Scielo RSS <![CDATA[Revista médica de Chile]]> https://scielo.conicyt.cl/rss.php?pid=0034-988720070011&lang=en vol. 135 num. 11 lang. en <![CDATA[SciELO Logo]]> https://scielo.conicyt.cl/img/en/fbpelogp.gif https://scielo.conicyt.cl <![CDATA[<b><i>Hybrid embryos as a source of embrionic stem cells</i></b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872007001100001&lng=en&nrm=iso&tlng=en The HFEA (Human Fertilisations & Embryology Authority) recently accepted to perform research in hybrid embryos generated by transferring human somatic cell nucleus to cow enucleated oocytes, named cytoplasmatic hybrids. The aim is to obtain a source of embryonic stem cells without the use of human oocytes. The arguments for the approval are to avoid the risk of obtaining human oocytes and that these embryos will not be transferred to a female's womb for its development. Those who oppose the technique argue that it is a manipulation of the beginning of life and a disrespect to the dignity of human life because of the destruction of embryos. Nevertheless, the real nature of this new entity has not been established. Biologically it is an embryo with 99% of human genome and animal's cytoplasm, not generated from human gametes, it is not a new genome and it will be used only to cultivate stem cells. It does not seem possible to define its nature beyond any doubts. If it were considered as a human embryo it should be respected and protected as every human being. Once more, scientific progress opens new ethical and legal questions that we cannot answer in a definitive way. Researchers are exploring new roads to obtain pluripotential stem cells which should favor the development of innovative therapies. The main objection is the unavoidable destruction of human embryos, although in this case its origin and nature are not clear <![CDATA[<b><i>Socioeconomic and educational inequities as independent predictors for mortality in a developing country</i></b>: <b><i>A cohort study in San Francisco, Chile</i></b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872007001100002&lng=en&nrm=iso&tlng=en Background: The socioeconomic position (SEP) and educational level of individuals have an inverse correlation with mortality in developed societies. Aim To assess in a society undergoing a socioeconomic transition, the mortality risk associated to a low SEP (combination of education and income, scale 0-25 points, reference > 10 points) and low education (education years, reference > 8 years), adjusting for other known risk factors. Material and methods: In this prospective cohort study, a random sample of 920 subjects, living in San Francisco de Mostazal, Chile, aged more than 20years (395 males) was examined for the first time in 1997-1999 and re-examined in 2005-2006. All had information about economic household income and level of education. A Cox regression model was used to evaluate the association between mortality and socioeconomic measures. Results: The crude mortality hazard ratio (HR) was 3.34 (95% confidence interval (CI) 2.88-3.87) and 6.05 (95% CI 5.04-7.26) for low SEP and low educational level, respectively. After adjusting for age, gender, hypertension, diabetes, dyslipidemia, abdominal obesity, smoking, alcohol intake and family history of cardiovascular disease, the figures were 1.23 (95% CI 1.04-1.43) and 1.54 (95% CI 1.23-1.85) for low SEP and low educational level, respectively. Conclusions: In a society in socioeconomic transition, low SEP and especially low educational level are risk factors for mortality even after adjusting for known mortality risk factors <![CDATA[<b><i>Treatment of advanced gastric cancer with oxaliplatin plus 5-fluorouracil/ leucovorin (FOLFOX-4 chemotherapy)</i></b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872007001100003&lng=en&nrm=iso&tlng=en Background: Chemotherapy improves survival in advanced gastric cancer. However the most active combinations have a high level of toxicity that limits their use. Aim: To assess the response, toxicity and survival of patients with advanced gastric cancer, treated with oxaliplatin plus 5-fluorouracil/leucovorin (FOLFOX-4 chemotherapy). Material and methods: Patients with stage IVgastric cancer, according to the American Joint Committee on Cancer or with relapsed disease and functional capacity 0-2 of the South West Oncology Group, were included. FOLFOX-4 chemotherapy was used as first or second line treatment. The response to treatment and survival were assessed. Results: Between 2003 and 2006, 29 patients (median age 52.5 years, 69% males) were treated. FOLFOX-4 was given as first line treatment in 65% patients and as second line in 35%. There was a complete response in 4.6%, partial response in 68%, stable disease in 20.6% and progression in 6.8%. Toxicity was observed in 51% of patients, that was hematological and non hematological grade 3/4 in 14%. Median survival was 12.5 months. Conclusions: FOLFOX-4 chemotherapy was active in advanced gastric cancer and had a low level of toxicity <![CDATA[<b><i>Shigella spp Infections In children living In the Metropolitan RegionChile, during summer of 2004-2005</i></b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872007001100004&lng=en&nrm=iso&tlng=en Background: Shigella spp is a frequent cause of diarrhea in children. Antimicrobials decrease the duration of diarrhea and pathogen excretion. However, the increasing resistance limits their therapeutic value. Aim: To study Shigella serotype distribution in the Metropolitan Region in Chile, and its relationship with severity of disease, antimicrobial resistance pattern and clonality. Material and methods: During summer 2004-2005, stool samples from children with diarrhea were collected in Cary Blair transpon medium and cultured. Shigella isolates were serotyped using monoclonal and polyclonal commercial antibodies. In vitro activity of ampicillin, amoxicillin/clavulanic acid, chloramphenicol, cotrimoxazol, nalidixic acid, ciprofloxacin, ceftriaxone and azythromycin was determined by minimal inhibitory concentration (MIC). Clonality was studied by pulsed-field gel electrophoresis (PFGE) using Xbal as restriction enzyme. Results: One hundred thirty nine Shigella strains were isolated (77 S sonnei and 62 S flexneri). S sonnei and S flexneri 2a serotypes were responsible for 95% of episodes. Children aged 2-4 years, showed a greater incidence of Shigella infections and 77% of episodes were treated on an ambulatory basis. High resistance levels were observed for ampicillin, cotrimoxazole, amoxicillin-clavulanic acid and chloramphenicol (67%, 60%, 56% and 45%, respectively). We found 11 resistance patterns and 61,2% of strains were multiresistant. There were multiple clones without a strict relationship with resistance patterns. Conclusions: Shigella infections in Metropolitan Region in Chile are associated to a restricted number of serotypes, representing a clonal expansion associated to different antimicrobial resistant patterns <![CDATA[<b><i>Geographical distribution of mortality caused by stomach, trachea, bronchi and lung malignant tumors in Chile</i></b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872007001100005&lng=en&nrm=iso&tlng=en Background: Maps have played a critical role in public health since 1855, when John Snow associated a cholera outbreak with contaminated water source in London. After cardiovascular diseases, cancer is the second leading cause of death in Chile. Cancer was responsible for 22.7% of all deaths in 1997-2004 period. Aim To describe the geographical distribution of stomach, trachea, bronchi and lung cancer mortality. Material and methods: Mortality statistics for the years 1997-2004, published by the National Statistics Institute and Chilean Ministry of Health, were used. The standardized mortality ratio (SMR) for sex and age quinquennium was calculated for 341 counties in the country. A hierarchical Bayesian analysis of Poisson regression models for SMR was performed. The maps were developed using adjusted SMR (or smoothed) by the Poisson model. Results: There is an excess mortality caused by stomach cancer in south central Chile, from Teno to Valdivia. There is an excess mortality caused by trachea, bronchi and lung cancer in northern Chile, from Copiapó to Iquique. Conclusions: The geographical analysis of mortality caused by cancer shows cluster of counties with an excess risk. These areas should be considered for health care decision making and resource allocation <![CDATA[<b><i>Detection of primary antiretroviral resistance in Chilean patients recently infected with human immunodeficiency virus (HIV)</i></b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872007001100006&lng=en&nrm=iso&tlng=en Background: In countries with universal access to antiretroviral therapy a progressive increase in the number of patients that are infected with resistant virus, is observed. Aim To detect the presence of primary resistance to antiretroviral drugs among patients with a recent diagnosis of HIV infection. Material and methods: Twenty five male patients aged 25 to 45 years, with a diagnosis of a recent HIV infection, done between 2004 and 2005, were studied. Genotypic resistance to antiretroviral drugs was studied using the Genetic Resistance Test TRUGENE® from Bayer. Results: Resistance mutations were detected in 10 patients. All had an university title or had university studies. All lived in northeastern Santiago and had risky sexual behaviors while traveling abroad. Seven mutations were detected in reverse transcriptase. Of these, three were associated to a high resistance level and four, to an intermediate or low resistance, were also detected. Conclusions: A high frequency of genotypic resistance was detected in this group of Chilean patients recently infected with HIV. A higher socioeconomic status and lifestyle could have influenced these results <![CDATA[<b><i>Carotid body tumors</i></b>: <b><i>Report of ten cases</i></b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872007001100007&lng=en&nrm=iso&tlng=en Background: Carotid body tumors arise from a cellular conglomerate located at the carotid bifurcation. Progressive enlargement can involve the arterial wall and neighbor cranial nerves. Aim: To report a series of 10 patients treated of carotid body tumors and review national experience. Patients and methods: Between 1984 and 2006, we operated 8 women and 2 men, aged 19 to 75 years, with this type of tumor. Results: The most common cause for consultation was a cervical mass in 90%, with a mean evolution lapse of 13.2 months (range 3 to 126). In all cases, diagnosis was confirmed with angiographic imaging and histopathology. Ten tumors were surgically removed with no complications. Eighty percent of tumors were in stage II according to Shamblin classification. During long term follow up all patients have remained asymptomatic. Only 31 carotid body tumors have been reported in Chilean medical literature during a 43 year period. Conclusions: Paragangliomas of the carotid body can be diagnosed in clinical grounds, requiring vascular imaging. These infrequent lesions are generally benign, early surgical removal by surgeons with vascular expertise avoids neurological and or vascular complications <![CDATA[<b><i>Treatment of acquired severe aplastic anemia in pediatric patients with immunosupression and allogeneic stem cell hematopoyetic transplant</i></b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872007001100008&lng=en&nrm=iso&tlng=en Background: Severe acquired aplastic anemia (SAA) is an uncommon disease of childhood. Patients with SAA receive supportive care with transfusions and timely treatment of opportunistic infections, along with specific therapies, which may be allogenic stem cell transplantation (SCT) from a matched sibling or immunosupressive therapy (IT). Aim: To report the experience in the management of SAA. Patients and methods: Twenty five children with acquired SAA were treated from July 1992 to September 2005. Patients with full matched sibling donors received allogenic SCT after conditioning with a cyclophosphamide containing regimen. The other patients received immune suppression with cyclosporine plus methylprednisolone (n= 18) plus ATG (n=17). All received supportive care until recovery of hematopoietic function. Those who had severe opportunistic infections at diagnosis or did not respond to two cycles of ATG were evaluated for unrelated donor SCT. Results: Seven patients received sibling donor SCT and 18 IT, which was repeated in six. Three patients received mismatched related (1) or unrelated (2) SCT. Nineteen patients survived with a median follow up time of 4 years, 14 with full hematologic recovery. Six patients died: four due to infections after IT or SCT, one due to intracranial hemorrhage and one with secondary myelodysplasia 12 years after IT. Conclusions: Most children with SAA can be treated successfully with sibling donor SCT or IT. Patients without a histocompatible sibling who fail to respond to IS have a worse prognosis <![CDATA[<b><i>Age of menarche and its relationship with body mass index and socioeconomic status</i></b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872007001100009&lng=en&nrm=iso&tlng=en Background: A decline in the age of menarche was observed from early 1900s to the 1970s. However, it is not known if a further decline ocurred thereafter. Aim: To evaluate the age of menarche in girls from Santiago, Chile and its relationship with body mass index (BMI) and socioeconomic status. Material and Methods: We studied 1302 healthy girls aged 7 to 19 years. Age of menarche was evaluated through a questionnaire to the patient and her parents. Kaplan-Meier curves were used to determine age of menarche and Cox regression analysis was employed to evaluate the effect of the type of school and BMI on the age of menarche. Results: The mean age at menarche was 12.7±0.04 years. Girls from public and private schools had their period at 12.5±0.1 and 13.05±0.05 years respectively. A negative correlation between z scores for BMIand age of menarche was observed (r-0.3: p =0.001). Girls whose menarche occurred before 11.5 years had higher z scores for BMI and a larger proportion were overweight, compared to girls who had menarche later. Cox regression analysis showed that after adjusment for BMI, age of menarche was similar in both types of schools. Conclusions: Age of menarche is ocurring three months earlier in girls from public schools, which is associated with higher z scores for BMI. Type of school, a marker of socio-economic status in Chile, affects timing of menarche due to differences in body mass index <![CDATA[<b><i>Predictive values for mortality in pulmonary embolism, of embolic load and right/left ventricular diameter ratio, measured by computed tomography</i></b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872007001100010&lng=en&nrm=iso&tlng=en Background: In pulmonary embolism, the computed tomography (CT) images can be used as a prognostic index measuring the embolic load, according to the location and size of thrombus and the right/left ventricular diameter ratio. Aim To assess the predictive value of embolic load and right/left ventricular diameter ratio for early and ¡ate mortality in acute pulmonary embolism (PTE). Material and methods: The pulmonary CT of 418 patients with suspected PTE were reviewed. Embolic load was assessed by three independent evaluators and the right/left ventricular diameter ratio was measured in those exams that were positive for PTE. A logistic regression analysis was done between these parameters and mortality. ReproducibUity was calculated using Bland andAltman analysis. Results: There was a high concordance between raters to calculate embolic load (r =0,95, p <0,001). Only the right/left ventricular diameter ratio and the presence were predictive of global mortality. The predictive value for embolic load was below the significance level No parameter was predictive of early mortality. Conclusions: The concordance between raters for the assessment of embolic load was high in this study. However no imaging parameter had a predictive value for early mortality. The right/left ventricular diameter ratio had a predictive value for global mortality at three months <![CDATA[<b><i>Val proate-associated hyperammonemic encephalopathy.</i></b><b><i> Report of one case</i></b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872007001100011&lng=en&nrm=iso&tlng=en Valproate can be associated to hyperammonemic encephalopathy, characterized by fluctuating sudden-onset alterations of sensorium, focal symptoms and an increase in the frequency of seizures. We report a 78 year-old female using valproate 1,000 mg/ day for 10 months for the treatment to tonic-clonic seizures. She was admitted on three occasions in the last fourth months for self limited clouding of sensorium. Laboratory, imaging and electroencephalografic studies were non-contributory Blood ammonia levels were 123 fig/dl (normal: 15-50 fig/dl). Due to the possibility of a hyperammonemic encephalopathy secondary to valproate, the drug was discontinued and she was treated with lactulose and intravenous L-carnitine, 1 g/day The patient showed a complete recovery within 48 hours. This drug-associated encephalopathy is a reversible but potentially fatal cause, probably underdiagnosed, that requires a high index of suspicion <![CDATA[<b><i>Molecular study of CYP21A2 gene for prenatal diagnosis of congenital adrenal hyperplasia</i></b>: <b><i>Report of a family</i></b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872007001100012&lng=en&nrm=iso&tlng=en Prenatal treatment of pregnancies at risk of congenital adrenal hyperplasia (CAH) may prevent ambiguous genitalia in female fetuses. We present the prenatal treatment performed in an extended family with two mutations. The proband, a boy with CAH-salt losing form, and his relatives were studied. The proband's paternal uncles/aunts were married to the maternal aunts/uncles, respectively. The relatives had normal basal and stimulated 170HProgesterone levels, which did not clarify their carrier status. The CYP21A2 gene was sequenced. The proband and the paternal relatives harbored a Q318X, R483W mutation in one alíele. The maternal relatives and the proband exhibited an R483 frameshift mutation. Early dexametasone treatment was given during two pregnancies and stopped when male gender was confirmed by early ultrasonography Both newborns were healthy and had normal 170HProgesterone levels. This family had three mutations which abolish the 21-hydroxilase activity. Two mutations were detected in codon 483 of CYP21A2 gene, exon 10, which have not been reported previously in Latin-America. The molecular study performed in this family allowed us to give an appropriate genetic counseling and prenatal treatment <![CDATA[<b><i>Hypokalemia</i></b><b><i>, hypovolemia and electrocardiographic changes due to furosemide abuse</i></b>: <b><i>Report of one case</i></b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872007001100013&lng=en&nrm=iso&tlng=en Hypokalemia (serum K+ < 3.5 mEq/1) is a potentially serious adverse effect of diuretic ingestión. We report a 27 year-old woman admitted with muscle weakness, a serum potassium of 2.0 mEq/1, metabolic alkalosis and EKG abnormalities simulating cardiac ischemia, that reverted with potassium chloride administration. She admitted high dose furosemide self-medication for edema. Glomerular filtration rate, tubular sodium reabsortion, potassium secretion, the renin-aldosterone system, total body water distribution and capillary permeability, were studied sequentially until 90 days after her admission. There was hyperactivity of the renin-aldosterone axis, reduction in extracellular and intracellular volumes, normal capillary permeability and high sodium tubular reabsorption, probably explained by a "rebound" salt retention associated with her decreased extracellular volume <![CDATA[<b><i>The association between maternal age and congenital malformations</i></b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872007001100014&lng=en&nrm=iso&tlng=en Background: There is an association between extreme maternal ages and the risk of congenital malformations. This is specially true for chromosomal abnormalities among women of advanced ages and disruptive malformation among teenage mothers. Aim: To determine the association between maternal ages and incidence of congenital malformations at the obstetric ward of a clinical hospital. To compare these figures with those of Chile. Material and methods: The hospital registries of the Latin American Collaborative Study of Congenital Malformations (ECLAMC) between 1996 and 2005, were consulted. This is a database of all marformations detected in newborns at the hospital. Results: An overall prevalence of malformations of8,4% was detected at the hospital. There is a significantly lower frequency of mothers aged less than 20 years than in the rest of Chile. Mothers aged between 20 and 29 years have the lower frequency of malformed children. Women aged ¡ess than 20 years and over 39 years of age, account for 56% of malformed children. Maternal ages and the rates of malformations, increased in a parallel fashion at a rate of 0.2 years and 2.2 malformed children per 1,000 born alive, per calendar year, respectively. Conclusions: The association between prevalence rates of congenital malformations and maternal age is U chaped with a higher proportion of malformed children among women aged ¡ess than 20 years or more than 39 years <![CDATA[<b><i>Masters of Internal Medicine, in Chile</i></b>: <b><i>Manuel García de los Ríos Álvarez MD.</i></b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872007001100015&lng=en&nrm=iso&tlng=en Background: There is an association between extreme maternal ages and the risk of congenital malformations. This is specially true for chromosomal abnormalities among women of advanced ages and disruptive malformation among teenage mothers. Aim: To determine the association between maternal ages and incidence of congenital malformations at the obstetric ward of a clinical hospital. To compare these figures with those of Chile. Material and methods: The hospital registries of the Latin American Collaborative Study of Congenital Malformations (ECLAMC) between 1996 and 2005, were consulted. This is a database of all marformations detected in newborns at the hospital. Results: An overall prevalence of malformations of8,4% was detected at the hospital. There is a significantly lower frequency of mothers aged less than 20 years than in the rest of Chile. Mothers aged between 20 and 29 years have the lower frequency of malformed children. Women aged ¡ess than 20 years and over 39 years of age, account for 56% of malformed children. Maternal ages and the rates of malformations, increased in a parallel fashion at a rate of 0.2 years and 2.2 malformed children per 1,000 born alive, per calendar year, respectively. Conclusions: The association between prevalence rates of congenital malformations and maternal age is U chaped with a higher proportion of malformed children among women aged ¡ess than 20 years or more than 39 years <![CDATA[<b><i>Strengths and weaknesses of the impact factor of scientific journals</i></b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872007001100016&lng=en&nrm=iso&tlng=en The impact factor is a bibliometric tool used to estimate the importance of scientific journals. It is calculated and published annually for journals indexed by the Institute for Scientific Information (ISI) and is a reflex of the average number of citations that each journal receives during a certain period of time. Since its creation it has been used as criteria in several decision-making processes such as buying journals subscriptions and submitting articles for publication. Operating under the hypothesis "the greater the impact factor, the greater the quality of a journal", it has been subject of numerous controversies, especially due to certain biases around its calculation. The present article describes the Impact Factor and analyses the most important aspects in relation to its calculation, strengths, ¡imitations and common errors on its application <![CDATA[<b><i>Self perception of clinical competences declared by recently graduated physicians of the University of </i></b>Chile]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872007001100017&lng=en&nrm=iso&tlng=en Background: The new curriculum of the University of Chile School of Medicine includes the evaluation not only of knowledge and skills, but also abilities and attitudes. Aim: To measure the self perceived level of basic clinical competences (BCC) declared by recently graduated physicians. Material and methods: A self evaluation survey was designed, based on the proposed objectives of the Faculty Curriculum Committee and on an instrument used in Spanish Universities. It contained 194 questions and the possible answers were: 1.1 know what it is and it has been explained to me; 2.1 have seen it done; 3.1 have done it before under supervision; 4. I would be capable to do it under any circumstance. It was applied confidentially to 50 of a total of 170 recently graduated physicians. Results: Perception of BCC for the diagnosis of most common diseases was felt as satisfactory. History taking and physical examination were also considered as achieved skills. Deficiences were found in practical aspects of nursing care, obstetric and gynecological abilities and reanimation procedures. Discussion: Answers may be biased considering that the survey was a self assessment procedure. However, results provide sound orientation to detect strengths and weaknesses of delivered education. Achievement of BCC is proportional to clinical practice opportunities as a student <![CDATA[<b><i>The ethical dilemma of water fluoridation</i></b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872007001100018&lng=en&nrm=iso&tlng=en Dental caries remains a worldwide public health problem because of its magnitude and impact on affected people's quality of life. Among preventive strategies, water fluoridation is one of the most important, but its value still remains uncertain after more than a half of Century of its use. The aim of this study is to analyse some of the ethical arguments for and against water fluoridation and to determine if empirical data allow to decide if there are correct policies from a bioethical perspective. Autonomy, compulsory medication (mass medication), precautionary principle, justice in health care and ethics of protection are discussed. It is concluded that fluoridation is beneficial and that there is no ethical reason to oppose it, based on a specific kind of ethics developed to analyse and clarify complex public health's issues <![CDATA[<b>Precautions for the Prevention of Plagiarism</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872007001100019&lng=en&nrm=iso&tlng=en Dental caries remains a worldwide public health problem because of its magnitude and impact on affected people's quality of life. Among preventive strategies, water fluoridation is one of the most important, but its value still remains uncertain after more than a half of Century of its use. The aim of this study is to analyse some of the ethical arguments for and against water fluoridation and to determine if empirical data allow to decide if there are correct policies from a bioethical perspective. Autonomy, compulsory medication (mass medication), precautionary principle, justice in health care and ethics of protection are discussed. It is concluded that fluoridation is beneficial and that there is no ethical reason to oppose it, based on a specific kind of ethics developed to analyse and clarify complex public health's issues