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1.
1. Circulating concentrations of iodothyronines, luteinizing hormone(LH), estradiol(E2), progesterone and corticosterone were measured in hens before, during, and after a forced molt induced by fasting. 2. Corticosterone increased at the onset of molt, peaked at the maximal molt and returned to pre- and post-molt levels. LH, E2 and progesterone declined during the molt, and the decline was coincident with the cessation of egg production. 3. Thyroxine(T4), triiodothyronine (T3) and reverse triiodothyronine(rT3) increased during the molt. The increases of T4 and T3 were not abolished even if the forced molt was conducted in mild weather.  相似文献   
2.
The receptor for atrial natriuretic peptide (ANP) was purified to apparent homogeneity from bovine lung by a combination of detergent extraction, ammonium sulfate precipitation, and affinity chromatography on ANP-Affi-Gel 10. The Mr of the purified receptor is about 140,000 as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. After reduction, the protein migrated as a single band with an Mr near 70,000. NH2-terminal sequence analysis of the purified material revealed only one sequence, indicating that the ANP receptor is composed of two probably identical subunits held together by disulfide bond(s), although it remains possible that one of the subunits is blocked at the NH2 terminus. Antibody was produced to the nonreduced Mr = 140,000 species and shown to interact with detergent-solubilized forms of the lung and kidney ANP receptor.  相似文献   
3.
To evaluate the specificity of cellular immune response to hepatitis B virus (HBV) Ag in patients with chronic HBV infection, we have measured IFN-gamma production and proliferation of PBMC of 16 patients with chronic active hepatitis (CAH), 17 asymptomatic carriers of HBV (ASC), 6 anti-hepatitis B surface (HBs)-positive subjects, and 6 control individuals with ELISA procedure and [3H]thymidine incorporation. There was no significant increase in the mean proliferative response to recombinant HB surface and core Ag (rHBsAg and rHBcAg), nor was IFN-gamma production elicited with rHBsAg in any group. In contrast, PBMC of HBeAg-positive and anti-HBe-positive CAH patients, and anti-hepatitis B "e" Ag (HBe)-positive ASC showed significantly enhanced IFN-gamma production in response to HBcAg, whereas those of HBeAg-positive ASC and anti-HBs-positive subjects did not respond to HBcAg. The maximal response was observed in a 5-day culture with 500 ng/ml of rHBcAg when assessed by stimulation index value. Monocytes did not demonstrate an increased suppressor or helper activity for IFN-gamma production in these patients. T cell subset fractionation revealed that CD4+ cells were main population of IFN-gamma production specific for HBcAg and CD8+ cells did not suppress IFN-gamma production of CD4+ cells. Furthermore, CD4+ cells of HBeAg-positive ASC generated lesser amounts of IFN-gamma than HBeAg-positive CAH patients did. These results show that the measurement of IFN-gamma production is useful to determine cellular immune response to HBV Ag and suggest that IFN-gamma production depends on the helper activity of CD4+ T cells sensitized to HBcAg.  相似文献   
4.
5.
L-Ascorbic acid decalcification was used for electron microscopy of mammalian tooth germs and bone after fixation in a glutaraldehyde-paraformaldehyde mixture. The recommended decalcifying solution is 2% with respect to L-ascorbic acid and 0.9% with respect to sodium chloride. The method has the advantage that decalcification is complete within a quarter of the time required with EDTA. The fine structure of ameloblasts and hard tissue is preserved as well as with EDTA.  相似文献   
6.
Summary Using the patch-clamp technique, we recorded whole-cell calcium current from isolated cardiac myocytes dissociated from the apical ventricles of 7-day and 14-day chick embryos. In 70% of 14-day cells after 24 hr in culture, two component currents could be separated from totalI Ca activated from a holding potential (V h) of –80 mV. L-type current (I L) was activated by depolarizing steps fromV h –30 or –40 mV. The difference current (I T) was obtained by subtractingI L, fromI Ca.I T could also be distinguished pharmacologically fromI L in these cells.I T was selectively blocked by 40–160 m Ni2+, whereasI L was suppressed by 1 m D600 or 2 m nifedipine. The Ni2+-resistant and D600-resistant currents had activation thresholds and peak voltages that were near those ofI T andI L defined by voltage threshold, and resembled those in adult mammalian heart. In 7-day cells,I T andI L could be distinguished by voltage threshold in 45% (S cells), while an additional 45% of 7-day cells were nonseparable (NS) by activation voltage threshold. Nonetheless, in mostNS cells,I Ca was partly blocked by Ni2+ and by D600 given separately, and the effects were additive when these agents were given together. Differences among the cells in the ability to separateI T andI L by voltage threshold resulted largely from differences in the position of the steady-state inactivation and activation curves along the voltage axis. In all cells at both ages in which the steady-state inactivation relation was determined with a double-pulse protocol, the half-inactivation potential (V 1/2) of the Ni2+-resistant currentI L averaged –18 mV. In contrast,V 1/2 of the Ni2+-sensitiveI T was –60 mV in 14-day cells, –52 mV in 7-dayS cells, and –43 mV in 7-day NS cells. The half-activation potential was near –2 mV forI L at both ages, but that ofI T was –38 mV in 14-day and –29 mV in 7-day cells. Maximal current density was highly variable from cell to cell, but showed no systematic differences between 7-day and 14-day cells. These results indicate that the main developmental change that occurs in the components ofI Ca is a negative shift with, embryonic age in the activation and inactivation relationships ofI T along the voltage axis.  相似文献   
7.
Conformations of dibucaine and tetracaine in small unilamellar phosphatidylcholine vesicles have been investigated by nuclear Overhauser effects (NOEs) in 1H nuclear magnetic resonance spectroscopy. Two-dimensional NOE and chemical exchange correlated spectroscopy (NOESY) and rotating frame NOE spectroscopy (ROESY) methods have been applied for obtaining the NOEs. In the NOESY spectra, NOEs between protons within the drug were overwhelmed by spin diffusion even at a short mixing time. This observation reduced the usefulness of the NOESY method on the one hand, however, on the other hand it facilitated remarkably in revealing signals due to the drug, hidden in the broad resonances of the membranes. In the ROESY spectra, the spin diffusion phenomena were less effective; accordingly the conformations of the drugs interacting with membranes were determined by the ROESY method. The observed NOE data showed that dibucaine takes more than two conformations and that both dibucaine and tetracaine are present as a dimer in the membranes. Molecular dynamics calculations supported these findings.  相似文献   
8.
We have devised a rapid method for examining the expression of a toxin gene following in vitro transfection using a bacterial beta-galactosidase (lacZ) gene as a reporter gene. Ricin A chain DNA and the lacZ gene, both under the control of the immunoglobulin gene promoter and enhancer, were transfected into mouse fibroblast cells (L cells). Transient expression of the lacZ gene was detected 2 days after transfection by histochemical staining of the transfectants with 5-bromo-3-indolyl-beta-D-galactoside. Cotransfection of the ricin A chain gene resulted in a progressive reduction in the number of lacZ transfectants as the expressed toxin killed the cells. A ricin construct with the intervening sequence from the human beta-actin gene required 4 days instead of 2 days to produce the toxic effect. This is a useful method for examining the expression of toxin gene in a cell.  相似文献   
9.
The heavier form of ferredoxin-NADP+ reductase was extractedfrom spinach leaves or chloroplasts and isolated as the majorfraction at high ionic strengths with ammonium sulfate or sodiumchloride. At low ionic strengths, the form with the higher molecularweight was relatively unstable and was converted gradually intothe lower form. We concluded that the enzyme exists in vivoas the form with the higher molecular weight. 1Present address: Market Development Department, Shionogi &Co. LTD., 5-Sagisu, Fukushima-ku, Osaka 553, Japan. (Received December 16, 1980; Accepted January 19, 1981)  相似文献   
10.
Summary The present study deals with cytological observations, DNA and protein synthesis in artificially activated sea urchin eggs. The eggs were activated by means of Loeb's double treatment with butyric acid and hypertonic sea water. Most of the eggs ofHemicentrotus pulcherrimus divided when the chromosomes duplicated after formation of the first monaster and other eggs divided at a later cell cycle. In the eggs ofTemnopleurus toreumaticus, however, haploid division at the first cell cycle was observed predominantly.Activated eggs that were treated for 25 min with hypertonic sea water showed a marked uptake of3H-thymidine during the two periods of 30–40 min and 90–100 min after the double treatment. These periodic changes in the3H-thymidine uptake paralleled morphological changes within the nucleus. However, these periods of increased uptake were not observed in the eggs treated with hypertonic sea water for 60 min. During exposure to hypertonic sea water, the3H-thymidine-uptake by eggs activated with butyric acid decreased gradually. When the uptake of14C-valine by eggs was measured, a very low level was seen in unfertilized eggs. The level of uptake increased strikingly when the eggs were activated with butyric acid but was suppressed by the hypertonic treatment. However, removal of the eggs to sea water allowed the uptake to return to the former high level. This pattern suggests that the hypertonic treatment has an inhibitory effect on the synthesis of protein (or enzymes) which obstruct cleavage induction.  相似文献   
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