Scielo RSS <![CDATA[Revista médica de Chile]]> https://scielo.conicyt.cl/rss.php?pid=0034-988720080001&lang=es vol. 136 num. 1 lang. es <![CDATA[SciELO Logo]]> https://scielo.conicyt.cl/img/en/fbpelogp.gif https://scielo.conicyt.cl <![CDATA[<b>Valor pronóstico del nuevo sistema de etapificación internacional en mieloma múltiple</b>: <b>Comparación con el sistema de Durie-Salmon</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872008000100001&lng=es&nrm=iso&tlng=es Background: Since 1975, the Durie-Salmon staging system (D&S) has been a widely accepted prognostic classification of multiple myeloma (MM) patients. Recently, the new International Staging System (ISS) was developed using only the values of albumin and betaZ-microglobulin. Aim: To compare survival of patients with MM treated in six medical centers in Chile according to the D&S system and the new ISS. Material and methods: Retrospective analysis of demographic information, clinical features and survival rate of patients treated between 1998 and 2002, and grouped according to both systems. Results: Information of 81 patients aged 38 to 90 years (43 women) was retrieved. According D&S system 11% were in stage I 12% in stage II and 73% in stage III According to ISS, 34% were in stage I 35% in stage II and 31% in stage III Median of survival of all patients was 32 months. Both staging systems had a prognostic value. However, median survival for the three stages of the ISS system was significantly different (67, 29 and 14 months in stages III and III, respectively, p =0.02). Patients in advanced stages II and III of the ISS, had a higher frequency of anemia, hypercalcemia, renal failure and hypoalbuminemia. In stages II and III of ISS the presence of renal failure was associated with a non significantly different lower survival. Conclusions: The ISS is a simple and effective grouping method for patients with MM, that predicts survival. The presence of renal insufficiency might identify a subgroup of patients included in stages II and III of ISS with a higher mortality (Rev Méd Chile 2008; 136: 7-12) <![CDATA[<b>Evaluación de un programa piloto de intervención en adultos con sobrepeso u obesidad, en riesgo de diabetes</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872008000100002&lng=es&nrm=iso&tlng=es Background: The Ministry of Health of Chile and selected obesity specialized centers implemented an interdisciplinary pilot program for overweight adults at risk of diabetes to decrease the risk of type 2 diabetes (T2D) and cardiovascular risk factors (CVRF). Aim To assess the results of this program. Patients and methods: Beneficiaries of the public primary health system aged 18-45 years, with a body mass index (BMI) 25-38 kg/m² and fasting blood glucose 100-125 mg/dL or with any direct family member with T2D, were recruited. During the four months of the study, they were scheduled for three physician visits, four dietitian consultations, 14 physical activity sessions and four group workshops (two with a psychologist or therapist). In fasting blood samples, at the beginning and at the fourth month, glucose, insulin and lipids were determined. The Homeostasis model assessment (HOMA) index was calculated. Results: Two hundred-seventy-six patients were recruited and 160 (141 women), completed the four months of follow up. In this subgroup, at the start and end of the intervention, a BMI equal to or greater than 30 kg/m² was observed in 69% and 52% of subjects respectively, a systolic blood pressure equal to or greater than 140 mm Hg was observed in 24% and 6% respectively, a diastolic blood pressure equal to or greater than 90 mm Hg was observed in 28% and 9% respectively, a blood glucose equal to or greater than 100 mg/dL was observed in 61% and 19% respectively, a plasma insulin equal to or greater than 12,5 fi Ul/rnl was observed in 49% and 34% respectively and a HOMA equal to or greater than 2.5 was observed in 63% and 42% respectively (all these comparisons are significant with a p <0.05). Conclusions: In those patients that completed the follow up period, this intervention induced a significant decrease of some CVRF, such as BMI, fasting glucose levels and HOMA index (Rev Méd Chile 2008; 136:13-21) <![CDATA[<b>Efectividad de una intervención en educación alimentaria y actividad física para prevenir obesidad en escolares de la ciudad de Casablanca, Chile (2003-2004)</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872008000100003&lng=es&nrm=iso&tlng=es Background: With the aim of contributing to he Healthy Goal 2010 of reducing significantly the prevalence of childhood obestiy we developed and implemented during 2003 and 2004, a school-based obesity prevention intervention which included nutrition education and the promotion of physical activity. Aim To report the results of the intervention. Material and methods: The sample included 1760 children (1st to 7th grade) from 3 elementary public schools in Casablanca (experimental group) and 671 from a similar school located in Quillota, a neighboring city (control). Primary outcomes were body mass index (BMI) Zscore, the mile and shuttle-run tests and obesity prevalence. We also compared changes in waist circumference and triceps skinfold between both groups. Effectiveness of the intervention was assessed by analyzing separately the group *age* time interaction for the first 3 outcomes (follow-up-baseline), using a mixed model of covariance and by comparing variations in obesity prevalence between both groups. Results: There was a significant decline in BMI Z scores in experimental schools for both genders, but greater in boys (p <0.001 versus p =0.0034 in girls), while in controls, BMI Z scores increased. Obesity prevalence declined significantly in experimental schools; from 17 to 12.3% and from 14.1 to 10.3% in boys and girls respectively, while in the control group, it remained unchanged. Also, triceps skinfold in girls from Casablanca increased significantly ¡ess than that of control girls. Conclusion: This intervention proved that it is possible to reduce significantly the prevalence of obesity in Chilean schoolchildren attending public elementary schools (Rev Méd Chile 2008, 136:22-30) <![CDATA[<b>Cirugía de la endocarditis infecciosa en un centro regional en Chile</b>: <b>Análisis de casos y resultados en el largo plazo</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872008000100004&lng=es&nrm=iso&tlng=es Background: Surgery for active endocarditis is indicated in cases of congestive heart failure (CHF), persistent sepsis, systemic embolization and paravalvular involvement. Aim: To assess and report the long term results of surgery in adult patients. Patients and methods: Retrospective review of clinical records and operative procedures of 32 patients aged 43± 13 years (28 women) subjected to reparative surgery for complications of endocarditis between 1993 to 2005. Results: In 25% of cases, endocarditis presented as a prolonged sepsis syndrome and in 31% as a CHF or both. The causative bacteria was Gram (+) in 53% and blood cultures were negative in 47%. Preoperative echocardiography showed vegetations in 56% of cases. An annular abscess, aortic valve rupture and bicuspid valve, was observed in 13% of patients. Post operative mortality was due to persistent sepsis and multiorganic dysfunction in 16%. Mean long term follow up was 43.8±47.2 months. Actuarial survival was 78% at 146 months. Conclusion: Surgical management of active endocarditis provides a good symptomatic recovery, with an excellent long term actuarial survival (Rev Méd Chile 2008; 136: 31-7) <![CDATA[<b>Abscesos esplénicos</b>: <b>Comunicación de siete casos y revisión de la literatura</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872008000100005&lng=es&nrm=iso&tlng=es Background: Splenic abscesses are uncommon, appear in subjects with predisposing factors such as systemic infections and have high mortality rates. Aim: To report seven patients with splenic abscesses. Material and Methods: Retrospective review of medical records of patients with a splenic abscess treated between 1987 and 2005. Results: The records of four women and three males aged 20 to 74 years, were reviewed. The most common presenting symptoms were fever and abdominal pain and all had predisposing factors. Six patients had a leukocyte count of 19,500 x mm³. Mean erythrocyte sedimentation rate and C reactive protein values were 75 mm/h and 13.5 mg/dl. Diagnosis was made with ultrasound in two patients and CT scan in five. Six patients had an unique abscess and one patient had multiple lesions. A splenectomy was done in three patients as the first choice treatment and in one, due to medical treatment failure. In two patients, a CT guided percutaneous drainage was performed and one patient was subjected to medical treatment only. Abscess cultures were positive in 50% of patients subjected to percutaneous drainage and in 50% of splenectomized patients. No patient died and no complications were observed in the early or ¡ate postoperative period. Conclusion: Splenic abscesses are associated to predisposing conditions. The first choice is surgical treatment, but percutaneous drainage is also a therapeutic option (Rev Méd Chile 2008; 136: 38-43) <![CDATA[<b>Prevalencia y factores de riesgo asociados a la depresión posparto en puérperas de un Centro de Atención Primaria en el Sur de Chile</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872008000100006&lng=es&nrm=iso&tlng=es Background: Mood disorders are common in Chile. Among these, post partum depression (PPD) deranges the maternal and family relationships. Aim: To determine the prevalence and risk factors associated with PPD in puerperal women in Temuco, Chile. Material and methods: The Edinburgh Postnatal Depression Scale was administered to 73 puerperal women aged 15 to 32 years, between 40 to 45 days after delivery. To detect risk factors, 20 women with and 20 women without post partum depression (PPD) were interviewed and their clinical records were reviewed to assess their perinatal care. Results: The prevalence of PPD in the whole sample was 50.7%. The individual psychological risk factors detected were a feeling of discomfort with their body after giving birth, a personal history of mental health problems and a high level of overload associated to child care. An individual physical risk factor was alcohol consumption during pregnancy. Family risk factors were a poor relationship with the father of the child during pregnancy, a history of mental health problems in close family members, a history of family violence and a poor realtionship with parents during puerpurium. Having more children was a sociodemographic risk factor. Conclusions: Pospartum depression is common. The characterization of risk factors should lead to the implementation of preventive strategies (Rev Méd Chile 2008; 136: 44-52) <![CDATA[<b>Hábitos de ingesta y actividad física en escolares, según tipo de establecimiento al que asisten</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872008000100007&lng=es&nrm=iso&tlng=es Background: The increased infantile obesity rates are related to faulty dietary intake (DI) and physical activity (PA) habits, that are probably related to a prolonged stay at school during the day. Aim: To investigate DI and PA among elementary and high school students and their association with type of school that they attend. Material and Methods: Quality of DI and PA was assessed, using specially designed questionnaires, in 1136 elementary school and 1854 high school children attending public schools managed by city halls (ME), subsidized private (SE) and private (PE) of the Metropolitan Region. The responses to the questionnaires, were qualified using a numeric scale that ranged from 0 to 10 points. A higher score indicated a better habit. Results: Percentile 25 (p 25 th) PA score was 4 and 3 in elementary and high school children respectively and the p 25 th for DI were 5.7 and 4.3, respectively. No differences in DI scores, according to the type of school, were observed. However, physical activity scores were significantly lower in children and adolescents from ME schools than from PE schools. Sixty percent of ME schools had ¡ess than 2 hours per week of programmed physical activity compared to more than 3 hours, in 70% of PE schools. Elementary school children and high school adolescents expended 8 and 11 hours per day, respectively, in minimum expenditure activities. Conclusions: There is a greater deterioration of PA than DI among school age children and adolescents. Those attending ME schools have the worst physical activity scores. This fact must be addressed in future healthy lifestyle encouragement policies (RevMéd Chile 2008; 136: 53-63) <![CDATA[<b>Actividad supresora del millerenólido sobre células mononucleares de sangre periférica humana</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872008000100008&lng=es&nrm=iso&tlng=es Background: Natural products are used in the production of therapeutic drugs due to their wide diversity and excellent adaptability to biological structures. Sesquiterpene ¡aciones are the active constituents of several plants from the Asteraceae family. Aim: To assess the in vitro effect of a sesquiterpene lactone (millerenolide). Material and methods: The drug effect was assessed measuring the proliferation of lymphocytes using the 2,3-bis (2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino) carbonylJ-2H-tetrazolium hydroxide (XTT) technique. Changes on the cell cycle were analyzed on a FACSort flow cytometer The effect of millerenolide on the production of nitric oxide (NO) by macrophages was evaluated using the Griess reagent. Additionally, phagocytosis of latex particles and nitroblue tetrazolium (NBT) reduction by macrophages were evaluated microscopically. Results: Treatment of human peripheral blood mononuclear cells (PBMC) with millerenolide decreases the proliferation of lymphocytes, decreases the percentage of cells in S, and G2/Mphases, and increases the proportion of cells in GO/Gl phase. Treatment of macrophages with millerenolide, reduces the production of NO, the phagocytic capacity and the number of cells able to reduce NBT. Cytotoxic effects of the lactone on human PBMC were only observed when the concentration was increased to 6 fig/ml. Conclusions: Millerenolide could be considered as a potential therapeutic agent with immunosuppressiveproperties (RevMéd Chile 2007; 135: 64-72) <![CDATA[<b>Expectativas en el consumo de alcohol en Bucaramanga, Colombia</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872008000100009&lng=es&nrm=iso&tlng=es Background: Expectancies such as memories, motivations and emotions towards alcohol are an important predictor of alcohol consumption in the population. The Alcohol Expectancy Questionnaire (AEQ-III) can measure objectively these expectancies. Aim: To study which expectancies are associated to alcohol consumption in adults living in Bucaramanga, Colombia. Material and methods: The AEQ-III was applied to 601 adults (334 males) aged 18 to 60 years. A binomial regression was used to determine the expectancies that were associated with alcohol consumption after adjusting for social and demographic variables. Results: Eighty nine percent of the population consumes alcohol, without differences by age, gender, body mass index, educational or socioeconomic level. Positive expectancies related to disinhibition and feelings of power with a prevalence ratio (PR) of 1.33 (95% confidence intervals of1.06-1.67) and an age of ¡ess than 16 years when alcohol consumption started, with a PR of 1.15 (95% confidence intervals of 1.08-1.23), were the only two explanatory variables for alcohol consumption. Conclusions: Alcohol comsuption is more associated to social context and group integration than with individual behaviors (Rev Méd Chile 2008; 136: 73-82) <![CDATA[<b>Tiroides lingual como causa de disfagia</b>: <b>Caso clínico</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872008000100010&lng=es&nrm=iso&tlng=es We report all year-old boy who presented with difficulty in swallowing without symptoms of hypothyroidism. The physical examination revealed a mass at the base of the tongue. The thyroid hormone profile showed a primary hypothyroidism (a serum TSH of 10.8 IU/mL with normal-low thyroxin of 6.0 fig/dL and low triiodothyronine of 57.8 ng/ dL). Antithyroid antibodies were negative. The fiberoptic endoscopy showed a reddish mass, without evidence of haemorrhage or ulceration, confirmed as a well circumscribed, hypodense mass in the base of the tongue by computed tomography of the oropharynx and neck. Tc-99-pertechnetate scanning showed an abnormal area of uptake at the base of the tongue and no uptake in the normal thyroid location, concordant with an ectopic lingual thyroid gland. Levothyroxine in a suppressive dose was started that resulted in a reduction of the size of the mass and disappearance of dysphagia (RevMéd Chile 2008; 136: 83-7) <![CDATA[<b>Acidosis láctica severa asociada a infusión de propofol</b>: <b>Caso clínico</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872008000100011&lng=es&nrm=iso&tlng=es Propofol infusion syndrome (PRIS) is a rare but potentially lethal complications. This disorder is triggered under unknown circumstances by a propofol infusion of more than 5 mg/kg/h for more than 48 h. PRIS is characterized by a multiorgan failure and rhabdomyolysis and is induced by a disturbance in mitochondrial long chain fatty acid oxidation. We report a 43 year-old woman who underwent brain surgery due to a vascular malformation. In the immediate postoperative period, she had an unexplained and severe lactic acidosis. During anaesthesia, she received a propofol infusion of 7 mg/kg/h that continued in the UCI at a rate of 3.5 mg/kg/h, for 8 hours more. The suspicion of PRIS motivated immediate discontinuation of propofol with rapid correction of lactic acidosis and full recovery of the patient (Rev Méd Chile 2008; 136: 88-92) <![CDATA[<b>Leucoencefalopatía reversible posterior</b>: <b>cuatro casos clínicos</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872008000100012&lng=es&nrm=iso&tlng=es Reversible posterior leukoencephalopathy syndrome (PLS) is characterized by headache, clouding of sensorium, visual disturbances and seizures. It is associated to hypertension, renal disease or immunosuppressive therapy. We report three males, aged 9, 12 and 16 years and one female, aged 5 years wih PLS associated to immunosuppressive therapy. All had seizures and three had headache and clouding of sensorium. One case was associated to an hypertensive emergency, one to liver failure and one to high tacrolimus levels. Magnetic resonance imaging showed lesions in the white matter in two patients and in the gray matter in the other two. The lapse between the start of immunosuppressive treatment and neurological symptoms ranged from 4 days to 6 months. All received antiepileptic drugs and immunosuppresive therapy was changed or decreased, with complete clinical recovery (Rev Méd Chile 2008, 136: 93-8) <![CDATA[<b>Estado actual de las especialidades médicas en Chile</b>: <b>realidad en el sistema público no municipalizado</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872008000100013&lng=es&nrm=iso&tlng=es To adequately plan the post graduate training of physicians, we need to know the needs for specialists in the country and the most prevalent diseases and causes of consultations. In 2004, the National System of Health Services assessed the number of hours and types of specialities available, their regional distribution and calculated an approximate number of physicians in charge of those specialities, determining an equivalent per 44 weekly hours of physician. This number of hours is the maximum that a physician is allowed to work per week. Fifty six percent of specialists correspond to basic specialities (3,688 physicians equivalent to 44 hours, 33% to primary specialities (2,205 physicians) and 10% to subspecialties (666 physicians). The regional distribution of basic specialties is proportional to the population of each region. However, there are gaps in the distribution of primary specialties and subspecialties. The demand for specialists, assessed measuring the yield in minutes of each hired hour, determined that 54% of specialist hours are delicated to the new health program that guaranties the access to certain specialties in a predefined lapse, to all beneficiaries (AUGE). Moreover the demand for attentions to cover this health system has a gap of 30% in hours or 800 specialists. This motivated the creation of new posts for specialties during 2005 and 2006, equivalent to 250 physicians hired for 44 hours per week (Rev Méd Chile 2008; 136: 99-106) <![CDATA[<b>Objetivos moleculares para diseñar nuevos fármacos para el tratamiento de la diabetes tipo 2 y la obesidad</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872008000100014&lng=es&nrm=iso&tlng=es Current strategies to treat type 2 diabetes (DMT2) include reducing insulin resistance using glitazones, supplementing with exogenous insulin, increasing endogenous insulin production with sulfonylureas and meglitinides, reducing hepatic glucose production through biguanides, and limiting postprandial glucose absorption with alpha-glucosidase inhibitors. In all of these areas, new generations of molecules with improved efficacy and safety profiles, are being investigated. Promising biological targets are rapidly emerging such as the role of lipotoxicity as a cause of glucometabolic insulin resistance, leading to a host of new molecular drug targets such as AMP-activated protein kinase (AMPK) activators, recombinant adiponectin derivatives, and fatty acid synthase (FAS) inhibitors. Insulin action can be enhanced in muscle, liver and fat, with small-molecule activators of the insulin receptor or inhibitors of protein tyrosine phosphatase (FTP)-IB. Defective glucose-stimulated insulin secretion by pancreatic B-cells could be alleviated with recombinant glucagon-like peptide (GLP-1) or agonists to the GLP-1 receptor. This review presents a new approach for obesity and DMT2 drug discovery through pharmacogenomics. Several compounds have already been validated through genetic engineering in animal models or the preliminary use of therapeutic compounds in humans (Rev Méd Chile 2008; 136:107-17) <![CDATA[<b>Historia del protozoo <i>Entamoeba histolytica</i></b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872008000100015&lng=es&nrm=iso&tlng=es This article presents a history of Entamoeba histolytica spanning since the remote times when it was not even recognized as a cause of human disease to the recent molecular advances. Feder Losch (1875) in Saint Petersburg, found amoebae in fecal samples but only regarded them as responsible for maintaining the inflammatory process, not as a cause of dysentery. Fritz Schaudinn (1903) established the differentiation between Entamoeba histolytica and Endamoeba coli, Schaudinn decided to call it E. histolytica because of its ability to cause tissue lysis. Emile Brumpt (1925) based on experimental studies, pointed out the existence ofE. Histolytica as a species complex, comprising two morphologically indistinguishable species, E. dysenteríae which is the cause of symptomatic infection, and Entamoeba dispar found only in asymptomatic carriers. Louis Diamond et al (1961) during the 1960s developed an axenic culture medium for E. histolytica which allowed in vivo and in vitro studies. Sargeaunt and Williams (1978) distinguished for the first time E. histolytica strains by isoenzyme electrophoresis, thus confirming thatE. hystolytica was indeed a species complex comprising both pathogenic and non-pathogenic species. William Petri et al (1987 demonstrated that the 170 kDa protein with greater antigenicity was the Gal/GalNac-specific lectin. Diamond and Clark (1993) described again Brumpt's original 1925hypothesis, concluding that there was enough evidence to support the existence of two morphologically indistinguishable species, a pathogenic and a nonpathogenic one, corresponding to E. histolytica and Entamoeba dispar respectively. The World Health Organization accepted this hypothesis in 1997 (RevMéd Chile 2008; 136:118-24) <![CDATA[<b>Medición en salud</b>: <b>Algunas consideraciones metodológicas</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872008000100016&lng=es&nrm=iso&tlng=es Measurement process is a part of everyday work of health professionals. Technological advances have created precise and sensitive instruments whose results are highly accurate and cast little doubts. However, health care has diversified, becoming a multidimensional and complex task. This means that new aspects, that are difficult to measure, must be addressed, such as health perception by patients or cost usefulness ratios of health actions. Therefore, clinicians and researchers must have a good perception of the quality of measures that they use in their daily work, to make the correct diagnostic, therapeutic or prognostic decisions. This article explores the operational concepts that help in the development and assessment of measuring instruments in terms of validity and truthfulness (Rev Méd Chile 2008; 136: 125-30) <![CDATA[<b>Dr. Camilo Larraín Aguirre (1918-2007)</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872008000100017&lng=es&nrm=iso&tlng=es Measurement process is a part of everyday work of health professionals. Technological advances have created precise and sensitive instruments whose results are highly accurate and cast little doubts. However, health care has diversified, becoming a multidimensional and complex task. This means that new aspects, that are difficult to measure, must be addressed, such as health perception by patients or cost usefulness ratios of health actions. Therefore, clinicians and researchers must have a good perception of the quality of measures that they use in their daily work, to make the correct diagnostic, therapeutic or prognostic decisions. This article explores the operational concepts that help in the development and assessment of measuring instruments in terms of validity and truthfulness (Rev Méd Chile 2008; 136: 125-30) <![CDATA[<b>La importancia del <i>"Feedback"</i></b>: <b>Una vivencia docente</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872008000100018&lng=es&nrm=iso&tlng=es Measurement process is a part of everyday work of health professionals. Technological advances have created precise and sensitive instruments whose results are highly accurate and cast little doubts. However, health care has diversified, becoming a multidimensional and complex task. This means that new aspects, that are difficult to measure, must be addressed, such as health perception by patients or cost usefulness ratios of health actions. Therefore, clinicians and researchers must have a good perception of the quality of measures that they use in their daily work, to make the correct diagnostic, therapeutic or prognostic decisions. This article explores the operational concepts that help in the development and assessment of measuring instruments in terms of validity and truthfulness (Rev Méd Chile 2008; 136: 125-30) <![CDATA[<b>Historia de Chile en la vida de un médico Alfredo Jadresic V. </b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872008000100019&lng=es&nrm=iso&tlng=es Measurement process is a part of everyday work of health professionals. Technological advances have created precise and sensitive instruments whose results are highly accurate and cast little doubts. However, health care has diversified, becoming a multidimensional and complex task. This means that new aspects, that are difficult to measure, must be addressed, such as health perception by patients or cost usefulness ratios of health actions. Therefore, clinicians and researchers must have a good perception of the quality of measures that they use in their daily work, to make the correct diagnostic, therapeutic or prognostic decisions. This article explores the operational concepts that help in the development and assessment of measuring instruments in terms of validity and truthfulness (Rev Méd Chile 2008; 136: 125-30)