The Discriminatory Value of CYP2D6 Genotyping in Predicting the Dextromethorphan/Dextrorphan Phenotype in Women with Breast Cancer

BACKGROUND: The growth inhibitory effect of tamoxifen is used for the treatment of breast cancer. Tamoxifen efficacy is mediated by its biotransformation, predominantly via the cytochrome P450 2D6 (CYP2D6) isoenzyme, to the active metabolite endoxifen. We investigated the relationship of CYP2D6 genotypes to the metabolism of dextromethorphan (DM), which is frequently used as a surrogate marker for the formation of endoxifen. METHODS: The CYP2D6 genotype was determined by polymerase chain reaction (PCR) in previously untreated patients with hormone receptor-positive invasive breast cancer considered to receive antihormonal therapy. The DM/dextrorphan (DX) urinary excretion ratios were obtained in a subset of patients by high-pressure liquid chromatography (HPLC)-mediated urine analysis after intake of 25 mg DM. The relationships of genotype and corresponding phenotype were statistically analyzed for association. RESULTS: From 151 patients predicted based on their genotype data for the 'traditional' CYP2D6 phenotype classes poor, intermediate, extensive and ultrarapid, 83 patients were examined for their DM/DX urinary ratios. The genotype-based poor metabolizer status correlated with the DM/DX ratios, whereas the intermediate, extensive and ultrarapid genotypes could not be distinguished based on their phenotype. Citalopram intake did not significantly influence the phenotype. CONCLUSIONS: The DM metabolism can be reliably used to assess the CYP2D6 enzyme activity. The correlation with the genotype can be incomplete and the metabolic ratios do not seem to be compromised by citalopram. DM phenotyping may provide a standardized tool to better assess the CYP2D6 metabolic capacity.     

Use of the Goldman Technique to Correct Both the Overprojected and the Broad Nasal Tip

Background  

Tip surgery probably is the most challenging objective in modern rhinoplasty. The Goldman technique, despite its 50 years of history and its many variations proposed in the past, still remains a powerful tool for the surgeon who has to deal with an overprojected or broad nasal tip.     

Liver involvement in acute vaso-occlusive crisis of sickle cell disease: Prevalence and predisposing factors

Objective. To study the prevalence and predisposing factors of liver involvement in sickle cell disease (SCD) of patients with acute vaso-occlusive crisis. Material and methods. We prospectively evaluated 41 consecutive patients (44% M, median age 39 years, range 16–56 years) with homozygous (HbSS; 12 cases) or sickle cell-beta thalassemia (HbSβ-thal; 29 cases), admitted to our Medical Department in the period 2002 to 2004. Severity of crisis was graded by in-house-modified APACHE score; presence of asplenia or functional hyposplenism was also considered. Hematological and biochemical parameters including various relevant enzymes/isoenzymes were followed daily. Results. Despite the fact that only 9 patients (22%) presented with acute painful hepatomegaly, liver involvement was evident in 16 (39%); hepatocellular-type injury was found in 1 patient, cholestatic in 8, and mixed in 7. Severity of crisis was not related to liver involvement (score 20.6 versus 18.2), but liver involvement occurred in the presence of normal spleen function (p<0.001) and platelet counts <500,000/mm³ (p<0.001) were. Patients with liver involvement, compared with those without, had higher total and direct bilirubin levels (4.3 versus 2.9 mg/dL, p=0.050; 1.9 versus 0.8 mg/dL, p=0.010, respectively), lower hematocrit (19% versus 23%, p=0.030) and longer hospitalization (10 versus 6.3 days, p<0.001). Conclusions. In SCD, there is a 39% prevalence of acute veno-occlusive involvement of the liver, a figure that is much higher than previously reported. The type of injury is mostly mixed hepatocellular-cholestatic or purely cholestatic and its course is usually benign. Liver involvement occurs more often in patients with normal spleen function and is not associated with the overall severity of the acute episode, both observations being unreported previously.