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91.
We have further characterized osteoclast activating factor (OAF) using a bioassay for bone resorption which utilizes the release of previously incorporated (45)Ca from fetal rat long bones in organ culture. When supernatant media from activated leukocyte cultures were concentrated on Amicon PM10 membranes (assigned molecular weight cutoff 10,000 daltons) and chromatographed on Sephadex G-50 columns, the bone-resorbing activity eluted between the molecular weight markers chymotrypsinogen (25,000 daltons) and cytochrome c (12,500 daltons). This peak of biological activity has been called big OAF. When filtrates from the PM10 membranes were concentrated on Amicon UM2 membranes (assigned molecular weight cutoff 1,000 daltons) and chromatographed on Sephadex G-50 columns, some of the biological activity eluted between the molecular weight markers chymotrypsinogen and cytochrome c (big OAF), but there was a separate peak of biological activity which eluted with [(3)H]proline (140 daltons). This second peak has been called little OAF. Little OAF was eluted from Bio-Gel P6 columns between the molecular weight markers calcitonin (approximately 3,500 daltons) and vitamin B(12) (1,330 daltons), but was retained by Spectrapor dialysis tubing (nominal molecular weight cutoff 3,500 daltons). Big OAF was converted to little OAF by equilibration in 1 M NaCl or 2 M urea. Little OAF was self-associated back to big OAF by equilibration in buffers of low ionic strength (Tris-HCl 10-50 mM). Little OAF was extracted into the organic phase in ethyl acetate after acidification of the sample to pH 3.5. The biological activity remained in the aqueous phase after ethyl acetate extraction at pH 7.5-8.4. Little OAF has been purified more than 6,000-fold compared with the original material so that bone-resorbing activity is maximal in a sample with a protein concentration of 80 ng/ml.  相似文献   
92.
Simultaneous measurement of cardiac output distribution with 86Rubidium and 57Cobalt-tagged microspheres in rats implanted with liver tumors by intraportal injection of sarcoma cells enables quantitation of arterial and portal tumor circulation. The portal circulation was found to be increased in small tumors as compared to the liver, but as the tumor grew there was a decrease in the portal tumor circulation. When the tumor growth became massive even the total liver circulation was reduced, as measured with 133Xenon wash-out. All the tumors had increased arterial circulation. This arterial hyperperfusion was changed into ischemia when the liver artery was occluded through embolization with degradable microspheres.  相似文献   
93.
The effects of age, sex, and neutering on the prevalence of canine intestinal parasitism were evaluated by fecal examination of 1,468 pet dogs admitted to the University of Missouri Veterinary Teaching Hospital during 1975. Evidence of hookworm infection was encountered in 35.8% of the dogs examined, whipworms in 18.5%, ascarids in 17.9%, tapeworms in 5.2%, and coccidia in 4.5%. Evidence of intestinal parasitism was not detected in 653 (44.4%) dogs. Whipworm infections were detected less often in young dogs than in older ones, whereas ascarid and coccidial infections were more prevalent in pups that in mature dogs. In dogs more than 6 months old, hookworm infections were the most common parasitism. Tapeworm infections were diagnosed sporadically in all age groups. For most of these parasites, castrated males and spayed females had decreased prevalence of infection, compared with their respective intact counterparts. There were significant (P less than 0.05) differences in the prevalence of both ascarid and hookworm infections between intact and spayed female dogs. Also, there were significant (P less than 0.001) differences between age categories for all parasites observed. Overall, parasitism tended to decrease with age.  相似文献   
94.
Incubation of normal rat cortical or brain stem tissue with 3H-NE or 3H-5-HT and subsequent exposure to amphetamine produced a concentration-related release of the transmitters from tissue stores into the incubation media. Although pretreatment with the catecholamine neurotoxin in 6-hydroxydopamine (6-OHDA) reduced the retention of 3H-NE in both of these tissues, the proportion of 3H-NE released by amphetamine was attenuated only in cortical tissue. Pretreatment with the serotonergic neurotoxin, 5,6-dihydroxytryptamine (5,6-DHT) had no effect on the retention or release of 3H-NE in cortical or brain stem tissue. Pretreatment with 5,6-DHT reduced the retention of 3H-5-HT in the cortex and brain stem, but the release of 3H-5-HT was significantly attenuated only in the latter tissue. 6-OHDA pretreatment increased the retention and proportion of cortical 3H-5-HT released by amphetamine but reduced the release of brain stem 3H-5-HT in the absence of an effect on retention. It appears that the in vitro release of 3H-NE from the cerebral cortex occurs primarily from catecholamine and not serotonergic neurons whereas the cortical release of 3H-5-HT is not an event specific to serotonergic nerve terminals. The release of 3H-5-HT from brain stem does not appear to be restricted to the serotonergic cell bodies since its release was attenuated by 5,6-DHT and 6-OHDA.  相似文献   
95.
Cryonecrosis of the upper lobe of the lung and bronchi was safely inudced in healthy dogs by application of the cryoprobe to serosal surfaces or, through a bronchotomy, to the mucosal surfaces under direct vision. Seven days after cryosurgery, hyperemia of the bronchus was seen. By 14 days the bronchus at the target site was covered with cuboidal epithelium. Reappearance of normal ciliated epithelium occurred by 180 days after cryosurgery. Cartilage remained intact, and there was no evidence of formation of a stricture or other gross alteration of bronchial architecture. In the lung there was coagulation necrosis; and by 14 days after cryosurgery, there was fibrosis in the target area. There were no complications of the pleural space. Cryosurgery of tissues at the margins of the bronchotomy does not impair healing. Cryosurgery may reduce the necessity for extensive surgery in selected patients with bronchopulmonary tumors, including those inaccessible to the rigid bronchoscope. Clinically, eight patients with recurrent bronchogenic tumors have received palliation by transbronchoscopic cryosurgery.  相似文献   
96.
A vital function of the emergency physician is separating patients with chest pain who require intensive immediate treatment from those who require minimal care. The care of 701 patients presenting with chest pain in two Baltimore hospitals was evaluated using medical record data and follow-up questionnaires to discharged patients. Twenty per cent were admitted. There was a significant difference between the two hospitals in admission rates. Thirty-five per cent of the discharged patients felt no better two weeks after emergency department discharge. Plans for further research include a study to clarify the difference in admission rates and the characteristics of individuals who remained symptomatic at two weeks.  相似文献   
97.
Intergeneric transfer of genes involved in the Rhizobium-legume symbiosis   总被引:2,自引:0,他引:2  
Genes that seem to be involved in the initial steps of infection of a legume by Rhizobium have been transferred, by transformation, to mutant strains of Azotobacter vinelandii that are unable to fix nitrogen. These genes code for a surface antigen that binds specifically to a protein from the host plant.  相似文献   
98.
This study provides a map of variations of families and some of the core relationships between types of family and the mental health of children. Family types in a poor, black urban community were defined in terms of the adults present at home. The resulting taxonomy is based on two populations: half of the community's 1964 first-grade children and families and the entire 1966 first-grade children and families. Eighty-six family types were found, falling into ten major classes. Family type was found to be strongly related over time to the child's social adaptational status (SAS) and his or her psychological well-being. The results suggest that (1) mother alone families entail the highest risk in terms of social maladaptation and psychological well-being of the child; (2) the presence of certain second adults has important ameliorative functions--mother/grandmother families being nearly as effective as mother/father families, with mother/stepfather families similar to mother alone in regard to risk; and (3) the absence of the father was less important than the aloneness of the mother in relation to risk.  相似文献   
99.
An abnormal accumulation of radionuclide was identified within the right juxtadiaphragmatic and juxtahepatic spaces during gallium-67 citrate scintigraphy in a post-pyeloplasty patient. Its mode of presentation, the recent pyeloplasty and the known biologic distribution of gallium suggested that it represented gallium-67 concentration within a postoperatively created urinoma. Diagnosis was confirmed by excretory urography and laparotomy.  相似文献   
100.
The electronic structure of tetragonal (RC(N))m(TB)2, m=1–3, compounds, with R= Y,Lu,La, T=Ni,Pt is studied. Total and partial densities of states N(E) are calculated and compared with orbital resolved x-ray absorption data. Special attention is paid to the structure of N(E) near the Fermi-level and its consequences for thermodynamic properties in the superconducting and the normal states. A medium el-ph coupling constant 0.5 1.2 is found. There is no simple correlation between N(0) and T c . The analysis of the upper critical field reveals the presence of at least two groups of electrons with quite different Fermi velocities v F in accord with dHvA data, and with calculated distributions of v F around the Fermi surface  相似文献   
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