Histochemical approaches to assess cell-to-cell transmission of misfolded proteins in neurodegenerative diseases.

Formation, aggregation and transmission of abnormal proteins are common features in neurodegenerative disorders including Parkinson's disease, Alzheimer's disease, amyotrophic lateral sclerosis, and Huntington's disease. The mechanisms underlying protein alterations in neurodegenerative diseases remain controversial. Novel findings highlighted altered protein clearing systems as common biochemical pathways which generate protein misfolding, which in turn causes protein aggregation and protein spreading. In fact, proteinaceous aggregates are prone to cell-to-cell propagation. This is reminiscent of what happens in prion disorders, where the prion protein misfolds thus forming aggregates which spread to neighbouring cells. For this reason, the term prionoids is currently used to emphasize how several misfolded proteins are transmitted in neurodegenerative diseases following this prion-like pattern. Histochemical techniques including the use of specific antibodies covering both light and electron microscopy offer a powerful tool to describe these phenomena and investigate specific molecular steps. These include: prion like protein alterations; glycation of prion-like altered proteins to form advanced glycation end-products (AGEs); mechanisms of extracellular secretion; interaction of AGEs with specific receptors placed on neighbouring cells (RAGEs). The present manuscript comments on these phenomena aimed to provide a consistent scenario of the available histochemical approaches to dissect each specific step.

Effect of UVB plus tar therapy on serum levels of interleukin-2 receptors in patients with psoriasis.

Baseline serum levels of interleukin-2 receptor (IL2R) were measured in 65 patients with active psoriasis. IL2R levels in psoriatic patients were significantly higher than in healthy controls (582.4 +/- 289.23 u/ml vs. 369.64 +/- 111.10 u/ml; P less than 0.05), but did not differ statistically from values found in an atopic dermatitis control group (619.88 +/- 254.27 u/ml). Sex, age and severity of the disease do not affect levels of IL2R. The same IL2R levels were measured in 26 psoriatic patients receiving UVB plus tar therapy. This therapy, continued until clinical remission, lowered IL2R levels to values comparable to controls. This decrease may be due to an immunosuppressive effect of therapy.

[Seborrheic keratoses studied using scanning electron microscopy]. / Cheratosi seborroiche al S.E.M.

Ten seborrheic keratosis of acanthotic type have been observed by S.E.M. The morphological study could confirm the existence of two processes in the origin of the horny cysts which are peculiar to this affection. a) an extrafollicular process causes the involvement of groups of keratinocytes which, by assuming a vortex disposition, produce a concentric keratinization; b) a follicular process which causes an accentuated keratinization of the cells surrounding the epithelial sheath. This process was associated to the presence of multiple hairs a single follicle. Moreover, with higher magnification, it was possible to observe a great number of bacteria, yeasts and of particular alteration of the membrane which could be compared to changes in the tone filaments.