Low-dose Simvastatin Increases Skeletal Muscle Sensitivity to Caffeine and Halothane.

Objective To determine whether the myotoxic side effects of statin simvastatin affect skeletal muscle's sensitivity to caffeine and halothane.Methods Primary cultured neonate rat skeletal myotubes were treated with 0.01-5.0 µmol/L simvastatin for 48 hours. MTT was used to evaluate cellular viability. The gross morphology and microstructure of the myotubes were observed with a light and electron microscope, respectively. The intracellular calcium concentrations ([Ca2+]i) at rest and in response to caffeine and halothane were investigated by fluorescence calcium imaging. Data were analyzed by analysis of variance (ANOVA) test.Results Simvastatin (0.01-5.0 µmol/L) decreased myotube viability, changed their morphological features and microstructure, and increased the resting [Ca2+]i in a dose-dependent manner. Simvastatin did not change myotube's sensitivity to low doses of caffeine (0.625-2.5 mmol/L) or halothane (1.0-5.0 mmol/L). In response to high-dose caffeine (10.0 mmol/L, 20.0 mmol/L) and halothane (20.0 mmol/L, 40.0 mmol/L), myotubes treated with 0.01 µmol/L simvastatin showed a significant increase in sensitivity, but those treated with 1.0 µmol/L and 5.0 µmol/L simvastatin showed a significant decrease. The sarcoplasmic reticulum Ca2+ storage peaked in the myotubes treated with 0.01 µmol/L simvastatin, but it decreased when cells were treated with higher doses of simvastatin (0.1-5.0 µmol/L).Conclusions The myotoxic side effect of simvastatin was found to change the sensitivity of myotubes in response to high-dose caffeine and halothane. When dose was low, sensitivity increased mainly because of increased Ca2+ content in the sarcoplasmic reticulum, which might explain why some individuals with statin-induced myotoxic symptoms may show positive caffeine-halothane contracture test results. However, when the dose was high and the damage to the myotubes was severer, sensitivity was lower. It is here supposed that the damage itself might put individuals with statin-induced myotoxic symptoms at greater risks of presenting with rhabdomyolysis during surgery or while under anesthesia.

Parental state anxiety correlates with preoperative anxiety in Chinese preschool children.

AIM: Preoperative anxiety in children is largely dependent on age and is influenced by anxiety level in parents. The current study compared the level of preoperative anxiety in preschool children versus school-aged children and its relationship with the state and trait anxiety of the parents. METHODS: This study included 54 preschool children (2-5 years of age) and 48 school-age children (6-12 years) scheduled to receive ear, nose and throat, plastic or ophthalmologic surgeries. Preoperative anxiety of children was assessed in the holding area immediately prior to the surgery using a modified Yale Preoperative Anxiety Scale (m-YPAS). Compliance with anaesthesia induction was assessed using an Induction Compliance Checklist (ICC). The state and trait anxiety of the parent who accompanied the child was assessed using a State-Trait Anxiety Inventory (STAI) questionnaire. RESULTS: Both m-YPAS and ICC scores were higher in preschool children than in school-age children with significant correlation between the two measures. The STAI-S score of parents was higher in the preschool group than in the school-age group. No significant difference was found in STAI-T score between the two age groups. Children's m-YPAS score correlated with parental STAI-T score in both groups (rho = 0.297, P = 0.029 and rho = 0.338, P = 0.019, respectively) but only with STAI-S score in the preschool group (rho = 0.400, P = 0.003). CONCLUSIONS: Both preschool children and their parents are more anxious than school-age dyads prior to surgery. The anxiety level of the children correlates with state anxiety of the parents in preschool children but not in school-age children.

Glutaminase 1 is a potential biomarker for chronic post-surgical pain in the rat dorsal spinal cord using differential proteomics.

Chronic post-surgical pain (CPSP) is a normal and significant symptom in clinical surgery, such as breast operation, biliary tract operation, cesarean operation, uterectomy and thoracic operation. Severe chronic post-surgical pain could increase post-surgical complications, including myocardial ischemia, respiratory insufficiency, pneumonia and thromboembolism. However, the underlying mechanism is still unknown. Herein, a rat CPSP model was produced via thoracotomy. After surgery, in an initial study, 5 out of 12 rats after surgery showed a significant decrease in mechanical withdrawal threshold and/or increase in the number of acetone-evoked responses, and therefore classified as the CPSP group. The remaining seven animals were classified as non-CPSP. Subsequently, open-chest operation was performed on another 30 rats and divided into CPSP and non-CPSP groups after 21-day observation. Protein expression levels in the dorsal spinal cord tissue were determined by 12.5 % SDS-PAGE. Finally, differently expressed proteins were identified by LC MS/MS and analyzed by MASCOT software, followed by Gene Ontology cluster analysis using PANTHER software. Compared with the non-CPSP group, 24 proteins were only expressed in the CPSP group and another 23 proteins expressed differentially between CPSP and non-CPSP group. Western blot further confirmed that the expression of glutaminase 1 (GLS1) was significantly higher in the CPSP than in the non-CPSP group. This study provided a new strategy to identify the spinal proteins, which may contribute to the development of chronic pain using differential proteomics, and suggested that GLS1 may serve as a potential biomarker for CPSP.

Pheochromocytoma crisis with severe cyclic blood pressure fluctuations in a cardiac pheochromocytoma patient successfully resuscitated by extracorporeal membrane oxygenation: a case report.

Cardiac pheochromocytoma is relatively rare. Few reports describe the intraoperative and postoperative progression of patients experiencing a life-threatening pheochromocytoma crisis treated with extracorporeal membrane oxygenation (ECMO).A 35-year-old man was referred to our facility for paroxysmal hypertension with a 10-year history of sweating, headaches, cardiac palpitations, and postexercise dyspnea. The patient initially underwent urine catecholamine measurement and an isotope scan, somatostatin receptor scintigraphy, and 18F-fluorodeoxyglucose positron emission tomography/computer tomography (CT), which indicated a multiple, cardiac pheochromocytoma. Echocardiography, cardiac magnetic resonance imaging (MRI), CT reconstruction, and a coronary CT angiography revealed several lesions at the aortic root and along the cardiac vasculature.Multifocal cardiac pheochromocytoma was diagnosed and pheochromocytoma crisis with severe cyclic blood pressure fluctuation occurred during surgery.Surgical resection of multiple pheochromocytomas in the right medial carotid sheath, mediastinum between the main and pulmonary arteries, and between the abdominal aorta and inferior vena artery was performed. To ensure cardiac perfusion and avoid severe circulatory fluctuation, the cardiac paraganglioma resection was prioritized. After resecting the cardiac pheochromocytoma, a severe pheochromocytoma crisis with rapid cyclic blood pressure fluctuation developed. ECMO and intraaortic balloon pump (IABP) were initiated to stabilize circulation and perfusion. Phenoxybenzamine, norepinephrine, epinephrine, and fluid resuscitation were administered to support cardiovascular function.The magnitude of blood pressure fluctuation steadily decreased with treatment. IABP was discontinued after 3 days, and ECMO was discontinued after 16 days. The patient was discharged 3 months postoperatively.This case indicates that mechanical life support with ECMO is a valuable option for pheochromocytoma-induced cardiac shock and should be considered as an effective therapeutic choice in patients with highly unstable hemodynamic function.

[Influence of different tranexamic acid administration methods during and after cardiac surgery on coagulation function and postoperative blood loss].

OBJECTIVE: To evaluate the influence of different tranexamic acid administration methods during and after cardiac surgery with cardiopulmonary bypass(CPB) on coagulation function and postoperative bleeding. METHODS: Patients undergoing elective cardiac surgery with use of CPB (n=60) were randomized in a double-blind fashion to one of two treatment groups:group A(n=30) , administered with tranexamic acid 10 mg/kg (intravenous injection slowly before skin incision) , followed by infusion of normal saline until postoperative 12 hours;and group B(n=30) , administered with tranexamic acid 10 mg/kg(intravenous injection slowly before skin incision) , followed by infusion of tranexamic acid 1 mg/(kg·h) until postoperative 12 hours. Hemoglobin, platelet count, and coagulation function were assessed before anesthesia induction, after surgery, 8am next day and 24 hours after surgery. Bleeding, allogeneic blood transfusion, and fluid infusion during the postoperative 24 hours were recorded. RESULT: No differences were found between groups in terms of coagulant function, postoperative bleeding, allogeneic blood transfusion, and fluid infusion(P>0.05) . CONCLUSION: Compared with intraoperative administration alone, prolonged treatment with tranexamic acid after cardiac surgery shows no advantage because it can not further improve coagulant function, reduce bleeding, or reduce allogeneic blood transfusion.

Perioperative smoking behavior of Chinese surgical patients.

BACKGROUND: Surveys suggest that, consistent with a high smoking prevalence, Chinese smokers in the general population report little interest in quitting. In other cultures, surgery is a powerful teachable moment for smoking cessation, increasing the rate of spontaneous quitting. We determined the perioperative tobacco use behavior of Chinese patients scheduled for elective surgery who smoke cigarettes and factors associated with both preoperative intent to abstain and self-reported smoking behavior at 30 days postoperatively. Specifically, we tested the hypothesis that perception of the health risks of smoking would be independently associated with both preoperative intent to abstain and self-reported abstinence at 30 days postoperatively. METHODS: Patients ≥18 years of age scheduled for elective noncardiovascular surgery at Peking Union Medical College Hospital in Beijing, China, were assessed preoperatively and up to 30 days postoperatively for factors associated with smoking behavior, including indices measuring knowledge of smoking-related health risks. RESULTS: Of the 227 patients surveyed at baseline, most (164, 72%) intended to remain abstinent after hospital discharge. For the 204 patients contacted at 30 days postoperatively, 126 (62%) self-reported abstinence. In multivariate analysis, factors associated with preoperative intent to abstain after surgery included older age, self-efficacy for abstaining, and undergoing major surgery; factors associated with abstinence included older age, self-efficacy, major surgery, and preoperative intent to abstain. Higher perception of benefits from quitting was associated with intent, but not abstinence. Knowledge of the health risks caused by smoking was not found to be associated with either intent or abstinence, so that the hypothesis was not supported. CONCLUSIONS: Both intent to quit and self-efficacy for maintaining abstinence appear to be much higher in Chinese surgical patients than in prior surveys of the general Chinese population, and the majority of surgical patients maintained abstinence for at least 30 days. These findings suggest that surgery can serve as a powerful teachable moment for smoking cessation in China.

Melatonin premedication attenuates isoflurane anesthesia-induced ß-amyloid generation and cholinergic dysfunction in the hippocampus of aged rats.

Melatonin plays an important role in aging and relevant neurodegeneration as an antioxidant and neuroprotector. It can interact with ß-amyloid (Aß) generation, inhibit formation of ß-sheet and amyloid fibrils, modulate apoptosis, and protect cholinergic system function in Alzheimer's disease animal model. Recently, its effects on anesthetic-induced neurodegeneration have received more attention, and in this investigation, we explored whether melatonin can attenuate Aß(1-40) generation and cholinergic dysfunction in the hippocampus of aged rats induced by isoflurane through enzyme-linked immunosorbent assay, Western blot, immunohistochemistry, and immunofluorescence. The results showed that isoflurane increased Aß(1-40) generation and caused cholinergic dysfunction through decreasing choline acetyltransferase (ChAT) expression in the hippocampus in a dose-dependent way, and intraperitoneal melatonin premedication attenuated the neurodegeneration through inhibiting Aß(1-40) generation and increasing ChAT expression, and its effects were more obvious in high-concentration isoflurane group. Collectively, our results provide evidence for the therapeutic value of melatonin on isoflurane-induced neurodegeneration, including Aß(1-40) generation and cholinergic dysfunction, and further work is necessary to clarify its target sites and detailed mechanisms.

Prevalence and risk factors of chronic post-thoracotomy pain in Chinese patients from Peking Union Medical College Hospital.

BACKGROUND: In clinical practice, the mechanisms underlying chronic post-surgical pain (CPSP) remain insufficiently understood. The primary goals of this study were to determine the incidence of chronic pain after thoracic surgery and to identify possible risk factors associated with the development of chronic post-thoracotomy pain in Chinese patients. The secondary goal was to determine whether the difference between pre- and post-operative white blood cell (WBC) counts could predict the prevalence of CPSP after thoracotomy. The impact of chronic pain on daily life was also investigated. METHODS: We contacted by phone 607 patients who had undergone thoracotomy at our hospital during the period February 2009 to May 2010. Statistical comparisons were made between patients with or without CPSP. RESULTS: were ultimately analyzed from 466 qualified patients. The overall incidence of CPSP was 64.5%. Difference between pre- and post-operative WBC counts differed significantly between patients with or without CPSP (P < 0.001) and was considered as an independent risk factor for the development of CPSP following thoracotomy (P < 0.001). Other predictive factors for chronic pain included younger age (< 60 years, P < 0.001), diabetes mellitus (P = 0.023), acute post-operative pain (P = 0.005) and the duration of chest tube drainage (P < 0.001). At the time of interviews, the pain resulted in at least moderate restriction of daily activities in 15% of the patients, of which only 16 patients had paid a visit to the doctor and only three of them were satisfied with the therapeutic effects. CONCLUSIONS: Chronic pain is common after thoracotomy. WBC count may be a new independent risk factoring surgical patients during peri-operative period. Besides, age, diabetes mellitus, acute post-operative pain, and duration of chest tube drainage may also play a role in chronic post-surgical pain occurrence.

[Analgesic effect of calpain inhibitor ALLN on the zymosan-induced paw inflammatory pain and its effect on the expression of cyclooxygenase-2 in the spinal dorsal horn].

OBJECTIVE: To examine the analgesic effect of calpain inhibitor ALLN on the zymosan-induced paw inflammatory pain and its effect on the expression of cyclooxygenase-2 (COX-2) in the spinal dorsal horn. METHODS: Forty-eight Sprague-Dawley rats were equally divided into three groups: control group, sham-operated group, and zymosan group. According to Meller's method, zymosan (1.25 mg) was injected intraplantarly to induce paw inflammation in zymosan group; an equal volume of PBS was administered in the sham-operated group. Mechanical withdrawal threshold (MWT) and maximum thickness of paw were tested or measured before and 0.5, 1, 2, 4, 8, and 24 hours after injection. All rats were killed at different occasions following surgery to examine calpain activity in the spinal dorsal horn with Western blot analysis. Another sixty-four Sprague-Dawley rats were divided into three groups: sham-operated group, zymosan-induced paw inflammation with intraperitoneal dimethyl sulphoxide (DMSO) treatment group, and zymosan-induced paw inflammation with intraperitoneal calpain inhibitor ALLN treatment group. MWT and maximum thickness of paw were tested or measured before and 0.5, 1, 2, 4, 8, and 24 hours after injection. All rats were killed at different occasions following surgery to examine the COX-2 expression in the spinal dorsal horn with Western blot analysis. RESULTS: MWT significantly decreased in the rats with zymosan-induced paw inflammation, while the maximum thickness of paw significantly increased, compared with control and sham-operated rats (P < 0.05). Calpain in the ipsilateral spinal dorsal horn was dramatically activated after zymosan injection (P < 0.01). Intraperitoneal ALLN injection significantly increased zymosan-induced MWT and decreased paw edema at the same time points after zymosan injection compared with DMSO treatment group (P < 0.05). Meanwhile, calpain inhibitor ALLN treatment significantly decreased the COX-2 expression in the spinal dorsal horn compared with DMSO treatment (P < 0.01). CONCLUSION: Administration of calpain inhibitor ALLN is effective to attenuate zymosan-induced paw inflammatory pain. Calpain activation may be one aspect of the signaling cascade that increases the COX-2 expression in the spinal cord and contributes to mechanical hyperalgesia after peripheral inflammatory injury.

Endogenous enkephalin does not contribute to the cerebral anti-hyperalgesic action of gabapentin.

The aim of this study was to investigate the role of endogenous enkephalin in the cerebral antihyperalgesic action of gabapentin. Neuropathic pain models and antihyperalgesic effect of gabapentin were confirmed by the presentation and changes of mechanical allodynia and thermal hyperalgesia of operated mouse hind paws. The results suggested that endogenous enkephalin may not be involved in the antihyperalgesic effect of gabapentin.

[Application of propofol target controlled infusion combined with dribbled and nebulized lidocaine in tracheal intubation under spontaneous respiration].

OBJECTIVE: To evaluate the value of propofol target-controlled infusion combined with dribbled and nebulized lidocaine in tracheal intubation under spontaneous breathing. METHODS: Totally 40 elective surgery patients to accept tracheal intubation under unconsciousness and spontaneous breathing were randomly divided into 2 groups: 6-8 cm of endotracheal tube was inserted subglottic ally in the complete intubation group (n=20) while 3-4 cm was inserted temporarily in the partial intubation group (n=20). RESULTS: The tracheal intubation was successfully completed under spontaneous breathing in all patients; meanwhile,the hemodynamic status was stable without any severe respiratory complications. Eleven patients suffered from moderate coughing response in the complete intubation group while no such response was noted in the partial intubation group (P<0.01). CONCLUSIONS: Application of propofol target-controlled infusion combined with dribbled and nebulized lidocaine provides a good condition for tracheal intubation under unconsciousness and spontaneous breathing. The partial intubation can effectively prevent the occurrence of coughing response.

[Application of lumber plexus blockade for hip fracture repair in elderly patients].

OBJECTIVE: To evaluate the lumber plexus blockade as anesthesia technique for hip fracture repair in elderly patients. METHODS: We retrospectively analyzed the peri-operative data of 87 hip fracture patients, aged 70 years or older, who underwent surgical repair at our hospital between 2003 and 2006. Patients were divided into three groups according the anesthesia techniques applied: general anesthesia (GA) group (n=21), epidural anesthesia (EA) group (n=37), and lumber plexus blockade (LPB) group (n=29). RESULTS: The peri-operative data were comparable among three groups, except that intra-operative the dosage of fentanyl was significantly lower in LPB group compared with in GA group(P0.05), and the blood urea nitrogen 1 day after surgery was significantly increased in GA group(P0.05). CONCLUSION: Lumber plexus blockade combined with small-dose intravenous anesthesia is an optional anesthetic technique for elderly patients undergoing hip fracture repair.

Clinical features and diagnosis for Chinese cases with malignant hyperthermia: a case cluster from 2005 to 2007.

BACKGROUND: Malignant hyperthermia (MH), manifesting as MH crisis during and/or after general anesthesia, is a potentially fatal disorder in response to volatile anesthetics and depolarizing muscle relaxants. Though typical features of MH episode can provide clues for clinical diagnosis, MH susceptibility is confirmed by in vitro caffeine-halothane contracture test (CHCT) in western countries. It is traditionally thought that MH has less incidence and fewer typical characteristics in Chinese population than their western counterparts because of the different genetic background. In this study, we investigated the clinical features of MH in Chinese cases and applied the clinical grading scale and CHCT for diagnosis of MH. METHODS: A cluster of three patients with MH, from January 2005 to December 2007, were included in the study. Common clinical presentations and the results of some lab examinations were reported in detail. The method of the clinical grading scale of diagnosis of MH was applied to estimate the qualitative likelihood of MH and predict MH susceptibility. Muscle fibers of femoral quadriceps of the patients were collected and CHCT was performed to confirm the diagnosis of MH. RESULTS: The clinical grading scales of diagnosis of the disease for these cases were all ranked grade D6, suggesting almost diagnosed ones. And the results of caffeine test were positive correspondingly, indicating that the patients should be diagnosed as MH susceptibility (MHS) according to diagnostic criteria of the North America MH group, which were already confirmed by clinical presentations and biochemical results. CONCLUSIONS: These Chinese cases manifest as MH crisis. The clinical grading scale of diagnosis of MH may provide clues for clinical diagnosis. CHCT can also be used in confirming diagnosis of MH in Chinese cases though they have different genetic background from their western counterparts.

[Effects of residual paralysis after a single intubating dose of rocuronium on postoperative pulmonary function of patients undergoing laparoscopic gynecological surgeries].

OBJECTIVE: To evaluate the residual paralysis after a single intubating dose of rocuronium and its effect of residual paralysis after a single dose of rocuronium on the postoperative pulmonary function of patients undergoing laparoscopic gynecological surgeries. METHODS: Sixty American Society of Anesthesiologists (ASA) I - II patients undergoing laparoscopic gynecological surgeries were randomly divided into rocuronium (R) group (n = 30) and rocuronium + neostigmine (R + N) group (n = 30).All patients received midazolam (0.02 mg/kg), fentanyl (1 microg/kg), propofol(1.5-2 mg/kg), and rocuronium (0.6 mg/kg) to facilitate tracheal intubation and no more relaxant thereafter. Anesthesia was maintained with isoflurane and nitrous oxide in oxygen (N(2)O:O(2) = 1:1). At the end of the procedure, neuromuscular blockade was not reversed in R group, while antagonism was accomplished with neostigmine (0.04 mg/kg) and atropine (0.02 mg/kg) in R + N group. Immediately after tracheal extubation and on arrival in the PACU, the train-of-four (TOF) ratio at the adductor pollicis of all patients were measured using acceleromyography. Forced vital capacity (FVC), forced expiratory volume in one second (FEV(1)), and peak expiratory flow rate (PEFR) of all patients were measured using spirometry before surgery, after administration of midazolam and fentanyl, immediately after tracheal extubation, on arrival in the PACU, and after the TOF ratio recovered to 1.0. The TOF ratio and pulmonary function between two groups were compared. RESULTS: Immediately after tracheal extubation and on arrival in the PACU, the mean TOF ratio in R group was significantly lower than that in R + N group (P < 0.05). The mean time to achieve TOF ratio of 0.9 and 1.0 in R group was significantly longer than in R + N group (P < 0.05). Immediately after tracheal extubation and on arrival in the PACU, FVC, FEV(1), and PEFR were significantly lower in R group than in R + N group (P < 0.05). FVC, FEV(1), and PEFR after administration of midazolam and fentanyl and after TOF ratio recovered to 1.0 were significantly lower than the baseline values in all patients (P < 0.01). CONCLUSIONS: After a single intubating dose of rocuronium, residual paralysis exists in the majority of patients undergoing laparoscopic gynecological surgeries. The pulmonary function is impaired after the surgery, even after recovery of TOF ratio to 1.0.

Perioperative tobacco interventions by Chinese anesthesiologists: practices and attitudes.

BACKGROUND: The prevalence of cigarette smoking in China is high. Surgery provides an excellent opportunity for patients to quit smoking, and anesthesiologists can play an important role in tobacco control. However, little is known about the practices, knowledge, and attitudes of Chinese anesthesiologists regarding perioperative tobacco interventions. METHODS: Chinese anesthesiologists were surveyed at a national meeting in 2009, with written questionnaires distributed to 800 practicing anesthesiologists. RESULTS: The survey response rate was 60.3%, and 10% of respondents themselves smoked cigarettes. Most (73%) of them frequently or almost always asked about smoking status; 51% advised about the health risk of tobacco use; and 60% advised patients to quit. Compared with nonsmokers, smokers were significantly less likely to advise about the health risks of smoking and quitting. A high proportion of respondents had accurate perceptions of perioperative and long-term health risks of smoking. Although most respondents agreed that advising patients to quit is the responsibility of anesthesiologists and the perioperative period is a good time to help patients quit smoking, few knew how to counsel about smoking or help patients get the help they needed to quit. Nonetheless, most of the respondents were willing to learn about perioperative interventions and spend an extra 5 min to help patients quit smoking. CONCLUSIONS: Given their adequate knowledge of health risks of smoking, strong perception of responsibilities, and willingness to participate in tobacco control, Chinese anesthesiologists are poised to play a significant role in tobacco control in China that could improve perioperative outcomes and promote long-term health.

[Perioperative hemodynamics in pheochromocytoma secreting different types of catecholamine].

OBJECTIVE: To analyze the characteristics of perioperative hemodynamics in pheochromocytoma secreting different types of catecholamine, and to discuss how to improve the hemodynamics. METHODS: The clinical data of 202 patients with pheochromocytoma who had received operation were analyzed. Three classification systems were used to divided the patients: they were, firstly, divided into high and low epinephrine secreting groups (E(high) and E(low)) according to the 24 hours urine catecholamine quantitation; secondly, into high and low norepinephrine secreting groups (NE(high) and NE(low)) according to 24-h urine norepinephrine quantitation; and thirdly, into high and low dopamine secreting groups (DA(high) and DA(low)) according to the 24 hours urine dopamine quantitation. Relationship between the characteristics of perioperative hemodynamics and catecholamine secreting types were analyzed. RESULTS: The highest preoperative systolic blood pressure values of E(high) and NE(high) groups were (201 +/- 40) mm Hg and (205 +/- 38) mm Hg, both significantly higher than those of the E(low) and NE(low) groups [(183 +/- 43) mm Hg, P = 0.003 and (181 +/- 43) mm Hg, P = 0.000]. The range of systolic blood pressure fluctuation during the operation of the E(high) group was 108 +/- 39 mm Hg, significantly larger than that of the E(low) group (91 +/- 33 mm Hg, P = 0.001). The incidence rates of persisting postoperative hypotension of the NE(high) and DA(high) groups were 23.3% (20/86) and 32.7% (17/52) respectively, both higher than those of the NE(low) and DA(low) groups [2.6% (3/116) and 4.0% (6/150) respectively, P = 0.000 and P = 0.000]. CONCLUSION: Different characteristics of perioperative hemodynamics are present in pheochromocytoma secreting different types of catecholamines. Patients with highly epinephrine secreting pheochromocytoma are apt to have larger blood fluctuation during the operation. Patients with highly norepinephrine and dopamine secreting pheochromocytoma are apt to suffer from persisting postoperative hypotension.

[Effects of melatonin on the voltage-gated delayed rectifier potassium channels of cultured hippocampal neurons of new-born rats].

OBJECTIVE: To investigate the effects of melatonin on voltage-gated delayed rectifier potassium channels. METHODS: Hippocampus neurons were obtained from newborn Wistar rat and cultured. Primary cultured for 7 to 12 days of new-born Wistar rat were selected as objectives. Patch clamp whole-cell recording technique was used on the hippocampus neurons cultured for 7 to 12 day. to record the delayed rectifier potassium current to analyze the basic electrophysiological characteristics. The effects of melatonin of the concentrations of 1 nmol/L, 10 nmol/L, 100 nmol/L, 1 mol/L, 10 mol/L, 100 mol/L, and 1 mmol/L on the amplitudes and kinetics of delayed rectifier potassium currents were investigated. RESULTS: With different voltage protocols and specific blockers of potassium channel (4-AP and TEA) a delayed rectifier potassium current that activated and inactivated slowly and had the outward rectifying characteristics (Ik) from the outward potassium currents in cultured new-born hippocampus neurons was separated. The effect of melatonin on the delayed rectifier channel was rapid, reversible and voltage-dependent Melatonin had no effect on the kinetic characteristics of the I -V curve. Melatonin increased the potassium current concentration-dependently. 1 - 100 nmol/L melatonin increased the amplitude of potassium current gradually; the effects of 1 - 100 micromol/L melatonin on the potassium current increased concentration-dependently, while the action of 1 mmol/L melatonin decreased. CONCLUSION: Melatonin reversibly increases the rectifier delayed potassium currents of the cultured hippocampus neurons of new-born rat. This may be involved in some aspects of physiological and pathological significance of potassium currents.

[Application of caffeine-halothane contracture test in the diagnosis of malignant hyperthermia].

OBJECTIVE: To explore the application of caffeine-halothane contracture test (CHCT) in the confirmation of malignant hyperthermia (MH). METHODS: One patient who underwent radical gastrectomy presented with clinical manifestations of MH during routine intravenous-inhalation anesthesia process. Isoflurane inhalation and the operation were ceased immediately and emergency management approaches such as physical cooling therapy were taken. Meanwhile, the levels of serum creatine kinase (CK), serum myoglobin, and urinary myoglobin were examined and rectus abdominis was taken and then CHCT was performed to confirm the clinical diagnosis. Total genome was extracted from the patient and then exons 2-18, 39-46, and 90-104 of ryanodine receptor 1 (RYR1) gene were screened to detect mutations using DNA sequencing technique. RESULTS: The patient was diagnosed as MH episode by clinical characteristics and postoperatively continuous elevation of the levels of CK, serum myoglobin, and urinary myoglobin (30 times higher than normal level). Despite halothane test was negative, the diagnosis of MH was verified by the positive result of caffeine test. DNA sequencing of RYR1 gene of the patient revealed c. 6724C > T (p. T 2 206M). CONCLUSION: CHCT can be used to confirm the diagnosis of MH.