Neural circuit repair by low-intensity magnetic stimulation requires cellular magnetoreceptors and specific stimulation patterns.

Although electromagnetic brain stimulation is a promising treatment in neurology and psychiatry, clinical outcomes are variable, and underlying mechanisms are ill-defined, which impedes the development of new effective stimulation protocols. Here, we show, in vivo and ex vivo, that repetitive transcranial magnetic stimulation at low-intensity (LI-rTMS) induces axon outgrowth and synaptogenesis to repair a neural circuit. This repair depends on stimulation pattern, with complex biomimetic patterns being particularly effective, and the presence of cryptochrome, a putative magnetoreceptor. Only repair-promoting LI-rTMS patterns up-regulated genes involved in neuronal repair; almost 40% of were cryptochrome targets. Our data open a new framework to understand the mechanisms underlying structural neuroplasticity induced by electromagnetic stimulation. Rather than neuronal activation by induced electric currents, we propose that weak magnetic fields act through cryptochrome to activate cellular signaling cascades. This information opens new routes to optimize electromagnetic stimulation and develop effective treatments for different neurological diseases.

Comparing the survival rate of juvenile Chinook salmon migrating through hydropower systems using injectable and surgical acoustic transmitters.

Acoustic telemetry is one of the primary technologies for studying the behavior and survival of fishes throughout the world. The size and performance of the transmitter are key limiting factors. The newly developed injectable transmitter is the first acoustic transmitter that can be implanted via injection instead of surgery. A two-part field study was conducted to evaluate the performance of the injectable transmitter and its effect on the survival of implanted fish. The injectable transmitter performed well and similarly to the proceeding generation of commercially-available JSATS transmitters tested concurrently. Snake River subyearling Chinook salmon smolts implanted with the injectable transmitter had a higher survival probability from release to each of eleven downstream detection arrays, because reach-specific survival estimates were significantly higher for the injectable group in three of the eleven reaches examined. Overall, the injectable group had a 0.263 (SE = 0.017) survival probability over the entire 500 km study area compared to 0.199 (0.012) for the surgically implanted group. The reduction in size and ability to implant the new transmitter via injection has reduced the tag or tagging effect bias associated with studying small fishes. The information gathered with this new technology is helping to evaluate the impacts of dams on fishes.

[Analgesic effects of ionotropic glutamate receptor antagonists MK-801 and NBQX on collagen-induced arthritis rats].

OBJECTIVE: The ionotropic glutamate receptorantagonists include two types: MK-801, antagonist of N-methyl-D-asparticacid (NMDA) receptor, and NBQX, antagonist of non-NMDA receptor.The above-mentioned ionotropic antagonists can block the glutamate and its corresponding receptor binding to produce analgesic effect. The objective of this research was to study two antagonists in analgesic effect on rat behavior,as well as to investigate the down-regulation and up-regulation of cyclooxygenase-2 (COX-2) and Janus-activated kinase (Jak3) in collagen-induced arthritis (CIA) rat serum and tissue fluid after the application of these antagonists, that is, the effect on molecular biology. METHODS: This study used the ionotropic glutamate receptors as the target and established CIA rat model. Vivo studies were used to observe changes in behavior and molecular biology of the CIA rat.Behavioral assessment includedmechanical allodynia and joint swelling in the CIA rat,where themechanical allodynia was measured using the paw-withdrawal threshold (PWT) with VonFrey filaments according to the "Up-Down" method,and the drainage volume was used to assess joint swelling. Then the blood samples taken from the heart of the rat and the tissue homogenate were collected to detect the down-regulation and up-regulation of COX-2 and Jak3 in the serum and tissue fluid after the antagonists wereused. RESULTS: Using MK-801, NBQX alone or using the combination of these two antagonists,these three methods all could alleviate pain(P<0.01).The analgesic effect lasted more than 24 h.Both antagonists reached the peak of analgesia at the end of 4 hours post-injection. NBQX had stronger analgesic effect than MK-801 (P<0.05).Whether alone or combined use of these two antagonists,could not change the CIA rats' swelling of the joint (P>0.05). MK-801 could decrease the expression of COX-2 (P<0.01).At the same time, NBQX did not have this effect (P>0.05). Using MK-801, NBQX alone or combination of these two antagonists could not affect the increased expression of Jak3 caused by the CIA (P>0.05). CONCLUSION: MK-801 and NBQX could both alleviate pain, NBQX was much better than MK-801. Neither MK-801 nor NBQX had the effect on the swelling of the joint. NMDA receptor and COX-2 inflammatory pathways had certain interactions. For Jak3, it could not be found to have cross-function with ionotropic glutamate signaling pathways by this experiment.

A small long-life acoustic transmitter for studying the behavior of aquatic animals.

Acoustic telemetry is an important tool for studying the behavior of aquatic animals and assessing the environmental impact of structures such as hydropower facilities. However, the physical size, signal intensity, and service life of off-the-shelf transmitters are presently insufficient for monitoring certain species. In this study, we developed a small, long-life acoustic transmitter with an approximate length of 24.2 mm, diameter of 5.0 mm, and dry weight of 0.72 g. The transmitter generates a coded acoustic signal at 416.7 kHz with a selectable source level between 159 and 163 dB relative to 1 µPa at 1 m, allowing a theoretical detection range of up to 500 m. The expected operational lifetime is 1 yr at a pulse rate interval of 15 s. The new technology makes long-term acoustic telemetry studies of small fish possible, and is being deployed for a long-term tracking of juvenile sturgeon.

An injectable acoustic transmitter for juvenile salmon.

Salmon recovery and the potential detrimental effects of dams on fish have been attracting national attention due to the environmental and economic implications. In recent years acoustic telemetry has been the primary method for studying salmon passage. However, the size of the existing transmitters limits the minimum size of fish that can be studied, introducing a bias to the study results. We developed the first acoustic fish transmitter that can be implanted by injection instead of surgery. The new injectable transmitter lasts four times longer and weighs 30% less than other transmitters. Because the new transmitter costs significantly less to use and may substantially reduce adverse effects of implantation and tag burden, it will allow for study of migration behavior and survival of species and sizes of fish that have never been studied before. The new technology will lead to critical information needed for salmon recovery and the development of fish-friendly hydroelectric systems.

Design and implementation of a new autonomous sensor fish to support advanced hydropower development.

Acceleration in development of additional conventional hydropower requires tools and methods to perform laboratory and in-field validation of turbine performance and fish passage claims. The new-generation Sensor Fish has been developed with more capabilities to accommodate a wider range of users over a broader range of turbine designs and operating environments. It provides in situ measurements of three-dimensional (3D) linear accelerations, 3D rotational velocities, 3D orientation, pressure, and temperature at a sampling frequency of 2048 Hz. It also has an automatic floatation system and built-in radio-frequency transmitter for recovery. The relative errors of the pressure, acceleration, and rotational velocity were within ±2%, ±5%, and ±5%, respectively. The accuracy of orientation was within ±4° and accuracy of temperature was ±2 °C. The new-generation Sensor Fish is becoming a major technology and being deployed for evaluating the conditions for fish passage of turbines or other hydraulic structures in both the United States and several other countries.

A fast and accurate decoder for underwater acoustic telemetry.

The Juvenile Salmon Acoustic Telemetry System, developed by the U.S. Army Corps of Engineers, Portland District, has been used to monitor the survival of juvenile salmonids passing through hydroelectric facilities in the Federal Columbia River Power System. Cabled hydrophone arrays deployed at dams receive coded transmissions sent from acoustic transmitters implanted in fish. The signals' time of arrival on different hydrophones is used to track fish in 3D. In this article, a new algorithm that decodes the received transmissions is described and the results are compared to results for the previous decoding algorithm. In a laboratory environment, the new decoder was able to decode signals with lower signal strength than the previous decoder, effectively increasing decoding efficiency and range. In field testing, the new algorithm decoded significantly more signals than the previous decoder and three-dimensional tracking experiments showed that the new decoder's time-of-arrival estimates were accurate. At multiple distances from hydrophones, the new algorithm tracked more points more accurately than the previous decoder. The new algorithm was also more than 10 times faster, which is critical for real-time applications on an embedded system.

Oxidized low density lipoprotein and very low density lipoprotein enhance expression of monocyte chemoattractant protein-1 in rabbit peritoneal exudate macrophages.

The migration of monocytes into arterial subendothelial space is one of the earliest events in atherogenesis. Monocyte chemoattractant protein 1 (MCP-1) is a potent monocyte chemoattractant. The purpose of this work was to examine whether oxidized low density lipoprotein (OX-LDL) and very low density lipoprotein (OX-VLDL) have any effect on the expression of MCP-1 mRNA and protein in rabbit peritoneal exudate macrophages. The total RNA was extracted from the macrophages after 24 h exposure to LDL, VLDL, OX-LDL, and OX-VLDL, respectively, and the media (LDL-CM, VLDL-CM, OX-LDL-CM and OX-VLDL-CM) conditioned by the macrophages exposed to the above-mentioned lipoproteins were collected. The MCP-1 mRNA expression in macrophages was examined by Northern blot analysis. Meanwhile, MCP-1 protein in the conditioned media was determined by sandwich ELISA. The chemotactic activity of the conditioned media for monocytes was determined by micropore filter assay. The results revealed that the macrophages can express MCP-1, and 24 h exposure to OX-LDL and OX-VLDL induced a 3.2-fold and a 3.4-fold increase in MCP-1 mRNA expression in macrophages and a 2.2-fold and a 2.5-fold increase in the level of MCP-1 protein in the conditioned media, respectively. However, 24 h exposure to LDL and VLDL only induced a slight increase in the expression of MCP-1 mRNA and protein in macrophages. Furthermore, the migration distance of monocyte induced by OX-LDL-CM and OX-VLDL-CM was longer than that induced by LDL-CM and VLDL-CM, as well as by CM. We conclude that the macrophages can express MCP-1, and OX-VLDL and OX-VLDL induce stronger MCP-1 expression. It suggests that macrophages may amplify the recruitment into subendothelial space, and OX-LDL and OX-VLDL may play an important role in the pathogenesis of atherosclerosis through enhancing the MCP-1 expression in macrophages.

[Smooth muscle cell migration induced by macrophage-derived chemotactic factor].

The chemotactic activity of rabbit peritoneal macrophage condition-medium (M phi-CM) was examined through micropore filter assay. The effects of M phi-CM on smooth muscle cell (SMCS) migration were considered to be chemotactic rather than chemokinetic in nature. This chemotactic activity was heat stable at 80 degrees C for 30 min, but was abolished at 100 degrees C for 15 min. The chemotactic activity was still maintained after dialysis, but was abolished after incubation with trypsin. It is suggested that the chemotactic factor in M phi-CM may be a protein.

Effects of captopril on platelet cytosolic free Ca2+ concentrations and on suppression of cell proliferation in culture.

In order to investigate the feasibility of angiotensin converting enzyme inhibitors (ACEIs) in preventing the development of atherosclerosis and restenosis after coronary angioplasty and to study their mechanisms, we measured the platelet cytosolic free Ca2+ concentration ([Ca2+]i) and observed the effects of captopril on platelet [Ca2+]i in rabbits and also observed the inhibitive action on fibroblast proliferation in culture. The results showed that resting platelet [Ca2+]i,ADP- or thrombin-stimulated platelet elevation amplitude after administration of captopril (12.5 mg, twice daily) for 15 days were significantly reduced in comparison with those before administration. And captopril also significantly inhibited fibroblast proliferation or reduced 3H-thymidine (3H-TdR) incorporation in culture in a dose-dependent manner. These findings suggest that ACEIs are promising drugs to reduce restenosis incidence after coronary angioplasty and to prevent atherosclerosis as well as provide a new explanation for their effects of suppressing cell proliferation.

["Ghost" bodies and calcification in experimental coronary artery atherosclerosis in pigeons].

Nineteen young pigeons (columba livia domestica) fed on cholesterol (0.5 g per day per bird) for 31 weeks were studied by electron microscopy focusing on calcification in coronary artery atherosclerosis. After 24-31 weeks of cholesterol feeding, smooth muscle cells (SMCs) in the media layer showed an obvious proliferation. Many of these cells had bulbous cytoplasmic pseudopod-like processes connecting with the cell body by narrow stalks. Many of the cytoplasmic pseudopodia as well as the detached cell fragments, i.e. "ghost" bodies measuring 606-2235 nm in diameter were membrane-bounded, but without basement membrane, often with a fibrillo-granular content and occasionally seen as residue of organelles of the SMCs. Additionally, in the interstitial spaces, much vesicle-like deeply osmiophilic material was obtained, suggesting degradation products of SMCs. Furthermore, in the matrix, there were many calcium spherules measuring 551-3006 nm in diameter, consisted of 1-3 layers of radiating crystalline spicules. The mechanism of formation of "ghost" bodies and calcification is discussed.