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101.
Benzo[a]pyrene at an environmentally relevant dose is slowly absorbed by, and extensively metabolized in, tracheal epithelium 总被引:2,自引:0,他引:2
Gerde P; Muggenburg BA; Thornton-Manning JR; Lewis JL; Pyon KH; Dahl AR 《Carcinogenesis》1997,18(9):1825-1832
While tobacco smoke has been conclusively identified as a lung carcinogen,
there is much debate over which smoke constituent(s) are primarily
responsible for its carcinogenicity. Previous studies in our laboratory
suggested that highly lipophilic carcinogens are slowly absorbed in the
thicker epithelium of the conducting airways, potentially allowing for
substantial local metabolism. The bioactivation of polycyclic aromatic
hydrocarbons in airway epithelium may, hence, be important in tobacco
smoke-induced carcinogenesis. In the present study, the hypothesis of slow
absorption and substantial local metabolic activation of highly lipophilic
carcinogen in airway epithelium was tested in dogs. A single dose of
tritiated benzo[a]pyrene (BaP) dissolved in a saline/phospholipid
suspension was instilled in the trachea, just anterior to the carina. At
intervals of a few minutes up to 30 min over a 3-h period, blood samples
were drawn from the azygous vein, which drains the area around the point of
instillation, and from the systemic circulation. Tissue samples were taken
at the end of the experiment. The concentration of BaP with depth into the
tracheal mucosa was determined with autoradiography. BaP was slowly
absorbed into the trachea with a half-time of approximately 73 min, which
is consistent with diffusion-limited passage through the epithelium and
lead to local doses in the tracheal epithelium that were more than a
1000-fold those of other tissues. The long retention of BaP in the
epithelium provided the local metabolizing enzymes with high substrate
levels over a long period, resulting in extensive metabolism. At 3 h after
the exposure, 23% of the BaP-equivalent activity remained in the tracheal
mucosa. Of this fraction, 13% was parent compound, 28% was organic
extractable, 31% was water-soluble, and 28-7% of the instilled dose was
bound to tracheal tissues. These results explain the tendency of highly
lipophilic carcinogens, such as BaP, to induce tumors at the site of entry
and, furthermore, indicate that the highly lipophilic components of tobacco
smoke and polluted air may be the most important contributors to lung
tumors of the conducting airways.
相似文献
102.
薄层扫描法测定熊胆引流物中胆汁酸含量 总被引:4,自引:0,他引:4
熊胆向以贵重药材闻名,被称之为稀有药品,为开发熊胆资源,解决熊胆奇缺问题,我校解剖教研室已成功地完成了人工引流熊胆汁技术,可随时进行人工引流获取熊胆汁。为了确定胆汁的质量指标,了解其主要成分,我们进行了引流胆汁与天然熊胆的分析。文献报道,熊胆中主要含熊去氧胆酸(ursodesoxycholic acid,UDCA)、鹅去氧胆酸(cheno desoxycholic acid,CDCA)、胆酸(cholic acid,CA)、去氧胆酸(deoxycholic,acid DCA)等。 相似文献
103.
红豆杉提取物中紫杉醇的反相高效液相色谱法测定 总被引:2,自引:0,他引:2
本文报道应用反相高效液相色谱法测定红豆杉提取物中紫杉醇的含量,以倍他米松作内标,在填充以10μm LiChrosorb RP-18固定相的250×4mm不锈钢柱上以甲醇-水(30:10v/v)作流动相。228 nm处检测。本法简便、快速、准确,适用于微量样品的测定。 相似文献
104.
Hakeem AR Verbeke CS Cairns A Aldouri A Smith AM Menon KV 《Hepatobiliary & pancreatic diseases international : HBPD INT》2014,13(4):435-441
BACKGROUND: Laparoscopic pancreaticoduodenectomy (LPD) is a safe procedure. Oncological safety of LPD is still a matter for debate. This study aimed to compare the oncological outcomes, in terms of adequacy of resection and recurrence rate following LPD and open pancreaticoduodenectomy (OPD).METHODS: Between November 2005 and April 2009, 12 LPDs (9 ampullary and 3 distal common bile duct tumors) were performed. A cohort of 12 OPDs were matched for age, gender, body mass index (BMI) and American Society of Anesthesiologists (ASA) score and tumor site.RESULTS: Mean tumor size LPD vs OPD (19.8 vs 19.2 mm, P=0.870). R0 resection was achieved in 9 LPD vs 8 OPD (P=1.000). The mean number of metastatic lymph nodes and total number resected for LPD vs OPD were 1.1 vs 2.1 (P=0.140) and 20.7 vs 18.5 (P=0.534) respectively. Clavien complications grade I/II (5 vs 8), III/IV (2 vs 6) and pancreatic leak (2 vs 1) were statistically not significant (LPD vs OPD). The mean high dependency unit (HDU) stay was longer in OPD (3.7 vs 1.4 days, P<0.001). There were 2 recurrences each in LPD and OPD (log-rank, P=0.983). Overall mortality for LPD vs OPD was 3 vs 6 (log-rank, P=0.283) and recurrence-related mortality was 2 vs 1. There was one death within 30 days in the OPD group secondary to severe sepsis and none in the LPD group.CONCLUSIONS: Compared to open procedure, LPD achieved a similar rate of R0 resection, lymph node harvest and long-term recurrence for tumors less than 2 cm. Though technically challenging, LPD is safe and does not compromise oncological outcome. 相似文献
105.
Jia-Min Zhou Lu Wang An-Rong Mao 《Hepatobiliary & pancreatic diseases international : HBPD INT》2023,22(6):570-576
Background: More than 50% of patients with colorectal cancer develop liver metastases. Hepatectomy is the preferred treatment for resectable liver metastases. This review provides a perspective on the utility and relevant prognostic factors of repeat hepatectomy in recurrent colorectal liver metastasis(CRLM). Data sources: The keywords “recurrent colorectal liver metastases”, “recurrent hepatic metastases from colorectal cancer”, “liver metastases of colorectal cancer”, “repeat hepatectomy”, “re... 相似文献
106.
107.
In this study we investigated whether the diagnosis of sleep apnoea syndrome (SAS), based on night-time polysomnography (NPSG), can be predicted or excluded by a one-hour daytime polysomnography (DPSG). The results of 306 NPSGs were compared with DPSGs, which were performed the day before. Treated patients were excluded. In the 89 patients with SAS (Apnoea index (AI)>/=5) 59 showed apnoeas during the DPSG and 30 did not. In the 217 without SAS 25 showed apnoeas daring DPSG and 192 did not. Sensitivity for detecting SAS was 66%, the specificity was 88%, the positive predictive value (PPV) 70% and the negative predictive value (NPV) 86%. For relevant SAS (AI>/=10) the NPV would be 95%. We conclude that the one-hour DPSG is not sufficient for diagnosing or excluding SAS with certainty. It can be used to make the presence of relevant SAS unlikely. 相似文献
108.
109.
110.
Muhammed KANDEMR Necdet Fatih YAAR Mete
ZKURT Rumeysa
ZYURT Nuriye Ezgi BEKTUR AYKANAT Nilüfer ERKASAP 《Turkish Journal of Medical Sciences》2021,51(4):2177
Background/aim Even though interleukin-1 receptor antagonist, IL-1Ra, is used in certain inflammatory diseases, its effect on ischemia-reperfusion injury is a current research topic. We aimed to investigate the protective effects of anakinra, an IL-1Ra, on the I/R induced intestinal injury.Materials and methods The rat model of intestinal ischemia-reperfusion was induced. Rats were randomized into 4 groups: (group 1) control group, (group 2) I/R group, (group 3 and 4) treatment groups (50 mg/kg and 100 mg/kg, respectively). Gene expressions of caspase-3, TNF-α, IL-1α, IL-6, and apoptotic cells in tissue samples were evaluated by PCR and TUNEL methods, respectively. Plasma levels of superoxide dismutase (SOD), catalase (CAT), and malondialdehyde (MDA) were studied by the ELISA method and tissue samples were examined histopathologically as well.Results Anakinra inhibited the expression of IL-1α, IL-6, and TNF-α and decreased the SOD, CAT, and MDA caused by ischemia-reperfusion injury in both treatment groups. Caspase-3 expression and TUNEL-positive cell number in treatment groups were also less. Histopathologically, anakinra better preserved the villous structure of the small intestine at a dose of 100 mg/kg than 50 mg/kg. Conclusion Anakinra decreased the intestinal damage caused by ischemia-reperfusion and a dose of 100 mg/kg was found to be histopathologically more effective. 相似文献