Influence of testosterone on pup killing in the rat is modified by prior experience.

The usual response of the adult male rat which is placed together with newborn rat pups for the first time is to kill and eat the pups. In past experiments castration of the male blocked this behavior, and replacement therapy with testosterone propionate (TP) maintained the behavior. In the present experiments this relationship between testosterone and pup-killing behavior was modified by giving the animals prior killing or nonkilling experience. In general, experienced killers continued to kill on a retest after 30 days of testosterone deprivation, and experienced nonkillers tended not to kill on the retest even though they were given daily treatment with testosterone for thirty days prior to retesting.     

Brain serotonin depletion by p-chlorophenylalanine or lesions of raphe neurons in rats

Male Sprague-Dawley rats were treated with p-chlorophenylalanine (pCPA) and 15–24 hr later their behavior was rated in an observation chamber. Their behavior was compared with rats which had lesions in the dorsal and median raphe nuclei to deplete brain serotonin. In spite of a comparable lowering of brain serotonin, lesioned rats did not display exaggerated sexual or aggressive behavior.     

Effect of potassium iodide and perchlorate on the secretion of thyroid hormones

The effect of potassium iodide and perchlorate was studied on parameters characterizing the secretion of thyroid hormones: the cyclic AMP level in the thyroid gland tissue and the number of intracellular colloid drops during stimulation with thyroid hormones. Excess of iodide was shown to depress these indices whereas perchlorate prevented the inhibitory effect of iodide. The results support the view that the adenylate-cyclase system of the thyroid gland is sensitive to the organic iodine concentration. Excess of iodide evidently reduces the ability of perchlorate to affect its concentration in the gland, so that the process of organification of iodine and the secretion of thyroid hormones are maintained at the optimal level.Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 86, No. 12, pp. 653–655, December, 1978.     

PCR扩增孕妇外周血DNA进行胎儿性别诊断

采用密度梯度离心技术对40例孕妇外用血中胎儿细胞进行富集,并用PCR技术扩增了Y染色体特异重复序列,以产前基因诊断胎儿性别,结果38例胎儿性别诊断准确,证明此技术可作为无创伤性方法用于X连锁遗传病的产前诊断.     

The Effects of Feedback Sensory Modality, Feedback Information Content, and Sex on Short-Term Biofeedback Training of Three Responses

In three factorial experiments, auditory vs visual vs tactile feedback, analog feedback vs analog feedback which was anchored, and sex, were varied to assess the effects of these variables on performance in short-term biofeedback training of heart rate reduction, hand temperature increase, and forehead muscle tension reduction. A total of 108 subjects served in the study. Moderate but reliable changes were found during the course of the training session for all three physiological responses. The ability to reduce heart rate in a single training session did not appear to be a function of any of the variables manipulated in this study, but rather could be attributed to adaptation. In both muscle tension and temperature training, however, there were significant interactions between sex and sensory modality of the feedback stimulus and, in the case of muscle tension training, between information content of the feedback signal and sex. The overall pattern of results indicated that performance during biofeedback training is a complicated function of sex and the type of signal used to provide feedback, and that this function is not constant across physiological response systems.     

Carcinoid Tumor of the Middle Ear Containing Serotonin and Multiple Peptide Hormones A Case Report and Review of the Pathology Literature

A 69-year old man complaining of longstanding hearing loss and mild otorrhea was found to have a mass obliterating the external auditory canal and polypous tympanic mucosa with accompanying absence of the tympanic membrane and ossicular chain. Tumors excised from the external auditory canal and tympanum showed histologic features essentially characteristic of a carcinoid tumor: a ribbon or festoon arrangement of tumor cells, formation of anastomosing cords and glandular spaces, presence of numerous argyrophilic as well as argentaffin secretory granules within many of the tumor cells, and ultrastructur-al evidence of neurosecretory granules in the tumor cell cytoplasm. Immunohistochemically, the tumor was found to contain not only neuronal marker substances such as neuron-specific enolase, S 100 protein and chromogranin A, but also serotonin and multiple peptide hormones such as pancreatic polypeptide, glucagon, cholecystokinin and leucine-enkephalin. A review of the pathology of 17 previous cases of carcinoid of the middle ear suggested that this type of carcinoid may have a variegated hormone profile among carcinoids of foregut origin, and hormonally may resemble ileal carcinoid arising from the midgut, although their histogenetic origins may differ, because of frequent production of serotonin. Acta Pathol Jpn 42: 614–620, 1992.     

Nocturnal hormonal responses to resistance exercise

The effects of resistance exercise on the nocturnal responses of cortisol (CO), testosterone (TEST), human growth hormone (hGH), and thyroid hormones (T₃, T₄) were examined in eight trained weight lifters. Each subject completed two trials using a counterbalanced design: a control, no exercise trial (CON) and a heavy resistance exercise session of three sets of six exercises to exhaustion (RE). The exercise session took place between 1900 and 2000 hours. Blood was sampled prior to and at 20-min intervals after RE. For both trials blood was sampled at hourly intervals from 2100 hours until 0700 hours. The hGH and CO concentrations were increased up to 40-min post-exercise (P < 0.05), but returned to resting levels 1 h post-exercise. Nocturnal hGH concentration was not affected by RE (P > 0.26) and peaked at 0200 hours and declined until 0700 hours. Similarly, the CO responses were similar between the trails (P > 0.14). This CO concentrations declined from 2200 hours until 0100 hours, then increased steadily until 0700 hours. The TEST concentrations during both trials rose steadily from 2200 hours until 0700 hours; however, the rise in TEST from 0500–0700 hours during RE was greater than during the CON trails (P = 0.059). The T₃ concentrations were unchanged by exercise and were similar at all times between trails. The T₄ concentrations were elevated for 20 min after RE; however nocturnal T₄ concentrations were lower after RE than during CON. These results would suggest that bGH and CO may have limited nocturnal reactivity to resistance exercise. However, the nocturnal alterations of TEST and T4 after resistance exercise, although small, may have implications for muscle anabolism.     

Time course for strength and muscle thickness changes following upper and lower body resistance training in men and women

 The purpose of this study was to investigate the time course of skeletal muscle adaptations resulting from high-intensity, upper and lower body dynamic resistance training (WT). A group of 17 men and 20 women were recruited for WT, and 6 men and 7 women served as a control group. The WT group performed six dynamic resistance exercises to fatigue using 8–12 repetition maximum (RM). The subjects trained 3 days a week for 12 weeks. One-RM knee extension (KE) and chest press (CP) exercises were measured at baseline and at weeks 2, 4, 6, 8, and 12 for the WT group. Muscle thickness (MTH) was measured by ultrasound at eight anatomical sites. One-RM CP and KE strength had increased significantly at week 4 for the female WT group. For the men in the WT group, 1 RM had increased significantly at week 2 for KE and at week 6 for CP. The mean relative increases in KE and CP strength were 19% and 19% for the men and 19% and 27% for the women, respectively, after 12 weeks of WT. Resistance training elicited a significant increase in MTH of the chest and triceps muscles at week 6 in both sexes. There were non-significant trends for increases in quadriceps MTH for the WT groups. The relative increases in upper and lower body MTH were 12%–21% and 7%–9% in the men and 10%–31% and 7%–8% in the women respectively, after 12 weeks of WT. These results would suggest that increases in MTH in the upper body are greater and occur earlier compared to the lower extremity, during the first 12 weeks of a total body WT programme. The time-course and proportions of the increase in strength and MTH were similar for both the men and the women. Accepted: 6 September 1999     

Sex- and age-related blood pressure response to dynamic work with small muscle masses

Summary Four groups of subjects of different ages and sex (group I: 20–29 years, women; group II: 20–29 years, men; group III: 30–39 years, women; group IV: 30–39 years, men) undertook dynamic one-hand work (load range 40%–80% of maximum voluntary contraction, at 60 working cycles/min) to allow a study of cardiovascular responses as shown by the resultant changes in blood pressure and heart rate. During fatiguing dynamic one-hand work, there was a large increase in systolic and diastolic blood pressures in both sexes after a few minutes. For all load levels, the systolic blood pressure was found to be higher by about 4 kPa in men (groups II and IV) than in women (groups I and III). Other age-related differences became evident in the diastolic blood pressure changes. The values obtained for the older groups were higher than those in the two younger groups. These differences in blood pressure response are possibly due to sex-related differences in the release of catecholamines, or to age-related organic changes in the vessels.     

Effect of treadmill exercise on food intake and body weight in lean and obese rats

Body weight and food intake of lean and obese, male and female Osborne-Mendel rats following treadmill exercise were compared. Rats were assigned, separately by sex, to one of three diet groups; Group 1 was fed a low fat (10%) diet throughout the study, Group 2 was fed a high fat (55%) diet for 16 weeks and then switched to the low fat diet 1 week prior to exercise, and Group 3 was fed the high fat diet throughout the study. To control for differences in work output between the leanest and heaviest animals, exercise intensity was adjusted across groups such that all exercised rats had equivalent energy expenditure. After a 3 day training period, the exercise was successively increased over 8 days until a work output of 374.9J was reached. Relative to their respective controls, obese exercised males showed a reduction in body weight but no change in food intake. In contrast, exercised females showed no change in body weight or food intake, regardless of dietary condition.