K+-independent initiation of motility in chum salmon sperm treated with an organic alcohol, glycerol

Sperm of salmonid fishes are quiescent in the presence of millimolar concentrations of extracellular K+, but motility initiation occurs when sperm are suspended in K+-free medium. In this study, glycerol (CH2OHCHOHCH2OH) treatment of intact sperm in the presence of K+ induced the initiation of motility even though a large amount of K+ was present. Another organic alcohol, erythritol (CH2OH(CHOH)2CH2OH), had a similar effect, but ethylene glycol (CH2OHCH2OH) did not initiate sperm motility. Furthermore, this glycerol-treated sperm showed motility without subsequent addition of ATP and cAMP. CCCP, an uncoupler of the mitochondrial electron-transport chain involved in ATP synthesis, suppressed motility of glycerol-treated sperm, suggesting that ATP synthesis is required for dynein to slide microtubules in glycerol-treated sperm. The amount of intracellular cAMP ([cAMP]i) in glycerol-treated sperm did not increase on motility activation, but a protein kinase A (PKA) inhibitor, H-89, inhibited glycerol-treated sperm motility. In addition, phosphorylation of protein associated with motility initiation also occurred in glycerol-treated sperm, suggesting that the glycerol treatment induces activation of PKA without an increase in [cAMP]i. Taken together, it can be concluded that organic alcohol, glycerol and erythritol induce phosphorylation for motility initiation, bypassing the increase in [cAMP]i as a result of a decrease in extracellular K+ concentration.

222 METHYLATION OF THE 52-UPSTREAM REGION OF THE H19 GENE IN MOUSE SOMATIC CELL, GAMETES, WILD TYPE AND ANDROGENETIC ES CELLS

In mammals, several genes influenced by the phenomenon of genomic imprinting are critical during development. Recently, Kono et al. (2004 Nature 428, 860–864) reported the production of intact female mouse individuals that had only two haploid sets of maternal genome. They obtained these mice by combining a normal haploid maternal genome and a mutant haploid maternal genome with a 13 k base deletion in the H19 gene and its 5′-upstream region. This genomic combination resulted in the appropriate expression of the Igf2, H19, and other imprinted genes. In the mouse genome, there are four CTCF-binding sites in the 5′-upstream region of the H19 gene. The binding of CTCF to these binding sites regulates the expression of the Igf2 and H19 genes. The binding of CTCF to its binding sites is regulated by methylation of CpG sites in binding sites. In this study, as the first step to elucidate the role of the paternal genomic imprinting during development, we investigated the methylation of CpG sites in the 5′-upstream region of the H19 gene in mouse somatic cells, gametes, and two types of ES cells. Genomic DNA was isolated from BDF1 (C57BL/6N × DBA/2N) mouse's tail (male and female somatic tissue, mST and fST, respectively), spermatozoa (S), oocytes (O), and wild type and androgenetic embryonic stem cells (wtES and agES, respectively). The methylation of CpG sites was evaluated by using the bisulfite sequencing assay. There were 13 CpG sites and a CTCF-binding site in the region from −4413 to −3976 in the H19 gene relative to the transcription start site. The percentages of CpG sites in this region that were methylated were 88% (160/182), 79% (27/130), 93% (230/247), 8% (10/130), 77% (10/13) and 89% (314/351) for mST, fST, S, O, wtES, and agES, respectively. In the CTCF-binding site core motif (CCGCGTGGTGGCAG), the percentages of methylated CpG sites were 93% (26/28), 80% (16/20), 95% (36/38), 0% (0/20), 50% (1/2) and 96% (52/54) for mST, fST, S, O, wtES, and agES, respectively. The CpG sites in the sequence of agES were highly methylated similar to the finding in spermatozoa. However, an aberrant methylation pattern was observed in some clones of agES. From these results, it was concluded that the methylation of CpG sites in the genomic sequence of agES was well conserved and, therefore, agES is useful to elucidate the role of the paternal genomic imprinting during development. This work was supported by Wakayama Prefecture Collaboration of Regional Entities for the Advanced of Technological Excellence, Japan, and by a Grant-in-Aid for the 21st Century COE Program of the Japan MEXT.

Requirement of Ca2+ on activation of sperm motility in euryhaline tilapia Oreochromis mossambicus

Euryhaline tilapia Oreochromis mossambicus acclimates to the external spawning environment by modulating its mechanism for regulating sperm motility. Adaptation of sperm was performed by acclimating fish in various environments. In this paper, regulatory mechanisms of freshwater-acclimated tilapia were studied in detail. Tilapia sperm motility was vigorous in hypotonic conditions and decreased with increasing osmolality. Sperm motility was reduced in hypotonic conditions when extracellular Ca(2+) was chelated; however, extracellular Ca(2+) was not a major factor for motility activation since sperm were motile even when extracellular Ca(2+) levels were nominally depleted by EGTA. The Ca(2+) indicator, fluo 3, showed that intracellular [Ca(2+)] increased on motility activation independently of extracellular [Ca(2+)], accompanied by swelling of the sperm neck region called the sleeve structure. Intracellular [Ca(2+)] was not increased under hypertonic conditions, in which sperm were immotile, even on addition of extracellular Ca(2+). It is possible that Ca(2+) is stored in the neck region. Demembranated sperm were reactivated in the presence of Ca(2+), but cAMP failed to reactivate the motility. Furthermore, we detected phosphorylation and dephosphorylation of three proteins at serine and threonine residues on motility activation. It is likely that hypotonic shock causes an increase in intracellular [Ca(2+)] that activates motility activation via phosphorylation of some flagellar proteins.

Bioresorbable devices made of forged composites of hydroxyapatite (HA) particles and poly L-lactide (PLLA). Part II: practical properties of miniscrews and miniplates

Miniscrews and miniplates made of forged composites composed of raw hydroxyapatite (u-HA) particles (particle size 0.2-20 microm, averaging 3.0 microm, Ca/p = 1.69 and containing CO3(2-)) and a poly L-lactide (PLLA, Mv: about 180 kDa, containing residual 0.05 wt% lactide) with osteological bioactivity such as direct bonding to bone and osteoconductivity, total resorbability and radiopacity were examined for various mechanical properties in order to evaluate their usefulness for cranio-, oral and maxillo-facial as well as plastic and reconstructive surgeries with PLLA-only or titanium devices. The composites containing u-HA particles at 30wt% for miniscrews and 40wt% for miniplates were selected based on total mechanical strengths and bioactivity, respectively. It was found that the composite devices generally had slightly different mechanical properties than forged PLLA-only devices of which strengths are ranked the highest among the reinforced PLLA-only ones that having been used in many clinical cases to date, in spite of their approximate 2 or 3 times lower absolute strengths than those of titanium ones. However, a remarkable distinction that makes the composite miniplates stand above the titanium ones was confirmed on their fatigue resistance to alternate bendings such that they retained 70% of their initial strength even after 60 times without revealing any damage, whereas the metallic devices fully broke off at only 8 times. This behavior was similar to that of forged PLLA-only devices but is unique as composites made of organic polymers divided by inorganic particles. In addition, profile plates such as L-, T-, X, T, C-, Mesh-, Box-, and Barhole types which were processed by forging twice exhibited nearly directional isotropy in strength and could be deformed in situ at ordinary temperatures to adjust their shapes along the surface undulations of the skull, mandible, maxilla, zygomatic bone and the like without thermoforming and did not return to their original shapes inside an alive body due to the high PLLA's Tg (65 degrees C) over an alive body temperature (37 degrees C). Since it had already been confirmed in previous papers that these stiff and tough composites have the osteological bioactivity which is missing from both PLLA-only and titanium ones, and radiopacity which is wanting in PLLA-only ones, these various small and thin screws and plates have conclusively less objectionable practicality for use in oral-maxillo and craniofacial as well as plastic and reconstructive surgeries.

Different mutation status of the beta-catenin gene in carcinogen-induced colon, brain, and oral tumors in rats

Mutations in the region corresponding to the N-terminal phosphorylation sites (codons 1-51) of the rat beta-catenin gene (Ctnnb1) were investigated in rat colon tumors induced by 1-hydroxyanthraquinone (1-HA) plus methylazoxymethanol (MAM) acetate, by using polymerase chain reaction (PCR)-single-strand conformation polymorphism (SSCP) analysis. The beta-catenin gene was also screened for mutations in rat brain and oral tumors induced by ethyl nitrosourea (ENU) and 4-nitroquinoline 1-oxide (4-NQO), respectively. In colon tumors, beta-catenin gene mutations were found in two of three adenomas (67%) and 26 of 28 adenocarcinomas (93%), with a total incidence of 90% (28 of 31 adenomas plus adenocarcinomas). Eight (29%) were (34)G-->T (second position), eight (29%) were (32)G-->A (first position), five (18%) were (34)G-->A (first position), five (18%) were (41)C-->T (second position), one (4%) was (34)G-->A (second position), and one (4%) was (32)A-->G (second position), mutations, resulting in the substitutions of Gly(34)-->Val, Asp(32)-->Asn, Gly(34)-->Arg, Thr(41)-->Ile, Gly(34)-->Glu, and Asp(32)-->Gly, respectively. The (34)G-->T (second position) mutations found in this study were unique compared to those found in other carcinogen-induced rat colon carcinogenesis models. In contrast, beta-catenin gene mutations were not found in either the brain or oral tumors. These results suggest that mutations in the beta-catenin gene in rat tumors occur in specific tissues or organ sites and in a carcinogen-specific manner. Thus, the mutation spectrum in the beta-catenin gene is organ- and chemical carcinogen-specific.

Chemoprevention of hepatocellular carcinoma: concept, progress and perspectives

Hepatocellular carcinoma (HCC) often develops in patients with chronic liver diseases associated with hepatitis B (HBV) and hepatitis C (HCV) virus infections with high incidences. Particularly, post-therapeutic recurrence encountered after the curative treatment of the preceding HCC may limit the prognosis. Thus, prevention of HCC is of great significance. In the present review, immunopreventions with alpha-interferon and glycyrrhizin, as well as chemoprevention with acyclic retinoid, are discussed. alpha-Interferon prevents the development of HCC not only in patients with a long-term elimination of HCV (sustained virological responders), but in ones with normalized serum aminotransferases (sustained biochemical responders). Glycyrrhizin also suppresses serum aminotransferases and thereby prevents the tumor development, even though the compound does not have antiviral activity for HBV or HCV by itself. Therefore, suppression of hepatic necroinflammation by these drugs may serve to prevent hepatocarcinogenesis. In contrast, acyclic retinoid suppresses the post-therapeutic recurrence in cirrhotic patients who underwent curative treatment of preceding tumors. The retinoid induces the disappearance of serum lectin-reactive alpha-fetoprotein (AFP-L3), a tumor marker indicating the presence of unrecognizable tumors in the remnant liver, suggesting a deletion of such minute (pre)malignant clones (clonal deletion). As a molecular mechanism of the clonal deletion, a novel mechanism of apoptosis induction by the retinoid via tissue transglutaminase is implicated. In future, a combination of immunopreventive and chemopreventive therapies may give a clue to the further advances of cancer prevention, and thereby to the improvement of the prognosis of cirrhotic patients.

Phosphorylation of retinoid X receptor alpha at serine 260 impairs its metabolism and function in human hepatocellular carcinoma

Retinoids induce apoptosis and differentiation of hepatocellular carcinoma (HCC) cells and are used clinically in the chemoprevention of HCC. We have shown previously that hepatocarcinogenesis is accompanied by accumulation of full-length retinoid X receptor alpha (RXRalpha), although the underlying mechanisms and biological implications have remained unclear. The present studies were based on the finding that the accumulated full-length RXRalpha was phosphorylated at serine/threonine residues both in all human HCC tissues examined and in human HCC-derived HuH7 cells. Phosphorylation at serine 260 of RXRalpha, a consensus site of mitogen-activated protein kinase, was closely linked to its retarded degradation, low transactivating activity, and the promotion of cancer cell growth. There was no genomic mutation in the RXRalpha gene, and abrogation of phosphorylation by mitogen-activated protein kinase-specific inhibitors restored the degradation of RXRalpha in an RXR ligand-dependent manner. These results suggest that phosphorylation of RXRalpha may interfere with its metabolism and signaling in human HCC, which could lead to growth promotion of these tumors.

Japanese red-bellied newts in Space--AstroNewt experiment on Space Shuttle IML-2 and Space Flyer Unit

Biological effects of gravity was examined in embryonic development of Japanese red bellied newt. Two space newt missions were conducted in 1994 and 1995. The Second International Microgravity Laboratory was flown in 1994 as one of the SpaceLab missions. Space Flyer Unit, a Japanese space platform, was delivered to the earth orbit by the third launch of the H-II rocket and retrieved by Space Shuttle in 1996. Female newts were induced to lay eggs in orbit at these two space missions. Eggs were successfully obtained on both missions, and exposed to space environment from its early developmental stages. Morphology of the embryos was found not deviated from those developed on ground, as long as in the images taken in orbit or the examined specimen retrieved to ground. On the other hand, pathological changes were discovered in several organs of the adult newts that returned alive from their space flight.

Apoptosis induction by acyclic retinoid: a molecular basis of 'clonal deletion' therapy for hepatocellular carcinoma

We have shown previously that administration of acyclic retinoid to cirrhotic patients who had undergone curative treatment of preceding hepatocellular carcinoma (HCC) induced the disappearance of serum lectin-reactive alpha-fetoprotein (AFP-L3) and subsequently reduced the incidence of second liver cancers. AFP-L3 is a tumor marker that indicates the presence of occult tumors below the detection limit by diagnostic images. Therefore, we have proposed a new concept of 'clonal deletion' therapy with acyclic retinoid for the cancer chemoprevention against HCC. Such eradication of AFP-L3-producing latent malignant (or premalignant) cells from the liver suggested a new strategy to prevent HCC, which may be involved in the same category as cancer chemotherapy. In the present series of studies, we explored the molecular mechanism of 'clonal deletion' and found a novel mechanism of apoptosis induction by the retinoid. We have demonstrated a modification of a retinoid receptor, RXRalpha, by mitogen-activated protein (MAP) kinase-dependent phosphorylation, resulting in the loss of transactivating activity. This may lead HCC cells to be resistant to natural retinoic acid. However, acyclic retinoid restored the function of phosphorylated RXRalpha and induced its downstream pro-apoptotic genes including tissue transglutaminase, an enzyme that is implicated in apoptosis. Tissue transglutaminase-dependent apoptosis in HCC cells was independent of the activation of caspases. This novel mechanism of retinoid-induced apoptosis may give a clue to understand the molecular mechanism of clonal deletion.

A comparison of vibration magnitudes on the tool with different subject according to the ISO 8662-7 standard

Recently, ISO has defined the guidelines for the evaluation of the measurement and exposure limits of hand-transmitted vibrations at the handle of hand-held portable power tools. In a measurement of vibrations at pneumatic impact wrenches that tighten and remove screws. ISO 8862-7 standard: 1997 and ISO 5349 standard: 1986 are set as international standards. In order to make an exact measurement of the quantities of vibrations exposed to the hand-arm system of a human body, ISO 8662-7 gives specifications to a measurement device and a loading device. As to a measurement device, for instance, the mass, installation method etc. of transducers and mechanical filters are defined. In addition, it specifies with each tolerance the working conditions of a pneumatic tool, the number of revolutions of socket in a loading device, the feed force, the number of subjects, and such an evaluation method as how to decide a declaration value of vibrations. These specifications give toolmakers a comparative measurement of vibration values of their tools before shipment. Meanwhile, although the measurement condition described in ISO8662-7: 1997 is that skilled operators conduct vibration measurement, no provisions as to operators are made in detail. Hence, this study focuses its concern on ambiguous work experience years in measuring vibrations of the tools in conformity with ISO 8662-7, and hereby the effect of years of work experience upon measurement values is considered and at the same time a knowledge of how to select operators is made clear.

Prevention of rat hepatic fibrosis by the protease inhibitor, camostat mesilate, via reduced generation of active TGF-beta

BACKGROUND & AIMS

Proteolytic release and activation of latent transforming growth factor beta (TGF-beta) by the hepatic stellate cells (HSCs) are key events for pathogenesis of hepatic fibrosis, and protease inhibitors suppress TGF-beta generation by cultured HSCs, suggesting their potential use as antifibrogenic agents. We explored this idea using camostat mesilate, a serine protease inhibitor, to determine its effects and mechanisms of action in vivo.

METHODS

Camostat mesilate was either added to cultured rat HSCs or administered orally to rats during porcine serum treatment, followed by overexpression of urokinase. We measured cellular and hepatic levels of plasmin, TGF-beta, TGF-beta activity, activated HSC markers (increased cell number, morphologic change, and expression of both alpha-smooth muscle actin and collagen(alpha2)[I]), and fibrosis (Azan-staining and quantification of hydroxyproline content).

RESULTS

Camostat mesilate (500 micromol/L) inhibited generation of TGF-beta by suppressing plasmin activity and reduced the activity of TGF-beta, which blocked in vitro activation of HSCs. In the in vivo model, camostat mesilate (1-2 mg/g of diet) markedly attenuated an increase in hepatic plasmin and TGF-beta levels, HSC activation, and hepatic fibrosis without apparent systemic or local side effects, all of which were reverted by restoration of hepatic plasmin activity.

CONCLUSIONS

Camostat mesilate prevents porcine serum-induced rat hepatic fibrosis via a profound reduction in TGF-beta generation.

Ruptured dissecting aneurysm in bilateral iliac arteries caused by Ehlers-Danlos syndrome type IV: report of a case

Ehlers-Danlos syndrome (EDS) is an inherited disorder of connective tissue characterized by hyperextensible skin, hypermobile joints, and abnormalities of the cardiovascular system. Ten types and several subtypes of EDS have so far been recognized based on genetic, clinical, and biochemical characteristics. The spectrum of the disorder varies from mild to life-threatening vascular complications. EDS type IV is a particularly dangerous form with a lethal spontaneous rupture of the major arteries and aneurysmal formation. We present herein a case of a ruptured dissecting aneurysm in the bilateral iliac arteries caused by EDS type IV. A previously healthy 33-year-old man without any physical features of this connective tissue disorder experienced a metachronous vascular rupture two times. Successful synthetic bypass grafting was performed with great difficulty. The diagnosis of EDS type IV was made afterwards based on an electrophoresis analysis of a skin biopsy specimen which revealed a lack of type III collagen. Surgical intervention in cases of arterial complications in EDS type IV patients have been reported to be both difficult and frequently unsuccessful. The early clinical recognition of this syndrome is therefore of great importance due to the hazards of such surgical therapies.

Bernard-Soulier syndrome associated with 22q11.2 microdeletion

We describe a Japanese girl with Bernard-Soulier syndrome and 22q11.2 microdeletion. She had viral infections and recurrent thrombocytopenia and hemorrhagic diathesis after cardiac surgery. As congenital heart defects and abnormal immunity are the most common clinical manifestations associated with 22q11.2 deletion, patients with this association may have a greater risk of developing a severe bleeding disorder.

A comparative study of rural clinics in remote islands and inland areas

The social and professional isolation of physicians remains an important issue in rural areas. However, few studies have investigated the involvement of geographic factors in the isolation. This study investigates rural public clinics in inland and remote island locations and attempts to objectively compare the isolation of these physicians. A mailed questionnaire was sent to rural clinics where graduate physicians from Jichi Medical School were working in 1994 and 1995. Among the 198 clinics with one or more full-time physicians, 185 (93 percent) responded to the inquiry. Geographic and demographic factors of the communities were compared between 43 clinics located in remote islands and the other 142 rural inland clinics. Rural clinics in remote islands have smaller subject populations, fewer part-time physicians, a longer journey to the nearest city, and a longer distance and travel time to the base hospital than rural inland clinics. Physicians in remote island clinics had less medical training and are more isolated than other physicians. More than half of the clinic physicians in remote islands have no regular training schedule, in contrast to less than a quarter of the inland clinic physicians. Almost all clinics (97.7%) in remote islands do not have a part-time physician, whereas about 20 percent of the rural inland clinics do. Physicians in remote island clinics are more socially and professionally isolated than those in inland clinics. Strategies to reduce these problems should be given priority in rural health policy and measures tailored to rural clinics in remote islands.

Mechanism of retarded liver regeneration in plasminogen activator-deficient mice: impaired activation of hepatocyte growth factor after Fas-mediated massive hepatic apoptosis

Urokinase-type plasminogen activator (uPA) is implicated in the regulation of hepatic regeneration by activating hepatocyte growth factor (HGF). Here, we investigated its role in the hepatic regeneration after Fas-mediated massive hepatocyte death employing mice deficient in either uPA or its inhibitor, plasminogen activator inhibitor-1 (PAI-1). We measured kinetics of hepatic levels of proliferating cell nuclear antigen (PCNA)-labeling index, plasmin activity, mature HGF, and its phosphorylated receptor, c-Met. In the genetically targeted and wild-type mice, hepatocytes fell into the same extent of apoptosis 6 to 12 hours after an intraperitoneal injection with anti-Fas antibody, as judged from histologic analysis and a histon-DNA enzyme-linked immunosorbent assay (ELISA). In the wild-type mice, mature HGF emerged in the liver 6 hours following anti-Fas injection, and hepatic PCNA-labeling index started to increase following 24 hours and peaked at 48 hours. In the uPA(-/-) mice, emergence of mature HGF was delayed 12 hours and hepatic regeneration peaked at 96 hours. Supplementation with the uPA gene to the uPA(-/-) mice by in vivo lipofection restored hepatic plasmin levels, and improved a delay in the expression of both mature HGF and phosphorylated c-Met, accompanying a normal rate of liver regeneration. In contrast, PAI-1(-/-) mice showed accelerated liver regeneration; mature HGF emerged as early as 3 hours, and PCNA-labeling index increased at 24 hours. This accelerated regeneration was abolished by administration with anti-HGF antibody. These results strongly suggest a physiologic role of uPA in the proteolytic maturation of HGF, and thereby in hepatic regeneration after Fas-mediated massive hepatocyte death.

Gastric T-cell lymphoma presenting with epithelioid granulomas mimicking tuberculosis in regional lymph nodes

In patients with malignant lymphomas, a sarcoid reaction is occasionally observed. However, lymphoma-related granulomas with caseous necrosis are rare. We describe such a case of T-cell gastric lymphoma that was difficult to diagnose. A 50-year-old man was referred to our hospital because of abnormal gastric endoscopic findings: hypertrophic folds with narrowing of the gastric lumen and multiple ulcers in the body. Gastric biopsy specimens showed non-specific inflammation. An open biopsy of the enlarged gastric regional lymph nodes was performed. The sections revealed effacement of the normal architecture and replacement by numerous epithelioid granulomas accompanied by Langhan's type giant cells with or without central caseous necrosis, strongly suggesting tuberculosis. However, mycobacteria and other causative organisms were not detected, and an anti-tuberculous regimen was ineffective. Repeat gastric biopsies were performed and, finally, atypical lymphocytes were observed infiltrating the mucosa. The patient was diagnosed with gastric T-cell lymphoma based on the results of immunohistochemical stainings. After chemotherapy, a total gastrectomy was performed. The diagnosis of gastric T-cell lymphoma with a sarcoid reaction was confirmed by histological findings of the sections. Namely, the gastric wall was replaced by atypical lymphocytes showing the phenotype of helper T cells, admixed with epithelioid granulomas with Langhan's type giant cells. Thus, this case suggests that regional lymph nodes in gastric lymphomas may be present as epithelioid granulomas with caseous necrosis, mimicking tuberculosis.