sodium-dodecyl-sulfate and Diabetes-Mellitus--Type-2

Myeloid cells are key regulators of tissue homeostasis and disease. Alterations in cell-autonomous insulin/IGF-1 signaling in myeloid cells have recently been implicated in the development of systemic inflammation and insulin-resistant diabetes mellitus type 2 (DM). Impaired wound healing and inflammatory skin diseases are frequent DM-associated skin pathologies, yet the underlying mechanisms are elusive. In this study, we investigated whether myeloid cell-restricted IR/IGF-1R signaling provides a pathophysiologic link between systemic insulin resistance and the development of cutaneous inflammation. Therefore, we generated mice lacking both the insulin and IGF-1 receptor in myeloid cells (IR/IGF-1R(MKO)). Whereas the kinetics of wound closure following acute skin injury was similar in control and IR/IGF-1R(MKO) mice, in two different conditions of dermatitis either induced by repetitive topical applications of the detergent SDS or by high-dose UV B radiation, IR/IGF-1R(MKO) mice were protected from inflammation, whereas controls developed severe skin dermatitis. Notably, whereas during the early phase in both inflammatory conditions the induction of epidermal proinflammatory cytokine expression was similar in control and IR/IGF-1R(MKO) mice, during the late stage, epidermal cytokine expression was sustained in controls but virtually abrogated in IR/IGF-1R(MKO) mice. This distinct kinetic of epidermal cytokine expression was paralleled by proinflammatory macrophage activation in controls and a noninflammatory phenotype in mutants. Collectively, our findings provide evidence for a proinflammatory IR/IGF-1R-dependent pathway in myeloid cells that plays a critical role in the dynamics of an epidermal-dermal cross-talk in cutaneous inflammatory responses, and may add to the mechanistic understanding of diseases associated with disturbances in myeloid cell IR/IGF-1R signaling, including DM.

Topics: Animals; Cells, Cultured; Cytokines; Dermatitis; Diabetes Mellitus, Type 2; Inflammation; Insulin Resistance; Macrophage Activation; Macrophages; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Receptor, IGF Type 1; Receptor, Insulin; Signal Transduction; Skin; Sodium Dodecyl Sulfate; Ultraviolet Rays

The poorly water soluble antidiabetic drug gliclazide was selected to study the effect of excipients on dissolution rate enhancement. Ordered mixtures of micronized gliclazide with lactose, mannitol, sorbitol, maltitol and sodium chloride were prepared by manual shaking of glass vials containing the drug and excipient(s). Different water soluble excipients, addition of surfactant and superdisintegrant, drug concentration and carrier particle size influenced the dissolution rate of the drug. Dissolution rate studies of the prepared ordered mixtures revealed an increase in drug dissolution with all water soluble excipients. The order of dissolution rate improvement for gliclazide was mannitol > lactose > maltitol > sorbitol > sodium chloride. Composite granules of the particle size range 355-710 μm were superior in increasing the drug dissolution rate from ordered mixtures. Reducing the carrier particle size decreased the dissolution rate of the drug as well as the increase in drug concentration. Kinetic modeling of drug release data fitted best the Hixson-Crowell model, which indicates that all the ordered mixture formulations followed the cube root law fairly well.

Topics: Diabetes Mellitus, Type 2; Drug Carriers; Drug Compounding; Drug Delivery Systems; Excipients; Gliclazide; Humans; Hypoglycemic Agents; Lactose; Maltose; Models, Theoretical; Particle Size; Pharmacokinetics; Sodium Dodecyl Sulfate; Solubility; Starch; Sugar Alcohols; Surface-Active Agents; Suspensions; Water

Amylin is an endocrine hormone that regulates metabolism. In patients afflicted with type 2 diabetes, amylin is found in fibrillar deposits in the pancreas. Membranes are thought to facilitate the aggregation of amylin, and membrane-bound oligomers may be responsible for the islet beta-cell toxicity that develops during type 2 diabetes. To better understand the structural basis for the interactions between amylin and membranes, we determined the NMR structure of human amylin bound to SDS micelles. The first four residues in the structure are constrained to form a hairpin loop by the single disulfide bond in amylin. The last nine residues near the C terminus are unfolded. The core of the structure is an alpha-helix that runs from about residues 5-28. A distortion or kink near residues 18-22 introduces pliancy in the angle between the N- and C-terminal segments of the alpha-helix. Mobility, as determined by (15)N relaxation experiments, increases from the N to the C terminus and is strongly correlated with the accessibility of the polypeptide to spin probes in the solution phase. The spin probe data suggest that the segment between residues 5 and 17 is positioned within the hydrophobic lipid environment, whereas the amyloidogenic segment between residues 20 and 29 is at the interface between the lipid and solvent. This orientation may direct the aggregation of amylin on membranes, whereas coupling between the two segments may mediate the transition to a toxic structure.

Topics: Amyloid; Cell Membrane; Diabetes Mellitus, Type 2; Humans; Insulin-Secreting Cells; Islet Amyloid Polypeptide; Micelles; Models, Molecular; Nuclear Magnetic Resonance, Biomolecular; Protein Binding; Protein Structure, Secondary; Sodium Dodecyl Sulfate

The emerging new fixed dose combination of metformin hydrocholride (HCl) as sustained release and glipizide as immediate release were formulated as a bilayer matrix tablet using hydroxy propyl methyl cellulose (HPMC) as the matrix-forming polymer, and the tablets were evaluated via in vitro studies. Three different grades of HPMC (HPMC K 4M, HPMC K 15M, and HPMC K 100M) were used. All tablet formulations yielded quality matrix preparations with satisfactory tableting properties. In vitro release studies were carried out at a phosphate buffer of pH 6.8 with 0.75% sodium lauryl sulphate w/v using the apparatus I (basket) as described in the United States Pharmacopeia (2000). The release kinetics of metformin were evaluated using the regression coefficient analysis. There was no significant difference in drug release for different viscosity grade of HPMC with the same concentration. Tablet thus formulated provided sustained release of metformin HCl over a period of 8 hours and glipizide as immediate release.

Topics: Chemistry, Pharmaceutical; Delayed-Action Preparations; Diabetes Mellitus, Type 2; Drug Combinations; Excipients; Glipizide; Hypoglycemic Agents; Hypromellose Derivatives; Metformin; Methylcellulose; Sodium Dodecyl Sulfate; Tablets; Technology, Pharmaceutical; Viscosity

Polymorphism in the angiotensin-converting enzyme (ACE) gene has been shown to correlate with circulating ACE concentrations in plasma, and also to be an independent risk factor in the development of many cardiovascular diseases. However, methods available today for ACE genotyping are still laborious and time-consuming. Here we report a sensitive, simple and non-isotopic procedure with commercially available gels for the identification of ACE insertion/ deletion polymorphism. This technique includes rapid extraction of the DNA by the QIAamp Blood Kit prior to polymerase chain reaction, followed by sodium dodecylsulphate polyacrylamide gel electrophoresis using the PhastSystem (Pharmacia). The procedure can be accomplished in five-hours from drawing the blood samples to the final result.

Topics: Aged; Alleles; Diabetes Mellitus, Type 2; DNA; Electrophoresis, Polyacrylamide Gel; Genotype; Humans; Middle Aged; Peptidyl-Dipeptidase A; Polymerase Chain Reaction; Polymorphism, Genetic; Sensitivity and Specificity; Silver Staining; Sodium Dodecyl Sulfate; Time Factors

Silent myocardial ischemia in non-insulin-dependent diabetic patients occurs frequently in association with autonomic dysfunction, suggesting that diabetic neuropathy may be involved in the development of this disorder. Repeated episodes of silent myocardial ischemia can induce myocardial necrosis. Recently, actin was detected with Western blotting in the serum of patients with acute myocardial infarction and angina pectoris. We found that a large proportion of non-insulin-dependent diabetic patients with neuropathy also have detectable circulating concentrations of alpha-actin, and therefore suggest that the determination by immunoblotting of serum alpha-actin in such patients is an effective method to detect myocardial cell suffering and to identify patients that may need special consideration.

Topics: Actins; Angina Pectoris; Autonomic Nervous System Diseases; Blotting, Western; Diabetes Mellitus, Type 2; Diabetic Neuropathies; Electrophoresis, Polyacrylamide Gel; Female; Heart Rate; Humans; Immunoblotting; Male; Middle Aged; Myocardial Infarction; Myocardial Ischemia; Sodium Dodecyl Sulfate

The aim of the present study was to characterize the eventual presence and molecular forms of gelatinase/type IV collagenase activities in gingival crevicular fluid (GCF) and saliva in different forms of periodontitis; patients with clinically healthy periodontium served as controls. Enzyme activities were monitored electrophoretically by zymography using gelatin and type IV collagen as substrates and analyzed visually and/or densitometrically. Both saliva and GCF collected from adult periodontitis, localized juvenile periodontitis and type II diabetes mellitus periodontitis patients contained species moving identically with gelatinase isolated from human neutrophils or MMP-9 (mean 98 kD), and species with mobility similar to gelatinase in fibroblast cell culture supernatants or MMP-2 (mean 76 kD). Hitherto, undescribed high molecular weight forms (mean 128 kD), were found, possibly representing polymerized or complexed enzyme active/activated in situ in the gel matrix. Small molecular forms of gelatinases (mean 51 kD and 46 kD), unable to cleave type IV collagen, were also found, most likely representing in vivo proteolytically activated, truncated enzymes. Although multiple forms of gelatinases/type IV collagenases in saliva and GCF may take part in the tissue destruction in periodontitis, their profile judged according to molecular weights does not differentiate between different forms of periodontitis.

Topics: Adult; Aggressive Periodontitis; Collagenases; Diabetes Mellitus, Type 2; Electrophoresis, Polyacrylamide Gel; Female; Gelatinases; Gingival Crevicular Fluid; Humans; Male; Matrix Metalloproteinase 9; Middle Aged; Molecular Weight; Periodontal Pocket; Periodontitis; Periodontium; Saliva; Sodium Dodecyl Sulfate

Topics: Diabetes Mellitus, Type 2; Diabetic Nephropathies; Electrophoresis, Polyacrylamide Gel; Female; Humans; Male; Middle Aged; Proteinuria; Sodium Dodecyl Sulfate; Urinary Tract Infections