To obtain better insight into the pathogenesis of verotoxin-producing Escherichia coli-associated diseases, in this study, we explored the effect of verotoxin 2 (VT2) on coagulation in an animal model. After being given VT2 (50 ng/kg, lethal dose), C57BL/6 mice showed progressively increasing expression of TF mRNA in the kidney and brain and elevated plasma levels of thrombin-antithrombin III complex (TAT), normotest, fibrinogen, and PAI-1 paralleling the disease course over 24 hours; platelet counts were decreased at 48 hours with hemorrhage in the kidney and brain. Co-administration of lipopolysaccharide (LPS, 0.5 mg/kg) with VT2 (50 ng/kg) exhibited more prominant and/or prolonged increase in not only expression of TF and PAI-1 mRNAs in the kidney and brain but also plasma levels of TAT, fibrinogen, and PAI-1 and was associated with more remarkable hemorrhage in the tissues. Although VT2 (5 ng/kg) was not a lethal dose, co-administration of LPS (0.5 mg/kg) with VT2 (5 ng/kg) enhanced the susceptibility to VT2, resulting in more prolonged elevation of TAT levels during the first 24 hours than that in the LPS group and a second elevation at 72 hours, followed by death. Plasma IL-1beta level reached a maximum at 24 hours after VT2 (50 ng/kg) injection prior to the increase in TAT levels, whereas the increase in TNFalpha level immediately after injection was associated with the increase in PAI-1 mRNA. These observations indicate that the activation of coagulation by VT2 may occur through a mechanism different from that used by LPS, since plasma TAT levels rose in the mice immediately after LPS injection and returned to normal over 36 hours.

Animals↗

PubMed2000

Tissue characterization of atherosclerotic plaques by intravascular ultrasound radiofrequency signal analysis: an in vitro study of human coronary arteries.

BACKGROUND: Conventional gray-scale images of intravascular ultrasound (IVUS) cannot accurately differentiate histologic subtypes of sonolucent coronary plaques with or without a lipid core. METHODS: We analyzed radiofrequency signals obtained in vitro from 24 regions of interest (ROI) of noncalcified (sonolucent) plaques in 10 atherosclerotic coronary artery specimens pressure-fixed by formalin. Radiofrequency signals were sampled with a 30-MHz IVUS catheter and digitized at 500 MHz in 8-bit resolution. The ROIs were histologically categorized into 12 plaques with a lipid core and 12 plaques without it. Integrated backscatter and statistical parameters of the radiofrequency envelope (mean/SD ratio [MSR], skewness, and kurtosis) within the ROI were calculated offline, and their ability to detect a lipid core was compared with visual analysis of the IVUS video images. In the group with lipid cores, percent area of a lipid core in each ROI was measured in a digitized histologic image by a computerized planimeter. RESULTS: Sensitivity and specificity of MSR, skewness, and kurtosis for lipid core detection were substantially greater than visual video image analysis (83.3% and 91.7%, 100% and 91.7%, 100% and 91.7% vs 53.3% and 71.7%). Furthermore, the parameters of integrated backscatter, MSR, skewness, and kurtosis were significantly correlated to percent of core area (r = -0.64, -0.73, 0.78, and 0.63, respectively; P<.05). CONCLUSIONS: Compared with IVUS video images, the parameters of radiofrequency signal analysis may be used to aid in more accurate detection and quantitative evaluation of a lipid core, which is one of the major factors of a vulnerable coronary plaque.

Coronary Artery Disease↗

PubMed2000

Cost analysis between stent and conventional balloon angioplasty.

The present study evaluated the cost of coronary stenting compared with conventional balloon angioplasty in Japan. Procedural cost was estimated as the sum of the procedural fee and the cost of devices such as angioplasty balloon and stent. The data such as the number of balloon catheters and stents used, and the rate of crossovers that was shown by the Stent Restenosis Study (STRESS) were applied to calculate the costs of stenting and conventional balloon angioplasty. For the estimation of hospital room and nursing costs, the length of the in-hospital stay was estimated at 7 days. The costs of procedures such as laboratory and radiological tests were determined based on routine coronary intervention at Chiba University Hospital. The rates of target lesion revascularization in the STRESS trial (conventional balloon angioplasty: 21%, stenting: 15%) were used to calculate the cost during follow up. The in-hospital costs of conventional balloon angioplasty and stenting were estimated to be Yens 982,300 and Yens 1,416,893, respectively. The overall costs, including follow-up cost, of conventional balloon angioplasty and stenting were estimated to be Yens 1,188,583 and Yens 1,564,238, respectively. The in-hospital cost of stenting is higher compared with conventional balloon angioplasty because of greater balloon use and direct stent cost. Lower target lesion revascularization reduces the cost difference between conventional balloon angioplasty and stenting, but the higher initial cost of stenting is not fully offset.

Angioplasty, Balloon↗

PubMed2000

Descending aorta wall volume and coronary artery disease: a comparative study using enhanced computed tomography of the chest and coronary angiography.

The study examined the association between aortic wall volume (AWV) detected by enhanced computed tomography and coronary artery atherosclerosis observed on angiography. In 180 cases, AWV was measured as the total wall volume of a 7-cm portion of the descending thoracic aorta distal from the tracheal bifurcation. Coronary artery atherosclerosis was angiographically quantified by both Gensini score, in terms of the severity of coronary artery stenosis, and Extent score, in terms of the severity of coronary artery involvement. Mean AWV values between the patients with significant coronary artery stenosis and those without significant stenosis were 9.83+/-4.04 cm3 and 8.09+/-2.39 cm3, respectively (p<0.001). AWV was a significantly independent variable for significant coronary artery disease (p=0.0097) and an Extent score > or = 60 (p=0.0092). Calcification of AWV, however, was not associated with coronary atherosclerosis. The quantification of aortic atherosclerosis was useful for diagnosing coronary artery disease.

Aged↗

PubMed2000

Limited balloon expansion through the struts of the Palmaz-Schatz and NIR stents compared with the Multi-Link stent.

After placing a stent in the main vessel of a bifurcation lesion, it is sometimes necessary to perform further balloon inflation in order to treat an ostial lesion in a side branch. The stent struts may prevent full balloon expansion at the ostium of a side branch, resulting in residual ostial stenosis. The degree of completeness of balloon inflation may vary significantly depending on the stent design and structure. A model of a bifurcation lesion with an angle of 45 degrees was created from acrylic resin. The diameters of the main vessel and the side branch were both 3.5 mm. Deployment of the Palmaz-Schatz stent (n=5), NIR stent (n=5) or Multi-Link stent (n=5) was performed in the main vessel with a 3.5-mm balloon catheter inflated to 12 atm. A 3.5-mm balloon catheter was then inflated to 12 atm through the stent struts of the main vessel and into the ostium of the side branch. The degree of completeness of balloon inflation (% balloon expansion) was calculated as (smallest diameter of balloon catheter/reference diameter of balloon catheter) x 100%. The minimal lumen diameter (MLD) and cross-sectional area (CSA) at the ostium of the side branch created with the stent struts were also measured. Limited balloon expansion through the struts was observed with the Palmaz-Schatz stent and the NIR stent, but almost full balloon expansion was observed with the Multi-Link stent (% balloon expansion: Palmaz-Schatz stent 80%, NIR stent 60%, Multi-Link stent 94%, p<0.01). The MLD and CSA of the dilated struts, representing the ostium of the side branch, of the Palmaz-Schatz stent (2.2+/-0.1 mm, 4.5+/-0.3 mm2) and the NIR stent (1.8+/-0.1 mm, 3.1+/-0.3 mm2) were significantly smaller compared with those of the Multi-Link stent (3.0+/-0.2 mm, 8.4+/-0.6 mm2) (p<0.01). The struts of the Palmaz-Schatz stent and the NIR stent deployed in the main vessel of a bifurcation prevent full expansion of a balloon catheter inflated at the side branch ostium. In contrast, almost full balloon expansion through the struts of the Multi-Link stent is achieved.

Catheterization↗

PubMed1999

Feasibility of in vivo intravascular ultrasound tissue characterization in the detection of early vascular transplant rejection.

BACKGROUND: Unprocessed ultrasound radiofrequency (RF) signal analysis has been shown to distinguish different tissue structures more reliably than gray-scale interpretation of conventional ultrasound images. METHODS AND RESULTS: The objective of this study was to test the feasibility of in vivo intravascular ultrasound (IVUS) RF signal analysis in an animal model of allograft rejection. Six cynomolgus monkeys underwent transplantation of 3-cm aortic allograft segments distal to the renal arteries from immunologically mismatched donors. IVUS imaging with a 30-MHz system was performed 84 to 105 days after the operation. RF signals were acquired from cross sections of the recipient and the allograft aortas in real time with a digitizer at 500 MHz with 8-bit resolution. Sixty-five cross sections and 68 regions of interest (31 in host aorta and 37 in allograft) were analyzed in the adventitial layer with a total number of 8568 vectors processed. For each region of interest, a weighted-average attenuation was calculated on the basis of the attenuation and length for each individual vector. Histological examination was performed at every cross section imaged by IVUS. When the gray-scale images of conventional IVUS scored by an independent observer were compared, no distinction between adventitia of the native aorta and allograft was possible. Analysis of the average RF backscatter power also showed no significant difference (70.32+/-3.55 versus 70.72+/-3.38 dB). However, the average attenuation of allografts was significantly lower than that of the host aortas (2.64+/-1.38 versus 4.02+/-1.16 dB/mm, P<0.001). Histology demonstrated a marked adventitial inflammatory response in all allografts, with no inflammation observed in the host aortas. CONCLUSIONS: In vivo IVUS tissue characterization can be performed during routine imaging. In this model of transplant vasculopathy, RF attenuation measurements were more sensitive than visual or quantitative gray-scale analysis.

Animals↗

PubMed1999

Purification, identification, and cDNA cloning of Cha o 2, the second major allergen of Japanese cypress pollen.

The second major allergen of Chamaecyparis obtusa (Japanese cypress) pollen, Cha o 2, has been purified and its cDNA cloned. Of patients with pollinosis caused by C. obtusa, 82.5% produce IgE antibodies which react with purified Cha o 2. The purified protein has a molecular mass of 46 kDa and its 12 N-terminal amino acid sequence displays a high homology with that of Cry j 2, the second major allergen of Cryptomeria japonica pollen. cDNA clones coding for Cha o 2 have been isolated using Cry j 2 cDNA as a probe. Cha o 2 cDNA clones were sequenced and found to code a putative 50-residue signal sequence and a 464-residue mature protein with a molecular weight of 50 kDa. Two possible N-linked glycosylation sites were found in the sequence. The deduced amino acid sequence of Cha o 2 shows 74.3% identity with that of Cry j 2. In its primary structure, Cha o 2 shows significant identity with those of the polygalacturonases of avocado, tomato, and maize as well as Cry j 2.

Allergens↗

PubMed1999

The progression of thrombus in an ex-vivo shunt model evaluated by intravascular ultrasound radiofrequency analysis.

We tested the ability of ultrasound radiofrequency (RF) signal analysis to characterize thrombus accumulation in a Dacron graft incorporated into the exteriorized arteriovenous shunt in 3 baboons with constant blood flow for 60 min. Thrombus formation was quantified by sequential measurements of 111Indium-labeled platelet deposition. RF signals were acquired every 15 min at 2 sites in the graft, using a 2.9 Fr intravascular ultrasound catheter-based transducer (30 MHz) and digitized at 250 MHz in 8-bit resolution. Regions of interest were placed within a 0.5-mm perimeter adjacent to the graft wall. Integrated backscatter increased significantly (p < 0.001) with increasing platelet deposition. However, mean-to-standard deviation ratio of the RF envelope showed no significant change and the distribution pattern of the RF probability function remained constant and consistent with a Rayleigh scattering process. These results provide a basis for using RF analysis to monitor the time-course of thrombus formation.

Analysis of Variance↗

PubMed1999

Peptide specificity, HLA class II restriction, and T-cell subsets of the T-cell clones specific to either Cry j 1 or Cry j 2, the major allergens of Japanese cedar (Cryptomeria japonica) pollen.

BACKGROUND: Cry j 1 and Cry j 2 are thought to be the major allergens of Japanese cedar pollen. HLA class II types capable of presenting T-cell epitopes in both allergens and their role in induction of T-cell subsets are not well known. METHODS: CD4+ T (Th)-cell clones (TCCs) specific to either Cry j 1 or Cry j 2 were generated. HLA class II restrictions were determined by their reactivity to the T-cell epitope in the presence of antigen presenting cells sharing matched types. Interleukin (IL)-2, interferon-gamma, IL-4, and IL-5 contents in the supernatants of TCCs were estimated using enzyme immunoassay. RESULTS: Peripheral blood mononuclear cells (PBMC) from patients induced proliferation with 100 microgram/ml Cry j 1 or 3-10 microgram/ml rCry j 2 stimulation. T-cell epitopes in Cry j 1 were presented to Th cells by the gene products of DRA1*01/DRB1*0901, DRA1*01/DRB5*0101, DQA1* 0102/DQB1*0602, and DPA1*01/DPB1*0501; those in Cry j 2 were restricted by DRA1*01/DRB1*0901, DRA1* 01/DRB1*1501, DRA1*01/DRB4*01, DRA1*01/DRB5* 0101, DQA1*0102/DQB1*0602, DPA1*01/DPB1*0201, and DPA1*01 and *0202/DPB1*0501. Type 2-like cells were preferentially induced in Cry j 1 stimulation, while an almost equal number of type 2- and type 1-like cells was induced in rCry j 2. CONCLUSIONS: No clear correlation existed between peptide specificity, HLA class II restriction and induction of Th-cell subsets, suggesting that the requirement of different dose of Cry j 1 or Cry j 2 to induce proliferation in PBMC may lead to distinguishable difference in induction of Th subsets between TCCs specific to Cry j 1 and Cry j 2.

Adult↗

PubMed1998

T cell epitopes in Japanese cedar (Cryptomeria japonica) pollen allergens: choice of major T cell epitopes in Cry j 1 and Cry j 2 toward design of the peptide-based immunotherapeutics for the management of Japanese cedar pollinosis.

Japanese cedar pollinosis is caused by exposure to Japanese cedar (Cryptomeria japonica) pollen, of which two components, Cry j 1 and Cry j 2, are believed to be the major allergens. T cell lines specific to either Cry j 1 or rCry j 2 were reactive to various portions of each panel of overlapping peptides derived from Cry j 1 or Cry j 2. Two peptides, p211-225 and p108-120, from among six major T cell epitopes identified in Cry j 1 sequence, and three peptides, p182-200, p344-355, and p66-80, from among five in Cry j 2, were chosen to design an artificial polypeptide (named Cry-consensus) based on a difference among the types of the restriction molecules capable of presenting these peptides. After construction of a DNA encoding these peptides in order, Cry-consensus was expressed in Escherichia coli. Five of six T cell epitopes, except for Cry j 2 p344-355, in Cry-consensus were recognized by the T cell clones specific to each peptide. PBMC from allergic patients induced higher proliferation under stimulation from Cry-consensus than individual peptides. Eighty-eight percent of the PBMC (15 of 17) showed proliferation under the Cry-consensus stimulation. Thus, several major T cell epitopes from Cry j 1 and Cry j 2 can be chosen in the design of peptide-based immunotherapeutics for the management of Japanese cedar pollinosis in subjects having various types of HLA class II molecules.

Adult↗

PubMed1998

[Assessment of saphenous vein graft wall characteristics with intravascular ultrasound imaging].

The wall characteristics of saphenous vein grafts (SVGs) after coronary artery bypass grafting (CABG) were assessed with intravascular ultrasound (IVUS) imaging. Twenty-seven SVGs in 25 patients who had undergone CABG were studied with IVUS in vivo. Ten SVGs excised from 6 patients who had undergone reoperation were studied with IVUS in vitro. The results were compared with the histopathologic findings. IVUS images of four SVGs studied within 1 month after CABG showed a thin and single-layer structure, which was almost identical to the IVUS features of a normal, fresh SVG. In five SVGs studied between 3 months and 1 year after CABG, the wall thickness was increased, and there were hypoechoic areas. In sixteen SVGs studied more than 2 years after CABG, two patterns were noted on IVUS imaging. One pattern was a triple-layer structure of alternating hyperechoic, hypoechoic, and hyperechoic bands seen in the angiographically normal sections of the SVGs. The second pattern was a heterogeneous, echogenic monolayer found in the angiographically irregular and diseased sections of the SVGs. Comparison of the in vitro IVUS images with the histopathology of the SVGs showed a strong correlation between the triple-layer structure and fibrointimal proliferation, and between the heterogeneous monolayer and atherosclerosis. In conclusion, IVUS is useful for assessing SVGs and for long-term qualitative monitoring of vein graft disease after CABG.

Coronary Artery Bypass↗