[ ABSTRACT] AIM:To investigate the role of chronic psychological stress on periodontitis and the effects of hy-perbaric oxygen ( HBO) on periodontitis with psychological stress in rats.METHODS:Male special pathogen-free Wistar rats (n=80) were randomly divided into 4 groups:(1)normal control group;(2)experimental periodontitis group:the pe-riodontitis model was induced by wrapping 3/0 silk ligature inoculated with Porphyromonas gingivalis around the left maxil-lary second molar of the rats; ( 3 ) psychological stress stimulation group; ( 4 ) periodontitis model with stress stimulation group.Psychological stress was removed at the 9th week after ligature, and 4 rats from each experimental group were ran-domly chosen for HBO treatment.The rats were sacrificed at the 2nd, 4th, 8th and 10th weeks after ligature.The levels of blood glucose, adrenocorticotropic hormone ( ACTH) , corticosterone and adrenaline were measured as the stress markers. The histological changes of periodontal tissues were observed under microscope with HE staining.RESULTS:The levels of blood glucose, ACTH, corticosterone and adrenaline in psychological stress stimulation group and periodontitis with stress group were significantly higher than those in control group and experimental periodontitis group at the 2nd and 4th weeks af-ter ligature (P<0.05).The levels of the stress markers were significantly lower than those in untreated groups in the 10th week after HBO (P<0.01).The sites of gingival attachment were normal in control group and psychological stress stimu-lation group.Periodontal pocket, and periodontal attachment loss ( AL) were observed in experimental periodontitis group. The tissue damage was much heavier in periodontitis model with stress stimulation group as the furcation of tooth was ex-posed and the tissue damage was observed on both sides of the adjacent teeth.No significant difference of AL between psy-chological stress stimulation group and normal control group during the experiment was observed.The AL in periodontal model with stress stimulating group was significantly higher than that in experimental periodontitis group at the 2nd, 4th and 8th weeks (P<0.01).The level of AL was attenuated at the 10th week after HBO (P<0.01).No difference of histologi-cal change in periodontal tissues was observed between control group and psychological stress stimulation group.Severer in-flammatory changes and alveolar bone destruction were observed in periodontitis with stress group than those in experimental periodontitis group.The levels of inflammation reduced at the 10th week after HBO.CONCLUSION:Stress stimulation is one of the inducing factors of periodontitis in rats, which aggravates periodontitis.HBO may represent a useful way in trea-ting psychological stress periodontitis.

Objective To investigate the surgical exposure of the subtemporal approach and explore clinical indications using a minimal-access.Methods Ten adult cadaveric heads fixed with formalin were used in this study.The holes with 3.0 cm × 2.5 cm of zygomatic arch vertically were operated on each head with subtemporal approach.During the anatomical procedures,measured the maximal exposure lengths of tentorial margin,posterior cerebral artery,and anterior border of brain stem,vertical distances between highest structure in the field of view and posterior clinoid process,the shortest distances form the zygomatic arch 1/3 to tentorial edge,sulcus lateralis mesencephali and anterior clinoid process; After tentorium of cerebellum was cut,measured the straight distance form the internal carotid artery to the optic nerve and form the posterior communicating artery to the tentorial edge.Results Oculomotor,trochlear nerve,tentorial edge,superior cerebllar artery.,P1-P2 segment of posterior cerebral artery,ventrolateral surface of mesencephalon and pon higher than root of trigeminal nerve,anterior and posterior clinoid process,posterior communicating artery and anterior choroidal artery,and superior portion of pituitary stalk could be observed via subtemporal approach using a minimal-access.Conclusion 1.The subtemporal approach using a minimal-access can protect the superficial temporal artery and the facial nerve branches especially in the process of the flap formation.It does little damage to the temporallis,reduces the invalid exposure of brain tissue,farthest lowers the damage to the scalp,skull and adjacent tissue ; 2.The subtemporal approach using a minimal-access can obtain the exposure rang.It can see the upper pons,petroclival region,tentorial notch area,ventrolateral brain stem.

Objective To test experimentally Fluoro-Jade B(FJB) stain method for detecting degeneration of neurons in the basal ganglia. Methods Kainic acid(KA)-lesion model by stereotaxical injection of KA into striatum of rats,MPTP-lesion model by injection of MPTP into intraperitoneal cavity of mice,as well as KA-lesion model of cultured striatal cells were firstly prepared.FJB stain dye was then used to visualize degeneration of neurons in above KA-or MPTP-lesion models. Results KA-or MPTP-induced degenerative neurons including cell bodies and processes could be clearly visualized by FJB stain dye.In the brain sections,FJB-positive stained degenerative neurons were numerously observed in the striatum of KA-lesion rats and the substantia nigra pars compacta of MPTP-treated mice,but not detected in the control animals.Moreover,degenerative neurons were also detected with FJB stain in cultured striatal neurons.Semi-quantitative analysis on percentage(?s) of FJB-positive neurons constituting total cultured striatal neurons in unit area showed that degenerative neurons of KA-lesion group (8.42?1.09)% was evidently more than that of controls (3.42?0.45)%,P