PubMed · 12097462
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
Secondo Lastoria, Sergio Piccolo, Pietro Muto. 2002. Invited commentary: one step forward.. https://pubmed.ncbi.nlm.nih.gov/12097462/
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
We introduce a modified Tikhonov regularization method to include three-dimensional x-ray mammography as a prior in the diffuse optical tomography reconstruction. With simulations we show that the optical image reconstruction resolution and contrast are improved by implementing this x-ray-guided spatial constraint. We suggest an approach to find the optimal regularization parameters. The presented preliminary clinical result indicates the utility of the method.
OBJECTIVE: To evaluate the incidence of breast symptoms in a population treated with various hormone replacement therapy (HRT) regimens and to detect the variations in breast symptomatology after HRT changing to tibolone administration. METHODS: This prospective placebo-controlled clinical trial was conducted on healthy women on HRT reporting breast symptoms. A questionnaire was given to each woman to detect breast symptomatology. Breast tenderness and mastalgia were evaluated using a visual analogue scale (VAS). According to the choice of the each woman with breast symptoms, the HRT was changed to tibolone (2.5 mg/day per os) or to calcium carbonate (1 tab/day, placebo group). The duration of treatment was of 12 months. After 6 and 12 months breast symptomatology was re-evaluated. RESULTS: Among the 600 screened women, 64 (10.7%) were suffering from breast symptomatology. After 6 and 12 months of treatment with tibolone or placebo, mean VAS score for breast tenderness and for mastalgia resulted significantly (P<0.05) decreased, without differences between groups, in comparison with basal value. Only one woman had no improvement from the breast symptoms with tibolone administration. CONCLUSIONS: Shifting from classical HRT to tibolone is followed by a significant reduction of breast symptomatology in postmenopausal women with breast complaints similar to that obtained with treatment withdrawal.
Telomere erosion and subsequent dysfunction limits the proliferation of normal human cells by a process termed replicative senescence. Replicative senescence is thought to suppress tumorigenesis by establishing an essentially irreversible growth arrest that requires activities of the p53 and pRB tumor suppressor proteins. We show that, depending on expression of the pRB regulator p16, replicative senescence is not necessarily irreversible. We used lentiviruses to express specific viral and cellular proteins in senescent human fibroblasts and mammary epithelial cells. Expression of telomerase did not reverse the senescence arrest. However, cells with low levels of p16 at senescence resumed robust growth upon p53 inactivation, and limited growth upon expression of oncogenic RAS. In contrast, cells with high levels of p16 at senescence failed to proliferate upon p53 inactivation or RAS expression, although they re-entered the cell cycle without growth after pRB inactivation. Our results indicate that the senescence response to telomere dysfunction is reversible and is maintained primarily by p53. However, p16 provides a dominant second barrier to the unlimited growth of human cells.