The participation of the serotoninergic system in regulating the activity of the central glutamatergic/aspartatergic and GABA-ergic synapses

Selective lesion of the serotoninergic system diminished the synaptic uptake of 3H-L-glutamic acid and 3H-DL-aspartic acid, as well as the Na+(-dependent) binding of 3H-L-glutamic acid in the cortex and the brain stem. The data obtained suggest an ability of the serotoninergic system to modify presynaptic processes in amino-acidergic neurons of the CNS.     

万能轧机机组速度张力控制系统

本文介绍了速度及张力控制系统在鞍山市轧钢厂万能轧机轧制线上的应用。该系统成功地运用于型钢的双机架可逆连轧，很好地解决了可逆连轧中的速度控制问题。     

Constituents as acquisitional units of an unknown language.

3 groups of 8 English monolingual undergraduates each listened to 18 repetitions of a story into which Korean segments were gradually substituted for corresponding English segments. The segments substituted into the story were (a) words, (b) constituents, and (c) sentences. The acquisition of Korean language was tested using 10 Korean sentences presented in the story and 10 unfamiliar Korean sentences. All 3 groups responded above chance level to the familiar sentences. Only the constituent group responded above chance level to the unfamiliar sentences. It is concluded that presentation of a new language by constituents helped the learner deal with novel sentences in the new language better than presentation by words or by sentences. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The development of gesture and speech as an integrated system

Children, even at the one-word stage of language development, spontaneously produce gestures along with their speech, just as adults do. Although there appears to be a brief period prior to the onset of two-word speech during which gesture and speech do not form a well-integrated system, the ability to coordinate gesture and speech to convey a single message--and to "read" others' gestures with their speech to comprehend a message--develops early and is maintained throughout life. Gesture-speech combinations deliver a coherent message to the listener despite the fact that they consist of two different modalities of expression. According to McNeill (1992; Chapter One), this coherence is possible because gesture and speech share a common cognitive representation; that is, before the communication unfolds, gesture and speech are part of a single idea. As expression proceeds the message is parsed, with most information channeled into speech but some information channeled into gesture. Speech conveys information in a segmented, combinatorial format, whereas gesture conveys information in a global, mimetic format (see Goldin-Meadow, McNeill, and Singleton, 1996). Thus gesture and speech need not, and in fact often do not, convey the same information within a single utterance. Because gesture and speech form a unified system, mismatches between them can be a source of insight into the cognitive state of the speaker. And, indeed, it turns out that in both the young, one-word speaker and the older child (and possibly adults as well; Perry and Elder, 1996), a difference--or mismatch--between the information conveyed in gesture and the information conveyed in speech can signal readiness for cognitive growth. Whether the actual production of gesture-speech mismatches contributes to cognitive growth is an open question. That is, does the act of expressing two different pieces of information across modalities but within a single communicative act improve a child's ability to transpose that knowledge to a new level and thus express those pieces of information within a single modality? More work is needed to investigate whether the act of producing gesture-speech mismatches itself facilitates transition. Even if it turns out that the production of gesture-speech mismatches has little role to play in facilitating cognitive change, mismatch remains a reliable marker of the speaker's potential for cognitive growth. As such, an understanding of the relationship between gesture and speech may prove useful in clinical settings. For example, there is some evidence that children with delayed onset of two-word speech fall naturally into two groups: children who eventually achieve two-word speech, albeit later than the norm (that is, late bloomers), and children who continue to have serious difficulties with spoken language and may never be able to combine words into a single string (Feldman, Holland, Kemp, and Janosky, 1992; Thal, Tobias, and Morrison, 1991). Observation of combinations in which gesture and speech convey different information may prove a useful clinical tool for distinguishing, at a relatively young age, children who will be late bloomers from those who will have great difficulty mastering spoken language without intervention (see Stare, 1996, for preliminary evidence that the relationship between gesture and speech in children with unilateral brain damage correlates with early versus late onset of two-word combinations. In sum, for both speakers and listeners, gesture and speech are two aspects of a single process, with each modality contributing its own unique level of representation. Gesture conveys information in the global, imagistic form for which it is well suited, and speech conveys information in the segmented, combinatorial fashion that characterizes linguistic structures. The total representation of any message is therefore a synthesis of the analog gestural mode and the discrete speech mode. (ABSTRACT TRUNCATED)     

The present system of quantities and units for radiation protection

The International Commission on Radiation Units and Measurements has over the last decade developed operational quantities, the ambient, directional and personal dose equivalent, suitable for the measurement of radiation fields in a variety of circumstances. Experience with the use of these quantities to represent the dose limitation quantities defined by the International Commission on Radiological Protection in 1977 has been an important part of recent radiation protection metrology. The definition by International Commission on Radiological Protection in 1991 of new limitation quantities, the equivalent dose and the effective dose has necessitated a redirection of this work. The metrology field has made good progress, however. It has found that for photons, at least above 50 keV, the effective dose can be measured by the ambient dose equivalent about as well as the former effective dose equivalent. Unfortunately, for neutrons the existing and already quite severe complications have been made somewhat worse by the new quantities although not any worse in the important region between 0.1 and 1 MeV. Neutron measurements over a broad energy range are the subject of extensive evaluation and some new suggestions as the metrology field wrestles with these problems. Values of wR constitute an important part of the International Commission on Radiological Protection recommendations. A brief history of the development of higher relative biological effectiveness values for fission neutrons and alpha particles leading to the selection of 20 for wR in each case, is provided.     

Blast-furnace smelting as an example of an integrated approach to the design of gas-cleaning units

The experience that the company has gained in different sectors of industry, its huge inventory of completed projects, the excellent qualifications of its staff, the fact that it uses proven methods of calculation and observes the pertinent standards, and its collaborations with other leading Russian and foreign companies allow its specialists to not only devise sophisticated strategies for the reconstruction of existing facilities, but also to design highly efficient new gas-cleaning systems that meet customers’ requirements and satisfy international standards.     

Biological action of leptin as an angiogenic factor

Leptin is a hormone that regulates food intake, and its receptor (OB-Rb) is expressed primarily in the hypothalamus. Here, it is shown that OB-Rb is also expressed in human vasculature and in primary cultures of human endothelial cells. In vitro and in vivo assays revealed that leptin has angiogenic activity. In vivo, leptin induced neovascularization in corneas from normal rats but not in corneas from fa/fa Zucker rats, which lack functional leptin receptors. These observations indicate that the vascular endothelium is a target for leptin and suggest a physiological mechanism whereby leptin-induced angiogenesis may facilitate increased energy expenditure.     

The use of Diprivan as an anticonvulsant in the early postoperative period of an otogenic brain abscess

This is a report on a female patient with otogenic cerebellar abscess and symptomatic generalized convulsions, irresponsive to conventional diazepam and phenobarbital therapy. Fractionated propofol administration yields good effect without noteworthy changes in respiration and circulation.     

The interaction of GABA-A receptors with the serotoninergic system of the brain in regulating the testosterone level by the negative feedback mechanism

A unilateral hemicastration decreased the serotonin and 5-hydroxyindolacetic acid levels in the Wistar rat mediobasal hypothalamus, but not in the midbrain. These neurotransmitters were shown to interact in the process of androgen restoration after the hemicastration. The maximal contribution of GABAergic mechanisms in the testosterone feedback regulation involves the GABA effect via the central GABA-A receptors of the mediobasal hypothalamus' serotoninergic neurons, thus activating the hormone level restoration. The GABA seems to induce a serotonin-independent inhibition of the testosterone level stabilising after hemicastration.     

The validity of a visual searching task as an indicator of brain damage.

Required 17 brain-damaged patients, 17 non-brain-damaged psychiatric patients, and 17 nonpatient normal controls to perform a visual search. The task discriminated among the Ss at a statistically significant level. Using an optimal cut-off point, the task was 94.1% accurate in differentiating between brain-damaged and normal Ss and 79.4% accurate in differentiating between psychiatric and brain-damaged Ss. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The uptake of horseradish peroxidase by cortical synapses in rat brain. An in vivo study

Horseradish peroxidase (HRP) was introduced directly into the cerebral cortex of adult rats, which were allowed to survive for 60 min before perfusion fixation. After the tissue had been incubated to demonstrate HRP at the LM and EM levels, blocks of cortical tissue were taken at varying distances from the injection site. These eight blocks of tissue constituted a time sequence for HRP diffusion. Qualitative examination of the presynaptic terminals showed that the most commonly encountered profiles are the plain synaptic vesicles, many of which accumulate tracer. In some terminals labelled vesicles are "lined-up" in tubular fashion. Other profiles commonly labelled are coated vesicles, tubular and vacuolar cisternae, and plain and coated pinocytotic vesicles. Quantitative analyses based on the number of terminals containing labelled profiles demonstrate an early rise in the rate of labelling of both plain synaptic vesicles and coated vesicles, after which synaptic vesicle labelling rises slowly towards a plateau. By contrast, there is a late parallel increase in the rate of labelling of coated vesicles and cisternae. A more detailed analysis, based on the actual numbers of labelled and total profiles within each presynaptic terminal, highlight early and late periods of rapid labelling for plain synaptic vesicles, coated vesicles and cisternae. A further aspect of HRP incorporation studied, concerns its uptake into four delineated regions of the presynaptic terminal. Our data indicate that membrane uptake into the presynaptic terminal is accomplished mainly via coated vesicles, although plain synaptic vesicles may also be involved. Coated vesicles, in turn, appear to give rise directly to plain synaptic vesicles, with some coalescing to produce vacuolar cisternae. The latter are involved in a two-way interchange of membrane with tubular cisternae, plain synaptic vesicles and coated vesicles. An additional source of plain synaptic vesicles are the tubular cisternae. Exocytosis of plain synaptic vesicles constitutes the mechanism by which transmitter is released from the presynaptic terminal.     

Vibrations as an experimental factor affecting intestinal resorption

The authors treated white rats daily at one and the same time for a period of one hour with vibrations. One of the groups of animals were treated with vibrations and examined after that, but the other two groups were treated respectively for 45 and 90 days. Examination was carried out during vibration, immediately after that and three hours after the vibrations. They used the method of the turned bags of Wilson and Waisman, by means of which they checked the resorption of glucose through the intestinal wall in vitro, it was established that during continuous vibration action the values of the resorption glucose were statistically lower than those of the control group. There were statistically significant differences in the values of the resorbed glucose in the subgroups examined during the vibration immediately and there hours after that. The authors discuss the obtained results in the light of the current concepts for the action of vibrations as a stress factor and their influence on intestinal resorption.     

Basic fibroblast growth factor as one of the essential factors regulating lens transdifferentiation of pigmented epithelial cells

In vitro transdifferentiation of retinal pigmented epithelial cells of the chick embryo into lens cells can be markedly enhanced by culture in the presence of testicular hyaluronidase and phenylthiourea. Since the commercial preparations of hyaluronidase that had previously been used were very crude, a search for the actual effective molecule(s) enhancing lens transdifferentiation was conducted. First, we purified the enzyme and tested the effect of the purified hyaluronidase. Highly purified hyaluronidase itself did not enhance lens transdifferentiation. The crude hyaluronidase was then separated according to affinity with heparin, considering the possibility that the fibroblast growth factor (FGF) is contained in the crude hyaluronidase. Transdifferentiation-enhancing activity was detected in the fraction which was bound to heparin and eluted with 2 M NaCl, where no hyaluronate-degrading activity existed. Analysis of the fraction by SDS-PAGE revealed the existence of an 18 kDa protein whose NH2-terminal sequence was identical to that of basic FGF. The basic FGF derived from bovine brain also enhanced lens transdifferentiation of pigmented epithelial cells. These findings suggest that basic FGF must play a major role in enhancing transdifferentiation of pigmented epithelial cells to lens cells.     

Role of decay-accelerating factor in regulating complement activation on the erythrocyte surface as revealed by gene targeting

Decay-accelerating factor (DAF) is a glycosylphosphatidylinositol (GPI)-anchored membrane protein that inhibits both the classical and the alternative pathways of complement activation. DAF has been studied extensively in humans under two clinical settings: when absent from the erythrocytes of paroxysmal nocturnal hemoglobinuria (PNH) patients, who suffer from complement-mediated hemolytic anemia, and in transgenic pigs expressing human DAF, which have been developed to help overcome complement-mediated hyperacute rejection in xenotransplantation. Nevertheless, the exact role of DAF in regulating complement activation in vivo on the cell surface and the species specificity of this molecule remain to be fully characterized. To address these issues, we have used gene targeting to produce mice lacking GPI-anchored DAF. We found that erythrocytes from mice deficient in GPI-anchored DAF showed no increase in spontaneous complement activation in vivo but exhibited impaired regulation of zymosan-initiated bystander and antibody-triggered classical pathway complement activation in vitro, resulting in enhanced complement deposition. Despite a high level of C3 fixation, no homologous hemolysis occurred. It is noteworthy that GPI-linked DAF knockout erythrocytes, when tested with human and guinea pig sera, were more susceptible to heterologous complement lysis than were normal erythrocytes. These results suggest that DAF is capable of regulating homologous as well as heterologous complement activation via the alternative or the classical pathway. They also indicate that DAF deficiency alone is not sufficient to cause homologous hemolysis. In contrast, when the assembly of the membrane-attack complex is not properly regulated, as in the case of heterologous complement activation or in PNH patients, impaired erythrocyte DAF activity and enhanced C3 deposition could lead to increased hemolytic reaction.     

The ups and downs of Hebb synapses.

Modelers have come up with many different learning rules for neural networks. When a teacher specifies the correct output, error-driven rules work better than pure Hebb rules in which the changes in synapse strength depend on the correlation between pre and postsynaptic activities. But for unsupervised learning, Hebb rules can be very effective if they are combined with suitable normalization or "unlearning" terms to prevent the synapses growing without bound. Hebb rules that use rates of change of activity instead of activity itself are useful for discovering perceptual invariants and may also provide a way of implementing error-driven learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The brain as a symbol-processing machine

The knowledge accumulated about the biochemistry of the synapsis in the last decades completely changes the notion of brain processing founded exclusively over an electrical mechanism, toward that supported by a complex chemical message exchange occurring both locally, at the synaptic site, as well as at other localities, depending on the solubility of the involved chemical substances in the extracellular compartment. These biochemical transactions support a rich symbolic processing of the information both encoded by the genes and provided by actual data collected from the surrounding environment, by means of either special molecular or cellular receptor systems. In this processing, molecules play the role of symbols and chemical affinity shared by them specifies the syntax for symbol manipulation in order to process and to produce chemical messages. In this context, neurons are conceived as message-exchanging agents. Chemical strings are produced and stored at defined places, and ionic currents are used to speed up message delivery. Synaptic transactions can no longer be assumed to correspond to a simple process of propagating numbers powered by a factor measuring the presynaptic capacity to influence the postsynaptic electrical activity, but they must be modeled by more powerful formal tools supporting both numerical and symbolic calculations. It is proposed here that formal language theory is the adequate mathematical tool to handle such symbolic processing. The purpose of the present review is therefore: (a) to discuss the relevant and recent literature about trophic factors, signal transduction mechanisms, neuromodulators and neurotransmitters in order (b) to point out the common features of these correlated processes; and (c) to show how they may be organized into a formal model supported by the theory of fuzzy formal languages (d) to model the brain as a distributed intelligent problem solver.