Gene expression in gastric biopsies from patients infected with Helicobacter pylori.

BACKGROUND: Helicobacter pylori infection has protean effects on gene expression in the host gastric mucosa, which have been investigated by gene chip analysis in vitro. In this study the effects of H. pylori infection on host gene expression in the gastric antral mucosa in patients were examined. METHODS: One gastric antral biopsy was obtained from a total of 18 untreated patients undergoing routine endoscopic evaluation of chronic abdominal complaints. Nine patients had histologic evidence of H. pylori infection and 9 age- and sex-matched patients had no histologic evidence of H. pylori infection. A microarray analysis was performed using a gene chip containing 35,000 human expressed sequence tags on RNA extracted from endoscopic, gastric antral biopsies, and average gene expression among infected and uninfected patients was compared. RESULTS: Underexpressed genes in infected patients' mucosa included gastric intrinsic factor and several metallothionein isoforms. Overexpressed genes in infected patients' mucosa comprised MHC Class II molecules, immunoglobulin and B-cell activation genes, as well as genes known to induce apoptosis. Changes in expression were confirmed for a subset of genes by SYBR green real-time PCR. CONCLUSIONS: Microarray analysis of antral biopsies from patients with and without H. pylori infection revealed differential expression of metal regulatory, immunity and inflammation-related genes.

Use of infliximab in pediatric patients with inflammatory bowel disease.

BACKGROUND: The concentration of tumor necrosis factor, a proinflammatory cytokine, is increased in the gastrointestinal mucosa of patents with active Crohn's disease (CD) and ulcerative colitis (UC). Neutralization of tumor necrosis factor decreases the mucosal inflammatory response of adults with CD. Little information is available on the use of monoclonal antibody to tumor necrosis factor (infliximab) in children and adolescents with CD or UC. OBJECTIVE: To evaluate the clinical response and side effects of patients to infliximab. METHODS: A retrospective review of data regarding 18 pediatric and adolescent patients with active CD (n = 15) and UC (n = 3) poorly controlled with conventional therapy. All patients received one to six intravenous infusions of infliximab 5 mg/kg, while receiving their usual medications. RESULTS: All patients experienced clinical improvement, including decrease in the frequency of stooling and resolution of extraintestinal symptoms such as arthropathy, malaise, and skin manifestations after treatment with infliximab. All but one patient had a documented decrease in the erythrocyte sedimentation rate. Prednisone dosage was tapered in all but two patients, and discontinued in seven patients. Intravenous infusion of infliximab was well tolerated. One patient developed a rash several days after the infusion. A patient who received six infliximab infusions developed recurrent Staphylococcus aureus infections, as well as septic arthritis and chronic osteomyelitis during the follow-up period, raising the issue of the long-term safety of infliximab. CONCLUSIONS: Treatment of our patients with refractory CD and UC with infliximab was associated with remarkable clinical improvement. Although the drug may have an important role in their management, further assessment of long-term safety and efficacy is needed.

Syndrome of hypokalemic metabolic alkalosis and hypomagnesemia associated with gentamicin therapy: case reports.

Nephrotoxicity, as evidenced by renal insufficiency is a well-known consequence of gentamicin therapy. We report two patients with gentamicin-induced syndrome of hypokalemic metabolic alkalosis and hypomagnesemia. Both had complete recovery of renal tubular function after cessation of antibiotic therapy. These cases emphasize the need to routinely monitor patients receiving gentamicin therapy for electrolyte abnormalities to avoid potential morbidity.

Localization of inducible nitric oxide synthase mRNA in inflamed gastrointestinal mucosa by in situ reverse transcriptase-polymerase chain reaction.

Immunohistochemistry has been critical in determining the tissue localization of inducible nitric oxide synthase (iNOS). However, this technique suffers from nonspecific staining which may lead to false-positive results and the failure of antisera to recognize iNOS from different species. We developed a technique to determine the localization of iNOS mRNA, as opposed to protein, in tissue sections using an in situ RT-PCR (IS RT-PCR) technique. Sections of inflamed gastrointestinal mucosa were used because they were known to be positive for iNOS. The IS RT-PCR technique localized iNOS mRNA to the same sites as immunoreactive iNOS in human gastritis associated with Helicobacter pylori infection, Crohn's disease, and experimental inflammatory bowel disease induced by the hapten TNBS, in rat colon and in guinea pig ileum. The detection of mRNA had an excellent signal-to-noise ratio. Preservation of tissue morphology was poorer than that with immunohistochemistry due the cycles of heating required in the PCR process. This method could be very useful in detecting iNOS gene expression in situations of excessive nonspecific staining with immunohistochemistry or of failure of antibodies to react because of species differences. This technique is also readily applicable to detect RNA and DNA markers of other disease processes.

Gastroesophageal reflux and Nissen fundoplication following percutaneous endoscopic gastrostomy in children.

BACKGROUND: Abnormal gastroesophageal reflux after percutaneous endoscopic gastrostomy is a serious problem in neurologically impaired children. Protective fundoplication has been advocated. Whether esophageal pH monitoring before percutaneous endoscopic gastrostomy will predict later problems with gastroesophageal reflux is unclear. METHODS: Eighty-five mostly neurologically impaired pediatric patients who underwent percutaneous endoscopic gastrostomy were studied retrospectively regarding complications, success of nutritional rehabilitation, and the incidence of pathologic gastroesophageal reflux. Follow-up period was 1 to 4 years. Twenty-four-hour esophageal pH monitoring was performed in 46 patients before percutaneous endoscopic gastrostomy. RESULTS: There were no deaths. Two major complications occurred that required surgical intervention, and 14 minor complications occurred related to the procedure. Z-scores for weight increased significantly after percutaneous endoscopic gastrostomy. pH probe results were normal in 22 patients (group 1). Five required medical treatment for gastroesophageal reflux after percutaneous endoscopic gastrostomy, but only 1 (5%) later required Nissen fundoplication. pH probe results were abnormal in 24 patients (group 2). Nineteen required medical therapy for gastroesophageal reflux, and 7 (29%) later needed fundoplication (p < 0.05, incidence of fundoplication group 1 vs. group 2). Improvement in Z-scores was similar in patients requiring and not requiring fundoplication. CONCLUSIONS: Percutaneous endoscopic gastrostomy is a safe and effective technique for long-term nutritional support in children. Abnormal gastroesophageal reflux is common. Normal findings in an esophageal pH study before percutaneous endoscopic gastrostomy may be predictive of a favorable outcome with respect to gastroesophageal reflux. This is in contrast to patients with abnormal results in pH studies before percutaneous endoscopic gastrostomy of whom a relatively large percentage may later require fundoplication. Improved nutritional status after percutaneous endoscopic gastrostomy does not appear to have an impact on the severity of gastroesophageal reflux.

Genistein and gut inflammation: role of nitric oxide.

Genistein, a principal soy isoflavone, has been identified as a protein kinase inhibitor that possesses immunosuppressive and anti-inflammatory properties. The aim of the study was to determine if genistein modified chronic ileitis in guinea pigs induced by the hapten trinitrobenzene sulfonic acid (TNBS), and the activity index of cultured macrophages (RAW 264.7 cells) stimulated with lipopolysaccharide (LPS). Genistein at low doses (0.1 mg/kg, s.c.) had mild anti-inflammatory effects in TNBS ileitis. Therapeutic benefit included a reduction in nitric oxide production, granulocyte infiltration and improved mucosal architecture. Genistein, at low doses, also appeared to attenuate immunohistochemical staining for inducible nitric oxide synthase (iNOS) and nitrotyrosine. The beneficial effects of genistein were not apparent at doses above 0.1 mg/kg. We found that genistein also inhibited LPS-induced nitrite production by cultured macrophages and protected against LPS-induced necrosis despite its ability to cause apoptosis. These results indicate that genistein displayed mild anti-inflammatory properties which may, in part, involve an attenuation of nitric oxide release via inducible nitric oxide synthase, and the formation of peroxynitrite.

Antiinflammatory actions of cat's claw: the role of NF-kappaB.

BACKGROUND: Uncaria tomentosa is a vine commonly known as cat's claw or 'uña de gato' (UG) and is used in traditional Peruvian medicine for the treatment of a wide range of health problems, particularly digestive complaints and arthritis. PURPOSE: The aim of this study was to determine the proposed anti-inflammatory properties of cat's claw. Specifically: (i) does a bark extract of cat's claw protect against oxidant-induced stress in vitro, and (ii) to determine if UG modifies transcriptionally regulated events. METHODS: Cell death was determined in two cell lines, RAW 264.7 and HT29 in response to peroxynitrite (PN, 300 microM). Gene expression of inducible nitric oxide synthase (iNOS) in HT29 cells, direct effects on nitric oxide and peroxynitrite levels, and activation of NF-kappaB in RAW 264.7 cells as influenced by UG were assessed. Chronic intestinal inflammation was induced in rats with indomethacin (7.5 mg/kg), with UG administered orally in the drinking water (5 mg/mL). RESULTS: The administration of UG (100 microg/mL) attenuated (P < 0.05) peroxynitrite-induced apoptosis in HT29 (epithelial) and RAW 264.7 cells (macrophage). Cat's claw inhibited lipopolysaccharide-induced iNOS gene expression, nitrite formation, cell death and inhibited the activation of NF-kappaB. Cat's claw markedly attenuated indomethacin-enteritis as evident by reduced myeloperoxidase activity, morphometric damage and liver metallothionein expression. CONCLUSIONS: Cat's claw protects cells against oxidative stress and negated the activation of NF-kappaB. These studies provide a mechanistic evidence for the widely held belief that cat's claw is an effective anti-inflammatory agent.

Peroxynitrite-induced apoptosis in human intestinal epithelial cells is attenuated by mesalamine.

BACKGROUND & AIMS: Peroxynitrite (PN), a potent oxidant, has been implicated in the pathogenesis of gut inflammation and epithelial cell apoptosis. The aim of this study was to investigate mesalamine, a standard therapy for inflammatory bowel disease, to see if it attenuates PN-induced cytotoxicity in human intestinal epithelial cells and if mesalamine directly interacts with PN or its precursor, nitric oxide. METHODS: T84 and HT29 cells were divided in several protocols: mesalamine was administered 2 hours before, simultaneously, or 30 minutes after PN. T84 cells, grown in filter chamber inserts, were used to determine if basolateral or apical administration of PN initiated apoptosis and epithelial barrier function. The effects of mesalamine on PN decomposition and NO half-life were determined. RESULTS: Mesalamine resulted in a dose-dependent decrease in PN-induced apoptosis, whether mesalamine was administered before (>10 micromol/L; IC50, 16 micromol/L), simultaneously (25-200 micromol/L; IC50, 24 micromol/L), or 30 minutes (200 micromol/L) after PN exposure. Mesalamine protected the epithelial barrier function of T84 cells against PN. Mesalamine rapidly degraded PN, whereas the half-life of NO was not affected. CONCLUSIONS: The beneficial effects of mesalamine in the treatment of inflammatory bowel disease may involve an attenuation of PN-induced cell injury and apoptosis through direct and indirect mechanisms without affecting NO levels.

Inhibitors of nuclear factor kappa B cause apoptosis in cultured macrophages.

The precise role of the transcription factor nuclear factor kappa B (NF- kappaB) in the regulation of cell survival and cell death is still unresolved and may depend on cell type and position in the cell cycle. The aim of this study was to determine if three pharmacologic inhibitors of NF-kappaB, pyrrolidine dithiocarbamate, N-tosyl-L-lysl chloromethyl ketone and calpain I inhibitor, induce apoptosis in a murine macrophage cell line (RAW 264.7) at doses similar to those required for NF-kappaB inhibition. We found that each of the three inhibitors resulted in a dose- and time-dependent increase in morphologic indices of apoptosis in unstimulated, LPS-stimulated and TNF-stimulated cells. Lethal doses were consistent with those required for NF- kappaB inhibition. We conclude that nuclear NF-kappaB activation may represent an important survival mechanism in macrophages.

Peroxynitrite-induced apoptosis in T84 and RAW 264.7 cells: attenuation by L-ascorbic acid.

The free radicals nitric oxide and superoxide react to form peroxynitrite (ONOO-), a potent cytotoxic oxidant. This study was designed to evaluate whether addition of L-Ascorbic acid (AsC) into the culture medium decreases peroxynitrite-induced apoptosis in human intestinal epithelial (T84) and murine macrophage (RAW 264.7) cell lines. In Experiment 1, T84 and RAW 264.7 cells were divided in two protocols: (1) treated with 100-300 microM ONOO- and incubated for 4 h, and (2) treated with 10-100 microM ONOO- and incubated overnight (14 h). In Experiment 2, T84 and RAW 264.7 cells were treated with 300 microM ONOO- and 500 microM AsC and incubated for 4 h. In Experiment 3, T84 and RAW 264.7 cells were preincubated for 2 h with 500 microM AsC then exposed to 300 microM ONOO- for 4 h. Cell viability (necrosis) was assessed by trypan blue dye exclusion. Apoptosis was quantified with a cell death detection ELISA assay. In the 4 h protocol, ONOO- induced apoptosis in T84 and RAW 264.7 cells, at levels of 100-300 microM. Concentrations of ONOO- greater than 300 microM caused necrosis. In contrast, extension of the protocol to 14 h indicated that ONOO- induced apoptosis at lower concentrations (50;-75 microM), with concentrations > 75 microM resulting in necrosis. AsC administered to the media or with preincubation plus washout, decreased peroxynitrite-induced apoptosis in T84 and RAW 264.7 cells. These results indicate that ONOO- may contribute to the pathophysiology of gut inflammation by promoting cell death and ascorbic acid may protect against peroxynitrie-induced damage.

Nutrition and HIV infection in children.

HIV infection has profound effects on a patient's nutritional status because it can modulate appetite, nutrient absorption and basal metabolic rate. In addition, HIV infection can lead to the depletion of a variety of vitamins and micronutrients including vitamins A, D, B2, B6, B12, L-carnitine, iron, zinc and selenium. This review article summarizes existing data regarding nutritional defects in HIV-infected patients and the results of clinical studies addressing the effects of nutritional supplementation in infected patients.

Inducible nitric oxide synthase, nitrotyrosine, and apoptosis in Helicobacter pylori gastritis: effect of antibiotics and antioxidants.

Helicobacter pylori infection is a known risk factor for gastric cancer. We hypothesized that H. pylori infection would lead to the sustained production of the reactive nitrogen species nitric oxide and peroxynitrite as part of the host immune response. We further hypothesized that H. pylori infection would lead to increased apoptosis of gastric epithelial cells, possibly in response to free radical-mediated DNA damage. Using immunohistochemistry, we stained and scored gastric antral biopsies from 84 Colombian patients with nonatrophic gastritis before and after treatment for H. pylori infection. We examined expression of inducible nitric oxide synthase (iNOS); nitrotyrosine, a marker for peroxynitrite; and DNA fragmentation, a marker for apoptosis. Patients were treated with triple therapy (amoxicillin, 500 mg three times a day for 2 weeks; metronidazole, 400 mg three times a day for 2 weeks; and bismuth subsalicylate, 262 mg four times a day for 2 weeks, followed by 262 mg every day for 4-12 months). Eradication of H. pylori infection resulted in a significant reduction in iNOS and nitrotyrosine staining and a marginally significant reduction in apoptosis. Dietary supplementation with beta-carotene (30 mg every day for 4-12 months) resulted in a significant decrease in iNOS staining. Supplementation with ascorbic acid (1 g twice a day for 4-12 months) led to a significant reduction in nitrotyrosine staining. In patients supplemented with either ascorbic acid or beta-carotene, there was a trend toward a reduction in apoptosis, but this was not statistically significant. We conclude that H. pylori infection is accompanied by the formation of endogenous reactive nitrogen intermediates, which may contribute to DNA damage and apoptosis. In addition to antimicrobial therapy, dietary supplementation with beta-carotene and ascorbic acid may prevent the formation of these potential carcinogens.

Epidemiology of congenital heart disease in Louisiana: an association between race and sex and the prevalence of specific cardiac malformations.

We hypothesized that susceptibility to the genetic and environmental factors that disrupt cardiac development is associated with race and sex. To evaluate this hypothesis, we asked whether the prevalence of specific cardiac malformations differs by race and sex. We attempted to include all infants born alive in the State of Louisiana from January 1, 1988, through December 31, 1989, and diagnosed by echocardiography, catheterization and/or autopsy within a year of birth as having one of ten specific cardiac malformations. The prevalence of atrioventricular canal defects (AVCD) per 1,000 live births was significantly higher for black females (.744) compared to black males (.198) and for white females (.414) compared to white males (.116). Complete transposition of the great arteries (TGA) was significantly higher for white males (.559) compared to white females (.122); in contrast, TGA was not significantly different for black males (.198) and black females (.169). Obstructive left heart syndrome (OLHS)--aortic stenosis and/or coarctation of the aorta--was significantly higher for white males (.652) compared to white females (.317); in contrast, OLHS was not significantly different for black males (.264) and black females (.169). Single ventricle (SV) was significantly higher for whites (.202) compared to blacks (.067). We did not find that race and sex were associated with differences in the prevalence of tetralogy of Fallot and hypoplastic left heart syndrome. The numbers of infants with anomalous pulmonary venous return, tricuspid atresia, double outlet right ventricle, or truncus arteriosus were too small to measure an association with race and sex. These results demonstrate that the prevalence of a subset of cardiac malformations differs by race and sex.(ABSTRACT TRUNCATED AT 250 WORDS)