Relationships between drug exposure, changes in metabolic parameters and body fat in HIV-infected patients switched to a nucleoside sparing regimen.

BACKGROUND: The pathogenesis of metabolic disturbances in treated HIV infection is incompletely understood. METHODS: Relationships between fasted metabolic parameters, body composition, and drug plasma concentrations were investigated in 59 patients who switched from failed nucleoside analogue treatment to ritonavir-boosted indinavir and efavirenz therapy. Metabolic parameters, peripheral fat, visceral adipose tissue (VAT) and drug plasma concentrations were measured prospectively. RESULTS: Ritonavir exposure was found to be negatively correlated with high-density lipoprotein cholesterol (HDL-c) changes, with a 2.4% decrease in HDL-c for each unit increase in ritonavir concentration ratio. Significant associations between indinavir or efavirenz concentrations and metabolic disturbances were not observed. Total cholesterol (TC) correlated positively with high body mass index (BMI) and negatively with baseline limb fat mass: each unit increase in BMI and each kilogram reduction in baseline limb fat corresponded with a TC increase of 2.4% and 4.1%, respectively. Baseline triglyceride levels were lower in those patients with relatively greater limb fat mass: each kilogram reduction of total limb fat mass was associated with a 15.7% increase in triglyceride concentration. Changes in VAT were positively correlated with TC: for every unit TC increase a 0.3% VAT increase was observed (over 48 weeks). CONCLUSIONS: Reduced limb fat mass at the start of the study treatment, increases in VAT mass, and higher plasma concentrations of ritonavir on study treatment were each--to varying degrees--associated with various metabolic disturbances.

Nevirapine plasma concentrations and concomitant use of rifampin in patients coinfected with HIV-1 and tuberculosis.

OBJECTIVES: In countries with high numbers of HIV/tuberculosis coinfection nevirapine and rifampin are used extensively. However, limited data are available about whether or not nevirapine and rifampin can be safely coadministered without the plasma concentration of nevirapine falling below therapeutic levels. METHODS: Blood samples for determination of nevirapine plasma concentrations were collected from patients using nevirapine 200 mg twice daily with or without concomitant rifampin. Bivariate and multivariate linear regression models were used to investigate factors possibly related to nevirapine concentrations. RESULTS: We received 74 blood samples from patients using nevirapine plus rifampin, and collected blood samples from an equal number of controls using nevirapine only. Groups were similar for age, gender, weight, height and body mass index (BMI). In the rifampin group the mean nevirapine concentration was 5.47 +/- 2.66 mg/l, whereas in the control group the mean nevirapine concentration was 8.72 +/- 3.98 mg/l. In the rifampin group seven nevirapine trough concentrations were low (< 3.1 mg/l), while in the control group two patients had low nevirapine trough concentrations (P = 0.164). In the multivariate linear regression analysis, corrected for time after drug intake, the use of rifampin was significantly (P < 0.001) associated with lower nevirapine plasma concentrations, whereas higher BMI reached borderline significance (P = 0.065). CONCLUSION: Although nevirapine plasma concentrations were 3.3 mg/l lower when co-administered with rifampin, still more than 86% of these patients had nevirapine plasma concentrations > 3.1 mg/l. Our results suggest that from a pharmacological point of view the majority of Thai coinfected patients, who have low BMIs, reach nevirapine plasma concentrations that are adequate for treatment of HIV. However this can only be undertaken if nevirapine plasma concentration monitoring is available and can be closely followed.

MLL-SEPTIN6 fusion recurs in novel translocation of chromosomes 3, X, and 11 in infant acute myelomonocytic leukaemia and in t(X;11) in infant acute myeloid leukaemia, and MLL genomic breakpoint in complex MLL-SEPTIN6 rearrangement is a DNA topoisomerase II cleavage site.

We examined the MLL translocation in two cases of infant AML with X chromosome disruption. The G-banded karyotype in the first case suggested t(X;3)(q22;p21)ins(X;11)(q22;q13q25). Southern blot analysis showed one MLL rearrangement. Panhandle PCR approaches were used to identify the MLL fusion transcript and MLL genomic breakpoint junction. SEPTIN6 from chromosome band Xq24 was the partner gene of MLL. MLL exon 7 was joined in-frame to SEPTIN6 exon 2 in the fusion transcript. The MLL genomic breakpoint was in intron 7; the SEPTIN6 genomic breakpoint was in intron 1. Spectral karyotyping revealed a complex rearrangement disrupting band 11q23. FISH with a probe for MLL confirmed MLL involvement and showed that the MLL-SEPTIN6 junction was on the der(X). The MLL genomic breakpoint was a functional DNA topoisomerase II cleavage site in an in vitro assay. In the second case, the karyotype revealed t(X;11)(q22;q23). Southern blot analysis showed two MLL rearrangements. cDNA panhandle PCR detected a transcript fusing MLL exon 8 in-frame to SEPTIN6 exon 2. MLL and SEPTIN6 are vulnerable to damage to form recurrent translocations in infant AML. Identification of SEPTIN6 and the SEPTIN family members hCDCrel and MSF as partner genes of MLL suggests a common pathway to leukaemogenesis.