Background: Despite high patency rates, primary angioplasty for myocardial infarction does not necessarily result in optimal myocardial reperfusion and limitation of infarct size. Experimentally, ...trimetazidine limits infarct size, decreases platelet aggregation, and reduces leukocyte influx into the infarct zone. To assess trimetazidine as adjunctive therapy to primary angioplasty for acute myocardial infarction a prospective, double-blind, placebo-controlled pilot trial was performed.
Methods: 94 patients with acute myocardial infarction were randomized to receive trimetazidine (40 mg bolus followed by 60 mg/day intravenously for 48 h) (
n=44) or placebo (
n=50), starting before recanalization of the infarct vessel by primary angioplasty. Patients underwent continuous ST-segment monitoring to assess return of ST-segment deviation to baseline and presence of ST-segment exacerbation at the time of vessel recanalization. Infarct size was measured enzymatically from serial myoglobin measurements. Left ventricular angiography was performed before treatment and repeated at day 14.
Results: Blinded ST segment analysis showed that despite higher initial ST deviation from baseline in the trimetazidine group (355 (32) vs. 278 (29) μV,
P=0.07), there was an earlier and more marked return towards baseline within the first 6 h than in the placebo group (
P=0.014) (change: 245 (30) vs. 156 (31) μV respectively,
P=0.044). There was a trend towards less frequent exacerbation of ST deviation at the time of recanalization in the trimetazidine group (23.3 vs. 42.2%,
P=0.11). There was no difference in left ventricular wall motion at day 14, or in enzymatic infarct size. There was no side effect from treatment. Clinical outcomes were similar between groups.
Conclusion: Trimetazidine was safe and led to earlier resolution of ST-segment elevation in patients treated by primary angioplasty for acute myocardial infarction.
This prospective study was conducted to determine the percentage of patients with long-term pacemaker dependency after successful radiofrequency ablation of the atrioventricular junction. Abrupt ...inhibition of the pacemaker was performed 13.5 ± 8.1 months after ablation in 59 patients. A ≥5-second asystole was considered to indicate pacemaker dependency. Pacemaker dependency was present in 18 patients. Absence of escape rhythm immediately after ablation was strongly associated with a higher incidence of long-term pacemaker dependency. The following variables were not associated with pacemaker dependency: age, presence of cardiac disease, presence of preablation bundle branch block, number of radiofrequency applications, a bilateral approach for ablation, and continuation of antiarrhythmic therapy after ablation. We concluded that (1) long-term pacemaker dependency is present in 30.5% of the patients after successful atrioventricular junction radiofrequency ablation and (2) absence of escape rhythm immediately after ablation predicts long-term pacemaker dependency. (Am Heart J 1997;133:580-4.)
Ten to fifteen percent of couples are confronted with infertility and a male factor is involved in approximately half the cases. A genetic etiology is likely in most cases yet only few genes have ...been formally correlated with male infertility. Homozygosity mapping was carried out on a cohort of 20 North African individuals, including 18 index cases, presenting with primary infertility resulting from impaired sperm motility caused by a mosaic of multiple morphological abnormalities of the flagella (MMAF) including absent, short, coiled, bent, and irregular flagella. Five unrelated subjects out of 18 (28%) carried a homozygous variant in DNAH1, which encodes an inner dynein heavy chain and is expressed in testis. RT-PCR, immunostaining, and electronic microscopy were carried out on samples from one of the subjects with a mutation located on a donor splice site. Neither the transcript nor the protein was observed in this individual, confirming the pathogenicity of this variant. A general axonemal disorganization including mislocalization of the microtubule doublets and loss of the inner dynein arms was observed. Although DNAH1 is also expressed in other ciliated cells, infertility was the only symptom of primary ciliary dyskinesia observed in affected subjects, suggesting that DNAH1 function in cilium is not as critical as in sperm flagellum.
Multiple morphological abnormalities of the sperm flagellum (MMAF) is a severe form of male infertility defined by the presence of a mosaic of anomalies, including short, bent, curled, thick, or ...absent flagella, resulting from a severe disorganization of the axoneme and of the peri-axonemal structures. Mutations in DNAH1, CFAP43, and CFAP44, three genes encoding axoneme-related proteins, have been described to account for approximately 30% of the MMAF cases reported so far. Here, we searched for pathological copy-number variants in whole-exome sequencing data from a cohort of 78 MMAF-affected subjects to identify additional genes associated with MMAF. In 7 of 78 affected individuals, we identified a homozygous deletion that removes the two penultimate exons of WDR66 (also named CFAP251), a gene coding for an axonemal protein preferentially localized in the testis and described to localize to the calmodulin- and spoke-associated complex at the base of radial spoke 3. Sequence analysis of the breakpoint region revealed in all deleted subjects the presence of a single chimeric SVA (SINE-VNTR-Alu) at the breakpoint site, suggesting that the initial deletion event was potentially mediated by an SVA insertion-recombination mechanism. Study of Trypanosoma WDR66’s ortholog (TbWDR66) highlighted high sequence and structural analogy with the human protein and confirmed axonemal localization of the protein. Reproduction of the human deletion in TbWDR66 impaired flagellar movement, thus confirming WDR66 as a gene associated with the MMAF phenotype and highlighting the importance of the WDR66 C-terminal region.
Azoospermia, characterized by the absence of spermatozoa in the ejaculate, is a common cause of male infertility with a poorly characterized etiology. Exome sequencing analysis of two azoospermic ...brothers allowed the identification of a homozygous splice mutation in SPINK2, encoding a serine protease inhibitor believed to target acrosin, the main sperm acrosomal protease. In accord with these findings, we observed that homozygous Spink2 KO male mice had azoospermia. Moreover, despite normal fertility, heterozygous male mice had a high rate of morphologically abnormal spermatozoa and a reduced sperm motility. Further analysis demonstrated that in the absence of Spink2, protease‐induced stress initiates Golgi fragmentation and prevents acrosome biogenesis leading to spermatid differentiation arrest. We also observed a deleterious effect of acrosin overexpression in HEK cells, effect that was alleviated by SPINK2 coexpression confirming its role as acrosin inhibitor. These results demonstrate that SPINK2 is necessary to neutralize proteases during their cellular transit toward the acrosome and that its deficiency induces a pathological continuum ranging from oligoasthenoteratozoospermia in heterozygotes to azoospermia in homozygotes.
Synopsis
SPINK2, a serine protease inhibitor, is believed to target the acrosin, the main sperm acrosomal protease. This study confirms SPINK2 in that role and finds it essential for spermiogenesis as SPINK2 deficiency induces a post meiotic block at the round spermatid stage leading to azoospermia in mice and men.
In round spermatids, SPINK2 is necessary to inactivate the acrosin during its transit through the endoplasmic reticulum and the Golgi apparatus.
In the absence of SPINK2, acrosin can auto‐activate, disorganize the Golgi apparatus, prevent the production of the acrosome and induce a block at the round spermatid stage.
A reduced amount of SPINK2 in heterozygotes is also deleterious, inducing a milder phenotype of oligozoospermia and/or teratozoospermia without a systematic infertility.
SPINK2, a serine protease inhibitor, is believed to target the acrosin, the main sperm acrosomal protease. This study confirms SPINK2 in that role and finds it essential for spermiogenesis as SPINK2 deficiency induces a post meiotic block at the round spermatid stage leading to azoospermia in mice and men.
Sperm-head elongation and acrosome formation, which take place during the last stages of spermatogenesis, are essential to produce competent spermatozoa that are able to cross the oocyte zona ...pellucida and to achieve fertilization. During acrosome biogenesis, acrosome attachment and spreading over the nucleus are still poorly understood and to date no proteins have been described to link the acrosome to the nucleus. We recently demonstrated that a deletion of DPY19L2, a gene coding for an uncharacterized protein, was responsible for a majority of cases of type I globozoospermia, a rare cause of male infertility that is characterized by the exclusive production of round-headed acrosomeless spermatozoa. Here, using Dpy19l2 knockout mice, we describe the cellular function of the Dpy19l2 protein. We demonstrate that the protein is expressed predominantly in spermatids with a very specific localization restricted to the inner nuclear membrane facing the acrosomal vesicle. We show that the absence of Dpy19l2 leads to the destabilization of both the nuclear dense lamina (NDL) and the junction between the acroplaxome and the nuclear envelope. Consequently, the acrosome and the manchette fail to be linked to the nucleus leading to the disruption of vesicular trafficking, failure of sperm nuclear shaping and eventually to the elimination of the unbound acrosomal vesicle. Finally, we show for the first time that Dpy19l3 proteins are also located in the inner nuclear envelope, therefore implying that the Dpy19 proteins constitute a new family of structural transmembrane proteins of the nuclear envelope.
During the initiation step of bacterial genome replication, replicative helicases depend on specialized proteins for their loading onto oriC. DnaC and DnaI were the first loaders to be characterized. ...However, most bacteria do not contain any of these genes, which are domesticated phage elements that have replaced the ancestral and unrelated loader gene dciA several times during evolution. To understand how DciA assists the loading of DnaB, the crystal structure of the complex from Vibrio cholerae was determined, in which two VcDciA molecules interact with a dimer of VcDnaB without changing its canonical structure. The data showed that the VcDciA binding site on VcDnaB is the conserved module formed by the linker helix LH of one monomer and the determinant helix DH of the second monomer. Interestingly, DnaC from Escherichia coli also targets this module onto EcDnaB. Thanks to their common target site, it was shown that VcDciA and EcDnaC could be functionally interchanged in vitro despite sharing no structural similarity. This represents a milestone in understanding the mechanism employed by phage helicase loaders to hijack bacterial replicative helicases during evolution.
The crystallographic structure of the DnaB·DciA complex from Vibrio cholerae reveals that the various helicase loaders share the same binding site on the bacterial replicative helicase, albeit with differences in their loading mechanisms.
Adult bone marrow (BM)-derived stem cells, including hematopoietic stem cells (HSCs) and MSCs, represent an important source of cells for the repair of a number of damaged tissues. In contrast to ...HSCs, the soluble factors able to induce MSC migration have not been extensively studied. In the present work, we compared the in vitro migration capacity of human BM-derived MSCs, preincubated or not with the inflammatory cytokines interleukin 1beta (IL1beta) and tumor necrosis factor alpha (TNFalpha), in response to 16 growth factors (GFs) and chemokines. We show that BM MSCs migrate in response to many chemotactic factors. The GFs platelet-derived growth factor-AB (PDGF-AB) and insulin-like growth factor 1 (IGF-1) are the most potent, whereas the chemokines RANTES, macrophage-derived chemokine (MDC), and stromal-derived factor-1 (SDF-1) have limited effect. Remarkably, preincubation with TNFalpha leads to increased MSC migration toward chemokines, whereas migration toward most GFs is unchanged. Consistent with these results, BM MSCs express the tyrosine kinase receptors PDGF-receptor (R) alpha, PDGF-Rbeta, and IGF-R, as well as the RANTES and MDC receptors CCR2, CCR3, and CCR4 and the SDF-1 receptor CXCR4. TNFalpha increases CCR2, CCR3, and CCR4 expression (as opposed to that of CXCR4), together with RANTES membrane binding. These data indicate that the migration capacity of BM MSCs is under the control of a large range of receptor tyrosine kinase GFs and CC and CXC chemokines. Most chemokines are more effective on TNFalpha-primed cells. Our results suggest that the mobilization of MSCs and their subsequent homing to injured tissues may depend on the systemic and local inflammatory state. Disclosure of potential conflicts of interest is found at the end of this article.
We have studied the plasma membrane protein phenotype of human culture-amplified and native bone marrow mesenchymal stem cells (BM MSCs). We have found, using microarrays and flow cytometry, that ...cultured cells express specifically 113 transcripts and 17 proteins that were not detected in hematopoietic cells. These antigens define a lineage-homogenous cell population of mesenchymal cells, clearly distinct from the hematopoietic lineages, and distinguishable from other cultured skeletal mesenchymal cells (periosteal cells and synovial fibroblasts). Among the specific membrane proteins present on cultured MSCs, 9 allowed the isolation from BM mononuclear cells of a minute population of native MSCs. The enrichment in colony-forming units–fibroblasts was low for CD49b, CD90, and CD105, but high for CD73, CD130, CD146, CD200, and integrin alphaV/beta5. In addition, the expression of CD73, CD146, and CD200 was down-regulated in differentiated cells. The new marker CD200, because of its specificity and immunomodulatory properties, deserves further in-depth studies.
An international outbreak linked to oyster consumption involving a group of over 200 people in Italy and 127 total subjects in 13 smaller clusters in France was analyzed using epidemiological and ...clinical data and shellfish samples. Environmental information from the oyster-producing area, located in a lagoon in southern France, was collected to investigate the possible events leading to the contamination. Virologic analyses were conducted by reverse transcription-PCR (RT-PCR) using the same primer sets for both clinical and environmental samples. After sequencing, the data were analyzed through the database operated by the scientific network FoodBorne Viruses in Europe. The existence of an international collaboration between laboratories was critical to rapidly connect the data and to fully interpret the results, since it was not obvious that one food could be the link because of the diversity of the several norovirus strains involved in the different cases. It was also demonstrated that heavy rain was responsible for the accidental contamination of seafood, leading to a concentration of up to hundreds of genomic copies per oyster as detected by real-time RT-PCR.
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