Scielo RSS <![CDATA[Revista médica de Chile]]> http://www.scielo.cl/rss.php?pid=0034-988720050004&lang=es vol. 133 num. 4 lang. es <![CDATA[SciELO Logo]]> http://www.scielo.cl/img/en/fbpelogp.gif http://www.scielo.cl <![CDATA[<B>Polimorfismo G691S, L769L y S836S del proto-oncogen RET no se asocian a mayor riesgo de cáncer medular tiroideo esporádico en pacientes chilenos</B>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0034-98872005000400001&lng=es&nrm=iso&tlng=es Background: Medullary thyroid carcinoma (MTC) may occur either as sporadic or as hereditary. Even though the sporadic form corresponds to the majority of cases, the pathogenesis is still unclear. Several polymorphisms of the ret proto-oncogene, including those located in exon 11, 13, 14 and 15 have been described in the general population and some of them seem to be over-represented in sporadic MTC patients from European countries, especially G691S, L769L and S836S. Aim: To evaluate the allele frequencies of these variants in Chilean patients and controls and to determine if these polymorphisms would be associated with the development of sporadic MTC from a different genetic population base. Subjects and Methods: Fifty sporadic MTC patients and 50 normal subjects were tested for G691S, L769L, S836S and S904S polymorphisms. The extracted genomic DNA was initially analyzed by direct sequencing of PCR products in patients. The presence or absence of each polymorphism was also assessed in patients and in control by restriction digestion. Results: The allele frequencies showed a similar level of the G691S, L769L and S904S variants in both groups. Of interest, we found an under-representation of S836S polymorphism in the sporadic MTC group but this number was not statistically significant (p=0.141). Conclusions: We did not find an over representation of the G691S, L769 and S836S. These results argue against the validity of the association of these polymorphisms as contributing factors in the development of sporadic MTC based on a Chilean population and raise questions about the importance of these polymorphisms overall <![CDATA[<B>Tratamiento endovascular del trauma de aorta descendente </B>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0034-98872005000400002&lng=es&nrm=iso&tlng=es Background: Mortality of traumatic aortic lesions is over 80%. A group of those who survive, develop a chronic pseudo aneurism, usually asymptomatic, that is detected during imaging studies. Since conventional surgical treatment of traumatic aortic lesions has a great mortality, endovascular treatment has been used as an alternative treatment in the last decade. Aim: To report our experience with endovascular treatment of traumatic aortic lesions. Patients and methods: Report of seven patients aged 22 to 65 years, with traumatic aortic lesions. Under general anesthesia an endovascular prosthesis was inserted through the femoral artery. Results: No complications were observed in the postoperative period, and after a follow up ranging from 4 to 40 months, no endoleaks or other complications have been detected. Conclusions: Endovascular treatment of traumatic aortic lesions has good immediate and midterm results <![CDATA[<B>Frecuencia y características de la resistencia a aspirina en pacientes cardiovasculares chilenos</B>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0034-98872005000400003&lng=es&nrm=iso&tlng=es Background: Studies performed in Anglo-Saxon countries show that 5% of patients are resistant to the antiplatelet effects of aspirin. Aim: To assess the prevalence of aspirin resistance in a sample of Chilean cardiovascular patients and its association with clinical and laboratory characteristics. Patients and Methods: Ninety nine patients (30 women, 63±10 years) treated for stable cardiovascular diseases with aspirin 100-325 mg/day were studied. Clinical and basic coagulation variables were assessed. Platelet aggregation was studied with platelet rich plasma using three different agonists in an optical aggregometer. Aspirin resistance was defined as an aggregation 20% with arachidonic acid and an aggregation 70% with ADP or collagen. Results: Eleven patients (11.11%, 95% CI= 4.95-17.27%) complied with both criteria and were classified as aspirin resistant. Current smoking was more common in aspirin resistant patients (63.6 vs 29.6%, p=0.039). Conclusions: Aspirin resistance was found in a significant proportion of cardiovascular patients and was more common among current smokers <![CDATA[<B>Estudio de la actividad comparativa <I>in vitro</I> de telitromicina en patógenos respiratorios adquiridos en la comunidad en 13 centros clínicos chilenos </B>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0034-98872005000400004&lng=es&nrm=iso&tlng=es Background: Telithromycin is a new ketolide antimicrobial, that can be useful for the treatment of respiratory infections. Aim: To compare in vitro activity of telithromycin against respiratory pathogens, isolated in outpatient clinics. Material and methods: Two hundred eighty strains isolated from patients with respiratory infections, were studied. The strains studied were S pneumoniae, penicillin sensitive (SPNS:57); intermediate (SPNI:35), resistant (SPNR:25); S pyogenes (SP:57); H influenzae (HIN 51); M catarrhalis (MC:25) and S aureus meticillin sensitive (SAUS:30). Minimal inhibitory concentration (MIC) by broth microdilution was studied for telitrhomycin and levofloxacin in all strains. Other antimicrobials studied, but not in all strains were erythromycin, clindamycin, trimetoprim sulphamethoxazole, oxacillin, amoxicillin-clavulanic acid and cefuroxime. Results: All strains were sensible to telithromycin at a concentration ­4 µg/ml. MIC 90 and its range for SPNS was 0.03 µg/ml (­0.004-0.12), for SPNI was 0.03 µg/ml (­0.004-025), for SPNR was 0.06 µg/ml (­0.004-0.25), for HIN was 2 µg/ml (0.12-4), for SP was 0.5 µg/ml (­0.004-2), for MC was 0.5 µg/ml (0.06-2) and for SAU was 0.25 µg/ml (0.06-0.25). Conclusions: All studied pathogens were sensible to telithromycin in vitro. This antimicrobial is an alternative for the treatment of community acquired respiratory infections <![CDATA[<b>Prevalencia y presencia de factores de riesgo de leptospirosis en una población de riesgo de la Región Metropolitana</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0034-98872005000400005&lng=es&nrm=iso&tlng=es Background:Leptospirosis is a zoonotic disease and its incidence is known in Chile since 2002, when it was incorporated as a disease that must be reported to health authorities. A serologic survey for leptospirosis was performed in humans and animals from a farm in a semi urban area in Santiago Chile, after the death of a farmer due to Weil disease in that place. Aim: To report the prevalence of antibodies against leptospirosis and to determine exposure to infection risk factors in the humans and domestic animals studied in this survey. Material and methods: Antibodies were detected by IgM immunodot and indirect haemagglutination test in 61 humans (43 male, aged 5 to 70 years) and by microscopic agglutination test (MAT) in 44 animals. A questionnaire was applied to determine their exposure to risk factors for infection with Leptospira. Results: Seventy two percent of the studied population were farm workers and 70% had activities that required contact with water from canals, 41% cleaned closed places where rodents were present. Other risk factors detected were lack of sewage and waste disposal, high level of rodent infestation and disposal of faeces into canals used for watering. Two humans (3.3%) and six animals (1 bovine and 5 rodents) had positive antibodies. Among animals, antibodies against Leptospira serovar pomona and icterohaemorragiae were detected. Conclusions: In Chile, leptospirosis exists not only in rural areas but semi urban ones close to Santiago, although the prevalence is low. Education is necessary among semi urban population to avoid infection <![CDATA[<b>Concordancia de lesiones histológicas en ratones infectados por dos poblaciones de <i>Trypanosoma cruzi</i> de Chile</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0034-98872005000400006&lng=es&nrm=iso&tlng=es The great variability in the clinical presentation of Chagas disease may depend in part in the genetic variability of Trypanosoma cruzi populations. Aim: To compare prepatent period, parasitemia, mortality and histological lesions in mice infected with two populations of Trypanosoma cruzi isolated in Chile. Material and methods: Two Trypanosoma cruzi populations, isolated from Chilean Triatomides and genetically characterized by kinetoplast restriction fragment DNA profiles, were compared. Two groups of 40 Balb/c mice were studied. Each mouse was inoculated with 10(4) trypomastigotes, of the V-121 and sp COMB 2 Trypanosoma cruzi populations. The prepatent period, parasitemia, mortality and histopathological lesions, at different evolutionary stages of infection were registered during 32 days. Results: Prepatency and mortality were similar in both groups of mice. However, parasitemia was significantly greater in mice inoculated with V-121 than those inoculated with sp COMB 2. Amastigote pseudocysts and inflammation were present only in skeletal muscle and myocardium in both groups of mice. The intensity of tissue involvement was associated to the level of parasitemia, therefore it was greater in mice inoculated with V-121 population. Conclusions: V-121 population of Trypanosoma cruzi caused a greater parasitemia than COMB 2, in inoculated mice <![CDATA[<B>Análisis crítico de ensayos clínicos randomizados publicados en revistas biomédicas chilenas</B>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0034-98872005000400007&lng=es&nrm=iso&tlng=es Background: Well designed clinical trials yield the strongest evidence for the effect of health care interventions. Aim: To assess the methodological quality of the design and report of randomized clinical trials in a sample, published in biomedical Chilean journals between 1980 and 2002. Material and methods: All trials identified by hand search by the Unit of Evaluation of Technologies in Health, were assessed for quality of randomization, blinding, analysis of results and other characteristics of trial design, along with the application of Jadad's Score, that assesses the methodological quality of clinical trials in a scale that ranges from 0 to 5. Results: Twenty eight trials were found and assessed, 75% (n=21) specified the method used for randomization, 29% (n=8) described a correct allocation concealment and 39% (n=11) were double blinded. Withdrawals and dropouts were correctly reported in 21% (n=6) of the articles, whereas intention to treat analysis was done only in one. Thirteen trials had a Jadad score equal or higher than 3 points. Conclusions: Several design deficiencies were found in the trials assessed. It is difficult to know if methodological weaknesses are due to incomplete reports or to methodologically poor designs. Adopting initiatives like the CONSORT can help improve the quality of randomized clinical trials published in Biomedical Chilean journals <![CDATA[<b>Hemicraniectomía descompresiva en dos pacientes con infarto maligno de la arteria cerebral media</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0034-98872005000400008&lng=es&nrm=iso&tlng=es Malignant middle cerebral territory infarction represents 5 to 10% of all brain infarctions. Its mortality is 80%, due to brain herniation and it is not reduced by medical treatment. Decompressive hemicraniectomy reduces mortality to 12%, and the subsequent quality of life of patients is acceptable. We report two male patients aged 61 and 54 years, with a malignant middle cerebral territory infarction who were treated with decompressive hemicraniectomy. After two years of follow up, both patients are self-sufficient and live at home with their families <![CDATA[<b>Infarto encefálico por embolia aérea</b>: <b>Caso clínico</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0034-98872005000400009&lng=es&nrm=iso&tlng=es Ischemic stroke due to embolic air is uncommon. There are few reports of patients with air embolic stroke as a complication of endoscopic procedures. The temporal relationship between the stroke and this procedure is the most important clue for the diagnosis. CT scan and MRI of the brain are confirmatory tests. The morbidity and mortality is high. Patients should be hospitalized in a critical care service and treated as soon as possible with oxygen in a pressure camera. We report a 52 years old woman with an ovarian cancer that, during an upper gastrointestinal endoscopy, had a severe alteration of consciousness that did not respond to the use of Flumazenil. A CT scan showed multiple areas of air embolism in the watershed area between anterior and middle right cerebral arteries. A conservative treatment was decided and the patients died 48 hours later <![CDATA[<b>Leucemia de células <i>natural killer</i></b>: <b>Caso clínico</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0034-98872005000400010&lng=es&nrm=iso&tlng=es Natural killer leukemia is a rare and highly aggressive neoplasm, is more common in young male patients and has a very poor prognosis, with a median survival of few weeks. We report a 17 years old male patient who developed, after an acute upper respiratory disease, a rapidly multiorganic failure with pancytopenia. Bone marrow aspiration and trephine biopsy showed an acute lymphoblastic leukemia. The immunophenotype and immunohistochemistry revealed a natural killer acute leukemia. The disease progressed rapidly and the patient died shortly after the diagnosis <![CDATA[<b>Etnia mapuche y condiciones socioeconómicas en la estatura del adulto</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0034-98872005000400011&lng=es&nrm=iso&tlng=es Background:Studies in Chilean adults of low socioeconomic level suggest that their low height is likely to be due to their indigenous background. However this group also has been marginalized from socioeconomic development. Aim: To determine the influence of Mapuche ethnic origin and socioeconomic factors on the height of adults. Subjects and methods: In a cross sectional design, the height of 1,293 adults (528 males and 765 females) of Mapuche and non Mapuche origin were studied in the Araucania Region (Southern Chile) and in the Metropolitan Region (Central Chile). Subjects with Mapuche surnames were considered as pertaining to this ethnic community and those with Spanish surnames were considered as non Mapuche. Linear regression models were done, stratifying by sex, considering ethnic origin, to live in counties of different social vulnerability, and the level of family poverty. Results: Among males, the mean height was 166.6±7.3 cm and among females, the figure was 153.6±5.9 cm. Mapuche subjects were significantly shorter: -3.2 cm (95% Confidence Interval (CI) -4.0 to -2.3) among females and -4.8 cm (CI -6.0 to -3.6) among males (non adjusted models). This deficit increased to -4.5 and -7.6 cm among females and males, respectively when they lived in poverty and in areas with highest social vulnerability. These differences decreased significantly if Mapuche subjects lived in communities with low social vulnerability and less poverty (-0.59 and -1.14 cm among females and males respectively). Conclusions: The studied population had low height, being lower in Mapuche subjects. The differences decreased among subjects living in counties of less vulnerability and less family poverty <![CDATA[<b>Mecanismos moleculares en el daño por isquemia-reperfusión hepática y en el preacondicionamiento isquémico</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0034-98872005000400012&lng=es&nrm=iso&tlng=es Ischemia-reperfusion (IR) liver injury is associated with temporary clamping of hepatoduodenal ligament during liver surgery, hypoperfusion shock and graft failure after liver transplantation. Mechanisms of IR liver injury include: i) loss of calcium homeostasis, ii) reactive oxygen and nitrogen species generation, iii) changes in microcirculation, iv) Kupffer cell activation, and (v) complement activation. Pre-exposure of the liver to transient ischemia increases the tolerance to IR injury, a phenomenon known as hepatic ischemic preconditioning (IP). IP involves: i) recovery of the energy supply and calcium, sodium and pH homeostasis, ii) enhancement in the antioxidant potential, and iii) expression of multiple stress-response proteins, including acute phase proteins, heat shock proteins, and heme oxygenase. These observations and preliminary studies in humans give a rationale for the assessment of IP in minimizing or preventing IR injury during surgery and non surgical conditions of tissue hypoperfusion <![CDATA[<b>Variabilidad y variantesde la enfermedad de Alzheimer </b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0034-98872005000400013&lng=es&nrm=iso&tlng=es The heterogeneity and variants of Alzheimer disease (AD) are reviewed. There are cases with a slow or fast evolution and with early or late onset. Most cases are sporadic but there are also hereditary forms. About 50% of patients show neuropsychiatric disorders (depression and psychoses). Some cases have a greater deficit of right or left hemispheric functions. Among the variants, there are forms that start as pure aphasias, predominantly prefrontal cases and posterior cortical forms. Occasionally AD may simulate other disorders such as supranuclear palsy, corticobasal ganglionar degeneration and Jacob-Creutzfeldt disease. Finally, there are mixed forms, in which AD is associated with cerebrovascular disease (very commonly) and with other diseases such as dementia with Lewy bodies. We conclude that AD is a heterogeneous disorder and, therefore, clinical diagnosis may be insufficient. Biological markers and specific imaging studies are needed for a correct clinical diagnosis <![CDATA[<b>Habilitación profesional. Condiciones para el aseguramiento de la calidad de la educación médica y condiciones para la confianza recíproca</b>: <b>Experiencia y visión de ASOFAMECH</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0034-98872005000400014&lng=es&nrm=iso&tlng=es The heterogeneity and variants of Alzheimer disease (AD) are reviewed. There are cases with a slow or fast evolution and with early or late onset. Most cases are sporadic but there are also hereditary forms. About 50% of patients show neuropsychiatric disorders (depression and psychoses). Some cases have a greater deficit of right or left hemispheric functions. Among the variants, there are forms that start as pure aphasias, predominantly prefrontal cases and posterior cortical forms. Occasionally AD may simulate other disorders such as supranuclear palsy, corticobasal ganglionar degeneration and Jacob-Creutzfeldt disease. Finally, there are mixed forms, in which AD is associated with cerebrovascular disease (very commonly) and with other diseases such as dementia with Lewy bodies. We conclude that AD is a heterogeneous disorder and, therefore, clinical diagnosis may be insufficient. Biological markers and specific imaging studies are needed for a correct clinical diagnosis <![CDATA[<b>Juan Pablo II en la Academia Chilena de Medicina</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0034-98872005000400015&lng=es&nrm=iso&tlng=es The heterogeneity and variants of Alzheimer disease (AD) are reviewed. There are cases with a slow or fast evolution and with early or late onset. Most cases are sporadic but there are also hereditary forms. About 50% of patients show neuropsychiatric disorders (depression and psychoses). Some cases have a greater deficit of right or left hemispheric functions. Among the variants, there are forms that start as pure aphasias, predominantly prefrontal cases and posterior cortical forms. Occasionally AD may simulate other disorders such as supranuclear palsy, corticobasal ganglionar degeneration and Jacob-Creutzfeldt disease. Finally, there are mixed forms, in which AD is associated with cerebrovascular disease (very commonly) and with other diseases such as dementia with Lewy bodies. We conclude that AD is a heterogeneous disorder and, therefore, clinical diagnosis may be insufficient. Biological markers and specific imaging studies are needed for a correct clinical diagnosis <![CDATA[<b>Valoración y conducta ante la sordera súbita vista desde un Servicio de Urgencia</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0034-98872005000400016&lng=es&nrm=iso&tlng=es The heterogeneity and variants of Alzheimer disease (AD) are reviewed. There are cases with a slow or fast evolution and with early or late onset. Most cases are sporadic but there are also hereditary forms. About 50% of patients show neuropsychiatric disorders (depression and psychoses). Some cases have a greater deficit of right or left hemispheric functions. Among the variants, there are forms that start as pure aphasias, predominantly prefrontal cases and posterior cortical forms. Occasionally AD may simulate other disorders such as supranuclear palsy, corticobasal ganglionar degeneration and Jacob-Creutzfeldt disease. Finally, there are mixed forms, in which AD is associated with cerebrovascular disease (very commonly) and with other diseases such as dementia with Lewy bodies. We conclude that AD is a heterogeneous disorder and, therefore, clinical diagnosis may be insufficient. Biological markers and specific imaging studies are needed for a correct clinical diagnosis <![CDATA[<b>Fe de Erratum</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0034-98872005000400017&lng=es&nrm=iso&tlng=es The heterogeneity and variants of Alzheimer disease (AD) are reviewed. There are cases with a slow or fast evolution and with early or late onset. Most cases are sporadic but there are also hereditary forms. About 50% of patients show neuropsychiatric disorders (depression and psychoses). Some cases have a greater deficit of right or left hemispheric functions. Among the variants, there are forms that start as pure aphasias, predominantly prefrontal cases and posterior cortical forms. Occasionally AD may simulate other disorders such as supranuclear palsy, corticobasal ganglionar degeneration and Jacob-Creutzfeldt disease. Finally, there are mixed forms, in which AD is associated with cerebrovascular disease (very commonly) and with other diseases such as dementia with Lewy bodies. We conclude that AD is a heterogeneous disorder and, therefore, clinical diagnosis may be insufficient. Biological markers and specific imaging studies are needed for a correct clinical diagnosis