The influence of strabismus and monocular deprivation on the size of callosal cells in cortical areas 17 and 18 of the cat

To reveal the changes in visual cortex structure following impaired early binocular experience, the size (somatic area) of callosal cells in areas 17, 18 ofmonocularly deprived and convergent strabismic cats was measured. Horseradish peroxidase was injected into the single ocular dominance columns of areas 17, 18 and the transition zone 17/18. In both groups of impaired cats the mean size of callosal cells in area 17 was increased in comparison to intact cats. In area 18, the similar difference was found in monocularly deprived cats only. It was shown that the differences in the mean sizes of cells are due to the increase of the number of large cells. In strabismic cats, the portion of large cells (soma > 200 mkm2) in area 17 was 58% and in area 18 was 8%. The relative share of large cells in areas 17 and 18 of monocularly deprived cats was similar (28 and 26 % correspondingly). These data show that early binocular vision impairments may lead to the changes in cytoarchitecture of cortical layers where the interhemispheric connections originate.     

G1 phase regulation, area-specific cell cycle control, and cytoarchitectonics in the primate cortex

We have investigated the cell cycle-related mechanisms that lead to the emergence of primate areas 17 and 18. These areas are characterized by striking differences in cytoarchitectonics and neuron number. We show in vivo that (1) area 17 precursors of supragranular neurons exhibit a shorter cell cycle duration, a reduced G1 phase, and a higher rate of cell cycle reentry than area 18 precursors; (2) area 17 and area 18 precursors show contrasting and specific levels of expression of cyclin E (high in area 17, low in area 18) and p27Kip1 (low in area 17, high in area 18); (3) ex vivo up- and downmodulation of cyclin E and p27Kip1 show that both regulators influence cell cycle kinetics by modifying rates of cell cycle progression and cell cycle reentry; (4) modeling the areal differences in cell cycle parameters suggests that they contribute to areal differences in numbers of precursors and neuron production.     

成纤维细胞生长因子18(FGF18)的研究进展

成纤维细胞生长因子18 (fibroblast growth factor 18,FGF18)是成纤维细胞生长因子家族( FGFs)的成员之一.研究发现,FGF 18不仅在骨骼发育和生长期对软骨形成和成骨生成起着重要的作用,其功能也已延伸至其他许多生物过程,尽管对FGF18作为一个有用治疗靶点发挥作用的功能和机制仍有待进一步的发现及研究.现针对FGF18的特点,及其在骨骼发育中的功能,特别其在未来具有潜在应用领域上的研究进展进行综述.     

Localization of aldosterone and corticosterone in the central nervous system,assessed by quantitative autoradiography

Nuclear localization of tritiated aldosterone in the CNS was studied in rats by numerical evaluation of silver grains, deposited over neuronal cell nuclei in thawmounted autoradiograms, and compared with the localization obtained after prior administration of a 100-fold excess of radioinert aldosterone, corticosterone or 18-hydroxy-11-deoxycorticosterone (18-OH-DOC). Corticosterone and 18-OH_DOC completely prevented nuclear localization in most regions examined. However, in contrast to pretreatment with aldosterone, pretreatment with corticosterone and 18-OH-DOC did not completely prevent the concentration of radio-activity in the cell nuclei of the indusium griseum. Traces of radioactivity were, furthermore, retained in areas CA₁ and CA₂ and the dentate gyrus in rats exposed to corticosterone, but not to 18-OH-DOC, prior to [³H]aldosterone. A similar profile of silver grain distribution to that noted with aldosterone was found for corticosterone except that with tritiated corticosterone the most intense concentration of radioactivity occurred in hippocampal areas CA₁ and CA₂ and not in the indusium griseum. Prior administration of excess deoxycorticosterone acetate abolished nuclear accumulation of tritiated corticosterone. Dihydrotestosterone, on the other hand, failed to compete with tritiated corticosterone at a dose 200-fold in excess of the tritiated steroid.We conclude that (1) a receptor readily shared by aldosterone, corticosterone, 18-OH-DOC and DOC, but not by dihydrotestosterone, is widely distributed throughout the CNS, (2) a receptor shared by aldosterone and 18-OH-DOC, but not by corticosterone may be present in hippocampal areas CA₁ and CA₂, (3) that both these as well as the receptor accepting dihydrotestosterone can be located within the same cell.Dedicated to K. A. C. Elliott on his 80th birthday.     

Feed-forward, feedback and lateral interactions in membrane potentials and spike trains from the visual cortex in vivo.

Neurons in the visual cortex receive input from the lateral geniculate nucleus (feed-forward), higher order visual areas (feedback) and local neurons in the surroundings (lateral interactions). Here we first briefly review the approximate timing and proportion of these three types of influences on the membrane potentials in visual areas 17, 18 and 19. Then we present original results from an independent component analysis of multiunit spike trains in the same visual areas to resolve the contribution from these three sources. We stimulated the visual cortex of the ferret with a small transient contrast square stimulus and recorded the multiunit activity in areas 17, 18 and 19 with single or multiple electrodes. The spike trains had three reproducible components having their maxima at 40, 55 and 105ms after the start of the presentation of the stimulus. The time course of the third component was significantly correlated with the population membrane potential in the supragranular layers of areas 17, 18 and 19. The first spike train component was interpreted as a feed-forward response, the second spike train component as driving the laterally spreading depolarization and the third spike train component as the firing caused by the lateral spreading- and the feedback depolarization.     

Distribution of cholesterol and galactosylceramide in rat cerebellar white matter

White matter and the inner granular layer of rat cerebellum was analysed by imaging time-of-flight secondary-ion mass spectrometry (TOF-SIMS) equipped with a Bi+ ion cluster gun. Samples were prepared by high pressure freezing, freeze-fracturing and freeze drying or by plunge freezing and cryostat sectioning. The identified and localized chemical species were: sodium, potassium, phosphocholine, cholesterol and galactosylceramide (GalC) with carbon chain lengths C18:0 (N-stearoyl-galactosylceramide) and C24:0 (N-lignoceroylgalactosylceramide) with CH24:0 (hydroxy-lignoceroylgalactosylceramide). We report new findings regarding the organization of myelin in white matter. One is cholesterol-rich, ribbon-shaped 10-20 microm areas excluding Na+ and K+. The second finding is the different distribution of GalC C18 and GalC C24 in relation to these areas, where GalC C18 was localized in cholesterol-rich areas and GalC C24 was localized in Na/K-enriched areas. The distribution of GalC was in small spots, homogeneous in size, of 0.8-1.5 microm. Sample preparation with high pressure freezing allowed separate localization of sodium and potassium in tissue samples.     

Structure of reciprocal connections in visual cortical areas 17 and 18 in cats

Single cortical columns of areas 17, 18 in the cat were microiontophoretically injected with horseradish peroxidase. Spatial and laminar distributions of retrogradell labelled cells in both areas were investigated. Following injections in area 17 or in area 18 the labelled cells' region in area 17 was elongated (in a tangential plane) along the representation of visual field horizontal meridian. However the labelled cells' region in area 18 was elongated along the representation of vertical meridian. Such projection patterns appear to be common in these cortical areas throughout the central 10 degrees on various elevations (from -40 degrees to +10 degrees) of the visual field representation. Thus the spatial arrangement of intrinsic and extrinsic connections in each area coincides, at the same time in area 17 they are orthogonal to area 18. The following visual information exchange scheme may be suggested. Area 17 may supply the area 18 with more detailed information on the horizontal component of the visual image, and in the opposite direction the information on the vertical component of the same image may be supplied.     

FISH mapping of 18S-28S and 5S ribosomal DNA, (GATA)n and (TTAGGG)n telomeric repeats in the periwinkle Melarhaphe neritoides (Prosobranchia, Gastropoda, Caenogastropoda)

Spermatocyte chromosomes of Melarhaphe neritoides (Mollusca, Prosobranchia, Caenogastropoda) were studied using fluorescent in situ hybridization (FISH) with four repetitive DNA probes (18S rDNA, 5S rDNA, (TTAGGG)n and (GATA)n). Single-colour FISH consistently mapped one chromosome pair per spread using either 18S or 5S rDNA as probes. The telomeric sequence (TTAGGG)n hybridized with termini of all chromosomes whereas the (GATA)n probe did not label any areas. Simultaneous 18S-5S rDNA and 18S-(TTAGGG)n FISH demonstrated that repeated units of the three multicopy families are closely associated on the same chromosome pair.     

Two new species of the genus Leenurina Najt & Weiner, 1992 (Collembola, Neanuridae, Caputanurininae) from Primorskij Kraj (Russia)

Leenurina khualazasp. n. and Leenurina pomorskiisp. n., two new species from East Russia (Primorskij Kraj) are described. They are closely related to Leenurina jasii Najt & Weiner, 1992 from North Korea, from which they differ mainly in the number of tibiotarsal chaetae (19, 19, 18 in the new species versus 18, 18, 17 in Leenurina jasii), several chaetotaxic features and organization of dorsal granulation. The two new species may be separated by tertiary granulation (large areas fringed with large secondary granules in Leenurina pomorskii, small rounded or hexagonal areas with smaller secondary granules in Leenurina khualaza), coloration (light blue in Leenurina khualaza versus white in Leenurina pomorskii) and number of eyes (2+2 eyes in Leenurina khualaza versus 3+3 eyes in Leenurina pomorskii). An updated diagnosis of the genus Leenurina Najt & Weiner, 1992 and a key to species of Caputanurininae are given.     

Biological quality of running waters in protected areas: the influence of size and land use

There are still substantial questions about whether protected areas affect the quality and biodiversity of surface waters within their borders. In this study, the size and land use of 19 protected areas of Latium Region (central Italy) were related to the biological quality of 32 streams running inside them. Additionally, the biological quality of 18 out of the 32 streams was compared with the quality recorded on the same streams outside the boundaries of the protected areas. The biological quality was assessed using the Extended Biotic Index, which indicates the macroinvertebrate community health. The quality of 32 study streams running through the protected areas was not related to the size of these areas, but it did reflect land use. On average, the 18 study sites inside protected areas had biological quality similar to external control sites. In the protected areas, the biological quality of streams was higher than for the same streams in the surrounding territory provided that anthropogenic changes were fewer. These data indicate that the creation of protected areas per se does not increase freshwater biodiversity and that land use has a major impact on the biological quality of the stream in a protected area. As a consequence, a higher number of reserves or landscape designations specifically created for aquatic conservation is necessary and recovery programs aimed at restoring physical habitats and reducing sources of impact to aquatic life have to be pursued. Also, where the anthropogenic impact is high (e.g., as in the case of strongly urbanised areas), the creation of effective protected areas might improve the biological quality of water courses.     

Correlation of the cell phenotype of cultured cell lines with their adhesion to components of the extracellular matrix

The differential adhesion of cultured mammalian clonal cell lines to components of the extracellular matrix was examined by kinetic adhesion and long-term growth assays. Uniform artificial matrices were prepared by air drying collagen Type I solution (C) onto a microtiter well and then air drying a solution containing a single glycosaminoglycan (GAG): hyaluronic acid (HA), chondroitin sulfate-4 (CHS-4), or chondroitin sulfate-6 (CHS-6). The adhesion of [3H]thymidine-prelabeled cells suspended in fibronectin (FN) depleted medium was measured at 2 and 6 hr. Neuroblastoma (N18, Lan 1) and melanoma (B16, G361, S91) cell lines exhibited a significantly greater percentage of cells adhering to one or more C-GAG matrices compared with C matrices. Maximal adhesion at 2 hr was to C-HA. In contrast at 2 hr, two glial, two epithelial, and one fibroblastic cell line showed unchanged or significantly decreased binding to C-GAG compared with C matrices. Further experiments using a neuroblastoma (N18) and a glioma (C6) cell line indicated that the adhesion patterns were not altered either by the method of dissociation from the tissue culture dish, preincubation with exogenous GAG, or the addition of exogenous fibronectin. Assays of N18 and C6 adhesion to matrices made from a non-GAG polyanionic compound, polygalacturonic acid (PGA), did not yield the same adhesion patterns as C-HA matrices. Long-term growth studies of a neuroblastoma (N18) melanoma (S91), and glioma (C6) cell line on nonuniform matrices deliberately prepared with GAG-rich and GAG-poor regions complemented the observations from the kinetic adhesion assays. N18 and S91 cells did not grow on areas which did not contain GAG by toluidine blue staining. However, the C6 cells did not grow on areas which did strongly stain for GAG. A quantitative analysis of the long term growth of N18 and C6 cells substantiated these observations. All these data indicate that the cellular phenotype may be correlated with matrix adhesion. Neuroblastomas and melanomas have a greater affinity for GAG-containing matrices while glial, epithelial, and fibroblastic cells appear to have a greater or equal affinity for collagen matrices.     

衰老性记忆障碍与脑突触体内游离[Ca^2＋]i的相关性

采用行为观察和生化检测相结合的方法,在过去工作的基础上,研究了１２月龄和１８月龄小鼠学习记忆能力的变化和１８月龄小鼠四个脑区（海马、大脑皮层、四叠体和小脑）交触体内「Ｃａ＾２＋」ｉ的水平,同时还比较了老年记忆保持良好组与记忆障碍组小鼠的脑钙水平。结果表明,随着年龄的增长,小鼠的学习记忆能力显著下降,上述脑区（除大脑皮层外）突触内「Ｃａ＾２＋」ｉ均明显升高,其中老年记忆障碍小鼠脑钙水平升高最为显著。     

The postnatal developmental localization of pro-opiomelanocortin and alpha melanocyte stimulating hormone in the medio-basal hypothalamus of the rat

This immunocytochemical study of the late postnatal development of the medio-basal hypothalamus revealed the presence of ACTH 1-39 like positivity in neurons of the arcuate nucleus form the begin of this study (day E 18-20) onwards. Alpha MSH positivity, on the contrary, is not present in cells of the same area before day P 16. No other areas in the developing medio-basal hypothalamus contain perikaryal positivity for alpha M-SH or ACTH 1-39. The pituitary contains ACTH 1-39 like positivity from the begin of this study (day E 18-20) onwards. Fibers are positive for alpha MSH during the fetal development of the medio-basal hypothalamus, demonstrating an overal reactivity without varicosities and restricted to bundles or neuropil areas. Towards P 16 the alpha MSH positivity diminishes in the whole medio-basal hypothalamus, remaining present only in large fibre systems like the fornix. ACTH 1-39 like fiber positivity is already distributed in arcuate and periventricular regions at days E 20-PO, reaching its mature extension at day P2. After P16 alpha MSH positive threads, possessing varicosities are restricted to the same areas as ACTH 1-39 like fiber positivity is.     

Characterization of the nicotinic ligand 2-[18F]fluoro-3-[2(S)-2-azetidinylmethoxy]pyridine in vivo

The biodistribution of the nicotinic acetylcholine receptor (nAChR) radioligand 2-[18F]fluoro-3-[2(S)-2-azetidinylmethoxy]pyridine ([18F]fluoro-A-85380, half-life of fluorine-18 = 110 min) in selected rat brain areas was assessed in vivo. The radiotracer showed a good penetration in the brain. The regional distribution of the radioligand was consistent with the density of nAChRs determined from previous studies in vitro. Sixty minutes post-injection, the highest uptake was observed in the thalamus, (1% I.D./g tissue), an intermediate one in the frontal cortex (0.78% I.D./g tissue), and the lowest in the cerebellum (0.5% I.D./g tissue). Pretreatment with several nAChR ligands (nicotine, cytisine, epibatidine, unlabeled fluoro-A-85380) substantially reduced uptake of the radioligand in the three cerebral areas. Pretreatment with the nAChR channel blocker mecamylamine or with the muscarinic receptor antagonist dexetimide had no appreciable effect on the uptake of fluoro-A-85380. These results support the high in vivo selectivity and specificity of fluoro-A-85380. Therefore, [18F]fluoro-A-85380 may be useful for positron emission tomography study of nAChRs in humans.     

Taxonomy and cytology of the genus Albuca (Hyacinthaceae) in East Africa

The following taxa are represented in East Africa (Kenya, Tanzania, Uganda): Albuca kirkii (Bak.) Brenan (2n = 18), A. abyssinica Murr. (2n = 18, 36), A. tenuis Knudtzon sp. nov. (2n = 18). The general haploid karyotype is 3L + 6S. The two first species are fairly heterogenous, with characteristic facies in local populations, but with little or no constant correlation of characters over wide areas. Infraspecific incompatibility is observed, but only slightly combined with differences in morphology or level of ploidy.     

计算任务男女性别差异的fMRI研究

目的:用功能磁共振(functional Magnetic Resonance Imaging,FMRI)探讨男女不同性别在计算任务时脑活动的差异。方法:对10例男性、8例女性正常年青受试者进行简单及复杂任务的功能MRI扫描,采用SPM2软件进行数据分析和脑功能区定位。结果:计算任务中男女主要激活区域均为额前区、顶叶、枕叶及小脑,男性额前区及顶叶等计算功能区激活范围较女性广,其中以复杂计算为著。结论:相同的计算任务,男性激活的脑功能区范围多于女性。     

Effect of endogenous serotonin on the binding of the 5-hT1A PET ligand 18F-MPPF in the rat hippocampus: kinetic beta measurements combined with microdialysis

By using a combination of an original beta+-sensitive intracerebral probe and microdialysis, the effect of increased endogenous serotonin on specific binding of 18F-MPPF [4-(2'-methoxyphenyl)-1-[2'-[N-(2"-pyridinyl)-p-fluorobenzamido]ethyl]piperazine] to the serotonin-1A (5-HT1A) receptors was investigated in the hippocampus of the anaesthetized rat. Our beta-sensitive probe prototype was sensitive enough to obtain specific 18F-MPPF time-activity curves in the rodent (hippocampus/cerebellum ratio approximately 2). The serotonin neuronal release was pharmacologically enhanced using fenfluramine at three different doses (1, 2 and 10 mg/kg intravenous) multiplying by 2-15 the extracellular serotonin in the hippocampus. These extracellular variations of extracellular serotonin resulted in dose-ranging decreases in 18F-MPPF-specific binding in the same rat. Our results showed for the first time that 18F-MPPF binding could be modulated by modifications of extracellular serotonin in the rat hippocampus. These results were confirmed by the enhancement of extracellular radioactivity collected in dialysates after the displacement of 18F-MPPF by fenfluramine. After modelization, 18F-MPPF binding could constitute an interesting radiotracer for positron emission tomography in evaluating the serotonin endogenous levels in limbic areas of the human brain.     

第一和第二语言Stroop任务中EEG同步化分析

采用基于多元自回归的瞬时EEG相干方法研究了十位汉英双语者执行Stroop任务时脑神经电活动及其功能皮层区的协同作用。结果显示：在β1(13-18Hz)频段,无论是汉语(第一语言,L1)还是英语(第二语言,L2)呈现的刺激,不一致条件的EEG相干值明显大于一致条件的EEG相干值,表明β1频段对刺激类型敏感;与L2相比,L1的Stroop任务中,额一顶区的相干值显著增强。EEG相干值反映了不同脑皮层间的相互作用强度。因此研究结果表明：判断和处理冲突信息(如Stroop的不一致条件)时脑功能皮层区之间的协同作用增强;相对于第二语言,第一语言处理过程中额一顶区之间的通信协作增加。     

A comparison of the take of embryonic amygdala and visual cortex transplants in the rat brain in connection with the possible compensation of functional disorders]

Transplantation of embryonic (E17-18) visual cortex and amygdala was performed into corresponding damaged areas of the adult rat brain. It was shown in Nissl and Golgi preparations (by comparing qualitative and quantitative findings) that 2-6 months after operation the grafts were successful in case of putting them into the corresponding brain areas (cortex to cortex, or amygdala to amygdala). Graft's integration resulted in a selective increase of dendrite length and ramification towards the area of graft-host interface both in amygdala and visual cortex grafts. In case of inadequate graft-host integration the stratification of the grafted visual cortex could be observed. The structural reorganization of grafted neurones is compared with physiological and behavioural findings during the recovery processes in damaged brain.