A review of psychological and neuroscientific research on musical groove

When listening to music, we naturally move our bodies rhythmically to the beat, which can be pleasurable and difficult to resist. This pleasurable sensation of wanting to move the body to music has been called "groove." Following pioneering humanities research, psychological and neuroscientific studies have provided insights on associated musical features, behavioral responses, phenomenological aspects, and brain structural and functional correlates of the groove experience. Groove research has advanced the field of music science and more generally informed our understanding of bidirectional links between perception and action, and the role of the motor system in prediction. Activity in motor and reward-related brain networks during music listening is associated with the groove experience, and this neural activity is linked to temporal prediction and learning. This article reviews research on groove as a psychological phenomenon with neurophysiological correlates that link musical rhythm perception, sensorimotor prediction, and reward processing. Promising future research directions range from elucidating specific neural mechanisms to exploring clinical applications and socio-cultural implications of groove.

Is happier music groovier? The influence of emotional characteristics of musical chord progressions on groove

Specific rhythmic patterns in music have been reported to induce an urge to move with feelings of pleasure or enjoyment, called "groove." However, it is unclear how the emotional characteristics of music (e.g., happiness or sadness) affect groove. To address this issue I investigated the effects of the emotional characteristics of music on groove by altering the chord progressions accompanying drum breaks composed by a professional composer while manipulating independent tempo and rhythmic patterns. An online listening experiment was conducted using pieces composed by a professional composer but comprising different types of chord progressions that lead to happiness or sadness. Participants evaluated the nine items on a 7-point scale, including urge to move (i.e., groove), felt emotions, nori, and liking. The experiment found that: (1) chord progressions that evoke happiness were more likely to induce groove, (2) emotional characteristics did not interact with tempi and syncopation in terms of groove ratings, and (3) the accompaniment of drum breaks enhanced groove in both happy and sad chord progressions. Musical pieces with chord progressions that induce happiness were more likely to evoke groove, namely the urge to move. This implies that considering the emotional characteristics of musical pieces and rhythms is crucial when creating music for movement during rehabilitation, therapy, or dance.

Groove Rhythm Enhances Exercise Impact on Prefrontal Cortex Function in Groove Enjoyers

A positive affective response modulates the effects of aerobic exercise on prefrontal executive function (EF). Groove rhythm (GR), eliciting the feeling of wanting to move to music, is useful for inducing positive affective response during exercise. Three minutes of listening to GR activated the left dorsolateral prefrontal cortex (l-DLPFC) and enhanced EF in participants who had higher psychological responses to GR. This finding prompted us to test the hypothesis that the combination of GR and exercise (GREX) induces positive psychological responses that enhance PFC function through entrainment of body movements and musical beats. 41 participants were administered two experimental conditions: three min of very light-intensity (30% V̇ O2peak) exercise combined with GR and combined with a white-noise metronome (WMEX). Before and after exercise, participants performed a Stroop task and were monitored for l-DLPFC activity with functional near-infrared spectroscopy. GREX enhanced EF and l-DLPFC activity in participants who experienced greater subjective feelings of audiomotor entrainment and increased excitement with GREX. These psychological responses were predictive of the impact of GREX on l-DLPFC activity and EF. These findings, together with previous results, support the hypothesis that GR allows us to boost the cognitive benefits of exercise via l-DLPFC activity only in those who enjoy groove, and suggest that subjective audiomotor entrainment is a key mechanism of this boosting effect.

First observation of 28O

Subjecting a physical system to extreme conditions is one of the means often used to obtain a better understanding and deeper insight into its organization and structure. In the case of the atomic nucleus, one such approach is to investigate isotopes that have very different neutron-to-proton (N/Z) ratios than in stable nuclei. Light, neutron-rich isotopes exhibit the most asymmetric N/Z ratios and those lying beyond the limits of binding, which undergo spontaneous neutron emission and exist only as very short-lived resonances (about 10-21 s), provide the most stringent tests of modern nuclear-structure theories. Here we report on the first observation of 28O and 27O through their decay into 24O and four and three neutrons, respectively. The 28O nucleus is of particular interest as, with the Z = 8 and N = 20 magic numbers1,2, it is expected in the standard shell-model picture of nuclear structure to be one of a relatively small number of so-called 'doubly magic' nuclei. Both 27O and 28O were found to exist as narrow, low-lying resonances and their decay energies are compared here to the results of sophisticated theoretical modelling, including a large-scale shell-model calculation and a newly developed statistical approach. In both cases, the underlying nuclear interactions were derived from effective field theories of quantum chromodynamics. Finally, it is shown that the cross-section for the production of 28O from a 29F beam is consistent with it not exhibiting a closed N = 20 shell structure.

Perspectives of teachers at music schools toward children's extra-musical abilities promoted by music lessons

Musical activities foster children's social ability. However, the question remains whether professional music teachers consider musical training to have an influence on extra-musical abilities or only on the acquisition of musical skills. We conducted an online survey to collect open-ended responses regarding this question from over 2,000 music teachers in one of the biggest extracurricular fee-charging music school groups in Japan. Teachers' free descriptions were classified into non-cognitive skills, and frequently occurring words were extracted through text mining. The results showed that, although the primary goal of music teachers who provide fee-charging lessons may be to teach musical skills to their students, they were aware of the effects of music lessons on children's non-cognitive development. Our study's main findings include: (1) despite free-descriptions, 92% of teachers reported that children acquired extra-musical abilities, and 98% of these responses were categorized as non-cognitive skills, (2) the most common responses within non-cognitive skills were "collaboration," "task performance," and "engaging with others", and (3) there was a significant positive correlation between teaching experience and frequency of mentioning non-cognitive skills. Views on extra-musical abilities, which experienced music teachers especially had, may improve less-experienced teachers' perspectives on teaching as well as their social roles and occupational awareness.

Mapping of a New Deformation Region around ^{62}Ti

We performed the first direct mass measurements of neutron-rich scandium, titanium, and vanadium isotopes around the neutron number 40 at the RIKEN RI Beam Factory using the time-of-flight magnetic-rigidity technique. The atomic mass excesses of ^{58-60}Sc, ^{60-62}Ti, and ^{62-64}V were measured for the first time. The experimental results show that the two-neutron separation energies in the vicinity of ^{62}Ti increase compared to neighboring nuclei. This shows that the masses of Ti isotopes near N=40 are affected by the Jahn-Teller effect. Therefore, a development of Jahn-Teller stabilization appears below the Cr isotopes, and the systematics in Sc, Ti, and V isotopes suggest that ^{62}Ti is located close to the peak of the Jahn-Teller effect.

How Different is the Core of ^{25}F from ^{24}O_{g.s.} ?

The structure of a neutron-rich ^{25}F nucleus is investigated by a quasifree (p,2p) knockout reaction at 270A  MeV in inverse kinematics. The sum of spectroscopic factors of π0d_{5/2} orbital is found to be 1.0±0.3. However, the spectroscopic factor with residual ^{24}O nucleus being in the ground state is found to be only 0.36±0.13, while those in the excited state is 0.65±0.25. The result shows that the ^{24}O core of ^{25}F nucleus significantly differs from a free ^{24}O nucleus, and the core consists of ∼35% ^{24}O_{g.s.}. and ∼65% excited ^{24}O. The result may infer that the addition of the 0d_{5/2} proton considerably changes neutron structure in ^{25}F from that in ^{24}O, which could be a possible mechanism responsible for the oxygen dripline anomaly.

Extending the Southern Shore of the Island of Inversion to ^{28}F

Detailed spectroscopy of the neutron-unbound nucleus ^{28}F has been performed for the first time following proton/neutron removal from ^{29}Ne/^{29}F beams at energies around 230  MeV/nucleon. The invariant-mass spectra were reconstructed for both the ^{27}F^{(*)}+n and ^{26}F^{(*)}+2n coincidences and revealed a series of well-defined resonances. A near-threshold state was observed in both reactions and is identified as the ^{28}F ground state, with S_{n}(^{28}F)=-199(6)  keV, while analysis of the 2n decay channel allowed a considerably improved S_{n}(^{27}F)=1620(60)  keV to be deduced. Comparison with shell-model predictions and eikonal-model reaction calculations have allowed spin-parity assignments to be proposed for some of the lower-lying levels of ^{28}F. Importantly, in the case of the ground state, the reconstructed ^{27}F+n momentum distribution following neutron removal from ^{29}F indicates that it arises mainly from the 1p_{3/2} neutron intruder configuration. This demonstrates that the island of inversion around N=20 includes ^{28}F, and most probably ^{29}F, and suggests that ^{28}O is not doubly magic.

LC-MS analysis of saponins of Achyranthes root in the Japanese market

LC-MS analyses of saponin fractions of Achyranthes roots in the Japanese market revealed that there were three patterns for the saponin fraction of their water extracts, i.e., the saponins with a sugar moiety at position 28 [achyranthosides B (3), C (4) and D (5)] were the major constituents, the saponins without sugar moiety at position 28 [betavulgarosides II (10) and IV (11)] were the major constituents, and mixtures of these saponins. In a decoction prepared from the sample which contained 10 and 11 as the major saponins, their amounts were largely decreased compared with those of the water extract. As large amounts of these saponins were found in the precipitates formed by heating of the water extract, these saponins were seemed to precipitate out under heating. When hot water was used for the extraction, 3, 4 and 5 were detected even from the samples whose water extract did not contain these saponins. This was attributed to inhibition of endogenous esterase which hydrolyzes the ester linkage at position 28. When saponins were extracted with reagent grade 1-butanol, in addition to the decrease of the amounts of highly polar saponins, oxidative decarboxylation of 3 and 10 occurred resulting in formation of achyranthoside E (6) and spinacoside D (12), respectively. As these changes were not observed with HPLC grade 1-butanol, which contain not more than 5 ppm of peroxide impurities, the change was attributable to the peroxide impurities contained in the reagent grade 1-butanol.

An Investigation Into the Relationship Between Onset Age of Musical Lessons and Levels of Sociability in Childhood

Previous studies have suggested that musical training in childhood is beneficial for sociability. However, it remains unclear how age of onset of group music lessons is associated with the late sociability of children from a long-term perspective. This study investigated associations between group music lessons conducted at a music school and children's levels of sociability by focusing on the age of onset of the lessons. We conducted a survey of 276 children aged 4-5 years (M = 58.5 months) and 6-7 years (M = 82.7 months) who commenced music lessons at ages 1, 2, 4, and 6 years. We found that (1) the empathy scores of children aged 6-7 years who began lessons when 1-year-old were greater than those who began lessons when 4-years-old, (2) the communication scores of children aged 4-5 years who began lessons when 1-year-old were greater than those who began lessons when older than 1 year, and (3) the empathy and extraversion scores were high in those aged 6-7 years who began lessons in that age range. The results suggest that early onset of music lessons could positively influence children's sociability; in contrast, after about age 7 years, children who already had high sociability may be more inclined to select group music lessons. By focusing on the impact of regular group music lessons from a very young age on later levels of sociability, these results further elucidate the effects of musical lessons. In sum, participation in group music lessons 2-4 times per month can be effective social training for very young children and foster their later sociability.

Magic Nature of Neutrons in ^{54}Ca: First Mass Measurements of ^{55-57}Ca

We perform the first direct mass measurements of neutron-rich calcium isotopes beyond neutron number 34 at the RIKEN Radioactive Isotope Beam Factory by using the time-of-flight magnetic-rigidity technique. The atomic mass excesses of ^{55-57}Ca are determined for the first time to be -18650(160), -13510(250), and -7370(990)  keV, respectively. We examine the emergence of neutron magicity at N=34 based on the new atomic masses. The new masses provide experimental evidence for the appearance of a sizable energy gap between the neutron 2p_{1/2} and 1f_{5/2} orbitals in ^{54}Ca, comparable to the gap between the neutron 2p_{3/2} and 2p_{1/2} orbitals in ^{52}Ca. For the ^{56}Ca nucleus, an open-shell property in neutrons is suggested.

Excitation of the Isovector Spin Monopole Resonance via the Exothermic ^{90}Zr(^{12}N,^{12}C) Reaction at 175 MeV/u

The (^{12}N, ^{12}C) charge-exchange reaction at 175  MeV/u was developed as a novel probe for studying the isovector spin giant monopole resonance (IVSMR), whose properties are important for better understanding the bulk properties of nuclei and asymmetric nuclear matter. This probe, now available through the production of ^{12}N as a secondary rare-isotope beam, is exothermic, is strongly absorbed at the surface of the target nucleus, and provides selectivity for spin-transfer excitations. All three properties enhance the excitation of the IVSMR compared to other, primarily light-ion, probes, which have been used to study the IVSMR thus far. The ^{90}Zr(^{12}N,^{12}C) reaction was measured and the excitation energy spectra up to about 70 MeV for both the spin-transfer and non-spin-transfer channels were deduced separately by tagging the decay by γ emission from the ^{12}C ejectile. Besides the well-known Gamow-Teller and isobaric analog transitions, a clear signature of the IVSMR was identified. By comparing with the results from light-ion reactions on the same target nucleus and theoretical predictions, the suitability of this new probe for studying the IVSMR was confirmed.

Spectroscopy of Pionic Atoms in ^{122}Sn(d,^{3}He) Reaction and Angular Dependence of the Formation Cross Sections

We observed the atomic 1s and 2p states of π^{-} bound to ^{121}Sn nuclei as distinct peak structures in the missing mass spectra of the ^{122}Sn(d,^{3}He) nuclear reaction. A very intense deuteron beam and a spectrometer with a large angular acceptance let us achieve a potential of discovery, which includes the capability of determining the angle-dependent cross sections with high statistics. The 2p state in a Sn nucleus was observed for the first time. The binding energies and widths of the pionic states are determined and found to be consistent with previous experimental results of other Sn isotopes. The spectrum is measured at finite reaction angles for the first time. The formation cross sections at the reaction angles between 0° and 2° are determined. The observed reaction-angle dependence of each state is reproduced by theoretical calculations. However, the quantitative comparison with our high-precision data reveals a significant discrepancy between the measured and calculated formation cross sections of the pionic 1s state.

Optimal Tempo for Groove: Its Relation to Directions of Body Movement and Japanese nori

The tendency for groove-based music to induce body movements has been linked to multiple acoustical factors. However, it is unclear how or whether tempo affects groove, although tempo significantly affects other aspects of music perception. To address this issue, the present study investigated effects of tempo, specific rhythmic organizations of patterns, and syncopation on groove and the induction of the sensation of wanting to move. We focused on the directions of body movement in particular by taking into account nori, which is an indigenous Japanese musical term used not only synonymously with groove, but also as a spatial metaphor indicating vertical or horizontal movement directions. Thus, the present study explored how groove was felt and defined, as well as how musical factors induced the sensation of wanting to move in cross-cultural context. A listening experiment was conducted using drum breaks as stimuli. Stimuli consisted of various rhythm patterns at six tempi from 60 to 200 BPM. The main findings are that: (1) an optimal tempo for groove existed for drum breaks at around 100–120 BPM, (2) an optimal tempo existed for the sensation of wanting to move the body in specific directions (i.e., back-and-forth and side-to-side), (3) groove and nori shared a similar concept of wanting to move but differed on several points (i.e., association with sense of pulse and fast tempo). Overall, the present study suggests that there is an optimal tempo for body movement related to groove. This finding has implications for the use of music or rhythmic stimuli to induce smooth motion in rehabilitation, therapy, or dance.

Enteric Glial Dysfunction Evoked by Apolipoprotein E Deficiency Contributes to Delayed Gastric Emptying

BACKGROUND AND AIM

Diabetes is the main cause of gastroparesis accompanying decreased neuronal nitric oxide synthase (nNOS) in myenteric ganglia of the stomach. Decreased nNOS expression in the stomach also results from defects in apolipoprotein E (ApoE), which is secreted by astrocytes and has neuroprotective effects on the central nervous system. However, the roles of ApoE and enteric glial cells on gastric motility are uncertain. In this study, ApoE and enteric glial cell alterations in gastroparesis were investigated.

METHODS

Type 2 diabetic (db/db) mice and ApoE-knockout mice were analyzed. Gastric emptying was measured using the ¹³C acetic acid breath test. Expression levels of the pan-neuronal marker, protein gene product 9.5 (PGP 9.5), and glial marker, glial fibrillary acidic protein (GFAP) were examined by immunohistochemistry. Neural stem cells (NSCs) were injected into the gastric antral wall of ApoE-knockout mice.

RESULTS

Delayed gastric emptying was observed in 27% of db/db mice with significant decreases in serum ApoE levels and GFAP expression in the gastric antrum. Gastric emptying was also delayed in ApoE-knockout mice, with a significant decrease in GFAP expression, but no change in PGP 9.5 expression. Transplantation of NSCs improved gastric emptying in ApoE-knockout mice through supplementation of GFAP-positive cells.

CONCLUSIONS

Our results suggest that decreased enteric glial cells in ApoE-knockout mice are crucial for development of delayed gastric emptying, and NSC transplantation is effective in restoring myenteric ganglia and gastric motility.

Regulation of RhoA by STAT3 coordinates glial scar formation

The transcription factor STAT3 is known to control glial scar formation, but the underlying mechanism is unknown. Renault-Mihara et al. show that inhibition of the small GTPase RhoA by STAT3 coordinates reactive astrocyte dynamics during glial scar formation.

Understanding how the transcription factor signal transducer and activator of transcription–3 (STAT3) controls glial scar formation may have important clinical implications. We show that astrocytic STAT3 is associated with greater amounts of secreted MMP2, a crucial protease in scar formation. Moreover, we report that STAT3 inhibits the small GTPase RhoA and thereby controls actomyosin tonus, adhesion turnover, and migration of reactive astrocytes, as well as corralling of leukocytes in vitro. The inhibition of RhoA by STAT3 involves ezrin, the phosphorylation of which is reduced in STAT3-CKO astrocytes. Reduction of phosphatase and tensin homologue (PTEN) levels in STAT3-CKO rescues reactive astrocytes dynamics in vitro. By specific targeting of lesion-proximal, reactive astrocytes in Nestin-Cre mice, we show that reduction of PTEN rescues glial scar formation in Nestin-Stat3^+/− mice. These findings reveal novel intracellular signaling mechanisms underlying the contribution of reactive astrocyte dynamics to glial scar formation.

Audience gaze while appreciating a multipart musical performance

Visual information has been observed to be crucial for audience members during musical performances. The present study used an eye tracker to investigate audience members' gazes while appreciating an audiovisual musical ensemble performance, based on evidence of the dominance of musical part in auditory attention when listening to multipart music that contains different melody lines and the joint-attention theory of gaze. We presented singing performances, by a female duo. The main findings were as follows: (1) the melody part (soprano) attracted more visual attention than the accompaniment part (alto) throughout the piece, (2) joint attention emerged when the singers shifted their gazes toward their co-performer, suggesting that inter-performer gazing interactions that play a spotlight role mediated performer-audience visual interaction, and (3) musical part (melody or accompaniment) strongly influenced the total duration of gazes among audiences, while the spotlight effect of gaze was limited to just after the singers' gaze shifts.

Candidate Resonant Tetraneutron State Populated by the ^{4}He(^{8}He,^{8}Be) Reaction

A candidate resonant tetraneutron state is found in the missing-mass spectrum obtained in the double-charge-exchange reaction ^{4}He(^{8}He,^{8}Be) at 186  MeV/u. The energy of the state is 0.83±0.65(stat)±1.25(syst)  MeV above the threshold of four-neutron decay with a significance level of 4.9σ. Utilizing the large positive Q value of the (^{8}He,^{8}Be) reaction, an almost recoilless condition of the four-neutron system was achieved so as to obtain a weakly interacting four-neutron system efficiently.

Safety management of nuclear medicine personnel with visualisation of air dose rate

Many people are anxious about radiation exposure for the reason that radiation cannot be seen. With the aim of devising a way for medical personnel to perform their medical duties without worry about radiation exposure, we attempted safety management using a system that displays the air dose of radiation in real time. Measurements were made in a lung ventilation scintigraphy examination room with the use of Xe-133. An SCI-type RI detector from Hamamatsu Photonics, which displays the air dose rate in real time, was used for the measurements. These radiation measurements were continued from the start to finish of the examination. The measurements were made in two locations, on the patient inhalation tube side and on the opposite side. Measurements were made on the patient tube side in 24 tests and on the opposite side in 12 tests. The maximum air dose rate was 3.7 ± 2.1 μSv/h on the patient tube side and 1.1 ± 0.5 μSv/h on the opposite side. Thus, the level on the opposite side was about 1/5 that of the tube side. To accurately perform lung ventilation scintigraphy, a medical worker needs to observe the patient's breathing status up close. Because of this, some medical workers are worried about radiation exposure during tests. The simplest way to reduce exposure would be to maintain a distance from the examination tube that is the source of radiation. The measurements in this study were made to encourage medical workers' recognition of this fact. Displaying specific numbers not only serves as basic data for managing staff operations, but is also thought to reassure workers through visualization.

Regulatory factor X transcription factors control Musashi1 transcription in mouse neural stem/progenitor cells

The transcriptional regulation of neural stem/progenitor cells (NS/PCs) is of great interest in neural development and stem cell biology. The RNA-binding protein Musashi1 (Msi1), which is often employed as a marker for NS/PCs, regulates Notch signaling to maintain NS/PCs in undifferentiated states by the translational repression of Numb expression. Considering these critical roles of Msi1 in the maintenance of NS/PCs, it is extremely important to elucidate the regulatory mechanisms by which Msi1 is selectively expressed in these cells. However, the mechanism regulating Msi1 transcription is unclear. We previously reported that the transcriptional regulatory region of Msi1 is located in the sixth intron of the Msi1 locus in NS/PCs, based on in vitro experiments. In the present study, we generated reporter transgenic mice for the sixth intronic Msi1 enhancer (Msi1-6IE), which show the reporter expression corresponding with endogenous Msi1-positive cells in developing and adult NS/PCs. We found that the core element responsible for this reporter gene activity includes palindromic Regulatory factor X (Rfx) binding sites and that Msi1-6IE was activated by Rfx. Rfx4, which was highly expressed in NS/PCs positive for the Msi1-6IE reporter, bound to this region, and both of the palindromic Rfx binding sites were required for the transactivation of Msi1-6IE. Furthermore, ectopic Rfx4 expression in the developing mouse cerebral cortex transactivates Msi1 expression in the intermediate zone. This study suggests that ciliogenic Rfx transcription factors regulate Msi1 expression through Msi1-6IE in NS/PCs.

Identification of the β+ isovector spin monopole resonance via the 208Pb and 90Zr(t,3He) reactions at 300 MeV/u

The double-differential cross sections for the (208)Pb and (90)Zr(t,(3)He) reactions at 300 MeV/u have been measured at the RI Beam Factory at RIKEN. This was the first physics experiment with the SHARAQ magnetic spectrometer. The combined analysis of the present (t,(3)He) data and previous (n,p) data provides the clearest identification for the β(+) isovector spin monopole resonance both in the (208)Tl and (90)Y nuclei, and puts the observations of this giant resonance on a firm foundation. The measured distributions of the (t,(3)He) monopole cross sections were well reproduced by the distorted-wave Born approximation calculation, where the target transition density was calculated with the self-consistent Hartree-Fock plus random-phase approximation using the T43 Skyrme interaction. A major part of the expected β(+) isovector spin monopole strength was found in the measured cross section spectra.

Identification of a novel intronic enhancer responsible for the transcriptional regulation of musashi1 in neural stem/progenitor cells

Background

The specific genetic regulation of neural primordial cell determination is of great interest in stem cell biology. The Musashi1 (Msi1) protein, which belongs to an evolutionarily conserved family of RNA-binding proteins, is a marker for neural stem/progenitor cells (NS/PCs) in the embryonic and post-natal central nervous system (CNS). Msi1 regulates the translation of its downstream targets, including m-Numb and p21 mRNAs. In vitro experiments using knockout mice have shown that Msi1 and its isoform Musashi2 (Msi2) keep NS/PCs in an undifferentiated and proliferative state. Msi1 is expressed not only in NS/PCs, but also in other somatic stem cells and in tumours. Based on previous findings, Msi1 is likely to be a key regulator for maintaining the characteristics of self-renewing stem cells. However, the mechanisms regulating Msi1 expression are not yet clear.

Results

To identify the DNA region affecting Msi1 transcription, we inserted the fusion gene ffLuc, comprised of the fluorescent Venus protein and firefly Luciferase, at the translation initiation site of the mouse Msi1 gene locus contained in a 184-kb bacterial artificial chromosome (BAC). Fluorescence and Luciferase activity, reflecting the Msi1 transcriptional activity, were observed in a stable BAC-carrying embryonic stem cell line when it was induced toward neural lineage differentiation by retinoic acid treatment. When neuronal differentiation was induced in embryoid body (EB)-derived neurosphere cells, reporter signals were detected in Msi1-positive NSCs and GFAP-positive astrocytes, but not in MAP2-positive neurons. By introducing deletions into the BAC reporter gene and conducting further reporter experiments using a minimized enhancer region, we identified a region, "D5E2," that is responsible for Msi1 transcription in NS/PCs.

Conclusions

A regulatory element for Msi1 transcription in NS/PCs is located in the sixth intron of the Msi1 gene. The 595-bp D5E2 intronic enhancer can transactivate Msi1 gene expression with cell-type specificity markedly similar to the endogenous Msi1 expression patterns.

Autonomous right-screw rotation of growth cone filopodia drives neurite turning

The clockwise turning of neurites is caused by the rotations of filopodia as they extend and sweep across the substratum.

The direction of neurite elongation is controlled by various environmental cues. However, it has been reported that even in the absence of any extrinsic directional signals, neurites turn clockwise on two-dimensional substrates. In this study, we have discovered autonomous rotational motility of the growth cone, which provides a cellular basis for inherent neurite turning. We have developed a technique for monitoring three-dimensional motility of growth cone filopodia and demonstrate that an individual filopodium rotates on its own longitudinal axis in the right-screw direction from the viewpoint of the growth cone body. We also show that the filopodial rotation involves myosins Va and Vb and may be driven by their spiral interactions with filamentous actin. Furthermore, we provide evidence that the unidirectional rotation of filopodia causes deflected neurite elongation, most likely via asymmetric positioning of the filopodia onto the substrate. Although the growth cone itself has been regarded as functionally symmetric, our study reveals the asymmetric nature of growth cone motility.

Hypergastrinaemia induced by partial corpectomy results in development of enterochromaffin-like cell carcinoma in male Japanese cotton rats

BACKGROUND

Among inbred female cotton rats (Sigmodon hispidus) 25%-50% of the animals develop spontaneous gastric carcinomas, whereas males have an incidence of less than 1%. The carcinomas are enterochromaffin-like (ECL)-cell derived. Animals with gastric carcinomas also have hypergastrinaemia and gastric hypoacidity, but the mechanism behind the hypoacidity is unknown. Carcinomas have been found in all female cotton rats with spontaneous hypergastrinaemia lasting more than 4 months, and a gastrin receptor antagonist prevents the development of carcinoma. The purpose of the present study was to investigate whether induced hypergastrinaemia in male cotton rats would also result in carcinomas.

METHODS

Hypergastrinaemia was induced by partial corpectomy of male cotton rats, aiming at removal of 80%-90% of the corpus. A control group was sham-operated.

RESULTS

All partially corpectomized animals developed persistent hypergastrinaemia. Six months after the operation, 9 out of 13 partially corpectomized animals developed gastric cancer. In the dysplastic mucosa surrounding the tumours there was an increase in chromogranin A immunoreactive cells, where numerous cells also were stained using the Sevier-Munger technique. Tumour tissue also contained cells that were chromogranin A positive and stained by Sevier-Munger.

CONCLUSIONS

ECL-cell carcinomas can be induced in male cotton rats by partial corpectomy. This supports a previous statement that spontaneous carcinomas in female cotton rats are caused by gastric hypoacidity and hypergastrinaemia. In hypergastrinaemic animals, ECL-cell carcinomas develop independently of gender within a relatively short period of time, and cotton rats therefore represent an interesting model for studying gastric carcinogenesis.

Spontaneous enterochromaffin-like cell carcinomas in cotton rats (Sigmodon hispidus) are prevented by a somatostatin analogue

Among inbred female cotton rats (Sigmodon hispidus) 25-50% of the animals develop spontaneous gastric carcinomas; the corresponding figure for male cotton rats is approximately 1%. Animals with carcinomas have hypergastrinaemia and gastric hypo-anacidity and the tumours are derived from enterochromaffin-like (ECL) cells. The mechanism behind the hypo-anacidity is unknown. Carcinomas are found in all female cotton rats with hypergastrinaemia lasting more than 4 months and this represents an excellent animal model for studying gastric carcinogenesis. In this study, the somatostatin analogue octreotide was given to female cotton rats to prevent carcinoma development caused by hypergastrinaemia. Twelve female cotton rats were given monthly injections of long-acting octreotide (5 mg i.m.) for 6 months. A control group of 20 animals was not given injections. Of the 20 control animals, 13 developed hypergastrinaemia and histologically invasive carcinomas or dysplasia. Of the 12 animals in the octreotide group, five developed hypergastrinaemia. None of these five animals developed histological cancer (P<0.05), whereas three had dysplasia. However, octreotide did not affect plasma gastrin concentration or antral gastrin mRNA abundance significantly. Dysplasia of the oxyntic mucosa in hypergastrinaemic animals was accompanied by a marked increase in chromogranin A-immunoreactive cells and cells positive for Sevier-Munger staining. The malignant tissue also contained groups of cells with Sevier-Munger staining. In conclusion, octreotide prevented ECL cell carcinomas in hypergastrinaemic cotton rats without lowering the gastrin concentration.

Upgrading rural Japanese nurses' respiratory rehabilitation skills through videoconferencing

We examined the effect of distance learning on nurses' clinical skills in a rural Japanese hospital. The subject matter was respiratory rehabilitation. After one face-to-face session, who 30 min sessions were delivered by videoconferencing to staff nurses working in a 100-bed rural hospital 250 miles (400 km) from Sapporo Medical University. A self-rating questionnaire was distributed before and after the sessions. Responses were collected from 15 out of 32 nurses participating in the face-to-face session (47%). Before the first videoconferencing session, 'always use' and 'sometime use' the new skills were rated by 67% of nurses, but after the second videoconferencing session 'always use' and 'sometimes use' were rated by 73% and 'never use' at 0%. This implies that there was increased use of new skills after the second session, although the difference was not significant. The nurses' opinions about the effectiveness for patients increased from 8% to 27% after the second session, which was significant. The pilot project indicated the usefulness of distance learning for upgrading nurses' clinical practice in one rural Japanese hospital and suggested ways in which videoconferencing can be used in future.

Replacement set mutagenesis of the four phosphate-binding arginine residues of thymidylate synthase

Arginines R23, R178, R179 and R218 in thymidylate synthase (TS, EC 2. 1.1.45) are hydrogen bond donors to the phosphate moiety of the substrate, dUMP. In order to investigate how these arginines contribute to enzyme function, we prepared complete replacement sets of mutants at each of the four sites in Lactobacillus casei TS. Mutations of R23 increase K:(m) for dUMP 2-20-fold, increase K:(m) for cofactor 8-40-fold and decrease k(cat) 9-20-fold, reflecting the direct role of the R23 side chain in binding and orienting the cofactor in ternary complexes of the enzyme. Mutations of R178 increase K:(m) for dUMP 40-2000-fold, increase K:(m) for cofactor 3-20-fold and do not significantly affect k(cat). These results are consistent with the fact that this residue is an integral part of the dUMP-binding wall and contributes to the orientation and ordering of several other dUMP binding residues. Kinetic parameters for all R179 mutations except R179P were not significantly different from wild-type values, reflecting the fact that this external arginine does not directly contact the cofactor or other ligand-binding residues. R218 is essential for the structure of the catalytic site and all mutations of this arginine except R218K were inactive.

Indirect amperometric detection of underivatized amino acids in microcolumn liquid chromatography with carbon film based ring-disk electrodes

An indirect amperometric detection of underivatized amino acids has been developed using a carbon film based ring-disk electrode (CFBRDE) in microcolumn liquid chromatography (LC). Bromide present in the mobile phase could be efficiently oxidized to bromine at the upstream (disk) electrode, and was subsequently detected at the downstream (ring) electrode. Most of the underivatized amino acids that are electroinactive under conventional amperometric conditions react rapidly with the electrogenerated bromine, the concentration of amino acids can therefore be indirectly determined by continuously monitoring the reduction current of bromine. The signal monitored at the downstream electrode was largely dependent on the bromide concentration in the mobile phase. Under optimized conditions, the response linearly increased with the concentration for most of the amino acids over a concentration range of 1-100 microM, with a correlation coefficient of 0.990-0.993. The detection limits for most of the amino acids were below 1 microM (0.2 pmol). It was demonstrated that detection with a ring-disk electrode offers the advantages of achieving a much higher collection efficiency caused by a decrease in flow rate in the microcolumn LC.

Energetic contributions of four arginines to phosphate-binding in thymidylate synthase are more than additive and depend on optimization of "effective charge balance"

In thymidylate synthase, four conserved arginines provide two hydrogen bonds each to the oxygens of the phosphate group of the substrate, 2'-deoxyuridine-5'-monophosphate. Of these, R23, R178, and R179 are far removed from the site of methyl transfer and contribute to catalysis solely through binding and orientation of ligands. These arginines can be substituted by other residues, while still retaining more than 1% activity of the wild-type enzyme. We compared the kinetics and determined the crystal structures of dUMP complexes of three of the most active, uncharged single mutants of these arginines, R23I, R178T, and R179T, and of double mutants (R23I, R179T) and (R178T, R179T). The dramatically higher K(m) for R178T compared to the other two single mutants arises from the effects of R178 substitution on the orientation of dUMP; 10-15-fold increases in for R23I and R178T reflect the role of these residues in stabilizing the closed conformation of TS in ternary complexes. The free energy for productive dUMP binding, DeltaG(S), increases by at least 1 kcal/mol for each mutant, even when dUMP orientation and mobility in the crystal structure is the same as in wild-type enzyme. Thus, the four arginines do not contribute excess positive charge to the PO(4)(-2) binding site; rather, they ideally complement the charge and geometry of the phosphate moiety. More-than-additive increases in DeltaG(S) seen in the double mutants are consistent with quadratic increases in DeltaG(S) predicted for deviations from ideal electrostatic interactions and may also reflect cooperative binding of the arginines to the phosphate oxygens.

Spontaneous ECLomas in cotton rats (Sigmodon hispidus): tumours occurring in hypoacidic/hypergastrinaemic animals with normal parietal cells

We have identified cotton rats with a high female-predominant occurrence of spontaneous gastric carcinomas localized to the oxyntic mucosa, classified as malignant enterochromaffin-like (ECL) omas. The present study was made to further characterize these ECLomas and surrounding oxyntic mucosa, both morphologically using histochemical and immunohistochemical methods, and for gene expression by northern blot analysis. Among eight female cotton rats, three had an irregularly thickened oxyntic mucosa, increased stomach weight and a high serum gastrin level. Histopathological examination showed adenomatous hyperplasia of the thickened oxyntic mucosa with areas of an invasive neoplastic tumour. Immunohistochemistry, using the general neuroendocrine cell marker chromogranin A (CgA) and the specific ECL cell marker histidine decarboxylase (HDC), showed a considerably increased ECL cell density. These ECL cells displayed active proliferation, with hyperplasia, dysplasia and neoplasia. Parietal cells were not found in the tumour tissue. Parietal cell density was only slightly reduced in the surrounding oxyntic mucosa. The antral mucosa was histopathologically normal with a normal number of gastrin-immunoreactive cells. Likewise, somatostatin-immunoreactive cells did not show any differences in the antral and oxyntic mucosa between rats with pathological and normal oxyntic mucosa. Northern blot analysis revealed increased expression of CgA and HDC mRNA in the thickened oxyntic mucosa, whereas H(+)/K(+) ATPase mRNA was similar in the oxyntic mucosa of those with thickened and normal oxyntic mucosa. Gastrin mRNA in the antral mucosa was high in animals with thickened oxyntic mucosa. Somatostatin mRNA expression was similar in the antral mucosa of control animals and animals with a thickened oxyntic mucosa. We conclude that the spontaneous gastric carcinoma occurring in female cotton rats is an ECLoma developing secondary to hypergastrinaemia due to reduced intragastric pH. The mechanism for reduced acidity is not known, but is not gastric atrophy.

A new model of white matter injury in neonatal rats with bilateral carotid artery occlusion

Periventricular leukomalacia is an important cause of cerebral palsy and characterized by cysts and coagulation necrosis in the periventricular white matter. Since no model of periventricular leukomalacia has been established in small animals, it is expected to establish a new model of white matter injury in immature rodents. Bilateral carotid arteries were occluded in neonatal rats at 5 days of age, and the brain neuropathologically examined at 7 days of age. Among 22 brains histologically examined, 20 (90.9%) had white matter changes including coagulation necrosis and cystic lesions in and around the internal capsule, while only two had small cerebral infarction and five showed some ischemic neurons in the cerebral cortex. Cerebral blood flow (CBF) decreased to about 25% of controls in the subcortical white matter in the animals with bilateral carotid artery occlusion (BCAO). Amyloid precursor protein (APP) immunohistochemistry demonstrated various APP-immunoreactive axonal profiles in the internal capsule and the subcortical white matter, and stronger expression of APP in pyramidal neurons in the cerebral cortex of BCAO brains. These results indicated that the white matter is more vulnerable than the cerebral cortex in 5-day-old rats when CBF decreases to about 25% and suggested that this model is useful for investigating the white matter changes induced by cerebral hypoperfusion in the neonatal brain, since previous models of hypoxic-ischemic brain injury in neonatal mice and rats revealed preferential susceptibility of the gray matter. It was also indicated that APP is a sensitive marker for mild axonal disruption in the white matter of the immature brain.

Monoclonal antibodies specific to carbohydrates of Echinococcus multilocularis

To investigate the complexity of epitopes presented on Echinococcus multilocularis (E.m.) metacestode carbohydrates, a panel of monoclonal antibodies (MoAbs) was generated and characterized. Thirty of the clones were obtained and classified into three types (types I to III) based on Western blotting (WB) and dot-ELISA. One MoAb (type I) appeared to react with one of the carbohydrate antigens (C-antigens) located at 30-35 kDa, and was the most effective diagnostic antigen for human alveolar hydatid disease (AHD) in Hokkaido, Japan. The second group (15 clones) of MoAb (type II) reacted with another C-antigen; one which also induced antibody response in AHD patients. The third group (14 clones) of MoAb (type III) reacted with other C-antigens both in ELISA and dot-ELISA, but did not react in WB. Cross-reaction to the antigens of Echinococcus granulosus was faintly observed in only the type I-MoAb by dot-ELISA. In the immunohistological studies, all of the MoAbs reacted strongly with the laminated layer though not with protoscoleces in metacestode tissue prepared from experimentally infected cotton rats. Tissue sections treated with sodium periodate lost their immunoreactivity, suggesting that these MoAbs recognized carbohydrate epitopes of the E.m. metacestode.

Recent epidemiologic trends in alveolar echinococcosis prevalence in humans and animals in Hokkaido

We investigated chronological and geographical changes of alveolar echinococcosis (AE) prevalence in 14 administrative districts of Hokkaido based on the data of our epizootiologic and seroepidemiologic surveys. The results suggest that the chronological transitions of the enzootic state of AE in Hokkaido markedly reflect those of human AE prevalence, and that new prevalence of human AE has been emerging from central and western Hokkaido.

Neuroendocrine (ECL cell) differentiation of spontaneous gastric carcinomas of cotton rats (Sigmodon hispidus)

BACKGROUND AND PURPOSE

Female inbred cotton rats develop adenocarcinomas in the oxyntic mucosa. Since a female preponderance is typical for enterochromaffin-like (ECL) cell tumors, we examined such tumors for ECL cells. Gastrin plays a decisive role in ECL cell tumorigenesis, so blood gastrin concentration and gastric mucosal pH were measured.

METHODS

The stomachs from six female cotton rats (6 to 8 months old) were studied histologically, and at euthanasia, gastric mucosal pH was determined. Euthanasia was performed on 15 other female cotton rats of similar age for determination of blood gastrin values by radioimmunoassay (RIA) and gastric mucosal pH. Rats were classified macroscopically to have normal or thick oxyntic mucosa, with or without tumor.

RESULTS

Among the six cotton rats studied histologically, two 6-month-old rats had normal and two others had thick gastric mucosa, whereas two 8-month-old rats had thick mucosa with tumors. The ECL cells were markedly hyperplastic in all rats with thick mucosa, and ECL cells were found in the neoplastic parenchyma. All cotton rats with normal-appearing gastric mucosa had pH <2.5, whereas 14 rats with thick mucosa had pH >3.1 and hypergastrinemia.

CONCLUSIONS

Gastrin may play a major role in ECL cell hyperplasia and, perhaps, in adenocarcinoma genesis.

Identification of major wheat allergens by means of the Escherichia coli expression system

Wheat proteins were fractionated into salt-soluble, glutenin-rich, and gliadin-rich fractions. Reactivities of these protein fractions with sera of patients with wheat-associated allergies were examined under various conditions. The relative reactivity of the fractions was generally in the order glutenin-rich > gliadin-rich >> salt-soluble fractions, although their reactivities were variable among patients and among the reaction conditions, indicating that the kind, the number and the epitope of allergens were variable among patients. To identify major allergens, alpha-, gamma- and omega-gliadin, and low-molecular-mass (LMM)- and high-molecular-mass (HMM)-glutenin genes were expressed in Escherichia coli by means of a pET vector. Recombinant gliadins and glutenins were partially purified on the basis of the solubilities of prolamin and glutelin. The partially purified recombinant proteins were reacted with the patients' sera. LMM glutenin containing many Gln-Gln-Gln-Pro-Pro motifs, which was identified to be IgE-binding epitope [Tanabe, S., Arai, S., Yanagihara, Y., Mita, H., Takahashi, K. & Watanabe, M. (1996) Biochem. Biophys. Res. Commun. 219, 290-293], exhibited the highest reactivity. The next highest reactivities were observed on alpha-gliadin and gamma-gliadin, which had not been identified as allergens.

Analysis of wool fiber by alkali-catalyzed pyrolysis gas chromatography

Alkali-catalyzed pyrolysis gas chromatography (PyGC) has been used to identify minute samples of wool fiber. The wool sample to which aqueous sodium hydroxide was added was pyrolyzed in a Curie-point pyrolyzer attached to a gas chromatograph or a gas chromatograph-mass spectrometer. The addition of an aqueous solution of sodium hydroxide increased the production of specific volatile pyrolysis products from the constitutive amino acid residues of wool protein, i.e. acetaldehyde from alanine or proline, isobutyronitrile from valine, 2-methylbutyronitrile from isoleucine, isovaleronitrile from leucine and toluene from phenylalanine. Compared with conventional non-catalyzed PyGC, the alkali-catalyzed PyGC was found to greatly improve the detection limit of wool fiber and make it possible to analyze very minute samples. The alkali-catalyzed PyGC presented here has been shown to be applicable to minute thermally-denatured samples of wool fiber which cannot be identified successfully by morphological inspection using a microscope or by using Fourier-transform infrared microspectroscopy. Furthermore, the present PyGC method was successfully used for several protein samples and was shown to be useful for analysis of proteins other than wool fibers by using different special pyrograms reflecting different amino acid compositions.

Motor nerve conduction studies on children with spinal muscular atrophy

Median and posterior tibial motor nerve conduction studies were performed on 10 children with spinal muscular atrophy (SMA). Three patients with SMA type I, in whom rapid deterioration occurred, showed reduced motor nerve conduction velocity and a remarkably low M-wave amplitude in both nerves. In type II and III patients, the motor nerve conduction velocity was normal in the median nerve, although the M-wave amplitude was small in the tibial nerve. In four patients, a reduction of the M-wave amplitude was observed as clinical symptoms advanced. These findings may suggest that motor conduction studies in spinal muscular atrophy provide complementary information for understanding the pathogenesis and are also useful to clarify the heterogeneity of this disease.

Spinal cord MRI in neuro-Behçet's disease

We report the case of a 10-year-old boy with neuro-Behçet's disease. Spinal cord MRI showed signal abnormalities in the cervical and thoracic cord, but cerebral CT and MRI revealed no abnormality.

[Gas chromatographic analysis of reduction products of paraquat, diquat and the related compounds: reductive cleavage in the pyridine ring on N-alkylpyridinium derivatives with NaBH4-NiCl2 reduction system, and inhibition of the cleavage]

When N-alkylpyridinium derivatives were reduced with sodium borohydride-nickel (II) chloride reduction system, reductive cleavage occurred at the C-N bond in the pyridine ring of N-alkylpyridinium derivatives to give a small amount of reductive cleavage product along with the major perhydrogenated product. It was presumed in the previous report that this reductive cleavage in the pyridine ring proceeded through a complex of nickel ion and 1,2,3,6-tetrahydropyridine derivatives produced with NaBH4 alone reduction. The abundances of these reductive cleavage products arising from N-alkylpyridinium derivatives, i.e., paraquat, diquat and so on, are capable of giving a bad effect on the accuracy of gas chromatographic analysis. For the purpose of inhibition of the reductive cleavage in this reduction system, a suitable catalyst was examined. In addition, we pursued whether borane-1,2,3,6-tetrahydropyridine derivative complexes arose from N-alkylpyridinium derivatives by NaBH4 alone reduction or not, and whether these borane-amine complexes were the precursors of reductive cleavage products or not. N-Alkyl-1,2,3,6-tetrahydropyridine derivatives (III-I, IV-I, VI-I, VII-I and VIII-I) and the corresponding borane-amine complexes (III-II, IV-II, VI-II, VII-II and VIII-II) were synthesized by NaBH4 reduction in aqueous solution of N-alkylpyridinium salts, i.e. I, II, 1,4-dimethylpyridinium iodide (III), 1-dodecylpyridinium chloride (IV), 1,1'-diethyl-4,4'-dipyridinium dichloride (V), 1-methyl-4-phenylpyridinium iodide (VI), 1-n-propylpyridinium iodide (VII) and 1-n-butylpyridinium iodide (VIII). The structure of the borane-amine complexes were proved by the Mass spectrometry and 1H- and 13C-NMR analysis. The NiCl2-NaBH4 reduction of the borane-amine complexes gave the perhydrogenated products alone, but not reductive cleavage products. In conclusion, it was recognized that the precursors of reductive cleavage products were not borane-amine complexes, but 1,2,3,6-tetrahydropyridine. Furthermore, it was found the reductive cleavage at the C-N bond in the pyridine ring of these 1,2,3,6-tetrahydropyridine derivatives was hindered by applying Amberlite-Ni2B, NaBH4 reduction system.

Female-predominant occurrence of spontaneous gastric adenocarcinoma in cotton rats

In a colony of cotton rats (Sigmodon hispidus) consisting of 258 female and 283 male animals, 61 females and 2 males had a gastric mucosal lesion. This lesion developed in rats over 2 months of age, with a gradual increase in incidence thereafter. The lesion was grossly characterized by diffuse, often irregular thickening of the fundic mucosa, but the antrum was not affected. In 46% of the rats with this lesion, the serosal surface of the stomach was also involved. There was no evidence of disseminating or blood-borne metastasis. Histologically the mucosal thickening indicated a monotonous, diffuse proliferation of gastric glands with slight nuclear atypia, interpreted to be adenomatous hyperplasia. Invasion into submucosal, muscular, and subserosal layers by neoplastic cells with more atypia than the adenomatous hyperplasia was also noted and interpreted to be a tubular adenocarcinoma. In the adenocarcinoma lesions the infiltrating glands were surrounded by a desmoplastic reaction. In several of the adenocarcinoma lesions there were poorly differentiated adenocarcinoma cells with distorted gland formation. Lesions were diagnosed by soft X-ray examination with barium, without the need for laparotomy. Because these combined data demonstrate the spontaneous occurrence of gastric adenocarcinoma in the background of adenomatous hyperplasia, this cotton rat model can be used to examine, in minute detail, multistep carcinogenesis in the digestive tract.