Fibrogenesis in the pancreas after acinar cell injury.

Fibrosis within the pancreas is a key feature of chronic pancreatitis and pancreatic cancer. It has now been well demonstrated that following injury to acinar cells, pancreatic stellate cell activation, migration and proliferation is the key mediator of this process. Many cytokines and growth factors have been studied, particularly TGF-beta, which appears to be the major stimulus to fibrinogenesis. There is current interest in the mechanisms of phenotypic change between the active and quiescent forms, apoptosis and the signalling pathways that may be involved. The pancreatic stellate cell is likely to play an important role in maintaining the normal extracellular matrix; we speculate that the dysregulation of this process is an important factor in chronic pancreatitis.

Influence of cytokine and ICAM-1 gene polymorphisms on susceptibility to chronic pancreatitis.

AIMS: To test the hypothesis that single nucleotide polymorphisms (SNPs) within genes (or their promoter regions) encoding cytokines, growth factors, and intercellular adhesion molecules modulate the risk of development of chronic pancreatitis (CP). METHODS: DNA was extracted from peripheral blood leucocytes or formalin fixed, paraffin wax embedded tissue from 53 patients with CP and 266 healthy controls. SNPs within the interleukin 1beta (IL-1beta), IL-6, IL-8, tumour necrosis factor alpha (TNFalpha) and vascular endothelial growth factor (VEGF) gene promoter regions and the transforming growth factor beta1 (TGFbeta1) and intercellular cell adhesion molecule 1 (ICAM-1) genes were genotyped by the amplification refractory mutation system polymerase chain reaction or 5' nuclease (Taqman) techniques. Patient-control comparisons were made using 2 x 2 contingency tables and chi2 analyses. RESULTS: A non-significant decrease in the frequency of the IL-8 -251 AA genotype and a non-significant increase in the frequency of the ICAM-1 +469 GA genotype was seen in patients compared with controls. No associations were identified between SNPs in the promoter regions of the IL-1beta, IL-6, or TNFalpha proinflammatory cytokines genes or the TGFbeta1 and VEGF genes and susceptibility to CP. CONCLUSIONS: This preliminary study suggests that genetic polymorphism within several cytokine genes is unlikely to influence susceptibility to CP, but the possible role of IL-8 and ICAM-1 polymorphisms in the development of this disease requires further investigation.

Laboratory markers predict bone loss in Crohn's disease: relationship to blood mononuclear cell function and nutritional status.

BACKGROUND: Crohn's disease is associated with reduced bone density. The power of simple markers of systemic inflammation to identify higher rates of bone loss, in Crohn's disease, is uncertain. This relationship and the role of circulating (peripheral blood) mononuclear cells were investigated in a case-control study. METHODS: Urinary deoxypyridinoline/creatinine and serum osteocalcin concentrations were compared in male and premenopausal females with "active" Crohn's disease (C-reactive protein > or = 10 and/or erythrocyte sedimentation rate > or = 20) (n = 22) and controls with "quiescent" Crohn's disease (C-reactive protein < 10 and erythrocyte sedimentation rate < 20) (n = 21). No patients were receiving corticosteroid therapy. Production of tumour necrosis factor-alpha, interferon-gamma and prostaglandin E(2) by peripheral blood mononuclear cells were measured. RESULTS: Active Crohn's disease was associated with a higher deoxypyridinoline/creatinine (P = 0.02) and deoxypyridinoline/creatinine:osteocalcin ratio (P =0.01) compared with quiescent Crohn's disease, but similar osteocalcin (P = 0.24). These were not explained by vitamin D status, dietary intake or nutritional status. However, production of interferon-gamma by concanavalin A-stimulated peripheral blood mononuclear cells was lower in active Crohn's disease (P = 0.02) and correlated negatively with the deoxypyridinoline/creatinine:osteocalcin ratio (r = -0.40, P = 0.004). CONCLUSION: In Crohn's disease, raised C-reactive protein and erythrocyte sedimentation rate may indicate higher rates of bone loss and, if persistent, the need to assess bone mass even where disease symptoms are mild. This may be partly explained by altered production of interferon-gamma by peripheral blood mononuclear cells.

Apoptosis and proliferation of acinar and islet cells in chronic pancreatitis: evidence for differential cell loss mediating preservation of islet function.

BACKGROUND: Chronic pancreatitis is characterised clinically by early exocrine insufficiency, with diabetes mellitus occurring as a late phenomenon. This is mirrored pathologically by extensive acinar cell destruction and islet preservation. The mechanisms underlying this differential rate of cellular destruction are unknown. AIMS: To test the hypothesis that acinar loss and islet preservation in chronic pancreatitis occurs due to differential epithelial kinetics and investigate the role of inflammatory cells and cell cycle associated molecules. METHODS: Archival tissue from six chronic pancreatitis cases was compared with six normal controls using TUNEL and immunohistochemistry for CD3, CD20, CD68, MIB-1, Bcl-2, Bax, Fas, Fas ligand, retinoblastoma protein (Rb), and tissue inhibitor of metalloproteinases 1 (TIMP-1) and 2 (TIMP-2). RESULTS: The acinar cell apoptotic index (AI) and proliferation index were higher in chronic pancreatitis than controls. T lymphocytes diffusely infiltrated fibrous bands and acini but rarely islets. Acinar Bcl-2 expression exceeded islet expression in chronic pancreatitis and controls while Bax was strongly expressed by a subset of islet cells and weakly by centroacinar cells. Islet Fas and Fas ligand expression exceeded acinar expression in chronic pancreatitis and controls. Acinar Rb expression was higher in chronic pancreatitis than in controls. Islets in chronic pancreatitis and controls showed intense TIMP-1 and TIMP-2 expression. CONCLUSION: Apoptosis plays a significant role in acinar loss in chronic pancreatitis. Acinar Bcl-2 and islet Bax expression indicates complex AI control. Increased acinar Rb expression in chronic pancreatitis may differentially promote acinar loss. Fas ligand expression may be restricted to islet cell membranes through TIMP-1 expression and inhibit islet damage by promoting apoptosis of cytotoxic T lymphocytes.

Comparison of calcaneal ultrasound and DXA to assess the risk of corticosteroid-induced osteoporosis: a cross-sectional study.

Patients on long-term oral corticosteroids have an increased risk of low bone mass and fragility fractures. Fracture risk rises soon after commencement of corticosteroid therapy and it is possible that these agents adversely influence bone architecture disproportionately to their effect on bone mass. The best means of assessing bone status in patients using corticosteroids remains uncertain, but quantitative ultrasound of the calcaneus may provide evidence of microarchitectural changes not detected by dual-energy X-ray absorptiometry (DXA). Patients with Crohn's disease have an increased risk of low bone mineral density (BMD), the etiology of which is multifactorial but includes corticosteroid use. We studied 118 consecutive patients with Crohn's disease, 21 of whom used continuous oral corticosteroids, 70 of whom were intermittent users, and 27 who had never used the drug. All patients received DXA of the lumbar spine, hip and calcaneus and quantitative ultrasound (QUS) of the calcaneus. The different techniques were compared using a femoral neck T-score < or = -1.5 as the threshold of corticosteroid-induced osteoporosis. When compared with the femoral neck T-score, there were no significant differences between the predictive values of lumbar spine DXA, calcaneal DXA or calcaneal QUS to identify low femoral neck BMD. However, the absolute T-score required to give similar discriminatory capacity to femoral neck T-score varied substantially (T= -0.81 to -1.5) between the different measurement techniques and sites.

An anatomic and physiological model of hepatic vascular system.

Hepatic function can be characterized by the activity/time curves obtained by imaging the aorta, spleen, and liver. Nonparametric deconvolution of the activity/time curves is clinically useful as a diagnostic tool in determining organ transit times and flow fractions. The use of this technique is limited, however, because of numerical and noise problems in performing deconvolution. Furthermore, the interaction of part of the tracer with the spleen and gastrointestinal tract, before it enters the liver, further obscures physiological information in the deconvolved liver curve. In this paper, a mathematical relationship is derived relating the liver activity/time curve to portal and hepatic behavior. The mathematical relationship is derived by using transit time spectrum/residence time density theory. Based on this theory, it is shown that the deconvolution of liver activity/time curves gives rise to a complex combination of splenic, gastrointestinal, and liver dependencies. An anatomically and physiologically plausible parametric model of the hepatic vascular system has been developed. This model is used in conjunction with experimental data to estimate portal, splenic, and hepatic physiological blood flow parameters for eight normal volunteers. These calculated parameters, which include the portal flow fraction, the splenic blood flow fraction, and blood transit times are shown to adequately correspond to published values. In particular, the model of the hepatic vascular system identifies the portal flow fraction as 0.752 +/- 0.022, the splenic blood flow fraction as 0.180 +/- 0.023, and the liver mean transit time as 13.4 +/- 1.71 s. The model has also been applied to two portal hypertensive patients. The variation in some of the model parameters is beyond normal limits and is consistent with the observed pathology.

An anatomical and physiological model of the renal parenchyma--model development and parametric identification.

Renal function is often characterized by the activity/time curves obtained by imaging the aorta and kidney. Non-parametric deconvolution of the activity/time curves is clinically useful as a diagnostic tool in determining renal transit times. Typically non-parametric deconvolution is performed using a technique that does not require a priori information, e.g. matrix-based and Fourier-transform methods. Using data filtering and conservation of mass constraints, non-parametric deconvolution continues to exhibit noise in the deconvolved curves. This noise hampers the identification of renal transit times. Given the shortcomings of non-parametric deconvolution, a parametric model of the renal response has been developed. Our model is shown to be anatomically and physiologically plausible. In this paper, the parametric model structure is used, in conjunction with experimental data, to estimate renal physiological parameters. These parameters include the filtration fraction, renal blood transit time and urine transit times. The model parameters are then related to the minimum transit time (MinTT), mean transit time (MTT), glomerular filtration rate (GFR) and parenchymal transit time index (PTTI). As deconvolution techniques often produce negative artifacts, Fine et al developed a technique to determine an aorta background to minimize this effect. In this paper this work is extended to determine a reasonable renal background from aorta activity/time curves. Non-parametric deconvolution is used to provide initial estimates of model parameters. The model is then fitted to twelve healthy background-corrected kidneys by an iterative parameter-estimation technique. The normal values correspond to those reported in the literature. These normal values are then used to identify renal arterial stenosis in two renal hypertensive patients. The results suggest that parametric identification, based on a renal-retention-function model, may provide additional anatomical and physiological information that is not provided by conventional non-parametric methods.

Sub-lethal poisoning by self-injection with ricin.

Ricin, one of the most potent toxins known, has a lethal dose range of 1-10 mg per kilogram (Crompton and Gall, 1980) when injected. There is no effective treatment. We report a case of sub-lethal poisoning by self-injection.

Three different methods of inhibiting lipolysis in human chyme in vitro: efficiency and effect on phase distribution of lipids.

1. The efficiencies of three different methods of inhibiting fatty acid production in chyme have been evaluated. The effects of each method on the phase distribution of fatty acids after ultracentrifugation have been studied. 2. Chyme fatty acid concentrations were measured during a 4 h incubation (a) without an inhibitor, (b) after acid treatment, (c) after addition of p-bromophenylboronic acid and (d) after heating. 3. In a separate experiment, fresh chyme was incubated to allow equilibration of lipolysis. Aliquots were treated by each inactivation method and ultracentrifuged overnight to separate the phases. Total and micellar fatty acids and glycerides were measured. 4. In the first experiment, acid treatment completely inhibited fatty acid generation producing 4 h concentrations which were 93.4 +/- 5.6% (mean +/- SEM) of initial values compared with 398.0 +/- 54.0% (P less than 0.05) for uninhibited samples. p-Bromophenylboronic acid and heating gave significant but incomplete inhibition (132.9 +/- 6.6% and 166.1 +/- 15.2% of initial concentrations, respectively). 5. Ultracentrifugation disclosed five phases in all except the acid-treated samples, which had four. Micellar phase fatty acid concentrations were significantly higher in the acid-treated than in the untreated samples (2.6 +/- 0.7 versus 1.7 +/- 0.5 mmol/l, P = 0.05), as were glyceride concentrations (1.5 +/- 0.4 vs 0.6 +/- 0.3 mmol/l, P = 0.05). 6. It was concluded that acid treatment was the most efficient inhibitor of fatty acid production, but it disrupted the phases. p-Bromophenylboronic acid gave significant inhibition without causing phase disruption and was therefore the most useful inhibitor overall.

Strontium-89 therapy: measurement of absorbed dose to skeletal metastases.

We report measurements of absorbed dose to vertebral metastases in ten patients referred for 89Sr therapy for disseminated prostatic carcinoma. Patients received a tracer dose of 85Sr at the time of 89Sr treatment and metastatic strontium retention was monitored scintigraphically for 6 mo. Metastatic 85Sr activity corrected for tissue attenuation was measured using the conjugate view principle, with special care taken to eliminate errors due to the selection of the metastatic region of interest. Metastatic volume was determined from high resolution CT images, and density inferred from Hounsfield number using the QCT bone mineral calibration of Genant and Cann. The mean absorbed dose was 850 rad/mCi (23 cGy/MBq) with a range from 220-2260 rad/mCi (6 to 61 cGy/MBq). The wide range found was consistent with the variation expected to arise due to differences in strontium renal plasma clearance (range 0.1-11.81/day) and extent of skeletal metastatic disease (varying from two small metastases to a superscan on [99mTc]MDP images) among the patients studied.

Effect of cimetidine on enzyme inactivation, bile acid precipitation, and lipid solubilisation in pancreatic steatorrhoea due to cystic fibrosis.

In pancreatic steatorrhoea, both pH-dependent bile acid precipitation and enzyme inactivation may limit the efficacy of pancreatic enzyme supplements and both may be preventable by addition of cimetidine. To separate these effects we compared postprandial jejunal aspirate from eight adults with steatorrhoea due to cystic fibrosis on three randomised treatment regimens (pancreatin, cimetidine, and both together). We also compared the results with those of previous studies of patients on no treatment, and of healthy subjects. On pancreatin 60% of the test meal entered the jejunum at pH less than 5 compared with 17% in health. Lipase concentration and lipolysis increased over the values on no treatment (14.2 vs 4.4 U/l, p less than 0.01; 16% vs 11%, p less than 0.02) but bile acid precipitation was not reduced (38% vs 27%, NS), and aqueous-phase lipid concentration decreased (6.7 vs 8.6 mM/l, p less than 0.05). On cimetidine, bile acid precipitation fell (19% vs 38%, p less than 0.05); although lipase concentration and lipolysis were lower than on pancreatin (4.8 U/l vs 14.2 U/l, p less than 0.01; 9% vs 16%, p less than 0.01) lipid solubilisation increased (8.8 vs 6.7 mM/l, p less than 0.05). On the combination, there was a marked improvement (p less than 0.02) in lipid solubilisation (18.3 mM/l), reflecting the improvement both in lipase (38.4 U/l) and lipolysis (24%), and in bile acid precipitation (5.6%). We conclude that the efficacy of pancreatin is limited by pH-dependent bile acid precipitation in addition to enzyme inactivation. The action of cimetidine in improving the efficacy of pancreatin depends on prevention of both these effects.

Effect of intrajejunal acidity on lipid digestion and aqueous solubilisation of bile acids and lipids in health, using a new simple method of lipase inactivation.

We have investigated whether acid-mediated bile acid precipitation, pancreatic enzyme inactivation, and fatty acid partitioning occur in health when intraluminal pH falls below 5. In order to assess lipolysis and aqueous solubilisation of lipid, we first developed a new technique for inactivating lipase in jejunal aspirate (acid inactivation), and showed it to be more effective and simpler than the established technique (heat inactivation). We then studied 14 healthy subjects, aspirating jejunal content for three hours after a liquid meal, and pooling according to pH. Eighteen per cent of the total aspirate was collected at pH less than 5 compared with 56% at pH greater than 6 (p less than 0.01). Forty eight per cent of the bile acids were precipitated at pH less than 5 compared with 18% at pH greater than 6 (p less than 0.01), leading to a reduction in aqueous phase bile acid concentration at low pH (2.1 mmol/l at pH less than 5 vs 5.8 mmol/l at pH greater than 6, p less than 0.01). Lipase activity was reduced at low pH (133 IU/l at pH less than 5 vs 182 IU/l at pH greater than 6, p less than 0.01), leading to reduced lipolysis at low pH (14% at pH less than 5 vs 32% at pH greater than 6, p less than 0.01). Aqueous phase lipid concentration was reduced at low pH (3.5 mmol/l at pH less than 5 vs 12.5 mmol/l at pH greater than 6, p less than 0.01). This reduction was less dependent on bile acid precipitation than on lipase inactivation and fatty acid partitioning. We conclude that intraluminal acidity influences aqueous solubilisation of bile acids and lipid in health.

Radiographic abnormalities of the duodenum in cystic fibrosis.

Radiologically demonstrable abnormalities of the duodenum are common in cystic fibrosis and are most prevalent in the second part of the duodenum. Out of 14 upper gastrointestinal barium studies performed on patients with cystic fibrosis over a period of 10 years, radiographic abnormalities of the duodenum were found in 12, an incidence of 86%. The abnormalities consisted of thickened mucosal folds, nodular indentations and effacement of the normal mucosal pattern. A duodenal stricture that was radiologically similar to a carcinoma presented as pyloric obstruction in one patient and this resolved on medical treatment. We conclude that barium studies in patients with cystic fibrosis may uncover unsuspected abnormalities of the duodenum, that these form part of the syndrome and that invasive treatment is not indicated.

Pancreatic Society of Great Britain and Ireland: Annual Meeting, 1980: Role of pH-dependent bile acid precipitation in fat maldigestion due to pancreatic steatorrhoea. Preliminary communication.

In pancreatic steatorrhoea due to cystic fibrosis (CF) a major proportion of the meal enters the jejunum below the critical pH of 5, causing bile acid (BA) precipitation and limiting aqueous solubilisation of lipid. Treatment with pancreatin alone results only in a small increase in lipolysis as the lipase is largely inactivated; aqueous lipid solubilisation is not improved as BA precipitation remains a limiting factor. Treatment with cimetidine alone, by reducing BA precipitation, improves lipid solubilisation without improving lipolysis. Treatment with cimetidine and pancreatin reduces pancreatic lipase inactivation and BA precipitation leading to the greatest improvement in lipid solubilisation.