Heterogeneity of the fibre sequence in subgenus C adenoviruses

AIMS

To determine the nucleotide sequences of adenovirus (Ad) types 1 and 6 fibre genes; to clarify the molecular basis of the distinct haemagglutination properties of subgenus C Ads and their phylogenetic relations.

METHODS

Human Ad1 and Ad6 fibre genes were sequenced from genomic DNA by direct sequencing. Primer selection was based on alignment of the fibre gene of human Ad serotypes Ad2 and Ad5. Fibre based subgenus C specific polymerase chain reaction (PCR) was performed to check for deletions in field isolates of Ad6, as revealed by sequence analysis of the Ad6 prototype. A phylogenetic tree was constructed from the predicted amino acid (AA) sequences of the fibre gene of important Ads.

RESULTS

Ad1 and Ad6 comprise 1746 and 1584 nucleotides, encoding 582 and 528 AA, respectively. Ad6 showed deletions in motifs 15-17 (51 AA) of the shaft when compared with Ad1, Ad2, and Ad5. Subgenus C specific PCR with both prototype and field isolates also showed deletions in Ad6. In the shaft and knob, AA homology was 58.82-72.91% and 68.89-74.59%, respectively. The tail was 100% conserved. Phylogenetically, Ad1 and Ad6, including Ad2 and Ad5, formed a subgenus specific cluster, like other serotypes.

CONCLUSIONS

The fibre gene (including the knob region) of subgenus C Ads is heterogeneous, providing the molecular basis for lack of crossreactivity in the haemagglutination inhibition test. This heterogeneity could be helpful in fibre based genotyping of subgenus C field isolates. Phylogeny might be useful for subgenus specific identification of important field strains.

Gallbladder wall thickening associated with infectious mononucleosis

Acute infectious mononucleosis is a typical self-limited lymphoproliferative illness characterized by fever, tonsillar pharyngitis, and lymphadenopathy in adolescents and young adults. Thickening of the gallbladder wall is rarely observed. We report a case of infectious mononucleosis in which marked thickening of the gallbladder wall was detected by ultrasonography and computed tomography.

Serological and genetic characterisation of a unique strain of adenovirus involved in an outbreak of epidemic keratoconjunctivitis

AIMS

To characterise a novel strain of adenovirus (Ad) type Ad8 (genome type Ad8I) involved in an epidemic keratoconjunctivitis (EKC) outbreak in Hiroshima city using serological testing and sequence analysis of the fibre and hexon gene.

METHODS

A neutralisation test (NT) was performed in microtitre plates containing a confluent monolayer of A549 cells using 100 tissue culture infectious doses of virus and type specific antisera. The haemagglutination inhibition test was also carried out in microtitre plates with rat erythrocytes using four haemagglutination units of virus and twofold dilutions of serum. The fibre gene was sequenced by generating overlapping polymerase chain reaction products or by direct sequencing of genomic DNA. Primer selection was based on alignment of the fibre genes of human adenovirus serotypes Ad8, Ad19, Ad37, Ad9, and Ad15 available from Gene Bank.

RESULTS

The virus strain was specifically neutralised by anti-Ad8 antibodies, although there was a major crossreaction with anti-Ad9 antibodies. Haemagglutination was equally inhibited by anti-Ad8 and anti-Ad9 antibodies. The predicted amino acid sequences of the hypervariable regions (HVRs) of the Ad8I hexon gene showed higher homology with Ad9 (83.3%) than with Ad8 (62.0%). However, the Ad8I fibre knob was more homologous to Ad8 (94.4%) than to Ad9 (91.6%).

CONCLUSIONS

Ad8I is a unique strain of adenovirus because of its lower genomic homology with Ad8, major crossreactivity with Ad9 in NT, and mixed genetic organisation of HVRs of the hexon gene. These factors may have enabled the virus to circumvent acquired immunity, resulting in the outbreak.

Characterisation of hexon and fibre genes of a novel strain of adenovirus involved in epidemic keratoconjunctivitis

AIMS

To characterise a novel strain (M86) of adenovirus (Ad) involved in epidemic keratoconjunctivitis (EKC).

METHODS/RESULTS

The virus strain was neutralised by antisera to both Ad35 and Ad11. Restriction endonuclease analysis of genomic DNA showed 98% and 88% homology with Ad11 and Ad35, respectively. The deduced amino acid sequence of the hypervariable regions of (HVRs) of the hexon gene showed a higher homology with Ad35 (94.4%) than with Ad11 (83.7%). However, it was 100% homologous to Ad35 in HVRs 1, 2, 3, and 6 and to Ad11 in HVRs 4 and 6. In the fibre knob, the isolate was more homologous to Ad11 (99.4%) than to Ad35 (29.1%).

CONCLUSION

This novel strain of adenovirus showed similarities with both Ad11 and Ad35. The isolation of a novel strain like Ad35+11 is important because of its association with EKC.

Genetic characterisation of adenovirus type 8 isolated in Hiroshima city over a 15 year period

AIMS

To investigate the genetic differences among the strains of adenovirus type 8 (Ad8) circulating in Hiroshima city, Japan, and to study their circulation pattern.

METHODS

One hundred and twenty nine strains of adenovirus type 8 (Ad8) were isolated in Hiroshima City over a 15 year period (1983-97) from patients with keratoconjunctivitis, and analysed with six restriction enzymes-BamHI, HindIII, PstI, SacI, SalI, and SmaI-to investigate possible relations among the isolates and their genetic variability. Seven hypervariable regions of the hexon gene that carry the type specific epitope were also sequenced to investigate the variation among the genome types.

RESULTS

Restriction endonuclease analyses yielded three known genome types (Ad8A, 13 samples; Ad8B, seven samples; and Ad8E, 35 samples) and a novel genome type (Ad8I, 74 samples). Ad8A, Ad8B, and Ad8E were closely related, with 96% homology, whereas Ad8I had only 71% homology. Ad8A, Ad8B, and Ad8E shared 91.8% and 96.4% homology with regard to their amino acid and nucleotide sequences, respectively, with the isolate 1127 (accession no X74663). However, when compared with Ad8A, Ad8B, Ad8E, and isolate 1127, Ad8I shared only 62.7% and 69.9% homology with regard to amino acid and nucleotide sequences, respectively. Ad8A, Ad8B, and Ad8E had a unique 31 amino acid deletion in the hypervariable region 1 of the hexon gene, whereas Ad8I had a 33 residue deletion. The Ad8E strain that circulated from 1984 to 1995 was stable among the study population. Ad8I was isolated from an outbreak of epidemic keratoconjunctivitis in 1995 and was also isolated from sporadic cases until 1997.

CONCLUSIONS

These results confirmed that genetic variability occurs in Ad8 in the microenvironment and revealed the emergence of a new genome type (Ad8I).

Use of antiserum-coated latex particles for serotyping Streptococcus pneumoniae

The Quellung reaction provides a standard means for serotyping Streptococcus pneumoniae, but it requires microscopic examination with skillful technique. We have developed an improved agglutination method with anti-rabbit IgG-coated latex particles, which are sensitized with pooled antisera for serotyping/serogrouping S. pneumoniae. Our method is as specific and sensitive as the Quellung test, and much easier to perform.

Evaluation of a mass influenza vaccination campaign

Kawaura, a rural town in Kumamoto Prefecture, Japan, population approximately 6,800, started a mass influenza vaccination campaign in the 1999-2000 season for all residents > or = 3 years of age. The town provided free vaccinations to children < or = 13 years and the elderly > or = 65 years. Only 900 yen (US$8.80) was charged to the other residents for two vaccinations. In the 1999-2000 season, a total of 5,563 doses of vaccine were administered to 2,952 residents. Over 90% of the vaccinees received two doses. The program resulted in a vaccination rate of 43% of all residents. The vaccination rates for females and males were 40.7% and 36.8%, and for those of 3-14 years, 15-64 years, and > or = 65 years population were 75%, 31%, and 55%, respectively. The town spent a total of 5.78 million yen (US$56,700) for the campaign. The per-shot cost was estimated as 1,683 yen (US$16.50). From December 1999 through March 2000, a total of 233 town residents (15-101 years old, median 72) were admitted to the town hospital. Of the 233 inpatients, 22 (66-98 years old, median 78) developed respiratory illness, with 4 fatal outcomes. Of these 22 cases, 3 had been vaccinated twice, while 19 had not been vaccinated at all. The relative risk of vaccinees' hospitalization due to respiratory illness decreased to 0.13 compared with that of non-vaccinees (3/1,203 versus 19/1,003, vaccine efficacy = 0.87). Likewise, the relative risk of vaccinees death due to respiratory illness decreased to 0.28 compared with that of non-vaccinees (1/1,203 versus 3/1,003). The results of the Kawaura town's initiative should be helpful for better modeling of mass influenza vaccination campaigns.

[Field epidemiological investigation on an outbreak of Chlamydia pneumoniae infection--first recognized incidence in a nursing home for elderly in Japan]

Chlamydia pneumoniae (C. pneumoniae) is an emerging pathogen recognized in 1989. Although C. pneumoniae infection is known to give a great impact on public health in western countries, many aspects remain unclarified in Japan. During December 1999 and March 2000, respiratory symptoms among residents and employees in a nursing home for elderly implicated an outbreak of C. pneumoniae infection. Field epidemiological investigation confirmed that this is the first outbreak recognized in a nursing home setting in Japan, involving 31/59 (15 confirmed) residents and 9/41 (2 confirmed) employees. Fifteen residents developed severe C. pneumoniae infections including one fatal outcome with pneumonia. Epidemiological analysis did not identify risk factors which induce infection or severe illness by C. pneumoniae for the residents. However, for the employees, frequent contact with the residents was demonstrated as a significant risk factor for the infection. None of 13 employees who had no contact with the residents presented C. pneumoniae infection, while nine out of 28 employees who had frequent contact developed C. pneumoniae infections (RR infinite, P = 0.04). These results indicated that C. pneumoniae infection spread gradually by human-to-human droplet transmission without specific risk factors. This study raised current problems in diagnosing and treating the C. pneumoniae infection and the need to enhance the awareness of this disease.

Comparative analysis of host responses related to immunosuppression between measles patients and vaccine recipients with live attenuated measles vaccines

Measles virus infection induces a profound immunosuppression. We analyzed in a time-dependent manner peripheral bloods of one to two-year-old children immunized with live attenuated measles vaccines, compared with age-matched measles patients, for immunosuppression. In contrast to transient severe lymphopenia with measles patients, primarily due to extensive apoptosis of a broad spectrum of uninfected lymphocytes, neither apoptosis nor lymphopenia occurred with measles vaccine recipients. Increase in number and activation of NK cells, which might compensate for the lymphopenia in measles patients, were not found with the vaccinees. While cell surface expression of apoptosis-related molecules such as TNF-related apoptosis-inducing ligand (TRAIL), TRAIL-receptors, CD95(Fas) and Fas-ligand, and plasma interferon-gamma were increased for measles patients, they remained unchanged after vaccination. Plasma interleukin (IL)-18, which is responsible for inducing apoptosis in several infectious diseases, was increased predominantly with measles patients, whereas the increase remained marginal with the vaccinees. IL-10 was elevated transiently in both measles patients and vaccinees. Decrease in plasma IL-12, which is often correlated with T cell suppression, was not found for both cases. Serum IgM and IgG antibodies to measles virus were induced at lower titers in the vaccinees than measles patients. These results indicate that in contrast to wild-type measles virus, live measles vaccines hardly provoked host cytokine responses that lead to apoptotic cytolysis of uninfected lymphocytes, lymphopenia and immunosuppression, and thereby induced weaker immune responses to the virus.

The pathogenesis of Crohn's disease

Although much progress has been made in understanding the pathogenesis of Crohn's disease, the precise etiology of Crohn's disease still remains unknown. In our serial studies on Crohn's disease, we found a decrease in NK and ADCC activities as well as a decrease in the phagocytic activity by monocytes, whereas an increased superoxide production activity by monocytes was evident. On the other hand, the characterization of lymphocyte subsets has demonstrated no abnormalities. According to these findings, I would like to propose a new tentative hypothesis for the pathogenesis of Crohn's disease. It has been suggested that impaired killing system activities, such as phagocytic as well as NK and ADCC activities, are primarily responsible for the promotion and perpetuation of chronic inflammation and ulceration. When our attention is directed to the common target substances of these protective mechanisms, viral antigens appear as the most likely causative organism. Therefore, a lot of attention must be focused on viral infection as a causative factor. Furthermore, effects of psychological and physical stress on the disease onset or the recurrence of inflammatory bowel disease are also discussed.

Analysis of Japanese encephalitis epidemic in Western Nepal in 1997

We conducted an epidemiological study of a Japanese encephalitis (JE) outbreak in the southwestern part of Nepal in 1997. A high density of JE infections was found and it was estimated that 27.9% the total population were infected with JE virus in the study area. The fatality rate was 13.2% and there was no difference in the fatality rate between males and females over 5 years old. However, the case fatality rate was 2.1 times higher in females than in males (14.6% vs. 6.9%) among children under 5 years of age. Fifty-three blood samples were collected from suspected JE cases during the epidemic period in 1998. Findings for JE specific IgM revealed that clinical diagnoses of JE were serologically confirmed in an average 78% (70-93%) of patients in three collaborating hospitals. These studies demonstrated that JE was highly prevalent in the area and clinical diagnoses were reliable. Effective preventive measures should be taken against this vaccine-preventable disease.

Bis(mu-pyridine-2,6-carboxylato-O,N, O':O)bis[triaquamanganese(II)]-pyridine-2,6-dicarboxylic acid (1/2)

In the structure of the title compound, [Mn(2)(C(7)H(3)NO(4))(2)(H(2)O)(6)].2C(7)H(5)NO(4), a centrosymmetric dinuclear complex, hexaaaquabis(pyridine-2, 6-dicarboxylato)dimanganese(II) and free pyridine-2,6-dicarboxylic acid are present in a 1:2 ratio. In the complex, each Mn(2+) ion is coordinated by three O atoms and one N atom from the pyridine-2, 6-dicarboxylate ligands and by three water O atoms, resulting in a distorted pentagonal bipyramidal coordination. Within the centrosymmetric dinuclear complex, two Mn(2+) ions are bridged by two carboxylate O atoms. The crystal structure is stabilized by hydrogen bonds involving all the H atoms of the water ligands.

Ankycorbin: a novel actin cytoskeleton-associated protein

BACKGROUND

Actin cytoskeleton structures are essential for a wide variety of cell functions, including cell shape change, cell motility, cell adhesion, cell polarity and cytokinesis. Many actin filament (F-actin)-binding proteins have been isolated and implicated in the maintenance and reorganization of actin cytoskeleton structures.

RESULTS

We purified here a novel protein with a molecular mass of about 125 kDa (p125) from rat liver. We cloned its cDNA from a mouse kidney cDNA library and determined its nucleotide and deduced amino acid sequences. p125 was a protein of 979 amino acids with a calculated Mr of 108 847. p125 contained six ankyrin repeats in the N-terminal region and a domain predicted to form a coiled-coil structure in the C-terminal region. We named p125 ankycorbin (ankyrin repeat- and coiled-coil structure-containing protein). Northern blot analysis indicated that ankycorbin was ubiquitously expressed in all the tissues examined. Immunofluorescence and immunoelectron microscope analyses revealed that ankycorbin was associated with the cortical actin cytoskeleton structures in terminal web and cell-cell adhesion sites and stress fibres. However, ankycorbin did not directly bind to F-actin as estimated by the F-actin co-sedimentation assay.

CONCLUSIONS

These results indicate that ankycorbin is indirectly associated with the actin cytoskeleton structures, presumably through an unidentified factor and suggest that it is involved in their maintenance and/or reorganization.

catena-Poly[[diaqualithium(I)]-mu-[9H-purine-2,6(1H, 3H)-dionato-O2:N7]]

In the title compound, [Li(C(5)H(3)N(4)O(2))(H(2)O)(2)](n), the coordinate geometry about the Li(+) ion is distorted tetrahedral and the Li(+) ion is bonded to N and O atoms of adjacent ligand molecules forming an infinite polymeric chain with Li-O and Li-N bond lengths of 1.901 (5) and 2.043 (6) A, respectively. Tetrahedral coordination at the Li(+) ion is completed by two cis water molecules [Li-O 1.985 (6) and 1.946 (6) A]. The crystal structure is stabilized both by the polymeric structure and by a hydrogen-bond network involving N-H.O, O-H.O and O-H.N hydrogen bonds.

Association of Helicobacter pylori infection with atrophic gastritis and intestinal metaplasia

AIMS

To evaluate the effect of Helicobacter pylori infection and aging on atrophy and intestinal metaplasia of the gastric mucosa.

METHODS

One hundred and sixty-three patients were divided into three age groups and underwent an upper gastrointestinal endoscopy where no esophagitis, peptic ulcers, or malignancies were detected. Two biopsy specimens were obtained from the anterior and posterior walls of the antrum and of the fundus. These were used to evaluate the grade of gastritis, bacterial culture and histologic evidence of H. pylori infection.

RESULTS

Helicobacter pylori infection was found to be directly associated with an increased risk of gastritis grade (odds ratio (OR) = 90 (95% CI; 30-270)). An age of 60 years and older along with H. pylori infection was also strongly associated with an increased risk of atrophy (OR = 6.6, (95% CI; 2.9-15.2)); OR = 9.8, (95% CI; 2.7-35.4)), as was intestinal metaplasia of the gastric mucosa (OR = 5.5, (95% CI; 1.7-17.6)); OR = 7.9, (95% CI; 2.8-46.1)). The prevalence of atrophic gastritis increased with advancing age in H. pylori-infected patients, but no such phenomenon was observed in H. pylori-uninfected patients. The prevalence of intestinal metaplasia significantly increased with advancing age, irrespective of the presence of H. pylori infection. In addition, H. pylori uninfected female patients had a decreased risk of intestinal metaplasia.

CONCLUSIONS

These results suggest that atrophic gastritis is not a normal aging process, but instead is likely to be the result of H. pylori infection, while intestinal metaplasia is caused by both the aging process and H. pylori infection. A decreased risk of intestinal metaplasia found in uninfected female subjects may partly explain the lower prevalence of gastric cancer in females than in males.

Surveillance of viral gastroenteritis in Japan: pediatric cases and outbreak incidents

Surveillance results from pediatric cases and outbreaks of viral gastroenteritis in Japan are presented. In winter, both small round structured virus (SRSV, or Norwalk-like viruses) and rotavirus were detected from infants with gastroenteritis; however, in recent years, the prevailing time of SRSV infection has preceded that of rotavirus infection. Most nonbacterial gastroenteritis outbreaks were related to SRSV infection, and >60% of the outbreaks were caused by contaminated food. In small-sized outbreaks, raw oysters were the primary source of transmission. In large-sized outbreaks, school lunches and catered meals that were served at schools, banquet halls, and hospitals were most often implicated in the transmission of foodborne gastroenteritis.

Influenza surveillance system of Japan and acute encephalitis and encephalopathy in the influenza season

AIM

To understand the situation of influenza epidemics and neurologic complications during the influenza season in Japan.

METHODS

The influenza surveillance system in Japan was reviewed and the data on influenza/influenza-like illness and neurologic complications, such as acute encephalitis/encephalopathy, were evaluated.

RESULTS

From the data of the National Epidemiological Surveillance of Infectious Diseases (NESID), an increase in clinically diagnosed encephalitis/encephalopathy was clearly noted recently. Most cases reported were acute encephalitis/encephalitis. The number of cases of Reye's syndrome reported was stable and low in number, since the time of the recommendation of not using aspirin for pediatric febrile disease, particularly for influenza-like illness, in Japan. These acute encephalitis/encephalopathy cases were not correlated clearly with clinically diagnosed influenza patients before the 1997/98 influenza season from the surveillance data, although several case reports have shown a relationship.

CONCLUSIONS

It is clarified from the NESID that neurologic complications such as acute encephalitis/encephalopathy, apart from Reye's syndrome, have occurred associated with influenza virus infection, especially among young children. Further investigation should be necessary to find the pathogenesis of this serious complication of influenza virus infection and whether this is unique in Japan, due to unclarified factor/factors, or whether it has not been recognized in other countries.

[Current topics of acute encephalitis and encephalopathy: introductory remarks]

Encephalitis/encephalopathy is a neurological syndrome characterized by acute onset, symptoms of intracranial hypertension accompanying severe sequels or death. Encephalitis is caused by microbial infection of central nervous system, such as neurotrophic or conventional viruses. Infectious encephalopathy shows similar clinical symptoms to acute encephalitis, without any evidence of inflammation and microbial infection in brain tissues. The national epidemiological surveillance of the diseases is carried out to study the frequency and prognosis of patients with both diseases. The principal treatment is quite different in the both, in the former the eradication of microbial from the brain and in the latter the reduction of pressure of brain edema. Furthermore, the improvement of the brain with severe destruction requires such new step to reduce the activities of enzymes or cytokines to destroy brain tissues, as a mild hypothermia to lower body and brain temperature to 33-34 degrees C.

[Epidemiology--surveillance information]

Recent data of the National Epidemiological Surveillance of Infectious Diseases (NESID) showed that neurological complications associated with influenza virus infection, such as acute encephalitis/encephalopathy (excluding Reye's syndrome) have increased in number especially among young children. Further investigation is necessary to find the pathogenesis of these serious complications and clarify whether this phenomenon is due to unclarified factor(s) unique in Japan or it has reminded unrecognized in other countries.