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Biomedical subjects

C Louis

Publications and source records attributed to C Louis.

At least 91 records · Page 5Linked to original sources
PubMed1991

Esophageal atresia, tracheomalacia and arterial compression: role of aortopexy.

Between 1985 and 1990, we treated 46 cases of esophageal atresia in the pediatric surgery department in Marseille. In 17 of these patients atresia was associated with tracheomalacia. The most common respiratory manifestations were acute apneic attacks, cyanotic spells and recurring pneumopathy. The underlying cause was arterial compression of the airways by the innominate artery in 6 cases, the aortic arch in 2 cases, and a common origin of the innominate and left carotid arteries in 2 cases. Eleven patients underwent surgery to relieve arterial compression: suspension of the aorta from the under surface of the sternum (10 cases) and reimplantation of the innominate artery (1 case). Results in terms of tracheal caliber and symptomatic relief were excellent in 10 cases including 1 case requiring redo, and poor in 1 case. For diagnosis, our experience shows the importance of endoscopy, nuclear magnetic resonance and recognition of gastroesophageal reflux which is often associated (9/11). The role of tracheomalacia is discussed. On the basis of our results and those previously reported, aortopexy appears to be an effective surgical technique in patients with esophageal atresia presenting respiratory complications due to arterial compression.

Airway Obstruction↗
PubMed1991

Observer disagreement in rating neurologic impairment in multiple sclerosis: facts and consequences.

The interobserver variability of the expanded disability status scale (EDSS) was studied in 59 patients with multiple sclerosis (MS). Interrater agreement was measured by the kappa coefficient. Agreement was low in patients with mild disability (EDSS less than 5); it was higher in patients with EDSS equal to or greater than 5. The difference between ratings of 2 independent examiners was equal to at least 1 point in 34% of the MS cases. This variability must be taken into consideration in designing clinical trials in MS.

Adult↗
PubMed1990

Towards a physical map of the Drosophila melanogaster genome: mapping of cosmid clones within defined genomic divisions.

A physical map of the D. melanogaster genome is being constructed, in the form of overlapping cosmid clones that are assigned to specific polytene chromosome sites. A master library of ca. 20,000 cosmids is screened with probes that correspond to numbered chromosomal divisions (ca. 1% of the genome); these probes are prepared by microdissection and PCR-amplification of individual chromosomes. The 120 to 250 cosmids selected by each probe are fingerprinted by Hinfl digestion and gel electrophoresis, and overlaps are detected by computer analysis of the fingerprints, permitting us to assemble sets of contiguous clones (contigs). Selected cosmids, both from contigs and unattached, are then localized by in situ hybridization to polytene chromosomes. Crosshybridization analysis using end probes links some contigs, and hybridization to previously cloned genes relates the physical to the genetic map. This approach has been used to construct a physical map of the 3.8 megabase DNA in the three distal divisions of the x chromosome. The map is represented by 181 canonical cosmids, of which 108 clones in contigs and 32 unattached clones have been mapped individually by in situ hybridization to chromosomes. Our current database of in situ hybridization results also includes the beginning of a physical map for the rest of the genome: 162 cosmids have been assigned by in situ hybridization to 129 chromosomal subdivisions elsewhere in the genome, representing 5 to 6 megabases of additional mapped DNA.

Animals↗
PubMed1990

The gene coding for glutamate dehydrogenase in Drosophila melanogaster.

We have isolated the Drosophila melanogaster locus coding for L-glutamate dehydrogenase (EC 1.4.1.3) by virtue of its similarity to the corresponding human gene. There is only one copy of this gene in the fruit fly genome, located on the right arm of chromosome 3 (95D1-4). The transcript includes at least one large intron and matures to a approximately 2.4-kb-long polyadenylated RNA whose expression is under developmental control.

Animals↗
PubMed1989

PCR amplification of DNA microdissected from a single polytene chromosome band: a comparison with conventional microcloning.

A novel alternative to microcloning for the production of region specific chromosomal DNA is described. In this method, 'microamplification', single bands are dissected from polytene chromosomes and digested with Sau3A. Oligonucleotide adaptors are ligated to these fragments to provide convenient priming sites for polymerase chain reaction amplification. In this way, as much as 1 microgram of DNA can be amplified from a single band. Probes made from PCR amplified DNA from two such dissections have been used to probe cloned DNA form a 100 kb chromosome walk. Whereas conventional microcloning has generated cloned EcoRI fragments corresponding to 3-4 kb of the walk, the PCR probes cover greater than 90% of this chromosomal region. Thus microamplification is significantly more effective than microcloning in providing probes for establishing chromosomal walks.

Animals↗
PubMed1989

The P-M and the 23.5 MRF (hobo) systems of hybrid dysgenesis in Drosophila melanogaster are independent of each other.

Strains of Drosophila melanogaster bearing the male recombination factor 23.5 MRF induce hybrid dysgenesis in a way which is highly reminiscent of the P-M system, and, most probably, causally related to the activity of the transposable element hobo. We have investigated potential interactions between the two systems of hybrid dysgenesis by studying mixed lines derived from bidirectional crosses between 23.5 MRF and P strains, and analyzed their potentials to induce or suppress the occurrence of dysgenesis. All new lines possess the P induction abilities, as determined by two different procedures, and have also acquired a P cytotype. In contrast, some of them lost their ability to induce the non-P-M dysgenesis, as well as to suppress the action of 23.5 MRF. This loss of the 23.5 MRF induction abilities parallels the selective loss of full-length hobo elements from the genome of these lines, providing further substantiation to the notion that the 23.5 MRF activity is directly linked to this transposable element.

Animals↗
PubMed1988

Cohabitation of KP and full-length P elements in the genome of MR strains inducing P-M-like hybrid dysgenesis in Drosophila melanogaster.

P strains of Drosophila melanogaster are characterized by the presence of both full-length and deletion derivatives of the transposable element P in their genome, and by their ability to induce the syndrome of hybrid dysgenesis among the progeny of certain intra-strain crosses, when introduced through the male parents. In contrast, strains belonging to the M' class, and which were also found to bear P element-homologous sequences, lack this ability and this has been attributed to the presence in the genome of most of these strains of a distinct class of deletion derivatives termed KP, which can suppress the action of functional P factors. Here we demonstrate that KP elements are present, next to full-length ones, in the genome of at least three strains which induce P-M-like dysgenic symptoms, including GD sterility. KP elements form the majority of the P-homologous sequences in the strains MR-h12, 23.5/CyL4 and the latter's derivative 23.5*/Cy. While the first one is a genuine P strain and the second one depicts a strong P cytotype, the third is a genuine M' strain. The hybrid dysgenesis induced by the two 23.5 MRF strains seems to be due, not primarily to the P elements, but to the action of hobo elements.

Animals↗
PubMed1988

Drosophila S virus, a hereditary reolike virus, probable agent of the morphological S character in Drosophila simulans.

Isometric reolike virions were found in all the examined Drosophila simulans flies from two strains (SimES-st and Israel-st) presenting the S phenotype, a maternally inherited morphological trait (abnormalities of bristles). Normal flies of both strains appeared virus-free. Virions were found in the cytoplasm of male and female gonads and epidermal cells, including the bristle-forming cells, which appeared disorganized. Steps of virogenesis were described. A positive correlation was demonstrated between expressivity of the S phenotype and degree of viral infection. This hereditary reolike virus seems to be responsible for the S character of D. simulans and was named DSV (Drosophila S virus).

Animals↗
PubMed1988

[Generalized mucormycosis. Apropos of a case caused by Absidia corymbifera].

This is the case of a woman, 49 year old, suffering from acute lymphoblastic common leukemia, who died from respiratory and cardiac insufficiency 47 days after the onset of aplasia. Autopsy revealed cardiac and cerebral dissemination of pulmonary mycosis. Absidia corymbifera (Mucoraceae, Phycomycete) was shown by culture to be the pathogen involved.

Female↗
PubMed1987

hobo is responsible for the induction of hybrid dysgenesis by strains of Drosophila melanogaster bearing the male recombination factor 23.5MRF.

The male recombination factor 23.5MRF, isolated ten years ago from a natural Greek population of Drosophila melanogaster, has been shown to induce hybrid dysgenesis when crossed to some M strains, in a fashion slightly different from that of most P strains. Furthermore, it was recently shown that 23.5MRF can also induce GD sterility when crossed to specific P strain females (e.g., Harwich, pi 2 and T-007). In these experiments, the P strains mentioned behaved like M strains in that they did not induce sterility in the reciprocal crosses involving 23.5MRF. We extended the analysis to show that 23.5MRF does not destabilize snW(M) and that a derivative with fewer full-length P elements behaves like an M strain toward the same P strains and still retains its dysgenic properties in the reciprocal crosses. We show that there is a strong correlation between the site of dysgenic chromosomal breakpoints induced by 23.5MRF and the localization of hobo elements on the second chromosome, and also that hobo elements are found associated with several 23.5MRF induced mutations. These results suggest that hobo elements are responsible for the aberrant dysgenic properties of this strain, and that they may express their dysgenic properties independent of the presence of P elements.

Animals↗
PubMed1987

The instability of the TE-like mutation Dp(2:2)GYL of Drosophila melanogaster is intimately associated with the hobo element.

We have characterized molecularly several derivatives of the TE-like element Dp(2:2)GYL of Drosophila melanogaster. This highly unstable mutation occurred in a dysgenic cross involving the 23.5 MRF chromosome, and represents an inverted insertional duplication of approximately 130 polytene bands of the paternal 2L, at 50AB of the right arm of the maternal 2R. The instability of this mutation is characterized by deletion of some of duplicated material, by the induction of rearrangements in its vicinity and by the transposition of parts of the original element. We have found that the mobile element hobo is present at , or very near, the breakpoints of all GYL derivatives analysed, demonstrating that hobo is not only active in dysgenic crosses, but also that it can promote genetic instability reminiscent of transposable elements (TE).

Animals↗
PubMed1987

[Ceftriaxone and severe infections in medical resuscitation].

Ceftriaxone was used in 24 medical intensive care patients to treat 8 pulmonary infections, 12 septicaemias, 3 urinary tract infections, 1 meningitis. It was administered at a single intravenous dose of 2 g every 24 h. The therapy was successful, clinically and bacteriologically in 16 patients. The reasons of the failures are analysed. Plasma concentrations were obtained: they demonstrate that ceftriaxone is effective when given once a day in most cases.

Adult↗
PubMed1987

[Anorectal manometry. Practical use in a pediatric surgical clinic].

Over a series of 158 cases of anorectal manometry the authors describe the technique used in a general pediatric surgery department. Results are reported in Hirschsprung's disease specially in the neonatal period, chronic constipation, fecal incontinence after anorectal malformations and meningomyelocele, encopresis. Biofeedback was performed in 28 patients. Technique varies with the etiologies and results are reported. Anorectal manometry to be effective must be simple, reliable, safe and non invasive. The reported technique seems effective for this goal.

Anal Canal↗
PubMed1986

Organization of transcription units around the Drosophila melanogaster rudimentary locus and temporal pattern of expression.

The molecular organization of 90 kb of DNA derived from a region of the X chromosome that encompasses the rudimentary locus of D. melanogaster is presented. This segment spans the cytogenetic region 14F2-3 to 15A1-2, and there are, in addition to the rudimentary gene several transcription units present, whose functions are still unknown. We have determined the pattern of expression of all these genes at several stages of development, and found that they all show a different temporal modulation of their activity. The accumulation of the r product correlates well with the enzymatic activity determined for the protein product of the gene, being highest in very early embryos and adult females.

Animals↗
PubMed1986

Behavioral fever and therapy in a rickettsia-infected Orthoptera.

Gryllus bimaculatus were infected with an intracellular prokaryote, Rickettsiella grylli, then reared either at fixed temperatures or in a temperature gradient (22-36 degrees C) where they could select the temperature they preferred. Only 50% of the infected insects reared at 28 degrees C or less survived after 20 days, against 75% of those reared at 30 degrees C or more and 90% of those in the temperature gradient. Examination of smears of insect tissue showed that all (100%) of the infected insects reared between 23 and 29 degrees C had developed a strong rickettsial infection. Only 20% of the insects reared in a gradient of temperature showed signs of strong infection. Body temperature of crickets in the temperature gradient, recorded using thin thermocouples, was 33 degrees C in infected crickets and 26.6 degrees C in controls. It is concluded that thermoregulatory behavior was used by the insects to produce a fever when infected with Rickettsiella grylli. This protected them and increased survival capacity.

Animal Husbandry↗