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Biomedical subjects

M Puente

Publications and source records attributed to M Puente.

At least 19 recordsLinked to original sources

[Efficacy of postoperative radiation therapy for squamous cell carcinoma of the head and neck: results of a prospective randomised clinical trial].

INTRODUCTION: A prospective randomised clinical trial was designed to assess the usefulness of postoperative radiotherapy (RT) in terms of loco-regional control and survival in patients with surgically treated advanced (stages III to IV) head and neck squamous cell carcinoma with negative margins and without extracapsular extension in positive neck nodes. MATERIALS AND METHODS: Between 1994 and 1995, 51 patients were included in the study and 42 were considered evaluables (from which 21 received postoperative RT). A minimum follow-up of 3 years was required. RESULTS: The loco-regional recurrence rates were identical in irradiated and non-irradiated patients (15/21 cases--70%--in each group), as was the 5-year disease-specific survival (35% for both groups). The only parameter that was associated with a reduced disease-specific survival was the presence of regional lymph node metastases. CONCLUSION: Our results suggest that postoperative RT does not increase loco-regional control or survival in patients with completely resected advanced head and neck squamous cell carcinoma.

Carcinoma, Squamous Cell↗

Dentoalveolar stress from bodily tooth movement at different levels of bone loss.

This study was undertaken to determine the stress that appears in the tooth, the periodontal ligament, and the alveolar bone, when a couple and horizontal forces were applied to obtain the bodily movement of a lower digitalized canine and its changes depending on the degree of loss of the supporting bone. The analysis of tensions was carried out by means of the finite element method (FEM) with no bone loss and after reducing the support bone 2, 4, 6, and 8 mm. False color three-dimensional images indicating intensity of stress (tensile and compressive) and extension are generated. After the application of the forces in the model without bone loss, a rather uniform distribution of stress is observed. When the bone loss is 2 mm, an increased stress in the levels next to the alveolar crest is already apparent. After 4, 6, and 8 mm of bone support reduction, a change of the sign and an increment of the magnitude of stress in the lowest levels occurs.

Alveolar Bone Loss↗

[Alpha tumor necrosis factor in central nervous system disease associated with HIV infection].

The aim of the present study is to evaluate the relationship between the alpha tumor necrosis factor (TNF-alpha), interleukin 1 beta (IL-1 beta) and the neurological disease associated to the HIV-1 infection and different neurological manifestations (15 infections of the CNS and 11 AIDS-dementia complexes) and 14 from a control group. The mean value of TNF-alpha in CSF of patients with HIV-1 infection and AIDS-dementia complex was 19.8 +/- 30.6 pg/ml, superior to that of the control group (p < 0.05). The group of patients with HIV-1 and opportunistic CNS infection has a TNF-alpha value of 28.5 +/- 37.8 pg/ml, that is superior to that of the patients with the AIDS-dementia complex (TNF-alpha = 7.9 +/- 9.4 pg ml; p < 0.05). Within the group of patients with a CNS infection, the value of TNF-alpha was greater in those in the acute phase (44.2 +/- 42.4 pg/ml) than in those in the chronic phase (6.8 +/- 7.6 pg/ml; p < 0.05). The TNF-alpha in the CSF is a good marker of infection of the CNS in the HIV-1 infection.

AIDS Dementia Complex↗

Epidermal growth factor receptors in human breast and endometrial carcinomas.

The incidence and levels of epidermal growth factor receptor (EGFR) were studied in 67 breast tumors and 22 endometrial carcinomas. Estrogen receptors (ER) were also measured in all samples and progesterone receptors (PR) were analyzed in 57 breast samples and 21 endometrial tumors. A high level of EGFR expression is found in both breast and endometrial carcinomas, although the incidence of EGFR content is greater in breast carcinomas. 36% of breast tumors had EGFR at levels 3-49.5 fmol/mg membrane protein, whereas this percentage of positivity was 27% for endometrial tumors. In 51% of breast carcinoma and 73% of endometrial tumors, there was a positive ER content, whereas 53% of breast tumors and 62% of endometrial carcinomas were positive. A clear inverse relationship between EGFR content and ER and PR status has been observed in breast tumors. Our data confirm the previously described inverse correlation between expression of EGFR and estrogen receptors in human breast cancer. We also show here that there is a similar inverse relationship between EGFR content and ER levels in endometrial tumors.

Biomarkers, Tumor↗

Role of an estrogen receptor-dependent mechanism in the regulation of estrogen receptor mRNA in MCF-7 cells.

We have previously demonstrated that regulation of estrogen receptor (ER) expression in MCF-7 breast cancer cells is a complex process involving transcriptional and posttranscriptional regulation by estradiol. Treatment of MCF-7 cells with estradiol results in the down-regulation of receptor expression; posttranscriptional suppression of receptor mRNA appears to be the predominant mechanism. To determine whether posttranscriptional regulation of ER gene expression is mediated by an ER-dependent mechanism independent of protein synthesis, we have used the competitive estrogen antagonist, 4-hydroxytamoxifen, and the inhibitor of protein synthesis, cycloheximide, to study regulation of ER mRNA by estradiol. 4-Hydroxytamoxifen had no effect on the steady-state level of receptor mRNA and effectively blocked the suppression of ER mRNA by estradiol. The metabolic inhibitor, cycloheximide, was unable to prevent the estrogen induced decrease in ER mRNA. These data provide evidence that the posttranscriptional suppression of ER expression through estradiol is mediated through the ER independent of protein synthesis. A study of the effects of estradiol on the steady-state levels of nuclear and cytoplasmic receptor mRNA suggest that posttranscriptional suppression is a nuclear event.

Breast Neoplasms↗

Regulation of the estrogen receptor in MCF-7 cells by estradiol.

The role of estradiol in the regulation of its cognate receptor in MCF-7 cells was investigated in this study. After treatment with 10(-9) M estradiol, the level of receptor protein was measured using an enzymeimmunoassay. By 6 h, the receptor protein declined by about 60% from a level of approximately 3.6 to 1.2 fmol/micrograms DNA. The level of receptor remained suppressed for 24-48 h. Similar results were obtained with an estrogen receptor (ER) binding assay. The steady state level of ER mRNA was determined by an RNase protection assay. Estrogen treatment resulted in a maximum suppression of mRNA by 6 h. Receptor mRNA remained depressed for 48 h. Transcription run on experiments demonstrated a transient decrease of about 90% in ER transcription after 1 h. By 3-6 h transcription increased approximately 2-fold and remained elevated for at least 48 h. These data suggest that estrogen down-regulates ER mRNA by inhibition of ER gene transcription at early times and by a posttranscriptional effect on receptor mRNA at later times.

Breast Neoplasms↗

Inhibition of pituitary-gonadal function in male rats by a potent GnRH antagonist.

The inhibitory effects of the potent GnRH antagonist, [Ac-D-pCl-Phe1,2,D-Trp3,D-Arg6,DAla10]GnRH (GnRHant) upon pituitary-gonadal function were investigated in normal and castrated male rats. The antagonist was given a single subcutaneous (s.c.) injections of 1-500 micrograms to 40-60 day old rats which were killed from 1 to 7 days later for assay of pituitary GnRH receptors, gonadal receptors for LH, FSH, and PRL, and plasma gonadotropins, PRL, and testosterone (T). In intact rats treated with low doses of the antagonist (1, 5 or 10 micrograms), available pituitary GnRH receptors were reduced to 40, 30 and 15% of the control values, respectively, with no change in serum gonadotropin, PRL, and T levels. Higher antagonist doses (50, 100 or 500 micrograms) caused more marked decreases in free GnRH receptors, to 8, 4 and 1% of the control values, which were accompanied by dose-related reductions in serum LH and T concentrations. After the highest dose of GnRHant (500 micrograms), serum LH and T levels were completely suppressed at 24 h, and serum levels of the GnRH antagonist were detectable for up to 3 days by radioimmunoassay. The 500 micrograms dose of GnRHant also reduced testicular LH and PRL receptors by 30 and 50% respectively, at 24 h; by 72 h, PRL receptors and LH receptors were still slightly below control values. In castrate rats, treatment with GnRHant reduced pituitary GnRH receptors by 90% and suppressed serum LH and FSH to hypophysectomized levels. Such responses in castrate animals were observed following injection of relatively low doses of GnRHant (100 micrograms), after which the antagonist was detectable in serum for up to 24 h. These data suggest that extensive or complete occupancy of the pituitary receptor population by a GnRH antagonist is necessary to reduce plasma gonadotropin and testosterone levels in intact rats. In castrate animals, partial occupancy of the available GnRH receptor sites appears to be sufficient to inhibit the elevated rate of gonadotropin secretion.

Animals↗

[Precocious puberty associated with Von Recklinghausen's disease. Developmental follow-up under cyproterone acetate treatment].

Authors describe a case of a boy aged 8-10/12 years with precocious puberty associated with Von Recklinghausen's disease. He was treated with cyproterone acetate (100 mg/m2/24 h oral doses) and controlled for a period of two years. He shows very few effects of puberal physical signs and improvement of his sexual behavioral area. They have evaluated growth evolution by different parameters and couldn't appreciate any improvement because of the advanced bone age (13-6/12 years) when treatment was started.

Adult↗