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951.
OV Krasilnikov CM Carneiro LN Yuldasheva AC Campos-de-Carvalho RA Nogueira 《Canadian Metallurgical Quarterly》1996,29(12):1691-1697
Porin isolated from bovine skeletal muscle was reconstitute in planar lipid bilayers under voltage clamp conditions. A set of non-electrolytes were used as molecular probes for determining the pore diameter. The maximal diameter of the open channel was estimated to be 3.02 +/- 0.26 nm. As observed for other porin channels, a large transmembrane potential drove the channel into a "closed" state. The channel transition to the low conductance (closed) state was followed by a decrease in the maximal diameter of the channel to 2.4 +/- 0.08 nm. 相似文献
952.
E Chen WL Nyhan C Jakobs CM Greco AJ Barkovich VA Cox S Packman 《Canadian Metallurgical Quarterly》1996,19(3):335-343
Chromolaena odorata (formerly Eupatorium odoratum) is used as a traditional medicine in Vietnam (Nghiem, 1992), where its Vietnamese common name is "co hoi." While it has been widely considered a weed by agriculturalists (Holm et al., 1991), the aqueous extract and the decoction from the leaves of this plant have been used throughout Vietnam for the treatment of soft tissue wounds, burn wounds, and skin infections. A number of clinical studies done by Vietnamese as well as foreign medical workers has demonstrated the efficacy of this extract on the wound-healing process. In this article, the effect of the Eupolin extract on hydrated collagen lattice contraction by human dermal fibroblasts, an in vitro model of wound contraction, is described. The significant inhibition of collagen gel contraction by Eupolin extract at 50 to 200 micrograms/ml is demonstrated in various concentrations of collagen. When the extract at 50 to 150 micrograms/ml was washed out of the lattices and replaced by fresh medium without Eupolin, the contraction of collagen by cells was resumed. The visualization of cells in the lattices by incubation in a tetrazolium salt for 2 h showed live cells at 50 to 150 micrograms/ml of extract. In contrast, all cells were killed in the higher extract doses of 300 or 400 micrograms/ml. These preliminary results showing the inhibitory effect of Eupolin extract on collagen contraction suggest that a clinical evaluation of its effect on wound contraction and scar quality should be made. This work illustrates that traditional remedies that are used by folk practitioners to improve healing can be examined in a scientific manner using in vitro wound-healing models. It could be that the synergistic properties of components of the natural extract contribute to the positive effects demonstrated on various wound-healing mechanisms. 相似文献
953.
CM Mueller T Colaizzo-Anas EP Shronts JA Gaines 《Canadian Metallurgical Quarterly》1996,96(8):764-8; quiz 769-70
OBJECTIVES: The purpose of the study was to describe the involvement of registered dietitians in parenteral nutrition (PN) orders, to identify characteristics of those who write orders; and to rank education, training, and support elements that dietitians believe facilitate PN order-writing skills. DESIGN: Mail survey method. SUBJECTS: Usable returned questionnaires (n = 266) represented randomly sampled membership of the Dietitians in Nutrition Support (a dietetic practice group of The American Dietetic Association) and registered dietitian membership of the American Society of Parenteral and Enteral Nutrition. STATISTICAL ANALYSIS: Data were analyzed using basic frequency displays on all questionnaire items, Pearson correlations between the quantitative variables, and one-way analysis of variance with each of the categorical variables and the quantitative variables. Detail exploration among variables was done by chi(2) analyses and two-tailed t tests. RESULTS: "Recommend" was the most frequent response to a query about participation in PN orders. An average of 37% of respondents sometimes or always wrote orders for nutrients. Specialists were more likely to write orders than clinicians and managers. No relationship was found between those who wrote orders and educational level, and writers had been registered for a shorter length of time. Agreement on the training and support needed for order-writing skills was nearly unanimous. APPLICATIONS: The PN skills of respondents who were specialists distinguished them from managers and clinicians. Specialists did not fit criteria for advanced practice, and specialty practice in metabolic nutrition care may be too broad to define their practice. Educators must recognize the importance of including PN training in didactic and clinical training programs. Registered dietitians with PN skills will be well positioned to play an active role in the evolving health care system. 相似文献
954.
OBJECTIVE: To identify the origin of eosinophils in cases of eosinophil-associated preterm delivery. METHODS: From an established set of 465 consecutive non-anomalous singleton infants delivered at 22-32 weeks' gestation, we retrieved 161 cases of preterm delivery following spontaneous onset of preterm labor, 78 cases with maternal preeclampsia, 33 cases of abruption, and 193 cases of premature rupture of membranes (PROM). Charts were reviewed, and the placenta, umbilical cord, and membranes were examined histologically. In cases with extravascular eosinophils showing evident gradient toward the amniotic cavity, the origin of the eosinophils (fetal or maternal) was determined by the proximity to fetal or maternal vessels. RESULTS: Histologic evidence of an eosinophilic gradient toward the amniotic cavity was present only in the fetal (including umbilical cord and chorion) compartments. This eosinophilic gradient was present in 19% (90 of 465) of preterm delivery cases and was significantly more common in cases of PROM (54 of 193, 28%) and preterm labor (34 of 161, 21%) than abruption (two of 33, 6%) and preeclampsia (none of 78) (P < .001). In 84 of 90 cases (93%), the eosinophilic gradient was present along with multiple histologic indicators of acute intrauterine inflammation. CONCLUSION: An eosinophilic gradient toward the amniotic cavity, present in nearly a fifth of cases of preterm delivery, is probably of fetal origin, making it unlikely that a maternal "allergy-like" mechanism is a cause of preterm delivery. 相似文献
955.
BACKGROUND: One way of establishing a morphogen gradient in a developing embryo involves the localized synthesis of an inducing molecule followed by its diffusion into surrounding tissues. The morphogen-like effects of the mesoderm-inducing factor activin provide support for this idea in amphibian development. The questions remain, however, of how activin exerts its long-range effects, and whether long-range signalling is a property of all transforming growth factor beta (TGF-beta) family members. RESULTS: We compare the signalling ranges of activin and two other TGF-beta family members, Xnr-2 and BMP-4. Unlike activin, Xnr-2 and BMP-4 act over short distances. Furthermore, the effects of constitutively active activin receptors are strictly cell-autonomous. These observations suggest that the long-range effects of activin occur through protein diffusion and that "relay' mechanisms are not initiated by any of these TGF-beta family members. Mechanisms limiting the signalling range of Xnr-2 were addressed by studying Xnr-2 processing and secretion. An activin-Xnr-2 fusion protein signals over many cell diameters, suggesting that regulated processing or secretion is one limiting factor. Disaggregation and reaggregation of Xnr-2-producing tissues also extends the range of Xnr-2, suggesting that components of intact tissue restrict spread of the protein. CONCLUSIONS: The long-range effects of activin are likely to occur through the diffusion of activin protein. The short-range effects of Xnr-2 and BMP-4 emphasize that long-range diffusion is not a general property of TGF-beta-related molecules. Finally, signalling ranges may be regulated by constraints on processing or secretion and by interactions with extracellular components of embryonic tissues. 相似文献
956.
BF Waller CM Orr J VanTassel T Peters E Fry J Hermiller LD Grider 《Canadian Metallurgical Quarterly》1996,19(12):960-966
Catheter balloon angioplasty is a well accepted form of nonsurgical treatment of acutely and chronically obstructed coronary artery vessels. It is also the centerpiece for various new intervention techniques. Their morphologic effects on the site of obstruction has been termed "remodeling." Part IV of this six-part series focuses on morphologic correlates of coronary angiographic patterns of remodeling after balloon angioplasty and discusses effects of angioplasty on adjacent, nondilated vessels. 相似文献
957.
A Kawashima CM Sandler IC Boridy N Takahashi GS Benson SM Goldman 《Canadian Metallurgical Quarterly》1997,168(4):997-1000
OBJECTIVE: The tissue rim sign-a rim or halo of soft-tissue attenuation seen around the circumference of an intraureteral calculus on unenhanced axial CT-has been described as useful in differentiating ureteral calculi from extraurinary abdominal or pelvic calcifications. The purpose of this study was to determine the prevalence of the tissue rim sign in patients with ureterolithiasis and extraurinary calcifications and to determine the relationship between the tissue rim sign, the size of a calculus, and the degree of urinary obstruction. MATERIALS AND METHODS: Unenhanced helical CT studies followed by excretory urography were obtained in 59 patients with suspected acute ureterolithiasis. Each calcification along the expected course of the ureter seen on axial CT scans was categorized as a ureteral calculus or as an extraurinary calcification. Each categorization was based on CT, urographic, and clinical findings and the presence or absence of a tissue rim sign. When the outer wall of the ureter could not be seen because there was no clear fat plane at the level of the calcification on CT, the sign was categorized as "indeterminate." The size of the calculus was measured on CT, and the degree of urinary obstruction was estimated on the basis of the urograms. RESULTS: Thirty-two patients each had a single ureteral calculus. Of these patients, CT revealed a positive tissue rim sign in 16 patients (50%), was negative in five patients (16%), and was indeterminate in 11 patients (34%). In addition, we saw 57 extraurinary calcifications in 18 patients (11 patients with ureteral calculi and seven patients without ureteral calculi). None of the 57 extraurinary calcifications was associated with a positive tissue rim sign. The tissue rim sign was negative in 39 (68%) of the 57 extraurinary calcifications and indeterminate in the remaining 18 (32%). Ureteral calculi with a negative tissue rim sign were larger than ureteral calculi with a positive tissue rim sign (p < .01). A high degree of obstruction was present in four of five patients with ureteral calculi for which CT showed a negative tissue rim sign. Conversely, six of 16 patients in whom CT revealed a positive tissue rim sign also had a high degree of obstruction. Therefore, no clear relationship was found between the degree of obstruction and the presence of a positive tissue rim sign. CONCLUSION: A positive tissue rim sign is specific for the diagnosis of ureterolithiasis. However, a negative tissue rim sign does not preclude such a diagnosis. The presence or absence of this tissue rim sign correlates with the size of a calculus but not with the degree of urinary obstruction. When CT reveals an indeterminate tissue rim sign, careful inspection for other CT findings, such as ipsilateral ureteral dilatation, perinephric edema, dilatation of the intrarenal collecting system, and renal swelling, is necessary. 相似文献
958.
JH Toney JK Wu KM Overbye CM Thompson DL Pompliano 《Canadian Metallurgical Quarterly》1997,9(3):355-362
Two new areas of anchor development are biodegradable anchors and "mini" anchors. The group of biodegradable anchors tested include the Bio-Anchor, LactoSorb, Biofix, Bio-Statak, Mini Screw suture anchor, DePuy 4.5 molded, DePuy 4.5 machined, DePuy 3.5 machined, TAG Wedge 4, TAG Rod 2, TAG Wedge 3, TAG Wedge 2, and Stealth. "Mini anchors" have drill holes or minor diameters of < 2.2 mm. Those tested include the Mini Revo and Bio-Anchor, miniHarpoon, mini Mitek and Fast in 3, Statak 1.5 and 2.5, SB 2 and PeBA 3, Corkscrew 5, Corkscrew 3.5, and Fastak A2, Ogden 2.5, TAG Wedge 2, ROC 1.9, and Questus 2.5. Additional anchors tested that fit neither category include the Anspach, Questus 3.5 and 5.0, SB 3 and PeBA-C, Ogden 3.5, Fast in 4, Ultrafix, and the ROC 3.5, ROC 2.8, ROC 2.3, and ROC XS. An anchor comparison, using an established protocol in fresh porcine femurs, recorded failure strength, failure mode, eyelet size, minor and major diameters, and drill hole sizes. Except for the Bio-Anchor and TAG Wedge 2, biodegradable anchors tend to be larger to compensate for their lower strength relative to metal. Biodegradable screw anchors' predominant failure mode was eyelet cutout, whereas biodegradable nonscrew anchors failed to predominantly by anchor pullout. From an initial mechanical perspective, these biodegradable anchors perform acceptably. Both biodegradable and "mini" anchors include screw and nonscrew designs. As expected, screw designs perform well and generally fail at higher loads than nonscrew anchors. Although biodegradable anchors, as a group, are not as strong as metal anchors, they are stronger than the sutures for which they are designed. The move to smaller ("mini") and biodegradable anchors is supported by these data. Whether an anchor fails at twice the suture breaking strength or 10 times the suture breaking strength should make no difference. 相似文献
959.
This study examines sources of motivation to seek treatment. Participants were 105 male alcoholics and their non-alcoholic female partners who participated in a study of three different approaches to the conjoint treatment of alcoholism. Participants' sources of motivation were coded from responses to questions at the initial clinical screening interview. Sources of motivation were classified as "internal" or "external." More participants had internal sources of motivation (74%) than external sources. Participants with internal sources of motivation scored higher on the Michigan Alcoholism Screening Test than participants with external sources of motivation, but did not differ on other measures of pretreatment severity of alcohol problems. About half of the participants (53%) cited their partner as a primary source of motivation to seek treatment. Other sources of motivation cited were: increasing problems with alcohol, mental health problems, and physical health problems. There was greater variability among internal sources of motivation than among external sources of motivation. Participants' partners but not the male participants themselves, experienced an increase in marital satisfaction from pre- to within-treatment when the participant was motivated to come to treatment by his partner. 相似文献
960.
DS Sharp CM Burchfiel JD Curb BL Rodriguez PL Enright 《Canadian Metallurgical Quarterly》1997,45(12):1464-1471
OBJECTIVE: To assess the joint characteristics of low standardized weight and compromised pulmonary function in predicting all-cause mortality. DESIGN: A population-based, prospective cohort study. SETTING: Oahu Island, Hawaii. PARTICIPANTS: Surviving Japanese-American men of the Honolulu Heart Program cohort, 71 to 93 years of age (N = 3059). MEASUREMENTS: Body mass index (BMI-weight in kilograms/square of height in meters) and 1-second forced expiratory volume (FEV1) as a percentage of age- and height-predicted FEV1 from the 1991 to 1993 examination of the cohort. Mortality data derived from the ongoing tracking of deaths of the cohort. Relations of selected risk factors among joint levels of BMI (< or = 21, > 21 to < 25, > or = 25 kg/m2) and percent predicted FEV1 (< or = 70%, > 70%) were determined. The impact of these covariates on relations between joint BMI/percent predicted FEV1 levels and subsequent all-cause mortality was assessed. RESULTS: The highest age-adjusted mortality rate (91.9 deaths per 1000 person-years) was noted among men characterized by the joint conditions of percent predicted FEV1 < or = 70% and BMI < or = 21 kg/m2. This rate was 4.0 times the mortality rate of a "healthy" reference group characterized by percent predicted FEV1 > 70% and 21 < BMI < 25 kg/m2. This rate ratio is attenuated to 3.2 upon statistical control for measures of current and past smoking behavior. Among the three strata of BMI, statistical interaction is reflected in a heterogeneity of mortality rate differences (49.7, 21.8, -9.6 deaths/person-year, respectively) and rate ratios (2.18, 1.98, .66, respectively) comparing men with percent predicted FEV1 < or = 70% to > 70%. CONCLUSION: Joint loss of pulmonary function and relative weight is predictive of subsequent all-cause mortality in excess of additive or multiplicative effects of each condition separately. Smoking behavior may contribute to this observation. 相似文献