The distribution of different virulence grass carp reovirus strains in some neglected tissues.

Grass carp reovirus (GCRV) is the causative agent of hemorrhagic disease in infected grass carp. During an outbreak, a mortality rate of up to 85% can be experienced, thus leading to substantial economic losses. The current understanding of disease pathogenesis is limited, with the distribution and dynamics of replication amongst different GCRV strains in vivo largely unknown. We determined distribution of different GCRV strains in infected grass carp, especially in some neglected tissues, such as the gill, brain, blood and so on. The results showed elevated viral RNA copy numbers in the blood, with some tissues such as the kidney, heart, brain, and bladder exhibiting even higher viral loads following infection with the virulent GCRV-CL strain. Even more interesting is that the brain exhibited the highest viral load, with a copy number of 800,000 following GCRV-CL infection. Overall, this study provides further insight into GCRV viral load distributions following infection and potentially identified some new viral tropism sites to provide a foundation for further studies aimed at characterizing GCRV viral pathogenesis.

Expression of intronic miRNAs and their host gene Igf2 in a murine unilateral ureteral obstruction model

The objective of this study was to determine the expression of miR-483 and miR-483* and the relationship among them, their host gene (Igf2), and other cytokines in a murine model of renal fibrosis. The extent of renal fibrosis was visualized using Masson staining, and fibrosis was scored 3 days and 1 and 2 weeks after unilateral ureteral obstruction (UUO). Expression of miR-483, miR-483* and various cytokine mRNAs was detected by real-time polymerase chain reaction (PCR). Expression of miR-483 and miR-483* was significantly upregulated in the UUO model, particularly miR-483 expression was the greatest 2 weeks after surgery. Additionally, miR-483 and miR-483* expression negatively correlated with Bmp7 expression and positively correlated with Igf2, Tgfβ, Hgf, and Ctgf expression, as determined by Pearson's correlation analysis. Hgf expression significantly increased at 1 and 2 weeks after the surgery compared to the control group. This study showed that miR-483 and miR-483* expression was upregulated in a murine UUO model. These data suggest that miR-483 and miR-483* play a role in renal fibrosis and that miR-483* may interact with miR-483 in renal fibrosis. Thus, these miRNAs may play a role in the pathogenesis of renal fibrosis and coexpression of their host gene Igf2.

Expression of intronic miRNAs and their host gene Igf2 in a murine unilateral ureteral obstruction model.

The objective of this study was to determine the expression of miR-483 and miR-483* and the relationship among them, their host gene (Igf2), and other cytokines in a murine model of renal fibrosis. The extent of renal fibrosis was visualized using Masson staining, and fibrosis was scored 3 days and 1 and 2 weeks after unilateral ureteral obstruction (UUO). Expression of miR-483, miR-483* and various cytokine mRNAs was detected by real-time polymerase chain reaction (PCR). Expression of miR-483 and miR-483* was significantly upregulated in the UUO model, particularly miR-483 expression was the greatest 2 weeks after surgery. Additionally, miR-483 and miR-483* expression negatively correlated with Bmp7 expression and positively correlated with Igf2, Tgfß, Hgf, and Ctgf expression, as determined by Pearson's correlation analysis. Hgf expression significantly increased at 1 and 2 weeks after the surgery compared to the control group. This study showed that miR-483 and miR-483* expression was upregulated in a murine UUO model. These data suggest that miR-483 and miR-483* play a role in renal fibrosis and that miR-483* may interact with miR-483 in renal fibrosis. Thus, these miRNAs may play a role in the pathogenesis of renal fibrosis and coexpression of their host gene Igf2.

Bandwidth improvement for slow light using amplification characteristics of cascaded vertical-cavity surface-emitting lasers.

A scheme to improve the bandwidth of slow light using cascaded vertical-cavity surface-emitting lasers (VCSELs) is proposed and experimentally demonstrated. In the scheme, a proper adjustment on the gain peaks of two cascaded VCSELs enables the generation of the desired composite gain spectrum, which has flat-top gain and delay profiles with enhanced peak values. By employing the improved gain and delay profiles in a slow light system, a large delay can be achieved within a wider bandwidth. In the experiment, by using two cascaded VCSELs, a tunable slow light up to 135 ps for a 5 Gbits/s pseudorandom binary sequence is demonstrated with relatively low signal distortion.

Application of antibodies for the identification of polysaccharide gum additives in processed foods.

Anti-carbohydrate antibodies with specificities for polysaccharide gums were isolated from the serum of rabbits that were immunized with a solution of the gums and Freund's complete adjuvant. The primary objective was to test an immunological method for the detection of the polysaccharide gums as additives to processed foods. Analysis involved the extraction of food with phosphate buffer and the testing of the extract for a reaction with anti-gum antibodies by the agar diffusion method. Reaction by a specific gum with the homologous antibodies establishes the presence of the gum in the food. The method is a novel application of antibodies. The antibody method is highly specific for a gum and thus possesses advantages over other methods of analysis for polysaccharide gums as additives in processed foods.

The direct electrochemistry of myoglobin at a DL-homocysteine self-assembled gold electrode.

A pair of well-defined redox waves of myoglobin at a DL-homocysteine self-assembled gold electrode was achieved. Myoglobin can strongly bind to the homocysteine self-assembled gold electrode, so the Mb-Hcy self-assembled gold electrode was prepared and the standard rate constant (ks) of Mb was calculated as 9.3 x 10(-1) s(-1). X-ray photoelectron spectroscopy (XPS) measurements demonstrated that Hcy monolayer was formed and Mb was bound to Hcy monolayer.

Electrochemical studies of rutin interacting with hemoglobin and determination of hemoglobin.

Electrochemical investigation of the interaction of rutin (Rt) with hemoglobin (Hb) at a glassy carbon electrode is reported for the first time. With the addition of hemoglobin in a rutin solution, both the reduction and oxidation currents decrease with few changes in the peak potentials. The reaction of rutin with hemoglobin forms a nonelectroactive supramolecular complex Hb-Rt. The equilibrium constant for complex is calculated to be 3.4x10(6). A satisfactory result has been obtained for the determination of hemoglobin in clinical blood samples.

Iron status and stores decline with age in Lewis rats.

In the context of a larger study examining the interaction of vitamin A (VA) status and age on immune function, we examined age-related changes in hematologic and iron status variables in male Lewis rats. Animals were fed a nutritionally adequate purified diet containing either 0.35 (marginal), 4.0 (control) or 50 (supplemented) mg retinol equivalents (as retinyl palmitate) per kg of diet from the time of weaning until killing at 8-10 (middle-aged) or 20-22 (old) mo of age. Neither VA nor VA and age interaction effects were significant for most iron variables examined. After controlling for body weight, old rats had significantly lower hemoglobin, hematocrit and plasma iron than middle-aged rats. This decrease in hematologic and transport iron variables was not accompanied by a shift of iron into other storage compartments. Old rats also had significantly lower total iron content and iron concentration in liver, spleen and bone marrow. Hemosiderin iron in marrow smears correlated significantly (r = 0.43-0.76, P: < 0.05) with chemical estimates of iron in storage, transport and functional pools. Old rats also tended to have less stained iron in femur marrow smears. Thus, body iron in functional, transport and storage compartments, namely the liver, spleen and bone marrow, were significantly lower in old than in middle-aged rats. Although iron stores and status are usually considered to increase with advancing age, our data show a consistent pattern of lower hematologic and storage iron variables in old than in middle-aged Lewis rats. Future research is indicated to understand the biology and functional consequences of the observed age-associated decline in body iron.

Retinoic acid and polyriboinosinic acid act synergistically to enhance the antibody response to tetanus toxoid during vitamin A deficiency: possible involvement of interleukin-2 receptor-beta, signal transducer and activator of transcription-1, and interferon regulatory factor-1.

Antibody responses to T cell-dependent antigens are reduced during vitamin A (VA) deficiency and restored by retinoids. To test whether retinoic acid (RA) and polyinosinic:polycytidylic acid (PIC), an inducer of interferons, can increase specific antibody production, VA-deficient rats were treated with all-trans-RA, PIC, or both at the time of primary immunization with tetanus toxoid. VA-deficient rats produced low primary and secondary anti-tetanus IgG responses (P<.001 vs. VA-sufficient controls). Both responses were increased synergistically by RA plus PIC (P<.0001). In VA-deficient spleens, mRNAs were low for interleukin (IL)-2 receptor-beta, interferon regulatory factor-1, and signal transducer and activator of transcription 1. Each, however, was induced by RA plus PIC (P<.0001 vs. controls). Conversely, IL-12 and IL-10 mRNAs were elevated in VA deficiency and were induced by PIC and suppressed by RA. Thus, RA plus PIC appears to be a promising combination for stimulating antigen-specific immunity. Several molecular factors identified here may partially account for the observed enhancement.

Electrochemical study of the effect of ADP and AMP on the kinetics of glutamate dehydrogenase.

A chronoamperometric method based on the 'diffusion' layer concept of the convective system was used to assay the glutamate dehydrogenase (GLDH) activity. Once the reaction was initiated by adding the enzyme GLDH into a well-stirred nicotinamide adenine dinucleotide (NADH, coenzyme) solution, the steady-state oxidation limiting current of NADH would decrease linearly in a short time. The major advantage of this method is that it directly indicates the continuous in-situ change of the coenzyme concentration, thus, the real initial reaction rate of enzyme-catalyzed reaction, V0, can be determined. Using this method, the effect of adenosine-5'-monophosphate (AMP) and adenosine-5'-diphosphate (ADP) on the GLDH activity has been monitored. The results showed that ADP and AMP could increase the activity of GLDH. This activation mechanism was proposed by the voltammetric study.

Variations in dietary iron alter brain iron metabolism in developing rats.

The rat has been widely used as a model for the study of iron deficiency (ID), but the differences in the timing of development of humans and rats must be taken into account to derive appropriate conclusions from the animal model. This study was designed to evaluate the effects of dietary ID and iron excess on rat brain iron and the iron metabolism proteins, transferrin (Tf), transferrin receptor (TfR) and ferritin. The experimental design is developmentally sensitive and permits control of the timing as well as the duration of the nutritional insult. Iron-deficient and iron-supplemented (SU) rats between postnatal day (PND) 10 and 21, PND 21 and 35 and PND 10 and 35 were used to study the effects of early, late, and long-term iron deficiency and supplementation. Some ID rats were iron repleted between PND 21 and 35. These experiments demonstrated several new findings: 1) Early ID/SU (PND 10-21) altered brain iron, TfR, Tf and ferritin concentration in many regions different from those observed in the later period (PND 21-35). 2) Two weeks of iron repletion were adequate for correcting the overall Fe concentration of the brain and of individual brain regions, although larger amounts of iron were necessary to fully normalize iron and its regulatory proteins. 3) Long-term ID/SU resulted accordingly in the continued decrease or increase in brain iron concentration in some brain regions and not others. In conclusion, brain regions regulate their iron concentration in response to local needs when faced with alterations in systemic iron delivery.

Electrochemical studies of the interaction of adriamycin to DNA.

An electrochemical investigation of the interaction of adriamycin (DXH) with DNA on a Hg electrode is reported. In weakly acidic media of pH 4.0-7.0, the addition of DNA to DXH solution results in the decrease of redox peak currents. In the presence of DNA, no new peak appears and the standard rate constant k(s) is not significantly changed. The binding of DXH to DNA by electrostatic attraction and intercalation forms a kind of supramolecular complex DXH-DNA, which is electrochemically non-active. The equilibrium constant for the complex is calculated. The decrease in peak current is proportional to DNA concentration and can be used to determine DNA concentration.

(C70)2-p-tert-butylcalix[6]arene complex films on electrodes catalyze the reduction of nitrite ions.

(C70)(2)-p-tert-butylcalix[6]arene complex films on GC electrode surface showed two couples of redox reactions in mixed solvent of (1:1, v:v) acetonitrile and water containing tetra-butylammonium perchlorate. The electrocatalytic reduction for nitrite by these films was observed, indicating that (C70)(2)-p-tert-butylcalix[6]arene is capable of mediating the electron transfer to nitrite.

Chronic marginal vitamin A status reduces natural killer cell number and function in aging Lewis rats.

Natural killer (NK) cells function in the regulation of immune responses and in the surveillance of malignant or other abnormal cells. Little is known of the effects of chronic marginal vitamin A (VA) status or VA supplementation, or their interaction with age, on NK cell number and cytolytic activity. We have conducted a two-factor (diet, age) study in which male Lewis rats were fed AIN-93M diet, modified to contain either 0.3 (designated marginal), 4.0 (control) or 50 (supplemented) mg retinol equivalents (RE)/kg diet, from the time of weaning until the ages of 2.5 mo (young), 8-10 mo (middle-aged) or 18-20 mo (old). Natural killer cells were identified and quantified in peripheral blood mononuclear cells (PBMC) and spleen with the use of flow cytometry, and NK cell cytotoxicity was assayed. The number and percentage of PBMC NK cells increased with age (P < 0.0001 by two-way ANOVA). For all age groups, values were lowest in rats with marginal VA status (P < 0.0001 vs. controls). NK cell lytic activity also declined with age (P = 0. 0003). As a result, NK cell lytic efficiency (lytic activity per NK cell) decreased markedly with age (P < 0.0001). Regardless of the donor's age or VA status, PBMC NK cell cytotoxicity doubled (100 +/- 25% increase) after exposure to interferon-alpha (5 x 10(5) U/L for 1 h before assay), indicating that IFN-stimulated lytic activity was related directly to basal NK cell activity. If the relationships observed in this animal model can be applied to humans, these data suggest that elderly people consuming diets chronically low in VA may be at increased risk for infectious or neoplastic diseases.

Electrochemical studies of NiTMpyP and interaction with DNA.

In this paper, cyclic voltammetry, linear sweep voltammetry and chronocoulometry in connection with the hang mercury drop electrode were used to study NiTMpyP and its mixture with DNA. The reduction of NiTMpyP in our experimental conditions involves in 4e reduction of TMpyP. NiTMpyP interacting with DNA forms electrochemically non-active complex DNA-2NiTMpyP, which can not be reduced on the Hg electrode. The peak potential of NiTMpyP does not shift and its electrochemical kinetic parameters indicate no significant change in the presence of DNA. However, the reduction current of NiTMpyP decreases obviously due to the formation of DNA-2NiTMpyP, which implies its equilibrium concentration decreases when DNA was mixed. The decrease of peak current is proportional to DNA concentration, which can be applied to estimate DNA concentration.

Electrocatalysis of cytochrome c at a C(60)-gamma-cyclodextrin and Nafion chemically modified electrode.

The C(60)-gamma-cyclodextrin and Nafion chemically modified electrode exhibits two redox waves by cyclic voltammetry. Such an electrode will effect reduction and oxidation of cytochrome c and be capable of mediating the electron transfer to cytochrome c.

Pulsatile and steady flow induces c-fos expression in human endothelial cells.

The effects of pulsatile and steady fluid flow on the mRNA levels of proto-oncogenes c-fos, c-jun, and c-myc in cultured human umbilical vein endothelial cells (HUVEC) were investigated. c-fos mRNA levels in stationary cultures were very low. A 1 Hz pulsatile flow with an average shear stress of 16 dynes/cm2 induced a dramatic increase of c-fos mRNA levels in HUVEC 0.5 h after the onset of flow, which declined rapidly to basal levels within 1 h. Steady flow with a similar shear stress also induced a transient increase of c-fos mRNA levels, but to a lesser extent. In addition, increased c-fos mRNA levels were observed when low shear (2-6 dynes/cm2) was replaced by high shear (16-33 dynes/cm2). Pulsatile and steady flow caused a slight increase of c-jun and c-myc mRNA levels. The role of pulsatility was also investigated in platelet-derived growth factor (PDGF) expression. Pulsatile flow induced a transient increase of PDGF A- and B-chain mRNA levels with peaks at 1.5-2 h. Pulsatile flow, which was more stimulatory in mediating c-fos expression, however, was less stimulatory than steady flow in mediating PDGF expression. By using various inhibitors, protein kinase C was found to be an important mediator in flow-induced c-fos expression, with the involvement of G proteins, phospholipase C, and intracellular calcium. Protein kinase C was previously shown as a possible major mediator in flow-induced PDGF expression which, at least partly, appeared to follow the induction mechanism of c-fos, suggesting a possible connection between c-fos and PDGF induction. However, the c-fos antisense treatment, which significantly inhibited c-fos transcription, failed to block the flow-induced PDGF expression, suggesting that flow-induced c-fos expression may not play an important role in the mechanism of flow-induced PDGF expression. The difference in the induction of c-fos and PDGF expression under pulsatile as compared to steady flow indicates that a complex, flow-mediated regulatory mechanism of gene expression exists in HUVEC. The increased expression of these proto-oncogenes mediated by flow may be important in regulating long-term cellular responses.

[Clinical and experimental study on shen-qi injection with chemotherapy in the treatment of malignant tumor of digestive tract].

Shen-Qi (Ginseng-Astragalus) injection was used with chemotherapy in the treatment of 176 cases of malignant tumor of the digestive tract. Results showed that Shen-Qi injection could reduce the toxic effects produced by chemical agents and increase the patient's body weight, as compared with that treated by chemotherapy alone (P < 0.001). It could protect the body's hematopoietic function. In Shen-Qi injection with chemotherapy group; the WBC count changed insignificantly but in chemotherapy group the WBC count reduced markedly, in which the rate of chemotherapy failure was 26.5% the difference between these two groups appeared to be significant (P < 0.01). Shen-Qi injection could increase the cellular immunologic function of the body, including phagocytic index and percentage of phagocytes, T lymphocyte transformation rate(cpm) as well as esterase stain. Further more, Shen-Qi injection could promote blood circulation to remove blood stasis and reduce the whole blood specific viscosity (P < 0.05). In the animal experiment, the total number of bone marrow cells and karyocytes of combined treatment group was found to be higher (P < 0.001) and the average weight of thymus was heavier (P < 0.05) than that in chemotherapy group. Shen-Qi injection could also prolong the survival time and increase the tumor inhibiting rate of experimental mice.

Shear-induced platelet-derived growth factor gene expression in human endothelial cells is mediated by protein kinase C.

Our previous studies have shown that steady shear stress causes a transient increase of platelet-derived growth factor (PDGF) A and B chain mRNA levels in human umbilical vein endothelial cells (HUVEC). In the present study, we elucidated the signaling pathway of shear stress in HUVEC by examining the roles of protein kineses, intracellular calcium, cyclooxygenase, and guanine nucleotide-binding proteins (G proteins) in the PDGF gene induction by shear. The protein kinase C inhibitors, H7 and staurosporine, strongly inhibited the shear-induced PDGF gene expression in HUVEC. In contrast, HA1004, a cAMP- and cGMP-dependent protein kinases inhibitor, was only slightly inhibitory. BAPTA/AM, an intracellular calcium chelator, partially (50%) inhibited the shear-induced PDGF gene expression. The cyclooxygenase inhibitors, ibuprofen and indomethacin, were slightly inhibitory. A 35-50% inhibition of shear-induced PDGF gene expression was found with GDP-beta-S, an inhibitor of G proteins. These results suggest that shear-induced PDGF gene expression in HUVEC is mainly mediated by protein kinase C activation and requires intracellular calcium. Furthermore, G proteins seem to be involved in this process, whereas prostaglandin synthesis via cyclooxygenase pathway is not. We propose a mechanism of shear-induced PDGF gene expression in HUVEC: Shear stress, either directly or indirectly (G protein-mediated), enhances the membrane phosphoinositide turnover via phospholipase C, producing diacylglycerol, an activator of protein kinase C. The activated protein kinase C then triggers the subsequent PDGF gene expression.

Shear stress increases endothelial platelet-derived growth factor mRNA levels.

We have investigated the effect of shear stress on platelet-derived growth factor (PDGF) A and B chain mRNA levels in cultured human umbilical vein endothelial cells (hUVEC). The levels of both PDGF A and B mRNA in hUVEC were increased by a physiological shear stress (16 dyn/cm2), reaching a maximum approximately 1.5-2 h after the onset of shear stress and returning almost to control values at 4 h. The peak levels showed a more than 10-fold enhancement for PDGF A mRNA and a 2- to 3-fold increase for PDGF B mRNA (P less than 0.05). PDGF A mRNA also showed a shear-dependent increase from 0 to 6 dyn/cm2 (P less than 0.05) and then plateaued from 6 to 51 dyn/cm2. PDGF B mRNA levels were elevated as shear stress increased from 0 to 6 dyn/cm2 then declined gradually to a minimum at 31 dyn/cm2 (P less than 0.05) and increased again when shear stress rose to 51 dyn/cm2 (P less than 0.05). PDGF, a potent smooth muscle cell mitogen and vasoconstrictor, released from the endothelium may regulate the blood flow in vivo. The shear stress-dependent elevation of PDGF A and B mRNA in endothelial cells may be involved in the adaptation of blood vessels to flow mediated by the endothelium.