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PubMed1994

Longitudinal analysis of adolescent growth in height, fatness, and fat patterning in rural South African black children.

Adolescent growth in height, fatness, and fat patterning was investigated in a sample of 79 rural South African black children studied longitudinally from 6-18 years. Data were analyzed relative to peak height velocity (PHV) to identify the phenomenon of "compensatory" growth in height during adolescence and to describe changes in fatness and fat patterning. Compensatory growth following PHV was clearly observed relative to NHANES data for African-Americans in that Z-scores for height at the start of the adolescent growth spurt were greater than those at the end of the spurt. Statistically significant differences in fatness and centralization between males and females did not occur until about 2 years after PHV was attained. Centralization of fat occurred in both sexes but more so in males. The lack of centralization in females was due to relatively greater triceps skinfold velocities. The rapid gain in post-PHV fatness in females may represent a physiological adaptation to an energetically sub-optimal environment, buffering the energetic costs of reproduction.

Adipose Tissue↗
PubMed1983

The hourly pattern of urine solute and electrolyte excretion following standard surgical trauma.

Although urine volume (and, less frequently, concentration) is often measured in the perioperative period, little attempt has been made to separate temporal phases of the intra- and postoperative response to surgery. In 7 patients undergoing standard severe single trauma and managed by a conventional regimen which included intraoperative Hartmann's solution, we have investigated the hourly pattern of urine solute and electrolyte excretion over the first 48 h. Contrary to expectation, in the first 5 h Na+ excretion increases in association with overall solute excretion, and thereafter progressively diminishes. K+ excretion increases 4 h postoperatively and remains elevated for 24 h, after which it returns to normal, even though Na+ excretion remains low. Free water excretion is negative for the first 24 h, though urine osmolality does not suggest a maximal antidiuretic response by the kidney--the highest concentration achieved being just below 800 mosmol/kg. In order to distinguish between the physiological adaptive changes due to starvation and those due to injury, the hourly pattern of urine solute and electrolyte excretion was further investigated in 12 healthy volunteers mimicking postoperative conditions. Apart from the early postoperative period, the hourly pattern of Na+, K+ and osmolar excretion shows no discernible difference from the operated group. These results show that, particularly in relation to Na+, the changes seen in the post-injury patient, even after major uncomplicated surgery, are largely adaptive, and this is especially striking at 24 h after surgery.

Esophagus↗
PubMed1985

Physiological nature of the internal mammary artery grafts.

A 4-month postoperative angiographic study of an internal mammary artery (IMA) graft illustrates its capacity to regulate flow by changes in caliber in response to changes in coronary vascular resistance. This physiological adaptability may be one of the reasons for excellent long-term results of in situ IMA grafts.

Coronary Circulation↗
PubMed2005

Employment pathways in a large cohort of adult cancer survivors.

BACKGROUND: Employment and work-related disability were investigated in a cohort of adult cancer survivors who were working when they were diagnosed from 1997 to 1999 with a variety of cancers. Employment from the time of diagnosis through the early years of survivorship was studied, self-reported effects of cancer survival on disability and employment were quantified, and risk factors associated with cancer-related disability and withdrawal from employment were identified. METHODS: One thousand four hundred thirty-three cancer survivors were interviewed by telephone from 1 year to nearly 5 years after diagnosis. They were asked retrospectively about employment from the time of diagnosis to follow-up and about work-related disability at follow-up. They also were asked whether disabilities or reasons for quitting work were cancer-related. Return to work and quitting work were projected over time in a life-table analysis. Risk factors were identified from logit analyses. RESULTS: One of five survivors reported cancer-related disabilities at follow-up. Half of those with disabilities were working. A projected 13% of all survivors had quit working for cancer-related reasons within 4 years of diagnosis. More than half of survivors quit working after the first year, when three-quarters of those who stopped for treatment returned to work. Survivors of central nervous system, head and neck, and Stage IV blood and lymph malignancies had the highest adjusted risk of disability or quitting work. CONCLUSIONS: Cancer survival sometimes has long-term effects on employment and the ability to work. Employment outcomes can be improved with innovations in treatment and with clinical and supportive services aimed at better management of symptoms, rehabilitation, and accommodation of disabilities.

Adaptation, Physiological↗
PubMed2004

Distribution of transcription factor inducible cyclicAMP early repressor (ICER) in rodent brain and pituitary.

In morphogenetic dynamics of neurons, and in adaptive physiology of brain function, transcription factors of the cyclicAMP signaling pathway, such as activator cyclicAMP responsive element binding protein (CREB) and inhibitor inducible cyclicAMP early repressor (ICER), play an important role. In particular, the presence of the transcription factor ICER in neurons or neuroendocrine cells suggests the need for the gating of an up-regulated gene expression. Little is known, however, about the natural distribution of the inhibitory transcription factor ICER. We, therefore, mapped the rodent brain and pituitary for an ICER immunoreaction and found a nuclear staining for this transcription factor. ICER-positive glial cells were found throughout the brain. ICER-positive neurons were found in sensory input centers, like the olfactory bulb, or sensory brain stem nuclei, and in hypothalamic nuclei involved in central neuroendocrine control. In addition, neuroendocrine/endocrine transducers, like the pituitary and the pineal gland showed a high basal presence of ICER. Our data show that a basic ICER level is required by many cell systems and can be seen as an anticipatory and/or a protective measure in systems with superior reactive dynamics.

Animals↗
PubMed1989

Auditory pathway and auditory activation of primary visual targets in the blind mole rat (Spalax ehrenbergi): I. 2-deoxyglucose study of subcortical centers.

The blind mole rat Spalax ehrenbergi is a subterranean rodent that shows striking behavioral, structural, and physiological adaptations to fossorial life including highly degenerated eyes and optic nerves and a behavioral audiogram that indicates high specialization for low-frequency hearing. A 2-deoxyglucose functional mapping of acoustically activated structures, in conjunction with Nissl/Klüver-Barrera-stained material, revealed a typical mammalian auditory pathway with some indications for specialized low-frequency hearing such as a poorly differentiated lateral nucleus and a well-developed medial nucleus in the superior olive complex. The most striking finding was a marked 2-deoxyglucose labeling of the dorsal lateral geniculate body and of cortical regions that correspond to visual areas in sighted rodents. The results render the blind mole rat a good model system for studying natural neural plasticity and intermodal compensation. In this report, we confine ourselves to the subcortical levels. The cortical level will be dealt comprehensively in a following paper.

Acoustic Stimulation↗
PubMed2006

Parity does not alter baseline or stimulated activity of the hypothalamus-pituitary-adrenal axis in women.

Pregnancy is associated with considerable physiological adaptations, some of which long outlast the state of pregnancy. Although it is well documented that pregnancy produces alterations of the hypothalamus-pituitary-adrenal axis, the longer-term effects of pregnancy on this system have not been systematically examined in humans. Subjects in the present study were 159 nulliparous and 265 parous women. Data analysis revealed no impact of parity on baseline activity (salivary cortisol: response to awakening, F </= .03, day profile: F </= 3.89, both n.s.). In a subsample, similar results were obtained for dexamethasone-suppressed salivary cortisol levels (all F </= 1.45 n.s., n = 45), as well as salivary cortisol, total cortisol, and ACTH responses to stimulation with a psychosocial stress protocol (all F </= .93 n.s., n = 47). These findings suggest that parity is not associated with long-term alterations of hypothalamus-pituitary-adrenal axis activity, and postpregnancy measures can, therefore, be used as proxy markers for a woman's prepregnancy status of this system.

Adrenocorticotropic Hormone↗
PubMed2004

Quality of life in elderly patients with head and neck cancer one year after diagnosis.

BACKGROUND: Little is known about quality of life (QOL) in elderly patients. METHODS: Seventy-eight older (> or =70 years) and 105 younger patients (45-60 years) with carcinoma of the oral cavity, pharynx (stage > or =II), or larynx (stage > or =III) completed the European Organization for Research and Treatment of Cancer (EORTC) Core Quality of Life Questionnaire and EORTC Head and Neck Cancer Quality of Life Questionnaire before treatment. Fifty-one older and 70 younger patients completed all follow-up questionnaires at 3, 6, and 12 months. RESULTS: Before and after treatment, the physical functioning of the older patients was worse than that of younger patients. This difference remained relatively constant during follow-up and is probably related to normal aging. At baseline and 3 months, no other differences were found between both groups. At 6 months, younger patients reported more pain, but at 12 months no relevant differences were found. CONCLUSIONS: Treatment did not affect QOL differently in older and younger patients. Therefore, standard treatment should always be considered, irrespective of the patient's age.

Adaptation, Physiological↗
PubMed2004

Bilirubin inhibits iNOS expression and NO production in response to endotoxin in rats.

The inducible isoform of heme oxygenase (HO), HO-1, has been shown to play an important role in attenuating tissue injury. Because HO-1 catalyzes the rate-limiting step in bilirubin synthesis, we examined the hypothesis that bilirubin is a key mediator of HO-1 cytoprotection, employing a rat model of endotoxemia. Bilirubin treatment resulted in improved survival and attenuated liver injury in response to lipopolysaccharide infusion. Serum levels of NO and tumor necrosis factor alpha, key mediators of endotoxemia, and hepatic inducible nitric oxide synthase (iNOS) expression were significantly lower in bilirubin-treated rodents versus control animals. Both intraperitoneal and local administration of bilirubin also was found to ameliorate hindpaw inflammation induced by the injection of lambda-carrageenan. Consistent with in vivo results, bilirubin significantly inhibited iNOS expression and suppressed NO production in lipopolysaccharide (LPS)-stimulated RAW 264.7 murine macrophages. In contrast, bilirubin treatment induced a threefold increase in LPS-mediated prostaglandin synthesis in the absence of significant changes in cyclooxygenase expression or activity, suggesting that bilirubin enhances substrate availability for eicosanoid synthesis. Bilirubin had no effect on LPS-mediated activation of nuclear factor kappaB or p38 mitogen-activated protein kinase, consistent with a nuclear factor kappaB-independent mechanism of action. Taken together, these data support a cytoprotective role for bilirubin that is mediated, at least in part, through the inhibition of iNOS expression and, potentially, through stimulation of local prostaglandin E2 production. In conclusion, our findings suggest a role for bilirubin in mollifying tissue injury in response to inflammatory stimuli and support the possibility that the phenomenon of "jaundice of sepsis" represents an adaptive physiological response to endotoxemia. Supplementary material for this article can be found on the HEPATOLOGY website (http://interscience.wiley.com/jpages/0270-9139/suppmat/index.html).

Animals↗
PubMed1995

Optimization of hemodynamic energy expenditure in the arterial system.

Experimental evaluations and comparisons of the passive and active biomechanical properties of isolated blood vessels from different species (dog, pig, calf, human), as well as the nature of different arterial pressure oscillations, reveal that: 1) Characteristic impedance of middle-size and large arteries changes with intraluminal mean pressure usually resulting in a U-shaped function with a minimum value around the normal physiological 100 mmHg pressure; 2) Similarly, pressure dependent adrenergic diameter responses (active strain) of different large arteries also exhibit parabolic shape with an extreme (maximum) value at 50-100 mmHg intraluminal pressure, suggesting that biomechanical characteristics of the vessel wall may define an optimum for hemodynamic operations; 3) Changes in the arterial smooth muscle tone shift the characteristic impedance curve along the pressure axis and alter the slopes of the parabola; 4) There are significant interactions between the fast 1st-order (pulsatile) and the slow 3rd-order arterial pressure wave components. These and some other characteristics of the circulatory system suggest the existence of an "extremal" forced oscillation blood pressure control mechanism in the body, optimizing the afterload of heart and the blood perfusion of systemic microvessels by minimizing the pulsatile energy expenditure at the physiological mean pressure operation level. A versatile mathematical model of this hypothetical mechanism was developed by us on an IBM PC using Pascal and 8086 Assembly languages. Simulation experiments show that such a physiological adaptive system could control arterial pressure effectively. The computer model is available on a PC disc.

Animals↗
PubMed1994

Preflight adaptation training for spatial orientation and space motion sickness.

Two part-task preflight adaptation trainers (PATs) are being developed at the NASA Johnson Space Center to preadapt astronauts to novel sensory stimulus conditions similar to those present in microgravity to facilitate adaptation to microgravity and readaptation to Earth. This activity is a major component of a general effort to develop countermeasures aimed at minimizing sensory and sensorimotor disturbances and Space Motion Sickness (SMS) associated with adaptation to microgravity and readaptation to Earth. Design principles for the development of the two trainers are discussed, along with a detailed description of both devices. In addition, a summary of four ground-based investigations using one of the trainers to determine the extent to which various novel sensory stimulus conditions produce changes in compensatory eye movement responses, postural equilibrium, motion sickness symptoms, and electrogastric responses are presented. Finally, a brief description of the general concept of dual-adapted states that underly the development of the PATs, and ongoing and future operational and basic research activities is presented.

Adaptation, Physiological↗
PubMed1994

Space sickness and fluid shifts: a hypothesis.

In a sample of 64 first-time Space Shuttle crew members, 9 preflight variables related to fluid, electrolyte, and cardiovascular status were previously found to be significantly related to space sickness. The nine variables are serum uric acid, red cell count, environmental temperature at the launch site, serum phosphate, urine osmolality, serum thyroxine, sitting systolic blood pressure, calculated blood volume, and serum chloride. Using discriminant analysis, these preflight variables were used to correctly classify the 64 astronauts according to their space sickness incidence (NOTSICK or SICK) with 80% success, using two methods of pseudo-crossvalidation. Symptoms of motion sickness may be induced on Earth, either with a sufficiently high level of vestibular stimulation or with less vestibular stimulation after reducing the threshold for motion sickness induction. Some of the nine predictor variables support a fluid shift hypothesis of space sickness etiology by which central volume expansion in weightlessness may lower the threshold required for novel vestibular stimulation to cause space sickness. According to this hypothesis, some astronauts suffer a greater central volume expansion than do others, causing them to have greater physiologic responses to fluid shifts, which, in turn, proportionally reduces their threshold for induction of space sickness. The hypothesis is supported by preflight and postflight echocardiographic comparisons of heart volumes in 19 shuttle astronauts. The postflight left ventricular diastolic volume index was decreased by 34 +/- 3% in the astronauts with MODERATE or SEVERE space sickness, but only 9 +/- 5% (P < .05) in the NONE or MILD group, indicating that an exaggerated physiologic adaptation to fluid shifts is associated with space sickness.

Atrial Function↗
PubMedDate not supplied

Roy's adaptation model: a guide for rehabilitation nursing practice.

Roy's Adaptation Model provides a framework for holistic rehabilitation nursing practice. In this article, the model is applied to a rehabilitation patient with a spinal cord injury for the assessment of behaviors and stimuli influencing the behaviors and also for planning and evaluating nursing care.

Adaptation, Physiological↗
PubMed2001

Adrenergic regulation of cardiac myocyte apoptosis.

The direct effects of catecholamines on cardiac myocytes may contribute to both normal physiologic adaptation and pathologic remodeling, and may be associated with cellular hypertrophy, apoptosis, and alterations in contractile function. Norepinephrine (NE) signals via alpha- and beta-adrenergic receptors (AR) that are coupled to G-proteins. Pharmacologic studies of cardiac myocytes in vitro demonstrate that stimulation of beta1-AR induces apoptosis which is cAMP-dependent and involves the voltage-dependent calcium influx channel. In contrast, stimulation of beta2-AR exerts an anti-apoptotic effect which appears to be mediated by a pertussis toxin-sensitive G protein. Stimulation of alpha1-AR causes myocyte hypertrophy and may exert an anti-apoptotic action. In transgenic mice, myocardial overexpression of either beta1-AR or G(alpha)s is associated with myocyte apoptosis and the development of dilated cardiomyopathy. Myocardial overexpression of beta2-AR at low levels results in improved cardiac function, whereas expression at high levels leads to dilated cardiomyopathy. Overexpression of wildtype alpha1B-AR does not result in apoptosis, whereas overexpression of G(alpha)q results in myocyte hypertrophy and/or apoptosis depending on the level of expression. Differential activation of the members of the mitogen-activated protein kinase (MAPK) superfamily and production of reactive oxygen species appear to play a key role in mediating the actions of adrenergic pathways on myocyte apoptosis and hypertrophy. This review summarizes current knowledge about the molecular and cellular mechanisms involved in the regulation of cardiac myocyte apoptosis via stimulation of adrenergic receptors and their coupled effector pathways.

Adrenergic alpha-Agonists↗
PubMed1992

Establishment of a Chinese hamster ovary cell line that expresses grp78 antisense transcripts and suppresses A23187 induction of both GRP78 and GRP94.

GRP78, a 78,000 dalton protein residing in the endoplasmic reticulum, is postulated to play important roles in protein folding and cell survival during calcium and other physiological stress. Here we describe the construction of an eukaryotic expression vector for the constitutive expression of grp78 antisense RNA and the creation of a CHO cell line, 78WO, which expresses high levels of the grp78 antisense RNA through amplification of the stably transfected antisense vector. We observed that whereas 78WO maintains a basal level of GRP78 similar to that of control cells, GRP78 is no longer inducible by A23187. The 78WO cells have undergone a compensatory increase in grp78 transcription such that the effects of antisense are cancelled out at the protein level under nonstressed conditions. In these same cells, GRP94, a 94,00 dalton ER protein, is also rendered noninducible by A23187. This provides the first evidence that the regulation of two ER proteins might be coupled such that the failure to induce GRP78 results in the down-regulation of GRP94. The 78WO cell line grows with a doubling time of about 26 hr and exhibits decreased tolerance to A23187, suggesting the GRPs contribute to cell viability under calcium stress. The establishment of this cell line, which can be stably maintained, will provide a useful tool for testing whether the induction of the GRPs is important for protein folding or transport and whether their enhanced synthesis is the cause or consequence of a variety of physiological adaptations.

Animals↗
PubMed2005

Effects of prolonged acclimation to intermediate photoperiod and photo-schedule reversal in photosensitive golden hamsters.

We investigated the effect of prolonged acclimation to 12 hr of light and photo-schedule reversal during the time of photosensitivity in golden hamsters (Mesocricetus auratus). Before the experiments, animals were housed under natural photoperiod and then transferred to 12L:12D (light 12 hr:dark 12 hr) in autumn for 12 weeks. After 4 weeks of acclimation, photo-schedule was reversed (12D:12L). First experiments were done after 4 weeks of acclimation to an ambient temperature (T(a)) of 23 degrees C and a 12L:12D photo-schedule. We examined the daily variations in brown adipose tissue (BAT) capacity for nonshivering thermogenesis (NST). Noradrenaline (NA) injections were given every 4 hr while BAT temperature (T(BAT)) and preferred ambient temperature (PT(a)) were monitored continuously and simultaneously in a thermal gradient system. Then, we investigated the effect of light-dark cycle reversal on a daily rhythm of NST. The hamsters were acclimated to the photo-schedule reversed by 12 hr and the same T(a). After 4 and 8 weeks of acclimation to a reversed photo-schedule, the experiments were repeated. We found that the daily rhythm of the response to NA was entrained to the new light-dark cycle after 4 weeks of acclimation to a reversed photo-schedule. Maximum effect of NA was always recorded during the light phase and in the latter part of the dark phase of the day. NA-induced increase in T(BAT) was correlated with the decrease in PT(a), and was also inversely correlated with pre-injection T(BAT). These data imply that the daily rhythm of the capacity for NST opposes the daily rhythm of body temperature (T(b)). After 8 weeks of acclimation to the reversed photo-schedule, the rhythmicity of the response to NA disappeared, and the daily fluctuations in T(BAT) were the smallest. This lack of rhythm may be a physiological adaptation to winter conditions when the daily amplitude of T(b) rhythm is markedly reduced and, as a consequence, NST capacity does not vary within the day. Moreover, after 8 weeks of acclimation to reversed photo-schedule, NST capacity decreased while response to saline increased. During the experiments, hamsters were photosensitive and were changing to their winter status. However, because of the lack of cold during acclimation, the capacity for NST did not increase. Increased responsiveness to saline, indicating an increase in stress-induced thermogenesis, might be advantageous for "fight or flight" reaction.

Acclimatization↗
PubMed1982

The relation between the status of adaptive system and the number of postoperative complications in patients with gastrointestinal cancer: the effect of phenazepam.

The decrease in 11-hydroxycorticosteroids concentration caused by 0.5 mg of dexamethasone administered at 11 pm was studied in 91 primary patients suffering from gastrointestinal cancer. In dexamethasone-resistant patients postoperative complications developed in 65% of colon cancer patients and in 42% of stomach cancer patients. In dexamethasone-sensitive patients the complications were observed in 24% and 12% of patients, correspondingly. The elevation of hypothalamic threshold of sensitivity to the inhibiting effect of glucocorticoids, revealed by the dexamethasone suppression test, was considered to be as result of a combined action of age, the tumor itself, and pronounced emotional stress during the preparation for operation. The derivative of benzodiazepin--phenazepam--when administered before the operation in colon cancer patients improved the results of the dexamethasone suppression test and decreased the number of postoperative complications.

11-Hydroxycorticosteroids↗