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R J Genco

Publications and source records attributed to R J Genco.

At least 253 records · Page 14Linked to original sources
PubMed1979

Direct hemagglutination technique for differentiating Bacteroides asaccharolyticus oral strains from nonoral strains.

A simple and economical method for differentiating Bacteroides asaccharolyticus of oral sources from nonoral sources is described. The present data indicate that oral strains of B. asaccharolyticus strongly agglutinate sheep erythrocytes, whereas isolates from various nonoral sites typically are devoid of hemagglutination activity. The direct hemagglutination test may aid in determining the source of B. asaccharolyticus present in an infection, and thus the procedure has potential value as a means of biotyping.

Animals↗
PubMed1979

Periodontal therapy in humans. I. Microbiological and clinical effects of a single course of periodontal scaling and root planing, and of adjunctive tetracycline therapy.

The present results showed that maarked and long-lasting changes in the subgingival microflora associated with periodontal disease could be achieved by a single course of periodontal treatment. Immediately following therapy, the total number of subgingival organisms decreased 10- to 100-fold and the proportions of cultivable Gram negative organisms and anaerobic organisms generally decreased 3- to 4-fold or more. After treatment, most periodontal pockets were populated by a scant microflora predominated by facultative Actinomyces and Streptococcus species. The kinetics of the subgingival bacterial recolonization revealed that the total cell counts and the proportions of spirochetes and Capnocytophaga species did not reach their pretreatment levels even after 6 months. Other Gram negative anaerobic species returned to pretreatment proportions after 3 to 6 months. Several Gram positive species exhibited higher posttreatment than pretreatment proportions throughout the 6 months study. The microbiological shifts paralleled significant changes in the clinical status of the periodontal tissues. Following therapy, the periodontal pocket depths decreased generally 1 to 4 mm, the gingival inflammatory index, the gingival fluid flow, and the suppurative index were generally lower, and nine of 33 test pockets examined showed apposition of alveolar bone. The microbiological and clinical changes described were exhibited by two patients treated with periodontal scaling and root planing alone and by two patients treated with the adjunctive use of systemic tetracycline therapy. In two other patients, mechanical periodontal therapy only slightly reduced the total number of subgingival organisms and the proportions of spirochetes and other Gram negative anaerobic rods. A shift in the subgingival microbial composition was achieved in these two patients after tetracycline therapy. The following model for treatment of periodontal disease is proposed: (1) Conventional therapy including thorough periodontal scaling and root planing; (2) Monitoring the subgingival flora and the clinical course; and (3) Use of antimicrobial therapy in refractory cases. Further studies are needed to develop means for rapid identification of refractory patients, and to determine the optimal antimicrobial agent, the optimal route of administration, and the optimal dosage regime.

Actinomyces↗
PubMed1979

Inhibition of lymphocyte blastogenesis by C3c and C3d.

The C3 cleavage products C3c and C3d were tested for their ability to alter the immunoproliferative response of human peripheral mononuclear cells to the antigens SLO and SK-SD, and to the mitogens PHA and PWM. It was found that both C3c (30 to 120 micrograms/ml) and C3d (10 to 40 micrograms/ml) inhibited lymphocyte blastogenesis in the presence on antigens but not mitogens, when cells were cultured in either autologous plasma or FCS. Similarly, the response to antigens of cell populations enriched for T lymphocytes was inhibited, whereas the response to optimal or suboptimal doses of mitogens was unaffected. When nonadherent (NA) cells were reconstituted with increasing numbers of adherent (AD) cells to potentiate the proliferative response of NA cells to the antigen SLO, the addition of either C3c or C3d abolished the potentiation of the response at low levels of reconstitution. However, at given dose of C3c or C3d, addition of excess AD cells could restore the proliferative response. These results suggest that both C3c and C3d can inhibit T cell proliferation in response to antigen and that they may act at the level of the monocyte-T lymphocyte interaction to modulate cellular immune responses.

Antibodies↗
PubMed1978

In vitro antiplaque properties of a series of alkyl bis(biguanides).

A series of eight alkyl bis(biguanide) analogues of alexidine, N,N''''-1,6-hexanediyl bis[N'-(2-ethylhexyl)imidodicarbonimidic diamide] (1), was prepared. Five of these analogues constituted a series isolipophilic with 1 but with varying bridge length between biguanide moieties. The compounds were evaluated in vitro for antibacterial and antiplaque properties against Streptococcus mutans, Actinomyces viscosus, and Actinomyces naesludii. One analogue, N N,''''-1,6-hexanediyl bis[N'(n-octyl)imidodicarbonimidic diamide], appeared to be more effective than either 1 or chlorhexidine against this spectrum of dental plaque forming microorganisms.

Actinomyces↗
PubMed1978

The in vitro inhibition of microbial growth and plaque formation by surfactant drugs.

Several cationic, mixed and amphoteric surfactants were tested for their antimicrobial activity and ability to inhibit the formation of in vitro plaque by oral microorganisms. All had antimicrobial activity against Actinomyces viscosus. Actinomyces naeslundii and Streptococcus mutans. Cationic surfactants were comparable to chlorhexidine in antimicrobial activity but were less effective in inhibiting plaque formation. Amphoteric surfactants were less effective than other detergents in antibacterial activity and had very limited capacity for the inhibition of plaque formation. Comparison of drug structure provides evidence that surfactant substantivity to saliva-coated enamel is a cation active process. Saliva was found to have an antagonistic effect on the activity of cetylpyridinium chloride but not on Triburon.

Actinomyces↗
PubMed1978

Complement activity in middle ear effusions.

Evidence for complement utilization in middle ear fluids (MEF) from patients with otitis media with effusion was sought. It was found that cleavage products of C3, C4 and Factor B could be demonstrated immunochemically in MEF, and that native C3 was present in much lower concentrations than other proteins, relative to their serum concentrations. Haemolytic assays for C1-C5 showed that early complement components are inactivated in MEF. Potential mechanisms for complement utilization in MEF are discussed.

Child↗
PubMed1977

Comparison of antiplaque agents using an in vitro assay reflecting oral conditions.

An in vitro assay is described using saliva-treated bovine enamel slabs for determining the potential of chemotherapeutic agents to adsorb to tooth surfaces and act against plaque-forming bacteria. Chlorhexidine was found to inhibit the formation of in vitro plaque by Actinomyces viscosus, A naeslundii, Streptococcus mutans and S sanguis. Actinobolin was found to have marked antibacterial properties but limited adsorptive qualities.

Actinomyces↗
PubMed1977

Gingival fluid and serum in periodontal diseases. I. Quantitative study of immunoglobulins, complement components, and other plasma proteins.

1. Gingival fluid from severely inflamed periodontal tissue represents a 15 to 30% dilution of serum with respect to the proteins studied, with the exception of C3 and in some subjects, C4. 2. A marked decrease in C3 levels is found in most, if not all, gingival fluids, and a marked decrease of C4 levels is found in some gingival fluids. This suggests that complement might be activated during periodontal inflammation. 3. The concentrations of proteins in the gingival fluid are not related to their molecular weight.

Blood Proteins↗
PubMed1977

Gingival fluid and serum in periodontal diseases. II. Evidence for cleavage of complement components C3, C3 proactivator (factor B) and C4 in gingival fluid.

1. C3 activation products C3c and C3d can be demonstrated in gingival pocket fluid from patients with severe periodontitis. 2. Quantitatively, C3d levels in GF are comparable to levels attained consequent to immune-complex and tryptic activation of human serum. 3. The alternate pathway of complement activation occurs in the periodontal pocket, as demonstrated by conversion of C3 proactivator (Factor B) to C3-activator Bb. 4. C4 is present in an altered form in some, but not all, GF's. This form is electrophoretically similar to that generated from serum by C1s and several proteolytic enzymes.

Complement C3↗
PubMed1977

In vitro antiplaque effects of antiseptic phenols.

Several phenols known to be antiseptics were tested in vitro for their ability to adsorb to saliva-coated enamel and subsequently inhibit plaque formation. 3,5,4'-tribromosalicylanilide was found to be effective against growth and plaque formation of A viscosus, A naeslundii, S mutans and S sanguis. Dibromsalicil was effective against A viscosus. The other phenols (hexylresorcinol, thymol, phenylphenol and zinc phenolsulfonate) did not inhibit in vitro growth or plaque formation.

Animals↗
PubMed1977

Lymphoproliferative response during resolution and recurrence of naturally occurring gingivitis.

The lymphocyte blastogenic response in humans to oral bacterial antigens was investigated during resolution and recurrence of naturally occurring gingivitis. The following conclusions were drawn: 1. Actinomyces and Fusobacterium and the host responses they evoke, are associated with gingival inflammation. 2. The magnitude of the blastogenic response to these antigens is directly related to the severity of gingival inflammation. 3. Scaling may cause a transient rise in the blastogenic response. 4. Conservative therapy not only improves the clinical state of gingival health, but also interrupts a possible pathogenic mechanism of periodontal disease.

Actinomyces↗
PubMed1977

Combined micromanipulation, culture and immunofluorescent techniques for isolation of the coccal organisms comprising the "corn cob" configuration of human dental plaque.

The present study describes methods to 1) selectively isolate Corn Cob Configurations (CCC) from dental plaque by micromanipulation; 2) obtain pure cultures of the coccal constituent; 3) determine by immunofluorescent procedure which organisms originated from the CCC. Using a de Fonbrune micromanipulator, CCC specimens were isolated from supragingival plaque samples. The viability of one specimen thus obtained was established by observing growth on a slide culture. One set of CCC specimens was transferred to broth and incubated aerobically immediately upon collection. Another set was transferred to prereduced transport medium and later plated on blood agar for aerobic and anaerobic culturing. A total of 10 coccal strains were thus isolated. Antisera produced in rabbits against the 10 strains were used to localize these coccal organisms on plaque smears by using the indirect fluorescent antibody technique. Of the 10 antisera tested, 2 produced against streptococcal strains consistently gave a positive immunofluorescent reaction with the coccal component of CCC in the plaque smears; the corresponding streptococci were therefore considered to be CCC forming strains in vivo.

Bacteria↗