Effects of scan parameters on the accuracies of iodine quantification and hounsfield unit values in dual layer dual-energy head and neck computed tomography: A phantom study conducted in a hospital in Japan.

INTRODUCTION: No study has investigated scan parameters in head and neck dual layer dual-energy computed tomography (DL-DECT). This study aimed to select the appropriate scan parameters in head and neck imaging by evaluating the scan parameter effects on the accuracies of CT numbers and conduct iodine quantification in DL-DECT. METHODS: A multi-energy phantom was scanned using a dual layer CT (DLCT) scanner. Reference materials of iodine, blood, calcium, and adipose were used. A helical scan was performed by using reference and several protocols. Iodine density and virtual monochromatic images (VMIs) at the energy of 50, 70, and 100 keV were reconstructed. The iodine concentrations and CT numbers in each protocol were measured. Moreover, the absolute percentage errors (APEs) of iodine quantifications and CT numbers (reference vs. each protocol) were compared. Equivalence was observed when APEs between reference and each protocol was within 5%. Statistical analysis was performed using appropriate software. RESULTS: The APEs between the high-tube-voltage and reference protocol were 23.7, 14.0, 8.8, and 8.1% for iodine reference materials with concentrations equal to 2, 5, 10, and 15 mg/ml, respectively. At 50 keV, APEs between the high-tube-voltage and reference protocols were greater than 5% except for calcium and adipose. At 100 keV, APEs between the high-tube-voltage and reference protocols were greater than 5% except for blood and calcium. CONCLUSIONS: The high-tube-voltage protocol improved the accuracies of the measurement for iodine quantification and CT numbers. Additionally, the scanning parameters except for tube voltage had no effect on accuracies of iodine quantitation and CT numbers in the DLCT scanner. IMPLICATIONS FOR PRACTICE: The use of the high-tube-voltage protocol will be recommended for more accurate material decomposition in head and neck DL-DECT.

Reducing gut microbiome-driven adipose tissue inflammation alleviates metabolic syndrome.

BACKGROUND: The gut microbiota contributes to macrophage-mediated inflammation in adipose tissue with consumption of an obesogenic diet, thus driving the development of metabolic syndrome. There is a need to identify and develop interventions that abrogate this condition. The hops-derived prenylated flavonoid xanthohumol (XN) and its semi-synthetic derivative tetrahydroxanthohumol (TXN) attenuate high-fat diet-induced obesity, hepatosteatosis, and metabolic syndrome in C57Bl/6J mice. This coincides with a decrease in pro-inflammatory gene expression in the gut and adipose tissue, together with alterations in the gut microbiota and bile acid composition. RESULTS: In this study, we integrated and interrogated multi-omics data from different organs with fecal 16S rRNA sequences and systemic metabolic phenotypic data using a Transkingdom Network Analysis. By incorporating cell type information from single-cell RNA-seq data, we discovered TXN attenuates macrophage inflammatory processes in adipose tissue. TXN treatment also reduced levels of inflammation-inducing microbes, such as Oscillibacter valericigenes, that lead to adverse metabolic phenotypes. Furthermore, in vitro validation in macrophage cell lines and in vivo mouse supplementation showed addition of O. valericigenes supernatant induced the expression of metabolic macrophage signature genes that are downregulated by TXN in vivo. CONCLUSIONS: Our findings establish an important mechanism by which TXN mitigates adverse phenotypic outcomes of diet-induced obesity and metabolic syndrome. TXN primarily reduces the abundance of pro-inflammatory gut microbes that can otherwise promote macrophage-associated inflammation in white adipose tissue. Video Abstract.

Fulminant type 1 diabetes mellitus observed in insulin receptor substrate 2 deficient mice.

The objective of this study was to characterise the fulminant type 1 diabetes mellitus (DM) accompanying abrupt hyperglycaemia and ketonuria observed in insulin receptor substrate 2 (IRS2)-deficient mice. IRS2-deficient mice backcrossed onto the original C57BL/6J:Jc1 background (B6J-IRS2(-/-) mice) for more than 10 generations were used. Eight male IRS2-deficient mice with ketonuria and abrupt increase in plasma glucose concentrations over 25 mmol/l were used as the fulminant type 1 diabetic mice (diabetic mice) and 8 male IRS2-deficient mice (8 weeks old) without glycosuria were used as the control mice. Plasma metabolite, immunoreactive insulin (IRI) and C-peptide concentrations, hepatic energy metabolism related enzyme activities and histopathological change in pancreatic islets were investigated. The diabetic mice showed significantly higher plasma glucose and cholesterol concentrations and lower plasma IRI and C-peptide concentrations than the control mice. In livers of the diabetic mice, glycolytic and malate-aspartate shuttle enzyme activities decreased significantly and gluconeogenic, lipogenic and ketone body synthesis enzyme activities increased significantly compared to those in the control mice. The pancreatic islets of the diabetic mice decreased significantly in size and number of beta cells. The diabetic IRS2-deficient mice did not show the islet-related antibodies observed in the diabetic NOD mice in their sera. The characteristics of the diabetic IRS2-deficient mice resembled those of the human nonautoimmune fulminant type 1 DM. IRS2-deficient mice may be a useful animal model for studying the degradation mechanism of pancreatic beta cells in the process of development of fulminant type 1 DM.

Inhibitory effect of dietary selenium on carcinogenesis in rat glandular stomach induced by N-methyl-N'-nitro-N-nitrosoguanidine.

The influence of dietary selenium on the incidence of stomach carcinoma induced by N-methyl-N'-nitro-N-nitrosoguanidine was studied in 108 rats that survived for over 10 wk. The incidence of glandular stomach cancer in the high-selenium (4.0 ppm) diet group (20 carcinomas in 54 rats) was lower than in the low-selenium (0.1 ppm) diet group (33 carcinomas in 54 rats). The selenium level and glutathione peroxidase activity in the blood, liver, and stomach mucosa were significantly higher in the high-selenium diet group than in the low-selenium diet group. Glutathione peroxidase activity as well as the concentration of selenium in the glandular stomach was increased significantly in the high-selenium diet group.

Effect of dietary molybdenum on esophageal carcinogenesis in rats induced by N-methyl-N-benzylnitrosamine.

The influence of dietary molybdenum on esophageal carcinogenesis induced by N-methyl-N-benzylnitrosamine (2.5 mg per kg of body weight once a week for 20 wk s.c.) was studied in male F344 rats. The tumor incidence and tumor development in the esophagus were significantly lower in the rats in the high-molybdenum (2 ppm) diet group than in the rats in the low-molybdenum (0.032 ppm) diet group; i.e., 44.4% (0.6 +/- 0.8) and 73.2% (2.2 +/- 2.0), respectively. The molybdenum levels in the esophagus-forestomach, liver, and serum were significantly higher in the high-molybdenum diet group than in the low-molybdenum diet group. Xanthine oxidase activity in the esophagus and forestomach in the high-molybdenum diet group was significantly higher than that in the low-molybdenum diet group, whereas liver and serum xanthine oxidase activities were not significantly different between these two groups. These results suggest that xanthine oxidase in the esophagus plays a significant role in the inhibitory effect of molybdenum on esophageal carcinogenesis.

Effects of dietary saturated and unsaturated fatty acids on fecal bile acids and colon carcinogenesis induced by azoxymethane in rats.

To determine whether the kind of dietary fat affects colon carcinogenesis, male Donryu rats were fed a 5% fat diet containing linoleate, an unsaturated fat, or stearate, a saturated fat, in semipurified fat-free chow. The rats were given azoxymethane (7.4 mg/kg body weight) s.c. once a week for 11 weeks and killed 15 weeks after the last injection of the carcinogen. The rats on the unsaturated fat diet had a significantly higher incidence of colon tumors. Fatty acid analysis of cholesterol esters in the liver and examination of the amount of fecal bile acids showed that the unsaturated fat diet increased the level of cholesterol linoleate and arachidonate in the liver and also increased the fecal excretion of bile acids, especially that of lithocholic acid. The colon tumors in rats on the unsaturated fat diet, compared with those in rats on the saturated fat diet, contained a higher level of lysophosphatidylcholine. These results suggest that increased fecal excretion of bile acids due to increased polyunsaturated cholesterol esters in the liver stimulates phospholipase A2 activity of colon initiated cells and enhances colon carcinogenesis in rats on the unsaturated fat diet.

Effect of dietary eicosapentaenoic acid on azoxymethane-induced colon carcinogenesis in rats.

The effects of eicosapentaenoic acid (EPA, n-3 polyunsaturated fatty acid) and linoleic acid (n-6 polyunsaturated fatty acid) on azoxymethane-induced colon carcinogenesis in rats were studied. Male Donryu rats were given two types of semipurified diet containing 4.7% EPA plus 0.3% linoleic acid and 5% linoleic acid. The rats were given s.c. injection of azoxymethane (7.4 mg/kg body weight once a week for 11 weeks) and sacrificed 15 weeks after the last injection of azoxymethane. The tumor incidence and tumor yields (tumors per rat) of the colon were significantly lower in rats on the EPA diet compared to those on the linoleic acid diet; i.e., 33%, 0.41 +/- 0.61 and 69%, 1.66 +/- 1.69, respectively. In the analysis of phospholipid fatty acid composition, the colon tumor showed higher levels of arachidonic acid and lower levels of linoleic acid than those in the normal colon mucosa in both diet groups. Despite the increase of arachidonic acid in colon tumor, the EPA diet suppressed the excessive production of prostaglandin E2, which may be accompanied with neoplastic formation, whereas linoleic acid diet caused a marked increase in the tumor content of prostaglandin E2 compared to normal colon mucosa. These results suggest that EPA exerts its inhibitory effect on colon carcinogenesis by modulating lipid metabolism and inhibiting prostaglandin E2 synthesis in tumor cells.

Effect of dietary unsaturated and saturated fats on azoxymethane-induced colon carcinogenesis in rats.

The effects of dietary unsaturated and saturated fats on chemically induced colon carcinogenesis were examined in male Donryu rats. The rats were fed two types of semipurified diets consisting of 5% linoleic acid or 4.7% stearic acid plus 0.3% essential fatty acid as dietary fats. The rats were treated with azoxymethane (7.4 mg/kg body weight) s.c. once a week for 11 weeks and sacrificed 15 weeks after the last injection of the carcinogen. The rats fed unsaturated fat diet demonstrated a significantly higher incidence of colon tumors [100%], more tumors per rat [2.68 +/- 1.60 (S.D.)], and greater malignant differentiation histologically than did those fed saturated fat diet [76%, 1.79 +/- 1.59, respectively]. Lipid analysis of colon tumors and colon mucosa showed that unsaturated fat diet altered the phosphatide fatty acyl composition of colon mucosa markedly and increased the content of arachidonic acid in the neutral lipid of colon tumors. The altered lipid composition of the mucosa may increase the sensitivity of the colon to the carcinogen, and the excess of arachidonic acid or its metabolites may be the primary agents of cocarcinogenesis of colon tumors. These findings suggest that dietary unsaturated fats have potent cocarcinogenic effects on colon carcinogenesis.

Structure and transcriptional regulation of the mouse ferrochelatase gene.

Ferrochelatase (EC.4.99.1.1), the final step in the biosynthesis of heme, is widely expressed in various tissues and is induced in erythroid cells. We determined the structure of the mouse ferrochelatase gene after isolation and characterization of lambda phage clones mapping discrete regions of the cDNA. The gene spans about 25 kb and consists of 11 exons. The exon/intron boundary sequences conform to consensus acceptor (GTn)/donor (nAG) sequences, and exons in the gene encode functional protein domains. The promoter region contains multiple Sp1 sites, a CACCC box and GATA-1 binding sites. Function analysis of the promoter by transient transfection assay demonstrated that one Sp1 binding site located at -37/-32 is essential for basic expression of the ferrochelatase gene in both mouse erythroleukemia (MEL) and non-erythroid EL4 cells. In addition, the region (-66/-51) containing a CACCC box and the neighboring GC box partly contributes to the inducible activity of the reporter in MEL cells upon induction with dimethylsulfoxide. It appears that at least two promoter regions of the mouse ferrochelatase gene function in basic and inducible expression.

Morphological change, loss of deltapsi(m) and activation of caspases upon apoptosis of colorectal adenocarcinoma induced by 5-FU.

Apoptosis is clearly distinguished from necrosis, morphologically and chemically. Morphologically, apoptosis is characterized by a condensed nucleus and the disappearance of microvilli without disruption of the cytoplasm. In this report, we demonstrate that 5-fluorouracil (5-FU)-induced early apoptotic cells are characterized by (i) ultracondensed mitochondria, (ii) no change in the microvilli or nucleus, (iii) a high mitochondrial transmembrane potential (Deltapsi(m)), and (iv) being annexin V(negative). The early apoptotic cells also show the active forms of caspase 8 and caspase 9. They rapidly lose Deltapsi(m) after further incubation. Therefore, we conclude that the ultracondensation of mitochondria precedes the loss of Deltapsi(m) and the exposure of phosphatidylserine to the outer leaflet of the cell membrane.

Susceptibility to urethane carcinogenesis of transgenic mice carrying a human prototype c-Ha-ras gene (rasH2 mice) and its modification by butylhydroxytoluene.

The susceptibility of rasH2 mice to urethane lung carcinogenesis and the modifying effects of butylhydroxytoluene (BHT) on development of pulmonary lesions were examined. Single i.p. injections of urethane at 250 mg/kg in males or 500 mg/kg in females induced alveolar/bronchiolar adenomas within 6 weeks. At 4 weeks after the injection with a dose of 1000 mg/kg, adenomas occurred in both sexes. BHT administration increased the multiplicity of hyperplasias observed 3 weeks after the urethane injection and additionally caused adenomas which did not occur in the urethane alone-treated animals. The overall data suggest the possibility of rapid assays for lung carcinogens using rasH2 mice.

Validation of transgenic mice carrying the human prototype c-Ha-ras gene as a bioassay model for rapid carcinogenicity testing.

Carcinogenicity testing is indispensable for identifying environmental carcinogens and for evaluating the safety of drugs in the process of development. Conventional 2-year rodent bioassays are one of the most resource-consuming tests in terms of animals, time, and costs. Development of rapid carcinogenicity testing systems that can assess carcinogenicity within a short period has become a social demand and is essential to improve efficacy in the identification of environmental carcinogens as well as in the development of new drugs. In this review we introduce the rapid carcinogenicity testing system using transgenic (Tg) mice carrying the human prototype c-Ha-ras gene, namely rasH2 mouse (CB6F1-TgHras2 mouse is the same mouse). The studies have been conducted to validate the rasH2 mouse as a model for the rapid carcinogenicity testing system. Our current validation studies revealed that rasH2 mice are able to detect various types of mutagenic carcinogens within 6 months. The rasH2 mice may also be able to detect various nonmutagenic carcinogens. The validation studies also revealed that rasH2 mice are generally much more susceptible to both mutagenic and nonmutagenic carcinogens than control non-Tg mice. No significant tumor induction has been observed in rasH2 mice with either mutagenic or nonmutagenic noncarcinogens. More rapid onset and higher incidence of more malignant tumors can be expected with a high probability after treatment with various carcinogens in the rasH2 mice than in control non-Tg mice. The rasH2 mouse appears to be a promising candidate as an animal model for development of a rapid carcinogenicity testing system.

Role of x-linked immunodeficiency (xid) and NK activity in rejection of human tumor xenotransplants in nude mice.

In order to elucidate the factors influencing the takes of human tumor xenografts in nude mice, we compared the transplantability of human tumors in nude mice with additional genetic defects in the immune system. The nude mice strains tested were classified as follows by expression of the beige gene and the x-linked immunodeficiency (xid) gene: 1) high NK nude (C57BL/6N, nu/nu), 2) low NK nude (C57BL/6 bg/bg nu/nu), 3) high NK nude with B-cell defect (CBA/N nu/nu), and 4) low NK nude with B-cell defect (NIH(S)III). Takes of human tumor xenografts including gastric carcinoma, T-cell lymphoma and B-cell lymphoma were better in nude mice with xid (CBA/N and NIH(S) III nude mice) than in nude mice without xid (B6 and beige nude mice). In addition, among the nude mice with xid expression, the takes were slightly better in nude mice with a CBA/N background than in those with a NIH(S) background. Moreover, the xenotransplantation rate in (CBA/N x C57BL/6N)F1 male nude mice with xid expression was higher than in (C57BL/6N x CBA/N)F1 males without xid expression, but did not react the same level as that in CBA/N nude. On the other hand, introduction of the beige gene into nude mice minimally improved the takes of human tumor xenografts under limited experimental conditions (inoculation of 100 x 10(5) T-cell lymphoma and 1 x 10(5) gastric carcinoma cells) despite the reduction of NK activity. In xenotransplantation of human tumors directly from patients, the take rates of the tumors were also better in CBA/N nude mice than in BALB/cA nude mice. The results in the present report confirmed the effect of xid and CBA/N genetic background on human tumor xenografts in nude mice, suggesting the existence of serum factors, possibly present in serum IgM, mediating rejection of the xenografts.

Butylhydroxytoluene (BHT) increases susceptibility of transgenic rasH2 mice to lung carcinogenesis.

PURPOSE: Transgenic mice carrying the human prototype c-Ha-ras gene (rasH2 mice) are highly susceptible to lung carcinogens. In order to investigate the possibility of developing a rapid in vivo assay for lung carcinogens, we examined whether the tumor-promoting activity of butylhydroxytoluene (BHT) is efficacious in rasH2 mice. METHODS: rasH2 mice and wild littermates of both genders were pre-treated with carcinogens [urethane (UR), 4-nitroquinoline 1-oxide (4NQO) or diethylnitrosamine (DEN)], and, one day later, given a 400 mg/kg dose of BHT. RESULTS: Six weeks after the initiation treatment, evidence of carcinogenicity could be detected in male and female rasH2 mice that had received UR doses of > or = 250 mg/kg and > or = 125 mg/kg, respectively, prior to exposure to BHT, whereas only 500 mg/kg of UR was sufficient to induce tumors in female rasH2 mice given the carcinogen alone. The carcinogenicity of 15 mg/kg of 4NQO could be detected after 9 weeks in male rasH2 mice given the carcinogen followed by BHT. Similarly, the carcinogenicity of 60 mg/kg of DEN could be detected after 9 weeks and 6 weeks, respectively, in male and female rasH2 mice given the carcinogen followed by BHT. No carcinogenicity could be demonstrated through the experimental period with doses of 4NQO or DEN given alone. CONCLUSIONS: These results indicate that BHT administration increases the susceptibility of rasH2 mice to lung carcinogens, and suggest that the use of BHT in rasH2 mice might lead to the establishment of a rapid in vivo assay for lung carcinogens.

Resveratrol inhibits human breast cancer cell growth and may mitigate the effect of linoleic acid, a potent breast cancer cell stimulator.

Resveratrol is a naturally occurring product found in grapes and wine. The effect of synthetic resveratrol on the growth of estrogen receptor (ER)-positive (KPL-1 and MCF-7) and -negative (MKL-F) human breast cancer cell lines was examined. Resveratrol at low concentrations caused cell proliferation in ER-positive lines (KPL-1, < or = 22 microM; MCF-7, < or = 4 microM) whereas at high concentrations (> or = 44 microM) it caused suppression of cell growth in all three cell lines examined. Growth suppression was due to apoptosis as seen by the appearance of a sub-G1 fraction. The apoptosis cascade up-regulated Bax and Bak protein, down-regulated Bcl-xL protein, and activated caspase-3. Resveratrol (52-74 microM) antagonized the effect of linoleic acid, a potent breast cancer cell stimulator, and suppressed the growth of both ER-positive and -negative cell lines. Thus, resveratrol could be a promising anticancer agent for both hormone-dependent and hormone-independent breast cancers, and may mitigate the growth stimulatory effect of linoleic acid in the Western-style diet.

Effects of genistein and synergistic action in combination with eicosapentaenoic acid on the growth of breast cancer cell lines.

Genistein, a prominent isoflavone in soy products, produced dose- and time-dependent in vitro growth inhibition at high concentrations (at least 185 microM) with an IC50 of 7.0-274.2 microM after 72 h incubation in four breast cancer cell lines (DD-762, Sm-MT, MCF-7 and MDA-MB-231) and one breast epithelial cell line (HBL- 100) of human and animal origin; it stimulated estrogen-receptor-positive MCF-7 cells at low concentrations (3.7 nM-37 microM). Genistein-exposed cells underwent apoptosis, confirmed by G2/M arrest followed by the appearance of a sub-G1 fraction in cell-cycle progression, and by a characteristic cell ultrastructure. The apoptosis cascade was due to up-regulation of Bax protein, down-regulation of Bcl-XL protein, and activation of caspase-3. Genistein acted in synergism with eicosapentaenoic acid (EPA), a fish oil component, on human breast cancer MCF-7 cells (genistein > 93.2 microM and EPA > 210.9 microM) and on MDA-MB-231 cells (genistein > 176.1 microM and EPA > 609.3 microM). Dietary intake of genistein in combination with EPA may be beneficial for breast cancer control.

Cycloprodigiosin hydrochloride, a H+/Cl- symporter, induces apoptosis in human breast cancer cell lines.

The effect of cycloprodigiosin hydrochloride (cPrG.HCl), a H+/Cl- symporter, on five human breast cancer cell lines (KPL-1, T-47D, MCF-7, MKL-F, and MDA-MB-231), a human breast epithelial cell line (HBL-100), and a human fibroblast cell line (WI-38-40) was examined. cPrG.HCl inhibited the growth of all five breast cancer cell lines (IC50: 0.46-0.62 microM) and slightly inhibited HBL-100 and WI-38-40 cell growth (IC50: 1.75 microM and 2.26 microM respectively). cPrG.HCl treatment in KPL-1 cells increased the pH of acidic organelles, decreased intracellular pH, and caused apoptosis, which was confirmed by the appearance of a sub-G1 population by flow cytometry and DNA fragmentation. In addition, cPrG.HCl-induced apoptosis was strongly suppressed by imidazole, a cell-permeable base, suggesting that intracellular acidification was essential for the apoptosis. Further, cPrG.HCl treatment up-regulated Bax and Bak expression, down-regulated Bcl-2 expression, and activated caspase-3. Therefore, the intracellular acidification by cPrG.HCl treatment suppressed the growth of human breast cancer cell lines by inducing apoptosis.

Involvement of the tyrosine phosphorylation pathway in induction of human heme oxygenase-1 by hemin, sodium arsenite, and cadmium chloride.

The effect of a tyrosine kinase inhibitor, herbimycin A, on the induction of heme oxygenase-1 (HO-1) mRNA in HeLa cells upon exposure to hemin, sodium arsenite and cadmium chloride was examined. The induction of HO-1 mRNA by hemin was inhibited when the cells were pretreated with herbimycin A. Herbimycin also inhibited arsenite- and cadmium-dependent induction of HO-1 mRNA in a dose-dependent manner, but less inhibition was observed in cadmium-treated cells than in ones treated with hemin- or arsenite. Genistein (50 microM), another tyrosine kinase inhibitor, also inhibited the induction of HO-1 mRNA by hemin, arsenite, and cadmium. Nuclear runoff assays revealed that herbimycin blocked the hemin-induced transcription of the HO-1 gene. The induction of HO-1 mRNA by hemin in human peripheral blood mononuclear cells was inhibited by herbimycin. The tyrosine phosphorylation of a protein with a molecular mass of 66 kDa in the cells was increased by hemin- or arsenite-treatment, and this increase was inhibited by treatment with 5 microM herbimycin. When HeLa cells were treated with a specific inhibitor of the mitogen-activated protein kinase (MAPK)/extracellular-signal regulated kinase cascade, PD58059 (100 microM), suppression of the cadmium-dependent HO-1 induction was not observed, but the hemin- or arsenite-dependent induction was slightly inhibited. SB203580, an inhibitor of p38 MAPK, did not affect the HO-1 induction. These results indicated that signal transduction involving tyrosine kinase rather than the MAPK family regulates the induction of human HO-1 gene expression by stress inducers.

Strategy for lymphadenectomy of gastric cancer.

To determine the extent of lymphadenectomy necessary to cure early gastric cancer, the relationship between the frequency of nodal involvements and the extent of the primary invasion was examined in 274 patients with primary cancer of the stomach. We also evaluated the relationship between the number of metastatic lymph nodes, the pattern of metastases to the nodes, and the histologic type of the primary tumor. In early gastric cancer, lymph node metastasis was more frequent in protruded-type cancer with invasion into the submucosa more than 3 cm in diameter and located in the lower third of the stomach, but was limited to the group 1 lymph nodes, which were defined as being anatomically located nearest to the cancer. In cancer invading into the muscularis propria, metastasis to the group 2 or 3 lymph nodes, which were defined as being anatomically located farther from the cancer than group 1, was found. The number of lymph nodes involved and extent of cancer metastasis in these lymph nodes metastasis, differentiated early gastric cancer had more lymph node involvement and wider extent of metastases than undifferentiated cancers. The cancer cells sometimes replaced most of the node and invaded the perinodal fatty tissue, even in early gastric cancer. In addition, it is occasionally difficult to distinguish macroscopically early gastric cancer with submucosal invasion from cancer invaded into the muscle layer. In conclusion, group 1 and 2 lymph nodes, including perinodal fatty tissue, should be removed completely, even in early gastric cancer, except for carcinoma in situ, particularly when the cancer is of the differentiated type.

Site of action of galanin in the cholinergic transmission of guinea pig small intestine.

The mode and site of action of galanin were examined in the guinea pig small intestine. Galanin (3 x 10(-9)-10(-7) M) inhibited the twitch contractions of longitudinally and circularly oriented muscle strips mediated by the stimulation of cholinergic neurons, but not the contractions mediated by direct stimulation of smooth muscle cells with carbachol. Galanin (3 x 10(-9)-10(-7) M) inhibited both the electrically stimulated and the tetrodotoxin-resistant high K+ (40 mM)-induced increase of [3H]acetylcholine outflow from the ileal strips preloaded with [3H]choline, in a concentration dependent fashion. The inhibitory effect of galanin was antagonized by galantide and produced self-desensitization. The spontaneous and stimulated outflow of [3H]noradrenaline and [3H]gamma-aminobutyric acid were not affected by galanin even at 10(-7) M. Thus, galanin inhibits the motility of guinea pig ileum by inhibition of acetylcholine release from the enteric cholinergic neurons. Galanin may act on the specific receptor located on soma-dendritic regions and nerve terminals of cholinergic neurons.