Conformation and gas permeability of poly(α-amino acid) membranes

The permeability of some poly(?-amino acid) (PAA) membranes like such of poly(N,δ-carbobenzoxy-L -lysine) (PCBL), poly(N,δ-carbobenzoxy-L -ornithine) (PCBO) as well as of copolymers of L -lysine and carbobenzoxy-L -lysine to oxygen and carbon dioxide were determined at different water content especially with regard to their use for artificial lungs. The conformations of these polymer membranes were studied by means of IR-spectra and X-ray diffraction. The results on the diffusion coefficient obtained for PCBL and PCBO were analysed in terms of Eyring's theory. They suggest that the microvoids in the interstices between the α-helices, assumed on the basis of X-ray analyses, play an important role, especially below the glass transition temperature T_g of the side-chains. This seems also to contribute partly to the diffusion of gas through the membrane even above T_g and results in an abnormally high “apparent activation energy” of diffusion in the wet state below T_g. It was found that the permeability of the membrane of partially decarbobenzoxylated PCBL for oxygen in a certain temperature range is higher than that for carbon dioxide. This has never been observed for any other synthetic polymer, because usually carbon dioxide has a higher solubility in these materials than oxygen. In the case of the partially decarbobenzoxylated PCBL membranes, however, the diffusion coefficient of carbon dioxide, and therefore the permeation of this gas, decreases much more than that of oxygen with increasing decarbobenzoxylation accompanied by the formation of β-structure and concomitantly the formation of intermolecular hydrogen bonds. Obviously, this phenomenon may be responsible for the permselectivity of these membranes for oxygen compared with carbon dioxide.     

Effects of low-level microwave irradiation on amphetamine hyperthermia are blockable by naloxone and classically conditionable

In a series of experiments, we investigated the effects of pulsed low-level microwave irradiation on amphetamine-induced hyperthermia in the rat. Rats were irradiated in a 2,450-MHz cylindrical waveguide exposure system at 1 mW/cm², 2 s pulses, 500 pps, average SAR of 0.6 W/kg. Acute (45 min) exposure to microwaves attenuated amphetamine-induced hyperthermia. This effect was blocked by pretreatment of the animals with the narcotic antagonist naloxone. In another experiment, rats were subjected to ten daily sessions of microwave exposure (45 min/session). On day 11, amphetamine-induced hyperthermia was studied in the animals immediately after a session of either microwave or sham exposure. Similar to the acute effect, amphetamine-induced hyperthermia was attenuated in rats irradiated with microwaves (unconditioned effect). In the sham-irradiated animals we observed a potentiation of the amphetamine-induced hyperthermia, which was a conditioned effect of microwaves. Thus, the conditioned effect (potentiation) was opposite in direction to the unconditioned effect (attenuation). No tolerance developed to the unconditioned effect after subchronic exposure. Furthermore, both conditioned and unconditioned effects of microwaves on amphetamine-induced hyperthermia could be blocked by treatment with naloxone. These data suggest that (1) microwave irradiation may activate endogenous opioids, which in turn alter the actions of psychoactive drugs, and (2) the effect of microwaves on drug action can be classically conditioned. Offprint requests to: H. Lai     

Reduction in Maternal Energy Intake during Lactation Decreased Maternal Body Weight and Concentrations of Leptin,Insulin and Adiponectin in Human Milk without Affecting Milk Production,Milk Macronutrient Composition or Infant Growth

Maternal diet has the potential to affect human milk (HM) composition, but very few studies have directly assessed the effect of maternal diets on HM composition. The primary aim of this study was to assess the effect of improving dietary quality in lactating women over 2 weeks on the concentrations of macronutrients and metabolic hormones in HM. The secondary aims were to assess the impact of the dietary intervention on 24 h milk production, maternal body composition and infant growth. Fifteen women completed a 1-week baseline period followed by a 2-week dietary intervention phase targeted towards reducing fat and sugar intake. Maternal anthropometric and body composition and infant growth measurements were performed weekly. Total 24 h milk production was measured before and after the dietary intervention, and HM samples were collected daily. Maternal intakes of energy (−33%), carbohydrate (−22%), sugar (−29%), fat (−54%) and saturated fat (−63%) were significantly reduced during the dietary intervention. HM insulin, leptin and adiponectin concentrations were 10–25% lower at the end of the dietary intervention, but HM concentrations of macronutrients were unaffected. Maternal body weight (−1.8%) and fat mass (−6.3%) were significantly reduced at the end of the dietary intervention, but there were no effects on 24 h milk production or infant growth. These results suggest that reducing maternal energy, carbohydrate, fat and sugar intake over a 2-week period is associated with significant reductions in HM insulin, leptin and adiponectin concentrations. These changes may be secondary to decreases in maternal weight and fat mass. The limited studies to date that have investigated the association between metabolic hormone concentrations in HM and infant growth raise the possibility that the changes in HM composition observed in the current study could impact infant growth and adiposity, but further studies are required to confirm this hypothesis.     

中孕期胎儿染色体异常高危孕妇羊水细胞胎儿染色体核型及介入性产前诊断指征的大样本分析

目的探讨中孕期胎儿染色体异常(FCA)高危孕妇羊水细胞胎儿染色体核型(FK)及其介入性产前诊断(IPD)指征。方法选择2014—2018年,在四川大学华西第二医院产前诊断中心进行羊膜腔穿刺术羊水细胞FK检测的63581例FCA高危孕妇(孕龄为19~27+6孕周)为研究对象。回顾性分析孕妇不同IPD指征及其胎儿染色体核型异常(FKA)检测结果。本研究遵循的程序符合四川大学华西第二医院伦理委员会所制定的伦理学标准,并通过该伦理委员会批准[审批文号:医学科研2019伦审批第(077)号]。结果①本组63581例中孕期孕妇的FKA检出率为3.13%(1989/63581)。这63581例孕妇的IPD指征分别为高龄(预产期年龄≥35岁)(25648例)、血清学筛查高风险(29009例)、无创产前筛查(NIPT)高风险(333例)、夫妇一方为染色体异常携带者(603例)、超声筛查发现胎儿结构异常及超声软指标异常(2647例)、异常儿生育史(1546例)、于外院进行羊水细胞FK分析结果异常者(7例)、孕妇智力低下及合并智力低下家族史(149例)、孕妇早孕期有害物质接触史(1400例)、其他(2239例),FKA检出率分别为3.26%(836/25648)、2.04%(593/29009)、65.17%(217/333)、34.33%(207/603)、3.51%(93/2647)、1.68%(26/1546)、85.71%(6/7)、4.03%(6/149)、0.14%(2/1400)、0.13%(3/2239)。②351例孕妇的IPD指征为超声筛查发现胎儿结构异常中,IPD指征为胎儿淋巴水囊瘤、皮肤水肿的FKA检出率最高,为26.09%(6/23)。2296例孕妇的IPD指征为胎儿超声软指标异常中,IPD指征为胎儿颈项透明层(NT)值≥2.5 mm的FKA检出率最高,为7.74%(66/853)。结论孕妇高龄、血清学筛查高风险、NIPT高风险、夫妇一方为染色体异常携带者、超声筛查发现胎儿结构异常及超声软指标异常等,均为中孕期孕妇FCA的IPD指征,孕妇IPD指征类型不同,FCA风险不同。羊膜腔穿刺术羊水细胞FK检测,可预测有IPD指征孕妇的妊娠结局,为降低FKA出生率提供参考。     

胃癌术中动脉区域灌注化疗与全身静脉化疗的临床疗效比较

目的　评价胃癌术中动脉区域灌注化疗药物的临床疗效。方法　对 40例经病理确诊的胃癌患者 (治疗组 )于术中经供应肿瘤的区域动脉行插管化疗 ,同时进行手术治疗 ,并与同期术中行全身静脉化疗的 2 4例胃癌患者 (对照组 )进行临床疗效比较。结果　术后病理检查显示 ,治疗组原发灶中的癌细胞均有不同程度地变性坏死 ,其近期有效率为 95 % ,对照组有效率为 41.6 7% ,两组比较差异显著 (P<0 .0 5 )。结论　胃癌患者术中经动脉灌注化疗 ,其近期抗癌效果好 ,毒副反应轻 ,对减少或防止术中癌细胞的医源性扩散与种植以及术后复发 ,均有重要的临床意义     

前次妊娠期糖尿病临床特征对再次妊娠复发性糖尿病影响

目的:分析前次妊娠期糖尿病(GDM)的临床特征对再次妊娠糖尿病复发影响。方法:回顾性收集2017年1月-2019年10月本院产科常规产前检查且前次妊娠诊断为GDM的306例产妇临床资料,根据本次妊娠GDM诊断标准分为复发性GDM组与血糖正常组,再根据葡萄糖耐量试验(OGTT)各时间点血糖水平将复发性GDM组分为复发性GDM A组(单纯FPG异常)、复发性GDM B组(FPG正常但1hPG或/和2hPG异常)、复发性GDM C组(FPG异常,同时合并1hPG或/和2hPG异常)。比较各组前次妊娠临床特点与复发关系。结果:复发性GDM组与血糖正常组年龄、产次间隔≥5年比例、前次妊娠FPG、1hPG、2hPG值及OGTT异常类型比例、前次妊娠应用胰岛素比例均有差异(P<0.05),而前次妊娠前体质指数、妊娠期增重及早产发生情况无差异(P>0.05);年龄≥35岁、前次妊娠2hPG>9.10mmol/L、1hPG或(和)2hPG异常及FPG+1hPG或(和)2hPG异常是复发性GDM的危险因素(P<0.05),而产次间隔≥5年、前次妊娠OGTT FPG>5.35mmol/L、1hPG>10.59mmol/L、前次妊娠应用胰岛素与复发性GDM无相关性(P>0.05);复发性GDM C组与A组年龄、前次妊娠OGTT 1hPG、2hPG值有差异(P<0.05),而复发性GDM C组与B组、B组与A组比较无差异(P>0.05);复发性GDM A组、B组、C组前次妊娠OGTT异常类型构成比有差异(P<0.001),产次间隔时间≥5年、前次妊娠早产、应用胰岛素比例无差异(P>0.05);年龄≥35岁及前次妊娠FPG+1hPG或(和)2hPG异常是GDM复发时血糖异常类型高等级的危险因素(P<0.05),前次妊娠OGTT 1hPG>10.59mmol/L、2hPG>9.10mmol/L、前次妊娠1hPG或(和)2hPG异常与复发性GDM孕妇OGTT异常类型无相关性(P>0.05)。结论:孕妇年龄、前次妊娠OGTT 2hPG值及异常类型可能会影响再妊娠复发性GDM的发生率及严重程度。     

Familial Transmission of Alcohol Use Norms and Expectancies and Reported Alcohol Use

Members of 183 families (biological parents and one adult offspring) completed questionnaires on their quantity and frequency of alcohol use, what they would consider a "normal" quantity-frequency of alcohol use, "problem" quantity-frequency of use, flushing after alcohol use, and other expected physiological and subjective responses to alcohol. Within individuals, own quantity-frequency of alcohol use was moderately negatively correlated with flushing after one drink or less ("fast flushing"), but more highly positively correlated with judged normal alcohol use and with expected subjective effects. Spouse resemblances were low for quantity-frequency of alcohol use and flushing, but high for alcohol use norms and expected physiological and subjective responses. Parent-offspring resemblances were low to moderate for own alcohol use and flushing, but moderate to high for expected physiological and subjective effects. These results were discussed in terms of the effects of genetically transmitted flushing after alcohol use and culturally transmitted alcohol norms and expectations on alcohol use.     

Site of bone density measurement may affect therapy decision

Summary The purpose of this study was to determine whether bone mineral density (BMD) measurements at the lumbar spine and femoral neck provided comparable information to women planning to use that knowledge to help them make a decision about hormone replacement therapy. Eighty-eight healthy Caucasian women, aged 44–59 and within 0 to 5 years of menopause, participated in the study. BMD measurements were performed at the lumbar spine (L1-L4) and the femoral neck by dual energy X-ray absorptiometry (DXA). Criteria suggested by the National Osteoporosis Foundation were used to categorize women as at risk for osteoporosis, bone density more than one standard deviation (SD) below the young adult mean, or as low risk, bone density at or above this level. The re that 46 women would be classified into the low risk category on the basis of spinal BMD alone. However, 28 of these 46 women would fall into the at risk category when the femoral neck BMD was measured. Sixty-one percent of women informed they were at low risk on the basis of spinal BMD would be considered at risk based on femoral neck BMD. When femoral neck BMD was used as the primary risk indicator, 14% of the women classified as low risk would be at risk if spinal BMD were added. These results suggest that both lumbar spine and proximal femur measurements should be made when women are using bone density measurements as an aid in deciding whether or not to use hormone therapy in their postmenopausal years.     

Ocular findings in beta-thalassemia

Eye examination was performed in a series of 53 patients whose mean age was 19.5 years (range from 11 to 25 years), affected from Cooley's disease, in treatment with transfusions and desferrioxamine in subcutaneous infusion. The most frequent ocular change was fundus mottling appearance like "leopard skin" (15%). We found also lens opacity (11%), drusen (7%), retinal venous tortuosity (5%), without impairment of visual acuity. The pathogenic factors of the ocular change are related to abnormality of iron metabolism. These results suggest that the involvement of desferrioxamine to remove iron from the eyeball is relatively small.     

毫米波辐射对白血病细胞的细胞结构、自由基和bcl-2基因表达的影响

目的 研究毫米波辐射对白血病细胞株的细胞结构、培养体系中的氧化自由基和抗氧化酶系,以及bcl-2基因表达的影响。方法 电镜显微技术研究细胞结构的变化,AnnexinV/PI双染法结合流式细胞术分析细胞株凋亡和坏死,硫代巴比妥酸（TBA）法和邻苯三酚法测定细胞株培养体系中的脂质过氧化物（LPO）和超氧化物歧化酶（SOD）的含量变化;流式细胞仪结合荧光标记抗体检测bcl-2基因表达。结果 毫米波辐射使白血病细胞株细胞结构产生显著的退行性变化,显著诱导细胞凋亡和坏死,抑制细胞活力,脂质过氧化物含量上升,SOD含量下降,bcl-2基因的表达显著下降。结论 毫米波辐射有明显的诱导白血病细胞凋亡的效应,其机制与辐射后氧化自由基水平上升、抗氧化酶系活性下降及bcl-2基因的表达下降有关。