Impact of suggestion on the human experimental model of cold hyperalgesia after topical application of high-concentration menthol [40%].

BACKGROUND: Human experimental pain models in healthy subjects offer unique possibilities to study mechanisms of pain within a defined setting of expected pain symptoms, signs and mechanisms. Previous trials in healthy subjects demonstrated that topical application of 40% menthol is suitable to induce cold hyperalgesia. The objective of this study was to evaluate the impact of suggestion on this experimental human pain model. METHODS: The study was performed within a single-centre, randomized, placebo-controlled, double-blind, two-period crossover trial in a cohort of 16 healthy subjects. Subjects were tested twice after topical menthol application (40% dissolved in ethanol) and twice after ethanol (as placebo) application. In the style of a balanced placebo trial design, the subjects received during half of the testing the correct information about the applied substance (topical menthol or ethanol) and during half of the testing the incorrect information, leading to four tested conditions (treatment conditions: menthol-told-menthol and menthol-told-ethanol; placebo conditions: ethanol-told-menthol and ethanol-told-ethanol). RESULTS: Cold but not mechanical hyperalgesia was reliably induced by the model. The cold pain threshold decreased in both treatment conditions regardless whether true or false information was given. Minor suggestion effects were found in subjects with prior ethanol application. CONCLUSIONS: The menthol model is a reliable, nonsuggestible model to induce cold hyperalgesia. Mechanical hyperalgesia is not as reliable to induce. SIGNIFICANCE: Cold hyperalgesia may be investigated under unbiased and suggestion-free conditions using the menthol model of pain.

A thorough QT/QTc study of multiple doses of tapentadol immediate release in healthy subjects.

OBJECTIVE: This randomized, double-blind, placebo- and positive-controlled 4-way crossover study evaluated the effects of tapentadol immediate release (IR) on the QT/QTc interval. MATERIALS AND METHODS: Healthy subjects received tapentadol IR 100 mg or 150 mg, or placebo, every 6 h on Days 1 and 2, with a >= 7-day washout between treatments. Moxifloxacin 400 mg was the positive control. Serial triplicate 12-lead electrocardiograms (ECGs) were performed; the Fridericia correction (QTcF) was the primary correction method. Serial blood sampling was performed for pharmacokinetic analyses. RESULTS: Of the 75 subjects who were randomized, 68 received at least 1 dose of study medication, and 59 completed the study. Upper limits of the 90% confidence intervals (CIs) for the difference in mean DeltaQTcF between tapentadol IR 100 or 150 mg and placebo were < 10 ms (non-inferiority criterion) for all time points. The lower limit of the 90% CI for mean DeltaQTcF between moxifloxacin and placebo exceeded 5 ms from 1 to 6 h after dosing, establishing assay sensitivity. No subject had a postdose QTc interval > 480 ms, change from baseline > 60 ms, or clinically relevant change in heart rate or other ECG variables. Steady-state concentrations were reached within 18 to 24 h. Common adverse events were vertigo (central nervous system (CNS) origin), headache, somnolence, nausea, vomiting, and feeling drunk. CONCLUSION: Therapeutic and supratherapeutic doses of tapentadol do not affect the QT/QTc interval.

Reduction in non-glomerular renal clearance of the caffeine metabolite 1-methylxanthine by probenecid.

OBJECTIVE: Urinary caffeine metabolic ratios used to quantify the activity of numerous drug-metabolizing enzymes are an established component of cocktail approaches for metabolic phenotyping. Because in vitro evidence suggests that 1-methylxanthine (1-MX), a major caffeine metabolite, is actively secreted into urine by organic anion transporters (hOATs), coadministration of renal hOAT inhibitors like probenecid may impair these procedures. METHODS: In a randomized, placebo-controlled, double-blind crossover design, single oral doses of 300 mg caffeine with oral coadministration of placebo or 500 mg probenecid 3 times daily for 2 days were administered to 7 healthy men. The plasma and urine concentrations of caffeine and its major metabolites 1,7-dimethylxanthine (1,7-DMX) and 1-MX were determined by high-performance liquid chromatography. RESULTS: Coadministration of probenecid resulted in a 34% reduction of the renal clearance of 1-MX (mean +/- SD 190 +/- 42 versus 290 +/- 83 ml min(-1), 95% CI on difference 0.2, 200, p = 0.04) with a 41% reduction in its estimated non-glomerular clearance. The renal clearances of caffeine and 1,7-DMX and the area under the plasma concentration-time curves of all substances were not significantly changed. CONCLUSIONS: 1-MX undergoes renal tubular secretion which is substantially reduced by probenecid, possibly due to inhibition of renal hOATs. This inhibition may explain the influence of probenecid on urinary caffeine metabolic ratios and, thus, its impact on the assessment of enzyme activities. It also suggests that 1-MX might serve as a model substrate for the renal tubular transport of organic anions.

Successful treatment with voriconazole of Aspergillus brain abscess in a boy with medulloblastoma.

Invasive aspergillosis is an increasing problem in immuno-incompetent patients after prolonged steroid therapy, cancer radio-chemotherapy, and bone marrow or solid organ transplantation. Cerebral aspergillosis is a well-described complication of the invasive aspergillosis but only in rare cases, the brain is the sole site of infection. Despite increasing availability of antifungal drugs, the prognosis of cerebral aspergillosis is poor. We report on an 11-year-old boy with medulloblastoma in the area of the fourth ventricle. Following tumor surgery and radio-chemotherapy, several abscess-like structures occurred in the operating field. After incomplete abscess, resection histology and culture confirmed a localized Aspergillus fumigatus infection. The initial treatment of the Aspergillus fumigatus infection with conventional amphotericin B failed, and treatment with the triazole voriconazole was started. Intravenous treatment with voriconazole resulted in a reduction of the Aspergillus fumigatus abscess. After switching to oral ambulatory therapy, the Aspergillus fumigatus abscess increased in size. To improve treatment, voriconazole dosage was adapted to reach drug concentrations in cerebrospinal fluid (CSF) above the minimal fungicidal concentration and plasma specimens. During the concentration-controlled voriconazole therapy for a period of 18 months, a complete response was achieved.

ADME transcriptome in Hispanic versus White donor livers: evidence of a globally enhanced NR1I3 (CAR, constitutive androstane receptor) gene signature in Hispanics.

Previous studies have found that, compared with Whites, Hispanic donor livers had elevated expression of CYP2 enzymes, gene products regulated by the constitutive androstane receptor (CAR). The objectives of the current study were to determine (1) the CAR activation signature in human liver (2) whether other drug detoxification (absorption, distribution, metabolism and excretion (ADME)) genes were differentially expressed in Hispanic versus White livers, and (3) the extent of overlap in the CAR and Hispanic liver transcriptomes. The CAR transcriptome (ADME genes differentially expressed following phenobarbital versus vehicle treatment of human hepatocytes) and the Hispanic liver transcriptome (ADME genes differentially expressed in Hispanic versus White livers) were identified using Affymetrix oligonucleotide arrays. Quantitative real-time polymerase chain reaction (PCR) was used to verify candidate genes in a larger sample size. Comparison of the CAR and Hispanic liver ADME transcriptomes revealed a significant association between the gene changes. Sixty-four per cent of the ADME genes induced more than twofold by phenobarbital were also induced in Hispanics, and 14% of the ADME genes repressed more than twofold by phenobarbital were repressed in Hispanics. In conclusion, compared with Whites, Hispanic donor livers have increased expression of many genes that are transcriptionally regulated by CAR. This result has practical implications to the drug treatment of Hispanic patients.

Effects of a divided high loading dose of caffeine on circulatory variables in preterm infants.

BACKGROUND: A single high loading dose of 25 mg/kg caffeine has been shown to be effective for the prevention of apnoea, but may result in considerable reductions in blood flow velocity (BFV) in cerebral and intestinal arteries. OBJECTIVE: To assess the effects of two loading doses of 12.5 mg/kg caffeine given four hours apart on BFV in cerebral and intestinal arteries, left ventricular output (LVO), and plasma caffeine concentrations in preterm infants. DESIGN: Sixteen preterm neonates of <34 weeks gestation were investigated one hour after the first oral dose and one, two, and 20 hours after the second dose by Doppler sonography. RESULTS: The mean (SD) plasma caffeine concentrations were 31 (7) and 29 (7) mg/l at two and 20 hours respectively after the second dose. One hour after the first dose, none of the circulatory variables had changed significantly. One hour after the second caffeine dose, mean BFV in the internal carotid artery and anterior cerebral artery showed significant reductions of 17% and 19% (p = 0.01 and p = 0.003 respectively). BFV in the coeliac artery and superior mesenteric artery, LVO, PCO2, and respiratory rate had not changed significantly. Total vascular resistance, calculated as the ratio of mean blood pressure to LVO, had increased significantly one and two hours after the second dose (p = 0.049 and p = 0.023 respectively). CONCLUSION: A divided high loading dose of 25 mg/kg caffeine given four hours apart had decreased BFV in cerebral arteries after the second dose, whereas BFV in intestinal arteries and LVO were not affected.

[Familial Mediterranean fever. New aspects with respect to molecular genetics and pathogenesis revealed in three case reports]. / Familiäres Mittelmeerfieber. Neue Aspekte zur molekularen Genetik und Pathogenese am Beispiel dreier Fallbeschreibungen.

HISTORY AND CLINICAL PRESENTATION: Three young Turkish males were admitted because of acute abdominal pain and fever. All 3 patients had recurrent attacks of these symptoms every few weeks since years with each attack lasting 2 to 3 days. One patient developed a renal amyloidosis with an end-stage renal failure. DIAGNOSTICS AND CLINICAL COURSE: All patients presented with local abdominal tenderness and an elevation of inflammatory parameters (WBC, ESR, CRP and fibrinogen). X-ray studies, ultrasound and upper endoscopy were normal. In 1 patient histology yielded amyloid fibrils in the antrum of the stomach. In a molecular genetic analysis 2 patients were compound heterozygous for 2 common mutations of the gene responsible for the familial Mediterranean fever (FMF). In all patients the symptoms vanished spontaneously according to an acute attack of FMF. After symptomatic treatment a prophylaxis with colchicine was started. CONCLUSION: Cloning of the FMF gene and its mutations and identification of the gene product "pyrin" reveals new aspects on genetics and pathophysiology. The improved diagnostic procedure enables an early start of colchicine treatment, especially to prevent renal amyloidosis.