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41.
H Nakashima Y Hirata M Uchihashi T Fujita H Taniguchi S Baba S Matsukura 《Hormones et métabolisme》1985,17(4):205-208
Release of plasma ACTH- and beta-endorphin (beta-EP)-like immunoreactivity (LI) was studied in vivo in a patient with an ectopic ACTH-producing malignant thymoma. Administration of lysin vasopressin stimulated concomitant release of plasma ACTH- and beta-EP-LI. Administration of cyproheptadine, naloxone, and somatostatin significantly suppressed plasma levels of ACTH- and beta-EP-LI, while saline infusion did not. Gel exclusion chromatography of the plasma extracts revealed that ACTH-LI consisted of two components, large and small molecular weight form, while beta-EP-LI consisted of three components, large molecular weight, beta-lipotropin-, and beta-EP-sized form; each of these components was incompletely suppressed by somatostatin infusion. It is suggested that certain tumors may have acquired aberrant multiple receptors during malignant transformation which may lead to the paradoxical hormone response as demonstrated in this case. 相似文献
42.
43.
N Taniguchi K Yanagisawa A Makita M Naiki 《The Journal of biological chemistry》1985,260(8):4908-4913
The enzyme which catalyzes the transfer of galactose from UDP-galactose to lactosylceramide (LacCer) was obtained in a 32,000-fold purified and apparently homogeneous form from rat liver by a procedure involving affinity chromatography on UDP-hexanolamine-Sepharose and LacCer-Sepharose. The enzyme is composed of two nonidentical subunits whose apparent molecular weights are 65,000 and 22,000. Methylation and hydrolysis of the product formed by incubation of the enzyme with UDP-galactose and [3H]LacCer yielded 2,3,6-tri-O-methyl-[3H]galactose, indicating that a galactose residue was introduced to position C-4 of the terminal galactose of the LacCer. The product also specifically reacted with monoclonal antibody directed to globotriaosylceramide (Gal alpha 1-4Gal beta 1-4Glc beta 1-1Cer). This indicates that the purified enzyme is exclusively alpha 1-4-galactosyltransferase. Studies on substrate specificity indicate that the purified enzyme is highly specific for the synthesis of GbOse3Cer and is clearly distinct from the enzymes responsible for the formation of iGbOse3Cer (Gal alpha 1-3Gal beta 1-4Glc-Cer) and blood group-B substance, which possess alpha 1-3 galactosidic linkages at the nonreducing termini. The enzyme is also distinct from the alpha 1-4-galactosyltransferase which catalyzes the formation of galabiaosylceramide (Gal alpha 1-4Gal beta 1-1Cer) and IV4Gal-nLacOse4 (P1 antigen). These studies represent the first report of the properties of a highly purified alpha-galactosyltransferase catalyzing the transfer of sugar residues to glycolipids. 相似文献
44.
45.
M Tagawa T Tokuhisa K Ono M Taniguchi L A Herzenberg L A Herzenberg 《Cellular immunology》1984,86(2):327-336
Sequential immunization with a carrier molecule and a new epitope (hapten) conjugated to the carrier (carrier/hapten-carrier immunization) induces specific suppression for IgG antibody production to the new epitope (hapten) on the carrier. Once induced, this "epitope-specific" suppression persists and specifically suppresses subsequent in vivo IgG antibody responses to the hapten presented on the same or on an unrelated carrier molecule. In vitro studies presented here characterize the surface markers and specificity of suppressor T cells generated in carrier/hapten-carrier-immunized animals. Thus we show (1) that spleen cells from these donors suppress in vitro IgG anti-hapten antibody production by cocultured hapten-primed spleen cells; (2) that some but not all of the suppressor cells carry surface Lyt-2; (3) that at least some of the suppressor cells have receptors for the inducing hapten (DNP); and (4) that, unlike the suppression obtained in vivo, the in vitro suppression extends to IgG responses to unrelated carrier protein epitopes presented in association with the inducing hapten. 相似文献
46.
Interferon-gamma can augment expression ability of HLA-DR antigens on pokeweed mitogen-stimulated human T lymphocytes 总被引:2,自引:0,他引:2
The effect of natural interferon (IFN)-gamma on HLA-DR molecule expression of pokeweed mitogen (PWM)-stimulated T cells from cord blood and adult peripheral blood was assessed by direct immunofluorescence with fluorescein-labeled monoclonal anti-HLA-DR antibody on a flow cytometer. Although cord blood T cells showed only weak expression of HLA-DR antigens on PWM stimulation, IFN-gamma could enhance HLA-DR expression of PWM-stimulated cord blood T cells to levels comparable to those of adult ones. A similar, but slight, increase in HLA-DR expression was inducible in PWM-stimulated adult T cells by the addition of IFN-gamma, but at higher doses. This increased expression of HLA-Dr antigens on PWM-stimulated T cells was almost completely abolished by both acid treatment of IFN-gamma and neutralization of IFN-gamma with specific antiserum. In contrast to IFN-gamma, neither recombinant IFN-alpha nor IFN-beta showed any effect on HLA-DR expression of PWM-stimulated T cells. These results suggested a possible function of IFN-gamma that might modulate HLA-DR expression ability of T cells in their activation process. 相似文献
47.
Similarities between rat liver mitochondrial and cytosolic glutathione reductases and their apoenzyme accumulation in riboflavin deficiency 总被引:1,自引:0,他引:1
Glutathione reductase has been purified 5,500-fold from rat liver mitochondrial matrix in a yield of 30%. The mitochondrial enzyme was immunochemically indistinguishable from that of the cytosol and the subunit molecular weight was apparently similar to that of the cytosolic enzyme, that is, 50,000 daltons. The optimum pH and kinetic properties investigated were not significantly different from those of the cytosolic enzyme. When rats were fed a riboflavin-deficient diet, the enzyme activity in the mitochondria decreased to a greater extent than that in the cytosol, and greater accumulation of apo-enzyme in the former than that in the latter was confirmed by the amount of immunoprecipitable protein, activation by FAD addition in vitro, and the enzyme activity recovery after injection of riboflavin, into riboflavin-deficient rats. 相似文献
48.
49.
Ikuo Taniguchi Hideto Niwa Donald Wong Nobuo Suga 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1986,159(3):331-337
Summary For echolocation, the mustached bat,Pteronotus parnellii rubiginosus, emits orientation sounds (pulses) and listens to echoes. Each pulse is made up of 8 components, of which 4 are constant frequencies (CF1–4) and 4 are frequency-modulated (FM1–4). Target-range information, conveyed by the time delay of the echo FM from the pulse FM, is processed in this species by specialized neurons in a part of the auditory cortex known as the FM-FM area. These cortical neurons are responsive to pulse-echo pairs at specific echo delays (Fig. 1). The essential components in the sound pair include the pulse FM1 followed by an echo FMn (n=2, 3 or 4). Downward sweeping FM1-FMn sounds that are similar to those the animal naturally hears during echolocation are the most effective in evoking facilitative responses. Most FM-FM neurons, however, still exhibit facilitative responses to stimulus pairs consisting of upward sweeping FM sounds and/or pure tones at frequencies found in FM sweeps (Figs. 2 and 3). The magnitude of facilitation is altered by changes in echo rather than pulse amplitude (Figs. 5 and 6). Neurons characterized by shorter best delays (or echoes from closer targets) do not require larger best echo amplitudes for facilitation.Abbreviations
CF
constant frequency
-
FM
frequency modulation
-
H
n
CF — FM harmonics of the mustached bat biosonar signal
-
CF
n
CF components of the harmonics
-
FM
n
FM components of the harmonics
-
PCF
n
pulse CFn
-
ECF
n
echo CFn
-
PFM
n
pulse FMn
-
EFM
n
echo FMn
-
PH
n
pulse Hn
-
EH
n
echo Hn
-
BA
best amplitude for facilitation
-
BD
best delay for facilitation
-
PST
peri-stimulus-time
-
PSTC
peri-stimulus-time-cumulative
-
dB SPL
dB re 20 Pa 相似文献
50.