Influence of simulated H component of a typical magnetic storm on early ontogeny of <Emphasis Type="Italic">Daphnia magna</Emphasis> straus

The influence of simulating the H component of a typical magnetic storm on the early ontogeny of Daphnia magna Straus at 21 and 23°C has been studied. Judging by the rates of early development, the effects of the whole magnetic storm experienced by the egg (from the sudden onset to the end) differ from those produced by only the recovery phase. Moreover, the effects essentially depend on the hatching temperature. Early exposure to the whole simulated magnetic storm has remote effects such as changes in the body length in the first progeny broods from the females exposed at the embryo stage.     

Effects of an induced magnetic storm on the early ontogenesis of roach <Emphasis Type="Italic">Rutilus rutilus</Emphasis> (L.)

The influence that an induced magnetic storm (IMS) modeled in a confined volume has on the early ontogenesis of Rutilus rutilus was studied. The significant effects of the IMS were observed for the hatching rate of roach embryos, the size-weight and morphometric parameters of the fry, the variability of the vertebral column, and ontogeny stability in the roach offspring.     

Effect of a magnetic field and copper upon activity of hydrolytic enzymes in roach (Rutilus rutilus) underyearlings

Remote effects of separate and combined exposure to copper (0.001 mg/L and 0.01 mg/L) and a low-frequency magnetic field during early embryogenesis in roach (Rutilus rutilus) underyearlings were studied. The study revealed that exposures lead to changes in the linear and weight parameters, activity of glycosidases, and kinetic characteristics of carbohydrates hydrolysis in the fish intestine. Copper decreases the activity of glycosidases and modifies the effect of a magnetic field. The exposure-induced decrease in the value of the seeming Michaelis constant of carbohydrate hydrolysis indicates the increase in the enzyme-substrate affinity. This phenomenon may be attributed to the adaptive reactions in response to negative effects of copper and a magnetic field during early ontogenesis in roach.     

The electron-microscopic picture of postnatal development of oligodendroglia.

Ultrastructural studies were carried out on the oligodendroglia in the corpus callosum of rat brain in different periods of the animal's extrauterine development. These investigations showed a possibility of distinguishing in the early stages of ontogenesis three forms of oligodendroblasts differing from one another by electron density and the organelle content of the cytoplasm. The beginning of the production of medullary sheaths was noted as early as the first day after birth and the termination of the morphological phase of this process was recorded on the 8th day of postnatal ontogenesis. Moreover, it was found that on the 17th day of the rat's life the process of differentiation of oligodendroglia in the corpus callosum comes to an end.     

Influence of environmental factors in early ontogenesis on aging and life span

A possible dependence of aging and life span in man on specific features of early ontogenesis has been analyzed on the basis of published and author's data. It was shown that the life span depended on climatic factors acting during prenatal and/or early postnatal period. When analyzing a sample of 101,634 humans died in Kiev in 1990-2000, a reliable relationship was established between the age of death and month of birth. The lowest and highest death ages were observed in persons born in April-June and in the end of the year, respectively. The lowest and highest average monthly values of death age differed in men and women by 2.6 and 2.3 years, respectively. In persons survived for more than 60 years, a "birthday" effect was demonstrated: dependence of the mortality level on the month of individual annual cycle was the highest in its first and last month. It has been proposed that this effect is related imprinting of the "birth stress" in the structure of biological rhythms, which may lead to periodic changes in viability during the individual annual cycle. The mechanisms underlying long-term effects of stresses in early ontogenesis have been studied on Drosophila melanogaster. X-irradiation of eggs at 0.50 and 0.75 Gy led to an increased level of survival of imago. The described radiation hormesis was accompanied by an increased resistance of DNA to S1-nuclease, which could be due to a long-term activation of the repair system in irradiated insects. The results obtained suggest that long-term changes in the range of gene expression induced by mild stresses in early ontogenesis can be a key mechanism of early "programming" of the potential of longevity and hormesis for life span.     

Effect of a 60 Hz magnetic field on the behavior of Paramecium

Paramecium multimicronucleatum was used as a model cell to study the effects of 60 Hz magnetic fields on swimming behavior. When exposed to a vertical field of 0.6 T, the cells accumulated at the upper end of the cuvette. An analysis of the swimming behavior revealed that the exposure to the field increased the number of cells swimming upwards maximally at 1 min after onset of the exposure. This effect of the magnetic field was transient, disappearing within a few minutes during the exposure. It is suggested that the magnetic field may amplify to a large extent the negative gravitaxis of Paramecium. Effects of an induced electric field on the swimming behavior are also discussed.     

The role of cardiac magnetic resonance imaging in differentiating the underlying causes of left ventricular hypertrophy

The onset of sudden cardiac death and large inter- and intra-familial clinical variability of hypertrophic cardiomyopathy pose an important clinical challenge. Cardiac magnetic resonance imaging is a high-resolution imaging modality that has become increasingly available in the past decade and has the unique possibility to demonstrate the presence of fibrosis or scar using late gadolinium enhancement imaging. As a result, the diagnostic and prognostic potential of cardiac magnetic resonance imaging has been extensively explored in acute and chronic ischaemic cardiomyopathy, as well as in several nonischaemic cardiomyopathies. This review aims to provide a critical overview of recently published studies on hypertrophic cardiomyopathy and discusses the role of cardiac magnetic resonance imaging in differentiating underlying causes of hypertrophic cardiomyopathy, such as familial hypertrophic cardiomyopathy, cardiac involvement in systemic disease and left ventricular hypertrophy due to endurance sports. Also, it demonstrates the use of cardiac magnetic resonance in risk stratification for the onset of sudden cardiac death, and early identification of asymptomatic family members of hypertrophic cardiomyopathy patients who are at risk for the development of hypertrophic cardiomyopathy. (Neth Heart J 2010;18:135-43.)     

Stochastic mechanism of cellular aging--abrupt telomere shortening as a model for stochastic nature of cellular aging

A strong stochastic component has been described for the appearance of senescent cells in cultures that have not completed their in vitro lifespan. The proliferative potential of individual clones show a bimodal distribution. Additionally, two cells arising from a single mitotic event can exhibit large differences in their doubling capacities. In this report we present a model and a computer simulation of the model that explains the observed stochastic phenomena. The model is based on both gradual and abrupt telomere shortening.Gradual telomere shortening (GTS) occurs during each cell division as a consequence of the inability of DNA polymerase to replicate the very ends of chromosomal DNA. It is responsible for the gradual decline in proliferative potential of a cell culture, but does not explain the stochastic aspects of cellular aging. Abrupt telomere shortening (ATS) occurs either through DNA recombination or nuclease digestion at the subtelomeric/telomeric border region of the chromosome. Recombination involves the invasion of a telomere single-strand three-prime protruding end at this border in the telomere of the same chromosome or in another subtelomeric/telomeric region. Shortening of one or more telomeres in the cell causes a sudden onset of cell senescence, referred to as sudden senescence syndrome (SSS). This is manifested as a stochastic and abrupt transition of cells from the larger to the smaller proliferative potential pool and can cause cell cycle arrest within one cell division. The computer simulation matches well with experimental data supporting the prediction that abrupt telomere shortening underlies the stochastic onset of cell senescence. Sudden senescence syndrome appears to be the most important mechanism in the control of the extent of proliferation of a cell culture because it prevents virtually every cell in the culture from reaching its maximum doubling capacity, that would otherwise be allowed by telomere shortening via the end-replication mechanism alone.     

The development of thalamocortical connections studied by using carbocyanine dyes in the early ontogeny of rats]

We studied the differentiation of neurons and development of their connections in the occipital cortex and thalamic areas of the brain in early ontogenesis of rats: from day 11 of embryogenesis until day 19 of postnatal development. We used the method of staining of brain tissues by carbocyanine dyes after its preliminary fixation in aldehydes. Three carbocyanine dyes were used: DiI, DiO and DiA. We showed the dynamics of structural differentiation of the cortical neurons and lateral geniculate body of the thalamus and the specificity of formation of the axonal pathways between the neocortex and thalamic areas. The results obtained confirmed the hypothesis on ordered spatial-temporal growth of the cortical and thalamic fibers in early embryogenesis and revealed synchronous development of both classes of neurons of the lateral geniculate body. Retrograde and anterograde staining of the nerve cells processes by DiI and DiO showed fine morphological details of their structure. DiI provided for a good staining of the cells until day 19 of postnatal ontogenesis and DiO, until the end of embryogenesis, while DiA was not capable of diffusion in the fixed tissue.     

Behaviour of trout (Salmo trutta L.) larvae and fry in a constant magnetic field

Effects of a constant magnetic field on the selection of swimming direction by trout (Salmo trutta L.) larvae and fry were investigated in an experimental facility consisting of chambers equipped with magnets as well as magnet‐free chambers placed at the entrance. The experiments showed a close relationship between the direction selected by the larvae and fry and the presence or absence of ferritic magnets generating a constant magnetic field. The results obtained indicate during early ontogenesis, when a newly hatched individual is no longer an embryo but also not a mature form, that the larva is sensitive to a magnetic field. This sensitivity seems to be related to an exteroreception system that develops at that time involving magnetoreceptors containing magnetite particles.     

Modulation of energy metabolism of lymphocytes in children by natural physical factors]

The aim of this work is exploration of natural physical factors influencing change of age-dependent energy exchange parameters (e.g. activity of SDG) in healthy and premature children. 35 healthy and 35 premature children were investigated over 11 years from early antenatal and postnatal period. Cytochemical investigations were carried out 1-2 time a year until 6 years of age. Solar activity, geomagnetic excitability, air temperature and atmospheric pressure and its diurnal variation on index represented environmental factors. It is suggested that quiet magnetic field might be a predictor of higher level of SDG activity and vice versa. Higher activity of magnetic field leads to displacement of maximum-age of SDG activity to an earlier age. Lymphocytes react to magnetic storm in a phasic manner. Other physical environmental factors might have reciprocal effect so that some of them could negate the effect of others. If intrauterine development took place in a year of higher solar activity, early-development results. However, later development is characterized by lower level of SDG activity. On premature children, as well as in healthy subjects, the more influencing factors on energetic age-dependent parameters are geomagnetic field and variation of atmospheric SDG activity in healthy children is within normal range (and has a training effect), while in premature children depression of hydrogenase in the end stage.     

Formation of diffuse neuroendocrine system in human ontogenesis

The review of literature presents data on formation of the diffuse neuroendocrine system (DNES) in human early ontogenesis and its role in development of organs and vitally important functional systems of the fetus. It is emphasized that impairment of structural development and/or changes of the functional state of DNES cells under effects of unfavorable environmental factors can underlie embryopathies, fetopathies, and disorders of early postnatal adaptations of children.     

The effect of a typical magnetic storm on mitosis in the embryo cells and the length and weight of roach (Rutilus rutilus L.) prolarvae

The action of the tested variants of a typical magnetic storm (MS) has a biological effect on cellular and organismal levels in the prolarva stage. The impact of this environmental factor leads to increased mitotic activity in blastocysts, it can trigger the early hatching of embryos, and it has no negative impact on the size-weight characteristics of free embryos.     

Diverse development and higher sensitivity of the circadian clocks to changes in maternal-feeding regime in a rat model of cardio-metabolic disease

Spontaneously hypertensive rats (SHR) develop cardiovascular and metabolic pathology in adulthood when their circadian system exhibits significant aberrances compared with healthy control rats. This study was aimed to elucidate how the SHR circadian system develops during ontogenesis and to assess its sensitivity to changes in maternal-feeding regime. Analysis of ontogenesis of clock gene expression rhythms in the suprachiasmatic nuclei, liver and colon revealed significant differences in SHR compared with Wistar rats. In the suprachiasmatic nuclei of the hypothalamus (SCN) and liver, the development of a high-amplitude expression rhythm selectively for Bmal1 was delayed compared with Wistar rat. The atypical development of the SHR circadian clocks during postnatal ontogenesis might arise from differences in maternal behavior between SHR and Wistar rats that were detected soon after delivery. It may also arise from higher sensitivity of the circadian clocks in the SHR SCN, liver and colon to maternal behavior related to changes in the feeding regime because in contrast to Wistar rat, the SHR SCN and peripheral clocks during the prenatal period and the hepatic clock during the early postnatal period were phase shifted due to exposure of mothers to a restricted feeding regime. The maternal restricted feeding regime shifted the clocks despite the fact that the mothers were maintained under the light/dark cycle. Our findings of the diverse development and higher sensitivity of the developing circadian system of SHR to maternal cues might result from previously demonstrated differences in the SHR circadian genotype and may potentially contribute to cardiovascular and metabolic diseases, which the animal model spontaneously develops.     

Chondroitin sulfates in developing mouse tooth germs

The role of glycosaminoglycans and proteoglycans during ontogenesis is not known. The developing tooth offers a potentially important model for studies of structure-function relationships. In this study, we have analysed the temproal and spatial expression of chondroitins of differing sulfation patterns in embryonic molars and incisors. For this purpose, we have used monoclonal antibodies (Mabs) specific for unsulfated, 4-sulfated, and 6-sulfated forms of chondroitin in conjunction with indirect immunofluorescence or immunoperoxidase labeling. Unsulfated chondroitin was not detected in embryonic teeth. Chondroitin 4- and chondroitin 6-sulfates were present in the stellate reticulum but otherwise they were confined to the dental mesenchyme. The 3B3 and MC21C-epitope, which are markers of 6-sulfated chondroitin, were uniformly distributed in the dental mesenchyme during the bud stage; they disappeared from the dental papilla of the cusps and of the anterior region of the incisor as development proceeded. These epitopes were absent from the basement membrane and from the predentin. In the odontoblastic cell lineage, the 3B3 and MC21C-epitopes were detected only between preodontoblasts at an early stage of differentiation. The monoclonal antibody 2B6 served as a probe to localize chondroitin 4-sulfate. This glycosaminoglycan was detected as early as the dental lamina stage but its expression was restricted to the basement membrane of the teeth until the late bell stage. After the onset of cusp formation, strong staining was also observed over the occlusal region of the dental papilla while the cervical region of the dental papilla remained 2B6-negative. Incisors at the bell stage exhibited a decreasing gradient of immunostaining by 2B6 from their anterior region to their posterior end. The extracellular matrix surrounding preodontoblasts reacted with 2B6 and the predentin, produced by the odontoblasts, was also intensely labeled with this antibody. Comparison between immunostaining with 3B3 and 2B6, on consecutive sections revealed a mutually exclusive pattern of distribution of the corresponding epitopes during odontogenesis. Furthermore, in the continuously growing incisor, a striking positive correlation was found between the immunostaining patterns produced by 3B3 and MC21C and the mitotic indices along the anterior-posterior axis of the tooth. Hence, sulfation of chondroitin seems developmentally regulated. We postulate that changes in the sulfation pattern of chondroitin might play a role in ontogenesis by locally altering the functional properties of the extracellular matrix.     

Lessons from the Tōhoku tsunami: A model for island avifauna conservation prioritization

Earthquake‐generated tsunamis threaten coastal areas and low‐lying islands with sudden flooding. Although human hazards and infrastructure damage have been well documented for tsunamis in recent decades, the effects on wildlife communities rarely have been quantified. We describe a tsunami that hit the world's largest remaining tropical seabird rookery and estimate the effects of sudden flooding on 23 bird species nesting on Pacific islands more than 3,800 km from the epicenter. We used global positioning systems, tide gauge data, and satellite imagery to quantify characteristics of the Tōhoku earthquake‐generated tsunami (11 March 2011) and its inundation extent across four Hawaiian Islands. We estimated short‐term effects of sudden flooding to bird communities using spatially explicit data from Midway Atoll and Laysan Island, Hawai'i. We describe variation in species vulnerability based on breeding phenology, nesting habitat, and life history traits. The tsunami inundated 21%–100% of each island's area at Midway Atoll and Laysan Island. Procellariformes (albatrosses and petrels) chick and egg losses exceeded 258,500 at Midway Atoll while albatross chick losses at Laysan Island exceeded 21,400. The tsunami struck at night and during the peak of nesting for 14 colonial seabird species. Strongly philopatric Procellariformes were vulnerable to the tsunami. Nonmigratory, endemic, endangered Laysan Teal (Anas laysanensis) were sensitive to ecosystem effects such as habitat changes and carcass‐initiated epizootics of avian botulism, and its populations declined approximately 40% on both atolls post‐tsunami. Catastrophic flooding of Pacific islands occurs periodically not only from tsunamis, but also from storm surge and rainfall; with sea‐level rise, the frequency of sudden flooding events will likely increase. As invasive predators occupy habitat on higher elevation Hawaiian Islands and globally important avian populations are concentrated on low‐lying islands, additional conservation strategies may be warranted to increase resilience of island biodiversity encountering tsunamis and rising sea levels.     

Development of different types of muscle fiber in the postnatal ontogeny of guinea pigs

As demonstrates estimation of myosin ATPase and SDG activity, the guinea pig is already born with differentiated muscle fibers (MF), and the first histochemical differences between them take place in the uterine 10 days before birth. Tonic oxidative fibers of the first type, arranging hexagonally, develop especially quickly at early stages of postnatal ontogenesis. Their relative contents up to the end of the observations (185 days) do not change, and area of their transversal section increases but slightly in comparison to the phasic fibers. The main age changes of the muscle tissue are connected with formation and rearrangement of the phasic fibers. The most intensive reconstructions of the phasic fibers coincide with the period of game activity and sex maturation. In mixed muscles the part of the glycolytic fibers increase during the postnatal ontogenesis. In the process of ontogenesis the soleus muscle fully consists of oxidative fibers. The definitive level of the MF development is established after the guinea pigs have reached their sex maturation. Comparing the results of the given investigation with the previous data on development of MF in rats, it is possible to conclude that term and premature animals have various rates in development of the muscle system, however, main stages of myogenesis coincide, though they are connected with various phases of ontogenesis.     

Formation of the microcirculatory bed of the muscle coat of the wall of the sigmoid colon during human fetal development]

During intrauterine life microcirculatory bed of the muscular coat is forming and developing in accordance with its differentiation, growth and functional changes at various steps of its ontogenesis. This step-like differentiation in the parts composing the microcirculatory bed and the whole microcirculatory network of longitudinal and circulatory layers of the muscular coat is genetically connected with differentiation taking place in the wall of the sigmoid colon during the developmental period studied and, in the end, reflects morphological maturation of the sigmoid colon at different stages of its individual ontogenesis.     

Peroxidase activity and isoenzyme patterns in wheat during ontogenesis

Protein content, total and specific peroxidase activity and isoperoxidase patterns were determined in crude protein preparations from individual parts of field-grown wheat (Triticum aestivum L., cv. Jubilar). Protein content in roots, leaves, and stalks increased at the beginning of ontogenesis and then decreased from 6th, 9th, and 10th development phase (according to Feekes), respectively. Steady increase of the protein content in the ears was observed. Highest peroxidase activity was found in the roots; it diminished from the onset of ontogenesis till maturity of the plants. In the leaves and stalks a slight decrease of peroxidase activity till the 10th development phase and then an increase till maturity was found. The ears exhibited a gradual increase of peroxidase activity. The course of specific peroxidase activity was found to be very similar to that of total activity. Isoperoxidase patterns did not change significantly. In the leaves, a decrease of activity of C₄ and C₅ isoperoxidases was recorded. In the stalks, C l isoenzyme emerged at the end of ontogenesis. A gradual increase of A₁ and A₅ isoperoxidase intensity took place both in the leaves and stalks.