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FK506 (tacrolimus), a potent immunosuppressive drug primarily used for reduction of allograft rejection in organ transplantation, also offers neuroprotection after central nervous system injury. FK506-mediated immunosuppression and neuroprotection may occur through different mechanisms that could affect neurological recovery and the severity of spinal lesions where cells transplantation therapy is combined with FK506 application. We assessed effects of long-term FK506 administration using the same dose regiment (1 mg/kg/day for 6 weeks) as is used in spinal cord transplantation studies following a balloon-compression induced spinal cord injury (SCI). Body weight and locomotor recovery quantified by the BBB (Basso-Beattie-Bresnehan) locomotor rating scale were evaluated for up to 42 days post-injury. The area of the preserved spinal cord tissue within a 13 mm segment of the spinal cord (lesion epicenter and 6 mm rostral-caudal) was examined histologically. The results showed no significant effects of FK506 on spinal cord tissue sparing or improvement of locomotor recovery. However, body weight fell significantly (P < 0.05) with FK506 treatment when compared with placebo from day 7 until sacrifice. In our experimental design, long-term FK506 treatment did not affect the parameters of outcome following balloon-compression SCI in the rat; however, multiple effects of FK506 should be taken into account when evaluating the outcomes in transplantation studies.

It is well established that strong electromagnetic fields (EMFs) can give rise to acute health effects, such as burns, which can be effectively prevented by respecting exposure guidelines and regulations. Current concerns are instead directed toward the possibility that long-term exposure to weak EMF might have detrimental health effects due to some biological mechanism, to date unknown. (1) The possible risk due to pulsed EMF at frequency 2.45 GHz and mean power density 2.8 mW/cm(2) on rat postnatal neurogenesis was studied in relation to the animal's age, duration of the exposure dose, and post-irradiation survival. (2) Proliferating cells marker, BrdU, was used to map age- and dose-related immunohistochemical changes within the rostral migratory stream (RMS) after whole-body exposure of newborn (P7) and senescent (24 months) rats. (3) Two dose-related exposure patterns were performed to clarify the cumulative effect of EMF: short-term exposure dose, 2 days irradiation (4 h/day), versus long-term exposure dose, 3 days irradiation (8 h/day), both followed by acute (24 h) and chronic (1-4 weeks) post-irradiation survival. (4) We found that the EMF induces significant age- and dose-dependent changes in proliferating cell numbers within the RMS. Our results indicate that the concerns about the possible risk of EMF generated in connection with production, transmission, distribution, and the use of electrical equipment and communication sets are justified at least with regard to early postnatal neurogenesis.

1. The aim of our study was to investigate the possibility that maternal separation, an experimental model for studies of early environmental influences, has an effect on postnatal neurogenesis in neurogenic pathway--the rostral migratory stream (RMS). 2. Rat pups were subjected to maternal separation daily for 3 h, starting from the first postnatal day (P1) till P14 or P21. In the first two groups, brains were analyzed at the age of P14 and P21, respectively. In the third group, after 3 weeks of maternal separation, 1 week of normal rearing was allowed, and the brains were analyzed at P28. The controls matched the age of maternally separated animals. Dividing cells were labeled by bromodeoxyuridine; dying cells were visualized by Fluoro-Jade C and nitric oxide (NO) producing cells by NADPH-diaphorase histochemistry. 3. Quantitative analysis of proliferating cells in the RMS showed that maternal separation decreased the number of dividing cells in all experimental groups. This decrease was most prominent in the caudal part of the RMS. The amount of dying cells was increased at the end of 3 weeks of maternal separation as well as 1 week later. The number of differentiated nitrergic cells in the RMS was increased at the end of 2 or 3 weeks of maternal separation, respectively. Besides quantitative changes, maternally separated animals showed an accelerated maturation of nitrergic cells. 4. Our results indicate that an exposure of rats to adverse environmental factors in early postnatal periods may induce acute site-specific changes in the RMS neurogenesis.

1. The fluorescein derivate Fluoro-Jade B (FJB), which primarily labels dead or dying neurons, was used to study the acute focal inflammation in the spinal cord white matter. Inflammation was induced by microinjection of the yeast particulate zymosan to evaluate the biological effects of intraspinal macrophages activation without the confounding effects of physical trauma. 2. A single bolus of zymosan (Sigma, 75 nL) was stereotaxically injected at the thoracic level into the lateral white matter of rat spinal cord. A standard Fluoro-Jade B staining protocol was applied to spinal cord sections at 6, 12, 24 h and 2, 4 days postinjection. Neutral Red, NADPH-diaphorase, Iba1-IR, and DAPI staining protocols accomplished examination of the cells participating in the acute inflammatory response. 3. Zymosan caused formation of clearly delineated inflammation lesions localized in the lateral white matter of the spinal cord. Fluoro-Jade B stained cells in the area of inflammation were not observed at 12 h postinjection while mild FJB staining appeared at 24 h and intense staining was observed at 2 and 4 days postinjection. 4. This study shows that the acute response to zymosan-induced inflammation in the rat spinal cord white matter causes a gradual appearance of phagocytic microglia/macrophages and delayed FJB staining of the inflammatory cells. 5. FJB, a reliable marker of dying neurons, is a more universal agent than formerly believed. One possible explanation for the gradual appearance of FJB-stained cells in the area of inflammation is that specific time is required for sufficient levels of proteins and/or myelin debris of axonal origin to appear in the cytoplasm of phagocytic microglia/macrophages.

The objective of this study was to analyze neurogenesis in the rat rostral migratory stream (RMS) during the first postnatal month. 1. During the early postnatal development some morphological changes, concerning the RMS thickness, shape, and the olfactory ventricle persistence at P0 were observed. 2. Bromodeoxyuridine (BrdU) immunohistochemistry and subsequent quantification of proliferating cells showed significant age-dependent changes. The highest number of proliferating cells was found at P3 and significant decrease of BrdU-positive cells at P7 rats. At P28, the number of proliferating cells reached the level of P0 rats.

A novel fluorochrome, Fluoro-Jade B, was used to detect dying precursor cells in the subventricular zone (SVZ) and rostral migratory stream (RMS) of adult rats after bilateral olfactory bulbectomy and in control intact rats. The animals in experimental group were left to survive 3 days and from 3 till 16 months after surgical procedure. 1. In the control animals, Fluoro-Jade B positive cells were visible in the SVZ and within the whole extent of the RMS. The number of Fluoro-Jade B positive cells increased in the elbow in comparison to the rest parts of the RMS. 2. In the experimental animals surviving either 3 days or from 3 till 16 months after bilateral olfactory bulbectomy, Fluoro-Jade B positive cells displayed the similar pattern of distribution as in the control animals. However, some quantitative differences in the labeled cells number along the rostral migratory pathway appeared. 3. The average number of degenerating cells within the control SVZ and RMS was 26.24+/- 0.686. In bulbectomized animals, regardless of survival time, an insignificant increase of Fluoro-Jade B positive cells number occurred. We can conclude that dying of precursor cells is a physiological process running within the SVZ/RMS in both control and experimental animals. Moreover, this physiological process is not influenced by survival period after bilateral olfactory bulbectomy. Our results demonstrate Fluoro-Jade B as a useful marker of dying cells.

Accumulating evidence confirms that nitric oxide (NO), a versatile diffusible signaling molecule, contributes to controling of adult neurogenesis. We have previously shown the timing of NADPH-diaphorase (NADPH-d) positivity within the rat rostral migratory stream (RMS) during the first postnatal month. The present study was designed to describe further age-related changes of NO presence in this neurogenic region. The presence of NO synthesizing cells in the RMS was shown by NADPH-d histochemistry and neuronal nitric oxide synthase (nNOS) immunohistochemistry. The phenotypic identity of nitrergic cells was examined by double labeling with GFAP and NeuN. Systematic qualitative and quantitative analysis of NADPH-d-positive cells was performed in the neonatal (P14), adult(5 months) and aging (20 months) rat RMS. 1. Nitrergic cells with different distribution pattern and morphological characteristics were present in the RMS at all ages examined. In neonatal animals, small, moderately stained NADPH-d-positive cells were identified in the RMS vertical arm and in the RMS elbow. In adult and aging rats a few labeled cells could be also detected in the RMS horizontal arm. NADPH-d-positive cells in adult and aging rats were characterized by long varicose processes and displayed dark labeling in comparison to the neonatal group. 2. Double immunolabeling has revealed that nNOS-immunoreactivity co-localized with that of NeuN. This indicates that nitrergic cells within the RMS are neurons. 3. Quantitative analysis showed that the number of NADPH-d-positive cells increases with advancing age. The presence of NO producing cells in the RMS of neonatal adult and aging rats indicates, that this proliferating and migratory area is under the influence of NO throughout the entire life of the animals.

The magnetic susceptibility and magnetization of the powder sample of layered polymeric compound CuCl2(bipy), where bipy=C10H8N2, has been studied in the temperature range from 2 K to 300 K and in magnetic fields up to 5 T. The presence of antiferromagnetic exchange interaction is observed. The magnetic dimensionality of the system and the origin of the long-range order indicated below 7 K is discussed.

Magnetostructural correlations have been studied in the title compound at low temperatures. The investigations included the detailed study of hydrogen bond geometry, completed by thermodynamic measurements and electron paramagnetic resonance experiment. In contrast to the expectation based on structural consideration, the investigations revealed surprisingly weak magnetic correlations which can be ascribed to the non-trivial magnetochemistry of the hydrogen bonds present in the structure.

In this paper the physical and technical aspects of experimental study of thermal conductivity of solids at low temperatures are described. The experimental setup for thermal conductivity measurements using steady-state method from 1.5 K to nominally 40 K has been designed and successfully tested. The results of thermal conductivity of molybdenum, studied as reference material, are presented and the origin of difference with the data from literature is discussed.

1. To test our hypothesis that a transient nonlethal ischemic insult benefits the lumbosacral spinal cord ischemic injury, nestin, the marker of proliferating cells, and Fluoro-Jade B, the marker of degenerating cells, were used in rats. Morphological outcome was evaluated after 12-min ischemia versus 12-min ischemia preconditioned by 3-min ischemic period and 30-min recirculation (IPC), in each group followed by 2, 3, and 4 days of posttreatment survival. 2. Twelve-minute ischemia, inducing nestin-positivity in ependyma and reactive astrocytes at the L(1-3) spinal cord segments, shows this region as the viable region of spinal cord in all postischemic survival periods. On the other hand, abundance of Fluoro-Jade B-positive cells, distributed throughout the dorsal horn and intermediate zone of L4-S2 segments, points out the most injured spinal cord region by ischemia. 3. After the same ischemic insult in IPC rats only a few nestin-positive ependymal cell and reactive astrocytes appeared beside the nestin-positive vessels in the lower lumbar and sacral spinal cord segments of all survival periods. The appearance of nestin-positive cells in the spinal cord segments, which "should have been affected" by ischemia indicates protection of this region by the IPC treatment. 4. The number and density evaluation of Fluoro-Jade B fluorescent cells of L4-S2 segments after ischemia and IPC confirmed that degenerating cells were significantly reduced in the IPC rats in all survival periods. 5. Our results showing the immunohistochemical response of epemdyma, committed to the presence of viable tissue, indicate that the ependymal cells may contribute to the ischemic resistance in the IPC rats.

Previous studies have shown that spinal L-type, N-type, and P-type Ca2+-channel blockers are effective in modulating pain behavior caused nerve injury. In the present work, using the loose ligation of the sciatic nerve model, we characterized the time course of the appearance of tactile and cold allodynia and the corresponding spinal expression of the N-type Ca2+ channel alpha(1B)-subunit after nerve ligation. Within 1 week after ligation, the majority of rats developed a unilateral sensitivity to mechanical stimulation (von Frey filaments), as well as sensitivity to cold, which persisted for 30 days. Immunocytochemical analysis of the spinal cord in sham-operated animals for the alpha(1B)-subunit showed a smooth, moderate staining pattern in the superficial laminae I-II, as well as in ventral alpha-motoneurons. In nerve-ligated animals, an intense, dot-like immunoreactivity in the ipsilateral dorsal horn was observed from 5-20 days after nerve ligation. The most prominent alpha(1B)-subunit upregulation was found in the outer as well as the inner part of lamina II (II(o), II(i)), extending from the medial toward the lateral region of the L4 and L5 spinal segments. The behavioral changes which developed after chronic constriction injury directly correlated with the alpha(1B)-subunit upregulation in the corresponding spinal cord segments. These data suggest that upregulation of the spinal alpha(1B)-subunit may play an important role in the initiation and maintenance of pain state after peripheral nerve injury.

In this paper we present theoretical studies of Ising dipolar system in the paramagnetic regime. Mean-field approximation with the nearest-neighbour interaction involved in one direction has been applied. The corresponding theoretical predictions of specific heat are compared with experimental specific heat data of the title compound. The influence of further interactions is discussed.

The paper overviews the behaviour of dipolar magnets with tetragonal lattice characterized by the ratio r = c/a reflecting the measure of tetragonal distortion of the crystal structure. It is shown that in zero magnetic field the dipolar systems with sufficiently large r despite the long-range character of the magnetic correlations can be mapped to two-dimensional Ising model with the nearest-neighbour interaction only. The magnetic properties of dipolar magnets with r ≥ 2 are described by reviewing the results obtained primarily on rare earth (R) dipolar magnets from the RBa2Cu3O7-δ and AR(MoO4)2 series (A = Cs,K).

The specific heat of [CuII(en)2(H2O)][CuII(en)2Ni2Cu2I(CN)10]·2H2O was measured in the temperature range from 1.5 K to 10 K. The studies did not reveal any phase transition into an ordered state. Magnetization measurements, at 4.2 K and 13.7 K and in fields up to 60 kG, confirmed the assumption of weak exchange interactions, resulting from the knowledge of the crystal structure. Magnetic susceptibility data show deviations from Curie-Weiss law near 5.5 K. The analysis of the inverse susceptibility data indicates the presence of antiferromagnetic exchange coupling J/kB≈−0.65 K.

1. The aim of the present study is to map the incipient phase of Fos expression in the sacral spinal cord neuronal pools of multiple cauda equina constrictions canine model. 2. Fos-positive neurons were found bilaterally in the lateral portion of superficial dorsal horn layers (Laminae I–III) and along the lateral edge of the dorsal horn accompanied by the lateral collateral pathway, fibers of Lissauer's tract, terminating at the sacral parasympathetic nucleus. Similarly, high Fos expression was detected in the ventral portion of the dorsal sacral commissure and in the dorsomedial portion of the anterior horns at S1–S3 segment level. Finally, a clearly expressed Fos-positivity was disclosed bilaterally in the neuropil of the nucleus Y in the anterior horn. 3. Data from the present study show that continuous stimulation of the central fibers of sacral dorsal root ganglia neurons, i.e., fibers of sacral primary afferents, unlike those using various stimulations of the peripheral fibres offers an unusual pattern of Fos-like immunoreactivity.

1. In the present study, we characterize the time course of spinal FOS protein expression after transient noninjurious (6-min) or injurious (12-min) spinal ischemia induced by inflation of a balloon catheter placed into the descending thoracic aorta. In addition, this work examined the effects of spinal hypothermia on FOS expression induced either by ischemia or by potassium-evoked depolarization (intrathecal KCl). 2. Short-lasting (6-min) spinal ischemia evoked a transient FOS protein expression. The peak expression was seen 2 hr after reperfusion in all laminar levels in lumbosacral segments. At 4 hr of reperfusion, more selective FOS expression in spinal interneurons localized in the central part of laminae V-VII was seen. At 24 hr no significant increase in FOS protein was detected. 3. After 12 min of ischemia and 2 hr of reflow, nonspecific FOS expression was seen in both white and gray matter, predominantly in nonneuronal elements. Intrathecal KCl-induced FOS expression in spinal neurons in the dorsal horn and in the intermediate zone. Spinal hypothermia (27 degrees C) significantly suppressed FOS expression after 6 or 12 min of ischemia but not after KCl-evoked depolarization. 4. Data from the present study show that an injurious (but not noninjurious) interval of spinal ischemia evokes spinal FOS protein expression in glial cells 2 hr after reflow. The lack of neuronal FOS expression corresponds with extensive neuronal degeneration seen in this region 24 hr after reflow. Noninjurious (6-min) ischemia induced a transient, but typically neuronal FOS expression. The significant blocking effect of hypothermia (27 degrees C) on the FOS induction after ischemia but not after potassium-evoked depolarization also suggests that simple neuronal depolarization is a key trigger in FOS induction.

Our previous experimental study has identified Ni(C2H8N2)2Ni(CN)4 (NENC) as an S=1 antiferromagnetic (AF) Heisenberg chain with strong planar anisotropy D/kB≈6 K and D/|J|≈7.5. The position of the system in the (D,λ) phase diagram ((7.5,1) in units J) has enabled the study of excitons as elementary excitations from the singlet ground state (SGS). Strong coupling theory for the thermodynamics of 1d S=1 large—D systems is used for the re—analysis of specific heat and susceptibility data. The influence of in—plane anisotropy and exciton interactions is discussed.