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Biomedical subjects

S Friman

Publications and source records attributed to S Friman.

At least 91 records · Page 5Linked to original sources

Liver transplantation in familial amyloidotic polyneuropathy. Follow-up of the first 20 Swedish patients.

Familial amyloidotic polyneuropathy (FAP) is an inherited fatal form of amyloidosis caused by mutant transthyretin. The disease is characterized by progressive peripheral and autonomic neuropathy. Most of the transthyretin is produced by the liver, and we have shown previously that the metabolic deficiency can be corrected by liver transplantation. In the present study, the clinical results from the first 20 patients who underwent liver transplantation for FAP in Sweden are evaluated. Three of the patients suffered from renal failure and underwent a simultaneous kidney transplantation. Fourteen of the 20 patients (70%) are alive 10-52 months after transplantation. The patients' nutritional status at the time of transplantation had a significant impact on mortality and morbidity (P < 0.007). Long-standing disease was another negative prognostic factor (P < 0.02). One year after transplantation, the nutritional status had improved (P < 0.02). Improvements were also noted in walking capacity and for gastrointestinal and urogenital symptoms. The results show that liver transplantation offers an effective means to treat patients with FAP. The procedure should preferably be performed before the nutritional status is poor and advanced organ dysfunction has developed.

Adult↗

The ATP/ADP binding domains of actin are conserved in nucleosome complexed with histone H1 and high mobility group-17 protein.

Chromatin has been proposed to share a common evolutionary origin and analogous mechanisms of action with various structures of cytoskeleton such as actin filaments. ATP has been shown to facilitate chromatin remodelling, but the exact site of its interaction with chromatin has not been elucidated. The facts, that ATP binds specifically to actin and promotes its polymerization, led us to characterize the possible domains involved in ATP binding in nucleosome. Comparison of the sequences of actin and the protein components of nucleosome suggests that H2A may contain an adenosine binding site similar to the adenosine motif of actin, H1 and/or H2B phosphate/Ca2+ binding sites corresponding to the phosphate 1 motif of actin, HMG17 a phosphate/Ca2+ binding site corresponding to the phosphate 2 motif of actin. The ability to bind ATP may be involved in the organization of chromatin into inactive solenoid-like structures in vivo.

Actins↗

Influence of liver transplantation and cyclosporin on bile secretion--an experimental study in the rat.

Bile secretion is reduced after liver transplantation. It has been suggested that this is due either to the effect of cyclosporin or to the damage to the liver graft during preservation and reperfusion. The aim of this study was to explore the influence of cyclosporin as well as of liver transplantation on bile secretion. Bile flow was studied in an experimental model in the rat. In syngeneic liver-transplanted animals, the bile flow was increased compared to the bile flow in the control group (1.29 +/- 0.09 ml/h vs 0.66 +/- 0.03 ml/h; P < 0.01), mainly due to an increased bile acid-independent flow (0.76 ml/h vs 0.50 ml/h; P < 0.01). The findings in the liver-transplanted rats contrasted with those in a group of nontransplanted animals treated with cyclosporin. Cyclosporin treatment resulted in a reduced bile acid-independent fraction (0.37 ml/h vs 0.50 ml/h, P < 0.05) of the bile flow, although no biochemical signs of hepatotoxicity were present. This reduction in the bile acid-independent fraction could, however, not be demonstrated when cyclosporin was given to a group of liver-transplanted rats, although a reduced total bile flow was recorded in the 1st hour measurements. In contrast to previous studies, we found that the cyclosporin vehicle (Cremophor EL), when administered chronically, induced a higher bile flow than that in the control rats. This effect was not seen in the transplanted rats. Our findings in this experimental rat model indicate that cyclosporin will influence and reduce bile secretion and bile acid secretion even if no other signs of liver dysfunction are present. On the other hand, the preservation and reperfusion in this model resulted in an increased bile flow, while bile acid secretion remained constant.

Animals↗

Hepatocyte and Kupffer cell function after liver transplantation in the rat--in vivo evaluation with dynamic scintigraphy.

In vivo physiological measurements of hepatocyte and Kupffer cell function after liver transplantation are desirable. Orthotopic liver transplantation was performed in 54 rats. Hepatocyte and Kupffer cell function were measured with dynamic liver scintigraphy. Hepatic clearance of 99mTc-Nanocoll (%/min), an albumin colloid phagocytosed by the Kupffer cells, was used to evaluate Kupffer cell function. Hepatic clearance of 99mTc-IODIDA (%/min), an imino-diacetic-acid taken up and secreted by the hepatocytes, was used to evaluate the hepatocyte function. Hepatic clearance in control rats was 27 +/- 2%/min for Nanocoll and 30 +/- 3 %/min for IODIDA. After syngenic liver transplantation, without rejection, there was a rise in Nanocoll clearance (34 +/- 2 %/min p < 0.01) after 3 weeks, but no change in IODIDA clearance (32 +/- 3 %/min N.S.). After syngenic liver transplantation with preservation time prolonged to 16 h, there were no changes in IODIDA or Nanocoll clearance 1 day after transplantation. Both IODIDA (11 +/- 2 %/min) and Nanocoll clearance (22 +/- 2 %/min) were decreased (p < 0.001) during rejection after allogenic transplantation. An in vivo method of measuring the hepatocyte and Kupffer cell function in the transplanted liver is described. Kupffer cell function was increased after syngenic liver transplantation. Kupffer cell and hepatocyte function were decreased during rejection. Dynamic liver scintigraphy seems a suitable procedure for examining liver injury after liver transplantation in the experimental setting.

Alanine Transaminase↗

Medication with ursodeoxycholic acid enhances the biliary clearance of polyethylene glycol 900, but not mannitol.

Ursodeoxycholic acid (UDCA) is a nontoxic bile acid currently used in the treatment of different cholestatic diseases. This bile acid is also considered to be a 'hypercholeretic bile acid'. The effects of daily administration of UDCA on bile flow and the bile acid secretion rate in man are not fully known. The aim of this study was to explore the effects by UDCA on bile flow and its different functions. The biliary clearances of polyethylene glycol 900 (PEG 900) and mannitol were measured simultaneously in patients with an indwelling T tube after cholecystectomy. One group (n = 6) were given UDCA (10 mg/kg/day) for at least 14 days before the investigation and a control group (n = 8) received no bile acid treatment. The bile secretion was studied in acute experiments where bile was drained for 6 h. The bile plasma ratio for PEG 900 was 31 and that for mannitol was 0.7 which corresponds well with the results obtained in different animal species. The relationship between bile flow and the bile salt secretion rate, as expressed by linear regression analysis, showed no difference between the 2 groups (control y = 0.22 + 0.012x, r = 0.61, p < 0.001; UDCA y = 0.20 + 0.016x, r = 0.88, p < 0.001). The relationship between the biliary clearance of PEG 900 and the bile salt secretion rate, as expressed with linear regression analysis, showed a significantly steeper slope for the UDCA-treated patients (control y = 8.1 + 0.34x, r = 0.41, p < 0.05; UDCA y = 5 + 1.58x, r = 0.78, p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Role of nitric oxide in motility and secretion of the feline hepatobiliary tract.

BACKGROUND: Nitric oxide (NO) mediates inhibition of gastrointestinal smooth-muscle cells via nonadrenergic, non-cholinergic (NANC) nervous pathways. The effect of NO on the absorption and secretion by the mucosa of the gastrointestinal and hepatobiliary tracts is less well known. The aim of this study was to evaluate the effects of a pharmacologic blockade of NO synthase on sphincter of Oddi activity, gallbladder function, and bile secretion and to demonstrate the presence of NO synthase-positive neurons in this region. METHODS: Experiments were conducted on anesthetized cats after blockage of noradrenergic and cholinergic neurotransmission. Flow resistance in the sphincter of Oddi, gallbladder fluid absorption and motility, bile outflow from the liver, and bile salt secretion were registered. RESULTS: Flow resistance exerted by the sphincter of Oddi increased dose-dependently in response to the NO synthase blocker NG-nitro-L-arginine. The increase in flow resistance was reversed stereospecifically by L-arginine, the substrate for NO synthesis. No significant effects on bile secretion, gallbladder fluid transport, or gallbladder motility were observed. NO synthase-positive neurons were identified close to the sphincter of Oddi and in the gallbladder mucosa. CONCLUSIONS: This tonically active inhibitory NANC innervation of the sphincter of Oddi may be important in the physiologic regulation of the bile duct pressure.

Animals↗

Inflammation reduces mucosal secretion of hydrogen ions and impairs concentrating function and luminal acidification in feline gallbladder.

BACKGROUND: The gallbladder mucosa normally absorbs fluid and secretes H+ ions. The fluid secretion in inflamed gallbladders is induced by prostaglandins and mediated by intramural vasoactive intestinal peptide (VIP)-ergic nerves. METHODS: The influence of inflammation on gallblader contents due to secretion of H+ into the lumen. In animals with inflamed gallbladder this acid secretion was reduced; there was secretion of HCO3- and no evident acidification of the gallbladder contents. Injection of VIP antiserum or indomethacin restored H+ secretion and inhibited HCO3- and fluid secretion by the inflamed gallbladder mucosa. An impaired acidification of the gallbladder contents due to mucosal inflammation may reduce the solubility of calcium salts in gallbladder bile and increase the risk of their precipitation in the lumen. CONCLUSION: Mucosal inflammation reduces H+ secretion and impairs acidification of the gallbladder contents.

Amiloride↗

Spectrum of hereditary renal disease in a kidney transplant population.

Re-evaluation of the underlying renal disease in 1000 consecutive kidney transplant patients revealed 129 cases of adult autosomal dominant polycystic kidney disease and 60 clear and seven suspected cases with other hereditary renal disorders. Twenty-four of 60 patients had cystic/dysplastic disease--10 of these classified as nephronophthisis, five as polycystic disease, and nine with the renal affection as part of a congenital malformation syndrome. Thirteen patients had Alport's syndrome, nine were diagnosed with tubulointerstitial nephritis, and six had an adult form of focal segmental glomerular sclerosis (FSGS). Two had changes classified as nephrosclerosis, but with an autosomal dominant mode of inheritance. Finnish type congenital nephrotic syndrome was present in two children and familial amyloidosis in two adults. Two patients had an unclassified disease. During follow-up, five patients with cystic/dysplastic disorders manifested liver disease. None of the patients with FSGS had recurrence and none of the Alport patients had anti-GBM disease. There were no other complications related to the renal condition. In conclusion, hereditary disorders are underestimated in regular registries of patients with end-stage renal failure. An adult form of FSGS and what seems to be a hereditary form of nephrosclerosis are among those that merit further study.

Adolescent↗

Complement system activation during orthotopic liver transplantation in man. Indications of peroperative complement system activation in the gut.

Sixteen patients with acute and chronic liver disease undergoing OLT were studied regarding the role of the liver and the gut in complement activation. Also, the relation between complement activation and clinical manifestations during the liver transplantation reperfusion period was investigated. Blood samples for measurement of complement anaphylatoxin C3a (C3a), complement anaphylatoxin C5a (C5a), and terminal C5b-9 complement complex (TCC) were taken simultaneously from the central venous catheter and the radial arterial line before starting the operative procedure, 1 min before declamping, and 1-2 min, 5 min, 30 min and 6-12 hr after declamping. Simultaneous blood sampling from the radial arterial line, central venous catheter, portal vein, and hepatic vein was performed 1-2 min and 5 min after completed unclamping. Elevated plasma levels of C3a and TCC were found upon reperfusion, while C5a levels remained unchanged throughout the operation compared with the preoperative levels. The levels of C3a in the portal vein were higher compared with the levels in the simultaneously obtained samples from the radial artery. The results indicate complement cascade activation located to the gut during the reperfusion phase of OLT. Seventy-five percent of the patient studied suffered from the postreperfusion syndrome, indicated by profound hypotension upon reperfusion of the transplanted liver. There was a significant correlation between high concentration of C3a anaphylatoxin and development of profound hypotension.

Adult↗

VIP-antiserum inhibits fluid secretion by the inflamed gallbladder mucosa.

The inflammatory fluid secretion by the gallbladder mucosa in experimental cholecystitis is induced by an increased prostaglandin formation and is mediated by intramural nerves. In the present study the effect of VIP-antiserum on the inflammatory fluid secretion in the gallbladder was tested in a validated experimental model in cats. The animals were studied in acute experiments 6 weeks after a procedure when the cystic duct was tied and gallstones were implanted in the gallbladder. During basal conditions there was a continuous secretion of fluid into the lumen of the inflamed gallbladder averaging 0.43 +/- 0.18 ml/h. Injection of VIP antiserum, obtained from immunized rabbits and diluted with saline 1:10 in a bolus of 4 ml into the coeliac artery reversed this secretion into an absorption of 1.72 +/- 0.44 ml h-1 (P < 0.001). VIP-antiserum did not affect the fluid adsorption in control animals with an intact gallbladder and injection of control serum from rabbits not immunized to VIP did not affect fluid secretion in the inflamed gallbladders. The results support the idea that the inflammatory fluid secretion in the gallbladder mucosa is mediated by VIP-ergic nerve fibres.

Animals↗

Glomerular filtration rate after liver transplantation with a low-dose cyclosporin protocol.

Cyclosporin nephrotoxicity is a well-known complication in organ transplantation. In successful liver transplantation, a moderate degree of renal impairment is accepted. Whether this impairment is continuously progressive, stabilizes with time, or is reversible is not known. We have prospectively evaluated the glomerular filtration rate (GFR) using 51CrEDTA plasma clearance in 29 liver transplant patients (11 males and 18 females) with a mean age of 49 years (range 22-62 years). The 51CrEDTA plasma clearance measurements were performed preoperatively and at 3, 6, 12, 24, and 36 months after the liver transplantation. All but six patients were given sequential, quadruple drug therapy with antithymocyte globulin, azathioprine, steroids, and cyclosporin. Intravenous cyclosporin was avoided and oral cyclosporin started when renal function was stable. Cyclosporin was started in a dose of 8 mg/kg body weight, aiming at whole blood through levels (specific monoclonal technique) of 200 micrograms/l in the postoperative period; thereafter, the dosage was rapidly tapered down, aiming at whole blood trough levels of less than 100 micrograms/l at 3 months (1.5-2 mg/kg body weight). From a mean preoperative GFR of 89 +/- 3 ml/min per 1.73 m2, all patients declined in renal function after transplantation to a mean of 64 +/- 4 ml/min per 1.73 m2 3 months after transplantation, and starting in the 3rd month the renal function was stable at about 70% of the preoperative value. No correlations were found between cyclosporin peak level or accumulated cyclosporin dose and renal impairment. We conclude that liver transplantation with cyclosporin immunosuppression will induce renal impairment even if cyclosporin blood levels are carefully monitored and kept low.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Raised pressure in the bile ducts after orthotopic liver transplantation.

Biliary complications are common after orthotopic liver transplantation. Bile leakage in the immediate postoperative period and on removal of the T-tube could possibly be caused by a raised bile duct pressure. In order to test this hypothesis, bile duct pressure was studied in seven consecutive liver transplant patients. During the operation, the common bile duct was anastomosed end-to-end over a T-tube. The initial bile duct pressure measurement was performed a median of 12 days (range 10-17 days) after the transplantation and on one or two more occasions during the following 3 months. Seven cholecystectomized gallstone patients with indwelling T-tubes were used as controls. The bile duct pressure at the level of the xiphoid process in the transplanted group was 7.7 +/- 1.4 cm H2O and in the control group 0.5 +/- 0.8 cm H2O (P < 0.001). The initially increased bile duct pressure after liver transplantation decreased with time (P < 0.05) towards normal during the following 3 months. The raised pressure may increase the risk of bile leakage in the postoperative period.

Adult↗

A possible role of ursodeoxycholic acid in liver transplantation.

There are many different causes of graft dysfunction and cholestasis after liver transplantation. These include non-primary function, preservation and reperfusion injury, acute rejection, artery thrombosis, drug toxicity, bile leakage, and bile duct stenosis. Medication with ursodeoxycholic acid (UDCA) has beneficial effects in different cholestatic conditions. The initial rationale for its use after liver transplantation was to alter the bile acid pool to a more atoxic composition, as liver transplantation can be associated with cholestasis and can stimulate the initial bile production. We have consecutively treated 41 patients with primary graft function with UDCA. During the first postoperative month, 17% of the UDCA treated patients had an episode of acute rejection compared with 75% of a historical control group of 8 patients. The results suggest that adjuvant treatment with UDCA reduces acute liver graft rejection. This has to be confirmed by controlled prospective trials; one is presently being carried out in the Nordic countries. Several studies have indicated an immunomodulating capacity of this bile acid and we have recently reported our results from a heart transplant model in the rat, where treatment with UDCA prolonged graft survival. Improvement in surgical technique and postoperative care as well as immunosuppressive treatment has improved the results of liver transplantation. Acute rejection is nowadays a dominating problem after liver transplantation and the inclusion of UDCA may reduce morbidity.

Animals↗

Hepatic excretion and metabolism of polyethylene glycols and mannitol in the cat.

The biliary clearances of fluid phase markers like erythritol and mannitol have been used to estimate canalicular bile flow. Larger fluid phase marker molecules like polyethylene glycol (PEG) 900 are excreted more extensively into bile, and it has been suggested that the biliary clearance of these give a more accurate measure of canalicular water flux than those of erythritol and mannitol. In this study, the biliary excretion of PEG 900 was compared with that of mannitol during choleresis induced by either sodium taurocholate or secretin. The biliary excretion of PEG 900 exceeded that of mannitol by a factor of 94. The biliary clearance of these markers was not influenced by secretin-induced choleresis. Using ion-exchange chromatography and fast atom bombardment mass spectrometry (FABMS) it was demonstrated that 26% of the PEG molecules are excreted into bile after oxidation to carboxylic acids, whereas sulphate conjugation is negligible. The majority of the PEG molecules (74%) were secreted unchanged, which supports the hypothesis of a mainly passive movement of PEG with the water flux into bile. FABMS showed an enrichment of larger PEG molecules in bile, which supports a previous finding that among differently sized PEGs the 1074-Da molecules have the highest biliary excretion.

Animals↗