Impact of wound management strategies after revascularization for chronic limb-threatening ischemia

OBJECTIVE

There is no established consensus or guidelines for wound management after revascularization for patients with chronic limb-threatening ischemia (CLTI) without severe infection. This study is designed to evaluate the clinical effect of the wound management strategy on toe wounds after revascularization for CLTI.

METHODS

This retrospective cohort study was performed at eight institutions affiliated with Keio University School of Medicine in Japan and included 261 patients who underwent revascularization for CLTI between April 2019 and July 2021. We identified 132 patients with toe wounds from the database who had restored in-line blood flow to the foot. Patients were divided into two groups by the timing of toe resection after revascularization, which dictated the wound management policy. Group A (62 patients) underwent early toe amputation for suspected osteomyelitis, whereas group B (70 patients) underwent watchful waiting. The primary outcome was wound healing after revascularization; the secondary outcome was major amputation. We compared outcomes between groups A and B after propensity score matching.

RESULTS

Using propensity score matching, each patient in group A (33 patients) was matched with a patient in group B (33 patients). Wound healing in matched group A was significantly better than that in matched group B (respectively: 1-year wound healing rate: 90.0% vs 68.2%, P < .001; median wound healing time: 65 days vs 258 days, P < .01). Although five major amputations were necessary in matched group B, none were required in matched group A (P = .05). The high rate of major amputations in group B was attributed to the sudden exacerbation of infection. Limb salvage rate in matched group A exceeded matched group B (100.0% vs 90.5%: 1-year limb salvage rate, P = .02).

CONCLUSIONS

Early toe amputation for highly suspected osteomyelitis in patients with CLTI with toe wounds may expedite wound healing compared with watchful waiting, potentially avoiding unnecessary major amputation. Considering the wound management strategy is crucial when evaluating wound healing outcomes in patients with CLTI with revascularization.

An analog-AI chip for energy-efficient speech recognition and transcription

Models of artificial intelligence (AI) that have billions of parameters can achieve high accuracy across a range of tasks1,2, but they exacerbate the poor energy efficiency of conventional general-purpose processors, such as graphics processing units or central processing units. Analog in-memory computing (analog-AI)3-7 can provide better energy efficiency by performing matrix-vector multiplications in parallel on 'memory tiles'. However, analog-AI has yet to demonstrate software-equivalent (SWeq) accuracy on models that require many such tiles and efficient communication of neural-network activations between the tiles. Here we present an analog-AI chip that combines 35 million phase-change memory devices across 34 tiles, massively parallel inter-tile communication and analog, low-power peripheral circuitry that can achieve up to 12.4 tera-operations per second per watt (TOPS/W) chip-sustained performance. We demonstrate fully end-to-end SWeq accuracy for a small keyword-spotting network and near-SWeq accuracy on the much larger MLPerf8 recurrent neural-network transducer (RNNT), with more than 45 million weights mapped onto more than 140 million phase-change memory devices across five chips.

Search for the Majorana Nature of Neutrinos in the Inverted Mass Ordering Region with KamLAND-Zen

The KamLAND-Zen experiment has provided stringent constraints on the neutrinoless double-beta (0νββ) decay half-life in ^{136}Xe using a xenon-loaded liquid scintillator. We report an improved search using an upgraded detector with almost double the amount of xenon and an ultralow radioactivity container, corresponding to an exposure of 970 kg yr of ^{136}Xe. These new data provide valuable insight into backgrounds, especially from cosmic muon spallation of xenon, and have required the use of novel background rejection techniques. We obtain a lower limit for the 0νββ decay half-life of T_{1/2}^{0ν}>2.3×10^{26}  yr at 90% C.L., corresponding to upper limits on the effective Majorana neutrino mass of 36-156 meV using commonly adopted nuclear matrix element calculations.

Penetration of MeV electrons into the mesosphere accompanying pulsating aurorae

Pulsating aurorae (PsA) are caused by the intermittent precipitations of magnetospheric electrons (energies of a few keV to a few tens of keV) through wave-particle interactions, thereby depositing most of their energy at altitudes ~ 100 km. However, the maximum energy of precipitated electrons and its impacts on the atmosphere are unknown. Herein, we report unique observations by the European Incoherent Scatter (EISCAT) radar showing electron precipitations ranging from a few hundred keV to a few MeV during a PsA associated with a weak geomagnetic storm. Simultaneously, the Arase spacecraft has observed intense whistler-mode chorus waves at the conjugate location along magnetic field lines. A computer simulation based on the EISCAT observations shows immediate catalytic ozone depletion at the mesospheric altitudes. Since PsA occurs frequently, often in daily basis, and extends its impact over large MLT areas, we anticipate that the PsA possesses a significant forcing to the mesospheric ozone chemistry in high latitudes through high energy electron precipitations. Therefore, the generation of PsA results in the depletion of mesospheric ozone through high-energy electron precipitations caused by whistler-mode chorus waves, which are similar to the well-known effect due to solar energetic protons triggered by solar flares.

Incidence, diagnosis and treatment of popliteal artery entrapment syndrome in current vascular practice in Japan

Few data regarding popliteal artery entrapment syndrome (PAES) is available in Japan. In this study, we investigated incidence, diagnosis and treatment of PAES in current vascular practice. A retrospective analysis of all patients with PAES visiting 31 participating institutes between 2003 and 2015 was conducted. Thirty-five limbs (28 patients) were identified during the 13-year study period, and the incidence of PAES was 0.12% of all peripheral artery disease cases revascularized. Mean age was 32.0 ± 16.9 years old, and 60 and more years old was 10.7%. Also, 92.9% were male and 39.3% were athletes. Most frequent initial symptoms were intermittent claudication in 23 limbs (65.7%); 4 limbs (11.4%) had chronic limb-threatening ischemia. CT scan was most frequently (94.3%) used for the diagnostic imaging followed by MRI (45.7%) and duplex ultrasound (45.7%). Stress test such as dorsal flexion during duplex ultrasound was used only in 28.6%. Thirty-two limbs (91.4%) received surgical treatment, including 23 arterial reconstructions (71.9%); there were no major perioperative complications. All patients achieved improvement of their symptoms, and the average ankle brachial index increased from 0.69 ± 0.22 to 1.00 ± 0.14 post-surgery. The average postoperative follow-up period was 26.0 months with only one reintervention during the follow-up. In conclusion, PAES was a rare condition and traditional surgical treatment was solid. However, given a broad spectrum of clinical feature of PAES and less usage of diagnostic duplex ultrasound with stress test, there might be a miss- or delayed diagnosis of PAES even in the current vascular practice.

Multiple time-scale beats in aurora: precise orchestration via magnetospheric chorus waves

The brightness of aurorae in Earth’s polar region often beats with periods ranging from sub-second to a few tens of a second. Past observations showed that the beat of the aurora is composed of a superposition of two independent periodicities that co-exist hierarchically. However, the origin of such multiple time-scale beats in aurora remains poorly understood due to a lack of measurements with sufficiently high temporal resolution. By coordinating experiments using ultrafast auroral imagers deployed in the Arctic with the newly-launched magnetospheric satellite Arase, we succeeded in identifying an excellent agreement between the beats in aurorae and intensity modulations of natural electromagnetic waves in space called “chorus”. In particular, sub-second scintillations of aurorae are precisely controlled by fine-scale chirping rhythms in chorus. The observation of this striking correlation demonstrates that resonant interaction between energetic electrons and chorus waves in magnetospheres orchestrates the complex behavior of aurora on Earth and other magnetized planets.

A very low diffusion Fricke gel dosimeter with functionalised xylenol orange-PVA (XOPVA)

A gel dosimeter has been developed utilising a recently reported system for reducing Fe³⁺ diffusion in a Fricke gel dosimeter which chelates xylenol orange to the gelling agent poly(vinyl alcohol) (PVA). Formulations were investigated using both gelatin and PVA as the gelling agent, along with the inclusion of glyoxal. The resulting gel had an optical density dose response of 0.0031 Gy^-1, an auto-oxidation rate of 0.000 23 h^-1, and a diffusion rate of 0.132 mm² h^-1 which is a significant improvement over previously reported gelatin based Fricke gel dosimeters. The gel was also shown to be energy and dose-rate independent and could be reused after irradiation. Thus, this gel dosimeter has the potential to provide a safe and practical solution to three dimensional radiation dosimetry in the medical environment.

P5594Comparison of non-vitamin K antagonist oral anticoagulants versus vitamin K antagonist on changes in pulmonary vascular resistance in patients with chronic thromboembolic pulmonary hypertension

Background/Introduction

Chronic thromboembolic pulmonary hypertension (CTEPH) requires a lifelong anticoagulation therapy. However, the efficacy or safety of non-vitamin K antagonist oral anticoagulants (NOACs) have not been established in CTEPH.

Purpose

We aimed to evaluate the effects of NOACs on the changes in pulmonary vascular resistance (PVR) and their adverse events such as bleeding and clinical worsening in CTEPH.

Methods

We retrospectively compared the changes in PVR among CTEPH patients taking vitamin-K antagonists (VKA) (n=38) and those taking NOACs (n=46) to evaluate the effectiveness of NOACs for the prophylaxis of thrombotic disease progression in CTEPH. Also, we extracted incidence of clinically relevant bleeding and clinical worsening in CTEPH as an exploratory outcome measures. Clinical worsening in CTEPH was defined as composite outcome of death from any cause, lung transplantation and worsening pulmonary hypertension that resulted in hospitalization, addition of specific drug for pulmonary hypertension, or rescue pulmonary endarterectomy or balloon pulmonary angioplasty. Clinically relevant bleeding was defined as composite major bleeding and/or clinically relevant non-major bleeding, which is defined as bleeding associated with the need for medical intervention, contact with a physician, interruption of anticoagulation therapy, discomfort or impairment of activities of daily life.

Results

The changes in PVR (VKA group; −0.17±0.82 woods unit/year, NOACs group; −0.44±0.89 woods unit/year, p=0.32) were comparable between VKA and NOACs groups. The incidence of clinical worsening in CTEPH (VKA group; 1.8% per patient-year, NOACs group; 0% per patient-year) and clinically relevant bleeding (VKA group; 2.8% per patient-year, NOACs group; 2.8% per patient-year) was comparable between the VKA and NOACs groups. D-dimer levels (VKA group; 0.58±0.22 μg/ml, NOACs group; 0.67±0.47 μg/ml, p=0.41) were also comparable between the groups.

Conclusions

Our study revealed that NOACs had a similar effectiveness in the prevention of thrombotic disease progression in CTEPH as compared with VKA. The result suggest that NOACs might have similar efficacy and safety as VKA in daily clinical practice.

Acknowledgement/Funding

Japan Agency for Medical Research and Development

P4677Balloon pulmonary angioplasty improves pulmonary arterial compliance in patients with inoperable chronic thromboembolic pulmonary hypertension

Background

Right ventricular (RV) pressure overload is directly related to the increase in mortality in pulmonary hypertension. Pulmonary arterial compliance (CPA; stroke volume/pulmonary pulse pressure) was reported to be an independent determinant of RV systolic afterload in patients with pulmonary arterial hypertension (PAH). Recently, balloon pulmonary angioplasty (BPA) has been reported to reduce mean pulmonary artery pressure (mPAP) and pulmonary vascular resistance (RPA) in patients with inoperable chronic thromboembolic pulmonary hypertension (CTEPH). However, the effects of BPA on CPA remain unclear.

Purpose

The aim of this study was to investigate the impact of BPA on CPA in patients with inoperable CTEPH.

Methods

We retrospectively analyzed 78 patients (388 BPA sessions) with inoperable CTEPH who underwent BPA in our hospital from September 2012 to June 2018. Total number of BPA sessions was 5.0±1.8 (range 1–10). The pressure values were obtained from right heart catheterization at baseline (n=78), just after the final BPA (n=78) and follow-up (n=19) periods. The intervals from baseline to the final BPA and the final BPA to follow-up were 593±498 days and 397±276 days, respectively.

Results

Mean age was 60.5±12.6 years old, and 64 (82%) were female. All patients were symptomatic (WHO functional class II/III/IV 16/55/7). Patients who had pulmonary vasodilators decreased from 70 (90%) at baseline to 23 (28%) at the final BPA and 2 (15%) at follow-up. BPA reduced mPAP and RPA significantly from baseline to the final BPA and follow-up periods. BPA also improved CPA with significant reduction of pulse pressure despite no significant changes in stroke volume between baseline and follow-up (Table). CPA between the final BPA and follow-up was equivalent (p=0.95).

Conclusions

BPA improved CPA just after the final BPA in inoperable CTEPH patients. In addition, CPA was preserved during the follow-up after the final BPA sessions. These data suggest that BPA consistently unloads RV systolic afterload in those patients.

Precision Analysis of the ^{136}Xe Two-Neutrino ββ Spectrum in KamLAND-Zen and Its Impact on the Quenching of Nuclear Matrix Elements

We present a precision analysis of the ^{136}Xe two-neutrino ββ electron spectrum above 0.8 MeV, based on high-statistics data obtained with the KamLAND-Zen experiment. An improved formalism for the two-neutrino ββ rate allows us to measure the ratio of the leading and subleading 2νββ nuclear matrix elements (NMEs), ξ_{31}^{2ν}=-0.26_{-0.25}^{+0.31}. Theoretical predictions from the nuclear shell model and the majority of the quasiparticle random-phase approximation (QRPA) calculations are consistent with the experimental limit. However, part of the ξ_{31}^{2ν} range allowed by the QRPA is excluded by the present measurement at the 90% confidence level. Our analysis reveals that predicted ξ_{31}^{2ν} values are sensitive to the quenching of NMEs and the competing contributions from low- and high-energy states in the intermediate nucleus. Because these aspects are also at play in neutrinoless ββ decay, ξ_{31}^{2ν} provides new insights toward reliable neutrinoless ββ NMEs.

Role of red blood cells in the anemia-associated bleeding under high shear conditions

BACKGROUND

Red blood cells (RBCs) contribute to hemostasis under blood-flow, and anemia might contribute to a hemorrhagic diathesis. The majority of current laboratory techniques to assess hemostasis do not consider the effects of RBCs. An assay to determine the role of RBCs in hemostasis could be beneficial for clinical management.

OBJECTIVES

To investigate the influence of RBCs in hemostasis.

METHODS

Hemostasis was investigated using a novel microchip flow-chamber system (T-TAS^® ) in an anemic patient with von Willebrand disease. Subsequently, the effects of RBCs in total thrombus analysis system (T-TAS) were examined using reconstituted whole blood at various hematocrit levels.

RESULTS

In vivo: When the patient was anemic and demonstrated persisted hemorrhagic symptoms despite the maintained adequate von Willebrand factor ristocetin cofactor activity levels, thrombus formation determined by T-TAS was delayed. However, transfusions of RBCs resolved bleeding symptom and, accordingly, the thrombus formation in T-TAS improved. In vitro: Thrombus formation determined by T-TAS at 1000 s^-1 was dose-dependent on hematocrit (the time to reach 10 kPa (T₁₀ ): 10.0 ± 0, 9.5 ± 1.4, 6.7 ± 2.4, 2.8 ± 1.6 min at hematocrits of 0%, 12.5%, 25% and 50%, respectively). Markedly defective thrombus formation (T₁₀ >10 min) was confirmed at a hematocrit <25% at 2000 s^-1 .

CONCLUSION

Red blood cells play an essential role in hemostasis under high shear, and RBC transfusions could be effective for refractory bleeding in patients with anemia. T-TAS measurements appear to reflect the hemostatic consequences of diminished red cell numbers under blood-flow, and could provide a valuable means for monitoring patients.

Technical Note: Preliminary investigations into the use of a functionalised polymer to reduce diffusion in Fricke gel dosimeters

PURPOSE

A modification of the existing PVA-FX hydrogel has been made to investigate the use of a functionalised polymer in a Fricke gel dosimetry system to decrease Fe(3+) diffusion.

METHODS

The chelating agent, xylenol orange, was chemically bonded to the gelling agent, polyvinyl alcohol (PVA) to create xylenol orange functionalised PVA (XO-PVA). A gel was created from the XO-PVA (20% w/v) with ferrous sulfate (0.4 mM) and sulfuric acid (50 mM).

RESULTS

This resulted in an optical density dose sensitivity of 0.014 Gy(-1), an auto-oxidation rate of 0.0005 h(-1), and a diffusion rate of 0.129 mm(2) h(-1); an 8% reduction compared to the original PVA-FX gel, which in practical terms adds approximately 1 h to the time span between irradiation and accurate read-out.

CONCLUSIONS

Because this initial method of chemically bonding xylenol orange to polyvinyl alcohol has inherently low conversion, the improvement on existing gel systems is minimal when compared to the drawbacks. More efficient methods of functionalising polyvinyl alcohol with xylenol orange must be developed for this system to gain clinical relevance.

Measurement of residual platelet thrombogenicity under arterial shear conditions in cerebrovascular disease patients receiving antiplatelet therapy

Essentials A consensus methodology for assessing the effects of antiplatelet agents has not been established. Measuring platelet thrombus formation (PTF) for evaluating antiplatelet effects was assessed. PTF differentially reflected antiplatelet effects compared to other tests. PTF may be associated with the severity of carotid or intracranial arterial stenosis. Click to hear a presentation on platelet function testing in the clinic by Gresele and colleagues

SUMMARY

Background A consensus methodology for assessing the effects of antiplatelet agents has not been established. Objective We investigated the usefulness of directly measuring platelet thrombus formation (PTF) using a microchip-based flow chamber system for evaluating antiplatelet therapy. Patients/Methods Platelet thrombus formation in the whole blood of 94 patients with ischemic cerebrovascular disease treated with clopidogrel and/or aspirin was measured in a flow chamber system at a shear rate of 1500 s(-1) and was compared with the results of assays for agonist-induced platelet aggregability, phosphorylation of vasodilator-stimulated phosphoprotein, platelet p-selectin expression (PS), and platelet-monocyte complexes. Results In all patients tested, area under the flow pressure curve (AUC10), which represents platelet thrombogenicity, showed weak correlation with platelet aggregation induced by either adenosine diphosphate or collagen. In addition, AUC10 was lower in patients treated with dual antiplatelet therapy (median 79.4) compared with patients treated with aspirin or clopidogrel alone (217.7 and 301.0, respectively), whereas the parameters evaluated by the other assays did not reflect the combined treatment efficacy. In clopidogrel monotherapy patients, AUC10 was associated with the severity of arterial stenosis (R(2) = 0.127, β = 1.25), and AUC10 and PS were higher in patients with severe carotid or intracranial arterial stenosis than in those with mild stenosis. Conclusions Platelet thrombus formation measurement using a flow-chamber system was useful for evaluating the efficacy of treatment with aspirin and clopidogrel, both alone and in combination. The present findings indicate that high residual platelet thrombogenicity in patients treated with clopidogrel may be associated with the severity of carotid or intracranial arterial stenosis.

Usefulness of the Total Thrombus-Formation Analysis System (T-TAS) in the diagnosis and characterization of von Willebrand disease

INTRODUCTION

The heterogeneity of von Willebrand disease (VWD) makes its diagnosis a difficult task.

METHODS

We report here on the usefulness of a microchip-based flow-chamber system, the total thrombus-formation analysis system (T-TAS), in the identification and characterization of VWD. Thirty VWD patients and 20 healthy subjects were studied with the T-TAS platelet (PL) and atherome (AR) microchips developed for the in vitro assessment of platelet thrombus formation and fibrin-rich platelet thrombus formation respectively.

RESULTS

Samples from severe type 1 VWD, characterized by von Willebrand factor (VWF) levels below 10 U dL^-1 , failed to occlude either the PL or the AR chip capillaries, while the occlusion times were normal in patients with mild type 1 VWD (VWF above 25 U dL^-1 ). PL and/or AR chip occlusion occurred, but took longer than normal, for samples from type Vicenza and type 1 VWD patients, whose VWF levels ranged between 10 and 25 U dL^-1 . No PL or AR chip capillary occlusion was seen for samples from patients with type 2A or 2B VWD featuring the absence of large VWF multimers, whereas no abnormalities emerged for type 2B patients with normal multimer patterns.

CONCLUSION

The T-TAS appears to be sensitive mainly to plasma VWF concentration and the presence of large multimers. Failure of the PL and AR chips to become occluded points to a lack of large VWF multimers, or type 1 VWD with VWF levels below 10 U dL^-1 . Although the T-TAS does not assure a precise VWD diagnosis, it does point us in the right direction, and thus seems a useful global preliminary test.

Assessing the clinical severity of type 1 von Willebrand disease patients with a microchip flow-chamber system

BACKGROUND

The clinical phenotype of von Willebrand disease (VWD) is heterogeneous, and von Willebrand factor ristocetin cofactor activity (VWF:RCo) does not always reflect clinical severity, especially in VWD type 1. We have reported the potential of a microchip flow-chamber system (Total-Thrombus Formation Analysis System [T-TAS®]) for assessing physiologic hemostasis in VWD. Aim To evaluate the relationship between T-TAS, bleeding score (BS) and laboratory test results in type 1 VWD patients.

METHODS

Microchips coated with collagen (platelet chip [PL-chip]) or collagen/thromboplastin (AR-chip) were used to assess platelet thrombus formation (PTF) at high shear rates or fibrin-rich PTF at low shear rates, respectively, in whole blood from 50 patients. The times needed for the flow pressure to increase by 10 kPa and 30 kPa (T10 and T30 ) from baseline were calculated from flow pressure curves. BS was determined by the use of a standardized questionnaire.

RESULTS

PL-T10 values correlated with BS (R(2) ~ 0.45) better than VWF:RCo (R(2) ~ 0.36), irrespective of the flow rate, whereas AR-T10 showed only a weak correlation with BS (R(2) ~ 0.18). Patients with PL-T10 > 10 min or AR-T10 > 30 min had lower VWF levels and higher BS than those with PL-T10 ≤ 10 min or AR-T10 ≤ 30 min, and the greatest differences were observed with PL-T10. Clinical severity appeared to correlate best with PL-T10 > 8 min. BS was significantly higher in patients with VWF:RCo of < 10 IU dL(-1) than in those with VWF:RCo of 10 IU dL(-1) to < 25 IU dL(-1) and 25-40 IU dL(-1). In patients with VWF:RCo of < 10 IU dL(-1) , BS was significantly higher in those with PL-T10 > 8 min than in those with PL-T10 ≤ 8 min.

CONCLUSION

T-TAS could be a useful technique for discriminating and predicting BS in VWD type 1 patients.

Search for bosonic superweakly interacting massive dark matter particles with the XMASS-I detector

Bosonic superweakly interacting massive particles (super-WIMPs) are a candidate for warm dark matter. With the absorption of such a boson by a xenon atom, these dark matter candidates would deposit an energy equivalent to their rest mass in the detector. This is the first direct detection experiment exploring the vector super-WIMPs in the mass range between 40 and 120 keV. With the use of 165.9 day of data, no significant excess above background was observed in the fiducial mass of 41 kg. The present limit for the vector super-WIMPs excludes the possibility that such particles constitute all of dark matter. The absence of a signal also provides the most stringent direct constraint on the coupling constant of pseudoscalar super-WIMPs to electrons. The unprecedented sensitivity was achieved exploiting the low background at a level 10(-4)  kg-1 keVee-1 day-1 in the detector.

Successful hyperbaric oxygen therapy for refractory BK virus-associated hemorrhagic cystitis after cord blood transplantation

BK virus-associated hemorrhagic cystitis (BKV-HC) is a common and major cause of morbidity in recipients of allogeneic hematopoietic stem cell transplantation. A 32-year-old woman developed severe BKV-HC on day 24 after cord blood transplantation (CBT). Despite supportive therapies - such as hyperhydration, forced diuresis, and urinary catheterization - macroscopic hematuria and bladder irritation persisted for over a month. Hyperbaric oxygen (HBO) therapy at 2.1 atmospheres for 90 min per day was started on day 64 after CBT. Macroscopic hematuria resolved within a week, and microscopic hematuria was no longer detectable within 2 weeks. Hematuria did not recur after 11 sessions of HBO therapy, and no significant side effects were observed during or after treatment. HBO therapy could thus be useful in controlling refractory BKV-HC after CBT.

Relative incidences and outcomes of Clostridium difficile infection following transplantation of unrelated cord blood, unrelated bone marrow, and related peripheral blood in adult patients: a single institute study

BACKGROUND

Clostridium difficile is a major cause of nosocomial diarrhea. The incidence and prognosis of C. difficile-associated diarrhea (CDAD) has not yet been assessed in adult patients after unrelated cord blood transplantation (uCBT).

METHODS

The medical records of 135 adult unrelated cord blood transplant recipients were reviewed retrospectively to investigate the clinical features of CDAD after uCBT. These data were compared to medical records of 39 unrelated bone marrow transplant recipients and 27 related peripheral blood stem cell transplant recipients as controls.

RESULTS

A total of 17 recipients developed CDAD, with onset occurring at a median of 22 days (range, 0-56 days) after transplantation. Among the unrelated cord blood transplant recipients, 11 (9%) developed CDAD. These results were comparable with those of CDAD after unrelated bone marrow transplantation (uBMT) (2/39, 6%) and related peripheral blood stem cell transplantation (rPBSCT) (4/27, 16%) (P=0.37). Fifteen of the infected recipients were successfully treated with oral metronidazole, vancomycin, or cessation of antibiotics. The remaining 2 recipients who developed CDAD after uCBT died of other causes. The development of CDAD did not negatively affect overall survival after uCBT.

CONCLUSIONS

These data indicate that the incidence and prognosis of CDAD after uCBT are comparable with those after uBMT and rPBSCT.

Carcinoma of the external auditory canal: histological and treatment groups

OBJECTIVE

Evaluation of the clinical and pathological factors associated with the treatment and outcomes of external auditory canal (EAC) carcinomas.

METHODOLOGY

A retrospective review of clinical and pathological analysis was performed on 23 patients who were histologically diagnosed with EAC carcinomas and treated at Hamamatsu University hospital. We evaluated the clinical staging, treatment methods, pathological diagnosis (particularly squamous cell carcinoma, SCC), and patient outcomes. Main outcome measures include staging, treatment procedures, pathological features, and estimated survival rates.

RESULTS

The 5-year overall survival (OS) of study participants was 75.2% and the 10-year OS was 60.2% using the Kaplan-Meier method. The prognosis for SCC was poor compared with other carcinomas (p= 0.0462). The prognoses for SCC patients after treatment with surgery alone and after postoperative radiotherapy or chemoradiotherapy were significantly better than for patients with unresectable tumours (p = 0.0004 and p = 0.0001, respectively). There was no significant difference among the four tumour stage groups. Information about patients' survival status was obtained after a median follow-up period of 57.5 months (range, 7-151 months).

CONCLUSION

Our survival analysis data for carcinoma of the EAC demonstrates that SCC and unresectable cases are associated with poor outcomes. Outcomes for patients with operable disease more closely parallel the survival curves of patients with advanced stage T4 disease. Patients with SCC should be strictly categorized as cases with severe disease.

Time-lapse observation of the dedifferentiation process in mouse chondrocytes using chondrocyte-specific reporters

OBJECTIVE

When chondrocytes prepared from cartilage are expanded in monolayer culture, fibroblast-like cells gradually prevail. Although these prevailing fibroblast-like cells are believed to emerge because of the dedifferentiation of chondrocytes, the definite origin of the prevailing fibroblast-like cells has not been determined. We herein examined whether the prevailing non-chondrocytic cells observed after monolayer expansion culture arise from dedifferentiating chondrocytes or are the result of the overgrowth of fibroblasts that are present at the start of the culture. We also evaluated whether chondrocytes dedifferentiate because they proliferate or because they are cultured in monolayers.

METHODS

Chondrocytes were prepared from Col11a2-EGFP transgenic mice and Col11a2-Cre; R26-stop(flox)-EYFP transgenic mice, which respectively express enhanced green fluorescent protein (EGFP) and Cre specifically in chondrocytes under the control of Col11a2 promoter/enhancer sequences. Col11a2-Cre; R26-stop(flox)-EYFP mice express enhanced yellow fluorescent protein (EYFP) only in cells which express or used to express Cre. We performed a time-lapse observation of the chondrocytes during monolayer expansion culture, and also observed the chondrocytes after treatment with mitomycin C.

RESULTS

A time-lapse observation showed that Col11a2-EGFP chondrocytes underwent cell divisions, lost GFP fluorescence, increased cell numbers, and prevailed during the expansion culture. The observation of the Col11a2-Cre; R26-stop(flox)-EYFP chondrocytes confirmed that most of the cells after expansion in monolayer culture had been chondrocytes. Mitotically inactive chondrocytes generated by treatment with mitomycin C still underwent dedifferentiation, thus suggesting that chondrocyte dedifferentiation is not associated with cell division.

CONCLUSION

The non-chondrocytic cells that prevail after the monolayer expansion culture of chondrocytes originate from chondrocytes, and are not generated by the overgrowth of fibroblasts that are present at the start of the culture. Chondrocyte dedifferentiation does not appear to be associated with cell division.

Glial differentiation of human adipose-derived stem cells: implications for cell-based transplantation therapy

Increasing evidence has shown that adipose-derived stem cells (ASCs) could transdifferentiate into Schwann cell (SC)-like cells to enhance nerve regeneration, suggesting potential new cell-based transplantation therapy for peripheral nerve injuries and neurodegenerative disorders. For the implementation of these results to the clinical setting, it is of great importance to establish the differentiation of human ASCs (hASCs) into a SC phenotype. In this study, we studied hASCs obtained from subcutaneous fat tissue of healthy donors. By a mixture of glial growth factors we differentiated them into Schwann cell-like cells (dhASCs). We then assessed their ability to act as Schwann cells in vitro and in vivo and also compared them with primary human Schwann cells (hSCs). Enzyme-linked immunosorbent assay showed that dhASCs secreted brain-derived neurotrophic factor (BDNF)/nerve growth factor (NGF) at a comparable level, and glial cell-derived neurotrophic factor (GDNF) at a level even higher than hSCs, whereas undifferentiated hASCs (uhASCs) secreted low levels of these neurotrophic factors. In co-culture with NG108-15 neuronal cells we found that both dhASCs and hSCs significantly increased the percentage of cells with neurites, the neurite length, and the number of neurites per neuron, whereas uhASCs increased only the percentage of cells with neurites. Finally, we transplanted green fluorescent protein (GFP)-labeled hASCs into the crushed tibial nerve of athymic nude rats. The transplanted hASCs showed a close association with PGP9.5-positive axons and myelin basic protein (MBP)-positive myelin at 8weeks after transplantation. Quantitative analysis revealed that dhASCs transplantation resulted in significantly improved survival and myelin formation rates (a 7-fold and a 10-fold increase, respectively) as compared with uhASCs transplantation. These findings suggest that hASCs took part in supporting and myelinating regenerating axons, and thus have achieved full glial differentiation in vivo. In conclusion, hASCs can differentiate into SC-like cells that possess a potent capacity to secrete neurotrophic factors as well as to form myelin in vivo. These findings make hASCs an interesting prospect for cell-based transplantation therapy for various peripheral nerve disorders.

Evaluation of a novel flow chamber system to assess clot formation in factor VIII-deficient mouse and anti-factor IXa-treated human blood

Blood flow properties play important roles in the regulation and formation of thrombus. To evaluate the influence of blood flow on thrombus formation in haemophilia, whole blood samples were obtained from FVIII-deficient (FVIII(-/-) ) and wild-type (FVIII(+/+) ) mice (n = 6 respectively), and from six human volunteers. Anti-FIXa aptamer was added to human blood to model acquired haemophilia B. Recalcified whole blood samples containing corn trypsin inhibitor and danaproid were perfused over the microchip coated with collagen and tissue thromboplastin at shear rates of 1100 and 110 s(-1) . Thrombus formation in the capillary was quantified by monitoring flow pressure changes. The intervals to 5 kPa (T(5) ) and 40 k Pa (T(40) ) reflect the onset and growth of thrombus formation respectively. Furthermore, fibrin and platelets in thrombi were quantified by immunostaining. T(5) at both shear rates were similar in FVIII(-/-) and FVIII(+/+) mice. T(40) of FVIII(-/-) mice (1569 ± 565 s) was significantly delayed compared with FVIII(+/+) mice (339 ± 78 s) at 110 s(-1) (P < 0.05), but not at 1100 s(-1) . The delay was normalized by adding human FVIII (2 IU mL(-1) ). Similarly, adding anti-FIXa aptamer to human blood prolonged T(40) at 110 s(-1) (P < 0.01), but not at 1100 s(-1) . Impaired production of fibrin due to anti-FIXa aptamer at 110 s(-1) was shown in the immunostained thrombus. Our perfusion experiments demonstrated that shear rates influence thrombus formation patterns in haemophilia, and that reduced activity of intrinsic tenase (FIXa-FVIIIa) becomes evident under venous shear rates.

A novel automated microchip flow-chamber system to quantitatively evaluate thrombus formation and antithrombotic agents under blood flow conditions

BACKGROUND AND AIMS

In the present study, we describe a newly developed microchip-based analytical system to evaluate white thrombus formation (WTF). Efficacies of various antithrombotic agents were compared under different flow conditions.

METHODS

Whole blood containing corn trypsin inhibitor was perfused over a microchip coated with collagen and tissue thromboplastin at the lower and higher shear rates of 240 and 600 s(-1) , and WTF process inside the microchip was quantified by monitoring a flow pressure. Parameters of T(10) (time to 10 kPa), T(10-80) (time from 10 to 80 kPa) and OT (occlusion time; time to 80 kPa) were used to evaluate the onset and the growth rate of WTF, and the capillary occlusion, respectively.

RESULTS

After perfusion was started, white thrombus composed of activated platelets and fibrin was formed on the coated surface. Thrombus gradually increased in size and eventually occluded the capillary. Among anticoagulants, heparin (0.5-1.0 U mL(-1)) potently prolonged T(10) at both shear rates, whereas low molecular weight heparin (1.0-2.0 IU mL(-1)) inhibited the growth of WTF at the lower shear rate. Among antiplatelet agents, abciximab (1-2 μg mL(-1)) significantly reduced the size and number of thrombi, which was additively enhanced in the presence of heparin (0.5 U mL(-1) ). OS-1 (specific GPIbα-antagonist) prevented the complete capillary occlusion.

CONCLUSION

The novel monitoring system of WTF may be useful in preclinical and clinical evaluations of different types of antithrombotic strategies, and their effects in combination.

Successful treatment of Trichosporon fungemia in a patient with refractory acute myeloid leukemia using voriconazole combined with liposomal amphotericin B

Trichosporon fungemia is a rare and fatal fungal infection that occurs in patients with prolonged neutropenia associated with hematologic malignancies. A 21-year-old male developed Trichosporon fungemia during remission induction therapy for acute myeloid leukemia (AML). Although two courses of induction therapy failed to induce a remission of AML, combination therapy with voriconazole and liposomal amphotericin B (L-AmB) followed by monocyte colony-stimulating factor ameliorated the Trichosporon fungemia and enabled the patient to receive reduced-intensity bone marrow transplantation (BMT) from his human leukocyte antigen-A one-locus mismatched mother. The patient achieved a durable remission after BMT without exacerbation of Trichosporon fungemia. The combination therapy with voriconazole and L-AmB may therefore be useful in controlling Trichosporon fungemia associated with prolonged neutropenia after remission induction therapy for AML.

Transillumination by light-emitting diode facilitates peripheral venous cannulations in infants and small children

BACKGROUND

Transillumination facilitates the visualization of peripheral veins in infants and children. The clinical usefulness of light-emitting diode (LED)-powered devices has not been thoroughly studied.

METHODS

We randomly assigned 136 infants and children weighing <15 kg, undergoing general anesthesia, to red LED-powered transillumination (TM group, n=67) vs. the usual method (UM group, n=69) of peripheral venous cannulations. Venous puncture was performed following anesthesia induction with sevoflurane and nitrous oxide. The primary and secondary study endpoints were the rate of successful cannulations at initial attempt, and the duration of insertion attempts, respectively.

RESULTS

The median score of the estimated cannulation difficulty before attempted puncture was similar in both groups. The success rates at first attempt were 75% and 61% (NS) and mean+/-SD times to successful venous access were 47+/-34 and 68+/-66 s (NS) in the TM and UM groups, respectively. The cannulation procedures were completed significantly earlier in the TM group than in the UM group (hazard ratio, 1.59; 95% confidence interval, 1.03-2.47; P=0.03). In the subgroup of infants and children <2 years old, venous cannulation was successful at first attempt in 73% and 49% in the TM group (n=44) and in the UM group (n=47), respectively (P=0.03).

CONCLUSIONS

LED-powered transillumination devices facilitated peripheral venous cannulations in small infants and children.

Incidence of Carboplatin-related hypersensitivity reactions in Japanese patients with gynecologic malignancies

Carboplatin is one of the most commonly used and well-tolerated agents for gynecologic malignancies. The rate of hypersensitivity reactions (HSRs) in the overall population of patients receiving carboplatin has been reported to increase after multiple doses of the agent. We retrospectively analyzed the incidence, clinical features, management, or outcome of carboplatin-related HSRs in 113 Japanese patients with gynecologic malignancies and the possibility of rechallenge with the drug. We intravenously administered carboplatin after paclitaxel or docetaxel. Mild HSRs are resolved by temporary interruption of carboplatin infusion, an additional antihistamine, and/or a corticosteroid. If HSRs arose, carboplatin was diluted, not exceeding 1 mg/mL, and slowly infused over 2 hours in subsequent cycles. Ten patients experienced carboplatin HSRs, with an overall incidence of 8.85%. The first HSR episode was mild in all cases. When retreated with carboplatin, 4 exhibited severe HSRs. More than 9 cycles and/or more than 5000 mg of carboplatin administration significantly increased the incidence of HSRs. In particular, carboplatin treatment beyond 15 cycles and/or 8000 mg increased the risk of severe HSRs (P < 0.0001). The incidence of HSRs in the ovarian carcinoma group was significantly greater than that in the uterine carcinoma group (P = 0.0046). Careful attention should be paid to HSRs during carboplatin treatment beyond 9 cycles and/or 5000 mg. The rate of severe HSRs greatly increases beyond 15 cycles and/or 8000 mg. Further studies are needed to identify potential risk factors that may contribute to the development of carboplatin HSRs and to decrease the risk of reactions.

Equivocal colonic carcinogenicity of Aloe arborescens Miller var. natalensis berger at high-dose level in a Wistar Hannover rat 2-y study

A 2-y carcinogenicity study of Aloe, Aloe arborescens Miller var. natalensis Berger, a food additive, was conducted for assessment of toxicity and carcinogenic potential in the diet at doses of 4% or 0.8% in groups of male and female Wistar Hannover rats. Both sexes receiving 4% showed diarrhea, with loss of body weight gain. The survival rate in the 4% female group was significantly increased compared with control females after 2 y. Hematological and biochemical examination showed increase of RBC, Hb, and Alb in the 4% males. The cause of these increases could conceivably have been dehydration through diarrhea. AST and Na were significantly decreased in the males receiving 4%, and Cl was significantly decreased in both 4% and 0.8% males. A/G was significantly increased in the 4% females, and Cl was significantly decreased (0.8%) in the female group. Histopathologically, both sexes receiving 4% showed severe sinus dilatation of ileocecal lymph nodes, and yellowish pigmentation of ileocecal lymph nodes and renal tubules. Adenomas or adenocarcinomas in the cecum, colon, and rectum were observed in 4% males but not in the 0.8% and control male groups. Similarly, in females, adenomas in the colon were also observed in the 4% but not 0.8% and control groups. In conclusion, Aloe, used as a food additive, exerted equivocal carcinogenic potential at 4% high-dose level on colon in the 2-y carcinogenicity study in rats. Aloe is not carcinogenic at nontoxic-dose levels and that carcinogenic potential in at 4% high-dose level on colon is probably due to irritation of the intestinal tract by diarrhea.