Comparative studies on picosecond-resolved fluorescence of d-amino acid oxidases from human with one from porcine kidney. Photoinduced electron transfer from aromatic amino acids to the excited flavin.

Fluorescence dynamics of human d-amino acid oxidase (hDAAO) and its five inhibitors have been studied in the picoseconds time domain, and compared with one in d-amino acid oxidase from porcine kidney (pkDAAO) reported. The fluorescence lifetimes were identified as 47 ps in the dimer, 235 ps in the monomer, which are compared with those of pkDAAO (45 ps-185 ps). The fluorescence lifetimes of the hDAAO did not change upon the inhibitor bindings despite of modifications in the absorption spectra. This indicates that the lifetimes of the complexes are too short to detect with the picosecond lifetime instrument. Numbers of the aromatic amino acids are similar between the both DAAOs. The fluorescence lifetimes of hDAAO were analysed with an ET theory using the crystal structure. The difference in the lifetimes of the dimer and monomer was well described in terms of difference in the electron affinity of the excited isoalloxazine (Iso*) between the two forms of the protein, though it is not known whether the structure of the monomer is different from the dimer. Three fastest ET donors were Tyr314, Trp52 and Tyr224 in the dimer, while Tyr314, Tyr224 and Tyr55 in the monomer, which are compared to those in pkDAAO, Tyr314, Tyr224 and Tyr228 in the dimer, and Tyr224, Tyr314 and Tyr228 in the monomer. The ET rate from Trp55 in hDAAO dimer was much faster compared to the rate in pkDAAO dimer. A rise component with negative pre-exponential factor was not observed in hDAAO, which are found in pkDAAO.

Tidal volume and airway pressure under percutaneous transtracheal ventilation without a jet ventilator: comparison of high-flow oxygen ventilation and manual ventilation in complete and incomplete upper airway obstruction models.

PURPOSE: Percutaneous transtracheal ventilation (PTV) can be life-saving in a cannot ventilate, cannot intubate situation. The aim of this study was to investigate the efficacy of PTV by measuring tidal volumes (VTs) and airway pressure (Paw) in high-flow oxygen ventilation and manual ventilation using a model lung. METHODS: We examined 14G, 16G, 18G, and 20G intravenous catheters and minitracheotomy catheters. In high-flow oxygen ventilation, the flow was set to 10 L/min, while the inspiratory:expiratory phases (I:E) were 1 s:4 s in the complete upper airway obstruction model and 1 s:1 s in the incomplete obstruction model. In manual ventilation, I:E were 2 s:4 s in the complete obstruction model and 2 s:3 s in the incomplete obstruction model. We ventilated through each catheter for 2 min and measured VT and Paw. RESULTS: In high-flow ventilation, the average VTs were approximately 150 ml and <100 ml with 14G catheters in complete and incomplete upper airway obstruction, respectively. The VTs obtained were reduced when the bore size was decreased. In manual ventilation, the average VTs were over 300 ml and approximately 260 ml with 14G catheters in complete and incomplete upper airway obstruction, respectively. In high-flow ventilation, the airway pressure tended to be higher. The minitracheotomy catheters produced over 800 ml of VT and created almost no positive end-expiratory pressure. CONCLUSIONS: High-flow ventilation tends to result in higher airway pressure despite a smaller VT, which is probably due to a PEEP effect caused by high flow.

[Analgesic efficacy of transversus abdominis plane block after open abdominal aortic aneurysm surgery].

BACKGROUND: Ultrasound (US)-guided transversus abdominis plane (TAP) block is widely-spread analgesic technique for the patients undergoing abdominal surgery and can be provided safely for the patients receiving anticoagulation therapy. We conducted a retrospective comparative trial of analgesic efficacy between the patient who received US-guided TAP block with postoperative continuous iv-fentanyl infusion (group T) and those who received epidural analgesia (group E). METHODS: Twenty three patients who had undergone abdominal aortic replacement were analyzed retrospectively. The number of patients in group T was 12, and those in group E was 11. The postoperative first ambulation day, the postoperative first oral feeding day, the length of hospital stay, the use of rescue analgesic medication, and the incidence of postoperative nausea and vomiting (PONV) were compared between the two groups. P<0.05 was considered significant RESULTS: There were no significant differences in baseline characteristics between the two groups. There were no significant differences in postoperative first ambulation day (P=0.97), the postoperative first oral feeding day (P=0.46), the length of hospital stay (P= 0.32), the number of times of rescue analgesic medication (P=0.55), and the incidence of PONV between the two groups. CONCLUSIONS: US-guided TAP block is a useful option as analgesic technique for patients undergoing abdominal aortic replacement

Markedly elevated procalcitonin in early postoperative period in pediatric open heart surgery: a prospective cohort study.

BACKGROUND: We encountered markedly elevated procalcitonin (PCT) among pediatric patients during the early postoperative period of open heart surgery. The purpose of this study is to investigate what factors are associated with the PCT elevation. METHODS: Fifty-two pediatric patients undergoing cardiac surgery with cardiopulmonary bypass (CPB) were enrolled. Plasma PCT, aspartate aminotransferase/alanine aminotransferase (AST/ALT), creatinine, lactate, and C-reactive protein (CRP) were measured on admission to ICU and during the postoperative period. The patients were categorized into high (group H) and low (group L) groups according to their peak PCT levels. Aorta cross-clamp (ACC), CPB time, ICU stay, mechanical ventilation period, peak AST/ALT, creatinine, lactate, and CRP levels were compared. RESULTS: ACC and CPB times, ICU stay period, and mechanical ventilation period were significantly longer in group H compared with group L (118.7 ± 51.6 vs. 49.4 ± 43.5 min, 244.5 ± 65.7 vs. 122.9 ± 63.0 min, 7.9 ± 4.6 vs. 4.0 ± 4.5 days, and 6.3 ± 4.1 vs. 2.9 ± 4.2 days, respectively; p < 0.01). Peak AST and creatinine were significantly higher in group H compared with group L (999.0 ± 1,990.3 vs. 88.3 ± 43.0 U/l and 0.84 ± 0.77 vs. 0.41 ± 0.17 mg/dl, respectively; p < 0.05). CONCLUSIONS: ACC and CPB time-related perioperative stress is associated with elevated PCT; an association between ICU stay and mechanical ventilation period, liver enzymes, and creatinine levels was observed. PCT may be a good predictor of postoperative severity and organ dysfunction.

Spinal cord stimulation for a woman with complex regional pain syndrome who wished to get pregnant.

A woman with complex regional pain syndrome (CRPS) in the right lower extremity who wished to discontinue medications to get pregnant underwent implantation of a spinal cord stimulation system (SCS). An electrode lead was placed at Th(10-11) in the epidural space, accessed via the L(2-3) interspace with a paramedian approach, and a pulse generator was implanted in the left buttock. She kept the SCS on 24 h a day. After she had experienced several chemical abortions, finally she got pregnant via artificial insemination. She had an uneventful delivery of a healthy baby by cesarean resection under spinal anesthesia. In a patient with CRPS who has an implanted SCS system and wishes to get pregnant, the electrode lead into the low thoracic epidural space should be accessed via the high lumbar intervertebral space in consideration of a future requirement for spinal or epidural anesthesia for cesarean section. The generator should be placed in the buttock to prevent impairment of the SCS system being caused by the enlarged abdomen during pregnancy. Although we were apprehensive of adverse effects owing to the electromagnetic field force and change of blood flow in the pelvic viscera, our patient had a successful delivery. SCS is a favorable option for patients with CRPS who wish to get pregnant.

Precise control of end-tidal carbon dioxide and oxygen improves BOLD and ASL cerebrovascular reactivity measures.

In-depth investigation of cerebrovascular blood flow and MR mechanisms underlying the blood oxygenation level dependent signal requires precise manipulation of the arterial partial pressure of carbon dioxide and oxygen, measured by their noninvasive surrogates, the end-tidal values. The traditional methodology consists of administering a fixed fractional concentration of inspired CO(2), but this causes a variable ventilatory response across subjects, resulting in different values of end-tidal partial pressures of CO(2) and O(2). In this study, we investigated whether fine control of these end-tidal partial pressures would improve stability and predictability of blood oxygenation level dependent and arterial spin labeling signals for studying cerebrovascular reactivity. In 11 healthy volunteers, we compared the MR signals generated by the traditional fixed fractional concentration of inspired CO(2) method to those of an automated feed-forward system, a simpler, safer, and more compact alternative to dynamic end-tidal forcing systems, designed to target constant end-tidal partial pressures of CO(2) and O(2). We found that near square-wave changes in end-tidal partial pressure of CO(2) of 5, 7.5, and 10 mm Hg (+/-1.01 mm Hg within two to three breaths) and constrained changes in the end-tidal partial pressure of O(2) (<10 mm Hg) induced cerebral vascular reactivity measurements with faster transitions, together with improved stability and gradation, than those achieved with the traditional fixed fractional concentration of inspired CO(2) method.

A novel skin-traction method is effective for real-time ultrasound-guided internal jugular vein catheterization in infants and neonates weighing less than 5 kilograms.

BACKGROUND: Internal jugular vein (IJV) catheterization in pediatric patients is sometimes difficult because of the small sizes of veins and their collapse during catheterization. To facilitate IJV catheterization, we developed a novel skin-traction method (STM), in which the point of puncture of the skin over the IJV is stretched upward with tape during catheterization. In this study, we examined whether the STM increases the cross-sectional area of the vein and thus facilitates catheterization. METHODS: This was a prospective study conducted from December 2006 to June 2008. We enrolled 28 consecutive infants and neonates weighing <5 kg who underwent surgery for congenital heart disease. The patients were randomly assigned to a group in which STM was performed (STM group) or a group in which it was not performed (non-STM group). The cross-sectional area and diameter of the right IJV in the flat position and 10 degrees Trendelenburg position with and without applying STM were measured. We determined time from first skin puncture to the following: (a) first blood back flow, (b) insertion of guidewire, and (c) insertion of catheter. Number of punctures, success rate, complications, and degree of IJV collapse during advancement of the needle (estimated as decrease of anteroposterior diameter during advancement of the needle compared with the diameter before advancement) were also examined. RESULTS: STM significantly increased the cross-sectional area and the anteroposterior diameter of the IJV in both positions. The time required to insert the catheter was significantly shorter in the STM group, probably mainly due to a shorter guidewire insertion time. The degree of IJV collapse during advancement of the needle was much lower in the STM group. CONCLUSIONS: STM facilitates IJV catheterization in infants and neonates weighing <5 kg by enlarging the IJV and preventing vein collapse.

Skin-traction method prevents the collapse of the internal jugular vein caused by an ultrasound probe in real-time ultrasound-assisted guidance.

PURPOSE: Real-time ultrasound-assisted guidance for catheterization of the internal jugular vein (IJV) is known to be useful, especially for a small-sized vein, which is difficult to catheterize. However, one of the problems with real-time ultrasound-assisted guidance is that the ultrasound probe itself can collapse the vein. We have developed a novel "skintraction method (STM)", in which the puncture point of the skin over the IJV is stretched upwards with several pieces of surgical tape in the cephalad and caudal directions with the aim being to facilitate catheterization of the IJV. We examined whether this method increased the compressive force required to collapse the IJV. METHODS: In ten volunteers, the compressive force required to collapse the right IJV, and the cross-sectional area and anteroposterior and transverse diameters of the IJV were measured with ultrasound imaging in the supine position (SP) with or without the STM or in the Trendelenburg position of 10 degrees head-down (TP) without the STM. RESULTS: The compressive force to required to collapse the vein was increased significantly with the STM, while the crosssectional area and anteroposterior diameter of the vein in the SP with STM were similar to those in the TP without the STM. CONCLUSION: With the STM, not only the cross-sectional area but also the compressive force required to collapse the IJV increased. Thus, the STM may facilitate real-time ultrasoundassisted guidance for catheterization of the IJV by maintaining the cross-sectional area of the vein during the guidance.

A simple, lightweight CPAP-delivery device, composed of a three-way stopcock, for the nondependent lung.

PURPOSE: We aimed to introduce a simple, lightweight continuous positive airway pressure (CPAP)-delivery device for the nondependent lung during one-lung ventilation, to investigate how the type of three-way stopcocks, and the compliance and resistance of a test lung affect the relationship between the oxygen flow rate and CPAP level produced, and to examine how the device works in a clinical setting. METHODS: In the test lung study, the bronchial blocker of a Univent tube was connected to a test lung. The effects of oxygen-flow rate, types of three-way stopcocks, and compliance and resistance of the test lung on the CPAP levels were studied. In the clinical study, the lightweight device was used to treat hypoxia in seven patients during one-lung ventilation with the bronchial blocker. RESULTS: In the test lung study, the CPAP level produced by the device was proportional to the oxygen-flow rate, dependent on the type of three-way stopcock used, and independent of the compliance or resistance of the test lung. There was no discrepancy between the plateau pressures of the test lung and the monitoring port of an additional stopcock at any degree of compliance or resistance of the test lung at any oxygen-flow rate. Therefore, the relationship between the oxygen-flow rate and CPAP level can be ensured in advance before application to the lung, with an additional three-way stopcock of which the distal end is occluded. In the clinical study, peripheral oxygen sataration Sp(O2) improved while the CPAP level ranged from 2.8 to 5.4 cmH2O. CONCLUSION: The lightweight CPAP delivery-device can provide variable CPAP levels by adjusting the oxygen-flow rate without real-time monitoring of the pressure.

Adaptation and mal-adaptation to ambient hypoxia; Andean, Ethiopian and Himalayan patterns.

The study of the biology of evolution has been confined to laboratories and model organisms. However, controlled laboratory conditions are unlikely to model variations in environments that influence selection in wild populations. Thus, the study of "fitness" for survival and the genetics that influence this are best carried out in the field and in matching environments. Therefore, we studied highland populations in their native environments, to learn how they cope with ambient hypoxia. The Andeans, African highlanders and Himalayans have adapted differently to their hostile environment. Chronic mountain sickness (CMS), a loss of adaptation to altitude, is common in the Andes, occasionally found in the Himalayas; and absent from the East African altitude plateau. We compared molecular signatures (distinct patterns of gene expression) of hypoxia-related genes, in white blood cells (WBC) from Andeans with (n = 10), without CMS (n = 10) and sea-level controls from Lima (n = 20) with those obtained from CMS (n = 8) and controls (n = 5) Ladakhi subjects from the Tibetan altitude plateau. We further analyzed the expression of a subset of these genes in Ethiopian highlanders (n = 8). In all subjects, we performed the studies at their native altitude and after they were rendered normoxic. We identified a gene that predicted CMS in Andeans and Himalayans (PDP2). After achieving normoxia, WBC gene expression still distinguished Andean and Himalayan CMS subjects. Remarkably, analysis of the small subset of genes (n = 8) studied in all 3 highland populations showed normoxia induced gene expression changes in Andeans, but not in Ethiopians nor Himalayan controls. This is consistent with physiologic studies in which Ethiopians and Himalayans show a lack of responsiveness to hypoxia of the cerebral circulation and of the hypoxic ventilatory drive, and with the absence of CMS on the East African altitude plateau.

Non-invasive prospective targeting of arterial P(CO2) in subjects at rest.

Accurate measurements of arterial P(CO(2)) (P(a,CO(2))) currently require blood sampling because the end-tidal P(CO(2)) (P(ET,CO(2))) of the expired gas often does not accurately reflect the mean alveolar P(CO(2)) and P(a,CO(2)). Differences between P(ET,CO(2)) and P(a,CO(2)) result from regional inhomogeneities in perfusion and gas exchange. We hypothesized that breathing via a sequential gas delivery circuit would reduce these inhomogeneities sufficiently to allow accurate prediction of P(a,CO(2)) from P(ET,CO(2)). We tested this hypothesis in five healthy middle-aged men by comparing their P(ET,CO(2)) values with P(a,CO(2)) values at various combinations of P(ET,CO(2)) (between 35 and 50 mmHg), P(O(2)) (between 70 and 300 mmHg), and breathing frequencies (f; between 6 and 24 breaths min(-1)). Once each individual was in a steady state, P(a,CO(2)) was collected in duplicate by consecutive blood samples to assess its repeatability. The difference between P(ET,CO(2)) and average P(a,CO(2)) was 0.5 +/- 1.7 mmHg (P = 0.53; 95% CI -2.8, 3.8 mmHg) whereas the mean difference between the two measurements of P(a,CO(2)) was -0.1 +/- 1.6 mmHg (95% CI -3.7, 2.6 mmHg). Repeated measures ANOVAs revealed no significant differences between P(ET,CO(2)) and P(a,CO(2)) over the ranges of P(O(2)), f and target P(ET,CO(2)). We conclude that when breathing via a sequential gas delivery circuit, P(ET,CO(2)) provides as accurate a measurement of P(a,CO(2)) as the actual analysis of arterial blood.

Vagal nerve activity contributes to improve the efficiency of pulmonary gas exchange in hypoxic humans.

The aim of this study was to test our hypothesis that both phasic cardiac vagal activity and tonic pulmonary vagal activity, estimated as respiratory sinus arrhythmia (RSA) and anatomical dead space volume, respectively, contribute to improve the efficiency of pulmonary gas exchange in humans. We examined the effect of blocking vagal nerve activity with atropine on pulmonary gas exchange. Ten healthy volunteers inhaled hypoxic gas with constant tidal volume and respiratory frequency through a respiratory circuit with a respiratory analyser. Arterial partial pressure of O(2) (P(aO(2))) and arterial oxygen saturation (S(pO(2))) were measured, and alveolar-to-arterial P(O(2)) difference (D(A-aO(2))) was calculated. Anatomical dead space (V(D,an)), alveolar dead space (V(D,alv)) and the ratio of physiological dead space to tidal volume (V(D,phys)/V(T)) were measured. Electrocardiogram was recorded, and the amplitude of R-R interval variability in the high-frequency component (RRIHF) was utilized as an index of RSA magnitude. These parameters of pulmonary function were measured before and after administration of atropine (0.02 mg kg(-1)). Decreased RRIHF (P < 0.01) was accompanied by decreases in P(aO(2)) and S(pO(2)) (P < 0.05 and P < 0.01, respectively) and an increase in D(A-aO(2)) (P < 0.05). Anatomical dead space, V(D,alv) and V(D,phys)/V(T) increased (P < 0.01, P < 0.05 and P < 0.01, respectively) after atropine administration. The blockade of the vagal nerve with atropine resulted in an increase in V(D,an) and V(D,alv) and a deterioration of pulmonary oxygenation, accompanied by attenuation of RSA. Our findings suggest that both phasic cardiac and tonic pulmonary vagal nerve activity contribute to improve the efficiency of pulmonary gas exchange in hypoxic conscious humans.

Anesthetic and airway management of general anesthesia in a patient with Meckel-Gruber syndrome.

Meckel-Gruber syndrome, characterized by occipital encephalocele, microcephaly, polydactyly, cleft lip or palate, mandibular micrognathism, and anatomical abnormality of the larynx and tongue, along with other associated malformations, is in the list of diseases associated with difficult airway. However, there has been no report on the management of general anesthesia and airway management for such patients. A 2-year-old girl with Meckel-Gruber syndrome was scheduled for cardioplasty and gastrostomy for gastroesophageal reflux under general anesthesia. Preoperative examination revealed obesity, microgenia, dysspondylism, proteinuria, hypoplastic kidneys, and stenosis of the anal canal. Although we anticipated some difficulty with the intubation and prepared several alternative methods for intubation, such as a bronchofiberscope and a laryngeal mask airway, tracheal intubation was completed without difficulty using conventional laryngoscopy after inhalational induction with sevoflurane. Because most patients with this syndrome die before and shortly after delivery, those who survive to some age might have less severe deformities.

The changes in pulmonary capillary blood flow and anatomical dead space during pulmonary resection under one-lung ventilation.

Pulmonary capillary blood flow (PCBF), anatomical dead space (VDaw) and SpO2 were measured and recorded continuously using NICO (Novametrix Medical Systems Inc, USA) in 2 cases during pulmonary resection under one-lung ventilation (OLV). A pulmonary artery catheter was inserted and continuous CO (CCO) was also measured in case 2. In both cases PCBF decreased by half when one lung was blocked. CCO was unchanged before and after one lung blockade in case 2. During OLV, SpO2, which had initially decreased, gradually increased along with a very slow increase in PCBF. The decreased PCBF obtained with NICO represents the pulmonary blood flow of the ventilated (non-blocked) lung. The gradual increase in PCBF with NICO during OLV may express the compensatory effects of hypoxic pulmonary vasoconstriction. By measuring VDaw before, during and after one-lung ventilation, we were able to calculate the bronchial volume of the non-ventilated lung and that of the resected lung.

A case of complex regional pain syndrome type II after transradial coronary intervention.

The transradial approach for coronary catheterization is now a routine technique without serious complications at the puncture site. We report a case of complex regional pain syndrome type II (CRPS type II) in the hand after the transradial coronary intervention, which may alert medical personnel that the technique may cause serious regional pain with disability. A 61-year-old woman underwent coronary intervention via the right radial artery for the treatment of unstable angina. After the operation she complained of severe pain in the right hand, consistently felt along the median nerve distribution. The nerve conduction study suggested carpal tunnel syndrome. We made a diagnosis of CRPS type II, and the patient received stellate ganglion blockade, cervical epidural blockade, and administration of amitriptyline and loxoprofen. The symptoms gradually improved and her activities of daily living markedly improved. The median nerve appeared to be damaged by local compression and potential ischemia. Careful attention should be paid to avoid CRPS type II, associated with excess compression.

Self-oscillation of polymer chains with rhythmical soluble-insoluble changes.

Self-oscillation of polymer chains in an aqueous solution has been achieved. The ruthenium catalyst for the Belousov-Zhabotinsky reaction was polymerized by using N-isopropylacrylamide and dissolved into the solution containing the BZ substrates. Periodical soluble-insoluble changes of the polymer chain were spontaneously induced by the BZ reaction. The conformational oscillations of the polymer were measured as the optical transmittance changes of the solution. This is the first report that rhythmical and reversible soluble-insoluble changes of polymer chains are realized under constant and homogeneous conditions. The transducing system from chemical energy of the BZ reaction to optical information has been constructed.