A high-intensity highly coherent soft X-ray femtosecond laser seeded by a high harmonic beam

Synchrotrons have for decades provided invaluable sources of soft X-rays, the application of which has led to significant progress in many areas of science and technology. But future applications of soft X-rays--in structural biology, for example--anticipate the need for pulses with much shorter duration (femtoseconds) and much higher energy (millijoules) than those delivered by synchrotrons. Soft X-ray free-electron lasers should fulfil these requirements but will be limited in number; the pressure on beamtime is therefore likely to be considerable. Laser-driven soft X-ray sources offer a comparatively inexpensive and widely available alternative, but have encountered practical bottlenecks in the quest for high intensities. Here we establish and characterize a soft X-ray laser chain that shows how these bottlenecks can in principle be overcome. By combining the high optical quality available from high-harmonic laser sources (as a seed beam) with a highly energetic soft X-ray laser plasma amplifier, we produce a tabletop soft X-ray femtosecond laser operating at 10 Hz and exhibiting full saturation, high energy, high coherence and full polarization. This technique should be readily applicable on all existing laser-driven soft X-ray facilities.

A novel mechanism of action for v-ErbA: abrogation of the inactivation of transcription factor AP-1 by retinoic acid and thyroid hormone receptors

Ligand-activated retinoic acid receptor alpha (RAR alpha) and c-ErbA alpha repress the AP-1-mediated transcriptional activation of the interstitial collagenase gene promoter by specifically decreasing the activity of the AP-1 transcription factor. On the other hand, the v-ErbA oncoprotein fails to repress the AP-1 activity and acts as a dominant negative oncoprotein by overcoming the repression of the AP-1 activity induced by RAR alpha and c-ErbA alpha. This maintenance by v-ErbA of a fully active AP-1 complex is correlated with the abrogation by this same oncogene product of the growth-inhibitory response of chicken embryo fibroblasts to retinoic acid treatment. This new mechanism of action of v-ErbA together with its previously discovered dominant repressor effect on transcription of thyroid hormone-activated target genes may explain the contribution of the v-erbA oncogene to sarcomatogenic and leukemogenic transformation.

Recombinant antigens to detect Toxoplasma gondii-specific immunoglobulin G and immunoglobulin M in human sera by enzyme immunoassay

We have evaluated the diagnostic utility of eleven Toxoplasma gondii recombinant antigens (P22 [SAG2], P24 [GRA1], P25, P28 [GRA2], P29 [GRA7], P30 [SAG1], P35, P41 [GRA4], P54 [ROP2], P66 [ROP1], and P68) in immunoglobulin G (IgG) and IgM recombinant enzyme-linked immunosorbent assays (Rec-ELISAs). Following an initial evaluation, six recombinant antigens (P29, P30, P35, P54, P66, and P68) were tested in the IgG and IgM Rec-ELISAs with four groups of samples which span the toxoplasmosis disease spectrum (negative, chronic infection, acute infection, and recent seroconversion). Our results suggest that the combination of P29, P30, and P35 in an IgG Rec-ELISA and the combination of P29, P35, and P66 in an IgM Rec-ELISA can replace the tachyzoite antigen in IgG and IgM serologic tests, respectively. The relative sensitivity, specificity, and agreement for the IgG P29-P30-P35 Rec-ELISA were 98.4, 95.7, and 97.2%, respectively. The resolved sensitivity, specificity, and agreement for the IgM P29-P35-P66 Rec-ELISA were 93.1, 95.0, and 94. 5%, respectively. Relative to the tachyzoite-based immunocapture IgM assay, the IgM P29-P35-P66 Rec-ELISA detects fewer samples that contain IgG antibodies with elevated avidity from individuals with an acute toxoplasmosis.

Expression patterns of GASA genes in Arabidopsis thaliana: the GASA4 gene is up-regulated by gibberellins in meristematic regions

The GASA gene family previously identified in Arabidopsis belongs to a wide-spread class of genes found in mono- and dicotyledonous plants, all structurally related to the original GA-regulated GAST1 gene from tomato. They encode small peptides (97 to 112 residues) of unknown function sharing a 60 amino acid conserved C-terminal domain comprising twelve conserved cysteine residues which define a pattern not related to other known cysteine-rich motifs. Northern blot hybridization analysis revealed sequential expression of three genes during flowering, silique development and seed germination. GASA4 transcripts were detected in flower buds. GASA1 transcripts markedly accumulated in siliques, about five days after pollination, and correlated with the peak of GA biosynthesis at this stage of silique development. GASA3 transcripts accumulated at the end of the maturation stage of the silique, and transcripts were still present in dry seeds but degraded rapidly during imbibition. In addition, the GASA4 gene was again actively transcribed after germination and this expression was shown to be dependent on the presence of GAs in GA-deficient mutants. Immunoblot analysis confirmed the presence of the GASA4 gene product in flower buds, seedlings and roots. We focused on the GASA4 gene and characterized its expression. The upstream region (-890 to +128) was fused to the GUS reporter gene. GASA4/GUS expression was detected in transgenic Arabidopsis primarily in all meristematic regions, including vegetative, inflorescence and floral meristems, as well as primary and lateral root tips. In a GA-deficient background (ga1-3), GUS activity in the vegetative meristem was detected only in the presence of supplied GA. In root and flower meristems, basal GUS activity was slightly enhanced by exogenous GA. Interestingly, GA strongly inhibit GUS activity in expanding cotyledons and leaves in ga1-3 mutants supplied with exogenous GAs, as well as in the wild type. The GA-dependent meristem-specific expression pattern suggests that the GASA4 protein plays a role in dividing cells rather than in elongating cells.

Molecular and biochemical heterogeneity of class B carbapenem-hydrolyzing beta-lactamases in Chryseobacterium meningosepticum

Although the carbapenem-hydrolyzing beta-lactamase (CHbetaL) BlaB-1 is known to be in Chryseobacterium meningosepticum NCTC 10585, a second CHbetaL gene, bla(GOB-1), was cloned from another C. meningosepticum clinical isolate (PINT). The G+C content of bla(GOB-1) (36%) indicated the likely chromosomal origin of this gene. Its expression in Escherichia coli DH10B yields a mature CHbetaL with a pI of 8.7 and a relative molecular mass of 28.2 kDa. In E. coli, GOB-1 conferred resistance to narrow-spectrum cephalosporins and reduced susceptibility to ureidopenicillins, broad-spectrum cephalosporins, and carbapenems. GOB-1 had a broad-spectrum hydrolysis profile including penicillins and cephalosporins (but not aztreonam). The catalytic efficiency for meropenem was higher than for imipenem. GOB-1 had low amino acid identity with the class B CHbetaLs, sharing 18% with the closest, L-1 from Stenotrophomonas maltophilia, and only 11% with BlaB-1. Most of the conserved amino acids that may be involved in the active site of CHbetaLs (His-101, Asp-103, His-162, and His-225) were identified in GOB-1. Sequence heterogeneity was found for GOB-1-like and BlaB-1-like beta-lactamases, having 90 to 100% and 86 to 100% amino acid identity, respectively, among 10 unrelated C. meningosepticum isolates. Each isolate had a GOB-1-like and a BlaB-1-like gene. The same combination of GOB-1-like and BlaB-1-like beta-lactamases was not found in two different isolates. C. meningosepticum is a bacterial species with two types of unrelated chromosome-borne class B CHbetaLs that can be expressed in E. coli and, thus, may represent a clinical threat if spread in gram-negative aerobes.

Measuring particle size distribution and mass concentration of nanoplastics and microplastics: addressing some analytical challenges in the sub-micron size range

HYPOTHESIS

The implementation of the proposal from the European Chemical Agency (ECHA) to restrict the use of nanoplastics (NP) and microplastics (MP) in consumer products will require reliable methods to perform size and mass-based concentration measurements. Analytical challenges arise at the nanometre to micrometre interface, e.g., 800 nm-10 µm, where techniques applicable at the nanometre scale reach their upper limit of applicability and approaches applicable at the micrometre scale must be pushed to their lower limits of detection.

EXPERIMENTS

Herein, we compared the performances of nine analytical techniques by measuring the particle size distribution and mass-based concentration of polystyrene mixtures containing both nano and microparticles, with the educational aim to underline applicability and limitations of each technique.

FINDINGS

Light scattering-based measurements do not have the resolution to distinguish multiple populations in polydisperse samples. Nanoparticle tracking analysis (NTA), nano-flowcytometry (nFCM) and asymmetric flow field flow fractionation hyphenated with multiangle light scattering (AF4-MALS) cannot measure particles in the micrometre range. Static light scattering (SLS) is not able to accurately detect particles below 200 nm, and similarly to transmission electron microscopy (TEM) and flow cytometry (FCM), is not suitable for accurate mass-based concentration measurements. Alternatives for high-resolution sizing and concentration measurements in the size range between 60 nm and 5 µm are tunable resistive pulse sensing (TRPS) and centrifugal liquid sedimentation (CLS), that can bridge the gap between the nanometre and micrometre range.

Oxacillinase-mediated resistance to cefepime and susceptibility to ceftazidime in Pseudomonas aeruginosa

Pseudomonas aeruginosa clinical isolate SOF-1 was resistant to cefepime and susceptible to ceftazidime. This resistance phenotype was explained by the expression of OXA-31, which shared 98% amino acid identity with a class D beta-lactamase, OXA-1. The oxa-31 gene was located on a ca. 300-kb nonconjugative plasmid and on a class 1 integron. No additional efflux mechanism for cefepime was detected in P. aeruginosa SOF-1. Resistance to cefepime and susceptibility to ceftazidime in P. aeruginosa were conferred by OXA-1 as well.

Molecular fingerprinting of Mycobacterium tuberculosis and risk factors for tuberculosis transmission in Paris, France, and surrounding area

Forty-three percent of the tuberculosis cases reported in France are from the Ile de France region. The incidence of tuberculosis in this region is 33 cases per 100,000 inhabitants, twice the national average. A restriction fragment length polymorphism (RFLP) analysis was performed with clinical isolates of Mycobacterium tuberculosis isolated during 1995 in 10 hospitals in Paris and surrounding areas to detect tuberculosis transmission and define the factors associated with clustering in this population. The molecular markers used were the insertion sequence IS6110 and the direct repeat (DR) sequence. Social, demographic, and clinical data were collected from the patients' medical files. Ten patients with isolates with a single copy of IS6110 were excluded from further analysis. Twenty-four patients with false-positive cultures due to laboratory contamination (based on RFLP analysis with IS6110 and examination of patient data) were also excluded. The study was then conducted with 272 strains isolated from 272 patients. Further fingerprinting was performed by using the DR element with strains with patterns by RFLP analysis with IS6110 that differed by one band only and strains with identical patterns by RFLP analysis with IS6110 and with low numbers of copies of IS6110. The combined use of both markers identified unique patterns for 177 strains and clustered 95 (35.7%) strains in 26 groups, each containing isolates from 2 to 12 patients. The clustering was strongly associated with homelessness and the male sex. It was not associated with age, birth in a foreign country, human immunodeficiency virus positivity, or residence in hostels or prison. Isolates from homeless people were often included in large clusters, and homeless people could be the source of tuberculosis transmission for more than 50% of the clustered patients. These results suggest that homeless people play a key role in the spread of M. tuberculosis in the community and that poor socioeconomic conditions are the main risk factors associated with active tuberculosis transmission.

Pyrimethamine-sulfadoxine treatment of congenital toxoplasmosis: follow-up of 78 cases between 1980 and 1997. Reims Toxoplasmosis Group

The purpose of this study was to determine the clinical and immunological outcome of 78 children with congenital toxoplasmosis treated with the pyrimethamine-sulfadoxine combination between 1980 and 1997.

METHODS

Children were divided into 3 groups according to the initial duration of treatment (always including folinic acid, 5 mg/week by mouth), as follows: pyrimethamine (1.25 mg/kg every 15 d) + sulfadoxine (25 mg/kg every 15 d) for 12 months (Group 1, 47 children), or for 24 months, with or without prenatal therapy (respectively, Group 2, 19 children, and Group 3, 12 children).

RESULTS

Chorioretinitis occurred in 23% of these 78 children. Four children had unilateral blindness, 1 had mild epileptic fits and 1 had psychomotor retardation. The lowest rate of sequelae were in Groups 2 and 3. Immunological rebounds, generally without clinical repercussions, occurred frequently (90% of cases on average) during, or more often after therapy, regardless of the treatment duration. Treatment was always well tolerated.

CONCLUSIONS

Our current treatment strategy for congenital toxoplasmosis consists of a 24-month course of pyrimethamine-sulfadoxine (Fansidar) combined with folinic acid (Lederfoline). If the prenatal diagnosis is positive, we also prescribe this treatment to the mother until delivery. This combination offers satisfactory compliance, adequate serum concentrations, and good preventive efficacy.

Artificial urinary sphincter implantation for neurogenic bladder: a multi-institutional study in 107 children

OBJECTIVES

To evaluate the outcome of implantation of the AMS 800 artificial urinary sphincter in children with neurogenic bladder.

PATIENTS AND METHODS

The records of 107 children (74 boys and 33 girls) treated for neurogenic urinary incontinence by implantation of the AMS 800 artificial sphincter between 1983 and 1993 were reviewed retrospectively. The underlying cause of incontinence in 92 patients was spina bifida, the mean age at implantation was 13.7 years and 30 patients had undergone previous bladder neck surgery. Implantation was carried out in combination with another surgical procedure in 24.3% of patients. The mean follow-up was 61 months (minimum 12).

RESULTS

The mean operational life of the sphincter was 56 months. No deaths occurred but removal of the artificial sphincter was necessary in 20 patients (19%). Surgical revision was not required in 44 patients (41%) but at least one revision was performed in 63 and more than one in 42. There were 21 mechanical failures, 40 surgical complications and 39 cases involving changes in the dynamics of bladder function. Of the 87 children (81%) in whom the device is still in place, 72 are completely continent (83%), 10 are slightly wet, and five are incontinent. The overall success rate was 77%.

CONCLUSIONS

The results emphasize that for successful implantation of an artificial urinary sphincter in children, the pre-operative bladder capacity must be sufficient and previous surgery should not have been performed on the bladder neck, the site of choice for implantation in children. Sphincterotomy is not always necessary in paediatric patients. Children and parents should be informed of the high complication rate and the need for long-term follow-up.

Use of Fourier-transform infrared spectroscopy for typing of Candida albicans strains isolated in intensive care units

Comparative studies of Candida albicans strains are essential for proving cross-infections in epidemiological investigations. Typing of C. albicans strains is mainly based on genotypic methods. Fourier-transform infrared (FTIR) spectroscopy is described in this study as a novel phenotypic approach to the typing of C. albicans. The first step in the approach was the standardization of sample preparation (culture conditions and sampling parameters) and acquisition and classification parameters (spectral acquisition, spectral window selection, classification algorithm, and heterogeneity threshold). The second step consisted of validating the established parameters with a set of 79 strains of C. albicans isolated over 4 months from nine patients hospitalized in two intensive care units. Strains were isolated from multiple anatomical sites with repeated sampling. FTIR spectroscopy results were compared to randomly amplified polymorphic DNA (RAPD) results; this analysis showed that the amplification patterns of strains isolated from a given patient were identical and that different patients had different profiles. FTIR spectroscopy data were analyzed by hierarchical clustering performed with the second-derivative spectra. This classification revealed nine groups, one per patient. Only one spectrum out of 79 was misclassified by the FTIR spectroscopy method. RAPD and FTIR spectroscopy results were in good agreement, showing that, when nosocomial candidiasis transmission is suspected and urgent information is needed, this technique may be useful as a quick identification tool to give solid clues before confirmation by a genotypic method.

Quality of Life and Continence in Patients with Spina Bifida

PURPOSE

Spina bifida (SB) is the most common congenital cause of incontinence in childhood. This study attempts to determine the relationships between urinary/faecal incontinence, methods of management, and Health Related Quality of Life (HRQoL) in people with SB.

PATIENTS AND METHOD

A total of 460 patients (300 adults and 160 adolescents) from six centres in France have taken part in this cross-sectional study. Clinical outcome measures included walking ability, urinary/faecal continence, and medical management. HRQoL was assessed using the SF36 in adults and the VSP in adolescents and their parents. Univariate and multivariate analysis was used to determine the relationships between clinical parameters and HRQoL.

RESULTS

HRQoL were significantly lower than in the general population. Adult women had significantly lower scores than men, and adolescent females had significantly lower scores for psychological well being. We did not found strong relationship between incontinence and HRQoL in this population. Moreover patients surgically managed for urinary/fecal incontinence did not show significantly higher scores of HRQoL.

CONCLUSION

Using generic HRQoL measures, urinary/faecal incontinence and their medical management may not play a determinant role in HRQoL of persons with SB. However many other factors affect HRQoL in these patients. A longitudinal study design is recommended to assess whether incontinence management is associated with improved HRQoL.

Early neonatal diagnosis of congenital toxoplasmosis: value of comparative enzyme-linked immunofiltration assay immunological profiles and anti-Toxoplasma gondii immunoglobulin M (IgM) or IgA immunocapture and implications for postnatal therapeutic strategies

Diagnostic strategies for congenital toxoplasmosis have changed profoundly in recent years. Immunological diagnostic methods, long considered disappointing, can now be used at a very early stage. Over a 3-year period, 1,050 infants at risk of congenital toxoplasmosis (born to 1,048 mothers infected during pregnancy) were monitored for a minimum of 12 months and a maximum of 7 years. More than 6,000 serum specimens were analyzed by comparative mother-infant immunological profiles (CIPs) based on an enzyme-linked immunofiltration assay (ELIFA) and an immunocapture method for the detection of specific immunoglobulin M (IgM) and IgA. IgG antibodies were also titrated. One hundred three cases of congenital toxoplasmosis were demonstrated. The CIP-ELIFA method had a better diagnostic yield (sensitivity, 90%) than specific IgM and/or IgA detection by immunocapture assay (sensitivity, 77%). By using a combination of these tests, congenital infection was diagnosed in the first month and the first 3 months of life in 90 and 94% of infants with toxoplasmosis, respectively, with a specificity of 99.8% and a positive predictive value of 99% at 8 months of age. This dual diagnostic approach (ELIFA and IgM-IgA immunocapture) is highly efficient and has important implications for therapy. Indeed, early postnatal diagnosis based on objective evidence enables therapy with pyrimethamine-sulfadoxine to be started immediately for 24 months, while spiramycin (which used to be given preventively for 9 to 12 months to all infants at risk) can be stopped after the first 3 months of life.

Efficient transmission of two different sheep scrapie isolates in transgenic mice expressing the ovine PrP gene

We produced transgenic mice expressing the sheep prion protein to obtain a sensitive model for sheep spongiform encephalopathies (scrapie). The complete open reading frame, with alanine, arginine, and glutamine at susceptibility codons 136, 154, and 171, respectively, was inserted downstream from the neuron-specific enolase promoter. A mouse line, Tg(OvPrP4), devoid of the murine PrP gene, was obtained by crossing with PrP knockout mice. Tg(OvPrP4) mice were shown to selectively express sheep PrP in their brains, as demonstrated in mRNA and protein analysis. We showed that these mice were susceptible to infection by sheep scrapie following intracerebral inoculation with two natural sheep scrapie isolates, as demonstrated not only by the occurrence of neurological signs but also by the presence of the spongiform changes and abnormal prion protein accumulation in their brains. Mean times to death of 238 and 290 days were observed with these isolates, but the clinical course of the disease was strikingly different in the two cases. One isolate led to a very early onset of neurological signs which could last for prolonged periods before death. Independently of the incubation periods, some of the mice inoculated with this isolate showed low or undetectable levels of PrPsc, as detected by both Western blotting and immunohistochemistry. The development of experimental scrapie in these mice following inoculation of the scrapie infectious agent further confirms that neuronal expression of the PrP open reading frame alone is sufficient to mediate susceptibility to spongiform encephalopathies. More importantly, these mice provide a new and promising tool for studying the infectious agents in sheep spongiform encephalopathies.

Molecular and biological characteristics of Toxoplasma gondii isolates from wildlife in France

Toxoplasma gondii isolates have been classified into 3 genetic types. Little is known about genotypes of T. gondii isolates in wild animals in Europe. In this report, genotypes of T. gondii isolates from wildlife in France are described. Sera from wildlife were tested for antibodies to T. gondii with the modified agglutination test, and the hearts from animals with titers superior or equal to 1:6 were bioassayed individually in mice. T.gondii was isolated from 9 of 14 seropositive red foxes (Vulpes vulpes), 12 of 33 roe deer (Capreolus capreolus), 1 of 4 deer (Cervus elaphus), 1 of 7 mouflons (Ovis gmelini musimon) and 1 of 2 common mallards (Anas platyrhynchos). No isolate was obtained by bioassay in mice of 1 fallow deer (Dama dama) and of 3 European brown hares (Lepus europaeus). Genotyping of the 24 isolates using PCR-RFLP and microsatellite markers indicated that all were type II and none of these Toxoplasma isolates was virulent for mice.

Genetic characterization of Toxoplasma gondii from wild boar (Sus scrofa) in France

Toxoplasma gondii strains isolated from domestic animals and humans have been classified into three clonal lineages types I-III, with differences in terms of pathogenicity to mice. Much less is known on T. gondii genotypes in wild animals. In this report, genotypes of T. gondii isolated from wild boar (Sus scrofa) in France are described. During the hunting seasons 2002-2008, sera and tissues of individuals from two French regions, one continental and one insular, were tested for Toxoplasma infection. Antibodies to T. gondii were found in 26 (17.6%) of 148 wild boars using the modified agglutination test (MAT, positivity threshold: 1:24). Seroprevalence was 45.9% when considering a threshold of 1:6. Hearts of individuals with a positive agglutination (starting dilution 1:6) (n=60) were bioassayed in mice for isolation of viable T. gondii. In total, 21 isolates of T. gondii were obtained. Genotyping of the isolates using 3 PCR-restriction fragment length polymorphism markers (SAG1, SAG2 and GRA7) and 6 microsatellite loci analysis (TUB2, TgM-A, W35, B17, B18 and M33) revealed that all belonged to type II lineage. These results underline that wild boar may serve as an important reservoir for transmission of T. gondii, and that strains present in wildlife may not be different from strains from the domestic environment.

EMF1, a novel protein involved in the control of shoot architecture and flowering in Arabidopsis

Shoot architecture and flowering time in angiosperms depend on the balanced expression of a large number of flowering time and flower meristem identity genes. Loss-of-function mutations in the Arabidopsis EMBRYONIC FLOWER (EMF) genes cause Arabidopsis to eliminate rosette shoot growth and transform the apical meristem from indeterminate to determinate growth by producing a single terminal flower on all nodes. We have identified the EMF1 gene by positional cloning. The deduced polypeptide has no homology with any protein of known function except a putative protein in the rice genome with which EMF1 shares common motifs that include nuclear localization signals, P-loop, and LXXLL elements. Alteration of EMF1 expression in transgenic plants caused progressive changes in flowering time, shoot determinacy, and inflorescence architecture. EMF1 and its related sequence may belong to a new class of proteins that function as transcriptional regulators of phase transition during shoot development.

Tracheobronchial ruptures from blunt thoracic trauma in children

BACKGROUND/PURPOSE

Tracheobronchial ruptures in blunt thoracic trauma in children are rare. The aim of this study was to suggest the means of an early diagnosis and a conservative management as often as possible.

METHODS

Sixteen cases of tracheobronchial ruptures by blunt thoracic trauma were observed over 26 years in 9 regional pediatric centers.

RESULTS

There were 12 boys and 4 girls, from ages 1 hour to 17 years. Nine children presented with associated lesions. Fibroscopy established the following diagnosis: 8 tracheal wounds and 8 bronchial wounds. Six children were operated on within 18 hours (on average) after installation of a thoracic drainage. Two lobectomies, 3 ideal tracheal sutures, and 1 bronchial suture were performed. Seven children were treated exclusively by thoracic drainage. Two of them were intubated through the lesion, leading to a transitory endoprothesis accompanied or not by an external thoracic drainage. One infant recovered spontaneously. There were no deaths in this series. Two recurrent postoperative nerve injuries were noted, one of which was a transitory spontaneously resolutive scar bud and one a granuloma treated by laser. Three times, a stenosis occurred after a conservative management. Two were operated on.

CONCLUSIONS

Tracheobronchial ruptures in children are rare. An early fibroscopy holds an important place in the approach of this pathology. Treatment is variable, based on thoracic lesions, their tolerance by the child, and associated lesions. Surgery is not the only therapy because conservative treatment by simple thoracic drainage or lesion intubation has proved effective.

Meiotic instability of human minisatellite CEB1 in yeast requires DNA double-strand breaks

Minisatellites are tandemly repeated DNA sequences of 10-100-bp units. Some minisatellite loci are highly unstable in the human germ line, and structural analysis of mutant alleles has suggested that repeat instability results from a recombination-based process. To provide insights into the molecular mechanism of human minisatellite instability, we developed Saccharomyces cerevisiae strains carrying alleles of the most unstable human minisatellite locus, CEB1 (ref. 2). We observed that CEB1 is destabilized in meiosis, resulting in a variety of intra- and inter-allelic gains or losses of repeat units, similar to rearrangements described in humans. Using mutations affecting the initiation of recombination (spo11) or mismatch repair (msh2 pms1 ), we demonstrate that meiotic destabilization depends on the initiation of homologous recombination at nearby DNA double-strand break (DSBs) sites and involves a 'rearranged heteroduplex' intermediate. Most of the human and yeast data can be explained and unified in the context of DSB repair models.

Vinorelbine plus trastuzumab combination as first-line therapy for HER 2-positive metastatic breast cancer patients: an international phase II trial

The aim of this international phase II trial was to determine the efficacy and safety profile of weekly vinorelbine plus trastuzumab as first-line chemotherapy for women with HER 2-overexpressing metastatic breast cancer. Sixty-nine patients with tumours overexpressing HER 2 received vinorelbine: 30 mg m⁻² week⁻¹ and trastuzumab: 4 mg kg⁻¹ on day 1 as a loading dose followed by 2 mg kg⁻¹ week⁻¹ starting on day 8. Sixty-two patients were evaluable for response and 69 patients were evaluable for toxicity. The overall response rate was 62.9%. The median time to response was 8.4 weeks, the median duration of response was 17.5 months, the median progression-free survival was 9.9 months (95% CI, 5.6–12.1) and the one-year progression-free survival was 39.1%. The median survival for all patients was 23.7 months (95% CI, 18.4–32.6). This regimen was safe: grade 3–4 neutropenia were observed over 17.7% of courses in 83.8% of patients, with only two episodes of febrile neutropenia (0.1%) in two patients (2.9%). Only one patient discontinued treatment due to grade 3 symptomatic cardiac dysfunction that resolved with therapy. Vinorelbine plus trastuzumab is one of the most active treatment regimens for patients with HER 2-positive metastatic breast cancer and demonstrates a very favourable safety profile allowing prolonged treatment with long-term survival. This study has been presented in part at the following conferences: The San Antonio Breast Cancer Symposium, San Antonio, TX, USA, 2003; The American Society of Clinical Oncology, Orlando, FL, USA, 2005.

Effects of T3R alpha 1 and T3R alpha 2 gene deletion on T and B lymphocyte development

Thyroid hormones bind to several nuclear receptors encoded by T3R alpha and T3R beta genes. There is now accumulating evidence that thyroid hormones act on the immune system. Indeed, mice deficient for thyroid hormones show a reduction in lymphocyte production. However, the mechanisms involved and, in particular, the role of the different thyroid hormone receptors in lymphocyte development have not been investigated. To address that question, we have studied lymphocyte development in mice deficient for the T3R alpha 1 and T3R alpha 2 gene products. A strong decrease in spleen cell numbers was found compared with wild-type littermates, B lymphocytes being more severely affected than T lymphocytes. A significant decrease in splenic macrophage and granulocyte numbers was also found. In bone marrow, a reduction in CD45+/IgM- pro/pre-B cell numbers was found in these mice compared with wild-type littermates. This decrease seems to result from a proliferation defect, as CD45+/IgM- cells incorporate less 5-bromo-2'-deoxyuridine in vivo. To define the origin of the bone marrow development defect, chimeric animals between T3R alpha-/- and Rag1-/- mice were generated. Results indicate that for B cells the control of the population size by T3R alpha 1 and T3R alpha 2 is intrinsic. Altogether, these results show that T3R alpha 1 or T3R alpha 2 gene products are implicated in the control of the B cell pool size.

GLOB-1: a prospective randomised clinical phase III trial comparing vinorelbine-cisplatin with vinorelbine-ifosfamide-cisplatin in metastatic non-small-cell lung cancer patients

BACKGROUND

The standard doublet, vinorelbine-cisplatin, was compared with a triplet of vinorelbine-ifosfamide-cisplatin, in terms of survival, in patients with advanced non-small-cell lung cancer (NSCLC).

PATIENTS AND METHODS

From February 1998 to June 1999, 259 chemonaïve patients entered the study and were randomised to receive either vinorelbine-cisplatin (NP; vinorelbine 30 mg/m(2) on days 1, 8 and 15 with cisplatin 80 mg/m(2) on day 1) or vinorelbine-ifosfamide-cisplatin (NIP; vinorelbine 25 mg/m(2) on days 1 and 8, ifosfamide 3 g/m(2) on day 1 and cisplatin 75 mg/m(2) on day 1), with both regimens being repeated every 3 weeks. All patients had stage IV or relapsed disease and a performance score of 0 or 1.

RESULTS

The overall response rate was 34.6% for NP and 35.7% for NIP. Median and 1-year survival rates were 10.0 months and 38.4% for NP, and 8.2 months and 33.7% for NIP, respectively. A median of four cycles was administered in each arm. The major World Health Organization grade 3-4 toxicities for NP and NIP, respectively, were: neutropenia (20.3% compared with 9% of cycles), anaemia (4.1% compared with 5% of cycles), nausea and vomiting (22.2% compared with 19.4% of patients) and alopecia (5.6% compared with 29.8% of patients). Four toxic deaths occurred in the NP arm and eight in the NIP arm.

CONCLUSIONS

The different schedules of vinorelbine in the two arms led to a greater survival in the NP arm without impairing the tolerance profile, although this is not statistically significant. This confirms that the two-drug combination NP is a reference treatment for metastatic NSCLC. The role of three-drug combinations remains questionable in this subset of patients.

Quality of response in different population groups in mail and telephone surveys

Mail and telephone survey methods, with follow-up by other methods, can provide high response rates. However, it is not clear whether different population groups provide responses of different quality, thus creating risk of biased comparisons. A closely related problem is whether proxy response adequately substitutes for self-response. This study addressed these issues in the context of parallel mail and telephone health surveys carried out in Montreal. In the telephone survey, proxy respondents provided lower estimates of morbidity and health care utilization than self-respondents; in the mail survey, there was no difference between proxy and self-response. Response validity was assessed by comparing reported physician visits with those recorded by the government-run universal health insurance plan. In general, mail responses were more valid than telephone responses. In both methods, there were suggestive but not persuasive differences in validity among sociodemographic subgroups. In both methods, those reporting illness or medication use had less underreporting of physician visits than those not reporting such things.

EMF1, a novel protein involved in the control of shoot architecture and flowering in Arabidopsis

Shoot architecture and flowering time in angiosperms depend on the balanced expression of a large number of flowering time and flower meristem identity genes. Loss-of-function mutations in the Arabidopsis EMBRYONIC FLOWER (EMF) genes cause Arabidopsis to eliminate rosette shoot growth and transform the apical meristem from indeterminate to determinate growth by producing a single terminal flower on all nodes. We have identified the EMF1 gene by positional cloning. The deduced polypeptide has no homology with any protein of known function except a putative protein in the rice genome with which EMF1 shares common motifs that include nuclear localization signals, P-loop, and LXXLL elements. Alteration of EMF1 expression in transgenic plants caused progressive changes in flowering time, shoot determinacy, and inflorescence architecture. EMF1 and its related sequence may belong to a new class of proteins that function as transcriptional regulators of phase transition during shoot development.