The small hydrophobic (SH) gene of North American turkey AMPV-C does not attenuate nor modify host tropism in recombinant European duck AMPV-C.

Subgroup C Avian Metapneumoviruses (AMPV-C) has two lineages, one mostly in turkeys and one mostly in ducks. To investigate the molecular basis of AMPV-C host tropism, a reverse genetics system for a duck AMPV-C virus was developed. A recombinant copy and a recombinant virus in which the SH protein had been exchanged for that of a turkey AMPV-C were rescued. No change in cytopathogenic effect or replication profile in vitro were observed for either virus compared to the wild type. In SPF Muscovy ducks the wild type and its recombinant copy were equally pathogenic. Exchanging the SH in the recombinant copy produced the same results. In SPF turkeys, neither recombinant virus was pathogenic, although both showed a low level of replication. Thus, from the current model, it appears that AMPV-C SH proteins derived from the different species are compatible and that turkey SH does not affect duck AMPV-C pathogenicity.

Water-vapor isotope ratio measurements in air with a quantum-cascade laser spectrometer.

A spectrometer was used in the laboratory to study water-vapor isotope ratio measurements in air: H2 18O/H2 16O and HDO/H2 16O near 6.7 microm. The spectral region ranging from 1483 to 1487 cm(-1), which is suitable for the in situ laser sensing of major water-vapor isotopologues in the middle atmosphere from airborne or balloonborne platforms, was investigated by use of a continuous-wave distributed feedback quantum-cascade laser. The concentrations obtained were compared with the concentrations obtained with a hygrometer. The sigma(18O) values were found to be in excellent agreement with the standard value for two individual lines. The sigma(D) value was slightly higher than the standard value.

Inhibition of the expression and activity of cyclooxygenase-2 by chicory extract.

Chicory is a major source of fructans with reported prebiotic-bifidogenic properties. In the present study, the potential anti-inflammatory activities of chicory were investigated. Ethyl acetate chicory root extract produced a marked inhibition of prostaglandin E(2) (PGE(2)) production in human colon carcinoma HT29 cells treated with the pro-inflammatory agent TNF-alpha. Two independent mechanisms of action were identified: (1) a drastic inhibition of the induction by TNF-alpha of cyclooxygenase 2 (COX-2) protein expression and (2) a direct inhibition of COX enzyme activities with a significantly higher selectivity for COX-2 activity. The inhibition of TNF-alpha-dependent induction of COX-2 expression was mediated by an inhibition of NF-kappaB activation. A major sesquiterpene lactone of chicory root, the guaianolide 8-deoxylactucin, was identified as the key inhibitor of COX-2 protein expression present in chicory extract. Altogether, the data presented strongly support chicory root as a promising source of functional food ingredient, combining prebiotic and anti-inflammatory properties.

Preliminary results of heterodyne detection with quantum-cascade lasers in the 9 microm region.

In this paper, we describe recent results in mid-infrared heterodyne detection using quantum-cascade (QC) lasers as local oscillator (LO). In the 9 microm range, the heterodyne detection technique was first developed with CO(2) lasers and then with Pb-salt diode lasers. Quantum-cascade lasers are promising high quality tunable mid-infrared sources. We developed a quantum-cascade laser based heterodyne spectrometer. Atmospheric absorption spectra of ozone are presented.

Infrared laser heterodyne systems.

This paper gives a review of mid-infrared laser heterodyne systems. The advantages of using heterodyne detection are described and the different techniques corresponding to the choice of the local oscillator are presented. A thorough discussion of the gas laser heterodyne systems is followed by the presentation of tunable diode laser systems capabilities. Many experiments in the mid-infrared region are reviewed covering the astronomical and atmospheric, ground-based and airborne investigations as well as the laboratory measurements.

Free-running 9.1-microm distributed-feedback quantum cascade laser linewidth measurement by heterodyning with a C18O2 laser.

We report spectral linewidth measurements of a 9.1-microm distributed-feedback quantum cascade laser (QCL). The free-running QCL beam was mixed with a waveguide isotopic C18O2 laser onto a high-speed HgCdTe photomixer, and beat notes were recorded from a radio-frequency spectral analyzer. Beating was performed at two operating conditions, first near the QCL laser threshold (beating with the C18O2 R10 line) and then at a high injection current (beating with the C18O2 R8 line). Overall, beat note widths of 1.3-6.5 MHz were observed, which proves that a free-running QCL can have a short-term spectral width near 1 MHz.

Magnesium enrichment and distribution in plants.

Food products enriched with stable isotopes are used in nutrition to study the metabolic fate of nutrients in humans. This study reports on the labeling of green beans, white beans, soybeans and wheat with a stable isotope of magnesium (25Mg) obtained in greenhouse conditions for further studies on magnesium bioavailability. Soybean and green bean are the most efficient plant species to obtain large amounts of edible parts rapidly with a minimum loss of labeled Mg in other parts of the plants. The results obtained showed that a relatively high percentage of the magnesium found in seeds (grains/beans) can come from the redistribution of magnesium previously accumulated in other organs.

Optimisation of photoacoustic resonant cells with commercial microphones for diode laser gas detection.

The theoretical and experimental study of the differential Helmholtz resonant (DHR) cell sensitivity under variation of the total gas pressure is made for various commercial microphones. Near-infrared lasers (room-temperature diode lasers) were used to measure the response of DHR cell versus pressure of the absorbing gas and frequency of the laser radiation modulation. Several molecular absorbers like H2O, CH4, mixed with molecular buffer gases were used to investigate the behavior of the photoacoustic (PA) signal characteristics with a DHR cell. The experimental data are compared with the results of computer simulation. The minimal detectable concentrations of gases were determined for the DHR cell for each commercial microphone.

Free and protein-bound glutamine have identical splanchnic extraction in healthy human volunteers.

The objectives of the present study were to determine the splanchnic extraction of glutamine after ingestion of glutamine-rich protein ((15)N-labeled oat proteins) and to compare it with that of free glutamine and to determine de novo glutamine synthesis before and after glutamine consumption. Eight healthy adults were infused intravenously in the postabsorptive state with L-[1-(13)C]glutamine (3 micromol x kg(-1) x h(-1)) and L-[1-(13)C]lysine (1.5 micromol x kg(-1) x h(-1)) for 8 h. Four hours after the beginning of the infusion, subjects consumed (every 20 min) a liquid formula providing either 2.5 g of protein from (15)N-labeled oat proteins or a mixture of free amino acids that mimicked the oat-amino acid profile and contained L-[2,5-(15)N(2)]glutamine and L-[2-(15)N]lysine. Splanchnic extraction of glutamine reached 62.5 +/- 5.0% and 66.7 +/- 3.9% after administration of (15)N-labeled oat proteins and the mixture of free amino acids, respectively. Lysine splanchnic extraction was also not different (40.9 +/- 11.9% and 34.9 +/- 10.6% for (15)N-labeled oat proteins and free amino acids, respectively). The main conclusion of the present study is that glutamine is equally bioavailable when given enterally as a free amino acid and when protein bound. Therefore, and taking into consideration the drawbacks of free glutamine supplementation of ready-to-use formulas for enteral nutrition, protein sources naturally rich in this amino acid are the best option for providing stable glutamine.

Intestinal CD8 alpha alpha and CD8 alpha beta intraepithelial lymphocytes are thymus derived and exhibit subtle differences in TCR beta repertoires.

Intraepithelial lymphocytes (IEL) of the small intestine are anatomically positioned to be in the first line of cellular defense against enteric pathogens. Therefore, determining the origin of these cells has important implications for the mechanisms of T cell maturation and repertoire selection. Recent evidence suggests that murine CD8 alpha alpha intestinal IELs (iIELs) can mature and undergo selection in the absence of a thymus. We analyzed IEL origin by cell transfer, using two congenic chicken strains. Embryonic day 14 and adult thymocytes did not contain any detectable CD8 alpha alpha T cells. However, when TCR(+) thymocytes were injected into congenic animals, they migrated to the gut and developed into CD8alphaalpha iIELs, while TCR(-) T cell progenitors did not. The TCR V beta 1 repertoire of CD8 alpha alpha(+) TCR V beta 1(+) iIELs contained only part of the TCR V beta 1 repertoire of total iIELs, and it exhibited no new members compared with CD8(+) T cells in the thymus. This indicated that these T cells emigrated from the thymus at an early stage in their developmental process. In conclusion, we show that while CD8 alpha alpha iIELs originate in the thymus, T cells acquire the expression of CD8 alpha alpha homodimers in the gut microenvironment.

Production of ginkgolides and bilobalide by Ginkgo biloba plants and tissue cultures.

The accumulation of the terpenes ginkgolides and bilobalide in Ginkgo biloba was reported in plants as well as in plant cell cultures. Several hundred plants cultivated under controlled conditions in the field have been analyzed for their terpene production over many years. Cross-pollination experiments were performed with mature trees and the terpene content of the progeny was analyzed. The age of the tree is the main factor influencing the terpene content of the leaves as the level always decreases dramatically between young and old trees. 80 cell culture strains have been established and ginkgolides analyzed by GC/MS. These cell cultures reveal very low amounts of terpenes (1 microgram g-1 D.W. or less). On the contrary, isolated in vitro root cultures accumulate terpenes at the same concentration as the young plant leaves (4 mg g-1 D.W.). Attempts to obtain rapid growing roots or even hairy-roots did not succeed but the possibility to transform Ginkgo cell strains has been demonstrated.

Expression of a carrot invertase gene in tobacco suspension cells cultivated in batch and continuous culture conditions.

Plant cells (Nicotiana tabacum) were genetically modified to produce an heterologous protein, the acidic invertase from carrot, and invertase production from suspension tobacco cells was investigated. Suspension cultures were grown in shake flasks and stirred bioreactor. Total invertase activity was growth related. A 75 d continuous culture in 10 l bioreactor was performed. Our study demonstrates the high potential of plant cell cultures for long term production of heterologous protein.

Ontogeny of the immune system: gamma/delta and alpha/beta T cells migrate from thymus to the periphery in alternating waves.

The embryonic thymus is colonized by the influx of hemopoietic progenitors in waves. To characterize the T cell progeny of the initial colonization waves, we used intravenous adoptive transfer of bone marrow progenitors into congenic embryos. The experiments were performed in birds because intravenous cell infusions can be performed more efficiently in avian than in mammalian embryos. Progenitor cells, which entered the vascularized thymus via interlobular venules in the capsular region and capillaries located at the corticomedullary junction, homed to the outer cortex to begin thymocyte differentiation. The kinetics of differentiation and emigration of the T cell progeny were analyzed for the first three waves of progenitors. Each progenitor wave gave rise to gamma/delta T cells 3 d earlier than alpha/beta T cells. Although the flow of T cell migration from the thymus was uninterrupted, distinct colonization and differentiation kinetics defined three successive waves of gamma/delta and alpha/beta T cells that depart sequentially the thymus en route to the periphery. Each wave of precursors rearranged all three TCR Vgamma gene families, but displayed a variable repertoire. The data indicate a complex pattern of repertoire diversification by the progeny of founder thymocyte progenitors.

Characterization of avian T-cell receptor gamma genes.

In birds and mammals T cells develop along two discrete pathways characterized by expression of either the alpha beta or the gamma delta T-cell antigen receptors (TCRs). To gain further insight into the evolutionary significance of the gamma delta T-cell lineage, the present studies sought to define the chicken TCR gamma locus. A splenic cDNA library was screened with two polymerase chain reaction products obtained from genomic DNA using primers for highly conserved regions of TCR and immunoglobulin genes. This strategy yielded cDNA clones with characteristics of mammalian TCR gamma chains, including canonical residues considered important for proper folding and stability. Northern blot analysis with the TCR gamma cDNA probe revealed 1.9-kb transcripts in the thymus, spleen, and a gamma delta T-cell line, but not in B or alpha beta T-cell lines. Three multimember V gamma subfamilies, three J gamma gene segments, and a single constant region C gamma gene were identified in the avian TCR gamma locus. Members of each of the three V gamma subfamilies were found to undergo rearrangement in parallel during the first wave of thymocyte development. TCR gamma repertoire diversification was initiated on embryonic day 10 by an apparently random pattern of V-J gamma recombination, nuclease activity, and P-and N-nucleotide additions to generate a diverse repertoire of avian TCR gamma genes early in ontogeny.

Plant regeneration of Iris pallida Lam. and Iris germanica L. via somatic embryogenesis from leaves, apices and young flowers.

Irones are violet-scented ketonic compounds contained in the rhizome of certain species of iris. As cultivation of the iris tends to decrease, a selection program has been initiated to find the best performing clones in terms of growth and yield. Parallel to this selection, in vitro regeneration studies have been carried out in order to multiply interesting clones. A method of rapid multiplication by somatic embryogenesis associated with multibudding was developed. Callus was obtained from leaf bases, flower pieces or rhizome apices; the best explants were flower pieces. The induction media used to obtain embryogenic callus were Murashige & Skoog (1962) media. Assays with adding of proline in these media have showed that it could double the yield of embryogenic callus. The embryogenic expression medium was the Knudson's orchid agar (Knudson 1946) medium. Conformity of the plants obtained was checked by comparing their chemotypes with those of the mother plants.

[Cutaneous South-American Leishmaniasis. Parasitological and serological diagnosis by indirect immunofluorescence and enzyme linked immunoassay (ELISA). 94 cases]. / Leishmaniose cutanée sud-americaine. Diagnostic parasitologique et sérologique par immunofluorescence indirecte (IFI) et enzyme linked immuno assay (ELISA). A propos de 94 cas.

A parasitological (direct test and culture) and serological (IIF and ELISA) survey was carried out in 94 soldiers infested by a cutaneous South American leishmaniasis during a training in the guyanese forest. 52 p.c of the parasitological tests were positive, direct test being much more sensitive than cultures. By this technique, Leishmania Viannia guyanensis was detected 8 times, and Leishmania Viannia braziliensis twice. I.I.F. was negative in all cases because the utilization of a non-homologous antigen in the promastigote form and of the condition of its preparation. ELISA test utilizing the same antigen in a soluble form was specific and its sensitivity was 52 p.c. This technique was positive in 52 p.c of the cases, corroborating some diagnosis for which parasitological test was negative. 66 p.c of the total cases were confirmed.

[Focus on Schistosoma intercalatum]. / Le point sur Schistosoma intercalatum.

Area of frequent occurrence of Schistosoma intercalatum is limited to few countries along the Guinea Gulf although the main intervening agents, Bulinus globosus, Bulinus forskalii are dispersed all over Africa. Reservoir of Schistosoma intercalatum is only human and its cycle is difficult to keep up in test animals. Clinical manifestations are, the most often, a simultaneous inflammation of the rectum and sigmoid. Diagnosis is based on the presence of ova with terminal spine in feces or in biopsies of rectal mucosae. Serology, not specific of this species, eases finding of low infestations. Treatment is based on Praziquantel.

[Perforating folliculitis]. / La folliculite perforante.

We report the case of a 20-year old male patient without significant familial or personal history who presented with a disseminated papular eruption on the abdomen, flanks and buttocks. The eruption was continual and proceeded by outbreaks, but it was not influenced by seasons. Physical examination of the skin, mucosae and skin appendages was otherwise normal. Histological examination showed all the criteria of perforating folliculitis as described by Mehregan and Coskey. On the basis of our case we would put perforating folliculitis back among the perforating dermatoses. The concept of this curious phenomenon is briefly reviewed; perforating folliculitis is part of the third group of the so-called primary forms. The clinical features are suggestive of the disease, with its small pigmented papules centred around a keratotic plug, forming a permanent disseminated eruption. Histology shows a granuloma facing a lateral perforation of the hair follicle, a pseudo-epitheliomatous epithelial hyperplasia and the presence of hair and keratin debris in the perforation. Various keratolytic treatments have been applied without success; retinoids have not been tried. The main diagnostic and nosological problem is Kyrle's disease. In view of clinical and histological data, many authors regard Kyrle's disease as a major form of perforating folliculitis. Pruritus, ascribed to an underlying illness in Kyrle's disease, is thought to increase the importance of the lesions. The specificity of perforating folliculitis is discussed, but it seems that side by side with secondary forms occurring in recognized diseases, there may be primary forms of perforating folliculitis. Dyskeratosis might be a cause of the perforation.

[Diagnostic difficulties and current clinical aspects of Plasmodium falciparum malaria upon returning from a chemoresistance area]. / Difficultés diagnostiques et aspects cliniques actuels du paludisme à Plasmodium falciparum au retour d'une zone de chimiorésistance.

The incidence and clinical aspects of malaria in patients returning from chemoresistance areas were evaluated by means of two studies. The first one was a prospective study of 145 subjects back from a 4 months' stay in Gabon and who had complied with an appropriate chemoprophylaxis regimen. Twelve of these subjects were found to have particulate P. falciparum antigens on the 3rd day following their return. Spontaneous negativation of parasitaemia was observed in 10 cases, whereas 2 subjects were about to develop a malarial attack. Forty-five days after the return home, 5 new cases of malarial attack and 3 cases of anaemia had occurred, although none of these 8 patients had haematozoa on the 3rd day. In the second study 31 patients admitted to hospital in 1987 were reviewed. The following clinical syndromes were detected: malarial attacks with high parasitaemia in 6 cases, malarial attacks with low or undetectable parasitaemia in 5 cases, anaemia, thrombocytopenia or pancytopenia in 5 cases, and febrile alteration of the general condition in 3 cases. Two aspects of malaria were identified: "malaria infection" with a latent and asymptomatic parasitic infestation likely to disappear spontaneously or to turn into "malaria disease". The latter has protean manifestations, but bouts of fever with low parasitaemia and blood disorders are predominant.