The survival of oral streptococci on human skin and its implication in bite-mark investigation.

Ten-microlitre aliquots of whole saliva applied to human skin were sampled for periods up to 6.25 h. The rate of loss of recoverable bacteria was 45-50% per hour. After 6.25 h, viable oral streptococci could be recovered. The implications for using a "fingerprint" typing method for these bacteria with regard to the identification of bite-marks are discussed.

Behavior of hyaluronic acid from gingival epithelium and connective tissue on the analytical ultracentrifuge.

The molecular weights of hyaluronic acid (HA) isolated from separated specimens of human gingival epithelium and connective tissue as well as standard hyaluronic acid preparations have been estimated. The values were determined following substitution of sedimentation values into a previously determined empirical relationship between the reciprocal of the sedimentation coefficient at zero concentration (S-1)0 and molecular weights estimated by sedimentation-diffusion (MsD). The values of (S-1)0 for connective tissue and standard low-molecular weight HA preparations obtained by linear regression of all points indicated molecular weights (MsD) of 340,000 and 205,000 respectively. However, epithelial and standard high-molecular weight HA behaved differently during ultracentrifugation generating a curvilinear relationship between s-1 and concentration. Nevertheless linear extrapolation of a line of best fit of the very lowest concentrations (those which approached zero concentration) provided molecular weight estimates of 860,000 and 2,500,000 respectively. Moreover, similar treatment of s-1 values derived from the previously published data of Laurent, Ryan and Pietruszkiewicz has validated the use of linear regression of s-1 at the lower concentrations alone, to calculate high-molecular weight HA. The curvilinear relationship for s-1 throughout the whole concentration range (0.15-2.3 mg/ml) has been regarded only as a qualitative indication that the HA samples are of relatively high-molecular weight, while a straight line through such data points implies a qualitatively lower molecular weight for HA.

The active role of gingival proteoglycans in periodontal disease.

The quantitatively major extracellular non-fibrous macromolecules of human gingivae are the proteoglycans. This class of macromolecules have been considered to be paramount in maintaining many tissue functions and are therefore presumably of prime importance in regulating the physiology of the gingivae which in turn regulates its structural integrity. Such an active role for the proteoglycans has been hitherto widely ignored in the standard dental texts, which assume the intercellular material of gingivae to be "inert" and "amorphous". We pose a question: "Is it possible that the intercellular proteoglycans of gingival epithelium and connective tissue play a major role in the regulation of the initiation and sequelae of periodontal disease?" Consequently, we hypothesize that, in gingivae affected by the destructive inflammatory processes seen in periodontal disease, the status of the extracellular proteoglycans of the gingival epithelium specifically determines the rate of diffusion of extraneous inflammagens or tissue destructive enzymes from the oral cavity. By analogy, the response of the underlying connective tissue to these solutes diffusing into it will be regulated by the state of its extracellular proteoglycan and indeed, may in turn, effect the maintenance of the closely apposed epithelial integrity.

Proteoglycans of human gingival epithelium and connective tissue.

Proteoglycans extracted from separated specimens of healthy human gingival epithelium and from connective tissue have been purified. The epithelial proteoglycans fractionated as a single included peak on Sepharose 4B-CL and contained heparan sulphate and dermatan sulphate glycosaminoglycans. The connective-tissue proteoglycans separated into three major populations on Sepharose 4B-CL, one of which was excluded from this gel under associative conditions (0.5 M-sodium acetate, pH 7.4). Subsequent fractionation of the excluded material under dissociative conditions (4 M-guanidinium chloride/0.05 M-sodium acetate, pH 7.4) revealed an absence of any aggregate formation of molecules within this population. The connective-tissue proteoglycans contained heparan sulphate, dermatan sulphate and chondroitin 4-sulphate, the proportions of which varied with the molecular size of the proteoglycans. Amino acid analysis of the protein cores of gingival-epithelial and connective-tissue proteoglycans revealed differences that were similar to the differences described between other types of proteoglycans such as those from skin.

Proteoglycans in human gingiva: molecular size distribution in epithelium and in connective tissue.

The major extracellular, non-fibrous macromolecules in human gingiva are proteoglycans. These sulphated, uronic acid-containing macromolecules are synthesized in vitro by both gingival epithelium and its underlying connective tissue. Biochemical analyses were carried out on cultured human predominantly gingival epithelium and predominantly connective tissue in media containing appropriate radioactive precursor molecules. The proteoglycans were extracted with salt solutions of varying concentration and characterized by means of column chromatography and liquid scintillation counting. The major differences noted between the macromolecules extracted from these closely apposed regions were molecular size, and the ability or not to form large self-aggregatable macromolecules. In general, the epithelial proteoglycans are larger than connective tissue proteoglycans. Proteoglycans from gingival epithelium are able to self-aggregate to form large macromolecules with mol. wt in excess of 2 X 10(6) which are essential for the maintenance of tissue integrity.

Molecular weight estimation of sulfated glycosaminoglycans in human gingivae.

The number-average molecular weights of human gingival epithelium and connective tissue glycosaminoglycans (GAG) have been determined. Radioactive labelled GAG were extracted from separated gingival epithelium and connective tissue following alkaline degradation of the tissue in the presence of tritiated sodium borohydride. They were identified by electrophoresis as heparan sulfate (HS), hyaluronic acid (HA), dermatan sulfate (DS) and chondroitin 4-sulfate (ChS-4). Following densitometric quantitation of the sulfated GAG (HS, DS and ChS-4), the amount of radioactivity associated with each species was determined by liquid scintillation of each band staining positively for these GAG. The number-average molecular weights for each GAG were determined by end group analysis. The values obtained for each sulfated GAG indicated a degree of similarity in molecular weight distribution between the two tissue types ranging from 15,000 to 27,000.

Glycosaminoglycans of human gingival epithelium and connective tissue.

The glycosaminoglycan (GAG) components of the proteoglycans (PG) in the epithelial and connective tissue extracellular compartments of human gingivae have been determined. Following proteolytic digestion of the separated tissues. GAG were identified electrophoretically. These were hyaluronic acid (HA), heparan sulfate (HS), dermatan sulfate (DS) and chondroitin-4 sulfate (ChS-4). Neither ChS-6 nor keratan sulfate (KS) was observed. Confirmation of the nature of the molecular species was obtained by the use of Streptomyces hyaluronidase, chondroitinase AC II and degradation with nitrous acid. Quantitatively, the major GAG component of the epithelial specimens was HS (59.6%), whilst DS (60.6%) constituted the major GAG of human gingival connective tissue.

Proteoglycans from adult human gingival epithelium.

Proteoglycans extracted from human gingival epithelium appear to contain a proportion of molecules that will interact with hyaluronic acid to form macromolecular aggregates. In contrast, proteoglycans from underlying connective tissue behaved differently. The interactions of hyaluronic acid with proteoglycans from either epithelium or cartilage may be similar, but not necessarily identical.