Ablation of gene expression of N-methyl-D-aspartate receptor one by antisense oligonucleotides in striatal neurons in culture.

In the present study, a twenty-mer antisense oligonucleotide specific for N-methyl-D-aspartate receptor one (ANR1) was applied to striatal neurons in primary cell culture. The ANR1 was found to be specific and nontoxic. Significant reductions in expression of NR1 mRNA and proteins were resulted after a single dose of ANR1 transcripts. Interestingly, there were reductions in total NR1 proteins but two phosphorylated forms of NR1 proteins at serine 896 and 897 residues were not reduced. There was also no change in the pattern of distribution of NR1 immunoreactivity in the striatal neurons. In addition, significant reductions of NMDA-mediated peak inward current were found after application of a higher concentration of ANR1 (20-100 microM) by patch clamp recordings. The present results indicate that ANR1 is a useful agent in reducing NMDA receptor functions. The present data thus provide detailed cellular and molecular mechanisms to explain our previous findings of amelioration of motor symptoms in a rat model of Parkinson's disease. More importantly, application of ANR1 was also found to display neuroprotective effects of striatal neurons against NMDA-induced excitotoxic cell death. The findings have implications in development of new approach in prevention of cell death in neurodegenerative diseases and new treatments for these diseases.

Striatal neurons but not nigral dopaminergic neurons in neonatal primary cell culture express endogenous functional N-methyl-D-aspartate receptors.

Developmental expression of N-methyl-D-aspartate (NMDA) receptor subunits were determined and compared in striatal and nigral neurons in neonatal primary cell cultures. In striatal neurons, NR1, NR2A and NR2B mRNAs and immunoreactivity, and NR2D mRNA were found and the maximal levels of NR1 mRNA and immunoreactivity expression were found at 6 day-in-vitro (DIV). NMDA receptors found at this stage in striatal neurons are likely to contain NR1 plus NR2A, NR2B and NR2D subunits. In nigral neurons, NR1 and NR2B mRNAs and immunoreactivity, and NR2D mRNA were found and the maximal level of NR1 immunoreactivity expression was found at 10 DIV. Unlike striatal neurons, NMDA receptors found in nigral neurons are likely to contain NR1 plus NR2B and NR2D subunits only. NMDA-induced toxicity assays showed that striatal neurons were most susceptible to cell death at around 10 DIV but nigral neurons were not susceptible to NMDA-induced cell death at all stages. In addition, patch clamp analysis revealed that functional NMDA receptors could only be found in striatal neurons but not in nigral dopaminergic neurons in vitro. The present results indicate that striatal and nigral neurons are programmed to express distinct NMDA receptor subunits during their endogenous development in cell cultures. Despite dopaminergic neurons in culture display NMDA receptor subunits, functional NMDA receptors are not assembled. The present findings have demonstrated that dopaminergic neurons in vitro may behave very differently to their counterparts in vivo in terms of NMDA receptor-mediated responses. Our results also have implications in transplantations using dopaminergic neurons in vitro in treatments of Parkinson's disease.

Differential expression of N-methyl-D-aspartate receptor subunit messenger ribonucleic acids and immunoreactivity in the rat neostriatum during postnatal development.

The present study was performed to investigate the patterns of gene expression of N-methyl-D-aspartate (NMDA) receptors (NRs) in the rat neostriatum during postnatal development. Reverse transcriptase-polymerase chain reactions (RT-PCR) indicated that levels of NR1, NR2A and NR2D mRNAs reached peak levels between postnatal days 7 (PND 7) and PND 14. The levels of NR2B and NR2C mRNAs were low at PND 1 and their levels increased at PND 7 and remained high in adults. Immunofluorescence combined with image analysis revealed that the levels of NR1 immunoreactivity rose to its maximum at PND 14. In contrast, NR1 immunoreactivity rose progressively in perikarya of striatal neurons. Levels of NR2A immunoreactivity in the neostriatum were highest in adults. However, levels of NR2A immunoreactivity were higher in striatal neurons at PND 1 and PND 7. Levels of NR2B immunoreactivity were highest at PND 7. In the perikarya of striatal neurons however, the highest levels of NR2B immunoreactivity were detected at PND 14 and adult striatal neurons. In addition, double immunofluorescence revealed that the levels of NR1 immunoreactivity increased but the levels of NR2A immunoreactivity were the same in parvalbumin (PV)-positive striatal interneurons of PND 14 and adult rats. NR2B immunoreactivity was not detected in PV-positive neurons of PND 14 rats, but intense NR2B labeling was seen in PV-positive neurons of adult rats. Last but not least, in choline acetyltransferase (ChAT)-positive striatal interneurons of PND 14 and adult rats, levels of NR1 and NR2A immunoreactivity was seen to increase. Level of NR2B immunoreactivity remained the same in ChAT-positive neurons of PND 14 and adult rats. The present results indicate that there are differential patterns of expression of NR mRNAs and immunoreactivity in the neostriatum during different stages of postnatal development. Different combinations of NR have been found in different subpopulations of striatal neurons at different developmental stages. NR1, NR2A and NR2B are the major NMDA receptor subunits expressed during development. The change in patterns of expression of NR may be related to the functional maturation of neurons in the neostriatum.

Different trends in modulation of NMDAR1 and NMDAR2B gene expression in cultured cortical and hippocampal neurons after lead exposure.

Exposure to heavy metal lead (Pb(2+)) has been reported to cause problems in cognitive functions of the brain, e.g. memory loss and difficulties in mental development. N-Methyl-D-aspartate receptors (NRs) are important molecules that are known to be involved in mediation of learning and memory. In order to investigate the effects of Pb(2+) on the gene expression of NR1 and NR2B subunits in neurons, primary cell cultures of rat cortical and hippocampal neurons were employed. After treatments with different concentrations of Pb(2+) ions in culture medium (0, 5, 10, 25 and 50 microM), the cellular localization of Pb(2+) in neurons was evaluated by laser scan confocal microscopy by using a Pb(2+) ion specific fluorescence probe. In addition, the gene expression of NR1 and NR2B subunits was determined by reverse transcriptase-polymerase chain reaction, immunofluorescence and Western blotting. The results of the present study showed that both cortical and hippocampal neurons accumulated intracellular Pb(2+) in accordance with the concentrations of Pb(2+) ions present in the culture medium. After Pb(2+) treatments, levels of NR1 mRNA, immunoreactivity and protein were found to be unchanged but levels of NR2B mRNA, immunoreactivity and protein were found to be significantly increased in cortical neurons. In contrast, both NR1 and NR2B mRNAs, immunoreactivity and proteins were found to be significantly decreased in hippocampal neurons. The changes in gene expression were found to be dose dependent in accordance with the Pb(2+) concentrations. The present results indicate that Pb(2+) has a differential effect on the expression of NR1 and NR2B subunits in cortical and hippocampal neurons, respectively. It is likely that the toxic effects of Pb(2+) may cause differential damage to different types of memory that are mediated by cortical and hippocampal neurons, respectively.

Inadvertent hypothermia causes pulseless electrical activity in a patient during cervical spine surgery--a case report.

Recent studies have shown that hypothermia triples the incidence of major cardiac events. We present a happening in which a 71-year-old patient developed pulseless electrical activity (PEA) while he was undergoing cervical laminectomy for spinal stenosis in the sitting position. Thromboembolism or venous air embolism and acute myocardial infarction were respectively excluded by transesophageal echocardiography and cardiac enzymes analysis to be the causes of the cardiac event. The abnormal finding that stood out was low nasopharyngeal temperature (31 degrees C) during the procedure, which was thought to contribute to the development of the PEA episode.

Thermal symmetry of skin temperature: normative data of normal subjects in Taiwan.

BACKGROUND: The aims of this study were (a) to establish normative data of thermal symmetry (left vs. right) in normal subjects; (b) to compare the skin temperature in various regions between young and old people in Taiwan and between male and female. METHODS: The skin surface of 57 healthy volunteers (aged 24 to 80 yr) was divided into 25 areas and measured by an infrared thermography (Avionics TVS-2000, Japan). The average temperatures of these 25 regions were compared: (a) left vs. right side, (b) young (< or = 60 yr, n = 37) vs. old (> 60 yr, n = 20), and (c) male vs. female. Student's t-test was used to assess means between both groups. RESULTS: The neck carried the highest skin temperature (31.9 degrees C +/- 0.6; mean +/- SD) of the body in comparison with the toes that had the lowest one (27.5 degrees C +/- 2.0). The side-to-side temperature differences were subtle, which did not exceed 0.5 degrees C. The average skin temperature of elderly was slightly lower than that of young subjects in 11 out of 25 areas (p < 0.05), especially the distal parts of extremities. Elderly female had lower skin temperature in various truncal areas as compared with their counterpart. However, the skin temperature was higher in the distal extremity (p < 0.05). CONCLUSIONS: The thermoregulatory system is substantially symmetrical. The result of this study offered valuable normative database on skin thermal symmetry in normal population of Taiwan, and may be useful as a diagnostic aid in patients with various states of disorders associated with autonomic dysfunctions.

Hemodynamic changes caused by venous gas embolism in dogs: comparisons among air, carbon dioxide and oxygen.

BACKGROUND: The volume of a bulky venous air emboli (VAE) can be estimated based on the calibration curve generated by injections of minute amount of air into the right atrium (RA) of dogs. We speculated that in patients similar VAE calibration curves could be generated using CO2 injections. As part of pre-clinical evaluation of the usefulness of CO2 injection, the present study was designed to determine whether injection of CO2 into the RA would cause less hemodynamic changes in dogs as compared with that of air or O2. METHODS: Twenty-one anesthetized mongrel dogs were divided into 3 groups, i.e., groups air, CO2 and O2 (n = 7 each). Animals were injected a bolus of gas (air, CO2 or O2) in increasing volumes (from 0.25 to 4.0 mL/kg) into the RA via a central venous catheter at 10-min intervals. We measured the maximal changes in mean arterial pressure (MAP), pulmonary arterial pressure (PAP), central venous pressure (CVP), end-tidal CO2 (ETCO2), heart rate (HR), and mixed venous O2 saturation (SvO2). RESULTS: After venous injections, dogs receiving O2 or air showed greater decreases in MAP and ETCO2 as compared with those receiving CO2 (volume > 2.5 mL/kg; P < 0.05). The increases in PAP and CVP bore direct relation to O2 and air volume. In the CO2 group, the maximal changes in PAP and CVP were subtle as compared with the baseline (P < 0.05). There were no significant differences in HR and SvO2 among three groups. CONCLUSIONS: Injections of CO2 in increasing volumes into the RA of dogs caused less hemodynamic changes in comparison with that of air and O2.

Repeated attacks of venous air embolism during craniotomy--a case report.

Venous air embolism (VAE) is not uncommon during craniotomy, but repeated attacks of VAE during a single surgical procedure is rarely seen. We report a successful intraoperative management of repeated attacks of air embolism in a patient who sustained craniotomy for intracranial hemorrhage (ICH) in prone position. A 70-year-old male suffering from hemorrhage in the right cerebellar hemisphere with impending brainstem herniation was scheduled for craniotomy. He had history of hypertension but it was not well controlled with medical treatment. Emergent craniotomy for removal of blood clot resulting from ICH was performed. During the operation, sudden decrease of end-tidal CO2 (EtCO2) level, fall of blood pressure and increase of central venous pressure (CVP) were noted. Since air bubbles were retrieved from CVP catheter venous air embolism was highly suspected. With prompt diagnosis and proper management, we successfully improved the patient's hemodynamic status and he was discharged without any sequelae. Early detection together with aggressive treatment is the only way in the management of intraoperative venous air embolism.

Inadvertent knotting of a thoracic epidural catheter.

We report a case of corrosive injury of upper gastrointestinal and respiratory tracts scheduled for feeding jejunostomy under thoracic epidural anesthesia. An epidural catheter was inserted at the T8-T9 intervertebral space and threaded 7 cm beyond the tip of the Tuohy needle in a rostral direction. Resistance was noticed during attempts to inject the local anesthetic. As resistance could not be relieved by changing the position of the patient, kinking of the epidural catheter was suspected. Following informing the patient of the associated risks, the catheter was retrieved successfully by gentle and steady pulling. A tight double-knot of catheter was found. No neurological sequelae to the procedure were noticed.

Bilateral pulmonary edema after endoscopic sympathectomy in a patient with glucose-6-phosphate dehydrogenase deficiency.

Transaxillary endoscopic sympathectomy of thoracic ganglia (T2-T3) has recently gained wider acceptance as the treatment of choice for palmar hyperhidrosis. It requires one-lung ventilation to facilitate the surgery. One-lung ventilation, however, is not without complications, among which acute pulmonary edema has been reported. In this case report, we present a patient with palmar hyperhidrosis complicated by glucose-6-phosphate dehydrogenase (G-6-PD) deficiency, who received bilateral endoscopic sympathectomy under alternate one-lung anesthesia, and developed acute pulmonary edema immediately after recruitment of the successive collapsed lung. The effects of hypoxemia, G-6-PD deficiency and sympathectomy might all add to the development of acute pulmonary edema secondary to reexpansion of each individual lung after alternate one-lung ventilation. The possibilities of the inferred causes are herein discussed.

Chemical sympathectomy for neuropathic pain: does it work? Case report and systematic literature review.

OBJECTIVE: To determine if chemical sympathectomy successfully reduces limb neuropathic pain. DESIGN: Systematic literature review of the effectiveness of phenol or alcohol sympathectomy for extremity neuropathic pain. PATIENT: A 29-year-old female with complex regional pain syndrome of both lower extremities after back surgery who was submitted to bilateral lumbar chemical sympathectomy. SEARCH STRATEGY: The Cochrane Database of Systematic Reviews, the Cochrane Controlled Trials Register, Medline, and EMBASE were systematically searched. OUTCOME MEASURES: (1) For the patient in question: spontaneous pain, allodynia, pinprick hyperalgesia, pressure evoked pain; (2) For the literature review: meaningful versus nonmeaningful pain relief based on degree and duration (>2 weeks) of pain relief. RESULTS: (1) The case reported experienced partial temporary relief of pain primarily related to selective modulation of allodynia, but not deep pain or pinprick hyperalgesia; (2) 44% of 66 patients in 13 studies that met the authors' inclusion criteria experienced meaningful pain relief. Whereas 19% experienced no meaningful relief, for the remaining 37% of the patients no conclusions regarding duration and degree of relief could be drawn due to poor reporting of outcomes. CONCLUSIONS: Based on the case reported and systematic literature review, chemical sympathectomy seems to have at best a temporary effect, limited to cutaneous allodynia. Despite the popularity of chemical sympatholysis, only few patients and poorly defined outcomes are reported in the literature, substantiating the need for well-designed studies on the effectiveness of the procedure.

Anesthetic management of a patient with relapsing polychondritis--a case report.

Relapsing polychondritis is a rare multisystem disorder of uncertain etiology. It is characterized by recurrent and progressive destruction of both elastic and hyaline cartilages as well as connective tissue. Respiratory tract involvement is associated with high mortality and morbidity. General anesthesia may be required in these patients for tracheostomy, bronchoscopy, nasal reconstruction, aortic valve replacement, and recent tracheobronchial stenting which they usually sustain. Tracheostomy was once the most likely surgical procedure in relapsing polychondritis. However, this procedure is only effective in patients with upper subglottic involvement. In cases of extensive tracheobronchial involvement, tracheostomy is ineffective because the distant tracheal collapse below the tracheostomy is still unresolved. We would like to report a case of relapsing polychondritis with tracheobronchial involvement, who underwent an emergent tracheostomy. Tracheostomy with continuous positive airway pressure (CPAP) effectively improved her airway collapse. Herein, we also discuss the anesthetic management after review of the current literature.

Effects of glucose-free maintenance solution on plasma glucose during anesthesia in patients undergoing long neurologic surgery.

BACKGROUND: Using glucose-free solution as fluid maintenance is widely advocated during neurosurgery because of concerns about hyperglycemia aggravating cerebral ischemia. This study evaluated the alterations in plasma glucose concentrations in both adult and pediatric patients undergoing lengthy neurologic surgery, during which they were given glucose-free solutions. METHODS: This study included 154 patients (ASA class II, aged 3 months-75 years) undergoing elective neurosurgical procedures. They were divided into two groups: group A (15-75 years-of-age) and group P (3 months-14 years-of-age). Groups A (n = 126) and P (n = 28) were further divided into five subgroups, respectively, based on the duration of surgery: 5, 6, 7, 8 and 9 hours. Anesthesia was maintained with isoflurane, fentanyl and vecuronium. Blood sampling was undertaken every hour throughout surgery. RESULTS: Adult patients differed significantly in body weight (61.5 +/- 10.9 vs 25.6 +/- 14.9 kg), age (58.9 +/- 15.7 vs 7.5 +/- 4.3 years), use of preoperative beta-blocking agents (33/126 vs 1/28) and the need for blood transfusion (58/126 vs 24/28). Neither group had elevated glucose levels. Compared with pediatric patients, the incidence of intraoperative hypoglycemia was statistically higher in adult patients, with a rate that peaked in the eighth (25.9%, group A vs 0% group P) and ninth hours (27.3%, group A vs 0% group P) of surgery. There were no differences in glucose concentrations at other points in time. CONCLUSIONS: In contrast to pediatric patients, intraoperative hypoglycemia occurred more often in adult patients during prolonged neurosurgical procedures when glucose-free solution was used for fluid maintenance. Therefore, frequent determination of plasma glucose concentrations is mandatory, especially in patients undergoing long-lasting neurosurgical anesthesia.

Thoracic epidural analgesia with morphine does not prevent postthoracotomy pain syndrome: a survey of 159 patients.

BACKGROUND: This retrospective study sought to determine the incidence of postthoracotomy pain syndrome (PTPS), and whether epidural morphine for the postoperative analgesia could prevent the development of PTPS. METHODS: We reviewed the charts of 372 patients who had undergone thoracotomy. The majority underwent general anesthesia (GA) combined with thoracic epidural analgesia (TEA). Of the 372 patients, only 159 (42%) were available for interview. Patients were divided into two groups based on the duration of pain, i.e., pain group (pain > 3 months, n = 65) and pain-free group (pain < 3 months, n = 94). RESULTS: Both groups were comparable regarding sex, age, weight, height, smoking, alcohol ingestion, education, marital status, duration of surgery, and the number of patients either receiving GA plus TEA or GA alone. About 41% of the patients experienced PTPS that persisted for 21 +/- 12 mon (follow-up: 28 +/- 12 mon). Most pain was mild or moderate and was usually described as being only a discomfort. Only 6.2% suffered severe pain with shooting, aching, burning or numbness. Patients with PTPS suffered more depression and insomnia. The incidence of PTPS was not different in patients who received GA alone or GA plus TEA (39% vs. 42%). CONCLUSIONS: Epidural morphine for postoperative analgesia that continued for 3 days appeared to have no effect in the prevention of PTPS.

Postoperative pulmonary edema after cervical spine surgery--a case report.

Injury of the cervical spine may cause serious complications and neurological sequelae. Recently, a patient with C1-2 spinal cord compression developed pulmonary edema postoperatively associated with unstable hemodynamics, which might result from overzealous fluid administration in order to correct neurogenic shock during anesthesia. Therefore, early recognition and timely use of vasoconstrictors, together with judicious fluid replacement are important in the anesthetic management of patients with cervical spine injury undergoing surgery. In addition, the placement of pulmonary artery catheter is crucial for assessing the cardiac function and fluid status.

Unexpected transurethral resection of prostate syndrome complicated with acute myocardial infarction during transurethral incision procedure--a case report.

Transurethral incision (TUI) is a simple and safe procedure. We, herein, present a case undergoing transurethral incision procedure during which he developed transurethral resection of prostate syndrome (TURP syndrome) and hypothermia precipitating an acute perioperative myocardial infarction attack. The potential risk of development of TURP syndrome in settings other than TURP surgery as well as its prevention are reviewed and discussed.

Normative data of quantitative thermal and vibratory thresholds in normal subjects in Taiwan: gender and age effect.

BACKGROUND: Quantitative sensory testing has gained popularity as a tool in the diagnosis of peripheral neuropathies. This study aims to establish normative data of quantitative thermal and vibratory thresholds in normal subjects in Taiwan. In addition, we also examined the effect of age and gender differences on these thresholds. METHODS: The study included 100 healthy subjects (50 males and 50 females) who were admitted for regular physical examination. The quantitative testing of thermal, cold and vibratory sensations were performed having recourse to a Thermotest instrument applied on the right hand and foot of these subjects. Measurements included perception thresholds of warm (WT), cold (CT), heat pain, cold pain and vibration as well as a visual analog pain scale. RESULTS: Age was comparable between the sexes, but the male subjects were taller than the female subjects. A higher WT and CT in the hand, but not in the foot, were found in the male subjects in comparison with the female subjects. Heat pain threshold and cold pain threshold of both sites did not significantly differ between genders. Moreover, the groups did not differ in vibration threshold and visual analog pain scale. Young subjects (age < 30 years) showed a higher CT in the foot than the older subjects (age > 50 years). None of the above parameters were different between these two age groups. Overall, the age or height bore no significant relation to the difference between WT and CT (DDWT-CT). CONCLUSIONS: The female subjects were found to be more sensitive to warm and cold stimulation in the hand than their counterparts. These results have provided valuable normative data on sensory perceptive thresholds in Taiwanese, which are useful as a tool in the diagnosis of peripheral neuropathy.