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The history and development of pesticide regulation regarding active ingredients and formulated products used against vertebrate animals is described and discussed, from early efforts up to and through the 1947 passage of the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), as well as more recent developments and amendments. Discussion includes the development of pesticide labels and their importance.

The history of pesticide regulations is presented. Major emphasis is on federal regulations. The evaluation of avicides and rodenticides Is discussed and related to regulations. Currently registered avicides and rodenticides are described along with a listing of efficacy criteria requirements. The future of registration of avicides and rodenticides is projected.

Copyright of Wilhelm Roux' Archiv Für Entwicklungsmechanik Der Organismen is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A highly proteolytic Gram-negative, rod-shaped bacterium was isolated from the gills of fresh plaice and the effect of culture conditions on the production of proteolytic enzymes was investigated. When the organism, strain SA 1, was grown in the presence of complex mixtures of proteins and amino acids, both endopeptidase and aminopeptidase activity was demonstrated in the cell-free culture medium. However, synthesis of these enzymes was not observed when the organism was grown in a mineral medium with lactate or succinate as the only carbon and energy source. Synthesis of both endopeptidase and aminopeptidase was induced by the presence of amino acids in the medium. Of the amino acids tested, l-phenylalanine was found to be the best single inducer for the production of endopeptidase. When in addition one or more different amino acids were added, endopeptidase production was found to increase with increasing complexity of the mixture, up to a maximum which was obtained with five different amino acids. Production of the aminopeptidase was optimal when l-glutamic acid was used as a single inducer. For this enzyme the amount of enzyme activity released in the medium decreased with increasing complexity of the amino acid mixture. Endopeptidase as well as aminopeptidase activity was found to accumulate in the medium at the end of the logarithmic growth phase, when the culture was no longer growing exponentially. When the stationary phase was reached, enzyme production stopped. Production of both enzymes was immediately halted upon addition of chloramphenicol and was found to be repressed by glucose and lactate. These results suggest that synthesis of proteolytic extracellular enzymes by the organism studied is controlled by an efficient regulatory mechanism, in which growth rate is an important parameter. [ABSTRACT FROM AUTHOR]

The reversible equifinal state in the circulatory system was obtained in pentobarbital anesthetized dogs, cats and rats, by means of the intravenous injection of hexamethonium, with production of an autonomic blockade and a reduction of the systemic arterial pressure to about 50% of the initial value. Equifinality was also obtained in dogs after the cervical injection of lidocaine into the spinal canal; the functional exclusion of ponto-medullary cardiovascular centers also produced a decrease in arterial pressure. The reactivity of these dogs was studied during the occlusion (step function) of either the abdominal aorta or of both common carotid arteries and compared to the pressure responses during control periods. After the autonomic blockade with hexamethonium the normal increase in blood pressure observed after bilateral carotic occlusion was not present and the relative increase in blood pressure during aortic occlusion was not followed afterwards by the reflex decrease observed in control animals. The main differences between normal blood pressure regulation in the circulatory system under normal, or equifinal conditions are analyzed using hydraulic models, block diagrams and signal flow diagrams. From the present study it may be concluded that the mammalian circulatory system is able to accomplish the blood transport in the resting state, either with normal controls or in the equifinal condition, despite the fact that in the latter no autonomic regulations are present. [ABSTRACT FROM AUTHOR]

The problem of access control and privacy in computer systems is surveyed in terms of existing systems and current proposals. A review of suggested legal and administrative safeguards is given. The bulk of the discussion deals with the current technology, its limitations, and some additional safeguards which have been proposed but not implemented. Finally, a few promising computer science research problems in the field are outlined. A partially annotated bibliography of literature in the area is included. [ABSTRACT FROM AUTHOR]

Copyright of Pflügers Archiv: European Journal of Physiology is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Rats were given the opportunity to drink morphine solution following stabilization at three levels of 'passive premedication'. Compared to saline treated controls, premedicated rats consumed more morphine solution, but medication level did not significantly affect morphine intake. Premedicated rats adjusted to a reduction in morphine solution concentration by increasing fluid intake substantially, but nonpremedicated rats did not. When morphine was offered in a vehicle of isotonic saline oral consumption rose sharply in premedicated rats but not in their nonpremedicated counterparts. 'Drinker' and 'nondrinker' rats were identified on the basis of initial response to oral morphine. Premedication eliminated resistance to morphine drinking, but even at the expense of severe fluid deprivation, nonpremedicated nondrinkers refused morphine throughout the entire experiment. [ABSTRACT FROM AUTHOR]

In conscious dogs, blood flow in the circumflex branch of the left coronary artery was measured with electromagnetic flowmeters. Myocardial anoxia followed by reactive hyperemia was produced by occluding the artery with a pneumatic cuff for up to 120 sec. [ABSTRACT FROM AUTHOR]

Methods were developed for the determination of HMG CoA (3-hydroxy-3-methylglutaryl CoA) reductase activity in subcellular fractions of intestinal mucosa and liver of Wistar strain rats. In the liver, reductase activity was located exclusively in the microsomal fraction. In the intestinal mucosa, activity was found in both mitochondrial and microsomal fractions of crypt cells but not of villi. The microsomal HMG CoA reductases of liver and intestinal mucosa had similar kinetic characteristics and pH optima. However, the activity of the hepatic enzyme differed with age and sex of the experimental animals while that of the intestinal crypt cells did not. Cholestyramine treatment enhanced the activity of the microsomal HMG CoA reductase in both liver and intestinal mucosa. Reductase activity of the intestinal crypt cells was elevated in both jejunum and ileum. The greatest stimulation, both relatively and absolutely, was observed in the distal half of the jejunum.

The hepatic biosynthesis of bile salts in the rat has been shown to be controlled homeostatically by the quantity of bile salt returning to the liver via the portal circulation. The feedback mechanism was demonstrated in two kinds of experiments. In the first, rats with bile fistulas were infused intraduodenally with sodium taurocholate 12 hr after surgery. If the rate of infusion was greater than 10 mg per 100 g rat per hr, the increase in bile acid output normally observed in bile fistula rats was prevented. In the second type of experiment, the rats were infused with taurocholate 48-72 hr after biliary diversion, when bile acid output had reached a maximal value. Provided the rate of infusion exceeded 10 mg per 100 g rat per hr, bile acid secretion returned to the low levels observed in intact rats. Previous attempts to demonstrate the feedback control have been unsuccessful because too little bile salt was infused.The taurocholate pool of the experimental animals was measured as approximately 15 mg per 100 g rat; it was calculated from this and the above results that this pool circulated 10-13 times daily.