Effect of the α-glucosidase inhibitor miglitol on the glucose profile in Japanese type 2 diabetic patients receiving multiple daily insulin injections.

Strict postprandial glycemic control may have a preventive effect on atherogenesis in patients with type 2 diabetes. The α-glucosidase inhibitor (α-GI) miglitol is useful for controlling the early postprandial increase of glucose, but the combined effect of miglitol and multiple daily insulin injections (MDI) on glucose excursion has not been evaluated. First, we retrospectively compared the daily glucose profile, evaluated by self-monitoring of blood glucose (SMBG) at nine times on the day before discharge from hospital, between type 2 diabetic patients receiving MDI (n=81) or MDI plus miglitol at 150 mg daily (n=24). Second, we prospectively examined the effect of adding miglitol to MDI on the daily glucose profile (SMBG) in 19 other type 2 diabetic patients. Although the daily insulin dosage and the glucose level before meals did not differ between the two groups, the 1-h postprandial glucose level after each meal, 2-h glucose level after lunch and dinner, mean and standard deviation of glucose, and amplitude of glucose excursion were significantly lower or smaller in the MDI plus miglitol group than in the MDI group. All of these glucose parameters were significantly improved by adding miglitol to MDI in the prospective cohort of 19 patients. In conclusion, adding miglitol to MDI reduces postprandial glucose levels and attenuates daily glucose fluctuation in type 2 diabetic patients. This trial was registered with UMIN (no. UMIN000005383).

Efficacy of low-dose rosuvastatin in patients with type 2 diabetes and hypo high-density lipoprotein cholesterolaemia.

OBJECTIVE: To analyse the efficacy of low-dose rosuvastatin for treating hypo high-density lipoprotein (HDL) cholesterolaemia in patients with type 2 diabetes and dyslipidaemia. METHODS: Patients with HDL-cholesterol (C) < 40 mg/dl and triglycerides (TG) < 400 mg/dl who were receiving treatment with lipid-lowering drugs other than rosuvastatin (or previously untreated with lipid-lowering drugs) and with low-density lipoprotein [LDL]-C ≥ 120 mg/dl were included. Patients were treated with 2.5 or 5 mg rosuvastatin orally, once daily, to achieve the target LDL-C level specified in Japanese guidelines. Changes in total cholesterol, HDL-C, TG, LDL-C, LDL-C/HDL-C and non-HDL-C at 3 and 6 months were prospectively analysed. Safety was evaluated by examining changes in hepatorenal function, glucose metabolism and creatine kinase. RESULTS: Out of 49 patients, all lipid parameters other than TG were significantly improved at 3 and 6 months. At 3 months, 83.3% of patients had achieved the target LDL-C level. Among nonlipid parameters, no changes were observed except for estimated glomerular filtration rate, which was improved by + 5.2% and + 9.6% at 3 and 6 months, respectively. CONCLUSIONS: Low-dose rosuvastatin was effective in improving hypo-HDL cholesterolaemia and may have renoprotective effects.

Real time ligand-induced motion mappings of AChBP and nAChR using X-ray single molecule tracking.

We observed the dynamic three-dimensional (3D) single molecule behaviour of acetylcholine-binding protein (AChBP) and nicotinic acetylcholine receptor (nAChR) using a single molecule tracking technique, diffracted X-ray tracking (DXT) with atomic scale and 100 µs time resolution. We found that the combined tilting and twisting motions of the proteins were enhanced upon acetylcholine (ACh) binding. We present the internal motion maps of AChBP and nAChR in the presence of either ACh or α-bungarotoxin (αBtx), with views from two rotational axes. Our findings indicate that specific motion patterns represented as biaxial angular motion maps are associated with channel function in real time and on an atomic scale.

Directed evolution of a three-finger neurotoxin by using cDNA display yields antagonists as well as agonists of interleukin-6 receptor signaling.

BACKGROUND: Directed evolution of biomolecules such as DNA, RNA and proteins containing high diversity has emerged as an effective method to obtain molecules for various purposes. In the recent past, proteins from non-immunoglobulins have attracted attention as they mimic antibodies with respect to binding potential and provide further potential advantages. In this regard, we have attempted to explore a three-finger neurotoxin protein (3F). 3F proteins are small (~7 kDa), structurally well defined, thermally stable and resistant to proteolysis that presents them as promising candidates for directed evolution. RESULTS: We have engineered a snake α-neurotoxin that belongs to the 3F family by randomizing the residues in the loops involved in binding with acetylcholine receptors and employing cDNA display to obtain modulators of interleukin-6 receptor (IL-6R). Selected candidates were highly specific for IL-6R with dissociation constants and IC50s in the nanomolar range. Antagonists as well as agonists were identified in an IL-6 dependent cell proliferation assay. Size minimization yielded peptides of about one-third the molecular mass of the original proteins, without significant loss of activities and, additionally, lead to the identification of the loops responsible for function. CONCLUSIONS: This study shows 3F protein is amenable to introduce amino acid changes in the loops that enable preparation of a high diversity library that can be utilized to obtain ligands against macromolecules. We believe this is the first report of protein engineering to convert a neurotoxin to receptor ligands other than the parent receptor, the identification of an agonist from non-immunoglobulin proteins, the construction of peptide mimic of IL-6, and the successful size reduction of a single-chain protein.

Malachite green-conjugated microtubules as mobile bioprobes selective for malachite green aptamers with capturing/releasing ability.

We have developed a novel mobile bioprobe using a conjugate of a kinesin-driven microtubule (MT) and malachite green (MG) as a platform for capturing MG RNA aptamers. The fluorescence of MG increases when it is bound to an MG aptamer, allowing MT-MG conjugates to work as sensors of RNA transcripts containing the MG aptamer sequence. Kinesin motor proteins provide an effective driving force to create mobile bioprobes without any manipulation. Although the fluorescence of a small number of MG-binding aptamers is low, the self-organization of tubulins into MTs enables the microscopic observation of the bound aptamers by collecting them on MTs. We demonstrate that MT-MG conjugates can select target aptamers from a transcription mixture and transport them without losing their inherent motility. Because the MG aptamer binds MG in a reversible manner, MT-MG conjugates can conditionally load and unload the target aptamers. This is one advantage of this system over the molecular probes developed previously in which reversible unloading is impossible due to high-affinity binding, such as between avidin and biotin. Furthermore, an MT-MG conjugate can be used as a platform for other MG aptameric sensors with recognition regions for various target analytes optimized by further selection procedures. This is the first step to applying living systems to in vitro devices. This technique could provide a new paradigm of mobile bioprobes establishing high-throughput in vitro selection systems using microfluidic devices operating in parallel.