A constrained tracking algorithm to optimize plug patterns in multiple isocenter gamma knife radiosurgery planning

We developed a source blocking optimization algorithm for Gamma Knife radiosurgery, which is based on tracking individual source contributions to arbitrarily shaped target and critical structure volumes. A scalar objective function and a direct search algorithm were used to produce near real-time calculation results. The algorithm allows the user to set and vary the total number of plugs for each shot to limit the total beam-on time. We implemented and tested the algorithm for several multiple-isocenter Gamma Knife cases. It was found that the use of limited number of plugs significantly lowered the integral dose to the critical structures such as an optical chiasm in pituitary adenoma cases. The main effect of the source blocking is the faster dose falloff in the junction area between the target and the critical structure. In summary, we demonstrated a useful source-plugging algorithm for improving complex multi-isocenter Gamma Knife treatment planning cases.     

API0134对大鼠血浆和血小板血栓素B2生成与血小板聚集的影响

用放射免疫分析法和比浊法测定ＰＡＩ０１３４对大鼠血浆血栓素Ｂ２浓度，血小板ＴＸＢ２生成血小板聚集的影响。静脉注射ＡＰＩ０１３４７０ｍｇ或１００ｍｇ．ｋｇ显著降低血浆ＴＸＢ２浓度，其降低２率分别为３８．８％和５１．６％，ＡＰＩ０１３４明显抑制ＡＤＰ诱导的大鼠血小板聚集和ＴＸＢ２生成，抑制率分别为２７．８％，３９．５％，和４１．４％，５３．６％，两抑制率间呈显著正相关。     

Ultrastructure of Amelanotic Melanocytes from Human Hair Follicles

Objective: To investigate the ultra structure of amelanotic melanocytes (AMMC). Methods: The hair follicles obtained from normal human scalp by 0.50% collagenase type V treatment were washed with 0.1mol/L phosphate buffer salt (PBS). Hair-follicle cell suspensions were prepared by trypsin treatment and cultured in melanocyte medium. Remaining keratinocytes were removed by differential trypsinization. 100μg/ml geneticin was used to eliminate the contaminating fibroblasts. At third passage, the cells were trypsinized, and then washed in phosphate-buffered saline and processed for transmission electron microscopy. Results: Under transmission electron microscope, the cultured cells showed round or oval shape, with single large nuclear and the karyotheca were double deck. There were obvious euchromosome within the nucleus, and sparse heterochromosome. There were various organelles in the cytoplasm, including plentiful melanosomes with nearly similar size, mitochondria, rough endoplasmic reticule (RER) and ribosome. The electron density granules in most of the melanosomes disposed along concentric circularities. Golgi apparatus in the cells was inconspicuous. Conclusion: The ultra structure of AMMC from human hair follicles is different from that of epidermal melanocytes, and these characteristics determine the functional immature of AMMC.     

Human heat shock protein 60 (409-424) fragment is recognized by serum antibodies of patients with acute coronary syndromes.

Acute coronary syndromes (ACS), including unstable angina (UA) and acute myocardial infarction (MI), are clinical manifestations of a progressive atherosclerotic process. Antibodies (Ab) to heat shock proteins (hsp) have been reported to be associated with atherosclerosis. Blood samples from 35 patients with ACS and 20 healthy volunteers were tested for Ab to human hsp60 by an enzyme-linked immunosorbent assay (ELISA). Levels of specific serum Ab against hsp60 were significantly elevated in patients with ACS when compared to clinically healthy subjects. To determine the antigenic determinants recognized by these Ab, antibody binding to seven peptides, selected from the hydrophilic and acrophilic regions of the human hsp60 molecule, was assessed. Despite the individual variation in the immune response among patients, one immunodominant region was revealed corresponding to the hsp60 (409-424) peptide. The identification of this epitope may be important for understanding the function of this protein in the atherosclerotic process.     

Clear cell chondrosarcoma: case report and ultrastructural study

A case of clear cell chondrosarcoma in a Chinese patient is described. The clear cells showed strongly positive S-100 protein immunoreactivity. Ultrastructurally 2 types of chondroid cells were demonstrated. One type appeared more primitive with abundant electron-lucent cytoplasm and sparse organelles. The other type of cell was more differentiated with presence of microvilli and numerous dilated cisternae of endoplasmic reticulum. Previous ultrastructural studies on these lesions were reviewed and compared with the present findings.     

Effects of social rearing conditions on conditioned suppression in rats

Twenty-two rats were reared in standard conditions during the first two months of their life. Then the animals were divided into two groups exposed to different rearing conditions. Twelve animals (Group SO) were housed socially, six animals per cage, and for three weeks they were subjected to sensory stimulation in an enriched environment. The other ten subjects were kept individually (Group IN); one rat per mesh cage, in conditions of relatively impoverished sensory stimulation. In both groups the training of the conditioned emotional response (CER) was performed when animals were three months old. In contrast to IN subjects, the rats subjected to permanent social contacts and reared in the enriched environment (Group SO) revealed almost equally low instrumental response rates in trials with the conditioned stimulus (CS) paired with nociceptive foot-shock (US), and in periods when no CS and/or US were applied. The results suggested that early exposure to an enriched environment caused a later decrease of the animals' capability to differentiate between the aversive CS and cues of the experimental context. This cognitive impairment was probably a secondary effect of fear generalized to the entire experimental situation.