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Biomedical subjects

C E Miller

Publications and source records attributed to C E Miller.

At least 91 records · Page 5Linked to original sources
PubMed1977

The viscoelastic nature of chorioamniotic membranes.

This study establishes the viscoelastic nature of the human chorioamniotic membrane. Membrane tissue taken from term pregnancies was placed in a state of biaxial stress consistent with the condition in which membranes rupture in normal healthy patients. The phenomena of creep, stress relaxation, elastic recovery, and time-dependent load deformation relations were demonstrated. The experiments needed to produce these phenomena are described. The results are graphically reported. The experiments were performed using samples of fetal membranes and compared to gum rubber which is a known elastic material. From the results, one can conclude that fetal membranes are viscoelastic. The flow freely under applied stress, and they have elastic and viscous properties which are time dependent.

Amnion↗
PubMed1975

Competitive effects of intestinal microflora on Vibrio cholerae in gnotobiotic mice.

The coexistence of Vibrio cholerae and several intestinal bacteria was determined in gnotobiotic mice. The bacteria tested included a Bacteroides sp, Clostridium difficile, Clostridium perfringens type A, 2 separate isolates of Escherichia coli, 2 different Lactobacilli, 2 separate isolates of Proteus mirabilis, Pseudomonas maltophilia, and Streptococcus faecalis. Each species of bacteria became established and was recovered repeatedly from the stools during the studies. No single strain or species was found that would eliminate V cholerae from these mice within 2 wk. Not until a combination of E coli, P mirabilis, and S faecalis was present in the mice did V cholerae disappear from the stools in 14 da.

Animals↗
PubMed1973

Determination of endotoxicity in bacterial vaccines.

Endotoxicity of bacterial vaccines was quantitated in mice by using actinomycin D as potentiating agent. The results were compared with those obtained by the mouse weight gain test. The lethality of Escherichia coli lipopolysaccharide was increased 2,140 times when 12.5 mug of actinomycin D was used. The mean lethal dose values of heated and unheated pertussis vaccines were similar in the actinomycin D enhancement assay, but the unheated vaccine was significantly more toxic in the mouse weight gain test. Acetone-inactivated typhoid vaccine was slightly less toxic than the heat-phenol-inactivated vaccine in both the actinomycin D enhancement assay and mouse weight gain test. Endotoxicity of experimental vaccines prepared by extraction of Pseudomonas aeruginosa strains was high as compared with E. coli lipopolysaccharide. The BALB/c mice were about four times more susceptible than the random bred NIH strain mice. The results indicate that the actinomycin D enhancement assay had the advantages of being more sensitive and probably more specific.

Acetone↗
PubMed1972

Immunological conversion of Vibrio chorlerae in gnotobiotic mice.

Cholera vibrios grow readily in the intestines of gnotobiotic mice and change their antigenic structure in response to immunological pressures. These changes were progressive, with the rough form persisting as the apparent end point in the mice. Inoculation of the rough form into fresh gnotobiotic mice resulted in the recovery of smooth forms. An untypable rough strain of Vibrio cholerae isolated from a chronic carrier in Calcutta in 1967 was passed serially in gnotobiotic mice. Smooth strains of V. cholerae were recovered from the feces after selective treatment with complement and antiserum against a rough strain. They were confirmed as O group I cholera vibrios belonging to the eltor biotype. The ability of these strains to produce diarrheal fluid in infant rabbits and to increase capillary permeability in rabbit skin was markedly increased over that of the original human isolate. This demonstrates that rough avirulent forms of V. cholerae from human carriers can undergo antigenic changes and concurrently increase in virulence when placed in an appropriate environment. The many inapparent cholera infections in endemic areas may provide a mechanism by which V. cholerae changes its serotype away from the immunological pressures in the population.

Animals↗
PubMed1969

Progressive changes of Vibrio serotypes in germ-free mice infected with Vibrio cholerae.

Germ-free mice inoculated with Vibrio cholerae became colonized with vibrios throughout the gastrointestinal tract, but they did not become ill. High vibrio concentrations in the feces were observed throughout the 3 months of observation in spite of the presence of serum antibody. Reciprocal conversions of both Inaba and Ogawa serotypes occurred regularly after inoculation and could be correlated temporally with the appearance of serum-agglutinating antibody. Both of these smooth serotype were later progressively replaced by rough vibrios. Rough to smooth serotype reversions were also found in mice inoculated with a rough vibrio strain. Studies employing immunosuppression and selective vaccination suggested that such serotypic changes were a result of the selective effect of antibody within the intestinal lumen.

Agglutination↗