Removal of volatile and semivolatile organic contamination from soil by air and steam flushing.

A soil core, obtained from a contaminated field site, contaminated with a mixture of volatile and semivolatile organic compounds (VOC and SVOC) was subjected to air and steam flushing. Removal rates of volatile and semivolatile organic compounds were monitored during flushing. Air flushing removed a significant portion of the VOC present in the soil, but a significant decline in removal rate occurred due to decreasing VOC concentrations in the soil gas phase. Application of steam flushing after air flushing produced a significant increase in contaminant removal rate for the first 4 to 5 pore volumes of steam condensate. Subsequently, contaminant concentrations decreased slowly with additional pore volumes of steam flushing. The passage of a steam volume corresponding to 11 pore volumes of steam condensate reduced the total VOC concentration in the soil gas (at 20 degrees C) by a factor of 20 to 0.07 mg/l. The corresponding total SVOC concentration in the condensate declined from 11 to 3 mg/l. Declines in contaminant removal rates during both air and steam flushing indicated rate-limited removal consistent with the persistence of a residual organic phase, rate-limited desorption, or channeling. Pressure gradients were much higher for steam flushing than for air flushing. The magnitude of the pressure gradients encountered during steam flushing for this soil indicates that, in addition to rate-limited contaminant removal, the soil permeability (2.1 x 10(-9) cm2) would be a limiting factor in the effectiveness of steam flushing.

Assessment of foot-to-foot bioelectrical impedance analysis for the prediction of total body water.

OBJECTIVE: To investigate the accuracy of foot-to-foot impedance methodology for the prediction of total body water and whether leg length rather than stature should be used in the prediction of total body water. DESIGN: Cross-sectional study using volunteers from the community. SETTING: University laboratory. SUBJECTS: 57 subjects (29 male; 28 female) aged 19-56 y. INTERVENTIONS: Total body water was measured using a deuterium oxide dilution technique. Total body water was also predicted using foot-to-foot impedance apparatus (Tanita Inc, Tokyo, Japan, Model TBF 305). RESULTS: Mean values for predicted and measured total body water differed by 0.71. However this bias was not constant across all individuals with a progressive underestimation of total body water by foot-to-foot impedance technology as the water content of the body increases. Also the use of leg length did not improve the accuracy of the prediction equation. CONCLUSIONS: At the population level predictions of total body water obtained from foot-to-foot impedance technology compare well with measured total body water. However the significant correlation between the difference between predicted and measured total body water and the absolute value for total body water is a concern especially if the technology is used for body composition assessment during a weight loss program.

Autoerythrocyte sensitization.

We have seen six examples of autoerythrocyte sensitization in children that allow a definition of the disorder in the pediatric age group. The typical skin lesion is a painful, erythematous bruise that starts after minor trauma or surgery and often involves an area away from the injury site. The skin manifestations can be debilitating, and reappear unpredictably for an indefinite period. Somatic symptoms can be associated with the bruising. Usually the children have a disturbed psychological background. Characteristically, multiple detailed investigations are performed before the diagnosis is made. An intradermal injection of autologous red cells may or may not give a "positive" ecchymotic reaction. Pediatric patients seem to respond well to psychotherapy, which is usually the only effective form of treatment.

Diagnostic value of the Hemalog D-90 in classifying acute childhood leukaemias.

Accurate classification of the acute leukaemias is dependent not only on morphological characteristics, but also on cytochemical staining properties of the blasts in peripheral blood and bone marrow. This study was undertaken to evaluate the Hemalog D-90, an automated cytochemistry system for white cell differential counts, as an adjunct to conventional microscopy in the classification of acute childhood leukaemias. Fifty-two patients were classified according to morphology and cytochemical reactions of the cells obtained from peripheral blood. In 29 with classical acute lymphoblastic leukaemia (ALL), the Hemalog D showed the lymphoblasts to be non-peroxidase staining and these were recorded mainly as lymphocytes. In contrast, the blasts of eight patients with acute myeloblastic leukaemia (AML) were peroxidase positive, being recorded as neutrophils. Of the remaining 15 patients, 10 were classified as "Probably ALL' because they lacked some of the morphological or cytochemical criteria for classical ALL, while five were unclassifiable. However, in all these 15 patients the Hemalog D results were similar to those obtained in patients with classical ALL. We concluded that the Hemalog D was a useful adjunct in distinguishing ALL from AML, including the morphologically indistinct types.

Studies of globin chain synthesis and globin mRNA content in a patient homozygous for hemoglobin Lepore.

Globin chain synthesis and globin mRNA content were studied in blood cells of a patient homozygous for Hb Lepore. Peripheral blood cells incubated with tritiated leucine synthesized approximately 1.5 to 3% as many Lepore globin chains as alpha chains. Globin mRNA in peripheral blood cell RNA was assayed by molecular hybridization assays using human alpha and beta cDNA, and the results indicated the presence of approximately 1% to 2% as much beta-like mRNA (presumably deltabeta Lepore mRNA) as alpha mRNA. The amount of Lepore deltabeta chain mRNA in peripheral blood cells is therefore proportional to the amount of Lepore globin chain synthesis in the same cells. An incidental observation was the finding that peripheral blood cell RNA of this patient, at a time when she was being heavily transfused, contained substantially higher levels of beta-like mRNA (relative to alpha mRNA) than in subsequent studies. Cell-free translation of this mRNA however revealed that it contained authentic beta chain mRNA which must have been derived in some way from the transfused blood cells.

Idiopathic thrombocytopenic purpura in children: should corticosteroids be given?

Life-threatening hemorrhages occur in about 2% of children with idiopathic thrombocytopenic purpura (ITP), the majority during the first month of illness. The administration of corticosteroids to patients with ITP has been shown to improve platelet economy mainly through reduction of phagocytosis in the spleen. Since the risk of a short course of steroids in low dosage is small, it seems reasonable to administer them to patients with ITP during the period of greatest risk.

Dermatophyphics in childhood leukemia.

The dermatoglyphics of 54 leukemic children do not differ significantly from those of 25 mothers and 592 unrelated controls with respect to frequency of digital pattern types, position of axial triradius, or type of palmar flexion creases. These findings do not support the hypothesis that children with leukemia have an increased frequency of unusual dermal patterns, but suggest that the dermatoglyphics of leukemic children are not distinctive and therefore have no practical value in the diagnosis of childhood leukemia. Whatever factors are responsible for the development of leukemia in children, these factors do not appear regularly to affect the differentiation of the dermal ridges.