虾青素对成骨细胞羟自由基氧化损伤的影响

目的：在H2O2胁迫下，研究虾青素增强成骨细胞抗自由基损伤的作用。方法：用H2O2作用MC3T3-E1成骨细胞，建立自由基损伤细胞模型。培养的成骨细胞分为对照组、模型组、虾青素低剂量组（1×10^-7mol／L）、虾青素中剂量组（1×10^-6mol／L）和虾青素高剂量组（1×10^-5mol／L）。测定不同处理组细胞活力、超氧化物歧化酶（superoxide dismutase，SOD）活性、活性自由氧（reactive oxygen species，ROS）含量、脂质过氧化物（lipid oxygen，IJP0）含量，同时利用荧光偏振法测定细胞膜流动性。结果：模型组细胞活力、SOD活性、细胞膜流动性均比各剂量虾青素组显著降低（P〈0．01），而ROS、LPO含量均比各剂量虾青素组显著升高（P〈0．01）。结论：H2O2摄入会导致大鼠成骨细胞的氧化损伤，而虾青素可以预防或降低此类损伤对细胞的影响。     

Esophageal incisions repair by CO2 laser soldering

PURPOSE: This study evaluated the feasibility of fiberoptic CO2 laser soldering for the repair of esophageal injuries under tight temperature feedback control in an animal model. Healing was compared to conventional suture closure. MATERIALS AND METHODS: A CO2 soldering system equipped with infrared transmitting silver halide fibers was used. The soldered tissue temperature was monitored continuously, and laser power was adjusted to provide constant temperature. The procedure was done with 50% bovine serum albumin solder. Longitudinal incisions measuring 8 to 10 mm were made under general anesthesia in the cervical esophagus of 25 rats. Twenty rats (group I) underwent laser tissue bonding; 8 of which were tested in a preliminary study to determine optimal laser parameters. In the remaining 5 rats (group II, controls), closure was performed with 1 layer of 6/0 Vicryl sutures. The rats were sacrificed 2, 3, 4, and 6 weeks postoperatively, and the esophagus was examined histologically. RESULTS: Optimal temperature was found to be 65 to 70 degrees C and optimal exposure time, 150 to 200 seconds. Laser soldering was successful in 9 of the 12 rats (75%) treated under optimal settings; suturing was successful in 4 of the 5 control rats (80%). There were no significant differences between the groups in healing or complication rates. CONCLUSIONS: These results indicate that the CO2 laser soldering technique is a valid option for the correction of esophageal tears or incisions in rats. The confirmation and extension of these findings in further studies with larger animals may ultimately lead to the routine in vivo use of temperature-controlled laser repair for the esophagus and other organs. This method lends itself to endoscopic bonding of tissues.     

Brain tissue PO2, PCO2, and pH during cerebral vasospasm

BACKGROUND

The purpose of the present study was to assess brain tissue monitoring for detection of ischemia due to vasospasm in aneurysmal subarachnoid hemorrhage (SAH) patients.

METHODS

After obtaining informed consent, a burr hole was made in 10 patients and a Neurotrend 7 probe was inserted ipsilateral to the region of SAH. In eight patients the probe was inserted during surgery for clipping the aneurysm and in two patients the probe was inserted in the neurosurgery ICU. Brain tissue gases and pH were collected over 6-hour periods for 7 to 10 days until the termination of monitoring. The onset of vasospasm was confirmed by angiography and xenon computed tomography (Xe/CT) cerebral blood flow studies.

RESULTS

Seven patients did not develop vasospasm during monitoring and were considered as controls. In this group, brain tissue oxygen pressure (PO₂) remained above 20 mmHg, carbon dioxide pressure (PCO₂) stabilized at 40 mmHg and pH remained between 7.1 and 7.2. In three patients who developed vasospasm during monitoring, PO₂ was not different from the control group. However, PCO₂ increased to 60 mmHg and pH decreased to 6.7 (p < 0.001).

CONCLUSION

In this study, patients with SAH who developed vasospasm had significantly lower brain tissue pH and higher PCO₂ compared to controls. However, there was no significant change in PO₂ levels associated with vasospasm. Brain tissue monitoring can provide an indication of ischemia during vasospasm.     

兔肝缺血—再灌注时PtiO2,PtiCO2和pHti变化的研究

目的研究兔肝缺血-再灌过程中肝组织氧分压(PtiO     

Fiberoptic-guided CO2 laser for harvesting of the internal mammary artery

Objective: The internal mammary artery is the preferred conduit in coronary artery bypass grafting. Although most centers use electrocautery to dissect the internal mammary artery, it has several disadvantages. The purpose of this study in a canine model was to evaluate and compare a fiberoptic CO₂ laser device versus electrocautery for harvesting the internal mammary artery. Material and methods: In ten mongrel dogs, both internal mammary arteries with their surrounding pedicles, were dissected from the thoracic wall, using a low-current electrocautery for one artery and a continuous wave, fiberoptic-guided CO₂ laser (13 watts) for the contralateral vessel. Blood flow through the vessels was measured immediately after dissection. Results: Mean flow through the laser dissected arteries was 71.3±23.7 ml/min versus 52.9±16.5 ml/min in those dissected using electrocautery. Histological examination of the chest wall specimens dissected with electrocautery showed the presence of necrosis, edema and hemorrhage surrounding the muscle, while the specimens dissected with the laser revealed only a narrow area of burn on the surgical margins of the muscle. The laser-assisted dissection was more accurate, as easy, and almost as fast as with the use of electrocautery. Conclusions: Stripping of the internal mammary artery with the fiberoptic CO₂ laser offers a promising alternative to electrocautery. Owing to its greater accuracy, the laser technique may reduce the likelihood of damaging the endothelial lining of the dissected vessel. By reducing the degree of soft tissue damage, the CO₂ laser may also lower the incidence of sternal wound infection and reduce postoperative chest wall pain and dysesthesia.     

Thermal damage produced by high-irradiance continuous wave CO2 laser cutting of tissue

Thermal damage produced by continuous wave (cw) CO2 laser ablation of tissue in vitro was measured for irradiances ranging from 360 W/cm2 to 740 kW/cm2 in order to investigate the extent to which ablative cooling can limit tissue damage. Damage zones thinner than 100 microns were readily produced using single pulses to cut guinea pig skin as well as bovine cornea, aorta, and myocardium. Multiple pulses can lead to increased damage. However, a systematic decrease in damage with irradiance, predicted theoretically by an evaporation model of ablation, was not observed. The damage-zone thickness was approximately constant around the periphery of the cut, consistent with the existence of a liquid layer which stores heat and leads to tissue damage, and with a model of damage and ablation recently proposed by Zweig et al.     

Comparative study of low power neodymium-YAG laser interstitial hyperthermia versus ethanol injection for controlled hepatic tissue destruction

A solitary hepatic metastasis is amenable to surgery. However, if surgery is contraindicated or if multiple lesions are present in both liver lobes, other treatment modalities have to be considered. We compared the effect of interstitial laser hyperthermia with damage caused by alcoholization. Six anaesthetized beagle dogs were studied. Three animals were treated with laser hyperthermia. A bare laser fibre (400m diameter) was introduced through a 17-gauge needle, length 170 mm, positioned into the liver under real time ultrasonographic guidance. Lesions were produced by continuous 500-s exposure of 1W YAG laser (Medilas MBB 40N) power. Three dogs were subjected to an injection of 4 ml of 98% pure ethanol into the liver through the same needle system. Two days after the procedure the animals were killed and the livers examined. The surface of the livers treated with the YAG laser were entirely normal; superficial lesions were, however, clearly visible. Laserinduced lesions were well reproducible, clearly demarcated, roughly spherical with a mean diameter of 1.01±0.23 cm (n=16). In contrast, the dogs treated with alcohol had free intraperitoneal serohaemorrhagic fluid and the surface of the liver was diffusely abnormal. The lesions had a more or less cylindrical shape, 1.22±0.43 cm on 0.40±0.10 cm (n=12) although exact measurement was often difficult. The border of the lesions was irregular and there was a clear necrotic zone along the puncture track. On microscopic examination the laser-induced lesions consisted of a central evaporation area, a zone of carbonized material and an outer zone of coagulation necrosis. The alcohol-induced lesions were characterized by both fixation necrosis and coagulative necrosis but surprisingly, there was also necrosis present at a distance of the lesions extending along the centrilobular and even portal veins. These data show that laser-induced interstitial necrosis in the liver is better controlled and more reproducible than necrosis induced by injection of pure ethanol. Moreover, pure ethanol may cause damage to the liver surface and even at a distance of the injection site.     

Prostaglandin E2 receptor subtype 3-siRNA reduces the mesangial cell damage induced by TGF-β1through inhibiting MAPK pathway in mice

Objective To investigate the effects and mechanisms of prostaglandin E2 receptor subtype 3 (EP3) on transforming growth factor β1 (TGF-β1)-induced mouse mesangial cells damage. Methods Primary mouse mesangial cells were separated and cultured. Three siRNAs were synthesized and transfected into mesangial cells for silencing EP3 by LipofectamineTM 2000 and the best one was chosen. MCs were grouped into: (1)control group; (2)TGF-β1 (10 μg/L) group; (3)NC-siRNA plus TGF-β1 (10 μg/L) group; (4) EP3-siRNA group; (5)EP3-siRNA plus TGF-β1 (10 μg/L). Then the proliferation of MCs was evaluated by CCK-8 assay. The expression of PGE2 and cAMP in cell supernatant were detected by ELISA. The mRNA and protein expression of fibronectin (FN), connective tissue growth factor (CTGF), cyclooxygenase-2 (COX2), membrane-bound prostaglandin E2 synthase 1 (mPGES1) were detected by real-time quantitative PCR and Western blotting. The phosphorylation of p38 MAPK and ERK1/2 was decected by Western blotting. Results Compared with control group, the cell proliferation induced by TGF-β1 was increased (P＜0.05), the expression of PGE2 and cAMP were improved, mRNA and protein expression of FN, CTGF, COX2 and mPGES1 were up-regulated (all P＜0.05). Compared with TGF-β1 group, the cell proliferation in EP3-siRNA plus TGF-β1 group was reduced, the expression of FN, CTGF, COX2 and mPGES1 mRNA and protein were downregulated (all P＜0.05), the phosphorylation of ERK1/2, p38 MAPK were also declined (P＜0.05). Conclusion EP3-siRNA may reduce TGF-β1-induced cell damage through upregulating the expression of cAMP, repressing the activity of ERK1/2 and p38 MAPK, inhibiting the expression of COX2 mPGES1 and PGE2 by feedback, then decreased the expression of FN and CTGF.     

烧伤病人痂下水肿液对内皮细胞的损伤作用

目的了解痂下水肿液(Subeschar tissue fluid,STF)对内皮细胞的损伤作用,进一步论证 STF 是烧伤后一“贮毒库”的概念。方法取烧伤病人痂下水肿液,按20％比例与体外培养的人脐静脉内皮细胞(HUVEC)培养1,12,24h,测定培养液中乳酸脱氢酶(LDH)和6-keto-PGF 1α,观察内皮细胞活力和形态改变,并用健康人血清作对照。结果 STF 与 HUVEC 一同孵育后培养液中LDH 活性和6-keto-PGF 1α含量逐渐升高,并明显高于健康人血清对照组(P<0.01),且 STF 与 HU-VEC 共同孵育24h,内皮细胞活力下降,内皮细胞出现收缩,细胞间间隙增大,部分细胞脱落和坏死,而健康人血清未能引起内皮细胞功能和形态改变。结论 STF 可损伤内皮细胞,在烧伤后内皮细胞的损伤中起重要作用。     

烧伤病人痂下水肿液对内皮细胞的损伤作用

目的　了解痂下水肿液（ Ｓｕｂｅｓｃｈａｒ ｔｉｓｓｕｅ ｆｌｕｉｄ , Ｓ Ｔ Ｆ） 对内皮细胞的损伤作用,进一步论证 Ｓ Ｔ Ｆ 是烧伤后一“贮毒库”的概念。方法　取烧伤病人痂下水肿液,按２０ ％ 比例与体外培养的人脐静脉内皮细胞（ Ｈ Ｕ Ｖ Ｅ Ｃ） 培养１ ,１２ ,２４ｈ ,测定培养液中乳酸脱氢酶（ Ｌ Ｄ Ｈ） 和６ｋｅｔｏ Ｐ Ｇ Ｆ１α,观察内皮细胞活力和形态改变,并用健康人血清作对照。结果　 Ｓ Ｔ Ｆ 与 Ｈ Ｕ Ｖ Ｅ Ｃ 一同孵育后培养液中 Ｌ Ｄ Ｈ 活性和６ｋｅｔｏ Ｐ Ｇ Ｆ１α含量逐渐升高,并明显高于健康人血清对照组（ Ｐ＜ ００１） ,且 Ｓ Ｔ Ｆ 与 Ｈ Ｕ Ｖ Ｅ Ｃ 共同孵育２４ｈ ,内皮细胞活力下降,内皮细胞出现收缩,细胞间间隙增大,部分细胞脱落和坏死,而健康人血清未能引起内皮细胞功能和形态改变。结论　 Ｓ Ｔ Ｆ 可损伤内皮细胞,在烧伤后内皮细胞的损伤中起重要作用。     

Comparative study of Nd-YAG laser versus electrocautery for liver metastatic resection in the rat

The thermal, hemostatic and lymphostatic effects of the Nd-YAG laser suggest a benefit in the treatment of multiple liver metastases. The aim of this work was to evaluate experimentally this hypothesis in a comparative study with conventional electrocautery resection of liver metastases. The original animal model was represented by syngeneic BDIX rats inoculated under the liver capsule with 1.5×10⁶ DHD/K12 tumour cells originating from a clone of a 1,2 dimethyl hydrazine induced rat colon cancer. One hundred and ten rats bearing three liver metastases were randomly treated by laser volatilization or electrocautery enucleation. The first group of 60 rats was used as a survival group: the laser treated rats survived significantly longer than rats treated by cautery (49.9 days vs 28.9 days) (mean values;p<0.015). In this group, the temperature elevation during operation at the edge of the treated lesion was found higher in the laser group than in the cautery group (56±4.6°C vs 8±3°C) (mean values±s.d.;p<0.001). Nd-YAG laser was also a faster procedure than cautery resection (21±4.2 s vs 57±6.1 s) (mean values±s.d.;p<0.001). At the time of autopsy, the infection rate with laser was found lower than in the cautery group (p<0.025) while no bile leakage was evident. A peritoneal tumour dissemination with ascites was noted in the majority of dead rats. In the second group of 50 rats, the metastatic recurrence was assessed. At day 7, no metastases were found in the laser treated rats while a mean number of 6.5 was found in the cautery group (p<0.001). At the 15th day, more metastases were present in the cautery group. There was a significant correlation between the total number of metastases and the time of death. Those findings suggest that the Nd-YAG laser destruction of experimental liver metastases by its specific effects on tumour cells delayed the recurrence of metastases when compared to the electrocautery resection, contributing to a longer survival of the laser treated rats.     

Histopathological features of liver damage induced by laser ablation in rabbits

BACKGROUND AND OBJECTIVE: Possible mechanisms that promote or interfere with the effects of laser ablation of the liver have not been clarified. The aim of this study was to define the chronological alterations in the normal rabbit liver at early stages after laser ablation. STUDY DESIGN/MATERIALS AND METHODS: Rabbit livers were ablated with a laser via an optical fiber and then analyzed histopathologically by immunostaining for heat shock protein 70 (HSP70) and by the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling (TUNEL) method. RESULTS: The lesions increased in size progressively over the 24 h that followed ablation and the area of the lesion coincided with the area that had been heated above 43 degrees C. TUNEL-positive hepatocytes were surrounded, at some distance, by HSP70-positive hepatocytes were surrounded, at some distance, by HSP70-positive hepatocytes at 6 h, and such cells were in contact with each other at 24 h. CONCLUSIONS: Injury to hepatocytes induced by laser ablation increases for 24 h and dying cells express nuclear HSP70, with subsequent fragmentation of DNA.