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Biomedical subjects

M C Roberts

Publications and source records attributed to M C Roberts.

At least 199 records · Page 11Linked to original sources
PubMed1986

Dissemination of the tetM tetracycline resistance determinant to Ureaplasma urealyticum.

Ureaplasma urealyticum is an organism considered susceptible to tetracycline. Ten tetracycline-resistant (Tcr) clinical isolates and Tcr serotype 9 were examined. All contained DNA sequences homologous to the streptococcal determinant tetM. They differed from each other on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, Southern blots, and immunoblots and appeared to represent different strains.

DNA, Bacterial↗
PubMed1986

High-level tetracycline resistance in Neisseria gonorrhoeae is result of acquisition of streptococcal tetM determinant.

Recently, strains of Neisseria gonorrhoeae have been isolated which are highly resistant to tetracycline (MICs of 16 to 64 micrograms/ml). This resistance was due to the acquisition of the resistance determinant tetM, a transposon-borne determinant initially found in the genus Streptococcus and more recently in Mycoplasma hominis, Ureaplasma urealyticum, and Gardnerella vaginalis. In N. gonorrhoeae, the tetM determinant was located on a 25.2-megadalton plasmid. This plasmid arose from the insertion of tetM into the 24.5-megadalton gonococcal conjugative plasmid. The tetM determinant could be transferred to suitable recipient strains of N. gonorrhoeae by both genetic transformation and conjugation.

Conjugation, Genetic↗
PubMed1986

Tetracycline resistance and tetM in pathogenic urogenital bacteria.

Clinical isolates of Gardnerella vaginalis, Streptococcus agalactiae, Bacteroides spp., and Mobiluncus spp. were screened for resistance to tetracycline and for the presence of the streptococcal tetM determinant. The S. agalactiae and G. vaginalis strains contained DNA sequences homologous to the tetM determinant, while strains of the other two genera did not.

Bacteria↗
PubMed1986

Comparative physiology of the mammalian colon and suggestions for animal models of human disorders.

The large intestine is absent from the digestive tract of some mammals and shows a considerable degree of gross structural variation among the other species. The cecum serves as the major site for digesta retention and microbial fermentation in lagomorphs, most rodents, and many herbivorous marsupials, but the proximal colon appears to serve this purpose in most other mammals. The VFA end-products of microbial fermentation play an important role in the normal secretory and absorptive processes of the colon. Among those species that have received the most extensive study, the pig appears to have a colon most similar to that of humans in its gross structural and absorptive characteristics.

Animals↗
PubMed1985

Comparison of gram stain, DNA probe, and culture for the identification of species of Mobiluncus in female genital specimens.

The detection of species of Mobiluncus in female genital specimens by DNA probe (with whole-chromosomal bacterial DNA), culture, and gram stain were compared by using specimens obtained from hospital patients, college students, and women attending a sexually transmitted disease clinic. Culture purification and speciation required an average of 37 days to complete, whereas the DNA-probe assay required five days. Gram stain was also rapid but did not allow speciation. There was 100% correlation between species identification by DNA probe and by conventional biochemical tests. Gram stain alone detected 90% of the samples that were positive by any method, whereas culture detected 77%-83% and DNA probe detected 52%-83%.

Bacteria, Anaerobic↗
PubMed1985

Tetracycline-resistant Mycoplasma hominis strains contain streptococcal tetM sequences.

Clinical isolates of Mycoplasma hominis resistant to high levels of tetracycline contained DNA sequences homologous to the streptococcal tetracycline determinant, tetM. In contrast, none of the susceptible M. hominis isolates tested carried this determinant. This is the first description of tetM in an unrelated genus and suggests the spread of tetM from Streptococcus spp. to Mycoplasma spp.

DNA Restriction Enzymes↗
PubMed1985

Molecular characterization of chloramphenicol-resistant Haemophilus parainfluenzae and Haemophilus ducreyi.

We examined chloramphenicol-resistant Haemophilus parainfluenzae and Haemophilus ducreyi strains isolated in various parts of the world. The antibiotic resistance determinants were located on conjugative plasmids in H. ducreyi, but were chromosomally located in H. parainfluenzae. Both species produced chloramphenicol acetyltransferases (CATs) that were sensitive to 5,5'-dithiobis(2-nitrobenzoic acid) like the enteric type II and Haemophilus influenzae CAT enzymes, but differed from these enzymes in elution patterns and subunit molecular weight. Southern blot analysis showed the H. parainfluenzae and H. ducreyi CAT genes were molecularly related to the enteric type II class as well as the H. influenzae CAT. Heterogeneity of the physiochemical properties of the CATs was observed; however, the data suggested that all three Haemophilus spp. have a common ancestral source for the CATs.

Acetyltransferases↗
PubMed1985

Antigenic distinctiveness of Mobiluncus curtisii and Mobiluncus mulieris.

A total of 26 Mobiluncus strains (17 M. curtisii and 9 M. mulieris strains) were compared serologically by double immunodiffusion and immunoblotting against antisera prepared against representative isolates of each species. All strains from the same species were strongly reactive with homologous antisera but generally weakly reactive with antisera to the heterologous Mobiluncus spp. The antisera did not react with strains of the unrelated genera Campylobacter, Succinivibrio, Wolinella, Actinomyces, Anaerobiospirillum, and Anaerovibrio.

Antigens, Bacterial↗
PubMed1985

Marital interactions and the duration of alcoholic husbands' sobriety.

Recent studies of the family interactions of alcoholics have suggested that the alcoholic's general drinking adjustment may influence marital interactions. The present investigation examined the marital interactions of 30 male alcoholics who had maintained continuous sobriety for various lengths of time ranging from a few days to over 7 years. It was predicted that longer periods of sobriety would be associated with less conflict and fewer struggles for control between husbands and wives. The findings supported the hypothesis, in that the duration of the husbands' sobriety was significantly negatively correlated with the number of statements of disagreement emitted by husbands and wives. Also, there were trends for duration of sobriety to be negatively associated with the frequencies of question-asking and aggressive behaviors by husbands, and positively associated with the amount of talk time by husbands. Contrasts of 11 high sobriety couples (duration of sobriety: 2 years or longer) and 11 low sobriety couples (duration of sobriety: less than 4 months) revealed that high sobriety husbands asked fewer questions, stated fewer disagreements, and emitted fewer aggressive behaviors than husbands in the low sobriety group. In addition, high sobriety husbands displayed a trend toward more active talk time, and their wives showed a trend toward asking fewer questions than their low sobriety counterparts. The results suggest that marital functioning is superior in couples with longer periods of sobriety. The need for examining possible causal links in this relationship is emphasized.

Adult↗
PubMed1984

Human serum bactericidal activity against Haemophilus influenzae type b.

We examined bactericidal and opsonizing activity of pooled adult 'immune' serum against Haemophilus influenzae type b with and without the addition of phagocytes. Four type b strains from cerebrospinal fluid (CSF) and three such strains from the nasopharynx (NP) of healthy children were examined. Duplicate reaction mixtures contained organisms in exponential (E) or stationary phase (S) of growth, serum, a complement source (human agammaglobulinaemic serum), and culture medium (bactericidal assay); separate assays contained the above components and polymorphonuclear leucocytes (opsonization system). A decrease in bacterial density of greater than or equal to 1 log10 unit was considered significant. All four S-CSF strains, three of four E-CSF strains and one of three S-NP strains were sensitive to the bactericidal activity of pooled serum. The other E-CSF strain, two S-NP strains and all three E-NP strains were resistant to the bactericidal activity of pooled serum. Two of three E-NP strains were opsonized by pooled serum; the other strains resistant to the bactericidal activity of pooled serum were also resistant to opsonization. Bactericidal and opsonizing activity of serum from an immunized adult was greater than or equal to that of pooled serum against each strain. Assuming normal adults are immune to invasive H. influenzae type b infection, an experimental test reflecting this immunity is the bactericidal activity against CSF isolates tested in stationary phase. We conclude that protection against invasive disease due to H. influenzae type b appears more complex than the presence of bactericidal and opsonizing activity in serum.

Adult↗
PubMed1984

Selective media for the quantitation of bacteria in cystic fibrosis sputum.

We used selective media together with aerobic and anaerobic incubation for the quantitation of common pathogens in liquefied sputum from children with cystic fibrosis. The accuracy of the technique was verified by reconstruction studies in which laboratory strains with antibiotic-resistance markers were added to sputum from cystic fibrosis patients. Comparison of the numbers of bacteria found on quantitative culture of clinical specimens with the "predominant" organism found on routine culture yielded a poor correlation. When Pseudomonas aeruginosa was the most prevalent on routine culture, it was present in the highest numbers on quantitative culture (mean count = 10(8) cfu/g). However, large numbers of Haemophilus influenzae (mean count = 10(7) cfu/g), Staphylococcus aureus (mean count = 2 X 10(6) cfu/g), and streptococci (mean count = 2 X 10(6) cfu/g) were also present in these cultures. When S. aureus was the predominant organism, H. influenzae and P. aeruginosa were also present in similar numbers (c. 10(7) cfu/g). When H. influenzae was the predominant species on routine culture, the mean count was 7 X 10(6) cfu/g and P. aeruginosa was often completely absent. We conclude that the selective technique permits reliable enumeration of sputum bacteria, and offers a more accurate assessment of the microbial flora of sputum in cystic fibrosis than does simple plating of unhomogenised sputum.

Agar↗
PubMed1984

Preventing death and injury in childhood: a synthesis of child safety seat efforts.

Virtually all children are at risk for injury and death as passengers in moving vehicles. Between 70% to 90% of the injury and death could be reduced or prevented if children were restrained in safety seats. However, studies show that only a minority of children are properly protected. Numerous efforts have been made to increase the number of children riding in car safety seats. This article reviews and synthesizes the various attempts to motivate safety seat usage by examining the literature on (1) informational and educational programs; (2) safety seat loaner programs; (3) state laws requiring seat usage; (4) behavioral improvement emphasis programs; (5) reward-based programs; and (6) passive prevention approaches through airbags. No one approach appears to be the solution to the complex problem of motivating the preventive behavior of acquiring and consistently using safety seats. Recommendations are forwarded for: (1) developing and determining the best techniques for which settings through comparative research; (2) utilizing a developmental perspective in identifying when and what interventions are needed; and (3) implementing creative and comprehensive programs in communities.

Accidents, Traffic↗
PubMed1984

A preliminary evaluation of hospital preparation for nonpatient children: primary prevention in a "let's pretend hospital".

This study evaluated the effectiveness of an innovative program about hospitalization presented to nonpatient children on a community-wide basis. The "Let's Pretend Hospital" (LPH) is an experiential and informational program wherein a mock hospital is set up for children to visit. The present study compared the self-reported medical fears and amount of medical knowledge for two groups of children--one that went through the LPH program and one that did not. The results provide preliminary evidence of LPH effectiveness in that children who participated in the program reported fewer medical fears and greater medical knowledge than children who did not participate. The potential benefits of this innovative program are demonstrated.

Alabama↗