PubMed Health⌕ Search

Biomedical subjects

F Martín

Publications and source records attributed to F Martín.

At least 19 recordsLinked to original sources
PubMed2002

Quantified 99mTc-MIBI scintigraphy for predicting chemotherapy response in breast cancer patients: factors that influence the level of 99m Tc-MIBI uptake.

The aim of this study was to establish whether tumour uptake of 99mTc-MIBI can predict response to chemotherapy in patients with breast carcinoma. Forty women suffering from breast carcinoma confirmed by tumour biopsy were studied prospectively. Fifteen patients subsequently underwent surgery and 25 were candidates for neoadjuvant chemotherapy. Breast scintigraphy was performed and planar and tomographic views (single photon emission computed tomography (SPECT)) were obtained after injection of 740 MBq of 99mTc-MIBI. The tumoural uptake was quantified by computer analysis. P-glycoprotein was evaluated by immunohistochemistry only in operable patients. The response to chemotherapy was evaluated at 3 months upon completion of treatment. The results of this study showed no relationship between 99mTc-MIBI uptake and the histological type or tumour size. There was an inverse correlation with the degree of tumour differentiation (P<0.05). 99mTc-MIBI uptake in negative P-glycoprotein lesions (2.36+/-1.72) was higher than in positive P-glycoprotein lesions (1.53+/-1.29), although the difference was not statistically significant. Lesions which responded to chemotherapy (16) showed higher 99mTc-MIBI uptake (7.70+/-5.20) than non-responding lesions (nine) (2.21+/-1.0) (P<0.001). In conclusion, there is a correlation between 99mTc-MIBI uptake in breast cancer and response to chemotherapy. Furthermore, 99mTc-MIBI uptake may be influenced by other factors such as the degree of tumour differentiation or tumour P-glycoprotein levels.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2002

Theory, abstraction and design in medical informatics.

OBJECTIVE: To analyze the scientific and engineering components of Medical Informatics. A clear characterization of these components should be undertaken to categorize different areas of Medical Informatics and create a research agenda for the future. METHODS: We have adapted a classical ACM and IEEE report on computing to analyze Medical Informatics from three different viewpoints: Theory, Abstraction, and Design. RESULTS: We suggest that Medical Informatics can be considered from these three perspectives: (1) Theory, from which medical informaticians formally characterize the properties of the objects of study, creating new theories or using and adapting existing theories (e.g., from mathematics), (2) Abstraction, from which medical informaticians deal with all aspects of medical information and create new abstractions, methods, and technology-independent models, which can be experimentally verified, and (3) Design, from which medical informaticians develop systems or act as information brokers or advisors between medical and technology professionals, to improve the quality of computer applications in medicine. CONCLUSION: Based on this framework, we suggest that Medical Informatics has an independent scientific character, different from other applied informatics areas. Finally, we analyze these three perspectives using data mining in medicine.

Medical Informatics↗
PubMed2002

[Ghost cell detection in vitreous cytology: clinico-pathological correlation].

PURPOSE: To determine the prevalence of detection of ghost cells (GCs) in vitreous hemorrhages (VHs) and correlate it with the development of ghost cell glaucoma. To compare our results with those previously reported. METHODS: Retrospective analysis of clinical records and vitreous cytology reports (cytospin and direct paraffin embedding) from patients undergoing vitrectomy for VH at Instituto Universitario de Oftalmobiología Aplicada and University Hospital, Valladolid, for the last 2 years. RESULTS: 76 VHs have been analysed; 45 corresponded to proliferative diabetic retinopathy and the remainder to several pathologies. GCs have been detected in 18 cases (25%) (4 out of 76 specimens were excluded): 14 were phakic and 4 pseudophakic. Most of 76 VHs lasted more than 2 months. No case of ghost cell glaucoma was detected, neither previously nor after vitrectomy. CONCLUSIONS: The frequency of detection of GCs in vitreous cytology may vary according to the cytologic technique. In contrast with the information previously reported, ghost cell glaucoma is an unfrequent disease, particularly after vitrectomy, probably because of a better removal of hemorrhagic debris from the vitreous cavity nowadays. Nevertheless, this diagnosis should not be overlooked.

Aqueous Humor↗
PubMed2001

Opposite effects of low and high doses of arginine on glutamate-induced nitric oxide formation in rat substantia nigra.

L-arginine is a very versatile amino acid that is involved in many important physiological processes such as protein, nitric oxide (NO), agmatine, putrescine, urea, L-ornithine or creatine synthesis and is essential for posttranslational arginylation of protein. The present study was designed to evaluate in vivo the effect of L-arginine on NO production in substantia nigra. In vivo spectroscopic and voltammetric studies were addressed in rats to record modifications in methemoglobin and NO levels under glutamate stimulation. Results showed that, under physiological L-arginine extracellular concentration, the intranigral infusion of glutamate produced an increase in NO levels. When a low dose of L-arginine was co-infused with glutamate, a persistent and higher increase in NO levels was observed. The co-infusion of glutamate with a moderate dose of L-arginine induced drastic and persistent NO production. It was also observed that high doses of either L-arginine or D-arginine inhibit NO production. Subsequently, these data show that L-arginine and D-arginine are involved in a mechanism that inhibits NO production.

Animals↗
PubMed2001

Soil pollution by oxidation of tailings from toxic spill of a pyrite mine.

On the 25th April 1998, toxic water and tailings from a pyrite mine of Aznalcóllar (southern Spain) spilled into the Agrio and Guadiamar River Basin affecting some 40 km2. In five sectors throughout the basin, we monitored the physical and chemical properties of the tailings as well as the degree of pollution in the soils on four different sampling dates: 5 May, 20 May, 4 June and 22 July 1998. The characteristics of the tailings deposited on the soils are shown to be related to distance from the spill. The oxidation rate of the tailings and the solubilization of the pollutant elements were more pronounced in the middle and lower sectors of the basin, where the particle size was finer, the sulfur content higher and the bulk density less. The increases in water-soluble sulfates, Zn. Cd and Cu were very rapid (the highest values being reached 25 days after the spill) and intense (reaching 45% of the total Cu, 65% of the total Zn and Cd). Meanwhile, the increases in water-soluble As, Bi, Sb, Pb and Tl were far lower (ranging between 0.002% of the total Tl and 2.5% of the total As) and less rapid in the case of As, Bi and Pb (the highest values for these elements being reached 40 days after the spill). These soluble elements infiltrated the soils with the rainwater, swiftly augmenting the soil pollution. Twenty-five days after the spill, when the rainfall ranged between 45 and 63 mm, the first 10-cm of the soils in the middle and lower sectors of the basin exceeded the maximum concentration permitted for agricultural soils in Zn, Cu and Tl. At 40 days after the spill, when the rainfall ranged between 60 and 89 mm, all the soils reached or exceeded the maximum permitted concentrations for As and Tl. Nevertheless, the pollutants tended to concentrate in the first 10 cm of the soils without seriously contaminating either the subsoil or the groundwaters. Consequently, a rapid removal of the tailings and the ploughing of the first 25-30 cm of the soils would be urgent measures to diminish pollutant concentration in the soils affected by the spill.

Environmental Monitoring↗
PubMed2001

From stem cells to beta cells: new strategies in cell therapy of diabetes mellitus.

Islet transplantation as a potential treatment for diabetes has been investigated extensively over the past 10 years. Such an approach, however, will always be limited mainly because it is difficult to obtain sufficiently large numbers of purified islets from cadaveric donors. One alternative to organ or tissue transplantation is to use a renewable source of cells. Stem cells are clonogenic cells capable of both self-renewal and multilineage differentiation. These cells have the potential to proliferate and differentiate into any type of cell and to be genetically modified in vitro, thus providing cells which can be isolated and used for transplantation. Recent studies have given well-defined differentiation protocols, which can be used to guide stem cells into specific cell lineages as neurons, cardiomyocytes and insulin-secreting cells. Moreover, these derived cells have been useful in different animal models. In this regard, insulin-secreting cells derived from R1 mouse embryonic stem cells restore blood glucose concentrations to normal when they are transplanted into streptozotocin-induced diabetic animals. These results show that diabetes could be among the first applications of stem cell therapy.

Animals↗
PubMed2001

Mutations affecting the cAMP transduction pathway modify olfaction in Drosophila.

The rutabaga and dunce genes, encode two enzymes of the cyclic adenosine monophosphate transduction pathway in Drosophila, adenylyl cyclase and cyclic adenosine monophosphate phosphodiesterase, respectively. Two main second messenger systems, depending on inositol 1,4,5-triphosphate and cyclic adenosine monophosphate, have been associated with olfaction in vertebrates as well as invertebrates. A relationship between the cyclic adenosine monophosphate signaling pathway and olfactory reception in Drosophila is suggested by the presence of cyclic nucleotide gated channels and cyclic-nucleotide modulated K+ channels in the antennae, the main olfactory organs. In this report, molecular, electrophysiological and behavioral data support the role of cyclic adenosine monophosphate in olfactory function for this species. Expression of both genes in the antennae has been shown by messenger ribonucleic acid analysis. Changes in the electroantennogram kinetics have been observed specifically on the slope of the initial rising phase, as predicted for processes that affect cyclic adenosine monophosphate concentration. Olfactory behavior changes due to both mutations were coherent with a functional meaning of the reported electrophysiological phenotype in olfactory perception. Sensitivity level increases or decreases for the mutants compared to the control line depending on the odorant. These results are compatible with some olfactory coding at the reception level by differential activation of a dual transduction system involving the inositol 1,4,5-triphosphate and cyclic adenosine monophosphate cascades.

Acetates↗
PubMed2001

[Functional neuroimaging in patients with rapid cycling bipolar depression].

Bipolar patients with a rapid cycling clinical course constitute an interesting sub-group for studies focused on the pathophysiology of the disorder, since several switches can be studied by the investigators in a short period of time. At present, functional neuroimaging techniques, as SPECT and PET, may be used for the neurobiological study of affective disorders. Few longitudinal functional neuroimaging studies assessing the different phases of bipolar disorder have been carried out. However, the published data suggest an asymmetrical temporal lobe dysfunction in depressive and manic phases of bipolar depression. Further studies with larger samples of patients are needed in order to improve our knowledge of the pathophysiology of bipolar disorder.

Bipolar Disorder↗
PubMed2001

Stem cells and diabetes.

Diabetes mellitus is a metabolic disorder affecting 2-5% of the population. Transplantation of isolated islets of Langerhans from donor pancreata could be a cure for diabetes; however, such an approach is limited by the scarcity of the transplantation material and the long-term side effects of immunosuppressive therapy. These problems may be overcome by using a renewable source of cells, such as islet cells derived from stem cells. Stem cells are defined as clonogenic cells capable of both self-renewal and multilineage differentiation. This mean that these cells can be expanded in vivo or in vitro and differentiated to produce the desired cell type. There exist several sources of stem cells that have been demonstrated to give rise to pluripotent cell lines: 1) embryonic stem cells; 2) embryonic germ cells; 3) embryonic carcinoma cells; and 4) adult stem cells. By using in vitro differentiation and selection protocols, embryonic stem cells can be guided into specific cell lineages and selected by applying genetic selection when a marker gene is expressed. Recently, differentiation and cell selection protocols have been used to generate embryonic stem cell-derived insulin-secreting cells that normalise blood glucose when transplanted into diabetic animals. Some recent reports suggest that functional plasticity of adult stem cells may be greater than expected. The use of adult stem cells will circumvent the ethical dilemma surrounding embryonic stem cells and will allow autotransplantation. These investigations have increased the expectations that cell therapy could be one of the solutions to diabetes.

Cell Differentiation↗
PubMed2001

Methodologies for estimating disaggregated anthropogenic emissions--application to a coastal Mediterranean region of Spain.

Regional estimates of both anthropogenic and biogenic emissions are important inputs for models of atmospheric chemistry. A disaggregated emissions inventory of all relevant pollutants for an area of 100 x 100 km2 centered in Burriana (Castellon, Spain) has been worked out. Time and spatial resolutions were hourly and 1 x 1 km2, respectively. Estimates were made for all relevant sources of anthropogenic emissions. The pollutants considered were SO2, NOx, NMVOCs (nonmethane volatile organic compounds), CH4, CO, CO2, N2O, and NH3. Thus, the emissions inventory includes up to 18 different NMVOCs. Emissions were computed for a typical sunny workday in June when strong photochemical activity could be expected. A "top-down" methodology was applied, taking as a starting point official annual and provincial estimates based on CORINAIR emission factors. This procedure is a very useful tool, particularly for those cases where a lack of sufficient local detailed information about the main emission-generating activities, such as road traffic, makes the use of a "bottom-up" approximation inadvisable. Moreover, updating these emission inventories is easier and they could be used to evaluate the impact of possible abatement strategies.

Air Pollutants↗
PubMed2001

Sentinel lymph node biopsy in breast cancer patients: subdermal versus peritumoural radiocolloid injection.

BACKGROUND AND AIMS: Sentinel lymph node (SLN) biopsy has been widely used in the management of melanoma and breast cancer. The aims of this study were (1) to compare the results obtained with the two main injection techniques, the peritumoural and subdermal; and (2) to determine the reliability of SLN to predict the regional lymph node status. METHOD: We prospectively studied 80 women (mean age 56 years) with breast cancer. Thirty-four of them were T1 and the remaining 46 were T2. Patients were divided into two groups. Group A, 36 patients were injected subdermally, surrounding the tumour site. Group B, 44 patients were injected peritumourally guided by ultrasound if non-palpable. Planar images were performed 15 min after the injection and continued until SLN identification. Before surgery, blue dye injection was administered similarly to the radiocolloid. After incision, a hand-held gamma probe was used to reach the SLN. All nodes harvested were analysed by classic pathology techniques. RESULTS: Overall, lymphoscintigraphy allowed the detection of SLN in 75/80 patients (94%). All subdermal lymphoscintigraphies were positive (36/36) compared with 89% of peritumoural (39/44). Blue dye detected SLN in 23/31 patients (74%) after subdermal injection and in 24/34 patients (71%) after peritumoural injection. The sensitivity to localize the SLN with lymphoscintigraphy+blue dye+gamma probe was 92% (33/36) within the subdermal group and 91% (40/44) within the peritumoural group. Overall, five false negative SLN were found. All of these corresponded to T2 tumours with a size greater than 2.5 cm. The negative predictive value and the accuracy were 93% and 94%, respectively, for the subdermal group and 90% and 93% for the peritumoural group. CONCLUSIONS: (1) Our results indicate that both techniques have similar results. However, we suggest that T2 tumours with a size greater than 2.5 cm should be excluded from the SLN technique, in order to improve the accuracy and negative predictive value. (2) Lymphoscintigraphy is essential for visualizing the SLN, and blue dye can be helpful when the gamma probe does not localize the SLN.

Adult↗