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F Domínguez

Publications and source records attributed to F Domínguez.

At least 37 records · Page 2Linked to original sources
PubMed1998

Prothymosin alpha stimulates Ca2+-dependent phosphorylation of elongation factor 2 in cellular extracts.

Prothymosin alpha (PTA) stimulates in a dose-dependent manner the phosphorylation of a 105-kDa protein (p105) in cell extracts from different cell types. Protein sequencing and immunological analysis indicated that this protein is elongation factor 2 (EF-2). We propose that calcium/calmodulin-dependent protein kinase III is responsible for the PTA-dependent EF-2 phosphorylation based on the following lines of evidence: (a) Ca2+ is required for the effect; (b) calmodulin enhances the reaction, and calmodulin inhibitors block the phosphorylation; and (c) no phosphorylation is seen in cell extracts depleted of calmodulin-binding proteins. To obtain a strong phosphorylated EF-2 band, we found it necessary to add PTA to cytosolic extracts from synchronized dividing cells in various phases of the cell cycle except in mitosis. Since PTA is a nuclear protein everywhere in the cell cycle except in mitosis, when it is found in the cytoplasm, we hypothesize that, if PTA activates EF-2 phosphorylation in vivo, as present data suggest, its presence in the cytoplasm during mitosis could explain why EF-2 phosphorylation is mainly restricted to that phase of the cell cycle. Moreover, other bands in addition to EF-2 were phosphorylated in a calmodulin- and PTA-dependent manner, and several of them (in a range between 50 and 60 kDa) have similar Mr to those that conform to the holoenzyme calcium/calmodulin dependent protein kinase II, suggesting that PTA could have a more general function modulating the activity of various Ca2+/CaM-dependent enzymes along the cell cycle.

3T3 Cells↗
PubMed1998

A c-myc antisense oligonucleotide inhibits human retinal pigment epithelial cell proliferation.

The purpose of this work was to investigate if MYC-dependent intracellular mitogenic pathway is active in cultures of human retinal pigment epithelial (hRPE) cells and whether myc antisense phosphorotioate oligonucleotides (c-myc-AS-ODN) are useful tools for inhibiting the proliferation of hRPE cells. Cultures of hRPE cells were established from adult human corneal donors. These cells were positively stained for cytokeratins and vimentin. Myc mRNA expression was determined by Northern blot analysis and it was determined by means of immunofluorescence if MYC was expressed. C-myc-AS-ODN effect on cell proliferation was estimated by evaluating the incorporation of 5-bromo-2'-deoxy-uridine into cellular DNA. Cell number was estimated by using a tetrazolium bromide based colorimetric method. Human RPE cells in culture expressed MYC and myc mRNA as well as prothymosin alpha mRNA--a gene whose transcription is under MYC control--indicating that MYC-dependent intracellular mitogenic pathway is active in these cells. In accordance with this, we found that blocking the expression of myc by the addition of c-myc-AS-ODN to the culture medium inhibited hRPE cell proliferation. The effect of the c-myc-AS-ODN was found to be sequence specific (the use of a control oligonucleotide with the same sequence but in an opposite direction had no effect) and dose-dependent (4 microM was the lowest effective dose tested). By using RT-PCR we found that the c-myc-AS-ODN inhibition of cell proliferation was related to a diminution in c-myc mRNA expression, and by immunofluorescence we detected a diminution in c-MYC protein staining in RPE cells after 48 hr of treatment with c-myc-AS-ODN. Furthermore, growth inhibition remained for at least 5 days after addition of a single dose of the c-myc-AS-ODN to the culture. We conclude that hRPE cell proliferation is under MYC control. Blocking the expression of myc by c-myc-AS-ODN inhibited hRPE cell proliferation. These findings establish a rationale for investigating the potential use of a c-myc-AS-ODN as a novel therapeutical tool in the treatment of Proliferative Vitreoretinopathy.

Adult↗
PubMed1998

TGF-beta1 actions on FRTL-5 cells provide a model for the physiological regulation of thyroid growth.

Little is known about the TGF-beta1 mechanism that promotes thyroid cell growth arrest. We assessed TGF-beta1 effects on Fisher rat thyroid cell line (FRTL-5). This allowed us to study TGF-beta1 action on thyroid cells in various physiological situations such as actively proliferating cells, resting cells stimulated to proliferate by the action of various mitogens, and resting cells. TGF-beta1 arrested proliferating FRTL-5 cells, increasing c-myc mRNA levels and reducing p27-free cyclin D1 protein levels, without affecting either the cellular content of p27 or the cyclin D1-p27 complexes. Moreover, TGF-beta1 treatment reduced the activity of cyclin E-CDK2 complexes and, consequently, pRB was found to be hypophosphorylated. TGF-beta1 prevented resting cells to enter in the cell cycle when stimulated with growing medium (newborn calf serum plus a mixture of five hormones) but not when TSH (thyroid stimulating hormone) plus IGF-1 (Insulin-like growth factor I) were used as mitogens. Both stimuli increased the levels of cyclins D1, D3 and E but TGF-beta1 had a greater effect in decreasing these cyclin levels in growing-medium stimulated cells than in TSH + IGF-1. This suggests that for FRTL-5 cells, the content of these cyclins must exceed a threshold to progress through the cell cycle. TGF-beta1 induced apoptosis in quiescent cells, accompanied by a reduction in p27 protein levels and an increase in c-myc expression. Interestingly, TGF-beta1-induced variations in prothymosin alpha and c-myc mRNA levels were not correlated. TGF-beta1 always promoted an increase of p15 mRNA levels. In summary, our results point to the fact that TGF-beta1 could play a physiological role in the control of thyroid growth through the modification of cell cycle regulatory proteins.

Animals↗
PubMed1998

[Metanephric adenoma. A new embryonal tumor of the kidney].

Metanephric adenoma is a kidney tumour first identified in 1988 and classified within the group of nephroblastic tumours. It is described as a benign tumour with no capacity to become malignant or metastatic, predominant in women in a 2:1 ratio relative to men, and which can develop at any point in life. In most cases, it is incidentally found as a result of an abdominal ultrasound study for signs and symptoms unrelated to the kidney. Less commonly it presents with pain, polycythemia, haematuria or palpable mass. The key radiologic sign is calcification, which occurs in a statistically higher proportion than in any other renal neoplasia. From the pathoanatomical point of view, the tumour consists of small acinus separated by acellular stroma resembling the hamartomatous elements of nephroblastomatosis and Wilms' tumour. This paper contributes one case of metanephric adenoma, the first one in the national literature.

Adenoma↗
PubMed1998

[Extracorporeal membrane oxygenation in myocardial failure after pediatric heart surgery].

In spite of progressive improvement not only in myocardial protection but also in anesthetic and surgical techniques, the repair of complex congenital heart defects can still lead to cardiopulmonary compromise refractory to conventional treatment. We describe two patients in whom successful surgical repair of congenital heart defects was followed by severe heart failure refractory to medical treatment. Both patients were managed by extracorporeal membrane oxygenation (ECMO). We discuss the indications, contraindications and use of ECMO in the postoperative intensive care unit.

Bioprosthesis↗
PubMed1997

[Glucose metabolism in children undergoing extracorporeal circulation: its correlation with weight and the degree of hypothermia].

INTRODUCTION: A prospective study has been carried out in 33 children with congenital heart disease, aged 5 days to 16 years, operated on with the aid of cardiopulmonary bypass (CPB), in order to evaluate intra and postoperative glycemia in relation to children's weight and intra-CPB perfusion temperature. MATERIAL AND METHODS: Plasmatic levels of glucose, lactate, insulin, C-peptide, growth hormone (GH) and cortisol were measured at five different times, from pre-CPB up to 18 hours post-CPB. Thirteen children weighing less than 10 kilograms (group I) were compared to 20 children weighing more than 10 kilograms (group II), and 15 children operated on with perfusion temperature below 27 degrees C (group A) were compared to 18 with perfusion temperature above 27 degrees C. RESULTS: All the cases showed intraoperative hyperglycemia. In relation to weight, evolution of glycemia was similar in both groups but anaerobic glycolysis was significantly higher in group I. In relation to temperature, glycemia, lactic acidemia intra- and post-CPB and serum C-peptide post-CPB were significantly higher in group A. Intraoperative insulin was decreased and GH serum levels were also higher in group I and A, but fell drastically post-CPB in all groups. CONCLUSIONS: Perioperative control of glycemia is important in children operated on with the aid of CPB. Control of lactic acidemia is also expedient. Carbohydrates metabolism and its hormonal regulation are more disturbed in infants and in children operated on with low perfusion temperature.

Adolescent↗
PubMed1997

Development of ELISA to estimate thymosin alpha1, the N terminus of prothymosin alpha, in human tumors.

We reported that tumor content of prothymosin alpha (ProT alpha) is a proliferation index of human breast tumors that might be used to identify patients at high risk for distant metastasis (Dominguez et al., Eur J Cancer 1993; 29A:893-7). In that study ProT alpha concentrations were measured by a RIA; here we present an alternative nonisotopic assay that could be used in a standard clinical laboratory. Main features of the ELISA are: (a) A recombinant fusion protein glutathione S-transferase (GST)-human ProT alpha was used to coat the microtiter plates; (b) we used a polyclonal antiserum raised in rabbits that detects thymosin alpha1, the NH2-terminal fragment of ProT alpha; (c) it is as sensitive as the RIA; (d) it is faster than the RIA. ProT alpha concentrations in various human tumors (skin, esophagus, colorectal, and breast) as assessed by ELISA were comparable with, although twofold greater than, the values previously estimated by RIA.

Antibody Specificity↗
PubMed1997

[Diagnostic difficulties in the narcolepsy-catalepsy syndrome: with reference to our series of cases].

The narcolepsy-cataplexy syndrome is a disorder of unknown aetiology, characterized by excessive daytime sleepiness associated with cataplexy and other REM sleep phenomena. Diagnosis is based on the clinical findings, although this may be difficult especially with respect to confirming the cataplexy. Objective tests, such as typing for HLA, DR2DQ1 (DRw15DQw6, WHO90) and above all TMLS (average latency < 5 mn and two or more onsets of sleep in the phases REM and SOREMP's) is of great help. However, the exact diagnostic significance of some aspects of these tests and their parameters is still under discussion. In this paper we review our series of cases consisting of fourteen patients who fulfil the clinical diagnostic criteria required in the ICSD-1990. TMLS and HLA typing was done for all. Of the HLA types, DQ1 was present in all our patients, unlike DR2 which was not found in two patients. Regarding TMLS, the average latency < 5 mn is a parameter met by all cases, although one did not have SOREMP's. The findings of the objective tests done on our patients are in agreement with those described by other authors. They underline the significance of the support they lend to the diagnosis. However, they are not the definite answer to the problem.

Adult↗
PubMed1997

[The role of the stent in non-coronary cardiopathies].

INTRODUCTION: The stent has demonstrated to be a useful device in the prevention of postangioplasty coronary restenosis and it is expected to have a favourable effect as an alternative or complementary treatment of stenotic lesions in arteries or veins associated with congenital defects. The aim of this study is to analyze our experience in this setting. MATERIAL AND METHODS: From February 1992 to March 1996, 28 stenting procedures were performed in 26 patients (mean age: 8.6 +/- 0.7 years; mean weight: 26.2 +/- 3 kg). In 12 patients, stenting was single, and a iliac Palmaz stents were always used. Stenting location was: pulmonary artery branches in 17 patients, right ventricular outflow in 2 patients, in the junction of right atrium with pulmonary artery in 2 patients, systemic veins in 2 patients and in post Mustard intratrial channel stenosis in 2 patients. 25 patients had previously undergone at least one surgical procedure. RESULTS: The stenotic diameter of the treated lesions increased significantly after the procedure (4.4 +/- 0.3 mm before stenting vs 11.6 +/- 0.3 mm after stenting, p < 0.0001) and the transtenotic gradient decreased from 38.1 +/- 5 to 12 +/- 3.8 mmHg. Those changes were associated with a diminution of right ventricular pressure (81.6 +/- 3 vs 56.7 +/- 6 mmHg, p < 0.0001) in patients with pulmonary branch stenosis without septal defects. There was no mortality among the percutaneously treated patients and only one patient needed surgery. Nevertheless, one patient died after bilateral intraoperative stenting. CONCLUSION: The treatment of proximal or distal stenotic lesions in the pulmonary tree, systemic veins, and obstructed intraatrial channels with stents, can replace or complement conventional balloon angioplasty. It also offers a useful and effective alternative to surgery, when it is impossible or carries a risk.

Adolescent↗
PubMed1996

Assessment and accreditation of Mexican medical schools.

With the objective of evaluating and accrediting the quality of medical education in the country, the Mexican Association of Medical Schools initiated the National Programme for the Strengthening of the Quality of Medical Education (PNFCE). This programme led to the establishment of the National System of Accreditation. Medical school deans in Mexico determined the criteria for the evaluation of quality and its subsequent standards through a consensus process. The following 10 criteria resulted: general basis and educational objectives; government and institutional orientation; educational programme and academic structure; educational process assessment; students; teaching staff; institutional coherence; resources; clinical sites; and administration. Eighty-eight standards were developed in the instrument designed for the self-evaluation phase. The information resulting from the self-evaluation will be verified by a group of experts during a survey visit, which will be finalized with a report to serve as the basis for the decision to be made by the Accreditation Commission. The self-evaluation phase started in 1994. In 1996 four schools submitted their request for accreditation. As of July 1996, one survey visit has been completed and three more are programmed for the second half of the year.

Accreditation↗
PubMed1996

[PSA and hormone-refractory period in prostatic cancer].

Study of the characteristics of the hormone-refractory period in 32 patients with disseminated prostate cancer who had achieved a complete response to total androgen suppression, appreciating in all of them a subclinical or asymptomatic stage and a clinical or symptomatic one. The subclinical stage was characterized by raised PSA levels and ranged between 3-35 months; at 12 months 59% of patients had advanced to the symptomatic stage, while at 24 months this percentage is 84%. The clinical stage extends from appearance of symptoms to the patient's death, ranging from 3 to 32 months; at 12 months 41% has died; and 91% at 2 years.

Adenocarcinoma↗
PubMed1996

Evidence for the involvement of non-androgenic testicular factors in the regulation of hypothalamic somatostatin and GHRH mRNA levels.

The growth hormone (GH) secretory pattern is dependent on sex and developmental stage. It is generally accepted that in the male rat this pattern is markedly influenced by androgens secreted by the Leydig cells. Recent findings, however, point to the existence of other non-androgenic testicular factors produced by the Sertoli cells and which regulate in vivo the GH responses to growth hormone releasing hormone (GHRH). The aim of this work was to investigate the role played by non-androgenic testicular factors on hypothalamic somatostatin (SST) and GHRH mRNA levels. Seventy-day-old male Sprague-Dawley rats were used throughout the work. They were divided into five groups: (1) control rats; (2) gonadectomized rats; (3) gonadectomized rats supplemented with exogenous administration of dihydrotestosterone (DHT); (4) ethylene dimethane sulphonate (EDS)-treated rats; (5) EDS-treated rats supplemented with exogenous administration of DHT. EDS is a cytotoxic agent that specifically destroys the Leydig cells. The rats were killed after 15 days of treatment. Hypothalamic SST mRNA levels were determined by Northern blot and by in situ hybridization, and GHRH mRNA levels assessed by Northern blot. We found that selective removal of Leydig cells with EDS greatly reduced the SST mRNA content in the periventricular nucleus of the hypothalamus. These levels were significantly lower than those found in gonadectomized rats. Furthermore, replacement treatment with dihydrotesterone (DHT) did not completely restore SST mRNA levels in EDS-treated rats, contrasting with the complete recovery of SST mRNA levels in gonadectomized rats. On the other hand, gonadectomy and EDS treatment produced a significant reduction in GHRH mRNA levels. DHT administration reversed the action of gonadectomy, but did not restore GHRH mRNA content in EDS-treated rats. These data suggest that, in addition to testosterone, as yet unidentified non-androgenic testicular factors can significantly influence SST and GHRH mRNA levels. This may indicate that non-androgenic testicular factors acting at hypothalamic level may be important in the neuroregulation of GH secretion and in the maintenance of sexual dimorphism in GH secretory pattern.

Animals↗
PubMed1996

[Wünderlich syndrome caused by metastatic gastric sarcoma in the kidney. Report of a case].

Contribution of one case of Wünderlich Syndrome secondary to a simple metastasis to the right kidney from a gastric sarcoma operated three years earlier. Pain, palpable mass on the side and decreased haematocrit were the primary symptoms. Diagnosis was confirmed by Computerized Axial Tomography. The therapeutical approach was radical nephrectomy. At 5 years, this female patient remains alive showing no evidence of tumoral disease in the follow-up controls performed.

Aged↗
PubMed1995

[Celiac disease with occipital calcifications: 2 late cases].

The association of celiac disease, epilepsy and occipital calcifications with initial clinical manifestations of epilepsy during the first two decades of life with an often progressive and variable course and clinical expression of malabsorption has recently been described. Two cases of celiac disease with occipital calcifications and a presentation with neurologic symptoms in adulthood are reported. The first case is that of a 40-year-old male who presented recurrent and alternating pure brachial monoparesis and later acute abdominal pain following which celiac sprue was diagnosed. The second case is that of a 53-year-old woman diagnosed with celiac sprue 20 years before, presenting permanent myoclonus in the lower limbs which were progressive in severity, ataxic march and generalized tonoclonic seizures. Both patients had bilateral occipital calcifications on CT and celiac disease was demonstrated on biopsy. The first case also showed marked signal alteration in the white matter on MRI. Celiac disease with cerebral calcifications presents also in adulthood with atypical clinical manifestations. Suspicion of celiac disease may be confirmed by non-invasive methods such as antigliadin and antiendomysium antibody determination. CT imaging is characteristic.

Adult↗
PubMed1995

Regulation of thymosin beta 4 mRNA levels during cell proliferation.

The levels of thymosin beta 4 mRNA were studied throughout the cell cycle of NIH 3T3 cells. In serum deprived, quiescent cells, the levels of thymosin beta 4 were undetectable; after serum restoration, the cells were induced to proliferate and we found a pronounced increase in thymosin beta 4 mRNA levels at the G1/S transition. Thymosin beta 4 mRNA was induced even in the presence of cycloheximide. On the other hand, cycling cells that were synchronized at different stages of the cycle by means of mitotic shake-off after nocodazole arrest or a double thymidine block did not show any variation in the levels of thymosin beta 4 mRNA when they progressed synchronously through the cycle. In conclusion, the present data indicate that the thymosin beta 4 gene is regulated by cell proliferation but it is not a cell cycle-regulated gene. Finally, we studied thymosin beta 4 mRNA stability by inhibiting thymosin beta 4 gene transcription with actinomycin D. Our results suggest that thymosin beta 4 mRNA has a pronounced stability, a fact that might be relevant to account for the presence of thymosin beta 4 in enucleated cells like platelets.

Animals↗
PubMed1995

[Aortic prosthetic endocarditis and periprosthetic abscess caused by Staphylococcus aureus].

Prosthetic endocarditis with annular abscess formation is a severe complication of cardiac valve replacement fortunately uncommon, though highly lethal. Increasing surgical experience and the high mortality with medical management have led to a widespread recommendation for early prosthetic replacement. We report a case of a 49 year old man with infective endocarditis due to Staphylococcus aureus in aortic ascendens prosthetic and aortic valve prosthetic complicated with periaortic abscess which was as successful treatment by drain of abscess without prosthetic replacement.

Abscess↗