Flux of selected body fluid constituents and benzylpenicillin in polyacrylamide hydrogel (PAAG)

The polyacrylamide hydrogel (PAAG) Aquamid® (Contura International A/S Soeborg, Denmark) is one of the new macromolecules that are used as implants and tissue fillers in reconstruction and aesthetic surgery. This study showed, by means of radioactive isotope methods, that PAAG can exchange both physiological and non-physiological constituents very efficiently with the surrounding medium. The efflux (J, mole/(cm(2)× s), 25 °C, pH 7.2) of water (4.4 × 10(-5) ), chloride (2.4 × 10(-7) ), urea (1.0 × 10(-9) ), and glucose (1.1 × 10(-9) ) was 3-40x greater than in human red blood cells. PAAG was also accessible to sucrose, inulin, and benzylpenicillin that could not permeate biological cell membranes. The conclusion of the study is that the hydrogel structure created no significant barrier to the exchange of solvent and solutes with the surrounding medium.

Combined Liver and Kidney Transplantation in a Multicenter Transplantation Program in Chile

INTRODUCTION

Combined liver and kidney transplantation (CLKT) is an exceptional therapeutic procedure limited to a few diseases with advanced compromise of these organs. Hyperoxaluria type I and polycystic disease are the most frequent indications. The aim of this article was to report our indications and results of CLKT in a multicenter transplantation program in Chile.

MATERIAL AND METHODS

Our Excel database was reviewed to select patients who were treated with CLKT between 1993 and July 2004.

RESULTS

Among 242 liver transplantations (LT) and 48 kidney transplantations (KT), 7 were CLKT, representing 2.8% of LT and 14.5% of KT. Four patients were women and 3 were male of average age 46.8 years. One patient was a child. Most frequent indications were chronic renal failure associated with terminal liver disease and polycystic disease. One patient needed liver retransplantation due to hepatic vein thrombosis. One patient had a biliary fistula and another had a urinary fistula, treated conservatively. Acute liver rejection took place in 3 cases, 1 of which required antibodies. Two patients died, 1 due to aspergillosis and the other due to vascular complications in the transplanted liver. Actuarial survival rates were 71.4% at 1 and 5 years. Chronic renal failure is not a contraindication to LT.

CONCLUSION

CLKT is an acceptable option for these patients.

ABO-incompatible liver transplantation: a new therapeutic option for patients with acute liver failure in Chile

Different ways have been suggested to expand donor numbers for liver transplantation. Transplantation using ABO-incompatible hepatic grafts has recently been a controversial issue due to the high risk of hyperacute rejection mediated by preformed anti-ABO antibodies. We report three patients with acute liver failure who were transplanted with ABO-incompatible livers: A to O in two patients and A to B in one case. We used pre- and posttransplant total plasma exchange, splenectomy, and triple immunosuppression. All three patients are alive; one graft was lost, probably secondary to thrombotic microangiopathy with low isohemagglutinin titers of 1:8. One patient developed acute cellular rejection that was reversed with a bolus of methylprednisolone. No antibody-mediated rejection occurred. Financial and infectious considerations have to be considered. In our series, the final liver transplantation cost was higher than average for acute liver failure. Plasmapheresis has the highest cost of all the additional procedures. ABO-incompatible liver transplantation, because of the splenectomy it requires, has been associated with more infections due to encapsulated organisms. However, with splenectomy in our three patients, none had infections due to these bacteria. In our country, we do not consider ABO-incompatible liver transplantation as a first-line option, except for highly selected patients.

[Chronic hepatitis C and celiac sprue: an infrequent association]

Celiac sprue (CS) has been described in association with hepatitis C virus (HCV) as another immunologic manifestation of this infectious disease. We report 2 patients, a 42-year-old woman and a 59-year-old man, with chronic HCV hepatitis. Upper digestive endoscopy and duodenal biopsy were performed to investigate diverse symptoms. The results of histological analysis and serological study were compatible with CS. The association between both diseases, including immunological aspects and the implications of anti-HCV treatment, is discussed.

Outcomes of orthotopic liver transplantation in Chile

Our liver transplant program was started in 1993 in a private clinic and a public hospital. Thereafter, a rapid increase in adults and pediatric candidates for this therapeutic option lead to this analysis of results in 165 orthotopic liver transplants (OLT) in 143 patients between November 1993 and December 2002. Seventy-four OLT were performed in 66 adult patients and 91 in the pediatric group. Liver grafts came from cadaveric donors in 145 cases (74 adults and 71 children). The technique of living-related donor was utilized in 20 pediatric cases. Main indications for OLT in the adult group were HCV cirrhosis, primary biliary cirrhosis; biliary atresia and acute liver failure were the indications in pediatric patients. Retransplantation was needed for 23 patients, including 9 adults and 14 children. The most frequent causes of death were sepsis, graft primary nonfunction, and vascular complications. Actuarial survivals at 1 and 5 years were 80.7% and 72.6% for the adult group and 82% and 74.8% for the pediatric group, respectively. Our results are comparable to those published by large, experienced, international centers, with much better financial support.

Adrenergic receptors, Na+/H+ exchange and volume regulation in lungfish erythrocytes

Aestivation in African and South American lungfish (Protopterus and Lepidosiren, respectively) is associated with elevations of extracellular osmolarity. Osmotic shrinkage of Protopterus red blood cells (RBCs) caused a small but significant stimulation of the Na influx that was amiloride-sensitive. suggesting involvement of the Na+/H+ exchanger (NHE). The associated in vitro regulatory volume increase was insignificant within a time frame of 120 min, but the shrinkage-activated Na+ influx may be sufficient for slow regulatory volume increase during aestivation in vivo. Osmotic swelling of the RBCs induced an incomplete regulatory volume decrease that was statistically significant after 180 min. The RBCs of Protopterus were very large (mean cellular volume of 6939 +/- 294 microm3) and possessed 23,066 +/- 7,326 beta-adrenoceptors cell(-1) with a Kd value of 6.1 +/- 3.2 nM. The number of receptors per unit surface area of lungfish RBCs was calculated to be twice that of trout RBCs and 70% that of cod RBCs. There was, however, no adrenergic stimulation of the NHE in either Protopterus or Lepidosiren. Acidification of the extracellular medium also failed to activate the NHE.

Acute and chronic influence of temperature on red blood cell anion exchange

Unidirectional (36)Cl(−) efflux via the red blood cell anion exchanger was measured under Cl(−) self-exchange conditions (i.e. no net flow of anions) in rainbow trout Oncorhynchus mykiss and red-eared freshwater turtle Trachemys scripta to examine the effects of acute temperature changes and acclimation temperature on this process. We also evaluated the possible adaptation of anion exchange to different temperature regimes by including our previously published data on other animals. An acute temperature increase caused a significant increase in the rate constant (k) for unidirectional Cl(−) efflux in rainbow trout and freshwater turtle. After 3 weeks of temperature acclimation, 5 degrees C-acclimated rainbow trout showed only marginally higher Cl(−) transport rates than 15 degrees C-acclimated trout when compared at the same temperature. Apparent activation energies for red blood cell Cl(−) exchange in trout and turtle were lower than values reported in endothermic animals. The Q(10) for red blood cell anion exchange was 2.0 in trout and 2.3 in turtle, values close to those for CO(2) excretion, suggesting that, in ectothermic animals, the temperature sensitivity of band-3-mediated anion exchange matches the temperature sensitivity of CO(2) transport (where red blood cell Cl(−)/HCO(3)(−) exchange is a rate-limiting step). In endotherms, such as man and chicken, Q(10) values for red blood cell anion exchange are considerably higher but are no obstacle to CO(2) transport, because body temperature is normally kept constant at values at which anion exchange rates are high. When compared at constant temperature, red blood cell Cl(−) permeability shows large differences among species (trout, carp, eel, cod, turtle, alligator, chicken and man). Cl(−) permeabilities are, however, remarkable similar when compared at preferred body temperatures, suggesting an appropriate evolutionary adaptation of red blood cell anion exchange function to the different thermal niches occupied by animals.

Small bowel motility in primary biliary cirrhosis

OBJECTIVE

Previous studies have shown small bowel motor activity abnormalities in patients with liver cirrhosis of different etiologies, but motility has not been studied in patients with primary biliary cirrhosis. Our aim was to investigate proximal small bowel motility in these patients.

METHODS

Twenty-five female patients presenting clinical, biochemical, serological, and histological findings compatible with primary biliary cirrhosis, 10 female patients with nonalcoholic liver cirrhosis, and 10 normal female controls were studied. Motility of the upper small bowel was measured in the fasted state by means of perfused manometric catheters, connected to external transducers and positioned in the small bowel under fluoroscopy.

RESULTS

The average amplitude of contractions was significantly decreased in patients with primary biliary cirrhosis compared with other liver cirrhosis (20.2+/-1.0 vs 32+/-2.9 mm Hg). Also, a significantly increased frequency of cluster of contractions and an increased duration of phase II of the migrating motor complex as seen in liver cirrhosis was observed when compared with normals.

CONCLUSION

We conclude that primary biliary cirrhosis patients present motor abnormalities of the small intestine similar to those of patients with liver cirrhosis of other etiologies. In addition, a decrease in the amplitude of small bowel contractions was also found in these patients, suggesting a myogenic involvement.

[Prevalence and genotypes of hepatitis C virus in blood donors and in patients with chronic liver disease and hepatocarcinoma in a Chilean population]

BACKGROUND

The impact of hepatitis C virus infection in Chile has not been well established.

AIM

To assess hepatitis C virus infection in normal Chileans and in patients with liver disease.

SUBJECTS AND METHODS

Antibodies against hepatitis C virus were investigated in 21,000 blood donors, 133 patients with non alcoholic chronic liver disease and in 50 patients with hepatocarcinoma. Viral RNA was studied by polymerase chain reaction in all positive blood donors, in 51 patients with chronic liver disease and in all patients with hepatocarcinoma. Hepatitis C virus genotype was established using restriction fragment length polymorphism in 118 RNA positive samples.

RESULTS

In blood donors, a 0.3% prevalence of positive antibodies was found. The figure for chronic liver disease was 53% and for hepatocarcinoma, 48%. Viral RNA was detected in 100% of patients with chronic liver disease and hepatocarcinoma and in 68% of blood donors with positive antibodies. Genotype 1b was identified in all infected patients with hepatocarcinoma, in 86% of patients with chronic liver disease and in 46% of blood donors.

CONCLUSIONS

Hepatitis C virus infection is an important etiologic agent for chronic liver disease in Chile. The predominance of genotype 1b among patients with the most severe form of liver disease is in agreement with observations made abroad.

Carbon dioxide transport in alligator blood and its erythrocyte permeability to anions and water

Deoxygenation of alligator red blood cells (RBCs) caused binding of two HCO3- equivalents per hemoglobin (Hb) tetramer at physiological pH. At lowered pH, some HCO3- binding also occurred to oxygenated Hb. The erythrocytic total CO2 content was large, and Hb-bound HCO3-, free HCO3-, and carbamate contributed about equally in deoxygenated cells. The nonbicarbonate buffer values of RBCs and Hb were high, and the Hb showed a significant fixed acid Haldane effect. Binding of HCO3- on deoxygenation occurred without a change in RBC intracellular pH, revealing equivalence between oxylabile HCO3- and H+ binding. Erythrocyte volume, plasma pH, and plasma HCO3- concentration also varied little with the degree of oxygenation. Diffusional water permeability was higher in oxygenated than deoxygenated RBCs. The RBCs have rapid band 3-mediated Cl- and HCO3- transport, which was not affected by degree of oxygenation, but net fluxes of Cl- and HCO3- via the anion exchanger are small during blood circulation at rest. Most of the CO2 taken up into the blood as it flows through tissue capillaries is carried within the erythrocytes as Hb-bound HCO3- until CO2 is excreted when blood flows through pulmonary capillaries.

The combination of ursodeoxycholic acid and methotrexate for primary biliary cirrhosis is not better than ursodeoxycholic acid alone

BACKGROUND/AIMS

Many therapies have been tried in primary biliary cirrhosis. It has been suggested that a combination of ursodeoxycholic acid and methotrexate may offer advantages. Because the benefit and safety of this combination is uncertain, we conducted this prospective, randomized, double-blind, controlled trial.

METHODS

Twenty-five patients with well-defined primary biliary cirrhosis were randomly assigned to receive either ursodeoxycholic acid (500 mg/day) plus methotrexate (10 mg/week) or ursodeoxycholic acid plus placebo for a period of 48 weeks. Clinical, biochemical and histologic evolution were assessed.

RESULTS

In both groups the clinical response was similar and heterogeneous. In patients of ursodeoxycholic acid alone group, biochemical and histologic changes were comparable to those of patients of ursodeoxycholic acid plus methotrexate at 48 weeks. The addition of methotrexate was not associated with substantial adverse affects.

CONCLUSIONS

The use of methotrexate in combination with ursodeoxycholic acid was not followed by an additive benefit over ursodeoxycholic acid alone, nor was substantial toxicity added. Unless larger and longer controlled trials with clinical, biochemical and histologic controls show it to be a safe and effective therapy for primary biliary cirrhosis, ursodeoxycholic acid+methotrexate should not be used as a proven and accepted treatment.

Orthotopic liver transplantation improves small bowel motility disorders in cirrhotic patients

Altered small intestinal motility has been observed in patients with liver cirrhosis. Its pathophysiology remains to be defined. Our aim was to investigate the effect of orthotopic liver transplantation on small intestinal dysmotility in patients with liver disease. Two patients were studied both before and after orthotopic liver transplantation. Abnormal migrating motor complex activity and prominent clustered contractions present preoperatively normalized within 6 months after the surgical procedure. This finding might represent an additional benefit of liver transplantation considering that altered motility may be involved in bacterial overgrowth and infections observed in these patients.

Kinetics of bicarbonate transport in human red blood cell membranes at body temperature

We studied unidirectional [14C]HCO3- efflux from human resealed red cell ghosts with 1 mM acetazolamide under self-exchange conditions at pH = pH(i = o) 7.4-9.0 and 0-38 degrees C by means of the Millipore-Swinnex and continuous flow tube filtering techniques. 14CO2 loss from cells to efflux medium and further to the atmosphere was insignificant. [14C]HCO3- efflux was determined at pH 7.8, 38 degrees C under symmetric variation of the HCO3- concentrations (C(i = o)), and asymmetric conditions: C(i) varied, C(o) constant, or C(o) varied, C(i) constant. MM-fit, Jeff = Jmaxeff x C x (C + K1/2)-1, used to describe the concentration dependence of Jeff,o when only C(o) varied, yields at C(i) = 50 mM: K1/2o = 3.8 mMJ, Jmaxeff.o = 20 nmol cm-2 s-1; at C(i) = 165 mM: K1/2o = 10 mM, Jmaxeff.o = 32 nmol cm-2 s-1. When C(i) varied, noncompetitive self inhibition by HCO3- binding (inhibitor constant K1) to an intracellular site was included (MS-fit). Under conditions of (a) symmetry: C(i = o) = 9-600 mM, K1/2s = 173 mM, K1 = 172 mM, and Jmaxeff,s = 120 nmol cm-2 s-1, (b) asymmetry: C(o) = 50 mM, K1/2i = 116 mM, K1 = 136 mM, and Jmaxeff,i = 92 nmol cm-2 s-1. All flux parameters accord with the ping-pong model for anion exchange. The data for C(i) < 200 mM also fit well to the MM equation, but K1/2 and Jmaxeff are different from the MS-fit and are inconsistent with the ping-pong model. Thus, self-inhibition (MS-fit) must be included even at low concentrations. As at 0 degree C, the system is asymmetric: 8-10 times more unloaded transport sites face inward than outward when C(i = o). Jeff,s was not mono-exponentially dependent on temperature at 0-38 degrees C, indicating that the transmembrane anion transport is controlled by several rate constants with different temperature dependencies. Jeff,s was not significantly affected by increasing pH(i = o) from 7.4 to 7.8, but it decreased by 50% when pH was raised to 9.0.

The asymmetry of chloride transport at 38 degrees C in human red blood cell membranes

Band 3-mediated Cl- exchange in human red blood cells and resealed ghosts was measured at 38 degrees C by the continuous flow tube method. When external Cl- concentration, C(o), is varied with constant internal Cl- concentration, C(i), the flux fits a simple Michaelis-Menten saturation curve (MM fit), with K1/2o = 3.8 +/- 0.4 mM. When the Cl- concentration is varied simultaneously at both sides of the membrane in resealed ghosts (C(i) = C(o) = C(i = o)), the flux rises toward a flat maximum between 200 and 450 mM Cl-, and then decreases at very high C(i = o). An MM fit to the data with C(i = o) < 500 mM gives K1/2s of 106 +/- 13 mM; fits including modifier site inhibition (MS fit) give an over threefold higher K1/2s. Despite this uncertainty, the intrinsic asymmetry of unloaded transport sites, A (defined as E(o)/E(i) with C(i) = C(o), where E(i) is the fraction of unloaded inward-facing sites and E(o) is the fraction of unloaded outward-facing sites), calculated from K1/2s and K1/2o, ranges only from 0.046 to 0.107. A new method, which uses the initial slope of a plot of Cl- flux versus C(i = o), gives A values of 0.023 to 0.038. Flufenamic acid (FA) inhibits Cl- exchange by binding to an external site different from the transport site. At 38 degrees C, FA binds 24-36 times more tightly to E(o) than to E(i). Estimates of A from FA inhibitory potency range from 0.01 to 0.05. All methods, including bicarbonate data from the preceding paper, indicate that at 38 degrees C, like 0 degree C, far more band 3 molecules are in the E(i) than in the E(o) form. The agreement of various methods supports the ping-pong model for anion exchange, and demonstrates that the intrinsic asymmetry is very slightly, if at all, affected by temperature.

[Hepatic veno-occlusive disease associated to the use of azathioprine in a renal transplant recipient]

We report a 30 years old male, recipient of a kidney allograft and treated with azathioprine, who eighteen days after transplantation had a clinically asymptomatic elevation of total bilirubin and alkaline phosphatases. Nineteen months later, he presented with mild ascites, with a total bilirubin of 3.5 mg/dl, alkaline phosphatases of 308 U/L (normal < 170 U/L) and a prothrombin time at 55% of control. A liver biopsy showed sinusoidal and perivenular fibrosis without inflammation, compatible with chronic venous obstruction. Hepatic veno-occlusive disease is an infrequent complication of azathioprine use.

[Hepatitis E virus infection in Chile: preliminary report]

BACKGROUND

Hepatitis E virus is an enterally transmitted virus that produces an acute self limited infection.

AIM

To study serum antibodies against hepatitis E virus in different patients.

PATIENTS AND METHODS

Using and ELISA technique, IgG antibodies against hepatitis E virus were measured in 40 alcoholics, 40 hemophiliacs, 174 blood donors, 36 subjects with acute non A-non B-non C hepatitis and 66 subjects with acute hepatitis A.

RESULTS

Antibodies were detected in one alcoholic (2.5%), 3 hemophiliacs (7.5%), 7 blood donors (4%), 3 patients with non A-non B-non C hepatitis (8.3%) and 3 patients with acute hepatitis A (4.5%).

CONCLUSIONS

A low frequency of hepatitis E infection was detected in the studied subjects.

The transport of phosphate between the plasma and dialysate compartments in peritoneal dialysis is influenced by an electric potential difference

Six kinetic models of transperitoneal phosphate transport were formulated and validated on the basis of experimental results obtained from 22 non-diabetic patients undergoing peritoneal dialysis. The models were designed to elucidate the presence or absence of diffusive, non-lymphatic convective, and lymphatic convective phosphate transport. Calculations allowed for a 20% protein binding of phosphate. The validation procedure demonstrated that only diffusive and non-lymphatic convective phosphate transport mechanisms were identifiable. A lymphatic convective phosphate transport mechanism was not identifiable. Furthermore, it was demonstrated that the electrochemical gradient between plasma water and dialysate favours the diffusive phosphate transport, and both electric and chemical potentials must be taken into account in calculations of the transperitoneal phosphate transport.

Antimitochondrial antibody detection by indirect immunofluorescence on mouse sperms

Antimitochondrial antibodies (AMA) are characteristically present in the serum of patients with primary biliary cirrhosis (PBC). AMA detection constitutes an important step for the clinical diagnosis of PBC, the indirect immunofluorescence against cryostat sections of rat of mouse organs being the most common method used. This study presents an alternative method for AMA detection by indirect immunofluorescence using mouse sperms as substrate. Sera of 17 patients with PBC were examined for AMA using mouse sperms and frozen sections of rat kidney. With mouse sperms as substrate, all PBC sera were found to be AMA positive showing an intense fluorescent reaction on the mitochondrial sheath of mouse sperms (100% sensitivity). No false positive results were obtained with normal sera. Sera of 22 patients with collagen diseases (systemic lupus erithematosus and progressive systemic sclerosis) having defined reactivity to antigens other than mitochondrial antigens were also examined for AMA with both substrates; 19 of them resulted AMA negative. AMA diagnosis on mouse sperm substrate was found to be more sensitive than conventional rat kidney substrate. In addition, it has the advantage that it facilitates for the observer the visualization and reading of the fluorescent reaction on the mitochondria, due to the particular distribution of them on mouse sperms.

[Experience of a single center in liver transplantation in adults and children]

Orthotopic liver transplantation (THO) is the treatment of choice for a variety of liver diseases. The national experience before 1993 has been scarce. In November 1993 we started our experience in THO at Clínica Las Condes, as part of a multiorgan transplant program (liver, kidney, pancreas). Until January 1995 we have performed 14 THO in 13 recipients (one retransplantation), of which 5 were in pediatric cases. The recipients range of age fluctuated between 1 and 61 years. In two pediatric cases a liver allograft reduction was performed. Six recipients (46%) required treatment for acute cellular rejection. One recipient had an hepatic artery thrombosis and had to be retransplanted. There was no operative mortality up to 30 days in cases of primary liver transplants. The retransplanted adult recipient, and another pediatric recipient that died from a late recurrence of a hepatoblastoma, accounted for the mortality of this experience. After an average follow up of 10 months, the actual patient survival in 85%. Of the 11 surviving recipients, 9 are in excellent conditions with a very good quality of life. This experience shows that an active liver transplant program in our country can be successful in obtaining results comparable to those published by very experienced foreign transplant centers.

Transperitoneal transport of sodium during hypertonic peritoneal dialysis

The mechanisms of transperitoneal sodium transport during hypertonic peritoneal dialysis were evaluated by kinetic modelling. A total of six nested mathematical models were designed to elucidate the presence or absence of diffusive, non-lymphatic convective and lymphatic convective solute transport. Experimental results were obtained from 26 non-diabetic patients undergoing peritoneal dialysis. The model validation procedure demonstrated that only diffusive and non-lymphatic convective transport mechanisms were identifiable in the transperitoneal transport of sodium. Non-lymphatic convective sodium transport was the most important quantitative transport mechanism during the first 90 min of the dwell. Significant sodium sieving was demonstrated and explains the observation of hypernatremia in dialysis with hypertonic dialysis fluid.

Platelet autoantibodies in patients with chronic liver disease

The thrombocytopenia in chronic liver disease (CLD) has been attributed mainly to hypersplenism, although other factors such as reduced mean life span with increased platelet turnover have also been demonstrated. Immunological abnormalities have been described in the pathogenesis and progression of CLD. In this sense, many studies have reported elevated levels of platelet associated IgG (PAIgG) in patients with CLD, and it has been suggested that PAIgG could represent true antiplatelet antibody. In this study we used a glycoprotein (GP)-specific immunoassay (MACE) to determine whether PAIgG or circulating antiplatelet antibodies, reacted against the GPIIb/IIIa or GPIb/IX complexes, in patients with CLD. Thirty-six patients with CLD of diverse etiology were studied (20 female, mean age 53 years, range 38-75 years). 23 out of 36 patients (64%) had anti-GP antibodies in MACE. Particularly, 12 had anti-GPIb, 4 anti-GPIIb/IIIa, and 7 had both types of autoantibodies. The existence of these anti-GP antibodies was not related with the blood platelet count or etiology of CLD. These data show that in patients with CLD of diverse origin, there is a high prevalence of autoantibodies reacting specifically with platelet membrane GP, which constitutes the first evidence of the specific nature of platelet-bound IgG in CLD. These findings suggest that in patients with CLD, an immune mechanism may participate in inducing or aggravating the thrombocytopenia.

Kinetics of chloride transport across fish red blood cell membranes

The continuous flow tube method was used to investigate the kinetics of chloride transport, and its potential oxygenation-dependency, in red blood cells (RBCs) from four teleost fish species and man. A significant interspecific variation in Cl- transport kinetics was found. At 15 &deg;C, the rate constant k for unidirectional 36Cl- efflux was significantly lower in RBCs from eel and carp than in RBCs from rainbow trout and Atlantic cod. The values of k of cod RBCs at 15 &deg;C and of human RBCs at 37 &deg;C were not significantly different. The volume and surface area of the RBCs were evaluated and used to calculate the apparent membrane permeability to Cl- (PCl). The magnitude of PCl followed the sequence: eel&lt;carp&lt;trout&frac34;cod. PCl values in trout and cod at 15 &deg;C were similar to human values at 37 &deg;C. An extrapolation of human values to 15 &deg;C revealed that the Cl- shift at this temperature was considerable faster in all four teleosts than in man. This illustrates appropriate adaption of band-3-mediated anion transport to the different temperature regimes encountered by fish and mammals. The Cl- transport kinetics did not differ significantly between oxygenated and deoxygenated RBCs in any of the species examined. The apparent absence of any effect of a change in haemoglobin oxygen-saturation may be related to the presence of a flexible link which results in minimal interaction between the membrane domain (mediating Cl- transport) and the cytoplasmic domain (to which oxygenation-dependent haemoglobin binding occurs) of band 3. In carp, Cl- transport kinetics were not influenced by pH over the extracellular pH (pHe) range 7.6&shy;8.36, which spans the in vivo pHe range. The data are discussed in relation to the rate-limiting role of red blood cell HCO3-/Cl- exchange for CO2 excretion.

Validation of red cell sodium-lithium countertransport measurement--influence of different loading conditions

Increased sodium-lithium countertransport in erythrocytes from patients with long-standing type I (insulin-dependent) diabetes mellitus has been considered as an early marker of nephropathy. Since the activity and kinetics of the sodium-lithium countertransport may critically depend on loading conditions, this study was aimed at determining sodium-lithium countertransport activity, Michaelis constant Km and maximum velocity Vmax in erythrocytes loaded in two different Li+ solutions. Sodium-lithium countertransport activity was determined in erythrocytes in 8 healthy control subjects after loading with 150 mmol/l LiCl compared with those loaded with 150 mmol/l LiHCO3. Sodium-lithium countertransport activity was similar for both loading procedures, although the erythrocyte lithium content did significantly differ (mean +/- SEM, 7.0 +/- 0.5 for LiCl and 8.9 +/- 0.5 mmol/l of cells for 150 mmol/l LiHCO3). There were no significant changes in the Km and Vmax. Increase of osmolality in efflux media containing 200 and 250 mmol/l NaCl resulted in a negligible shrinking of the red blood cells, not exceeding 2.2%. The main advantage is the short loading time of 15 min for LiHCO3 compared with 3 hours for LiCl. Under these conditions saturating intracellular Li+ concentrations can be obtained much more rapidly than with LiCl loading, thereby minimising alterations of the cell membranes. LiHCO3 loading shortens the experimental time considerably and enables a greater number of samples to be screened from larger population cohorts.

An evaluation of twelve nested models of transperitoneal transport of urea: the one-compartment assumption is valid

Models of transperitoneal urea transport are generally based on the one-compartment assumption, i.e. that the plasma water urea concentration in the peritoneal capillary bed is equal to the plasma water urea concentration in the peripheral veins. The aim of this study was to investigate the mechanism(s) of transperitoneal urea transport and to test the one-compartment assumption for urea. A total of 12 nested models were formulated and validated on the basis of experimental results obtained from 23 non-diabetic patients undergoing peritoneal dialysis. The validation procedure demonstrated that transperitoneal transport of urea probably involves diffusion, non-lymphatic convection and lymphatic convection. It was furthermore demonstrated that the inclusion of lymphatic convection changes the mass transfer area coefficient considerably. Finally, no deviation from the one-compartment assumption was demonstrated by our results.

[Pre S1 antigen in different forms of hepatitis B virus infection]

Pre S1 antigen was measured using an ELISA technique in patients with different forms of hepatitis B virus infection. It was detected in 10 of 19 patients with acute hepatitis B (53%), 12 of 15 chronic hepatitis B virus carriers (80%), 9 of 11 patients with chronic hepatitis B (82%) and 3 of 4 patients with hepatoma and positive markers of hepatitis B virus infection. Pre S1 remained positive beyond 150 days in two patients with acute hepatitis that evolved to chronicity. Among subjects with chronic hepatitis B that received interferon, pre S1 antigen negativized only in the patient that had a complete response. Pre S1 detection is an index of hepatitis B virus replication and its persistence determines chronicity. Its negativization after antiviral therapy should have a predictive value.

Parameter estimation in six numerical models of transperitoneal transport of potassium in patients undergoing peritoneal dialysis

The mechanisms of transperitoneal potassium transport during peritoneal dialysis were evaluated by validation of different mathematical models. The models were designed to elucidate the presence or absence of diffusive, non-lymphatic convective and lymphatic convective solute transport. Experimental results were obtained from 26 non-diabetic patients undergoing peritoneal dialysis. The validation procedure demonstrated that models including both diffusive and non-lymphatic convective solute transport were superior to the other models. Lymphatic convective solute transport was not identifiable. Furthermore, it was demonstrated experimentally that the equilibrium distribution of potassium between plasma water and dialysate did not differ from a Donnan equilibrium, although the precondition of the Donnan equilibrium was not fulfilled, i.e. the volumes on each side of the membrane were not constant and dialysate was not an ultrafiltrate of plasma.

Carbon monoxide in chronic uraemia related to erythropoietin treatment and smoking habits

In 69 patients on chronic haemodialysis, blood sampled randomly during dialysis was analyzed for carboxyhaemoglobin (COHb). The median value was 1.40% (range 0.9-2.3) in non-smoking patients and (1.4-7.5) in smokers. In non-smokers treated with erythropoietin (EPO) correlation was found between COHb and the weekly EPO dose (r = 0.57, p = 0.007). In smoking patients not given EPO, the COHb correlated well with the number of cigarettes smoked (r = 0.84, p = 0.003). The COHb values did not correlate to the haemoglobin values. It is concluded that COHb levels in uraemic non-smokers are elevated because of increased endogenous CO production from the enhanced erythrocyte turnover. As even low COHb levels may negatively influence the oxygen status of the uraemic patient, the addition of exogenous CO from cigarette smoking should be avoided.

[Osteopenia in primary biliary cirrhosis. Study in 20 patients]

We studied 20 female patients, aged 51 +/- 13.6 years old, with the diagnosis of Primary Biliary Cirrhosis (PBC) to assess osteopenia, main involved sites and its relation to menopause, some parameters of mineral metabolism and the degree of histological liver involvement. The diagnosis of PBC was based in histological, clinical and laboratory features. Bone densitometry was measured with a dual-photon densitometer and compared with values of a normal female population from the laboratory. When compared to controls, studied patients had a significantly lower lumbar spine bone density and total bone mineral content and a non significantly lower density in femoral neck and total body. Serum calcium, phosphorus, magnesium, PTH and urinary calcium/creatinine ratio were within normal limits. Lumbar spine density was not significantly lower in patients with more severe liver histological involvement and in postmenopausal women. No correlation was found between the duration of postmenopausal period and the degree of osteopenia. It is concluded that patients with PBC have a clear lumbar spine osteopenia and a lower total mineral content and that these parameters worsen in a non significant fashion in subjects along with liver histological involvement and with the length of post menopausal period.

[Long term follow-up of patients with chronic hepatitis due to hepatitis C virus]

Thirty two patients (18 males whose ages ranged from 32 to 68 years old) with hepatitis C virus chronic hepatitis (positive anti-HCV by ELISA, confirmed by RIBA II) that were followed by the authors during 2 to 25 years, were retrospectively analyzed. Thirteen subjects had a history of blood transfusions, one had an accidental pinprick and other a sexual contact with a HCV positive individual; the transmission source was not identified in the resting 19 subjects. Only five individuals had an acute onset. The rest of the patients had few symptoms with moderate and fluctuating transaminase elevations. Liver biopsy at the onset showed a chronic hepatitis with moderate activity, even in 15 individuals with cirrhosis (47%). During follow up, six subjects deteriorated clinically, appearing liver failure and three of these died 4, 5 and 14 years after the disease appearance. No subject developed a hepatocarcinoma.

[Gallbladder polyps. 2d Consensus Workshop of the Chilean Hepatology Association]

During a workshop, hepatologists analyzed and gave recommendations about gallbladder polyps. They arrived to the following agreements: gallbladder polyps of less than 10 mm should be followed with ultrasonography at 3, 6 and 12 months if there is no enlargement. If there is enlargement, a cholecystectomy should be performed. Polyps larger than 10 mm should be subjected to cholecystectomy.

The permeability of the human red cell membrane to steroid sex hormones

The release rates of the 3H-labeled steroid sex hormones estrone, estradiol, estriol, progesterone, and testosterone from the human red blood cell and resealed red cell ghosts were studied at 38 degrees C and pH 7.2 by means of the rapid continuous flow tube method which has a time resolution of a few milliseconds. Further, the equilibria between unbound hormone and hormone bound to red cells, resealed red cell ghosts and albumin were studied by partitioning analysis of trace amounts of labeled hormones. The half-times for release from erythrocytes under physiological conditions ranged from 4 ms (testosterone) to 150 ms (estriol). The release from ghosts was significantly faster than from cells preincubated with hormones at unphysiological high concentrations. Affinities of hormone binding to cells and hormone indicate that as much as 15-35% of the total hormone content in whole blood is confined to red cells. The ratio between bound and free hormone in the cell ranged from 5 to 10, and the ratio between cytoplasma-bound and membrane-bound hormone ranged between 3 and 9. The results are compatible with a model of fast transition of hormone through the red cell membrane and intracellular binding of hormone. We suggest that red cells function as carriers of sex hormones in the bloodstream in a manner similar to that of albumin, and that red cells may be responsible for 5-15% of sex hormone delivery to target tissues.

[A new substrate for the detection of antimitochondrial antibodies in human serum]

This work describes a new method to detect antimitochondrial antibodies using indirect immunofluorescence on mouse sperm as substrate. As controls conventional substrates and mitochondrial protein immunoblots were used. An intense fluorescent reaction was visualized in the mitochondrial sheet of mouse sperms allowing a straightforward diagnosis of positive sera. Sera coming from 10 patients with progressive systemic sclerosis, 12 patients with systemic lupus erythematosus and 17 patients with primary biliary cirrhosis were tested with this method, confirming results obtained with conventional tests that use indirect immunofluorescence and rat frozen kidney slices as substrate. The new method is simpler, more accurate and has a lower margin of error.

Chloride and bicarbonate transport in chick embryonic red blood cells

1. Unidirectional efflux of 36Cl- and H14CO3- from erythrocytes of 4- to 16-day-old chick embryos was measured under steady-state conditions at 37 degrees C and pH 7.7. The efflux rates were high, > 3 s-1, and were, therefore, measured by means of the continuous flow tube method. 2. At day 4 of development the range of permeability coefficients for bicarbonate and chloride (PHCO3 and PCl was 1-30 x 10(-4) cm s-1, with average values of respectively 10 x 10(-4) and 8 x 10(-4) cm s-1. However, the results can be divided into two groups, one with PHCO3 and PCl above 12 x 10(-4) cm s-1, and one with values below 5 x 10(-4) cm s-1. The same range of values was also obtained for day 6 erythrocytes, but the overlap is more conspicuous. At day 16, PHCO3 and PCl were respectively 9 x 10(-4) and 6 x 10(-4) cm s-1 (37 degrees C, pH 7.7). In adult chicken red blood cells PHCO3 and PCl were respectively 7 x 10(-4) and 4 x 10(-4) cm s-1, and in human red blood cells the respective values were 5.6 x 10(-4) and 4 x 10(-4) cm s-1. 3. Chloride self-exchange, measured at 0 degrees C, was almost completely inhibited by addition of 1 mM 4,4'-diisothiocyanostilbene-2,2'-disulphonate (DIDS) at both days 6 and 16 of embryonic development, supporting the finding that the embryonic chick erythrocytes also have a transmembrane anion exchanger similar to that of other red cells.(ABSTRACT TRUNCATED AT 250 WORDS)

[Hepatitis B and C virus infections in children with congenital coagulation disorders]

The prevalence of hepatitis B and C virus infections, transmitted by blood transfusions, was studied in 79 children with congenital coagulation disorders. Twenty nine percent had evidences of hepatitis B virus infection and 52% evidences of hepatitis C virus infection. Older children and those with the higher number of transfusions had the highest rates of infections. It is concluded that children with congenital coagulation disorders constitute a high risk group for hepatitis B and C virus infections.

[Hepatic angiosarcoma: report of 4 cases]

Hepatic angiosarcoma is an infrequent vascular liver tumor of high malignancy. Four patients (two males) are presented, in whom a histopathological study was performed. All patients died and in three a necropsy was executed.

[Correlation between serum globulin levels and hepatitis C virus antibody]

BACKGROUND

some studies have suggested that the elevation of serum globulins in patients with chronic autoimmune hepatitis, paraproteinemias and rheumatoid arthritis could affect the determination of false positive hepatitis C virus antibodies (anti-HCV).

AIM

to study the relationship between positive anti-HCV and serum levels of globulins in patients with liver disease.

PATIENTS AND METHODS

one hundred thirty one patients with liver disease, 49 alcoholic, 38 cryptogenetic, 17 autoimmune and 27 with other causes, were studies prospectively measuring simultaneously anti-HCV and serum levels of total, gamma and immuno-globulins (IgA, IgG and IgM). These levels were compared between anti-HCV positive and negative groups and correlated with the ratio between serum optical density/cutoff optical density of the anti HCV assay.

RESULTS

Twenty eight patients (21.3%) were anti-HCV positive, no differences in serum globulins between these patients and anti-HCV negative patients and no correlations between serum globulins and anti-HCV optical densities were observed.

CONCLUSIONS

the hypergamma-globulinemia observed in these patients with liver diseases would not be responsible for positive hepatitis C virus antibodies.

[Hepatitis B virus vaccine: early and late response in Chileans with high risk of infection]

BACKGROUND

Hepatitis B vaccine has demonstrated to be very effective and safe preventing hepatitis B virus infection. Long term protection induced by hepatitis B vaccination depends on the initial immune response and the declining rate of anti-HBs titers. AIM. To investigate early and late response to hepatitis B vaccine in a sample of high risk Chilean population.

MATERIAL AND METHODS

Thirty one subjects (20 relatives of hepatitis B chronic carriers, 10 health service workers and one HIV seropositive) were vaccinated with a plasma derivated hepatitis B vaccine. Early and late response were estimated by anti-HBs titers.

RESULTS

Twenty eight subjects (90%) produced protective titers of anti-HBs after 2 months from the third dose of vaccine (early response), and they remained at these levels in 75% of vaccinated individuals after three years (late response). All the subjects without protective titers after the three year follow up had produced anti-HBs levels lower than 300 UI at the early response. Hepatitis B vaccination was not associated with significant side effects.

CONCLUSIONS

This experience confirms that hepatitis B vaccine is safe and effective inducing immunity in high risk subjects. Our data suggest that the early response to hepatitis B vaccine is able to identify those subjects requiring closer surveillance for boosters.

[Bacteriuria in patients with primary biliary cirrhosis]

BACKGROUND

Controversies exist about the association between significant bacteriuria and primary biliary cirrhosis. There is evidence suggesting that infections by Gram negative bacteria may be implicated in the pathogenesis of this liver disease.

AIM

To compare the incidence of bacteriuria in patients with primary biliary cirrhosis and those with autoimmune chronic hepatitis.

PATIENTS AND METHODS

Twenty women with primary biliary cirrhosis and twenty three female patients with autoimmune chronic hepatitis were prospectively studied by routine bacteriological cultures of midstream urine specimens. Samples were obtained at three months intervals or when patients complained of symptoms suggesting urinary tract infection. Significant bacteriuria was defined as the growth of > 10(5) organisms/ml in pure culture.

RESULTS

During 8 +/- 1 months of follow up. 60 urine samples from patients with primary biliary cirrhosis and 73 from autoimmune hepatitis cases were tested. Twenty one samples of patients with primary biliary cirrhosis (35%) were positive for significant bacteriuria compared with 7 from women with autoimmune hepatitis (9%); p < 0.01. In the follow up, ten patients with primary biliary cirrhosis (50%) and six with autoimmune hepatitis (26%) developed at least one episode of significant bacteriuria.

CONCLUSION

These results suggest that female patients with primary biliary cirrhosis are in higher risk of significant bacteriuria than women with autoimmune hepatitis. Prospective studies evaluating the effects of long-term antibiotic therapy on cholestasis parameters in primary biliary cirrhosis are deserved.

Kinetics of residual chloride transport in human red blood cells after maximum covalent 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid binding

Irreversible inhibition, 99.8% of control values for chloride transport in human red blood cells, was obtained by well-established methods of maximum covalent binding of 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS). The kinetics of the residual chloride transport (0.2%, 106 pmol.cm-2 x s-1) at 38 degrees C, pH 7.2) was studied by means of 36Cl- efflux. The outside apparent affinity, expressed by Ko1/2,c, was 34 mM, as determined by substituting external KCl by sucrose. The residual flux was reversibly inhibited by a reexposure to DIDS, and by 4,4'-dinitrostilbene-2,2'-disulfonate (DNDS), phloretin, salicylate, and alpha-bromo-4-hydroxy-3,5-dinitroacetophenone (Killer III) (Borders, C. L., Jr., D. M. Perez, M. W. Lafferty, A. J. Kondow, J. Brahm, M. B. Fenderson, G. L. Breisford, and V. B. Pett. 1989. Bioorganic Chemistry. 17:96-107), to approximately 0.001% of control cells, which is a flux as low as in lipid bilayers. The reversible DIDS inhibition of the residual chloride flux depended on the extracellular chloride concentration, but was not purely competitive. The half-inhibition concentrations at [Cl(o)] = 150 mM in control cells (Ki,o) and covalently DIDS-treated cells (Ki,c) were: DIDS, Ki,c = 73 nM; DNDS, Ki,o = 6.3 microM, Ki,c = 22 microM; phloretin, Ki,o = 19 microM, Ki,c = 17 microM; salicylate, Ki,o = 4 mM, Ki,c = 8 mM; Killer III, Ki,o = 10 microM, Ki,c = 10 microM.

[Post sinusoidal obstruction of the hepatic venous flow associated with antiphospholipid syndrome in 3 cases]

Three cases of post-sinusoidal hepatic blood flow obstruction as the main feature of antiphospholipid syndrome are reported. Clinically, these patients developed jaundice, malaise, ascites and hepatomegaly. Ultrasonography-Doppler and hepatic venography showed small hepatic vein disease in two and partial occlusion in the suprahepatic segment of inferior vena cava in the remaining patient. In all, anticardiolipin antibodies were positive and activated partial thromboplastin time was prolonged. This experience emphasizes that in patients with post sinusoidal portal hypertension, a systematic search for antiphospholipid syndrome must be carried out.