EFFECT OF TRANQUILIZERS ON REGIONAL DISTRIBUTION OF ASCORBIC ACID IN THE RAT BRAIN

—Studies were made of the effects of fluphenazine, chlorpromazine and triflupromazine on tissue concentration, liver synthesis of ascorbic acid and its distribution in different areas of the brain. All the three drugs were found to increase liver concentration and synthesis of the vitamin at 24 hr after administration of a single oral dose of the vitamin, but only fluphenazine was found to increase its concentration in the adrenals and brain; the increase in the latter case was found to vary in different regions of the brain, the olfactory lobes, hypothalamus and residual brain showing maximum increases, andthe basal ganglia, visual cortex and remaining dorsal cortex showing minimum increases. The effects were found to be reversed 72 hr after drug treatment.     

EFFECT OF UNDERNUTRITION ON AMINO ACID COMPARTMENTATION IN THE DEVELOPING RAT BRAIN

—Rat pups undernourished through 21 days of age show abnormal patterns of cerebral amino acid metabolism. The pattern of incorporation of radioactivity from l -[U-¹⁴C]leucine into amino acids derived from tricarboxylic acid cycle intermediates was altered, with significantly more ¹⁴C being incorporated into glutamate and aspartate in the underfed rats than in controls. Glutamate compartmentation, manifested in the ratio of specific radioactivities of glutamine to glutamate, developed more slowly in the. diet-restricted group. These results are similar to those seen in neonatally-thyroidectomized rats and suggest decreased growth of neuronal processes. This impairment of amino acid metabolism returns to normal after a 7-week period of adequate nutrition.     

EFFECT OF PYRIDOXINE DEFICIENCY ON AROMATIC l-AMINO ACID DECARBOXYLASE IN THE DEVELOPING RAT LIVER AND BRAIN

—Maternal pyridoxine deficiency begun 2 weeks before mating and continued throughout pregnancy and the nursing period resulted in diminished wt. gains in the brain, the liver and the body in the first 16 days of life, as well as lowered levels of the aromatic l -amino acid decarboxylase in both brain and liver tissue. The fetus was protected from the effect of vitamin B₆ deficiency during pregnancy, since at birth the body wt., organ weights, and decarboxylase levels in these tissues were comparable to those of control litters. The brain was affected less than the liver, both in rate of wt. increase and decarboxylase activity. The cerebellum normally developed measurable decarboxylase activity only during the second week of life. The cortex normally slowly increased its low decarboxylase activity during the first week postnatally, with a more rapid increase during the second week. This rapid increase was primarily in the holoenzyme moiety. The rest of the brain, which had well developed levels of decarboxylase activity at birth, normally showed a sharp increase during the second week of life which was also largely in the holoenzyme portion. When the increasing weights of these tissues were considered, it became obvious that the total amount of apoenzyme as well as the amount of holoenzyme were increasing in the normally developing rat, although the greatest amount of the change was in the holoenzyme form. The liver normally showed a much more rapid increase in decarboxylase activity than did the brain, and showed the increase much earlier. The holoenzyme normally increased rapidly after the first 4 days, whereas the apoenzyme concentration levelled off at this time. The effect of the pyridoxine deficiency on decarboxylase activity was almost entirely on the holoenzyme form of the decarboxylase, since the apoenzyme form generally remained the same in the control and the deficient pups during development. There appeared to be no decarboxylase inhibitor present in pyridoxine deficient tissues, nor any evidence in control tissues for an enzyme required for the activation of the decarboxylase by cofactor.     

THE EFFECT OF PHENYLALANINE AND ITS METABOLITES ON GLUCOSE UTILIZATION IN DEVELOPING BRAIN

Abstract— High concentrations of phenylalanine, o -tyrosine, and phenylpyruvic acid do not modify the ability of immature rabbit brain to utilize glucose for support of respiration or for oxidative decarboxylation.     

INTERRELATIONS BETWEEN POLYAMINES AND NUCLEIC ACIDS: CHANGES OF POLYAMINE AND NUCLEIC ACID CONCENTRATIONS IN THE DEVELOPING RAT BRAIN

The rat brain concentrations of protein, RNA, DNA, putrescine, and of the polyamines spermidine and spermine, were studied during development. Putrescine formation is apparently controlled by ornithine decarboxylase. Spermidine and spermine concentrations change in inverse directions to their anabolic enzymes. It has been presumed, therefore, that the low concentrations of the polyamine-synthesizing enzymes in immature brain are compensated for, by high putrescine and S-adenosylmethionine concentrations. In agreement with previous findings for fish brain, the changes in RNA and spermidine concentrations were most closely correlated. The functions of DNA: spermine are directly correlated only during the periods of brain maturation, after cell proliferation has nearly ceased.     

THE EFFECT OF DELTA-AMINOLAEVULINIC ACID ON THE UPTAKE AND EFFLUX OF AMINO ACID NEUROTRANSMITTERS IN RAT BRAIN SYNAPTOSOMES

Abstract— δ-Aminolaevulinic acid (δ-ALA) is an omega amino acid structurally similar to γ-aminobutyric acid (GABA) and l -glutamate. We have examined the effect of δ-ALA on the uptake and efflux of radiolabelled GABA and l -glutamate in rat cortical synaptosomes and report: (1) low concentrations of δ-ALA reduced the potassium-stimulated release of [³H]GABA from the synaptosome preparation. This effect was reversed by the GABA receptor antagonist bicuculline. We postulate that GABA release is modulated by a feedback mechanism on presynaptic GABA receptors, and that δ-ALA has agonist activity at these receptors. (2) δ-ALA at high concentrations (0.75-5.0 m m ) stimulated the efflux of l -[¹⁴C]glutamate from preloaded synaptosomes. (3) δ-ALA had no effect on potassium-stimulated release of l -glutamate. (4) Uptake of labelled l -glutamate was inhibited by δ-ALA in a noncompetitive fashion. (5) Synaptosomes did not accumulate [¹⁴C]δ-ALA in the range 0.5-50 δ m . These results are discussed in relation to the control of GABA release from nerve endings, and the role of δ-ALA in the neuropsychiatric manifestations of the acute porphyric attack.     

低温胁迫对水稻幼苗抗坏血酸含量的影响

随着低温时间的延长,水稻幼苗抗坏血酸和GSH的含量均平行地下降,抗坏血酸含量与电解质渗出率之间呈负相关。增强低温胁迫程度,随着抗坏血酸含量逐渐减少,MDA含量则逐渐增加。经低温处理后在不同光强下恢复时,抗坏血酸和MDA含量的变化不同。抗氧化剂(GSH、半胱氨酸和巯基乙醇)的预处理可抑制低温引起的抗坏血酸含量的下降。     

缺乏抗坏血酸对豚鼠胆固醇代谢的影响

边缘性缺乏抗坏血酸之豚鼠,于三周内其肝脏及小肠粘膜3-羟-3-甲基戊二酰辅酶A还原酶(HMGR)活力均下降到原有水平的50％,但肝脏胆固醇7α-羟化酶活力尚无显著性改变。坏血病豚鼠(三周内)上述几种酶活力都下降至原有水平的50％左右。豚鼠摄取抗坏血酸不足,其血清总胆固醇浓度显著增加,而血清高密度脂蛋自胆固醇浓度显著减少,其改变程度与抗坏血酸缺乏状况一致。     

THE EFFECT OF GROWTH AND DEVELOPMENT ON THE PHOSPHOLIPIDS OF THE HUMAN BRAIN

Abstract— The phospholipid content and composition of the different regions of the developing human brain were studied. Brains from 25 fetuses and 9 infants, aged 13 weeks gestation to 26 months, were analysed. The concentration of total lipid-P was highest in the brain stem and lowest in the cerebellum at any age. Compared with the forebrain or brain stem, the cerebellum had a sharp phospholipid growth spurt between 3 months before and 6 months after birth. Before birth, the phospholipid pattern was similar in each part of the brain, with choline phosphoglycerides as the major phospholipid. After birth, the pattern in the brain stem changed further and ethanolamine phosphoglycerides became the dominant phospholipid, while in the other two there was little change. In all parts of the brain the proportion of sphingomyelin increased. The relative proportion of serine and inositol phosphoglycerides remained almost constant throughout the whole period of development. The possible significances of the changes in the phospholipids in neurological development are discussed.     

THE EFFECT OF AMINO-OXYACETIC ACID ON BRAIN CATECHOLAMINES

Abstract— —Administration of amino-oxyacetic acid (AOAA) to rats induced a pronounced decrease of midbrain norepinephrine (NE) and adrenal epinephrine (E) after 30 min, at which time the GABA level of midbrain had increased to 117 per cent of the initial value. The concentrations of NE in the pons-medulla and of dopamine (DA) in the cerebral hemispheres were not changed.
Further increases in brain GABA were accompanied by a rise of NE in midbrain and pons-medulla beginning 1 hr after AOAA administration. A rise of cerebral DA level was observed only after 4 hr. Six hours after AOAA administration the levels of both NE and DA in brain were reduced.
From the results of these and other studies, where administration of small amounts of GABA were shown to affect brain NE and serotonin levels, it is suggested that monoamines may be involved in the physiological action of GABA in the brain.     

镉对蒜根生长的毒害及抗坏血酸、铁盐的解毒效应

蒜鳞茎在不同浓度的Ｃｄ溶液中处理２４－４８ｈ,观察到随着Ｃｄ浓度的递增或培养时间的延长,根的增长速率递减或停止,根尖细胞有丝分裂指数下降,分裂细胞异常率增 裂细胞异常主要表现为低毒时,染色体的Ｃ－有丝分裂,染色体桥以及高毒时,染色体粘连,断裂,核解体等。     

天然药物对血链球菌生长和产酸影响的体外研究

目的：通过研究不同天然药物对血链球菌生长及产酸的影响,为今后筛选出能有效调理口腔菌群生态平衡的药物奠定基础。方法：选用变形链球菌SB179作为实验菌株,测定川芎,血藤,五倍子等11种天然药物的最低抑菌浓度MIC,再以低于MIC的4个浓度配制含药的TPY液体培养基,调定其初始pH为7．4,接种血链球菌,厌氧培养后测定其终末pH,结果：当药物浓度低于或等于8．000mg/ml时,各天然药物对血链球菌的生长均有一定的抑制作用,且以五倍子作用较强,槟榔,茶多酚,蜂房,大黄,三七,血藤,白芷对血链球菌的产酸具有一定的抑制能力,而黄芩,川芎,五倍子和儿茶没有明显的抑制作用,结论：槟榔,茶多酚,蜂房,大黄,三七,血藤和白芷对血链球菌的生长和产酸都有一定的抑制作用.     

天然药物对唾液链球菌生长与产酸影响的体外研究

目的：通过研究不同天然药物对唾液链球菌生长及产酸的影响,为今后筛选出能有效调理口腔菌群生态平衡的药物奠定基础,方法：选用唾液链球菌SS196作为实验菌株,测定川芎,血藤,五倍子等11种天然药物的最低抑菌浓度MIC,再以低于MIC的4个浓度梯度配制含药的TPY液体培养基,调定其初始pH为7．4,接种唾液链球菌,厌氧培养后测定其终末pH,结果：当药物浓度低于或等于8．00mg/ml时,除槟榔,蜂房,三七外,其他药物对唾液链球菌的生长都有一定的抑制作用,且以大黄,五倍子和黄芩较强,槟榔,茶多酚,大黄,蜂房,黄芩,三七,五倍子和儿茶对唾液链球菌的产酸具有一定的抑制能力,而白芷,川芎和血藤没有明显的抑制能力,结论：茶多酚,大黄,黄芩,五倍子和儿茶对唾液链球菌的生长和产酸都有一定的抑制作用。     

氮源及其浓度对三角褐指藻生长和脂肪酸组成的影响

为了研究氮源的类型和浓度对微藻脂肪酸组成的影响 ,用含有不同浓度NO3 -、NH4 、NH2 CONH2 的培养基 ,对三角褐指藻 (Phaeodactylumtricornutum)进行了培养 ,并测定了其生长和脂肪酸组成。结果表明 ,培养基中不添加氮源时 ,三角褐指藻生长缓慢 ,但多不饱和脂肪酸 (PUFAs)和C18脂肪酸 (C18∶0 ,C18∶2 (n -6) ,C18∶3 (n -6) )占总脂肪酸的比例较高 ;氮浓度较低 (<1 8mmol/L)时 ,三角褐指藻以NH4 为氮源 ,生长较快 ;氮浓度较高 (>3 5mmol/L)时 ,以NH2 CONH2 为氮源 ,生长较快。以NH4 或NH2 CONH2 为氮源时 ,EPA(Eicosapentaenoicacid)和PUFAs占总脂肪酸的比例随着其浓度的增加而上升 ;而以NO3 -为氮源时 ,EPA和PUFAs随着NO3 -浓度增加先上升后下降 ,最适NO3 -浓度为 1 8mmol/L ,此时的EPA占总脂肪酸的比例为 16 7%。EPA占干重 (w/w)的比例 ,不管是哪种氮源 ,均随着氮浓度的增加而升高 ,但是在 0 9— 3 5mmol/L之间 ,3种氮源间EPA含量差异不显著。当氮源浓度为 7 0mmol/L时 ,以NH2 CONH2 为氮源 ,EPA和PUFAs含量最高 ,分别为 2 6 %和 4 4 %。PUFAs占干重的比例随着NO3 -浓度增加而下降 ,随NH2 CONH2 浓度增加而升高 ,而受NH4 浓度变化的影响不显著。