Diazepam-binding inhibitor: a neuropeptide located in selected neuronal populations of rat brain

An endogenous polypeptide of rat brain has been identified that is capable of displacing 1,4-benzodiazepines and the esters of the 3-carboxylic acid derivatives of beta-carbolines from their specific synaptic binding sites. This polypeptide was termed diazepam-binding inhibitor (DBI). Previous studies have shown that DBI injected intraventricularly in rodents elicits "proconflict" responses and antagonizes the "anticonflict" action of benzodiazepines. An antiserum to this peptide, directed toward an immunodeterminant near its amino terminus, makes it possible to detect, measure, and study the neuronal location of this peptide in rat brain. In the rat cerebral cortex, DBI immunoreactivity is located in neurons that are not GABAergic (GABA, gamma-aminobutyric acid); in the cerebellum and hippocampus, however, it might be present also in GABAergic neurons.     

大鼠发情周期的子宫组织雌激素受体定位的初步研究

本试验选用 SD 系大鼠,用常规阴道抹片法鉴定发情。采用免疫组织化学的过氧化物酶—抗过氧化物酶复合物(PAP)法,进行雌激素受体(ER)定位。在子宫的内膜固有层、肌层和浆膜层,发现抗雌二醇抗体的免疫反应阳性细胞,而在内膜上皮细胞内无阳性染色。这种阳性染色可以被乙烯酚所阻断,不加抗雌二醇抗体的结果使染色呈阴性。发情周期4个不同时期的子宫组织中免疫反应阳性细胞表现出量的变化,以发情间期为基础,发情前期较多,发情期和发情后期依次减少,其动态变化与前人报道发情周期中雌二醇在血浆中的浓度变化是对应的。并发现发情周期中子宫组织的肥大细胞与雌激素受体的分布和变化有着相似的特点。     

The cholinergic neuronal differentiation factor from heart cells is identical to leukemia inhibitory factor

A protein secreted by cultured rat heart cells can direct the choice of neurotransmitter phenotype made by cultured rat sympathetic neurons. Structural analysis and biological assays demonstrated that this protein is identical to a protein that regulates the growth and differentiation of embryonic stem cells and myeloid cells, and that stimulates bone remodeling and acute-phase protein synthesis in hepatocytes. This protein has been termed D factor, DIA, DIF, DRF, HSFIII, and LIF. Thus, this cytokine, like IL-6 and TGF beta, regulates growth and differentiation in the embryo and in the adult in many tissues, now including the nervous system.     

Alpha-hydroxy acid oxidase: localization in renal microbodies

Differential and density equilibrium centrifugation have established the presence of alpha-hydroxy acid oxidase in microbodies of the kidney of the rat. The enzyme has been demonstrated in cells of the distal convoluted tubule by a microscopic cytochemical method. This enzyme, like certain others in microbodies, produces hydrogen peroxide.     

重组人乳铁蛋白对原代肝、肾细胞的毒性研究

[目的]通过模拟肝、肾毒性的体外细胞试验,研究重组人乳铁蛋白是否对小鼠原代肝肾细胞具有毒性作用,为其进一步的安全性评价提供依据。[方法]采用模拟体外消化试验所得的重组人乳铁蛋白消化产物及重组人乳铁蛋白为受试物,牛乳铁蛋白为对照,以小鼠原代肝、肾细胞为平台,用MTT法检测受试物对细胞活性的半数抑制浓度（IC50）,研究细胞毒性剂量-反应关系。[结果]在设定的试验条件下,未发现重组人乳铁蛋白对肝肾细胞存在靶毒性,结果能与已进行的亚慢性毒性试验相互印证。[结论]为对重组人乳铁蛋白的进一步安全性评价及其他转基因食品的安全性评价方法提供了参考。     

Rat transforming growth factor type 1: structure and relation to epidermal growth factor

The complete amino acid sequence of rat transforming growth factor type 1 has been determined. This growth factor, obtained from retrovirus-transformed fibroblasts, is structurally and functionally related to mouse epidermal growth factor and human urogastrone. Production of this polypeptide by various neoplastic cells might contribute to the continued expression of the transformed phenotype.     

重组人乳铁蛋白对原代肝·肾细胞的毒性研究

[目的]通过模拟肝、肾毒性的体外细胞试验,研究重组人乳铁蛋白是否对小鼠原代肝肾细胞具有毒性作用,为其进一步的安全性评价提供依据。[方法]采用模拟体外消化试验所得的重组人乳铁蛋白消化产物及重组人乳铁蛋白为受试物,牛乳铁蛋白为对照,以小鼠原代肝、肾细胞为平台,用MTT法检测受试物对细胞活性的半数抑制浓度（IC50）,研究细胞毒性剂量一反应关系。[结果]在设定的试验条件下,未发现重组人乳铁蛋白对肝、肾细胞存在靶毒性,结果能与已进行的亚慢性毒性试验相互印证。[结论]为重组人乳铁蛋白的进一步安全性评价及其他转基因食品的安全性评价方法提供了参考。     

Cloning of complementary DNA for GAP-43, a neuronal growth-related protein

GAP-43 is one of a small subset of cellular proteins selectively transported by a neuron to its terminals. Its enrichment in growth cones and its increased levels in developing or regenerating neurons suggest that it has an important role in neurite growth. A complementary DNA (cDNA) that encodes rat GAP-43 has been isolated to study its structural characteristics and regulation. The predicted molecular size is 24 kilodaltons, although its migration in SDS-polyacrylamide gels is anomalously retarded. Expression of GAP-43 is limited to the nervous system, where its levels are highest during periods of neurite outgrowth. Nerve growth factor or adenosine 3',5'-monophosphate induction of neurites from PC12 cells is accompanied by increased GAP-43 expression. GAP-43 RNA is easily detectable, although at diminished levels, in the adult rat nervous system. This regulation of GAP-43 is concordant with a role in growth-related processes of the neuron, processes that may continue in the mature animal.     

Demonstration of biological activity of a murine leukemia virus of New Zealand black mice

Although New Zealand Black mouse embryo and adult tissues show evidence of murine leukemia viral particles and antigens, efforts to demonstrate biological activity of a murine leukemia virus by standard methods have proved negative. Cocultivation of tissues of these mice with non-virus-yielding hamster cells transformed by Moloney sarcoma virus, however, has resulted in the rescue of a pseudotype sarcoma virus, presumably carrying the New Zealand Black mouse leukemia virus coat. This virus has an unusual host restriction, producing foci of cell alteration only in rat cells.     

1alpha-Hydroxyvitamin D2: a potent synthetic analog of vitamin D2

A hydroxy analog of vitamin D(2), 1alpha-hydroxyvitamin D(2), has been synthesized and tested for biological activity. This vitamin derivative is active in stimulating intestinal calcium transport and bone calcium mobilization in the rat and exhibits antirachitic activity. Its biopotency is comparable to that of the corresponding vitamin D(3) analog, 1alpha-hydroxyvitamin D(3).     

Ribosomes: a common structural feature

A reflection between 45 and 50 A has been observed in x-ray diffraction patterns from ribosomes extracted from Escherichia coli, Drosophila larvae, rat liver, and rabbit reticulocytes. This spacing appears to correspond to a common substructural feature within the ribosomes. The intensity distribution is consistent with a model in which part of the RNA is in the form of four or five parallel double helices 45 to 50 A apart.     

Perfusion preservation of hearts for 6 to 9 days at room temperature

The combination of a defined medium with single-pass perfusion has made possible long-term maintenance of beating rat hearts at 22 degrees C in vitro. The 6- to 9-day survival period appears to be the longest so far reported for hearts. This method provides a stable system which should be useful for investigating the role of single factors in myocardial preservation and evaluating the effects of exposure to pharmacological and toxicological agents.     

Acetylcholine concentrations in rat brain: diurnal oscillation

A diurnal oscillation of acetylcholine concentrations in rat brain has been demonstrated by gas chromatography. Peak concentrations occur at 2 hours of light, and a trough is seen at 6 hours of darkness. This pattern is observed only in grouped rats, and emerges after at least 18 days of prior conditioning in an environment with controlled light, humidity, and temperature.     

Spontaneous impulse activity of rat retinal ganglion cells in prenatal life

The existence of spontaneous neural activity in mammalian retinal ganglion cells during prenatal life has long been suspected. This activity could play a key role in the refinement of retinal projections during development. Recordings in vivo from the retinas of rat fetuses between embryonic day 17 and 21 found action potentials in spontaneously active ganglion cells at all the ages studied.     

Dihydroxyphenylalanine in rat food containing wheat and oats

Dopa has been identified in rat food by three different fluorimetric assays and paper chromatography. Incubation of the rat food with proteolytic enzymes dramatically increased the measurable free dopa. Analysis of samples of six individual protein-containing constituents of rat food revealed that both wheat and oats contain dopa.     

Tryptophan hydroxylation: measurement in pineal gland, brainstem, and carcinoid tumor

Development of a rapid and sensitive radioassay has permitted study of the conversion of tryptophan to 5-hydroxytryptophan in mammalian tissues. Of normal tissues examined, beef and rat pineal gland contained the highest activity. This is the first direct demonstration of tryptophan hydroxylase in this hydroxyindole-rich tissue. Rat and rabbit brainstem and human carcinoid tumor also had quantities of enzyme that could be measured easily. The reaction requires a reduced pteridine and oxygen and is inhibired by Para-Chorophenylalanine.     

中药制剂“HD”对小鼠微核及精子畸形的影响

本试验用昆明种小白鼠对中药制剂“HD”进行微核试验和精子畸形试验。结果表明：小白鼠微核试验和精子畸形试验均呈阴性反应,中药制剂“HD”无致突变作用。     

Antireceptor antiserum causes specific inhibition of reactivity to rat histocompatibility antigens

The antigen receptor of lymphocytes destined to form antibody appears to have the characteristics of the immunoglobulin produced. Antibody directed against the combining region of this immunoglobulin should interact with the combining region of the cell receptor for the antigen. Purified Lewis rat alloantibody prepared against Brown Norway (BN) rat histocompatibility antigens was used to immunize L x BN F(1) hybrids. The resultant antiserum has anti-receptor activity because (i) it yields precipitin lines in gel diffusion when reacted against the immunizing alloantibody; (ii) it inhibits the hemagglutinin antibody response of Lewis rats to BN histocompatibility antigens; and (iii) it inhibits the local graft-versus-host response of Lewis lymphoid cells against BN antigens. This suggests that antireceptor antibody may inhibit cell-mediated responses as well as antibody responses to histocompatibility antigens and may play a role in the regulation of immune responses to such antigens.     

Genomics. Rat genome off to an early start

The National Human Genome Research Institute has jump-started efforts to determine the order of the roughly 3 billion bases in the rat genome. The original plan had been to wait for funding, expected in fiscal year 2001. Instead, two of the 10 centers involved in sequencing the mouse genome are shifting to the rat now.