Minimizing plasma temperature for antimatter mixing experiments

The ASACUSA collaboration produces a beam of antihydrogen atoms by mixing pure positron and antiproton plasmas in a strong magnetic field with a double cusp geometry. The positrons cool via cyclotron radiation inside the cryogenic trap. Low positron temperature is essential for increasing the fraction of antihydrogen atoms which reach the ground state prior to exiting the trap. Many experimental groups observe that such plasmas reach equilibrium at a temperature well above the temperature of the surrounding electrodes. This problem is typically attributed to electronic noise and plasma expansion, which heat the plasma. The present work reports anomalous heating far beyond what can be attributed to those two sources. The heating seems to be a result of the axially open trap geometry, which couples the plasma to the external (300 K) environment via microwave radiation.

A case study on severe damage at a tunnel in serpentinite rock mass

Abstract

Face squeezing, floor heave, and buckling of invert were found after a 10-day holiday in 2014 around the serpentinite face of a tunnel in Hokkaido, Japan. The damage continued for over 2 months, extending 400 m toward the entrance causing a massive roof fall. The tunnel was excavated again with a circular section and extra-thick shotcrete, and the face had crossed the damaged part 6 years after the damage occurred. Uniaxial and triaxial compression tests were carried out to obtain the mechanical properties of the serpentinite to clarify the severe damage mechanism at the tunnel. The main experimental findings are as follows. The uniaxial compressive strength of the serpentinite samples was very low, and the ratio of the strength to the estimated overburden pressure was extremely low. The parameter n indicated that the time-dependent deformation of the serpentinite was not large but the same as ordinary rocks. All specimens showed strain-hardening in the triaxial compression test, and the friction angle was very low by the brucite content. Only primary creep was observed in the multistage triaxial creep test. The pressure on the shotcrete from rock mass for the damaged tunnel was enough to cause creep deformation and failure of shotcrete. From the above findings, designing the concrete lining that can support the earth and water pressure is recommended for tunnel excavation in such a weak serpentinite rock mass, particularly with a very low friction angle by brucite.

Highlights

Endothelial-specific Ablation of Non-nuclear Estrogen Receptor alpha Signaling Deteriorates Vascular Remodelling Response

Background and introduction

The difference in cardiovascular disease risk between age-matched women and men narrows as transition through menopause in observational studies. Estrogen exerts complex physiological effects via its non-nuclear and nuclear actions. Experimental studies have shown that endothelial estrogen receptors mediate vasoprotection via endothelial nitric oxide production, reendothelialization, and atherosclerosis. Prior studies in vitro addressed estrogen's effects on endothelial cells and vascular smooth muscle cells, leading to vasoprotection. However, the in vivo evidences are lacking for beneficial effects of endothelium non-nuclear ERα signaling on vascular remodelling in response to injury.

Purpose

This study aims to clarify the impact of endothelial ERα non-nuclear signaling in the vasoprotection, using a novel mouse model lacking tissue-specific ERα non-nuclear signaling.

Methods

We identified the amino acids of ERα which were responsible for its binding to p85α subunit of phosphatidylinositol 3-kinase in vitro. We generated a novel mouse model in which non-nuclear signaling of ERα was ablated in endothelial cells by crossing Tie2-Cre transgenic mice with floxed ERα mutants (RR259/260AA) in which p85α and ERα interaction was disrupted.

Results

In endothelial cells isolated from ERαKI/KITie2 cre/+ animals, E2 failed to induce phosphorylation of Akt, confirming the absence of ERα non-nuclear signaling. Baseline characteristics at 8 to 12 weeks of age were undistinguishable between the genotypes, including body weight, systolic blood pressure, uterine weight and echocardiographic fractional shortening. We then assessed how vascular remodelling process was impacted in a carotid artery wire injury model. Histological analyses with Elastica van Gieson staining two weeks after injury revealed that estrogen dependent suppression of remodelling response (intima to medial ratio) was abolished in ERαki/kiTie2cre/+mice (P=0.0004). Masson's Trichrome staining showed that in the presence of E2 fibrosis was significantly higher in ERαki/kiTie2cre/+ mice than ERαki/kiTie2cre/− mice (P=0.0015).

Conclusions

We generated a novel mouse model for tissue-specific ablation of ERα non-nuclear signaling by interfering ERα-PI3K interaction. Our results demonstrate that the pivotal role for ERα non-nuclear signaling of endothelial cells in carotid arterial protection following injury with its minimal impact on baseline cardiovascular phenotype.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): Japan Heart Foundation Research Grant, SENSHIN Medical Research Foundation

Recent Developments from on Antihydrogen Detection

The ASACUSA Collaboration at CERNs Antiproton Decelerator aims to measure the ground state hyperfine splitting of antihydrogen with high precision to test the fundamental symmetry of CPT (combination of charge conjugation, parity transformation, and time reversal). For this purpose an antihydrogen detector has been developed. Its task is to count the arriving antihydrogen atoms and therefore distinguish backgroundevents (mainly cosmics) from antiproton annihilations originating from antihydrogen atoms which are produced only in small amounts. A central BGO crystal disk with position sensitive read-out detects the annihilation and a surrounding two-layered hodoscope is used for tracking charged secondaries. The hodoscope has been recently upgraded to allow precise vertex reconstruction. A machine learning analysis based on measured antiproton annihilations and cosmic rays has been developed to identify antihydrogen events.

Systemic administration of α-lipoic acid suppresses excitability of nociceptive wide-dynamic range neurons in rat spinal trigeminal nucleus caudalis

Although a modulatory role has been reported for α-lipoic acid (LA) on T-type Ca²⁺ channels in the nervous system, the acute effects of LA in vivo, particularly on nociceptive transmission in the trigeminal system, remain to be determined. The aim of the present study was to investigate whether acute intravenous LA administration to rats attenuates the excitability of wide dynamic range (WDR) spinal trigeminal nucleus caudalis (SpVc) neurons in response to nociceptive and non-nociceptive mechanical stimulation in vivo. Extracellular single unit recordings were made from seventeen SpVc neurons in response to orofacial mechanical stimulation of pentobarbital-anesthetized rats. Responses to both non-noxious and noxious mechanical stimuli were analyzed in the present study. The mean firing frequency of SpVc WDR neurons in response to both non-noxious and noxious mechanical stimuli was significantly and dose-dependently inhibited by LA (1-100 mM, i.v.) and maximum inhibition of the discharge frequency of both non-noxious and noxious mechanical stimuli was seen within 5 min. These inhibitory effects lasted for approximately 10 min. These results suggest that acute intravenous LA administration suppresses trigeminal sensory transmission, including nociception, via possibly blocking T-type Ca²⁺ channels. LA may be used as a therapeutic agent for the treatment of trigeminal nociceptive pain.

The ASACUSA antihydrogen and hydrogen program: results and prospects

The goal of the ASACUSA-CUSP collaboration at the Antiproton Decelerator of CERN is to measure the ground-state hyperfine splitting of antihydrogen using an atomic spectroscopy beamline. A milestone was achieved in 2012 through the detection of 80 antihydrogen atoms 2.7 m away from their production region. This was the first observation of 'cold' antihydrogen in a magnetic field free region. In parallel to the progress on the antihydrogen production, the spectroscopy beamline was tested with a source of hydrogen. This led to a measurement at a relative precision of 2.7×10^-9 which constitutes the most precise measurement of the hydrogen hyperfine splitting in a beam. Further measurements with an upgraded hydrogen apparatus are motivated by CPT and Lorentz violation tests in the framework of the Standard Model Extension. Unlike for hydrogen, the antihydrogen experiment is complicated by the difficulty of synthesizing enough cold antiatoms in the ground state. The first antihydrogen quantum states scan at the entrance of the spectroscopy apparatus was realized in 2016 and is presented here. The prospects for a ppm measurement are also discussed.This article is part of the Theo Murphy meeting issue 'Antiproton physics in the ELENA era'.

Circulatory CNP Rescues Craniofacial Hypoplasia in Achondroplasia

Achondroplasia is the most common genetic form of human dwarfism, characterized by midfacial hypoplasia resulting in occlusal abnormality and foramen magnum stenosis, leading to serious neurologic complications and hydrocephalus. Currently, surgery is the only way to manage jaw deformity, neurologic complications, and hydrocephalus in patients with achondroplasia. We previously showed that C-type natriuretic peptide (CNP) is a potent stimulator of endochondral bone growth of long bones and vertebrae and is also a potent stimulator in the craniofacial region, which is crucial for midfacial skeletogenesis. In this study, we analyzed craniofacial morphology in a mouse model of achondroplasia, in which fibroblast growth factor receptor 3 (FGFR3) is specifically activated in cartilage ( Fgfr3^ach mice), and investigated the mechanisms of jaw deformities caused by this mutation. Furthermore, we analyzed the effect of CNP on the maxillofacial area in these animals. Fgfr3^ach mice exhibited midfacial hypoplasia, especially in the sagittal direction, caused by impaired endochondral ossification in craniofacial cartilage and by premature closure of the spheno-occipital synchondrosis, an important growth center in craniomaxillofacial skeletogenesis. We crossed Fgfr3^ach mice with transgenic mice in which CNP is expressed in the liver under the control of the human serum amyloid-P component promoter, resulting in elevated levels of circulatory CNP ( Fgfr3^ach/SAP-Nppc-Tg mice). In the progeny, midfacial hypoplasia in the sagittal direction observed in Fgfr3^ach mice was improved significantly by restoring the thickness of synchondrosis and promoting proliferation of chondrocytes in the craniofacial cartilage. In addition, the foramen magnum stenosis observed in Fgfr3^ach mice was significantly ameliorated in Fgfr3^ach/SAP-Nppc-Tg mice due to enhanced endochondral bone growth of the anterior intraoccipital synchondrosis. These results clearly demonstrate the therapeutic potential of CNP for treatment of midfacial hypoplasia and foramen magnum stenosis in achondroplasia.

Mono-(2-ethylhexyl) Phthalate (MEHP) Induces Spermatogenic Cell Apoptosis in Guinea Pig Testes at Prepubertal Stage In Vitro

The effects of mono-(2-ethylhexyl) phthalate (MEHP), an active metabolite of di-(2-ethylhexyl) phthalate (DEHP), on prepubertal guinea pig testes in vitro were investigated. The testes of 35-day-old guinea pigs were surgically excised. They were seeded in a defined medium containing antibiotics and administered MEHP at concentrations of 1, 10, and 100 nmol/ml, respectively. The control groups were administered a similar volume of corn oil vehicle. The tissues were incubated for 3, 6, and 9 h. The specimens were collected at 3, 6, and 9 h after treatment. They were fixed in 4%paraformaldehyde or 5% glutaraldehyde. For quantitation of the apoptotic spermatogenic cells, the terminal dUTP nick end-labeling (TUNEL) staining was performed by light microscopy. Detachment and displacement of spermatogenic cells, thin seminiferous epithelia, and Sertoli cell vacuolization were observed. Maximal testicular damage was recognized at 100 nmol/ml 9 h after MEHP treatment. The percentage (%) of apoptotic spermatogenic cells significantly increased at 3, 6, and 9 h after treatment, compared to the control groups. Because the loss of spermatogenic cells by MEHP treatment varies among species, the present study, using guinea pigs, was designed and conducted to obtain further information.

The effects of acute cold exposure on morphology and gene expression in the heart of neonatal chicks

Cold exposure induces an increase in blood flow and blood pressure, and long-term exposure to cold causes cardiac hypertrophy. Neonatal chicks (Gallus gallus domesticus) are highly sensitive to cold exposure, because their capacity for thermogenesis is immature until 1 week after hatching. Hence, we hypothesized that the heart of chicks at around 1 week of age acutely responds to cold environment. To investigate the effect of acute (24 h) and long-term (2 weeks) cold on the heart of chicks, 7-day-old chicks were exposed to cold temperature (4 °C) or kept warm (30 °C). Chicks exposed to the cold showed cardiac hypertrophy with marked left ventricular (LV) chamber dilation and wall thickening. On the other hand, long-term cold exposure (2 weeks from 7-day-old) induced an increase in total ventricular mass, but not in LV morphological parameters. Then, we investigated the details of acute cardiac hypertrophy in chicks. Electron microscopy revealed that cardiomyocytes in the hypertrophied LV had enlarged mitochondria with less dense cristae. Although the mRNA expression of lipoprotein lipase in the LV of the cold-exposed chicks significantly increased, the mRNA expression of genes involved in fatty acid β-oxidation did not change in response to cold exposure. In addition, the mRNA expression of peroxisome proliferator-activated receptor gamma coactivator-1 alpha, which enhances mitochondrial biogenesis and function under physiological cardiac hypertrophy, increased in LV of cold-exposed chicks. The study found that acute cold exposure to neonatal chicks induces LV hypertrophy. However, these results suggest that acute cold exposure to chicks might induce both adaptive and maladaptive responses of the LV.

Frequent MED12 mutations in phyllodes tumours of the breast

BACKGROUND

Phyllodes tumours are rare fibroepithelial tumours of the breast, that include benign, borderline, and malignant lesions. Although the molecular basis of phyllodes tumours largely remains unknown, a recent exome study identified MED12 mutations as a sole recurrent genetic alteration in fibroadenoma, a common benign fibroepithelial tumour that shares some histological features with the phyllodes tumour.

METHODS

Forty-six phyllodes tumours and 58 fibroadenomas of the breast were analysed for MED12 mutations by using Sanger sequencing.

RESULTS

MED12 mutations were identified in 37 out of the 46 phyllodes tumours (80%). The prevalence of MED12 mutations was similar among benign (15/18, 83%), borderline (12/15, 80%), and malignant tumours (10/13, 77%). MED12 mutations were also identified in 36 of the 58 fibroadenomas (62%). The mutations were frequent among intracanalicular-type (24/32, 75%) and complex-type lesions (4/6, 67%), but were significantly less common among the pericanalicular-type lesions (8/20, 40%). A microdissection-based analysis showed that MED12 mutations were confined to the stromal components in both phyllodes tumours and fibroadenomas.

CONCLUSIONS

MED12 mutations were frequent among the phyllodes tumours of the breast, regardless of the tumour grade. Phyllodes tumours and fibroadenomas share, at least in part, a common genetic background.

The Concise Guide to PHARMACOLOGY 2013/14: overview

The Concise Guide to PHARMACOLOGY 2013/14 provides concise overviews of the key properties of over 2000 human drug targets with their pharmacology, plus links to an open access knowledgebase of drug targets and their ligands (www.guidetopharmacology.org), which provides more detailed views of target and ligand properties from the IUPHAR database. The full contents can be found at http://onlinelibrary.wiley.com/doi/10.1111/bph.12444/full. This compilation of the major pharmacological targets is divided into seven areas of focus: G protein-coupled receptors, ligand-gated ion channels, ion channels, catalytic receptors, nuclear hormone receptors, transporters and enzymes. These are presented with nomenclature guidance and summary information on the best available pharmacological tools, alongside key references and suggestions for further reading. A new landscape format has easy to use tables comparing related targets. It is a condensed version of material contemporary to late 2013, which is presented in greater detail and constantly updated on the website www.guidetopharmacology.org, superseding data presented in previous Guides to Receptors & Channels. It is produced in conjunction with NC-IUPHAR and provides the official IUPHAR classification and nomenclature for human drug targets, where appropriate. It consolidates information previously curated and displayed separately in IUPHAR-DB and GRAC and provides a permanent, citable, point-in-time record that will survive database updates.

Prognostic significance of amino-acid transporter expression (LAT1, ASCT2, and xCT) in surgically resected tongue cancer

BACKGROUND

Amino-acid transporters are necessary for the tumour cell growth and survival, and have a crucial role in the development and invasiveness of cancer cells. But, it remains unclear about the prognostic significance of L-type amino-acid transporter 1 (LAT1), system ASC amino-acid transporter-2 (ASCT2), and xCT expression in patients with tongue cancer. We conducted the clinicopathological study to investigate the protein expression of these amino-acid transporters in tongue cancer.

METHODS

Eighty-five patients with surgically resected tongue cancer were evaluated. Tumour sections were stained by immunohistochemistry for LAT1, ASCT2, xCT, 4F2hc/CD98hc (4F2hc), Ki-67, and microvessel density (MVD) determined by CD34, and p53.

RESULTS

L-type amino-acid transporter 1 and 4F2hc were highly expressed in 61% (52 out of 85) and 45% (38 out of 47), respectively. ASC amino-acid transporter-2 and xCT were positively expressed in 59% (50 out of 85) and 21% (18 out of 85), respectively. The expression of both LAT1 and ASCT2 was significantly associated with disease staging, lymph-node metastasis, lymphatic permeation, 4F2hc expression and cell proliferation (Ki-67). xCT expression indicated a significant association with advanced stage and tumour factor. By univariate analysis, disease staging, lymphatic permeation, vascular invasion, LAT1, ASCT2, 4F2hc, and Ki-67 had a significant relationship with overall survival. Multivariate analysis confirmed that LAT1 was an independent prognostic factor for predicting poor prognosis.

CONCLUSIONS

L-type amino-acid transporter 1 and ASCT2 can serve as a significant prognostic factor for predicting worse outcome after surgical treatment and may have an important role in the development and aggressiveness of tongue cancer.

Hyperfine structure constant of the neutron halo nucleus (11)Be(+)

The hyperfine splittings of ground state Be+11 have been measured precisely by laser-microwave double resonance spectroscopy for trapped and laser cooled beryllium ions. The ions were produced at relativistic energies and subsequently slowed down and trapped at mK temperatures. The magnetic hyperfine structure constant of Be+11 was determined to be A11=-2677.302 988(72)  MHz from the measurements of the mF-mF'=0-0 field independent transition. This measurement provides essential data for the study of the distribution of the halo neutron in the single neutron halo nucleus Be11 through the Bohr-Weisskopf effect.

ASC amino-acid transporter 2 (ASCT2) as a novel prognostic marker in non-small cell lung cancer

Background:

ASC amino-acid transporter 2 (ASCT2) is a major glutamine transporter that has an essential role in tumour growth and progression. Although ASCT2 is highly expressed in various cancer cells, the clinicopathological significance of its expression in non-small cell lung cancer (NSCLC) remains unclear.

Methods:

One hundred and four patients with surgically resected NSCLC were evaluated as one institutional cohort. Tumour sections were stained by immunohistochemistry (IHC) for ASCT2, Ki-67, phospho-mTOR (mammalian target of rapamycin), and CD34 to assess the microvessel density. Two hundred and four patients with NSCLC were also validated by IHC from an independent cohort.

Results:

ASC amino-acid transporter 2 was expressed in 66% of patients, and was closely correlated with disease stage, lymphatic permeation, vascular invasion, CD98, cell proliferation, angiogenesis, and mTOR phosphorylation, particularly in patients with adenocarcinoma (AC). Moreover, two independent cohorts confirmed that ASCT2 was an independent marker for poor outcome in AC patients.

Conclusions:

ASC amino-acid transporter 2 expression has a crucial role in the metastasis of pulmonary AC, and is a potential molecular marker for predicting poor prognosis after surgery.

Role of prolactin-like protein (PRL-L) in cold-induced increase of muscle mass in chicks

This study examined the hypothesis that a novel prolactin-like protein gene (PRL-L) is involved in cold-induced growth of skeletal muscle in chicks. Six-day-old chicks (Gallus gallus domesticus) were exposed to cold at 4°C or kept warm at 30°C for 24h. Cold exposure induced significant increases in PRL-L expression that coincided with increases in the weight of the sartorius muscle, which comprises both fast- and slow-twitch fibers. Meanwhile, no induction of PRL-L mRNA was observed in the heart, liver, kidney, brain, or fat. Myoblast cells that expressed PRL-L mRNA grew faster than untransduced cells in media containing 2% serum. These results suggested that PRL-L might be involved in in controlling cold-induced muscle growth of chicks.

Frequent GNAS mutations in low-grade appendiceal mucinous neoplasms

Background:

The molecular basis for the development of appendiceal mucinous tumours, which can be a cause of pseudomyxoma peritonei, remains largely unknown.

Methods:

Thirty-five appendiceal mucinous neoplasms were analysed for GNAS and KRAS mutations. A functional analysis of mutant GNAS was performed using a colorectal cancer cell line.

Results:

A mutational analysis identified activating GNAS mutations in 16 of 32 low-grade appendiceal mucinous neoplasms (LAMNs) but in none of three mucinous adenocarcinomas (MACs). KRAS mutations were found in 30 LAMNs and in all MACs. We additionally analysed a total of 186 extra-appendiceal mucinous tumours and found that GNAS mutations were highly prevalent in intraductal papillary mucinous tumours of the pancreas (88%) but were rare or absent in mucinous tumours of the colorectum, ovary, lung and breast (0–9%). The prevalence of KRAS mutations was quite variable among the tumours. The introduction of the mutant GNAS into a colorectal cancer cell line markedly induced MUC2 and MUC5AC expression, but did not promote cell growth either in vitro or in vivo.

Conclusion:

Activating GNAS mutations are a frequent and characteristic genetic abnormality of LAMN. Mutant GNAS might play a direct role in the prominent mucin production that is a hallmark of LAMN.

Immune cell infiltration as an indicator of the immune microenvironment of pancreatic cancer

Background:

The host immune reaction is represented by immune/inflammatory cell infiltrates. Here we systematically analysed tumour-infiltrating immune/inflammatory cells in pancreatic ductal carcinoma (PDC) and evaluated their clinicopathological impact.

Methods:

Using immunohistochemistry, we examined tumour-infiltrating CD68⁺ pan-macrophages, HLA-DR⁺CD68⁺ M1 macrophages (M1), CD163⁺ or CD204⁺ M2 macrophages (M2), CD66b⁺ neutrophils (Neu), CD4⁺ T cells (CD4⁺T), CD8⁺ T cells (CD8⁺T), and FOXP3⁺CD4⁺ regulatory T cells (Treg) in 212 cases of PDC, and conducted correlation and survival analyses using the Kaplan–Meier method and Cox proportional hazards model.

Results:

Higher levels of tumour-infiltrating pan-macrophages, M2, Neu, or the ratio of Tregs to CD4⁺T (%Treg) were significantly associated with shorter survival, whereas higher levels of tumour-infiltrating CD4⁺T, CD8⁺T, or the ratio of M1 to pan-macrophages (%M1) were significantly associated with longer survival. Survival analysis of pairs of these variables revealed that some of the resulting patient groups had exclusively longer survival. We then connected the apparently related factors, and two significant variables emerged: tumour-infiltrating CD4⁺T^high/CD8⁺T^high/%Treg^low and tumour-infiltrating %M1^high/M2^low. Multivariate survival analysis revealed that these variables were significantly correlated with longer survival and had a higher hazard ratio.

Conclusion:

Tumour-infiltrating CD4⁺T^high/CD8⁺T^high/%Treg^low and %M1^high/M2^low are independent prognosticators useful for evaluating the immune microenvironment of PDC.

Identification of ABCG2 dysfunction as a major factor contributing to gout

The ATP-binding cassette, subfamily G, member 2 gene ABCG2/BCRP locates in a gout-susceptibility locus (MIM 138900) on chromosome 4q. Recent genome-wide association studies also showed that the ABCG2 gene relates to serum uric acid levels and gout. Since ABCG2 is also known as a transporter of nucleotide analogs that are structurally similar to urate, and is an exporter that has common polymorphic reduced functionality variants, ABCG2 could be a urate secretion transporter and a gene causing gout. To find candidate mutations in ABCG2, we performed a mutation analysis of the ABCG2 gene in 90 Japanese patients with hyperuricemia and found six non-synonymous mutations. Among the variants, ATP-dependent urate transport was reduced or eliminated in five variants, and two out of the five variants (Q126X and Q141K) were frequently detected in patients. Haplotype frequency analysis revealed that there is no simultaneous presence of Q126X and Q141K in one haplotype. As Q126X and Q141K are a nonfunctional and half-functional haplotype, respectively, their genotype combinations are divided into four estimated functional groups. The association study with 161 male gout patients and 865 male controls showed that all of those who had dysfunctional ABCG2 had an increased risk of gout, and that a remarkable risk was observed in those with ≤1/4 function (OR, 25.8; 95% CI, 10.3-64.6; p = 3.39 × 10(-21)). In 2,150 Japanese individuals, the frequency of those with dysfunctional ABCG2 was more than 50%. Our function-based clinicogenetic analysis identified the combinations of dysfunctional variants of ABCG2 as a major contributing factor in Japanese patients with gout.

Pathogenic GLUT9 mutations causing renal hypouricemia type 2 (RHUC2)

Renal hypouricemia (MIM 220150) is an inherited disorder characterized by low serum uric acid levels and has severe complications such as exercise-induced acute renal failure and urolithiasis. We have previously reported that URAT1/SLC22A12 encodes a renal urate-anion exchanger and that its mutations cause renal hypouricemia type 1 (RHUC1). With the large health-examination database of the Japan Maritime Self-Defense Force, we found two missense mutations (R198C and R380W) of GLUT9/SLC2A9 in hypouricemia patients. R198C and R380W occur in highly conserved amino acid motifs in the "sugar transport proteins signatures" that are observed in GLUT family transporters. The corresponding mutations in GLUT1 (R153C and R333W) are known to cause GLUT1 deficiency syndrome because arginine residues in this motif are reportedly important as the determinants of the membrane topology of human GLUT1. Therefore, on the basis of membrane topology, the same may be true of GLUT9. GLUT9 mutants showed markedly reduced urate transport in oocyte expression studies, which would be the result of the loss of positive charges in those conserved amino acid motifs. Together with previous reports on GLUT9 localization, our findings suggest that these GLUT9 mutations cause renal hypouricemia type 2 (RHUC2) by their decreased urate reabsorption on both sides of the renal proximal tubule cells. However, a previously reported GLUT9 mutation, P412R, was unlikely to be pathogenic. These findings also enable us to propose a physiological model of the renal urate reabsorption via GLUT9 and URAT1 and can lead to a promising therapeutic target for gout and related cardiovascular diseases.

Increased expression of NOR-1 mRNA in the skeletal muscles of cold-exposed neonatal chicks

Nuclear receptor subfamily 4, group A (NR4A) subgroup orphan receptors are rapidly induced by various physiological stimuli and have been suggested to regulate oxidative metabolism and muscle mass in mammalian skeletal muscle. The results showed that the NR4A subgroup orphan receptor, NOR-1 (NR4A3), was acutely increased in skeletal muscles of neonatal chicks in response to short-term cold exposure. The increased NOR-1 gene expression was concomitant with cold-induced changes in gene expression of both myostatin and proliferator-activated receptor-gamma coactivator-1 (PGC-1α), and the increase in skeletal muscle mass. These observations suggest that NOR-1 might play a role in controlling skeletal muscle growth in cold-exposed neonatal chicks.

Electrically tuned spin-orbit interaction in an InAs self-assembled quantum dot

Electrical control over electron spin is a prerequisite for spintronics spin-based quantum information processing. In particular, control over the interaction between the orbital motion and the spin state of electrons would be valuable, because this interaction influences spin relaxation and dephasing. Electric fields have been used to tune the strength of the spin-orbit interaction in two-dimensional electron gases, but not, so far, in quantum dots. Here, we demonstrate that electrical gating can be used to vary the energy of the spin-orbit interaction in the range 50-150 µeV while maintaining the electron occupation of a single self-assembled InAs quantum dot. We determine the spin-orbit interaction energy by observing the splitting of Kondo effect features at high magnetic fields.

In vitro production of porcine embryos: current status, future perspectives and alternative applications

The pig is considered to be a suitable source of cells and organs for xenotransplants, as well as a transgenic animal to produce specific proteins, given the biological similarities it shares with human beings. However, the in vitro embryo production system in pigs is inefficient compared with those in other mammals, such as cattle or mice. Although numerous modifications have been applied to improve the efficiency of in vitro embryo production systems in pigs, not much progress has been made to overcome the problem of polyspermy, and low developmental ability due to insufficient cytoplasmic abilities of in vitro matured oocytes and improper culture conditions for the in vitro produced embryos. Recent achievements, such as the establishment of chemically defined medium and utilization of 'zona hardening' technique, have gained some success. However, further research for the reduction of polyspermy and detrimental effects of the culture systems in pigs is still needed.

[Apical tenting with polyglycolic acid sheet for primary pneumothorax]

We hypothesized that apical bullae recurred due to the dead space problem after apical bullectomy and caused recurrent pneumothorax. Apical tenting with a large polyglycolic acid (PGA) [15 x 15 cm] sheet was performed to attenuate over-expansion of the apical lung after bullectomy in the 43 patients (37 men and 6 women) with primary spontaneous pneumothorax. Shrinkage of the apical lung was estimated by measurement of the distance between the lower edge of the 1st rib and the apex on the chest radiography and computed tomography. Shrinkage was 9.22 (0-24) mm on the 10th postoperative day and 7.76 (2-17) mm at 3 months after surgery. Bullous formation recurred in 7 apical lungs of 6 patients. Minimal pneumothorax, which resolved with no treatment recurred in 3 patients. Thoracic drainage for recurrent pneumothorax was required in 1 patient. The degree of shrinkage at 3 months after bullectomy was not correlated to recurrent bullous formation, but correlated to recurrent pneumothorax. These data suggested that apical tenting method with a PGA sheet can reduce the recurrence rate of the pneumothorax after bullectomy, while it can not inhibit recurrent bullous formation.

Constant transmission of mitochondrial DNA in intergeneric cloned embryos reconstructed from swamp buffalo fibroblasts and bovine ooplasm

Although interspecies/intergeneric somatic cell nuclear transfer (iSCNT) has been proposed as a tool to produce offspring of endangered species, conflict between donor nucleus and recipient cytoplasm in iSCNT embryos has been identified as an impediment to implementation for agricultural production. To investigate the nuclear-mitochondrial interactions on the developmental potential of iSCNT embryos, we analyzed the mtDNA copy numbers in iSCNT embryos reconstructed with water buffalo (swamp type) fibroblasts and bovine enucleated oocytes (buffalo iSCNT). As controls, SCNT embryos were derived from bovine fibroblasts (bovine SCNT). Buffalo iSCNT and bovine SCNT embryos showed similar rates of cleavage and development to the 8-cell stage (P>0.05). However, buffalo iSCNT embryos did not develop beyond the 16-cell stage. Both bovine and buffalo mtDNA content in buffalo iSCNT embryos was stable throughout the nuclear transfer process, and arrested at the 8- to 16-cell stage (P>0.05). In bovine SCNT embryos that developed to the blastocyst stage, mtDNA copy number was increased (P<0.05). In conclusion, both the donor cell and recipient cytoplast mtDNAs of buffalo iSCNT embryos were identified and maintained through the iSCNT process until the 8-16-cell stage. In addition, the copy number of mtDNA per embryo was a useful monitor to investigate nuclear-mitochondrial interactions.

Extrapulmonary neuroendocrine tumors: An institutional experience of 337 patients at the National Cancer Center Hospital in Japan

293

Background: Extrapulmonary neuroendocrine tumors (EPNET) are a rare and heterogeneous disease entity, and little information regarding these tumors is available. The aim of the present study was to clarify the clinical behavior, treatment strategy, and outcome of EPNET arising from various primary sites.

Methods: We retrospectively reviewed the medical records of 337 patients with pathologically confirmed NET arising from extrapulmonary site between January 2000 and December 2008 at the National Cancer Center Hospital of Japan.

Results: The major primary tumor site was the rectum followed by the pancreas and stomach. Among the gastrointestinal tract tumors, 113 patients had NET from the foregut, 92 patients from the hindgut, and only 4 patients from the midgut. The median patient age was 60 years, and 57% of the patients were male. The histologic grade was as follows: 39% were well-differentiated neuroendocrine tumors (WDNET); 20% were well-differentiated neuroendcrine carcinomas (WDNEC); 33% were poorly differentiated neuroendocrine carcinomas (PDNEC); and 8% were mixed exocrine-endocrine tumors (Mixed). Most NETs from the rectum or duodenum are WDNET, whereas the ratio of PDNEC was high among NET from the genital organs or esophagus. The treatment strategy was associated with the clinical stage or the primary organ; in particular, 94% of the localized rectal NET were resected endoscopically. The 2-year survival rate for all the patients were 70%. A multivariate analysis demonstrated that distant disease of clinical stage and PDNEC of histological grade had a stronger impact on a poor outcome than the primary tumor site. The 2-year survival rate among the patients with WDNET, WDNEC and PDNEC were 97%, 80% and 36%, respectively, and 94%, 72%, and 32% of the patients had localized, regional, and distant disease, respectively.

Conclusions: Japanese patients with EPNET have different clinicopathological features such as the primary organ or treatment procedure compared with previous reports in Western countries. Identifying the precise clinical stage and histological grade of patients with NET is essential because these factors influence the patient outcome.

No significant financial relationships to disclose.

101 EXTERNAL PARAMETRIC INDICATORS OF IN VITRO DEVELOPMENTALLY COMPETENT WATER BUFFALO OOCYTES

External parametric indicators for in vitro developmentally competent water buffalo oocytes were determined. Oocytes were retrieved from ovarian follicles and classified based on the 1) density of surrounding cumulus cells (Rank A, n = 94: with >5 layers, Rank B, n = 73: with 3 to 5 layers, Rank C, n = 73: with <3 layers, Rank D, n = 63: with irregular or denuded from cumulus cells, and Rank E, n = 42: with expanded cumulus cells, and 2) granulation of ooplasm (Homogeneous, n = 164: evenly granulated, Heterogeneous, n = 180: not evenly granulated where some part is either light or dark), 3) size of the ooplasm, n = 647 (<100, n = 87; 100–119, n = 312; 120–139, n = 164; ≥140 μm, n = 84), and 4) size of the donor antral follicle, n = 688 (<2, n = 244; 2 to 3.9, n = 221; 4 to 5.9, n = 116; 6 to 7.9, n = 61; ≥8 mm, n = 46). Oocytes classified based on these parameters were matured for 22 to 24 h and the nuclear maturation was examined with cleavage rate and blastocyst development rate assessed after in vitro fertilization. To validate the hypothesis that oocytes with compact cumulus (n = 248) are at growing phase while those with loose cumulus (n = 270) are at developmental phase, they were matured and fertilized in vitro at shorter (20 to 22 h) or longer (24 to 26 h) period and embryo development was assessed. Each study was replicated 5 to 10 times. Data were statistically analysed by chi-square test, Fisher’s exact test, and correlation analysis. Results showed that oocytes surrounded by multi-layers (>5 layers) of cumulus cells had highest developmental competence. Oocytes with a diameter of <100 μm lacked developmental competence, evidenced by the failure to develop to metaphase II (MII) after in vitro maturation (IVM), whereas oocytes with diameter of ≥100 μm developed to MII and cleaved after IVF. Optimum cleavage (96.8%) and blastocyst development (27.0%) was observed in oocytes with ≥120 μm. The size of the donor follicle was linearly correlated with oocyte developmental competence with follicles ≥6 mm containing highly developmentally competent oocyte. Based on the findings, oocytes surrounded by >3 layers of compact or loose cumulus with evenly granulated and with ∼110 μm diameter ooplasm and derived from ≥4 mm follicles are developmentally competent. Oocytes with a compact cumulus required 24 to 26 h of IVM while those with loose cumulus required 20 to 22 h of IVM for optimum blastocyst development. These results suggest that the density and compactness of the surrounding cumulus, and the diameter of ooplasm and donor follicles are positive indicators for oocytes with developmental competence.

Synthesis of cold antihydrogen in a cusp trap

We report here the first successful synthesis of cold antihydrogen atoms employing a cusp trap, which consists of a superconducting anti-Helmholtz coil and a stack of multiple ring electrodes. This success opens a new path to make a stringent test of the CPT symmetry via high precision microwave spectroscopy of ground-state hyperfine transitions of antihydrogen atoms.

Identification of tamaraw (Bubalus mindorensis) from natural habitat-derived fecal samples by PCR-RFLP analysis of cytochrome b gene

Fecal DNA analysis is a useful tool for the investigation of endangered species. Tamaraw (Bubalus mindorensis) is endemic to the Philippine island of Mindoro but knowledge of its genetic and ecological information is limited. In this study, we developed a species identification method for tamaraw by fecal DNA analysis. Eighteen feces presumed to be from tamaraw were collected in Mount Iglit-Baco National Park and species-known feces from domestic buffaloes and cattle were obtained from a farm. Additionally, one species-unknown fecal sample was obtained in Mount Aruyan Preserve, where the sighting of tamaraw has not been reported in recent years. Based on DNA sequence data previously reported, the genus Bubalus- and tamaraw-specific primers for PCR of cytochrome b gene were newly designed. The Bubalus-specific primer yielded a 976 bp fragment of cytochrome b for all fecal samples from tamaraw and domestic buffaloes, but not for cattle, whereas the tamaraw-specific primer yielded a 582 bp fragment for all tamaraw fecal samples and for one of the four domestic buffalo samples. PCR-RFLP (restriction fragment length polymorphism) analysis of the 976 bp PCR fragment with AvrII or BsaXI provided distinct differences between tamaraw and domestic buffalo. PCR-RFLP analysis also showed that the species-unknown sample obtained in Mount Aruyan Preserve, originates from tamaraw.

Target structure induced suppression of the ionization cross section for very low energy antiproton-hydrogen collisions

Low energy antiprotons have been used previously to give benchmark data for theories of atomic collisions. Here we present measurements of the cross section for single, nondissociative ionization of molecular hydrogen for impact of antiprotons with kinetic energies in the range 2-11 keV, i.e., in the velocity interval of 0.3-0.65 a.u. We find a cross section which is proportional to the projectile velocity, which is quite unlike the behavior of corresponding atomic cross sections, and which has never previously been observed experimentally.

ARAP3 inhibits peritoneal dissemination of scirrhous gastric carcinoma cells by regulating cell adhesion and invasion

During the analysis of phosphotyrosine-containing proteins in scirrhous gastric carcinoma cell lines, we observed an unusual expression of Arf-GAP with Rho-GAP domain, ankyrin repeat and PH domain 3 (ARAP3), a multimodular signaling protein that is a substrate of Src family kinases. Unlike other phosphotyrosine proteins, such as CUB domain-containing protein 1 (CDCP1) and Homo sapiens chromosome 9 open reading frame 10/oxidative stress-associated Src activator (C9orf10/Ossa), which are overexpressed and hyperphosphorylated in scirrhous gastric carcinoma cell lines, ARAP3 was underexpressed in cancerous human gastric tissues. In this study, we found that overexpression of ARAP3 in the scirrhous gastric carcinoma cell lines significantly reduced peritoneal dissemination. In vitro studies also showed that ARAP3 regulated cell attachment to the extracellular matrix, as well as invasive activities. These effects were suppressed by mutations in the Rho-GTPase-activating protein (GAP) domain or in the C-terminal two tyrosine residues that are phosphorylated by Src. Thus, the expression and phosphorylation state of ARAP3 may affect the invasiveness of cancer by modulating cell adhesion and motility. Our results suggest that ARAP3 is a unique Src substrate that suppresses peritoneal dissemination of scirrhous gastric carcinoma cells.

Evaluation of developmental competence of in vitro-produced porcine embryos based on the timing, pattern and evenness of the first cleavage and onset of the second cleavage

The following selection markers for in vitro-produced porcine embryos were investigated: the timing, pattern and evenness of the first cleavage and the timing of the second cleavage. The embryos that cleaved by 30 h post-insemination (hpi) developed to blastocysts at a significantly higher rate (60.9%) and with a significantly higher cell number (33.6 cells) than those of embryos cleaved by 36 hpi (26.4% and 23.6 cells, respectively, P<0.05). Blastocyst proportions derived from 2- and 3-cell embryos cleaved by 30 hpi (68.2 and 65.3%, respectively) were significantly higher than those of 4- and >4-cell embryos (46.3 and 42.6%, respectively, P<0.05). The cell number per blastocyst generated from 2-cell embryos was significantly greater (37.3 cells) than those from 3-, 4- and >4-cell embryos (23.6-27.8 cells, P<0.05). Among embryos cleaved by 30 hpi, the blastocysts derived from evenly cleaved embryos (40.6 cells) were of significantly better quality than those derived from unevenly cleaved embryos (33.2 cells, P<0.05), although their blastocyst rates did not differ. The evenly cleaved embryos that underwent subsequent cleavage within 18 h had significantly higher blastocyst rates (72.7-81.0%) and quality (36.2-40.9 cells) than those without subsequent cleavage (48.3% and 22.5 cells, respectively, P<0.05) during the same period. In conclusion, the timing, pattern and evenness of the first cleavage and the timing of the second cleavage affected the developmental competence and quality of in vitro-produced porcine embryos.

126 DEVELOPMENT OF SINGLE BLASTOMERES DERIVED FROM PORCINE TWO-CELL EMBRYOS

Monozygotic mice and calves have been produced from demi-2-cell embryos (Wang K et al. 1997 J. Reprod. Dev. 43, 91-95; Tagawa M et al. 2008 Theriogenology 69, 574-82). These studies proved that single blastomeres of 2-cell embryos could still develop properly after being separated. However, such studies are very difficult to perform in pigs due to multiple pregnancies and relatively low success of embryo transfer. The production of genetically identical animals is very useful for animal husbandry, particularly to increase the number of progeny derived from genetically valuable parents. In the present study, we compared the developmental ability to the blastocysts and their quality in terms of total cell number and gene expression of blastomere pairs derived from 2-cell embryos (pair of blastomere for short). Evenly cleaved 2-cell embryos were collected during 24 to 30 h after IVF and IVM of follicular oocytes. They were split into pairs of single blastomeres by gentle pipetting after Pronase treatment for removal of zona pellucida. Blastomeres were then cultured separately in polydimethylsiloxane (PDMS) micro-wells. Embryos were cultured in IVC-PyrLac from Days 0 to 2 (Day 0 was defined as the day of IVF) and in IVC-Glu for next 4 days (Kikuchi K et al. 2002 Biol. Reprod. 66, 1033-1041). At Day 6, single blastocysts were collected for total cell number or gene expression analysis. Eight replications were performed for each analysis. Three genes chosen for real-time PCR were high-mobility group box 1 (HMGB1); ATP synthase, H1 transporting, mitochondrial F1 (ATP5A1); and the small nuclear ribonuclear proteins (LSM2). These genes are considered as markers to identify embryos with high development competence (Withworth KM et al. 2005 Biol. Reprod. 72, 1437-1451). The expression levels were normalized to the housekeeping gene Tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein (YWHAG) using standard curve method. Assessment of 42 blastomere pairs at Day 6 showed that the percentages of the pairs developed to blastocysts (36.6 ± 5.3%) or degenerated (46.3 ± 10.3%) were significantly higher than those of the pairs in which one developed to blastocyst and the other degenerated (17.1 ± 7.8%, P < 0.05, 1-way ANOVA followed by Tukey test). Assessment of two blastocysts derived from one pair of blastomeres showed that one blastocyst (B#1) had better morphology than the other (B#2) in term of expansion and B#1s had significantly higher cell number (31.6 ± 2.9) than that of B#2s (19.1 ± 1.9; P < 0.05; 1-way ANOVA). Although the expression levels of ATP5A1, HMBG1, and LSM2 in B#1s (1.08 ± 0.37, 3.51 ± 1.01, and 2.63 ± 1.17, respectively) did not differ from those in B#2s (0.39 ± 0.13, 1.18 ± 0.38, and 1.68 ± 0.83, respectively), they tended to be higher in B#1s compared to B#2s (P < 0.1). In conclusion, blastomere pairs from the same origin had the same potential to develop to the blastocyst stage. However, the qualities of blastocysts in pairs were different.

Increased mass of slow-type skeletal muscles and depressed myostatin gene expression in cold-tolerant chicks

Temperature is maintained in birds by skeletal muscle shivering as well as by non-shivering thermogenesis in a cold environment because they lack brown adipose tissue, which is a mammalian thermogenic organ. Chicks acquire cold tolerance after their skeletal muscles mature. Here, we found that muscle fibers transformed to the slow-twitch type with increasing gene expression of peroxisome proliferator-activated receptor-gamma coactivator-1alpha (PGC-1alpha), and that the mass increased with decreasing myostatin gene expression, in the leg muscles of 7-day-old and younger chicks within 24 h of cold exposure. Muscle fibers did not transform and the mass did not increase within 24 h of cold exposure in muscles from chicks older than 8 days of age. Myostatin mRNA expression remained depressed in cold-tolerant muscles for 24 h, whereas cold-enhanced growth of the muscle continued for 48 h. Myostatin expression was depressed and muscle mass was increased only in chick leg muscles that comprised both fast- and slow-twitch fibers. These results suggest that the acute regulation of PGC-1alpha and myostatin gene expression in leg muscles is required for chicks to acquire cold tolerance up to 7 days of age.

Possible roles of myostatin and PGC-1alpha in the increase of skeletal muscle and transformation of fiber type in cold-exposed chicks: expression of myostatin and PGC-1alpha in chicks exposed to cold

This study examined the hypothesis that myostatin and PGC-1alpha are involved in the increase in skeletal muscle mass and transformation of fiber type in cold-exposed chicks. One-week-old chicks were exposed to acute (24h) or long-term (8d) cold at 4 degrees C or kept warm at 30 degrees C. Acute cold exposure induced a significant increase in the skeletal muscle weight and the ratio of slow- to fast-fiber specific troponin I expression (sTnI/fTnI), accompanied by a significant decrease in lactate dehydrogenase activity. Expression of myostatin mRNA in the muscle was significantly lower in cold-exposed chicks than in the controls, whereas PGC-1alpha mRNA expression was significantly enhanced. These changes in the gene expression rapidly returned to the levels of the control chicks after the end of cold exposure, whereas the changes in fiber type and enzymatic activity were not resumed within 24h after removal of cold exposure. On the other hand, long-term exposure to cold resulted in a remarkable increase in skeletal muscle weight, accompanied by a significant increase in the ratio of sTnI/fTnI and the enzymatic activities of cytochrome oxidase and lactate dehydrogenase. However, the expression level of myostatin mRNA in cold-exposed chicks was not different from that in their age-matched control chicks and that of PGC-1alpha mRNA was significantly lower than in the controls. These results indicate that myostatin and PGC-1alpha expression in the skeletal muscle rapidly change in response to acute cold, suggesting the possibility that these two genes could be involved in the increase in muscle mass and transformation of fiber type, respectively, at the initial stage of adaptation in cold-exposed chicks.

[Video-assisted thoracoscopic removal for mediastinal mature teratoma following extraction of cystic components]

Video-assisted thoracoscopic resection for mediastinal mature teratoma is sometimes converted to open thoracotomy. Because it has rich components including pancreatic tissue and dense adhesion, even when it is asymptomatic. Prior to thoracoscopic resection, extraction of the cystic components with the aid of a 20 Fr tube can provide a wide thoracoscopic view leading to easier complete removal. Between October 1998 and June 2008, 6 patients (1 man and 5 women) with benign mediastinal mature teratoma underwent the thoracoscopic operations. The average age was 36.3 (range, 24-54). The mean diameter was 9.0 cm (range, 5-11 cm). The mean operation time was 143 minutes and the mean blood loss was 103 ml. Neither complications nor tumor recurrences developed during the mean follow-up period of 3.4 years. The presented thoracoscopic surgery for benign mature teratoma is a feasible procedure.

[Port-access lobectomy for lung cancer: experience in the single institute]

We reviewed the data on 171 patients who underwent thoracoscopic lobectomy for lung cancer via 5 access ports at our institution between April 2005 and May 2008. Port-access lobectomy was completed in 153 patients and conversions to open thoracotomy were required in 18 patients. Among the above 153 patients, mean operative time was 145 minutes and the mean blood loss was 159 ml. Morbidity rate was 12% and mortality rate was 0.7%. Pathologic study demonstrated stage I in 106 patients (69%), stage II in 16 patients (11%), and stage III in 31 patients (20%). At mean follow-up of 635 days after surgery, the overall 3-year survival rates of the patients with non-small cell lung cancer at stage I, stage II, and stage III were 88%, 80%, and 79%, respectively. Port-access lobectomy with mediastinal lymph nodes dissection for lung cancer is feasible with low morbidity and mortality rates. Long-term outcomes should be reviewed in the near feature.

Migratory ability of chick primordial germ cells transferred into quail embryos

The migratory ability of chick primordial germ cells (PGCs) transferred into quail embryos was investigated. One, ten, twenty, fifty or one hundred chick PGCs were transferred into the dorsal aorta of 2.5-day-old quail embryos. One day later, the embryos were isolated, and serial sections were prepared after embedding in paraffin. The sections were then double-stained with periodic acid-Schiff (PAS) and hematoxylin, and the numbers of PAS-positive chick PGCs in the germinal epithelium, gonadal area, head area and trunk area of the embryos were determined. Approximately 70% of the PGCs were detected in the embryos 1 day after transfer, with roughly 60% in the gonadal region and 10% in the extragonadal region. This ratio was consistent regardless of the number of PGCs transferred into the embryos. These data suggest that migration of chick PGCs into the gonadal and extragonadal regions of the quail embryo occurs probabilistically regardless of the number of chick PGCs transferred into quail embryos.

Regulation of placental amino acid transporter activity by mammalian target of rapamycin

The activity of placental amino acid transporters is decreased in intrauterine growth restriction (IUGR), but the underlying regulatory mechanisms have not been established. Inhibition of the mammalian target of rapamycin (mTOR) signaling pathway has been shown to decrease the activity of the system L amino acid transporter in human placental villous fragments, and placental mTOR activity is decreased in IUGR. In the present study, we used cultured primary trophoblast cells to study mTOR regulation of placental amino acid transporters in more detail and to test the hypothesis that mTOR alters amino acid transport activity by changes in transporter expression. Inhibition of mTOR by rapamycin significantly reduced the activity of system A (−17%), system L (−28%), and taurine (−40%) amino acid transporters. mRNA expression of isoforms of the three amino acid transporter systems in response to mTOR inhibition was measured using quantitative real-time PCR. mRNA expression of l-type amino acid transporter 1 (LAT1; a system L isoform) and taurine transporter was reduced by 13% and 50%, respectively; however, mTOR inhibition did not alter the mRNA expression of system A isoforms (sodium-coupled neutral amino acid transporter-1, -2, and -4), LAT2, or 4F2hc. Rapamycin treatment did not significantly affect the protein expression of any of the transporter isoforms. We conclude that mTOR signaling regulates the activity of key placental amino acid transporters and that this effect is not due to a decrease in total protein expression. These data suggest that mTOR regulates placental amino acid transporters by posttranslational modifications or by affecting transporter translocation to the plasma membrane.