The clinical importance of conventional and quantitative liver function tests in liver transplantation

The advantages and disadvantages of using monoethylglycinexylidide (MEGX), the major metabolite of lidocaine, as a probe of hepatic function in liver transplantation are reviewed. A 'real time' test of liver function should give a measure of current hepatocellular capacity rather than reflect past damage. The hepatic metabolism of lidocaine to MEGX is the basis of a flow-dependent dynamic test of liver function. In pre-transplantation patients, data from this MEGX test support its role in assessing the risk of morbidity and mortality. In assessing the liver transplant donor, there are differences concerning its apparent usefulness and these must be resolved. In the liver transplant recipient, this MEGX test is also useful for measuring real-time hepatic metabolizing activity, and low MEGX values reflect the clinical condition of the patient. At present, however, this test has several limitations. Therefore, a comprehensive evaluation, not only by the MEGX test but also by a combination of other conventional liver function tests (biochemical parameters, etc.), or with histological evaluation, is thought to be desirable for deciding whether a liver transplantation should be carried out or not.

The monoethylglycinexylidide test does not impair psychometric performance in patients with chronic hepatitis or cirrhosis

Lidocaine (LID) is an aminoethylamide used in hepatology to perform the monoethylglycinexylidide (MEGX) test for the evaluation of liver function in patients with cirrhosis (CIR) or chronic hepatitis (CH). The authors evaluated whether the MEGX test changes psychometric performance in patients with chronic liver disease and, in particular, whether it might trigger subclinical portosystemic encephalopathy in patients with CIR. Thirty patients with CIR and 20 patients with CH were studied. They underwent a standard-dose MEGX test, before and after which a psychometric test was administered and blood pressure, heart rate, and adverse effects were recorded. The MEGX test did not modify psychometric performance. Mean arterial blood pressure and heart rate did not change at the end of the MEGX test in either patients with CH or CIR. Adverse effects were present in 66% of all patients during lidocaine injection and lasted up to 3 minutes afterwards. They were more frequent in patients with CH than in patients with CIR (85% vs 53%). No relationship was found between adverse effects and lidocaine dosage, nor between adverse effects and MEGX or lidocaine concentration at 15 minutes. Standard-dose MEGX test does not worsen or trigger portosystemic encephalopathy in CIR. Adverse effects were frequent but mild.

Concentrations of lidocaine and monoethylglycine xylidide in brain, cerebrospinal fluid, and plasma during lidocaine-induced epileptiform electroencephalogram activity in rabbits: the effects of epinephrine and hypocapnia

When injecting lidocaine into tissues, the mean toxic dose of lidocaine may be increased by adding epinephrine to lidocaine and by decreasing the PaCO(2). In contrast, when lidocaine is introduced directly into an artery or vein, adding epinephrine to lidocaine may decrease the mean toxic dose of lidocaine. Less is known about the effects of decreased PaCO(2) on intravascular lidocaine toxicity. We infused lidocaine in 24 rabbits at 4 mg. kg(-1). min(-1) with/without epinephrine and with/without hypocapnia. We measured the time to onset of lidocaine-induced seizures, total dose of lidocaine at the time of seizures, and concentrations of lidocaine and monoethylglycine xylidide (MEGX), a metabolite of lidocaine, in plasma, brain, and cerebrospinal fluid. Epinephrine decreased onset time by 11% with hypocapnia and by 21% with normocapnia, and it increased plasma MEGX by 1 microg/mL with hypocapnia and 2 microg/mL with normocapnia. Hypocapnia increased onset time by 18% without epinephrine and by 33% with epinephrine, and it increased whole-brain MEGX by 10 microg/mL without epinephrine and by 14 microg/mL with epinephrine. We conclude that, when lidocaine is given intravascularly, hypocapnia increases onset time and lidocaine dose required for seizures. These effects occur with no change in the concentration of lidocaine in plasma or the brain.

IMPLICATIONS

Hypocapnia increases the toxic dose of lidocaine given IV without altering lidocaine concentrations in blood, brain, or cerebrospinal fluid. Whole-brain monoethylglycine xylidide concentration is greater during hypocapnia than during normocapnia, and the addition of epinephrine to lidocaine increases the concentration of monoethylglycine xylidide in plasma.

[Determination of lidocaine in human spinal cord by high-performance liquid chromatography]

A RPHPLC method for determining lidocaine in human's spinal cord. Was established. The linear range of the method was 0.20-20.0 micrograms/ml(r = 0.9999). The detection limit was 0.02 ng/ml(S/N > or = 3) and the clean-up recovery of lidocaine in human spinal cord was 82.4%-92.7%. The CV% were no more than 6.0% (N = 4). No interfere by other compounds was observed in study results using this method. RPHPLC method shows an excellent recovery, high sensitivity and good precision.

Histologic determinants of monoethylglycinexylidide formation in patients with chronic hepatitis C

Patients affected by chronic hepatitis C (CHC) display a peculiar histologic picture characterized by the presence of steatosis and bile duct damage in addition to evidence of inflammation, necrosis, and fibrosis. In the staging of these patients, functional evaluation may be considered a complementary tool. The monoethylglycinexylidide (MEGX) test has been used in diagnostic and prognostic assessment of chronic liver disease as a quantitative liver function test. In this study the authors evaluated whether different sampling times for the test could reflect different histologic patterns. The authors studied 82 patients with biopsy-proven CHC who underwent functional evaluation by means of MEGX test. The authors found that MEGX15 better reflected the histologic findings of necrosis and inflammation, and MEGX60 the presence of fibrosis. Neither steatosis nor bile duct damage showed a strong correlation with either sampling time. Moreover, MEGX levels showed a progressive decrease as histologic grading of chronic hepatitis progressively increased. Stepwise regression analysis identified necrosis and inflammation as histologic variables associated with both MEGX15 and MEGX30, and fibrosis as a variable associated with MEGX60. These results suggest that a decline in liver metabolic function corresponds to a progressive increase in liver damage, and that this circumstance should be taken into account when prescribing drugs to patients with CHC.

Determination of lidocaine in hair of drug fatalities by headspace solid-phase microextraction

The local anesthetic lidocaine was determined in hair by hydrolysis of the samples with 4% NaOH in the presence of excessive Na2SO4 and subsequent headspace solid-phase microextraction with a 65-microm Carbowax/divinylbenzene fiber, and gas chromatography-mass spectrometry measurement with etidocaine as the internal standard. The calibration curve was linear between 0.1 and 1000 ng/mg. The detection and quantitation limits were 0.1 and 0.4 ng/mg, respectively. The method was applied to hair samples of 49 drug fatalities, and positive results were obtained in 32 cases with lidocaine concentrations between 0.4 and 400 ng/mg and 675 ng/mg in one extreme case. For comparison, morphine, 6-acetylmorphine, codeine, dihydrocodeine, methadone, cocaine, and benzoylecgonine were also determined by usual methods. From segmental investigations in four of the cases and from comparison with the hair concentrations of the other drugs, it follows that lidocaine was consumed for a longer period of time as an adulterant of cocaine and heroin preparations.

Simultaneous determination of lignocaine hydrochloride and phenylephrine hydrochloride by HPTLC

A high performance thin layer chromatographic (HPTLC) method for the simultaneous quantification of lignocaine hydrochloride (LIG) and phenylephrine hydrochloride (PHE) is described. The mobile phase consisted of ethyl acetate-methanol ammonia (4:1:0.4 v/v/v). The densitometric determination of LIG and PHE was carried out at 262 nm and 291 nm, respectively. The calibration curves of LIG and PHE were linear in the range of 8-18 microg and 4-9 microg, respectively. The method was validated with respect to system precision, method precision, recoveries, intra-day and inter-day variation. The system was applied for the simultaneous determination of LIG and PHE from a new drug delivery system. The results indicate that the method is simple, specific, selective and reliable for simultaneous quantitative determination of LIG and PHE as bulk drug and from formulations.

Low-dose dopexamine in patients undergoing hemihepatectomy: an evaluation of effects on reduction of hepatic dysfunction and ischaemic liver injury

BACKGROUND

Hepatic dysfunction is a common problem in patients after hemihepatectomy. Treatment with low-dose dopamine has been shown to be beneficial in hemihepatectomy patients. We hypothesized that dopexamine, a synthetic vasoactive catecholamine, due to its specific pharmocodynamic profile may be more effective in reducing hidden ischaemic episodes in the hepato-splanchnic region during and after temporary total cross-clamping of hepatic inflow in these patients.

METHODS

The effects of low-dose dopexamine on hepatic venous haemoglobin oxygen saturation (ShvO2), hepatic venous lactate level, monoethylglycinxylid (MEGX) formation, hepatic synthetic function and indicators for hepatic cell damage were studied during hemihepatectomy and for 16 h postoperatively in hemihepatectomy patients and compared to those of low-dose dopamine. In a prospective, double-blind clinical study 20 patients received randomly either dopexamine (DPX) 0.5 microg kg(-1) min(-1) (n=10) or dopamine (DO) 2.5 microg kg(-1) min(-1) (n= 10). Infusions were started after induction of anaesthesia and continued 16 h postoperatively. Hepatic vein, radial and pulmonary artery were catheterized. Measurements were carried out after induction of anaesthesia, after total cross-clamping of hepatic inflow, and at 2 h and 16 h postoperatively.

RESULTS

There were no differences in systemic haemodynamics, oxygenation, ShvO2, serum aminotransferases or MEGX levels between the groups. At 16 h postoperatively prothrombin and antithrombin III levels were significantly lower while hepatic venous lactate was significantly higher in the DPX group compared to the DO group.

CONCLUSION

In patients undergoing hemihepatectomy, we could not reveal superior hepatoprotective effects of low-dose dopexamine compared to low-dose dopamine.

Storage of partially deacetylated chitosan films

Chitosan has wide-ranging applications as a biomaterial, but its stability in storage is not widely known. The objective of this study was to evaluate the storage stability of films prepared from chitosan of 77% deacetylation. Both the neutralized and acetate films were evaluated, as chitosan salts offer the advantage of being soluble in water at the neutral-to-basic pH range. Aqueous solutions containing 0.5-5% acetic acid were used as solvents. The X-ray diffraction pattern, the IR spectrum, water uptake, and solubility of the films were influenced by the presence of the N-acetyl functionality, the acetate ions, and storage of the films. The anhydrous chitosan crystal in the neutralized films was unstable to storage at 4 degrees C and 28 degrees C. Its formation, as well as that of the hydrated crystal, were further hindered by the presence of even small quantities of the acetate ions. The resultant amorphous nature of the acetate films, coupled with the acidifying action of the acetic acid, led to greater water uptake and solubility compared to the neutralized films. Storage reduced the differences between the neutralized and acetate films. It also minimized the influence of the initial acetic acid content on the IR absorption and water uptake of the acetate films, exerting its leveling effects mainly within the first week of storage. Using a lower storage temperature of 4 degrees C or heating the films for 2 h at 120 degrees C prior to storage did not significantly modify the results. A pertinent factor appears to be the degree of deacetylation of the chitosan that was used to prepare the films.

Use of headspace solid-phase microextraction (HS-SPME) in hair analysis for organic compounds

Headspace solid phase microextraction (HS-SPME) has advantages of high purity of the extract, avoidance of organic solvents and simple technical manipulation and can be used in combination with gas chromatography-mass spectrometry (GC-MS) in the hair analysis of a number of drugs. HS-SPME coupled with the hydrolysis of the hair matrix by 4% sodium hydroxide in the presence of excess sodium sulphate and of a suitable internal standard proved to be a convenient one-step method for the measurement of many lipophilic basic drugs such as nicotine, amphetamine derivatives, local anaesthetics, phencyclidine, ketamine, methadone, diphenhydramine, tramadol, tricyclic antidepressants and phenothiazines. Detection limits were between 0.05 and 1.0 ng/mg. From spiked 10-mg hair samples absolute recoveries between 0.04 and 5.7% were found. These recoveries decreased considerably if larger sample amounts were used, perhaps due to increased drug solubility in the aqueous phase or to elevated viscosity in the presence of dissolved hair proteins. Because of the phenolic hydroxyl group a change of pH after alkaline hair digestion (by adding excess orthophosphoric acid) was necessary for the detection of delta 9-tetrahydrocannabinol (delta 9-THC), cannabinol (CBN) and cannabidiol (CBD) by HS-SPME. Nevertheless, the detection limits were such that only CBN could be detected in hair of a consumer. Clomethiazole, a compound hydrolysed in alkali, was measured by HS-SPME after extraction with aqueous buffer. The detection limit was 0.5 ng/mg. Cocaine could not be detected by HS-SPME. The application of HS-SPME to hair samples from several forensic and clinical cases is described.

Effect of endotoxin shock on the clearance of lidocaine and indocyanine green in the perfused rat liver

Endotoxin administration and cecal ligation and puncture produce significant hepatocellular dysfunction when studied in vivo. Specific factors that are present in vivo after endotoxin administration and cecal ligation and puncture, such as alterations in liver blood flow, circulating mediators, and hypoxia, can alter hepatic function. In this study, we used an isolated perfused liver to evaluate the effects of in vivo administration of endotoxin on hepatic function using indocyanine green (ICG) as a global marker of function and lidocaine and its metabolite, MEGX, as specific markers of the CYP450 enzyme system. Endotoxin (Escherichia coli; 45 mg/kg i.p.) was administered to rats followed by a 6-h monitoring before preparation of the isolated in situ perfused liver. Livers from control and endotoxin groups received either ICG (control, n = 6; endotoxin, n = 5) or lidocaine (control, n = 8; endotoxin, n = 8). A separate group of rats (n = 6) received cimetidine (an inhibitor of the CYP450 enzyme system) at a dose of 80 mg/kg daily for 3 days. Livers were perfused via the portal vein by using a single-pass system with a balanced salt solution 6 h after receiving either endotoxin or saline or 24 h after receiving the last dose of cimetidine. After a 40-min stabilization period, ICG or lidocaine was infused via the portal vein until steady-state concentrations were reached in the venous outflow. The total hepatic clearance and intrinsic hepatic clearance for ICG and lidocaine were unchanged in the livers obtained from endotoxin-treated rats. This model could adequately detect CYP450 inhibition because cimetidine-treated rats had significantly lower initial MEGX concentrations (0.63 +/- 0.03 mg/L) compared with control (0.77 +/- 0.03 mg/L) and endotoxin-treated (0.74 +/- 0.04 mg/L) rats. Septic livers had significantly higher initial hepatic oxygen consumption (HVO2) than did control livers (45 +/- 3 microL/min/g vs 82 +/- 9 microL/min/g). The HVO2 remained higher in the septic livers and significantly increased throughout the study, which demonstrated that the livers remained viable and functional. These data indicate that there is no detectable hepatocellular dysfunction after endotoxin shock using ICG, lidocaine, and MEGX in the isolated perfused liver; therefore the dysfunction reported from in vivo studies may be reversible when the liver is removed from the shocked environment.

Fluvoxamine is a more potent inhibitor of lidocaine metabolism than ketoconazole and erythromycin in vitro

CYP3A4 is generally believed to be the major CYP enzyme involved in the biotransformation of lidocaine in man; however, recent in vivo studies suggest that this may not be the case. We have examined the effects of the CYP3A4 inhibitors erythromycin and ketoconazole and the CYP1A2 inhibitor fluvoxamine on the N-deethylation, i.e. formation of monoethylglycinexylidide (MEGX), and 3-hydroxylation of lidocaine by human liver microsomes. The experiments were carried out at lidocaine concentrations of 5 microM (clinically relevant concentration) and 800 microM. The formation of both MEGX and 3-hydroxylidocaine was best described by a two-enzyme model. At 5 microM of lidocaine, fluvoxamine was a potent inhibitor of the formation of MEGX (IC50 1.2 microM). Ketoconazole and erythromycin also showed an inhibitory effect on MEGX formation, but ketoconazole (IC50 8.5 microM) was a much more potent inhibitor than erythromycin (IC50 200 microM). At 800 microM of lidocaine, fluvoxamine (IC50 20.7 microM) and ketoconazole (IC50 20.4 microM) displayed a modest inhibitory effect on MEGX formation, whereas erythromycin was a weak inhibitor (IC50 >250 microM). The 3-hydroxylation of lidocaine was potently inhibited by fluvoxamine at both lidocaine concentrations (IC50 0.16 microM at 5 microM and 1.8 microM at 800 microM). Erythromycin and ketoconazole showed a clear inhibitory effect on the 3-hydroxylation of lidocaine at 5 microM of lidocaine (IC50 9.9 microM and 13.9 microM, respectively), but did not show a consistent effect at 800 microM of lidocaine (IC50 >250 microM and 75.0 microM, respectively). Although further studies are needed to elucidate the role of distinct CYP enzymes in the biotransformation of lidocaine in humans, the findings of this study suggest that while both CYP1A2 and CYP3A4 are involved in the metabolism of lidocaine by human liver microsomes, CYP1A2 is the more important isoform at clinically relevant lidocaine concentrations.

Deaths related to liposuction

BACKGROUND

The technique of tumescent liposuction involves the subcutaneous infusion of a solution containing lidocaine, followed by the aspiration of fat through microcannulas. Although the recommended doses of lidocaine are as high as 55 mg per kilogram of body weight, few safety data are available. Since reporting of adverse events associated with tumescent liposuction is not mandatory, the incidence of complications and deaths is unknown.

METHODS

We identified 5 deaths after tumescent liposuction among 48,527 deaths referred to the Office of Chief Medical Examiner of New York City between 1993 and 1998. The patients' records and postmortem examination results were reviewed to identify common contributory factors.

RESULTS

The five patients had received lidocaine in doses ranging from 10 to 40 mg per kilogram. Other drugs, such as midazolam, were also administered. Three patients died as a result of precipitous intraoperative hypotension and bradycardia with no definitively identified cause. Postmortem blood lidocaine concentrations in two of the patients were 5.2 and 2 mg per liter. One patient died of fluid overload, and one died of deep venous thrombosis of calf veins with pulmonary thromboembolism after tumescent liposuction of the legs.

CONCLUSIONS

Tumescent liposuction can be fatal, perhaps in part because of lidocaine toxicity or lidocaine-related drug interactions.

Immobilized artificial membrane (IAM)-HPLC for partition studies of neutral and ionized acids and bases in comparison with the liposomal partition system

PURPOSE

To study the partitioning of model acids ((RS)-warfarin and salicylic acid), and bases (lidocaine, (RS)-propranolol and diazepam), with immobilized artificial membrane (IAM)-HPLC, as compared to partitioning in the standardized phosphatidylcholine liposome/buffer system.

METHODS

The pH-dependent apparent partition coefficients D were calculated from capacity factors (k'IAM) obtained by IAM-HPLC, using a 11-carboxylundecylphosphocholine column. For lipophilic compounds k'IAM, values were determined with organic modifiers and extrapolation to 100% water phase (k'IAMw) was optimized. Temperature dependence was explored (23 to 45 degrees C), and Gibbs free energy (deltaG), partial molar enthalpy (deltaH) and change in entropy (deltaS) were calculated. Equilibrium dialysis was used for the partitioning studies with the liposome/buffer system.

RESULTS

For extrapolation of k'IAMw, linear plots were obtained both with the respective dielectric constants and the mole fractions of the organic modifier. All tested compounds showed a similar pH-D diagram in both systems; however, significant differences were reproducibly found in the pH range of 5 to 8. In all cases, deltaG and deltaH were negative, whereas deltaS values were negative for acids and positive for bases.

CONCLUSIONS

In both partitioning systems, D values decreased significantly with the change from the neutral to the charged ionization state of the solute. The differences found under physiological conditions, i.e. around pH 7.4, were attributed to nonspecific interactions of the drug with the silica surface of the IAM column.

Characterization of lidocaine metabolism by rat nasal microsomes: implications for nasal drug delivery

Lidocaine has been recently approved for use as an intranasal spray in the treatment of migraine. In this study, we investigated the metabolism of lidocaine to its primary metabolite monoethylglycine xylidide (MEGX), by rat nasal olfactory and respiratory microsomes. The metabolic parameters were compared with metabolism employing rat and human hepatic microsomes. The olfactory and respiratory microsomes both exhibited considerable activity for conversion of lidocaine to MEGX in comparison with the activity in the hepatic tissues. The rat olfactory microsomes had a markedly higher affinity than the rat hepatic or respiratory microsomes. However, the turnover rate was only about one-half that of rat liver. Employing Western immunoblotting we investigated the presence of cytochrome P450s (CYPs) 1A2, 3A2, 2B1 and 2C11 in rat nasal tissues; these isozymes are known to partcipated in the metabolism of lidocaine in rat liver. These isozymes were found to be present in significant amounts in both the nasal olfactory and respiratory tissue; this is the first known report of the presence of CYP2C11 in nasal mucosae. Our studies underscore the importance of CYP-mediated drug metabolism in nasal tissues. The effect of this 'nasal first-pass' should be weighed carefully while considering the fate and the bioavailability of drugs delivered via the intranasal route.

Excretion of lidocaine and bupivacaine in breast milk following epidural anesthesia for cesarean delivery

BACKGROUND

There is a lack of information and knowledge about the practical importance of even low concentrations of the excretion of local anesthetics into breast milk, particularly concerning bupivacaine. The present work aims to confirm, under practical clinical conditions of admission of parturients, the passage of local anesthetics (lidocaine and bupivacaine) into breast milk after an epidural anesthesia.

METHODS

Twenty-seven pregnant women admitted for cesarean delivery received epidural anesthesia with 0.5% bupivacaine and 2% lidocaine. Blood and milk samples were simultaneously collected at 2, 6 and 12 h after the beginning of the epidural infusion. Lidocaine, bupivacaine and its main metabolite, pipecolylxylidide (PPX), were determined in serum and milk by a gas-liquid chromatographic technique. APGAR scores were systematically performed at delivery and a clinical examination was done 24 h after delivery.

RESULTS

Our data indicate that lidocaine and bupivacaine as well as PPX are excreted into breast milk. The milk/serum ratio based upon area under the curve values were 1.07 +/- 0.82, 0.34 +/- 0.24 and 1.37 +/- 0.61 mean +/- SD for lidocaine, bupivacaine and PPX, respectively. Most of the newborns had a maximal APGAR score. Our study does not reveal any adverse reactions related to the excretion of local anesthetics into breast milk.

CONCLUSION

This study documents the magnitude of excreted lidocaine, bupivacaine and PPX in breast milk, and indicates that the use of both lidocaine and bupivacaine for epidural anaesthesia is safe with regard to breast-feeding.

The lignocaine metabolite (MEGX) liver function test and P-450 induction in humans

AIMS

The N-deethylation of lignocaine to monoethylglycinexylidide (MEGX) is partially catalysed by the rifampicin inducible P-450 isoenzyme CYP3A4. This has led to the use of the MEGX test (MEGX plasma concentrations after i.v. lignocaine) as a marker of CYP3A4 activity. To test this hypothesis, we studied lignocaine and MEGX plasma pharmacokinetics.

METHODS

Ten healthy volunteers received rifampicin (600 mg day(-1)) for 6 days, resulting in a four- to sixfold increase in urinary 6beta-hydroxycortisol output. On days 1 and 7 (pretreatment), day 11 (treatment), and day 14 (48 h after rifampicin), 50 mg lignocaine i.v. was administered. MEGX concentrations at 30 min [MEGX30min] were assessed and normalised to MEGX test results after 1 mg kg(-1) lignocaine. On days 7 and 14 the lignocaine and MEGX plasma concentrations were measured over a 300 min period. MEGX test results and lignocaine and MEGX plasma pharmacokinetics before and after induction with rifampicin were compared.

RESULTS

The lignocaine plasma clearance increased from 7.5+/-1.2 ml min(-1) kg(-1) before to 8.6+/-2ml min(-1) kg(-1) (P=0.026) after induction. The normalised MEGX30min concentrations increased from 61+/-14 (day 7) to 82+/-34 microg l(-1) (day 14) by a mean of 21 microg l(-1) (95% confidence interval: -3 to 44 microg l(-1)) (P=0.055).

CONCLUSION

An insignificant increase of MEGX plasma concentrations was found in 10 volunteers after induction of CYP3A4 activity by rifampicin. Therefore, the MEGX test is not a sensitive marker of P-450 induction in healthy human liver.

Lidocaine and benzalkonium analysis and titration in drugs using new ISFET devices

Two new ISFETs recently developed by us have now been applied to some pharmaceutical determinations in real matrices; the first device, responsive to cationic surfactants, was employed in the determination of benzalkonium chloride contained in two different disinfectant solutions and in three types of commercial collyrium; the second device, responsive to cocaine hydrochloride, showed an appreciable response also to lidocaine hydrochloride and was used in the determination of lidocaine hydrochloride contained in some injectable antibiotics. The repeatability and accuracy of measurements performed in the analysis of these pharmaceutical matrices using new solid state sensors were evaluated. A further aspect of the research involved the use of two sensors to record complete titration curves for the determination of benzalkonium chloride, cocaine hydrochloride and lidocaine hydrochloride, respectively. Applications to real matrices were also performed by analysing by titration pharmaceutical formulations containing benzalkonium chloride, or lidocaine hydrochloride and an illicit powder containing cocaine hydrochloride and sugars.

Adulterants encountered in the illicit cocaine market

Illicit cocaine samples (156), seized on Rome's illegal market between January 1996 and June 1997, were examined. Both the purity of the cocaine and the presence of substances employed for dilution were determined for each sample. Adulterants were found in many of the street samples analysed. Lidocaine (average 14.7%) followed by caffeine (average 9%) proved to be the adulterants most frequently encountered in the cocaine samples.

Evaluation of the function of primary human hepatocytes co-cultured with the human hepatic stellate cell (HSC) line LI90

Most bioartificial liver devices utilise primary hepatocytes alone although some have considered the use of non parenchymal cells in addition. However the effects of co-culture of human hepatocytes with different sinusoidal cell types has not been fully investigated. In this study we have examined the influence of co-culturing primary human hepatocytes with the human hepatic stellate cell (HSC) line, LI90. Cultures were monitored by light microscopy and on days 4, 8 and 14 urea synthesis and cytochrome P450 activity were measured. Morphologically LI90 cells proliferated to fill spaces between and into adjacent islands of hepatocytes. On day 14 cytochrome P450 activity in co-culture was significantly improved compared to hepatocytes cultured alone. By contrast, urea synthesis in hepatocytes was unaffected by single or co-culture. Therefore it can be concluded that a combination of primary human hepatocytes with LI90 cells is beneficial for growth and some stability of hepatocytes and may therefore be appropriate for seeding bioartificial liver devices.

Monoethylglycinexylidide (MEGX) test in patients with different liver diseases

We have studied the levels of the MEGX test in a heterogeneous group of 50 patients with chronic liver disease and with hepatic tumours and we have compared it with the routine LFTS commonly used to assess liver function and with the Child-Pugh Classification system. Our results demonstrate a statistically significant relationship between MEGX levels and prothrombin levels, and between MEGX and alkaline phosphatase and a highly significant relationship between MEGX and cholinesterase. In the group of patients with cirrhosis we found a statistically significant difference amongst the MEGX levels in the 3 classes of the Child Classification system. The MEGX test is a good index in evaluating hepatic function and it is also quick and easy to perform and capable of determining residual liver function. The test can also be used for preoperative assessment in patients with focal hepatic lesions, especially in those with a previous history of cirrhosis, and in patients with functional hepatic disease.

[The detection and quantitative determination of lidocaine and novocainamide in biological fluids]

Offers methods for isolation of lidocaine and novocainamide present together in the urine, blood plasma, and saliva. Demonstrates the possibility of identifying these substances in biological fluids by thin-layer and gas liquid chromatography. Proposes methods for measuring lidocaine and novocainamide in biological objects by UV spectrometry (combined polynomial) and gas liquid chromatography. Demonstrates the reliability of the results.

Case report of an unusual use of lidocaine during episodes of self mutilation

We are reporting on a case of polyintoxication by cocaine, lidocaine, methadone, and dextromoramide. This conclusion is supported by the analysis of a strand of hair. We note for the first time the detection of dextromoramide as well as lidocaine and desethyl-lidocaine in hair. Concentrations in hair were: cocaine = 2.4 ng/mg, benzoylecgonine = 0.3 ng/mg, methadone = 10.2 ng/mg, EDDP = 1.5 ng/mg, dextromoramide = 1.6 ng/mg, lidocaine = 115.9 ng/mg and desethyl-lidocaine = 1.6 ng/mg. The victim who was seeking an anesthesia effect without the loss of consciousness ingested cocktails during episodes of self mutilation. The wounds were of two different types and with different morphological locations: long and deep without ablation of tissue, clean lacerations found on the neck, the pectoral region, and the left upper extremity; either round or discoid with deep excavation found on the head (ears, forehead, chin, and lips) and also, on the neck and on the left upper extremity. Near the most recent wounds, needle marks were noticed indicating probable local infiltration of lidocaine.

[The differential diagnosis of fatal outcomes in patient treatment with lidocaine]

A method for isolation, identification, and measurement of lidocaine is proposed for investigations of biological specimens. The presence of lidocaine is confirmed by common alkaloid reactions, chromatography in a thin layer of adsorbent, and color test. Lidocaine concentration is measured by extraction photoelectrocolorimetry. A formula is proposed, permitting a tentative assessment of the injected lidocaine dose. The threshold identification value is 0.2 mg%, threshold detection value 0.5 mg%.