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The natural killer (NK) reactivity of mouse spleen cells is controlled by the left brain neocortex and not by the right symmetrical brain area. The finding strongly suggests direct relationships between the central nervous system and the immune system, both involved in biological adaptation for the maintenance of homeostasis and body integrity in relation to the external environment.
In a group of 20 long-term psychogeriatric patients with uncontrolled diabetes, data on body weight, blood pressure and blood sugar concentration (fasting and postprandial) were correlated with the electroencephalographic (EEG) findings. The patterns were similar for the study subjects and for healthy subjects of the same age. The psychogeriatric patients with diabetes in contrast to psychogeriatric patients with chronic hypoglycemia, showed an increase in body weight and blood pressure and increase in blood sugar concentration with ageing; they also showed a normal EEG whereas chronically hypoglycemic patients usually had an abnormal EEG. In terms of blood glucose levels and excess glucose in the urine despite treatment, the diabetes had to be considered uncontrolled. However, these patients were clinically asymptomatic. Apparently, in these particular circumstances, the diabetes may be an adaptive biologic phenomenon.
Interference with the water-air interface, both direct (by contact with a flat, rigid surface) and indirect (by inducing a meniscus) caused the ciliated protozoa we investigated to actively collect in the water column or on the substrate directly under the area of altered surface tension. A crowding effect is observed in this "rest area" reaching plateau values within one hour after onset of the experiment. The simple experimental procedures described here induced analogous behaviour in both Paramecium caudatum (a swimmer) and Oxytricha bifaria (a crawler). The ciliates seem in this reaction to be seeking a refuge from vibrations transmitted by the free interface. Our discovery is discussed in its implications for the adaptive biology and ecology of these micro-organisms.
Three protistan genomes were analyzed for differential genetic traits that may be associated with biological adaptations to their unique life styles. The microsporidian, Encephalitozoon cuniculi, an obligate intracellular parasite; the ascomycetes, Pneumocystis carinii, considered an opportunistic pathogen; and Saccharomyces cerevisiae, a model organism exhibiting a free-living life style, were used in comparisons of genomic architecture, reproductive strategies, and metabolic capacity predicted by the presence of signature genes. Genome size, gene number, and metabolic function decreased as the organisms became more dependent on their hosts. In contrast, gene density and the percentage of genes dedicated to cell growth and division were substantially increased in the genome of E. cuniculi. The obligate life style was associated with reductions in gene number, genome size, and reduced metabolic capacity while the free-living life style was coincident with gene duplications and duplication of large portions of the genome. The genomic characteristics and metabolic capacity of P. carinii were usually intermediate between those of the other two protistan genomes, but unique characteristics such as the presence of a single rDNA locus may indicate that these organisms could be in the process of becoming more host dependent.
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There are two groups of microorganisms that live and grow in hypersaline (>10-15% NaCl) environments: the halophilic Archaea and the halotolerant Bacteria and algae. In order to grow and reproduce in such high-salt, low-water activity environments, these organisms have made basic biochemical adaptations in their proteins, osmoregulation mechanisms, nucleic acids, and lipids. The environment of the halophiles and especially how the halophilic Archaea have adapted to that environment are reviewed in this paper. Along with this review is a brief description of how these adaptations could be important in the detection of life on early Mars assuming similar types of salts and a carbon-based life.
Scheiner's principle has been used in electroretinographic optometry to refract the photoreceptor plane in different regions of the visual field of the pigeon eye. Along the horizon and in the upper visual field the eye is emmetropic, or nearly so. Below the horizon the eye becomes progressively more myopic at more negative elevations, refractive state falling to -5D at -90 deg. Lower field myopia is not an artifact of oblique astigmatism, nor of an aberration symmetrical about the optical axis. It is suggested that lower field myopia is a biological adaptation suited to keep the photoreceptors in the upper retina conjugate with the ground. Refractive state below the horizon can be fitted with a sine function by varying a parameter H (eye-ground height). The value of H agrees well with directly measured eye-ground height.
Many organisms construct structural ceramic (biomineral) composites from seemingly mundane materials; cell-mediated processes control both the nucleation and growth of mineral and the development of composite microarchitecture. Living systems fabricate biocomposites by: (i) confining biomineralization within specific subunit compartments; (ii) producing a specific mineral with defined crystal size and orientation; and (iii) packaging many incremental units together in a moving front process to form fully densified, macroscopic structures. By adapting biological principles, materials scientists are attempting to produce novel materials. To date, neither the elegance of the biomineral assembly mechanisms nor the intricate composite microarchitectures have been duplicated by nonbiological processing. However, substantial progress has been made in the understanding of how biomineralization occurs, and the first steps are now being taken to exploit the basic principles involved.
Biological adaptive systems share some common features: variation among their constituent elements and continuity of core information. Some of them, such as the immune system, are endowed with memory of past events. In this study we provide direct evidence that evolving viral quasispecies possess a molecular memory in the form of minority components that populate their mutant spectra. The experiments have involved foot-and-mouth disease virus populations with known evolutionary histories. The composition and behavior of the viral population in response to a selective constraint were influenced by past evolutionary history in a way that could not be predicted from examination of consensus nucleotide sequences of the viral populations. The molecular memory of the viral quasispecies influenced both the nature and the intensity of the response of the virus to a selective constraint.
The lung function of 23 underground coal workers and eight surface workers at a Scottish colliery was measured immediately before and after a work shift. Changes in lung function were assessed in relation to the measured respirable dust exposure and the time of day in which the shift was worked. Large, and statistically significant, decrements of lung function during the shift were found in night-shift workers compared with workers on other shifts. Measurements derived from the forced expiratory manoeuvre, particularly FEV1, Vmax50, and Vmax25, after three vital capacity breaths of an 80% He/20% O2 mixture, showed large reductions in night-shift men, smaller reductions in afternoon-shift men, and small increases or decreases in morning-shift underground and surface workers. Within-shift changes for other tests, such as closing volume, N2 index, and volume of isoflow, did not differ significantly between shifts. No significant relationship was found between dust exposure and functional changes during a shift for any test. Lung function changes in a control group of 25 female workers not exposed to dust (hospital nurses) did not show the same large variations between day and night shifts. Examination of a further control group of 16 office workers did not show any difference in diurnal changes between smokers and non-smokers. It is concluded that these coal miners, even on permanent shift patterns, had widely different changes in their lung function cycle depending on which shift they were working. These changes did not appear to be related to dust exposure or cigarette smoking and were not consistent with other biological adaptations known to result from regular night-shift working.
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Meditation, a wakeful hypometabolic state of parasympathetic dominance, is compared with other hypometabolic conditions, such as sleep, hypnosis, and the torpor of hibernation. We conclude that there are many analogies between the physiology of long-term meditators and hibernators across the phylogenetic scale. These analogies further reinforce the idea that plasticity of consciousness remains a key factor in successful biological adaptation.
BACKGROUND: The penetration of different wavelengths of UV radiation through human skin is of major importance, especially for the determination of photoprotective properties of sunscreens and UV-protective clothes. OBJECTIVE: In this study we present a new method for the measurement of UV transmission through small skin specimens. METHODS: The transmission measurements were performed by using a UV spectrophotometer with an integrating sphere operating in the wavelength range of 280-390 nm. For the skin samples, special quartz glass cuvettes were developed which allowed measurements for very thin and small skin specimens. Furthermore, the cuvettes prevented dehydration of the specimens and guaranteed, by using an additional diaphragm, that the transmission data were derived solely from the small skin specimen examined. Specimens measuring 8 x 3 mm(2) with a thickness of 0.3 mm (histometric and sonographic control) were taken from the thighs of 10 subjects via shave biopsy. RESULTS: In the UVA range (315-390 nm) we obtained a mean transmission of 4.6% and for the UVB range (280-315 nm) of 0.9%. No significant (p >0.14) difference of UV transmission was found between the individual skin specimens. CONCLUSION: This new method seems to be well suitable for UV transmission measurements of small skin specimens. As UVA radiation has a much deeper penetration depth and in in vivo situations dermal hemoglobin could have an effect on UV penetration, the present method is better suitable for the investigation of UVB-induced biological adaptation mechanisms and the impact of topical agents on UVB transmission of the epidermis.
With the technical progress made in fetal and neonatal intensive care, perinatal mortality has decreased by 25% over the last decade and has expanded the surviving premature population. Prematurity drastically changes the environment of the developing organism. Striking evidence from a number of disciplines has focused attention on the interplay between the developing organism and the circumstances in which it finds itself. The environmental event during a sensitive period in development, induces injury and/or biological adaptations that lead to altered differentiation of tissues. The organism can express specific adaptive responses to its environment which include short-term changes in physiology as well as long-term adjustments. This review addresses these short-term as well as longer-term changes occurring in lung and brain tissue and illustrates how these changes can be studied using advanced imaging techniques such as magnetic resonance imaging
Within any biological population there is considerable variation in the physical characteristics of individual members, and the understanding and classification of such populations always depends on the interpretation of this variation. A major point of this paper is that groups of neurones can also be regarded as biological populations, and that at least three distinct types of variation can be found within any neural population:role-indicating variation, which enables different cells or groups of cells to perform different functions; systematic variation, which allows different cells (or sometimes the same cell) to perform a particular function under varying conditions; and residual variation, which is principally related to mechanisms of evolution and provides the population with its biological adaptability. Examples of these three types of variation are suggested for a number of properties of retinal ganglion cell populations. A second major point is that any functional classification of nerve cells should contain multiple taxonomic levels, corresponding to different levels of complexity and interaction within the nervous system. Thus, individual cells can belong to more than one group, each at a different taxonomic level, and these groups of cells can be viewed as interacting with each other rather than as operating in isolation. A multiple-level classification of cat retinal ganglion cells is presented with two broad groups, each subdivided into two lower-level groups, and an attempt is made to identify the categories of visual function to which these groups are related.
This report explores the hypothesis that massive cholesteryl ester (CE) accumulation in macrophages, such as that occurring in atheroma foam cells, results in changes in the expression or modification of specific cellular proteins. Two-dimensional (2-D) gel electrophoretic patterns of metabolically labeled cellular proteins from mouse peritoneal macrophages that were loaded with CE (through incubation with acetylated low density lipoprotein [acetyl-LDL] for 4 days) were compared with those of control macrophages. Densitometric analysis of 2-D gel autoradiograms from the cell lysates revealed statistically significant changes in seven cellular proteins (five decreases and two increases). The changes in protein expression (foam cell versus control) ranged from a 458 +/- 164% (p < 0.001) increase to a 35 +/- 34% (p < 0.001) decrease (n = 11). Incubation of macrophages with beta-very low density lipoprotein, which also increased the CE content of macrophages (albeit to a lesser extent than acetyl-LDL), resulted in changes in five of the seven proteins. In contrast, incubation of cells with LDL, fucoidan, or latex beads, none of which caused CE accumulation, did not lead to significant changes in four of these five proteins. One of these four proteins, which increased fourfold to fivefold in foam cells (M(r) = 49,000; isoelectric point of 6.8), was purified by preparative 2-D gel electrophoresis. Internal amino acid sequence of cyanogen bromide fragments of this protein as well as Western blot analysis identified this protein as an isoform of alpha-enolase. The increased expression of this alpha-enolase isoform, which was seen as early as day 2 of acetyl-LDL incubation of the macrophages, was diminished by including an inhibitor of cholesterol esterification during the acetyl-LDL incubation period. In conclusion, macrophage foam cell formation is associated with distinct changes in protein expression, including a marked increase in an isoform of alpha-enolase, suggesting a specific biological adaptation to CE loading.
BACKGROUND: Mitral valve repair is the procedure of choice to correct mitral regurgitation (MR). Although chordal replacement with expanded polytetrafluoroethylene (ePTFE) has been widely accepted to repair anterior mitral prolapse and other difficult situations, the long-term results of the repair and the fate of ePTFE have not been delineated. METHODS AND RESULTS: From July 1988 to April 1999, 74 patients (49 males, 25 females) aged 17 to 77 years (mean age 55. 3+/-14.8 years) underwent mitral valve repair with chordal replacement with ePTFE. The follow-up period was from 6 months to 11. 3 years (mean 4.6+/-3.2 years). The causes of MR were degenerative in 65 patients (88%) and infective in 9 (12%). Three patients had active infective endocarditis. Valve lesions were anterior in 35 patients, posterior in 10, and both anterior and posterior in 29. Various procedures for plasty of leaflets were necessary in 37 patients (50%). Atrial fibrillation was associated in 38 patients (51%), and the maze procedure has been performed in a selected group of 30 patients (41%) since July 1992. There was 1 in-hospital death (1.4%) and 3 late cardiac deaths (4.1%). More than moderate MR developed in 12 patients (17%) during the follow-up period. Three of these patients required early reoperation within 1 year due to hemolysis. Two patients underwent mitral valve replacement at 6 and 8 years after repair, respectively. The actuarial reoperation-free rates at 5 and 10 years were 94.3+/-2.8% and 81.7+/-9.1%, respectively. Sinus rhythm was restored in 21 patients (70%) with the maze procedure. There was only 1 thromboembolic episode (0. 3%/patient-y) in a patient with atrial fibrillation who did not undergo the maze procedure. Event-free survival rates as assessed by the freedom from cardiac death, thromboembolism, reoperation, and anticoagulation-related hemorrhage at 5 and 10 years were 91.3+/-3. 4% and 71.6+/-9.7%, respectively. There was no relationship between recurrent MR and the change of ePTFE. Structural analysis of the ePTFE resected during reoperation revealed no calcification and showed remaining flexibility and pliability. Protein infiltration was observed in the ePTFE, and collagenous proliferation was recognized at the site of fixation to the valve leaflet and the papillary muscle. The surface of the ePTFE was completely endothelialized, which may induce antithrombogenicity. CONCLUSIONS: The long-term durability and biological adaptation of ePTFE as artificial chordae for mitral valve repair of MR were proved for >10 years.
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