Analyse des procédures du test de Hühner ou test postcoïtal tel qu'il est pratiqué en région Alsace

The Huhner test is an easy, unpainful, unexpensive test which must be done first at the time of unfertility exploration. His clinical and prognosticated interest is much debated because many imprecisions in its realisation and interpretation occur. Our multicentric study proves that this test is quite standardized in his realisation but a loss of its efficacity appears by the fact of a inadequate collaboration between attending physicians and biologists.     

A novel family of linear plasmids with homology to plasmid pAL2-1 of Podospora anserina

Three recently isolated wild-type strains of the ascomycete Podospora anserina were analyzed for the presence of linear mitochondrial plasmids. In one of these strains, designated Wa6, at least 12 distinct plasmid-like elements were identified. From molecular analyses a minimum number of 78 individual linear molecules with proteins bound to their 5 ends was estimated. In addition, the different members of this family of typical linear plasmids were shown to possess a common central region and terminal sequences which differ from one plasmid to another due to the presence of different numbers of a 2.4 kb sequence module. Finally, the pWa6 plasmids share a high degree of sequence similarity with pAL2-1, a linear plasmid previously identified in mitochondria of a long-lived mutant of P.anserina. A mechanism is proposed which explains the generation of these distinct, closely related extrachromosomal genetic traits.     

Definition of constitutive gene expression in plants: the translation initiation factor 4A gene as a model

The NeIF-4A10 gene belongs to a family of at least ten genes, all of which encode closely related isoforms of translation initiation factor 4A. The promoter region of NeIF-4A10 was sequenced, and four mRNA 5 ends were determined. Deletions containing 2750, 689 and 188 bp of untranscribed upstream DNA were fused to the GUS reporter gene and introduced into transgenic tobacco. The three constructs mediated GUS expression in all cells of the leaf, stem and shoot apical meristem. Control experiments using in situ hybridization and tissue printing indicated that the observed GUS expression matches the expression patterns of NeIF-4A mRNA and protein. This detailed analysis at the level of mRNA, protein and reporter gene expression shows that NeIF-4A10 is an ideal constitutively expressed control gene. We argue that inclusion of such a control gene in experiments dealing with specifically expressed genes is in many cases essential for the correct interpretation of observed expression patterns.     

Calcitonin gene-related peptide and its receptor in the thymus

Calcitonin gene-related peptide (CGRP), a 37-amino acid residue neuropeptide, was immunostained in rat thymus at two sites: a subpopulation of thymic epithelial cells, namely subcapsular/perivascular cells, were heavily stained besides some nerve fibers surrounding arteries and arterioles. The administration of nanomolar concentrations of rat -CGRP dose-dependently raised intracellular cyclic adenosine monophosphate (cAMP) levels in isolated rat thymocytes (half-maximum stimulation 1 nM) but not in cultured rat thymic epithelial cells. Peptides structurally related to CGRP (i.e., rat calcitonin or amylin) had no effect. CGRP(8–37), an N-terminally truncated form, acted as an antagonist. Peripheral blood lymphocytes did not respond to CGRP, suggesting that receptors are present only on a subpopulation of thymocytes but not on mature T cells. This was substantiated by visualization of CGRP receptors on single cells by use of CGRP-gold and -biotin conjugates of established biological activity: only a small proportion of isolated thymocytes was surface labeled. In situ, the CGRP conjugates labeled receptors on large thymocytes residing in the outer cortical region of rat thymus pseudolobules. Thus, immunoreactive CGRP is found in subcapsular/perivascular thymic epithelial cells and acts via specific CGRP receptors on thymocytes by raising their intracellular cAMP level. It is suggested that CGRP is a paracrine thymic mediator that might influence the differentiation, maturation, and proliferation of thymocytes.     

A GENETIC PERSPECTIVE OF MAMMALIAN VARIATION AND EVOLUTION IN THE INDONESIAN ARCHIPELAGO: BIOGEOGRAPHIC CORRELATES IN THE FRUIT BAT GENUS CYNOPTERUS

This study investigated allozyme and morphometric variability within the genus Cynopterus, with particular emphasis on C. nusatenggara, which is endemic to Wallacea, the area encompassing the Oriental-Australian biogeographic interface. The genetic distances between Cynopterus species are small by mammalian standards and suggest that this genus has undergone a recent series of speciation events. The genetic distance between populations of C. nusatenggara is strongly correlated with both the contemporary sea-crossing distance between islands and the estimated sea crossing at the time of the last Pleistocene glacial maximum, 18,000 b .p . This observation, together with low levels of population substructure within islands as shown by F-statistics, indicates that the sea is a primary and formidable barrier to gene exchange. The genetic distance and the great-circle geographical distance between the populations of C. nusatenggara are not correlated, although a principal-coordinates analysis of genetic distance reveals relationships between the populations that are similar to their geographical arrangement. A strong negative correlation exists between the level of heterozygosity within island populations of C. nusatenggara and the minimum sea-crossing distance to the nearest large source population. This is interpreted as reflecting an isolation effect of the sea, leading to reduced heterozygosity in populations that have larger sea barriers between them and the large source islands. Independently of this, heterozygosity is negatively associated with longitude, which in turn is associated with systematic changes in the environment such as a gradual decline in rainfall from west to east. The association between heterozygosity and longitude is interpreted as reflecting an association between genetic and environmental variance and supports the niche-width theory of genetic variance. Morphometric variability did not show any of the main effects demonstrated in the genetic data. Furthermore, there was no evidence that, at the level of individuals, genetic and morphometric variability were associated.     

Measurement of 15N-1H coupling constants in uniformly 15N-labeled proteins: Application to the photoactive yellow protein

A modified HNHB experiment is presented that allows thedetermination of J(NH) coupling constants directly from the ratio ofcross-peak to diagonal-peak intensities. The experiment was applied to thephotoactive yellow protein (PYP) and yielded the magnitude of 117³J(NH) coupling constants. In addition, 29³J(NH^(i–1)) coupling constantscould be measured, providing information about the backbone angle .These data, in conjunction with the magnitudes of the³J(H^NH) coupling constantsobtained from the HNHA spectrum, effectively discriminate the twopossibilities for the stereospecific assignment of theH resonances in glycine residues. For all eight glycineresidues in PYP that were not subject to conformational averaging and hadnon-degenerate H resonance frequencies, the J-couplingdata, together with limited NOE data, yielded the stereospecific assignmentof the H resonances for these residues. In addition,reliable and precise , dihedral constraints were also derived forthese residues from the J-coupling data.     

Stable carbon isotopes in tree rings of beech: climatic versus site-related influences

 Stable carbon isotopes in tree rings are a promising tool in palaeoclimate research, provided attempts are made to disentangle climatic from local effects (e.g. soil properties, competition, light). The ¹³C/¹²C variations in cellulose of tree rings of beech (Fagus sylvatica) were determined at several sites in the Swiss Central Plateau covering the last 50 years. We chose sites which differ in moisture conditions and sampled cores from four to six trees per site. The mean ¹³C/¹²C series from the different dry sites (distant by up to 40 km) are closely interrelated suggesting a common external cause. Correlation analysis with climate data proved the total precipitation in the months May, June and July to have the strongest effect on the carbon isotopes (r =  – 0.73). This result is in agreement with the commonly used model which relates the isotope discrimination to the water use efficiency. On the other hand, the isotope series of the wet sites are not as well correlated to the climate. At two of the sites (a dry and a humid) tree ring width suddenly increased. We used this effect as a test-case to study the influence of local growth conditions on the climate-isotope relationship. Received: 17 April 1996 / Accepted: 2 September 1996     

Actions and interactions of growth hormone and insulin-like growth factor-II: body and organ growth of transgenic mice

To characterize long-term actions and interactions of growth hormone (GH) and insulin-like growth factor-II (IGF-II) on postnatal body and organ growth, hemizygous phosphoenolpyruvate carboxykinase (PEPCK)-human IGF-II transgenic mice were crossed with hemizygous PEPCK-bovine GH transgenic mice. The latter are characterized by two-fold increased serum levels of IGF-I and exhibit markedly increased body, skeletal and organ growth. Four different genetic groups were obtained: mice harbouring the IGF-II transgene (I), the bGH transgene (B), or both transgenes (IB), and non- transgenic controls (C). These groups of mice have previously been studied for circulating IGF-I levels (Wolf et al., 1995a), whereas the present study deals with body and organ growth. Growth curves (week 3 to 12) were estimated by regression with linear and quadratic components of age on body weight and exhibited significantly (p < 0.001) greater linear coefficients in B and IB than in I and C mice. The linear coefficients of male I and C mice were significantly (p < 0.001) greater than those of their female counterparts, whereas this sex-related difference was absent in the bGH transgenic groups. The weights of internal organs as well as the weights of abdominal fat, skin and carcass were recorded from 3.5- to 8- month-old mice. In addition, organ weight-to-body weight-ratios (relative organ weights) were calculated. Except for the weight of abdominal fat, absolute organ weights were as a rule significantly greater in B and IB than in I and C mice. IGF-II overproduction as a tendency increased the weights of kidneys, adrenal glands, pancreas and uterus both in the absence and presence of the bGH transgene. Analysis of relative organ weights demonstrated significant (p < 0.05) effects of elevated IGF- II on the relative growth of kidneys (males and females) and adrenal glands (females), confirming our previous report on organ growth of PEPCK-IGF-II transgenic mice. In females, IGF-II and GH overproduction were additive in stimulating the growth of spleen and uterus, providing evidence for tissue-specific postnatal growth promoting effects by IGF-II in the presence of elevated IGF-I     

Are Elevated Aminotransferases and Decreased Bilirubin Additional Characteristics of the Metabolic Syndrome?

Abnormal liver tests, as well as morphological changes in the liver, are frequent among obese patients. Other frequent disturbances are visceral fat accumulation, insulin resistance, non-insulin-dependent diabetes mellitus (NIDDM), hypertriglyceridemia, and hypertension; these are a set of aberrations known as the metabolic syndrome. In order to investigate a possible relationship between the metabolic syndrome and impaired liver status we examined associations between liver tests, metabolic variables (insulin, glucose, and triglycerids), body composition and nutrition in 1083 men (BMI 28.8–63.8 kg/m²) and 1367 women (BMI 26.7–68.0 kg/m²) in the ongoing intervention study of Swedish Obese Subjects (SOS). Standard biochemical techniques were used to assess liver status and metabolic variables. Lean body mass (LBM) and masses of visceral and subcutaneous adipose tissue (AT) were estimated by means of computed tomography (CT) calibrated anthropometric equations. In both genders aspartate aminotransferase and alanine aminotransferase were, or tended to be, positively correlated to fasting serum insulin, visceral AT (women), and alcohol intake. In women, the aminotransferases were also correlated with fasting blood glucose. In both genders alkaline phosphatase was, or tended to be, positively associated with visceral AT, insulin (women), and glucose. Bilirubin was negatively correlated to insulin and visceral AT in men and women. Additional multivariate analyses indicated that alcohol had less explanatory power than serum insulin for the examined liver tests, especially among women. These results suggest that pathological liver tests in the obese may represent an expression of the metabolic syndrome.