High prevalence of HIV infection among homeless and street-involved Aboriginal youth in a Canadian setting

Aboriginal people experience a disproportionate burden of HIV infection among the adult population in Canada; however, less is known regarding the prevalence and characteristics of HIV positivity among drug-using and street-involved Aboriginal youth. We examined HIV seroprevalence and risk factors among a cohort of 529 street-involved youth in Vancouver, Canada. At baseline, 15 (2.8%) were HIV positive, of whom 7 (46.7%) were Aboriginal. Aboriginal ethnicity was a significant correlate of HIV infection (odds ratio = 2.87, 95%CI: 1.02 – 8.09). Of the HIV positive participants, 2 (28.6%) Aboriginals and 6 (75.0%) non-Aboriginals reported injection drug use; furthermore, hepatitis C co-infection was significantly less common among Aboriginal participants (p = 0.041). These findings suggest that factors other than injection drug use may promote HIV transmission among street-involved Aboriginal youth, and provide further evidence that culturally appropriate and evidence-based interventions for HIV prevention among Aboriginal young people are urgently required.     

Factor V Leiden and other hypercoagulable state mutations are not associated with osteonecrosis during or after treatment for pediatric malignancy

OBJECTIVE: Osteonecrosis (ON) is a debilitating complication of cancer treatment in children and is usually associated with systemic steroid therapy. Defects of coagulation may be important in the pathogenesis of ON. This study evaluated the prevalence of factor V Leiden (FVL, 1691G-->A), the most common inherited thrombophilic state, the prothrombin 20210G-->A polymorphism, and the thermolabile methylene tetrahydrofolate reductase (MTHFR, 677C-->T) variant in a group of children in whom ON developed during or after treatment for cancer. STUDY DESIGN: Children in whom ON developed during cancer treatment at St Jude Children's Research Hospital were studied (n = 24). Genomic DNA was isolated, and polymerase chain reaction was performed to identify the FVL, prothrombin 20210, and thermolabile MTHFR mutations. RESULTS: Sixteen of 24 patients had acute lymphoblastic leukemia. The mean age at ON diagnosis was 14.4 +/- 3. 7 years. The mean interval between cancer diagnosis and ON diagnosis was 27 +/- 21 months. Twenty-two patients had received steroids for a mean duration of 24 +/- 15 weeks before having development of ON. No patient had a history of thrombosis. Five (21%) patients had a family history of thrombosis. Genetic analysis revealed 0 (0%) of 24 FVL, 1 (4.5%) of 22 prothrombin 20210, and 3 (13.6%) of 22 thermolabile MTHFR. None of these mutation frequencies was significantly different from our control frequencies or published values. CONCLUSIONS: Although procoagulant abnormalities in general and FVL in particular have been detected in a significant number of patients with ON of the jaw and Legg-Perthes disease, we did not identify an increased prevalence of FVL or other hypercoagulable state mutations in a cohort of children with ON that developed during or after treatment for a variety of cancers.     

Accuracy of passive ankle joint positioning during quiet stance in young and elderly subjects

Age-related postural deficits elicit compensatory mechanisms such as ankle dorsiflexion in the elderly. To gain further insight into this problem, the ability to match an ankle angle during quiet stance was studied in 12 elderly and 12 young subjects. Following an initial single limb angular perturbation presented in the ±4° range, a subject had to return a tilt platform to level, as determined by the nonperturbed limb. Elderly subjects exhibited significant positive (0.9°) over-shoot of the level position, in contrast to young subjects who matched ankle angle with a mean error of −0.1°. The elderly group also exhibited an increase in positioning error for angular displacements in the range between −1 and +1°. The results document age-related postural changes in ankle positioning which might affect postural stability in older adults.     

Recombinant urokinase for restoration of patency in occluded central venous access devices. A double-blind, placebo-controlled trial

The interval occlusion of central venous access devices (CVADs) remains a significant clinical problem, often requiring re-intervention for catheter exchange or replacement. The purpose of this Phase 3, multi-center, double-blinded study was to test the hypothesis that instillation of recombinant urokinase (r-UK) 5000 IU/ml is superior to placebo in restoring total catheter patency to an unselected cohort of occluded CVADs. After obtaining informed consent, adult and pediatric patients with occluded, non-hemodialysis CVADs of any duration or type were randomized (2 : 1) to receive either r-UK 5000 IU/ml or placebo instilled into all occluded lumens of their catheter. Catheter function was assessed at 5, 15 and 30 min after the first instillation. If the catheter remained occluded after 30 min, a second dose was instilled with repeat assessments at 5, 15 and 30 min. The primary efficacy variable was the restoration of catheter function to all treated lumens (i.e., total catheter patency) after one or two instillations. Catheters that were not successfully recanalized after two instillations were allowed to receive up to two instillations of open-label r-UK administered in the same manner. The primary safety variable was the occurrence of hemorrhagic and non-hemorrhagic events within 72 hr after instillation. A total of 180 patients were enrolled at 43 sites in the United States and Canada. Most patients were adults, although 20% were 相似文献   

Prevention of thromboembolism after neurosurgery for brain and spinal tumors

OBJECTIVE: Deep venous thrombosis (DVT) is a major cause of morbidity and mortality after surgery for primary and metastatic brain tumors. METHODS: We conducted a confidential survey of American neurosurgeons interested in tumor surgery to assess DVT risk awareness and thromboprophylaxis patterns. RESULTS: Of the 172 respondents, 108 (63%) underestimated the DVT risk after brain tumor surgery. After operating on patients who had brain or spinal tumors, 81.4 and 78.5% of respondents, respectively, reported using DVT prophylaxis. After performing brain tumor surgery, 76.2% of respondents reported using solely mechanical methods of prophylaxis "always" or "most of the time." CONCLUSION: American neurosurgeons tend to underestimate the risk of DVT associated with brain tumor surgery and to use mechanical thromboprophylaxis despite the availability of effective pharmacologic antithrombotics. A better appreciation of the risk of thrombosis, combined with clinical studies to address safety, may enhance the use of prophylaxis and the perceived safety of antithrombotics in this setting.     

Exogenous lung surfactant: effect on radiographic appearance in premature infants

At birth, premature infants of 25-29 weeks gestation, at high risk for development of neonatal respiratory distress syndrome (RDS), were given a single dose (90 mg) of calf lung surfactant extract (CLSE) by intratracheal instillation. The frequency and severity of RDS were assessed with use of a simple radiographic scoring system in which pulmonary parenchymal densities and the prominence of the air-bronchogram effect were used as indicators of widespread atelectasis. Radiographs were obtained in surfactant-treated and control infants within the first 90 minutes of life as part of an initial evaluation of their pulmonary status. Subsequent examinations were performed at less than 24 hours and less than 48 hours of age. Radiographic assessment of lung disease compared consistently with coordinated data on oxygen and mean airway pressure requirements of the infants. Both indicated a significantly decreased frequency and severity of RDS in the infants treated with surfactant. The results provide supporting evidence of the effectiveness of exogenous lung surfactant replacement in mitigating RDS in very premature infants.     

Thrombosis at venous insertion sites after inferior vena caval filter placement

Color Doppler flow imaging or compression ultrasound (US) was used to prospectively determine frequency of thrombosis at 54 venous insertion sites (47 in common femoral veins, seven in right internal jugular veins) after percutaneous placement of Greenfield filters for interruption of the inferior vena cava. Fifty-one filters were successfully placed in 51 patients with a dilator set or a balloon angioplasty catheter. Nine focal thrombi were detected in the common femoral vein (19%) and one in the right internal jugular vein (14%). Use of dilators induced eight thrombi (24%), compared with two (10%) from balloon catheters. The left common femoral vein had a high frequency of thrombosis, regardless of dilation technique (five of nine). Of nine patients with acute common femoral vein thrombosis, four became symptomatic within 10 days after the procedure. Patients may remain asymptomatic or have delayed symptoms; thus, US is valuable for determining patients at risk of thrombosis of the common femoral vein.