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Biomedical subjects

R J Genco

Publications and source records attributed to R J Genco.

At least 235 records · Page 13Linked to original sources
PubMed1981

In vitro evaluation of antibiotics in the treatment of periodontal disease.

To assess the antibiotic sensitivity of subgingival microflora, chloramphenicol sodium succinate, clindamycin hydrochloride hydrate, disodium carbenicillin, doxycycline hyclate, erythromycin, minocycline hydrochloride, penicillin -G, spiramycin adipate, tetracycline hydrochloride and metronidazole were examined. Eleven patients with periodontitis were selected for sampling. Subgingival plaque samples were taken from three sites on each patient. Anaerobic incubation of the plaque samples for ten days was made on the blood agar plates which contained 0.1 microgram/ml and 5 microgram/ml of each antibiotic substance, respectively. According to the results of viable counts on the plates, it was determined that penicillin, tetracycline, doxycycline, and minocycline were most effective antibiotics with which to control the periodontal plaque organisms. Resistant organisms against those four antibiotics were generally Streptococcus species. "anaerobic vibrios", and Veillonella parvula. Some of the oral anaerobic isolates were also tested against all antibiotics at the concentration of 1 microgram/ml of each. Minocycline and clindamycin were the two most effective antibiotics against anaerobic subgingival purified strains and chloramphenicol was the least effective.

Anti-Bacterial Agents↗
PubMed1980

Surface thermodynamics of normal and pathological human granulocytes.

Surface tensions of normal and pathological granulocytes were determined by (1) adhesion to solid substrates of different surface tensions while suspended in liquid media of different surface tensions, and by (2) measurement of cell-liquid-vapor contact angles obtained with sessile drops of saline water on cell monolayers. The results obtained by the two different methods were in close conformation with one another. With the cell adhesion method some residual leukocyte adhesion still persists even under conditions where there no longer is a van der Waals attraction between cells and solid substrate. At low ionic strength and by the abolishment of all multivalent cations through the admixture of EDTA, that residual cell adhesion virtually disappears (with normal as well as with pathological granulocytes), indicating that the earlier residual cell adhesion did indeed arise from electrostatic interactions mediated by multivalent cations (probably Ca2+). Comparison of the capacities for engulfment and the surface thermodynamics data of normal and pathological granulocytes obtained in this study leads to the novel observation that the phagocytic episode from half to complete engulfment of bacterial particles by granulocytes appears to be the crucial step from the thermodynamic point of view.

Cell Adhesion↗
PubMed1980

In vitro antimicrobial susceptibility of Actinobacillus actinomycetemcomitans.

The agar dilution technique was used for determination of the antibiotic susceptibilities of 57 oral isolates and 2 nonoral isolates of Actinobacillus actinomycetemcomitans. Tetracycline, minocycline, and chloramphenicol inhibited more than 96% of the strains tested at a concentration of less than or equal to 2 micrograms/ml; 89% of the strains were inhibited by 2 micrograms of carbenicillin per ml. The other antimicrobial agents tested were less active. Approximately 10% of the A. actinomycetemcomitans strains were resistant to ampicillin, erythromycin, and penicillin G at concentrations of 32 to 64 micrograms/ml. These data suggest that tetracycline and minocycline may be valuable drugs in the treatment of A. actinomycetemcomitans infections.

Actinobacillosis↗
PubMed1980

Neutrophil chemotaxis dysfunction in human periodontitis.

Polymorphonuclear leukocyte (PMNL) chemotaxis studies of 32 patients with localized juvenile periodontitis (periodontosis or LJP), 10 adult patients with a history of LJP (post-LJP), 8 patients with generalized juvenile periodontitis (GJP), and 23 adults with moderate to severe periodontitis were performed: (i) to determine the prevalence of a PMNL chemotaxis defect in a large group of LJP patients; (ii) to study PMNL chemotaxis in patients with other forms of severe periodontal disease; and (iii) to determine if the PMNL chemotaxis defect seen in LJP patients is a cell-associated defect or is mediated by humoral factors. The effect of periodontal treatment on PMNL chemotaxis was studied in nine LJP patients. The chemotactic response was measured with the Boyden chamber procedure, and patient's peripheral PMNL were compared with those of control subjects, using endotoxin-activated serum, bacterial factor, N-formylmethionyl-leucylphenylalanine, and leukocyte-derived chemotactic factor as the standard chemoattractants. Based upon statistical analysis of chemotaxis assays, most carried out on at least two and often three or more separate occasions, 26 of 32 LJP patients, 7 of 10 post-LJP patients, and 5 of 8 GJP patients exhibited cellular defects of chemotaxis, whereas only 2 of 23 of the patients with adult periodontitis exhibited depressed chemotaxis. Elevated PMNL chemotaxis was occasionally found in subjects with juvenile periodontitis (2 of 32 with LJP and two of eight with GJP); however, it was found in a significant number (10 of 23) of patients with adult periodontitis. In eight of nine LJP patients, depressed PMNL chemotaxis was observed before and after periodontal therapy. The results indicate that the PMNL chemotaxis defect observed in juvenile periodontitis is due to a cell-associated defect of long duration. These studies suggest that the PMNL plays a major protective role against periodontal infection and that the cellular chemotactic defects and may predispose subjects to LJP.

Adolescent↗
PubMed1980

Purification and characterization of a rhamnose-containing cell wall antigen of Streptococcus mutans B13 (serotype d).

A rhamnose-containing polysaccharide (RCP) was extracted and purified from cell walls of Streptococcus mutans B13 (serotype d) and was chemically and immunologically characterized. Walls were initially extracted with 5% trichloroacetic acid at 4 degrees C to remove the serotype antigen and were then sequentially extracted with increasing concentrations of hot acid. Extracts lacking galactose were combined and chromatographed on a column of diethylaminoethyl--Sephadex A25. The purified RCP contained 90% carbohydrate, 1.4% protein, and 0.16% phosphorus. Analysis by gas chromatography indicated that the RCP was composed of rhamnose and glucose in a 1.6:1 ratio. RCP was immunogenic in rabbits when animals were immunized with whole cells or cell walls. Antisera prepared against partially extracted cell walls of B13 appeared specific for RCP. These sera were not reactive with purified serotype d antigen or lipoteichoic acid in passive hemagglutination assays or by agar gel diffusion. The RCP appeared to be a cell wall polysaccharide that was both chemically and immunologically distinct from the serotype d antigen.

Animals↗
PubMed1980

Characterization of tufted streptococci isolated from the "corn cob" configuration of human dental plaque.

Streptococci isolated from "corn cob" configurations of human dental plaque possess a polar fibrillar tuft extending 100 to 150 nm from one pole of the cell. The two strains studied were physiologically related to the Streptococcus sanguis-Streptococcus mitior group and were most similar to Streptococcus mitis ATCC 903. The corn cob streptococci were serologically related to S. sanguis serotype 1. The polar tuft contained at least two antigenically distinct components, one serologically related to the glycerol phosphate backbone of teichoic acid. The other was an electrophoretically slow-moving antigen similar to a component of S. mitis ATCC 903. It is suggested that the corn cob streptococci in vivo adhere to Bacterionema matruchotii by means of the polar tuft.

Animals↗
PubMed1980

Immunological properties of Actinomyces viscosus: comparison of blastogenic and adjuvant activities.

A water-soluble extract of Actinomyces viscosus was tested for its capacity to induce deoxyribonucleic acid synthesis in spleen cells from normal mice and to augment the in vitro antibody-forming cell (AFC) response to the T-cell-dependent antigen, sheep erythrocytes (SRBC) by T-cell-deficient adherent spleen cell monolayers from the same mice. Our results indicated that the water-soluble extract induced an in vitro blastogenic response, as assessed by tritiated thymidine incorporation into mouse spleen cells. The water-soluble extract also augmented the antibody response to SRBC. However, after fractionation of the water-soluble extract on Biogel P-300, not all of the fractions induced a blastogenic response and augmented an AFC response to SRBC. This difference in the ability of A. viscosus fractions to induce in vitro responses suggests that the water-soluble extract has multiple immunological properties. Chemical analysis of the water-soluble extract indicated an enrichment for amino acids and amino sugar common to peptidoglycan.

Actinomyces↗
PubMed1980

Lymphoproliferative responses to oral bacteria in humans with varying severities of periodontal disease.

We assessed in vitro the lymphocyte blastogenic resp onsess of peripheral blood lymphocytes to antigen extracts of a large battery of oral microorganisms in a population of humans with varying severities of periodontal disease. When the magnitudes and frequencies of statistically positive blastogenic responses to various oral microorganisms were compared, three general patterns emerged. The Actinomyces species proved to be potent stimulators of lymphocyte blastogenesis in most subjects tested, whereas Streptococcus sanguis, Campylobacter, and Eikenella corrodens stimulated few individuals. The response to these organisms correlated poorly with the severity of periodontal disease in the tested patients. However, several gram-negative anaerobic organisms, including Bacteroides asaccharolyticus and Treponema denticola, elicited statistically more frequent positive response in subjects with destructive periodontitis compared with patients with gingivitis. These results, taken together with recent microbiological findings, suggest that the specificity of the lymphocyte blastogenic response to antigens of oral bacteria correlates with the presence of these organisms in the subgingival microflora during various periodontal disease states.

Actinomyces↗
PubMed1980

Antigenic studies of oral and nonoral black-pigmented Bacteroides strains.

Antigens of several oral and nonoral strains of Bacteroides asaccharolyticus (proposed classification of oral B. asaccharolyticus, Bacteroides gingivalis), Bacteroides melaninogenicus subsp. intermedius, B. melaninogenicus subsp. melaninogenicus, and B. melaninogenicus subsp. levii were identified in soluble preparations obtained by sonication, autoclaving, and NaOH treatment of whole bacterial cells. The sonicate preparations contained the most complete representation of soluble antigens using antisera to the whole organism in gel precipitation tests. Among strains of B. melaninogenicus subsp. intermedius many common antigens were detected, and no consistent antigenic differences were seen between strains from oral and nonoral sites. None of the antigens of B. melaninogenicus subsp. intermedius reacted with sera raised to several strains of oral or nonoral B. asaccharolyticus, nor did antigens prepared from the latter strains react with antisera to B. melaninogenicus subsp. intermedius. At least one common antigen was shared by strains of B. melaninogenicus subsp. intermedius and strains of B. melaninogenicus subsp. melaninogenicus; however, subspecies-specific antigens were also found. Antigens from and antisera to oral and nonoral strains of B. asaccharolyticus did not react with sera to and antigens from B. melaninogenicus subsp. melaninogenicus. Strains of B. asaccharolyticus isolated from the oral cavity were antigenically distinct from strains of B. asaccharolyticus obtained from nonoral sites and lesions. This lack of cross-reactivity between the oral and nonoral strains of B. asaccharolyticus together with recent findings of marked genetic differences between oral and nonoral strains of B. asaccharolyticus suggest that these groups of organisms may represent different species.

Antigens, Bacterial↗
PubMed1980

Actinobacillus actinomycetemcomitans in human periodontal disease: a cross-sectional microbiological investigation.

Actinobacillus actinomycetemcomitans is a facultative gram-negative bacterium which has been associated with severe oral and nonoral infections. This study examined its occurrence in the oral cavities of 10 normal juveniles, 11 normal adults, 10 juvenile periodontitis patients, and 12 adult periodontitis patients. Four deep periodontal pockets and two normal periodontal sites were sampled in the diseased patients, and six normal periodontal sites were sampled in the healthy individuals. In all subjects samples were obtained from the cheek, tongue, and saliva. Samples from a total of 172 normal periodontal sites, 83 deep periodontal pockets, 42 cheek mucosae, 42 tongue dorsa, and 42 salivas were examined. Isolation was performed by using a medium for selective isolation of A. actinomycetemcomitans (Trypticase soy agar [BBL Microbiology Systems] supplemented with 10% serum and 75 mug of bacitracin per ml). The carrier rates were 20% for normal juveniles, 36% for normal adults, 50% for adult periodontitis patients, and 90% for juvenile periodontitis patients. A. actinomycetemcomitans was on average recovered in about fivefold-higher numbers from infected deep periodontal pockets than from infected normal subgingival areas. Samples of periodontal pockets generally contained 100-fold-more cells of A. actinomycetemcomitans than did samples of the cheek, tongue, and saliva. A. actinomycetemcomitans is commonly isolated from patients with juvenile periodontitis, often isolated from patients with adult periodontitis, and occasionally isolated from normal juveniles and adults. Its primary oral ecological niche appears to be dental plaque and periodontal pockets.

Actinobacillus Infections↗
PubMed1980

Evaluation of Fluoretec-M for detection of oral strains of Bacteroides asaccharolyticus and Bacteroides melaninogenicus.

Fluoretec-M is a polyvalent conjugate used in direct fluorescent-antibody staining for identification of the Bacteroides asaccharolyticus-Bacteroides melaninogenicus group. The Fluoretec-M reagent detected all oral and nonoral test strains of B. melaninogaenicus subsp. intermedius, all test strains of B. melaninogenicus subsp. melaninogenicus, and the nonoral strains of B. asaccharolyticus. However, the Fluoretec-M polyvalent reagent and the monovalent conjugates which constitute Fluoretec-M did not detect the oral strains B. asaccharolyticus. The use of Fluoretec-M can therefore generate false-negative results in studies of specimens from oral cavity and from nonoral sites in which an infection with B. asacacharolyticus of oral origin may have taken place. It is suggested that antibodies reactive with the oral antigenic type of B. asaccharolyticus be included in the preparative procedure of the Fluoretec-M reagent.

Bacteroides↗
PubMed1980

Pathogenicity testing of Macaca arctoides subgingival plaque following chlorhexidine treatment.

POTENTIAL INFECTIVITY of subgingival plaque of Macaca arctoides in guinea pig leg muscle was examined before, during, and after chlorhexidine treatment. The regime of chlorhexidine administration did not appear to alter the monkey subgingival microflora markedly and had no demonstrable effects on the pathogenicity of the subgingival plaque. These data confirm previous suggestions that chlorhexidine essentially does not penetrate into the deeper part of periodontal pockets following a supragingival mode of administration.

Abscess↗
PubMed1979

A rapid, semi-automated procedure for the evaluation of leukocyte locomotion in the micropore filter assay.

A commerically available bacterial colony counter has been modified to allow rapid, accurate, semi-automated evaluation of cell numbers in the micropore filter assay for chemotaxis. The method is valuable for objective, rapid evaluation of cell counts at various levels through the filter, as well as counts on the distal surface of the filter. Coupled with a programmable calculator, this instrument had made feasible a new method of assessing random migration by the regression line analysis, which discriminates between migration rate and mass migration of cells. This combination of equipment may thus serve as a considerable time saving accessory to laboratories engaged in cell locomotion research, but also will allow more rigorous assessment of differences among specific populations of cells.

Analysis of Variance↗