Quantitative evaluation of the gastrointestinal absorption of protein into the blood and lymph circulation

In order to investigate the fate of orally administered proteins, the absorption of ovalbumin (OVA) from the gastrointestinal tract into both the blood and lymph circulation was quantitatively evaluated. After oral administration, a significant amount of intact OVA was detected in both the plasma and the lymph fluid by means of a two-site enzyme immunoassay. The extent of absorption into the plasma, calculated from the area under the plasma concentration versus time curve of OVA after oral and intravenous administration, was only 0.007-0.008% of the dose. This value is extremely low compared to that after nasal administration, showing the stronger barrier function of the gastrointestinal tract against the invasion of macromolecular proteins into the body. The extent of absorption into the lymph was dose-dependent (0.0007-0.002% of dose), and a higher dose leads to a higher fraction of OVA absorbed into the lymph. Moreover, it was demonstrated that not only the small intestine but also the stomach can absorb OVA. OVA absorbed from the stomach was transferred almost exclusively to the blood circulation, which suggests different mechanisms and/or routes of absorption between the stomach and the small intestine. In order to improve the low oral absorption, OVA was incorporated in liposomes and administered orally. Although the effect of liposomes was not significant, it increased OVA absorption into both the plasma and lymph by about 2 to 3-fold. It was considered that the liposomes suppressed the enzymatic degradation of OVA and released it slowly in the gastrointestinal tract.

Exon 10 skipping caused by intron 10 splice donor site mutation in cholesteryl ester transfer protein gene results in abnormal downstream splice site selection

Cholesteryl ester transfer protein (CETP) deficiency is the most common cause of hyperalphalipoproteinemia in Japan. However, the genetic basis of this disorder has not been fully characterized. We have studied a 49-year-old Japanese male presenting with total cholesterol, HDL-cholesterol, and apolipoprotein A-I levels of 300, 236, and 233 mg/dl, respectively, and total absence of CETP activity and mass in plasma. Sequence analysis of the patient's CETP gene revealed that the splice donor consensus GT was substituted by GG in intron 10 (intron 10 splice defect) and by AT in intron 14 (intron 14 splice defect). Restriction digestion of PCR-amplified DNA using NdeI and MaeIII established that the patient was a compound heterozygote for both gene defects. Sequencing of cDNA amplified by RT-PCR from the patient's monocyte-derived macrophage RNA demonstrated abnormal splicing with deletion of exon 10 as well as alternative splicing at a native AG site located 31 nucleotides 5' of the normal splice acceptor in intron 13. Thus, the intron 10 splice defect results in exon 10 skipping and the insertion of a 31 bp fragment between exon 13 and exon 14, which contains an in frame stop codon. The presence of abnormally spliced mRNA was further confirmed by amplification of patient cDNA using CETP specific primers. Abnormal splicing of exon 14 as a result of the intron 14 splice defect was not detected, indicating potential unstable CETP mRNA derived from that mutation. These findings demonstrate that a novel splice site mutation in intron 10 of the CETP gene results in the skipping of exon 10, as well as disruption of downstream splicing at intron 13 identifying a novel mechanism leading to CETP deficiency.

A novel nonsense mutation (G181X) in the human cholesteryl ester transfer protein gene in Japanese hyperalphalipoproteinemic subjects

Cholesteryl ester transfer protein (CETP) plays an important role in regulating the concentration and composition of high density lipoprotein (HDL) and low density lipoprotein (LDL). Although several genetic abnormalities causing CETP deficiency have been identified in the Japanese subjects with a marked hyperalphalipoproteinemia (HALP), there are many CETP-deficient subjects for whom the genetic abnormalities have not been clarified. In the present study, we analyzed the molecular basis of an HALP subject without CETP activity and mass, and found a novel mutation in the CETP gene. This novel mutation (G181X) was a G-to-T substitution at codon 181 of exon 6 which replaced a codon for glycine (GGA) with a premature stop codon (TGA). The G181X mutation created a new cutting site by restriction enzyme MaeIII. To estimate the frequency of G181X, we investigated unrelated 294 HALP (HDL-cholesterol > or = 2.59 mmol/L = 100 mg/dl) subjects by restriction fragment length polymorphism (RFLP) analysis with Mae III. One (0.34%) HALP subject was homozygous and four (1.36%) were heterozygous for this mutation. The allelic frequency of a G-to-T substitution at codon 181 of exon 6 was 0.0102 in HALP subjects. From the lipid analysis of the proband and the homozygote, it was clarified that the G181X mutation had dominant effects on HDL and LDL metabolism, similar to a G-to-A substitution at the 5' splice donor site of the intron 14 (1451 + 1G-->A). In conclusion, the G181X mutation is one of causes of HALP in the Japanese HALP subjects, having dominant effects on lipid metabolism.

Osteogenic action of parathyroid hormone-related peptide (1-141) in rat ROS cells

To examine the autocrine/paracrine effect of parathyroid hormone-related peptide (PTHrP) on osteoblast function, the entire coding region of rat PTHrP (1-141) cDNA inserted into the expression vector was stably transfected into the rat clonal strain of the osteoblast-like cell, ROS 17/2.8, and established stable transfectants. Using the PTHrP-overexpressing ROS cells (ROS/PLP/6), we analyzed in vitro cell characterization and in vivo osteogenic properties. As expected, overexpression of endogenous PTHrP in vitro induced PTH/PTHrP receptor down-regulation confirmed by Northern blots, receptor binding assays, and functional analysis. The established transfectants indicated a decreased growth rate compared with the original non-transfected ROS 17/2.8. Although cAMP production induced by exogenous PTH was suppressed in ROS/PLP/6, the stimulatory effects of forskolin and chorela toxin showed no significant difference between the original ROS 17/2.8 and transfected cells, but the in vivo osteogenic properties were histologically potentiated in transfectants with increased bone matrix and acceleration of mineralization within tumors. The levels of osteocalcin and osteopontin mRNAs were also increased in transfectants. The down-regulated in vitro PTH/PTHrP receptor mRNA was restored in in vivo tumor tissues. Our study provides clear evidence that the in vivo osteogenic function in ROS cells is potentiated by PTHrP, through an autocrine/paracrine mode of action.

Adenosine 3',5'-cyclic monophosphate mimics the inhibitory effect of high glucose on MAP kinase phosphorylation in rat mesangial cells

Alteration in mesangial cell function induced by high glucose levels is implicated in the development of diabetic nephropathy. The aim of this study was to investigate the mechanism by which high glucose attenuates mesangial cell proliferation. Thymidine incorporation in cultured mesangial cells decreased in the presence of high glucose concentrations in a dose dependent manner, with the maximum decrease of 25% occurring at a glucose concentration of 55.5 mM. Phosphorylation of mitogen-activated protein (MAP) kinase was abolished when the cells were treated with 55.5 mM glucose compared with 11.1 mM glucose. The concentration of intracellular cAMP doubled in the presence of 55.5 mM glucose. The addition of 8Br-cAMP (1.0 mM) to the culture media containing 11.1 mM glucose decreased thymidine incorporation by 34%, similar to the effect of high glucose. In order to clarify the contribution of protein kinase A (PKA) to the MAP kinase cascade, we used PKA inhibitor (H-8). The addition of H-8(10 microM) recovered MAP kinase phosphorylation in the presence of 55.5 mM glucose. Our data indicated that the inhibition of this mitogenic pathway mediated by activation of PKA, which is probably induced by high glucose levels, may play an important role in the perturbation of mesangial cells.

Molecular cloning of rat phosphatidylinositol synthase cDNA by functional complementation of the yeast Saccharomyces cerevisiae pis mutation

Phosphatidylinositol synthase (CDP-1,2-diacyl-sn-glycerol: 3-phosphatidyltransferase, EC 2.7.8.11) catalyzes the formation of phosphatidylinositol and CMP from CDP-diacylglycerol and myo-inositol. We have cloned a phosphatidylinositol synthase cDNA from rat brain by functional complementation of the yeast pis mutation, which is defective in phosphatidylinositol synthase. The deduced protein comprised 213 amino acids with a calculated molecular mass of 23,613 Da. The predicted protein sequence is highly homologous to the previously determined yeast phosphatidylinositol synthase sequence. The cDNA hybridized to a 1.7-kb mRNA that was abundantly expressed in rat brain and kidney.

[Mutation induction by heavy ion beams and X-rays: analysis with cultured cell line]

This study was performed to determine the biological effects of heavy ion beams on cultured cells. V79 cells were irradiated with carbon or neon beams or X-rays, and cell survivals was calculated by the colony assay method. The Do values for 150 kVp X-rays, 20 keV/micron and 80 keV/micron carbon beams, and 80 keV/micron neon beams were 2.2Gy, 1.8Gy, 1.0Gy and 1.4Gy, respectively. After 7-10 day expression periods, the mutation frequencies at the hypoxanthine-guanine phosphribosyl transferase (hprt) locus were analyzed from the numbers of colonies formed in media supplemented with 6-thioguanine. An extremely higher frequency of mutation was observed with heavy ion beams compared with X-rays. Both cell killing effect and the mutation induction were enhanced when the LET of carbon beams was increased from 20 to 80 keV/micron. These results mean that carbon beams had a stronger cell-killing effect than X-rays, but also carried a high risk of mutation induction. On the other hand, neon beams yielded cell survival curves similar to those of carbon beams, but they had a smaller mutation induction effect than carbon beams. The effect of fractionated irradiation (3 hr interval) on cell survival and mutation frequency were also examined. When cells were irradiated with X-rays, cell survival was increased by fractionation, but the mutation frequency was not modified. Irradiating cells with fractionated carbon beams, survival curves were not affected, but mutation frequency was reduced.

Parathyroid hormone-related protein (PTHrP) action in rat articular chondrocytes: comparison of PTH(1-34), PTHrP(1-34), PTHrP(1-141), PTHrP(100-114) and antisense oligonucleotides against PTHrP

Parathyroid hormone-related protein (PTHrP) is thought to be an important autocrine/paracrine factor for chondrocyte metabolism since mice lacking the PTHrP gene exhibit abnormal cartilage development. To determine the biological role of PTHrP in chondrocytes, we first compared the agonist potency of human (h) PTHrP(1-34) with hPTH(1-34) in cultured rat articular chondrocytes. Neither hPTHrP(1-34) nor hPTH(1-34) altered basal DNA synthesis, but attenuated the stimulatory effect of transforming growth factor beta (TGF-beta). Both agents suppressed the expression of alpha(1) type II collagen mRNA in a dose-response fashion with the same potency. In addition, the action of exogenously added hPTHrP(1-34) and hPTH(1-34) on intracellular cAMP and [Ca2+]i levels was similar. We next compared the effect of PTHrP within its entire amino acid sequence (1-141). With regard to thymidine incorporation, alpha(1) type II collagen gene expression and accumulation of cAMP and [Ca2+]i level, there was no significant difference between hPTHrP(1-34) and hPTHrP(1-141). PTHrP C-terminal (100-114) did not show any function. To further investigate PTHrP function, intracellular PTHrP translation was inhibited by a transgene of antisense oligonucleotides against PTHrP. Antisense oligonucleotides decreased PTHrP mRNA translation, specifically inhibited DNA synthesis in control as well as TGF-beta-treated chondrocytes and enhanced alpha(1) type II collagen mRNA expression in TGF-beta-treated chondrocytes. These results suggest that there is no significant difference between exogenously added hPTH(1-34), hPTHrP(1-34) and PTHrP(1-141) with regard to the biological action of these agents, including cell growth, differentiation and second messenger pathway. However, the result of DNA synthesis in the antisense PTHrP-inhibition study suggests that intracellular PTHrP may have an as yet unknown biological role, in addition to a classical PTH/PTHrP receptor-mediated function in the rat articular chondrocyte.

Expression of parathyroid hormone (PTH)-related peptide (PTHrP) and PTH/PTHrP receptor in giant cell tumour of tendon sheath

The giant cell tumour of tendon sheath (GCTTS) is mainly composed of mononucleated stromal cells (SC) and multinucleated giant cells (GC), so-called osteoclast-like GC. It is thought that GC are derived from SC, but their precise relationship is not fully understood. Parathyroid hormone (PTH)-related peptide (PTHrP) is now considered to be a cytokine for cell differentiation, which may stimulate osteoclast-like cell formation in haematopoietic cells. Five cases of GCTTS were evaluated immunohistochemically, using a variety of antibodies against PTHrP, PTH/PTHrP receptor, KP-1 as a histiocytic phenotypic antigen, fibronectin as a fibroblastic phenotypic antigen, and proliferating cell nuclear antigen (PCNA). In situ hybridization and immunohistochemistry revealed that in all cases both SC and GC expressed PTHrP. PTH/PTHrP receptor was observed only in histiocytic SC and GC, but not in fibroblastic SC. Almost all GC showed histiocytic features. PCNA immunoreactivity was detected only in the nuclei of SC, and not in GC. Moreover, SC with PTH/PTHrP receptor immunoreactivity were negative for PCNA. These results suggest that GC are derived from histiocytic SC expressing PTH/PTHrP receptor and losing proliferative activity in the process of transition from mononuclear to multinucleated. PTHrP produced by SC and GC may be involved in the formation of osteoclast-like cells in GCTTS by acting in an autocrine/paracrine fashion.

Characterization of cultured rat embryonic palatal mesenchymal cells

To investigate developmental palatogenesis, the establishment of palatal cell culture in vitro is preferable to eliminate several complicated biases present in the in vivo environment. We established a primary culture of rat embryonic palatal mesenchymal cells using a special technique to dissect embryonic palatal shelves, and characterized these embryonic cells by immunohistochemical analysis against histiocytic markers. Following preparation of the maxilla of 15.5-day-old rat fetuses, a midline incision of the maxilla was established while the occiput was fixed with microforceps. This procedure allowed eversion of the maxillary process and easy dissection of the palatal shelf. The technique allowed preparation of a large number of palatal shelves with no appendages using a small number of fetuses. Cells cultured with DMEM/F-12 and 10% FBS showed multipotential nature (i.e., not only mere mesenchymal character but also neural, endothelioid, and/or myoblastoid origin were identified by immunostaining with anti-epithelium membrane antigen, keratin, vimentin, S-100 protein, factor VIII, desmin, and lysozyme antibodies, respectively). Our results demonstrated that, during several cell passages, the cultured cell gained myoblastoid characteristics in addition to a neural nature. Further in vitro studies using cultured embryonic palatal mesenchymal cells will assist in characterization of proliferation and differentiation of cells forming the palate.

[CA19-9 producing mixed gonadal germ-cell tumor in undescended testis located in abdomen. A case report]

A rare case of CA19-9 producing tumor in undescended testis was presented. A forty-three year old man visited to our hospital with a chief complaint of left flank pain. Serum tumor markers (AFP, beta-HCG, and CA19-9) were elevated. Abdominal CT scan demonstrated large solid mass with multilocular cysts were capsulated. The tumor resection was performed after 3 courses of CEB (Carboplatin, Etoposide, and Bieomycin) chemotherapy. Macroscopically, the tumor was consisted of necrotic mass and multilocular cysts. The tumor size was 25 x 8 x 5 cm and weight was 1000 g. Microscopically, the large part of tumor was necrotic due to chemotherapy, and the teratoma component which was consist of neural, muscular, and digestive tissue was seen in some area. In conclusion, this is a rare case of mixed germ-cell tumor in undescended testis located in abdomen.

Specificity of glossopharyngeal nerve responses to astringent compounds in Xenopus

Astringent compounds were applied to oral epithelium of the clawed toad, Xenopus laevis, and rapidly rising and highly sensitive responses could be recorded from the whole glossopharyngeal nerve, but not at all from the trigeminal nerve. The response to 10 mM tannic acid decreased progressively with repetitive application. These responses to tannic acid, however, recovered completely by treating with chemicals capable of forming strong hydrogen and hydrophobic bonds. These chemical bondings are generally recognized as a model for polyphenol (tannin)-protein interactions based on physico-chemical measurements in vitro. The high affinities of these chemicals for tannic acid may be effective in releasing both bonds in the interaction of tannic acid with the receptor molecules. Our results provide in vivo evidence for this model.

Effect of Habu (Trimeresurus flavoviridis) antivenom on changes of hemostatic parameters following administration of crude venom from T. flavoviridis in rabbits

We carried out experiments to examine the efficacy of Habu antivenom in relation to variations of hemostatic parameters induced by the administration of crude venom to rabbits. For neutralization of the crude venom by Habu antivenom, the correlation between the concentrations of Habu antivenom (Y) and crude venom (X) was expressed by the equation: Y = -0.473 + 0.539X. We examined the variations in hemostatic parameters in the state which crude venom was neutralized by Habu antivenom following the administration of crude venom (1 mg/kg) from Trimeresurus flavoviridis. Although the hemostatic parameters [level of fibrinogen, antithrombin III (AT-III) activity and alpha 2-plasmin inhibitor (alpha 2-PI) activity] underwent decreases after the administration of crude venom, they revealed fluctuations within the normal range after the Habu antivenom administration. The AT-III activity, however, decreased gradually until 90 min after the antivenom administration. These results suggested that Habu antivenom was effective in improving the abnormal coagulant activity induced by crude venom. However, the neutralization effect towards the coagulant activity of crude venom by the Habu antivenom did not continue for a long time and did not lead to recovery of the AT-III activity. Since excessive doses of antivenom can induce serious medical problems, we expect that simultaneous use of antivenom and AT-III preparation, instead of excessive and single use of Habu antivenom could provide a useful therapy for snake bites from the present study.

[Biological effect of carbon beams on cultured human cells]

This study was performed to determine the biological effect of carbon beams on 13 human tumor cells, in comparison with 200 KVp X-rays. Carbon beams were generated by the Riken Ring Cyclotron. The RBE (relative biological effectiveness) values were distributed from 1.46 to 2.20 for LET of 20 ke V/micron, and 2.29-3.54 for 80 keV/micron. The RBEs were increased in all cell lines as the LET of carbon beams was increased from 20 to 80 keV/micron. There was no significant difference in radiosensitivity between cells from adenocarcinoma and those from squamous cell carcinoma. The relationship between the radiosensitivity of cells to X-rays and RBE was analyzed, but no significant correlation was suggested. Several survival curves of 20-40 keV/micron carbon beam irradiation showed the initial shoulders and the recovery ratios between two split doses were determined. Recovery was observed for LET of 20 keV/micron but not for that of 40 keV/micron. Furthermore, recovery ratios were 1.0-1.8, smaller than those for X-rays (1.5-2.4).

Expression of hepatocyte growth factor, transforming growth factor alpha, and transforming growth factor beta 1 messenger RNA in various human liver diseases and correlation with hepatocyte proliferation

Hepatocyte growth factor (HGF) and transforming growth factor alpha (TGF-alpha) stimulate liver regeneration, whereas transforming growth factor beta 1 (TGF-beta 1) inhibits it in rats. However their significance in human liver diseases, especially in severe acute liver injury, remains unclear. We studied HGF, TGF-alpha, and TGF-beta 1 messenger RNA (mRNA) expression in the livers of patients with live diseases using a competitive reverse transcriptase polymerase chain reaction. As little as a twofold difference in mRNA expression could be detected from minute liver biopsy samples. We then examined cell proliferation using proliferating cell nuclear antigen (PCNA) staining. HGF mRNA levels were significantly higher (approximately threefold) in acute hepatitis (AH) than in exacerbation of chronic liver disease (EX) (P < .05). TGF-alpha mRNA levels were significantly greater in AH (approximately twofold) than EX (P < .05), and the levels were significantly higher (approximately threefold) in chronic hepatitis (CH) than in EX (P < .05). The TGF-beta 1 mRNA levels in all the groups were not significantly different. In acute liver injury (AH and EX), there was a significant correlation between HGF mRNA expression and the PCNA labeling index (LI) in the liver (r = .87, P < .005). TGF-alpha mRNA expression also correlated with the PCNA LI (r = .92,P < .0001). There was no significant correlation between the serum HGF and the PCNA LI in the liver. In conclusion, HGF and TGF-alpha produced in the liver stimulate hepatocyte proliferation in response to acute liver injury in humans.

Fish glucocorticoid receptor with splicing variants in the DNA binding domain

Here we describe the isolation of a rainbow trout cDNA containing an entire GR coding region. Although the encoded protein is highly homologous to other GRs, especially in its DNA binding domain, it contains a nine amino acid insertion between the two zinc fingers. This novel form is found in all rainbow trout tissues examined; however, the testis also contains a splice variant lacking this insert, making it completely continuous to other GRs. In transient transfection assays of cultured cells, the two rainbow trout GR variants activated transcription from the glucocorticoid-responsive mouse mammary tumor virus promoter to comparable levels.

Enhanced expression of PAI-1 in visceral fat: possible contributor to vascular disease in obesity

The presence of obesity increases the risk of thrombotic vascular diseases. The role of fat accumulation and its effect on plasminogen activator inhibitor-1 (PAI-1) levels was investigated in humans and animals. Plasma PAI-1 levels were closely correlated with visceral fat area but not with subcutaneous fat area in human subjects. PAI-1 mRNA was detected in both types of fat tissue in obese rats but increased only in visceral fat during the development of obesity. These data suggest that an enhanced expression of the PAI-1 gene in visceral fat may increase plasma levels and may have a role in the development of vascular disease in visceral obesity.

Localisation of apoptosis and expression of apoptosis related proteins in the synovium of patients with rheumatoid arthritis

OBJECTIVES

To investigate whether apoptosis occurs in the synovium of rheumatoid arthritis (RA), and the intermediate molecules operating in this process.

METHODS

DNA fragmentation was detected by in situ nick end labelling (ISNEL) in the synovium of patients with RA (n = 11) and control patients with femoral neck fracture (n = 5). The expression of proteins p53, p21WAFI/CIPI, c-myc, proliferating cell nuclear antigen (PCNA), and Bcl-2 was also examined by immunohistochemistry.

RESULTS

ISNEL positive synovial cells with apoptosis specific morphology were detected in extremely limited areas in only two RA synovial tissue specimens. Proteins p53, p21WAFI/CIPI, and c-myc, known inducers of apoptosis or cell cycle arrest or both, were expressed in the sublining cells independent of ISNEL positive cells. PCNA, a marker for cell proliferation, was observed in the synovial lining cells. Bcl-2, an inhibitor of apoptosis, was expressed mainly in infiltrated lymphocytes and in parts of the sublining layer cells of RA; it also did not correspond with ISNEL staining.

CONCLUSIONS

Our findings indicate that RA synovial cells undergo apoptosis in addition to cell proliferation, but the frequency of apoptosis was very low. We suspect that the apoptotic process in the RA synovium may be suppressed by over-expression of Bcl-2. Although expressed proteins p53, p21WAFI/CIPI, and c-myc were present in the RA synovium, these protooncogenes are probably not implicated in the apoptotic process.

Long exposure to high glucose concentration impairs the responsive expression of gamma-glutamylcysteine synthetase by interleukin-1beta and tumor necrosis factor-alpha in mouse endothelial cells

To elucidate the pathological metabolism of glutathione synthesis in diabetic endothelial cells, we studied the expression of gamma-glutamylcysteine synthetase (gamma-GCS) using a mouse vascular endothelial cell line. Exposing normoglycemic endothelial cells to tumor necrosis factor-alpha (TNF-alpha) or interleukin-1beta (IL-1beta) increased the activity and the mRNA expression of gamma-GCS. The addition of inhibitors for nuclear factor kappaB (NF-kappaB) to the cells caused a loss of the gamma-GCS mRNA expression in response to TNF-alpha. A shift of the concentration of glucose in the medium from 5.5 to 28 mM glucose and a following incubation for 7 days decreased the expression of gamma-GCS mRNA. These cells showed no apparent responses of gamma-GCS mRNA or the activity of NF-kappaB to TNF-alpha or IL-beta. Increase in the GSH concentration of the cells treated with 28 mM glucose restored the expression of gamma-GCS mRNA and its response to TNF-alpha or IL-beta, suggesting that redox regulation is involved in the expression of gamma-GCS. In summary, the expression of gamma-GCS is regulated by TNF-alpha or IL-1beta in endothelial cells mediated by NF-kappaB stimulation, and impairment of the regulation of gamma-GCS in hyperglycemic cells may be a cause of medical complications that develop in diabetes mellitus.