The influence of nitrate on the induction of nitrate reductase in maize roots

A concentration of 10 mM NO3 saturates the induction of nitrate reductase in maize root tips whereas concentrations up to 100 mM do not saturate the induction in mature root sections. Increasing concentrations of nitrate from 1 to 25 mM have no effect on either the lag phase, or the phase of rapid increase of the enzyme. They do influence the final level of enzyme obtained at 8 h.

Cryptogenic drop attacks: an affliction of women

A drop attack was defined as falling without warning, not apparently due to any malfunction of the legs, not induced by change of posture or movement of the head, and not accompanied by vertigo or other cephalic sensation. All 33 patients attending a neurological clinic with a primary complaint fulfilling these criteria were women, and a further seven examples were found by questioning 200 consecutive patients at a gynaecological clinic. No affected male was found.In all but one patient, falls occurred only when walking. They were not due to wearing high-heeled shoes. The average age at onset was 44.5 years and in younger women onset was often during pregnancy. The accepted causes of drop attacks were not found with certainty in any of these patients. The sex incidence and the circumstances of the falls suggest that the cause may lie in differences between the two sexes in the mechanism of walking rather than in any central disturbance. Drop attacks in women commonly occur as an isolated symptom for many years, and although distressing have no serious prognostic implications.

Investigation of the responsiveness of BCG-vaccinated children with whooping-cough to tuberculin

Of 29 BCG-vaccinated children with a clinical diagnosis of pertussis, only 4 (14%) were found to be tuberculin positive. This is in marked contrast to the high rate of reactivity reported for normal BCG-vaccinated children of similar age. The 4 positive reactors did not differ significantly from the 25 negatives with respect to age, interval between onset of pertussis and tuberculin test, nor to lymphocyte count taken either as the absolute number or as the percentage of leukocytes. Possible mechanisms to account for this anergic state are discussed.

Measurement of human postural sway

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Investigation of cutaneous histamine sensitivity in children with pertussis

Enhanced sensitivity to histamine of children with pertussis has been the basis for speculation regarding similarities of receptor sites among the limited species of mammals said to be hypersensitive, and regarding the desirability of eliminating histamine-sensitizing factor from conventional pertussis vaccines. However, significantly enhanced sensitivity to i.e. injected histamine could not be demonstrated in a group of 6 children with pertussis compared to 4 controls.

Impotence in farm workers using toxic chemicals

Four out of five members of a team of farmworkers who had been using various herbicides and pesticides in intensive agriculture became impotent. Sexual function recovered after further contact with the chemicals was stopped and hormone therapy had been given, though in one case this took about a year. We have not been able to incriminate one particular substance, but with the circumstantial evidence and the lack of any other obvious cause it seems likely that the impotence was due to the toxic effects of one or more of the chemicals being used.

Alterations in lumbar cerebrospinal fluid protein during air encephalography

A significant fall occurred in the protein content of successive specimens of lumbar cerebrospinal fluid (C.S.F.) withdrawn during the course of air encephalography in 57% of cases. No correlation was found between the fall in the protein concentration and the total volume of air injected or the total volume of C.S.F. withdrawn, but the size of the fall was greater when the initial lumbar C.S.F. protein concentration was raised. The importance of taking specimens for routine laboratory analysis before the injection of any air is emphasized.

Progressive myoclonus epilepsy without Lafora bodies

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Origin of cyanide in cultures of a psychrophilic basidiomycete

An unidentified psychrophilic basidiomycete used valine and isoleucine as precursors to hydrocyanic acid (HCN). As probable intermediates in the pathway from valine and isoleucine two cyanogenic glucosides, linamarin and lotaustralin, were demonstrated in fungus cultures. The fungus contained two beta-glucosidases and an oxynitrilase which, acting together, were capable of releasing cyanide from both linamarin and lotaustralin. The two beta-glucosidases were purified and compared as to pH optimum, Michaelis constant, energy of activation, thermal stability, and substrate specificity. The products of methyl ethyl ketone cyanohydrin and acetone cyanohydrin dissociation by the oxynitrilase were demonstrated to be HCN together with methyl ethyl ketone and acetone, respectively. The oxynitrilase attacked aliphatic hydroxynitriles, but showed no activity on aromatic hydroxynitriles.