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The lateral line system and its innervation were examined in the masu salmon Oncorhynchus masou masou. The species has 8 cephalic canals (supraorbital, infraorbital, otic, preopercular, mandibular, postotic, supratemporal, and temporal portion of trunk), 1 trunk canal and 9 superficial neuromast groups (rostral, nostril, preinfraorbital, postocular, cheek and supratemporal groups in the cephalic groups, and predorsal, trunk accessory and caudal fin groups in the trunk groups). The components are generally similar to those in many other teleosts, the lateral line system of O. m. masou is distinctive in having a preinfraorbital superficial neuromast group and lacking infraorbital, mandibular and opercular superficial neuromast groups. The lateral line system of O. m. masou is compared with some other species of Oncorhynchus.

Predator–prey interactions must be considered when aiming to enhance populations by releasing artificially reared individuals into natural environments. Released individuals create an abundance of prey for predators, and a basic hypothesis of predator–prey interactions suggests that predators select large prey due to the high caloric content. An alternative hypothesis is that small individuals are vulnerable to predation due to their poor predator avoidance. This study tested these hypotheses using stocked chum (Oncorhynchus keta) and masu (Oncorhynchus masou) salmon fry and piscivorous salmonids in marine and riverine habitats in Hokkaido, Japan. Stomach contents were sampled from predators, and fork length of prey fry was measured. Then, their fork length was compared with whole stocked fry (range of mean fork length (±SD): 45.8 ± 2.55 to 49.2 ± 2.76 mm) for each habitat. As a result, prey fry were ∼3%–6% smaller than whole stocked fry, even under a prey-abundant condition (i.e., just after hatchery reared salmon fry were stocked). Piscivorous salmonids pursue schooling fry, and small fry may be easily caught due to their slow speed in avoiding predators.

Many species of salmonids have been stocked into waters outside of their native range. The invasiveness and impact of these species on native species varies depending on their biological traits, and on environmental conditions, such as climate. In Japan, rainbow trout and brown trout, both listed in 100 of the world's worst invasive alien species by the International Union for Conservation of Nature, occur as non‐native species. The invasiveness of these two species is thought to be related to seasonal flooding, given flood waters can physically damage fry and prevent population establishment. Rainbow trout have successfully invaded waters in Hokkaido, northern Japan, where the likelihood of flooding is low between June and July, when their fry emerge, but successful invasions are rare in regions south of Hokkaido. Brown trout, however, have successfully invaded waters not only in Hokkaido, but also other regions. Since brown trout have a similar life history to the native white‐spotted charr and masu salmon, with fry emerging before the flood season, they are more suited to the Japanese climate than Rainbow trout. Rainbow and brown trout interact with native species in various ways, but a common outcome of these interactions is the displacement of native charr species. Legal regulations of non‐native salmonids should be based on understandings of the ecological traits of each invasive species and regional impacts on native species. Given the ongoing nature of climate change, the nature and extent of the effects of rainbow and brown trout on native species might also change.

Biotic interactions affect species distributions, and environmental factors that influence these interactions can play a key role when range shifts in response to environmental change are modelled. ...

Brown troutSalmo truttaL. lives mainly in European rivers and is also bred in hatcheries for fishery purposes. Since the end of 19th century it has been introduced in all other continents. For the present survey most of the known self-sustaining brown trout river populations in Japan have been sampled and analyzed through sequences of the entire mitochondrial DNA control region and twelve microsatellites. In Japan, brown trout are genetically not homogeneous, probably as a consequence of several introductions, one in the Azusa river and at least one other in the remaining territory. The Chuzenji hatchery houses a genetically very distinct strain, probably due to intense manipulation in isolated scientific experimentations over 30 years. Finally, most populations showed high genetic diversity (Mamachi, Kane and Odori streams, Lake Chuzenji) with the exception of the Azusa river samples. This molecular analysis clearly demonstrates a European north Atlantic origin arrived in two distinct ways.

Artificially grown native species are released into natural environments to increase biological resources or to recover threatened populations. Such stocks typically have enhanced survivability and may outcompete wild conspecifics as so-called native invaders. In addition, it is likely that the competitive effects of native invaders on native species are more intense than those of nonnative invaders. To test these hypotheses, an enclosure experiment was conducted using young-of-the-year wild and hatchery (normally grown to a relatively large size to increase survival after stocking) native masu salmon, Oncorhynchus masou, and nonnative brown trout, Salmo trutta (which attain a smaller size than masu salmon). Competitive effects between these fishes were evaluated in terms of stomach fullness and specific growth rate of the wild masu salmon. The magnitude of the relationship between stomach fullness and growth between the experimental treatments revealed a similar pattern, suggesting that competition for foraging habitat most affected their growth. Wild masu salmon were negatively affected by hatchery conspecifics, and the effects were greater than those caused by brown trout. We propose that these outcomes were caused by competitive dominance as a consequence of body size differences. In conclusion, the results support the hypothesis that size-enhanced hatchery masu salmon have the potential to function as native invaders, and the negative effects of artificial stocks on wild masu salmon could be greater than those caused by a nonnative invader.

Native species may show invasiveness toward a recipient ecosystem through increases in abundance as a result of artificial stocking events. Salmonid species are typical examples of native invaders whose abundance is increased after stocking with hatchery fish. This study evaluated the effects of hatchery chum salmon fry on sympatric wild masu salmon fry, benthic invertebrate prey, and algae, after a single stocking event in Mamachi stream, Hokkaido, northern Japan. The results suggested that the stocked hatchery chum salmon fry decreased the foraging efficiency and growth of the wild masu salmon fry through interspecific competition, and depressed the abundance of Ephemerellidae and total grazer invertebrates (Glossosomatidae, Heptageniidae, and Baetidae) through predation. Also, the hatchery chum salmon fry may increase algal biomass through depression of grazer abundance by predation (top-down effect). These results suggested that a single release of hatchery chum salmon fry into a stream may influence the recipient stream ecosystem.

The spatial scale and density-dependent effects of non-native brown trout Salmo trutta on species richness of fish assemblages were examined at 48 study sites in Mamachi Stream, a tributary of Chitose River, Hokkaido, Japan. The density of age ≥1 year S. trutta was high in the upstream side of the main stem of Mamachi Stream. Fish species richness increased with increasing area of study sites (habitat size), but the increasing magnitude of the species richness with area decreased with increasing age of ≥1 year S. trutta density. The relationships between age ≥1 year S. trutta, however, and presence-absence of each species seemed to be different among species. Species richness was also determined by location and physical environmental variables, i.e. it was high on the downstream side and in structurally complex environments.

Interspecific interactions play a key role in determining species assemblages when nonnative species are introduced. In the Chitose River system, Hokkaido, northern Japan, nonnative brown trout Salmo trutta may have replaced nonnative rainbow trout Oncorhynchus mykiss due to interspecific competition. The outcome of this competition is predicted to be influenced by the density of both species. Then, I conducted an enclosure experiment to test whether density-dependent interspecific competition between YOY (young-of-the-year) of these species may have explained the species replacement. Rainbow trout decreased their stomach contents in the high density treatment sympatry with brown trout, and growth rate of rainbow trout decreased in the high density treatments both allopatry and sympatry with brown trout. Stomach contents and growth of brown trout were not affected by competitor species (rainbow trout) or total fish density. These results imply that brown trout are competitively superior to rainbow trout. Therefore, there is the potential for the replacement of rainbow trout by brown trout through interspecific competition.

Several habitat models have been proposed to predict population size for stream fishes and to guide habitat assessment and monitoring techniques. However, most models do not incorporate the potential advantage of molecular genetic markers. We conducted a field survey and microsatellite DNA analyses to quantify the relationships among genetic diversity, census/effective population size and habitat variables in fragmented populations of white-spotted charr (Salvelinus leucomaenis). The census population size significantly increased with the stream length, the number of pools and a pool-riffle sequence index, a proxy for channel-unit habitat type complexity within reaches. Population density was correlated with the pool-riffle sequence index only. Genetic diversity and effective population size were not correlated with the habitat variables or census population size. There was a lack of isolation-by-distance population structure in the studied populations. Our results suggest that stream length and the number of pools within reaches associated with habitat complexity are the habitat variables that explain the majority of variation in population size of white-spotted charr. Our findings provide further evidence that census population size per se is a poor indicator of the inclusive genetic diversity within populations in a fragmented landscape.

In this study, evidence for interspecific interaction was provided by comparing distribution patterns of nonnative rainbow trout Onchorhynchus mykiss and brown trout Salmo trutta between the past and present in the Chitose River system, Hokkaido, northern Japan. O. mykiss was first introduced in 1920 in the Chitose River system and has since successfully established a population. Subsequently, another nonnative salmonid species, S. trutta have expanded the Chitose River system since the early 1980s. At present, S. trutta have replaced O. mykiss in the majority of the Chitose River, although O. mykiss have persisted in areas above migration barriers that prevent S. trutta expansion. In conclusion, the results of this study highlight the role of interspecific interactions between sympatric nonnative species on the establishment and persistence of populations of nonnative species.

Invasion status and impacts of nonnative brook trout (Salvelinus fontinalis) in a Hokkaido stream were investigated with field surveys and genetic analyses. Nonnative brook trout was detected in nine (41 %) of the 22 sampled reaches in three tributaries of the Sorachi River, Hokkaido, Japan. Based on the external pigmentation, twelve putative hybrids between brook trout and native white-spotted charr (Salvelinus leucomaenis) were collected in two reaches. Microsatellite and mitochondrial DNA data established that 58% of these hybrids were first-generation (F1) progenies between male brook trout and female white-spotted charr. Our results suggest potential negative impacts of nonnative brook trout on native charr populations in Hokkaido through interspecific interactions.

The microscale environment (e.g., current velocity) along the migratory route of aquatic organisms may directly affect their performance (e.g., migration speed or survival). We used minnow traps to evaluate how stocked Chum Salmon Oncorhynchus keta fry use stream velocity to optimize seaward migration. We found that fry were primarily captured at night and the number of fry collected was higher in traps with faster velocity water at the entrance to the trap. We interpreted this to mean that the fry were optimizing their migration efficiency by using faster velocity areas, which promote more rapid downstream migration. Received July 31, 2012; accepted May 1, 2013

Newborn screening studies indicate the expected high incidence of later-onset Fabry disease with silent Fabry nephropathy while, with recent improved clinical care of premature infants, children with congenital oligonephropathy caused by premature embryonal development of the kidney are thought to be increasing. However, the coexistence of Fabry nephropathy and oligonephropathy has not been reported previously. We present the case of a 13-year-old boy who was diagnosed with Fabry nephropathy accompanied with histological features of oligonephropathy. He was born as a preterm baby, and a renal biopsy was performed because of mild renal dysfunction and mild proteinuria. He had neither characteristic early symptoms nor a family history of Fabry disease. Histologic findings demonstrated diffuse global enlargement and foamy change of podocytes with markedly decreased number and enlargement of the glomeruli. Both his plasma and leukocyte α-galactosidase A (GLA) activities were markedly decreased, and the plasma globotriaosylsphingosine and urine globotriaosylceramide levels were increased. Gene analysis revealed a missense mutation, R112H, in the GLA gene, which had been reported in the later-onset phenotype of Fabry patients. He is now under treatment with enzyme replacement therapy and an angiotensin-converting enzyme inhibitor. Conclusion: This case indicated the possible co-occurrence of Fabry nephropathy and oligonephropathy. For early diagnosis and timely management, careful examinations for proteinuria and renal function, in addition to establishing an effective screening system for Fabry disease, will be necessary.

The body size of juvenile fish is often used as an index of growth rate, which in turn is influenced by local habitat conditions. We evaluated the size and origin of juvenile Chum salmon Oncorhynchus keta in the coastal areas of three regions (Atsuta, Shari, and Konbumori) of Hokkaido, northern Japan. The origin of the individuals in these communities differed between Konbumori and the other two regions. The former contained juveniles that originated from both the nearest stocked river and other rivers that were outside the area of interest. Conversely, the communities in Atsuta and Shari consisted exclusively of fish from the nearest stocked river. Moreover, the juveniles in Konbumori were larger than those in Atsuta and Shari. The results of our otolith analysis suggest that the larger size of the fish in Konbumori was due to the immigration of large individuals from natal rivers at distant locations. Thus, immigrants were likely to enlarge their body size composition in the area of interest. In summary, if the distance from a natal river is adjusted and daily growth is taken into account, body size can be used as an indicator of growth performance in coastal juvenile chum salmon.

Flow regime is one of the major determinants of establishment success for non-native aquatic organisms. Here, we examine the influence of flow variability associated with snowmelt flood on the establishment success of non-native brown trout in 10 streams in northern Japan. We regarded the presence of Age-0 brown trout as the index of the successful establishment. The emergence of Age-0 brown trout in our study region begins in May, a time that overlaps with the occurrence of snowmelt flood. The presence of Age-0 brown trout was negatively associated with flow variability, and it was also negatively associated with summer water temperature. Our results indicate that the non-native brown trout tends to establish in the streams with smaller snowmelt floods and lower summer water temperatures. Brown trout is an invasive, non-native species that is problematic all over the world, and effective management strategies for preventing their further expansion are urgently needed. This study suggests that river managers should recognise that stable streams such as spring-fed streams (i.e., low flow and summer water temperature) and flow-regulated streams, have a higher potential risk of brown trout invasion.

A knowledge of food habits is important for evaluating interspecific competition and predation between sympatric species. Data on food availability should be combined with data on food habits in this type of survey. Although food availability differs between habitats or seasons, these differences had never been considered in previous studies. We conducted year-round field surveys throughout a stream to compare the food habits of an introduced salmonid, brown trout Salmo trutta, and a native salmonid, masu salmon Oncorhynchus masou. Masu salmon did not constitute a large proportion of the diet of brown trout and vice versa. Thus, predation will likely not affect the population level of either species. The dietary overlap between brown trout and masu salmon varied depending on the presence of Gammaridae and terrestrial invertebrates; i.e., the intensity of interspecific competition for food resources may differ according to food conditions.

The mechanisms underlying successful invasions by a competitively subordinate species are poorly understood. In Japan, nonnative brown trout Salmo trutta L. have successfully invaded a number of streams that contain native masu salmon Oncorhynchus masou Brevoort, even though young of the year (YOY) brown trout are thought to be competitively subordinate to YOY masu salmon because of their smaller body size due to later emergence time. We conducted a laboratory experiment and field observations to evaluate whether ontogenetic habitat shifts could explain the success of brown trout. In a laboratory experiment, smaller YOY brown trout were competitively inferior to YOY masu salmon. Our field observations suggest that YOY masu salmon shift to deeper and faster velocity habitat before the emergence of brown trout fry. Thus, there is separation of habitat use between the two species. Taken together, our results suggest an ontogenetic niche shift by competitively dominant native masu salmon may reduce niche overlap and the opportunity for competitive interactions, and thus facilitate invasion by a nonnative brown trout.

The mechanisms by which nonnative species establish populations can be classified into two broad categories: they usurp the niches of native species through interspecific competition, or they avoid this intense interspecific competition by making use of minimal niche overlap with the native species. In this study, we considered how a nonnative salmonid species, the rainbow trout Oncorhynchus mykiss, established a population in the presence of the native salmonid species, the masu salmon O. masou, in Hokkaido, Japan. Circumstantial field evidence shows that the masu salmon exceeds the rainbow trout in abundance and suggests that these species use different types of cover habitat (rainbow trout abundance increases with increasing abundance of large woody debris aggregates, whereas masu salmon abundance increases with increasing abundance of undercut banks). These results imply that the rainbow trout established a population due to minimal niche overlap with the masu salmon, and not by competitive exclusion of the native species.

Interspecific competition is a mechanism by which native salmonids can be replaced by non-native species. According to the two-species Lotka–Volterra competition model, replacement of the native species would occur when the non-native species has a competitive advantage over the native species and interspecific competition is more intense than competition within each of the two species. However, field observations have implied that visual barriers such as woody debris may slow down the replacement by mitigating interspecific competition. Using an experimental stream with white-spotted charr ( Salvelinus leucomaenis (Pallas, 1814)) as the native species and brown trout ( Salmo trutta L., 1758) as the non-native species, this study examined aggressive actions within and between species to assess the relative intensities of interspecific and intraspecific competitons within native species and the effect of visual barriers for reducing the relative intensity. In a sympatric and no-barrier treatment where trout was the dominant species, interspecific competition occurred more intensely than intraspecific competition among native charr. However, the relative intensity of interspecific competition decreased in a sympatric and with-barrier treatment. Our results suggest that interspecific competition may contribute to the replacement of native species by more competitive, non-native species. However, restoring visual barriers is a potential method to mitigate interference interactions and may deter the replacement.

This study aimed to confirm the mitigation effect of structurally complex habitat on interspecific interference competition between native and non-native salmonid species. We evaluated the effects of habitat complexity (number and size of aggregates of large woody debris and length of undercut banks) and other habitat components that were related to the local abundance of salmonids (dimension and mean depth of pool, mean particle size, and mean current velocity) on the local abundance of native white-spotted char ( Salvelinus leucomaenis (Pallas, 1814)) in allopatry and sympatry with non-native brown trout ( Salmo trutta L., 1758). The field survey was conducted in a Japanese montane stream. The number of char in pool habitats in the allopatric area correlated positively with habitat size, i.e., pool dimension. The number of char in the sympatric area with trout was positively correlated with habitat complexity, while it was negatively correlated with number of trout. In this study, we found that structurally complex habitats might be effective in mitigating interspecific competition between native white-spotted char and non-native brown trout in a montane stream.

This study focused on longitudinal distribution patterns of native white-spotted charr and non-native brown trout in a mountainous stream in Hokkaido, Japan. Brown trout ratio, which is the proportion of brown trout in the catch of salmonids, was decreasing from downstream to upstream. Brown trout ratio correlated negatively with water temperature. Thus, our results suggested that temperature may influence the possible competition between native white-spotted charr and non-native brown trout.

N-Methyl-D-aspartate-mediated neurotoxicity is known to involve nitric oxide production and to be augmented in an environment of reactive oxygen species. We used TUNEL staining and homogenous cytosolic immunoreactivity of cytochrome c in an acute brain slice preparation to investigate the influence of edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one), a free radical scavenger, on N-methyl-D-aspartate-induced apoptosis. Cerebrocortical slices were obtained from parietal lobes of 7-day-old Sprague-Dawley rats, superfused with well-oxygenated artificial cerebrospinal fluid, and metabolically recovered. Subsequent 30-min exposures to 10 microM N-methyl-D-aspartate in treated and untreated slices were followed by 4 h of recovery superfusion with oxygenated artificial cerebrospinal fluid. Outcomes were compared for three groups of slices: "the N-methyl-D-aspartate-only group"; "the edaravone treatment group", which had 20 microM edaravone present throughout and subsequent to N-methyl-D-aspartate exposure; the "control group", in which slices were superfused only with oxygenated artificial cerebrospinal fluid. At the conclusion of recovery (t = 4 h), the percentage of TUNEL-positive cells in the edaravone treatment group (7.0+/-3.3%) was significantly reduced from the percentage for the N-methyl-D-aspartate-only group (21.9+/-4.1%), and insignificantly greater than the percentage for the control group (3.4+/-2.1%). Percentages of cytochrome c positive cells at t = 1 h were significantly increased (p < 0.01) in the N-methyl-d-aspartate-only group (30.6+/-1.9%) compared to percentages for both the control group (11.4+/-2.6%) and the edaravone treatment group (15.2+/-2.1%). Edaravone's reduction in TUNEL staining and cytochrome c release provides evidence of reactive oxygen species mechanisms and antioxidant benefits in cytochrome c-mediated apoptosis during N-methyl-D-aspartate excitotoxicity.

In salmonid species, interspecific competition has been affirmed as the major mechanism of the replacement of native species by introduced species. However, competitive interactions are variable according to various habitat components. Our study on native white-spotted charr and introduced brown trout in a small creek in southwestern Hokkaido, Japan indicates that the intensity of the interspecific competition was reduced in structurally complex habitats, areas with numerous woody debris, because the native species were able to survive in those environments. Therefore, the replacement may be inhibited in structurally complex habitat.

Genetic population structure of artificially isolated white-spotted charr (Salvelinus leucomaenis) populations before and after translocation were examined using polymorphic microsatellite loci. We released 20 migrant females of below-dam populations in the Kame and Hitozuminai rivers, Japan, into small above-dam sites of each river, and also collected juveniles (0+ fish) of the pre-translocation and the post-translocation cohorts for DNA analyses. Reduced genetic diversity, expressed as the number of alleles and expected heterozygosity, was observed in all above-dam populations before translocation relative to below-dam populations. Highly significant genetic differentiation was also found between above- and below-dam populations. After translocation, on the other hand, genetic diversity of above-dam populations was restored to the levels of below-dam populations. Differences in gene frequencies between above- and below-dam populations were not detected after translocation. These results, in turn, suggest that the translocations in our survey had an immediate effect on the restoration of genetic diversity, and that the translocated individuals strongly introgressed into above-dam populations.

Using an artificial stream, habitat use by two sympatric native salmonids in the presence and absence of introduced salmonid species was investigated experimentally. When only native white-spotted charr Salvelinus leucomaenis and masu salmon Oncorhynchus mason were sympatric, they occupied different microhabitats. In the presence of introduced brown trout Salmo trutta or rainbow trout Oncorhynchus mykiss, however, white-spotted charr and masu salmon were observed to use a similar habitat and interspecific competition between white-spotted charr and masu salmon was initiated. The study suggested that the coexistence of native salmonids was negatively affected through interspecific competition between native and introduced salmonids.

Brown trout, Salmo trutta, and rainbow trout, Oncorhynchus mykiss, have been introduced to freshwaters in Hokkaido, Japan. Today, it is recognized that these introduced salmonids have negative impacts on native salmonids such as white-spotted charr, Salvelinus leucomaenis, and masu salmon, O. masou. In particular, interspecific competition may be an important mechanism that could contribute to the exclusion for native salmonids. In this study, experimental pairwise contests were conducted to compare interference competitive ability between native and introduced salmonids. We demonstrated that brown trout were competitively superior to white-spotted charr and masu salmon whereas rainbow trout were superior to white-spotted charr. We suggest that introduced brown trout negatively impact both white-spotted charr and masu salmon, and introduced rainbow trout negatively impact white-spotted charr.

Summary: A patient with Williams syndrome, craniosynostosis, and infantile spasms is described. At age 6 months, the infant demonstrated infantile spasms and craniosynostosis and was operated on for craniosynostosis and treated with adrenocorticotropic hormone (ACTH) for the infantile spasms. ACTH completely controlled the seizures, but was halted because of the progression of ventricular hypertrophy. The seizure returned, and he was found to have elfin face, failure-to-thrive, developmental delay, and dental malformation in addition to congenital heart defects. High-resolution chromosome analysis revealed interstitial deletion of 7q11.22-q11.23. Therefore his clinical and cytogenetic diagnosis was Williams syndrome. Thyrotropin-releasing hormone (TRH) therapy reduced his seizures and improved the findings of EEG without cardiac side effects. In addition, his psychomotor development was slightly improved.

To investigate whether ethanol has direct effects on neuronal migration in the cerebral cortex, we performed a tissue culture study using embryonic rat brain with thymidine autoradiography. After we labeled progenitor cells in the ventricular zone of E16 cerebral cortex explants with [3H]thymidine, the explants were cultured for 48 h, and then distribution of labeled cells was evaluated autoradiographically. Adding 3.0 or 6.0 mg/ml ethanol to the culture medium caused significantly decreased distribution of labeled cells in the outer intermediate [control: 2.0+/-0.6% (mean+/-S.D.); 1.0 mg/ml ethanol: 2.1+/-1.5%; 3.0 mg/ml ethanol: 0. 5+/-1.5% (P

To investigate the role of the NMDA receptor on neuronal migration in the cerebral cortex, we performed a tissue culture study using embryonic rat brain. After we labeled progenitor cells in the ventricular zone of E16 cerebral cortex explants by [3H]thymidine, the explants were cultured for 48 h. Then distribution of labeled cells was evaluated autoradiographically. Blocking NMDA receptors by adding the NMDA receptor antagonist, (+)-5-methyl-10, 11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine hydrogen maleate (MK-801: 1 or 10 microM) or d(-)-2-amino-5-phosphonopentanoic acid (d-AP5: 100 microM) to the culture medium, caused significantly decreased distribution of labeled cells in the outer intermediate zone (control 14.2+/-5.5%, 1 microM MK-801 5.8+/-7.2%, 10 microM MK-801 3.6+/-1.4%, and d-AP5 8.6+/-4.0%; mean+/-S.D.). This suggests that blocking NMDA receptors inhibits neuronal migration in the cerebral cortex. Furthermore, the influence of decreased intracellular Ca2+ concentration on neuronal migration was examined by adding intracellular Ca2+ chelator, 1, 2-bis-(o-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid tetra-(acetoxymethyl)-ester (BAPTA-AM: 5 or 25 microM). This also resulted in inhibited neuronal migration. Therefore, it seems that neuronal migration in the cerebral cortex is regulated by intracellular Ca2+ concentration, which the NMDA receptor may influence.

A water-in-oil type emulsion containing oxine has been used for the discrimination of copper(II) ions and copper-humic complexes in aqueous solutions. A toluene solution containing oxine and nonionic surfactant (Span-80) was vigorously mixed with 1 mol/L HCl by ultrasonic irradiation. The resulting emulsion was added to water and dispersed by stirring as numerous small globules. Copper(II) ions were quantitatively permeated across the oil layer and incorporated in the tiny droplets of HCl, whereas copper-humic complexes remained in the sample solution. After collecting the dispersed emulsion globules, they were destroyed by heating to segregate the aqueous (HCl) and organic (toluene) phases. The copper in the aqueous phase was determined by graphite-furnace atomic absorption spectrometry (GFAAS). The analytical results agreed with those obtained by the adsorption method, where negatively charged humic complexes were selectively collected on a macroreticular anion exchanger Sephadex A-25 column. The conventional liquid-liquid extraction did not offer a chemical speciation because copper(II) ions and humic complexes were simultaneously extracted into the organic phase. The proposed emulsion method was successfully applied to the analysis of river water samples.

北海道千歳川支流の紋別川には，本流と支流にそれぞれ堰堤があり，その下流側では，在来種アメマスから外来種ブラウントラウトへの置換が報告されている。一方，堰堤上流側では，ブラウントラウトは確認されていなかった。しかし，2004 年秋から 2005 年春の間に本流の堰堤が決壊し，堰堤上流側へのブラウントラウトの侵入が確認された。今後，堰堤上流側のアメマス個体群へのブラウントラウトの影響が懸念される。

Respiring neonatal rat cerebrocortical slices were exposed for 30 min to toxic concentrations of N-methyl-D-aspartate (NMDA; 100 microM, 500 microM and 1000 microM). In situ hybridization was used to study c-fos and hsp70 mRNA before, during, and for 8 h after NMDA exposure. Cell swelling and nuclear morphology were assessed using Cresyl violet (Nissl) staining. Possible evidence for apoptosis was examined using in situ terminal transferase d-UTP nick-end labeling (TUNEL) staining and agarose-gel electrophoresis of extracted slice DNA. After NMDA administration c-fos and hsp70 mRNA expression increased, with maxima occurring, respectively, at 1 h and 4 h after NMDA exposure. When treatment with dizocilpine (MK-801; 10 microM), a non-competitive NMDA antagonist, was started before NMDA exposures, expression of both c-fos and hsp70 mRNA was decreased to values near control, indicating that activation of NMDA receptors induces both genes. Only a minority of induced cells expressed FOS protein and no HSP70 protein expression was seen. These apparent failures of translation might be related to the stress response. Histologically, 1000 microM NMDA produced substantial necrosis, with no evidence of apoptosis. Evidence for apoptosis was found at the two lower NMDA concentrations, which produced TUNEL-positive fragmented nuclei and faint ladder patterns in DNA electrophoresis. Dizocilpine pre-treatment blocked NMDA-induced necrosis and attenuated TUNEL-positive staining in slice parenchyma. TUNEL-positive staining with a different morphology was found in the injury layer, a region 50-micron thick where mechanical trauma was inflicted when slices were cut from brain. When slices received dizocilpine immediately after decapitation, TUNEL-positive staining no longer occurred in the injury layer, in agreement with previous cell culture studies that implicated NMDA receptor activation after mechanical trauma to neurons. We conclude that at the toxic doses studied, NMDA receptor activation results primarily in necrosis. However, data at low NMDA concentrations are consistent with a small amount of apoptosis.

Total body bone mineral density was measured by dual energy X-ray absorptiometry in 52 children who were very low birth weight (VLBW) infants without cerebral palsy and mental retardation (postconceptional age, from 10 mo to 6 y and 6 mo). VLBW infants in this study seemed to show compensatory acceleration of total body bone development, catching up with the control group during early childhood. However, in VLBW infants with at least one of the three factors such as total parenteral nutrition for 1 week or more, assisted ventilation for 1 week or more, or oxygen therapy for 28 d or more in their early stage after birth, adequate mineral supplementation might be especially important for long-term bone development.

In order to elucidate the molecular mechanisms underlying neuronal migration in the developing rat cerebral cortex, a novel primary tissue culture system in which neuronal migration can be evaluated was developed. Using this culture system, through autoradiographic studies we demonstrated the migration of [ 3 H]thymidine labeled cells, and also revealed that this neuronal migration was delayed by such low dose radiation as 10 cGy. In addition, an immunohistochemical study revealed that the neural cell adhesion molecule (N-CAM), was undetectable in the matrix cell layer. When anti-N-CAM monoclonal antibodies were added to the tissue culture system, the neuronal migration delay was comparable with that observed in the case of 20 cGy radiation. These results suggest that N-CAM is related to neuronal migration in the rat cerebrum and that the neuronal migration delay evoked by low dose radiation might be caused by a disorder of N-CAM present in the matrix cells.

Immunocytochemistry of diapause hormone (DH) or pheromone biosynthesis activating neuropeptide (PBAN) revealed three clusters of neurosecretory cells present on the ventral midline of the suboesophageal ganglion (SG) of the silkworm: there were 4 cells in the anterior, 6 cells in the medial, and 2 cells in the posterior cluster. Intracellular injection of Lucifer Yellow into an anterior or a medial cell revealed that the cell has a dendritic arborization at the anterior region of the SG and that it projects an axon to the corpus cardiacum (CC) via a branch of the maxillary nerve and an associated nerve of the CC (NCC-V). A dye-filled posterior cell in the larva projects bilaterally-symmetric dendritic branches to the anterior half of the SG that is to expand laterally to fuse the brain after pupation. The axon of the cell, passing through the brain, enters the NCC 3 to spread varicose terminal branches in the CC and associated nerves of the CC.