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Biomedical subjects

J Moreau

Publications and source records attributed to J Moreau.

At least 145 records · Page 8Linked to original sources
PubMed1988

Genetic differences in response to pulmonary cytochrome P-450 inducers and oxygen toxicity.

The effects of cytochrome P-450 inducers on O2 toxicity were studied in mice. We first examined three cytochrome P-450 inducers, which differ by their specific tissue affinity: phenobarbital sodium (PB), essentially active in the liver, and 3-methylcholanthrene (3-MC) and beta-naphthoflavone (BNF), which are also active in the lung. Both BNF and 3-MC increased the survival rate and significantly decreased pulmonary edema (pulmonary water and wet-to-dry weight ratio) in C57BL/6J mice exposed to hyperoxia (O2 greater than or equal to 95%), whereas PB had no protective effect. In the second part of this study, we compared the action of BNF in two strains of mice. In one (C57BL/6J), cytochrome P-450 can be induced by aromatic hydrocarbons, whereas in the other (DBA/2J) cytochrome P-450 is not inducible by these compounds. Protection against O2 toxicity was assessed in terms of lethality and pulmonary edema and of lung lipid peroxidation (assessed by measuring malondialdehyde). BNF only protected against O2 toxicity in the inducible strain. This protective effect of BNF on O2 toxicity in C57BL/6J mice was associated mainly with a large increase in the components of the cytochrome P-450 system (cytochrome P-450 and cytochrome b5) in the lung. The activity of pulmonary superoxide dismutase was also slightly increased, but the enhancement was not statistically significant. In contrast, in DBA/2J mice neither the components of the cytochrome P-450 system nor the activity of superoxide dismutase showed any increase.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

[Complications of chickenpox seen in 44 patients in Abidjan].

The prevalence of complications is 38% in 116 patients with varicella. Cutaneous surinfection is observed in 30 patients (26%), pneumopathy in 4 cases resulting in death of 3 patients, encephalitis in 3 patients (1.7%). The authors discuss about those complications and their treatment.

Adolescent↗
PubMed1988

[Urinary steroids in calves following administration of anabolic compounds. Effect of total diet].

Levels of testosterone, trenbolone, 17 beta-estradiol (conjugated plus unconjugated) and creatinine were measured in urine of calves treated 55 days before with trenbolone and 17 beta-estradiol implants. The mean concentration of urinary creatinine and implant steroids was increased by a factor 3 after 1 day of total diet and 5 after 2 days, levels of individual calves exhibiting a great dispersion.

Animals↗
PubMed1988

[Comparison of fungal lipase and pancreatic lipase in exocrine pancreatic insufficiency in man. Study of their in vitro properties and intraduodenal bioavailability].

Assuming that acidic degradation of lipase was the major cause of failure for the correction of steatorrhea by pancreatic extracts, we compared the in vitro and in vivo activities of a fungal lipase (FL) (Rhizopus arrhizus) with classical porcine pancreatic extract (Eurobiol). The choice of FL was determined by its two optimum pH (3.5 and 7.4). Five factors known to modify lipase activity were tested: pH, biliary acids colipase, trypsin and albumin. Bioavailability was measured by using a double intubation method in 13 patients with severe pancreatic insufficiency. Each enzymatic preparation was given during a test meal in a randomized and cross-over fashion. Results of the in vitro study showed that FL differed from pancreatic lipase by the following properties: better resistance in acidic solution, inhibition by biliary salts, absence of effect of colipase and rapid degradation by trypsin. In vivo the percentage of lipase activity recovered was 14.2 +/- 10.6 p. 100 for FL and 56 +/- 50 p. 100 for the classical pancreatic preparation. Compared with placebo significant differences in the recovery rate of lipolytic activity were observed with the pancreatic preparation only and started at the 40th min after the end of the test meal. These results showed that lack of degradation in acidic milieu is not the only valuable criterion for the choice of an efficient lipase preparation. The role of other potential factors such as gastric emptying as well as proteolytic degradation of the enzyme should be considered as well.

Bile Acids and Salts↗
PubMed1987

Co-evolution of base composition and codon usage in Xenopus laevis and human globin genes with long-range DNA organization of their genome.

Eucaryotic DNA is punctuated by many A+T-rich segments that we named A+T-rich linkers. Two types of these A+T-rich linkers can be distinguished: (i) isolated A+T-rich linkers, and (ii) A+T-rich linkers crowded in clusters. We have analysed the distribution of A+T-rich linker across the alpha- and beta-globin gene domain in Xenopus laevis and human genomes using isodenaturation and electron microscopy. Comparison of our data with those previously obtained for the avian globin genes leads us to conclude that genes can be harboured indifferently in either domain. A correlation is established between the presence of A+T-rich linker inside introns and flanking regions and the A+T content of the coding sequence. For the coding sequence, a high A+T content is strongly correlated with high A+T content in the codon's third position and weakly in the first position.

Animals↗
PubMed1987

In vivo nitrogen dioxide exposure depresses spleen cell in vitro mitogenic responses: effects of sulfur compounds.

The in vivo mitogenic responses to lipopolysaccharide or concanavalin A by spleen cells of mice exposed to 20 ppm nitrogen dioxide (NO2) for 96 hr, were evaluated. [3H]Thymidine incorporation after addition of either mitogen, was significantly lower in spleen cells from acutely NO2-exposed mice (NO2 SC) than from control mice, although cell viability was not affected. T- and B-cell mitogenic responses were inhibited to the same extent by NO2 exposure. NO2 SC responses were protected by the thiol compounds 2-mercaptoethanol, L-cysteine, and selenomethionine. No restoration of mitogenic response was observed after treatment with reduced glutathione. Mechanisms accounting for this in vivo NO2 immune toxicity, are discussed in terms of oxidative injury.

Animals↗
PubMed1987

Evidence for humoral immunodepression in NO2-exposed mice: influence of food restriction and stress.

The effects of food restriction or 20 ppm NO2 exposure on humoral immunity were investigated in normal and adrenalectomized C57Bl/6 mice. The thymic and splenic weights of sham-operated mice were similarly diminished after 4 days of NO2 exposure or 4 days of food depletion. The responses of corresponding adrenalectomized mice were less depressed. Undernutrition induced lymphoid organ involution and corticosteroids were partly involved. Plaque-forming cells (PFC) per spleen and per 10(6) cells were markedly depressed after 4 days of NO2 exposure, but less so after food deprivation. The same significant suppression of PFC was observed in adrenalectomized groups. Depression of humoral immunity was independent of stress-induced endogenous steroids. Moreover, NO2 had a specific effect on humoral immunodepression, food restriction being an associated factor.

Animals↗
PubMed1986

Conservation and variation in the large scale organisation of the globin gene domains of duck and chicken.

The genomic DNA of cloned recombinants containing the duck globin genes was compared to that of the analogous domains of the chicken. A 36 kb insert including the three alpha-type globin genes was isolated from a newly prepared duck genomic library in the cosmid PJB8; another recombinant contained a 45 kb insert with the four beta globin genes. In the alpha globin gene domain, the relative positions of genes, of repetitive sequences, and of the A + T-rich segments (AT-rich linkers, ATRLs) which frame the gene cluster (Moreau et al. 1982), were found to be closely maintained between duck and chicken. Although ATRLs and repetitive sequences also frame the gene cluster in the beta globin domains of duck and chicken, there is more genetic drift in their relative positions than in the alpha domain. It is of interest that several repetitive DNA segments were detected in the chicken beta globin domain which do not exist in corresponding positions in the duck. In view of the strict conservation in both species of genes and their relative positions in the cluster, this observation seems to exclude a simple function of repetitive sequences in the control of individual genes. The data are discussed with regard to the possible significance of repetitive and AT-rich DNA segments in genome organisation and function.

Animals↗
PubMed1986

Correlations of repetitive and AT-rich DNA segments within the chicken globin gene domains.

The repetitive DNA segments were mapped within a 30 Kbp genomic domain including (in 5' to 3' order) the chicken embryonic pi and adult alpha D (minor) and alpha A (major) globin genes. Two repeats map 5 and 8 Kbp upstream from the embryonic pi gene and another 3 Kbp downstream of the adult alpha A gene. These repetitive DNA sequences are placed within, or immediately adjacent to the AT-rich DNA segments framing this domain. Similar correlations exist also within the chicken beta globin gene domain. The positions of these AT-rich and repetitive DNA segments framing the alpha globin gene domain also correlate with other already explored features of long range DNA organisation, as clusters of sites of DNAse I hypersensitivity and differential methylation, sites of Matrix-DNA attachment, and with the beginning and end of the transcribed domain.

Adenine↗
PubMed1985

Identification and molecular analysis of a multigene family encoding calliphorin, the major larval serum protein of Calliphora vicina.

A library of Calliphora vicina genomic DNA was constructed in the lambdaEMBL3 vector and screened for recombinant phages containing chromosomal segments encoding calliphorin, the major larval serum protein (LSP) of Calliphora. A large series of recombinants hybridizing with in vitro labelled poly(A) RNA from Calliphora larval fat bodies and with specific probes derived from the LSP-1 genes of Drosophila melanogaster was isolated. Five of these phages, chosen at random, were shown by hybrid selection to retain calliphorin mRNA specifically. Eleven calliphorin mRNA-homologous regions were located on restriction maps of these phages by hybridization with 5' end-labelled poly(A) RNA from Calliphora larval fat bodies. Each phage contains at least two calliphorin genes arranged in direct repeat orientation and seperated by 3.5-5 kb intergenic regions. The genes display similar but not identical restriction patterns. Filter hybridization and heteroduplex analysis indicate that they share a detectable homology with the LSP-1beta gene of D. melanogaster. Whole genome Southern analysis showed that these genes belong to a large family of closely related calliphorin genes which were found by in situ hybridization to polytene chromosomes of trichogen cells to be clustered in region 4a of chromosome 2 of Calliphora vicina.

Journal Article↗
PubMed1985

AT-rich linkers in long range organisation of Drosophila DNA.

AT-rich segments were mapped in 6 different domains of the Drosophila melanogaster genome by partial denaturation of cloned genomic DNA segments and observation in the electron microscope (EM). As found in a previous investigation (Moreau et al., 1982), three types of AT-rich segments could be distinguished: 1) AT-rich linkers with a very high AT content, 600 +/- 200 bp long; 2) clusters of such AT-linkers extending over up to 10 Kbp and 3) AT-rich stretches which are shorter and of lower AT content compared to AT-linkers. Six genes previously localized in these domains were found to lie in relatively GC-rich segments framed by AT-rich elements of the 3 types: the Larval Serum Protein LSP-1 alpha gene is framed by 2 AT-linkers, the LSP-1 beta and LSP-2 genes by two AT-rich stretches, an the LSP-1 gamma gene by a cluster and a stretch. The 55 Kbp genomic segment encompassing the P6 gene contains and AT-cluster of about 15 Kbp and several AT-linkers and AT-rich stretches. The 85 Kbp domain containing the P1 gene includes 3 AT-rich clusters of about 10 Kbp each framing GC-rich domains punctuated by AT-linkers and stretches. This study shows that AT-mapping allows a rapid diagnosis of large genomic DNA domains in relation to the AT-rich segments which, possibly, are of significance with regard to genome organisation and function.

Animals↗
PubMed1985

Application of learning techniques to splicing site recognition.

Most genes of eukaryotic genomes are disrupted by introns. The application of a learning technique which uses both statistic and syntactic analysis lead to the establishment of logical rules enabling the recognition of intron/exon junctions between uncoding and coding sequences. The rules were tested on rat actin gene sequences containing some or all of the introns and 50 exon nucleotides on either side of the intron. The results show good recognition of the excision site. This recognition is more ambiguous when the sequence is short; for the acceptor sequence it presents a good selection. The learning achieved with both the donor and acceptor sequence does not lead to recognition. This result indicates that it is not the relationship between donor and acceptor sites in the same intron which determines sequence selection or the splicing mechanism.

Base Sequence↗
PubMed1984

A complete and a truncated U1 snRNA gene of Drosophila melanogaster are found as inverted repeats at region 82E of the polytene chromosomes.

A phage containing two sequences homologous to U1 snRNA was isolated from a Drosophila melanogaster genomic library, and identified with a previously cloned D. melanogaster U1 snRNA gene. DNA sequence analysis showed that complete and truncated U1 snRNA genes are present, both of which have base substitutions relative to U1 snRNA. These genes show conservation of 5' and 3' flanking regions relative to other U1 and U2 snRNA genes of Drosophila. Intramolecular renaturation experiments and electron microscope mapping demonstrates that the two U1 snRNA sequences are present as inverted repeats about 2.7kb apart, separated by a smaller pair of inverted repeats of an unrelated sequence. These U1 snRNA sequences were located by in situ hybridization at 82E, and related sequences were found at 21D and 95C on the polytene chromosome map. The results are discussed with reference to the origin and function of snRNAs.

Animals↗
PubMed1984

Lung alterations in guinea-pigs infected with influenza virus.

Guinea-pigs were infected intranasally with influenza A Hong Kong 68 (H3N2) virus. Infective particles were re-isolated from lung homogenates up to 3 days after inoculation and indicated local replication. The subsequent lung inflammatory stages were studied by light microscopy, scanning and transmission electron microscopy (TEM). Lung alterations appeared after 24 h and intensified up to 7 days after virus inoculation, progressively decreasing until 3 weeks thereafter. The damage was reversible and complete restoration of structure was obtained within 5 weeks. The lesions commenced with the infiltration of bronchiolar and alveolar walls by polymorphonuclear cells, histiocytes and macrophages. A purulent exudate was seen to occupy the bronchiolar lumen. Cilia disappeared from tracheal and bronchiolar epithelia. Tracheal epithelium desquamated in some animals. TEM examination showed deterioration in type I pneumocytes, an increase in type II pneumocytes and concomitant damage to alveolar capillaries. Alveolar oedema and fibrinous deposits were seen. The pleura presented slight modifications. These results show that infection of guinea-pigs with influenza virus is a useful model for the study of lung pathology associated with a non-lethal respiratory viral infection.

Animals↗
PubMed1984

[24-hour duodenal pH-recording in chronic pancreatitis].

Decreased pancreatic bicarbonate secretion may be responsible for the low duodenal pH in chronic pancreatitis as compared to the normal. We have therefore performed a 24-hour continuous duodenal pH recording in 7 patients with chronic pancreatitis and in 7 controls. The comparison of results, expressed as the percent of the time with pH under 3, 4, 5 or 6, shows that in chronic pancreatitis, the duodenal pH was significantly lower than in normal subjects, particularly during the postprandial periods. The lower pH found in pancreatitis, causing an impairement of the catalytic activity of endogenous or exogenous pancreatic enzymes could both contribute to malabsorption and decrease the efficacy of substitutive pancreatic extracts.

Adult↗
PubMed1983

Pulmonary NO2 toxicity in neonate and adult guinea pigs and rats.

The pulmonary effects of NO2 were investigated in two animal species. Rats and guinea pigs aged from 5 to 60 days or more were exposed for 3 days either to 2 ppm or to 10 ppm NO2. Lung histology or superoxide dismutase (SOD) determination in alveolar macrophages was assessed in air and NO2-exposed animals. Results demonstrated that the lung histological alterations are different for both NO2-exposed species. Rats were more tolerant than guinea pigs, but rat and guinea pig newborns were less affected than adults. The enzyme response to NO2 exposure was similar in both species and a decrease in SOD activity was noted in animals of all ages. These observations support the conclusion that NO2 exposure leads to increased lung damage during the life span, but on the contrary, exposure to oxygen does not involve SOD induction. This suggests that the defense mechanisms against NO2 are different from those of O2.

Animals↗