Cribado del carcinoma escamoso de esófago en población de riesgo

Together with adenocarcinoma, epidermoid esophageal carcinoma is the most clinically important neoplasm of the esophagus. Because of the low incidence of epidermoid esophageal carcinoma in the general population, strategies for its early diagnosis are not a priority compared with other neoplasms. However, because survival is low when the disease is diagnosed in symptomatic patients (less than 20% at 5 years), methods for its early diagnosis should be investigated. The use of cytology or Lugol chromoendoscopy in countries with a high incidence of epidermoid carcinoma or in individuals at increased risk (mainly alcoholics and smokers) has allowed early diagnosis and potentially curative treatment, substantially increasing life expectancy in this group of patients. These results should stimulate the evaluation and eventual implementation of programs to achieve early diagnosis and therefore greater survival in patients with epidermoid esophageal carcinoma in Western countries.

[Appropriateness of indications for upper gastrointestinal endoscopy in open-access endoscopy units]

INTRODUCTION

The indication for upper gastrointestinal endoscopy (UGE) by the general practitioner may significantly reduce the waiting time list for the exploration and accelerates the process of taking decisions in patients with upper gastrointestinal pathology. The objective of this study is to compare the appropriateness of indications for diagnostic UGE between general practitioners and gastroenterologists in open-access endoscopy units.

PATIENTS AND METHODS

General practitioners were previously updated on the main indications, risks and benefits for UGE, and instructions for submitting patients to open-access units were given. The indications for UGE were analysed by means of the ASGE 1997 and EPAGE guidelines for the appropriate use of upper gastrointestinal endoscopy.

RESULTS

There were no statistical differences between patients referred by general practitioners or gastroenterologists with respect to gender, age, indication of UGE or the presence of alarm symptoms. According to the ASGE guidelines overuse of UGE was observed in 25 (18.4%) of 136 patients submitted by general practitioners and in 32 (18.6%) of 172 patients submitted by gastroenterologists (NS). According to the EPAGE guidelines a non-appropriated UGE was present in 16 (11.8%) of patients referred by general practitioners and by 19 (11%) of patients submitted by gastroenterologists (NS).

CONCLUSION

The level of appropriateness for UGE indication obtained by general practitioners is similar to that reached by gastroenterologists. This finding should be considered for the implementation of open-access endoscopy units in our country.

Genotipo y expresión fenotípica de la hemocromatosis hereditaria en España

INTRODUCTION

The prevalence of C282Y homozygosity in patients with hereditary hemochromatosis (HH) has been reported to be markedly lower in the Mediterranean Basin than in northern Europe. In Spain, the available data are contradictory and limited to small series in specific regions. The objective of this study is to determine the prevalence of the 2 main HFE gene mutations in a large series of unrelated Spanish patients with HH from different geographical origins.

PATIENTS AND METHOD

The criteria for HH diagnosis were: repeat serum transferrin saturation index (> 45% plus C282Y homozygosity and/or hepatic iron index (> 1.9 of dry liver weight in non-cirrhotic patients or (> 4.1 in patients with liver cirrhosis. Cases in related individuals were excluded. Demographic data, clinical expression, iron parameters and HFE gene mutations (C282Y and H63D) were assessed in 222 patients.

RESULTS

A total of 83.3% of patients were C282Y homozygous and 5% were compound heterozygous (C282Y/H63D). No significant differences in phenotypic expression or in the frequency of C282Y homozygosity were observed between patients born in the North and South of Spain.

CONCLUSION

The genotypic and phenotypic expression of HH in Spain is very similar to that reported in Northern Europe. Thus, the genetic heterogeneity described in some Southern European regions cannot be considered a common feature to all countries of the Mediterranean Basin.

Low frequency of upper gastrointestinal complications in a cohort of high-risk patients taking low-dose aspirin or NSAIDS and omeprazole

BACKGROUND

There is very little information available on the incidence of complications and on the best prevention therapy in high-risk patients taking non-steroidal anti-inflammatory drugs (NSAIDs) and/or aspirin. Randomized-controlled trials in such patients are rare for ethical reasons. We studied the incidence of gastrointestinal complications in high-risk patients taking long-term low-dose aspirin or non-aspirin-NSAIDs combined with omeprazole in a real-life clinical setting.

METHODS

This was a multicentre, prospective and observational study including 247 consecutive high-risk patients who had a clinical indication for long-term treatment with either low-dose aspirin or non-aspirin NSAIDs and omeprazole therapy. The occurrence of gastrointestinal complications was measured.

RESULTS

In addition to a recent history of peptic ulcer bleeding, all patients had at least 1 other risk factor and 112 (45.3%) had 3 or more risk factors; 78.9% were taking low-dose aspirin and the remainder non-aspirin NSAIDs. Mean follow-up was 14.6 +/- 10.38 months. Three patients taking low-dose aspirin developed upper gastrointestinal bleeding (1.2%; 95% CI 0.3-3.5; 1.0 event/100 patients/year). This was similar to the rate observed in studies involving non-high-risk patients taking low-dose aspirin and higher than that observed in patients not taking low-dose aspirin. Two additional patients developed a lower gastrointestinal bleeding event (0.81% (0.04%-3.12%); 0.67 events/100 patients/year), which was within the range expected in NSAID users.

CONCLUSIONS

The use of omeprazole in the high-risk patient taking low-dose aspirin or NSAIDs seems to be a safe therapeutic approach in this population and is associated with a low frequency of upper gastrointestinal complications.

Primary molars in severe infraocclusion: a retrospective study

The term severe infraocclusion is used to describe teeth located at the level of or below the alveolar crest and is rare.

AIM

The aims of the study were to evaluate the influence of age of diagnosis and treatment on the outcome of the successors of primary molars with severe infraocclusion and to propose a treatment protocol based on the age of diagnosis.

METHODS

A retrospective study of patients with primary molars in severe infraocclusion (PMSI) in the period 1987-2001 was carried out. Parameters assessed were age, sex, degree of infraocclusion based on radiographs, altered position of adjacent and successor teeth and treatment outcome.

RESULTS

The sample comprised 19 patients with 23 cases of PMSI, all were second primary molars (47.8% maxillary and 52.2% mandibular). Migration of the neighbouring tooth was present in 51.5% of cases. The PMSI treatment was by extraction in all cases, a space maintainer was fitted and remained in place until the eruption of the successor. The outcome was favourable in 82.6% of cases.

CONCLUSION

Successful treatment of PMSI depends on prompt diagnosis and appropriate treatment and follow-up of the cases. The earlier the age of detection, the more favourable the outcome.

[Helicobacter pylori and immunogenetic factors of the host: relevance of the HLADQA1 *0102 and *0301 alleles in peptic ulcer]

AIM

To investigate the potential contribution of the *0102 and *0301 alleles of the HLADQA1 gene in Helicobacter pylori infection and peptic ulcer disease in a Spanish Caucasian population.

PATIENTS AND METHODS

We studied 163 patients with peptic ulcer (117 duodenal ulcers and 46 gastric ulcers; 111 with recent upper gastrointestinal hemorrhage) and 90 controls. The *0102 and *0301 alleles of the HLADQA1 gene were typed by polymerase chain reaction using genomic DNA. H. pylori infection were determined by breath test and/or serology. The cytotoxins CagA and VacA were investigated using serology (Western-blot) in 98 patients and 48 controls with H. pylori infection.

RESULTS

H. pylori infection was found in 94.6% of patients with duodenal ulcer, in 84.4% of those with gastric ulcer and in 67.4% of controls (p < 0.001). The distribution of the *0102 allele of the HLADQA1 gene was similar in patients (31.9%) and in controls (36.7%). The *0301 was more frequent in patients with gastric ulcer (32.6%) than in those with duodenal ulcer (16.2%) (p < 0.05) but no differences were found on comparison with the control group (24.4%). No differences were found when the groups were analyzed according to H. pylori infection, CagA- and VacA-positive strains, consumption of non-steroidal antiinflammatory drugs or previous history of ulcer or hemorrhage.

CONCLUSION

The *0102 and *0301 alleles of the HLADQA1 gene did not alter susceptibility to H. pylori infection or the evolution of peptic ulcer disease in a Caucasian population in Spain.

Hereditary hemochromatosis in Spain

The C282Y mutation of the HFE gene has been reported as the main cause of hereditary hemochromatosis (HH). Another missense mutation (H63D) has also been detected at an increased frequency in a compound heterozygote state with the C282Y mutation in HH patients. However, these two mutations are not present in all of the HH patients, indicating that other mutations in the HFE gene, or in other loci, should exist. The present study reports the frequencies of the C282Y and H63D mutations in 74 Spanish HH patients and the results of the sequencing analysis of the HFE exons, intron-exon boundaries, and 588 bp of the 5' region in 5 patients negative for the C282Y mutation. We have detected a high frequency of the C282Y mutation (85.1%) in Spanish HH patients, indicating that this mutation is the most common defect associated with the disease in Spain. The screening of the HFE regions in our patients without the C282Y mutation has revealed the presence of five polymorphisms. However, no other pathological mutations have been found. Therefore, further efforts to characterize the unscreened part of the HFE gene or other loci should be taken to identify the potential genetic factors causing HH in the C282Y-negative patients.

Hyphomonas adhaerens sp. nov., Hyphomonas johnsonii sp. nov. and Hyphomonas rosenbergii sp. nov., marine budding and prosthecate bacteria

Three strains of prosthecate, budding bacteria, MHS-2T, MHS-3T and VP6T, were isolated from marine habitats including the open ocean (the pelagic zone), the offshore region (the neritic zone) and the hydrothermal vent region. A polyphasic approach including 16S rDNA sequencing, phenotypic analyses, serology, fatty acid analyses, membrane protein profiles and DNA-DNA hybridizations was used to place these strains in the genus Hyphomonas, a taxon of the alpha-Proteobacteria. The results of these analyses also showed that strains MHS-3T, MHS-2T and VP6T each represent a new species of Hyphomonas. The names Hyphomonas adhaerens (type strain MHS-3T, ATCC 43965T), Hyphomonas johnsonii (type strain MHS-2T, ATCC 43964T) and Hyphomonas rosenbergii (type strain VP6T, ATCC 43869T) are proposed for the new species. With these additions, Hyphomonas now contains eight species.

Gonadotrophin and testosterone suppression by 7alpha-methyl-19-nortestosterone acetate administered by subdermal implant to healthy men

The synthetic androgen 7alpha-methyl-19-nortestosterone (MENT) is a potent suppressor of gonadotrophin that has several advantages for long term administration to normal or hypoandrogenic men. The aim of this study was to examine MENT serum concentrations following subdermal insertion of MENT acetate (MENT Ac) implants and their effects on gonadotrophins, testosterone, dihydrotestosterone (DHT), sex hormone-binding globulin, prostate specific antigen and insulin-like growth factor-1 serum concentrations in normal men. A total of 45 healthy men were recruited at three clinics. Each subject received one, two or four implants for 28 days. Serum samples were obtained before insertion and on days 8, 15, 22, 29, 36 and 43 after implant insertion. The average daily dose delivered in vivo by one implant was approximately 500 microg. One, two or four MENT Ac implants produced dose dependent and sustained serum MENT concentrations for the entire duration of treatment of 0.7 +/- 0.1, 1.2 +/- 0.1 and 2.0 +/- 0.1 nmol/l respectively. This treatment induced a dose dependent decrease in gonadotrophin and androgen serum levels. Two and four implants induced maximal suppression that was maintained throughout treatment and was completely reversed after removal of the implants. The mean decreases were 93 +/- 1% for testosterone, 80 +/- 3% for DHT, 97 +/- 1% for luteinizing hormone and 95 +/- 1% for follicle stimulating hormone. No serious adverse reactions were reported by the volunteers and no consistent changes in clinical chemistry and haematology were found. These results indicate that MENT Ac implants are an efficient way of MENT administration and confirm the potent gonadotrophin and androgen suppressive effect of this drug.

Radiocesium accumulation in edible wild mushrooms from coniferous forests around the Nuclear Centre of Mexico

Cs-137 and K-40 have been determined in soil samples and in wild edible mushrooms from a forest ecosystem located at the Nuclear Centre of Mexico (NCM) and in several surrounding localities. The transfer factors for Cs-137 were studied in 21 mushroom species from 1993 to 1997. The Cs-137 and K-40 determinations were performed using a gamma spectrometer system of low level counting with a high purity germanium (HPGe) detector. The local mushroom species that were found to show higher Cs-137 transfer factors were Clavariadelphus truncatus, Cortinarius caerulescens, Gomphus floccosus and Lyophyllum decastes. The Cs-137 levels obtained at the NCM in some mushroom samples were slightly lower than those from surrounding localities indicating that the nuclear facility has not emitted Cs-137 to the atmosphere.

Gastric mucosal blood flow regulation in response to different stimuli

We compared changes in gastric mucosal blood flow (GMBF) and left gastric artery blood flow (LGABF) in response to pharmacological, physiological, and pathological stimuli. GMBF and LGABF were measured by the hydrogen gas clearance and perivascular ultrasonic transit time techniques, respectively, under baseline conditions and following intravenous infusion of vasopressin or pentagastrin, isovolemic hemodilution, or gastric perfusion with HCl-taurocholate. Blood flow changes following vasopressin or hemodilution were significantly larger in the left gastric artery than in the gastric mucosa. In contrast, the increment in blood flow associated with pentagastrin-stimulated acid secretion was significantly greater in the gastric mucosa than in the extramural artery. Barrier disruption with acid-taurocholate induced similar changes in both measurement sites. The gastric hyperemia induced by either mechanism was significantly attenuated by blockade of NO synthesis. These data demonstrate that although functional changes in GMBF are primarily supported by changes in blood flow at the extramural gastric arteries, the gastric mucosal microvasculature is also under the influence of independent local control mechanisms.

Constitutive NOS isoforms account for gastric mucosal NO overproduction in uremic rats

To study whether renal failure enhances gastric mucosal nitric oxide (NO) formation in the rat, we measured 1) in vivo NO concentration and 2) NO synthase (NOS) activity, content, and mRNA expression in gastric mucosal homogenates of uremic and sham-operated anesthetized rats. Gastric mucosal NO release was measured by an electrochemical technique. NOS content was analyzed by Western immunoblots, using specific monoclonal antibodies. Constitutive (Ca2+ dependent; cNOS) and inducible (Ca2+ independent; iNOS) NOS activities were assayed by following the conversion of L-[U-14C]arginine to [U-14C]citrulline. mRNA expression for the constitutive neuronal (ncNOS), endothelial (ecNOS), and iNOS isoforms was determined by reverse transcription-polymerase chain reaction. Under basal conditions, gastric mucosal NO concentration was significantly greater in uremic compared with control rats. This was accompanied by significantly greater gastric mucosal cNOS activity in uremic rats than in control rats, whereas no differences were observed in iNOS activity between both groups of animals. Moreover, total enzyme content and the levels of gastric mucosal mRNA expression for ncNOS, ecNOS, and iNOS showed no significant differences between uremic and sham-operated rats. These data confirm that, in uremic rats, enhanced Ca2+-dependent NOS activity is responsible for gastric mucosal NO overproduction and suggest that the main regulatory mechanism is not transcriptional but translational and/or posttranslational in nature.

Structure, function and immunochemistry of bacterial exopolysaccharides

There has been much written on bacterial exopolysaccharides (EPS) and their role in virulence. Less has been published regarding EPS in free living species. This review focuses on that subject, emphasizing their functions in the environment and the use of antibody probes to study them.

Gastrin mediates the increase in gastric cell growth in uremic rats

In a rat model of chronic renal failure, we recently reported that hypergastrinemia was associated with increased stomach weight and parietal cell and enterochromaffin-like (ECL) cell density. In this study, the role of gastrin in mediating trophic effects of uremia on the gastric mucosa was examined by chronic immunoneutralization of endogenous gastrin in the sub-total nephrectomy uremic rat model. Three weeks after surgery, the rats were uremic (azotemic and hypertensive). Uremic rats had a significant increase in corpus mucosal height (17%), parietal cell density (14%), ECL cell density (27%), and basal gastric mucosal blood flow (63%). These effects were specifically inhibited by chronic administration of gastrin-specific monoclonal antibody (5 mg ip every other day) in the 3-wk postoperative period. Uremic rats also had an increase in stomach weight (23%), corpus mucosal area (8%), arterial blood pressure, and serum creatinine and a decrease in body weight. Gastrin immunoneutralization did not alter these effects. The findings suggest that elevated levels of endogenous circulating gastrin in uremic rats mediate, in part, the trophic response observed in the gastric mucosa.

Gastric emptying of solids but not liquids is decreased in rats with chronic renal failure

Severe gastric complications occur in uremic patients, yet few studies have addressed the effect of chronic renal failure (RF) on gastric physiology. In the present study, we investigated: (1) the effect of RF on gastric emptying of liquids and solids in awake rats, (2) the motor function in the gastric corpus, and (3) the role of nitric oxide in any alterations in gastric motor function in uremic rats. RF was induced by partial kidney infarction. RF had no effect on gastric emptying of liquids but significantly inhibited gastric emptying of solids by 68%. N-Nitro-L-arginine, an inhibitor of nitric oxide (NO) synthesis, had no effect on the reduced gastric emptying of solids in RF rats. RF rats showed an altered pattern of gastric motility compared to sham-operated rats. These data suggest that RF induced an inhibition of gastric emptying of solids, but not liquids. However, NO does not seem to play a role in this inhibition.

Prostaglandin E2 enhances gastric defense mechanisms against acid injury in uremic rats

BACKGROUND/AIMS

Uremia increases gastric mucosal H+ permeability and acid back-diffusion-related injury in rats. The aim of this study was to examine the effect of the synthetic gastroprotective compound 16,16-dimethyl prostaglandin E2 (16,16-dm PGE2) on the gastric barrier to acid injury in uremic rats.

METHODS

Chronic renal failure was induced by subtotal nephrectomy. Acid back-diffusion injury was induced by superfusion with 15% ethanol in 0.15N HCl and was assessed by image analysis. Intracellular pH, initial surface cell acidification rate, and thickness of mucous gel layer were measured with in vivo microscopy. Gastric mucosal blood flow was measured in separate experiments by laser-Doppler flowmetry.

RESULTS

Pretreatment with 16,16-dm PGE2 attenuated H+ back-diffusion and prevented the production of gross lesions. 16,16-dm PGE2 increased gastric mucous gel thickness, decreased initial acidification rate, and maintained intracellular pH homeostasis during exposure to luminal acid. Gastric mucosal blood flow was not changed during superfusion with a neutral buffer but increased during acid exposure in rats treated with 16,16-dm PGE2.

CONCLUSIONS

16,16-dm PGE2 attenuated H+ back-diffusion injury in uremic rats. This effect was associated with blunting of the initial decrease of intracellular pH and enhanced surface cell intracellular pH homeostasis during acid exposure. These effects were associated with an increased mucous gel layer thickness and an acid-related increase in blood flow.

Uremia in the rat affects gastric cell growth and differentiation

The aim of this study was to determine if hypertrophy of different tissues seen in uremic rats included gastrointestinal hypertrophy and an increase in parietal cell mass that might explain the increased acid secretion we previously reported. Chronic renal failure was induced by subtotal nephrectomy. Despite a lower total body weight, uremic rats had a significantly greater stomach weight (33%), corpus area (13%), corpus mucosal height (19%), and parietal (32%) and enterochromaffin-like (ECL, 54%) cell density, but a 16% decrease in mucous neck cell region height. These findings suggest that uremia leads to gastric stem cell stimulation with differentiation favoring parietal and ECL cells over mucous cells. In addition, in uremic rats there was an increase in height of the duodenal mucosa, but not of the ileal or transverse colon mucosa. In conclusion, the present study shows that uremia in the rat promotes hypertrophy of the stomach with cell differentiation favoring parietal cells over mucus cells. The increase in parietal cell mass may explain the increased acid secretion in these rats.

Delayed gastric emptying induced by inhibitors of nitric oxide synthase in rats

The effect of the nitric oxide (NO) synthase inhibitor, NG-nitro-L-arginine methyl ester, on gastric emptying of a non-nutrient solution was investigated in conscious rats. NG-Monomethyl-L-arginine (10 mg/kg i.v.) and NG-nitro-L-arginine methyl ester (3 or 10 mg/kg i.v.) inhibited the 20-min rate of gastric emptying of liquids by 34%, 69% and 84% respectively, whereas the 0.3 mg/kg of NG-nitro-L-arginine methyl ester or 3 mg/kg of NG-monomethyl-L-arginine had no effect. The inhibitory effect of NG-nitro-L-arginine methyl ester (3 mg/kg) was prevented by L-arginine (300 mg/kg i.v.), but not by D-arginine (300 mg/kg i.v.). NG-Nitro-L-arginine methyl ester (0.3-10 mg/kg) induced a dose-related increase in mean blood pressure up to 161 +/- 10 mm Hg. Spontaneous hypertensive rats with a mean blood pressure of 180 +/- 5 mm Hg had a gastric emptying rate of 51.9 +/- 6.1%. These data indicate that NO synthase inhibitors given i.v. at doses that inhibit NO synthase, delay gastric emptying through mechanisms which are unrelated to changes in arterial blood pressure.

Uremia increases gastric mucosal permeability and acid back-diffusion injury in the rat

The possibility that chronic uremia renders the gastric mucosa more susceptible to acid injury was investigated. A rat model of chronic renal failure was induced by subtotal nephrectomy. [H+] back-diffusion across the mucosa, following intragastric perfusion of 0.15N HCl or 15% ethanol in 0.15N HCl, was significantly greater in uremic than in sham-operated rats. Gastric mucous gel thickness and transmural potential difference were significantly lower in rats with renal insufficiency. Furthermore, a significantly greater acidification rate of the surface epithelial cells was found in uremic rats than in sham-operated rats during superfusion with pH 1.7 buffer. Intragastric administration of acidified ethanol or aspirin solutions markedly increased gastric mucosal blood flow (68% and 89% respectively) in the sham-operated group producing mild injury, in contrast to uremic rats, where a lesser increase in mucosal blood flow (7% and 14% respectively) was associated with more pronounced mucosal injury. It was concluded that enhanced susceptibility to acid injury in uremia is due to a reduction of function of pre-epithelial, epithelial, and postepithelial elements of the gastric mucosal barrier.

Nitric oxide-mediated gastric hyperemia decreases ethanol-induced gastric mucosal injury in uremic rats

We investigated whether the recently described endothelium-derived nitric oxide-mediated gastric hyperemia in the uremic rat protects the gastric mucosa against ethanol injury. Uremia was induced by subtotal nephrectomy. Basal gastric mucosal blood flow, measured by a hydrogen gas clearance technique, was significantly higher in uremic than control rats. Continuous intragastric perfusion with 40% ethanol produced significantly less gross and histological lesions in uremic than in control rats. The administration of 3 mg/kg of NW-nitro-L-arginine methyl ester, a specific inhibitor of nitric oxide biosynthesis, decreased resting gastric mucosal blood flow to control levels in uremic rats, but had no effect on basal gastric blood flow in control rats. This pretreatment with the inhibitor of nitric oxide biosynthesis increased 40% ethanol-induced gastric mucosal lesions in uremic rats to the same level as that observed in control rats, but had no effect on lesions in control rats. In conclusion, this study suggests that in the uremic rat, gastric hyperemia, mediated by increased endothelium-derived nitric oxide, attenuates ethanol-induced gastric mucosal injury.