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A whispering gallery mode (WGM) semiconductor laser with a convex disk cavity operating at room temperature in the middle-IR range (λ = 2.4 μm) has been created for the first time. The convex cavity was formed by etching in a specially selected CrO3-HF-H2O mixture. The room-temperature emission spectra have been measured. The laser generates WGMs at room temperature in a pulsed regime.

Whispering gallery modes (WGMs) have been observed in lasers with cut disk (half-and quarterdisk) cavities operating at room temperature in the 2.0–2.4 μm wavelength range. The possibility of WGM generation in a disk-sector cavity is theoretically studied. It is established that the intermode distance in a full-and half-disk cavity is the same, while that in the quarter-disk cavity is doubled. A new method for the radiation extraction from WGM lasers is proposed.

Electrochemical etching in an HClO4-CH3COOH mixture has been used for the formation of disk cavities intended for a whispering-gallery-mode semiconductor laser. The isotropic etching of layers in a heterostructure based on InAs and a related InAsSb0.14P0.3 quaternary solid solution allowed us to obtain perfect round mesas with diameters from 275 to 50 μm. At a total etching depth reaching 15 μm, the vertical part of the side surface was about 7 μm.

New possibilities of scanning electron microscopy, using secondary-and reflected-electron signals, for determining the position of heteroboundaries in long-wavelength laser structures are reported. The formation of the indicated signals in structures of mid-infrared-range lasers of a new type based on type-II GaInAsSb/InGaAsSb heterostructures as well as in the conventional InAsSb/InAsSbP heterostructures is analyzed. The observed characteristic features of the formation of secondary-and reflected-electron signals in these structures as compared with the well-studied AlGaAs/GaAs structures are explained. The results obtained are necessary for accurate determination of an important laser parameter — the position of the p-n junction. It is shown that it is best to use the reflected-electron signal.

The characteristic features of the continuous-wave lasing spectra near 3.3 µm of multimode InAsSbP/InAsSb/InAsSbP double-heterostructure diode lasers are shown. The observation of mode switching to longer and shorter wavelengths at cryogenic temperatures is reported. It is shown that suppression of the longitudinal side modes closest to the main mode results in large mode jumps in energy during mode tuning by current. The characteristics which were observed are explained by gain spectrum inhomogeneity due to spectral hole burning in narrow-gap semiconductors. The intraband charge-carrier relaxation times in the active region are estimated.

The electrical properties of GaSb and solid solutions based on it (GaInAsSb, GaAlSb, GaAlAsSb) have been investigated. It is shown that the current-carrier concentration and mobility in all these materials are determined mainly by VGaGaSb structural defects, with their concentration decreasing almost linearly with decrease of the GaSb content of the solid solution. The dependence of the parameters of the solid solutions on the concentration of these structural defects is determined. The possibility of reducing their concentration by using the neutral solvent Pb and rare-earth elements is demonstrated.

The far-zone directional pattern of diode mesastrip lasers with a 10 µm wide strip has been investigated as a function of the current. The directional pattern in the plane of the p-n junction contains one longitudinal mode, whose width depends on the current. It is shown by comparing the theoretically computed and experimentally measured spatial modes that this dependence is determined by the variation of the light flux intensity and the free-carrier density distributions over the strip width as a function of the current. In the case when the distributions are close to uniform the maximum narrow spatial longitudinal mode and a unimodal radiation spectrum are observed.

We have produced, by using liquid-phase epitaxy, 2.7 to 3.0-µm lasers based on InAsSbP double-heterostructures with different phosphorus contents in the active and wide-gap regions. The lasers possess threshold current density ∼0.8 kA/cm2 at 77 K and operate in the pulsed mode up to ∼124 K with maximum threshold current density 10–12 kA/cm2. The lasers have a low series resistance ∼0.45 Ω.

Diode lasers based on InAsSb/InAsSbP with separate electrical and optical confinement, emitting in the wavelength interval 3–4 µm, are investigated. The lasers attain a higher operating temperature when electrical confinement is created by means of type-II heterojunctions. Interface Auger recombination is suppressed in lasers of this type, and the experimental current density is close to the theoretically calculated value for the case of predominant volume Auger recombination at a temperature of 180–220 K.

The dynamics of long-term memory retrieval on the 1st and 5th days after rat training in spatial Morris water maze and snail conditioned taste aversion models was studied. It was found that animals trained for several days displayed stable and high level of memory retrieval both on 1st and on 5th days after training. Under conditions of single-session training the rate of memory retrieval in snails and rats on the 5th day was higher than on the 1st day after training. It has been proposed that spontaneous enhancement of habit retrieval during 5-days time interval after training is a result of "lingering" memory consolidation processes, which includes trace reorganization in particular molecular and morphological changes in animal brain neurons.

IR radiation sources representing optically coupled semiconductor disk lasers with active regions based on quantum-confined GaInAsSb/AlGaAsSb heterostructures have been created. It is shown that this system ensures single-mode generation in optically coupled cavities operating on whispering gallery modes (WGMs). Conditions for WGM lasing are determined as dependent on the distance between two optically coupled disk cavities.

The polarization of lasing and spontaneous emission from half-disk- and disk-shaped quantum-confinement lasers operating on whispering-gallery modes with wavelengths within 2.18–2.28 μm has been studied. It is established that electric vector E of output radiation is oriented predominantly in the p-n junction plane, which is explained by the fact that radiation is generated due to electron-heavy hole transitions. Modulation of the polarized spontaneous radiation spectra has been observed.

Effect of administration of selective N-methyl-D-aspartate (NMDA) receptor antagonist Ro 25-6981 on learning and memory in a dose which is known to stimulate neoneurogenesis was assessed in adult rats with different abilities to formation of spatial skills in different time periods after the antagonist injection. Wistar male rats were trained to find hidden platform in the Morris water maze for 5 consecutive days. Rats' learning ability for spatial skill formation was evaluated depending on platform speed achievements. In re-training sessions (cues and platform location changed), it was found that all rats received Ro 25-6981 13 days before the re-training demonstrated impaired spatial memory. At the same time the inhibitor injected 29 days before re-training selectively facilitated the formation of spatial skill in animals with initially low learning abilities.

Directivity patterns of disk-shaped whispering gallery mode (WGM) semiconductor lasers based on quantum-confined AlGaAsSb/InGaAsSb nanoheterostructures have been studied. The cavities of disk lasers were manufactured by wet chemical etching and had the shape of a truncated cone with a height of 15 μm. The top (about 5-μm-high) part of the cavity had a cylindrical shape. A flat ring with a width equal to the thickness of the active region was protruding ∼1 μm out of the side face of the cavity. The directivity diagram of the disc WGM laser exhibits a ring-shaped interference pattern with several maxima separated by an angle of ∼6°. The interference pattern observed in both spontaneous and laser generation regimes can be explained by the interference of rays emitted directly from the ring and those reflected from the etched surface of the crystal.

Frequency tunable infrared whispering gallery mode (WGM) semiconductor laser with a disk cavity has been created that operates at a wavelength of 3.5 μm at a temperature of 79 K. The laser radiation spectra have been studied. Smooth tuning of the main WGM toward shorter wavelengths by 11 A due to nonlinear optical effects has been observed.

On the basis of the InAsSb/InAsSbP double heterostructure, lasers with a thick active region (3 µm) and a wide cavity (40 µm) were fabricated that operated near 3.3 µm and were intended for obtaining a low radiation divergence in the p-n-junction plane. Laser emission spectra and radiation patterns for different cur-rents were studied. The current-induced shift of the laser emission line reaches 24 A. The half-width of the radiation pattern is 9° in the p-n-junction plane and 63° in the perpendicular plane. The experimental data on the radiation pattern are compared with the theoretical results expected in the case where two in-phase waves with the same amplitude are formed in a cavity.

An InAs0.89Sb0.11 photovoltaic detector that operates at room temperature in the 2.5-5 mu m mid-infrared wavelength region is reported. The photodiode has an extended spectral response compared with other currently available III-V room-temperature detectors. In order to accommodate the large lattice mismatch between the InAs0.89Sb0.11 active region and the InAs substrate, a buffer layer with an intermediate composition was introduced into the structure. In this way, we obtained room-temperature photodiodes with a cutoff wavelength near 5 mu m, a peak responsivity of 0.8 A/W, and a detectivity of 1.26 x 10(9) cm Hz(1/2)/W. These devices could be effectively used as the basis of an optical sensor for the environmental monitoring of carbon monoxide at 4.6 mu m, or as a replacement for PbSe photoconductors. (C) 2000 American Institute of Physics. [S0003-6951(00)02332-9].

A cross-sectional mass epidemiological survey of 18,320 urban and rural citizens of the Republic of Tadjikistan revealed 31 patients with orbital tumors, of which lacrimal neoplasms were determined in 4 (0.022% in the general population and 12.9% of the identified orbital tumors). According to the referral data, the prevalence of lacrimal neoplasms was 1.03% of all the tumors of the organ of vision and 5.26% of the orbital neoplasms. Epithelial tumors were more common (52%), their malignant forms dominated over benign ones (55.7% versus 44.3%). Inflammatory processes (22.6%) as acute and chronic dacryoadenitis (9.5%) and pseudotumors (13.1) were the second most common conditions. Lymphoid tissue tumors (13.6%), cystoid masses (8.6%), and neoplasms of unclear genesis (1.4%) were noticeably less prevalent. The severest difficulties in recognizing lacrimal epithelial tumors were to clinically and morphologically identify what determined the specific features of the lacrimal structure and evident structural polymorphism. With the higher grade of anaplasia, the likelihood of a recurrence of a tumor and the rate of its growth increased (r = +0.83). The survival rates closely correlated with the higher rates of recurrent adenocarcinoma and adenocystic cancer (r = -0.87).

The effects of two 5-membered (SP5, SP6) endogenous synthetic peptide fragments of protein S100b on the course of regenerative-reparative processes in the corneas of Wistar rats were morphologically studied after making a graduated injury. Conjunctival or endonasal injection of the peptides was made at two concentrations of 10(-6) and 10(-8) M. The study peptides were found to have a modulating effect on regenerative-reparative processes regardless of the route of administration and to induce accelerated and qualitative corneal wound healing as compared with the controls. The specific feature of SP5 was the formation of a fibroblastic membrane. When SP5 was injected at a concentration of 10(-6) M, the membrane was more pronounced and occupied the whole area of keratectomy whereas when this peptide was administered at a concentration of 10(-8) M, its formation was observed in the deep and middle corneal layers. The most marked effect of SP6 revealed during the study was the formation of newly-formed vessels over the entire wound surface independently of the concentration of the injected substance. Of the two study peptide fragments, SP5 is, in the authors' opinion, promising for clinical application. Significant keratocytic proliferation noted in the use of SP5 at a concentration of 10(-6) M may be used to accelerate scarring when the sclera and cutaneous covering are damaged. The effects detected with administration of SP6 at two concentrations were regarded as negative as they did not answer the purpose set during the study performed.

The lasing spectra and the shift in the position of the modes in the current range (1–5)I th with various methods of pumping the nonequilibrium charge carriers are analyzed. It is shown that the pumping method does not influence the character of the tuning of the radiation line. The large short-wavelength tuning range (up to 50 A) is due not to the heating of the crystal lattice in the active-region material but rather the nonuniform nonequilibrium charge-carrier density distribution over the width of the stripe.

Effects of caspase inhibitors injected intracerebroventricularly or applicated to cerebellar vermis of adult rats on different types of learning and memory were studied. Pancaspase inhibitor z-VAD-fmk introduced into lateral cerebral ventriculi enhanced elaboration of long-term spatial memory in Morris water maze and stimulated habit alteration at the early stage of its formation. Caspase-3 inhibitor z-DEVD-CHO applied to cerebellar vermis enhanced the elaboration of acoustic startle habituation but had no effect on its storage and retrieval. These results indicate caspase participation in mechanisms of learning and memory both through influence on coupled processes of neurogenesis-apoptosis and through modulation of synaptic efficiency.

The neuroprotective effect of choline succinate was studied in rats with chronic cerebral ischemia induced by ligation of both common carotid arteries. Two approaches were used to evaluate the neuroprotective effect: cognitive ability tests (passive avoidance test and Morris water maze test) and determination of the brain content of N-acetylaspartate, a marker of functional neurons, by 1H NMR spectroscopy in vivo. Choline succinate administration significantly improved memory and learning in ischemic rats and prevented the ischemia-induced decrease in the cerebral level of N-acetylaspartate. Thus, choline succinate demonstrated a neuroprotective effect in conditions of ischemic brain injury.

Effects of protein synthesis inhibitors on reactivation processes of food aversion conditioning were inverstigated in snail Helix lucorum. Protein synthesis inhibitor (PSI, anisomycin, 0.4 mg, or cycloheximede, 0.6 mg) was injected into snail body cavity 24 hours after 3-day training; then conditioned stimulus (banana) was presented and memory was tested. It was found that 2.5-3 hours after first reminding, associative food conditioning was suppressed, recovering of the conditioning was observed 4.5-5.5 hours after first reminding. In other group of snails, PSI injections were single (1.8 mg) or triple (0.6 mg with 2-hour interval). Reminding stimulus was presented after each injection. In this case, suppression of food aversion conditioning was also observed 2.5-3 hours after first reminding, while amnesia in this case lasted over 30 days. Repeated training of the group of snails recovered the food aversion conditioning only partially. In control snails (saline instead of PSI or 3 injections of PSI without reminding), foot aversion conditioning was detected 30 days after first training. Thus we found that PSI effects during reminding of food aversion conditioning produced two phases amnesia: (1) the easily suppressed by PSI transient phase lasted 2-3 hours, and (2) irreversible phase, its suppression by high doses of PSI-initiated amnesia lasting over 1 month. Second phase of amnesia was not recovered after repeated training. It was suggested that reminding induced reconsolidation of initial memory. Its suppression by protein synthesis inhibitors results in erasing of memory trace and disturbs repeated consolidation.

The article covers the results of research into the levels of S100b protein and antibodies to it in the serum of patients with crisis and stable essential hypertension. The results show that neutrophic protein dysmetabolism plays an important role in the pathogenesis of hypertonic dyscirculatory encephalopathy and the forming of cognitive disorder syndrome. The data obtained suggest that hypertensive crises lead to pathologic changes in hematoencephalic barrier permeability and the development of autoimmune reactions with participation of neutrophic proteins.

The main characteristics of room-temperature light-emitting diodes (λ=4.3 μm) based on InAsSbP/InAsSb/InAsSbP III–V semiconductor heterostructures with a variable-gap buffer layer are reported. An optical power P=0.85 mW was achieved with a pulse length of ∼5 μs and 1 kHz repetition frequency. Conditions for maximizing the power of the light-emitting diodes are indicated. An example is given of the use of these diodes to detect carbon dioxide using the 4.3 μm fundamental absorption band.

An etchant having the composition HCl/CrO3 /HF/H2O is proposed for fabricating optoelectronic devices (lasers, light-emitting diodes, and photodiodes) based on InAs solid solutions for the 3–5 μm spectral range. It is shown that the proposed etchant ensures isotropic rates of etching of InAs and GaInAsSb, InAsSPbP, and InAsSb solid solutions of varying composition. An example is given of the use of this etchant to produce high-power light-emitting diodes for the 3.3 μm spectral range.

An investigation was made of continuous tuning of the emission wavelength in two types of InAsSb/InAsSbP diode heterolasers: three-layer structures with combined electrical and optical confinement and five-layer structures with separate confinement. In three-layer structures the emission wavelength initially decreases by 2–4 A with increasing current and then increases by 10–15 A. In five-layer structures the emission wavelength mainly decreases. This difference is attributed to the better flow of carriers in the bulk of the active region in five-layer structures as compared with three-layer ones.

GaAlAsSb/GaInAsSb/GaAlAsSb double-heterostructure LEDs emitting in the region of the 2.35 μm absorption band of methane have been developed for fast gas analyzers. Different designs of double heterostructures based on the solid solution GaInAsSb were studied. Continuous-wave optical power of 1.2 mW was achieved. The methane absorption spectrum for the LED radiation is presented.

InAsSb/InAsSbP double heterostructure diode lasers for the spectral range of 3-4 microm grown by liquid phase epitaxy have been investigated. The laser tuning was studied as a function of the stripe width. The temperature and current tuning of such lasers was measured. Emission spectra, far-field patterns and wavelength tuning versus current have been studied in the wide current range from threshold, Ith, up to 6Ith at liquid nitrogen temperature. Current wavelength tuning in single-mode lasing has been obtained both towards the shorter wavelengths (up to 4.56 cm-1) and towards the longer wavelengths (up to 0.9 cm-1) at the temperature T=77K. Comparison of the emission properties of the lasers, driven by different types of current pulses showed the same quantum-mechanical nature of current tuning. The theoretical model of this nonlinear optical phenomenon is proposed. The estimated times of current tuning defined mainly by the photon lifetime in the cavity are about 10(-9) to 10(-12) s. The emission line-width was determined to be 20 MHz. Optimal conditions were found for the use of the lasers and were employed for the detection of NH3, CH3Cl, OCS and atmospheric water.

The neuroprotective effect of Thr-Gly-Glu-Asn-His-Arg hexapeptide (HLDF-6), a biologically active fragment of the differentiation factor of human leukemia cells (HLDF), was demonstrated on models of Alzheimer's disease in vivo and in vitro. The syndromes of this pathology were induced in male rats by administration of the peptide corresponding to the 25-35 sequence of beta-amyloid peptide (25-35) and ibotenic acid into the hippocampus. HLDF-6 prevented loss of long-term memory and decrease in the orientation-investigation activity of these animals and significantly decreased the number of pyknotic neurons in the CA1 area of the hippocampus. This peptide also exerts a protective effect in vitro on the primary cultures of neurons of the hippocampus and cerebellum of rats under conditions of the beta-amyloid toxicity. An increase in the dihydrotestosterone (DHT) content was demonstrated in the blood plasma of rats with the syndrome of Alzheimer's disease and in the medium of the culture of hippocampus neurons in the presence of the Abeta(25-35) peptide. HLDF-6 inhibited this increase in both cases. A probable mechanism of the neuroprotective effect of HLDF-6 was suggested as being connected to its possible effect on both the biosynthesis and the metabolism of sex steroid hormones.

Activity of caspase-3 and content of DNA fragments with sizes 0.2-0.6 kbp and more than 4.0 kbp in the worm of the cerebellum, hippocampus and prefrontal cortex of the adult rat brain were estimated in 4 and 24 hours after the procedure of acoustic startle habituation and fear conditioning. Heterochronic changes in apoptotic markers in the examined brain structures were observed after training. Caspase-3 activity was decreased in the worm of the cerebellum and hippocampus, and DNA fragmentation was suppressed in the hippocampus and brain cortex. At the same time, both caspase activity and DNA fragmentation were increased in the hypothalamus. These results provide evidence for the involvement of apoptosis in the mechanisms of learning and memory in adult brain.

A decrease in the lasing threshold with increasing temperature has been observed in InAs/InAsSbP laser heterostructures for the 2.7–2.9 μm spectral range at cryogenic temperatures (T=32–85 K). At temperatures below 50 K a negative characteristic temperature, T0=−70 K, was obtained for the threshold current. Characteristics of the temperature dependence of the threshold current and the laser output power were investigated.

High-power light-emitting diodes are demonstrated; they are characterized by a quantum efficiency of 5.5%, utilize a symmetric GaAlAsSb/GaInAsSb/GaAlAsSb double heterostructure, have a spontaneous-emission maximum at a wavelength of 1.94 μm, and operate in the temperature range from −80°C to +60°C. A continuous-wave optical power of 3.7 mW and a peak optical power of 90 mW in pulsed operation (τ∼1–5 ms, f=1 kHz) are attained at room temperature. The principal electrical and emission characteristics are given.

The results of an investigation of the basic electric and power characteristics of 2.0-2.28 μm LEDs for spectroscopic measurements of nitrogen-containing molecules are reported. Room-temperature continuous-mode LEDs were produced from a double symmetric as well as nonsymmetric heterostructure based on the solid solutions GaInAsSb. Continuous-wave optical power ∼1.7 mW of the LED was achieved by optimizing the structure.

Continuous-wave lasing in the 2.2 μm region is reported for single-mode GaAlAsSb/GaSb/GaInAsSb double-heterostructure diode lasers with thermoelectric cooling. The temperature dependences of the threshold current near room temperature are investigated for the cw and pulsed pumping regimes. A record characteristic temperature T0=132 K has been achieved.

New potentials are demonstrated for the application of scanning electron microscope methods to identifying heteroboundaries, monitoring the sharpness of interfaces, and determining the positions of p-n junctions in laser structures based on InAsSb/InAsSbP, including at low temperatures. The method permits optimization of the parameters of long-wavelength lasers and to obtain record low threshold currents (Ith≤25 mA at T=77 K) for lasing wavelengths λ=3–3.5 μm.

Autoimmune processes take place during an acute phase of brain injury as well as during chronic vascular diseases. Cryoglobulinemia is a nonspecific marker of long-term stimulation of the immune system which reflects duration of autoimmune sensitization. It is characterized by production of abnormal temperature-dependent immunoglobulins named cryoglobulins. The highest cryoglobulinemia was found in patients with atherothrombotic stroke that corresponds to the results of previous studies reporting the greatest level of neurospecific antibodies during slow atherothrombosis development. It is shown that cryoglobulinemia is an important factor in pathogenesis of stroke which contributes to microcirculatory and hemorheological disorders, increases blood viscosity and results in the development of immunocomplex endovasculitis of small brain blood vessels in the ischemic lesion.

Clinic-experimental complex investigation and ELISA determination of protein HLDF as also primary antibodies (Abs) to HLDF values in blood and cerebro-spinal fluid (CSF) of patients with hypertensive crises and acute aterotrombotic ischemic stroke were performed. Statistically improved difference in serum HLDF and Abs content in examined patients in comparison with age-matched controls as also significant intergroup's differences in protein and Abs dynamic content were determined. Correlation between content and dynamics of investigated factors in CSF and blood serum with determined clinical and instrumental parameters was revealed. Pathogenetic and prognostic significance of revealed changes in molecular factors was viewed.

Lasing has been obtained near 2.6 μm in double‐heterostructure InGaAs/InAlAs diode lasers grown by metalorganic vapor phase epitaxy on InAs substrates. At 80 K threshold currents are in the range of 40–200 mA for lasers of deep mesa geometry. The characteristic temperature of the temperature dependence of the threshold current T0 is 21–23 K and lasing was achieved up to 150 K in a pulsed regime. A blueshift of up to 3.0 nm with increasing current is observed. A blueshift is also observed with increasing temperature, which is attributed to refractive index change due to the strong temperature dependence of the threshold carrier density in narrow gap III–V semiconductor lasers.

Vital investigation of genome activity and its role in mechanisms of long-term synaptic plasticity formation were studied in LP11 neuron (command neurone of defence behaviour) during sensitisation (simple form of learning) in semi-intact preparation of snail Helix lucorum. Genome activity was investigate by means of specific fluorescent dye SYTO 16 and image analysis system. It was found that application of sensitizing stimulation (10% quinine solution) onto the snail head initiate two-phase changes in neural responses evoked by tactile or chemical stimulation. Depression of neural responses was obtained during short-term phase (during 1 hour after sensitization) and facilitation of neural responses--during long-term phases (over 1 hour). At the same time (15-20 min after learning), a significant increase in SYTO 16 fluorescent level was found in nucleus site LP11 neurone. Initial SYTO 16 fluorescence level was registered in 4-5 hours after sensitization. If the sensitization was produced during actinomycin D application (inhibitor of RNA synthesis, 20 microM) then facilitation of neural responses evoked by sensory stimulation were suppressed during long-term phase of sensitization and was the same as in control sensitized snails during short-term phase of learning. Increase in SYTO 16 fluorescence level in nucleus region site of LP11 neurone was completely prevented in sensitization during actinomycin D application. If actinomycin D was applied 30 min after sensitization (1 hour after first sensitizing stimulation) then synaptic facilitation and fluorescent dynamics was the same as in control sensitized snails. Our experimental data showed that nociceptive sensitization development was followed by quick (15-20 min) DNA activation and long-term synaptic facilitation (1 hour after sensitization), while induction of the processes was suppressed by inhibitor of RNA synthesis during short time interval (during 1 hour of learning).

We have found an increased level of serum antibodies to the prefibrillar structures of both Abeta(25-35) peptide and human lysozyme in Alzheimer's disease (AD) patients compared to age-matched controls, indicating that autoimmunity is implicated in AD. In the serum of AD patients with a long-term duration (15 years) the titer of serum antibodies to aggregates of Abeta(25-35) peptide increased by approximately 5-fold, whilst the antibody titer to lysozyme protofilaments decreased by approximately 8-fold compared to patients with AD duration of5 years. The content of immunoglobulins of the A, G and M types declined, particularly in AD duration of15 years. An increase in the concentration of immune complexes and higher lysozyme activity was detected in the serum of all patients and this was suggestive of an inflammatory reaction. We propose that the autoimmune response to different amyloid structures in AD can be viewed as a clearance pathway targeting amyloid development. Autoimmune response can be exploited as a marker of ongoing protein aggregation and hence be used as a diagnostic feature of AD.

Effects of antibody against serotonin-modulated protein SMP-69 on defence behavior command neurons L-RP11 were studied in semi-intact preparation of snail Helix lucorum. An increase in membrane excitability as well as selective facilitation of neural responses evoked with chemical sensory stimulation of the snail head (0.25-0.5% quinine solution) were determined 1-1.5 hours after antibody application to the neurons. The antibody did not change neural responses evoked with tactile stimulation of the snail head. These effects were similar to those found in L-RP11 neurons after serotonin or cAMP applications as well as after nociceptive sensitization of the snail. It was suggested that protein homologically related the SMP-69 in mammalians was involved in mechanisms of excitability as well as long-term specific plasticity regulation of L-RP11 neurons synaptic inputs from the head chemoreceptors in snail Helix lucorum.

Studies were performed on the involvement of neurotrophic factors in the neurochemical mechanisms of the integrative functions of the brain. The effects of various intrahippocampal doses of antibodies to neurotrophic factors--protein S100 and lectin CSL--were studied on the formation, retention, and reproduction of a habituated acoustic startle response and conditioned fear in adult rats. S100b contents in the hippocampus, hypothalamus, frontal cortex, and cerebellar hemispheres and vermis, and in the basal nuclei were measured in rat brains 0.5, 1, 2, 4, 6, 8, 24, and 48 h after long-term habituation to the startle response. Antibodies to neurotrophic factors had selective and dose-dependent effects on the different memory and learning processes underlying these types of behavior. Changes in S100b in brain structures were seen, which were specific in terms of quantitative levels and dynamics, after acquisition of the behavioral habit. The results obtained here, along with previously reported data on the effects of antibodies to S100b and CSL given into the cerebellum, are discussed as experimental support for the hypothesis of the heterochronous neurochemical organization of integrative brain activity.

The spontaneous electroluminescence emission of InAs light-emitting diodes (LEDs) operating at 3.3 µm was studied as a function of applied hydrostatic pressure. An enhancement of a factor of almost four in radiative efficiency at room temperature was observed in the range 0 to 10 kbar. Analysis of the dependence of electroluminescence emission intensity on hydrostatic pressure at constant current reveals that nonradiative Auger recombination dominates the quantum efficiency of these LEDs.

Effects of idiotypic and antiidiotypic antibodies against protein S100b on synaptic transmission and long-term potentiation of CA1 pyramidal neurons in rat hippocampus were studied. Idiotypic antibodies against protein S100b inhibited synaptic transmission from Schaffer collateral axons to pyramidal neurons, but had no effect on neuronal responses to antidromic stimulation. Antiidiotypic antibodies against protein S100b facilitated neuronal responses to orthodromic stimulation. Idiotypic antibodies against protein S100b suppressed changes in neuronal responses to orthodromic stimulation during long-term potentiation, while antiidiotypic antibodies facilitated these effects. Our findings suggest that the effects of idiotypic and antiidiotypic antibodies to protein S100b are associated with their regulatory influences on synaptic transmission. These mechanisms differ from mechanisms of synaptic plasticity involved in long-term potentiation.

A complex of clinical and immunochemical studies was made in patients with chronic brain ischemia and ischemic stroke and in neonatal infants with CNS dysfunctions and retarded intrauterine development. Enzyme immunoassay was used to measure the levels of brain proteins with trophic properties--S100b, the major protein myelin, lectins CSL, R1, and the levels of primary and antiidiotypic antibodies to these proteins in the biological fluids of the patients. The findings suggest that the study brain proteins and autoimmune processes against these factors are involved in the mechanisms of the pathogenesis of the diseases in question and they enable changes and variations in the levels of neurotropic factors and their autoantibodies to be considered as predictors of brain ischemia and perinatal cerebral lesions.

The effects of antibodies to a total fraction of s100 proteins and protein s100b on the activity of defensive behavior command neurons LP11 and RP11 were studied in common snails, using non-sensitized animals and animals which had acquired nociceptive sensitization. In non-sensitized snails, application of antibodies against s100 or s100b (0.1 mg/ml) induced membrane depolarization, increased membrane permeability, and suppressed slow excitatory postsynaptic potentials in the responses of neurons to sensory stimulation. Acquisition of sensitization in snails in the presence of antibodies to s100 or s100b (0.1 mg/ml) led to significantly less marked facilitation of synaptic transmission and smaller increases in neuron membrane excitability than in cells of control sensitized animals. The difference in synaptic facilitation in the neurons of control sensitized snails and neurons in sensitized snails given antibody was comparable with the magnitude of synaptic depression due to antibody in non-sensitized animals. At a dose of 0.01 mg/ml, antibody had no effect on these measures of neuron activity. It is suggested that s100 proteins, particularly s100b, are involved in the mechanisms regulating excitability, the membrane potential, and synaptic transmission in command neurons in untrained snails, as well as in the mechanism of plasticity of the electrogenic membranes of nerve cells during the acquisition of nociceptive sensitization.

Following elaboration of long-term habituation to a startle-response, antibodies to neurotrophic factor protein S100b exerted selective and dose-dependent influence on different learning processes and memory of learned behavioural patterns in adult rats. S100b increased at all stages of behavioural skill development in hippocampus, hypothalamus, frontal cortex, cerebellar hemispheres and vermis, basal ganglia.