bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of two second‐generation anti‐hepatitis C virus ELISA on 21431 US blood donor samples
Authors: Anderson S. C. , Hathaway T. , Kuramoto I. K. , Holland P. V. , Gilchec R. , Koch T. , Hojvat S.
Published: December 2007

SUMMARY. We have compared two different second‐generation (2.O) enzyme‐linked immunosorbent assays (ELISA) for the presence of antibodies to hepatitis C virus (anti‐HCV) in blood from volunteer, unpaid donors. At two separate blood centres, a total of 21431 donor samples were tested with Abbott Anti‐HCV 2.0 ELISA and Ortho Anti‐HCV 2.0 ELISA. Samples found to be repeatedly reactive were tested by supple‐mental/investigational assays, MATRIX HCV (Abbott) and anti‐HCV RIBA II (Ortho/Chiron), to ‘confirm’ the presence of anti‐HCV. Discordant ELISA samples were additionally tested by the polymerase chain reaction (PCR) for the presence of HCV RNA. The Abbott anti‐HCV assay had a repeatedly reactive rate of 0.59% (127/21431) and the Ortho anti‐HCV assay 0.51% (110/21431). Overall agreement between assays was 99.76%. 72/127 (56.7%) of Abbott repeatedly reactive samples confirmed on MATRIX and 61/127 (48.0%) on RIBAII; 70/110 (63.6%) of Ortho repeatedly reactivate samples confirmed on MATRIX and 61/110 (55.5%) on RIBA II. Discordant ELISA samples tested by PCR yielded negative results. Hence the two ELISA had equal sensitivity, as defined by detection of true positive samples: the slightly lower specificity of the Abbott Anti‐HCV 2.0 ELISA may be owing to culling of donors with a false positive test by Ortho's Anti‐HCV 1.0 and 2.0 ELISA tests (the routine tests in place at each blood centre). A sample found to be repeatedly reactive by two different ELISA tests for anti‐HCV is likely to be a true positive and may not require further ‘confirmatory’ testing.
Hepatitis B virus transcriptional activators: mechanisms and possible role in oncogenesis
Authors: Henkler F. , Koshy R.
Published: December 2007

Summary The hepatitis B virus (HBV) genome encodes a 154 amino acid protein termed X (HBx, hepatitis Bx protein), which is a promiscuous transcriptional activator of polymerase II and III promoters. HBx upregulates a wide range of cellular and viral genes and is thought to facilitate viral pregenome and mRNA transcription; however, its precise role in the viral replication cycle remains to be elucidated. The functional mechanisms of HBx appear very complex. It was shown to activate transcription factors AP‐1 and NF‐kB via cytoplasmic signalling pathways including ras‐MAP kinase. In contrast, nuclear HBx is thought to activate the transcriptional machinery directly. A second transcriptional activator protein (Mst, middle s transactivator) is encoded by 3′‐truncated preS2/S sequences of integrated HBV DNA, but not by the intact viral gene. HBx and Mst may contribute to the pathogenicity of chronic hepatitis B and are suggested to promote hepatocyte transformation via upregulation of cellular proto‐oncogenes. Further, HBx may enhance HBV related carcinogenesis by inactivation of the tumour suppressor gene product p53.
Long‐term interferon‐α treatment of children with chronic hepatitis delta: a multicentre study
Authors: Marco V. Di , Giacchino R. , Timitilli A. , Bortolotti F. , Crivellaro C. , Calzia R. , Iannuzzi C. , Prestileo T. , Vajro P. , Nebbia G. , Stringhi C. , Rosina F. , Biassoni D. , Callea F. , Rizzetto M. , Craxi A.
Published: December 2007

Summary We assessed the efficacy of prolonged interferon‐α (IFN) therapy in children with chronic hepatitis caused by hepatitis delta virus (HDV) by treating 26 paediatric cases with IFN‐α2b(5 MU m‐2, then 3 MU m‐2 three times weekly for 12 (medium‐term group, MTG) or 24 months (long‐term group, LTG). Compliance and tolerability were acceptable. At the end of therapy a complete biochemical response [normalization of alanine aminotransferase (ALT)] occurred in 12 children (5/13 in MTG and 7/13 in LTG). A relapse occurred after stopping IFN in 10 cases (five in MTG and five in LTG). Two patients from the LTG had normal liver function tests during 12 months of follow‐up. Six of the eight hepatitis Be antigen (HBeAg) positive children lost HBeAg, while all six hepatitis B virus (HBV) DNA positive patients lost HBV DNA during treatment. HBeAg reappeared later in two children. HDV RNA, present in 10/10 cases of MTG before treatment, persisted after 12 months IFN therapy in 3/10. One year after stopping therapy, 8/10 patients were again HDV RNA positive. Two children cleared hepatitis delta antigen (HDVAg) from the liver. No significant improvements in liver histology were seen in both groups. Our experience suggests that IFN‐α treatment in children with chronic type D hepatitis has a transient effect, and long‐term treatment does not appear to induce a greater therapeutic benefit in terms of biochemical and virological response.
Relationship between the serum alanine aminotransferase level at the end of interferon treatment and histologic changes in wild‐type and precore mutant hepatitis B virus infections
Authors: Bayraktar Y. , Koseoglu T. , Temizer A. , Kayhan B. , Thiel D. H. Van , Uzunalimoglu B.
Published: December 2007

Summary Unravelling the role of interferon (IFN) in the treatment of chronic hepatitis B is complicated by many factors. Several mutant forms of hepatitis B virus (HBV) have recently been discovered; the most common of these is the precore mutant, characterized by hepatitis Be antigen (HBeAg) negativity and hepatitis Be antibody (HBeAb) positivity in an individual with an active HBV infection. The aim of this study was to compare the response rate to IFN therapy in patients with wild‐type HBV infection and in individuals infected with the precore mutant. A second aim was to evaluate the role of an increased serum ferritin in terms of the IFN response rate in these two different types of HBV infection.

Therapy ministered at a dose of 5 MU subcutaneously three times weekly for 6 months to 41 individuals with a chronic wild‐type hepatitis B infection and 16 individuals with a precore mutant chronic HBV infection. An IFN response was defined as normalization of the serum alanine aminotransferase (ALT) level and an HBeAg to HBeAb seroconversion (in wild‐type hepatitis infection), and a normalization of the serum ALT in individuals infected with a precore mutant infection.

Ntrywo groups were matched for age, gender, serum ALT, serum iron, total iron binding capacity (TIBC), serum ferritin and liver histology. Forty‐six per cent of the subjects with wild‐type disease responded to IFN therapy. By contrast, only four of the 16 cases (25%) of the precore mutant cases responded (P < 0.05). Ferritin levels correlated well with the type of IFN response; as the serum ferritin level increased, the response rate to IFN declined. Hapatic infection caused by a precore HBV mutant is more resistant to IFN therapy than wild‐type infection. The serum ferritin level appears to influence the type of IFN response achieved. Individuals with a serum ferritin level greater than 300 ng ml‐1 failed to respond to IFN in 93% of the cases studied.
The effect of granulocyte—macrophage colony‐stimulating factor (GM‐CSF) on hepatitis B vaccination in haemodialysis patients
Authors: Hess G. , Kreiter F. , Kösters W. , Deusch K.
Published: December 2007

Summary Haemodialysis patients often fail to respond to hepatitis B vaccination. In this pilot study, 15 patients previously non‐responsive to at least three 40 μg doses of hepatitis B vaccine were given 0.5, 5 or 10μg kg‐1 granulocyte‐macrophage colony‐stimulating factor (GM‐CSF) subcutaneously 24 h prior to booster vaccination with a hepatitis B vaccine. Seven of the 15 patients developed antibody to hepatitis B surface antigen (HBsAb) (35–7240 IU L‐1) upon initial vaccination with GM‐CSF and two of four individuals responded with low HBsAb titres of 15 and 60 IU L‐1 when revaccinated with hepatitis B surface antigen (HBsAg) and twice the dose of GM‐CSF. The application of GM‐CSF was associated with adverse effects that were, in general, mild to moderate in severity and appeared to be dose dependent. Two patients, both receiving 10 μg kg‐1 GM‐CSF discontinued the study because of severe hypotension.
Hepatitis C virus RNA quantification in right and left lobes of the liver in patients with chronic hepatitis C
Authors: Idrovo V. , Dailey P. J. , Jeffers L. J. , Coelho‐Little E. , Bernstein D. , Bartholomew M. , Alvarez L. , Urdea M. S. , Collins M. L. , Schiff E. R.
Published: December 2007

Summary. Quantification of hepatitis C virus RNA in liver tissue is likely to be useful in the study of the natural history, pathogenesis, progression and treatment of hepatitis C virus‐associated liver disease. Quantitative measurements of hepatitis C virus RNA in liver biopsy samples using the branched DNA (bDNA) signal amplification assay were carried out. The aims of this study were threefold: first, to assess the level of hepatitis C virus RNA in biopsy samples from the right and left lobes of the liver; second, to evaluate the correlation between hepatitis C virus RNA levels in serum and liver; and third, to investigate the relationship between serum and liver hepatitis C virus RNA levels and the severity of hepatic histology in non‐cirrhotic patients with chronic hepatitis C. There was a strong correlation (r= 0.92, P < 0.01) between hepatitis C virus RNA levels in the right and left lobes of the liver as well as a strong correlation between hepatitis C virus RNA levels in liver and serum (r= 0.82, P < 0.01). However, there was no significant correlation between the severity of hepatic histology and levels of hepatitis C virus RNA in serum and liver among patients with chronic active hepatitis classified according to Knodell's hepatic activity index (KI). Our results indicate that hepatitis C virus RNA quantification from a single liver biopsy is representative of both lobes in patients with chronic hepatitis, and suggest that serum hepatitis C virus RNA levels are a meaningful reflection of hepatitis C virus RNA levels in the liver.
Response to interferon‐α of Egyptian patients infected with hepatitis C virus genotype 4
Authors: El‐Zayadi A. , Simmonds P. , Dabbous H. , Prescott L. , Selim O. , Andy A.
Published: December 2007

Summary. Hepatitis C virus (HCV) genotype 4 is the principal HCV genotype found in Egypt and the Middle East. Little is known concerning its propensity to cause disease and the frequency with which infected individuals respond to interferon‐α (IFN‐α). We have investigated the response to treatment in a cohort of 100 chronic hepatitis C patients infected with genotype 4. All patients had biopsy‐proven chronic active liver disease. Each was treated with 3 million units (MU) IFN‐α, thrice weekly. Response was monitored, in 92 patients who completed treatment, by alanine aminotransferase (ALT) measurements and by polymerase chain reaction (PCR) for HCV. ALT levels remained abnormal in 64 patients during treatment (69.6%). Of the 28 patients who showed a biochemical response during treatment (30.4%), 18 maintained this over the 6‐month post‐treatment period. Amongst the sustained biochemical responders, HCV RNA was cleared from serum in only four of the 18 (22.2%) in this period. Histological improvement was observed in 26/51 (50.9%) of the patients who had a second biopsy.

Hence, patients infected with HCV genotype 4 show a poor response to IFN‐α therapy compared with genotypes 2 and 3, but a similar response to IFN‐α compared with those infected with type 1b HCV. These findings have major implications for treatment strategies in the Middle East, including Egypt, where HCV genotype 4 is widely distributed.
Detectable levels of IgM antibodies to hepatitis C virus core protein predict breakthrough in patients with chronic hepatitis C treated with interferon‐α
Authors: Fracassetti O. , Tambini R. , Perani V. , Vicari O. , Lorenzi N. , Delvecchio G.
Published: December 2007

Summary. The predictive value of IgM antibodies to hepatitis C virus core antigen (HCcAb) is controversial. We studied 79 patients undergoing interferon‐α (IFN‐α) treatment and we found that detectable levels of IgM HCcAb could predict breakthrough on treatment.
Replication of hepatitis C virus
Authors: Yoshikura H. , Hijikata M. , Nakajima N. , Shimizu Y. K.
Published: December 2007

SUMMARY. The mode of replication of the hepatitis C virus (HCV) remains poorly understood. Attempts to produce a tissue culture model containing replicating HCV have been largely unsuccessful. Recent studies on sera from patients chronically infected with HCV have shown that viral particles may be found in high‐or low‐density fractions. High‐density fractions contain non‐infectious virions whilst infectious particles can be derived from low‐density material. Using appropriate infectious fractions we have successfully infected a number of human cell lines allowing studies of HCV replication to be initiated.
Visualization of hepatitis C virions and putative defective interfering particles isolated from low‐density lipoproteins
Authors: Prince A. M. , Huima‐Byron T. , Parker T. S. , Levine D. M.
Published: December 2007

SUMMARY. Hepatitis C virus (HCV) in highly infectious sera has been shown to be predominantly associated with low‐density lipoproteins. To determine whether the association is specific to low‐density lipoproteins (LDL) or very low‐density lipoproteins (VLDL), we fractionated HCV‐containing plasma by a column chromatographic procedure known to separate these classes. Hepatitis C virus RNA detected by polymerase chain reaction (PCR) was associated primarily with the very low‐density (VLDL) fraction. However, it could not be ruled out that virus‐associated LDL may have eluted with this fraction. Hepatitis C virus virions isolated from sera having sufficient titre for visualization by electron microscopy are generally coated with antiviral antibodies, therefore we utilized the lipid association to isolate antibody‐free virions. Very low‐density lipoproteins were isolated by ultracentrifugal flotation and then treated with deoxycholate to release the virions. These were then isolated in a highly purified form by centrifugation in a sucrose gradient. The 1.10–1.11 gml‐1 region of the gradients contained 60–70 nm particles. Particles with similar surface structure but having a diameter of only 30–40 nm constituted about 30% of the total. The latter may represent defective interfering particles. The identity of both small and large particles with HCV virions and associated particles was confirmed by their trapping on grids by an anti‐HCV E2 monoclonal antibody, and by their aggregation by rabbit antiserum to an amino‐terminal peptide of E1. Thus, both E1 and E2 epitopes are displayed on the surface of intact HCV virions.
Virus and host factors are both important determinants of response to interferon treatment among patients with chronic hepatitis C
Authors: Lin R. , Liddle C. , Byth K. , Farrell G. C.
Published: December 2007

SUMMARY. Virus and host factors have both been linked to the response to interferon treatment among patients with chronic hepatitis C but their relative importance and potential interactions are unclear. Hepatitis C virus genotype and level of viraemia were determined in pretreatment sera from 65 Australian patients treated with interferon‐α2b (IFN‐α2b). 3 MU tiw for 6 months. Hepatitis C viraemia was quantitated by a competitive reverse transcription‐polymerase chain reaction (RT‐PCR) method and genotype was determined by a line probe assay. By univariate analysis, there were positive associations between initial (short‐term) responses to IFN treatment and younger age (P= 0.004). absence of cirrhosis (P= 0.01). and injecting drug use as risk factor for infection (P= 0.05) but not gender, duration of infection, or level of viraemia. Genotype appeared to be important (P= 0.06) but failed to reach statistical significance. By multivariate analysis, absence of cirrhosis was the only significant independent predictor of treatment response (P= 0.01). Among initial responders, the factors associated with long‐term response were the pretreatment HCV RNA titre and the duration of infection. There was a close association between viral genotype, but not viral load, and the severity of liver disease. An interplay of factors determines the outcome of a 6‐month course of interferon treatment for hepatitis C. Severity of liver disease, but not the viral load, is the most crucial determinant of initial response to interferon, and histological severity appeared to be influenced by the viral genotype. The level of hepatitis C virus (HCV) viraemia and the duration of infection are independent determinants of long‐term response by affecting the relapse rate after interferon treatment.
Risk of hepatitis C virus infection among household contacts of Saudi patients with chronic liver disease
Authors: Arif M. , Al‐Swayeh M. , Al‐Faleh F. Z. , Ramia S.
Published: December 2007

SUMMARY. To evaluate the intrafamilial transmission of heptitis C virus and related risk factors among the Saudi population, two groups were investigated: 120 index patients with chronic liver disease and their 127 family contacts, and 220 blood donors who were anti‐HCV‐positive but with no chronic liver disease and their 91 family contacts. After a questionnaire on the risk factors for parenteral exposure, blood samples were obtained and tested for liver biochemistry and antibody to HCV (anti‐HCV) by a third‐generation enzyme immunoassay (UBI HCV HA4.0). Only two spouses of 20 index patients were anti‐HCV‐positive while the remaining 125 family contacts were anti‐HCV‐negative. None of the 91 family contacts of the 20 anti‐HCV‐positive blood donors was anti‐HCV‐positive. The two spouses were wives of index patients but had a history of blood transfusion on at least two different occasions. Our results clearly indicate the intrafamilial transmission of HCV is not the route of transmission of HCV among Saudis and our results argue against sexual transmission of hepatitis C virus despite a relatively long duration of marriage.
Hepatitis E infection in the UK
Authors: Skidmore S. J. , Sherratt L. M.
Published: December 2007

SUMMARY. A modification of a commercial assay for anti‐HEV to allow detection of specific IgM has been validated. Its use has shown that acute cases of HEV do occur in the UK. To date these have all been patients returning from highly endemic areas.
Whole genome analysis of hepatitis B virus from four cases of fulminant hepatitis: genetic variability and its potential role in disease pathogenicity
Authors: Alexopoulou A. , Karayiannis P. , Hadziyannis S. J. , Hou J. , Pickering J. , Luo K. , Thomas H. C.
Published: December 2007

SUMMARY. The precore stop‐codon variant of hepatitis B virus (HBV) has been associated with fulminant hepatitis but is also found in patients with persistent infection and chronic hepatitis. We have examined the possibility that the severe outcome of infection in patients with fulminant disease may be a result of additional genomic variation. We sequenced the entire HBV genome from three patients of Greek and one patient of Chinese origin with fulminant hepatitis, and from two patients with hepatitis B e antigen (HBeAg) positive chronic infection from the same regions, using direct sequencing of amplified viral DNA. Three of the fulminant cases were infected with the precore stop‐codon variant (HBeAg negative) and the fourth with the wild‐type (HBeAg positive) virus. We compared sequences from our four fulminant isolates, and an additional fulminant isolate reported by others, with HBeAg positive carriers from the same regions and 12 published HBV genomes. There was a higher number of nucleotide and amino‐acid substitutions throughout the HBV genome in the precore variant fulminant sequences than in the wild type. A cluster of mutations previously identified in the X region (126–132) in sequences reported in Japanese patients and encompassing the Enhancer II‐Core Promoter region (1751–1768), were not found in our patients. We conclude that although there are no changes common to all sequences of HBV isolates from fulminant cases, some of these changes are in recognized cis‐acting regulatory elements, whilst others are in the immediate vicinity of such elements. The effect of these mutations on viral genome transcription must now be determined.
Hepatitis E virus infection in patients from Saudi Arabia with sickle cell anaemia and β‐thalassemia major: possible transmission by blood transfusion
Authors: Al‐Fawaz I. , Al‐Rasheed S. , Al‐Mugeiren M. , Al‐Salloum A. , Al‐Sohaibani M. , Ramia S.
Published: December 2007

SUMMARY. The seroprevalence of antibodies against hepatitis E virus (HEV) and hepatitis C virus (HCV) was investigated in Saudi children with sickle cell anaemia (SCA) (50 patients: 28 boys, 22 girls; age range 2–14 years) and P‐thalassemia major (28 patients: 12 boys. 16 girls; age range 2–12 years). The SCA patients were from the Gizan area (South) while the thalassemics were from the Riyadh area (Central province). The prevalence of hepatitis E virus antibody (HEVAb) in patients with SCA (18.0%) and in those with β‐thalassemia major (10.7%) was higher than in the control groups (5.5% and 2.8%) but this did not reach the level of statistical significance. In contrast to the situation with HEV, hepatitis C virus antibody (HCVAb) positivity was significantly higher in patients with SCA (16.0%) and in thalassemics (57.1%) than in the respective control groups. Although the difference in HEV seropositivity between P‐thalassemia major, SCA patients and their respective controls is not statistically significant, the possibility of blood‐borne HEV in the Saudi population cannot be excluded. Further investigations using HEV‐specific polymerase chain reaction techniques are required to confirm whether transmission of HEV through blood preparations or transfusion is possible.
Oxidative burst response of neutrophils primed with PreS1 antigen of hepatitis B virus in patients with chronic hepatitis B and convalescents
Authors: Sulowska Z. , Pietruszynski R. , Dworniak D. , Tchórzewski H. , Sidorkiewicz M.
Published: December 2007

SUMMARY. The pathogenesis of liver damage in the course of hepatitis B virus (HBV) infection depends on the host's specific and non‐specific immune response to various viral antigens. The role of polymorphonuclear neutrophils (PMN) in the natural immune reaction and during secondary microbial infections is well documented. Increased free radical production is associated with many pathological conditions such as shock, ischaemia or chronic inflammatory diseases. We studied the oxidative metabolism of neutrophils in patients with chronic HBV and after recovery (convalescents). The effect of the PreS1 fragment of HBV antigen on some neutrophil functions in vitro was also examined.

There were significant differences in the values of spontaneous and stimulated oxidative burst of neutrophils, measured using luminol‐chemiluminescence, in patients with HBV when compared with the convalescents. PreS1 antigen did not by itself induce the respiratory burst in human neutrophils but it potentiated their response to a second stimulus. Hence we observed a priming of neutrophils, for an enhanced respiratory burst, by PreS1 antigen.
Higher elimination rate of hepatitis C virus among women
Authors: Yamakawa Y. , Sata M. , Suzuki H. , Noguchi S. , Tanikawa K.
Published: December 2007

SUMMARY. The mortality rate from liver disease in H town of the Fukuoka prefecture in Japan is significantly higher in men than in women. To clarify the gender‐related difference, we evaluated subjects with hepatitis B virus (HBV) and hepatitis C virus (HCV) infection in the S area of this town. A total of 824 adults participated in this study, 332 men and 492 women. The incidence of positivity for hepatitis B surface antigen (HBsAg) in serum did not differ significantly between the subjects in the S area (1.9%) and Japanese blood donors (1.5%); however, the incidence of positivity for serum antibody to hepatitis C virus (HCVAb) in the subjects (31.8%) greatly exceeded that in Japanese blood donors (1.3%). The rate of positivity for HCVAb did not differ significantly between men (28.3%) and women (34.1%), but the proportion of serum HCV RNA‐positive to HCVAb‐positive subjects was significantly higher in men (78.2% in men vs 67.3% in women). The incidence of elevated serum alanine aminotransferase (ALT) in subjects positive for serum HCV RNA was also significantly higher in men (77.0% in men vs 55.8% in women). These results suggest that a more frequent elimination of HCV from serum in women may explain the observed lower mortality from liver disease.
Hepatitis C virus genotypes in chronic hepatitis C of children
Authors: Bortolotti F. , Vajro P. , Balli F. , Giacchino R. , Crivellaro C. , Barbera C. , Pontisso P. , Nebbia G. , Zancan L. , Bertolini A. , Alberti A.
Published: December 2007

SUMMARY.Several hepatitis C virus (HCV) genotypes have been recently identified and genotype 1b has been correlated with severe liver disease and a poor response to interferon therapy. HCV infection in children is an interesting model for evaluation of the relationship between HCV genotypes and liver disease, because of its relatively short duration and the infrequent association with confounding cofactors. We have investigated HCV genotypes, using a dot‐blot hybridization assay with genotype‐specific probes, in 36 Italian children with chronic hepatitis C who were otherwise well and had no other underlying disease. Only four patients were symptomatic; liver histology, obtained in 3 3 patients, showed minimal hepatitis in 17 and mild chronic hepatitis in 16. Infection with HCV genotype Ib was found in 55.5% of patients, with a peak prevalence of 83% in children from southern Italy (P < 0.05 vs other regions). The remaining children were infected with HCV genotype la (16.6%), genotype 2 (11.1%). and mixed (10.9%) or undetermined (2.7%) genotypes. In one patient, HCV viraemia was never detected. There was no statistically significant correlation between genotype and age, sex, source of infection, alanine aminotransferase pattern and histological activity index. These results indicate that genotype 1b is widespread among Italian children with chronic hepatitis C, although with significant geographical variations. It is not associated with a more severe liver disease, therefore suggesting that the greater severity of liver disease recently reported in adults could reflect the cumulative effects of disease duration and of interfering cofactors.
Direct microscopy of periodontal pathogens
Authors: Listgarten M. A.
Published: December 2007

Microscopic studies of the periodontal microbiota were among the first to demonstrate the existence of distinctive microbial populations in association with various states of periodontal disease and periodontal health. These findings led to further studies which indicated that conventional mechanical debridement is able to create shifts in the composition of the periodontal microbiota from a disease‐ to a health‐associated one. Investigations of the distribution of certain bacterial morphotypes on selected tooth surfaces confirmed that significant differences exist in the composition of the microbiota between healthy and diseased sites; however, periodontal pockets of similar probing depths in the same subject had microbiotas that were more similar lo one another than to those of comparable pockets in other subjects. These findings lend support to the use of pooled microbial samples from selected surfaces with similar clinical characteristics. On the basis of microbial samples pooled in this manner, it was possible to demonstrate in patients previously treated for periodontitis, that those with elevated proportions of motile rods and spirochetes were more likely to develop subsequent recurrences of periodontitis than subjects with low proportions of these bacterial morphotypes. The predictive reliability of this microscopic assay markedly worsened in patients receiving regularly scheduled periodontal prophylaxes. This observation suggests that caution should be exercised in the utilization of potential diagnostic tests, if the object of the assay can be readily affected by environmental factors that do not affect the subject's susceptibility lo disease in a parallel manner.
Rapid identification of important periodontal microorganisms by cultivation
Authors: Slots Jørgen
Published: December 2007

Two recent developments have made possible rapid isolation and identification of important periodontal species. Selective media have been designed which demonstrate high recovery efficacy of black‐pigmented Bacteroides spp., Actinobacillus actinomycetemcomitans, Eikenella corrodens, Fusobacterium spp., Capnocytophaga spp. and other periodontal bacteria. Presumptive tests for identification of periodontal isolates that are rapid and easy have also been described. Available microbiological methods permit even small microbiology laboratories to screen periodontal samples for suspected pathogens.
Considerations and conclusions
Authors: Krichevsky Micah I. , Krasse Bo
Published: December 2007

Diagnostic microbiological methods play an ever greater role in epidemiological studies and clinical trials related to dental caries and periodontal diseases. Further, such methods can serve the clinician as valuable adjuncts to case history and clinical examination for diagnosis, treatment, and prevention of disease. A variety of diagnostic methods are becoming available and show promise in the hands of individual investigators and clinicians.

The further development of diagnostic microbiological methods will require collaborative studies with careful consideration of basic ecological and epidemiological principles as well as modern technology.
Pyruvate oxidase in Streptococcus sanguis under various growth conditions
Authors: Carlsson Jan , Edlund May‐Britt K.
Published: December 2007

Streptococcus sanguis ATCC 10556 was grown in batch culture under aerobic and anaerobic conditions. The organism was also kept in aerated nitrogen‐ and sugar‐limited continuous cultures. Pyruvate oxidase was induced under aerobic conditions and the highest specific activity of the enzyme was found in aerated batch cultures in the early phase of exponential growth. A steady‐state growth of the organism could not be established in aerated continuous culture, unless catalase was included in the culture medium. In aerated nitrogen‐limited continuous culture with an excess of sugar there was very low pyruvate oxidase activity, and lactate was the only fermentation product. In aerated sugar‐limited continuous culture there was high pyruvate oxidase activity, and acetate was the main fermentation product. This indicated that pyruvate oxidase was the key enzyme in converting pyruvate into fermentation products in the aerated sugar‐limited continuous culture. The pyruvate oxidase reaction requires high concentrations of pyruvate, phosphate and oxygen for maximum velocity. These concentrations are probably never reached intracellularly. The limited supply of substrates may thus be the most important factor in modulating the activity of the enzyme. The enzyme is hysteretic and this may also contribute to the adaptation of the enzyme activity to the metabolic processes of the cell. The combination of pyruvate oxidase and NAD(P)H‐OSCN‐oxidoreductase in S. sanguis and the presence of thiocyanate and salivary peroxidase in saliva may provide an ecological advantage to S. sanguis in habitats exposed to saliva.
Characterization of treponemes isolated from human and non‐human primate periodontal pockets
Authors: Sela Michael N. , Kornman Kenneth S. , Ebersole Jeffrey L. , Holt Stanley C.
Published: December 2007

Treponemes were isolated from ligature induced periodontal pockets of non‐human primates, and from humans with periodontitis. Approximately 39% of the microscopic count were spirochetes from humans, while 65% of the microscopic microbiota was accounted for by spirochetes from non‐human primates. Metabolically, the human treponemal isolates grew on trypticase‐yeast extract based media while the non‐human primate isolates grew only on pectin, glucuronic or galacturonic acids. The end‐products of glucose fermentation by the human treponemes were acetate and propionate, while acetate was produced by the non‐human primate treponemes from pectin. All of the human isolates were indole positive, hemolyzed blood, required serum for growth, but did not require thiamine pyrophosphate (TPP). The non‐human primate treponemes were indole negative, were inhibited in their growth by blood, grew in the absence of serum, and required TPP for growth. PAGE analysis of whole cell proteins revealed three categories of treponemal isolates: (i) human isolates similar to Treponema denticola; (ii) human isolates of small size; and (iii) non‐human primate isolates similar to the pectinolytic treponemes. Serologically, the human treponemal isolates were similar to T. denticola, while the non‐human primate isolates were similar to the pectinolytic treponemes. Four human, 4 non‐human primate, and 4 reference treponemes exhibited a Mol% G + C of their DNA of 40.0‐43.1. The metabolic differences between the human and non‐human primate treponemal isolates may be a reflection of ecological differences in the periodontium of the pathological entities which exist in human and non‐human primates.
Early penetration of Streptococcus mutans into fissure enamel of gnotobiotic rats
Authors: Luoma Heikki , Seppä Liisa , Spets‐Happonen Satu , Tulla Maija , Pelkonen Kai
Published: December 2007

Previous studies have shown that invasion of bacteria into the enamel may take place at a very early phase of the caries process. The present study in originally germ‐free rats was undertaken to observe the ability of Streptococcus mutans to invade rat fissure enamel in initial caries without cavitation. At 24 days, 42 rats were orally infected with S. mutans, while 15 rats were kept uninfected. After feeding on a cariogenic diet for 10 or 21 days the rats were killed, and the upper molars bisected, stained, photographed, and studied for carious changes. The lower molars were split and the cracked surface examined by SEM. In the enamel, subsurface spread and colonization by bacteria was found in all but one case of initial caries. Numerous colonies were seen especially along the dentino‐enamel junction. Thus, S. mutans appears capable of invading rat fissure enamel before carious collapse of the enamel surface.
Growth studies of Wolinella recta, a gram‐negative periodontopathogen
Authors: Gillespie Jane , Holt S. C.
Published: December 2007

The effects of varying concentrations of ammonium formate, fumarate, nitrate, pyruvate and hemin, on growth and end‐product formation in Wolinella recta ATCC 33238 were examined. Mycoplasma broth base supplemented with 30 mM formate and 20 mM fumarate supported growth of W. recta to an optical density of 0.471 with a generation time of 2.15 h. Increasing formate and fumarate concentrations to 150 mM and 75 mM, respectively, resulted in a maximum optical density of 0.600. Neither stirring nor the addition of pyruvate, enhanced growth. Hemin was not required for growth. Growth of W. recta in a defined medium required the addition of at least 0.4% yeast extract. In both complex and defined media, fumarate supported significantly higher maximum optical densities than nitrate. The omission of formate from the growth medium or the adjustment of the pH of the medium to 6.6 resulted in essentially no growth of W. recta. The metabolic products of growth on nitrate and fumarate were nitrite and succinate, with ammonia and hydrogen sulfide also being observed. Growth in all media was accompanied by increases in pH to a maximum of 8.0.
High prevalence of mutans streptococci in a population with extremely low prevalence of dental caries
Authors: Carlsson Peter , Gandour Ibrahim Azis , Olsson Berit , Rickardsson Birger , Abbas Kamal
Published: December 2007

The quantitative distribution of the mutans streptococci was investigated in populations with very low caries prevalence. Three hundred and seven school children from rural Sudan with an estimated age of 12 years were examined for dental status and salivary mutans streptococci. Forty‐two isolates from the salivary cultures were determined to species level by studying the serogroup and biotype. Denial caries in permanent teeth was diagnosed in 12% of the children and the mean DMFT was 0.17 (range 0‐6 DMFT). Caries was confined to fissures. Mutans streptococci were found in 96% of the children and high counts were obtained in 45%. Of 42 isolated strains, 37 belonged to Streptococcus mutans, 5 to Streptococcus sobrinus and none to Streptococcus rattus. The observations show that the mutans streptococci can be widespread in human populations with extremely low prevalence of dental caries and consequently that these bacteria may be readily propagated in human populations without association to a caries‐promoting life style.
Isolation and characterization of low‐pH fluoride‐resistant mutants of Streptococcus mutans
Authors: Lau K. A. , Kral T. A.
Published: December 2007

Stable fluoride‐resistant mutants of Streptococcus mutans GS‐5 were isolated at pH 6.0 and pH 5.0. Fluoride‐resistant mutants isolated at pH 5.0 demonstrated greater resistance to sodium fluoride at pH 7.2 and pH 5.0 than did mutants isolated at pH 6.0. At pH 6.0, resistance levels of the mutants isolated at both pH 6.0 and 5.0 were similar. The average generation time for the mutants isolated at pH 6.0 was 54 min, while the average generation time for mutants isolated at pH 5.0 was 77 min.
Detection of colonies of Bacteroides gingivalis by a rapid fluorescence assay for trypsinlike activity
Authors: Slots Jørgen
Published: December 2007

The synthetic fluorogenic compound carbobenzoxy‐L‐arginine‐7‐amino‐4‐me‐thylcoumarin amide‐HC1 (CAAM) was evaluated for its ability to detect trypsin‐like activity in colonies of Bacteroides gingivalis. CAAM fluoresced with all B. gingivalis isolates tested and did not react with other human black‐pigmented bacteroides species. The utility of the CAAM test for rapid presumptive identification of B. gingivalis is discussed.
Suspected periodontopathic microorganisms and their oral habitats in young children
Authors: Frisken K. W. , Tagg J. R. , Laws A. J. , Orr M. B.
Published: December 2007

Samples of subgingival plaque from 67 children, 5–7 years of age, were examined for the presence of certain suspected periodontal pathogenic species using the conventional technique of anaerobic sonification, dilution and spiral plating. When this technique was compared with a direct plating procedure which involved no preliminary dispersion and dilution of plaque specimens, it was found that the direct method resulted in double the frequency of children in whom black ‐pigmented Bacteroides (BPB) were detected and a 1 (Mimes increase in the number of subjects harbouring Actinobacillus actinomycetemcomitans. Samples from the tongue, tonsils and saliva were also plated using the direct technique. BPB were detected less commonly in the plaque specimens (61.3% of children) than in saliva (89.5%), or on the tongue (86.6%) and tonsils (97.1%). Expressed as percentages of a pooled sample of the total BPB population, the most frequently detected species in plaque were Bacteroides intermedius (44.4%) and Bacteroides melaninogenicus (48.0%). The most prevalent isolate in all other oral sites was B. melaninogenicus. Expressed as percentages of children in whom BPB were detected, the most frequently isolated species from plaque using the conventional dilution technique was B. intermedius (21.3%), whereas other BPB species were present in fewer than 5% of children. Fusobacterium nucleatum and Capnocytophaga species were isolated most frequently from plaque but were also commonly detected in the various other oral sites.
Purification and characterization of a thiol‐protease from Bacteroides gingivalis strain 381
Authors: Ono M. , Okuda K. , Takazoe I.
Published: December 2007

A protease from the culture supernatant of Bacteroides gingivalis 381, which hydrolyzes the chromogenic substrate Na‐benzoyl‐DL‐arginine‐p‐nitroanilide (BAPNA), was partially purified by ammonium sulfate precipitation, gel filtration, and anion exchange chromatography. The molecular weight of this protease was determined by SDS‐PAGE to be ca. 49,000. The optimum pH was around 7.6. The protease was stable at neutral pH and up to 40°C. The isoelectric point was 4.9. The enzyme activity was enhanced by dithiothreitol, L‐cysteine, and 2–mercaptoethanol and inhibited by p‐chloromercuribenzoic acid, N‐ethylmale‐imide, and iodoacetic acid.
Interactions within a collection of eight bacterial stains isolated from a monkey dental root canal
Authors: Dahlén Gunnar , Fabricius Lars , Holm Stig E. , Möller Åke
Published: December 2007

Eight bacterial strains belonging to 6 genera, 2 facultatively anaerobic and 6 obligately anaerobic species, isolated from an autogenously infected dental root canal in a monkey, were used for in vivo and in vitro interference studies. In the tissue cage studies Bacteroides oralis, Fusobaclerium necrophorum, Peptostreptococcus anaerobius and Streptococcus milleri dominated at the end of the experiment. They induced high liters of circulating antibodies in the rabbits. This result was in concordance with the development of a mixed infection in the dental apical region model in monkeys as revealed in previous experiments. In the test tube studies Streptococcus faecalis (Enterococcusfaecalis), a rapidly growing facultatively anaerobic bacterial species, overgrew and survived the tested anaerobes. On agar plates S. milleri was negatively influenced by 3 anaerobic species and S. faecalis. Factors interacting in vitro seemed to play a minor role in vivo. It appears that the tissue cage model offers a valuable in vivo model for studies of mixed anaerobic infections in terms of bacterial interference.
Two functionally different glucose phosphotransferase transport systems in Streptococcus mutans and Streptococcus sobrinus
Authors: Néron Sonia , Vadeboncoeur Christian
Published: December 2007

Abstract Spontaneous phosphotransferase negative mutants of Streptococcus mutans GS5‐2 (mutant GM500) and of Streptococcus sobrinus 27352 (mutant MM202) were isolated by screening for 2‐deoxyglucose resistance using lactose as the growth substrate. Measurements of phosphoenolpyruvate: phosphotransferase activities with isolated membranes and purified Enzyme I and HPr indicated that the mutant strains were defective at the level of membrane components of the phosphoenolpyruvate: mannose phosphotranferase system but still possessed phosphoenolpyruvate: glucose phosphotransferase activity. These results were corroborated by uptake studies performed with resting cells. Our results suggest that glucose is transported by 2 distinct phosphoenolpyruvate: phosphotransferase systems in S. mutans and S. sobrinus, one of which is also capable of transporting mannose. This glucose‐mannose transport system is involved in catabolite repression and inducer exclusion, and controls, by way of these mechanisms, the metabolism of lactose.
Inducing effect of periodontopathic bacteria on interleukin‐1 production by mouse peritoneal macrophages
Authors: Ohmori Yoshihiro , Honda Katsuyuki , Kikuchu Hirotaka , Hanazawa Shigemasa , Amano Shigeru , Hirose Kimiharu , Takeshita Akira , Katoh Tomoko , Kitano Shigeo
Published: December 2007

Sonicated extracts from Bacteroides gingivalis. Fusobacterium nucleatum, Actinobacillus actinomycetemcomitans, and Actinomyces viscosus were found to strongly induce IL‐1 production by mouse peritoneal macrophages as early as 24 h after addition of the sonicates. A significant increase in the IL‐1 production was observed at a dose of 1 μg/ml (dry weight) of the sonicates. The inducing ability was equivalent to 1 μg/ml Escherichia coli lipopolysaccharide. The highest production of IL‐1 was observed in the macrophages treated with A. actinomycetemcomitans. Sonicated extracts of both gram‐negative and gram‐positive bacteria were able to induce the IL‐1 production by macrophages from C3H/HeJ mice, which are LPS low‐responders. These results suggest that periodontopathic bacteria induce IL‐1 production by macrophages. IL‐1 may play an important role in development of periodontal disease.
Antibacterial effect of myeloperoxidase against Streptococcus mutans
Authors: Tenovuo Jorma , Anttila Olli , Lumikari Marianne , Sievers Gunnel
Published: December 2007

Myeloperoxidase‐chloride‐H2O2 antimicrobial system is an integral part of leukocyte defense against pathogenic microorganisms. The system is present in gingival crevicular fluid and in whole saliva and, thus, possibly contributes to the non‐antibody defense in the human mouth. In fact, at physiological concentrations myeloperoxidase‐Cl−‐H2O2 system effectively killed Streptococcus mutans both at acid and neutral pH. However, thiocyanate (SCN−) ions at concentrations similar to those in human saliva abolished this bactericidal action indicating that SCN− rather than Cl− is the physiologic substrate of myeloperoxidase in whole saliva. The peroxidation of SCN− (by myeloperoxidase or salivary peroxidase) yields oxidation products which inhibit the growth and metabolism of S. mutans without notable loss of cell viability. Our results suggest that the presence of SCN− in saliva protects human oral tissues (and bacteria) from highly cytotoxic oxidation products of Cl− and, instead, bacteriostatic and non‐toxic oxidation products of SCN− are generated. In the gingival crevices, however, the SCN−/ Cl− ratio may be too small for effective block of Cl− oxidation by myeloperoxidase, and the oxidation products of Cl−, such as hypochlorite or hypochlorous acid, may contribute to the breakdown of periodontal tissues during inflammation.
The occurrence of Actinobacillus actinomycetemcomitans, Bacteroides gingivalis, Bacteroides intermedius and spirochaetes in the subgingival microflora of adolescents and their relationship with the amount of supragingival plaque and gingivitis
Authors: Ashley F. P. , Gallagher J. , Wilson R. F.
Published: December 2007

The subgingival microflora of 89 children aged 14–15 years was investigated by anaerobic culture and dark‐field microscopy. Actinobacillus actinomycetemcomitans was isolated from 13 subjects and black‐pigmented Bacteroides from 83 subjects. B. intermedius was the most commonly isolated Bacteroides species and was identified in 76 subjects, whereas B. gingivalis was observed in only two subjects. Spirochaetes were found in 79 of the subjects. No statistically significant differences in the clinical condition of the subjects were noted in relation to the presence or absence of A. actinomycetemcomitans. Statistically significant direct relationships were observed between the number of sites with clinical signs of gingivitis and the proportion of spirochaetes and the number and proportion of black‐pigmented Bacteroides in the subgingival sample. These relationships were independent of the effect of the amount of supragingival plaque on either gingivitis or the composition of the subgingival flora.
Intra‐oral distribution of black‐pigmented Bacteroides species in periodontitis patients
Authors: Van Winkelhoff A. J. , Van der Velden U. , Clement M. , De Graaff J.
Published: December 2007

In this study the occurrence of black‐pigmented Bacteroides on oral mucous membranes and in saliva was investigated. For this purpose untreated adult periodontitis patients were selected on the basis of clinical parameters. Bacteroides gingivalis was isolated from the subgingival area of all 8 patients. Other sites from which B. gingivalis was recovered were the tonsillar area, the gingiva and the tongue. Six of the 8 patients had B. gingivalis in saliva in numbers ranging from 6 × 106 to 20 × 106/ml. Bacteroides intermedius was also widespread through the oral cavity, including the saliva. The results show that these black‐pigmented Bacteroides species do occur outside the periodontal pocket and that the intra‐oral spread of these bacteria can take place via saliva.