Hormonal regulation mechanisms during puerperium

The regulation of the hypothalamic-hypophyseal-ovarian axis during puerperium is reviewed. The lactotrophic hormone prolactin is necessary for the growth of the milk producing system, initiation and maintenance of lactation. Inappropriate responsiveness of the hypothalamic-hypophyseal-ovarian system causes independent of the actual prolactin serum values postpartum amenorrhea during early puerperium. However, the duration of amenorrhea depends on the duration of breast-feeding. The prolactin peaks induced by suckling interfere with the reappearance of normal cyclic ovarian regulation.     

Hormonal changes during parturition in heifers and goats are related to the phases and severity of labour

BACKGROUND: Although the literature on increased physical fitness and psychological outcomes has grown large, a number of methodological limitations remain unaddressed. The present study was designed to address a number of these limitations while examining the short- and long-term psychological effects following completion of a 12-week aerobic fitness program using bicycle ergometry (and confirmed increases in fitness). METHOD: Following completion of a 12-week aerobic fitness program (and through 12 months of follow-up), 82 adult participants completed the Beck Depression Inventory, Profile of Mood States, State-Trait Anxiety Inventory, and the Tennessee Self-Concept Scale. Physiological measures used to assess changes in aerobic fitness were maximal work load, submaximal heart rate at a standard work load, predicted maximum oxygen uptake, and resting heart rate. RESULTS: Exercise participants experienced a positive fitness change and psychological improvement over the initial 12-week program compared to a control group. At 1 year follow-up, physiological and psychological benefits remained significantly improved from baseline. CONCLUSIONS: Overall, results indicate that exercise-induced increases in aerobic fitness have beneficial short-term and long-term effects on psychological outcomes. We postulate that participants in the exercise group did not increase the amount of weekly exercise they performed over the 12-month follow-up period and thus the maintenance of the psychological improvements occurred concurrent with equal or lesser amounts of exercise.     

Viscosupplementation with hylan G-F 20: a 26-week controlled trial of efficacy and safety in the osteoarthritic knee

Cortical color blindness, or cerebral achromatopsia, has been likened by some authors to "blindsight" for color or an instance of "covert" processing of color. Recently, it has been shown that, although such patients are unable to identify or discriminate hue differences, they nevertheless show a striking ability to process wavelength differences, which can result in preserved sensitivity to chromatic contrast and motion in equiluminant displays. Moreover, visually evoked cortical potentials can still be elicited in response to chromatic stimuli. We suggest that these demonstrations reveal intact residual processes rather than the operation of covert processes, where proficient performance is accompanied by a denial of phenomenal awareness. We sought evidence for such covert processes by conducting appropriate tests on achromatopsic subject M.S. An "indirect" test entailing measurement of reaction times for letter identification failed to reveal covert color processes. In contrast, in a forced choice oddity task for color, M.S. was unable to verbally indicate the position of the different color, but was surprisingly adept at making an appropriate eye movement to its location. This "direct" test thus revealed the possible covert use of chromatic differences.     

pH changes in root dentin over a 4-week period following root canal dressing with calcium hydroxide

An immunofluorometric method was developed for the semiquantitative determination of trihexosylceramide in cultured fibroblasts from Fabry disease patients, using a laser scanning confocal imaging system. The accumulated glycolipid was detected as granular inclusions in the cells. Heterozygote identification was achieved both by counting of immunoreactive cells and by measuring the relative fluorescence intensity with a digital imaging system.     

Reversible and irreversible length changes in amorphous Fe40Ni40B20 during structural relaxation

Measurements are presented of the isothermal and isochronal change of length during structural relaxation of amorphous Fe₄₀Ni₄₀B₂₀. The observed changes in length can be separated in three contributions:

• 1.(1) An irreversible part with a well denned activation energy of 250 kJ/mol, which is well described by the free volume model.
• 2.(2) A relatively small reversible part in the activation energy range from 210 to 250kJ/mol and with a magnitude of about 0.4ppm/K. This is ascribed to Chemical Short Range Ordering.
• 3.(3) An irreversible part in the activation energy range from 130 to 250 kJ/mol, with a magnitude of about 800 ppm in as-quenched specimens.

It is shown that the length isothermals of as-quenched specimens, after correction for the free volume contribution, can be scaled to form a “masterplot”.     

Hormonal secretion during nighttime sleep indicating stress of daytime exercise

We tested the hypothesis that long-duration exercise (LDE) of moderate intensity, but not LDE of low intensity, during the daytime changes the typical temporal patterns of hormone release during subsequent nocturnal sleep. Ten trained healthy men participated in a balanced crossover study including three conditions: 1) no exercise, 2) LDE of low intensity (biking 40 km; 1800-2030), and 3) LDE of moderate intensity (biking 120-150 km; 1600-2030). During the subsequent night (2300-0700), somnopolygraphic sleep recordings were obtained, and concentrations of cortisol, growth hormone (GH), and testosterone were measured every 15 min. During the no exercise nights, the typical secretory patterns were present with peak concentrations of GH but nadir concentrations of cortisol during the first half of sleep but increased cortisol levels and minimum GH levels during the second part of sleep. Testosterone concentrations increased during the second half of sleep. LDE of moderate intensity reduced rapid-eye-movement sleep [13.9 vs. 16.9% (no exercise); P < 0.01]. Levels of testosterone decreased with increasing intensity of daytime exercise (P < 0.05). Moderate-, but not low-intensity, LDE decreased GH levels in the first half (P < 0.05) and increased GH levels in the second half (P < 0.005) of sleep. Also, LDE of moderate intensity but not LDE of low intensity increased cortisol levels during the first half (P < 0.005) and decreased cortisol secretion during the second half (P < 0.05) of sleep. Results suggest that nocturnal profiles of GH and cortisol concentrations may serve to indicate the disturbance of normal anabolic functions of sleep due to daytime exercise.     

Relative effects of prolonged social isolation and confinement: Behavioral and EEG changes.

Studied the relative effects of social isolation and confinement, of 1-wk duration, on measures of EEG activity, intellectual test performance, affect, and a variety of psychological and somatic symptoms derived from Myers postisolation questionnaire. Ss were 66 male undergraduates. No significant differences in performance were observed on any of the 11 tests of the intellectual battery or on measures of subjective stress and mood. However, a significant decrease in occipital alpha frequency was obtained in both the socially isolated and confined groups after the 1-wk period. Since there was no significant difference between these 2 groups in the magnitude of the decrease, this EEG change appears to have resulted from confinement alone. An analysis of the questionnaire data revealed significant F ratios on 16 of the 22 content areas. 10 of the 16 symptom categories were associated with confinement alone and the remainder were associated either with social isolation or a combination of social isolation and confinement. Results of this study were compared with those reported in several earlier, 1-wk experiments on perceptual deprivation. (23 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hormonal dynamics during mate choice in the northern pintail: a test of the 'challenge' hypothesis

In previous mate choice experiments, we found no relationship between dominance rank and pairing success in male northern pintails, Anas acutaOnce chosen by a female, however, males became aggressive, initiated fights with higher-ranked males and quickly established dominance. In the present study, we tested a variation of the 'challenge' hypothesis, that the behavioural stimuli associated with acquiring and defending a mate induce an increase in testosterone level, which in turn facilitates aggressive behaviours required for males to establish dominance. We measured plasma hormone levels (testosterone, dihydrotestosterone, luteinizing hormone and corticosterone) before and after mate choice in two experiments in which males competed for a single female (experiments 1 and 2) and in a control experiment in which no female was introduced (experiment 3). We used groups of either three adult males (experiment 1) or one adult and two yearling males (experiments 2 and 3). Contrary to expectation, in experiment 1, plasma levels of corticosterone increased significantly and testosterone levels decreased in chosen males following mate choice. The magnitude of change in corticosterone was positively correlated with the rate of aggression by males. Chosen adult males in experiment 2 showed similar patterns of hormone change (corticosterone increase and testosterone decrease), although not all changes were significant. Hormone levels of unchosen yearlings in experiment 2 and control adults and yearlings in experiment 3 showed no changes. The results are consistent with the hypothesis that behavioural stimuli associated with successful pair formation induce a transitory increase in circulating levels of corticosterone, which in turn mediates the behavioural response of increased aggression leading to the establishment of dominance following mate choice. A short-term increase in corticosterone may be adaptive in this situation because it would mobilize energy stores needed by the male to defend the new pair bond and establish dominance.Copyright 1997 The Association for the Study of Animal Behaviour1997The Association for the Study of Animal Behaviour     

On the stress dependence of viscosity changes during structural relaxation of Fe40Ni40B20

According to Taub [Acta metall. 30, 2129 (1982)] the linearity between stress and strain rate during structural relaxation of amorphous alloys breaks down at low stresses. This statement is reexamined in this paper. It proves to be essential to take into account the length contraction due to the structural relaxation in determining the true strain rate. This contribution was determined experimentally for Fe₄₀Ni₄₀B₂₀. After applying the correction the viscosity becomes stress independent again. The contraction due to structural relaxation can be accurately calculated using the free volume model.     

Hormonal events during female puberty in relation to breast cancer risk

Cigarette smoking among adolescents continues to be a major public health problem in the United States. Smoking trends from 1976-1977 to 1992-1994 were examined in the Bogalusa Heart Study, an investigation of cardiovascular disease risk factors among black and white, male and female adolescents in a semirural town in the southern United States. Age-race-sex specific chi 2 tests for trends over five survey periods were conducted. In almost every age group, black boys and girls were less likely to be current smokers or to have ever smoked or tried cigarettes, as compared with white boys and girls, respectively (P < 0.01). Within age groups, few significant trends in smoking status from 1976-1977 through 1992-1994 were observed among white boys and girls. Among black males and females, however, sharp decreases were observed among all age groups in the prevalence of having ever smoked or tried cigarettes (P = 0.0001) and among the older age groups in the prevalence of being a current smoker (P = 0.0001). Thus, substantial declines in the prevalence of smoking were observed among black children but not among white children. Further research is required to understand why these ethnic differences in smoking occurred so that public health programs may target further the smoking behaviors in children.     

Hormonal regulation of heparin secretion by rat mast cells during stress

Administration of non-selective beta-blocker propranolol prevented the stress-activated action whereas the alpha-agonist isoprenaline enhanced the effect of immobilisation stress on the rat mast cells. beta-antagonists or agonists exerted no effect on the heparine secretion by the mast cells. ACTH activated the secretion in the absence of stress.     

Microstructural changes during creep of a high chromium steel

This article paper deals with creep deformation of a high-chromium steel, X-20. Creep tests were performed at three temperatures, 500 °, 550 °, and 600 °, under various loads. Some of the tests terminated in rupture, while others were interrupted and examined by optical micro-scopy and scanning electron microscopy (SEM). It was found that at the onset of tertiary creep, the creep rate begins to decrease for a certain period of time and a “step” appears on the creep curve. Study of the microstructure revealed that at the beginning of the step, the martensite needles start to rotate toward the tensile axis, and at the end of the step most of the needles are parallel to this direction. Hot-rolled pieces of the steel confirmed this observation; after rolling to a reduction of 35 pct, all the martensite needles lie parallel to the rolling direction and, therefore, the step was not observed. We offer an explanation for the step on the creep curve based on the rotation of the martensite.     

Structural changes in a railway wheel rim during operation

The structural changes in the near-surface layers of a railway wheel rim are studied during operation in rolling stock. The standard operating conditions of rail transport are shown to be characterized by alternating impact loading; regular braking; and, hence, periods of rapid heating of the surface layers in wheels that are replaced by intense heat removal after the end of braking of rolling stock. In this case, the heating of wheels is sufficient for the beginning of phase transformations, which result in softening, embrittlement, and strain aging of the near-surface layer metal.     

Punishment and the length of non-shock confinement during the extinction of avoidance.

Groups of 72 male Sprague-Dawley rats, trained to avoid in an alley with 3 distinct chambers, spent either 2, 15, or 30 sec. in the safe or goal chamber (GB) during extinction, with the remainder of the constant 150-sec intertrial interval (ITI) spent in the start box (SB). 1/2 the Ss of each group were punished (shocked) in the middle chamber during extinction, 1/2 were not. It was found that (1) the longer the goal confinement, the greater the resistance to extinction; regular extinction groups extinguished faster than the punished; and (3) there was no significant interaction between GB confinement and the punishment variable. During extinction in Exp. 2 there were 2 levels of goal confinement (2 vs. 30 sec.), equal time spent in SB in all groups, a constant ITI of 62 sec., and punishment vs. no punishment. 48 male Sprague-Dawley rats served as Ss. As anticipated, punishment prolonged extinction only for the 30-sec GB confinement; the other 3 groups extinguished at approximately the same rate. The concept of short-latency "relief" was invoked to explain this significant interaction. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hormonal changes and pituitary histological and immunocytochemical studies of patients with multiple organ failure

OBJECTIVE: We investigated the correlation between the endogenous hormonal changes of pituitary-adrenal and pituitary-thyroid hormones and the prognosis of patients in multiple organ failure, and elucidated the mechanism of blunted thyrotropin (TSH) secretion by histological and immunocytochemical studies of anterior pituitary glands. PATIENTS: Forty-three patients were studied who had been admitted to the intensive care unit of Sapporo Medical University Hospital and had been diagnosed as having multiple organ failure. MEASUREMENTS: Pituitary adrenal hormones [corticotropin (ACTH), cortisol] and pituitary thyroid hormones [TSH, triiodothyronin (T3), free-T3, thyroxine (T4), free-T4, thyroxine-binding globulin (TBG)] were measured, and TSH and prolactin (PRL) responses thyrotropin-releasing hormone (TRH) were examined within 24 hours of admission to the ICU. Individual variables were compared between survivors (n = 19) and nonsurvivors (n = 24). Thirteen patients (five survivors, eight nonsurvivors) were investigated again before discharge from the ICU or death. Morphology was examined by hematoxilin-eosin staining, and avidin-biotin-peroxidase complex immunostaining was used to demonstrate the spectrum of TSH in 14 nonsurvivors. RESULTS: (1) ACTH levels remained within the normal range, while cortisol levels increased to above normal levels. Neither hormone showed significant differences between survivors and nonsurvivors. In nonsurvivors, cortisol levels decreased before death despite the increased ACTH levels. (2) T3 and free-T3 levels decreased markedly to below normal values, and reverse-T3 levels increased markedly to above normal values. Nonsurvivors showed significant differences in TSH, T4 and reverse-T3 levels compared with survivors. (3) TSH response to TRH was blunted in both groups but PRL response to TRH was normal. Nonsurvivors showed severely depressed TSH response. Nonsurvivors continued to show blunted TSH response to TRH, while this improved in survivors. (4) The histological study did not show very serious damages to anterior pituitary glands as TSH secretion was depressed. Many TSH immunoreactive cells were also observed by immunocytochemical study. CONCLUSION: Decreased cortisol, low T4 levels and blunted TSH response to TRH correlated with mortality in MOF patients. Histological and immunocytological studies suggest that blunted TSH secretion is not caused by pituitary damages or TSH exhaustion but by disturbances in TSH secretion. This blunted TSH secretion is reversible and its improvement is an indicator of survival.     

Changes in EEG alpha frequency and evoked response latency during solitary confinement.

1 wk. of solitary confinement of 20 18-45 yr. old prison inmates produced significant changes in their EEG frequency and visual evoked potentials (VEP) that parallel those reported in laboratory studies of sensory deprivation. EEG frequency declined in a nonlinear manner over the 7-day period. VEP latency, which decreased with continued solitary confinement, was shorter for these Ss than for control Ss whose VEP latency did not change over the same period. Experimental Ss who had been in prison longer had shorter VEP latencies than relative newcomers to the prison. (20 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hormonal influences during the ontogeny of maternal behavior in female rats.

Two experiments involving a total of 223 female and 46 male CD rats examined the influence of ovarian hormones on sensitization latencies at different periods in ontogeny and on the olfactory inhibition of maternal behavior, maternal nest building, and pup retrievals from a T-maze extension of the home cage. Ss ovariectomized before puberty failed to show a decline in sensitization latencies when tested 3.5 wks postoperatively; Ss ovariectomized during and after puberty had significantly longer latencies than sham operates when tested 8 or more weeks later. Interrupting olfaction by intranasal ZnSO? reduced latencies. Ovariectomized Ss built less compact maternal nests, and fewer retrieved pups from a –T maze than did sham operates. Estradiol benzoate prior to pup exposure significantly reduced sensitization latencies of ovariectomized Ss, increased the proportion retrieving pups from the maze, and tended to increase maternal nest ratings. Findings indicate that ovarian hormones, primarily estrogen, exert a tonic facilitatory influence on maternal responsiveness, beginning at puberty. (31 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hormonal regulation during cardiac surgery operations on the "dry" heart

Central and peripheral compartments of hypophyseo-adrenal regulation, the state of renin-angiotensin-aldosterone system (RAAS) and thyroid-stimulating functions of hypophysis have been assessed in 72 patients with heart valve defects operated under profound hypothermal perfusion. It has been established that cardiopulmonary bypass surgery with profound hypothermia is accompanied by moderate and reversible changes in the above parameters. The activity of hypophyseo-adrenal system and RAAS reaches the maximum during a warming-up period and then gradually decreases. TSH content considerably decreases in the early postoperative period. Cardiopulmonary bypass surgery with profound hypothermia causes more pronounced changes in neurohormonal regulation than heart valve correction under hypothermal perfusion, which might be associated with blood flow arrest in major vessels causing changes in peripheral metabolic processes.     

Vagal paraganglioma: a review of 46 patients treated during a 20-year period

BACKGROUND: Vagal paragangliomas (VPs) arise from paraganglia associated with the vagus nerve. Approximately 200 cases have been reported in the medical literature. Because of their rarity, most information regarding these tumors has arisen from case reports and small clinical series. OBJECTIVE: To detail the clinicopathologic features of 46 patients with VP with an emphasis on the role of a multidisciplinary skull base team in both the successful extirpation and rehabilitation. DESIGN: Retrospective review of 46 patients with VP managed by a single skull base team. SETTING: An academic tertiary medical center. RESULTS: Forty-six patients were treated over a 20-year period (1978-1998). Ten (22%) demonstrated intracranial extension. There was a history of familial paragangliomas in 9 (20%) of the patients. The incidence of multicentric paragangliomas was 78% in patients with familial paragangliomas vs 23% in patients with nonfamilial paragangliomas. Management of this group of 46 patients consisted of surgery (n = 40), radiation therapy (n = 4), and observation (n = 2). The operative approach consisted of a transcervical excision often combined with a transtemporal or lateral skull base approach as dictated by the tumor extent. Postoperative cranial nerve deficits were common, and, as such, aggressive rehabilitation was a vital component in the management of these tumors. CONCLUSIONS: The management of VP and its associated cranial nerve deficits remains a difficult clinical problem. Options for treatment include surgical resection, radiation therapy, and, in selected cases, observation. Surgical extirpation requires a multidisciplinary skull base team to achieve complete tumor resection. Radiation therapy is reserved for elderly patients and patients at risk for bilateral cranial nerve deficits. Rehabilitation of cranial nerve deficits is an integral part of the management of VP.