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991.
992.
993.
The patterns of radioactive estrogen metabolities in the plasma of patients with a variety of malignancies were determined after the injection of physiological amounts of 17 beta-estradiol-6,7-3H or of estrone-6,7-3H. The metabolites were separated and isolated from the plasma by the following procedures: a) alumina chromatography, b) modified Brown procedure, and c) gas liquid chromatography. This study showed that the conjugated state of the estrogens varied with the subjects's age. There was a dramatic decrease in the relative quantity of the plasma free estrogens which are converted to sulfates as the age of the patient increased. This change was noted just prior to menopause, suggesting that there are alterations in the conjugation of plasma estrogens which are detectable before clinical menopause.  相似文献   
994.
995.
The mechanism of congenital osteopetrosis in microphthalmic (mi) mice has been examined in bone organ cultures. Resorption was measured by the release of previously incorporated 45Ca in fetal long bones and newborn calvaria from mi mice and heterozygous or homozygous normal litter mates. Bones from mi mice showed a generalized resorption defect with decreased spontaneous or control resorption and failure to respond to parathyroid hormone (PTH), prostaglandin E2, 1,25 dihydroxy vitamin D3, vitamin A, or osteoclast activating factor (OAF) from human peripheral leukocytes or mouse spleen cells. Bones from heterozygotes showed a smaller response to PTH than bones from homozygous normals. Mutant bones failed to show an increase in lysosomal enzyme release in response to PTH or vitamin A, agents which increased release from bones of homozygous normals. Proline incorporation into collagenase-digestible protein was similar in cultures of normal and mutant bone and was inhibited by PTH and OAF. These results indicate that congenital osteopetrosis in mi mice is due to a generalized defect in the function and hormonal response of osteoclasts and suggests that this cell line is separate from the osteoblast cell line which shows no impairment of hormonal response.  相似文献   
996.
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998.
Why behavior analysts should study emotion: the example of anxiety   总被引:1,自引:0,他引:1  
Historically, anxiety has been a dominant subject in mainstream psychology but an incidental or even insignificant one in behavior analysis. We discuss several reasons for this discrepancy. We follow with a behavior-analytic conceptualization of anxiety that could just as easily be applied to emotion in general. Its primary points are (a) that languageable humans have an extraordinary capacity to derive relations between events and that it is a simple matter to show that neutral stimuli can acquire discriminative functions indirectly with no direct training; (b) that private events can readily acquire discriminative functions; (c) that anxiety disorders seem to occur with little apparent direct learning or that the amount of direct learning is extraordinarily out of proportion with the amount of responding; and (d) that the primary function of anxious behavior is experiential avoidance. We conclude that the most interesting aspects of anxiety disorders may occur as a function of derived rather than direct relations between public events and overt and private responses with avoidance functions. Implicit in this conclusion and explicit in the paper is the assertion that anxiety is a suitable subject for behavior-analytic study.  相似文献   
999.
A series of 1-aryl-2-dimethylaminomethyl-2-propen-1-one hydrochlorides demonstrated marked cytotoxicity towards approximately 55 human tumour cell lines from different neoplastic diseases. In general they were more potent than melphalan and displayed selective toxicity towards human leukemic cells. A representative compound, 1-phenyl-2-dimethyl-aminomethyl-2-propen-1-one hydrochloride (2a), had similar cytotoxicity as melphalan towards murine P388 and L1210 leukemic cells. In addition, 2a reduced the sizes of a number of human tumour xenografts including colon, prostatic and melanotic cancers passaged in athymic mice. Compound 2a showed excellent activity towards Ehrlich ascites carcinoma and B16F1 melanoma in mice which was enhanced using niosomes. One may conclude from the data generated that 1-aryl-2-dimethylaminomethyl-2-propen-1-one hydrochlorides are a novel series of cytotoxic and anticancer agents.  相似文献   
1000.
CONTEXT: Shigella dysenteriae type 2 is rare in the United States, and outbreaks associated with this pathogen are uncommon. OBJECTIVE: To determine the magnitude and source of an outbreak of S dysenteriae type 2. DESIGN: Retrospective cohort. SETTING: Laboratory of a large medical center. PATIENTS: Case patients were identified as laboratory workers who had diarrhea on or after October 28 and a positive stool culture or temperature greater than 37.8 degrees C. Laboratory workers with diarrhea only were probable case patients. MAIN OUTCOME MEASURES: We interviewed laboratory staff and performed identification, serotyping, and pulsed-field gel electrophoresis on isolates from case patients, implicated food, and laboratory stock culture. RESULTS: From October 29 through November 1, a total of 12 (27%) of 45 laboratory staff developed severe, acute diarrheal illness; 8 had S dysenteriae isolated from stool and 4 were hospitalized. All case patients reported having eaten muffins or doughnuts placed in the staff break room on October 29. Pulsed-field gel electrophoresis showed stool isolates from 9 case patients were indistinguishable from S dysenteriae type 2 recovered from an uneaten muffin and from the laboratory's stock strain, a portion of which was missing. CONCLUSIONS: The source of the outbreak was most likely the laboratory's stock culture, which was used to contaminate the pastries. Results of this investigation underscore the need for adequate precautions to prevent inadvertent or intentional contamination from highly pathogenic laboratory specimens.  相似文献   
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