低强度微波辐射对大鼠神经细胞死亡率影响的实验研究

目的 探讨低强度微波辐射对大鼠神经细胞死亡率的影响。方法 在对体外新生大鼠(0～1天)皮层神经细胞进行原代培养的基础上,以频率900MHz,功率密度分别为0．025mW／cm^2、0．05mW／cm^2、0．1mW／cm^2的低强度微波辐射4、8、12、16、20、24小时。检测细胞死亡率。结果 和对照组相比,0．05mW／cm^2功率密度组辐射12小时、0．1mW／cm^2功率密度组辐射8小时后均可引起神经细胞细胞死亡率增高,且随着辐射时间的延长,细胞死亡率也逐渐上升,0．025mW／cm^2功率密度组未见明显改变。结论 长期连续的低强度微波辐射对培养大鼠神经细胞存在损伤作用。     

Effects of laser irradiation on the spinal cord for the regeneration of crushed peripheral nerve in rats

BACKGROUND AND OBJECTIVE: The purpose of the present study was to examine the recovery of the crushed sciatic nerve of rats after low-power laser irradiation applied to the corresponding segments of the spinal cord. STUDY DESIGN/MATERIALS AND METHODS: After a crush injury to the sciatic nerve in rats, low-power laser irradiation was applied transcutaneously to corresponding segments of the spinal cord immediately after closing the wound by using 16 mW, 632 nm He-Ne laser. The laser treatment was repeated 30 minutes daily for 21 consecutive days. RESULTS: The electrophysiologic activity of the injured nerves (compound muscle action potentials--CMAPs) was found to be approximately 90% of the normal precrush value and remained so for up to a long period of time. In the control nonirradiated group, electrophysiologic activity dropped to 20% of the normal precrush value at day 21 and showed the first signs of slow recovery 30 days after surgery. The two groups were found to be significantly different during follow-up period (P < 0.001). CONCLUSION: This study suggests that low-power laser irradiation applied directly to the spinal cord can improve recovery of the corresponding insured peripheral nerve.     

低度酒蒸馏方程的推导

根据蒸馏酒理论采用微积分方法，以酒精质量分数与相对密度的对照表以及蒸馏时原酒液质量分数与蒸馏液质量分数对照表两组基础数据为依据，推导了原酒液酒度随蒸馏体积分数变化的关系方程式，进一步推导了以低度酒为原料进行蒸馏的蒸馏液酒度随蒸馏液体积变化的方程式，该方程可用于蒸馏过程酒度控制。     

低氧分压对大鼠勃起功能的影响

目的探讨低氧分压对大鼠勃起功能障碍（ED）的影响。方法48只成年白色雄性SD大鼠随机分为对照组和实验组，每组按照实验时间（2周、6周、10周）分为3个亚组，每个亚组8只。实验组置于密闭低氧舱中饲养，对照组在正常环境中饲养，其他条件相同。分别观察其勃起功能，采用免疫组化SP法检测神经源性一氧化氮合成酶（nNOS）阳性神经纤维的数量、内皮源性一氧化氮合成酶（eNOS）的表达。结果实验组与对照组比较：（1）大鼠勃起次数明显降低（P〈0．001）；（2）nNOS阳性神经纤维数量、eNOS蛋白的表达均有显著性差异（P〈0．01）。实验组间比较：勃起次数6周组明显低于2周组，10周组稍高于6周组；nNOS阳性神经纤维数量有显著性差异（P〈0．01）；eNOS的表达6周组最低，10周组有所回升。结论低氧分压致大鼠勃起功能受损和nNOS、eNOS的表达下降。nNOS染色阳性神经纤维数量的减少、eNOS表达的下降，可能是低氧分压环境中大鼠ED发生的原因之一。     

Are Tri‐Ethnic Low‐Income Women with Breast Cancer Effective Teachers of the Importance of Breast Cancer Screening to Their First‐Degree Relatives? Results from a Randomized Clinical Trial

The purpose of this study was to determine the efficacy of women with breast cancer as teachers of the importance of breast cancer screening to their first-degree female relatives. The sample was restricted to low-income working age women recruited from four hospitals. The study design was a randomized clinical trial. At each hospital, breast cancer patients (probands) were randomized into one of two study groups: (i) intensive, individual educational training on breast cancer screening or (ii) standard clinic education on breast cancer screening. The probands were instructed to teach at least one of their first-degree female relatives (21+ years of age) about breast cancer screening techniques. Three to six months after the enrollment of the probands, their relatives were contacted by telephone to determine breast cancer screening practices. A total of 79 probands and 96 relatives participated in the study. Relatives in the education group when compared with the control group were: 1.25 times more likely to have clinical breast examination (p = 0.005), 2.83 times more likely to have scheduled a clinical breast examination (p = 0.046), and, 1.36 times more likely to have been told about performing breast self-examination (p = 0.05). Additionally, relatives in the education group were more likely to have received a pamphlet on breast cancer screening (RR = 1.58, p = 0.009) and have discussed the importance of breast cancer screening (RR = 1.33, p = 0.020) from the proband. Special education training did not impact mammography utilization of the relatives. From these findings, a tri-ethnic group of low-income women with breast cancer can be effective teachers of breast cancer screening practices, at least for promoting clinical breast examination and transmitting messaging for performance of breast self-examination if given the adequate training.     

CFTR stabilizes ENaC at the plasma membrane

CFTR was reported to regulate ENaC channel opening, decreasing ENaC activity in airways and increasing it in sweat ducts. We generated MDCK-I cell lines stably expressing tagged alphabetagammaENaC+CFTR or ENaC alone, and developed an assay to quantify cell-surface half-life of ENaC. Surprisingly, we found that co-expressed CFTR stabilizes ENaC at the plasma membrane, suggesting that CFTR regulates ENaC stability, not just opening.     

Prolonged administration of secretin to normal rats increases biliary proliferation and secretin-induced ductal secretory activity

Background and aim

Cholangiocyte proliferation is coordinately regulated by a number of gastrointestinal hormones/peptides, some of which display stimulatory effects and some have inhibitory actions on cholangiocyte proliferation. Enhanced biliary proliferation [for example after bile duct ligation (BDL) and partial hepatectomy] is associated with increased expression of secretin receptor (SR), cystic fibrosis transmembrane conductance regulator (CFTR) and Cl^–/HCO₃^– anion exchanger 2 and secretin-stimulated ductal secretion, whereas loss/damage of bile ducts [for example after acute carbon tetrachloride (CCl₄) administration] is associated with reduced secretin-stimulated ductal secretory activity. There is growing information regarding the role of gastrointestinal hormones the regulation of biliary growth. For example, while gastrin, somatostatin and serotonin inhibit bile duct hyperplasia of cholestatic rats by downregulation of cAMP signaling, secretin has been shown to stimulate the proliferation of normal mice by activation of cyclic adenosine 3'',5''-monophosphate (cAMP)-dependent signaling. However, no information exists regarding the stimulatory effects of secretin on biliary proliferation of normal rats. Thus, we evaluated the in vivo and in vitro effect of secretin on biliary proliferation, the expression of markers key of ductal secretion and secretin-stimulated ductal secretion.

Methods

Normal male rats were treated with saline or secretin (2.5 nmoles/kg BW/day by osmotic minipumps for one week). We evaluated: (I) intrahepatic bile duct mass (IBDM) in liver sections and PCNA expression in purified cholangiocytes; (II) SR and CFTR mRNA expression and secretin-stimulated cAMP levels in purified cholangiocytes; and (III) secretin-stimulated bile and bicarbonate secretion in bile fistula rats. In vitro, normal rat intrahepatic cholangiocyte lines (NRIC) were treated with BSA (basal) or secretin (100 nM) for 24 to 72 hours in the absence/presence of a PKA or a MEK inhibitor before evaluating proliferation by MTS assays.

Results

Prolonged administration of secretin to normal rats increased IBDM and PCNA expression in purified cholangiocytes compared to saline-treated normal rats. Also, secretin increased the expression of proteins (SR and CFTR) that are key in the regulating ductal secretion and enhanced secretin-stimulated cAMP levels and bile and bicarbonate secretion. In vitro, secretin increased the proliferation of NRIC, increase that was prevented by PKA and MAPK inhibitors.

Conclusions

We have demonstrated that secretin stimulates both in vivo and in vitro biliary proliferation and secretin-stimulated ductal secretory activity in normal rats. We suggest that the stimulatory effect of secretin on biliary proliferation and secretion may be important for preventing biliary dysfunction during ductopenic disorders.     

Cystic fibrosis transmembrane conductance regulator is correlated closely with sperm progressive motility and normal morphology in healthy and fertile men with normal sperm parameters

Cystic fibrosis transmembrane conductance regulator (CFTR) has been demonstrated to be expressed in mature spermatozoa and correlated with sperm quality. Sperm CFTR expression in fertile men is higher than that in infertile men suffering from teratospermia, asthenoteratospermia, asthenospermia and oligospermia, but it is unknown whether CFTR is correlated with sperm parameters when sperm parameters are normal. In this study, 282 healthy and fertile men with normal semen parameters were classified into three age groups, group (I): age group of 20–29 years (98 cases, 27.1 ± 6.2), group (II): age group of 30–39 years (142 cases, 33.7 ± 2.6) and group (III): age group of more than or equal to 40 years (42 cases, 44.1 ± 4.6). Sperm concentration, total count and progressive motility were analysed by computer‐assisted sperm analysis. Sperm morphology was analysed by modified Papanicolaou staining. Sperm CFTR expression was conducted by indirect immunofluorescence staining. There was a significant positive correlation (P < 0.001) between CFTR expression and sperm progressive motility (r = 0.221) and normal morphology (r = 0.202), but there were no correlations between sperm CFTR expression and semen volume, sperm concentration, sperm total count as well as male age (P > 0.05). Our findings show that CFTR expression is associated with sperm progressive motility and normal morphology in healthy and fertile men with normal sperm parameters, but not associated with the number of spermatozoa and male age.