Revisiting the magnetic structure of Holmium at high pressure by using neutron diffraction.

Low-temperature neutron diffraction experiments at [Formula: see text] GPa have been conducted to investigate the magnetic structures of metallic Holmium at high pressures by employing a long d-spacing high-flux diffractometer and a Paris-Edinburgh press cell inside a cryostat. We find that at [Formula: see text] GPa and [Formula: see text] K, no nuclear symmetry change is observed, keeping therefore the hexagonal closed packed (hcp) symmetry at high pressure. Our neutron diffraction data confirm that the ferromagnetic state does not exist. The magnetic structure corresponding to the helimagnetic order, which survives down to 5 K, is fully described by the magnetic superspace group formalism. These results are consistent with those previously published using magnetization experiments.

Coexistence of Superconductivity and Charge Density Waves in Tantalum Disulfide: Experiment and Theory.

The coexistence of charge density wave (CDW) and superconductivity in tantalum disulfide (2H-TaS_{2}) at low temperature is boosted by applying hydrostatic pressures to study both vibrational and magnetic transport properties. Around P_{c}, we observe a superconducting dome with a maximum superconducting transition temperature T_{c}=9.1 K. First-principles calculations of the electronic structure predict that, under ambient conditions, the undistorted structure is characterized by a phonon instability at finite momentum close to the experimental CDW wave vector. Upon compression, this instability is found to disappear, indicating the suppression of CDW order. The calculations reveal an electronic topological transition (ETT), which occurs before the suppression of the phonon instability, suggesting that the ETT alone is not directly causing the structural change in the system. The temperature dependence of the first vortex penetration field has been experimentally obtained by two independent methods. While a d wave and single-gap BCS prediction cannot describe the lower critical field H_{c1} data, the temperature dependence of the H_{c1} can be well described by a single-gap anisotropic s-wave order parameter.

Responses of the weed Bidens pilosa L. to exogenous application of the steroidal saponin protodioscin and plant growth regulators 24-epibrassinolide, indol-3-acetic acid and abscisic acid.

The exogenous application of plant hormones and their analogues has been exploited to improve crop performance in the field. Protodioscin is a saponin whose steroidal moiety has some similarities to plant steroidal hormones, brassinosteroids. To test the possibility that protodioscin acts as an agonist or antagonist of brassinosteroids or other plant growth regulators, we compared responses of the weed species Bidens pilosa L. to treatment with protodioscin, brassinosteroids, auxins (IAA) and abscisic acid (ABA). Seeds were germinated and grown in agar containing protodioscin, dioscin, brassinolides, IAA and ABA. Root apex respiratory activity was measured with an oxygen electrode. Malondialdehyde (MDA) and antioxidant enzymes activities were assessed. Protodioscin at 48-240 µm inhibited growth of B. pilosa seedlings. The steroidal hormone 24-epibrassinolide (0.1-5 µm) also inhibited growth of primary roots, but brassicasterol was inactive. IAA at higher concentrations (0.5-10.0 µm) strongly inhibited primary root length and fresh weight of stems. ABA inhibited all parameters of seedling growth and also seed germination. Respiratory activity of primary roots (KCN-sensitive and KCN-insensitive) was activated by protodioscin. IAA and ABA reduced KCN-insensitive respiration. The content of MDA in primary roots increased only after protodioscin treatment. All assayed compounds increased APx and POD activity, with 24-epibrassinolide being most active. The activity of CAT was stimulated by protodioscin and 24-epibrassinolide. The results revealed that protodioscin was toxic to B. pilosa through a mechanism not related to plant growth regulator signalling. Protodioscin caused a disturbance in mitochondrial respiratory activity, which could be related to overproduction of ROS and consequent cell membrane damage.

Contactless electrical conductivity measurement of metallic submicron-grain material: Application to the study of aluminum with severe plastic deformation.

We measured the electrical conductivity σ of aluminum specimen consisting of submicron-grains by observing the AC magnetic susceptibility resulting from the eddy current. By using a commercial platform for magnetic measurement, contactless measurement of the relative electrical conductivity σn of a nonmagnetic metal is possible over a wide temperature (T) range. By referring to σ at room temperature, obtained by the four-terminal method, σn(T) was transformed into σ(T). This approach is useful for cylinder specimens, in which the estimation of the radius and/or volume is difficult. An experiment in which aluminum underwent accumulative roll bonding, which is a severe plastic deformation process, validated this method of evaluating σ as a function of the fraction of high-angle grain boundaries.

Specific heat study of an S = 1/2 alternating Heisenberg chain system: F5PNN in a magnetic field.

We have measured the specific heat of an S = 1/2 antiferromagnetic alternating Heisenberg chain pentafulorophenyl nitronyl nitroxide in magnetic fields up to H > H(C2). This compound has a field-induced magnetic ordered (FIMO) phase between H(C1) and H(C2). Characteristic behaviors are observed depending on the magnetic field up to above H(C2) outside of the H-T boundary for the FIMO. The temperature and field dependence of the specific heat are qualitatively in good agreement with the theoretical calculation on an S = 1/2 two-leg ladder [Wang et al., Phys. Rev. Lett. 84, 5399 (2000)]]. This agreement suggests that the observed behaviors are related with the low-energy excitation in the Tomonaga-Luttinger liquid.

UFT and mitomycin plus tamoxifen for stage II, ER-positive breast cancer. Hokkaido ACETBC Study Group.

A trial was designed to examine the combination of UFT and mitomycin (Mutamycin) plus tamoxifen (Nolvadex) as postoperative adjuvant therapy in the treatment of patients with stage II, estrogen receptor (ER)-positive primary breast cancer. Mitomycin was administered intravenously at 13 mg/m2 on the day of surgery. Patients judged to be ER-positive were randomly allocated to either group A, which received oral tamoxifen 20 mg/day 14 days after surgery for 2 years, or group B, receiving oral UFT 400 mg/day plus tamoxifen 20 mg/day. A total of 219 patients were enrolled in group A, of which 213 (97.3%) were determined to be eligible; 225 patients enrolled in group B and 223 (99.1%) were eligible. The 5-year survival rates were 93.0% for group A and 95.4% for group B, with no significant difference between groups. The 5-year relapse-free survival rates were 83.1% for group A and 90.7% for group B, a significant advantage (P = .020) for the UFT plus tamoxifen group. Combination therapy with mitomycin, tamoxifen, and UFT proved to be an effective postoperative chemoendocrine therapy for stage II, ER-positive breast cancer.

Prolonged function of hepatocytes transplanted into the spleens of Nagase analbuminemic rats.

Hepatocytes isolated from F344 rats were transplanted into the spleens of congenic Nagase analbuminemic rats (NARs). The morphology and function of the transplanted hepatocytes were investigated after 18 months. The hepatocytes had formed nodules that occupied approximately 35% of the area of the splenic parenchyma on microscopic examination. Ultrastructural examination demonstrated that the organelles of the transplanted cells were indistinguishable from those of normal hepatocytes. The serum albumin level in NARs at 18 months after intrasplenic transplantation (HCTx) was about 3.6% of that in normal rats. We confirmed that the hepatocytes in the spleen produced albumin and increased the serum albumin level in NARs with HCTx. The NAR model demonstrates the effect of HCTx and prolonged changes in the morphology of the hepatized spleen.

Allogeneic hepatocyte transplantation: contribution of Fas-Fas ligand interaction to allogeneic hepatocyte rejection.

Hepatocyte transplantation is a potential therapeutic modality for overcoming the shortage of liver donors, and the clinical application of allogeneic hepatocyte transplantation has been considered. However, there are two major problems with allogeneic hepatocyte transplantation: protection of transplanted hepatocytes from rejection and stimulation of the rapid proliferation of surviving cells. Without immunosuppression, allogeneic hepatocytes are rapidly rejected within a few days after transplantation, even though it is relatively easy to induce immunotolerance after allogeneic whole liver transplantation. Accordingly, different rejection mechanisms seem to operate after allogeneic hepatocyte transplantation and whole liver transplantation. To overcome the rejection of transplanted hepatocytes, induction of donor-specific unresponsiveness to graft without compromising the host immune system would be ideal. We previously reported that the Fas-Fas ligand system plays a critical role in the CD28-independent pathway of hepatocyte rejection. Therefore, blockade of rejection using CTLA4 immunoglobulin (CTLA4Ig) or anti-CD80/86 monoclonal antibodies and anti-FasL monoclonal antibody may prolong the survival of transplanted allogeneic hepatocytes. Furthermore, administration of hepatocyte growth factor (HGF) can promote the proliferation of allogeneic hepatocytes and this may lead to the development of a functioning liver substitute.

Fatty acid omega and (omega-1)-oxidation within intrasplenically transplanted fetal hepatocytes.

BACKGROUND: The expression and enzymatic activity of the cytochrome P450 LAomega within intrasplenically transplanted hepatocytes was investigated. METHODS: Fetal hepatocytes were harvested from spontaneously hypertensive rats and transplanted into recipient adult spontaneously hypertensive rat spleens. RESULTS: Microscopic examination revealed masses of hepatocytes in the red pulp. Immunochemical studies detected cytochrome P450 LAomega in transplanted hepatocytes by 6 and 10 weeks after transplantation. Cytochrome P450 LAomega mRNA accumulates at 6 weeks after transplantation. Cytochrome P450-arachidonic acid omega/omega-1 hydroxylase activity (formation of 20/19-hydroxyeicosatetraenoic acid) was detected at 10 weeks after transplantation. CONCLUSION: These results demonstrated that fetal hepatocytes grow in the spleen and function similarly to adult hepatocytes.

Multiporous cellulose microcarrier for the development of a hybrid artificial liver using isolated hepatocytes.

BACKGROUND: This study was aimed at developing an optimal method for immobilizing isolated hepatocytes in cellulose multiporous microcarriers (MCs) and evaluating the metabolic activity of MC-immobilized hepatocytes. MATERIALS AND METHODS: Hepatocytes isolated from the livers of male Wistar rats were immobilized in collagen-coated MCs by intermittent stirring (30 rpm for 2 min per 15 min) for 180 min or accumulation methods. The accumulation method was performed by pouring aliquots of hepatocyte suspension (8 x 10(5)) and MC suspension (1 mg) in turn onto a nylon mesh (pore size: 100 micron). The metabolic activity of MC-immobilized hepatocytes in floating culture and in a newly developed bioreactor was evaluated. The metabolic activity of MC-immobilized hepatocytes in the bioreactor was also evaluated in in vitro perfusion of a hollow-fiber-based hybrid artificial liver support system. RESULTS: The accumulation method immobilized 20 times more hepatocytes in collagen-coated MCs than the intermittent stirring method (P < 0.01). Morphological observation of hepatocyte-immobilized MCs revealed that many hepatocytes were immobilized deep within the MCs maintaining a spherical shape and normal microvilli on their surface. MC-immobilized hepatocytes in floating culture revealed similar NH3 metabolism and glucose synthesis to monolayer-cultured hepatocytes, and this metabolic activity was maintained during 9h of floating culture. MC-immobilized hepatocytes in a bioreactor also showed similar NH3 metabolism to monolayer-cultured hepatocytes. The NH3 metabolism of MC-immobilized hepatocytes in in vitro perfusion of a hybrid artificial liver support system was 241.5 microg/h/mg protein/m2 membrane surface. CONCLUSIONS: The results of this study indicate that the accumulation method was optimal for immobilizing isolated rat hepatocytes in MCs and that MC-immobilized hepatocytes maintained their metabolic activity for a long period.

[Organ transplant network in Japan: current status and its role].

The Role of Organ Transplant Network are the encouragement of the organ transplantation and fair organ sharing. Its principled are united, neutral open and nonprofit organization, so as to secure the fair and quick organ sharing based on the uniform allocation policy. Japan Kidney Transplant Network was established in 1995 nad reorganized into multi-organ sharing network, Japan Organ Transplant Network in 1997, when Japan Organ transplant Act was enacted. It consists of transplant coordinators, physicians, transplant surgeons, kidney banks, local administration, academic standings, other organization/associations and others. There are several committee, in which special subjects on organ transplantation and related matters are consulted, and review system in which each case is assessed and judged. And principal and essential items are decided by the board of members and then by the general assembly. The new computer system was introduced and registrants data are renewed every year, and recipient selection is done based on the latest registrants data. Standardized HLA examination tray was introduced and class II antigen was examined by means of DNA typing since 1997, which enabled more precise and accurate search. Hereafter, the education and encouragement of transplant coordinators to raise themselves and the more effective and extended distribution of donor cards are indispensable to promote organ donation/transplantation.

Critical role of Fas/Fas ligand interaction in CD28-independent pathway of allogeneic murine hepatocyte rejection.

Cytolytic induction of T cells requires both the T-cell receptor (TCR)-mediated antigenic stimulation and the CD28-mediated co-stimulatory signal. Blockade of the interactions between CD28 and its ligands, CD80 and CD86, prolongs the survival of allografts in some transplantation models. However, we found that allogeneic hepatocytes were completely rejected within 7 days after intrasplenic transplantation, even when treated with monoclonal antibodies (mAbs) against CD80 and CD86 (anti-CD80/86). Recent studies have shown that there are two main mechanisms of T-cell-mediated cytotoxicity, perforin-based and Fas-based ones. It has been shown that the liver is highly sensitive to induction of apoptosis by an agonistic anti-Fas mAb. We then investigated the role of the Fas/Fas ligand (FasL) system in the CD28-independent allogeneic hepatocyte rejection. With the anti-CD80/86 mAb treatment, hepatocytes from C57BL/6 lpr/lpr (B6 lpr) mice, which express little Fas antigen, could survive for 7 days after intrasplenic transplantation, and hepatocytes from C57BL/6 (B6) mice could also survive for 7 days in the spleen of C3H/ He gld/gld (C3H gld) mice, which express no functional FasL. CD28-independent induction of cytotoxicity against allogeneic hepatocytes was not observed when the effector cells were derived from C3H gld mice. These results indicated that the Fas/FasL system plays a critical role in the CD28-independent pathway of allogeneic hepatocyte rejection.

Enzymatic activity and expression of cytochrome P450 LA omega within intrasplenically transplanted fetal hepatocytes in spontaneously hypertensive rats.

We examined the expression and enzymatic activity of cytochrome P450 LA omega within transplanted hepatocytes. Fetal hepatocytes were harvested at day 20 of gestation from spontaneously hypertensive rats (SHRs) and transplanted into recipient adult SHR spleens. Microscopic examination of the recipient spleens at 4 and 10 wk after transplantation revealed masses of hepatocytes with cord-like structures in the red pulp. Immunochemical studies detected cytochrome (cyto) P450 LA omega in the fetal hepatocytes before transplantation without prior induction. Although the cyto P450 LA omega was not detected by the second week after transplantation, by the 6th and 10th wk after transplantation, it was. Cyto P450-arachidonic acid omega/omega-1 hydroxylase activity (formation of 20- and 19-hydroxyeicosatetraenoic acid) was detected at 10 wk after transplantation, but not 2 or 6 wk after transplantation. These results demonstrated that fetal hepatocytes can be transplanted successfully into recipient spleens and then grow in the spleens, as in the case of the adult hepatocyte response.

Functional assessment of proliferating hepatocytes stimulated by hepatic stimulatory substance in ascorbic acid biosynthetic enzyme-deficient rats.

The functional ability of hepatic stimulatory substance (HSS)-stimulated proliferating hepatocytes was investigated by intrasplenic and/or intraportal transplantation in ascorbic acid (AsA) biosynthetic enzyme-deficient (ODS-od/od) rats that die of osteogenic disorders unless there is AsA supplementation. HSS was extracted from regenerating porcine livers. Hepatocytes isolated from the livers of congeneic ODS-+/+ rats that are capable of synthesizing AsA were transplanted into the spleen (Sp-HTx) and/or the portal vein (Pv-HTx) of ODS-od/od rats. The recipients were divided into eight groups as follows: HSS-untreated groups [group Ia, sham-operated, HTx(-); group IIa, Sp-HTx; group IIIa, Pv-HTx; and group IVa, Sp- and Pv-HTx], HSS-treated groups [group Ib, HSS only; group IIb, Sp-HTx + HSS; group IIIb, Pv-HTx + HSS; and group IVb, Sp- and Pv-HTx + HSS]. The recipients were given a diet and water containing AsA for 6 weeks after HTx, and AsA supplementation was then halted. The average bromodeoxyuridine (BrdU) labeling index (LI) and hepatocyte-occupied ratio in the spleen (H/S ratio) of HSS-treated rats were significantly higher than those of HSS-untreated rats. All the rats in HSS-untreated groups and group Ib died by 8 weeks after the cessation of AsA. In HSS-treated groups IIb, IIIb, and IVb, the survival rates were 60%, 50%, and 80%, respectively, at 16 weeks after HTx. The average serum AsA level of the surviving rats in groups IIb, IIIb, and IVb was significantly higher than that in HSS-untreated groups. These results indicate that HSS treatment induced rapid proliferation of transplanted hepatocytes in the spleen and the portal vein, and that these proliferating hepatocytes synthesized AsA and improved the survival rate of ODS-od/ od rats.