Hormonal Regulation of Fluid and Electrolytes during Prolonged Bed Rest: Implications for Microgravity

1989 ◽  
pp. 215-232 ◽  
Author(s):  
John E. Greenleaf
Keyword(s):  
Hormonal Regulation ◽  
Bed Rest

Altered hormonal regulation and blood flow distribution with cardiovascular deconditioning after short-duration head down bed rest

2007 ◽  
Vol 103 (6) ◽  
pp. 2018-2025 ◽  
Author(s):  
D. Fischer ◽  
P. Arbeille ◽  
J. K. Shoemaker ◽  
D. D. O'Leary ◽  
R. L. Hughson
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Angiotensin Ii ◽  
Stroke Volume ◽  
Vascular Resistance ◽  
Hormonal Regulation ◽  
Venous Pressure ◽  
Plasma Concentrations ◽  
Bed Rest ◽  
Arterial Blood

This study tested the hypothesis that cardiovascular and hormonal responses to lower body negative pressure (LBNP) would be altered by 4-h head down bed rest (HDBR) in 11 healthy young men. In post-HDBR testing, three subjects failed to finish the protocol due to presyncopal symptoms, heart rate was increased during LBNP compared with pre-HDBR, mean arterial blood pressure was elevated at 0, −10, and −20 mmHg and reduced at −40 mmHg, central venous pressure (CVP) and cardiac stroke volume were reduced at all levels of LBNP. Plasma concentrations of renin, angiotensin II, and aldosterone were significantly lower after HDBR. Renin and angiotensin II increased in response to LBNP only post-HDBR. There was no effect of HDBR or LBNP on norepinephrine while epinephrine tended to increase at −40 mmHg post-HDBR ( P = 0.07). Total blood volume was not significantly reduced. Splanchnic blood flow taken from ultrasound measurement of the portal vein was higher at each level of LBNP post-compared with pre-HDBR. The gain of the cardiopulmonary baroreflex relating changes in total peripheral resistance to CVP was increased after HDBR, but splanchnic vascular resistance was actually reduced. These results are consistent with our hypothesis and suggest that cardiovascular instability following only 4-h HDBR might be related to altered hormonal and/or neural control of regional vascular resistance. Impaired ability to distribute blood away from the splanchnic region was associated with reduced stroke volume, elevated heart rate, and the inability to protect mean arterial pressure.

No effect of artificial gravity on lung function with exercise training during head-down bed rest

2015 ◽  
pp. 1-7
Author(s):  
Longxiang Su ◽  
Yinghua Guo ◽  
Yajuan Wang ◽  
Delong Wang ◽  
Changting Liu
Keyword(s):  
Lung Function ◽  
Pulse Rate ◽  
Vital Capacity ◽  
Pulmonary Ventilation ◽  
Bed Rest ◽  
Forced Expiratory Volume ◽  
Observation Time ◽  
Artificial Gravity ◽  
Postural Changes ◽  
Expiratory Flow

AbstractTo explore the effectiveness of microgravity simulated by head-down bed rest (HDBR) and artificial gravity (AG) with exercise on lung function. Twenty-four volunteers were randomly divided into control and exercise countermeasure (CM) groups for 96 h of 6° HDBR. Comparisons of pulse rate, pulse oxygen saturation (SpO2) and lung function were made between these two groups at 0, 24, 48, 72, 96 h. Compared with the sitting position, inspiratory capacity and respiratory reserve volume were significantly higher than before HDBR (0° position) (P< 0.05). Vital capacity, expiratory reserve volume, forced vital capacity, forced expiratory volume in 1 s, forced inspiratory vital capacity, forced inspiratory volume in 1 s, forced expiratory flow at 25, 50 and 75%, maximal mid-expiratory flow and peak expiratory flow were all significantly lower than those before HDBR (P< 0.05). Neither control nor CM groups showed significant differences in the pulse rate, SpO2, pulmonary volume and pulmonary ventilation function over the HDBR observation time. Postural changes can lead to variation in lung volume and ventilation function, but a HDBR model induced no changes in pulmonary function and therefore should not be used to study AG CMs.

GENE ACTIVATION IN MAMMARY CELLS

1972 ◽  
Vol 71 (2_Suppla) ◽  
pp. S346-S368 ◽  
Author(s):  
Roger W. Turkington ◽  
Nobuyuki Kadohama
Keyword(s):  
Cell Differentiation ◽  
Gene Transcription ◽  
Hormonal Regulation ◽  
Gene Activation ◽  
Milk Proteins ◽  
Mouse Mammary Gland ◽  
Nuclear Proteins ◽  
Mammary Cells ◽  
Alveolar Cells ◽  
Mammary Cell

ABSTRACT Hormonal activation of gene transcription has been studied in a model system, the mouse mammary gland in organ culture. Transcriptive activity is stimulated in mammary stem cells by insulin, and in mammary alveolar cells by prolactin and insulin. Studies on the template requirement for expression of the genes for milk proteins demonstrate that DNA methylation has an obligatory dependence upon DNA synthesis, but is otherwise independent from hormonal regulation of mammary cell differentiation. Incorporation of 5-bromo-2′deoxyuridine into DNA selectively inhibits expression of the genes for specific milk proteins. Undifferentiated mammary cells activate the synthesis of specific acidic nuclear proteins when stimulated by insulin. Several of these induced acidic nuclear proteins are undetectable in unstimulated undifferentiated cells, but appear to be characteristic components of the nuclei of differentiated cells. These results indicate that mammary cell differentiation is associated with a change in acidic nuclear proteins, and they provide evidence to support the concept that acidic nuclear proteins may be involved in the regulation of gene transcription and of mammary cell differentiation.

Modern approaches to the prevention and treatment of alterations in reproductive health in women with somatoform disorders and autonomic homeostasis

2016 ◽  
pp. 98-101
Author(s):  
Vl.V. Podolsky ◽  
◽  
V.V. Podolsky ◽  
Keyword(s):  
Reproductive Health ◽  
Hormonal Regulation ◽  
Preventive Measures ◽  
Somatoform Disorders ◽  
Emotional Health ◽  
Uterine Fibroids ◽  
Reproductive Function ◽  
Epidemiological Studies ◽  
Prevention And Treatment ◽  
Artificial Abortion

The objective: the developing of a system of preventive measures and principles of pregravid preparation for women with somatoform disorders and violation of autonomic homeostasis (VAH), in which observed changes in reproductive health (CRH) in the shape of states after undergoing artificial abortion, infertility and uterine fibroids. Patients and methods. Conducted clinical and epidemiological studies in the population of women of fertile age (WFA) allowed identifying for further examination of women with CRH in the form of state after undergoing artificial abortion, infertility and uterine fibroids in women with VAH. Further women were examined, in particular the conducted clinical and instrumental methods of research; determined the state of autonomic homeostasis and psycho emotional health of the biotopes of the organism, immunity; analyzed the hormonal regulation of the menstrual cycle; performed genetic studies and determined the morphofunctional state of reproductive system. Results. The most frequent complications during pregnancy in women who had CRH in history in the form of abortions, infertility and uterine fibroids and in the background of the PAF, there was a threat of interruption of pregnancy (often in I and II trimester – 56%) and preterm delivery (21%). The study of the catamnesis of further reproductive health found that in the case of well-conducted therapeutic measures in women undergoing artificial abortion, had infertility and uterine leiomyoma in the background of VAH, restore reproductive function, and in 82% of cases occurred a pregnancy. Conclusion. The the provided study of reproductive health, and state of various organs and systems of fertile aged women with somatoform disorders and violations of the autonomic homeostasis allowed to develop preventive measures for these women and pregravid preparation with the inclusion to the therapy Magnesium and vitamins (Magne-В6®). Key words: somatoform disorders, violation of autonomic homeostasis, changes in reproductive health, prevention and treatment, women of fertile age, Magne-В6®.

Delayed interval delivery of the second and third fetuses in multiple pregnancy triplet (Сase report)

2016 ◽  
pp. 148-152
Author(s):  
Y. Dubossarskaya ◽  
◽  
L. Padalko ◽  
L. Zakharchenko ◽  
E. Savel’eva ◽  
...  
Keyword(s):  
Preterm Delivery ◽  
Multiple Pregnancy ◽  
Bed Rest ◽  
Perinatal Morbidity ◽  
Perinatal Complications ◽  
Triplet Pregnancy ◽  
Satisfactory Condition ◽  
Nulliparous Women ◽  
Perinatal Center ◽  
Delayed Interval Delivery

This article describes a clinical case of vaginal delivery in nulliparous women 24 years old delayed interval delivery of the second and third fetuses in spontaneous multiple pregnancy dichorionic triamniotic triplet in a tertiary perinatal center. After preterm delivery in 27+5 weeks of gestation the first fetus to reduce perinatal morbidity and mortality of two fetuses that are left in the uterus, with informed consent of the woman preterm delivery the second and third fetuses occurred at intervals of 38 days, in 33+1 weeks of gestation. Careful monitoring of the state of the mother and fetuses was conducted. To increase the interval between the birth of the first fetus and the second and the third fetuses, prevention of obstetric and perinatal complications used tocolysis, antibiotics, progesterone, the prevention of respiratory distress syndrome of the newborn by corticosteroids and bed rest. Three girls were born alive with a weight of 980, 1800 and 1950 grams correspondingly. Childbirth complicated second degree perineal laceration and retained portions of placenta and membranes, puerperal period was uneventful. After 1.5 months, all infants discharged with her mother in a satisfactory condition with a weight of more than 3000 grams. Key words: multiple pregnancy, triplet pregnancy, delayed interval delivery in triplet pregnancy, preterm delivery.

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