The structure and uses of the edinburgh remote terminal emulator

Remote Terminal Emulation is an approach to the testing and evaluation of multi-access computer systems in which a workload driver is implemented external to and independent of the system being tested. Remote Terminal Emulators may be used in many stages of system development, e.g. initial checkout, acceptance tests and tuning. The Edinburgh Remote Terminal Emulator (ERTE) is a system designed to exert a specified interactive workload on a multi-access system such that it appears to the system that it is connected to live terminal devices. The emulator runs on a PDP 11/40 computer under the control of the DEIMOS operating system, which like the emulator is written in the high-level language IMP. We describe the structure and development of ERTE with particular emphasis on its modularity, the use of a message-based operating system and the IMP language, which provide a flexible and easily modified tool. Experiments, both current and projected, using ERTE are discussed and our experience of developing and using a terminal emulator is reviewed.     

Glutarate semialdehyde dehydrogenase of Pseudomonas. Purification, properties, and relation to L-lysine catabolism

The lysine-induced glutarate semialdehyde dehydrogenase of Pseudomonas was purified to electrophoretic homogeneity from a mutant strain lacking delta-aminovalerate transaminase. The properties of the enzyme, including molecular weight, amino acid composition, electrophoretic behavior, and kinetic features, distinguish it from similar dehydrogenases induced in the same cell strain by hydroxyproline or by glucarate. Enzyme induction patterns and the growth behavior of a mutant deficient in glutarate semialdehyde dehydrogenase clearly relate this enzyme to the so-called delta-aminovalerate pathway of L-lysine catabolism. Induction studies also indicate that delta-aminovalerate is a better inducer of the dehydrogenase than L-lysine. Cells of a mutant strain lacking delta-aminovalerate transaminase contained higher levels of the dehydrogenase, presumably as a result of the accumulation of delta-aminovalerate, making this mutant a useful preparative source of the enzyme. The marked reduction of lysine-inducible glutarate semialdehyde dehydrogenase in a mutant strain permitted assessment of the basal levels of hydroxyproline/glucarate-inducible ketoglutarate semialdehyde dehydrogenases not possible in wild type cells.     

Strain differences in histopathologic, hematologic, and blood chemistry changes induced in mice by a technical and a purified preparation of 2,4,5-trichlorphenoxyacetic acid

Including controls, 978 mice were studied. On days corresponding to days 6 through 14 of pregnancy, groups of pregnant and nonpregnant CD-1 mice and male and nonpregnant female dihybrid cross F2 mice received by gavage 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) ranging in dosage from 30 to 140 mg/kg. Some groups received a technical preparation containing 97.9 +/- 0.4% 2,4,5-T and some a purified preparation containing 99 +/- 0.3% 2,4,5-T. Mice were sacrificed when they became moribund and at 1, 2, 4, 6, 8, and 11 days after beginning treatment. Sick or moribund mice sacrificed after 2-9 doses of 2,4,5-T often showed severe myocardial lesions, hypocellularlity of the bone marrow, and depletion of lymphocytes in the thymus, spleen or lymph nodes. They also showed marked hematologic and blood chemistry changes. Treated mice remaining healthy showed few or no lesions or blood chemistry changes, but often developed a mild anemia attributable to a hemolytic effect of 2,4,5-T. The incidence of animals becoming moribund was less than 1% in the CD-1 mice, including those given 140 mg/kg, and 53-82% in groups of male and female F2 mice receiving 120 mg/kg 2,4,5-T. The incidence of moribund mice tended to be higher in male than in female F2 mice and in those given the purified compound. These findings indicate that impairment of maternal health by severe lesions early in gestation is not the primary cause of an increase in incidence of fetal abnormalities observed in mice given 2,4,5-t. they also indicate that the lesions are due primarily to 2,4,5-T, rather than contaminants in the technical preparation, and illustrate the importance of using more than one strain of mouse in a toxicologic or teratologic study.     

Lipids of free-living Penecurva sibirica turbellaria

Lipids were extracted from the lyophylized free-living planariae P. sibirica according to the procedure of Folch et al. [14] and fractionated by means of thin-layer and column chromatography on the silicagel KSK. Total lipid content of planariae is equal to 28.70% of lyophylized weight, 21.70% of them being presented by phospholipids. Polar lipids include phosphatidylethanolamine, phosphatidylcholine, sphingomyelin, lysophosphatidylcholine and cerebrosides. Neutral lipids are presented by triglycerides, cholesterol cholesterol esters and free fatty acids. Saturated and unsaturated C6--C22 fatty acis were detected in the lipids.     

The secretion of citrate into milk

1. The time course of changes in specific activities of citrate, lactose and fatty acids in milk during frequent milking, following the I.V. administration of labelled glucose, acetate and chylomicrons in goats has been studied. Peak specific activities of lactose and citrate in milk were reached at 2-3 hr, while peak specific activites of fatty acids were reached at 5-7 hr. 2. Following short I.A. infusions of 24Na, 36Cl, and 42K, peak specific activities in milk were reached in 1 hr or less. 3. The mammary epithelium of lactating goats was found to be virtually impermeable to labelled citrate in both directions. 4. Labelled citrate had an apparent volume of distribution in lactating guinea-pigs mammary slices in vitro similar to that of extracellular space markers. 5. Treatment of goats with large doses of oxytocin markedly increased the permeability of the secretory epithelium to labelled citrate. 6. In the goat mammary gland, citrate, protein and calcium failed to enter milk which had been diluted with isosmotic lactose by intraductal injection, whereas Na, K and Cl did enter, thus tending to restore the concentrations of these ions to normal. 7. It is suggested that citrate, which is formed within the sucretory cell, enters milk not by passage across the apical cell membrane but, in common with lactose and milk protein, by exocytosis of Golgi vesicles. It appears that citrate is held at high concentrations in milk by virtue of the impermeability of the mammary epithelium to the forms in which it occurs in milk.     

Diverticulation of the cerebral ventricles: a cause of progressive focal encephalopathy

Diverticulation of the lateral ventricles of the brain has received little attention in the literature on hydrocephalus. From clinical observations on one child and one adult with diverticulation, it is apparent that force of CSF within the diverticulum is greater than that against the normal parts of the ventricular wall. In both cases, regression of focal symptoms occurred after insertion of a shunt.