The effect of antiserum fractions on Ehrlich ascites tumour cells

Hyperimmune heterologous serum produced in sheep against mouse Ehrlich ascites tumour cells was absorbed with normal mouse tissue and fractionated by DEAE column chromatography into IgG1 and IgG2 fractions. In vitro cytotoxicity test showed that sheep anti-Ehrlich ascites tumour IgGl fraction was cytotoxic to (51)Cr labelled tumour cells whereas IgG2 had no cytotoxic effect. Pretreatment of the tumour cells with the non-cytotoxic IgG2 fraction slightly inhibited the cytotoxic action of IgG1 in vitro.When EAT cells were coated with either IgG1 or IgG2 by preincubation in vitro before injecting intraperitoneally into mice, both fractions protected the animals against tumour growth. Injection of IgG2 and IgGl fractions separately, one before and the other after the injection of EAT cells, resulted in partial protection only. The difference encountered between the in vitro and in vivo findings could be attributed to the host defence mechanisms involved in the in vivo test system.

Infrared-to-Millimeter, Broadband, Solid State Bolometer Detectors

Two versions of a thermal detector have been developed combining broadband response over the entire near infrared-to-millimeter region, room temperature operation, solid state construction, and amenability to absolute calibration. The sensitive detector version has a noise equivalent power (NEP) near 7 x 10(-10) W/Hz((1/2)) with a time constant of 6 msec. The power measuring bolometer version has a sensitivity near 10(-8) W for a 3-sec time constant. The basic construction uses a flake thermistor as a temperature sensor in combination with an optimized radiation absorber.

Drug effects on dieldrin storage in rat tissue

Selected drugs were tested for effectiveness in reducing dieldrin retention by rats. Female rats were fed diets treated to contain 1 ppm dieldrin. The drugs were administered as feed additives or by i.p. injections. The rats were sacrificed after 10 days of treatment and abdominal adipose tissue was analyzed for dieldrin using electron capture gas chromatography.Heptabarbital (40 and 225 mg/kg rat/day), aminopyrine (75 and 350 mg/kg rat/day), tolbutamide (60 and 290 mg/kg rat/day), and phenylbutazone (90 mg/kg rat/day) were effective as feed additives in reducing tissue dieldrin. Heptabarbital was the most effective and reduced the concentration of tissue dieldrin by 80 per cent at the higher dose level. In comparison, DDT (4 mg/kg rat/day) effected a 72 per cent reduction. A contrast with DDT was also observed in trials with i.p. administration of drugs and DDT. In those trials, the duration of the DDT action was apparently greater than that of the drugs.We suggest that suitable drugs might be used to reduce insecticide accumulation in the tissues of animals and man, and for treatment of individuals after over exposure to insecticides.

Changes in mouse 7S gamma-globulin resulting from immunization with transplantable tumours

The antibody response of A strain mice to immunization with C57BL mouse leukaemia, EL4, is confined to the 7S γ-globulin.

A rapid chromatographic method has been developed for the isolation of mouse 7S γ-globulin in a high state of purity as judged by immunological and electrophoretic techniques.

The apparent molecular weight (M_SD) of the immune γ-globulin preparation did not differ significantly from that of the normal γ-globulin preparation.

However, weight average (M_W) and Z average (M_Z) molecular weights determined from sedimentation equilibrium experiments showed differences in the two preparations. The M_Z/M_W ratios showed that the molecular polydispersity in the immune sample was significantly greater than that in the normal sample.