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BiFe(1-x)Co(x)O3 and Bi0.9Sm0.1Fe(1-x)Co(x)O3 were synthesized under a high pressure of 4 GPa; 10% Sm substitution for Bi in BiFe(1-x)Co(x)O3 (x ≤ 0.20) drastically destabilized the ferroelectric BiFeO3-type structure and changed it to an antiferroelectric PbZrO3-type superstructure. In comparison, a ferroelectric BiCoO3-type tetragonal structure (x ≥ 0.40) was insensitive to the Sm substitution. No decrease in the ferroelectric Curie temperature (TC) was observed. Weak ferromagnetism with a spontaneous moment of 0.025 µB/formula unit (f.u.) was observed for BiFe(1-x)Co(x)O3 (x = 0.10 and 0.20) samples, suggesting the change in the spin structure from a cycloidal one. Because of the coexistence of ferroelectricity and ferromagnetism at room temperature, this compound is a promising multiferroic material.

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We have investigated the role of the Ti-O Coulomb repulsions in the appearance of the ferroelectric state in BaTiO3 as well as the role of the Zn-O Coulomb repulsions in BiZn0.5Ti0.5O3, using a first-principles calculation with optimized structures. In tetragonal BaTiO3, it is found that the Coulomb repulsions between Ti 3s and 3p states and O 2s and 2p states have an important role for the appearance of Ti ion displacement. In BiZn0.5Ti0.5O3, on the other hand, the stronger Zn-O Coulomb repulsions, which are due to the 3s, 3p, and 3d (d10) states of the Zn ion, have more important role than the Ti-O Coulomb repulsions for the appearance of the tetragonal structure. Our suggestion is consistent with the other ferroelectric perovskite oxides ABO3 in the appearance of tetragonal structures as well as rhombohedral structures.

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We performed comparative proteomic analyses of pituitary tumor-derived cell lines, and found a new protein, preliminarily called hydrophobestin, which was produced only in somatotrophic cells, MtT/S, but not in non-hormone-producing cells, MtT/E. Hydrophobestin is encoded by the cell growth regulatory gene, Cgr11, which is known to have growth-suppressive potential in several cell lines. We have now sought to investigate the underlying events responsible for cell growth inhibition by hydrophobestin. Immunocytochemisty revealed that hydrophobestin is localized in the Golgi apparatus of MtT/S cells and Cgr11-transfected MtT/E cells. The apparent molecular mass of the protein was determined by Westerm blot analysis of conditioned culture medium of MtT/S cells. Our data show that hydrophobestin is a secretory protein localized in the pituitary gland, adrenal gland, digestive tract, reproductive organs, and kidney. We also found that hydrophobestin promotes compact monolayer cell aggregates in PC12 cells transfected with Cgr11, however, non-transfected, vector- or EF-hand motif-deleted (DeltaEF) Cgr11-transfected PC12 cells cannot form compact cell colonies. An antibody recognizing EF-hand motifs showed strong staining in the intercellular space of both Cgr11-transfected PC12 cells and MtT/S cells (Cgr11-expressing cells). Our data suggest that hydrophobestin-mediated cell adhesion may regulate cell growth through compact cell attachment.

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A pituitary tumor is considered to be composed of a heterogeneous population of hormone-producing endocrine cells, folliculo-stellate (FS) cells, and potential hormone-inactive progenitor cells to maintain a microenvironment such as that in angiogenesis for tumor development cooperatively. However, the system that maintains such a heterogeneous cell population has not been clarified yet. In the present study, we examined the mechanism for maintaining a heterogeneous cell population using two rat cell lines, MtT/S and MtT/E cells, which are known growth hormone (GH)-producing cells, and their progenitor cells, respectively. We found that conditioned medium of MtT/S cells could stimulate the growth of MtT/E cells. In addition, GH and insulin-like growth factor I (IGF-I) stimulated the growth of MtT/E cells. The messenger RNAs (mRNAs) of receptors for IGF-I and GH were expressed in the MtT/E cells. Moreover, IGF-I receptor inhibitor AG1024 could abolish the growth stimulatory activity in the conditioned medium of MtT/S cells. Therefore, we concluded that somatotropes (MtT/S) maintain their progenitor cells (MtT/E) through the GH-IGF-I signaling and IGF-I directly, which might be involved in the maintenance of progenitors of GH-producing cells and might contribute to pituitary tumor development.

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The tissue distribution of Cu/Zn- and Mn-superoxide dismutases (SOD) in adrenal tumors was studied by an immunohistochemical technique, and the concentrations of both SODs were measured by a sensitive sandwich enzyme immunoassay technique. In the normal adrenal gland, both Cu/Zn- and Mn-SODs were localized predominantly in the reticular zone of the cortex. Cu/Zn-SOD was stained clearly in the inner fascicular zone of the cortex, but not in the medulla, whereas Mn-SOD was stained weakly in the medulla. In different adrenal tumors, the localization of both stained SODs reflected the origin of the tumor cell. Thus, in one section of a pheochromocytoma only Mn-SOD was stained clearly. The concentrations of both SODs in the tissues of medullary tumors were lower than those in the normal adrenal gland and adrenocortical adenomas. The concentration of Cu/Zn-SOD in the tumor tissue of Cushing's syndrome adenoma was higher, and that of Mn-SOD was lower than the concentrations in the normal adrenal gland. The ratio of the tissue concentrations of Mn-SOD to Cu/Zn-SOD was lower in adrenal medullary tumors and Cushing's syndrome adenomas than in the normal adrenal gland and primary aldosteronism adenomas, indicating the predominance of Cu/Zn-SOD in the former, and Mn-SOD in the latter. These data suggest that the localization of Cu/Zn- and Mn-SODs in adrenal tissues reflects the specificity of the adrenal cells that produce the tissue-specific hormones. An investigation of changes in these enzymes in adrenal tumors may also provide useful information on adrenal tumor cell differentiation.

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Duodenum-preserving pancreatic head resection with preservation of the bile duct or without, has been performed in cases of benign or low-grade malignancies, such as intraductal papillary tumors, of the head of the pancreas. However, the selection of the patients, the area of resection in the head of the pancreas, and the operative procedures for the preservation of the pancreaticoduodenal vessels has not been realized among surgeons to apply duodenum-preserving pancreatic head resection as a radical treatment of intraductal papillary tumors. In our experience, duodenum-preserving pancreatic head resection can be applied in the majority of the patients with the branch type of intraductal papillary tumors, and it is necessary to resect completely the head of the pancreas to avoid tumor remnant and pancreatic fistula from the remaining pancreatic rim. Therefore, we modified it to include a total resection of the pancreatic head and the preservation of both anterior and posterior arterial arcades, due to the multiformity of the location of the tumor, the variation of the branch duct in the head of the pancreas, the closure of the minor papilla in some patients, and the unbalanced development of the arterial arcades of the pancreaticoduodenal region. We performed a duodenum-preserving total pancreatic head resection with preservation of the bile duct and the both anterior- and posterior-arterial arcades for 6 patients with the normal gland involving intraductal papillary tumors. The blood flow in this organ was based on the blood supply from both preserved arterial arcades, and the duodenum had retained good color, and the postoperative results were satisfactory.

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BACKGROUND/AIMS: When an Appleby operation is performed for pancreatic body and tail carcinoma, it is necessary for prevention of hepatic ischemia to estimate accurately the hepatic circulation after resection of the celiac artery, the common hepatic artery and the portal vein. We studied the hepatic circulation by monitoring the ShvO2 (hepatic venous hemoglobin oxygen saturation) during an Appleby operation. METHODOLOGY: We performed an Appleby operation on 8 patients with pancreatic cancer. In 6 of 8 patients, a 7-Fr fiberoptic flow direct catheter was inserted in the right hepatic vein. The ShvO2 values were monitored continuously during surgery. RESULTS: The ShvO2 value was 76 +/- 3.5% just after laparotomy, and reduced to 61 +/- 13.2% after clamping the common hepatic artery. The values of the ShvO2 returned to 70.8 +/- 10.9% one hour after clamping. But, one patient underwent reconstruction of the common hepatic artery, because the ShvO2 value still stood at 50%. Combined resection of the portal vein was performed in 5 out of 8 patients. Two patients underwent resection of the portal vein without reconstruction due to the development of the collateral vein, one patients; resection of the portal vein with reconstruction, and two patients; wedge resection. In all 5 patients, the ShvO2 was stable during resection of the portal vein. CONCLUSIONS: Monitoring the ShvO2 is a useful method to evaluate at real time the hepatic circulation during the Appleby operation, and to decide if reconstruction of the common hepatic artery or the portal vein is needed or not.

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The enantiomeric resolution of N-t-butyloxycarbonyl (N-t-Boc) amino acids D/L isomers by reversed-phase HPLC was investigated using cyclodextrins (CD's) as chiral selectors for the mobile phase. The use of a low pH (pH<4) for the mobile phase enabled the enantioseparation of N-t-Boc amino acids. The opposite elution order of D/L isomers was observed when hydroxypropyl-derivatized beta-CD was used instead of native beta-CD. A computer simulation of the enantioseparation showed that the ratio of the retention factors of the chiral selector and the sample determined the elution order and the resolution. When the retention factor of the chiral selector is smaller than that of the sample, an isomer having larger complex formation constant eluted faster. However, when the chiral selector had a larger retention factor than the sample, an opposite elution order of the isomers was obtained. The large difference in the retention factors between the chiral selector and the sample led to good enantiomeric separation.

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