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31.
M. Bewick C. S. Ogg V. Parsons S. A. Snowdon L. Manuel 《BMJ (Clinical research ed.)》1972,3(5825):491-494
The rosette inhibition test was used in the clinical management of organ allografts to estimate the amount of immunosuppressive drugs necessary to prevent rejection. In patients surviving more than three months renal function appeared to be better than in a similar group of patients managed without the test. It is suggested that this was due to a reduction in the number of clinical or subclinical rejection episodes. On the other hand, the test indicates that in many cases the level of immunosuppression should be much higher, and if this advice is followed the patients become increasingly exposed to the risk of infection. In other words, those patients with good renal function remained well, whereas those who might otherwise have rejected their kidney and survived had in fact died of sepsis. 相似文献
32.
33.
Studies of Raman Spectra of Water Solutions of Adenosine Tri-, Di-, and Monophosphate and Some Related Compounds
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L. Rimai T. Cole J. L. Parsons J. T. Hickmott Jr. E. B. Carew 《Biophysical journal》1969,9(3):320-329
Using a He-Ne CW laser source together with a digital photon counting system, we have obtained well resolved Raman spectra for adenosine mono-, di-, and triphosphate (AMP, ADP, ATP) in aqueous solution. Spectra of these compounds were studied as a function of pH from pH = 0.5 to 13.5 and between 550 and 1700 cm(-1). It was found possible to distinguish spectroscopically between the three phosphates over the pH range studied. A qualitative analysis of vibrational modes responsible for various spectral lines is given. Lines at about 960 and 1100 cm(-1) were found to be good indications of the degree of ionization of the terminal phosphate group. 相似文献
34.
35.
Plasma concentrations of pituitary hormones in 2,3,7,8-tetrachlorodibenzo-p-dioxin-treated male rats 总被引:1,自引:0,他引:1
R W Moore J A Parsons R C Bookstaff R E Peterson 《Journal of biochemical toxicology》1989,4(3):165-172
Experiments were conducted to test the hypothesis that acute TCDD toxicity is associated with pituitary hypofunction. Sexually mature male Sprague-Dawley rats were given graded doses of TCDD (0-100 micrograms/kg) and evaluated 7 days later. Despite pronounced hypophagia and body weight loss, plasma concentrations of growth hormone (GH), follicle-stimulating hormone (FSH), and luteinizing hormone (LH) were not significantly affected by any dose of TCDD. Only prolactin (PRL) concentrations were reduced, while, as previously reported, thyroid-stimulating hormone concentrations were elevated. Also, plasma LH, PRL, and adrenocorticotropic hormone (ACTH) concentrations were not significantly affected 1, 2, 3, 4, 5, or 7 days after a single dose of TCDD (50 micrograms/kg). We conclude that (1) pituitary hypofunction is not a major cause of the initial stages of acute TCDD toxicity, (2) growth retardation in TCDD-treated rats is not the result of a deficiency of GH, (3) alterations in plasma corticosterone concentrations are due to altered responsiveness of the adrenal to ACTH stimulation rather than to changes in plasma ACTH concentrations, and (4) that impaired spermatogenesis is not associated with a decrease in plasma FSH concentrations. In addition, the lack of a consistent effect on plasma PRL concentrations suggests that alterations in plasma PRL concentrations do not play a critical role in the toxicity of TCDD. Finally, because TCDD treatment causes a serious androgenic deficiency without increasing the rates at which androgens are catabolized or excreted, the fact that plasma LH concentrations were unaffected indicates that TCDD treatment must reduce the responsiveness of the testis to LH stimulation.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
36.
M McEwan P G Parsons D J Moss S Burrows D Stenzel C J Bishop G M Strutton 《Pigment cell research / sponsored by the European Society for Pigment Cell Research and the International Pigment Cell Society》1989,2(1):1-7
BALB/c mice were immunized with tyrosinase, partially purified in two stages from a human melanoma cell line. A hybridoma was obtained which produced monoclonal antibody (MoAb 1C11) reactive with 8/10 melanoma cell lines and 10/10 primary cultures of human melanocytes, neval cells, and melanomas. Immunoreactivity correlated to a certain extent with tyrosinase activity but not with melanin content. No crossreactivity was obtained with neuroblastoma, medulloblastoma, fibroblasts, keratinocytes, lymphoid cells, or murine melanomas. Purification of the antigen directly from cell lysates with a MoAb 1C11 CNBr-Sepharose affinity column gave a green-brown protein of 56 kDa with no detectable tyrosinase activity. This protein was therefore different from 60 kDa active tyrosinase, identified by enzyme activity and Western blotting with a MoAb derived previously (MoAb 5C12). Unlike 5C12, 1C11 reactivity was not destroyed by pretreatment of the antigen with periodate. Immunogold labelling showed that the 1C11-reactive antigen was associated with melanosomes, and there was close correlation between 5C12 and 1C11 reactivity in resistance to trypsin and in staining various melanocytic cell populations. MoAb 1C11 may therefore recognise a polypeptide epitope in a molecule closely linked to melanin biosynthesis. 相似文献
37.
R W Moni P G Parsons R J Quinn R J Willis 《Biochemical and biophysical research communications》1992,182(1):115-120
The marine natural product, halistanol trisulfate, has a relatively low critical micelle concentration of 0.001% m/v (14.5 microM) and strong hemolytic potency with an EC50 of 0.00046% m/v (6.67 microM). As expected of a detergent, it inhibits the growth of gram-positive but not gram-negative bacteria. The hemolytic activity of halistanol trisulfate and other detergents has been shown to correlate with critical micelle concentration. This correlation may have important implications in the mechanism of membranolytic bioactivity. 相似文献
38.
The relationship of the acetylcholine transporter-vesamicol receptor (AcChT-VR) to proteoglycan in Torpedo electric organ synaptic vesicles was investigated. The cholate-solubilized VR was immunoprecipitated by a monoclonal antibody directed against the SV1 epitope located in the glycosaminoglycan portion of the proteoglycan. AcChT that was photoaffinity-labeled with a tritiated high-affinity analogue of AcCh [cyclohexylmethyl cis-N-(4-azidophenacyl)-N-methylisonipecotate] and then denatured in sodium dodecyl sulfate also immunoprecipitated. The labeled AcChT exhibited a M(r) range of 100,000-200,000. Proteoglycan did not engage in detectable nonspecific reversible aggregation that might mask the presence of another subunit during sodium dodecyl sulfate-polyacrylamide gel electrophoresis. In vesicles permeabilized with cholate, the enzymes keratanase and testicular hyaluronidase inactivated binding of vesamicol and destroyed the SV1 epitope without detectable proteolysis. Other glycosaminoglycan-degrading enzymes were without effect. The results demonstrate that the AcChT-VR and proteoglycan are very strongly linked and that glycosaminoglycan-like polysaccharide controls the conformation of the VR. The unexpected linkage to proteoglycan suggests that AcChT-VR in intact terminals might communicate with extracellular matrix and participate in stabilization and operation of the synapse. 相似文献
39.
Jeff Reeve Lorraine H. Kligman Robert Anderson 《Applied microbiology and biotechnology》1990,33(2):161-166
Summary Isolated lipids from Deinococcus radiodurans were reconstituted at final concentrations of 1 mg/ml into dioleoyl phosphatidyl choline (DOPC) vesicles and assayed for the ability to protect cells of Escherichia coli against killing by UV light (254 nm). Values of D37 (UV dose required to reduce the number of surviving cells to 37% of the original number) were calculated from killing curves. E. coli was afforded the greatest protection with an individual lipid, identified as vitamin MK8 (D37=310 J//m2, compared to D37=67 J/m2 for E. coli irradiated in the presence of DOPC alone). Liposome-mediated protection was dependent on UV254 absorbance and not on turbidity-related light-scattering. BOth vitamin MK8 from D. radiodurans and vitamin K1, which is available commercially, showed a similar degree of UV254-protection for E. coli. The UV-protective properties of vitamin K1 were also investigated on mammalian cells in comparison with other natural lipids and known sunscreens. Survival curves were obtained for mouse fibroblast (L) cells irradiated at UV254 in the absence or presence of DOPC liposomes into which were incorporated various natural lipids or standard sunscreen ingredients, all at final concentrations of 1 mg/ml. Experimentally determined values of D37 were as follows: Vitamin K1, 73 J/m2; \-carotene, 44 J/m2; -tocopherol, 20 J/m2; sulisobenzone, 156 J/m2; p-aminobenzoic acid (PABA), 113 J/m2; benzophenone, 80 J/m2; oxybenzone, 61 J/m2 and DOPC alone. 23 J/m2. Vitamin K1, the most protective lipid tested, was also compared with PABA and oxybenzone (all at concentrations of 20 mg/ml; applied topicall) for its ability to protec Skh-hairless mice from UV254-induced erythema, yielding a UV254 protection factor of 3.5. In addition, vitamin K1 (at 100 mg/ml) was able to provide hairless mice with a small degree of UVB protection, as indicated by an experimentally determined Solar Protection Factor of 1.5–2.0. Although it is concluded that vitamin K is not likely to account for the extraordinarily high degree of UV-resistance of D. radiodurans, vitamin K does show characteristics worthy of its consideration as a UV-screening agent.
Offprint requests to: R. Anderson 相似文献
40.
T. C. Hsu Edward J. Shillitoe Lorraine M. Cherry Qi Lin Stimson P. Schantz Cynthia Furlong 《In vitro cellular & developmental biology. Plant》1990,26(1):80-84
Summary Forty lymphoblastoid (lymphoid) lines were established from 42 volunteer blood donors, including healthy individuals and patients
with head and neck carcinomas. Each peripheral blood sample was split into two portions, one for the establishment of a lymphoid
line and the other for short-term culture, which was used to estimate bleomycin sensitivity by cytogenetic procedures. Twenty
lymphoid lines were selected at random to compare bleomycin sensitivity with data obtained from short-term lymphocyte cultures.
In each set, bleomycin sensitivity of lymphoid cells was similar to that of the lymphocytes. The lymphoid lines, which can
be propagated for an unlimited supply of relatively homogeneous cellular material, will be useful for a variety of future
investigations.
This investigation was supported by grants from the John S. Dunn Foundation, Houston, TX, the Esther Knispel Fund administered
by The University of Texas M. D. Anderson Cancer Center, Houston, TX, and Department of Health and Human Services PHS grant
DE 07007. 相似文献