Interaction of salicylate and noise results in mortality of rats

Summary Survival as a function of salicylate dose and the intensity of environmental noise was investigated in 150 adult female pigmented rats. Rats were assigned to groups (n=6/group) defined by combinations of salicylate levels from 0- (saline) to 300 mg/kg, injected subcutaneously, and noise levels from ambient noise to 98 dB SPL, presented daily for 10-h periods for up to 17 days. Mortality occurred in groups exposed to the higher combinations of salicylate and noise.     

Genetic and environmental influences on reactive and spontaneous locomotor activities in rats

Paired groups of rats (derived from divergent, selective breeding or living in divergent environmental conditions) were compared with regard to locomotor activities. Intrapair differences were found to vary non-systematically, depending upon whether the rats were initially exposed to a test-environment with or without a slight environmental modification (reactive activities), or were allowed to habituate extensively to the environment (spontaneous activity). Since the behavioral patterns were found to represent distinct entities, this pointed to the necessity of differentiating clearly between spontaneous and reactive activities and indicated, once again, that both genetic and environmental influences are important in these behaviors and must be taken into account. Accepting and controlling for these variables makes it possible to use the factor of individual differences in laboratory animal behavior to advantage.     

Renal response to acute saline loading in Sabra hypertension-prone and-resistant rats

Summary The renal handling of an oral isotonic saline load was studied in hypertension-prone (SBH), hypertension-resistant (SBN) and the parental Sabra (SB) rats. The diuretic and natriuretic response of SBH rats was unequivocally diminished, thus lending further support to the concept of impaired salt handling in hypertension.This work was supported in part by a grant from Bayer AG, FRG.     

2．4-6．0GHz超宽带低噪声放大器的设计

采用标准0．5μmGaAsPHEMT工艺设计了工作频段在2．4—6GHz可应用于无线局域网（WLAN）和超宽带（UWB）接收机的超宽带低噪声放大器。从宽带电路的选择、高频电路设计的器件选择和电路结构的选择等方面讨论了如何进行超宽带低噪声放大器的设计。结果表明,通过合适的电路结构和器件参数选择,可以采用0．5μmGaAsPHEMT工艺制备满足超宽带系统要求的低噪声放大器。在UWB3．1～5．15GHz低频带内,该LNA增益20．8～21．6dB,噪声系数低于0．9～1．1dB,输入输出驻波比均小于一10dB。在2．4～3GHz频带（涵盖802．11b／g的使用范围）内,该LNA增益20．8～21．5dB,噪声系数低于2dB,输入输出驻波比均小于-10dB。在频带5．2—6GHz,该LNA的噪声系数增大到1．332dB。增益则从21．4dB下降到19．7dB。电路的工作电压为3．3V。     

Chronic maintenance of rat sperm reserves into old age by previous sexual contact

Summary Extensive copulatory experiences at a younger age provoked chronic changes in the reproductive physiology of old male rats. Continuous access to females was not necessary, sperm numbers were elevated in the 22-month-old males 7 months after a final sexual interaction.     

Antidiuretic effects of oxytocin in the Brattleboro rat

Summary The antidiuretic activity of oxytocin (OT) was measured in Brattleboro rats with congenital diabetes insipidus. A dose dependent antidiuretic response was found in animals receiving chronic infusions of 0.1 g/h, 1.0 g/h, and 5 g/h of OT. OT infused at the rate of 5 g/h over a 7-day period completely reversed the symptoms of diabetes insipidus. The results support the concept that OT serves as a weak agonist of vasopressin at the level of the kidney and at pharmacological levels exhibits antidiuretic activity.     

A Flexible Functional Form Approach To Mortality Modeling: Do We Need Additional Cohort Dummies?

The increasing amount of attention paid to longevity risk and funding for old age has created the need for precise mortality models and accurate future mortality forecasts. Orthogonal polynomials have been widely used in technical fields and there have also been applications in mortality modeling. In this paper we adopt a flexible functional form approach using two‐dimensional Legendre orthogonal polynomials to fit and forecast mortality rates. Unlike some of the existing mortality models in the literature, the model we propose does not impose any restrictions on the age, time or cohort structure of the data and thus allows for different model designs for different countries' mortality experience. We conduct an empirical study using male mortality data from a range of developed countries and explore the possibility of using age–time effects to capture cohort effects in the underlying mortality data. It is found that, for some countries, cohort dummies still need to be incorporated into the model. Moreover, when comparing the proposed model with well‐known mortality models in the literature, we find that our model provides comparable fitting but with a much smaller number of parameters. Based on 5‐year‐ahead mortality forecasts, it can be concluded that the proposed model improves the overall accuracy of the future mortality projection. Copyright © 2016 John Wiley & Sons, Ltd.     

Distal axonopathy in streptozotocin diabetes in rats

Summary We noted the earliest morphological changes in the motor endplates 8 weeks after the induction of streptozotocin diabetes in rats. Morphometric measurements showed reduced axonal areas of the lateral plantar and the sicatic nerves in the diabetic rats 28 but not 2 and 8 weeks after the experiment. These findings suggested distal axonopathy.     

Bombesin promotes pancreatic growth in suckling rats

Summary The pancreatic growth promoting effect of long term administration of bombesin was investigated in suckling rats. The authors showed that bombesin given in 10 g/kg b.wt doses s.c. every 8 h for 10 days from the day of parturition stimulated pancreatic growth: it increased pancreatic weight, protein and DNA content, trypsin and amylase activity and trypsin/DNA ratio. Conclusion: Bombesin is an effective stimulator of pancreatic growth in suckling rats.     

Dietary induced increase of lactase activity in adult rats is independent of adrenals

Summary Adult rats fed 10 days a low starch-high fat diet were either adrenalectomized or sham-operated and force-fed the same diet another 5 days; 14 h before sacrifice, some animals were force-fed a sucrose diet. Activity of lactase, sucrase and maltase was increased in adrenalectomized and sham-operated rats.Supported by the National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland, USA (AM 27624).     

Rate of tryptophan hydroxylation in vivo in brain nuclei of genetically hypertensive rats of the Lyon strain

Summary The rate of tryptophan hydroxylation in vivo is unaltered in brain areas of 5, 9 and 21 week-old Lyon genetically Hypertensive (LH) rats as compared to both Lyon Normotensive (LN) and Low Blood Pressure (LL) rats, except for a decrease in the C1 area of the medulla oblongata in 9 week-old animals.Acknowledgment. The authors wish to thank Dr M.F. Belin, Dr J.F. Pujol and Mrs J. Sacquet for their help during this study. This work was supported by the Fondation pour la Recherche Médicale Française and the C.N.R.S.     

Effects of blood sampling,anesthesia and surgery on plasma vasopressin concentration in rats

The influence of blood sampling, anesthesia and surgery on plasma vasopressin concentration was assessed in rats. Mean plasma concentration in conscious, chronically catheterized rats was 1.4±0.1 pg/ml (n=6). This value remained constant over repeated plasma samplings in the same animals. On the other hand, decapitation increased the plasma vasopressin concentration to 6.0±2.4 (in pg/ml) (n=6), inactin anesthesia to 2.9±0.6 (n=6), anesthesia and femoral cannulation to 13.3±5.8 (n=6) and surgery for renal micropuncture to 81.3±35.0 (n=6). It is concluded that the level of circulating plasma vasopressin is highly dependent on the sampling technique and is closely related to the extent of surgery.     

The impact of climate change on human health: Some international implications

The objective of this study is to discuss the potential impact of a global warming on various aspects of human health. Changes in heat-related mortality are estimated for four countries: the United States, Canada, the People's Republic of China and Egypt. In addition, the potential confounding impact of increased air pollution is considered. Finally, a framework to analyze two vector-borne diseases, onchocerciasis and malaria, which may spread if temperatures increase, is discussed. Our findings suggest that heat-related mortality is estimated to rise significantly in all four countries if the earth warms, with the greatest impacts in China and Egypt. The most sensitive areas are those with intense but irregular heat waves. In the United States, air pollution does not appear to impact daily mortality significantly when severe weather is present, although it seems to have a slight influence when weather conditions are not stressful.     

Toxic effects of methylmercury on spermatozoa in vitro

Summary In an in vitro investigation, methylmercury (MeHg) reduced the motility of rat spermatozoa probably by the inhibition of succinate dehydrogenase and ATPase activities. Concomitant morphological changes observed in the spermatozoa were coiled tails and kinks in midpiece and tail regions.     

Effects of progesterone and estradiol benzoate on superoxide dismutase activity in the brain of male rats

The activities of mitochondrial, manganese-containing superoxide dismutase (MnSOD) and cytoplasmic, copper-zinc-containing superoxide dismutase (CuZnSOD) were measured in subcellular fractions of whole brain homogenates prepared from intact and gonadectomized (GDX) male rats, untreated or treated subcutaneously (sc) with a single dose of 2 mg progesterone (P) and/or 5 g estradiol benzoate (EB). Neither MnSOD nor CuZnSOD was affected by the removal of the testes. Similarly, CuZnSOD activity was steady following systemic administration of P and/or EB to intact and GDX animals 2 h or 24 h prior to sacrifice. On the other hand, both P and EB suppressed MnSOD in the brain of either intact or GDX rats. These results suggest involvement of P and EB in the control of MnSOD activity in the brain of male rats.