Time trends in risk and risk determinants of non-Hodgkin lymphoma in solid organ transplant recipients.

Organ transplantation increases risk of non-Hodgkin lymphoma (NHL), but long-term risk and time trends have seldom been evaluated. Immunosuppressive drug load is an important risk determinant, but the details are unclear. We studied NHL risk in a nationwide Swedish cohort of 11 081 graft recipients transplanted 1970-2008. Relative risks (RRs) were estimated within the cohort and versus the general population by age, sex, follow-up time and calendar period. NHL risk was also assessed by cumulative and average doses of immunosuppressive treatments in a nested case-control design throughout 1997 using conditional logistic regression. We observed 153 NHL cases during 97 853 years of follow-up. Compared with the general population, NHL risk was eightfold increased (RR 7.9; 95% confidence interval [CI] 6.6-9.4), and increased risks persisted after ≥15 years of follow-up among kidney (6.1; 95% CI 3.5-10) and nonkidney recipients (44; 14-103). Among nonkidney recipients, NHL risk was lower in the 2000s compared with the 1990s (0.5; 95% CI 0.3-1.0; p = 0.04). A high average dose of antithymocyte immunoglobulin (ATG) conferred an eightfold increased risk of NHL (OR 8.5; 95% CI 1.9-38). To conclude, posttransplant NHL risk decreased during the last decade among nonkidney recipients, possibly because of a more careful use of ATG, the introduction of new drugs, or both.

Pediatric organ transplantation and risk of premalignant and malignant tumors in Sweden.

Increased cancer risks are well documented in adult organ transplant recipients. However, the spectrum of malignancies and risk in the pediatric organ transplant population are less well described. We identified all solid organ transplanted patients aged <18 in Sweden between 1970-2007 (n = 536) in the National Patient Register and linked to the Cancer Register. Nationwide rates were used to calculate standardized incidence rate ratios and 95% CI estimating the association between transplant and cancer during maximum 36 years of follow-up. Nearly 7% of pediatric solid organ transplant recipients developed a premalignant or malignant tumor during follow-up. Transplantation was associated with an increased risk of any cancer (n = 24, SIR = 12.5, 95% CI: 8.0-18.6): non-Hodgkin lymphoma (NHL) (n = 13, SIR = 127, 95% CI: 68-217), renal cell (n = 3, SIR = 105, 95% CI: 22-307), vulva/vagina (n = 3, SIR = 665, 95% CI: 137-1934) and nonmelanoma skin cancers (n = 2, SIR = 64.7, 95% CI: 7.8-233.8). NHL typically appeared during childhood, while other tumors were diagnosed during adulthood. Apart from short-term attention toward the potential occurrence of NHL, our results suggest cancer surveillance into adulthood with special attention to skin, kidneys and the female genitalia.

Disappointment and drop-out rate after being allocated to control group in a smoking cessation trial.

BACKGROUND: If a patient agrees to take part in a randomised trial it is reasonable to presume that the patient would prefer to be allocated into the intervention. This study's aim was to investigate how patients react after they have been randomised into control group. METHODS: Nested study within two randomised trials. Telephone interviews with a structured questionnaire. The participants were invited after they had been randomised into the control group in two smoking cessation trials. The main outcome measures were reaction to control group allocation and drop-out rates. RESULTS: Twenty-seven out of 30 possible interviews were successfully completed. Fourteen persons expressed that they were disappointed of being allocated to the control group. Five persons said that they had not understood the consent information and three of these were very disappointed. Surprisingly these three persons said that they had not expected a randomization. A woman expressed that she "felt as if I was being swindled". There were in total 9/117 (7.7%) lost to follow-up in the control group and there were 4/105 (3.8%) losses to follow-up in the intervention group (P=0.26). Active withdrawal of consent was slightly higher among the control group, five in the control group (4.3%) and no active withdrawals in the intervention group (P=0.06). CONCLUSIONS: Disappointment was common after allocation to the control group. This is a probable explanation of the higher drop-out rate in the control group. The consent information is of highest importance since those who were very disappointed claimed they did not receive understandable information.

Role of surgeon-performed ultrasound on further management of patients with acute abdominal pain: a randomised controlled clinical trial.

BACKGROUND: The use of bedside ultrasound performed by the surgeon or emergency physician on duty at the emergency department is increasing. A study was performed which is the first randomised study to evaluate the benefits of surgeon-performed ultrasound for the management of the acute abdomen. METHODS: 800 patients who attended the emergency department at Stockholm South General Hospital, Sweden for abdominal pain were randomised either to receive or not receive surgeon-performed ultrasound as a complement to routine management. Outcome measures included the number of complementary investigations, time spent in the emergency department, admission rate, length of hospital stay if admitted, admission to surgery and timing of surgery if required. RESULTS: The number of complementary ultrasound examinations was considerably higher in the group who did not receive bedside ultrasound (18.8 percentage points difference, p<0.001). The admission rate was lower in the ultrasound group (7.2 percentage points difference, p = 0.041) and the proportion of patients requiring surgery submitted for surgery directly from the emergency department was higher in the ultrasound group (18.5 percentage points difference, p = 0.013). CONCLUSION: This study shows benefits in the management of the acute abdomen resulting in fewer further requested examinations, fewer admissions and shorter lead times to surgery. On the basis of these results, it is recommended for implementation in emergency departments. TRIAL REGISTRATION NUMBER: NCT00550511.

The efficacy of a smoking cessation programme in patients undergoing elective surgery: a randomised clinical trial.

It is known that smokers constitute an important risk group of patients undergoing surgery. It is unknown how smoking cessation intervention initiated 4 weeks prior to elective surgery affects the probability of permanent cessation. We randomly assigned 117 patients, scheduled to undergo elective orthopaedic and general surgery, to smoking cessation intervention and control group. The intervention group underwent a programme initiated, on average, 4 weeks prior to surgery with weekly meetings or telephone counselling and were provided with free nicotine replacement therapy (NRT). The control group received standard care. As a result, 20/55 (36%) patients the intervention group vs 1/62 (2%) in the control group became completely abstinent throughout the peri-operative period (p < 0.001). After 1 year, those in the intervention group was most likely to be abstinent (18/55 (33%) vs 9/62 (15%) of the controls (p = 0.03). Level of nicotine dependence and obesity seemed to be a predictor of long-term abstinence (p = 0.02).

Risk of subarachnoid haemorrhage according to number of affected relatives: a population based case-control study.

Relatives of patients with aneurysmal subarachnoid haemorrhage (SAH) have an increased risk of this type of stroke. In a population-based study, we analysed individualized risks of SAH according to the number of affected first-degree relatives. We retrieved all patients diagnosed with SAH in 2001-05 from the Swedish Inpatient Register. For each of the 5,282 patients, we identified five controls (n = 26,402) through the nationwide Register of Total Population. Through the Multi-generation Register, we retrieved all first-degree relatives for patients and controls and checked whether these 130,373 relatives had been diagnosed with SAH. By means of conditional logistic regression, we calculated odds ratios with corresponding 95% confidence intervals (95% CI) for the risk of SAH according to the number of affected relatives, and to the gender, age and type of kinship of the patient and affected relative. The odds ratio of SAH for individuals with one affected first-degree relative was 2.15 (95% CI 1.77-2.59). For individuals with two affected first-degree relatives, the odds ratio was 51.0 (95% CI 8.56-1117). Gender, age and type of kinship did not influence the risk for individuals with one or more affected relatives. The risk of SAH is slightly increased in the cases with one, but strongly increased in cases with two or more affected first-degree relatives. The latter strongly increased risk corresponds to a considerable absolute life-time risk of SAH and underscores the need to consider screening for aneurysms in these individuals.

Impact of surgeon-performed ultrasound on diagnosis of abdominal pain.

BACKGROUND: A randomised study was performed to evaluate the diagnostic accuracy of surgeon-performed ultrasound in the emergency department for patients presenting with abdominal pain. METHODS: Surgeons responsible for the examination of study patients underwent 4 weeks of ultrasound training. 800 patients who were attending the emergency department for abdominal pain were randomised to undergo or not undergo surgeon-performed ultrasound as a complement to standard examination. The preliminary diagnosis made by the surgeon, with or without ultrasound, was compared with the final diagnosis made by a senior surgeon 6-8 weeks later. RESULTS: Diagnostic accuracy was significantly higher in the group examined with ultrasound (64.7% vs 56.8%, p = 0.027). Ultrasound proved to be helpful in making or confirming a correct diagnosis in 24.1% of cases receiving ultrasound and to contribute in 2.9%. In 22.3% of patients the diagnosis of non-specific pain was confirmed by normal findings. Ultrasound was misleading in 10.2% of cases and had no influence on the diagnosis in 40.0%. CONCLUSION: For patients with acute abdominal pain, higher diagnostic accuracy is achieved when surgeons use ultrasound as a diagnostic complement to standard examination. The use of bedside ultrasound should be considered in emergency departments.

Impact of body mass index and tobacco smoking on outcome after open appendicectomy.

BACKGROUND: The effect of body mass index (BMI) and smoking on the risk of perforated appendix and postoperative complications in patients undergoing open appendicectomy for acute appendicitis was studied. METHODS: Record linkage was used to identify 6676 male construction workers who underwent open appendicectomy for acute appendicitis between 1971 and 2004. Multivariable binomial logistic regression analyses were performed. RESULTS: After adjustment for age, calendar period and BMI, smoking was significantly associated with an increased risk of perforated appendicitis (PA) (P = 0.004). The relative risk was 1.29 (95 per cent confidence interval 1.11 to 1.50) among current smokers with more than 10 pack-years of tobacco use. In patients with non-perforated appendicitis (NPA), the relative risk of overall postoperative complications was significantly associated with BMI (P < 0.001), and was 2.60 (1.71 to 3.95) in obese patients and 1.51 (1.03 to 2.22) in current smokers with more than 10 pack-years of tobacco use. In patients with PA, overweight, obesity and smoking status were not associated with an increased risk of overall postoperative complications. CONCLUSION: Perforation due to acute appendicitis was associated with current tobacco smoking. A BMI of 27.5 kg/m(2) or more and current smoking were associated with overall postoperative complications in patients with NPA.

Subarachnoid haemorrhage in Sweden 1987-2002: regional incidence and case fatality rates.

BACKGROUND: Incidence estimates of subarachnoid haemorrhage (SAH) in Sweden vary, which may be caused by regional variations. Reliable estimates of age-specific case fatality rates are lacking. We analysed regional incidence rates and case fatality rates of SAH in Sweden. METHODS: The Swedish Hospital Discharge and Cause of Death Registries from 1987 to 2002 yielded data on 18 443 patients with SAH. Incidence and case fatality rates by age, gender, region and time period were calculated by Poisson regression. RESULTS: The incidence rate was 12.4 per 100,000 person-years (95% CI 12.2 to 12.6) and increased with age, from 6.4/100,000 person-years in patients who were 30-39 years old to 25.8/100,000 person-years in patients who were older than 80 years. Incidence was higher for women (14.4 (95% CI 14.2 to 14.7)) than for men (10.3 (95% CI 10.3 to 10.6)), and higher in the north than in the south (RR 1.31 (95% CI 1.25 to 1.37)). This geographical gradient was more evident in women (RR 1.41 (95% CI 1.33 to 1.49)) than in men (RR 1.23 (95% CI 1.15 to 1.33)). The 28-day case fatality rate was 31.7% (95% CI 31.0 to 32.3). It increased with age from 18.1% (95% CI 16.0 to 20.3) in patients who were 30-39 years old to 57.6% (95% CI 55.2 to 59.9) in patients over 80 years, then levelling off. Over time (1995-2002 compared with 1987-1994), the incidence rate decreased (RR 0.93 (95% CI 0.90 to 0.96)) and case fatality rate decreased (RR 0.89 (95% CI 0.85 to 0.93)). CONCLUSIONS: SAH incidence rates in Sweden increase from south to north, more in women than in men. Octogenarians have a quadrupled incidence and a tripled case fatality compared with young adults. During 16 years, both incidence and case fatality have decreased.

The risk for cutaneous malignant melanoma, melanoma in situ and intraocular malignant melanoma in relation to tobacco use and body mass index.

BACKGROUND: The incidence of cutaneous malignant melanoma (CMM) and melanoma in situ (MIS) has been increasing during the last 50 years. Malignant melanoma (MM) is also the most common intraocular malignancy (IMM). Besides ultraviolet radiation, the cause of these tumours is largely unknown. OBJECTIVES: We designed a study to examine the effect of body mass index (BMI) and tobacco use on the risk for MM and MIS. METHODS: Analyses were performed on a nationwide cohort of 339 802 Swedish construction workers. Exposure information was collected prospectively by questionnaires combined with personal interviews. RESULTS: Follow up yielded a total of 7 663 400 person-years during which 1639 workers developed MM/MIS. The risk for MM/MIS was reduced in current or previous smokers compared with those who had never smoked, both when analysing all smoking tobacco products combined and when analysing cigarette and pipe smokers separately. The risk was further diminished with longer duration of smoking and greater quantity of tobacco smoked. The effect was more evident in CMM/MIS than in IMM. Snuff taking conferred a decreased risk for CMM/MIS, and a BMI over normal weight range conferred an increased risk for CMM. CONCLUSIONS: Tobacco smoking was found to be inversely associated with the risk for CMM and MIS. The mechanism of action is unknown but it has been suggested to be due to the immune suppressive effect that tobacco exerts which would be protective against deleterious immune reactions caused by, for example, the sun. Neither is the mechanism behind the higher risk for CMM due to being overweight known. One hypothesis is that it is an effect of a hormonal imbalance. Further studies are required to elucidate these mechanisms.

The effect of tobacco consumption and body mass index on complications and hospital stay after inguinal hernia surgery.

BACKGROUND: The extent to which lifestyle factors such as tobacco consumption and obesity affect the outcome after inguinal hernia surgery has been poorly studied. This study was undertaken to assess the effect of smoking, smokeless tobacco consumption and obesity on postoperative complications after inguinal hernia surgery. The second aim was to evaluate the effect of tobacco consumption and obesity on the length of hospital stay. METHODS: A cohort of 12,697 Swedish construction workers with prospectively collected exposure data on tobacco consumption and body mass index (BMI) from 1968 onward were linked to the Swedish inpatient register. Information on inguinal hernia procedures was collected from the inpatient register. Any postoperative complication occurring within 30 days was registered. In addition to this, the length of hospitalization was calculated. The risk of postoperative complications due to tobacco exposure and BMI was estimated using a multiple logistic regression model and the length of hospital stay was estimated in a multiple linear regression model. RESULTS: After adjusting for the other covariates in the multivariate analysis, current smokers had a 34% (OR 1.34, 95% CI 1.04, 1.72) increased risk of postoperative complications compared to never smokers. Use of "Swedish oral moist snuff" (snus) and pack-years of tobacco smoking were not found to be significantly associated with an increased risk of postoperative complications. BMI was found to be significantly associated with an increased risk of postoperative complications (P = 0.04). This effect was mediated by the underweighted group (OR 2.94; 95% CI 1.15, 7.51). In a multivariable model, increased BMI was also found to be significantly associated with an increased mean length of hospital stay (P < 0.001). There was no statistically significant association between smoking or using snus, and the mean length of hospitalization after adjusting for the other covariates in the model. CONCLUSION: Smoking increases the risk of postoperative complications even in minor surgery such as inguinal hernia procedures. Obesity increases hospitalization after inguinal hernia surgery. The Swedish version of oral moist tobacco, snus, does not seem to affect the complication rate after hernia surgery at all.

A population-based binational register for monitoring long-term outcome and possible disease concordance among blood donors and recipients.

BACKGROUND AND OBJECTIVES: Even with appropriate donor deferrals and advanced screening tests, the risk of disease transmission through blood transfusion cannot be completely disregarded. Efficient monitoring of possible disease transmission between blood donors and recipients should be an important component of a comprehensive haemovigilance system. MATERIALS AND METHODS: We assembled the Scandinavian Donations and Transfusions (SCANDAT) database, with data on virtually all blood donors and recipients who have been registered at least once in any of the computerized local blood bank databases in Sweden and Denmark since the start of computerized registration in 1966. The records of these individuals, with their entire computerized donation and/or transfusion histories and all donor-component-recipient connections, were linked to nationwide population and health registers to attain essentially complete follow-up for up to 36 years regarding reproduction, hospital morbidity, cancer, and death. RESULTS: After data cleaning, the database contained 1,134,290 blood donors who contributed 15,091,280 records of donations and 1,311,079 recipients who received 11,693,844 transfusions. The data quality in the existing data sources was satisfactory. From the data obtained from local blood banks, 4.6%, 1.6%, and 6.4% of the person, donation, and transfusion records, respectively, had to be discarded after review of the legitimacy of recorded values, and comparisons with independent, external databases. CONCLUSION: It is possible to use existing computerized data, collected in routine health care, in haemovigilance systems for monitoring long-term outcome and disease concordance in blood donors and transfusion recipients.

Fractures of the shaft of the humerus. An epidemiological study of 401 fractures.

We studied the epidemiology of 401 fractures of the shaft of the humerus in 397 patients aged 16 years or older. The incidence was 14.5 per 100,000 per year with a gradually increasing age-specific incidence from the fifth decade, reaching almost 60 per 100, 000 per year in the ninth decade. Most were closed fractures in elderly patients which had been sustained as the result of a simple fall. The age distribution in women was characterised by a peak in the eighth decade while that in men was more even. Simple fractures were by far the most common and most were located in the middle or proximal shaft. The incidence of palsy of the radial nerve was 8% and fractures in the middle and distal shaft were most likely to be responsible. Only 2% of the fractures were open and 8% were pathological. These figures are representative of a population with a low incidence of high-energy and penetrating trauma, which probably reflects the situation in most European countries.

The impact of tobacco use and body mass index on the length of stay in hospital and the risk of post-operative complications among patients undergoing total hip replacement.

We carried out a retrospective cohort study of 3309 patients undergoing primary total hip replacement to examine the impact of tobacco use and body mass index on the length of stay in hospital and the risk of short term post-operative complications. Heavy tobacco use was associated with an increased risk of systemic post-operative complications (p = 0.004). Previous and current smokers had a 43% and 56% increased risk of systemic complications, respectively, when compared with non-smokers. In heavy smokers, the risk increased by 121%. A high body mass index was significantly associated with an increased mean length of stay in hospital of between 4.7% and 7%. The risk of systemic complications was increased by 58% in the obese. Smoking and body mass index were not significantly related to the development of local complications. Greater efforts should be taken to reduce the impact of preventable life style factors, such as smoking and high body mass index, on the post-operative course of total hip replacement.

Tobacco smoking, snuff dipping and the risk of cutaneous squamous cell carcinoma: a nationwide cohort study in Sweden.

We investigated whether tobacco use causes cutaneous squamous cell carcinoma (CSCC) in a large cohort study with complete and long-term follow-up. A total of 756 incident cases occurred in a cohort of 337,311 men during a 30-year follow-up period, but no association was found between any kind of smoking tobacco use and CSCC risk, nor any risk change with increasing dose, duration or time since smoking cessation. Snuff use was associated with a decreased risk of CSCC. Overall, our study provides no evidence that tobacco use increases the risk of CSCC.

Cancer risk following organ transplantation: a nationwide cohort study in Sweden.

A substantial excess risk of lymphomas and nonmelanoma skin cancer has been demonstrated following organ transplantation. Large sample size and long follow-up time may, however, allow more accurate risk estimates and detailed understanding of long-term cancer risk. The objective of the study was to assess the risk of cancer following organ transplantation. A nationwide cohort study comprising 5931 patients who underwent transplantation of kidney, liver or other organs during 1970-1997 in Sweden was conducted. Complete follow-up was accomplished through linkage to nationwide databases. We used comparisons with the entire Swedish population to calculate standardised incidence ratios (SIRs), and Poisson regression for multivariate internal analyses of relative risks (RRs) with 95% confidence intervals (CI). Overall, we observed 692 incident first cancers vs 171 expected (SIR 4.0; 95% CI 3.7-4.4). We confirmed marked excesses of nonmelanoma skin cancer (SIR 56.2; 95% CI 49.8-63.2), lip cancer (SIR 53.3; 95% CI 38.0-72.5) and of non-Hodgkin's lymphoma (NHL) (SIR 6.0; 95% CI 4.4-8.0). Compared with patients who underwent kidney transplantation, those who received other organs were at substantially higher risk of NHL (RR 8.4; 95% CI 4.3-16). Besides, we found, significantly, about 20-fold excess risk of cancer of the vulva and vagina, 10-fold of anal cancer, and five-fold of oral cavity and kidney cancer, as well as two- to four-fold excesses of cancer in the oesophagus, stomach, large bowel, urinary bladder, lung and thyroid gland. In conclusion, organ transplantation entails a persistent, about four-fold increased overall cancer risk. The complex pattern of excess risk at many sites challenges current understanding of oncogenic infections that might become activated by immunologic alterations.

[Experimental model of infection of Helicobacter pylori in the mouse. A study of gastric damage caused by indomethacin]. / Modelo experimental de infección por Helicobacter pylori en el ratón. Estudio del daño gástrico producido por indometacina.

INTRODUCTION: The action of non-steroidal anti-inflammatory drugs (NSAIDs) on the Helicobacter Pylori (Hp) infected mucosa is a matter of debate. Some authors consider them to cause additive iatrogeny whilst others attribute a purportedly protective action to them. The development of on experimental animal model could help clarify this phenomenon. OBJECTIVES: 1--To develop an animal model of Hp gastric infection. 2--To evaluate the aggressiveness of NSAIDs in this model. MATERIALS AND METHODS: Male 6 month old BALC/C mice weighing 38 g were studied. Pylori Hp infection was ruled out. On three occasions, in the same week, 18 mice were inoculated intra-gastrically with 0.6 ml of Hp culture broth (brain-heart infusion) containing 1 x 10 8-1 x 10 9 CFU/ml. Another group of mice were inoculated with sterile saline. After two months the mice were killed and their stomachs studied. They were divided into groups: a) 6 Hp negative control mice. b) 8 Hp negative mice with prior intra-peritoneal injection of 25 mg/Kg indomethacin (24 hs.) c) 8 mice inoculated with Hp with indomethacin. d) 8 mice inoculated with Hp, without indomethacin. The stomachs were opened along the greater curvature and photographed macroscopically in order to map the necrotic area. The antrums were biopsied to test for urease and separate antrum and body specimens were send for staining with Warthin-Starry H & B and histopathology. RESULTS: All the mice inoculated with Hp acquired the infection. The necrotic area was larger in Group B: 55.5 +/- 7.87 mm than in Group C: 15 +/- 1.82 mm P < 0.00019. HISTOLOGY: Group A: normal mucosa. Group B: extensive coagulation necrosis and focal erosions. Group C: ulcers with inflammatory infiltrate and smaller necrotic area, presence of Hp on the surface epithelium. Group D: no ulcers, Hp present. CONCLUSION: An animal model of Hp infection was successfully developed Hp infection could play a potentially protective role against indomethacin aggression in the mouse.

Primary brain tumors following traumatic brain injury--a population-based cohort study in Sweden.

OBJECTIVES: The aim of this study was to explore the association between traumatic brain injury and brain tumor development. METHODS: A cohort of patients hospitalized for traumatic brain injury during 1965-1994 was compiled using the Swedish Inpatient Register. Complete follow-up through 1995 was attained through record linkage with the Swedish Cancer Register, the Cause of Death Register, and the Emigration Register. Standardized incidence ratios (SIRs), defined as the ratios of the observed to the expected numbers of brain tumors, were used as the measure of relative risk. The expected number of brain tumors was calculated by multiplying the observed person-time by age-, gender- and calendar year-specific incidence-rates derived from the general Swedish population. RESULTS: The cohort included 311,006 patients contributing 3,225,317 person-years. A total of 281 cases of brain tumors were diagnosed during follow-up. No associations were found between traumatic brain injury and the risk of primary brain tumors, neither overall (SIR: 1.0; 95% confidence interval (CI): 0.9-1.2), nor in analyses broken down by main groups of brain tumors. Stratified analyses according to age at entry into the cohort, year of follow-up, and severity of the brain injury all showed essentially the same null results. CONCLUSION: No association between traumatic head injury and primary brain tumors has been found.

Modelo experimental de infeccion por Helicobacter pylori en el raton. Estudio del dano gastrico producido por indometacina / Experimental model of infection of Helicobacter pylori in the mouse. A study of gastric damage caused by indomethacin

INTRODUCTION: The action of non-steroidal anti-inflammatory drugs (NSAIDs) on the Helicobacter Pylori (Hp) infected mucosa is a matter of debate. Some authors consider them to cause additive iatrogeny whilst others attribute a purportedly protective action to them. The development of on experimental animal model could help clarify this phenomenon. OBJECTIVES: 1--To develop an animal model of Hp gastric infection. 2--To evaluate the aggressiveness of NSAIDs in this model. MATERIALS AND METHODS: Male 6 month old BALC/C mice weighing 38 g were studied. Pylori Hp infection was ruled out. On three occasions, in the same week, 18 mice were inoculated intra-gastrically with 0.6 ml of Hp culture broth (brain-heart infusion) containing 1 x 10 8-1 x 10 9 CFU/ml. Another group of mice were inoculated with sterile saline. After two months the mice were killed and their stomachs studied. They were divided into groups: a) 6 Hp negative control mice. b) 8 Hp negative mice with prior intra-peritoneal injection of 25 mg/Kg indomethacin (24 hs.) c) 8 mice inoculated with Hp with indomethacin. d) 8 mice inoculated with Hp, without indomethacin. The stomachs were opened along the greater curvature and photographed macroscopically in order to map the necrotic area. The antrums were biopsied to test for urease and separate antrum and body specimens were send for staining with Warthin-Starry H & B and histopathology. RESULTS: All the mice inoculated with Hp acquired the infection. The necrotic area was larger in Group B: 55.5 +/- 7.87 mm than in Group C: 15 +/- 1.82 mm P < 0.00019. HISTOLOGY: Group A: normal mucosa. Group B: extensive coagulation necrosis and focal erosions. Group C: ulcers with inflammatory infiltrate and smaller necrotic area, presence of Hp on the surface epithelium. Group D: no ulcers, Hp present. CONCLUSION: An animal model of Hp infection was successfully developed Hp infection could play a potentially protective role against indomethacin aggression in the mouse.

Modelo experimental de infección por Helicobacter pylori en el ratón. Estudio del daño gástrico producido por indometacina. / [Experimental model of infection of Helicobacter pylori in the mouse. A study of gastric damage caused by indomethacin]

INTRODUCTION: The action of non-steroidal anti-inflammatory drugs (NSAIDs) on the Helicobacter Pylori (Hp) infected mucosa is a matter of debate. Some authors consider them to cause additive iatrogeny whilst others attribute a purportedly protective action to them. The development of on experimental animal model could help clarify this phenomenon. OBJECTIVES: 1--To develop an animal model of Hp gastric infection. 2--To evaluate the aggressiveness of NSAIDs in this model. MATERIALS AND METHODS: Male 6 month old BALC/C mice weighing 38 g were studied. Pylori Hp infection was ruled out. On three occasions, in the same week, 18 mice were inoculated intra-gastrically with 0.6 ml of Hp culture broth (brain-heart infusion) containing 1 x 10 8-1 x 10 9 CFU/ml. Another group of mice were inoculated with sterile saline. After two months the mice were killed and their stomachs studied. They were divided into groups: a) 6 Hp negative control mice. b) 8 Hp negative mice with prior intra-peritoneal injection of 25 mg/Kg indomethacin (24 hs.) c) 8 mice inoculated with Hp with indomethacin. d) 8 mice inoculated with Hp, without indomethacin. The stomachs were opened along the greater curvature and photographed macroscopically in order to map the necrotic area. The antrums were biopsied to test for urease and separate antrum and body specimens were send for staining with Warthin-Starry H & B and histopathology. RESULTS: All the mice inoculated with Hp acquired the infection. The necrotic area was larger in Group B: 55.5 +/- 7.87 mm than in Group C: 15 +/- 1.82 mm P < 0.00019. HISTOLOGY: Group A: normal mucosa. Group B: extensive coagulation necrosis and focal erosions. Group C: ulcers with inflammatory infiltrate and smaller necrotic area, presence of Hp on the surface epithelium. Group D: no ulcers, Hp present. CONCLUSION: An animal model of Hp infection was successfully developed Hp infection could play a potentially protective role against indomethacin aggression in the mouse.