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Biomedical subjects

A Ramírez

Publications and source records attributed to A Ramírez.

At least 19 recordsLinked to original sources

Structure of the human CD94 C-type lectin gene.

The genomic structure of the human CD94 gene was obtained by analyzing genomic clones obtained from two different libraries. The CD94 gene contains six exons separated by five introns. The carbohydrate-recognition domain (CRD) is encoded by three exons, and the conservation of intron positions within the CRD indicated that CD94 is closely related to group V of C-type lectins. Primer extension and S1 nuclease protection assays showed that initiation of transcription in the CD94 gene is heterogeneous, but restricted to a 60 base pair region around the major initiation site enclosed within a putative initiator element (TTA+1TTCA). The study of the promoter region of CD94 may help to understand the selective expression of this C-type lectin glycoprotein on NK cells and subsets of cytotoxic T cells.

Antigens, CD

The genomic fingerprinting of the coding region of the beta-tubulin gene in Leishmania identification.

We have demonstrated the polymorphism of the beta-tubulin gene region in Leishmania and its value in the identification of the parasite. In this work we have shown that the coding region of the gene has sufficient variation to accurately discriminate these parasites at the subgenus level. Nevertheless, intrasubgenus diversity, for particular restriction enzymes, was found in New World Leishmania belonging to the Leishmania subgenus. For instance, differences were found between mexicana and amazonensis strains. A unique pattern at the species level was found in particular species of both subgenera, e.g. L. (L.) major strain P and L. (L.) tropica belonging to the Leishmania subgenus, and L. (V.) panamensis strain LS94 from the Viannia subgenus. Particular endonucleases are diagnostic in Leishmania species discrimination as in the case of PvuII for the mexicana and amazonensis. This variation evidenced in the beta-tubulin gene region of Leishmania also occurred in other Kinetoplastida e.g. Trypanosoma cruzi, Leptomonas spp. and Crithidia spp. Moreover, these organisms showed a different genomic fingerprinting for the beta-tubulin gene among them and also Leishmania. Thus, the polymorphism of the coding region of the beta-tubulin gene can be used as a molecular marker for the identification of Leishmania.

Animals

[Mobile thrombus in the right cardiac cavities in patients with severe pulmonary thromboembolism. Importance of echocardiography].

The pulmonary thromboembolism is a frequent and severe disease, usually difficult to recognize, specially in patients with thrombotic material trapped within right heart cavities. We present our experience in three patients with severe pulmonary thromboembolism where echocardiographic study demonstrated the presence of huge mobile thrombus in right heart cavities, which demanded urgent therapy with excellent results. We would like to stress that echocardiographic study in these patients could be elective diagnostic procedure, avoiding the realization of pulmonary arteriography, which could bring risk of possible thrombus mobilization.

Adult

Analysis of sequences controlling tissue-specific and hyperproliferation-related keratin 6 gene expression in transgenic mice.

Keratin 6 (K6) is an intermediate filament protein found in hair follicles and in several internal stratified epithelia. This keratin has been the focus of special attention because it is also strongly induced in epidermal interfollicular keratinocytes in hyperproliferative situations and in certain conditions leading to abnormal differentiation. To localize and identify the sequences controlling this complex expression pattern, and because of their potential use in transgenic mouse models and gene therapy strategies for epidermal hyperproliferative disorders, we have thoroughly analyzed a 9 kbp region of this gene previously shown to direct proper tissue-specific and inducible expression in transgenic mice. To reproduce the K6 constitutive expression pattern, cooperation is necessary between elements located in at least two different regions, one distal between -9 and -4 kbp and one proximal between -830 and -125 bp with respect to the CAP site. The ability to induce expression under hyperproliferative conditions resides in the 2.4 kbp fragment preceding the transcription start site. When this DNA fragment was analyzed in more detail, we found that all subfragments tested contained regulatory elements necessary for inducible expression. Thus, a complex organization of K6 regulatory elements emerges, as both the constitutive and the inducible expressions of this gene are under the control of multiple elements dispersed throughout relatively large 5' flanking DNA fragments. These findings will allow the expression of cloned genes in transgenic mouse skin in response to pathological or applied hyperproliferative stimuli, avoiding the effects of their constitutive expression in other epithelia.

Animals

111In-pentetreotide scintigraphy is superior to 123I-MIBG scintigraphy in the diagnosis and location of chemodectoma.

Chemodectomas, or glomus tumours, are unusual head and neck paragangliomas. A non-invasive imaging technique, 123I-metaiodobenzylguanidine (123I-MIBG) scintigraphy, has long been used for the diagnosis of all types of paraganglioma. The aim of this study was to evaluate and compare classic 123I-MIBG scintigraphy with the more recent 111In-pentetreotide scintigraphy in the diagnosis and location of chemodectomas. We performed 123I-MIBG and 111In-pentetreotide scintigraphy in eight patients (7 females, 1 male) with histologically or radiologically confirmed chemodectomas (five carotid body and three jugulotympanic chemodectomas). 123I-MIBG uptake was visualized in four patients on planar views and SPET images (sensitivity 50%); uptake was low in three patients. Using 111In-pentetreotide scintigraphy, all chemodectomas in eight patients were visualized (sensitivity 100%) and 111In-pentetreotide uptake was high in all cases. In conclusion, our results indicate that 111In-pentetreotide scintigraphy is superior to 123I-MIBG scintigraphy in the diagnosis and location of chemodectomas. In-pentetreotide or 123I-MIBG uptake suggests a neuroendocrine origin, providing important functional information in the diagnosis of chemodectomas. Moreover, 111In-pentetreotide scintigraphy permits a good classification of patients with or without somatostatin receptors in the chemodectoma in the application of pharmacological therapy with somatostatin analogues to inoperable tumours. The main therapeutic action of cold somatostatin analogues is to inhibit hormonal hypersecretion in different neuroendocrine tumours. In chemodectomas, however, the most important effect of somatostatin analogues is to reduce tumour volume or inhibit growth progression.

3-Iodobenzylguanidine

[Clinical manifestations of infective endocarditis].

Infective endocarditis has a broad clinical picture, with systemic and multiorgan impairment. The organs most frequently involved are the heart, the central nervous system and the kidneys. Complications are caused by several mechanisms: direct effect on the heart, septic embolisms and immunological phenomena. We review some of the main clinical aspects of this disease, as well as the results of a wide series of patients with infective endocarditis from our hospital.

Aged

[Impact of secondary irradiation on operators during coronary arteriography].

BACKGROUND: The activity over cellular genetic pattern of ionizing radiation can produce stochastic and unspecific damages. Interventional cardiology operators have increasing exposure times to ionizing radiation and there is no information about the real protection conferred by simple radiological protection devices. AIM: To assess the magnitude of secondary ionizing radiation exposure of operators during conventional coronary arteriography, evaluating the radiation exposure during different beam projections and the usefulness of leaded aprons. MATERIAL AND METHODS: Ionizing radiation received by operators during coronary arteriography was measured using a Geiger-Müller Victoreen model 490 counter. The device was placed in the ventral region, covered by the leaded apron and in the unprotected dorsal region. Radiation was measured in right and left projections during fluoroscopy and shooting. RESULTS: In right projection, the intensity of ionizing radiation in ventral and dorsal regions was 1.24 +/- 1.1 and 2.9 +/- 4 mR/h respectively (p = 0.08). In left projection, the figures were 2.95 +/- 3 and 7.86 +/- 7.2 mR/h respectively (p = 0.001). During shooting in left projection the radiation exposure in ventral and dorsal regions was 9.66 +/- 6.7 and 32.8 +/- 27 mR/h respectively (p < 0.001). During shooting in right projection that figures were 10.1 +/- 16 and 20.7 +/- 39.8 mR/h respectively (p = 0.09). No correlation between radiation exposure and patients surface area was observed. CONCLUSIONS: Secondary radiation received by operators is higher during shooting and in left projections. Leaded apron confers a partial protection for ventral region, and great fluctuations in the magnitude of radiation exposure were recorded. Unprotected dorsal region receives a greater amount of radiation in left projections.

Age Distribution

[Simultaneous presentation of autoimmune thyroiditis and celiac disease in an adult].

Celiac disease may be associated with other underlying autoimmune diseases. Among these, thyroid disease has been described in around 10% of the cases with hypothyroidism being the most frequently reported. Clinical suspicion of thyroid involvement in patients with celiac disease is difficult since the symptomatology is scarce or is masked by the picture of malabsorption. Nonetheless, its detection is important since it is not solved by gluten free diet and its correction requires specific treatment. Thyroid function studies, in addition to determination of antithyroglobulin and antimicrosomal antibodies, should be considered in celiac patients refractory to conventional dietetic treatment. We herein present the case of a 65-year-old woman who consulted for a malabsorption syndrome in whom celiac disease of the adult was simultaneously presented with hyperthyroidism secondary to autoimmune thyroiditis.

Aged

[Total intravenous anesthesia with propofol in orthotopic liver transplantation in swine].

OBJECTIVE: To study the use of total intravenous anesthesia with propofol as an anesthetic model for orthotopic liver transplantation (OLT) in pigs. ANIMALS AND METHOD: Fifteen OLT were performed in pigs using portacava-jugular veno-venous shunt with an injector pump. Anesthesia was maintained by perfusion of 10 mg/kg/h propofol. Hemodynamic and biochemical measurements were recorded at the following times: AO, baseline; AI, five minutes before removal of the liver; B1, five minutes later but before starting the bypass injector pump; B2, five minutes after starting the injector pump; B3, five minutes before reperfusion; C1, five minutes after starting reperfusion, and C2, after aortic declamping. RESULTS: No cases of malignant hyperthermia appeared. When the liver was removed cardiac output decreased (p < 0.01), as did mean arterial pressure (p < 0.01), mixed venous saturation (p < 0.05), pulmonary capillary pressure and temperature (p < 0.05). Pulmonary vascular resistances increased (p < 0.05). CONCLUSIONS: The use of total intravenous anesthesia with propofol is a satisfactory experimental anesthetic model for OLT in pigs, and it prevents the possible appearance of malignant hyperthermia.

Anesthesia, General

Is the addition of ECG gating to technetium-99m sestamibi SPET of value in the assessment of myocardial viability? An evaluation based on two-dimensional echocardiography following revascularization.

The main goal of this study was to evaluate whether the addition of ECG gating to technetium-99m sestamibi single-photon emission tomographic (SPET) perfusion imaging assists the prediction of recovery of regional wall motion abnormalities after revascularization. Thirty-six patients with coronary artery disease were included in the study. All had wall motion abnormalities, and 31 (86%) had a clinical history of myocardial infarction. Coronary artery bypass surgery was performed in 18 patients and angioplasty in the remainder. All underwent ECG-gated and non-gated SPET at rest and after intravenous dipyridamole. Two-dimensional echocardiography was performed at a mean of 27 days before revascularization and at a mean of 69 days following revascularization to assess segmental wall motion changes. Perfusion prior to revascularization was analysed qualitatively and quantitatively on gated and non-gated SPET, and the results compared with those of echocardiography. Bullseye parameters were obtained from a normal database, generated from data in 40 normal volunteers, using dipyridamole ECG-gated and non-gated sestamibi SPET. There was good concordance between gated and non-gated qualitative analysis (79% with kappa=0.65) for normal, viable or necrotic segments. Gated SPET predicted functional recovery in 27 of 35 (77%) segments showing echocardiographic improvement while non-gated SPET did so in 30 of 39 (77%) such segments. Gated SPET predicted no functional recovery in 20 of 45 (44%) segments that did not show improved wall motion after revascularization, while with non-gated SPET the figure was 18 of 51 (35%). The positive predictive values of gated and non-gated SPET with regard to the recovery of wall motion following revascularization were 52% and 48%, while the negative predictive values were 71% and 67%, respectively. 99mTc-sestamibi had a low predictive value for recovery of function if visual assessment was used in the analysis of SPET data. Quantitative bullseye sestamibi parameters (defect extension and severity, reversibility and percentage change in extension), from gated or non-gated studies, appear best to distinguish which segments will display improved motility on the echocardiogram after revascularization. The addition of ECG gating does not significantly increase the predictive value of SPET imaging with regard to recovery of function.

Angioplasty, Balloon, Coronary

A pathological and immunohistochemical study of caprine pleuropneumonia induced by subspecies of Mycoplasma mycoides.

In a population of 700 goats, 150 died; of these, 29 were necropsied. Ten of the 29 goats had pleuropneumonia. Mycoplasma mycoides subsp. mycoides (Large Colony) (MmmLC), Mycoplasma mycoides subsp. capri (Mmc), and Pasteurella multocida were isolated from five of the pleuropneumonic goats. Gross and microscopical lesions were typical of caprine pleuropneumonia (CPP), with bronchopneumonia, fibrinopurulent or fibrinonecrotic pleuropneumonia and dilatation of the interlobular septa and pleura. Immunohistochemical examination with antisera against MmmLC and Mmc showed mycoplasma antigens in all 10 goats with CPP. In all cases, both MmmLC and Mmc antigens were detected together. Mycoplasma antigens were present in the lumina of the airways and alveoli, mainly inside the cytoplasm of neutrophils and macrophages, but extracellular antigen was demonstrated in areas of necrosis. Pasteurella antigens were detected in four of the 10 animals with CPP. From the histological, immunohistochemical and microbiological results it was concluded that the two mycoplasmas, acting together, caused the pleuropneumonia, with P. multocida playing a subsidiary synergistic role.

Animals

[Coexistence of chronic lymphoid leukemia and Hodgkin's disease. Immunohistochemical study].

We report a new case of coincidence of chronic lymphocytic leukemia (CLL) and mixed cellularity Hodgkin's disease (HD) in the same lymph node. These findings were corroborated by immunohistochemical study showing Reed-Sternberg (RS) cells, with typical immunophenotype in an inflammatory background, closely related to a small neoplastic lymphoid cell population. This is an uncommon feature, and, to our knowledge, this is the first case published in the Spanish literature.

Aged

A 5'-upstream region of a bovine keratin 6 gene confers tissue-specific expression and hyperproliferation-related induction in transgenic mice.

Keratins, the constituents of epithelial intermediate filaments, are precisely regulated in a tissue- and development-specific manner, although little is known about the molecular mechanisms underlying this regulation. The expression pattern of keratin 6 is particularly complex, since besides being constitutively expressed in hair follicles and in suprabasal cells of a variety of internal stratified epithelia, it is induced in epidermis in both natural and artificially caused hyperproliferative situations. Therefore, the regulatory sequences controlling keratin 6 gene activity are particularly suitable for target gene expression in a tissue-specific manner. More interestingly, they can be skin-induced in transgenic animals or in gene therapy protocols, particularly those addressing epidermal hyperproliferative disorders. To delimit the regions containing these regulatory elements, different parts of the bovine keratin 6 gene linked to a beta-galactosidase reporter gene have been assayed in transgenic mice. A 9-kbp fragment from the 5' upstream region was able to provide both suprabasal tissue-specific and inducible reporter expression.

Animals

Tissue-specific and efficient expression of the human simple epithelial keratin 8 gene in transgenic mice.

Keratin 8 is a type II intermediate filament protein found in simple epithelia. We have introduced a 12 kb DNA fragment of the human K8 locus into the germ line of mice. The transgene, containing 1.1 kb of 5' flanking sequences, 7.7 kb corresponding to the body of the gene and 3.2 kb of 3' flanking sequences, was expressed in all six lines obtained. Immunolocalization and RNA analysis of adult tissues showed that the tissue-specific expression pattern of the transgene was almost indistinguishable from that of the endogenous gene. This pattern was found in organs containing single epithelial cell types, such as trachea, lung, stomach, intestine, liver, kidney, thymus and glands. The highest expressing line, however, also produced human K8 in tissues such as stratified epithelia, where it formed part of the pre-existing keratin cytoskeleton of basal cells. Steady state levels of human K8 RNA were proportional to the copy number of the transgene, but transgene expression was less efficient, per gene copy, than that of the endogenous gene. When in the 12 kb DNA fragment the exons and introns of the gene were replaced by the Escherichia coli lacZ gene, the resulting construct showed no expression in transgenic mice. This suggests that 5' and 3' flanking sequences, in the absence of intragenic sequences, are not sufficient for K8 expression and that important control elements are located in the body of the K8 gene.

Animals

[Hereditary spherocytosis: clinical characteristics and treatment with splenectomy].

PURPOSE: To analyse the clinico-biological characteristics at diagnosis, the clinical course, and the response to splenectomy of a series of patients with hereditary spherocytosis (HS). PATIENTS AND METHODS: The clinical records of 61 patients diagnosed of HS along 30 years were reviewed. The diagnosis was based upon the existence of family history, physical findings, blood cell examination, reticulocyte count, peripheral blood spherocytes, red-cell osmotic fragility, auto-haemolysis, serum haptoglobin, LDH, non-conjugated bilirubin and direct anti-human globulin test. Data regarding the time of diagnosis and clinical course were taken into account in every case. Within the sub-group of 29 patients undergoing splenectomy, the changes in haemoglobin rates and reticulocyte and platelet counts after surgery were evaluated. RESULTS: Of the 61 patients, 35 were men and 26 women; the median age at diagnosis was 13 years (range: 0-64 years). Family history was positive in only 40% of the cases. The mean haemoglobin rate was 112 g/L (range: 46-151 g/L), over 60% of the patients having anaemia. The mean reticulocyte count was 282 x 10(9)/L (range: 31-583 x 10(9)/L), this being above 100 x 10(9)/L in 91% of the cases. Red-cell osmotic fragility with fresh blood was increased in 86% of the cases, and in 97% after blood incubation. Serum haptoglobins were decreased, whereas LDH was increased in 58% of the patients and non-conjugated bilirubin in 72%. Splenomegaly appeared in the clinical course in 87% of the patients; cholelithiasis was present in 31.5% of them. Haemoiytic crises were seen in 45% of patients, aplastic phases in 7%, and transfusion was needed by 16% of the patients to variable extents. Splenectomy was performed in 50% of the instances before 14 years of age (range: 4-64 years), and it increased haemoglobin rates in 40 g/L, anaemia being corrected in all cases; the mean reticulocyte count returned to normal, but thrombocytosis developed after surgery, it being present in 82% of the cases 2-3 months later. CONCLUSIONS: (1) Wide clinical variability is seen in HS, from severe forms requiring frequent transfusion to asymptomatic cases. (2) Highly frequent findings in HS are reticulocytosis and splenomegaly; relatively frequent were anaemia, haemolytic crisis and cholelithiasis, in this order. (3) Anaemia was always corrected after splenectomy, which also rose the haemoglobin rate even in the cases without anaemia, and returned the reticulocyte count to normal values.

Adolescent

[Primary coronary angioplasty as a choice treatment in the 1st 6 hours following acute myocardial infarction].

Primary coronary angioplasty as treatment of acute myocardial infarction preserves more myocardium and has a lower mortality than thrombolysis. Aiming to assess the feasibility of its use in Chile, we studied 64 patients aged 59 +/- 2 years old, 27 with an anterior wall and 37 with an infero-lateral wall acute myocardial infarction of 118 +/- 62 min of evolution. Coronary angiography, performed 98 +/- 47 min after diagnosis, showed non significant disease in one, one vessel disease in 26 (40%), two vessel disease in 17 (27%) and three vessel disease in 20 (31%) patients. Responsible arteries for infarction were the anterior descending in 26 (40%), circumflex in 9 (14%), right in 27 (42%), a saphenous bridge in one and left main disease in one patient. In one patient with an obstruction over 50% and in two patients with left main disease, angioplasty was not attempted. The procedure was successful (defined as a residual lesion of less than 50%) in 56 of 61 patients (92%) and failed in four. One patient was re-perfused with intracoronary streptokinase. The delay in reperfusion was lower during working than non-working hours (89 +/- 48 vs 113 +/- 39 min). Four patients (6%) died during hospitalization, two had a reinfarction, two had a new vessel occlusion and three had a spontaneous ischemia. Eleven patients were operated during hospitalization and in two this was an emergency procedure. After 1993, mortality was lower (one of 55 patients) than before (three of nine). It is concluded that early coronary angioplasty in acute myocardial infarction is feasible in Chile, with a high degree of success.

Adult

Opposite effects of breakfast vs. oral glucose on circulating androgen levels in healthy women.

Since certain hormone abnormalities can be food-dependent as in some cases of nodular adrenal hyperplasia, as a first step to study other more frequent endocrine disorders, using a standard meal as means of a more physiologic stimulus, we investigated in healthy women whether or not the changes in serum glucose, insulin, cortisol, and androgens are different following a breakfast than after oral glucose alone. Ten women (group 1) ingested a 725 kilocalories (173 kiloJoules) breakfast and ten women (group 2) ingested a 100-g glucose load at 8:00 A.M. Serum glucose, insulin, cortisol, dehydroepiandrosterone sulfate (DHEAS), free testosterone (free-T), and androstenedione (A) were determined every 30 min for the next 2 h. Serum glucose rose higher in group 2 than in group 1 (p < or = 0.05), yet insulin increased similarly in both groups. In group 1 free-T and DHEAS increased at 30 min (p < or = 0.05) while cortisol decreased (p < or = 0.04); A did not change. On the contrary, in group 2 only a decrease in free-T (p < or = 0.01) was detected. In these healthy women, serum androgen changed inversely depending on the type and composition of the oral stimulus used. The simultaneous increase of serum insulin, free-T and DHEAS coinciding with a cortisol decrease may enhance insulin anabolic effects following breakfast, but not after oral glucose alone.

Administration, Oral