A specific Streptococcus mutans strain aggravates non-alcoholic fatty liver disease.

OBJECTIVE: Streptococcus mutans, a major dental caries pathogen, has shown to be associated with the aggravation of cerebral hemorrhage and inflammatory bowel diseases. In this study, we evaluated the effects ofS. mutans on the development of non-alcoholic steatohepatitis (NASH) in a mouse model. MATERIALS AND METHODS: Streptococcus mutans oral strain MT8148 (serotype c) and a blood isolate TW871 (k) were used. C57BL/6J mice (6 weeks old)were fed a high-fat diet for 4 weeks; the test strains or phosphate-buffered saline was then intravenously administered. Mice were euthanized after 8 or 12 weeks. Whole body, extirpated liver, and visceral fat weights were determined, and histopathological evaluations of the liver specimens were performed. RESULTS: Mice infected with TW871 showed significantly greater body and liver weights than those administered MT8148 or phosphate-buffered saline. Histopathological analyses revealed prominent infiltration of inflammatory cells and adipocellular deposition in livers extirpated 8 weeks after an infection with TW871; fibrosis was also observed in livers extirpated after 12 weeks. CONCLUSION: These results suggest that a specific strain of S. mutans could induce NASH.

Aggravation of inflammatory bowel diseases by oral streptococci.

OBJECTIVES: Streptococcus mutans can aggravate colitis in mice. We evaluated the virulence of colitis using type strains as well as blood isolates of several oral streptococcal species. MATERIALS AND METHODS: We investigated the susceptibility of blood isolates of several oral streptococci to phagocytosis, adhesion to and invasion of hepatic cells and interferon-γ secretion. A mouse model of dextran sodium sulphate-induced colitis was used to evaluate bacterial aggravation of colitis. In addition, interferon-γ antibody was administered to mice with prominent aggravation of colitis. RESULTS: In vitro analyses showed that Streptococcus sanguinis ATCC 10556 was a possible virulent strain among type strains of several oral streptococci, and that analysis of blood isolates of S. sanguinis TW289 revealed a potential virulent strain. Intravenous administration of ATCC 10556 and TW289 caused prominent aggravation of dextran sodium sulphate-induced colitis, and histopathological examinations showed that interferon-γ secretion due to infection of hepatic cells caused colitis aggravation. Administration of interferon-γ antibody suppressed TW289-induced colitis. CONCLUSION: These results suggest that some virulent oral streptococcal strains are associated with the aggravation of colitis induced by enhanced secretion of interferon-γ when they invade the bloodstream.

Potential involvement of collagen-binding proteins of Streptococcus mutans in infective endocarditis.

OBJECTIVE: Streptococcus mutans, a major pathogen of dental caries, is considered to be one of the causative agents of infective endocarditis (IE). Two types of cell surface collagen-binding proteins, Cnm and Cbm, have been identified in the organism. The aim of the present study was to analyze these proteins as possible etiologic factors for IE. MATERIALS AND METHODS: The binding activities of S. mutans strains to collagen types I, III, and IV were analyzed relative to the presence of Cnm and Cbm, as were their adhesion and invasion properties with human umbilical vein endothelial cells (HUVEC). In addition, distributions of the genes encoding Cnm and Cbm in S. mutans-positive heart valve specimens extirpated from IE and non-IE patients were analyzed by PCR. RESULTS: Most of the Cbm-positive strains showed higher levels of binding to type I collagen as well as higher rates of adhesion and invasion with HUVEC as compared to the Cnm-positive strains. Furthermore, the gene encoding Cbm was detected significantly more frequently in heart valve specimens from IE patients than from non-IE patients. CONCLUSIONS: These results suggest that the collagen-binding protein Cbm of S. mutans may be one of the potential important factor associated with the pathogenesis of IE.

Characterization of aortic aneurysms in cardiovascular disease patients harboring Porphyromonas gingivalis.

OBJECTIVE: Porphyromonas gingivalis was recently shown to cause intimal hyperplasia in a mouse model by a novel cholesterol-independent mechanism, suggesting to be a pathogen-specific feature of cardiovascular diseases. The aim of this study was to characterize the clinical and histopathological features of aortic aneurysms in cardiovascular disease patients harboring oral P. gingivalis. SUBJECT AND METHODS: Aortic aneurysm specimens were collected from 76 Japanese patients who underwent surgery, of whom dental plaque specimens were also collected from 31 patients. Bacterial DNA was extracted from each specimen to detect P. gingivalis by polymerase chain reaction. Histopathological analyses of the aortic aneurysm specimens, including immunohistochemical staining for embryonic myosin heavy chain isoform (SMemb) and S100 calcium-binding protein A9 (S100A9), were also performed. RESULTS: The number of aneurysms occurring in the distal aorta was significantly higher in subjects positive for P. gingivalis in dental plaque compared with those who were negative. The expressions of S100A9 and SMemb were also significantly greater in the subjects positive for P. gingivalis in dental plaque. On the other hand, there were no significant differences in adipocellular accumulation between the groups. CONCLUSIONS: These results suggest that aortic aneurysms in patients harboring oral P. gingivalis have greater expression of S100A9 and proliferative smooth muscle cells, which was different from the present patients without oral P. gingivalis.

Gastric submucosa as the safer and repeatable site for hepatocyte transplantation.

To establish a safe repeatable method for hepatocyte transplantation avoiding serious complications, such as portal thrombosis in the case of the intraportal route of transplantation, we attempted liver cell transplantation into the submucosal layer of the stomach wall. Hepatocytes were isolated from the Lewis rats by a two-step collagenase perfusion method. The final hepatocyte suspension containing 2 x 10(7) viable hepatocytes in 1 mL of 0.2% collagen gel solution. Recipient rats underwent 20% partial hepatectomy and the hepatocyte suspension (2 x 10(7) cells) was injected into the submucosal layer of the anterior wall of the stomach. Rats were humanely killed and histologically examined at days 1, 3, 7, 30, or 180. Most transplanted hepatocytes remained in the submucosal layer until day 7. The surviving hepatocytes were arranged in clusters in the submucosa on day 30; 5-bromo-2'-deoxy-uridine (BrdU)-positive cells were observed. Also, the function of glycogen storage was detected by Periodic acid-Schiff (PAS) reactions on days 7, 30, and 180. The transplanted hepatocytes proliferated, reconstructing liver tissue-like structures in the gastric submucosa on day 180. The gastric submucosa is easily, repeatedly accessible by the gastro-endoscope. Thus, these results suggest that the gastric submucosa is a possible site for safe repetitions hepatocyte transplantation using endoscopic injection.

Bile salt tauroursodeoxycholic acid modulation of Bax translocation to mitochondria protects the liver from warm ischemia-reperfusion injury in the rat.

BACKGROUND: Tauroursodeoxycholic acid (TUDC) is a hydrophilic bile acid that has a cytoprotective effect in primary biliary cirrhosis and primary sclerosing cholangitis. TUDC also protects hepatocytes from hydrophobic bile acid-induced apoptosis. The aim of this study was to determine whether TUDC ameliorates hepatocyte apoptosis during ischemia-reperfusion injury. METHODS: We used a rat model of hepatic warm ischemia-reperfusion injury to assess the effects of TUDC. Male Sprague-Dawley rats were subjected to 1 or 2 hr of normothermic ischemia followed by 3 or 6 hr of reperfusion. The treatment group received TUDC (50 mg/kg) by bolus intravenous injection 30 min before initiation of ischemia, whereas the control group received saline only. Blood samples for biochemical analysis were obtained after 6 hr of reperfusion. Liver biopsies for histological assessment were obtained 3 and 6 hr after reperfusion. Hepatocyte apoptosis was determined by terminal dUTP nick-end labeling. The pro-apoptotic protein Bax was quantified at the mRNA and protein level. RESULTS: Treatment with TUDC significantly reduced serum transaminase levels. This was associated with a significant amelioration in the levels of hepatocyte apoptosis in the TUDC-treated group compared with control. Furthermore, Western blot analysis of Bax expression in liver tissue indicated that TUDC inhibited the translocation of Bax from the cytosol to the mitochondria. CONCLUSIONS: TUDC significantly reduced hepatic injury in this model. The beneficial effects of TUDC upon hepatocyte apoptosis were related to the modulation of Bax protein translocation.

Interleukin-1 and tumor necrosis factor alter plasma concentration and interorgan fluxes of taurine in dogs.

We examined the effects of interleukin-1 beta (IL-1), tumor necrosis factor (TNF), and alanylglutamine (Ala-Gln) infusion on the plasma concentrations and interorgan fluxes of taurine and taurine precursors, including methionine and serine, using chronically catheterized awake dogs. In the first study, the dogs received 5 micrograms/kg/h of either human recombinant IL-1 or TNF intravenously for 2 h. Taurine fluxes in the liver and gut were calculated by blood flows and arteriovenous differences during infusion and for 2 h after discontinuation of the cytokine infusions. The 2 h continuous infusions of TNF and IL-1 resulted in 60 and 90% increases, respectively, in the arterial plasma taurine concentration. Hepatic taurine flux changed from uptake to release after 2 h of continuous IL-1 infusion. In the second study, we investigated whether Ala-Gln infusion affects taurine metabolism under normal and stress conditions. The dogs were given a constant 2 h intravenous infusion of IL-1 or saline. Ala-Gln (6 mumol/kg/min) was infused simultaneously during the second hour. Plasma concentrations and fluxes, across the liver, gut, and lung, of taurine and taurine precursors were studied. IL-1 administration increased the plasma concentration, hepatic release, and lung uptake of taurine. Ala-Gln infusion did not affect either plasma concentrations or organ fluxes of taurine. These data suggest that cytokines play a role in taurine metabolism under stress conditions.

Campylobacter jejuni enteritis in Honolulu, Hawaii.

The incidence of Campylobacter jejuni in patients with acute diarrhoea was studied in Honolulu, Hawaii. C. jejuni was recovered from 8.7% of diarrhoeal stools, compared to isolation rates of 4.2% for Salmonella and 3.8% for Shigella. C. jejuni occurred mainly in the summer and autumn, and in all age and racial groups. There was a significantly higher incidence of abdominal pain, fever history, bloody stools and faecal leucocytes in patients with Campylobacter enteritis.

Inhibition of growth of human breast cancer cells in culture by neutron capture using liposomes containing 10B.

Cell destruction in boron neutron capture therapy is effected by nuclear reaction between 10B and thermal neutrons with the release of alpha-particles (4He) and lithium-7 ions (7Li). 4He kills cells within 10 microm of the site of 4He generation, therefore it is theoretically possible to destroy tumour cells without affecting adjacent healthy tissue, given selective delivery of compounds containing 10B. Liposomes wore prepared by vortex dispersion of solutions containing 10B compounds with dried lipid films and the effects of those compounds on human breast cancer cells in culture were examined after thermal neutral irradiation. [3H]-TdR incorporation by MRKnu/nu-1 cells treated with 10B-containing liposomes showed 40% suppression compared with liposomes without 10B, at 2 x 1012 n/cm2 thermal neutron fluence. Inhibition of tumour cell growth with liposomes prepared with 100 mm 10B-compound was as significant as with those made with 500 ppm 10B solution. The concentration of 10B in liposomes was 76.5 +/- 3.4 microg/mL. Boronated liposomes can thus deliver sufficient 10B atoms to this line of breast cancer cells in culture to effect cytotoxicity and suppression of growth after thermal neutron irradiation.

Development of the vitamin A-storing cell in mouse liver during late fetal and neonatal periods.

Vitamin A-storing cells in perinatal mouse liver were studied by chemical and autoradiographic analyses of exogenous vitamin A. The amount of retinyl palmitate in the fetal liver increased significantly following oral administration of retinyl acetate to the mother, suggesting the existence of storage sites of the vitamin in fetal liver. Light microscope semi-serial autoradiography of the fetal liver on the 15th day of gestation showed that 3H-vitamin A administered to the mother was incorporated into cells distributed exclusively along the hepatic blood vessels and the blood islands. Mitotic figures of the labeled cells were frequently observed. Electron microscope autoradiography revealed that the vitamin was incorporated into lipid droplets, rough endoplasmic reticulum and Golgi apparatus of the fibroblast-like cells in close apposition to the endothelial cells. The labeled cells differed in their ultrastructure from the vitamin A-storing cells (Ito cells) of the adult liver. In the later gestational period, silver grains tended to be more concentrated in lipid droplets, and the cytological features of the labeled cells became similar to those of the vitamin A-storing cells. Both retinyl palmitate content and the labeling of lipid droplets increased rapidly in the liver of neonates after commencement of suckling. The labeled cells had the same appearance as the vitamin A-storing cells (Ito cells). It is concluded that vitamin A transported across the placenta is taken up in the fetal liver by the cells distributed along the blood vessels, and that these cells proliferate in accordance with vascular development and gradually take on the characteristics of vitamin A-storing cells during the perinatal period. A defensive role of the vitamin A-storing cell against the toxic effects of vitamin A is also suggested.

Glutamine-enriched enteral diet enhances bacterial clearance in protected bacterial peritonitis, regardless of glutamine form.

BACKGROUND: The effects of glutamine (Gln)-enriched enteral diets on bacterial clearance were investigated in a rat protracted peritonitis model. The effects of the Gln form, peptide-based vs free amino acid-based, were also compared. METHODS: Twenty-three rats underwent gastrostomy. An osmotic pump was implanted in the peritoneal cavity. The rats received a continuous intragastric infusion of one of three diets: Gln-depleted (Gln 0), Gln-enriched with the Gln in free amino acid form (Gln F), or Gln-enriched with the Gln in oligopeptide form (Gln P). The three formulas were isocaloric and isonitrogenous. The pumps delivered a continuous infusion of Escherichia coli, starting at 48 hours after implantation, for 24 hours. Then, the animals were killed. RESULTS: Bacterial numbers in peritoneal lavaged fluid (PLF) and the liver were significantly lower in the Gln P and Gln F groups than in the Gln 0 group. The bacterial number in PLF correlated with that in the liver. Neither the number nor the population of peritoneal exudative cells differed among groups. Plasma levels of proline, alanine and citrulline were significantly higher in the Gln P and Gln F groups than in the Gln 0 group. Both Gln supplemented groups showed significantly greater villous height, crypt depth, and numbers of mitoses per crypt in the small intestine than the Gln 0 group. CONCLUSIONS: Supplemental Gln enhances peritoneal and hepatic bacterial clearance, regardless of Gln form. Gln-enriched may be more beneficial than Gln-depleted enteral diets in peritonitis.

Alanyl-glutamine-supplemented total parenteral nutrition improves survival and protein metabolism in rat protracted bacterial peritonitis model.

BACKGROUND: The effects of glutamine-enriched total parenteral nutrition (TPN) solution on survival, and protein turnover in the whole body and in individual organs were investigated in a rat protracted peritonitis model. METHODS: Twenty-three rats underwent venous catheter insertion. Osmotic pumps were implanted in the peritoneal cavity to allow continuous delivery of Escherichia coli (4 x 10(8) CFU/d). The conventional TPN group received a conventional amino acid solution. The Ala-Gln TPN group received an alanyl-glutamine-enriched TPN solution. The two TPN solutions were isocaloric and isonitrogenous. RESULTS: Over the 5 days of TPN treatment, the survival rate of the Ala-Gln group was significantly higher than that of the conventional group. The Ala-Gln group tended to have increased whole-body protein turnover compared with the conventional group. Fractional protein synthetic rates (FSR) in the liver and gastrocnemius muscle of the Ala-Gln group were significantly higher than those of the conventional group. The serum glutamine concentration correlated positively with the FSR of both liver and muscle. The Ala-Gln group showed significantly greater mucosal height and mitoses per crypt, in the small intestine, than did the conventional group. CONCLUSIONS: Our results suggested that, in comparison with standard glutamine-free TPN, Ala-Gln-supplemented TPN increases protein synthesis in the liver and skeletal muscle, protects the morphology of the intestinal mucosa, and improves survival in protracted bacterial peritonitis. Ala-Gln supplementation may be useful in septic patients.

Factors affecting attitudes towards mother-to-child transmission of HIV among pregnant women in a maternal and child hospital in Thailand.

This study determines the factors which correlate with attitudes towards mother-to-child transmission of HIV in pregnant women. Using a structured questionnaire, 527 pregnant women who visited a hospital to have prenatal checkups were interviewed. The survey items were: sociodemographic characteristics, experiences of pre-test counselling, knowledge of mother-to-child transmission, and attitude towards termination of pregnancy. Results showed that many pregnant women (80%) did not have proper knowledge of the possibility of mother-to-child transmission. Logistic regression analysis also indicates that age and knowledge of the possibility of mother-to-child transmission were the significant determinants of attitudes towards termination of pregnancy. Older women who believe that all the babies of pregnant women with HIV will be infected are most likely to terminate their pregnancy when they are diagnosed as HIV positive. Considering the importance of informed decisions regarding pregnancy, this study must have important implications for future support programmes for HIV-positive pregnant women.

Pancreatic trauma in patients with pancreatobiliary anomaly.

One patient with a choledochal cyst and anomalous pancreaticobiliary junction had pancreatic transection causing bile peritonitis. Intraoperative cholangiopancreatography revealed this anomaly. In another patient with pancreas divisum, cannulation of the minor papilla (ERCP) demonstrated focal stenosis of the dorsal pancreatic duct, corresponding to the site of the minor laceration. The possibility of a coexisting pancreatobiliary anomaly should be considered in the diagnosis of pancreatic trauma, particularly in terms of the interpretation of pancreatograms.

[A case of gastric cancer with multiple liver metastasis responding to combined chemotherapy with low-dose cisplatin and 5-fluorouracil].

A 68-year-old man who had Borrmann type 4 gastric cancer with multiple liver metastases was admitted to our hospital on October 20, 1998. He was considered nonresectable and placed on neoadjuvant chemotherapy consisting of low-dose CDDP and 5-FU. After 9 weeks of administration, the liver metastases had disappeared on abdominal computed tomography, but the primary lesion had progressed. On May 12, 1999, a total gastrectomy with a partial resection of the transverse colon and resectional biopsy of a white nodule of the liver were performed. This was a non-curative operation because of the peritoneal dissemination. A histopathological examination of the liver nodule revealed that the cancer cells had disappeared. The patient had an uneventful postoperative course and 4 weeks of chemotherapy were added. He remains alive with no symptoms or re-growth of the liver metastatic tumor 4 months after the surgery.

[Tumor ablation with MRI navigation--a novel method of microwave coagulation therapy for hepatic tumor].

Fifty-eight patients with hepatic tumor which consisted of 22 hepatocellular carcinomas and 36 metastatic liver tumors were treated by microwave coagulation therapy with MRI navigation. The tumors were located in all segments of liver except S1. In 24 cases among them, the abdominal approach was difficult, because the tumors were located just below the diaphragm. These cases were selected for thoracoscope-assisted microwave ablation under MR-guidance across the diaphragm. All MR data were collected on a vertically oriented open MRI system (0.5 T SIGNA SP/i system: GE Medical Systems). The microwave electrode was introduced into the liver through a 14G needle via a percutaneous puncture with real-time MR image navigation. Microwave ablations at 60 W for 60 seconds were repeated several times depending on the tumor size. MR imaging may be employed as a reliable guide for percutaneous puncture. Moreover, sufficient safety margin could be obtained for hepatic tumor ablation. MR-guided microwave thermoablation therapy is a feasible method of treatment for hepatic tumors.

[Electrophysiologic and histopathologic investigations in children with idiopathic ventricular arrhythmias].

Between April 1984 and December 1987, electrophysiological studies and endomyocardial biopsy were performed in 14 pediatric patients, aged from 7 to 15 years, with idiopathic ventricular arrhythmias in whom diagnostic evaluation had revealed no structural heart disease. They were 8 boys and 6 girls. Cardiac catheterization revealed regional wall motion abnormalities of the left ventricle in 3 patients, one of whom showed decreased ejection fraction (EF). Electrophysiologic examination showed sinus node dysfunction in 21%. AV nodal dysfunction in 14% and dual AV nodal pathway in 21%. Histopathologic examination by endomyocardial biopsy showed myocellular hypertrophy, degeneration of myocytes, interstitial fibrosis and endomyocardial thickness in 86%, 36%, 35% and 14%, respectively. Since idiopathic ventricular arrhythmias in pediatric age group included relatively high electrophysiologic and histopathologic abnormalities, which were suggestive of occult myocardial disease and might be the early stage of cardiomyopathy, careful follow-up should be required.

[Histopathological studies of endomyocardial biopsy on the children with Kawasaki disease].

Since there has been many reports on the coronary artery lesions in the patients with Kawasaki disease, but only a few reports on histopathological investigation employing endomyocardial biopsy, histopathological study was performed in eighteen children of Kawasaki disease with coronary artery lesions and eighteen children of Kawasaki disease with intact coronary artery, aged from one year and ten months to fourteen years. There were twenty males and sixteen females. Comparing Kawasaki disease who had coronary artery lesions with those not, there was no striking difference in histologic findings. Kawasaki disease without coronary artery lesions revealed myocellular hypertrophy, degeneration of myocytes, disarray, interstitial fibrosis and endocardial changes in 44%, 61%, 11% and 44%, respectively. Among Kawasaki disease who had coronary artery lesions, children with coronary artery stenosis showed a higher incidence of histological abnormalities than those with coronary artery aneurysm. Some cases of Kawasaki disease were recognized to have significant myocardial abnormalities even in three to six years after onset, which seemed to persist whether or not they would have coronary artery lesions. Since Kawasaki disease who would have myocardial damages might have the potential for developing cardiomyopathy, careful attention should be payed to myocardial lesions as well as sequelae of coronary artery lesions.

Hyperthermic intraperitoneal chemotherapy using a combination of mitomycin C,5-fluorouracil, and oxaliplatin in patients at high risk of colorectal peritoneal metastasis: A Phase I clinical study.

INTRODUCTION: The drugs and protocols used for hyperthermic intraperitoneal chemotherapy (HIPEC) vary among institutions. Here we show the efficacy of the 3-drug combination of mitomycin C (MMC), 5-fluorouracil (5FU), and oxaliplatin (OHP) in an in vitro simulation of HIPEC and the safety of HIPEC with these drugs during a Phase I study of patients at high risk of developing colorectal peritoneal metastasis. METHODS: To simulate HIPEC, we used HCT116 and WiDr cells to assess the growth inhibitory efficacy of MMC 2 µg/mL, 5FU 200 µg/mL, and OHP 40 µg/mL as single drugs or their combination after an exposure time of 30 min at 37 or 42 °C. In addition, nine patients underwent surgical resection of tumors and HIPEC with MMC, 5FU, and an escalating dose of OHP (90/110/130 mg/m²). Dose-limiting toxicity was monitored. RESULTS: In the simulation, the 3-drug combination showed marked tumor-suppressive effects compared with those from ten times higher dose of OHP 400 µg/mL, with significant augmentation under hyperthermic conditions. No dose-limiting toxicity occurred in the clinical study. Dose escalation was completed at the final level of OHP. CONCLUSIONS: The MMC-5FU-OHP combination showed marked growth inhibition against colorectal cancer cells under hyperthermic conditions in vitro. In the phase I study, the recommended dose of OHP was determined as 130 mg/m² when used with MMC and 5FU; HIPEC using MMC-5FU-OHP appears to be safe and feasible for patients at high risk of colorectal peritoneal metastasis.

Potential high virulence for infective endocarditis in Streptococcus mutans strains with collagen-binding proteins but lacking PA expression.

OBJECTIVE: Streptococcus mutans, an aetiologic agent of dental caries, is a pathogen for infective endocarditis (IE). We investigated strains that express collagen-binding proteins (CBPs) with further classification based on expression of the 190-kDa protein antigen (PA). METHOD: Zeta-potential values of strains TW871 (CBP+/PA+) and MT8148 (CBP-/PA+), and their respective PA-defective mutant strains TW871PD (CBP+/PA-) and MT8148PD (CBP-/PA-), were analysed, as were their adhesion to and invasion of human umbilical vein endothelial cells (HUVECs). The distribution of strains from the oral cavities of 200 healthy individuals was analysed for CBP and/or PA expression and the strains were characterised for their adhesion and invasion properties. RESULTS: TW871PD and MT8148PD showed significantly lower zeta-potential values than TW871 and MT8148, respectively. Collagen-binding rates were significantly higher for TW871PD than for TW871 but nearly negligible for MT8148 and MT8148PD. The adhesion and invasion rates of HUVECs were significantly higher for TW871PD than for TW871 and significantly higher for TW871 than for MT8148 and MT8148PD. The prevalence of CBP+ strains was ~10% and ~3% in the case of CBP+/PA- strains. Analyses of 200 clinical strains showed the CBP+/PA- group to have higher adhesion and invasion rates than other groups. CONCLUSIONS: CBP+/PA- S. mutans strains, despite their low distribution frequency, may be highly virulent for infective endocarditis.