RESPIRATION OF RAT PERITONEAL MAST CELLS

Methods for microgasometry of a few hundred mast cells are described. The Cartesian ampulla diver technique is used. The sample size is determined by counting the cells within the diver. The respiration rates at 37°C, expressed in microliters per cell per hour, are 0.29 x 10^-6 without substrate and 0.47 x 10^-6 with glucose.     

INHIBITION OF 5''-NUCLEOTIDASE IN RAT BRAIN BY METHYLXANTHINES

—Rat brain 5′-nucleotidase (EC 3.1.3.5) is inhibited by methylxanthines such as theophylline. Inhibition of the 5′-nucleotidase by theophylline appears more efficient than the inhibition of cAMP phosphodiesterase by this drug. A similar inhibition is observed with caffeine, theobromine, 7′-methyl-xanthine and 1-methylxanthine.     

RADIOIMMUNOASSAY OF METHIONINE-AND LEUCINE-ENKEPHALINS IN REGIONS OF RAT BRAIN AND COMPARISON WITH ENDORPHINS ESTIMATED BY A RADIORECEPTOR ASSAY

Abstract— Radioimmunoassays (RIAs) selective for methionine-enkephalin (Met-ENK) and leucineenkephalin (Leu-ENK) have been developed using competition towards binding of 10 pM ¹²⁵I-enkephalins to antibodies raised in rabbits against ENKs coupled to ovalbumin with carbodiimide. The high sensitivity of the RIAs (IC₅₀ 0.57 n m and 0.55 n m for Met- and Leu-ENK, respectively) allowed estimation of the enkephalin content in extracts of all rat brain regions. Regional levels are compared with those determined on the same extracts by a radioreceptor assay (RRA) using competition towards binding of 5 n m [³H]Leu-ENK to rat striatal membranes. Optimal conditions for killing the animals and extracting the endorphins have been carefully investigated: killing by rapid microwave irradiation was not found necessary as long as brain regions were homogenized into 0.1 n -HCl before deproteinization.
Marked differences both in total endorphins (RRA) and ENKs (RIA) between regions are observed with similar ranking of the various regions: highest levels are found in striatum and hypothalamus and lowest in cerebellum and hippocampus. In each region the total ENK levels (RIA) represent only 2–13% of the total endorphins (RRA) suggesting the presence of large amounts of endorphins other than the ENKs.     

DETERMINATION OF SOME MOLECULAR PARAMETERS OF TRYPTOPHAN HYDROXYLASE FROM RAT MIDBRAIN AND MURINE MAST CELL

Amphetamine, a potent sympathomimetic amine, has powerful stimulant actions in the central nervous system. These actions are believed to be related to the influence of amphetamine on release and uptake of catecholamine neurotransmitters. The [¹⁴C]deoxyglucose method makes it possible to study changes in cerebral metabolic rate in different areas of gray and white matter. Because of the close relationship between metabolic rate and functional activity, this method may be used to identify specific structures in the brain in which functional activity is altered. The [¹⁴C]deoxyglucose method was used to explore for changes in metabolic rate produced by d-and l-amphetamine (5 mg/kg) in forty gray and four white matter structures in normal conscious rats. d-Amphetamine produced increases in local cerebral glucose utilization in a number of components of the extrapyramidal motor system, as well as in some other structures known to contain dopamine-producing and/or dopaminoceptive cells. The largest increases after d-amphetamine administration occurred in the subthalamic nucleus and the zona reticulata of the substantia nigra. l-Amphetamine produced increases in some but not all of these same structures, and these were generally smaller than those observed with d-amphetamine. Decreases in local cerebral glucose utilization after either d- or l-amphetamine administration were found in the habenula and the suprachiasmatic nuclei of the hypothalamus. The effects in the suprachiasmatic nuclei may reflect their normal diurnal rhythm in metabolic rate. These results indicate that amphetamines may influence behavior through effects on specific regions of the brain. Only some of these regions have previously been studied as possible sites of action of amphetamine.     

IN VIVO INHIBITION OF RAT BRAIN PROTEIN SYNTHESIS BY d-AMPHETAMINE

Abstract— Between 1 and 4 h after rats received a single injection of d-amphetamine (15 mg/kg)(when brain polysomes are known to be disaggregated), the in vivo incorporation of [¹⁴C]lysine into trichloroacetic acid-precipitable brain protein was reduced by 28–48%. Incorporation of the ¹⁴C label into the protein present in a 100,000 g supernatant extract of whole brain was similarly reduced (by 44%). Amphetamine administration suppressed protein synthesis in rat cerebral cortex, cerebellum, hypothalamus, striatum, and brainstem to an equivalent extent. The drug did not significantly affect lysine pool sizes measured in these brain regions; thus the reduced incorporation of labeled lysine was not the result of an isotope dilution effect. We therefore conclude that the brain polysome disaggregation resulting from amphetamine administration is associated with decreased in vivo synthesis of some brain proteins.     

INHIBITION BY APOMORPHINE OF DOPAMINE DEAMINATION IN THE RAT BRAIN

Abstract— Apomorphine (A) inhibited dopamine deamination by rat brain mitochondria, but did not influence catechol- O -methyltransferase (COMT) activity by brain homogenates. The administration of apomorphine (10mg/kg i.p.) to normal rats increased brain dopamine (DA) by 34 per cent and decreased homovanillic acid (HVA) and dihydroxyphenylacetic acid (DOPAC) by 60 per cent. In rats treated with reserpine 15 min prior to A, the latter prevented the rise of cerebral HVA and DOPAC and the depletion of DA produced by the former. Finally, A decreased the L-DOPA-induced accumulation of HVA and DOPAC in the rat basal ganglia. These results indicate that A inhibits DA deamination by monoamine oxidase.
This inhibition seems to be specific since apomorphine did not influence 5-HIAA levels in normal rats and prevented neither central 5-HT depletion nor 5-HIAA rise induced by reserpine.     

IN VIVO INHIBITION OF RAT BRAIN PROTEIN SYNTHESIS BY l-DOPA

Abstract— A study has been made of the effect of a single intraperitoneal dose of l -DOPA on the in vivo metabolism of [¹⁴C]leucine and [¹⁴C]lysine by the brain, and on their uptake into brain protein. Administration of 500 mg DOPA/kg to 40-g rats raised the concentrations of several free amino acids; the only amino acid which underwent a statistically significant increment was alanine. Intracisternally-injected [U-¹⁴C]leucine was rapidly metabolized to other labelled compounds; DOPA administration did not influence significantly the rate of its metabolism. No similar metabolic change was observed after administering [U-¹⁴C]lysine intracisternally.
Incorporation of [¹⁴C]leucine and [¹⁴C]lysine into total brain protein was significantly reduced 45 min after DOPA administration. There was also depression of the uptake of labelled amino acid into a supernatant fraction, obtained by high speed centrifugation of the brain homogenate, and into brain microtubular protein (tubulin). Reduced amino-acid incorporation into brain proteins observed 45 min after l -DOPA injection coincided with extensive disaggregation of brain polyribosomes. At 120 min after DOPA treatment, disaggregation was no longer significant and there was a smaller depression in labelled amino aicd incorporation, which disappeared completely 240 min after l -DOPA injection. It is concluded that disaggregation of brain polysomes following DOPA treatment is an accurate reflection of a change in the intensity of brain protein synthesis in vivo.     

ERYTHROID CELL DIFFERENTIATION AND THE INHIBITION OF CYTOKINESIS BY CYTOCHALASIN

Cytochalasin B produces multinucleated erythroid cells in tissue cultures of very young chick blastoderms. There is no apparent qualitative interference with differentiation and maturation of erythroid cells, but the amounts produced are reduced 4- and 10-fold. These effects of cytochalasin are readily reversible.     

复方大黄配伍抗生素腹腔灌注法治疗急性出血坏死性胰腺炎的实验研究

目的：实验观察大黄复方与抗生素配伍腹腔灌注对急性出血坏死性胰腺炎(ANP)的作用。方法：制备ANP模型,随机分组后分别以腹腔灌注给药,以ELISA法及鲎试验法检测血浆或组织中自细胞介素—6(IL—6)和内毒素脂多糖(LPS)水平。结果：各治疗组IL—6、LPS水平均明显低于实验对照组(非治疗组)。结论：大黄复方配伍头孢哌酮钠腹腔灌注法对ANP大鼠内毒素和炎性介质的产生有一定的抑制作用。     

非甾体抗炎药抑制大鼠血管平滑肌细胞增殖

本文研究了aspirin、ibuprofen和sulindac三种不同结构的非甾体抗炎药(NSAID)对大鼠A10血管平滑肌细胞(VSMC)增殖的影响并探讨其作用机制。方法:细胞计数法观察不同浓度的三种NSAID对细胞增殖的影响,乳酸脱氢酶(LDH)释放分析法测定NSAID的细胞毒作用,流式细胞术分析测定细胞周期。结果:aspirin、ibuprofen和sulindac三种NSAID都对A10 VSMC的增殖有明显抑制作用,且其作用是浓度依赖性的,IC_(50)分别是:aspirin为1666μmol/L,ibuprofen为937μmol/L,sulindac为520μmol/L;其抑制作用不是因细胞毒作用引起;三种NSAID对细胞周期的作用不同,ibuprofen(1000μmol/L)和sulindac(750μmol/L)将细胞阻抑在细胞周期的G_1期(从68.7±2.0%上升到76.6±2.2%和75.8±2.2%,P<0.05),而aspirin(2500μmol/L)对处于细胞周期各期的细胞百分率无明显改变;利用有丝分裂抑制剂nocodazole辅助分析,更清楚地检测到了ibuprofen和sulindac在G_1阻抑,而aspirin仍然不引起处于细胞周期各期的细胞百分率的明显改变。结论:aspirin抗A10 VSMC的增殖作用机制与ibuprofen和sulindac两者的作用机制不同,本研究为三种NSAID成为VSMC增殖性疾病的治疗药物提供了理论依据。     

INHIBITION OF MALIGNANT CELL PROLIFERATION BY CULTURE MEDIA CONDITIONED BY CARDIAC OR SKELETAL MUSCLE

The present work is an attempt to explain the high resistance of muscles to cancer development. We used primary cultures of rat skeletal and cardiac muscle, and examined the effect of the supernatant of these cultures (conditioned medium; CM) on proliferation of cancer cells. The results demonstrated that CM inhibited the proliferation of several types of malignant cells by more than 50%, without a significant inhibition on normal cells. Cell cycle analysis revealed that CM increased the number of cells in S and G2 phases, suggesting a cytostatic effect of CM. For defining the biological properties of the factor(s) which are present in the CM, skeletal muscle cultures were grown in chemically defined medium (serum free medium). The concentrated sample was applied to a Sephadex G-50 column and three fractions were obtained. Only one fraction showed inhibitory activity. Four protein bands were observed in this fraction, as revealed by SDS-PAGE. We suggest that some, or all of these proteins are responsible for inhibition of tumor cell replication.     

经血管灌流生长抑素对大鼠离体胃运动的抑制作用

采用血管灌流大鼠离体胃模型,探讨生长抑素对胃运动的影响。结果表明：（１）生长抑素能明显抑制胃窦自发和胃动素兴奋的胃运动;（２）生长抑素可抑制离体胃内源性胃泌素释放;（３）抗生长抑素血清和前列腺素合成酶抑制剂消炎痛可阻断生长抑素对胃窦运动的抑制作用。上述结果提示：生长抑素的抑制作用除通过直接作用于生长抑素受体外,还可能通过胃窦局部前列腺素介导来抑制胃的运动。     

异丙酚抑制大鼠心室肌细胞短暂外向钾电流

利用全细胞膜片箝技术研究了异丙酚２５,５０μｍｏｌ／Ｌ对离体大鼠心室肌细胞短暂外向钾通道电流的影响。观察到用药后Ｉｔｏ的幅度明显减小,而用不含药物的灌流液冲洗细胞,可使受抑电流部分恢复。     

核酶抑制ECV304细胞TXS mRNA的表达

目的 从设计针对人TXSmRNA的核酶中,筛选能显著抑制TXSmRNA表达的核酶。方法 将核酶DNA亚克隆到真核pEGFP,经脂质体转染入ECV304细胞后,用RT-PCR方法测定细胞内TXSmRNA的相对含量。结果 核酶R416,R441能显著抑制ECV304细胞TXSmRNA的表达。结论 核酶可望成为人TXS有效的抑制剂。在有关TXS的基因治疗中发挥作用。     

STUDIES ON CELL METABOLISM AND CELL DIVISION : II. STIMULATION OF CELLULAR OXIDATION AND REVERSIBLE INHIBITION OF CELL DIVISION BY DIHALO AND TRIHALOPHENOLS

The dihalo and trihalophenols, and phenols containing both halo and nitro substituents in the same molecule, produce, in fertilized eggs of Arbacia punctulata, a rise in rate of oxygen consumption and a reversible block to cell division. To define the conditions which affect the degree of this activity, the following factors have been varied: the arrangement of substituents in the molecule, the concentration of reagent, and the time after fertilization at which the reagent is added. The stimulation of oxygen consumption and reversible block to cell division produced by the dihalophenols are qualitatively the same as those previously produced in fertilized Arbacia eggs by certain dinitrophenols. To yield optimum respiratory effect and maximum division block, it usually requires a higher concentration of dihalo than of the corresponding dinitrophenol. For example, with fertilized Arbacia eggs at 20°C. 2,4-dinitrophenol, in optimum concentration of 3 x 10^–5 molar, raises oxygen consumption to 292 per cent of normal (4). The corresponding values for two dihalo analogues are: 2,4-dichlorophenol, 10^–4 molar and 236 per cent; 2,4-dibromophenol, 6 x 10^–5 molar and 282 per cent. The halophenols differ from the nitrophenols in two interesting respects: (a) The monohalophenols produce little or no oxidative stimulation or division block in fertilized Arbacia eggs; p-nitrophenol is very active in both respects. (b) The symmetrical trihalophenols have an appreciable ability to stimulate oxygen consumption and block division; symmetrical trinitrophenol is inactive in both respects (4). The increases in oxygen consumption produced in fertilized Arbacia eggs by 2,4-dichloro and 2,4-dinitrophenol are larger than the percentage increases given by methylene blue and o-cresol indophenol under the same experimental conditions. The dihalo and dinitrophenols produce a reversible block to the cell division of fertilized marine eggs. The oxidation-reduction indicators, in contrast to the dihalo and dinitrophenols, block cell division irreversibly and fertilized eggs of Arbacia do not recover from optimum respiratory stimulating concentrations of these oxidation-reduction dyes. The present experiments with halophenols are in harmony with and lend considerable support to the hypothesis (4) that nitro and similarly substituted phenols derive their biological activity from the presence and properties of the phenolic OH group, as modified by proper substitution in the phenolic benzene ring.     

INHIBITION OF THE BIOSYNTHESIS OF ISOPRENOID COMPOUNDS BY PHENOLIC ACIDS IN THE RAT BRAIN

—The incorporation of [2-¹⁴C]mevalonate into nonsaponifiable lipids by rat brain homogenates is inhibited by phenolic acids derived from tyrosine. The phenyl acids derived from phenylalanine are inhibitory only at very high concentrations compared with phenolic acids. The brain is more sensitive to inhibition by the phenolic acids than the liver. These studies indicate a possible role for phenolic acids in the impairment of cerebral sterol metabolism in phenylketonuria.     

维生素C衍生物对癌细胞浸润转移能力的抑制作用机理研究

前期研究表明Asc2P6P1m能够有效地抑制癌细胞的浸润转移。本文试图以Asc2P6P1m对人成纤维瘤细胞浸润转移作用探讨维生素C衍生物对癌细胞转移能力抑制的机理。对HT-1080细胞分别以50—300μmol/LAsc2P6P1m处理1h,随着Asc2P6P1m浓度的增大,细胞移动的数目明显减少,Asc2P6P1m对HT-1080细胞移动的抑制作用呈现出量效关系。Asc2P6P1m对ROS的清除作用,通过自旋捕集剂DMPO以电子自旋共振方法进行研究。HT-1080细胞经Asc2P6P1m处理后,细胞内的自由基水平与对照组相比有显著的降低。用F-actin的分子探针NBD研究表明,随处理时间延长,细胞内荧光强度与对照组相比显著降低。Western blots研究表明,细胞核内的RhoA蛋白量随Asc2P6P1m处理时间延长而逐渐增加。研究提示,Asc2P6P1m对癌细胞浸润转移能力的抑制作用是与抑制癌细胞内的ROS、提高细胞核内RhoA水平、降低细胞质内F-actin相关。     

MATURATION OF RAT MAST CELLS : An Electron Microscope Study

Electron microscope study of rat mast cell maturation corroborates certain interpretations of features of mast cell differentiation based on light microscope studies. In addition, the ultrastructural variation observed in the granules of differentiating mast cells suggests that granule formation begins with the elaboration of dense granules about 70 mµ in diameter inside Golgi vacuoles. These progranules appear to aggregate inside a membrane and fuse to form dense cords 70 to 100 mµ in diameter. These dense cords are embedded in a finely granular material possibly added to the developing granule by direct continuity between perigranular membranes and cisternae of rough endoplasmic reticulum. The dense cords and finely granular material then appear to be replaced by a mass of strands about 30 mµ in diameter, thought to be a reorganization product of the two formerly separate components. A process interpreted as compaction of the strands completes the formation of the dense, homogeneous granules observed in mature rat mast cells. The similarity between mast cell granule formation and the elaboration of other granules is considered, with special reference to rabbit polymorphonuclear leukocyte azurophil granules. The relationships between the ultrastructural, histochemical, and radioautographic characteristics of mast cell granule formation are considered, and the significance of the perigranular membrane is discussed.