Spontaneous healing of an isolated posterior inferior cerebellar artery dissection without stroke: a case report.

BACKGROUND: Isolated posterior inferior cerebellar artery dissections can cause subarachnoid hemorrhages or infarctions. Surgical and endovascular treatments for hemorrhagic stroke cases and medical treatments using antithrombotic agents for ischemic stroke cases have been performed, but there are very few reports on nonstroke isolated posterior inferior cerebellar artery dissections, and the treatment strategy for nonstroke cases has not been established. CASE PRESENTATION: A 48-year-old healthy male felt a severe, throbbing headache on the right side and came to our clinic on the fourth day following onset. MRI examinations revealed a right posterior inferior cerebellar artery dissection and showed no infarctions or hemorrhages. He was observed carefully with continuous monitoring of blood pressure, hydrated sufficiently, and given analgesic anti-inflammatory agents. Two weeks later, the dissected vessel's diameter grew to the maximum size, though the patient's headache rapidly improved around that day. Surgical or endovascular treatments for prevention of subarachnoid hemorrhage were recommended, but careful conservative therapy was continued in accordance with the patient's wishes. Gradually, the dissection finding improved. Four months later, MRI examinations showed his right posterior inferior cerebellar artery was almost normal in size and shape. CONCLUSIONS: This is the first detailed report on a nonstroke isolated posterior inferior cerebellar artery dissection that spontaneously occurred and healed, observed by serial high-resolution MRI examinations.

Population analysis of myelosuppression profiles using routine clinical data after the ICE (ifosfamide/carboplatin/etoposide) regimen for malignant gliomas.

We propose a simple and practical modeling approach for analysis of the data for myelosuppression after cancer chemotherapy, which can be applied when pharmacokinetic data are not available and several anticancer drugs were simultaneously administered. The model equation is based on the probability density function for the Erlang distribution. The data for cell counts of leukocytes (white blood cell, WBC), platelets (PLT), and reticulocytes (RET) obtained in routine clinical laboratory tests after the ICE (ifosfamide/carboplatin/etoposide) regimen for cancer chemotherapy were retrospectively collected from 28 patients, and a population analysis was applied. The time course profiles could be well explained by the proposed model. The individual values of the time to reach the nadir were obtained by the Bayesian method, and their medians (days) were 16.8 for WBC, 12.8 for PLT, and 8.2 for RET. Such information would be useful to determine the day of visit for outpatients especially for additional treatment to prevent side effects such as infections. The model is simple and applicable to explain the time course profiles for myelosuppression irrespective of cell types, and also practical because it requires only the data from routine clinical laboratory tests without any additional burden to patients.

Endogenous tenascin-C enhances glioblastoma invasion with reactive change of surrounding brain tissue.

Tenascin-C is an extracellular matrix glycoprotein implicated in embryogenesis, wound healing and tumor progression. We previously revealed that tenascin-C expression is correlated with the prognosis of patients with glioblastoma. However, the exact role of endogenous tenascin-C in regulation of glioblastoma proliferation and invasion remains to be established. We show here that endogenous tenascin-C facilitates glioblastoma invasion, followed by reactive change of the surrounding brain tissue. Although shRNA-mediated knockdown of endogenous tenascin-C does not affect proliferation of glioblastoma cells, it abolishes cell migration on a two-dimensional substrate and tumor invasion with brain tissue changes in a xenograft model. The tyrosine phosphorylation of focal adhesion kinase, a cytoplasmic tyrosine kinase that associates with integrins, was decreased in tenascin-C-knockdown cells. In the analysis of clinical samples, tenascin-C expression correlates with the volume of peritumoral reactive change detected by magnetic resonance imaging. Interestingly, glioblastoma cells with high tenascin-C expression infiltrate brain tissue in an autocrine manner. Our results suggest that endogenous tenascin-C contributes the invasive nature of glioblastoma and the compositional change of brain tissue, which renders tenascin-C as a prime candidate for anti-invasion therapy for glioblastoma.

Dopaminergic neurons generated from monkey embryonic stem cells function in a Parkinson primate model.

Parkinson disease (PD) is a neurodegenerative disorder characterized by loss of midbrain dopaminergic (DA) neurons. ES cells are currently the most promising donor cell source for cell-replacement therapy in PD. We previously described a strong neuralizing activity present on the surface of stromal cells, named stromal cell-derived inducing activity (SDIA). In this study, we generated neurospheres composed of neural progenitors from monkey ES cells, which are capable of producing large numbers of DA neurons. We demonstrated that FGF20, preferentially expressed in the substantia nigra, acts synergistically with FGF2 to increase the number of DA neurons in ES cell-derived neurospheres. We also analyzed the effect of transplantation of DA neurons generated from monkey ES cells into 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-treated (MPTP-treated) monkeys, a primate model for PD. Behavioral studies and functional imaging revealed that the transplanted cells functioned as DA neurons and attenuated MPTP-induced neurological symptoms.

Estrogen promotes differentiation and survival of dopaminergic neurons derived from human neural stem cells.

To investigate the effect of estrogen on neuronal differentiation, especially on dopaminergic (DA) neurons, human neural stem cells (NSCs) were differentiated in the presence of 17beta-estradiol. NSCs gave rise to tyrosine hydroxylase (TH)-positive neurons in vitro, the proportion of which was increased by 17beta-estradiol. Increase in TH-positive neurons was abrogated by an estrogen receptor (ER) antagonist, ICI182780, suggesting ERs play a role in differentiation of DA neurons. The observation that ERs were expressed in both proliferating NSCs and postmitotic DA neurons suggested that increase in TH-positive neurons was due to induction and support of DA neurons. 17beta-Estradiol also increased the number of DA neurons derived from human NSCs in vivo when the cells were grafted into mouse brains. These results support a possible role for estrogen in the transplantation of NSCs for Parkinson's disease.

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.