Neural precursor cells derived from human embryonic brain retain regional specificity

Recent studies have revealed that neural precursor cells can be expanded not only from the subventricular zone and hippocampus but also from other regions of the human embryonic brain. To determine the regional differences of these precursor cells, we divided the brain of a 9-week-old human embryo into four parts, i.e., telencephalon, diencephalon, mesencephalon, and rhombencephalon. All cultures of the tissues yielded neurospheres, and these spheres gave rise to neurons, astrocytes, and oligodendrocytes. An analysis of clonal populations revealed that these precursor cells were multipotent, and two region-specific differences in neural precursor cells were revealed: 1) The precursor cells from the rostral part of the brain tended to proliferate faster than those from the caudal part, and 2) the precursor cells from the diencephalon and mesencephalon gave rise to more tyrosine hydoxylase (TH)-positive neurons than those from the telencephalon and rhombencephalon. When 50-day-cultured spheres were caused to differentiate, the percentage of TH-positive cells per total cell population was 1.2% for diencephalic and mesencephalic precursors, whereas it was 0.4% for telencephalic and rhombencephalic ones. Furthermore, the TH-positive cells from diencephalic and mesencephalic precursors were large, multipolar, and gamma-aminobutyric acid (GABA)-negative, which suggested that these cells were midbrain dopaminergic neurons. In contrast, TH-positive cells from telencephalic and rhombencephalic precursors were small, bipolar, and GABA-positive. These results suggest that human neural precursor cells might have the potential to differentiate into a variety of cells but retain regional specificity.     

Independent inputs by VGLUT2- and VGLUT3-positive glutamatergic terminals onto rat sympathetic preganglionic neurons

To characterize glutamatergic axon terminals onto sympathetic preganglionic neurons (SPNs), we visualized immunohistochemically three vesicular glutamate transporters (VGLUTs) in the intermediolateral cell column (IML) of rat thoracic spinal cord. VGLUT2 and VGLUT3 immunoreactivities but not VGLUT1 immunoreactivity were distributed in the IML and found in terminals making asymmetric synapses and apposed to dendrites immunopositive for choline acetyltransferase, an SPN marker. VGLUT2 and VGLUT3 immunoreactivities were not co-localized with each other. A population of VGLUT2-immunoreactive but not VGLUT3-immunoreactive terminals were adrenergic or noradrenergic. Some of VGLUT3-immunoreactive but not VGLUT2-immunoreactive terminals contained serotonin. These results indicate at least two independent glutamatergic terminal populations, which include a distinct monoaminergic subpopulation, making excitatory inputs onto SPNs.     

A novel animal model of acute cochlear mitochondrial dysfunction

Acute mitochondrial dysfunction in the cochlea is likely to result in hearing loss as a consequence of local energy shortage, similar to ischemia- or noise-induced hearing loss. To establish an animal model of acute cochlear mitochondrial dysfunction, we applied a mitochondrial toxin, 3-nitropropionic acid (3-NP) in the rat cochlea. Rats treated with 500mM 3-NP exhibited permanent threshold shifts in acoustic brainstem response while the same volume of 300mM 3-NP caused temporary threshold shifts. Histological examination in the permanent threshold shift model revealed severe degeneration of fibrocytes within spiral ligament and spiral limbus, indicating these cells are vulnerable to acute mitochondrial dysfunction. This model represents a novel tool for investigating the pathophysiology of acute cochlear mitochondrial dysfunction.     

Familial amyotrophic lateral sclerosis with bulbar onset and a novel Asp101Tyr Cu/Zn superoxide dismutase gene mutation

We describe a patient with familial amyotrophic lateral sclerosis (FALS) in whom we identified a novel missense mutation in exon 4 (Asp101Tyr) of the Cu/Zn superoxide dismutase (SOD1) gene. The disease started with a bulbar symptom (rapidly progressive hoarseness) and at autopsy showed degenerative changes restricted to the upper and lower motor neuron systems (more strictly, with lower motor predominance, showing the most severe degeneration in the nucleus ambiguus). Occasional intracytoplasmic Lewy-body-like hyaline inclusions that were immunoreactive for ubiquitin and SOD1, but immunonegative for neurofilament protein, were found in the lower motor neurons. This is the first report of hoarseness as the initial manifestation of FALS. This SOD1 gene mutation may be associated with a particular clinicopathological phenotype.     

Redox status of plasma coenzyme Q10 indicates elevated systemic oxidative stress in Parkinson's disease

Oxidative stress is suggested to play an important role in the pathogenesis of Parkinson's disease (PD). However, no elevation of plasma oxidative stress marker has been reported. We measured percent content of the oxidized form of coenzyme Q10 in total coenzyme Q10 (%CoQ-10) because %CoQ-10 has been shown to be a sensitive marker of oxidative stress. A slight but significant elevation in %CoQ-10 was observed in PD patients when compared with age/gender-matched normal subjects, suggesting elevated systemic oxidative stress in PD patients.     

Adult-onset leukoencephalopathy with vanishing white matter with a missense mutation in EIF2B5

We report of a woman aged 52 years born to consanguineous parents and seeking treatment for progressive dementia and delusion. Neurologic examination revealed dementia and emotional instability, indifference, and confabulation. There was also mild spasticity of the bilateral lower limbs. MRI revealed diffuse white matter hyperintensity on T2-weighted images accompanied by hypointense areas on fluid-attenuated inversion recovery images. A homozygous missense mutation was identified in EIF2B5.     

Evaluation of sympathetic skin response in patients with attention deficit/hyperactivity disorder presenting with comorbid disorders

We studied sympathetic skin response (SSR) to visual emotional stimuli in two children with attention deficit/hyperactivity disorder (AD/HD) and nine healthy controls, and correlated them with comorbid disorders. They were diagnosed as having conduct disorder at administration. Two years after interventions of medical care, counseling and education, they were improving in behavior, one with oppositional defiant disorder (ODD) and another without ODD at this study. SSR were evoked in the patient without ODD (a 10-year-old boy), but not in the patient with ODD (a 12-year-old boy). These findings indicate failure of a patient with both AD/HD and ODD to respond autonomically to social stimuli, and suggest association between emotional signal and empathy.     

Molecular mechanisms for activation of voltage-independent Ca2+ channels by endothelin-1/endothelin-A receptors

Endothelin-1 (ET-1) activates two types of Ca2+- permeable non-selective cation channels (designated NSCC-1 and NSCC-2) and a store-operated Ca2+ channel (SOCC) in Chinese hamster ovary cells expressing endothelin-A receptors (CHOETAR), which couple with Gq, Gs and G12. The purpose of this study was to identify the G proteins involved in the activation of these Ca channels, using mutated ETARs with coupling to either Gq or Gs/G12 (designated ETAR(Delta)385 and SerETAR, respectively) and a dominant negative mutant of G12 (G12G228A). ETAR(Delta)385 is truncated downstream of Cys385 in the C-terminal as palmitoylation sites, whereas SerET(A)R is unpalmitoylated because of substitution of all the cysteine residues to serine (CysCys --> SerSer). ET-1 activated SOCC in CHO-ET(A)R(Delta)385. In CHO-SerET(A)R or CHO-ET(A)R pretreated with U73122, an inhibitor of phospholipase C, ET-1 activated NSCC-1. ET-1 activated SOCC in CHO-ETAR microinjected with G12G228A. Moreover, ET-1 activated NSCC-1 in CHO-ETAR treated with LY 294002, the phosphoinositide 3-kinase inhibitor. These results indicate that NSCC-1 is activated via a G12-dependent pathway, NSCC-2 via Gq/phospholipase C-dependent and G12-dependent pathways, and SOCC via a Gq-phospholipase C-dependent pathway. In addition, NSCC-2 and SOCC are stimulated by ET-1 via a phosphoinositide 3-kinase-dependent cascade, whereas NSCC-1 is stimulated via a phosphoinositide 3-kinase-independent cascade.     

Associations between baseline plasma MHPG (3-methoxy-4-hydroxyphenylglycol) levels and clinical responses with respect to milnacipran versus paroxetine treatment

The purpose of this study was to investigate the effects of milnacipran and paroxetine on plasma levels of catecholamine metabolites, and we attempted to elucidate the differences between the mechanisms of these drugs in catecholaminergic neurons. In depressed patients, we investigated the relationships among pretreatment levels of catecholamine metabolites, the changes in plasma catecholamine metabolite levels before and after administration of milnacipran or paroxetine, and clinical response to these drugs. Responders to milnacipran showed lower pretreatment levels of plasma 3-methoxy-4-hydroxyphenylglycol (pMHPG) than did nonresponders to milnacipran; there was also a positive correlation between changes in pMHPG levels and percent improvement of the score on the 17-item Hamilton Rating Scale for Depression (HRSD). On the other hand, responders to paroxetine showed higher pretreatment levels of pMHPG than did nonresponders to paroxetine, and a negative correlation was observed between changes in pMHPG levels and percent improvement of the HRSD score. However, a significant difference was not observed in the pretreatment plasma level of homovanillic acid between responders and nonresponders to treatment with milnacipran or paroxetine. These results suggest that there is an association between baseline pMHPG levels and clinical responses with respect to milnacipran versus paroxetine treatment.     

alpha1-Microglobulin as a promising marker of cadmium-induced tubular dysfunction, possibly better than beta2-microglobulin

The purpose of the present study was to evaluate the validity of alpha1-microglobulin (alpha1-MG) in comparison with popularly used beta2-microglobulin (beta2-MG). A database on 8975 cases of never-smoking adult women was revisited; the data were based on spot urine samples from the women in 10 prefectures all over Japan. The validity of alpha1-MG was examined following essentially the same protocol as beta2-MG was examined in a previous study. Comparisons were made for alpha1-MG as observed (e.g. alpha1-MG(ob)), as corrected for creatinine (CR or cr) (e.g. alpha1-MGcr) and as corrected for a specific gravity (SG or sg) of 1.016 (e.g. alpha1-MGsg). A cut-off value of 5.0 mg alpha1-MG/g cr or l was deduced from 400 microg beta2-MG/g cr taking advantage of the regression equation between alpha1-MG and beta2-MG. The prevalence of alph1-microglobulinuria as corrected for a specific gravity of 1.016 (or alpha1-MGsg-uria in short) was essentially unchanged irrespective of SG, except for in very dense or very thin urine samples. alpha1-MGcr-uria prevalence decreased at higher CR. Comparison of the present observation with previous findings on beta2-MG-uria prevalence showed that the variation in prevalence of MG-uria as a function of urine density was smaller for alpha1-MGsg whereas it was substantially larger for beta2-MGcr, and thus it appeared prudent to consider alpha1-MGsg rather than beta2-MGcr as a marker of tubular dysfunction.