Ultrasound Examination in Diffuse Liver Disease

Seventy-three patients with pathologic liver function tests were examined using ultrasound one day prior to liver biopsy. The ultrasound findings were compared with the histologic findings. In 23 patients enlarged lymph nodes were found in the hepato-duodenal ligament and 21 of these had active immune-mediated liver disease. Of the remaining 2 patients one had ulcerative colitis (and fatty liver) and one chronic cholecystitis (and ***haemosiderosis). Of the 33 patients with biopsy-proven active ***immune-mediated liver disease 21 had pathologic lymph nodes in the hepato-duodenal ligament at ultrasound. It was not possible to identify the ligament in 8 patients and in the remaining 4 no pathologic lymph nodes could be found. Twenty-one of these patients had normal liver echoes on ultrasound, 5 exhibited increased echogenicity and 5 had heterogeneous echogenicity. In a further 2 patients both increased echogenicity and heterogeneous parenchyma were found. Ultrasound examination of the liver parenchyma alone would thus lead to 21 of the 33 patients being classified as normal and a further 5 being classified as having fatty changes of the liver. Only 7 would be regarded as having significant liver pathology. However, if demonstration at ultrasound of pathologic lymph nodes in the hepato-duodenal ligament is regarded as being consistent with significant hepatic pathology a further 15 patients could be added to these 7 patients, giving a total of 22 out of 33 patients (67%) identified as having significant liver pathology using ultrasound alone. The reliability of ultrasound in the diagnosis of immune-mediated liver disease can thus be improved considerably by actively searching for lymph nodes in the hepato-duodenal ligament.

Severe liver damage caused by therapeutic doses of acetaminophen

Two patients who ingested therapeutic doses of acetaminophen and who developed a severe hepatotoxicity are reported. Both patients had a rather high alcohol consumption, which probably made them susceptible to the toxic effects of acetaminophen.

Magnesium, potassium and zinc deficiency in subjects with type II diabetes mellitus

The concentrations of magnesium, potassium and zinc were determined in plasma, erythrocytes, muscle biopsies, and in urine collected during 24 hours, in 18 subjects with type II diabetes mellitus (DM). Magnesium was also determined in mononuclear cells. The results were compared with those in 35 (magnesium and potassium analyses) or 26 (zinc analyses) healthy controls. Subjects with type II DM had lower concentrations of magnesium (3.79 +/- 0.32 vs. 4.29 +/- 0.22 mmol/100 g FFDS), potassium (40.5 +/- 5.17 vs. 46.1 +/- 3.81 mmol/100 g FFDS) and zinc (231 +/- 29 vs. 247 +/- 23 ng/mg FFDS) in skeletal muscle. Furthermore, the urinary excretions of magnesium and zinc were higher, as compared with those in healthy controls (5.00 +/- 2.68 vs. 3.62 +/- 1.47 mmol/24 hours, and 683 +/- 285 vs. 326 +/- 205 micrograms/24 hours, respectively). The contents of magnesium, potassium and zinc plasma did not correlate with the corresponding concentrations in skeletal muscle or circulating blood cells, as investigated in healthy controls, diabetics and in all subjects together, implying that the plasma concentrations are not useful in the assessment of electrolyte status. Hence, deficiency of electrolytes frequently occurs, and should be looked for, in subjects with type II DM.

Helicobacter pylori infection is associated with a decreased risk of developing oesophageal neoplasms

BACKGROUND

The role of Helicobacter pylori infection in the development of oesophageal malignancies was investigated through a multivariate conditional logistic regression analysis in a nested case-control study.

METHODS

Blood samples and a questionnaire on smoking and alcohol habits were collected from a cohort of 32,906 city residents during a health-screening programme between 1974 and 1992. Forty-four cases of oesophageal cancer and 149 matched controls were selected. The mean interval between screening and cancer diagnosis was 11.9 years. H. pylori seropositivity was determined by an enzyme-linked immunosorbant assay measuring IgG. Occupation was included in the statistical analysis as an indicator of socio-economic status.

RESULTS

Helicobacter pylori seropositivity was present in 10 of the cases (22.7%) and 67 of the controls (45.0%). In a multivariate model, with adjustment for occupation, tobacco and alcohol consumption, the odds ratio for developing an oesophageal malignancy when infected with H. pylori was 0.29 (95% confidence interval (CI): 0.12-0.67). Current smokers had an odds ratio of 17.3 (95% CI: 3.0-99.4) and the odds ratio for ex-smokers was 5.9 (95% CI: 1.15-29.9). High alcohol consumption was no longer significantly associated with oesophageal neoplasms after tobacco smoking was included into the model, odds ratio 1.22 (95% CI: 0.46-3.2). The protective effect of H. pylori was more pronounced for oesophageal adenocarcinoma (seven cases, odds ratio 0.16, 95% CI: 0.00-1.06) than for squamous-cell carcinoma (29 cases, odds ratio 0.41, 95% CI: 0.14-1.2).

CONCLUSIONS

Helicobacter pylori infection is associated with a decreased risk of developing an oesophageal malignancy. Current smokers and ex-smokers have instead a definite increased risk of oesophageal neoplasms.

Tobacco smoking increases the risk for gastric adenocarcinoma among Helicobacter pylori-infected individuals

BACKGROUND

The importance of tobacco smoking and Helicobacter pylori infection as risk factors in the development of gastric carcinoma was investigated through multivariate conditional logistic regression analysis in a nested case-control study.

METHODS

Blood samples and a questionnaire on smoking habits were collected from a cohort of 32,906 city residents during a health screening programme from 1974 to 1992. Fifty-six cases of gastric cancer and 224 matched controls were selected. The mean interval between screening and cancer diagnosis was 5.7 years. H. pylori infection was determined by IgG-serology. Occupation categorized into blue-collar workers, white-collar workers, self-employed and unknown occupation was included in the statistical analysis as an indicator of socio-economic status.

RESULTS

The proportion of current smokers was 61% among gastric cancer cases, versus 41% among controls. H. pylori seropositivity was present in 82% of the cases and 49% of the controls. In a multivariate model current smokers had an odds ratio (OR) of 2.2 (95% confidence interval (CI): 1.2-4.2). With different levels of tobacco consumption, smoking less than 20 g tobacco each day gave the OR of 2.1 (95% CI: 0.98-4.4), and the OR when smoking more than 20 g tobacco per day was 2.5 (95% CI: 1.1-5.6). The OR of H. pylori infection was 5.0 (95% CI: 2.2-11.2). Among H. pylori-seropositive citizens, current smoking was associated with an increased risk of 2.3 (95% CI: 1.1-4.7) compared with non-smoking H. pylori-positive persons.

CONCLUSIONS

Tobacco smoking and H. pylori are both risk factors in the development of gastric cancer, and tobacco smoking is still a risk factor among H. pylori-infected individuals. The risk of gastric cancer among H. pylori-infected current smokers is 11 times that of non-infected individuals not currently smoking.

Alpha1-antitrypsin deficiency may be a risk factor for duodenal ulcer in patients with Helicobacter pylori infection

BACKGROUND

Most individuals with Helicobacter pylori infection in Western countries have no evidence of peptic ulcer disease (PUD). We therefore assessed the PiZ deficiency variant of the major plasma protease inhibitor alpha1-antitrypsin (alpha1AT) as a risk factor for PUD in H. pylori-infected individuals.

METHODS

The cohort comprised 100 patients with endoscopically or surgically proven PUD (30 patients with duodenal ulcer (DU) and 70 patients with gastric ulcer (GU)) and 162 age- and sex-matched controls with PUD-negative endoscopic findings and no history of PUD. Plasma samples were screened for alpha1AT deficiency (PiZ) with an enzyme-linked immunosorbent assay (ELISA) and phenotyped by isoelectric focusing. H. pylori infection was evaluated with an IgG ELISA technique.

RESULTS

Among the 262 patients 17 (6.5%) were positive for the PiZ alpha1AT deficiency, a frequency of the same magnitude as in the Swedish general population (4.7%). Of the PiZ carriers 76% (13 of 17) had H. pylori antibodies compared with 61% (151 of 245) of the non-PiZ carriers (NS). The prevalence of DU tended to be higher in H. pylori-positive PiZ carriers than in non-PiZ carriers (15.4%, 4 of 26 versus 0 of 4). Furthermore, among patients with DU a high PiZ allele frequency (13.3%, 4 of 30) was found compared with the general population (4.7%) (odds ratio (OR), 3.2; 95% confidence interval (CI), 1.09-8.94; P = 0.02). All DU patients carrying the PiZ allele were positive for H. pylori. In addition, four of five PiZ carriers with H. pylori infection and PUD had DU.

CONCLUSIONS

The PiZ allele may be a contributing factor in the development of DU in H. pylori-positive individuals.

Enhancement of low density lipoprotein catabolism by non-steroidal anti-inflammatory drugs in cultured HepG2 cells

Several clinical studies have shown that different types of non-steroidal anti-inflammatory drugs (NSAIDs) can reduce the cholesterol content of atherosclerotic blood vessels. The mechanism of this reduction is not established. One possibility is that NSAIDs affect low density lipoprotein (LDL) catabolism. In this study, we investigated the effect of the NSAIDs, indomethacin, flufenamic acid, ibuprofen, acetaminophen, and also acetylsalicylic acid on LDL binding, cell-association and degradation in cultured hepatoma HepG2 cells. LDL was labelled with 125I to study LDL catabolism. Furthermore, dextran sulphate, a substance that is known to release bound LDL from its receptors, was used to study LDL receptor activity. Reverse transcription-polymerase chain reaction was used to study the messenger RNA (mRNA) of LDL receptor. Our results show that flufenamic acid, indomethacin, and to a lesser extent ibuprofen, and acetaminophen increase LDL binding, cell-association, and degradation. Flufenamic acid was most potent and increased LDL catabolism by 50-70%, whereas acetylsalicylic acid had only a modest effect. Also, flufenamic acid and indomethacin were both found to increase the synthesis of mRNA of the LDL receptor with a subsequent increase of LDL receptor protein. We also investigated the effect of indomethacin on LDL binding in the presence of the 3-hydroxy-3-methylglutaryl CoA (HMG CoA) reductase inhibitor, fluvastatin. We found that both indomethacin and fluvastatin had an additive up-regulatory effect on LDL receptor activity. In addition the effect of flufenamic acid on cell-associated LDL was examined in the presence of cyclosporine, which is known to decrease LDL catabolism. The results show that flufenamic acid can restore the inhibitory effect of cyclosporine. The study thus shows that NSAIDs enhance LDL catabolism due to increased synthesis of the mRNA for LDL receptor protein. This action might contribute to the lipid-lowering effect of NSAIDs.

An individual with a healthy phenotype in spite of a pathogenic LDL receptor mutation (C240F)

Familial hypercholesterolemia (FH) is caused by a defect in the function of the low density lipoprotein (LDL) receptor and inherited in an autosomal, codominant way. In this study we present a 13-year-old girl, compound heterozygote for the LDL receptor mutations C240F and Y167X. Fibroblasts from the patient showed very low cholesterol esterification rate, LDL uptake, and degradation compared to normal fibroblasts (< 2%, 8%, and < 2%, respectively). The C240F mutant was expressed in LDL receptor deficient CHOMldlA7 cells. Analysis of cell extracts by immunoblotting demonstrated delayed processing of the mutated LDL receptor, which was accumulated as a precursor protein of normal size. A high molecular weight form of the receptor was also detectable in these cells, which probably reflects cross-linking through the unpaired cysteine residue in the binding domain. Cells expressing the C240F mutant protein were unable to mediate uptake and degradation of LDL. The two siblings of the index case also carried the C240F mutation, but surprisingly one of them (a 17-year-old brother) showed no signs of hypercholesterolemia. This observation is consistent with the view that there may be cholesterol lowering mechanisms that can be activated, perhaps by mutations in known or hitherto unknown genes.

[Enteroscopy valuable in obscure small bowel disease. Chances are good to discover curable conditions]

Indications for enteroscopic examination of the proximal small bowel are expanding, above all in cases of gastro-intestinal bleeding of obscure origin. Of 66 patients examined enteroscopy revealed new and unforeseen diagnoses in about half of them, such as angiodysplasia and erosions (15 per cent of cases each). Former as well as ongoing bleeding was treated with electro cautery, bicap. In four cases the need for blood transfusion ceased. Ulcers, neoplasia and varices were also diagnosed. 16 out of 36 pathologic lesions were located within reach of an ordinary gastroscope, in spite of the patients being selected through repeated normal upper and lower endoscopic examinations. This emphasises the need for better quality assurance in routine endoscopic examinations.

Mutations in the low-density lipoprotein receptor gene in Swedish familial hypercholesterolaemia patients: clinical expression and treatment response

BACKGROUND

Familial hypercholesterolaemia, an autosomal co-dominant disorder caused by defects in the low-density lipoprotein receptor gene, is strongly associated with premature development of cardiovascular disease.

METHODS

In this study, we have applied a gene screening method in a population of familial hypercholesterolaemia patients in order to describe the genetic background of the disease in southern Sweden. These patients were studied with the aim of relating the presence of the different mutations to the clinical expression of the disease and to the response to pharmacological treatment.

RESULTS

In 16 out of 21 patients, potentially disease-causing low-density lipoprotein receptor gene defects were found, including five not previously described alterations (C240-->F, C122-->stop, C356-->Y, 785insG, 165delG). No defects in apolipoprotein B were found. One group of patients (n = 4) carried the mutation C122-->stop and another group of patients (n = 4) a mutation causing the substitution W66-->G. Patients in the two genotype subgroups were very similar with respect to lipid levels before treatment.

CONCLUSION

A tendency towards differential susceptibility to treatment with statins was observed for the patient groups, encouraging further comparative studies of heterozygous FH patients.

Troglitazone upregulates LDL receptor activity in HepG2 cells

The aim of this in vitro study was to investigate the effect of troglitazone, a new oral antidiabetic agent, on LDL catabolism. HepG2 cells, which are cells from a well-differentiated cell line of hepatoma cells, were cultured and used to study LDL catabolism. Different concentrations of troglitazone, all within the therapeutic range for humans, were incubated in culture medium with 125I-labeled LDL to measure cell-associated and degraded 125I-LDL. Troglitazone increased cell-associated and degraded 125I-LDL by approximately 30%. We also investigated if this effect occurred through a LDL receptor-mediated pathway or a non-LDL receptor pathway. By using dextran sulfate, a substance known to release bound LDL from its receptor, we found that troglitazone upregulated LDL receptor activity by approximately 35%. In addition, we found that troglitazone increased the expression of the LDL receptor mRNA. The effect of troglitazone was comparable with that of a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, fluvastatin, with troglitazone having an upregulatory effect similar to that of fluvastatin. Insulin within human physiological concentrations also increased LDL receptor activity. We found that troglitazone and insulin had an additive effect on LDL catabolism. Also, the effect of troglitazone on LDL catabolism was studied in the presence of cyclosporine, an immunosuppressant drug that reduces LDL catabolism mainly by decreasing LDL receptor activity. The results showed that troglitazone can compensate for the reduced LDL receptor activity induced by cyclosporine, but that cyclosporine had a residual effect on the action of troglitazone. Thus troglitazone enhanced LDL binding, cell association, and degradation by increasing LDL receptor mRNA expression, with a subsequent increase in LDL receptor activity.

Bone mineral density in patients with Crohn's disease during long-term treatment with azathioprine

OBJECTIVES

To ascertain whether patients with Crohn's disease treated with azathioprine maintained bone mineral mass better than patients treated with steroids alone.

DESIGN

Retrospective study.

SETTING

University Hospital of Malmö, Sweden.

SUBJECTS

A total of 59 patients with ileocolonic, ileocaecal or colonic Crohn's disease.

METHODS

Bone mass was assessed by dual photon X-ray absorptiometry at the level of L2-L4.

RESULTS

Patients treated with a high lifetime dose of steroids (> 5 g prednisolone) had significantly (P = 0.011) lower Z-score of L2-L4 (-0.87 +/- 1.11; 11 SD) than steroid-treated patients, who had received a low dose of prednisolone (< 5 g) (0.08 +/- 1.16 SD). Azathioprine did not negatively influence the steroid effect on bone mineral density.

CONCLUSIONS

Azathioprine does not seem to affect bone mineral density by itself. However, by being steroid-saving, it seems to conserve bone mineral mass in patients with Crohn's disease.

Association between Helicobacter pylori and gastric carcinoma in the city of Malmö, Sweden. A prospective study

BACKGROUND

We have investigated the association between Helicobacter pylori and gastric carcinoma through a nested case-control study in a single city.

METHODS

From a cohort of 32,906 residents recruited from 1974 through 1992, 56 cases of gastric adenocarcinoma and 224 matched controls were selected. The mean interval between serum collection and diagnosis was 5.7 years. Frozen serum or plasma samples were analysed for IgG antibodies against H. pylori with an enzyme-linked immunosorbent assay.

RESULTS

The overall seropositivity prevalence in gastric cancer cases was 82%, compared with 49% in controls, giving an odds ratio (OR) of 5.0 (95% confidence interval (CI), 2.2-11.5). Partial gastrectomy because of peptic ulcer 5 to 36 year before diagnosis of gastric cancer could be a confounding factor. With exclusion of 10 such cases, H. pylori seropositivity among cases was 78%, as compared with 50% in matched controls (OR, 3.9; 95% CI, 1.7-9.2). Tumours of the cardia were not associated with H. pylori (OR, 0.92; 95% CI, 0.23-3.7), which is in contrast to tumours of the fundus, corpus, and antrum, which were significantly associated (OR, 11.1; 95% CI, 2.4-71.8). This difference in location was significant (P < 0.01).

CONCLUSION

There is a significant association between prior infection with H. pylori and later development of gastric carcinoma, and the association is related to noncardia gastric cancer.

Additive inhibitory effect of hydrocortisone and cyclosporine on low-density lipoprotein receptor activity in cultured HepG2 cells

Both glucocorticoids and cyclosporine are used to prevent rejection in organ transplant recipients. However, long-term treatment with these drugs is known to induce hyperlipidemia and premature development of atherosclerosis. In previous studies, we have shown that the immunosuppressive drug cyclosporine inhibits catabolism of low-density lipoproteins (LDL) mainly by reducing the expression of LDL-receptor messenger RNA (mRNA), thus explaining the increased plasma levels of LDL cholesterol observed in patients treated with cyclosporine. In the present study, our objective was to investigate the mechanism by which glucocorticoids increase plasma levels of LDL cholesterol. We studied the catabolism of LDL in the human hepatoma cell line HepG2. Our results show that hydrocortisone at physiologically relevant concentrations inhibits LDL binding, uptake, and degradation in a dose-dependent way. Moreover, hydrocortisone also reduces the expression of LDL-receptor mRNA in a dose-dependent way. Cyclosporine also has an additive inhibitory effect on hydrocortisone in the catabolism of LDL. The 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor fluvastatin reverses the inhibitory effect of both hydrocortisone and cyclosporine. We conclude that treatment with hydrocortisone and/or cyclosporine induces increased plasma levels of LDL cholesterol because of reduced hepatic LDL receptor activity. HMG-CoA reductase inhibitors reverse this undesirable effect and thus reduce the risk of the development of atherosclerosis in patients subjected to immunosuppressive treatment.

Bambuterol raises high-density lipoprotein levels in patients with hyperlipidaemia

OBJECTIVE

The objective of this study was to investigate the effects of bambuterol (a prodrug of the beta 2-agonist terbutaline) on lipid and lipoprotein levels in patients with hyperlipidaemia. Both these drugs are extensively used in the treatment of patients with bronchial asthma. Earlier studies in healthy volunteers and in patients with noninsulin dependent diabetes mellitus have shown that terbutaline and bambuterol increase HDL cholesterol levels, and therefore bambuterol might have beneficial effects on HDL levels in patients with hyperlipidaemia.

DESIGN

The present study was a randomized, double-blind, crossover study, comparing 20 mg of bambuterol with placebo, each one given for 6-8 weeks with a 3-4 week washout period in between.

SETTING

The study was performed in an out-patient lipid clinic at Malmö University Hospital.

SUBJECTS

Thirty-one patients with hyperlipidaemia (S-cholesterol > 6.5 mmol L-1 and S-triglycerides > 2.0 mmol L-1) were included.

MAIN OUTCOME MEASUREMENTS AND RESULTS

The results showed that bambuterol increased S-HDL cholesterol levels by 7% (P = 0.012). Increases were 23% for P-HDL2 and 7% for P-HDL3 fractions, but no effect was apparent on S-apolipoprotein A-1 levels.

CONCLUSION

This study suggests that the beta 2-agonist bambuterol might be used as an alternative or as a complement in the treatment of dyslipidemic patients, when an increase in HDL cholesterol is desired.

Reversal of cyclosporine-inhibited low-density lipoprotein receptor activity in HepG2 cells by 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors

Previously we have shown that cyclosporine inhibits low-density lipoprotein (LDL) catabolism in HepG2 cells. This inhibition mainly occurs through reduced LDL-receptor activity. 3-Hydroxy-3-methylglutarylcoenzyme A (HMG-CoA) reductase inhibitors up-regulate LDL receptor activity with a subsequent increase in LDL uptake and degradation. In this study, in HepG2 cells, we investigated the effects of HMG-CoA reductase inhibitors on cellular LDL catabolism in the presence of cyclosporine. Different concentrations of cyclosporine and HMG-CoA reductase inhibitors, which were within the range of therapeutic concentrations used in humans, were added to the culture medium and the cellular LDL receptor activity was then measured. The results show that HMG-CoA reductase inhibitors reverse the down-regulatory effect of cyclosporine on LDL receptor activity, thus further supporting our previous findings and also providing a rationale for the already established treatment in cyclosporine-induced hypercholesterolemia with HMG-CoA reductase inhibitors.

Cyclosporine inhibits catabolism of low-density lipoproteins in HepG2 cells by about 25%

The aim of this study was to elucidate the possible causes of elevated low-density lipoprotein (LDL)-cholesterol levels in transplanted patients treated with the immunosuppressant drug, cyclosporine. HepG2 cells, from a well-differentiated cell-line of hepatoma cells, were cultured and used as a model for in vitro hepatocytic LDL uptake. Different concentrations of cyclosporine, which were within the range of concentrations found in humans treated with cyclosporine, were added to tissue culture medium together with 125I-LDL. The results showed that cyclosporine reduced LDL uptake and degradation in HepG2 cells by about 25%. The cells were also pretreated with cyclosporine for 1 to 24 hours and then incubated with new medium containing labeled LDL for 2 hours at 4 degrees C in an LDL-binding assay. The data showed that cyclosporine reduced the subsequent LDL binding. Cyclosporine has no toxic effects on HepG2 cells, as shown by unchanged growth capacity of the cells. By means of a 50-fold excess of unlabeled LDL, a monoclonal anti-LDL receptor antibody, and dextran sulfate, we also evaluated if this inhibition of LDL binding occurred through the LDL receptor-mediated pathway, through non-LDL receptor-mediated pathways, or through both. The results show that cyclosporine reduces LDL binding and uptake by mainly inhibiting the LDL receptor-mediated pathway. We also studied the effect of the LDL-cyclosporine complex on the binding of labelled LDL. The presence of cyclosporine in the LDL particle does not influence the binding behaviour of LDL to its receptor. We also found that cyclosporine reduces the expression of the LDL receptor messenger RNA (mRNA) by about 40%. Thus, the interpretation of this study is that cyclosporine can cause an increase in LDL-cholesterol in the plasma of transplantation patients by reducing the catabolism of LDL in the liver by inhibiting mainly the LDL receptor-mediated catabolism through an effect on LDL receptor synthesis.

Risk of relapse in new cases of ulcerative colitis and indeterminate colitis

PURPOSE

Changes in morbidity pattern of ulcerative colitis have created a need to update understanding of the course of the disease.

METHOD

A follow-up study was done of relapse rates and progression of inflammation in 571 non-selected patients with ulcerative and indeterminate colitis.

RESULTS

Relapse rate ten years after diagnosis was 70 percent in definite ulcerative colitis, 22 percent in probable ulcerative colitis, and 77 percent in indeterminate colitis. During the study period, there was no change in the relapse rate. In relapsing proctitis, 52 percent developed more extensive inflammation. Fifty-four percent of patients with only one attack of colitis had persistent signs of inflammatory bowel disease.

CONCLUSIONS

Shift in morbidity pattern to a greater proportion of patients with proctitis at diagnosis and a shorter time from onset of symptoms to diagnosis had no influence on the relapse rate. Indeterminate colitis has a worse prognosis than definite ulcerative colitis. Considering the documented efficacy of sulfasalazine, the high relapse rate calls for studies of the effectiveness of such treatment in everyday practice.

Operations in unselected patients with ulcerative colitis and indeterminate colitis. A long-term follow-up study

OBJECTIVE

To assess the need for operative treatment for ulcerative colitis and indeterminate colitis.

DESIGN

Retrospective study.

SETTING

University Hospital, Sweden.

SUBJECT

All patients diagnosed from 1958 to 1982, in Malmö, Sweden-ulcerative colitis (n = 471) and indeterminate colitis (n = 100).

MAIN OUTCOME MEASURES

Incidence of colectomy.

RESULTS

The mean follow-up was 15 years. The incidence of colectomy was 7.51, 1.90 and 36.13/1000 person years for definite ulcerative colitis, probable ulcerative colitis and indeterminate colitis, respectively. The incidence of colectomy in patients with definite ulcerative colitis in the present study was low compared with other studies. In contrast to other reports, men had a threefold risk while extent of inflammation did not influence the incidence. Patients with indeterminate colitis were a high risk group with a high incidence of colectomy. The high incidence among patients with indeterminate colitis compared with that in patients with definite ulcerative colitis was also seen in subgroups such as patients with total colitis at diagnosis, in patients in remission after the first attack, and in patients with a severe attack.

CONCLUSION

As patients with indeterminate colitis seem to be at increased risk of colectomy it could be important to distinguish them from those with ulcerative colitis. Today, however, it is not possible to identify all patients with indeterminate colitis early in the course of the disease.

Hepatic lipase secretion in human hepatoblastoma cell line Hep G2 is not related to cellular cholesterol homeostasis

The human hepatoblastoma cell line Hep G2 releases the enzyme hepatic lipase during incubation with heparin. In this study, hepatic lipase activity was released by low concentrations of heparin, and the release was linear with time for up to about 10 hours. Preincubations of cells with LDL or compactin induced marked but differential changes in hepatic lipase secretion, cellular cholesterol content and low density lipoprotein receptor activity, suggesting that the secretion of hepatic lipase is regulated independently of cholesterol homeostasis.

Ultrasound examination of the small bowel: comparison with enteroclysis in patients with Crohn disease

BACKGROUND

Screening for inflammatory small bowel disease has hereto relied on barium examination, usually performed after duodenal intubation. A noninvasive technique for imaging of the small bowel in such patients would be preferable.

METHODS

A total of 59 patients were included in the study. A small bowel barium examination (SBE) was performed after duodenal intubation using a barium and air double-contrast technique. Ultrasound (US) of the right lower quadrant was performed with a 3.5- or 5-MHz transducer. The patients fasted overnight.

RESULTS

In 37 of 39 patients with a normal SBE, US was also normal. In 20 patients, SBE showed lesions compatible with Crohn disease and in 18 of these the US study showed thickening of the bowel wall. One of these patients later tested positive for Yersinia enterocolitica. There were two false-positive and two false-negative US examinations. For detection of inflammatory disease of the small bowel, US was calculated to have a sensitivity of 0.95, specificity of 0.93, accuracy of 0.93, predictive value of a positive test was 0.90, and a predictive value of a negative test was 0.95.

CONCLUSIONS

US, therefore, seems to be a reliable method in the workup of patients suspected of having inflammatory small bowel disease. Thereby, US probably can select patients for SBF.

Low prevalence of anti-neutrophil cytoplasmic antibodies in ulcerative colitis patients with long-term remission

OBJECTIVES

In spite of a strong positive association between ulcerative colitis and the presence of perinuclear anti-neutrophil cytoplasmic antibodies (p-ANCAs), the immunogenetic significance of these antibodies remains unclear. We studied patients with quiescent disease to clarify whether ANCAs are present even in the absence of inflammation.

DESIGN

The prevalence of ANCAs was estimated blindly in 137 patients with ulcerative colitis, 128 of whom had quiescent disease with a mean duration of complete clinical and biochemical remission of 14 years. For comparison, we studied sera from 110 patients with Crohn's disease, 27 of whom had a low or intermediate grade of inflammatory activity. The mean duration of complete remission in these patients was 8.5 years.

METHODS

ANCAs were detected using indirect immunofluorescence and enzyme-linked immunosorbent assays (ELISAs).

RESULTS

Only 13 (9%) of 137 patients with ulcerative colitis had ANCAs (5% had p-ANCAs). Three patients had previously undergone colectomy. In patients with Crohn's disease, ANCAs were observed in 17 of 110 patients (15%, 6% had p-ANCAs). Fifteen of these patients had colonic disease.

CONCLUSION

In patients with ulcerative colitis free from inflammation for prolonged periods of time, ANCAs occurred less frequently than has previously been reported. Patients with Crohn's disease had the expected frequency of ANCA positivity, which for colonic Crohn's disease was comparable to that found in patients with ulcerative colitis. These findings suggest that the titre of ANCAs decreases with time in inactive disease and may be undetectable with conventional assays after several years of complete remission.

Ulcerative colitis and indeterminate colitis in the city of Malmö, Sweden. A 25-year incidence study

BACKGROUND

This study was designed to assess time trends in the incidence of ulcerative colitis and indeterminate colitis in an urban population.

METHODS

Medical records of in- and out-patients with inflammatory bowel disease were reviewed by a panel to establish the diagnosis. All histopathologic specimens and almost all radiographs were re-examined.

RESULTS

During the time period 1958 to 1982 there were 354 new cases of definite ulcerative colitis, 117 of probable ulcerative colitis, and 100 of indeterminate colitis. This corresponds to an average annual incidence per 100,000 of 5.5, 1.8, and 1.6, respectively. The incidence was higher in men than in women. Peak incidence was between 20 and 29 years, but indeterminate colitis was most common in 10- to 19-year-old males. The incidence was stable from 1958 to 1972 but then increased in almost all age groups in both sexes. The increase in annual incidence of definite ulcerative colitis from 4.2 to 9.4/10(5) corresponds to an average annual increase of about 5% (p < 0.001). The increase in the incidence of definite ulcerative colitis was due to an increased proportion of patients with proctitis.

CONCLUSIONS

This study has shown an increased incidence of ulcerative colitis and indeterminate colitis, and we have found no reason to believe that this is a spurious finding.

Incidence of colorectal cancer and all cause mortality in non-selected patients with ulcerative colitis and indeterminate colitis in Malmö, Sweden

Cancer morbidity and all cause mortality were studied prospectively in all patients with definite and probable ulcerative colitis and indeterminate colitis diagnosed from 1958 to 1982, in the city of Malmö, Sweden. The follow-up to Jan. 1, 1990 was complete for all but ten patients. Nine of the 471 patients with ulcerative colitis and three of the 100 patients with indeterminate colitis developed colo-rectal cancer. The incidence of colorectal cancer in ulcerative colitis was 1.4 per 1000 person-years. The observed number of cases was 2.1 times higher than expected; (95% C.I. 1.0-4.1), based on the age- and sex-specific cancer incidence in the city during the study period. Indeterminate colitis was associated with a higher colorectal cancer risk than ulcerative colitis; 2.4 per 1000 person-years; (SMR 8.6, 95% C.I. 1.8-25.1). Both conditions were associated with a slight increased mortality rate, for ulcerative colitis 12.6 per 1000 person-years; (SMR 1.3, 95% C.I. 1.0-1.5), and for indeterminate colitis 11.7 per 1000 person-years; (SMR 2.7, 95% C.I. 1.6-4.4). Complications of colitis were the main cause of death in both groups. The cancer risk was related to extent of disease, duration of disease and female gender. Ten out of the 12 cases with cancer had or developed total colitis. However, only seven of the 134 cases with total ulcerative colitis and two of 87 cases with total indeterminate colitis developed cancer.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorption and incorporation into tissue lipids of 3H-arachidonic- and 14C-linoleic acid: effects of ethanol in jejunal tissue cultures and in vivo

The effects of ethanol in the rat on the absorption and incorporation of 3H-arachidonic (20: 4, n-6) and 14C-linoleic acid (18:2, n-6) into tissue lipids was examined in jejunal tissue cultures in vivo. The pattern of incorporation earlier seen in the small intestine in vivo, ie. a preferential incorporation of 3H-20: 4 in comparison to 14C-18: 2 into phospholipids (PL), particularly phosphatidylethanolamine (PE) and phosphatidylinositol (PI) was seen in the jejunal tissue cultures. 10 mM ethanol slightly decreased the incorporation of 3H-20: 4 into PE and PI, but did not change the partitioning of labelled fatty acids into phospholipids and triacylglycerols (TG). Ethanol (100 mM) decreased the incorporation of both 3H and 14C into both PL and TG and caused a moderate increase in the TG/PL radioactivity ratio. Rats were also infused intraduodenally with either 10% ethanol or saline and given 3H-20: 4 and 14C-18: 2 in Intralipid. Radioactivity of tissue lipids were analysed after 1, 2 and 3 h. Ethanol did not significantly influence the absorption or the retention in small intestine, liver or heart of 3H or 14C, or the time course for the 3H- and 14C lipid radioactivity in serum. The distribution of 3H and 14C between total nonpolar lipids and individual PLs was also similar in the two groups, 3H-20: 4 thus exhibiting the same preferential incorporation into PLs, compared to 14C-18: 2, in both groups. Significant amounts of 3H and 14C appeared in phosphatidylethanol (PEth) of the small intestine, heart and liver, when the tissues from the ethanol-infused animals were stored frozen before extraction. When the tissues were extracted immediately after the experiment, the proportions of 3H and 14C migrating as PEth did not exceed 0.5%. Although sufficient amounts of ethanol and the phospholipase D activity necessary for PEth formation were thus present in the tissues examined, little PEth formation thus occurred during the ethanol infusion. In the ethanol treated group about 1% of the 3H and 14C radioactivity of the small intestine was in ethyl ester. Intraduodenal infusion of 10% ethanol in vivo thus has little acute effects on the metabolism of absorbed 18: 2 and 20: 4 in the intestinal mucosal cells. Formation of some ethyl ester occurs, however.

Upregulation of low density lipoprotein receptor activity by tumor necrosis factor, a process independent of tumor necrosis factor-induced lipid synthesis and secretion

It has been shown that tumor necrosis factor (TNF) rapidly upregulates expression of the low density lipoprotein (LDL) receptors on Hep G2 cells and acutely stimulates hepatic lipid synthesis and secretion in vivo. It may thus be possible that TNF-induced expression of LDL receptors is secondary to a decrease in cellular cholesterol content caused by TNF-stimulated lipid secretion. In order to know whether TNF upregulates LDL receptors by depletion of the cellular cholesterol content, the present experiments were designed to study the temporal relationship between TNF-stimulated expression of LDL receptor activity and TNF-induced changes in lipid synthesis and secretion in an in vitro setting by using Hep G2 cells (a highly differentiated human hepatoma cell line) as a hepatocyte model. Hep G2 cells were incubated with TNF (usually 2.5 nmol/L) for certain periods, and LDL receptor activity was evaluated by measuring [125I]LDL binding at 4 degrees C; lipid synthesis and secretion were assayed by measuring [3H]glycerol incorporation into triglycerides and phospholipids as well as [14C]acetate incorporation into cholesterol. We found that a 30-h exposure of the cells to TNF was needed for the effect of TNF to be seen on lipid synthesis and secretion as measured by incorporation of [3H]glycerol into triglycerides and phospholipids, whereas TNF rapidly (in several hours) upregulated LDL receptor activity. TNF stimulated triglyceride synthesis, but did not stimulate phospholipid synthesis. On the other hand, TNF stimulated phospholipid secretion, but did not stimulate triglyceride secretion. Exposure of the cells to TNF for 16 or 24 h neither decreased cholesterol synthesis nor stimulated cholesterol secretion as measured by [14C]acetate incorporation into cholesterol.(ABSTRACT TRUNCATED AT 250 WORDS)

Lactulose--a potential drug for the treatment of inflammatory bowel disease

Lactulose is a drug mainly used as a laxative and for the treatment of porto-systemic encephalopathy. Following oral administration, intact lactulose reaches the colon, where it is split by bacteria, leading to a reduction in faecal pH and creating intestinal conditions beneficial to Lactobacillus acidophilus and inhibitory to coliform bacteria, bacteroides, Salmonella and Shigella. It was shown that lactulose therapy clears faecal salmonella and shigella species and reduces the prevalence of urinary-tract infection and respiratory tract infections. Oral administration of lactulose abolishes and prevents systemic endotoxemia of gut origin. Therefore lactulose may be used for treatment of inflammatory bowel disease as bacteria and bacterial endotoxin have an important role in the pathogenesis of this disease.

Enhancement by lipoprotein-free plasma of the inhibitory effect of endotoxin on endocytotic catabolism of low density lipoproteins in Hep G2 cells

We previously showed that the presence of microgram levels of endotoxin inhibited low-density lipoprotein (LDL) uptake and degradation in Hep G2 cells. We also showed that both the polysaccharide and lipid A parts of endotoxins are needed for the inhibitory effects of endotoxins on cellular LDL uptake. The current study was carried out by inclusion of lipoprotein-free plasma (LFP) in tissue culture medium to observe the modulatory influence of non-lipoprotein factor(s) on endotoxin-induced inhibition of endocytotic catabolism of LDL in Hep G2 cells. We found that LFP dramatically promotes the inhibitory effect of endotoxins with a complete polysaccharide, but has no influence on the effect of the Re mutant endotoxin (from S. minnesota Re595), which lacks polysaccharide. By using gel-filtration chromatography, agarose electrophoresis and agarose isoelectric focusing, we further showed that in the presence of LFP, both the endotoxins with a complete polysaccharide and the Re mutant endotoxin complex with and anionize LDL, while in the absence of LFP, these endotoxins poorly interact with LDL. Thus, endotoxin inhibits cellular endocytotic catabolism of LDL by forming LDL-endotoxin complexes, and LFP enhances endotoxin-induced inhibition of endocytotic catabolism of LDL by promoting the interaction between endotoxin and LDL. In addition, our finding that the Re mutant endotoxin also interacts with LDL to form LDL-endotoxin complexes, but has no significant effect on LDL uptake and degradation, further supports the notion that both the polysaccharide and lipid A parts of endotoxins are needed for the inhibitory effects of endotoxins on cellular LDL uptake.

Polymyxin B complexes with and cationizes low density lipoproteins. The cause of polymyxin B-induced enhancement of endocytotic catabolism of low density lipoproteins

We previously reported that polymyxin B (PMB) enhances cellular catabolism of low density lipoproteins (LDLs) through a non-LDL receptor-mediated endocytotic pathway. These data were obtained mainly by using Hep G2 cells, a well differentiated human hepatoma cell line. In the current study, we explore the mechanisms of PMB-mediated endocytotic catabolism of LDL. We found that PMB enhanced LDL catabolism also in homozygous familial hypercholesterolemia fibroblasts, thereby establishing that PMB-mediated cellular catabolism of LDL does not involve LDL receptors. By using [14C]sucrose, and ligands for the asialoglycoprotein (ASGP) receptors, possibilities were excluded that PMB enhances cellular endocytosis of LDL, by inducing a general increase of cellular pinocytic activity or by causing endocytosis of LDL via the ASGP receptors in Hep G2 cells. We further show, by using polymyxin B coupled Sepharose 4B (PMB-Sepharose 4B) beads, that PMB binds to LDL to form a complex. This binding was tight, and changes in pH and salt concentrations had no significant effect on the binding, but unlabelled LDL competed with 125I-LDL to bind to PMB-Sepharose 4B. Urea and endotoxins decreased this binding, suggesting that PMB binds to LDL at least partially through hydrophobic interactions. Agarose gel electrophoresis of PMB-LDL indicates that PMB cationizes LDL. In conclusion, PMB binds to LDL to form a PMB-LDL complex presumably through interactions between lipid groups. This endows LDL with positive charges, which enhances LDL binding to negatively charged cell membranes, and such bound LDL is rapidly internalized through absorptive endocytosis.

Tumor necrosis factor up-regulates expression of low-density lipoprotein receptors on HepG2 cells

Tumor necrosis factor mediates most biological activities of endotoxin and also, in part, mediates endotoxin-induced disturbances in lipid metabolism. In this study, the effect of tumor necrosis factor on low-density lipoprotein receptor activity was investigated in cells of HepG2, a well-differentiated human hepatoma cell line. Pretreatment of the cells with tumor necrosis factor leads to enhanced binding, uptake and degradation of 125I-labeled low-density lipoprotein. This effect of tumor necrosis factor was dose and time dependent. Tumor necrosis factor-stimulated enhancement of low-density lipoprotein binding occurred at all stages of cell growth. However, addition of an excess of unlabeled low-density lipoprotein, to down-regulate low-density lipoprotein receptors before exposure to tumor necrosis factor of the cells, completely abolished the effects of tumor necrosis factor. Competition experiments using unlabeled low-density lipoprotein and blockage experiments with a monoclonal low-density lipoprotein receptor antibody showed that tumor necrosis factor-stimulated low-density lipoprotein binding takes place through stimulation of low-density lipoprotein receptors. Comparison of the kinetics of specific low-density lipoprotein binding in the unstimulated cells and in the tumor necrosis factor-stimulated cells indicated that tumor necrosis factor caused a 30% increase in maximum velocity with no significant change in Michaelis constant, suggesting that tumor necrosis factor increases the number of low-density lipoprotein receptors on the cells rather than changing binding affinity. Preincubation of the cells with cycloheximide or actinomycin D totally abolished the up-regulatory effect of tumor necrosis factor on low-density lipoprotein receptors. Tumor necrosis factor did not stimulate proliferation of HepG2 cells, as judged by cell protein determination or by [3H]thymidine incorporation. In conclusion, this study suggests that tumor necrosis factor up-regulates expression of low-density lipoprotein receptors on HepG2 cells by stimulation of de novo synthesis of receptors, independent of cell growth.

Hyperlipidemic response to endotoxin--a part of the host-defence mechanism

Endotoxin administration into experimental animals leads to an acute hyperlipidemic response. In addition, lipoproteins can inhibit various biological activities of endotoxin both in vitro and in vivo. The endotoxin-binding and endotoxin-inactivating abilities of lipoproteins, as well as the plasma levels of lipoproteins, are thus increased following endotoxin administration. The endotoxin-induced hyperlipoproteinemia may not only represent the consequence of endotoxemia, but may also be a physiological defence mechanism whereby the body attempts to combat the toxic effects of circulating endotoxin. This minireview discusses the interaction between lipoproteins and endotoxin, and the role of this acute hyperlipidemic response to endotoxin in the context of the host-defence mechanism.

Outcome 5 years after 360 degree fundoplication for gastro-oesophageal reflux disease

Forty patients with a mean age of 45 (range 22-65) years were operated on between 1982 and 1985 for gastro-oesophageal reflux disease with a short floppy 360 degree fundoplication. The results of the operation were determined by endoscopy, oesophageal manometry, ambulatory 24-h pH recording and symptom evaluation 6 months and 5 years after operation. These results were compared with findings in healthy controls. The median pressure in the lower oesophageal high-pressure zone was 13.3 (interquartile range (i.q.r.) 11.3-21.3) mmHg after 5 years, which did not differ significantly from the value at 6 months' follow-up or from that in controls. It was, however, significantly higher than the preoperative pressure. The median intra-abdominal length of the high-pressure zone was 1.7 (i.q.r. 1.3-2.3) cm after 5 years, significantly less than at 6 months but equal to control length. Measurement of the proportion of total time at pH < 4 at 5 years (median 0.2 (i.q.r. 0.0-0.6) per cent) and 6 months after operation revealed a significant reduction in acid reflux compared with preoperative values and normal controls. There was no significant difference in acid exposure between the two postoperative investigations. Endoscopy showed that 27 patients had no oesophagitis, three had erythema and three persistent Barrett's oesophagus 5 years after operation. Normal belching was possible in 22 patients and 18 experienced increased flatulence 5 years after fundoplication. An independent gastroenterologist found that the result was excellent in 16 patients, good in 16 and fair in four; two patients had a poor overall outcome of the operation. It is concluded that a 360 degree fundoplication provides good long-term control of reflux and that slight symptoms of overcompetence are common among patients operated on without affecting the overall result.

Lipoprotein receptor mediated metabolism of [14C]arachidonic acid labeled chylomicron remnants by Hep G2 cells

During lipolysis of chylomicron triacylglycerol by lipoprotein lipase, arachidonic acid (AA) esters are hydrolyzed at a slower rate than the predominant 16-18 carbon fatty acid esters. The further metabolism of the AA that is hereby enriched in the chylomicron remnant acylglycerols has not been investigated. In the present study, we examined the low density lipoprotein (LDL) dependent and independent metabolism of [14C]AA present in chylomicron remnants in the human hepatoma cell line Hep G2. Mesenteric duct cannulated rats were fed [14C]AA and [3H]cholesterol in corn oil, and the chyle obtained was injected intravenously into hepatectomized rats to form chylomicron remnants labeled with [14C]AA in the triacylglycerol (TG) and with 3H in the cholesteryl ester portion. The remnants were then incubated with Hep G2 cells. The uptake of [14C]AA within 2-4 h was similar to that of [3H]cholesteryl ester. After uptake into the cells, [14C]AA was preferentially incorporated into phospholipids, a high proportion being found in phosphatidylcholine, phosphatidylethanolamine and phosphatidylinositol. [14C]AA and [3H]cholesteryl ester uptake were influenced to similar extents by factors unknown to regulate the LDL receptor and by an anti-LDL receptor antibody. Addition of compactin thus increased the uptake of [14C]AA by 50% in 4 h and mevalonolactone decreased the uptake by 86%. Using an anti-LDL receptor antibody, 25.0% of [3H]cholesterol/cholesteryl ester and 37.7% of [14C]AA binding to the cells at 4 degrees C were blocked. There was no lipolysis of [14C]TG or [14C]diacylglycerol by lipase secreted into the medium during incubations.(ABSTRACT TRUNCATED AT 250 WORDS)

Endotoxins inhibit endocytotic catabolism of low-density lipoproteins in Hep G2 cells

The effects of endotoxins on the uptake and degradation of low-density lipoproteins in Hep G2, a well-differentiated human hepatoma cell line, were studied. The results showed that incubation of Hep G2 cells with 125I-labeled low-density lipoprotein in the presence of endotoxins caused decreased uptake and degradation of 125I-labeled low-density lipoprotein. The inhibitory effects of endotoxins on the uptake and degradation of 125I-labeled low-density lipoprotein were dose and time dependent. With a monoclonal low-density lipoprotein receptor antibody, it was found that endotoxins interfered with both low-density lipoprotein receptor-mediated and non-low-density lipoprotein receptor-mediated uptake. If, however, the cells were pretreated with endotoxins for 1 or 24 hr and then incubated with new medium without endotoxins, no inhibitory effect on the subsequent uptake and degradation of 125I-labeled low-density lipoprotein occurred. Endotoxins had no toxic effects on Hep G2 cells as judged by [3H]thymidine incorporation and by determination of cell growth. Also, endotoxins did not under our experimental conditions induce oxidative modification of low-density lipoprotein. Furthermore, reisolated low-density lipoprotein that had previously been incubated with endotoxin was catabolized to a lower extent by Hep G2 cells than was control low-density lipoprotein. We speculate that the inhibitory effect of endotoxins on cellular low-density lipoprotein catabolism is due to the formation of endotoxin-low-density lipoprotein complexes, which interfere with the binding of low-density lipoprotein to the cell surface.

Both the polysaccharide and lipid A parts of endotoxins are needed for the inhibitory effects of endotoxins on cellular LDL uptake

We previously reported that endotoxins inhibit low-density lipoprotein (LDL) uptake and degradation in Hep G2 cells. In the present study, we tried to elucidate which part(s) of the endotoxin molecules contribute(s) to the inhibitory effect of endotoxins on LDL uptake and degradation. The results show that the endotoxin isolated from Salmonella minnesota Re595 (Re mutant), which lacks polysaccharide, had no effect on the uptake and degradation of 125I-labelled LDL in Hep G2 cells. This mutant form also decreased the inhibitory effects of endotoxins which have complete polysaccharides on cellular LDL uptake and degradation. However, the polysaccharide part of endotoxins by itself had no effect on LDL catabolism by the cells. This suggests that both the polysaccharide and the lipid A parts of endotoxins are needed for the inhibitory effects of endotoxins on LDL uptake and degradation.

Polymyxin B enhances low density lipoprotein catabolism in hepatic and extrahepatic cells

We investigated the effects of polymyxin B (PMB), an antibiotic that binds to endotoxins, on the uptake and degradation of low density lipoproteins (LDLs) in HepG2 cells, a highly differentiated human hepatoma cell line. The results showed that PMB very effectively enhanced the binding, internalization, and degradation of LDL in HepG2 cells. The PMB-mediated enhancement of LDL uptake was not dependent on the LDL receptor-mediated pathway, as blockage of the LDL receptor by use of a monoclonal anti-LDL receptor antibody had no effect on the PMB-mediated cellular processing of LDL and PMB-mediated enhancement of LDL uptake did not cause an increase in cholesterol esterification. In addition, chloroquine and colchicine, which inhibit lysosomal degradation and cellular endocytosis, respectively, diminished PMB-enhanced degradation of LDL, indicating that PMB mediates uptake through a pathway similar to the LDL receptor-mediated pathway. The PMB-mediated uptake of LDL was sensitive to treatment with phospholipase C and pronase and was dependent on the presence of Ca2+. PMB caused similar changes in human skin fibroblasts, bovine smooth muscle cells, and bovine endothelial cells, which suggests that PMB-enhanced LDL uptake is a general cellular phenomenon. Our results thus indicate that PMB increases cellular catabolism of LDL through an endocytotic pathway not involving the LDL receptors.

Regulation of chylomicron remnant uptake in the human hepatoma cell-line Hep G2. Role of the low-density lipoprotein receptor

Uptake and degradation of chylomicron remnants by the human hepatoma cell line Hep G2 was studied. Mesenteric lymph was collected from rats and injected into hepatectomized rats to obtain chylomicron remnants. This remnant preparation was taken up and catabolized by Hep G2 cells. The uptake process was dependent on cell growth and was regulated by compactin (a HMG-CoA reductase inhibitor) which suppresses cholesterol synthesis and by mevalonolactone, which enhances cholesterol synthesis. A monoclonal anti LDL receptor antibody blocked binding of chylomicron remnants to Hep G2 cells to a degree, which was comparable to but generally lower than the suppression of low-density lipoprotein binding. The results thus indicate that in Hep G2 cells, chylomicron remnant uptake is regulated, similarly to low-density lipoprotein uptake and that a significant part of the remnant uptake is mediated through the LDL receptor.

Arachidonic acid absorption in human jejunum in organ culture: effects of ethanol

Human jejunal tissue obtained by peroral biopsy was cultured in control medium and in medium containing 100 mmol l-1 ethanol. Subsequently, the incorporation and metabolism of [3H]-arachidonic and [14C]-linoleic acid were evaluated. Of the two fatty acids a significantly higher amount of [3H]-arachidonic acid was incorporated into phospholipids and more [14C]-linoleic acid was incorporated into triacylglycerols. This preferential distribution of the labelled fatty acids was not affected by ethanol, but when ethanol was present in the tissue culture medium, there was a significant decrease in the incorporation of both fatty acids into tissue phospholipids. The study thus shows that ethanol in moderate concentrations can affect human jejunal absorption and metabolism of polyenoic fatty acids, contributing to a decrease in the amount of eicosanoid precursors available in jejunal tissue.

Cell-density-dependent release of hepatic lipase from cultured rat hepatocytes

Cultured rat hepatocytes release the enzyme hepatic lipase. In this study we investigated the effect of cell density on this metabolic function under a variety of experimental conditions. The release of hepatic lipase from cultured rat hepatocytes exhibits a cell-density dependence, the secretion per mg cell protein being increased with increasing cell density. When cell density dependence was taken into consideration no significant effect of insulin on the release of hepatic lipase from cultured hepatocytes was observed, whereas glucagon suppressed the release. Glucose stimulating the release of the enzyme, especially in cultures with high cell density.

Liver biopsy complications monitored by ultrasound

Ultrasound (US) was performed in 96 patients (on 108 occasions) 2-4 h after diagnostic liver puncture with a modified Menghini needle. Serious complications (major haemorrhages: one intraparenchymal and one into the abdominal cavity) were seen in two patients, while seven presented with minor bleedings though without any registered clinical abnormality (slight pain in one). On 11 occasions (10 patients) slight to moderate pain was observed though in combination with a normal US. Findings on US and clinical observations showed poor correlation and the number of bleeding complications discovered by US examination seems to depend upon when the study is performed. US does not replace the clinical follow-up but may be helpful in the presence of adverse clinical reactions in order to establish the type of lesion: profuse parenchymal haemorrhage versus bleeding into the abdominal cavity. This information may be helpful in the choice between conservative and surgical therapy.

Lipoprotein-deficient serum stimulates the uptake of chylomicron remnants in cultured rat hepatocytes

Rat hepatocyte monolayers were cultured in the presence of 1-10% lipoprotein-deficient foetal calf serum. This increased the uptake and degradation of chylomicron remnant cholesteryl ester significantly. The increase occurred at all cell densities, i.e. also with less dense cultures where the basal rate of uptake per mg protein was highest. This indicates that tissue culture medium content of lipoprotein cholesterol can regulate the uptake of chylomicron remnants in hepatocytes, analogous to the regulation of the LDL receptor in extrahepatic cell.

Defective synthesis of apolipoprotein A-I in jejunal mucosa in coeliac disease

Apolipoprotein A-I was studied in biopsy specimens from the duodenojejunal junction by means of an indirect immunoperoxidase technique. In normal control subjects apolipoprotein A-I was immunohistochemically detected only in the absorptive cells at the tips of villi and was mainly localized supranuclearly. In 14 patients with coeliac disease apolipoprotein A-I was virtually undetectable. This implies that the inflammatory lesion in coeliac disease decreases the intestinal mass of apolipoprotein A-I, because it destroys the villous absorptive cells. Apolipoprotein A-I concentrations in plasma were also decreased (by 40%) in patients with coeliac disease, suggesting that the intestine has a role in maintaining plasma apolipoprotein A-I levels.

Bile salts in the esophagus of patients with esophagitis

It is controversial whether bile salts are important in the pathogenesis of esophagitis. By sampling esophageal contents during ambulatory 24-h pH-monitoring we found that in a group of 18 patients with esophagitis all but 1 had detectable concentrations of bile salts in their esophagus. The concentrations of bile salts were low, however, and similar to those found in the gastric juice of 10 normal controls. It is concluded that bile salts are present in the esophagus of patients with esophagitis and that their presence results from duodenogastric reflux. The role of these refluxed bile salts in the pathogenesis of esophagitis is, however, unclear.