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Biomedical subjects

H V Jordan

Publications and source records attributed to H V Jordan.

At least 19 recordsLinked to original sources
PubMed1990

Association of the microbial flora of dental plaque and saliva with human root-surface caries.

Dental plaque was obtained from one or two sound root surfaces of subjects with different degrees of root-surface caries experience. From subjects with root-surface caries, plaque samples were also obtained from either one incipient or one more advanced lesion. Proportions of the total flora were determined for total streptococci and different streptococcal species, total and different Actinomyces species, and lactobacilli. A sample of saliva was obtained from about one-third of the subjects for determination of the concentrations of mutans streptococci and lactobacilli. The main observations were: (1) Subjects without root-surface caries or restorations (group I), as compared with subjects with root-surface caries with or without restorations (group II), were characterized by having a lower prevalence and proportion of mutans streptococci and a higher prevalence and proportion of A. naeslundii in plaque on sound root surfaces; (2) subjects in group I also tended to have a lower salivary concentration of mutans streptococci and lactobacilli than subjects in group II; (3) dental plaque on sound surfaces in group II subjects contained a lower proportion of mutans streptococci than plaque associated with incipient or advanced lesions; and (4) the prevalence and proportion of lactobacilli in plaque associated with sound as well as carious root surfaces were very low. The data reinforce findings from other studies and indicate that, as for coronal caries, the plaque and saliva populations of mutans streptococci specifically are correlated positively with the presence of root-surface caries.

Actinomyces↗
PubMed1987

A simplified diagnostic system for cultural detection and enumeration of Streptococcus mutans.

A simple dip-slide test (Cariescreen SM) based on MSB selective agar was devised for detection and quantitation of Streptococcus mutans in oral samples. For this test, a bacitracin tablet is dissolved in a vial containing buffered saline diluent. Paraffin-stimulated saliva is collected in this diluent vial. A dip slide which incorporates a modified MSB agar (minus bacitracin) is immersed briefly in the diluted saliva. After addition of a CO2-generating tablet, the screw-cap dip slide is closed tightly in the vial and incubated for two days at 37 degrees C and one day at room temperature. S. mutans populations in saliva are estimated by comparison with a colony density chart. Growth of reference strains of S. mutans was equivalent on Cariescreen SM dip slides and on MSB agar plates. Reference strains of Streptococcus sanguis, Streptococcus salivarius, Streptococcus mitis, and Streptococcus milleri did not grow on Cariescreen SM dip slides. Aliquots of saliva from 50 schoolchildren and 51 adults were tested by the dip-slide method and by conventional plating methods in MSB agar. Very good correlation (0.93) between the two methods was obtained. This simplified S. mutans detection system is suitable for use by clinical personnel in dental clinics or other non-laboratory settings for identification of subjects potentially at risk for caries.

Bacitracin↗
PubMed1986

Colonization of Syrian hamsters with streptomycin resistant Campylobacter jejuni.

A streptomycin resistant Campylobacter jejuni inoculated per os into two populations of Syrian hamsters (one endemically harboring C. jejuni, the other free of C. jejuni) established chronic colonization of the organism in both groups. Diet, steroid administration, age of hamsters or prior exposure to C. jejuni did not appreciably alter incidence of diarrhea or colonization of C. jejuni. The majority of hamsters sampled during the course of the experiment (1 to 22 weeks) shed streptomycin resistant C. jejuni in the feces. In four hamsters sampled at 14, 17, 19, and 22 weeks, post inoculation, streptomycin resistant C. jejuni were recovered in ileal, cecal, jejunal, duodenal and colonic contents (10(4) to 10(7) colony forming units/gram of intestinal content). The hamster appears to be a potentially useful model for the study of intestinal colonization of enteropathogenic C. jejuni. Hamsters shedding C. jejuni in their feces for extended periods of time should be considered a zoonotic threat to both pet owners and laboratory personnel.

Animals↗
PubMed1985

Infectivity and natural transmission of the bacterium Streptococcus mutans in monkeys (Macaca fascicularis) at different ages.

Oral inoculation of adolescent monkeys with laboratory strains of Streptococcus mutans resulted in only sporadic implantation. Oral colonization of all strains, except possibly one, was not enhanced by dietary sucrose compared with glucose nor by precleaning of accessible tooth surfaces. Infant animals were more susceptible to implantation by laboratory-maintained strains of Strep. mutans than adolescent or adult animals. This difference was magnified when in-vivo maintained Strep. mutans strains were used. Strep. mutans was readily acquired by uninfected adolescent animals from infected cage mates. Strep. mutans-free adolescent monkeys exhibited significant-salivary IgA and serum-IgG response to Strep. mutans antigen, possibly representing a cross-reaction to indigenous Streptococcus sanguis. Uninfected infant animals showed no salivary or serum response to Strep. mutans. There was no change in salivary IgA antibody to Strep. mutans in adolescent animals after implantation or in recipient animals after acquisition of Strep. mutans.

Age Factors↗
PubMed1985

Transmission of the oral bacterium Streptococcus mutans to young Macaca fascicularis monkeys from human nursery attendants.

Streptococcus mutans was detected in the mouths of 2 out of 7 infant monkeys that had been delivered by caesarian section and nursery-reared without contact with their mothers or other monkeys. Their human nursery attendants all harboured Strep. mutans biotype c (c serotype) as found in the monkeys. Bacteriocin studies also indicated similarity between the animal and human isolates. These findings suggest that the infant monkeys acquired Strep. mutans from the nursery personnel. Evidence for the reverse transmission of enterococci, from monkeys to man was also obtained.

Animals↗
PubMed1976

The determinants of pelvic brim morphology in the female.

There is a significant positive correlation between the brim index and the conjugate dimension (r = 0,66). The latter also shows a high degree of correlation with stature (r = 0,58). The inverse covariability between the transverse inlet diameter and the brim index is weak (r = -0,17). The larger brim areas and brim indices of taller women are due to their greater sagittal inlet measurements.

Adult↗
PubMed1976

Cariogenic flora: establishment, localization, and transmission.

The foregoing is a review of current information on various aspects of the development of the cariogenic flora and it illustrates some of the complexities involved. The multifactorial nature of dental caries makes it necessary to look at this disease in a special way. Etiologic forces represented by a complex bacterial flora and a variable dietary influence are in competition with resistance factors of the host, which include the immune system. This creates a situation where it is difficult to segregate individual aspects of the disease for study. One approach is to design study models that emphasize the factor under investigation in relation to other contributing factors. For example the currently used animal caries test models are deliberately exaggerated in terms of the cariogenic challenge applied. Very young animals are continuously exposed to a high sucrose diet and are infected with a high dosage of cariogenic organisms. The clinical counterpart of this model should use subjects with high caries activity, because it is reasonable to assume that etiologic factors are exaggerated in human populations where the disease is rampant. However, if the purpose is to study resistance factors such as immunity, it may be more profitable to investigate their influence in either animal or human models where the cariogenic challenge is reduced. This, in effect, proportionally increases the influence of a comparatively subtle factor such as immunity. Davies has made a similar point in relation to the influence of hereditary factors in dental caries. He states the belief that regions of low caries prevalence would be the most promising for epidemiological investigation of resistance factors. Investigations into the role of immunity in dental caries have not been too productive in the past. However, it now is possible to focus on selected target organisms and to apply recently acquired information about the immune system operating in the oral cavity. Detailed knowledge of the origins and development of the cariogenic flora and the mechanisms by which it is maintained in individuals and in populations should permit a rational attack on the problem.

Age Factors↗