L X Yin | PubMed Health

PubMed2001

[The experimental study of the delayed replantation after cryopreservation of mature tooth in dogs].

OBJECTIVE: To study the conditions of healing of mature tooth in dogs after long cryopreservation followed by replantation. METHODS: The tooth was extracted after filling the root canals and then preserved for one week and three months respectively by Schwartz's method of cryopreservation of periodontal membrane. The specimens were took out eight weeks after replantation. It was demineralized in a 5% solution of formic acid,and then sectioned perpendicular to the long axes of tooth at a thickness of 5microm. The tooth were sectioned in step-serial sections at 500 microm intervals. The sections were stained with hematoxylin-eosin and followed by evaluation according to Andreasen. RESULTS: The percentage of healing of periodontal membrane (PHPM) of the group of cryopreservation for one week was 64.53%. It was lower than the PHPM of the group of immediate replantation (85%), but the difference demonstrated no significance (P>0.05). The PHPM of the group of cryopreservation for three months was 50.3%. It was lower than the PHPM of the group of immediate replantation significantly (P<0.05). CONCLUSION: The human's periodontal membrane may be cryopreserved longly and heals after the replantation of tooth as the human's tissues of corneas, skin, islets, et al may be done. The alveolar cavities to be newly made affect the healing of periodontal membrane in some degree.

English Abstract↗

PubMed1999

Ventricular excitation maps using tissue Doppler acceleration imaging: potential clinical application.

OBJECTIVES: The purpose of this study is to validate the use of tissue Doppler acceleration imaging (TDAI) for evaluation of the onset of ventricular contraction in humans. BACKGROUND: Tissue Doppler acceleration imaging can display the distribution, direction and value of ventricular acceleration responses to myocardial contraction and electrical excitation. METHODS: Twenty normal volunteers underwent TDAI testing to determine the normal onset of ventricular acceleration. Two patients with paroxysmal supraventricular tachycardia and 30 patients with permanent pacemakers underwent introduction of esophageal and right ventricular pacing electrodes, respectively, and were studied to visualize the onset of pacer-induced ventricular acceleration. Eight patients with dual atrioventricular (AV) node and 20 patients with Wolff-Parkinson-White (WPW) syndrome underwent TDAI testing to localize the abnormal onset of ventricular acceleration, and the results were compared with those of intracardiac electrophysiology (ICEP) tests. RESULTS: The normal onset and the onset of dual AV node were localized at the upper interventricular septum (IVS) under the right coronary cusp within 25 ms before the beginning of the R wave in the electrocardiogram (ECG). In all patients in the pacing group, the location and timing of the onset conformed to the positions and timing of electrodes (100%). In patients with WPW syndrome, abnormal onset was localized to portions of the ventricular wall other than the upper IVS at the delta wave or within 25 ms after the delta wave in the ECG. The agreement was 90% (18 of 20) between the abnormal onset and the position of the accessory pathways determined by ICEP testing. CONCLUSIONS: These results suggest that TDAI is a useful noninvasive method that frequently is successful in visualizing the intramural site of origin of ventricular mechanical contraction.

Adolescent↗