Redox control of hepatic cell death

In necrotic liver failure like upon acetaminophen overdose, loss of the major intracellular thiol antioxidant glutathione was shown to be causal for hepatic dysfunction. In sharp contrast, fulminant apoptotic liver destruction upon overstimulation of the death receptors TNFR1 and CD95 was not associated with reduced hepatic glutathione levels. In view of the importance of the role of reactive oxygen intermediates versus antioxidants for apoptosis, we investigated the effect of phorone-induced enzymatic GSH depletion on the sensitivity of the liver towards CD95- or TNFR1-mediated hepatotoxicity. Our findings demonstrate in vivo that receptor-mediated hepatic apoptosis is disabled when glutathione is depleted, i.e. that an intact glutathione status is a critical determinant for the execution of apoptosis. In vitro, we did mechanistic studies in lymphoid cell lines and found that pro-caspase-8 at the CD95 death receptor and the mitochondrial activation of pro-caspase-9 are the enzyme targets that require sufficient intracellular reduced glutathione for their activation.     

Dual rate-dependent cardiac electrophysiologic effects of haloperidol: slowing of intraventricular conduction and lengthening of repolarization

Treatment with the neuroleptic agent haloperidol is sometimes associated with serious cardiac arrhythmias. The proarrhythmic potential of haloperidol may be linked to the drug's rate-dependent modulation of cardiac impulse conduction and repolarization. Herein these heart rate-dependent electrophysiologic actions of haloperidol are investigated in vivo. In anesthetized guinea pigs, haloperidol (0.02 mg/kg/min intravenously) produced significant rate-dependent slowing of intraventricular conduction. On abruptly changing the driving cycle length from 500 ms to 300 ms, conduction slowing rapidly reached a new steady state with a rate constant of 0.80 per beat +/- 0.07. The time course of recovery from conduction slowing on interruption of rapid pacing at a cycle length of 250 ms was well described by two time constants, tau(rec1) = 18.9 ms +/- 8.0 and tau(rec2) = 141.8 ms +/- 87.1, suggesting rapid dissociation of the drug from the Na+ channel. During prolonged stimulation, conduction slowing had a biphasic dependence on heart rate: for each 10-bpm increment in heart rate, conduction slowing increased by 7.9% at rates <220 bpm and by 17% at rates >220 bpm. At all tested cycle lengths, haloperidol caused a significant lengthening of Q(T) intervals, which was inversely dependent on heart rate. Numeric analysis suggested that the excessive increase in conduction slowing at rates >220 bpm was due to the drug's Q(T)-prolonging effect, indicating that, at short cycle lengths, the impulses encroached on the refractory period. Thus, in vivo, haloperidol slows intracardiac conduction with rapid on/off kinetics, comparable to the class I antiarrhythmic agent lidocaine. The Q(T) prolongation by haloperidol may lead to an excessive conduction slowing at high heart rates.     

Comparison of 4 methods for quantifying posterior capsule opacification

PURPOSE: To compare the results of posterior capsule opacification (PCO) quantification and the repeatability of a fully automated analysis system (Automated Quantification of After-Cataract [AQUA]) with that of 2 other quantification methods and subjective grading of PCO. A test set of digital retroillumination images of 100 eyes with PCO of varying degrees was used. SETTING: Department of Ophthalmology, University of Vienna, Vienna, Austria. METHODS: One hundred digital retroillumination images of eyes (100 patients) with PCO were selected to attain an even distribution from mild to severe cases. The images were evaluated by 4 methods: subjective grading by 4 experienced and 4 inexperienced examiners, the subjective Evaluation of Posterior Capsular Opacification (EPCO) system, posterior capsule opacification (POCO) software, and the AQUA system. Ten images were presented twice to assess the reproducibility of the analysis systems. RESULTS: Subjective grading correlated best with the subjective EPCO system and the objective AQUA system (r = 0.94 and r = 0.93, respectively). The POCO system showed very early saturation and therefore a much weaker correlation (r = 0.73). The POCO scores reached the maximum of 100% in several minimal to mild PCO cases. The reproducibility of the AQUA software was perfect and that of the other analysis systems, comparably satisfactory. CONCLUSION: The objective AQUA score correlated well with subjective methods including the EPCO system. The POCO system, which assesses PCO area, did not adequately describe PCO intensity and includes a subjective step in the analysis process. The AQUA system could become an important tool for randomized masked trials of PCO inhibition.     

‘Eosinophilic Fungal Rhinosinusitis’: A Common Disorder in Europe?

OBJECTIVES/HYPOTHESIS: The traditional criteria for the diagnosis of allergic fungal sinusitis include chronic rhinosinusitis, "allergic mucin" (mucus containing clusters of eosinophils), and detection of fungi by means of histological examination or culture. In 1999, a group of Mayo Clinic researchers, with a novel method of mucus collection and fungal culturing technique, were able to find fungi in 96% of patients with chronic rhinosinusitis. Immunoglobulin E-mediated hypersensitivity to fungal allergens was not evident in the majority of their patients. Because the presence of eosinophils in the allergic mucin, not a type I hypersensitivity, is probably the common denominator in the pathophysiology of allergic fungal sinusitis, the Mayo Clinic group proposed a change in terminology from allergic fungal sinusitis to eosinophilic fungal rhinosinusitis. Using new techniques of culturing fungi from nasal secretion, as well as preservation and histological examination of mucus, we investigated the incidence of "eosinophilic fungal rhinosinusitis" in our patient population. STUDY DESIGN METHODS: In an open prospective study nasal mucus from patients with chronic rhinosinusitis as well as from healthy volunteers was cultured for fungi. In patients, who underwent functional endoscopic sinus surgery, nasal mucus was investigated histologically to detect fungi and eosinophils within the mucus. RESULTS: Fungal cultures were positive in 84 of 92 patients with chronic rhinosinusitis (91.3%). In all, 290 positive cultures grew 33 different genera, with 3.2 species per patient, on average. Fungal cultures from a control group of healthy volunteers yielded positive results in 21 of 23 (91.3%). Histologically, fungal elements were found in 28 of 37 patients (75.5%) and eosinophilic mucin in 35 of 37 patients (94.6%). Neither fungi nor eosinophils were present in 2 of 37 patients (5.4%). CONCLUSIONS: Our data show that the postulated criteria of allergic fungal sinusitis are present in the majority of patients with chronic rhinosinusitis. Either those criteria will be found to be invalid and need to be changed or, indeed, "eosinophilic fungal rhinosinusitis" exists in the majority of patients with chronic rhinosinusitis. Based on our results, fungi and eosinophilic mucin appear to be a standard component of nasal mucus in patients with chronic rhinosinusitis.     

Non-invasive screening for GJB2 mutations in buccal smears for the diagnosis of inherited hearing impairment

BACKGROUND: Approximately 1 out of 1000 children is affected by severe or profound hearing impairment at birth. In the last years it has been shown that more than 50 % of inherited prelingual, sensorineural hearing impairment may be attributed to genetic defects. Most commonly, the GJB2 gene (chromosome 13q11) that encodes connexin 26 (Cx26) is affected. Cx26 is crucial for the formation of gap junctions which play an important role in the intercellular exchange of electrolytes. A variety of autosomal recessive GJB2 mutations associated with inherited hearing impairment has meanwhile been identified. The most common GJB2 mutation in Caucasian populations, 35delG accounts for the majority of cases and has a carrier frequency of more than 2.5 %. Other distinct mutations account for hearing impairment in other parts of the world. MATERIAL AND METHODS: We examined in 59 Caucasian and Ghanaian individuals whether DNA recovered from buccal smears was appropriate for genetic testing by polymerase-chain reaction (PCR) based DNA-sequencing. RESULTS: Buccal smears could be taken conveniently in all cases, even from small babies. In 53 out of 59 samples the material recovered from buccal smears could be subjected to PCR of the second exon of the GJB2 gene and subsequent DNA-sequencing. GJB2 mutations were identified in 34 patients. 13 Caucasian individuals exhibited the most common mutation 35delG. In addition, four cases of the rare W24X and each one heterozygous case of the V153I- and the L90P mutation were found. In two African individuals the 35insG mutation was detected. All other African patients had mutations exclusively identified in Ghana so far with the exception of R143W. R143W accounts for most cases of profound deafness in Ghana and has been identified in low frequencies in other ethnic groups as well. CONCLUSION: Screening for GJB2 mutations in DNA recovered from buccal smears of individuals with inherited hearing impairment offers an easy, non-invasive method for early diagnosis and a basis of genetic counselling.     

Human papillomavirus DNA in sera of cervical cancer patients as tumor marker

Persistent infection with human papillomavirus (HPV) has been widely recognized to induce carcinoma of the uterine cervix. Viral DNA has been documented to occur as tumor DNA in the circulation of patients with primary tumors caused by viral infection. The aim of this study was to evaluate the utility of serum HPV DNA as tumor marker in cervical cancer patients. Sera taken from 94 cervical cancer patients at the date of diagnosis and follow-up serum samples from 24 patients were examined for HPV DNA using PCR enzyme immunoassay. Serum samples taken at the date of diagnosis were HPV DNA positive in 45% of all investigated samples. Sera which were HPV DNA positive at the time of diagnosis became and also remained negative after primary treatment in patients without recurrence or persistent disease. HPV DNA was positive up to 423 days before the time of clinical diagnosis of recurrence in 10 out of 13 cases (median 72 days, range 0-423 days). Serum HPV DNA seems to reflect biological activity of the tumor. Our results indicate that serum HPV DNA might be a useful additional marker for early detection of recurrence in cervical cancer patients.