études sur les phénomenes électrocapillaires

Sans résuméI. Analyse électrocapillaire des matières colorantes. Rev. gén. Mat. Col. 1926 Vol. 30 pp 34–45II. Phénomènes électrocapillaires et le problème du cancer. Arch. Med. Exper. 1926 Vol. I p 381III. Phénomènes électrocapillaires et l'antagonismes microbiens. Bol. Istituto Sier. Milano 1927 Vol. VI p 313.     

Isolation from Pasteurella multocida of a Lipopolysaccharide Antigen with Immunizing and Toxic Properties

A heat-stable, particulate, lipopolysaccharide-protein antigenic complex has been isolated from a virulent, encapsulated strain of Pasteurella multocida by extraction with cold, formalinized saline, and centrifugation at 105,000 x g. The original bacterial culture had been obtained from a bison that died of hemorrhagic septicemia, an infectious disease of cattle and buffalo. Injection of fractional milligram amounts of the antigen into mice, rabbits, and calves produced toxic reactions which frequently resulted in death of the host. The surviving animals demonstrated a high degree of immunity to challenge with live, virulent organisms. Two injections with 15 mug of the antigen produced a high degree of immunity in mice without the development of any signs of toxicity. The gross chemical composition and toxicity of the antigen were similar to those reported for endotoxins obtained by the Boivin or Westphal procedure. Although strong serological cross-reactions were obtained in Ouchterlony plates between the 105,000 x g antigens from the bison strain and an avian strain with antisera to these strains, these antisera agglutinated only the bacterial cells of the homologous strain. The active immunity obtained in mice by the injection of the 105,000 x g antigens of each strain was specific and could be correlated with the agglutination tests.     

Analysis of higher-primate phylogeny from transversion differences in nuclear and mitochondrial DNA by Lake's methods of evolutionary parsimony and operator metrics

In the companion paper (Holmquist et al. 1988), we concluded that there is no agreement on either the correct branching order or differential rates of evolution among the higher primates, and we examined in depth why this uncertainty in the evolutionary understanding of our closest living relatives persists. Recently, Lake developed two novel methods, based on group properties of transition and transversion operators, that (a) permit, in principle, objective resolution of problems of the above type and (b) attach a statistical significance level to the conclusions drawn. In the present paper, we develop formulas for using these two methods in tandem and apply them to study transversion differences in (1) nuclear DNA for a 7-kb segment of the psi eta-globin locus and a 3-kb intergenic region between the psi beta- and delta- globin loci and (2) mitochondrial DNA for the 896-bp fragment of Brown et al. Although each of these nucleotide sequence regions has its characteristic tempo and mode of evolution, the nuclear and mitochondrial data together, comprising a total of 10,939 base positions, support a Homo/Pan clade at the 97% confidence level. If we calibrate the divergence point for humans and chimpanzees at 5 Myr, consideration of the transversion branch lengths for the combined nuclear data indicates that the gorilla lineage branched off 600,000- 900,000 years prior to that, although the 2 sigma sampling errors do not preclude either a temporal trifurcation for the three species or a considerably more ancient branch point for the gorilla. To resolve the length of this central branch to a relative accuracy of 25% and 30% will require a factor of 16 and nine times more data, respectively-- i.e., in excess of 100,000 homologous nucleotides for each of the four primates. For the nuclear genes, heterogeneity in evolutionary rates between different parts of the genome is mostly restricted to the human lineage for these two segments. The lineage leading to chimpanzees has evolved 0.4 (3-kb fragment) to 3.5 (7-kb segment) times as rapidly as the lineage leading to humans, and that leading to the gorilla has evolved approximately one-fifth to one-half as rapidly as that leading to chimpanzees. Thus, even local molecular clocks can "tick" badly. As significant is the fact that virtually contiguous parts of the genome tick at markedly different rates.(ABSTRACT TRUNCATED AT 400 WORDS)      

Reactive oxygen-mediated contraction in pulmonary arterial smooth muscle: cellular mechanisms.

Reactive oxygen species (at least relatively high doses) cause contraction of pulmonary arterial smooth muscle. The objective of the present study was to elucidate the possible cellular mechanisms involved in reactive oxygen-mediated contraction. Isolated arterial rings from Sprague-Dawley rats were placed in tissue baths containing Earle's balanced salt solution. The maximum active force production (Po) in response to 80 mM KCl was obtained. All other responses were normalized as percentages of Po for comparative purposes. Exposure to reactive oxygen (generated from either the xanthine oxidase reaction (XO) or the glucose oxidase reaction) resulted in pulmonary arterial muscle developing mean active tension of 17.1 +/- 3.0% Po. This contraction was independent of extracellular calcium, since it was not affected by verapamil (a calcium channel blocker) or by placement of the arterial muscle in calcium-free media. Phentolamine (an alpha 1-receptor blocker) and propranolol (a beta-receptor blocker) did not diminish the response to XO. Ryanodine (a SR calcium release inhibitor), while reducing the response to norepinephrine, did not affect the response to XO. However, H-7 (an inhibitor of protein kinase C) decreased the XO-mediated contraction by 49%. These results indicate that while Ca2+ may not be involved as a second messenger, protein kinase C activity appears to play a role in the transduction pathway of reactive oxygen species mediated contraction of pulmonary arterial smooth muscle.     

Meta-analysis of the literature on diagnostic accuracy of SPECT in parkinsonian syndromes

Background  

Parkinson's disease (PD) is the second most common neurodegenerative disorder. One of the most widely used techniques to diagnose PD is a Single Photon Emission Computer Tomography (SPECT) scan to visualise the integrity of the dopaminergic pathways in the brain. Despite this there remains some discussion on the value of SPECT in the differential diagnosis of PD. We did a meta-analysis of all the existing literature on the diagnostic accuracy of both pre- and post-synaptic SPECT imaging in the differential diagnosis of PD.     

Non-Human Primates Harbor Diverse Mammalian and Avian Astroviruses Including Those Associated with Human Infections

Astroviruses (AstVs) are positive sense, single-stranded RNA viruses transmitted to a wide range of hosts via the fecal-oral route. The number of AstV-infected animal hosts has rapidly expanded in recent years with many more likely to be discovered because of the advances in viral surveillance and next generation sequencing. Yet no study to date has identified human AstV genotypes in animals, although diverse AstV genotypes similar to animal-origin viruses have been found in children with diarrhea and in one instance of encephalitis. Here we provide important new evidence that non-human primates (NHP) can harbor a wide variety of mammalian and avian AstV genotypes, including those only associated with human infection. Serological analyses confirmed that >25% of the NHP tested had antibodies to human AstVs. Further, we identified a recombinant AstV with parental relationships to known human AstVs. Phylogenetic analysis suggests AstVs in NHP are on average evolutionarily much closer to AstVs from other animals than are AstVs from bats, a frequently proposed reservoir. Our studies not only demonstrate that human astroviruses can be detected in NHP but also suggest that NHP are unique in their ability to support diverse AstV genotypes, further challenging the paradigm that astrovirus infection is species-specific.     

Methane oxidation coupled to oxygenic photosynthesis in anoxic waters

Freshwater lakes represent large methane sources that, in contrast to the Ocean, significantly contribute to non-anthropogenic methane emissions to the atmosphere. Particularly mixed lakes are major methane emitters, while permanently and seasonally stratified lakes with anoxic bottom waters are often characterized by strongly reduced methane emissions. The causes for this reduced methane flux from anoxic lake waters are not fully understood. Here we identified the microorganisms and processes responsible for the near complete consumption of methane in the anoxic waters of a permanently stratified lake, Lago di Cadagno. Interestingly, known anaerobic methanotrophs could not be detected in these waters. Instead, we found abundant gamma-proteobacterial aerobic methane-oxidizing bacteria active in the anoxic waters. In vitro incubations revealed that, among all the tested potential electron acceptors, only the addition of oxygen enhanced the rates of methane oxidation. An equally pronounced stimulation was also observed when the anoxic water samples were incubated in the light. Our combined results from molecular, biogeochemical and single-cell analyses indicate that methane removal at the anoxic chemocline of Lago di Cadagno is due to true aerobic oxidation of methane fuelled by in situ oxygen production by photosynthetic algae. A similar mechanism could be active in seasonally stratified lakes and marine basins such as the Black Sea, where light penetrates to the anoxic chemocline. Given the widespread occurrence of seasonally stratified anoxic lakes, aerobic methane oxidation coupled to oxygenic photosynthesis might have an important but so far neglected role in methane emissions from lakes.