ABCB1 and cytochrome P450 genotypes and phenotypes: influence on methadone plasma levels and response to treatment

BACKGROUND AND OBJECTIVE: The in vivo implication of various cytochrome P450 (CYP) isoforms and of P-glycoprotein on methadone kinetics is unclear. We aimed to thoroughly examine the genetic factors influencing methadone kinetics and response to treatment. METHODS: Genotyping for CYP1A2, CYP2B6, CYP2C9, CYP2C19, CYP2D6, CYP3A4, CYP3A5, ABCB1, and UGT2B7 polymorphisms was performed in 245 patients undergoing methadone maintenance treatment. To assess CYP3A activity, the patients were phenotyped with midazolam. RESULTS: The patients with lower CYP3A activity presented higher steady-state trough (R,S)-methadone plasma levels (4.3, 3.0, and 2.3 ng/mL x mg for low, medium, and high activity, respectively; P = .0002). As previously reported, CYP2B6*6/*6 carriers had significantly higher trough (S)-methadone plasma levels (P = .0001) and a trend toward higher (R)-methadone plasma levels (P = .07). CYP2D6 ultrarapid metabolizers presented lower trough (R,S)-methadone plasma levels compared with the extensive or intermediate metabolizers (2.4 and 3.3 ng/mL x mg, respectively; P = .04), whereas CYP2D6 poor metabolizer status showed no influence. ABCB1 3435TT carriers presented lower trough (R,S)-methadone plasma levels (2.7 and 3.4 ng/mL . mg for 3435TT and 3435CC carriers, respectively; P = .01). The CYP1A2, CYP2C9, CYP2C19, CYP3A5, and UGT2B7 genotypes did not influence methadone plasma levels. Only CYP2B6 displayed a stereoselectivity in its activity. CONCLUSION: In vivo, CYP3A4 and CYP2B6 are the major CYP isoforms involved in methadone metabolism, with CYP2D6 contributing to a minor extent. ABCB1 genetic polymorphisms also contribute slightly to the interindividual variability of methadone kinetics. The genetic polymorphisms of these 4 proteins had no influence on the response to treatment and only a small influence on the dose requirement of methadone.     

CYP2D6 and ABCB1 genetic variability: influence on paroxetine plasma level and therapeutic response

Paroxetine is characterized by large interindividual pharmacokinetic variability and heterogeneous response patterns. The present study investigates plasma concentration and therapeutic response to paroxetine for the influence of age, sex, and CYP2D6 and ABCB1 polymorphisms, the latter gene encoding for the permeability glycoprotein. Genotyping for CYP2D6 (alleles *3, *4, *5, *6, and *xN) and ABCB1 polymorphisms (61A>G, 2677G>T, and 3435C>T) was performed in 71 depressed patients who started 20 mg paroxetine per day and had plasma concentration measured after 2 weeks at a fixed dose. A dose increase to 30 mg per day was possible starting at week 2. For 63 patients, severity of depression (Montgomery-Asberg Depression Rating Scale) was assessed at weeks 0, 2, and 4 and every 2 weeks thereafter until discontinuation. Persistent response was defined as 50% improvement from baseline score sustained from the first occurrence to study end point. Paroxetine concentration significantly differed between female and male patients (median, 28 versus 16 ng/mL; P = 0.001). Differences were not significant between CYP2D6 heterozygous and homozygous extensive metabolizers (median, 27 versus 22 ng/mL; P = 0.074) and between ABCB1 genotypes (P > 0.10). When considered in a multivariate model, CYP2D6 heterozygous extensive metabolizer phenotype (P = 0.062) and female gender (P = 0.001) predicted 1.3-fold and 1.6-fold higher paroxetine concentration, respectively, but fraction of explained variability was modest (21%). Frequency of persistent response at study end point did not significantly differ according to CYP2D6 heterozygous extensive metabolizer versus homozygous extensive metabolizer phenotype and ABCB1 polymorphisms in univariate analyses. After adjusting for age, sex, paroxetine concentration at week 2, and daily dose at study end point, ABCB1 genotype contributed to improving the model significantly for 61A>G (P = 0.043), but not 2677G>T (P = 0.068) and 3435C>T (P = 0.11). None of two poor metabolizers and four ultrarapid metabolizers showed persistent response to paroxetine. The hypothesis that permeability glycoprotein activity might be a relevant predictor of therapeutic response deserves to be further investigated while controlling for pharmacokinetic variability.     

Survival of a 30-week baby with congenital myotonic dystrophy initially ventilated for 55 days

In previous reports, duration of initial ventilation exceeding 1 month almost always predicts non-survival of babies with congenital myotonic dystrophy. However, a baby with this condition survived beyond infancy after 55 days' ventilation. We describe this case in detail, explain why the baby survived and highlight the importance of individualized assessment, in addition to applying general prognostic terms described in the literature.     

Compression médullaire lente par lipomatose épidurale thoracique idiopathique : cas clinique et revue de la littérature

We report the case of a patient with spinal cord compression evolving over 36 months with spastic paraparesis. Anatomic imagery showed epidural lipomatosis. No predisposing factors were found. Surgical treatment was decided. A T1-T10 laminectomy with excision of the surplus epidural fat was performed. Immediate and medium-term postsurgical follow-up was favorable with the disappearance of the pyramidal syndrome. Other cases found in literature and the principal predisposing factors are discussed.     

Erg?nzung und Unterstützung zu konventionellen Tumortherapien Misteltherapie

Die anthroposophische Misteltherapie kann etablierte onkologische Standardtherapien im Sinne einer umfassenderen und ganzheitlichen Versorgung erg?nzen.     

Contact sensitizers downregulate the expression of the chemokine receptors CCR6 and CXCR4 in a skin dendritic cell line

Chemokines are involved in the control of dendritic cell (DC) trafficking, which is critical for the immune response, namely in allergic contact dermatitis (ACD). In this work, we investigated by flow cytometry the effect of the contact sensitizers 2,4-dinitrofluorobenzene (DNFB), 1,4-phenylenediamine (PPD) and nickel sulfate (NiSO₄), on the surface expression of the chemokine receptors CCR6 and CXCR4 in DC. As an experimental model of a DC we used a fetal skin-derived dendritic cell line (FSDC), which has morphological, phenotypical and functional characteristics of skin DC. Our results show that all the skin sensitizers studied decreased the membrane expression of the chemokine receptors CCR6 and CXCR4. In contrast, 2,4-dichloronitrobenzene (DCNB), the inactive analogue of DNFB without contact sensitizing properties, was without effect on the surface expression of these receptors. Lipopolysaccharide (LPS), which induces the maturation of DC, also reduced surface CCR6 and CXCR4 expression.     

Neuro-ophthalmological manifestations of systemic lupus erythematosus in Asian patients

Purpose : To report eight patients with diagnosed systemic lupus erythematosus (SLE) who presented with a variety of neuro‐ophthalmological complications and outcomes. Methods : A review of the follow up, subsequent management and outcomes of the neuro‐ophthalmological complications of eight patients with SLE. Results : The patients presented with a myriad of symptoms of varying severities. The most common manifestations were that of optic neuropathy and eye movement abnormalities. The outcome was variable ranging from complete recovery to optic atrophy with navigational visual acuity. Treatment was often empirical, although early treatment with corticosteroids has been tried with varying success. Conclusions : The pathophysiology in the neuro‐ ophthalmological manifestations of SLE is thought be due to vaso‐occlusive disease of the small vessels of the nerve and brain, secondary to an autoimmune process. Ophthalmologists may need to consider the diagnosis of SLE in young women who present with a recent onset of neuro‐ophthalmological symptoms and signs.     

Undergraduate ophthalmology education survey of New Zealand ophthalmologists, general practitioners and optometrists

Aim : To determine what New Zealand ophthalmologists, general practitioners and optometrists consider important ophthalmic topic areas requiring emphasis in the medical undergraduate curriculum. Method : A total of 793 questionnaires related to the content and teaching of undergraduate ophthalmology were sent to ophthalmologists, general practitioners and optometrists. Results were analysed separately for the three respondent groups and as a whole. Results : Four hundred and fourteen questionnaires were returned (52% return rate). Overall responses of the three participant groups were similar and agreed favourably with the current curriculum. The ability to measure visual acuity (97%) and pupillary reflexes (93%), perform ophthalmoscopy (92%), and assess visual fields (68%) were regarded as ‘important or essential’ by the majority of respondents. Only 53% of respondents consider the ability to diagnose chronic open angle glaucoma as important. The respondents stressed the importance of the diagnosis of predominantly anterior segment disease contrasting with the traditional bias towards the teaching of ophthalmoscopy and posterior segment disease. The majority of respondents stressed the importance of graduating medical students being able to treat bacterial and allergic conjunctivitis, styes, blepharitis, corneal abrasion, and corneal and conjunctival foreign bodies, areas present but not normally emphasized in current curricula. Conclusion : The findings of this study provided additional data to facilitate curriculum design and illustrated the value of an integrated problem‐based learning approach in ophthalmology undergraduate teaching.     

混合造血干细胞移植后输注供者淋巴细胞和白细胞介素2对急性髓性白血病疗效的影响

目的:观察急性髓性白血病经混合造血干细胞移植后,应用供者淋巴细胞输注 白细胞介素2治疗的效果,并与移植后未经特殊治疗的效果进行比较。方法:①选取2000-01/2004-07解放军兰州军区兰州总医院全军血液病中心收治的19例急性髓性白血病患者,实验经医院伦理委员会批准,患者均知情同意。随机数字表法分为两组:观察组8例,年龄17～40岁,M2a 4例,M4 1例,M5a 3例;对照组11例,年龄19～39岁,M2a 2例,M3a 2例,M4 3例,M5a 4例。②两组患者采用化疗联合重组人粒细胞集落刺激因子的方法动员自体外周血造血干细胞,采集后液氮中保存5d备用。③术前采用直线加速器对患者全身及肺部照射,预处理完毕后实施混合造血干细胞移植。首先回输自体单个核细胞中位数为4×108/kg,CD34 细胞中位数为6.2×106/kg,粒-巨噬祖细胞集落形成单位中位数为5.8×104/kg。间隔1～6h后,采集人类白细胞抗原半相合异体骨髓,按回输自体单个核细胞数的1/6～1/10输注给患者。④两组患者移植期间均住无菌层流病房,给予相应并发症的防治及支持治疗。在粒细胞降至0时注射重组人粒细胞集落刺激因子150μg/12h,促进造血恢复。观察组给予供者淋巴细胞输注 白细胞介素2治疗,每次采集的供者淋巴细胞中,CD3 淋巴细胞中位数为1.43×108/kg,CD4 细胞中位数为0.97×108/kg,CD8 细胞中位数为0.41×108/kg,中位治疗次数4(1～7)次,回输后即开始应用100wu/d重组人白细胞介素2,共10d。对照组混合造血干细胞移植后未给予特殊治疗。结果:19例急性髓性白血病患者均进入结果分析。①造血恢复:两组患者均获得造血重建,术后4～9d粒细胞均降至0,12～17d粒细胞达0.5×109L-1,16～21d白细胞达4.0×108 L-1,19～23 d血小板达20×108 L-1。16～21 d骨髓检查示恢复期骨髓象。②术后并发症:两组患者不同程度地出现口腔溃疡,随着造血恢复,7～10d溃疡消失。观察组1例患者出现出血性膀胱炎,两组各2例患者出现发热。无肝静脉闭塞病和移植物抗宿主病发生。③嵌合体形成:观察组中1例M4患者形成嵌合体,对照组中2例M4患者与1例M5患者形成嵌合体,嵌合体持续存在3～12个月。④供者淋巴细胞输注 白细胞介素2疗效:观察组中有1例M2a患者在接受2次特殊治疗后7个月复发死亡;1例M2a患者接受2次特殊治疗后1年出现骨髓增生异常综合征,脑出血死亡,1例M5a患者应用特殊治疗1次后出现不明原因高热、抽搐,死于癫痫持续状态,其余5例患者随访2年均健康存活,长期生存率为62.5%(5/8)。对照组有2例M2a患者、2例M4患者、1例M5患者于移植后1～7个月复发死亡,1例M3患者于移植后25d死于脑出血,其余2例M3患者、2例M4患者、1例M5患者随访2年均健康存活,长期生存率为45.4%(5/11)。结论:混合造血干细胞移植后应用供者淋巴细胞输注 白细胞介素2治疗,急性髓性白血病患者均获得造血重建且无移植物抗宿主病发生,其长期生存率有效提高。