Left atrial conduit function for left ventricular filling dynamics in patients with myocardial infarction

This study observed the left atrial function in determining filling dynamics of the left ventricle in patients with myocardial infarction. The study consisted of eight control subjects and ten patients with myocardial infarction. The left ventricular filling volume is considered to be composed of the left atrial passive emptying, active emptying, and conduit volumes. The change of left ventricular filling volume was correlated with that of conduit volume (r = .87, P < .01). However, the change of left ventricular filling volume did not have any correlation to those of left atrial passive emptying and active emptying volumes. These results suggested that the left atrial conduit function was important in determining filling dynamics of the left ventricle.     

Sphingosine 1-phosphate induces contraction of coronary artery smooth muscle cells via S1P2

OBJECTIVES: Sphingosine 1-phosphate (Sph-1-P), a bioactive lipid derived from activated platelets, may play an important role in coronary artery spasm and hence the pathogenesis of ischemic heart diseases, since we reported that a decrease in coronary blood flow was induced by this lysophospholipid in an in vivo canine heart model [Cardiovasc. Res. 46 (2000) 119]. In this study, metabolism related to and cellular responses elicited by Sph-1-P were examined in human coronary artery smooth muscle cells (CASMCs). METHODS AND RESULTS: [3H]Sphingosine (Sph), incorporated into CASMCs, was converted to [3H]Sph-1-P intracellularly, but its stimulation-dependent formation and extracellular release were not observed. Furthermore, the cell surface Sph-1-P receptors of S1P family (previously called EDG) were found to be expressed in CASMCs. Accordingly, Sph-1-P seems to act as an extracellular mediator in CASMCs. Consistent with Sph-1-P-elicited coronary vasoconstriction in vivo, Sph-1-P strongly induced CASMC contraction, which was inhibited by JTE-013, a newly-developed specific antagonist of S1P(2) (EDG-5). Furthermore, C3 exoenzyme or Y-27632 inhibited the CASMC contraction induced by Sph-1-P, indicating Rho involvement. Finally, exogenously-added [3H]Sph-1-P underwent a rapid degradation. Since lipid phosphate phosphatases, ectoenzymes capable of dephosphorylating Sph-1-P, were expressed in CASMCs, Sph-1-P may be dephosphorylated by the ectophosphatases. CONCLUSIONS: Sph-1-P, derived from platelets and dephosphorylated on the cell surface, may induce the contraction of coronary artery smooth muscle cells through the S1P(2)/Rho signaling.     

Direct Transmission of H. pylori from Challenged to Nonchallenged Mice in a Single Cage

To understand whether direct transmission of H. pylori occurs from infected mouse to noninfected mouse, the system using a mouse model we developed previously was tested. Six nude mice were challenged with H. pylori inocula; one group consisted of one challenged nude mouse 1 week after inoculation raised with four nonchallenged nude mice in a single cage. For the single cage, a polycarbonate cage or a mesh-floor cage was used. Then three groups were kept in a polycarbonate cage and the other three groups kept in a mesh-floor cage to avoid H. pylori transmission through stool. After coraising for 1, 2, or 3 weeks, all mice were sacrificed to determine the existence of H. pylori in the stomach, saliva, and stool by culture or PCR and H. pylori-associated gastritis. RAPD fingerprinting patterns using different primers of isolated strains from challenged and nonchallenged mice were compared to understand the origin of transmitted strains. During 3 weeks after coraising of H. pylori challenged and nonchallenged mice, H. pylori was detected in the stomachs in 3 of 12 nonchallenged mice in the polycarbonate cage and in 2 of 12 nonchallenged mice in the cage with a steel mesh floor. H. pylori was detected from saliva or stool in two nonchallenged, infected mice in the polycarbonate cage. Moreover, RAPD fingerprinting using different primers of the total five strains isolated from five nonchallenged, infected mice in both cages showed the same pattern and concordance with that of the challenged strain and the strains isolated from challenged mice. It is demonstrated that intimate interaction is the cause of H. pylori transmission via saliva and stool.     

Cytochrome P450 oxidoreductase gene mutations and Antley-Bixler syndrome with abnormal genitalia and/or impaired steroidogenesis: molecular and clinical studies in 10 patients

We report on molecular and clinical findings in 10 Japanese patients (four males and six females) from eight families (two pairs of siblings and six isolated cases) with Antley-Bixler syndrome accompanied by abnormal genitalia and/or impaired steroidogenesis. Direct sequencing was performed for all the 15 exons of cytochrome P450 oxidoreductase gene (POR), showing two missense mutations (R457H and Y578C), a 24-bp deletion mutation resulting in loss of nine amino acids and creation of one amino acid (L612_W620delinsR), a single bp insertion mutation leading to frameshift (I444fsX449), and a silent mutation (G5G). R457H has previously been shown to be a pathologic mutation, and computerized modeling analyses indicated that the 15A>G for G5G could disturb an exonic splicing enhancer motif, and the remaining three mutations should affect protein conformations. Six patients were compound heterozygotes, and three patients were R457H homozygotes; no mutation was identified on one allele of the remaining one patient. Clinical findings included various degrees of skeletal features, such as brachycephaly, radiohumeral synostosis, and digital joint contractures in patients of both sexes, normal-to-poor masculinization during fetal and pubertal periods in male patients, virilization during fetal life and poor pubertal development without worsening of virilization in female patients, and relatively large height gain and delayed bone age from the pubertal period in patients of both sexes, together with maternal virilization during pregnancy. Blood cholesterol was grossly normal, and endocrine studies revealed defective CYP17A1 and CYP21A2 activities. The results suggest that Antley-Bixler syndrome with abnormal genitalia and/or impaired steroidogenesis is caused by POR mutations, and that clinical features are variable and primarily explained by impaired activities of POR-dependent CYP51A1, CYP17A1, CYP21A2, and CYP19A1.     

Successful Unrelated Cord Blood Transplantation for Epstein-Barr Virus-Associated Lymphoproliferative Disease with Hemophagocytic Syndrome

We report a case of successful umbilical cord blood transplantation (CBT) for Epstein-Barr virus (EBV)-associated lymphoproliferative disease (LPD) in a 6-year-old girl. The patient had hemophagocytic syndrome with excessive circulating levels of EBV DNA that was refractory to immunochemotherapy. Multiple hepatosplenic lesions favored the diagnosis of EBV-associated LPD, although the aggressive course precluded the histopathologic diagnosis. Unrelated CB cells mismatched at 1 HLA locus were infused after patient conditioning with 900 mg/m2 etoposide, 2 g/m2 cytarabine, 16 mg/kg busulfan, and 200 mg/kg cyclophosphamide. Complete chimeric status was obtained on day 19 posttransplantation. Drug fever and acute graft-versus-host disease of the skin (grade II) were the major complications. A transient increase of EBV DNA 1 year after CBT indicated a primary EBV infection of the donor cells. The patient is alive with no evidence of disease 27 months after CBT. There has been no previous report of successful CBT for EBV-related LPD/lymphoma. CBT can be a curative treatment for the disease, even if no viral memory has been set in the stem cell source.     

Characterization of alphaT3-1 cells stably transfected with luteininzing hormone beta-subunit complementary deoxyribonucleic acid

Luteinizing hormone (LH) consists of alpha- and beta-subunits, and synthesis and secretion of LH are regulated by gonadotropin-releasing hormone (GnRH). In order to examine the molecular mechanisms by which GnRH regulates LH secretion, we transfected alphaT3-1 cells with rat LHbeta-subunit cDNA under the control of a constitutive promoter and established a stable cell line of LH2 cells which secreted LH in response to GnRH. Pulsatile and continuous GnRH pretreatments increased gene expression of the alpha-subunit and synthesis of LH, and enhanced the LH secretion by brief treatments with GnRH and 56 mM KCl. The LH secretions were partially blocked by elimination of extracellular Ca2+. GnRH-induced LH secretion was completely inhibited by calphostin C (a protein kinase C inhibitor) and 1 microM wortmannin. In contrast to the GnRH induction, high K+-induced LH secretion was inhibited by KN93, a Ca2+/calmodulin-dependent protein kinase II inhibitor, as well as by 1 microM wortmannin. We also confirmed that activation of cAMP-pathway induced LH secretion, but activation of mitogen-activated protein (MAP) kinase pathway was not involved in LH secretion. These results suggest that GnRH directly regulates LH secretion as well as LHbeta-subunit synthesis, and that LH2 cells are a useful model for the study of LH secretion induced by several secretagogues.