Bombyx mori epidermal growth factor receptor is required for nucleopolyhedrovirus replication

Baculovirus-host interactions are important models for studying the biological control of lepidopteran pests. Research on baculovirus-host interactions has focussed on baculovirus manipulation of cellular signalling pathways, including the extracellular signal-regulated kinase (ERK) and phosphatidylinositol-3-kinases/protein kinase B (PI3K/Akt) signalling pathways. However, the mechanism underlying ERK and PI3K/Akt activation and function in response to baculovirus infection remains poorly understood. Here, we demonstrated that baculovirus activated the Bombyx mori ERK and PI3K/Akt signalling pathways via the B. mori epidermal growth factor receptor (BmEGFR). To further characterize the function of the BmEGFR/ERK signalling pathway in baculovirus replication, we calculated genome-wide changes in kinase-chromatin interactions for ERK after baculovirus infection using chromatin immunoprecipitation followed by high-throughput sequencing. A Gene Ontology analysis showed that virus infection had effects on the biological regulation, cellular process and metabolic process pathways. Moreover, ERK was shown to regulate the transcription of late viral genes. Taken together, our results suggest that baculoviruses manipulate components of the host cell machinery for replication via modulation of the BmEGFR signalling pathway.

Chemokine (C-X-C motif) ligand 1 is a myokine induced by palmitate and is required for myogenesis in mouse satellite cells

AIM

The functional significance of the myokines, cytokines and peptides produced and released by muscle cells has not been fully elucidated. The purpose of this study was to identify a myokine with increased secretion levels in muscle cells due to saturated fatty acids and to examine the role of the identified myokine in the regulation of myogenesis.

METHODS

Human primary myotubes and mouse C2C12 myotubes were used to identify the myokine; its secretion was stimulated by palmitate loading. The role of the identified myokine in the regulation of the activation, proliferation, differentiation and self-renewal was examined in mouse satellite cells (skeletal muscle stem cells).

RESULTS

Palmitate loading promoted the secretion of chemokine (C-X-C motif) ligand 1 (CXCL1) in human primary myotubes, and it also increased CXCL1 gene expression level in C2C12 myotubes in a dose- and time-dependent manner. Palmitate loading increased the production of reactive oxygen species along with the activation of nuclear factor-kappa B (NF-κB) signalling. Pharmacological inhibition of NF-κB signalling attenuated the increase in CXCL1 gene expression induced by palmitate and hydrogen peroxide. Palmitate loading significantly increased CXC receptor 2 gene expression in undifferentiated cells. CXCL1 knockdown attenuated proliferation and myotube formation by satellite cells, with reduced self-renewal. CXCL1 knockdown also significantly decreased the Notch intracellular domain protein level.

CONCLUSION

These results suggest that secretion of the myokine CXCL1 is stimulated by saturated fatty acids and that CXCL1 promotes myogenesis from satellite cells to maintain skeletal muscle homeostasis.

Characterization and evolutionary analysis of tributyltin-binding protein and pufferfish saxitoxin and tetrodotoxin-binding protein genes in toxic and nontoxic pufferfishes

Understanding the evolutionary mechanisms of toxin accumulation in pufferfishes has been long-standing problem in toxicology and evolutionary biology. Pufferfish saxitoxin and tetrodotoxin-binding protein (PSTBP) is involved in the transport and accumulation of tetrodotoxin and is one of the most intriguing proteins related to the toxicity of pufferfishes. PSTBPs are fusion proteins consisting of two tandem repeated tributyltin-binding protein type 2 (TBT-bp2) domains. In this study, we examined the evolutionary dynamics of TBT-bp2 and PSTBP genes to understand the evolution of toxin accumulation in pufferfishes. Database searches and/or PCR-based cDNA cloning in nine pufferfish species (6 toxic and 3 nontoxic) revealed that all species possessed one or more TBT-bp2 genes, but PSTBP genes were found only in 5 toxic species belonging to genus Takifugu. These toxic Takifugu species possessed two or three copies of PSTBP genes. Phylogenetic analysis of TBT-bp2 and PSTBP genes suggested that PSTBPs evolved in the common ancestor of Takifugu species by repeated duplications and fusions of TBT-bp2 genes. In addition, a detailed comparison of Takifugu TBT-bp2 and PSTBP gene sequences detected a signature of positive selection under the pressure of gene conversion. The complicated evolutionary dynamics of TBT-bp2 and PSTBP genes may reflect the diversity of toxicity in pufferfishes.

Leptin improves fatty liver independently of insulin sensitization and appetite suppression in hepatocyte-specific Pten-deficient mice with insulin hypersensitivity

Nonalcoholic fatty liver disease (NAFLD) is recognized as the hepatic component of the metabolic syndrome. Although NAFLD is a major cause of cirrhosis and cancer of the liver of unknown cause, no established pharmacological treatment for NAFLD has been established yet. It has been reported that leptin treatment improved fatty liver dramatically as well as insulin resistance and hyperphagia in patients with lipodystrophy. However, it is unclear whether leptin improves fatty liver independently of these metabolic improvements. We investigated the liver effect of leptin independently of insulin sensitization and appetite suppression using hepatocyte-specific Pten-deficient (AlbCrePtenff) mouse, a model of severe fatty liver with insulin hypersensitivity. Male AlbCrePtenff mice were infused subcutaneously with leptin (20 ng/g/h) for 2 weeks using osmotic minipumps. Leptin infusion effectively reduced liver weight, liver triglyceride content, and glutamate pyruvate transaminase (GPT) concentrations as well as food intake and body weight without the change of plasma insulin concentration in AlbCrePtenff mice. Pair-feeding also reduced body weight but not liver triglyceride content. Pair feeding reduced α1 and α2 AMP-activated protein kinase (AMPK) activities and PGC1α gene expression in the liver, while leptin infusion unchanged them. The present study clearly demonstrated that leptin improve fatty liver independently of insulin sensitization and suppression of food intake. It was suggested that leptin improves fatty liver by stimulation of β-oxidation in the liver. The present study might provide a further understanding on the mechanism of metabolic effect of leptin.

Middle region of FancM interacts with Mhf and Rmi1 in silkworms, a species lacking the Fanconi anaemia (FA) core complex

The Fanconi anaemia (FA) pathway is responsible for interstrand crosslink (ICL) repair. Among the FA core complex components, FANCM is believed to act as a damage sensor for the ICL-blocked replication fork and also as a molecular platform for FA core complex assembly and interaction with Bloom's syndrome (BS) complex that is thought to play an important role in the processing of DNA structures such as stalled replication forks. In the present study, we found that in silkworms, Bombyx mori, a species lacking the major FA core complex components (FANCA, B, C, E, F, and G), FancM is required for FancD2 monoubiquitination and cell proliferation in the presence of mitomycin C (MMC). Silkworm FancM (BmFancM) was phosphorylated in the middle regions, and the modification was associated with its subcellular localization. In addition, BmFancM interacted with Mhf1, a histone-fold protein, and Rmi1, a subunit of the BS complex, in the different regions. The interaction region containing at least these two protein-binding domains played an essential role in FancM-dependent resistance to MMC. Our results suggest that BmFancM also acts as a platform for recruitment of both the FA protein and the BS protein, although the silkworm genome seems to lose FAAP24, a FancM-binding partner protein in mammals.

A MC motif in silkworm Argonaute 1 is indispensible for translation repression

Small RNA-mediated gene silencing is a fundamental gene regulatory mechanism, which is conserved in many organisms. Argonaute (Ago) family proteins in the RNA-induced silencing complex (RISC) play crucial roles in RNA interference (RNAi) pathways. In the silkworm Bombyx mori, four Ago proteins have been identified, named as Ago1, Ago2, Ago3 and Siwi. Ago2 participates in double-stranded RNA (dsRNA)-induced RNAi, whereas Ago3 and Siwi are involved in the Piwi-interacting RNA (piRNA) pathway. However, there is no experimental evidence concerning silkworm Ago1 (BmAgo1) in the RNAi mechanism. In the present study, we analysed the function of BmAgo1 in the microRNA (miRNA)-mediated RNAi pathway using tethering and miRNA sensor reporter assays. These results clearly demonstrate that BmAgo1 plays an indispensable role in translation repression in silkworm. Moreover, coimmunoprecipitation data indicated that BmAgo1 interacts with BmDcp2, an orthologue of mRNA-decapping enzyme 2 (Dcp2) protein in the Drosophila processing-bodies (P-bodies). Substitutions of two conserved phenylalanines (F522 and F557) by valines in the MC motif strongly impaired the function of BmAgo1 in translation repression and its localization in P-bodies, suggesting that these two amino acid residues in the MC motif of BmAgo1 are prerequisites for mRNA translation repression in B. mori.

Impairment of fear-conditioning responses and changes of brain neurotrophic factors in diet-induced obese mice

Recent epidemiological studies demonstrate that obesity is related to a high incidence of cognitive impairment. In the present study, cognitive behaviours in diet-induced obese (DIO) mice fed 60% high-fat diet for 16 weeks were compared with those in mice fed a control diet (CD) in fear-conditioning tests including both contextual and cued elements that preferentially depend on the hippocampus and amygdala, respectively. Furthermore, brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3) content in the brain areas was examined in both CD and DIO mice. In fear-conditioning tests, the freezing percentages of both contextual fear and cued fear responses in DIO mice were significantly lower than in CD mice. BDNF content in the cerebral cortex and hippocampus of DIO mice was significantly lower than that in CD mice. Its receptor, full-length TrkB, in the amygdala of DIO mice was significantly decreased compared to that in CD mice, although not in the cerebral cortex, hippocampus and hypothalamus. By contrast, NT-3 content in the hippocampus, amygdala and hypothalamus of DIO mice was significantly higher than that in CD mice. Its receptor, full-length TrkC, was not significantly different between CD and DIO mice. The present study demonstrates that DIO mice show impairment of both hippocampus-dependent contextual and amygdala-dependent cued responses in the fear-conditioning tests, as well as an imbalance in the interaction between the BDNF and NT-3 systems in the cerebral cortex, hippocampus and amygdala related to cognition and fear.

Dynamic changes in the dural sac cross-sectional area on axial loaded MR imaging: is there a difference between degenerative spondylolisthesis and spinal stenosis?

BACKGROUND AND PURPOSE

Axial loaded MR imaging, which can simulate the spinal canal of patients in a standing position, demonstrates a significant reduction of the DCSA compared with conventional MR imaging and provides valuable imaging findings in the assessment of the lumbar spinal canal. The purpose of this study was to compare the DCSA on axial loaded MR imaging between patients with DS and SpS.

MATERIALS AND METHODS

Eighty-eight consecutive patients were divided into DS and SpS groups. DCSA on conventional MR imaging and axial loaded MR imaging and changes in the DCSA induced by axial loading were compared between DS and SpS groups. The prevalence of a significant change (>15 mm(2)) in the DCSA was compared between the 2 groups.

RESULTS

Axial loaded MR imaging demonstrated significantly smaller DCSA in the DS group (35 ± 22 mm(2)) than in the SpS group (50 ± 31 mm(2)), though conventional MR imaging did not show any differences between the 2 groups. The change in the DCSA induced by axial loading was significantly larger in the DS group (17 ± 12 mm(2)) compared with the SpS group (8 ± 8 mm(2)). The prevalence of a >15-mm(2) change in the DCSA was significantly higher in the DS group (62.5%) than in the SpS group (16.7%) (odds ratio, 8.33; 95% confidence interval, 3.09-22.50).

CONCLUSIONS

Axial loaded MR imaging demonstrated significantly larger changes in the DCSA in patients with DS compared those with SpS. A significant change in the DCSA was more frequently observed in patients with DS. Axial loaded MR imaging may therefore be a more useful tool to decrease the risk of underestimating the spinal canal narrowing in patients with DS than in those with SpS.

Irbesartan treatment up-regulates hepatic expression of PPARalpha and its target genes in obese Koletsky (fa(k)/fa(k)) rats: a link to amelioration of hypertriglyceridaemia

BACKGROUND AND PURPOSE

Hypertriglyceridaemia is associated with an increased risk of cardiovascular disease. Irbesartan, a well-established angiotensin II type 1 receptor (AT(1)) blocker, improves hypertriglyceridaemia in rodents and humans but the underlying mechanism of action is unclear.

EXPERIMENTAL APPROACH

Male obese Koletsky (fa(k)/fa(k)) rats, which exhibit spontaneous hypertension and metabolic abnormalities, received irbesartan (40 mg x kg(-1) x day(-1)) or vehicle by oral gavage over 7 weeks. Adipocyte-derived hormones in plasma were measured by ELISA. Gene expression in liver and other tissues was assessed by real-time PCR and Western immunoblotting.

KEY RESULTS

In Koletsky (fa(k)/fa(k)) rats irbesartan lowered plasma concentrations of triglycerides and non-esterified fatty acids, and decreased plasma insulin concentrations and the homeostasis model assessment of insulin resistance index. However, this treatment did not affect food intake, body weight, epididymal white adipose tissue weight, adipocyte size and plasma leptin concentrations, although plasma adiponectin was decreased. Irbesartan up-regulated hepatic expression of mRNAs corresponding to peroxisome proliferator-activated receptor (PPAR)alpha and its target genes (carnitine palmitoyltransferase-1a, acyl-CoA oxidase and fatty acid translocase/CD36) that mediate hepatic fatty acid uptake and oxidation; the increase in hepatic PPARalpha expression was confirmed at the protein level. In contrast, irbesartan did not affect expression of adipose PPARgamma and its downstream genes or hepatic genes that mediate fatty acid synthesis.

CONCLUSIONS AND IMPLICATIONS

These findings demonstrate that irbesartan treatment up-regulates PPARalpha and several target genes in liver of obese spontaneously hypertensive Koletsky (fa(k)/fa(k)) rats and offers a novel insight into the lipid-lowering mechanism of irbesartan.

Angiotensin II type 1 receptor-independent beneficial effects of telmisartan on dietary-induced obesity, insulin resistance and fatty liver in mice

AIMS/HYPOTHESIS

Evidence suggests that telmisartan, an angiotensin II type 1 receptor (AT1) blocker and peroxisome proliferator-activated receptor-gamma partial agonist, has beneficial actions that limit development of the metabolic syndrome and diabetes. However, the role played by AT1 inhibition in metabolic effects elicited by telmisartan remains uncertain. Here we isolated the metabolic effects of telmisartan from AT1 antagonism.

METHODS

Male At1a (also known as Agtr1a)-deficient mice were fed a standard diet or 60% high-fat diet; those on high-fat diet were co-administered telmisartan (3 mg kg(-1) day(-1) by oral gavage) or vehicle for 12 weeks.

RESULTS

In At1a-null mice, telmisartan prevented high-fat-diet-induced increases in (1) body weight, epididymal and inguinal white adipose tissue weight, adipocyte size and plasma leptin concentration; (2) plasma glucose and insulin concentrations and HOMA index; and (3) liver weight and triacylglycerol content. Insulin tolerance testing also indicated that telmisartan improved the high-fat-diet-induced reduction of glucose-lowering by insulin.

CONCLUSIONS/INTERPRETATION

The present findings demonstrate beneficial, AT1-independent effects of the AT1 blocker telmisartan on dietary-induced obesity, insulin resistance and fatty liver in animals.

Feasibility and efficiency of indirect lifestyle interventions in offspring of type 2 diabetic patients

INTRODUCTION

Individuals genetically predisposed to type 2 diabetes represent an important target for preventive strategies. Genetic screening, based on information about individual genetic variants, will be possible technically, but translational research in this field is still insufficient. Family history thus represents a useful tool for detecting genetically high-risk populations in this post-genomic era.

OBJECTIVES

The purpose of this pilot study was to investigate the feasibility and efficiency of indirect lifestyle interventions in offspring of type 2 diabetic patients.

METHODS

Offspring were recruited from 74 diabetic (Group 1) and 39 non-diabetic (Group 2, control group) patients. A lifestyle intervention was conducted by mail, a total of 3 times, every 3 months. Lifestyle related to diet and physical activity was assessed using a self-administered questionnaire.

RESULTS

Ten offspring of type 2 diabetic and 6 of non-diabetic patients participated in this study. Total energy intake decreased after 3 interventions in both of the groups (Group 1: 305 ± 228.8 kcal/day, p = 0.004; Group 2: 82 ± 65.6 kcal/day, p = 0.04); however, the effect of intervention was significantly greater in Group 1 compared to Group 2 (p = 0.021). Physical activity and other physical outcomes were stable in normal levels during the study period in both of the groups.

CONCLUSIONS

The intervention program helped to reduce total energy intake in offspring of type 2 diabetic patients more than in the control group, but the acceptance rate of the intervention program was disappointingly low. Further consideration is required to access and motivate offspring to develop precautionary lifestyle principles.

An adipose tissue-independent insulin-sensitizing action of telmisartan: a study in lipodystrophic mice

Adipose tissue plays an important role in energy balance and metabolism and is the major target for insulin-sensitizing peroxisome proliferator-activated receptor (PPAR) gamma agonists. The angiotensin II type 1 receptor blocker telmisartan, a partial agonist of PPAR-gamma, has been demonstrated to improve insulin sensitivity. However, there is uncertainty about the sites of its action. Here, we demonstrate that treatment with telmisartan (3 mg/kg p.o.) for 7 weeks decreased plasma glucose levels in oral glucose and insulin tolerance tests and the index of the homeostasis model assessment of insulin resistance in A-ZIP/F-1 transgenic mice, an animal model of lipodystrophy. These effects were accompanied by decreases in circulating triglyceride and fatty acid levels. However, this treatment did not affect body weight and plasma adiponectin, leptin, and corticosterone levels. In A-ZIP/F-1 mouse liver the transcripts encoding PPAR-gamma and its downstream lipogenic genes were highly up-regulated, consistent with increased hepatic triglyceride content and lipid droplet accumulation. Telmisartan reversed these effects and also down-regulated mRNAs encoding gluconeogenic genes. Thus, the present findings are consistent with a novel mode of insulin-sensitizing action of telmisartan, involving an adipose tissue-independent pathway. Telmisartan-elicited down-regulation of hepatic expression of PPAR-gamma-regulated lipogenic genes is associated with amelioration of fatty liver.

Overexpression of E2F-5 correlates with a pathological basal phenotype and a worse clinical outcome

The purpose of the present study is to identify genes that contribute to cell proliferation or differentiation of breast cancers independent of signalling through the oestrogen receptor (ER) or human epidermal growth factor receptor 2 (HER2). An oligonucleotide microarray assayed 40 tumour samples from ER(+)/HER2(−), ER(+)/HER2(+), ER(−)/HER2(+), and ER(−)/HER2(−) breast cancer tissues. Quantitative reverse transcriptase PCR detected overexpression of a cell cycle-related transcription factor, E2F-5, in ER-negative breast cancers, and fluorescence in situ hybridisation detected gene amplification of E2F-5 in 5 out of 57 (8.8%) breast cancer samples. No point mutations were found in the DNA-binding or DNA-dimerisation domain of E2F-5. Immunohistochemically, E2F-5-positive cancers correlated with a higher Ki-67 labelling index (59.5%, P=0.001) and higher histological grades (P=0.049). E2F-5-positive cancers were found more frequently in ER(−)/progesterone receptor (PgR)(−)/HER2(−) cancer samples (51.9%, P=0.0049) and in breast cancer samples exhibiting a basal phenotype (56.0%, P=0.0012). Disease-free survival in node-negative patients with E2F-5-positive cancers was shorter than for patients with E2F-5-negative cancers. In conclusion, we identify, for the first time, a population of breast cancer cells that overexpress the cell cycle-related transcription factor, E2F-5. This E2F-5-positive breast cancer subtype was associated with an ER(−)/PgR(−)/HER2(−) status, a basal phenotype, and a worse clinical outcome.

Facet cyst haematoma in the lumbar spine: a report of four cases

We present 4 cases of facet cyst haematoma in the ligamentum flavum of the lumbar spine. All patients presented with a one-to-3-month history of back pain or numbness in the legs, and sudden neurological deterioration. One also developed cauda equina syndrome and another developed radiculopathy. In all cases, magnetic resonance imaging showed a mass with high signal intensity on both T1- and T2-weighted images. Facet arthrography and computed tomography revealed communication between the mass and the neighbouring facet joint. The haematomas were removed en bloc with the ligamentum flavum. They were surrounded by the ligament and contained degenerated and lacerated elastic fibres but no synovial lining cells. Facet cyst haematoma is so-named because of bleeding from tissue adjacent to the facet joint into a pre-existing facet cyst.

Beneficial effects of leptin on glycaemic and lipid control in a mouse model of type 2 diabetes with increased adiposity induced by streptozotocin and a high-fat diet

AIMS/HYPOTHESIS

We have previously demonstrated the therapeutic usefulness of leptin in lipoatrophic diabetes and insulin-deficient diabetes in mouse models and could also demonstrate its dramatic effects on lipoatrophic diabetes in humans. The aim of the present study was to explore the therapeutic usefulness of leptin in a mouse model of type 2 diabetes with increased adiposity.

METHODS

To generate a mouse model mimicking human type 2 diabetes with increased adiposity, we used a combination of low-dose streptozotocin (STZ, 120 microg/g body weight) and high-fat diet (HFD, 45% of energy as fat). Recombinant mouse leptin was infused chronically (20 ng [g body weight](-1) h(-1)) for 14 days using a mini-osmotic pump. The effects of leptin on food intake, body weight, metabolic variables, tissue triacylglycerol content and AMP-activated protein kinase (AMPK) activity were examined.

RESULTS

Low-dose STZ injection led to a substantial reduction of plasma insulin levels and hyperglycaemia. Subsequent HFD feeding increased adiposity and induced insulin resistance and further augmentation of hyperglycaemia. In this model mouse mimicking human type 2 diabetes (STZ/HFD), continuous leptin infusion reduced food intake and body weight and improved glucose and lipid metabolism with enhancement of insulin sensitivity. Leptin also decreased liver and skeletal muscle triacylglycerol content accompanied by an increase of alpha2 AMPK activity in skeletal muscle. Pair-feeding experiments demonstrated that leptin improved glucose and lipid metabolism independently of the food intake reduction.

CONCLUSIONS/INTERPRETATION

This study demonstrates the beneficial effects of leptin on glycaemic and lipid control in a mouse model of type 2 diabetes with increased adiposity, indicating the possible clinical usefulness of leptin as a new glucose-lowering drug in humans.

Intracellular changes of metal elements by fucoidan extracted from brown seaweed (Cladosiphon okamuranus)

This study was undertaken to elucidate the intracellular changes of metal elements after the administration of fucoidan extracted from Cladosiphon okamuranus. TRL1215 cells (normal rat liver cell line) were treated with 0, 0.1, or 1.0 mg/ml fucoidan and incubated in 5% CO2 at 37 degrees C. The cellular levels of Mg, Al, Fe, and Zn were significantly increased in the 1.0 mg/ml fucoidan-treated cells compared to those of the 0.1 mg/ml fucoidan-treated cells and the control. Next, TRL1215 cells were cultured on Mylar film overnight. At 24 h after 5-bromo-2'-deoxyuridine dosing, 0, 0.1, or 1.0 mg/ml fucoidan was treated for 9 h. The cellular distribution of elements was analyzed using in-air micro-micro-particle induced X-ray emission. The X-ray spectra showed that yields of Al, Mg, and Zn were high in order of the 1.0 mg/ml fucoidan-treated sample, the 0.1 mg/ml fucoidan-treated sample, and the control. Fe yield was mildly increased by fucoidan administration. In fucoidan-treated cells, the focal accumulation of Br was correlated spatially with phosphorous-rich region, suggesting that Br was localized within the nucleus. Al distribution provided a spatial association with Br map. These data suggest that fucoidan increases the accumulations of Al, Mg, Fe, and Zn in normal rat hepatocytes, and fucoidan-binding Al is postulated to be transferred into the nucleus.

Functions of a GnRH receptor heterodimer of the ascidian, Ciona intestinalis

Gonadotropin-releasing hormone (GnRH) is a ten-amino acid peptide hormone that plays pivotal roles in reproduction in vertebrates and octopus. Recently, six GnRH forms (t-GnRH-3-8) and four GnRH receptor subtypes (Ci-GnRHR-1-4) were identified in the protochordate, Ciona intestinalis. In this study, we show the functional modulation of Ci-GnRHR-1 via heterodimerization with the orphan receptor subtype, Ci-GnRHR-4. The dimerization between Ci-GnRHR-1 and R-4 was detected by co-immunoprecipitation and immunoblot analysis. Binding assays confirmed the binding of t-GnRHs to Ci-GnRHR-1 but not to R-4, and verified no alternation in ligand-binding affinity between Ci-GnRHR-1 homodimer and Ci-GnRHRI&4 heterodimer. The heterodimer was found to stimulate the elevation of intracellular calcium, time-extension of ERK phosphorylation, and up-regulation of cell proliferation, all in a ligand specific manner, compared with the Ci-GnRHR-1 homodimer. In combination, these results indicated that Ci-GnRHR-4 is not an inactive receptor, but a modulatory factor for Ci-GnRHR-1 in C. intestinalis.

Seasonal and spatial variations in characteristics of Lake Biwa dissolved organic matter: sorption of pyrene and its derivatives and fluorescence properties

The objectives of this research were to investigate seasonal and spatial variations in (1) sorption of pyrene and its derivatives onto dissolved organic matter (DOM) and (2) fluorescence properties of DOM in Lake Biwa, Japan. In the case of pyrene, sorption coefficient (Kdoc) of Lake Biwa DOM seasonally changed from 1,200 to 3,800 L/kgC. Vertical distribution of Kdoc was affected by thermocline formation in summer, while it was uniformly distributed as a result of vertical mixing in winter. Functional groups affected sorption of pyrene onto Lake Biwa DOM in different manner from that onto Suwannee River fulvic acid. Three-dimensional excitation emission matrices (3D-EEMs) fluorescence spectroscopy was applied to characterize Lake Biwa DOMs and indicated the existence of at least two fluorophores. The two major peaks at Ex230/Em300 and Ex230/Em425 originated from protein-like and fulvic/humic-like substances, respectively. The peak at Ex230/Em300 showed the maximum fluorescence intensity at a depth of 5 m and could be affected by stratification of the water column in summer. On the other hand, the peak at Ex230/Em425 showed similar profiles both in summer and in winter. These results demonstrably showed that sorption of micropollutants and fluorescence properties of Lake Biwa DOMs were seasonally and spatially varied.

Ceramide and adenosine 5'-monophosphate-activated protein kinase are two novel regulators of 11beta-hydroxysteroid dehydrogenase type 1 expression and activity in cultured preadipocytes

Increased activity of intracellular glucocorticoid reactivating enzyme, 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) in obese adipose tissue contributes to adipose dysfunction. As recent studies have highlighted a potential role of preadipocytes in adipose dysfunction, we tested the hypothesis that a variety of metabolic stress mediated by ceramide or AMP-activated protein kinase (AMPK) would regulate 11beta-HSD1 in preadipocytes. The present study is the first to show that 1) expression of 11beta-HSD1 in 3T3-L1 preadipocytes was robustly induced when cells were treated with cell-permeable ceramide analogue C(2) ceramide, bacterial sphingomyelinase, and sphingosine 1-phosphate, 2) 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR)-induced activation of AMPK augmented the expression and enzyme activity of 11beta-HSD1, and 3) these results were reproduced in human preadipocytes. We demonstrate for the first time that C(2) ceramide and AICAR markedly induced the expression of CCAAT/enhancer-binding protein (C/EBP) beta and its binding to 11beta-HSD1 promoter. Transient knockdown of C/EBPbeta protein by small interfering RNA markedly attenuated the expression of 11beta-HSD1 induced by C(2) ceramide or AICAR. The present study provides novel evidence that ceramide- and AMPK-mediated signaling pathways augment the expression and activity of 11beta-HSD1 in preadipocytes by way of C/EBPbeta, thereby highlighting a novel, metabolic stress-related regulation of 11beta-HSD1 in a cell-specific manner.

The secretory leukocyte protease inhibitor (SLPI) suppresses cancer cell invasion but promotes blood-borne metastasis via an invasion-independent pathway

An invasion-independent pathway has been proposed as a novel mechanism in blood-borne metastasis, where tumour cells enveloped by sinusoidal tumour vessels enter the circulation without vascular invasion. We previously identified the secretory leukocyte protease inhibitor (SLPI) as a candidate gene responsible for this pathway. In this study, the functional role of SLPI in metastatic dissemination was investigated. We transfected the SLPI gene into a poorly metastatic clone of the MCH66 mouse mammary tumour cell line. Over-expression of SLPI promoted in vivo growth and spontaneous metastasis to the lung, whereas it suppressed invasive activity in vitro. The inoculated tumours of SLPI-transfectants exclusively induced a sinusoidal vasculature and subsequently produced endothelial-coated tumour emboli, which are morphological indices of the invasion-independent pathway. In addition, exogenous SLPI inhibited the migration activity through Matrigel of both tumour cells and human umbilical vein endothelial cells (HUVECs). In vivo angiogenesis assays also demonstrated that SLPI suppressed the migration of newly formed blood vessels. These results suggest that an anti-migratory effect of SLPI on tumour-associated endothelial cells may induce vascular remodelling to form a sinusoidal architecture, and consequently promote invasion-independent metastasis. This study provides a new model for metastasis, based on the mechanism regulated by anti-invasive factors, such as SLPI.

Analysis of tissue cadmium distribution in chronic cadmium-exposed mice using in-air micro-PIXE

This study undertook the analysis of tissue cadmium (Cd) distribution using in-air micro-particle-induced X-ray emission (PIXE) and the examination of the involvement of metal ions in parenteral Cd toxicity. A mouse was injected intraperitoneally with 3 mg/kg body weight of CdCl2 thrice weekly. After 27 wk, the liver and kidney were excised and fixed in 10% formalin solution for 4 h and then embedded in paraffin. Thin paraffin sections were used to analyze trace elements with in-air micro-PIXE and to examine metallothionein protein and histological changes. Cd distribution was determined by micro-PIXE in the liver and renal cortex of the Cd-exposed mouse, and the net Cd count was higher in the liver than in the renal cortex. The net iron (Fe) count was higher in the liver of the Cd-exposed mouse compared to the control, and an opposite tendency was observed in the renal cortex. Wide cellular Cd distribution was demonstrated in the liver and renal cortex of the chronic Cd-exposed mouse compared to the control. Metallothionein staining was increased by chronic exposure to Cd both in the liver and kidney, and nephrotoxicity was more apparent than hepatotoxicity. The modification of tissue Fe and calcium distribution by an intraperitoneal injection of Cd might be involved in Cd-induced toxicity.

Chronic hypoxia alters calbindin D-28k immunoreactivity in lingual and laryngeal taste buds in the rat

The distribution and abundance of the calcium binding protein, calbindin D-28k (CB) immunoreactivity in the taste buds of the circumvallate papillae and larynx were compared between normoxic and chronically hypoxic rats (10% O2 for 8 weeks). In the normoxic rats, CB immunoreactivity was observed in some cells and fibers of the intragemmal region of the taste buds in the circumvallate papillae. In contrast, in the subgemmal region of the laryngeal taste buds, fibers but not cells were immunoreactive for CB. In chronically hypoxic rats, CB immunoreactive cells and fibers in the taste buds were decreased in the circumvallate papillae. In the laryngeal taste buds, the density of the subgemmal CB immunoreactive fibers in chronically hypoxic rats was greater than in normoxic rats. It is considered that function of the laryngeal taste buds is different from that of the lingual taste buds, so that laryngeal taste buds may be involved in chemosensation other than taste. The altered density of CB immunoreactive cells and fibers in the lingual and laryngeal taste buds is a predominant feature of hypoxic adaptation, and chronic hypoxic exposure might change the chemical sensitivity of the circumvallate papillae and larynx through the regulation of intracellular Ca2+.

Benign Pleomorphic Astrocytoma in the Hypothalamus-Case Report-

A 41-year-old woman presented with an unusual case of benign astrocytoma with marked pleomorphism manifesting as consciousness disturbance due to intraventricular hemorrhage. Magnetic resonance imaging revealed a well-enhanced hypothalamic mass protruding into the third ventricle. Despite partial resection of the tumor without additional therapy, there have been no signs of tumor regrowth for 6 years. The histological findings revealed solid proliferation of tumor cells with marked pleomorphism, contrary to the benign clinical course. However, no mitosis, necrosis, or endothelial proliferation were found and the MIB-1 index was less than 0.5%. Immunohistochemical staining indicated the glial origin of the tumor. The tumor was similar to pleomorphic xanthoastrocytoma, but the histological findings were not exactly identical, indicating a new histological entity.

Hypoxic adaptation of the rat carotid body

Three types of hypoxia with different levels of carbon dioxide (hypocapnic, isocapnic, and hypercapnic hypoxia) have been called systemic hypoxia. The systemic hypoxic carotid bodies were enlarged several fold, but the degree of enlargement was different for each. The mean short and long axes of hypocapnic and isocapnic hypoxic carotid bodies were 1.6 (short axis) and 1.8-1.9 (long axis) times larger than normoxic control carotid bodies, respectively. Those of hypercapnic hypoxic carotid bodies were 1.2 (short axis) and 1.5 (long axis) times larger than controls, respectively. The rate of enlargement in hypercapnic hypoxic carotid bodies was lower than in hypocapnic and isocapnic hypoxic carotid bodies. The rate of vascular enlargement in hypercapnic hypoxic carotid bodies was also smaller than in hypocapnic and isocapnic hypoxic carotid bodies. Thus, the enlargement of hypoxic carotid bodies is mainly due to vascular dilation. Different levels of arterial CO2 tension change the peptidergic innervation during chronically hypoxic exposure. The characteristic vascular arrangement was under the control of altered peptidergic innervation. During the course of hypoxic adaptation, the enlargement of the carotid bodies with vascular expansion began soon after the start of hypoxic exposure. During the course of recovery, the shrinking of the carotid bodies with vascular contraction also started at a relatively early period after the termination of chronic hypoxia. These processes during the course of hypoxic adaptation and during the course of recovery were under the control of peptidergic innervation. These findings may provide a standard for further studies of hypoxic carotid bodies.

Differential expression of a Bombyx mori AHA1 homologue during spermatogenesis

The AHA1 (activator of Hsp90 ATPase) family of proteins were exclusively conserved from yeast to humans, but little is known about their tissue distribution or biological function. In this study, a cDNA for a Bombyx mori AHA1 homologue, BmAHA1, was isolated from the testes of larvae on day 3 of the fifth instar using an mRNA differential display method. This cDNA encodes a protein with 341 amino acid residues. Gene expression studies revealed that BmAHA1 mRNA occurred prominently in the testes. In situ hybridization and immunostaining showed that the BmAHA1 mRNA signals were strongly detected in spermatogonial cells and primary spermatocytes at the fifth larval instar stage, whereas the BmAha1 protein was abundant in round and elongated spermatids at the pupal stage. The localization pattern of the accumulated protein in the elongated spermatids was reminiscent of that reported previously for microtubules, but the BmAha1 protein showed a decrease in apparent concentration during maturation process. The stage- and cell-specific expression indicated that BmAha1 might play a role in silkworm spermatogenesis, especially in postmeiotic differentiation.

Morphological changes in the rat carotid body 1, 2, 4, and 8 weeks after the termination of chronically hypocapnic hypoxia

Morphological changes in the rat carotid bodies 1, 2, 4, and 8 weeks after the termination of chronically hypocapnic hypoxia (10% O2 for 8 weeks) were examined by means of morphometry and immunohistochemistry. The rat carotid bodies after 8 weeks of hypoxic exposure were enlarged several fold with vascular expansion. The carotid bodies 1 and 2 weeks after the termination of 8 weeks of hypoxic exposure were diminished in size, although their diameter remained larger than the normoxic controls. The expanded vasculature in chronically hypoxic carotid bodies returned to the normoxic control state. In the carotid bodies 1 week after the termination of chronic hypoxia, the density of NPY fibers was remarkably increased and that of VIP fibers was dramatically decreased in comparison with the density in chronically hypoxic carotid bodies. In the carotid bodies 2 and 4 weeks after the termination of hypoxia, the density of SP and CGRP fibers was gradually increased. In the carotid bodies 8 weeks after the termination of hypoxia, the appearance of the carotid body returned to a nearly normoxic state, and the density of SP, CGRP, VIP, and NPY fibers also recovered to that of normoxic controls. These results suggest that the morphological changes in the recovering carotid bodies start at a relatively early period after the termination of chronic hypoxia, and a part of these processes may be under the control of peptidergic innervation.

Peptidergic innervation in the rat carotid body after 2, 4, and 8 weeks of hypocapnic hypoxic exposure

The distribution and abundance of neuropeptide-containing nerve fibers were examined in the carotid bodies of rats exposed to hypocapnic hypoxia (10% O2 in N2) for 2, 4, and 8 weeks. The carotid bodies after 2, 4, and 8 weeks of hypoxic exposure were enlarged by 1.2-1.5 times in the short axis, and 1.3-1.7 times in the long axis in comparison with the normoxic control ones. The enlarged carotid bodies contained a number of expanded blood vessels. Mean density per unit area (10(4) microm2) of substance P (SP) and calcitonin gene-related peptide (CGRP) immunoreactive fibers was transiently high in the carotid bodies after 4 weeks of hypoxic exposure, and decreased significantly to nearly or under 50% after 8 weeks of hypoxic exposure. Density of vasoactive intestinal polypeptide (VIP) immunoreactive fibers increased significantly in all periods of hypoxic exposure observed, and was especially high in the carotid bodies after 4 weeks of hypoxic exposure. Density of neuropeptide Y immunoreactive fibers was unchanged in the carotid bodies during hypoxic exposure. These characteristic changes in the density of SP, CGRP, and VIP fibers in the carotid bodies after 4 weeks of hypoxic exposure suggest that the role of these neuropeptide-containing fibers may be different in the carotid bodies after each of three periods of hypoxic exposure, and that the peptidergic innervation after 8 weeks of hypoxic exposure may show an acclimatizing state.

Overexpression of fatty acid synthase in oesophageal squamous cell dysplasia and carcinoma

OBJECTIVE

The expression of fatty acid synthase (FAS), an enzyme necessary for de novo fatty acid synthesis, has been examined in several types of tumours so far, but not in oesophageal cancer and dysplasia.

METHODS

We examined the immunohistochemical reactivity of FAS in 4 normal adult oesophagi, 14 dysplastic oesophageal lesions, and 80 squamous cell carcinomas and 6 cases with 4 special types of malignancies of the oesophagus. We also analysed the correlation between FAS expression and various clinicopathological features and long-term survival in patients with oesophageal cancer.

RESULTS

In the normal oesophagus, only faint cytoplasmic FAS expression was observed in cells of the basal layer. In contrast, FAS-positive cells were found in 92.9% of cases of dysplasia and 96.5% of cases of carcinoma including 6 cases with a specific histological subtype. However, high expression of FAS did not correlate with either clinicopathological features or prognosis of patients with oesophageal cancer.

CONCLUSION

Our results demonstrate that FAS is expressed in almost all oesophageal carcinomas of both usual and special types and dysplastic lesions, suggesting that FAS may be upregulated continuously from the early stage of oesophageal squamous cell carcinogenesis to established carcinoma.

Second-generation intramedullary supracondylar nail for distal femoral fractures

The objective of this study was to review the use of intramedullary supracondylar (IMSC) nails for distal femoral fractures. We reviewed 24 fractures treated with second-generation IMSC nails. The fractures consisted of 18 type A1, one type A2, two type C1, one type C2, and two type C3 fractures. The relationships between clinical results and fracture type, approaches, and patient age were retrospectively reviewed. All fractures healed clinically and radiographically. Twenty-one patients maintained gait performance equivalent to that before injury. Average operating time was 108 min +/- 43 min. ROM in the knee of all patients was -5 degrees +/- 6 degrees in extension and 102 degrees +/- 38 degrees in flexion. Extension lag was influenced by surgical approach. The final knee arc was inversely correlated to patient age (R: 0.49, P<0.05). There were three varus/valgus deformities, two cases with loosening, and two with breakage of the distal locking screws, but no failure of the nail itself. Second-generation IMSC nailing for distal femur fractures was satisfactory in patients younger than 60 years of age.

Fatty acid synthase is highly expressed in carcinoma, adenoma and in regenerative epithelium and intestinal metaplasia of the stomach

AIMS

To investigate the relation of fatty acid synthase (FAS) expression to the clinicopathological characteristics of gastric cancers and gastric tumorigenesis.

METHODS AND RESULTS

FAS expression was examined immunohistochemically in 626 gastric cancers, 51 gastric adenomas, and non-neoplastic epithelium contiguous with cancer tissue including normal foveolae, intestinal metaplasia, regenerative epithelium, and gastric glands. FAS expression was found in more than 70% of gastric cancers. Interestingly, it occurred preferentially in differentiated carcinomas, male cases, and in patients over 51 years old. Although previous reports showed that FAS expression is closely related to cancer progression, in gastric cancers FAS expression had no relationship with prognosis, cancer progression as indicated by depth of invasion, venous and lymphatic permeation, and distant metastasis. Gastric tubular adenoma and intestinal metaplasia, which are thought to be associated with well-differentiated gastric carcinomas, showed a frequency of FAS expression similar to that of differentiated carcinomas; however, normal foveolae and gastric glands showed no or less FAS expression.

CONCLUSIONS

FAS expression occurs at the early stage of tumorigenesis and plays important roles in the formation of precancerous foci rather than in the progression of carcinoma of the stomach.

Changes in the peptidergic innervation in the carotid body of rats chronically exposed to hypercapnic hypoxia: an effect of arterial CO2 tension

The abundance of neuropeptide Y (NPY)-, vasoactive intestinal polypeptide (VIP)-, substance P (SP)-, and calcitonin gene-related peptide (CGRP)-immunoreactive nerve fibers in the carotid body was examined in chronically hypercapnic hypoxic rats (10% O2 and 6-7% CO2 for 3 months), and the distribution and abundance of these four peptidergic fibers were compared with those of previously reported hypocapnic- and isocapnic hypoxic carotid bodies to evaluate the effect of arterial CO2 tension. The vasculature in the carotid body of chronically hypercapnic hypoxic rats was found to be enlarged in comparison with that of normoxic control rats, but the rate of vascular enlargement was smaller than that in the previously reported hypocapnic- and isocapnic hypoxic carotid bodies. In the chronically hypercapnic hypoxic carotid body, the density per unit area of parenchymal NPY fibers was significantly increased, and that of VIP fibers was unchanged, although the density of NPY and VIP fibers in the previously reportetd chronically hypocapnic and isocapnic hypoxic carotid bodies was opposite to that in hypercapnic hypoxia as observed in this study. The density of SP and CGRP fibers was decreased. These results along with previous reports suggest that different levels of arterial CO2 tension change the peptidergic innervation in the carotid body during chronically hypoxic exposure, and altered peptidergic innervation of the chronically hypercapnic hypoxic carotid body is one feature of hypoxic adaptation.

Observation of the isomer effect on charge transfer from C3H4 molecules (allene and propyne) at keV energies

The apparent isomer effect on charge transfer processes in collisions of the ground-state C+ ions with allene and propyne, which have the same C3H4 molecular chemical notation, has been observed experimentally in the collision energy from 0.2 to 4.5 keV. The difference in total charge transfer cross sections between the two isomers was found to be 32% at 0.2 keV, although it decreases to 10% at 4.5 keV. This difference is out of experimental uncertainty of 14.6% at least below the collision energy of 0.5 keV and should be regarded as a real isomer effect. Theoretical analysis based on a molecular orbital expansion method has also confirmed the experimental finding and provided the rationale.

Identification of three annexin IX isoforms generated by alternative splicing of the carboxyl-terminal exon in silkworm, Bombyx mori

Annexins (ANXs) are a family of structurally related proteins with Ca(2+)-dependent phospholipid-binding properties. Here we report the cloning of three cDNAs each encoding annexin IX (ANX IX) isoforms from unfertilized eggs of the silkworm, Bombyx mori. The analysis of exon/intron structures showed that the three mRNAs, named ANX IX-A (2300bp), ANX IX-B (1884bp) and ANX IX-C (1409bp), respectively, were generated from a single gene by alternative usage of a 3'-splice site of the last exon. Thus the three isoforms have an identical sequence from amino acid residues 1 to 307 and this region shows approximately 77% identity to Drosophila melanogaster ANX IX. Only amino acid residues 308-324 (A) or 308-323 (B and C), which correspond to the C-terminal tail, are different in the three proteins. A RT-PCR analysis indicated that the three isoforms of silkworm ANX IX were specifically expressed in various larval tissues and development stages. Interestingly, the C-terminal tail in ANXs I, II and V were previously confirmed as a binding region for protein kinase C. Thus generation of the three ANX IX isoforms in the silkworm, that are different from other ANXs, may have a functional significance other than binding to Ca(2+).

Biological characteristics and chemosensitivity profile of four human anaplastic thyroid carcinoma cell lines

Anaplastic thyroid carcinoma is a rapidly growing, aggressive neoplasm affecting the elderly which does not respond to most of the therapies. We established cultured cell lines from four untreated tumors. The cultures grew in a monolayer of spindle-shaped cells in three cell lines and of small polygonal cells in one line, having relatively long doubling times and chromosomal abnormalities. The xenotransplantation of the lines in athymic nude mice produced tumors with a histology similar to the original tumors. The immunocytochemical staining showed the expression of PCNA, HLA-class 1, cytokeratin, vimentin and FAS (fatty acid synthase) but not CEA, desmin or P-glycoprotein. The lines secreted TPA, IL-6, IL-8 and few or no thyroid-related hormones in the culture supernatant. One cell line produced G-CSF. The chemosensitivity assay revealed intrinsic drug resistance to nine out of 11 antineoplastic agents. The reverse transcriptase-polymerase chain reaction (RT-PCR) detected MRP (multidrug resistance-associated protein) mRNA but not mdr (multidrug resistance protein)-1 and mdr-3 mRNAs. This finding indicates that the multidrug resistance of these lines is mediated by a P-glycoprotein-unrelated mechanism. The RT-PCR also presented FAS mRNA in all the lines, and IL-6 and IL-8 mRNAs in some of the lines.

Ci-opsin1, a vertebrate-type opsin gene, expressed in the larval ocellus of the ascidian Ciona intestinalis

A novel gene encoding visual pigment, Ci-opsin1, was identified in a primitive chordate, the ascidian, Ciona intestinalis. Molecular phylogenetic analysis and the exon-intron organization suggest that Ci-opsin1 is closely related to the retinal and pineal opsins of vertebrates. During embryogenesis, Ci-opsin1 transcripts were first detected in part of the brain of mid tailbud embryos; its expression was confined to photoreceptor cells of the ocellus (eye spot) in the larval brain as development proceeded. These results suggest a common descent of the ascidian ocellus and the vertebrate eyes. The ocellus of ascidian larvae may represent an ancestral state of the vertebrate eye.

Solid-phase microextraction and gas chromatography-mass spectrometry analysis of p,p' -DDE in biological samples

A simple and rapid extraction method for the analysis of p,p'-DDE from rat whole blood and tissues was developed using headspace solid-phase microextraction (SPME). A vial containing a sample of p,p'-DDE, sodium hydroxide, and benzophenone as internal standard was heated at 120 degrees C. A polydimethylsiloxane-coated SPME fiber was exposed for 15 min in the headspace of the vial. The fiber needle was then injected and desorbed by exposing the fiber in the injection port of a capillary gas chromatography-mass spectrometry system. The calibration curve demonstrated good linearity throughout the concentration range from 0.02 to 50 microg/g for rat whole blood and liver samples. The limit of detection for p,p'-DDE was 0.020 microg/g using 0.5 g rat whole blood and liver samples. Coefficients of variation ranged from 7.0 to 7.9%. This method was used to analyze a rat whole blood sample after administration of p,p'-DDE.

Linearization and integration of DNA into cells preferentially occurs at intrinsically curved regions from human LINE-1 repetitive element

A bent DNA library was constructed from human genomic DNA, from which a new clone belonging to the human LINE-1 sequence family was isolated and characterized. This clone, with a length of 378 base pairs and termed HBC-1 (human bent clone-1), contained an intrinsically occurring curved DNA structure. By permutation analysis, the center of curvature of this fragment was mapped onto the nucleotide position 886 from the 5' terminus of the complete LINE-1 sequence. Reporter plasmids, which contain HBC-1, were effectively integrated into human chromosome, indicating that the bent DNA structure provides a preferential donor site for the integration of human LINE-1 sequences. The present finding may provide an explanation as to why some inactivated LINE-1 sequences on human chromosomes carry the deletion at their 5' termini.

Expression of glucose transporter-1 in human gastric carcinoma: association with tumor aggressiveness, metastasis, and patient survival

BACKGROUND

Malignant cells show increased glucose uptake in vitro and in vivo, which is believed to be facilitated by glucose transporters (Gluts). Expression of Glut1, one of the Gluts, has been described in malignancies of the esophagus, colon, pancreas, lung, and brain, but to the authors' knowledge the significance of Glut1 expression in human gastric carcinoma has not been elucidated. The objective of the current study was to examine the expression and distribution of Glut1 and its relation to clinicopathologic parameters in patients with gastric carcinoma.

METHODS

Immunohistochemistry with anti-Glut1 antibody was performed on 617 gastric carcinomas and 50 tubular adenomas of the stomach. Glut1-positive and Glut1-negative carcinomas were analyzed for their clinicopathologic characteristics including histologic subtype, depth of invasion, vascular permeation, lymph node and hepatic metastasis, peritoneal dissemination, and prognosis.

RESULTS

None of the adenomas expressed Glut1, whereas 182 of 617 carcinomas (29.5%) were positive for the protein. Signet ring cell carcinoma and mucinous adenocarcinoma rarely were positive (2.0% and 6.3%, respectively) and papillary adenocarcinoma (44%) showed slightly higher positivity for Glut1 than tubular (32%) or poorly differentiated adenocarcinoma (28%). Glut1-positive tumor cells were localized mainly in the central part of tumor nests with or without peripheral distribution (92%) but peripheral distribution alone was very limited (8%) (P = 0.0001). Glut1 positivity was associated with depth of invasion (P = 0.0001), lymphatic permeation (P = 0.0001), venous invasion (P = 0.0001), lymph node metastasis (P = 0.0001), hepatic metastasis (P = 0.0001), and carcinoma stage (P = 0.0001). However, peritoneal dissemination was not found to be associated with Glut1 positivity (P = 0.0833). The survival of patients who had tumors that expressed Glut1 was significantly shorter than that of patients with Glut1-negative tumors (P = 0.0001).

CONCLUSIONS

In human gastric carcinoma, Glut1 is expressed late in carcinogesis and increases with disease progression. Glut1 expression is associated with tumor aggressiveness and patient survival.

Expression of glucose transporter-1 in human gastric carcinoma: association with tumor aggressiveness, metastasis, and patient survival

BACKGROUND

Malignant cells show increased glucose uptake in vitro and in vivo, which is believed to be facilitated by glucose transporters (Gluts). Expression of Glut1, one of the Gluts, has been described in malignancies of the esophagus, colon, pancreas, lung, and brain, but to the authors' knowledge the significance of Glut1 expression in human gastric carcinoma has not been elucidated. The objective of the current study was to examine the expression and distribution of Glut1 and its relation to clinicopathologic parameters in patients with gastric carcinoma.

METHODS

Immunohistochemistry with anti-Glut1 antibody was performed on 617 gastric carcinomas and 50 tubular adenomas of the stomach. Glut1-positive and Glut1-negative carcinomas were analyzed for their clinicopathologic characteristics including histologic subtype, depth of invasion, vascular permeation, lymph node and hepatic metastasis, peritoneal dissemination, and prognosis.

RESULTS

None of the adenomas expressed Glut1, whereas 182 of 617 carcinomas (29.5%) were positive for the protein. Signet ring cell carcinoma and mucinous adenocarcinoma rarely were positive (2.0% and 6.3%, respectively) and papillary adenocarcinoma (44%) showed slightly higher positivity for Glut1 than tubular (32%) or poorly differentiated adenocarcinoma (28%). Glut1-positive tumor cells were localized mainly in the central part of tumor nests with or without peripheral distribution (92%) but peripheral distribution alone was very limited (8%) (P = 0.0001). Glut1 positivity was associated with depth of invasion (P = 0.0001), lymphatic permeation (P = 0.0001), venous invasion (P = 0.0001), lymph node metastasis (P = 0.0001), hepatic metastasis (P = 0.0001), and carcinoma stage (P = 0.0001). However, peritoneal dissemination was not found to be associated with Glut1 positivity (P = 0.0833). The survival of patients who had tumors that expressed Glut1 was significantly shorter than that of patients with Glut1-negative tumors (P = 0.0001).

CONCLUSIONS

In human gastric carcinoma, Glut1 is expressed late in carcinogesis and increases with disease progression. Glut1 expression is associated with tumor aggressiveness and patient survival.

Autoradiographic studies using L-[(14)C]DOPA and L-DOPA reveal regional Na(+)-dependent uptake of the neurotransmitter candidate L-DOPA in the CNS

We previously proposed that L-3,4-dihydroxyphenylalanine (L-DOPA) is a neurotransmitter in the CNS. Receptor and transporter molecules for L-DOPA, however, have not been determined. In the present study, in order to localize the uptake sites of L-DOPA in the CNS, we performed autoradiographic uptake studies using L-[14C]DOPA and L-[3H]DOPA in the uptake study on rat brain slice preparations, and further analyzed the properties of L-DOPA uptake. Image analysis of the L-[14C]DOPA autoradiogram showed a unique heterogeneous distribution of uptake sites in the brain. The intensity was relatively high in the cerebral cortex, the hypothalamus, the cerebellum and the hippocampus, while the density was moderate or even low in the striatum and the substantia nigra. L-DOPA and phenylalanine, but not dopamine (10mM) were able to almost completely inhibit the uptake of L-[14C]DOPA to basal levels. Microautoradiographic studies using L-[3H]DOPA revealed accumulation of dense grains in the median eminence, the supraoptic nucleus of the hypothalamus, the cerebral cortex (layer I) and the hippocampus. In the cerebellum, grains formed in clusters surrounding the Purkinje cells. This grain accumulation was concluded to be in Bergmann glial cells, since the morphological pattern of grain accumulation was similar to that of the immunoreactivity of the glutamate aspartate transporter, a marker protein for Bergmann glial cells. In the hippocampus, the grain density significantly decreased under Na(+)-free conditions. In addition, grain density also decreased in the absence of Cl(-). In contrast, grains in the choroid plexus and the ependymal cell layer, were not affected by the absence of Na(+). These findings indicated that the uptake of L-DOPA occurs via various types of large neutral amino acid transport mechanisms. It appears that neuronal and/or glial cells, which take up L-DOPA in a Na(+)-dependent manner, exist in the CNS. Our finding further supports the concept that L-DOPA itself may act as a neurotransmitter or neuromodulator.

Role of interaction between two silkworm RecA homologs in homologous DNA pairing

Recombinant BmRad51 and BmDmc1, silkworm homologs of the Escherichia coli RecA proteins catalyzing the homologous DNA pairing, were purified from E. coli cells carrying expression vectors. These possessed different enzymatic properties in the joint molecule formation between single-stranded circular DNA and homologous linear double-stranded DNA. The requirement of single-stranded circular DNA for the efficient reaction was twofold higher in BmRad51 than in BmDmc1. Although able to mediate the joint molecule formation independently, a complex of the two enzymes formed prior to single-stranded DNA binding was found to have augmented efficiency of the pairing reaction.

Plasma triglyceride-rich lipoprotein remnants as a risk factor of 'Pokkuri disease'

In our recent report, it remained unclear whether or not triglyceride-rich lipoprotein remnants (RLP) were associated with the risk of sudden coronary death in younger cases without coronary atherosclerosis that were detected in about 10% of all sudden coronary death cases in Japan. These cases were categorized as 'origin unknown, but suspected to be due to coronary spasm', the so called 'pokkuri disease' in Japan. The present study population consisted of 108 sudden death cases without coronary atherosclerosis [(pokkuri disease n=57) and non-cardiac sudden death (control n=51)] aged 20-69 years from Kanagawa prefecture in Japan. All individuals had died suddenly and unexpectedly, most had no significant history of medical conditions including cardiac symptoms and had not taken medications prior to death according to their medical records. All the autopsies were performed within 12 h after death. Plasma total cholesterol (TC), triglycerides (TG), phospholipids, RLP-C and RLP-TG, VLDL-C, LDL-C, HDL-C, apolipoproteins A-I, A-II, B, C-II, C-III, E, Lp (a) and homocysteine were measured in postmortem plasma samples. The TG-rich lipoprotein remnants measured as RLP-C and RLP-TG were significantly higher in pokkuri disease compared with controls both in fasting and postprandial states (P<0.05 and P<0.001), indicating that RLP-C and RLP-TG were the most significant risk factor in pokkuri disease among the parameters tested in this study. In conclusion the TG level in RLP (RLP-TG) appeared to be strongly associated with the risk of sudden death in the absence of coronary atherosclerosis (pokkuri disease).

Occurrence of ovalbumin in ovarian yolk of chicken during oogenesis

Yolk specimens from chicken ovaries during oogenesis gave a positive signal for ovalbumin as analyzed by Western blotting, indicating that the ovarian yolk contains ovalbumin. Northern blotting and reverse transcriptase-polymerase chain reaction gave a negative signal for ovalbumin mRNA in the liver and other organs except oviduct, whereas the laying hen serum was found to indicate immunologically the presence of ovalbumin. It was therefore assumed that ovalbumin synthesized in the oviduct might partly be secreted into the blood circular system, from which it is taken up into the oocyte.