New Measurement of the π0 radiative decay width

High precision measurements of the differential cross sections for π0 photoproduction at forward angles for two nuclei, 12C and 208Pb, have been performed for incident photon energies of 4.9-5.5 GeV to extract the π0→γγ decay width. The experiment was done at Jefferson Lab using the Hall B photon tagger and a high-resolution multichannel calorimeter. The π0→γγ decay width was extracted by fitting the measured cross sections using recently updated theoretical models for the process. The resulting value for the decay width is Γ(π0→γγ)=7.82±0.14(stat)±0.17(syst)  eV. With the 2.8% total uncertainty, this result is a factor of 2.5 more precise than the current Particle Data Group average of this fundamental quantity, and it is consistent with current theoretical predictions.

Fabrication of porous beta-tricalcium phosphate with microchannel and customized geometry based on gel-casting and rapid prototyping

The tissue engineering scaffolds with three-dimensional porous structure are regarded to be beneficial to facilitate a sufficient supply of nutrients and enable cell ingrowth in bone reconstruction. However, the pores in scaffolds tend to be blocked by the cell ingrowth and result in a restraint of nutrient supply in the further side of the scaffold. An indirect approach of combining the rapid prototyping and gel-casting technique is introduced in this study to fabricate beta-tricalcium phosphate (beta-TCP) scaffolds which not only have interconnected porous structure, but also have a microchannel network inside. The scaffold was designed with customized geometry that matches the defect area, and a double-scale (micropores-microchannel) porous structure inside that is beneficial for cell ingrowth. The scaffolds fabricated have an open, uniform, and interconnected porous architecture with a pore size of 200-400 microm, and posses an internal channel network with a diameter of 600 microm. The porosity was controllable. The compressive yield strength was 4.5 MPa with a porosity of 70 per cent. X-ray diffraction analysis shows that these fabrication processes do not change the crystal structure and chemical composition of beta-TCP. With this technique, it was also possible to fabricate porous scaffolds with desired pore size, porosity, and microchannel, as well as customized geometries by other bioceramics.

Alterations of collagen-I, MMP-1 and TIMP-1 in the periodontal ligament of diabetic rats under mechanical stress

BACKGROUND AND OBJECTIVE

The present study assessed effects of hyperglycemia on production of proteins involved in remodeling of the periodontal ligament under mechanical stress.

MATERIAL AND METHODS

Forty-eight Sprague-Dawley rats were randomly divided into the following two groups: nondiabetic (ND) and diabetes induced (DI; n=24 each group). Diabetes was induced in the DI group by a single dose of streptozotocin, and saline solution was injected in the ND group. Rats were killed 1-14d after induction of mechanical pressure (50g) on the first upper left molar. Alterations of collagen type I (Col-I), MMP-1 and TIMP-1 in the upper left periodontal ligament of these rats were measured immunohistochemically and compared with those on the contralateral side of the same rat (control; no force induction).

RESULTS

The DI group showed a decrease in Col-I and an increase in MMP-1 compared with the ND group. Both Col-I and MMP-1 increased in both groups, whereas TIMP-1 was decreased following mechanical pressure. The DI group exhibited a longer duration of increased MMP-1 and MMP/TIMP ratio compared with the ND group.

CONCLUSION

Diabetes affects proteins involved in remodeling of periodontal ligament during mechanical pressure. This may delay the reconstruction and remodeling of periodontal ligament in diabetic individuals.

Proteome analysis of differential protein expression in brain of rats with type 1 diabetes mellitus

AIM OF THE STUDY

Proteomic approach was applied to identify differential protein expressed in brain of rats with type 1 diabetes mellitus (T1DM) in order to search for potential biomarkers for pathological changes of brain with T1DM.

METHODS

Proteins were extracted from brain tissues of T1DM rats and healthy control rats, separated by 2-DE and identified by MALDI-TOF-MS. The results were validated by Western blot analysis and immunohistochemistry (IHC).

RESULTS

A total of 8 proteins from the 24 differentially expressed spots were identified by MALDI-TOF-MS. The proteins identified were vitamin D-dependent calcium-binding protein, creatine kinase B-type (B-CK), myosin light chain kinase (MLCK), HSP60 and HSP71, ATP synthase, cyclin-G, pantothenate kinase-1 (PANK1), respectively. 3 proteins were up-regulated and 5 proteins were down-regulated from the T1DM rats. Of the 8 proteins identified, MLCK was confirmed by Western blot and IHC.

CONCLUSION

This work demonstrates that a comprehensive strategy of proteomic identification should be a useful tool for understanding of diabetic encephalopathy mechanism. And the differential proteins such as MLCK may be give clues about the pathogenesis of diabetic encephalopathy.

Effects of Metformin and Rosiglitazone on Peripheral Insulin Resistance and β-Cell Function in Obesity: A Double-Blind, Randomized, Controlled Study

Metformin and rosiglitazone combination therapy is known to improve insulin resistance and postpone diabetes mellitus development in subjects with impaired glucose tolerance. This double-blind, randomized, controlled study assessed this combination therapy for preventing type 2 diabetes in obese subjects with hyperinsulinaemia. Subjects received metformin (500 mg three times daily, orally) plus either rosiglitazone (4 mg once daily, orally; n = 94) or placebo ( n = 95) and were followed for 6 months. Blood pressure, body fat, body mass index (BMI), lipid and insulin levels were recorded pre-and post-treatment. Metformin plus rosiglitazone significantly decreased blood pressure, lipids, BMI, and fasting and postmeal insulin levels. Metformin plus placebo led to a significant decrease in blood pressure, BMI and lipid levels, but fasting and postmeal insulin levels were unchanged. Adverse events were similar between the two groups. The metformin and rosiglitazone combination increased insulin sensitivity and β-cell function recovered. This approach may represent a therapeutic option for preventing development of type 2 diabetes in obese subjects with hyperinsulinaemia.

Effects of Shade Intensity and Duration on Asian Soybean Rust Caused by Phakopsora pachyrhizi

Field studies to quantify the effects of shade intensity and duration on soybean rust caused by Phakopsora pachyrhizi were carried out in Florida in 2006 and 2007. Soybean plants at the V4 stage were inoculated with urediniospores at 2100, 0000, and 0200 h. Inoculated plants were either placed in cages that were covered with shade cloths of different mesh sizes allowing 70, 50, or 20% transmission of sunlight or were not covered so that the plants received 100% of sunlight. Plants kept under 20 and 100% sunlight were sampled 12, 18, and 36 h after inoculation to determine the in vivo germination percentage of urediniospores and the percentage of germ tubes that formed appressoria. In separate experiments, inoculated plants were placed under the shade (20% sunlight) and moved to unshaded conditions after 1, 2, and 7 days. For all experiments, soybean rust incidence and severity were rated 12 days after inoculation. Higher levels of disease incidence and severity were detected in plants under shade compared with those under full sunlight. Shade duration greater than 2 days favored disease development. Within 36 h, in vivo germination of urediniospores and formation of appressoria were not significantly affected by the treatments. These results may explain why soybean rust is more severe in the lower canopy and shaded areas in the field.

Effect of 70-nm silica particles on the toxicity of acetaminophen, tetracycline, trazodone, and 5-aminosalicylic acid in mice

Exposure to nano-sized particles is increasing because they are used in a wide variety of industrial products, cosmetics, and pharmaceuticals. Some animal studies indicate that such nanomaterials may have some toxicity, but their synergistic actions on the adverse effects of drugs are not well understood. In this study, we investigated whether 70-nm silica particles (nSP70), which are widely used in cosmetics and drug delivery, affect the toxicity of a drug for inflammatory bowel disease (5-aminosalicylic acid), an antibiotic drug (tetracycline), an antidepressant drug (trazodone), and an antipyretic drug (acetaminophen) in mice. Co-administration of nSP70 with trazodone did not increase a biochemical marker of liver injury. In contrast, co-administration increased the hepatotoxicity of the other drugs. Co-administration of nSP70 and tetracycline was lethal. These findings indicate that evaluation of synergistic adverse effects is important for the application of nano-sized materials.