Mutational screening of APP gene in patients with early-onset Alzheimer disease utilizing mismatched PCR-RFLP

To elucidate the frequency of mutations of the β/A4 amyloid protein precursor (APP) gene in early-onset Alzheimer disease, we designed a mismatched PCR-RFLP that can identify all kinds of missense mutations at codon 717 in addition to the seven kinds of known mutations at exon 17. When we screened mutations at exon 17 utilizing this method and the double missense mutations at exon 16 of the APP gene by PCR-RFLP, no cases revealed mutations of the APP gene among 13 familial and 54 sporadic cases, except one family (OS-1) that had previously been reported and used as a positive control of APP717(Val → Ile). Our results support the hypothesis that mutations in the APP gene are not major causes in early-onset Alzheimer disease.     

Rapid diagnosis of human herpesvirus 6 infection by a novel DNA amplification method, loop-mediated isothermal amplification

A novel nucleic acid amplification method, termed loop-mediated isothermal amplification (LAMP), which amplifies DNA with high specificity, efficiency, and rapidity under isothermal conditions, may be a valuable tool for the rapid detection of infectious agents. LAMP was developed for human herpesvirus 6 (HHV-6), and its reliability was evaluated in this study. Although LAMP products were detected in HHV-6 B and HHV-6 A DNA, they were not detected in HHV-7 and human cytomegalovirus DNA. The sensitivity of the original HHV-6 LAMP protocol was 50 copies/tube. In order to increase the method's sensitivity, HHV-6 LAMP was modified by increasing the primer concentration. As a result of the modification, sensitivity increased to 25 copies/tube. After these initial validation studies, 13 patients with fever were tested for HHV-6 by viral isolation, serological analysis, and HHV-6 LAMP. In three of the eight patients with primary HHV-6 infection, HHV-6 DNA was detected in whole blood by the original HHV-6 LAMP protocol in not only the acute phase but also the convalescent phase. HHV-6 DNA was detected by modified HHV-6 LAMP in all eight plasma samples collected in the acute phase; however, no HHV-6 DNA was detected in plasma samples collected in the convalescent phase. Although HHV-6 DNA was detected in both the acute and convalescent phases of whole-blood samples in patients with past HHV-6 infection, it was not detected in plasma samples that did not contain latent viral DNA. Thus, detection of HHV-6 DNA in plasma by using this modified HHV-6 LAMP protocol is appropriate for diagnosis of active HHV-6 infection.     

Histopathological studies on virulence of dipeptidyl aminopeptidase IV (DPPIV) of Porphyromonas gingivalis in a mouse abscess model: use of a DPPIV-deficient mutant

To elucidate the role of dipeptidyl aminopeptidase IV (DPPIV) in the virulence of Porphyromonas gingivalis, mice were infected with either a wild-type strain or a DPPIV-deficient mutant using an abscess model. Histopathological analysis of the resulting lesions indicated that DPPIV participates in virulence through the destruction of connective tissue and the less effective mobilization of inflammatory cells.     

Production and release of infectious hepatitis C virus from human liver cell cultures in the three-dimensional radial-flow bioreactor

Lack of efficient culture systems for hepatitis C virus (HCV) has been a major obstacle in HCV research. Human liver cells grown in a three-dimensional radial-flow bioreactor were successfully infected following inoculation with plasma from an HCV carrier. Subsequent detection of increased HCV RNA suggested viral replication. Furthermore, transfection of HCV RNA transcribed from full-length cDNA also resulted in the production and release of HCV virions into supernatant. Infectivity was shown by successful secondary passage to a new culture. Introduction of mutations in RNA helicase and polymerase regions of HCV cDNA abolished virus replication, indicating that reverse genetics of this system is possible. The ability to replicate and detect the extracellular release of HCV might provide clues with regard to the persistent nature of HCV infection. It will also accelerate research into the pathogenicity of HCV, as well as the development of prophylactic agents and new therapy.     

Pathogenesis of Rinderpest Virus Infection in Rabbits I. Clinical Signs, Immune Response, Histological Changes, and Virus Growth Patterns

Rabbits were intravenously inoculated with an attenuated rinderpest virus (L strain), and general patterns of the disease were investigated. The rabbits developed fever with concomitant occurrence of diarrhea and lymphopenia. Early production of interferon was followed by a rise of neutralizing antibody. Histological examinations revealed an involvement of all of the lymphoid tissues, with primary lesions consisting of necrosis of the lymphoid follicles and formation of giant cells. Immunofluorescent examinations suggested that the virus growth was present in almost all of the lymphoid tissues. The possibility of application of this experimental system for the study of systemic infection by measles virus was discussed.     

Formation of quinone methide in the self-cure of quinoid phenol formaldehyde resin

The study of the reaction of some methylenebisphenols with chloranil in ethanol and also of a phenol formaldehyde condensate prepared by acid catalysis, reveals that quinone methide is formed in the self-cure of quinoid phenol formaldehyde resin. The quinone methide reacts with ethanol to give an adduct. The structure of the alcohol adduct is identified by NMR and IR data and by means of pyrolysis.     

Propylene Polymerization Behavior of Fluorinated Bis(phenoxy‐imine) Ti Complexes with an MgCl2‐Based Compound (MgCl2‐Supported Ti‐Based Catalysts)

Summary: Fluorinated bis(phenoxy‐imine)Ti complexes 1 – 3 combined with MgCl₂/i‐Bu_nAl(OR)_3−n (MgCl₂‐supported catalysts) were able to polymerize propylene in a living fashion at room temperature to provide slightly to highly syndiotactic poly(propylenes) (PPs) with extremely narrow distributions of molecular weight. These represent the first examples of MAO‐ and borate‐free group 4 metal‐based living catalysts. The supported complexes 2 and 3 formed PPs with higher syndiotacticity and T_m's than the corresponding homogeneous MAO‐activation systems (e.g., 3 : rr 97%, T_m 155 °C; MAO activation: rr 93%, T_m 152 °C). The measured T_m of 155 °C represents the highest known T_m for syndiotactic PPs synthesized at room temperature.

Polymerization of propylene to poly(propylene) with supported Ti‐based catalysts.     

Adherence of Pasteurella multocida or Bordetella bronchiseptica to the swine nasal epithelial cell in vitro.

The interaction of Bordetella bronchiseptica or Pasteurella multocida with swine nasal epithelial cells was studied in vitro. The mean number of B. bronchiseptica organisms adhered per cell was about three times as high as that of P. multocida (P less than 0.01), and the adherence was specifically inhibited by the homologous antiserum prepared with the whole-cell antigen of each bacterium. The poor affinity of P. multocida to the swine nasal mucosa as compared with that of B. bronchiseptica was also demonstrated in the cultured fragments of the nasal mucosa. When observed with a scanning electron microscope, B. bronchiseptica organisms colonized the fragments, whereas few P. multocida organisms adhered. Morphologically, the P. multocida-infected fragments had an essentially normal structure, whereas marked degeneration and marked desquamation of the epithelial cells and severe inflammatory reactions were observed in many areas of the B. bronchiseptica-infected fragments. These morphological observations were consistent with those for the nasal mucosa of P. multocida- or B. bronchiseptica-infected neonatal pigs (T. Nakai, K. Kume, H. Yoshikawa, T. Oyamada, and T. Yoshikawa, Jpn. J. Vet. Sci. 48:693-701, 1986; T. Oyamada, T. Yoshikawa, H. Yoshikawa, M. Shimizu, T. Nakai, and K. Kume, Jpn. J. Vet. Sci. 48:377-387, 1986). Cultured swine nasal fragments, however, were equally injured when they were incubated in a medium containing purified dermonecrotic toxin (DNT) preparations of B. bronchiseptica or P. multocida. Therefore, these DNT preparations can induce morphological damage closely resembling that induced in vivo. Hence, colonization of B. bronchiseptica and production of its DNT on the swine nasal mucosa appear to result in the production of mucosal damage. On the other hand, P. multocida seems to lack the ability to colonize normal swine nasal mucosa, thus resulting in no production or the slight production of DNT to such an extent as to produce mucosal damage. The present data support our previous hypothesis (Nakai et al.; Oyamada et al.) that B. bronchiseptica induces swine atrophic rhinitis, whereas P. multocida does not.