A systematic comparison of protocols for recovery of high-quality rna from human islets extracted by laser capture microdissection

The isolation of high-quality RNA from endocrine pancreas sections represents a consider-able challenge largely due to the high ribonuclease levels. Laser capture microdissection (LCM) of mammalian islets, in association with RNA extraction protocols, has emerged as a feasible approach to characterizing their genetic and proteomic profiles. However, a validated protocol to obtain high-quality RNA from LCM-derived human pancreas specimens that is appropriate for next-generation sequencing analysis is still lacking. In this study, we applied four methods (Picopure extraction kit, Qiazol protocol, Qiazol + Clean-up kit, and RNeasy Microkit + Carrier) to extract RNA from human islets obtained from both non-diabetic individuals and patients with type 2 diabetes who had undergone partial pancreatectomy, as well as handpicked islets from both non-diabetic and diabetic organ donors. The yield and purity of total RNA were determined by 260/280 absorbance using Nanodrop 100 and the RNA integrity number with a bioanalyzer. The results indicated that among the four methods, the RNeasy MicroKit + Carrier (Qiagen) provides the highest yield and purity

Vitamin D deficiency: A new risk factor for type 2 diabetes?

Recent compelling evidence suggests a role of vitamin D deficiency in the pathogenesis of insulin resistance and insulin secretion derangements, with a consequent possible interference with type 2 diabetes mellitus. The mechanism of this link is incompletely understood. In fact, vitamin D deficiency is usually detected in obesity in which insulin resistance is also a common finding. The coexistence of insulin resistance and vitamin D deficiency has generated several hypotheses. Some cross-sectional and prospective studies have suggested that vitamin D deficiency may play a role in worsening insulin resistance; others have identified obesity as a risk factor predisposing individuals to exhibit both vitamin D deficiency and insulin resistance. The available data from intervention studies are largely confounded, and inadequate considerations of seasonal effects on 25(OH)D concentrations are also a common design flaw in many studies. On the contrary, there is strong evidence that obesity might cause both vitamin D deficiency and insulin resistance, leaving open the possibility that vitamin D and diabetes are not related at all. Although it might seem premature to draw firm conclusions on the role of vitamin D supplementation in reducing insulin resistance and preventing type 2 diabetes, this manuscript will review the circumstances leading to vitamin D deficiency and how such a deficiency can eventually independently affect insulin sensitivity. © 2012 S. Karger AG, Basel

ANALISIS PELAKSANAAN PRAKTIKUM DAN PERMASALAHANNYA MATERI ORGANISASI KEHIDUPAN SMP KECAMATAN TANJUNGKARANG PUSAT

This study aims to analyze practicum implementation and problems about living organism of VII grade teachers on Junior High School in Tanjungkarang Pusat year 2016/2017. The sample were VII grade Sains teachers who carried out practicum of living organism that were selected by purposive sampling. Exploratory research design was used in this research. Research data were obtained from questionnaires, interviews and observations that were analyzed descriptively. The result showed that teacher's and students response to the practicum implementation, the phases of practicum, and the student worksheets by teachers had score that were 75.21%, 76.10%, 69.91%, and 49.73%. Thus, the practicum implementation by teachers and students was good, the phases of practicum have good criteria, and student worksheets by teachers were quite good. The problems in practical activities are limited; (1) laboratory facilities, (2) number of microscopes, and (3) number of animal and plant cells.Penelitian ini bertujuan menganalisis pelaksanaan praktikum dan permasalahannya pada materi organisasi kehidupan di SMP kelas VII Kecamatan Tanjungkarang Pusat tahun pelajaran 2016/2017. Sampel penelitian dipilih menggunakan teknik purposive sampling yaitu guru IPA kelas VII yang melaksanakan praktikum materi organisasi kehidupan. Desain penelitian yang digunakan yaitu desain riset eksploratori. Data penelitian diperoleh dari angket, wawancara, dan observasi kemudian dianalisis secara deskriptif. Hasil penelitian menunjukkan tanggapan guru dan tanggapan siswa terhadap pelaksanaan praktikum, tahapan pelaksanaan praktikum, serta LKS-praktikum yang disusun guru berturut-turut memperoleh skor 75,21%, 76,10%, 69,91%, dan 49,73%. Dengan demikian pelaksanaan praktikum oleh guru dan siswa berkriteria baik, tahapan pelaksanaan praktikum berkriteria baik, dan LKS-praktikum yang disusun guru berkriteria cukup baik. Permasalahan yang muncul dalam kegiatan praktikum yaitu keterbatasan; (1) sarana laboratorium, (2) jumlah mikroskop cahaya, dan (3) jumlah preparat awetan sel hewan dan tumbuhan.Kata kunci: organisasi kehidupan, pelaksanaan praktikum, permasalahan praktiku

Insulin regulates arginine-stimulated insulin secretion in humans

Aims: Insulin potentiates glucose-stimulated insulin secretion. These effects are attenuated in beta cell–specific insulin receptor knockout mice and insulin resistant humans. This investigation examines whether short duration insulin exposure regulates beta cell responsiveness to arginine, a non-glucose secretagogue, in healthy humans. Materials and methods: Arginine-stimulated insulin secretion was studied in 10 healthy humans. In each subject arginine was administered as a bolus followed by continuous infusion on two occasions one month apart, after sham/saline or hyperinsulinemic-isoglycemic clamp, respectively providing low and high insulin pre-exposure conditions. Arginine-stimulated insulin secretion was measured by C-peptide deconvolution, and by a selective immunogenic (DAKO) assay for direct measurement of endogenous but not exogenous insulin. Results: Pre-exposure to exogenous insulin augmented arginine-stimulated insulin secretion. The effect was seen acutely following arginine bolus (endogenous DAKO insulin incremental AUC240-255min 311.6 ± 208.1 (post-insulin exposure) versus 120.6 ± 42.2 μU/ml•min (sham/saline) (t-test P = 0.021)), as well as in response to continuous arginine infusion (DAKO insulin incremental AUC260-290min 1095.3 ± 592.1 (sham/saline) versus 564.8 ± 207.1 μU/ml•min (high insulin)(P = 0.009)). Findings were similar when beta cell response was assessed using C-peptide, insulin secretion rates by deconvolution, and the C-peptide to glucose ratio. Conclusions: We demonstrate a physiologic role of insulin in regulation of the beta cell secretory response to arginine

Sotagliflozin, the first dual SGLT inhibitor. Current outlook and perspectives

Sotagliflozin is a dual sodium-glucose co-transporter-2 and 1 (SGLT2/1) inhibitor for the treatment of both type 1 (T1D) and type 2 diabetes (T2D). Sotagliflozin inhibits renal sodium-glucose co-transporter 2 (determining significant excretion of glucose in the urine, in the same way as other, already available SGLT-2 selective inhibitors) and intestinal SGLT-1, delaying glucose absorption and therefore reducing post prandial glucose. Well-designed clinical trials, have shown that sotagliflozin (as monotherapy or add-on therapy to other anti-hyperglycemic agents) improves glycated hemoglobin in adults with T2D, with beneficial effects on bodyweight and blood pressure. Similar results have been obtained in adults with T1D treated with either continuous subcutaneous insulin infusion or multiple daily insulin injections, even after insulin optimization. A still ongoing phase 3 study is currently evaluating the effect of sotagliflozin on cardiovascular outcomes (ClinicalTrials.gov NCT03315143). In this review we illustrate the advantages and disadvantages of dual SGLT 2/1 inhibition, in order to better characterize and investigate its mechanisms of action and potentialities

Insulin resistance alters islet morphology in nondiabetic humans

Type 2 diabetes is characterized by poor glucose uptake in metabolic tissues and manifests when insulin secretion fails to cope with worsening insulin resistance. In addition to its effects on skeletal muscle, liver, and adipose tissue metabolism, it is evident that insulin resistance also affects pancreatic β-Cells. To directly examine the alterations that occur in islet morphology as part of an adaptive mechanism to insulin resistance, we evaluated pancreas samples obtained during pancreatoduodenectomy from nondiabetic subjects who were insulin-resistant or insulin-sensitive. We also compared insulin sensitivity, insulin secretion, and incretin levels between the two groups. We report an increased islet size and an elevated number of band a-cells that resulted in an altered β-Cell-to-a-cell area in the insulin- resistant group. Our data in this series of studies suggest that neogenesis from duct cells and transdifferentiation of a-cells are potential contributors to the β-Cell compensatory response to insulin resistance in the absence of overt diabetes. © 2014 by the American Diabetes Association.

Can vitamin D deficiency cause diabetes and cardiovascular diseases? Present evidence and future perspectives

Several studies have shown that vitamin D may play a role in many biochemical mechanisms in addition to bone and calcium metabolism. Recently, vitamin D has sparked widespread interest because of its involvement in the homeostasis of the cardiovascular system. Hypovitaminosis D has been associated with obesity, related to trapping in adipose tissue due to its lipophilic structure. In addition, vitamin D deficiency is associated with increased risk of cardiovascular disease (CVD) and this may be due to the relationship between low vitamin D levels and obesity, diabetes mellitus, dyslipidaemia, endothelial dysfunction and hypertension. However, although vitamin D has been identified as a potentially important marker of CVD, the mechanisms through which it might modulate cardiovascular risk are not fully understood. Given this background, in this work we summarise clinical retrospective and prospective observational studies linking vitamin D levels with cardio-metabolic risk factors and vascular outcome. Moreover, we review various randomised controlled trials (RCTs) investigating the effects of vitamin D supplementation on surrogate markers of cardiovascular risk. Considering the high prevalence of hypovitaminosis D among patients with high cardiovascular risk, vitamin D replacement therapy in this population may be warranted; however, further RCTs are urgently needed to establish when to begin vitamin D therapy, as well as to determine the dose and route and duration of administration. © 2011 Elsevier B.V

Increased Beta Cell Workload Modulates Proinsulin/Insulin Ratio in Humans

Increased proinsulin secretion, which characterizes type 2 diabetes and insulin resistance, may be due to an intrinsic, primitive defect in proinsulin processing, or be secondary to increased demand on \u3b2-cells (hyperinsulinemia secondary to insulin resistance). An alternative way to investigate the relation between relative hyperproinsulinemia and increased secretory demand is to study the dynamic changes in proinsulin to insulin ratio after partial pancreatectomy, a model of acute increased beta cell workload on the remaining pancreas. To pursue this aim, non-diabetic patients, scheduled for partial pancreatectomy, underwent 4-hour mixed meal tests and hyperinsulinemic euglycemic clamps before and after surgery. Following acute beta cell mass reduction, no changes were observed in fasting proinsulin to insulin ratio, while fold change in proinsulin to insulin ratio significantly increased over time after the meal. Further, our data demonstrate that whole-body insulin resistance is associated with underlying defects in proinsulin secretion, which become detectable only in the presence of increased insulin secretion demand

Effect of Vitamin D Supplementation on Obesity-Induced Insulin Resistance: A Double-Blind, Randomized, Placebo-Controlled Trial

Objective: The aim was to investigate whether vitamin D supplementation, combined with a hypocaloric diet, could have an independent effect on insulin sensitivity in subjects with both overweight and hypovitaminosis D. Changes from baseline in anthropometric parameters, body composition, glucose tolerance, and insulin secretion were considered as secondary outcomes. Methods: Eighteen volunteers who were nondiabetic and vitamin D deficient and had BMI > 25 kg/m2 were randomized (1:1) in a double-blind manner to a hypocaloric diet + either oral cholecalciferol at 25,000 IU/wk or placebo for 3 months. Hyperinsulinemic-euglycemic clamp to measure insulin sensitivity was performed at baseline and after intervention. Results: Body weight in both groups decreased significantly (−7.5% in the vitamin D group and −10% in the placebo group; P < 0.05 for both), with no between-group differences. Serum 25-hydroxyvitamin D levels in the vitamin D group increased considerably (from 36.7 ± 13.2 nmol/L to 74.8 ± 18.7 nmol/L; P < 0.001). Insulin sensitivity in the vitamin D group improved (from 4.6 ± 2.0 to 6.9 ± 3.3 mg·kg−1·min−1; P < 0.001), whereas no changes were observed in the placebo group (from 4.9 ± 1.1 to 5.1 ± 0.3 mg·kg−1·min−1; P = 0.84). Conclusions: Cholecalciferol supplementation, combined with a weight loss program, significantly improves insulin sensitivity in healthy subjects with obesity and might represent a personalized approach for insulin-resistant subjects with obesity