Pravastatin in vivo reduces mononuclear cell migration through endothelial monolayers

The objective was to evaluate pravastatin modulation on peripheral blood mononuclear cell (PBMC) migration across endothelial monolayers. Eleven hypercholesterolaemic patients were treated with pravastatin 20 mg/day. At baseline (T0), after 40 days (T40) and after 6 months (T 6 months) of treatment total serum cholesterol, low-density lipoprotein (LDL), high-density lipoprotein, triglycerides, C-reactive protein, as well as tumour necrosis factor-alpha (TNF-alpha) and metalloproteinases-9 plasma levels were evaluated. At the same time points the effect of pravastatin on migration of PBMCs through a monolayer of murine brain endothelial cells was studied both in basal conditions and after endothelial stimulation with recombinant mouse TNF-alpha 10 ng/ml for 24 h. Seven volunteers were used as healthy controls. Significant decreases in total cholesterol, LDL and triglycerides as well as inhibition of transmigration were observed. PBMCs transmigration in patients prior to pravastatin therapy was higher than in healthy controls. These results suggest that pravastatin could be of benefit in a spectrum of diseases characterised by extravasation of PBMCs into the central nervous system.

Expression of Drug Resistance Proteins Pgp, MRP1, MRP3, MRP5 AND GST-π in Human Glioma

Chemotherapy in glioma is poorly effective: the blood-brain barrier and intrinsic and/or acquired drug resistance of tumor cells could partly explain this lack of major effect. We investigated expression of P-glycoprotein (Pgp), multidrug resistance protein (MRP) 1, MRP3, MRP5 and glutathione-S-transferase pi (GST-pi) in malignant glioma patients. Cytofluorimetric analysis of 48 glioma specimens and 21 primary cultures showed high levels of MRP1, moderate levels of MRP5 and low levels of Pgp, GST-pi and MRP3. Immunohistochemistry (25 glioma specimens) showed expression of GST-pi (66.7% of cases), MRP1 (51.3%), MRP5 (45.8%), Pgp (34.8%) and MRP3 (29.9%) in tumor cells. Moreover, analysis of tumor samples by real time quantitative PCR showed mRNA expression of all investigated genes. Tumor vasculature, analyzed in glioma specimens and in tumor derived endothelial cells, showed expression of all investigated proteins. Non-tumor brain samples (from a patient with arteriovenous malformation and from one with epilepsy), normal human astrocytes and cultured endothelial cells were also analyzed: astrocytes and endothelial cells expressed the highest levels of the investigated proteins, mainly MRP1 and MRP5. No significant differences in proteins expression were detected between primary or recurrent gliomas, suggesting that glioma chemoresistance is mostly intrinsic. Therefore, we detected, for the first time, the presence of MRP3 and MRP5 on glioma specimens--both in tumor and endothelial cells--and we delineated an expression profile of chemoresistance proteins in glioma. The possible association of inhibitors of drug efflux pumps with chemotherapy could be investigated to improve drugs delivery into the tumor and their cytotoxic effects.

Immunotherapy with bovine aortic endothelial cells in subcutaneous and intracerebral glioma models in rats: effects on survival time, tumor growth, and tumor neovascularization

High-grade gliomas are aggressive tumors of the central nervous system characterized by endothelial cell proliferation and a high degree of vascularity. Conventional antitumoral treatments (i.e., surgery, radiotherapy, and chemotherapy) do not achieve satisfactory results (median survival in glioblastoma 12-18 months). It has been suggested that immunotherapy with xenogenic endothelial cells could slow tumor growth rate in a number of tumors in a murine model, but the study did not include gliomas. In experiments performed in our laboratory, vaccination with proliferating bovine aortic endothelium increased survival time in Fischer rats inoculated intracerebrally with 9L. Immunotherapy was also able to reduce the growth of subcutaneously injected 9L gliosarcoma cells in Fischer rats and to decrease microvessel density within the tumors, in the absence of major organ toxicity. Immunoglobulins (Ig) in the sera from vaccinated rats stained bovine aortic endothelium as well as human umbilical vein endothelium in active proliferation. Moreover, immune sera from immunized rats stained microvessels of human malignant glioma specimens and vessels of intracerebrally implanted tumors. Two proteins of MW of 11 and 19 kDa were identified by Western blot as targets of Ig elicited by vaccination. A possible future development is to select peptides/proteins suitable for vaccination in humans, avoiding the biohazards connected with xenogenic whole-cell vaccination.

Effects of thalidomide on parameters involved in angiogenesis: an in vitro study

In an attempt to elucidate the mechanism(s) of action of thalidomide, a reportedly antiangiogenic molecule recently tested in the treatment of relapsing malignant gliomas, we performed an in vitro study on the following parameters: (a) effect of thalidomide on proliferation of endothelial cells; (b) effect of thalidomide on expression of alpha(v)beta3 integrin on the surface of endothelial cells; (c) effect of thalidomide on the release by endothelial cells of MMP-2, IL-8 and TNF-alpha. The results show that thalidomide inhibits endotelial cell proliferation induced by bFGF and VEGF, more so if the cells are grown on vitronectin; moreover, treatment with thalidomide reduces the release of MMP-2 and IL-8 by endothelial cells, suggesting a further pathway for the antiangiogenic activity of drug. On the other hand, thalidomide does not modify expression of alpha(v)beta3 on endothelial cells.

Dystrophic phenotype of canine X-linked muscular dystrophy is mitigated by adenovirus-mediated utrophin gene transfer

Utrophin is highly homologous and structurally similar to dystrophin, and in gene delivery experiments in mdx mice was able to functionally replace dystrophin. We performed mini-utrophin gene transfer in Golden Retriever dogs with canine muscular dystrophy (CXMD). Unlike the mouse model, the clinicopathological phenotype of CXMD is similar to that of Duchenne muscular dystrophy (DMD). We injected an adenoviral vector expressing a synthetic utrophin into tibialis anterior muscles of newborn dogs affected with CXMD and examined transgene expression by RNA and protein analysis at 10, 30 and 60 days postinjection in cyclosporin-treated and -untreated animals. Immunosuppression by cyclosporin was required to mitigate the immune response to viral and transgene antigens. RT-PCR analysis showed the presence of the exogenous transcript in the muscle of cyclosporin-treated and -untreated animals. The transgenic utrophin was efficiently expressed at the extrajunctional membrane in immunosuppressed dogs and this expression was stable for at least 60 days. We found reduced fibrosis and increased expression of dystrophin-associated proteins (DAPs) in association with muscle areas expressing the utrophin minigene, indicating that mini-utrophin can functionally compensate for lack of dystrophin in injected muscles. For this reason, utrophin transfer to dystrophin-deficient muscle appears as a promising therapeutic approach to DMD.

New high-performance liquid chromatographic method for plasma/serum analysis of lamotrigine

Lamotrigine is an anticonvulsant drug recently approved in Italy for clinical use. Therapeutic monitoring of lamotrigine is relevant for patient management and avoidance of toxicity. The authors describe a simple, sensitive, and highly selective high-performance liquid chromatography method that does not involved extraction for analysis of serum lamotrigine. Serum (20 microL) with internal standard (BW 725 C) was injected directly into a column (25 cm x 4.6 mm) with an internal surface reversed phase (ISRP). The mobile phase consisted of 0.01 mol/L potassium phosphate bibasic (pH 6.0) and acetonitrile (82:18), the flow rate was 1.0 mL/min, and UV detection was optimized at 330 nm. The overall between-run coefficient of variance ranged from 1.89% to 3.25% and the lowest limit of detection was 0.05 mg/L. High linearity (r = 0.9996) in a wide range of concentrations (0.1-20.0 mg/L) and no interference with other antiepileptic drugs, benzodiazepines, and tricyclic antidepressants were the other characteristics of the method. The innovation of this method is the use of ISRP column and the choice of detection wavelength, which allow a shorter analysis time (5-6 minutes). The possibility of direct injection of plasma samples into the column permits a reduction in reagent consumption and in analytic steps, and hence in analytic error.

Single-Dose Pharmacokinetics of Lamotrigine in Children: Influence of Age and Antiepileptic Comedication

To evaluate the influence of pediatric age and antiepileptic comedication on the single-dose pharmacokinetics of lamotrigine, 19 patients with epilepsy (10 comedicated with enzyme inducers and 9 comedicated with valproic acid) aged 8 months to 30 years received a single oral dose of lamotrigine (0.6 to 2.2 mg/kg) after an overnight fast. Blood samples were collected for at least 36 hours and plasma lamotrigine concentrations were determined by high-performance liquid chromatography. Pharmacokinetic parameters were calculated by noncompartmental analysis. Lamotrigine half-life (T1/2) and oral clearance (Cl/F) values were significantly lower and significantly higher, respectively, in patients comedicated with enzyme inducers than in those receiving valproic acid (T1/2 = 8.1 vs. 41.7 hours respectively, P < 0.001; Cl/F = 0.11 vs. 0.04 L/h per kg respectively, P < 0.005, geometric means), whereas Cmax and Tmax values were comparable in the two groups. The differences in pharmacokinetic parameters persisted when comparisons were made within subgroups stratified according to age. Within groups of patients homogeneous for type of comedication, Cmax and AUC values tended to be lower in children aged less than 12 years than in older patients. There was no significant relationship between half-life values and age. The authors conclude that both age and type of comedication influence lamotrigine pharmacokinetics. The reduction in lamotrigine concentrations caused by enzyme inducers and the elevation caused by valproic acid can be explained by stimulation and inhibition, respectively, of lamotrigine glucuronidation. On the other hand, the lower plasma lamotrigine levels in children than in adolescents and older patients may not be explainable solely by differences in metabolic rate.

The serotonergic agent m-chlorophenylpiperazine induces migraine attacks: A controlled study

In a double-blind study versus placebo, the serotonergic agent m-chlorophenylpiperazine (mCPP) was administered to 20 healthy control subjects and 19 migraineurs to investigate the ability of mCPP (0.5 mg/kg) to induce typical migraine attacks. In the following 24 hours there were more migraines after mCPP than after placebo in both groups. These findings are consistent with involvement of 5HT2B,2C,1A receptor subtypes in the pathophysiology of migraine.

Intrauterine growth in the offspring of epileptic women: a prospective multicenter study

The aim of the present study was to evaluate the risk of intrauterine growth delay in the offspring of epileptic mothers and to quantify the risks of intrauterine exposure to antiepileptic drugs (AEDs). Data concerning 870 newborns, prospectively collected in Canada, Japan and Italy, using the same study design, were pooled and analyzed. The overall proportion of newborns whose body weight (7.8%) or head circumference (11.1%) at birth were below the 10th percentile was not increased. However, logistic regression analysis showed that the risk of small head circumference was significantly higher in Italian than in Japanese (RR 4.2; 95% CI: 2.2-8.0) or Canadian children (RR 2.6; 95% CI: 1.1-6.5), and in children exposed to polytherapy (RR 2.7; 95% CI: 1.2-6.3), phenobarbital (PB) (RR 3.6; 95% CI: 1.4-9.4) and primidone (PRM) (RR 4.5; 95% CI: 1.5-13.8). Country was also the only factor affecting low body weight, with Italian children having a higher risk than Japanese (RR 5.2; 95% CI: 2.6-10.4) or Canadian (RR 8.8; 95% CI: 2.0-38.1) children. Due to the small categories, the influence of AED doses and plasma concentrations was studied for each individual AED, without adjustment for the other potential confounding factors. A clear dose-dependent effect was found for PB and PRM in terms of both small head circumference and low body weight, and a concentration-dependent effect for PB in terms of small head circumferences. The size of the difference between the Italian and the other two populations, which is only partially explained by differences in therapeutic regimens, suggests that genetic, environmental and ethnic factors also need to be taken into account when considering possible explanations.

5-HT1A receptor hypersensitivity in migraine is suggested by the m-chlorophenylpiperazine test

Involvement of the cerebral serotoninergic system has been invoked to explain the origin of the pain and the vascular phenomena in migraine. To further investigate the type of cerebral serotonin receptors that may be altered in migraine, the prolactin (PRL) and cortisol responses to m-chlorophenylpiperazine (mCPP), a selective 5-HT1A,-5-HT(2A/C) receptor agonist, were monitored in 12 patients suffering from migraine without aura and in 14 matched healthy controls. Each subject underwent two challenges, one with mCPP (0.5 mg/kg) and the other with placebo (orally) using a double-blind crossover design. Anxiety level was measured by the State Trait Anxiety Inventory. Migraine patients had a greater PRL response to mCPP (p = 0.05) and greater anxiety (p < 0.01) than controls; cortisol response to mCPP did not differ suggesting that 5-HT2C receptors are normal in migraine. Augmented PRL response to mCPP could derive from 5-HT1A receptor hypersensitivity, perhaps as as a consequence of anxiety due to pain expectation. Cerebral 5-HT1A hypersensitivity could also explain the increased occurrence of migraine attacks during anxiety.

Lamotrigine plasma concentrations in children and adults: influence of age and associated therapy

The effects of age and concomitant treatment on plasma lamotrigine (LTG) concentration/dose (C/D) ratios were retrospectively evaluated on 482 consecutive routine LTG determinations from 106 chronically-treated patients with epilepsy (40 children and adolescents aged younger than 16 years, and 66 adults aged 17 to 62 years). A linear dose/level relationship was observed in individual patients but not in the cumulative analysis, which failed to show any correlation between the administered LTG dose and plasma concentrations. In the adult group, there were no correlations between the administered LTG dose and plasma concentrations. Associated antiepileptic therapy affected the LTG concentration/dose ratio, which was significantly higher in the patients receiving valproic acid (3.4 +/- 2.0, n = 23) and significantly lower in those treated with enzyme-inducing antiepileptic drugs (0.6 +/- 0.5, n = 57) than in the patients receiving valproic acid in combination with enzyme-inducing antiepileptic drugs, ethosuximide, vigabatrin, or clobazam (1.9 +/- 1.6, n = 26). The LTG C/D ratios significantly increased with increasing plasma valproic acid concentrations, and significantly decreased with increasing phenytoin concentrations. The effect of enzyme-inducing antiepileptic drugs increased with the number of associated drugs. A clear age effect was demonstrated in the homogeneously treated subgroups, in all of which adults had higher C/D ratios than children.

The m-chlorophenylpiperazine test in cluster headache: a study on central serotoninergic activity

The central serotoninergic agonist m-chlorophenylpiperazine (m-CPP) stimulates several 5HT receptor subtypes. It induces the release of both cortisol and prolactin (PRL). In this study we investigated central serotoninergic responsiveness in cluster headache by monitoring cortisol and PRL responses to m-CPP administration. Twenty-three patients with episodic cluster headache and 17 sex-matched and age-matched healthy subjects were studied. The cluster headache patients were tested during a cluster period, and none were receiving prophylaxis. A single oral dose of m-CPP, 0.5 mg/kg, was given at time 0. Blood samples were drawn at -30, 0, 30, 60, 90, 120, 150 and 180 min. PRL and cortisol levels were assayed in the samples. PRL and cortisol delta maxima (delta maximum = maximum response - baseline level at time 0/baseline level at time 0) were evaluated in each patient and mean values compared. Serum levels of m-CPP were detected by HPLC and correlated to hormonal responses. Reduced cortisol (p < 0.02) and increased PRL (p < 0.05) delta maxima were observed in cluster headache patients. Increased basal cortisol plasma levels (p < 0.05) and reduced basal PRL plasma levels (p = 0.06) also characterized cluster headache patients. This is the first study evaluating central serotoninergic responsiveness to m-CPP in cluster headache and these data suggest impaired central serotoninergic function in this pathology.

Primary antiphospholipid syndrome (PAPS) and isolated partial seizures in adolescence. A case report

The case of a young male patient presenting isolated clustered partial seizures is reported. Despite the normality of the neurological features, as well as of ictal and interictal EEG, the MRI (performed three days after the symptoms) disclosed bilateral signal alterations in the parietal cortical region. These abnormalities disappeared at the MRI control examination performed one month later. The finding of positive anticardiolipine antibodies made possible the diagnosis of partial epileptic seizures symptomatic of a vascular disorder ascribed to a Primary antiphospholipid Syndrome (PAPS).

Lamotrigine in resistant childhood epilepsy

Fourteen children (6 M, 8 F) suffering from refractory epilepsy received LTG as add-on therapy. LTG was administered twice daily at dosages increasing up to 2 mg/kg/day (for patients taking VPA) or to 10 mg/kg/day for patients taking AEDs that induce hepatic metabolism. The drug was withdrawn for side effects in 3 cases (rash: two cases, hirsutism: one), because of increased seizure frequency in 2 cases and because of unchanged seizure frequency in one. One patient died from acute respiratory failure, after repeated respiratory tract infections. A decrease in seizure frequency after one year of treatment with LTG was observed in 6 of the 7 patients who completed the study. The median total seizure frequency decreased from 10.7 +/- 7.3 to 3.8 +/- 4.6 seizures per day. At the end of the study, seizure frequency had decreased by more than 50% in 2 patients, by more than 75% in 2 patients, and 2 patients were seizure-free; in the remaining patient seizure frequency was unchanged. The best results were obtained with plasma LTG concentrations ranging from 0.5 to 5.4 micrograms/ml; no further improvement was observed at higher LTG concentrations.

Abnormal amniotic fluid levels of CA 125 in second-trimester Down syndrome pregnancies

The aim of this study was to evaluate the concentration of CA 125 in second trimester amniotic fluid from Down syndrome pregnancies. CA 125 was measured in stored amniotic fluid samples from pregnancies of 14-19 weeks' gestation with and without Down syndrome fetuses. CA 125 levels were expressed in multiples of the median (MOM) for normal pregnancies of the same gestational age. Twenty-one pregnancies with Down syndrome fetuses and 63 unaffected controls matched for maternal age, gestational age, and duration of storage were studied. The median MOM values of the affected pregnancies were significantly higher than those of the controls (1.41 MOM versus 0.99 MOM). These findings show that there is an increased concentration of CA 125 in second-trimester amniotic fluid from Down syndrome pregnancies.

Intrauterine growth in the offspring of epileptic mothers

The present paper concerns the fetal growth of 315 newborns of epileptic mothers prospectively followed from the beginning of pregnancy. In comparison with Italian standards, neonatal weight, length and head circumference at birth were below the 10th percentile in respectively 15.7%, 1.1% and 19.2% of the newborns. Weight at birth was above the 90th percentile in 8 cases. Observed frequencies were significantly higher than expected frequencies for both weight and head circumference. The percentage of newborns with a small head circumference increased significantly according to the number of drugs taken by the mother during the first three months of pregnancy: 7.1% with no drug, 16.8% with one drug, 23.6% with two drugs and 50% with three drugs. A statistically significant correlation was found between gestational age-adjusted head circumference and drug-level scores during the first trimester. Head circumferences below the 10th percentile were fewer among newborns treated with CBZ than among newborns treated with either PB or VPA.

Neoadjuvant chemotherapy in the treatment of recurrent glioblastomas (GBM)

We wondered whether second line chemotherapy in recurrent GBM patients might be useful for debulking the tumor mass and improving patient performance status to prepare the way for second surgical intervention. We have treated 18 recurrent glioma patients with high dose methotrexate (HDMTX) plus 5-fluorouracil (5FU). 5 Patients were responders, 6 had stable disease, and 7 disease progression. 5 patients, 3 PRs and 2 SDs, underwent a second operation after two chemotherapy cycles. Disease progression resumed at 11.5 +/- 7 weeks in the non reoperated patients, and at 32.6 +/- 9.3 weeks in the reoperated group from initiation of neoadjuvant treatment. Survival time in reoperated patients was 82.6 weeks. Although our experience with this policy is still limited, we believe that reoperation in selected recurrent GBM patients can be worthwhile.

Changes in unbound and total valproic acid concentrations after replacement of carbamazepine with oxcarbazepine

Total and free valproic acid (VPA) concentrations were measured in patients switched from a combined VPA and carbamazepine (CBZ) to a combined VPA and oxcarbazepine (OXC) therapy, both administered in individualized daily doses. Four young epileptic patients (13-17 years old) were studied for a 12-week period, total and free VPA concentrations being analyzed just before and 4 h after the morning dose, at the end of VPA and CBZ therapy, and 2 and 10 weeks after CBZ was replaced by OXC. The expected increase in the level/dose (L/D) ratio of total VPA observed at the end of the study was preceded by a clear-cut increase in the L/D ratio of free VPA, which led to VPA-related side effects and required the retitration of VPA daily doses.

Malformations in offspring of 305 epileptic women: a prospective study

This paper deals with malformations detected in 26 of 315 newborns of 305 epileptic mothers followed prospectively. In 3 more cases, malformations were detected in utero and therapeutic abortion was performed. Two hundred and seven women were on monotherapy, 102 on polytherapy and 9 were not treated. In total, malformations overall incidence was 9.1%. Minor anomalies were detected in 42 newborns (13.3%). A higher rate of malformations and minor anomalies was found among offspring of mothers treated with valproic acid (VPA). In the VPA group, mothers of malformed babies had higher plasma levels in the first trimester than mothers of babies without malformations. The need for accurate prenatal diagnostic studies in pregnant women with epilepsy is stressed.

A simple immunoturbidimetric method for IgG and albumin quantitation in cerebrospinal fluid and serum

We describe a simple immunoturbidimetric method for measuring both IgG and albumin in CSF and serum, which enables the calculation of CSF indices. For each protein, only one calibration curve is used for both CSF and serum samples. The assay protocol is simple and similar for both tests. Sensitivity and versatility of the method afford measurements over a very wide range of concentrations (approx. 0.007 to 94 g/l for IgG and 0.06 to 92.40 g/l for albumin). Precision studies (triplicates for 6 runs over 15 days) gave overall CVs: less than or equal to 2.9 and 4.9% for IgG in CSF (11.5 mg/l) and serum (10.28 g/l); less than or equal to 1.3 and 1.1% for albumin in CSF (115 mg/l) and serum (76.89 g/l). Comparison studies showed good correlation with radial immuno-diffusion (r greater than or equal to 0.995 and 0.976 for IgG and albumin) and rate nephelometry (r greater than or equal to 0.967 and 0.982 for IgG and albumin). Thus, the method under investigation proved to be reliable and appears to be particularly suitable for the routine work.

A dry-reagent strip for quantifying carbamazepine evaluated

We examined a new colorimetric homogeneous immunoassay for carbamazepine based on the apoenzyme reactivation immunoassay system (ARIS) principle. The test, in dry-reagent strip format, is to be used with the Ames Seralyzer reflectance photometer. Within-run CVs (n = 20) were 3.0%, 2.7%, and 2.8% at 3.0, 6.1, and 12.1 mg/L; between-run CVs (n = 15, in 15 days) were 4.1%, 2.7%, and 1.9% at 6.0, 9.1, and 12.1 mg/L. Mean analytical recovery was 99.9 (SD 2.3)%. Results by this test (y) for clinical plasma specimens (n = 96) compared very well with those obtained by fluorescence polarization immunoassay (y = 1.01 x - 0.02, r = 0.995) and by liquid chromatography (y = 0.99 x + 0.14, r = 0.990). Bilirubin (45 mg/L), uric acid (145 mg/L), and various anticoagulants at about fourfold the usual concentrations did not interfere. High concentrations of cholesterol (4.9 g/L), triglycerides (3.8 g/L), and hemoglobin (4 g/L) caused slight positive interference. Carbamazepine-10,11-epoxide cross reacted only at greater than or equal to 5 mg/L. The two-point calibration line was validly stored for at least three weeks. Free carbamazepine also can be measured. The test is convenient and rapid (test time 80 s), and thus is particularly useful in all clinical settings where prompt testing is needed.

Quantitative determination of phenobarbital and phenytoin by dry-phase apoenzyme reactivation immunoassay system (ARIS)

We assessed the performance of the apoenzyme reactivation immunoassay system (ARIS) reagent strip tests for determination of phenobarbital (PB) and phenytoin (PHT) with the Seralyzer reflectance photometer. In the assay, the drug of the sample competes with a flavine adenine dinucleotide (FAD)-drug conjugate for binding to a specific antibody; the unbound conjugate then activates apoglucose oxidase to reconstitute glucose oxidase, whose activity is kinetically monitored by a coupled chromogenic reaction. Within-run coefficients of variation (CVs) were less than or equal to 5.0% for PB and less than or equal to 5.6% for PHT; between-run CVs were less than or equal to 6.1% for PB and less than or equal to 6.5% for PHT. Mean analytical recoveries were 100.3% for PB and 100.2% for PHT. Test results were not significantly affected by bilirubin (5 mg/dL), hemoglobin (25 mg/dL), triglycerides (500 mg/dL), uric acid (15 mg/dL), or elevated levels of other antiepileptic drugs. Reagent strip tests correlated very well with substrate-labeled fluorescent immunoassay (r = 0.9923 and 0.9944 for PB and PHT, respectively), enzyme multiplied immunoassay technique (r = 0.9941 and 0.9919), and gas-liquid chromatography (r = 0.9980 and 0.9960). These homogeneous competitive colorimetric immunoassays are particularly suitable for emergency use, for testing small batches of samples, wherever prompt results are needed.

Plasma concentrations of carbamazepine and carbamazepine 10,11-epoxide during pregnancy and after delivery

Plasma concentrations of carbamazepine were monitored in 9 pregnant epileptic patients treated with the drug alone at constant doses during pregnancy and for at least 3 months after delivery. In addition, plasma concentrations of the metabolite, carbamazepine 10,11-epoxide were measured in 6 of the 9 patients. Plasma carbamazepine concentrations were fairly stable during pregnancy, and carbamazepine relative plasma clearances were significantly higher in weeks 4 to 24 than in weeks 25 to 32. After the end of the second trimester, there were no variations in plasma carbamazepine 10,11-epoxide concentrations and carbamazepine 10,11-epoxide:carbamazepine ratios. Both parameters were significantly higher in weeks 4 to 24 than in weeks 25 to 32 of pregnancy.

Changes in primidone/phenobarbitone ratio during pregnancy and the puerperium

Plasma concentrations of primidone and its metabolite phenobarbitone were monitored in 9 pregnant epileptic patients treated with primidone (and in 3 cases other antiepileptic drugs) given at constant doses throughout pregnancy and the puerperium. Phenobarbitone plasma concentrations were monitored in another 6 patients given phenobarbitone itself. A trend towards increasing primidone plasma concentrations during the second quarter of pregnancy was evident in all patients, with a concomitant significant decrease in primidone-derived phenobarbitone plasma concentrations. A trend towards a lowering of plasma concentrations of phenobarbitone administered as such was confirmed. These results suggest the usefulness of a careful monitoring of primidone and primadone-derived phenobarbitone during pregnancy and the puerperium. Discrepancies of findings with primidone and phenobarbitone are discussed in view of the possible mechanism involved.

Plasma levels of primidone and its metabolite phenobarbital: effect of age and associated therapy

The effects of age and associated therapy on plasma primidone (PRM) and derived phenobarbital (PB) concentrations, and on plasma concentrations-to-PRM dose ratios (L/D ratio) were evaluated retrospectively from 408 consecutive PRM and derived PB determinations in 238 chronically treated epileptic patients (153 children and adolescents between 5 months and 15 years of age and 85 adults between 16 and 55 years of age). The correlation between PRM administered and both plasma PRM and derived PB levels was significant; the correlation between PRM and PB plasma levels was also significant, but the scatter of values for the linear regressions was such that the relationship had no predictive value. Significant differences in mean plasma PRM and PB L/D ratios were found between patients aged 0-3 years, 4-9 years, 10-15 years, and adults (16-55 years), with higher values in the older groups. The PB/PRM concentration ratios were significantly lower in children than in adolescents and adults. Concomitant treatment with carbamazepine affected PRM disposition and led to increased L/D ratios for PB and decreased L/D ratios for PRM, whereas phenytoin increased the L/D ratios for PB without any significant change in the L/D ratios for PRM. The variability in the results indicates the need for routine monitoring of PRM and derived PB plasma levels, particularly in pediatric populations, in order to tailor the dose to each patient.