Live-cell imaging under centrifugation characterized the cellular force for nuclear centration in the Caenorhabditis elegans embryo.

Organelles in cells are appropriately positioned, despite crowding in the cytoplasm. However, our understanding of the force required to move large organelles, such as the nucleus, inside the cytoplasm is limited, in part owing to a lack of accurate methods for measurement. We devised a novel method to apply forces to the nucleus of living, wild-type Caenorhabditis elegans embryos to measure the force generated inside the cell. We utilized a centrifuge polarizing microscope (CPM) to apply centrifugal force and orientation-independent differential interference contrast (OI-DIC) microscopy to characterize the mass density of the nucleus and cytoplasm. The cellular forces moving the nucleus toward the cell center increased linearly at ~14 pN/µm depending on the distance from the center. The frictional coefficient was ~1,100 pN s/µm. The measured values were smaller than previously reported estimates for sea urchin embryos. The forces were consistent with the centrosome-organelle mutual pulling model for nuclear centration. Frictional coefficient was reduced when microtubules were shorter or detached from nuclei in mutant embryos, demonstrating the contribution of astral microtubules. Finally, the frictional coefficient was higher than a theoretical estimate, indicating the contribution of uncharacterized properties of the cytoplasm.

Uric acid is a major chemical constituent for the whitish coloration in the medaka leucophores.

In whitish parts of teleost skin, the coloration is attributed to a light scattering phenomenon within light-reflecting chromatophores, namely leucophores and iridophores, which contain high refractive index materials in their cytoplasmic organelles, leucosomes and light-reflecting platelets, respectively. Previous chemical examinations revealed that guanine is a major constituent of the materials in the platelets of the iridophores, while, in leucophores, the detailed chemical nature of the materials contained in the leucosomes has not been reported. Here, using liquid chromatography-tandem mass spectroscopy, we investigated the chemical features of materials eluted from scales, larvae, and single chromatophores of the medaka. Results of the liquid chromatography-tandem mass spectroscopy suggested that uric acid is a major constituent of the high refractive index materials in medaka leucophores and is a unique marker to investigate the presence of leucophores in the fish. The whitish appearance of the medaka leucophores may be attributed to the light-scattering phenomenon in leucosomes, which contain highly concentrated uric acid.

The Potentiality for Development of Multiple Dural Arteriovenous Fistulas after Ligation of the Internal Jugular Vein: A Case Report.

A 74-year-old male presented with an intracranial hemorrhage caused by multiple dural arteriovenous fistulas (DAVFs) in the left transverse sinus and right sigmoid sinus. Four months previously, the patient underwent tongue cancer removal with lymph node dissection and ligation of the right internal jugular vein. Endovascular embolization (transvenous and transarterial embolization) resulted in the complete disappearance of the fistulas. Follow-up angiography revealed new arteriovenous shunts at the superior sagittal sinus and right transverse sinus, and we treated the patient with staged transarterial embolization. Finally, venous congestion almost completely resolved and the DAVFs disappeared without any sign of recurrence. This case speculates the concept of DAVF as an acquired lesion caused by intravenous hypertension and alerts clinicians to take precautions against ligation of the internal jugular vein during a cervical operation.

Rapid integumental color changes due to novel iridophores in the chameleon sand tilefish Hoplolatilus chlupatyi.

The wavelength of the light reflected from iridophores depends on the thickness and the spacing of intracellular reflecting platelets. Here, we show that the rapid color change from blue to red of the chameleon sand tilefish Hoplolatilus chlupatyi is mediated by adrenergic stimulation of a novel type of iridophore in which reflecting platelets are concentrated selectively in the periphery of the cell, near the plasma membrane. The color changes are not only observed in vivo but also in pigment cells of isolated scales which respond to increases in K+ ion concentrations in 0.5 s and to addition of norepinephrine within 1 s. The norepinephrine effect can be blocked by addition of the alpha-adrenergic antagonist phentolamine. The results suggest that adrenergic stimulation leads to changes in reflecting platelet organization in Hoplolatilus chlupatyi iridophores and represents the major mediator of the rapid color change in this fish in vivo.

What is a vertebrate pigment cell?

On the basis of discussions emerging from a workshop and discussions at the 7th meeting of the European Society for Pigment Cell Research in Geneva in 2012, this manuscript outlines useful criteria for defining the bona fide pigment cells as a functional entity of the vertebrate body plan and differentiating them from 'pigmented' cells in general. It also proposes a nomenclature for various types of pigment cells of vertebrates.

Multilineage-differentiating stress-enduring (Muse) cells are a primary source of induced pluripotent stem cells in human fibroblasts.

The stochastic and elite models have been proposed for the mechanism of induced pluripotent stem (iPS) cell generation. In this study we report a system that supports the elite model. We previously identified multilineage-differentiating stress-enduring (Muse) cells in human dermal fibroblasts that are characterized by stress tolerance, expression of pluripotency markers, self-renewal, and the ability to differentiate into endodermal-, mesodermal-, and ectodermal-lineage cells from a single cell. They can be isolated as stage-specific embryonic antigen-3/CD105 double-positive cells. When human fibroblasts were separated into Muse and non-Muse cells and transduced with Oct3/4, Sox2, Klf4, and c-Myc, iPS cells were generated exclusively from Muse cells but not from non-Muse cells. Although some colonies were formed from non-Muse cells, they were unlike iPS cells. Furthermore, epigenetic alterations were not seen, and some of the major pluripotency markers were not expressed for the entire period during iPS cell generation. These findings were confirmed further using cells transduced with a single polycistronic virus vector encoding all four factors. The results demonstrate that in adult human fibroblasts a subset of preexisting adult stem cells whose properties are similar in some respects to those of iPS cells selectively become iPS cells, but the remaining cells make no contribution to the generation of iPS cells. Therefore this system seems to fit the elite model rather than the stochastic model.

Integumental reddish-violet coloration owing to novel dichromatic chromatophores in the teleost fish, Pseudochromis diadema.

In the reddish-violet parts of the skin of the diadema pseudochromis Pseudochromis diadema, we found novel dichromatic chromatophores with a reddish pigment and reflecting platelets. We named these novel cells 'erythro-iridophores'. In standard physiological solution, erythro-iridophores displayed two hues, red and dark violet when viewed with an optical microscope under ordinary transmission light and epi-illumination optics, respectively. Under transmission electron microscopy, however, we observed no typical red chromatosomes, i.e., erythrosomes, in the cytoplasm. High-performance thin-layer chromatography (HPTLC) analysis of the pigment eluted from the erythro-iridophores indicated that carotenoid is the main pigment generating the reddish color. Furthermore, when the irrigating medium was a K(+)-rich saline solution, the color reflected from the erythro-iridophores changed from dark violet to sky blue, but the red coloration remained. The motile activities of the erythro-iridophores may participate in the changes in the reddish-violet shades of the pseudochromis fish.

Unique multipotent cells in adult human mesenchymal cell populations.

We found adult human stem cells that can generate, from a single cell, cells with the characteristics of the three germ layers. The cells are stress-tolerant and can be isolated from cultured skin fibroblasts or bone marrow stromal cells, or directly from bone marrow aspirates. These cells can self-renew; form characteristic cell clusters in suspension culture that express a set of genes associated with pluripotency; and can differentiate into endodermal, ectodermal, and mesodermal cells both in vitro and in vivo. When transplanted into immunodeficient mice by local or i.v. injection, the cells integrated into damaged skin, muscle, or liver and differentiated into cytokeratin 14-, dystrophin-, or albumin-positive cells in the respective tissues. Furthermore, they can be efficiently isolated as SSEA-3(+) cells. Unlike authentic ES cells, their proliferation activity is not very high and they do not form teratomas in immunodeficient mouse testes. Thus, nontumorigenic stem cells with the ability to generate the multiple cell types of the three germ layers can be obtained through easily accessible adult human mesenchymal cells without introducing exogenous genes. These unique cells will be beneficial for cell-based therapy and biomedical research.

Calyculin A-induced neurite retraction is critically dependent on actomyosin activation but not on polymerization state of microtubules.

Calyculin A (CL-A), a toxin isolated from the marine sponge Discodermia calyx, is a strong inhibitor of protein phosphatase 1 (PP1) and 2A (PP2A). Although CL-A is known to induce rapid neurite retraction in developing neurons, the cytoskeletal dynamics of this retraction have remained unclear. Here, we investigated the cytoskeletal dynamics during CL-A-induced neurite retraction in cultured rat hippocampal neurons, using fluorescence microscopy as well as polarized light microscopy, which can visualize the polymerization state of the cytoskeleton in living cells. We observed that MTs were bent while maintaining their polymerization state during the neurite retraction. In addition, we also found that CL-A still induced neurite retraction when MTs were depolymerized by nocodazole or stabilized by paclitaxel. These results imply a mechanism other than depolymerization of MTs for CL-A-induced neurite retraction. Our pharmacological studies showed that blebbistatin and cytochalasin D, an inhibitor of myosin II and a depolymerizer of actin, strongly inhibited CL-A-induced neurite retraction. Based on all these findings, we propose that CL-A generates strong contractile forces by actomyosin to induce rapid neurite retraction independently from MT depolymerization.

Intracranial infiltration by recurrent scalp dermatofibrosarcoma protuberans.

Dermatofibrosarcoma protuberans (DFSP) of the scalp is a rare soft tissue sarcoma. A 22-year-old male with DFSP, who had undergone several surgical excisions and radiotherapy, presented with a mild left lower-limb paresis. An MRI scan demonstrated a huge mass extending throughout the frontoparietal convexity. A macroscopically complete removal of the mass was performed. Despite this, there were several recurrences; thereafter, the patient underwent surgery, stereotactic radiosurgery and chemotherapy. The histological findings demonstrated a DFSP that both abutted and occasionally invaded the adjacent brain cortex, while extending along the Virchow-Robin spaces. Due to the highly infiltrating characteristics of DFSP, another approach, such as the use of molecular-targeted agents, will be required to significantly improve the clinical outcome.

Calyculin-A induces cleavage in a random plane in unfertilized sea urchin eggs.

Calyculin-A (CLA), a protein phosphatase inhibitor, has been known to induce cleavage resembling normal furrowing in unfertilized sea urchin eggs. In CLA-treated eggs, actin filaments and myosin assemble to form a contractile ring-like structure in the egg cortex; however, this occurs in the absence of a mitotic spindle or asters. Here, we investigated the relationship between the plane of CLA-induced cleavage and the intrinsic animal-vegetal polar axis in sea urchin eggs. The animal-vegetal axis was established using black ink to visualize the jelly canal located at the animal pole in the jelly coat surrounding the egg. We measured the acute angle between the jelly canal axis and the cleavage plane for both fertilized eggs and CLA-treated unfertilized eggs. Although the acute angle lay within 10 degrees for most of the fertilized eggs, it varied widely for CLA-treated unfertilized eggs. Measurements of the diameter of blastomeres revealed that cleavage of fertilized eggs took place in the mid-plane of the egg, but that CLA-induced divisions were unequal. These results suggest that neither the orientation nor the location of the CLA-induced cleavage furrow is related to the animal-vegetal polar axis of the egg, even though the furrowing mechanism itself is not dissimilar to that in fertilized eggs.

Electrical preconditioning attenuates progressive necrosis and cavitation following spinal cord injury.

This study evaluates the influence of preconditioning and subsequent electrical stimulation on the formation of primary and secondary lesions following spinal cord injury in rats. The dorsal surface of the spinal cord at the T7 level was stimulated 24 h before right-side hemisection (500 Hz, 10 pulses/train, at an inter-train interval of 10 sec for 2 h). Stimulation was again administered immediately after injury and then every 24 h for 7 days. Preconditioning electrical stimulation of the spinal cord activated reactive astrocytes, then significantly attenuated edema, progressive necrosis, and cavitation, especially in the secondary cavity lesions (24 h, 1 week, and 3 weeks post-injury). Upregulation of glial fibrillary acidic protein (GFAP) and vimentin immunoreactivity, a measure of reactive astrocytic response, were increased at 1 week after injury in the rats treated with electrical stimulation. These results suggest that preconditioning with electrical stimulation prevents the formation of secondary lesions after spinal cord injury. This beneficial effect may be related to the ability of electrical stimulation to attenuate trauma-induced cellular cascades.

Long-term effects of indirect bypass surgery on collateral vessel formation in pediatric moyamoya disease.

OBJECT: The authors investigated whether revascularization surgeries in children with moyamoya disease could reduce abnormal collateral formations in the posterior circulation; long-term follow-up angiography was performed to assess status. METHODS: In six patients who underwent indirect bypass surgery in childhood, long-term follow-up angiography studies were obtained between 7 and 12 years after surgery. All six patients presented with ischemic symptoms at onset of disease between 2 and 7 years of age. Ischemic insults did not occur after surgery in any patient. In five cases, the angiographically documented stages advanced bilaterally, and in three cases the angiography revealed nearly occluded intracranial carotid arteries bilaterally. In all sides in these five cases, the collateral circulation through the grafts developed well, and collateral formation from the lenticulostriate arteries and from the anterior choroidal artery decreased according to the natural advancement of disease. There was no reduction in the collateral formations from the posterior circulation, however, in four of these five cases. CONCLUSIONS: Although the data cannot directly indicate that the patients in this study remain at potential risk of developing hemorrhage in the future, these facts should be considered when evaluating the efficacy of revascularization surgeries, because the hemorrhagic potential of abnormally dilated collateral vessels from the posterior circulation would increase as the advancement of the disease.

Solitary metastasis of prostatic cancer to the internal auditory canal.

We report a 56-year-old man with a metastatic prostatic tumor who developed left orbital meatus syndrome as the first manifestation. Magnetic resonance imaging (MRI) showed a swollen lesion in the left internal auditory canal that was isointense on T1-weighted images, hyperintense on T2-weighted images, and marked by enhanced after the administration of gadolinium. A biopsy of the affected lesion confirmed the prostatic origin of the metastasis.

TGF-alpha overexpression induces astrocytic hypertrophy after cortical stab wound injury.

To determine the exact role of TGF-alpha in glial activation after traumatic brain injury, we investigated the astroglial and microglial responses after cortical stab wound injury in TGF-alpha overexpressing mice. Adult male B6D2-TgN (MMTVTGFA) 29RjC transgenic mice were used for the subjects. This transgenic line carries a TGF-alpha cDNA under the control of the dexamethasone-inducible MMTV promoter. Thus, exogenous administration of dexamethasone induces TGF-alpha overexpression. Male B6D2F1/J mice at the same age served as wild-type animals. After the cortical stab wound injury, expression of glial fibrillary acidic protein, CD-11b and interleukine-6 were investigated immunohistochemically. The results indicate that TGF-alpha might affect astrocytic hypertrophy without affecting microgliosis not only in the normal condition, but also in the pathological condition. Moreover, overexpression of TGF-alpha induced obvious expression of IL-6 around the lesion. This fact might indicate possible role of TGF-alpha in affecting neuronal function.

Hamartoma in the internal auditory canal.

An 11 year old girl presented with hearing loss in her left ear and left trigeminal and facial nerve palsy. Radiological examinations revealed an enlargement of the left internal acoustic canal and the existence of a mass protruding from the canal into the cerebellopontine angle. The partial resection of the mass by a suboccipital craniectomy resulted in ceasing the progression of her symptoms. Histological diagnosis was hamartoma with cerebellar heterotopia. The concurrence of heterotopic cerebellar tissue could help to understand the pathogenesis of hamartomas.

Both MK801 and NBQX reduce the neuronal damage after impact-acceleration brain injury.

To understand the pathogenesis of diffuse axonal injury, we investigated the temporal and spatial profiles of neuronal degeneration in impact-acceleration injury in rats using Fluoro-Jade (FJ) staining. Impact-acceleration injury was produced in Wistar rats by the method described by Marmarou et al. with some modifications. Animals were sacrificed 1, 2, 7, 14, or 28 days after injury. Paraffin-embedded coronal sections were stained with HE or FJ, or analyzed immunohistochemically for GFAP or amyloid precursor protein (APP). FJ-positive degenerative neurons were found primarily in the dorsal brainstem and thalamus from 1 to 2 days following injury and these were associated with GFAP expression. However, FJ-positive cells were rarely found after 7 days. In all rats, significant expression of APP was observed primarily in the cingulum, cerebral peduncle and pontomedullary junction. FJ also stained these injured axons. Intrathecal administration of both NMDA and AMPA/kinate glutamate receptor antagonists MK-801 and NBQX, respectively, reduced the neuronal injury. NBQX showed more significant effects on axonal injury than MK-801. These observations indicate that not only axonal damage, but also primary neuronal damage occurs in this impact-acceleration injury model. It is also suggested that NBQX can act both directly on neuronal cells and white matter and that NMDA could have a significant protective effect against not only neuronal, but also axonal injury.

Stereotactic radiosurgery for aggressive papillary tumor of the temporal bone: case report.

BACKGROUND: Papillary tumors of the temporal bone are very rare neoplasms that show locally aggressive behavior though they have low-grade histologic features. The best treatment for these tumors is a radical resection. However, if the tumor is very large, local invasiveness and hypervascularity can prevent surgeons from achieving a complete resection. As an additional treatment for the residual tumor, it remains controversial whether radiation therapy has any role. CASE DESCRIPTION: The authors describe a 53-year-old woman who suffered from left-sided tinnitus, hearing loss, and diplopia due to a large aggressive papillary tumor of the temporal bone. Radiosurgery was very effective for the tumor, which had regrown a few years after conventional radiation therapy and chemotherapy. CONCLUSIONS: The authors conclude that radiosurgery should be considered as an option for the treatment of aggressive papillary tumor of the temporal bone.