Neoadjuvant chemoradiotherapy versus neoadjuvant chemotherapy followed by minimally invasive esophagectomy for locally advanced esophageal squamous cell carcinoma: a prospective multicenter randomized clinical trial.

BACKGROUND: Neoadjuvant therapy is recommended for locally advanced esophageal cancer, but the optimal strategy remains unclear. We aimed to evaluate the safety and efficacy of neoadjuvant chemoradiotherapy (nCRT) versus neoadjuvant chemotherapy (nCT) followed by minimally invasive esophagectomy (MIE) for locally advanced esophageal squamous cell carcinoma (ESCC). PATIENTS AND METHODS: Eligible patients staged as cT3-4aN0-1M0 ESCC were randomly assigned (1 : 1) to the nCRT or nCT group stratified by age, cN stage, and centers. The chemotherapy, based on paclitaxel and cisplatin, was administered to both groups, while concurrent radiotherapy was added for the nCRT group; then MIE was carried out. The primary endpoint was 3-year overall survival. This study is registered with ClinicalTrials.gov (NCT03001596). RESULTS: A total of 264 patients were eligible for the intention-to-treat analysis. By 30 November 2021, 121 deaths had occurred. The median follow-up was 43.9 months (interquartile range 36.6-49.3 months). The overall survival in the intention-to-treat population was comparable between the nCRT and nCT strategies [hazard ratio (HR) 0.82, 95% confidence interval (CI) 0.58-1.18; P = 0.28], with a 3-year survival rate of 64.1% (95% CI 56.4% to 72.9%) versus 54.9% (95% CI 47.0% to 64.2%), respectively. There were also no differences in progression-free survival (HR 0.83, 95% CI 0.59-1.16; P = 0.27) and recurrence-free survival (HR 1.07, 95% CI 0.71-1.60; P = 0.75), although the pathological complete response in the nCRT group (31/112, 27.7%) was significantly higher than that in the nCT group (3/104, 2.9%; P < 0.001). Besides, a trend of lower risk of recurrence was observed in the nCRT group (P = 0.063), while the recurrence pattern was similar (P = 0.802). CONCLUSIONS: NCRT followed by MIE was not associated with significantly better overall survival than nCT among patients with cT3-4aN0-1M0 ESCC. The results underscore the pending issue of the best strategy of neoadjuvant therapy for locally advanced bulky ESCC.

Design of super-strong and thermally stable nanotwinned Al alloys via solute synergy.

Al alloys have widespread industrial applications. However, their mechanical strength is often much lower than steels. Here, we investigate the influence of solutes on achieving ultrahigh strength and thermal stability of nanotwinned Al alloys. In situ micropillar compression tests show the addition of a small amount of Ti can significantly increase the mechanical strength of Al-Ni alloys to 2 GPa. Deformation induced detwinning, Ni segregation and grain coarsening as discovered in binary Al-Ni alloys are mostly absent in the ternary Al-Ni-Ti alloys. Moreover, the ternary Al-Ni-Ti alloys have outstanding thermal stability. Density function theory calculations reveal the synergetic pinning effect of Ni-Ti solute pairs on incoherent twin boundaries. This study demonstrates that the proper selection of synergistic solute pairs is critical to improve the thermal stability and mechanical properties of nanotwinned Al alloys.

[Protective effect and mechanism of mild hypothermia on liver injury after cardiopulmonary resuscitation in pigs].

Objective: To investigate the effect of mild hypothermia therapy on liver after cardiopulmonary resuscitation. Methods: Thirty-three inbred Chinese Wuzhishan (WZS) minipigs, weighted (28±2) kg, were used to establish a ventricular fibrillation model. And 30 animals survived after cardiopulmonary resuscitation reached basic life support. The surviving animals were randomly divided into two groups: mild hypothermia group (group M, n=15) and conventional treatment group (group C, n=15). All the animals were observed for 24 hours. Blood samples were extracted at baseline, 0.5, 1, 2, 4, 6, 12 and 24 h after successful resuscitation. The concentrations of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were detected at the time points. The enzyme-linked immunosorbent assay (ELISA) was used to detect the concentrations of interleukin-6 (IL-6) and tumour necrosis factor-alpha (TNF-α). The data were compared between the two groups, LSD test was used when the variance was homogeneous, and Tamhane T2 test was used when the variance was uneven. Results: Eleven pigs (73.3%) in the group M and 8(53.3%) in the group C survived at 24 h after successful resuscitation, with no statistically significant difference between the two groups (χ(2)=1.229, P=0.225). After successful resuscitation, the AST, ALT increased in both group but less in M group (all P<0.05). After successful resuscitation, the concentrations of TFN-α and IL-6 in the blood increased in both groups, reached the peak at 4h, and then decreased gradually. The concentrations of TFN-α in group M were lower than those in group C at 0.5, 2, 4 and 6 h after successful resuscitation (t=0.01, 0.01, 0.87, 0.86, all P<0.05). The concentrations of IL-6 in the group M were lower than those in group C at 0.5, 1, 2 and 4 h after successful resuscitation (t=0.23, 0.78, 0.11, 0.80, all P<0.05). Conclusions: After successful resuscitation, the release of inflammatory mediators, such as TNF-α and IL-6, and cell apoptosis may involve in liver ischemia reperfusion injury. After successful resuscitation, the liver undergoes ischemia-reperfusion injury, which may be related to the release of inflammatory mediators such as TNF-α and IL-6. Mild hypothermia therapy can prevent the release of TNF-α, IL-6 to reduce the degree of liver damage after resuscitation.

Experimental study of a compact piezoelectric micro-perforated panel absorber with adjustable acoustic property.

This work aims to investigate the acoustic characteristics of a piezoelectric micro-perforated panel (MPP) absorber, which is made of a perforated polyvinylidene fluoride (PVDF) film with a backed airgap of 2 cm, as a combination of an active component and passive absorber. In addition to its inherent passive dissipation, as the PVDF-MPP was driven with proper voltages and oscillation frequencies, sound absorption coefficients of the absorber adjacent to the driving frequencies were significantly increased. Compared with mostly previous reported hybrid passive-active absorbers, this one is more compact, and its acoustic property is adjustable, it may provide an approach to achieve intelligent noise control.

Ultra-strong nanotwinned Al-Ni solid solution alloys with significant plasticity.

Twin boundaries have been proven effective for strengthening metallic materials while maintaining plasticity. Al, however, has low twinning propensity due to its high stacking fault energy. Here we show, by using a small amount of Ni solutes, high-density twin boundaries and stacking faults in sputtered Al-Ni solid solution alloys. Density function theory calculations show that the Ni solute facilitates the formation of stacking faults and stabilizes nanotwins in Al-Ni solid solution alloys. In situ micropillar compression studies reveal a high flow stress (exceeding 1.7 GPa), comparable to high strength martensitic steels and Ni alloys. Furthermore, significant plasticity was observed in these nanotwinned Al-Ni alloy films due to the existence of high density twin boundaries and 9R phase.

[Effect of moluodan on gastric secretion in atrophic gastritis rats].

Objective: To investigate the effect of moluodan on gastric secretion and the underlying mechanism of moluodan in treating atrophic gastritis. Method: According to the random number table, 120 healthy male specific-pathogen-free (SPF) Sprague-Dawley rats were divided into 4 groups: control group, model group, moluodan low-dose group, and moluodan high-dose group, with 30 rats in each group. The control group was administered with normal saline 2 ml/d by gavage, the other three groups were administered with 2% sodium salicylate 1 ml/d, 20 mol/L sodium deoxycholate 1 ml/d, and N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) 200 mg/kg for every 10 days. And 16 weeks later, the control group and model group were treated with normal saline 2 ml/d by gavage, meanwhile the moluodan low-dose group was treated with moluodan 0.9 g·kg-1·d-1and the high-dose group was treated with moluodan 1.8 g·kg-1·d-1, continuously for 12 weeks. Ten rats of each group were sacrificed at the end of 4, 8, 12 weeks. The effect of moluodan on atrophic gastritis was observed. The secretion function of gastric mucosa was assessed through detecting the numbers of gastrin-secreting cells (G cells) and somatostatin-secreting cell (D cells) in gastric mucosa using immunochemical staining, and measuring the serum levels of gastrin (GAS) and somatostatin (SS) using enzyme-linked immunosorbent assay (ELISA). Results: After 8 weeks, the numbers of G and D cells in gastric mucosa in the moluodan high-dose group significantly increased compared with the model group[(0.617±0.114) vs (0.476±0.116) cells/mm2, (0.504±0.084) vs (0.369±0.148) cells/mm2, both P<0.05]; the numbers of G and D cells in gastric mucosa in the low-dose group increased after 12-week's treatment[(0.674±0.129) vs (0.528±0.103) cells/mm2, (0.526±0.087) vs (0.371±0.058) cells/mm2, both P<0.05]. The serum GAS levels increased markedly after 8 weeks in the moluodan high-dose group and after 12 weeks in the low-dose group[(1.313±0.080) ng/ml vs (0.964±0.080) ng/ml, (1.202±0.124) ng/ml vs (0.909±0.054) ng/ml, both P<0.01]; the serum SS levels in both high- and low-dose groups were significantly lower than in the model group after 8-week's treatment[(2.376±0.199) ng/ml, (2.238±0.155) ng/ml vs (2.605±0.183) ng/ml, both P<0.05]. Conclusion: Moluodan may treat atrophic gastritis by repairing G and D cells in gastric mucosa and thus increasing serum levels of GAS.

Mutational analysis of mitochondrial tRNA genes in patients with lung cancer.

Mutations in mitochondrial tRNA (mt-tRNA) genes have been found to be associated with various diseases including lung cancer. To understand the possible relationship between mtRNA mutations and lung cancer, we sequenced the 22 mt-tRNA genes from 200 lung cancer blood samples, as well as 100 healthy subjects. As a result, five mutations were identified including the tRNAAla T5655C, tRNAArg T10454C, tRNALeu(CUN) A12330G, tRNASer(UCN) T7505C and tRNAThr G15927A. These mutations were absent in the healthy subjects. These mutations and polymorphisms were localized at the highly conserved nucleotides of the corresponding mitochondrial tRNAs, which are critical for the tRNA steady state level and may result in failure in the tRNA metabolism. Moreover, through the application of the pathogenicity scoring system, we found that only the T10454C mutation should be classified as a "neutral polymorphism," while the other mutations were regarded as "definitely pathogenic." Taken together, our data indicate that tRNA genes are the hot-spots for pathogenic mutations associated with lung cancer. Our findings may provide valuable information for pathophysiology, management and genetic counseling of lung cancer.

Case Report Unicentric Castleman disease located in the anterior mediastinum misdiagnosed as invasive thymoma: a case report.

Castleman disease is a rare lymphoproliferative disorder of unknown etiology. The localized form, which usually presents as a slow-growing mass, is most commonly located in the mediastinum. Invasion of the vena anonyma by a mass has rarely been reported. We herein describe a case of initially misdiagnosed invasive thymoma in a 72-year-old woman, but postoperatively proven to have anterior mediastinal Castleman disease with invasion of the vena anonyma.

Interferon-ß gene-modified human bone marrow mesenchymal stem cells attenuate hepatocellular carcinoma through inhibiting AKT/FOXO3a pathway.

OBJECTIVE: This study aims to investigate the using of bone marrow mesenchymal stem cells (BMSCs) genetically engineered to produce interferon-ß (IFN-ß) as a gene delivery system to treat hepatocellular carcinoma (HCC) in vitro and in vivo. METHODS: To measure the effects on tumour cell growth in vitro, IFN-ß-producing BMSCs (BMSC/IFN-ß) were co-cultured with the HCC cell line HepG2 and Huh7. Enzyme-linked immunosorbent assay (ELISA) was used to detect the IFN-ß secretion in the BMSC culture condition medium (CM). The effect of BMSC/IFN-ß on HCC cells proliferation was examined both in vitro and in vivo by using MTT, colony formation assay, BrdU staining, cell cycle analysis, and xenografted NOD/SCID mouse tumour model. To examine the impact of BMSC/IFN-ß on the AKT/FOXO3a signalling, RT-PCR and western blotting were performed. RESULTS: The BMSC/IFN-ß cells can stably secrete high levels of IFN-ß. Both MTT and colony forming assay showed that HCC cells had a lower growth rate when cultured in BMSC/IFN-ß-CM as compared with that in BMSC/vector-CM or DMEM culture group. Co-culture with BMSC/IFN-ß-CM dramatically decreased the percentages of cells with incorporated BrdUrd. In BMSC/IFN-ß-CM-treated HCC cells, the proportion of G1-phase cells increased but it decreased in the S phase of the cell. The BMSC/IFN-ß inhibited HCC growth in NOD/SCID mice and proved the survival period of these mice. Compared with the control group, p21 and p27 expression of hepatoma cells increased, whereas cyclin D1 and phosphorylation of Rb expression decreased when co-cultured with BMSC/IFN-ß-CM. It was associated with suppression of Akt activity and enhanced transcriptional activity of FOXO3a. CONCLUSION: The IFN-ß gene-modified BMSCs can effectively inhibit the proliferation of HCC cells in vitro and in vivo through inhibiting AKT/FOXO3a pathway. These results indicate that BMSC/IFN-ß are a powerful anticancer cytotherapeutic tool for HCC.

Down-regulation of iASPP in human hepatocellular carcinoma cells inhibits cell proliferation and tumor growth.

The oncoprotein inhibitory member of the ASPP family (iASPP) is a key inhibitor of the p53 tumor suppressor and is upregulated in patients with acute leukemia and breast carcinoma. To investigate the effect of iASPP inhibition on the proliferation of hepatocellular carcinoma cells, a recombinant lentivirus vector expressing a small interfering RNA (siRNA) against iASPP gene expression was constructed and used to infect human hepatocellular carcinoma cells (HepG2 and Hep3B). The results showed that iASPP mRNA and protein levels were significantly down-regulated in both cells infected with the siRNA against iASPP. siRNA-mediated down-regulation of iASPP repressed tumor cell proliferation and colony formation in vitro and induced a growth delay of the tumor in vivo, suggesting that iASPP plays an important role in the proliferation of hepatocellular carcinoma cells. iASPP may be a valuable candidate target gene in hepatocellular carcinoma therapy.

Regeneration of Acacia mangium through somatic embryogenesis.

Somatic embryogenesis and whole plant regeneration were achieved in callus cultures derived from immature zygotic embryos of Acacia mangium. Embryogenic callus was induced on MS medium containing combinations of TDZ (1-2 mg/l), IAA (0.25-2 mg/l) and a mixture of amino acids. Globular embryos developed on embryogenic callus cultured on the induction medium. Nearly 42% of embryogenic cultures with globular embryos produced torpedo- and cotyledonary-stage embryos by a two-step maturation phase. The first stage occurred on 1/2-strength MS basal medium containing 30 g/l sucrose and 5 mg/l GA3 followed by the second stage on 1/2-strength MS basal medium containing 50 g/l sucrose. Of the cotyledonary-stage somatic embryos, 11% germinated into seedlings that could be successfully transferred to pots. Light- and scanning electron microscopy showed that the somatic embryos originated from single cells of the embryogenic callus. Further, a single cell layer could be detected beneath the developing somatic embryos that appeared to be a demarcation layer isolating the somatic proembryonic structure from the rest of the maternal callus. A suspensor-like structure connected the globular embryos to the demarcation layer. This is the first successful report of plant regeneration through somatic embryogenesis for this economically important tropical forest species.

[The chemical degradation of lipopolysaccharides from oral anaerobes]

OBJECTIVE:To evaluate the effect of drug on chemical degradation of lipopolysaccharide (LPS) from oral anaerobes.METHODS:LPSs from porphyromonas gingivalis (Pg),bacteroides fragilis (Bf) and fusobacteria nucleatum (Fn) were extracted by the hot phenol-water method and purified by the phenol-chloroform-petroleum ether procedure.1.0 ml (200microg) various LPSs were incubated with 2.0 ml various drugs at 37degrees centigrade for 15 or 30 minutes in vitro,respectively.The chemical degradation of LPS was quantitated by limulus synthetic chromogenic substrated method after dialysis.RESULTS:The order of degradation was 30% hydrogen peroxide (H),50% citric acid (C),garlic guice (G),1:1 diluted G,25% C and 3% H,and their efffcts were dose dependent and were time dependent except H but the effect of lysozyme was minimal.CONCLUSION:The study may imply that the dose and the mechanism of various drugs on LPS degradation are different and remains to be elucidated.

Role of dNTPs in mutagenesis.

The induced mutation frequency by alkylating mutagen glycidyl methacrylate (GMA) and N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) was investigated with or without perturbation of deoxyribonucleoside triphosphate (dNTP) pools; the influence of short treatment at different concentrations of GMA or MNNG on dNTP pools was also explored. The results indicated that the induced mutation frequency increased greatly at high dosages of mutagen (GMA approximately 64 micrograms/ml, MNNG approximately 8 micrograms/ml) and the perturbation on dNTP pools was carried out before the treatment of mutagen; the short treatment with mutagen could induce distinct fluctuations of dNTP pools, but different mutagen might have different effects on dNTP pools. According to the results of the present study and other reports in literature, we conclude that dNTP pools may be the targets of alkylating mutagens and the fluctuations of dNTP pools are closely associated with mutagenesis.

Role of deoxyribonucleoside triphosphates (dNTPs) in cell transformation.

Deoxyribonucleoside triphosphate (dNTP) pools were measured in normal BALB/c3T3 cells, transformation-treated cells and transformed cells with reverse-phase HPLC. The fluctuation of dNTP pools was similar after transformation treatment with alkylating mutagen glycidyl methacrylate (GMA) or Nmethyl-N'-nitro-N-nitrosoguanidine (MNNG). However, the gap between deoxyguanosine triphosphate + deoxyadenosine triphosphate (dGTP + dATP) pools and deoxythymidine triphosphate + deoxycytidine triphosphate (dTTP + dCTP) pools was greatly intensified. The measurements also indicated that the dNTP pools in transformed cells were quite different from those in normal cells. The results suggested that dNTP pools may play an important role in cell transformation.

Smooth excimer laser coronary angioplasty (SELCA) and conventional excimer laser angioplasty: Comparison of vascular injury and smooth muscle cell proliferation.

Although the excimer laser, which utilizes 'non-thermal ablation effects', has achieved encouraging results in early clinical trials, the long-term results have failed to show any advantage over conventional percutaneous transluminal coronary angioplasty (PTCA).A new system, Smooth Excimer Laser Coronary Angioplasty (SELCA), has been developed to reduce the tissue damage in the vessel wall caused by shock waves and vapour bubbles.SELCA (wavelength 308 nm, pulse duration 115 ns, repetition rate 150 Hz and energy density 50 mJ mm(-2)) lowers the amount of shock wave formation and pressure peak amplitude in the surrounding tissue by about eight times when compared to the conventional 308 nm excimer laser (ELCA). In this preclinical evaluation, this new system was compared to ELCA. Fifty New Zealand White rabbits were stimulated by repeated weak DC impulses for a period of 28 days in order to form an atherosclerotic plaque in the right carotid artery. The vessels were excised 3, 7,14 and 28 days after laser irradiation for immunohistochemical analysis.SELCA and ELCA laser treatment lead to a decrease in maximal intimal wall thickness 3 days after intervention (control: 177+/-4 microm; SELCA: 131+/-22microm; ELCA: 120 +/-33microm). In the period between 3 and 28 days, a moderate increase in intimal wall thickness was observed after SELCA treatment compared to a significant increase after ELCA (28 days after intervention: SELCA: 157+/-22microm; ELCA: 274 +/-28microm). Bromodeoxyuridine (BrdU) was applied 18 and 12 h before excision of the vessels in order to determine the percent of cells undergoing DNA synthesis. The percent of BrdU labelled SMC in the intima (control: 13 +/- 2 cells mm(-2)) increased in both groups after 3 days (SELCA: 248 +/- 107 cells mm(-2); ELCA: 162 +/- 41 cells mm(-2)) and 7 days (SELCA: 162+/- 55 cells mm(-2); ELCA: 279 +/- 119 cells mm(-2)).The present results demonstrate that vascular wall injury and increase in intimal wall thickness following SELCA are reduced in comparison to the results achieved with the conventional technique. Further trials are necessary to assess whether these improvements will lead to more favourable long-term results after excimer laser angioplasty.

In vitro evaluation of ablation parameters of normal and fibrous aorta using smooth excimer laser coronary angioplasty.

A modified excimer laser energy delivery system was used to irradiate 100 segments of normal and fibrous aorta in vitro. The laser beam was scanned into 8 fiber bundles consisting of 50 fibers each resulting in a reduction of the applied pulse energy. The total repetition rate was increased to 150 Hz in order to keep the repetition rate per fiber bundle close to 20 Hz and to minimize thermal injury. The results demonstrate that effective ablation (etch rate per 8 pulses > 2.0 microns) occurred at an energy fluency of 50 mJ/mm2 in both normal and fibrous aorta. Tissue damage (carbonization, tissue separation, fissures, cracks, and vacuolization) was in a range of 100 +/- 28 to 152 +/- 30 microns for normal aorta and in a range of 57 +/- 35 to 110 +/- 39 microns for fibrous aorta. We conclude that effective ablation of normal and fibrous human aorta can be achieved by the application of smooth excimer laser coronary angioplasty. This improvement of excimer laser technology may result in a reduction of shock wave- and cavitation-induced damage leading to a reduction of tissue injury. However, this awaits further in vitro and in vivo confirmation.

Studies of the genotoxicity of glycidyl methacrylate (GMA).

The following experiments were conducted to evaluate the genotoxic effects of GMA (glycidyl methacrylate) on mammalian and human cells. (1) Using the absorption spectrum shift method in vitro, we observed that the maximums of calf thymus DNA and GMA were shifted toward longer wavelengths (a change of more than 15 nm) and the absorbance decreased after incubation at room temperature for 15 min or more. The result indicates that binding of DNA and GMA had occurred. The binding force is strong, not affected by the addition of concentrated sodium chloride solution, and only slightly decreased by the addition of 8 M urea solution. Therefore the bond between DNA and GMA might be covalent. (2) In cell cultures, unscheduled DNA synthesis (UDS) in human and/or rat lymphocyte was induced and DNA semiconservative replication was inhibited by GMA at concentrations of less than 5.2 mM. (3) Sperm abnormality tests and assays of UDS in germ cells of male mice were conducted to study the in vivo genotoxicity of GMA. The results revealed that GMA could damage DNA, increase sperm abnormality frequency, and reduce the number of sperm cells.

Analysis of the phenotype and the restriction enzyme mapping level of mutations induced by the new mutagen glycidyl methacrylate.

Glycidyl methacrylate (GMA) is a recently recognized chemical mutagen. In order to explore the mutagenicity and mutagenic process of GMA, plasmid pBR322 was used for in vitro binding, mutant screening, and restriction enzyme mapping. The binding between GMA and DNA in vitro has been verified by means of a spectrophotometric method. When pBR322 and GMA-bound pBR322 were used to transform Escherichia coli HB101, the following results were obtained: (1) The transformation efficiency of GMA-bound pBR322 was much lower than that of pBR322 alone. (2) GMA-bound pBR322 induced phenotype changes in competent cells (i.e., tetracycline-resistance inactivation or ampicillin-resistance inactivation). There were two mutants of pBR322, ApRTCS and ApSTcR, in the transformants and a deductive mutant ApsTcs in the nontransformants. (3) All of the selected mutants were stable and heritable. (4) When restriction enzyme maps were used to analyze the mutant ApRTcS, four of seven maps were changed, some sites were shifted to other resistant gene regions, for example, sites of Bg/I, EcoRI, HindIII, HincII, etc., and there was a new recognition site for HincII (252). We did not observe any DNA fragment insertion or deletion on any maps. Our results suggest that when GMA is covalently linked to the plasmid DNA, it gives rise to a premutagenic lesion of DNA that is converted in vivo into a point mutation.

Effects of pulse excimer laser irradiation on the human left ventricular wall.

This study was to assess the potential application of excimer lasers in the ablation of myocardium in vitro for the treatment of constant ventricular tachycardia or hypertrophic cardiomyopathy. A fresh human heart and EMG model 103 XeCl pulse excimer laser machine were used. The pulse repetition rate varied from 1 to 7 Hz. Irradiation directly on the left endocardial and epicardial walls lasted for 10 seconds and was repeated 3 times, creating 3 craters. The histological changes were examined by light microscope. Results showed very close relations between the depth or volume of vaporized craters and the pulse repetition rate on the endocardial (r = 0.9674, P less than 0.001 and r = 0.8962, P less than 0.01, respectively) and epicardial walls (r = 0.9602, P less than 0.001 and r = 0.9612, P less than 0.001, respectively). A sharp, clear border without debris or coagulating necrosis was seen under the microscope. We concluded that the pulse excimer laser, differing from Ar+ or Nd:YAG lasers, might be a powerful tool for manipulating the human ventricular wall, but more work needs to be done before it can be widely applied in the treatment of cardiovascular disease.