1. Nephrotoxic serum nephritis was induced in rabbits. 2. Treatment with Arvin to produce defibrination provided structural and functional protection to the glomeruli.Key words : nephrotoxic serum nephritis, Arvin.Administration of heparin before the induction of nephrotoxic serum nephritis in rabbits decreases the incidence of crescent formation and glomerular sclerosis (Halpern, Milliez, Lagrue, Fray 8c Morard, 1965). Anticoagulation with a dicoumarol also decreases the amount of intraglomerular fibrin deposition (Vassalli 8c McCluskey, 1964), and it has been postulated that fibrin deposition may be an important factor in the pathogenesis of some features of glomerular damage in this disease. It is known, however, that heparin has a number of other effects apart from that of anticoagulation, such as anticomplementary and histamine binding activity. Neither heparin nor dicoumarols directly inhibit the conversion of fibrinogen into fibrin but act at earlier stages in the coagulation cascade.To investigate the role of fibrin deposition more precisely, and eliminate, as far as possible, effects on other pathogenetic mechanisms, the circulating amount of fibrinogen in animals given the disease has been decreased to extremely low values by the intravenous administration of Arvin. This causes the intravascular formation of unstable fibrin polymers which are sequestered mainly in the lungs and reticulo-endothelial system and undergo rapid lysis with no apparent harmful effect on renal or other organ function. As the only significant effect of Arvin that has been shown to occur is one of defibrination, its effects on nephrotoxic serum nephritis may be expected to indicate only that part played by fibrin deposition in the pathogenesis of the glomerular damage. MATERIALS A N D METHODSThe experiment was divided into two parts: in each six treated and six untreated animals were used, The animals were New Zealand white rabbits weighing between 2 and 2.5 kg. They were
This study investigated the characteristics associated with smoking during pregnancy. A total of 7836 pregnant women were surveyed between 1992 and 1999 in England. Of these 27% were smoking during pregnancy. Pregnant women were more likely to smoke if they were less educated, living in rented accommodation, in unskilled manual or unemployed groups, and single or had a partner who smokes. Analysed by logistic regression, whether or not a pregnant women has a partner and, if so, his smoking status, was by far the biggest predictor of the pregnant woman's current smoking status. Thus, compared with women with partners who never smoke, the odds ratio (OR) of smoking during pregnancy for women with a partner who smokes was 2.3 (1.9-2.7) while those with no partner had an OR of 4.8 (3.8-6.0). For women exposed to passive smoke at home or at work the OR was 2.5 (2.1-3.0). Housing tenure was the most important socio-demographic predictor. Thus pregnant women living in rented council housing were nearly twice as likely (OR 1.93;1.63-2.29) as those buying their own home to be current smokers. The number of women who continued to smoke during pregnancy increased 10-fold from the least to the most deprived group. These findings highlight the importance of tobacco control strategies that address pregnant women's life circumstances and broader inequalities as well as those that focus on individual smoking behaviour.
Identifying, locating and interpreting both what is present and what is not present in theory and data lies at the core of scientific practice. Most experienced researchers know that social reality and psychological phenomena cannot always be apprehended directly, and that the forces that shape them must often be inferred rather than positively demonstrated. Yet, the important analytical problems raised by “absence” have rarely occupied the centre stage in professional journals. The aim of this paper is to sensitise researchers to the problem of absence. It considers the various guises in which absences may appear, their repercussions in the research process, and the solutions that researchers have used to render absences visible. The paper focuses on the issue of absence as it appears in theory and research on social representations. A typology of absence, structured in terms of the research process, is proposed. The typology is intended purely as a heuristic tool. It identifies and discusses forms of theoretical, methodological, empirical and analytical/interpretive absences. This typology is used to explore forms of absence and their interrelationships throughout the research process in three studies on social representations. The discussion as a whole contributes to reaffirming the radical character of the theory of social representations by stressing how the latter locates the space of explanation at the interface between individual and collective representations, between social and cognitive processes, between intentional and non‐conscious dynamics, and between material and symbolic realities.
The subcutaneous implantation of a cotton pellet in the rat evokes a short-lasting phase of increased capillary permeability lasting some 20 rnin. after implantation followed by a more sustained phase which occurs after 25-3 hr. The early increase is antagonised by lysergic acid diethylamide, reserpine and 5-HT. The peak granuloma weight is reached at 2 days, and then falls rapidly. Antagonism of oedema and granulation tissue by hydrocortisone and reserpine can be demonstrated at 2 days after implantation.
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