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Biomedical subjects

R J Fitzgerald

Publications and source records attributed to R J Fitzgerald.

At least 91 records · Page 5Linked to original sources
PubMed1982

Growth inhibition of oral streptococci in saliva by anionic proteins from two caries-free individuals.

Mixed saliva from two caries-free individuals possessed antimicrobial activity toward Streptococcus mutans and S. sanguis. This inhibitory activity was attributed to the presence of a group of four anionic proteins each of which strongly inhibited the growth of the oral streptococci in a saliva protein-based medium but not in a medium containing amino acids as a nitrogen source. These proteins, with isoelectric points of 4.70, 4.90, 4.98, and 5.05, respectively, neither reacted with antisera to immunoglobulin A, G, or M nor appeared to be functionally related to a number of salivary peroxidases, lactoferrin, or lysozyme. On this basis, they may represent a previously unreported group of growth-inhibitory antimicrobial factors occurring in the saliva of some individuals.

Adolescent↗
PubMed1981

Cariogenicity of human plaque lactobacilli in gnotobiotic rats.

Thirty-two strains of Lactobacilli, comprising eight species and obtained from human dental plaque or other sources, were tested for cariogenic potential in gnotobiotic Sprague-Dawley rats receiving modified cariogenic Diet 2000. Seventeen of these strains were moderately to highly cariogenic, and only one, a strain of Lactobacillus lactis, was scored as non-cariogenic. The molar fissures were the predominant site of caries attack. Primary lesions of the smooth surfaces were infrequently seen, although these surfaces were often secondarily involved by the extension of fissure lesions. . The preferential location of caries in the sheltered fissure sites was attributed to their inability to form adherent plaque deposits on the smooth surfaces of the teeth. Caries production by a strain of L. salivarius was equally severe on sucrose- or glucose-containing versions of Diet 2000, but glucose was less supportive of caries development than sucrose for a strain of L. fermentum. It is concluded that a wide variety of lactobacilli may be cariogenic under favorable environmental conditions.

Animals↗
PubMed1981

Utilization of hydroxyapatite adsorbable salivary proteins as growth substrates for plaque-forming oral streptococci.

Following treatment with hydroxyapatite, clarified mixed saliva from one donor source lost much of its growth-supportive activity for S. mutans VA-29R (type c). Growth of the organism in a basal medium containing proteins desorbed from HA with 0.067 M potassium phosphate buffer, pH 8.0, was accompanied by the disappearance of some of the proteins, including those with isoelectric points of 4.90, 5.72, and 6.00. These proteins are among those known to be specifically attacked by S. mutans. These findings suggest that some of the proteins selectively adsorbed from saliva with HA may serve as specific growth substrates for the plaque-forming oral streptococci.

Adsorption↗
PubMed1980

Characterization of two strains of cariogenic lactobacilli.

Two strains of lactobacilli that initiate dental caries in conventional animals were exained for their physiological and serological characteristics. The strain designated V CL-25 was identified as Lactobacillus fermentum and belonged to serological group F. The strain designated IV CL-37 was a Lactobacillus salivarius, but it could not be further identified as either of the known subspecies, nor did it belong to serological group G.

Child↗
PubMed1980

Cariogenicity of human oral lactobacilli in hamsters.

Of 50 strains of lactobacilli isolated from dental plaque of school children, two strains, provisionally identified as Lactobacillus salivarius, and one strain, provisionally identified as Lactobacillus fermentum, induced significant caries activity in conventional hamsters. Sucrose was a required dietary cariogenic substrate and could not be replaced with glucose or starch. In contrast to cariogenic strains of Streptococcus mutans the active lactobacilli did not form adherent sucrose-mediated plaques in vitro, did not form intracellular iodophilic polysaccharides and did not form detectable insoluble extracellular polyglucans.

Animals↗
PubMed1979

Differential utilization of proteins in saliva from caries-active and caries-free subjects as growth substrates by plaque-forming streptococci.

Mixed or parotid saliva from caries-active individuals consistently supported better growth of Streptococcus mutans (type c) than that from caries-free individuals. Electrophoretic studies revealed that certain proteins in caries-active salivas were susceptible to microbial attack, but similar proteins in caries-free salivas were refractory.

Adult↗
PubMed1978

Spontaneous perforation of bile ducts in neonates.

Three neonates with spontaneous perforation of the common bile duct have been described. All were treated by laparotomy in the seventh week, with attempted closure of the perforation and a simple biliary diversion by cholecyst-jejunostomy with jejunojejunostomy below it. They have done well and represent 100% salvage of our cases to date. One is now 12 years of age. As far as we are aware, this method of dealing with the condition has not been described before.

Biliary Fistula↗