Relationship between perioperative cardiopulmonary bypass time, platelet count, fibrinogen level, rotational thromboelastometry data, antithrombin level, and blood loss volume and the effects of deep hypothermic circulatory arrest: An observational study

INTRODUCTION

We hypothesized that perioperative fibrinogen level, platelet count, and rotational thromboelastometry (ROTEM) data values decrease in proportion to cardiopulmonary bypass (CPB) time, particularly in patients who underwent deep hypothermic circulatory arrest (DHCA).

METHODS

A total of 160 patients were enrolled and divided into the following three groups depending on CPB time: <2-h, 2- 3-h, and >3-h groups. Blood samples were obtained during CPB weaning. Platelet count, ROTEM data, fibrinogen level, and antithrombin level were determined. For propensity matching, we selected 15 patients who underwent DHCA and 15 patients who did not undergo DHCA and used propensity scores to match CPB time and other characteristics.

RESULTS

The <2-h, 2-3-h, and >3-h groups included 74, 63, and 23 patients, respectively. No significant differences in platelet count and fibrinogen level were observed between the groups. Antithrombin level and amplitude of clot firmness at 10 min in the EXTEM and FIBTEM tests were lowest in the >3-h group. Similarly, blood loss volume and transfusion volume were highest in the >3-h group. Significant differences in platelet count, ROTEM data, lowest esophageal and bladder temperatures, and transfusion volume were observed between patients who underwent DHCA and patients who did not undergo DHCA.

CONCLUSIONS

The longer the CPB time, the greater the perioperative blood loss volume and transfusion volume, particularly if CPB time is greater than 3 hours. Sub-group analysis revealed that DHCA affects perioperative platelet count and function as well as blood loss volume.

Hemostatic capability of ultrafiltrated fresh frozen plasma compared to cryoprecipitate

This in vitro study evaluated the potential hemostatic effect of fresh frozen plasma (FFP) ultrafiltration on clotting factors, coagulation parameters, and plasma properties. ABO-specific units of FFP (n = 40) were prepared for the concentrated FFP and cryoprecipitate. Plasma water was removed from FFP by ultrafiltration using a dialyzer with a pump running at a 300 mL/min. The aliquot of each concentrated FFP after 50, 100, 200, and 250 mL of fluid removal were measured the standard coagulation assay, clotting activity, and plasma properties to compare those parameters of cryoprecipitate. Concentrated FFP contained 36.5% of fibrinogen in FFP with a mean concentration of 7.2 g/L, lower than the cryoprecipitate level. The levels of factor VIII (FVIII), von Willebrand factor (VWF):antigen (Ag), and VWF:ristocetin cofactor (RCo) were also lower in concentrated FFP, whereas the levels of factor V, factor IX, factor XIII, antithrombin and albumin was higher in concentrated FFP. Maximum clot firmness (MCF) in thromboelastometry was approximately one-half of that in cryoprecipitate. Although the levels of VWF:Ag, VWF:RCo, and FVIII differed depending on the ABO blood types, fibrinogen levels, and MCF were not significantly different among the ABO blood groups in FFP and concentrated FFP.

Effects of Hemodilution on Clot Waveform Analysis Parameters, Clotting Factors, and Thrombin Generation Assays in a Dilutional Model Based on Analysis of 11 Healthy Male Blood Donors

Background

Clot wave analysis (CWA) during activated partial thromboplastin time (aPTT) measures the speed and extent of fibrin polymerization in the plasma. This study aimed to evaluate the effects of hemodilution on CWA parameter, clotting factors, and thrombin generation assays in a dilutional model.

Material/Methods

Platelet-poor plasma obtained from 11 healthy male volunteers was diluted with 0.9% sodium chloride by 10–80% to analyze coagulation profiles, CWA, clotting factors, and thrombin generation assays. CWA includes 5 parameters: the time-dependent variable (aPTT), rate/acceleration (min1, min2, and max2), and magnitude of signal change (delta).

Results

Critically low activities of 30% for clotting factors and 100 mg/dl of fibrinogen were determined at dilutions of 70% and 60%, respectively. Peak thrombin and endogenous thrombin potential were significantly lower compared with baseline after 50% and 80% dilution, respectively. aPTT did not correlate with the decrease in the clotting factors up to dilutions of 50% and subsequently became abnormal values. As the change in rate/acceleration parameters parallels the time course of clotting factor activity in a dilution-dependent linear manner, these parameters indicate an intervention threshold at critically low activities of clotting factors. The strongest correlations were observed between clotting factors and aPTT, clotting factors and min2, delta and peak thrombin (r=0.95), and delta and fibrinogen (r=0.98).

Conclusions

aPTT was significantly correlated with clotting factors, while the rate/acceleration parameters and delta changed with variation in thrombin and fibrinogen generation. These findings may help in evaluating coagulability.

Effects of room temperature and cold storage on the metabolic and haemostatic properties of whole blood for acute normovolaemic haemodilution

Background

Acute normovolaemic haemodilution (ANH), as a blood-conservation technique, avoids the need for allogeneic blood transfusions. The historic practice of cold-storing type-O whole blood (WB) in military fields popularised the transfusion of refrigerated WB to treat acute bleeding. In this study, we compared the effects of room temperature (RT) and refrigeration up to 24 hours on the coagulation properties of WB for ANH.

Materials and methods

Each WB sample, collected from 12 male volunteers, was divided into two parts, one stored at RT and the other refrigerated for 24 hours. Complete blood counts (CBC), blood gas levels, and coagulation profiles were measured, and rotational thromboelastometry (ROTEM) measurements were performed at the initial collection time point (baseline) and at 6, 12, and 24 hours after initial collection.

Results

The preservation of platelet aggregation response induced by arachidonic acid and adenosine diphosphate was better in cold-stored WB compared to that in RT-stored WB. The platelet aggregation response induced by thrombin receptor-activating peptide 6 was significantly decreased in all samples after 24 hours of storage when compared with that at baseline. The lactate levels in WB stored at RT increased significantly after 6 hours of storage compared to that of cold-stored samples. There were no significant differences in CBC, coagulation parameters, and ROTEM variables between the cold-stored and RT-stored WB samples.

Conclusion

WB for ANH stored in the refrigerator showed better metabolic characteristics after 6 hours of storage and better aggregation response after 12 hours of storage than WB stored at RT.

MEASUREMENT OF HALF-VALUE LAYER IN COMPUTED TOMOGRAPHY SCANNERS USING LUMINESCENCE OF POLYETHERSULFONE RESIN BY X-RAY IRRADIATION

In this study, a method for estimating the half-value layer (HVL) and effective energy (Eeff) by imaging the luminescence from a polyethersulfone (PES) resin with rotating irradiation of X-rays in a computed tomography scanner was developed. The luminescence of the PES resin was imaged using a charge-coupled device camera. The PES-HVL was determined from the luminance attenuation profile corresponding to the X-ray attenuation within the resin. The PES-HVLs for tube potentials of 80-135 kVp were converted into Eeff values and were compared to those of a conventional lead-covered case method. The Eeff obtained using the proposed luminescence imaging method agreed within ~3.9% of that obtained using the conventional method. Moreover, dose simulations based on the X-ray spectrum calculated from the HVLs were performed using a poly(methyl methacrylate) phantom with a diameter of 16 cm. The simulated doses based on the luminescence imaging method agreed with the in-phantom dosimetry within ~9%.

Storage-Related Changes in Autologous Whole Blood and Irradiated Allogeneic Red Blood Cells and Their Ex Vivo Effects on Deformability, Indices, and Density of Circulating Erythrocytes in Patients Undergoing Cardiac Surgery With Cardiopulmonary Bypass

OBJECTIVES

Blood-processing techniques and preservation conditions cause storage lesions, possibly leading to adverse outcomes after transfusion. The authors investigated the metabolic changes and deformability of red blood cells (RBCs) during storage and determined the effect of storage lesions on circulating RBCs during cardiac surgery.

DESIGN

Prospective study.

SETTING

Tertiary care center affiliated with a university hospital.

PARTICIPANTS

Adults who underwent elective cardiac surgery requiring cardiopulmonary bypass.

INTERVENTIONS

The authors collected aliquots of autologous and irradiated allogeneic RBCs and blood samples from seven patients who received autologous whole blood and nine patients who received irradiated allogeneic RBCs before incision (baseline), at the start and end of cardiopulmonary bypass, and at completion of surgery.

MEASUREMENTS AND MAIN RESULTS

The authors analyzed RBC deformability, erythrocyte indices, and density distribution to evaluate blood banking-induced alterations of autologous and allogeneic RBCs and changes in circulating RBCs in recipients, after blood transfusion. Time-dependent biochemical changes and significant decreases in deformability during storage occurred in both groups; however, homologous RBCs had significantly lower deformability than autologous RBCs. Trends in mean corpuscular volume and mean corpuscular hemoglobin concentration differed in both groups. In the homologous transfusion group, during cardiac surgery, RBC deformability, mean corpuscular volume, and mean corpuscular hemoglobin concentration showed significant changes compared with baseline values, and a greater number of denser subpopulations was observed at surgery completion.

CONCLUSIONS

Blood-processing techniques contribute to storage lesions, suggesting that transfusion of autologous whole blood, rather than allogeneic RBCs, could maintain the ability of circulating RBCs to deform and lead to potentially better transfusion outcomes.

Left atrial thrombus formation within a few days of hospitalization in semi-acute ischemic heart disease despite no atrial fibrillation and mitral stenosis: a case report

BACKGROUND

Currently, the occurrence of left atrial thrombus despite the provision of heparinization within a few days of hospitalization without atrial fibrillation (AF) and mitral stenosis (MS) is rarely reported.

CASE PRESENTATION

A 71-year-old woman presented with chest discomfort and dyspnea. Examination revealed ST elevation with sinus rhythm, congestive heart failure, and moderate mitral regurgitation (MR) by transthoracic echocardiography (TTE). Diuretics, a coronary vasodilator, and unfractionated heparin (15,000 units/day) were administered. Four days after hospitalization, her C-reactive protein level had increased; therefore, TTE was repeated, revealing a thrombus in the left atrial appendage, which was probably affected by heparin resistance because of low antithrombin (49%). On day 5, the patient underwent emergency removal of the thrombus, mitral valve replacement, and coronary artery bypass.

CONCLUSION

Patients can exhibit low left ventricular contractility, even sinus rhythm without MS. Thus, TTE and subsequent coagulation tests including antithrombin must be performed to prevent thrombus.

Refractory ventricular arrhythmias during aortic valve replacement and cardiac artery bypass requiring 16 attempts of electrical cardioversion: a case report

BACKGROUND

We report a patient in whom we failed to suppress ventricular fibrillation (VF) using nifekalant but succeeded using amiodarone during cardiopulmonary bypass (CPB).

CASE PRESENTATION

A 65-year-old male with hemodialysis complained of dyspnea and was diagnosed with aortic valve stenosis and angina pectoris; he was opted for elective aortic valve replacement. When the aortic forceps were declamped during CPB, immediate VF was observed; several attempts of electrical cardioversion (EC) with lidocaine and landiolol and three administrations of nifekalant were temporarily effective. However, the rhythm subsequently changed to torsades de pointes. We administered 2 g of magnesium sulfate followed by three doses of amiodarone and initiated continuous infusion. Furthermore, we initiated the pacemaker and intra-aortic balloon pumping. These procedures seemed to be effective; the sinus rhythm was sustained until the end of the surgery.

CONCLUSION

We experienced a cardiac surgery requiring 16 EC attempts to terminate the life-threatening arrhythmias using amiodarone.

Leak-free million-fold DNA amplification with locked nucleic acid and targeted hybridization in one pot

An isothermal cascade reaction that exponentially amplifies pre-designed, single-stranded DNA as a sensor and signal amplifier module for DNA-based computing and molecular robotics was developed. Taking advantage of the finding that locked nucleic acid can suppress problematic ab initio DNA synthesis, up to million-fold amplification rates and concurrent hybridization were achieved at a physiological temperature in a single reactor. Although the effect of locked nucleic acid introduction to the templates was complicated, undesired leak DNA amplification was generally suppressed in the amplification reaction for distinct DNA sequences. The present reaction that senses one DNA as an input and generates a large amount of another DNA as an output, exhibiting a high correlation between the molecular concentration and the amplification time, is applicable for nucleic acid quantification.

MEASUREMENT OF INTERNAL RADIATION DOSE DISTRIBUTION IN CT EXAMINATIONS USING POLYETHYLENE TEREPHTHALATE RESIN

This study proposes a new dosimetry method for the estimation of the internal radiation dose distribution of a subject undergoing computed tomography (CT) examinations. In this novel method, dose distribution of a subject by CT scans was estimated based on radiophotoluminance distribution with polyethylene terephthalate (PET) resin which was cut to the average head size of a Japanese 1-year-old child. The difference in dose distribution depending on the type of bowtie filter was visualized by imaging luminance distribution with the PET phantom using a charge-coupled device camera. Dose distribution images simulated from a water phantom of the same size as the PET phantom were compared with the luminance distribution images. The linear correlation was demonstrated between luminance of the PET phantom and the simulated water dose. In comparison with the simulated water doses and the converted water doses from luminance of the PET phantom, the relative differences were within 20%.

Changes in heparin dose response slope during cardiac surgery: possible result in inaccuracy in predicting heparin bolus dose requirement to achieve target ACT

Introduction:

The substantial interpatient variability in heparin requirement has led to the use of a heparin dose response (HDR) technique. The accuracy of Hepcon-based heparin administration in achieving a target activated clotting time (ACT) using an HDR slope remains controversial.

Methods:

We prospectively studied 86 adult patients scheduled for cardiac surgery requiring cardiopulmonary bypass. The total dose of calculated heparin required for patient and pump priming was administered simultaneously to achieve a target ACT of 450 s for HDR on the Hepcon HMS system. Blood samples were obtained after the induction of anesthesia, at 3 min after heparin administration and after the initiation of CPB to measure kaolin ACT, HDR slope, whole-blood heparin concentration based on the HDR slope and anti-Xa heparin concentration, antithrombin and complete blood count.

Results:

The target ACT of 450 s was not achieved in 68.6% of patients. Compared with patients who achieved the target ACT, those who failed to achieve their target ACT had a significantly higher platelet count at baseline. Correlation between the HDR slope and heparin sensitivity was poor. Projected heparin concentration and anti-Xa heparin concentration are not interchangeable based on the Bland–Altman analysis.

Conclusion:

It can be hypothesized that the wide discrepancy in HDR slope versus heparin sensitivity may be explained by an inaccurate prediction of the plasma heparin level and/or the change in HDR of individual patients, depending on in vivo factors such as extravascular sequestration of heparin, decreased intrinsic antithrombin activity level and platelet count and/or activity.

A dramatic enhancing effect of InBr3 towards the oxidative Sonogashira cross-coupling reaction of 2-ethynylanilines

The addition of InBr3 to the oxidative Sonogashira cross-coupling reaction of 2-ethynylaniline with (E)-trimethyl(3,3,3-trifluoroprop-1-enyl)silane led to a dramatic increase in the reactivity to afford the corresponding 1,3-enynes bearing a trifluoromethyl group on their terminal sp(2) carbon. The subsequent cyclization of these 1,3-enynes under palladium catalysis provides access to the corresponding indoles bearing a 3,3,3-trifluoroprop-1-enyl group at their 2-position.

[The Use of Thromboelastometry and Tranexamic Acid Reduces Blood Loss and Transfusion Requirements in Cardiac Surgery under Cardiopulmonary Bypass]

BACKGROUND

We evaluated whether using thromboelastometry and tranexamic acid influenced blood loss and transfusion requirements in cardiac surgery requiring cardiopulmonary bypass.

METHODS

We perfomed a retrospective analysis examining perioperative coagulation results, and the transfusion requirements of concentrated red cells (CRCs), fresh frozen plasma (FFP) and platelet administration between 12 months before and 10 months after thromboelastometry and tranexamic acid had been introduced in our institution. We also recorded patients' demographic details, the surgery performed and patient outcomes.

RESULTS

After the introduction of thromboelastometry and tranexamic acid, fewer units of CRC were transfused during surgery, and fewer patients required postoperative CRC transfusion. Intra- and postoperative FFP requirements were also reduced. Intraoperative blood loss, blood loss in the first 24 hr after surgery, and length of hospital stay were also reduced.

CONCLUSIONS

The use of ROTEM and tranexamic acid can potentially reduce blood loss and transfusion requirements in cardiac surgery.

The fentanyl concentration required for immobility under propofol anesthesia is reduced by pre-treatment with flurbiprofen axetil

PURPOSE

We hypothesized that nonsteroidal anti-inflammatory drugs decrease the plasma fentanyl concentration required to produce immobility in 50% of patients in response to skin incision (Cp50incision) compared with placebo under target-controlled infusion (TCI) propofol anesthesia.

METHODS

Sixty-two unpremedicated patients scheduled to undergo gynecologic laparoscopy were randomly assigned to receive placebo (control group) or flurbiprofen axetil 1 mg·kg(-1) (flurbiprofen group) preoperatively. General anesthesia was induced with fentanyl and propofol, and intubation was performed after succinylcholine 1 mg·kg(-1). Propofol was administered via a target-controlled infusion (TCI) system (Diprifusor™) set at an effect-site concentration of 5 μg·mL(-1). Fentanyl was given by a TCI system using the STANPUMP software (Schafer model). The concentration for the first patient was set at 3 ng·mL(-1) and modified in each group according to the up-down method. Skin incision was performed after more than ten minutes equilibration time. Serum fentanyl concentration, bispectral index (BIS), and hemodynamic parameters were measured two minutes before and after skin incision. The Cp50incision of fentanyl was derived from the mean of the crossovers (i.e., the serum fentanyl concentrations of successive participants who responded and those who did not or vice versa).

RESULTS

Ten and 11 independent crossover pairs were collected in the control and flurbiprofen groups, respectively, representing 42 of 62 enrolled patients. The mean (SD) fentanyl Cp50incision was less in the flurbiprofen group [0.84 (0.63) ng·mL(-1)] than in the control group [1.65 (1.15) ng·mL(-1)]; P = 0.007; however, there were no differences in BIS, blood pressure, or heart rate, between groups.

CONCLUSION

Preoperative flurbiprofen axetil decreased the Cp50incision of fentanyl by 49% during propofol anesthesia without changing the BIS or hemodynamic variables.

[A patient with congenital antithrombin III deficiency who underwent laparoscopic renal resection]

A 66-year-old man with congenital antithrombin III (ATIII) deficiency was scheduled to undergo laparoscopic renal resection. On admission the plasma ATIII activity was as low as 56%. After giving ATIII intravenously, the plasma ATIII activity increased to 103% on the day of surgery. It is usually difficult to monitor ATIII during surgery. Instead, we measured activated clotting times (ACTs). The ACT before operation was 178 seconds. During the operation, the ACT dropped to 81 seconds. We administered 3,000 units of heparin, and the ACT increased to 182 seconds. After surgery, the plasma ATIII activity was 68%. We managed the ACT activity to a target value of 100% postoperatively, until the patient was switched from heparin to oral warfarin. He was discharged without complications 10 days after surgery. In this patient, the ACT decreased during the operation, as did the ATIII activity. Although the half-life of the ATIII preparation was 3 days, it appeared that the ATIII activity, which was high preoperatively, decreased during the operation. Coagulation abnormalities could be managed quickly by measuring ACT. Our results suggest that the measurement of ACT is an effective technique for the intraoperative monitoring of patients with congenital ATIII deficiency.

Reappearance of circulating heparin in whole blood heparin concentration-based management does not correlate with postoperative bleeding after cardiac surgery

OBJECTIVE

The Hepcon Heparin Management System (HMS) facilitates administration of higher heparin and lower protamine doses, which may affect bleeding potential due to heparin rebound. The present study evaluated heparin rebound in patients for whom the Hepcon HMS was used to determine whether point-of-care tests detect residual heparin and residual heparin is associated with postoperative blood loss.

DESIGN

Prospective study.

SETTING

Tertiary care center affiliated with a university hospital.

PARTICIPANTS

Adults undergoing elective cardiac surgery requiring cardiopulmonary bypass.

INTERVENTIONS

In blood samples obtained at baseline, at 2 minutes, and at 1, 2, 4, 6, and 24 hours after heparin neutralization, heparin concentrations were measured using an automated chromogenic assay. Activated coagulation time (ACT), activated partial thromboplastin time (APTT), and thromboelastometry 2 hours after heparin neutralization also were examined in the last 22 study patients enrolled.

MEASUREMENTS AND MAIN RESULTS

All 31 patients had measurable heparin levels 2 hours after protamine administration; 22 patients exhibited a primary failure to reverse heparin after protamine administration, and 9 patients had measureable heparin levels 2 hours after complete heparin reversal (ie, heparin rebound). The thromboelastometric variable, INTEM-CT:HEPTEM-CT ratio, correlated with heparin concentration (r=0.72), but ACT (r=-0.12), APTT (r=0.36), and whole blood heparin concentration, determined using the Hepcon HMS, did not. Peak heparin concentration (0.18±0.07 U/mL) at 4 hours was not correlated with mediastinal blood loss.

CONCLUSION

Circulating heparin detected by the chromogenic assay was too low to be clinically significant based on postoperative bleeding, although all 31 patients had residual heparin or heparin rebound at 2 hours after protamine administration with use of the Hepcon HMS.

[A case of postoperative convulsive seizure following tranexamic acid infusion during aortic valve replacement]

We present a case of postoperative convulsive seizure in an 84-year-old man who underwent an aortic valve replacement. The patient had hypertension associated with hyperaldosteronism and chronic interstitial nephritis. The duration of cardiopulmonary bypass was 74 min. A generalized seizure lasting approximately 1 minute occurred at 1 hour after the patient's arrival in the intensive care unit. A total of 9 generalized seizures, which were aborted by the intravenous administration of diazepam (5 mg), occurred every 30 min. For seizure control, the continuous administration of midazolam (2 mg x hr(-1)) was initiated. On the day after the discontinuation of the midazolam, a generalized seizure recurred and an infusion of sodium thiopental was started. No further seizures were observed. On the sixth postoperative day, the patient was extubated and discharged without any neurological abnormalities. Imaging showed old small areas of cerebral infarction in the basal ganglia, which were not thought to have contributed to the seizures. The blood sugar, sodium, and calcium levels were within the normal limits. The seizures were likely due to a total dose of 8 g of tranexamic acid (TXA) administered intraoperatively. Possible mechanisms of TXA-induced seizures include blockage of inhibitory cortical y -aminobutyric acid-A receptors.

[The correlation of middle ear pressure variations with mastoid pneumatization during nitrous oxide administration]

BACKGROUND

The present study evaluated the relationship between the middle ear (ME) pressure increase rate (PIR) and the mastoid size as well as the effect of mastoid size on the incidence of nausea and vomiting during nitrous oxide (N2O) anesthesia.

METHODS

Twelve healthy male volunteers were recruited. The extent of mastoid pneumatization was measured planimetrically using a mastoid X-ray (Schuller's view). The ears were then divided into a small or large mastoid group according to the median value. The ME pressure was compared just before each increase to 33%, 50%, and 67% N2O. Using the ME pressure curve, the PIR for the first peak of the curve steepness was calculated.

RESULTS

Increasing the end-tidal N2O concentration to 50% and 67% in the large mastoid group and to 33%, 50%, and 67% in the small mastoid group significantly increased the ME pressure. The PIR in the ears in the large mastoid group was significantly lower and the incidence of nausea was 33% in the small mastoid group during 33% N2O anesthesia.

CONCLUSIONS

A higher PIR in the ears and a higher incidence of nausea were observed in the small mastoid group, compared with the large mastoid group.

Scattered radiation from dental metallic crowns in head and neck radiotherapy

We aimed to estimate the scattered radiation from dental metallic crowns during head and neck radiotherapy by irradiating a jaw phantom with external photon beams. The phantom was composed of a dental metallic plate and hydroxyapatite embedded in polymethyl methacrylate. We used radiochromic film measurement and Monte Carlo simulation to calculate the radiation dose and dose distribution inside the phantom. To estimate dose variations in scattered radiation under different clinical situations, we altered the incident energy, field size, plate thickness, plate depth and plate material. The simulation results indicated that the dose at the incident side of the metallic dental plate was approximately 140% of that without the plate. The differences between dose distributions calculated with the radiation treatment-planning system (TPS) algorithms and the data simulation, except around the dental metallic plate, were 3% for a 4 MV photon beam. Therefore, we should carefully consider the dose distribution around dental metallic crowns determined by a TPS.

[Prolonged hoarseness and arytenoid dislocation after endotracheal intubation]

We present a case of prolonged hoarseness after tracheal intubation in a 62-year-old woman with bronchial asthma who underwent a pylorogastrectomy under a combination of epidural and general anesthesia. After the induction of anesthesia, the patient was carefully intubated using a 7.5-mm cuffed endotracheal tube without a stylet to avoid causing an asthma attack; the patient was extubated approximately 6 hours after the tracheal intubation. On the first postoperative day, the patient complained of hoarseness, vocal fatigue, and dysphagia. A direct laryngoscopy performed by an otorhinolaryngologist revealed dyskinesia of the left vocal cord and sufficient arytenoid cartilage mobility. The poor vocal fold mobility was probably caused by the force exerted on the left arytenoid by the convex curvature of the endotracheal tube, which had been inserted from the right side of the mouth, or a backward pressure on the thyroid cartilage during intubation. Early treatment is crucial in such cases, since the cricoarytenoid joint can become fibrosed in an unfavorable position. Fortunately, all the symptoms disappeared after one month in the present case. Although the trigger responsible for the spontaneous healing remains unknown, natural recovery might be associated with proper use of the vocal cords.

The role of inhibitor of DNA-binding (Id1) in hyperproliferation of keratinocytes: the pathological basis for middle ear cholesteatoma from chronic otitis media

OBJECTIVES

A hallmark of cholesteatoma is hyperproliferation of keratinocytes with abundant production of keratins in the middle ear under chronic inflammatory conditions. However, little is known about the driving force of cellular proliferation and keratin production of cholesteatomal matrix. The purpose of this study was to investigate the cellular proliferation and keratin production of keratinocytes under the influence of Id1, a candidate transcription factor to cell proliferation.

MATERIALS AND METHODS

Keratinocytes were transfected with Id1 and the responses of keratinocytes to Id1 were studied by using cellular and molecular biologic methods.

RESULTS

Id1 positively contributed to the cell cycle progression and negatively to the p16(Ink4a) downregulation via the nuclear factor-kappa B (NF-κB)/cyclin D1 pathway. Id1 significantly increased the promoter activity of NF-κB which, in turn, up-regulated the expression of cyclin D1 and keratin 10 in keratinocytes. Specific NF-κB inhibitors (pyrrolidine dithiocarbamate, PDTC), or dominant-negative inhibitor (I kappa B alpha mutant, IκBαM) abrogated the Id1-induced cell proliferation and keratin 10 production whereas p65, a subunit of the NF-κB heterodimer and an enhancer of the NF-κB activity, strengthened the Id1-induced cell proliferation and keratin 10 production.

CONCLUSIONS

Id1 contributed to hyperproliferation of keratinocytes via enhancement of cell cycle progression, removal of cell cycle inhibition, and simultaneously increased keratin production.

High-rate hydrogenotrophic denitrification in a fluidized-bed biofilm reactor using solid-polymer-electrolyte membrane electrode (SPEME)

A fluidized-bed biofilm reactor equipped with a Solid-Polymer-Electrolyte Membrane Electrode (SPEME) cell was developed in order to enhance hydrogenotrophic denitrification of groundwater. Porous cubes made of polyvinylalcohol (PVA) were used as a biofilm carrier and continuous treatments using synthetic groundwater were carried out for 105 days. Electric current was changed step-wise from 0.4 to 4.0 A. Experimental results showed that efficient production and dissolution of hydrogen were achieved by application of electric current as well as high-rate denitrification simultaneously. Denitrification rates of nitrite increased with the increase of electric current. Overall denitrification rates attained to about 90 mg-N/L/h, which was 3 to 9 times as high as those reported in former studies. Supplying electric current of about two times of stoichiometric equivalent to the cell considered necessary for complete denitrification. Water quality in effluent was very stable and electrolytic voltage was low around 3 V. In addition, simple and secure operation was demonstrated over the experiment. From these results, it was concluded that the present fluidized-bed biofilm reactor equipped with a SPEME cell could be very feasible for high-rate hydrogenotrophic denitrification of ground water.

Permissive range of hypercapnia for improved peripheral microcirculation and cardiac output in rabbits*

OBJECTIVES

Permissive hypercapnia improves outcomes in patients with respiratory failure, most likely because of a reduction in ventilator-induced lung injury. Because hypercapnia is a potent vasoactive stimulus, adequate tissue perfusion and oxygen delivery to dilated microvessels may be restored. We examined how Paco2 affects microvascular changes, hemodynamics, and cardiac output in rabbits. We evaluated the permissive range of Paco2 required for maintenance of the peripheral circulation.

DESIGN

Prospective experimental animal study.

SETTING

Animal research laboratory.

SUBJECTS

A total of 31 Japanese domestic white rabbits.

INTERVENTIONS

The animals were anesthetized with pentobarbital. An ear chamber was prepared to examine blood vessels by intravital microscopy. The rabbits were mechanically ventilated with air, oxygen, and CO2. The values of Paco2 were adjusted to about 20 (hypocapnia), 40 (normocapnia), 60, 80, 100, 125, 150, and >250 mm Hg (hypercapnia). After stabilization at each Paco2 level, microvascular changes were recorded with a microscope-closed video camera to permit analysis of arteriolar diameter and blood flow.

MEASUREMENTS AND MAIN RESULTS

The pH and heart rate decreased and mean blood pressure increased progressively as the Paco2 was increased. When Paco2 was increased from 20 to 80 mm Hg, vessel diameter, blood-flow velocity, and blood-flow rate increased markedly. Cardiac output increased slightly. When Paco2 exceeded 100 mm Hg, all of these variables decreased. When Paco2 exceeded 150 mm Hg, all variables were significantly lower than the control values (p < .01).

CONCLUSION

Intravital microscopic visualization of the rabbit ear microcirculation showed that 150 mm Hg is the permissive upper limit of acute hypercapnia with respect to maintenance of the peripheral microcirculation.

Different profiles of IL-10+IFN-gamma-IL-4-CD4+ T cells in the peripheral blood in atopic and non-atopic asthmatics

BACKGROUND

The impaired production of interleukin (IL) 10 from regulatory T cells has been proposed as a causal mechanism of asthma. Although IL-10-producing (IL-10+) T cells are detectable in the peripheral blood, their significance in the pathophysiology of asthma remains uncertain.

OBJECTIVES

This study aimed to investigate the profile of circulating IL-10+CD4+ T cells in atopic and non-atopic asthma.

METHODS

Atopic and non-atopic asthmatics were divided into a mild and severe group. Their peripheral blood mononuclear cells (PBMCs) were stimulated with anti-CD3 and anti-CD28 antibodies and then processed for triple cytokine flow cytometry directed to IL-10, interferon (IFN) gamma and IL-4.

RESULTS

IL-10+CD4+ cells were exclusively detected in the IFN-gamma-IL-4- population. In atopic asthma, the frequency of IL-10+IFN-gamma-IL-4-CD4+ cells in the severe group was significantly lower than that in the mild group. The frequency of IL-10+IFN-gamma-IL-4-CD4+ cells in the severe group was not significantly different from that in the mild group of those with non-atopic asthma. The frequency of IL-4+IFN-gamma-IL-10-CD4+ cells (Th2) was significantly higher in the group with mild atopic asthma than in that with mild non-atopic asthma. IFN-gamma+IL-4-IL-10-CD4+ cells (Th1) did not differ between groups, irrespective whether the subjects suffered from atopic or non-atopic asthma.

CONCLUSIONS

IL-10+CD4+ cells in PBMCs may be distinct from Th1 or Th2 and likely have the profile of regulatory T cells. The differential association of IL-10+IFN-gamma-IL-4-CD4+ cells with clinical severity between atopic and non-atopic asthma implies that its pathophysiological significance may differ among asthma phenotypes.

A woman who required long-term mechanical ventilation to treat limbic encephalitis during pregnancy

We describe our experience with a woman who had severe non-herpetic acute limbic encephalitis at 20 weeks' gestation. Despite receiving mechanical ventilation for about 3 months because of impaired consciousness and frequent convulsions, she had a normal delivery and an uneventful recovery with no sequelae. The patient did not respond to treatment with antiviral agents. Anticonvulsant agents were given while monitoring plasma drug concentrations. Early treatment and the prevention of complications apparently contributed to good outcomes in the mother and child.

EFFECTS OF COLLOID RESUSCITATION ON PERIPHERAL MICROCIRCULATION, HEMODYNAMICS, AND COLLOIDAL OSMOTIC PRESSURE DURING ACUTE SEVERE HEMORRHAGE IN RABBITS

We examined the effects of hydroxyethyl starch (HES) on the microcirculation, hemodynamics, and colloidal osmotic pressure in a rabbit model of hemorrhagic shock. A total of 40 rabbits was anesthetized with pentobarbital and isoflurane, and they were mechanically ventilated. An ear chamber was prepared to examine blood vessels by intravital microscopy. Shock was induced by removing nearly half of the circulating blood volume. Twenty rabbits received 20 mL of HES by intravenous infusion immediately after blood letting. Additional HES was then administered intravenously to a total volume of 100 mL. The other 20 rabbits (control) were intravenously given 40 mL of lactated Ringer's solution (LR), followed by additional LR to a total volume of 200 mL, administered under the same conditions as HES. After blood letting, arteriolar diameter decreased similarly in the the HES and LR groups (HES, 40.5% +/- 14.8% of the baseline value versus LR, 43.3% +/- 13.1%). After the completion of infusion, arteriolar diameter significantly recovered to 90.8% +/- 10.2% of the baseline value in the HES group as compared with only 62.6% +/- 10.7% in the LR group (P < 0.005). Recovery of arterial blood flow velocity and blood flow rate was also significantly better in the HES group than in the LR group (P < 0.005). Mean arteriolar pressure, central venous pressure, and plasma colloid osmotic pressure after the completion of infusion were significantly greater in the HES group than in the LR group (P < 0.005). We conclude that intravenous infusion of HES effectively maintains the microcirculation, hemodynamics, and colloidal osmotic pressure in a rabbit model of acute severe hemorrhage.

A Single Local Application of Recombinant Human Basic Fibroblast Growth Factor Accelerates Initial Angiogenesis During Wound Healing in Rabbit Ear Chamber

Local angiogenic therapy with recombinant human basic fibroblast growth factor (rhbFGF) has been used to promote wound healing. To obtain useful information for the development of optimal angiogenic therapy, we chronologically evaluated the effects of a single local application of rhbFGF on angiogenesis in a rabbit ear chamber model of wound healing by observing the subcutaneous vessel bed intravitally. New vessel formation during wound healing was macroscopically and microscopically evaluated for 5 wk. Each rabbit ear chamber received a single dose of 6 microg rhbFGF (treatment B1: n = 13), 18 microg rhbFGF (treatment B2: n = 16), or physiological saline as control (n = 13). At 1 wk the newly vascularized area was significantly larger in groups B1 and B2 than in control. At 2 wk, the vascularized areas in groups B1, B2, and control were similar. At 5 wk, the percentage of rabbits with complete vascularization was significantly larger in group B1 than in control. Capillary density at 5 wk was similar among the three groups. These results suggest that locally applied rhbFGF accelerated angiogenesis during early wound healing in rabbits; however, this effect was transient and no increase in capillary density occurred at the completion of vascularization.

The LET spectra at different penetration depths along secondary9C and11C beams

Owing to the potentially therapeutic enhancement of delayed particles in treating malignant diseases by radioactive 9C-ion beam, LET spectra at different penetration depths for a 9C beam with 5% momentum spread, produced in the secondary beam line (SBL) at HIMAC, were measured with a multi-wire parallel-plate proportional counter. To compare these LET spectra with those of a therapeutic 12C beam under similar conditions, the 12C beam was replaced with an 11C beam, yielded in the SBL as well and having almost the same range as that of the 9C beam. The LET spectra of the 9C beam and its counterpart, i.e. the 11C beam, at various depths were compared, especially around the Bragg peak regions. The results show that nearby the Bragg peak lower LET components decreased in the LET spectra of the 9C beam while extra components between the LET peak caused by the primary beam and the lower components due to the fragments could be observed. These additional contributions in the LET spectra could be attributed to parts of the emitted particles from the radioactive 9C ions with suitable conditions regarding the LET counter. Integrating these LET spectra in different manners, depth-dose and dose-averaged LET distributions were obtained for the 9C and 11C beams, forming the basic data sets for further studies. In general, the depth-dose distributions of the 9C and 11C beams are comparative, i.e. almost the same peak-to-plateau ratio. The ratio for the 9C beam, however, has room to increase due to the geometric structure limitation of the present detector. The dose-averaged LETs along the beam penetration are always lower for the 9C beam than for the 11C beam except at the falloff region beyond the Bragg peak. Applying the present depth-dose and dose-averaged LET data sets as well as the essential radiobiological parameters obtained with 12C beams previously for HSG cells, an estimate concerning the HSG cell surviving effects along the penetration of the 9C and 11C beams shows that lower survival fractions for the 9C beam at the distal part of the Bragg peak, corresponding to the stopping region of the incoming 9C ions, can be expected when the same entrance dose is given. It is still hard to appreciate the potential of 9C beams in cancer therapy based on the present LET spectrum measurement, but it provides a substantial basis for upcoming radiobiological experiments.