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Biomedical subjects

J Caton

Publications and source records attributed to J Caton.

At least 19 recordsLinked to original sources
PubMed1992

Biological and measurement issues critical to design of gingivitis trials.

Chronic plaque-induced gingivitis is usually of little consequence, thus the concern about prevention and treatment must stem from the belief that preexisting gingivitis is necessary for periodontitis to develop. When clinical signs of gingivitis are present, an inflammatory infiltrate can be found upon histological evaluation. When clinical signs are absent, however, significant inflammation may still be present within the gingival tissues. Therefore, multiple clinical evaluations should be made, with special attention given to the visually inaccessible midinterdental area. The "gold standard" for evaluation of gingivitis is histological evaluation and other measurements should be evaluated against this standard. The significance of clinical severity measurements of gingivitis is not well-understood relative to onset of periodontitis; therefore, it is suggested that consideration be given to gingival evaluations based on the presence or absence of clinical signs of inflammation. Furthermore, equivalency and superiority of antigingivitis agents or devices should be predicated, at least in part, on their ability to prevent the onset of periodontitis.

Clinical Trials as Topic↗
PubMed1992

Guided tissue regeneration in interproximal defects in the monkey.

The potential for guided tissue regeneration was evaluated in one-walled interproximal sites in Macaca fascicularis. Histologic differences were evaluated at 1 and 3 months. Within the experimental (barrier) group, 100% of the root surfaces with potential for regeneration were covered with new cementum, whereas the control specimens had 20% or less new cementum. The amount of regeneration was determined by the position of the barrier membrane; the more coronal the barrier, the greater the regeneration. Observations indicated that the optimal time for barrier removal is between 1 and 3 months.

Animals↗
PubMed1990

Periodontal disease activity: a critical assessment.

Review of investigations using longitudinal probing and radiographic assessments indicate that the prevalence, magnitude, rate, and temporal patterns of periodontal destruction as well as the ability of clinical and laboratory tests to detect and predict loss of clinical attachment need further investigation. These unresolved issues are discussed and their impact on the practice of periodontics is examined.

Humans↗
PubMed1990

[Idiopathic high patella in adolescents. Apropos of 61 surgical cases].

The patellar height was measured according to the index of Caton and Deschamps. The normal index equals 1, the patella considered as being high with an index of 1.2 or greater. The authors reviewed 50 patients presenting with such an anomaly in patellar height to verify whether this patella alta said to be idiopathic was simply a radiographic sign or represented a true anatomic and clinical entity. 61 knees were hence operated on between 1963 and 1988, 50% of which had a lowering of the tibial tuberosity. In 8 cases, the lowering was performed secondarily, after a failure of the first operation to correct the anomaly. The mean pre-operative index of patellar height was 1.34 and the trochlea appeared indisputably dysplastic in 50 of the 61 cases. The mean age at the time of surgery was 17 years. Medial translation of the tibial tuberosity averaged 9.5 mm and the lowering 7 mm allowing a normalization of the patellar index. 76.8% of patients had a perfect post-operative stability, evaluated as a score of 8 or 9 on the ARPEGE scale. At the completion of this study it appeared that patella alta is rarely an isolated finding and is most often part of a regional patello-femoral dysplasia. Its existence, when responsible for a functional problem, must absolutely be taken into account and treated to obtain a satisfactory result.

Adolescent↗
PubMed1989

Effects of personal oral hygiene and subgingival scaling on bleeding interdental gingiva.

The aim of this study was to determine the effects of personal oral hygiene and subgingival scaling on bleeding interdental gingiva. The Eastman Interdental Bleeding Index (EIBI) was used to clinically evaluate interdental gingival status. Forty-seven bleeding interdental sites in 47 patients were divided into three groups. Sites in Group I bled on stimulation with wooden interdental cleaners. Groups II and III initially bled but were converted to nonbleeding with oral hygiene alone or oral hygiene combined with subgingival scaling, respectively. Interdental gingival biopsies were obtained and subjected to morphometric analysis to compare the three groups. The findings from this study indicated that: (A) personal oral hygiene reduced the magnitude and extent of the interdental inflammatory lesion; (B) subgingival scaling plus oral hygiene decreased the interdental inflammatory lesion to a greater extent than oral hygiene alone; (C) significant repair of the interdental lesion occurred within four weeks; and (D) the EIBI was an effective method for monitoring the effects of therapy directed towards resolution of the interdental inflammatory lesion.

Adult↗
PubMed1989

[Method of measuring the height of the patella].

The author describes a technique for evaluation of the height of the patella: it compares the distance between the lower border of the articular surface of the patella and the antero-superior border of the tibia with the length of the patellar articular cartilage.

Anthropometry↗
PubMed1988

Cell populations associated with conversion from bleeding to nonbleeding gingiva.

The purpose of this study was to observe changes in cell populations of the interdental gingival tissue, which accompanied the conversion of a bleeding to a nonbleeding state induced by scaling and improved oral hygiene. Fifteen bleeding and 18 stopped-bleeding interproximal gingival biopsies were obtained from 33 patients and processed for light microscopic evaluation. The morphometric analysis of eight connective tissue components revealed that the percentage volume density of all inflammatory cells decreased, and the percentage of fibroblasts and collagen increased, when the gingiva changed from a bleeding to a nonbleeding state. Furthermore, the inflammatory cell infiltrate in bleeding and stopped-bleeding specimens was dominated by mononuclear cells of the lymphocyte/macrophage/monocyte group, while plasma cells and polymorphonuclear leukocytes comprised only a small fraction of the inflammatory cells present. Significant repair of gingival connective tissue had occurred in the stopped-bleeding specimens.

Adult↗
PubMed1988

Associations between bleeding and visual signs of interdental gingival inflammation.

Interdental gingival tissues are designated inflamed on the basis of their color and bleeding after stimulation. Gingival bleeding was previously shown in histological studies to indicate the presence of inflammatory lesions. The present study was undertaken to determine associations between bleeding and visual signs of interdental gingival inflammation. Each interdental site in 82 males, aged 18 to 30, was evaluated for the presence or absence of visual signs of inflammation. The interdental sites on one side of the mouth were evaluated for bleeding tendency using the Papilla Bleeding Index (PBI), while the other half was evaluated using the Eastman Interdental Bleeding Index (EIBI). The percentage of inflamed areas detected with the EIBI and visual method was similar and significantly higher than with the PBI. When the visually noninflamed sites were examined, 38.5% of these areas bled, indicating that interdental inflammatory lesions existed in the absence of visual signs of inflammation. Of the sites that bled but were visually noninflamed, 33.1% were detected using the PBI, while 66.9% were detected using the EIBI. The Eastman Interdental Bleeding Index was a more reliable clinical indicator for detecting interdental inflammatory lesions than the Papilla Bleeding Index.

Adolescent↗
PubMed1988

Effect of personal oral hygiene on bleeding interdental gingiva. Histologic changes.

A previous study demonstrated that the combination of subgingival scaling and improved oral hygiene resulted in a reduction of clinical and histological signs of interdental gingival inflammation, changes that were associated with a cessation of interdental gingival bleeding. The present study compared, histologically, the interdental tissues of bleeding sites with sites that initially bled but had been converted to nonbleeding by an oral hygiene program alone. Morphometric analysis of interdental gingiva demonstrated that conversion from bleeding to nonbleeding was associated with a significant reduction in the inflamed connective tissue component. This study showed that an oral hygiene program consisting of toothbrushing and interdental cleaning could significantly reduce interdental inflammation, and that bleeding determinations monitored the effects of this therapy.

Adult↗
PubMed1987

Sequence analysis of the Alcaligenes eutrophus chromosomally encoded ribulose bisphosphate carboxylase large and small subunit genes and their gene products.

The nucleotide sequence of the chromosomally encoded ribulose bisphosphate carboxylase/oxygenase (RuBPCase) large (rbcL) and small (rbcS) subunit genes of the hydrogen bacterium Alcaligenes eutrophus ATCC 17707 was determined. We found that the two coding regions are separated by a 47-base-pair intergenic region, and both genes are preceded by plausible ribosome-binding sites. Cotranscription of the rbcL and rbcS genes has been demonstrated previously. The rbcL and rbcS genes encode polypeptides of 487 and 135 amino acids, respectively. Both genes exhibited similar codon usage which was highly biased and different from that of other organisms. The N-terminal amino acid sequence of both subunit proteins was determined by Edman degradation. No processing of the rbcS protein was detected, while the rbcL protein underwent a posttranslational loss of formylmethionyl. The A. eutrophus rbcL and rbcS proteins exhibited 56.8 to 58.3% and 35.6 to 38.5% amino acid sequence homology, respectively, with the corresponding proteins from cyanobacteria, eucaryotic algae, and plants. The A. eutrophus and Rhodospirillum rubrum rbcL proteins were only about 32% homologous. The N- and C-terminal sequences of both the rbcL and the rbcS proteins were among the most divergent regions. Known or proposed active site residues in other rbcL proteins, including Lys, His, Arg, and Asp residues, were conserved in the A. eutrophus enzyme. The A. eutrophus rbcS protein, like those of cyanobacteria, lacks a 12-residue internal sequence that is found in plant RuBPCase. Comparison of hydropathy profiles and secondary structure predictions by the method described by Chou and Fasman (P. Y. Chou and G. D. Fasman, Adv. Enzymol. 47:45-148, 1978) revealed striking similarities between A. eutrophus RuBPCase and other hexadecameric enzymes. This suggests that folding of the polypeptide chains is similar. The observed sequence homologies were consistent with the notion that both the rbcL and rbcS genes of the chemoautotroph A. eutrophus and the thus far characterized rbc genes of photosynthetic organisms have a common origin. This suggests that both subunit genes have a very ancient origin. The role of quaternary structure as a determinant of the rate of accepted amino acid substitution was examined. It is proposed that the sequence of the dimeric R. rubrum RuBPCase may be less conserved because there are fewer structural constraints for this RuBPCase than there are for hexadecameric enzymes.

Alcaligenes↗
PubMed1986

[Congenital superior radioulnar synostoses. A study of 43 cases].

Superior radioulnar synostosis is a rare abnormality which frequently gives rise to functional disability. Its pattern of inheritance is uncertain. We have studied 29 children, 18 boys and 11 girls, who had a total of 43 such synostoses. Twenty children had significant functional disability. Fourteen required operation, 10 undergoing a Judet's osteotomy and 4 osteotomy of the lower end of the radius. The dominant hand was placed in the position of function, and the other in 30-40 degrees of supination. The osteotomies were secured by pins and supported in a plaster splint. Use of the forearm and hand was improved in all cases. Operation is best carried out between the ages of 4 and 10, and a useful functional improvement can be expected.

Age Factors↗
PubMed1986

Interproximal gingival inflammation related to the conversion of a bleeding to a nonbleeding state.

Elimination of gingival bleeding has been related to a reduction in inflammation; however, histologic data are not available to support this association. The purpose of this study was to characterize the histology of interproximal gingiva that was converted from a bleeding to a nonbleeding state. An interproximal gingival biopsy was obtained from each of 32 patients, 15 of whom bled upon stimulation with a soft wooden interdental cleaner. The remaining 17 biopsies were obtained from sites which initially bled, but were converted to nonbleeding by scaling and interproximal plaque control. Specimens were processed for light microscopic evaluation and subjected to a morphometric analysis for various tissue components. Data from bleeding and "stopped bleeding" specimens were compared using analysis of covariance. The results indicated that "stopped bleeding" specimens had significantly less inflamed connective tissue. It was concluded that the conversion of a bleeding to a nonbleeding state corresponds with a histological reduction in the magnitude of the interproximal inflammatory lesion and provides a rationale, therefore, for the use of bleeding to monitor the effects of therapeutic methods.

Adult↗