Buccal Nerve Trunk Block Anesthetizes the Buccal Mucosa Beyond the Papilla of the Parotid Duct.

PURPOSE: The limited area of anesthesia of the buccal mucosa with concomitant conventional buccal nerve block (conventional BNB) may be involved in failed inferior alveolar nerve block (IANB). The aims of this study were to examine the extent of anesthesia by buccal nerve trunk block (BNTB) and compare the success rates of IANB with BNB. METHODS: This prospective parallel-group randomized single-blinded clinical trial included patients scheduled for removal of a mandibular third molar at the Nippon Dental University Hospital between September 2021 and March 2022. The primary predictor variable was the approach for BNB (BNTB vs conventional BNB). The primary outcome was the extent of tactile sensory loss and anesthesia of the buccal mucosa. The secondary outcomes included onset time and duration of BNBs and the success rate of the IANB with concomitant BNB for third molar extraction, assessed by the proportions of intraoperative pain perception and supplemental infiltration anesthesia. The other study variables were sex, age, and injection side. Comparisons were analyzed by Fisher's exact test or the Mann-Whitney U test. The P value was set to .05. RESULTS: A total of 38 patients (14 male, 24 female) with a mean age of 28.9 years (range, 18 to 67 years) were enrolled, with 19 patients each in the BNTB group and conventional BNB group. The effective tactile sensory loss rates at ∼5 mm above the height of the papilla of the parotid duct of the premolar and molar regions were greater following BNTB (71 and 95%, respectively) than following conventional BNB (37%; P < .01 and 58%; P < .01, respectively). The proportions of intraoperative pain perception of the BNTB group and the conventional BNB group were 10 and 42% (P = .06), respectively, and those of supplemental infiltration anesthesia were 5 and 26% (P = .18), respectively. CONCLUSIONS: BNTB provided a wider extent of anesthesia of the buccal mucosa than conventional BNB and may improve the anesthesia success of IANB for removal of mandibular third molars.

Inferior Alveolar Nerve Block Using the Anterior Technique to Anesthetize Buccal Nerve and Improve Anesthesia Success Rates for Third Molar Extraction: A Randomized Controlled Trial and Magnetic Resonance Imaging Evaluation.

PURPOSE: The lack of anesthesia to the buccal nerve and an insufficient volume of anesthetic have been reported to be responsible for failed inferior alveolar nerve blocks (IANBs) using the Halsted approach (conventional IANB). We aimed to determine the extent of anesthesia in the buccal nerve innervation area and evaluate the anesthetic efficacy of injecting a larger volume of anesthetic during IANB using the anterior approach (anterior technique) in the clinical setting and with magnetic resonance imaging (MRI) analysis. PATIENTS AND METHODS: The prospective randomized controlled trial included patients scheduled for removal of a mandibular third molar. The primary predictor variables were the approach for IANB (anterior technique vs conventional IANB) and anesthetic dose (1.8 vs 2.7 mL). The primary outcome variables were the extent of anesthesia and the anesthesia success rate, defined as completion without additional anesthesia. The secondary outcome variable was the anesthetic drug distribution related to the pterygomandibular space measured on T2-weighted MRI scans. Statistical independence of the anesthesia success rate among the primary predictor variables was tested with statistical significance set at P ≤ .05. RESULTS: A total of 108 patients and 10 volunteers were enrolled in the clinical and MRI studies, respectively. Anesthesia of the buccal nerve was evident in patients receiving the anterior technique with 2.7 mL of anesthetic. The success rate of the anterior technique with 2.7 mL of anesthetic (96%) was greater than that with 1.8 mL of anesthetic (67%; P = .0113), and increasing the dose had no effect on the efficacy of conventional IANB (78% vs 81%; P = 1.000). The MRI study showed that the anesthetic was distributed over the anterior surface of the temporalis tendon and in the pterygomandibular space after the anterior technique. CONCLUSIONS: Anesthesia of the buccal nerve using the anterior technique with 2.7 mL of anesthetic solution might contribute to increasing the success rate of anesthesia for removal of mandibular third molars.

Role of tube size and intranasal compression of the nasotracheal tube in respiratory pressure loss during nasotracheal intubation: a laboratory study.

BACKGROUND: Small nasotracheal tubes (NTTs) and intranasal compression of the NTT in the nasal cavity may contribute to increasing airway resistance. Since the effects of size, shape, and partial compression of the NTT on airway resistance have not been investigated, values of airway resistance with partial compression of preformed NTTs of various sizes were determined. METHODS: To determine the factors affecting the respiratory pressure loss during the nasotracheal intubation, physical and fluid dynamics simulations were used. The internal minor axes of NTTs in the nasal cavity of intubated patients were measured using dial calipers. In physical and fluid dynamics simulations, pressure losses through the tubular parts, compressed parts, and slip joints of NTTs with internal diameters (IDs) of 6.0, 6.5, 7.0, 7.5, and 8.0 mm were estimated under partial compression. RESULTS: The median internal minor axes of the 7.0- and 7.5-mm ID NTTs in the nasal cavity were 5.2 (4.3-5.6) mm and 6.0 (4.2-7.0) mm, respectively. With a volumetric air flow rate of 30 L/min, pressure losses through uncompressed NTTs with IDs of 6.0-, 6.5-, 7.0-, 7.5- and 8.0-mm were 651.6 ± 5.7 (6.64 ± 0.06), 453.4 ± 3.9 (4.62 ± 0.04), 336.5 ± 2.2 (3.43 ± 0.02), 225.2 ± 0.2 (2.30 ± 0.00), and 179.0 ± 1.1 Pa (1.82 ± 0.01 cmH2O), respectively; the pressure losses through the slip joints were 220.3 (2.25), 131.1 (1.33), 86.8 (0.88), 57.1 (0.58), and 36.1 Pa (0.37 cmH2O), respectively; and the pressure losses through the curvature of the NTT were 71.6 (0.73), 69.0 (0.70), 64.8 (0.66), 32.5 (0.33), and 41.6 Pa (0.42 cmH2O), respectively. A maximum compression force of 34.1 N increased the pressure losses by 82.0 (0.84), 38.0 (0.39), 23.5 (0.24), 16.6 (0.17), and 9.3 Pa (0.09 cmH2O), respectively. CONCLUSION: Pressure losses through NTTs are in inverse proportion to the tubes' IDs; greater pressure losses due to slip joints, acute bending, and partial compression of the NTT were obvious in small NTTs. Pressure losses through NTTs, especially in small NTTs, could increase the work of breathing to a greater extent than that through standard tubes; intranasal compression further increases the pressure loss.

Roles of endotracheal tubes and slip joints in respiratory pressure loss: a laboratory study.

PURPOSE: The endotracheal tube (ETT) constitutes a significant component of total airway resistance. However, a discrepancy between measured and theoretical values has been reported in airway resistance through ETTs. The causes of the discrepancy were estimated by physical and rheological simulations. METHODS: The pressure losses through total lengths of ETTs and slip joints under a volumetric flow rate of 30 L/min were measured, and the pressure losses through the tubular parts of ETTs with internal diameters (IDs) of 6.0-, 6.5-, 7.0-, 7.5-, and 8.0 mm were measured. The Reynolds number of each setting was calculated, and the pressure losses through the total length of the ETT, the tubular part, and the slip joint of each size of tube were estimated. RESULTS: The Reynolds numbers were >5000 in all sizes of ETTs. Measured pressure losses were larger in small sized ETTs than in large sized ETTs-520.9 Pascals (Pa) in 6.0-mm ID and 136.4 Pa in 8.0-mm ID tubes. The measured pressure losses through the tubular part were comparable to the predicted values. The measured pressure losses through the slip joints were larger than the predicted values, and they accounted for approximately 25-40% of total pressure losses of the ETTs. CONCLUSION: Especially in small sized tubes, the pressure loss through the slip joint accounts for a large percentage of the total pressure loss through the ETT. The pressure loss through the slip joint may play a role in the discrepancy between measured and theoretical pressure losses through ETTs.

Possible association between successful intubation via the right nostril and anatomical variations of the nasopharynx during nasotracheal intubation: a multiplanar imaging study.

PURPOSE: Most reported cases of nasopharyngeal laceration following impingement during nasotracheal intubation involved tube insertion via the right nostril. We postulated that recesses on the posterior wall of the nasopharynx might be associated with tube impingement. Using multiplanar imaging and clinical statistics, we evaluated whether anatomical variations in the recesses are related to successful intubation via the right nostril. METHODS: Using multiplanar computed tomography (CT) images of 97 patients, we investigated the locations of recesses relative to the mid-sagittal plane, nasal floor plane and posterior end of the nasal septum, and their shapes. Incidents of impingement of the tube during nasotracheal intubation and the shapes of the fossa of Rosenmüller on CT images were retrospectively evaluated in 170 patients. RESULTS: Eustachian tube orifices were located approximately 10 mm laterally from the sagittal plane, and approximately 10 mm above the nasal floor plane. The fossa of Rosenmüller was vertically elongated and located 7 mm laterally from the mid-sagittal plane. Pharyngeal bursae were found in 15 % of the subjects. Patients with failed insertion via the right nostril due to impingement frequently had a wide opening of the fossa of Rosenmüller. CONCLUSIONS: Successful intubation via the right nostril is related to the anatomy of structures on the posterior nasopharyngeal wall, particularly recesses located close to the path of nasotracheal tube insertion. Nasopharyngeal anatomical variations should be considered when one notices any resistance to advancement of the tube into the nasopharynx during nasotracheal intubation.

Periodontal pathogens participate in synovitis in patients with rheumatoid arthritis in clinical remission: a retrospective case-control study.

OBJECTIVE: The objective of this study was to investigate the role of periodontal pathogens in RA in remission. METHODS: Twenty-one patients with active RA and 70 patients in clinical remission, including 48 patients with synovitis [US power Doppler (USPD)(+) group] and 22 patients without synovitis [USPD(-) group] were clinically assessed by US. CRP, ESR, haemoglobin, MMP-3, RF and ACPA were measured. Antibody titres against four types of periodontal pathogen [Aggregatibacter actinomycetemcomitans, Eikenella corrodens (Ec), Porphyromonas gingivalis and Prevotella intermedia (Pi)] were analysed using ELISA. RESULTS: Musculoskeletal US examination showed that 68.6% of patients with RA in clinical remission exhibited synovitis. CRP, ESR, haemoglobin, MMP-3 and RF levels in both the USPD(+) and USPD(-) groups were clearly lower compared with the RA group in non-remission. The IgG serum antibody titre against Ec in the non-remission RA(+) group was significantly greater than that in the USPD(+) group, and the IgG antibody titre against Pi in the non-remission RA and USPD(+) groups was greater than in the USPD(-) group. CONCLUSION: More than half of RA patients in remission showed persistent synovitis. This synovitis may be associated with periodontal disease-causing Pi. Thus, treating periodontal disease should also be considered in order to achieve more profound remission of RA.

Fatal pulmonary embolism following spinal surgery in a patient with permanent inferior vena cava filter placement.

It has been proven that the use of an inferior vena cava filter (IVCF) is effective in decreasing the incidence of pulmonary embolism (PE) in high-risk spinal surgery patients. A case of fatal PE after spinal surgery in a 78-year-old woman who had a history of pulmonary hypertension due to peripheral PE treated with a permanent IVCF and anticoagulant therapy for 3 years is reported. The patient had experienced an episode of recurrent PE during the withdrawal of anticoagulants, but she had uneventfully undergone two orthopedic surgeries with a preoperative unfractionated heparin infusion instead of oral warfarin. Three months after the second operation, she underwent posterior lumbar spinal fusion. The following morning, she suddenly complained of chest discomfort and dyspnea with SpO(2) 78 %. An electrocardiogram showed a right bundle branch block. Then, 30 min later, she suddenly lost consciousness, and her carotid pulse was not palpable. The patient died 2 h and 30 min after onset. Acute PE probably occurred because of a massive thrombus above the IVCF. This case suggests that the efficacy of long- term use of a permanent IVCF is limited in cases when anticoagulants must be withdrawn, such as for orthopedic surgery.

Antinociceptive action of carbamazepine on thermal hypersensitive pain at spinal level in a rat model of adjuvant-induced chronic inflammation.

PURPOSE: Systemic carbamazepine, a voltage-gated sodium channel blocker, has been reported to dose-dependently reduce inflammatory hyperalgesia. However, the antinociceptive effects of carbamazepine on the spinal cord in inflammatory conditions are unclear. The aim of the present study was to evaluate the antinociceptive effects of carbamazepine on the spinal cord in a chronic inflammatory condition. METHODS: In Sprague-Dawley rats, a chronic inflammatory condition was induced by complete Freund's adjuvant (CFA) inoculation into the tail. Tail flick (TF) latencies were measured following intraperitoneal carbamazepine, or intrathecal carbamazepine or tetrodotoxin injection in intact rats and in the chronic inflammatory rats. From the values of TF latency at 60 min after drug injection, the effective dose required to produce 50% response (ED(50)) of each drug was derived. RESULTS: Carbamazepine attenuated thermal responses with both systemic and intrathecal administration. The effect was more evident in rats with chronic inflammation than in intact rats; the ED(50s) of intraperitoneal carbamazepine in intact and inflamed rats were 12.39 and 1.54 mg/kg, and those of intrathecal carbamazepine were 0.311 and 0.048 nmol, respectively. Intrathecal tetrodotoxin also clearly inhibited the response, with ED(50s) of 1.006 pmol in intact rats and 0.310 pmol in inflamed rats. The relative potencies of intrathecal carbamazepine versus tetrodotoxin for inhibition were approximately 1:150-1:300 in intact and inflamed rats. CONCLUSION: These results indicate that the inhibition of voltage-gated sodium channels, at least tetrodotoxin-sensitive channels, may contribute to the antinociceptive effect of carbamazepine on CFA-induced inflammatory pain, since lower doses of intrathecal carbamazepine and tetrodotoxin attenuated thermal responses to a greater extent in inflamed rats than in intact rats.

Tracheal intubation in a patient with undetectable tracheal narrowing on chest radiography.

We report here a 59-year-old man with a saber-sheath tracheal narrowing who was scheduled to undergo pharyngeal tumor resection under general anesthesia. The tracheal narrowing was not clearly detected by chest radiography during the preoperative examination, but it was visible on axial computed tomography (CT) images taken earlier for diagnostic purposes. Following fiber optic examination of the narrowed segment with the patient under anesthesia, the tube was inserted into the trachea using an Airway Scope. The tube was deliberately advanced into the trachea and was able to pass through the stenosis without any resistance. On postoperative radiological analysis, three-dimensional reconstruction of the trachea and virtual bronchoscopic images revealed a saber-sheath type tracheomalacia located from below the cricoid cartilage to the carina. The membranous wall had a normal width. This case indicates that chest radiographs may occasionally be inadequate for evaluating asymptomatic patients with tracheomalacia. If CT images have been taken for diagnostic purposes, they should be examined together with the chest radiograph. Digital chest radiography with edge enhancement may become a useful tool in the preoperative detection and evaluation of undetectable tracheal narrowing on conventional chest films.

[Application of video laryngoscope for vocal cord synechiotomy in a patient with recurrent laryngeal nerve paralysis].

Vocal cord synechia causes respiratory disturbance and severe pneumonia. A 63-year-old woman with recurrent laryngeal nerve paralysis caused by translaryngeal intubation after resection of acoustic tumor and by thyroid surgery in her history and progressive dyspnea, had received vocal cord synechiotomy under general anesthesia. Preoperative endoscopic examination revealed edematous larynx, immobility of left unilateral vocal fold, insufficient mobility of right vocal fold, left arytenoid cartilage dislocation and a posterior glottic adhesion. Anesthesia was induced by propofol administration, and a muscle relaxant was administered following confirmation of effective face mask ventilation. Trachea was cannulated immediately after incision of the scar under indirect video laryngoscopy. Vocal cord synechiotomy was completed without any respiratory complication. The case indicated that recurrent laryngeal nerve paralysis has a potential for vocal cord synechia and difficulty of tracheal intubation, and visibility of the surgical field among anesthesiologists and surgeons by indirect video laryngoscopy for vocal cord synechiotomy contributes to establish prompt surgical manipulation and tracheal intubation as to vocal cord synechiotomy.

Difficult laryngoscopy caused by massive mandibular tori.

Mandibular tori, defined as bony protuberances located along the lingual aspect of the mandible, are a possible cause of difficult intubation. We describe a case of mandibular tori that resulted in difficult intubation. A 62-year-old woman who had speech problems was diagnosed with mandibular tori, and was scheduled for surgical resection. On physical assessment, the patient had a class II Mallampati view and bilateral mandibular tori. Preoperative computed tomography images demonstrated that the bilateral mandibular tori arose from the lingual aspects of the second incisor to the first molar regions of the mandibular corpus, and occupied the floor of the mouth. In the operating room, anesthesia was induced with remifentanil and propofol. After complete paralysis was achieved, laryngoscopy was attempted several times with Macintosh blades. The massive tori prevented insertion of the tip of the blade into the oropharynx, and neither the epiglottis nor the arytenoids could be visualized, i.e., Cormack and Lehane grade IV. Blind nasotracheal intubation was successful and the surgery proceeded uneventfully. The anesthesiologist should examine any space-occupying lesion of the oral floor and should be vigilant for speech problems in order to detect mandibular tori that might impede intubation.

Three-dimensional CT image analysis of a tracheal bronchus in a patient undergoing cardiac surgery with one-lung ventilation.

The incidence of a tracheal bronchus--that is, a congenitally abnormal bronchus originating from the trachea or main bronchi--is 0.1%-2%. Serious hypoxia and atelectasis can develop in such patients with intubation and one-lung ventilation. We experienced a remarkable decrease in peripheral oxygen saturation (SpO2) and a rise in airway pressure during placement of a double-lumen endobronchial tube in a patient with patent ductus arteriosus and tracheal bronchus. Substitution of the double-lumen tube with a bronchial blocker tube provided secure isolation of the lung intraoperatively. A type I tracheal bronchus and segmental tracheal stenosis were identified on postoperative three-dimensional (3D) computed tomographic (CT) images. Preoperative examination of chest X-rays, CT images, and preoperative tracheal 3D images should preempt such complications and assist in securing safe and optimal one-lung ventilation.

Suppression of the descending inhibitory pathway by continuous thoracic intrathecal lidocaine infusion reduces the thermal threshold of the tail-flick response in rats.

PURPOSE: For the suppression of descending inhibitory pathways in animals, single-dose lidocaine blockade is reversible and causes less damage than chronic spinal cord injury, decerebration, and cold blockade of the spinal cord. However, single-dose blockade has a variable onset and is relatively short-lived. To surmount these disadvantages, we devised a continuous thoracic intrathecal lidocaine infusion and evaluated its effects in rats. METHODS: Rats were administered continuous intrathecal infusions of 0, 0.25%, 0.5%, and 1% lidocaine at 10 &gml.h(-1) following a 10-&gml bolus. The effects of the continuous thoracic blockade on tail-flick (TF) latency (estimated by the percent maximum possible effect [%MPE]) and on the release of neurotransmitters in the cerebrospinal fluid (CSF) were evaluated. RESULTS: Continuous thoracic blockade with 0.5% and 1% lidocaine infusion reversibly shortened TF latency (%MPE, -22.0 +/- 11.0 % and -21.2 +/- 4.6 %, respectively, versus baseline; P < 0.05) during drug infusion. Compared with normal saline, thoracic intrathecal infusion of lidocaine significantly lowered norepinephrine and serotonin concentrations in the CSF at 1 h of infusion (P = 0.02 for both). CONCLUSION: Continuous thoracic blockade by local anesthetic resulted in reversible suppression of descending inhibitory pathways for varying durations. Such blockade may provide further information regarding nociceptive transmission and the mechanisms of antinociception in animals.

Transient lower limb pain following accidental thoracic subarachnoid insertion of an epidural catheter.

Transient sensory disturbances, including dysesthesia or neurologic deficits in the lower extremities or buttocks have been described as complications of neuraxial anesthesia. We report a case of transient lower limb pain following the accidental placement of an epidural catheter into the thoracic subarachnoid space. A 31-year-old woman was scheduled to undergo laparoscopic myomectomy. An epidural catheter was accidentally inserted subarachnoid at the T12-L1 intervertebral space with a 2-ml test dose of 2% lidocaine, and was promptly removed. Fulgurant pain and allodynia extending over the L2-5 areas of the left lower limb and buttock started immediately postoperatively. We treated the persistent pain in our patient with epidural infusion of local anesthetics and steroids during her hospital stay, and with carbamazepine and a tricyclic antidepressant after her discharge from the hospital. All signs of allodynia had disappeared on postoperative day 25. Sagittal and axial T2-weighted magnetic resonance imaging (MRI) at the Th12 level revealed a small high-intensity area without mass effect in the ipsilateral dorsal column. The patient's clinical course and MRI diagnosis suggested the inhibition of descending inhibitory pathways resulting from a lesion of the spinal cord as the possible etiology of the transient lower limb pain and allodynia.

The effect of Sub-MAC anesthesia and the radiation setting on repeated tail flick testing in rats.

The tail flick (TF) response is regarded as a spinal reflex that is influenced by supraspinal structures. The TF test using radiant heat is the most common way to assess pain perception; however, there are few reports dealing with the heat source's properties and score consistency. This study examined the usefulness of light anesthesia for suppressing supraspinal signals and the effects of radiant heat on skin temperature during TF testing. The fluctuations of TF latency over one hour were evaluated while the rats were given oxygen and 0%, 0.5%, 1.0%, or 1.5% isoflurane. The stimulator's infrared radiant (IR) power flux was measured over time, and the tail skin surface temperature was predicted using a non-linear regression equation. TF latencies were measured at various heat source intensities, and response temperatures were estimated. Inhalation anesthesia suppressed the TF reflex according to the inspiratory concentration of the volatile anesthetic. IR power fluxes reached constant power 2.5 s after the stimulator was turned on, and the predicted skin temperature depended on the maximum IR power flux of the IR intensity and the radiation time. One percent isoflurane inhalation and an IR20 heat intensity (which was 161.5 mW/cm(2) and resulted in a skin temperature of 65 degrees C after 10 s of radiation) provided reliable TF latencies on repeated TF testing. Given these results, it can be concluded that the stimulator setting influenced TF latency, and that the inhalation of light anesthesia provided consistent scores on repeated TF testing.

[Compression of a nasotracheal tube in the nasal cavity of a patient with craniofacial fibrous dysplasia].

A 42-year-old woman with craniofacial fibrous dysplasia underwent osteoplasty of maxillary and mandibular bone. Preoperative CT images showed osteosclerosis and ground glass appearance of the right side of the skull including the orbit, temporal bone, paranasal sinus, and maxillary and mandibular bones, as well as hypertrophy of the nasal septum. Inhalation anesthesia was induced and 8.0-mmID polyvinyl chloride endotracheal tube was inserted via the left nostril with slight resistance. At emergence, a 10-Fr suction catheter could not be passed throgh the tube but an 8-Fr nasogastric tube could be passed. A part of the tube positioned in the nasal cavity was apparently compressed. Preoperative examination of the nasal cavity and nasal septum using CT or MRI may be desirable for nasotracheal intubation in the patients with craniofacial tumor, and the application of a spiral reinforced endotracheal tube may contribute to prevent such cases of airway obstruction in the nasal cavity.

Thermophysical Properties of Thermosoftening Nasotracheal Tubes.

Thermosoftening treatment of polyvinyl chloride (PVC) nasotracheal tubes (NTTs) can reduce the incidence and amount of epistaxis during nasotracheal intubation. The optimal thermal setting for thermosoftening treatment of NTTs without burn injury was investigated. Two composite types of PVC NTTs were used. Following withdrawal of the PVC NTTs from a bottle of water at 45 or 60°C, the changes in the surface temperature of the NTTs were measured by infrared thermography. Hardness of the NTTs at 25, 30, 35, and 40°C was measured. The incidence of epistaxis during nasotracheal intubation using thermosoftened NTTs was evaluated retrospectively. The surface temperature of both PVC NTTs dipped in 45 and 60°C water decreased to below body temperature 30 seconds after withdrawing them from the bottles. Although thermosoftening treatment proportionally decreased the hardness of both types of NTTs, the degrees differed according to their composition. When avoiding impingement of the NTT on the posterior wall of the nasopharynx, the incidence of mild and moderate epistaxis was 2.3%. Flexibility of PVC NTTs could be obtained by thermosoftening treatment at 60°C without burn injury. Thermosoftening treatment of PVC NTTs may be useful to avoid epistaxis during nasotracheal intubation.

[Central hypotensive effect involving neurotransmitters of long-term administration of taurine to stroke-prone spontaneously hypertensive rat].

BACKGROUND: Taurine is an inhibitory neurotransmitter or neuromodulator that reduces blood pressure when systemically or centrally administered. We studied the central hypotensive effects of long-term oral taurine administration. METHODS: Arterial blood pressure was measured after delivering an intracisternal injection of 100 mg x 20 microl(-1) or 200 microg x 20microl(-1) of taurine in normal saline, or 20 micro1 normal saline to anesthetized Sprague-Dawley rats. Drinking water containing 3% taurine was administered to stroke-prone spontaneously hypertensive rats (SHRSP) from the age of 4 weeks. Amino acids and monoamine neurotransmitters in the cerebrospinal fluid were measured at 8, 12, 16, 18 weeks of age in taurine treated SHRSP and normotensive Wistar Kyoto rats (WKY) and in untreated SHRSP using high performance liquid chromatography. RESULTS: Intracisternal injections of taurine caused a dose dependent decrease in arterial blood pressure. Although concentrations of taurine decreased in treated SHRSP rats in an age-related manner, the drug persistently suppressed the development of hypertension. The values of excitatory amino acids and GABA, norepinephrine, NMN, dopamine metabolites, serotonin and its metabolite were lower in taurine-treated SHRSP than those in untreated SHRSP. CONCLUSIONS: Taurine reduces blood pressure through not only direct inhibition of the cardiovascular center in the medulla, but also by reducing brain monoamine concentrations.

[How much should be done for better thromboprophyraxis?].

How much should be done for better managements of the perioperative thromboprophylaxis? In Japan, the guideline for prevention of venous thromboembolism (VTE) was established for the first time in February, 2004. Our academic medical center formed a committee for prevention of thrombosis for all departments using operating rooms in October, 2002 and began to make the database of symptomatic pulmonary thromboembolism (PTE). From the end of September, 2003, we asked the surgeons to indicate the PTE risk grades when ordering surgical operations. The prevention team of VTE prepared VTE risk tables and recommended prevention methods for perioperative period. If surgeons did not choose prevention methods, the team took the consultation. Also, we made a manual how to make emergency calls and a flow chart for the diagnosis and therapy cooperating with cardiologists and anesthesiologists. We founded another meeting of Kinki Clinical Thrombosis Research Association for the study and education. We assessed the incidence of symptomatic PTE every year. The incidences of symptomatic PTE were 14 of 4101 (0.34%) in the first year, 2 of 3796 (0.053%) in the second year; 2 of 4002 cases (0.049%) in the third year under general anesthesia, respectively. Cases of fatal PTE were 2 (0.34%), 1 (0.049%) and 0 (0%), respectively. The multidisciplinary thromboprophylaxis effort that we had adopted was very important to prevent aggravation of VTE.

[Alteration of neurotransmitters in the cerebrospinal fluid in SHRSP rats due to long-term administration of clonidine].

BACKGROUND: Clonidine, an alpha2-adrenoreceptor and imidazoline L receptor agonist, is commonly used in the treatment of hypertension. We evaluated the central hypotensive effect of long-term oral administration of clonidine. METHODS: Clonidine was administered to stroke-prone spontaneously hypertensive rats (SHRSP) of four to twenty weeks of age. Cerebrospinal fluid (CSF) was collected via the cisterna magna every two weeks, from eight weeks of age, from clonidine treated SHRSPs, age-matched normotensive Wistar Kyoto (WKY) rats and un-treated SHRSPs. Amino acid neurotransmitters and monoamine neurotransmitters in the samples were measured by high performance liquid chromatography with electro-chemical detectors. RESULTS: The levels of norepinephrine, dopamine and serotonin were significantly higher, while taorine was significantly lower in the SHRSPs than in WKY rats. Long-term clonidine administration decreased the levels of norepinephrine, dopamine, serotonin, GABA and taurine. The levels of excitatory amino acids, however, were unaffected by clonidine administration. The levels of metabolites of norepinephrine increased, but those of dopamine and serotonin decreased. CONCLUSIONS: These results suggest that the presynaptic inhibition of norepinephrine release from norepinephrine neurons, accompanied by postsynaptic inhibition of excitatory and inhibitory neurons modulate clonidine-induced hypotension.