阿片受体拮抗剂在TNF－α所致体温升高中的作用

为探索细胞介素ＴＮＦ－α升体温效应与下丘脑前部、视前区（ＰＯＡＨ）中的阿片受体的关系。应用脑神经核团微量注射方法给自由状态下的雄性ＳＤ大鼠ＰＯＡＨ区微量注射ＴＮＦ－α致热源。给药前３０ｍｉｎ分别用通常阿片受体拮抗剂Ｎａｌ（１０～２０μｇ）和特异性阿片受体μ、δ和κ的拮抗剂ＣＴＡＰ（１．０～２．５μｇ）、ＮＴＩ（０．２５～０．５μｇ）和ｎｏｒ－ＢＮＩ（０．１～３μｇ）对ＰＯＡＨ做预处理。结果：单独给ＴＮＦ－α可致剂量相关的体温升高△Ｔ（１℃～１．４℃）；经Ｎａｌ１０μｇ，ＣＴＡＰ１．０μｇ和ＮＴＩ０．５μｇ处理后使ＴＮＦ－α的升体温效应减弱；用Ｎａｌ２０μｇ，ＣＴＡＰ２．５μｇ和ＮＴＩ０．２５μｇ处理后可完全阻断ＴＮＦ－α所致的体温升高；ｎｏｒ－ＢＮＩ（０．１～３μｇ）对ＴＮＦ－α的升体温效应无影响。     

Anesthesia with halothane and nitrous oxide alters protein and amino acid metabolism in dogs

General anesthesia in combination with surgery is known to result in negative nitrogen balance. To determine whether general anesthesia without concomitant surgery decreases whole body protein synthesis and/or increases whole body protein breakdown, two groups of dogs were studied: Group 1 (n = 6) in the conscious state and Group 2 (n = 8) during general anesthesia employing halothane (1.5 MAC) in 50% nitrous oxide and oxygen. Changes in protein metabolism were estimated by isotope dilution techniques employing simultaneous infusions of [4,53H]leucine and alpha-[1-14C]-ketoisocaproate (KIC). Total leucine carbon flux was unchanged or slightly increased in the anesthetized animals when compared to the conscious controls, indicating only a slight increase in the rate of proteolysis. However, leucine oxidation was increased (P less than 0.001) by more than 80% in the anesthetized animals when compared with their conscious controls, whereas whole body nonoxidative leucine disappearance, an indicator of whole body protein synthesis, was decreased. The ratio of leucine oxidation to the nonoxidative rate of leucine disappearance, which provides an index of the catabolism of at least one essential amino acid in the postabsorptive state, was more than twofold increased (P less than 0.001) in the anesthetized animals regardless of the tracer employed. These studies suggest that the administration of anesthesia alone, without concomitant surgery, is associated with a decreased rate of whole body protein synthesis and increased leucine oxidation, resulting in increased leucine and protein catabolism, which may be underlying or initiating some of the protein wasting known to occur in patients undergoing surgery.     

Biological doses with template distribution patterns

Consideration of radiation dose rate effects emphasizes advantages of the template method for lateral distribution of multiple sources in treatment of laterally infiltrating gynecologic cancer, when compared to a conventional technique with colpostats. Biological doses in time dose fractionation (TDF), ret and reu units are calculated for the two treatment methods. With the template method the lateral dose (point B) is raised without significantly increasing the doses to the rectum and bladder, that is, relatively, the calculated biological doses at point A and B are more nearly equivalent and the doses to the rectum and bladder are significantly lower than the dose to point B.     

Application of image-guided surface coil P-31 MR spectroscopy to human liver, heart, and kidney

Localized phosphorus-31 magnetic resonance (MR) spectroscopy in humans has previously been accomplished with surface coils by means of depth-resolved surface coil spectroscopy or rotating frame experiments, in which the extent of tissue sampled critically depends on surface coil placement. The authors' goal was to modify the surface coil image-selected in vivo spectroscopy (ISIS) experiment to accomplish three-dimensional volume selection through application of selective pulses in the presence of B0 gradients. Advantages of ISIS include the ability to use proton images to define the volume of interest (VOI) and reduced dependence on exact positioning of the surface coil. However, rapid replication of the surface coil ISIS experiment can cause spectral contamination from signals originating outside the VOI. A modified version of the ISIS experiment was developed to alleviate contamination under conditions of rapid replication. Applications of localized P-31 MR spectroscopy for observation of high-energy phosphorus metabolites are presented in human liver, heart, and transplanted and normal kidney.