Molecular Biological and Clinical Understanding of the Pathophysiology and Treatments of Hyperuricemia and Its Association with Metabolic Syndrome,Cardiovascular Diseases and Chronic Kidney Disease

Uric acid (UA) is synthesized mainly in the liver, intestines, and vascular endothelium as the end product of an exogenous purine from food and endogenously from damaged, dying, and dead cells. The kidney plays a dominant role in UA excretion, and the kidney excretes approximately 70% of daily produced UA; the remaining 30% of UA is excreted from the intestine. When UA production exceeds UA excretion, hyperuricemia occurs. Hyperuricemia is significantly associated with the development and severity of the metabolic syndrome. The increased urate transporter 1 (URAT1) and glucose transporter 9 (GLUT9) expression, and glycolytic disturbances due to insulin resistance may be associated with the development of hyperuricemia in metabolic syndrome. Hyperuricemia was previously thought to be simply the cause of gout and gouty arthritis. Further, the hyperuricemia observed in patients with renal diseases was considered to be caused by UA underexcretion due to renal failure, and was not considered as an aggressive treatment target. The evidences obtained by basic science suggests a pathogenic role of hyperuricemia in the development of chronic kidney disease (CKD) and cardiovascular diseases (CVD), by inducing inflammation, endothelial dysfunction, proliferation of vascular smooth muscle cells, and activation of the renin-angiotensin system. Further, clinical evidences suggest that hyperuricemia is associated with the development of CVD and CKD. Further, accumulated data suggested that the UA-lowering treatments slower the progression of such diseases.     

Density-matrix theory of semiconductor lasers with relaxation broadening model-gain and gain-suppression in semiconductor lasers

The density-matrix theory of semiconductor lasers with relaxation broadening model is finally established by introducing theoretical dipole moment into previously developed treatments. The dipole moment is given theoretically by thek . pmethod and is calculated for various semiconductor materials. As a result, gain and gain-suppression for a variety of crystals covering wide wavelength region are calculated. It is found that the linear gain is larger for longer wavelength lasers and that the gain-suppression is much larger for longer wavelength lasers, which results in that single-mode operation is more stable in long-wavelength lasers than in shorter-wavelength lasers, in good agreement with the experiments.     

Targeted mutation in the Fas gene causes hyperplasia in peripheral lymphoid organs and liver

Fas, a type I membrane protein that transduces an apoptotic signal, is expressed in lymphocytes as well as in various tissues such as the liver, lung and heart. The mouse lymphoproliferation (lpr) mutation is a leaky mutation in Fas. By means of gene targeting, we generated a mouse strain which is completely deficient in Fas. In addition to the massive production of lymphocytes, the Fas-null mice showed substantial liver hyperplasia, which was accompanied by the enlargement of nuclei in hepatocytes. The Fas system seems to play a role in the apoptotic process to maintain homeostasis of the liver as well as the peripheral lymphoid organs.     

GaxIn1-xAsyP1-y/InP injection laser partially loaded with first-order distributed Bragg reflector

GaInAsP/InP distributed Bragg reflector (DBR) lasers with a first-order grating were demonstrated experimentally for the first time at a wavelength of 1.3 μm. Single longitudinal mode oscillation was obtained at low temperature, and the temperature dependence of the lasing wavelength was 0.7-0.8 Å/deg. The equivalent refractive index of GaInAsP at the lasing wavelength of 1.3 μm was 3.50 at 186 K.     

New 1.6 ?m wavelength GaInAsP/InP buried heterostructure lasers

1.6 ?m wavelength GaInAsP/InP buried heterostructure (b.h.) lasers were fabricated by a new process. The low threshold of 25 mA was obtained for a cavity length of about 300 ?m and stripe width of 3?5 ?m. Room temperature c.w. operation was also obtained with the threshold of 37 mA. Transverse single-mode operation up to more than three times the threshold was obtained.     

Environment‐friendly chemical recycling of aliphatic polyurethanes by hydrolysis in a CO2‐water system

In order to develop a chemical recycling system of polyurethanes (PUs), environment‐friendly hydrolysis of two types of aliphatic PUs was studied under pressured CO₂ in water, in which the carbonic acid generated from CO₂ acted as an acid catalyst. Two PUs, namely H‐PU or I‐PU, were synthesized starting from 1,4‐butanediol and 1,6‐hexamethylene diisocyanate or isophorone diisocyanate, respectively. The hydrolysis of PUs depended on the experimental conditions, such as the temperature and CO₂ pressure. As a result, 98% of H‐PU and 91% of I‐PU were successfully hydrolyzed under the typical conditions of 190 °C for 24 h at 8.0 MPa CO₂. The reaction mixtures afforded 1,4‐butanediol and diamines without the formation of any byproducts. Both of these raw materials generated from the originated PUs by selective hydrolytic cleavage of the urethane linkages, and they were easily isolated in high yields simply by evaporation of the water‐soluble components within the reaction mixture. By comparing the results of the two aliphatic PUs with those of an aromatic PU (M‐PU), the hydrolyzability was found to decrease in the order H‐PU, I‐PU, and M‐PU. The difference can be ascribed to the hydrophilicity of the aliphatic or aromatic groups connected to the urethane moieties at the terminals of PUs. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45897.     

Effect of polymer chain scission on photodegradation behavior of polystyrene/multi‐wall carbon nanotube composite

To clarify an effect of polymer chain scission on a polystyrene (PS)/multi‐wall carbon nanotube (MWNT) composite photodegradation, a relationship between the change of molecular weight and photodegradation behavior was studied. The MWNT loading brought about severe PS chain scission and led to the increase of the low molecular weight (less than 10⁵) fraction. The increase of the fraction was not proportional to the loading amount and showed the minimum at the 2% loading. The strange behavior was due to a rheological effect bringing about a decrease of shear stress in the composite preparation. An unsaturated end group was produced by the chain scission and became the photodegradation initiator leading to auto‐oxidation and crosslink reactions. The MWNT scavenged radical species and worked as an antioxidant. The coexistence of the unsaturated end group and MWNT made the photodegradation behavior complicated. However, the MWNT radical scavenging ability was considerably poor, and the MWNT had little ability to inhibit the photodegradation initiation. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40362.