Detection of Helicobacter pylori infection in early stage gastric cancer. A comparison between intestinal- and diffuse-type gastric adenocarcinomas

BACKGROUND

Helicobacter pylori (H pylori) infection has been suggested to be a risk factor for gastric carcinogenesis. However, those previous studies have been concerned with advanced cancer cases. To the authors' knowledge, no detailed investigation on the prevalence of H pylori in early stage gastric cancer tissue has been performed. The relationship between early stage gastric cancer and the prevalence of H pylori was studied by a immunohistochemical staining analysis.

METHODS

Sixty-eight patients who were endoscopically and surgically diagnosed as having early stage gastric cancer were enrolled in this study. All tissue specimens were obtained from patients by endoscopic biopsy, and were classified histopathologically as the intestinal-type of early stage gastric cancer in 34 patients (male-to-female ratio, 28:6; age, 64 +/- 11 years) and the diffuse-type of early stage gastric cancer (male-to-female ratio, 23:11; age, 57 +/- 14 years) in the other 34 patients. The amount of H pylori in tissue samples was graded from 0 (no characteristic bacteria) to 3 (numerous bacteria) using the fluorescent microscopic and an immunohistochemical technique.

RESULTS

Twenty-nine of the 34 cases of the intestinal-type of gastric cancer had H pylori infection, as compared with 11 of the 34 cases of diffuse-type early stage gastric cancer. A significantly higher incidence (85%; P < 0.001) of H pylori infection and, thus, higher grading scores of the number of H pylori were found in the intestinal-type early stage gastric cancer.

CONCLUSIONS

These findings suggest that the infection of H pylori may have a crucial relationship to the early stages of carcinogenesis of intestinal-type gastric cancer.

Effects of one-year cadmium exposure on livers and kidneys and their relation to glutathione levels

To study the effects of a long-term cadmium exposure on livers and kidneys, rats were administered cadmium chloride (0.228 mg Cd/kg, 3 days/week ip), for one year. Significant accumulation of cadmium was observed in livers (183 +/- 40 micrograms/g liver) and kidneys (92 +/- 17 micrograms/g kidney). Serum urea nitrogen and creatinine levels were significantly elevated in the cadmium-treated rats, while liver function tests were minimally affected. Histological observations showed interstitial fibrosis with minimal cell necrosis and inflammatory cell infiltration in livers, and apparent degeneration of proximal tubules and infiltration of inflammatory cells in parenchyma of kidneys. Lipid peroxidation in livers and kidneys, as assessed by thiobarbituric acid reactive substances, revealed no differences between the cadmium-treated rats and the controls. Glutathione contents were significantly increased in the cadmium treated rats both in livers (p < 0.001), and in kidneys (p < 0.001) compared with the controls. Increased glutathione levels in livers may contribute, in part, to the prevention of serious hepatotoxicity during chronic cadmium exposure, while nephrotoxicity due to cadmium may not be prevented by glutathione.

Detection and analysis of replicating hepatitis C virus RNA in hepatocellular carcinoma tissues

Although persistent hepatitis C virus infection is closely associated with the development of hepatocellular carcinoma, the nature of hepatitis C virus replication in the hepatocellular carcinoma tissue has not been fully characterized. To study this, carcinoma and non-carcinoma tissues were obtained from five patients with hepatocellular carcinoma. Total RNA was recovered from each tissue, and a portion of the envelope gene of replicating hepatitis C virus was amplified by minus-strand-specific reverse transcription and nested polymerase chain reaction. The amplified cDNA was examined by single strand conformation polymorphism analysis and sequencing. Hepatitis C virus replication was detected in both carcinoma and non-carcinoma tissues in four patients who were positive for serum hepatitis C virus markers. In one patient, a single species with identical envelope 2 genome was obtained from both carcinoma and non-carcinoma tissues. In the other three patients, the replicating hepatitis C virus existed as a mixture of 2-5 species with different but highly homologous (82-99%) envelope 2 genomes (quasispecies populations). The constitution of viral populations was different between carcinoma and non-carcinoma tissues. A total of ten sequences were recovered; four sequences were found in both tissues, two were found in carcinoma tissues, and four were found in non-carcinoma tissues. The difference in the constitution of quasispecies populations between carcinoma and non-carcinoma tissues confirms the unequivocal replication of hepatitis C virus in both tissues, and may imply the presence of different biological properties among hepatitis C virus with different sequences.

Expression of gap junction protein connexin 32 and E-cadherin in human hepatocellular carcinoma

The expression of connexin 32, a major gap junction protein, and E-cadherin, an intercellular adhesion molecule that is supposed to be involved in the regulation of gap junctional intercellular communications, was examined immunohistochemically in seven specimens of human hepatocellular carcinoma and surrounding non-carcinomatous tissues. We found that the number of connexin 32-positive spots per mm2 was significantly less in hepatocellular carcinoma tissues than in the surrounding non-carcinomatous cirrhotic tissues (4360 +/- 3390/mm2 vs 10,030 +/- 3690/mm2; p < 0.01). The number in the latter was also significantly less than that in normal controls (23,560 +/- 4170/mm2). E-cadherin was expressed in all non-carcinomatous hepatocytes as well as carcinomatous cells, except for one case of Edmondson's grade III hepatocellular carcinoma. These results suggest an impairment of cell-to-cell communications in human hepatocellular carcinomas.

Comparison of the hypervariable region of hepatitis C virus genomes in plasma and liver

Nucleotide sequences of the hypervariable region of hepatitis C virus genomes obtained from plasma change rapidly during the course of infection and are believed to play a part in immunological escape and consequently in the development of persistent infection. It is not known, however, whether these changes also occur in the liver. To clarify this aspect, RNA was extracted from the plasma and liver tissue of eight patients with chronic hepatitis C. After cDNA synthesis, DNA fragments that included the hypervariable region were amplified by the polymerase chain reaction. Consensus nucleotide sequences were determined directly from the polymerase chain reaction products by the dideoxy chain termination method. The diversity of the hypervariable region was analyzed further by the polymerase chain reaction-single strand conformation polymorphism analysis. Consensus nucleotide sequences of the hypervariable region were identical between the plasma and the liver in each patient. The polymerase chain reaction-single strand conformation polymorphism analysis showed multiple DNA bands that represented different hypervariable region sequences. Comparison of the single strand conformation polymorphism patterns revealed that the number, the mobility, and the density of bands were the same between the plasma and the liver. It is concluded that the population and the diversity of hepatitis C virus quasispecies as detected by the hypervariable region sequence are the same between the plasma and the liver despite rapid mutations, indicating that rapid changes in the population of hepatitis C virus quasispecies also occur in the liver.

Detection of Helicobacter pylori infection in early stage gastric cancer. A comparison between intestinal- and diffuse-type gastric adenocarcinomas

BACKGROUND

Helicobacter pylori (H pylori) infection has been suggested to be a risk factor for gastric carcinogenesis. However, those previous studies have been concerned with advanced cancer cases. To the authors' knowledge, no detailed investigation on the prevalence of H pylori in early stage gastric cancer tissue has been performed. The relationship between early stage gastric cancer and the prevalence of H pylori was studied by a immunohistochemical staining analysis.

METHODS

Sixty-eight patients who were endoscopically and surgically diagnosed as having early stage gastric cancer were enrolled in this study. All tissue specimens were obtained from patients by endoscopic biopsy, and were classified histopathologically as the intestinal-type of early stage gastric cancer in 34 patients (male-to-female ratio, 28:6; age, 64 +/- 11 years) and the diffuse-type of early stage gastric cancer (male-to-female ratio, 23:11; age, 57 +/- 14 years) in the other 34 patients. The amount of H pylori in tissue samples was graded from 0 (no characteristic bacteria) to 3 (numerous bacteria) using the fluorescent microscopic and an immunohistochemical technique.

RESULTS

Twenty-nine of the 34 cases of the intestinal-type of gastric cancer had H pylori infection, as compared with 11 of the 34 cases of diffuse-type early stage gastric cancer. A significantly higher incidence (85%; P < 0.001) of H pylori infection and, thus, higher grading scores of the number of H pylori were found in the intestinal-type early stage gastric cancer.

CONCLUSIONS

These findings suggest that the infection of H pylori may have a crucial relationship to the early stages of carcinogenesis of intestinal-type gastric cancer.

Increased renal susceptibility to gentamicin in the rat with obstructive jaundice. Role of lipid peroxidation

To study whether renal susceptibility to nephrotoxic stimuli is increased in obstructive jaundice, the effect of gentamicin on the renal function in bile duct-ligated rats was investigated. Gentamicin (50 mg/kg/day, subcutaneously) or saline was given to bile duct-ligated rats or sham-operated rats for six days. Mortality in the bile duct-ligated group that received gentamicin was 64% whereas that in the other groups was 0%. In the bile duct-ligated group, although serum creatinine and blood urea nitrogen were minimally affected, focal granulo-vacuolar degeneration in the proximal tubule was observed, which was accompanied by an increase in renal malondialdehyde. Gentamicin significantly increased serum creatinine and blood urea nitrogen levels and caused marked degeneration in the proximal tubule in the bile duct-ligated group, which was accompanied by a further increase in renal malondialdehyde, while these changes were not observed in the sham group. The kidney in obstructive jaundice appears to be susceptible to gentamicin. Enhanced production of oxygen radicals may be responsible for this effect.

Evaluation of the effects of esophageal varicosclerosants on local vascular occlusion and systemic blood coagulation

The efficacy and safety of the various sclerosants available for esophageal sclerotherapy have not been adequately investigated. In the present study, we experimentally evaluated the effects on local vascular occlusion and systemic blood coagulation of five sclerosants: 5% ethanolamine oleate, 99.5% ethanol, 2% aethoxysclerol, thrombin, and n-butyl-2-cyanoacrylate. The effects were tested after injection into the auricular vein of rabbits. Prothrombin time, activated partial thromboplastin time, plasma fibrinogen level, and peripheral blood platelet count were measured before injection and 5 minutes, 1 hour, 1 day, and 7 days later. Histologic examinations were then made of the auricular vein, lungs, liver, spleen, and kidneys. In the initial period after injection of ethanol or thrombin, fibrinogen level and platelet count were significantly reduced. Except for thrombin, none of the drugs affected prothrombin time or partial thromboplastin time. Local thrombosis took place after the injection of ethanolamine oleate, ethanol, and aethoxysclerol, whereas thrombin injection did not result in local thrombosis or vascular occlusion. Cyanoacrylate produced no local thrombus formation but caused vascular occlusion. Over-dosing of thrombin and ethanol led to sudden death of animals. These findings suggest that it is necessary to assess further the safety of intravascular use of thrombin, that the other drugs seem to be usable, and that careful consideration should be given to the excess use of ethanol in clinical settings. The present animal model may be useful for evaluating various sclerosants, although findings may not be applicable to humans because of differences in vascular size.

Effects of verapamil on hepatic glutathione in the rat

Effects of verapamil, an calcium channel blocker, on hepatic glutathione were studied in vivo in the rat and in the perfused rat liver. An injection of verapamil at a dose of 15 mg/kg body weight but not at 5 mg/kg significantly decreased hepatic glutathione contents in both fed and fasted animals 6 h after the injection. The administration of verapamil at a dose of 10 mg/kg twice a day for a week brought a significant decrease in hepatic glutathione contents and a significant increase in plasma glutathione levels. In the perfused rat liver, sinusoidal glutathione efflux was significantly increased when verapamil was added to the perfusion medium in a concentration of 20 microM. These data indicate that verapamil increases glutathione efflux from the liver and that calcium mobilization may be concerned in glutathione efflux in vivo.

ATP release evoked by isoprenaline from adrenergic nerves of guinea pig atrium

Mode and site of release of ATP evoked by isoprenaline were evaluated in the electrically driven left atrial segment of guinea pig. The peak release of ATP 5 min after 1 microM isoprenaline was inhibited by 1 microM propranolol and 1 microM butoxamine, but not by 1 microM atenolol, showing that the ATP release is due to stimulation of the presynaptic beta 2-adrenoceptor by isoprenaline. The maximum ATP release was markedly reduced by Ca2+/calmodulin antagonists, W-7 and trifluoperazine, and by a mitotic inhibitor, vinblastine. Further, the release was similarly inhibited by myosin light chain kinase inhibitors, ML-7 and wortmannin. Nifedipine, a Ca(2+)-channel blocker, decreased the release of ATP evoked by isoprenaline. By contrast, Bay K 8644, a Ca(2+)-channel opener, tended to enhance the ATP release. These findings suggest that isoprenaline produces ATP release from adrenergic nerve terminals of atrium, implying that ATP serves as a co-transmitter.

A variant alkaline phosphatase found in a case of gastric carcinoma with super bone scan

A rare case of gastric carcinoma associated with increased serum variant alkaline phosphatase activities is presented. A 54 year old man had extremely high serum alkaline phosphatase activity (18,607 U/l) with normal calcium and phosphate concentrations. His bone scintigram showed abnormal findings, 'super bone scan'. He was diagnosed as having Borrmann type 4 gastric carcinoma with diffuse bone metastases by examinations of the upper gastrointestinal tract and iliac bone biopsy. The alkaline phosphatase isozyme of this patient was of the bone type as measured by cellulose acetate membrane electrophoresis and the placenta/bone type by agarose gel electrophoresis, respectively. Immunoelectrophoresis and the immunoprecipitation method using monoclonal antibodies against various alkaline phosphatase isozymes, however, showed that his serum alkaline phosphatase had the liver type antigenicity. Furthermore, it had a larger molecular size and different sugar chains compared with the common liver type alkaline phosphatase. These findings suggest that a unique variant alkaline phosphatase was produced by gastric cancer cells, which is possibly an explanation for the high serum alkaline phosphatase activities in this patient.

Co-administration of insulin-like growth factor (IGF)-I and IGF-binding protein-1 stimulates wound healing in animal models

The stimulatory effect of recombinant human insulin-like growth factor-I (rhIGF-I) and recombinant human insulin-like growth-factor-binding protein-1 (rhIGFBP-1) on wound healing was assessed using diabetic db/db mice and normal rabbits. Full-thickness wounds of 6 mm diameter were prepared on the backs of diabetic C57BL/KsJ db/db mice and on the inner sides of normal rabbit ears. Various concentrations of rhIGF-I and/or rhIGFBP-1 were applied locally to the open wounds of db/db mice once daily for 5 d and to the covered wounds of normal rabbits once after wounding. Sections of the wounds were evaluated histologically on the seventh or eighth day by measuring re-epithelialization (%), area of granulation tissue (mm2), and capillary numbers. Wound repair was accelerated by each of the treatments in descending order of rhIGF-I plus rhIGFBP-1, rhIGF-I, rhIGFBP-1, and vehicle alone. In db/db mice, the combination of 50 micrograms rhIGF-I and 165 micrograms rhIGFBP-1 (equimolar ratio) significantly stimulated granulation tissue formation (p < 0.01) and capillary numbers (p < 0.05). Doses of rhIGFBP-1 greater than 16.5 micrograms were required for significant acceleration of the healing stimulated by 50 micrograms of rhIGF-I. In normal rabbits, co-administration of 10 micrograms rhIGF-I and 33 micrograms rhIGFBP-1 (equimolar ratio) significantly stimulated all three wound-healing parameters (p < 0.01), with such stimulation being much greater than that induced by rhIGF-I alone. Interestingly, rhIGFBP-1 alone showed a mild stimulatory activity on wound healing in both models despite its lack of mitogenic activity in vitro. These results demonstrate that rhIGFBP-1 enhances the stimulatory activity of rhIGF-I on wound healing and suggest the clinical utility of the co-administration of rhIGF-I and rhIGFBP-1 for wound repair.

Neuronal specificity of subtype SQSC1 of squid putative sodium channel

The distribution of SQSC1 mRNA in tissues of squid Loligo bleekeri was studied by the blot hybridization method. The complete cDNA for the coding region of SQSC1, the invertebrate putative sodium channel, was prepared from squid optic lobe (Sato and Matsumoto, Biochem. Biophys. Res. Comm. 186, 61-68, 1992). Transcriptional products of the SQSC1 gene were found to consist of two main different lengths (12 and 9 kb). The transcriptional products were detected in all the nervous tissues examined: optic lobes, cerebral ganglia and giant stellate ganglia. However, it was not detected in the muscle, suggesting the SQSC1 gene is specific for sodium channels of squid nerve cells. SQSC1 appears more widely distributed in the nervous system than GFLN1 which they reported as expressed specifically in stellate ganglion of the squid (Rosenthal and Gilly, Proc. Natl. Acad. Sci. USA 90, 10026-10030, 1993).

Increased gene expression of water channel in cirrhotic rat kidneys

In patients with liver cirrhosis, impaired water and sodium excretion has been incriminated in the pathogenesis of ascites formation. Increased reabsorption of water in the distal nephron has been shown to play an important role in water retention in cirrhotic rat kidneys. Recently, a complementary DNA (cDNA) for the vasopressin-regulated water channel (the aquaporin of the apical membrane of the kidney collecting duct [AQP-CD]) has been cloned. It is suggested that AQP-CD plays an important role in renal water handling. Therefore, in the present study, to investigate the pathogenic role of the water channel in water retention in liver cirrhosis, gene expression of AQP-CD in the kidney was evaluated in cirrhotic rats. Liver cirrhosis was induced by an intraperitoneal administration of carbon tetrachloride twice a week for 12 weeks in 14 rats. Messenger RNA expression of AQP-CD in whole kidney homogenates determined by Northern blot hybridization was significantly increased in cirrhotic rats (147%; P < .01) and dehydrated rats (206%; P < .0001) compared with control rats. Protein expression of AQP-CD in the homogenates of kidney medulla determined by Western blot analysis was significantly increased in cirrhotic rats (203%; P < .03) compared with control rats. Furthermore, mRNA expression of AQP-CD in the kidney showed a significant correlation with the volume of ascites in cirrhotic rats (r = .62, P < .02). No significant difference was observed in water intake, urinary volume, serum osmolality, serum sodium, and creatinine clearance between control and cirrhotic rats, suggesting that dehydration was unlikely in cirrhotic rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Long-term ingestion of lactosucrose increases Bifidobacterium sp. in human fecal flora

We investigated the influence of lactosucrose on the intestinal flora of healthy volunteers. Eight healthy volunteers (male:female = 4:4, age 34 +/- 4 years) received 6 g of lactosucrose daily for 8 weeks. Fecal microflora, bacterial metabolites, pH, and moisture were analyzed before and after the administration of lactosucrose. The results showed that the number and percentage of Bifidobacterium sp. in relation to the total bacteria significantly increased during the period of lactosucrose administration. Although fecal putrefactive products, fatty acids, pH, moisture content, and stool volume did not show significant changes during the test period, the amount of fecal phenol showed a negative correlation with the number of Bifidobacterium sp. Fecal ammonia significantly decreased after 4 and 8 weeks of lactosucrose administration, and 1 week after the end of lactosucrose administration, compared with results after a 1-week administration of lactosucrose. When the administration was stopped, the percentage of Bifidobacterium sp. in relation to the total count gradually decreased to the same level as before the administration of lactosucrose. These results suggest that under physiological conditions, lactosucrose acts on the intestinal microflora as a growth factor of Bifidobacterium sp.

Evolution and selection of hepatitis C virus variants in patients with chronic hepatitis C

It has been shown that hepatitis C virus (HCV) populations in vivo are composed of different but highly homologous HCV genomes (quasispecies) as shown in the hypervariable region (HVR) that exists in the N-terminal of the envelope 2 gene of HCV, and that the predominant sequence of the HVR of HCV genomes changes rapidly over time. To further investigate genetic backgrounds of the change in the HVR of HCV genomes, 45 plasma samples serially obtained from nine patients with chronic hepatitis C were studied using population-based analyses. Total RNA was recovered and the envelope gene containing the HVR was amplified by the reverse transcription and nested polymerase chain reaction. The amplified cDNA was examined by the single strand conformation polymorphism (SSCP) analysis. Furthermore, 43 HCV sequences, separated by the SSCP analysis from three patients were determined by the dideoxy chain termination method, and the phylogenetic analysis was performed using the neighbor joining method. The SSCP analysis demonstrated that HCV population within each individual were composed of 1 to 6 quasispecies. These quasispecies populations in vivo changed sequentially in eight of nine patients. Gradual selections of coexisting quasispecies were observed over 6- to 18-month periods in three patients, whereas complete replacements of previous quasispecies by new quasispecies were repeatedly observed over few-month intervals in five patients. The phylogenetic analysis on these quasispecies revealed the continuous accumulation of mutations in two patients and discontinuous appearance of evolutionarily distant quasispecies in one patient. These results indicate that HCV genomes in vivo form quasispecies populations, and that these quasispecies populations change during the natural course of chronic infection. Genetic mechanisms underlining the change of the HVR of HCV genome appear to be either continuous accumulation of mutations or selective overgrowth of preexisting minor variants from the large spectrum of quasispecies populations.

Characterization of glutathione efflux from Hep G2 cells

Previous studies have suggested that both cAMP-dependent signal transduction pathway and Ca2+/protein kinase C-dependent pathway are involved in GSH efflux from hepatocytes. In the present study, GSH efflux from Hep G2 cells, a human-derived hepatoma cell line, was further characterized. Both epidermal growth factor (0.1-10 ng/ml) and insulin (1 microgram/ml) significantly increased GSH efflux from Hep G2 cells. A fall in the membrane potential produced by the replacement of Na+ with equivalent K+ did not affect GSH efflux significantly. Neither ouabain, a Na+/K+ ATPase inhibitor, vanadate, a Ca2+ ATPase inhibitor, nor BaCl2, a K+ channel blocker, significantly affected the GSH efflux. Methionine (1mM) decreased GSH efflux from the cells, although total GSH content in the cells was not affected during the incubation time of 60 min. Signal transductions through tyrosine kinase-coupled receptors may also be involved in GSH efflux from hepatocytes.

Focal hepatocellular necrosis and portal lymphocytic infiltration of the liver in chronic alcoholics: histopathological study of 40 liver biopsies

Forty liver biopsies of hepatitis B surface antigen negative chronic alcoholics were histologically studied to assess the influence of hepatitis C virus (HCV)-infection. A moderate degree of focal hepatocellular necrosis and/or portal lymphocytic infiltration (FHN-PLI) was observed in 28% of the specimens, being especially prevalent in advanced cases of fibrosis and cirrhosis, and significantly correlated with HCV-infection. Eleven of these cases were examined in detail: HCV-infection was detected in eight and lymphocytic infiltration was apparent in the portal area, accompanied by formation of lymph follicles. The FHN-PLI was ascribed to alcoholic hepatitis in two HCV-negative cases and was concluded to be of unknown etiology in the remaining one HCV-negative case. This study thus indicated that over two-thirds of cases of chronic hepatitis in alcoholics can be attributed to HCV-infection, with the remainder being at least partly related to alcoholic hepatitis. The prevalence of alcohol-induced chronic hepatitis based on immunopathological findings was unclear, but was probably less frequent than previously reported.

Mineralocorticoid type I receptor in the rat cochlea: mRNA identification by polymerase chain reaction (PCR) and in situ hybridization

Expression of mineralocorticoid type I receptor (MR) gene in the rat cochlea was determined using molecular biological techniques. We synthesized complementary DNA (cDNA) from rat cochlear total RNA and then amplified MR cDNA fragments by polymerase chain reaction (PCR). The amplified cDNA fragments were subcloned into an expression vector and the nucleotide sequence was analyzed to confirm the expression of mRNA encoding MR in the cochlea. We then synthesized digoxigenin-labeled riboprobes with this cloned DNA template and examined the localization of MR mRNA in the cochlea by in situ hybridization. The amino acid sequence of MR cDNA expressed in the cochlea was identical to that of the MR first cloned in the rat hippocampus. In situ hybridization showed the expression of MR mRNA in marginal cells of the stria vascularis, suggesting that aldosterone may regulate microhomeostasis of the endolymph, presumably by modulating Na, K-ATPase activity. Intense MR signal was also identified in spiral ganglion cells, the function of which remains to be determined.

[Fluctuation of HCV quasi-species population during interferon therapy; analysis by single strand conformation polymorphism]

We investigated the fluctuation of hepatitis C virus (HCV) quasispecies during interferon therapy by single strand conformation polymorphism (SSCP) analysis. In 13 of 16 interferon ineffective patients, the predominant HCV population was replaced with other quasispecies during the treatment. Especially, in 9 patients, a part of the HCV quasispecies, pre-existing before interferon therapy, became predominant after the therapy. These results indicate that sensitivity to interferon differs among HCV quasispecies and that interferon selects resistant HCV strains. Existence of such HCV quasispecies seems to be associated with interferon treatment failure.