Risk Factors for Aggressive Recurrent Respiratory Papillomatosis in Adults and Juveniles

In this cohort study we examined whether gender, age at onset, observation time or human papillomavirus (HPV) genotype are risk factors for an aggressive clinical course in Recurrent Respiratory Papillomatosis (RRP). Clinical data from patient records comprised gender, age at onset, date of first endolaryngeal procedure with biopsy, date of last follow-up, total number of endolaryngeal procedures, and complications during the observation period. Disease was defined as juvenile (JoRRP) or adult onset (AoRRP) according to whether the disease was acquired before or after the age of 18. Aggressive disease was defined as distal spread, tracheostomy, four surgical operations annually or >10 surgeries in total. DNA was extracted from formalin-fixed paraffin-embedded tissue. HPV genotyping was performed by quantitative PCR assay identifying 15 HPV genotypes. The study included 224 patients. The majority were males (141/174 in AoRRPs and 31/50 in JoRRPs; p = 0.005). The median follow-up from initial diagnosis was 12.0 years (IQR 3.7–32.9) for JoRRPs and 4.0 years (IQR 0.8–11.7) for AoRRPs. The disease was more aggressive in juveniles than adults (p<0.001), a difference that disappeared after 10 years'' observation. JoRRPs with aggressive disease were younger at onset (mean difference 4.6 years, 95%CI [2.4, 6.8], p = 0.009). HPV6 or −11 was present in all HPV-positive papillomas. HPV11 was more prevalent in aggressive disease, and HPV6 in non-aggressive disease (p<0.001). Multiple logistic regression revealed that only age at onset (OR = 0.69, 95% CI [0.53, 0.88], p = 0.003) was associated with aggressive disease in juveniles, while HPV11 (OR = 3.74, 95% CI [1.40, 9.97], p = 0.008) and observation time >10 years (OR = 13.41, 95% CI [5.46, 32.99[, p<001) were risk factors in adults. In conclusion, the only significant risk factor for developing aggressive disease in JoRRPs was age at onset, but both HPV11 and observation time >10 years were risk factors for an aggressive disease course in AoRRPs.     

Flash-photolysis studies of the electron transfer from genetically modified spinach plastocyanin to photosystem I.

Plastocyanin (Pc) has been modified by site-directed mutagenesis at two separate electron-transfer (ET) sites: Leu-12-Glu at a hydrophobic patch, and Tyr-83-His at an acidic patch. The reduction potential at pH 7.5 is decreased by 26 mV in Pc(Leu-12-Glu) and increased by 35 mV in Pc(Tyr-83-His). The latter mutant shows a 2-fold slower intracomplex ET to photosystem I (PSI) as expected from the decreased driving force. The affinity for PSI is unaffected for this mutant but is drastically decreased for Pc(Leu-12-Glu). It is concluded that the hydrophobic patch is more important for the ET to PSI.     

Localization of ribonucleotide reductase in mammalian cells.

The results of immunocytochemical studies using two different monoclonal antibodies against the M1 subunit of ribonucleotide reductase show an exclusively cytoplasmic localization of this subunit both in cultured MDBK and mouse 3T6 cells, and in cells from various rat tissues. By fluorescent light microscopy, there is a diffuse staining of the cytoplasm, while by electron microscopy the immunoreactive material appears to be associated with ribosomes. In the rat tissues, only actively dividing cells show M1-specific immunofluorescence revealing a strong correlation between the presence of protein M1 and DNA synthesis. Therefore M1 immunofluorescence could be used to study cell proliferation in normal, inflammatory or neoplastic tissue. A lesser variation in M1 staining is observed between individual cells in tissue culture, where most cells are positive, but neither here nor in the tissues examined are any cells with nuclear staining detected. We interpret our results to mean that in mammalian cells ribonucleotide reduction takes place in the cytoplasm and from there the deoxyribonucleotides are transported into the nucleus to serve in DNA synthesis.     

Mitochondrial accumulation of APP and Aβ: significance for Alzheimer disease pathogenesis

Accumulating evidence suggest that alterations in energy metabolism are among the earliest events that occur in the Alzheimer disease (AD) affected brain. Energy consumption is drastically decreased in the AD-affected regions of cerebral cortex and hippocampus pointing towards compromised mitochondrial function of neurons within specific brain regions. This is accompanied by an elevated production of reactive oxygen species contributing to increased rates of neuronal loss in the AD-affected brain regions. In this review, we will discuss the role of mitochondrial function and dysfunction in AD. We will focus on the consequences of amyloid precursor protein and amyloid-β peptide accumulation in mitochondria and their involvement in AD pathogenesis.