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931.
We performed an experiment with 112 piglets, 32 growing-finishing pigs, and 12 sows during pregnancy and lactation to test the hypotheses that apparent total tract digestibilities of P and Ca as well as the efficacy of Aspergillus niger phytase in rendering phytate P available in pigs depend on pig physiological status. All pigs were fed diets with identical feedstuff composition either without or with added microbial phytase (Natuphos, 500 FTU/kg diet). The diets contained 6.2 g Ca, 4.8 g total P, and 3.7 g phytate P per kilogram, and intrinsic phytase activity of 120 FTU/kg. The digestibility of P increased by 8.3 percentage units when BW of pigs increased from 30 to 60 kg and then remained stable until 100 kg. Pregnant sows had a lower efficiency of P absorption than piglets and growing-finishing pigs. During lactation, the efficiency of P absorption was 3.4 percentage units higher than during pregnancy but was still 6.6 percentage units lower than for growing-finishing pigs. The efficacy of the phytase in generating digestible P decreased in the order or lactating sows, growing-finishing pigs, sows at the end of pregnancy, piglets, and sows at midpregnancy; the average amounts of generated digestible P were 1.03, .83, .74, .66, and .32 g/kg diet, respectively. The addition of phytase to the diet raised apparent Ca digestibility in the piglets and growing-finishing pigs (by 4.6 and 4.0 percentage units, respectively) but not in the sows. We conclude that in the formulation of swine diets the amount of phytase to be added should be tailored to the target category. 相似文献
932.
Using a tensiometer in accordance with the drop volume principle, the surface tension decrease with time was determined for whole and for 2%, 10%, and 50% aqueous solutions of saliva from one healthy donor. The reduction of surface tension with time was also measured for 10% and 20% saliva solutions with added samples of Streptococcus salivarius KRF2, S. sanguis KRF3, and Actinomyces naeslundii 2t-55. The results show that 1) there is a time dependence of the surface tension reduction of both whole saliva and diluted saliva, 2) an increase of the concentration of whole saliva in salivary solutions gives rise to larger and more rapid surface tension reduction, 3) the proteinaceous components of saliva appear to have a dominant contribution on surface tension in whole saliva and diluted saliva, and 4) the surface-active proteinaceous components in saliva have the ability to dominate the air-saliva interface also in the presence of high concentrations of salivary bacteria. 相似文献
933.
GF Greene Y Kitadai CA Pettaway AC von Eschenbach CD Bucana IJ Fidler 《Canadian Metallurgical Quarterly》1997,150(5):1571-1582
934.
935.
AC Horsfall DM Butler L Marinova PJ Warden RO Williams RN Maini M Feldmann 《Canadian Metallurgical Quarterly》1997,159(11):5687-5696
The onset of collagen-induced arthritis in DBA/1 mice is accompanied by a predominantly Th1 response, characterized by production of the proinflammatory cytokines IFN-gamma and TNF-alpha, and a predominance of IgG2a anti-collagen Abs. This study has primarily addressed the effects of continuous administration of exogenous IL-4, a Th2 cytokine, on collagen-induced arthritis in terms of time of onset, clinical symptoms, and histologic changes compared with those in untreated controls. The contributions of Th1 and Th2 cell responses were studied by examining anti-CII IgG subclasses, serum IgE levels, and cytokine production by synovial membrane and lymph node cell cultures. Continuous exposure to IL-4 for 28 days significantly delayed the onset of arthritis from 19 to 37 days and suppressed clinical symptoms. Arthritis occurred approximately 13 to 24 days after treatment ceased. Thereafter, the severity and duration of clinical symptoms were similar to those in control animals, although both joint damage and inflammation at the histologic and cellular levels were less severe than those in untreated controls. During IL-4 treatment, anti-collagen Ab levels were reduced (most significantly those of the IgG2a subclass), histology scores were lower, and the most striking effect was a 1000-fold decrease in TNF-alpha secretion by synovial cells. No significant differences in IgE levels were found between controls and IL-4-treated mice. These data suggest that the anti-inflammatory properties of IL-4 are mediated in part by down-regulation of Th1 responses rather than up-regulation of Th2 responses. 相似文献
936.
AC Tsamandas R Shapiro M Jordan AJ Demetris PS Randhawa 《Canadian Metallurgical Quarterly》1997,11(2):139-141
PURPOSE: To investigate the diagnostic accuracy of faecal occult blood test (FOBT) for anal diseases and to evaluate the relationship of this disorder to the results of FOBT. METHODS: In a hospital-based retrospective study, FOBT using faecal samples collected on two consecutive days was performed on patients with anal disease, such as internal as well as external haemorrhoids and anal fissure, patients with colorectal cancer and healthy subjects to evaluate the diagnostic accuracy of FOBT. In a screening-programme-based cross-sectional study, the subjects who underwent colorectal cancer screening by FOBT using the 2-day method were divided into two groups according to the results of a questionnaire on anal diseases; the positive rate of FOBT as well as the predictive value for colorectal cancer were determined in the two groups. RESULTS: Among 300 cases, including 100 anal diseases, 100 colorectal cancers and 100 healthy subjects, the test was positive in 12 anal diseases, 82 colorectal cancers and six healthy subjects. The sensitivity to anal diseases and colorectal cancer was calculated to be 12% and 82%, respectively, and the specificity was 95%. A significant difference was noted in the sensitivity between anal diseases and colorectal cancer (P < 0.001). Among 21,724 subjects, who underwent colorectal cancer screening, 2395 subjects were positive for anal diseases, and 19,329 subjects were negative. The positive rate of FOBT was 7.2 for the anal diseases group and 6.8 for the non-anal diseases group, and the predictive value for colorectal cancer was 2.9 and 3.0, indicating no substantial difference between the two groups. CONCLUSIONS: These results reveal that FOBT is inferior for the diagnosis of anal diseases, and anal diseases have little relationship to the results of FOBT. 相似文献
937.
938.
TB Kinney SC Rose KE Weingarten K Valji SB Oglevie AC Roberts 《Canadian Metallurgical Quarterly》1997,8(6):1029-1037
PURPOSE: A comparison of tilting, caval coverage, asymmetry, and insertion problems with the over-the-wire stainless-steel and titanium versions of the Greenfield filter. MATERIALS AND METHODS: The study compared 104 stainless-steel and 141 titanium Greenfield inferior vena cava (IVC) filter insertions. The angle the sheath and deployed filter made relative to the cava, as well as filter strut distribution, were determined from spot films. The proportionate caval coverage was computed from the cavogram (anteroposterior projection). Mean filter tilts, subgrouped by insertion site, and caval coverage were compared with the Student t test, whereas strut patterns were analyzed with a contingency table. RESULTS: The filter caval and sheath caval angles correlated. The filter caval angles varied with insertion site, but were lowest with a right jugular approach. Caval coverage was identical with both designs. The stainless-steel version resulted in a more uniform distribution of struts in comparison with the titanium version. The incidence of insertion problems was not significantly different between the filter types. CONCLUSIONS: While IVC filter tilting was not improved with the newer design, the pattern of struts was more uniformly symmetric with the stainless-steel device. The right jugular insertion site was associated with the lowest filter caval angles and the most symmetric pattern of struts. 相似文献
939.
940.
FJ Moy M Safran AP Seddon D Kitchen P B?hlen D Aviezer A Yayon R Powers 《Canadian Metallurgical Quarterly》1997,36(16):4782-4791
Interaction of basic fibroblast growth factor (FGF-2) with heparin or heparan sulfate proteoglycans (HSPGs) is required for receptor activation and initiation of biological responses. To gain insight into the mechanism of activation of the FGF receptor by FGF-2 and heparin, we have used NMR, dynamic light scattering, and HSPG-deficient cells and cell-free systems. The first 28 N-terminal residues in FGF-2 were found to be highly mobile and flexible, consistent with the disorder found in both the NMR and X-ray structures. The structure of an FGF-2-heparin-decasaccharide complex that binds to and activates the FGF receptor was compared to a heparin-tetrasaccharide-induced complex that does not promote an interaction with the receptor. The major change observed upon the addition of the tetrasaccharide to FGF-2 was an increase in the correlation time consistent with the formation of an FGF-2 dimer. The NMR line widths of FGF-2 in the presence of the decasaccharide are severely broadened relative to the tetrasaccharide, consistent with dynamic light scattering results which indicate FGF-2 is a tetramer. The interaction of these heparin species with FGF-2 does not induce a significant conformational change in the overall structure of FGF-2, but small chemical shift changes are observed in both heparin and receptor binding sites. A trans-oriented symmetric dimer of FGF-2 is formed in the presence of the tetrasaccharide whereas two cis-oriented dimers in a symmetric tetramer are formed in the presence of the decasaccharide. This suggests that the cis-oriented FGF-2 dimer is the minimal biologically active structural unit of FGF-2. These data allow us to propose a novel mechanism to explain the functional interaction of FGF-2 with heparin and its transmembrane receptor. 相似文献