下丘脑外侧区注射TRH对大鼠胃酸分泌的影响

本文采用连续收集胃腔灌流法,观察下丘脑外侧区(LHA)注射促甲状腺激素释放激素(TRH)对大鼠胃酸分泌的影响,并分析TRH在LHA促进胃酸分泌的作用机制。结果表明:(1)LHA注射TRH(1μg)明显地刺激胃酸分泌;(2)预先向LHA注射酚妥拉明(10μg)、美多心安(5μg)及胃泌素抗体1μl(1:640)并不影响TRH的泌酸作用,如预先向LHA注射阿托品(5μg)则可消除TRH的泌酸效应;(3)垂体摘除及肾上腺切除均不影响TRH的泌酸作用;(4)隔下迷走神经切断后,LHA注入TRH的泌酸效应仍然出现,但持续时间显著缩短;腹腔交感神经节摘除后,TRH仍能促进胃酸分泌,但分泌量少而平稳。以上结果提示:LHA是TRH中枢泌酸效应的有关结构之一,其中枢机制是通过胆碱能M受体中介的,腹腔交感神经节和膈下迷走神经是TRH泌酸效应的传出途径。前者引起的泌酸反应出现较早且引起泌酸高峰,但持续时间短;后者则引起低平的持续分泌。     

Method for rapid separation of 3,5,3'-triiodothyroacetic acid in human serum by fast protein liquid chromatography

The 3,5,3'-triiodothyroacetic acid (TRIAC) has been approved as a valuable agent in the management of hyperthyroidism secondary to inappropriate secretion of thyrotropin. We have developed a fast protein liquid chromatography (FPLC) method for separation and quantification of TRIAC. Serum samples charged with TRIAC were extracted with methanol/ammonium acetate, the supernatants were evaporated to dryness, reconstituted in NaOH and injected on a reversed phase column for chromatography. For separation an isocratic elution method (methanol water; 0.1% trifluoroacetic acid) was used. The area under the curve (ml%) was compared with those of the calibration curves. Recoveries were 70 +/- 10.8%. TRIAC was eluted in 2.33 ml. Conclusively, the present method shows that TRIAC can be measured by FPLC and may be applied to the measurement of TRIAC in pharmacological studies.     

Functional characteristics of calcitonin gene-related peptide receptors in human Ewing's sarcoma WE-68 cells

Calcitonin gene-related peptide (CGRP) receptor activity was studied in WE-68 human Ewing's sarcoma cells. 125I-human CGRP bound in a time-dependent, reversible and saturable manner. Scatchard plots were compatible with the presence of a homogenous population of CGRP receptors with high affinity (Kd = 15 pM, and Bmax = 1.9 fmol/mg protein). The potency order of unlabeled peptides in the presence of radioligand, was: human CGRP-II greater than human CGRP = chick CGRP greater than rat CGRP = rat [Tyr0]CGRP greater than human [Tyr0] CGRP much greater than salmon calcitonin (CT) greater than rat [Tyr0]CGRP-(28-37). Each peptide except CT and [Tyr0]CGRP-(28-37) stimulated cyclic AMP generation in a concentration-dependent manner, and the relative potencies paralleled their relative ability in inhibiting 125I-human CGRP binding. We conclude that WE-68 Ewing's sarcoma cells express genuine CGRP receptors which upon activation lead to stimulation of cyclic AMP formation     

RNA recombination of murine coronaviruses: recombination between fusion-positive mouse hepatitis virus A59 and fusion-negative mouse hepatitis virus 2.

It has previously been shown that the murine coronavirus mouse hepatitis virus (MHV) undergoes RNA recombination at a relatively high frequency in both tissue culture and infected animals. Thus far, all of the recombination sites had been localized at the 5' half of the RNA genome. We have now performed a cross between MHV-2, a fusion-negative murine coronavirus, and a temperature-sensitive mutant of the A59 strain of MHV, which is fusion positive at the permissive temperature. By selecting fusion-positive viruses at the nonpermissive temperature, we isolated several recombinants containing multiple crossovers in a single genome. Some of the recombinants became fusion negative during the plaque purification. The fusion ability of the recombinants parallels the presence or absence of the A59 genomic sequences encoding peplomers. Several of the recombinants have crossovers within 3' end genes which encode viral structural proteins, N and E1. These recombination sites were not specifically selected with the selection markers used. This finding, together with results of previous recombination studies, indicates that RNA recombination can occur almost anywhere from the 5' end to the 3' end along the entire genome. The data also show that the replacement of A59 genetic sequences at the 5' end of gene C, which encodes the peplomer protein, with the fusion-negative MHV-2 sequences do not affect the fusion ability of the recombinant viruses. Thus, the crucial determinant for the fusion-inducing capability appears to reside in the more carboxyl portion of the peplomer protein.     

立枯丝核菌蛋白质电泳图谱研究 Ⅰ.融合群与图谱的相关性

用来自日本和美国的立枯丝核菌8个融合群11个类群代表菌株进行可溶性蛋白质电泳,其结果表明,各融合群及亚群之间电泳图谱有显著差异,而同一类群菌株的电泳图谱则相似。分析来源于华东等地已鉴定的融合类群117个菌株的电泳图谱显示,同一融合群内菌株,虽然采集地区、寄主植物或致病力不同,其蛋白质图谱仍十分相似;而不同融合类群的菌株,即使在同一田块中同一种寄主植物上引起相似病害,其图谱也显示出明显差异。本文就上述可溶性蛋白质图谱显示的结果与其它研究者在血清学、DNA同源性.酯酶等生化水平上对融合群的研究结果进行了比较和探讨。     

Monoclonal antibody detection of transformation associated protein (TAP) in ts110 Moloney murine sarcoma virus transformed 6M2 cells that are different from the mos gene product

By the use of a highly specific monoclonal antibody (designated MC), we were able to detect three radiolabeled bands with molecular weights of 60,000, 63,000, and 66,000 daltons in the ts-110 Moloney murine sarcoma virus mutant-transformed rat kidney cells known as 6M2. Expression of transformation properties as well as these three bands in 6M2 cells was found to be temperature sensitive. Therefore, MC detected factors that are apparently associated with the transformation of 6M2 cells. These factors are tentatively referred to as transformation associated proteins. These transformation proteins were found in two other Moloney murine sarcoma virus-transformed rat cell lines. These proteins were found to differ from known gene products of the ts-110 Moloney murine sarcoma virus mutant and do not have kinase activity. The transformation associated proteins may represent rat cellular factors activated during the transformation of rat cells by Moloney murine sarcoma virus.     

中华白蛉的自育性研究

现场及实验室结果表明,我国黄土高原的大多数中华白蛉(Phlebotomus chinensis)应属自育性品系,它通常在羽化后、吸血前经交配能依靠腹节内脂肪体发育卵泡,一般在产卵后始行吸血。其生理性状是:胃内无血、腹节内有大量块状或条状脂肪体。羽化24小时后,附腺内有暗色颗粒,卵巢内有发育的卵泡。在25℃士1℃下它的生活史分快、慢两型。快型从卵至成虫仅需44—50夭,慢型需要以四龄幼虫滞育,其长短随滞育期而定,最长的滞育期达301天。观察了白蛉幼虫在饥饿状态下对自育性的影响。此外,还比较了吸血白蛉与自育性白蛉的妊卵数。吸血白蛉的妊卵数约较自育性的高出1/5。这种自育性品系的中华白蛉在自然居群约内占92%、主要栖于洞穴内为野栖种类。本文对自育性中华白蛉的生态及其防制策略作了分析和讨论。