bluuebunny/crossref_metadata_2025 huggingface dataset:
Distribution of three major hepatitis C virus genotypes in Italy. A multicentre study of 49 5 patients with chronic hepatitis C
Authors: Pontisso P. , Ruvoletto M. G. , Nicoletti M. , Tisminetzky S. , Gerotto M. , Levrero M. , Artini M. , Baldi M. , Ballardini G. , Barbara L. , Bonetti P. , Brillanti S. , Casarin C. , Chemello L. , Costanzo A. , Mitri M. S. De , Donada C. , Felaco M. F. , Frezza M. , Gaeta G. B. , Giostra F. , Iervese T. , Iacono O. Lo. , Milella M. , Monno L. , Negro F. , Piccinino F. , RUSSO G. , Vaccaro A. , Baralle F. , Alberti A.
Published: December 2007

SUMMARY. Different genotypes of hepatitis C virus (HCV) have been shown to have distinct geographical distribution and to associate with variable clinical features. To evaluate their role in chronic hepatitis in Italian patients, we studied 495 consecutive cases with chronic hepatitis C seen in nine sentinel centres homo geneously distributed over Italy. HCV genotyping was carried out using a dot‐blot hybridization assay with genotype‐specific probes. Four hundred and eleven patients were viraemic and could be evaluated: 57% were found to be infected with HCV‐1,31% with HCV‐2, 8% with HCV‐3. 1% showed mixed infection and 3% were ascribed to HCV‐2b or HCV‐4 by direct sequencing. Geographical distribution showed discrete territorial variations. A history of drug addiction was commoner in patients infected with HCV‐3. There were no signifi cant differences in activity of liver disease among different HCV genotypes but the response to interferon therapy was reduced in patients infected with HCV‐1 compared to HCV‐2 or HCV‐3.
Hepatitis B virus replication‐an update
Authors: Nassal M. , Schaller H.
Published: December 2007

Summary. Hepatitis B virus (HBV), the causative agent of type B hepatitis in humans, is the prototypic member of the hepadnaviridae, a family of small enveloped DNA‐containing viruses with pronounced host and tissue specificity. This property has greatly hampered progress in understanding the initial events of infection, i.e. attachment, penetration and uncoating. After the discovery, originally made with the duck hepatitis B virus (DHBV), that hepadnaviruses replicate by reverse transcription, DNA transfection of cloned wild‐type and mutant HBV genomes into cell lines supporting virion formation has revealed the molecular mechanisms of the late steps of the infectious cycle in some detail. During the last few years, such studies have emphasized the differences between hepadnaviral and retroviral replication. Very recent research, however, indicates that the border separating the two viral families may not be as strict as previously thought. In this article, we will briefly summarize the pertinent differences, and will then focus on the new data, with particular emphasis on the initiation of reverse transcription.
Long‐term productive episomal hepatitis B virus replication in primary cultures of adult human hepatocytes infected in vitro
Authors: Rumin S. , Gripon P. , Seyec J. Le , Corral‐Debrinski M. , Guguen‐Guillouzo C.
Published: December 2007

Summary. We have previously increased the efficiency of hepatitis B virus (HBV) infection of human hepatocytes in vitro by using polyethylene glycol. After further documenting by neutralization experiments, this in vitro infection, we used this model to define new culture conditions that would maintain stable episomal replication for several weeks. We found that in the presence of 10% porcine serum and 2% dimethyl sulphoxide (DMSO), high‐density cultures survived more than 3 months, while addition of hydrocortisone instead of DMSO resulted in survival of less than 1 month. HBV episomal replication was maintained without any evidence of viral integration into the host genome. The maintenance of HBV replication was demonstrated by: first, stability of the covalently‐closed‐circular DNA in the nucleus and relaxed circular and single‐stranded replicative intermediates in the cytoplasm; second, detection of two major transcripts of 3.5 and 2.1–2.4 kb corresponding to the pregenomic and surface genes respectively; and third, continuous secretion of mature viral particles in the supernatant of infected cells. We showed that under these culture conditions, hepatocytes were blocked in the G1 phase of the cell cycle and did not spontaneously proliferate. Upon hepatocyte growth factor (HGF) stimulation, however, the ability of hepatocytes to divide was demonstrated and was compared in infected and non‐infected cells. No change in proliferative capacity and no variation in c‐myc and c‐jun levels could be found. Hepatocyte survival was not modified in infected cells, confirming that HBV is not cytopathic for normal human hepatocytes. These new culture conditions represent substantial progress in the study of HBV‐host cell interactions.
Autoimmunity in hepatitis C and D virus infection
Authors: Strassburg C. P. , Obermayer‐Straub P. , Manns M. P.
Published: December 2007

SUMMARY. A large number of viruses are capable of inducing acute or chronic hepatitis. The syndrome of chronic hepatitis encompasses not only viral but also autoimmune liver diseases. The hepatitis C virus, and recently also the hepatitis D virus have been found to be associated with an array of autoimmune syndromes, diseases and markers of autoimmunity. The relationship of hepatotropic virus infection and the immune system leading to virus‐associated autoimmunity, and its distinction from genuine autoimmune disease represents a fascinating field of research. Clinically, the differentiation between autoimmune liver diseases, virus infection and virus‐associated autoimmunity is difficult and epidemiological evaluations have not come up with universally applicable and valid classification criteria. However, both autoimmune liver diseases and viral hepatitis can readily be diagnosed and distinguished through precise and molecularly determined immunological testing systems. The overlap of both, virus‐associated autoimmunity, is still at the centre of research activities aimed at establishing diagnostic and risk‐assessment criteria. Studies of molecular autoantigens and autoepitopes have begun to define the differences of the B‐cell response in autoimmune disease and virus‐associated autoimmunity. This provides data that may contribute to the safe application of therapeutic strategies as different as immunosuppression and interferon‐α (IFN‐α). The present review focuses on the clinical, epidemilogical and molecular aspects of these disease entities.
Fluctations in viral load (HCV RNA) are relatively insignificant in untreated patients with chronic HCV infection
Authors: Nguyen T. T. , Sedghi‐Vaziri A. , Wilkes L. B. , Mondala T. , Pockros P. J. , Lindsay K. L. , McHutchison J. G.
Published: December 2007

SUMMARY. A recently available assay to quantify serum viral load in hepatitis C virus (HCV) infection has been used to evaluate the effects of anti‐viral therapies. However, variability in HCV RNA levels in untreated patients with HCV infection has not yet been established. We therefore prospectively measured the biological fluctuations of HCV RNA in sera from untreated patients with chronic HCV infection. Sera were collected from seven patients at 8 am and 4 pm on the same day to assess the effect of diurnal variation, daily for 5 days in a further 10 patients, biweekly for 6 weeks in nine patients and monthly for 3 months in 11 patients. All patients had biopsy‐proven chronic liver disease with elevated alanine aminotransferase (ALT) values and had not received anti‐viral treatment. HCV RNA was measured blinded, in duplicate, using the quantitative branched (bDNA) amplification assay (Quantiplex™ HCV RNA. Chiron Co. Erneryville. CA) 36 of the 37 patients studied had measurable HCV RNA throughout the study. There was no significant correlation between HCV RNA levels and ALT values or histological activity. HCV RNA levels did not appear to vary significantly within any of the groups studied and there did not appear to be a change associated with diurnal variation. All individual patients demonstrated less than a threefold fluctuation in HCV RNA throughout the study period. Hence HCV RNA levels remain relatively stable in untreated individuals with chronic HCV infection. Changes of a magnitude of threefold (0.5 log) or greater in HCV RNA levels were not observed in untreated patients.
Replication of hepatitis delta virus
Authors: Monjardino J.
Published: December 2007

SUMMARY. Hepatitis delta virus (HDV) is a unique viroid‐like human pathogen that is always associated with hepatitis B infection. Replication of HDV involves the transcription of genomic RNA, probably by the host RNA polymerase II, by a rolling circle mechanism followed by self‐cleavage and self‐ligation. Editing of antigenomic RNA, possibly involving the enzyme adenosine deaminase, generates two functionally distinct forms of delta antigen. The molecular basis for HDV pathogenicity remains uncertain.
A double blind, placebo‐controlled study to assess the effect of famciclovir on virus replication in patients with chronic hepatitis B virus infection
Authors: Main J. , Brown J. L. , Howells C. , Galassini R. , Crossey M. , Karayiannis P. , Georgiou P. , Atkinson G. , Thomas H. C.
Published: December 2007

SUMMARY. This is the first double‐blind controlled study of famciclovir, an oral antiviral agent, as potential therapy for chronic hepatitis B virus (HBV) carriers. A fall of more than 90% in HBV DNA levels was noted in six of 11 evaluable patients treated with a 10 day course of oral famciclovir. Further studies with more prolonged therapy are ongoing.
Hepatitis G virus RNA in the serum of patients with elevated gamma glutamyl transpeptidase and alkaline phosphatase: a specific liver disease
Authors: Colombatto P. , Randone A. , Civitico G. , Gorin J. Monti , Dolci L. , Medaina N. , Oliveri F. , Verme G. , Marchiaro G. , Pagni R. , Karayiannis P. , Thomas H. C. , Hess G. , Bonino F. , Brunetto M. R.
Published: December 2007

SUMMARY. We tested the sera of 67 consecutive patients for hepatitis G virus (HGV) RNA by reverse transcriptase‐polymerase chain reaction (RT‐PCR). These patients (42 males and 2 5 females, median age 35 years, range 13–64 years) had liver disease of unknown aetiology and were without markers of hepatitis (A‐E) viruses or signs of genetically determined, autoimmune, alcoholic or drug‐induced liver disease. The controls in this study were 110 patients (50 females and 60 males, median age 45 years, range 9–65 years) with chronic hepatitis B virus (HBV) infection (19 patients) or hepatitis C virus (HCV) infection (91 patients). Ten of 67 (14.9%) patients with cryptogenic disease were positive for HGV RNA by at least three separate tests; HGV RNA was also detected in one of 19 (5.3%) hepatitis B surface antigen (HBsAg) carriers and in nine of 91 (16.6%) patients with antibody to HCV. These data suggest that HGV occurs as frequently in HCV infected patients as in those with cryptogenic disease. Elevated serum gamma glutamyl transpeptidase (γ‐GT) (higher than twice the normal value) and alkaline phosphatase levels were found in eight of 10 (80%) HGV RNA positive patients and in six of 57 (10.5%) HGV RNA negative patients (P < 0.0001). Five (50%) HGV RNA positive patients had non‐specific inflammatory bile duct lesions. A statistically significant difference was observed between HGV RNA positive and negative patients with chronic HBV or HCV infections (P < 0.029). Therefore, the spectrum of liver disease associated with HGV is wide, but a characteristic lesion of the bile duct leading to elevation of cholestatic enzymes might be specific for this virus.
Prevalence and disease association of hepatitis G virus infection in Japan
Authors: Nakatsuji Y. , Shih J. Wai‐Kuo , Tanaka E. , Kiyosawa K. , Jr. J. Wages , Kim J. P. , Alter H. J.
Published: December 2007

SUMMARY. A reverse transcriptase‐polymerase chain reaction procedure (RT‐PCR) for the detection of hepatitis G virus (HGV) RNA was used to examine the prevalence of HGV infection and HGV‐related disease in Japan. Among 48 patients with acute non‐A, B, C, D, E (non‐A‐E) hepatitis (five transfusion‐associated cases and 43 sporadic cases), only one patient (2%), a transfusion recipient, was HGV RNA positive. Similarly, among 50 patients with established chronic non‐A‐E hepatitis, only two (4%) were positive for HGV RNA. These frequencies were not significantly different from those in 129 voluntary blood donors (0.8%). By contrast, HGV infection was relatively common among patients who were also infected with other hepatitis viruses. HGV co‐infection or superinfection was found in seven of 53 (13%) patients with acute hepatitis C, in 15 of 126 (12%) patients with chronic hepatitis C, in three of 21 (14%) patients with acute hepatitis B and in four of 81 (5%) patients with chronic hepatitis B. Among the 29 dually infected patients, 15 (52%) had a history of blood transfusion. HGV was also detected in seven (10%) of 69 haemodialysis patients, of whom only one had a dual infection with hepatitis C virus (HCV) and an elevated aminotransferase level. In conclusion: HGV RNA was found in only a low percentage of patients with either acute or chronic non‐A‐E hepatitis; HGV appears to co‐infect or superinfect in 10–15% of HCV infections and in 5–15% of HBV infections; the prevalence of HGV infection (0.8%) among voluntary blood donors in Japan is similar to that for HCV infection; a history of blood transfusion was obtained in 22 (55%) of the total 40 HGV‐positive subjects; and isolated HGV infection appears to have a low disease burden.
Myasthenia gravis and hepatitis C virus infection
Authors: Halfon P. , Levy M. , Marco M. San , Gerolami V. , Khiri H. , Bourliere M. , Feryn J.M. , Gastaut J.L. , Pouget J. , Cartouzou G.
Published: December 2007

SUMMARY. Chronic hepatitis C virus (HCV) infections are often associated with extrahepatic immunological manifestations, including various autoimmune disorders. The aims of this study were to determine the prevalence of HCV markers in patients with myasthenia gravis (MG) and to determine any relationship with HCV infection. Eighty‐three patients with MG, 40 men aged 20–93 years and 43 women aged 13–87 years (mean age 54 years) were studied. The MG patients were positive for antibody to acetylcholine receptor, in addition, their sera was analysed for antibody to HCV (HCVAb) and HCV RNA. HCVAb was detected in two of the 83 patients (2.4%). Four patients were repeatedly HCV RNA positive. They were infected by HCV genotype 1 (one patient), HCV genotype 2a (two patients) and an undetermined HCV genotype in one patient. They received plasmapheresis or intravenous immunoglobulin treatment. Among the four patients, one was infected after the onset of MG without receiving a blood transfusion or using intravenous drugs. The other three had chronic hepatitis C which was discovered at the same time as MG and only one patient had been exposed to blood products. The prevalence of HCV markers in patients with MG (4.8%) was higher than that reported for the general French population, about 1%. This prevalence is similar to that occurring in patients exposed to plasmapheresis or intravenous immunoglobulin. In conclusion, HCV appears to play little, if any, role in causing MG. The higher prevalence of infection among MG patients may be related to transmission in the course of therapy.
Interpretation and use of microbiological findings in dental caries
Authors: Bowen William H.
Published: December 2007

Dental caries results from the interaction of specific bacteria with sugars on a susceptible tooth surface. Although it is generally accepted that caries is an infectious and transmissible disease, expression of the infection is heavily dependent upon frequent ingestion of sugars. The populations of organisms associated with dental caries are influenced by dietary constituents. Therefore the interpretation of results from any laboratory tests should not be done in isolation but should include clinical examination and history. Streptococcus mutans and lactobacilli are the organisms most frequently used to monitor caries activity. There are a wide range of media suitable for growth of the microorganism although none is completely satisfactory. The use of adenylate energy charge and fluorescent antibody techniques might provide more precise results than those currently available. Results from tests may be used to monitor infection levels in young persons, to determine compliance with preventive regimens, identify groups who have high risk of developing caries and in the development of suitable groups for clinical trials.
Characteristics of a hydrogen peroxide‐forming pyruvate oxidase from Streptococcus sanguis
Authors: Carlsson Jan , Edlund May‐Britt K. , Lundmark Siv K. E.
Published: December 2007

A cytoplasmic pyruvate oxidase was partially purified from Streptococcus sanguis ATCC 10556. The enzyme used pyruvate, inorganic phosphate and oxygen as substrates, and formed acetyl phosphate and hydrogen peroxide. In this reaction carbon dioxide can also be expected, but this product was not looked for. The enzyme was dependent on thiamine pyrophosphate (TPP), flavin adenine dinucleotide (FAD) and magnesium ions for activity. Its relative molecular weight (Afr) was 260,000 as calculated from its migration distance in polyacrylamide gradient gel. The enzyme was hysteretic and its activity was not influenced by various low molecular‐weight substances known to be present in the cytoplasm. The pH optimum of the enzyme was 6.7 to 7.5 and its activity was not inhibited by 1 mM hydrogen peroxide or iodoacetamide, or by 10 mM potassium cyanide, sodium azide, iodoacetate, sodium fluoride, zinc chloride, EDTA, or dithiothreitol.
Taxonomic study of spirochetes isolated from human periodontal lesions
Authors: Fukumoto Y. , Okuda K. , Kato T. , Ohta K. , Takazoe I.
Published: December 2007

Nineteen strains of spirochetes obtained from subgingival plaque of 19 patients with advanced periodontitis were studied morphologically, biochemically, and genetically and compared with type strains of Treponema denticola and Treponema socranskii. The results showed that 16 strains which biochemically resembled T. denticola could be divided into two groups based on G + C content and DNA homology. Two isolates appeared to belong to the T. socranskii species. One intermediate size isolate did not fit any known Treponema species.
Effect of dental plaque on the oxidative metabolism of normal neutrophils
Authors: Charon J. A. , Joachim F. , Champagne C. , Torpier G. , Capron A.
Published: December 2007

The purpose of this study was to investigate the interaction between dental plaque and the oxidative metabolism of blood (PB), crevicular (CR) and salivary (SAL) PMN. Data indicated that supragingival plaque induced an in vitro production of chemiluminescence by both PB and CR – PMN in a dose‐dependent manner with a maximum activity after 30 min incubation. Comparison between PB, CR and SAL‐PMNs indicated that 1) both CR and SAL‐PMNs spontaneously produced large quantities of oxygen radicals, 2) CR and SAL‐PMNs further produced oxygen radicals upon phorbol myristate acetate or opsonized‐zymosan stimulation, and 3) SAL‐PMN could not be further activated by supragingival plaque.
Actinobacillus actinomycetemcomitans, Bacteroides gingivalis and Bacteroides intermedius: predictors of attachment loss?
Authors: Wennström Jan L. , Dahlén Gunnar , Svensson Jörgen , Nyman Sture
Published: December 2007

Abstract The purpose of the present prospective study was to evaluate whether Actinobacillus actinomycetemcomitans, Bacteroides gingivalis and Bacteroides intermedius can be used to predict periodontal tissue destruction in sites with clinical signs of inflammation; 44 periodontal pockets in 30 adult patients were selected on the basis of (i) a probing depth of ≥6 mm and (ii) bleeding upon pocket probing. Assessments of oral hygiene and gingival conditions, probing pocket depths, probing attachment levels and bleeding upon probing were carried out at baseline and once every 3 months during a 1‐year period without periodontal treatment. Subgingival bacterial samples were collected from each site at baseline, at the 1‐year examination and at the intervening examinations if a site demonstrated ≥2 mm loss of probing attachment as compared with the baseline value. Following cultivation of the samples the proportions of A. actinomycetemcomitans, B. gingivalis and B. intermedius were determined in relation to the total viable count. The results demonstrated that at sites with an absence of A. actinomycetemcomitans and B. gingivalis or presence of less than 5%B. intermedius, no clinically significant loss of probing attachment (≥2 mm) occurred during the 1‐year observation period. In 25 sites where A. actinomycetemcomitans, B. gingivalis or ≥5%B. intermedius were present, only 5 showed loss of probing attachment of 2 mm or more. Thus, within the limitations of the study, it appeared that the absence of these “indicator” bacteria is a better predictor of no further loss of attachment than the presence of them for disease progression.
Evidence for the existence of two classes of corncob (coaggregation) receptor in Fusobacterium nucleatum
Authors: Kaufman Judy , DiRienzo Joseph M.
Published: December 2007

Oral isolates of Fusobacterium nucleatum have the ability to form distinct coaggregation units, termed corncobs, when mixed with Streptococcus sanguis. Saturation binding kinetics determined for 12 strains of F. nucleatum revealed that these strains could be divided into two groups. One group, represented by F. nucleatum ATCC 10953 reproducibly bound twice as many streptococci as the other group, exemplified by F. nucleatum FDC 364. Other Fusobacterium species tested, including F. mortiferum, Fusobacterium periodonticum, Fusobacterium simiae and Fusobacterium necrophporum, failed to form corncobs with S. sanguis. In inhibition experiments lipoteichoic acid (LTA)‐enriched cell extracts from S. sanguis blocked corncob formation between this bacterium and strain FDC 364 with material containing as little as 50 ng phosphate exhibiting greater than 50% inhibition. Alternatively, 40 times as much material failed to inhibit corncob formation between S. sanguis and F. nucleatum ATCC 10953 or Bacterionema matruchotti. Deacylation of the LTA destroyed its ability to inhibit the fusobacterial coaggregation but produced an active inhibitor in the case of B. matruchotii corncobs. Concerning the fusobacterial coaggregation partner, membrane fractions obtained from strain ATCC 10953 blocked corncob formation while the inhibitory activity of strain FDC 364 was confined to the soluble protein fraction. Corncob‐deficient mutants of F. nucleatum FDC 364 were produced by treating the cells with acridine orange. However, this agent had no effect on the corncob‐forming ability of strain ATCC 10953. The results of these experiments provide convincing evidence that at least 2 independent strain‐specific receptors on F. nucleatum are involved in corncob formation between this bacterium and S. sanguis.
Isolation and characterization of a non‐adherent mutant of Streptococcus sanguis G9B
Authors: Rosan Burton , Eifert Robin , Baker Carol T. , Lamont Richard J.
Published: December 2007

A spontaneous non‐adherent mutant (Adh−) of Streptococcus sanguis, strain G9B has been isolated from a chemostat culture employing a chemically defined medium (FMC) as a nutritional source. The Adh− mutant showed five‐fold less adhesion to saliva‐coated hydroxyapatite (SHA) compared with parent G9B. No difference in adhesion to uncoated hydroxyapatite (HA) was found between G9B and Adh−. The mutant had the same colonial, cellular morphology, and biochemical properties as the parent. A comparison of the antigens found in mutanolysin (M‐1, N‐acetylmuramidase) extracts of G9B and Adh− using crossed rocket immunoelectrophoresis (CIE), indicated that a surface antigen, designated A, reacted strongly in G9B but only weakly in Adh−. The adhesion of G9B but not Adh− to SHA was directly correlated with dilution rates in a chemostat. Adhesion to HA was not affected by the dilution rate. There was also a direct correlation between the concentration of the A antigen with adhesion of G9B to SHA. The concentration of A in Adh− was low at all dilution rates. Antibody to G9B specifically inhibited adhesion of G9B to SHA but antibody to Adh− had no effect on adhesion of either strain to SHA. Neither antibody affected adhesion to HA. A partially purified A antigen absorbed adhesion inhibitory activity of G9B IgG. Trypsin did not digest the A antigen but resulted in the extraction of the antigen from the surface causing the loss of the cells ability to adhere to SHA. Galactose oxidase treated G9B cells also showed a reduced adhesion to SHA but glucose oxidase had no effect. Periodate oxidation of G9B resulted in a loss of adhesion to SHA. The A antigen was found in purified cell walls and was labelled with 125I, indicating a surface location. The A antigen also reacted with affinity purified antibody against the G9B adhesin antigen. Immunoblots of the A antigen following SDS‐PAGE indicated it contained 80, 62, and 52 kDa polypeptides. These results suggest that the A antigen is a glycoprotein which is the native form of the adhesin responsible for the attachment of G9B to salivary pellicle.
Reliability of sensitivity testing of primary culture of acute dentoalveolar abscess
Authors: Lewis Michael A. O. , MacFarlane T. Wallace , McGowan David A.
Published: December 2007

The antibiotic susceptibility of 50 acute dentoalveolar abscesses was determined by testing of primary cultures of pus and secondary cultures of individual isolates, using a comparative disc method. The sensitivity report obtained by primary testing agreed with that of secondary tests for 47 (94%) of the abscesses studied. It is concluded that primary testing of pus samples aspirated from acute dentoalveolar abscess is reliable and can provide the clinician with antibiotic sensitivity results more rapidly than conventional secondary testing, especially when slow‐growing anaerobes are involved.
Production and characterization of monoclonal antibodies specific for Bacteroides gingivalis
Authors: Gmür Rudolf , Werner‐Felmayer Gabriele , Guggenheim Bernhard
Published: December 2007

With the aim of producing specific serological reagents for a direct quantitative evaluation of clinical plaque samples, 12 hybrid cell lines secreting monoclonal antibodies specific for Bacteroides gingivalis, were raised. The specificity of the antibodies was established by enzyme‐linked immunosorbent assays and by indirect immunofluorescence tests involving a panel of 65 strains from 32 species, most of which have an oral habitat. When analysed for different reactivity patterns with various B. gingivalis strains the monoclonal antibodies were found to recognize 2 principal serogroups, which may have the same respective strain composition as previously detected virulence and serogroups. All recognized antigens were found to be expressed on the surface of the bacteria. Immunoblotting tests and analyses of the sensitivity of the recognized epitopes to various denaturing treatments suggested that 3 of 4 monoclonal antibodies reactive with all B. gingivalis strains tested, were directed to lipopolysaccharide epitopes. In contrast, the epitopes with a restricted expression on strains W83 and W50 (serogroup B) appeared to consist of outer membrane carbohydrate moieties.
Selective induction of prostaglandin E production in C3H/HeJ mouse macrophages by lipopolysaccharides from Bacteroides gingivalis
Authors: Hamada S. , Okahashi N. , Fujiwara T. , Nishihara T. , Koga T.
Published: December 2007

Lipopolysaccharides (LPS) were isolated from Bacteroides gingivalis, Escherichia coli, Actinobacillus actinomycetemcomitans, Fusobacterium nucleatum and F. necrophorum by the phenol‐water procedure. These LPS preparations enhanced the production of prostaglandin E by macrophages from BALB/c and C3H/HeN mice. Only B. gingivalis LPS, however, markedly stimulated the production of prostaglandin E by macrophages from “LPS‐nonresponsive” C3H/HeJ mice.
Isolation and characterization of plasmid DMA from Bacteroides strains isolated from the human oral cavity
Authors: Sako Keiji , Takazoe Ichiro , Okuda Katsuji
Published: December 2007

A total of 134 Bacteroides strains isolated from the human oral cavity were examined for plasmid content. Plasmid DNA was isolated from 7 strains of black‐pigmented Bacteroides, including Bacteroides levii strains ATCC 29147 and JP2. All isolated Bacteroides plasmid DNA had a molecular mass of 5.9 M daltons and showed the same electrophoretic pattern when treated with restriction endonuclease. No positive correlation was found between plasmid DNA content and antibiotic resistance, bacteroiocinogenic activity or hemagglutinating activity.
Achromopeptidase for rapid lysis of oral anaerobic Gram‐positive rods.
Authors: Barsotti O. , Morrier J.J. , Freney J. , Renaud F. , Benay G. , Decoret D. , Dumont J.
Published: December 2007

A rapid and simple method for lysing anerobic Gram‐positive rods is described. It is based on the simultaneous action of lysozyme and achromopeptidase (each at 5 mg/g wet weight of cells), followed by the action of SDS (0.2%). The efficiency of the bacterial lysis is measured by the yield of DNA obtained with Marmur's modified procedure. This method permits effective lysis of small amounts of anaerobic rods (200 mg wet weight) independent of their growth phase, and extraction of DNA for further analysis. It is particularly useful for strains with low growth such as certain species of Actinomyces and Bifidobacterium and it saves considerable time.
Degradation of basement membrane collagen by proteases from some anaerobic oral microorganisms
Authors: Uitto V.‐J. , Haapasalo M. , Laakso T. , Salo T.
Published: December 2007

Subepithelial basement membrane (BM) of gingiva serves as an important barrier for bacterial penetration. Degradation of Type IV collagen, a major component of BM, was studied by incubating different Type IV collagen preparations with extracts of cultured oral microorganisms at neutral pH. Of the tested species Bacteroides gingivalis and Treponema denticola showed the strongest capacity to degrade Type IV collagen. Both soluble and insoluble substrates were extensively degraded. Limited cleavage of soluble Type IV collagen was observed by Bacteroides asaccharolyticus, Bacteroides endondontalis and Capnocytophaga ochracea. Negligible activity was found with Bacteroides intermedius, Actinobacillus actinomycetemcomitans and Fusobacterium nucleatum. The general proteolytic activity as assayed by the degradation of fibronectin, elastin, casein and some synthetic aminoacid substrates followed the same trend. B. gingivalis and T. denticola showed the highest proteolytic activity. The others tested showed variable and usually less activity towards the various substrates. According to the results B. gingivalis and T. denticola possess a strong proteolytic arsenal, a characteristic probably related to their virulence.
Ultrastructure of the cell envelope of Bacteroides forsythus strain ATCC 430377T
Authors: Kerosuo Eero
Published: December 2007

The Ultrastructure of the cell envelope of Bacteroides forsythus strain ATCC 43037T was studied by electron microscopy. The thin‐sectioned cells had a surface layer (S‐layer) consisting of serrated subunits (appr. 10 nm) outside the outer membrane. The bulk of the negatively stained, freeze‐etched and metal‐shadowed specimens showed an orthogonal lattice. However, lines parallel to the long axis of the cell were aacentuated, suggesting an oblique symmetry, though occasional fragments of the S‐layer showed a typical tetragonal pattern. Preliminary image processing studies could not exclude either type of symmetry. The presence of periodically arranged inner cell envelope structures reported earlier could not be confirmed.
In vitro susceptibility of Candida species to lysozyme
Authors: Tobgi R S , Samaranayake L P , MacFarlane T W
Published: December 2007

The in vitro sensitivity of 68 oral and vaginal isolates of Candida species to lysozyme was determined by a growth inhibition assay. Experiments with a single isolate of Candida albicans indicated that sensitivity to lysozyme increases in a concentration‐ and time‐dependent manner. The examined Candida species were susceptible to lysozyme in the following decreasing order: Candida krusei (most susceptible), Candida parapsilosis, Candida tropicalis, Candida guilliermondii, Candida albicans and Candida glabrata. However, there were differences in susceptibility to lysozyme among different isolates within a given species. These results indicate that lysozyme may regulate, in a qualitative and quantitative manner, the yeast populations on human mucosal surfaces.
Differentiation between Bacteroides gingivalis, Bacteroides endodontalis and Bacteroides asaccharolyticus by means of HPLC analysis of non‐derivatized free metabolic acids
Authors: Johansen Hege , Olsen Ingar , Kerekes Kasmer
Published: December 2007

A simple, sensitive and accurate method, based on HPLC analysis of non‐derivatized, short‐chain free metabolic acids extracted from a 48‐h PYG culture, has been used for differentiation between the closely related organisms Bacteroides gingivalis, Bacteroides endodontalis and Bacteroides asaccharolyticus. B. gingivalis and B. endodontalis were found to produce acidic end products not previously reported, i.e., parahydroxyphenylacetic acid (B. gingivalis) and an unknown acid, probably aromatic, with retention time 46.49 min (B. endodontalis). B. asaccharolyticus did not generate any of these acids which could be used as chemotaxonomic markers. All species produced pyruvic, succinic, fumaric, formic, acetic, propionic, isobutyric, butyric, isovaleric, and an unknown short‐chain carboxylic acid. HPLC, having several advantages over GLC, deserves more application as an analytical tool in bacterial systematics.
Effect of a bacteriocin‐producing strain of Streptococcus sobrinus on infection and establishment of Streptococcus mutans on tooth surfaces in rats
Authors: Kitamura Kyoichi , Masuda Norio , Kato Kazuo , Sobue Shizuo , Hamada Shigeyuki
Published: December 2007

The effect of bacteriocin produced by Streptococcus sobrinus MT6223 on infection and establishment of Streptococcus mutans MT6222 was studied in specific pathogen‐free rats. These strains were isolated from a carious lesion of a single subject. S. mutans MT6222 was found to be susceptible to the growth inhibitory action of S. sobrinus MT6223. When simultaneously inoculated into the oral cavity of rats, even a small inoculum (105 CFU) of S. sobrinus MT6223 completely inhibited colonization of S. mutans MT6222 on the tooth surface. Also, S. sobrinus MT6223 eliminated S. mutans MT6222 when MT6223 (108 CFU) was inoculated 2 days after the inoculation of 108 CFU cells of MT6222. Similar results were obtained in dental plaque samples from the tooth surface and the fissures of the upper molars at the end of the experiment. However, when S. sobrinus MT6223 108 CFU) was inoculated 2 weeks after the inoculation of S. mutans MT6222 (108 CFU), MT6223 coexisted with MT6222. However, the plaque samples showed that MT6223 inhibited the establishment of MT6222 on smooth surfaces, but not in fissures. In addition, MT6223 protected against subsequent infection with Mr6222. However, a nonbacteriocinogenic mutant of S. sobrinus MT6223 did not inhibit the infection and establishment of S. mutans MT6222.
The effect of subminimal inhibitory concentrations of antimicrobial agents on three bacterial mixtures
Authors: Lacroix Jean‐Michel , Mayrand Denis
Published: December 2007

A test tube technique was developed to screen bacterial mixtures to detect inter‐bacterial interactions that play a role in determining sensitivity to antimicrobial agents. We found 3 mixtures where these bacterial interactions change the sensitivity to antimicrobials or change the proportions of each bacterial species in the mixture. The mixtures were: Fusobacterium nucleatum 102.3 and Bacteroides endodontalis ATCC 35406; F. nucleatum 102.3 and B. endodontalis BN11 a–f; and Capnocytophaga ochracea 1956c and Eubacterium saburreum 162.4. The antimicrobials used were metronidazole for the first 2 mixtures and tetracycline for the last. F. nucleatum seems to protect B. endodontalis from the action of metronidazole. Conversely, the growth inhibition of C. ochracea by E. sahurreum was lifted when tetracycline was present. We also found that the growth of C. ochracea can then permit the subsequent growth of E. saburreum. The test tube method permits the evaluation both of interbacterial interactions and the detection of any protective mechanism against antimicrobial agents in a bacterial mixture. We found that F. nucleatum 102.3 can decrease the metronidazole level in the culture medium, and by the use of 14C‐metronidazole we demonstrated that acetamide is produced from metronidazole.
“Reverse” DMA hybridization method for the rapid identification of subgingival microorganisms
Authors: Smith G. L. F. , Socransky S. S. , Sansone C.
Published: December 2007

A “reverse” hybridization method is described, in which whole chromosomal DNA was extracted from 10‐20 colonies of “unknown” strains in pure culture and labelled with digoxigenin by a random primer technique. DNA probes were prepared from a total of 23 strains and hybridized with targets containing 100 ng purified, denatured DNA from 38 reference strains fixed to nitrocellulose. 21/23 digoxigenin‐labelled DNA probes successfully detected all members of the homologous species present on filters. Probes to Fusobacterium nucleatum strains 364 and MG detected 3/4 and 1/4 members of this species, respectively; 13/23 probes were 100% specific, but cross reactions between 10 probes and DNA targets from closely related, heterologous species occurred in 15/834 possible instances. False‐positive reactions that occurred between closely related species were, however, easily distinguished and did not prevent the accurate identification of probe strains. Digoxigenin‐labelled probes were capable of detecting 100 pg of homologous DNA. The reverse hybridization procedure allows identification or grouping of a large number of isolates within 3 days and provides a more economical means of characterizing subgingival isolates than predominant cultivable techniques and conventional phenotypic testing. This method could be adapted for the direct identification of microorganisms in subgingival plaque samples
Mutans streptococci and lactobacilli in saliva from children with insulin‐dependent diabetes mellitus
Authors: Twetman Svante , Aronsson Stefan , Björkman Stein
Published: December 2007

The quantitative distribution of mutans streptococci and lactobacilli in saliva of insulin‐dependent diabettic children was compared witha group of healthy children and related to the metabolic control of the disease. The study group, consisting of 94 boys and girls (age 4‐19) with type 1 diabetes was matched by sex and age witha non‐diabetic control group. Stimulated whole saliva was collected and flow rate, buffer capacity and the levels of mutans streptococci and lactobacilli were analysed in all children. In the diabetic group, total salivary proteins and glucose content of saliva were determined. Data on caries experience were recorded from the dental cards of all children. There were no difference in the distribution or number of mutans streptococci between the groups, but significantly (p < 0.05) lower levels of lactobacilli were found among the diabetic children. The number of lactobacilli was positively correlated (p < 0.05) to glucose concentration in saliva. There was no difference in the prevalence of caries between the groups. The present findings suggest that the dietary treatment of young insulin dependent diabetics gives rise to a reduced number of lactobacilli in saliva but does not affect the mutans streptococci.
Studies on the virulence properties and metabolism of pleiotropic mutants of Porphyromonas gingivalis (Bacteroides gingivalis) W50
Authors: Shah H. N. , Seddon S. V. , Gharbia S. E.
Published: December 2007

Porphyromonas gingivalis (Bacteorides gingivalis) strain W50 and variants isolated from continuous culture designated W50/BP1 (black pigmented), W50/BR1 (brown pigmented) and W50/BE1 (beige or non‐pigmented) were previously shown to lose virulence with the loss of pigmentation (8). Major properties which may affect the virulence and metabolism of P. gingivalis were compared amongst the 4 strains. The non‐pigmented strain lost the ability to hemagglutinate sheep erythrocyte, had a reduced hydrophobicity and possessed lower levels of proteolytic activity. Defects in the electron transport system occurred at the level of cytochrome b but not menaquinone synthesis and resulted in an altered metabolic end product profile of the non‐pigmented strain.
In vivo chemotaxis evoked by Actinobacillus actinomycetemcomitans and Haemophilus aphrophilus
Authors: Holm Anders , Kalfas Sotirios , Holm Stig E.
Published: December 2007

The chemotaxis‐evoking capacity of 5 Actinobacillus actinomycetemcomitans and 5 Haemophilus aphrophilus strains were studied in a tissue cage model in rabbits. A significant increase of the total number of polymorphonuclear leukocytes was induced in the tissue cage fluid by both viable and killed bacteria, reaching a maximum after 12–24 h. In parallel, the proportion of viable/non viable leukocytes increased. The leukocyte counts declined during the following 24–48 h in all chambers except in those inoculated with viable cells of H. aphrophilus. The H. aphrophilus strains survived the 72 h experiment while A. actinomycetemcomitans decreased to undetectable levels within 24–72 h. Lactate dehydrogenase and lysozyme activities in cage fluid increased in all but the un inoculated chambers. Viable bacteria induced higher activities of the enzymes than killed ones. It is concluded that both species of bacteria exhibit similar chemotaxis evoking properties. A strain dependent ability to induce release of leukocyte‐associated enzymes exists.
Rapid method for the purification of DNA from subgingival microorganisms
Authors: Smith G. L. F. , Socransky S. S. , Smith C. M.
Published: December 2007

A method is described which facilitates the rapid purification of high molecular weight chromosomal DNA from gram positive and gram negative bacteria grown on solid media. A total of 32 reference strains and fresh isolates were examined in this study. The purification procedure involved lysis of cells with SDS in the presence of proteinase K, followed by removal of cellular polysaccharides and proteins with hexadecyltrimethyl ammonium bromide (CTAB) and phenol:chloroform:isoamyl alcohol. Preparations were incubated with RNase and, after removal of the enzyme, DNA was precipitated with ethanol. Several hundred micrograms of DNA could be prepared within 5 h from cells grown on 1–2 agar plates. None of the final preparations contained RNA; protein was detected in 12/32 preparations. The resultant DNA proved suitable for restriction enzyme digestion and biotin‐labelling by a random primer technique. DNA probes constructed from these preparations were capable of detecting 100 pg of homologous target DNA fixed to nitrocellulose. Cross reactions between closely related species displayed weaker signal intensities than, and, thus, were easily distinguished from, true positive reactions between homologous species. DNA obtained by this procedure may also be suitable for DNA‐DNA homology studies, recombinant DNA experiments and molecular fingerprinting.
Actinobacillus actinomycetemcomitans mitogenicity for B cells can be attributed to lipopolysaccharide
Authors: Eastcott Jean W. , Taubman Martin A. , Smith Daniel J. , Holt Stanley C.
Published: December 2007

The purpose of this investigation was to determine the component(s) of whole Actinobacillus actinomycetemcomitans bacteria responsible for B cell mitogenic activity. Congenitally athymic “nude” rats were used as a source of B cells devoid of T lymphocyte activity. Spleen cells were cultured with, or without, whole formalin‐killed A. actinomycetemcomitans bacteria or with purified LPS from A. actinomycetemcomitans. Dose‐response curves to A. actinomycetemcomitans cells or to A. actinomycetemcomitans‐LPS showed that responses were dose dependent. If optimal quantities of both A. actinomycetemcomitans and A. actinomycetemcomitans‐LPS were added in combination, the proliferative responses were the same as if either was added alone, i.e., the responses were not additive. Polymyxin B at 2μg/well completely abrogated the proliferative response of athymic rat splenocytes to 107A. actinomycetemcomitans cells or to 1.25 μg A. actinomycetemcomitans‐LPS/well. Therefore, the in vitro early proliferative response of B cells to A. actinomycetemcomitans can be attributed to the presence of LPS on A. actinomycetemcomitans cells. A considerable portion of the in situ lymphocytic gingival response to A. actinomycetemcomitans infection seen in periodontal disease patients may be a B cell mitogenic response to the LPS of this bacterium.
Sorbitol‐fermenting predominant cultivable flora of human dental plaque in relation to sorbitol adaptation and salivary secretion rate
Authors: Kalfas Sotirios , Edwardsson Stig
Published: December 2007

The sorbitol‐fermenting predominant flora of human dental plaque was studied in 12 people with low and 11 with normal salivary secretion rates before and after a period of frequent mouth rinses with sorbitol solution. A total of 277 sorbitol‐fermenting isolates are described by their morphological and physiological characteristics. The flora was almost exclusively composed of gram‐positive bacteria belonging to the genera Streptococcus, Lactobacillus and Actinomyces in people with low secretion rates and Streptococcus and Actinomyces in those with normal salivation. At the species level, Streptococcus mutans predominated in all. The frequent use of sorbitol resulted in an increase of the streptococcal species mainly and particularly of Streptococcus sanguis I in people with normal salivation. The counts of lactobacilli and Actinomyces remained unaffected. Almost all isolates appeared to belong to the resident plaque flora. Succession of new sorbitol‐fermenting genera to the plaque community could not be observed as a result of the frequent exposure of the mouth to sorbitol.
Salivary IgA antibody to oral streptococcal antigens in predentate infants
Authors: Smith Daniel J. , King William F. , Taubman Martin A.
Published: December 2007

Salivary IgA antibodies to oral streptococci which colonize the infant oral cavity soon after birth were analyzed in 53 whole salivas of 17 infants who were between three and 27 weeks old. Antibody activities to Streptococcus mitis cells were detected by enzyme linked immunosorbant assay in 78% of the whole salivas by the twelfth week of age. This antibody activity was associated with polymeric IgA as determined after gel filtration of salivas on Superose 6, followed by ELISA. Western blot analyses were used to detect IgA antibodies to Streptococcus mitis and Streptococcus salivarius culture supernatants. Forty one, and 91% of saliva samples contained IgA antibody which reacted in Western blot analyses with S. salivarius and S. mitis culture supernatants, respectively. The youngest infant to show reactive IgA antibody with either oral streptococcal antigen preparation was five weeks old. Salivary IgA antibody to either bacterial culture supernatant was detected in Western blot only after the isolation of the respective streptococcal species from the oral cavity of these young infants. Some heterogeneity was observed among patterns developed with salivas from different infants. These results suggest that salivary IgA antibody responses may be induced by oral colonization (S. mitis, S. salivarius) by the end of the first month of life.