Paramagnetic artifact and safety criteria for human brain mapping

Biological effects of magnetic field and their safety criteria, especially effects of gradient magnetic field on the cerebral and pulmonary circulation during functional brain mapping are still unclear. Here we estimated that magnetically induced artifacts for the blood oxygenation level- and flow- based functional magnetic resonance imaging are less than 0.1%, and disturbance in the pulmonary circulation is less than 1.3% even if the field strength of magnetic resonance system is risen up to 10 tesla. These paramagnetic effects are considered to be small and harmless during human brain mapping

Regulation of oxygen transport during brain activation: stimulus-induced hemodynamic responses in human and animal cortices

BACKGROUND: The correlation between regional changes in neuronal activity and changes in hemodynamics is a major issue for noninvasive neuroimaging techniques such as functional magnetic resonance imaging (fMRI) and near-infrared optical imaging (NIOI). A tight coupling of these changes has been assumed to elucidate brain function from data obtained with those techniques. In the present study, we investigated the relationship between neuronal activity and hemodynamic responses in the occipital cortex of humans during visual stimulation and in the somatosensory cortex of rats during peripheral nerve stimulation. METHODS: The temporal frequency dependence of macroscopic hemodynamic responses on visual stimuli was investigated in the occipital cortex of humans by simultaneous measurements made using fMRI and NIOI. The stimulus-intensity dependence of both microscopic hemodynamic changes and changes in neuronal activity in response to peripheral nerve stimulation was investigated in animal models by analyzing membrane potential (fluorescence), hemodynamic parameters (visible spectra and laser-Doppler flowmetry), and vessel diameter (image analyzer). RESULTS: Above a certain level of stimulus-intensity, increases in regional cerebral blood flow (rCBF) were accompanied by a decrease in regional cerebral blood volume (rCBV), i.e., dissociation of rCBF and rCBV responses occurred in both the human and animal experiments. Furthermore, the animal experiments revealed that the distribution of increased rCBF and O(2 )spread well beyond the area of neuronal activation, and that the increases showed saturation in the activated area. CONCLUSIONS: These results suggest that above a certain level of neuronal activity, a regulatory mechanism between regional cerebral blood flow (rCBF) and rCBV acts to prevent excess O(2 )inflow into the focally activated area

Flow Cytometric Assessment of Neutrophil Oxidative Metabolism in Chronic Granulomatous Disease on Small Quantities of Whole Blood: Heterogeneity in Female Patients

A rapid and sensitive flow cytometric assay is presented for the quantitative estimation of the oxidative metabolic activity of individual polymorphonuclear leukocytes (PMN) on less than 100 td of whole blood. This procedure is a simplified version using whole blood of the method of Bass et al (J. Immunol. 130:1910, 1983) that estimated the metabolic burst activity of phorbol myristate acetate (PMA)-stimulated individual PMN as the intracellular generation of a fluorescence product by a flow cytometric assay. With this method, almost all the PMN from normal subjects responded to PMA as a single cell population generating bright intracellular fluorescence. PMN from a boy with chronic granulomatous disease (CGD), could not respond to PMA with any increase of their fluorescence intensity. His mother had two distinct PMN populations one functionally normal and the other defective, indicating a random lyonization in the carrier mother and the X-linked recessive mode of inheritance. In two female patients with CGD from unrelated families, their PMN responded to PMA, as a whole, with a minimal increase in the fluorescence intensity, but the metabolic defects in their PMN were not so complete as seen in a classical X-linked CGD boy. But, PMN from two female sibling patients from the other family responded to PMA as a single uniform cell population with a weak but definite fluorescence intensity. However, the genetic background of these female patients with CGD remains unclear, since PMN dysfunction could not be identified in their mothers with this method.This work was supported in part by a grant (No. 58440046) from the Ministry of Education of Japan

The Runx1 Transcription Factor Inhibits the Differentiation of Naive CD4+ T Cells into the Th2 Lineage by Repressing GATA3 Expression

Differentiation of naive CD4+ T cells into helper T (Th) cells is controlled by a combination of several transcriptional factors. In this study, we examined the functional role of the Runx1 transcription factor in Th cell differentiation. Naive T cells from transgenic mice expressing a dominant interfering form of Runx1 exhibited enhanced interleukin 4 production and efficient Th2 differentiation. In contrast, transduction of Runx1 into wild-type T cells caused a complete attenuation of Th2 differentiation and was accompanied by the cessation of GATA3 expression. Furthermore, endogenous expression of Runx1 in naive T cells declined after T cell receptor stimulation, at the same time that expression of GATA3 increased. We conclude that Runx1 plays a novel role as a negative regulator of GATA3 expression, thereby inhibiting the Th2 cell differentiation

Antitumor effects of α-bisabolol against pancreatic cancer.

In the present study, we investigated whether α-bisabolol, a sesquiterpene alcohol present in essential oils derived from a variety of plants, has antitumor effects against pancreatic cancer. α-Bisabolol induced a decrease in cell proliferation and viability in pancreatic cancer cell lines (KLM1, KP4, Panc1, MIA Paca2), but not in pancreatic epithelial cells (ACBRI515). α-Bisabolol treatment induced apoptosis and suppressed Akt activation in pancreatic cancer cell lines. Furthermore, α-bisabolol treatment induced the overexpression of early growth response-1 (EGR1), whereas EGR1 siRNA decreased the α-bisabolol-induced cell death of KLM1 cells. Tumor growth in both subcutaneous and peritoneal xenograft nude mouse models was significantly inhibited by intragastric administration of 1000 mg/kg of α-bisabolol, once a week for three weeks. The results indicate that α-bisabolol could be a novel therapeutic option for the treatment of pancreatic cancer

Glucose Metabolism in Cataractous Lens

Since the sorbitol pathway in the lens of a diabetic rat was discovered, the relation between cataract formation and aldose reductase has been studied. We measured glucose, sorbitol and fructose in the human cataractous lens by the gaschromatography. Additionally, we measured sugar and polyols in bovine, pig and rabbit lens. The ratio of sorbitol/glucose is high in rabbit, pig and bovine lens in order. In the human cataractous lens, glucose is increased in accordance with development of cataract. On the other hand, sorbitol content is high in the diabetic lens and low in the senile cataractous lens. The aldose reductase inhibitor may have beneficial effects in the prevention of diabetic cataract formation, but have not the therapeutic effect in the senile cataract

Effects of low-intensity pulsed ultrasound on osteoclasts: Analysis with goldfish scales as a model of bone

The effects of low-intensity pulsed ultrasound (LIPUS) on osteoclastogenesis were examined using fish scales that had both osteoclasts and osteoblasts. The binding of the receptor activator of NF-κB ligand (RANKL) in osteoblasts to the receptor activator of NF-κB (RANK) in osteoclasts induced osteoclastogenesis. Therefore, we focused on RANK/RANKL signaling. After 6 h of incubation following LIPUS treatment, mRNA expression of RANKL increased significantly. Resulting from the increased RANKL mRNA level, the expression of transcription-regulating factors significantly increased after 6 h of incubation, and then the mRNA expression of functional genes was significantly up-regulated after 12 h of incubation. However, the mRNA expression of osteoprotegerin (OPG), which is known as an osteoclastogenesis inhibitory factor, also significantly increased after 6 h of incubation and tended to further increase after 12 h of incubation. At 24 h of incubation, osteoclastic functional genes’ mRNA expression decreased to the level of the control. Furthermore, we performed an in vivo experiment with goldfish. Two weeks after daily LIPUS exposure, osteoclastic marker enzymes tended to decrease while osteoblastic marker enzymes were activated. The regeneration rate of the LIPUS-treated scales was significantly higher than that of the control scales. Thus, LIPUS moderately activates osteoclasts and induces bone formation. © 2017 Biomedical Research Foundation. All rights reserved