The back-approach technique of endoscopic saphenous vein harvesting in coronary artery bypass grafting.

PURPOSE: One of the concerns during endoscopic saphenous vein harvesting (EVH) in coronary artery bypass grafting (CABG) is injury to the vein or its branches. The cutting edge of bipolar electrocautery scissors, used to divide the side branches of the saphenous vein, can cause vascular injury leading to reduced graft patency. We have developed a novel back-approach technique using a C-ring to divide the wide side branches of the saphenous vein during EVH. The aim of the study was to describe the technique and assess early outcomes of EVH using this technique. The back-approach technique is as follows: (a) insert the C-ring near the target branch, (b) push the C-ring over the proximal aspect of the target branch, (c) twist the C-ring forward to capture the target branch, and (d) cut the target branch by bipolar electrocautery. METHODS: We investigated 169 patients, including 35 women (mean age 70.1 ± 8.9 years), who underwent CABG at our hospital, using a novel EVH technique. The patients were categorized as those who underwent EVH (EVH group, n = 44) or open vein harvesting (OVH) (OVH group, n = 125). This method involves the creation of a small incision (2 cm), sufficient saphenous vein dissection near the skin incision, adequate dissection to separate the vein from the surrounding tissues, and the back-approach technique with C-ring to divide the side branch of the saphenous vein. The primary endpoint was the graft patency rate, and the secondary endpoints were leg wound complications and length of hospitalization. RESULTS: No significant intergroup difference was observed in early patency of saphenous vein graft patency (OVH vs. EVH = 94.7 vs. 95.6%, p = 0.763). The incidence of lower extremity wound lymphorrhea was significantly lesser (OVH: EVH = 16.0: 0.0%, p = 0.005) and the length of hospitalization was also significantly shorter in the EVH group (OVH vs. EVH = 24.2 ± 9.8 vs. 19.0 ± 5.3 days, p = 0.001). CONCLUSIONS: EVH, using the back-approach technique, showed satisfactory short-term results; therefore, this technique performed with C-ring might be effective for vein harvesting during EVH.

Effectiveness of Endovenous Radiofrequency Ablation for Elderly Patients with Varicose Veins of Lower Extremities.

Objective: The purpose of this study was to evaluate safety and effectiveness of endovenous radiofrequency ablation (RFA) for elderly patients. Materials and Methods: We enrolled 140 patients (194 limbs) who underwent RFA for varicose veins of lower extremities. Patients were divided into two groups; elderly patients (more than 75 years old, E-group, n=36) and young patients (under 75 years old, Y-group, n=104), and perioperative data were analyzed and compared between two groups. Results: In E-group, there were more than patients with hypertension, ischemic heart disease, malignant tumor, and cerebrovascular disease. A partial recanalization was observed in only one limb (0.6%) in Y-group. Endovenous heat induced thrombosis (EHIT) was identified four limbs (2.8%) in Y-group and two limbs (4.1%) in E-group. All EHITs were class 1 by Kabnick classification, and they disappeared within one month after interventions, without antithrombotic therapy. No other major complications were observed. There were no significantly differences for preoperative mean venous clinical severity scores (VCSS) (Y : E=4.84 : 4.47) and postoperative VCSS (Y : E=1.16 : 1.19, 0.35 : 0.58, 0.15 : 0.06, 0.05 : 0.06 at 1, 3, 6, 12 months after) in both groups. Conclusion: RFA for elderly patients is a safe and effective strategy for varicose veins of lower extremities.

Preventive Effect of Suvorexant for Postoperative Delirium after Coronary Artery Bypass Grafting.

OBJECTIVE: Suvorexant is an orexin receptor antagonist and is effective in inducing sleep. We hypothesized that Suvorexant would reduce the incidence of postoperative delirium (POD) after coronary artery bypass grafting (CABG). METHODS: We reviewed 88 patients (12 women, mean age: 69.3 ± 2.5 years) who were undergone CABG alone. Patients were divided into two groups; patients received Suvorexant (S group, n = 36), patients not received Suvorexant (N group, n = 52), and the following data were analyzed and compared between two groups. RESULTS: Intensive Care Unit Delirium Screening Checklist Score was significantly lower in S group compared with N group (N:S = 2.0 ± 1.7:0.8 ± 1.0, p = 0.0003). Although POD was present in 11 of 52 patients (21.2%) in N group, one patient (2.8%) developed in S group (p = 0.008). In S group, both intensive care unit stay (N:S = median 6:5 days, p = 0.001) and hospital stay (N:S = median 23:20 days, p = 0.035) were significantly shorter than in N group. CONCLUSIONS: Suvorexant might reduce incidence of POD in patients undergone CABG.

Usefulness of sternal closure with bioresorbable plate in respiratory function after coronary artery bypass grafting.

OBJECTIVE: The aim of our study is to investigate that sternal reconstruction using bioresorbable plate in median sternotomy may reduce postoperative respiratory dysfunction when compared with wire cerclage only. METHODS: We reviewed 107 patients who were undergone coronary artery bypass grafting with median sternotomy. Patients were divided into two groups; patients underwent sternal reconstruction with bioresorbable plate and wire cerclage (S group, n = 56), patients with wire cerclage only (N group, n = 51), and perioperative respiratory function and postoperative pain score data were analyzed and compared between two groups. RESULTS: There was no significantly difference in preoperative respiratory function in both groups. However, in postoperative change rate of respiratory function, N group had significant decrease compared with S group in vital capacity (VC) (N: S = 74.8 ± 12.4: 85.2 ± 14.8%, p = 0.020), VC as a percentage of predicated VC (N: S = 75.0 ± 12.5: 86.4 ± 15.1%, p = 0.012), and forced expiratory volume in the first second (N: S = 73.7 ± 9.2: 85.3 ± 16.4%, p = 0.012). In Prince Henry Pain Scale, there were significantly more in N group compared with S group (N: S = 3.4 ± 1.0: 2.6 ± 1.4, p = 0.003). CONCLUSION: Sternal fixation with bioresorbable plate could reduce impairment of postoperative respiratory function in comparison to wire cerclage only.

Mid-Term Report on the Safety and Effectiveness of Endovenous Radiofrequency Ablation for Varicose Veins.

Objective: Endovenous radiofrequency ablation (RFA), a relatively new technique for treating great saphenous varicose veins, is less invasive compared with stripping surgery. This study examined the mid-term safety and effectiveness of RFA for varicose veins. Materials and Methods: We enrolled 104 patients (147 limbs) who underwent RFA for varicose veins of the lower extremities (females, 67; 64.4%). The mean age was 68.9±9.2 years (39-85 years). In 121 limbs (82.3%), there were great saphenous veins. All patients were observed as outpatients for 12 months after the procedure. RFA was performed using ClosureFast™ catheters with tumescent local anesthesia. Results: There was 99.4% occlusion of the treated veins, and partial recanalization was observed in one limb. Endovenous heat-induced thrombosis (EHIT) was identified in five limbs (3.4%). All EHITs were class 1 according to the Kabnick classification, and they disappeared within 1 month of the intervention without antithrombotic therapy. No other major complications were observed. Mean venous clinical severity scores improved from 5.31 at the baseline to 1.10, 0.39, 0.14, and 0.06 at 1, 3, 6, and 12 months, respectively. Conclusion: RFA is a safe and effective strategy for varicose veins of the lower extremities.

[Catheter-induced Pulmonary Artery Injury and Pseudoaneurysm after Cardiac Surgery].

The pulmonary artery catheter( PAC) has been used for hemodynamic monitoring in patients undergoing cardiac surgery. Pulmonary artery injury and pseudoaneurysm formation are the most serious and fatal complications of PAC. A 73-year-old female with aortic stenosis and angina underwent aortic valve replacement and coronary artery bypass grafting. PAC was inserted without difficulty before cardiac surgery in the operating room. The operation proceeded uneventfully. On the 1st postoperative day, massive hemoptysis suddenly occurred in the intensive care unit. The patient was treated with mechanical ventilation with positive end expiratory pressure. An enhanced computed tomography scan showed a pulmonary artery pseudoaneurysm, whith was successfully occluded by transcatheter arterial embolization. The patient was discharged in good health.

[Aortic valve replacement in a patient with antiphospholipid syndrome; report of a case].

A 76-year-old woman with primary antiphospholipid syndrome (APS) was referred to our hospital due to severe aortic valve stenosis. We performed aortic valve replacement using a bioprosthetic valve. Her postoperative course was uneventful. She was discharged in good health on postoperative day 33. As for cardiovascular operations in APS patients, high rates have been reported of perioperative mortality and thromboembolic and bleeding events. Perioperative management of anticoagulation must be strict.

Toxicogenomic biomarkers for renal papillary injury in rats.

Renal papillary injury is a common side effect observed during nonclinical and clinical investigations in drug development. The present study aimed to identify genomic biomarkers for early and sensitive detection of renal papillary injury in rats. We hypothesized that previously identified genomic biomarkers for tubular injury might be applicable for the sensitive detection of papillary injury in rats. We selected 18 genes as candidate biomarkers for papillary injury based on previously published studies and analyzed their expression profiles by RT-PCR in each kidney region, namely the cortex, cortico-medullary junction, and papilla in various nephrotoxicity models. Comparative analysis of gene expression profiles revealed that some genes were commonly upregulated or downregulated in the renal papilla, reflecting papillary injuries induced by 2-bromoethylamine hydrobromide, phenylbutazone, or n-phenylanthranilic acid. By applying receiver operator characteristics analysis, six candidate biomarkers were identified and their usefulness was confirmed by using an independent data set. The three top-ranked genes, Timp1, Igf1, and Lamc2, exhibited the best prediction performance in an external data set with area under the curve (AUC) values of greater than 0.91. An optimized support vector machine model consisting of three genes achieved the highest AUC value of 0.99. In conclusion, even though definitive validation studies are required for the establishment of their usefulness and reliability, these identified genes may prove to be the most promising candidate genomic biomarkers of renal papillary injury in rats.

Toxicogenomic multigene biomarker for predicting the future onset of proximal tubular injury in rats.

Drug-induced renal tubular injury is a major concern in the preclinical safety evaluation of drug candidates. Toxicogenomics is now a generally accepted tool for identifying chemicals with potential safety problems. The specific aim of the present study was to develop a model for use in predicting the future onset of drug-induced proximal tubular injury following repeated dosing with various nephrotoxicants. In total, 41 nephrotoxic and nonnephrotoxic compounds were used for the present analysis. Male Sprague-Dawley rats were dosed orally or intravenously once daily. Animals were exposed to three different doses (low, middle, and high) of each compound, and kidney tissue was collected at 3, 6, 9, and 24 h after single dosing, and on days 4, 8, 15, and 29 after repeated dosing. Gene expression profiles were generated from kidney total RNA using Affymetrix DNA microarrays. Filter-type gene selection and linear classification algorithms were employed to discriminate future onset of proximal tubular injury. We identified genomic biomarkers for use in future onset prediction using the gene expression profiles determined on day 1, when most of the nephrotoxicants had yet to produce detectable histopathological changes. The model was evaluated using a five-fold cross validation, and achieved a sensitivity of 93% and selectivity of 90% with 19 probes. We also found that the prediction accuracy of the optimized model was substantially higher than that produced by any of the single genomic biomarkers or histopathology. The genes included in our model were primarily involved in DNA replication, cell cycle control, apoptosis, and responses to oxidative stress and chemical stimuli. In summary, our toxicogenomic model is particularly useful for predicting the future onset of proximal tubular injury.

Prediction model of potential hepatocarcinogenicity of rat hepatocarcinogens using a large-scale toxicogenomics database.

The present study was performed to develop a robust gene-based prediction model for early assessment of potential hepatocarcinogenicity of chemicals in rats by using our toxicogenomics database, TG-GATEs (Genomics-Assisted Toxicity Evaluation System developed by the Toxicogenomics Project in Japan). The positive training set consisted of high- or middle-dose groups that received 6 different non-genotoxic hepatocarcinogens during a 28-day period. The negative training set consisted of high- or middle-dose groups of 54 non-carcinogens. Support vector machine combined with wrapper-type gene selection algorithms was used for modeling. Consequently, our best classifier yielded prediction accuracies for hepatocarcinogenicity of 99% sensitivity and 97% specificity in the training data set, and false positive prediction was almost completely eliminated. Pathway analysis of feature genes revealed that the mitogen-activated protein kinase p38- and phosphatidylinositol-3-kinase-centered interactome and the v-myc myelocytomatosis viral oncogene homolog-centered interactome were the 2 most significant networks. The usefulness and robustness of our predictor were further confirmed in an independent validation data set obtained from the public database. Interestingly, similar positive predictions were obtained in several genotoxic hepatocarcinogens as well as non-genotoxic hepatocarcinogens. These results indicate that the expression profiles of our newly selected candidate biomarker genes might be common characteristics in the early stage of carcinogenesis for both genotoxic and non-genotoxic carcinogens in the rat liver. Our toxicogenomic model might be useful for the prospective screening of hepatocarcinogenicity of compounds and prioritization of compounds for carcinogenicity testing.

A toxicogenomic approach for identifying biomarkers for myelosuppressive anemia in rats.

Myelosuppressive anemia is a serious side effect associated with several drugs. Thus, there is an increasing demand for sensitive biomarkers for the early detection of myelosuppressive anemia during toxicological studies. We applied a toxicogenomic approach to identify useful biomarker genes reflecting myelosuppressive anemia in the rat liver. Expression of the hemoglobin beta chain complex (Hbb), aminolevulinic acid synthase 2 (Alas2), and cell division cycle 25 homolog B (Cdc25b) genes changed as a result of anemia induced by the myelosuppressive agents linezolid, cisplatin, and carboplatin, suggesting that these genes may be suitable biomarkers. Moreover, evaluation of perfused and unperfused livers indicated that changes in the expression of these genes originate in circulating reticulocytes in the liver. Erythroid differentiation-associated changes in expression of the Hbb, Alas2, and Cdc25b genes were confirmed in vitro using Friend leukemia cells. In conclusion, our current research provides novel evidence that gene expression in circulating reticulocytes contained in the liver changes dramatically under myelosuppressive conditions. While further large-scale validation studies are needed, our results indicate that the genes we identified might be useful biomarkers for the sensitive detection of myelosuppressive anemia in rats.

Comparative nephrotoxicity of Cisplatin and nedaplatin: mechanisms and histopathological characteristics.

The antineoplastic platinum complexes cisplatin and its analogues are widely used in the chemotherapy of a variety of human malignancies, and are especially active against several types of cancers. Nedaplatin is a second-generation platinum complex with reduced nephrotoxicity. However, their use commonly causes nephrotoxicity due to a lack of tumor tissue selectivity. Several recent studies have provided significant insights into the molecular and histopathological events associated with nedaplatin nephrotoxicity. In this review, we summarize findings concerning the renal histopathology and molecular pathogenesis induced by antineoplastic platinum complexes, with a particular focus on the comparative nephrotoxicity of cisplatin and nedaplatin in rats.

Spontaneous Erythroid Leukemia in a 7-Week-Old Crl:CD (SD) Rat.

A young male Crl:CD (SD) rat with erythroid leukemia that presented with emaciation, abdominal distension and a pale visible mucosal membrane was euthanized at 7 weeks of age. At necropsy, enlargement of liver, spleen and pancreatic lymph node was noted. Analysis of blood smear samples revealed many mono- or binucleated erythroblasts that had PAS-positive vacuoles in the cytoplasm. Histopathologically, neoplastic proliferation of atypical cells was observed in the hepatic sinusoids, splenic red pulp, bone marrow, pancreatic lymph node, kidney and lung. Neoplastic cells showed a round to spindle shape, and some neoplastic cells had deeply stained small nuclei and small cytoplasms and resembled erythroblasts. Immunohistochemically, many neoplastic cells were positive for hemoglobin. To our knowledge, this is the first report of erythroid leukemia in a rat of this age. The observed features were similar to those of pure erythroid leukemia in humans.

The Japanese toxicogenomics project: application of toxicogenomics.

Biotechnology advances have provided novel methods for the risk assessment of chemicals. The application of microarray technologies to toxicology, known as toxicogenomics, is becoming an accepted approach for identifying chemicals with potential safety problems. Gene expression profiling is expected to identify the mechanisms that underlie the potential toxicity of chemicals. This technology has also been applied to identify biomarkers of toxicity to predict potential hazardous chemicals. Ultimately, toxicogenomics is expected to aid in risk assessment. The following discussion explores potential applications and features of the Japanese Toxicogenomics Project.

Identification of genomic biomarkers for concurrent diagnosis of drug-induced renal tubular injury using a large-scale toxicogenomics database.

Drug-induced renal tubular injury is one of the major concerns in preclinical safety evaluations. Toxicogenomics is becoming a generally accepted approach for identifying chemicals with potential safety problems. In the present study, we analyzed 33 nephrotoxicants and 8 non-nephrotoxic hepatotoxicants to elucidate time- and dose-dependent global gene expression changes associated with proximal tubular toxicity. The compounds were administered orally or intravenously once daily to male Sprague-Dawley rats. The animals were exposed to four different doses of the compounds, and kidney tissues were collected on days 4, 8, 15, and 29. Gene expression profiles were generated from kidney RNA by using Affymetrix GeneChips and analyzed in conjunction with the histopathological changes. We used the filter-type gene selection algorithm based on t-statistics conjugated with the SVM classifier, and achieved a sensitivity of 90% with a selectivity of 90%. Then, 92 genes were extracted as the genomic biomarker candidates that were used to construct the classifier. The gene list contains well-known biomarkers, such as Kidney injury molecule 1, Ceruloplasmin, Clusterin, Tissue inhibitor of metallopeptidase 1, and also novel biomarker candidates. Most of the genes involved in tissue remodeling, the immune/inflammatory response, cell adhesion/proliferation/migration, and metabolism were predominantly up-regulated. Down-regulated genes participated in cell adhesion/proliferation/migration, membrane transport, and signal transduction. Our classifier has better prediction accuracy than any of the well-known biomarkers. Therefore, the toxicogenomics approach would be useful for concurrent diagnosis of renal tubular injury.

Echographic detection of diethylnitrosamine-induced liver tumors in rats and the effect of the intratumoral injection of an inhibitor of c-Jun N-terminal kinase.

BACKGROUND AND AIM: There have so far been few reports describing echographic studies of chemically-induced carcinogenesis in rodent livers. Using echography, we observed diethylnitrosamine-induced liver tumors in rats and examined the effect of an intratumoral injection of an inhibitor of c-Jun N-terminal kinase. METHODS: Male Wistar rats were given 100 ppm of diethylnitrosamine for 6 weeks and their liver nodules were examined by echography weekly. The size of the nodules was measured and they were examined histologically. The effect of SP600125, an inhibitor of c-Jun N-terminal kinase, on the growth of rat hepatoma cell line McA-RH7777 was tested in vitro. Thereafter, SP600125 was injected into the liver nodules under echographic guidance in vivo and the changes in the proliferating cell nuclear antigen expression and size of the nodules were examined. RESULTS: The four distinct lobes of rat livers were clearly observed by transabdominal echography. The nodules in the livers were first detected 6 weeks after the treatment began, when they were as small as 1.6 mm in diameter. The nodules thereafter became more malignant histologically as they grew larger than 4 mm. SP600125 decreased the expression of proliferating cell nuclear antigen and the growth of McA-RH7777 cells. After SP600125 was injected in vivo, the proliferating cell nuclear antigen level and the growth rate of the rat liver nodules all significantly decreased. CONCLUSIONS: Our results indicate that echography is quite useful for follow-up studies of liver carcinogenesis in rats, and c-Jun N-terminal kinase might be another therapeutic target in liver neoplasms.

Time course of the change and amelioration of nedaplatin-induced nephrotoxicity in rats.

Nedaplatin (NDP) is a second-generation antineoplastic platinum complex, with reduced nephrotoxicity. Two experiments were conducted to characterize the time course of changes of its nephrotoxicity and to further evaluate whether hydration is useful for amelioration of nephrotoxicity. In the first experiment, 8-week-old male rats treated with 6 or 9 mg kg(-1) NDP at a single intravenous dose were killed 2, 4, 7 and 14 days after dosing. In the second experiment, nonhydrated (Nhyd) or hydrated (Hyd) rats, treated with a single intravenous dose of 20 mg kg(-1) NDP, were killed 7 days after dosing. Besides renal function and histopathological examinations, the urinary excretion of platinum was measured. Histopathologically, NDP-induced nephrotoxicity was initially characterized by single cell and/or focal necrosis in the epithelium of distal tubules and collecting ducts as well as proximal tubules. In the later stage, subsequent cystic dilatation and regeneration occurred in these affected tubules, but incomplete tissue repair was still observed in the kidney 14 days after dosing. However, NDP-induced nephrotoxicity was dramatically reduced by hydration, while it had no clear effects on myelotoxicity. Measurement of urinary platinum excretion revealed that the total amount of platinum excretion was significantly higher in Hyd-NDP rats than that in Nhyd-NDP rats. In terms of urinary concentration, Hyd-NDP rats showed a lower concentration compared with that in Nhyd-NDP rats. The current results suggest that NDP has the potential risk to cause nephrotoxicity at a human therapeutic dose without hydration and that pre- and post-hydration at dosing can ameliorate this nephrotoxicity.

Comparative analysis of gene expression between renal cortex and papilla in nedaplatin-induced nephrotoxicity in rats.

To elucidate the mechanism of nephrotoxicity caused by anti-neoplastic platinum complex, nedaplatin (NDP), treatment with a particular focus on the renal papillary toxicity, we analysed the gene expression profiles of two renal regions, the cortex (RC) and the papilla (RP) in rat kidneys. Male Wistar rats received a single administration of 10 mg/kg intravenous NDP or vehicle alone (5% xylitol solution) and were sacrificed six days later. The kidneys were dissected into the RC and RP and used for histopathological and microarray analyses. Histopathologically, NDP caused characteristic renal lesions, such as necrosis, single cell necrosis (with TUNEL TdT-mediated dUTP-biotin nick end labelling-positive) and regeneration/hyperplasia of the epithelial cells in both renal regions. Global gene expression analysis revealed that several genes involved in various functional categories were commonly deregulated in both renal regions, such as apoptosis, cell cycle regulation, DNA metabolism, cell migration/adhesion and cytoskeleton organization or genes induced as a perturbation of oxidative status and calcium homeostasis. Comparative analysis of gene expression between RC and RP revealed that genes encoding several subtypes of cytokeratins were identified as being specifically overexpressed in RP by the NDP treatment. Differential expression patterns of these selected genes observed by microarray analysis were further confirmed by quantitative real time RT-PCR and immunohistochemistry, which demonstrated increased expression of cytokeratins (CKs) 14 and 19 at the epithelium covering RP and/or collecting duct epithelium. Overall, the results contribute to understanding the renal molecular events of NDP-induced nephrotoxicity including novel potential biomarker genes encoding CKs 14 and 19 that may serve as indicators of renal papillary toxicity.

Advantages to the use of rodent hepadnavirus core proteins as vaccine platforms.

The hepatitis B core antigen (HBcAg) has been proposed as a useful particulate carrier platform for poorly immunogenic peptidic and carbohydrate B cell epitopes. However, biochemical and immunologic impediments have plagued this technology. Specifically, the "assembly" problem characterized by the low yield of unstable hybrid particles resulting from the insertion of foreign sequences and the "pre-existing immunity" problem due to the fact that the HBcAg is derived from a human pathogen have limited the development of this carrier technology. As a means of addressing the "pre-existing immunity" problem we have used the core proteins from the rodent hepdnaviruses. A number of advantages to the use of the rodent hepadnaviral core proteins as opposed to the HBcAg for vaccine design were defined including: equal or superior immunogenicity at the T and B cell levels; the use of the rodent core proteins does not compromise the anti-HBc diagnostic assay; the efficacy of the rodent core proteins as vaccine carriers will not be limited by pre-existing anti-HBc antibodies that are present in previously and currently HBV-infected persons; and the HBcAg-specific tolerance present in HBV chronic carriers can be circumvented by the use of the rodent core proteins.

Microbubble-induced increase in ablation of liver tumors by high-intensity focused ultrasound.

We studied the possibility of using high-intensity focused ultrasound (HIFU) together with a microbubble agent to treat hepatocellular carcinoma. Development of liver tumors in rats was induced by administration of Dimethylnitrosamin (100ppm). Rats with liver tumors were anesthetized, underwent laparotomy, and were given the microbubble agent Levovist or saline intravenously. After the injection, the liver was exposed to HIFU for 30s (2.18MHz, 600W/cm(2), 40mm in diameter). Immediately after HIFU exposure, ultrasound images of the HIFU area were evaluated. Then the liver was excised and the volume of coagulated tissue was measured. The mean volumes of hyperechoic areas after HIFU were as follows (mm(3), Levovist versus saline: 355.3+/-180.7 versus 47.4+/-35.6, P<0.001, n=13). The volumes of liver tissue coagulated by HIFU were as follows (mm(3), Levovist versus saline: 275.3+/-120.0 versus 60.1+/-23.6, P<0.001, n=13). On microscopic examination of areas exposed to HIFU, implosion cysts were seen, and many cancer cells were found to have been destroyed completely (loss of cell membranes or nuclei). In conclusion, the microbubble agent Levovist can increase the volume of tissue coagulated by HIFU.