Enhanced structural connectivity within the motor loop in professional boxers prior to a match.

Professional boxers train to reduce their body mass before a match to refine their body movements. To test the hypothesis that the well-defined movements of boxers are represented within the motor loop (cortico-striatal circuit), we first elucidated the brain structure and functional connectivity specific to boxers and then investigated plasticity in relation to boxing matches. We recruited 21 male boxers 1 month before a match (Time1) and compared them to 22 age-, sex-, and body mass index (BMI)-matched controls. Boxers were longitudinally followed up within 1 week prior to the match (Time2) and 1 month after the match (Time3). The BMIs of boxers significantly decreased at Time2 compared with those at Time1 and Time3. Compared to controls, boxers presented significantly higher gray matter volume in the left putamen, a critical region representing motor skill training. Boxers presented significantly higher functional connectivity than controls between the left primary motor cortex (M1) and left putamen, which is an essential region for establishing well-defined movements. Boxers also showed significantly higher structural connectivity in the same region within the motor loop from Time1 to Time2 than during other periods, which may represent the refined movements of their body induced by training for the match.

Fabrication of White Light-emitting Electrochemical Cells with Stable Emission from Exciplexes.

The authors present an approach for fabricating stable white light emission from polymer light-emitting electrochemical cells (PLECs) having an active layer which consists of blue-fluorescent poly(9,9-di-n-dodecylfluorenyl-2,7-diyl) (PFD) and π-conjugated triphenylamine molecules. This white light emission originates from exciplexes formed between PFD and amines in electronically excited states. A device containing PFD, 4,4',4''-tris[2-naphthyl(phenyl)amino]triphenylamine (2-TNATA), Poly(ethylene oxide) and K2CF3SO3 showed white light emission with Commission internationale de l'éclairage (CIE) coordinates of (0.33, 0.43) and a Color Rendering Index (CRI) of Ra = 73 at an applied voltage of 3.5 V. Constant voltage measurements showed that the CIE coordinates of (0.27, 0.37), Ra of 67, and the emission color observed immediately after application of a voltage of 5 V were nearly unchanged and stable after 300 sec.

Influence of atropine on the dose requirements of propofol in humans.

OBJECTIVE: The purpose of this study was to evaluate the effect of atropine on the dose requirement of propofol for induction of anesthesia and propofol concentrations during continuous infusion. METHODS: Study 1: Forty patients were randomly allocated to the control or atropine groups. Induction of anesthesia commenced 3 min following the administration of 0.9% saline or atropine (0.01 mg kg(-1)), using a Diprifuser set to achieve propofol concentration of 6.0 microg mL(-1). The primary end point was the propofol dose per kg at the moment of loss of response to a command. Study 2: Fifteen patients undergoing elective surgery were enrolled. Propofol was administered to all subjects via target-controlled infusion to achieve a propofol concentration at 2.0 microg mL(-1) after intubation. Before and after administration of atropine (0.01 mg kg(-1)), cardiac output (CO) was measured using indocyanine green as an indicator and blood propofol concentration was determined using high-performance liquid chromatography. RESULTS: Study 1: The propofol dose for each group was 2.22+/-0.21 mg kg(-1) for control group and 2.45+/-0.28 mg kg(-1) for atropine, respectively (p=0.014). Study 2: After the administration of atropine, CO was significantly increased from 4.28+/-0.83 to 5.76+/-1.55 l min(-1) (p<0.0001). Propofol concentration was significantly decreased from 2.12+/-0.28 to 1.69+/-0.27 microg mL(-1) (p<0.0001). CONCLUSIONS: Following the administration of atropine, the propofol requirements for the induction of anesthesia were increased and propofol concentrations were decreased during continuous infusion by the administration of atropine.

The effect of positive end-expiratory pressure ventilation on propofol concentrations during general anesthesia in humans.

The present study investigated the effects of positive end-expiratory pressure (PEEP) on propofol concentrations in humans. Eleven patients undergoing elective surgery were enrolled in this study. Anesthesia was induced with propofol, then maintained using 60% nitrous oxide in oxygen, fentanyl 10-20 microg/kg and continuous infusion of propofol. Vecuronium was used to facilitate the artificial ventilation of the lungs. Propofol was administered to all subjects via target-controlled infusion to achieve a propofol concentration of 6.0 microg/mL at intubation and 2.0 microg/mL after intubation. Before, during and after PEEP level of 10 cmH(2)O, cardiac output (CO) and effective liver blood flow (LBF) was measured using indocyanine green as an indicator and blood propofol concentration was determined using high-performance liquid chromatography. Data are expressed as median and range. After PEEP of 10 cmH(2)O was applied, CO and effective LBF was significantly decreased from 5.5 (3.8-6.8) L/min to 4.5 (3.2-5.8) L/min (P < 0.05), 0.78 (0.65-1.21) L/min to 0.65 (0.50-0.89) L/min (P < 0.05), respectively. Propofol concentration was significantly increased from 2.21 (1.46-2.63) microg/mL to 2.45(1.79-2.89) microg/mL (P < 0.05). These data indicate that propofol concentrations can be increased by PEEP, suggesting the possibility of overdosing following PEEP.

Disposition and pharmacodynamics of propofol during isovolaemic haemorrhage followed by crystalloid resuscitation in humans.

AIMS: The purpose of this study was to estimate the changes in unbound propofol concentration and pharmacodynamics of propofol during isovolaemic haemorrhage followed by crystalloid resuscitation. METHODS: Ten patients undergoing measure elective surgery were enrolled in this study. Anaesthesia was maintained by 60% nitrous oxide in oxygen, fentanyl 10-20 microg kg-1 and an infusion of propofol at 8 mg kg-1 h-1 until the end of the operation. Radial arterial samples were collected for measurement of propofol concentration just before the start of the operation, and at the point when blood loss was >10 ml kg-1, 20 ml kg-1 and 30 ml kg-1. Cardiac output (CO), haemoglobin values and plasma concentrations of albumin were also determined. Patients were resuscitated with lactated Ringer's solution to maintain a mean arterial blood pressure (+/-20% of prehaemorrhage). Bispectral index (BIS) was measured continuously. RESULTS: Mean blood pressure, heart rate and CO were well maintained during the operation in all patients. Haemoglobin values and plasma albumin concentrations decreased significantly during surgery. There were no significant differences in total propofol concentrations across the time points. The unbound propofol concentration was increased from 0.10+/-0.040 microg ml-1 to 0.17+/-0.041 microg ml-1 after the haemorrhage of 30 ml kg-1 (P<0.05). BIS was significantly decreased from 47+/-5.9 to 39+/-3.7 (P<0.05) after the haemorrhage of 30 ml kg-1. CONCLUSIONS: The hypnotic potency of propofol is increased during isovolaemic haemorrhage in crystalloid resuscitated patients even if CO is maintained.

The effect of gynecologic laparoscopy on propofol concentrations administered by the target-controlled infusion system.

The purpose of this study was to assess the effect of gynecologic laparoscopy on propofol concentrations administered by the target-controlled infusion (TCI) system. Thirteen patients undergoing gynecologic laparoscopy (intraabdominal pressure of 10 mmHg) were enrolled in this study. Anesthesia was induced with vecuronium 0.1 mg.kg(-1) and propofol, then maintained by 60% nitrous oxide and sevoflurane in oxygen and a constant infusion of propofol. Propofol was administered to all subjects by means of a target-controlled infusion to achieve propofol plasma concentration at 6.0 microg.ml(-1) at intubation and 2.0 microg.ml(-1) after intubation. Before and during laparoscopy, plasma propofol concentration was determined using high-performance liquid chromatograhy. Cardiac output (CO) and effective liver blood flow (LBF) were also measured using indocyanine green as an indicator. Before and during pneumoperitoneum, there were no significant differences in propofol concentrations between each point. Propofol concentrations were well achieved to predicted concentrations administered by the TCI system during gynecologic laparoscopy under propofol and sevoflurane anesthesia.

Influence of landiolol on the dose requirement of propofol for induction of anesthesia.

It was reported that the pharmacokinetics of propofol was influenced by cardiac output (CO). The purpose of this study was to evaluate the effect of landiolol (short-acting beta-1-adrenergic blocker) on the dose requirement of propofol for induction of anesthesia. Forty patients were randomly allocated to the control and landiolol group. Induction of anesthesia commenced 10 min after the infusion of 0.9% saline or landiolol, using a Diprifusor set to achieve propofol plasma concentration of 6.0 microg/mL. Induction of anesthesia was defined as the first lack of response to command. Propofol dose was 2.22+/- 0.21 mg/kg for the control group and 1.79+/- 0.28 mg/kg for the landiolol group (P<0.0001). The quantity of propofol required for the induction of anesthesia was reduced by the administration of landiolol.

A dopamine infusion decreases propofol concentration during epidural blockade under general anesthesia.

PURPOSE: It is common clinical practice to use dopamine to manage the reduction in blood pressure accompanying epidural blockade. As propofol is a high-clearance drug, propofol concentrations can be influenced by cardiac output (CO). The purpose of the present study was to investigate the effects of dopamine infusions on propofol concentrations administered by a target-controlled infusion system during epidural block under general anesthesia. METHODS: 12 patients undergoing abdominal surgery were enrolled in this study. Anesthesia was induced with propofol and vecuronium 0.1 mg.kg(-1), and maintained using 67% nitrous oxide, sevoflurane in oxygen and constant infusion of propofol. Propofol was administered to all subjects via target-controlled infusion to achieve a propofol concentration at 6.0 microg.mL(-1) at intubation and 2.0 microg.mL(-1) after intubation. Before and after the administration of 10 mL of 1.5% mepivacaine from the epidural catheter and dopamine infusion at 5 microg.kg(-1).min(-1), CO and effective liver blood flow (LBF) were measured using indocyanine green. Blood propofol concentration was also determined using high-performance liquid chromatography. RESULTS: At one hour after epidural block and dopamine infusion, CO was significantly increased from 4.30 +/- 1.07 L.min(-1) to 5.82 +/- 0.98 L.min(-1) (P < 0.0001), and effective LBF was increased 0.75 +/- 0.17 L.min(-1) to 0.96 +/- 0.18 L.min(-1) (P < 0.0001). Propofol concentration was significantly decreased from 2.13 +/- 0.24 microg.mL(-1) to 1.59 +/- 0.29 microg.mL(-1) (P < 0.0001). CONCLUSIONS: Propofol concentrations decrease with an increase in CO, suggesting the possibility of inadequate anesthetic depth following catecholamine infusion during propofol anesthesia.

Percutaneous radiofrequency lumbar facet rhizotomy guided by computed tomography fluoroscopy.

X-ray fluoroscopy-guided percutaneous radiofrequency facet rhizotomy is used to treat chronic low back pain. The traditional fluoroscopic approach to the medial branch of the posterior rami, however, is associated with a small incidence of complications. We describe a new method for radiofrequency lumbar facet rhizotomy in which computed tomography (CT) fluoroscopy is used to guide needle placement. Three patients with chronic intractable low back pain underwent CT fluoroscopy-guided percutaneous facet rhizotomy. After the safest and shortest route to the target site was determined on the CT image, the needle was advanced along the predetermined route under real-time CT fluoroscopy. When the needle tip was located at the target site, electrical stimulation was applied to verify proper electrode placement. After confirming the clinical effect and lack of complications under test block with a local anesthetic, denervation was performed using radiofrequency current. Pain scores of all patients were reduced after the procedure without any complications such as paralysis or neuritic pain. None of the patients complained of severe discomfort during the procedure. CT fluoroscopy-guided percutaneous lumbar facet rhizotomy appears to be safe, fast, and effective for patients with lumbar facet pain.

Human kidneys play an important role in the elimination of propofol.

BACKGROUND: Extrahepatic clearance of propofol has been suggested because its total body clearance exceeds hepatic blood flow. However, it remains uncertain which organs are involved in the extrahepatic clearance of propofol. In vitro studies suggest that the kidneys contribute to the clearance of this drug. The purpose of this study was to confirm whether human kidneys participate in propofol disposition in vivo. METHODS: Ten patients scheduled to undergo nephrectomy were enrolled in this study. Renal blood flow was measured using para-aminohippurate. Anesthesia was induced with vecuronium (0.1 mg/kg) and propofol (2 mg/kg) and then maintained with nitrous oxide (60%), sevoflurane (1 approximately 2%) in oxygen, and an infusion of propofol (2 mg . kg . h). Radial arterial blood for propofol and para-aminohippurate analysis was collected from a cannula inserted in the radial artery. The renal venous sample and the radial arterial sample were obtained at the same time after the steady state of propofol was established. RESULTS: The renal extraction ratio of propofol was 0.58 +/- 0.15 (mean +/- SD). The renal clearance of propofol was 0.41 +/- 0.15 l/min (mean +/- SD), or 27 +/- 9.9% (mean +/- SD) of total body clearance. CONCLUSION: Human kidneys play an important role in the elimination of propofol.

Plasma concentration for optimal sedation and total body clearance of propofol in patients after esophagectomy.

The present study investigated plasma propofol concentration for optimal sedation and total body clearance in patients who required sedation for mechanical ventilation after esophagectomy. Seven patients after esophagectomy were enrolled in this study. Plasma propofol concentrations were measured with high performance liquid chromatography. Total body clearance was calculated from the steady-state concentration. The infusion rate of propofol for achieving the sedation score of level 3 (drowsy, responds to verbal stimulation) was 1.74 +/- 0.82 mg kg(-1) h(-1) (mean +/- SD, n = 7) when the plasma propofol concentration and the total body clearance were 0.85 +/- 0.24 microg ml(-1) and 1.83 +/- 0.54 l min(-1) (mean +/- SD, n =7), respectively.

[Postoperative laryngeal edema presumably due to hypoalbuminemia causing acute airway obstruction after extubation in a patient after nephrectomy].

We report here a case of upper airway obstruction occurring after extubation in a 55-yr-old 60 kg man after elective nephrectomy. Anesthesia was maintained with O2 (33%), N2O, sevoflurane (1.5-2%), and propofol infusion (2 mg x kg(-1) x hr(-1)). Blood loss was 1,965 ml, part of which was substituted by blood transfusion and albumin infusion. After surgery, the patient recovered uneventfully and could be extubated shortly. Twenty minutes after extubation, he developed dyspnea progressively with stridor and became cyanotic despite the use of oxygen mask and assisted ventilation. Oxygen saturation decreased gradually, and bradycardia (<30 beats x min(-1)) and severe hypotension were also observed. Cardiopulmonary resuscitation using epinephrine was immediately started. Re-intubation of the trachea was difficult due to severe edema, but eventually performed using a tube of a smaller size (internal diameter 7.0 mm). Subsequent investigations using a fiberscope confirmed extensive soft tissue swelling, maximal at the level of the vocal cord and extending up- and down-wards to the trachea, indicating that the obstruction is caused by severe laryngeal edema. We believe that edema may have been caused by hypoalbuminemia (1.3 g x dl(-1)) at the end of operation. Therefore, it should be noted that hypoalbuminemia may cause laryngeal edema leading to acute airway obstruction.