Parvalbumin in mouse muscle in vivo and in vitro

Parvalbumin is a cytosolic calcium-binding protein found in adult fast-twitch mammalian muscle. Using an antibody to paravalbumin, we have shown that its distribution in adult mouse muscles is associated with certain fibre types. It is absent from slow-twitch type 1 fibres, is absent or at low levels in fast-twitch type 2A fibres, but is present at moderate or high levels in fast-twitch type 2B fibres. When adult mouse muscle is cultured with embryonic mouse spinal cord, the regenerated fibres become innervated, express the adult fast isoform of myosin heavy chain and appear histochemically as fast-twitch fibres. We therefore investigated whether these apparently mature fibres also contained parvalbumin. Parvalbumin was not found in any fibres of twenty mature cultures, suggesting that neurotrophic activity in the absence of specific adult nerve activity patterns was insufficient to cause the expression of parvalbumin in the cultures.     

Lactose intolerance in adults in Senegal

The isolated malabsorption of the lactose in the adult is an hereditary feature while is not found often in the white people but is spread out in black Africa. In Senegal, a ratio of about 29% is verified, changing according to the ethnic composition. Only the Peuhls, of semitic origin, show a full tolerance to lactose.     

Fibromodulin gene is expressed in human epidermal keratinocytes in culture and in human epidermis in vivo

Fibromodulin is a small leucine-rich proteoglycan that has a central role in the maintenance of collagen fibrils structure, and in regulation of TGF-β biological activity. Although, it is mainly found in cartilage and tendon, little is known regarding the expression of the fibromodulin gene in other cell types. By RT-PCR, real time PCR and immunohistochemistry, we describe the expression of the fibromodulin gene and the presence of the protein in human epidermal keratinocytes (HEK), both in culture and in normal human epidermis. Our results show, for the first time, that fibromodulin gene is constantly expressed in HEK during culture time. Immunostaining showed that fibromodulin is located intracytoplasmically in basal and stratified keratinocytes of the growing colonies, confluent cultures, and epidermis in vivo. The expression and intracellular localization of fibromodulin in HEK is a new finding and opens new possible biological roles for the SLRP family.     

Asthma in children--problems in diagnosis

Bronchial asthma in children may be difficult to diagnose. Education of the parents regarding allergic conditions, specifically bronchial asthma, is exceedingly important in order to assure satisfactory treatment and clinical results. Chest symptoms of unexplained origin in early life should immediately arouse suspicion of allergic disease. Other causes of asthmatic symptoms must be borne in mind and excluded before a positive diagnosis of bronchial asthma is established. Of the many factors to be considered in investigating a child with asthma, a comprehensive history is most essential. The climate to which the patient is exposed and the psychic influences must be taken into account. Physical examination, x-ray films and laboratory procedures should be carefully executed. Skin testing, especially with food allergens, should not be relied upon to give all the information in allergic disease. Some form of diet trial, such as elimination diets, should be used if sensitivity to food is suspected.     

Studies in biochemical genetics in Drosophila

The metabolism of the imaginal discs of wild type, miniature, vestigial, and four-jointed varieties of Drosophila was investigated using the Cartesian diver ultramicrorespirometer. Wild type and vestigial wing disc respiration is inhibited by cyanide and azide and thus is mediated by an iron or copper porphyrin system, presumable cytochrome-cytochrome oxidase. Respiration is also inhibited by certain hydroxynaphthoquinones, believed to inactivate some enzyme between cytochromes b and c. The respiration of the vestigial and miniature wing discs is increased to normal by the addition of ascorbic acid and to a lesser extent by p-phenylenediamine and hydroquinone, hence the cytochrome oxidase and cytochrome c systems of vestigial and miniature wing discs are normal and the effects of these genes are on enzymes below cytochrome c in the respiratory chain. The respiratory enzymes of the developing imaginal discs of insects are similar to those of a wide variety of cells from bacteria to mammals. The correlation of these biochemical findings with embryological studies of the discs is discussed.     

Trends in consanguinity in South India

This study uses data from the 1992-93 National Family Health Survey to assess trends in consanguinity in the South Indian states of Andhra Pradesh, Karnataka, Kerala and Tamil Nadu. In Kerala, the frequency of consanguineous marriages is very low and one type of preferred marriage of the Dravidian marriage system uncle niece marriage--is conspicuously absent. In the other states of South India, consanguinity and the coefficient of inbreeding are high. While no change in consanguinity is observed during the past three to four decades in Karnataka, a definite decline is observed in Andhra Pradesh and Tamil Nadu. Due to recent changes in the demographic and social situation in these states, this decline in consanguinity is likely to continue.     

Sequence variation in ZFX introns in human populations

DNA variation in human populations was studied by examining the last intron of the ZFX gene (about 1, 151 bp) with a worldwide sample of 29 individuals. Only one polymorphic site was found, which is located in an Alu sequence. This polymorphism is present at an intermediate frequency in all populations studied, and could be a shared polymorphism or due to migration among populations in Asia, Europe, and Africa. The nucleotide diversity is 0.04%, supporting the view that the level of nucleotide variation in nuclear DNA is very low in humans. From the sequence data, the age (T) of the most recent common ancestor of the sampled sequences is estimated: the mode of T is about 306,000 years, and the 95% confidence interval of T is 162,000-952,000 years. This mode estimate is considerably older than the estimates from Y- linked sequences.      

Strongyloides stercoralis genotypes in humans in Cambodia

Little is known about the genetic variability of the soil-transmitted nematode, Strongyloides stercoralis, in humans. We sequenced portions of the small subunit rDNA (SSU), including the hyper variable regions (HVR) I and IV from S. stercoralis larvae derived from individuals living in a rural setting in Cambodia. We identified three polymorphic positions, including a previously reported one within the HVR I. HVR IV was invariable. Six different SSU alleles existed in our sample. Although different genotypes of S. stercoralis were found in the same individuals, no heterozygous larvae were found. This indicates that there is no or very little interbreeding between the different genotypes. Further studies are needed to examine if this is because sexual reproduction, which is facultative, is rare in our study area's S. stercoralis population or because what is considered to be S. stercoralis today is actually a complex of closely related species or subspecies.     

Intraspecific variation in tolerance of warming in fishes

Intraspecific variation in key traits such as tolerance of warming can have profound effects on ecological and evolutionary processes, notably responses to climate change. The empirical evidence for three primary elements of intraspecific variation in tolerance of warming in fishes is reviewed. The first is purely mechanistic that tolerance varies across life stages and as fishes become mature. The limited evidence indicates strongly that this is the case, possibly because of universal physiological principles. The second is intraspecific variation that is because of phenotypic plasticity, also a mechanistic phenomenon that buffers individuals’ sensitivity to negative impacts of global warming in their lifetime, or to some extent through epigenetic effects over successive generations. Although the evidence for plasticity in tolerance to warming is extensive, more work is required to understand underlying mechanisms and to reveal whether there are general patterns. The third element is intraspecific variation based on heritable genetic differences in tolerance, which underlies local adaptation and may define long-term adaptability of a species in the face of ongoing global change. There is clear evidence of local adaptation and some evidence of heritability of tolerance to warming, but the knowledge base is limited with detailed information for only a few model or emblematic species. There is also strong evidence of structured variation in tolerance of warming within species, which may have ecological and evolutionary significance irrespective of whether it reflects plasticity or adaptation. Although the overwhelming consensus is that having broader intraspecific variation in tolerance should reduce species vulnerability to impacts of global warming, there are no sufficient data on fishes to provide insights into particular mechanisms by which this may occur.     

Flow in arteries in the presence of stenosis

Of concern in the paper is a study of blood flow in an arterial segment having a stenosis. The artery is modelled as an initially stressed orthotropic elastic tube filled with a viscous incompressible fluid. The analysis is based on the assumption of the presence of a mild stenosis in the artery. Blood is treated as a Newtonian fluid. The effect of the surrounding connective tissues on the motion of the wall has been incorporated. Propagation of small amplitude harmonic waves, generated due to the flow of blood where the wave length is large compared to the radius of the arterial segment, is is considered in detail.     

On the increase in complexity in evolution

It is argued that complexity, rather than fitness or organization, is the quantity whose increase gives a direction to evolution.The increase in complexity is shown to be a consequence of the process by which a self-organizing system optimizes its organization with respect to a locally defined fitness potential.     

Studies in rapidly labelled ribonucleic acid in cell fractions and in tumour tissues

1. Twenty minutes after injection of [(3)H]orotic acid into rats the rapidly labelled RNA from the liver is mainly associated with the nuclear fraction and little with the ribosomal cytoplasmic fraction. 2. The thermal denaturation of RNA from the fractions was not as reversible as that of the RNA extracted from whole liver. 3. Rapidly labelled RNA is synthesized by cells from a transplantable hepatoma when incubated in the presence of [(3)H]uridine and, after extraction and centrifugation, the label is present in three main fractions: one which sediments to the bottom of a gradient and is associated with DNA, a second which sediments to the heavy side of the 28s RNA, and a third which has a peak of activity between 28s RNA and 18s RNA and is associated with DNA. 4. After labelling and extraction of the RNA from Ehrlich ascites cells the distribution of radioactive components is similar to that of the material from the hepatoma cells. 5. The difference between the tumour cells and liver is due to some extent to the method of homogenizing the tissues and the nature of the components is discussed.     

Chemokines in host-parasite interactions in leishmaniasis

Crucial to the defense against leishmaniasis is the ability of the host to mount a cell-mediated immune response capable of controlling and/or eliminating the parasite. Cell recruitment to the site of infection is essential to the development of the host cellular immune response. The process is controlled by chemokines, which are chemotactic cytokines produced by leukocytes and tissue cells.     

Polymorphism in Cepaea Hortensis in marginal populations in Spain

Cepaea hortensis (Mull) is found in Spain only in the western part of the Iberian mountain range. This is the southernmost limit of its range. The most frequent colour is yellow, brown being very rare. The most frequent band patterns are 12345, fused banded and unbanded. There are associations between maximum and minimum temperatures and pink and effectively unbanded yellow phenotypes. The populations may be grouped into two zones, one located in the north and the other in the south of the sampled area. Visual predation was not observed. The marginal populations studied by us were compared with others from Northern Europe, and it was observed that pink snails are more frequent at the southern limit, and unbanded ones at the northern limit. This was interpreted as a climatic selection.     

Factors affecting DNA synthesis in an in vitro system

Summary Mononucleated striated muscle cells and one type of endoderm can be isolated from anthomedusae and cultivated in artificial sea-water. In the cultivated muscle the differentiated state is maintained. In the cultivated endoderm flagella are formed, but no new cell types differentiate and DNA synthesis or mitosis is not observed. When isolated muscle is grafted upon endoderm, regeneration or formation of new cell types is not observed. Following treatingment with bacterial collagenase DNA synthesis and flagellum formation are initiated in the isolated muscle; in the isolated endoderm, collagenase treatment has no effect. When striated muscle treated with collagenase is grafted upon endoderm, DNA synthesis is observed in the endoderm, and a regenerate is formed involving transdifferentiation. Although desmosomal contact between collagenase treated muslce and the endoderm is established, it is not sufficient to induce DNA synthesis; complete covering of the endoderm by the muscle is required.     

Oogenesis in antenatal development in man

Summary Ninety-seven female embryos and foetuses aged 6–40 weeks were quantitatively analyzed for germ cell development, mitotic activity in the ovary, and dynamics of chromosome transformations in oocytes at the stages of meiotic prophase I and follicle genesis. For the first time, chronology of oocytes dynamics at the stage of the preleptotene chromosome condensation and decondensation is described. Oocytes at the leptotene stage occur in embryos aged 10–11 weeks. Oocyte transfer at the zygotene and pachytene stages starts by 10.5–11 and 11.5–13 weeks, respectively. Their number is maximum after 26 weeks and by the 40th week decreases to just single oocytes. The first oocytes at the diplotene stage appear in foetuses aged 11.5–12 weeks. Oocyte transition to the dictyotene stage is observed in single oocytes after 16 weeks of development, but active bivalent decondensation begins after 26 weeks.The formation of a follicular layer takes place not earlier than around the oocyte at the diplotene stage. Follicle genesis occurs after 11–12 weeks. Transformation of primordial follicles into primary ones is intensified after 19–20 weeks. By the moment of birth, the majority of oocytes in the human ovary are contained in primary follicles, and only a few are contained in primordial ones. The number of secondary and tertiary antral follicles is extremely small. The dynamics of degeneration of germ cells throughout intra-uterine development is also described.     

Jump in transport coefficients in discharges with ECR heating in the T-10 tokamak

Abstrac Transient processes after off-axis ECR heating in the T-10 tokamak is switched on or off are analyzed. It is found that the transient processes have the following two characteristic features. First, transport coefficients undergo a jump, thereby driving the evolution of the initial steady-state distributions of the plasma parameters. Second, the evolution of the original configuration is accompanied by ECR heating of the plasma. A mathematical model is proposed that takes into account the jump in transport coefficients over the entire cross section of the plasma column and adequately describes this transient process. An analysis of the experimental data confirms the validity of the model equations formulated here. It is shown that, without invoking the jump in transport coefficients after off-axis ECR heating is switched on or off, it is impossible to describe the experimentally observed opposite-sign changes in the electron temperature at the center of the plasma column and in the ECR heating region. __________ Translated from Fizika Plazmy, Vol. 28, No. 5, 2002, pp. 403–418. Original Russian Text Copyright ? 2002 by Andreev, Dnestrovskij, Razumova, Sushkov.     

Expression of chick Coactosin in cells in morphogenetic movement

Coactosin is a 17 kDa actin binding protein that belongs to the actin depolymerizing factor/cofilin homology family. Coactosin inhibits barbed‐end capping of actin filament, and is involved in actin polymerization. Coactosin is expressed in cephalic and trunk neural crest cells, cranial ganglia and dorsal root ganglia. Coactosin is also expressed in the cells that are forming mesonephric duct, and endodermal cells. Immunocytochemistry with anti‐Coactosin antibody shows that Coactosin is localized in the cytoplasm, and associated with actin stress fibers in cultured neural crest cells. Coactosin is also expressed in the axon of oculomotor nerve and trigeminal nerve. In the growth cone of the oculomotor nerve axons, both Coactosin mRNA and protein were localized, which is indicative of the role of Coactosin in pathfinding of the growth cone. Coactosin is expressed in those that require dynamic and highly coordinated regulation of actin cytoskeleton, that is, neural crest cells, cells in the tip of the mesonephros, endodermal cells and axons.     

State-Dependent Changes in Auditory Sensory Gating in Different Cortical Areas in Rats

Sensory gating is a process in which the brain’s response to a repetitive stimulus is attenuated; it is thought to contribute to information processing by enabling organisms to filter extraneous sensory inputs from the environment. To date, sensory gating has typically been used to determine whether brain function is impaired, such as in individuals with schizophrenia or addiction. In healthy subjects, sensory gating is sensitive to a subject’s behavioral state, such as acute stress and attention. The cortical response to sensory stimulation significantly decreases during sleep; however, information processing continues throughout sleep, and an auditory evoked potential (AEP) can be elicited by sound. It is not known whether sensory gating changes during sleep. Sleep is a non-uniform process in the whole brain with regional differences in neural activities. Thus, another question arises concerning whether sensory gating changes are uniform in different brain areas from waking to sleep. To address these questions, we used the sound stimuli of a Conditioning-testing paradigm to examine sensory gating during waking, rapid eye movement (REM) sleep and Non-REM (NREM) sleep in different cortical areas in rats. We demonstrated the following: 1. Auditory sensory gating was affected by vigilant states in the frontal and parietal areas but not in the occipital areas. 2. Auditory sensory gating decreased in NREM sleep but not REM sleep from waking in the frontal and parietal areas. 3. The decreased sensory gating in the frontal and parietal areas during NREM sleep was the result of a significant increase in the test sound amplitude.