THE CONTROVERSIAL OVARY

Routine removal of ovaries at hysterectomy has been urged as a means of preventing ovarian carcinoma. Proponents of this policy, however, have not submitted the crucial datum: What proportion of women undergoing hysterectomy for benign conditions will later have ovarian carcinoma if the ovaries are not removed. Granting that oophorectomy will effectively prevent ovarian carcinoma, it creates an endocrine imbalance that cannot be corrected artificially, and the lack of ovarian hormones may precipitate osteoporosis or cardiovascular disease. If the ovaries appear normal, if there is no history of carcinoma, and if the patient understands and accepts the risk, the ovaries usually can be conserved at hysterectomy for benign conditions.     

CONTROVERSIAL PROBLEMS IN ADENOTONSILLECTOMY

It is doubtful that the tonsils or adenoids contribute sufficiently to immunity or to hematopoiesis to warrant withholding adenotonsillectomy when there is need for the operation. Focal infection, rheumatic fever and allergic disease must be evaluated in the individual case. A seldom discussed reason for operation is the prophylaxis or treatment of malformation of the nose, sinuses, mouth and jaw. Well defined indications for adenotonsillectomy include frequent occurrence of infection, peritonsillar abscess, cervical lymph node disease believed caused by tonsillar infection, otitis media, and hypertrophy sufficient to embarrass swallowing or breathing. The operation may also be indicated in certain cases of impaired hearing, halitosis, or anorexia, and sometimes for carriers of diphtheria.Psychic trauma can be obviated by proper preparation of a child for the operation he is to undergo.There is a good evidence of evidence of relationship between recent adenotonsillectomy and infection with poliomyelitis—and a good deal of evidence to the contrary. Nationwide rules cannot be established on the basis of the evidence presented thus far. Since in many cases it is unwise to put off adenotonsillectomy, each case in each community in each season must be evaluated separately.     

木质部导管空穴化研究中的几个热点问题

 导管的空穴化和栓塞化现象是目前国际上水分生理生态研究的一个热点。该文对导管空穴化和栓塞化研究中出现的几个热点问题进行了概括和总结。1）在研究导管空穴化的实验手段上,超声波传感器探测法具有一定的局限性;目前至少存在4种可能的原因来解释木质部压力探针法（XPP）和压力室法所测得的导管水柱张力不一致的现象;近来出现的核磁共振成像法可以进行导管空穴化的无损伤检测。2）导管解剖学特征与形成空穴的可能性之间的关系可能与树种相关。3）导管空穴化引起气孔关闭的作用机制目前还不太清楚。4）植物防止空穴化产生的能力与适应干旱能力之间的关系还没有定论。5）单独用根压来解释空穴化导管的重新注水机制是不全面的,还存在其它重新注水机制。