Isolation and characterization of the glyceraldehyde-3-phosphate dehydrogenase gene of Lentinus edodes

The glyceraldehyde-3-phosphate dehydrogenase (GPD) gene of Lentinus edodes was isolated from a genomic DNA library and cDNA corresponding to this gene was isolated from a mycelium cDNA library. The L. edodes GPD gene was found to encode a 337-aa protein. By comparison of the cDNA and genomic DNA sequences, the presence of eight introns in the GPD gene was confirmed. The putative amino acid sequence of the L. edodes GPD gene product showed high similarity to those of other basidiomycetes. The results of Southern blot analyses suggested that only one copy of the GPD gene is present in the genome of L. edodes. The promoter region was found to contain a CT-rich stretch, two CAAT boxes and a consensus TATA box. In addition, the transcript of the GPD gene was found to be expressed constitutively and strongly. These results suggest that the promoter of the L. edodes GPD gene may be very useful as a component of transformation vectors.

Hepatocyte growth inhibitory factor derived from HTLV-I(+) T-cell line is identical to IL-6

We previously reported that the culture supernatant of the human T-cell leukemia virus (HTLV-I) infected-T-cell line--ATL-2--included factor(s), which had an inhibitory effect on epidermal growth factor (EGF)-stimulated proliferation of primary cultured rat hepatocytes. After crude purification, we arbitrarily named it hepatocyte growth inhibitory factor (HGI). In this study, we further purified HGI and determined its amino acid sequence. For purification, we used 4-steps column chromatography and SDS-PAGE. The purified proteins consisted of two bands of 20 and 27 kDa in SDS-PAGE analysis. Protein extracted from each band had an inhibitory effect on rat hepatocyte growth. Amino acid analysis of the purified 20 kDa band revealed that the 34 amino acids were identical to those of IL-6. The inhibitory effect of the factor was neutralized by an anti IL-6 neutralizing antibody. Using Western blot analysis of HGI, an anti IL-6 antibody recognized both 20 and 27 kDa bands. Consequently HGI was determined to be identical to IL-6, which occurred in higher levels in the sera of adult T-cell leukemia (ATL) patients.

[A study of hypertriglyceridemia occurring in patients with chronic hepatitis C during administration of interferon beta]

The prevalence and risk factors of hypertriglyceridemia during the administration of interferon (IFN) were examined in 78 patients with chronic hepatitis C who were treated with 6 MU of IFN-beta once or 3 MU of IFN-beta twice a day for 6 weeks. Hypertriglyceridemia (serum triglyceride (TG) above 150 mg/dl) was found before the start of IFN treatment in 9% of the patients. During the administration of IFN, elevation of serum TG above 150 mg/dl was found in 82% of patients. In addition, serum TG level exceeded 500 mg/dl at least once during the administration of IFN in 13% of patients. On stepwise multiple regression analysis, three risk factors, high serum TG value before the administration of IFN, high ALT value before the administration of IFN, and divided administration of IFN-beta twice daily were found to be associated with hypertriglyceridemia during IFN administration.

Rho-associated kinase of chicken gizzard smooth muscle

Rho-associated kinase (Rho-kinase) from chicken gizzard smooth muscle was purified to apparent homogeneity (160 kDa on SDS-polyacrylamide gel electrophoresis) and identified as the ROKalpha isoform. Several substrates were phosphorylated. Rates with myosin phosphatase target subunit 1 (MYPT1), myosin, and the 20-kDa myosin light chain were higher than other substrates. Thiophosphorylation of MYPT1 inhibited myosin phosphatase activity. Phosphorylation of myosin at serine 19 increased actin-activated Mg+-ATPase activity, i.e. similar to myosin light chain kinase. Myosin phosphorylation was increased at higher ionic strengths, possibly by formation of 6 S myosin. Phosphorylation of the isolated light chain and myosin phosphatase was decreased by increasing ionic strength. Rho-kinase was stimulated 1.5-2-fold by guanosine 5'-O-3-(thio)triphosphate.RhoA, whereas limited tryptic hydrolysis caused a 5-6-fold activation, independent of RhoA. Several kinase inhibitors were screened and most effective were Y-27632, staurosporine, and H-89. Several lipids caused slight activation of Rho-kinase, but arachidonic acid (30-50 microM) induced a 5-6-fold activation, independent of RhoA. These results suggest that Rho-kinase of smooth muscle may be involved in the contractile process via phosphorylation of MYPT1 and myosin. Activation by arachidonic acid presents a possible regulatory mechanism for Rho-kinase.

BLNK required for coupling Syk to PLC gamma 2 and Rac1-JNK in B cells

Signaling through the B cell receptor (BCR) is essential for B cell function and development. Despite the key role of Syk in BCR signaling, little is known about the mechanism by which Syk transmits downstream effectors. BLNK (B cell LiNKer protein), a substrate for Syk, is now shown to be essential in activating phospholipase C (PLC)gamma 2 and JNK. The BCR-induced PLC gamma 2 activation, but not the JNK activation, was restored by introduction of PLC gamma 2 membrane-associated form into BLNK-deficient B cells. As JNK activation requires both Rac1 and PLC gamma 2, our results suggest that BLNK regulates the Rac1-JNK pathway, in addition to modulating PLC gamma 2 localization.

Ulcerative colitis with skip lesions at the mouth of the appendix: a clinical study

OBJECTIVE

We examined the clinical characteristics of ulcerative colitis patients who demonstrated endoscopically discontinuous lesions at the mouth of the appendix.

METHODS

Of patients with initial or recurrent active ulcerative colitis who underwent total colonoscopy during the past 3 yr at Osaka City General Hospital, we selected those who had skip lesions in the mouth of the appendix before treatment, and examined their gender, age, disease type, sites of lesions, inflammatory reaction, severity of disease, effects of treatment, and posttreatment course.

RESULTS

Discontinuous lesions at the mouth of the appendix were found in 10 patients, who had the following common clinical features: the major lesion was usually present in the lower part of the large bowel including the rectum, many of the patients had suffered an initial attack only, all patients had mild disease, and many of the patients responded quite satisfactorily to treatment with salicylazosulfapyridine.

CONCLUSION

Numerous patients with ulcerative colitis with discontinuous lesions at the mouth of the appendix were observed and their clinical characteristics were examined. Determination of the clinical significance of skip lesions in the appendix will contribute to elucidation of the pathogenesis of ulcerative colitis.

Encephalopathy and cytomegalovirus colitis in an AIDS child

A 2-year-old girl, who had prolonged thrush and spastic diplegia, was found to have a mother-to-child vertical transmission of human immunodeficiency virus type-1 (HIV). A brain computed tomography scan revealed a symmetrical calcification on the bilateral basal ganglia and periventricular white matter. She had an acquired immune deficiency syndrome (AIDS) encephalopathy of pure dominant pyramidal tract disorder without an intellectual deficit. Helper cell lymphocyte count (CD4) increased with the beginning of zidovudine (ZDV, also known as AZT) monotherapy but began to decrease after the 4th week to reach the baseline at 20th week. Zidovudine plus didanosine combination therapy was started at the 68th week, but because of intolerance, the combination was changed to ZDV plus lamivudine at the 98th week. By the 80th week, neither severe opportunistic infection nor deterioration of the neurological status was recognized, but chronic diarrhea appeared. The diarrhea advanced to the wasting syndrome at the age of 4 years and cytomegalovirus genome was confirmed in a biopsied specimen of the colon. Ganciclovir treatment was effective in stopping the diarrhea and increasing her bodyweight, but after the age of 5, resumption of diarrhea was followed by progressive emaciation and weakness. This work may provide some clues in treating children's AIDS.

[A case report of esophageal carcinoma with grade 3 response by preoperative chemotherapy using CDDP/5-FU/LV]

A 67-year-old man was diagnosed as having a type 3 advanced esophageal carcinoma by barium swallow and endoscopy. Biopsy specimens showed well-differentiated squamous cell carcinoma with positive immunostaining for p53, C-erb B-2 and negative for bcl-2. Two courses of chemotherapy using 5-FU, leucovorin and CDDP were performed before operation. Because no cancer cells were present in the surgical specimens, the effect was evaluated as grade 3. This neoadjuvant chemotherapy may be effective for esophageal carcinoma with a possible apoptosis mechanism.

Specific detection of phosphatidylinositol 3,4,5-trisphosphate binding proteins by the PIP3 analogue beads: an application for rapid purification of the PIP3 binding proteins

Phosphatidylinositol (PI) 3-kinase is known as one of the key molecules involved in the various biological events such as vesicle trafficking, cytoskeletal rearrangements and cell survival. T clarify the molecular basis underlying these events, we have tried to identify the proteins that can interact with phosphatidylinositol 3,4,5-trisphosphate (PIP3), the lipid product of PI3-kinase. Using a new PIP3 analogue, PIP3-APB, we synthesized an affinity column for PIP3 binding proteins. This enabled us to purify and identify several PIP3 binding proteins such as Tec tyrosine kinase, Gap1m, and Akt, as the candidates for the downstream molecules of PI3-kinase. All of these proteins contain PH domains, possible binding sites for phospholipids. Studies with various deletion mutants of Tec or Gap1m revealed that their PH domains are indeed the binding sites for PIP3. These results demonstrate that this PIP3-analogue binds various PIP3 binding proteins with high specificity and may be useful to elucidate the downstream mechanisms of PI3-kinases-mediated signaling pathways.

Katanin, a microtubule-severing protein, is a novel AAA ATPase that targets to the centrosome using a WD40-containing subunit

Microtubule disassembly at centrosomes is involved in mitotic spindle function. The microtubule-severing protein katanin, a heterodimer of 60 and 80 kDa subunits, was previously purified and shown to localize to centrosomes in vivo. Here we report the sequences and activities of the katanin subunits. p60 is a new member of the AAA family of ATPases, and we show that expressed p60 has microtubule-stimulated ATPase and microtubule-severing activities in the absence of p80. p80 is a novel protein containing WD40 repeats, which are frequently involved in protein-protein interactions. The p80 WD40 domain does not participate in p60 dimerization, but localizes to centrosomes in transfected mammalian cells. These results indicate katanin's activities are segregated into a subunit (p60) that possesses enzymatic activity and a subunit (p80) that targets the enzyme to the centrosome.

Regulation of the association of adducin with actin filaments by Rho-associated kinase (Rho-kinase) and myosin phosphatase

The small GTPase Rho is believed to regulate the actin cytoskeleton and cell adhesion through its specific targets. We previously identified the Rho targets: protein kinase N, Rho-associated kinase (Rho-kinase), and the myosin-binding subunit (MBS) of myosin phosphatase. Here we purified MBS-interacting proteins, identified them as adducin, and found that MBS specifically interacted with adducin in vitro and in vivo. Adducin is a membrane-skeletal protein that promotes the binding of spectrin to actin filaments and is concentrated at the cell-cell contact sites in epithelial cells. We also found that Rho-kinase phosphorylated alpha-adducin in vitro and in vivo and that the phosphorylation of alpha-adducin by Rho-kinase enhanced the interaction of alpha-adducin with actin filaments in vitro. Myosin phosphatase composed of the catalytic subunit and MBS showed phosphatase activity toward alpha-adducin, which was phosphorylated by Rho-kinase. This phosphatase activity was inhibited by the phosphorylation of MBS by Rho-kinase. These results suggest that Rho-kinase and myosin phosphatase regulate the phosphorylation state of adducin downstream of Rho and that the increased phosphorylation of adducin by Rho-kinase causes the interaction of adducin with actin filaments.

Systemic and pulmonary responses of inflammatory cytokines following esophagectomy

Inflammatory cytokines in plasma and bronchoalveolar lavage fluid (BALF) from 16 post-esophagectomy patients with and without preoperative methylprednisolone administration were studied. Interleukin-8 (IL-8), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) concentrations in plasma and BALF were measured by ELISA immediately after surgery (0-POD) and on the postoperative day 1 (1-POD). In patients without methylprednisolone treatment, IL-8 levels in BALF were 362 +/- 67 pg/ml on 0-POD and 948 +/- 359 pg/ml on 1-POD, and were approximately 10 times higher than those in plasma levels. IL-6 levels in plasma were significantly higher than those in BALF. The TNF-alpha concentration was similarly low in plasma and BALF. The patients with preoperative methylprednisolone treatment had significantly lower IL-8 levels in BALF and plasma compared with the patients without the treatment. Immunocytochemically, each cytokine was identified in the cytoplasm of bronchoalveolar macrophage. The percentage of polymorphonuclear cells (PMN) among BAL cells was significantly increased on 1-POD when compared with that of 0-POD, and tended to be decreased by preoperative methylprednisolone treatment. These results suggest that IL-6 was markedly increased in the peripheral circulation and that increased pulmonary IL-8 might be related to an accumulation of PMN in the lung under surgical stress. Further, methylprednisolone administration could possibly reduce postoperative cytokine responses at the local and systemic levels.

A caspase-activated DNase that degrades DNA during apoptosis, and its inhibitor ICAD

The homeostasis of animals is regulated not only by the growth and differentiation of cells, but also by cell death through a process known as apoptosis. Apoptosis is mediated by members of the caspase family of proteases, and eventually causes the degradation of chromosomal DNA. A caspase-activated deoxyribonuclease (CAD) and its inhibitor (ICAD) have now been identified in the cytoplasmic fraction of mouse lymphoma cells. CAD is a protein of 343 amino acids which carries a nuclear-localization signal; ICAD exists in a long and a short form. Recombinant ICAD specifically inhibits CAD-induced degradation of nuclear DNA and its DNase activity. When CAD is expressed with ICAD in COS cells or in a cell-free system, CAD is produced as a complex with ICAD: treatment with caspase 3 releases the DNase activity which causes DNA fragmentation in nuclei. ICAD therefore seems to function as a chaperone for CAD during its synthesis, remaining complexed with CAD to inhibit its DNase activity; caspases activated by apoptotic stimuli then cleave ICAD, allowing CAD to enter the nucleus and degrade chromosomal DNA.

Regulation of cross-linking of actin filament by IQGAP1, a target for Cdc42

We have previously shown that IQGAP1, a recently identified target for Cdc42 and Rac1 small GTPases, showed a distribution similar to that of cortical actin cytoskeleton at the membrane ruffling area induced by insulin and Rac1(val12) (Kuroda, S., Fukata, M., Kobayashi, K., Nakafuku, M., Nomura, N., Iwamatsu, A., and Kaibuchi, K. (1996) J. Biol. Chem. 271, 23363-23367). Here we identified an IQGAP1-interacting molecule with molecular mass of 43 kDa (p43) from bovine brain cytosol, using glutathione S-transferase (GST)-IQGAP1 affinity column chromatography. The amino acid sequencing of the protein revealed that p43 was identical to beta- and gamma-actin. IQGAP1 was cosedimentated with filamentous actin (F-actin). The amino-terminal domain (amino acids 1-216) of IQGAP1 was responsible for the interaction with F-actin. Falling ball viscometry assay revealed that IQGAP1 cross-linked the F-actin. This IQGAP1 activity was further enhanced by guanosine 5'-(3-O-thio)triphosphate (GTPgammaS).GST-Cdc42 but not by GDP.GST-Cdc42. The gel filtration analysis of IQGAP1 revealed that IQGAP1 appeared as oligomers and that GTPgammaS.GST-Cdc42 but not GDP.GST-Cdc42 enhanced the oligomerization of IQGAP1. These results strongly suggest that IQGAP1, acting downstream of Cdc42, can cross-link the actin filament through its oligomerization.

Endoscopic dexamethasone injection following balloon dilatation of anastomotic stricture after esophagogastrostomy

BACKGROUND

Anastomotic stricture is common after esophagogastrostomy. Recent advances in nonsurgical treatment include the silicon bougie and balloon dilatation. However, simple dilatation alone with a silicon bougie or endoscopic balloon dilator was repeated a mean of 4.7+/-5.4 times to control anastomotic stricture because of its temporary effect.

METHODS

For 11 patients, endoscopic injection of dexamethasone (8 mg) around the anastomosis was done immediately after balloon dilatation (40 psi for 5 minutes).

RESULTS

This method significantly reduced the number of the dilatations to 1.1+/-0.3 (P < 0.05). Ten of the 11 patients did not need any further treatment. There were no side effects or complications of dexamethasone injection.

CONCLUSION

A combination of endoscopic balloon dilatation and dexamethasone injection provided an easy and safe method for preventing the recurrence of anastomotic stricture.

Cytotoxin genes of Helicobacter pylori in chronic gastritis, gastroduodenal ulcer and gastric cancer: an age and gender matched case-control study

Helicobacter pylori (H. pylori) infection is involved in many gastrointestinal diseases, such as chronic gastritis (CAG), peptic ulcer and gastric cancer (GCA). Both host factors and H. pylori strain differences may contribute to differences in the diseases. Thus, we conducted an age and gender matched case-control study of 35 patients each with CAG, gastric ulcer (GUL), duodenal ulcer (DUL) and gastric cancer (GCA) to examine the role of strain differences of the H. pylori cytotoxin genes cagA and vacA in these diseases. We employed polymerase chain reaction to examine the gastric juice for H. pylori DNA. The test was positive for 26 (74.3%) CAG, 29 (82.9%) GUL, 28 (80.0%) DUL and 27 (77.1%) GCA patients, showing no statistically significant difference among the diseases (P = 0.84). cagA and vacA genes (picked up by using a vacA1 + vacA2 primer pair which detected non-variable regions of the vacA gene) were detected by PCR in the H. pylori DNA-positive cases as follows: CAG, 92.3% and 76.9%; GUL, 100% and 86.2%; DUL, 89.3% and 89.3%; GCA, 92.6% and 85.2%, respectively. No statistically significant differences were found in the frequencies of these cytotoxin genes in H. pylori-positive cases among the various gastric diseases (P = 0.39 for cagA and P = 0.64 for vacA).

Effect of bucillamine on the rat trinitrobenzene sulfonic acid induced model of colitis

Salicylazosulphapyridine and corticosteroids are the only remedies for inflammatory bowel disease currently in clinical use. They do not, however, necessarily bring about satisfactory therapeutic benefits, so that new agents are needed. In this study, we evaluated the effect of bucillamine, a new antirheumatic agent, in experimental rat colitis induced by trinitrobenzene sulfonic acid enema. Wistar rats were given vehicle alone (n = 16) or treated with 50 (n = 20) or 150 (n = 20) mg/kg of bucillamine daily for three weeks after induction of colitis. Conventional histological sections of the colon stained by haematoxylin and eosin were prepared and observed under a light microscope to determine colonic damage scores. The determinations were significantly lower in the group treated with 50 mg/kg of bucillamine and tended to be lower in the group treated with 150 mg/kg of bucillamine than in the untreated group, which implied that the experimentally induced colonic inflammatory changes and ulcerations were alleviated by bucillamine. Blood tests showed no abnormal values at the end of the treatment. The present observations suggest that bucillamine should be developed further as a possible therapy for inflammatory bowel disease.

Regulation of myosin phosphatase by Rho and Rho-associated kinase (Rho-kinase)

The small guanosine triphosphatase Rho is implicated in myosin light chain (MLC) phosphorylation, which results in contraction of smooth muscle and interaction of actin and myosin in nonmuscle cells. The guanosine triphosphate (GTP)-bound, active form of RhoA (GTP.RhoA) specifically interacted with the myosin-binding subunit (MBS) of myosin phosphatase, which regulates the extent of phosphorylation of MLC. Rho-associated kinase (Rho-kinase), which is activated by GTP.RhoA, phosphorylated MBS and consequently inactivated myosin phosphatase. Overexpression of RhoA or activated RhoA in NIH 3T3 cells increased phosphorylation of MBS and MLC. Thus, Rho appears to inhibit myosin phosphatase through the action of Rho-kinase.

[Percutaneous microwave coagulation therapy for hepatocellular carcinoma--study on its therapeutic effect in surgical cases]

Six patients with hepatocellular carcinoma were subjected to percutaneous microwave coagulation therapy (PMCT) by ultrasonic guiding. The size of the main tumor in the present cases was limited to not more than 2 cm. From 18 to 48 days after PMCT, each patient was subjected to surgery and pathological examination. By macroscopic observation, the PMCT area including both non-tumor and tumor regions looked yellowish white, and the boundary was clearly recognized. In the histological examination, the coagulation area surrounded by fibrous capsule was found, and deletion of nuclei and changes in stainability were observed in the marginal region. These changes indicated obvious coagulation necrosis, but the changes became less intense toward the center in the area, and in some portions, the tissue was indistinguishable from viable cells by light microscopy. In 2 cases out of the 6, part of the tumor remained outside the coagulation area. Since only the area determined by the microwave electrode is coagulated to cause necrosis on PMCT, sufficient safety margin should be required.

Rho-associated kinase, a novel serine/threonine kinase, as a putative target for small GTP binding protein Rho

The small GTP binding protein Rho is implicated in cytoskeletal responses to extracellular signals such as lysophosphatidic acid to form stress fibers and focal contacts. Here we have purified a Rho-interacting protein with a molecular mass of approximately 164 kDa (p164) from bovine brain. This protein bound to GTPgammaS (a non-hydrolyzable GTP analog).RhoA but not to GDP.RhoA or GTPgammaS.RhoA with a mutation in the effector domain (RhoAA37).p164 had a kinase activity which was specifically stimulated by GTPgammaS.RhoA. We obtained the cDNA encoding p164 on the basis of its partial amino acid sequences and named it Rho-associated kinase (Rho-kinase). Rho-kinase has a catalytic domain in the N-terminal portion, a coiled coil domain in the middle portion and a zinc finger-like motif in the C-terminal portion. The catalytic domain shares 72% sequence homology with that of myotonic dystrophy kinase and the coiled coil domain contains a Rho-interacting interface. When COS7 cells were cotransfected with Rho-kinase and activated RhoA, some Rho-kinase was recruited to membranes. Thus it is likely that Rho-kinase is a putative target serine/threonine kinase for Rho and serves as a mediator of the Rho-dependent signaling pathway.

The small GTP-binding protein Rho binds to and activates a 160 kDa Ser/Thr protein kinase homologous to myotonic dystrophy kinase

The small GTP-binding protein Rho functions as a molecular switch in the formation of focal adhesions and stress fibers, cytokinesis and transcriptional activation. The biochemical mechanism underlying these actions remains unknown. Using a ligand overlay assay, we purified a 160 kDa platelet protein that bound specifically to GTP-bound Rho. This protein, p160, underwent autophosphorylation at its serine and threonine residues and showed the kinase activity to exogenous substrates. Both activities were enhanced by the addition of GTP-bound Rho. A cDNA encoding p160 coded for a 1354 amino acid protein. This protein has a Ser/Thr kinase domain in its N-terminus, followed by a coiled-coil structure approximately 600 amino acids long, and a cysteine-rich zinc finger-like motif and a pleckstrin homology region in the C-terminus. The N-terminus region including a kinase domain and a part of coiled-coil structure showed strong homology to myotonic dystrophy kinase over 500 residues. When co-expressed with RhoA in COS cells, p160 was co-precipitated with the expressed Rho and its kinase activity was activated, indicating that p160 can associate physically and functionally with Rho both in vitro and in vivo.