[The expression and role of somatostatin and its receptors in the developing retina].

The possible role of somatostatin (SRIF) and its receptors in mammalian retinal maturation is reviewed in the present paper. SRIF is characterized by early appearance, transient features and achievement of mature pattern at the time of eye opening. SRIF has an important role in the development of the retina and of retinofugal projections.

SNP identification and analysis in part of intron 2 of goat MSTN gene and variation within and among species.

Part of intron 2 of the myostatin (MSTN) gene of 140 goats from 24 populations and 38 sheep from 8 breeds were sequenced, and similar sequences of different species from Gene bank were also obtained to study MSTN diversity within and among species. The results indicated that there were seven polymorphic sites in the sequenced region of goat, which have not been separated by recombination (or recurrent mutation), presented complete linkage disequilibrium, and could be sorted into three haplotypes. There was no polymorphic site in the sequenced region of sheep. The haplotype diversity, nucleotide diversity, and average number of single nucleotide polymorphism (SNP) differences of goats from the South group are higher than those of North group, and the corresponding value of the Foreign group is also higher than that of Chinese. The genetic differentiation (0.7558) between the Foreign and Chinese group is significant. There are two main haplotypes of the MSTN intron 2 in the goat, which may represent two ancestral types, in support of the theory that domestic goats in the world mainly originated from two ancestors based on morphology, history, archaeology, and molecular markers. The sequence differences of the MSTN intron 2 among species are greater than those within species.

Pyruvate improves neutrophilic nitric oxide generation in peritoneal dialysis solutions.

To investigate the effects of pyruvate (Pyr)-based peritoneal dialysis solutions (P-PDS) on neutrophilic nitric oxide (NO) generation, we incubated human peripheral neutrophils in dL-lactate (Lac, 40 mM)-based PDS and equimolar P-PDS, and Hanks' balanced salt solution at various pH and high glucose (HG) levels, respectively. The production of NO in various test solutions was determined based on the Griess reaction. Acidic pH, high Lac, and HG induced an acute and substantial inhibition of neutrophilic NO, whereas Pyr in PDS significantly improved the NO generation in both acidic pH and physiological pH, and also in HG conditions. The Pyr protection may be associated with the improvement of glucose metabolic pathways in addition to its alkalization.

Existence and significance of hepatitis B virus DNA in kidneys of IgA nephropathy.

AIM: To investigate the existence and significance of hepatitis B virus (HBV) DNA in the pathogenesis of IgA nephropathy (IgAN). METHODS: Fifty cases of IgAN with HBV antigenaemia and/or hepatitis B virus antigens (HBAg, or HBsAg, HBcAg) detected by immunohistochemistry in renal tissues were enrolled in our study. The distribution and localization of HBV DNA were observed using in situ hybridization. Southern blot analysis was performed to reveal the state of renal HBV DNA. RESULTS: Among the 50 patients with IgAN, HBs antigenemia was detected in 17 patients (34%). HBAg in renal tissues was detected in 48 patients (96%), the positive rate of HBAg, HBsAg, and HBcAg was 82% (41/50), 58% (29/50), and 42% (21/50) in glomeruli, respectively; and was 94% (47/50), 56% (28/50) and 78% (39/50) in tubular epithelia, respectively. Positive HBV DNA was detected in 72% (36/50) and 82% (41/50) cases in tubular epithelia and glomeruli respectively by in situ hybridization, and the positive signals were localized in the nuclei of tubular epithelial cells and glomerular mesangial cells as well as infiltrated interstitial lymphocytes. Moreover, 68% (34/50) cases were proved to be HBV DNA positive by Southern blot analysis, and all were the integrated form. CONCLUSION: HBV infection might play an important role in occurrence and progress of IgAN. In addition to humoral immune damages mediated by HBAg-HBAb immune complex, renal tissues of some IgAN are directly infected with HBV and express HBAg in situ, and the cellular mechanism mediated by HBV originating from renal cells in situ may also be involved in the pathogenesis of IgAN.

NF-kappa B involved in transcription enhancement of TGF-beta 1 induced by Ox-LDL in rat mesangial cells.

BACKGROUND: To determine the binding activity of nuclear factor-kappa B (NF-kappa B) and the transcription of transforming growth factor-beta 1 (TGF-beta 1) induced by oxidized low density lipoprotein (Ox-LDL) in rat mesangial cells and to elucidate the mechanism of renal injury of Ox-LDL. METHODS: NF-kappa B binding activity was measured by gel shift assay in mesangial cells with or without inducement of Ox-LDL. Protein kinase inhibitors and activators were then used to determine the signal transduction pathways. In this course I kappa B protein expression was analyzed by Western blot assay. TGF-beta 1 mRNA was measured in mesangial cells exposed to Ox-LDL by RT-PCR assay. TGF-beta 1 promoter from -1551 to +57 were constructed into a pGL3-Basic vector with a luciferase reporting gene. A putative binding site of NF-kappa B was mutated. The wild and mutant promoters activity was analyzed by transfection into mesangial cells. RESULTS: NF-kappa B was activated by Ox-LDL persistently and rebounded in the early period. Ox-LDL induced NF-kappa B activation in a dose dependent way. It also induced I kappa B degradation in 2 hours and resumed to normal levels. NF-kappa B activation was not alleviated by inhibitors of protein kinase A (PKA), extracellular signal-regulated kinase (ERK), and p38 MAP kinase (p38MAPK). Inhibitors of protein kinase C (PKC) and proteinsome inhibited the enhancement of NF-kappa B binding activity. Ox-LDL induced the transcription of TGF-beta1 in a time and dose dependent manner. Mutation of the putative binding site of NF-kappa B reduced the activity of TGF-beta1 promoter. CONCLUSION: Ox-LDL induced activation of NF-kappa B persistently. It was probably regulated by the degradation of I kappa B mediated by PKC pathway. NF-kappa B may be involved in the enhancement of TGF-beta 1 induced by Ox-LDL in rat mesangial cells.

Role of hepatitis B virus infection in pathogenesis of IgA nephropathy.

AIM: To investigate the role of hepatitis B virus (HBV) in the pathogenesis of IgA nephropathy (IgAN). METHODS: HBV antigens (HBAg, or HBsAg, HBcAg, and HBeAg) in renal tissues with IgAN were detected by immunohistochemical technique. The distribution and localization of HBV DNA were observed by using in situ hybridization. Southern blot analysis was performed to reveal the state of renal HBV DNA. RESULTS: Among 100 patients with IgAN, HBs antigenemia was detected in 18 patients (18.00 %). HBAg in renal tissues was detected in 31 patients (31.00 %), the positive rate of HBAg, HBsAg and HBcAg was 64.52 % (20/31), 32.26 % (10/31), 32.26 % (10/31), respectively in glomeruli. HBcAg was also found in tubular epithelia and interstitia, which was 45.16 % (14/31) and 6.45 % (2/31), respectively. Five out of six cases with positive HBV DNA by in situ hybridization were proved to be HBV DNA positive by Southern blot analysis, and all were of the integrated form. Eight specimens were demonstrated to be HBV DNA positive by in situ hybridization, which was localized in the nuclei of tubular epithelial cells and glomerular mesangial cells as well as in infiltrated interstitial lymphocytes. CONCLUSION: There is a relationship between HBV infection and IgAN. In addition to the humoral immune damage mediated by HBAg-HBAb immune complex, the cellular mechanism mediated by HBV originating from renal cells in situ may be also involved in the pathogenesis of IgAN.

Oxidized LDL induces transcription factor activator protein-1 in rat mesangial cells.

It has been shown that oxidized low-density lipoprotein (ox-LDL), through the activation of glomerular cells, stimulates pathobiological processes involved in monocyte infiltration into the mesangium. The underlying molecular mechanisms are not fully understood. The present study showed that ox-LDL strongly induced AP-1 binding activity in rat mesangial cells (RMCs) in a dose- and time-dependent manner, reaching the maximal activation at 250 microg ml(-1) within 24 h. The results from mobility shift assays and Western blotting analysis revealed that this AP-1 binding increase involved c-Jun, but not c-Fos. Moreover, this ox-LDL-increased AP-1 binding was inhibited by several protein kinase (PK) inhibitors: the protein kinase C (PKC) inhibitor Bisindolylmaleimide I, the cAMP-dependent PK (PKA) inhibitor H89, and the tyrosine PK (PTK) inhibitor genistein. Protein phosphorylation represents mitogen-activated protein kinase (MAPK) activity. Therefore, we examined the role of ox-LDL on the activation of mesangial cell JNK/SAPK, the only recognized protein kinase that catalyses phosphorylation of c-Jun. The incubation of mesangial cells with ox-LDL induced phosphorylation of JNK1/SAPK dose dependently, with the maximal response at 150 microg ml(-1). This study demonstrates that multiple kinase activities are involved in the mechanism of ox-LDL-induced AP-1 activation in mesangial cells, and ox-LDL stimulates AP-1 through JNK-c-Jun other than MEK-c-Fos signalling pathway.

[Role of hepatitis B virus infection in pathogenesis of IgA nephropathy].

OBJECTIVE: To clarify the relationship between hepatitis B virus (HBV) infection and IgA nephropathy (IgAN). METHODS: HBV antigen (HBAg) in renal tissues of the patients with IgAN was detected by immunohistochemical technique, the carrier status and localization of HBV DNA in renal tissues were determined by Southern blot analysis and in situ hybridization. RESULTS: Serum HBsAg was detected in 18 of the 100 patients with IgAN (18%), HBAg was detected in 31 of 100 patients (31%) in their renal tissue and in 20 of 31 patients (65%) in their glomeruli, and both HBsAg and HBcAg were detected in 10 of 31 patients (32%), respectively. HBcAg was also found in tubular epithelia (45%, 14/31) and renal interstitium (6%, 2/31), respectively. Five of six cases were proved to be positive of integrated-form HBV DNA in their renal tissue by Southern blot analysis. In situ hybridization demonstrated that HBV DNA was 8/8 and 6/8 positive in their renal tubules and glomeruli of all eight specimens, localized in the nucleus of tubular epithelial cells, glomerular mesangial cells, as well as infiltrated interstitial lymphocytes. CONCLUSION: HBV infection closely related with IgAN and HBV infection might be involved in pathogenesis of IgAN.

Pyruvate preserves neutrophilic superoxide production in acidic, high glucose-enriched peritoneal dialysis solutions.

AIM: To investigate effects of pyruvate (Py)-based peritoneal dialysis solutions (P-PDS) on neutrophilic superoxide (O2-) production against high glucose (HG) concentrations at acidic or physiologic pH value, and explore potential mechanisms. METHODS: Human neutrophils were incubated with both dl-lactate (La, 40 mM)-based PDS (L-PDS) and equimolar P-PDS at various pH and HG levels, respectively. Hanks' balanced salt solution (HBSS) served as controls. O2- generation was determined by the reduction of ferricytochrome c. RESULTS: Acidic pH and high La induced acute and substantial inhibitions of O2- production. HG in both PDS and HBSS resulted in a suppression of O2- in a dose-dependent manner. P-PDS generated near twofold O2- formation of L-PDS counterparts at various pH and HG levels. P-PDS with HG produced significantly more O2- than Py-free HBSS counterparts. CONCLUSIONS: Py in PDS effectively protected neutrophils from HG-induced inhibition of O2- production, even at a physiological pH. The Py cytoprotection may be associated with the preservation of carbohydrate metabolic pathways in addition to its alkalization.