共查询到20条相似文献,搜索用时 12 毫秒
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JA Winkles GF Alberts M Chedid WG Taylor S DeMartino JS Rubin 《Canadian Metallurgical Quarterly》1997,173(3):380-386
The objective of this study was to analyze the efficacy and correlation between clinical and histologic parameters used to evaluate oral implants. After extraction of the premolars and a healing time of 4 months in 16 Dutch goats, four Br?nemark implants were placed in the maxillary left and right premolar regions. After a healing time of 6 months, followed by another 4 months with the permucosal abutments, the goats were sacrificed and the jaws were block-resected. Before histologic preparation, long-cone radiographs were made and Periotest scores of the implants were recorded. Bone level measured histomorphometrically were found to be 0.85 mm more apically, compared to that measured radiologically (P = .001). Furthermore, statistically significant correlations (P > 0.2) were not found between the Periotest values of the calcium-phosphate-coated and uncoated implants for (1) the first thread in contact with bone, or (2) with the total number of threads in contact with bone. It was concluded that the radiologic data overscored the real marginal bone level around screw-shaped oral implants, and that the Periotest device is neither able to discriminate between the first thread nor between the total number of threads in contact with bone. 相似文献
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This study examined the mitogenic response to keratinocyte growth factor (KGF) of normal and tumour-derived human oral keratinocytes in which the degree of cellular differentiation was known and in contiguous fibroblast cultures derived from the malignant epithelial cultures. Keratinocytes, but not fibroblasts, were stimulated by KGF, thereby demonstrating epithelial target cell specificity of the ligand. KGF-induced stimulation of the tumour-derived keratinocytes cultured in the absence of the 3T3 fibroblast support broadly correlated with the degree of cellular differentiation; well-differentiated keratinocytes were stimulated more by KGF than their less differentiated counterparts. Malignant oral keratinocytes expressed KGF cell surface receptors (KD 451-709 pM; receptors/cell 2306-13645), but KGF receptor mRNA did not correlate with either KGF-induced mitogenesis or the degree of epithelial cell differentiation. When the tumour-derived keratinocytes were cultured in the presence of 3T3 fibroblasts, the mitogenic response to KGF was comparable to normal epithelial cells. The results suggest that KGF-mediated growth stimulation may not be significant in providing a selective advantage for the growth of malignant keratinocytes. 相似文献
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Characterization of recombinant human fibroblast growth factor (FGF)-10 reveals functional similarities with keratinocyte growth factor (FGF-7) 总被引:1,自引:0,他引:1
A newly identified member of the fibroblast growth factor (FGF) family, designated FGF-10, is expressed during development and preferentially in adult lung. The predicted FGF-10 protein is most related to keratinocyte growth factor (KGF, or FGF-7). The latter is unique among FGFs in that it binds and signals only through the FGF receptor (FGFR2b) isoform KGF receptor (KGFR) expressed specifically by epithelial cells. In order to examine the biological and biochemical properties of human FGF-10, we isolated the cDNA and expressed its encoded protein in bacteria. The recombinant protein (rFGF-10) was a potent mitogen for Balb/MK mouse epidermal keratinocytes with activity detectable at 0.1 nM and maximal at around 5 nM. Within this concentration range, FGF-10 did not stimulate DNA synthesis in NIH/3T3 mouse fibroblasts. rFGF-10 bound the KGFR with high affinity comparable to that of KGF, and did not bind detectably to either the FGFR1c (Flg) or FGFR2c (Bek) receptor isoforms. The mitogenic activity of FGF-10 could be distinguished from that of KGF by its different sensitivity to heparin and lack of neutralization by a KGF monoclonal antibody. These results indicate that FGF-10 and KGF have similar receptor binding properties and target cell specificities, but are differentially regulated by components of the extracellular matrix. 相似文献
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Y Maeyama 《Canadian Metallurgical Quarterly》1995,42(4):291-297
Intravenous heparin followed by oral warfarin sodium is effective for preventing recurrent thromboembolism in patients who have pulmonary embolism or proximal vein thrombosis. The effectiveness of intravenous heparin depends on obtaining an adequate anticoagulant response early during therapy. A validated heparin protocol should be used to ensure that an adequate anticoagulant response is obtained as soon as possible. Low molecular weight heparin has the practical advantage that it does not require monitoring and dose finding. If thrombolytic therapy is indicated, it is safer for many patients to base management on the noninvasive diagnosis rather than performing pulmonary angiography. In patients suspected to have pulmonary embolism who have nondiagnostic lung scan and adequate cardiorespiratory reserve, serial noninvasive leg testing is a practical approach that avoids pulmonary angiography, identifies patients who have proximal vein thrombosis requiring treatment, and avoids the risks of anticoagulant treatment in the majority of patients. 相似文献
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PURPOSE: Fast SE (FSE) sequences have largely replaced conventional SE (CSE) T2-weighted sequences in the brain and have been generally accepted as qualitatively comparable. The purpose of the present study was to subject these sequences to a quantitative comparative analysis in the brain. METHOD: A quantitative analysis of relative signal intensities of white and gray matter was performed comparing CSE and FSE T2-weighted sequences in brains of 20 children at varying stages of myelination. RESULTS AND CONCLUSION: At all ages in individual patients, white matter had less signal intensity (SI) relative to gray matter on FSE than CSE, though the relative difference in SI was small. This resulted in white matter appearing slightly more myelinated on FSE than CSE. This difference is attributed to differences in magnetization transfer. In myelinated brain (white matter hypointense to gray matter), contrast-to-noise was greater with FSE, while in unmyelinated brain, contrast-to-noise was greater with CSE. 相似文献
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Expression of hepatocyte growth factor (HGF) and HGF receptor (HGFR, product of the met proto-oncogene) mRNA were examined by nonisotopic in situ hybridization in a spectrum of benign and malignant human breast tissues. mRNA for both HGFR and HGF was detected in benign ductal epithelium. Epithelial expression of HGF mRNA was particularly intense in regions of ductal epithelial hyperplasia. Positive expression of HGF (but not HGFR) mRNA was also found in adipocytes, endothelial cells, and to varying degrees in stromal fibroblasts. In 12 of 12 cases of ductal carcinoma in situ and infiltrating ductal carcinoma, carcinoma cells showed a heterogeneous pattern of expression for both HGFR and HGF mRNA. In infiltrating ductal carcinomas, intense expression of HGFR mRNA was not restricted to ductular structures but as also seen in non-duct-forming carcinoma cells. The same zones of the tumors (most commonly at the advancing margins) that expressed strongly HGFR mRNA often were also strongly positive for HGF mRNA, suggesting a possible autocrine effect. The expression pattern of HGFR protein in 25 cases including the same series of tissues used for in situ hybridization analysis was similar to that of HGFR mRNA, as determined by an immunoperoxidase technique. The finding that HGFR is expressed by both benign and malignant epithelium, and its not restricted to duct-forming structures, suggests that, although the potential for HGF/HGFR binding is maintained in malignancy, the response to ligand binding at the level of the receptor or the cellular response to receptor activation may change at some point during progression. 相似文献
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H Canatan WY Chang Y Sugimoto F Shidaifat SK Kulp RW Brueggemeier YC Lin 《Canadian Metallurgical Quarterly》1996,15(3):247-254
BACKGROUND: Recent studies have demonstrated the usefulness of gene-modified tumor cells for immunotherapy. Using the tumorigenic murine fibrosarcoma, MCA 106, we investigated the effects of localized interferon-gamma (IFNg) secretion on tumorigenicity and on long-term memory. METHODS: The murine IFNg (MuIFNg) gene was introduced into tumor cells. High and low IFNg-secreting clones were isolated. C57BL/6 mice were injected subcutaneously (s.c.) with either parental (P), high or low IFNg-secreting (H- or L-IFNg) cells, and tumor growth was assessed weekly. Spleens were harvested on different days postinjection (p.i.) to assess in vitro cytolytic activity. In parallel, tissues from injection sites were stained with macrophage-, CD4-, and CD8-detecting antibodies. Mice were injected s.c. with H-IFNg MCA106 tumor. After 150 days the animals were rechallenged s.c. with MCA106P in one leg and with irrelevant syngeneic tumor in the other. RESULTS: Both P- and L-IFNg cells had similar growth, whereas the H-IFNg cells never grew. Only splenocytes from the H-IFNg animals showed in vitro CTL activity persisting until day 30 p.i. Histological data revealed a macrophage and CD4+ infiltrate much earlier in the H-IFNg group compared with the P group. Only the irrelevant, syngeneic tumor grew in animals previously injected with H-IFNg cells, whereas both P and irrelevant syngeneic tumors grew in controls. CONCLUSIONS: Transduction of MCA106 cells with the MuIFNg gene diminished in vivo tumorigenicity in proportion to the amount of IFNg secreted. Immunization with H-IFNg cells elicited a host response characterized by macrophages and CD4+ cells. Long-term tumor-specific memory was seen after immunization with H-IFNg cells. 相似文献
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Conditioned taste aversion is a common classic conditioning procedure used to identify noxious stimuli. When a rat is given a taste solution, the conditioned stimulus (CS), followed by an unpleasant experience, the unconditioned stimulus (US), the rat will avoid consumption of the CS in future presentations. These experiments use the taste aversion procedure to examine the effect of exposure to a high magnetic field. A solution consisting of 3.0 g glucose and 1.25 g saccharin per 1 L of solution (G+S) was used as the CS and a 9.4-T magnet served as the US. In Experiment 1, all rats received a 10 min presentation of the G+S solution followed by either a 30 min exposure to the magnetic field (Magnet, n = 8), a 30-min exposure in a container with similar conditions but lacking the magnetic field (Sham, n = 8), or no exposure (Control, n = 8). The Magnet Group showed a taste aversion on the first day of preference testing (p < 0.05). Experiment 2 employed the same US-CS protocol for 3 consecutive days of conditioning. The Magnet Group demonstrated a taste aversion for the postexposure Days 1-8 (p < 0.01). There was no difference between the Sham and Control Groups in either experiment. The results of this study clearly demonstrate that the rats associated the G+S solution with the experience of being exposed to the high magnetic field and avoided the solution in subsequent presentations. 相似文献
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There is high current interest in developing synthetic routes to oligosaccharides involved in glycoconjugates. Significant attention has been focused on the application of glycosidase-catalyzed transglycosylation for practical synthesis of oligosaccharides. The enzymatic synthesis has become more practical by the use of several glycosidases available in sufficient quantities. This review describes convenient syntheses of di- and trisaccharide units, which are related to molecular recognition, by using regioselective transgalactosylation, trans-N-acetylglucosaminylation, transfucosylation, and transmannosylation. The regioselectivity could be controlled to some extent by using the following techniques: (1) varying enzymes, (2) organic co-solvent system, (3) the configuration of the existing glycosidic linkage of the acceptor and (4) inclusion complex of acceptor glycoside with cyclodextrin. Furthermore, glycopolymers carrying a series of disaccharides containing beta-D-galactosyl residues were synthesized and used as a model in oligosaccharide-lectin interaction analysis. These water-soluble glycopolymers were shown to be useful as probes of carbohydrate recognition. 相似文献
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BACKGROUND/AIMS: Forty-two patients with the diagnosis of acute hepatitis C virus hepatitis were studied to investigate the relationship between hepatitis C virus genotype and progression to chronic infection. METHODS: The patients were followed for more than 1 year (mean age 29 years, male/female ratio 2.5). Intravenous drug use was documented in 15 cases, blood transfusion in four, surgical intervention, dental therapy or other parenteral exposure in 15, and unknown factors in the remaining eight. The evolution to chronicity was diagnosed on the basis of a persistent increase in transaminase levels, the presence of HCV-RNA and the histological pattern of chronic hepatitis. RESULTS: The majority of cases presented hepatitis C virus infection of subtype 1a (38.1%) or 1b (33.9%). Six cases showed the presence of genotype 3a (14.3%). Subtype 2c was observed in three out of four cases infected with genotype 2. No significant association was demonstrated with documented risk factors. The overall chronicity rate was 59.5%. This value increased to 92% in individuals infected with genotype 1b. By multivariate analysis the age-adjusted odds ratio for infection with genotype 1b as compared with all other genotypes was 14.4 (95% confidence interval; 1.52-137). Moreover, significant differences (p= 0.0002) were present in this group for histological activity index (8.7 as compared with 5-7). CONCLUSIONS: The results of this prospective study are consistent with an independent association between hepatitis C virus genotype 1b and a poor prognosis. 相似文献
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MS Kobrin Y Yamanaka H Friess ME Lopez M Korc 《Canadian Metallurgical Quarterly》1993,53(20):4741-4744
Acidic and basic fibroblast growth factors are mitogenic polypeptides that are overexpressed in pancreatic cancer. To determine whether fibroblast growth factors may exert direct effects on pancreatic cancer cells in vivo, we compared the expression of the high-affinity type I fibroblast growth factor receptor (FGFR-1) in human pancreatic tissues. In the normal pancreas, FGFR-1 immunostaining was seen mainly in acinar cells. In pancreatic cancers, FGFR-1 was abundant in ductal-like cancer cells which also exhibited many FGFR-1 mRNA in situ hybridization grains. Analysis by the polymerase chain reaction and RNase protection revealed that the 2-immunoglobulin-like and the 3-immunoglobulin-like forms of FGFR-1 were expressed in all tissue samples, and that the 2-immunoglobulin-like form was overexpressed in the cancer tissues by comparison with the normal tissues. These findings suggest that the 2-immunoglobulin-like form of FGFR-1 may contribute to aberrant autocrine and paracrine pathways in pancreatic cancer. 相似文献
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J Malejczyk M Malejczyk F Breitburd S Majewski A Schwarz N Expert-Besan?on S Jablonska G Orth TA Luger 《Canadian Metallurgical Quarterly》1996,74(2):234-239
Analysis of conditioned media generated by weakly and highly tumorigenic SKv-1 keratinocyte lines harbouring integrated human papillomavirus type 16 (HPV16) DNA sequences revealed a factor inhibiting TNF-alpha and TNF-beta cytotoxic activity. This inhibitory activity was specifically blocked by htr-9 monoclonal antibody (MAb) recognising 55/60 kDa type I TNF receptor suggesting that it is related to a soluble form of this particular receptor (sTNF-RI). The presence of sTNF-RI was confirmed by Western blot analysis of SKv-1 cell-conditioned medium showing a band of 31.5 kDa as well as by the specific enzyme-linked immunobiological assay (ELIBA). Release of sTNF-RI was a result of shedding because Northern blot analysis showed that SKv-1 cells expressed a full-length TNF-RI mRNA, and radioimmunoprecipitation of TNF-RI from [32S]cysteine-labelled cell extracts demonstrated the presence of normal 55 kDa molecule. Evaluation by ELIBA showed that highly tumorigenic SKv-12 cells released significantly more sTNF-RI than their weakly tumorigenic SKv-11 parental cells. Furthermore, human recombinant as well as SKv cell-derived sTNF-RI stimulated proliferation of weakly tumorigenic SKv-11 cells. This suggests that a progressive growth of some neoplastic cells may be, at least partially, a result of an increased spontaneous release of sTNF-RI that enables the cells to escape from local TNF-alpha-mediated growth inhibition. 相似文献
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J Viac C Goujon L Misery V Staniek M Faure D Schmitt A Claudy 《Canadian Metallurgical Quarterly》1997,13(3):103-108
OBJECTIVE: To determine the relative efficacy and morbidity of Ho:YAG versus Nd:YAG laser treatment of bullous lung disease in an animal model. SUMMARY BACKGROUND DATA: Laser coagulation procedures for treatment of emphysematous pulmonary bullae and heterogeneous emphysema continue to evolve. The role of lasers in lung volume reduction surgery remains controversial due to issues of relative efficacy and morbidity. The Nd:YAG laser is most commonly used for these procedures. We hypothesized that the shallower penetration of the Ho:YAG laser may be better suited for laser bullae coagulation and emphysema lung volume reduction with increased efficacy and reduced lung injury. METHODS: Thirty New Zealand White rabbits (15 normal rabbits; 15 with bullous lung disease) were evaluated with Ho:YAG compared to Nd:YAG laser exposures. Bullae were coagulated by either Ho:YAG or Nd:YAG treatment. In all animals (bullous-induced and normals), unaffected lung tissue in the upper lobes and contralateral lungs were treated with 5 spot exposures of Nd:YAG and Ho:YAG, each to assess depth of lung injury. Animals were sacrificed at Days 0, 7, and 21 and their lungs were examined histologically. RESULTS: Ho:YAG and Nd:YAG exposures caused equivalent lung injury to normal lung tissue. In the acute phase, parenchymal necrosis depth was similar for both Ho:YAG and Nd:YAG (850 +/- 273 microns vs. 900 +/- 270 microns respectively, p = 0.7). By Day 7, lung necrosis depth was 925 +/- 133 microns Ho:YAG vs. 1225 +/- 235 microns Nd:YAG (p = 0.33), and lung fibrosis depth was 300 +/- 134 microns Ho:YAG vs. 558 +/- 127 microns Nd:YAG (p = 0.11). By Day 21, pulmonary parenchymal necrosis was not seen. Pleural fibrosis depth was maximal at Day 21, reaching 250 +/- 102 microns for Ho:YAG vs. 300 +/- 156 microns Nd:YAG (P = 0.88). Pleural necrosis depth was 67 +/- 42 microns Ho:YAG vs 48 +/- 34 microns Nd:YAG (p = 0.42) on Day 7 and resolved by Day 21. During surgical coagulation procedures, the Ho:YAG laser was dramatically more efficient in coagulating bullae. The Ho:YAG laser required less exposure at equivalent power and resulted in immediate desiccation of bullae, in sharp contrast to the Nd:YAG laser. CONCLUSIONS: Because the Ho:YAG was more effective and did not result in more acute lung injury than the standard Nd:YAG laser in this study, Ho:YAG lasers may have improved potential for laser treatment of bullae or lung volume reduction surgery (LVRS) compared to Nd:YAG lasers. 相似文献
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A thermal threshold measurer (TTM) apparatus was developed and tested in 12 dry, nonpregnant, culled cows with the purpose of measuring the thermal nociceptive threshold and of finding the response to morphine sulphate dosages. The cows received a cumulative dose (from 0.00 to 0.40 mg/kg BW) of morphine sulphate through a catheter in the jugular vein. The interval between doses was 20 min, and a nociceptive test was performed 15 min after each injection. The TTM device consisted of a 60 W halogen bulb mounted in a 15 cm PVC tube, with a 0.6 s response time probe attached to its end, connected to a thermocouple. The probe measured the response temperature on the skin over the middle phalanges on the dorsum of the forefoot. The radiating heat stimulus from the bulb was instantaneously terminated with the foot-lift response of the tested animal. The nociceptive response to the 0.00 mg/kg dose was considered the baseline and subsequent measurements were expressed in difference from it. Data were evaluated in a regression analysis using the GLM procedure. A significant elevation (P < 0.0001) in the nociceptive threshold of the cows with cumulative dosing of morphine sulphate was noticed. A high variability (P < 0.0001) in the response among animals was also detected, suggesting that a 2-step dose of morphine sulphate is necessary to achieve a certain degree of induced analgesia in all cows. The nociceptive assay described, using the TTM device, was able to detect an elevation of the thermal threshold of cows due to morphine sulphate induced analgesia. An increase in locomotory behaviour or other side effects due to morphine sulphate were not noticed. 相似文献
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The relationship between liver steatosis, evaluated by ultrasonography, and various plasma haemostatic factors was examined in 64 apparently healthy males, aged 38 years. Plasma levels of factor VII clotting activity (F-VIIc), plasminogen activator inhibitor-1 (PAI-1) activity and antigen, tissue-type plasminogen activator (t-PA) activity significantly differed in men with liver steatosis (n = 31) as compared with those without steatosis (n = 33). No significant differences were found in t-PA antigen and F-VII antigen. The men with liver steatosis also had significantly higher body mass index (BMI), plasma triglyceride and 2 h post-load insulin concentrations. While the differences in plasma haemostatic factors were substantially unchanged after adjustment for BMI, they totally disappeared when further allowance was made for plasma triglyceride and 2 h insulin concentrations. In conclusion, these results indicate that liver steatosis correlates specifically with increased PAI-1, F-VIIc and decreased t-PA levels, and suggest that such a relation is largely mediated by concomitant alterations in plasma triglyceride and insulin concentrations. 相似文献