Transmission héréditaire de l’information épigénétique par le gamète mâle

What determines phenotype is one of the most fundamental questions in biology. Historically, most studies have focused on genetics but more recent studies have revealed the existence of epigenetic modifications that are not based on DNA sequencing but are essential for appropriate gene expression. Importantly, these epigenetic modifications can be inherited by the offspring. Thus, both male and female gametes contain inherited epigenetic information.     

Kyste du tractus thyréoglosse dégénéré révélant un microcarcinome papillaire multifocal de la thyroïde

The malignant degeneration of thyroglossal duct cyst (TDC) is a very rare phenomenon. It occurs 1% of operated cysts where papillary carcinoma represents the most frequent pathological type. The authors report a clinical observation of a papillary carcinoma of thyroid occurring in a thyroglossal duct cyst concomitant to a multifocal micropapillary thyroid discovered in a 21-year-old woman. A total thyroidectomy was performed. A complementary treatment by radioactive iodine 131 (3,7 GBq) was undertaken. Two years later, the patient is doing well and does not present any sign of recurrence. In the light of this observation, the authors propose to report the diagnosis and therapeutic aspects of degenerated thyroglossal duct cyst.     

Étude en microscopie électronique et par cytophotométrie à balayage de la structure et de la distribution de la chromatine dans les noyaux des cellules cartilagineuses deTriturus cristatus âgés au cours de la régénération

Résumé Les cellules cartilagineuses des membres postérieurs deTriturus cristatus en régénération après amputation, ont été étudiées en microscopie électronique et par cytophotométrie à balayage. Nous nous sommes intéressés à la structure et à la distribution de la chromatine mais aussi à différents organites cytoplasmiques. Dans l'étude de cytophotométrie à balayage, la chromatine a été considérée à travers son constituant majeur, l'ADN, coloré par la réaction de Feulgen. Au cours de la régénération du membre, l'hétérochromatine initialement condensée, essentiellement accolée à la membrane nucléaire se décondense. Les vacuoles du cytoplasme, caractéristiques des animaux âgés par rapport aux animaux jeunes, disparaissent, les mitochondries et le reticulum endoplasmique rugueux deviennent plus abondants. Les caractéristiques nucléaires de l'activation cellulaire apparaissent précocement, précédent les modifications cytoplasmiques et conduisent à des cellules en tous points identiques aux cellules d'animaux jeunes en dehors de tout processus régénératif. Cette phase d'euchromatisation et de restructuration cytoplasmique est peut-être nécessaire à l'accroissement d'activité métabolique et à la division cellulaire qui suivent. Son déroulement peut expliquer tout au moins le ralentissement de la régénération observé chez les animaux âgés par rapport aux animaux jeunes.

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Electron microscopic and scanning cytophotometric study of chromatin structure and distribution in nuclei of cartilaginous cells of agedTriturus cristatus during regeneration

Summary Cartilaginous cells of aged newts (Triturus cristatus) were studied during hind limb regeneration. The electron microscope was used to study the structure and distribution of chromatin in the cell nuclei, while the DNA content of the chromatin was measured by means of a scanning cytophotometer.Changes in the ultrastructure of the cytoplasm during regeneration were also studied.It was observed that the structure and distribution of chromatin in the activated cell is greatly modified. In the non-activated cell of the aged newt, the chromatin is found highly condensed and distributed peripherally close to the nuclear membrane. In contrast, in the activated cells, the chromatin is much less condensed and is distributed throughout the nucleus. Moreover, cytoplasmic vacuoles, found only in the non-activated aged cells, disappear and an increase in the mitochondria and rough endoplasmic reticulum is also observed.Changes in the nuclear structure are observed prior to the cytoplasmic modifications.It is interesting to note that the process of activation induces structural changes in the aged cells which make these cells appear to be structurally identical to the young cells. This process of rejuvenation takes 3–5 days in the newt.We suggest that these structural changes of the chromatin and cytoplasm in the aged cells are necessary to increase the metabolic activity which precedes cell division. It may also explain why regeneration takes a longer time in the aged animals than in the young ones.

     

Les inhibiteurs de la phosphodiestérase de type 5 : une révolution dans le traitement des sympt?mes du bas appareil urinaire?

Context

The incidence of lower urinary tract symptoms (LUTS) related to benign prostatic hyperplasia (BPH) increases with age, affecting 50% of patients aged over 50 years and 90% of those aged over 80 years. The prevalence and severity of erectile dysfunction (ED) also increase with age. Its prevalence is estimated to be 31.6% in men over 40 years. LUTS as well as ED significantly affect the quality of life of patients and their partners. Several studies have shown that LUTS represent an independent risk factor for ED. The severity of LUTS is correlated with that of ED. The pathophysiological hypothesis linking LUTS to ED are an increase in sympathetic tone, alteration of NO/cGMP system, alteration of rho kinase system, and pelvic atherosclerosis.

Goal

Some treatments of LUTS have adverse effects on the erectile function. The phosphodiesterase type 5 inhibitors (IPDE 5) revolutionized the treatment of ED.

Material and methods

Several recent clinical studies evaluated the effect of daily treatment by IPDE 5 on LUTS secondary to BPH among patients with or without ED.

Results

This review shows that IPDE 5 administration improves LUTS significantly in 12 randomized clinical trials, as well as in both storage and voiding parts of the international prostate symptom score (IPSS) and in quality of life questionnaire. No adverse events were observed, and ED, which has a high prevalence among this population, was also improved.

Conclusion

The treatment of LUTS by IPDE 5 looks very promising, even though they are not yet approved for this indication in France.