The Basomedial and Basolateral Amygdaloid Nuclei Contribute to the Induction of Long-term Potentiation in the Dentate Gyrus In Vivo

Recent behavioural studies have provided evidence that the amygdala modulates hippocampal-dependent memory. To test the possibility that the amygdala modulates hippocampal synaptic plasticity, we investigated the effects of surgical lesions of the amygdaloid nuclei on the induction of long-term potentiation (LTP) in the dentate gyrus of anaesthetized rats. Previously we reported that LTP in the dentate gyrus was attenuated by lesion of the basolateral amygdala, but was not affected by lesion of the central amygdala. In the present study, dentate gyrus LTP was significantly attenuated by basomedial amygdala lesion but not by medial amygdala lesion. These results suggest that, among the amygdaloid nuclei, the basomedial and basolateral nuclei are involved in the modulation of hippocampal plasticity. The roles of the basomedial and basolateral amygdala were further supported by experiments examining the effects of electrical stimulation of these nuclei. High-frequency stimulation of the basomedial amygdala alone did not induce dentate gyrus LTP, but when applied at the same time as tetanic stimulation of the perforant path increased the magnitude of the dentate gyrus LTP. Similarly, high-frequency stimulation of the basolateral amygdala enhanced LTP induced by tetanic stimulation of the perforant path. Furthermore, facilitation of dentate gyrus LTP by basomedial or basolateral amygdala stimulation was observed even in rats lesioned in either amygdala, suggesting that neurons in the basomedial and basolateral amygdala can modulate dentate gyrus LTP independently. Activity-dependent facilitation of hippocampal plasticity by the basomedial and basolateral amygdala may underlie memory processing associated with emotion.     

Variation in serum binding of tertatolol mediated by disease-induced modification of alpha-acid glycoprotein concentration

Summary The serum concentrations of ₁-acid glycoprotein (AAG), albumin (HSA) and non-esterified fatty acids, and the serum binding of tertatolol were measured in four groups of individuals: healthy control subjects (n=24), and patients with inflammation (n=28), and hepatic (n=20) and renal (n=27) insufficiency.Serum binding of tertatolol was increased in patients with inflammation (94.6%), decreased in patients with hepatic insufficiency (88.8%) and it was unchanged in patients with renal insufficiency (92.8%) as compared to controls (92.7%).Multivariate analysis indicated that the changes were mainly related to concomitant changes in AAG concentration, which could account for 57% of intersubject variability in the bound/free ratio, and to a lesser extent in HSA, which accounted for only 4% of the variability in the binding.The data show that the free fraction of the basic drug tertatolol in serum is affected by pathological conditions that cause changes in AAG concentration.     

Human testicular protein TPX1/CRISP-2: localization in spermatozoa, fate after capacitation and relevance for gamete interaction

Testicular protein Tpx-1, also known as CRISP-2, is a cysteine-rich secretory protein specifically expressed in the male reproductive tract. Since the information available on the human protein is limited to the identification and expression of its gene, in this work we have studied the presence and localization of human Tpx-1 (TPX1) in sperm, its fate after capacitation and acrosome reaction (AR), and its possible involvement in gamete interaction. Indirect immunofluorescence studies revealed the absence of significant staining in live or fixed non-permeabilized sperm, in contrast to a clear labelling in the acrosomal region of permeabilized sperm. These results, together with complementary evidence from protein extraction procedures strongly support that TPX1 would be mainly an intra-acrosomal protein in fresh sperm. After in vitro capacitation and ionophore-induced AR, TPX1 remained associated with the equatorial segment of the acrosome. The lack of differences in the electrophoretic mobility of TPX1 before and after capacitation and AR indicates that the protein would not undergo proteolytical modifications during these processes. The possible involvement of TPX1 in gamete interaction was evaluated by the hamster oocyte penetration test. The presence of anti-TPX1 during gamete co-incubation produced a significant and dose-dependent inhibition in the percentage of penetrated zona-free hamster oocytes without affecting sperm motility, the AR or sperm binding to the oolema. Together, these results indicate that human TPX1 would be a component of the sperm acrosome that remains associated with sperm after capacitation and AR, and is relevant for sperm-oocyte interaction.     

Antigen-independent cross-talk between macrophages and CD8+ T cells facilitates their cooperation during target destruction

Inflammatory sites associated with tissue destruction often contain a complex mixture of cells including macrophages as well as CD8+ and CD4+ T cells. Here, we have investigated, using islets of Langerhans as targets, if CD8+ T cells and macrophages can cooperate in tissue destruction. CD8+ T cells obtained from the islet inflammatory lesion of non-obese diabetic mice or cloned islet-specific CD8+ T cells were ineffective in destroying islets on their own. Including increasing numbers of macrophages in co-cultures of islets and islet-derived or cloned CD8+ T cells progressively increased and accelerated islet destruction. Macrophages alone were ineffective. Macrophage-depleted islets were not destroyed by islet-derived CD8+ T cells. For cooperative islet destruction to occur, beta cells, but not macrophages, needed to be able to present antigens to CD8+ T cells. CD8+ T cells triggered NO production by macrophages, while macrophages triggered IFN-gamma production by CD8+ T cells. Each of these factors was partially effective, but not sufficient, for maximal islet destruction. Antibodies specific for ICAM-1 and LFA-1 inhibited both cooperative islet destruction and cross-stimulation of CD8+ T cells and macrophages. The data suggest that if CD8+ T cells become only weakly activated by target cells, they are not able to destroy target tissue on their own. However, such CD8+ T cells and local macrophages may still cross-stimulate each other, which then facilitates target destruction. For this to occur, target cells, but not macrophages, need to present antigen to CD8+ T cells.     

Neck proprioception compensates for age-related deterioration of vestibular self-motion perception

Vestibular functions are known to show some deterioration with age. Vestibular deterioration is often thought to be compensated for by an increase in neck proprioceptive gain. We studied this presumed compensatory mechanism by measuring psychophysical responses to vestibular (horizontal canal), neck and combined stimuli in 50 healthy human subjects as a function of age (range 15–76 years). After passive horizontal rotations of head and/or trunk (torso) in complete darkness (dominant frequencies 0.05, 0.1, and 0.4 Hz), subjects readjusted a visual target to its remembered prerotational location in space. (1) Vestibular-only stimulus (whole-body rotation); subjects' responses were shifted towards postrotatory body position, this only slightly at 0.4 Hz and pronounced at 0.1 and 0.05 Hz. These errors reflect the known physiological drop of vestibular gain at low rotational frequency. They exhibited a slight but significant increase with age. (2) Neck-only stimulus (trunk rotated, head stationary); the responses showed errors similar to those upon vestibular stimulation (with offset towards postrotatory trunk position) and this again slightly more with increasing age. (3) Vestibular-neck stimulus combination during head rotation on stationary trunk; the errors were close to zero, independent of stimulus frequency and the subjects' age. (4) Opposite stimulus combination (trunk rotated in the same direction as the head, but with double amplitude); the errors were clearly enhanced, essentially reflecting the sum of those with vestibular-only and neck-only stimulation. Taken together, we find a parallel increase in neck- and vestibular-related errors with age, in seeming contrast to previous studies. We explain our and the previous findings by a vestibular-neck interaction model in which two different neck signals are involved. One neck signal is used, in combination with the vestibular signal, for estimating trunk-in-space rotation. It is internally shaped to always match the vestibular signal, so that these two signals cancel each other out when summed during head rotation on stationary trunk. Because of this matching, perceived trunk stationariness during head rotation on the stationary trunk is independent of vestibular deterioration (related to stimulus frequency, age, ototoxic medication, etc.). The other neck proprioceptive signal, coding head-on-trunk rotation, is superimposed on the estimate of trunk-in-space rotation, thereby yielding a notion of head-in-space. This neck signal remains essentially unchanged with vestibular deterioration. Generally, we hold that the transformation of the vestibular signal from the head down to the trunk proceeds further to include the hip and the legs as well as the haptically perceived body support surface; by this, subjects yield a notion of support kinematics in space. As a consequence, spatial orientation is impaired by chronic vestibular deterioration only to the extent that the body support is moving in space, while it is unimpaired (determined by proprioception alone) during body motion with respect to a stationary support. Electronic Publication     

FGF signaling segregates biliary cell-lineage from chick hepatoblasts cooperatively with BMP4 and ECM components in vitro.

Intrahepatic bile ducts (IHBDs) are indispensable for transporting bile secreted from hepatocytes to the hepatic duct. The biliary epithelial cells (BECs) of the IHBD arise from bipotent hepatoblasts around the portal vein, suggesting the portal mesenchyme is essential for their development. However, except for Notch or Activin/TGF-beta signaling molecules, it is not known which molecules regulate IHBD development. Here, we found that FGF receptors and BMP4 are specifically expressed in the developing IHBD and the hepatic mesenchyme, respectively. Using a mesenchyme-free culture of liver bud, we showed that bFGF and FGF7 induce the hepatoblasts to differentiate into BECs, and that BMP4 enhances bFGF-induced BEC differentiation. The extracellular matrix (ECM) components in the hepatic mesenchyme induced BEC differentiation. Forced expression of a constitutively active form of the FGF receptor partially induced BEC differentiation markers in vivo. These data strongly suggest that bFGF and FGF7 promote BEC differentiation cooperatively with BMP4 and ECMs in vivo.     

The initial vestibulo-ocular reflex and its visual enhancement and cancellation in humans

The gain (ratio of eye velocity to head velocity) of the initial horizontal vestibulo-ocular reflex (VOR) was calculated in 12 normal subjects over 350 ms during impulsive, unpredictable whole body rotation under three conditions: (1) darkness; (2) visual enhancement of the VOR, while the subjects fixated a stationary target; and (3) visual cancellation of the reflex, while subjects fixated a target that rotated with the head. The gain of the initial 80 ms of compensatory eye movement increased significantly during visual fixation in 5 subjects and decreased during attempted VOR cancellation in 3 subjects, when compared with VOR gain in darkness. Compensatory vestibular smooth eye movements were slowed, becoming curved at the onset of VOR cancellation, at mean latencies ranging from 78 to 149 ms in individual subjects (group mean 128 ms). At about 190 ms, quick phases moved the eyes in the same direction as head and target motion. The subsequent vestibular eye movements were about 50% slower than the initial smooth eye movements, indicating more effective cancellation. Visual enhancement of the VOR can occur prior to the onset of pursuit, providing evidence that fixation and smooth pursuit are distinct ocular motor systems. Visual cancellation of the VOR also begins prior to smooth pursuit initiation and becomes more effective after the latency of smooth pursuit.     

预测蛋白质相互作用位点的计算方法研究(一)

许多重要的细胞过程如信号转导、转运、细胞运动以及多数调节机制均由蛋白-蛋白之间的相可作用介导，蛋白质之间的相互作用在物理上是通过在两个相互作用蛋白之间形成接触面的短残基序列来实现。识别蛋白-蛋白相互作用位点，以及检测相互作用氨基酸残基之间的特异性与强度特异性，是一个具有重要应用前景的课题，它的应用范围从理性的药物设计到代谢和信号转导网络的分析。虽然有不少准确度不断提高的实验技术和计算方法来检测蛋白质之间的相互作用，但很少有方法能够精确地指出参与蛋白质相互作用的特定残基及其位置，而这些信息是将相互作用数据直接应用于药物开发所必需的。随着生物信息学和计算生物学的发展，通过研究已知蛋白-蛋白相互作用位点的这些不同特征．出现了一些利用序列与结构信息顶测蛋白-蛋白相互作用位点的计算方法。本文简要介绍了近年来在顶测蛋白-蛋白的相互作用位点方面取得一定进展的计算方法，包括基于基因组信息的计算方法、基于蛋白质初级序列的计算方法以及基于蛋白复合物结构信息的计算方法。虽然这些方法在过去儿年里取得了显著的进展，但是大多数在这方面的研究仍处于起步阶段．而现在数据库的不足和实验技术的缺陷对计算预测方法的进一步发展和公平性评价也存在着较大的影响，要提高蛋白-蛋白相巨作用位点预测的鲁棒性与可靠性，仍要有很多的工作要做。（发表在这里的是第一部分）     

Murine interleukin 5 receptor isolated by immunoaffinity chromatography: comparison of determined N-terminal sequence and deduced primary sequence from cDNA and implication of a role of the intracytoplasmic domain

The murine interleukin 5 receptor (IL-5R) was identified by utilizing an immobilized IL-5 and an immobilized monoclonal antibody against the murein IL-5R (designated H7 mAb). The H7 mAb immunoaffinity-purified materials from the extract of cell-surface radioiodinated T88-M cells (an IL-5-dependent early B cell line) using 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS) were reacted with an immobilized IL-5 matrix. SDS-PAGE of the adsorbed fraction revealed a single band at approximately 60 kDa. The binding of the 60 kDa protein to the immobilized IL-5 matrix was inhibited by the excess IL-5. The CHAPS-extract depleted of the 60 kDa protein by the absorption with H7 mAb did not contain any IL-5 binding proteins. Immunoaffinity procedure provided a final 7400-fold purification, based on an estimation of the content of the 60 kDa protein (approximate purity: 20%) from the silver-stained pattern of SDS-PAGE. Actin was copurified with the 60 kDa protein at an approximate ratio of 1:1, suggesting that the intracytoplasmic domain of the IL-5R may interact with actin. Furthermore, soluble IL-5R (molecular mass: 50 kDa) was purified by the H7 mAb-immunoaffinity chromatography. The purified soluble IL-5R was capable of inhibiting the binding of IL-5 to T88-M cells. Preparative SDS-PAGE followed by electroblotting onto a membrane permitted the determination of the N-terminal sequence of the IL-5R. The determined N-terminal sequence of the IL-5R and the deduced primary sequence from recently isolated cDNA were compared.