Scielo RSS <![CDATA[Revista médica de Chile]]> http://www.scielo.cl/rss.php?pid=0034-988720040008&lang=es vol. 132 num. 8 lang. es <![CDATA[SciELO Logo]]> http://www.scielo.cl/img/en/fbpelogp.gif http://www.scielo.cl <![CDATA[<B>Uso y abuso de antibióticos</B>: <B>Momento de su evaluación, más allá del ser humano</B>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0034-98872004000800001&lng=es&nrm=iso&tlng=es Antibiotics, once called the «wonder drugs» might be loosing their magic through development and dissemination of bacterial resistance. We are very responsible for that by way of inappropriate and excessive use of them. Although we have not created the problem we have promoted, accelerated and amplified it. So we used to think. Now we can share the blame: massive use in animal feed, seems to be contributing a great deal to the same effect, and they are not even used to treat infections, but to promote growth and weight gain. Dubious purpose, since same effects can be achieved with better and more hygienic feeding practices. Equal or larger amounts of antibiotics are thought to be used for this purpose than for human health. Resistance in animal flora and transmission to humans has been inevitable. In this issue, F Cabello reports this practice in Chilean aquaculture: greater amounts than in other countries and a wider range of antimicrobials are used here, some sharing chemical and spectrum properties with those for human use, some slowly biodegradable. This situation may have a great impact in bacterial resistance locally, along with other untoward consequences of exposing unnecessarily salmons, humans and the environment to bioactive products. The time to openly discuss the practice, probably quite unknown to the general public, and perhaps to some authorities, has come (Rev Méd Chile 2004, 132: 909-10) <![CDATA[<B>Práctica contemporánea de la angioplastia coronaria en Chile</B>: <B>Informe final del Registro Nacional de Angioplastia Coronaria (RENAC) 2001-2002</B>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0034-98872004000800002&lng=es&nrm=iso&tlng=es Background:Coronary angioplasty was introduced in Chile in 1982, but only after the introduction of stents it became commonplace. However, the results of this procedure at the national level remain largely unknown. Aim: To assess the results and characteristics of coronary angioplasty and develop a national registry in Chile (RENAC). Patients and Methods: All centers performing angioplasty were invited to contribute prospectively with the clinical, angiographic, procedural characteristics and results of all consecutive coronary angioplasty procedures attempted between June 2001 and October 2002. Results: In 10 centers, 1768 lesions were treated in 1484 procedures (22.98% in women). Mean age was 60.8±11.3 years old. Diabetes was found in 21.8%, hypertension in 60.2%, dyslipidemia in 52.0%, active smoking in 40.0%, renal failure in 6.2%. Myocardial infarction was recent in 28.4% and acute in 19.7%. Forty eight percent of patients had unstable angina and 15.5% had stable angina. Fifty three percent of patients had single vessel disease and 71%, normal left ventricular eyection fraction. One vessel was treated in 90.6% of patients and 81.7% of lesions were treated with stents, 17.9% only with baloon and in 0.4% with atherectomy. Angiographic success was obtained in 95.2%. Clinical success was obtained in 92.2%, and 95.1% in patients without acute myocardial infarction. Overall inhospital death was 2.2%. In patients without myocardial infarction, the figure was 1.1%. Conclusions: Coronary angioplasty in Chile is performed mostly for the treatment of acute coronary syndromes. Stents are the most frequently used devices. The high success, low mortality and complications observed are comparable to North American registries (Rev Méd Chile 2004; 132: 913-22) <![CDATA[<B>Obesidad materna y riesgo reproductivo</B>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0034-98872004000800003&lng=es&nrm=iso&tlng=es Background:The prevalence of obesity in school children and pregnant women, a known risk factor of the reproductive cycle, has increased significantly over the last few years. Aim: To analyze the association between maternal obesity and the outcome of pregnancy and newborn health. To quantify the attributable population risk of obesity in relation to negative events of pregnancy. Material and methods: A prospective study in 883 pregnant women of 6 public health centers in Santiago. Weight, height, arm circumference, skinfold thicknesses, body mass index (BMI) and fat mass were determined in each trimester. Maternal socio demographic history, smoking habits, incidence of diseases during pregnancy, labor and newborn characteristics were analyzed. Logistic regressions of multiple factors were used to determine nutritional and non-nutritional variables associated to negative events, to determine the population attributable risk of each variable that the model retained. Results: Controlling the effect of other variables, a BMI ž30 or initial body fat mass ž35% determined a greater risk for assisted labor with an odds ratio (OR) of 1.9 (95% confidence interval (CI) 1.3-2.9), gestational diabetes with an OR of 6.4 (95% CI 2.1-19.6), hypertension with an OR of 7.8 (95% CI 3.0-20.4), late fetal mortality with an OR of 3.4 (95% CI 1.2-10.0), p <0.001. The risk was mostly associated with the initial maternal nutritional status and in a lesser degree, with the weight gained during pregnancy. Conclusions: Maternal obesity is an important risk factor during pregnancy. The prenatal control obesity could reduce approximately 10% of the cesarean sections and late fetal deaths and half of the hypertension and gestational diabetes cases (Rev Méd Chile 2004; 132: 923-30) <![CDATA[<B>Incidencia de diabetes gestacional y su relación con obesidad en embarazadas chilenas</B>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0034-98872004000800004&lng=es&nrm=iso&tlng=es Background: Gestational diabetes (GDM) is associated to a worse outcome of pregnancy. This justifies efforts for finding possible causes of GDM that would allow implementing preventive interventions. Aim: To study incidence of GDM and its relation with obesity and other traditional risk factors. Material and methods: A retrospective study was performed in 234 women who had delivered a singleton during the last 12 months, attended in an outpatient clinic in Santiago, Chile. Familiar and personal history, body mass index (BMI), obstetrical-related pathology and data about the labor and the newborn were analyzed. Results: GDM was diagnosed in 11.2% of the women. BMI before pregnancy was 26.6 ± 4.4 kg/m2 (mean ± SD) and it was 25 or over in 37.8% of women. Women who developed GDM had significantly higher BMI in the pre-pregnancy stage and in the second and third trimester of pregnancy (p <0.001). The average age was greater in the GDM group (31±0.2 yr versus 26±0.41 yr). Incidence of GDM was 14.4% among women 25 years old or older and increased to 21.4% when they had, in addition, a BMI of 25 or over. Age, BMI, and family history of diabetes were all independently correlated with the development of GDM. Elective caesarean sections were more common in GDM than in non-GDM women (p = <0.01) and complications were present in 3/23 of newborns of women with GDM and 2/199 among women without GDM (p <0.01) Conclusions: GDM and obesity are highly prevalent in Chilean pregnant women. BMI, first degree relative with DM and age are independent risk factors for the development of GDM (Rev Méd Chile 2004; 132: 931-8) <![CDATA[<B>Alteraciones motoras gastrointestinales en la enfermedad de Chagas </B>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0034-98872004000800005&lng=es&nrm=iso&tlng=es Serum antibodies against Trypanosoma Cruzi have been observed in 19% of the Chilean population. Marked differences in organ involvement have been reported in patients with Chagas disease. Chagas disease is rarely an aetiological factor for achalasia in Chile, which is different from reports in other countries of South America. In contrast, a high incidence of megacolon among these patients have been reported. Aim: To study the incidence of gastric and small intestinal motor disorders among these patients and their relationship to esophageal and colon motility disorders. Patients and Methods: We studied 18 patients, 12 women (mean age 45 years); with positive antibodies against T Cruzi. Seven had radiological evidence of megacolon and no one had radiological or manometric evidence for achalasia. Non specific motor esophageal abnormalities were found in 11 patients. Nine had an abnormal electrocardiogram, suggesting a myocardial disease. A questionnaire for gastrointestinal symptoms, an electrogastrography and a small intestinal motility study, were performed in each patient. Results: All patients had evidences of abnormalities in at least one segment of the digestive tract. Twelve patients had an abnormal electrogastrographic study, with bradygastria as the most common finding. Nine had an abnormal small intestinal manometry with a myophatic pattern evidenced by a decreased amplitude of contractions (18.5±3 mmHg). Also an increased number of clustered contractions was observed. Conclusions: Gastric dysrhythmias and small intestinal motor abnormalities are frequently associated to non specific esophageal motor disorders and megacolon in patients with Chagas disease (Rev Méd Chile 2004; 132: 939-4) <![CDATA[<B>Síndrome de edema de la médula ósea de cadera</B>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0034-98872004000800006&lng=es&nrm=iso&tlng=es Background: Bone marrow edema syndrome (BMES) is a rare clinical condition. Its etiology is unknown and it can be seen in different locations. In the case of the hip, avascular necrosis is the main differential diagnosis. Aim: To present our experience of BMES of the hip and a review of the literature. Patients and methods: Retrospective analysis of clinical records of patients with hip pain that met clinical, radiological, and magnetic resonance imaging criteria for BMES. Clinical outcome and clinical and radiological follow up are presented. Results: Two men and two women (one of them pregnant) aged 42, 48, 36 and 26 years old, fulfilled criteria. Treatment included limited weight bearing, non steroidal antiinflammatory drugs, intranasal calcitonin and physical therapy. Complete remission of symptoms was observed within five to seven months. At an average follow up of 36 months, all patients presented complete function of the hip, returning to their previous activity levels, with no new episodes of BMES. Conclusions: It is important to be aware of this condition as part of the differential diagnosis of hip pain to avoid aggressive and unnecessary diagnostic and therapeutic procedures (Rev Méd Chile 2004; 132: 947-54 <![CDATA[<B>Mutación del gen K-ras en el cáncer de la vesícula biliar</B>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0034-98872004000800007&lng=es&nrm=iso&tlng=es Background: Different K-ras mutation frequencies in gallbladder cancer have been reported. Aim: To study the frequency of K-ras gene mutations in advanced gallbladder carcinoma not associated to anomalous junction of pancreatic-biliary duct (AJPBD). Material and methods: 33 formalin fixed paraffin embedded samples of gallbladder carcinoma (30 women, age range 32-86 years) were selected. Pancreatic cancer tissue with K-ras mutations was used as control. DNA was extracted from the histological section by mean of microdissection and K-ras mutations in codon 12 were detected by polymerase chain reaction and restriction fragment length polymorphism (RFLP), using previously reported technique. Results: Most cases were poorly differentiated adenocarcinomas. K-ras mutation was detected in 10 cases (30%) samples. No differences in K-ras mutation frequency between subserous and serous tumors were detected and no relation between histological features and the mutation was observed. Conclusions: K-ras mutation in codon 12 is present in 30% in our advanced gallbladder carcinomas. The study of K-ras mutation in preneoplastic lesions and early carcinomas will be important to determine the role of this gene in the gallbladder carcinogenesis in Chile (Rev Méd Chile 2004; 132: 955-60) <![CDATA[<B>Interacciones genéticas y genético-ambientales como efecto modificador del riesgo de cáncer de próstata</B>: <B>un diseño <I>«case-only»</I> </B>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0034-98872004000800008&lng=es&nrm=iso&tlng=es Background: The role of susceptibility low penetrance genes and environmental factors in the etiology of prostate cancer (PCa) is unclear, but may involve in some cases multiple alleles at multiple loci. Aim: To evaluate the association of gene-gene and gene-environment interactions with PCa. Patients and methods: One hundred three subjects with biopsy proven PCa were studied, using a case-only design. All were interrogated about smoking habits. Polymorphisms for Glutathione-S-transferase (GST) and Cytochrome P4501A1 (CYP1A1), were measured in DNA extracted from peripheral Iymphocytes, using a restriction fragment length polymorphism analysis. Results: Our findings suggest that gene-gene interactions between GSTT1 and CYP1A1 high risk genotypes were positive modifiers and had a high predictive value for the presence of PCa, compared with non-susceptibility genotypes. The interaction between susceptibility genotypes and smoking did not modify the risk for PCa. Conclusions: Gene-gene interactions may play a role modulating the susceptibility to PCa in a proportion of affected individuals (Rev Méd Chile 2004; 132: 961-66) <![CDATA[<B>Concordancia diagnóstica del puntaje de Gleason en biopsia por punción y prostatectomía radical y sus consecuencias clínicas</B>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0034-98872004000800009&lng=es&nrm=iso&tlng=es Background: The Gleason histological score is an independent prognostic factor in prostate cancer that helps in therapeutic decisions. Aim: To analyze the concordance between the Gleason score of needle prostatic biopsy and the score from the study of the surgical piece obtained during radical prostatectomy. Material and methods: Retrospective analysis of 212 cases of prostate cancer, diagnosed between February 1993 and March 2003. All had the Gleason histological scores from needle prostatic biopsies and in the surgical piece obtained during radical prostatectomy. All pathological studies were done by the same observer. Results: There was an exact concordance of Gleason scores between needle biopsy and the surgical piece in 49% of cases and a concordance of ± 1 unit in 89%. The concordance improved in the second half of the study period. No cases with a Gleason score of less than 5 were detected since 1999 in the surgical piece. Conclusions: The concordance of Gleason score of needle prostatic biopsies and surgical pieces is good. This concordance increases with the experience of the pathologist (Rev Méd Chile 2004; 132: 971-8) <![CDATA[<B>Tiempo de exposición al gluten y marcadores de riesgo de diabetes mellitus insulino dependiente en pacientes celíacos</B>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0034-98872004000800010&lng=es&nrm=iso&tlng=es Background: Celiac patients are at high risk of developing insulin-dependent diabetes mellitus, a condition that has a long pre-diabetic period. During this lapse, anti-islet cell antibodies serve as markers for future disease. This may be related with the duration of the exposure to gluten. Aim: To test the hypothesis that long term adherence to a gluten free diet decreases the frequency of risk markers for insulin dependent diabetes mellitus during adolescence and early adulthood. Patients and methods: 158 celiac patients were classified as: G1, (n=30 patients) studied at the time of diagnosis; G2 (n=97 patients) exposed to gluten as a result of non compliance with the gluten free diet and, G3 (n=31 patients) who had maintained a long term, strict gluten free diet. Isotype IgG anti-islet cell antibodies were detected by indirect immunofluorescence using monkey pancreas; results were reported in Juvenile Diabetes Foundation (JDF) units. Results: Celiac patients exposed to a gluten containing diet had a significantly higher prevalence of anti-islet cell antibodies than those who had been exposed only briefly (p <0.017). In addition, a significantly higher prevalence of anti-islet cell antibodies was observed in those patients whose exposure to gluten was longer than 5 years than in those whose exposure was shorter (p <0.02). Conclusions: Celiac patients long exposed to gluten have a significantly higher prevalence of anti-islet cell antibodies than those exposed for a short period. This fact supports the hypothesis that the development of these antibodies is associated with the length of the exposure to gluten (Rev Méd Chile 2004; 132: 979-84) <![CDATA[<B>Cáncer colorrectal de presentación atípica</B>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0034-98872004000800011&lng=es&nrm=iso&tlng=es We report a 67 years old male with a history of pulmonary tuberculosis at the age of 15, that consults for malaise, weight loss and productive cough. Chest X ray examination showed a left pleural effusion. A pleural tap obtained a sterile exudate. A thorax CAT scan showed a proliferating mass in the splenic angle of the colon, with left lung and diaphragmatic invasion. Endoscopic biopsies confirmed the diagnosis of adenocarcinoma. The patient underwent a subtotal colectomy with partial excision of diaphragm and left lung. The pathological report showed a mucosecretory adenocarcinoma, infiltrating the pericolonic adipose tissue without adjacent organ infiltration and a chronic inflammatory process involving colonic serosa, diaphragm pleura, and lung. Adjuvant chemotherapy was indicated and the patient is asymptomatic and without evidences of tumor recurrence after a 24 months follow up (Rev Méd Chile 2004; 132: 985-88) <![CDATA[<B>Aplasia medular tratada exitosamente con ciclosporina en un paciente en hemodiálisis crónica</B>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0034-98872004000800012&lng=es&nrm=iso&tlng=es A 28 years old male on chronic hemodialysis for 40 months due to a IgA crescentic glomerulonephritis developed pancytopenia (hematocrit 16%, white blood cell count 3.800 mm³ and platelets 11.000 mm³. The bone marrow aspirate showed erythropoietic hyperplasia. Hemolytic anemia, folate or vitamin B12 deficiency and paroxysmal nocturnal hemoglobinuria were ruled out. Steroids were given with a transient elevation of red cells and platelets, which lasted only for some weeks. Afterwards, intravenous immunoglobulin was given without benefit. Two months after, a bone marrow biopsy and a bone marrow magnetic resonance imaging showed severe aplasia. Cyclosporine was started with a rapid increase in blood cells count. Eight months later, he received a renal transplant from a cadaveric donor. Immunosupression was achieved with cyclosporine, prednisone and mycofenolate mofetil. The patient required hemodialysis for the first three weeks and a mild acute cellular rejection was treated with methylprednisolone. At discharge, 6 weeks later, serum creatinine was 2.4 mg/dl and creatinine clearance 37.6 ml/min. During the first months after transplant, platelet count and hemoglobin decreased and a bone marrow biopsy showed only mild hypoplasia. Four months after renal transplant the hematocrit was 43%, white blood cell count 6.600 mm³ and platelets, 150.000 mm³ and did not change during the first year of follow up (Rev Méd Chile 2004; 132: 989-94 <![CDATA[<B>Hiperinsulinismo neonatal persistente</B>: <B>Análisis del diagnóstico diferencial a propósito de dos casos clínicos</B>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0034-98872004000800013&lng=es&nrm=iso&tlng=es Persistent neonatal hyperinsulinism is the most common cause of refractory hypoglycemia during the first year of life. Inadequate insulin secretion is associated to mutations of four different genes, that can be diagnosed to orient patient management. We report two patients: a female newborn that presented a hypoglycemia of 16 mg/dl two hours after birth, was subjected to a subtotal pancreatectomy that did not correct hypoglycemia, requiring a total pancreatectomy. Pathological study of the pancreas showed a focal adenomatous hyperplasia. At the present time, she is three years of age and maintains euglycemia with fractionated feeding. A male newborn that had seizures at 28 hours of life and a hypoglycemia of 15 mg/dl was detected. He was also subjected to a subtotal pancreatectomy, that did not correct hypoglycemia and had to be extended to a total pancreatectomy. At the present time, he is 3 years and 11 months of age and has a normal psychomotor development (Rev Méd Chile 2004; 132: 995-1000) <![CDATA[<B>Antibióticos y acuicultura en Chile</B>: <B>consecuencias para la salud humana y animal </B>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0034-98872004000800014&lng=es&nrm=iso&tlng=es Industrial antibiotic usage in agribusinesses and aquaculture is the force that drives the evolution of antibiotic resistant bacteria that produce human and animal disease in many countries. Several studies have demonstrated that most of the industrial use of antibiotics is unnecessary, and that modernization and hygienic changes can reduce this use of antibiotics without negative economic impact. In Chile, industrial aquaculture of salmon has expanded rapidly in the last 20 years becoming a major export business. The exponential growth of this industry has been accompanied by an unrestricted heavy usage of antibiotics in the aquatic environments of lakes, rivers and the ocean, and its impact is being felt in the emergence of antibiotic-resistant bacteria around aquaculture sites and a decrease in the plancktonic diversity in the same areas. The passage of antibiotic resistance genes from aquatic bacteria to human and animal pathogens has been demonstrated, indicating that industrial use of antibiotics in aquaculture affects negatively the antibiotic therapy of human and animal bacterial infections. The Chilean situation triggers important concerns because it includes the use of fluoroquinolones in aquaculture, that are not biodegradable and are able to remain in the environment for years as well as being still effective in treating human infections. The use of large volumes of a wide spectrum of antibiotics in an aquatic environment heavily contaminated with human and animal pathogens also amplifies the opportunities for gene transfer among bacteria, facilitating the emergence of antibiotic resistance and more pathogenic bacterial recombinants. The detection of residual antibiotics in salmons marketed for human consumption that can modify the normal flora of the population also suggests the need for controls on this antibiotic usage and on the presence of residual antibiotics in aquaculture food products. This important problem of public health demands an active dialogue between government officials responsible for protecting public health, aquaculture industry representatives, politicians, consumers and professionals dealing with these matters (Rev Méd Chile 2004; 132: 1001-6) <![CDATA[<B>Por qué vale la pena randomizar en un estudio de terapia?</B>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0034-98872004000800015&lng=es&nrm=iso&tlng=es Industrial antibiotic usage in agribusinesses and aquaculture is the force that drives the evolution of antibiotic resistant bacteria that produce human and animal disease in many countries. Several studies have demonstrated that most of the industrial use of antibiotics is unnecessary, and that modernization and hygienic changes can reduce this use of antibiotics without negative economic impact. In Chile, industrial aquaculture of salmon has expanded rapidly in the last 20 years becoming a major export business. The exponential growth of this industry has been accompanied by an unrestricted heavy usage of antibiotics in the aquatic environments of lakes, rivers and the ocean, and its impact is being felt in the emergence of antibiotic-resistant bacteria around aquaculture sites and a decrease in the plancktonic diversity in the same areas. The passage of antibiotic resistance genes from aquatic bacteria to human and animal pathogens has been demonstrated, indicating that industrial use of antibiotics in aquaculture affects negatively the antibiotic therapy of human and animal bacterial infections. The Chilean situation triggers important concerns because it includes the use of fluoroquinolones in aquaculture, that are not biodegradable and are able to remain in the environment for years as well as being still effective in treating human infections. The use of large volumes of a wide spectrum of antibiotics in an aquatic environment heavily contaminated with human and animal pathogens also amplifies the opportunities for gene transfer among bacteria, facilitating the emergence of antibiotic resistance and more pathogenic bacterial recombinants. The detection of residual antibiotics in salmons marketed for human consumption that can modify the normal flora of the population also suggests the need for controls on this antibiotic usage and on the presence of residual antibiotics in aquaculture food products. This important problem of public health demands an active dialogue between government officials responsible for protecting public health, aquaculture industry representatives, politicians, consumers and professionals dealing with these matters (Rev Méd Chile 2004; 132: 1001-6) <![CDATA[<B>Análisis crítico de un artículo </B>: <B>Acetilcisteína para prevenir falla renal por medio de contraste Birck R, Krzossok S, Markowetz F, Schnulle P, van der Woude FJ, Braun C. Acetylcysteine for prevention of contrast nephropathy: meta-analysis. Lancet 2003; 362 (9384): 598-603</B>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0034-98872004000800016&lng=es&nrm=iso&tlng=es Background: Contrast nephropathy is associated with increased in hospital morbidity and mortality and leads to extension of hospital stay in patients with chronic renal insufficiency. Acetylcysteine seems to be a safe and inexpensive way to reduce contrast nephropathy. We aimed to assess the efficacy of acetylcysteine to prevent contrast nephropathy after administration of radiocontrast media in patients with chronic renal insufficiency. Methods: We did a meta-analysis of randomized controlled trials comparing acetylcysteine and hydration with hydration alone for preventing contrast nephropathy in patients with chronic renal insufficiency. The trials were identified through a combined search of the BIOSIS+/RRM, MEDLINE, Web of Science, Current Contents Medizin, and The Cochrane Library Databases. We used incidence of contrast nephropathy 48 h after administration of radiocontrast media as an outcome measure. Findings: Seven trials including 805 patients were eligible according to our inclusion criteria and were analyzed. Overall incidence of contrast nephropathy varied between 8% and 28%. Since significant heterogeneity was indicated by the Q statistics (p=0.016) we used a random effects model to combine the data. Compared with periprocedural hydration alone, administration of acetylcysteine and hydration significantly reduced the relative risk of contrast nephropathy by 56% (0.435 [95% CI 0.215-0.879], p=0.02) in patients with chronic renal insufficiency. Meta-regression revealed no significant relation between the relative risk of contrast nephropathy and the volume of radiocontrast media administered or the degree of chronic renal insufficiency before the procedure. Interpretation: Compared with periprocedural hydration alone, acetylcysteine with hydration significantly reduces the risk of contrast nephropathy in patients with chronic renal insufficiency. The relative risk of contrast nephropathy was not related to the amount of radiocontrast media given or to the degree of chronic renal insufficiency before the procedure <![CDATA[<B>Blastocistosis</B>: <B>enteroparasitosis más frecuente en Chile</B>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0034-98872004000800017&lng=es&nrm=iso&tlng=es Background: Contrast nephropathy is associated with increased in hospital morbidity and mortality and leads to extension of hospital stay in patients with chronic renal insufficiency. Acetylcysteine seems to be a safe and inexpensive way to reduce contrast nephropathy. We aimed to assess the efficacy of acetylcysteine to prevent contrast nephropathy after administration of radiocontrast media in patients with chronic renal insufficiency. Methods: We did a meta-analysis of randomized controlled trials comparing acetylcysteine and hydration with hydration alone for preventing contrast nephropathy in patients with chronic renal insufficiency. The trials were identified through a combined search of the BIOSIS+/RRM, MEDLINE, Web of Science, Current Contents Medizin, and The Cochrane Library Databases. We used incidence of contrast nephropathy 48 h after administration of radiocontrast media as an outcome measure. Findings: Seven trials including 805 patients were eligible according to our inclusion criteria and were analyzed. Overall incidence of contrast nephropathy varied between 8% and 28%. Since significant heterogeneity was indicated by the Q statistics (p=0.016) we used a random effects model to combine the data. Compared with periprocedural hydration alone, administration of acetylcysteine and hydration significantly reduced the relative risk of contrast nephropathy by 56% (0.435 [95% CI 0.215-0.879], p=0.02) in patients with chronic renal insufficiency. Meta-regression revealed no significant relation between the relative risk of contrast nephropathy and the volume of radiocontrast media administered or the degree of chronic renal insufficiency before the procedure. Interpretation: Compared with periprocedural hydration alone, acetylcysteine with hydration significantly reduces the risk of contrast nephropathy in patients with chronic renal insufficiency. The relative risk of contrast nephropathy was not related to the amount of radiocontrast media given or to the degree of chronic renal insufficiency before the procedure <![CDATA[<b>Crónica</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0034-98872004000800018&lng=es&nrm=iso&tlng=es Background: Contrast nephropathy is associated with increased in hospital morbidity and mortality and leads to extension of hospital stay in patients with chronic renal insufficiency. Acetylcysteine seems to be a safe and inexpensive way to reduce contrast nephropathy. We aimed to assess the efficacy of acetylcysteine to prevent contrast nephropathy after administration of radiocontrast media in patients with chronic renal insufficiency. Methods: We did a meta-analysis of randomized controlled trials comparing acetylcysteine and hydration with hydration alone for preventing contrast nephropathy in patients with chronic renal insufficiency. The trials were identified through a combined search of the BIOSIS+/RRM, MEDLINE, Web of Science, Current Contents Medizin, and The Cochrane Library Databases. We used incidence of contrast nephropathy 48 h after administration of radiocontrast media as an outcome measure. Findings: Seven trials including 805 patients were eligible according to our inclusion criteria and were analyzed. Overall incidence of contrast nephropathy varied between 8% and 28%. Since significant heterogeneity was indicated by the Q statistics (p=0.016) we used a random effects model to combine the data. Compared with periprocedural hydration alone, administration of acetylcysteine and hydration significantly reduced the relative risk of contrast nephropathy by 56% (0.435 [95% CI 0.215-0.879], p=0.02) in patients with chronic renal insufficiency. Meta-regression revealed no significant relation between the relative risk of contrast nephropathy and the volume of radiocontrast media administered or the degree of chronic renal insufficiency before the procedure. Interpretation: Compared with periprocedural hydration alone, acetylcysteine with hydration significantly reduces the risk of contrast nephropathy in patients with chronic renal insufficiency. The relative risk of contrast nephropathy was not related to the amount of radiocontrast media given or to the degree of chronic renal insufficiency before the procedure