Second central nervous system prophylaxis in children with acute lymphoblastic leukemia who relapse after elective cessation of therapy

A treatment plan to achieve better disease control in patients with acute lymphoblastic leukemia (ALL) who relapse after elective cessation of therapy was assessed. The principal modifications were (1) a second preventive treatment of the central nervous system (CNS) at relapse and every six weeks throughout therapy, using intrathecal methotrexate with cytosine arabinoside, and (2) a four-week course of systemic chemotherapy given immediately before therapy was stopped a second time. Twenty-four patients were studied. There have been no meningeal relapses, in contrast to seven among 16 similar patients who were retreated without CNS prophylaxis. Although the median length of second hematologic remission was not significantly different from the outcome in the comparison group, a much higher proportion of patients (eight of 24 versus zero of 17) remain in prolonged reinduced complete remission (48-79 months). Children whose first relapse occurred later than six months after cessation of therapy had significantly longer subsequent remissions. These end results establish the value of intrathecal CNS prophylaxis in relapsed ALL and suggest that a late intensive phase of therapy will extend remissions in a substantial proportion of patients.     

DIRECT ACTION OF 4-AMINOPYRIDINE ON THE CONTRACTILITY OF A FAST-CONTRACTING MUSCLE IN THE CAT

The effects of 4-aminopyridine on the contractility of the fast-contracting tibialis anterior and the slow-contracting soleus muscles of cats under chloralose anaesthesia have been studied. 2. 4-Aminopyridine, in doses of 0.5 mg/kg and above, produced a slowly developing increase in the twitch tension of directly stimulated chronically denervated and of indirectly stimulated innervated tibialis anterior muscles, but had little or no effect on twitches of soleus muscles. The effect on innervated tibialis anterior muscles was more pronounced than that on chronically denervated muscles, but it was nevertheless concluded that the whole effect on innervated muscles was the result of a direct action on the muscle fibres. The simultaneously occurring facilitatory action on neuromuscular transmission, which is manifested in the anti-curare action of 4-aminopyridine, had a faster time-course and occurred in both the tibialis anterior and the soleus muscles. 3. 4-Aminopyridine antagonized dantrolene sodium on the tibialis anterior muscle but not on the soleus muscle. The antagonism could be described as physiological antagonism since it simply reflected the opposing actions on contractility of the two drugs. 4. 4-Aminopyridine was without effect on maximal tetanic tension of either the tibialis anterior or the soleus muscle. 5. It seems clear from the literature that a species difference exists with regard to the ability of 4-aminopyridine to increase muscle contractility. The results described in this paper show that muscle differences within the same species also exist.     

Toxicity of metal ions to alveolar macrophages

Significant concentrations of metals are found in the respirable particulate effluents associated with metallurgical smelters. In this investigation the effects of the metallic ions lead, cadmium, iron, mercury, aluminum, chromium, and nickel on various aspects of alveolar macrophage function were studied. The production of antibacterial substances (ie, reactive forms of oxygen) by these cells and oxygen consumption are very sensitive to the metals. Particle uptake displays moderate sensitivity, while lysosomal enzyme activity and membrane integrity are fairly resistant to metals. In addition, the effects of the organic solvents carbon tetrachloride, toluene, and xylene on alveolar macrophage function were tested. These solvents were found to inhibit oxygen consumption and the release of antibacterial substances while not greatly affecting membrane integrity. The results of these experiments indicate that some metals and some organic substances are toxic to alveolar macrophage function.     

Elevation of blood lead concentration by confinement in the rhesus monkey

Summary Rhesus monkeys were exposed to lead (Pb) acetate under various regimens during the first 12 months of life. At 30 months of age, these animals and unexposed controls were confined to an unfamiliar experimental chamber for one week. Serum cortisol concentration and Pb concentration in whole blood (PbB) were measured prior to, during, and after this confinement. Cortisol concentrations rose 60–90% within 2 hours of confinement, and declined to baseline levels after 98 hours of confinement. Mean baseline PbB levels reflected the state of clearance of the previously-ingested lead, rose 25–35% within 2 hours of confinement, and reached mean maximum levels as much as 100% above baseline after 98 hours of confinement. The data are discussed in terms of hormonal mobilization of Pb stored in bone, and subgest (1) that this storage is multicompartmental, (2) that more than one process is probably involved in its mobilization, (3) that cortisol probably does not directly affect PbB levels, and (4) that stress should be considered a potential factor in determining the PbB in studies of Pb metabolism.     

Comparison of intraoperative nitroprusside unloading in mitral and aortic regurgitation.

To compare the hemodynamic effect of vasodilator therapy on different regurgitant lesions, we infused sodium nitroprusside intraooperatively in 12 patients with mitral regurgitation and 15 with aortic regurgitation. During the critical period preceding establishment of cardiopulmonary bypass, both groups had developed intense vasoconstriction and cardiac decompensation. All demonstrated improved cardiac function with vasodilator therapy; however, the degree of improvement with nitroprusside differed in the two groups. Stroke volume increased 10 ml. per beat per meter squared in those patients with aortic regurgitation and only 6 ml. per beat per meter squared in those with mitral regurgitation (p less than 0.05). The percent increase in stoke volume induced by nitroprusside was inversely correlated to the preoperative left ventricular ejection fraction (r = 0.44, p less than 0.02). Patients with aortic regurgitation had lower preoperative left ventricular ejection fractions than those with mitral regurgitation (0.53 versus 0.63, p less than 0.02). Therefore, we conclude that patients with aortic regurgitation derived greater intraoperative hemodynamic benefit from unloading with nitroprusside, because they came to surgery with greater impairment of left ventricular contractility. Although nitroprusside improved cardiac function in both groups, only the patients with aortic regurgitation achieved normal pulmonary artery pressure (17 torr) and pulmonary vascular resistance (2.1 units) as a result of unloading. Those with mitral regurgitation continued to have pulmonary hypertension (28 torr) and increased pulmonary vascular resistance (3.9 units) despite vasodilator therapy. Thus the data suggest that patients with mitral regurgitation derived less hemodynamic benefit from intraoperative nitroprusside therapy because they were also limited by right ventricular dysfunction and a less responsive pulmonary vasculature.     

Determination of sodium saccharin in animal feed,wastewater and human urine by high-pressure liquid chromatography

Analytical methods are described for sodium saccharin in animal feed, wastewater and human urine at levels as low as 10, 0.1 and 10 ppm, respectively. Samples of animal feed and wastewater are subjected to liquid-liquid partitioning then the feed is further cleaned up on a column of silica gel prior to analysis by high-pressure liquid chromatography (HPLC) using a paired-ion mobile phase and an ultraviolet detector set at 230 nm. Samples of human urine require a cleanup on a column of XAD-2 prior to the partitioning and silica gel steps as well as an adjustment in the composition of the mobile phase to quantify saccharin. Data concerning partition values and the stability of sodium saccharin in animal feed are also presented.     

NAD(P) Glycohydrolase Deficiency in Human Erythrocytes and Alteration of Cytosol NADH-Methemoglobin Diaphorase by Membrane NAD-Glycohydrolase Activity

Erythrocytic NADH methemoglobin diaphorase acquires NADH-dichlorophenolindophenol diaphorase activity when enzyme-associated NAD is removed. This transformation is reversible and can be mediated by membrane NAD glycohydrolase (EC 3.2.2.5) in hemolysates as well as in intact cells exposed to hydrogen peroxide. It is abolished either in NADH methemoglobin diaphorase deficiency or in NAD(P) glycohydrolase (EC 3.2.2.6) deficiency which is common in Afro-American but not in European-American adults. Activities of erythrocytic NADP glycohydrolase and NAD glycohydrolase appear to depend on a single membrane enzyme.