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Tohru Hoshida

Publications and source records attributed to Tohru Hoshida.

10 recordsLinked to original sources
PubMed2006

Imaging steps of lymphatic metastasis reveals that vascular endothelial growth factor-C increases metastasis by increasing delivery of cancer cells to lymph nodes: therapeutic implications.

Preclinical and clinical studies positively correlate the expression of vascular endothelial growth factor (VEGF)-C in tumors and the incidence of lymph node metastases. However, how VEGF-C regulates individual steps in the transport of tumor cells from the primary tumor to the draining lymph nodes is poorly understood. Here, we image and quantify these steps in tumors growing in the tip of the mouse ear using intravital microscopy of the draining lymphatic vessels and lymph node, which receives spontaneously shed tumor cells. We show that VEGF-C overexpression in cancer cells induces hyperplasia in peritumor lymphatic vessels and increases the volumetric flow rate in lymphatics at the base of the ear by 40%. The increases in lymph flow rate and peritumor lymphatic surface area enhance the rate of tumor cell delivery to lymph nodes, leading to a 200-fold increase in cancer cell accumulation in the lymph node and a 4-fold increase in lymph node metastasis. In our model, VEGF-C overexpression does not confer any survival or growth advantage on cancer cells. We also show that an anti-VEGF receptor (VEGFR)-3 antibody reduces both lymphatic hyperplasia and the delivery of tumor cells to the draining lymph node, leading to a reduction in lymph node metastasis. However, this treatment is unable to prevent the growth of tumor cells already seeded in lymph nodes. Collectively, our results indicate that VEGF-C facilitates lymphatic metastasis by increasing the delivery of cancer cells to lymph nodes and therapies directed against VEGF-C/VEGFR-3 signaling target the initial steps of lymphatic metastasis.

Animals↗
PubMed2006

[Percutaneous interventional treatment of vertebral artery stenosis with coronary stents: two case reports].

Two patients underwent percutaneous interventional treatment for vertebral artery stenosis using coronary stents. Vertebral angiography of Case 1 (78-year-old male) showed right ostial 100% obstruction and left ostial 99% stenosis. Balloon angioplasty and stent placement (Multilink 4.0 x 18 mm) were performed for the left vertebral artery. Vertebral angiography of Case 2 (64-year-old male) showed bilateral ostial severe stenoses (right 90%, left 99% + alpha). Balloon angioplasty and stent placement(Multilink 3.5 x 18 mm) were performed for the right vertebral artery. These two patients showed excellent angiographic results with no complication associated with stent placement. Vertebral artery angioplasty can be performed safely using coronary interventional equipment and techniques.

Aged↗
PubMed2005

Effects of nitrous oxide on spike activity on electrocorticogram under sevoflurane anesthesia in epileptic patients.

We sought to investigate the effects of nitrous oxide on intraoperative electrocorticogram (ECoG) spike activities in 11 patients with intractable epilepsy. Grid electrodes were placed on the brain surface, and ECoG was recorded under the following conditions: 1.5 minimal alveolar anesthetic concentration (MAC) sevoflurane without nitrous oxide and 1.5 MAC sevoflurane with 50% nitrous oxide. The number of spikes for 5 minutes and the percentage of leads with spikes of total leads measured were assessed in each condition. The median numbers (25-75th) of spikes without and with nitrous oxide were 127 (87-368) and 61 (43-247), respectively. The numbers of spikes with nitrous oxide were significantly lower than those without nitrous oxide (P<0.05). The median percentages of leads with spikes without and with nitrous oxide were 68 (25-81) and 61 (28-70), respectively, and there were no significant differences in percentages of leads with spikes between the conditions. These results indicate that nitrous oxide attenuated the frequency of spikes on ECoG in epileptic patients, although it did not affect the extent of areas with spike activity.

Adult↗
PubMed2005

The effects of sevoflurane and hyperventilation on electrocorticogram spike activity in patients with refractory epilepsy.

UNLABELLED: We investigated the effects of sevoflurane and hyperventilation on intraoperative electrocorticogram (ECoG) spike activity in 13 patients with intractable epilepsy. Grid electrodes were placed on the brain surface and ECoG was recorded under the following conditions: 1) 0.5 minimal alveolar anesthetic concentration (MAC) sevoflurane, 2) 1.5 MAC sevoflurane, and 3) 1.5 MAC sevoflurane with hyperventilation. The number of spikes per 5 min and the percentage of leads with spikes were assessed in each condition. In 4 patients with chronically implanted-subdural electrodes, the leads with seizure onset and with spikes during the interictal periods in the awake state were compared with those during sevoflurane anesthesia at 0.5 MAC and 1.5 MAC. The number of spikes and the percentage of leads with spikes were significantly more under 1.5 MAC sevoflurane anesthesia compared with those under 0.5 MAC sevoflurane (P < 0.05). The induction of hyperventilation significantly increased the number of spikes and percentage of leads with spikes (P < 0.05). With 0.5 MAC sevoflurane, the leads with spikes were similar to those at seizure onset in the awake state, whereas with 1.5 MAC sevoflurane, spikes were similar to those occurring during interictal periods in the awake state. These results indicate that sevoflurane and hyperventilation can affect the frequency and extent of ECoG spike activity in patients with intractable epilepsy. Careful attention should be paid to the concentration of sevoflurane used and ventilatory status when intraoperative EcoG is used to localize epileptic lesions. IMPLICATIONS: Electrocorticogram can be used to define the location and extent of epileptic foci during epilepsy surgery. However, electrocorticogram can be affected by anesthetic technique. The present study found that sevoflurane concentration and hyperventilation affected the frequency and the extent of electrocorticogram spike activity in epileptic patients.

Adult↗
PubMed2005

Diffusion tensor imaging in cases with visual field defect after anterior temporal lobectomy.

BACKGROUND AND PURPOSE: Visual defect due to optic radiation injury is a complication of temporal lobectomy for temporal epilepsy. To investigate whether diffusion tensor imaging can delineate the changes in optic radiations after lobectomy, we evaluated parameters on tensor images for optic radiations and correlated them with visual defect. METHODS: We examined 14 cases after temporal lobectomy. Durations after surgeries ranged from 3 weeks to 9 years. The cases were classified into three groups on the basis of the severity of visual field defect (A-C, with group C the most severe). We evaluated signals on T2-weighted images and parameters of tensor images, including fractional anisotropy (FA) and apparent diffusion coefficient (ADC), for the optic radiation in both the operated and intact side. RESULTS: On T2-weighted images, high signals in optic radiations were seen in four cases, occurring more than 4 weeks after surgery. The mean operated-to-intact side FA ratio in the optic radiation decreased according to severity of visual defect (group A, 0.88; group B, 0.89; group C, 0.73). The mean operated-to-intact side ADC ratio showed no significant difference in the overall cases. The ratio for ADC, however, tended to increase according to visual defect in cases after 10 weeks postsurgery. CONCLUSION: Optic radiation showed a decreased FA value in cases after temporal lobectomy. In later stages, ADC values tended to increase and high signal intensities on T2-weighted images were observed. The FA value can be used for evaluating Wallerian degeneration of optic radiation even in the early stages after surgery.

Adult↗
PubMed2004

Retinotopy with coordinates of lateral occipital cortex in humans.

OBJECT: The lateral occipital cortex in humans is known as the "extrastriate visual cortex." It is, however, an unexplored field of research, and the anatomical nomenclature for its surface has still not been standardized. This study was designed to investigate whether the lateral occipital cortex in humans has retinotopic representation. METHODS: Four right-handed patients with a diagnosis of intractable epilepsy from space-occupying lesions in the occipital lobe or epilepsy originating in the occipital lobe received permanently implanted subdural electrodes. Electrical cortical stimulation was applied directly applied to the brain through metal electrodes by using a biphasic stimulator. The location of each electrode was measured on a lateral skull x-ray study. Each patient considered a whiteboard with vertical and horizontal median lines. The patient was asked to look at the midpoint on the whiteboard. If a visual hallucination or illusion occurred, the patient recorded its outline, shape, color, location, and motion on white paper one tenth the size of, and with vertical and horizontal median lines similar to those on, the whiteboard. Polar angles and eccentricities of the midpoints of the phosphenes from the coordinate origin were measured on the paper. On stimulation of the lateral occipital lobe, 44 phosphenes occurred. All phosphenes were circular or dotted, with a diameter of approximately 1 cm, except one that was like a curtain in the peripheral end of the upper and lower visual fields on stimulation of the parietooccipital region. All phosphenes appeared in the visual field contralateral to the cerebral hemisphere stimulated. On stimulation of the lateral occipital lobe, 22 phosphenes moved centrifugally or toward a horizontal line. From three-dimensional scatterplots and contour maps of the polar angles and eccentricities in relation to the x-ray coordinates of the electrodes, one can infer that the lateral occipital cortex in humans has retinotopic representation. CONCLUSIONS: The authors found that phosphenes induced by electrical cortical stimulation of the lateral occipital cortex represent retinotopy. From these results one can assert that visual field representation with retinotopic relation exists in the extrastriate visual cortex.

Adult↗
PubMed2002

Gene therapy for pancreatic cancer using an adenovirus vector encoding soluble flt-1 vascular endothelial growth factor receptor.

INTRODUCTION: Vascular endothelial growth factor (VEGF) plays an important role in tumor angiogenesis. The soluble form of flt-1 VEGF receptor inhibits VEGF activity in a dominant-negative manner. AIM: This study demonstrated the regional tumor suppression effect of adenovirus-mediated soluble flt-1 in human pancreatic cancer cells. METHODOLOGY: The VEGF expression level was examined in nine cell lines. Panc-1 and PK-8 were used as lower- and higher-VEGF-producing cell lines, respectively. The in vitro proliferation of cancer cells infected with adenovirus vectors encoding soluble flt-1 (Adsflt) and control vectors (AdLacZ) was not different. To assess the in vivo tumor growth suppression, cancer cells were inoculated subcutaneously in SCID mice. Adsflt, AdLacZ, or vehicle was injected directly into the tumors. The early process of tumor angiogenesis in a dorsal skinfold chamber was monitored by intravital microscopy. RESULTS: In both Panc-1 cells and PK-8 cells, the tumor growth of the Adsflt-treated group was significantly suppressed. The microvessel density, revealed by CD31 immunostaining, was also significantly lower in the Adsflt-treated group. Apoptosis index was higher in the Adsflt group. Immunofluorescence staining revealed the expression of VEGF not only in cancer cells but also in tumor stromal cells. Wild-type cells and AdLacZ-infected cells prompted strong tumor angiogenesis, whereas Adsflt-infected cells failed to exert such an effect. CONCLUSION: These results indicate that antiangiogenic gene therapy using soluble flt-1 might be an effective approach for pancreatic cancer treatment.

Adenoviridae↗
PubMed2002

Novel intraoperative cerebral blood flow monitoring by laser-Doppler scanner.

Laser-Doppler (LD) flowmetry was used to measure tissue perfusion non-invasively and continuously during neurosurgical operations using an LD scanner. Scanning was usually completed in 20 seconds. Measurements were processed in software to provide a color-coded image of the tissue perfusion. Moreover, the measurement data, expressed in LD-units, could be used for statistical data analysis. No physical contact was necessary between the scanning device and the exposed brain tissue. The imager provided two-dimensional microvascular flow maps non-invasively and quantitatively during brain operations, and could show the CO2 reactivity in the vessels. LD scanning flowmetry is a promising intraoperative monitoring method for cerebral blood flow changes.

Adult↗
PubMed2002

[Infantile partial seizures due to temporal lesions--analysis of 4 cases].

We studied 4 cases of complex partial seizures due to temporal lesions presenting with benign partial epilepsy in infancy. None of them had neurologic abnormalities. All cases had complex partial seizures, and two had lateralizing signs. All cases had temporal lesions. One of them was detected only by fluid-attenuated inversion recovery (FLAIR) imaging. Histopathologically they were astrocytomas (grade 2 and 3), glio neuronal hamartoma and focal cortical dysplasia. The present cases suggest that patient with infantile complex partial seizures should be carefully followed up, even after the disappearance of seizures, by serial MRI examination including FLAIR imaging and by clinical observation.

Astrocytoma↗