Helicobacter pylori stimulates inducible nitric oxide synthase expression and activity in a murine macrophage cell line

BACKGROUND & AIMS: Helicobacter pylori uniquely colonizes the human stomach and produces gastric mucosal inflammation. High-output nitric oxide production by inducible nitric oxide synthase (iNOS) is associated with immune activation and tissue injury. Because mononuclear cells comprise a major part of the cellular inflammatory response to H. pylori infection, the ability of H. pylori to induce iNOS in macrophages was assessed. METHODS: H. pylori preparations were added to RAW 264.7 murine macrophages, and iNOS expression was assessed by Northern blot analysis, enzyme activity assay, and NO2- release. RESULTS: Both whole H. pylori and French press lysates induced concentration-dependent NO2- production, with peak levels 20-fold above control. These findings were paralleled by marked increases in iNOS messenger RNA and enzyme activity levels. iNOS expression was synergistically increased with interferon gamma, indicating that the H. pylori effect can be amplified by other macrophage-activating factors. Studies of lipopolysaccharide (LPS) content and polymyxin B inhibition of LPS suggested that the H. pylori effect was attributable to both LPS- dependent and -independent mechanisms. CONCLUSIONS: iNOS expression in macrophages is activated by highly stable H. pylori products and may play an important role in the pathogenesis of H. pylori-associated gastric mucosal disease. (Gastroenterology 1996 Dec;111(6):1524-33)     

Developmental programming by high fructose decreases phosphorylation efficiency in aging offspring brain mitochondria,correlating with enhanced UCP5 expression

Fructose has recently been observed to affect brain metabolism and cognitive function in adults. Yet, possible late-onset effects by gestational fructose exposure have not been examined. We evaluated mitochondrial function in the brain of aging (15 months) male offspring of Fischer F344 rat dams fed a high-fructose diet (50% energy from fructose) during gestation and lactation. Maternal fructose exposure caused a significantly lower body weight of the offspring throughout life after weaning, while birth weight, litter size, and body fat percentage were unaffected. Isolated brain mitochondria displayed a significantly increased state 3 respiration of 8%, with the substrate combinations malate/pyruvate, malate/pyruvate/succinate, and malate/pyruvate/succinate/rotenone, as well as a significant decrease in the P/O₂ ratio, compared with the control. Uncoupling protein 5 (UCP5) protein levels increased in the fructose group compared with the control (P=0.03) and both UCP5 mRNA and protein levels were inversely correlated with the P/O₂ ratio (P=0.008 and 0.03, respectively), suggesting that UCP5 may have a role in the observed decreased phosphorylation efficiency. In conclusion, maternal high-fructose diet during gestation and lactation has long-term effects (fetal programming) on brain mitochondrial function in aging rats, which appears to be linked to an increase in UCP5 protein levels.     

Clinical significance of incidental findings on staging positron emission tomography for oesophagogastric malignancies

Introduction

The aim of this retrospective study was to determine the clinical significance of incidental findings detected on positron emission tomography (PET) in patients undergoing staging of oesophagogastric malignancies.

Methods

Patients with oesophagogastric malignancies who underwent PET between June 2007 and May 2012 were included in the study. PET was performed according to hospital protocol. All imaging was interpreted by two consultant radiologists in nuclear medicine. Incidental findings that were unrelated to the primary malignancy were recorded and patients were recommended to have further investigations (imaging, endoscopy and biopsy).

Results

Overall, 333 patients (240 male, 93 female; mean age: 67 years) with upper gastrointestinal malignancies were eligible for inclusion in the study. Eighty-nine of these patients had PET demonstrating one or more incidental findings. Two patients were found to have a second primary malignancy. One patient had a distant metastasis of his primary cancer and six patients had a premalignant lesion.

Conclusions

In this study, incidental findings were discovered in 26.7% of patients with known oesophagogastric cancer. A second primary cancer or premalignant lesion was found in 8.4% of patients with incidental findings. Patients with these findings should be investigated to rule out further malignancy. There were a high proportion of false positive results in our study. It is recommended that each patient is considered on an individual basis and assessed with simultaneous PET and computed tomography.     

Effect of common polymorphisms of the farnesoid X receptor and bile acid transporters on the pharmacokinetics of ursodeoxycholic acid

Ursodeoxycholic acid (UDCA), a natural, dihydroxy bile acid, promotes gallstone dissolution and has been attributed with several other beneficial effects. The farnesoid X receptor (FXR) may influence the pharmacokinetics of UDCA by modulating the expression of bile acid transporters. This exploratory study examined whether common functional polymorphisms in FXR and in bile acid transporter genes affect the pharmacokinetics of exogenous UDCA. Polymorphisms in genes for transporters involved in bile acid transport, solute carrier organic anion 1B1 (SLCO1B1) 388A>G and 521T>C, solute carrier 10A1 (SLC10A1) 800 C>T and ATP‐binding cassette B11 (ABCB11) 1331T>C, and the FXR ‐1G>T polymorphism were genotyped in 26 male Chinese subjects who ingested single oral 500‐mg doses of UDCA. Plasma concentrations of UDCA and its major conjugate metabolite glycoursodeoxycholic acid (GUDCA) were determined. The mean systemic exposure of UDCA was higher in the five subjects with one copy of the FXR ‐1G>T variant allele than in those homozygous for the wild‐type allele (n = 21) (AUC_0–24 h: 38.5 ± 28.2 vs. 20.9 ± 8.0 μg h/mL, P = 0.021), but this difference appeared mainly due to one outlier with the ‐1GT genotype and elevated baseline and post‐treatment UDCA concentrations. After excluding the outlier, body weight was the only factor associated with plasma concentrations of UDCA and there were no significant associations with the other polymorphisms examined. None of the polymorphisms affected the pharmacokinetics of GUDCA. This study showed that the common polymorphisms in bile acid transporters had no significant effect on the pharmacokinetics of exogenous UDCA but an effect of the FXR polymorphism cannot be excluded.     

Transgenic mice expressing human sickle hemoglobin are partially resistant to rodent malaria

The polymorphic frequency of the gene for beta s-globin involved in the generation of sickle trait and sickle cell anemia in the human population is caused by the enhanced resistance of sickle trait individuals to Plasmodium falciparum malaria, as supported by epidemiologic and in vitro studies. However, the mechanism for the protective effect of sickle hemoglobin in vivo has not been fully defined. The generation of transgenic mice expressing high levels of human beta s- and alpha-chains has allowed us to study this phenomenon in vivo in an experimental model. We infected the transgenic beta s mice with two species of rodent malaria and found a diminished and delayed increase in parasitemia as compared with controls. This is in contrast to our previous studies involving the introduction of a beta A transgene, which does not alter the infection. The use of this model allowed us to address the question of the mechanism of protection against malaria in mice expressing sickle hemoglobin. We find that splenectomy of transgenic mice completely reverses the protection against Plasmodium chabaudi adami infection. The results reported have shown a relationship between the presence of the beta s gene product and partial resistance to malaria in an experimental model in vivo and shows that the spleen plays an important role in this protection.     

Quantitative competitive PCR as a technique for exploring flea-Yersina pestis dynamics

We used a quantitative competitive polymerase chain reaction assay to quantify Yersinia pestis loads in fleas and bacteremia levels in mice that were used as sources of infectious blood meals for feeding the fleas. Xenopsylla cheopis, the Oriental rat flea, achieved higher infection rates, developed greater bacterial loads, and became infectious more rapidly than Oropsylla montana, a ground squirrel flea. Both flea species required about 10(6) Y. pestis cells per flea to be able to transmit to mice. Most fleas that achieved these levels, however, were incapable of transmitting. Our results suggest that at the time of flea feeding, host blood must contain > or = 10(6) bacteria/ml to result in detectable Y. pestis infections in these fleas, and > or = 10(7) bacteria/mL to cause infection levels sufficient for both species to eventually become capable of transmitting Y. pestis to uninfected mice. Yersinia pestis colonies primarily developed in the midguts of O. montana, whereas infections in X. cheopis often developed simultaneously in the proventriculus and the midgut. These findings were visually confirmed by infecting fleas with a strain of Y. pestis that had been transformed with the green fluorescent protein gene.     

Recombinant human stem cell factor enhances myeloid colony growth from human peripheral blood progenitors

Peripheral blood hematopoietic progenitors (PBHP) are capable of colony growth in vitro. The effect of stem cell factor (SCF), interleukin-6 (IL-6), and basic fibroblast growth factor (bFGF) on myeloid colony proliferation of PBHP was determined. PBHP purified by positive selection with CD34-specific antibody were plated in semisolid agarose with reported plateau doses of interleukin-3 (IL-3), granulocyte- macrophage colony-stimulating factor (GM-CSF), and granulocyte colony- stimulating factor (G-CSF) to enhance myeloid colony growth. Experiments then were done to examine colony growth in response to SCF or with SCF and bFGF and/or IL6. SCF alone in the absence of any other growth factors did not support colony growth. SCF at a determined optimum concentration of 100 ng/mL added to the combination of IL-3, GM- CSF, and G-CSF enhanced colony growth and size relative to proliferation in response to the latter three factors alone (from 78 to 188 total colonies/10(4) PBHP plated and from 10 to 93 large [> 200 cells] colonies/10(4) PBHP plated). Furthermore, addition of bFGF and/or IL-6 to the combination of optimum concentrations of SCF, IL-3, GM-CSF, and G-CSF further enhanced colony number and size in a dose- dependent fashion. Using the optimum combination of all growth factors, we determined that the number of myeloid colony-forming PBHP in whole blood was similar between individuals at about three colonies per milliliter whole blood. We conclude that progenitors capable of responding to the early-acting growth factor, SCF, are represented in PBHP and that the number of circulating myeloid colony-forming PBHP is likely a regulated parameter that may have an important biologic function.     

Sleep apnoea caused by rheumatoid arthritis

Sleep apnoea syndrome (SAS) is a rarely documented, but possibly lethal, complication of the instability of the cervical spine in rheumatoid arthritis. Five patients with SAS of a central or peripheral origin are presented, and the problems of recognizing and diagnosing the syndrome are discussed. We hope that clinicians will become more aware of the existence and the different aetiologies of SAS, thus improving early recognition and appropriate treatment. Adequate treatment has proven to increase survival in peripheral SAS and seems to be successful in doing so in central SAS.