Global Medical Device Clinical Trials Involving Both the United States and Japan: Key Considerations for Development, Regulatory Approval, and Conduct.

As medical device development becomes increasingly global, the opportunities and potential advantages offered by international clinical trial and regulatory approval strategies are also growing. In particular, medical device clinical trials involving sites in both the United States and Japan and intended to support marketing in both countries may warrant particular consideration, given the similarities in their regulatory systems, patients and clinical practice patterns, and market sizes. Since 2003, the US-Japan Harmonization By Doing (HBD) initiative has been focused on identifying and addressing clinical and regulatory barriers to medical devices access in both countries via collaboration between governmental, academic, and industry stakeholders. Through the efforts of HBD participants, US-Japanese clinical trials have been conducted and the resulting data have supported regulatory approval for marketing in both countries. Based on these experiences, this paper outlines some of the key factors to consider when developing a global clinical trial involving US and Japanese participation. These considerations include the mechanisms for consultation with regulatory authorities on clinical trial strategies, the regulatory framework for clinical trial notification and approval, recruitment and conduct of clinical sites, and lessons learned from specific US-Japanese clinical trial experiences. The goal of this paper is to promote global access to promising medical technologies by assisting potential clinical trial sponsors in understanding when an international strategy may be appropriate and successful.

Japan-USA Orbital Atherectomy for Calcific Coronary Lesions: COAST Study, a Harmonization by Doing Proof-of-Concept: The Japanese and US Regulatory Perspective.

Regulatory approval processes for medical devices in Japan and the United States of America (US) often require similar clinical trials to establish safety and effectiveness. The Harmonization by Doing (HBD) program provides a collaborative environment for communication between regulators, academics and industry, facilitating the design and conduct of US/Japanese clinical trials supporting approval in both countries.

Quantification of a cell-mediated immune response against varicella zoster virus by assessing responder CD4high memory cell proliferation in activated whole blood cultures.

BACKGROUND: Herpes zoster (HZ) is caused by reactivation of a latent varicella zoster virus (VZV). The potential to develop HZ increases with age due to waning of memory cell-mediated immunity (CMI), mainly the CD4 response. Therefore, VZV-CD4-memory T cells (CD4-M) count in blood could serve as a barometer for HZ protection. However, direct quantification of these cells is known to be difficult because they are few in number in the blood. We thus developed a method to measure the proliferation level of CD4-M cells responding to VZV antigen in whole blood culture. METHODS: Blood samples were collected from 32 children (2-15 years old) with or without a history of varicella infection, 18 young adults (28-45 years old), and 80 elderly (50-86 years old) with a history of varicella infection. The elderly group was vaccinated, and blood samples were taken 2 months and 1 year after VZV vaccination. Then, 1 mL of blood was mixed with VZV, diluted 1/10 in medium, and cultured. CD4-M cells were identified and measured by flow cytometry. RESULTS: There was distinct proliferation of CD3+CD4highCD45RA-RO+ (CD4high-M) cells specific to VZV antigen at day 9. The majority of CD4high-M cells had the effector memory phenotype CCR7- and was granzyme B-positive. CD4high-M cells were detected in blood culture from varicella-immune but not varicella-non-immune children. Meanwhile, a higher level of CD4high-M proliferation was observed in young adults than in the elderly. The CD4high-M proliferation level was boosted 2 months after VZV vaccination and maintained for at least 1 year in the elderly. CONCLUSION: Quantifying VZV responder CD4high -M cell proliferation is a convenient way to measure VZV CMI using small blood volumes. Our method can be applied to measure VZV vaccine-induced CMI in the elderly. Clinical study registry numbers: (www.clinicaltrials.jp) 173532 and 183985.

Design Strategies for Global Clinical Trials of Endovascular Devices for Critical Limb Ischemia (CLI)　- A Joint USA-Japanese Perspective.

For more than 10 years, the Harmonization by Doing (HBD) program, a joint effort by members from academia, industry and regulators from the United States of America (USA) and Japan, has been working to increase timely regulatory approval for cardiovascular devices through the development of practical global clinical trial paradigms. Consistent with this mission and in recognition of the increasing global public health effects of critical limb ischemia (CLI), academic and government experts from the USA and Japan have developed a basic framework of global clinical trials for endovascular devices for CLI. Despite differences in medical and regulatory environments and complex patient populations in both countries, we developed a pathway for the effective design and conduct of global CLI device studies by utilizing common study design elements such as patients' characteristics and study endpoints, and minimizing the effect of important clinical differences. Some of the key recommendations for conducting global CLI device studies are: including patients on dialysis; using a composite primary endpoint for effectiveness that includes 6-month post-procedure therapeutic success and target vessel patency; and using a 30-day primary safety endpoint of perioperative death and major adverse limb events. The proposed approach will be uniquely beneficial in facilitating both the initiation and interpretation of CLI studies and accelerating worldwide CLI device development and innovation.

Bioengineered silkworms with butterfly cytotoxin-modified silk glands produce sericin cocoons with a utility for a new biomaterial.

Genetically manipulated organisms with dysfunction of specific tissues are crucial for the study of various biological applications and mechanisms. However, the bioengineering of model organisms with tissue-specific dysfunction has not progressed because the challenges of expression of proteins, such as cytotoxins, in living cells of individual organisms need to be overcome first. Here, we report the establishment of a transgenic silkworm (Bombyx mori) with posterior silk glands (PSGs) that was designed to express the cabbage butterfly (Pieris rapae) cytotoxin pierisin-1A (P1A). P1A, a homolog of the apoptosis inducer pierisin-1, had relatively lower DNA ADP ribosyltransferase activity than pierisin-1; it also induced the repression of certain protein synthesis when expressed in B. mori-derived cultured cells. The transgene-derived P1A domain harboring enzymatic activity was successfully expressed in the transgenic silkworm PSGs. The glands showed no apoptosis-related morphological changes; however, an abnormal appearance was evident. The introduced truncated P1A resulted in the dysfunction of PSGs in that they failed to produce the silk protein fibroin. Cocoons generated by the silkworms solely consisted of the glue-like glycoprotein sericin, from which soluble sericin could be prepared to form hydrogels. Embryonic stem cells could be maintained on the hydrogels in an undifferentiated state and proliferated through stimulation by the cytokines introduced into the hydrogels. Thus, bioengineering with targeted P1A expression successfully produced silkworms with a biologically useful trait that has significant application potential.

Lectin-like oxidized LDL receptor 1 is involved in CRP-mediated complement activation.

BACKGROUND: C-reactive protein (CRP) is purported to be a risk factor that acts independently of LDL cholesterol in predicting all-cause mortality in patients with ischemic heart disease. Lectin-like oxidized LDL receptor 1 (LOX-1) impairs endothelial function and exacerbates myocardial injury. We recently demonstrated that CRP increased vascular permeability through direct binding to LOX-1. Here we examined, using a hypertensive rat model, whether LOX-1 is involved in CRP-induced complement activation. METHODS AND RESULTS: In the cultured LOX-1-expressing cell line hLOX-1-CHO, CRP increased complement activation, but did not do so in native CHO cells. Depleting C1q from serum abolished CRP-induced complement activation. Incubation of CRP with serum on immobilized recombinant LOX-1 similarly showed that CRP activated C1q-requiring classical complement pathway in a LOX-1-dependent manner. Interestingly, the interaction between CRP and LOX-1 was dependent on Ca²âº ion and competed with phosphocholine, suggesting that LOX-1 bound to the B-face of CRP with a phosphocholine-binding domain. This was in contrast to Fcγ receptors, to which CRP bound in A-face with complement-binding domain. In vivo, intradermal injection of CRP to hypertensive SHRSP rats induced complement activation detected by C3d deposition and leukocyte infiltration around the injected area. Anti-LOX-1 antibody reduced the extent of complement activation and leukocyte infiltration. CONCLUSIONS: LOX-1 appears to be involved in CRP-induced complement activation, and thus may serve to locate the site of CRP-induced complement activation and inflammation.

The discovery of LOX-1, its ligands and clinical significance.

LOX-1 is an endothelial receptor for oxidized low-density lipoprotein (oxLDL), a key molecule in the pathogenesis of atherosclerosis.The basal expression of LOX-1 is low but highly induced under the influence of proinflammatory and prooxidative stimuli in vascular endothelial cells, smooth muscle cells, macrophages, platelets and cardiomyocytes. Multiple lines of in vitro and in vivo studies have provided compelling evidence that LOX-1 promotes endothelial dysfunction and atherogenesis induced by oxLDL. The roles of LOX-1 in the development of atherosclerosis, however, are not simple as it had been considered. Evidence has been accumulating that LOX-1 recognizes not only oxLDL but other atherogenic lipoproteins, platelets, leukocytes and CRP. As results, LOX-1 not only mediates endothelial dysfunction but contributes to atherosclerotic plaque formation, thrombogenesis, leukocyte infiltration and myocardial infarction, which determine mortality and morbidity from atherosclerosis. Moreover, our recent epidemiological study has highlighted the involvement of LOX-1 in human cardiovascular diseases. Further understandings of LOX-1 and its ligands as well as its versatile functions will direct us to ways to find novel diagnostic and therapeutic approaches to cardiovascular disease.

An alternative protein standard to measure activity of LOX-1 ligand containing apoB (LAB) - utilization of anti-LOX-1 single- chain antibody fused to apoB fragment.

AIM: We have recently demonstrated that the circulating level of LOX-1 ligand containing apoB (LAB) predicts the risk of cardiovascular events; however, as is the case in other assays measuring oxidized LDL (oxLDL), chemical unstability and inter-lot variance of standard oxLDL may limit the utility of measuring LAB. This study aimed to develop an alternative protein standard that is simultaneously recognized by LOX-1 and anti-apoB antibody instead of copper-oxidized LDL. METHODS AND RESULTS: cDNAs encoding the variable regions of anti-LOX-1 monoclonal antibody were cloned from hybridomas and reorganized to express anti-LOX-1 single-chain variable fragment (Fv). cDNAs of four regions of human apoB (B1 to B4), which were reported to be epitopes of many anti-apoB antibodies, were also cloned. After confirming the respective reactivity of Fv and apoB fragments to LOX-1 and anti-apoB antibodies, cDNAs of Fv and apoB fragments were connected to express Fv-ApoB chimeric proteins. These fusion proteins were found to be recognized by both LOX-1 and anti-apoB antibodies. Among them, the fusion proteins of Fv-B1 and Fv-B3 gave saturable binding curves against immobilized LOX-1 when detected by anti-apoB antibodies. The binding curves of different Fv-B1 preparations to LOX-1 were almost identical while those of oxLDL varied among the preparations, suggesting better quality control of Fv-B1 preparations. CONCLUSIONS: The fusion proteins composed of Fv-form anti-LOX-1 antibody and apoB fragment are useful alternatives to copper-oxidized LDL in determining LAB, which would facilitate the application of modified LDL analyses to the clinical diagnosis and risk evaluation of cardiovascular disease.

LOX index, a novel predictive biochemical marker for coronary heart disease and stroke.

BACKGROUND: Lectin-like oxidized LDL receptor 1 (LOX-1) is implicated in atherothrombotic diseases. Activation of LOX-1 in humans can be evaluated by use of the LOX index, obtained by multiplying the circulating concentration of LOX-1 ligands containing apolipoprotein B (LAB) times that of the soluble form of LOX-1 (sLOX-1) [LOX index = LAB x sLOX-1]. This study aimed to establish the prognostic value of the LOX index for coronary heart disease (CHD) and stroke in a community-based cohort. METHODS: An 11-year cohort study of 2437 residents age 30-79 years was performed in an urban area located in Japan. Of these, we included in the analysis 1094 men and 1201 women without history of stroke and CHD. We measured LAB and sLOX-1 using ELISAs with recombinant LOX-1 and monoclonal anti-apolipoprotein B antibody and with 2 monoclonal antibodies against LOX-1, respectively. RESULTS: During the follow-up period, there were 68 incident cases of CHD and 91 cases of stroke (with 60 ischemic strokes). Compared with the bottom quartile, the hazard ratio (HR) of the top quartile of LOX index was 1.74 (95% CI 0.92-3.30) for stroke and 2.09 (1.00-4.35) for CHD after adjusting for sex, age, body mass index, drinking, smoking, hypertension, diabetes, non-HDL cholesterol, and use of lipid-lowering agents. Compared with the bottom quartile of LOX index, the fully adjusted HRs for ischemic stroke were consistently high from the second to the top quartile: 3.39 (95% CI 1.34-8.53), 3.15 (1.22-8.13) and 3.23 (1.24-8.37), respectively. CONCLUSIONS: Higher LOX index values were associated with an increased risk of CHD. Low LOX index values may be protective against ischemic stroke.

Lox-1: the multifunctional receptor underlying cardiovascular dysfunction.

Oxidatively modified low-density lipoprotein (oxLDL) is implicated in the pathogenesis of atherosclerosis. Endothelial dysfunction is the initial change in the vascular wall that induces morphological changes for atheroma-formation. Lectin-like oxidized LDL receptor-1 (LOX-1) was identified as the receptor for oxLDL that was thought to be a major cause of endothelial dysfunction. LOX-1 has been demonstrated to contribute not only to endothelial dysfunction, but also to atherosclerotic-plaque formation, myocardial infarction and intimal thickening after balloon injury. Recent findings on the genetics of LOX-1 and the methodology to detect it and its ligands would further facilitate the examination of the receptor's pathophysiological contribution in atherosclerosis. Furthermore, LOX-1-related tools might open new gateways from diagnosis to therapeutics for cardiovascular diseases.

Generation and characterization of chicken monoclonal antibodies against human LOX-1.

Lectin-like oxidized low-density lipoprotein (LDL) receptor-1 (LOX-1) is the major receptor for oxidized LDL (oxLDL), and plays a key role in the pathogenesis of atherosclerosis and cardiovascular diseases. Monoclonal antibodies (mAbs) specific for human LOX-1 (hLOX-1) were generated by a phage display technique using chickens immunized with recombinant hLOX-1 (rhLOX-1). A total of 53 independent scFv clones reactive for rhLOX-1 were obtained. Of the 53 clones, 49 recognized the C-type lectin-like domain (CTL domain), which contributes to the binding of oxLDL. Of these, 45 clones inhibited oxLDL-binding with LOX-1. Furthermore, some of these clones cross-reacted with rabbit, pig and/or mouse LOX-1. For possible application as therapeutic agents in the future, two cross-reactive mAbs were re-constructed as chicken-human chimeric antibodies. The chimeric antibodies showed similar characteristics compared to the original antibodies, and inhibited oxLDL binding to LOX-1 expressed on CHO cells. The results obtained in this study indicate that anti-LOX-1 mAbs might be useful tools for functional analyses and development of therapeutic agents for cardiovascular indications such as atherosclerosis.

Pontine infarction induced by injury of the perforating branch of the basilar artery after blunt head impact: case report.

A 77-year-old male pedestrian was hit by a car. On admission, he had disturbance of consciousness and left hemiplegia. Computed tomography (CT) indicated only left frontal subcutaneous hematoma and minor hemorrhage in the left frontal lobe, suggesting axonal injury. CT on hospital day 2 revealed a low density area in the right paramedian pons, but CT angiography showed no dissection or occlusion of the vertebrobasilar artery. The diagnosis was pontine infarction resulting from shearing force injury to the paramedian branch of the basilar artery. He was transferred to another hospital for rehabilitation without improvement of symptoms on hospital day 51. Paramedian pontine infarction tends to occur in patients with risk factors for arteriosclerosis, including hypertension, diabetes mellitus, hyperlipidemia, or smoking. The present elderly patient had hypertension and hyperlipidemia, so arteriosclerosis in the paramedian branch may have contributed to his susceptibility to such injury.

Evaluation of the accuracy of CT numbers in statistical correction of nonlinearity for polychromatic X-ray CT projection data.

The CT number is theoretically independent of the number of incident photons and the thickness of a subject. However, when noise is added, the CT number becomes dependent on the number of incident photons because of the nonlinearity of the logarithm operation, and so the accuracy of the CT number is degraded, especially in a photon-starved state. The inconsistency of the CT number due to nonlinearity generates an intense streak artifact in a reconstructed image. We have theoretically clarified the statistical characteristics of both the nonlinearity of the logarithm transform and the non-zero/non-negative restriction in the logarithm operation. Moreover, we have formulated a correction method for such nonlinearity according to the statistical distribution of noise, and we carried out computer simulations for monochromatic X-ray beams. However, the applicability to polychromatic-energy photons has not been confirmed. The artifacts induced by the beam-hardening effect, which occurs when incident beams are polychromatic, remarkably deteriorate the accuracy of the CT number. In this paper, we quantitatively evaluate the improvement of the quality of reconstructed images by our correction method by using a numerical experiment when incident beams are polychromatic. The experimental results show that there is less influence on spatial resolution and that the CT number is hardly dependent on the number of incident photons for a polychromatic beam as well as a monochromatic beam. Moreover, the results suggest the possibility that the same image quality is obtained at a much lower exposure level than the clinical exposure level of low-dose CT.

YCM1008A, a novel Ca2+-signaling inhibitor, produced by Fusarium sp. YCM1008.

In the course of screening for drugs that suppress the Ca(2+)-mediated growth inhibition in a yeast mutant, we found that the metabolite of Fusarium sp. strain YCM1008 inhibited Ca(2+)-signaling. A novel pyrano-pyridone, YCM1008A was isolated from the fermentation broth using HLB column chromatography followed by HPLC, and the structure was elucidated by spectral analysis. YCM1008A suppressed Ca(2+)-induced growth inhibition of the Saccharomyces cerevisiae (Deltazds1Deltasyr1) mutant.

Increased platelet aggregation and production of platelet-derived microparticles after surgery for upper gastrointestinal malignancy.

BACKGROUND: Since platelet function is known to play a major role in arterial thrombosis, we investigated postsurgery alterations in platelet function that might predispose patients with upper gastrointestinal malignancy to postoperative thrombotic complications. SUBJECTS AND METHODS: Shear-induced platelet aggregation (SIPA) in platelet-rich plasma was measured in 23 patients who elected to undergo abdominal surgery. Measurement was done by cone-plate viscometer under low shear stress (12 dyn/cm(2)), a physiological condition, and under high shear stress (108 dyn/cm(2)), a pathological condition that simulates in vivo conditions such as those in stenotic arteries. Platelet microparticle (PMP) formation was analyzed by flow cytometry. Plasma von Willebrand factor (vWF) was also measured. RESULTS: SIPA under high shear stress was significantly enhanced from 44.0 +/- 13.4% preoperatively to 69.5 +/- 15.8% on postoperative day (POD) 1, and it returned to preoperative levels on POD 14. PMP formation under high shear stress was enhanced before surgery (140.8 +/- 38.7%) compared to that under a static condition, and the enhancement was further augmented on POD 1 (219.1 +/- 49.3%). The enhancement of SIPA and PMP formation had no association with disease stage. vWF levels increased significantly on POD 1. Exogenous vWF augmented SIPA and PMP formation under high shear stress, and this augmentation was inhibited by anti-vWF antibody. CONCLUSIONS: Because PMPs are highly procoagulant, increased SIPA and PMP formation induced by surgical intervention possibly contribute to thrombotic complications. Blockage of platelet interaction with vWF may prevent arterial thrombus formation perioperatively.

Treatment of varicose veins: an assessment of intraoperative and postoperative compression sclerotherapy.

Since thrombotic complications, such as superficial thrombophlebitis and subsequent skin pigmentation, are common after sclerotherapy, we conducted a study to evaluate whether combining sclerotherapy with ligation of varicose veins minimizes complications and what timing for sclerotherapy would be most beneficial-accompanying surgery or several weeks postsurgery. Surgical intervention and compression sclerotherapy were performed consecutively on 111 limbs (group A), and sclerotherapy was performed 28 days after surgical intervention on 87 limbs (group B). The volume of sclerosant used and the frequency of complications (thrombus formation and pigmentation) were analyzed. Plasma levels of thrombin-antithrombin III complex (TAT) and D-dimer (DD), as markers for activation of coagulation, were compared. In group A, the total volume of sclerosant used in patients with complications was significantly higher than that in patients without complications. The frequency of thrombus formation and of pigmentation was significantly lower (p <0.01) in group B (10% and 18%, respectively) than in group A (21% and 37%, respectively). The plasma levels of TAT 7 days after treatment were significantly lower in group B (3.4 +/- 1.2 mg/L) than in group A (4.9 +/- 1.1 mg/L). Performing compression sclerotherapy 28 days after surgical intervention is effective for reducing complications and a good alternative for patients with an underlying hypercoagulable state.