The Effect of Functional Mandibular Shift on the Muscle Spindle Systems in Head-Neck Muscles and the Related Neurotransmitter Histamine.

The aim of this study is to explore the effects of abnormal occlusion and functional recovery caused by functional mandible deviation on the head and neck muscles and muscle spindle sensory-motor system by electrophysiological response and endogenous monoamine neurotransmitters' distribution in the nucleus of the spinal tract. Seven-week-old male Wistar rats were randomly divided into 7 groups: normal control group, 2W experimental control group, 2W functional mandible deviation group, 2W functional mandible deviation recovery group, 4W experimental control group, 4W functional mandible deviation group, 4W functional mandible deviation recovery group. Chewing muscles, digastric muscle, splenius, and trapezius muscle spindles electrophysiological response activities at the opening and closing state were recorded. And then the chewing muscles, digastric, splenius, trapezius, and neck trigeminal nucleus were taken for histidine decarboxylase (HDC) detection by high performance liquid chromatography (HPLC), immunofluorescence, and reverse-transcription polymerase chain reaction (RT-PCR). Histamine receptor proteins in the neck nucleus of the spinal tract were also examined by immunofluorescence and RT-PCR. Electromyography activity of chewing muscles, digastric, and splenius muscle was significantly asymmetric; the abnormal muscle electromyography activity was mainly detected at the ipsilateral side. After functional mandibular deviation, muscle sensitivity on the ipsilateral sides of the chewing muscle and splenius decreased, muscle excitement weakened, modulation depth decreased, and the muscle spindle afferent impulses of excitation transmission speed slowed down. Changes for digastric muscle electrical activity were contrary. The functions recovered at different extents after removing the deflector. However, trapezius in all the experimental groups and recovery groups exhibited bilateral symmetry electrophysiological responses, and no significant difference compared with the control group. After functional mandibular deviation, HDC protein and messenger ribonucleic acid (mRNA) levels on the ipsilateral sides of the chewing muscle and splenius increased significantly. HDC level changes for digastric muscle were contrary. After the removal of the mandibular position deflector, HDC protein and mRNA levels decreased on the ipsilateral sides of the chewing muscle and splenius while they increased in the digastric muscle. The difference of histamine decarboxylase content in the bilateral trapezius in each experimental group was small. After functional mandibular deviation, the temporomandibular joint mechanical receptors not only caused the fusimotor fiber hypoallergenic fatigue slow response on the ipsilateral sides of splenius, but also increased the injury neurotransmitter histamine release. The authors' results further support the opinion that the temporomandibular joint receptors may be involved in the mechanical theory of the head and neck muscles nervous system regulation.

[Study of occlusal force on female open bite patients with temporomandibular disorders].

OBJECTIVE: To investigate the effect of occlusal force on the etiology of open bite patients who suffer from temporomandibular disorders (TMD). METHODS: One hundred and two women patients with open bite were divided into TMD (+) group and TMD (-) group according to patients with or without TMD. Occlusal force, occlusal contact areas, occlusal average pressure and occlusal center were evaluated with pressure sensitive sheets. The results were analyzed by SPSS 11.0 statistic software. RESULTS: Occlusal force and occlusal contact areas in TMD (+) group were significantly lower than that in TMD (-) group. Occlusal average pressure and occlusal center had no significance between two groups. CONCLUSION: The results indicate that the decrease of occlusal force and occlusal contact areas may have some relationships with TMD in open bite patients.

[Seasonal rhythms of parathyroid hormone-related protein (PTHrP) expression in growing rats after functional mandibular protrusion].

OBJECTIVE: To study parathyroid hormone-related protein (PTHrP) expression during forward mandibular positioning and compare it with the expression during natural growth in different seasons. METHODS: Sixty-four SD rats were randomly divided into experimental and control groups. Each group were randomly divided into four groups according to seasons. Immunohistochemical (IHC) methods were used to test the protein expression of PTHrP. Macroscopic and microscopic approach were applied to analyze the results. RESULTS: PTHrP expressed in mandibular condylar cartilage (MCC), the expression was accelerated and enhanced when the mandible was positioned forward. Furthermore, there was a seasonal rhythm in the protein expression of PTHrP in both experimental and control groups. The protein expression in spring group rose more than other groups. CONCLUSION: The functional appliance therapy can enhance the protein expression of PTHrP. The enhancement has a seasonal rhythm, which indicates that for the functional treatment better results can be achieved in spring.

[Surgical treatment of 2465 primary hepatolithiasis cases].

OBJECTIVE: To summarize the experience of surgical treatment of primary hepatolithiasis. METHODS: To analyze the clinical data, operation choice, postoperative complications of 2465 cases of primary hepatolithiasis retrospectively. RESULTS: Of the patients, 2034 received external drainage (82.5%) and 431 received internal drainage (17.5%) and 586 were performed adjunctive partial hepatectomy (23.8%). The postoperative complications were found in 211 cases (8.6%) and 17 cases (0.7%) died after the operation. One thousand seven hundred and sixty-seven cases (71.7%) have been followed up for 2 to 25 years, among them therapeutic effect of 1518 cases (85.9%) was excellent or good, 315 cases (17.8%) had residual stone and 115 cases (6.5%) recurred. CONCLUSIONS: It could decrease the incidence rate of complications, residual stone and recurrence in the patients with hepatolithiasis after surgical therapy to pinpoint the situs of the lithiasis and biliary stricture and managed properly before the surgery.