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Biomedical subjects

S J Munoz

Publications and source records attributed to S J Munoz.

At least 19 recordsLinked to original sources
PubMed2001

Tacrolimus conversion improves hyperlipidemic states in stable liver transplant recipients.

With improvements in surgical technique and the advent of new and more effective immunosuppressive agents, survival rates in liver transplant recipients have dramatically improved. However, hyperlipidemia frequently develops in patients administered cyclosporine-based immunosuppression long-term, although it appears to occur less often with newer, tacrolimus-based regimens. We sought to determine whether an isolated change in the baseline immunosuppressive regimen (cyclosporine to tacrolimus) would improve hyperlipidemic states in these patients. Twenty-one long-term stable liver transplant recipients with hyperlipidemia, manifested by elevated cholesterol and/or triglyceride levels, were offered conversion to tacrolimus from cyclosporine A therapy. Lipid profiles were monitored at baseline (while on cyclosporine therapy) and at 1 and 3 months after conversion to tacrolimus therapy. There were no other medication manipulations. After conversion to tacrolimus therapy, mean cholesterol levels decreased from 251 to 202 mg/dL at 1 month (P <.001) and 194 mg/dL at 3 months (P <.001). Similarly, triglyceride levels decreased from 300 to 207 mg/dL by 1 month (P =.011) and 203 mg/dL by 3 months (P <.001). There was also a statistically significant decrease for very low-density lipoprotein levels at 3 months (P =.005) and low-density lipoprotein levels at 1 and 3 months (P =.013 and P =.014, respectively). High-density lipoprotein levels did not significantly change after conversion to tacrolimus therapy. Conversion was not accompanied by adverse side effects, and patients tolerated the change well. In conclusion, simple conversion from cyclosporine to tacrolimus-based immunosuppression therapy is safe and improves posttransplantation hyperlipidemia in a subgroup of liver transplant recipients.

Cholesterol↗
PubMed2000

Controlled non-heart-beating donor liver transplantation: a successful single center experience, with topic update.

BACKGROUND: The critical shortage of transplantable organs necessitates utilization of unconventional donors. We describe a successful experience of controlled non-heart-beating donor (NHBD) liver transplantation. METHODS: Controlled NHBDs had catastrophic head injury, prognosis for no meaningful recovery, decision to withdraw life support, and subsequent consent for donation. After stopping mechanical ventilation in the operating room, death determination by a nontransplant caregiver, and rapid aortic cannulation, liver and kidneys were recovered. RESULTS: Controlled NHBDs contributed 5% of hepatic allografts (8/164) from August 1996 through June 1999 (9% in 1998). Sixteen NHBDs afforded 8 livers and 24 kidneys. Liver donors (n=8) were 11-66 years old; half were >50 years old. Premortem alanine aminotransferase was 25-157 U/L. Arrest occurred 3-27 min after stopping ventilation. Perfusion started 3-5 min after incision, and <22 min after hypotension (mean arterial pressure: <50 mmHg). Patient and graft survivals are 100% at 18+/-12 months follow-up. There was no intraoperative complication, reperfusion syndrome, poor graft function, primary nonfunction, arterial thrombosis, biliary complication, or serious infection. Postoperative day 2 prothrombin time was 13+/-1 sec. Peak alanine aminotransferase was 980+/-601 U/L. Intensive care unit and posttransplant lengths of stay were 2+/-2 and 10+/-7 days, respectively. Soon after transplantation there was frequent temporary hyperbilirubinemia (five of eight recipients; bilirubin peak: 7-29 mg/dl, 2-3 weeks after transplantation) and rejection (4/8 recipients, <3 weeks after transplantation). CONCLUSIONS: NHBDs significantly and safely expanded our donor pool. NHBD surgeons must be capable of rapid procurement. Cautious liberalization of criteria for accepting livers from NHBDs with confounding risk factors is justified. Refined ethics guidelines would broaden approval of NHBDs.

Adolescent↗
PubMed2000

The outcome of acute hepatitis C predicted by the evolution of the viral quasispecies.

The mechanisms by which hepatitis C virus (HCV) induces chronic infection in the vast majority of infected individuals are unknown. Sequences within the HCV E1 and E2 envelope genes were analyzed during the acute phase of hepatitis C in 12 patients with different clinical outcomes. Acute resolving hepatitis was associated with relative evolutionary stasis of the heterogeneous viral population (quasispecies), whereas progressing hepatitis correlated with genetic evolution of HCV. Consistent with the hypothesis of selective pressure by the host immune system, the sequence changes occurred almost exclusively within the hypervariable region 1 of the E2 gene and were temporally correlated with antibody seroconversion. These data indicate that the evolutionary dynamics of the HCV quasispecies during the acute phase of hepatitis C predict whether the infection will resolve or become chronic.

Acute Disease↗
PubMed2000

Clinical predictors of pulmonary hypertension in patients undergoing liver transplant evaluation.

Clinical prediction of portopulmonary hypertension (PPHTN) is critical in the preoperative evaluation of candidates for orthotopic liver transplantation (OLT) because of its association with significant morbidity and mortality. To determine the clinical, laboratory, and echocardiographic predictors of PPHTN, we retrospectively evaluated 55 candidates before OLT. From those, 8 candidates had pulmonary hypertension ([HTN] group A) and 47 candidates did not (group B). Pulmonary HTN was defined as a mean pulmonary artery pressure (PAP) of 25 mm Hg or greater and either elevated pulmonary vascular resistance or normal pulmonary artery wedge pressure. The significant predictors of PPHTN were (1) systemic arterial HTN (63% in group A v 9% in group B; P <.001), (2) loud pulmonary component of the second heart sound (38% v 2%; P =. 001), (3) right ventricular (RV) heave (38% v 4%; P =.002), (4) RV dilatation by echocardiogram (63% v 0%; P <.001), (5) RV hypertrophy by echocardiogram (38% v 0%; P =.001), and (6) echocardiogram-estimated systolic PAP (SPAP) greater than 40 mm Hg (63% v 2%; P <.001). The sensitivity of these variables for the detection of pulmonary HTN ranges from 37% to 63%, and their specificity from 91% to 100%. We conclude that several clinical and echocardiographic features are significantly associated with pulmonary HTN in patients with cirrhosis. In particular, echocardiogram-estimated SPAP greater than 40 mm Hg is strongly associated with pulmonary HTN and is specific. These predictors, however, are not sensitive enough to identify all the patients with PPHTN. Therefore, the evaluation of a combination of these variables may be useful for the preoperative identification of pulmonary HTN in liver transplant candidates.

Case-Control Studies↗
PubMed2000

Long-term care of the liver transplant recipient.

Many liver transplant recipients are now reaching survival beyond 5 years from the liver transplant procedure, and many others are alive more than a decade from acquiring their new liver. Orthotopic liver transplant recipients enjoy the benefits of normal liver function, but a variety of metabolic and other medical problems often develop that require diagnosis and adequate management. These problems include hyperlipidemia, obesity, diabetes mellitus, renal disfunction, arterial hypertension, bone disease and neuropsychiatric syndromes. The gastroenterologist, internist, or local family physician is frequently called on to identify and treat these postoperative complications in conjunction with physicians at the transplant center.

Humans↗
PubMed1999

The effect of ursodeoxycholic acid on the florid duct lesion of primary biliary cirrhosis.

The frequency with which florid duct lesions are seen in needle-biopsy specimens of the liver was assessed in patients with primary biliary cirrhosis (PBC) enrolled in a 2-year randomized, double-blind, placebo-controlled trial of ursodeoxycholic acid (UDCA) versus placebo. Paired biopsy specimens obtained at entry and after 2 years on medication were reviewed blindly and mostly simultaneously by a panel of 5 hepatopathologists who, earlier, had characterized the florid duct lesion, which has been well described in the pathology literature. Florid duct lesions at entry were identified in approximately 36%. Patients with earlier disease showed florid duct lesions much more frequently than those with more advanced disease. The prevalence of florid duct lesions in 60 patients receiving placebo medication fell from 38.3% to 21.7%, P =. 025, over the period of 2 years. The prevalence of florid duct lesions also decreased in the 55 patients receiving UDCA, from 32.7% to 18.2%, P =.046. The prevalences of these lesions in the placebo and UDCA patients at entry and at 2 years were not significantly different from each other. The findings suggest that UDCA does not prevent ongoing bile duct destruction in patients with PBC. Instead, they support the impression that UDCA exerts its beneficial effects by protecting against the consequences of bile duct destruction.

Bile Ducts↗
PubMed1999

Experimental transmission of hepatitis C virus-associated fulminant hepatitis to a chimpanzee.

Hepatitis C virus (HCV) was transmitted from a patient with fulminant hepatitis C to a chimpanzee. The patient had developed two episodes of fulminant hepatitis C, each occurring after a separate liver transplantation. Serial serum and liver samples from the patient and the chimpanzee were analyzed for HCV replication, genotype, quasispecies heterogeneity, and antibodies. In the patient, the levels of HCV replication in serum and liver correlated with the degree of hepatocellular necrosis and the clinical expression of fulminant hepatitis. The same HCV strain, genotype 1a, was recovered from both episodes of fulminant hepatitis. An unusually severe acute hepatitis was also observed in the chimpanzee. The viruses recovered from the patient and the chimpanzee were almost identical and displayed relatively little quasispecies heterogeneity. Thus, the same HCV strain induced two episodes of fulminant hepatitis in a single patient and severe hepatitis in a chimpanzee, suggesting that the pathogenicity or virulence of a specific HCV strain may be important in the pathogenesis of fulminant hepatitis C.

Adult↗
PubMed1996

Interferon and other therapies for hepatitis B and hepatitis C infections.

Interferon is currently the only approved medication in the United States for treatment of chronic hepatitis B and C infections. The mechanism of action of interferon and guidelines for its administration are reviewed. Important clinical studies involving its use in hepatitis B and C infections are discussed, and investigational therapies for chronic viral hepatitis are highlighted.

Chronic Disease↗
PubMed1995

Histopathological heterogeneity in fulminant hepatic failure.

The clinicopathological features of 38 patients admitted consecutively for fulminant hepatic failure were studied. Histopathological material was reviewed in all patients. Both percutaneous and whole livers (either explanted or autopsy specimens) were available in 16 patients: whole livers only in 12 patients and biopsy specimens only in 10 patients. All patients were negative for antibodies to hepatitis C, whereas 24% had hepatitis B infection and 10% had adverse drug reactions. Livers from 75% of patients showed confluent hepatic necrosis. However, there was considerable variability in the extent of necrosis, and biopsy specimens from about 50% of the most severely affected livers showed only minimal bridging necrosis. In patients with massive hepatic necrosis, percutaneous liver biopsy specimens were frequently misleading because of regional inhomogeneities. Interestingly, five patients (13%) had established cirrhosis at the time of diagnosis. The best clinical predictors of survival were age and the maximal grade of encephalopathy. By contrast, neither the severity of confluent hepatic necrosis nor the etiology predicted the decision to transplant or the outcome. There were no differences in the histopathology corresponding to different etiologies. In summary, the approach to the patient with fulminant hepatic failure should be guided principally on clinical grounds, and further classification should be based on pathological and etiologic considerations. However, histological classification and prognosis based on percutaneous biopsy specimens alone may be misleading.

Adolescent↗
PubMed1994

Limonene in expired lung air of patients with liver disease.

As part of an effort to examine the relationship between chemosensory disturbance and oral chemistry, we analyzed expired lung air samples from a series of 24 patients with liver disease and 24 healthy controls using gas chromatography-mass spectrometry. Compared to samples from controls, lung air from patients with liver disease contained unusually high levels of limonene, a monoterpene that is a major component of the essential oil of citrus fruits (0.1 vs 7.0 micrograms/20 liters for controls and patients). Only half the patients showed high levels of limonene. Patients with noncholestatic liver disease were significantly more likely to have elevated lung air limonene levels than those with cholestatic liver disease (0.2 vs 13.8 micrograms/20 liters). Responses to food frequency and dietary behavior questionnaires indicated a pattern of diet selection and food preferences that were consistent with a dietary origin for the limonene in these patients.

Air↗
PubMed1994

Relationship between liver biochemical tests and dietary intake in patients with liver disease.

Relationships between liver biochemical test values and reported frequency of consumption of various foods were examined using a principal-component analysis of data from 42 patients with chronic liver disease. The statistical procedure identified relationships among biochemical and dietary variables. One relationship included the variables albumin, bilirubin, and frequency of intake of fruits and vegetables, starch, and meats. A relationship was also found between serum alkaline phosphatase (ALP) levels and fat/oil intake. Data from patients with primary biliary cirrhosis (PBC) and noncholestatic liver disease were compared using a correlational analysis. In patients with PBC, serum ALP levels were positively correlated with frequency of intake of fat/oil (r = 0.59, p < 0.01) and meats (r = 0.46, p < 0.05), whereas serum bilirubin (Bili) and aspartate aminotransferase (AST) levels were significantly correlated with frequency of intake of dairy products (rs = 0.48 and 0.45, ps < 0.05 for Bili and AST, respectively), meats (rs = 0.59 and 0.65, ps < 0.01), and fat/oil (r = 0.54, p < 0.02 and r = 0.48, p < 0.05). In patients with noncholestatic liver disease, Bili levels were correlated with frequency of intake of fat/oil (r = 0.58, p < 0.01), and fruits and vegetables (r = 0.68, p < 0.01). These results suggest that the degree of elevation of some liver biochemical tests in patients with liver disease may be affected by dietary intake.

Alkaline Phosphatase↗
PubMed1994

Hepatitis B virus precore mutation and fulminant hepatitis in the United States. A polymerase chain reaction-based assay for the detection of specific mutation.

Hepatitis B virus (HBV) variants with precore mutation(s) resulting in the absence of HBeAg production have been associated with the occurrence of fulminant hepatitis in Japan, Israel, and southern Europe, where the prevalence of this HBV strain appears common. In areas such as United States, where HBV infection is not endemic, the role of this mutant virus in fulminant hepatitis is unknown. We developed an amplification refractory mutation detection system to detect specifically the presence of the G to A mutation at nucleotide position 1898, which is the most frequently observed mutation resulting in a precore stop codon. In addition, this method provided a quantitative measurement of the relative ratio of one strain to the other. Using this system, we tested HBV strains for the presence of the stop codon mutation in sera from 40 cases of fulminant hepatitis B occurring in the United States. Serum HBV DNAs from 28 patients were analyzed successfully. A mixture of wild-type and mutant strains in various ratios were observed in 15 patients, wild type exclusively in 11, and mutant exclusively in 2. Four of these patients had undergone liver transplantation for HBV-associated cirrhosis and developed fulminant HBV-associated hepatitis after transplantation. Pre- and posttransplant serum samples from one patient were analyzed: a mixture of wild-type and mutant HBV strains was detected in both samples. Our study demonstrated that both wild-type and mutant HBV strains are associated with fulminant hepatitis, and that in some patients in the United States, factors other than precore mutations contribute to the development of fulminant hepatitis.

Adolescent↗
PubMed1993

Chemosensory function, food preferences and appetite in human liver disease.

We evaluated chemosensory function, food preferences, and appetite in 88 patients with liver disease including those with hepatitis, cirrhosis, primary biliary cirrhosis, and sclerosing cholangitis. Reported chemosensory disturbances were common in the patients with liver disease: over 40% reported recent taste changes, and 27% reported recent changes in smell, compared to only 6% of healthy, age- and gender-matched controls with no history of marked chemosensory malfunction. Compared to controls, a greater proportion of liver patients reported food cravings (47 vs. 17%) and food aversions (33 vs. 16%). Foods with a predominantly bitter taste were specifically less preferred in patients with liver disease compared to healthy controls. Patients were also more likely to report poor to fair appetite than controls (37 vs. 5%). Groups of patients with different types of liver pathology showed varying patterns of food preferences, suggesting that dietary recommendations to liver patients might be tailored to the altered preferences associated with a particular type of hepatic dysfunction.

Adult↗
PubMed1993

Rejection-independent cholangitis and cirrhosis following orthotopic liver transplantation.

The histologic diagnosis of extrahepatic biliary obstruction in the setting of orthotopic liver transplantation (OLT) may be complicated by nonobstructive factors, such as rejection, preservation injury, drug effects, and infection. Indeed, biopsy specimens from OLT patients frequently exhibit early posttransplant cholestasis, which is likely the result of several of these factors acting in concert. We reviewed the clinicopathologic features of 14 OLT patients whose biopsy specimens displayed prominent cholangitis with "obstructive"-type features. Cholangiograms, Doppler ultrasound examinations, and bacterial cultures were obtained in conjunction with all biopsy specimens. Despite histologic evidence of biliary obstruction, cholangiography revealed obstruction in only one case, leaks in four cases, and nine normal studies. Ten patients had severe systemic bacterial or cytomegalovirus infections. Biliary infection was documented in two cases. Hepatic artery occlusion was diagnosed in one case. The cholangitic pattern persisted in patients with unremitting infections, and two patients developed secondary biliary cirrhosis despite having consistently normal cholangiograms. Features of acute rejection or viral hepatitis were not observed on any biopsy specimen. The presence of this clinicopathologic spectrum was associated with a poor prognosis. Nine patients died and only four patients who responded to antibiotics survived. These findings demonstrate a striking cholangitic response to systemic infections in OLT grafts. The diagnosis of biliary obstruction in OLT liver biopsy specimens cannot be rendered without cholangiographic verification.

Adult↗
PubMed1993

Idiopathic hemochromatosis: MR imaging findings in cirrhotic and precirrhotic patients.

The authors reviewed T2-weighted and T2*-weighted abdominal magnetic resonance (MR) images in 19 pathology-proved cases of hepatic iron overload to compare patterns of iron distribution among cirrhotic and precirrhotic patients with idiopathic hemochromatosis (IH), as well as nontransfusional hepatic siderosis of other causes. Fifteen patients had clinical and laboratory evidence of IH. Four patients without IH had cirrhosis with moderate siderosis. In the MR images of all 19 patients, the liver had low signal intensity. The pancreas of 10 of 11 cirrhotic patients with IH had low signal intensity. All four precirrhotic patients with IH and all four cirrhotic patients without IH had pancreas with normal signal intensity at MR. Thus, pancreatic signal intensity was decreased only in cirrhotic patients with IH in this limited series. Conversely, pancreatic signal intensity is often normal in precirrhotic patients with IH prior to the development of cirrhosis, a stage at which definitive diagnosis by means of quantitative liver biopsy is important because early phlebotomy may prevent morbidity and mortality from IH. In cirrhotic patients with MR evidence of increased hepatic iron, the cause of cirrhosis is less likely to be IH if pancreatic signal intensity is normal.

Adult↗