A role for HNF-3 in the regulation of the HNF-1 gene of the Atlantic salmon

Hepatocyte nuclear factors -1 (HNF-1) and -3 (HNF-3) are hepatocyte-enriched transcription factors that are central to the establishment and maintenance of the liver phenotype in vertebrates. In the present study we demonstrate that, in the Atlantic salmon, asHNF-3 regulates the expression of the gene for asHNF-1. Multiple putative binding sites for asHNF-3 were identified within the 5' flanking region of the HNF-1 gene using a computer-based algorithm, and these were confirmed to be functional by electrophoretic mobility shift assays. In transient transfection assays it was shown that co-expression of asHNF-3 leads to a decrease in the promoter activity of the 5' flanking region of the asHNF-1 gene.

Synergistic activation of the Atlantic salmon hepatocyte nuclear factor (HNF) 1 promoter by the orphan nuclear receptors HNF4 and chicken ovalbumin upstream promoter transcription factor I (COUP-TFI)

Hepatocyte nuclear factor 1 (HNF1) is a liver-enriched transcription factor that plays an important role in transcriptional networks involved in liver function. The promoters of mammalian HNF1 genes contains a single binding site for another liver-enriched transcription factor, the nuclear hormone receptor HNF4. A transcriptional hierarchy involving HNF4-mediated activation of the HNF1 promoter has been proposed to be of crucial importance in maintaining the differentiated hepatocyte phenotype. Here we present evidence that the Atlantic salmon HNF1 promoter contains three nuclear-hormone-receptor-binding sequences. Gel-shift assays showed that these motifs are recognized with different affinities by HNF4 and the orphan nuclear receptors chicken ovalbumin upstream promoter transcription factors COUP-TFI and COUP-TFII. In hepatoma cells, the site showing highest affinity for HNF4 appears to be crucial for promoter activity. Transfection experiments in non-hepatic cells indicated that the salmon HNF1 promoter was activated by both HNF4 and COUP-TFs. We also identified a promoter fragment encompassing the two more distal nuclear-hormone-binding sites that was activated by HNF4, unaffected by COUP-TF and showed a strong synergistic activation by HNF4/COUP-TF. Results are presented detailing these interactions in relation to the salmon HNF1 promoter architecture.

A prospective, randomized comparison of the ease and safety of variceal ligation using a multiband vs. a conventional ligation device

BACKGROUND AND STUDY AIMS

Recent advances in endoscopic technology have led to the development of multiple-banding devices which avoid the use of an overtube in endoscopic variceal ligation. In the present study we prospectively examined the safety and efficacy of one such device compared with the conventional single-band ligator.

PATIENTS AND METHODS

A total of 45 patients undergoing band ligation were randomly assigned to receive ligation using conventional techniques (n = 22), or multiband ligation (n = 23).

RESULTS

The use of the multiband device was associated with a significant reduction in sedation requirements (midazolam 7.1 mg vs. 9.9 mg, P < 0.01, multiband vs. conventional, respectively), less discomfort (4% vs. 23% severe discomfort, P < 0.05). The total time of the endoscopic session was reduced in the multiband group (8 minutes 25 seconds vs. 12 minutes 21 seconds, P < 0.01), as was the time required for application of all the bands (2 minutes 22 seconds vs. 5 minutes 34 seconds, P < 0.001), and average time taken per individual band application (36 seconds vs. 1 minute 36 secs, P < 0.01). In three patients who underwent ligation using the conventional method, the procedure was stopped because of trauma secondary to overtube application.

CONCLUSIONS

Multiband ligation is safer, quicker, and associated with less patient discomfort and morbidity when compared with conventional ligation.

Atlantic salmon HNF-3/forkhead: cDNA sequence, evolution, expression, and functional analysis

We report the isolation and characterization of a cDNA encoding an HNF-3 family member (as HNF-3) from Atlantic salmon (Salmo salar L). The important functional domains of HNF-3 proteins that have been characterized previously are revealed by segments of high identity along the alignment of the asHNF-3 with winged helix/forkhead amino acid sequences isolated from other species. A comparison of asHNF-3 cDNA and genomic DNA indicated that there were no introns present in the asHNF-3 gene. Expression of asHNF-3 protein in adult salmon tissues was not exclusive to liver but was also present in the pancreas and intestine. An RT-PCR analysis performed on salmon development showed that asHNF3 expression is detectable before gastrulation at the mid blastula transition stage. Functional analysis of the asHNF-3 protein using a characterized HNF-3 consensus binding site demonstrated that the protein can recognize and bind to specific HNF-3 consensus sequences. We also report the identification of a novel HNF3 binding site in the promoter of the Atlantic salmon transferrin gene.

Thrombin is effective in arresting bleeding from gastric variceal hemorrhage

Gastric variceal hemorrhage is associated with a high morbidity and mortality. We report the efficacy and safety of bovine thrombin in the treatment of bleeding gastric varices. At endoscopy 52 patients with hematemesis were diagnosed with bleeding gastric varices. Patients were treated by intravariceal injection with bovine thrombin and underwent further endoscopy at 72 hr and then at two-week intervals. Initial hemostasis was achieved in 49/52 patients (94%). Bleeding-related mortality at 72 hr after the index bleed was 3/52 (6%). The mean amount of thrombin used to achieve initial hemostasis was 1070 IU (range 400-2000 IU) and no adverse drug effects were observed. The median number of treatment sessions required to achieve gastric variceal ablation was 2 (range 1-3). At six weeks, 9 of 49 surviving patients (18%) rebled and one further patient died. The six-week mortality in patients treated with thrombin was 4/52 (8%). In conclusion, safe and effective hemostasis of bleeding gastric varices can be achieved by intravariceal injection with thrombin.

Thrombin is effective in arresting bleeding from gastric variceal hemorrhage

Gastric variceal hemorrhage is associated with a high morbidity and mortality. We report the efficacy and safety of bovine thrombin in the treatment of bleeding gastric varices. At endoscopy 52 patients with hematemesis were diagnosed with bleeding gastric varices. Patients were treated by intravariceal injection with bovine thrombin and underwent further endoscopy at 72 hr and then at two-week intervals. Initial hemostasis was achieved in 49/52 patients (94%). Bleeding-related mortality at 72 hr after the index bleed was 3/52 (6%). The mean amount of thrombin used to achieve initial hemostasis was 1070 IU (range 400-2000 IU) and no adverse drug effects were observed. The median number of treatment sessions required to achieve gastric variceal ablation was 2 (range 1-3). At six weeks, 9 of 49 surviving patients (18%) rebled and one further patient died. The six-week mortality in patients treated with thrombin was 4/52 (8%). In conclusion, safe and effective hemostasis of bleeding gastric varices can be achieved by intravariceal injection with thrombin.

The clinical diversity and role of chemotherapy in lymphoproliferative disorder in liver transplant recipients

BACKGROUND/AIMS

Post-transplant lymphoproliferative disorder is a well-documented complication with an incidence ranging from 2 to 10%, depending on the organ transplanted. Yet despite our increased understanding of the pathophysiology of this disease and the various treatments available, the mortality remains high at 60-80%. We present the clinical and histological features of ten adult liver transplant recipients with post-transplant lymphoproliferative disorder presenting over a 15-year period and review the therapeutic options.

METHODS

CD20/CD45RO immunostaining was used for T/B-cell markers; polymerase chain reaction and in-situ hybridisation for Epstein-Barr virus genome detection; kappa/lambda immunostaining and gene rearrangement analysis for clonality.

RESULTS

There were six females and four males (age range 24-56) with onset of post-transplant lymphoproliferative disorder-symptoms ranging from 3 to 72 months post transplant. Sites of post-transplant lymphoproliferative disorder included liver (n=4), lymph nodes (n=5), bone marrow (n=2), lungs (n=2), kidneys (n=2), brain, ovaries,: and pancreas (n=1). All lesions were classified as high-grade lymphoma, of B-cell lineage (9 tested); Epstein-Barr virus genome was detected in 7/10 cases. Three tumours were monoclonal; four were polyclonal and three undetermined. Treatment included immunosuppression reduction, antiviral therapy with acyclovir and/or chemotherapy (CHOP or VAPEC-B). Survival times for those patients not treated with chemotherapy were from 9 days to 30 months, whereas those receiving chemotherapy had remission times of 4 to 48 months.

CONCLUSIONS

Longer-term remissions can be achieved in patients treated with systemic chemotherapy, although not without morbidity. Clonality assessment is important but treatment decisions should be based primarily on clinical features of progression, as polyclonal tumours can behave as aggressively as monoclonal tumours.

Hepatocyte nuclear factor 4 (HNF4) binding sites in the salmon HNF1 promoter

We report the isolation and sequencing of a 1100-bp DNA fragment containing the salmon Hepatocyte Nuclear Factor 1 gene (sHNF1) promoter. The sHNF1 promoter cloned upstream of the chloramphenicol acetyl transferase (CAT) encoding gene is shown to be active in two cell lines of hepatic origin. DNasel footprint analysis of the proximal 400 bp reveals several protein-binding sites, including a CCAAT box, a potential site for Sp1, and three potential HNF4 binding sites. The sequence does not contain any canonical TATA box or initiator and sHNF1 transcription is initiated at four different sites spanning a region of 56 bp. Sequence comparison with the Xenopus laevis HNF1 promoter sequence did not show any significant similarity except in the region overlapping two of the potential HNF4 binding sites.

Schistosoma mansoni: interaction of nuclear extracts with the CCAAT-binding site revealed by the gel shift assay

Analysis of the 5'-flanking region of the gene encoding the 28-kDa glutathione S-transferase of Schistosoma mansoni (Sm28GST) indicated the presence of motifs identical to AP-1 and CCAAT-family transcription factor recognition sequences. Gel retardation experiments showed that nuclear extracts from adult S. mansoni bound to an oligodeoxynucleotide containing at CCAAT box. A DNA fragment corresponding to the region of Sm28GST containing the CCAAT motif was demonstrated to interact with schistosome nuclear proteins. This binding was dependent on the presence of the CCAAT pentanucleotide motif. Nuclear factor Y (NF-Y) is a member of the CCAAT transcription factor family that has absolute requirement for the CCAAT sequence and that is highly conserved throughout evolution. The results of a PCR-based strategy aimed at cloning the NF-YA protein of S. mansoni are presented.

Tissue expression of the Schistosoma mansoni 28 kDa glutathione S-transferase

The expression of the Schistosoma mansoni 28 kDa glutathione S-transferase (Sm28) was studied using molecular (PCR, in situ hybridization), and immunocytochemical techniques. The presence of Sm28 was demonstrated in all developmental stages of the parasite except the intra-uterine immature egg. In the parenchyma of male and female adult worms the distribution of Sm28 was limited to a subpopulation of parenchymal cells and to the dorsal tubercles of the male. The tegument, the muscles, the digestive tract, the neural mass, the vitelline glands, and mature gametes were not immunoreactive. Immature germinal cells in both sexes, and the ootype in the female genital system, were found to express Sm28. Deposits of immunoreactive material on host skin following cercarial penetration, exfoliation from the male tubercles, and especially emission of Sm28 from eggs in hepatic granulomas are suspected to be a source of antigen during the parasite infection. The reduction in worm fecundity previously observed in immunization experiments may result from an antibody response directed against Sm28 present in the ootype. There was no cross-reactivity observed, under the experimental conditions used, between the anti-Sm28 sera and either vertebrate or invertebrate host tissue.

[Spirapril and nitrendipine in arterial hypertension. A comparison of therapeutic effects and tolerance]

In a double-blind, randomized parallel-group investigation, a new angiotensin-converting enzyme-inhibitor, spirapril, was compared with a calcium antagonist, nitrendipine, in 266 patients with mild to moderate hypertension (diastolic blood pressure 96-119 mmHg). The object was to reduce the diastolic blood pressure measured 24 hours after intake of medicine to less than or equal to 90 mmHg. After monotherapy for four weeks with either 20 mg nitrendipine once daily or 12 mg spirapril once daily, the dosages were doubled in the patients in whom the desired blood pressure had not been obtained. After treatment for eight weeks, 12.5 mg hydrochlorthiazide daily was employed as a supplement in patients who had not yet obtained satisfactory blood pressures. Both methods of treatment resulted a lower number of patients who responded and lesser decreases in blood pressure than anticipated. No differences were found in the decreases in blood pressure resulting from the two therapeutic methods. The effect of supplementary hydrochlorthiazide to spirapril treatment was as anticipated while the combination with nitrendipine only resulted in a marginally extra decrease in blood pressure. Nitrendipine resulted in significantly more side effects and more patients defected from the investigation on account of side effects in the nitrendipine group (27%) than in the spirapril group (7%). This investigation had documented the abilities of nitrendipine and spirapril to reduce blood pressure and the side effects associated with this but does not predict whether the preparations can be employed to prevent the complications of hypertension which constitute the indications for treatment. Supplementing nitrendipine therapy with hydrochlorthiazide is not recommended.

Treatment of renovascular hypertension by unilateral nephrectomy. A follow-up study in patients above 60 years of age

The long term results of surgical intervention in 26 elderly patients with renovascular hypertension are presented. All patients were above 60 years of age at the day of operation. The majority of the patients had atherosclerotic renovascular disease with only one case of fibromuscular dysplasia. Several patients had severe extrarenal atherosclerotic disease. The diagnosis of renovascular hypertension was based upon the results of isotope renography, renal arteriography and renal vein catheterization. All patients underwent unilateral nephrectomy. Notably, no deaths or complications occurred in relation to surgery. At the follow-up study, blood pressure was lowered and the requirement for antihypertensive drugs reduced in 86% of the patients. We conclude that unilateral nephrectomy in elderly high risk patients with renovascular hypertension is a safe and efficient procedure.

Immediate central hemodynamic effects of five different beta-adrenoceptor-blocking agents, acebutolol, atenolol, pindolol, practolol, and propranolol, in patients with ischemic heart disease

The hemodynamic effects of acebutolol were studied in six patients with ischemic heart disease. The changes in heart rate, cardiac output, and arterial blood pressure were determined after intravenous administration of six increasing doses of acebutolol to a cumulative dose of 0.64 mg/kg. After the sixth dose of acebutolol, cardiac output and heart rate were reduced 15% and 8%, respectively. Pulmonary artery pressure was increased by 4 mm Hg. Arterial blood pressure was not changed significantly. The effects of graded doses of acebutolol on heart rate and cardiac output were compared with earlier obtained results after atenolol (0.19 mg/kg), pindolol (0.025 mg/kg), practolol (0.64 mg/kg), and propranolol (0.19 mg/kg). The effects of increasing doses of acebutolol and practolol were very similar and significantly different from the effects of the other three drugs in spite having been administered at equipotent doses. The hemodynamic effects of acebutolol support the hypothesis that the hemodynamic response to beta-adrenoceptor antagonist drugs at rest is determined primarily by the degree of intrinsic sympathomimetic activity, whereas beta-1 selectivity does not modify the central hemodynamic response.

Acute hemodynamic effects of pinacidil and hydralazine in essential hypertension

In a double-blind, randomized, crossover study, the effects of intravenous pinacidil, 0.2 mg/kg, were compared with those of hydralazine, 0.3 mg/kg, before and after beta-adrenoceptor blockade in six subjects with hypertension. Both drugs equally reduced total peripheral resistance by about 40%. Pinacidil reduced mean blood pressure by an average of 30 mm Hg, while the reduction after hydralazine was 10 mm Hg. The difference in antihypertensive effect resulted from greater increases in heart rate, cardiac contractility (systolic time intervals), and cardiac index (thermodilution) after hydralazine. These effects after hydralazine could not be fully abolished by beta-blockade, as could the effects after pinacidil. Pinacidil decreased pulmonary blood pressure, whereas there was a slight rise in pulmonary blood pressure after hydralazine. Forearm blood flow (venous occlusion strain gauge plethysmography) increased equally after both drugs; thus pinacidil decreased forearm vascular resistance more than hydralazine did. Serum concentrations of both drugs were within the therapeutic range and correlated with the fall in mean blood pressure. Five subjects complained of side effects after hydralazine, but none were reported after pinacidil. Hydralazine increased myocardial oxygen consumption (as estimated from the rate-pressure product) by 35%; there was no change after pinacidil. It is suggested that hydralazine has direct cardiostimulatory effects that limit its antihypertensive effectiveness. These effects increase myocardial oxygen consumption and may be responsible for the common and sometimes severe cardiovascular side effects of hydralazine.

Antihypertensive effect of diazoxide given intravenously in small repeated doses

Seven patients with acutely elevated diastolic blood pressure (DBP greater than or equal to 135 mmHg) were treated with repeated injections of diazoxide 1 mg/kg body weight i.v. at 10-min intervals. If the DBP was not reduced to 110 mmHg or less after 5 injections, a dose of 5 mg/kg was given. Serum diazoxide (total and unbound) was determined by high pressure liquid chromatography. In all the patients it was possible to reduce the blood pressure to a satisfactory level (i.e. DBP less than 110 mmHg). The individual plasma diazoxide concentrations necessary to achieve the desired response ranged from 20 to 85 micrograms/ml. A significant correlation was found between the initial venous concentration and the initial reduction in blood pressure (p less than 0.02). A high initial concentration in venous blood was associated with high protein binding ("transport function", p less than 0.05), and so were the elimination half-lives, which ranged from 14.7 to 61.3 h ("depot function", p less than 0.05). It is concluded that the previously recommended therapy of injection of 5 mg/kg as a bolus should be given only to patients who do not respond to small repeated doses.

A comparison of the acute haemodynamic effects of propranolol and pindolol at rest and during supine exercise in man

1. Dose-response curves for heart rate, cardiac output, arterial blood pressure and pulmonary artery pressure were obtained in 16 male patients after intravenous administration of three increasing doses of pindolol, propranolol or placebo. All patients had an uncomplicated acute myocardial infarction 6-8 months earlier. 2. The dose-response curves were obtained at rest and during repeated bouts of supine bicycle exercise. The cumulative dose amounted to 0.024 mg/kg body weight for pindolol and to 0.192 mg/kg body weight for propranolol. 3. At rest propranolol significantly reduced heart rate and cardiac output by 12% and 15% respectively. Arterial mean blood pressure was reduced by 9.2 mmHg. Mean pulmonary artery pressure increased significantly by 2 mmHg. Statistically significant changes in these variables were not seen after pindolol or placebo. 4. During exercise pindolol and propranolol both reduced cardiac output, heart rate and arterial blood pressure to the same extent. After propranolol mean pulmonary artery pressure was increased significantly by 3.6 mmHg. Pindolol and placebo did not change pulmonary artery pressure significantly. 5. The study suggests that pindolol may offer haemodynamic advantages over beta-receptor-blocking agents without intrinsic sympathomimetic activity during low activity of the sympathetic nervous system, and may be preferable in situations where the beta-receptor-blocking effect is required only during physical or psychic stress.