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A Ramírez

Publications and source records attributed to A Ramírez.

At least 55 records · Page 3Linked to original sources
PubMed1999

Calculation of airborne radioactivity in a Technegas lung ventilation unit.

Airborne contamination by 99Tcm has been monitored in the Nuclear Medicine Department in our hospital to assess the risk of internal contamination to occupational workers exposed to Technegas studies. An air sampler fitted with a membrane filter was used. The optimum time for air absorption for obtaining the maximum activity in the filter was calculated. Maximum activity in the membrane filter ensures minimum uncertainty, which is especially important when low-level activities are being measured. The optimum time depends on air absorption velocity, room volume and filter efficiency for isotope collection. It tends to 1/lambda (lambda = disintegration constant for 99Tcm) for large volume and low velocity. Room activity with the air pump switched on was related to filter activity, and its variation with time was studied. Free activity in air for each study was approximately 7 x 10(-4) the activity used, and the effective half-life of the isotope in the room was 13.9 min (decay and diffusion). For a typical study (630 MBq), the effective dose to staff was 0.01 microSv when in the room for 10 min.

Air Pollutants, Radioactive↗
PubMed1999

Exocrine pancreatic disorders in transsgenic mice expressing human keratin 8.

Keratins K8 and K18 are the major components of the intermediate-filament cytoskeleton of simple epithelia. Increased levels of these keratins have been correlated with various tumor cell characteristics, including progression to malignancy, invasive behavior, and drug sensitivity, although a role for K8/K18 in tumorigenesis has not yet been demonstrated. To examine the function of these keratins, we generated mice expressing the human K8 (hk8) gene, which leads to a moderate keratin-content increase in their simple epithelia. These mice displayed progressive exocrine pancreas alterations, including dysplasia and loss of acinar architecture, redifferentiation of acinar to ductal cells, inflammation, fibrosis, and substitution of exocrine by adipose tissue, as well as increased cell proliferation and apoptosis. Histological changes were not observed in other simple epithelia, such as the liver. Electron microscopy showed that transgenic acinar cells have keratins organized in abundant filament bundles dispersed throughout the cytoplasm, in contrast to control acinar cells, which have scarce and apically concentrated filaments. The phenotype found was very similar to that reported for transgenic mice expressing a dominant-negative mutant TGF-beta type II receptor (TGFbetaRII mice). We show that these TGFbetaRII mutant mice also have elevated K8/K18 levels. These results indicate that simple epithelial keratins play a relevant role in the regulation of exocrine pancreas homeostasis and support the idea that disruption of mechanisms that normally regulate keratin expression in vivo could be related to inflammatory and neoplastic pancreatic disorders.

Animals↗
PubMed1999

[Infection by Staphylococcus lugdunensis: clinico-microbiologic characterization of 25 cases].

INTRODUCTION: S. lugdunensis is a recently described staphylococcal species with morphologic characteristic similar to those of S. aureus. It has been associated to a variety of clinical infections. In this paper we present the clinical and microbiological features of S. lugdunensis isolates from 25 patients. MATERIALS AND METHODS: We have studied the S. lugdunensis isolates obtained from clinical specimens in our laboratory over a three-year period, 1994-96. For all isolates we determined the presence of clumping factor, Dnase, free coagulase in tube and ornithine decarboxylase (ODC). Full identification was performed with API ID32-Staph strips (bioMérieux) and antimicrobial susceptibility with commercial broth microdilution MIC panels (PASCO System, Difco). RESULTS: We obtained 38 S. lugdunensis isolates from 25 patients. The clinical specimens were: breast exudate/pus (8), blood (5), surgical wound (2), urine (2), nasal exudate (2), peritoneal fluid (1), pleural fluid (1), venous catheter (1), Tenckoff catheter (1), bartholin pus (1), ulcer (1). The isolates were considered clinically significant in 20 patients, whereas those of the remaining 5 patients were considered mere colonizers. All isolates were clumping factor (+), ODC (+), Dnase (-) and free coagulase (-). 16/23 (69.5%) were susceptible to penicillin and only one isolate was methicillin-resistant. CONCLUSIONS: We have isolated S. lugdunensis from a great variety of clinical specimens (blood, sterile body fluids, urine, skin, abscesses and nasal mucosa). It is specially remarkable the association with non-puerperal mastitis. The presence of clumping factor in all isolates can easily lead to misidentification as S. aureus. The ODC test appears as a good screening method for detecting S. lugdunensis. S. lugdunensis shows a good susceptibility to betalactamic an other antimicrobial agents.

Adult↗
PubMed1999

[Angioplasty in acute myocardial infarction. Early and late results].

BACKGROUND: The usefulness of angioplasty in the first hours of an acute myocardial infarction is widely demonstrated. However, its long term effects are less well known. AIM: To report the effects of coronary angioplasty on early and late outcome of patients with acute myocardial infarction. PATIENTS AND METHODS: A non-randomized, consecutive and retrospective analysis of the hospital and late outcome of 70 patients, aged 35 to 85 years, subjected to coronary angioplasty during an acute myocardial infarction. Patients were followed during 12 to 60 months. RESULTS: Angioplasty was performed 5.3 +/- 5 hours after the initial symptoms. Anterior descendent artery was occluded in 63% of patients with a 99.5% luminal occlusion and TIMI 0-1 anterograde flow. An angiographic success was achieved in 83% of procedures with a residual stenosis of 32.3%. Recurrent ischemia was observed in 6% of patients, that were treated with a new revascularization procedure. Thirteen percent of patients died, all due to cardiogenic shock. Severe ventricular failure and failure of revascularization influenced mortality. During the first year of follow up there was a 3.3% mortality and 3.3% of patients required a new revascularization procedure. Eighty percent of patients were asymptomatic and event-free. CONCLUSION: Angioplasty was a useful therapeutic procedure in this group of patients.

Adult↗
PubMed1999

Ureteral complications after gasless laparoscopic hysterectomy.

Laparoscopic hysterectomy is becoming a more common operation. Gasless laparoscopy initially seems to be a better technique, reducing CO2 complications and allowing the use of conventional instruments rather than more expensive laparoscopic tools. We report our experience with 50 cases of laparoscopic hysterectomies, 5 of which were performed using a gasless technique. Of these five cases, there were two cases of ureteral stenosis. Ureteral injuries are common with hysterectomy, even in nonlaparoscopic procedures, and the literature is replete with recommendations to avoid this damage. In the gasless procedure, the ureters cannot be repositioned completely from the cervix after the hydrodissection. Extreme caution must be taken when applying bipolar or monopolar energy. The abdominal cavity shape does not allow complete avoidance of the ureters using the gasless technique. We have decided not to use a gasless technique with hysterectomy. We believe that the actual complication rate may be higher than reported, due to investigators' reluctance to report such complications. Our hope is that this report will encourage other investigators to help establish a more accurate rate of possible complications associated with this procedure.

Adult↗
PubMed1998

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↗
PubMed1998

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↗
PubMed1998

[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↗
PubMed1998

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↗
PubMed1998

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↗
PubMed1998

[Endovascular stent implantation in the treatment of coronary artery disease: angiographic, and immediate and late clinical results].

BACKGROUND: Coronary revascularization allows a better survival and quality of life in high risk patients with coronary artery disease. AIM: To report the experience in stent placement as treatment for obstructive atherosclerotic coronary artery disease. PATIENTS AND METHODS: A prospective analysis of 105 stent placements. A morphological and quantitative analysis of coronary angiograms, using an electronic caliper, was performed. Patients were followed during their hospital stay and after discharge. RESULTS: In four of 112 coronary lesions, it was not possible to liberate the stent and in 108, it was successfully placed (48 in anterior descending, 19 in circumflex, 36 in right coronary arteries and 5 in saphenous aortocoronary by-pass. Lesions with stent implantation were type A in 11%, B1 in 30%, B2 in 44% and C in 15%. Reference diameter was 3.13 +/- 0.58 mm. After placement, luminal diameter increased from 0.95 +/- 0.43 to 2.99 +/- 0.46 mm, with a final stenosis of 7.2 +/- 10.1%. Angiographic success was obtained in 99% and procedure success in 98%. Hospital mortality was 0.98%. After a mean of eight months follow up, 91% of patients is free of major cardiac events. In 17% angina recurred and 5% required a new revascularization. There were no late cardiac deaths, acute stent thrombosis or infarction in relation to the treated lesion. CONCLUSIONS: In these patients, stent placement has had excellent immediate and late results.

Adult↗
PubMed1998

[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↗
PubMed1998

[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↗
PubMed1998

[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↗
PubMed1997

[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↗