Distal CA1 Maintains a More Coherent Spatial Representation than Proximal CA1 When Local and Global Cues Conflict

Entorhinal cortical projections show segregation along the transverse axis of CA1, with the medial entorhinal cortex (MEC) sending denser projections to proximal CA1 (pCA1) and the lateral entorhinal cortex (LEC) sending denser projections to distal CA1 (dCA1). Previous studies have reported functional segregation along the transverse axis of CA1 correlated with the functional differences in MEC and LEC. pCA1 shows higher spatial selectivity than dCA1 in these studies. We employ a double rotation protocol, which creates an explicit conflict between the local and the global cues, to understand the differential contributions of these reference frames to the spatial code in pCA1 and dCA1 in male Long–Evans rats. We show that pCA1 and dCA1 respond differently to this local-global cue conflict. pCA1 representation splits as predicted from the strong conflicting inputs it receives from MEC and dCA3. In contrast, dCA1 rotates more in concert with the global cues. In addition, pCA1 and dCA1 display comparable levels of spatial selectivity in this study. This finding differs from the previous studies, perhaps because of richer sensory information available in our behavior arena. Together, these observations indicate that the functional segregation along proximodistal axis of CA1 is not of the amount of spatial selectivity but that of the nature of the different inputs used to create and anchor spatial representations.SIGNIFICANCE STATEMENT Subregions of the hippocampus are thought to play different roles in spatial navigation and episodic memory. It was previously thought that the distal part of area CA1 of the hippocampus carries lesser information about space than proximal CA1 (pCA1). We report that distal CA1 (dCA1) spatial representation moves more in concert with the global cues than pCA1 when the local and the global cues conflict. We also show that spatial selectivity is comparable along the proximodistal axis in this experimental protocol. Thus, different parts of the brain receiving differential outputs from pCA1 and dCA1 receive spatial information in different spatial reference frames encoded using different sets of inputs, rather than different amounts of spatial information as thought earlier.     

A copper deficient diet prevents hepatic copper accumulation and dysfunction in Long-Evans Cinnamon (LEC) rats with an abnormal copper metabolism and hereditary hepatitis

 Long-Evans Cinnamon (LEC) rats that develop spontaneous hepatitis due to an inherently abnormal Cu metabolism have recently been established. This investigation concerns the effects of a Cu-deficient diet on the Cu metabolism linked to hepatic injury in LEC rats. The hepatic Cu concentration at 30 days after birth was 94±4 Cu μg/g liver in LEC rats, whereas that of Fischer rats at the same age was 7±1 Cu μg/g. From 30 days after birth, all rats were fed a semisynthetic diet with two different levels of Cu, 0.5 or 30 μg/g food, for 35 days. In LEC rats fed a Cu-deficient diet (0.5 μg/g), the hepatic Cu concentration was 39±7 μg/g. The Cu-normal diet (30 μg/g) LEC group had a concentration of 357±15 μg/g in the hepatic Cu. The group had significantly higher aspartate aminotransferase (ASAT), alanine aminotransferase (ALAT) and γ-glutamyl transferase (GGT) levels than did the LEC rats given the Cu-deficient diet. These results suggest that the occurrence of acute hepatitis in LEC rats can be prevented by feeding the animals a Cu-deficient diet. Received: 18 October 1993 / Accepted: 11 July 1994     

A critical review of the data related to the safety of quercetin and lack of evidence of in vivo toxicity, including lack of genotoxic/carcinogenic properties.

Quercetin is a naturally-occurring flavonol (a member of the flavonoid family of compounds) that has a long history of consumption as part of the normal human diet. Because a number of biological properties of quercetin may be beneficial to human health, interest in the addition of this flavonol to various traditional food products has been increasing. Prior to the use of quercetin in food applications that would increase intake beyond that from naturally-occurring levels of the flavonol in the typical Western diet, its safety needs to be established or confirmed. This review provides a critical examination of the scientific literature associated with the safety of quercetin. Results of numerous genotoxicity and mutagenicity, short- and long-term animal, and human studies are reviewed in the context of quercetin exposure in vivo. To reconcile results of in vitro studies, which consistently demonstrated quercetin-related mutagenicity to the absence of carcinogenicity in vivo, the mechanisms that lead to the apparent in vitro mutagenicity, and those that ensure absence of quercetin toxicity in vivo are discussed. The weight of the available evidence supports the safety of quercetin for addition to food.     

Metal contents of liver parenchyma after percutaneous ethanol injection or radiofrequency ablation in patients with hepatocellular carcinoma before and after trientine hydrochloride therapy

We administered trientine hydrochloride, a drug used in the treatment of Wilson's disease, to patients with hepatocellular carcinoma after radical treatment with percutaneous ethanol injection or radiofrequency ablation, and examined its effect on the reduction of liver-tissue copper content. We enrolled 24 patients with 3 or fewer primary lesions of Child class A or B hepatocellular carcinoma with diameters of 3 cm or less who had undergone radical treatment with percutaneous ethanol injection or radiofrequency ablation. Trientine hydrochloride was orally administered in a single daily dose of 250 mg to 12 patients before a meal (at fasting, group 1) or at a total daily dosage of 750 mg, divided into 3 doses, to 12 patients (group 2). This study was a randomized between-groups comparative study of 12 weeks' duration. We used the particle-induced x-ray-emission method to determine liver-tissue mineral content. Urine copper and serum mineral levels were also measured, and transaminase levels were examined. Liver-tissue copper content decreased significantly, to 160.1 microg/g dry weight, after treatment, compared with the pretreatment level of 306.8 microg/g dry weight (P <.05). We detected no significant difference in iron or zinc content before and after treatment. The copper content was significantly reduced after treatment in both groups (P <.05). The urine copper level was significantly increased after 1 week of treatment but decreased thereafter. Serum copper levels were significantly reduced after treatment (P <.01). We detected no significant difference in transaminase level before and after treatment. Iron-deficiency anemia in 1 patient after 12 weeks' treatment was the only adverse reaction, and it was improved by the administration of an iron product. We noted no other overt adverse reactions. In patients with hepatocellular carcinoma, trientine hydrochloride therapy may significantly reduce copper content in liver tissue.     

Brain-derived neurotrophic factor plasma levels in patients suffering from post-traumatic stress disorder

In both animals and humans, stress has been demonstrated to reduce the expression of the Brain-Derived Neurotrophic Factor (BDNF), a neurotrophin (NT) which promotes the proliferation, survival and differentiation of neurons. Although traumatic events have been found to be associated with lower BDNF plasma levels in affective disorders, no study has explored this parameter in patients with post-traumatic stress disorder (PTSD). We, therefore, measured BDNF plasma level in 18 patients with PTSD and in 18 healthy control subjects. Diagnoses were assessed by the Structured Clinical Interview for DSM-IV, while the specific symptoms were examined in the patients by means of the Impact of Event Scale for PTSD and the traumas experienced were assessed by using the Life Events Checklist. BDNF plasma levels were evaluated by means of a standardized Elisa method. The results, while showing significantly lower BDNF levels in PTSD patients, as compared with those of healthy subjects (p = 0.001), although obtained in a small sample size, would suggest that this NT may be involved in the pathophysiology of PTSD.     

淋巴管内皮细胞与PGA的相容性研究

目的研究人淋巴管内皮细胞(Lymphatic endothelial cells,LEC)与可吸收生物材料聚羟基乙酸(Polyglycolic acids,PGA)的相容性,为组织工程化淋巴管的构建奠定基础。方法采用免疫磁珠分离法,从幼儿包皮组织中分离出LEC,扩增至第3代,与PGA混合培养,形成细胞-生物材料复合物。每两天换液1次,观察细胞形态和黏附生长状况。体外培养1周后,行电镜观察和RT-PCR检测。结果复合物体外培养1周后,LEC黏附在PGA支架上,细胞分泌大量基质。RT-PCR提示Podoplanin、LYVE-1、VEGFR-3和Prox-1均呈阳性表达,LEC表型未发生改变。结论 LEC与PGA有良好的细胞相容性,PGA可作为组织工程化淋巴管构建的支架材料。     

系统性红斑狼疮(SLE)检验方法的分析比较

目的探索系统性红斑狼疮的敏感特异实验室诊断手段。方法系统性红斑狼疮(SLEA)检测方法:采用LEC法、免疫学方法(ds-DNA,ANA),对245例患者进行对比分析。结果96例系统性红斑狼疮疾病患者阳性检出率分别为LEC法72.9%,ds-DNA法96.8%,ANA法88.5%,245例其它免疫疾病患者阳性检验率分别为:LEC法9.4%,ds-DNA法0.8%,ANA法86.1%。结论LEC法阳性检出率低,特异性差,ANA法阳性检出率较高,特异性很差,最佳检测方法为ds-DNA法。