Chronic intestinal ischaemia: measurement of the total splanchnic blood flow.

A redundant collateral network between the intestinal arteries is present at all times. In case of ischaemia in the gastrointestinal tract, the collateral blood supply can develop further, thus accommodating the demand for oxygen even in the presence of significant stenosis or occlusion of the intestinal arteries without clinical symptoms of intestinal ischaemia. Symptoms of ischemia develop when the genuine and collateral blood supply no longer can accommodate the need for oxygen. Atherosclerosis is the most common cause of obliteration in the intestinal arteries. In chronic intestinal ischaemia (CII), the fasting splanchnic blood flow (SBF) is sufficient, but the postprandial increase in SBF is inadequate and abdominal pain will therefore develop in relation to food intake causing the patient to eat smaller meals at larger intervals with a resulting weight loss. Traditionally, the CII-diagnosis has exclusively been based upon morphology (angiography) of the intestinal arteries; however, substantial discrepancies between CII-symptoms and the presence of atherosclerosis/stenosis in the intestinal arteries have been described repeatedly in the literature impeding the diagnosis of CII. This PhD thesis explores a method to determine the total SBF and its potential use as a diagnostic tool in patients suspected to suffer from CII. The SBF can be measured using a continuous infusion of a tracer and catheterisation of a hepatic vein and an artery. By measuring the SBF before and after a standard meal it is possible to assess the ability or inability to enhance the SBF and thereby diagnosing CII. In Study I, measurement of SBF was tested against angiography in a group of patients suspected to suffer from CII due to pain and weight loss. A very good agreement between the postprandial increase in SBF and angiography was found. The method was validated against a well-established method independent of the hepatic extraction of tracer using pAH in a porcine model (study II). An excellent agreement was found between the two methods for the measurement of SBF. In the same set-up metabolism and recirculation in the intestines of the 99mTechnetium labelled tracer was rejected based on the consistency between the portal and arterial contents of tracer. Based on this study we concluded that an arterial blood sample can be used instead of a portal blood sample, making the method applicable to patients. In study III, 20 healthy volunteers and 29 patients with weight loss and abdominal pain but normal morphology of the intestinal arteries were investigated. A reference value for the meal induced SBF-increase and the relation to bodyweight was established designating that bodyweight should be taken into account when diagnosing CII based on measurement of SBF. The clinical method for measuring the SBF based on hepatic 99mTc-MBF extraction is a robust method. It allows determination of the postprandial increase in SBF providing knowledge about the circulatory physiology in intestines in patients with weight loss and abdominal pain with or without intestinal arterial stenosis. Future studies within this field could include measurement of the SBF before and after revascularisation in order to quantify the effect of revascularisation or investigate whether arterial blood sampling could be avoided or the amount of blood samples (and thus the time spend) could be reduced. The three studies were presented at eleven national and international congresses and Helle Damgaard Zacho has been awarded three prizes for the presentations.

Systemic and local release of inflammatory cytokines regulates hepatobiliary excretion of 99mTc-mebrofenin.

OBJECTIVES: Imaging agents capable of providing cell compartment-specific information will facilitate studies of pathophysiological mechanisms, natural history of diseases, and therapeutic development. To demonstrate the effects of liver injury on the disposal of the organic anion mebrofenin, we performed animal studies. METHODS: Acute liver injury was induced in Fischer 344 rats with 0.25-1 ml/kg single doses of carbon tetrachloride followed by studies of animals over 4 weeks. The liver injury was analyzed by blood tests and histological grading. Additional rats were treated with lipopolysaccharide, interleukin-6 or tumor necrosis factor-alpha to activate inflammatory events. Hepatic clearance of Tc-mebrofenin was studied with dynamic imaging and fractional retention after 60 min of peak hepatic mebrofenin activity was determined. RESULTS: In healthy rats, only 24+/-2% of peak mebrofenin activity was retained in the liver after 60 min. By contrast, 24 h after carbon tetrachloride, virtually all mebrofenin activity was retained in the liver (P<0.001). Three weeks were required for mebrofenin excretion to become normal after carbon tetrachloride administration. In this situation, we found that Kupffer cell activity was increased. In addition, the abnormality in mebrofenin excretion was reproduced by lipopolysaccharide, which activates Kupffer cells. Moreover, mebrofenin excretion was highly sensitive to interleukin-6 and/or tumor necrosis factor-alpha, which help mediate the Kupffer cell response. CONCLUSION: Hepatobiliary excretion of mebrofenin was affected rapidly and over an extended period by inflammatory cytokines released after liver injury. The remarkable sensitivity of mebrofenin excretion to cytokines suggests that Tc-mebrofenin imaging will be helpful for assessing cytokine-mediated liver inflammation.

(99m)Tc-HEPIDA hepatic clearance as a diagnostic tool: usefulness of a single sample plasma and hepatic clearance of (99m)Tc-HEPIDA for assessment of hepatic parenchyma performance.

BACKGROUND: A simplified method of (99m)Tc-HEPIDA clearance determination, both plasma and hepatic, depends upon measuring the radiopharmaceutical concentration in plasma of a blood sample taken once in the time range from 68-83 min after injection of compound, and measurement of activity voided (excreted) with urine about five minutes after blood sampling. The aim of the present study was to analyze the clinical usefulness of both clearances, as determined by the simplified method in view of the diagnostic usefulness of both clearances (particularly of hepatic clearance) as determined by the respective multisampling method. MATERIAL AND METHODS: For the analysis, archived data of studies in 134 individuals (48 healthy individuals and 86 patients with chronic liver parenchyma damage) were used, in which plasma clearance (Cl(Pl)) and hepatic clearance (Cl(Hp)) (99m)Tc -HEPIDA were determined by the standard multisample method--the values of such determined clearances constituted clearance referential values for further comparative analyses. The clearances Cl(Pl) and Cl(Hp) were determined by the simplified method separately for three blood sampling times of: 60, 75 and 90 min, using the same archived data for calculation of corresponding concentrations of (99m)Tc-HEPIDA in plasma. For urinary clearances--which were necessary for calculation of Cl(Hp)--archived data were utilized on activity contained in voided urine (at about 95 min.). The clinical reference system used here was the semi-quantitative assessment of liver function, performed on the basis of commonly used basic biochemical indices (AST, ALT, GGTP, bilirubin, albumin and gammaglobulin in serum, proteinogram and prothrombin index). For each test there were 4 categories of results (sub-ranges) selected, which were ranked from 0 to 3. For each patient the ranks for the results of each test were summed, giving a total sum (called SP). These latter sums of ranks served as a reference system, characterizing liver condition (performance) in each individual. RESULTS: Clearance, Cl(Pl) and Cl(Hp), values, obtained by a simplified method, were correlated with respective values determined by the multisampling method, and with ranks (SP) representing classification of degree of hepatic parenchyma damage--SP. On the basis of the attribute independence Chi(2) test, the coherence of clearances (simplified determination) with SP was assessed. Also, analysis of variance of SP-values and clearance was performed using Spearman's theory for testing the correlation of non-continuous variables. By factorial analysis a factor responsible for changes in individual quantities (results of biochemical tests and (99m)Tc-HEPIDA clearances) was computed. Its loading was determined for each individual quantity. During analysis for each moment of blood sampling tight correlations of clearance values, obtained by the simplified method, were determined with referential values. The closest correlation was obtained for blood sampling at 75 min. It was found that there are negative correlations between values of hepatic and plasmatic clearances and SP. The values of r obtained for Cl(Hp) are close to those obtained for analogical correlations by multisampling methods. However, the values of correlation coefficient obtained for Cl(Pl) by single sample method are greater than those for Cl(Pl) determined by multisampling method. CONCLUSIONS: Factor loading, known as "liver incapacity", is greater for Cl(Hp) determined by single sample method, but lower than comparable hepatic clearance loading determined by the multi-sample procedure. Values of incapacity factor for Cl(Pl) are lower than for Cl(Hp), but the lowest value was obtained for Cl(Pl) determined by the multisampling method. Obtained values Chi(2), r and loading of incapacity factor speak in favour of the correlations between the degree of hepatic parenchyma performance and the values of clearances determined by the simplified method. However, this correlation is closer for Cl(Hp) than for Cl(Pl). In view of such a distinct correlation, there is good justification for the implementation of the simplified method for the determination of hepatic clearances used in diagnostic analysis of hepatic performance.

99mTc-HEPIDA hepatic clearance as a diagnostic tool: usefulness of plasma and hepatic clearance for assessment of hepatic parenchyma performance.

Plasma clearance of (99m)Tc-HEPIDA (Cl(Pl)) has been used for two decades for assessment of liver function in patients with diseases of this organ. A specific determination of (99m)Tc-HEPIDA liver clearance (Cl(Hp)) has been developed that provides more direct possibility to evaluate performance of liver parenchyma. Both tests have been studied in healthy volunteers of varying age (48 individuals) and in 83 patients with varying degree of liver damage. The liver damage has been evaluated on the basis of 5 biochemical tests (AspAT, ALAT, GGTP, bilirubine serum concentration, proteinogram) and a score system used for total impairment, which was calculated for each patient. Normal range of Cl(Pl) and Cl(Hp) was determined from a study on healthy individuals (volunteers). The results seem independent of age, but show sex differences. The following values (mean +/- SD) of Cl(Hp) were found in males and females of: (181 +/- 31) ml//min/1.73 m(2) and (158 +/- 22) ml/min/1.73m(2), and of Cl(Pl) were (224 +/- 33) ml/min/1.73 m(2) and (202 +/- 25) ml/min/1.73 m(2) respectively. Accepted lower boundaries of both quantities (mean -2SD) are 115 ml/min/1.73 m(2) and 150 ml/min/1.73 m(2) correspondingly. Negative correlation of individual values of both clearances in all patients with individual score of liver damage were highly significant and correlation coefficients obtained were higher for Cl(Hp) (r = -0.63) than those for Cl(Pl) (r= -0.56). Factorial analysis was performed with the intention of seeing which of the studied factors had the highest factor loading for parenchyma performance that was assumed as the common factor responsible for correlations. The highest value was obtained for hepatic clearance (Cl(Hp)) of (99m)Tc-HEPIDA. In conclusion this quantity seems highly promising as a clinically useful test for assessment of liver performance, both in screening for liver damage and for monitoring of organ conditions during therapy and follow-up of patients.

Evaluation of plasma time-activity curves of technetium-99m-mebrofenin for measurement of hepatic function in dogs.

In this study, plasma time-activity curves of 99mTc-mebrofenin were used to quantify hepatic function in dogs before and after induction of hepatic damage using a hepatotoxic agent. Nine dogs were determined to be healthy on the basis of physical examination, laboratory data and hepatic imaging. Plasma samples were collected 1, 3, 5, 7, 9, 15, 20, 30, 40, 50, and 60 minutes following a peripheral venous injection of 111-222 MBq (3-6 mCi) of 99mTc-mebrofenin. The area under the plasma time-activity curve (AUC) was calculated using two different methods and compared to direct measurement of the hepatic extraction efficiency. First pass hepatic extraction efficiency of 99mTc-mebrofenin was calculated from differential equation analysis of a two-compartment model following mesenteric venous injection of the radiopharmaceutical. In 7 of the original 9 dogs and 2 additional healthy dogs, plasma clearance and hepatic extraction efficiency determination were repeated following induction of hepatic injury by thiacetarsamide (3 mg/kg IV twice daily for 1 day). In one additional dog, hepatic injury was induced using carbon tetrachloride (0.3 ml/kg IP). Plasma time-activity curves of 99mTc-mebrofenin had kinetics of a two compartment model. Area under the curve was highly correlated with hepatic extraction efficiency. The AUC integrated from 1-60 minutes (AUC60) had the best correlation with hepatic extraction efficiency (r2 = 0.978, p < 0.001). A formula for calculation of hepatic extraction efficiency was derived using linear regression analysis: hepatic extraction efficiency = 105.583 - 3.099 x 10(5) x AUC60. Plasma clearance of a peripheral venous injection of 99mTc-mebrofenin is a simple, non-invasive, convenient method to quantify hepatic function which can be performed without a gamma camera.

Blood clearance of 99mTc-trimethyl-Br-IDA discriminates between different degrees of severe liver ischaemia--reperfusion injury in the rat.

The kinetics of 99mTc-Trimethyl-Br-IDA blood clearance was analysed in the rat 24 h after warm ischaemia and reperfusion of the liver. There were changes in the elimination of 99mTc-Trimethyl-Br-IDA depending on the length of the ischaemic period and the dose given. Statistically significant differences were found between the various periods of ischaemia when higher doses of the radionuclide were utilised. At lower doses, the clearance was not capable to discriminate between control rats and rats submitted to 45 min of ischaemia, but it did discriminate more severe degrees of ischaemic liver injury. Instead, galactose elimination capacity discriminated between ischaemic and control rats, but not between 45 and 90 min or between 90 and 120 min of ischaemia. Alanine aminotransferase was able to discriminate between control and ischaemic rats and between 45 and 90 min of ischaemia, but not between 90 and 120 min of ischaemia. The response of 99mTc-Trimethyl-Br-IDA clearance under extreme conditions of ischaemia and reperfusion is consistent and opens a possible window for the application of this test in the quantification of liver function in severely damaged livers and in decision making and prognosis in liver disease.

Blood cell to plasma gradients of amino acids in arterial and venous blood in fed and fasted rats.

Measurement of amino acid concentrations in blood cells and plasma, and the calculated blood cell to plasma gradients (C/P) from both afferent and efferent vessels to tissues, allowed evaluation of the effect of several tissues (splanchnic bed, skeletal muscle and kidney) on blood amino acid distribution in fed and starved rats. Combined effects of tissues and erythrocyte transport capabilities determined specific C/P values for each amino acid. For amino acids related to the L-system, the high capacity of this erythrocyte transport many buffer some C/P changes as an effect of tissue metabolism. For less permeable amino acids (like Asp and Glu) plasma changes were mainly responsible for changes in C/P values, whereas for other amino acids (such as basic amino acids) blood cells became the main determinants of C/P changes, mainly in starvation. In general, the role of erythrocytes in amino acid transport was enhanced in starvation.

Experimental toxic liver damage and hepatic plasma clearance of 99mTc-mebrofenin (iminodiacetate derivative). II. Recovery from the acute, CCl4-induced liver damage.

Liver parenchyma damage was induced in rabbits by the administration of carbon tetrachloride. The animals were serially sacrificed 3, 10, 17 and 31 days post intoxication and examined morphometrically for the extent of necrosis, steatosis and balloon degeneration of hepatocytes. Biochemical indices of the liver damage were studied as well as hepatic clearance of blood plasma from Tc-99m complex of an IDA derivative Tc99m complex (99mTc-mebrofenin--99mTc-MBF) and its uptake and liver transfer characterizing parameters. It was found that toxic effects of CCl4 were conspicuous up to 10 days after administration of carbon tetrachloride. In that period elevated activity of AspAT, ALAT, GGTP and elevated cholesterol and triglycerides were found in the plasma. As in the first paper of this series of works there has been a highly significant statistical association between the Tc-MBF plasma clearance, the uptake and liver transfer of the compound and parenchyma damage in the organ.

Quantitation of the hepatobiliary dynamics in clinically normal dogs by use of 99mTc-iminodiacetate excretory scintigraphy.

The hepatobiliary dynamics of a 99mTc-labeled derivative of iminodiacetate were investigated in 29 healthy dogs. A 2-compartment model proved to be adequate to describe the hepatic time-activity curve. Model-derived variables for the hepatic accumulation and the biliary excretion and transport were used as a reference for evaluation of a number of commonly used measurements directly derived from hepatic and biliary time-activity curves (graphic variables). The difference between t50(ex) and t95(ex), representing the moments when 50 and 95%, respectively, of the maximal count rate during the hepatic excretory phase were measured, proved to be an adequate graphic variable to quantitate biliary excretion. The use of other graphic variables to quantitate hepatobiliary functions seemed unjustified.

Hepatic handling of a synthetic gamma-labeled bile acid (75SeHCAT).

75Se-homocholic acid-taurine (75SeHCAT) is the first available gamma-labeled bile acid, and should therefore be handled more efficiently and specifically by the liver than previous hepatoscintigraphic agents. We have measured serum and hepatic kinetics for 75SeHCAT, and compared them with those for the conventional hepatobiliary scintigraphic agent 99mTc-hepatoiminodiacetic acid, and with serum kinetics for the corresponding natural bile acid, [14C]cholic acid-taurine. We used a dynamic scintigraphic technique and serial blood sampling in 8 subjects. Initial hepatic uptake rate was identical to initial serum disappearance rate (14% dose/min) for 75SeHCAT, but significantly lower for 99mTc-hepatoiminodiacetic acid (6% vs. 14% dose/min, p less than 0.001). Hepatic transit time was shorter for 75SeHCAT (13 min vs. 22 min, p less than 0.02), net hepatic excretory rate was more rapid (1.4% vs. 0.8% dose/min, p less than 0.001), and urinary excretion was lower (1.0% vs. 9.0% dose, p less than 0.001). Initial and late-plasma disappearance rates were significantly lower for 75SeHCAT (14.3% and 1.5% dose/min) than for [14C]cholic acid-taurine (21.3% and 2.8% dose/min, respectively), and plasma clearance was also lower (275 vs. 670 ml/min). In vitro, 75SeHCAT was bound to serum proteins more completely than [14C]cholic acid-taurine (90.4% vs. 86.5%, p less than 0.005). We conclude that 75SeHCAT provides a hepatoscintigraphic agent that is handled more efficiently and specifically by the liver than the conventionally used agent 99mTc-hepatoiminodiacetic acid. It is not cleared from the serum as rapidly as [14C]cholic acid-taurine, probably due to its stronger protein binding. The clinical value of 75SeHCAT in assessing liver disease should be investigated.

Pharmacokinetic studies of DISIDA disposition. II. Clinical studies.

The whole blood pharmacokinetics of intravenously administered 99mTc-disofenin (DISIDA) has been studied in normal subjects and patients with documented liver disease. The apparent overall whole blood disposition rates of radioactivity were calculated from serial blood data, in order to evaluate liver clearance of DISIDA. The measurements obtained clearly discriminated 9 normal subjects from 7 patients with severe liver disease causing jaundice--1233 mls/min vs 384 mls/min (P less than 0.002). Nine subjects with liver disease of insufficient severity to cause jaundice also had clearly abnormal DISIDA disposition--642 ml/min (P less than 0.05 for difference to controls). The time activity curves from all subjects showed biexponential elimination of blood activity, with a rapid (T1/2 = 3.8 min) and a slow disposition phase (T1/2 = 75 min) in normals. These curves were fitted by computer to the timed rate of hepatic uptake, simultaneously obtained by gamma imaging over the liver. It was not possible to satisfactorily fit these using a model which assumed distribution of a single compound within two body compartments. However, another which assumed the administration of two radioactive agents satisfactorily fitted the two types of data. This conclusion is consistent with our animal experiments which indicate the existence of two compounds in injected DISIDA with contrasting high and low hepatic extraction efficiency (Fraser et al. 1988). A pharmacokinetic approach to DISIDA disposition can yield quantitative information which discriminates different degrees of liver dysfunction, but the mechanisms involved are more complicated than previously thought, so that further study should permit very precise quantification.

Pharmacokinetic studies of DISIDA disposition. I. Animal studies.

The whole blood pharmacokinetics of intravenously administered 99mTc-disofenin (DISIDA) have been studied in dogs. Serial blood sampling permitted calculation of whole blood disposition rates, which principally represent liver clearance. There were striking differences in these rates between 6 normals and 7 animals in whom liver damage was induced by chronic bile duct ligation (256 vs 58 ml/min, P less than 0.001). Blood levels of radioactivity fell in a biexponential fashion characterized by rapid and slow disposition phases, whose half times were 2.4 and 58 min in normal animals. On 3 occasions, plasma was obtained from 1 animal by exsanguination 35 min after the administration of DISIDA and rapidly transfused into a 2nd animal. The whole blood pharmacokinetics of the second (recipient) animal showed a predominance of the slow disposition phase and a small rapid phase. The hepatic extraction ratio of blood radioactivity was measured in 3 dogs and was high (75%-90%) early after injection of DISIDA, but fell rapidly to remain around 10%. These experiments suggest the presence of two different species in the radiopharmaceutical studied, each being removed from the blood stream by the liver, but at different rates. The contribution of renal clearance to overall whole blood pharmacokinetics was negligible, since three nephrectomized dogs displayed similar pharmacokinetics to normals. Whole blood DISIDA pharmacokinetics are more complex than previously thought but appear to be capable of providing an accurate measure of liver function.

Long-term clinical investigation of the hepatobiliary agents: 99mTc-HIDA and 99mTc-p-butyl-IDA.

The organ distribution data for the two hepatobiliary agents HIDA and p-butyl-IDA in mice showed substantial differences in the extent and rate of hepatobiliary clearance of radioactivity. 99mTc-HIDA and 99mTc-p-butyl-IDA were used in computer assisted serial hepatobiliary scintigraphy. In normal subjects, the data of dynamic studies showed that the kidneys were no longer seen after 2.5 min with p-butyl-IDA. Liver radioactivity decreased significantly after 10 min with HIDA compared to 35 min with p-butyl-IDA. The gall bladder was always visualized at the 10-12th min and the 25-30th min with HIDA and p-butyl-IDA respectively. 99mTc-HIDA provided superior hepatic duct images.

Imino acid and related alicyclic amine levels in biological fluids.

Imino acid and related alicyclic amine concentrations in blood and urine of mammals including humans were concurrently determined by a selected ion monitoring technique. Nanomole levels of proline and pipecolic acid, and pyrrolidine and piperidine as well, were found in human urine. Proline levels but not pipecolic acid levels were higher in blood of humans than in urine. Pyrrolidine and piperidine levels in blood of humans were picomole levels and much lower than those in urine. Similar tendencies were also recognized when these 4 compounds were analyzed using animal blood and urine, although the levels were generally higher in animals than in humans. Significantly high concentrations of the imino acids and the amines were found also in animal semen.

[Analysis of 99mTc-HIDA kinetics using an adaptive model]. / Analiz kinetiki 99mTc-HIDA s pomoshch'iu adaptivnoi modeli.

The paper is concerned with the results of assaying hepatocyte function on the basis of an adaptive pharmacokinetic model worked out by the authors. Hepatoscintigraphy with 99mTc-HIDA was used in 3 phases: the vascular phase of RP transport (the 1st min of investigation, scintigrams with a 2 s interval), the parenchymatous phase (with a 20 s interval in subsequent 10 min), the biliary phase (with a 3 min interval). The hepatocytic phase of 99mTc-HIDA transport was evaluated on the basis of the adaptive 5-compartmental model calculating the value of transport constants. In terms of differential diagnosis, the intercompartmental constants K1,2 (blood-liver) and K2,1 (liver-blood) turned out to be the most informative. Thus the assaying of hepatocyte transport function using the proposed adaptive model helps to define the degree of liver involvement in a pathological process, to choose the therapeutic tactics and method, to evaluate its efficacy and to predict possible complications.

High-performance liquid chromatographic analysis of free hydroxyproline and proline in blood plasma and of free and peptide-bound hydroxyproline in urine.

A rapid, accurate and sensitive method for the determination of free hydroxyproline and proline in plasma and of total hydroxyproline in urine has been developed. Free imino acids and internal standard are extracted from plasma by trichloroacetic acid precipitation of protein and they are selectively derivatized with 4-chloro-7-nitrobenzofurazan, after reaction of the acid extract with o-phthalaldehyde. The highly fluorescent adducts of imino acids are separated on a Spherisorb ODS 2 reversed-phase column using acetonitrile-0.1 M sodium phosphate buffer, pH 7.2 (9:91, v/v) as mobile phase, followed by fluorometric detection. Total hydroxyproline determination in urine hydrolysates is carried out by reaction of the imino acid with 4-chloro-7-nitrobenzofurazan after clean-up on a Sep-Pak C18 cartridge of the o-phthalaldehyde-treated sample, high-performance liquid chromatographic separation and fluorometric quantitation of the derivative.

Simplified procedure for specific determination of imino acids in human blood plasma by high-performance liquid chromatography.

After deproteinization with 70% aqueous ethanol and evaporation to dryness, a plasma sample was subjected to the formol reaction. Then Dns derivatization of imino acids was carried out for 20 min at 37 degrees C. An aliquot of the resulting solution was subjected to reversed-phase chromatography using continuous gradient elution with acetonitrile-50 mM acetate buffer (pH 4.0) as solvent system. This method is selective for imino acids. Hydroxyproline and proline levels could be determined using 30 microliter of plasma.

Plasma transport of 99mTc-p-butyl-IDA.

Plasma transport of 99mTc-p-butyl-IDA was measured by four in vitro methods: trichloroacetic acid precipitation, electrophoresis, HPLC, and Scatchard binding isotherm. The data are in accord with protein transport, the main carrier being albumin with two categories of sites. This work suggests that after IV injection of 99mTc-p-butyl-IDA in humans plasma protein binding is one of the limiting factors for the hepatic deposition of the radiopharmaceutical.

[Hepatic clearance of 99mTc-p-butyl HIDA in liver diseases. Correlations with routine hematochemical parameters of liver function]. / La clearance epatica del 99mTc-p-butil IDA nelle malattie del fegato. Correlazioni con i parametri ematochimici routinari di funzionalità epatica.

The aim of the present investigation was to study the clearance of 99mTc-p-butyl IDA in some acute and chronic liver diseases, it being considered that the typical parameters obtained with this method are as indicative as any of the others put forward for the study of liver function using radioisotopes. 46 subjects were examined: 6 with acute hepatitis, 10 with chronic hepatitis, 18 with liver cirrhosis and 12 with dyspepsia but otherwise normal haematochemical tests. Two basic 99mTc-p-butyl IDA clearance parameters, Tu (semi-take up time) and Te (semi-excretion time), were determined plotting the data obtained using a Gamma-Camera on semi-logarithmic paper. Mean Tu values were as follows: 5'06'' +/- 1'24'' in dyspeptics, 12'30'' +/- 6'31'' in subjects with acute hepatitis, 6'30'' +/- 1'45'' in subjects with chronic hepatitis and 13'30'' +/- 4'30'' in subjects with cirrhosis. The values were: 34'30'' +/- 4'30'' in dyspeptics, 49'54'' +/- 2'36'' in subjects with acute hepatitis, 42'24'' +/- 12'24'' in subjects with chronic hepatitis and 65'30'' +/- 39'36'' in subjects with cirrhosis. The Tu parameter was found to be delayed more significantly in cirrhotic patients and less in subjects with acute or chronic hepatitis, compared to dyspeptics with normal haematochemical parameters. Te was significantly delayed in subjects with cirrhosis and acute hepatitis, while there was no difference for subjects with chronic hepatitis. Of the routine haematochemical tests, the albumin/gamma-globulin ratio and unconjugated bilirubin were found to correlate significantly with the Tu parameter, whereas conjugated bilirubin was found to bear a significant correlation to the Te parameter.

Sensitive detection of amino acids in human serum and dried blood disc of 3 mm diameter for diagnosis of inborn errors of metabolism.

Sensitive high-performance liquid chromatographic determination of amino and imino acids in human serum (5 microliters) and dried blood (2.6-2.8 microliters) on a paper disc (3 mm diameter) of normal and abnormal newborns with inborn errors of metabolism (phenylketonuria, maple syrup urine disease and tyrosinosis) is described. Amino and imino acids in the biological specimens were extracted with ethanol and derivatized with 4-fluoro-7-nitrobenzo-2-oxa-1,3-diazole at 60 degrees C and at pH 8.0 for 1 min. The fluorescent derivatives were separated on mu Bondapak C18 and detected fluorometrically (530 nm/470 nm). The method was about one order of magnitude more sensitive than the similar method using o-phthalaldehyde. The amino acid contents obtained by the proposed method were comparable to those obtained by the amino acid analyser with use of o-phthalaldehyde.