In vitro and in vivo effects of glucocorticoids on gene transfer to skeletal muscle.

As a pharmacological approach to potentially improve gene transfer efficiency into skeletal muscle cells, glucocorticoids were shown here to allow efficient transfection of cultured and mouse human myoblasts, human pulmonary A549 cells, but not dog myoblasts, independently of the transfection protocol, the reporter gene and the transcription promoter employed. Transduction with adenovirus was also increased by dexamethasone. Pretreatment of cells 48 h prior to transfection was most effective and was shown to be concentration-dependent. This effect is mediated by binding to the glucocorticoid receptor, but not by glucocorticoid responsive elements present in the vectors. The acute dexamethasone effect could be due to increased plasmid entry into the cells as suggested by Southern blot, whereas the sustained increase of luciferase activity in dexamethasone-treated cultures may be related to intracellular mechanisms following cell entry. In mice in vivo, a similar increase of luciferase activity upon glucocorticoid treatment was found.

Processing of mispaired and unpaired bases in heteroduplex DNA in E. coli.

Bacteriophage lambda and phi X 174 DNAs, carrying sequenced mutations, have been used to construct in vitro defined species of heteroduplex DNA. Such heteroduplex DNAs were introduced by transfection, as single copies, into E. coli host cells. The progeny of individual heteroduplex molecules from each infective center was analyzed. The effect of the presence of GATC sequences (phi X 174 system) and of their methylation (lambda system) was tested. The following conclusions can be drawn: some mismatched base pairs trigger the process of mismatch repair, causing a localized strand-to-strand information transfer in heteroduplex DNA: transition mismatches G:T and A:C are efficiently repaired, whereas the six transversion mismatches are not always readily recognized and/or repaired. The recognition of transversion mismatches appears to depend on the neighbouring nucleotide sequence; single unpaired bases (frameshift mutation "mismatches") are recognized and repaired, some equally efficiently on both strands (longer and shorter), some more efficiently on the shorter (-1) strand; large non-homologies (about 800 bases) are not repaired by the Mut H, L, S, U system, but some other process repairs the non-homology with a relatively low efficiency; full methylation of GATC sequences inhibits mismatch repair on the methylated strand: this is the chemical basis of strand discrimination (old/new) in mismatch correction; unmethylated GATC sequences appear to improve mismatch repair of a G:T mismatch in phi X 174 DNA, but there may be some residual mismatch repair in GATC-free phi X 174, at least for some mismatches.(ABSTRACT TRUNCATED AT 250 WORDS)

Stream nitrate variations explained by ground water head fluctuations in a pyrite-bearing aquifer.

In the context of agricultural nitrogen excesses in northwestern France, pyrite-bearing weathered schist aquifers represent important hydrological compartments due to their capacity to eliminate nitrate (NO3-). Under oxygen-free conditions, nitrate is reduced simultaneously with the oxidation of pyrite leading to the release of sulfate (SO4/2-). The aim of the present study is to identify the hydrological conditions under which the weathered schist ground water influences the stream water chemistry, leading to a decrease in NO3- concentration. We measured the ground water head on a small catchment over weathered schist, near the bank and under the streambed, and analyzed the chemical composition of the ground water as well as the stream water on both seasonal and storm-event timescales. Using SO4/2- as a tracer of the weathered schist ground water, we showed that ground water inflow caused a decrease of NO3- concentration in the stream during the autumn as well as during storm events in spring and summer. In summer, the NO3- concentration was controlled by the sources of the stream, and in winter by the shallow ground water inflow. The effect of the weathered schist ground water on the NO3- depletion remained relatively limited in time. This effect persisted into late autumn as long as the NO3(-) -rich shallow ground water did not feed the stream. The duration and intensity of the effect would be extended by decreasing the shallow ground water inflow, which depends on climate as well as the presence of landscape features such as hedges and buffer zones.

[Outcome of operated transposition of the great vessels]. / Devenir des transpositions des gros vaisseaux opérées.

The object of this report is to describe the long-term outcome of patients operated for transposition of the great vessels. Understanding what we mean by transposition of the great vessels, the surgical options with their advantages, limitations and complications, helps the cardiologist decide on the mode of follow-up, the investigations and even the reoperations that these patients may need. The authors review the results of the literature and their experience over the years with children and adults with congenital heart disease. Although considerable progress has been made in the management of a condition considered to be constantly and often rapidly fatal, most of the procedures which allow patients to have a normal or quasi-normal quality of life have not resolved all the problems and require maintenance of long-term follow-up.

[Microdeletion of the chromosome 22q11 in children: apropos of a series of 49 patients]. / La microdélétion du chromosome 22q11 chez l'enfant: à propos d'une série de 49 patients.

UNLABELLED: Most of the children with Di George syndrome and 60% of patients with velocardiofacial syndrome exhibit a microdeletion within chromosome 22q11. The phenotypic expression of this chromosomal abnormality is highly variable. PATIENTS: Forty-nine children, 0 to 15 years of age, were demonstrated as carriers of a 22q11 microdeletion. The main referral diagnoses were: Di George syndrome (19 cases), velocardiofacial syndrome (14 cases); congenital heart defect with dysmorphism (9 cases); hypoparathyroidism (2 cases). The microdeletion was detected by fluorescent in situ hybridization with probes specific of the 22q11 region. RESULTS: Facial dysmorphism was the only constant feature. A congenital heart defect was present in 84% of cases. Significant hypocalcemia was documented in 51% of cases and thymic hypo or agenesis in 83%. Significant immune deficiency was documented in nine cases. The most frequent associated defects were urinary tract malformations (8 cases). A cleft palate was present in height enfants but velopharyngeal insufficiency was almost constant. Two-thirds of children had psychomotor delay, and five children exhibited behavioral problems. Of the 35 couples of parents tested, eight mothers were found to be carriers of the deletion. CONCLUSION: For the pediatrician, it is essential to know the variability of the clinical picture. The long-term prognosis is conditioned by the possibility of mental retardation and learning disabilities. Parents should be tested for the presence of the deletion. The occurrence of the microdeletion in asymptomatic relatives raises difficult problems in genetic counselling.

[Congenital heart disease and nuchal translucency with normal karyotype. Report of 3 cases]. / Cardiopathie congénitale et clarté nucale avec caryotype normal. A propos de 3 cas.

We report three pregnancies where enlarged nuchal translucency was discovered at the first trimester transvaginal ultrasound examination; congenital heart disease developed later. Two cases of hypoplastic left heart were diagnosed prenatally at the mid-trimester sonographic examination. The pregnancies were terminated. In the third case, a supravalvular pulmonary stenosis was discovered on the second day of life. Further investigations demonstrated a mutation on the elastin locus, thus confirming the diagnosis of Williams-Beuren syndrome. The role of nuchal translucency as a risk marker for congenital heart disease is discussed.

[Physiological basis of fetal and neonatal circulation]. / Bases physiologiques de la circulation foetale et néo-natale.

The extremely reduced nature of the pulmonary circulation, the parallel arrangement of the right and left sides of the heart, and the mixture of oxygenated umbilical blood with the rest of the venous return in the right atrium endow the foetal circulation with its "relatively protected" nature. Thus the majority of cardiac and pulmonary malformations have no effect or cause only minor circulatory disturbances. The transfer of respiratory function from the placenta to the lungs which becomes necessary as soon as the cord is clamped is a highly disturbing event. The pulmonary circulation must be established, the communications of foetal life close (Botal's foramen, ductus arteriosus), and the right and left heart function in series. Such adaptations, certain of which are essential to immediate survival, may require several weeks before completion. Any disease in the newborn, congenital or acquired, respiratory, circulatory, metabolic or other, is accompanied by numerous interwoven consequences. In particular, return to a foetal type circulation by increase or absence of pulmonary resistances could induce a right-left shunt through a fossa ovale which is only asking to open, or even through a ductus arteriosus which is only asking to reopen. Congenital diaphragmatic hernia is no exception is no exception to this rule.

[Sodium supply in operations under extracorporeal circulation in children]. / Apport sodé dans les interventions sous C.E.C. chez l'enfant

In order to explain the edematous appearance found in infants after ECC associated with hyponatremia, the authors studied the supply of sodium per and post-operatively in 42 children aged from 11 days to 13 years undergoing correction of the cardiopathy under ECC. This study enables one to find that there is an inflation of sodium after intervention under ECC, which is even more important, the longer the duration of the ECC. It is not related to a failure in urinary excretion of Na+ and predominates in infants. It is related with the supply of sodium during transfusion and seems to be the cause of certain respiratory complications met with following ECC.

Cardiac catheterization by percutaneous femoral venous approach in infants weighing less than 5 kg: observations in 97 cases.

The technique of cardiac catheterization after percutaneous introduction of a catheter can now be accomplished in neonates thanks to the refinement of the equipment and to the physicians' experience. In 100 catheterizations performed in infants of less than 5 kg, the new technique was utilized 97 times. Thanks to the utilization of introducers it permits Rashkind atrioseptostomy. Its main advantage is the preservation of venous integrity and this allows repeat investigations through the same route.

Transposition of the great arteries. New technique for anatomical correction.

We describe a new technique for the correction of transposition of the great arteries by "detransposition". An aortopulmonary window is created and a patch placed over this and the coronary ostia so that the coronary arteries arisen from the new aorta. Thus, direct surgery on the coronary arteries is avoided with all the complications which may result from this in neonates and infants. A 4.2 kg infant, with transposition and ventricular septal defect, was successfully operated on using this technique. We discuss the indications for this type of operation and conclude that, until we have more experience, it should be used only in children with a left ventricular pressure at least half systemic.

[Behçet's disease in a 2-year-old girl]. / Maladie de Behçet chez une fillette de 2 ans.

The authors report a case of gangrenous stomatitis with lingual and anal ulcers and pericarditis in a 2-year-old girl. They propose the diagnosis of Behçet's syndrome for this patient despite the absence of uveitis.

GATC sequences, DNA nicks and the MutH function in Escherichia coli mismatch repair.

Circular heteroduplex DNAs of bacteriophage phi X174 have been constructed carrying either a G:T (Eam+/Eam3) or a G:A (Bam+/Bam16) mismatch and containing either two, one or no GATC sequences. Mismatches were efficiently repaired in wild-type Escherichia coli transfected with phi X174 heteroduplexes only when two unmethylated GATC sequences were present in phi X174 DNA. The requirements for GATC sequences in substrate DNA and for the E. coli MutH function in E. coli mismatch repair can be alleviated by the presence of a persistent nick (transfection with nicked heteroduplex DNA in ligase temperature-sensitive mutant at 40 degrees C). A persistent nick in the GATC sequence is as effective in stimulating mutL- and mutS-dependent mismatch repair as a nick distant from the GATC sequence and from the mismatch. These observations suggest that the MutH protein participates in methyl-directed mismatch repair by recognizing unmethylated DNA GATC sequences and/or stimulating the nicking of unmethylated strands.

GATC sequence and mismatch repair in Escherichia coli.

The Escherichia coli mismatch repair system greatly improves DNA replication fidelity by repairing single mispaired and unpaired bases in newly synthesized DNA strands. Transient undermethylation of the GATC sequences makes the newly synthesized strands susceptible to mismatch repair enzymes. The role of unmethylated GATC sequences in mismatch repair was tested in transfection experiments with heteroduplex DNA of phage phi 174 without any GATC sequence or with two GATC sequences, containing in addition either a G:T mismatch (Eam+/Eam3) or a G:A mismatch (Bam+/Bam16). It appears that only DNA containing GATC sequences is subject to efficient mismatch repair dependent on E. coli mutH, mutL, mutS and mutU genes; however, also in the absence of GATC sequence some mut-dependent mismatch repair can be observed. These observations suggest that the mismatch repair enzymes recognize both the mismatch and the unmethylated GATC sequence in DNA over long distances. The presence of GATC sequence(s) in the substrate appears to be required for full mismatch repair activity and not only for its strand specificity according to the GATC methylation state.