Metabolism of docetaxel by human cytochromes P450: interactions with paclitaxel and other antineoplastic drugs.

The metabolism of docetaxel by human liver microsomes was investigated in vitro and compared with that of paclitaxel. A main docetaxel metabolite was generated by human liver microsomes in the presence of NADPH: retention time in high pressure liquid chromatography and its ion fragmentation in mass spectrometry were identical to those of the authentic derivative hydroxylated at the butyl group of the C13 side chain. Kinetic measurements and chemical and immunological inhibitions demonstrated that CYP3A was implicated in the hydroxylation of docetaxel: Km (2 microM) and Vm values of docetaxel for human liver microsomes were comparable to those calculated for the formation of metabolite p-hydroxy-phenyl C3' paclitaxel (M4). Docetaxel hydroxylation correlated only with the CYP3A content of microsomes and with CYP3A-dependent 6 beta-hydroxylation of testosterone and 16-hydroxylation of dehydroepiandrosterone. The formation of hydroxydocetaxel was strongly reduced by CYP3A inhibitors such as ketoconazole, midazolam, erythromycin, testosterone, orphenadrine, and troleandomycin, whereas quinidine (CYP2D6), hexobarbital, tolbutamide, and mephenytoin (CYP2C) had no or little effect. The hydroxylation of docetaxel exhibited a highly positive correlation with the formation of metabolite M4 of paclitaxel (r = 0.929, P < 0.0001, n = 12), but not with its 6-hydroxylation (r = 0.48, P > 0.15). Docetaxel abolished the hydroxylation of paclitaxel metabolite M4, but was totally inactive on its 6 alpha-hydroxylation. Conversely, paclitaxel reduced significantly the hydroxylation of docetaxel. We examined in vitro the possible interaction among docetaxel, paclitaxel, and drugs which could be associated during chemotherapy. Cisplatin, verapamil, doxorubicin, vinblastine, and vincristine at concentrations usually recommended did not markedly modify taxoid metabolism. Ranitidine and diphenylhydramine had no effect, but 100 microM cimetidine partially inhibited the formation of 6 alpha-hydroxypaclitaxel. Pretreatment of patients with barbiturates strikingly stimulated docetaxel hydroxylation, whereas no acceleration of docetaxel hydroxylation was noticed in a patient receiving steroids.

IgA glomerulonephritis associated with microscopic polyangiitis or Churg-Strauss syndrome.

When renal insufficiency occurs in classical antineutrophil cytoplasm antibody- (ANCA) associated vasculitides, histological examination usually finds pauci-immune focal segmental glomerulonephritis. We report on 2 cases of histologically proven necrotizing vasculitis associated with IgA nephropathy. Concomitant vasculitis and IgA nephropathy has only rarely been reported but this joint occurrence may not be coincidental as its pathophysiology is not known. Among vasculitides, IgA nephropathy has more frequently been associated with Henoch-Schoenlein purpura: one microscopic polyangiitis unusual because the patient simultaneously presented ANCA and microaneurysms, and the other Churg-Strauss syndrome associated with mild renal insufficiency. This uncommon association might represent a possible overlap syndrome between these ANCA-associated vasculitides and IgA nephropathy or simply a new type of glomerulonephritis that must be taken into account in these vasculitides.

Biotransformation of taxoids by human cytochromes P450: structure-activity relationship.

The metabolism of paclitaxel and docetaxel by human liver microsomes was investigated in vitro. The main metabolite of paclitaxel formed in vitro was the 6 alpha-hydroxypaclitaxel: its formation largely exceeded the formation of other metabolites hydroxylated on the lateral chain by rat liver microsomes and initially characterized in rat bile. In contrast, in vitro studied showed that the initial metabolite of docetaxel resulted from the hydroxylation of the tert-butyl of the lateral chain at C13 and that the same metabolites were formed in human and animal models. Comparison of individual CYP protein content of human microsomes and catalytic activities with taxoid biotransformation, showed that 2 distinct isoforms were assigned to the 6 alpha-hydroxylation (CYP2C) and to the hydroxylation of the lateral chain (CYP3A4). Chemical and immunological inhibitions confirmed these assumptions. The effect of antineoplastic drugs potentially associated with taxoids during chemotherapy has been tested in vitro on paclitaxel and docetaxel biotransformations. In the therapeutic range, vincristine, vinblastine, doxorubicine and cisplatin elicited a moderate or no inhibition of paclitaxel and docetaxel metabolism, as well as cimetidine, ranitidine and diphenylhydramine used to prevent major side effects associated with taxoid therapy. In patients given barbiturates, the hydroxylation on the lateral chain of paclitaxel and docetaxel was markedly stimulated and resulted from the induction of CYP3A isoforms. These results clearly demonstrated that the biotransformation of paclitaxel and docetaxel by human liver microsomes was supported by 2 distinct CYP proteins and that drug interactions could modify the therapeutic efficiency of taxoids during chemotherapy.

[Sensory neuropathy of the trigeminal nerve and scleroderma]. / Neuropathie sensitive du nerf trijumeau et sclérodermie.

Sensory neuropathy of trigeminal nerve is one of the neurological complications of systemic diseases, particularly scleroderma. Three cases are reported in which onset occurred at different stages of the disease, the main symptom being painful dysesthesias. All three branches of the trigeminal nerve may be affected but a preference is apparent for V2 and V3. Signs are usually limited to hypoesthesia and the chronic course is influenced little by treatment.

[Periarteritis nodosa related to hepatitis B virus. Determination of a new therapeutic strategy: 13 cases]. / Périartérite noueuse liée au virus de l'hépatite B. Détermination d'une stratégie thérapeutique nouvelle: 13 observations.

The treatment and prognosis of periarteritis nodosa associated with hepatitis B virus were reconsidered from a series of 13 patients representing 32.5 per cent of the 40 patients with periarteritis nodosa admitted during the same period. HBs and HBe antigens were present in every case, and hepatitis B virus replication was demonstrated by the finding of viral DNA in serum. One patient had anti-HBc IgM's. Five patients were treated with corticosteroids, cyclophosphamide and occasional plasma exchanges. All were cured or achieved complete remission. Eight patients were treated with plasma exchanges and vidarabine, either as first-line therapy (3 cases) or after failure of corticosteroids and/or immunosuppressants (5 cases). This treatment was clinically effective in 5/8 cases, including 3 with seroconversion. The 2 patients in whom the combined treatment failed were given corticosteroids; one of them also had plasma exchanges. The 8th patient died after a few days of treatment. Eleven of the 13 patients are still alive and either cured or in complete remission. Two patients who developed severe chronic hepatitis after steroids were discontinued received vidarabine alone: arrest of viral replication was obtained in both cases, with emergence of an anti-HBe (but not anti-HBs) antibody. The overall positive virological response rate to vidarabine alone or combined with plasma exchanges was 50 per cent. When vidarabine was prescribed as treatment of acute periarteritis nodosa (the 2 cases where it was used for chronic hepatitis being excluded), this response rate was 37.5 per cent. This, in patients with periarteritis nodosa associated with hepatitis B virus immunosuppressive drugs should be withdrawn and replaced by plasma exchanges and antiviral agents. This would be the first-line treatment to be replaced by corticosteroid therapy if it fails.

Paclitaxel metabolites in human plasma and urine: identification of 6 alpha-hydroxytaxol, 7-epitaxol and taxol hydrolysis products using liquid chromatography/atmospheric-pressure chemical ionization mass spectrometry.

Reversed-phase high-performance liquid chromatography/mass spectrometry (LC/MS), with an atmospheric-pressure chemical ionization (APCI) interface, has been applied to the identification of metabolites and derivatives of paclitaxel (taxol) in plasma and urine of patients treated with this new anticancer drug. Protonated molecules with substantial fragmentation were obtained using this ionization technique. The three ion series observed are characteristic of the intact molecule, the taxane ring, and the side chain at C13. Their analysis gives information about chemical modifications of the taxane structure at different positions of the molecule. Urine and plasma extracts were evaluated using the capacity to perform MS analysis directly on the entire effluent from conventional LC columns. Excellent spectra were obtained with 50 pmol of separated compounds in full scan mode. This technique allowed highly sensitive identification of 6 alpha-hydroxytaxol, the major human biliary metabolite, and of 7-epitaxol in extracts of plasma and urine from patients. Taxol hydrolysis derivatives were observed for the first time in urine 24 hours after the end of the infusion period. Sensitivity could be increased further using single ion monitoring (SIM) mode, once a target derivative was identified. These results demonstrate that LC/MS with an APCI interface is useful for the characterization and pharmacokinetic analysis of taxoids in biological matrices.

Gastrointestinal tract involvement in polyarteritis nodosa and Churg-Strauss syndrome.

OBJECTIVE: To study the nature and incidence of gastrointestinal (GI) manifestations in polyarteritis nodosa (PAN) and Churg-Strauss syndrome (CSS) and define their therapeutic and prognostic implications. METHODS: Fifty-three patients (29 males, 24 females) affected with PAN or CSS and followed in our institution were included in a retrospective study. Patients were divided into 2 groups: patients without GI manifestations (group A) and patients with GI manifestations (group B). Among patients with GI manifestations we have studied a subgroup with a possibly poorer prognosis in whom the following symptoms were present: GI tract hemorrhage, intestinal perforation, digestive tract surgery due to PAN manifestations, intractable abdominal pain and weight loss greater than 20% of normal weight due to GI tract ischemia. RESULTS: The clinical manifestations were those that are classically encountered in PAN and CSS. Every patient fulfilled the American College of Rheumatology (ACR) criteria for PAN and CSS. Thirty-five patients without GI manifestations were included in group A and 18 patients (34%) with GI manifestations in group B. The mean age of the group at the time of diagnosis was 56.9 +/- 19.1 years (range: 21-71 years) in group A and 47.5 +/- 16.8 years (range: 12-82) in group B. GI manifestations were considered as one of the symptoms revealing PAN in 7 (13.2%) cases. Six of the 18 patients with GI manifestations had definite organ involvement related to vasculitis. Abdominal pain without characteristic organ involvement or surgical emergency was present in 12/18 patients. HBV infection was more frequently observed in group B than in group A. Survival curves showed that at 10 years, 80% of the patients in group A were alive versus 67% in group B (P not significant). For the 9 patients with severe GI manifestations, the survival curves showed that, at 10 years, 44% of them were alive versus 80% in the other group A (p < 0.001). CONCLUSIONS: GI manifestations are frequent in PAN and CSS and were present in 34% of our patients. Prognosis of PAN with GI manifestations is not statistically different than in PAN without GI involvement, except for patients with severe digestive complications.

[Treatment of systemic diseases with pulse cyclophosphamide: 15 cases]. / Traitement des maladies systémiques par bolus de cyclophosphamide. Quinze observations.

Fifteen patients suffering from severe systemic diseases were treated with monthly pulses administration of cyclophosphamide (0.7 g/m2 of body surface): 8 acute systemic lupus erythematosus, 2 Wegener's granulomatous, 1 polyarteritis nodosa, 1 rheumatoid vasculitis, 1 progressive systemic sclerosis, 1 relapsing uveitis and 1 dermatopolymyositis. The indications for cyclophosphamide were: glomerulonephritis (6 cases), resistance to previous treatments (7 cases) and undesirable side effects of corticosteroid therapy (2 cases). After 3 pulses, the disease was controlled in 12 patients (80%) and corticosteroids could be decreased in all 12 cases without an evolutive relapse of the disease. Five patients developed infections (2 septicemia, 1 zona, 1 herpes gingival stomatitis and 1 viral meningitis) which were treated without sequelae. One patient developed cystitis with hematuria after the 3rd pulse; association of mesna, a urinary tract protective agent, enabled the continuation of treatment without a cystitis relapse. At the end of our retrospective study, the efficacy of pulse cyclophosphamide administration seems to be satisfactory but the risk of undesirable side effects should limit its use to severe systemic diseases or those resistant to conventional therapies.

Contextual effects on word production: a lifespan study.

The effect of sentence priming on picture naming was investigated across the lifespan, from age 3 to 87 years. Names that are normally acquired before 3 years of age were presented in auditory contexts that were semantically congruent, incongruent, or neutral in relation to each picture and its name. Sentential priming was present at all age levels. Facilitation (neutral vs. congruent) was significantly by 4 years of age and did not vary significantly with age. Interference (incongruent vs. neutral) was significant at all age levels, but changed nonmonotonically with age (largest in the youngest children, stable from young adulthood through age 70, with a small increase in the oldest participants). We conclude that picture naming is a useful tool for the investigation of sentential priming effects across the lifespan and that it can reveal potentially interesting developmental changes in the effects of sentential context on word retrieval.

[Common variable immunodeficiency: one or multiple illnesses? 3 clinical cases]. / Déficit immunitaire commun variable: une ou plusieurs maladies? Trois observations cliniques.

Common variable immunodeficiency (CVID) is a major antibody-deficiency syndrome, associated with increased risk of bacterial infection, as well as autoimmune and granulomatous disease. The clinical and immunological features are heterogeneous. This heterogeneity is expressed by the case reports of three selected patients. These observations will be discussed, with reference to a recent classification of CVID distinguishing four different clinical entities: i) CVID presenting with clinical and immunological features of X-linked agammaglobulinemia; ii) CVID presenting with clinical and immunological features of X-linked hyper-IgM syndrome; iii) CVID associated with systemic granulomatous disease; and iiii) CVID associated with autoimmune manifestations.

New application of myocardial antimyosin scintigraphy: diagnosis of myocardial disease in polymyositis.

Heart disease is a rare but important complication of polymyositis. Diagnosis of myocardial disease is usually based on non-specific clinical, electrocardiographic, and echocardiographic data. This paper reports a case of polymyositis with myocardial disease diagnosed by myocardial imaging with radiolabelled antibody to myosin, a specific marker of the necrotic myocardial fibre.

Modification of paclitaxel metabolism in a cancer patient by induction of cytochrome P450 3A4.

Biliary, plasma, and urinary disposition of paclitaxel and paclitaxel metabolites were determined simultaneously in a patient with percutaneous biliary drain. The complete chemical structures of the major metabolites were established by mass spectrometry and NMR spectroscopy. A nonlinear elimination model was indicated by the fact that the rate of biliary excretion of paclitaxel rose as plasma concentrations fell. Dihydroxypaclitaxel was the predominant biliary metabolite, in contrast to the barely detectable levels in two previous patients. This derivative results from hydroxylation at the C6 position of the taxane ring and at the phenyl C3'-position on the C13 side chain mediated by cytochrome P450 2C8 and 3A4, respectively. In line with this mechanism, the two other main metabolites corresponded to 6alpha-hydroxypaclitaxel and to the paclitaxel derivative hydroxylated in the para-position on the phenyl ring at the C3'-position of the C13. A high CYP3A4 activity in the patient is consistent with the repeated administration of methylprednisolone for 14 days before paclitaxel treatment, a compound known to induce the CYP3A isoform, and with the increased ratio of 6beta-hydroxycortisol/cortisol in urine, an index of CYP3A activity. These findings emphasize the influence of pretreatment with corticoids on the disposition of paclitaxel.

Giant cell arteritis of the female genital tract with temporal arteritis.

The clinical and pathological features of a patient with giant cell arteritis of the uterus and ovaries are described. A 61 year old woman had fever and weight loss over a period of eight months. A hysterectomy with bilateral salpingo-oophorectomy was performed for a large cystic ovarian mass. Histological examination showed a benign ovarian cyst and unexpected giant cell arteritis affecting numerous small to medium sized arteries in the ovaries and myometrium. The diagnosis of temporal arteritis was confirmed by a random temporal artery biopsy, despite the absence of symptoms of temporal arteritis. This observation is compared with previously reported cases and the relation between granulomatous arteritis of the genital tract and temporal arteritis is discussed. The main differential diagnosis in this localisation was represented by Wegener's granulomatosis and periarteritis nodosa.