γ-Synuclein Expression Is a Malignant Index in Oral Squamous Cell Carcinoma.

Dysregulation of γ-synuclein (SNCG) has been reported in many cancers; however, its role in cancer development is still controversial. Here, we examined the potential involvement of DNA methylation in regulating SNCG and its role in oral squamous cell carcinoma (OSCC). We used 8 OSCC cell lines to investigate SNCG methylation and expression. SNCG methylation was examination by methylation-specific polymerase chain reaction and bisulfate sequencing. Cells showing a high degree of SNCG methylation were treated with 5-aza (methylation inhibitor), and changes in their methylation and expression profiles were analyzed. Functional effects of SNCG in OSCC were examined by its overexpression and knockdown. Additionally, methylation and expression of SNCG in OSCC tissues were investigated and correlated with clinicopathologic features. All OSCC cells showed detectable SNCG expression at the mRNA and protein levels. Methylation-specific polymerase chain reaction and bisulfate sequencing revealed high SNCG expression in SCC25 cells with the unmethylated allele, and their 15 CpG islands were unmethylated. The methylated allele was detected only in OEC-M1 cells exhibiting low SNCG expression, and their CpG islands were partially methylated. 5-aza treatment in OEC-M1 cells attenuated methylation and restored SNCG expression. SNCG overexpression increased colony forming, migration, and invasion abilities in OEC-M1 cells. Silencing SNCG in SCC25 cells suppressed these behaviors. All 25 tumor-adjacent normal tissues were negative for SNCG immunostaining. SNCG upregulation was frequently observed in dysplastic and OSCC tissues. Positive SNCG expression was found in 45% (37 of 82) OSCC tissues. Positive SNCG expression in OSCC significantly correlated with cancer staging and lymph node metastasis. However, SNCG methylation did not correlate with its expression and clinicopathologic variables in OSCC tissues. DNA methylation may participate in regulating SNCG expression in some OSCC cells. SNCG upregulation could be involved in OSCC progression.

Patients' beliefs and behaviors related to treatment adherence in patients with asthma requiring maintenance treatment in Asia.

OBJECTIVES: To identify patients' beliefs or behaviors related to treatment adherence and to assess association between asthma control and adherence in Asian patients with asthma. METHODS: We conducted a cross-sectional observational study of adult patients with asthma from specialist clinics in six Asian countries. Patients who were deemed by their treating physicians to require a maintenance treatment with an inhaler for at least 1 year were recruited. Patients completed a 12-item questionnaire related to health beliefs and behaviors, the 8-item Morisky Medication Adherence Scale (MMAS-8), the Asthma Control Test (ACT™), and the Standardized Asthma Quality of Life Questionnaire (AQLQ-S). RESULTS: Of the 1054 patients recruited, 99% were current users of inhaled corticosteroids. The mean ACT score was 20.0 ± 4.5 and 64% had well-controlled asthma. The mean MMAS-8 score was 5.5 ± 2.0 and 53% were adherent. Adherence was significantly associated with patients' understanding of the disease and inhaler techniques, and with patients' acceptance of inhaler medicines in terms of benefits, safety, convenience, and cost (p < 0.01 for all). In multivariate analysis, three questions related to patients' acceptance of inhaler medicines remained significantly associated with poor adherence, after adjusting for potential confounders: "I am not sure inhaler type medicines work well" (p = 0.001), "Taking medicines more than once a day is inconvenient" (p = 0.002), and "Sometimes I skip my inhaler to use it over a longer period" (p < 0.001). CONCLUSIONS: Our study showed that patients' acceptance of the benefits, convenience and cost of inhaler medications have a significant impact on treatment adherence in the participating Asian countries.

Interaction of the G182C polymorphism in the APOA5 gene and fasting plasma glucose on plasma triglycerides in Type 2 diabetic subjects.

AIM: Apolipoprotein AV (APOA5) is an important determinant of plasma triglyceride concentration. This study aimed to investigate the relationship of an amino acid substitution at position 182 (G182C) of the apolipoprotein AV (APOA5) gene with triglyceride concentration in a Taiwanese population. METHODS: This study enrolled two cohorts: non-diabetic subjects (112 males and 89 females) aged 50.3+/-11.0 years (mean+/-sd) and diabetic subjects (106 males and 96 females) aged 62.1+/-10.3 years. The relationship between the G182C polymorphism (rs 2075291) and plasma triglycerides was examined. Demographic and metabolic parameters including age, sex, body mass index, fasting plasma glucose and total cholesterol were also obtained. RESULTS: The G182C polymorphism was a determinant of plasma triglycerides in both non-diabetic (P=0.022) and diabetic (P=0.003) groups, independent of age, gender, fasting plasma glucose, body mass index and total cholesterol. In the diabetic group, this genetic polymorphism interacts significantly (P=0.032) with fasting plasma glucose concentration on plasma triglycerides after adjustment for age, sex, body mass index and total cholesterol. CONCLUSIONS: In conclusion, the G182C polymorphism of the APOA5 gene affects plasma triglycerides in both non-diabetic and diabetic populations. The observed interaction of gene and glycaemic control further indicates a multifactorial nature of clinical phenotypes in subjects with Type 2 diabetes.

Transcription factor 1 and beta-cell function in glucose-tolerant subjects.

AIMS: Although beta-cell dysfunction and insulin resistance are observed in patients with Type 2 diabetes, beta-cell dysfunction plays a crucial role in the development of the disease. Mutations of transcription factor 1 (TCF1, or hepatocyte nuclear factor-1alpha) affect beta-cell function. We examined the impact of amino acid polymorphisms of this gene on beta-cell function in 60 glucose-tolerant Caucasians. METHODS: Insulin sensitivity index (ISI) and 1st and 2nd phase insulin responses (1stIR, 2ndIR) were measured using the hyperglycaemic clamp. The genotypes were determined from genomic DNA and their impact on beta-cell function was investigated. RESULTS: Among three polymorphisms (I27L, A98V, and S487N), significant impact on beta-cell function was found in the I27L polymorphism. Univariate analyses revealed differences for the I27L polymorphism in both 1stIR (P = 0.0052) and 2ndIR (P = 0.0432). Multivariate analysis revealed that the I27L polymorphism (P = 0.0124) with ISI accounted for 32% of the variation in 1stIR and had a marginal impact on 2ndIR (P = 0.0343), accounting for 52% of the variation with ISI and age. By dissecting out the impact of other covariate(s), the I27L polymorphism independently explained 12% of the variation in 1stIR and 6% of the variation in 2ndIR. CONCLUSION: The I27L polymorphism of TCF1 is an independent determinant of beta-cell function by affecting both 1st and 2nd phase insulin response. This polymorphism could play a role in the pathogenesis of Type 2 diabetes. A large-scale association study (approx. 2000 subjects) will be required to demonstrate the genetic susceptibility of this polymorphism to Type 2 diabetes.

Molecular scanning of the human sorbin and SH3-domain-containing-1 (SORBS1) gene: positive association of the T228A polymorphism with obesity and type 2 diabetes.

In the mouse, the SH3P12 or the c-Cbl-associated protein (CAP) has been shown as an important signaling molecule in insulin-stimulated glucose uptake. The human homolog for the sorbin and SH3-domain-containing-1 gene, termed SORBS1, might play a role in human disorders with insulin resistance. To explore the genetic role of SORBS1 in human obesity and type 2 diabetes, we investigated the nucleotide polymorphisms in the SORBS1 gene with molecular scanning. After scanning for a total of 13,136 bp in each of 40 chromosomes, we have identified 14 single nucleotide polymorphisms (SNPs) in the human SORBS1 gene. Among them, two SNPs affected amino acid coding (R74W and T228A), four occurred within exons but did not affect amino acid coding, and the remaining eight occurred within introns, which were located outside of the consensus region of the splicing mechanism. Further studies in 202 non-obese, 113 obese and 455 subjects with type 2 diabetes revealed that the A-allele of the T228A polymorphism in exon 7 exerted a protective role for both obesity [relative risk 0.466; 95% confidence interval (95% CI) 0.265-0.821] and diabetes (relative risk 0.668; 95% CI 0.472-0.945). Neither allele of the R74W polymorphism was associated with either obesity or diabetes. In conclusion, our results suggest that the A228 allele of the T228A polymorphism of the SORBS1 gene is a protective factor for both obesity and diabetes, and also imply that the SORBS1 gene plays an important role in the pathogenesis of human disorders with insulin resistance.

Fatty acid binding protein 2 and insulin resistance.

BACKGROUND: An A54T polymorphism of the fatty acid binding protein 2 (FABP2) gene was found to be associated with insulin resistance in nondiabetic Pima Indians. Design This is a cross-sectional study to examine the role of this polymorphism in insulin resistance in 71 healthy and normotensive Caucasian subjects with normal glucose tolerance. Insulin sensitivity (%S, ISI(M), ISI(S)) and beta-cell function (%B, dI/dG, 1stPHS, 2ndPHS) were estimated based on published models. Their genotypes were determined using a polymerase chain reaction-restriction fragment length polymorphism assay. The relationship between genotypes and phenotypes was examined. RESULTS: After genotyping, we identified 34 AA, 32 AT and five TT subjects. The TT subjects were pooled together with the AT subjects during the analysis due to their low number. No difference was noted in gender distribution, clinical features, or fasting lipid profile between the two genotypic groups (AA vs. AT/TT). The AT/TT group had lower %S and ISI(S) than the AA group (P = 0.0118 and P = 0.0170, respectively). The difference in ISI(M) was marginal (P = 0.0544). However, no difference was noted in beta-cell function between the two groups. Multivariate analysis revealed that this polymorphism was an independent but modest determinant for %S (P = 0.0149), ISI(M) (P = 0.0489) and ISI(S) (P = 0.0175). It independently contributed 6.04% (95% CI, 0.02-20.53%), 4.28% (95% CI, 0.08-17.63%) and 4.94% (95% CI, 0.01-18.75%) of the variation of %S, ISI(M) and ISI(S), respectively. CONCLUSIONS: We demonstrated that the A54T polymorphism at the FABP2 locus is a risk factor for insulin resistance in a Caucasian population.

A randomized controlled trial of low-dose recombinant human growth hormone in the treatment of malnourished elderly medical patients.

High-dose recombinant human GH (rhGH) has been shown to improve the nutritional status of malnourished older adults. It is uncertain whether low-dose rhGH is effective and whether its effect on nutritional status will lead to any improvement in physical function. There is also no data on the outcome after a short course of rhGH treatment. The objectives of this study were to determine the efficacy of low-dose rhGH treatment for 4 weeks in malnourished elderly patients, its effect on physical functions, and the intermediate term outcome after a 4-week rhGH treatment. The study design was a randomized, placebo-controlled, double-blind trial conducted in a university teaching hospital. The patients were 19 medically stable malnourished elderly subjects. Intervention in the rhGH group was as follows: rhGH (Saizen, Serono, Switzerland) 0.09 IU/kg body weight (BW) 3 times weekly were given together with appropriate dietary intervention as prescribed by the dietitian. In the placebo group, equal volumes of normal saline per kilogram BW were given 3 times weekly together with the dietary intervention. The baseline demographic, anthropometric, nutritional, and hematological variables, measures of physical function, and insulin-like growth factor I levels in both groups were comparable. Compared with the placebo group, the GH-treated group showed a more rapid gain in BW (after 3 weeks, +1.27 +/- 0.36 vs. -0.28 +/- 0.37 kg; P = 0.008), total lean body mass (change after 3 weeks by bio-impedance analysis, +1.45 +/- 0.36 vs. -0.37 +/- 0.48 kg; P = 0.009) and a faster improvement in 5-m walking time (decrease after 4 weeks, 23.79 +/- 9.41 vs. 0.45 +/- 4.62 sec; P = 0.047). The hemoglobin level rose more in the rhGH than the placebo groups (change at 8 weeks, +0.84 +/- 0.34 vs. -0.42 +/- 0.29 g/dL; P = 0.012). Serum albumin level also showed a greater delayed increase in the rhGH group than in the placebo group (change at 8 weeks, +5.1 +/- 0.8 vs. 1.6 +/- 1.2 g/dL; P = 0.023). There was no statistically significant difference for other nutritional variables. There was a greater rise in the mean serum insulin-like growth factor I level at 4 weeks in the GH than in the placebo groups (197 +/- 58 vs. 54 +/- 26 U/L; P = 0.034). The improvement in the rhGH group gradually diminished on follow-up and became statistically insignificant 8 weeks after stopping rhGH treatment. There were no GH-related adverse effects. Low-dose rhGH was an effective and safe adjuvant to dietary augmentation for stable malnourished elderly subjects. It led to a faster gain in total lean body mass, which was associated with greater improvement in walking speed when compared with dietary intervention alone. There were no apparent side effects.

Comparison of measured and estimated indices of insulin sensitivity and beta cell function: impact of ethnicity on insulin sensitivity and beta cell function in glucose-tolerant and normotensive subjects.

Type 2 diabetes mellitus is the result of an imbalance between insulin sensitivity and beta cell function. Although the assessment of these 2 parameters is critical for various studies, the current methods are time consuming and labor intensive. Recently, new estimated indices have been proposed. We examined the impact of ethnicity on the indices of insulin sensitivity and beta cell function measured from the hyperglycemic clamp and compared the results to the estimated indices, proposed by Matsuda and DeFronzo and Stumvoll et al., from a standard oral glucose tolerance test in 105 healthy, glucose-tolerant, and normotensive subjects from 4 ethnic groups. Among the ethnic groups, differences were noted in the measured insulin sensitivity (P = 0.0006) and beta cell function (P = 0.006 for the first phase insulin response, P = 0.0002 for the second phase insulin response). Although the estimated indices correlated with the measured indices (r(2) = 0.5184--0.3014), the estimated indices barely detected the differences among the ethnic groups. Multivariate analysis confirmed that ethnicity had an independent impact for the measured indices, but had only a modest impact on the estimated insulin sensitivity indices and had no impact on the estimated indices of beta cell function. We conclude that although the estimated indices of insulin sensitivity and beta cell function from the oral glucose tolerance test correlated with the measured ones in a wide spectrum of healthy, glucose-tolerant, and normotensive subjects, they were much less likely to detect the differences than measured ones among the ethnic groups.

The A54T polymorphism at the intestinal fatty acid binding protein 2 is associated with insulin resistance in glucose tolerant Caucasians.

BACKGROUND: An A54T polymorphism at the fatty acid binding protein 2 (FABP2) locus was found to be associated with insulin resistance in non-diabetic Pima Indians. To see whether this association is present in other populations, we performed a cross sectional study to examine the role of this polymorphism on insulin resistance in 55 healthy and normotensive Caucasian subjects with normal glucose tolerance. Insulin sensitivity (%S) and beta cell function (%B) were assessed using the Homeostasis Model Assessment (HOMA). Their genotypes were determined using a polymerase chain reaction-restriction fragment length polymorphism assay. The relationship between the genotypes and the phenotypes was examined. RESULTS: After genotyping, we identified 24 AA, 27 AT and 4 TT subjects. The TT subjects were combined with the AT subjects during the analysis due to its small sample size. No differences were noted in gender distribution, clinical features, and fasting lipid profile between the two genotypic groups (AA vs. AT/TT). The AT/TT group had a higher fasting plasma insulin concentration and a lower %S than the AA group (p = 0.0444 and p = 0.0461, respectively). However, no differences were noted in plasma glucose concentrations and %B. Univariate analysis revealed that this polymorphism explained 7.3% of the variation in %S. Multivariate analysis revealed that the polymorphism was an independent determinant for %S (p = 0.0434) and with body mass index accounted for 28.7% of the variation in %S. In contrast, this polymorphism had no impact on %B. CONCLUSIONS: The A54T polymorphism at the FABP2 locus is a risk factor for insulin resistance in a Caucasian population.

The vitamin D receptor polymorphism in the translation initiation codon is a risk factor for insulin resistance in glucose tolerant Caucasians.

BACKGROUND: Although vitamin D receptor (VDR) polymorphisms have been shown to be associated with abnormal glucose metabolism, the reported polymorphisms are unlikely to have any biological consequences. The VDR gene has two potential translation initiation sites. A T-to-C polymorphism has been noted in the first ATG (f allele), abolishing the first translation initiation site and resulting in a peptide lacking the first three amino acids (F allele). We examined the role of this polymorphism in insulin sensitivity and beta cell function. This study included 49 healthy Caucasian subjects (28 females, age 28 +/- 1 years old, body mass index 24.57 +/- 0.57 kg/m2, waist-hip ratio 0.81 +/- 0.01 cm/cm). They were all normotensive (less than 140/90 mmHg) and glucose tolerant, which was determined by a standard 75-gm oral glucose tolerance test. Their beta cell function (%B) and insulin sensitivity (%S) were calculated based on the Homeostasis Model Assessment (HOMA). Their genotypes were determined by a polymerase chain reaction-restriction fragment length polymorphism analysis. Phenotypes were compared between genotypic groups. RESULTS: There were 18 FF, 21 Ff, and 10 ff subjects. Since only 10 ff subjects were identified, they were pooled with the Ff subjects during analyses. The FF and Ff/ff groups had similar glucose levels at each time point before and after a glucose challenge. The Ff/ff group had higher insulin levels than the FF group at fasting (P=0.006), 30 minutes (P=0.009), 60 minutes (P=0.049), and 90 minutes (P=0.042). Furthermore, the Ff/ff group also had a larger insulin area under the curve than the FF group (P=0.009). While no difference was noted in %B, the Ff/ff group had a lower %S than the FF group (0.53 vs. 0.78, P=0.006). A stepwise regression analysis confirmed that the Fok I polymorphism was an independent determinant for %S, accounting for 29.3% of variation in %S when combined with waist-hip ratio. CONCLUSIONS: We report that the Fok I polymorphism at the VDR gene locus is associated with insulin sensitivity, but has no influence on beta cell function in healthy Caucasians. Although this polymorphism has been shown to affect the activation of vitamin D-dependent transcription, the molecular basis of the association between this polymorphism and insulin resistance remains to be determined.

Hepatic glucokinase promoter polymorphism is associated with hepatic insulin resistance in Asian Indians.

BACKGROUND: The role of glucokinase (GCK) in the pathogenesis of maturity-onset diabetes of the young is well established. However, its role in the common form of type 2 diabetes is far from convincing. We investigated the role of the G-to-A polymorphism in the hepatic GCK promoter on insulin sensitivity and beta cell function in 63 normotensive Asian Indians with normal glucose tolerance. As proposed by Matsuda and DeFronzo, hepatic insulin sensitivity (ISIH) and total body insulin sensitivity (ISIM) were estimated from the oral glucose tolerance test. Beta cell function was estimated using %B from the Homeostasis Model Assessment and insulingenic index (dI/dG). RESULT: We identified 38 GG, 24 GA, and one AA subjects. The AA subject was pooled with the GA subjects during the analysis. No difference was noted in the demographic features between the two genotypic groups (GG vs. GA/AA). Compared to the GG group, the GA/AA group had a lower ISIH (p=0.002), a lower ISIM (p=0.009), a higher %B (p=0.014), and a higher dI/dG (p=0.030). Multivariate analysis revealed that this polymorphism is an independent determinant for ISIH (p=0.019) and along with age, waist-hip ratio, gender, and diastolic blood pressure accounted for 51.5% of the variation of ISIH. However, this polymorphism was a weak, but independent determinant for ISIM (p=0.089) and %B (p=0.083). Furthermore, it had no independent effect on dI/dG (p=0.135). CONCLUSIONS: These data suggest that the G-to-A polymorphism in the hepatic GCK promoter is associated with hepatic insulin resistance in Asian Indians.

Beta cell function declines with age in glucose tolerant Caucasians.

OBJECTIVE: As type 2 diabetes results from an imbalance between insulin sensitivity and beta cell function, either or both may worsen with age. However, existing data are controversial on the effect of ageing on both insulin sensitivity and beta cell function. SUBJECTS AND DESIGN: We enrolled 149 healthy, glucose tolerant and normotensive Caucasians (age 35 +/- 1 years, body mass index 26.07 +/- 0.44 kg/m2, waist-hip ratio 0.842 +/- 0.009 cm/cm, mean +/- standard error). A cross-sectional study was designed to examine the impact of age on insulin sensitivity and beta cell function. Their beta cell function (percentage B [%B]) and insulin sensitivity (percentage S [%S]) were estimated using the homeostasis model assessment. RESULTS: Simple regression analysis revealed that %B declined with age (P = 0.008) while no relation was found between %S and age (P = 0.769). A stepwise regression analysis revealed that body mass index and diastolic blood pressure explained 14.7% of variation in %S, while age, waist-hip ratio, gender, and systolic blood pressure had no influence on %S. Age, body mass index and diastolic blood pressure together accounted for 21.7% of variation in %B, with age being an independent variable. CONCLUSIONS: In the present study, we showed that beta cell function declined with age at a rate of about 1% per year. In contrast, insulin sensitivity was not affected by ageing. Our observations suggest that the age-related decline in glucose tolerance is primarily related to the loss of beta-cell function.

Insulin sensitivity is inversely correlated with plasma intact parathyroid hormone level.

Abnormal glucose metabolism and a high prevalence of diabetes have been reported in patients with primary and secondary hyperparathyroidism. We hypothesize that plasma intact parathyroid hormone (iPTH) level is a determinant of either insulin sensitivity or beta-cell function. The study included 52 normotensive, healthy subjects with glucose tolerance. Insulin sensitivity and beta-cell function were assessed using a hyperglycemic clamp. Fasting plasma iPTH was determined. The relationships between its level and insulin sensitivity index and beta-cell function were examined. Insulin sensitivity index was inversely correlated with plasma iPTH level (r2 = .104, P = .020). The first phase insulin response was positively correlated with plasma iPTH level (r2 = .098, P = .023), but no correlation existed with the second phase insulin response. After adjusting for age, gender, ethnicity, and waist-to-hip ratio, plasma iPTH level was an independent determinant of insulin sensitivity index (P = .019). However, no independent relationship between plasma iPTH level and beta-cell function (the first phase and second phase insulin response) was found. In normotensive, glucose-tolerant, and healthy subjects, plasma iPTH level accounts for 10.4% of the variation in insulin sensitivity index. For each pg/mL increment in plasma iPTH level, there is a decrease of 0.247 micromol/L/m2/min/pmol/L in insulin sensitivity index. Although the molecular basis of this relationship is not clear, our results indicate that plasma iPTH level is inversely correlated with insulin sensitivity index.

The reliability and validity of the Alzheimer's Disease Assessment Scale Cognitive Subscale (ADAS-Cog) among the elderly Chinese in Hong Kong.

INTRODUCTION: The Alzheimer's Disease Assessment Scale cognitive subscale (ADAS-cog) was reported to be a sensitive cognitive function assessment scale for Alzheimer's Disease (AD). The English, Greek, Spanish but not Chinese versions had been validated previously. OBJECTIVES: The objectives of the present study were to investigate the reliability and validity of an adapted Chinese version of the ADAS-cog among Chinese elderly AD patients in Hong Kong. MATERIALS AND METHOD: Thirty-nine subjects were recruited during the period July to December 1998. Twenty were AD patients while 19 were non-demented normal subjects. Two raters administered the ADAS-cog scale thrice on different occasions. RESULTS: The internal consistency (Cronbach's alpha) of the ADAS-cog were 0.91, 0.88 and 0.65 for the whole group, the AD and normal (i.e. non-demented) subjects respectively. The test-retest reliability as measured by the Spearman's rho correlation coefficients were 0.96, 0.86 and 0.86 for the whole group, AD and normal subjects, respectively, (all P < 0.001). The Spearman's rho correlation coefficients for inter-rater reliability were 0.95 (P < 0.001), 0.91 (P < 0.001) and 0.65 (P = 0.003) for the whole group, AD and normal subjects, respectively. The ADAS-cog score was inversely related to the Mini-Mental Status Examination (MMSE) score (Spearman's rho = -0.91; P < 0.001). The ADAS-cog score was directly proportional to the Clinical Dementia Rating (CDR) (rho = 0.89; P < 0.001). Forward stepwise discriminant function analysis between AD and normal subjects yielded a canonical discriminant function with 3-question items (i.e. word recall test, orientation and comprehension of speech; P < 0.001). This short version had a sensitivity of 90%, specificity of 94.7% and overall accuracy of 92.3%. CONCLUSION: The Chinese version of ADAS-cog subscale is both reliable and valid among the elderly Chinese in Hong Kong.

Insulin sensitivity differs among ethnic groups with a compensatory response in beta-cell function.

OBJECTIVE: A drastic difference is evident in the prevalence of type 2 diabetes among ethnic groups. We examined the role of beta-cell function and insulin sensitivity in this disparity among 4 ethnic groups. RESEARCH DESIGN AND METHODS: beta-Cell function and insulin sensitivity were assessed in 77 healthy glucose-tolerant subjects using a hyperglycemic clamp (18 Asian-Americans, 9 African-Americans, 34 Caucasians, and 16 Mexican-Americans). RESULTS: A wide range of variation was evident in clinical features of the studied subjects. Insulin sensitivity index and the second-phase insulin response differed among the 4 groups (P = 0.0023 and P = 0.0082, respectively), whereas the first-phase insulin response was marginally different (P = 0.1090). Stepwise regression analysis revealed that ethnicity was an independent determinant for the insulin sensitivity index (P = 0.0014) after adjusting for sex, age, diastolic blood pressure, waist-to-hip ratio, and BMI. Also, a compensatory response of beta-cell function was observed among the ethnic groups. CONCLUSIONS: In this study, we observed a drastic difference in insulin sensitivity among the different ethnic groups and observed that their beta-cell function compensates for the prevailing insulin sensitivity. The difference in the prevalence of abnormal glucose tolerance in different ethnic groups could be a result of differences in insulin sensitivity

The I27L amino acid polymorphism of hepatic nuclear factor-1alpha is associated with insulin resistance.

Mutations of the hepatic nuclear factor-1alpha (HNF-1alpha) gene have been found in patients with maturity-onset diabetes of the young. We examined the relation between the I27L polymorphism of HNF-1alpha and insulin sensitivity and beta-cell function assessed by a hyperglycemic clamp. This study included 52 healthy glucose-tolerant and normotensive subjects (age, 19-40 yr; body mass index, 17.58-35.61 kg/m2; waist/hip ratio, 0.65-1.03). We identified 19 LL subjects, 24 IL, and 9 II subjects. No difference was noted in the demographic features among the three genotypes. The LL group had the highest postchallenge insulin levels at 30 and 90 min (P = 0.038 and P = 0.015, respectively) and also the highest insulin area under curve (P = 0.009) among the three genotypes. The LL group was more insulin resistant than the IL and II groups (P = 0.042 for insulin sensitivity index). After adjusting for age, gender, obesity, and ethnicity, the I27L polymorphism was an independent determinant of the insulin sensitivity index (P = 0.001). However, it had no impact on either the first or second phase insulin response. Therefore, we conclude that the I27L polymorphism is associated with insulin resistance, but not beta-cell function. The mechanism of this association is unclear, but HNF-1alpha may play a role in regulating hepatic glucose metabolism.

Fish oil modulates macrophage P44/P42 mitogen-activated protein kinase activity induced by lipopolysaccharide.

BACKGROUND: Mitogen-activated protein kinase (MAPK) cascades represent a major signal system to transduce extracellular signals into cellular responses. Overactivity of MAPK has been implicated in the development of many diseases, including cancer and sepsis. This study investigated the hypothesis that fish oil altered the membrane phospholipid composition and modulated MAPK activity. METHODS: RAW 264.7 cells, a mouse macrophage (Mphi) cell line, were grown in eicosapentaenoic acid (EPA)-rich media (114 micromol/L) for 48 hours. Mphi were washed and exposed to Escherichia coli lipopolysaccharide (LPS; 1 microg/mL) for 10 minutes. Both total and activated (phosphorylated) portions of MAPK (P44 and P42) were determined by Western blot assays. AP-1 transcription factor activity was determined by electrophoretic mobility gel shift assays (EMSA). Mphi tumor necrosis factor (TNF) mRNA expression was measured by Northern blot assays. RESULTS: LPS stimulation induced RAW cell phosphorylation of P44/P42. In contrast, RAW cells grown in EPA-rich media had less P44/P42 activation in the presence of LPS. Total P44/P42 were not affected by EPA or LPS. Similarly, EPA also inhibited AP-1 activity. Inhibition of P44/P42 activity with PD98059 reduced both AP-1 activity and TNF mRNA expression of LPS-stimulated Mphi. CONCLUSIONS: Our data suggest that fish oil regulates macrophage proinflammatory gene activation, at least in part, by modulating the MAPK activity.

Vitamin D receptor gene polymorphisms influence susceptibility to type 1 diabetes mellitus in the Taiwanese population.

OBJECTIVE: Vitamin D and its receptor have been suggested to play a role in the pathogenesis of type 1 diabetes mellitus. We have therefore studied the influence of vitamin D receptor (VDR) gene polymorphisms on susceptibility to type 1 diabetes, and rates of glutamic acid decarboxylase (GAD65) autoantibody and islet cell autoantibody (ICA512) positivity. SUBJECTS: AND MEASUREMENTS One hundred and fifty-seven type 1 diabetic patients and 248 unrelated normal controls were recruited for this study. Genomic DNA was extracted from peripheral blood leucocytes. All type 1 diabetic patients and controls were genotyped using polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP), for three restriction sites in the VDR gene, BsmI, ApaI and TaqI. The chi2 test was used to compare the frequency of the VDR gene polymorphisms in patients and normal controls. The association of VDR gene polymorphisms in type 1 diabetes with the presence of GAD65 and ICA512 autoantibodies were also examined using the chi2 test. RESULTS: The allele frequency of the BsmI and ApaI polymorphisms, but not TaqI polymorphism, differed between patients and controls (BsmI P = 0.015; ApaI P = 0.018; TaqI P = 0.266). However, after correction for the three different polymorphisms tested, only the BsmI was significant (pc = 0.045). CONCLUSIONS: Vitamin D receptor gene polymorphisms were associated with type 1 diabetes in a Taiwanese population. However, functional studies are needed to establish the role of the vitamin D receptor in the pathogenesis of type 1 diabetes mellitus.

Fish oil augments macrophage cyclooxygenase II (COX-2) gene expression induced by endotoxin.

BACKGROUND: Fish oil-supplemented diets have anti-inflammatory and immunomodulating effects. Although fish oil is readily incorporated into the cell membrane and influences the production of eicosanoids, the exact mechanism is not clear. This study was designed to investigate the effects of eicosapentaenoic acid (EPA), a major component of fish oil, on macrophage (Mphi) cyclooxygenase (COX) gene expression induced by LPS. METHODS: RAW 264.7 cells, a mouse Mphi cell line, were grown in EPA-rich media for 24 h. Mphi were washed and exposed to Escherichia coli LPS (10 microg/ml). Membrane lipid profile was determined by gas chromatographic analysis. COX-1 and COX-2 mRNA expressions were determined by Northern blot assays with mouse-specific cDNA probes. PGE(2) production of Mphi was measured by ELISA. Mphi production of COX-2 protein was determined by Western blot assays with an anti-COX-2 antibody. RESULTS: Incubation in EPA-rich media increased membrane EPA and decreased arachidonic acid (AA) composition. COX-2 mRNA expression was induced by EPA and further augmented by LPS stimulation. EPA also augmented Mphi production of COX-2 protein. In comparison, COX-1 mRNA expression was not affected by either LPS stimulation or EPA incubation. EPA reduced PGE(2) production by LPS-stimulated Mphi. To further support that COX-2 mRNA was regulated by COX product, exogenous PGE(2) was added to Mphi prior to LPS stimulation. PGE(2) reduced COX-2 mRNA of LPS-stimulated Mphi. CONCLUSION: EPA displaces AA and reduces PGE(2) production by LPS-stimulated Mphi. Fish oil inhibition of Mphi PGE(2) production induces COX-2 mRNA expression through a COX-2 product-mediated feedback mechanism.