Biopsies of olfactory epithelium in patients with Parkinson's disease

Parkinson's disease (PD) is a neurodegenerative disorder involving several neuronal systems. Impaired olfactory function may constitute one of the earliest symptoms of PD. However, it is still unclear to what degree changes of the olfactory epithelium may contribute to dysosmia and if these changes are different from those of other hyposmic or anosmic patients. This study aimed to investigate the hypothesis that olfactory loss in PD is a consequence of specific PD-related damage of olfactory epithelium. Biopsies of 7 patients diagnosed with PD were taken. Six patients with PD were hyposmic, one anosmic. As non-PD controls served 9 patients with hyposmia, 9 with anosmia, and 7 normosmic individuals. Further, nasal mucosa of 4 postmortem individuals was investigated. Immunohistochemical examinations were performed with antibodies against olfactory marker protein (OMP), protein gene product 9.5 (PGP 9.5), beta-tubulin, (BT), proliferation-associated antigen (Ki 67), the stem cell marker nestin, cytokeratin, p75NGFr, and alpha-synuclein. Most of the biopsy specimens exhibited irregular areas of olfactory-like, dysplastic epithelium positive for either PGP 9.5 or BT, but negative for OMP. No major histochemical differences in either the expression or distribution of these proteins were observed in the olfactory epithelium of patients with PD compared with controls. Reverse transcription PCR (RT-PCR) data indicated mRNA for OMP in almost all subjects, independently of their olfactory performance. These data support the idea that olfactory loss in Parkinson's disease is not a consequence of damage to the olfactory epithelium but rather results from distinct central-nervous abnormalities.

An Ambystoma mexicanum EST sequencing project: analysis of 17,352 expressed sequence tags from embryonic and regenerating blastema cDNA libraries

An EST database has been generated for the axolotl Ambystoma mexicanum. Analysis of this data has uncovered an unusual phylogenetic distribution of the cyclin dependent kinase inhibitor 1 gene family in amphibians.

Background

The ambystomatid salamander, Ambystoma mexicanum (axolotl), is an important model organism in evolutionary and regeneration research but relatively little sequence information has so far been available. This is a major limitation for molecular studies on caudate development, regeneration and evolution. To address this lack of sequence information we have generated an expressed sequence tag (EST) database for A. mexicanum.

Results

Two cDNA libraries, one made from stage 18-22 embryos and the other from day-6 regenerating tail blastemas, generated 17,352 sequences. From the sequenced ESTs, 6,377 contigs were assembled that probably represent 25% of the expressed genes in this organism. Sequence comparison revealed significant homology to entries in the NCBI non-redundant database. Further examination of this gene set revealed the presence of genes involved in important cell and developmental processes, including cell proliferation, cell differentiation and cell-cell communication. On the basis of these data, we have performed phylogenetic analysis of key cell-cycle regulators. Interestingly, while cell-cycle proteins such as the cyclin B family display expected evolutionary relationships, the cyclin-dependent kinase inhibitor 1 gene family shows an unusual evolutionary behavior among the amphibians.

Conclusions

Our analysis reveals the importance of a comprehensive sequence set from a representative of the Caudata and illustrates that the EST sequence database is a rich source of molecular, developmental and regeneration studies. To aid in data mining, the ESTs have been organized into an easily searchable database that is freely available online.

Experimental induction of AGEs in fetal L132 lung cells changes the level of intracellular cathepsin D

The effect of the carbonyl compound glyoxal on the induction of advanced glycation end products (AGEs) in the fetal epithelial lung cells L132 was investigated using immunohistochemical, immunoelectron microscopic, and biochemical methods. It was found that glyoxal treatment resulted in morphological changes of the cells and in the membranous and cytosolic localization of AGEs such as methyl-glyoxal-derived compounds, N-(carboxymethyllysine) (CML) and imidazolone. The formation of AGEs was accompanied with a change in the intracellular expression of cathepsin D and a loss of enzymatic activity.