P16 expression in relation to human papillomavirus in liquid-based cervical smears.

OBJECTIVE: At present, a simple and reliable cervical cancer screening test remains to be perfected. As overexpression of the protein p16 is correlated with the presence of high-risk HPV in malignant cervical lesions, this protein has been proposed as a surrogate marker of high-risk HPV infection in cervical cancer screening. Since high-risk viral DNA integration is necessary for neoplastic progression, we aimed to examine the expression of p16 in relation to the physical status of HPV (integrated or episomal) on liquid-based cervical smears. METHODS: For each of the 241 liquid-based cervical smear included in our study, we realized a Pap test. Residual cells were processed for in situ hybridization with mucosal HPV DNA probes and for immunocytochemistry with an anti-p16 antibody. Integrated or episomal copies of HPV DNA were detected as dotted or diffuse signals, respectively. RESULTS: In high-grade intraepithelial lesions, both the integrated form of high-risk HPV and overexpression of p16 were detected. However, we observed the presence of some p16-positive/HPV-negative normal and ASCUS smears. Moreover, some p16-negative ASCUS smears and low-grade intraepithelial lesions harbored episomal high-risk HPV. CONCLUSION: If p16 was used as a surrogate marker of high-risk HPV infection, some women would be scored negative in spite of the presence of high-risk HPV. These women are more likely to undergo cancer progression, but no follow-up would be proposed to them in that screening pathway. A possible compromise for the triage of abnormal cervical smears should be a combination of both HPV and p16 testing.

Cytokine expression in rat colon during postnatal development: regulation by glucocorticoids.

OBJECTIVES: Cytokine expression and regulation by glucocorticoids and retinoic acid were investigated in the colon during postnatal development. MATERIALS AND METHODS: Gene expression of the transforming growth factors (TGFs) TGF-beta1, TGF-beta2 and TGF-alpha and the proinflammatory cytokines tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) was evaluated by reverse transcription-polymerase chain reaction (RT-PCR) in rat colon mucosa during weaning and in adult rats. Protein expression and distribution of TGF-betas was analysed in the colon from 14- and 60-day-old animals. The effect of hydrocortisone administration on mucosal cytokine transcripts (RT-PCR) and of dexamethasone on the expression of cytokines by the epithelial cell line IEC-18 and 2 subepithelial myofibroblasts (MIC 307-1 and 316) was examined. RESULTS: TGF-beta1 and TGF-beta2 messenger RNAs and proteins decreased in the entire colon from weaning to adult stages, whereas the amount of TGF-alpha messenger RNA increased in the proximal colon and decreased in the distal part of the colon in adult rats in comparison with weanlings. However, proinflammatory cytokines showed no postnatal changes in the proximal colon but decreased in the distal part in comparison with weaning rats. Hydrocortisone treatment did not affect growth factor expression but decreased proinflammatory cytokines. Likewise, dexamethasone decreased TNF-alpha and IL-1beta gene expression but did not affect TGF-betas in either epithelial or myofibroblast cells. CONCLUSIONS: During postnatal maturation, the expression of growth factors and proinflammatory cytokines decreased in the distal colon, whereas in the proximal colon, a differential maturation occurs with no changes in proinflammatory cytokines, an increase in TGF-alpha and a decrease in TGF-beta. Glucocorticoids may control the developmental profile of proinflammatory cytokines.

HPV DNA detection by in situ hybridization with catalyzed signal amplification on thin-layer cervical smears.

Thin layer-based technology in cervical cancer screening now allows both Papanicolaou staining and HPV testing on the same sample. Here, we show that in situ hybridization with catalyzed reporter deposition is a powerful HPV detection method when applied on thin-layer cervical smears, allowing distinction between two staining patterns suggestive of two different physical states of HPV DNA, where diffuse signals are suggestive of episomes and punctate signals are suggestive of viral DNA integration.

Loss of STOP protein impairs peripheral olfactory neurogenesis.

BACKGROUND: STOP (Stable Tubulin-Only Polypeptide) null mice show behavioral deficits, impaired synaptic plasticity, decrease in synaptic vesicular pools and disturbances in dopaminergic transmission, and are considered a neurodevelopmental model of schizophrenia. Olfactory neurons highly express STOP protein and are continually generated throughout life. Experimentally-induced loss of olfactory neurons leads to epithelial regeneration within two months, providing a useful model to evaluate the role played by STOP protein in adult olfactory neurogenesis. METHODOLOGY/PRINCIPAL FINDINGS: Immunocytochemistry and electron microscopy were used to study the structure of the glomerulus in the main olfactory bulb and neurogenesis in the neurosensorial epithelia. In STOP null mice, olfactory neurons showed presynaptic swellings with tubulovesicular profiles and autophagic-like structures. In olfactory and vomeronasal epithelia, there was an increase in neurons turnover, as shown by the increase in number of proliferating, apoptotic and immature cells with no changes in the number of mature neurons. Similar alterations in peripheral olfactory neurogenesis have been previously described in schizophrenia patients. In STOP null mice, regeneration of the olfactory epithelium did not modify these anomalies; moreover, regeneration resulted in abnormal organisation of olfactory terminals within the olfactory glomeruli in STOP null mice. CONCLUSIONS/SIGNIFICANCE: In conclusion, STOP protein seems to be involved in the establishment of synapses in the olfactory glomerulus. Our results indicate that the olfactory system of STOP null mice is a well-suited experimental model (1) for the study of the mechanism of action of STOP protein in synaptic function/plasticity and (2) for pathophysiological studies of the mechanisms of altered neuronal connections in schizophrenia.