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1.
Clin Chem Lab Med ; 52(6): 899-909, 2014 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-24406287

RESUMEN

BACKGROUND: Hyper-methylation of CpG dinucleotides in the promoter region of inhibitor of cyclin-dependent kinase 4A (INK4A) has been reported in 60%-80% of hepatocellular carcinoma (HCC). As INK4A promoter hypermethylation event occurs early in HCC progression, the quantification of INK4A promoter methylation in blood sample may represent a useful biomarker for non-invasive diagnosis and prediction of response to therapy. METHODS: We examined INK4A promoter methylation using circulating cell-free DNA (ccfDNA) in a total of 109 serum specimens, including 66 HCC and 43 benign chronic liver diseases. Methylation of the individual seven CpG sites was examined using pyrosequencing. RESULTS: Our results showed that there were significantly higher levels of methylated INK4A in HCC specimens than controls and that the seven CpG sites had different levels of methylation and might exist in different PCR amplicons. The area under receiver operating characteristic (ROC) curve was 0.82, with 65.3% sensitivity and 87.2% specificity at 5% (LOD), 39.0% sensitivity and 96.5% specificity at 7% LOD, and 20.3% sensitivity and 98.8% specificity at 10% LOD, respectively. CONCLUSIONS: Our results support additional studies incorporating INK4A methylation testing of ccfDNA to further validate the diagnostic, predictive, and prognostic characteristics of this biomarker in HCC patients. The knowledge of the existence of epi-alleles should help improve assay design to maximize detection.


Asunto(s)
Carcinoma Hepatocelular/genética , Inhibidor p16 de la Quinasa Dependiente de Ciclina/genética , Metilación de ADN , ADN/sangre , Neoplasias Hepáticas/genética , Regiones Promotoras Genéticas/genética , Análisis de Secuencia de ADN/métodos , Alelos , Secuencia de Bases , Carcinoma Hepatocelular/sangre , Línea Celular Tumoral , Islas de CpG/genética , ADN/genética , Humanos , Neoplasias Hepáticas/sangre
2.
World J Hepatol ; 3(8): 205-10, 2011 Aug 27.
Artículo en Inglés | MEDLINE | ID: mdl-21954408

RESUMEN

The treatment of choice for patients with severe alcoholic hepatitis (AH) is use of corticosteroids. Many randomized well designed studies have been reported from all over the world on the use of corticosteroids in the treatment of AH. However, the data on the efficacy of corticosteroids in these patients have been conflicting. Initial meta-analyses also failed to show beneficial effects of corticosteroids. Based on individual data meta-analysis showing clear benefit of corticosteroids amongst patients with severe AH (modified discriminant function of 32 or more), led American College of Gastroenterology to recommend use of corticosteroids as the first line treatment option amongst patients with severe AH. However, corticosteroids are relatively contraindicated amongst patients with severe AH and coexistent sepsis, gastrointestinal bleeding, and acute pancreatitis. These patients may be candidates for second line treatment with pentoxifylline. Further, specific treatment of AH with corticosteroids far from satisfactory with as many as 40%-50% of patients failing to respond to steroids, thus classified as non-responsive to steroids. The management of these patients is a continuing challenge for physicians. Better treatment modalities need to be developed for this group of patients in order to improve the outcome of patients with severe AH. This article describes at length the available trials on use of corticosteroids and pentoxifylline with their current status. Route of administration, dosage, adverse effects, and mechanisms of action of these two drugs are also discussed. Finally, an algorithm with clinical approach to management of patients who present with clinical syndrome of AH is described.

3.
World J Hepatol ; 3(8): 211-4, 2011 Aug 27.
Artículo en Inglés | MEDLINE | ID: mdl-21954409

RESUMEN

Patients with severe alcoholic hepatitis (AH) need to be treated with specific treatment for better outcome. Currently available specific treatment modalities are use of corticosteroids or pentoxifylline. However, the response rate to these drugs is only about 50%-60%. Hence, there is an urgent need for better and more effective treatment options. Tumor necrosis factor plays an important role in the pathogenesis of AH. However, agents blocking the action of tumor necrosis factor have not been found to be effective. Rather the randomized studies evaluating these agents showed an adverse effect and more infections in treated patients. Critical role of tumor necrosis factor in hepatic regeneration explaining this contrast is discussed. Oxidative stress and inflammation derived from gut bacteria ate two main components in the pathogenesis of AH laying foundation for the role of antioxidants, probiotics, and antibiotics in the management of AH. This article reviews the current data and status of these newer agents for the treatment of AH. Of the various options available, Vitamin E and N-acetylcysteine (NAC) have shown great promise for clinical use as adjunct to corticosteroids. With these encouraging data, future well designed studies are suggested to assess Vitamin E and NAC before their routine use in clinical practice in the management of AH.

4.
Dig Dis Sci ; 55(5): 1230-40, 2010 May.
Artículo en Inglés | MEDLINE | ID: mdl-19629688

RESUMEN

PURPOSE: Measurement of portal venous pressure in patients with portal hypertension is important to assess efficacy of beta blockers in patients with esophageal varices. Currently, the gold standard for measurement of portal venous pressure is the estimation of hepatic venous pressure gradient (HVPG). Being an invasive technique, serial measurements of HVPG are not feasible in clinical practice. In this respect, duplex Doppler ultrasound (DDUS) examination is an upcoming non-invasive technique for the estimation of portal venous and splanchnic hemodynamics. The aim of the present review is to analyze the current literature focusing on how the two techniques compare to each other in terms of assessing the portal pressure and assessing pitfalls in the current technique. RESULTS: Duplex Doppler ultrasound (DDUS) currently has limitations in measuring the portal pressure in a non-invasive way. Hemodynamic venous and arterial indices measured on DDUS correlate with the HVPG. The technique has been refined, however, there is no uniform surrogate marker that can be used in clinical practice. CONCLUSIONS: More studies are needed in order to remove the shortcomings in the current technique. The target is to be able to measure the actual portal pressure or at least derive an ideal venous or arterial hemodynamic surrogate marker having close correlation with the HVPG.


Asunto(s)
Hipertensión Portal/diagnóstico por imagen , Sistema Porta/diagnóstico por imagen , Ultrasonografía Doppler Dúplex , Cateterismo , Hemodinámica , Humanos , Hipertensión Portal/fisiopatología , Sistema Porta/fisiopatología
5.
World J Gastroenterol ; 15(29): 3681-3, 2009 Aug 07.
Artículo en Inglés | MEDLINE | ID: mdl-19653349

RESUMEN

Bilhemia or bile mixing with blood is a rare clinical problem. The clinical presentation is usually transient self-resolving hyperbilirubinemia, progressive and rapidly rising conjugated hyperbilirubinemia, or recurrent cholangitis. Endoscopic retrograde cholangiopancreatography (ERCP) plays an important role in diagnosis and management. Biliary decompression with endoscopic sphincterotomy is useful in treating these patients. If not recognized and treated in time, the condition can be fatal in a significant proportion of patients. This usually occurs after blunt or penetrating hepatic trauma due to a fistulous connection between the biliary radicle and portal or hepatic venous radical. Cases have been described due to iatrogenic trauma such as liver biopsy and percutaneous biliary drainage. However, the occurrence after trans-jugular intra-hepatic porto-systemic shunt (TIPS) is very rare. We report a case of bilhemia presenting as rapidly rising bilirubin after TIPS. The patient was managed successfully with ERCP and removal of a blood clot from the common bile duct.


Asunto(s)
Bilirrubina/sangre , Colangiopancreatografia Retrógrada Endoscópica , Derivación Portosistémica Intrahepática Transyugular/efectos adversos , Anciano , Bilis , Femenino , Humanos , Complicaciones Posoperatorias/sangre , Complicaciones Posoperatorias/cirugía
6.
Public Health Rep ; 124(1): 120-6, 2009.
Artículo en Inglés | MEDLINE | ID: mdl-19413034

RESUMEN

OBJECTIVES: The incidence of hepatocellular carcinoma (HCC) in the United States has increased dramatically over the last two decades, largely because of an increase in the number of people with advanced hepatitis C virus (HCV) infection. U.S. prisoners are at high risk for HCC, given their elevated rates of HCV infection, comorbid hepatitis B virus (HBV) infection, and alcoholic liver disease. The purpose of our study was to examine the prevalence and mortality of HCC in the nation's largest state prison system. METHODS: The study population consisted of 325,477 male Texas Department of Criminal Justice (TDCJ) inmates who were incarcerated between January 1, 2003, and July 31, 2006. Information on medical conditions and demographic characteristics was obtained from an institution-wide medical information system. RESULTS: During the 3.5-year study period, 176 male TDCJ inmates (54 per 100,000) were diagnosed with HCC and 108 (33 per 100,000) died as a result of HCC. Inmates who were Hispanic, older, and infected with HCV, HBV, or human immunodeficiency virus had elevated rates of both HCC prevalence and mortality. After adjusting for all study covariates, HCC prevalence, but not mortality, was modestly elevated among inmates with diabetes. CONCLUSIONS: Our study showed that the Texas male prison population had a sevenfold higher prevalence of HCC than the general U.S. male population and a fourfold higher death rate from HCC. These findings likely reflect the high concentration of HCC-related risk factors, particularly HCV, among prisoners.


Asunto(s)
Carcinoma Hepatocelular/mortalidad , Neoplasias Hepáticas/mortalidad , Prisioneros , Adolescente , Adulto , Anciano , Humanos , Sistemas de Información , Masculino , Persona de Mediana Edad , Texas/epidemiología , Adulto Joven
8.
Ann Hepatol ; 6(4): 204-7, 2007.
Artículo en Inglés | MEDLINE | ID: mdl-18007548

RESUMEN

The treatment of autoimmune hepatitis is evolving as the natural history of the disease and newer agents become available. This concise review will outline the various treatment options in these patients. Treatment with current corticosteroids and azathioprine works in most patients but issues of intolerance and incomplete response arise. These situations led to the investigation of newer immunosupressants including mycophenolate mofetil, budesonide cyclosporine, tacrolimus and ursodeoxycholic acid. The newer agents have been studied in small patient numbers so they are not first-line treatment yet but do have a clear role in those patients with intolerance of incomplete response to standard corticosteroids and azathioprine.


Asunto(s)
Corticoesteroides/uso terapéutico , Hepatitis Autoinmune/tratamiento farmacológico , Inmunosupresores/uso terapéutico , Corticoesteroides/administración & dosificación , Hepatitis Autoinmune/inmunología , Humanos , Inmunosupresores/administración & dosificación
9.
J Pediatr Surg ; 42(10): 1677-82, 2007 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-17923195

RESUMEN

BACKGROUND: In the United States, cholesterol stones account for 70% to 95% of adult gallstones and black pigment stones for most of the remainder. Calcium carbonate stones are exceptionally rare. A previous analysis of a small number of pediatric gallstones from the north of England showed a remarkably high prevalence of calcium carbonate stones. The aims of this study were to analyze a much larger series of pediatric gallstones from our region and to compare their chemical composition with a series of adult gallstones from the same geographic area. METHODS: A consecutive series of gallbladder stones from 63 children and 50 adults from the north of England were analyzed in detail using Fourier transform infrared microspectroscopy. Demographic and clinical data were collected on all patients. The relative proportions of each major stone component were assessed: cholesterol, protein and calcium salts of bilirubin, fatty acids, calcium carbonate, and hydroxyapatite. RESULTS: Thirty-nine (78%) adults had typical cholesterol stones, 7 (14%) had black pigment bilirubinate stones, and only 2 (4%) had calcium carbonate stones. In contrast, 30 (48%) children had black pigment stones, 13 (21%) had cholesterol stones, 15 (24%) had calcium carbonate stones, 3 (5%) had protein dominant stones, and 2 (3%) had brown pigment stones. In children, cholesterol stones were more likely in overweight adolescent girls with a family history of gallstones, whereas black pigment stones were equally common in boys and girls and associated with hemolysis, parenteral nutrition, and neonatal abdominal surgery. Calcium carbonate stones were more common in boys, and almost half had undergone neonatal abdominal surgery and/or required neonatal intensive care. CONCLUSION: The composition of pediatric gallstones differs significantly from that found in adults. In particular, one quarter of the children in this series had calcium carbonate stones, previously considered rare. Geographic differences are not the major reason for the high prevalence of calcium carbonate gallstones in children.


Asunto(s)
Carbonato de Calcio/análisis , Colelitiasis/química , Adolescente , Adulto , Factores de Edad , Bilirrubina/análisis , Niño , Preescolar , Colelitiasis/epidemiología , Colestasis Extrahepática/complicaciones , Colesterol/análisis , Comorbilidad , Conducto Cístico , Inglaterra/epidemiología , Ácidos Grasos/análisis , Femenino , Hemólisis , Humanos , Masculino , Sobrepeso , Nutrición Parenteral/efectos adversos , Proteínas/análisis , Factores de Riesgo , Espectroscopía Infrarroja por Transformada de Fourier
10.
Ann Epidemiol ; 17(10): 808-13, 2007 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-17689260

RESUMEN

OBJECTIVES: Information on the epidemiology of end-stage liver disease (ESLD) in US correctional populations is limited. We examined the prevalence, mortality and clinical characteristics of ESLD in the nation's second largest state prison system. METHODS: We collected and analyzed medical and demographic data from 370,511 offenders incarcerated in Texas' prison system during a 3.5-year period. RESULTS: ESLD was diagnosed in 484 inmates (131/100,000); 213 (57/100,000) died of ESLD. Offenders who were Hispanic, 30-49 years of age, > or =50 years of age, HIV monoinfected, hepatitis C virus (HCV) monoinfected, or HIV/HCV coinfected had elevated ESLD prevalence and mortality rates. CONCLUSIONS: ESLD mortality in Texas' prison population is approximately 3 times higher than that of the general population, reflecting elevated rates of HCV and HIV/HCV coinfection among prisoners. Ultimately, the only viable treatment option for many prisoners with ESLD will be liver transplantation. The enormous costs of organ transplantation and immunosuppressive therapy are staggering and have the potential to decimate the healthcare budgets of most prison systems. Consequently, it is imperative that correctional healthcare programs expand HCV treatment and prevention strategies.


Asunto(s)
Hepatopatías/epidemiología , Hepatopatías/mortalidad , Prisioneros , Adulto , Estudios de Cohortes , Femenino , Infecciones por VIH/diagnóstico , Infecciones por VIH/epidemiología , Hepacivirus , Hepatitis C/diagnóstico , Hepatitis C/epidemiología , Humanos , Hepatopatías/diagnóstico , Masculino , Persona de Mediana Edad , Texas/epidemiología
11.
Clin Chim Acta ; 381(2): 119-23, 2007 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-17442291

RESUMEN

BACKGROUND: Multiple serum markers to estimate hepatic fibrosis in chronic liver disease have been proposed. The AST/Platelet Ratio Index (APRI) is a simple biochemical index that has been shown to be useful and accurate in about 50% of patients with chronic hepatitis C. We determined if the combination of the APRI and the FIBROSpect II, a commercially available hepatic fibrosis marker that measures 3 components of the extracellular hepatic matrix, would further help distinguish mild from significant fibrosis in a group of patients with chronic hepatitis C. METHODS: In an outpatient setting, 93 consecutive patients were studied who were undergoing staging liver biopsy for chronic hepatitis C who had a liver biopsy length>or=1.5 cm. All had blood drawn at the time of the biopsy. Liver biopsies were staged for fibrosis by the Batts Ludwig criteria (F0-F4). Patients with previous anti-viral therapy, hepatocellular carcinoma, an organ transplant, or co-infection with HIV or hepatitis B were excluded. The APRI was calculated and FIBROSpect II determined. RESULTS: The AUC of the ROC curve for the APRI and FIBROSpect II were 0.887 and 0.879 respectively. Using cutoffs of or=1.2 for significant fibrosis, the APRI correctly estimated 19 of 20 patients with mild fibrosis for an NPV of 95.0%, and 31 of 33 patients with significant fibrosis for a PPV of 93.6%. The FIBROSpect II also works best utilizing 2 cutoffs, and using cutoffs of or=85 it correctly identified 18 of 18 patients with mild fibrosis and all 26 patients with significant fibrosis for an NPV and PPV of 100% for both. Among the 40 patients who could not be classified by the APRI, an additional 16 could be correctly classified using the FIBROSpect II with cutoffs of or=85. This lowered the indeterminate zone from 43.0 to 25.8%. By combining the APRI and the FIBROSpect II, the AUC for the ROC curve improved significantly to 0.931 (p=0.013). CONCLUSIONS: The APRI and the FIBROSpect II are both accurate tests for separating mild from significant fibrosis. By using the APRI as the initial screen, >50% of patients with mild or significant fibrosis can be correctly identified. If the patient falls in the indeterminate zone, then the more expensive FIBROSpect II could be obtained. This strategy could decrease the number of liver biopsies.


Asunto(s)
Aspartato Aminotransferasas/sangre , Hepatitis C Crónica/diagnóstico , Hepatitis C Crónica/patología , Cirrosis Hepática/diagnóstico , Cirrosis Hepática/patología , Pruebas de Función Hepática/métodos , Recuento de Plaquetas , Adulto , Alanina Transaminasa/sangre , Femenino , Genotipo , Hepatitis C Crónica/genética , Humanos , Cirrosis Hepática/etiología , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Curva ROC
12.
Pediatr Surg Int ; 23(3): 219-23, 2007 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-17225180

RESUMEN

In contrast to adults, calcium carbonate gallstones are relatively common in children. Their pathogenesis is poorly understood. Cystic duct obstruction promotes calcium carbonate formation in bile and increases gallbladder mucin production. We tested the hypothesis that mucin producing epithelial cells would be increased in gallbladders of children with calcium carbonate gallstones. Archival gallbladder specimens from 20 consecutive children who had undergone elective cholecystectomy for cholelithiasis were examined. In each case, gallstone composition was determined by Fourier transform infrared microspectroscopy. Gallbladder specimens from six children who had undergone cholecystectomy for conditions other than cholelithiasis during the same period were used as controls. Multiple sections were examined in a blinded fashion and scored semiquantitatively for mucin production using two stains (alcian blue and periodic acid-Schiff). Increased mucin staining was observed in 50% or more epithelial cells in five gallbladder specimens from seven children with calcium carbonate stones, compared to 5 of 13 with other stone types (P = 0.17) and none of the control gallbladders (P = 0.02). Gallbladders containing calcium carbonate stones were significantly more likely than those containing other stone types or controls to contain epithelial cells with the greatest mucin content (P = 0.03). Gallbladders containing calcium carbonate stones were also more likely to show the ulcer-associated cell lineage. These results demonstrate an increase in mucin producing epithelial cells in gallbladders from children containing calcium carbonate stones. This supports the hypothesis that cystic duct obstruction leading to increased gallbladder mucin production may play a role in the development of calcium carbonate gallstones in children.


Asunto(s)
Carbonato de Calcio , Vesícula Biliar/metabolismo , Cálculos Biliares/química , Cálculos Biliares/etiología , Mucinas/metabolismo , Adolescente , Niño , Preescolar , Epitelio/metabolismo , Epitelio/patología , Femenino , Vesícula Biliar/patología , Cálculos Biliares/patología , Cálculos Biliares/cirugía , Humanos , Lactante , Masculino , Membrana Mucosa/metabolismo , Membrana Mucosa/patología
13.
J Clin Gastroenterol ; 40(6): 535-42, 2006 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-16825937

RESUMEN

GOALS: To evaluate the aspartate aminotransferase/platelet ratio index (APRI) as a predictor of the presence or absence of significant fibrosis on liver biopsy of patients with chronic hepatitis C (HCV). BACKGROUND: The decision to treat HCV is often made on the basis of the presence or absence of significant fibrosis on the liver biopsy. Because liver biopsy is expensive and invasive a noninvasive marker to evaluate hepatic fibrosis would be useful. The APRI is an easy to calculate index that is one of several markers that have been proposed. STUDY: We retrospectively reviewed the charts of 339 patients with chronic HCV who had liver biopsies from January 2000 to March 2003. We subsequently evaluated 151 patients receiving pretreatment evaluation liver biopsies who had serum aspartate aminotransferase, platelets, routine liver function tests, and demographic data obtained. All liver biopsies were staged by the Batts Ludwig criteria. RESULTS: The area under the curve of the receiver operator characteristics of the calculated APRI compared with the liver biopsy demonstrated that the fibrosis score was 0.889 in the prospective group and 0.790 in the retrospective group. To achieve predictive values of approximately 90%, useful cutoffs were found at 0.40 and 1.5 in the retrospective study, and 0.42 and 1.2 in the prospective study leaving intermediate zones of 58.9% and 41.1%, respectively. In the prospective group, 34 of 36 patients with a value of <0.42 were accurately predicted as having mild fibrosis, whereas 50 of 54 patients with a value >1.2 were accurately predicted to have significant fibrosis. CONCLUSIONS: The APRI is a good estimator of hepatic fibrosis and was more accurate in a prospective group than a retrospective one. It potentially could be used to decrease the number of liver biopsies.


Asunto(s)
Aspartato Aminotransferasas/sangre , Hepatitis Crónica/diagnóstico , Cirrosis Hepática/diagnóstico , Pruebas de Función Hepática/métodos , Recuento de Plaquetas , Adulto , Alanina Transaminasa/sangre , Área Bajo la Curva , Biomarcadores/sangre , Femenino , Hepatitis Crónica/sangre , Humanos , Cirrosis Hepática/sangre , Cirrosis Hepática/etiología , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Estudios Prospectivos , Curva ROC , Reproducibilidad de los Resultados , Estudios Retrospectivos
14.
J Vasc Interv Radiol ; 17(2 Pt 1): 373-8, 2006 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-16517786

RESUMEN

The authors describe a patient with bleeding varices due to chronic portal vein occlusion. A transjugular intrahepatic portosystemic shunt (TIPS) attempt failed because of cannulation of a low-pressure network of portal veins, which communicated only with the chronically thrombosed native portal vein. A second TIPS attempt was successful after transhepatic catheterization of a high-pressure portal system that was continuous with periportal collateral veins and mesenteric veins. After 8 months and one TIPS revision for hepatic vein stenosis, the patient has improved liver function, collapsed varices, and a patent TIPS on ultrasonogram. This case illustrates that cavernous transformation of the portal vein may result in variable intrahepatic portal perfusion and pressures and that TIPS in such cases requires careful selection of an intrahepatic portal vein to achieve adequate portal decompression.


Asunto(s)
Hipertensión Portal/cirugía , Vena Porta , Derivación Portosistémica Intrahepática Transyugular , Trombosis de la Vena/cirugía , Anciano , Enfermedad Crónica , Femenino , Humanos , Hipertensión Portal/etiología , Radiografía Intervencional , Trombosis de la Vena/complicaciones
16.
J Vasc Interv Radiol ; 14(10): 1251-7, 2003 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-14551271

RESUMEN

PURPOSE: To determine whether hepatic perfusion patterns predict mortality after transjugular intrahepatic portosystemic shunt (TIPS) creation in patients with severe ascites. MATERIALS AND METHODS: This retrospective study included 22 patients who had enhanced cine magnetic resonance (MR) imaging performed immediately before TIPS creation in the angled coronal plane including the left kidney, liver, and main portal vein. Regions of interest were centered over the liver and kidney, and perfusion curves were generated and reviewed before the standard TIPS procedure was performed. Four patients did not undergo TIPS creation as a result of very poor hepatic perfusion by MR. All patients were followed clinically and by ultrasound surveillance of their shunt. RESULTS: Eleven patients died within 6 months, including all four patients who did not have a TIPS because of MR evidence of poor hepatic perfusion. Of these 11 patients, eight (73%) had unfavorable liver flow consisting of diminished enhancement compared to the kidney and early peak enhancement of less than 50 seconds. The surviving patients all showed a delayed peak enhancement of greater than 50 seconds. CONCLUSIONS: In patients undergoing TIPS creation for refractory ascites, blunted arterial-type hepatic enhancement is a poor prognostic sign. Cine MR imaging with evaluation of hepatic perfusion can be performed and reviewed before the TIPS procedure. Alternative techniques for ascites reduction may be preferred for patients with unfavorable hepatic perfusion.


Asunto(s)
Ascitis/cirugía , Circulación Hepática , Derivación Portosistémica Intrahepática Transyugular , Ascitis/diagnóstico , Ascitis/etiología , Femenino , Humanos , Riñón/patología , Hígado/patología , Fallo Hepático/complicaciones , Fallo Hepático/mortalidad , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Vena Porta/patología , Pronóstico , Estudios Retrospectivos , Factores de Riesgo , Tasa de Supervivencia
17.
J Pediatr ; 142(4): 435-40, 2003 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-12712064

RESUMEN

During a 5-year period (1997-2002) 20 consecutive children (11 boys; median age, 8 years; range, 0.3-13.9 years) underwent cholecystectomy for cholelithiasis at a regional pediatric surgical center. Multiple stones were present in 16 patients (80%). All stones were collected prospectively. Composition studies were performed after grinding an aliquot of stone and examining a layer of crushed powder by Fourier transform infrared microspectroscopy. The relative proportions of each major stone component were assessed: cholesterol, protein and calcium salts of bilirubin, fatty acids, carbonate, and hydroxyapatite. Of the 20 children, 10 had black pigment stones, 2 had cholesterol stones, 1 had brown pigment stones, and 7 had calcium carbonate stones; the latter are exceptionally rare in adults. The composition of pediatric gallstones in this series differs from that found in adults.


Asunto(s)
Colecistectomía , Colelitiasis/química , Colelitiasis/cirugía , Adolescente , Adulto , Factores de Edad , Niño , Preescolar , Femenino , Humanos , Lactante , Masculino , Estudios Prospectivos , Índice de Severidad de la Enfermedad , Espectroscopía Infrarroja por Transformada de Fourier
18.
Chemistry ; 8(23): 5323-31, 2002 Dec 02.
Artículo en Inglés | MEDLINE | ID: mdl-12432500

RESUMEN

Strong electronic Raman bands corresponding to the transition between 4I9/2 and 4I11/2 manifolds of Nd3+, caused by a Raman-enhancement effect, are observed in the FT-Raman spectrum of Nd2O3. Neither resonance enhancement (RR) nor surface enhancement (SERS) accounts for the Raman enhancement observed here. We propose a new mechanism of Raman enhancement called the "feed-back" mechanism. A YAG laser excites the final state of the Raman transition (4I11/2 of Nd3+) to the 4F3/2 state and causes a significant decrease in the population of Nd3+ at the 4I11/2 state. This causes the population ratio of Nd3+ at 4I9/2 and 4I11/2 to deviate from the value required by Boltzmann's law. To restore equilibrium, Raman scattering is enhanced so that more Nd3+ ions are brought from the 4I9/2 state to the 4I11/2 state. This hypothesis gets support from the temperature-variable FT-Raman spectroscopic results. Additionally, obvious differences between the Stokes and anti-Stokes Raman spectrum of Nd3+ provide further evidence to support the feed-back mechanism. The Raman-enhancement effect confers on the electronic Raman bands a special ability to reflect the variation of coordinated structure around metal ions. The structural variations in polymer-metal ion composites and biomineralization systems have been investigated by using the electronic Raman bands.

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