Activity during active sleep of bulbar reticular neurons firing rhythmically during mastication in cats

Unitary activity was recorded from 17 bulbar reticular neurons, which fired rhythmically during mastication, in unanesthetized, spontaneously respiring cats during sleep and wakefulness. All these neurons showed the highest mean firing rate during food ingestion, and none of them showed any tonic discharge during active sleep. The results are discussed in terms of a functional differentiation of bulbar reticular inhibitory neurons projecting to jaw-closer motoneurons in relation to phasic inhibition during mastication and tonic inhibition during active sleep of jaw-closer motoneurons.     

Etodolac induces apoptosis and inhibits cell adhesion to bone marrow stromal cells in human myeloma cells

OBJECTIVES: Cyclooxygenase-2 (COX-2) is reported to regulate apoptosis and to be an important cellular target for therapy. METHODS: We examined whether etodolac, meloxicam, and thalidomide inhibited proliferation and induced apoptosis in myeloma cell lines (RPMI 8226 and MC/CAR cells). RESULTS: Etodolac induced apoptosis more strongly compared with thalidomide or meloxicam. Etodolac induced down-regulation of Bcl-2 protein and mRNA, activation of Caspase-9, -7 and -3, cIAP-1 and Survivin, and loss of mitochondrial membrane potential in a dose-dependent manner. In addition, when myeloma cells were coincubated with 50 microM etodolac on bone marrow stromal cells (BMSCs), myeloma cell adhesion to BMSCs was significantly inhibited compared with thalidomide or meloxicam coincubation, and the adhesion molecules VLA-4, LFA-1 (CD11a), CXCX4, and CD44 were suppressed on myeloma cells treated with etodolac. Moreover, 50-100 microM racemate of etodolac significantly inhibited the proliferation of myeloma cells compared to 100 microM R-etodolac or S-etodolac. CONCLUSIONS: Etodolac induced loss of mitochondrial membrane potential and apoptosis via a COX-2-independent pathway, suppressed the expression of adhesion molecules, and inhibited myeloma cell adhesion to BMSCs compared with thalidomide or meloxicam. The activities of etodolac potentially extend to the treatment of patients with myeloma resistant to standard chemotherapy, including thalidomide.     

Polarized osteoclasts put marks of tartrate-resistant acid phosphatase on dentin slices--a simple method for identifying polarized osteoclasts

Osteoclasts form ruffled borders and sealing zones toward bone surfaces to resorb bone. Sealing zones are defined as ringed structures of F-actin dots (actin rings). Polarized osteoclasts secrete protons to bone surfaces via vacuolar proton ATPase through ruffled borders. Catabolic enzymes such as tartrate-resistant acid phosphatase (TRAP) and cathepsin K are also secreted to bone surfaces. Here we show a simple method of identifying functional vestiges of polarized osteoclasts. Osteoclasts obtained from cocultures of mouse osteoblasts and bone marrow cells were cultured for 48 h on dentin slices. Cultures were then fixed and stained for TRAP to identify osteoclasts on the slices. Cells were removed from the slices with cotton swabs, and the slices subjected to TRAP and Mayer's hematoxylin staining. Small TRAP-positive spots (TRAP-marks) were detected in the resorption pits stained with Mayer's hematoxylin. Pitted areas were not always located in the places of osteoclasts, but osteoclasts existed on all TRAP-marks. A time course experiment showed that the number of TRAP-marks was maintained, while the number of resorption pits increased with the culture period. The position of actin rings formed in osteoclasts corresponded to that of TRAP-marks on dentin slices. Immunostaining of dentin slices showed that both cathepsin K and vacuolar proton ATPase were colocalized with the TRAP-marks. Treatment of osteoclast cultures with alendronate, a bisphosphonate, suppressed the formation of TRAP-marks and resorption pits without affecting the cell viability. Calcitonin induced the disappearance of both actin rings and TRAP-marks in osteoclast cultures. These results suggest that TRAP-marks are vestiges of proteins secreted by polarized osteoclasts.     

Immunoelectron microscopic and biochemical studies of caspase-cleaved tau in a mouse model of tauopathy

Neurofibrillary tangles (NFTs) have been implicated in mediating neuronal death and disease progression in human tauopathies; however, mounting in vivo data suggest that NFTs may not be the primary initiators of neurotoxicity. Caspase activity has been implicated in processes associated with the development of tauopathy, but the position that caspase activation holds in neurodegenerative cascades remains uncertain. Using multiphoton real-time imaging microscopy, de Calignon et al recently demonstrated that caspase activation precedes and leads to tangle formation within 24 hours in the rTg4510 mouse model of tauopathy. Here, we used immunoelectron microscopy to determine whether caspase-cleaved tau was present in NFTs of rTg4510 mice. Using a caspase-cleaved tau-specific antibody (TauC3), we found very little immunogold labeling in NFTs in the brains of rTg4510 mice. By immunohistochemistry, the number of TauC3-positive neurons was far less than the numbers of neurons stained with the MC1 antibody, which recognizes abnormal conformations of tau. Biochemically, caspase-cleaved tau was barely detectable in fractions of rTg4510 mouse brain extracts. Our data suggest that caspase activation might be one of multiple routes through which NFT formation occurs, rather than an obligatory initiation step in pathologic tau production in rTg4510 mice.     

Ruptured high flow gastric varices with an intratumoral arterioportal shunt treated with balloon-occluded retrograde transvenous obliteration during temporary balloon occlusion of a hepatic artery

INTRODUCTIONHematemesis of ruptured high ? ow gastric varices from intratumoral arterioportal shunt is a critical condition. The transjugular intrahepatic portosystemic shunt (TIPS)[1-2] and percutaneous transhepatic obliteration (PTO) are contraindicatio…     

Role for interleukin-6 and insulin-like growth factor-I via PI3-K/Akt pathway in the proliferation of CD56- and CD56+ multiple myeloma cells

OBJECTIVES: Several studies including ours have suggested that lack of CD56 in multiple myeloma (MM) defines a unique patient subset with poorer prognosis. However, the mechanism underlying this aggressive behavior of CD56(-) MM has not been well elucidated. Interleukin-6 (IL-6) or insulin-like growth factor I (IGF-I) induce proliferation of MM cells. In this study, we report about the relationship between CD56 expression and responsiveness to these cytokines. METHODS: We sorted out both CD56(-) and CD56(+) fractions from MM cell lines such as KMS-21-BM and U-266, and investigated their different responsiveness to IL-6 or IGF-I. Furthermore, we compared the effects of these cytokines on the regulation of cell-cycle distribution between CD56(-) and CD56(+) cells. RESULTS: Although CD56(-) cells in both KMS-21-BM and U-266 cells responded significantly to IL-6, CD56(+) cells did not. Ki-67(+) cells in the CD56(-) cells were significantly increased by IL-6. Western blotting showed that IL-6 phosphorylated Akt, and upregulated and downregulated the level of cyclin D1 and p27 protein in the CD56(-) KMS-21-BM cells, respectively. LY-294002 completely blocked these effects of IL-6. On the other hand, Ki-67(+) cells in the CD56(+) cells did not respond to IL-6. Anti-IGF-I mAb significantly reduced Ki-67(+) cells only in the CD56(+) cells. IGF-I phosphorylated Akt and upregulated cyclin D1 in the CD56(+) KMS-21-BM cells, which was completely blocked by LY294002. CONCLUSIONS: These results suggest that CD56(-) and CD56(+) MM cells could be stimulated by IL-6 and IGF-I, respectively, via PI3-K/Akt pathway, and provide useful information for anticytokine therapies.     

New Insights in the Treatment Strategy for Pulmonary Arterial Hypertension

Introduction Recent advances in our understanding of the pathophysiological and molecular mechanisms involved in pulmonary arterial hypertension have led to the development of novel and rational pharmacological therapies. In addition to conventional therapy (i.e., supplemental oxygen and calcium channel blockers), prostacyclin or endothelin receptor antagonists have been recommended as a first-line therapy for pulmonary arterial hypertension. However, these treatments have potential limitations with regard to their long-term efficacy and improvement in survival. Furthermore, intravenous prostacyclin (epoprostenol) therapy, which is recommended by most experts for patients with New York Heart Association (NYHA) functional class IV, is complicated, uncomfortable for patients, and expensive because of the cumbersome administration system. Considering these circumstances, it is necessary to develop additional novel therapeutic approaches that target the various components of this multifactorial disease. Case report In this short review, we present an overview of the current treatment options for pulmonary arterial hypertension and describe a case report with primary pulmonary hypertension. A male patient with NYHA functional class IV and showing no response to calcium channel blockers and prostacyclin exhibited significantly improved exercise tolerance and hemodynamics and long-term survival for more than 2.5 years after receiving an oral combination therapy of a phosphodiesterase type 5 inhibitor (sildenafil), phosphodiesterase type 3 inhibitor (pimobendan), and nicorandil. Future perspective We also discuss the background and plausible potential mechanisms involved in this case, as well as future perspectives in the treatment of pulmonary arterial hypertension.     

Low-voltage-activated potassium channels underlie the regulation of intrinsic firing properties of rat vestibular ganglion cells

Individual primary vestibular afferents exhibit spontaneous activity the regularity of which can vary from regular to irregular. Different aspects of vestibular responsiveness have been associated with this dimension of regularity of resting discharge. Isolated rat vestibular ganglion cells (VGCs) showed heterogeneous intrinsic firing properties during sustained membrane depolarization: some neurons exhibited a strong adaptation generating just a single or a few spikes (phasic type), whereas other neurons showed moderate adaptation or tonic firing (tonic type). Tonic discharging VGCs were rare at postnatal days 5–7 and increased up to 60% of neurons during postnatal 2–3 wk. To explore the major factors responsible for the discharge regularity of primary vestibular afferents, we investigated the contribution of K⁺ channels to the firing properties of isolated rat VGCs. Phasic firing became tonic firing in the presence of 4-aminopyridine or -dendrotoxin, indicating that Kv1 potassium channels control the firing pattern of the phasic VGCs. Tetraethylammonium decreased the number of spikes during step current stimuli in all types. Blockade of Ca²⁺-activated K⁺ channels decreased the number of spikes in tonic VGCs. Our results suggest that Kv1 channels are critical both in determining the pattern of spike discharge in rat vestibular ganglion neurons and in their proportional change during maturation.