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Biomedical subjects

G M Converse

Publications and source records attributed to G M Converse.

7 recordsLinked to original sources
PubMed2001

Comparison of wound healing using the CO2 laser at 10.6 microm and 9.55 microm.

OBJECTIVES/HYPOTHESIS: The wound healing characteristics of incisions made with the short pulsed CO2 laser tuned to 9.55 microm versus the traditional 10.6 microm were investigated. Previous studies have shown that at 9.55 microm, collagen is targeted more selectively than at 10.6 microm, which results in decreased acute thermal injury patterns. This study investigates the difference in wound healing over time between lasers and compares laser incisions with cold knife techniques. STUDY DESIGN: Randomized controlled trial using a porcine model. METHODS: Tissue from 10.6-microm and 9.55-microm incisions of 10 piglets was evaluated with histological analysis and tensiometry at 3, 7, 14, and 21 days postoperatively. A Bonferroni-Dunn corrected analysis of variance analysis at a 95% significance level was used to compare the effect of wavelength. RESULTS: The results demonstrate that although knife incisions are consistently stronger than laser incisions, the 9.55-microm CO2 laser incisions are no stronger than incisions made with the conventional 10.6-microm laser. Furthermore, histological analysis shows no difference in lateral thermal damage between lasers at 3, 7, 14, and 21 days postoperatively. The progression of collagen formation and inflammation does not differ over time. CONCLUSION: This study of wound healing using a porcine model demonstrates that the 9.55-microm CO2 laser does not demonstrate an improvement in wound healing over the traditional 10.6-microm CO2 laser. These results may be secondary to the common explosive vaporization mechanism produced by both lasers in the infrared spectrum.

Analysis of Variance↗
PubMed1981

Epidemiologic studies of Streptococcus pneumoniae in infants: antibody response to nasopharyngeal carriage of types 3, 19, and 23.

The relationship between nasopharyngeal carriage of Streptococcus pneumoniae types 3, 19, and 23 and the development of homotypic serum antibody was examined in 17 infants followed prospectively from birth. Serially drawn sera from these children and single serum samples from 18 normal adolescents were assayed for opsonizing antibody using reduction of nitroblue tetrazolium to measure phagocytosis of killed whole pneumococci. Selected sera were also tested for quantitative antibody level by a radioimmunoassay, which correlated quite well with the nitroblue tetrazolium assay. All but one of the adolescents had antibody to type 19, and all 18 had antibody to type 23. None of the 12 infants tested for antibody to type 19 pneumococci showed evidence of an antibody response. Two of 10 infants responded to type 23 pneumococci, as did two of three infants tested to type 3 pneumococci.

Antibodies, Bacterial↗
PubMed1980

Epidemiologic studies of Streptococcus pneumoniae in infants: acquisition, carriage, and infection during the first 24 months of life.

A natural history study of pneumococcal infection in 82 infants followed from birth is reported. Longitudinal carriage patterns were determined by serial throat and nasopharyngeal cultures. Seventy-nine of 82 infants carried one or more types during the study period. The first type was acquired by a mean age of six months, and the duration of carriage decreased with successive types carried. Acquisition of new types peaked in winter months, but carriage rates fluctuated throughout the year. Thirty-one pneumococcal infections were documented in 24 infants: 28 episodes of otitis media, two of bacteremia, and one of meningitis. Types causing disease were similar to commonly carried types (6, 14, 19 and 23). However, infection usually occurred within one month of acquisition of a new type and was seldom associated with prolonged carriage. In terms of exposure to new strains, 15% (31 of 196) of acquisitions resulted in disease.

Age Factors↗
PubMed1979

Serotypes of Streptococcus pneumoniae causing disease.

Serotypes of Streptococcus pneumoniae from 525 infected children were examined over a four-year period. Type distribution was similar among 84 cases of bacteremia and 30 cases of meningitis, with types 6, 14, and 18 accounting for half of the illnesses. In contrast, half of 396 episodes of otitis media were caused by three other types, 19, 23, and 3. Four of eight fatalities were due to type 6. Carrier strains isolated from children had a distribution of types similar to that of the otitis media collection. Adult patients had fewer of the types that caused disease in children. Most childhood infections (80%) occurred in children less than or equal to 24 months of age; no relationship between age and infecting serotype was noted. There were no seasonal trends in type distribution.

Child↗
PubMed1977

Epidemiological studies of Streptococcus pneumoniae in infants: methods of isolating pneumococci.

A prospective study of the natural history of pneumococcal infection, which involves serial culture studies in healthy infants from 6 weeks of age onward, is in progress in our laboratory. This report describes results of a comparison of several methods for the isolation and identification of Streptococcus pneumoniae from the nasopharynges and throats of these infants. Sheep blood agar, sheep blood agar with gentamicin sulfate (gentamicin agar), and mouse inoculation with 4-h broth cultures were used. Gentamicin agar proved superior to plain sheep blood agar as a solid culture medium, especially in enhancing the recovery of pneumococci from throat cultures. With gentamicin agar, similar carrier rates were found for both culture sites (nasopharynx and throat). In addition, gentamicin agar proved superior to mouse inoculation for the recovery of carrier strains from 131 nasopharyngeal culture samples processed by both methods. Sixty of 131 samples were positive for pneumococci, 25% of which would have been missed had mouse inoculation alone been used. In only three instances did we recover a strain by mouse inoculation that failed to grow on gentamicin agar; conversely, 15 strains were isolated on gentamicin agar but could not be recovered from mice. The latter observation might be explained by the fact that certain carrier strains may be relatively mouse avirulent. The use of blood agar containing gentamicin appears to offer a simple and inexpensive method for the recovery of S. pneumoniae and, in our opinion, provides an ideal method for the identification of pneumococcal carriers as well as for the recovery of these strains from clinical material such as sputum or ear exudates, where other and less fastidious organisms may also be present.

Agar↗