Accumulation of methotrexate and methotrexate polyglutamates in lymphoblasts at diagnosis of childhood acute lymphoblastic leukemia: a pilot prognostic factor analysis

Lymphoblasts in bone marrow samples, obtained from 43 children with acute lymphoblastic leukemia at diagnosis, were incubated with 1.0 mumols/L [3H] methotrexate for 24 hours in vitro. Nonexchangeable methotrexate and methotrexate polyglutamates were separated and quantitated. Event-free survival at 5 years was 38% +/- 9% for all 43 patients (27 failures), and 44% +/- 10% for the 35 with non-T, non-B- cell acute lymphoblastic leukemia (20 failures). Of these 35 children, those whose lymphoblasts accumulated more than 100 pmol methotrexate and 500 pmol methotrexate polyglutamates per billion cells experienced better 5-year event-free survival than those whose lymphoblasts did not (65% +/- 12% v 22% +/- 9%, P = .010). This difference characterized "good-risk" patients who were female (P = .014), less than age 7 at diagnosis (P = .005), or had low initial white blood cell counts (less than 20 X 10(9)/L, P = .018). Findings were similar for the 43 children with acute lymphoblastic leukemia and for the "good-risk" children in this total group. Thus, the ability of lymphoblasts to accumulate methotrexate and form methotrexate polyglutamates may be important to the curative properties of current therapy of acute lymphoblastic leukemia in children, particularly for "good-risk" patients. In such patients, inherent rather than acquired drug resistance may be the initial event leading to treatment failure.     

Infarction of the choroid plexus

Infarction of the choroid plexus may result from ischemia in the distribution of the medial posterior choroidal artery. Diffusion-weighted imaging may depict this unusual stroke syndrome. The clinical and radiologic aspects of this rare condition are discussed taking into consideration the anatomy and pathophysiology of the choroid plexus.     

Incidence of injury in elite junior Rugby Union: a prospective descriptive study

The high incidence of injury in Rugby Union is well documented, particularly at elite levels of competition. This article describes the incidence and nature of all injuries sustained by elite Western Australian junior Rugby Union players during the 26 weeks up to and including the 1997 National Championship campaign. Informed consent was gained for each participant (n = 44) prior to completion of an extensive baseline questionnaire. Exposure and injury data were collected at each training session and game. The injury incidence rate over the 26 week period was 13.26/1000 player hours. Injury data were analysed by phase of play, position, severity and if occurred at games or training. The incidence of injury was significantly associated with the position played (chi2 = 67.49, p value = 0.008) and the phase of play in which the injury occurred (chi2 = 8.07, p value = 0.042). Tackling was the most dangerous phase of play (52% of injuries) and the most common site of injury was the lower limb (37%). Most injuries occurred during games (56%) and the flanker was the position most at risk of injury (12%). Further research is needed to identify the aetiology of injury at all levels of competition and to use these findings to develop effective injury prevention strategies in this sport. Position-specific risk factors should also be investigated, as should the mechanism of injury associated with tackling which is the phase of play in which significantly more injuries occur in rugby.     

普鲁卡因选择性涂丝电极稳定性的研究

涂丝电极的应用已很广泛,但其稳定性差限制了它的进一步推广应用。本文找出普鲁卡因涂丝电极稳定性差的原因,制备了以聚乙烯醇(含盐酸普鲁卡因)为内参的Ag-Agcl丝涂(PVC)膜电极,其稳定性大为提高,并有良好的响应性能。     

Lipomatous tumors of the liver: evaluation with CT and US

Seven cases of lipomatous masses within the liver parenchyma were demonstrated with computed tomography (CT). Five of these cases were obtained from a retrospective review of 50 cases of renal angiomyolipoma in which the liver was adequately demonstrated. The other two cases were from the files of the Armed Forces Institute of Pathology and had no associated renal lesions. Three of the five cases were associated with tuberous sclerosis. In all seven cases, the fatty tumors appeared on CT scans as a well-defined, 0.8-13-cm mass, with attenuation coefficients of less than -30 HU. On ultrasound studies, the lesions were well circumscribed, highly echogenic, and similar to hemangiomas. While distinctly rare lesions, these lipomatous masses are not as unusual as the literature would indicate. One may anticipate such masses in patients with renal angiomyolipomas and in a relatively high percentage of those with tuberous sclerosis.     

Prior antiplatelet use and infarct volume in ischemic stroke

BACKGROUND: Conflicting data exist on the role of antiplatelet agents in reducing incident ischemic stroke magnitude, but most prior studies used clinically-assessed neurologic deficit as the index of stroke extent rather than more precise volumetric measurements of infarct size. We assessed the relation of premorbid antiplatelet use to initial diffusion-weighted MRI (DWI) lesion volumes among acute ischemic stroke patients. METHODS: Consecutive patients presenting within 24 h of ischemic stroke over an 18-month period were studied. DWI lesions were outlined using a semi-automated threshold technique. Subjects were categorized into two groups: antiplatelet (AP) or no antithrombotic (NA). The relationship between prestroke antithrombotic status and DWI infarct volumes was examined using multivariate quantile regression. RESULTS: One hundred sixty-six individuals met study criteria: 75 AP and 91 NA patients. Median DWI volume was lower in the AP group than in the NA group (1.5 cc vs. 5.4 cc, p=0.031). A multivariable model (adjusting for age, history of transient ischemic attack, admission temperature, admission blood pressure, admission serum glucose, stroke onset to imaging interval, stroke mechanism, premorbid statin and antihypertensive use) demonstrated smaller infarcts in the AP vs. NA group (adjusted volume difference: -1.3 cc, 95% CI=-0.09, -2.5, p=0.037). Prior statin use, no history of TIA, large vessel atherosclerosis and microvascular ischemic disease stroke mechanism were also independently associated with reduced infarct volume. CONCLUSIONS: Prior antiplatelet treatment is independently associated with reduced cerebral infarct volume among acute ischemic stroke patients. Premorbid statin use, TIA history and stroke mechanism also predict infarct volume in ischemic stroke.     

Pachygyriclike changes: topographic appearance at MR imaging and CT and correlation with neurologic status

Studies of 23 pediatric patients with pachygyriclike changes (PLCs) examined with computed tomography (CT) and magnetic resonance (MR) imaging were reviewed to determine topographic patterns and correlate them with various clinical syndromes and degrees of neurologic impairment. Three types of topographic distributions were identified: unilateral, diffuse, and bilateral nondiffuse (of which eight of 10 showed frontotemporal predominance). PLCs were an isolated finding in seven patients, were associated with various congenital syndromes in nine patients, and were associated with congenital infection in seven patients, six of whom showed marked white matter abnormalities. Although most patients had severe developmental delay, three with nondiffuse PLCs had less severe impairment, permitting less required care.