Therapeutic effects of restricted diet and exercise in obese patients with fatty liver

BACKGROUND/AIMS

The incidence of obese patients with fatty liver has recently increased in Japan as well as in the United States and Europe. Fatty liver may occasionally progress to liver cirrhosis. In this study, we have compared the effects of restricted diet and exercise versus no treatment in obese patients with fatty liver.

METHODS

Twenty-five obese patients with fatty liver were divided into treated and control groups. Fifteen obese patients followed a program of restricted diet (ideal weight x 25 Cal x kg(-1)) and exercise (walking or jogging) for a trial period of 3 months. No changes in diet or lifestyle were made by the other 10 patients during the same trial period. Blood biochemical tests and liver histology were compared in all patients before and after the trial.

RESULTS

In the treated group, weight, blood biochemical data such as aminotransferase, albumin, cholinesterase, total cholesterol and fasting blood glucose values, and steatosis were significantly decreased after the trial. In the control group, there were no significant differences in the clinical and histological findings before and after the trial.

CONCLUSIONS

These results indicate that restricted diet and exercise therapy, such as walking and jogging, are useful means of improving blood biochemical data and histological findings in liver tissues related to fatty liver.

Genetic evidence for involvement of type 1, type 2 and type 3 inositol 1,4,5-trisphosphate receptors in signal transduction through the B-cell antigen receptor

Stimulation of B-cell antigen receptor (BCR) induces a rapid increase in cytoplasmic free calcium due to its release from intracellular stores and influx from the extracellular environment. Inositol 1,4,5-trisphosphate receptors (IP3Rs) are ligand-gated channels that release intracellular calcium stores in response to the second messenger, inositol 1,4,5-trisphosphate. Most hematopoietic cells, including B cells, express at least two of the three different types of IP3R. We demonstrate here that B cells in which a single type of IP3R has been deleted still mobilize calcium in response to BCR stimulation, whereas this calcium mobilization is abrogated in B cells lacking all three types of IP3R. Calcium mobilization by a transfected G protein-coupled receptor (muscarinic M1 receptor) was also abolished in only triple-deficient cells. Capacitative Ca2+ entry, stimulated by thapsigargin, remains unaffected by loss of all three types of IP3R. These data establish that IP3Rs are essential and functionally redundant mediators for both BCR- and muscarinic receptor-induced calcium mobilization, but not for thapsigargin-induced Ca2+ influx. We further show that the BCR-induced apoptosis is significantly inhibited by loss of all three types of IP3R, suggesting an important role for Ca2+ in the process of apoptosis.

Increased expression of vascular endothelial growth factor is associated with tumor progression in hepatocellular carcinoma

Vascular endothelial growth factor is a potent direct-acting angiogenic factor. Early in hepatocarcinogenesis, hepatocellular carcinomas do not show hypervascularity; at later stages, they require abundant arterial blood flow. We investigated the role of vascular endothelial growth factor in hepatocellular carcinoma arterialization. We studied 51 patients with hepatocellular carcinoma. All patients had undergone hepatic arteriography. Vascular endothelial growth factor expression was investigated by immunohistochemistry (n = 51) and in situ hybridization (n = 13), and the changes in vascular endothelial growth factor expression were evaluated in relation to tumor differentiation and changes in tumor vascularity. The expression of vascular endothelial growth factor isoforms in hepatocellular carcinomas was also analyzed by reverse transcriptase-polymerase chain reaction (n = 10). Vascular endothelial growth factor expression was detected in hepatoma cells and hepatic stellate cells, and increased vascular endothelial growth factor expression was associated with tumor dedifferentiation. Vascular endothelial growth factor expression in hypervascular hepatocellular carcinomas was greater than in those not showing hypervascularity. The major vascular endothelial growth factor isoforms expressed in hepatocellular carcinoma were 121 and 165. These findings indicate that vascular endothelial growth factors 121 and 165 play a critical role in the process of angiogenesis in hepatocellular carcinomas.

CD45 modulates phosphorylation of both autophosphorylation and negative regulatory tyrosines of Lyn in B cells

CD45 is a tyrosine phosphatase that is required for normal B cell receptor (BCR)-mediated signaling. It has been shown that Src-family tyrosine kinases such as Lyn could be a potential substrate for CD45. In vitro studies indicate that activities of Src family tyrosine kinases are regulated by tyrosine phosphorylation; C-terminal phosphorylation is inhibitory, and autophosphorylation is stimulatory. We report here that both autophosphorylation and C-terminal negative regulatory tyrosines of Lyn were hyperphosphorylated in CD45-deficient DT40 B cells. In this mutant cell, BCR-induced protein-tyrosine phosphorylation and calcium mobilization were severely compromised, as seen in Lyn-deficient cells. Consistent with this observation, Lyn activation upon receptor ligation was profoundly decreased in CD45-deficient cells. Taken together, our results suggest that dephosphorylation of tyrosine residues at both autophosphorylation and negative regulatory sites is mediated by CD45 in vivo, and that dephosphorylation of C-terminal tyrosine is a prerequisite for participation of Lyn in BCR signaling.

Relationship between interleukin-6 and proliferation and differentiation in cholangiocarcinoma

AIMS

Interleukin-6 (IL-6) has been implicated as a mediator of growth control in several human neoplasms. The significance of IL-6 expression in human cholangiocarcinoma was examined in this study.

METHODS AND RESULTS

IL-6 expression was examined in 43 surgically resected cholangiocarcinomas and a cholangiocarcinoma cell line CCKS1, derived from abdominal metastasis of moderately differentiated adenocarcinoma, by immunohistochemical and in-situ hybridization techniques. In non-neoplastic bile ducts, IL-6 was constitutively but weakly expressed. In surgical cases of cholangiocarcinoma, IL-6 was frequently and strongly expressed in the cytoplasm of well-differentiated cholangiocarcinoma, while its expression was decreased, and less intense or absent in moderately and poorly differentiated areas, respectively. IL-6 mRNA was detected in the cytoplasm of carcinoma cells of two cases of cholangiocarcinomas positive for IL-6. IL-6 was detected in hepatic bile from two cholangiocarcinoma cases studied. The proliferation antigen Ki67 was found to be more frequently expressed in IL-6 negative carcinoma cells than in IL-6 positive carcinoma cells (P < 0.01). In cultured carcinoma cells line CCKS1, IL-6, IL-6 mRNA and IL-6 receptor alpha chain were detected in the cytoplasm of carcinoma cells, suggesting an autocrine effect of IL-6 on carcinoma cells.

CONCLUSION

IL-6 expression is inversely related to cell proliferation and positively related to differentiation in cholangiocarcinoma.

DNA Data Bank of Japan (DDBJ) for genome scale research in life science

The DNA Data Bank of Japan (DDBJ, http://www.ddbj.nig.ac.jp) has made an effort to collect as much data as possible mainly from Japanese researchers. The increase rates of the data we collected, annotated and released to the public in the past year are 43% for the number of entries and 52% for the number of bases. The increase rates are accelerated even after the human genome was sequenced, because sequencing technology has been remarkably advanced and simplified, and research in life science has been shifted from the gene scale to the genome scale. In addition, we have developed the Genome Information Broker (GIB, http://gib.genes.nig.ac.jp) that now includes more than 50 complete microbial genome and Arabidopsis genome data. We have also developed a database of the human genome, the Human Genomics Studio (HGS, http://studio.nig.ac.jp). HGS provides one with a set of sequences being as continuous as possible in any one of the 24 chromosomes. Both GIB and HGS have been updated incorporating newly available data and retrieval tools.

Spontaneous bubble domain formation in a layered ferromagnetic crystal

Magnetic domain structure on the surface of the layer-structured ferromagnet La1.4Sr1.6Mn2O7 was observed in the temperature range from 37 to 97 kelvin with a scanning Hall probe microscope. The sensitivity to temperature of the domain structure changes was large relative to that in conventional ferromagnets. The stable and spontaneous appearance of magnetic bubble domains without an external magnetic field was observed in the neighborhood of 70 kelvin. The phenomenon observed could provide a potential route toward magnetic bubble memory.

DNA Data Bank of Japan (DDBJ) in XML

The DNA Data Bank of Japan (DDBJ, http://www.ddbj.nig.ac.jp) has collected and released more entries and bases than last year. This is mainly due to large-scale submissions from Japanese sequencing teams on mouse, rice, chimpanzee, nematoda and other organisms. The contributions of DDBJ over the past year are 17.3% (entries) and 10.3% (bases) of the combined outputs of the International Nucleotide Sequence Databases (INSD). Our complete genome sequence database, Genome Information Broker (GIB), has been improved by incorporating XML. It is now possible to perform a more sophisticated database search against the new GIB than the ordinary BLAST or FASTA search.

Circulating intercellular adhesion molecule-1 (ICAM-1) antigen in sera of patients with idiopathic pulmonary fibrosis

Intercellular adhesion molecule-1 (ICAM-1), a member of immunoglobulin supergene family with a five-domain structure, is known to play an important role in inflammatory diseases. An ELISA was developed using two MoAbs against human ICAM-1 in order to detect the soluble shedding ICAM-1 antigen in sera. We measured levels of circulating ICAM-1 antigen in sera of patients with idiopathic pulmonary fibrosis (IPF), pulmonary sarcoidosis, hypersensitive pneumonitis, bacterial and mycoplasmal pneumonia, and inflammatory diseases of other organs. The results clearly demonstrated that IPF had significantly high levels of circulating ICAM-1 in sera as compared with other disorders or normal controls. Moreover, immunohistochemical analysis with MoAb against human ICAM-1 disclosed that in IPF, the expression of ICAM-1 was intensively enhanced on alveolar epithelial cells. These results suggest that ICAM-1 may contribute to the pathogenesis of IPF.

Effects of levosimendan on myocardial contractility and Ca2+ transients in aequorin-loaded right-ventricular papillary muscles and indo-1-loaded single ventricular cardiomyocytes of the rabbit

Effects of levosimendan on myocardial contractility and Ca2+ transients were assessed in the ventricular myocardium of the rabbit. Levosimendan at and above 0.1 microM had a concentration-dependent positive inotropic effect (PIE) on isolated papillary muscles that had been loaded with aqeuorin. The maximum inotropic response to levosimendan at 3 microM was approximately 20% of the maximum response to isoproterenol (ISOmax), whereas the maximum increase in the amplitude of Ca2+ transients was approximately 11% of ISOmax. For a given PIE, levosimendan increased the amplitude of Ca2+ transients much less than an elevation of [Ca2+]o. Levosimendan did not prolong the relaxation time. Similar results were obtained in single ventricular cardiomyocytes that had been loaded with indo-1. In the presence of the muscarinic receptor agonist carbachol, both the PIE and the increase in the Ca2+ transient induced by levosimendan were markedly attenuated. During wash-out of both carbachol and levosimendan, the contractile force increased conspicuously with little change in the amplitude of Ca2+ transients, an indication that the increase in myofibrillar sensitivity to Ca2+ ions elicited by levosimendan was susceptible to carbachol. Levosimendan at and above 0.03 microM shifted the concentration-response curve for isoproterenol to the left. Levosimendan had a positive chronotropic effect at 0.01 microM and higher in the isolated right atrium of the rabbit. These findings indicate that, in addition to the increase by levosimendan of the sensitivity of contractile proteins to Ca2+ ions, the accumulation of cyclic AMP due to the phosphodiesterase-inhibitory action of levosimendan might contribute to the PIE of this drug.

Basic fibroblast growth factor regulates proliferation and motility of human hepatoma cells by an autocrine mechanism

BACKGROUND/AIMS

Basic fibroblast growth factor has mitogenic and angiogenic properties. In this study, we aimed to evaluate the role of fibroblast growth factor in the development and progression of human hepatocellular carcinoma.

METHODS

The expression of basic fibroblast growth factor, fibroblast growth factor receptor-1, and a receptor isoform was investigated by in situ hybridization, immunohistochemistry, reverse transcription-polymerase chain reaction, Western blot analysis and confocal laser-scanning microscopy. The influence of exogenous basic fibroblast growth factor on DNA synthesis and motility of human hepatoma cells were also evaluated.

RESULTS

Basic fibroblast growth factor and fibroblast growth factor receptor-1 messenger RNAs were present mainly in tumor cells and less so in hepatocytes from noncancerous liver tissue. Immunoreactive products of basic fibroblast growth factor and fibroblast growth factor receptor-1 were observed in tumor cells. The isoform IIIc was expressed in hepatocellular carcinoma tissue and hepatoma cell lines. Exogenous basic fibroblast growth factor stimulated DNA synthesis and motility of hepatoma cells. The effect was more marked in poorly-differentiated hepatoma cells than in well-differentiated hepatoma cells. Fibroblast growth factor-1 expression on hepatoma cells was also more marked in poorly-differentiated hepatoma cells than in well-differentiated hepatoma cells. The stimulated motility on basic fibroblast growth factor was suppressed by an anti-fibroblast growth factor receptor-1 antibody.

CONCLUSIONS

Basic fibroblast growth factor may play an important role in the development and progression of hepatocellular carcinoma via an autocrine mechanism involving fibroblast growth factor and its receptor.

Crystal structure of carboxylase reaction-oriented ribulose 1, 5-bisphosphate carboxylase/oxygenase from a thermophilic red alga, Galdieria partita

Ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco, EC 4.1.1. 39) obtained from a thermophilic red alga Galdieria partita has the highest specificity factor of 238 among the Rubiscos hitherto reported. Crystal structure of activated Rubisco from G. partita complexed with the reaction intermediate analogue, 2-carboxyarabinitol 1,5-bisphosphate (2-CABP) has been determined at 2.4-A resolution. Compared with other Rubiscos, different amino residues bring the structural differences in active site, which are marked around the binding sites of P-2 phosphate of 2-CABP. Especially, side chains of His-327 and Arg-295 show the significant differences from those of spinach Rubisco. Moreover, the side chains of Asn-123 and His-294 which are reported to bind the substrate, ribulose 1,5-bisphosphate, form hydrogen bonds characteristic of Galdieria Rubisco. Small subunits of Galdieria Rubisco have more than 30 extra amino acid residues on the C terminus, which make up a hairpin-loop structure to form many interactions with the neighboring small subunits. When the structures of Galdieria and spinach Rubiscos are superimposed, the hairpin region of the neighboring small subunit in Galdieria enzyme and apical portion of insertion residues 52-63 characteristic of small subunits in higher plant enzymes are almost overlapped to each other.

Involvement of cAMP/EPAC/TRPM2 activation in glucose- and incretin-induced insulin secretion

In pancreatic β-cells, closure of the ATP-sensitive K(+) (K(ATP)) channel is an initial process triggering glucose-stimulated insulin secretion. In addition, constitutive opening of background nonselective cation channels (NSCCs) is essentially required to effectively evoke depolarization as a consequence of K(ATP) channel closure. Thus, it is hypothesized that further opening of NSCC facilitates membrane excitability. We identified a class of NSCC that was activated by exendin (ex)-4, GLP-1, and its analog liraglutide at picomolar levels. This NSCC was also activated by increasing the glucose concentration. NSCC activation by glucose and GLP-1 was a consequence of the activated cAMP/EPAC-mediated pathway and was attenuated in TRPM2-deficient mice. The NSCC was not activated by protein kinase A (PKA) activators and was activated by ex-4 in the presence of PKA inhibitors. These results suggest that glucose- and incretin-activated NSCC (TRPM2) works in concert with closure of the KATP channel to effectively induce membrane depolarization to initiate insulin secretion. The current study reveals a new mechanism for regulating electrical excitability in β-cells and for mediating the action of glucose and incretin to evoke insulin secretion, thereby providing an innovative target for the treatment of type 2 diabetes.

Role of Na+/Ca2+ exchange in endothelin-1-induced increases in Ca2+ transient and contractility in rabbit ventricular myocytes: pharmacological analysis with KB-R7943

1. The effects of endothelin-1 (ET-1) on intracellular Ca2+ ion level and cell contraction were simultaneously investigated in rabbit ventricular cardiac myocytes loaded with indo-1/A1. The role of Na+/Ca2+ exchange in ET-1-induced positive inotropic effect (PIE) was examined by using KB-R7943 (2-[2-[4-(4-nitrobenzyloxy)phenyl]ethyl]isothiourea methanesulphonate), a selective inhibitor of reverse mode Na+/Ca2+ exchange. 2. ET-1 at 0.3 pM - 1 nM increased cell contraction and Ca2+ transient (CaT) with EC50 values of 2.9 pM and 1.2 pM, respectively, and the increase in amplitude of CaT was much smaller relative to the PIE: ET-1 at 1 nM increased peak cell shortening by 237%, while it increased peak CaT by 167%. For a given level of PIE, ET-1-induced increase in CaT was much smaller than that induced by elevation of [Ca2+]o and by isoprenaline. Therefore, ET-1 shifted the relationship between peak CaT and cell shortening to the left relative to the relationship for increase in [Ca2+]o, an indication that ET-1 increased myofibrillar Ca2+ sensitivity. 3. KB-R7943 at 0.1 microM and higher inhibited contraction and CaT induced by 0.1 nM ET-1 and at 0.3 microM it abolished the increase in CaT while inhibiting the PIE by 48.1%. Over concentration range of 0.1-0.3 microM, KB-R7943 neither inhibited baseline contraction and CaT nor the isoprenaline-induced response, although at 1 microM and higher it had a significant inhibitory action on these responses. 4. These results indicate that in rabbit ventricular myocytes both increases in CaT and myofibrillar Ca2+ sensitivity contribute to the ET-induced PIE, and the activation of reverse mode Na+/Ca2+ exchange may play a crucial role in increase in CaT induced by ET-1 in rabbit ventricular cardiac myocytes.

Crystal structure determinations of oxidized and reduced plastocyanin from the cyanobacterium Synechococcus sp. PCC 7942

The crystal structures of oxidized and reduced plastocyanins from Synechococcus sp. PCC 7942 have been determined at 1.9 and 1.8 A resolution, respectively, at pH 5.0. The protein consists of only 91 amino acid residues, the smallest number known for a plastocyanin, and apparently lacks the mostly conserved acidic patch that is believed to be important for recognition with electron-transfer partners. The protein has two acidic residues, Glu42 and Glu85, around Tyr83, which is thought to be a possible conduit for electrons, but these are neutralized by Arg88 and Lys58. Residue Arg88 interacts with Tyr83 through a pi-pi interaction in which the guanidinium group of the former completely overlaps the aromatic ring of the tyrosine. Reduction of the protein at pH 5.0 causes a lengthening of one Cu-N(His) bond by 0.36 A, despite the small rms deviation of 0.08 A calculated for the backbone atoms. Moreover, significant conformational changes of Arg88 and Lys58, along with the movement of a water molecule adjacent to the OH group of Tyr83, were observed on reduction; the guanidinium group of Arg88 rotates by more than 11 degrees, and the water molecule moves by 0.42 A. The changes around the copper site and the alterations around Tyr83 may be linked to the reduction of the copper.

DDBJ in the stream of various biological data

In the past year we at DDBJ (http://www.ddbj.nig. ac.jp) have made a steady increase in the number of data submissions with a 50.6% increment in the number of bases or 46.5% increment in the number of entries. Among them the genome data of man, ascidian and rice hold the top three. Our activity has extended to providing a tool that enables sequence retrieval using regular expressions, and to launching our SOAP server and web services to facilitate the acquisition of proper data and tools from a huge number of biological data resources on websites worldwide. We have also opened our public gene expression database, CIBEX.

DNA data bank of Japan (DDBJ) in collaboration with mass sequencing teams

We at DDBJ (http://www.ddbj.nig.ac.jp) process and publicise the massive amounts of data submitted mainly by Japanese genome projects and sequencing teams. It is emphasised that the collaboration between data producing teams and the data bank is crucial in carrying out these processes smoothly. The amount of data submitted in 1999 is so large that it alone exceeds the total amount submitted in the preceding 10 years. To cope with this situation, we have developed tools not only for processing such massive amounts of data but also for efficiently retrieving data on demand.

Leuprorelin acetate granulomas: case reports and review of the literature

Leuprorelin acetate, an agonist of gonadotropin-releasing hormone (GnRH), is indicated in the treatment of prostate cancer. Recently, depot formulations of leuprorelin acetate have been widely used. We report three patients who showed a granulomatous reaction after treatment using a leuprorelin acetate 3-month depot formulation. These patients presented with 5-6-cm subcutaneous nodules at injection sites, which developed after the depot type was changed from a 1-month to a 3-month formulation. Skin biopsy showed epithelioid cells and foreign body giant cells containing round, translucent microspheres which formed sarcoidal granulomas. Changing to other GnRH agonists resulted in no further problems. We have reviewed the previous reports of leuprorelin acetate-induced granuloma formation. The formation of such granulomas may be related to the polymers that allow slow release after injection, or leuprorelin acetate itself may be responsible. The depot injection methods using leuprorelin also seem to have a causal effect in granuloma formation. Dermatologists need to know that depot leuprorelin acetate may cause a granulomatous reaction which produces a subcutaneous nodule that might be misdiagnosed as a malignant tumour.

Hepatic stellate cells and intralobular innervation in human liver cirrhosis

In normal and cirrhotic human liver tissues, we examined immunolocalization of alpha-smooth muscle actin (alpha-SMA), endothelin-1 receptor (ET-1R), and S-100 protein, with special emphasis on the intralobular spaces, using immunohistochemical methods. The ratio of the number of hepatic stellate cells (HSCs) with closely apposing nerve endings to the total number of HSCs in normal livers was compared with that in cirrhotic livers by electron microscopy. Immunolocalization of alpha-SMA and ET-1R was obviously recognized along the sinusoidal walls in cirrhotic liver and was significantly increased in cirrhotic liver compared with that in normal liver. Immunoreactive products for these substances were mainly localized in HSCs. However, immunolocalization of S-100 protein in intralobular spaces was markedly decreased in cirrhotic liver compared with that in normal liver. Nerve fibers were ultrastructurally hardly visible in intralobular spaces of cirrhotic livers. The ratio of the number of HSCs with closely apposing nerve endings to the total number of HSCs was significantly reduced in cirrhotic liver compared with that in normal liver. These results indicate that in liver cirrhosis, alpha-SMA-positive HSCs may play an important role in hepatic sinusoidal microcirculation through vasoactive agents such as ET-1 rather than through intralobular innervation.

Pressure-flow relations in dog arteries

The propagation of the arterial pressure and flow pulses through the vascular beds is characterized by marked changes in shape and magnitude. In order to understand better the mechanisms which account for these changes, instantaneous pressures and flows were measured simultaneously at various sites in the arterial tree of 12 anesthetized dogs, using Statham strain gauges and electromagnetic flowmeters. The data were processed by on-line Fourier analysis and the frequency spectra of pressure, flow and vascular impedance at these sites were evaluated. In these dogs about 10% of the cardiac output was distributed to the head, 14% to the kidney, 35% to the gastrointestinal tract, 14% to the pelvic organs and 6% to the legs. The input impedances of the various beds were frequency dependent, the frequency-dependent components varying between 2 and 45% of the corresponding D-C impedances (peripheral vascular resistance). The viscous losses associated with pulsatile flow were larger than those for corresponding steady flows. The excess losses varied between 9 and 30% of the mean flow losses. The marked decrease in cross section down the aorta lead to considerable acceleration of the mean blood velocity and corresponding pressure losses despite the drainage through aortic branches. Comparisons of measured flows with those predicted from Womersley's theory showed satisfactory agreement for short vascular segments. However the theory underestimates the losses occurring in the nonuniform arterial tree. On the basis of anatomic measurements, the space dependence of resistance, inertance and vascular distensibility was evaluated.