Measurements of OH reactivity and photochemical ozone production in the urban atmosphere

Measurements of OH reactivity (i.e., OH loss rates) in the troposphere are essential for discussing tropospheric OH photochemistry. In July and August 2003, we observed the total OH reactivity in a suburban area of Tokyo. More than 90% of the data of the measured OH loss rates were higher than the calculated values with simultaneously measured concentrations of various trace species even though the rate coefficient of the OH + NO2 reaction was measured by us. We concluded that this discrepancy is due to the existence of unmeasured volatile organic compounds (VOCs). We estimated the potential of the photochemical ozone production in the case of including the unknown species as VOCs and excluding the missing sink, respectively. When the unknown species were included as VOCs, the potential increases from 32% to 88%. This result indicates the photochemical production rates of ozone in the urban air are substantially greater than expected.     

Bioactive constituents of Chinese natural medicines. III. Absolute stereostructures of new dihydroflavonols, hovenitins I, II, and III, isolated from hoveniae semen seu fructus, the seed and fruit of Hovenia dulcis THUNB. (Rhamnaceae): inhibitory effect on alcohol-induced muscular relaxation and hepatoprotective activity

The methanol-soluble fraction from a Chinese natural medicine Hoveniae Semen Seu Fructus, the seed and fruit of Hovenia dulcis THUNB. (Rhamnaceae) was found to show an inhibitory effect on the alcohol-induced muscular relaxation and a protective activity on the D-galactosamine/lipopolysaccharide or carbon tetrachloride-induced liver injury. Through bioassay-guided separation using a traction performance test, three new dihydrofravonols named hovenitins I, II, and III were isolated from Hoveniae Semen Seu Fructus together with four known flavonoids, (+)-ampelopsin, laricetrin, myricetin, and (+)-gallocatechin. The absolute stereostructures of hovenitins I, II, and III were determined on the basis of chemical and physicochemical evidence to be (2R, 3R)-5,7,4',5'-tetrahydroxy-3'-methoxydihydroflavonol, (2R,3S)-5,7,4',5'-tetrahydroxy-3'-methoxy-dihydroflavonol, and (2R, 3S)-5,7,3',4',5'-pentahydroxydihydro-flavonol, respectively. Hovenitin I and (+)-ampelopsin, both of which were principal ingredients of the active fractions from this natural medicine, were found to show an inhibitory activity on the ethanol-induced muscle relaxation in rats. In addition, hovenitin I showed a protective activity on the liver injury induced by D-galactosamine/lipopolysaccharide or carbon tetrachloride in mice.     

Determination of ocular toxicity in multiple applications of foscarnet iontophoresis

This is the first study of multiple applications of drug iontophoresis in the eye. We repeated ocular foscarnet iontophoresis in 10 eyes of 10 rabbits every third day at the same paralimbal site for a total of seven applications over a period of 21 days to determine the efficacy and toxicity of multiple applications of ocular foscarnet iontophoresis. Mean vitreous human foscarnet concentration of 189 +/- 50.6 microM (SD) was achieved four hours after the seventh consecutive iontophoretic application over a period of twenty-one days. These levels were within the therapeutic range (25-800 microM) for the treatment of CMV retinitis and comparable to the intravitreal foscarnet concentrations achieved in eyes treated with a only a single application of ocular iontophoresis. Electroretinography (ERG) and Slit-lamp biomicroscopy responses revealed no evidence of ocular toxicity. Indirect ophthalmoscopy of the retinas and gross examinations of the calottes revealed a single, small burn in the retina and choroid corresponding to the application site of the iontophoresis probe similar to the lesion resulting from a single application of iontophoresis. Light and electron microscopy revealed local tissue injury and fibrosis at the iontophoresis site, but adjacent areas were unaffected.     

Serum hyaluronic acid as a reliable parameter of allograft viability in porcine liver transplantation

BACKGROUND/AIMS: Hyaluronic acid is an endogenous glycosaminoglycan which is selectively degraded by hepatic sinusoidal endothelial cells. We evaluated the significance of serum hyaluronic acid clearance as an early indicator of allograft viability in porcine liver transplantation. MATERIALS AND METHODS: According to the survival period, animals were divided into two groups: Group I (n = 8) for survival equal or over four days and Group II (n = 5) for survival less than four days. Serial serum hyaluronic acid concentrations were measured before and after reperfusion in the recipient. RESULTS: In both groups, serum hyaluronic acid levels during the anhepatic period increased rapidly 9-fold from the preoperative value due to the absence of clearance by hepatic endothelial cells. In Group I, serum hyaluronic acid peaked at 15 min postreperfusion and decreased thereafter. In contrast, Group II failed to show clearance of hyaluronic acid after reperfusion. The serum hyaluronic acid value 120 min after reperfusion was 1,029 +/- 357 micrograms/L in Group I, and 1,856 +/- 263 micrograms/L in Group II (p < 0.01). Conventional parameters of liver function such as aspartate transaminase, lactic dehydrogenase, ammonia, lactate, and total bile acids were comparable between the two groups. CONCLUSIONS: The clearance of the serum hyaluronic acid reflects hepatic sinusoidal endothelial cell function and is a reliable and early marker of hepatic allograft viability.     

Functional interdependence of DNA polymerizing and 3'->5' exonucleolytic activities in Pyrococcus furiosus DNA polymerase I

Pyrococcus furiosus DNA polymerase I (Pol BI) belongs to thefamily B (     

Increased proteolytic processing of protein tyrosine phosphatase mu in confluent vascular endothelial cells: the role of PC5, a member of the subtilisin family

Cleavage and subsequent release of the extracellular domains of receptor protein tyrosine phosphatases (RPTP) occur at high cell density and may have an important role in regulating their activity. Because cleavage of RPTP occurs at a target motif (RXK/RR) recognized by a family of subtilisin/kexin-like endoproteases, we postulated that members of the subtilisin family may have an important role in this cleavage. We show in this report that the membrane-associated RPTPmu--both in its full 200-kDa form and as a 100-kDa cleavage product--is upregulated 4- and 7-fold, respectively, as human umbilical vein endothelial cells (HUVEC) approach confluence. To determine whether RPTPmu cleavage depended on PC5 (a subtilisin/kexin like endoprotease present in endothelial cells), we transfected COS cells with expression plasmids coding for RPTPmu and PC5 or the closely related protease PACE4. PC5, but not PACE4, cleaved RPTPmu, and RPTPmu cleavage was absent in COS cells transfected with an expression plasmid encoding a mutant PC5 whose active-site serine had been mutated to alanine. We also performed RNA blot analysis to determine whether PC5 expression was affected by confluence in HUVEC. PC5 mRNA levels were upregulated by more than 30-fold when confluence in HUVEC increased from 25% to 100%. These results indicate that PC5 may have an important role in mediating the cleavage of RPTPmu in response to contact inhibition in HUVEC.     

Experimental Toxoplasma retinitis: a light and electron microscopical study

In a light and electron microscopical study of the morphological lesions of acute experimental Toxoplasma retinitis in the rabbit, produced by intravitreal inoculation with RH strain T gondii, all layers of the retina were found to be infected with the parasite. The Bruch membrane appeared to be a relatively impermeable barrier to invasion by the parasite. The underlying choroid showed an inflammatory cellular infiltrate but was free of organisms. Evidence of lateral spread of infection between the layers of the retinal tissue was observed. Examples of glial cell infection were also seen. Trophozoities may enter the brain by spreading along contiguous glial cell elements of the optic nerve; retinal tissue destruction occurs by direct invasion of cells by trophozoites. In other areas, tissue destruction by inflammatory cells occurred in the absence of organisms and may indicate an immunologically induced process of tissue destruction.     

Application of graft copolymers using macromonomer method to two-component polyurethane coatings

Graft copolymers as acrylic polyols in two-component polyurethane coatings were prepared by the free-radical copolymerization of methyl methacrylate, n-butyl methacrylate, n-butyl acrylate, acrylic acid, 2-hydroxyethyl methacrylate and poly(methyl methacrylate)-macromonomers. The poly(methyl methacrylate) macromonomer was prepared by the polymerization of methyl methacrylate in the presence of thiopropionic acid as a transfer agent followed by the reaction with glycidyl methacrylate. These polymers, whose numbers of poly(methyl methacrylate) macromonomer branches and the molecular weights of the poly(methyl methacrylate) macromonomer branches were controlled, offer an advantage over conventional resins with respect to the application/appearance of coatings as well as the final film properties. Some of these advantages were higher solids and a better control of the coating rheology, an increase in the cross-linking reactivity of the polyols with polyisocyanate and improvement in film toughness. The change in the morphological structure of the films under tensile stress was of particular interest.     

Renoprotective effect of enalapril in uninephrectomized spontaneously hypertensive rats with neonatal streptozotocin-induced diabetes

We compared the renoprotective effect between angiotensin-converting enzyme inhibitor, enalapril, and a dihydropyridine-type calcium channel blocker, nicardipine, in a severe form of renal injury in rats. Two-day-old spontaneously hypertensive rats (SHR) were injected with streptozotocin or vehicle as control. UNX was performed at 3 weeks of age, and enalapril or nicardipine was administered in drinking water from 7 weeks of age. Uninephrectomy (UNX) markedly exacerbated hypertension and renal injury in the nondiabetic and diabetic SHR. Enalapril and nicardipine comparably reduced blood pressure in UNX diabetic SHR. However, serum creatinine was significantly elevated in the nicardipine-treated group as compared with the enalapril-treated group at 24 weeks of age (nicardipine-treated group, 67 +/- 4 microM; enalapril-treated group, 49 +/- 3 microM; P < 0.01; untreated group 57 +/- 4 microM). Furthermore, the incidence of glomerular sclerosis was similar between untreated and nicardipine-treated groups, whereas it tended to be reduced in the enalapril-treated group. In a separate experiment of diabetic SHR without UNX, enalapril therapy significantly ameliorated hyperglycemia and albuminuria (P < 0.01). This study showed that a renoprotective effect was seen in enalapril but not in nicardipine in UNX diabetic SHR despite the comparable reduction of blood pressure. This suggests that enalapril may be more effective than nicardipine in delaying the progression of a severe form of diabetic nephropathy.