[Right bundle branch block: electrocardiographic and prognostic features]

The electrocardiographic appearances and the significance of right bundle branch block were described at the beginning of the 20th century. Typical appearances include prolongation > 0.12 s of the QRS complex, RR' or rR' or Rr' appearances in V1 and widened S waves in the leads exploring the left ventricle (SI, aVL, V5 and V6). A delay in the appearance of the intrinsic deflection > 0.08 s may also be observed in the right precordial leads and negative T waves with ST depression may be seen in V1 and sometimes in V2. Left axis deviation of the QRS complex greater than - 45 degrees suggests associated left anterior hemiblock. Right axis deviation beyond + 120 degrees is equivocal. The principal differential ECG diagnosis is the Brugada syndrome, a familial arrhythmogenic autosomal dominant cardiomyopathy of variable penetration. This diagnosis is suggested when ECG abnormalities are observed in patients with a personal or family history of sudden death. Right bundle branch block only seems to have haemodynamic consequences in cardiac failure with associated asynchrony of the left ventricle or in certain cases of right ventricular dilatation encountered in congenital heart disease. The prognosis of right bundle branch block in the absence of underlying cardiac disease is good but it may be poor in other cases, particularly coronary artery disease. Moreover, the prognosis of right bundle branch block to complete atrioventricular block is rare in the absence of associated cardiac disease.

Adenovirus fibre exchange alters cell tropism in vitro but not transgene-specific T CD8+ immune responses in vivo

Gene transfer with recombinant adenoviruses (rAds) is a powerful means of inducing an immune response against a transgene product. However, little is known about the mechanisms that underlie the induction of the immune response after intramuscular inoculation of adenovirus and, in particular, the relative role of the different cell types transduced. Several studies have suggested that CD8+ cytotoxic T lymphocyte responses elicited after inoculation of adenoviruses (Ads) are induced both by direct transduction of antigen presenting cells (APCs) and by cross-priming. In the present study, a library of fibre-chimeric rAds was screened in order to identify rAds with distinct capacities to express transgene product in murine cell types naturally found in muscle, i.e. myoblasts, endothelial cells (both representing non-APCs) and dendritic cells (representing APCs). Four selected pseudotypes, differing in their ability to infect muscular cells were used to immunize C57BL/6 mice. The relationship between the capacity to transduce non-APC or APC in vitro and the ability to induce humoral and cellular responses against the beta-galactosidase antigen after intramuscular inoculation were studied. Results indicate that CD8+ T cell responses against the beta-galactosidase antigen were similar after inoculation of the four viruses, thus revealing no direct relationship with their ability to transduce myoblasts, endothelial cells or dendritic cells in vitro.

Anti-IgE for chronic asthma in adults and children

BACKGROUND

Omalizumab is a recombinant humanised monoclonal antibody directed against immunoglobulin E (IgE) to inhibit the immune system's response to allergen exposure. Omalizumab is directed against the binding site of IgE for its high affinity Fc receptor. It prevents free serum IgE from attaching to mast cells and other effector cells and prevents IgE mediated inflammatory changes.

OBJECTIVES

To determine the efficacy of anti-IgE in patients with allergic asthma

SEARCH STRATEGY

We searched the Cochrane Airways Group Asthma trials register (February 2003) for potentially relevant studies.

SELECTION CRITERIA

Randomised controlled trials examining anti-IgE administered in any manner for any duration.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed study quality and extracted and entered data. Three modes of administration were identified from the published literature (inhaled, intravenous and subcutaneous injection). Subgroup analysis was performed by asthma severity. Data were extracted from published and unpublished sources.

MAIN RESULTS

Eight trials were included in the review, contributing a total of 2037 mild to severe allergic asthmatic participants with high levels of IgE. Treatment with intravenous and subcutaneous Omalizumab significantly reduced free IgE compared with placebo. Omalizumab led to a significant reduction in inhaled steroid consumption compared with placebo: -114 mcg/day (95% CI -150 to -78.13, two trials). There were significant increases in the number of participants who were able to reduce steroids by over 50%: odds ratio (OR) 2.50, 95% confidence interval (CI) 2.02 to 3.10 (four trials); or completely withdraw their daily steroid intake: OR 2.50, 95%CI 2.00 to 3.13 (four trials). Participants treated with Omalizumab were less likely to suffer an asthma exacerbation with treatment as an adjunct to steroids (OR 0.49, 95%CI 0.38 to 0.64, four trials), or as a steroid tapering agent (OR 0.47, 95% CI 0.37 to 0.60, four trials).

REVIEWERS' CONCLUSIONS

Omalizumab was significantly more effective than placebo at increasing the numbers of patients who were able to reduce or withdraw their inhaled steroids, but the mean difference in steroid consumption achieved with Omalizumab was of debatable clinical value. The impressive effects observed in control groups bring into question the true effect of Omalizumab. Omalizumab was effective in reducing asthma exacerbations as an adjunctive therapy to inhaled steroids. Omalizumab was well tolerated, although the safety profile requires longer term assessment. Patient and physician assessment of the drug was positive. Further assessment in paediatric and severe adult populations is necessary, as is double-dummy comparison with inhaled corticosteroids.

Anti-IgE for chronic asthma

BACKGROUND

Omalizumab is a recombinant humanised monoclonal antibody directed against immunoglobulin E (IgE) to inhibit the immune system's response to allergen exposure. Omalizumab is directed against the binding site of IgE for its high affinity Fc receptor. It prevents free serum IgE from attaching to mast cells and other effector cells and prevents IgE mediated inflammatory changes. The complexes of Omalizumab and IgE formed as a result of treatment are small and not thought to be able to trigger complement activation or give rise to immune complex mediated pathology.

OBJECTIVES

To determine the efficacy of anti-IgE in patients with allergic asthma.

SEARCH STRATEGY

We searched the Cochrane Airways Group Asthma trials register (February 2003) for potentially relevant studies.

SELECTION CRITERIA

Randomised control trials examining anti-IgE administered in any manner for any duration.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed study quality and extracted and entered data. Three modes of administration were identified from the published literature (inhaled, intravenous and subcutaneous injection). Subgroup analysis was performed by asthma severity. Data were extracted from published and unpublished sources.

MAIN RESULTS

Eight trials were included in the review, contributing a total of 2037 mild to severe allergic asthmatic participants with high levels of IgE. Treatment with intravenous and subcutaneous Omalizumab resulted in a 98 to 99% reduction in free IgE, reductions which were not observed following placebo treatment. Significant increases in the number of participants who were able to reduce (> 50% reduction in daily corticosteroid usage (four trials): odds ratio (OR) 2.50, 95% confidence interval (CI) 2.02 to 3.10; or completely withdraw their daily steroid intake (four trials): OR 2.50, 95%CI 2.00 to 3.13, were observed. Participants treated with Omalizumab were less likely to suffer an asthma exacerbation (stable steroid phase (three trials): OR 0.46, 95%CI 0.35 to 0.61; steroid reduction phase (three trials) OR 0.46, 95% CI 0.36 to 0.59).

REVIEWER'S CONCLUSIONS

Omalizumab was significantly more effective than placebo at increasing the numbers of patients who were able to reduce or withdraw their inhaled steroids and was effective in reducing asthma exacerbations. Omalizumab was well tolerated, although the safety profile requires longer term assessment. Patient and physician assessment of the drug was positive. Further assessment in paediatric and severe adult populations is necessary, as is comparison with inhaled corticosteroids.

Immunoreactive domains and integrin-binding motifs in adenovirus penton base capsomer

A panel of nine independent mouse monoclonal antibodies (MAbs) against penton base capsomers of subgenus C adenovirus serotypes 2 (Ad2) and 5 (Ad5) were isolated and characterized. Two of them (1D2 and 5A5), raised against Ad5 virion as the immunogen, bound to sodium dodecyl sulfate (SDS)-resistant and subgenus C-specific epitopes that were not present in subgenus B Ad3 penton base. The 1D2 and 5A5 epitopes were mapped to two distinct regions that did not belong to the main variable region carrying the integrin-binding RGD motif at position 340. For the other seven MAbs, raised against recombinant Ad2 penton base protein (9S-pentamers), the epitopes were sensitive to SDS-denaturation, but reacted with native Ad2, Ad5, and Ad3 penton base. The epitopes recognized by the nine MAbs and by polyclonal antipenton base antibodies defined three major immunoreactive regions. One (I) mapped to the N-terminal domain (residues 116-165); the other two regions were almost symmetrically disposed on both sides of the integrin-binding RGD motif at position 340, within residues 248-270 (II), and within residues 368-427 (III) in the C-terminal domain. Region II overlapped the fiber-binding site in penton base (residues 254-260). None of the MAbs showed any detectable virus neutralization effect, but they all slightly augmented the efficiency of Ad-mediated gene transfer. Although none of their epitopes included the RGD-340 tripeptide, substitutions of the arginine residue in the RGD motif abolished the reactivity of six individual and distant epitopes, suggesting a major conformational role for the RGD-containing domain.

Single inoculation of replication-defective adenovirus-vectored vaccines at birth in piglets with maternal antibodies induces high level of antibodies and protection against pseudorabies

In neonates, one limitation of vaccination is its inhibition by maternal antibodies. We show that piglets vaccinated intramuscularly once at birth with recombinant replication-defective adenoviruses developed comparable neutralizing antibody response against pseudorabies virus, independently of the presence or absence of maternal antibodies, and were partially protected against challenge 16 weeks later.

Clearance of infection in cats naturally infected with feline coronaviruses is associated with an anti-S glycoprotein antibody response

We have investigated by Western blotting the antibody responses against the three major structural proteins in cats naturally infected with feline coronaviruses that cleared virus infection (group I), established chronic asymptomatic infection (group II) or were sick (group III). The cats of group I developed an anti-S glycoprotein response that was, relative to the anti-M glycoprotein response, at least 30-fold higher than that of chronically infected cats from groups II and III. These results suggest that the anti-S glycoprotein response against antigenic domains revealed by Western blot is associated with clearance of the virus after natural infection, and is not a risk factor for the establishment of a chronic infection.

[Effort-induced macroscopic hematuria revealing segmental and congenital absence of inferior vena cava]

Absence of inferior vena cava (IVC) is an uncommon congenital abnormality with few clinical repercussions. We report the case of a 39 year old man with chronic pelvic pain, in whom a macroscopic hematuria episode occurring during exercise led to the discovery of an echographic pelvic venous stasis syndrome. Abdominal and pelvic computed tomography scanning then magnetic resonance imaging of inferior vena cava revealed absence of the postrenal segment of IVC with azygos continuation and considerable collateral venous derivations, leading to pelvic cavernoma.

Disomy rates for chromosomes 14 and 21 studied by fluorescent in-situ hybridization in spermatozoa from three men over 60 years of age

In order to further investigate the paternal-age effect on meiotic non-disjunction rates for the chromosomes 14 and 21, we examined spermatozoa from three men aged > 60, using multicolour fluorescent in-situ hybridization (FISH). More than 10,000 sperm cells were analysed for each of the three subjects (A, B and C), by simultaneously hybridizing two YAC probes specific for chromosomes 14 and 21 respectively using two-colour FISH. The results show that the disomy 21 rates observed in the spermatozoa of two out of the three men aged > 60 years were higher (1.02 and 1.17% respectively) than the rates observed in eight control adults aged < 30 years (mean frequency 0.48%) analysed under similar conditions. These results suggest that there may be a small effect of age on male non-disjunction rates for chromosome 21. However, before any firm conclusions could be drawn, a much bigger sample of older men would have to be compared with a paired control population using the same FISH experimental approach.

Effective priming of neonates born to immune dams against the immunogenic pseudorabies virus glycoprotein gD by replication-incompetent adenovirus-mediated gene transfer at birth

One of the main limitations of the vaccination of neonates from vaccinated or infected mothers is the interference by inherited maternal antibodies, which are known to inhibit the immune response against both live and inactivated vaccines. The efficiency of bypassing this inhibition by the transfer of an immunogenic glycoprotein gene, the gD gene of pseudorabies virus (PRV), into neonates was explored. The experiments were conducted in 1-day-old piglets, which are immunocompetent at birth. The same transcription unit (gD of PRV under the control of the adenovirus major late promoter) was delivered intramuscularly at birth either in the form of naked DNA or cloned in the genome of a replication-defective adenovirus. A booster injection of a conventional live PRV vaccine strain was given at 10 weeks of age, the replication of which was greatly restricted by the residual amounts of colostral antibodies in control animals. Piglets were challenged at the age of 16 weeks with a virulent PRV strain. The replication-defective adenovirus was able to efficiently prime piglets born to immune dams against gD in such a way that inoculation with the Bartha strain protected them against a subsequent challenge with the same level of efficacy in piglets born to naive or immune dams. In contrast, piglets born to immune dams into which the gD gene was not transferred, or transferred as naked DNA at birth, were not protected. These results open the way for early immunization of neonates born to vaccinated or infected mothers.

Efficacy of replication-defective adenovirus-vectored vaccines: protection following intramuscular injection is linked to promoter efficiency in muscle representative cells

To investigate the respective role of transduced cells in the induction of immune response following intramuscular inoculation of adenovirus-based vaccines, we generated several replication-defective adenoviruses expressing the glycoprotein D gene of pseudorabies virus under the control of four different promoters: major late promoter of adenovirus type 2, human cytomegalovirus immediate-early promoter/enhancer (CMV), Rous sarcoma virus-long terminal repeat promoter, and human desmin gene 5' regulatory region (DES). All the adenovirus constructs were able to fully protect mice, in the contrary of direct DNA inoculation of plasmids harboring the same transcription units. The far most effective adenovirus constructs, on the criterion of protective doses and specific antibody response induction, were those in which the foreign gene was driven by the DES or CMV promoter. Wide variations in promoter strength in vitro were evidenced in several cell culture types representative of putative target cells following muscular inoculation (myoblasts, myotubes, fibroblasts, macrophages, and endothelial cells). The level of efficacy in vivo, was not correlated with the level of expression in vitro in myotubes, but paralleled the level of expression in endothelial cells and in myoblasts. Together with previously published data, these results suggest that, following adenovirus injection, locally produced cytokines may induce myoblasts to act as local antigen presenting cells.

Study of the delivery of the gD gene of pseudorabies virus to one-day-old piglets by adenovirus or plasmid DNA as ways to by-pass the inhibition of immune response by colostral antibodies

In the present study, it was shown that piglets with maternal antibodies, which had been primed with a replication-defective adenovirus that expresses the pseudorabies virus (PRV) glycoprotein gD and boosted with the Bartha vaccine strain at 10 weeks of age are equally protected clinically upon a challenge as piglets without maternal antibodies vaccinated with the same approach or with the Bartha vaccine strain alone. Priming with a plasmid that expresses gD was less efficient.

Meiotic behaviour of sex chromosomes investigated by three-colour FISH on 35,142 sperm nuclei from two 47,XYY males

Meiotic segregation of sex chromosomes from two fertile 47,XYY men was analysed by a three-colour fluorescence in situ hybridisation procedure. This method allows the identification of hyperhaploidies (spermatozoa with 24 chromosomes) and diploidies (spermatozoa with 46 chromosomes), and their meiotic origin (meiosis I or II). Alpha-satellite probes specific for chromosomes X, Y and 1 were observed simultaneously in 35,142 sperm nuclei. For both 47,XYY men (24,315 sperm nuclei analysed from one male and 10,827 from the other one) the sex ratio differs from the expected 1:1 ratio (P < 0.001). The rates of disomic Y, diploid YY and diploid XY spermatozoa were increased for both 47,XYY men compared with control sperm (142,050 sperm nuclei analysed from five control men), whereas the rates of hyperhaploidy XY, disomy X and disomy 1 were not significantly different from those of control sperm. These results support the hypothesis that the extra Y chromosome is lost before meiosis with a proliferative advantage of the resulting 46,XY germ cells. Our observations also suggest that a few primary spermatocytes with two Y chromosomes are able to progress through meiosis and to produce Y-bearing sperm cells. A theoretical pairing of the three gonosomes in primary spermatocytes with an extra sex chromosome, compatible with active spermatogenesis, is proposed.

Increased aneuploid frequency in spermatozoa from a Hodgkin's disease patient after chemotherapy and radiotherapy

The frequency of sperm aneuploidy was investigated by fluorescence in situ hybridization (FISH) in a Hodgkin's disease patient shortly after he had received chemotherapy and radiotherapy. Sperm karyotyping of the same patient had previously shown multiple structural abnormalities in most spermatozoa immediately after radiotherapy (day 0), whereas most spermatozoa collected 5 wk later (day 38) exhibited normal metaphase divisions (Rousseaux et al., 1993). Variations in the frequency of aneuploidy could not be detected by sperm karyotyping. Multicolor FISH on interphase spermatozoa revealed an increase in the rate of disomy for chromosomes 1, 6, 11, X, and Y at day 0 as well as at day 38. The high frequency of 24,XY (nondisjunction at meiosis I) and 24,XX (nondisjunction at meiosis II) spermatozoa (8.46% and 1.64% at day 0, respectively) from the Hodgkin's disease patient suggests that both meiosis I and II are affected and that the X chromosome is frequently involved in such malsegregation events. The rate of 46,XY diploidy was also increased in the patient's sperm, up to 0.62% at day 0. While radiotherapy probably affected the postmeiotic cells (spermatids), the patient's cancer and/or chemotherapy are the two major factors that could have affected the dividing spermatogonia and/or spermatocytes, resulting in high aneuploidy rates.

[Intracytoplasmic sperm injection and Klinefelter syndrome]

Sperm cytogenetic study in two patients with Klinefelter's syndrome have demonstrated that there existed a risk low but highly significant, to transmit a sex chromosome abnormality to the offsprings. This result argues for a systematic karyotype before ICSI, and if such mosaïcs can be treated by ICSI, they must be firstly associated to a genetic counselling.

Molecular diagnosis of t(11;14) in mantle cell lymphoma using two-colour interphase fluorescence in situ hybridization

t(11;14) is observed in up to 70% of mantle cell lymphoma (MCL) cases and is therefore an important diagnostic element. In routine practice, detection of t(11;14) by conventional cytogenetic techniques is hindered by the low yield and quality of tumour metaphases. Molecular techniques (Southern blot, PCR) are unable to detect a large number of 11q13 breakpoints due to scattering over distances up to 1 Mb. Using 23 MCL patients with karyotypically determined t(11;14) and eight negative controls, we have devised a two-colour interphase FISH assay for detection of the 14q + chromosome. We chose an 11q13 probe telomeric to the major 11q13 translocation cluster sites and an IGH probe centromeric of the 14q32 breakpoints. This method detected the translocation in all 23 t(11;14) positive patients, with an overall average of 60% nuclei showing colocalized signals. Widespread application of this technique will constitute an important diagnostic aid in clinical management of MCL patients. Since FISH is a convenient method for retrospective analysis of large numbers of patient specimens, this method should contribute to an accurate estimation of t(11;14) frequency in MCL and other chronic B-cell malignancies and consequently to their better nosological characterization.

Increased incidence of hyperhaploid 24,XY spermatozoa detected by three-colour FISH in a 46,XY/47,XXY male

Meiotic segregation of gonosomes from a 46,XY/47,XXY male was analysed by a three-colour fluorescence in situ hybridisation (FISH) procedure. This method allows the identification of hyperhaploid spermatozoa (with 24 chromosomes), diploid spermatozoa (with 46 chromosomes) and their meiotic origin (meiosis I or II). Alpha satellite DNA probes specific for chromosomes X, Y and 1 were observed on 27,097 sperm nuclei. The proportions of X- and Y-bearing sperm were estimated to 52.78% and 43.88%, respectively. Disomy (24,XX, 24,YY, 24,X or Y,+1) and diploidy (46,XX, 46,YY, 46,XY) frequencies were close to those obtained from control sperm, whereas the frequency of hyperhaploid 24,XY spermatozoa (2.09%) was significantly increased compared with controls (0.36%). These results support the hypothesis that a few 47,XXY germ cells would be able to complete meiosis and to produce mature spermatozoa.

Sperm nuclei analysis of a Robertsonian t(14q21q) carrier, by FISH, using three plasmids and two YAC probes

The meiotic segregation of chromosomes 14 and 21 was analysed in 1116 spermatozoa from an oligoasthenospermic carrier of a Robertsonian translocation t(14q21q), and in 16,392 spermatozoa from a control donor, using two-colour fluorescence in situ hybridisation (FISH). Two YAC probes (cloned in yeast artificial chromosomes) specific for regions on the long arms of these chromosomes were co-hybridised. Of the spermatozoa, 12% were unbalanced, resulting from adjacent segregations. Chromosomes X, Y and 1 were also simultaneously detected in 1335 spermatozoa from the same carrier. Whereas gonosomal disomy rates were not significantly different from those of the control donors, disomy 1 were slightly but significantly increased to 0.7%. The diploidy rate was also slightly increased to approximately 1% in the translocation carrier.

Meiotic segregation in males heterozygote for reciprocal translocations: analysis of sperm nuclei by two and three colour fluorescence in situ hybridization

The meiotic segregation of chromosomes was analysed in three reciprocal translocation carriers, using FISH on interphase spermatozoa. The segregation pattern was first studied in 27,844 spermatozoa from two siblings carrying the reciprocal translocation t(6;11)(q14;p14). Three centromeric probes, specific for chromosomes 6, 11 and 1, were simultaneously hybridized so that all centric fragments as well as the ploidy of each cell could be determined by three colour FISH. For both subjects, the respective frequencies of alternate/adjacent 1, adjacent 2, 3:1 and 4:0 segregation modes were 88%, 9%, 3+ and < 1%. In another reciprocal translocation t(2;14)(p23.1;q31), a two colour FISH analysis was performed on 4,610 spermatozoa, using a chromosome 2 centromeric probe and a YAC probe located on the centric fragment of chromosome 14. Frequencies of alternate/adjacent 1, adjacent 2, and 3:1 segregations were 89%, 5.2%, and 5.8% respectively. The segregation of chromosomes X, Y and 1 were also analyzed with three colour FISH on the spermatozoa from all three translocation carriers, in order to detect an interchromosomal effect. Aneuploidy rates for the X and Y chromosomes were found to be in the same range in the three translocation carriers and control donors, but disomy 1 rates were slightly increased in the translocation carriers.

Meiotic segregation of the X and Y chromosomes and chromosome 1 analyzed by three-color FISH in human interphase spermatozoa

Meiotic segregation of the X and Y chromosomes and chromosome 1 was analyzed by three-color fluorescence in situ hybridization (FISH) in 94,575 human interphase spermatozoa from four control subjects. More than 99% of the sperm cells were labeled. The proportions of X- and Y-bearing sperm were estimated to be 49.83% and 48.30%, respectively. The disomy rates were 0.04%, 0.009%, and 0.20% for the X and Y chromosomes and chromosome 1, respectively. Hyperhaploidy with an extra gonosome was found in 0.34% of spermatozoa, due to nondisjunction during meiosis I. The frequency of diploidy was 0.11% at meiosis I and 0.036% at meiosis II. Cohybridization of one autosomal and two gonosomal probes, in three-color FISH in interphase spermatozoa, seems to accurately discriminate diploidies from disomies, as well as the meiotic origin of gonosomal aneuploidies in sperm cells.

Male meiotic segregation of gonosomes analysed by two colour FISH in human interphase spermatozoa

Human meiotic segregation of X and Y chromosomes was simultaneously analysed by dual fluorescence in situ hybridization (FISH) on 10,638 interphase spermatozoa from the same donor. A modified method for sperm decondensation ensured access of both X and Y probes to the sperm chromatin and a 99% hybridization efficiency. Expected sex ratios were obtained (49.30% haploidy X and 49.22% haploidy Y). The frequencies of meiotic II non-disjunctions for X and Y chromosomes (0.05%) were similar to those observed in sperm karyotypes after heterospecific fertilization of hamster eggs. In contrast, the frequency of XY bearing cells was significantly higher (0.42%). However, XY cells detected by FISH could either be diploid somatic cells, diploid germinal cells or hyperhaploid XY spermatozoa, the latter resulting from meiotic I non-disjunctions.