Age-related alterations in adenylyl cyclase system of rat hearts.

Cardiac membranes from 26-, 52- and 104-week-old Wistar rats were used to investigate the age-related alterations in the beta-adrenergic receptor-adenylyl cyclase system. The densities and affinities of beta-adrenoceptors did not change with aging. There were no significant changes in the total amount of stimulatory G-protein (Gs), and in Gs activity measured in a reconstitution assay using human platelet membranes. The major isoform of Gs alpha, however, changed from a 45,000 to 52,000 dalton peptide with aging. The total amount of pertussis toxin substrates (Gi2 and Go) decreased significantly with aging. This finding was supported by the fact that pertussis toxin-induced potentiation of adenylyl cyclase activity was markedly reduced in the aged group. The activity of catalytic protein assessed by forskolin-stimulated adenylyl cyclase activity was decreased at 104 weeks. On the other hand, GTP analogue-stimulated adenylyl cyclase activity was significantly potentiated in the same group. These results suggest that the decreased sensitivity to catecholamines observed in aged hearts is mainly due to a dysfunction of catalytic protein, and that decreased Gi activity partially compensates for this catalytic dysfunction.     

Identification of human and bovine rotavirus serotypes by polymerase chain reaction.

The use of the polymerase chain reaction (PCR) for identifying serotypes of human and bovine rotaviruses was examined. In the identification of 115 human rotavirus samples in stools, results with PCR showed excellent agreement with results of serotyping by an enzyme-linked immunosorbent assay (ELISA) using serotype-specific monoclonal antibodies. Furthermore, the PCR showed a much higher sensitivity (93%) than the ELISA test (82.6%). The PCR method could also be applied for identifying the serotype of bovine rotaviruses.     

Seasonal variation in sweating responses of older and younger men

Eight older (60–65 years) and six younger (20–25 years) men were exposed to a standard heat stress for 60 min in summer, autumn, winter, and spring. The test consisted of placing the lower legs and feet in a 42°C water bath while sitting in constant environmental conditions (30°C and 45% relative humidity). The increase of rectal temperature (T _re) was significantly greater (P < 0.05) in autumn, winter, and spring than in summer for the older group, but significantly greater only in winter than in summer for the younger group (P < 0.05). The T _re was greater for the older group in all seasons, but of significance only in autumn and spring (P < 0.01). There were no significant season-related differences for metabolic heat production (m) and mean skin temperature ( _sk) during the heat test in the respective groups, although the m and _sk were lower for the older group in all seasons (P < 0.01). In the older group total body sweating rate (m_sw) divided by T _re (total m_sw/T _re) decreased from summer to winter (P < 0.02) and did not differ between winter and spring, whereas total m_sw/T _re in the younger group increased in spring after decreasing from autumn to winter (P < 0.03). The variations of the value, local sweating rate on the back and thigh divided by T _re (back m_sw/T _re and thigh m_sw/T _re), were similar to those of the total m_sw/T _re in each group, except for back m_sw/T _re in the younger group, which did not increase from winter to spring. The total m_sw/T _re, back m_sw/T _re and thigh m_sw/T _re were significantly less for the older group in summer, autumn and spring (P < 0.05). The range of seasonal variations was significantly less for the older group (P < 0.001). The results indicated that, compared with younger men in older men, the enhancement of sweating function toward summer occurred later and its reduction toward winter occurred earlier despite a smaller range of seasonal variation and that older men had a somewhat lesser capability to maintainT _re when challenged by heat stress in all seasons.     

Characterization of a G14 equine rotavirus (strain CH3) isolated in Japan

Summary Antigenic and genomic properties of equine rotavirus strain CH3 isolated in Japan were studied by cross-neutralization tests and nucleotide sequence determination of the VP4 and VP7 genes. It was shown that the strain CH3 belongs to G14 and shares VP4 genotype with strain H2.The nucleotide sequence data reported in this paper appear in the DDBJ, EMBL and GeneBank nucleotide sequence detabases under the accession numbers D25228 (VP4 of strain CH3) and D25229 (VP7 of strain CH3).     

Reactivity patterns to human rotavirus strains of a monoclonal antibody against VP2, a component of the inner capsid of rotavirus

Summary A non-neutralizing monoclonal antibody (YO-60) against human rotavirus was found to be directed to VP2 (90,000-dalton protein), one of the two major components of the inner capsid. The reactivity patterns of the YO-60 antibody were very similar, though not identical, to those of subgroup II-specific YO-5 monoclonal antibody directed to VP6 (42,000-dalton protein), the other major component of the inner capsid.These results indicated the possible presence of a subgroup-specific antigen on VP2 in addition to the one on VP6.With 1 FigureThis study was supported in part by a grant no. 58570213 from the Ministry of Education, Science and Culture of Japan.     

Analysis of human rotavirus strains prevailing in Bangladesh in relation to nationwide floods brought by the 1988 monsoon.

The virologic character of human rotavirus strains prevailing in Bangladesh was investigated in relation to the devastating nationwide floods brought by the 1988 monsoon. Human rotaviruses contained in stool specimens that were collected from inpatients with infantile and adult diarrhea in two hospitals in Mymensingh over a 13-month period (January 1988 to January 1989) and in one hospital in Dhaka over a 3-month period (February to April 1988) were examined for their subgroup, VP7 serotype, and RNA electropherotype. In concurrence with the spread of the flood (from the middle of August 1988), the number of infantile and adult diarrhea patients increased greatly. At the same time, the proportion of rotavirus-positive specimens in all diarrhea cases also increased remarkably, reaching 54 and 45% in September and October, respectively. An electrophoretic analysis of viral RNA revealed 17 distinct patterns of viral RNA (14 long and 3 short electropherotypes) and a considerable number of mixed electropherotypes, suggesting the simultaneous infection of some patients with more than two rotavirus strains. It was noteworthy that electropherotypes of rotavirus strains prevailing in the community changed considerably after the spreading of the flood and that the frequency of virus specimens showing mixed electropherotypes increased significantly during the flood period. These results suggest that sudden environmental change caused by the devastating floods seriously affected the epidemiology of rotavirus infections by increasing the opportunity of transmission of the virus and by reducing the resistance of the host to infection. In both pediatric and adult patient groups, serotypes 1 and 2 were the most frequent ones detected, followed by serotype 4.(ABSTRACT TRUNCATED AT 250 WORDS)     

Operational overlapping of cross-reactive and serotype-specific neutralization epitopes on VP7 of human rotavirus serotype 3

Summary VP7-specific neutralizing monoclonal antibodies (N-MAbs) to serotype 3 human rotavirus were produced to analyze serotype 3-specific and cross-reactive neutralization epitopes on VP7. On the basis of the reactivity patterns in neutralization tests with various human and animal strains, a total of 10 N-MAbs could be classified into four groups; five antibodies specific to serotype 3 were divided into two groups, and five antibodies consisted of two groups which are cross-reactive with strain 69M (serotype 8) or strain WI61 (serotype 9). Seven N-MAbs showed the same reactivity patterns to the virus strains in both neutralization tests and enzyme-linked immunosorbent assay (ELISA), while three N-MAbs specific to serotype 3 in neutralization showed a cross-reactivity with the serotype 8 strain in ELISA. Neutralization-resistant mutants of serotype 3 strains P and YO were selected by the N-MAbs. Cross-neutralization tests between the mutants and the MAbs indicated the presence of two serotype-specific (S1 and S2) and three cross-reactive (C1, C2, and C3) epitope groups. S1, S2, and C3 epitope groups overlapped operationally each other, and the S1 epitope group had an overlapping with the C1 epitope group. However, C2 epitope group identified by the MAbs which neutralized serotypes 3 and 9, had no operational overlapping with any other epitope groups.     

Antigenic and genetic analyses of human rotavirus with dual subgroup specificity.

In our previous study (S. Urasawa, T. Urasawa, K. Taniguchi, F. Wakasugi, N. Kobayashi, S. Chiba, N. Sakurada, S. Morita, O. Morita, M. Tokieda, T. Kawamoto, K. Minekawa, and M. Oseto, J. Infect. Dis. 160:44-51, 1989) of antigenic characterization of about 300 human rotavirus (HRV) isolates collected at different localities in Japan, we found 4 HRV isolates having unique antigenic and genetic constructions. The four strains possessed both subgroup I and subgroup II antigens, serotype 3 antigen, and a long RNA electropherotype. The reactivity pattern of these four HRV isolates with three monoclonal antibodies (MAbs) directed to an outer capsid protein, VP4, and with one MAb directed to an inner capsid protein, VP2, was clearly different from those of usual subgroup II HRVs having serotype 1, serotype 3, or serotype 4 specificity and a long RNA pattern, whereas their reactivity pattern was similar to that of strain K8 (subgroup II, serotype 1), which possessed unique VP4 and VP2 proteins. RNA-RNA cross-hybridization analysis indicated that while the four isolates were genetically distinct from the two genetic groups of HRV reported previously, i.e., the Wa family (strains KU, S3, and YO) and the DS-1 family (strain S2), they were closely related to strain K8, a strain having unique antigenic and genetic properties (K. Taniguchi, K. Nishikawa, T. Urasawa, S. Urasawa, K. Midthun, A. Z. Kapikian, and M. Gorziglia, J. Virol. 63:4101-4106, 1989).     

Characterization of factor XII Tenri, a rare CRM-negative factor XII deficiency

Factor XII Tenri (Y34C), a rare cross-reacting material (CRM)-negative factor XII deficiency, was identified in a 71-yr-old Japanese woman with angina pectoris. In the patient's plasma, factor XII activity and antigen levels were only 1.6% and 5.0%, respectively, of those seen in a normal subject. Immunoblot analysis showed that the secreted factor XII Tenri existed not only as a monomer (76 kDa), but also in complexes with apparent molecular weights of approximately 115, 140, 190, 215, and 225 kDa. After reduction with 2-mercaptoethanol, the factor XII Tenri contained in the complexes was completely converted to monomeric form on immunoblot patterns. It appeared that some of the secreted factor XII Tenri formed several types of disulfide-linked complexes, including a factor XII-alpha1-microglobulin complex, through a newly generated Cys residue. The monomeric form of factor XII Tenri, like normal factor XII, was degraded into 2 major fragments with molecular weights of approximately 45 kDa and 30 kDa following mixing with activated partial-thromboplastin-time measuring reagent (cephalin and ellagic acid), whereas the factor XII Tenri that formed the complexes was not. This indicates that the factor XII Tenri present in disulfide-linked complexes with other proteins (and itself) is not converted to active forms, suggesting that attached proteins obstruct or delay the activation of factor XII via an inhibition of its binding to a negatively charged surface in vitro.     

Analysis of genomic diversity within the Xr-region of the protein A gene in clinical isolates of Staphylococcus aureus.

Protein A of Staphylococcus aureus contains a polymorphic Xr-region characterized by a tandem repeat of eight amino acid units. In this study, the diversity of genes encoding the repeat regions and their relatedness among S. aureus strains was analyzed. Ten different protein-A types characterized by repeat numbers 4-13 were identified in a total of 293 clinical isolates. The protein-A type with 10 repeat units (10 repeats) in the Xr-region was most frequently detected in methicillin-resistant S. aureus, whereas the majority of methicillin-susceptible strains were distributed almost evenly into protein-A types with 7-11 repeats. Strains that belonged to a single coagulase type were classified into multiple protein-A types, e.g. strains with the common coagulase types II and VII were differentiated into 7 and 8 protein-A types, respectively. Nucleotide sequence analysis of the Xr-region of 42 representative strains revealed the presence of 37 different genotypes (spa types), which were constituted by a combination of several of 24 different repeat unit genotypes. Based on the similarity in arrangement of repeat unit genotypes, 34 strains with different repeat numbers were classified into 5 genetic clusters (C1-C5). The clusters C1, C2 and C3 consisted exclusively of strains with identical coagulase types II, III, and IV, respectively. These findings suggested that the protein-A gene of S. aureus has evolved from a common ancestral clone in individual clusters independently.