人牙根龋发生中有机质破坏的酶学研究

目的 :了解牙根部有机质破坏的机制。方法 :将健康恒牙根颈 1/ 3牙体硬组织 ,磨制成 38.5～149m组织粉粒作样本 ,乳酸 (p H 4.0和 p H5 .5 )及醋酸 (p H 4.5和 p H5 .5 )溶液预处理后 ,测定钙、总蛋白和胶原含量 ;再经胰酶、胶原酶处理后分析释出的胶原量。结果 :乳酸和醋酸预处理不能降解人牙根部的胶原 ,但采用 p H4.0的乳酸处理牙齿后可以使酶对牙本质胶原的降解量明显增高 ,达 (4 4.0 5± 4.5 0 ) μl/ mg;随 p H升高 ,胰酶和胶原酶对根部牙体组织胶原的降解量明显下降 ,脱矿程度减弱 ,钙释出减少。结论 :酸和酶有协同降解胶原的作用。     

桑蚕金属硫蛋白基因在大肠杆菌中的克隆和表达

用\%Bam\%HⅠ和\%Sac\%Ⅰ双酶切质粒pCM1\|1,获得酵母的MTI基因片段,用非放射性地高辛标记作为探针。提取桑蚕肥苏蚕卵的总DNA,分别用\%Eco\%RⅠ、\%Bam\%HⅠ和\%Hin\%dⅢ酶切,与MTI探针进行Southern杂交,出现较强的杂交信号。然后用\%Eco\%RⅠ完全酶切桑吞的总DNA,电洗脱法回收1～6kb的染色体片断,与\%Eco\%RⅠ酶切的M13-载体以3∶1比例连接,转化受体菌DH5α。筛选到4 000多个白色转化子,与探针MTI进行Southern杂交筛选阳性转化子,选择到有强杂交信号的三个转化子［编号为T1(pZHC\|1)\,T5(pZHC\|5)\,T7(pZHC\|7)\]。用12种限制性内切酶对pZHC\|5重组质粒进行酶切分析表明插入片段约12kb,在基因内有一个\%Hin\%dⅢ位点。抗性测定表明受体菌DH5α在含有50mmol/L CuSO\-4的培养基上生长,在含有52mmol/L CuSO\-4的培养基上不生长,而转化子确能在含有52mmol/L CuSO\-4以上的培养基上生长。上述研究结果表明12kb左右的插入片段含有桑吞的金属硫蛋白基因。     

刺激中缝背核对视交叉上核光敏神经元单位放电的影响

本实验观察刺激中缝背核对大鼠视交叉上核光敏神经元单位放电的影响,并进行药理学分析。结果表明,刺激ＤＲ能明显抑制ＳＣＮ神经元光诱发放电,这种抑制作用能被单胺氧化酶抑制剂优降宁增强,能被５－ＨＴ合成抑制剂对氯苯丙氨酸减弱,还能被５－ＨＴ受体拮抗剂赛庚啶阻断。结果提示,５－ＨＴ参与了刺激ＤＲ对ＳＣＮ光敏神经元放电的抑制。     

不同发育时期的鸡胚色素上皮对体外视网膜细胞生长的作用(简报)

眼正常发育中,色素上皮层和视刚膜之间在结构上存在着紧密的接触,功能上也相互依赖,但色素上皮的作用不甚清楚。很多脊椎动物的视网膜如果失去了与色素上皮层的紧密     

THE USE OF TETRA- AND PENTA-CHLORONITRO-BENZENES IN THE CONTROL OF BOTRYTIS DISEASE AND RHIZOCTONIA ATTACK OF LETTUCE

Botrytis disease in the 'spring' lettuce crop was controlled by six talc dusts containing s, 10 or 20 % of tetra- or penta-chloronitrobenzene. All the dusts increased equally the final stand in the frames, but the number of seedlings with stem lesions decreased with increasing concentrations of both compounds. At similar concentrations the tetra- was more effective than the penta-compound. The percentage survival in the field was increased by the dust treatments. The 20% dust of the penta- was only as effective as the 5% dust of the tetra-compound.
The dusts affected the leaves, stunted the seedlings and delayed hearting. At similar concentrations the tetra- was more harmful than the penta-compound. The 5 % dust of the tetra- was less damaging than the 20% dust of the penta-compound.
The spread of Rhizoctonia solani was reduced by incorporating the dusts with soil. Again, the 5% tetra- dust was as effective as the penta- dust at 20%. At 12·5 g. of dust per 20 kg. of soil, none of the dusts retarded the rate of emergence of lettuce seedlings but the highest concentration of the tetra- series reduced the number emerging.
Foliage applications of two dusts, 5% tetra- and 20% penta- dusts, controlled the spread of R. solani.     

P物质对5—HT引起的大鼠回肠纵行肌收缩效应的影响及其机制分析

本文采用离体大鼠回肠纵行肌-肌间神经丛(LM-MP)标本,观察SP对5-HT引起的LMMP标本收缩效应的影响,并对其作用机制进行了分析。实验结果:(1) 阈下剂量的SP(5nmol/L)可明显加强5-HT(100nmol/L)引起的LM-MP收缩效应;(2) SP受体拮抗剂[D-Pro~2、DTrp~(7,9)]SP、M受体阻断剂阿托品可抑制或阻断SP对5-HT的加强效应。表明这种效应是通过SP受体中介的;(3) M受体阻断剂阿托品也可阻断SP的加强效应,而平滑肌5-HT受体阻断剂BOL对SP的加强效应似无阻断作用。这些结果提示,阈下剂量的SP对5-HT具有调制作用,并与胆碱能机制有关。     

THE BINDING OF 5-HYDROXYTRYPTAMINE TO BUTANOL EXTRACTS OF RAT BRAIN STEM

Abstract— When butanol-water extracts of rat brain stem were incubated with [³H]5-HT, (5 × 10⁻⁷ m ), and the components resolved by chromatography on LH₂₀ Sephadex, a peak representing approximately 70% of the eluted radioactivity was found in chloroform-methanol 4:1. The peak was not found in identically prepared extracts from rat diaphragm, neither was a similar peak found when brain extracts were incubated with [¹⁴C]ACh (10⁻⁶ m ), suggesting a degree of selectivity. Binding was not saturated at concentrations of 5 × 10⁻⁵ m -5-HT. The binding was highly sensitive to the presence of water, requiring about 15% (v/v) for optimum binding. The implications of these findings are discussed in terms of a possible '5-HT receptor'.     

DECARBOXYLATION OF EXOGENOUS l-5-HYDROXYTRYPTOPHAN AFTER DESTRUCTION OF THE CEREBRAL RAPHE SYSTEM

Abstract— l -5-Hydroxytryptophan ( l -5-HTP) was administered intravenously to rats (12 mg/kg) after inhibition of the peripheral aromatic l -amino acid decarboxylase with l -α-hydrazino-α-methyl dopa (MK 486). The accumulation of 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid in the cerebral cortex was measured 1, 2 and 4 h after injection of 5-HTP with automated assay techniques. Besides controls two groups of rats were studied: rats after inhibition of tryptophan-5-hydroxylase with p -chlorophenylalanine (pcpa) and subjects with a chronic lesion in the area of the raphe nucleus. The net accumulation of both measured 5-hydroxyindoles was diminished in rat cerebral cortex after degeneration of 5-HT containing nerve endings, compared with control animals and pcpa-treated rats. These results indicate that the formation of 5-HT in the cerebral cortex from exogenous l -5-HTP, after inhibition of the peripheral aromatic amino acid decarboxylase, occurs predominantly in 5-HT containing nerve endings possibly by a specific 5-HTP-decarboxylating enzyme.     

中国穿山甲消化道5-羟色胺免疫活性细胞的定位

目的研究中国穿山甲消化道5-羟色胺（5-HT）免疫活性细胞的分布和形态。方法应用链霉菌抗生物素蛋白一过氧化物酶免疫组织化学方法（S-P法）。结果中国穿山甲消化道5-HT细胞在胃幽门部密度最高,食道、胃贲门部和胃体中未见分布。肠道5-HT细胞密度从十二指肠、空肠到回肠依次减少,至大肠又显著升高（P〈0．01）。5-HT细胞形态多样,主要有圆形、椭圆形和锥形,肠上皮中锥形5-HT细胞通过顶部较长的胞突通向肠腔,基部较宽的胞体与固有层相接触。结论中国穿山甲消化道5-HT细胞的分布和形态同其它动物有相似之处,也有其自身特点。中国穿山甲消化道中5-HT细胞的分布与其食性是相适应的。     

移植的5—羟色胺能神经元跨软脊膜迁入大鼠脊髓的研究

本文对移植的5-HT神经元从蛛网膜下腔跨软脊膜迁移进入脊髓作了初步研究。将含有5-HT细胞的胚胎中缝核组织小块或神经细胞悬浮液作为移植物,以5-HT免疫组织化学方法跟踪移植细胞,结果如下:(1)在低胸水平横切脊髓,10d后,横断脊髓内的5-HT纤维消失。(2)横切脊髓(方法同上)后,立即将中缝核组织小块移植在胸腰段脊髓的蛛网膜下腔,一月后.在横断脊髓内出现5-HT阳性神经元和纤维。5-HT纤维能在灰白质内延伸。(3)脊髓横断后,若以中缝核的细胞悬浮液代替组织小块,作上述移植,则在移植区附近的灰质内出现大量的5-HT阳性神经元。这些神经元在灰质内的分布范围与神经细胞悬浮液在蛛网膜下腔的移植范围相一致。迁入神经元能在灰质内重新形成5-HT阳性纤维网。(4)经上述移植后,灰质内出现的5-HT阳性纤维随远离细胞体而变得稀疏。白质内的5-HT阳性纤维远比灰质内稀少。本实验结果表明:移植在脊髓蛛网膜下腔的脑干5-HT细胞能跨软脊膜迁移进入脊髓。     

脊髓培养神经元中微管相关蛋白-5的分布及可塑性

用新生 Wistar大鼠进行脊髓神经元培养 ,研究微管相关蛋白 - 5与其单克隆抗体结合后的分布情况。使用微管解聚药 nocodazole处理神经元 ,应用免疫组织化学染色来观察微管相关蛋白 - 5的改变。另一组神经元使用 nocodazole处理后再用 PMA处理 ,观察微管相关蛋白 - 5及神经元的改变。结果表明 ,微管相关蛋白 - 5在胞浆及突起中均有分布 ,并随着培养天数的递增而递减。使用 nocodazole后神经元中微管相关蛋白 - 5的分布及数量明显减少。PMA处理神经元后尽管使微管相关蛋白 - 5的正常结构被破坏 ,而神经元的伸展却不受影响     

5—羟色胺介导的豚鼠肠系膜下神经节突触传递

本实验通过豚鼠离体肠系膜下神经节(IMG)的细胞内生物电记录方法观察到:(1)5-羟色胺(5-HT 1-100μmol/L)灌流可在部分 IMG 细胞引起与非胆碱能迟慢兴奋性突触后电位(Is-EPSP)相似的缓慢去极化;(2)持续灌流5-HT 可使对5-HT 敏感的 IMG 细胞的Is-EPSP 明显阻抑;(3)5-HT 去极化及5-HT 敏感细胞的 Is-EPSP 均可为5-HT 再摄取抑制剂氟苯氧丙胺(50μmol/L)所增大,而对5-HT 不敏感细胞的 Is-EPSP 则不受这种药物的影响,(4)5-HT 合成抑制剂对氯苯丙氨酸(PCPA)预处理可使 IMG 细胞的 Is-EPSP 的出现率和去极幅度均明显减低。上述结果表明:5-HT 可能参与介导豚鼠部分 IMG 细胞的Is-EPSP。     

用TnV分离粘细菌发育回复突变株

fruA∷TcΩ5 is a development deficient strain of M.Xamthus.Transposon TnV was used to randomly mutagenize various sites of fruA ∷TcΩ5 chromosome.Fruiting body formation was restored in one TnV insertion mutant,designated XM1206.The TnV\|inserted DNA fragment from XM1206 chromosome was cloned,which may be served as a probe to isolate the corresponding allele from wild\|type strain.     

大鼠脑内5-羟色胺在应激性溃疡形成中的作用

通过神经化学和神经药理学的方法,在大鼠观察了冷冻加束缚应激性溃疡的形成过程中,脑内5-羟色胺(5-HT)的作用。结果如下:1.在应激过程中,脑内5-HT 及其主要代谢产物5-羟吲哚乙酸(5-HIAA)的含量明显升高,特别是5-HIAA 的含量随着应激时间的延长持续上升,说明5-HT 的代谢加快。2.脑内5-HT 或5-HIAA 含量在应激45min 时与溃疡指数呈明显的负相关,而在应激180min 时则与溃疡指数呈明显的正相关。3.侧脑室注射5-HT或其前体5-羟色氨酸(5-HTP),对应激性溃疡的形成呈双重作用,小剂量时减轻而大剂量时加重溃疡的形成。4.腹腔注射5-HT 合成阻断剂对氯苯丙氨酸(pCPA)可降低大鼠脑内5-HT 和5-HIAA 含量,使应激60min 鼠的溃疡形成加重,而使应激180min 鼠的溃疡形成减轻。以上结果提示,在大鼠的冷冻加束缚应激性溃疡的形成过程中,脑内5-HT 起着一定的作用,它很可能在应激早期减轻而在应激晚期加重溃疡的形成。     

炎症介质对离体大鼠肠系膜动脉降钙素基因相关肽释放的影响

本工作目的是在离体大鼠肠系膜动脉床灌流模型上,观察几种常见炎症介质：前列腺素Ｅ２（ＰＧＥ２）、缓激肽（ＢＫ）、组胺（ＨＩＳ）、血小板活化因子（ＰＡＦ）及５－羟色胺（５－ＨＴ）对血管周围感觉神经介质ＣＧＲＰ释放的直接影响。结果显示：ＰＧＥ２（１－１００μｍｏｌ／Ｌ）和ＢＫ（５－１０μｍｏｌ／Ｌ）能引起大鼠肠系膜动脉床时间和浓度依赖性地释放ＣＧＲＰ。ＨＩＳ,ＰＡＦ和５－ＨＴ则未见明显作用。结果提示,ＰＧＥ２与ＢＫ可能是引起血管周围感觉神经兴奋和ＣＧＲＰ释放的主要炎症介质。     

POSTSYNAPTIC ADRENERGIC-CYCLIC AMP CONTROL OF THE SEROTONIN CONTENT OF CULTURED RAT PINEAL GLANDS

Abstract— This investigation was designed to determine whether the amount of serotonin (5-HT) in cultured pineal glands can be altered by norepinephrine (NE). Treatment with l -NE (10^?5-10^?7m ) for 4-6 h caused a gradual decrease in the concentration of 5-HT to a value that was less than 30% of that in the untreated control gland. This effect was observed using chronically denervated pineal glands. d -Norepinephrine (10^?6-10^?7m ) and dopamine (10^?4m ) were ineffective in lowering 5-HT. The effect of l -NE was completely blocked by a β-adrenergic receptor blocker, propranolol and was only slightly decreased by α-adrenergic receptor blockers. These observations indicate that l -NE acts post-synaptically via a highly specific β-adrenergic mechanism. The effect of l -norepinephrine was mimicked by theophylline and N⁶, 2′0-dibutyryl adenosine 3′,5′-monophosphate, an indication that adenosine 3′,5′-monophosphate is involved in the effect of l -NE on 5-HT. Treatment with cycloheximide, which by itself caused a decrease in pineal 5-HT, also blocked any further decrease caused by treatment with l -NE, an indication that protein synthesis is necessary for maintenance of baseline levels of serotonin and for the effect of l -NE to be observed. The total amount of l -[³H]NE and degradation products of L-[³H]NE in the gland after 6 h of treatment with l -[³H]NE was less than 3 pmol. This amount of l -NE and degradation products of l -NE could not account for the decrease of 100-200 pmol of 5-HT on the basis of a mole for mole replacement of 5-HT by l -NE. These findings are consistent with the hypothesis that non-neuronal pineal 5-HT is physiologically regulated by the release of l -NE from the sympathetic nerve network.     

KINETICS OF NEUTROPHILIC GRANULOCYTES IN THE BLOOD OF RATS

The kinetics of neutrophilic granulocytes in the blood of rats were investigated using in vivo ³H-TdR labelling and autoradiography. The radioactive precursor was administered by single injection, repeated injections at 5 hr intervals and continuous infusion. The appearance of labelled granulocytes in the blood and in the sputum was recorded up to 120 hr after tracer application. In contrast to results after a single injection of ³H-TdR, complete labelling of the blood granulocyte pool was achieved when the DNA precursor was given by continuous infusion or four repeated injections at 5 hr intervals. In the latter experiments, an exponential replacement of unlabelled blood granulocytes by labelled granulocytes could be demonstrated, the mean intravascular half-life being 5·7 hr. This figure is in good agreement with values obtained by isotopic techniques in other mammalian species.     

INHIBITORY EFFECT OF 5-BROMOURACIL AND 5-FLUOROURACIL ON PHOTOPERIODICALLY INDUCED GERMINATION OF ERAGROSTIS SEED

1. The inhibitory effects of 5-bromouracil and 5-fluorouracil onthe photoperiodically induced germination of Eragrostis ferrugineaseed were investigated. 5-BU was more effective than 5-FU ininhibiting germination, but less effective in suppressing seedlingelongation.
2. The inhibition of germination by 5-BU was specificallyex ertedon the inductive dark process, which i9 essential tothe photoperiodicgermination induction. A high concentration(10^–1:M) of5-FU also elicited a complete inhibition ofgermination. 5-FU,however, did not affect the photoperiodicinduction processes,but inhibited the processes subsequentto them. The inhibitionof germination by 5-BU or 5-FU was alleviatedby neither uracil,thymidine nor orotjc acid.
3. The 3eedlinggrowth was effectively inhibited by 5-FU, and theinhibitionwas reversed by uracil, uridine and orotic acid,but not bythymine and thymidine. The effect of 5-FU may, therefore,possiblybe by virtue of its depressing action upon ribonucleicacidsynthesis.

(Received April 18, 1963; )     

小鼠4.5S RNA逆转座子对Luc基因表达的影响

利用ＲＴ－ＰＣＲ方法,从小鼠肝脏组织总ＲＮＡ中扩增出４．５ＳＲＮＡ的ｃＤＮＡ。该ｃＤＮＡ被克隆到ｐＧＥＭ３Ｚｆ（＋）质粒上,酶切鉴定并测序。然后将该序列插入以Ｌｕｃ基因作为报道基因的表达载体ｐＳＶｌｕｃ２０的ＰｖｕⅡ位点,构建了含４．２ＳＲＮＡ逆转座子的表达载体ｐＳＶｌｕｃ２０－４．５Ｓ。脂质转染法将表达载体导入小鼠骨髓瘤细胞ＮＳ－１、ＳＰ２／０和人乳腺癌细胞Ｂｃａ６１。结果表明,小鼠４．５ＳＲＮ