[Homograft implantation in heart surgery]. / Homograftimplantationen in der Herzchirurgie.

In order to fulfill in the field of cardiothoracic surgery the obligations of patient-care and research in a university facility according to the international standard it is nowadays absolutely necessary to run a homograft bank. Implantation of an allograft is a preferable choice for a number of different operations, i.e. in aortic valve endocarditis, complex congenital heart disease, Ross' operation and others. Furthermore, in children, women of childbearing age and patients in whom anticoagulation is contraindicated, heart valve replacement with allografts has become routine. The most important advantages of allografts are the excellent hemodynamic qualities and the low risk endocarditis. Anticoagulation is not necessary, because there is no risk for thromboembolism or hemolysis. For the patients mentioned above, these factors are decisive for their quality of life and their prognosis. Because of the shortage of donor organs and the priority of heart transplantation over allograft harvesting, the use of allografts should be limited to the above mentioned indications, mechanical and bioprothetic valves and, just lately available, bioprothetic valves from autogenous pericardium are appropriate.

Evidence against a role of nitric oxide in the indirect negative inotropic-effect of M-cholinoceptor stimulation in human ventricular myocardium.

Nitric oxide (NO) has been reported to mediate several effects in response to muscarinic cholinergic stimulation in cardiovascular tissues. Recently, an attenuation of guinea pig cardiac myocyte contraction by NO has been described. The aim of the present study was to determine whether the indirect negative inotropic effect of M-cholinoceptor stimulation in human myocardium is in part due to an effect of endogenous NO. Therefore, the effect of carbachol was studied under control conditions and during inhibition of NO-synthase by pretreatment with NG-monomethyl-L-arginine (NMMA). Functional experiments were performed in isolated, electrically driven (1 Hz, 37 degrees C) left ventricular papillary muscle strips of human myocardium. Since cytokines have been reported to be increased in the serum of patients with heart failure and could induce NO-synthase activity in failing myocardium, we compared samples from nonfailing and terminally failing (classified as NYHA IV) hearts. The indirect negative inotropic effect of carbachol (10 mumol/l) was studied in the presence of the beta-adrenoceptor agonist isoprenaline (0.03 mumol/l). After stimulation with isoprenaline, carbachol significantly (P < 0.05) reduced force of contraction. This effect was diminished in failing myocardium compared to nonfailing, probably due to the diminished inotropic response most likely due to the lower cAMP levels in response to beta-adrenoceptor stimulation in the former condition. Pretreatment with NMMA (100 mumol/l) altered the antiadrenergic effect of carbachol neither in nonfailing nor in failing preparations. Furthermore, inhibition of guanylyl cyclase, the target enzyme of NO, by preincubation with methylene blue (10 mumol/l) for 30 min had no effect on the carbachol-induced decrease in force of contraction.(ABSTRACT TRUNCATED AT 250 WORDS)

Two antigenic groups of human coronaviruses detected by using enzyme-linked immunosorbent assay.

Paired sera from volunteers inoculated with one of the five recently isolated strains of human coronavirus (HCV), AD, GI, HO, PA, and RO, none of which has been grown in tissue culture, or with strain OC38 were tested against coronavirus antigens by enzyme-linked immunosorbent assay. When HCV strains OC43, 229E, or the 229E-related tissue culture-adapted strains PR and TO were used as antigens, it was shown that all strains fell into one of two antigenic groups. The HCV OC43 group was comprised of strains OC43, GI, HO, and RO, and the HCV 229E group contained strains AD and PA as well as the tissue culture-adapted strains PR, TO, and KI. Enzyme-linked immunosorbent assay of the paired sera with the coronavirus mouse hepatitis virus strain 3 as antigen confirmed the relationship of this virus to the HCV OC43 group but not to the HCV 229E group.

Antibody to virus components in volunteers experimentally infected with human coronavirus 229E group viruses.

Antibody rises to various virus subcomponents were measured by enzyme-linked immunosorbent assay in the paired sera of volunteers experimentally infected with human coronavirus 229E group viruses. Most of the antibody made during infection was directed against the virus surface projections, with only small amounts of antibody made against membrane or ribonucleoprotein components.

Enzyme-linked immunosorbent assay for coronaviruses HCV 229E and MHV 3.

The antigenic relationship between human cornonavirus strain 229E (HCV 229E) and mouse hepatitis virus strain 3 (MHV 3) was studied by means of the indirect form of enzyme-linked immunosorbent assay (ELISA). A cross-reaction was found with hyprimmune rabbit sera between HCV 229E and MHV 3 which may be due to the adherence of bovine serum componeants from tissue culture media, which were present on virus particles even after extensive purification. No cross-reaction was observed with immune sera absorbed with bovine serum, or with HCV 229E grown in tissue culture without serum. This indirect ELISA with HCV 229E may prove to be useful for studies with human sera.

The genome of human coronavirus strain 229E.

The genomic RNA of human coronavirus strain 229E (HCV 229E) migrated on polyacrylamide gels as a single peak with a mol. wt. of 5.8 X 10(6). Denaturation of the genome with formaldehyde did not alter its electrophoretic mobility, which suggests that the HCV 229E genome is a single-stranded molecule. At least 30% of the genomic RNA was shown to contain covalently attached polyadenylic acid [poly(A)]sequences by binding the RNA to an oligo(dT)-cellulose column. These poly(A) tracts were shown to be about 70 nucleotides in length by measuring the resistance to digestion of HCV 229E RNA with pancreatic and T1 RNases. Finally, the genomic RNA was shown to terminate at or near the 3'-terminus on the basis of its susceptibility to polynucleotide phosphorylase.

Polypeptides of the surface projections and the ribonucleoprotein of avian infectious bronchitis virus.

Purified avian infectious bronchitis virus was digested with bromelain (0.7 mg/ml), and the surface projections were removed. Polyacrylamide gel electrophoresis of the polypeptides from these bromelain-treated particles showed that VP1, VP2, and VP5 were missing from the seven polypeptides. VP1 to VP7, that were present in untreated virus preparations. Milder bromelain treatment (0.07 mg/ml) left visible surface projections and polypeptides comprising VP1 and VP2 intact, but removed VP5. Thus, there are apparently two types of surface projections on the virus particle. The ribonucleoprotein complex was released from virus particles disrupted with 1% Nonidet P-40. The proportion of VP6 in such preparations was greatly reduced, implying that VP6 is the structural polypeptide of the ribonucleoprotein. Polypeptides VP1, VP2, VP4, and VP5 are glycosylated, but none of the polypeptides contains lipid.

The polypeptide composition of avain infectious bronchitis virus particles.

Egg grown avian infectious bronchitis virus (IBV) centrifuged on sucrose density gradients was found to consist of a major virus peak of density 1.17 to 1.18 g/cm(3). Three different IBV strains were examined and no morphological differences were detected between virus particles of different densities or from different strains. The polypeptides of the different density virus particles from the three IBV strains were analysed on polyacrylamide gels. In all cases 7 polypeptides were observed, although there were differences in the proportions of these polypeptides in particles of different densities and those from the different strains. The polypeptides have been called VP1 (molecular weight 130,000), VP2 (105,000), VP3 (97,000), VP4 (81,000), VP5 (74,000), VP6 (51,000) and VP7 (33,000). Additional polypeptides were produced if slightly harsher treatments were used.

Haemagglutination by avian infectious bronchitis virus-a coronavirus.

The haemagglutinating ability of three strains of IBV was investigated. It was shown that whereas strain Beaudette had no detectable haemagglutinin, both Connecticut and Massachusetts agglutinated red cells of various species. The haemagglutinin of Connecticut was detectable after sucrose gradient purification whereas that of Massachusetts required both the purification step and incubation with the enzyme phospholipase C to reveal it. The agglutination could be inhibited by specific antisera. Some studies on the nature of the red cell receptor, and the possible presence of a receptor destroying enzyme, are reported.