Improving tritium exposure reconstructions using accelerator mass spectrometry.

Direct measurement of tritium atoms by accelerator mass spectrometry (AMS) enables rapid low-activity tritium measurements from milligram-sized samples and permits greater ease of sample collection, faster throughput, and increased spatial and/or temporal resolution. Because existing methodologies for quantifying tritium have some significant limitations, the development of tritium AMS has allowed improvements in reconstructing tritium exposure concentrations from environmental measurements and provides an important additional tool in assessing the temporal and spatial distribution of chronic exposure. Tritium exposure reconstructions using AMS were previously demonstrated for a tree growing on known levels of tritiated water and for trees exposed to atmospheric releases of tritiated water vapor. In these analyses, tritium levels were measured from milligram-sized samples with sample preparation times of a few days. Hundreds of samples were analyzed within a few months of sample collection and resulted in the reconstruction of spatial and temporal exposure from tritium releases. Although the current quantification limit of tritium AMS is not adequate to determine natural environmental variations in tritium concentrations, it is expected to be sufficient for studies assessing possible health effects from chronic environmental tritium exposure.

Flow cytometric enumeration of micronucleated reticulocytes: high transferability among 14 laboratories.

This laboratory previously described a single-laser flow cytometric method, which effectively resolves micronucleated erythrocyte populations in rodent peripheral blood samples. Even so, the rarity and variable size of micronuclei make it difficult to configure instrument settings consistently and define analysis regions rationally to enumerate the cell populations of interest. Murine erythrocytes from animals infected with the malaria parasite Plasmodium berghei contain a high prevalence of erythrocytes with a uniform DNA content. This biological model for micronucleated erythrocytes offers a means by which the micronucleus analysis regions can be rationally defined, and a means for controlling interexperimental variation. The experiments described herein were performed to extend these studies by testing whether malaria-infected erythrocytes could also be used to enhance the transferability of the method, as well as control intra- and interlaboratory variation. For these studies, blood samples from mice infected with malaria, or treated with vehicle or the clastogen methyl methanesulfonate, were fixed and shipped to collaborating laboratories for analysis. After configuring instrumentation parameters and guiding the position of analysis regions with the malaria-infected blood samples, micronucleated reticulocyte frequencies were measured (20,000 reticulocytes per sample). To evaluate both intra- and interlaboratory variation, five replicates were analyzed per day, and these analyses were repeated on up to five separate days. The data of 14 laboratories presented herein indicate that transferability of this flow cytometric technique is high when instrumentation is guided by the biological standard Plasmodium berghei.

Lactulose-mannitol intestinal permeability test: a useful screening test for adult coeliac disease.

The aim of this study was to determine the value of the lactulose mannitol intestinal permeability test in screening the general adult population for unrecognized enteropathy and latent coeliac disease. Subjects with positive serology (identified by screening carried out by the Belfast MONICA Project) along with controls were followed-up after 3 years and classified as having transient serology, persistent serology or coeliac disease. A 5-h urine collection was performed following the ingestion of 5 g lactulose, 2 g mannitol and glucose as an osmotic filler. Urinary concentrations of lactulose and mannitol were measured by enzymatic analysis. Percentage lactulose excretion (%LE) (0.94 versus 0.31, P<0.001) and lactulose mannitol excretion ratio (LMER) (0.12 versus 0.02, P<0.001) were significantly higher in screening-detected coeliac disease subjects compared with MONICA controls. The sensitivity of the permeability test was 87% in the screening situation compared with 81% in the clinical situation. In subjects with persistent and transient serology the LMER did not differ significantly from that of controls. The lactulose-mannitol test is a useful test for screening the general adult population for coeliac disease. Subjects with persistent and transient serology did not differ from MONICA controls and are unlikely to have latent coeliac disease.

Genetic, morphometric and immunohistochemical markers of latent coeliac disease.

BACKGROUND: It is recognized that coeliac disease may exist in a latent form characterized by HLA-DR3 and increased counts of intra-epithelial lymphocytes (IELs) and gamma/delta T cells in jejunal biopsies. To determine whether subjects with persistent serological markers 4 and 13 years after a population screening survey have the HLA constitution of coeliac disease and/or minor morphometric abnormalities of the small intestine, including raised gamma/delta T-cell counts, as possible indicators of latent coeliac disease. SUBJECTS: Participants with positive serology detected by the Belfast MONICA Project surveys (1983 and 1991) were subdivided into those with persistently positive serology (persistent serology), negative serology at follow-up (transient serology) and those with enteropathy (coeliac disease). Morphometric features were compared with MONICA controls who had negative serology and HLA antigen frequencies were compared with blood donor controls. METHODS: Subjects were followed up in 1994-1996 and were re-tested for IgA antibodies to gliadin, endomysium and reticulin. HLA typing was carried out and IELs and gamma/delta T-cell counts were assessed in jejunal biopsies in subjects who gave consent. RESULTS: Persistent serology mainly concerned antigliadin (AGA) and antireticulin (ARA) antibodies but one patient had positive antiendomysial antibody (EMA) and ARA in 1983, which became negative at follow-up, at which time they were positive for AGA. No significant differences were observed between IELs or gamma/delta T-cell counts when the persistent and transient groups were compared in turn with the MONICA controls. HLA-DR2 was expressed in 11 of 16 in the persistent group compared to 47 of 150 blood donor controls (P = 0.013). HLA-DR3 occurred in 15 of 17 coeliac patients compared to 37 of 150 blood donors (P = 0.00001). CONCLUSIONS: Persistent serological markers following population screening do not appear to indicate latent coeliac disease.

Contribution of the MHC region to the familial risk of coeliac disease.

Susceptibility to coeliac disease is genetically determined by possession of specific HLA-DQ alleles, acting in concert with one or more non-HLA linked genes. The pattern of risk seen in sibs and twins in coeliac disease is most parsimonious with a multiplicative model for the interaction between the two classes of genes. Based on a sib recurrence risk for coeliac disease of 10% and a population prevalence of 0.0033, the sib relative risk is 30. To evaluate the contribution of the MHC region to the familial risk of coeliac disease, we have examined haplotype sharing probabilities across this region in 55 coeliac disease families. Based on these probabilities the sib relative risk of coeliac disease associated with the MHC region is 3.7. Combining these results with published data on allele sharing at HLA, the estimated sib relative risk associated with the MHC region is 3.3. Therefore, the MHC genes contribute no more than 40% of the sib familial risk of coeliac disease and the non-HLA linked gene (or genes) are likely to be the stronger determinant of coeliac disease susceptibility.

The effect of treating reflux oesophagitis with omeprazole on quality of life.

BACKGROUND/AIMS: Despite the commonplace nature of heartburn and reflux oesophagitis, little is known of their impact on patients' quality of life. The aim of this study was to assess quality of life in oesophagitis patients before and after medical therapy and compare the results with a sample of the general population. METHODS: Consecutive attenders with frequent heartburn and grade II-III oesophagitis on endoscopy were recruited from one of two centres and treated with omeprazole 20 mg BD for 8-14 weeks. A symptomatic questionnaire, including the Short Form-36 (SF-36) quality of life questionnaire, was completed before and at the end of treatment. Actual quality of life scores were compared with 'expected' scores derived from a sample (n = 3015) of the Northern Ireland population. RESULTS: Seventy two (83%) of the 87 patients recruited were healed after 14 weeks therapy and 77 completed the SF-36 before and after therapy. Three quality of life parameters (bodily pain, vitality and social function) were significantly lower before treatment than the 'expected' scores. Seven of the quality of life parameters measured by the SF-36 showed a significant improvement after treatment and the eighth (mental health) just failed to achieve a significant improvement (P = 0.06). Comparison of the improvements in SF-36 scores for those who were healed with scores for those who were not healed showed no significant difference. CONCLUSIONS: Patients with grade II-III oesophagitis and frequent heartburn have lower quality of life scores for some parameters than would be expected in the general population. Treatment of the oesophagitis with omeprazole 20 mg BD causes a significant improvement not just in reflux symptoms but in several physical and mental aspects of quality of life regardless of whether or not the oesophagitis is healed.

Three- to 4.5-year prospective study of prognostic indicators in gastro-oesophageal reflux disease.

BACKGROUND: Data on the long-term natural history of gastro-oesophageal reflux disease (GORD) are sparse. This prospective study was designed to determine the clinical outcome on the basis of therapeutic requirements 3 to 4.5 years after initial diagnosis of GORD and to identify specific prognostic indicators of a poor outcome. METHODS: One hundred and one GORD patients were followed up by symptomatic questionnaire 3 to 4.5 years after diagnosis and offered repeat investigation with endoscopy and oesophageal pH monitoring if symptoms persisted. RESULTS: Seventy-seven (76%) patients responded (mean follow-up period, 39 months; range, 32-54 months); of these, 28 had grade-II or -III oesophagitis at initial endoscopy, 17 had normal endoscopy but abnormal pH monitoring, and 32 had normal investigations but frequent heartburn. At follow-up 32 (42%) were taking acid suppression therapy, and a further 15 patients started acid suppression therapy after repeat investigation indicated a need to do so, giving a total of 47 (61%) patients receiving acid suppression. The following factors predicted a need for acid suppression at follow-up: oesophagitis on initial endoscopy (P = 0.009), abnormal pH monitoring (P = 0.0005), increased age (P < 0.0005), and increased body mass index (BMI) (P = 0.001). Gender, smoking status, alcohol intake, and lower oesophageal sphincter pressure had no prognostic value. Regression analysis confirmed that age (P = 0.0007), BMI (P = 0.04), and endoscopy result (P = 0.04) all independently affected outcome. CONCLUSIONS: Most GORD patients still require acid suppression therapy 3 to 4.5 years after initial diagnosis. Age, BMI, and presence of oesophagitis at initial endoscopy all independently predict those who will require long-term acid suppression therapy.

The effect of healing oesophagitis on oesophageal motor function as determined by oesophageal scintigraphy and ambulatory oesophageal motility/pH monitoring.

BACKGROUND: Oesophagitis has been shown by standard manometry to be associated with impaired oesophageal motility, but it remains unclear if this abnormality improves with healing of oesophagitis. AIM: To determine if healing of oesophagitis improves oesophageal motility using solid bolus oesophageal transit scintigraphy and combined ambulatory oesophageal motility/pH monitoring. METHODS: Patients with grade II-III oesophagitis underwent ambulatory motility/pH monitoring (using a Konigsberg catheter with four pressure transducers at 5 cm intervals) and solid bolus scintigraphy before and after treatment with omeprazole 20 mg b.d. for 8-14 weeks. RESULTS: Three (11%) of the 28 patients failed to heal. Initial scintigraphy was abnormal in 18 (67%) of 27 patients (one refused scintigraphy). Twenty-three of the 25 healed patients had repeat studies showing no significant change in the number which were abnormal (16 (64%), P = 1.0) or the overall oesophageal transit time (P = 0.65). Due to intolerance of the technique, only 11 patients had ambulatory motility/pH performed both before and after healing, giving the study 90% power to detect a 5 mmHg increase in peristaltic amplitude. No significant improvement was seen in any motility or pH parameter after healing of oesophagitis. CONCLUSION: Analysis of oesophageal motility showed no improvement in peristaltic activity after healing of oesophagitis, suggesting that the abnormal motility is either a primary disorder or an irreversible consequence of mucosal damage.

Serological markers for coeliac disease: changes with time and relationship to enteropathy.

UNLABELLED: Antigliadin antibodies (AGA) may be present in healthy adults. One previous study has reported that IgA-AGA detected by population screening may become negative after a 6-year follow-up period. OBJECTIVES: To determine the variability of coeliac disease-associated antibodies with time and to ascertain which antibodies are predictive of the presence of enteropathy. DESIGN: A clinical follow-up study of subjects with positive serological markers detected by screening at the time of the Belfast MONICA Project. METHODS: Jejunal biopsies were carried out endoscopically by means of a Crosby capsule. IgA-antigliadin was detected by a commercial ELISA; IgA-antiendomysial and antireticulin antibodies were determined by indirect immunofluorescence. RESULTS: Of 48 subjects followed up after 4 years, 28 (58%) had developed negative serology and 20 (42%) had persistently positive serology. Thirteen of 20 subjects with persistent serology had villous atrophy. Of 68 subjects followed up after 13 years, 32 (47%) had developed negative serology and 36 (53%) had persistent serology. Of 10 subjects with persistent serology who were biopsied, four had villous atrophy. None of the subjects who developed negative serology were found to have coeliac disease. CONCLUSIONS: Persistence of serological markers as a follow-up to a population screening programme may predict enteropathy in some subjects, whereas subjects who develop negative serology may be reassured. Subjects with persistent serology and normal histology require follow-up to determine if these markers are indicative of latent coeliac disease.

Coeliac disease detected by screening is not silent--simply unrecognized.

Coeliac disease (CD) is associated with a wide spectrum of clinical presentation and may be overlooked as a diagnosis. There is some evidence that untreated CD is associated with a doubling of mortality, largely due to an increase in the incidence of malignancy and small intestinal lymphoma, which is decreased by a strict gluten-free diet. We studied the clinical features of screening-detected coeliacs compared to age- and sex-matched controls as a 3-year follow-up to a population screening survey, and followed-up subjects who had had CD-associated serology 11 years previously to determine whether they have CD or an increased mortality rate compared to the general population. Samples of the general population (MONICA 1991 and 1983) were screened for CD-associated serology and followed-up after 3 and 11 years, respectively, and assessed by a clinical questionnaire, screening blood tests and jejunal biopsy. Mortality rates for 'all deaths' and 'cancer deaths' were compared in subjects with positive serology in 1983 with reference to the general population. Thirteen coeliacs were diagnosed by villous atrophy following screening, compared to two patients with clinically detected CD, giving a prevalence of 1:122. Clinical features or laboratory parameters were not indicative of CD compared to controls. Subjects with positive serology followed up after 11 years did not have an excess mortality for either cancer deaths or all causes of death. Screening-detected CD is rarely silent and may be associated with significant symptoms and morbidity. In this limited study with small numbers, there does not appear to be an increased mortality from screening-detected CD, although the follow-up may be too short to detect any difference.

Linkage analysis of candidate regions for coeliac disease genes.

A strong HLA association is seen in coeliac disease [specifically to the DQ(alpha1*0501,beta1*0201 heterodimer], but this cannot entirely account for the increased risk seen in relatives of affected cases. One or more genes at HLA-unlinked loci also predispose to coeliac disease and are probably stronger determinants of disease susceptibility than HLA. A recent study has proposed a number of candidate regions on chromosomes 6p23 (distinct from HLA), 6p12, 3q27, 5q33.3, 7q31.3, 11p11, 15q26, 19p13.3, 19q13.1, 19q13.4 and 22cen for the location of a non-HLA linked susceptibility gene. We have examined these regions in 28 coeliac disease families by linkage analysis. There was excess sharing of chromosome 6p markers, but no support for a predisposition locus telomeric to HLA. No significant evidence in favour of linkage to coeliac disease was obtained for chromosomes 3q27, 5q33.3, 7q31.3, 11p11, 19p13.3, 19q13.1, 19q13.4 or 22cen. There was, however, excess sharing close to D15S642. The maximum non-parametric linkage score was 1.99 (P = 0.03). Although the evidence for linkage of coeliac disease to chromosome 15q26 is not strong, the well established association between coeliac disease and insulin dependent diabetes mellitus, together with the mapping of an IDDM susceptibility locus (IDDM3) to chromosome 15q26, provide indirect support for this as a candidate locus conferring susceptibility to coeliac disease in some families.

Maintenance therapy with cisapride after healing of erosive oesophagitis: a double-blind placebo-controlled trial.

BACKGROUND: There are few data on the role of prokinetic agents as maintenance therapy in moderately severe reflux oesophagitis despite the high relapse rate of this condition after healing. AIMS: To determine whether cisapride is more effective than placebo as maintenance therapy after healing of moderate erosive oesophagitis in two respects: first, in preventing symptomatic relapse and preserving quality of life; and, second, in improving oesophageal motor function. PATIENTS: Forty-two patients whose grade II-III oesophagitis had been healed with omeprazole were randomized to receive either cisapride 20 mg nocte or placebo for 6 months. Oesophageal pH monitoring and manometry were performed before starting maintenance therapy and after 4 weeks, and symptomatic status and quality of life were assessed at weeks 0, 4, 13 and 26. RESULTS: After 4 weeks of maintenance therapy, lower oesophageal sphincter pressure improved in the cisapride group (16.4-21.9 mmHg, P = 0.01) but not in the placebo group (25.5-22.7 mmHg, P = 0.2). Oesophageal pH monitoring showed no significant changes in either group. Sixteen (76%) cisapride patients and 12 (57%) placebo patients withdrew within 4 weeks owing to symptomatic relapse (P = 0.2). After 26 weeks, 21 (100%) cisapride and 17 (81%) placebo patients had relapsed (log-rank analysis of survival time P = 0.07). Quality of life parameters deteriorated in both treatment groups to a similar degree. CONCLUSION: Maintenance therapy with cisapride 20 mg nocte improves the lower oesophageal sphincter pressure in patients whose oesophagitis has been healed with omeprazole. However, cisapride is no better than placebo in preventing symptomatic relapse or deterioration in quality of life.

What is a safe waiting time for coronary artery bypass surgery?

To determine the factors that influenced doctors' prioritization and decisions on safe waiting time for coronary artery bypass surgery, 50 'paper patients', based on a random sample of cases who actually had surgery, were assessed by 33 clinicians. We used linear regression models to reflect the impact of clinical and non-clinical 'cues' on safe waiting time and priority decisions. The benefits of surgery tended to be over-estimated. For example, the average perceived gain in life expectancy for patients with left main-stem disease was 6.74 years. However, models incorporating only the perceptions of benefit as independent variables (i.e. the anticipated symptom reduction, MI risk reduction and life expectancy extension), had only modest explanatory power (mean R2 was 0.55 for safe waiting time, and 0.56 for priority decisions). Models which incorporated perceptions of benefit and the cases' clinical and non-clinical characteristics had generally much higher explanatory power (mean R2, 0.83 and 0.86, respectively). Lifestyle and demographic variables had much less impact on the doctors' judgements than the major clinical cues of angina severity and left main-stem stenosis. Demographic and lifestyle cues had different impacts on safe waiting time and priority for about 25% of doctors.

Disease progression in gastro-oesophageal reflux disease as determined by repeat oesophageal pH monitoring and endoscopy 3 to 4.5 years after diagnosis.

OBJECTIVES: Reflux oesophagitis may progress to complications such as Barrett's mucosa and stricture formation. However, few studies have assessed long-term disease progression in oesophagitis patients and fewer still have considered disease progression in the significant proportion of gastro-oesophageal reflux disease (GORD) patients who do not have oesophagitis at diagnosis. The aim of this study was to reassess GORD patients 3 to 4 years after initial diagnosis and determine whether or not disease progression had occurred. METHODS: Prospective follow-up of 101 GORD patients at least 32 months after initial assessment with oesophageal pH monitoring and upper gastrointestinal endoscopy. Patients were invited to complete a symptomatic questionnaire and undergo repeat investigation with the same techniques. RESULTS: Seventy-seven (76%) patients responded (mean follow-up period 39 months, range 32-54 months) of whom 28 initially had oesophagitis (group A), 17 had normal endoscopy but abnormal pH monitoring (group B) and 32 had normal investigations but typical reflux symptoms (group C). At the time of follow-up, 57 (74%) patients either had frequent heartburn or were taking daily acid suppression therapy. Fifty-two (68%) responders had at least one repeat investigation: 44 (57%) had repeat pH monitoring; 43 (56%) had repeat endoscopy. Three (11% of the 28 responders) group A patients had developed Barrett's mucosa, 4 (24% of responders) group B patients had developed oesophagitis and 10 (31% of responders) group C patients had developed abnormal pH monitoring (4), oesophagitis (4) or both (2). CONCLUSION: Three-quarters of GORD patients still have troublesome symptoms at least 3 years after diagnosis and a significant proportion show endoscopic progression of the condition's severity.

Necropsy findings in lysinuric protein intolerance.

Lysinuric protein intolerance (LPI) is a rare autosomal recessive inborn error of metabolism, characterised by defective transport of the cationic amino acids lysine, arginine and ornithine. To date there are few reported necropsy cases. This report describes the necropsy findings in a 21 year old female patient originally diagnosed as having LPI in 1973. Liver function tests deteriorated and immediately before death jaundice, hyperammonaemia, coma, metabolic acidosis, and a severe bleeding diathesis developed. At necropsy, there was micronodular cirrhosis of the liver with extensive fatty change in hepatocytes. The lungs showed pulmonary alveolar proteinosis. Immunofluorescence and electron microscopy revealed the presence of a glomerulonephritis with predominant IgA deposition. These necropsy findings reflect the spectrum of lesions reported in LPI, providing further evidence of an association between this condition and pulmonary alveolar proteinosis, cirrhosis and glomerulonephritis.

Natural history of reflux oesophagitis: a 10 year follow up of its effect on patient symptomatology and quality of life.

BACKGROUND: Although oesophagitis is the most common diagnosis made at upper gastrointestinal endoscopy, data on the longterm outcome of affected patients are sparse. AIMS: This study assessed the level of reflux symptoms, quality of life, drug consumption, and complications in patients at least 10 years after diagnosis of oesophagitis at one centre. PATIENTS: One hundred and fifty two patients with typical reflux symptoms and a first time diagnosis by endoscopy of grade I-III oesophagitis between 1981 and 1984, were followed up using a postal questionnaire and telephone interview. RESULTS: Eighteen of 152 patients had died, 33 failed to respond, and 101 replied (mean follow up 11 years, range 121-160 months). Over 70% of patients still had heartburn at least daily (32%) or weekly (19%) or required daily acid suppression treatment (20%). Two patients (2%) had developed oesophageal strictures and one had Barrett's oesophagus. Two of eight quality of life scores (physical function and social function) measured by the Short Form-36 were significantly lower than Northern Ireland population scores. CONCLUSION: Nearly three quarters of patients previously diagnosed as having oesophagitis still had significant morbidity related to gastro-oesophageal reflux disease more than 10 years after diagnosis. Some quality of life scores were significantly lower than those of the general population.

Effect of acute stress on oesophageal motility in patients with gastro-oesophageal reflux disease.

BACKGROUND AND AIM: Sixty four per cent of people with heartburn believe that it is exacerbated by stress. An alteration in oesophageal motility is one possible mechanism for this apparent change with stress. This study aimed to assess the effect of acute stressors on oesophageal motility in patients with gastro-oesophageal reflux disease (GORD). METHODS: Sixty patients were studied. Twenty had oesophagitis, 20 had increased oesophageal acid exposure on pH monitoring but no endoscopic oesophagitis, and 20 had neither oesophagitis nor abnormal oesophageal acid exposure. Oesophageal motility was studied in these patients during psychological stress (Stroop test) and physical stress (cold pressor test). RESULTS: Blood pressure (BP) and heart rate increased in response to both stressors (mean systolic BP increased by > 10 mm Hg, diastolic BP by > 4 mm Hg and heart rate by > 3 beats per minute (p < 0.00001). The amplitude, duration, and velocity of propagation of oesophageal peristaltic contractions were not altered by the stressors. The percentage of simultaneous waves increased in patients with oesophagitis during the cold pressor test (median increase in these patients was 6% (p < 0.05)). This effect was not noted in the patients without oesophagitis. CONCLUSION: Acute stressors did not induce significant changes in oesophageal motility in patients with GORD but no oesophagitis. For these patients, dysmotility is not likely to be a cause of oesophageal symptoms which are exacerbated by stress. There was, however, a significant increase in simultaneous waves during cold pressor stress in patients with oesophagitis.