Biomedical subjects

James K Hartsfield

Publications and source records attributed to James K Hartsfield.

5 recordsLinked to original sources

PubMed2005

Root resorption associated with orthodontic force in inbred mice: genetic contributions.

Root resorption (RR) is an unwanted sequela of orthodontic treatment. Despite rigorous investigation, no single factor or group of factors that directly causes RR has been identified. The purpose of this study was to examine the effect of the genotype on susceptibility or resistance to develop RR secondary to orthodontic force. Nine-week-old male mice from eight inbred strains were used and randomly distributed into control (C) or treatment (T) groups as follows: A/J (C = 9,T = 9), C57BL/6J (C = 7,T = 8), C3H/HeJ (C = 8,T = 6), BALB/cJ (C = 8,T = 6), 129P3/J (C = 6,T = 8), DBA/2J (C = 8,T = 9), SJL/J (C = 8,T = 10), and AKR/J (C = 9,T = 8). Each of the treated mice received an orthodontic appliance to tip the maxillary left first molar mesially for 9 days. Histological sections of the tooth were used to determine RR and tartrate resistant acid phosphatase (TRAP) activity. The Wilcoxon ranked-sum non-parametric test was used to evaluate differences between the groups. The results showed that the DBA/2J, BALB/cJ, and 129P3/J inbred mouse strains are highly susceptible to RR, whereas A/J, C57BL/6J and SJL/J mice are much more resistant. The variation in the severity of RR associated with orthodontic force among different inbred strains of mice when age, gender, food, housing, and orthodontic force magnitude/duration are controlled support the hypothesis that susceptibility or resistance to RR associated with orthodontic force is a genetically influenced trait.

Acid Phosphatase↗

PubMed2004

Comprehensive clinical evaluation as an outcome assessment for a graduate orthodontics program.

To supplement the American Board of Orthodontics (ABO) objective grading system (OGS) for posttreatment dental casts and panoramic radiographs, a comprehensive clinical assessment (CCA) method was developed to assess facial form, dental esthetics, vertical dimension, arch form, periodontium preservation, root resorption, and treatment efficiency. The sum of the CCA and the ABO OGS scores was defined as the clinical outcome. To determine a 3-year baseline for treatment outcomes in a graduate orthodontic program, the posttreatment records of 521 consecutive patients were evaluated. The mean ABO OGS score for the entire sample was 34.4 points: 32.4, 33.1, and 37.8 points for 1998, 1999, and 2000, respectively. The mean CCA score for the entire sample was 4.67 points: 2.96, 5.13, and 6.15 points for 1998, 1999, and 2000, respectively. Corresponding ABO OGS and CCA scores showed a progressive decrease in the quality of finished cases that was associated with a treatment time increase from 28.9 to 39.3 months. Overall, longer active treatment times resulted in a diminished clinical outcome, primarily due to "patient burn-out." Scoring of all finished cases is an effective means for determining clinical outcomes. However, the data suggest that, in initiating a clinical grading program, it is important to establish a multiyear baseline. Patients who are progressing well in treatment tend to be finished by the time the current class graduates, and the problem patients are transferred. Because long treatment times are associated with diminished clinical outcomes, it is often in the best interest of the uncooperative patient to terminate treatment rather than extend active mechanics in an attempt to achieve a better result.

Adolescent↗

PubMed2003

Genetic predisposition to external apical root resorption.

External apical root resorption (EARR) can be an undesirable sequela of orthodontic treatment. Previous studies have suggested that EARR has a substantial genetic component. Linkage and association were examined between polymorphisms of the interleukin IL-1 (IL-1A and IL-1B) genes and EARR in 35 white American families. Buccal swab cells were collected for DNA isolation and analysis. The EARR in the maxillary central incisors, the mandibular central incisors, and the mesial and distal roots of the mandibular first molar were analyzed separately and together by using both linkage and association methods of analysis. Highly significant (P =.0003) evidence of linkage disequilibrium of IL-1B polymorphism with the clinical manifestation of EARR was obtained. The analysis indicates that the IL-1B polymorphism accounts for 15% of the total variation of maxillary incisor EARR. Persons homozygous for the IL-1B allele 1 have a 5.6 fold (95% CI 1.9-21.2) increased risk of EARR greater than 2 mm as compared with those who are not homozygous for the IL-1 beta allele 1. Data indicate that allele 1 at the IL-1B gene, known to decrease the production of IL-1 cytokine in vivo, significantly increases the risk of EARR. These findings are consistent with an interpretation of EARR as a complex condition influenced by many factors, with the IL-1B gene contributing an important predisposition to this common problem. Defining genetic contributions to EARR is an important factor in understanding the contribution of environmental factors, such as habits and therapeutic biomechanics.

Alleles↗

PubMed2002

Refinement of the NHS locus on chromosome Xp22.13 and analysis of five candidate genes.

Nance-Horan syndrome (NHS) is an X-linked condition characterised by congenital cataracts, dental abnormalities, dysmorphic features, and mental retardation in some cases. Previous studies have mapped the disease gene to a 2 cM interval on Xp22.2 between DXS43 and DXS999. We report additional linkage data resulting from the analysis of eleven independent NHS families. A maximum lod score of 9.94 (theta=0.00) was obtained at the RS1 locus and a recombination with locus DXS1195 on the telomeric side was observed in two families, thus refining the location of the gene to an interval of around 1 Mb on Xp22.13. Direct sequencing or SSCP analysis of the coding exons of five genes (SCML1, SCML2, STK9, RS1 and PPEF1), considered as candidate genes on the basis of their location in the critical interval, failed to detect any mutation in 12 unrelated NHS patients, thus making it highly unlikely that these genes are implicated in NHS.

Cataract↗

PubMed2002

Polymorphisms of xenobiotic metabolizing genes in oropharyngeal carcinoma.

OBJECTIVE: The objective was to determine the prevalence of the polymorphisms of the microsomal epoxide hydrolase (Ephx1), glutathione S-transferase mu1 (GSTM ), theta1 (GSTT1), and pi1 (GSTP1) genes in patients with oropharyngeal carcinoma. STUDY DESIGN: Gene polymorphisms in 137 patients with oropharyngeal carcinoma were determined by polymerase chain reaction and restriction enzyme digestion for xenobiotic metabolizing enzymes that have been implicated in the carcinogenesis of tobacco-related neoplasias and compared with a population sample of 99 persons. RESULTS: At Ephx1 (microsomal epoxide hydrolase) codon 113, an overrepresentation of the greater activity genotype (Tyr/Tyr) was observed for male ever-smokers alone, both male and female ever-smokers, female never-smokers alone, and in both male and female never-smokers, compared with a control population sample. At codon 139, Ephx1 showed no differences. There was an overrepresentation of homozygosity for the GSTT1 (glutathione S-transferase theta1) null allele [but not for the GSTM1 (glutathione S-transferase mu1) null allele] in ever-smokers, when compared with controls. Polymorphisms at the GSTP1 (glutathione S-transferase pi1) locus did not show differences versus controls, although in the never-smoker cancer sample there was a higher prevalence of the B/B genotype compared with ever-smokers. CONCLUSION: The Ephx1 codon 113 Tyr/Tyr variant, as well as homozygosity for the GSTT1 null allele, is associated with oropharyngeal carcinogenesis.

Adult↗