Biomechanical evaluation of various rigid internal fixation modalities for condylar-base-associated multiple mandibular fractures: A finite element analysis.

Condylar-base-associated multiple mandibular fractures are more prevalent than single ones. Direct trauma to mandibular symphysis, body or angle are prone to induce indirect condylar fracture. However, little is known about the effects of various rigid internal fixation modalities in condylar base for relevant multiple mandibular fractures, especially when we are confused in the selection of operative approach. Within the finite element analysis, straight-titanium-plate implanting positions in condylar base contained posterolateral zone (I), anterolateral zone (II), and intermediate zone (III). Von Mises stress (SS) in devices and bone and mandibular displacement (DT) were solved, while maximum values (SSmax and DTmax) were documented. For rigid internal fixation in condylar-base-and-symphysis fractures, I + II modality exhibited least SSmax in screws and cortical bone and least DTmax, I + III modality exhibited least SSmax in plates. For rigid internal fixation in condylar-base-and-contralateral-body fractures, I + III modality exhibited least SSmax in screws and cortical bone, I + II modality exhibited least SSmax in plates and least DTmax. For rigid internal fixation in condylar-base-and-contralateral-angle fractures, I + III modality exhibited least DTmax. The findings suggest that either I + II or I + III modality is a valid guaranty for rigid internal fixation of condylar base fractures concomitant with symphysis, contralateral body or angle fractures.

Rapid Eye Movement Sleep Deprivation Enhances Adenosine Receptor Activation and the CREB1/YAP1/c-Myc Axis to Alleviate Depressive-like Behaviors in Rats.

As neuromodulators, adenosine and its receptors are mediators of sleep-wake regulation. A putative correlation between CREB1 and depression has been predicted in our bioinformatics analyses, and its expression was also predicted to be upregulated in response to sleep deprivation. Therefore, this study aims to elaborate the A1 and A2A adenosine receptors and CREB1-associated mechanism underlying the antidepressant effect of rapid eye movement sleep deprivation (REMSD) in rats with chronic unpredictable mild stress (CUMS)-induced depressive-like behaviors. The modeled rats were injected with adenosine A1 receptor antagonist DPCPX or adenosine A2A receptor antagonist ZM241385 to assess the role of adenosine receptors in depression. In addition, ectopic expression and depletion experiments of CREB1 and YAP1 were also conducted in vivo and in vitro. It was found that REMSD alleviated depressive-like behaviors in CUMS rats, as shown by increased spontaneous activity, sucrose consumption and percentage, and shortened escape latency and immobility duration. Meanwhile, A1 or A2A adenosine receptor antagonists negated the antidepressant effect of REMSD. REMSD enhanced adenosine receptor activation and promoted the phosphorylation of CREB1, thus increasing the expression of CREB1. In addition, the overexpression of CREB1 activated the YAP1/c-Myc axis and consequently alleviated depressive-like behaviors. Collectively, our results provide new mechanistic insights for an understanding of the antidepressant effect of REMSD, which is associated with the activation of adenosine receptors and the CREB1/YAP1/c-Myc axis.

Insomnia symptoms are associated with metabolic syndrome in patients with severe psychiatric disorders.

OBJECTIVE: To examine the relationship between insomnia symptoms and metabolic syndrome in patients with severe psychiatric disorders. METHODS: We conducted a cross-sectional study including 272 inpatients (mean age: 34.06 ± 11.52 years, 67.3% males) with severe psychiatric disorders consecutively admitted in Shantou University Mental Health Center Inpatient Department. All patients underwent a psychiatric evaluation. Insomnia symptoms were assessed by the Pittsburgh Sleep Quality Index (PSQI) and defined present if PSQI>7. The diagnosis of metabolic syndrome was defined using the new International Diabetes Federation definition based on clinical and laboratory evaluation. RESULTS: Among the 272 patients, 94 (34.6%) presented insomnia symptoms. Overall, patients with insomnia symptoms had significantly higher percentage of metabolic syndrome (23.4% vs. 12.4%, p = 0.019) and hypertriglyceridemia (30.9% vs. 19.1%, p = 0.029), and marginally significantly higher levels of fasting insulin (58.75 ± 37.22 pmol/L vs. 51.72 ± 34.09 pmol/L, p = 0.050), homeostasis model assessment of insulin resistance (1.83 ± 1.31 vs. 1.62 ± 1.25, p = 0.055) and percentage of insulin resistance (55.3% vs. 44.4%, p = 0.086) compared to those without insomnia symptoms. Multiple logistic regressions showed that patients with insomnia symptoms had significantly higher odds for metabolic syndrome [odds ratio (OR) = 2.99, 95% confidence interval (CI) = 1.25-7.14], central obesity (OR = 3.02, 95% CI = 1.18-7.76), hypertriglyceridemia (OR = 2.46, 95% CI = 1.28-4.76) and marginally significantly higher odds for insulin resistance (OR = 1.68, 95% CI = 0.93-3.02) after controlling for potential confounders. CONCLUSIONS: Within severely mentally ill patients, insomnia symptoms are associated with metabolic syndrome and insulin resistance. It appears that insomnia symptoms are independent clinical indicators of underlying metabolic syndrome in patients with severe psychiatric disorders.

Sleep duration and metabolic syndrome: An updated systematic review and meta-analysis.

We examined the association between self-reported sleep duration and metabolic syndrome (MetS). Data were collected from 36 cross-sectional and 9 longitudinal studies with a total of 164,799 MetS subjects and 430,895 controls. Odds ratios (ORs) for prevalent MetS and risk ratios (RRs) for incident MetS were calculated through meta-analyses of adjusted data from individual studies. Short sleep duration was significantly associated with increased prevalent MetS (OR = 1.11, 95% CI = 1.05-1.18) and incident MetS (RR = 1.28, 95% CI = 1.07-1.53) in cross-sectional and longitudinal studies, respectively. Furthermore, long sleep duration was significantly associated with increased prevalent MetS in cross-sectional studies (OR = 1.14, 95% CI = 1.05-1.23), but not incident MetS (RR = 1.16, 95% CI = 0.95-1.41) in longitudinal studies. Interestingly, the association between long sleep and prevalent MetS was found in sleep duration defined by 24-h sleep (including naps) rather than nighttime sleep. Our findings suggest 1) a "U-shape" relationship between sleep duration and MetS in cross-sectional studies and 2) association between short sleep duration, but not long sleep duration with incident MetS. Future studies should shed light on the underlying mechanisms related to the association between sleep duration and MetS and examine if normalizing sleep duration reduces MetS risk in the general population.

Saliva cortisol, melatonin levels and circadian rhythm alterations in Chinese primary school children with dyslexia.

Cortisol is the main end product of hypothalamic-pituitary-adrenal gland (HPA axis), and melatonin (MT) has a regulating effect on HPA axis, and both are closely related to individual behavior and cognitive function. We aimed to evaluate cortisol and MT roles on children dyslexia in this study.A total of 72 dyslexic children and 72 controls were recruited in this study. Saliva samples were collected in the morning, afternoon, and night, respectively. The levels of saliva cortisol and MT were measured by enzyme-linked immunosorbent assay method. Differences of cortisol and MT levels between dyslexic and normal children were compared, and the variation trend was also analyzed by dynamic monitoring in 3 time points.The levels of salivary cortisol and MT in children with dyslexia were all lower than those in normal children whether in the morning (7:30-8:30 AM ), at afternoon (15:30-16:30 PM ) or at night (21:30-22:30 PM ) (all P < .001). Compared with normal children, the circadian rhythm variations of salivary cortisol and MT in dyslexic children disappeared and became disordered. The salivary cortisol and MT levels in children with dyslexia were declined throughout the day; and the circadian rhythm was disordered or disappeared.The results suggest that cortisol and MT levels and their circadian rhythm may affect children dyslexia, but the mechanisms need further exploration.

Involvement of family environmental, behavioral, and social functional factors in children with attention-deficit/hyperactivity disorder.

BACKGROUND: The objective of this study was to investigate relationships among family environmental characteristics, behavior problems, and social function impairments in children with ADHD. METHODS: Among children from four primary schools in Shantou city of China, 132 who were diagnosed with ADHD were selected and 138 typically developing children were recruited from the same schools. These children were evaluated using the self-designed questionnaire, FES-CV, CPRS, CTRS, and WFIRS-P for familial environment, behavioral problems, and social function impairment measures. In addition, children's behavioral problems and functional impairments were evaluated using self-established field behavior observation method. Logistic regression model was used to estimate ORs and 95% CIs for ADHD risk with family environmental factors. RESULTS: In the unconditional logistic model, ADHD risk in children was increased with parents' worse educational level, occupational status, and emotional stability with trend. Children with ADHD had lower scores on most subscales of FES-CV (P<0.01) but higher scores on Conflict subscale (P<0.001). Children with ADHD showed impairments on all the six WFIRS-P subscales tests (all P<0.001), and higher scores on the CPRS and CTRS scale subscales representing behavioral symptoms (all P<0.001 except Somatic Complaints), and more behavioral problems and functional impairments. CONCLUSION: Compared with typically developing children, children with ADHD had worse family environment. Family characteristics especially parents' emotional unstability, lower education levels, and worse occupation status may increase ADHD risk in children. In addition, the behavioral problems and social functional impairments may interact with adverse family environmental factors in children with ADHD. Therefore, early interventions with focus onto the compromising factors can be useful for improving the social-behavioral functions of children with ADHD.

Platelet serotonin and serotonin transporter as peripheral surrogates in depression and anxiety patients.

Previous studies suggested that serotonergic neurons and platelets share similarities in serotonin (5-HT) uptake by serotonin transporter (SERT), storage, metabolism and release mechanisms, indicating that platelets may be used as a reliable peripheral surrogate to measure central SERT activity in neuropsychiatric research. In this study, platelet 5-HT content and 5-HT uptake capacity of SERT in depression and anxiety patients were measured by ELISA and flow cytometry with IDT307 at baseline and after serotonin reuptake inhibitors (SSRIs) treatment for 4 weeks. Healthy persons matched with age and gender were used as reference. The clinical presentations of the patients were assessed with Hamilton Depression (HAMD) and Anxiety Rating Scales (HAMA) at the same time points. Compared to healthy subjects, anxiety and depression patients showed higher levels of platelet 5-HT and IDT307 fluorescence intensity, but the values were comparable between the patient groups. SSRIs administration for 4 weeks significantly decreased scores of HAMD (29 vs 14) and HAMA (22 vs 14) in depression and anxiety patients, respectively; while it decreased platelet 5-HT content, but did not change the IDT307 fluorescence intensity of platelets. After incubation with fluoxetine in vitro, the IDT307 fluorescence intensity of isolated platelets from both healthy subjects and patients decreased in a dose-dependent manner. These results provide further evidence supporting the employment of platelet 5-HT content and SERT as peripheral surrogates in depression and anxiety patients, and are of help in understanding the several weeks' delay from the initiation of antidepressant medication to their full therapeutic effects in the patients.

Attention-deficit hyperactivity disorder in elementary school students in Shantou, China: prevalence, subtypes, and influencing factors.

Attention-deficit hyperactivity disorder (ADHD) is a frequent childhood-onset psychiatric condition and categorized into three subtypes of predominantly inattentive (ADHD-I), hyperactive impulsive (ADHD-H), and combined (ADHD-C). The prevalence and subtypes of ADHD vary considerably. The primary aim of this study was to provide a prevalence estimate of ADHD in elementary school students living in Shantou, a district of China, and in addition to examine the influence of informants, age, and gender on the prevalence. A total of 3,497 students aged 7-12 years were enrolled by random and stratified sampling. In stage I, teachers and parents of all participating students in randomly selected schools were asked to complete Chinese versions of the Conners' 10-item scale. In stage II, students with high scores (>15) were interviewed by a psychiatrist for a diagnosis with or without ADHD. Parents rated many more students with high scores than teachers did in stage I. The prevalence of ADHD determined by Diagnostic and Statistical Manual of Mental Disorders, fifth edition (DSM-5) was 5.91% (5.27%-6.55%), which is comparable to the rates reported in previous studies with Chinese children. This hits the low border of the ADHD prevalence range from 5.9 to 7.1% worldwide, and is lower than that of Chinese children living in Hong Kong, suggesting an important influence of Chinese culture on the diagnosis of ADHD. The constituent ratios of ADHD-I, ADHD-C, and ADHD-H subtypes were 67.43, 24.57, and 8.00%, respectively. The rate of ADHD-H decreased with age, whereas that of ADHD-I remained at the highest levels in all age groups, suggesting that symptoms in the inattention domain are the most persistent and refractory.

Main Effects of Diagnoses, Brain Regions, and their Interaction Effects for Cerebral Metabolites in Bipolar and Unipolar Depressive Disorders.

Previous studies suggested patients with bipolar depressive disorder (BDd) or unipolar depressive disorder (UDd) have cerebral metabolites abnormalities. These abnormalities may stem from multiple sub-regions of gray matter in brain regions. Thirteen BDd patients, 20 UDd patients and 20 healthy controls (HC) were enrolled to investigate these abnormalities. Absolute concentrations of 5 cerebral metabolites (glutamate-glutamine (Glx), N-acetylaspartate (NAA), choline (Cho), myo-inositol (mI), creatine (Cr), parietal cortex (PC)) were measured from 4 subregions (the medial frontal cortex (mPFC), anterior cingulate cortex (ACC), posterior cingulate cortex (PCC), and parietal cortex (PC)) of gray matter. Main and interaction effects of cerebral metabolites across subregions of gray matter were evaluated. For example, the Glx was significantly higher in BDd compared with UDd, and so on. As the interaction analyses showed, some interaction effects existed. The concentrations of BDds' Glx, Cho, Cr in the ACC and HCs' mI and Cr in the PC were higher than that of other interaction effects. In addition, the concentrations of BDds' Glx and Cr in the PC and HCs' mI in the ACC were statistically significant lower than that of other interaction effects. These findings point to region-related abnormalities of cerebral metabolites across subjects with BDd and UDd.

Differential neurometabolite alterations in brains of medication-free individuals with bipolar disorder and those with unipolar depression: a two-dimensional proton magnetic resonance spectroscopy study.

OBJECTIVES: Bipolar disorder (BD) is a mental disorder characterized by periods of elevated mood and depression. Many individuals with BD are initially misdiagnosed and treated for unipolar depression (UD). In this study, we report direct comparisons between medication-free individuals with BD and those with UD in terms of the neurometabolites in the anterior cingulate cortex (ACC), medial prefrontal cortex (mPFC), parietal cortex (PC), and posterior cingulate cortex (PCC) of the brain. METHODS: Participants included medication-free patients with BD or UD, and matched healthy controls. All patients were in the depressive state and had similar symptoms. All subjects were subjected to a multi-voxel proton magnetic resonance spectroscopy procedure with a 3.0 T GE Signa MR scanner. After post-processing, the absolute concentrations of glycerophosphocholine + phosphocholine (GPC + PC), phosphocreatine + creatine (PCr + Cr), Glx (glutamate + glutamine), myo-inositol (MI), and N-acetyl aspartate (NAA) from the above brain regions were compared across the three groups. RESULTS: Patients with BD showed significantly higher levels of Glx in their ACC, lower GPC + PC, PCr + Cr, MI, and NAA in their PC, and lower NAA in their mPFC, compared to healthy controls; patients with UD presented significantly lower levels of GPC + PC, PCr + Cr, and NAA in their PCC, and lower Glx in their mPFC. All analyzed brain metabolites, except Glx, were significantly lower in the PC of patients with BD, whereas levels of GPC + PC, PCr + Cr, and NAA were significantly reduced in the PCC of patients with UD. CONCLUSIONS: These results add to the evidence of brain metabolite differences in brains of patients with UD and BD which may be of help in differentiating these two mood disorders.

Derivation and growth characteristics of dental pulp stem cells from patients of different ages.

The dental pulp contains a relatively low number of stem cells; however, it is considered to be a promising source of stem cells for use in regenerative therapy. To date, it has remained elusive whether there are certain differences in the dental pulp stem cells (DPSCs) from donors of different ages. In the present study, DPSC lines were derived using teeth from children, adolescents, adults and aged donors. The derivation efficiency, the proliferative and apoptotic rate, cell marker expression and the differentiation capacity were investigated and compared among these DPSC lines. The derivation efficacy was decreased with increasing donor age. Although a large part of cell surface markers was expressed in all DPSC lines, the expression of CD29 was downregulated in the DPSCs from aged teeth. In addition, the doubling time of DPSCs from aged teeth was prolonged and the number of apoptotic cells was increased with the propagation. These DPSCs were able to differentiate into a neuronal linage, which positively expressed the neuron-specific class III beta-tubulin and microtubule­associated protein 2, as well as into an osteogenic lineage, which positively expressed CD45; however, these DPSCs from aged teeth were completely or partially deprived of differentiation capacity. By contrast, DPSCs from younger teeth displayed significantly higher vitality and a higher potential for use in dental regenerative medicine.

Biomechanical evaluation of maxillary Lefort Ι fracture with bioabsorbable osteosynthesis internal fixation.

The aim of this study was to apply biomechanical analysis model to evaluate the effects of bioabsorbable internal fixation devices on maxillary Lefort Ι fracture. CT scan technology and the finite element software (ansys) were used to establish three-dimensional finite element models of five resorbable internal fixation devices in maxillary Lefort Ι fractures. We used the model to calculate the stress of the upper jaw and internal fixation. We further analyzed the stability of fixation under four occlusions. The fixation using two bioabsorbable plates was not stable. The zygomaticomaxillary pillars fixation is more stable than other fixations. The stability of fracture fixation was influenced with the molar occlusion. The current study developed a functional three-dimensional finite element model of bioabsorbable internal fixation and compared the stability of five fixation methods for maxillary Lefort Ι fractures. The results would facilitate the application of bioabsorbable materials in dental clinic.

Anterior cingulate cortex and cerebellar hemisphere neurometabolite changes in depression treatment: A 1H magnetic resonance spectroscopy study.

AIM: We utilized single-voxel 1H magnetic resonance spectroscopy to determine biochemical abnormalities related to major depressive disorder (MDD) in the bilateral dorsolateral prefrontal cortex, anterior cingulate cortex (ACC), and cerebellar hemisphere before and after antidepressant treatment. METHODS: Fifteen adult MDD patients and 15 age- and sex-matched healthy controls were involved. Magnetic resonance spectroscopy of the brain was conducted in all subjects at the beginning of the study and the depressed subjects were reassessed after 8 weeks of antidepressant treatment. RESULTS: At baseline, N-acetyl aspartate (NAA), total glutamine plus glutamate (Glx) and myo-inositol (MI) levels in the bilateral ACC were significantly lower in MDD patients than in controls (P < 0.05/3). MI in the bilateral cerebellar hemisphere were also decreased in patients compared with controls. After the treatment, the lower NAA, Glx and MI in ACC were normalized in MDD patients and the NAA and Glx increased compared to baseline values. The MI levels in the bilateral cerebellar hemisphere were also normalized in patients. MI and choline levels in the right cerebellar hemisphere were elevated compared to those at baseline. CONCLUSION: Our study suggests that metabolic abnormalities in the ACC and cerebellar hemisphere are implicated in MDD. Antidepressants may alter the local metabolic abnormalities in these areas.

Behavioral deficits, abnormal corticosterone, and reduced prefrontal metabolites of adolescent rats subject to early life stress.

The present study investigated the effect of early life stress in adolescent rats on brain metabolites, serum corticosterone, and depressive-like behavior. A group of rats was subject to early life stress from postnatal day (PND) 1 to 14. A matched control group was studied. Behavioral tests, serum corticosterone and high-resolution proton magnetic resonance spectroscopy were conducted between PND 30 and 40. In this study, adolescent rats exposed to early life stress demonstrated depressive-like behavior and increased serum corticosterone during adolescence. They also showed reduced glutamate, glutamine, and N-acetylaspartate (NAA) levels in the prefrontal cortex. A reduced myo-inositol level, consistent with astroglial deficits, was observed but was not statistically significant. Together, these findings characterize the effect of early life stress on adolescent animals and underscore the long-lasting and detrimental effects of childhood adversities.

Upregulation of adenosine A2A receptors induced by atypical antipsychotics and its correlation with sensory gating in schizophrenia patients.

Sensory gating deficits have been found in patients with schizophrenia and their unaffected relatives. However, the underlying neurobiological mechanism of this deficit remains unclear. Pre-clinical studies have implicated adenosine in sensory gating deficits in schizophrenia. Therefore, the current study investigated a possible relationship between peripheral adenosine A2A receptor (ADORA2A) and sensory gating indices (P50 measures) in medication-free schizophrenia (n=31) and healthy (n=21) groups. The effects of six-week antipsychotic treatment were examined. At baseline, schizophrenia patients showed impaired sensory gating compared to healthy controls. However, there was no significant difference in ADORA2A gene expression among groups. In addition, ADORA2A expression was not correlated with sensory gating at any time point. Following treatment, we found a significant upregulation of ADORA2A expression. Intriguingly, we observed a significant positive association between ADORA2A upregulation and baseline P50 amplitudes in the schizophrenia group. A main finding of the current pilot study is the upregulation of ADORA2A expression following treatment with antipsychotics. In addition, this upregulation was predicted by baseline P50 amplitude, an observation that awaits replication in an expanded sample.

[Finite element study of maxillary Le Fort-I osteotomy with rigid internal fixation].

OBJECTIVE: To study the biomechanical characteristic of maxillary Le fort- I osteotomy with rigid internal fixation (RIF) , so as to choose best fixation method. METHODS: The 3-dimensional finite element models of maxillary Le Fort-I osteotomy with 9 kinds of RIF methods were established. Then the models were divided into three groups to calculate the stress distribution of the maxilla and the displacement of bone segment under 3 kinds of occlusion condition. The fixation stability of the different RIF methods was evaluated. RESULTS: Under the incisor occlusion condition, the stress of the cranio maxillary complex transmits mainly along the nasal-maxillary buttress. Under the premolar and molar occlusion condition, the stress transmits along the alveolar process first, then turns to the nasal-maxillary and zygomatic-maxillary buttress. The focused stress position of the internal fixation system is at the connection between the screws and the plate and at the plate near the osteotomy line. Under the premolar occlusion condition, the displacement of bone segment with different RIF methods was (in a decreasing order) 0.396509 mm (with bio-absorbable plate), 0.148393 mm (with micro-plate ), 0.078436 mm (with mini-plate) in group 1; 0.188791 mm (fixing at the nasal-maxillary buttress), 0.121718 mm (fixing at the zygomatic-maxillary buttress), 0.078436 mm (fixing at the both buttress) in group 2; 0.091023 mm (with straight plate), 0.078436 mm (with L shape plate), 0.072450 mm (with Y shape plate), 0.065617 mm (with T shape plate) in group 3. CONCLUSIONS: The fixation stability of using the bio-absorbable plate in Le Fort-I osteotomy is less stable than using the titanium plate. Fixing at the zygomatic-maxillary buttress is more stable than at the naso-maxillary buttress. The fixation stability is different by using different shapes of plates.

[Establishment and primary analysis of the three-dimensional finite element model of mandibular bilateral sagittal split ramus osteotomy with rigid internal fixation].

OBJECTIVE: Establish the three-dimensional finite element models of mandibular bilateral sagittal split ramus osteotomy (BSSRO) with rigid internal fixation (RIF), for further study of BSSRO. METHODS: CT scanned technology and the finite element software (ANSYS) were used to establish the original three-dimensional model of mandible, modify the model to animate the BSSRO, then establish the model of RIF, last mesh the model to establish the finite element model of BSSRO with RIF. Apply 100 N occlusion force at the central incisor; calculate the stress distribution of the mandible and the RIF. RESULTS: Three-dimensional finite element models of BSSRO with RIF were established, such as miniplate model, bicortical fixation screw model. When biting with the incisor and fixed with upper plate, the stress of the medial screw position of the distal and medial segment of mandible is high. When fixed with bicortical fixation screw, the highest stress position located at the internal surface of the medial screw' s position of the distal segment of mandible. CONCLUSIONS: The mentioned methods proved feasible in establishing the finite element models of BSSRO with RIF . The models can be applied to the study of BSSRO with RIF.

[Transmission disequilibrium analysis of 1137-1140 Del GTGA frameshift mutation within the KCNN3 gene and schizophrenia based on family trios].

OBJECTIVE: To investigate the relationship between 1137-1140 Del GTGA in exon 1 at KCNN3 gene and schizophrenia. METHODS: The study included 289 subjects (affected 107; unaffected 182) from 95 schizophrenic trios. All subjects were collected from Han Chinese in south China and genotyped for 1137-1140 Del GTGA in KCNN3 using PCR and restriction endonuclease Dde I. All the affected patients met the CCMD-II-R criteria for schizophrenia. The haplotype-based haplotype relative risk(HHRR) and transmission/disequilibrium test(TDT) analyses were done in 95 schizophrenic trios. RESULTS: Comparative analysis on the distribution of alleles between the affected and unaffected parents(87 family trios) showed no significant difference(X(2)=0.253, P> 0.05). HHRR showed that KCNN3 gene alleles transmitted to the patients were not different from that of the non-transmitted parental alleles(X(2)=0.042, P> 0.05). TDT revealed that A(2) alleles were not preferentially transmitted to schizophrenic patients(X(2)=3.000, P=0.0833). CONCLUSION: In this study a lower frequency for 1137-1140 Del homozygote of KCNN3 gene was observed, and the HHRR and TDT analyses suggested that the 1137-1140 Del alleles of KCNN3 gene be unlikely to confer susceptibility to schizophrenia.

Effects of chronic stress and phenytoin on the long-term potentiation (LTP) in rat hippocampal CA1 region.

To investigate the changes of LTP in hippocampal CA1 region induced by chronic stress and the effect of phenytoin on them, thirty-two adult male Sprague-Dawley rats were randomly divided equally into four groups: control group, control-phenytoin group, stress-saline group and stress-phenytoin group. Isolated hippocampal slices of rats were used to observe the changes of long-term potentiation (LTP) in hippocampal CA1 field using electrophysiological technique. Amplitude of population spike (PS) and field excitatory postsynaptic potentials (fEPSPs) slope were used to indicate the changes of LTP. High-frequency stimulation (HFS) was applied to Schaffer collaterals of hippocampal CA3 field, and the changes of PS amplitude and fEPSPs slope in CA1 field were observed. The results showed that the LTP induction rate, the increases of PS amplitude and fEPSPs slope after HFS in control and stress-phenytoin groups were significantly greater than those in stress-saline group (P<0.05). There were no significant differences between control group and stressphenytoin group or between control and control-phenytoin groups in these indexes (P>0.05). It is suggested that chronic stress can damage the development of LTP in hippocampal CA1 field, while phenytoin can protect the LTP of stressed hippocampal slices in normal state.