Head-shape polymorphism in Japanese eels Anguilla japonica in relation to differences of somatic growth in freshwater and brackish habitats

The age, total length (L(T)), head shape and skull shape were investigated for 379 Japanese eels Anguilla japonica sampled in freshwater and brackish areas of the Kojima Bay-Asahi River system, Okayama, Japan, to learn about the differentiation process of head-shape polymorphism. The relative mouth width (ratio of mouth width to L(T)) of A. japonica > 400 mm L(T) collected in fresh water was significantly greater than that of fish collected in brackish water. Growth rates of mouth width and the distance from the snout to the midpoint of the eyes (the ratio of width and distance to age, respectively) were not significantly different between freshwater and brackish-water samples, whereas the somatic growth rate (the ratio of L(T) to age) of freshwater samples was significantly lower than that of brackish-water eel samples. These results suggest that the factors affecting head and somatic growth of A. japonica are not identical. According to these results and feeding patterns in each habitat reported by another study, it is suggested that somatic growth appears to play a significant role in the differentiation process of the head-shape polymorphism in A. japonica, with the slow-growing fish in fresh water becoming broad-headed and the fast-growing fish in brackish water becoming narrow-headed.

Early treatment with olmesartan prevents juxtamedullary glomerular podocyte injury and the onset of microalbuminuria in type 2 diabetic rats

BACKGROUND

Studies were performed to determine if early treatment with an angiotensin II (Ang II) receptor blocker (ARB), olmesartan, prevents the onset of microalbuminuria by attenuating glomerular podocyte injury in Otsuka Long-Evans Tokushima Fatty (OLETF) rats with type 2 diabetes mellitus.

METHODS

OLETF rats were treated with either a vehicle, olmesartan (10 mg/kg/day) or a combination of nonspecific vasodilators (hydralazine 15 mg/kg/day, hydrochlorothiazide 6 mg/kg/day, and reserpine 0.3 mg/kg/day; HHR) from the age of 7-25 weeks.

RESULTS

OLETF rats were hypertensive and had microalbuminuria from 9 weeks of age. At 15 weeks, OLETF rats had higher Ang II levels in the kidney, larger glomerular desmin-staining areas (an index of podocyte injury), and lower gene expression of nephrin in juxtamedullary glomeruli, than nondiabetic Long-Evans Tokushima Otsuka (LETO) rats. At 25 weeks, OLETF rats showed overt albuminuria, and higher levels of Ang II in the kidney and larger glomerular desmin-staining areas in superficial and juxtamedullary glomeruli compared to LETO rats. Reductions in mRNA levels of nephrin were also observed in superficial and juxtamedullary glomeruli. Although olmesartan did not affect glucose metabolism, it decreased blood pressure and prevented the renal changes in OLETF rats. HHR treatment also reduced blood pressure, but did not affect the renal parameters.

CONCLUSIONS

This study demonstrated that podocyte injury occurs in juxtamedullary glomeruli prior to superficial glomeruli in type 2 diabetic rats with microalbuminuria. Early treatment with an ARB may prevent the onset of albuminuria through its protective effects on juxtamedullary glomerular podocytes.

Interferon-gamma enhances superoxide production in human mesangial cells via the JAK-STAT pathway

Immune reactive cytokines, such as interferon (IFN)-gamma, have multiple effects in glomerulonephritis. Superoxide anions (O(2)(-)), which are associated with the progression of glomerulonephritis, are mainly generated by nicotinamide adenine dinucleotide phosphate (reduced form) NAD(P)H oxidases. We determined the effects of IFN-gamma on O(2)(-) production, phosphorylation of signal transducer and activator of transcription (STAT)-1alpha, and the mRNA and protein expressions of p22phox and Nox1, components of NAD(P)H oxidases, in human mesangial cells (HMCs). Significant increases in O(2)(-) production with IFN-gamma were completely abolished by the flavin-containing enzyme inhibitor, diphenyleneiodonium (10 micromol/l), and the Janus-activated kinase (JAK)2 inhibitor, AG490 (100 micromol/l). Phosphorylated STAT-1alpha was detected after 5 min of IFN-gamma stimulation using Western blot analysis, and binding to the gamma-activating site was observed from 30 min to 4 h, thereafter by electrophoretic mobility shift assay (EMSA). Super-shift analysis in EMSA revealed that the main transcription factor was STAT-1alpha. IFN-gamma significantly increased the expression of p22phox mRNA and protein, although expression was inhibited by AG490. These data suggest that IFN-gamma stimulates O(2)(-) production in HMCs via the JAK-STAT pathway and NAD(P)H oxidase.

Wetting characteristics and blood clotting on surfaces of copoly(gamma-Benzyl-L-glutamate, gamma-hydroxyethyl-L-glutamine)

The film surface of poly(gamma-benzyl-L-glutamate) (PBLG) was modified with 2-aminoethanol to enhance its hydrophilicity. Controlling the reaction conditions of PBLG and 2-aminoethanol, various types of copoly(gamma-benzyl-L-glutamate, gamma-hydroxyethyl-L-glutamine) film surfaces were obtained. Surface free energy (gamma sv), the dispersive component of gamma sv (gamma dsv), the nondispersive component of gamma sv (gamma psv), and the interfacial free energy of polymer surface with water (gamma sw), which were obtained by using the contact angle measurement and calculation method proposed by Andrade et al., were changed remarkably by the aminolysis. The gamma sv value increased after 2 h of aminolysis from 48.2 (PBLG) to 65.3 dyn/cm and gradually increased to around 70 dyn/cm after 12 h reaction. (gamma dsv) and (gamma psv) changed from 31.0 and 17.2 dyn/cm (PBLG) to 26.5 and 44.3 dyn/cm, respectively. These parameters of the material surfaces, modified over 12 h reaction, were found to be similar to those of the surfaces of canine aorta, vein, and human fibrin membrane. Blood clotting times on these polymer surfaces were comparatively longer than on siliconized glass surfaces.

Wetting characteristics and blood clotting on surfaces of acylated chitins

Various acylated chitins, including formyl, acetyl, propionyl, butyryl, caproyl, capryl, lauroyl, and benzoylchitin, were evaluated as materials for blood contact surfaces by means of contact angle and blood-clotting time measurements. Critical surface tensions of acylated chitins varied within the range of 20-30 dyn cm-1 and were dependent on the length of the acyl side chains. Furthermore, the dispersion and nondispersion components of the surface tension show remarkable differences which are dependent on the type of acyl group attached to chitin. The chitin derivative with 2.0 acetyl groups per N-acetylglucosamine residue gave values of the dispersive and nondispersive components of the surface tension that are very close to those obtained for glutaraldehyde-treated umbilical cord vessels. All of the acylated chitin surfaces show longer clotting times than the original chitin surface.