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PubMed1991

Organ transplantation and pregnancy. A case report and review.

The 1980s has been described as the "decade of transplantation" and organ transplantation as a "paradigm of medical progress." The considerable improvements in immunosuppression that have been made in the last few years have led to an increased repertoire of organ-to-organ combination transplants, more procedures, and markedly increased survival time for both grafts and recipients. Inevitably, there will be an increased number of women recipients who later undergo pregnancy. Although there is a wide experience with pregnancy after renal transplantation, there are as yet relatively few reports of pregnancy after other major organ transplants. A case is presented of a 22-year-old primiparous woman who elected to conceive and complete a pregnancy 2 years after cardiac transplantation because of cardiomyopathy. The pregnancy was complicated by a rejection episode early in the third trimester but eventually resulted in forceps delivery of a live male infant at 41 weeks' gestation. The pregnancy and organ transplantation literature is reviewed with special attention, illustrated by the case report, to the physiologic adaptation to pregnancy of the transplanted organ, the potential teratogenic effects of the immunosuppressive drugs used in pregnancy, and the contrasts between renal and other major organ transplants.

Adaptation, Physiological↗

PubMed1995

Patency of an internal thoracic artery graft despite maximal competitive flow.

Recent evidence has suggested that competitive flow is an important factor in early graft failure. In this case report an internal thoracic artery graft was used to revascularize an acute coronary artery dissection after balloon angioplasty. Subsequent angiography 4 months later showed complete healing of the dissection, yet the internal thoracic artery graft remained widely patent in spite of the maximal competitive flow from the native coronary artery. This concurs with experimental results recently reported in The Annals regarding the physiologic adaptability of the internal thoracic artery graft to suit flow requirements and its versatility as the conduit of choice.

Adaptation, Physiological↗

PubMed1990

Medical considerations for extending human presence in space.

The prospects for extending the length of time that humans can safely remain in space depend partly on resolution of a number of medical issues. Physiologic effects of weightlessness that may affect health during flight include loss of body fluid, functional alterations in the cardiovascular system, loss of red blood cells and bone mineral, compromised immune system function, and neurosensory disturbances. Some of the physiologic adaptations to weightlessness contribute to difficulties with readaptation to Earth's gravity. These include cardiovascular deconditioning and loss of body fluids and electrolytes; red blood cell mass; muscle mass, strength, and endurance; and bone mineral. Potentially harmful factors in space flight that are not related to weightlessness include radiation, altered circadian rhythms and rest/work cycles, and the closed, isolated environment of the spacecraft. There is no evidence that space flight has long-term effects on humans, except that bone mass lost during flight may not be replaced, and radiation damage is cumulative. However, the number of people who have spent several months or longer in space is still small. Only carefully-planned experiments in space preceded by thorough ground-based studies can provide the information needed to increase the amount of time humans can safely spend in space.

Adaptation, Physiological↗

PubMed1991

Physiological alterations during pregnancy: impact on toxicokinetics.

The physiological changes that occur in the alimentary, cardiovascular, pulmonary, and renal organ systems during pregnancy are designed to increase availability of nutrients to and remove wastes from the fetus. Although this is a general requirement, not all animals use the same strategies to meet these goals. These physiological adaptations will impact on toxicokinetics and may alter toxicodynamics. Absorption, distribution, metabolism, transfer between maternal and fetal compartments, and elimination will change for many xenobiotics during pregnancy. The changes in body weight, total body water, plasma proteins, body fat, and cardiac output will alter the distribution of many xenobiotics (Hytten and Leitch, 1971; Hytten and Chamberlain, 1980; Mattison, 1986). As the toxicokinetic parameters change across species, it is important to understand their impact on chemicals associated with maternal, placental, and fetal toxicity for appropriate cross-species extrapolation.

Adaptation, Physiological↗

PubMed1984

Investigations on-board the biosatellite Cosmos-83.

The program of the 5 day flight of the biosatellite Cosmos-1514 (December 1983) envisaged experimental investigations the purpose of which was to ascertain the effect of short-term microgravity on the physiology, growth and development of various animal and plant species. The study of Rhesus-monkeys has shown in that they are an adequate model for exploring the mechanisms of physiological adaptation to weightlessness of the vestibular apparatus and the cardiovascular system. The rat experiment has demonstrated that mammalian embryos, at least during the last term of pregnancy, can develop in microgravity. This finding has been confirmed by fish studies. The experiment on germinating seeds and adult plants has given evidence that microgravity produces no effect on the metabolism of seedlings and on the flowering stage.

Adaptation, Physiological↗

PubMed1995

Metabolic rates and thermal conductance in four species of neotropical bats roosting in hot caves.

Data are presented on metabolic rates and thermal conductance for four species of neotropical bats, Pteronotus quadridens, Mormoops blainvillii (Mormoopidae), Monophyllus redmani and Erophylla bombifrons (Phyllostomidae). Each of these bats predominantly or exclusively roosts in hot caves (28-40 degrees C) in Puerto Rico. Basal metabolic rates (BMR) for these four species were 55%, 48%, 66%, and 66% of values expected from the Kleiber curve, respectively. Thermal conductance was 93%, 55%, 175%, and 158% of values expected from the Aschoff curve, respectively. These data indicate that, in addition to food habits, variation in BMR is highly correlated to roost microclimate. Pteronotus and Mormoops, like other insectivorous species, have low BMRs. The low BMR of the nectar/fruit eating Monophyllus and Erophylla, as well as the low termal conductance in Mormoops, is consistent with their habit of roosting in hot caves, suggesting that roost microclimate is an important selective force in the physiological adaptation of these bats.

Adaptation, Physiological↗

PubMed1979

Influence of the ambient acceleration field upon acute acceleration tolerance in chickens.

It has been demonstrated both in the Russian and in the American space programs that there is a progressive deconditioning of the circulatory system with exposure to weightlessness. Astronauts and cosmonauts returned to Earth have a significantly reduced orthostatic tolerance which will persist for a few days. We have measured the acceleration tolerance of domestic fowl, acutely exposed to a 6 g+z field, as the time over which a normal heart rate can be maintained. This period of circulatory accommodation ends abruptly with a marked bradycardia, which with continued treatment is terminal. For animals which have been previously chronically accelerated (e.g., physiologically adapted to a 2.5 g field) the acute acceleration tolerance is greatly increased. It appears that the influence of the ambient acceleration field in conditioning the responsiveness of the circulatory system is a general phenomenon.

Acceleration↗

PubMed2004

Differences in ingestive balance of two populations of neotropical Thrichomys apereoides (Rodentia, Echimyidae).

Thrichomys apereoides is widely distributed in the Caatinga, a semi-arid region in Brazil, but is presumed to lack capabilities for water conservation. In the present study, we compared two populations of adult individuals living under different precipitation conditions (700 and 450 mm year(-1)). Animals from the less dry area were twice as heavy as those from the drier locality. Under ad libitum water regimen, there were differences between populations in relative food intake as well as in water intake and urine concentration, but not in normalized body mass water intake. Under short-term water deprivation, both populations presented similar body mass loss. Whereas individuals from the more arid locality maintained food consumption, urine volume and urine osmolality, Thrichomys from the less dry locality reduced food consumption and urine volume. The occurrence of anuria in 75% of animals from this population indicates that the limits of their ability to deal with water shortage had been reached. The morphological and physiological difference and the non-allometric similarities found between the two populations of T. apereoides fulfill the criteria for physiological adaptations to differences in annual rainfall. Our data challenge the hypothesis that the irregularity of annual rainfall in the Caatinga precludes the evolution of adaptations to this semi-arid climate.

Adaptation, Physiological↗

PubMed2004

Kinematic parameters of the walking of herons, ground-feeders, and waterfowl.

The kinematic gait characteristics of six species of birds in three groups were compared. The groups studied were herons (Gray Herons and Little Egrets), ground-feeders (Domestic Pigeons and Gray Starlings), and waterfowl (Pintails and Black-headed Gulls). The results showed that the relative stride frequency was greater in the waterfowl than in the other species. Complementary to this, the amplitude of the movements was smaller in the waterfowl than in the others. These differences between the waterfowl and the other species might be caused by their morphological and/or physiological adaptation to swimming. Another possible cause for these differences was the magnitude of head bobbing, as the ground-feeders and herons, which walk with head bobbing, showed a large relative stride length and excursion angle, while the waterfowl, which do not head-bob, walk with a relatively short stride length and small excursion angle. Moreover, the relative magnitude of head movement during walking was especially large in Little Egrets, which showed an especially large relative stride length and excursion angle. These parameters may have some mechanical relationships with each other.

Adaptation, Physiological↗

PubMed2006

Amphibian renal disease.

Amphibians by nature have an intimate connection with the aquatic environment at some stage of development and fight an osmotic battle due to the influx of water. Many amphibians have acquired a more terrestrial existence at later stages of development and consequently have physiologic adaptations to conserve moisture. Renal adaptations have allowed amphibians successfully to bridge the gap between aqueous and terrestrial habitats. The kidneys, skin,and, in many amphibian species, the urinary bladder play key roles in fluid homeostasis. Renal impairment may be responsible for the clinical manifestation of disease, morbidity, and mortality.

Adaptation, Physiological↗

PubMed2005

Echocardiography to measure fitness of elite runners.

We evaluated the echocardiograms of 134 male and 54 female elite runners who competed over different distances to observe cardiac enlargement and differences among athletes engaged in different types of training, and to relate the echographic dimension with running performance. In male runners, left ventricular (LV) internal diameter at end diastole (LVIDd), LV mass, and left atrial diameter were increased by the length of distance ( P < .001) whereas right ventricular diameter was increased only in marathon runners. In female runners, this association was found when LVIDd, LV mass, and left atrial diameter were adjusted for body surface area ( P < .001). Wall thickness was not related to distance running. Abnormal LV dilation was associated with a low LV ejection fraction for the higher values of LVIDd, but not for the higher indexed LVIDd values. In male runners, LVIDd was associated with 100 m ( r = -0.67, P < .01), 10,000 m ( r = -0.70, P < .001), and marathon ( r = -0.54, P < .001) and in female runners with a 400-m ( r = -0.84, P < .001) race time. These results show that sprint- and endurance-trained runners had an eccentric hypertrophy and that it is necessary to establish a new upper limit of abnormal cavity dilatation as indexed LVIDd. The normal systolic function and the relationship between LVIDd and performance indicate that LV enlargement in elite runners is a physiologic adaptation and that echocardiographic assessment can be used to determine the fitness of runners.

Adaptation, Physiological↗

PubMed2005

Survival, Pb-uptake and behaviour of three species of earthworm in Pb treated soils determined using an OECD-style toxicity test and a soil avoidance test.

Mature (clitellate) Eisenia andrei Bouché (ultra epigeic), Lumbricus rubellus Hoffmeister (epigeic), and Aporrectodea caliginosa (Savigny) (endogeic) earthworms were placed in soils treated with Pb(NO(3))(2) to have concentrations in the range 1,000 to 10,000 mg Pb kg(-1). After 28 days LC50(-95%confidence limit)(+95%confidence limit) values were E. andrei 5824(-361)(+898) mg Pb kg(-1), L. rubellus 2867(-193)(+145) mg Pb kg(-1) and A. caliginosa2747(-304)(+239) mg Pb kg(-1) and EC50s for weight change were E. andrei2841(-68)(+150) mg Pb kg(-1), L. rubellus1303(-201)(+240) mg Pb kg(-1) and A. caliginosa1208(-206)(+212) mg Pb kg(-1). At any given soil Pb concentration, Pb tissue concentrations after 28 days were the same for all three earthworm species. In a soil avoidance test there was no difference between the behaviour of the different species. The lower sensitivity to Pb exhibited by E. andrei is most likely due to physiological adaptations associated with the modes of life of the earthworms, and could have serious implications for the use of this earthworm as the species of choice in standard toxicological testing.

Adaptation, Physiological↗

PubMed2006

The management of respiratory infections during pregnancy.

Respiratory infections that complicate pregnancy are encountered frequently, and they encompass a broad range of disorders. Although respiratory infections usually are not seen more commonly in pregnancy, they often result in greater morbidity and mortality secondary to the physiologic adaptations that occur during pregnancy. Pregnant patients who have one of these disorders require higher level of surveillance and intervention.

Adaptation, Physiological↗

PubMed2005

Prevalence and clinical significance of left atrial remodeling in competitive athletes.

OBJECTIVES: In the present study we assessed the distribution and clinical significance of left atrial (LA) size in the context of athlete's heart and the differential diagnosis from structural heart disease, as well as the proclivity to supraventricular arrhythmias. BACKGROUND: The prevalence, clinical significance, and long-term arrhythmic consequences of LA enlargement in competitive athletes are unresolved. METHODS: We assessed LA dimension and the prevalence of supraventricular tachyarrhythmias in 1,777 competitive athletes (71% of whom were males), free of structural cardiovascular disease, that were participating in 38 different sports. RESULTS: The LA dimension was 23 to 50 mm (mean, 37 +/- 4 mm) in men and 20 to 46 mm (mean, 32 +/- 4 mm) in women and was enlarged (i.e., transverse dimension > or = 40 mm) in 347 athletes (20%), including 38 (2%) with marked dilation (> or = 45 mm). Of the 1,777 athletes, only 14 (0.8%) had documented, symptomatic episodes of either paroxysmal atrial fibrillation (n = 5; 0.3%) or supraventricular tachycardia (n = 9; 0.5%), which together occurred in a similar proportion in athletes with (0.9%) or without (0.8%; p = NS) LA enlargement. Multivariate regression analysis showed LA enlargement in athletes was largely explained by left ventricular cavity enlargement (R2 = 0.53) and participation in dynamic sports (such as cycling, rowing/canoeing) but minimally by body size. CONCLUSIONS: In a large population of highly trained athletes, enlarged LA dimension > or = 40 mm was relatively common (20%), with the upper limits of 45 mm in women and 50 mm in men distinguishing physiologic cardiac remodeling ("athlete's heart") from pathologic cardiac conditions. Atrial fibrillation and other supraventricular tachyarrhythmias proved to be uncommon (prevalence < 1%) and similar to that in the general population, despite the frequency of LA enlargement. Left atrial remodeling in competitive athletes may be regarded as a physiologic adaptation to exercise conditioning, largely without adverse clinical consequences.

Adaptation, Physiological↗

PubMed2006

Effect of post-exercise sauna bathing on the endurance performance of competitive male runners.

The physiological adaptations to sauna bathing could enhance endurance performance. We have therefore performed a cross-over study in which six male distance runners completed 3 wk of post-training sauna bathing and 3 wk of control training, with a 3 wk washout. During the sauna period, subjects sat in a humid sauna at 89.9+/-2.0 degrees C (mean+/-standard deviation) immediately post-exercise for 31+/-5 min on 12.7+/-2.1 occasions. The performance test was a approximately 15 min treadmill run to exhaustion at the runner's current best speed over 5 km. The test was performed on the 1st and 2nd day following completion of the sauna and control periods, and the times were averaged. Plasma, red-cell and total blood volume were measured via Evans blue dye dilution immediately prior to the first run to exhaustion for each period. Relative to control, sauna bathing increased run time to exhaustion by 32% (90% confidence limits 21-43%), which is equivalent to an enhancement of approximately 1.9% (1.3-2.4%) in an endurance time trial. Plasma and red-cell volumes increased by 7.1% (5.6-8.7%) and 3.5% (-0.8% to 8.1%) respectively, after sauna relative to control. Change in performance had high correlations with change in plasma volume (0.96, 0.76-0.99) and total blood volume (0.94, 0.66-0.99), but the correlation with change in red cell volume was unclear (0.48, -0.40 to 0.90). We conclude that 3 wk of post-exercise sauna bathing produced a worthwhile enhancement of endurance running performance, probably by increasing blood volume.

Adaptation, Physiological↗

PubMed1987

Physical fitness for the mature woman.

The ability to perform physical activity, whether at work or as recreation, is an important aspect of human experience for men and women of all ages. The extension of the range of physical power output that characterizes improvement in "physical fitness" is a desirable goal for all. It helps to make physical activity more enjoyable and less fatiguing, it can facilitate the learning of new skills and may actually improve cognitive functions, and it decreases the likelihood of physical injury and helps to speed recovery from injury. A sound mind in a sound body has been a medical ideal since Greek and Roman times. For a continuing state of good health, all systems--physical, mental, and spiritual--should be exercised in harmony. At the beginning of the twentieth century, the average life span for women was barely 5 years beyond the menopause. Menopause heralded the twilight years of life and enhanced susceptibility to disease and deterioration of health. Today, women look forward to 25 additional years, a full one third of a lifetime; menopause now heralds potential promise, adventure, and exploration, an exciting new phase of the life cycle. Exercise represents a vital part of a prescription to maximize quality of life throughout this period. Physical conditioning cannot be expected to complete reverse the unrelenting effects of passing time, but it appears that it can substantially modify this process. Functional losses that in the past have been attributed only to age may, in fact, represent a combined effect of biologic aging and physical inactivity. Exercise helps to maintain the physiologic adaptations that support an enhanced biologic reserve in body systems that tend to lose reserve capacity with advancing age. "If you don't use it, you lose it!," and its positive corollary, "If you use it, you enthuse it!," may be maxims that imply a natural law of deep consequence. An optimal diet and suitably vigorous activity are advisable for all women as they enter the postmenopausal phase of life. Every mature woman ought to carefully consider choosing to pursue an appropriate goal: active participation in a specific exercise program under medical supervision. The health care system should be fully responsive to the special needs of the mature woman, and the importance of providing programs of physical activity designed to address these needs should be recognized. For the postmenopausal woman, the advantages of achieving a state of physical fitness are many.(ABSTRACT TRUNCATED AT 400 WORDS)

Adaptation, Physiological↗

PubMed2001

Pollution-induced community tolerance (PICT) and seasonal variations in the sensitivity of phytoplankton to atrazine in nanocosms.

Algae communities exposed to a herbicide like atrazine (PS II inhibitor) are expected to be selected and to be more tolerant to the herbicide than unexposed communities (pollution-induced community tolerance, PICT). The PICT may be an ecotoxicological tool for detecting this selective action of chronic pollution, and this method has been applied to several toxicants in experimental systems and in field studies. But the detection of PICT with PS II inhibitors has sometimes been variable. This work was done to study the long-term effects of exposure to atrazine (10 microg/l) and the PICT responses of phytoplankton communities in repeated outdoor nanocosms. Phytoplankton communities were sampled in Lake Geneva at different periods of the year and the effects of atrazine were analysed by studying community structure, biomass and primary production, and by measuring tolerance to atrazine in a short-term physiological test based on 14C incorporation. We find that PICT is a sensitive method for measuring effects. Even atrazine concentrations causing little restructuring induced tolerance in most of our experiments. But the short- and long-term responses of phytoplankton to atrazine varied between experiments, probably due to the initial compositions of the communities and environmental factors associated with seasonal parameters. The selection and detection steps of PICT to atrazine thus vary greatly with environmental conditions and the physiological adaptations of algae to the herbicide. To monitor risk assessment in aquatic systems, PICT studies applied to algae, must be investigated in the light of seasonal contaminations and seasonal events and successions.

Adaptation, Physiological↗

PubMed2002

The relationship between metal concentrations and phenotypes in the Baltic clam Macoma balthica (L.) from the Gulf of Gdansk, southern Baltic.

Soft tissue accumulated concentrations of nine metals (V, As, Se, Ag, Cd, Pb, Mn, Cu and Zn) were studied in two main phenotypes (1) according to external shell colour (white and pink), and (2) according to shell shape (shell with a rounded posterior end--"regular" and with an elongate posterior end and a notable flexure--"irregular") of the Baltic clam Macoma balthica from southern Baltic Sea off Poland. No differences in metal concentrations were observed between colour-based phenotypes. By contrast, "irregular" clams exhibited generally higher concentrations of all elements in their tissues than "regular" bivalves. This finding provides the first reference on a potential linkage of shell deformation with tissue metal concentrations within one entire population of clams living in the same habitat. Different ability of metal handling in the shape-based phenotypes is presumably related to different physiological capacity of the bivalves induced by the selection effect of specific environmental conditions. It is suggested that unfavourable conditions in deep waters of the Gulf of Gdansk (e.g. hypoxia/anoxia, hydrogen sulphide, elevated bioavailability of metals) induces, in a certain part of the population, morphological deformation of shell (thereby leading to irregular shape) and in parallel physiological adaptations which result in greater sensitivity to trace metals of "irregular" clams. This hypothesis however, requires further investigation with special focus on genetic divergences between phenotypes because till now we cannot exclude the co-occurrence of two types (semi-species) of clams in the Gulf: an Atlantic type and a Baltic type. Genetic analysis with a use of DALP technique revealed strong intrapopulational polymorphism but no fingerprints or intraspecific polymorphism characterising any of the phenotypes considered (both colour- and shape-based). Since eight polymorphic loci were clearly identified further studies of population genetic structure hold optimistic promise.

Adaptation, Physiological↗