Outcomes of a randomized trial of hyperfractionated cranial radiation therapy for treatment of high-risk acute lymphoblastic leukemia: therapeutic efficacy and neurotoxicity.

PURPOSE: We evaluated 8-year survival and late neuropsychologic toxicity in children with acute lymphoblastic leukemia treated in a randomized clinical trial to test whether hyperfractionated (twice daily) cranial radiation therapy (CRT) can reduce incidence and severity of late toxicities associated with 18 Gy of CRT. PATIENTS AND METHODS: Between 1987 and 1995, 369 children treated on two consecutive Dana-Farber Cancer Institute Consortium protocols for high-risk acute lymphoblastic leukemia were randomly assigned to conventionally fractionated CRT (CFX) or hyperfractionated CRT (HFX) to a total dose of 18 Gy. Neuropsychologic testing was completed for 125 of 287 children in continuous complete remission. Event-free and overall survival, as well as neuropsychologic function, were compared for the two arms of the protocol. RESULTS: Eight-year event-free survival (+/- SE) was 80% +/- 3% for children randomly assigned to CFX and 72% +/- 3% for HFX (P =.06). Overall survival was 85% +/- 3% for CFX and 78% +/- 3% for HFX (P =.06). CNS relapses occurred in 2.8% of patients receiving CFX and 2.7% receiving HFX (P =.99). Cognitive function for both groups was solidly in the average range, with no group differences in intelligence, academic achievement, visuospatial reasoning, or verbal learning. Children on the HFX arm exhibited a modest advantage for visual memory (P <.05). CONCLUSION: HFX provides no benefit in terms of cognitive late effects and may compromise antileukemic efficacy. HFX should not be substituted for conventionally dosed CRT in children who require radiation therapy for treatment of acute lymphoblastic leukemia.     

Multimodal therapy with intravenous biweekly leucovorin, 5-fluorouracil and irinotecan combined with hepatic arterial infusion pirarubicin in non-resectable hepatic metastases from colorectal cancer (a European Association for Research in Oncology trial).

BACKGROUND: The purpose of this study was to evaluate the tolerance and efficacy of combining i.v. irinotecan, 5-fluorouracil (5-FU) and leucovorin (LV) with hepatic arterial infusion (HAI) of pirarubicin in non-resectable liver metastases from colorectal cancer. PATIENTS AND METHODS: Thirty-one patients were included in a phase II trial with i.v. irinotecan/5-FU/LV administered every 2 weeks, combined with HAI pirarubicin 60 mg/m(2) on day 1 every 4 weeks. In most cases HAI was administered via a percutaneous catheter. RESULTS: The main grade 3/4 toxicity was neutropenia, encountered in 78% of the patients. When all patients were considered in the analysis, tumour response rate was 15 out of 31 [48%; 95% confidence interval (CI) 32% to 65%]. Liver resection was made possible in 11 patients (35%; 95% CI 21% to 53%). There were no toxic death. Median overall survival was 20.5 months, and median progression-free survival was 9.1 months. In patients with completely resected metastases, median overall survival was not reached and median progression-free survival was 20.2 months. CONCLUSION: The multimodality approach used in the present study was well-tolerated and yielded dramatic responses. An aggressive approach combining i.v. and HAI chemotherapy deserves further investigation.     

德国医疗卫生产业浅谈

德国人口不到9000万，政府对医疗卫生管理实行分层次操作(见表1)。德国的医生分为住院医疗医生和诊所医生。联邦医生联合会负责医生的管理工作，该机构主要负责医生的继续医学教育、职称晋升、医疗纠纷的调解等。保险医生联合会则负责支付医生的各种费用。     

新加坡医卫模式冲击波

“10年内，世界上最大的国际性医疗集团将产生在中国!”新加坡百汇康护集团私人有限公司副总裁佘伟彦如此预言。     

PBPK model for radioactive iodide and perchlorate kinetics and perchlorate-induced inhibition of iodide uptake in humans.

Detection of perchlorate (ClO4-) in several drinking water sources across the U.S. has lead to public concern over health effects from chronic low-level exposures. Perchlorate inhibits thyroid iodide (I-) uptake at the sodium (Na+)-iodide (I-) symporter (NIS), thereby disrupting the initial stage of thyroid hormone synthesis. A physiologically based pharmacokinetic (PBPK) model was developed to describe the kinetics and distribution of both radioactive I- and cold ClO4- in healthy adult humans and simulates the subsequent inhibition of thyroid uptake of radioactive I- by ClO4-. The model successfully predicts the measured levels of serum and urinary ClO4- from drinking water exposures, ranging from 0.007 to 12 mg ClO4-/kg/day, as well as the subsequent inhibition of thyroid 131I- uptake. Thyroid iodine, as well as total, free, and protein-bound radioactive I- in serum from various tracer studies, are also successfully simulated. This model's parameters, in conjunction with corresponding model parameters established for the male, gestational, and lactating rat, can be used to estimate parameters in a pregnant or lactating human, that have not been or cannot be easily measured to extrapolate dose metrics and correlate observed effects in perchlorate toxicity studies to other human life stages. For example, by applying the adult male rat:adult human ratios of model parameters to those parameters established for the gestational and lactating rat, we can derive a reasonable estimate of corresponding parameters for a gestating or lactating human female. Although thyroid hormones and their regulatory feedback are not incorporated in the model structure, the model's successful prediction of free and bound radioactive I- and perchlorate's interaction with free radioactive I- provide a basis for extending the structure to address the complex hypothalamic-pituitary-thyroid feedback system. In this paper, bound radioactive I- refers to I- incorporated into thyroid hormones or iodinated proteins, which may or may not be bound to plasma proteins.     

Cryopreservation of Mycobacterium tuberculosis Complex Cells

Successful long-term preservation of Mycobacterium tuberculosis cells is important for sample transport, research, biobanking, and the development of new drugs, vaccines, biomarkers, and diagnostics. In this report, Mycobacterium bovis bacillus Calmette-Guérin and M. tuberculosis H37Ra were used as models of M. tuberculosis complex strains to study cryopreservation of M. tuberculosis complex cells in diverse sample matrices at different cooling rates. Cells were cryopreserved in diverse sample matrices, namely, phosphate-buffered saline (PBS), Middlebrook 7H9 medium with or without added glycerol, and human sputum. The efficacy of cryopreservation was quantified by microbiological culture and microscopy with BacLight LIVE/DEAD staining. In all sample matrices examined, the microbiological culture results showed that the cooling rate was the most critical factor influencing cell viability. Slow cooling (a few degrees Celsius per minute) resulted in much higher M. tuberculosis complex recovery rates than rapid cooling (direct immersion in liquid nitrogen) (P < 0.05). Among the three defined cryopreservation media (PBS, 7H9, and 7H9 plus glycerol), there was no significant differential effect on viability (P = 0.06 to 0.87). Preincubation of thawed M. tuberculosis complex cells in 7H9 broth for 20 h before culture on solid Middlebrook 7H10 plates did not help the recovery of the cells from cryoinjury (P = 0.14 to 0.71). The BacLight LIVE/DEAD staining kit, based on Syto 9 and propidium iodide (PI), was also applied to assess cell envelope integrity after cryopreservation. Using the kit, similar percentages of “live” cells with intact envelopes were observed for samples cryopreserved under different conditions, which was inconsistent with the microbiological culture results. This implies that suboptimal cryopreservation might not cause severe damage to the cell wall and/or membrane but instead cause intracellular injury, which leads to the loss of cell viability.