Biomedical subjects

A Ramírez

Publications and source records attributed to A Ramírez.

At least 73 records · Page 4Linked to original sources

PubMed1996

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↗

PubMed1996

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↗

PubMed1996

[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↗

PubMed1995

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↗

PubMed1995

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↗

PubMed1995

[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↗

PubMed1995

[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↗

PubMed1995

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↗

PubMed1995

[Delusional disorders with delirium of somatic type].

The delusional disturbance is characterized by the presence of persistent delusions that are not bizarre, which cannot be attributed to schizophrenia, mood state disorders, substance abuse or organic brain disease. We report a 37 years old male that presented the disease during the last seven years and had very little response to a two months course of pimozide, a neuroleptic whose effectiveness in this disease has been suggested.

Adult↗

PubMed1994

Transcriptional activation of histone H1 zero during neuronal terminal differentiation.

We have examined the central nervous system (CNS) of developing and adult transgenic mice carrying sequences upstream of the histone H1 zero gene fused to the E. coli beta-galactosidase gene (lac Z). The transgene is induced in a subset of the neuronal population during postnatal development, coinciding with neuronal terminal differentiation. At postnatal day 9, the earliest time at which the transgene product can be detected, positive neurons are observed in the granular layer of the cerebellar cortex and in the pyramidal fields of the hippocampus. The transgene is then induced in other areas of the CNS, such as the neocortex, thalamus, hypothalamus, olfactory bulb, globus pallidus superior and inferior colliculus, substantia nigra, pontine nuclei and brain stem. Induction is unrelated with determination and quiescence, which are essentially prenatal. The overlapping of the temporal and regional patterns of transgene activity with those of the endogenous protein shows that the accumulation of H1 zero in differentiating neurons is at least in part under transcriptional control. In the light of these results, the H1 zero gene appears as the only mammalian histone gene that specifically responds to terminal differentiation. However, not all terminally differentiated neurons express H1 zero at detectable levels. For instance, Purkinje cells are negative. In neurons, terminal differentiation appears thus as a necessary, but not a sufficient condition for increased H1 zero expression.

Animals↗

PubMed1994

Effects of nitric oxide inhibition on the renal papillary blood flow response to saline-induced volume expansion in the rat.

1. Evidence indicates that nitric oxide (NO) exerts a paracrine influence in the renal medulla. Increases in papillary blood flow are thought to be an important determinant of the renal response to extracellular volume expansion. Therefore, in the present study, we have evaluated the role of NO in mediating papillary blood flow (laser-Doppler flowmetry) and excretory responses to volume expansion with isotonic saline (3% body weight, 15 min). 2. Infusion of the NO synthesis inhibitor N omega-nitro-L-arginine methyl ester (10 micrograms min-1 kg-1), significantly attenuated the renal diuretic and natriuretic responses to volume expansion as well as the renal hydrostatic interstitial pressure increase induced by this manoeuvre. The percentages of the water and sodium excreted in 1 h by the N omega-nitro-L-arginine methyl ester-pretreated animals were 36% and 40% of the load, whereas those of the control animals were 44% and 65%, respectively. 3. In similar experiments performed in the exposed papilla of Munich Wistar rats, the same dose of N omega-nitro-L-arginine methyl ester reduced basal papillary blood flow and blunted the elevation in papillary blood flow induced by volume expansion (6% versus 16% in the control animals). 4. These results indicate that the inhibition of NO synthesis blunts the renal excretory and papillary responses to volume expansion, suggesting that NO modulates these responses through changes in papillary blood flow and renal interstitial hydrostatic pressure.

Animals↗

PubMed1994

Sequences 5' of the bovine keratin 5 gene direct tissue- and cell-type-specific expression of a lacZ gene in the adult and during development.

Expression of keratin K5 (and K14) in multilayered epithelia occurs predominantly in the basal layer of proliferating keratinocytes. When a keratinocyte becomes committed to terminal differentiation, it moves out of the basal layer towards the epithelial surface. As part of this program of terminal differentiation, the expression of K5 (and K14) is downregulated in suprabasal cells, and new pairs of differentiation-specific keratins are expressed. To define the cis-acting DNA sequences required for K5 cell-type- and differentiation-specific expression, chimeric gene fusions between portions of the bovine keratin K5 locus and the Escherichia coli lacZ gene were used to generate transgenic mice. In the genomic fragment consisting of 5.3 kb of 5' flanking sequences, 6.1 kb corresponding to the body of the gene and 4.5 kb of 3' flanking sequences, the subfragment extending from -5300 bp to +138 bp was the smaller region that directed lacZ expression to stratified epithelia in a manner analogous to the endogenous keratin K5. Proximal sequences from -1300 bp to +138 bp were inactive. We also determined the expression pattern of keratin K5 during mouse development using an antiserum specific for mouse keratin K5. Expression was first detected in ectodermal cells of 11.5 days postcoitum embryos, and from day 13.5 postcoitum onwards K5 was detected in the precursors of most epithelia and organs which express K5 at adult stages. This pattern was reproduced, with few differences, by the construct with sequences from -5300 bp to +138 bp fused to the lacZ gene. These findings identify sequences between -5.3 kb and -1.3 kb of the bovine K5 gene as being important for cell-type- and differentiation-specific gene expression both during mouse development and in the adult.

Aging↗

PubMed1994

Renal effects of nitric oxide synthesis inhibition in cirrhotic rats.

In the present study, we have characterized the renal response to inhibition of endogenous nitric oxide (NO) synthesis [intravenous NG-nitro-L-arginine methyl ester (L-NAME) for 3 h] in anesthetized cirrhotic rats, with (ASC) and without (CIR) ascites, at doses that do not change blood pressure (BP). Administration of L-NAME induced opposite effects on water (UV) and sodium (UNaV) excretion in cirrhotic and control animals. Infusion of 1 microgram.kg-1.min-1 of L-NAME in CIR (n = 5) decreased renal plasma flow (RPF) at the end of the 3-h period, whereas UV, UNaV, and glomerular filtration rate (GFR) were unaltered. In contrast, infusion of L-NAME at 10 micrograms.kg-1.min-1 in six more CIR increased UV and UNaV significantly by the 1st h, without changes in BP or GFR, and these parameters remained elevated throughout the experiment. Infusion of 1 microgram.kg-1.min-1 in ASC (n = 6) did not change BP or GFR but significantly enhanced UV and UNaV after the 1st h. These effects were prevented by pretreatment with L-arginine (0.1 mg.kg-1.min-1) in another group of ASC infused with 1 microgram.kg-1.min-1 of L-NAME. These results indicate that, in ASC and CIR cirrhotic rats, inhibition of NO synthesis at nonpressor does improves renal excretion of sodium and water via a decrease in tubular reabsorption. NO is an important mediator of the renal excretory and hemodynamic alterations of experimental liver cirrhosis.

Amino Acid Oxidoreductases↗

PubMed1994

[Evaluation of coronary revascularization: comparison between perfusion with dipyridamole Tc99m sestaMIBI and amrinone-echocardiography as predictors of viability].

We studied left ventricular perfusion and motility in 37 patients with coronary artery disease and disturbances of parietal motility, aged 57 +/- 9 years old, before and after revascularization. Perfusion was assessed with dipyridamole-tc99m MIBI SPECT and motility was assessed with two dimensional echocardiography with amrinone. Myocardial segments were defined as normal, viable or necrotic in both studies. Eighteen subjects were subjected to angioplasty and 19 to coronary bypass surgery. Submitted SPECT and echocardiography were repeated 64 +/- 15 and 69 +/- 23 days after revascularization respectively. The concordance between SPECT and echocardiographic pre-revascularization diagnosis was 60.1% Eighty one percent of segments considered viable with SPECT and 71% thus considered with echocardiography improved after revascularization. Likewise, 50% of segments considered necrotic with SPECT and 68% of segment thus considered with echocardiography did not improve. It is concluded that although there is a good concordance between both methods, they have limitations on the study of myocardial viability and should be considered as second choice.

Adult↗

PubMed1994

[Tomographic myocardial perfusion (SPECT) using 99mTc sestamibi-dipyridamole and 2-d-echocardiography with amrinone pre and post myocardial revascularization in 2 cases].

We report two male patients aged 50 and 55 years old with coronary artery disease who were treated with surgical revascularization and angioplasty respectively. To assess viable and ischemic myocardial territories, they were studied before and after revascularization with radionuclide perfusion SPECT with Tc99m-Sestamibi under Dipyridamole and with 2-D echocardiography at baseline and after the use of amrinone. Improvement in relative perfusion on SPECT and wall motion on 2-D echocardiography indicated tissue recovery.

Amrinone↗

PubMed1993

Age-related changes in the metoclopramide-induced prolactin release in nulliparous women.

OBJECTIVE: To assess the metoclopramide-stimulated PRL response in nulliparous women as a function of chronological age (CA). DESIGN: Open and prospective study. SETTING: Outpatient endocrine clinic of a third level medical institution. PATIENTS: Fifty-one clinically healthy volunteer nulliparous women 15.8 to 48.2 years of age, with regular menses at least 1 year before the study (except 3 postmenopausal women) and no regular drug ingestion during the last 6 months, studied on days 18 to 22 of their menstrual cycle. INTERVENTIONS: After a 30-minute rest, three basal blood samples were obtained; oral metoclopramide (10 mg) was administered followed by subsequent blood samples at 60, 90, and 120 minutes. MAIN OUTCOME MEASURES: Duplicate serum PRL determinations were performed by RIA in all samples with P and E2 only in the pool of the basal samples. Hypothesis was formulated before data collection. RESULTS: All menstruating women had serum P levels > or = 4.0 ng/mL (> or = 12.72 nmol/L). A linear correlation was observed between CA and the serum PRL response, and also between CA and serum E2. Multiple regression analysis showed that CA and body mass index had the most marked effect on PRL response. Women < or = 25.0 years old had a serum PRL response and mean basal serum E2 levels lower than women > 25.1 years old. CONCLUSIONS: The metoclopramide-induced PRL response in nulliparous women augmented linearly as CA increased, suggesting a gradual decrease in the dopaminergic tone in older women, perhaps partially compensated by a high estrogen level to prevent an unrestrained rise in serum PRL levels.

Administration, Oral↗

PubMed1993

Ambulatory blood pressure monitoring and diastolic left ventricular abnormalities in established and borderline hypertension.

In order to evaluate left ventricular diastolic function by means of Doppler echocardiography in borderline and established hypertension, identified by office and ABPM, compared with normotensives, 54 subjects: 15 normotensives, 11 borderlines and 28 nontreated mild to moderate essential hypertensives were studied. Age and weight were similar among groups. Established hypertensives showed higher left ventricular mass index (p < 0.05), peak velocity of late left ventricular filling (peak A; p < 0.01), ratio peak A/peak velocity of early ventricular filling, peak E (p < 0.01), velocity time integral of systolic atrial volume (p < 0.001), deceleration half time of peak early diastolic inflow velocity (p < 0.05), left ventricular isovolumic relaxation period (IRP; p < 0.01) than normotensives and lower Doppler indexes of early diastolic left ventricular filling (p < 0.01), peak filling rat normalized to mitral stroke volume (PFRn; p < 0.01) than normotensives. Although borderline hypertensives showed intermediate LVM and Doppler indexes between hypertensives and normotensives only IRP (p < 0.05) and PFRn (p < 0.05) were significant different to normotensives. In conclusion, established hypertension leads to abnormalities in left ventricular diastolic function which can be detected by Doppler echocardiography. In borderline hypertension, the left ventricular diastolic abnormalities are predominantly related to the active process of early diastole. Therefore, these indexes may be early markers of left ventricular dysfunction in hypertension.

Adult↗

PubMed1993

[Percutaneous transluminal angioplasty in stenosis of Blalock-Taussig pulmonary systemic shunt in an adult patient].

AIM: The report of a female patient with tricuspid atresia and severe stenosis of the pulmonary artery, stenosis of the left pulmonary-systemic shunt and occlusion of the right systemic-pulmonary shunt. BACKGROUND: The use of transluminal angioplasty has been extended to the treatment of several congenital cardiopathies and, in some of them, it is the therapeutic procedure of choice. METHODS: Dilatation of the distal stenosis of the pulmonary-systemic shunt with a coaxial system composed initially by an 8 French right Judkins carrier catheter with a soft tip through which a 0.014" (0.036 cm) coronary angioplasty guidewire and 3 and 4 mm balloon catheters were advanced successively. Subsequently a 0.028" interchange Rosen guide was advanced, gradually introducing balloon catheters up to 8 mm of diameter. RESULTS: The dilatation with balloon catheter systems of increasing diameter allowed to amplify the stenosis zone, improving arterial oxygen partial pressure and saturation without evidences of left lung hyperflux. Considering the anatomic characteristics of the pulmonary systemic shunt, the use of carrier catheters facilitates the penetration of balloon catheters to the stenosis zone. CONCLUSION: Percutaneous transluminal angioplasty may be used with success in patients with stenosis of Blalock-Taussig shunts, independent of the anastomosis curvature and even if the magnitude of the stenosis is significant.

Adult↗