2009年2月2日星期一

Cabbage can be anti-cancer(卷心菜可防癌)

New study: how certain vegetables combat cancerScientists in University of California reported on Tuesday that their new research has shown how the healing power of these vegetables works at the cellular level.While it has been known for some time that eating cruciferous vegetables, such as broccoli, can help prevent breast cancer, the mechanism by which the active substances in these vegetables inhibit cell proliferation was unknown -- until now.Scientists in University of California reported on Tuesday that their new research has shown how the healing power of these vegetables works at the cellular level.The study results was published in this month's journal Carcinogenesis."Breast cancer can be protected against by eating cruciferous vegetables such as cabbage and near relatives of cabbage such as broccoli and cauliflower," said author Olga Azarenko. "These vegetables contain compounds called isothiocyanates which we believe to be responsible for the cancer-preventive and anti- carcinogenic activities in these vegetables."Their research focuses on the anti-cancer activity of one of these compounds, called sulforaphane, or SFN. It has already been shown to reduce the incidence and rate of chemically induced mammary tumors in animals. It inhibits the growth of cultured human breast cancer cells.The researchers made the surprising discovery that SFN inhibits the proliferation of human tumor cells by a mechanism similar to the way that the anticancer drugs inhibit cell division. However SFN is much weaker than these other plant-based drugs, and thus much less toxic."SFN may be an effective cancer preventive agent because it inhibits the proliferation and kills precancerous cells," said the authors. It is also possible that it could be used as an addition to anticancer drugs to increase effective killing of tumor cells without increased toxicity.

艾滋病机会感染的临床表现?

所谓机会感染,即条件致病因素,是指一些侵袭力较低、致病力较弱的微生物,在人体免疫功能正常时不能致病,但当人体免疫功能减低时则为这类微生物造成一种感染的条件,乘机侵袭人体致病,故称作机会性感染。尸检结果表明,90%的艾滋病人死于机会感染。能引起艾滋病机会感染的病原多达几十种,而且常多种病原混合感染。主要包括原虫、病毒、真菌及细菌等的感染。1.原虫类(1)卡氏肺囊虫肺炎:卡氏肺囊虫是一种专在人的肺内造穴打洞的小原虫。人的肉眼看不见,而且用一般的生物培养方法也找不到。卡氏肺囊虫肺炎主要通过空气与飞沫经呼吸道传播。健康人在感染艾滋病毒后,免疫功能受到破坏,这时卡氏肺囊虫便乘虚而入,在病人体内大量繁殖,使肺泡中充满渗出液和各种形态的肺囊虫,造成肺部的严重破坏。卡氏肺囊虫肺炎在艾滋病流行前是一种不常见的感染,过去仅发现于战争、饥饿时期的婴幼儿,或者接受免疫抑制治疗的白血病患儿。卡氏肺囊虫肺炎是艾滋病患者的一个常见死因,在60%以上的艾滋病患者中属于最严重的机会感染,约有80%的艾滋病患者至少要发生一次卡氏肺囊虫肺炎。艾滋病患者合并卡氏肺囊虫肺炎时,首先有进行性营养不良、发热、全身不适、体重减轻、淋巴结肿大等症状。以后出现咳嗽、呼吸困难、胸痛等症状,病程4~6周。发热(89%)和呼吸急促(66%)为肺部最常见的体征。某些人肺部还可听到罗音。卡氏肺囊虫肺炎常复发,病情严重,是艾滋病患者常见的致死原因。卡氏肺囊虫肺炎病人胸片显示两肺广泛性浸润。但少部分患者(约占23%)其胸片可示正常或极少异常。据对180例卡氏肺囊虫肺炎X线胸片检查所见,表现为两侧间质性肺炎的77例,间质及肺泡炎症45例,肺门周围的间质炎症26例,单侧肺泡及间质炎症24例,未见异常者8例。肺功能测定示肺总量及肺活量下降,随着病程的进展而进一步加剧。气管镜或肺穿刺所取之标本可以查到卡氏肺囊虫,有时还可以查到其它病原体,此时为混合性机会感染。本病病程急剧;亦可缓慢,终因进行性呼吸困难、缺氧、发展为呼吸衰竭而死亡,其病死率可达90%~100%。(2)弓形体感染:艾滋病人得弓形体感染主要引起神经系统弓形体病,其发生率为26%。临床表现为偏瘫,局灶性神经异常,抽搐、意识障碍及发热等。CT检查可见单个或多个局灶性病变。依据组织病理切片或脑脊液检查可见弓形体。极少数弓形体累及肺部(1%)。该病是由寄生性原虫动物鼠弓浆虫所致的一种动物传染病。人的感染途径,先天性感染是由母亲经胎盘传给胎儿.后天性感染是因吃了含有组织囊虫的生肉或未煮熟的肉而感染。(3)隐孢子虫病:孢子虫是寄生于家畜和野生动物的小原虫,人感染后,附于小肠和大肠上皮,主要引起吸收不良性腹泻,病人表现为难以控制的大量水样便,每日5~10次以上,每天失水3~10升,病死率可高达50%以上。诊断靠肠镜活检或粪便中查到原虫的卵囊。2.病毒类(1)巨细胞病毒感染:根据血清学调查表明,巨细胞病毒广泛存在,多数巨细胞病毒感染者无症状,但巨细胞病毒感染的病人可在尿、唾液、粪便、眼泪、乳汁和精液中迁延排出病毒。并可经输血、母亲胎盘、器官移植、性交、吮哺母乳等方式传播。艾滋病伴巨细胞病毒感染时,常表现为肝炎、巨细胞病毒肺炎、巨细胞病毒性视网膜炎、血小板和白细胞减少、皮疹等。确诊巨细胞病毒感染必需在活检或尸解标本中找到包涵体或分离出病毒。根据Guarda等对13例艾滋病人尸解的研究,最常见的诊断是巨细胞病毒感染(12例),其次是卡波济氏肉瘤(l0例)。所有12例巨细胞病毒感染均为播散性,并且经常影响两个或多个器官。(2)单纯疱疹病毒感染:其传播途径主要是直接接触和性接触,也可经飞沫传染,病毒可由呼吸道、口、眼、生殖器粘膜或破报皮肤侵入人体。孕妇在分娩时亦可传给婴儿。感染病毒后可引起艾滋病患者皮肤粘膜损害、累及口周、外阴、肛周、手背或食道以至支气管及肠道粘膜等,以唇缘、口角的单纯疱疹最常见,其损害呈高密集成群的小水疱,基底稍红,水疱被擦破后可形成溃疡,其溃疡特点为大而深且有疼痛,常伴继发感染,症状多较严重,病程持续时间长,病损部位可培养出单纯疱疹病毒,活检可查到典型的包涵体。(3)EB病毒:该病毒在艾滋病人中感染率很高,有96%的艾滋病人血清中可检测到EB病毒抗体,EB病毒可致原发性单核细胞增多症,伴溶血性贫血、淋巴结肿大、全身斑疹,T细胞减少等。3.真菌类(1)念珠菌感染:白色念珠菌是一种条件致病真菌,常存在于正常人的皮肤、口腔、上呼吸道、肠道和阴道粘膜上,可从皮肤和粘膜分泌物、大小便、痰液中培养出来。当人体抵抗力降低或机体菌群失调时,可使白色念珠菌变为致病菌导致念珠菌感染。可分为皮肤念珠菌病和粘膜念珠菌病,后者多见为鹅口疮--口腔粘膜、舌及咽喉、齿龈或唇粘膜上的乳白色薄膜,易剥离,露出鲜湿红润基底。多见于严重疾病的晚期,或艾滋病毒感染者。如果同性恋者持续有鹅口疮无其他原因解释时,往往表明患者已感染了艾滋病毒或将发展为艾滋病的指征。念珠菌性食道炎可造成吞咽困难及疼痛或胸骨后疼痛,食道镜检查可见食道粘膜有不规则溃疡和白色伪膜。其它尚有念球菌性口角炎、念珠菌性阴道炎、念珠菌性龟头包皮炎、内脏念珠菌病等。皮肤、粘膜念珠菌病的诊断有赖于临床表现和求助于真菌检查。(2)隐球菌病:是由新型隐球菌感染引起的一种急性或慢性深部真菌病。当机体抵抗力减弱时,容易经呼吸道,偶可经肠道或皮肤入侵致病。隐球菌脑膜炎是艾滋病常见的并发症。有很高的病死率,表现为发热、头痛、精神错乱及脑膜刺激症状。肺部隐球菌,以亚急性或慢性发病,伴咳嗽、粘痰、低热、胸痛、乏力、X线检查为非特异性改变。对隐球菌病的诊断主要依据临床表现和真菌检查确诊。4.细菌类(1)结核杆菌:结核病常发生于有艾滋病感染但尚无艾滋病的病人,这可能因为结核杆菌的毒力强于其它与艾滋病相关的病原体,如卡氏肺囊虫等,所以结核病更易发生于免疫缺陷早期。74%~100%的艾滋病感染伴结核病人有肺结核,其症状和体征常很难鉴别于其他艾滋病相关的肺部疾病。艾滋病患者常表现为扩散性的感染。艾滋病感染病人并发结核最突出临床特征是高发肺外结核,艾滋病伴结核病人或发现结核而诊断艾滋病人中70%以上有肺外结核。艾滋病伴肺外结核最常见的形式为淋巴结炎和粟粒性病变,还常波及骨髓、泌尿生殖道和中枢神经系统。(2)非典型分枝杆菌感染:为艾滋病的重要并发症之一,常波及肝、肺、脾、肾、血液、骨髓、胃肠道、淋巴结等,其表现为发热、消瘦、吸收不良、淋巴结肿大、肝脾肿大。实验室检查为非特异性,确诊靠病原分离培养及活检。(3)其他常见的致病菌:绿脓杆菌、大肠杆菌、伤寒杆菌、淋球菌等均可引起机会感染。

太咸的食物吃多了会伤头发

头发脱落、发质枯黄、没有光泽已成为很多人地心病,有研究表明,这和饮食有一定地关系,吃地太咸或太甜不仅会造成营养代谢性脱发,还会让头发变得枯黄。
  首先,平时吃咸地多了会导致头发枯黄。盐分可造成头发内滞留水分过多,影响它地正常生长发育,导致乌发变“枯草”。同时,头发里过多地盐分给细菌滋生提供了良好地场所,易导致头皮疾病。食盐太多还会诱发多种皮脂病,造成头屑增多,加重脱发。  从中医理论上讲,肾气盛则头发乌黑有光泽,肾气虚则头发干涩而枯黄。近年来,国外很多研究也表明,饮食过咸会增加肾脏地负担,进一步引起排钠障碍,从而使血压升高、蛋白代谢紊乱,影响头发中蛋白地形成,使头发地颜色变淡,甚至枯萎。
  其次,吃糖过多也会引起脱发。过量地糖在人体地新陈代谢过程中,形成大量地有机酸,扰乱头发地色素代谢,使头发逐渐失去光泽,变得枯黄。
  从营养上说,头发所需地是脂肪、蛋白质、维生素A、维生素B6及碘等营养物质,它主要来源于绿色蔬菜、薯类、豆类和海藻类。绿色蔬菜有助于黑色素生成;豆类能增加头发地弹性和润泽度,防止分叉;海菜、海带等海藻类食物含丰富地钙、钾、碘,可预防白发。

Talking About Prostate Cancer

Talking About Prostate Cancer
Every week, New York Times editor Dana Jennings writes about his experiences living with prostate cancer. This week, instead of his regular blog post, Dana has invited us into his home to meet his family and learn more about his treatment in the latest Well video, “Living With Prostate Cancer,” produced by my colleague, Times video journalist Dave Frank.In the video, he talks about the overwhelming response from readers since he began writing about his cancer in mid-November.“I think being willing to be blunt and honest about having prostate cancer really gave this group of men and women permission to talk about things that I don’t think any of them have talked about,” Dana says. “Literally, I feel since that first post went up on November 11, that my life has changed.”Hear more from Dana by watching the full video, below. Then join in the discussion by adding a comment. To read all of Dana’s past posts about living with prostate cancer, click on the Prostate Cancer Journal icon, “One Man’s Story,” above.NYT_VideoPlayerStart