according to socioeconomic status, age, and geographic location.

Prognostic Role of a Multigene Reverse Transcriptase-PCR Assay in Patients with Node-Negative Breast Cancer Not Receiving Adjuvant Systemic Therapy

PURPOSE

To test the ability of a reverse transcriptase-PCR (RT-PCR) assay, based on gene expression profiles, to accurately determine the risk of recurrence in patients with node-negative breast cancer who did not receive systemic therapy using formalin-fixed, paraffin-embedded tissue. A secondary objective was to determine whether the quantitative RT-PCR data correlated with immunohistochemistry assay data regarding estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 status.

PATIENTS AND METHODS

We obtained archival paraffin-embedded tissue from patients with invasive breast cancer but no axillary lymph node involvement who had received no adjuvant systemic therapy and been followed for at least 5 years. RNA was extracted from three 10-microm-thick sections. The expression of 16 cancer-related genes and 5 reference genes was quantified using RT-PCR. A gene expression algorithm was used to calculate a recurrence score for each patient. We then assessed the ability of the test to accurately predict distant recurrence-free survival in this population.

RESULTS

We identified 149 eligible patients. Median age at diagnosis was 59 years; mean tumor diameter was 2 cm; and 69% of tumors were estrogen receptor positive. Median follow-up was 18 years. The 5-year disease-free survival rate for the group was 80%. The 21 gene-based recurrence score was not predictive of distant disease recurrence. However, a high concordance between RT-PCR and immunohistochemical assays for estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 status was noted.

CONCLUSIONS

RT-PCR can be done on paraffin-embedded tissue to validate the large numbers of genes associated with breast cancer recurrence. However, further work needs to be done to develop an assay to identify the likelihood of recurrent disease in patients with node-negative breast cancer who do not receive adjuvant tamoxifen or chemotherapy.

Calpain inhibition and insulin action in cultured human muscle cells

Variation in the calpain 10 gene has been reported to increase susceptibility to type 2 diabetes. Part of this susceptibility appears to be mediated by a decrease in whole body insulin sensitivity. As skeletal muscle is the primary tissue site of the peripheral insulin resistance in type 2 diabetes, the aim of this study was to use a human skeletal muscle cell culture system to explore the effects of calpain inhibition on insulin action. Calpain 10 mRNA and protein expression was examined in cultured myoblasts, myotubes, and whole skeletal muscle from non-diabetic subjects using RT-PCR and Western blotting. Changes in insulin-stimulated glucose uptake and glycogen synthesis in response to the calpain inhibitors ALLN and ALLM were measured. Calpain 10 expression was confirmed in cultured human myoblasts, myotubes, and native skeletal muscle. Insulin-stimulated glucose uptake was significantly decreased following preincubation with ALLN [404+/-40 vs 505+/-55 (mean+/-SEM)pmol/mg/min; with vs without ALLN: p = 0.04] and ALLM [455+/-38 vs 550+/-50 pmol/mg/min; with vs without ALLM: p = 0.025] in day 7 fused myotubes, but not in myoblasts. Neither ALLN nor ALLM affected insulin-stimulated glycogen synthesis in myoblasts or myotubes. These studies confirm calpain 10 expression in cultured human muscle cells and support a role for calpains in insulin-stimulated glucose uptake in human skeletal muscle cells that may be relevant to the pathogenesis of the peripheral insulin resistance in type 2 diabetes.

Whole genomewide linkage screen for neural tube defects reveals regions of interest on chromosomes 7 and 10

Neural tube defects (NTDs) are the second most common birth defects (1 in 1000 live births) in the world. Periconceptional maternal folate supplementation reduces NTD risk by 50-70%; however, studies of folate related and other developmental genes in humans have failed to definitively identify a major causal gene for NTD. The aetiology of NTDs remains unknown and both genetic and environmental factors are implicated. We present findings from a microsatellite based screen of 44 multiplex pedigrees ascertained through the NTD Collaborative Group. For the linkage analysis, we defined our phenotype narrowly by considering individuals with a lumbosacral level myelomeningocele as affected, then we expanded the phenotype to include all types of NTDs. Two point parametric analyses were performed using VITESSE and HOMOG. Multipoint parametric and nonparametric analyses were performed using ALLEGRO. Initial results identified chromosomes 7 and 10, both with maximum parametric multipoint lod scores (Mlod) >2.0. Chromosome 7 produced the highest score in the 24 cM interval between D7S3056 and D7S3051 (parametric Mlod 2.45; nonparametric Mlod 1.89). Further investigation demonstrated that results on chromosome 7 were being primarily driven by a single large pedigree (parametric Mlod 2.40). When this family was removed from analysis, chromosome 10 was the most interesting region, with a peak Mlod of 2.25 at D10S1731. Based on mouse human synteny, two candidate genes (Meox2, Twist1) were identified on chromosome 7. A review of public databases revealed three biologically plausible candidates (FGFR2, GFRA1, Pax2) on chromosome 10. The results from this screen provide valuable positional data for prioritisation of candidate gene assessment in future studies of NTDs.

PLAY-DOHR AND WATER-SOAKED GAUZE SPONGES AS ALTERNATIVE BOLUS MATERIAL FOR COBALT-60 TELETHERAPY

A study was performed to determine if carefully made boluses of either Play-Doh, or water-soaked cotton gauze sponges differed from the commercial bolus material, Superflab, in producing maximum radiation dose when irradiated with cobalt-60 photons. The radiation doses were measured with thermoluminescent dosimeters calibrated to be accurate for cobalt-60 photon energies at doses less than 10.0 cGy. The resulting radiation doses were similar when using Play-Doh, water-soaked sponges, or Superlab. Doses resulting from Play-Doh boluses more consistently approximated those of Superflab. The results of this study suggest that either Play-Doh or water-soaked cotton gauze sponges can suffice as material for carefully made bolus for cobalt-60 teletherapy.

A comparative study of the structure of human and murine greater omentum

In humans, the greater omentum is a fatty peritoneal fold that extends from the greater curvature of the stomach to cover most abdominal organs. It performs many functions, which include acting as a reservoir of resident peritoneal inflammatory cells, a storage site for lipid, and a regulator of fluid exchange in and out of the peritoneal cavity. Most importantly, the omentum readily adheres to areas of inflammation and peritoneal damage, often leading to adhesion formation. Despite its clinical importance, the omentum remains an understudied organ, and discrepancies exist as to its exact morphology. This study uses a combination of phase contrast microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) to elucidate the structure of the greater omentum of both human and mouse and determine whether it possesses a typical surface mesothelial cell lining similar to other serosa. Results indicated that both human and murine omenta were of similar structure and composed of two distinct types of tissue, one adipose-rich and the other translucent and membranous. The adipose-rich regions were well-vascularised and covered by a continuous mesothelial cell layer except at the sites of milky spots. In contrast, translucent areas were poorly vascularised and contained numerous fenestrations of varying size. The possible function and developmental origin of these gaps is unclear; however, their role in promoting omental adhesion formation and in the successful use of omental graft material is discussed.

Analysis of the contribution to type 2 diabetes susceptibility of sequence variation in the gene encoding stearoyl-CoA desaturase, a key regulator of lipid and carbohydrate metabolism

AIMS/HYPOTHESIS

Stearoyl-CoA desaturase (SCD) is emerging as a key regulator of lipid and carbohydrate metabolism. Scd-null mice display a beneficial metabolic phenotype characterised by resistance to obesity, diabetes and hyperlipidaemia. The human homologue, SCD, maps to a region of chromosome 10 linked to type 2 diabetes, and SCD activity correlates with insulin sensitivity. Given this strong positional and biological candidacy, the present study sought to establish whether sequence variation in SCD influences susceptibility to type 2 diabetes and related traits.

METHODS

The SCD gene was resequenced in 23 diabetic subjects. Six variants within coding and adjacent sequence, including a non-synonymous SNP in exon 5 (M224L), were selected for genotyping in a primary set of 608 diabetic subjects and 600 control subjects.

RESULTS

There was no association (at the allele, genotype or haplotype level) with type 2 diabetes, although genotype frequencies at the +14301 A>C SNP in the 3' untranslated region showed borderline association (p~0.06) when evidence for linkage was taken into account. However, replication studies (350 young-onset diabetic patients; 747 controls) failed to confirm any relationship with diabetes for this variant. No significant associations were seen for diabetes-related traits including BMI and waist-to-hip ratio.

CONCLUSIONS/INTERPRETATION

The present study, the first reported analysis of this gene, indicates that the SCD variants typed do not explain chromosome-10-encoded susceptibility to type 2 diabetes. Although this study provided no evidence that SCD sequence variation influences diabetes susceptibility or related traits, SCD remains a major target for pharmaceutical and/or environmental manipulation.

Myosin VI: a multifunctional motor

Myosin VI moves towards the minus end of actin filaments unlike all the other myosins so far studied, suggesting that it has unique properties and functions. Myosin VI is present in clathrin-coated pits and vesicles, in membrane ruffles and in the Golgi complex, indicating that it has a wide variety of functions in the cell. To investigate the cellular roles of myosin VI, we have identified a variety of myosin VI-binding partners and characterized their interactions. As an alternative approach, we have studied the in vitro properties of intact myosin VI. Previous studies assumed that myosin VI existed as a dimer but our biochemical characterization and electron microscopy studies reveal that myosin VI is a monomer. Using an optical tweezers force transducer, we showed that monomeric myosin VI is a non-processive motor with a large working stroke of 18 nm. Potential roles for myosin VI in cells are discussed.

Multiparametric flow cytometric analysis of inter-patient variation in STAT1 phosphorylation following interferon Alfa immunotherapy

BACKGROUND

Regulation of gene expression by signal transducer and activator of transcription 1 (STAT1) within host tissues mediates the antitumor effects of interferon alfa (IFN alpha). We used a novel flow cytometric assay to examine phosphorylation-mediated activation of STAT1 within immune effector cell subsets following in vitro or in vivo IFN alpha treatments.

METHODS

Peripheral blood mononuclear cells (PBMCs) isolated from healthy donors (n = 17) or melanoma patients (n = 19) were treated in vitro with interferon alfa-2b (IFN alpha-2b) or phosphate-buffered saline (PBS) and subjected to multiparametric flow cytometry to measure the levels of phosphorylated STAT1 (P-STAT1) within immune cell subsets. We similarly analyzed PBMCs isolated from melanoma patients before and 1 hour after immunotherapy with IFN alpha-2b. All statistical tests were two-sided.

RESULTS

P-STAT1 levels in all major immune cell subsets increased within 15 minutes of in vitro IFN alpha-2b treatment of PBMCs; the increase was most pronounced in T lymphocytes and monocytes. Relatively low doses of IFN alpha-2b (i.e., 10(2)-10(3) IU/mL) induced maximal STAT1 activation in vitro. Compared with melanoma patients, healthy donors had higher basal levels of P-STAT1 (specific fluorescence [Fsp]; i.e., Fsp(PBS), the level of P-STAT1 in PBS-treated cells) in total PBMCs, natural killer (NK) cells, and T cells (mean Fsp(PBS) in total PBMCs: 5.5 in healthy donors versus 1.6 in patients, difference = 3.9, 95% confidence interval [CI] = 1.4 to 6.5, P =.004; mean Fsp(PBS) in NK cells: 4.6 in healthy donors versus 0.9 in patients, difference = 3.7, 95% CI = 1.7 to 5.7, P =.001; mean Fsp(PBS) in T cells: 6.8 in healthy donors versus 0.9 in patients, difference = 5.9, 95% CI = 2.5 to 9.3, P =.002). P-STAT1 was detected in the NK and T cells of two patients who received IFN alpha-2b immunotherapy (20 MU/m2 [MU = million units], administered by intravenous injection). P-STAT1 levels in the PBMCs of a patient treated sequentially with 5 MU/m2 and 10 MU/m2 IFN alpha-2b (administered by subcutaneous injection) also increased in response to treatments with IFN alpha-2b but did not increase further with the increased dosage of IFN alpha-2b.

CONCLUSION

This flow cytometry method can be used to monitor STAT1 activation within subsets of immune cells from patients undergoing IFN alpha immunotherapy.

Sexual networking among married men with wives of child bearing age in Ibadan City, Nigeria: report of a pilot study

Following the Beijing Conference, it is desirable to empower men to play a more active and responsive role in promoting the health of family members and preventing disease. This cross sectional, community-based, ex-post factor, pilot study was designed to find out if traditional norms affect marital sexuality and also to identify sociodemographic factors associated with sexual networking among men. A total of 416 married men whose wives had delivered a baby in the last 36 months prior to the study were interviewed from randomly selected clusters in Ibadan, Nigeria. Of this number, the majority 336 (80.8%) had sex with pregnant wife in the last pregnancy and proportion of married men who had sex in the pregnancy with wives reduced modestly with increasing age of the men. With regards to sexual networking in pregnancy, 207 (49.8%) men reported having sex with someone else when wife was pregnant. Of this number 95 (45.9%) had it with steady girl friends, 56 (27.0%) with new girl friends, 50 (24.2%) with another wife and 6 (2.9%) with commercial sex workers. The prevalence for having sex with someone else in this period was lower in men from the higher socio-economic class (HSEC) when compared with the lower socio-economic class (LSEC)(chi2 = -9.89, P < 0.001). The middle socio-economic class also had a lower rate than the lower socio-economic class (chi2 = 6.28, P < 0.01). In addition, men with post secondary/University education had significantly lower rates for networking when their wives were pregnant compared with men of lower educational attainment (P < 0.05). Three hundred and eleven men (74.8%) reported that they observed some period ofpostpartum abstinence (PPA) with recently delivered wife, which ranged from 5 days to 72 months (Median was 7.5 months). The highest PPA rates were seen in men with no formal education, those from lower SEC and in men who embraced traditional religions. Issues that have to be addressed in more detail in the follow up study include understanding why men network as traditional proscriptions are generally not adhered to. Determining the relationship between length of postpartum abstinence and sexual networking and implication of this behaviour in the spread of sexually transmitted diseases and fertility control if postpartum abstinence period is significantly reduced or increased. In this regard, qualitative research as well as quantitative research should be carried out so that the entire study is not left within the realm of a quantitative study, which may be inadequate for explaining social and demographic data.

Overweight and obesity and the burden of disease and disability in elderly men

OBJECTIVE

To examine the prevalence of disease burden and disability associated with overweight and obesity in men aged 60-79 y and to assess whether the current WHO weight guidelines are appropriate in the elderly.

DESIGN

Cross-sectional survey 20 y after enrollment.

SETTING

General practices in 24 British towns.

PARTICIPANTS

In total, 4232 men aged 60-79 y (77% of survivors) with measured weight and height.

MAIN OUTCOME MEASURES

Cardiovascular (CV) risk factors, prevalence of diabetes, cardiovascular disease, cancer, disability and regular medication.

RESULTS

In total, 17% of the men were obese (body mass index (BMI) >/=30 kg/m(2)) and a further 52% were overweight (BMI 25-29.9 kg/m(2)). Prevalence of hypertension, low HDL-cholesterol, high triglycerides and insulin resistance and the prevalence of most disease outcomes increased with increasing degrees of overweight/obesity. Men in the normal weight range (18.5-24.9 kg/m(2)) had the lowest prevalence of ill health. Compared with normal weight men, obese men showed a two-fold risk of major CVD (odds ratio (OR)=1.96, 95% CI 1.44-2.67) and locomotor disability (OR=2.26, 95% CI 1.66, 3.09) and were nearly three times as likely to have diabetes, CV interventions or to be on CV medication. Over 60% of the prevalence of high insulin resistance was attributable to overweight and obesity as was over a third of diabetes and hypertension, a quarter of locomotor disability and a fifth of major CVD.

CONCLUSION

In elderly men, overweight and obesity are associated with a significantly increased burden of disease, in particular CV-related disorders and disability. The current guidelines for overweight and obesity appear to be appropriate in elderly men.