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PubMed1975

Adaptation and failure of adaptation to extreme natural environments.

Although the environmental stresses to which man is subjected on the ground are less than those commonly encountered in aviation or under water, they may still exceed an individual's powers of adaptation. Extremes of temperature, commonly encountered in the Arctic or the tropics, may occur in regions of normally temperate climate and lead to failure of temperature regulation, resulting in hypothermia, frostbite, heat exhaustion, or heat stroke. High mountains impose additional hazards due to high winds and lack of oxygen, and deep mines are dangerous work-places because of high temperature and humidity. Some physiological acclimatization occurs in extreme natural environments and the dangers may be reduced by appropriate clothing, diet and behaviour.

Adaptation, Physiological↗
PubMed2003

Platelet-mediated modulation of adaptive immunity. A communication link between innate and adaptive immune compartments.

Platelets are highly reactive components of the circulatory system with well-documented hemostatic function. Recent studies extend platelet function to modulation of local inflammatory events through the release of chemokines, cytokines, and a number of immunomodulatory ligands, including CD154. We hypothesized that platelet-derived CD154 modulates adaptive immunity. The data reported herein demonstrate that platelets, via CD154, induce dendritic cell maturation, B cell isotype switching, and augment CD8(+) T cell responses both in vitro and in vivo. Platelet transfusion studies demonstrate that platelet-derived CD154 alone is sufficient to induce isotype switching and augment T lymphocyte function during viral infection, leading to enhanced protection against viral rechallenge. Additionally, depletion of platelets in normal mice results in decreased antigen-specific antibody production.

Adaptation, Physiological↗
PubMed2004

Adaptive behavior in autism and Pervasive Developmental Disorder-Not Otherwise Specified: microanalysis of scores on the Vineland Adaptive Behavior Scales.

The purpose of this study is to provide a microanalysis of differences in adaptive functioning seen between well-matched groups of school-aged children with autism and those diagnosed as having Pervasive Developmental Disorder-Not Otherwise Specified, all of whom functioned in the mild to moderate range of intellectual impairment. Findings indicate that the major area of difference between children with autism and those with Pervasive Developmental Disorder-Not Otherwise Specified, was expressive communication; specifically, the use of elaborations in syntax and morphology and in pragmatic use of language to convey and to seek information in discourse. Linear discriminant function analysis revealed that scores on just three of these expressive communication item sets correctly identified subjects in the two diagnostic categories with 80% overall accuracy. Implications of these findings for both diagnosis and intervention with children with Autism Spectrum Disorders will be discussed.

Activities of Daily Living↗
PubMed1975

Effects of ingestion of organic selenium in adapted and non-adapted rats.

1. Rats were given moderate-selenium (4-5 mg/kg) or low-Se (0-5 mg/kg) diets during gestation and lactation. Their young were given diets with high (10 mg/kg), moderate or low Se contents from weaning, and groups of rats were killed at intervals during the 14-week experimental peroid. 2. Compared with young rats which received the low-Se diet, those which received the moderate- or high-Se diets had a high incidence of liver lesions and there were changes in liver Se content, haemoglobin concentration, packed cell volume, prothrombin activity, fibrinogen content, spleen weight, body water and serum glutamic-oxaloacetic and glutamic-pyruvic transaminas (L-aspartate : 2-oxoglutarate aminotransferase; EC 2.6.1.1 and L-alanine : 2-oxoglutarate aminotransferase; EC 2.6.1.2 respectively) and alkaline phosphatase (EC 3.1.3.1) activities. In those rats which received the high-Se diet the changes were more pronounced than in those which received the moderate-Se diet. 3. In young rats from dams given moderate-Se diets, which were themselves given the moderate-Se diet, the liver Se content decreased continuously, whereas rats given the same diet but from dams which had received the low-Se diet, the liver Se content increased continuously. There was a slight improvement of symptoms of Se toxicity in all groups by the 5th week of the experimental peroid. 4. The results suggest that there was an adaptation to chronic Se intake.

Adaptation, Physiological↗
PubMed1999

Adaptive and non-adaptive responses in rats exposed to ozone, alone and in mixtures, with acidic aerosols.

Healthy young adult (300 g) Sprague-Dawley rats were exposed for 1-day or 5-day periods, nose only, to purified air (CA) or four different pollutant atmospheres. Pollutant atmospheres included (a) 0.2 ppm ozone; (b) 0.4 ppm O3; (c) a low concentration mixture of ozone and sulfuric acid-coated carbon particles (0.2 ppm, 100 microg/m(3) and 50 microg/m(3), respectively); and (d) a high-concentration O3 and sulfuric acid-coated carbon particle mixture (0.4 ppm, 500 microg/m(3) and 250 microg/m(3), respectively). Following 1-day exposures to the high O3 concentration, significant (p< or =.05) decreases were observed in respiratory tidal volumes and significant increases were observed in lung inflammatory response. Following 5-day exposures to 0.4 ppm ozone, tidal volumes and lung inflammation were not significantly different from those seen in CA controls. In contrast, following 5-day exposures to the high-concentration O3-particle mixture, lung inflammation was increased significantly relative to that seen after 1-day high concentration mixture exposure or after CA exposure. Macrophage Fc-receptor binding, an important immunological function of macrophages, was significantly depressed after 5-day exposures to either the high- or low-concentration O3-particle mixtures compared to 1-day exposures or to CA. Thus, at the concentrations tested, repeated exposures to O3 produced diminished responses in breathing pattern changes and lung parenchymal injuries compared to acute, single exposures. This diminution was not observed after exposures to mixtures of acidic particles plus ozone. We conclude that mixtures of ozone and acidic particles may alter adaptive mechanisms that have been reported by us and others after repeated exposures to ozone alone.

Adaptation, Physiological↗
PubMed2005

The interplay of cutaneous water loss, gas exchange and blood flow in the toad, Bufo woodhousei: adaptations in a terrestrially adapted amphibian.

Toads experiencing dehydrating conditions exhibit complex physiological and behavioral responses, some of which can potentially impact cutaneous gas exchange, an important component of total gas exchange. We measured the effect of dehydration on cutaneous gas exchange in the xeric-adapted toad Bufo woodhousei. First, two pharmacological agents were used to stimulate cutaneous blood flow--phentolamine (an alpha-blocker) and isoproterenol, a beta-stimulant and powerful cardio-accelerator--to determine a relationship between cutaneous blood flow and water loss. Both drugs increased heart rate and blood pressure, and caused visually evident extensive vasodilation of the skin. Untreated toads in a dry air stream took an average of 10.1+/-0.7 h to dehydrate to 80% body mass, while animals treated with isoproterenol and phentolamine requires only 7.2+/-0.8 h and 7.4+/-0.9 h, respectively. Rehydration, which was more rapid than dehydration, was similarly accelerated in pharmacologically treated toads. Cutaneous gas exchange (M(O2), M(CO2)) and C18O diffusing capacity (D(Skin)C18O) were then examined in unanesthetized toads under different states of body hydration. Blood gases and hematocrit were measured separately but under identical conditions. In fully hydrated toads at 23-25 degrees C, cutaneous gas exchange values were: M(O2) = 1.43+/-0.47 micromol g(-1) h(-1), M(CO2) = 1.75+/-0.85 micromol g(-1) h(-1), and the respiratory exchange ratio R = 1.36+/-0.56 (N=6, mean + 1 S.D.). D(Skin)C18O was 0.48+/-0.03 micromol g body mass(-1) h(-1) kPa. Following an enforced 20-25% loss of body water, D(Skin)C18O fell by nearly 50% to 0.28+/-0.09 micromol g(-1) h(-1) kPa. However, cutaneous M(O2), M(CO2) and R were unchanged at 1.48+/-0.15 micromol g(-1) h(-1), 1.72+/-0.29 micromol g(-1) h(-1) and 1.13+/-0.08 micromol g(-1) h(-1), respectively. Partial pressure of arterial (sciatic) oxygen, Pa(O2), normally about 12-13 kPa, remained unchanged by dehydration, but Pa(CO2) increased about 250% from 0.93+/-0.27 up to 2.27+/-0.93 kPa. The fall in D(Skin)C18O during dehydration presumably results at least in part from decreased cutaneous blood flow, possibly in an attempt to reduce the transcutaneous water loss that would otherwise result during dehydrating conditions. Concurrently, cutaneous M(CO2) is maintained under dehyrdating conditions by a greatly increased Pa(CO2) diffusion gradient across the skin. Thus, Bufo woodhousei appears able to restrict cutaneous blood flow without compromising vital cutaneous CO2 loss.

Adaptation, Physiological↗
PubMedDate not supplied

Surgery in the prism adaptation study: accuracy and dose response. Prism Adaptation Study Research Group.

Three hundred twenty-two patients underwent strabismus surgery for acquired esotropia according to a rigid protocol in the Prism Adaptation Study (PAS). This report describes the PAS surgical technique and the methods used to evaluate and assure adherence to the surgical protocol. We present analyses of the discrepancies between the amount of recession surgery planned by the surgeon and the amount of recession estimated by the masked graders from documentary photographs. In 74% of patients, the total discrepancy (combined from both medial rectus operations) was 1 mm or less. There was a distinct trend for masked graders to estimate larger recession amounts than were dictated by the protocol and claimed to be done by the surgeon. In 24% of patients, the masked graders estimated that the recession was more than 1 mm greater than that claimed by the surgeon, while in 2%, the graders estimated that the surgery was more than 1 mm less than planned. Of the 74 patients for whom the graders' estimated total recession was more than 1 mm greater than the amount planned by the surgeon, 88% were successful. Of the six patients for whom the graders' estimated total recession was more than 1 mm less than the amount planned by the surgeon, five (83%) were successful. We propose new surgical tables for patients with acquired esotropia. Enhanced amounts of recession appear to be necessary to decrease the rate of undercorrection for each group of patients.

Adaptation, Ocular↗
PubMed1975

The role of the parathyroids for the adaptation to a low calcium intake. 4. The long-term effect of parathyroidectomy on the adaptation to a low calcium intake in adult rats with special reference to calcium metabolism.

One-year-old selectively parathyroidectomized rats showed, on a normal dietary intake of calcium, phosphorus and vitamin D, a reduction in plasma calcium to below 4.1 mEq./1 in 86 per cent and on restricted calcium intake in 100 per cent. On the normal level of dietary calcium, normalization of plasma calcium occurred 17 per cent within 8 weeks and in another 40 per cent between the 8th and 27th week of observation while on the low level only 10 per cent of the animals normalized their plasma calcium and first after the long-term period of observation. This was most probably accomplished by successively restored parathyroid activity from aberrant parathyroid tissue as deducted from data regarding the metabolism of calcium, magnesium and inorganic phosphate. Adaptation, viz. normalization of plasma calcium, was brought about by mobilization of skeletal calcium with resulting osteoporosis, as reported in our previous study on the same animals. Intestinal net absorption of calcium showed no significant difference between normocalcemic normophosphatemic intact and hypocalcemic hyperphosphatemic parathyroidectomized animals at the respective level of dietary calcium. Thus, parathyroidectomized animals with persistently reduced plasma calcium showed a normal adaptory increase in intestinal calcium absorption upon chronically restricted calcium intake. In the discussion of the regulation of this adaptory system the possible effects of the plasma concentrations of both calcium and inorganic phosphate upon the intracellular Ca22+concentration in the kidney tubules must be considered. Plasma magnesium did not appear to have a primary influence. Intestinal absorption of inorganic phosphate was not dependent upon the presence of the parathyroids but followed that of calcium suggesting a regulation by the action of 1,25-dihydroxycholecalciferol.

Adaptation, Physiological↗
PubMedDate not supplied

Is ADHD adaptive or non-adaptive behavior?

The evolutionary approach to the issue of ADHD derives from the assumption that what is regarded as a pathological phenomenon today was once an adaptive response to the conditions of life in the ancestral stages of human development. The paper argues against this conception on the basis of the clinical picture of ADHD. The author believes that in the previous "natural" conditions the ADHD syndrome was even more of a maladaptation than in the "protective" conditions of present-day life.

Adaptation, Psychological↗
PubMed1978

Effects of cold adaptation and re-adaptation upon the mitochondrial phospholipids of brown adipose tissue.

1. A study of the mitochondrial phospholipids, phospholipid fatty acid patterns and enzyme activities was investigated in brown tissue (B.A.T.) from rats chronically exposed to cold and/or treated with thyroxine. 2. The total activities of the oxidative enzymes were increased after cold exposure, but not after thyroxine treatment. 3. Cold exposure increased the amount of phosphatidylethanolamine, phosphatidylcholine, cardiolipin and lysophospholipids, the effect being greatest for phosphatidylethanolamine. At the same time, there were marked alterations in the fatty acid composition of the mitochondrial phospholipids (decrease of palmitic, palmitoleic and oleic acids ; increase of stearic, linoleic and arachidonic acids). 4. All these cold-induced alterations were reversed by re-adaptation of the animal to a normal temperature range. 5. The alterations of the fatty acid composition of phospholipids could be explained by changes in the rate of individual fatty acid biosynthesis.

Adaptation, Physiological↗
PubMed1994

["Adaptive transposition" of retrotransposons in the Drosophila melanogaster genome accompanying the increase in features of adaptability].

Two cases of spontaneous transpositions of MDG1, MDG3, and copia retrotransposons were detected in Drosophila melanogaster lines derived from the nonadaptive NA line and marked by recessive visible mutations. The transpositions were accompanied by a dramatic increase in individual fitness (competitive success). In independent instances of MDG1 transpositions, the location patterns of new sites were similar. These results confirm the existence of adaptive transpositions that were demonstrated earlier for the NA line that carried no visible markers.

Adaptation, Physiological↗
PubMed1993

[Adaptive and non-adaptive reactions of central hemodynamics to conditions of heat discomfort].

Chest rheography was used to study central hemodynamics in 134 healthy males aged 18-28 in comfortable weather conditions and discomfortable ones, that is at equivalent-effective temperature 17-24 degrees C and above 27-30 degrees C, respectively. In trained subjects from native and non-native population under comfortable weather conditions heart rate (HR) proved to be significantly reduced as compared to untrained subjects (57.6 +/- 1.1 and 56.2 +/- 1.2 against 73.9 +/- 1.7 and 70.4 +/- 0.9), whereas stroke volume in trained males was significantly larger (by 14.2 and 14.0%, respectively). Minute blood volume (MBV), cardiac and stroke indices, systolic and diastolic pressure showed no significant differences. Heat discomfort gave rise to a slow-pulse trend in trained subjects from both native and non-native populations, in untrained subjects, especially non-natives heart rate accelerated. MBV increased in trained native and non-native examinees by 11.0 and 11.1%, respectively, while in untrained natives the rise reached 17.2%. This was secured by stroke volume elevation by 14.3, 10.7 and 11.2%, respectively (p < 0.05), in non-natives by acceleration of heart rate by 11.2%. A trend to lowering of arterial pressure was more marked in untrained examinees of both populations. It is evident that in conditions of arid zone heat discomfort trained subjects from both native and non-native populations exhibited adequate hemodynamic responses, whereas strain was observed in circulatory system functioning when it adapted to heat discomfort in untrained non-natives.

Acclimatization↗
PubMed1981

Mutants of adenovirus type 12 after adaptation to growth in tumor cell lines. II. Reproducible acquisition of additional sequences after adaptation to a human cervical cancer line.

Adaptation of adenovirus type 12 to growth in a human cervical cancer line (C4/1) results in the reproducible selection of viral mutants carrying additional DNA sequences at the right-hand end of the genome which range in size from 190 to 400 base pairs. The viral mutants have selective growth advantage in comparison to the non-affected wild type, even after subsequent passages in human KB cells, commonly used for adenovirus propagation. Detailed restriction endonuclease analysis of one of the mutant DNAs shows that the additional sequences are located within the terminal 195 base pairs of the right end of the genome.

Adenoviruses, Human↗
PubMed1990

Evaluation in children of cold-adapted influenza B live attenuated intranasal vaccine prepared by reassortment between wild-type B/Ann Arbor/1/86 and cold-adapted B/Leningrad/14/55 viruses.

A reassortant cold-adapted (ca) influenza B experimental live attenuated intranasal vaccine was evaluated for safety and immunogenicity in children by means of a blind, placebo controlled study. The vaccine contained the haemagglutinin and neuraminidase genes, and the gene for its non-structural proteins from wild-type (wt) B/Ann Arbor/1/86 virus, the contemporary strain at the time of the study. Other genes were derived from ca B/Leningrad/14/55 virus. No increase in illness rates was seen in the children from ages 3-15 years given vaccine at maximum potency (a one in two dilution of infectious allantoic fluid, having a titre of 10(7.0) EID50) compared to children given placebo. About 60% of seronegative children, ages 3-7 years, exhibited a detectible antibody response following one dose of intranasal vaccine, with the seroresponse rate rising to greater than 70% after two doses of vaccine. Immunogenicity was lowest in seropositive children age 8-15 years, reaching a maximum of 36% after two doses. Results indicated that the vaccine was highly attenuated, and probably of adequate immunogenicity for kindergarten age children. The lower immunogenicity in older children suggests the vaccine might be overly attenuated for use in school-age children who are more likely to have a history of prior natural infection with influenza B virus. Further clinical and epidemiological studies of protection are needed to fully assess this.

Administration, Intranasal↗