A chymotrypsinlike protease with an Mr of 95,000 was extracted from Treponema denticola ATCC 35405 and was partially purified by preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The proteolytic activity was detected in an electrophoretogram containing polyacrylamide that was conjugated to bovine serum albumin. A single band of activity was detected when the T. denticola extract was solubilized and electrophoresed in the presence of sodium dodecyl sulfate. No activity was found in extracts of Treponema vincentii. The enzyme hydrolyzed transferrin, fibrinogen, al-antitrypsin, immunoglobulin A, immunoglobulin G, gelatin, bovine serum albumin, and a synthetic peptide containing phenylalanine. It did not degrade collagen or synthetic substrates containing arginine or proline. For the hydrolysis of azocoll, the pH optimum of the enzyme was 7.5. Heating at temperatures above 50°C destroyed the activity. Reducing agents and the chelators EDTA and ethylene glycol-bis(O-aminoethyl ether)-N,N,N',N'-tetraacetic acid increased the enzyme activity, while phenylmethylsulfonyl fluoride, L-1-tosylamide-2-phenylethyl chloromethyl ketone, sulfhydryl reagents, and human serum reduced activity. The ability of the enzyme to hydrolyze a number of humoral proteins suggests that it may be involved in spirochete invasiveness and tissue destruction. * Corresponding author.35405 that has the ability to hydrolyze many functionally important serum and tissue proteins. MATERIALS AND METHODSBacterial strains and culture conditions. T. denticola ATCC

Dark-field microscopy of blood from healthy individuals revealed the existence of pleomorphic microorganisms. These bacteria exhibited limited growth and susceptibility to antibiotics and could be detected by fluorescent in situ hybridization and flow cytometry. They were further characterized by analysis of their 16S rRNA and gyrB genes.In our search for spirochetes involved in Alzheimer's disease (13), we observed pleomorphic bacteria in the blood of healthy human subjects by dark-field microscopy. This was a surprising finding since it is generally acknowledged that the bloodstream in healthy humans is a sterile environment (7) except when there is a breach in the integrity of the tissue membranes (6). However, the concept of the occurrence of bacteria in the blood of healthy humans is now more plausible because of cultivation-independent laboratory approaches. The main techniques employed in such studies include PCR amplification and sequencing of the16S ribosomal DNA (rDNA). These methods have revealed the presence of a wide diversity of microorganisms in the environment, and indeed within the human body (12). In this report we present evidence based on molecular phylogenetic techniques and light and electron microscopy, as well as other conventional microbiological methods, for the existence of a population of bacteria in healthy human blood. In view of the apparent controversial nature of our findings, it was encouraging to note the recent report of Nikkari et al. (14), who detected blood-associated bacterial rDNA sequences by using real-time PCR methods and a probe targeting conserved regions of bacterial 16S rDNA, and an earlier report by Tedeshi et al. (16) on the presence of pleomorphic bacteria as intraerythrocytic parasites in clinically healthy human subjects.For light microscopic examination, blood samples from 25 healthy volunteers were drawn in a Vacutainer tube with no anticoagulants (Becton Dickinson, Franklin Lakes, N.J.); blood was drawn in the conventional manner involving antisepsis of the skin and avoidance of any introduction of external microorganisms by contamination. (Since external contamination was always a possibility, particular care and precaution were exercised at all times to avoid this. The specific procedures, as well as appropriate controls, are specified throughout the text.) A wet mount of the serum from the clotted blood of each sample, fresh or incubated at 30°C for between 5 to 7 days, was examined by dark-field microscopy (Leitz Dialux 20) for pleomorphic bacteria.For PCR amplification, a 0.5-ml aliquot of incubated blood containing pleomorphic bacteria was used for conventional extraction of DNA by the method of Higuchi (11). Three microliters of the extract was used for DNA amplification by the method of Edwards et al. (8) using the forward primer BSF8/20 (5Ј-AGAGTTTGATCCTGGCTCAG-3Ј) and the reverse primer BSR1541/20 (5Ј-AAGGAGGTGATCCAGCCGCA-3Ј). Thirty cycles of PCR were performed, with 1 cycle consisting of the following steps: (i) denaturation (1 min at 94°C), (i...

All oral spirochetes are classified in the genus Treponema. This genus is in the family Spirochaetaceae as in Bergey's manual of systematic bacteriology. Other generic members of the family include Spirochaeta, Cristispira and Borrelia. This conventional classification is in accord with phylogenetic analysis of the spirochetes based on 16S rRNA cataloguing. The oral spirochetes fall naturally within the grouping of Treponema. Only four species of Treponema have been cultivated and maintained reliably: Treponema denticola, Treponema pectinovorum, Treponema socranskii and Treponema vincentii. These species have valid names according to the rules of nomenclature except for Treponema vincentii, which only has had effective publication. The virulence factors of the oral spirochetes updated in this mini-review have been discussed within the following broad confines: adherence, cytotoxic effects, iron sequestration and locomotion. T. denticola has been shown to attach to human gingival fibroblasts, basement membrane proteins, as well as other substrates by specific attachment mechanisms. The binding of the spirochete to human gingival fibroblasts resulted in cytotoxicity and cell death due to enzymes and other proteins. Binding of the spirochete to erythrocytes was accompanied by agglutination and lysis. Hemolysis releases hemin, which is sequestered by an outer membrane sheath receptor protein of the spirochete. The ability to locomote through viscous environments enables spirochetes to migrate within gingival crevicular fluid and to penetrate sulcular epithelial linings and gingival connective tissue. The virulence factors of the oral spirochetes proven in vitro underscore the important role they play in the periodontal disease process. This role has been evaluated in vivo by use of a murine model.

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A large single-institution study of recurrence in BPPV is presented along with Kaplan-Meier disease-free survival curves. Female sex and history of previous BPPV were associated with increased recurrence, while previously suspected risk factors for recurrence including history of Menière's disease, diabetes, and trauma were not. Remote recurrence is more likely to involve the contralateral ear than early recurrence. These data solidify the expected course of treated BPPV allowing for improved clinical care and patient counseling.

By the combined use of membrane filters and the antibiotic rifampin, intermediate‐size anaerobic spirochetes from periodontal pockets were routinely selected and separated from other oral bacterial contaminants. Electron microscopy of six newly isolated strains showed that they belong to the genus Treponema. The organisms had generation times of about twelve hours; they produced only acetic acid when glucose was used as the carbohydrate in the medium Serum, volatile fatty acids, and thiamine pyrophosphate could be omitted individually as supplements from the growth medium, but sodium bicarbonate was absolutely essential for growth. These treponemes could be maintained by monthly transfers into fresh medium, by freezing in glycerol‐broth medium or by lyophilization.

Repeated measurements of attachment level appear to be important assessments in periodontal clinical trials, yet the lack of reliability for this assessment creates measurement error which in turn demands increased sample sizes or reduces the power of the test. A plastic occlusal stent has been developed as a fixed reference point to assess changes in probing depths over time and thus reflect differences in attachment levels. The advantages of this system over traditional methods have not been measured. The purpose of this study was to determine intra- and interexaminer reliability for probing depths from the stent and the CEJ. Paired measurements of attachment level using the stent produced correlation coefficients for inter- and intraexaminer readings of 0.84 and 0.76, respectively. For subgingival cementoenamel (CEJ) measurements, lower coefficients of 0.71 and 0.59 were found for inter- and intraexaminer paired readings, respectively. Thus, measurements using the stent appear to be more reliable than subgingival CEJ readings.

Spirochetes are thought to remain motile in environments (such as intercellular spaces) that immobilize extracellularly flagellated eubacteria. This attribute suggests that the viscosity of the milieu is of importance to locomotion. We sought to determine the interdependence of oral spirochete locomotion with media viscosity. Video time-lapse microscopy using darkfield optics was used. The motility of the spirochetes in media of different viscosities (various concentrations of Noble agar) was measured. Treponema denticola exhibited the fastest speed (18.7 +/- 4.4 microns/min) at a viscosity of 30 mPa.s. The highest speeds for Treponema vincentii and Treponema socranskii were 41.9 +/- 14.9 and 33.4 +/- 13.2 microns/min, respectively, at 88 mPa.s. These data show that optimal migration of spirochetes is viscosity-dependent. The results support the hypothesis that such viscosity-dependent locomotion could be a virulence factor that enables oral spirochetes to initiate and sustain periodontal disease.