First Report of Powdery Mildew of Hexinia polydichotoma Caused by Leveillula lactucae-serriolae in China

Hexinia polydichotoma (Ostenf) H.L. Yang (synonym Chondrilla polydichotoma Ostenf.) is an indigenous sand-binding plant that is widely distributed only in the desert regions of Northwest China. During the summer of 2007, severe outbreaks of a previously unknown powdery mildew were observed in the Taklimakan Desert in Xinjiang, China. Almost 95% of the plants surveyed were affected in this area. The upper surfaces of the stem were covered with white mycelia and the corresponding abaxial surfaces of infected leaves were chlorotic. Affected young, green stems also showed extended chlorosis. As the disease progressed, the infected stems turned yellow and necrotic. Heavy infection resulted in death of the plants. The primary conidia of the fungus were lanceolate with apical pointed, rarely cylindrical or subcylindrical with attenuated apex. They measured 53 to 73 × 15 to 21 μm and had a surface with a net of irregular rides and warts. Subcylindrical or subclavate secondary conidia with rounded ends measuring 50 to 77 × 13 to 20 μm were observed. The ascomata are subgregarious to scattered, globose, and 165 to 200 μm in diameter that are immersed in the dense mycelial tomentum. Numerous and well-developed appendages on the lower half of the ascomata are irregularly branched and can be as long as up to the ascomata diameter. The appendages measure 79 to 106 × 5 to 10 μm and are aseptate, thin walled, and smooth. Asci are numerous (usually more than 20 per ascoma), stalked, clavate-ovoid to nearly cylindrical, and contain two spores (rarely one or three). Ascospores are ellipsoid, hyaline, and measure 25 to 35 × 14 to 20 μm. On the basis of these characteristics, the fungus was identified as Leveillula lactucae-serriolae (2). A voucher specimen was deposited in the Herbarium of Martin Luther University, Halle, Germany (Accession No. HAL 2439F). To confirm the identification, the internal transcribed spacer (ITS) rDNA was amplified and sequenced, and deposited in GenBank (Accession No. HQ821500). Comparison with sequences available in the GenBank database revealed that the ITS sequence shares 99% similarity with that of L. lactucaeserriolae on Lactuca serriola from Iran (Accession No. AB044375.1) (1). Thus, the pathogen was identified as L. lactucae-serriolae based on the host plant species, anamorph morphology, and ITS sequence. Pathogenicity was confirmed through inoculation by gently pressing a diseased stem onto the stem of healthy H. polydichotoma plants. Five inoculated plants were kept under a plastic humid chamber, whereas the same number of noninoculated plants served as the control. The plants were placed under natural conditions (25 to 28°C) with 80 to 90% humidity. At 15 days after inoculation, typical symptoms of powdery mildew developed on the inoculated plants. No symptoms were seen on the control plants. To our knowledge, this is the first report of L. lactucaeserriolae in China and the first record of L. lactucae-serriolae on H. polydichotoma in the world ( http://nt.ars-grin.gov/fungaldatabases/index.cfm ). Because the plant is becoming widely cultivated in the Taklimakan Desert for use in sand-binding, the powdery mildew poses a serious threat to desertification control. References: (1) S. A. Khodaparast et al. Mycol Res. 105:909. 2001. (2) S. A. Khodaparast et al. Mycoscience 43:459, 2002.

Effects of Auxiliary Fiber Posts on Endodontically Treated Teeth With Flared Canals

Macro-Lock post combined with auxiliary fiber posts could increase the fracture resistance of endodontically treated roots with over-flared canals. However, an effect of the auxiliary fibers on retention strength was not observed.

First Report of Pomegranate Wilt Caused by Ceratocystis fimbriata in Sichuan Province

During May of 2009, a new devastating disease was observed on pomegranate (Punica granatum L.) that caused losses estimated at 30% as surveyed by 10 orchards in Panzhihua-Xichang Region of Sichuan Province, Southwest China. Characteristic symptoms were yellow and wilting leaves. Initial symptoms only occurred on shoots, but later, leaves of the whole tree turned yellow and wilted, causing extensive defoliation and dieback and the xylem of the trunk turned brown to black with a star burst-like pattern. Finally, heavy infection resulted in the whole tree dying, causing severe yield losses. A fungus was consistently isolated from basal stems and roots of diseased plants. Single conidia were obtained and cultured on potato dextrose agar (PDA) and incubated at 25 ± 1°C with a 12-h light/dark photoperiod. Mycelium was initially hyaline and then rapidly became dark greenish brown. Two types of endoconidia were produced in 5 days. Barrel-shaped conidia were hyaline, 1-celled, and measured 7.3 to 9.4 × 11.6 to 13.2 μm. Cylindrical conidia were hyaline, 1-celled, and measured 9.2 to 29.6 × 3.1 to 6.8 μm. Aleurioconidia were brownish, thick walled, near globose, and measured 8.7 to 18.1 × 8.2 to 10.7 μm. Perithecia were dark brown to black, globose, measured 90.8 to 149.8 μm in diameter, and had a long thin neck, 254.4 to 533.8 μm long, through which ascospores exuded. Ascospores were small, hyaline, hat shaped, measured 3.7 to 6.5 × 3.1 to 5.7 μm, and accumulated in a sticky matrix at the tip of the ascomal neck. The fungus was identified as Ceratocystis fimbriata (anamorph Chalara sp.) (1). The internal transcribed spacer (ITS) region of rDNA was amplified with universal primers ITS4/ITS5 and sequenced (GenBank Accession No. HQ529711), and comparisons with GenBank showed 99% similarity with C. fimbriata on Colocasia esculenta from Brazil (Accession No. AM712448.1). Pathogenicity tests were conducted. Two-week-old seedlings of pomegranate cv. Qingpiruanzi, germinated in plastic containers in the greenhouse, were wounded with a needle to a depth of 0.5 mm at the base of the stem below the soil level and near the root system, and then inoculated by drenching the wounds with a spore suspension (10⁵ conidia per ml). Control plants were inoculated with sterile water. There were four replicates for each treatment. The treated plants were incubated at 25 ± 1°C with 80 to 95% relative humidity under a 12-h light/dark photoperiod in a greenhouse. All inoculated plants wilted within 25 days after inoculation and C. fimbriata was reisolated. All control plants remained healthily. To our knowledge, this is the first finding of pomegranate wilt caused by C. fimbriata in Sichuan Province. This pathogen may pose a serious threat to pomegranate production in Sichuan where it is a major fruit tree. This pathogen has been previously reported in India (3) and Yunnan Province, China (2), but is not known elsewhere. References: (1) C. J. B. Engelbrecht and T. C. Harrington. Mycologia 97:57, 2005. (2) Q. Huang et al. Plant Dis. 87:1150, 2003. (3) Y. M. Somasekhara. Plant Dis. 83:400, 1999.

Experience with adrenal schwannoma in a Chinese population of six patients

OBJECTIVES

Benign adrenal schwannoma is an extremely uncommon cause of incidentaloma. This article describes our experience with the diagnosis and treatment of adrenal schwannoma in a Chinese population of 6 patients. To our knowledge, this is the largest series of this uncommon adrenal tumor treated in a single center.

METHODS

From May 1999 to May 2009, 6 patients with incidentally discovered adrenal schwannoma were operated on at a tertiary referral hospital in Eastern China. Clinical details, radiographic features, laboratory examinations, pathological findings, and follow-up data of these patients were analyzed.

RESULTS

Of the 6 patients, 4 were females (F) and 2 were males (M), with a mean age of 40.5 yr (range: 30-47, M:F=2:1). The 6 patients were managed with open unilateral adrenalectomy; 5 patients had schwannomas on the left side, and 1 on right side. Abnormal urine catecholamine was detected in 1 patient. The mean pathological size of these tumors was 4.3 ± 1.1 cm. The diagnosis of schwannoma was based on classic histological findings, and supported by immunohistochemistry of S-100, vimentin, and ABC positivity. In the follow- up of 47.5 ± 32.3 months, no recurrence and metastasis were observed.

CONCLUSIONS

Although there may be some clues for radiological diagnosis of adrenal schwannoma, preoperative misdiagnosis is not infrequent. Those tumors may occasionally have endocrine function. Histological examination is the key of diagnosis, and surgical resection is the treatment of choice once malignancy cannot be excluded by preoperative analyses.

Molecular cloning and characterization of a thioredoxin peroxidase gene from Apis cerana cerana

Thioredoxin peroxidases (Tpxs) play important roles in protecting organisms against the toxicity of reactive oxygen species (ROS) and regulating intracellular signal transduction. In the present study, we cloned the full cDNA of Tpx1 encoding a 195-amino acid protein from Apis cerana cerana (Acc). Based on the genomic DNA sequence, a 1442-bp 5'-flanking region was obtained, and the putative transcription factor binding sites were predicted. Quantitative PCR analysis showed that AccTpx1 was highly expressed in thorax and that the AccTpx1 transcript reached its highest level in two-week-old adult worker honeybees. Moreover, expression of the AccTpx1 transcript was increased by various abiotic stresses, such as ultraviolet light, HgCl(2) , and insecticide treatments. In addition, the recombinant AccTpx1 protein exhibited antioxidant activity; it removed hydrogen peroxide and protected DNA. These results suggest that AccTpx1 plays an important role in protecting honeybees from oxidative injury and may act in extending the lifespan of them.

Disulfiram modulated ROS-MAPK and NFκB pathways and targeted breast cancer cells with cancer stem cell-like properties

Background:

Previous studies indicate that disulfiram (DS), an anti-alcoholism drug, is cytotoxic to cancer cell lines and reverses anticancer drug resistance. Cancer stem cells (CSCs) are the major cause of chemoresistance leading to the failure of cancer chemotherapy. This study intended to examine the effect of DS on breast cancer stem cells (BCSCs).

Methods:

The effect of DS on BC cell lines and BCSCs was determined by MTT, western blot, CSCs culture and CSCs marker analysis.

Results:

Disulfiram was highly toxic to BC cell lines in vitro in a copper (Cu)-dependent manner. In Cu-containing medium (1 μM), the IC₅₀ concentrations of DS in BC cell lines were 200–500 nM. Disulfiram/copper significantly enhanced (3.7–15.5-fold) cytotoxicity of paclitaxel (PAC). Combination index isobologram analysis demonstrated a synergistic effect between DS/Cu and PAC. The increased Bax and Bcl2 protein expression ratio indicated that intrinsic apoptotic pathway may be involved in DS/Cu-induced apoptosis. Clonogenic assay showed DS/Cu-inhibited clonogenicity of BC cells. Mammosphere formation and the ALDH1^+VE and CD24^Low/CD44^High CSCs population in mammospheres were significantly inhibited by exposure to DS/Cu for 24 h. Disulfiram/copper induced reactive oxygen species (ROS) generation and activated its downstream apoptosis-related cJun N-terminal kinase and p38 MAPK pathways. Meanwhile, the constitutive NFκB activity in BC cell lines was inhibited by DS/Cu.

Conclusion:

Disulfiram/copper inhibited BCSCs and enhanced cytotoxicity of PAC in BC cell lines. This may be caused by simultaneous induction of ROS and inhibition of NFκB.

Cancer targeting Gene-Viro-Therapy of liver carcinoma by dual-regulated oncolytic adenovirus armed with TRAIL gene

Liver cancer is a common and aggressive malignancy, but available treatment approaches remain suboptimal. Cancer targeting Gene-Viro-Therapy (CTGVT) has shown excellent anti-tumor effects in a preclinical study. CTGVT takes advantage of both gene therapy and virotherapy by incorporating an anti-tumor gene into an oncolytic virus vector. Potent anti-tumor activity is achieved by virus replication and exogenous expression of the anti-tumor gene. A dual-regulated oncolytic adenoviral vector designated Ad·AFP·E1A·E1B (Δ55) (Ad·AFP·D55 for short thereafter) was constructed by replacing the native viral E1A promoter with the simian virus 40 enhancer/α-fetoprotein (AFP) composite promoter (AFPep) based on an E1B-55K-deleted construct, ZD55. Ad·AFP·D55 showed specific replication and cytotoxicity in AFP-positive hepatoma cells. It also showed enhanced safety in normal cells when compared with the mono-regulated vector ZD55. To improve the anti-hepatoma activities of the virus, the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) gene was introduced into Ad·AFP·D55. Ad·AFP·D55-TRAIL exhibited remarkable anti-tumor activities in vitro and in vivo. Treatment with Ad·AFP·D55-TRAIL can induce both autophagy owing to the Ad·AFP·D55 vector and caspase-dependent apoptosis owing to the TRAIL protein. Therefore, Ad·AFP·D55-TRAIL could be a potential anti-hepatoma agent with anti-tumor activities due to AFP-specific replication and TRAIL-induced apoptosis.

IL-10 polymorphisms and prostate cancer risk: a meta-analysis

Evidence is accumulating that chronic inflammation may have an important role in prostate cancer (PCa). Three common polymorphisms in the promoter of interleukin-10 (IL-10) gene, -1082 A>G, -819 C>T and -592 C>A, have been implicated to alter the risk of PCa, but the results of relative studies are inconclusive or controversial. To derive a more precise estimation of the relationship, we performed an updated meta-analysis on the basis of 10 studies. A comprehensive search was conducted to examine all the eligible studies of IL-10 polymorphism and PCa risk. We used odds ratios (ORs) to assess the strength of the association, and 95% confidence intervals (CIs) give a sense of the precision of the estimate. Overall, there were no significant associations between increased risk of PCa and IL-10 -1082 A>G, -819 C>T and -592 C>A polymorphisms. However, meta-analysis suggested that IL-10 -819 C>T and -592 C>A polymorphisms might be modestly associated with PCa aggressiveness (T versus C, OR=1.162, 95% CI: 1.035-1.305, P=0.011; A versus C, OR=1.131, 95% CI: 1.012-1.264, P=0.030; respectively). IL-10 -819 C>T and -592 C>A polymorphisms might impact PCa progression. Variant alleles at both -819 and -592 were modestly associated with advanced stages of PCa. Additional well-designed studies are warranted to validate these findings.

The Effects of Film Thickness and Texture on the high and Low-Field stress Response of Lead Zirconate Titanate Thin Films

Lead zirconate titanate (PZT) thin films are currently employed in non-volatile ferroelectric memories (FRAM's) and are intended to be used as the active material in a number of microelectromechanical systems (MEMS). Several groups have reported that both the piezoelectric and dielectric characteristics of ferroelectric thin films improve with an increase of film thickness, though the reasons for those improvements are unclear. Previous investigations on the effects of biaxial mechanical stress indicate that non-180° domain wall motion is limited in PZT 52/48 films less than 0.5 μm thick. It is possible that some of the improvements of the dielectric and piezoelectric characteristics reported for thicker films (i.e. films thicker than 0.5 μm) are associated with an increase of extrinsic contributions to the properties. To evaluate domain wall mobility in thicker films, the high and low-field stress response of sol-gel PZT fabricated with either rapid thermal processing or conventional furnace annealing were investigated. Films with thicknesses ranging from 0.6 to 5.0 μm thick were measured as a function of applied biaxial stress (±110 MPa). It was found that for all films tested the changes of capacitance were on the order of 2–3%. High-field measurements showed: (1) the coercive field to be insensitive to applied stress, (2) remanent polarizations to decrease about 20% at the maximum applied tension, (3) remanent polarizations to increase less than 10% with applied compression, and (4) all changes to be reversible over the stress range investigated. These results suggest that extrinsic contributions are limited for the films tested.

The fungicide ciclopirox inhibits lymphatic endothelial cell tube formation by suppressing VEGFR-3-mediated ERK signaling pathway

Ciclopirox olamine (CPX), an off-patent antifungal agent used to treat mycoses of skin and nails, has recently been demonstrated to be a potential anticancer agent. However, the underlying mechanism is not well understood. Here for the first time we show that CPX inhibited lymphangiogenesis in an in vitro model (tube formation). This effect was in part associated with inhibition of vascular endothelial growth factor receptor 3 (VEGFR-3) expression, as overexpression of VEGFR-3 conferred partial resistance to CPX inhibitory effect on tube formation in lymphatic endothelial cells (LECs), whereas downregulation of VEGFR-3 mimicked the effect of CPX, blocking the tube formation. Further study revealed that CPX did not alter mRNA level, but inhibited protein synthesis and promoted protein degradation of VEGFR-3. In addition, we found that CPX inhibited phosphorylation of the extracellular signal-related kinase 1/2 (ERK1/2), a downstream effector of VEGFR-3. Overexpression of VEGFR-3 attenuated CPX inhibition of ERK1/2 phosphorylation, whereas downregulation of VEGFR-3 inhibited extracellular signal-related kinase 1/2 (ERK1/2) phosphorylation in LECs. Ectopic expression of constitutively active mitogen -activated protein kinase kinase 1 (MKK1) resulted in activation of ERK1/2, and partially prevented CPX inhibition of LEC tube formation. The results suggest that CPX inhibits LEC tube formation at least in part through inhibiting VEGFR-3-mediated ERK signaling pathway.

Abstract P2-09-21: Effect of MDR1 Gene Polymorphisms and Haplotypes on Taxanes-Based Chemotherapy Responses in Chinese Han Patients with Breast Cancer

Background: In recent years, taxanes play an important role in chemotherapy of breast cancer patients, and its response rate is about 50%. Taxanes is primarily metabolized by CYP450 in liver microsome, and it also is a substrate for P-glycoprotein (the coded product of MDR1 gene). The interindividual heterogeneity in drug-metabolizing enzymes and transporters has contributed to the variability on anti-cancer efficacy of taxanes in breast cancer patients. Several studies showed that the pharmacokinetics of taxanes was influenced by the MDR1 polymorphisms. The aim of this study is to investigate the relationship between MDR1 gene polymorphisms and taxanes-based chemotherapy responses, and provides useful information for clinical personalized medicine and prognostic judgment.

Material and Methods: Genotyping of MDR1 variants was determined in the blood samples from 142 Chinese Han patients with breast cancer, by PCR-RFLP. The association of the gene polymorphisms of MDR1 C1236T at exon 12, G2677T/A at exon 21 and C3435T at exon 26 with chemotherapy responses was analyzed on the 63 patients, who received taxanes-based neoadjuvant chemotherapy [56 cases with TA (taxanes and anthracycline), 7 cases with TAC (C: cyclophosphamide)] and had the intact treatment follow-up information.

Results: In the 142 breast cancer patients, the frequencies of C1236T, G2677T, G2677A and C3435T variant alleles was 70.7%,52.1%,2.5% and 46.5%, respectively, and the frequency of 3435T allele was significantly higher in comparison with that in healthy subjects (34.7%). In the 63 patients with neoadjuvant chemotherapy, the overall clinical response rate (CR+PR) to chemotherapy was 66.7%. 3435TT genotype was showed to be related to taxanes-based chemotherapy, and its efficient rate was 23.1%, significantly lower than that of patients carrying C allele (73.5%; x2 = 9.125, P=0.003). The 3 SNPs were in linkage disequilibrium, and the 4 haplotypes TTT, TGC, CGC and TTC were 90.6 % of all. The patients who carrying 2677G-3435C haplotype showed better response to chemotherapy compared with those with the other haplotypes combined (72.1% vs 40.0%;x2=9.125, P=0.003). The response rate of the patients with 2677T-3435T haplotype or 1236T-3435T haplotype (54.3% or 54.9%) were lower than that of the patients harboring the other haplotypes (82.4% or 91.7%;x2=4.128 and x2=4.118, P =0.042 for both) respectively, and the efficient rate of the patients with 1236T-2677T-3435T (54.3%) were also lower than that of the patients with other haplotypes combined (82.4%;x2=4.128, P=0.042).

Conclusion: C1236T, G2677T/A and C3435T of MDR1 gene were polymorphic with different frequency in breast cancer patients. The analyses of MDR1 C3435T genotype and its haplotypes with C1236T or G2677T/A are valuable for predicting the taxanes-based chemotherapy responses in breast cancer patients, which deserve the further study.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P2-09-21.

Abstract P6-11-02: Final Analysis of NO16853, a Randomized Phase II Non-Inferiority Study of Two Different Doses of Capecitabine in Combination with Docetaxel for Locally Advanced/Metastatic Breast Cancer (LA/MBC)

Background: In the phase III registration trial of capecitabine (X) plus docetaxel (T) in MBC (SO14999), a higher proportion of pts treated with XT vs T alone experienced grade 3/4 AEs (78% vs 64%, respectively), and dose reductions (65% vs 36%, respectively). Previously, it has been shown that dose reductions of X allow pts to continue therapy without compromising efficacy. Thus, this open-label, multicenter, phase II study was requested by the FDA, to investigate whether a lower dose of XT would be at least equivalent to standard-dose XT in LA/MBC.

Methods: Females aged ≥18 years with LA/MBC resistant to an anthracycline-based regimen in the (neo)adjuvant, 1st-or 2nd-line metastatic setting were eligible. Pts had ≥1 target lesion and ≥2 prior regimens in the metastatic setting. Following stratification (region; age; anthracycline status; prior taxane use), pts were randomized to 3-weekly cycles of standard XT (X 1,250mg/m2 b.i.d., d1-14 + T 75mg/m2, d1), or low-dose XT (X 825mg/m2 b.i.d., d1-14 + T 75mg/m2, d1) up to 16 cycles. Pts without PD entered a post-study treatment phase until PD or unacceptable toxicity. Primary endpoint: non-inferiority of low-dose vs standard XT in terms of PFS. Secondary endpoints: safety; ORR; duration of response; time to treatment failure; OS.

Results: Between 2003 and 2008, 470 pts, median age 51 years (range 22-75), were enrolled. Most pts (∼60%) received XT in the 1st-line setting. The primary analysis was based on the per-protocol population: standard XT (n=230), low-dose XT (n=229). Median PFS was 7.9 vs 6.0 months (HR 1.13, 95% CI: 0.93-1.37) in the standard and low-dose XT arms, respectively. As the upper limit of the 95% CI was above the predefined non-inferiority margin (1.35), the primary endpoint was not met. Secondary efficacy endpoints were consistent with PFS: median OS was 18.5 vs 15.2 months (HR 1.21, 95% CI: 0.96-1.52); ORR was 46.1% vs 38.4% (odds ratio 0.73, 95% CI: 0.50-1.06) with standard and low-dose XT, respectively. Median total dose intensity for X was 0.82 for standard dose and 0.91 for the lower dose. Exploratory analyses using established modelling and simulation methods show that 1,000mg/m2 X in combination with T would have demonstrated non-inferiority to standard XT with 80% power. The frequency of AEs was similar across the two groups: 94.9% standard XT (n=206) vs 94.4% low-dose XT (n=234), as was the incidence of serious AEs: 18.9% vs 21.4%, respectively. Differences were noted between the standard and low-dose XT group, respectively, in terms of the incidence of grade 3 hand-foot syndrome (16.1% vs 7.3%) and grade 3/4 neutropenia (32.7% vs 23.8%).

Conclusions: Non-inferiority of low-dose XT to standard XT was not demonstrated, yet superiority of the standard dose could not be established. Exploratory analyses suggest that X 1,000mg/m2 plus T would demonstrate non-inferiority to standard XT. Though not directly comparable, the efficacy of low-dose XT was similar to that of standard XT in study SO14999. A lower incidence of serious AEs was noted as compared with study SO14999 (43%) possibly reflecting improvements in dose modification, AE management and pt selection over time.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P6-11-02.

Downregulation of caspase-9 is a frequent event in patients with stage II colorectal cancer and correlates with poor clinical outcome

OBJECTIVE

 To evaluate the clinical significance of caspase-9 mRNA expression and investigate its prognostic value in stage II colorectal cancer.

METHOD

Quantitative real-time RT-PCR was used to analyse caspase-9 mRNA expression in cancer tissue and corresponding normal mucosa from 120 patients.

RESULTS

Compared with normal mucosa, the expression of caspase-9 mRNA was found to be downregulated in cancer tissue (P = 0.001). Poorly differentiated cancer showed lower mRNA expression than cancer with greater differentiation (P = 0.031). The Kaplan-Meier survival analysis demonstrated that patients with downregulated caspase-9 showed a worse overall survival (P = 0.012) and disease-free survival (P = 0.022). Cox's proportional hazards regression model confirmed that expression of caspase-9 was the strongest prognostic factor in stage II colorectal cancer.

CONCLUSION

The mRNA expression of caspase-9 can be used as an independent prognostic factor for patients with stage II colorectal cancer.

Effect of oxygenation of transperitoneal ventilation on the death time after asphyxiation in rabbits

BACKGROUND

To observe the effects of transperitoneal ventilation on death time in asphyxiated rabbits.

METHODS

Twenty-four adult rabbits were randomly divided in three groups (N=8, each): control group (no transperitoneal ventilation), air group (transperitoneal ventilation with air) and oxygen group (transperitoneal ventilation with oxygen). All animals were anesthetized with pentobarbital (3%, 30 mg/kg) given via intramuscular injection. Autonomous breathing was maintained. Each rabbit's peritoneal cavity was punctured with two catheters, one of which was placed in the left lower abdomen and served as the inlet for gas; the other was placed in the right upper abdomen and served as the outlet for gas. Asphyxia was induced by clamping the rabbit's trachea; transperitoneal ventilation was then administered in the air group and the oxygen group. Rabbits' death times were recorded and their heart rate, blood pressure, PaO2, and PaCO2 were monitored and analyzed before asphyxia and every minute after asphyxia.

RESULTS

All animals died successively after asphyxia. The death time in the oxygen group was significantly longer than in the control group and the air group, with no significant difference between the control group and the air group. PaO2 of all three groups declined significantly and the levels of PaO2 within 1-4 minutes after asphyxia in the oxygen group were higher than in the other two groups. PaCO2 increased significantly in all groups with no significant difference among three groups within 1-3 minutes after asphyxia. The increase of PaCO2 at the fourth minute in the oxygen group was reduced in comparison to that observed in other groups.

CONCLUSION

These results suggest that transperitoneal ventilation can markedly prolong the death time of asphyxiated rabbits.