[Magnetocardiography in clinical practice: algorithms and technologies for data analysis].

This methodological work is the first part of series of papers dedicated to the modern perspective method of non-invasive diagnostics in cardiology--magnetocardiography. Definition of magnetocardiography method is given, levels of magnetocardiography data analysis as well as electrophysiological models are described. The most informative biomarkers and technologies of qualitative and quantitative interpretation of current density distribution maps and curves of total current magnitude are presented. The step-by-step algorithm, which was used for the MCG-data analysis, is proposed.

[Computer analysis of erythrocyte catalase activity in diagnosis of mild brain trauma and concussion].

A complex investigation of catalase activity in erythrocytes was conducted basing on the results of computer quantitative morphometry of histochemical examination of blood samples from persons with mild craniocerebral trauma. It was found that erythrocytic catalase activity correlates with severity of brain trauma. A novel technique of objective histochemical diagnosis of trauma is described. It provides objective grounds for expert conclusions. Differential features of erythrocytic shape were defined in a small series of micropreparations vs the rest blood samples.

DLG differentially localizes Shaker K+-channels in the central nervous system and retina of Drosophila.

Subcellular localization of ion channels is crucial for the transmission of electrical signals in the nervous system. Here we show that Discs-Large (DLG), a member of the MAGUK (membrane-associated guanylate kinases) family in Drosophila, co-localizes with Shaker potassium channels (Sh Kch) in most synaptic areas of the adult brain and in the outer membrane of photoreceptors. However, DLG is absent from axonal tracts in which Sh channels are concentrated. Truncation of the C-terminal of Sh (including the PDZ binding site) disturbs its pattern of distribution in both CNS and retina, while truncation of the guanylate kinase/C-terminal domain of DLG induces ectopic localization of these channels to neuronal somata in the CNS, but does not alter the distribution of channels in photoreceptors. Immunocytochemical, membrane fractionation and detergent solubilization analysis indicate that the C-terminal of Sh Kch is required for proper trafficking to its final destination. Thus, several major conclusions emerge from this study. First, DLG plays a major role in the localization of Sh channels in the CNS and retina. Second, localization of DLG in photoreceptors but not in the CNS seems to depend on its interaction with Sh. Third, the guanylate kinase/C-terminal domain of DLG is involved in the trafficking of Shaker channels but not of DLG in the CNS. Fourth, different mechanisms for the localization of Sh Kch operate in different cell types.

[Significance of histochemical parameters of erythrocyte catalase activity for diagnosing mild concussion and contusion of the brain]. / Znachenie gistokhimicheskikh pokazatelei katalaznoi aktivnosti éritrotsitov dlia diagnostiki sotriaseniia i ushiba golovnogo mozga legkoé stepeni.

A total of 227 primary and repeated forensic medical expert conclusions in victims with slight craniocerebral injuries (CCI) are analyzed. Erythrocyte catalase (CTer) activity was analyzed on the basis of the results of computer quantitative morphometry of histochemical analysis of blood smears from 50 victims with slight CCI. CTer activity correlated with the severity of CCI. A new objective method for histochemical diagnosis of slight concussion and contusion of the brain is suggested, which rules out errors in forensic medical expert evaluations in examinations of this category of victims.

Synaptic targeting and localization of discs-large is a stepwise process controlled by different domains of the protein.

BACKGROUND: Membrane-associated guanylate kinases (MAGUKs) assemble ion channels, cell-adhesion molecules and components of second messenger cascades into synapses, and are therefore potentially important for co-ordinating synaptic strength and structure. Here, we have examined the targeting of the Drosophila MAGUK Discs-large (DLG) to larval neuromuscular junctions. RESULTS: During development, DLG was first found associated with the muscle subcortical compartment and plasma membrane, and later was recruited to the postsynaptic membrane. Using a transgenic approach, we studied how mutations in various domains of the DLGprotein affect DLG targeting. Deletion of the HOOK region-the region between the Src homology 3 (SH3) domain and the guanylate-kinase-like (GUK) domain-prevented association of DLG with the subcortical network and rendered the protein largely diffuse. Loss of the first two PDZ domains led to the formation of large clusters throughout the plasma membrane, with scant targeting to the neuromuscular junction. Proper trafficking of DLG missing the GUK domain depended on the presence of endogenous DLG. CONCLUSIONS: Postsynaptic targeting of DLG requires a HOOK-dependent association with extrasynaptic compartments, and interactions mediated by the first two PDZ domains. The GUK domain routes DLG between compartments, possibly by interacting with recently identified cytoskeletal-binding partners.

Drosophila larval neuromuscular junction: molecular components and mechanisms underlying synaptic plasticity.

Understanding the mechanisms that mediate synaptic plasticity is a primary goal of molecular neuroscience. The Drosophila larval neuromuscular junction provides a particularly useful model for investigating the roles of synaptic components in both structural and functional plasticity. The powerful molecular genetics of this system makes it possible to uncover new synaptic components and signaling molecules, as well as their function in the intact organism. Together with the mouse hippocampus and Aplysia dissociated cell culture, the Drosophila larval neuromuscular junction has been among the most valuable model systems for examining the molecular and cellular basis of neuronal plasticity.

The Drosophila beta-amyloid precursor protein homolog promotes synapse differentiation at the neuromuscular junction.

Although abnormal processing of beta-amyloid precursor protein (APP) has been implicated in the pathogenic cascade leading to Alzheimer's disease, the normal function of this protein is poorly understood. To gain insight into APP function, we used a molecular-genetic approach to manipulate the structure and levels of the Drosophila APP homolog APPL. Wild-type and mutant forms of APPL were expressed in motoneurons to determine the effect of APPL at the neuromuscular junction (NMJ). We show that APPL was transported to motor axons and that its overexpression caused a dramatic increase in synaptic bouton number and changes in synapse structure. In an Appl null mutant, a decrease in the number of boutons was found. Examination of NMJs in larvae overexpressing APPL revealed that the extra boutons had normal synaptic components and thus were likely to form functional synaptic contacts. Deletion analysis demonstrated that APPL sequences responsible for synaptic alteration reside in the cytoplasmic domain, at the internalization sequence GYENPTY and a putative G(o)-protein binding site. To determine the likely mechanisms underlying APPL-dependent synapse formation, hyperexcitable mutants, which also alter synaptic growth at the NMJ, were examined. These mutants with elevated neuronal activity changed the distribution of APPL at synapses and partially suppressed APPL-dependent synapse formation. We propose a model by which APPL, in conjunction with activity-dependent mechanisms, regulates synaptic structure and number.

Regulation of DLG localization at synapses by CaMKII-dependent phosphorylation.

Discs large (DLG) mediates the clustering of synaptic molecules. Here we demonstrate that synaptic localization of DLG itself is regulated by CaMKII. We show that DLG and CaMKII colocalize at synapses and exist in the same protein complex. Constitutively activated CaMKII phenocopied structural abnormalities of dlg mutant synapses and dramatically increased extrajunctional DLG. Decreased CaMKII activity caused opposite alterations. In vitro, CaMKII phosphorylated a DLG fragment with a stoichiometry close to one. Moreover, expression of site-directed dlg mutants that blocked or mimicked phosphorylation had effects similar to those observed upon inhibiting or constitutively activating CaMKII. We propose that CaMKII-dependent DLG phosphorylation regulates the association of DLG with the synaptic complex during development and plasticity, thus providing a link between synaptic activity and structure.

The gene mod(mdg4) affects synapse specificity and structure in Drosophila.

The mechanisms by which synapse assembly and maturation are orchestrated during development are largely unknown. We used P-element mutagenesis and a larval anatomical screen to isolate mutants in which synapse structure was altered. Here, we describe a mutation isolated with this screen, branch point disrupted (bpd), in which both synapse specificity and synapse morphology were altered. Synaptic terminals in bpd mutants developed abnormally, forming multiple branch points, overgrowing to inappropriate neighboring muscles, and establishing aberrant folding of postsynaptic membranes. Ultrastructural characterization of synaptic boutons in bpd demonstrated abnormal layering of the postsynaptic specialization or subsynaptic reticulum (SSR). Genetic and molecular analyses revealed that bpd is an allele of mod(mdg4), a gene coding for a protein with many similarities to transcription factors, which has been implicated in the regulation of chromatin insulation. Our results suggest that mod(mdg4) may regulate a gene(s) essential to normal synapse formation.

[Changes in regional hemodynamics indices in patients with open-angle glaucoma]. / Izmenenie pokazatelei regional'noi gemodinamiki u bol'nykh otkrytougol'noi glaukomoi.

Changes in the hemodynamic parameters of the eye were examined in patients with primary open-angle glaucoma (OAG) in the well developed and far advanced stages with moderately increased (up to 32 mm Hg) and high (33 mm Hg and higher) pressure before and after surgery. Computer-aided vacuum ophthalmodynamometer was used with a sucking cup calibrated for two levels of ophthalmic tone, whose external diameter was 13 mm and funnel angle 60 degrees. A total of 59 patients (82 eyes) aged 50 to 84 years were examined, control group consisted of 18 patients (36 eyes). Mean dynamic pressure in the orbital artery and perfusion pressure were measured, and the orbital-brachial coefficient estimated. Progressive decrease of perfusion pressure was paralleled by increase of the mean dynamic pressure in the orbital artery in patients with stages Iic and IIIb OAG and by its decrease in those with stage IIIc OAG. Such changes of the hemodynamics are explained by the compensatory work of the ocular bloodflow autoregulation mechanism in the first case and its failure in the second. After regression analysis, linear equations of the relationship between changes in the mean dynamic pressure and intraocular pressure were calculated. After surgery, changes in the hemodynamic parameters were followed up for 12 months in 27 eyes with well-developed condition and for 6 months in 13 eyes with far advanced condition.

Synaptic vesicle size and number are regulated by a clathrin adaptor protein required for endocytosis.

Clathrin-mediated endocytosis is thought to involve the activity of the clathrin adaptor protein AP180. However, the role of this protein in endocytosis in vivo remains unknown. Here, we show that a mutation that eliminates an AP180 homolog (LAP) in Drosophila severely impairs the efficiency of synaptic vesicle endocytosis and alters the normal localization of clathrin in nerve terminals. Most importantly, the size of both synaptic vesicles and quanta is significantly increased in lap mutants. These results provide novel insights into the molecular mechanism of endocytosis and reveal a role for AP180 in regulating vesicle size through a clathrin-dependent reassembly process.

Synaptic clustering of the cell adhesion molecule fasciclin II by discs-large and its role in the regulation of presynaptic structure.

The cell adhesion molecule Fasciclin II (FASII) is involved in synapse development and plasticity. Here we provide genetic and biochemical evidence that proper localization of FASII at type I glutamatergic synapses of the Drosophila neuromuscular junction is mediated by binding between the intracellular tSXV bearing C-terminal tail of FASII and the PDZ1-2 domains of Discs-Large (DLG). Moreover, mutations in fasII and/or dlg have similar effects on presynaptic ultrastructure, suggesting their functional involvement in a common developmental pathway. DLG can directly mediate a biochemical complex and a macroscopic cluster of FASII and Shaker K+ channels in heterologous cells. These results indicate a central role for DLG in the structural organization and downstream signaling mechanisms of cell adhesion molecules and ion channels at synapses.

[Perikom, a static automated perigraph, some aspects of prospective standardization of perimetric studies]. / Staticheskii avtomaticheskii perigraf "Perikom". Nekotorye aspekty perspektivnoi standartizatsii perimetricheskikh issledovanii.

Discusses the functional and operation potentialities of a modern static automated perigraph PERIKOM intended for investigating the visual field and detecting scotomas of different severity. Presents the basic aspects of standardization of perimetric studies in medical institutions of different levels.

Essential role for dlg in synaptic clustering of Shaker K+ channels in vivo.

The assemblage of specific ion channels and receptors at synaptic sites is crucial for signaling between pre- and postsynaptic cells. However, the mechanisms by which proteins are targeted to and clustered at synapses are poorly understood. Here we show that the product of the Drosophila discs-large gene, DLG, is colocalized with Shaker K+ channels, which are clustered at glutamatergic synapses at the larval neuromuscular junction. In heterologous cells, DLG can cluster Shaker-type K+ channels, and, in the yeast two-hybrid system, the DLG PDZ1-2 domains bind directly to the C-terminal tail of Shaker proteins. We also demonstrate that DLG-Shaker interactions are required in vivo for Shaker clustering at the neuromuscular junction. Synaptic clustering of Shaker channels is abolished not only by mutations in dlg but also by a mutation in Shaker that deletes its C-terminal DLG binding motif. Analyses of various dlg mutant alleles suggest that channel clustering and synaptic targeting functions depend on distinct DLG domains. These studies demonstrate for the first time that DLG plays an important role in synaptic organization in vivo that correlates with its ability to bind directly to specific membrane proteins of the synapse.

Synapse maturation and structural plasticity at Drosophila neuromuscular junctions.

The Drosophila larval neuromuscular junction has recently emerged as a powerful model system to characterize the cellular and molecular events involved in the formation and flexibility of synapses. The combination of molecular, genetic, electrophysiological and anatomical approaches has revealed, for example, the functional significance of the discs-large gene product (a novel synapse-organizing protein) in the nervous system. This protein is involved in the clustering of at least one ion channel and in the structural modification of glutamatergic synapses during target muscle growth. The manipulation of the genes encoding ion channels, components of second-messenger cascades, and cell adhesion molecules is beginning to tease apart the mechanisms underlying structural synaptic plasticity.

Regulation of synapse structure and function by the Drosophila tumor suppressor gene dlg.

Mutations of the tumor suppressor gene discs-large (dlg) lead to postsynaptic structural defects. Here, we report that mutations in dlg also result in larger synaptic currents at fly neuromuscular junctions. By selectively targeting DLG protein to either muscles or motorneurons using Gal-4 enhancer trap lines, we were able to rescue substantially the reduced postsynaptic structure in mutants. Rescue of the physiological defect was accomplished by presynaptic, but not postsynaptic targeting, consistent with our finding that miniature excitatory junctional currents were not changed in dlg mutants. These results suggest that DLG functions in the regulation of neurotransmitter release and postsynaptic structure. We propose that DLG is an integral part of a mechanism by which changes in both neurotransmitter release and synapse structure are accomplished during development and plasticity.

The Drosophila tumor suppressor gene, dlg, is involved in structural plasticity at a glutamatergic synapse.

BACKGROUND: Synaptic contacts between neurons and their targets are dynamic entities that can change depending on developmental and functional states of the pre- and postsynaptic cell. However, the molecular factors involved in this plasticity have remained largely unknown. We have demonstrated previously that the Drosophila tumor suppressor gene, discs-large (dlg), is expressed at neuromuscular synapses, and is required for normal synapse structure. A family of dlg homologues is also expressed at mammalian synapses, where they interact with the N-methyl-D-aspartate receptor and ion channels. Here, we provide the first demonstration of the involvement of dlg in structural synaptic plasticity during postsynaptic target growth. RESULTS: We used a temperature-sensitive dlg allele to demonstrate that there are two stages, late embryogenesis and larval stages, at which dlg is necessary for normal formation of synapses. These stages are coincident with dynamic DLG expression at presynaptic sites in the late embryo, and at postsynaptic regions in the larva. Ultrastructural and confocal analyses reveal that Drosophila neuromuscular junctions undergo a dramatic expansion of the postsynaptic apparatus, which is paralleled by target muscle growth. We show that this process of postsynaptic expansion is partially blocked in dlg mutants. CONCLUSIONS: Our results demonstrate that dlg is required during synapse maturation. We show that dlg is involved in the determination of postsynaptic size during target muscle growth. Because motoneuron targets in the larva are continuously growing, synaptic contacts are structurally plastic, undergoing continuous expansion. We conclude that dlg plays an important role in this form of structural synaptic plasticity.

Octopamine immunoreactivity in the fruit fly Drosophila melanogaster.

Octopamine has been proposed as a neurotransmitter/modulator/hormone serving a variety of physiological functions in invertebrates. We have initiated a study of octopamine in the fruit fly Drosophila melanogaster, which provides an excellent system for genetic and molecular analysis of neuroactive molecules. As a first step, the distribution of octopamine immunoreactivity was studied by means of an octopamine-specific antiserum. We focused on the central nervous system (CNS) and on the innervation of the larval body wall muscles. The larval octopamine neuronal pattern was composed of prominent neurons along the midline of the ventral ganglion, whereas brain lobes were devoid of immunoreactive somata. However, intense immunoreactive neuropil was observed both in the ventral ganglion and in the brain lobes. Some of the immunoreactive neurons sent peripheral fibers that innervated most of the muscles of the larval body wall. Octopamine immunoreactivity was observed at neuromuscular junctions in all larval stages, being present in a well-defined subset of synaptic boutons, type II. Octopamine immunoreactivity in the adult CNS revealed many additional neurons compared to the larval CNS, indicating that at least a subset of adult octopamine neurons may differentiate during metamorphosis. Major octopamine-immunoreactive neuronal clusters and neuronal processes were observed in the subesophageal ganglion, deutocerebrum, and dorsal protocerebrum, and intense neuropil staining was detected primarily in the optic lobes and in the central complex.

The Drosophila tumor suppressor gene dlg is required for normal synaptic bouton structure.

The Drosophila tumor suppressor gene lethal (1) discs large (dlg) encodes a protein necessary for normal cell growth in epithelial and brain tissue. It shares high sequence identity to the mammalian synaptic proteins PSD-95 and SAP-70, whose functions are unknown. To determine the localization and role of dlg at synapses, we investigated its distribution and the effects of dlg mutations on Drosophila neuromuscular junctions. We show that dlg immunoreactivity is expressed at one type of glutamatergic synapse and is associated with both presynaptic and postsynaptic membranes. Mutations in dlg alter the expression of dlg and cause striking changes in the structure of the subsynaptic reticulum, a postsynaptic specialization at these synapses. These results indicate that dlg is required for normal synaptic structure and offer insights regarding the role of dlg homologs at vertebrate synapses.