Scielo RSS <![CDATA[Revista médica de Chile]]> vol. 129 num. 10 lang. es <![CDATA[SciELO Logo]]> <![CDATA[Actividad rítmica espontánea en vasos de placenta humana: ¿Un marcapaso fisiológico en los vasos sanguíneos?]]> Background: Placental vessels are not innervated. Therefore the vasomotor activity and vascular tone is not regulated by the nervous system. Aim: To assess the existence of pacemaker mechanisms related to rhythmic motor activity of blood vessels. Material and methods: Isometric contractions of rings from umbilical and chorionic vessels of term human placentas were monitored. Results: Recordings of the circular layer of chorionic and umbilical vessels revealed rhythmic spontaneous contractions with a frequency of 1,4±0,05 cycles/min, the duration of each cycle was 42,8±0,24 s (n=12). The amplitude of contractions was larger in veins than in arteries, predominating in umbilical vein biopsies, proximal to the fetus. Both the frequency and the amplitude of contractions were relatively constant during the first 30 min. However, after an hour, the frequency declined while the amplitude increased. The absence of the endothelium neither modified the frequency nor the amplitude of the rhythmic activity. Blockage of voltage dependent sodium channels or calcium channels did not alter the frequency of spontaneous contractions, although their magnitude was reduced. Glibenclamide, an ATP-dependent K+ channel blocker or the blockade of gap junctions ablated the frequency and amplitude of spontaneous contractions. Conclusions: We propose that rhythmic contractions are triggered by pacemaker cells located in the circular layer of the smooth muscle of blood vessels and spread via gap junctions; they likely contribute to the control of blood flow (Rev Méd Chile 2001; 129: 1105-12) <![CDATA[Carcinoma incipiente de la vesícula biliar: Estudio clínico-patológico y pronóstico de 196 casos]]> Background: There is little information about the behavior of early gallbladder carcinoma. Aim: To report the clinical and pathological features of 196 patients with early gallbladder carcinoma. Material and methods: All patients with gallbladder cancer diagnosed between 1988 and 1997 were reviewed. In 703 of 829 patients, there was information about clinical features and follow up, and were included in this study. All gallbladders were subjected to a complete mapping. When neoplastic cells involved only the mucosa or muscular layer, the tumors were considered as early. Results: One hundred ninety six patients had an early carcinoma (161 women, aged 57.5 years and 35 male, aged 63.4 years). One hundred twenty eight tumors were located in the mucosa and 68 in the muscular layer. Patients with tumors involving the mucosa were younger than those with tumors involving the muscular layer. All tumors were adenocarcinomas, 66% were well differentiated and 32% moderately differentiated. Tumors were not visible macroscopically in 132 cases. Five and 10 years survival was 92%. Subjects of less than 40 years old had a 100% survival at 5 years. A hepatic and lymph node resection was done in 12 patients with tumors infiltrating the muscular layer but in only one, the tumor infiltrated the liver. No difference in survival was observed when a simple cholecystectomy or radical surgery was done. Conclusions: Nearly 25% of gallbladder carcinomas can be classified as early and its diagnosis requires a directed study <![CDATA[Efecto de la vitamina K oral e intramuscular sobre los factores II, VII, IX, X y PIVKA II en el recién nacidohasta los 60 días de edad: Relación con la alimentación]]> Background: Neonates on exclusive breast feeding that do not receive vitamin K at birth are at higher risk hemorrhagic disease of the newborn. Aim: To compare the effect of oral or intramuscular administration of vitamin K1 (VK1), on clotting factors II, VII, IX, X and PIVKA II, in children until the 60 days of age with exclusive breast feeding or mixed feeding. Patients and methods: Forty healthy full term infants, distributed in two groups, A: 20 with mixed feeding (formula-feeding and breast-feeding) and B: 20 with exclusive breast feeding, were studied. Nine infants of each group received 1 mg of VK1 intramuscularly and eleven 2 mg VK orally. 5 ml of cord blood was collected initially from each infant. Venous blood samples were taken on 15, 30 and 60 days of age. Results: All factors increased in a progressive form reaching levels over 50% at 60 days of age, in both groups. PIVKA II decreased significantly during the study period (p <0.01). Factor II increased more in children with mixed feeding that received intramuscular vitamin K, than in the rest of study groups. No other differences between groups were observed. No infant had an abnormal bleeding during the study period. Conclusions: Oral administration of vitamin K is as effective as the intramuscular route in the prevention of the hemorrhagic disease of the newborn (Rev Méd Chile 2001; 129: 1121-9) <![CDATA[Reoperaciones coronarias: análisis retrospectivo de 16 años de experiencia]]> Background: Coronary artery bypass grafting (CABG) reoperation is being performed with increasing frequency. Aim: To assess the early and long term results of coronary reoperations in our institution and to identify prognostic factors. Patients and methods: 214 patients subjected to coronary reoperations between 1983 and 1999 were retrospectively studied. Results: Mean age was 64.2 years (range 42-79 years), 202 (94.4%) were male and 12 (5.6%) female. The mean interval between the operations was 125.7 months (range 6-252 months). 10 (4,6%) were emergency surgeries. Overall operative mortality was 5.6% (11 deaths) and in 5 patients (3.4%) a perioperative myocardial infarction was noted. Univariate analysis identified moderate or severe left ventricular failure (p=0.048) as predictor of increased operative mortality, meanwhile age over 75 years (p=0.02) and moderate or severe left ventricular failure (p=0.01) were identified as predictors of increased in hospital mortality in the multivariate analysis. Follow up of in hospital survivors (mean interval 65 months, range 4 to 190 months) documented a 5 years survival rate of 82.9%, a 10 years survival rate of 73.1% and a 15 years survival rate of 53.4%. Moderate or severe left ventricular failure (p <0.0001) and emergency surgeries (p=0.007) were identified as factors influencing the late survival in the stepwise logistical regression analysis. Multivariate analysis identified left ventricular failure (p=0.01) and peripheral vascular disease (p=0.01) as predictors of decreased late survival. Conclusions: Coronary reoperation has a low mortality in patients with a normal ventricular function and also has an excellent overall and disease free survival in the first 10 years of follow up. Left ventricular function is an independent risk factor increasing in hospital and late mortality (Rev Méd Chile 2001; 129: 1131-41) <![CDATA[Resultados preliminares de la esofagomiotomía por video laparoscopia en pacientes con acalasia esofágica: <I>Preliminary results in 19 patients</I>]]> Background: Laparoscopic esophagomyotomy is becoming a good alternative to pneumatic dilatation, injection of botulinic toxin or classical surgery in the treatment of achalasia. Aim: To report the results of laparoscopic esophagomyotomy in patients with achalasia. Patients and methods: Nineteen patients with achalasia, nine women, aged 9 to 66 years old, operated between 1996 and 2001 are reported. Results: There was no surgical mortality. One patient had a subphrenic abscess due to an unnoticed tear of the esophageal mucosa. During surgery, esophageal mucosa was perforated in 4 patients, that was sutured in three. One patient with an extensive tear of the mucosa required conversion to classical surgery. Patients were followed for 2 to 48 months. Radiological controls showed a significant increase in the diameter of gastroesophageal junction and a diameter reduction of the mid third esophageal segment. Lower esophageal pressure was significantly reduced. All patients experienced a weight increase and reduction of dysphagia. Conclusions: Laparoscopic esophagomyotomy is a safe an effective therapeutic alternative for achalasia (Rev Méd Chile 2001; 129: 1142-46) <![CDATA[<I>Helicobacter pylori</I>: análisis de <I>cagA</I> y genotipificación de <I>vacA</I> en Chile. Detección de una cepa s2/m1]]> Background: The genes cagA and vacA encode H pylori virulence factors. Aim: To genotype these genes in H pylori strains isolated from patients with upper gastrointestinal symptoms. Material and methods: We studied 50 patients who underwent an upper gastrointestinal endoscopy, with positive culture for H pylori. Detection of cagA and vacA gerotyping was done using polymerase chain reactions. Results: The gene cagA was detected in 19 samples (38%). Signal sequences s1 and s2 of vacA gene were detected in 16 samples each (32%). There was simultaneous amplification of s1 and s2 in 6 samples and they were not detected in 9 samples. The middle region of vacA was m1 in 9 samples, m2 in 29 samples and there was simultaneous amplification of m1 and m2 in 12 samples. In 16 samples (32%), more than one type of signal sequence or medial region was detected. Of those patients in whom vacA was the only genotype detected, 15 were s2/m2, 7 were s1/m1, 4 were s1/m2 and 1 was s2/m1. Conclusions: In these patients, the infection with cagA- H pylori strains, predominates, the prevalence of infection with s1 or s2 strains is similar and the predominant medial region is m2 (Rev Méd Chile 2001; 129: 1147-53 <![CDATA[Características biológicas, familiares y metabólicas de la obesidad infantil y juvenil]]> Obesity is the most prevalent nutritional disease in people of less than 20 years old. Aim: To report biological, familial and metabolic characteristics in obese children. Patients and methods: A retrospective review of 187 children seen at obesity clinics and that had a complete metabolic study. Results: Ninety five prepuberal and 92 puberal children, aged 8.7±2.2 and 12.6±2.2 years old respectively, were studied. Body mass index was over 4 standard deviations in 48.4% of prepuberal children and in 39.1% of puberal children. Paternal obesity was twice more prevalent (30.2%) than in the general population. The daily caloric intake and basal metabolic rate (BMR) were within the normal range; nevertheless there was a positive caloric balance due to minimal physical activity. The mean daily fat intake was normal (26.4±8.5 and 25.3±9.1% of total calories in prepuberal and puberal children respectively). The daily fiber intake was under 70% of recommendation. The total cholesterol was over 200 mg/dl in 26.6 and 23.9% of prepuberal and puberal children. LDL cholesterol was over 130 mg/dl in 27.3 and 26.6% and triacylglycerol was over 150 mg/dl in 16.9 and 25% of prepuberal and puberal children respectively. Basal serum insulin was over 20 uIU/ml in 27.7 and 42.2% of prepuberal and puberal children, respectively. Post glucose serum insulin was over 60 uIU/ml in 40 and 63% of prepuberal and puberal children, respectively. Conclusions: Infantile and juvenile obesity is a chronic disease with a high incidence of metabolic alterations (Rev Méd Chile 2001; 129: 1155-62) <![CDATA[Malformaciones del sistema nervioso central en el Hospital Clínico de la Universidad de Chile y maternidades chilenas participantes en el Estudio Colaborativo Latinoamericano de Malformaciones Congénitas (ECLAMC)]]> Background: In Chile, the rates of central nervous system congenital malformations at birth remain high, when compared with the rest of the world. Aim: To report the rates of central nervous system congenital malformations in Chilean hospitals. Material and methods: Using the ECLAMC protocol, every malformed newborn or stillbirth, weighing more than 500 g at birth is registered using a standard protocol, and the next non malformed child of the same sex born in the same hospital is assigned as control. Results: The rates of central nervous system congenital malformations are higher at the University of Chile Clinical Hospital than in the rest of Chilean hospitals or Latin American Hospitals. There are significantly higher rates of anencephalia in Concepcion and spina bifida in Valdivia, Rancagua and Concepcion. In the University of Chile Clinical Hospital, global annual rates have a negative slope of -0.0259 per 1000 born alive, with a correlation coefficient of -0.125 (p <0.05). The slope is positive among children born alive, with an annual rate increase of 0.071. Among stillbirths, the slope is -0.47 per 1000 born alive. Sixty two percent of malformed children were female. Among children with neural tube defects, 30% had a malformed relative and, of these, 66% had the same malformation. Conclusions: Family clustering of neural tube defects, supports the influence of a genetic factor influencing their appearance (Rev Méd Chile 2001; 129: 1163-70) <![CDATA[Efecto de la prueba de la caminata de seis minutos sobre la hiperinflación pulmonar en pacientes con enfermedad pulmonar obstructiva crónica avanzada]]> Background: Exercise tolerance in patients with COPD is highly variable and poorly related to airways obstruction assessed by FEV1. These patients develop dynamic hyperinflation (DH) during an incremental exercise test which can be evaluated through a reduction in inspiratory capacity (IC). Aim: to evaluate: a) if the six minute walking test (6 MWD) induce DH reducing IC, b) if the reduction in IC is related to tidal expiratory flow limitation at rest (FL). Subjects and methods: Thirty eight stable COPD patients (28 FL and ten non FL during resting breathing, determined by the negative pressure technique). Inspiratory capacity was measured before and immediately after the 6 MWD test. Dyspnea, SpO2 and heart rate were measured before and after the test. Results: Inspiratory capacity was lower in FL patients as compared to patients without FL (p <0,005). Although no differences were found between groups in 6 MWD, dyspnea and HR, a significant reduction in IC after the walking test was observed only in FL patients (p <0,0001). In addition, SpO2 fell significantly (p <0,0001) after walking in the same group. Conclusions: Our results demonstrate that a moderate exercise such as the walking test induces DH and hypoxemia in patients with COPD and FL and stresses the importance of assessing DH by measuring IC in these patients (Rev Méd Chile 2001; 129: 1171-78) <![CDATA[Casos Clínicos Hamartoma hipotalámico, una causa de pubertad precoz: Caso clínico]]> Hypothalamic hamartomas are non neoplastic lesions that may cause precocious puberty with or without complex seizures, personality disorders and mental retardation. We report a 14 years old male that had a precocious puberty at the age of 11 and a prolonged episode of altered sensorium with automatism, that was diagnosed as a complex seizure. Physical examination showed a sexual development classified as Tanner stage III-IV, a height of 168 cm and a weight of 61 kg. Neurological examination was normal. A CAT scan showed a 13x13x9 mm mass in the suprasellar cistern, between the infundibulum and the brain stem, without exerting a mass effect over adjacent structures. It was diagnosed as an hypothalamic hamartoma (Rev Méd Chile 2001; 129: 1179-80) <![CDATA[Diabetes mellitus inducida por olanzapina: Caso clínico]]> Atypical antipsychotics are widely used in psychotic disorders, refractory to conventional neuroleptic agents. They induce minimal extra pyramidal side effects, probably due to their greater affinity for certain dopaminergic receptors. However, this polyreceptor affinity may be responsible for the development of other side effects. We report a 48 years old male drinker and addicted to cocaine, that after two months of Olanzapine use, developed a severe diabetes mellitus with fasting blood glucose values reaching 514 mg/dl. When he was admitted to the hospital, physical examination was normal and his body mass index was 28 kg/m2. Olanzapine was discontinued and blood glucose values gradually returned to normal. After two months of follow up, the patient is on dietary treatment and with a fasting glucose of 132 mg/dl (Rev Méd Chile 2001; 129: 1183-85) <![CDATA[Síndrome de Prader-Willi. Tratamiento con hormona de crecimiento en dos casos: <I>Report of two cases</I>]]> Prader-Willi syndrome (PWS) is a neurogenetic disorder caused by the absence or abnormal inactivation of a critical region of the paternal chromosome 15. Clinical manifestations include marked hypotonia at birth, progressive obesity that starts during the second year of life, stunting, hypogonadism and some dysmorphic features. Some of the symptoms and signs can be explained by growth hormone (GH) deficiency. We report two females aged 12 and 13 years old with PWS. Both were very short and obese, showed blunted GH responses to provocative stimuli and had low plasma levels of Insulin Growth Factor-1 (IGF-1). They have been on GH treatment for more than two years, demonstrating a marked growth acceleration, reduction in their fat mass, improvement of their muscular strength and an increase in their IGF-1 levels (Rev Méd Chile 2001; 129: 1186-90 <![CDATA[Derrame pericárdico masivo y taponamiento cardíaco como forma de presentación de hipotiroidismo: <I>Report of one case</I>]]> We report a 43 years old female, admitted due to fatigability, asthenia and diffuse adbominal pain. On admission, obesity, slowness of thinking, bradicardia, distention of jugular veins and ascites were observed on physical examination. Laboratory showed undetectable thyroid hormone levels, a chest X ray showed bilateral pleural effusion and an enlarged heart. An echocardiography showed a massive pericardial effusion with collapse of the right atrium and dilatation of both caval veins. A pericardial tap was performed, draining 350 ml. Thyroid hormone substitution was started and after 12 months of follow up, the heart size decreased and a control echocardiogram showed a minimal pericardial effusion (Rev Méd Chile 2001; 129: 1191-94) <![CDATA[Mortalidad por cáncer en Chile: consideraciones epidemiológicas]]> Malignancies are the second most important cause of mortality in Chile, accounting for 21.8% of total deaths. In comparison with other causes, cancer mortality shows an upward trend with increasing mortality rates from 99 to 118 per 100.000 population in the period 1980-1998. The most important cancer locations are stomach, lung and prostate among men and gallbladder, stomach, breast and uterine cervix in women. According to present risks, the mean probability for a Chilean to die from cancer is 3.0% for stomach, 2.3% for prostate, 2.0% for lung, 1.7% for gallbladder, 1.6% for breast and 1.2% for uterine cervix cancer. Recent trends of cancer crude death rates are a matter of concern. During the period 1990-1998 a significant decrease of death rates was only noticed for uterine cervix cancers. On the other hand, important increases were observed for prostate, lung, gallbladder, colon and kidney cancers. If death rates are adjusted by age, an increased risk, not due to the population aging process, is noticed for prostate and to less extent for kidney, colon, skin and myeloma. The adjusted rates show a downward trend for uterine cervix, stomach, breast and esophagus cancer. Increasing cancer mortality is associated with diagnostic and therapeutic delays. Possible actions in screening programs are discussed (Rev Méd Chile 2001; 129: 1195-1202). <![CDATA[Acido docosahexaenoico (DHA) en el desarrollo fetal y en la nutrición materno-infantil]]> Docosahexanoic acid (C22:6, DHA) is a highly unsaturated omega-3 fatty acid that forms part of the central nervous and visual system structures. DHA is synthesized from its precursor, alfa-linolenic acid, that is also a omega-3 fatty acid and can be obtained from vegetable oils. Marine organisms, specially fish, are good nutritional sources of DHA and eicosapentanoic acid (EPA), another omega-3 fatty acid that has a role in vascular homeostasis. DHA increases membrane fluidity, improving neurogenesis, synaptogenesis and the activity of retinal photoreceptors. The fetus, specially during the last trimester of pregnancy, has high DHA requirements. It is provided by the mother, since fetal DHA synthesis is negligible in this stage of development. Breast feeding provides DHA to the child, but most replacement artificial formulas do not provide this fatty acid. At the present moment, many products for infant nutrition contain DHA (Rev Méd Chile 2001; 129: 1203-11). <![CDATA[<I>Factores de riesgo no-tradicionales en la aterosclerosis</I>]]> During the last 10 years, several "non-traditional" risk markers for atherosclerosis have been identified. Among them, new markers of lipoprotein metabolism (ie lipoprotein [ a]), endothelial dysfunction (ie homocysteine), hemostasis (ie fibrinogen) and inflammation (ie C-reactive protein) have been linked to an excessive risk of cardiovascular disease. These factors should help the clinician to better identify individuals at risk of premature atherosclerotic disease and/or improve the predictive value of established risk factors for atherosclerosis. Finally, these factors are expected to improve the knowledge in the pathophysiology of cardiovascular diseases, and perhaps to impact future therapeutic decisions. In this review article, we will analyze the markers in which there are at least some evidence to support their acceptance as "non-traditional risk factors" for atherosclerotic disease (Rev Méd Chile 2001; 129: 1212-21)<hr/>Durante los últimos 10 años se han identificado varios marcadores de riesgo "no-tradicionales" para la aterosclerosis. Entre ellos, se ha relacionado con un riesgo excesivo de enfermedad cardiovascular a nuevos marcadores del metabolismo de lipoproteínas (ej: lipoproteína [a]), disfunción endotelial (ej: homocisteína), hemostasis (ej: fibrinógeno) e inflamación (ej: proteína C-reactiva). Estos factores deberían ayudar al clínico a identificar mejor los individuos con riesgo de una enfermedad aterosclerótica prematura y/o mejorar el valor predictivo de los factores de riesgo de aterosclerosis ya conocidos. Finalmente, se espera que estos factores aumenten el conocimiento de la fisiopatología y el diagnóstico de las enfermedades cardiovasculares y, tal vez, tengan impacto en futuras decisiones terapéuticas. En este artículo de revisión se analizan aquellos marcadores sobre los cuales existen algunas evidencias que apoyen su aceptación como "factores no-tradicionales de riesgo" para la enfermedad aterosclerótica <![CDATA[En relación a Cleopatra y los venenos de serpiente]]> Cleopatra VII, one of the last Egyptian sovereigns of the ptolomeic dynasty, is envisioned as a mythic figure, surrounded by intrigues and mystery. Her mysterious death was caused, according to history, by a snake bite. This article shows some instances of great Cleopatra's life and the state of the art on snake venoms. Even at the present time, snake bites are a public health problem in Asia, Africa, Central and South America, causing more than 25000 deaths every year. Most snake venoms have a protein structure and cause neurotoxic and hemolytic effects, altering coagulation and fibrinolysis. The mortality due to snake bites fluctuates between 1 and 22%. Specific treatment includes the use of specific antiserums with highly purified components (Rev Méd Chile 2001; 129: 1222-26).