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991.
The purpose of this study was to review venous collateralization resulting from inferior vena cava obstruction. The elements responsible for the extent and distribution of venous collaterals in inferior vena cava obstruction and whether or not the obstructive lesion involves tributaries of the inferior vena cava. Common etiologies of inferior vena cava obstruction include extensions of iliofemoral vein thrombi, thrombosis from intraluminal tumors or following trauma, and external compression. The anatomy of the venous collateral systems may be divided into deep and superficial networks, each of which is composed of systems of primary or secondary clinical significance, as defined by the degree of restoration of adequate venous return and the extent of visceral venous decompression. The most common obstructions of the inferior vena cava involve the lower third of the vessel. The azygos-hemiazygos and vertebral venous plexus systems play the most significant roles, while the superficial systems are less prominently involved. In upper level inferior vena cava obstruction, reestablishment of venous circulation is less developed, which usually leads to a poorer clinical outcome. © 1992 Wiley-Liss, Inc.  相似文献   
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Semiempirical model for generating tungsten target x-ray spectra   总被引:7,自引:0,他引:7  
A semiempirical model for generating tungsten target x-ray spectra is presented. This model extends earlier work in two significant areas. First, both bremsstrahlung and characteristic x-ray production are assumed to occur at varying depths within the target. Second, optimal parameters for the model were determined from experimental spectra utilizing nonlinear least-squares techniques. As a result, good agreement is obtained between calculated and measured x-ray tube spectra and output for different target angles and a wide range of x-ray tube potentials. Such is not the case with previously published models.  相似文献   
994.
Relapses, exacerbations or attacks of multiple sclerosis are the dominating feature of relapsing-remitting multiple sclerosis (MS), but are also observed in patients with secondary progressive MS. High-dose methylprednisolone is the routine therapy for relapses at present, but other treatments are also in current use. The objective of the task force was to review the literature on treatment of MS relapses to provide evidence-based treatment recommendations. Review was carried out on the literature with classification of evidence according to the EFNS guidelines for scientific task forces. Short-term, high-dose methylprednisolone treatment should be considered for the treatment of relapses of MS (level A recommendation). The optimal glucocorticoid treatment regimen, in terms of clinical efficacy and adverse events, remains to be established. A more intense, interdisciplinary rehabilitation programme should be considered as this probably further improves recovery after treatment with methylprednisolone (level B recommendation). Plasma exchange is probably efficacious in a subgroup of patients with severe relapses not responding to methylprednisolone therapy, and should be considered in this patient subgroup (level B recommendation). There is a need for further randomized, controlled trials in order to establish the optimal treatment regimen for relapses of MS.  相似文献   
995.
Although a restricted hip range of motion has been previously associated with chronic groin injury the temporal course of this association remains unclear. Accordingly the purpose of this prospective cohort study was to report preliminary findings examining whether hip joint range of motion restriction is associated with subsequent onset of athletic chronic groin injury. End-range internal and external hip joint range of motion was determined in 29 elite Australian football players, without previous history of groin injury. The players were followed for two subsequent playing seasons for the development of chronic groin injury. Four athletes developed chronic groin injury defined as at least 6 weeks of groin pain and missing match playing time. In athletes that developed chronic groin injury a lower body weight (p = 0.02) and reduced total hip joint range of motion (p = 0.03) were found to be associated. This study suggests that hip stiffness is associated with later development of chronic groin injury and as such may be a risk factor for this condition. This work should be viewed as preliminary and caution is advised in applying the conclusion to clinical practice as the numbers in this study were small.  相似文献   
996.
This study examines the effect of a training program on long-term-care (LTC) surveyors' knowledge of factors affecting oral health and their behavior in citing oral health deficiencies of LTC residents. Twenty surveyors were recruited for the experimental group, along with a non-equivalent comparison group of 31 surveyors. The experimental group participated in a three-hour interactive, case-based training program. The experimental group had a significant increase in total knowledge (p < 0.002) post-test scores with a moderate effect size, η2= 0.115. The training program resulted in a statistically significant increase (p < 0.0001) In oral health citation behavior for the experimental group for six months following training. This study provides evidence that an interactive case-based training program can affect participants' knowledge regarding oral health of LTC residents and participants' oral health citation behavior. As the elderly popution experiences an Increased life expectancy with Increased need for assistance with Activities of Dally Living (ADL), similar training programs will become an important factor In assessing the quality of care provided to LTC residents.  相似文献   
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As little is known about how support assists individuals during a normative life transition, this qualitative, prospective study explored how women chose sources of informal support Women having their first child, returning to work after an extended absence or recently retired from full-time employment were interviewed Support during a life transition was described as having someone who would listen while the woman problem-solved Women preferred to get their support from close family members or others experiencing a similar life transition A number of barriers to the use of support were identified perception that the use of support would be a burden on others, lack of reciprocity, reluctance to ask for support, and nonsupportive messages included within supportive actions The transition often took more than 2 years to complete and, for a subgroup of women, involved major changes in their self-expectations and ability to access support The findings identify areas that nurses should consider in health promotion activities with women who are experiencing these life transitions  相似文献   
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