Remarkable progress in the physical parameters of net-current free plasmas has been made in the Large Helical Device (LHD) since the last Fusion Energy Conference in Chengdu, 2006 (O.Motojima et al., Nucl. Fusion 47 (2007. The beta value reached 5 % and a high beta state beyond 4.5% from the diamagnetic measurement has been maintained for longer than 100 times the energy confinement time. The density and temperature regimes also have been extended. The central density has exceeded 1.0×10 21 m -3 due to the formation of an Internal Diffusion Barrier (IDB). The ion temperature has reached 6.8 keV at the density of 2×10 19 m -3 , which is associated with the suppression of ion heat conduction loss. Although these parameters have been obtained in separated discharges, each fusion-reactor relevant parameter has elucidated the potential of net-current free heliotron plasmas. Diversified studies in recent LHD experiments are reviewed in this paper.

The requirement of complex sphingolipid biosynthesis for growth of neurons was examined in developing rat cerebellar Purkinje neurons using a dissociated culture system. Purkinje cells developed well‐differentiated dendrites and axons after 2 weeks in a serum‐free nutrient condition. Addition of 2 µM fumonisin B1, a fungal inhibitor of mammalian ceramide synthase, inhibited incorporation of [3H]galactose/glucosamine and [14C]serine into complex sphingolipids of cultured cerebellar neurons. Under this condition, the expression of Purkinje cell‐enriched sphingolipids, including GD1α, 9‐O‐acetylated LD1 and GD3, and sphingomyelin, was significantly decreased. After 2 weeks' exposure to fumonisin B1, dose‐dependent measurable decreases in the survival and visually discernible differences in the morphology were seen in fumonisin‐treated Purkinje cells. The Purkinje cell dendrites exhibited two types of anomalies; one population of cells developed elongated but less‐branched dendrites after a slight time lag, but their branches began to degenerate. In some cells, formation of elongated dendrite trees was severely impaired. However, treatment with fumonisin B1 also led to the formation of spinelike protrusions on the dendrites of Purkinje cells as in control cultures. In contrast to the alterations observed in Purkinje cells, morphology of other cell types including granule neurons appeared to be almost normal after treatment with fumonisin B1. These observations indicated strongly that membrane sphingolipids participate in growth and maintenance of dendrites and in the survival of cerebellar Purkinje cells. Indeed, these effects of fumonisin B1 were reversed, but not completely, by the addition of 6‐[[N‐(7‐nitrobenz‐2‐oxa‐1,3‐diazol‐4‐yl)‐amino]caproyl]sphingosine (C6‐NBD‐ceramide), a synthetic derivative of ceramide. Thus, we conclude that deprivation of membrane sphingolipids in a culture environment is responsible for aberrant growth of Purkinje cells.

To examine whether motor commands of two or more distinct laryngeal motor patterns converge onto a common premotor network, we conducted dual recordings from the laryngeal adductor motoneuron and its premotor neuron within the brainstem respiratory circuitry during fictive breathing, coughing, sneezing, and swallowing in decerebrate paralyzed cats. Expiratory neurons with an augmenting firing pattern (EAUG), whose action potentials evoked monosynaptic IPSPs in the adductor motoneurons, sharply fired during the expulsive phases of fictive coughing and sneezing, during which the adductor motoneurons transiently repolarized. In contrast, these premotor neurons were silent during the swallow-related hyperpolarization in adductor motoneurons. These results show that one class of medullary respiratory neuron, EAUG, is multifunctional and shared among the central pattern generators (CPGs) for breathing, coughing, and sneezing. In addition, although the CPGs underlying these three behaviors and the swallowing CPG do overlap, EAUG neurons are not part of the swallowing CPG and, in contrast to the other three behaviors, are not a source of inhibitory input to adductor motoneurons during swallowing.

Phospholipase A activity was demonstrated in guinea pig spermatozoa using [U-'"C] phosphatidyl choline as a substrate. The activity had a neutral pH optimum, was stimulated by Ca2+ and low concentrations of detergent, and. was inhibited by EDTA, mepacrine and p-bromophenacyl bromide. Appropriate concentrations of 'mepacrine and p-bromophenacyl bromide inhibited the acrosome reactions of capacitated spermatozoa without interfering with their motility. These results support the notion that phospholipase A is involved in the acrosome reaction of mammalian spermatozoa.Mammalian spermatozoa must undergo the acrosome reaction before effecting fertilization. The reaction involves multiple fusions between the outer acrosomal and the overlying plasma membranes (I), which allow the release of acrosomal enzymes and the exposure of the inner acrosomal membrane. If the acrosome reaction does not occur, spermatozoa are unable to pentrate the egg investments (particularly the zona pellucida) and to fuse with the egg plasma membrane (24). The molecular mechanisms of the acrosome reaction are not fully understood, but it is evident that the reaction involves a complicated series of chemical reactions in the acrosomal complex including the plasma membrane (4-6).Recently, LUI and MEIZEL (7) and FLEMING and YANAGIMACHI (8) presented circumstantial evidence that phospholipase might be involved in the acrosome reactions of hamster and guinea pig spermatozoa. According to LLANOS et al. (9), materials released from hamster spermatozoa during acrosome reaction have phospholipase activities. This could be taken as supportive evidence that phospholipase in the acrosomal region of the spermatozoon is indeed involved in the acrosome reaction. This paper reports that guinea pig spermatozoa have phospholipase activity and the enzyme is very likely involved in the acrosome reaction in this species.

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