Expression of serotonin2A receptors in Purkinje cells of the developing rat cerebellum

Previous physiological and pharmacological studies have shown that the serotonin_2A (5-HT_2A) receptor is involved in cerebellar functions. However, the expression of 5-HT_2A receptors in the developing cerebellum has not been elucidated to date. In the present immunohistochemical study, we examined developmental changes of the distribution of 5-HT_2A receptors in Purkinje cells of the rat cerebellum from embryonic day 18 (E18) to postnatal day 21 (P21). The weak immunoreaction to 5-HT_2A receptors was found in the deep cerebellar nuclei on E19. In the cerebellar cortex of the hemisphere and the posterior vermis, somata of Purkinje cells became weakly immunoreactive on P0. With the dendritic elongation and arborization, the immunoreaction appeared in the proximal parts of Purkinje cell dendrites. Distal parts of the dendrites became immunoreactive after P12, and were strongly immunolabeled by P21. The present study may provide a structural basis to investigate the roles of 5-HT_2A receptors during the cerebellar development.     

Three novel mutations of the fibrillin-1 gene and ten single nucleotide polymorphisms of the fibrillin-3 gene in Marfan syndrome patients

Marfan syndrome (MFS) is an autosomal dominant disorder of the extracellular matrix. Allelic variations in the gene for fibrillin-1 (FBN1) have been shown to cause MFS. To date, over 550 mutations have been identified in patients with MFS and related connective tissue diseases. However, about a half of MFS cases do not possess mutations in the FBN1 gene. These findings raise the possibility that variants located in other genes cause or modify MFS. To explore this possibility, firstly we analyzed FBN1 allelic variants in 12 Japanese patients with MFS, and secondly we analyzed fibrillin-3 gene (FBN3) in patients without FBN1 mutations using conformation sensitive gel electrophoresis (CSGE) and direct sequencing analysis. We identified three novel FBN1 mutations and ten FBN3 single nucleotide polymorphisms (SNPs). In this report, we could not detect a responsible mutation of the FBN3 gene for MFS. Although the number of the cases in this report is small, at least these results suggest that disease-causing mutations in exon regions of the FBN3 gene are very rare in MFS.Nucleotide sequence data reported are available in the DDBJ/EMBL/GenBank databases under the accession numbers: AB177797, AB177798, AB177799, AB177800, AB177801, AB177802, AB177803     

Effects of running exercise during recovery from hindlimb unloading on soleus muscle fibers and their spinal motoneurons in rats

The effects of hindlimb unloading and recovery with or without running exercise on morphological and metabolic properties of soleus muscle fibers and their spinal motoneurons in rats were investigated. Ten-week-old rats were hindlimb suspended for 2 weeks and thereafter were rehabilitated with or without voluntary running exercise for 2 weeks. A decreased percentage of type I fibers and atrophy of all types of fibers were observed after hindlimb unloading. In addition, decreased oxidative enzyme activity of all types of fibers was observed after hindlimb unloading. In contrast, an improvement in the decreased percentage of type I fibers, decreased fiber cross-sectional area, and decreased fiber oxidative enzyme activity was observed after recovery with running exercise, but not without running exercise. There were no changes in the number, cell body size, or oxidative enzyme activity of motoneurons innervating the soleus muscle after hindlimb unloading or recovery with or without running exercise. These results indicate that running exercise is beneficial for the recovery of the decreased percentage of type I fibers and the atrophy and decreased oxidative enzyme activity of all types of fibers in the soleus muscle induced by hindlimb unloading and that there are no changes in morphological or metabolic properties of spinal motoneurons innervating the soleus muscle following decreased or increased neuromuscular activity.     

Neuronal protein NP25 interacts with F-actin

Neuronal protein NP25 is a neuron-specific protein present in highly differentiated neural cells, but its functional properties have not been well characterized. NP25 shows high amino acid sequence homology with the smooth muscle cell cytoskeleton-associated proteins, SM22, mp20, and calponin. To gain an insight into the biological functions of NP25, we first examined its subcellular localization in the human neuroblastoma cell line, SK-N-SH. NP25 diffusely distributed in the cytoplasm and fiber-like staining was also observed. It showed that NP25 co-localized with F-actin on stress fibers. A co-sedimentation assay demonstrated that NP25 bound to filamentous actin. Further investigations using fluorescence resonance energy transfer (FRET) technique revealed intracellular binding of NP25 and actin. The significance of the interaction between NP25 and F-actin is discussed.     

Adaptive Predictive Control of Arterial Blood Pressure Based on a Neural Network During Acute Hypotension

In acute hypotension, an automated drug infusion system to control mean arterial blood pressure (MAP) has not been previously studied, though many investigations have examined the use of vasodilating drugs to control MAP in postoperative hypertension. Therefore, we examined an automated control of MAP during acute hypotension using a neural network (NN) approach. A proportional-integral-derivative (PID) control, an adaptive predictive control using a NN (APC(NN)), a combined control of APC(NN) and PID (APC(NN-PID)), a fuzzy control, and a model predictive control were tested in computer simulation based on the MAP response to norepinephrine (NE) of 25 microg ml(-1). In six anesthetized rabbits, using the NE of 25 microg ml(-1), the PID control, APC(NN), and APC(NN-PID) prevented severe hypotension compared to an uncontrolled condition. Under PID control, four of the six animals showed MAP oscillation. Using NE of 50 microg ml(-1), the rabbits recovered from acute hypotension for all systems tested but showed sustained MAP oscillation during PID control. In conclusion, utilization of a NN for adaptive predictive control systems could facilitate the development of an automated drug infusion apparatus because it provides robust control even when acute or large perturbations and inter-individual differences in the sensitivity to therapeutic agents occur.     

Prion domain interaction responsible for species discrimination in yeast [PSI+] transmission

BACKGROUND: The yeast [PSI+] factor is transmitted by a prion mechanism involving self-propagating Sup35 aggregates. As with mammalian prions, a species barrier prevents prion transmission between yeast species. The N-terminal of Sup35 of Saccharomyces cerevisiae, necessary for [PSI+], contains two species-signature elements-a Gln/Asn-rich region (residues 1-41; designated NQ) that is followed by oligopeptide repeats (designated NR). RESULTS: In this study, we show that S. cerevisiae[PSI+] is transmissible through plasmid shuffling and cytoplasmic transfer to heterotypic Sup35s whose NQ is replaced with the S. cerevisiae NQ. In addition to homology, the N-terminal location is essential for NQ mediated susceptibility to [PSI+] transmission amongst heterotypic Sup35s. In vitro, a swap of NQ of S. cerevisiae Sup35 led to cross seeding of amyloid formation. CONCLUSIONS: These findings suggest that NQ discriminates self from non-self, and is sufficient to initiate [PSI+] transmission irrespective of whether NR is heterotypic. NR as well as NQ alone coalesces into existing [PSI+] aggregates, showing their independent potentials to interact with the identical sequence in the [PSI+] conformer. The role of NQ and NR in [PSI+] prion formation is discussed.     

Clinicopathologic differences between 22 cases of CD56-negative and CD56-positive subcutaneous panniculitis-like lymphoma in Japan

CD56 is an important marker for prospecting clinicopathologic features of cytotoxic T-cell and natural killer (NK)/T-cell lymphomas. We examined 22 cases of subcutaneous panniculitis-like lymphoma and classified these into CD56-positive and CD56-negative groups. The 11 CD56-negative cases were mainly in the younger age group and had systemic subcutaneous nodules without ulceration. They exhibited subcutaneous invasion by medium-sized lymphoma cells, scattered erythrophagocytosis, patchy necrosis, and little tumor invasion in the superficial dermis. Their lymphoma cells had characteristics of CD3 epsilon-, CD8-, TcR beta F1-, T-cell intracellular antigen (TIA)1-, and granenzyme B-positive cytotoxic T cells and were negative for apoptosis-promoting proteins CD95 (Fas), Bax, CPP32 (caspase 3), and p53 (DO7). Ten patients were alive despite clinical signs of hemophagocytic syndrome and relapses in 7 cases. The 11 CD56-positive cases had systemic ulcerative skin tumors composed of pleomorphic lymphoma cells with massive necrosis and little erythrophagocytosis involving the subcutis and also often the whole dermis. Their tumor cells were positive for CD3 epsilon, TIA1, granenzyme B, CD95, CD95L (Fas ligand), Bax, and CPP32. Three cases were of the TcR beta F1-positive phenotype, 1 was of the TcR gamma/delta-positive T-cell phenotype, and 6 were of the TcR beta F1- and TcR gamma/delta-negative NK/T-cell phenotype. Six cases were p53 (DO7) positive. Seven cases had complications of liver dysfunction and cytopenia, and 8 died of disease. One CD56-negative case and 3 CD56-positive cases had nuclear signals of Epstein-Barr virus-encoded RNA in their lymphoma cells. The 2 groups had significantly (P <0.01) different prognoses by Kaplan-Meier and log-rank methods. Patients with CD56-negative and CD56-positive groups had statistically different clinicopathologic, immunohistologic, and functional findings and prognoses.     

Existence of a small population of IL-2Rβhi TCRint cells in SCG and MRL-lpr/lpr mice which produce normal Fas mRNA and Fas molecules from the lpr gene

Mice carrying the lpr gene, SCG and MRL-lpr/lpr mice, were used to characterize the phenotype and lpr gene of abnormally proliferating T cells in these mice. A major population which expanded in these mice were T cells expressing intermediate (int) levels of T cell receptor (TCR) (and CD3) and the phenotype of interleukin-2 receptor (IL-2R)β^lo α^? (possibly abnormal TCR^int cells). The levels of TCR^hi cells of thymic origin (generated through the mainstream of T cell differentiation in the thymus) profoundly decreased after the onset of disease. However, a small population of normal TCR^int cells (i.e. IL-2Rβ^hi α^?) were also found to exist in all tested organs. For example, the majority of abnormal IL-2Rβ^lo TCR^int cells were CD4^?8^? CD2^?, while normal IL-2Rβ^hi TCR^int cells were a mixture of single-positive cells (mainly CD8⁺), CD4^?8^? cells and CD2⁺ cells. Moreover, normal TCR^int cells preferentially produced normal Fas mRNA and Fas molecules from the lpr gene. This phenomenon explains the leaky appearance of normal Fas mRNA and Fas molecules in mice carrying the lpr gene. It is suggested that a small population of IL-2Rβ^hiTCR^int cells are resistant to the lpr genetic abnormality.