Biomedical subjects

Jian-jun Chen

Publications and source records attributed to Jian-jun Chen.

6 recordsLinked to original sources

PubMed2006

A multi-center study of hemodynamic characteristics exhibited by children with unexplained syncope.

BACKGROUND: Syncope is common in children and adolescents, with 15% estimated to have had at least one syncopal episode by age 18. In recent years, an increasing number of children, especially girls at their school age, have developed unexplained syncope. The mechanism of an unexplained syncope exhibited by children is incompletely studied; the association between different hemodynamic patterns and clinical features is also not clear. The aim of the study was to investigate the hemodynamic patterns of children with unexplained syncope and to examine the clinical relevance. METHODS: Two hundred and eight children [87 boys, 121 girls, aged 3 - 19 years, mean (11.66 +/- 2.72) years] were selectively recruited from May 2000 to April 2006 when they presented syncope as their main complaint at the Multi-center Network for Childhood Syncope in Beijing, Hunan Province, Hubei Province, and Shanghai of China. All of the patients underwent head-up tilt tests; data were analyzed using SPSS version 10.0 for Windows. Continuous variables were expressed as the mean +/- standard deviation. Dichotomous variables were compared through a chi(2) test. A value of P < 0.05 (two sided) was regarded as statistically significant. RESULTS: The age distribution of children with syncope was approximately normal. Head-up tilt tests was positive in 155 children, and the incidence of positive response of the baseline head-up tilt test for diagnosing unexplained syncope was 50.48%. The sensitivity value and diagnostic value of sublingual nitroglycerin head-up tilt test were both 74.52%. The hemodynamic pattern was normal in 53 children. The 155 children, who were positive in head-up tilt tests, showed signs of postural orthostatic tachycardia syndrome (60, 28.8%), the vasoinhibitory pattern (72, 34.6%), the cardioinhibitory pattern (5, 2.4%), and the mixed pattern (18, 8.7%). The gender distribution between the two age groups (age < 12 years vs age > or = 12 years) was not different (P > 0.05). The distribution of hemodynamic patterns between the children of the two age groups (age < 12 years vs age > or = 12 years), and the children with different complaints (dizziness vs syncope) was significantly different (P < 0.05), while the distribution between the children of different sexes and different lasting time of syncope (< or = 5 minutes vs > 5 minutes) was not significantly different (P > 0.05). Different hemodynamic patterns were differentiated by differing syncope inducements, presymptoms, and complicated symptoms during and after syncope. CONCLUSION: The tested girls were more prone when compared with the boys to have unexplained syncope, and the peak age was around twelve years old. The incidence of positive response of head-up tilt tests was also relatively higher for the girls. The distribution of hemodynamic patterns for different ages was different. For children with unexplained syncope, we should use head-up tilttests to distinguish the hemodynamic patterns in order to adopt rational therapeutic measures.

Adolescent↗

PubMed2006

[Individual 3-D image prototyping models for orbital reconstruction].

OBJECTIVE: To fabricate a rapid prototyping (RP) 3-D image models for individual reconstruction of orbital bony loss. METHODS: The skull was placed on a helical CT scanner table and the Frankfort plane was perpendicular to the table. The CT data was obtained by a Aquilion (TOSHIBA, Japan) with 1 mm thickness section in spiral mode. By adjusting of CT threshold value and pixels in order to stack the segmental defects, we obtained an approximate 3-dimension visual model of the scanned skull using MedGraphics software. An orbital RP model based on the dataset of the 3-dimension visual model was fabricated by RP machine. Both 3-dimension visual model and RP model were measured against the skull with several anatomic landmarks to examine the accuracy of the models, and the errors were analysed. RESULTS: Integrity precision rapid RP models of the orbital region were reconstructed. The anterior orbital rim, middle orbital section and posterior orbital section were all fabricated. Optic foramen, superior orbital fissure, infraorbital foramen, inferior orbital fissure, lacrimal sac socket and naso-lacrimal duct were shown clearly. But some fine hole and slot, such as the anterior ethmoidal foramen, posterior ethmoidal foramen and zygomaticofrontal suture were not obviously seen. The mean difference between the 3-dimension visual model and the skull was 0.10 +/- 1.02mm. For the RP and dry skull, the mean difference was 0.22 +/- 1.04mm. There were no statistical differences between them. CONCLUSIONS: Integrity precision orbital RP models were fabricated which fulfilled the requirements of the individual reconstruction with bony orbital pathologic changes. The keys to fabricate the precision orbital RP models included a closer cooperation between the surgeon and engineer, thin CT slice in 1mm thick and an appropriated threshold value. Better results for the orbital deformities should be achieved for the contour of orbital region or eye function.

Humans↗

PubMed2006

[Establishing three-dimensional reconstruction and measuring system for complete denture occlusion].

PURPOSE: This study was designed to investigate the digital method of locating and reconstructing the occlusal relationship between the upper and lower full dentures. METHODS: The artificial teeth occlusal surfaces of ten complete dentures were scanned by non-contact laser scanner and were reconstructed by three-dimensional technique. With placements of 6 standard steel ball, the three-dimensional position relationship of upper and lower full dentures were studied and reconstructed in centric occlusal position. RESULTS: The three-dimensional reconstruction and measuring system of complete denture occlusion was preliminarily established in this study. CONCLUSIONS: This study focused on exploiting a new system to quantitatively reconstruct the occlusal relationship of complete denture in centric occlusion. And the study may set a methodological foundation of further three-dimensional research for complete denture occlusion.

Dental Occlusion↗

PubMed2005

[Association of clinical features with different hemodynamic patterns in head-up tilt test in children with unexplained syncope].

OBJECTIVE: To explore the different hemodynamic patterns during the course of head-up tilt tests in children with unexplained syncope and the association of clinical features with different hemodynamic patterns in head-up tilt test in children with unexplained syncope. METHODS: 100 pediatric patients with unexplained syncope, aged 11 +/- 2 (6-16), 36 male and 64 female, with the mean course of 10 +/- 16 months (2 d-5 y), underwent head-up tilt tests or head-up tilt tests potentiated with nitroglycerine under quiet circumstance. Blood pressure and heart rate were monitored simultaneously. According to their different hemodynamic patterns, they were divided into vasovagal response pattern, postural orthostatic tachycardia syndrome (POTS) response pattern, orthostatic hypotension (OH) response pattern and normal response pattern. The vasovagal response was divided into vasodepressor, cardioinhibitory and mixed patterns. The distribution and different clinical features of different response patterns in the unexplained syncope were also studied. RESULTS: Fifty (50%) of the 100 children with unexplained syncope displayed the hemodynamic pattern of vasovagal response, among which 31 (31%) displayed the pattern of vasodepressor response, 7 (7%) cardioinhibitory response, and 12 (12%) mixed response. Thirty-three patients (33%) displayed POTS response, 2 (2%) OH response, and 15 (15%) the normal hemodynamic response. Patterns of dysautonomic response and chronotropic incompetence were not observed in these children with unexplained syncope. The age of the children with normal response during HUT was 10 +/- 3 years, significantly younger than that of the children with vasovagal response and POTS response (12 +/- 2 and 12 +/- 2, both P < 0.01). There were no differences in sex ratio and duration of syncope among the vasovagal response, POTS and normal response. But the syncopal spells in the children with POTS response was less frequent and the baseline heart rate of the children with POTS response was 81 +/- 7, significantly faster than that of the children with vasovagal response and normal response (71 +/- 9 and 74 +/- 7, both P < 0.01). There was no significant difference in the baseline blood pressure among the children with vasovagal response, POTS and normal response. There were also no significant differences in the age, sex ratio, and duration of syncope, number of syncopal spells, baseline heart rate, and baseline blood pressure among the children with vasodepressor response, cardioinhibitory response and mixed response. CONCLUSION: There are different hemodynamic response patterns in head-up tilt testing in children with unexplained syncope, and there was some association between hemodynamic response patterns and their clinical features.

Adolescent↗

PubMed2005

[Research status of genodermatoses in China].

Among over 300 genodernatoses, causative genes have been identified in 170 monogenetic diseases, while gene mapping has been performed in over 100 monogenetic and polygenctic skin diseases. Researches in genodermatoses has rapidly advanced in China in recent ten years. The causative genes involved in multiple familial trichoepithelioma and primary erythermalgia have been found. Two independent genome-wide scans with DNA markers have been performed to detect genetic linkage related to psoriasis and vitiligo. In this review article, we summarize these most recent findings.

Erythromelalgia↗

PubMed2004

[Simultaneous determination of 4 anthraquinones in Kuhuang injection by RP-HPLC].

OBJECTIVE: To develop a new high-performance liquid chromatographic method for simultaneous quantitative determination of 4 anthraquinones in Kuhuang injection. METHOD: The chromatographic separation was performed on a Lichrospher C18 column (4.6 mm x 250 mm, 5 microm,), A linear gradient elution of A (CH3COOH: H2O = 1:100) and B (CH3COOH: H2O: CH3CN = 1:20:80) was used. The flow rate was 0.8 mL x min(-1) and column temperature was set at 35 degrees C. The UV detection wavelength was set at 254 nm. RESULT: The recoveries of rhein, emodin, chrysophanol and physcion were 98.9%, 100.5%, 102.5% and 99.0%, respectively. Their linear ranges were 0.0875-1.75 microg for rhein, 0.0825-1.65 microg for emodin, 0.159-3.17 microg for chrysophanol and 0.0525-1.05 microg for physcion, respectively. CONCLUSION: The method was accurate, repeatable and suitable to determine the contents of 4 anthraquinones in Kuhuang injection.

Anthraquinones↗