Mental capability of children exposed to lead pollution

'Eleven-plus' school examination scores were obtained for 851 Birmingham children residing since birth in a lead-polluted area and 1642 children residing in two similar but unpolluted areas. It was found that the children in the lead-polluted area actually scored higher on the average than children in the control areas. Within the area of lead contamination, children living closest to the source of pollution did not have significantly lower scores than children living further away. The results indicate that lead pollution of the magnitude reported in this investigation did not have a demonstrable effect on the mental capabilities of children in the affected community.     

Amplified migration inhibition effect

Upon exposure to specific antigen in tissue culture, sensitive lymphocytes released macrophage migration inhibition factor and other lymphokines into the supernatant culture medium. Migration of peritoneal macrophages from nonsensitive animals was inhibited in the presence of such supernatants. However, with previous techniques it was found that an inhibitory effect was present at only low low titers (less than 10(2)). It is therfore of great interest that by increasing cellular density, the total number of cells being kept constant, inhibitory activity can be amplified by a factor as great as 10(10). This amplification was observed only when lymphocytes and macrophages were loosely packed, as by spontaneous sedimentation in a conical test tube. The effect was abolished by dispersing the cell suspension in a flat-bottomed flask or, alternatively, by shaking the test tube so that intimate prolonged intercellular contact was prevented.     

Frequency of the carrier state for X-linked chronic granulomatous disease among females with lupus erythematosus

Carriers for chronic granulomatous disease (CGD) and patients with lupus erythematosus (LE) share several characteristics: They are mostly females, they reduce nitroblue tetrazolium (NBT) poorly in their neutrophils, and, in some cases, they have similar skin lesions. We thus investigated 19 female LE patients for the presence of laboratory findings characteristic of the carrier state for CGD. None of these patients turned out to have the combined abnormality of neutrophil bactericidal activity and neutrophil NBT-reduction that is diagnostic of CGD carrier state in the X-linked form. An increased frequency of CGD carriers among female LE patients thus appear to be unlikely. Why some CGD carriers develop skin lesions typical of LE remains unexplained.     

Zinc therapy in acrodermatitis enteropathica

Albino Holtzman, albino Wistar and hooded HS rats were injected fortnightly for 14 weeks with human glomerular basement membrane (GBM) emulsified in Freund's complete adjuvant. Half of the rats were pretreated with Freund's complete adjuvant and some were unilaterally nephrectomized. Anti-GBM antibody glomerulonephritis, characterized by proteinuria (greater than 100 mg/16 h) and a diffuse linear deposition of host immunoglobulin along the glomerular basement membrane, was first detected in Holtzman rats 4 weeks after treatment with GBM had begun, and had developed in 69% of these rats by 15 weeks. In contrast, none of the similarly treated Wistar or HS rats became proteinuric at any time, although a few showed weak glomerular fluorescence at the end of the experiment. Thus Holtzman rats are susceptible, and HS and Wistar rats are resistant to experimental anti-GBM antibody glomerulonephritis. Pretreatment with Freund's complete adjuvant apparently shortened the induction period of the experimental disease in the Holtzman rats whereas unilateral nephrectomy appeared to decrease their susceptibility to it.     

Fungal products. Part XVII. Microbiological hydroxylation of gibberellin A9 and its methyl ester

Angiotensin II (A II) and analogues were tested for their ability to restore electrical and mechanical activity to cardiac muscle preparations in which the fast Na+ channels had been inactivated by partial depolarization (22-27 mM K+) or by tetrodotoxin (TTX). The partially depolarized or TTX-blocked preparations were chosen because under these conditions electrical and mechanical responses are primarily Ca2+ -dependent. In depolarized rabbit right atria, A II restored spontaneous mechanical and electrical activity (measured by both intracellular and extracellular recording techniques). The frequency of action potential discharge was concentration-dependent; the threshold concentration of A II was 10(-10) M, the ED50 was 8 X 10(-9) M, and the maximum effect was observed at 5 X 10(-8) M. In contrast, depolarized guinea pig atria were insensitive to A II, Sar1-angiotensin II, and des-Asp1-angiotensin II, even at concentrations as high as 10(-5) M. Rabbit papillary muscle (TTX-blocked), embryonic (18-day) chick heart (partially depolarized) and chick heart reaggregates (TTX-blocked) responded similarly to rabbit atria in that A II (9.6 X 10(-7) M) restored both electrical and mechanical activity. We found that in these preparations the action of A II was unaffected by propranolol (5.0 X 10(-6) M to 5.0 X 10(-5) M) but was blocked by Mn2+ (10(-3) M), D-600 (1 X 10(-7) g/ml) and the specific A II antagonists Sar1-Ala8-angiotensin II (P-113) (5.0 X 10(-5) M) and Sar1-Ile8-angiotensin II (5.28 X 10(-5) M). We conclude that the positive inotropic effect of A II on the myocardium is due to its ability to increase transmembrane ion movements in or through the cell membrane. The ability of Mn2+ and D-600 to block this effect suggests that this ion movement is via the so-called "slow channels."     

An electrophoretic analysis of RNA synthesis in normal and lobeless Ilyanassa embryo

A primary infection with schistosoma mansoni, of 5 or more weeks duration, stimulated a high level of resistance to a challenge infection in the WO outbred strain of golden hamster. In sharp contrast, the LGN strain showed no statistically significant immunity to reinfection in most experiments and where detected the level of resistance was only about half that observed in the WO strain. Immunity to reinfection was assayed with the lung recovery method which assesses resistance a few days after challenge and with the conventional perfusion assay which measures immunity 6 weeks after challenge. Wide differences in the immune response to S. mansoni in different strains of the same host species have not been reported previously.     

Regulation of nitrogen catabolic enzymes in chick liver -- effects of amino acids

It is well-known that in the chick, dietary protein increases the levels of several hepatic enzymes that are involved in nitrogen metabolism and excretion. However, the biochemical mechanism of this response is essentially unknown. The experiments presented in this paper show that the chick is responding to alpha-amino nitrogen and not to any specific amino acid. Furthermore, it is shown that this system responds to endogenous sources of nitrogen as well as dietary protein and that the xanthine dehydrogenase response involves regulation of enzyme synthesis without changing the rate of degradation.