Atsuko Shinohara

Long-term oral lithium treatment attenuates motor disturbance in tauopathy model mice: implications of autophagy promotion.

Lithium, a drug used to treat bipolar disorders, has a variety of neuroprotective mechanisms including inhibition of glycogen synthase kinase-3 (GSK-3), a major tau kinase. Recently, it has been shown that, in various neurodegenerative proteinopathies, lithium could induce autophagy. To analyze how lithium is therapeutically beneficial in tauopathies, transgenic mice overexpressing human mutant tau (P301L) were treated with oral lithium chloride (LiCl) for 4 months starting at the age of 5 months. At first, we examined the effects of treatment on behavior (using a battery of behavioral tests), tau phosphorylation (by biochemical assays), and number of neurofibrillary tangles (NFTs) (by immunohistopathology). In comparison with control mice, LiCl-treated mice showed a significantly better score in the sensory motor tasks, as well as decreases in tau phosphorylation, soluble tau level, and number of NFTs. Next, we examined lithium effects on autophagy using an antibody against microtubule-associated protein 1 light chain 3 (LC3) as an autophagosome marker. The number of LC3-positive autophagosome-like puncta was increased in neurons of LiCl-treated mice. Neurons containing NFTs were completely LC3-negative, whereas LC3-positive autophagosome-like puncta contained phosphorylated-tau (p-tau). The protein level of p62 was decreased in LiCl-treated mice. These data suggested that oral long-term lithium treatment could attenuate p-tau-induced motor disturbance not only by inhibiting GSK-3 but also by enhancing autophagy in tauopathy model mice.

Blood lead at currently acceptable levels may cause preterm labour

Objectives Although occupational and environmental exposures to lead have been dramatically reduced in recent decades, adverse pregnancy outcomes have been observed at ‘acceptable’ levels of blood lead concentrations (≤10 μg/dl). Methodology Blood samples were collected from 348 singleton pregnant women, aged 16–35 years, during the first trimester of pregnancy (8–12 weeks) for lead measurement by inductively coupled plasma–mass spectrometry. Subjects were followed up and divided into two groups (preterm and full-term deliveries) according to duration of gestation. Results The average (range) and geometric means of blood lead levels were 3.8 (1.0–20.5) and 3.5 μg/dl, respectively. Blood lead level was significantly (p<0.05) higher in mothers who delivered preterm babies than in those who delivered full-term babies (mean±SD: 4.46±1.86 and 3.43±1.22 μg/dl, respectively). Logistic regression analysis demonstrated that a 1 unit increase in blood lead levels led to an increased risk of preterm birth (OR 1.41, 95% CI 1.08 to 1.84). Conclusion Adverse pregnancy outcomes may occur at blood lead concentrations below the current acceptable level.

Early pregnancy blood lead levels and the risk of premature rupture of the membranes

To clarify the effects of lead on fetal premature rupture of the membranes (PROM), blood lead concentrations were measured using inductively coupled plasma-mass spectrometry in 332 women, aged 16-35 years, during their early pregnancy period (8-12 weeks). Blood lead concentrations were significantly higher in the 36 PROM deliveries than in the 296 non-PROM deliveries (mean ± SD, 4.61 ± 2.37 and 3.69 ± 1.85 μg/dl, respectively; p<0.05). The logistic regression analysis revealed that a 1-unit increase in the logarithm of the blood lead level led to a several-fold increase in the risk of PROM (unit risk=17.98, 95% CI 1.6-198.6). Thus, it is suggested that lead can increase the risk of PROM in pregnant women with mean blood lead less than 5 μg/dl.

Osteopontin is involved in the development of acquired chemo-resistance of cisplatin in small cell lung cancer

Osteopontin (OPN) is a multi-functional cytokine involved in cell survival, migration and adhesion which is associated with tumorigenesis, progression and metastasis. However, the role of OPN in chemo-sensitivity of human lung cancer has not yet been elucidated. The purpose of this study is to investigate the role of OPN in chemo-sensitivity of lung cancer cells. We developed a stable OPN transfectant (SBC-3/OPN) and a control transfectant (SBC-3/NEO) from human small cell lung cancer cell line, SBC-3. SBC-3/OPN cells were more resistant to cisplatin than SBC-3/NEO cells. Multi-drug resistance-associated protein (MRP) does not appear to be involved in the development of acquired chemo-resistance, since MRP inhibitor did not alter chemo-sensitivity. After exposure to cisplatin, the apoptotic SBC-3/OPN cells were reduced in number compared to SBC-3/NEO cells. Treatment with cisplatin revealed that the expression of anti-apoptotic protein, bcl-2, was down-regulated in SBC-3/NEO cells, while that of SBC-3/OPN cells was not altered. In contrast, pro-apoptotic protein, bax, was not altered in both SBC-3/OPN and SBC-3/NEO cells, thus bcl-2/bax ratio was decreased in SBC-3/NEO but not altered in SBC-3/OPN cells. Activation of caspase-3 and caspase-9 was increased in SBC-3/NEO cells, but not in SBC-3/OPN cells. Our results suggest that OPN enhances chemo-resistance of cisplatin in SBC-3 cells by suppressing bcl-2 protein down-regulation, thereby blocking the caspase-9- and caspase-3-dependent cell apoptosis.

Tumor growth suppression by gadolinium-neutron capture therapy using gadolinium-entrapped liposome as gadolinium delivery agent

Neutron capture therapy (NCT) is a promising non-invasive cancer therapy approach and some recent NCT research has focused on using compounds containing gadolinium as an alternative to currently used boron-10 considering several advantages that gadolinium offers compared to those of boron. In this study, we evaluated gadolinium-entrapped liposome compound as neutron capture therapy agent by in vivo experiment on colon-26 tumor-bearing mice. Gadolinium compound were injected intravenously via tail vein and allowed to accumulate into tumor site. Tumor samples were taken for quantitative analysis by ICP-MS at 2, 12, and 24 h after gadolinium compound injection. Highest gadolinium concentration was observed at about 2 h after gadolinium compound injection with an average of 40.3 μg/g of wet tumor tissue. We performed neutron irradiation at JRR-4 reactor facility of Japan Atomic Energy Research Institute in Tokaimura with average neutron fluence of 2×10¹² n/cm². The experimental results showed that the tumor growth suppression of gadolinium-injected irradiated group was revealed until about four times higher compared to the control group, and no significant weight loss were observed after treatment suggesting low systemic toxicity of this compound. The gadolinium-entrapped liposome will become one of the candidates for Gd delivery system on NCT.

Chronic magnesium deficiency decreases tolerance to hypoxia/reoxygenation injury in mouse heart

AIMS Magnesium (Mg) deficiency has been reported to be associated with the development of the metabolic syndrome, cardiovascular diseases, and sudden death. We examined the influence of chronic Mg deficiency on cardiac tolerance to hypoxia/reoxygenation injury. MAIN METHODS Mice were fed an Mg-deficient diet for 4 weeks, and then their hearts were excised for Langendorff perfusion experiments. The levels of total Mg in the blood and heart were quantified by atomic absorption spectrometry. KEY FINDINGS In Mg-deficient mice, the Mg concentration in whole blood was markedly decreased; however, that in the heart remained unchanged. When the hearts of control mice were exposed to hypoxia/reoxygenation, removal of extracellular Mg from a normal Krebs solution containing 1.2 mM Mg resulted in a significant decrease in the recovery of the tension-rate product (TRP) upon reoxygenation. In Mg-deficient mice, the recovery of TRP in the heart was reduced significantly in the absence of extracellular Mg compared to that in controls. The addition of Mg to the perfusate did not improve TRP recovery. During hypoxia/reoxygenation, cardiac damage evaluated by myocardial aspartate amino transferase (AST) release was greater in hearts of Mg-deficient mice than in that of control mice. SIGNIFICANCE These results indicate that chronic Mg deficiency causes severe hypomagnesemia and a decrease in cardiac tolerance to hypoxia, without changing the intracellular Mg content. The decreased tolerance to hypoxia was not affected by the presence or absence of extracellular Mg, suggesting that some intracellular metabolic abnormalities develop in the cardiac myocytes of Mg-deficient mice.

Feasibility evaluation of neutron capture therapy for hepatocellular carcinoma using selective enhancement of boron accumulation in tumour with intra-arterial administration of boron-entrapped water-in-oil-in-water emulsion.

INTRODUCTION Hepatocellular carcinoma (HCC) is one of the most difficult to cure with surgery, chemotherapy, or other combinational therapies. In the treatment of HCC, only 30% patients can be operated due to complication of liver cirrhosis or multiple intrahepatic tumours. Tumour cell destruction in boron neutron-capture therapy (BNCT) is due to the nuclear reaction between (10)B atoms and thermal neutrons, so it is necessary to accumulate a sufficient quantity of (10)B atoms in tumour cells for effective tumour cell destruction by BNCT. Water-in-oil-in-water (WOW) emulsion has been used as the carrier of anti-cancer agents on intra-arterial injections in clinical. In this study, we prepared (10)BSH entrapped WOW emulsion by double emulsifying technique using iodized poppy-seed oil (IPSO), (10)BSH and surfactant, for selective intra-arterial infusion to HCC, and performed simulations of the irradiation in order to calculate the dose delivered to the patients. MATERIALS AND METHODS WOW emulsion was administrated with intra-arterial injections via proper hepatic artery on VX-2 rabbit hepatic tumour models. We simulated the irradiation of epithermal neutron and calculated the dose delivered to the tissues with JAEA computational dosimetry system (JCDS) at JRR4 reactor of Japan Atomic Research Institute, using the CT scans of a HCC patient. RESULTS AND DISCUSSIONS The (10)B concentrations in VX-2 tumour obtained by delivery with WOW emulsion were superior to those by conventional IPSO mix emulsion. According to the rabbit model, the boron concentrations (ppm) in tumour, normal liver tissue, and blood are 61.7, 4.3, and 0.1, respectively. The results of the simulations show that normal liver biologically weighted dose is restricted to 4.9 Gy-Eq (CBE; liver tumour: 2.5, normal liver: 0.94); the maximum, minimum, and mean tumour weighted dose are 43.1, 7.3, and 21.8 Gy-Eq, respectively, in 40 min irradiation. In this study, we show that (10)B entrapped WOW emulsion could be applied to novel intra-arterial boron delivery carrier for BNCT, and we show the possibility to apply BNCT to HCC. We can irradiate tumours as selectively and safety as possible, reducing the effects on neighbouring healthy tissues.

Analysis of the phospholipid hydroperoxide glutathione peroxidase mRNA in the rat spermatozoon and effect of selenium deficiency on the mRNA

Phospholipid hydroperoxide glutathione peroxidase (PHGPx) is a selenium (Se)-dependent glutathione peroxidase. It is reported that the relative PHGPx mRNA levels are much higher in the testis than in the other tissues. We have analyzed the existence and structure of the PHGPx mRNA in rat sperm and the changes in the level of the PHGPx mRNA after feeding with Se-deficient diets. We used 8-wk-old male Wistar strain rats given Se-adequate feed (control group, n=5) and Se-deficient diets with marginal levels of Se (0.03 ppm or less) (Sedeficient group, n=5) for 4 wk. The existence and level of the PHGPx mRNA in the cauda epididymal sperm, testis, and liver from the Seadequate rats were analyzed by the reverse transcription-polymerase chain reaction and the Southern blotting method. As a result, the existence of the PHGPx mRNA was demonstrated in the cauda epididymal sperm as well as in the testis and liver. Moreover, the subtype of the PHGPx mRNA in the rat sperm was the mitochondrial-type mRNA, which included a region corresponding to the mitochondrial transfer leader sequence. These results imply that the intracellular localization of PHGPx may be regulated by the transcription level. On the other hand, there was no significant difference between the control group and the Se-deficient group in the Se level of the cauda epididymal sperm and the level of the PHGPx mRNA. In conclusion, it has been demonstrated that the PHGPx mRNA exists in rat sperm for the first time. The analysis of the PHGPx mRNA in the sperm would be a useful tool for investigating the disfunction caused by the disorder of the level or structure of the PHGPx in the sperm.

Low level prenatal blood lead adversely affects early childhood mental development.

The effect of prenatal lead exposure on child development has been a topic of public health concern for decades. To estimate prenatal lead exposure effects on early childhood development, maternal blood (n = 364) and umbilical cord blood (n = 224) samples were collected during pregnancy and at delivery. Mental development was assessed using the Harold Ireton Early Child Development Inventory from 174 children. Maternal whole blood lead levels in the first trimester were significantly higher in children with developmental scores <20% than in those with normal scores (mean ± standard deviation: 6.3 ± 1.9 vs 4.0 ± 2.4 µg/dL, respectively, P = .01). Maternal blood lead levels in the first trimester were also inversely associated with the development scores (r = –0.155, P = .041). Logistic regression analysis showed a significant relationship between increasing maternal blood lead levels in the first trimester with low development scores (odds ratio = 1.74, 95% confidence interval = 1.18-2.57, P = .005). The findings of the present study showed a relatively low level of prenatal lead exposure (mean < 6.5 µg/dL) associated with lower developmental scores in early childhood.

Simultaneous determination of selenomethionine enantiomers in biological fluids by stable isotope dilution gas chromatography–mass spectrometry

A method for the stereoselective determination of D- and L-enantiomers of selenomethionine in mouse plasma was developed using gas chromatography-mass spectrometry with selected-ion monitoring (GC-MS-SIM). DL-[(2)H(3,)(82)Se]selenomethionine was used as analytical internal standard to account for losses associated with the extraction, derivatization and chromatography. Selenomethionine enantiomers in mouse plasma were purified by cation-exchange chromatography using BondElut SCX cartridge and derivatized with HCl in methanol to form methyl ester followed by subsequent N-acylation with optically active (+)-α-methoxy-α-trifluoromethylphenylacetyl chloride to form diastereomeric amide. Quantification was performed by SIM of the molecular-related ions of the diastereomers on the chemical ionization mode. The intra- and inter-day precision for D- and L-selenomethionine spiked to mouse plasma gave good reproducibility with relative standard deviation of 3% and 3% for D-selenomethionine and 6% and 3% for L-selenomethionine, respectively. The estimated amounts were in good agreement with the actual amounts spiked, the intra- and inter-day relative error being 5% and 2% for D-selenomethionine and 2% and 1% for L-selenomethionine, respectively. The present method is sensitive enough to determine pharmacokinetics of selenomethionine enantiomers.