Acute neurologic dysfunction associated with high-dose chemotherapy and autologous bone marrow rescue for primary malignant brain tumors

Acute neurologic complications occurred 103 times in 50 (54%) of 92 patients (primarily children) treated with high-dose chemotherapy and autologous bone marrow rescue for primary central nervous tumors. Different types of neurologic compromise occurred during the chemotherapy infusion as compared to the first 100 days after the chemotherapy and the greater-than-100-day time period. The causes of the neurologic compromise were also time sensitive. BACKGROUND: Results of treatment for children with primary brain tumors using high-dose chemotherapy with autologous marrow rescue (ABMR) have been encouraging. However, the neurotoxicity associated with this technique remains a major concern. We reviewed the records of 92 patients who underwent ABMR for malignant brain tumors between 1986 and 1992 for the occurrence and timing of acute neurologic dysfunction (AND). METHODS: Individual investigators at the participating institutions retrospectively completed standardized forms on each patient. The manner in which the distribution of AND versus time of treatment emerged led to the establishment of distinct time periods for data analysis and discussion. The pre-ABMR period included those events that occurred during the chemotherapy infusion, the early posttreatment period included the first 100 days following bone marrow rescue, and the late posttreatment period was greater than 100 days following bone marrow rescue. RESULTS: Fifty patients (54%) had 103 episodes of AND. AND included encephalopathies with or without hallucinations or coma (32), seizures (23), headaches (9), ataxia-tremor-dysarthria syndrome (7), anorexia and nausea syndrome (7) and others (25). During the chemotherapy infusion, encephalopathies and seizures were most common. Hallucinations occurred primarily related to drug infusion, while encephalopathies without hallucinations were usually due to demonstrable dysmetabolic states. In the 100 days following ABMR, dysmetabolic states and iatrogenic factors caused 45% and progressive disease caused 33% of AND. Greater than 100 days from ABMR, progressive disease caused 55% of AND; 7 patients were noted to develop chronic anorexia and nausea of unclear etiology. The occurrence of neurologic compromise was not related to the chemotherapy regimens, tumor histology, tumor location, patient age, prior treatment, or the amount of tumor at time of treatment. Dexamethasone use was the only clinical factor associated with AND (p < 0.004). CONCLUSIONS: The cause of AND was definable for 95% of instances that occurred within 100 days of ABMR. Early AND was often iatrogenic and reversible. The greater the time from ABMR the more likely AND was due to progressive disease. Clinical factors could not predict the occurrence of AND as only the concurrent use of dexamethasone at the time of treatment proved significant. Although frequent, AND should not be considered a limiting toxicity of this approach or preclude the use of this technique.     

Improved large-signal quasistatic MESFET model

Improvements to the quasistatic modelling procedure which has been established by Rauscher and Willing (1978, 1979) are discussed. Specifically, a more accurate method of modelling the channel conductance and a technique for establishing the correct DC bias conditions within the MESFET model are provided.<>     

Selective termination and elective reduction in twin pregnancies: 10 years experience at a single centre

Selective termination is employed in multifetal pregnancies, in the presence of an abnormal fetus, in order to improve the prognosis of the normal fetuses. The term elective reduction is used to describe reduction in twin pregnancies for maternal medical conditions, psychological, or socioeconomic reasons. The purpose of this study was to evaluate the factors that influence outcome in such pregnancies. Eighty-two twin pregnancies underwent selective termination (n = 59) or elective reduction (n = 23) over a 10-year period. Early procedures, performed < or = 14 weeks (n = 31), had a pregnancy loss of 9.7% and a mean procedure-to-loss interval of 4.1 +/- 2.8 weeks; mean birthweight was 3299 +/- 395 g in survivors, with a mean gestational age at delivery of 38.4 +/- 2.3 weeks. In comparison, procedures performed > 14 weeks (n = 51) had a pregnancy loss of 7.8%, with a procedure-to-loss interval of 1.2 +/- 0.6 weeks. Mean birthweight was 2577 +/- 999 g, with a mean gestational age at delivery of 35.7 +/- 5 weeks. In conclusion, outcomes were more favourable among patients who underwent a first trimester procedure. The slight increase in pregnancy loss may be attributed to a higher than expected rate of spontaneous abortions in the first trimester, as manifested by the higher procedure-to-loss interval after a first trimester procedure. These facts underscore the importance of early detection of fetal abnormalities in twin pregnancies by ultrasonography and chorionic villus sampling.     

Partial purification and characterisation of potato pectinesterase

Pectinesterase (EC 3.1.1.11) was extracted from potato (Solanum tuberosum var. Russet Burbank) tissue and purified 9.6-fold by ammonium sulphate precipitation and chromatography on Sephadex G-100. The enzyme preparation thus obtained has a molecular weight of 25,000, an apparent K_m of 0.09% for citrus pectin and a pH optimum of 7.5. NaCl is a positive modulator of the enzyme. The energy of activation of the enzyme is 6200 calories. A Q₁₀ of 1.33 is observed in the temperature range of 25 to 45°C, and the optimum temperature for the enzyme is 55°C.     

Experimental determination of the backscatter factor for soft X-rays in water and acrylic glass

Experimental results are presented for the backscatter factor of X-rays with tube voltages up to 60 kV. The investigation were carried out with a transmission extrapolation chamber. A detailed account is given of how the air kerma measurements were evaluated in order to yield the backscatter factor. The limitations of the technique are critically analyzed. The final results, which are estimated to have an uncertainty of less than ±0.01, appear to be more accurate than the data on backscatter factors available hitherto.     

Epilogue: Why no standards for computer-based testing and test interpretation?

This paper provides a brief overview of the topics discussed by the contributors to this special issue. The focus of the paper, however, is on a single issue, an examination of the need for standards for computer-based tests and test interpretation. Questions about the value of the standard setting process are examined.