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Biomedical subjects

E Medina

Publications and source records attributed to E Medina.

At least 73 records · Page 4Linked to original sources
PubMed1996

[Cerebral toxoplasmosis in AIDS patients, CT and MRI images and differential diagnostic problems].

Cranial computed-tomographies (CT) and magnetic resonance imaging (MRI) of 14 patients with AIDS and central nervous system toxoplasmosis (CNST) were reviewed. In spite of the low specificity of CT and MRI findings in CNS mass lesions of AIDS patients, there are some features which have been observed as more typical of CNST, namely: 94.9% of the lesions were round shaped and 94.5% had ring or nodular enhancement; 81.3% of the cases presented multiple lesions; 60.2% of the lesions were localized at the cerebral cortical or corticomedullary junction (100% of the cases showed at least 1 lesion in this localization); 34.6% of the lesions had less than 1cm in diameter.; on nonenhanced CT, 91.3% of the lesions were hypodense.; On T2-weighted MR images, 53.4% of the lesions had at least one hypointense zone on T2-weighted images. The existence of target-shaped lesions with hypointense centre on T2-weighted MR images (29.3% the observed lesions) is also suggestive of CNST, which, to our belief, had not been previously reported and will need confirmation with larger series. The visualization of iso/hyperdense lesions on nonenhanced CT or irregular shape lesions is uncommon in CNST. The finding of a solitary lesion, on CT or MR, it is not, by itself, a good criterion of differential diagnosis.

AIDS-Related Opportunistic Infections↗
PubMed1996

[Splenic infarction].

A 53-year-old male suffered splenic infarction etiologically related to atrial fibrillation and non-obstructive hypertrophic cardiomyopathy. The main clinical manifestations were a one-month history of epigastric and left upper quadrant pain, with tenderness to palpation in the later zone. Laboratory tests revealed a slight leucocytosis (14.700) with left shift and a marked increase in LDH concentration (945 IU). Abdominal CAT and arteriography established the diagnosis, Echography proved normal. Patient evolution was satisfactory with conservative medical treatment. We conclude that splenic infarction should be considered in all cases of acute or chronic pain in the left hypochondrium. The diagnosis is established by CAT, arteriography and hepatosplenic gammagraphy. Medical management is initially advocated, surgery being reserved for those cases involving complications or in which diagnosis is not clear. Emphasis is placed on the main etiological, clinical, diagnostic and management characteristics of splenic infarction.

Angiography↗
PubMed1995

[Importance of HDL cholesterol determination in the evaluation of coronary risk in clinical practice].

OBJECTIVE: To validate to what extent the isolated determination of total Cholesterol (TC) is effective when seeking to predict coronary risk. DESIGN: An observational crossover study of the analytic determinations of the clinics which systematically request TC and HDL-Cholesterol (HDL)--case-finding method. SETTING: Health Centre. PARTICIPANTS: 631 analytic determinations, with samples from people who attended a Health Centre between May and November 1992, were studied. MEASUREMENTS AND MAIN RESULTS: As proof of certainty the Atherogenic Index (AI) was used for the relative risks (RR) of suffering a coronary event in line with the Framingham study. The confidence limits (CL) were calculated to 95% in order to quantify random error and permit comparison. On varying the cut-off points of TC the indicators changed, being more sensitive (S) and less specific (E) with the lower figures: 180 mg/dl, RR > 1, S = 97.5% (CL: 100-94.7) and E = 30.5% (36.8-24.2); RR > 2, S = 100%, E = 22.1% (26.9-17.3) and RR > 3, S = 100%, E = 20.8% (25.3-16.3). As values of TC increase, S diminishes and E increases: 250 mg/dl, RR > 1, S = 48.3% (57.2-39.4), E = 87.2% (91.8-82.6); RR > 2, S = 58.6% (76.5-40.7), E = 77.2% (82-72.4) and RR > 3, S = 63.6% (92-35.2), E = 75.3% (80.1-70.5). CONCLUSIONS: HDL must be determined if TC is -200 mg/dl. If everyone with RR > 2 is to be detected, HDL-cholesterol from TC > or = 180 mg/dl must be measured.

Adult↗
PubMed1995

Liver transplantation in patients with Budd-Chiari syndrome.

Patients with Budd-Chiari syndrome (obstruction of the hepatic veins) and associated hepatic insufficiency may be candidates for orthotopic liver transplantation (OLT). In our series of 405 OLT patients, 3 were transplanted due to Budd-Chiari syndrome (0.7%). The indication for liver transplantation in these patients was severe hepatic insufficiency (chronic in two and acute in the third one). Morphologic study of the obstructions revealed apparently different causes, including thrombi, membranous webs in hepatic veins, and hydatid cyst compression. The surgical technique employed in these transplantations was similar to that for other etiologies. Due to its implications for the future course of OLT, it is important to determine the exact etiology of Budd-Chiari syndrome in the pretransplant period and to treat the patients with early and long-term anticoagulant therapy to avoid syndrome recurrence.

Adolescent↗
PubMed1995

Treatment of esophageal varices by endoscopic ligation in children.

Endoscopic variceal ligation (EVL) is an alternative technique to endoscopic variceal sclerotherapy (EVS) to treat esophageal varices. This method consists of mechanical ligature and thrombosis of varices using elastic rubber rings. During an 11-month period, nine pediatric patients with esophageal varices secondary to portal hypertension were treated by EVL. Extrahepatic portal vein obstruction was the cause of portal hypertension in 5 patients and in 4 cases the cause was intrahepatic disease. The average age of the patients was 8 years (range: 2-15). Five patients had bled from esophageal varices previously. Two were actively bleeding at the time of the procedure. Endoligature was performed prophylactically in four patients. Fifty varix ligations were performed in 26 separate sessions. In children older than ten years, EVL was performed under intravenous sedation. Two mild rebleeds have occurred in this group and responded to repeated ligature. Varices were reduced in grade in all patients. Six patients achieved variceal eradication. Recurrence of varices was not encountered. No major complications occurred and there were no treatment failures. These early results suggest that endoscopic ligation is a safe and effective method for the control of esophageal varices in children.

Adolescent↗
PubMed1995

[Medical care in Santiago, 1993].

Results of morbidity and medical care surveys performed in Santiago in 1993-94 are presented in this paper. The study has been done in an aleatory population sample of 4,700 people coming from 1,000 dwellings. Main results are as following: The Health National Fund (FONASA) is the most important financing medical care's agency in Santiago (49% out of total population). A majority of medical services are given in private offices or clinics. Medical care systems show significant differences among the studied city districts. A significant direct correlation between people's income and private practice is noticed. One half of acute diseases had medical care and the other half used self care practices; the proportion of medical care is 29% in the case of chronic disease patients. National Health Service eligible people show a significant higher morbidity rate and medical consultation rate than other groups. Lack of medical care mainly depends on low severity of illness episodes or lack of symptoms in chronic disease conditions. In 12% out of total cases, lack of medical care was due to problems in the medical care systems. The quality of care was judged "good or excellent" by 82% of the people, "fair" by 9%, and "bad or deficient" by the remaining 8%. Personal expenditures due to health care are high, one third depending on medical care and two thirds on dental care. In the case of medical care the reasons for expenditures are linked to chronic diseases (60%), acute diseases (28%), injuries and health examinations (15%). Main activities causing personal disbursements are the purchase of drugs (44%), medical visits (30%), laboratory tests (13%) and hospital charges (7%).(ABSTRACT TRUNCATED AT 250 WORDS)

Chile↗
PubMed1995

[Does the antisecretory agent used affect the evolution of upper digestive hemorrhage?].

OBJECTIVE: To investigate whether omeprazole has improved morbidity-mortality among patients with upper gastrointestinal bleeding of non-variceal origin in comparison with ranitidine. MATERIAL AND METHODS: Prospective, randomized and open study. We study 519 consecutive patients admitted to our Service between June 1991 and January 1993 for upper gastrointestinal bleeding of peptic origin, dividing the patients into two randomized groups that were homogeneous in terms of age, sex, previous history of gastric disease and upper gastrointestinal bleeding, intake of non-steroidal antiinflammatory drugs, and the severity of bleeding on admittance. Thus, Group A consisted of 252 patients treated immediately upon arrival at the emergency ward with 50 mg intravenous ranitidine, followed by a further 50 mg every 6 hours. Group B in turn consisted of 267 patients initially given a bolus dose of 80 mg omeprazole intravenously, followed by an additional 40 mg every 8 hours for 48 hours. Forty mg were subsequently administered every 12 hours until hospital discharge. Endoscopy was performed in all cases within the first 24 hours following admittance, those patients with active upper gastrointestinal bleeding resulted from Forrest-type ulcer of subjected to endoscopic sclerotherapy were excluded. RESULTS: Duodenal ulcer was the most common cause of bleeding, followed by gastric ulcer and acute lesions of the mucosa. Emphasis should be placed on the high incidence of previous non-steroidal antiinflammatory drug intake in our series (54.5%). We encountered no statistically significant differences between the two groups on comparing bleeding stigmata, transfusion requirements, recurrences, emergency surgery, the duration of hospital stay, and mortality. CONCLUSIONS: Both drugs were found to possess a similar efficacy in treating upper gastrointestinal bleeding of peptic origin.

Adolescent↗
PubMed1995

[Prevalence of digestive symptoms in normal adult women and its association with cholelithiasis].

The aim of this work was to study the prevalence of biliary diseases and digestive symptoms in normal adult women. Four hundred nineteen women were chosen; of these 145 were discarded due to previous gastrointestinal diseases (20), previous gastrointestinal complaints (38) and previous cholecystectomy (85). Two hundred seventy six women were subjected to abdominal ultrasound examination; of these 53 had cholelithiasis and in three a gallbladder cancer was suspected (and confirmed by surgery). Considering women with previous cholecystectomy, cholelithiasis and gallbladder cancer, a 33.6% prevalence of biliary diseases can be inferred. An interrogation about gastrointestinal symptoms was performed to women subjected to ultrasound examinations, by 2 professionals unaware of ultrasound results. A high frequency of pyrosis, food intolerance and constipation was found, not observing differences between women with or without cholelithiasis. However, these last women had a higher frequency of upper abdominal pain. Both groups had also a high rate of previous surgical procedures.

Adult↗
PubMed1995

[Epidemiological and etiological aspects of upper digestive hemorrhage. Multicenter study in nine Chilean hospitals (1980-1990)].

An epidemiological survey about the incidence of upper gastrointestinal bleeding during three periods (1980, 1985 and 1990), was performed in 9 Chilean hospitals. Its annual incidence decreased in 1990, when compared to 1980. Likewise the etiologies changed, with an increase in the incidence of duodenal ulcers and a decrease in the incidence of erosive gastritis and bleeding of unknown origin in 1990. A seasonal variation with higher bleeding rates in autumn was also recorded.

Chile↗
PubMed1995

[Smoking in Santiago, 1993-94].

The aim of this work was to study smoking habits, alcohol and drug use and living standards in a random sample of 1000 dwellings and 4700 people of Santiago through periodic surveys during 1993 and 1994. Forty nine percent of dwellings had at least one inhabitant that was a daily smoker and 73% had at least one occasional smoker. Thirty seven percent of subjects older than 15 years were smokers (40% of men and 35% of women), 27% were presumably addicted to tobacco and 16% former smokers. Alcohol abuse had a prevalence of 2.3%. The highest prevalence of smoking was noticed in low socioeconomical strata. Smoking was not related to educational level or emotional disturbances. Frequency of alcohol abuse or marihuana use was 8.8 times higher in former smokers and 25 times higher in actual smokers, compared to people that never smoked. Comparing these results with previous population surveys, the prevalence of smoking increased in the period 1971-1986 from 47 to 51% in men and from 26 to 43% in women. On the other hand, during the period 1986-1994 the prevalence decreased from 51 to 40% in men and from 43 to 35% in women.

Adolescent↗
PubMed1994

Photosynthesis and water relations of savanna tree species differing in leaf phenology.

Godmania macrocarpa Hemsley, a deciduous tree characteristic of fire protected areas of the savanna region of central Venezuela, was more drought tolerant, allocated more N to leaves and had consistently higher photosynthetic rates than Curatella americana L., a ubiquitous species growing successfully within the grasslands of tropical American savannas. Godmania macrocarpa maintained higher leaf conductance and photosynthesized at higher xylem water tensions than C. americana. As the dry season progressed, G. macrocarpa was more affected by water stress than C. americana, which may explain why G. macrocarpa shed its leaves before forming new leaves. For both species, leaf sap osmolality was strongly correlated with, but not completely accounted for by, soluble sugars. Integrated water-use efficiency, as measured by delta(13)C, was similar for both species, but young leaves were more efficient than old leaves. Water-use efficiency of adult leaves was similar in both species as a result of higher photosynthetic rates in G. macrocarpa and lower leaf conductances in C. americana. Compared to G. macrocarpa, instantaneous photosynthetic N-use efficiency was higher in C. americana despite its lower maximum photosynthetic rates. The absence of G. macrocarpa trees from open grasslands, despite their high productive capacity, is possibly the result of unfavorable conditions for germination, poor survival of seedlings, and lack of resistance against fire.

Journal Article↗
PubMed1994

Lymphocyte activation in HIV-1 infection. II. Functional defects of CD28- T cells.

OBJECTIVES AND DESIGN: The expression of the accessory molecule CD28 was compared in various populations of T and natural killer (NK) cells from HIV-1-negative and HIV-1-positive individuals and correlated with activation using mitogens in vitro. METHODS: Multiparameter flow cytometric analysis using combinations of CD3 CD28 and other markers was performed together with absolute cell counting in peripheral blood. Blast transformation and proliferative responses were also quantitated using the Cytoronabsolute after stimulation with phytohaemagglutinin (PHA) and anti-CD3. CD28- cells were also purified to confirm the observations. RESULTS: In HIV-1-negative individuals > 90% of CD3+ T cells were CD28+ and responded to stimulation, while CD3- CD16+ CD57+ NK-like cells were CD28- and failed to respond. In HIV-1-positive individuals the expression of CD28 was greatly reduced and the proportion of CD3+CD28- T cells expanded. CD8 lymphocytosis was caused entirely by the accumulation of CD28- T cells and many of these expressed activation markers human lymphocyte antigen-DR, CD38 and CD45RO on their membrane and molecules such as TIA-1 and perforin, associated with cytolytic function, in their cytoplasm. The strong positive correlation (r = 0.66) between the lack of CD28 expression and the poor proliferation from HIV-1-positive individuals was confirmed by demonstrating that only CD28+ cells transformed into lymphoblasts and proliferated. Although the CD28- including CD3+ T cells transiently expressed CD25 (interleukin-2R alpha), they did not undergo blastogenesis or activation measured by bromodeoxyuridine uptake and died after 3-4 days in culture. These observations were confirmed in costimulation experiments with anti-CD2 and anti-CD28. CONCLUSION: In HIV-1 infection activated CD3+CD28- T cells accumulate but are unresponsive to mitogens and anti-CD28. These cells appear to represent terminally differentiated effector cells which fail to respond to further stimuli because of the absence of a CD28 second signal.

Adult↗
PubMed1994

Flow cytometric analysis of the stimulatory response of T cell subsets from normal and HIV-1+ individuals to various mitogenic stimuli in vitro.

A novel technique is described which allows the study of the responses of T cell subpopulations stimulated in bulk cultures without interfering with cell-cell interactions. The number and phenotype of lymphoblasts developing following stimulation with phytohaemagglutinin (PHA), anti-CD3, staphylococcal protein A (SPA) and pokeweed mitogen (PWM) was determined in HIV-1- and HIV-1+ patients using a new five-parameter flow cytometric method. We found that normal T cells responded faster to PHA than to any of the other mitogens tested. The peak of the PHA response occurred on day 3, followed by anti-CD3 and SPA on day 4 and PWM mitogen on day 5. Although PHA and anti-CD3 stimulated up to 95% and 80% of lymphocytes, respectively, SPA and PWM stimulated only 40% and 30% of cells, respectively. A defective T cell response was observed in lymphocytes cultured from asymptomatic HIV-1+ patients compared with negative controls. This loss of response was related to a selective mortality of T cells following mitogenic stimulation, referred to as activation-associated lymphocyte death (AALD). The results showed that stronger mitogens (PHA and anti-CD3) induced AALD in a larger proportion (50-60%) of T cells than weaker mitogens such as SPA and PWM (30-40%), and that AALD affected different lymphocyte subsets to different extents. AALD occurred more frequently in total CD8+ and CD45RO+ T cells compared with CD4+ and CD45RA+ T cells, but memory CD4+ T cells were the population most severely affected in samples from HIV-1+ donors.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Recurrence rate after accessory pathway ablation.

OBJECTIVE: To evaluate characteristics of patients and accessory pathways as well as additional technical factors involved in the reappearance of accessory pathway conduction after successful ablation. DESIGN: Analysis of recurrences after radiofrequency ablation. SETTING: 163 consecutive patients with 167 accessory pathways. SUBJECTS: 97 men and 66 women with a mean (SD) age of 36 (14) range (11 to 75) years. RESULTS: After a mean (SD) follow up of 14 (7) range (2 to 27) months, conduction recurred in 13 out of 167 (7.8%) accessory pathways. The initial manifestation of recurrence was circus movement tachycardia in 7 patients and reappearance of delta waves on a 12 lead electrocardiogram in 6 patients. The interval to the return of accessory pathway conduction ranged from 3 hours to 90 days. Age, sex, presence of multiple accessory pathways, criteria to determine the target ablation site, number and duration of radiofrequency applications, and cumulative energy did not significantly differ between the groups with recurrence and without. Recurrence was less common with concealed accessory pathways (2/44) than with overt accessory pathways (11/110). The difference was not significant. The only variable to influence the recurrences in this study group was the location of the accessory pathway. Reappearance of conduction through right sided accessory pathways occurred significantly more often than through left sided ones (8/40 v 5/114, P = 0.01). CONCLUSION: After radiofrequency ablation the recurrence rate of accessory pathways is low and there are no predictors of the risk of reappearance of conduction apart from the right sided location of the accessory pathway.

Adolescent↗