A mutation in the heptad repeat 2 domain of MFN2 in a large CMT2A family

Dominant mutations in MFN2 cause a range of phenotypes, including severe, early‐onset axonal neuropathy, “classical CMT2,” and late‐onset axonal neuropathies. We report a large family with an axonal polyneuropathy, with clinical onset in the 20s, followed by slow progression.     

Rhabdomyolysis in pontocerebellar hypoplasia type 2 (PCH-2)

Pontocerebellar hypoplasia type 2, an autosomal recessive neurodegeneration with prenatal onset, is characterised by progressive microcephaly and chorea/dystonia and has not previously been associated with muscular involvement. The gene associated with PCH-2 is unknown. An episode of rhabdomyolysis is reported in two non-related children with PCH-2, fatal in one, precipitated by intercurrent disease. Muscle biopsies in two other PCH-2 patients, and in one rhabdomyolysis patient whose biopsy antedated this complication showed areas of myofibrillar disruption or necrosis. Postmortem muscle sampled in another case without neuromuscular symptoms revealed focal necrosis, regenerating small fibres and upregulation of HLA-ABC. Random serum creatine kinase values in six other PCH-2 patients without clinical signs of neuromuscular involvement were increased in four. Collected data provide preliminary evidence of a subclinical myopathy associated with PCH-2.     

Cholecystokinin-2 (CCK2) receptor-mediated anxiety-like behaviors in rats

Cholecystokinin (CCK) is a neurotransmitter in the brain closely related to anxiety. Of the two CCK receptor subtypes, CCK₂ receptors are most implicated in the control of anxiety-related behavior. CCK₂ receptor activation causes anxiogenic effects while the blockade of this receptor has anxiolytic effects. This review focuses on the molecular mechanisms of CCK₂ receptors underlying anxiety-related behaviors of PVG hooded and Spraque–Dawley (SD) rats in two anxiety models (elevated plus-maze [EPM] and cat exposure test). PVG hooded rats showed prolonged freezing behavior in the cat exposure test while SD rats showed very low levels of freezing. A CCK₂ receptor antagonist (LY225910) attenuated freezing behavior in PVG hooded rats while a CCK₂ receptor agonist (CCK-4) increased freezing behavior in SD rats. In contrast, the two strains behaved similarly on the EPM. CCK-4 caused a pronounced anxiogenic effect in PVG hooded rats but only a slight effect in SD rats. CCK₂ antagonists also showed more pronounced anxiolytic effects in PVG hooded rats than in SD rats. CCK₂ receptor expression was greater in PVG hooded than in SD rats in the cortex and hippocampus. Genetic studies also demonstrated four differences in the DNA sequence of the CCK₂ receptor gene between the two rat strains.     

缝线诱导大鼠角膜血管新生过程中环氧化酶2和基质金属蛋白酶2的表达

背景：研究表明环氧化酶2和基质金属蛋白酶2在角膜新生血管的发生中起重要作用,但其具体机制及相互关系仍不明确。 目的：观察环氧化酶2和基质金属蛋白酶2在缝线法诱导的大鼠角膜新生血管中的表达,并分析其相关性,探讨角膜新生血管形成的有关机制。 方法：采用缝线法建立SD大鼠角膜新生血管模型,术后每日裂隙灯观察角膜新生血管的生长情况,并于1,4,7,14, 21 d取材,行免疫组化及RT-PCR检测环氧化酶2和基质金属蛋白酶2蛋白的分布及二者mRNA的相对表达量,并进行相关性分析。 结果与结论：角膜缝线后三四天可见明显从角膜缘伸入角膜的毛刷状小血管,垂直角膜缘切线方向,角膜缝线处水肿;7 d角膜新生血管生长旺盛,角膜水肿继续加重,14 d新生血管延伸到达或超过缝线位置,分支密集并互相吻合形成袢状血管;21 d角膜新生血管变细。免疫组化及RT-PCR显示环氧化酶2和基质金属蛋白酶2于缝线后表达逐渐增加,7 d 达高峰,以后随炎症细胞的减少而减弱,主要分布于炎症细胞胞质及新生血管内皮细胞,两种因子的表达在角膜新生血管中具有正相关性(r=0.981, P < 0.05)。证实炎症相关的角膜新生血管中环氧化酶2和基质金属蛋白酶2的表达增加,并且与新生血管的发生、发展密切相关。     

The roles of prostaglandin E2 and D2 in lipopolysaccharide-mediated changes in sleep

When living organisms become sick as a result of a bacterial infection, a suite of brain-mediated responses occur, including fever, anorexia and sleepiness. Systemic administration of lipopolysaccharide (LPS), a common constituent of bacterial cell walls, increases body temperature and non-rapid eye movement (NREM) sleep in animals and induces the production of pro-inflammatory prostaglandins (PGs). PGE₂ is the principal mediator of fever, and both PGE₂ and PGD₂ regulate sleep–wake behavior. The extent to which PGE₂ and PGD₂ are involved in the effect of LPS on NREM sleep remains to be clarified. Therefore, we examined LPS-induced changes in body temperature and NREM sleep in mice with nervous system-specific knockouts (KO) for the PGE₂ receptors type EP₃ or EP₄, in mice with total body KO of microsomal PGE synthase-1 or the PGD₂ receptor type DP, and in mice treated with the cyclooxygenase (COX) inhibitor meloxicam. We observed that LPS-induced NREM sleep was slightly attenuated in mice lacking EP₄ receptors in the nervous system, but was not affected in any of the other KO mice or in mice pretreated with the COX inhibitor. These results suggest that the effect of LPS on NREM sleep is partially dependent on PGs and is likely mediated mainly by other pro-inflammatory substances. In addition, our data show that the main effect of LPS on body temperature is hypothermia in the absence of nervous system EP₃ receptors or in the presence of a COX inhibitor.     

HLA-DR2 in childhood narcolepsy

A 6-year-old boy with behavioral changes was found to have clinical and electrographically defined narcolepsy. He has HLA-DR2 as do virtually all adult narcoleptics. This finding raises new diagnostic, etiopathogenetic, and future therapeutic issues.     

Focal amyotrophy in neurofibromatosis 2

Neurofibromatosis type 2 (NF2) is an autosomal dominant disorder characterised by bilateral vestibular schwannomas and other CNS tumours including meningiomas and spinal schwannomas. Occasionally, peripheral neuropathy occurs in these patients but this is the first report of focal amyotrophy. Clinical, electrophysiological, and imaging data from four NF2 patients seen at a specialist neurofibromatosis clinic over a 4 year period are described in whom symptomatic focal amyotrophy preceded the diagnosis of NF2. Two presented with wasting and weakness of a single muscle group, several years before NF2 was diagnosed. In one patient a mononeuritis multiplex was the presenting feature of NF2, and in one patient focal wasting and weakness developed after the diagnosis of NF2 was made. In none of the four cases could a focal peripheral nerve or root neurofibroma be identified despite extensive imaging with MRI, and the limitations of neuroimaging for identifying a structural cause in patients with NF2 with a focal peripheral nerve lesion is discussed. It is likely that NF2 may affect peripheral nerve structures in a manner distinct from a compressive schwannoma.     

Specific bindings of prostaglandin D2, E2 and F2 alpha in postmortem human brain

Binding activities specific for each of [3H]prostaglandin (PG) D2, E2 and F2 alpha were detected in the P2 fraction of the human brain homogenates. The bindings were time-dependent, saturable and of high affinity; Kd values were 30 nM for all the PG bindings. Regional distribution of these binding activities was determined by measuring specific bindings with 10 nM [3H]PG-D2, [3H]PG-E2 and [3H]PG-F2 alpha in the P2 fractions from 17 brain regions. The PG-D2 binding activity was high in the hypothalamus, amygdala and hippocampus followed by cerebellar nuclei, thalamus, nucleus accumbens and cerebral cortex. The PG-E2 binding sites were similarly concentrated in the hypothalamus and the limbic system, but, unlike the PG-D2 binding, no significant binding of [3H]PG-E2 was observed in cerebellar nuclei, cerebellar cortex and putamen. Compared with these two PG bindings, PG-F2 alpha binding activity was low in many areas, but significant binding was detected in the amygdala, cingulate cortex, cerebellar medulla, hippocampus, nucleus accumbens, midbrain and hypothalamus. These results suggest the presence and specific distribution of three distinct types of PG binding activities, i.e. specific binding of PG-D2, PG-E2 and PG-F2 alpha, in the human brain.     

β-Endorphin enhances interleukin-2 (IL-2) production in murine lymphocytes

Beta-endorphin has been reported to enhance T lymphocyte proliferation and cytolytic activity. In this report, it is demonstrated that β-endorphin enhances the production of the T cell lymphokine, interleukin-2, from mitogen-stimulated, unfractionated murine splenocytes, as well from a cloned T cell line. The enhancement is naloxone irreversible and dependent on the integrity of the C-terminal amino acids, though the N-terminal amino acids appear to contribute to the potency of the enhancement. The data suggest that β-endorphin interacts with a nonopioid receptor that has specificity characteristics similar to a nonopioid β-endorphin receptor described in the central nervous system.     

The meaning of H2O2 generation in carotid body cells for PO2 chemoreception.

The rat carotid body is able to generate H2O2 in type-I cells with the aid of an electron-transferring chain with cytochrome b as the major component as it can be detected by spectrophotometry as well as confocal laser-microscopy. This cytochrome b is reducible by hypoxia, but not by cyanide, indicating that it does not participate in the energy production by the respiratory chain. The carotid body possesses a glutathione peroxidase (GPO) which scavenges H2O2 and other organic hydroperoxides. The nervous chemoreceptor discharge can be inhibited by external application of hydroperoxides with a similar half maximal value (60-80 microM) as used to stimulate GPO. A hypothetical signal chain is described which suggests the involvement of cytochrome b as an O2 sensor in PO2 chemoreception of the carotid body and the degradation of H2O2 by glutathione to control the K(+)-conductivity of carotid body cells.     

Fluorescent Ca2+-indicator quin 2 as an intracellular Ca2+ antagonist in platelet reaction

Preincubation of fluorescent Ca2+-indicator quin 2 resulted in inhibition on platelet aggregation and secretion in the absence of extracellular Ca2+. And the mechanism of the inhibition was studied. The inhibition by quin 2 of thrombin stimulated aggregation and ATP secretion of human platelets was dose and incubation time dependent and the inhibition was overcome by an addition of CaCl2 to the suspending buffer. Combination of quin 2 and Ca2+-blockers exerted the complete inhibition of the reaction in the presence of extracellular Ca2+. The inhibitory effect was observed when the intracellular concentration of quin 2 exceeds 3 mM, regardless of the initial dose or the preincubation time. The cellular content of ATP was not reduced by loading platelets with quin 2 in the concentration which exerted an inhibitory effect on the platelet reaction. From these observations, it was postulated that the inhibition is due to chelation of intracellular Ca2+ by quin 2 and the application of this agent as an intracellular Ca2+ antagonist was proposed. Also, we discussed the limitations in the use of quin 2 system as an intracellular Ca2+ indicator.     

胶质瘤中MMP-2和TIMP-2的表达及意义

目的探讨MMP-2和TIMP-2与胶质瘤侵袭性及恶性表型之间的关系及其意义。方法采用Elivision二步免疫组织化学法染色观察MMP-2和TIMP-2在46例不同恶性度胶质瘤及10例正常脑组织中的表达并用德国LeicaQ550cw图像分析系统测其灰度值作为表达强度的量化指标。结果在对照组、低度及高度恶性胶质瘤中,MMP-2的阳性表达率分别为10%、63.6%和95.8%;在对照组、低度及高度恶性胶质瘤中,TIMP-2的阳性表达率分别为10%、36.3%和37.5%。MMP-2在Ⅰ、Ⅱ级和Ⅲ、Ⅳ级胶质瘤中平均灰度值分别为173.27±13.26和98.63±18.20;TIMP-2在Ⅰ、Ⅱ级和Ⅲ、Ⅳ级胶质瘤中平均灰度值分别为210.44±12.95和205.65±9.75。结论MMP-2表达随胶质瘤恶性程度增加而增强,可作为胶质瘤恶性表型及侵袭性指标之一。TIMP-2表达在正常脑组织及不同级别胶质瘤中无明显差异。MMP-2/TIMP-2的比值与胶质瘤侵袭性密切相关。     

Differential expression of Bcl-2-related proteins in differentiating NT2 cells

Although the role of Bcl-2-related proteins as regulators of the apoptotic process has been well documented, recent studies suggest that they might also be implicated in neuronal differentiation. We have studied by immunocytochemistry, Western blotting and RT-PCR the expression pattern of Bcl-xL, Bcl-2 and BAX in the in vitro model of neuronal differentiation constituted by retinoic acid (RA)-treated NTera-2/D1 (NT2/D1) cells. Whereas BAX level did not change significantly during the RA treatment, Bcl-xL level increased markedly during the first week, before returning to basal level during the second week. Bcl-2 expression, undetectable in undifferentiated cells, increased progressively from the first week. From our results, we suggest that, at least in our model, Bcl-2-related proteins might be involved in neuronal differentiation.