鲨鱼软骨制剂抑制血管生成的研究

以鲨鱼软骨为原料,经盐酸胍抽提,丙酮分级沉淀, 超滤等步骤得到鲨鱼软骨制剂(shark cartilage preparation,SCP). 利用整装细胞扫描电镜方法测定SCP对血管内皮细胞骨架系统的影响,体外细胞迁移实验测定它对内皮细胞迁移的抑制效应,及鸡胚绒毛尿囊膜实验测定对血管生成的抑制效应. 结果表明SCP能显著抑制内皮细胞的骨架形成;显著抑制内皮细胞的迁移,并有明显的浓度依赖关系;显著抑制鸡胚绒毛尿囊膜的血管生成. 细胞骨架是细胞分裂增殖及运动迁移的基础,血管内皮细胞的运动迁移又是血管生成的基础,因此SCP的作用机理可能是通过抑制细胞骨架的形成,抑制内皮细胞的运动迁移,从而抑制血管生成.     

Isolation and culture of daylily mesophyll protoplasts

Mesophyll protoplasts were isolated from leaf tissues of a diploid daylily (HemerocallisxRed Magic) by enzymatic digestion with a solution containing 0.5% Pectolyase Y-23, 0.1% Cellulase R-10, 0.1% Driselase, 0.6 M sorbitol and half-strength MS inorganic salts. When cultured on MS medium supplemented with 0.5 mg/l NAA and 0.5 mg/l BA, the protoplasts underwent sustained division to produce multicellular colonies. The optimal plating density for cell division was 0.5 × 10⁵ protoplasts/ml. The highest plating efficiency was obtained in cultures grown in media solidified with 0.2% Gelrite. Under these conditions, formation of colonies occurred from 14% of cultured protoplasts. Calli were recovered from 9 colonies only after the cultures were treated with a conditioned medium. Intact plants were regenerated from protoplast-derived calli through organogenesis.Abbreviations BA 6-benzylaminopurine - FDA fluorescein diacetate - GA₃ gibberellic acid - MS medium Murashige and Skoog (1962) medium - NAA 1-naphthaleneacetic acid     

外显子和内含子的序列复杂性

引入了两个新的关于序列复杂性的测度,并以此为指标分析比较了结构基因序列中的外显子和内含子的复杂性差异。     

The distribution of alpha-melanocyte stimulating hormone (alpha-MSH) in the central nervous system of the rat: an immunohistochemical study. II. Lower brain stem

The distribution of immunoreactive alpha-melanocyte stimulating hormone (alpha-MSHI) in the rat lower brain stem was examined by indirect immunofluorescence or peroxidase- anti-peroxidase immunohistochemical method using an antiserum against synthetic alpha-MSH. The results confirmed the presence of alpha-MSHI fibers in the midbrain central gray matter and parabrachial area, and demonstrated a much more extensive distribution of these fibers in various parts of the lower brain stem areas previously thought not contain alpha-MSHI fibers. In addition, the commissural nucleus was identified as a new alpha-MSHI neurons-containing site. No alpha-MSHI neurons were seen in other regions of the rat lower brain stem.     

Plasma growth hormone responses to repetitive administrations of growth hormone releasing factor in patients with pituitary dwarfism

Plasma growth hormone (GH) responses to the repetitive administrations of synthetic human pancreatic growth hormone releasing factor (hpGRF-44) were studied in 15 patients with GH deficiency (11 diagnosed as idiopathic and 4 diagnosed as secondary to hypothalamo-pituitary tumor). hpGRF-44 was administered by single iv bolus (2 micrograms/kg), repetitive im (100 micrograms, twice a day), and/or repetitive iv infusion (2.5 micrograms/min for 90 min, once a day) for three to six consecutive days. Three of the eleven idiopathic GH deficient patients had plasma GH responses to both single iv bolus injection and repetitive administrations by im, or iv infusion of hpGRF. In four of the remaining eight, who had not had peak plasma GH levels above 5 ng/ml to a single iv bolus of the peptide, repetitive administrations of hpGRF-44 by im injection and/or iv infusion induced GH responses to the peptide. In the four patients with secondary GH deficiency, three had plasma GH response to hpGRF administration but one patient, who had indications of pituitary disorder, did not show any plasma GH response to either single iv injection or repetitive administrations of hpGRF-44. These data show that repetitive administrations of hpGRF-44 can induce plasma GH responses in some GH deficient patients who do not respond to a single iv bolus of the peptide.     

Effects of forskolin and cholera toxin on cyclic AMP release in a neurotensin-secreting rat C-cell line

The effects of forskolin and cholera toxin on the regulation of cAMP release were studied in a neurotensin-secreting rat C-cell line. The interaction of these agents with norepinephrine, a potent neurotensin secretagogue, was also investigated. Forskolin stimulated cAMP release 10(2)-10(3) fold while it increased neurotensin release 2-3 fold. Cholera toxin caused a 10(2)-10(3) fold increase in cAMP release and had no effect on neurotensin release. We conclude that the 44-2 C-cells provide a new model for studying the regulation of the concomitant (via forskolin) or independent (via cholera toxin) secretion of cyclic AMP and/or neurotensin.     

Topographical and ontogenetic study of the neurons producing growth hormone-releasing factor in human hypothalamus

Neurons producing growth hormone-releasing factor have been characterized and analyzed by immunohistochemistry in the hypothalami of human fetuses, neonates, infants and adults, using two antibodies against human pancreatic GRF (hpGRF). One of the antibodies recognized both the hpGRF(1-40)OH and hpGRF(1-44)NH2 in the mid portion (between the 28th and 39th amino acid), the other one specifically recognized the C-terminal end of hpGRF(1-44)NH2. These two antibodies stain a single neuronal system with cell bodies mainly located in the infundibular (arcuate) nucleus, and in the ventromedial and lateralis tuber nuclei. These neurons project to the median eminence where they give numerous endings in contact with portal vessels. These neurons are distinct from those containing LH-RH, somatostatin, CRF or pro-opiocortin. In fetuses, neurons immunoreactive with hpGRF antibodies are first detected at the 29th week. They display a neuroblastic aspect which persists after birth. Immunoreactive fibers are detectable in the median eminence after the 31st week. These results demonstrate that the infundibular nucleus plays a major role in control of GH secretion in man and that secretion of GRF appears late during fetal life; this suggests that the first stages of differentiation and development of GH producing cells in the human fetus do not depend on hypothalamic GRF secretion.     

Ontogeny of the response to growth hormone-releasing factor

Primary cell cultures were prepared from fetal, neonatal and adult rat pituitaries and evaluated for their ability to secrete growth hormone (GH) in response to growth hormone-releasing factor (GRF). Pituitary cells prepared from fetuses at days 19 and 21 of gestation, neonatal animals at the day of birth (day 0) or the following day (day 1) and peripubertal male rats showed full dose response curves to GRF with maximal GH release when stimulated with 1 X 10(-10) M rat GRF. At this concentration of GRF, the amount of GH released was not different from that elicited by activation of adenylate cyclase with 1 X 10(-5) M forskolin. In contradistinction, a preparation of cells from fetuses at day 18 of gestation did not show the same release of GH when challenged with 1 X 10(-10) M GRF and forskolin (0.057 +/- 0.001, compared to 0.076 +/- 0.003 micrograms/10(5) cells per 4.5 h), although the cells clearly responded to both secretagogues (basal levels of GH, 0.029 +/- 0.002 micrograms/10(5) cells per 4.5 h). While cells prepared from fetuses at day 21 of gestation or from animals after birth released 5-10% of their total cellular GH content, those prepared from 18- and 19-day fetuses released as much as 40% of their total GH suggesting there is a maturation of intracellular GH processing that occurs late in gestation. The results show that, in late pregnancy, the rat fetal pituitary is highly responsive to growth hormone-releasing factor and suggest that this peptide participates in regulating GH levels during the perinatal period.     

东莨菪碱镇痛作用的研究

腹腔(25或50mg/kg)或侧脑室注射东莨菪碱(1mg/kg),均使大鼠的痛阈升高42—80%,并持续32—36小时之久。当在恒温室内作昼夜连续观察时,对照组的大鼠在深夜20时至次日8时之前,痛刺激反应稍有增强,此时东莨菪碱组的镇痛作用也相应地减弱,而白天的镇痛作用较强,似有昼夜规律的表现。东莨菪碱的镇痛作用与脑内阿片能系统无关,DA 能暂时增强其镇痛作用,毒扁豆碱能拮抗其镇痛作用,所以,东莨菪碱的镇痛作用,主要是阻滞中枢 M-胆碱能系统的作用所致。