Benefits of a rapid HIV test for evaluation of the source patient after occupational exposure of healthcare workers.

Rapid human immunodeficiency virus (HIV) testing for the management of occupational exposure of healthcare workers significantly decreased the number of anti-retroviral post-exposure prophylaxis regimens started whilst awaiting HIV test results. The study confirmed an equivalent performance of the rapid test in comparison with HIV enzyme immunoassay, and suggests it is cost-effective. In addition, two other potential benefits emerged: reducing the number of source patients who remain untested and increasing the number of occupational exposures reported.

[Occupational asthma in a teacher after repeated exposure to tear gas]. / Asthme professionnel chez une enseignante après inhalation répétée de gaz lacrymogènes.

Acute exposure to tear gas causes generally reversible cutaneous and mucosal irritations. Lasting respiratory manifestations after exposure are exceptional. We report the case of a 26-year-old female teacher with no history of respiratory disease who developed asthma after repeated exposure to tear gas discharged in her class room. The disorders occurring during these repeated exposures to the irritating gas were consistent with the recently described low level reactive airway dysfunction syndrome (low level RADS).

Nuclear estrogen binding sites in the liver of the newt Pleurodeles waltl.

Previous investigations of the liver estrogen-specific binding in the newt, Pleurodeles waltl, have identified in the cytosol fraction, only from normal males, a new middle-affinity estrogen-binding component (MEBC) displaying the properties of type II sites reported in various tissues of vertebrates. The present work demonstrates that MEBC sites are not unique to the male but are also present in the nuclei of female animals. However, comparative study between males and females of liver nuclear sites under various extraction conditions shows sex-linked differences in the subnuclear localization. The relationships between the association states of MEBC in the nuclear compartment according to sex and their presence or absence in the cytosol fraction are discussed.

Hormonal influences on the middle-affinity estrogen-binding sites in the liver of the newt Pleurodeles waltl.

The effects of hormonal changes on the male-specific, middle-affinity, estrogen-binding component (MEBC) were investigated in the Pleurodele. Induction of MEBC was shown to be under androgen control, similar to that observed for the cytoplasmic middle-affinity estrogen-binding sites in rat liver and human hepatoma cells. But, in contrast to the male-specific middle-affinity estrogen-binding sites identified in the rat, the administration of estrogen to male Pleurodeles did not lead to the disappearance of MEBC but raised levels significantly. The MEBC displays the properties of type II middle-affinity estrogen-binding sites, which are characterized by an oestrogen-dependent rise, a sensitivity to reducing agents, a specificity for diethylstilbestrol, and a binding capacity enhanced by increasing dilutions of cytosol. In female Pleurodeles, MEBC can be induced by treatment with androgens. This induction appears to be modulated by the estrogen/androgen ratio. The induction of MEBC and the estrogen-dependent increase in the male were not found to be correlated with hepatocyte proliferation.

A new micronucleus test using peripheral blood erythrocytes of the newt Pleurodeles waltl to detect mutagens in fresh-water pollution.

A model micronucleus test system using peripheral blood erythrocytes from larvae of Pleurodeles waltl is described. The most suitable larval stage for testing chemical treatments was determined. Larvae were reared in water containing one of the 4 compounds: benzo[a]pyrene (BaP), ethyl methanesulphonate (EMS), diethyl sulphate (DES) and N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG). Response curves as a function of treatment duration over a period of 16 days were plotted for 3 different concentrations of the 4 compounds in order to optimize conditions for a low dose micronucleus test. This model can be used as a monitoring system for the detection of fresh water pollution and can also be employed for clastogen screening of chemical compounds. The test is sensitive, reliable and easy to use.

Induction of micronuclei in peripheral erythrocytes of axolotl larvae following in vivo exposure to mutagenic agents.

Previous work from this laboratory demonstrated the presence of micronuclei in erythrocytes from larvae of the urodele amphibian Pleurodeles waltl reared in water containing clastogenic substances. In order to investigate the generality of this finding, larvae from another urodele Ambystoma mexicanum (axolotl) were reared in water containing one of the two following compounds: benzo[a]pyrene (BaP) or ethylmethane sulphonate (EMS). The level of micronucleated erythrocytes on blood smears was compared with control samples from larvae reared in fresh water. The optimum larval stage for this test system was determined. The effects of the indirect mutagen (BaP), and the direct mutagen (EMS) were found to depend on both dose and exposure to the clastogen. Positive results were obtained for BaP after 8 days of treatment at a concentration of 0.025 p.p.m. After 10 days of treatment at a concentration of 0.1 p.p.m. numerous micronuclei were seen (greater than 250%). Positive results were also obtained with EMS after 8 days of treatment at a concentration of 24 p.p.m. At 62 p.p.m., positive results were found after 6 days of treatment, while at 124 p.p.m. positive results were found after only 4 days. The results with both these agents show that the axolotl holds promise as an in vivo test system for the detection of low concentrations of clastogens in an aquatic environment.

Identification of the vitellogenin proteins in the newt Pleurodeles waltl (urodele amphibian).

Vitellogenin derived from the blood of estrogen-treated Pleurodeles waltl was identified by immunochemical and electrophoretic analyses, using an antiserum against plasma vitellogenin isolated by dimethylformamide precipitation. Pleurodeles vitellogenin migrates as four bands on native PAGE, designated alpha-, beta-, gamma- and delta- VTG, with apparent mol. wts of 250,000, 270,000, 280,000 and 520,000 respectively. In the plasma, from estrogen-treated males like from ovariectomized estrogen-treated females, an additional band (mu-VTG) was found by native PAGE, never observed in estrogen-treated female plasma. It has a mol. wt of about 380,000 and shows complete immunological cross-reactivity with the vitellogenin antiserum. At least two polypeptides, termed VTG-I and VTG-II (mol. wt = 180,000 and 210,000) were identified by SDS-PAGE. Rocket immunoelectrophoresis displays three distinct precipitate lines indicating major immunological differences between the plasma vitellogenins.

Micronuclei in red blood cells of the newt Pleurodeles waltl after treatment with benzo(a)pyrene: dependence on dose, length of exposure, posttreatment time, and uptake of the drug.

Aquatic larvae of the newt Pleurodeles waltl were exposed to different concentrations of benzo(a)pyrene (BaP) for various lengths of time. Frequencies of micronuclei in circulating erythrocytes were determined at different times after termination of the treatment. The incidence of micronuclei in larvae kept for 8 days in BaP-containing water displayed a marked increase with dose up to 0.075 ppm and a more gradual one with higher doses, reaching 158 per 1,000 at 0.75 ppm. The lowest dose at which a significant increase could be discerned was 0.01 ppm. Short periods of exposure, less than 2 days, did not result in a marked increase in micronuclei. Uptake and release was studied with tritiated BaP. Larvae concentrated BaP rapidly, attaining maximal levels after 12 hr. The ratio of radioactivity in larvae to that in an equivalent volume of surrounding water was about 200 independent of the amount of BaP added. Calf serum or bovine serum albumin added to the water lowered this ratio by competing for binding to BaP. Radioactive larvae placed in regularly renewed noncontaminated water lost 99% of the label after 100 hr. It is concluded that pleurodele larvae are a promising model for the detection of genotoxic activity in the aquatic environment.

Comparative plasma levels of androgens and 17 beta-estradiol in the diploid and triploid newt, Pleurodeles waltl.

Seasonal changes in the plasma levels of androgens (testosterone plus dihydrotestosterone) and 17 beta-estradiol in diploid and triploid adult newts, Pleurodeles waltl were studied. In both male and female diploid individuals, large variations were reported with highest levels being found during breeding periods. In triploid newts seasonal variations were also found, similar to the diploid ones, but the plasma concentrations of the 17 beta-estradiol and androgens in triploid females and androgens in triploid males were lower throughout the year than those reported for the diploids. This difference is discussed in relation to the genetic sexual constitution.

Globin gene expression in erythroid cell lines during larval development of Pleurodeles waltlii.

We have attempted to determine whether in Pleurodeles ontogenesis there exists a close relationship between the two following characteristics: change from primitive to definitive erythroid cell populations, which parallels the change of major erythropoietic site; change in the type of synthesized hemoglobin, larval or adult. The origin of red blood cells was investigated by embryonic grafts of hemopoietic anlage from 2n to 4n embryos. The larval or adult hemoglobin type was characterized by immunofluorescence by using specific antibodies. Our results show that in Pleurodeles, blood island-originating red blood cells and spleen-originating red blood cells are both able to synthesize either Hb L or Hb A at a given time, but in separate cells.

The role of endoderm in blood cell ontogeny in the newt Pleurodeles waltl.

In order to determine the origin of blood cells we performed embryonic grafts of different portions of mesoderm from various locations between diploid and tetraploid embryos at the tail-bud stage. The tetraploid animals were the hosts. The size differences between tetraploid and diploid cells made identification possible by direct microscopic examination of blood smears. In a previous report we showed the important role of truncal anterior mesoderm in the genesis of blood cells. We now establish that this effect is brought about by the inductive capacity of the hepatic endoderm or by the fact that the environmental conditions are more appropriate for blood stem cell development, whereas in the absence of the hepatic endoderm the blood stem cells fail to appear. Grafting of hepatic anlage containing endoderm and mesoderm gives rise to numerous graft-derived blood cells which last throughout the life span of the hosts. The same result is obtained by grafting truncal posterior ventral or lateral mesoderm onto hepatic endoderm. Heterotopic grafting of truncal anterior mesoderm isolated from its underlying hepatic endoderm leads to the formation of only a few blood cells which last only during larval life. This demonstrates that the whole lateral and ventral truncal mesoderm is able to differentiate into blood cells when associated with hepatic endoderm.

Micronuclei in red blood cells of the newt Pleurodeles waltl Michah: induction with X-rays and chemicals.

Pleurodeles waltl, a typical long-tailed amphibian (Urodela) is proposed as a new animal for genetic toxicological studies. X-Rays and various clastogenic substances cause the formation of clearly visible micronuclei in the red blood cells (RBC). The proportion of cells with micronuclei was determined from blood smears of larvae after irradiation or after having been kept in water containing the substances to be studied. A dose-effect curve was established for X-irradiation. The 6 following substances were tested by this method: benzo[alpha]pyrene, carbaryl, N-nitrosocarbaryl, aziridine, caffeine and formaldehyde. Formaldehyde was the only substance tested that did not bring about formation of micronuclei in the RBCs. The results were compared with data already obtained by other methods of toxicology. This method should allow a cytogenetic test to be developed for the detection of clastogenic substances in aqueous media.

A genetic study of various enzyme polymorphisms in Pleurodeles waltlii (Urodele amphibian). I. Lactate dehydrogenase-B and glucose-6-phosphate dehydrogenase.

On starch gel electrophoresis of erythrocyte hemolysates of Pleurodeles waltlii (Urodele Amphibian), both lactate dehydrogenase-B (LDH-B) and glucose-6-phosphate dehydrogenase (G6PDH) show polymorphism that depends on a pair of autosomal codominant alleles, confirmed by analysis of gynogenesis progeny. Diploid gynogenesis results from fusion of the female pronucleus with the second polar body. The heterozygous state of a female for a given character is maintained in certain progeny when crossing-over occurs between the locus in question and the centromere. So the high proportion of heterozygotes (45.7% for LDH-B and 76% for G6PDH) indicates the high frequency of crossing-over and hence the large distance between each of the loci and the centromere.

Hemoglobin switching in the salamanderPleurodeles waltlii : Immunofluorescence detection of larval and adult hemoglobins in single erythrocytes.

In order to study the cellular distribution of larval and adult hemoglobins during larval development ofPleurodeles waltlii a double specific immunofluorescent labelling technique was developed.Rabbit antibodies specific for larval and adult hemoglobin components were prepared and conjugated with tetramethyl-rhodamine isothiocyanate for the anti-larval antibodies and fluorescein isothiocyanate for the anti-adult hemoglobin antibodies.Both simultaneous and sequential staining with the two types of fluorescent antibodies indicated that larval and adult hemoglobins were never observed within the same erythrocyte during development. The results provide evidence that two distinct cell populations exist, one synthesizing exclusively larval hemoglobins which is progressively replaced by the other one synthesizing exclusively adult hemoglobins. It remains to be determined if these two populations arise from two distinct types of stem cells (adult and larval) or from the same stem cell type.

Thymic lymphocyte origin in the newt Pleurodeles waltlii studied by embryonic grafts between diploid and tetraploid embryos.

Thymic lymphocytes origin in the newt Pleurodeles waltlii was studied by embryonic grafts of the gill area between diploid and tetraploid embryos. By this way, either cell size or chromosome number are used as markers. Heterotopic transplantation of the gill area to the ventral region of a host embryo is followed by differentiation of gills and gill-associated structures including thymus. Analysis of cell size and chromosome number shows that in Pleurodeles, thymocytes do not differentiate in situ but originate from blood-borne stem cells that migrate into the thymus anlage.

Erythrocyte enzyme activities in diploid and triploid salamanders (Pleurodeles waltlii) of both sexes.

Studies of several enzyme activities and of some metabolites in erythrocytes of the newt Pleurodels waltilii are described. The results indicate that differences exist between enzyme activities in males and females and in diploid and triploid animals. Females have higher erythrocyte enzyme activities than males. However, triploid animals have lower enzyme activites in their erythrocytes than diploid animals; this observation is more striking in females than in males.

[Studies on the origin of various blood cell lines in the salamander Pleurodeles waltlii (author's transl)]. / Recherches sur l'origine des différentes lignées de cellules sanguines chez l'amphibien urodèle Pleurodeles waltlii

Grafting of haemopoietic organs was performed at several developmental stages between diploid and autotetraploid individuals of Pleurodeles waltlii. The difference in size between diploid and tetraploid cells is so obvious that their identification is possible by direct microscopic examination. To avoid immunological rejection, the grafts have been made with inbred animals. 2. After grafting the spleen, the host cells are observed to colonize it. This phenomenon is more important with spleens from donors at early stages of development. When the spleen from a late larval stage or a metamorphosed animal is transplanted into another larva, the blood of the latter contains 66 or 72% erythrocytes originating from the graft. 3. Embryonic liver grafting is followed by a colonization of all haemopoietic organs by cells originating from the granulopoietic tissue of the graft. The proportion of grafted blood cells is then very high. A liver graft performed at a larval stage gives qualitatively similar results but the numbers of cells originating from the graft are lower. A survey of intra-cardiac erythropoiesis in these animals shows that it develops from stream blood cells and not from cardiac endothelial cells. 4. After thymus graft, the lymphoid part of the organ is replaced by the host cells. 5. From these results, it is suggested that the granulopoietic liver tissue contains one or several kinds of stem cells which could differentiate into all types of blood cells.