CYS3, a hotspot of meiotic recombination in Saccharomyces cerevisiae. Effects of heterozygosity and mismatch repair functions on gene conversion and recombination intermediates.

We have examined meiotic recombination at the CYS3 locus. Genetic analysis indicates that CYS3 is a hotspot of meiotic gene conversion, with a putative 5'-3' polarity gradient of conversion frequencies. This gradient is relieved in the presence of msh2 and pms1 mutations, indicating an involvement of mismatch repair functions in meiotic recombination. To investigate the role of mismatch repair proteins in meiotic recombination, we performed a physical analysis of meiotic DNA in wild-type and msh2 pms1 strains in the presence or absence of allelic differences at CYS3. Neither the mutations in CYS3 nor the absence of mismatch repair functions affects the frequency and distribution of nearby recombination-initiating DNA double-strand breaks (DSBs). Processing of DSBs is also similar in msh2 pms1 and wild-type strains. We conclude that mismatch repair functions do not control the distribution of meiotic gene conversion events at the initiating steps. In the MSH2 PMS1 background, strains heteroallelic for frameshift mutations in CYS3 exhibit a frequency of gene conversion greater than that observed for either marker alone. Physical analysis revealed no modification in the formation of DSBs, suggesting that this marker effect results from subsequent processing events that are not yet understood.

Characterization of RNA from Leishmania tropica and Leishmania d.donovani promastigotes.

RNA has been prepared from promastigotes of Leishmania tropica and Leishmania d.donovani using three different methods. Extraction by hot phenol/isothiocyanate gave the best quantitative and qualitative results. The analysis of total RNA on methyl mercuric agarose gels shows that the large rRNA species is nicked: it is composed of a 630 and a 560 kDa molecule. The small rRNA species has a molecular weight of 800,000. Poly(A+) RNA can be translated in a rabbit reticulocyte lysate system. The newly synthesized products comprise high molecular weight proteins and show different patterns using RNA from L. tropica or from L. d. donovani promastigotes.

Molecular cloning and expression of ferritin mRNA in heavy metal-poisoned Xenopus laevis cells.

In a search for genes transcriptionally regulated by metal ions, we have isolated a Xenopus laevis ferritin cDNA clone, XL2-17, from cadmium-poisoned XL2 cells. The large size of the corresponding ferritin mRNA (1.4 kb) is due to the presence of a 629-nucleotide 5'-untranslated region. The Xenopus ferritin sequence is highly isologous with other vertebrate ferritins. In particular, there is a complete sequence identity for the iron-responsive element (IRE) located in the 5'-untranslated region in both XL2-17 and Rana catesbeiana ferritin mRNAs. The position of this IRE is unusual since it is located 489 nucleotides from the 5' end of the ferritin mRNA. Our analysis of phylogenetic relationships among ferritins indicates that all amphibian ferritins thus far sequenced would be more closely related to the mammalian H-type ferritin than to the L-type. The level of ferritin mRNA in XL2 cells rises 10- to 15-fold following exposure of cells to cadmium or copper. This increase is due to both transcriptional and translational regulation. A 10-fold increase was also found at the protein level. These results suggest that ferritin may be a primary detoxification response to heavy metals in Xenopus cells.

Molecular cloning and expression of a metallothionein mRNA in Xenopus laevis.

Metallothioneins (MT) are expressed during early development in species of several groups. To understand MT function in developmental processes, we studied the MT system of Xenopus laevis, a model vertebrate species in experimental embryology. We first purified and sequenced the liver MT from copper-treated animals. This 62-amino-acid protein shares the main structural properties of known vertebrate MT, and is more closely related to avian than to fish or mammalian MT. Using this sequence, we designed oligonucleotide primers to amplify and isolate a MT clone from a XL2 cell line cDNA library. This 752-bp cDNA encodes a putative 62-amino-acid-long protein that is 100% identical with the sequenced MT. Zinc, cadmium, and copper ions are very efficient inducers of MT mRNA accumulation in Xenopus liver and cell lines.

[Hemorrhagic delivery in a full-term abdominal pregnancy with a live infant]. / Délivrance hémorragique lors d'une grossesse abdominale à terme avec enfant vivant.

This is a new case report of a primary abdominal pregnancy with a full-term live baby in a 26 yr old women. The diagnosis was only made at laparotomy. The premature placental separation was followed by massive haemorrhage. Over a period of five days, the patient required a transfusion of 139 blood units and nine surgical explorations before control of the bleeding site could be obtained. Control of the haemorrhage could only be obtained with massive transfusions of fresh platelets and biological monitoring of coagulation by specialized laboratories. This case confirmed the diagnostic difficulties and the need to leave the placenta in situ until control of bleeding sites can be obtained.

[Induction of labor with peridural anesthesia]. / Déclenchement du travail sous anesthésie péridurale.

Epidural anaesthesia for elective induction of labour allows a better planning with many advantages for the medical team. A retrospective study was carried out to know the opinion parturients who benefited from this technique. This induction of labour, though appearing to a slight extent unnatural, is well accepted by the parturients. The reasons of satisfaction are mainly the security of childbirth, but also a better family organization.

[Course of the anaesthesiology and intensive care unit residents in Lorraine, France]. / Parcours des anesthésistes-réanimateurs formés en Lorraine depuis 1996.

OBJECTIVE: The anaesthesiology and intensive care physician demography is becoming critical in most French regions; more than 56% of the residents trained in Lorraine are leaving the area after they graduate. METHODOLOGY: A descriptive and retrospective survey was carried out. The aims of the research were threefold: to ascertain firstly, why residents chose Lorraine in the first instance, secondly their experiences of the training and thirdly their expectations. The target group consisted of 76 former anaesthesia residents dating back to 1996. RESULTS: The response rate was 72.4%. Choosing Lorraine was based on its well-established teaching program (64%) and also on results achieved at National Medical Examination (85%). The academic medical training and working conditions were well-rated. A position was offered to 93% of the residents. Fifty-three percent stated having had previous work experience in the hospital as a decisive factor in taking up a position. By the end of the residency program, only 43.5% of anesthesia physicians remained in Lorraine; i.e., 79% were native to Lorraine and 25% born outside. Reasons given for leaving Nancy were: family (81%), more favourable climate (51%) and to go back to their region of origin (45%). CONCLUSION: Desired improvements would be: better performance of the Lorraine born students at the National Medical Examination, earlier and well-defined job offers, better communication within the team and consideration of the family situation as a whole.

[Assessment of hygiene practices in anaesthesia between 1998 and 2007 in Lorraine]. / Evaluation des pratiques d'hygiène en anesthésie entre 1998 et 2007 en Lorraine.

OBJECTIVES: To study the assessment of hygiene practices in anaesthesia in Lorraine between 1998 and 2007, after recommendations from the French Society of Anaesthesia and Reanimation (SFAR) in December 1997, and different local actions. STUDY DESIGN: Two surveys performed at a nine-year interval in Lorraine hospitals. POPULATION AND METHOD: Questionnaires about risk infection management and hygiene practices were sent by post to all anaesthetists, nurse anaesthetists and recovery room nurses in 1998 (n=279) and in 2007 (n=259). RESULTS: Between the two surveys multidrug-resistant bacteria signalling, movements of the staff in operating rooms, septic isolation protocol and management of single-use disposable anaesthesia material have been improved (p<0.05). Central venous catheters are less performed in recovery rooms and rings wearing decreased by 16% (p<0.05). Wearing of nonsterile gloves for peripheral venous catheter and intubation is not generalized (p<0.05). About half of the hospitals have cleanup procedures of anaesthesia furniture. Washing of hands by anaesthesia staff is not sometimes respected but it's more frequent for medicine preparation and between two operations. A good skin disinfection (cleaning - rinsing - drying - antiseptic) is more recurrent in 2007 (61.4%) than in 1998 (41.9%) for arterial catheter. Wearing of glasses for intubation is each times rare, about 15%. CONCLUSION: Hygiene practices in anaesthesia in Lorraine have been improved between the two surveys by recommendations from the Sfar and the work of the Antenne Régional de Lorraine (audits, manuals, formations). Promising progress has been made but some points must still be worked on.

Anesthesia of the rabbit.

The authors evaluate the results of 150 anesthesias of rabbits in experimental surgery employing various operations. The use of Alfathesin leads to rapid and deep anesthesia with awakening occurring in very good conditions. The technique isparticularly recommended for short operations. Satisfactory cardiovascular and respiratory conditions can be maintained by tracheal intubation together with artificial ventilation, which allows for long and difficult surgical procedures.

[Value of the 2000 radiocom system for a SAMU in a rural area]. / Intérêt du système radiocom 2,000 pour un SAMU en zone rurale.

The department "Meuse" is a region with a low density of population (190,000 inhabitants). The creation of a "SAMU" is quite recent (February 1988). The financial means allowed were limited so they didn't enable us to develop a radio netword peculiar to the "SAMU". The arguments which made us adopt the use of the 2000 Radiocom as a basic means of communication for "SAMU 55" are: immediate creation; reduced installation cost; preservation of the medical secret and possibility of extension.

Endogenous factors possessing lymphoid chalone properties, purified by chromatography.

Lymphoid chalone extracts, obtained from bovine spleen were purified on chromatographic columns: in the first step of the procedure, exclusion chromatography on Sephadex G75, and ion exchange chromatography on DEAE Sephadex were applied. A purified, active material was thus obtained. Upon thin layer chromatography, this fraction was shown to contain 3-4 UV absorbing components and 2 ninhydrin positive components. Further purification on Biogel P2, on Sephadex G10 and preparative thin layer chromatography, showed that the biological activity was located in small molecular weight components which belong to the polypeptide series. The ultraviolet absorbing components were identified as known nucleosides. The purified material shows an inhibitory effect on the uptake of 3H-thymidine by lymphocytes, as well as on mitogen induced lymphocyte transformation and haemolysin plaque forming cells. Furthermore, this inhibitory effect is specific for lymphoid cells.

Inhibition of tRNA methylation in vitro and in whole cells by an oncostatic S-adenosyl-homocysteine (SAH) analogue: 5'-deoxy 5'-S-isobutyl adenosine (SIBA).

A high increase in the amount of methylated tRNA bases was found in vivo in Rous sarcoma virus infected and transformed chick embryo fibroblasts in comparison with normal cells, tRNA methylases extracted from transformed cells showed also higher activity in vitro with a heterologous substrate. 5'-deoxy-5'-S-isobutyl adenosine, (a structural analogue of S-adenosyl-L homocysteine), which inhibits virus-induced cell transformation, inhibits also the increase of incorporation of labelled methyl groups into tRNA in infected and transformed cells. When normal cells are grown in the presence of this inhibitor, undermethylated tRNAs are obtained. The effect of the drug is different in normal, infected and transformed cells. The methylation of the different bases is inhibited in vitro and in vivo to various extent. The effect of this substance on tRNA methylation may be the cause of its inhibitory effect on cell transformation.

Identification of some metabolic products of 5' -deoxy-5' -S-isobutylthioadenosine, an inhibitor of virus-induced cell transformation.

5' -Deoxy-5' -S-isobutylthioadenosine (iBuS)5' Ado has been shown to be rapidly degraded to 5-deoxy-5-S-isobutylthioribose and adenine in procaryotes. In chick embryo fibroblasts there are two metabolic pathways for (iBuS)5' Ado degradation: (a) oxidative deamination into 5' -deoxy-5'-S-isobutylthioinosine (the main product) and (b) hydrolysis into 5-deoxy-5-S-isobutylthioribose plus adenine. The latter reaction is not due to bacterial contamination, since the same results were obtained under sterile conditions and in chick embryo fibroblasts in culture. The inhibition of the virus-induced cell transformation reported by us previously was due to (iBuS)5' Ado rather than to the main metabolic product of this molecule in chick embryo fibroblasts.

Changes in methylation pattern of albumin and alpha-fetoprotein genes in developing rat liver and neoplasia.

To determine whether methylation changes in specific DNA sequences of the albumin and AFP genes are implicated in the modulation of transcriptional activity during rat liver development and neoplasia we have analysed the methylation pattern of C-C-G-G sequences within these genes in DNA isolated from fetal and adult hepatocytes, from adult kidney and from a clonal hepatoma cell line which produces AFP but no albumin. We have assayed for methylation of the internal cytosine of this sequence by using the restriction enzyme isoschizomers HpaII and MspI. 32P-labelled cloned cDNA probes were used to reveal the albumin and AFP gene containing fragments. Genomic subclones of the albumin gene were also utilized as molecular probes to measure quantitatively the level of methylation of 6 specific sites within the albumin gene in the different DNA samples. The results indicate that methylation changes at the sites analysed are not responsible for the changes in gene activity during rat liver development. Further they demonstrate that: 1) extensively methylated genes can be actively transcribed; 2) prominent changes in methylation of specific genes during normal development are not necessarily related to alterations in gene activity.

[Postoperative pulmonary complications following surgery for carcinoma of the esophagus]. / Complications pulmonaires post-opératoires de la chirurgie carcinologique de l'oesophage.

Pulmonary complications frequently occur during the postoperative period following surgery for neoplasms of the oesophagus. The aetiology varies according to the time of their onset but the clinical signs and treatment are essentially the same. The problems encountered and related either to anaesthesia, to the surgical approach to the position of the patient. It is after the third day that complication develop related at one and the same to the past history, classical in such patients, (tobacco, chronic bronchitis, alcoholism) and the ectopic position of an abdominal viscus.

[Mechanisms and control of meiotic recombination in the yeast Saccharomyces cerevisiae]. / Mécanismes et contrôles de la recombinaison méiotique chez la levure Saccharomyces cerevisiae.

Recent studies in Saccharomyces cerevisiae have provided new insights in our understanding of the molecular mechanisms of meiotic recombination. Meiosis-specific DNA double-strand breaks have been detected and have been shown to be the lesions that initiate recombination events. These are located mostly in promoter regions where the chromatin is in an open configuration, and cluster in domains along the chromosome. They are likely to be made by a topoisomerase II-like protein encoded by the SPO11 gene. Several DNA intermediates in the meiotic double strand-break repair pathway have been characterised and several multi-protein complexes have been identified and shown to be involved at different steps in the repair pathway. The conservation of these protein complexes in higher eukaryotes suggests that the meiotic recombination mechanism could be conserved. With the application of the well characterised genetical, molecular, cytological and biochemical techniques and the recently developed technology for genomic studies (biochips), we can expect a rapid increase in our comprehension of the meiotic recombination process.