TESTOSTERONE-INDUCED CELL PROLIFERATION IN THE ACCESSORY SEX GLANDS OF MICE AT VARIOUS TIMES AFTER CASTRATION

The proliferative response to testosterone in the accessory sex glands (seminal vesicle and coagulating gland) of castrated male Balb/c mice has been examined by pulse and continuous thymidine-labelling experiments, and by the fraction of labelled mitoses technique. Progressive reductions in cellularity followed castration, and by varying the time elapsing between castration and the initiation of testosterone treatment, it was clear that the size of the response depended upon the number of cells in the tissue, relative to the normal complement. Interpretation of FLM data was difficult in periods where proliferative rates changed rapidly. We have attempted to explain the cell kinetic events by postulating a G₀ compartment, from which cells are stimulated to enter the proliferative cycle before subsequently returning to an out of cycle state. It was thought unlikely that substantial changes in cell cycle time occurred. In both the accessory sex glands, the overall form of the continuous thymidine labelling curves showed that most proliferative cells entered DNA synthesis in a shorter time after stimulation at 14 days after castration than they did at 3 days after castration. The data were not consistent with cells moving deeper into G₀ with time after castration. In the seminal vesicle almost all epithelial cells were potentially proliferative by 3 days after castration. In the coagulating gland only 30% were potentially proliferative at 3 days, increasing to 85% at 14 days after castration. However, such proportional increases represented much smaller changes in terms of absolute numbers of cells, because of a concomitant decline in cellularity from 3 to 14 days after castration.     

The action of the adenosylhomocysteine hydrolase inhibitor, 3-deazaadenosine,on phagocytic function of mouse macrophages and human monocytes

An inhibitor of adenosylhomocysteine hydrolase, 3-deazaadenosine, caused profound inhibition of phagocytosis of opsonized erythrocytes by mouse resident peritoneal macrophages $\text{in}\text{vitro}$. The inhibition was evident at concentrations as low as 2×10^?7M, and increased with increasing concentration and time of exposure to the analogue. It was not associated with detachment of the macrophage monolayers or with loss of cell viability. Although the inhibition was not reversible, progression of the functional impairment was interrupted by washing out the analogue. In striking contrast, phagocytic function of human blood monocytes was unaffected by 3-deazaadenosine.     

Preliminary observations on the birth and development ofPropithecus verreauxi to the age of six months

In this paper, preliminary observations are presented on the ontogency of one of the Malagasy prosimians,Propithecus verreauxi. Observations were carried out in the course of an eighteen-month study of the social organization and ecology of four, free-ranging groups. Parturition is described, together with data on the development of locomotor and feeding behavior, and on the changing nature of the infant's relationship with its mother and with other members of the group. The final section compares the results of this study with those of previous studies ofP. verreauxi and other lemur species. Tentative conclusions are drawn concerning aspects of social ontogeny inP. verreauxi and areas for future research are suggested which would clarify some of the remaining problems.     

Inhibition of prostaglandin biosynthesis by sulphasalazine and its metabolites

Sulphasalazine (SZ) inhibits prostaglandin (PG) biosynthesis $\text{in vitro}$ with a potency comparable to that of aceylsalicylate. The metabolites of SZ, sulphapyridine and 5-aminosalicylic acid, were of considerably lower potency as inhibitors of PG biosynthesis in the synthetase preparations used. The inhibition of prostaglandin production by SZ could at least partly account for the clinical utility of sulphasalazine in ulcerative colitis. Sulphapyridine may help to maintain inhibitory concentrations of SZ by restraining bacterial breakdown of the active drug.     

Proton magnetic resonance relaxation studies on the structure of mixed micelles of Triton X-100 and dimyristoylphosphatidylcholine.

Proton magnetic resonance and gel chromatographic studies on mixtures of phospholipid and the nonionic surfactant Triton X-200 have shown that at temperatures above the thermotropic phase transition of the phospholipid and below the cloud point of Triton, mixed micelles are present at molar ratios above about 2:1 Triton/phospholipid. Proton T1 and T2 (from line widths) relaxation times are reported for protons in Triton micelles and in mixed micelles of Triton and dimyristoylphosphatidylcholine at a molar ratio of 3:1 Triton/phospholipid. The T1 values and their temperature dependence and the activation energies of the various Triton proton groups appear to reflect internal motions of the Triton molecules in the micelle. Measurements of the T1/T2 ratio and frequency dependence (55-220 MHz) suggest that the hydrophobic tert-butyl group in Triton is observed under extreme narrowing conditions. The T1 and T2 values of Triton are unchanged in the presence of phosphatidylcholine. The T1 values of various protons of dimyristoylphosphatidylcholine in mixed micelles are similar to those reported for the phospholipid in sonicated vesicles, which are used as membrane models, and presumably the same coupled trans-gauche motions dominate. The T2 values for the terminal methyl and choline methyl protons in the phospholipid are longer than those reported for these groups in vesicles. Hence, the motion of the phospholipid in the mixed micelles appears to be less restricted than in vesicles. T1 measurements in H20/D20 mixtures are consistent with the idea that water does not penetrate the hydrophobic core of the mixed micelles, while water does solvate the polar oxyethylene and choline methyl groups. Titration with Mn2+ confirms that the oxyethylene and choline methyl groups are on the exterior of the mixed micelle while the hydrophobic groups are located in the micellar interior.     

Structural and ecophysiological adaptations to forest gaps

To survive new microclimatic conditions of a forest gap environment, plant species must physiologically and structurally adjust. A morpho-anatomical, ultrastructural and ecophysiological study was performed at three different times in a forest gap that was created by illegal selective logging. The study followed the early successional Actinostemon verticillatus and the late-successional Metrodorea brevifolia, to elucidate the adaptive strategies of acclimation to gaps. Additionally, Schinus terebinthifolius was included in the study in order to test the plasticity of a pioneer species that grows on forest edges, where this species had higher values of leaf thickness, leaf mass area and succulence. M. brevifolia had succulent leaves, high leaf area and a thin cuticle. A. verticillatus presented the densest leaves and was the only species to show leaf morpho-anatomical plasticity. Ultrastructural and physiological differences were observed only in A. verticillatus and M. brevifolia leaves from the gap: increase in the stroma volume, oil droplets, plastoglobuli, photochemical and non-photochemical quenching. Photosynthetic efficiency showed that the early stages of gap formation are the most critical. Acclimation strategies of A. verticillatus suggest this species invests in the efficiency of photosynthesis by increasing its leaf thickness, leaf mass area and in water content maintenance by increasing the density of its leaves, at the expense of gas exchange, was compensated by a high density of stomata. M. brevifolia compensates for the higher cost of leaves and lower leaf plasticity with ultrastructural changes that are used to adjust the photosynthetic process, which promotes a shorter leaf payback time.     

Molecular Epidemiology of Carbapenem Non-Susceptible Acinetobacter baumannii in France

Carbapenem-resistant Acinetobacter baumannii have emerged globally. The objective of this study was to investigate the epidemiology, clonal diversity and resistance mechanisms of imipenem non-susceptible A. baumannii isolates in France. Between December 2010 and August 2011, 132 notifications were collected, including 37 outbreaks corresponding to 242 cases (2 to 55 per cluster). Multilocus sequence typing, pulsed-field gel electrophoresis (PFGE) and characterisation of carbapenemase-encoding genes were performed on 110 non-repetitive isolates. Gene bla _OXA-23 was the most frequently detected (82%), followed by bla _OXA-24 (11%) and bla _OXA-58 (7%). Eleven sequence types (ST) were distinguished, among which sequence types ST1, ST2 (64%), ST20, ST25, ST85 and ST107. Isolates from epidemiological clusters had the same ST and resistance genes, indicating probable transmission within centres. In contrast, PFGE types of isolates differed among centres, arguing against transmission among centers. This study provides the first epidemiological snapshot of the population of A. baumannii with reduced susceptibility to carbapenems from France, and further underlines the predominance of international clones.