RESUMEN
The Los Azufres geothermal complex of central Mexico is characterized by fumaroles and boiling hot-springs. The fumaroles form habitats for extremophilic mosses and ferns. Physico-chemical measurements of two relatively pristine fumarolic microcosms point to their resemblance with the paleo-environment of earth during the Ordovician and Devonian periods. These geothermal habitats were analysed for the distribution of elemental mass fractions in the rhizospheric soil (RS), the native volcanic substrate (VS) and the sediments (S), using the new high-sensitivity technique of polarized x-ray energy dispersive fluorescence spectrometry (PEDXRF) as well as instrumental neutron activation analysis (INAA) for selected elements. This work presents the results for the naturally occurring heavy radioactive elements (NOHRE) Bi, Th and U but principally the latter two. For the RS, the density was found to be the least and the total organic matter content the most. Bi was found to be negligibly present in all substrate types. The average Th and U mass fractions in the RS were higher than in the VS and about equal to their average mass fractions in the S. The VS mass fraction of Th was higher, and of U lower, than the mass fractions in the earth's crust. In fact for the fumaroles of one site, the average RS mass fractions of these elements were higher than the averaged values for S (without considering the statistical dispersion). The immobilization of the NOHRE in the RS is brought about by the bio-geochemical processes specific to these extremophiles. Its effectiveness is such that despite the small masses of these plants, it compares with, or may sometimes exceed, the immobilization of the NOHRE in the S by the abiotic and aggressive chemical action of the hot-springs. These results indicate that the fumarolic plants are able to transform the volcanic substrate to soil and to affect the NOHRE mass fractions even though these elements are not plant nutrients. Mirrored back to the paleo times when such plant types were ubiquitous, it would mean that the first plants contributed significantly to pedogenesis and the biogeochemical recycling of even the heaviest and radioactive elements. Such plants may potentially be useful for the phytostabilisation of soil moderately contaminated by the NOHRE. Furthermore where applicable, geochronology may require taking into account the influence of the early plants on the NOHRE distributions.
Asunto(s)
Elementos Radiactivos/análisis , Ecosistema , México , Torio/análisis , Uranio/análisisAsunto(s)
Conductos Biliares/anatomía & histología , Colecistectomía/historia , Cirugía General/historia , Anatomía/historia , Conductos Biliares/cirugía , Historia del Siglo XV , Historia del Siglo XVI , Historia del Siglo XVII , Historia del Siglo XVIII , Historia del Siglo XIX , Historia del Siglo XX , Historia Antigua , HumanosRESUMEN
BACKGROUND: Intestinal obstruction is one of the leading causes of admission to emergency wards around the world, and its etiology has changed over the past century. AIM: The goal of this study was to ascertain the causes of intestinal obstruction at our Institution and compare the results with other reports of Mexican, U.S., and Canadian hospitals. METHODS: Retrospective review of a cohort of patients with intestinal obstruction operated on between 1985 and 2000. Demographic data and operative findings were obtained. RESULTS: Our cohort included 452 patients, 55.3% were women; mean age for the entire group was 54 years. The obstruction was located in the small bowel in 86.9% of cases and the leading causes were adhesions (58.6%), hernia (16.1%) and neoplasia (13.9%). Other etiologic factors had a low incidence that varied between 4.4 and 0.22%. CONCLUSIONS: The most common causes of intestinal obstruction are similar to those reported in the U.S., British and Canadian medical literature. Some tertiary-level Mexican institutions showed the same incidence of etiology, but some large general hospitals in Mexico City showed etiologic factors reported 100 years ago by the current so-called developed countries, i.e., that the same socioeconomic conditions existed in both population groups nearly a century apart.
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Obstrucción Intestinal/etiología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios RetrospectivosRESUMEN
OBJECTIVE: To find out when and where the hospitals began, its history and evolution. MATERIAL: Review of books and Journals of personal and Instituto Nacional de la Nutrición Salvador Zubirán, libraries about history of medicine and surgery. RESULTS: During the last 5000 years the history of man has been full of events, the beginning and development of hospitals has been one of them. Everything started in Sumeria in 3500 bC, some changes were developed in Egypt, Greece and Rome. In the 4th century aD the first true hospitals are opened. Since then the hospitals had improved until now. CONCLUSIONS: The sick man has been looking for the healing of his ailments, and few places made him feel protected as the hospital does. The birth, growing and evolution of such institutions had been slow and steady until the end of the second millennium aD.
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Hospitales/historia , Historia del Siglo XV , Historia del Siglo XVI , Historia del Siglo XVII , Historia del Siglo XVIII , Historia del Siglo XIX , Historia del Siglo XX , Historia Antigua , Historia MedievalRESUMEN
INTRODUCTION: Symptomatic gastroesophageal reflux (GER) occurs in 0-20% of patients treated with pneumatic dilation and in 5-30% with cardiomyotomy. However, the prevalence of GER evaluated with esophageal pH-monitoring is unknown. AIM: To investigate the frequency of GER in achalasia patients treated with pneumatic dilation or myotomy. MATERIAL AND METHODS: Patients with achalasia were evaluated prospectively and classified in 4 groups: group A = treated with pneumatic dilation; group B = treated with open abdominal myotomy; group C = transthoracic myotomy; and group D = submitted to laparoscopic abdominal myotomy with antireflux procedure. Esophageal manometry and 24 h pH-monitoring were performed in all patients. GER was defined as a pH < 4 in more than 4% of the total time. RESULTS: Thirty-one patients, 22 women and 9 men, with a mean age of 44.7 years were evaluated. Nine patients had GER symptoms and 22 were asymptomatic. GER was detected with pH-metry in 42% of the total group: 33% for group A, 75% for group B, 44% for group C and none for group D. CONCLUSIONS: Prevalence of GER in achalasia patients treated with pneumatic dilation and surgical myotomy was high. We suggest the inclusion of 24 hr esophageal pH-metry in the follow-up due to the significant prevalence of asymptomatic GER. Minimal hiatus dissection and antireflux procedure were surgical factors related with a lower frequency of GER after achalasia myotomy.
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Cateterismo , Acalasia del Esófago/terapia , Reflujo Gastroesofágico/prevención & control , Complicaciones Posoperatorias/prevención & control , Adulto , Anciano , Acalasia del Esófago/cirugía , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios ProspectivosRESUMEN
OBJECTIVE: To evaluate the utility of surgery in the treatment of peptic ulcer disease. METHODS: The clinical history of patients operated for peptic ulcer disease in a 15 year period were reviewed. The demographic data, indications for surgery, surgical procedure, morbidity, mortality and long term results, were analyzed. RESULTS: 349 patients were operated for peptic ulcer disease or its complications, 56% male. In 78% surgery was elective, mostly due to pyloric obstruction. In the remaining 22% perforation or bleeding ulcer were the main causes for emergency surgery. The most frequent elective procedure was vagotomy and drainage (66%); in urgent surgery, a definitive procedure was done in 35% of the perforations and in 94% of the bleeding ulcers. The 30-day mortality in urgent surgery was 14%; in elective surgery there was no mortality. A satisfactory long term result was obtained in 80% of the patients. CONCLUSIONS: An indication for surgical treatment of complicated peptic ulcer disease was above 50%, and 90 per cent in recent years. The frequency of urgent surgery is increasing and reached 60% of surgeries for this disease. Whenever possible, a definitive procedure is recommended.
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Úlcera Péptica/cirugía , Procedimientos Quirúrgicos Electivos , Urgencias Médicas , Femenino , Humanos , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Estudios RetrospectivosRESUMEN
BACKGROUND: The different surgical approaches of Zenker's diverticulum are controversial. AIM: To analyze the results of the surgical management of Zenker's diverticulum. METHODS: The charts of patients with surgical treatment of Zenker's diverticulum were reviewed in a retrospective fashion. The demographic and clinical data, surgical indication and procedures, operative morbidity and mortality and results were analyzed. RESULTS: There were 15 patients, 12 men and 3 women with an average age of 68 years. All of them reported cervical dysphagia, 93 per cent regurgitation and 60 per cent upper airway symptoms. The barium esophageal study was diagnostic in all patients. Cricopharyngeal myotomy was performed in all patients and diverticulopexy (60 per cent) or diverticulectomy (40 per cent) was accomplished. There were one mucosal perforation during the myotomy but three esophageal fistula were developed during the first postoperative week. All three received medical treatment with healing between the 7th to 21st postoperative day. One patient suffered acute myocardial infarction and there were no deaths. During the follow-up in 14 patients (93.3 per cent) disappearance of symptoms were reported, in the remaining patient minimal dysphagia was present. CONCLUSIONS: The surgical treatment of Zenker's diverticulum should be performed in symptomatic patients. The esophageal X-ray study is the best diagnostic tool. The cricopharyngeal myotomy is the keystone in the surgical treatment and may be complete with inversion, diverticulectomy or diverticulopexy according with the physical and clinical characteristics of diverticulum and the patient. There were excellent results in more than 90 per cent of the operated patients, with a low morbidity and no mortality.
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Divertículo de Zenker/cirugía , Anciano , Anciano de 80 o más Años , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Radiografía , Estudios Retrospectivos , Factores de Tiempo , Divertículo de Zenker/diagnóstico , Divertículo de Zenker/diagnóstico por imagenRESUMEN
BACKGROUND: Mucocele is a cystic dilatation of the vermiform appendix that contains mucous material. It may be caused by benign or malignant diseases. AIM: To report and discuss four cases with mucocele. REPORT OF CASES: The main clinical manifestations were abdominal pain and changes in the bowel habits. In two cases, appendiceal mucocele was an incidental finding in the diagnostic work-up or operation for acute diverticulitis and acute cholecystitis, respectively. The diagnostic approach included barium enema and CT scan of the abdomen. In three cases, the mucocele was secondary to mucinous cystadenoma; two of them had a preoperative diagnosis of mucocele and underwent colonic preparation and right hemicolectomy, one patient underwent appendectomy alone. The remaining case underwent appendectomy alone, was found to have mucinous adenocarcinoma, and underwent a right hemicolectomy in a second operation. Postoperative outcome was adequate in all cases. CONCLUSION: Mucocele of the vermiform appendix is a rare disease. An appendectomy is an adequate treatment for benign disease. If malignant disease is demonstrated, a right hemicolectomy should be performed.
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Apéndice , Mucocele , Adulto , Anciano , Anciano de 80 o más Años , Apendicectomía , Neoplasias del Apéndice/complicaciones , Neoplasias del Apéndice/diagnóstico , Neoplasias del Apéndice/cirugía , Enfermedades del Ciego/diagnóstico , Enfermedades del Ciego/etiología , Enfermedades del Ciego/cirugía , Colectomía , Cistoadenoma Mucinoso/complicaciones , Cistoadenoma Mucinoso/diagnóstico , Cistoadenoma Mucinoso/cirugía , Femenino , Humanos , Masculino , Persona de Mediana Edad , Mucocele/diagnóstico , Mucocele/etiología , Mucocele/cirugía , Tomografía Computarizada por Rayos XRESUMEN
The alkaline single cell gel (SCG) assay is a sensitive electrophoretic technique for detecting the presence of DNA single strand breaks and alkali-labile damage in individual cells. This technique was used to assess and compare the level of DNA damage in peripheral blood leukocytes/lymphocytes from well-nourished children with infection, well-nourished children with infection and under drug treatment, and from malnourished infected children with and without previous drug treatment. The present study shows that severe infection is associated with a significant increase in DNA damage. The average migration length was five times greater in severely infected well-nourished children compared to that found in healthy, well-nourished children. The results obtained in this study indicate that malnutrition is another factor associated with an increase in DNA migration. The average tail length for malnourished, severely infected children was twice as great as that obtained for cells from well-nourished, severely infected children. We also detected a variable increase in DNA migration associated with treatment for severe infection. Nevertheless, the excessive heterogeneity, the concurrent number of drugs used and the limited size of the treated population precludes an accurate assessment of which drugs were involved in the increase in DNA damage. Further studies will be necessary involving a large number of patients to address the relation between levels of DNA damage and specific kinds of infection, various drug treatments, and the type and severity of malnutrition. The increased level of DNA damage in severely infected and malnourished children could be related to negative effects such as a deficient immune response resulting in an increased susceptibility to malignant transformation.
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Daño del ADN , Infecciones/genética , Trastornos Nutricionales/genética , Niño , Preescolar , Electroforesis , Femenino , Humanos , Lactante , Leucocitos/química , Linfocitos/química , MasculinoRESUMEN
During an 11 year period, 47 patients with acute acalculous cholecystitis were operated on. Two to one male/female ratio was observed with a mean age of 55 age of 55 years. No one had a past history of biliary tract pathology but 70 per cent of the patients had risk factors, mainly diabetes mellitus, cardiovascular and collagenous diseases, some different of those reported in the world literature (sepsis, trauma, non biliary tract surgery, etc.). The ultrasound was the best diagnostic tool. Open cholecystectomy was performed in all patients and some sort of local complication was found in 85 per cent of patients (empyema, gangrene or perforation) in spite of the surgical procedure was done on emergency or early elective basis, a 31 per cent operative mortality rate was found and a 10.6% Operative mortality rates was observed. The bacterial cultures showed gram negative and anaerobic flora. This report shows that an early diagnosis and surgical treatment keeps a low morbidity and mortality rates but the gallbladder late complications have a high rates.
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Colecistitis/cirugía , Enfermedad Aguda , Adulto , Anciano , Anciano de 80 o más Años , Colecistitis/complicaciones , Femenino , Humanos , Masculino , Persona de Mediana Edad , Complicaciones Posoperatorias/epidemiología , Estudios RetrospectivosRESUMEN
A transversal retrolective analysis of all patients undergoing surgical treatment for cholelithiasis and choledocholithiasis between 1980 and 1987 was performed. The aim of the study was to investigate risk factors for the development of postoperative complications and mortality in elderly patients. A group of 187 patients above 70 years old were comparatively analyzed with 962 younger patients (total group: 1,149). Medical records were evaluated with emphasis to the diagnosis, associated diseases, characteristics of the surgical treatment, postoperative complications and mortality. Fifty percent of the elderly patients presented one or more concomitant diseases which significantly contributed to their operative risk. Acute cholecystitis, choledocholithiasis and cholangitis were more frequently found in aged patients (p < 0.05). In this group more patients also required bile duct exploration (p < 0.005). Major complications occurred in 16% and nine developed wound infection (5%). Operative mortality was 5.3%. In contrast, operative mortality of patients under 70 years of age was 1.5% and postoperative complications occurred infrequently. Acute cholecystitis, congestive heart failure, a history of myocardial infarction, and liver insufficiency were found as specific risk factors in the elderly.
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Colelitiasis/cirugía , Factores de Edad , Anciano , Anciano de 80 o más Años , Colelitiasis/complicaciones , Colelitiasis/mortalidad , Estudios Transversales , Femenino , Humanos , Masculino , Complicaciones Posoperatorias/mortalidad , Análisis de Regresión , Estudios Retrospectivos , Factores de RiesgoRESUMEN
The aim of this retrospective study was to evaluate the impact of resident participation in the results of surgical treatment in 1149 consecutive patients operated for biliary disease between January, 1980 and December, 1987 at the Instituto Nacional de la Nutrición "Salvador Zubirán". Patients were divided in three groups: GROUP I. 640 cases treated by surgical residents under a senior surgeon supervision. GROUP II. 168 patients operated by the chief surgical resident. GROUP III. 341 patients treated by senior staff surgeons. Age, sex and risk factors were similar between groups. Residents performed more operative cholangiograms (p less than 0.05). In general, senior surgeons performed more transduodenal sphincteroplasties (p less than 0.05) and other additional procedures like appendectomies and gastrostomies during the same surgery. Wound infection was more frequent in group III patients (p less than 0.005) but there was no significant clinical difference in other postoperative complications like intraabdominal abscess, bile fistula, wound dehiscence, intraabdominal bleeding, iatrogenic injury of the biliary tract, and residual common duct stone. The duration of the in-hospital convalescence period was similar in all three groups. The mortality rate for the total series was 2.2%. In group II there were more patients affected for acute cholecystitis, and more patients died postoperatively (p = less than 0.01). We may consider this difference attributable to the more complex patients handled by the chief resident. Mortality rate among patients with chronic biliary tract disease was less than 1%. We were not able to demonstrate any significant difference in mortality and complication rates between those patients operated by residents, chief residents and senior surgeons.(ABSTRACT TRUNCATED AT 250 WORDS)
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Colelitiasis/cirugía , Internado y Residencia , Estudios de Evaluación como Asunto , Femenino , Humanos , Masculino , Estudios RetrospectivosRESUMEN
This is a retrospective review of 10 consecutive patients with intra-abdominal complications of typhoid fever requiring surgical treatment, during a four-year period at the Instituto Nacional de la Nutrición Salvador Zubirán. There were 7 males and 3 females with an average age of 33.9 years. In 80 per cent of the cases Salmonella typhi was obtained in blood and bone narrow cultures. Five cases developed terminal ileum perforations, 4 massive bleeding related to ulcerated typhoid ileitis and one patient was operated on with the preoperative diagnosis of acute abdomen during the course of severe, toxic, typhoid fever. At laparotomy, no abnormalities were found. Five patients were treated with right hemicolectomy, 3 with local resections and primary closure, and another one, with segmental terminal ileum resection and end to end anastomosis. One patient died of mixed shock and multiple organ failure. This event was secondary to partial dehiscence of the ileo-transverse anastomosis and massive bleeding. Four patients had complications; a) pneumonia, b) urinary tract infection, c) splenic abscess that required splenectomy and: d) intestinal obstruction. All patients were treated with chloramphenicol. We found a high morbidity and mortality rate of the typhoid fever complications. The surgical resection and specific antibiotic therapy are the most effective treatment, however, complications can appear during its treatment.
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Fiebre Tifoidea/complicaciones , Adolescente , Adulto , Anciano , Femenino , Enfermedades Gastrointestinales/epidemiología , Enfermedades Gastrointestinales/etiología , Enfermedades Gastrointestinales/mortalidad , Enfermedades Gastrointestinales/cirugía , Humanos , Masculino , México/epidemiología , Persona de Mediana Edad , Reoperación/estadística & datos numéricos , Estudios Retrospectivos , Fiebre Tifoidea/epidemiología , Fiebre Tifoidea/mortalidad , Fiebre Tifoidea/cirugíaRESUMEN
Transduodenal sphincteroplasty is a surgical procedure indicated for treatment and prophylaxis of biliary tract stones and Oddi's sphincter fibrosis. This report analyzes the experience in Mexico City at Instituto Nacional de la Nutrición "Salvador Zubirán", in the last 35 years. We report the indications, morbidity and mortality rates, risk factors which have influence in the final outcome, as well as the long term effectivity. We used the chi-square analysis for measuring this correlation. Sphincteroplasty was effective for long term biliary permeability in 93%. Mortality rate was 4.3% and we had complications in 25.9%. In 150 biopsies, we found histological abnormalities in 90%. Presence of cholangitis was a risk factor for mortality, and serum albumin less than 3 g/dl for developing biliar or duodenal fistulas (p less than 0.02). Patients with chronic pancreatic disease in which sphincteroplasty was performed had poor outcome, compared with patients who had only biliary tract stones or Oddi's sphincter fibrosis. We concluded that transduodenal sphincteroplasty is an effective surgical procedure which supplies long term biliary tract permeability with a real present therapeutic value.