Biomedical subjects

H M Rogers

Publications and source records attributed to H M Rogers.

9 recordsLinked to original sources

PubMed1999

Endotoxin affinity for orthodontic brackets.

Endotoxin, cell envelope lipopolysaccharide produced by gram-negative bacteria can activate an immune response through a variety of pathways. In addition, it can stimulate bone resorption and reduce the periodontal tissue's healing capacity. Previous studies have documented the affinity of lipopolysaccharide for restorative materials. This study evaluated the affinity of lipopolysaccharide for commercially available orthodontic brackets. Stainless steel, ceramic, plastic, and "gold" brackets were exposed to 10 EU/mm2radiolabeled Porphyromonas gingivalis or Escherichia coli lipolpoysaccharide in water and incubated for 24 hours at 37 degrees C. Brackets were then transferred to fresh lipopolysaccharide-free water and incubated for 24 hours at 37 degrees C to evaluate elution. This elution transfer was continued up to 96 hours total incubation. Lipopolysaccharide adherence and elution levels were calculated after treatment, and elution solutions were evaluated through liquid scintillation spectrometry. Mean initial lipopolysaccharide adherence ranged from 2.42 +/- 0.26 EU/mm2(E. coli, plastic) to 6.75 +/- 0.34 EU/mm2 (P. gingivalis, stainless steel). P. gingivalis lipopolysaccharide adherence was significantly greater than E. coli lipopolysaccharide adherence for all bracket types. Moreover, for each lipopolysaccharide type, stainless steel brackets exhibited significantly greater lipopolysaccharide adherence. Regarding elution, only the P. gingivalis lipopolysaccharide-exposed ceramic and plastic brackets at 24 hours and the stainless steel and ceramic brackets at 48 hours eluted measurable lipopolysaccharide. Results from this study demonstrate that P. gingivalis and E. coli LPS exhibit a high affinity for orthodontic brackets. In vivo, this affinity could affect the concentration of LPS in the gingival sulcus, thereby contributing to inflammation in tissues adjacent to the brackets.

Analysis of Variance↗

PubMed1994

On the inheritance of intracranial aneurysms.

BACKGROUND AND PURPOSE: The familial occurrence of intracranial aneurysms suggests the presence of a genetically determined underlying arteriopathy. The pattern of inheritance in these families usually is not known. METHODS: A family with seven members with intracranial aneurysms is described and, from the literature before 1994, a total of 238 families with 560 affected members (56% female and 44% male) with intracranial aneurysms not associated with a known heritable disease are reviewed. A segregation analysis was performed on 73 of these families. RESULTS: Two members were affected in the great majority of families (79%); five or more members were reported in only eight families (3%). The most common affected kinship was among siblings. Angiographic screening in 12 families detected an intracranial aneurysm in 29% of 51 asymptomatic relatives. Segregation analysis revealed several patterns of inheritance that were consistent with the compiled pedigrees, but no single mendelian model was the overall best fitting, suggesting that genetic heterogeneity may be important. Twenty-two percent of siblings of male probands had an intracranial aneurysm compared with 9% of siblings of female probands (P = .003). CONCLUSIONS: Genetic heterogeneity may be important in the genetics of intracranial aneurysms. In families with intracranial aneurysms, siblings of an affected male proband may be at a higher risk of developing an aneurysm than siblings of an affected female proband. Screening for intracranial aneurysms in asymptomatic relatives should be considered in families with two or more affected members. In most families, the nature of the underlying arteriopathy remains obscure.

Adult↗

PubMed1992

Dentistry in Dohnavur, 1955-1992.

In October 1955 I arrived here in Dohnavur, India, as a young, reluctant dental missionary! My first hurdle was to learn the language--Tamil--said to be one of the most difficult languages in the world. For the first year I was given one hour 'off' language study to do dentistry. In that hour I began to see our large family, which then numbered about 900. In the second year, still in a room with only the dental chair and a foot engine for temporary use, I spent half the time in dentistry and continued to learn Tamil the rest of the time. The dental surgery was built, and the equipment that I had brought with me from UK had been installed, and on December 17, 1957, we had the dedication of the dental surgery and I had the joy of having my parents with me from the UK for that special day.

Dental Clinics↗

PubMed1986

Monitoring of chloroquine sensitivity of Plasmodium falciparum in Haiti, 1981-1983.

Between 1981 and 1983, in vivo and in vitro studies were conducted in Haiti to assess the responsiveness of Plasmodium falciparum to chloroquine. The standard tests successfully performed included 92 WHO standardized in vivo field tests and 160 in vitro tests (64 macrotests, 33 microtests, and 63 48-hr tests). No clearcut evidence of chloroquine resistance was detected. In 3 in vivo and 5 in vitro tests, a decreased susceptibility to the drug was suggested, but these isolated findings failed to be corroborated by parallel alternate tests. In addition, during the initial trial of an alternate monitoring system, 339 simplified 7-day in vivo tests were successfully performed, with no suggestion of resistance detected. This simplified 7-day in vivo test potentially represents an efficient low cost method for monitoring drug resistance in many developing countries.

Animals↗

PubMed1973