Increased Interaction With Insulin Receptor Substrate 1, a Novel Abnormality in Insulin Resistance and Type 2 Diabetes

Insulin receptor substrate 1 (IRS1) is a key mediator of insulin signal transduction. Perturbations involving IRS1 complexes may lead to the development of insulin resistance and type 2 diabetes (T2D). Surprisingly little is known about the proteins that interact with IRS1 in humans under health and disease conditions. We used a proteomic approach to assess IRS1 interaction partners in skeletal muscle from lean healthy control subjects (LCs), obese insulin-resistant nondiabetic control subjects (OCs), and participants with T2D before and after insulin infusion. We identified 113 novel endogenous IRS1 interaction partners, which represents the largest IRS1 interactome in humans and provides new targets for studies of IRS1 complexes in various diseases. Furthermore, we generated the first global picture of IRS1 interaction partners in LCs, and how they differ in OCs and T2D patients. Interestingly, dozens of proteins in OCs and/or T2D patients exhibited increased associations with IRS1 compared with LCs under the basal and/or insulin-stimulated conditions, revealing multiple new dysfunctional IRS1 pathways in OCs and T2D patients. This novel abnormality, increased interaction of multiple proteins with IRS1 in obesity and T2D in humans, provides new insights into the molecular mechanism of insulin resistance and identifies new targets for T2D drug development.     

Effects of choline deficiency and methotrexate treatment upon liver folate content and distribution

We examined the effects of feeding rats a choline deficient diet, of treating rats with low doses of methotrexate (MTX, 0.1 mg/kg, daily), and of combined choline deficiency and MTX treatment upon the content and distribution of folates in liver. We used a newly devised technique for analysis of folates which utilized affinity chromatography followed by high pressure liquid chromatography. Compared to control rats, total hepatic folate content decreased by 31% in the choline deficient rats, by 48% in the MTX treated rats, and by 60% in rats which were both choline deficient and treated with MTX. In extracts of livers from control rats, folates were present predominantly as penta (35%) and hexaglutamyl (52%) derivatives. The pteridine ring structure distribution of these folates was as follows: 48% 5-methyltetrahydrofolate, 14% formylated tetrahydrofolate, and 39% tetrahydrofolate. In choline deficient animals, there was a decrease in the relative concentration of pentaglutamyl folates and an increase in the relative concentration of heptaglutamyl folates. In livers from MTX treated animals, MTX-polyglutamates with 2-5 glutamate residues accumulated. The consequences of MTX treatment were: a) an elongation of the glutamate chains of the folates as the proportion of hepta- and octaglutamyl derivatives was increased relative to penta- and hexaglutamyl folates; b) the occurrence of unreduced folic acid; c) a decrease in the relative concentration of 5-methyltetrahydrofolate and an increase in the relative concentration of formylated tetrahydrofolate, and d) no change in the relative concentrations of tetrahydrofolate. In livers from animals that were both choline deficient and treated with MTX, the tetrahydrofolate concentrations were 50% of control while formylated tetrahydrofolate concentrations increased 3-fold. These data are discussed from the standpoint of the current understanding of mechanisms that regulate the elongation of the glutamic acid chains of folates and those that regulate folate dependent synthesis and utilization of one carbon unit.     

Sitagliptin and metformin--novel combination therapy

INTRODUCTION: The historical background of the discovery of incretins became of particular interest when insulin response was found to be much more pronounced when glucose was given orally, rather than intravenously. The robust insulin secretion seen in response to oral glucose, as opposed to intravenous glucose, is due to incretin hormones. Since the discovery of incretins, the significance of sitagliptin and metformin combination therapy has become an essential strategy in combating diabetes. The use of combination therapy such as sitagliptin and metformin in achieving the desired level of glycemia in patients with diabetes is very important and is an additional armamentarium in the fight against diabetes. AREAS COVERED: This article reviews the history of incretins, the pathophysiology of diabetes and the use of sitagliptin and metformin combination therapy. EXPERT OPINION: Achieving optimum blood glucose control is crucial in avoiding or at least delaying the progression of complications related to diabetes. Recently, it has become very clear that treatment with a single antidiabetic agent is often not successful in achieving glycemic control. Thus, many patients with type 2 diabetes require multiple combinations. Using sitagliptin and metformin combination therapy is an ideal strategy in the treatment of diabetes.     

Factors Affecting Contraceptive Use in Ethiopian: A Generalized Linear Mixed Effect Model

BackgroundEthiopia is the second most populous nations in Africa. Family planning is a viable solution to control such fast-growing population. This study aimed to assess the prevalence of contraceptive use and its predictors in Ethiopia.MethodsAbout 4,563 women were drawn randomly by Central Statistics Agency from its master sampling frame. The survey was conducted from January, 2014 to March, 2016 within six months'' interval for the study period. The study was conducted using secondary data collected by PMA2020/Ethiopia project. Negative Binomial regression model was employed for data analysis. The model was selected using information criterion.ResultsPredictors like easy access of health service, residence area, level of health institutions, regions, availability of community health volunteers, experience sharing, support from husbands, level of education and employment status of women as well as residence area significantly affected the performance of contraceptive use in Ethiopia. From the interaction effects of health centers with region and health post with number of opening days per a week were significant predictors of the contraceptive use.ConclusionThe performance of contraceptive use was different from one individual to another because of their experience sharing, support from their husbands, employment status and education level. A woman who got encouragement to use birth control from her husband had good performance to be effective for her contraceptive use. There should be an experience sharing/orientation, about use of birth control to protect women from unwanted pregnancy. Hence, rural women should get experience from urban women.     

Lipid and lipoprotein profiles in Ethiopian patients with diabetes mellitus

The association between dyslipidemia and diabetes mellitus is well established. Although various lipoprotein abnormalities have been described in patients with diabetes mellitus elsewhere, there is limited information from African patients. We undertook a cross-sectional study to assess the prevalence of dyslipidemia in Ethiopian patients with types 1 and 2 diabetes. A total of 193 subjects were included in the study (54 patients had type 1 diabetes mellitus, 92 patients had type 2 diabetes mellitus, and 47 were nondiabetic controls). Of these, 93 (48.6%) were men and 103 (51.4%) were women. The mean age+/-SEM for patients with type 1 diabetes mellitus, type 2 diabetes mellitus, and controls were 29.8+/-1.4, 51.2+/-1.1, and 29.0+/-1.7 years, respectively. Hypercholesterolemia and hypertriglyceridemia, defined as cholesterol level of greater than 5.2 mmol/L and triglyceride level of greater than 1.8 mmol/L, were found in 47.3% and 41.8% of patients with diabetes mellitus compared with 27% and 17% in controls (P<.05 for both). The mean total cholesterol level+/-SEM was significantly higher in patients with type 1 or 2 diabetes mellitus than controls (5.76+/-0.27 mmol/L in type 1 diabetes mellitus, 5.25+/-0.2 mmol/L in type 2 diabetes mellitus, and 4.67+/-0.28 mmol/L in healthy controls, P<.02). Triglycerides and low-density lipoprotein levels were also significantly higher in patients with diabetes than in controls, whereas high-density lipoprotein levels were significantly lower in patients with diabetes. In conclusion, our study demonstrates that in Ethiopians with diabetes mellitus, dyslipidemia occurs more frequently than in controls. Thus, we recommend periodic screening for dyslipidemia in all Ethiopian patients with diabetes. Other studies are needed to assess the potential negative effect of dyslipidemia and obesity on morbidity and mortality in Ethiopians with diabetes.     

Organotypic human oral tissue models for toxicological studies.

Three-dimensional models of the human oral epithelia have been developed to test the irritation of oral-care products and to provide systems to study the pathology of the oral cavity. The in vitro tissue models, cultured using normal oral epithelial cells and serum free medium, adopt a buccal or gingival phenotype. The buccal tissue (designated ORL-200) is 8-12 cell layers thick and non-cornified; the gingival tissue (designated GIN-100) is 9-13 layers thick and cornified at the apical surface. The tissues express cytokeratins 13 and 14 similar to their corresponding native oral tissues. The MTT viability assay was used to assess inter-lot and intra-lot reproducibility. The MTT average intra-lot coefficient of variation (CV) was less than 10% for both tissues and the time required to reduce tissue viability by 50% (ET-50) following application of 1% Triton-X 100 averaged 1.02+/-0.33 h (n=26) and 7.97+/-0.80 h (n=14) for the buccal and gingival tissues, respectively. The utility of the buccal tissue for irritation studies was examined by testing prototype dentifrice formulations and commercially available products including mouthwashes, toothpastes, and oral cleansers. Use of the MTT ET-50 assay and cytokine release clearly differentiated between the formulations and the oral care products. In conclusion, the oral tissue models represent highly reproducible, non-animal means to screen the irritation potential of newly developed oral care products and should be useful to study the innate immunity, biology, and pathology of the oral mucosa.     

Total Mesorectal Excision for Rectal Cancer: Difference in Outcome for Low and High Rectal Cancer

PURPOSE This prospective study was designed to assess the outcome through the first five years after the introduction of total mesorectal excision in 1993 in a Norwegian central hospital, with special regard to the difference between low (≤6 cm from anal verge) and high (>6 cm) rectal cancers. METHODS A total of 140 patients (81 males; median age, 64 (range, 29–87) years) underwent surgery for rectal cancer under curative intention. RESULTS Local recurrence rates were 8 of 44 (18 percent) for the low cancers and 5 of 96 (5 percent) for the high, a statistically significant difference (P = 0.0014). Corresponding numbers when the R1 resections are excluded were 5 of 36 (13 percent) for the low and 4 of 92 (4 percent) for the high cancers (P = 0.002). The five-year survival after R0 resections of cancers <6 cm was significantly reduced compared with those >6 cm. The five-year overall survival for the whole material was 72 percent. CONCLUSIONS Surgery alone for rectal cancer can achieve overall good results, with five-year overall survival of 72 percent. The prognosis of the cancers of the lower rectum seems to be inherently different from the tumors of the higher level, both concerning local recurrence and five-year survival, suggesting different biologic behavior of the two cancers. Presented at the meeting of the Norwegian Surgical Society, Oslo, Norway, October 18 to 22, 2004.     

Organotypic human vaginal-ectocervical tissue model for irritation studies of spermicides, microbicides, and feminine-care products.

A three-dimensional organotypic vaginal-ectocervical (VEC) tissue model has been developed to test the irritation of topically applied spermicides, microbicides, and vaginal-care products. The in vitro tissue model was reconstructed using normal VEC epithelial cells and is well stratified, containing differentiated basal, suprabasal, intermediate, and superficial cell layers similar to in vivo tissue. The intermediate and superficial cell layers contain glycogen, and the expression of cytokeratins 13 and 14 in the tissue also parallels that of native tissue. The MTT viability assay and histological assessment were used to test inter-lot and intra-lot reproducibility. The MTT average intra-lot coefficient of variation (CV) was less than 10% and the time required to reduce tissue viability by 50% (ET-50) following application of 1% Triton X-100 averaged 1.25+/-0.24h (n=23) upon completion of the 11-day culture period and 1.30 h+/- 0.19 for the same tissues stored overnight at 4 degrees C on agarose gels. The utility of the VEC model for irritation studies was examined by testing commercially available products using the MTT assay and histological assessment. The average ET-50 values ranged between 1.8 and 2.7h for feminine washes, 3.9-6.7 h for spermicides, 6.8-18 h for anti-itch creams, and >18 h for douches, lubricants, and anti-fungal creams. Studies of cytokines released from VEC cultures following product application showed that elevated concentrations of IL-1alpha and IL-1beta were associated with toxicity of test materials. In conclusion, the VEC tissue model is a highly reproducible, non-animal means to assess the irritation of contraceptives, microbicides, and vaginal-care products.