Axonal and myelin lesions inβ-mannosidosis: Ultrastructural characteristics

Summary Ultrastructural changes in central nervous system (CNS) white matter of three goats affected with-mannosidosis were analyzed to further define characteristics and pathogenesis of axonal and myelin abnormalities. The variations in myelin association and contents of axonal spheroids were delineated. The occurrence of spheroids in a 96/150-day fetus documented the early development of these axonal lesions. In regions of severe myelin deficits, the presence of apparently normal axons and a reduction in the number of oligodendrocytes were confirmed. Many remaining cells in myelin-deficient regions were characterized by dark, vacuolated cytoplasm. The occurrence of internodes with myelin sheaths adjacent to internodes without myelin sheaths suggested that an axonal defect is not primarily responsible for the absence of myelin sheaths. A mild myelin deficit in the spinal cord was indicated by the presence of unmyelinated axons. Except for occasional mild cytoplasmic vacuolation, the spinal cord glial cells appeared relatively normal. The findings presented here are consistent with the hypothesis that an oligodendrocyte defect, expressed by regional differences, is a major factor in the pathogenesis of myelin deficiency in-mannosidosis.Supported by NIH grant NS-16886 to MZJ and BRSG funds from the College of Osteopathic Medicine, Michigan State University, to KLL     

Endogenous dopamine release from tuberoinfundibular neurons: Does calmodulin play any role?

Summary The possible involvement of calmodulin in the process of endogenous dopamine (DA) release from arcuateperiventricular nuclei-median eminence fragments, containing tuberoinfundibular dopaminergic (TIDA) neurons, has been investigated in an in vitro incubation system. For this purpose the basal and K⁺-stimulated DA release was examined in the presence and in the absence of the different putative calmodulin antagonists, pimozide, trifluoperazine, penfluridol and N-(6-aminohexyl)-5-chloro-1-naphthalene-sulfonamide (W-7).Trifluoperazine and pimozide in concentrations up to 100 M were both uneffective in blocking K⁺-evoked DA release. Penfluridol in doses of 5 and 10 M, did not prevent 35 mM K⁺-induced endogenous DA release. It was able to reduce K⁺-stimulated DA release only at the very large concentration of 100 M.W-7 added in vitro to the hypothalamic fragments, prevented endogenous DA release evoked by 35 mM K⁺ in a dose-dependent manner. W-5, a chlorine deficient analogue of W-7, that interacts only weakly with calmodulin, failed to modify K⁺-stimulated endogenous DA release in doses up to 200 M.All the putative calmodulin antagonists used in the present study did not induce any change of basal DA release.IN conclusion the fact that most of the agents, except W-7, known to antagonize calmodulin-dependent processes in many biological systems failed to interfere with the release of endogenous DA from TIDA neurons seems to suggest that calmodulin does not play a crucial role in the process of DA release and that the inhibitory effect of W-7 on endogenous DA release may be better attributed to other mechanisms different from its anticalmodulin action.     

Rapid hydroxylation of methtryptoline (1-methyltetrahydro-β-carboline) in rat: Identification of metabolites by chiral gas chromatography-mass spectrometry

Summary Racemic methtryptoline (1-methyltetrahydro--carboline) and 5-hydroxymethtryptoline-9-carboxylic acid (6-hydroxy-1-methyltetrahydro--carboline-1-carboxylic acid) were administered intraperitoneally to rats and the components of their urine was subsequently investigated by chiral gas chromatography-mass spectrometry. Methtryptoline rapidly became hydroxylated in the 5- and 6-position and excreted in urine. There was about a ninefold predominance of the S(–) enantiomer over the other in the 5-hydroxylated species, while the 6-hydroxylation produced a small excess of the R(+) enantiomer. About 75% of the injected dose of methtryptoline was recovered in the urine as 5- and 6-hydroxylated compounds during the first 24 h period, demonstrating that hydroxylation represents the major metabolic pathway. Treatment with 6-hydroxymethtryptoline-9-carboxylic acid led to a fivefold increase in the urinary excretion of 5-hydroxymethtryptoline during the first 24 h period with a predominance of the S(–)-enantiomer, indicating a much smaller conversion rate than from methtryptoline. It was concluded that hydroxylation of methtryptoline is a likely pathway for the natural formation of 5-hydroxymethtryptoline.     

Influence of age on serum protein binding of propranolol

Summary The extent of propranolol protein binding was determined in three different age groups of healthy drug-free caucasian males. Volunteers selected for study were 6–15 years old, 25–36 years old and 68–76 years old. Ten milliliters of blood were obtained via venipuncture and collected in glass tubes from the subjects after an overnight fast. Binding determinations were performed by equilibrium dialysis using radiolabelled propranolol. Serum albumin and ₁-acid glycoprotein concentrations were determined in all subjects by radial immunodiffusion. The results obtained showed wide intersubject variability in the binding ratio of propranolol and serum concentrations of ₁-acid glycoprotein. Mean albumin serum concentration was found to be significantly lower in the elderly group as compared to the adult and pediatric groups (p<0.02). A positive correlation was found between the binding ratio of propranolol and the serum concentration of ₁-acid glycoprotein in all the subjects (r=+0.66,p<0.005). No significant correlation was found between the binding ratio of propranolol and the serum concentration of albumin (r=–0.03,p<0.88). These data suggest that the extent of propranolol binding is influenced primarily by serum concentrations of ₁-acid glycoprotein and not by differences in age.     

Huntington's disease: biochemical prediction by determination of GABA synthesis of cultured fibroblasts

Summary GABA synthesis in skin fibroblasts from patients with Huntington's chorea was compared with that in a control group by means of the highly specific ³H-muscimol radioreceptor assay. A significantly increased rate of GABA synthesis was found in the group with Huntington's chorea in an early cell passage. The possible use of this method for early diagnosis of Huntington's chorea is considered.

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Zusammenfassung Die GABA-Synthese in Hautifbroblasten von Chorea Huntington-Patienten im Vergleich zu einer gesunden Kontrollgruppe wurde mittels des hochspezifischen ³H-Muscimol-Radiorezeptoren-Assays untersucht. Wir fanden eine signifikante 8fache Erhöhung der GABA-Synthese bei Chorea Huntington in einer frühen Zellpassage. Es wird erwogen, diese Methode zur Frühdiagnostik von Chorea Huntington einzusetzen.

     

河北汉族人群D7S21位点DNA多态性研究

目的探讨D7S2 1位点在河北汉族人群分布的多态性 ,为DNA指纹数据库的构建及其法医学应用提供基础资料。方法应用MVR PCR方法和聚丙烯酰胺梯度凝胶电泳银染法对 12 4名河北汉族人群无关个体D7S2 1位点进行了快速检测 ,并进行数字编码。结果每一个体平均得到 3 6个数字编码 ,未发现任何两个无关个体所有编码相同 ,两无关个体 3 6个编码相同的机率为 3 .4 8× 10 -18。三种重复单位a 型、t 型和o 型出现的机率分别为 4 8.5 %、4 9.5 %和 2 .1%。该位点杂合度为 0 .9876,非父排除率为 0 .974 6,多态性信息含量为 0 .9872。结论D7S2 1位点在河北汉族人群中具有高度的多态性 ,聚丙烯酰胺梯度凝胶电泳银染法简便、快速 ,具有一定的实用价值     

7-氯苄基四氢巴马汀对大鼠心肌肥厚及左心室肌原纤维Ca~(2 )-Mg~(2 )-ATP酶活力的影响

目的观察 7-氯苄基四氢巴马汀 ( 7-chlor -BTHP)对大鼠心肌肥厚和心室肌原纤维质膜Ca2 -Mg2 -ATP酶活力的影响。方法用L -甲状腺素诱发大鼠心肌肥厚 ,然后观察 7-chlor -BTHP对大鼠心肌肥厚及左心室肌原纤维Ca2 -Mg2 -ATPase的影响 ,以普萘洛尔 (Pro)作为阳性对照。结果经过 7-chlor-BTHP治疗 3天后 ,心肌肥厚明显改善 ,Ca2 -Mg2 -ATPase活力明显降低。结论 7-chlor-BTHP能明显消退L -甲状腺素诱发的大鼠心肌肥厚 ,并能显著降低心室肌原纤维膜Ca2 -Mg2 -ATPase酶活力。     

成年起病脊肌萎缩症SMN基因外显子7缺失的初探

目的探讨成年起病的脊肌萎缩症(SMA)患者的运动神经元存活基因SMN的缺失情况。方法用聚合酶链反应-酶切技术对15例SMA病人及33例正常对照的外显子7进行检测,明确有无缺失。结果3例SMA的SMN基因外显子7纯合缺失,其余12例和对照组均阴性。结论SMN基因外显子7缺失可作为成年起病SMA的辅助诊断,以提示SMA遗传的异质性。     

不同烧结温度对双相钙磷陶瓷颗粒材料介孔结构及其成骨性能的影响

目的通过体内外实验检测不同烧结温度下制备的不同介孔直径双相钙磷陶瓷（biphasic calcium phosphate，BCP）颗粒材料成骨能力差异，为筛选具备更好临床应用参数的 BCP 材料提供依据。方法将羟基磷灰石（hydroxyapatite，HA）及 β-磷酸三钙（β-tricalcium phosphate，β-TCP）以 8∶2 比例混合后，分别在 1 050、1 150 及 1 250℃ 下烧制 3 h 制备 3 种 BCP 材料（分别设为材料1、2、3），比表面积测试法（Brunauer-Emmett-Teller test，BET）测量材料的颗粒内部孔隙率及介孔直径、体积、面积，X 线衍射（X-ray diffraction，XRD）评估材料组成成份，扫描电镜观察材料微观表面形态。体外将第 3 代 SD 大鼠 BMSCs 与各材料共培养 7 d（分别设为 A、B、C 组），扫描电镜观察细胞黏附情况，鬼笔环肽染色观察 BMSCs 贴附于材料表面后的形态，细胞计数试剂盒 8 法检测细胞增殖活性。体内建立比格犬异位成骨模型：取 9 只比格犬，于每只犬双侧竖脊肌内制作 9 个肌袋，将肌袋随机分为 3 组（每组 3 个/只），A、B、C 组分别置入材料 1、2、3。术后 1、2、3 个月分别麻醉 3 只比格犬取材行 HE、Masson 及番红固绿染色，计算 BCP 间隙中的成骨面积比；行实时荧光定量 PCR（real-time fluorescence quantitative PCR，qRT-PCR）检测成骨相关基因 ALP、骨桥蛋白（osteopontin，OPN）、骨钙素（osteocalcin，OC）的表达。结果BET 检测示随烧结温度增加，颗粒内部孔隙率无明显变化，但介孔直径、体积及面积逐渐减小；XRD 检测示 3 种材料均可见 HA 及 β-TCP 两种 X 线衍射波；扫描电镜观察示 3 种材料表面有广泛分布的微孔，孔间有空隙相连。体外实验示 BMSCs 在 3 种材料表面黏附、增殖，B、C 组材料的细胞生物相容性优于 A 组。体内实验结果示，术后 2 个月开始 3 种材料颗粒孔隙内即可见明显的骨样组织沉积。各组成骨面积比随时间延长均增加，术后 2、3 个月 A 组成骨面积比显著高于 B、C 组，1 个月时显著高于 B 组（P<0.05）。qRT-PCR 检测示，A 组成骨相关基因表达在 2 个月时出现峰值，B、C 组各成骨相关基因表达随时间延长逐渐增加。术后 1 个月 A 组 ALP 和 OPN mRNA 相对表达量显著高于 B、C 组，术后 2 个月 A 组 OC mRNA 相对表达量显著高于 B、C 组，术后 3 个月 B、C 组 ALP mRNA 相对表达量及 B 组 OPN mRNA 相对表达量显著高于 A 组（P<0.05）；其余各时间点各组间比较各基因 mRNA 相对表达量差异均无统计学意义（P>0.05）。 结论不同烧结温度下制备的 BCP 材料，其介孔直径随温度增加而减小。不同介孔直径的 BCP 材料异位成骨能力存在差异，其中直径为 12.57 nm 的 BCP 材料能更早激活成骨基因，具备更强的成骨能力。介孔直径可作为一个优化 BCP 材料成骨能力的指标。