Lysophospholipids improve skin moisturization by modulating of calcium-dependent cell differentiation pathway.

Recent studies have demonstrated that lysophospholipids (LPL) play critical roles in several biological signal transduction pathways to maintain the homoeostasis of cells, tissues and organs. Among them, lysophosphatidic acid (LPA) has been identified as a lipid mediator that induces morphological improvement in the epidermis in mice. In this study, we examined the effects of LPL (soybean-derived phospholipids modified with phospholipase A2 and C) compared with LPA. We initially examined the effects of LPA on normal human epidermal keratinocytes (NHEK) focusing on the expression of profilaggrin and serine palmitoyltransferase (SPT) mRNAs. LPA enhanced the expression of profilaggrin and SPT mRNAs via the modulation of Ca(2+) influx. Based on those results, the influence of LPL on NHEK was examined and was expanded to analyse the expression of two tight junction-related proteins, occludin and claudin-1. LPL had similar effects to increase profilaggrin and SPT mRNA expression and also stimulated the expression of occludin and claudin-1 at the mRNA and protein levels. In accordance with these results, LPL elicited significant improvements in surface water content in human skin. These findings indicate that LPL has the potential to strengthen the skin moisturizing capability by up-regulating the expression of mRNAs encoding components important to skin barrier function and skin hydration.

Delayed bile leakage from a remaining part of segment 8 in a posterior section graft after living donor liver transplantation: a common pitfall in harvesting a posterior section graft? A case report.

In Japan and Korea, where availability of deceased donor organs for solid organ transplantation remains rare, living donor liver transplantation (LDLT) using a posterior section graft (PSG; segments VI+VII, according to Couinaud's Nomenclature for liver segmentation) has now been accepted as a standard procedure that balances donor risk and patient benefits for cases in which right hemi-liver donation is too risky, because of marked volume imbalances between right and left hemi-livers. Compared with other types of grafts, however, the procedure requires detailed knowledge concerning hepatic vascular anatomy and meticulous manipulation during donation surgery. We present herein a case of delayed bile leakage from a remaining part of segment 8 in a PSG, which was considered to be a complication peculiar to LDLT using a PSG.

Motor evoked potentials (MEPs) and H-reflexes are not equally sensitive to voluntary motor commands.

To investigate the sensitivity to changes in excitability of motoneuron pool dependent on voluntary motor commands, we recorded motor evoked potentials (MEPs) and H-reflexes from the right flexor carpi radialis (FCR) muscle of normal human subjects. Amplitudes of MEPs were always larger than those of the H-reflex in both tonic and phasic muscle contractions. Furthermore, amplitudes of MEP and H-reflex were larger in phasic than in tonic muscle contraction. These results indicate that there are differences in the sensitivity to changes in motoneuronal excitability related to the production of excitatory postsynaptic potentials for H-reflex and MEP responses, respectively.

Neural mechanisms of soleus H-reflex depression accompanying voluntary arm movement in standing humans.

This study have investigated the changes in soleus (Sol) H-reflexes by arm movement during freely standing (FS) and back-supported standing (BS) in healthy subjects. Before the arm movement, there is an anticipatory phase, which includes increased electromyographic (EMG) activity in the biceps femoris (BF) and decreased EMG activity of the Sol muscle. The Sol H-reflex appeared to be inhibited during the anticipatory phase as well as during the time of arm movement. However, the inhibition appeared to be larger in FS than in BS conditions. Vibration applied to the tendon of the BF muscle depressed the Sol H-reflex. This inhibition was attributed to presynaptic inhibition and was reduced during the anticipatory phase, and was not very much changed during arm movements. It is suggested that the depression of the Sol H-reflex induced by voluntary arm movement has two inhibitory components of different origins. Descending motor commands generate the early inhibitory component, while the late component is produced by the presynaptic inhibition that results from peripheral inputs. The inhibition related to anticipatory postural adjustment (APA) indicates that a new-setting of the spinal mechanisms is required and responsible in order to stabilize body equilibrium which is dependent upon different postural conditions.

Posture-dependent modulation of reciprocal inhibition upon initiation of ankle dorsiflexion in man.

The present study tested whether soleus H-reflex depression recorded from normal subjects during isotonic ankle dorsiflexion is due to reciprocal inhibition and this might be modulated by varying postures. The soleus H-reflex amplitude of eight healthy adults was investigated at various times prior to and during tibialis anterior discharge while subjects were seated and when standing. Results showed that the amount of soleus H-reflex depression was significantly larger in the standing than that in the sitting posture in spite of the same dorsiflexion movement. Furthermore, the depression upon initiation of dorsiflexion movement appeared earlier in the standing than in the sitting. The results suggest that increasing amounts of reciprocal inhibition are correlated with and dependent upon the preceding postural conditions for voluntary movement, i.e., modulation of reciprocal inhibition seems to be dictated by the difference in functional demand between sitting and standing posture.

Evidence for facilitation of motor evoked potentials (MEPs) induced by motor imagery.

This study examined the extent to which motor imagery can facilitate to specific pools of motoneurons. Motor commands induced by motor imagery were subthreshold for muscle activity and were presumably not associated with any change in background afferent activity. To estimate excitability changes of flexor carpi radialis (FCR) muscle motoneuron in spinal and cortical level, electric stimuli for recording H-reflex and transcranial magnetic stimulation (TMS) for recording motor evoked potentials (MEPs) were used. During motor imagery of wrist flexion, remarkable increases in the amplitude of the MEP of FCR were observed with no change in the H-reflex. Furthermore, facilitation of antagonist (extensor carpi radialis; ECR) was also observed. Therefore, it is concluded that internal motor command can activate precisely cortical excitability with no change in spinal level without recourse to afferent feedback.

EMG discharge patterns during human grip movement are task-dependent and not modulated by muscle contraction modes: a transcranial magnetic stimulation (TMS) study.

Our previous study revealed that, during tonic muscle contraction, remarkable functional differences among intrinsic and extrinsic muscles were observed during two different grip movements, i.e., precision and power grips. To verify whether this evidence is true even under the phasic muscle contraction, magnetic stimulation was delivered over the left scalp while a normal human subject performed phasic precision or power grip responses of the right-hand fingers in a simple reaction time (SRT) paradigm. Magnetic stimulation delivered during the latent period revealed different cortico-motoneuronal excitations between the two grip responses. In particular, the contributions of extensor carpi radialis (ECR) muscle were definitely different between the two grip responses, although motor-evoked potentials (MEPs) of first dorsal interosseous (FDI) prior to, and after EMG onset of movement initiation, were not different. These results were similar to previous results obtained during tonic muscle contraction. Thus, we have concluded that the task-dependent EMG discharge pattern in finger manipulation could not be modulated by muscle contraction modes.

Motor evoked potentials induced by motor imagery reveal a functional asymmetry of cortical motor control in left- and right-handed human subjects.

We investigated a functional hemispheric asymmetry of the human motor system between right- and left-handed subjects using motor evoked potentials (MEPs) in first dorsal interosseous (FDI) produced by transcranial magnetic stimulation (TMS). TMS was applied while the subject imaged flexing the index finger, the mechanical action that maximally potentiates MEPs in the FDI. In right-handers, MEP amplitudes induced by motor imagery of right (dominant hand) finger movement were significantly larger than those induced by mental imagery of left (non-dominant hand) finger movement. In left-handed individuals, however, these right-left differences in MEP amplitude were not observed. Thus, these differences in the degree of hemispheric asymmetry in right- and left-handed individuals might reflect corresponding differences in their cerebral organization.

Modulation of a motor evoked response to transcranial magnetic stimulation by the activity level of the first dorsal interosseous muscle in humans when grasping a stationary object with different grip widths.

A relation between corticospinal excitability and background voluntary muscular activity was investigated at low and high transcranial magnetic stimulation (TMS) intensities while grasping a stationary object with different widths (2 and 8 cm) using a precision grip. The muscle activity was recorded from the first dorsal interosseous muscle. Regression analysis revealed that there was a linear relation between the motor evoked potential (MEP) and background muscular activity for both grip widths at each of the TMS intensities. At the low TMS intensity, the slope of the regression lines was similar for the 2 and 8 cm grip widths. It was, however, different when the TMS intensity was high. The results suggested that sensitivity modulation of bias level (input) facilitation occurred with wider grip width. The results of this study would reflect to quantitative aspects of the relation between the synaptic drive to the motoneuron pool and the resulting efferent activity characterized, i.e. input-output relations of the human corticospinal pathway dependent on the occasion demand.

Effects of upper limb muscle vibration on human voluntary wrist flexion-extension movements.

The effect of upper limb muscle tendon vibration during alternating step flexion-extension movements about the wrist was studied in 6 normal humans. A vibrator was mounted over either the wrist flexor muscle or the elbow flexor and extensor muscles. Vibration was applied either to a single muscle or simultaneously to both muscles during wrist flexion-extension movements. After a period of practice, subjects learned the required movements and were able to make them with their eyes closed. Simultaneous application of subthreshold vibration to the wrist flexor and the elbow extensor or flexor muscles during extension movements produced an undershooting of the required end-movement position. The observed results indicated the pattern of transjoint projections from elbow extensor and flexor muscles to motoneurons supplying wrist extensor and flexor muscles. It is also suggested that those transjoint projections play an important role in coordinated movement of wrist and elbow joints.

An increase in cortical excitability with no change in spinal excitability during motor imagery.

During motor imagery, to estimate changes in excitability of flexor carpi radialis muscle motoneurons of the spinal and cortical levels, electrical stimuli for recording H-reflex and transcranial magnetic stimulation (TMS) for recording motor evoked potentials (MEPs) were used. In the absence of movement or detectable EMG activity during motor imagery, there was an increase in cortical excitability with no change in spinal excitability.

Influence of perturbation induced by an anticipated load on human motor regulatory systems.

To investigate how human motor regulatory systems are modified by prior knowledge of a predictable external perturbation, six normal human subjects, each when sitting on a chair, were required to maintain a stable elbow flexion angle (90 degrees) while different weight perturbations were applied (0.5 kg or 2-kg loads). Loads were applied either by the experimenter Without Anticipation or With Anticipation by the subject's own contralateral hand. Acceleration of the forearm movement (elbow extension and flexion) by loads and electromyograms (EMGs) of the biceps brachii (BB) and the triceps brachii (TB) muscle were recorded. Under With Anticipation conditions, preceding EMG activities of BB and TB muscles prior to the onset time of perturbation were clearly observed. Furthermore, the amount of these preceding EMG activities was larger in the heavy load perturbation than in the light load perturbation. Under Without Anticipation conditions, however, these preceding EMG activities were not observed. In the preceding EMG activities, EMG bursts (latency 20 msec.) of a presumed stretch reflex induced by the perturbation were clearly observed. Thus, the function of anticipatory adjustment of mainitaining the elbow angle definitely appears to optimize limb stability in the case of the mechanical self-applied perturbation. Furthermore, the extent of the anticipatory adjustment of the elbow angle was dependent on the predicted magnitude of load.

Dependence of deltoid muscle activity upon initial angles of shoulder abduction prior to flexion.

The present study was undertaken to investigate the hypothesis that the direction and selectivity of an appropriately modified version of shoulder flexion is dependent upon initial angles of shoulder abduction. Analysis indicated that initial small angles of shoulder abduction were associated with longer electromyographic (EMG) durations of the agonist (anterior deltoid) muscle. Moreover, as initial angles became smaller, EMG onsets of the antagonist (posterior deltoid muscle) occurred nearer to those of the agonist. Modulations of duration of the agonist EMG activity can be explained by changes in amplitude of movement. Two possible interpretations of the changes of EMG onset of the antagonist in accordance with different initial angles of shoulder abduction are considered. One concerns the effect of the change on the load of the upper limb, dependent on different angles of shoulder abduction. The second concerns the changing role of the antagonist to a synergist, dependent upon decreased initial angles of shoulder abduction prior to the shoulder flexion. Based on the present findings, it is suggested that angles of shoulder abduction are an important determinant of agonist-antagonist muscle activity of the deltoid during flexion of the shoulder.

[Antitumor spectrum of TUT-7 on rat ascitic hepatoma].

The antitumor activity of TUT-7, a new anthracycline compound, was compared to that of adriamycin in the screening system with rat ascites hepatomas. A marked antitumor effect was observed in most tumor lines, and the activity was assumed to be better than adriamycin.

Motor evoked potentials of the first dorsal interosseous muscle in step and ramp index finger abduction.

The present experiment was undertaken to study the change in motor cortex excitability as a function of muscle contraction speed during ramp and step abduction by the index finger. Motor evoked potentials (MEPs) of the first dorsal interosseous muscle elicited by transcranial magnetic stimulation (TMS) were modulated by different muscle contraction speeds. When TMS was delivered at 10% maximum voluntary contraction (MVC), MEP amplitudes were always significantly larger in step than in ramp contractions. These differences were dependent on the amount of background electromyographic activity (EMG), which was significantly larger in step than in ramp contractions. However, using maximum output of TMS (100%) with a trigger level at 10% MVC, these differences disappeared. With a trigger level at 30% MVC, these differences also disappeared in spite of differences in the amount of background EMG between them. These results are attributed to different central motor commands. Motor evoked potential amplitudes are dependent not only on the level of background EMG activity but also on the nature of descending motor commands.

Facilitation of motor evoked potentials (MEPs) in first dorsal interosseous (FDI) muscle is dependent on different motor images.

OBJECTIVE: We investigated changes in motor evoked potentials (MEPs) to explain why mental practice can improve motor performance. METHODS: MEPs were recorded from right and left first dorsal interosseous (FDI) muscles of 9 normal, right-handed subjects during different motor images of index finger movement: (1) rest, (2) flexion, (3) abduction, (4) extension. A paired t test was used to compare differences of stimulus intensities and MEP amplitudes among conditions. RESULTS: MEP amplitudes significantly increased in both FDI muscles during motor images of flexion and abduction but not of extension. Moreover, MEP amplitudes were larger in flexion than in abduction. These differences were proportional to the amount of real EMG discharge of FDI muscle in the selected direction of index finger movement. With regard to right-left differences, MEP amplitudes in the right FDI muscle were larger than those in the left. CONCLUSIONS: The primary motor cortex plays a role in the mental representation of motor acts. Furthermore, the amount of corticomotoneuronal cell activity is affected by the different motor images utilizing the same muscle. Right-left difference of MEP amplitude supports the view of left-hemisphere dominance for motor programming as an aspect of normal brain function among right-handers.

The effects of wrist muscle vibration on human voluntary elbow flexion-extension movements.

The effect of forearm muscle tendon vibration during alternating step flexion-extension movements about the elbow was studied in normal humans. In one experiment, a vibrator was mounted over either the forearm flexor or the extensor muscle. In a second experiment, a vibrator was mounted over either the forearm muscle or the biceps muscle. In both experiments, vibration was applied either to a single muscle or simultaneously to both muscles during elbow flexion-extension movements. After a period of practice, subjects learned the required movements and were able to make them with their eyes closed. Application of vibration to the forearm and the biceps muscle during extension movements produced an undershoot of the required end-movement position. Moreover, application of high-frequency vibration (100 Hz) to the forearm extensor and flexor muscle produced an overshoot of the required end-movement position. The observed results are consistent with vibration induced activation of muscle spindle receptors not only in the lengthening muscle during movement but also in the forearm muscles. It is suggested that the pattern of distribution of muscle spindle afferent from the forearm muscle onto alpha-motoneurons of muscles acting at the elbow has played an important role of alternating step flexion-extension movements.

Depletion of Bacillus subtilis histone-like protein, HBsu, causes defective protein translocation and induces upregulation of small cytoplasmic RNA.

Small cytoplasmic RNA (scRNA) is a metabolically stable homologue of mammalian SRP RNA that contains an Alu-like domain. The Bacillus subtilis histone-like protein HBsu can bind this domain. We demonstrate here that repressing the level of HBsu results in slow growth and the accumulation of precursor of beta-lactamase fusion proteins having the signal sequence of alkaline protease, penicillin binding protein 5* (PBP5*) or CGTase. The degree of the translocation defect varied among the various signal sequences tested. A pulse-chase experiment showed that processing the alpha-amylase signal sequence is significantly inhibited in HBsu-depleted cells. Northern blot analysis indicated that repressing the HBsu gene induces scRNA upregulation, indicating that the defective translocation of presecretory proteins is not due to a reduced scRNA level. The data presented here suggest that HBsu plays a pivotal role in SRP function rather than simply stabilizing the other SRP components such as scRNA.

Bacillus subtilis histone-like protein, HBsu, is an integral component of a SRP-like particle that can bind the Alu domain of small cytoplasmic RNA.

Small cytoplasmic RNA (scRNA) is metabolically stable and abundant in Bacillus subtilis cells. Consisting of 271 nucleotides, it is structurally homologous to mammalian signal recognition particle RNA. In contrast to 4.5 S RNA of Escherichia coli, B. subtilis scRNA contains an Alu domain in addition to the evolutionarily conserved S domain. In this study, we show that a 10-kDa protein in B. subtilis cell extracts has scRNA binding activity at the Alu domain. The in vitro binding selectivity of the 10-kDa protein shows that it recognizes the higher structure of the Alu domain of scRNA caused by five consecutive complementary sequences in the two loops. Purification and subsequent analyses demonstrated that the 10-kDa protein is HBsu, which was originally identified as a member of the histone-like protein family. By constructing a HBsu-deficient B. subtilis mutant, we showed that HBsu is essential for normal growth. Immunoprecipitating cell lysates using anti-HBsu antibody yielded scRNA. Moreover, the co-precipitation of HBsu with (His)6-tagged Ffh depended on the presence of scRNA, suggesting that HBsu, Ffh, and scRNA make a ternary complex and that scRNA serves as a functional unit for binding. These results demonstrated that HBsu is the third component of a signal recognition particle-like particle in B. subtilis that can bind the Alu domain of scRNA.

Further insight into the task-dependent excitability of motor evoked potentials in first dorsal interosseous muscle in humans.

We have reexamined the contradictory evidence in which task-dependent excitation of motor evoked potentials (MEPs) in the first dorsal interosseous (FDI) muscle was stronger with increasingly more complex finger tasks than with individual finger movement tasks. In the first step of the experiment, based on previous findings, we investigated remarkable functional differences between intrinsic and extrinsic hand muscles during complex finger tasks (precision and power grip). During the performance of the tasks, the optimal stimulus intensity of the transcranial magnetic stimulation (TMS) was applied to the contralateral motor cortex. MEPs of the FDI, extensor carpi radialis (ECR), and flexor carpi radialis (FCR) muscles were recorded simultaneously with increased background EMG activity step by step in both tasks. The intensity threshold of TMS was lower in the precision grip. Furthermore, the MEP amplitudes of FDI muscle dependent on the background EMG activity were different between these two tasks, i.e., MEP amplitudes and regression coefficients in a precision grip were larger than those in a power grip. Although our results for MEP amplitude and threshold in the FDI muscle were similar to previous reported evidence, the different contributions of a synergistic muscle (in particular, the ECR muscle) during performance in these tasks was new evidence. Since there were no differences in cutaneous afferent effects on both tasks, corticomotoneuronal (CM) cells connected to FDI motoneurons seemed generally to be more active during precision than power gripping, and there were different contributions from synergistic muscles during the performance of these tasks. In the second part of the experiment, the results obtained from the complex tasks were compared with those from a simple task (isolated index finger flexion). MEP amplitudes, dependent on the background EMG activity during isolated index finger flexion, varied among subjects, i.e., the relationship between the MEP amplitude and the background EMG of the FDI muscle showed individual, strategy-dependent modulation. There were several kinds of individual motor strategies for performing the isolated finger movement. The present results may explain the previous contradictory evidence related to the contribution of the CM system during coordinated finger movement.