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The course of N-NO 3 concentrations in soil, N transfer from the catch crops Vicia sativa L. and Trifolium resupinatum L. to the companion grass Lolium multiflorum ssp. gaudinii (Parl.) Schinz et Keller, and the preceding crop effect on Lolium multiflorum ssp. italicum (A. Br.) Volkart were studied in a field experiment. Catch crops were sown in pure stands and grass/legume swards (= two species in alternating rows) at two sowing dates and harvested at different dates from August to November. Vicia sativa was more effective concerning N 2 fixation than Trifolium resupinatum, this was also evident from above ground N yield and N-NO 3 amount of the soil. The factor sowing date had the greatest influence on N yield. N transfer to the companion grass was generally low. Early sown legumes in pure stands and in mixture temporarily caused slightly increased N-NO 3 amounts in soil compared with unfertilized grass in winter and following spring, whereas late sown legumes apparently had no effect on N-NO 3 amounts. Both legumes had a considerable preceding crop effect in the mixture and in the pure stand for both sowing dates.

Purpose There is little information about exposure to dosages below 500 mSv. This pilot study aimed at investigating the effects of low dose radiation on lens transparency in occupationally exposed interventional cardiologists and radiologists. Methods Physicians who have performed fluoroscopically guided procedures for at least 5 years were recruited in the areas of Cologne-Bonn and Rhine-Main together with their non-exposed colleagues. A questionnaire has been developed to estimate occupational exposure. Exclusion criteria comprised corticosteroid treatment, radiotherapy, chemotherapy and glaucoma. Changes in lens transparency and cataract formation were determined by slit lamp microscopy including LOCS III grading, slit lamp photography and Scheimpflug/Pentacam® imaging. Results The prevalence of lens opacification mainly found in the nuclear region was 52% (95% CI: 30-74%) among interventional physicians and 31% (95% CI: 9-61%) among their non-exposed colleagues. Densitometric analysis of the cornea demonstrated a mean value 52,8% (SD: 7,4) in exposed participants compared to 45,9 % (SD: 7,2) in non-exposed colleagues. In the lenses layers 4 (deep cortex) and 5 (supra-nuclear layer) evidenced higher mean densities (40,5% (SD: 3,9%) vs. 31,6% (SD: 6,9%) in layer 4 and 27,5% (SD: 1,9%) vs. 23,7% (SD: 4,3%) in layer 5). Conclusion The data from the ophthalmological examinations demonstrated generally normal findings. However, classification of the mostly small cataracts and densitometric analysis of cornea and lens evidenced that low dosage exposure to ionizing radiation has an effect on corneal and lenticular transparency, albeit on a subclinical level.

Purpose Evaluation of the effects of different anti-diabetic therapies on light scattering in the lenses of type II diabetic patients compared to data from age-matched normal patients. Methods The anterior eye segment of 53 patients (20 males and 33 females, mean age 68,23 years) from a private practice, 25 of which were on insulin therapy and 28 on oral anti-diabetic therapies, were photographed with a Topcon SL-45 Scheimpflug camera on Kodak Tmax 400. After standard development the images were digitized and evaluated in respect to density in defined lens layers. Statistical comparison was performed with regression analysis between diabetics and normal patients for 9 defined lens layers. Results Density data in lens layers 1 – 3 and 5 – 8 did not differ between the 2 treatment groups, whereas in layer 4 (anterior lens cortex) light scattering was significantly lower than in the group of patients on oral anti-diabetic therapy. Gender had no influence on the data evaluated in this study. Conclusion In contrast to other, larger studies comparing different anti-diabetic therapies, this study shows a trend indicating that insulin might provide a better protection of lens crystallins against non-enzymatic glycosylation than oral anti-diabetic medication. Further studies are needed to differentiate between various oral anti-diabetic drugs.

1. Es ist gelungen, Mausecarcinome durch Allgemeinbehandlung der Tiere in einer Sauerstoffatmosphare unter erhohtem Druck zur Heilung zu bringen. 2. Diese Heilung ist unter den gewahlten experimentellen Bedingungen allein mit Sauerstoff moglich. 3. Das Resultat kann durch Kombination der Sauerstoffuberdruckbehandlung mit intravenoser Injektion von Kupfer- und Selenpraparaten verbessert werden. 4. Der Erfolg der medikamentosen Behandlung unter den gewahlten Bedingungen ist gebunden an die Kombination mit Sauerstoffuberdruckbehandlung. 5. Der Heilerfolg ist bisher durch ganz bestimmte Bedingungen begrenzt. Ob diese Grenzen uberwunden werden konnen und damit eine Therapie bosartiger Geschwulste uberhaupt erreicht werden kann, mus vorlaufig als durchaus zweifelhaft angesehen werden.

Die ubliche Messung des Wachstums von Gewebekulturen durch Bestimmung derFlache auf planimetrischem Wege entspricht nicht der Gewichtszunahme, stellt also keine brauchbare Methode zur Feststellung der tatsachlichen Massenzunahme von Gewebekulturen wahrend einer bestimmten Versuchsperiode dar.

Micrococcus radiodurans , a red-pigmented bacterium, is very resistant both to ionizing and to ultra-violet radiations. The dose-response curves in both cases are sigmoidal with high extra-polation numbers. Two non-pigmented mutants of M . radiodurans have been isolated. One of these shows the same type of survival curve as the wild type while the other has an exponential survival curve. Energy transfer reactions including the possible role of pigment have been excluded as a mechanism of resistance. Similarly, resistance is not due to unusual amounts or unique properties of the bacterial DNA . Survivors of both sensitive and resistant bacteria show a lag period following irradiation. In the case of sensitive bacteria no change occurs in the radiosensitivity of the cells during this period. On the other hand, M . radiodurans recovers during the lag period, at the end of which it has become as resistant as the unirradiated cells. All available evidence for the loss of viability in bacteria points to DNA as the target. Recovery of M . radiodurans from radiation damage, therefore, is concluded to be due to repair of damaged DNA by an active cellular, probably enzymic process which occurs during the lag period. The large shoulder of the survival curve and the high extrapolation number are a reflexion of the efficiency of the repair system. The significance of the sigmoidal and exponential survival curves of resistant bacteria is discussed and a theory put forward which postulates two types of damage to the genetic structures, each having a specific repair system. Some experimental evidence in support of this theory is produced.

Most of the work on the effect of fertilization on the metabolism of seaurchin eggs has been concerned with the average rate of O 2 consumption before and after activation. Although observations of this type are of interest, the changes which take place during the actual fertilization of the eggs are more indicative of the mechanisms responsible for the initiation of development. Technical difficulties have impeded experiments of this latter type. Early workers (Warburg 1915) found it necessary to fertilize the eggs before the beginning of the experiment, or, after measuring the O 2 consumption of unfertilized eggs, to open the manometer vessels to effect insemination. The former method precludes any measurements during the fertilization reaction, and the latter involves a period of manipulation and consequent re-equilibration which exceeds the duration of the fertilization reaction. When, therefore, it is stated that the O 2 consumption rate increases upon fertilization or parthenogenetic activation by some 200-400%, what is usually implied is that the O 2 consumption rate measured over a considerable period of time after insemination is some 200-400% more than the rate for a similar period of time before insemination. Shearer (1922) was the first to realize the importance of measurements immediately after insemination; 1 min. After insemination he observed an increase in O 2 consumption which was not maintained at the original high level. We have been unable to confirm Shearer’s results when using a similar method (see fig. 2). In recent years further attempts have been made (e. g. Runnström 1933 b ; Brook, Druckrey and Herken 1938) to make measurements immediately after fertilization by having the sperm inside the manometer vessel before fertilization but separate from the eggs; at a given moment sperm and eggs are mixed; but in these condition, the shortest time interval measured after insemination was 10 min. (Runnström), by which time the initial phase of the fertilization reaction is over.

DURING radiobiological work on bacteria it was found by one of us (H. L.) that the effect of ionizing radiation (X-rays) is greatly potentiated if the bacteria are irradiated in a medium in which water is replaced by heavy water1. Thus, for example, with Escherichia coli B and Pseudomonas 6009 the dose-reduction factor was approximately 2, that is, the X-ray dose required to produce a given reduction in the number of colony-forming bacteria on irradiation in deuterium oxide was one half that in water. This effect, however, occurred only if the bacteria were irradiated in presence of oxygen, but not, or only insignificantly, after irradiation under anaerobic conditions.