Material Design of Porous Hydroxyapatite Ceramics via Inverse Analysis of an Estimation Model for Bone-Forming Ability Based on Machine Learning and Experimental Validation of Biological Hard Tissue Responses

Hydroxyapatite and β-tricalcium phosphate have been clinically applied as artificial bone materials due to their high biocompatibility. The development of artificial bones requires the verification of safety and efficacy through animal experiments; however, from the viewpoint of animal welfare, it is necessary to reduce the number of animal experiments. In this study, we utilized machine learning to construct a model that estimates the bone-forming ability of bioceramics from material fabrication conditions, material properties, and in vivo experimental conditions. We succeeded in constructing two models: 'Model 1', which predicts material properties from their fabrication conditions, and 'Model 2', which predicts the bone-formation rate from material properties and in vivo experimental conditions. The inclusion of full width at half maximum (FWHM) in the feature of Model 2 showed an improvement in accuracy. Furthermore, the results of the feature importance showed that the FWHMs were the most important. By an inverse analysis of the two models, we proposed candidates for material fabrication conditions to achieve target values of the bone-formation rate. Under the proposed conditions, the material properties of the fabricated material were consistent with the estimated material properties. Furthermore, a comparison between bone-formation rates after 12 weeks of implantation in the porcine tibia and the estimated bone-formation rate. This result showed that the actual bone-formation rates existed within the error range of the estimated bone-formation rates, indicating that machine learning consistently predicts the results of animal experiments using material fabrication conditions. We believe that these findings will lead to the establishment of alternative animal experiments to replace animal experiments in the development of artificial bones.

Catalyst Design and Feature Engineering to Improve Selectivity and Reactivity in Two Simultaneous Cross-Coupling Reactions

Highly active catalysts are required in numerous industrial fields; therefore, to minimize costs and development time, catalyst design using machine learning has attracted significant attention. This study focused on a reaction system where two types of cross-coupling reactions, namely, Buchwald-Hartwig type cross-coupling (BHCC) and Suzuki-Miyaura type cross-coupling (SMCC) reactions, occur simultaneously. Constructing a machine-learning model that considers all experimental conditions is essential to accurately predict the product yield for both the BHCC and the SMCC reactions. The objective of this study was to establish explanatory variables x that considered all experimental conditions within the reaction system involving simultaneous cross-couplings and to design catalysts that achieve the target yield and the development of novel reactions. To accomplish this, Bayesian optimization was combined with established variables x to design new catalysts and enhance reaction selectivity. Moreover, the catalyst design in this study successfully pioneered new reactions involving Cu, Rh, and Pt catalysts in a reaction system that did not previously react with transition metals other than Ni or Pd.

GW501516 acts as an efficient PPARα activator in the mouse liver

The peroxisome proliferator-activated receptor (PPAR) subtype specificity of GW501516, a well-known PPARδ-specific agonist, was studied by examining its effects on the expression of endogenous genes in primary hepatocytes and the liver of wild-type and PPARα-null mice. GW501516, like the PPARα-specific agonist Wy14,643, induced the expression of several PPAR target genes in a dose-dependent manner but this action was mostly absent in the cells and liver of PPARα-null mice. Results indicated that GW501516 acts as an efficient PPARα activator in the mouse liver.

Expression of resistin in the adipose tissue is modulated by various factors including peroxisome proliferator-activated receptor alpha

AIM

Resistin has been suggested to link obesity to diabetes by antagonizing insulin action. However, this model is based on limited observations and how resistin links the two complex processes is not known. In this study, we investigated the effects of various factors on the expression of resistin and examined the generality of the proposal.

METHODS

Total RNA was isolated from the adipose tissues of lean, obese and peroxisome proliferator-activated receptor (PPAR)alpha-null mice fed a control diet or that contained a PPAR ligand, and analysed by Northern blotting using cDNAs for resistin, leptin, aP2 and other mRNAs as probes. For quantitative analysis, an image analyser was used.

RESULTS

Basal expression of resistin mRNA was suppressed by obesity, but the extent of suppression differed significantly among the mouse strains and types of adipose tissue examined. Anti-diabetic thiazolidinediones induced resistin expression in the lean mice and showed smaller effects in obese mice. Furthermore, PPARalpha was shown to play an important role in constitutive expression of resistin in the adipose tissue.

CONCLUSION

Our results indicated that diverse factors modulate the expression of resistin in the adipose tissues of mice, and suggested that resistin is not a master hormone linking obesity to diabetes.

The mechanisms by which both heterozygous peroxisome proliferator-activated receptor gamma (PPARgamma) deficiency and PPARgamma agonist improve insulin resistance

Peroxisome proliferator-activated receptor (PPAR) gamma is a ligand-activated transcription factor and a member of the nuclear hormone receptor superfamily that is thought to be the master regulator of fat storage; however, the relationship between PPARgamma and insulin sensitivity is highly controversial. We show here that supraphysiological activation of PPARgamma by PPARgamma agonist thiazolidinediones (TZD) markedly increases triglyceride (TG) content of white adipose tissue (WAT), thereby decreasing TG content of liver and muscle, leading to amelioration of insulin resistance at the expense of obesity. Moderate reduction of PPARgamma activity by heterozygous PPARgamma deficiency decreases TG content of WAT, skeletal muscle, and liver due to increased leptin expression and increase in fatty acid combustion and decrease in lipogenesis, thereby ameliorating high fat diet-induced obesity and insulin resistance. Moreover, although heterozygous PPARgamma deficiency and TZD have opposite effects on total WAT mass, heterozygous PPARgamma deficiency decreases lipogenesis in WAT, whereas TZD stimulate adipocyte differentiation and apoptosis, thereby both preventing adipocyte hypertrophy, which is associated with alleviation of insulin resistance presumably due to decreases in free fatty acids, and tumor necrosis factor alpha, and up-regulation of adiponectin, at least in part. We conclude that, although by different mechanisms, both heterozygous PPARgamma deficiency and PPARgamma agonist improve insulin resistance, which is associated with decreased TG content of muscle/liver and prevention of adipocyte hypertrophy.

Inhibition of RXR and PPARgamma ameliorates diet-induced obesity and type 2 diabetes

PPARgamma is a ligand-activated transcription factor and functions as a heterodimer with a retinoid X receptor (RXR). Supraphysiological activation of PPARgamma by thiazolidinediones can reduce insulin resistance and hyperglycemia in type 2 diabetes, but these drugs can also cause weight gain. Quite unexpectedly, a moderate reduction of PPARgamma activity observed in heterozygous PPARgamma-deficient mice or the Pro12Ala polymorphism in human PPARgamma, has been shown to prevent insulin resistance and obesity induced by a high-fat diet. In this study, we investigated whether functional antagonism toward PPARgamma/RXR could be used to treat obesity and type 2 diabetes. We show herein that an RXR antagonist and a PPARgamma antagonist decrease triglyceride (TG) content in white adipose tissue, skeletal muscle, and liver. These inhibitors potentiated leptin's effects and increased fatty acid combustion and energy dissipation, thereby ameliorating HF diet-induced obesity and insulin resistance. Paradoxically, treatment of heterozygous PPARgamma-deficient mice with an RXR antagonist or a PPARgamma antagonist depletes white adipose tissue and markedly decreases leptin levels and energy dissipation, which increases TG content in skeletal muscle and the liver, thereby leading to the re-emergence of insulin resistance. Our data suggested that appropriate functional antagonism of PPARgamma/RXR may be a logical approach to protection against obesity and related diseases such as type 2 diabetes.

PPAR-mediated diverse responses in various tissues of mouse

Peroxisome proliferator-activated receptors (PPARs) play the essential role in transcriptional modulations of the genes involved in lipid metabolism. In vitro studies have shown that all the mechanisms of the modulations are similarly mediated by PPAR and the response elements through heterodimerization with retinoid X receptors (RXRs). However, PPARs mediate the diverse effects induced in various tissues of mouse by their activators. First, PPAR alpha also plays an obligatory role in the activator-induced transcriptional modulations of various genes, some of which are not related to lipid metabolism. Second, responsiveness of various genes to several activators varies considerably. Third, some of the activator-induced transcriptional activation of several genes is strictly tissue-specific. Fourth, the time courses of the activator-induced transcriptional modulations are diverse. Following brief review of these diverse responses, emphasis is laid on the need for studies of these diversely regulated genes to understand the species-general and coordinated interplay between PPARs and other factors to maintain lipid homeostasis at the body level.

Relationship between signal transduction and PPAR alpha-regulated genes of lipid metabolism in rat hepatic-derived Fao cells

The goal of this study was to characterize phosphorylated proteins and to evaluate the changes in their phosphorylation level under the influence of a peroxisome proliferator (PP) with hypolipidemic activity of the fibrate family. The incubation of rat hepatic derived Fao cells with ciprofibrate leads to an overphosphorylation of proteins, especially one of 85 kDa, indicating that kinase (or phosphatase) activities are modified. Moreover, immunoprecipitation of 32P-labeled cell lysates shows that the nuclear receptor, PP-activated receptor, alpha isoform, can exist in a phosphorylated form, and its phosphorylation is increased by ciprofibrate. This study shows that PP acts at different steps of cell signaling. These steps can modulate gene expression of enzymes involved in fatty acid metabolism and lipid homeostasis, as well as in detoxication processes.

Technique for calculation of the propagation constant in an optical planar waveguide with a gaussian profile

We performed analysis of a planar waveguide with arbitrary index variations. We obtained numerical results for the propagation coefficient by using first-order Langer and Liouville transformations. The accuracy of the numerical results is confirmed by a comparison with those obtained by other methods.

[Suppression of stress proteins, GRP78, GRP94, calreticulin and calnexin in liver endoplasmic reticulum of rat treated with a highly toxic coplanar PCB]

The present study was addressed on the effect of 3,3',4,4',5-pentachlorobiphenyl (PenCB) to the expression of molecular chaperon proteins, glucose regulated protein (GRP) 78, GRP94, calreticulin and calnexin in liver endoplasmic reticulum of rat by treatment with acute exposure. Male Wistar rats received PenCB in corn oil at once a dose of 10 mg/kg i.p., then at 5 days after treatment the microsomes were prepared. Free-fed and pair-fed control groups were given the vehicle. The microsomal proteins were separated on SDS-PAGE, transferred to membrane and blotted using antibody towards respective chaperone proteins. The protein levels of GRP78, GRP94, calreticulin and calnexin were significantly decreased with the acute exposure. In addition, albumin level in the microsomes was also significantly reduced by the PenCB treatment. The transferrin level was significantly higher than pair-fed but not from free-fed group. These chaperone proteins have important physiological functions against synthesized and/or denatured proteins, which include assembling, folding of proteins. PenCB-treatment may alter the extent of biosynthesis of secretory protein such as albumin through the decreasing levels of chaperone proteins in endoplasmic reticulum. Interestingly, reduced GRP78 protein level by PenCB was not due to decreased mRNA level. Our results suggested that a part of the toxicity of PenCB is associated to significant decrease of the chaperone proteins in the endoplasmic reticulum.

A half-type ABC transporter TAPL is highly conserved between rodent and man, and the human gene is not responsive to interferon-gamma in contrast to TAP1 and TAP2

TAPL is a half-type ABC transporter with sequence similarity to TAP1 and TAP2 that is transcribed in various rat tissues [Yamaguchi, Y., Kasano, M., Terada, T., Sato, R., and Maeda, M. (1999) FEBS Lett. 457, 231-236]. Primary structures of the human and mouse orthologous counterparts were deduced from cDNAs cloned by means of polymerase chain reaction, and they were compared with that of the rat. The mammalian TAPLs (rat, mouse, and human) are highly conserved, since about 95% of the amino acid residues are identical between rodents and man. Phylogenetic analysis demonstrated that the evolutional rate of TAPL is much slower than those of TAP1 and TAP2, although TAPL could have diverged from an ancestor of TAP1 or that of TAP1 and TAP2. The TAPL-GFP fusion protein transiently expressed in Cos-1 cells was co-localized with PDI, suggesting that TAPL is inserted into endoplasmic reticulum membrane. The conservation of the peptide-binding motifs of TAP proteins in TAPL raises the possibility that the TAPL might be a peptide transporter. The gene for human TAPL is assigned to chromosome 12q24.31-q24.32, while those for TAP1 and TAP2 are located at the MHC locus of chromosome 6p21.!3. Furthermore, the transcription of TAPL gene is not responsive to interferon-gamma, in contrast to TAP1 and TAP2. These results indicate that the gene regulation of TAPL is different from those of TAP1 and TAP2.

Differential effects of PPARalpha activators on induction of ectopic expression of tissue-specific fatty acid binding protein genes in the mouse liver

The effect of a potent peroxisome proliferator-activated receptor (PPAR) alpha activator Wy14,643 on tissue-specific expression of fatty acid binding (FABP) genes was studied. Wy14,643 immediately induced liver-, intestine- and FABP but not PPARgamma-regulated adipose-FABP (or aP2) mRNAs in respective mouse tissues. Moreover, it gradually induced ectopic expression of heart- and adipose-FABP mRNAs to significant levels in the liver. However, ectopic expression was not induced in the liver of PPARalpha-null mouse, indicating an obligatory role of the receptor in the modulated expression. Among the four PPARalpha activators examined, only Wy14,643 induced ectopical expression of heart-FABP in the liver. Thus, tissue-specificity of the FABP gene expression is not absolute and, with a potent activator, can be distorted by PPARalpha.

Insulin-degrading enzyme exists inside of rat liver peroxisomes and degrades oxidized proteins

Insulin-degrading enzyme (IDE) was detected by immunoblot analysis in highly purified rat liver peroxisomes. IDE in the peroxisomal fraction was resistant to proteolysis by trypsin and chymotrypsin under conditions where the peroxisomal membranes remained intact. After sonication of the peroxisomal fraction, IDE was recovered in the supernatant fraction. Further, the localization of IDE in the peroxisomes was shown by immunoelectron microscopy. In addition, IDE isolated from peroxisomes degraded insulin as well as oxidized lysozyme as a model substrate for oxidized proteins. These results suggest that IDE exists in an active form in the matrix of rat liver peroxisomes and is involved in elimination of oxidized proteins in peroxisomes.

Ciprofibrate stimulates protein kinase C-dependent phosphorylation of an 85 kDa protein in rat Fao hepatic derived cells

The effect of ciprofibrate on early events of signal transduction was previously studied in Fao cells. Protein kinase C (PKC) assays performed on permeabilized cells showed a more than two-fold increase in PKC activity in cells treated for 24 h with 500 microM ciprofibrate. To show the subsequent effect of this increase on protein phosphorylation, the in vitro phosphorylation on particulate fractions obtained from Fao cells was studied. Among several modifications, the phosphorylation of protein(s) with an apparent molecular mass of 85 kDa was investigated. This modification appeared in the first 24 h of treatment with 500 microM ciprofibrate. It was shown to occur on Ser/Thr residue(s). It was calcium but not calmodulin-dependent. The phosphorylation level of this/these protein(s) was reduced with kinase inhibitors and especially with 300 nM GF-109203X, a specific inhibitor of PKC. All these results suggest that the phosphorylation of the 85 kDa protein(s) is due to a PKC or to another Ser/Thr kinase activated via a PKC pathway. A possible biochemical candidate for 85 kDa protein seems to be the beta isoform of phosphatidylinositol 3-kinase regulatory subunit.

A new thiazolidinedione, NC-2100, which is a weak PPAR-gamma activator, exhibits potent antidiabetic effects and induces uncoupling protein 1 in white adipose tissue of KKAy obese mice

Thiazolidinediones (TZDs) reduce insulin resistance in type 2 diabetes by increasing peripheral uptake of glucose, and they bind to and activate the transcriptional factor peroxisome proliferator-activated receptor-gamma (PPAR-gamma). Studies have suggested that TZD-induced activation of PPAR-gamma correlates with antidiabetic action, but the mechanism by which the activated PPAR-gamma is involved in reducing insulin resistance is not known. To examine whether activation of PPAR-gamma directly correlates with antidiabetic activities, we compared the effects of 4 TZDs (troglitazone, pioglitazone, BRL-49653, and a new derivative, NC-2100) on the activation of PPAR-gamma in a reporter assay, transcription of the target genes, adipogenesis, plasma glucose and triglyceride levels, and body weight using obese KKAy mice. There were 10- to 30-fold higher concentrations of NC-2100 required for maximal activation of PPAR-gamma in a reporter assay system, and only high concentrations of NC-2100 weakly induced transcription of the PPAR-gamma but not PPAR-alpha target genes in a whole mouse and adipogenesis of cultured 3T3L1 cells, which indicates that NC-2100 is a weak PPAR-gamma activator. However, low concentrations of NC-2100 efficiently lowered plasma glucose levels in KKAy obese mice. These results strongly suggest that TZD-induced activation of PPAR-gamma does not directly correlate with antidiabetic (glucose-lowering) action. Furthermore, NC-2100 caused the smallest body weight increase of the 4 TZDs, which may be partly explained by the finding that NC-2100 efficiently induces uncoupling protein (UCP)-2 mRNA and significantly induces UCP1 mRNA in white adipose tissue (WAT). NC-2100 induced UCP1 efficiently in mesenteric WAT and less efficiently in subcutaneous WAT, although pioglitazone and troglitazone also slightly induced UCP1 only in mesenteric WAT. These characteristics of NC-2100 should be beneficial for humans with limited amounts of brown adipose tissue.

Expression of putative fatty acid transporter genes are regulated by peroxisome proliferator-activated receptor alpha and gamma activators in a tissue- and inducer-specific manner

Regulation of gene expression of three putative long-chain fatty acid transport proteins, fatty acid translocase (FAT), mitochondrial aspartate aminotransferase (mAspAT), and fatty acid transport protein (FATP), by drugs that activate peroxisome proliferator-activated receptor (PPAR) alpha and gamma were studied using normal and obese mice and rat hepatoma cells. FAT mRNA was induced in liver and intestine of normal mice and in hepatoma cells to various extents only by PPARalpha-activating drugs. FATP mRNA was similarly induced in liver, but to a lesser extent in intestine. The induction time course in the liver was slower for FAT and FATP mRNA than that of an mRNA encoding a peroxisomal enzyme. An obligatory role of PPARalpha in hepatic FAT and FATP induction was demonstrated, since an increase in these mRNAs was not observed in PPARalpha-null mice. Levels of mAspAT mRNA were higher in liver and intestine of mice treated with peroxisome proliferators, while levels in hepatoma cells were similar regardless of treatment. In white adipose tissue of KKAy obese mice, thiazolidinedione PPARgamma activators (pioglitazone and troglitazone) induced FAT and FATP more efficiently than the PPARalpha activator, clofibrate. This effect was absent in brown adipose tissue. Under the same conditions, levels of mAspAT mRNA did not change significantly in these tissues. In conclusion, tissue-specific expression of FAT and FATP genes involves both PPARalpha and -gamma. Our data suggest that among the three putative long-chain fatty acid transporters, FAT and FATP appear to have physiological roles. Thus, peroxisome proliferators not only influence the metabolism of intracellular fatty acids but also cellular uptake, which is likely to be an important regulatory step in lipid homeostasis.

Peroxisome proliferator-activated receptor (PPAR)-dependent and -independent transcriptional modulation of several non-peroxisomal genes by peroxisome proliferators

To better characterize peroxisome proliferator-induced non-peroxisomal responses, we searched the mRNAs of which the levels were modulated by proliferators. We used the PCR-based methods including differential display. The mRNAs were divided into at least four groups by their time-courses of induction and repression: group 1 very rapidly increased then decreased; group 2 increased after a time lag (well-characterized peroxisomal mRNAs belonged to this group); group 3 decreased reciprocally compared with group 2 mRNAs; group 4 increased after group 2 mRNAs, with a much longer lag period. All of these modulations cannot be explained by peroxisome proliferator action through PPAR and RXR dimerization on the target genes to activate transcription. Another unidentified transcription factor may be involved in some of these modulations. It will also be important to consider PPAR-independent pathways when studying the diverse effects of peroxisome proliferators.

PPAR alpha mediates peroxisome proliferator-induced transcriptional repression of nonperoxisomal gene expression in mouse

The strain difference, peroxisome proliferator specificity and role of PPAR alpha in peroxisome proliferator-induced transcriptional repression of nonperoxisomal transthyretin and alpha2u-globulin genes were examined. The genes were repressed by four peroxisome proliferators in all seven mouse strains tested. The extent of repression was strongly dependent on both the mouse strains and type of proliferator, although the mRNA levels of PPAR alpha and its partner in heterodimerization, RXR alpha were not different. The role of PPAR alpha in repression was confirmed by the finding that PPAR alpha-null mice were not responsive to transcriptional repression. These results indicate that PPAR alpha plays an obligatory role in transcription of various genes, some of which are not related to lipid metabolism.

Insulinoma: correlation of short-TI inversion-recovery (STIR) imaging and histopathologic findings

We studied the value of short-TI inversion-recovery (STIR) imaging for the localization of pancreatic insulinoma. Four patients (three women and one man aged 35-65 years) with surgically proven insulinoma were included in this study. All patients were examined by MR imaging with spin echo (SE) and STIR sequences. The STIR images were compared with the histopathologic findings in each case. In two patients, the tumors were markedly hyperintense on STIR images, and a 5-mm insulinoma was depicted only by this imaging method in one of the two. In the other two patients, 10-mm insulinomas were only slightly hyperintense on STIR images. The latter tumors had a higher content of collagen fibers than the former, indicating that the amount of collagen influences the signal intensity of insulinoma. Despite some limitations, STIR imaging is a useful noninvasive method for the localization of pancreatic insulinoma.

Expression of epidermal growth factor receptor messenger RNA in human colorectal carcinomas assessed by non-radioactive in-situ hybridization

No consensus as to the involvement of the epidermal growth factor receptor (EGF-R) in colorectal carcinomas has yet been attained, although they are assumed to play a role in the metastasis to lymph nodes and recurrence of breast carcinoma and bladder carcinoma invasion. Knowing that Dukes' classification of colorectal carcinoma is closely related to prognosis, we examined whether there is a correlation between Dukes' classification and the expression of EGF-R in colorectal carcinoma. If there is a positive correlation, the involvement of EGF-R in the processes may be assumed and the expression of EGF-R may be used as a marker of their prognosis. To this end, the expression of EGF-R mRNA and protein by non-radioactive in-situ hybridization and immunohistochemistry, respectively, were determined on histological preparations of formalin-fixed paraffin-embedded colorectal surgical specimens. In 30 cases of colorectal carcinoma examined, mRNA and/or protein was detected in 33% (two of six) of Dukes' A, in 40% (four of 10) of Dukes' B, in 36% (four of 11) of Dukes' C, in 33% (one of three) of Dukes' D and in 0% of normal colon epithelial cells. Thus, there was no positive correlation between the Dukes' classification and the expression of EGF-R. It is concluded that the expression of EGF-R in colorectal carcinoma is not a promising marker of prognosis. However, the role of EGF-R in EGF-R positive tumours remains to be examined.

Effective treatment of liver metastases from colon cancer with a combination of gamma-interferon and cisplatin chemotherapy: report of a case

We report herein the case of a 63-year-old man with cancer of the sigmoid colon and metastatic nodules in the liver who was effectively treated with a combination of cisplatin regional chemotherapy, given through the hepatic artery, in conjunction with a 3-week course of intravenous gamma-interferon (INF-gamma), following palliative sigmoidectomy and dissection of the regional lymph nodes. This was followed-up by a 3-month course of oral 5-fluorouracil. Hepatic imaging performed 6 months postoperatively showed no masses in the right hepatic lobe and an apparent decrease in the size of the tumor in the left lobe. A second-look operation with resection performed at this time confirmed the efficacy of the chemotherapy. The patient survived in excess of 30 months following his initial surgery before succumbing to hepatic failure.

Characterization of serum proteins down-regulated by peroxisome proliferators: transient repression of apoE gene expression in the rat liver

The effects of peroxisome proliferators on the levels of rat serum proteins were examined. The proliferators reduced the levels of several proteins in various ways with respect to proliferator-specificity and the time courses of the changes. The identification of three proteins by amino acid sequencing showed that they were functionally unrelated. This diversity suggests that several primary and secondary effects of the peroxisome proliferators caused the various changes in the levels of several serum proteins. Among these, apolipoprotein E was the most but transiently down-regulated by the two proliferators tested. Northern blots of the rat liver mRNA suggested that the primary step of the down-regulation was at pre-translation.

Transient induction of fatty acid synthase in rat liver after removal of a peroxisome proliferator

Removal of a peroxisome proliferator from the diet triggered the degradation of peroxisomes and induced the transient expression of a 220 kDa soluble protein in rat liver. The 220 kDa protein was purified by conventional methods and analyzed by amino acid sequencing. A total of 99 amino acid residues in 4 lysylendopeptidase-digested peptides completely matched those in rat fatty acid synthase. The transient induction of fatty acid synthase mRNA during peroxisome degradation was confirmed by Northern blotting.

Histidyl phosphorylation of P36 in rat hepatoma Fao cells in vitro and in vivo

We have previously shown that a membrane-associated P36 from rat liver was in vitro phosphorylated at His residue(s) with a phosphoric amide bond (FEBS Lett., 319:75-79, 1993), and the activity was solubilized and partially purified (J. Biol. Chem., 269:9030-9037, 1994). The present study demonstrates that the P36 histidyl phosphorylation occurs in rat hepatoma cells under normal conditions. Phosphorylation and dephosphorylation of histidine as well as those of serine, threonine and tyrosine residues may also play an important role in animal cells.

Expression of p53 protein in gastric carcinomas is not independently prognostic

BACKGROUND

Biologic significance of p53 protein expression in gastric carcinomas is unclear. The relationship between p53 expression and survival after curative operations for gastric carcinoma was evaluated.

METHODS

Paraffin-embedded specimens from 135 patients who underwent curative resection of gastric carcinoma were analyzed immunohistochemically for p53 expression.

RESULTS

Immunoreactivity of p53 was found in 37 of 135 gastric tumors. Six of 48 early gastric carcinomas expressed focally scattered p53. Pattern of p53 expression in the majority of advanced carcinomas was diffuse. In univariate analyses a significant relationship with survival was found for tumor size (p < 0.01), depth of invasion (p < 0.01), nodal involvement (p < 0.01), and p53 expression (p < 0.01). Significant relationships were found between p53 expression and nodal involvement (p < 0.01) and depth of invasion (p < 0.01). A multivariate analysis revealed that the independent predictors of recurrence were nodal involvement (p = 0.009) and depth of invasion (p = 0.009). In a logistic multiple regression analysis p53 expression was not independently related to the parameters, which suggests an aggressive tumor.

CONCLUSIONS

Our results suggest that p53 expression did not correlate with the aggressiveness of gastric carcinomas and failed to be an independent predictor of outcome.

Expression of Kirsten-ras p21 in gastric cancer correlates with tumor progression and is prognostic

The purpose of this study was to determine the correlation between expression of ras oncoproteins and the tumor stage or outcome of patients with gastric carcinoma. After the specificity of each anti-ras monoclonal antibody was confirmed by protein immunoblot analysis, immunohistochemical assays for a common-ras antigen present in N-, Harvey- and Kirsten (K)-ras oncoproteins, as well as for K-ras specific antigen, were performed on paraffin-embedded carcinoma tissue from 110 patients who underwent curative resection. By Western blot analysis, there was more p21 in fresh cancer specimens than in normal specimens. K-ras expression distinguished advanced from early gastric carcinoma and correlated with depth of cancer invasion. Among the 110 patients, survival rates of those with carcinomas positive for the common-ras or K-ras antigens were significantly lower than of those with antigen-negative carcinomas (p < 0.05). In a multivariate analysis, nodal involvement (p = 0.002), serosal invasion (p = 0.012) and K-ras p21 expression (p = 0.044) were independently predictive of the recurrence. These results suggest that K-ras p21 is a useful marker of tumor progression and poor prognosis after curative resection.

Histidyl phosphorylation and dephosphorylation of P36 in rat liver extract

Protein histidine kinase (Motojima, K., and Goto, S. (1993) FEBS Lett. 319, 75-79) and phosphatase in rat liver extract were characterized. The histidine kinase was recovered mostly in the membrane and the phosphatase in the soluble fraction. The kinase and its substrate 36-kDa protein (P36) were co-solubilized from the membrane under conditions in which most of the other kinases, and their substrate proteins were not solubilized. The solubilized kinase and P36 were co-eluted after high pressure liquid chromatography gel filtration, showing an apparent molecular mass of 70-75 kDa. They were also co-eluted after ion exchange chromatography. These characteristics, together with its complete resistance to genistein, indicate that the rat liver histidine kinase is not cognate to the yeast enzyme (Huang, J., Nasr, M., Kim, Y., and Matthews, H.R. (1992) J. Biol. Chem. 267, 15511-15515). The phosphatase that dephosphorylates histidyl-phosphorylated P36 was also studied using rat liver subcellular fractions and in vitro phosphorylated P36 as the substrate. The characteristics of the phosphatase, that is, 1) Mg2+ requirement for activity, 2) apparent molecular mass of 45 kDa by high performance liquid chromatography gel filtration, and 3) resistance to 100 microM okadaic acid, suggest that the primary phosphatase active in vitro is protein phosphatase 2C.

erbB-2 expression in well-differentiated adenocarcinoma of the stomach predicts shorter survival after curative resection

BACKGROUND

Correlation between erbB-2 expression, histologic type of gastric carcinoma, and survival after curative resection was evaluated.

METHODS

Paraffin-embedded specimens from 120 patients who underwent curative resection of gastric carcinoma were analyzed immunohistochemically for the expression of erbB-2.

RESULTS

Enhanced erbB-2 expression correlated with tumor stage and depth of invasion. Well-differentiated adenocarcinomas had a higher incidence of erbB-2 expression than did poorly differentiated carcinomas. Survival rates of 33 patients with erbB-2-positive carcinomas were significantly lower than those of 87 with erbB-2-negative carcinomas (p < 0.001). Survival rates of patients with well-differentiated adenocarcinomas that were erbB-2 positive were significantly lower than those that were erbB-2 negative (p < 0.001). However, the presence of erbB-2 was not associated with altered survival in 46 patients with poorly differentiated carcinomas. Multivariate analysis of all 120 patients revealed that independent predictors of recurrent disease include nodal involvement (p = 0.003) and erbB-2 expression (p = 0.0051).

CONCLUSIONS

Our results suggest that erbB-2 expression is a new marker associated with poor prognosis in well-differentiated gastric adenocarcinomas.

The surgical technique of retroperitoneal lavage for the treatment of extended necrotizing pancreatitis

For cases of extended necrotizing pancreatitis which involve the spread of infectious or hemorrhagic necrotic lesions to the retroperitoneal tissue, we recommend sequestrectomy and subsequent retroperitoneal lavage via the retroperitoneal access. For successful retroperitoneal lavage, as much liquefactive infectious necrotic tissue as possible should be removed from the retroperitoneal cavity during the operation. In addition, the necrotic cavity should be opened, adequately washed out, and catheters placed in the retroperitoneal cavity by retroperitoneal access. Although we have only applied this ideal technique in two patients so far, the details are presented herein. The significance of retroperitoneal lavage lies in the fact that it cleans the retroperitoneal foci of infection and necrosis, and that it eliminates the necrotic material, bacterial deposits, and biologically active substances produced after surgery. Ultimately, wound healing is markedly promoted, leading to improvement in the systemic condition.

Increase in the amount of elongation factor 2 in rat liver by peroxisome proliferators

The changes in protein phosphorylation during induction and deinduction of peroxisome proliferation in rat liver by three types of proliferators were studied by in vitro phosphorylation assay. Among the variously phosphorylated proteins, an increase during induction and a decrease during deinduction in phosphorylation of P100, a cytosolic protein having a molecular weight of 100 kDa, was most remarkable. The time course of enhancement of phosphorylation by the administration of the proliferators, however, was not parallel with proliferation of peroxisome but with increase in the liver DNA content. Amino acid sequencing of the protein indicated the identity of its N-terminal 17 amino acid residues with those of elongation factor 2 (EF2). Increase in the amount of EF2 by peroxisome proliferators was confirmed by immunoblotting and this was almost parallel with peroxisome proliferation, suggesting that both increase in the amount of EF2 and some changes in phosphorylation activities account for a large increase in in vitro phosphorylation of EF2 by the administration of peroxisome proliferators.

Peroxisome proliferator-activated receptor (PPAR): structure, mechanisms of activation and diverse functions

The structurally diverse xenobiotic peroxisome proliferators (PPs) increase the number of peroxisomes per cell and the levels of several enzymes, and cause hepatomegaly, often leading to hepatocarcinogenesis in a species- and tissue-specific manner. The deadlocked problems of the molecular mechanism of PP action and its physiological meanings have begun to be understood through cDNA cloning of a PP-activated receptor (PPAR). PPAR, a member of the steroid/thyroid/vitamin superfamily of nuclear receptors, has isoforms and differentially heterodimerizes with other nuclear receptors, providing potential mechanisms not only for species- and tissue-specific actions but also for diverse actions of PPs. Recent findings related to PPAR are summarized, and its possible role in lipid metabolism and involvement in PP-induced hepatocarcinogenesis are discussed.

Solid and cystic tumor of the pancreas occurring without cyst formation in an adult male

A solid and cystic tumor (SCT) of the pancreas occurring in a 35-yr-old male is reported. Cut sections of the specimen revealed a solid, ill-defined mass measuring 2.5 x 2.3 x 2.0 cm, without cystic or necrotic changes. Histologically, the solid tumor consisted of small, round acidophilic cells invading the surrounding pancreatic parenchyma. The tumor cells were positive for alpha-1-antitrypsin and neuron-specific-enolase. Ultrastructural studies revealed clear nuclei with no zymogen, but immature secretory granules in the cytoplasm of the tumor cells, which had a junctional complex-like structure. These findings were consistent with the so-called solid and cystic tumor of the pancreas. There was neither a capsule surrounding the tumor nor a papillary structure, known to be characteristic findings of the SCT tumor. The small tumor reported in the present article might represent an early-stage SCT of the pancreas.

[Surgical treatment of recurrent thyroid carcinoma after primary resection]

Twenty-six patients who underwent the second operation for recurrent thyroid carcinoma were reviewed. 1) Three surgical interventions; dissection of local lymph nodes, modified neck dissection and extended neck dissection, for the patients with recurrent thyroid carcinoma were performed. Among these patients, recurrence of thyroid carcinoma occurred again in 14 (74%) of 19 patients with dissection of local lymph nodes, 15 (63%) of 24 with modified neck dissection, 2 (22%) of 9 with extended neck dissection. Patients with extended neck dissection had significantly less local recurrence than those with other procedures (p < 0.05). 2) Lymph node recurrence on the resected area occurred in 11 (73%) of 14 patients with dissection of local lymph nodes. Ten (67%) of 15 patients with modified neck dissection had recurrence beyond the dissected area. 3) In well differentiated carcinoma, there was recurrence in 5 (62%) of 8 patients with dissection of local lymph nodes, and in 4 (31%) of 13 with modified neck dissection. In contrast, in poorly differentiated carcinoma, we found recurrence in 8 (89%) of 9, and 10 (100%) of 10, respectively. However, in only one (20%) patient with extended neck dissection, recurrence occurred. We conclude that extended neck dissection should be the procedure of choice in patients with recurrent thyroid cancer whenever feasible.

Prevention of insulitis and diabetes in nonobese diabetic mice by administration of FK506

We investigated the preventive effect of the immunosuppressive agent FK506 on autoimmune insulitis in nonobese diabetic mice. The mice were given FK506 in a dose of 1.0 mg/kg, every other day, from age 2 to 12, 2 to 6, and 4 to 12 weeks, respectively; after which, the incidence of insulitis and overt diabetes was monitored. Effects of FK506 on immune reactions to beta cells were also investigated by using both syngeneic and allogeneic islet transplants. Treatment with FK506 in mice from age 2 weeks prevented completely the onset of overt diabetes, and the incidence of insulitis was reduced to less than 10% at age 30 weeks. Treatment of mice with FK506 from age 4 weeks was less effective in preventing insulitis and the onset of diabetes. In case of islet transplantation, FK506 treatment of NOD mice from age 2 to 6 weeks prevented autoimmune responses both in syngeneic islets and in allogeneic islets, which share the same H-2 antigen with the nonobese diabetic mouse. These results also indicate that the recognition of islet antigens and the generation of autoimmune-reactive T lymphocytes start between 2 and 4 weeks of age, and FK506 prevents an autoimmune reaction.

A protein histidine kinase induced in rat liver by peroxisome proliferators. In vitro activation by Ras protein and guanine nucleotides

A novel protein kinase is induced in rat liver plasma membrane by the administration of peroxisome proliferators. A 36 kDa protein (P36) on the membrane was rapidly phosphorylated in vitro by the kinase and the phosphorylated amino acid was identified as phosphohistidine. Histidine phosphorylation of P36 was activated in vitro by recombinant Ras protein and GTP; both decreased Michaelis constant (Km) for ATP from 1.25 to 0.25 microM. The novel histidine kinase, products of which have been overlooked due to their acid lability, may participate in cellular signaling and peroxisome proliferators may perturb the pathway.

Detection of point mutations in the Kirsten-ras oncogene provides evidence for the multicentricity of pancreatic carcinoma

It has been reported that multicentricity of pancreatic carcinomas extending beyond the pancreatic duct occur in 15% to 40% of patients. This has been difficult to confirm, however, with currently available histologic techniques. Mutations in the Kirsten (Ki)-ras oncogene, which can be detected frequently in pancreatic carcinomas using the polymerase chain reaction (PCR), may serve as a potential clonal marker of the cancer cells. Fifty-three patients with a histopathologic diagnosis of pancreatic carcinoma were selected for the determination of certain Ki-ras mutations through PCR. The authors identified mutations in the Ki-ras codon 12 in 46 of 53 tumors. Two of these 46 tumors had two different mutations to aspartic acid (GAT) and to valine (GTT) in Ki-ras codon 12. Another isolate had an additional mutation in Ki-ras codon 13. The detection of different mutations in the same tumor suggests that there may be multicentricity in pancreatic carcinomas and that its frequency may be as low as 6% of the carcinomas. These results imply that total pancreatectomy for eliminating tumor recurrence due to multicentricity may not be warranted.

Bile secretion and histology of liver autotransplanted into the pancreatic parenchyma

The pancreatic parenchyma was evaluated as a potential recipient site for hepatic fragment autotransplantation. Histologic and functional studies of hepatic autografts in the pancreas were performed in 15 mongrel dogs. Approximately 10 g of liver parenchyma was resected from each left lateral lobe. The remnant liver remained in situ. Bile secretion from the hepatic tissues implanted into the pancreas was estimated by measuring the indocyanine green (ICG)* concentration in pancreatic juice following intravenous ICG injection. One month following implantation, the hepatocytes in the pancreatic parenchyma were histologically colorless and did not have sinusoids. However, by the second month following implantation, hepatic nodules had grown extensively to become normal liver tissue, with sinusoids and a single liver cell-plate structure. At 4 months following intrapancreatic implantation the transplanted hepatic masses consisted of several hepatic lobules. Furthermore, ICG could be detected in the pancreatic juice of dogs surviving more than 2 months after implantation but no ICG could be detected in the pancreatic juice of normal controls. The present study provides direct evidence that hepatic grafts transplanted into the pancreas that has a ductal drainage system for bile secretion can reconstitute histologically normal liver tissue capable of secreting bile. This model can be used to understand the early steps of hepatic regeneration.

Specific repression of transthyretin gene expression in rat liver by a peroxisome proliferator clofibrate

The effect of clofibrate, a hypolipidemic drug and a potent peroxisome proliferator, on expression of a nonperoxisomal transthyretin (prealbumin) gene was studied using rats fed clofibrate for various periods. Upon feeding a diet containing clofibrate, the level of transthyretin mRNA was down-regulated, reaching 20% of the control level, in an almost reciprocal time course to that of increases in the levels of peroxisomal mRNAs. Studies on expression of other steroid hormone regulated genes suggest that clofibrate may down-regulate several but not all types of steroid hormone regulated mRNA expression.

[Evaluation of immunoreactivity to erbB-2 protein as a marker of prognosis in bile duct carcinoma]

Recent studies of erbB-2 expression have shown that the erbB-2 oncoprotein correlated with poor prognosis of patients with breast cancer. Surgical treatment of the bile duct carcinoma is currently unsatisfactory. To evaluate erbB-2 oncoprotein as a marker of prognosis, we analyzed 68 bile duct carcinomas immunohistologically, using monoclonal antibody against erbB-2 oncoprotein, as well as clinicopathological data and outcome. High incidence of expression of erbB-2 oncoprotein was shown in bile duct carcinoma. Positive rates of erbB-2 oncoprotein correlated with stage of bile duct carcinoma. Survival of patients with erbB-2 expression cancer was shorter than those without erbB-2 expression cancer and erbB-2 expression has a prognostic value in bile duct carcinoma.

Rat liver BiP/GRP78 is down-regulated by a peroxisome-proliferator, clofibrate

Administration of clofibrate in rat results in down-regulation of several liver proteins and a vast induction of peroxisomal proteins. One protein was identified as BiP/GRP78 using antibodies and cDNA cloning. The level of mRNA was reduced by the drug.

Molecular cloning of a rat liver cDNA encoding the 16 kDa subunit of vacuolar H(+)-ATPases: organellar and tissue distribution of 16 kDa proteolipids

A cDNA (T3-L) encoding the 16 kDa subunit of vacuolar H(+)-ATPase was cloned from a cDNA library of rat liver. A polypeptide of 155 amino acids with a molecular mass of 15,807 Da (pI = 9.5) having four hydrophobic stretches was predicted. T3-L polypeptide was 92% and 100% identical with the 16 kDa proteolipid of bovine chromaffin granule and that of mouse, respectively. Antisera raised against the NH2-terminal of the T3-L polypeptide reacted positively with the membrane ghosts of rat liver tritosomes and the partially purified H(+)-ATPase thereof. Western blotting of subcellular fractions with the antisera showed high abundance of 16 kDa protein in the lysosomes, although a significant amount was also detected in the Golgi apparatus. Western blotting of rat tissues revealed high levels of 16 kDa proteolipid in the brain and the kidney. Northern blots with T3-L similarly showed considerably high expression of T3-L mRNA in the brain and the kidney. Southern hybridization of rat genomic DNA with T3-L showed at most three distinct bands, regardless of the stringency of hybridization and whether hybridization was performed with its subfragments. This suggests the possibility of multiple (at least three) homologous/identical genes encoding 16 kDa proteolipid. The possible presence and significance of isoforms of 16 kDa proteolipid in rats are discussed.

A multi-institute case-control study on the risk factors of developing pancreatic cancer

A multi-institute, hospital-based, case-control study on pancreatic cancer was carried out to examine its association with preceding diseases, cigarette smoking, alcohol drinking and dietary factors. Analyses were based on 124 newly diagnosed exocrine pancreatic cancer cases and sex-, age- and institute-matched hospital controls in seven hospitals in Japan. Cigarette smoking showed a positive association with the risk of developing pancreatic cancer. Especially among smokers, a risk enhancing effect of involuntary/passive smoking prior to twenty years of age was observed (P < 0.05). No consistent associations were found with coffee, black tea or alcohol consumption. Among dietary factors, favoring food of a salty taste and drinking green tea five cups per day or more were positively associated with the risk. Drinking milk and eating fish everyday were inversely associated with the risk.