Lactate dehydrogenase activity in human placenta following exposure to environmental pollutants.

The impact of environmental pollution at the place of residence of pregnant women and of their smoking habits on the cellular energy metabolism of placental tissue was investigated. Samples of full-term placentas were randomly collected from two environmentally different regions of Slovakia (Bratislava, Stará Lubovna) and the activity of lactate dehydrogenase (LDH) was measured. Our results showed enhanced LDH activity in the placenta that was dependent on both the type of environmental pollutants at the place of residence and the smoking habits during pregnancy. The enhanced LDH activity may reflect hypoxic conditions due to the accumulation of heavy metals and toxic compounds of tobacco smoke in the placental tissue. A high content of heavy metal particles, found in placental samples from Stará Lubovna in our previous studies, might contribute to the increased LDH activity in placentas from this region. We hypothesize that fine metal particles deposited in the placental tissue might be phagocytozed by the syncytiotrophoblast, thus contributing to the decreased oxygen level in placental tissue.     

Assessment of pathological changes in fish muscle tissue, forming as a result of exposure to toxic factors in the environment

Our investigation of muscle tissue of fishes, inhabiting the regions with unfavorable ecological conditions (the river Volga), permitted to select four types of degenerative changes in muscle tissue. These alterations are associated with both the phylogenetic status of fish species and ecological dispositions of species. Using different methods of investigation several types of muscle destruction were shown. I. Destruction of myofibrillar apparatus (lysis of protofibrils), with sarcolemma remaining intact. II. Destruction of the myofibrillar apparatus, with sarcolemma, T-system, and sarcoplasmic reticulum being disrupted. III. Invasion of muscle fibers by lymphoid cells and macrophages; with sarcolemma being intact. IV. Lysis of sarcolemma by proteolytic enzymes of lymphoid elements; with muscle fibers being disintegrated. The objects of this study were muscle tissues of 8 fish species (Acipenser gueldenstadti, A. stellatus, A. ruthenus, Lucioprerca lucioperca, Esox lucius, Perca fluviatilis, Tinca tinca, Caprinus carpio). The white muscle degeneration followed the patterns of types I and II, while that of red muscles corresponded to types III and IV. White and red muscles of the Chondrostei fishes (sturgeon, stellate, sterlet) undergo destruction more frequently, than muscles of the Holostei fishes (pike, perch, zander, sazan, tench). Degenerative processes of white and red muscles of fish-eating fishes were more obvious than those of herbivorous fishes.     

Distribution of biomarkers of human exposure to persistent organic pollutants from the group of organohalogen compounds as a result of the impact of the environment

Abstract

Organohalogen compounds constitute one of the important groups of persistent organic pollutants (POPs). Among them, due to their long-term health effects, one should pay attention on polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and perfluoroalkylated substances (PFASs). In case of that anthropogenic group of environmental pollution, the scientific world faces a problem of not only checking their toxic influences on the human organism at different age, from the natal period till late elderly years, but also monitoring the levels of such a numerous group of compounds in various environments, including human tissues and body fluids. This gave birth to a concept of checking the levels of selected biomarkers of exposure in the human organism, calculating body burden and assessing the hazard exposure to human beings. This article is an attempt to answer the question whether testing only biomarkers for different groups of pollutants is enough to determine the threat to different human populations. CB-153 levels represent a significant share in the sum of the six indicator NDL-PCBs (42.96%). In contrary to PCBs, in the case of PBDEs, not only BDE-47 is a biomarker of exposure to the entire PBDEs group, the congener BDE-153 cannot be omitted. Among the compounds belonging to PFASs, only four are detected in the biological material. The PFOS is the dominant representative of this group in the blood samples. It constitutes approximately 75% of the total PFASs.     

Structuro-functional changes of bushy receptors after reoxygenation

With restarting oxygen supply to the bushy receptors of the frog urinary bladder, a gradual increase of impulse frequency in the afferent neural fibers is observed, with a successive exceed, in some cases, of the initial level and rearrangement of spike rhythmicity according to the type of "spasmodic" discharges. Certain acceleration is noted in vital staining and discoloration of the receptors. This is expressed in shortening coloration time, in increasing rate for accumulation restorative equivalents, in intensified granuloformation. Ultrastructural shifts are mainly demonstrated in normalization of the mitochondrial apparatus.     

Structuro-functional changes in bushy interoceptors during protracted anoxia

The bushy receptors of the frog urinary bladder respond to the effect of 60-minute-long anoxia with a complex combination of morphological. tinctorial and electrophysiological reactions. A biphase change in dynamics of bioelectrical activity takes place (an initial increase of frequency with its successive decrease), prolongation of the vital staining periods with methylene blue, change in the character of staining and decoloration of the receptory plates: increase in homogeneity and in intensity of staining, discontinuance of granuloformation and weakening of processes of the plates mobility. The ultrastructural changes are mainly concerned with mitochondria, where either crists reduce and osmiophility decreases, or increases. A part of mitochondria does not change. Certain heterogeneity in reactive changes of the receptors is noted. This is considered as manifestation of functional heterogeneity of the receptory units and their structural elements.     

Protective and adaptive reactions of the air-conducting and respiratory portions of the lungs to exposure to atmospheric pollutants

A complex structural-functional investigation of protective-adaptive reactions of various parts in the lungs has been performed under inhalation of some toxic substances. To a continuous inhalation effect of 1,2-dichlorpropane, 132 non-inbred white rats have been subjected. At the first stage of the investigation, using specific loading tests, periods for formation of increased and decreased resistivity of the experimental animals have been defined. Under the given scheme of the experiment the state of a maximal resistivity develops by the 30th day of the influence, then it gradually decreases and in 60 days becomes significantly lower than in the control animals. Synchronous changes in resistivity and in loading of the respiratory organs are revealed. The structural-functional investigation of the pneumatic and respiratory parts of the lungs during the period of formation (in 5 days of the influence), at maximum (in 30 days of the influence) and at decreased resistivity (in 60 days of the influence) makes it possible to establish that functional activity of the aero-hematic, aero-epithelial barriers and the surfactant system of the lungs increases during the period of elevated resistivity and decreases at the stage of reduced endurance to the loading. A suggestion is made that, together with other factors, increasing functional activity in the systems studied is an essential component for formation of the elevated stability of the organism against toxic inhalation.     

Microbial changes occurring in soil as a result of storage

Summary Changes in numbers of various microbial groups in the interim between collection and analysis of a tropical soil were determined. Although the number of most organisms decreased as a result of storage, the percentage distribution of several groups increased. The greatest decreases occurred in the top layers of soil. Both the numbers and the relative distribution of actinomycetes increased after storage. The possible significance of this increase in the detection of fungistatic materials in soil is discussed. Numbers of fungi were higher after storage in all soil depths, except in the top layer where essentially no change occurred. The vertical distribution and relative frequency of isolation of fungal species after storage is presented. The percentage distribution of spore-forming and CO₂-tolerant bacteria was higher after storage, but that of CO₂-tolerant fungi was lower.The significance of these results in soil microbiological studies, as well as possible causes of the changes, are discussed.     

Vegetation pattern shift as a result of rising atmospheric CO2 in arid ecosystems

Arid ecosystems are expected to be among the ecosystems most sensitive to climate change. Here, we explore via model calculations how regular vegetation patterns, widely observed in arid ecosystems, respond to projected climatic shifts as provided by general circulation model output. In our model, the photosynthesis and respiration terms are explicitly linked to physiological attributes of the plants and are forced with the primary climatic drivers: atmospheric CO₂, air temperature, and precipitation. Under future climate scenarios, our simulations show that the system’s fate depends on whether the enhancements to photosynthesis due to elevated atmospheric CO₂ outweigh the increases in respiration due to higher air temperatures and the increases in water stress due to lower rainfall. A scalar measure is proposed to quantify this balance between the changes in the three climate drivers. Our model results suggest that knowing how the three primary climate drivers are evolving may provide hints as to whether the ecosystem is approaching desertification.     

Vegetation pattern shift as a result of rising atmospheric CO2 in arid ecosystems

Arid ecosystems are expected to be among the ecosystems most sensitive to climate change. Here, we explore via model calculations how regular vegetation patterns, widely observed in arid ecosystems, respond to projected climatic shifts as provided by general circulation model output. In our model, the photosynthesis and respiration terms are explicitly linked to physiological attributes of the plants and are forced with the primary climatic drivers: atmospheric CO₂, air temperature, and precipitation. Under future climate scenarios, our simulations show that the system’s fate depends on whether the enhancements to photosynthesis due to elevated atmospheric CO₂ outweigh the increases in respiration due to higher air temperatures and the increases in water stress due to lower rainfall. A scalar measure is proposed to quantify this balance between the changes in the three climate drivers. Our model results suggest that knowing how the three primary climate drivers are evolving may provide hints as to whether the ecosystem is approaching desertification.     

Unfolding of the bacterial nucleoid both in vivo and in vitro as a result of exposure to camphor.

Both prokaryotic and eukaryotic cells are sensitive to killing by camphor; however, the mechanism by which camphor kills has not been elucidated. We report here that camphor unfolds the nucleoid of Escherichia coli and that unfolding does not require DNA replication, translation, or cell division. We show that exposure of isolated nucleoids to camphor results in unfolding of the chromosome.     

Changes in cyclic AMP concentration of the rat preoptic region as a result of long term exposure to cold

The cAMP concentration in the preoptic region was studied in rats during exposure to low ambient temperature (Ta: -10 degrees C) and after return to control Ta (22 degrees C). With respect to control cAMP concentration, changes were observed consisting of a decrease (delta cAMP: 4.19 /+- 0.15 pM/mg Pr; p < 0.001) at low Ta and an increase (delta cAMP: 1.40 /+- 0.13 pM/mg Pr; P < 0.05) after return to control Ta. In contrast, cortical cAMP concentration decreased both at low Ta (delta cAMP: 2.94 /+- 0.09 pM/mg Pr; P < 0.005) and after return to control Ta (delta cAMP: 3.21 /+- 0.09 pM/mg Pr; P < 0.001). such cAMP changes in the preoptic region may be related to different activation levels of thermoregulatory and sleep mechanisms.     

Physiological changes and gastro-intestinal symptoms as a result of ultra-endurance running

One hundred and seventy-two competitors of the Swiss Alpine Marathon, Davos, Switzerland, 1988, volunteered for this research project. Of these volunteers 170 (158 men, 12 women) finished the race (99%). The race length was 67 km with an altitude difference of 1,900 m between the highest and lowest points. Mean age was 39 (SEM 0.8) years. Average finishing times were 8 h 18 min (men) and 8 h 56 min (women). Loss of body mass averaged 3.4% body mass [mean 3.3 (SEM 0.2)%; 4.0 (SEM 0.4)%; men and women, respectively]. Blood samples from a subgroup of 89 subjects (6 women and 83 men) were taken prior to and immediately after completion of the race. Changes in haemoglobin (9.3 mmol.l-1 pre-race, 9.7 mmol.l-1 post-race) and packed cell volume (0.44 pre, 0.48 post-race) were in line with the moderate level of dehydration displayed by changes in body mass. Mean plasma volume decreased by 8.3%. No significant changes in plasma osmolality, sodium, or chloride were observed but plasma potassium did increase by 5% (4.2 mmol.l-1 pre-race, 4.4 mmol.l-1 post-race). Mean fluid consumption was 3290 (SEM 103) ml. Forty-three percent of all subjects, and 33% of those who gave blood samples, complained of gastro-intestinal (GI) distress during the race. No direct relationship was found between the quantity or quality of beverage consumed and the prevalence of GI symptoms.(ABSTRACT TRUNCATED AT 250 WORDS)