Cytochrome C suppresses renal accumulation and nephrotoxicity of polymyxin B.

The receptor megalin plays an important role in the accumulation of polymyxin B (PMB) in renal cells in vitro. This study aimed to examine the effects of cytochrome c (cyto c), a typical megalin ligand, on renal accumulation and nephrotoxicity of PMB in vivo. Thirty Sprague-Dawley rats were randomly divided into the vehicle control group, PMB group, PMB + cyto c 50, 100, or 200 mg/kg group, respectively, and were treated with intravenous cyto c 30 min before the administration of PMB 4.0 mg/kg once a day for consecutive 5 days. On the 4th day after administration, 24 h urine was collected to determine N-acetyl-ß-D-glucosaminidase excretion. Six hours after the last injection on the 5th day, kidneys were harvested to assay PMB concentration and observe pathological alterations, and blood samples were collected to assay serum creatinine (SCr), blood urea nitrogen (BUN), and blood ß2-microglobulin (ß2-MG) levels. Cyto c 50, 100, and 200 mg/kg decreased the accumulation of PMB in the kidney by 18.5%, 39.1% ( p < 0.01), and 36.8% ( p < 0.01), respectively, and reduced 24 h N-acetyl-ß-D- glucosaminidase excretion by 22.5% ( p < 0.05), 40.4% ( p < 0.01), and 40.4% ( p < 0.01), respectively. Kidney pathological damage induced by PMB was markedly reduced by cyto c 100 mg/kg and 200 mg/kg. However, there were no significant differences in SCr, BUN, and blood ß2-MG levels among the groups. These results indicated that cyto c may inhibit the renal accumulation and nephrotoxicity of PMB in a rat model, further proving the role of megalin in the accumulation of PMB.

Blocking of YY1 reduce neutrophil infiltration by inhibiting IL-8 production via the PI3K-Akt-mTOR signaling pathway in rheumatoid arthritis.

Our previous study revealed that Yin Yang 1(YY1) played an important part in promoting interleukin (IL)-6 production in rheumatoid arthritis (RA). However, whether YY1 has any role in regulation of IL-8 in RA remains unclear. YY1 and IL-8 expression in RA patients were analyzed by real-time polymerase chain reaction (PCR). Ingenuity pathway analysis (IPA) was used to analyze the signaling pathway involved in YY1-induced IL-8 production. The expression of YY1 and proteins involved in the pathway were detected by Western blot and enzyme-linked immunosorbent assay (ELISA). Migration of neutrophils was performed by chemotaxis assay. In this study, we found that high expression of IL-8 was positively associated with YY1 expression in RA. Blocking YY1 expression by YY1-short hairpin (sh)RNA lentivirus reduced IL-8 production. Mechanistically, we showed YY1 activated IL-8 production via the phosphatidylinositol-3-kinase/Akt/mammalian target of rapamycin (PI3K/Akt/mTOR) signaling pathway. Further, using a co-culture system consisting of peripheral blood mononuclear cells (PBMC) and neutrophils, we found that migration of neutrophils would be inhibited by YY1 RNA interference. Finally, using the collagen-induced arthritis animal model, we showed that treatment with the YY1-shRNA lentivirus led to reduction of IL-8 levels and attenuation of inflammation and neutrophil infiltration in vivo. Our results reveal a role of YY1 involved in neutrophil infiltration in RA via the PI3K/Akt/mTOR/IL-8 signaling pathway. YY1 may be a new therapeutic target for treatment of RA.

A preliminary study on the relationship between iron and black extrinsic tooth stain in children.

Black extrinsic tooth stain, which has long troubled many people, is common among children and influences the aesthetics of teeth. The pigment was proposed to be a black insoluble ferric compound, but this is controversial. To determine whether iron exists in black stain, we collected 10 samples of black stain and 10 samples of plaque separately from children with and without black stain using sterile titanium implant curettes, and analysed the samples by inductively coupled plasma-mass spectrometry. Iron was present in both black stain and plaque, with concentrations ranging from 76·12 to 1116·88 µg g-1 . The contents of iron in black stain were significantly higher than in plaque. Because bacteria may be involved in the aetiology of black stain, we assessed the functional genes of bacteria in black stain based on 16S rRNA gene sequencing results obtained using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States. Of 253 Kyoto Encyclopedia of Gene and Genomes (KEGG) pathways tested, 56 differed in abundance between samples from children with and without black stain. Genera altered in black stain were related to many of the pathways. Some KEGG Orthology groups showed differences between black stain and plaque of control group were found to be related to iron. SIGNIFICANCE AND IMPACT OF THE STUDY: In this study, we have confirmed the existence of iron in black extrinsic tooth stain by ICP-MS. It was the first time the functional genes of bacteria in black stain were accessed and the genes associated with iron were found. These findings provided clues on the research of aetiology of black stain, which troubled millions of children. It also revealed the association between metabolic pathway of microbiota and oral phenomenon.

Comparative evaluations of cellulosic raw materials for second generation bioethanol production.

AIMS: To evaluate sugar recoveries and fermentabilities of eight lignocellulosic raw materials following mild acid pretreatment and enzyme hydrolysis using a recombinant strain of Zymomonas mobilis. METHODS AND RESULTS: Dilute acid pretreatment (2% H(2) SO(4) ) with 10% (w/v) substrate loading was performed at 134°C for 60 min followed by enzyme hydrolysis at 60°C. The results demonstrated that hydrolysis of herbaceous raw materials resulted in higher sugar recoveries (up to 60-75%) than the woody sources (<50%). Fermentation studies with recombinant Z. mobilis ZM4 (pZB5) demonstrated that final ethanol concentrations and yields were also higher for the herbaceous hydrolysates. Significant reduction in growth rates and specific rates of sugar uptake and ethanol production occurred for all hydrolysates, with the greatest reductions evident for woody hydrolysates. Further studies on optimization of enzyme hydrolysis established that higher sugar recoveries were achieved at 50°C compared to 60°C following acid pretreatment. CONCLUSIONS: Of the various raw materials evaluated, the highest ethanol yields and productivities were achieved with wheat straw and sugarcane bagasse hydrolysates. Sorghum straw, sugarcane tops and Arundo donax hydrolysates were similar in their characteristics, while fermentation of woody hydrolysates (oil mallee, pine and eucalyptus) resulted in relatively low ethanol concentrations and productivities. The concentrations of a range of inhibitory compounds likely to have influence the fermentation kinetics were determined in the various hydrolysates. SIGNIFICANCE AND IMPACT OF THE STUDY: The study focuses on lignocellulosic materials available for second generation ethanol fermentations designed to use renewable agricultural/forestry biomass rather than food-based resources. From the results, it is evident that relatively good sugar and ethanol yields can be achieved from some herbaceous raw materials (e.g. sugarcane bagasse and sorghum straw), while much lower yields were obtained from woody biomass.

Sequence analysis of the complete genome of an iridovirus isolated from the tiger frog.

We have isolated a tiger frog virus (TFV) from diseased tiger frogs, Rana tigrina rugulosa. The genome was a linear double-stranded DNA of 105,057 basepairs in length with a base composition of 55.01% G+C. About 105 open reading frames were identified with coding capacities for polypeptides ranging from 40 to 1294 amino acids. Computer-assisted analyses of the deduced amino acid sequences revealed that 39 of 105 putative gene products showed significant homology to functionally characterized proteins of other species in the GenBank/EMBL/DDBJ databases. These proteins included enzymes and structural proteins involved in virus replication, transcription, modification, and virus--host interaction. The deduced amino acid sequences of TFV gene products showed more than 90% identity to FV3, but a low degree of similarity among TFV, ISKNV, and LCDV-1. The results from this study indicated that TFV may belong to the genus Ranavirus of the family Iridoviridae.

Modeling of a deep-seated geothermal system near Tianjin, China.

A geothermal field is located in deep-seated basement aquifers in the northeastern part of the North China Plain near Tianjin, China. Carbonate rocks of Ordovician and Middle and Upper Proterozoic age on the Cangxian Uplift are capable of yielding 960 to 4200 m3/d of 57 degrees C to 96 degrees C water to wells from a depth of more than 1000 m. A three-dimensional nonisothermal numerical model was used to simulate and predict the spatial and temporal evolution of pressure and temperature in the geothermal system. The density of the geothermal water, which appears in the governing equations, can be expressed as a linear function of pressure, temperature, and total dissolved solids. A term describing the exchange of heat between water and rock is incorporated in the governing heat transport equation. Conductive heat flow from surrounding formations can be considered among the boundary conditions. Recent data of geothermal water production from the system were used for a first calibration of the numerical model. The calibrated model was used to predict the future changes in pressure and temperature of the geothermal water caused by two pumping schemes. The modeling results indicate that both pressure and temperature have a tendency to decrease with time and pumping. The current withdrawal rates and a pumping period of five months followed by a shut-off period of seven months are helpful in minimizing the degradation of the geothermal resource potential in the area.

Mineralized nodule formation by human dental papilla cells in culture.

Human dental papilla cells were enzymatically separated from deciduous tooth germs of an 8-month-old embryo legally aborted. The second passage cells were cultured up to 35 days in 3 groups. The beta-GP group was cultured in the Dulbecco MEM containing ascorbic acid and beta-glycerophosphate supplemented with 15% fetal bovine serum. The Dex group was in the same medium, in addition containing dexamethasone. The control group contained none of the 3 chemicals. Mineralized nodules were formed after 15 days in the beta-GP and Dex groups. Only in the presence of ascorbic acid and organic phosphate did they mineralize. The addition of dexamethasone caused a significant increase in the number of nodules. By electron microscopy, the nodules contained needle-shaped crystals associated with a network of collagen fibrils. Calcium and phosphorus were detected by energy-dispersive X-ray microanalysis in the nodules. Furthermore, the crystalline material exhibited a pattern consistent with hydroxyapatite and dentin when examined by X-ray diffractometry. Cells showed high levels of alkaline phosphatase activity, which was increased 2-3 times in the presence of the 3 chemicals. These results indicated that human dental papilla cells have the ability to form dentin in culture. The formation of mineralized nodules by human dental papilla in vitro provides a useful model for studying the morphogenesis and differentiation of dental papilla ectomesenchyme.

Interspecies-specific ovarian autoantigens involved in neonatal thymectomy-induced murine autoimmune oophoritis.

PROBLEM: Thymectomy of mice on day 3 after birth (3d-Tx) gives rise to the appearance of a particular type of ovarian lesion known as experimental autoimmune oophoritis (AIO). METHOD: In the present study, the spleen cells from BALB/c mice having undergone 3 day-Tx AIO were fused with X63-Ag8-6.5.3 myeloma cells, and a number of hybridoma clones producing autoantibodies against ovarian tissue were established. RESULTS: On the basis of immunohistochemical and protein-chemical analysis, two independent clones, designated at T2.2 and S1.6, were found to react with interstitial tissues surrounding the follicles. These monoclonal antibodies showed broad cross-species reactivity, in that they recognized similar antigenic macromolecules in the rat, pig, human, and mouse. The antigenic determinants were strongly resistant to heat and acid, especially to the treatment of periodic acid, indicating that the antigenic determinants had no relation with carbohydrate components. CONCLUSIONS: By antibody affinity chromatography, two kinds of autoantigens were identified. SDS-PAGE, under reduced or nonreduced conditions, revealed an 80/85 kDa protein for T2.2, and an 82 kDa for S1.6, respectively.

[Laparoscopic cholecystectomy. A report of 100 cases].

From February to May in 1991, 100 cases of gallstones underwent the attempt of laparoscopic cholecystectomy. There were two failures owing to extensive adhesion. The operative time was 72.5 +/- 32 minutes in the first 50 cases, and 46.9 +/- 15 minutes thereafter. Among them 8 cases were coelio-drained for 24 hours with very little thin bloody drainage. There were not postoperative complications. The hospital stay was 3-7 days. All patients were back to their normal daily-work within 10 days. Hence this new type of cholecystectomy is characterized by less trauma and pain, and fast postoperative recovery.