Consistency of thrombophilia testing in a reference center according to the current guidelines.

OBJECTIVE: The clinical relevance of hereditary thrombophilia (HT) testing in venous thromboembolic disease (VTE) is limited to specific guidelines. The present study aimed to evaluate the consistency of HT prescriptions in clinical practice according to the current French guidelines. METHODS: This study was conducted from April 2017 to February 2018 in a specialized haemostasis centre and included 58 consecutive patients referred by their clinicians for thrombophilia screening (56 patients following a personal VTE event and 2 asymptomatic relatives of a first-degree patient who had had VTE). One experienced clinician met every patient and assessed a pre-test prediction for the presence or absence of HT based on the clinical characteristics of VTE which was compared to the HT biological results. RESULTS: Among the 58 patients referred to our specialized haemostasis centre, 60% were outside the scope of recommendations for thrombophilia screening. Eight patients were diagnosed with HT. Six out of 8 (75%) patients with diagnosed HT had a history of unprovoked VTE event. Familial history with VTE was a poor predictor for positive HT testing among relatives. The positive and negative predictive values of the clinical prediction were respectively of 19% and 89%. CONCLUSION: The present results underline that screening for HT remains too largely prescribed. Pre-test physician's feeling for the presence of HT was neither sensitive nor specific. Increasing physicians' awareness on this issue and current recommendations should limit prescriptions of HT tests while providing the best possible care for patients with VTE.

Northeastern North America as a potential refugium for boreal forests in a warming climate.

High precipitation in boreal northeastern North America could help forests withstand the expected temperature-driven increase in evaporative demand, but definitive evidence is lacking. Using a network of tree-ring collections from 16,450 stands across 583,000 km(2) of boreal forests in Québec, Canada, we observe a latitudinal shift in the correlation of black spruce growth with temperature and reduced precipitation, from negative south of 49°N to largely positive to the north of that latitude. Our results suggest that the positive effect of a warmer climate on growth rates and growing season length north of 49°N outweighs the potential negative effect of lower water availability. Unlike the central and western portions of the continent's boreal forest, northeastern North America may act as a climatic refugium in a warmer climate.

[CT angiography of the neck: technical considerations]. / Technique d'exploration des vaisseaux cervicaux et encéphaliques: angioscanner.

Examination of acute stroke by CT angiography is an alternative to MRI. Technological improvement of multidetector CT scanners allows neuroimaging of stroke in a multimodal protocol including plain CT, cerebral CT perfusion and CT angiography of the cervical and intracranial arteries. CT angiography is a reliable non invasive technique for the evaluation both extracranial and intracranial vessels that may be used as an alternative to MR angiography.

Fluctuations of climatic conditions, elemental cycling and forest growth at the watershed scale.

The relationships between fluctuations in climatic conditions, forest productivity and elemental cycling were studied from 1994 to 1997 in a headwater catchment of the southern Laurentians dominated by sugar maple (Acer saccharum Marsh.) growing on podzolic soils. Annual budgets show that H+, K, and NO3 were retained in the watershed while Ca, Mg and Na were lost. The magnitude of the net annual budget for Ca, Mg and Na was correlated to annual variations in precipitation with the absolute budget value decreasing during dry years. Stemwood (r2 = 0.85) and total tree biomass production (r2 = 0.99) were correlated with mean annual temperature but fine roots and leaf litter were not. During the growing season, the pH of the organic horizons (FH) decreased as the volumetric water content of soil decreased. A positive association was also found between air temperature and H2O-soluble (r2 = 0.88) and PO4-extractable (r2 = 0.99) SO4 in the upper B horizon. On a multiyear scale, we suspect that the decrease in the storage of inorganic SO4 in the soil results from the cumulative effects of annual variations in climatic conditions superimposed on the long-term decrease in SO4 deposition from the atmosphere. These soil changes were reflected by a decline in SO4, Ca and Mg concentrations in the stream. The generalisation of the observed short-term patterns to longer time scales must be approached with caution. Yet, our results indicate that the associations between climatic variations and the biogeochemistry of the ecosystem occur at different spatial and temporal scales and integrate a broad range of chemical components and ecosystem compartments. This reflects the inherent complexity of natural systems and offers a vast palette of indicators of the response of terrestrial ecosystems to variations in the intensity of environmental factors such as climatic conditions.

Impressions of breastfeeding information and support among first-time mothers within a multiethnic community.

The purpose of this study was to document mothers' perceptions of breastfeeding information and support received from hospital- and community-based health professionals within a multiethnic community. A telephone survey was conducted to assess: mothers' impressions of professional support for breastfeeding, whether recommended breastfeeding practices were followed by health professionals, and the nature and sources of breastfeeding information received. An ethnically diverse sample of 108 first-time breastfeeding mothers was surveyed at 3 weeks postpartum. Overall, the mothers' evaluations of professional support for breastfeeding were positive, even though they reported breastfeeding practices that fell short of recommended standards. Immigrant mothers were found more likely to experience hospital practices detrimental to breastfeeding success than Canadian-born mothers, but were also found more likely to receive professional breastfeeding support in the community. Significant differences were also found between immigrant and Canadian-born mothers in the sources of their breastfeeding information. The findings underscore the key role of nurses in ensuring the promotion and optimal support of breastfeeding.

Measurement and classification of retinal vascular tortuosity.

Automatic measurement of blood vessel tortuosity is a useful capability for automatic ophthalmological diagnostic tools. We describe a suite of automated tortuosity measures for blood vessel segments extracted from RGB retinal images. The tortuosity measures were evaluated in two classification tasks: (1) classifying the tortuosity of blood vessel segments and (2) classifying the tortuosity of blood vessel networks. These tortuosity measures were able to achieve a classification rate of 91% for the first problem and 95% on the second problem, which confirms that they capture much of the ophthalmologists' notion of tortuosity. Finally, we discuss how the accuracy of these measures can be influence by the method used to extract the blood vessel segments.

Automated measurement of retinal vascular tortuosity.

Automatic measurement of blood vessel tortuosity is a useful capability for automatic ophthalmological diagnostic tools. We describe a suite of automated tortuosity measures for blood vessel segments extracted from RGB retinal images. The tortuosity measures were evaluated in two classification tasks: (1) classifying the tortuosity of blood vessel segments and (2) classifying the tortuosity of blood vessel networks. These tortuosity measures were able to achieve a classification rate of 91% for the first problem and 95% on the second problem, which confirms that they capture much of the ophthalmologists' notion of tortuosity.

Clinicopathologic correlation in erythema multiforme and Stevens-Johnson syndrome.

BACKGROUND AND DESIGN: To confirm the recent hypothesis that the spectrum of severe erythema multiforme (EM) is actually composed of two different disorders, we retrospectively studied 38 such cases, particularly in regard to their histopathologic features. Based on photographs and a recent proposal, the cases were classified as EM major when the eruption consisted of typical or raised atypical target lesions located on the extremities and/or the face or as Stevens-Johnson syndrome when the eruption consisted of flat atypical target lesions or purpuric macules that were widespread or distributed on the trunk. The cases were also assessed for causal agent. A biopsy specimen was obtained in each case. Several histologic parameters were analyzed (and scored) without clinical data and correlated to the clinical pattern. These parameters were first studied in a global assessment and then in a detailed evaluation. RESULTS: The global assessment showed two different histological patterns: (1) a predominantly inflammatory pattern characterized by a lichenoid infiltrate and epidermal necrosis that mainly affected the basal layer; and (2) a predominantly necrotic pattern in which major epidermal necrosis and minimal inflammatory infiltration were found. The former pattern was associated with EM major, the latter with Stevens-Johnson syndrome (P < .001) and with drug-related cause (P < .001). The detailed evaluation showed also less epidermal necrosis, and more dermal inflammation, and more exocytosis in EM major. Conversely, there was more epidermal necrosis, less dermal inflammation, and less exocytosis in Stevens-Johnson syndrome. The difference was statistically significant for the inflammation and exocytosis. CONCLUSIONS: This study suggests that the two different symptomatologies in the spectrum of severe EM correlate with two different patterns of histopathologic changes. A prospective multicentered study should be conducted to definitively characterize these entities.

Double rotation and magic-angle spinning nuclear magnetic resonance study of 27Al: reexamination of the aluminium borate 9Al2O3.2B2O3.

27Al nuclear magnetic resonance spectra of polycrystalline aluminium borate 9Al2O3.2B2O3 have been measured in double rotation at 11.7 and 7.0 T and high-speed magic-angle spinning at 7.0, 9.4, 11.7, 14.1 and 17.6 T. Spinning sidebands from the satellite transitions were observed at 7.0 and 14.1 T. Each of the four structural aluminium sites [Al(IV), Al(V)(1), Al(V)(2) and Al(VI)] are observed, characterised and assigned in the spectra. The obtained parameter set gives a fully consistent interpretation in agreement with the crystal structure of the compound.

Magnesium and Calcium Aluminate Liquids: In Situ High-Temperature 27Al NMR Spectroscopy.

The use of high-temperature nuclear magnetic resonance (NMR) spectroscopy provides a means of investigating the structure of refractory aluminate liquids at temperatures up to 2500 K. Time-averaged structural information indicates that the average aluminum coordination for magnesium aluminate (MgAl(2)O(4)) liquid is slightly greater than for calcium aluminate (CaAl(2)O(4)) liquid and that in both liquids it is close to four. Ion dynamics simulations for these liquids suggest the presence of four-, five-, and six-coordinated aluminate species, in agreement with NMR experiments on fast-quenched glasses. These species undergo rapid chemical exchange in the high-temperature liquids, which is evidenced by a single Lorentzian NMR line.

Neutralization and buffering capacity of leaves of sugar maple, largetooth aspen, paper birch and balsam fir.

We compared the acidity, the external acid neutralizing capacity and the buffering capacity of leaves of four commercially important tree species, largetooth aspen (Populus grandidentata Michx.), sugar maple (Acer saccharum Marsh.), paper birch (Betula papyrifera Marsh.) and balsam fir (Abies balsamea (L.) Mill), at two sites of contrasting soil fertility in southern Quebec. External acid neutralizing capacity (ENC) of leaves was determined by measuring the change in pH induced by soaking fresh leaves in an acidic solution (pH 4.0) for two hours. The ENC was highest for largetooth aspen (14.3 micro equiv H(+) g(-1)), and lowest for sugar maple and balsam fir (< 5 micro equiv H(+) g(-1)). The buffering capacity index (BCI) was determined by measuring the amount of acid necessary to produce a change of 5 micro equiv H(+) in the leaf homogenate. The BCI ranged from 883 micro equiv H(+) g(-1) for largetooth aspen to less than 105 micro equiv H(+) g(-1) for sugar maple and balsam fir. Leaves of sugar maple and balsam fir had a lower internal pH and a higher percentage of ENC over BCI than paper birch and largetooth aspen. Overall, ENC was correlated with the concentration of all leaf nutrients except Ca, and BCI was correlated with Mg, N and Ca. The site effect was relatively unimportant for all variables.

[Urticaria and antihistamines]. / L'urticaire et les anti-histaminiques.

Urticaria is often incapacitating, yet it is not always easy to know whether a patient should undergo testing and what treatment should be prescribed. This article provides a systematic approach to urticaria and its treatment.

Studies of the cyclic adenosine monophosphate chemoreceptor of Paramecium.

A doublet of proteins (approximately 48,000 Mr) from the Paramecium cell body membrane fits several criteria for the external cAMP chemoreceptor. These criteria include: (i) selective elution from a cAMP affinity column, matching a specificity that could be predicted from the behavioral response and whole-cell binding; (ii) binding to wheat germ agglutinin indicating the presence of carbohydrate moieties indicating surface exposure; and (iii) selective inhibition of the intact cells' chemoresponse to cAMP by antibodies against the doublet. Additional evidence for the existence of a receptor, in general, comes from selective elimination of the cAMP chemoresponse by photoaffinity labeling of while cells with 8-N3-cAMP. The doublet proteins are not identical to the regulatory subunit of a cAMP-dependent protein kinase from Paramecium, the Dictyostelium cAMP chemoreceptor, or the 42-45 kDa range proteins related to the large surface glycoprotein in Paramecium. The doublet proteins are not readily separable and, as in Dictyostelium, may represent two different covalent modification states of the same protein. Amino acid analysis indicates that the proteins are similar, but does not distinguish between the possibilities of proteolysis and covalent modification. Once cloned, this doublet may prove to be only the fifth external, eukaryotic chemoreceptor to be identified.

Autumnal changes of sulfur fractions and the ratio of organic sulfur to total nitrogen in leaves and adjacent bark of eastern cottonwood, white basswood and actinorhizal black alder.

Autumnal changes in organic-S, sulfate-S, total-S and the ratios of organic-S to total-N and sulfate-S to organic-S were followed in leaves and adjacent bark of actinorhizal (Frankia-nodulated) black alder (Alnus glutinosa (L.) Gaertn.) and eastern cottonwood (Populus deltoides Bartr. ex Marsh.) trees growing on a minespoil site high in extractable soil sulfate, and in black alder and white basswood (Tilia heterophylla Venten.) trees growing on a prairie-derived soil in Illinois. Organic-S concentrations decreased significantly (P < 0.05) during autumn only in foliage of trees growing on the prairie-derived soil where losses of leaf organic-S were 65% for black alder and 100% for white basswood. Leaf sulfate concentrations were relatively stable throughout autumn in white basswood growing on prairie-derived soil and in black alder at both sites. Sulfate-S concentrations in leaves were significantly (P < 0.05) higher in trees at the minespoil site than in trees growing in the prairie-derived soil (5.1 mg g(-1) for the minespoil site and 1.2 mg g(-1) for the prairie-derived soil), and in the non-actinorhizal species during late summer. During the autumn, the ratio of organic-S to total-N doubled in leaves of eastern cottonwood at the minespoil site, but in black alder and white basswood growing on the prarie-derived soil, it decreased by 60 and 74%, respectively. Organic-S concentrations in bark increased more during autumn in species unable to fix atmospheric N(2), than in black alder. The results suggest that patterns of autumnal translocation of leaf S can be site-dependent and that leaf S and leaf N are, at least in part, translocated independently in the fall. Black alder and eastern cottonwood seemed to incorporate sulfate-S readily into organic substances in leaves when grown in soils with a high sulfate content.

Leaf photosynthetic characteristics of seedlings of actinorhizal Alnus spp. and Elaeagnus spp.

Single leaf photosynthetic characteristics of Alnus glutinosa, A. incana, A. rubra, Elaeagnus angustifolia, and E. umbellata seedlings conditioned to ambient sunlight in a glasshouse were assessed. Light saturation occurred between 930 and 1400 µmol m(-2)s(-1) PAR for all species. Maximum rates of net photosynthesis (Pn) measured at 25°C ranged from 12.8 to 17.3 µmol CO2m(-2)s(-1) and rates of dark respiration ranged from 0.74 to 0.95 µmol CO2m(-2)s(-1). These values of leaf photosynthetic variables are typical of early to midsuccessional species. The rate of Pn measured at optimal temperature (20°C) and 530µmol m(-2)s(-1) PAR was significantly (p<0.01) correlated with leaf nitrogen concentration (r=0.69) and negatively correlated with the mean area of a leaf (r=-0.64). We suggest that the high leaf nitrogen concentration and rate of Pn observed for Elaeagnus umbellata and to a lesser degree for E. angustifolia are genetic adaptations related to their crown architecture.

Molecular mapping of the rosy locus in Drosophila melanogaster.

The DNA from the chromosomal region of the Drosophila rosy locus has been examined in 83 rosy mutant strains. Several spontaneous and radiation-induced alleles were associated with insertions and deletions, respectively. The lesions are clustered in a 4-kb region. Some of the alleles identified on the DNA map have been located on the genetic map by fine-structure recombination experiments. The genetic and molecular maps are collinear, and the alignment identifies the DNA location of the rosy control region. A rosy RNA of 4.5 kb has been identified; its 5' end lies in or near the control region.

Isolation and characterization of genomic mouse DNA clones containing sequences homologous to tRNAs and 5S rRNA.

We have cloned and characterized three fragments of Balb/c mouse DNA which hybridize to mouse cell tRNAs. Fractionation of the tRNAs which hybridize to these clones reveals that two of the clones, lambda Mt-4A and lambda Mt-6A hybridize to only one or two tRNAs, while one clone, lambda Mt-4B, hybridizes to at least seven tRNAs. Two of the tRNAs were identified as tRNAProCCG and tRNAGlyGGA, and others have been identified as tRNAs which are selectively encapsidated into virions of murine leukemia virus and avian reticuloendotheliosis virus. The DNA sequences of putative genes for tRNAProCCG and tRNAGlyGGA, plus flanking regions, were determined. A clone of Balb/c mouse DNA which selectively hybridized to 5S rRNA was also isolated and partially characterized.