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1.
Alex N. Bullock Julia Henckel Brian S. DeDecker Christopher M. Johnson Penka V. Nikolova Mark R. Proctor David P. Lane Alan R. Fersht 《Proceedings of the National Academy of Sciences of the United States of America》1997,94(26):14338-14342
Some 50% of human cancers are associated with mutations in the core domain of the tumor suppressor p53. Many mutations are thought just to destabilize the protein. To assess this and the possibility of rescue, we have set up a system to analyze the stability of the core domain and its mutants. The use of differential scanning calorimetry or spectroscopy to measure its melting temperature leads to irreversible denaturation and aggregation and so is useful as only a qualitative guide to stability. There are excellent two-state denaturation curves on the addition of urea that may be analyzed quantitatively. One Zn2+ ion remains tightly bound in the holo-form of p53 throughout the denaturation curve. The stability of wild type is 6.0 kcal (1 kcal = 4.18 kJ)/mol at 25°C and 9.8 kcal/mol at 10°C. The oncogenic mutants R175H, C242S, R248Q, R249S, and R273H are destabilized by 3.0, 2.9, 1.9, 1.9, and 0.4 kcal/mol, respectively. Under certain denaturing conditions, the wild-type domain forms an aggregate that is relatively highly fluorescent at 340 nm on excitation at 280 nm. The destabilized mutants give this fluorescence under milder denaturation conditions. 相似文献
2.
This study deals with the influence of peroperative ligament tension on total tibial rotation at different knee flexion angles. Fourteen human cadaver knees with a mean age of 56 years (range 42–84 years) were examined. The cadaver knees were subjected to internal/external (i/e) rotational torque of 6 Nm, at 10, 30, 50, 70 and 90 deg of knee flexion. The mean total i/e rotation with the anterior cruciate ligament (ACL) intact at 10 deg of knee flexion was 30.4 deg and after removing the ACL, 33.1 deg. At 10 and 30 deg of knee flexion, the increase in i/e rotation was significant, while there was no significant difference in mean values at greater knee flexion. Ligament reconstruction with a tension of 5 N at 30 deg of knee flexion using either the over the top or through the femoral condyle reconstructive procedure restored normal tibial rotation. With increased graft tension the knee motion was increasingly restricted at low angles of knee flexion. Our results indicate that the ACL does play a role in limiting axial rotation, and even minor tensioning forces introduced in any of the two ACL reconstructions used produced restricted knee motion. 相似文献
3.
4.
Ultrastructure of the early human implantation in vitro 总被引:1,自引:1,他引:1
Lindenberg Svend; Hyttel Poul; Lenz Sunzan; Holmes Poul V. 《Human reproduction (Oxford, England)》1986,1(8):533-538
Four hatched human blastocysts obtained after in-vitro fertilizationand development were placed on monolayer cell cultures of humanendometrial epithelium, and subsequently examined by transmissionelectron microscopy. All four blastocysts became adherent tothe monolayer and three implanted and exhibited outgrowth oftheir trophoblastic cells. During implantation the blastocystsdifferentiated into mural and polar trophoblastic cells, andembryonic cells including endodermal cells. The endometrialcells were displaced and stacked into a multilayer at the peripheryof the implantation sites, allowing the trophoblastic cellsto come in contact with the culture dish. The endometrial cellsdisplayed local exo- or endo-cytosis where they contacted thetrophoblastic cells. The trophoblastic cells were not observedto be phagocytosing endometrial cells. These observations suggestthat human blastocysts portray an intrusive type of implantationduring the initial stages. 相似文献
5.
Hvidtjørn D Grove J Schendel D Vaeth M Ernst E Nielsen L Thorsen P 《Human reproduction (Oxford, England)》2005,20(9):2550-2551
BACKGROUND: In a Danish population-based cohort study assessing the risk of cerebral palsy in children born after IVF, we made some interesting observations regarding 'vanishing co-embryos'. METHODS and RESULTS: All live-born children born in Denmark from 1 January 1995 to 31 December 2000 were included in this analysis. The children conceived by IVF/ICSI (9444) were identified through the IVF Register, the children conceived without IVF/ICSI (395 025) were identified through The Danish Medical Birth Register. Main outcome measure was the incidence of cerebral palsy. Within the IVF/ICSI children we found indications of an increased risk of cerebral palsy in those children resulting from pregnancies, where the number of embryos transferred was higher than the number of children born. CONCLUSIONS: The association between vanishing embryo syndrome and incidence of cerebral palsy following IVF requires further investigation in larger, adequately powered, studies. 相似文献
6.
Cauci S Thorsen P Schendel DE Bremmelgaard A Quadrifoglio F Guaschino S 《Journal of clinical microbiology》2003,41(1):435-438
A nested case-control study of low birth weight and preterm delivery was performed with singleton women. Immunoglobulin A (IgA) against the Gardnerella vaginalis hemolysin (anti-Gvh IgA) and sialidase and prolidase activities were determined in vaginal fluid at 17 weeks of gestation. Sialidase positivity and bacterial vaginosis with high prolidase activity were associated with 2- and 11-fold increased risks for low birth weight, respectively. No woman with bacterial vaginosis plus a strong anti-Gvh IgA response had an adverse outcome. 相似文献
7.
A brief introduction to the Danish Cytogenetic Central Register (DCCR) is given, and possibilities, principles and problems concerning the establishment and maintenance of a national cytogenetic register are presented.
Various data carrier media for registers in general are discussed, of which the magnetic disc is considered most appropriate. General principles for programs capable of performing insertions, deletions and other modifications in the data base are outlined as well as the principles for the programs in the DCCR.
The individual records should preferably be identified by aid of a central person registration number (CPR) rather than by name. The data should be stored and sorted by this identification in order to facilitate retrieval of a desired record. The structure of the records is discussed with regard to prevention of the occurrence of certain errors as well as the optimization of processing.
Flexibility and economy of space are achieved by using programs able to handle records of unequal length, and problems occurring in connection with this are discussed. The question of how to protect sensitive data is dealt with, and two different methods used in the DCCR are outlined. Programs capable of analyzing karyotypes with the purpose of recognizing various cytogenetic syndromes have been developed for use in the DCCR. Various examples of computing times of typical program runs are presented. 相似文献
Various data carrier media for registers in general are discussed, of which the magnetic disc is considered most appropriate. General principles for programs capable of performing insertions, deletions and other modifications in the data base are outlined as well as the principles for the programs in the DCCR.
The individual records should preferably be identified by aid of a central person registration number (CPR) rather than by name. The data should be stored and sorted by this identification in order to facilitate retrieval of a desired record. The structure of the records is discussed with regard to prevention of the occurrence of certain errors as well as the optimization of processing.
Flexibility and economy of space are achieved by using programs able to handle records of unequal length, and problems occurring in connection with this are discussed. The question of how to protect sensitive data is dealt with, and two different methods used in the DCCR are outlined. Programs capable of analyzing karyotypes with the purpose of recognizing various cytogenetic syndromes have been developed for use in the DCCR. Various examples of computing times of typical program runs are presented. 相似文献
8.
Stable hybridoma cell lines secreting antibodies specific for the apple chlorotic leaf spot virus (CLSV) were produced by fusing spleen cells of a Biozzi mouse immunized with CLSV P863 strain, with the non-secretory P3 X63 Ag8.653 myeloma cell line. Two hybridoma clones producing monoclonal antibodies of the IgG1 subclass were obtained. These monoclonal antibodies were used for virus detection by enzyme-linked immunosorbent assay (ELISA). In contrast to polyclonal antisera to CLSV, which always contain some antibodies to host components, monoclonal antibodies are highly specific for the virus. It was thus possible to develop a detection assay which is more sensitive and specific than the assays using polyclonal antibodies. Using monoclonal antibodies, it was possible to detect less than 0.1 ng/ml of purified virus. In addition, these two monoclonal antibodies recognize 17 strains or isolates maintained in our laboratory and representing most of the known CLSV strains. 相似文献
9.
Uffe A. Brodthagen Knud NØrregaard Hansen Jens Bjerre Knudsen Robert Jordal Ole Kristensen Poul -Erik Paulev 《European journal of applied physiology》1985,53(4):334-338
Summary 20 male elite long distance runners were compared to a control group of blood donors to determine the effect of training on red blood cells. The acute effects of exercise on red cells were investigated in 11 of the runners following a race of 15–30 km. The runners had elevated resting values of red cell 2,3-DPG (P<0.05) and mean cell volume (P<0.01); blood Hb and ATP were not different from concentrations in the control group. The red cell status of the athletes may be explained by an increased proportion of young erythrocytes in runners. No statistically significant changes in red cell 2,3-DPG, ATP, mean cell volume or blood Hb were found post exercise. 相似文献