Liquid chromatography-mass spectroscopy in the diagnosis of biliary atresia in children with hyperbilirubinemia.

BACKGROUND: Biliary atresia (BA) is difficult to distinguish from other causes of cholestasis. We evaluated the use of liquid chromatography-mass spectroscopy (LC-MS) and bile acid profiles in the rapid, noninvasive diagnosis of BA. MATERIALS AND METHODS: Following Institutional Animal Care and Use Committee and Institutional Review Board approval, we used LC-MS to measure 26 bile acids in serum and stool samples from experimental models of BA and in urine, stool, and serum samples from non-cholestatic and cholestatic human infants. RESULTS: We first evaluated the utility of LC-MS to distinguish bile acid profiles between sham, bile duct ligation, and 3,5-diethoxycarbonyl-1,4-dihydrocollidine mouse models of BA. Serum bile acids were significantly higher and stool bile acids were significantly lower in experimental BA. Next, we evaluated samples from non-cholestatic, cholestatic non-BA, and BA infants. There was no significant difference between cholestatic non-BA and BA stool and urine samples. However, primary bile acids were significantly higher in BA versus cholestatic non-BA samples (128.1 ± 14.2 versus 61.2 ± 20.5 µM). In addition, the primary, conjugated bile acids glycochenodeoxycholic acid and taurochenodeoxycholic acid were significantly elevated in BA compared with cholestatic non-BA serum samples. Using a receiver operating characteristic curve, we found that a serum glycochenodeoxycholic acid concentration of 30 µM had a sensitivity of 100%, specificity of 83.3%, positive predictive value of 88.9%, and negative predictive value of 100% in the diagnosis of BA. CONCLUSIONS: Our data indicate that bile acid patterns can be used to distinguish experimental and human BA from non-cholestatic and, more importantly, cholestatic disease. This suggests that LC-MS may be useful in the accurate, rapid, and non-invasive diagnosis of BA.

Activation of RAAS in a rat model of liver cirrhosis: no effect of losartan on renal sodium excretion.

BACKGROUND: Liver cirrhosis is characterized by avid sodium retention where the activation of the renin angiotensin aldosterone system (RAAS) is considered to be the hallmark of the sodium retaining mechanisms. The direct effect of angiotensin II (ANGII) on the AT-1 receptor in the proximal tubules is partly responsible for the sodium retention. The aim was to estimate the natriuretic and neurohumoral effects of an ANGII receptor antagonist (losartan) in the late phase of the disease in a rat model of liver cirrhosis. METHODS: Bile duct ligated (BDL) and sham operated rats received 2 weeks of treatment with losartan 4 mg/kg/day or placebo, given by gastric gavage 5 weeks after surgery. Daily sodium and potassium intakes and renal excretions were measured. RESULTS: The renal sodium excretion decreased in the BDL animals and this was not affected by losartan treatment. At baseline the plasma renin concentration (PRC) was similar in sham and BDL animals, but increased urinary excretion of ANGII and an increase P-Aldosterone was observed in the placebo treated BDL animals. The PRC was more than 150 times higher in the losartan treated BDL animals (p < 0.001) which indicated hemodynamic impairment. CONCLUSIONS: Losartan 4 mg/kg/day did not increase renal sodium excretion in this model of liver cirrhosis, although the urinary ANGII excretion was increased. The BDL animals tolerated Losartan poorly, and the treatment induced a 150 times higher PRC.

Role of Na+/K+-ATPase in Natriuretic Effect of Prolactin in a Model of Cholestasis of Pregnancy.

Participation of Na+/K+-ATPase in the natriuretic effect of prolactin in a cholestasis of pregnancy model was investigated. The Na+/K+-ATPase activity in rat kidney medulla, where active sodium reabsorption occurs, decreased in the model of cholestasis of pregnancy and other hyperprolactinemia types compared with intact animals. This effect was not connected with the protein level of α1- and ß-subunits of Na+/K+-ATPase measured by Western blotting in the kidney medulla. Decrease in Na+/K+-ATPase activity in the kidney cortex was not significant, as well as decrease in the quantity of mRNA and proteins of the α1- and ß-subunits of Na+/K+-ATPase. There were no correlations between the Na+/K+-ATPase activity and sodium clearance, although sodium clearance increased significantly in the model of cholestasis of pregnancy and other hyperprolactinemia groups under conditions of stable glomerular filtration rate measured by creatinine clearance. We conclude that the Na+/K+-ATPase is not the only mediator of the natriuretic effect of prolactin in the model of cholestasis of pregnancy.

Tandem mass spectrometric determination of atypical 3ß-hydroxy-Δ5-bile acids in patients with 3ß-hydroxy-Δ5-C27-steroid oxidoreductase deficiency: application to diagnosis and monitoring of bile acid therapeutic response.

BACKGROUND: 3ß-Hydroxy-Δ(5)-C27-steroid oxidoreductase (HSD3B7) deficiency, a progressive cholestatic liver disease, is the most common genetic defect in bile acid synthesis. Early diagnosis is important because patients respond to oral primary bile acid therapy, which targets the negative feedback regulation for bile acid synthesis to reduce the production of hepatotoxic 3ß-hydroxy-Δ(5)-bile acids. These atypical bile acids are highly labile and difficult to accurately measure, yet a method for accurate determination of 3ß-hydroxy-Δ(5)-bile acid sulfates is critical for dose titration and monitoring response to therapy. METHODS: We describe a electrospray ionization LC-MS/MS method for the direct measurement of atypical 3ß-hydroxy-Δ(5)-bile acid sulfates in urine from patients with HSD3B7 deficiency that overcomes the deficiencies of previously used GC-MS methods. RESULTS: Separation of sulfated 3ß-hydroxy-Δ(5)-bile acids was achieved by reversed-phase HPLC in a 12-min analytical run. The mean (SE) urinary concentration of the total 3ß-sulfated-Δ(5)-cholenoic acids in patients with HSD3B7 deficiency was 4650 (1711) µmol/L, approximately 1000-fold higher than in noncholestatic and cholestatic patients with intact primary bile acid synthesis. GC-MS was not reliable for measuring 3ß-hydroxy-Δ(5)-bile acid sulfates; however, direct analysis of urine by fast atom bombardment mass spectrometry yielded meaningful semiquantitative assessment of urinary excretion. CONCLUSIONS: The tandem mass spectrometry method described here for the measurement of 3ß-hydroxy-Δ(5)-bile acid sulfates in urine can be applied to the diagnosis and accurate monitoring of responses to primary bile acid therapy in HSD3B7 patients.

Metabolomic investigation of cholestasis in a rat model using ultra-performance liquid chromatography/tandem mass spectrometry.

Metabolomics follows the changes in concentrations of endogenous metabolites, which may reflect various disease states as well as systemic responses to environmental, therapeutic, or genetic interventions. In this study, we applied metabolomic approaches to monitor dynamic changes in plasma and urine metabolites, and compared these metabolite profiles in Eisai hyperbilirubinemic rats (EHBR, an animal model of cholestasis) with those in the parent strain of EHBR - Sprague-Dawley (SD) rats - in order to characterize cholestasis pathophysiologically. Ultra-performance liquid chromatography/tandem mass spectrometry-based analytical methods were used to assay metabolite levels. More than 250 metabolites were detected in both plasma and urine, and metabolite profiles of EHBR differed from those of SD rats. The levels of antioxidative and cytoprotective metabolites, taurine and hypotaurine, were markedly increased in urine of EHBR. The levels of many bile acids were also elevated in plasma and urine of EHBR, but the extent of elevation depended on the particular bile acid. The levels of cytoprotective ursodeoxycholic acid and its conjugates were markedly elevated, while that of cytotoxic chenodeoxycholic acid remained unchanged, suggesting the balance of bile acids had shifted resulting in decreased toxicity. In EHBR, reduced biliary excretion leads to increased systemic exposure to harmful compounds including some endogenous metabolites. Our metabolomic data suggest that mechanisms exist in EHBR that compensate for cholestasis-related damage.

Urinary Elimination of Bile Acid Glucuronides under Severe Cholestatic Situations: Contribution of Hepatic and Renal Glucuronidation Reactions.

Biliary obstruction, a severe cholestatic complication, causes accumulation of toxic bile acids (BAs) in liver cells. Glucuronidation, catalyzed by UDP-glucuronosyltransferase (UGT) enzymes, detoxifies cholestatic BAs. Using liquid chromatography coupled to tandem mass spectrometry, 11 BA glucuronide (-G) species were quantified in prebiliary and postbiliary stenting serum and urine samples from 17 patients with biliary obstruction. Stenting caused glucuronide- and fluid-specific changes in BA-G levels and BA-G/BA metabolic ratios. In vitro glucuronidation assays with human liver and kidney microsomes revealed that even if renal enzymes generally displayed lower KM values, the two tissues shared similar glucuronidation capacities for BAs. By contrast, major differences between the two tissues were observed when four human BA-conjugating UGTs 1A3, 1A4, 2B4, and 2B7 were analyzed for mRNA and protein levels. Notably, the BA-24G producing UGT1A3 enzyme, abundant in the liver, was not detected in kidney microsomes. In conclusion, the circulating and urinary BA-G profiles are hugely impacted under severe cholestasis. The similar BA-glucuronidating abilities of hepatic and renal extracts suggest that both the liver and kidney may contribute to the urine BA-G pool.

Renal elimination of p-aminohippurate (PAH) in response to three days of biliary obstruction in the rat. The role of OAT1 and OAT3.

Pharmacokinetic studies of the drugs administered to subjects with mechanical cholestasis are scarce. The purpose of the present study was to examine the effects of bile duct ligation of 3 days (peak of elevation of serum bile acids and bilirubin) on the systemic and renal PAH clearance and on the expression of cortical renal OAT1 and OAT3 in a rat model. PAH is the prototypical substrate of the renal organic anion transport system. Male Wistar rats underwent a bile duct ligation (BDL rats). Pair-fed sham-operated rats served as controls. BDL rats displayed a significantly lower systemic PAH clearance. Renal studies revealed a reduction in the renal clearance and in the excreted and secreted load of PAH in BDL rats. The OAT1 protein expression in kidney homogenates was not modified, but it decreased in the basolateral membranes from BDL rats. In contrast, OAT3 abundance in both kidney cortex homogenates and in basolateral membranes increased by 3 days after the ligation. Immunocytochemical studies (light microscopic and confocal immunofluorescence microscopic analyses) confirmed the changes in the renal expression of these transport proteins. The present study demonstrates the key role of OAT1 expression in the impaired elimination of PAH after 3 days of obstructive cholestasis.

Simple and quantitative analysis of urinary sulfated tauro- and glycodihydroxycholic acids in infant with cholestasis by electrospray ionization mass spectrometry.

Here we report a simple, sensitive, and accurate method for detecting urinary sulfated tauro- and glyco-bile acids that uses electrospray ionization mass spectrometry. The sulfated tauro- and glycodihydroxycholic acids mainly generated [M-2H](2-) negative ions at m/z 288.6 and m/z 263.6, respectively. These doubly charged ions appeared primarily in samples prepared from the urine of patients with cholestasis and were detected quantitatively. Cholestatic jaundice is the primary clinical sign of biliary atresia. The measurement of doubly charged negative ions, especially of sulfated taurodihydroxycholic acid (principally taurochenodeoxycholate-3-sulfate), is a useful screening modality for biliary atresia in neonates.

Azithromycin may reduce cholestasis in primary sclerosing cholangitis: a case report and serendipitous observation.

The newer macrolides have been shown to exert additional anti-inflammatory effects. We report the possible effect of azithromycin on primary sclerosing cholangitis in a patient treated with the drug for severe asthma. A 45-year-old woman with Crohn?s disease and primary sclerosing cholangitis, also suffering from severe asthma, was treated with azithromycin 500 mg OD for 3 consecutive days a week because of the clinical suspicion of bronchiectasis and the severity of her asthma. When the therapy was discontinued, her urine again became darker, pruritus reappeared with the usual severity and laboratory parameters, evaluated after 6 weeks without azithromycin, also worsened. For these reasons macrolide treatment was re-established. Cholestasis-related symptoms and the dark colour of the urine were again reduced 6 weeks later and laboratory parameters were again reversed. We are therefore tempted to speculate that azithromycin may have an effect on primary sclerosing cholangitis on the basis of its anti-inflammatory properties.

Elevation of free beta subunit of human choriogonadotropin and core beta fragment of human choriogonadotropin in the serum and urine of patients with malignant pancreatic and biliary disease.

Human choriogonadotropin (hCG), its free beta subunit (beta hCG), and the core beta hCG fragment (c beta hCG) were measured by highly sensitive time-resolved immunofluorometric assays in the serum and urine of 29 patients with pancreatic cancer, 7 patients with biliary cancer, and 45 patients with benign pancreatic or biliary diseases. The results were compared with those of an age- and sex-matched reference population of nonpregnant women and men. Of the various forms of hCG assayed in serum, beta hCG showed the best diagnostic accuracy, and c beta hCG was the best marker in urine. Elevated serum concentrations of beta hCG were observed in 72% of the patients with pancreatic cancer, in 6 of 7 patients with biliary cancer, and in 9% of those with benign disorders. The serum concentrations of c beta hCG were elevated in 45%, 57%, and 2%, respectively, and those in urine in 55%, 71%, and 11%, respectively. The molar concentrations of c beta hCG in serum were mostly lower than those of beta hCG. Thus beta hCG secreted into serum appears to be the main source of c beta hCG in urine. Provided that they are measured by sufficiently sensitive and specific assays, beta hCG in serum and c beta hCG in urine appear to be useful markers for pancreatic and biliary cancer.

The urinary excretion of glucosiduronates of cortisol and cortisone.

Cortisol and cortisone glucosiduronic acids were synthesised in a 14C-labelled from and utilised in a double-isotope derivative procedure for the analysis of cortisol glucosiduronate (FG) and cortisone glucosiduronate (EG) in human urine. Normal adults were found to excrete between 16 and 100 mug/24 h of FG (n = 14) and between 55 and 120 mug/24 h of EG (n = 15). Elevated values were observed in subjects with Cushing's syndrome and following ACTH stimulation. Abnormal excretion was noted in one patient with hepatic cirrhosis and in one case of cholestatic jaundice. The ratio FG/EG was markedly increased after ACTH stimulation and, in the normal group, was positively correlated to a highly significant degree (P less than 0.001) with FG excretion. These two observations suggest that EG excretion is less sensitive than FG excretion to variations in cortisol production.

Urinary excretion of bile acids in bile duct-ligated rats.

BACKGROUND: In patients with complete bile duct obstruction, the only pathway of bile acid elimination is through the urine. However, the urinary excretion of various bile acid conjugates in the presence of bile duct obstruction has not been clarified. Given this factor, the urinary excretion of various bile acids was compared in rats that were bile duct-ligated for 3 days. METHODS: After urinary bladder cannulation, radiolabeled bile acids were intravenously injected, and urine samples were collected every 2 h for 6 h, and radioactivity was counted. RESULTS: Urinary excretion (cumulative percent dose during 6 h) of taurocholate and cholate was similar (19.3% and 16.8%). Urinary excretion of tauroursodeoxycholate, lithocholate, and taurolithocholate-sulfate was less effective (12.7%, 9.8% and 2.1%, respectively). Cholate was mostly conjugated with taurine, and lithocholate was mostly conjugated with taurine and further hydroxylated. CONCLUSIONS: These results indicate that unconjugated bile acids were taken up by the liver and excreted into the blood after further biotransformation even under conditions of complete bile duct obstruction. Although bile acid sulfates are the major bile acids in the urine of patients with obstructive jaundice, monohydroxylated bile acids are considered not to be so effectively excreted into the urine, even with conjugation with taurine and sulfate, in rats.

Cysteinyl leukotrienes in the bile of patients with obstructive jaundice.

BACKGROUND: Cysteinyl leukotrienes (LTs) are potent proinflammatory mediators. They are predominantly excreted from blood by hepatobiliary elimination. To explore the clinical significance of biliary cysteinyl LTs, we determined their concentration changes in bile during treatment in patients with obstructive jaundice. METHODS: Bile samples were obtained during endoscopic or transhepatic biliary drainage. Leukotrienes C(4), D(4), and E(4) were quantified by two-step reversed-phase high-performance liquid chromatography and subsequent radioimmunoassay. RESULTS: The increased excretion of cysteinyl LTs (LTC(4) + LTD(4) + LTE(4)) decreased between day 1 and 14 after drainage (means, 171 pmol/h to 79 pmol/h; P < 0.02). During drainage, the excretion was higher when there was additional cholangitis (mean, 225 and 86 pmol/h, with and without cholangitis, respectively; P < 0.001). The concentrations of LTD(4) and LTE(4) were also higher with additional cholangitis than without (LTD(4), mean 6.0 vs 2.0 nM; P < 0.05; LTE(4), 6.8 vs 2.4 nM; P < 0.02, respectively). Biliary LTC(4) was detected only in patients with cholangitis. The biliary excretion of cysteinyl LTs was positively correlated with leukocyte concentration ( r = 0.68; P < 0.005) and C-reactive protein ( r = 0.73; P < 0.005) in blood. Furthermore, only in the absence of cholangitis, the excretion was positively correlated with serum gamma-glutamyl transferase ( r = 0.76; P < 0.02) and alanine aminotransferase ( r = 0.72; P < 0.02). CONCLUSIONS: The excretion of biliary cysteinyl LTs increases with the severity of cholestasis and hepatic inflammation in patients with obstructive jaundice. An additional increase of cysteinyl LTs was observed during bacterial cholangitis. The increased biliary excretion of biologically active cysteinyl LTs may contribute to the aggravation of cholestasis and inflammatory reaction in obstructive jaundice.

Analysis of bile acid glucuronides in urine: group separation on a lipophilic anion exchanger.

A chromatographic separation of glucuronidated bile acids using the anion exchanger diethylaminohydroxypropyl Sephadex LH-20 (DEAP LH-20) is described. Group separation of non-sulfated, non-glucuronidated bile acids, bile acid glucuronides, bile acid monosulfates, and bile acid disulfates was obtained. The method allowed analysis of all these bile acid derivatives in the urine of 15 patients with cirrhosis of the liver and cholestasis. The patients excreted in mean 30.4 mumol/24 h non-sulfated, non-glucuronidated bile acids, 90.3 mumol bile acid monosulfates, and 10.2 mumol bile acid glucuronides. Glycine- or taurine-conjugated were 68% of the non-sulfated, non-glucuronidated bile acids, 96% of bile acid sulfates, and 81% of bile acid glucuronides.

Urinary bile alcohol profiles in healthy and cholestatic children.

BACKGROUND: Bile alcohols are normal constituents of urine. METHODS: To better understand bile alcohol profile in childhood, urinary specimens from 41 healthy children and 10 children with cholestasis, and 3 healthy adults, were analyzed by GLC and GC-MS. RESULTS: Five bile alcohols, 27-nor-5beta-cholestane-3alpha,7alpha,12alpha,24S,25R-pentol, 5beta-cholestane-3alpha,7alpha,12alpha,24S, 25-pentol, 5beta-cholestane-3alpha,7alpha,12alpha,24S,26-pentol, 5beta-cholestane-3alpha,7alpha, 12alpha,25,26-pentol, and 5beta-cholestane-3alpha,7alpha,12alpha,26,27-pentol were identified in all specimens. C(26)-Pentol was the most abundant constituent, constituting 29.5 to 65% of bile alcohols. Among healthy children (n=41), no significant relationship was seen between proportions of the C(26)-pentol and age, but older children (n=15, 6 to 14 years) showed a significantly greater mean percentage of the C(26)-pentol than young children (n=26, 0 to 5 years; 58.1+/-4.23% vs. 46.0+/-9.24%, p<0.001). In children with cholestatic liver diseases, the percentage of C(26)-pentol in urinary bile alcohols was significantly lower than age-matched controls. CONCLUSIONS: There is an increased composition of C(26)-pentol in older children and relatively decreased composition of C(26)-pentol in children with cholestatic liver diseases.

Identification of 3,6,7,12-tetrahydroxy-5 beta-cholan-24-oic acids in human biologic fluids.

Unusual bile acids, 3 alpha, 6 alpha, 7 alpha, 12 alpha-, and 3 alpha, 6 beta, 7 beta, 12 alpha-tetrahyroxy-5 beta-cholan-24-oic acids, were identified in all amniotic fluid (four samples) and urine (six samples) from adult patients with cholestatic liver disease by gas-liquid chromatography/mass spectrometry. For the certain identification of these bile acids in the biologic samples, the chemical syntheses of 3 alpha, 6 beta, 7 alpha, 12 alpha- and 3 alpha, 6 beta, 7 beta, 12 alpha-tetrahydroxy-5 beta-cholan-24-oic acids were conducted.

Radioimmunoassay of urinary 3 beta-hydroxy-5-cholenoyl glycine in hepatobiliary disease.

A radioimmunoassay for 3 beta-hydroxy-5-cholenoyl glycine in human urine has been developed. The antiserum was elicited with the antigen in which the steroid hapten is linked to a bovine serum albumin through the C-19 position. The [125I]-tyrosine derivative of the hapten was used as radioligand. The standard curves were linear ranging from 10 to 320 ng/mL. The cross-reactivities with other bile acids were not detectable and below 0.3% with cholesterol. Sample preparation includes extraction of 3 beta-hydroxy-5-cholenoyl glycine from urine and solvolysis of the sulfates--main form present in urine. Urinary excretion of 3 beta-hydroxy-5-cholenoyl glycine was 0.373 +/- 0.133 mumol/day in healthy adults. Urinary excretion of 3 beta-hydroxy-5-cholenoyl glycine increased in chronic liver dysfunction, hepatoma and obstructive jaundice in this order.

No evidence of enterohepatic circulation of doxorubicin in a patient with transitory biliary obstruction due to lymphoblastic lymphoma.

Doxorubicin (DOX) and doxorubicinol (DOXOL) were analyzed by high performance liquid chromatography in serum, bile and urine in a lymphoma patient with tumor-induced biliary obstruction. The patient had an indwelling T-tube and was given DOX containing combination chemotherapy. The bile was collected via the T-tube and given orally (together with beer) to the patient four times daily. New samples were obtained three weeks later when normal bile flow was re-established. The serum and bile concentration curves for DOX and DOXOL show great similarity between the first and second chemotherapy course, respectively. This finding strongly argues against an enterohepatic circulation of DOX or DOXOL of clinical importance in man.

Determination of 3ß-hydroxy-Δ5-bile acids and related compounds in biological fluids of patients with cholestasis by liquid chromatography-tandem mass spectrometry.

A method for the determination of conjugated and unconjugated 3ß-hydroxy-Δ5-bile acids and related bile acids in human urine and serum has been developed using high-performance liquid chromatography electrospray ionization-tandem mass spectrometry. Calibration curves for the bile acids were linear over the range of 10 2000 pmol/mL, and the detection limit was less than 4 pmol/mL for all bile acids using selected reaction monitoring analysis. The bile acids in urine and serum samples from two patients with severe cholestatic liver disease were measured by this analytical method. Glycine-conjugated 3ß-hydroxy-Δ5-bile acid 3-sulfates were determined to be the major bile acids in the urine and serum from patients with a 3ß-hydroxy-Δ5-C27-steriod dehydrogenase/isomerase deficiency or dysfunction.

Role of glucuronidation for hepatic detoxification and urinary elimination of toxic bile acids during biliary obstruction.

Biliary obstruction, a severe cholestatic condition, results in a huge accumulation of toxic bile acids (BA) in the liver. Glucuronidation, a conjugation reaction, is thought to protect the liver by both reducing hepatic BA toxicity and increasing their urinary elimination. The present study evaluates the contribution of each process in the overall BA detoxification by glucuronidation. Glucuronide (G), glycine, taurine conjugates, and unconjugated BAs were quantified in pre- and post-biliary stenting urine samples from 12 patients with biliary obstruction, using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The same LC-MS/MS procedure was used to quantify intra- and extracellular BA-G in Hepatoma HepG2 cells. Bile acid-induced toxicity in HepG2 cells was evaluated using MTS reduction, caspase-3 and flow cytometry assays. When compared to post-treatment samples, pre-stenting urines were enriched in glucuronide-, taurine- and glycine-conjugated BAs. Biliary stenting increased the relative BA-G abundance in the urinary BA pool, and reduced the proportion of taurine- and glycine-conjugates. Lithocholic, deoxycholic and chenodeoxycholic acids were the most cytotoxic and pro-apoptotic/necrotic BAs for HepG2 cells. Other species, such as the cholic, hyocholic and hyodeoxycholic acids were nontoxic. All BA-G assayed were less toxic and displayed lower pro-apoptotic/necrotic effects than their unconjugated precursors, even if they were able to penetrate into HepG2 cells. Under severe cholestatic conditions, urinary excretion favors the elimination of amidated BAs, while glucuronidation allows the conversion of cytotoxic BAs into nontoxic derivatives.