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Biomedical subjects

J X Lin

Publications and source records attributed to J X Lin.

11 recordsLinked to original sources
PubMed1992

Effect of the vertical force component of Class II elastics on the anterior intrusive force of maxillary archwire.

Class II elastics are usually employed in the treatment of excessive overbite and overjet with the Begg technique. The effect of Class II elastics on bite opening and the extent of such an effect is uncertain. This article, based on measurements of 30 cases, illustrates that the effect of the vertical component of force from Class II elastics in reducing the intrusive force generated by the anchor bands in the upper archwire is less than previously believed. The position of the circles in the archwire for intermaxillary elastics has the greatest influence on the anterior intrusive force of the upper archwire. The direction of the Class II elastics and the length of the dental arch (a negative correlation) came second, while the force actually exerted by the elastics had the smallest influence. It is, therefore, suggested that the position of the intermaxillary elastic circles should be located according to the differing clinical objectives.

Dental Stress Analysis↗
PubMed1992

[Study of dento-maxillo-facial growth and development on anterior deep bite with linguoversion of upper incisors during permanent dentition].

By means of computer-X-ray cephalometric system to study the dento-maxillo-facial growth and development was performed in 65 patients of anterior deep bite with lingoversion of upper incisors. The patients were divided into two groups: (1) 35 cases aged 12-16 years and (2) 30 cases aged 17-26 years. The same number of the subjects with normal occlusion were used as control group. The findings were as follows: 1. Besides the dento-maxillo-facial growth and development was abnormal vertically, the posterior anterior discrepancy of the growth trend is also one of the main problems in this kind of malocclusion. 2. The growth of the alveolar bone was inhibited anteriorly by the upper incisors; 3. The deformed mandible has the growth trend to rotate forward and upward in Counterclock wise direction so that it is wise to treat of early.

Adolescent↗
PubMed1991

[Factor analysis of anterior deep bite malocclusions and its significance].

A series of 38 measurements was derived from lateral cephalometric radiographs of a large sample of 195 subjects including 130 patients with deep bite malocclusion and 65 control subjects with normal occlusion. These measurements were subjected to a factor analysis which resulted in a series of 8 factors extracted which accounted for 83.3% of the total variance. These factors in rank order of their percentage sample variability were as follows. Factor 1: vertical height; Factor 2: protrusion-retrusion of anterior teeth; Factor 3: protrusion of mid-face; Factor 4: horizontal position of posterior border of the jaws;Factor 5: protrusion of the chin; Factor 6: protrusion of lip; Factor 7: divergence of the face;Factor 8: inclination of upper Lip. The factor scores were further used in a multiple regression analysis in order to predict other cases. The data-reduction method involving a factor analysis would seem to have great significance of clinical application.

Adolescent↗
PubMed1990

Interleukin-6 induction by tumor necrosis factor and interleukin-1 in human fibroblasts involves activation of a nuclear factor binding to a kappa B-like sequence.

Using variable-length deletion constructs of the 5'-flanking region of the human interleukin-6 (IL-6) gene linked to the chloramphenicol acetyltransferase gene, we showed that the region from positions -109 to -50 mediated the bulk of the response to tumor necrosis factor (TNF) or interleukin-1 (IL-1), while it was less responsive to forskolin. DNA mobility shift assays and DNase I footprinting analysis identified a nuclear protein from TNF- or IL-1-treated fibroblasts that bound to a region comprising a kappa B-like element located between positions -72 and -63 on the IL-6 gene. On the basis of these and other experiments, we conclude that TNF and IL-1 apparently activate IL-6 gene expression by closely related mechanisms involving activation of a NF-kappa B-like factor, whereas the pathway of IL-6 induction by forskolin is, in part, different.

Base Sequence↗
PubMed1990

[The importance of variability in morphologic feature of upper central incisors in linguoversion anterior deep over bite].

190 subjects with linguoversioffl anterior deep over bite, labioversional anterior deep over bite, normal occlusion and anterior cross-bite were chosen for cephalometric analysis. The findings are that most of the upper central incisors in linguoversional anterior deep over bite exist crown-root angulation in a labiolingual direction. This may be one of the causing factors to induce and promote the anterior deep over bite. So that the crown-axis and root-axis of the upper central incisors should be traced separately in cephalometric analysis of linguoversional anterior deep over bite.

Adolescent↗
PubMed1988

Synthesis of interleukin 6 (interferon-beta 2/B cell stimulatory factor 2) in human fibroblasts is triggered by an increase in intracellular cyclic AMP.

Interleukin 6 (IL-6; also referred to as interferon-beta 2, 26-kDa protein, and B cell stimulatory factor 2) is a cytokine whose actions include a stimulation of immunoglobulin synthesis, enhancement of B cell growth, and modulation of acute phase protein synthesis by hepatocytes. Synthesis of IL-6 is stimulated by interleukin 1 (IL-1), tumor necrosis factor (TNF), or platelet-derived growth factor. We examined the role of the cyclic AMP (cAMP)-dependent signal transduction pathway in IL-6 gene expression. Several activators of adenylate cyclase, including prostaglandin E1, forskolin, and cholera toxin, as well as the phosphodiesterase inhibitor isobutylmethylxanthine and the cAMP analog dibutyryl cAMP, shared the ability to cause a dramatic and sustained increase in IL-6 mRNA levels in human FS-4 fibroblasts. Actinomycin D treatment abolished this enhancement. Treatments that increased intracellular cAMP also stimulated the secretion of the IL-6 protein in a biologically active form. Increased intracellular cAMP appears to enhance IL-6 gene expression by a protein kinase C-independent mechanism because down-regulation of protein kinase C by a chronic exposure of cells to a high dose of 12-O-tetradecanoylphorbol 13-acetate did not abolish the enhancement of IL-6 expression by treatments that increase cAMP. IL-1 and TNF too increased IL-6 mRNA levels by a protein kinase C-independent mechanism. Our results suggest a role for the cAMP-dependent pathway(s) in IL-6 gene activation by TNF and IL-1.

1-Methyl-3-isobutylxanthine↗