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991.
Studies report variable factors associated with dog and cat surpluses in the United States. Estimates of cat and dog birth and death rates help understand the problem. This study collected data through a commercial survey company, distributing questionnaires to 7,399 cat- and dog-owning households (HHs) in 1996. The study used an unequal probability sampling plan and reported estimates of means and variances as weighted averages. The study used estimates of HHs and companion animals for national projections. More than 9 million owned cats and dogs died during 1996-yielding crude death rates of 8.3 cat deaths/100 cats in HHs and 7.9 dog deaths/100 dogs in HHs. The study reported twice as many kitten as puppy litters, with an average litter size of 5.73 and 7.57, respectively. The study reported data on planned versus unplanned litters, reasons caregivers did not spay females, disposition of litters, and sources of animals added to HHs. These first national estimates indicate the magnitude of, and reasons for, animals leaving HHs. The crude birth rate was estimated to be 11.2 kittens/100 cats in HHs and 11.4 puppies/100 dogs in HHs.  相似文献   
992.
Hyperthermia (HT) in combination with anticancer drugs (ACDs) had proven to more efficacious in various cancers, although efficacies vary according to chemotherapeutic compounds and cancer types. Presently there are few data that compares anticancer efficacies among ACDs under hyperthermic conditions. Therefore, we selected three commonly used ACDs (quercetin, verapamil and doxorubicin) and compared their antitumor effects when each was treated with 43°C HT exposure. Firstly, FM3A, a murine breast cancer cell line, was treated with each ACD for 1 h followed by 43°C exposure for additional 1 h, and examined the effects of: 1) each drug, 2) 43°C HT exposure, and 3) the combination of each drug and 43°C HT exposure for 1, 6 and 24 h. The determined overall effects on FM3A cells were arrested cell proliferation, clonogenic efficiency and apoptosis. Pre-treatment of FM3A cells to each ACD followed by 43°C HT exposure produced greater antitumor effects including suppressed cell proliferation, reduced clonogenic efficiency and increased apoptotic cell death, compared to ACD treatment or HT exposure alone. Apoptotic cell death occurred in a time-dependent manner. Among the ACDs, antitumor efficacies varied in the order of doxorubicin > verapamil > quercetin. It was concluded that heat exposure during ACD treatment of caner cells may be an important factor to get a better antitumor benefit, even though this benefit may differ from one drug to another.  相似文献   
993.
994.
We aimed to assess the effect of ovariectomy on cartilage turnover and degradation, to evaluate whether ovariectomized (OVX) rats could form an experimental model of postmenopausal osteoarthritis. The effect of ovariectomy on cartilage was studied using two cohorts of female Sprague–Dawley rats, aged 5 and 7 months. In a third cohort, the effect of exogenous estrogen and a selective estrogen receptor modulator was analyzed. Knee joints were assessed by histological analysis of the articular cartilage after 9 weeks. Cartilage turnover was measured in urine by an immunoassay specific for collagen type II degradation products (CTX-II), and bone resorption was quantified in serum using an assay for bone collagen type I fragments (CTX-I). Surface erosion in the cartilage of the knee was more severe in OVX rats than in sham-operated animals, particularly in the 7-month-old cohort (P = 0.008). Ovariectomy also significant increased CTX-I and CTX-II. Both the absolute levels of CTX-II and the relative changes from baseline seen at week 4 correlated strongly with the severity of cartilage surface erosion at termination (r = 0.74, P < 0.01). Both estrogen and the selective estrogen receptor modulator inhibited the ovariectomy-induced acceleration of cartilage and bone turnover and significantly suppressed cartilage degradation and erosion seen in vehicle-treated OVX rats. The study indicates that estrogen deficiency accelerates cartilage turnover and increases cartilage surface erosion. OVX rats provide a useful experimental model for the evaluation of the chondroprotective effects of estrogens and estrogen-like substances and the model may be an in vivo representation of osteoarthritis in postmenopausal women.  相似文献   
995.
Yang LL  Liang YC  Chang CW  Lee WS  Kuo CT  Wang CC  Lee HM  Lin CH 《Life sciences》2002,72(2):199-213
Recently, under large-scale screening experiments, we found that sphondin, a furanocoumarin derivative isolated from Heracleum laciniatum, possessed an inhibitory effect on IL-1beta-induced increase in the level of COX-2 protein and PGE(2) release in A549 cells. Accordingly, we examined in the present study the action mechanism of sphondin on the inhibition of IL-1beta-induced COX-2 protein expression and PGE(2) release in a human pulmonary epithelial cell line (A549). Pretreatment of cells with sphondin (10-50 microM) concentration-dependently attenuated IL-1beta-induced COX-2 protein expression and PGE(2) release. The IL-1beta-induced increase in COX-2 mRNA expression was also attenuated by sphondin (50 microM). The selective COX-2 inhibitor, NS-398 (0.01-1 microM), inhibited the activity of the COX-2 enzyme in a concentration-dependent manner, while sphondin (10-50 microM) had no effect. Sphondin (50 microM) did not affect the IL-1beta-induced activations of p44/42 MAPK, p38 MAPK, and JNK. Treatment of cells with sphondin (50 microM) or the NF-kappaB inhibitor, PDTC (50 microM) partially inhibited IL-1beta-induced degradation of IkappaB-alpha in the cytosol and translocation of p65 NF-kappaB from the cytosol to the nucleus. Furthermore, IL-1beta-induced NF-kappaB-specific DNA-protein complex formation in the nucleus was partially inhibited by sphondin (50 microM) or PDTC (50 microM). Taken together, we demonstrate that sphondin inhibits IL-1beta-induced PGE(2) release in A549 cells; this inhibition is mediated by suppressing of COX-2 expression, rather than by inhibiting COX-2 enzyme activity. The inhibitory mechanism of sphondin on IL-1beta-induced COX-2 expression may be, at least in part, through suppression of NF-kappaB activity. We conclude that sphondin may have the therapeutic potential as an anti-inflammatory drug on airway inflammation.  相似文献   
996.
The major growth seen in the biotechnology industry in recent decades has largely been driven by the exploitation of genetic engineering techniques. The initial benefits have been predominantly in the biomedical area, with products such as vaccines and hormones that have received broad public approval. In the environmental biotechnology and industrial ecology sectors, biotechnology has the potential to make significant advances through the use of genetically modified (GM) microbial inoculants that can reduce agri-chemical usage or remediate polluted environments. Although many GM inoculants have been developed and tested under laboratory conditions, commercial exploitation has lagged behind. Here, we review scientific and regulatory requirements that must be satisfied as part of that exploitation process. Particular attention is paid to new European Union (EU) regulations (Directives) that govern the testing and release of genetically modified organisms and microbial plant protection inoculants in the EU. With regard to the release of GM inoculants, the impact of the inoculant and the fate of modified genes are important concerns. Long term monitoring of release sites is necessary to address these issues. Data are reported from the monitoring of a site 6 years after release of GM Sinorhizobium meliloti strains. It was found that despite the absence of a host plant, the GM strains persisted in the soil for at least 6 years. Horizontal transfer and microevolution of a GM plasmid between S. meliloti strains was also observed. These data illustrate the importance of assessing the long-term persistence of GM inoculants. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   
997.
Genetic mutations of theCl channel ClC-5 cause Dent's disease in humans. Werecently cloned an amphibian ortholog of Xenopus ClC-5(xClC-5) from the A6 cell line. We now compare the properties and regulation of ClC-5 currents expressed in mammalian (COS-7) cellsand Xenopus oocytes. Whole cell currents in COS-7 cells transfected with xClC-5 cDNA had strong outward rectification, Cl > I anion sensitivity, and wereinhibited at low pH, similar to previous results in oocytes. Inoocytes, antisense xClC-5 cRNA injection had no effect on endogenousmembrane currents or the heterologous expression of human ClC-5.Activators of cAMP and protein kinase C inhibitors had nosignificant effects on ClC-5 currents expressed in either COS-7 cellsor oocytes, whereas H-89, a cAMP-dependent protein kinase (PKA)inhibitor, and hydrogen peroxide decreased the currents. We concludethat the basic properties of ClC-5 currents were independent of thehost cell type used for expression. In addition, ClC-5 channels may bemodulated by PKA and reactive oxygen species.

  相似文献   
998.
AIMS: To assess the effects of soil type and time of the year on survival of the biocontrol inoculant Pseudomonas fluorescens CHA0 under aerobic conditions in lysimeter effluent water. METHODS AND RESULTS: Effluent water was collected at different times from large outdoor lysimeters (2.5 m deep), which contained a well-drained or a poorly-drained cambisol, and inoculated with CHA0. The inoculant was monitored for 175 d by colony counts, total immunofluorescence cell counts and Kogure's viable cell counts. Cell numbers obtained with the three methods were similar. The inoculant declined exponentially in time and its population level varied considerably depending on the time of the year at which effluent water had been collected and soil type in the lysimeter. Positive correlations were found between the number of resident culturable aerobic bacteria and subsequent survival of the inoculant. CONCLUSION: The fluctuations of inoculant survival patterns correlated with differences in biological properties of lysimeter water that were related to soil type and time of the year. SIGNIFICANCE AND IMPACT OF THE STUDY: Results suggest that predictability of the survival of bacterial soil inoculants transported to groundwater level by heavy rainfall may be improved by taking into account key biological properties of the water.  相似文献   
999.
Mo Y  Nishinari K 《Biorheology》2001,38(5-6):379-387
The extensional viscosity and the steady shear viscosity of sodium type hyaluronan (NaHA) in water with sodium chloride and/or sucrose and in DMSO solvent were measured. The extensional viscosities for HA in aqueous solution (0.05, 0.1, 0.3 w/v%) were constant at lower extensional rates, and then became strain thinning above a critical extensional rate. However, on adding sodium chloride, the extensional viscosity decreased and became strain thickening at higher extensional rates. Sodium ions shield the electrostatic repulsion between carboxyl residues of HA molecules and constrict the coil dimensions. The strain thickening of HA solution in the presence of sodium chloride at higher extension rates is due to the coil stretching. The addition of sucrose increased the extensional viscosity and shifted the critical extensional rate to lower strain rates. With increasing strain (shear) rates, extensional (shear) viscosities for HA aqueous solutions remained constant up to a critical extension (shear) rate; but they showed no plateau and decreased linearly in DMSO. It is clear that molecular interaction of HA in DMSO is stronger than that in aqueous solution. This should be attributed to the different conformations of HA in DMSO and in aqueous solutions.  相似文献   
1000.
Site-directed mutagenesis, electron microscopy, and X-ray crystallography were used to probe the structural basis of annexin IV-induced membrane aggregation and the inhibition of this property by protein kinase C phosphorylation. Site-directed mutants that either mimic (Thr6Asp, T6D) or prevent (Thr6Ala, T6A) phosphorylation of threonine 6 were produced for these studies and compared with wild-type annexin IV. In vitro assays showed that unmodified wild-type annexin IV and the T6A mutant, but not PKC-phosphorylated wild-type or the T6D mutant, promote vesicle aggregation. Electron crystallographic data of wild-type and T6D annexin IV revealed that, similar to annexin V, the annexin IV proteins form 2D trimer-based ordered arrays on phospholipid monolayers. Cryo-electron microscopic images of junctions formed between lipid vesicles in the presence of wild-type annexin IV indicated a separation distance corresponding to the thickness of two layers of membrane-bound annexin IV. In this orientation, a single layer of WT annexin IV, attached to the outer leaflet of one vesicle, would undergo face-to-face self-association with the annexin layer of a second vesicle. The 2.0-A resolution crystal structure of the T6D mutant showed that the mutation causes release of the N-terminal tail from the protein core. This change would preclude the face-to-face annexin self-association required to aggregate vesicles. The data suggest that reversible complex formation through phosphorylation and dephosphorylation could occur in vivo and play a role in the regulation of vesicle trafficking following changes in physiological states.  相似文献   
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