Measurement of the Gerasimov-Drell-Hearn Integrand for 2H from 200 to 800 MeV

A measurement of the helicity dependence of the total inclusive photoabsorption cross section on the deuteron was carried out at MAMI (Mainz) in the energy range 200<Egamma<800 MeV. The experiment used a 4pi detection system, a circularly polarized tagged photon beam and a frozen-spin target which provided longitudinally polarized deuterons. The contribution to the Gerasimov-Drell-Hearn sum rule for the deuteron determined from the data is 407+/-20(stat)+/-24(syst) mu b for 200<Egamma<800 MeV.

BCR-ABL1 induces aberrant splicing of IKAROS and lineage infidelity in pre-B lymphoblastic leukemia cells

Pre-B lymphoblastic leukemia cells carrying a BCR-ABL1 gene rearrangement exhibit an undifferentiated phenotype. Comparing the genome-wide gene expression profiles of normal B-cell subsets and BCR-ABL1+ pre-B lymphoblastic leukemia cells by SAGE, the leukemia cells show loss of B lymphoid identity and aberrant expression of myeloid lineage-specific molecules. Consistent with this, BCR-ABL1+ pre-B lymphoblastic leukemia cells exhibit defective expression of IKAROS, a transcription factor needed for early lymphoid lineage commitment. As shown by inducible expression of BCR-ABL1 in human and murine B-cell precursor cell lines, BCR-ABL1 induces the expression of a dominant-negative IKAROS splice variant, termed IK6. Comparing matched leukemia sample pairs from patients before and during therapy with the BCR-ABL1 kinase inhibitor STI571 (Imatinib), inhibition of BCR-ABL1 partially corrected aberrant expression of IK6 and lineage infidelity of the leukemia cells. To elucidate the contribution of IK6 to lineage infidelity in BCR-ABL1+ cell lines, IK6 expression was silenced by RNA interference. Upon inhibition of IK6, BCR-ABL1+ leukemia cells partially restored B lymphoid lineage commitment. Therefore, we propose that BCR-ABL1 induces aberrant splicing of IKAROS, which interferes with lineage identity and differentiation of pre-B lymphoblastic leukemia cells.

First measurement of the transverse spin asymmetries of the deuteron in semi-inclusive deep inelastic scattering

First measurements of the Collins and Sivers asymmetries of charged hadrons produced in deep-inelastic scattering of muons on a transversely polarized 6LiD target are presented. The data were taken in 2002 with the COMPASS spectrometer using the muon beam of the CERN SPS at 160 GeV/c. The Collins asymmetry turns out to be compatible with zero, as does the measured Sivers asymmetry within the present statistical errors.

Measurement of helicity-dependent photoabsorption cross sections on the neutron from 815 to 1825 MeV

Helicity-dependent total photoabsorption cross sections on the deuteron have been measured for the first time at ELSA (Bonn) in the photon energy range from 815 to 1825 MeV. Circularly polarized tagged photons impinging on a longitudinally polarized LiD target have been used together with a highly efficient 4pi detector system. The data around 1 GeV are not compatible with predictions from existing multipole analyses. From the measured energy range an experimental contribution to the GDH integral on the neutron of [33.9 +/- 5.5(stat) +/- 4.5(syst)] microb is extracted.

Photoproduction of eta mesons off protons for 0.75 GeV<E(gamma)<3 GeV

Total and differential cross sections for the reaction p(gamma,eta)p have been measured for photon energies in the range from 750 MeV to 3 GeV. The low-energy data are dominated by the S11 wave which has two poles in the energy region below 2 GeV. Eleven nucleon resonances are observed in their decay into peta. At medium energies we find evidence for a new resonance N(2070)D15 with (M,Gamma)=(2068+/-22, 295+/-40) MeV. At gamma energies above 1.5 GeV, a strong peak in the forward direction develops, signaling the exchange of vector mesons in the t channel.

Neutral-pion photoproduction off protons in the energy range 0.3 GeV<E(gamma)<3 GeV

Single pi(0) photoproduction has been studied with the CB-ELSA experiment at Bonn using tagged photon energies between 0.3 and 3.0 GeV. The experimental setup covers a very large solid angle of approximately 98% of 4pi. Differential cross sections dsigma/dOmega have been measured. Complicated structures in the angular distributions indicate a variety of different resonances being produced in the s channel intermediate state gammap-->N(*)(Delta(*))-->ppi(0). A combined analysis including the data presented in this letter along with other data sets reveals contributions from known resonances and evidence for a new resonance N(2070)D15.

Experimental check of the Gerasimov-Drell-Hearn sum rule for 1H

For the first time we checked the fundamental Gerasimov-Drell-Hearn (GDH) sum rule for the proton experimentally in the photon energy range from 0.2-2.9 GeV with the tagged photon facilities at MAMI (Mainz) and ELSA (Bonn). New data of the doubly polarized total cross section difference are presented in the energy range from 1.6 to 2.9 GeV. The contribution to the GDH integral from 0.2-2.9 GeV yields [254+/-5(stat)+/-12(syst)] microb with negative contributions in the Regge regime at photon energies above 2.1 GeV. This trend supports the validity of the GDH sum rule.

Lung transplant at the Favaloro Foundation: A 13-year experience

BACKGROUND

The outcomes of lung transplantation (LT) are well known in developed countries, but not in Latin America. Our objective was to report the LT experience at a single center in Argentina.

METHODS

From June 1994 to February 2003, the 54 LT that were performed included 36 single-lung transplants SLT (45.5%) and 18 double-lung transplants (DSLT) (22.7%). Indications for SLT (n = 36) were emphysema (n = 23) and pulmonary fibrosis (n = 13); for DSLT (n = 18), bronchiectasis (n = 8), cystic fibrosis (n = 8), pulmonary emphysema (n = 1), and bronchiolitis obliterans syndrome caused by graft-versus-host disease after bone-marrow transplantation (n = 1). A univariate analysis, chi-square test with Yates' correction was used for qualitative variables; Wilcoxon-Mann-Whitney test, for quantitative and ordinal variables. Survivals were estimated by the Kaplan-Meier method.

RESULTS

In-hospital mortality (HM) was 21.1%. Among SLT, early death was due to sepsis in six patients and by ischemia-reperfusion injury (IRI) and acute rejection in other two. In DSLT, two patients died due to IRI and one, sepsis. The overall estimated survival rates at 1, 2, and 4 years were 70.1% +/- 6.5%, 54.3% +/- 7.2%, and 44.3% +/- 7.9%, respectively. The median overall survival was 26.5 (10 to 34) months. When HM was excluded, survival at 4 years was 51.3% +/- 8.7%. The estimated survival at 3 years was 43.3% +/- 9.3% for SLT and 58.7% +/- 13% for DSLT (P = 6). Survival differences according to the baseline diagnosis were not significant (P =.6). Median follow-up time (percentiles 25 to 75) was 16 (2 to 27) months.

CONCLUSIONS

Our LT program shows similar results to those reported by the International Society for Heart and Lung Transplantation for developed countries.

Orthotopic heart transplantation in elderly patients: A 10-year experience at a single center

INTRODUCTION

A consensus has not yet been reached regarding the indications for orthotopic heart transplantation (OHT) in elderly patients or the age limit contraindicating the procedure. The objective of this study was to assess OHT outcomes to determine whether elderly patients benefit from the procedure.

METHODS

From February 1993 to February 2003, 178 OHTs were performed on recipients of mean age 47.4 +/- 15 years (range, 4 to 74) including 80.3% men. The population was divided into two groups: group A included patients >/= 60 years, and group B those younger than that age. Survival was analyzed for the overall population and for both age groups during a 10-year follow-up period.

RESULTS

Group A included 36 patients (20.8%) and group B 142 patients (79.2%). Mean age was 63.7 +/- 2.9 years (60 to 74) in A, and 43 +/- 13.9 years (4 to 59) in B. In-hospital mortality was significantly higher among group A (n = 11, 31.4%) compared to B (n = 17, 12.1%, P =.008). Survival at 1, 5, and 10 years was 61.5% +/- 8%, 58.1% +/- 8.3%, and 49.8% +/- 10.5% group A; and 84.2% +/- 3%, 73.7% +/- 4.1%, and 69.9% +/- 4.7 for group B. Elderly patients showed a lower survival rate (49.8%) compared with the younger group (69.9%) at 10-year follow-up (P =.007). Conditional survival at 9 years failed to show significant differences (A 72.2% vs B 79.6%, P =.4).

CONCLUSION

In our population, elderly recipients showed a higher in-hospital mortality. However, when the first post-OHT year was excluded, we found similar survival rates for both age groups.

Wildlife genetics and disease: allozyme evolution in the wild boar (Sus scrofa) caused by a swine fever epidemy

Enzyme polymorphism at 42 loci was compared before and after a major epidemy of swine fever in wild boars from northern Vosges (France). No change was observed in the 38 monomorphic loci, but allele frequencies at the phosphoglucomutase locus PGM-2* changed significantly. Possible causes for this observation are discussed, and it appears that PGM-2 locus could be a genetic marker of resistance to this viral disease.

GermOnline, a cross-species community knowledgebase on germ cell differentiation

GermOnline provides information and microarray expression data for genes involved in mitosis and meiosis, gamete formation and germ line development across species. The database has been developed, and is being curated and updated, by life scientists in cooperation with bioinformaticists. Information is contributed through an online form using free text, images and the controlled vocabulary developed by the GeneOntology Consortium. Authors provide up to three references in support of their contribution. The database is governed by an international board of scientists to ensure a standardized data format and the highest quality of GermOnline's information content. Release 2.0 provides exclusive access to microarray expression data from Saccharomyces cerevisiae and Rattus norvegicus, as well as curated information on approximately 700 genes from various organisms. The locus report pages include links to external databases that contain relevant annotation, microarray expression and proteome data. Conversely, the Saccharomyces Genome Database (SGD), S.cerevisiae GeneDB and Swiss-Prot link to the budding yeast section of GermOnline from their respective locus pages. GermOnline, a fully operational prototype subject-oriented knowledgebase designed for community annotation and array data visualization, is accessible at http://www.germonline.org. The target audience includes researchers who work on mitotic cell division, meiosis, gametogenesis, germ line development, human reproductive health and comparative genomics.

First Measurement of the Gerasimov-Drell-Hearn Sum Rule for 1H from 0.7 to 1.8 GeV at ELSA

To verify the fundamental Gerasimov-Drell-Hearn (GDH) sum rule for the first time experimentally, we measured the helicity dependent total photoabsorption cross section with circularly polarized real photons and longitudinally polarized nucleons in the photon energy range 0.68-1.82 GeV with the tagged photon facility at ELSA. The experiment was carried out with a 4pi detection system, a circularly polarized tagged photon beam, and a frozen spin polarized proton target. The contribution to the GDH sum rule in this photon energy range is [49.9+/-2.4(stat)+/-2.2(syst)] microb.

Cardiovascular and respiratory consequences of bilateral involvement of the medullary intermediate reticular formation in syringobulbia

We studied five patients with clinical and radiological evidence of syringobulbia (SB) to determine whether the distribution of lesions in relationship to the cardiorespiratory control networks in the medullary intermediate reticular zone (IRt) correlates with the presence of abnormalities in autonomic cardiovascular and respiratory control in these patients. All patients underwent high resolution MRI to characterize the size, volume and distribution of the SB lesions, cardiovascular autonomic function testing and polysomnography. One patient with bilateral IRt involvement at both the rostral and caudal medulla had orthostatic hypotension (OH), absent HR(DB), abnormal Valsalva ratio, exaggerated fall of BP during phase II and absent phase IV during VM, and a dramatic fall of BP during head up tilt; this patient also had severe obstructive sleep apnea (OSA) and exhibited BP drops during each respiratory effort. A second patient, with bilateral IRt involvement restricted to the caudal medulla, had less severe cardiovascular autonomic dysfunction but also exhibited severe OSA. The other three patients had small SB cavities sparing the IRt and had sleep apnea but no autonomic dysfunction. Autonomic dysfunction could not be related to the size of the syrinx or the degree of atrophy in the cervical spinal cord in any of the five patients. Bilateral involvement of the IRt by SB produces cardiovascular autonomic failure and sleep apnea. In patients with more restricted lesions, autonomic and respiratory dysfunction may be dissociated. Clinico-radiological correlations using high resolution MRI assessment of medullary lesions can provide insight into the central organization of cardiovascular and respiratory control in humans.

Helicity amplitudes A1/2 and A3/2 for the D13(1520) resonance obtained from the gamma-->p-->-->ppi(0) Reaction

The helicity dependence of the gamma-->p-->-->ppi(0) reaction has been measured for the first time in the photon-energy range from 550 to 790 MeV. The experiment, performed at the Mainz microtron MAMI, used a 4pi-detector system, a circularly polarized, tagged photon beam, and a longitudinally polarized frozen-spin target. These data are predominantly sensitive to the D13(1520) resonance and are used to determine its helicity amplitudes.

[Comparative analysis of the sensitivity and accuracy of clinical, radiographic and histometric measurements in assessing periodontal attachment levels]

The ultimate goal of the regenerative periodontal treatment is the de novo formation of new connective tissue attachment with the regrowth of the alveolar bone. Clinically it is very difficult to evaluate the nature of clinical healing and prove the occurrence of real periodontal regeneration. The aim of the present study was to compare the clinical and radiographic parameters with the histometric findings following two different periodontal regenerative procedures in humans.

Measurement of the beam-helicity asymmetry in the p((-->)e,e'p)pi(0) reaction at the energy of the Delta(1232) resonance

In a p((-->)e,e'p)pi(0) out-of-plane coincidence experiment at the three-spectrometer setup of the Mainz Microtron MAMI, the beam-helicity asymmetry has been precisely measured around the energy of the Delta(1232) resonance and Q(2) = 0.2(GeV/c)(2). The results are in disagreement with three up-to-date model calculations. This is interpreted as a lack of understanding of the nonresonant background, which in dynamical models is related to the pion cloud.

Radiographic defect depth and width for prognosis and description of periodontal healing of infrabony defects

BACKGROUND

The aims of the present study were to evaluate 1) defect depth and width as a prognostic factor and 2) change in defect width as a describing parameter of periodontal healing in infrabony defects treated by regenerative therapy after 6 and 24 months.

METHODS

In 24 patients with advanced periodontitis, 39 infrabony defects were treated by guided tissue regeneration (GTR) using expanded polytetrafluoroethylene (ePTFE) (n = 7) or bioabsorbable barriers (n = 32). Clinical parameters were assessed and 39 standardized radiographs (in triplicate) were taken before and 6 and 24 months after surgery. Using a computer-assisted analysis, the depth, width, and angle of the bony defects were measured.

RESULTS

Statistically significant vertical clinical attachment gains (CAL-V: 3.15 +/- 1.63 mm to 3.31 +/- 1.65 mm; P<0.001) and bony fill (1.30 +/- 2.53 mm; P<0.01 to 1.54 +/- 2.70 mm; P<0.005) were observed 6 and 24 months postsurgically. In a multilevel regression analysis CAL-V gain was predicted by baseline CAL-V (P <0.0001), actual smoking (P <0.05), and age (P <0.1). Bony fill could be predicted by baseline height of the infrabony component (P<0.0001), gingival index at baseline (P<0.05), and actual smoking (P <0.01). In narrow (<26 degrees) and deep (> or = 3 mm) infrabony defects bony fill was more pronounced than in wide and shallow defects (P <0.05).

CONCLUSIONS

Improvement achieved by guided tissue regeneration in infrabony defects can be maintained up to 24 months after surgery. Narrow and deep infrabony defects respond radiographically and to some extent clinically more favorably to GTR therapy than wide and shallow defects. However, depth of the infrabony component was a stronger prognostic parameter than defect angle. Actual smoking impairs the results of GTR therapy in infrabony defects.

[Mycotic aneurysms--A retrospective analysis]

12 patients (10 males and 2 females, average age 53 years) were operated upon in our hospital between 1994 and 1999 for mycotic aneurysms. The aneurysms were located in 7 patients in the aorto-iliac segment, 5 patients were treated for peripheral or visceral aneurysms. Two of these patients suffered from multiple aneurysms. When peripheral arteries were affected, a pulsatile tumour was felt. Most of these tumours developed in a relatively short period of time and sometimes a perivascular inflammation occurred. This was not the case when central arteries were attacked. A septic process or an infection, for example salmonella-enteritis, often preceded shortly the development of a mycotic aneurysm. In the case of an aneurysm of the aorto-iliac section we consider an in situ reconstruction with alloplastic material in combination with a perivascular debridement, lavage and omentum majus plastic as the treatment of choice. In peripheral arteries reconstruction should be performed with autologous vessels. Depending on the local findings, a perivascular debridement should also be performed in these cases. The reconstruction always should be combined with a calculated antibiotic therapy. Two of our patients died perioperatively. During follow up, 8 patients showed patent reconstructions and no signs of infection. The urgency of surgery depends on the level of inflammation and the existence of any secondary complications.

Demonstration of heterogeneous genotypes of Taylorella equigenitalis isolated from horses in six European countries by pulsed-field gel electrophoresis

Forty-six isolates of Taylorella equigenitalis were analysed by pulsed-field gel electrophoresis (PFGE) after separate digestion of the genomic DNA with ApaI and with NotI. The isolates had been obtained from horses in six European countries and were classified into 18 genotypes. In Belgium, 2 genotypes were detected in 2 isolates, in England 9 among 15, in Finland 2 in 2, in France 2 among 10, in Sweden 3 among 5, and in Switzerland 3 among 12. Two English isolates and 4 French isolates gave identical PFGE profiles to those of Kentucky 188 from the United States. A common genotype was found in 5 isolates from Belgium and England and also in 10 isolates from France and Switzerland. The analysis of genomic DNA from 12 isolates of T equigenitalis obtained from male horses in France, Sweden and Switzerland gave no evidence of a sex-related difference in the genomic DNA. Genomic DNA from 11 streptomycin (STM)-susceptible isolates obtained in Sweden and Switzerland were classified into four genotypes by PFGE. Each of the six genotypes determined among the 17 isolates from these two countries had single phenotypes for resistance or susceptibility to STM.

A screen for genes required for meiosis and spore formation based on whole-genome expression

BACKGROUND

Meiosis is the process by which gametes are generated with half the ploidy of somatic cells. This reduction is achieved by three major differences in chromosome behavior during meiosis as compared to mitosis: the production of chiasmata by recombination, the protection of centromere-proximal sister chromatid cohesion, and the monoorientation of sister kinetochores during meiosis I. Mistakes in any of these processes lead to chromosome missegregation.

RESULTS

To identify genes involved in meiotic chromosome behavior in Saccharomyces cerevisiae, we deleted 301 open reading frames (ORFs) which are preferentially expressed in meiotic cells according to microarray gene expression data. To facilitate the detection of chromosome missegregation mutants, chromosome V of the parental strain was marked by GFP. Thirty-three ORFs were required for the formation of wild-type asci, eight of which were needed for proper chromosome segregation. One of these (MAM1) is essential for the monoorientation of sister kinetochores during meiosis I. Two genes (MND1 and MND2) are implicated in the recombination process and another two (SMA1 and SMA2) in prospore membrane formation.

CONCLUSIONS

Reverse genetics using gene expression data is an effective method for identifying new genes involved in specific cellular processes.

Measurement of the recoil polarization in the p(e-->, e'p-->)pi(0) reaction at the Delta(1232) resonance

The recoil proton polarization has been measured in the p(e-->,e'p-->)pi(0) reaction in parallel kinematics around W = 1232 MeV, Q2 = 0.121 (GeV/c)2, and epsilon = 0.718 using the polarized cw electron beam of the Mainz Microtron. All three proton polarization components, Px/P(e) = (-11.4+/-1.3+/-1.4)%, P(y) = (-43.1+/-1.3+/-2.2)%, and P(z)/P(e) = (56.2+/-1.5+/-2.6)%, could be measured simultaneously. The Coulomb quadrupole to magnetic dipole ratio, CMR = (-6.4+/-0.7(stat)+/-0.8(syst))%, was determined from Px in the framework of the Mainz Unitary Isobar Model. The consistency among the reduced polarizations and the extraction of the ratio of longitudinal-to-transverse response is discussed.

Building a Web-based drug ordering system for hospitals: from requirements engineering to prototyping

Web-based drug ordering allows a growing number of hospitals without pharmacy to communicate seamlessly with their external pharmacy. Business process analysis and object oriented modelling performed together with the users at a pilot hospital resulted in a comprehensive picture of the user and business requirements for electronic drug ordering. The user requirements were further validated with the help of a software prototype. In order to capture the needs of a large number of users CAP10, a new method making use of pre-built models, is proposed. Solutions for coping with the technical requirements (interfacing the business software at the pharmacy) and with the legal requirements (signing the orders) are presented.

B-type cyclins CLB5 and CLB6 control the initiation of recombination and synaptonemal complex formation in yeast meiosis

BACKGROUND

The life cycle of most eukaryotic organisms includes a meiotic phase, in which diploid parental cells produce haploid gametes. During meiosis a single round of DNA replication is followed by two rounds of chromosome segregation. In the first, or reductional, division (meiosis I), which is unique to meiotic cells, homologous chromosomes segregate from one another, whereas in the second, or equational, division (Meiosis II) sister centromeres disjoin. Meiotic DNA replication precedes the initiation of recombination by programmed Spo11-dependent DNA double-strand breaks. Recent reports that meiosis-specific cohesion is established during meiotic S phase and that the length of S phase is modified by recombination factors (Spo11 and Rec8) raise the possibility that replication plays a fundamental role in the recombination process.

RESULTS

To address how replication influences the initiation of recombination, we have used mutations in the B-type cyclin genes CLB5 and CLB6, which specifically prevent premeiotic replication in the yeast Saccharomyces cerevisiae. We find that clb5 and clb5 clb6 but not clb6 mutants are defective in DSB induction and prior associated changes in chromatin accessibility, heteroallelic recombination, and SC formation. The severity of these phenotypes in each mutant reflects the extent of replication impairment.

CONCLUSIONS

This assemblage of phenotypes reveals roles for CLB5 and CLB6 not only in DNA replication but also in other key events of meiotic prophase. Links between the function of CLB5 and CLB6 in activating meiotic DNA replication and their effects on subsequent events are discussed.

HO endonuclease-induced recombination in yeast meiosis resembles Spo11-induced events

In meiosis, gene conversions are accompanied by higher levels of crossing over than in mitotic cells. To determine whether the special properties of meiotic recombination can be attributed to the way in which Spo11p creates double-strand breaks (DSBs) at special hot spots in Saccharomyces cerevisiae, we expressed the site-specific HO endonuclease in meiotic cells. We could therefore compare HO-induced recombination in a well-defined region both in mitosis and meiosis, as well as compare Spo11p- and HO-induced meiotic events. HO-induced gene conversions in meiosis were accompanied by crossovers at the same high level (52%) as Spo11p-induced events. Moreover, HO-induced crossovers were reduced 3-fold by a msh4Delta mutation that similarly affects Spo11p-promoted events. In a spo11Delta diploid, where the only DSB is made by HO, crossing over was significantly higher (27%) than in mitotic cells (</=7%). This single meiotic DSB failed to induce the formation of a synaptonemal complex. We also show that HO-induced gene conversion tract lengths are shorter in meiotic than in mitotic cells. We conclude that a hallmark of meiotic recombination, the production of crossovers, is independent of the nature of Spo11p-generated DSBs at special hotspots, but some functions of Spo11p are required in trans to achieve maximum crossing over.

Identification of high affinity Tbf1p-binding sites within the budding yeast genome

The yeast TBF1 gene is essential for mitotic growth and encodes a protein that binds the human telomere repeats in vitro, although its cellular function is unknown. The sequence of the DNA-binding domain of Tbf1p is more closely related to that of the human telomeric proteins TRF1 and TRF2 than to any yeast protein sequence, yet the functional homologue of TRF1 and TRF2 is thought to be Rap1p. In this study we show that the Tbf1p DNA-binding domain can target the Gal4 transactivation domain to a (TTAGGG)(n) sequence inserted in the yeast genome, supporting the model that Tbf1p binds this sub-telomeric repeat motif in vivo. Immunofluorescence of Tbf1p shows a spotty pattern throughout the interphase nucleus and along synapsed chromosomes in meiosis, suggesting that Tbf1p binds internal chromosomal sites in addition to sub-telomeric regions. PCR-assisted binding site selection was used to define a consensus for high affinity Tbf1p-binding sites. Compilation of 50 selected oligonucleotides identified the consensus TAGGGTTGG. Five potential Tbf1p-binding sites resulting from a search of the total yeast genome were tested directly in gel shift assays and shown to bind Tbf1p efficiently in vitro, thus confirming this as a valid consensus for Tbf1p recognition.

Helicity dependence of gammap --> Npi below 450 MeV and contribution to the Gerasimov-Drell-Hearn sum rule

The helicity dependence of the single pion photoproduction on the proton has been measured in the energy range from 200 to 450 MeV for the first time. The experiment, performed at the Mainz microtron MAMI, used a 4pi-detector system, a circularly polarized, tagged photon beam, and a frozen-spin target. The data obtained provide new information for multipole analyses of pion photoproduction and determine the main contributions to the Gerasimov-Drell-Hearn sum rule and the forward spin polarizability gamma(0).

Electron paramagnetic resonance for everybody--MICROspec-X--a new class of electron paramagnetic resonance spectrometer

The electron paramagnetic resonance spectroscopy is the only method for detecting free radicals. Free radicals have an increased importance in our daily life. A small transportable EPR spectrometer is presented for the popularisation of the EPR method. The technical construction and some applications are illustrated which show the usability of the spectrometer.

Quantitative karyotyping and dual-color FISH mapping of 5S and 18S-25S rDNA probes in the cultivated Phaseolus species (Leguminosae)

Double-color fluorescence in situ hybridization (FISH) followed by DAPI counterstaining allowed the chromosomal assignment of 5S and 18S-25S rRNA genes in the four cultivated Phaseolus Species; P. vulgaris, P. coccineus, P. acutifolius, and P. lunatus (all: 2n = 2x = 22). The rRNA gene loci display variation between species as reflected in differences of signal size and (or) number. From one to three pairs of 5S sites and one to seven pairs of 18S-25S sites were found in the diploid complements of the four taxa studied. Intraspecific variation was studied in P. vulgaris, and it is shown that the number of 18S-25S rDNA sites differs between cultivars. Cytogenetic mapping was complemented by karyotype analyses. Each of the four cultivated Phaseolus species exhibits a characteristic heterochromatin endowment, with P. acutifolius var. latifolius having the highest amount of C-band material. Quantitative karyotyping in combination with cytogenetic mapping allowed the identification of homeologous chromosomes in the different species.

Estimation of Neospora caninum seroprevalence in dairy cattle from Normandy, France

An epidemiological study was conducted in Orne (France) on randomly selected dairy herds (42 herds including 1,924 cows and heifers, which were at least 15 months old). The aim was primarily to estimate the seroprevalence of Neospora caninum infection from two blood samples per cow, using an enzyme-linked immunosorbent assay (ELISA) for N. caninum (one positive result indicating infection). The second aim was to test the association between some individual and herd factors and N. caninum seropositivity with a logistic model including a random term effect. The prevalence was estimated at 5.6% (107 seropositive animals). At least 27 of the 42 herds had one seropositive cow or heifer. The intra-herd seroprevalence varied from 1.1 to 8% for 18 positive herds (66.7%). Dogs were present in 36 farms and 104 of the 107 seropositive animals were exposed to them. The factors associated with individual seropositivity were the presence of cats (OR = 0.17; P < 0.001), dogs (OR = 4.35; P = 0.02), rabbits and/or ducks (OR = 2.10; P = 0.04), long calving periods (12 months) (OR = 0.44; P = 0.007), tethered housing (OR = 2.50; P = 0.01), somatic cell counts (200-400 x 10(3) cells/mL) (OR = 0.24; P < 0.001) and pond water supply (OR = 2.43; P = 0.04). In conclusion, the animal and intra-herd seroprevalences were low in dairy cows from Normandy, France.

A central role for cohesins in sister chromatid cohesion, formation of axial elements, and recombination during yeast meiosis

A multisubunit complex, called cohesin, containing Smc1p, Smc3p, Scc1p, and Scc3p, is required for sister chromatid cohesion in mitotic cells. We show here that Smc3p and a meiotic version of Scc1p called Rec8p are required for cohesion between sister chromatids, for formation of axial elements, for reciprocal recombination, and for preventing hyperresection of double-strand breaks during meiosis. Both Rec8p and Smc3p colocalize with chromosome cores independently of synapsis during prophase I and largely disappear from chromosome arms after pachytene but persist in the neighborhood of centromeres until the onset of anaphase II. The eukaryotic cell's cohesion apparatus is required both for the repair of recombinogenic lesions and for chromosome segregation and therefore appears to lie at the heart of the meiotic process.

YDL142c encodes cardiolipin synthase (Cls1p) and is non-essential for aerobic growth of Saccharomyces cerevisiae

The unassigned open reading frame YDL142c was identified to code for cardiolipin synthase, Cls1p. A cls1 deletion strain is viable on glucose, galactose, ethanol, glycerol and lactate containing media, although the growth rate on non-fermentable carbon sources is decreased. Mitochondria of the cls1 mutant are devoid of cardiolipin but accumulate the cardiolipin precursor phosphatidylglycerol when grown on non-fermentable carbon sources. Specific activity of phosphatidylglycerolphosphate synthase in cls1 is reduced to 30-75% of the wild-type level. Amounts of mitochondrial cytochromes and activity of cytochrome c oxidase, however, are not affected in the cls1 deletion strain. Collectively, these data indicate that cardiolipin is not essential for aerobic growth of Saccharomyces cerevisiae.

mre11S--a yeast mutation that blocks double-strand-break processing and permits nonhomologous synapsis in meiosis

During meiotic prophase the repair of self-inflicted DNA double-strand break (DSB) damage leads to meiotic recombination in yeast. We employed a genetic screen to specifically characterize cellular functions that become essential after this DSB formation. As a result a new allele of MRE11, termed mre11S (for Separation of functions) was isolated that allows initiation but not processing and repair of meiotic DSBs similar to the well-characterized rad50S allele. In contrast, the mre11-1 allele blocks initiation of meiotic DSBs as reported previously by others. The mre11S allele, which is mutated in the 5' part of the gene, can partially complement mre11 alleles disrupted close to the 3' end that cannot initiate DSBs when homozygous. This suggests homodimerization of the Mre11 protein and the presence of separate domains for DSB initiation and 5' resection. The fact that two genes, RAD50 and MRE11, required for DSB processing are also essential for DSB initiation dictates a model in which a bifunctional initiation/repair complex is required to initiate meiotic recombination. A subset of mre11S nuclei was shown to perform extensive but partially nonhomologous synapsis. We propose that the unprocessed DSBs present in mre11S allow for synapsis, but that homologous synapsis is only ensured at a later stage of recombination.

[Transesophageal ultrasound for staging lung tumors]

PURPOSE

The usefulness of transesophageal sonography in staging lung cancer was examined.

METHOD

Transoesophageal sonography was performed in 15 patients as a staging examination using either biplane or multiplane technique. The results were compared with other radiological techniques such as computed tomography and, if performed, with the findings in the operation.

RESULTS

The neoplastic mass was correctly identified in 12 of the 15 patients. Transoesophageal sonography is a very useful examination, more so than computed tomography, for identification of a tumour infiltration into great vessels or cardiovascular structures. In 8 cases we found paraaortal tumour masses and in 4 cases infiltration of the pulmonary artery. In 2 cases we could show an infiltration of heart chambers. The sensitivity for detecting lymph nodes was 80% in the lower mediastinum and, because of method limitations, only 33% in the upper mediastinum.

CONCLUSION

Transoesophageal sonography is an excellent addition to the already well established staging methods in staging lung cancer. This examination clearly has advantages over the conventional methods (CT scan) for the diagnosis of vessel involvement, extrinsic compression of the heart, and for the recognition of lymph node metastases. The limitation of this examination is the restriction to the paraoesophageal area and reduced effectiveness in areas filled with air and other nonconductive structures.

Isolation of COM1, a new gene required to complete meiotic double-strand break-induced recombination in Saccharomyces cerevisiae

We have designed a screen to isolate mutants defective during a specific part of meiotic prophase I of the yeast Saccharomyces cerevisiae. Genes required for the repair of meiotic double-strand breaks or for the separation of recombined chromosomes are targets of this mutant hunt. The specificity is achieved by selecting for mutants that produce viable spores when recombination and reductional segregation are prevented by mutations in SPO11 and SPO13 genes, but fail to yield viable spores during a normal Rec+ meiosis. We have identified and characterized a mutation com1-1, which blocks processing of meiotic double-strand breaks and which interferes with synaptonemal complex formation, homologous pairing and, as a consequence, spore viability after induction of meiotic recombination. The COM1/SAE2 gene was cloned by complementation, and the deletion mutant has a phenotype similar to com1-1, com1/sae2 mutants closely resemble the phenotype of rad50S, as assayed by phase-contrast microscopy for spore formation, physical and genetic analysis of recombination, fluorescence in situ hybridization to quantify homologous pairing and immunofluorescence and electron microscopy to determine the capability to synapse axial elements.

Elevated ambulatory blood pressure in microalbuminuric IDDM patients is inversely associated with renal plasma flow. A compensatory mechanism?

OBJECTIVE

To evaluate the relationship between renal function, ambulatory blood pressure (AMBP), and glycemic control in microalbuminuric IDDM patients compared with normoalbuminuric patients.

RESEARCH DESIGN AND METHODS

Nineteen male patients (age 33 +/- 6 years) with slight microalbuminuria (UAE 20-70 micrograms/min) were compared with 19 normoalbuminuric (UAE < 15 micrograms/min) age-matched (33 +/- 6 years) male patients. Through constant infusion technique, 125I-iothalamate marked the glomerular filtration rate (GFR), and 131I-hippuran marked effective renal plasma flow (RPF). AMBP was measured by oscillometric technique (Spacelabs 90202).

RESULTS

The microalbuminuric group had higher daytime systolic AMBP (132 +/- 11 vs. 125 +/- 7 mmHg, P < 0.05) and a poorer glycemic control (HbA1c 9.5 +/- 1.5 vs. 8.2 +/- 1.3%, P < 0.01). GFR (135 +/- 22 and 135 +/- 17 ml/min) and RPF (598 +/- 112 and 542 +/- 98 ml/min) were similar in the two groups. In the microalbuminuric group, daytime systolic AMBP was inversely correlated to both RPF (r = -0.77, P < 0.005) and GFR (r = -0.53, P = 0.02). HbA1c and GFR correlated positively in the microalbuminuric group (r = 0.47, P < 0.04). In contrast, the normoalbuminuric patients exhibited no such associations.

CONCLUSIONS

IDDM patients with moderate microalbuminuria have elevated AMBP and a strong negative association between AMBP and RPF. This leaves several possibilities of interpretation. Primary blood pressure increase (of unknown origin) may induce morphological changes leading to reduction in renal function. Alternatively, blood pressure increase early in the course of incipient nephropathy may represent a compensatory mechanism, initially aiming at preservation of renal function, but later becoming maladaptive.

Production and characterization of monoclonal antibodies against Taylorella equigenitalis

Monoclonal antibodies were produced against Taylorella equigenitalis using two reference strains. Out of the 79 hybridoma clones shown to express antibodies to T equigenitalis by indirect immunofluorescence assay, 16 were selected for monoclonal antibody production and characterization. These clones recognized different field strains of T equigenitalis isolated in France. They showed no cross-reaction with bacterial strains with previously reported antigenic cross-reactivity, nor did they react with other bacteria commonly found in genital flora. The epitopes recognized by eight of the monoclonal antibodies were situated in proteins of 150, 120, 52.7 and 22 kDa. These epitopes were resistant to the extraction denaturing conditions. These monoclonal antibodies could be used as reagents for specific detection of T equigenitalis.

Chagas' disease after bone marrow transplantation

Chagas' disease is caused by Trypanosoma cruzi. It is endemic in Latin America where 16 to 18 million people are infected. Immunocompromised patients such as BMT recipients are at risk of Chagas' disease either due to reactivation or transfusion. We report a case of acute Chagas' disease in the setting of BMT.

Morphology of a human-derived YAC in yeast meiosis

In meiosis of human males DNA is packaged along pachytene chromosomes about 20 times more compactly than in meiosis of yeast. Nevertheless, a human-derived yeast artificial chromosome (YAC) shows the same degree of compaction of DNA as endogenous chromosomes in meiotic prophase nuclei of yeast. This suggests that in yeast meiosis, human and yeast DNA adopt a similar organization of chromatin along the pachytene chromosome cores. Therefore meiotic chromatin organization does not seem to be an inherent chromosomal property but is governed by the host-specific cellular environment. We suggest that there is a correlation between the less dense DNA packaging and the increased rate of recombination that has been reported for human-derived YACs as compared with human DNA in its natural environment.