学生课堂“走神”的实践分析

学生在课堂'走神'是课堂常见的注意力不集中现象。本文从教师开展课堂教学和学生课堂学习两个维度分析学生在课堂出现'走神'问题的原因,并提出相关的解决策略和措施。

“走神”现象浅论——淡谈汽车驾驶员行车安全问题

人们在观察现象,思考问题或者做某项事情的过程中,时有思想不集中,即所谓“走神”的感觉。从心理学的角度来说,乃是注意力不集中。如不加以调整,观察的现象则片面,思考的问题就不深刻,所做的事情也就难以取得理想的效果。汽车司机手握方向盘,肩负着确保国家和人民生命财产安全的神圣使命,工作中务必正视提高注意力,以最大限度避免“走神”现象的发生。

揭开人类“走神”之谜

据媒体报道，科学家正在研究一种普遍的心理现象——走神。我们常常因为走神而受到老师或领导的责备，当你走神时，往往被问：在胡思乱想什么呢？你一定会一愣，然后说：没想什么。但看得出来，你一定在想别的东西。其实，这只是游离思维在发挥作用。我们每一个人都会走神，而且是令人惊讶地频繁，无论你想不想避免，它都会出现。

“走神”排行榜

美好的时光总是短暂的,转瞬间,这学期要结束了。在这岁末年初的时候,我们班的同学经过激烈的评选、反复的辩论,终于选出了四大＂走神冠军＂。

Inhibiting effect of vagal nerve stimulation to seizures in epileptic process of rats

Objective Our previous work suggested that sensitivity of hippocampal neurons is changed in process of epileptic activities,and closely parallel to the dynamic characteristic of epileptic activity of the neurons.This study investigated the sensitivity of epileptic brain to vagal nerve stimulation（VNS）in epileptic process.Methods Epileptic model was evoked by penicillin.Left vagal nerves were stimulated to inhibit the seizures induced by penicillin.The electrocorticography（ECoG）and electromyography（EMG）were recorded to analyze inhibiting effect of VNS in epileptic process.Results It was found that VNS could inhibit the seizures caused by penicillin,and the inhibiting effect of VNS to seizures increased as the vagal nerve stimulating time prolonged.It was also found that the inhibiting effect of VNS to seizures decreased in epileptic process.Conclusion The results suggested that the sensitivity of epileptic brain to VNS was different in epileptic process.The inhibiting effect of VNS to seizure decreased as the development of seizures.

Gastric mucosal damage in water immersion stress:Mechanism and prevention with GHRP-6

AIM:To investigate the mechanism of gastric mucosal demage induced by water immersion restraint stress(WRS) and its prevention by growth hormone releasing peptide-6(GHRP-6).METHODS:Male Wistar rats were subjected to conscious or unconscious(anesthetized) WRS,simple restraint(SR),free swimming(FS),non-water fluid immersion,immersion without water contact,or rats were placed in a cage surrounded by sand.To explore the sensitivity structures that influence the stress reaction besides skin stimuli,a group the rats had their eyes occluded.Cervical bilateral trunk vagotomy or atropine injection was performed in some rats to assess the parasympathetic role in mucosal damage.Gastric mucosal lesions,acid output and heart rate variability were measured.Plasma renin,endothelin-1 and thromboxane B2 and gastric heat shock protein 70 were also assayed.GHRP-6 was injected [intraperitoneal(IP) or intracerebroventricular(ICV)] 2 h before the onset of stress to observe its potential prevention of the mucosal lesion.RESULTS:WRS for 6 h induced serious gastric mucosal lesion [lesion area,WRS 81.8 ± 6.4 mm 2 vs normal control 0.0 ± 0.0 mm 2,P < 0.01],decreased the heart rate,and increased the heart rate variability and gastric acid secretion,suggesting an increase in vagal nervecarrying stimuli.The mucosal injury was inversely correlated with water temperature(lesion area,WRS at 35 ℃ 56.4 ± 5.2 mm 2 vs WRS at 23 ℃ 81.8 ± 6.4 mm 2,P < 0.01) and was consciousness-dependent.The injury could not be prevented by eye occlusion,but could be prevented by avoiding contact of the rat body with the water by dressing it in an impermeable plastic suit.When water was replaced by vegetable oil or liquid paraffin,there were gastric lesions in the same grade of water immersion.When rat were placed in a cage surrounded by sand,there were no gastric lesions.All these data point to a remarkable importance of cutenuous information transmitted to the high neural center that by vagal nerves reaching the gastric mucosa.FS alone also induced serious gastric injury,but SR could not induce gastric injury.Bilateral vagotomy or atropine prevented the WRS-induced mucosal lesion,indicating that increased outflow from the vagal center is a decisive factor in WRS-induced gastric injury.The mucosal lesions were prevented by prior injection of GHRP-6 via IP did,but not via ICV,suggesting that the protection is peripheral,although a sudden injection is not equivalent to a physiological release and uptake,which eventually may affect the vagal center.CONCLUSION:From the central nervous system,vagal nerves carry the cutaneous stimuli brought about by the immersion restraint,an experimental model for inducing acute gastric erosions.GHRP-6 prevents the occurrence of these lesions.

Effects of nuclei ambiguus and dorsal motor nuclei of vagus on gastric H^+ and HCO_3^- secretion in rats

AIM: To determine the effects of electrical stimulation of nucleus ambiguus (NA) and dorsal motor nuclei of vagus (DMV) on gastric acid and bicarbonate secretion in rats. METHODS: NA and DMV in rats were electrically stimulated. Pylorus ligation or esophagus perfusion was used to collect the gastric secretion. The titratable H+ quantum, H+ concentration, HCO3- secretion quantum were measured. RESULTS: Electrical stimulation of NA had no effects on the volume of gastric juice, titratable acidity and acid concentration, but elicited a pronounced increase in the total bicarbonate. However, electrical stimulation of DMV significantly increased the titratable acidity, the volume of gastric juice and the acid concentration. Similarly, electrical stimulation of either NA or DMV decreased the respiratory frequency and sinus bradycardia. CONCLUSION: NA in rats can not control the secretion of gastric acid but the secretion of bicarbonate in gastric juice, while DMV controls the secretion of gastric acid.

Pseudoachalasia in a patient after truncal vagotomy surgery successfully treated by subsequent pneumatic dilations

Pseudoachalasia is a difficult condition for the clinician to differentiate from idiopathic achalasia even by manometry, radiological studies or endoscopy. Its etiology is usually associated with tumors. In most cases, the diagnosis is made after surgical explorations. The proposed pathogenesis of the disease is considered as mechanical obstruction of the distal esophagus or infiltration of the malignancy that affects the inhibitory neurons of the meyenteric plexus in the majority of cases. Surgery has been reported as a cause of pseudoachalasia. We report a 70-year-old man who suffered from deglutination disorder caused by pseudo-achalasia after truncal vagotomy. The patient was symptom-free after a nine-year follow-up and complete recovery of esophageal motility status from pseudoachalasia after pneumatic dilations. We also reviewed the literature of pseudoachalasia.

Barrett's esophagus with high-grade dysplasia:Focus on current treatment options

High-grade dysplasia(HGD) in Barrett's esophagus(BE) is the critical step before invasive esophageal adenocarcinoma.Although its natural history remains unclear,an aggressive therapeutic approach is usually indicated.Esophagectomy represents the only treatment able to reliably eradicate the neoplastic epithelium.In healthy patients with reasonable life expectancy,vagal-sparing esophagectomy,with associated low mortality and low early and late postoperative morbidity,is considered the treatment of choice for BE with HGD.Patients unfit for surgery should be managed in a less aggressive manner,using endoscopic ablation or endoscopic mucosal resection of the entire BE segment,followed by lifelong surveillance.Patients eligible for surgery who present with a long BE segment,multifocal dysplastic lesions,severe reflux symptoms,a large fixed hiatal hernia or dysphagia comprise a challenging group with regard to the appropriate treatment,either surgical or endoscopic.

Serious response during tilt-table test in elderly and its prophylactic management

Objective: To evaluate the serious response during tilt-table test (TTT) and its prophylactic management. Method: Seventy-six elderly patients were tested at a tilt angle of 70 degrees for a maximum of 45 min and then subjected to isoprotere- nol-provocative tilt testing. ECG and blood pressure were monitored during the test and patients were kept at normal saline con- dition through a peripheral intravenous duct. Results: Fifty-one of 76 patients were defined as positive including 23 having serious response; 6 of the 23 patients had arteriosclerosis involving internal carotid arteries and 7 cases had bradycardia, two of which were associated with II°-I A-V block and the others with chronic atrial fibrillation. The serious response consisted of cardiac arrest for more than 5 s (6 cases), or serious bradycardia for more than 1 min (7 cases) or serious hypotension for more than 1 min (10 cases). Those with serious response were managed by returning to supine position, thus driving up legs and intravenous atropine, CPR (2 cases with cardiac arrest) and needing oxygen supplementation (11 cases). Only 2 hypotension patients recovered gradually by 10 min after emergency management, while others recovered rapidly with no complications. Conclusion: Although non-invasive, TTT may result in serious response, especially in elderly. Therefore proper patient selection, control of isoproterenol infusion and close observation of vital signs are decisive for a safe consequence.

Effect of Efferent Vagus Nerve Excitation by Electrical Stimulation on Acute Liver Injury in Rabbits with Endotoxemia

Objective:To study the effect of electrical stimulation of efferent vagus nerve on the acute liver injury induced by endotoxemia in rabbits. Methods:Sixteen rabbits were randomly divided into stimulation group(Group A,n=8) and control group (Group B,n=8).They were subjected to bilateral cervical vagotomy and intravenously challenged by lipopolysaccharide (LPS) (E.coli 0111:B4,DIFCO,USA) at a dose of 100 μg/kg injected within 30 min.The distal end of the left vagus nerve trunk was placed across bipolar electrodes connected to a stimulation module and controlled by an acquisition system.Stimuli with constant voltage (10V,5Hz,5ms) were applied twice to the nerve for 10 min before and after the administration of LPS in Group A.At the time 30,60,120,180,240,300 min before and after infusion of LPS respectively in each animal,blood samples were taken for late measurement of the serum Alanine aminotransferase (ALT),Aspartate aminotransferase (AST),tumor necrosis factor-α(TNF-α) and interleukin-10 (IL-10).Immediately after the experiment was finished,autopsy was performed and liver samples were taken to pathologic study. Results:Compared with Group B,the electrical stimulation of efferent vagus nerve could significantly decrease the contents of ALT,AST and TNF-α,but increase the contents of IL-10,in serum of Group A.It could also alleviate inflammation of liver tissue after LPS attack. Conclusion:The results suggest that excitation of the efferent vagus nerve can inhibit the inflammation cascade in liver after LPS challenge.Thus,it might have a protective effect on acute liver damage caused by endotoxemia.

Effects of vagus nerve preservation and vagotomy on peptide YY and body weight after subtotal gastrectomy

AIM:To investigate the relationship between the function of vagus nerve and peptide YY 3-36 and ghrelin levels after subtotal gastrectomy.METHODS:We enrolled a total of 16 patients who underwent subtotal gastrectomy due to gastric cancer.All surgeries were performed by a single skilled surgeon.We measured peptide YY 3-36,ghrelin,leptin,insulin,growth hormone levels,and body weight immediately before and one month after surgery.RESULTS:Vagus nerve preservation group showed less body weight loss and less increase of peptide YY 3-36 compared with vagotomy group(-5.56 ± 2.24 kg vs-7.85 ± 1.57 kg,P = 0.037 and 0.06 ± 0.08 ng/mL vs 0.19 ± 0.12 ng/mL,P = 0.021,respectively).Moreover,patients with body weight loss of less than 10% exhibited reduced elevation of peptide YY 3-36 level,typically less than 20% [6(66.7%) vs 0(0.0%),P = 0.011,odd ratio = 3.333,95% confidence interval(1.293,8.591)].CONCLUSION:Vagus nerve preservation contributes to the maintenance of body weight after gastrectomy,and this phenomenon may be related to the suppressed activity of peptide YY 3-36.

Adult Medulloblastoma Associated with Syringomyelia:A Case Report

The association between cerebellar medulloblastoma and syringomyelia is uncommon and only found in pediatric patients.To date,adult medulloblastoma associated with syringomyelia has not been reported in the literature.Paroxysmal bradycardia is an uncommon clinical manifestation in posterior fossa tumors and likely to be vagally mediated via brainstem preganglionic cardiac motor neurons.This report introduces the diagnosis and treatment of a case of adult medulloblastoma associated with syringomyelia, which presented with paroxysmal bradycardia.

AN UNUSUAL BILATERAL VAGAL PARAGANGLIOMAS: ONE CASE STUDY

VAGAL paraganglioma （VP） is an uncommon neoplasm originating from neural crest paraganglion cells located along the vagus nerve, repre-senting less than 5 % of all paragangliomas of the head and neck Despite improvement in microsurgical techniques,

Effects of highly selective vagotomy plus resection of antral mucosa or highly selective vagotomy alone on motility function of pyloric antrum

Objective: To study the effects of highly selective vagotomy plus resection of antral mucosa (HSV+RAM) or highly selective vagotomy (HSV) alone on the motility function of the pyloric antrum. Methods: 48 patients with duodenal ulcer were studied. 18 dogs were employed as experimental animals. 20 patients were operated on with HSV and 28 with HSV+RAM. The frequency of gastric evacuation and the amplitude of electrogastrography were determined 4 to 6 months after operation. 18 dogs were divided into the control group, HSV group and HSV+RAM group. The time of gastric evacuation, antral myoelectric activity and antral pressure were determined in the dogs 4 to 6 months after operation. The preoperative findings of the patients and the control dogs served as the control. Results: After operation, barium meal revealed that the shape of the stomach and duodenum was normal and the gastric peristalsis was clearly visible in human patients and experimental dogs. In the HSV+RAM group of dogs, the initial evacuation time was (5.0+0.06) min and the time of complete evacuation was (4.0+0.4) h after food-taking, which were similar to those of the control and the HSV group of dogs (P>0.05). The frequency of the antral myoelectric action potential was (3.11+0.65) cycles/min in the dog HAS+RAM group and the frequency of electrogastrography was (3.25+0.75) cycles/min in the human HSV+RAM group, which were significantly lower than those of the control and the dog and human HSV groups (P<0.05). Injection of pentagastrin in dogs and food-taking in human beings significantly increased the antral pressure and the amplitude and frequency of electrogastrography. Conclusion: The findings of this study suggest that the motility function of the reconstructed pyloric antrum in the HSV+RAM group of both the experimental dogs and human patients approaches to the normal even though there is a decrease of antral myoelectric frequency. It is suggested that HSV+RAM should be the first choice for the surgical management of duodenal ulcer.

INTRAPANCREATIC CHOLECYSTOKININ MEDIATES VAGALLY STIMULATED EXOCRINE SECRETION FROM THE RAT PANCREAS

Although cholecystokinin is localized within neuronal fibres of the pancreas, a physiological role for intrapancreatic cholecystokinin has not been identified. The strategy of this study was to elicit pure vagal stimulation electrically, and to use specific receptor antagonists to identify the mediators of exocrine pancreatic secretion. We conclude that vagal stimulation of the rat pancreas involves ganglionic neurotransmission and release of acetylcholine and cholecystokinin from intrapancreatic, postganglionic fibres. To our knowledge, this is the first study to demonstrate a physiological role for intrapancreatic cholecystokinin.

An adult case of celiac sprue triggered after an ileal resection for perforated Meckel's diverticulum

Celiac disease can be triggered by upper abdominal surgery, such as vagotomy, oesophagectomy, pancreatico-duodenectomy, and gastrojejunal anastomosis. Here we report a case of a 24 year-old woman who developed celiac disease after an ileal resection for perforated Meckel's diverticula. This is the first reported celiac case that has been triggered, not by upper abdominal surgery, but after ileal resection for Meckel's diverticula.

Vagus-preserving Merendino-Procedure for Early Carcinoma ofthe Gastroesophageal Junction

Optimal therapy for early carcinoma of the gastroesophageal junction remains uncertain. Treat- ment alternatives discussed today reach from endoluminal techniques to radical esophagectomy with 2- or 3-?eld lymphadenectomy. In this context, the Merendino procedure with preservation of the vagal innerva- tion to the stomach appears as an interesting therapeutic alternative. This paper summarizes indications, operative technique, and functional results with respect to postoperative quality of life, based upon 2 cases operated in our department.

A new partial trisomy 12p with artery catheter vagus,congenital cataract,no turbinate and external auditory canal

We describe the prenatal diagnosis and fetal phenotype of partial trisomy 12 （pl2-pter） transmitted from a maternal reciprocal translocation 6;12. Genetic analysis of umbilical cord blood of a 27-year-old woman, gravida 4, para 1 at 35 weeks＇ gestation due to a tricuspid regurgitation and orbital hypertelorism by sonography revealed an unusual karyotype of 46, XY, der （6） t （6;12） （p24;p12） mat. The pregnancy was terminated at 37 gestational weeks. The proband postnatally displayed by dysmorphic features of a round flat face with prominent cheeks and high forehead, hypertelorism, a short nose, a broad and depressed nasal bridge, anteverted nares, a deformed philtrum, an open mouth, thin upper vermilion and broad everted lower lip, low-set ears and aural atresia, broad hands with simian creases, and a short neck. By anatomy, the fetal was found to have right artery catheter vagus, congenital cataract, no turbinate and external auditory canal. Through the karoytpye-phynotpye analysis on the present patient and a review of other reported cases, we believed that the case was the first report, which expanded the database of partial trisomy 12p, and was of benefit for future clinical genetic counseling. At the same time, this study supported the viewpoint that phenotypic variability depends on the type and extent of the associated partial monosomy