Biomedical subjects

R K Seeto

Publications and source records attributed to R K Seeto.

5 recordsLinked to original sources

PubMed2000

Ischemic hepatitis: clinical presentation and pathogenesis.

BACKGROUND: The pathophysiology of ischemic hepatitis, otherwise known as "shock liver," is poorly understood, although it is believed to be the result of a reduction in systemic blood flow as typically occurs in shock. The aim of this study was to investigate the importance of this phenomenon as well as other clinical features in patients with ischemic hepatitis. METHODS: We identified a cohort of 31 patients (case group) who met the most commonly accepted definition of ischemic hepatitis (an acute reversible elevation in either the serum alanine or aspartate aminotransferase level of at least 20 times the upper limit of normal, excluding known causes of acute hepatitis or hepatocellular injury, in an appropriate clinical setting). We also evaluated the clinical features and serum aminotransferase levels in a cohort (the control group) of 31 previously healthy patients who sustained major nonhepatic trauma at San Francisco General Hospital, a major trauma center. Both groups of patients had documented systolic blood pressures <75 mm Hg for at least 15 minutes. Clinical and hemodynamic (invasive and noninvasive) data were recorded. RESULTS: Despite the marked reduction in blood pressure, no patient in the control group developed ischemic hepatitis. The mean (+/- SD) peak serum aspartate aminotransferase level in the control group was only 78 +/- 72 IU, in contrast with a mean peak of 2,088 +/- 2,165 IU in the case group. All 31 patients with ischemic hepatitis had evidence of underlying organic heart disease, 29 (94%) of whom had right-sided heart failure. CONCLUSIONS: Systemic hypotension or shock alone did not lead to ischemic hepatitis in any patient. The vast majority of patients with ischemic hepatitis had severe underlying cardiac disease that had often led to passive congestion of the liver. These data lead us to propose that right-sided heart failure, with resultant hepatic venous congestion, may predispose the liver to hepatic injury induced by a hypotensive event.

Acute Disease↗

PubMed1999

Amebic liver abscess: epidemiology, clinical features, and outcome.

Amebic liver abscess (ALA) is a serious, but readily treatable form of hepatic infection. In order to understand the clinical features of this condition in the United States, we reviewed the medical histories of 56 patients with ALA at two large San Francisco Hospitals from 1979 to 1994. Patients were divided into the following groups based on the presumed manner in which they had acquired ALA: those born or raised in the United States, with a history of travel to an endemic area (Tr-ALA); those from an endemic area, but living in the United States for less than one year (En-ALA); and those neither from nor having traveled to an endemic area (N-ALA). We found distinct clinical patterns in patients from different epidemiological groups. Patients with Tr-ALA were a decade older than those from endemic regions, were more likely to be male, and tended to have an insidious onset. Furthermore, compared to patients with En-ALA, those with Tr-ALA were more likely to have hepatomegaly (P < 0.0001) and large abscesses (ALA > 10 cm; P < 0.01). One third of the patients studied had no associated travel history or endemic origin as risk factors. Of these, 63% had a condition consistent with severe immunosuppression, such as infection with the human immunodeficiency virus (HIV), malnourishment with severe hypoalbuminemia, or chronic infection. In patients with N-ALA, the presence of a presumed immunosuppressed state increased significantly, as compared to patients with endemic or travel risk factors for ALA. During the last five years of the study, one third of all patients diagnosed with ALA were HIV positive (including 2 with a new diagnosis of AIDS), many of whom were discovered to be HIV-infected only after presentation with ALA. We conclude that travel to and origin in an endemic area are important risk factors for the development of ALA, and patients in these different epidemiological groups appear to have distinct clinical features. Further, in the absence of recognized risk factors, the development of ALA may suggest an immunocompromised host.

Adult↗

PubMed1997

Variations in the relative mRNA levels of actins and myosin heavy chains do not produce corresponding differences in their proteins in the adult human heart.

This paper examines the quantitative relationship between the expression of myosin heavy chain (MHC) and actin at both the levels of their mRNAs and their proteins. Explanted human left ventricle tissues were obtained from non-diseased (ND) individuals and from dilated cardiomyopathy (DCM) patients with terminally failing hearts who underwent heart transplantation. We found: (1) there are substantial differences in the stoichiometry of sarcomeric MHC and actin transcripts in hearts of DCM patients as well as in ND individuals; (2) there are substantial differences between levels of total sarcomeric actin transcripts from different individual patients; (3) by and large variations in transcript levels between samples from the same heart are much less than between samples from different hearts; and (4) the ratio of MHC to sarcomeric actin proteins expressed by different ND and DCM hearts remains essentially constant. We conclude that the human ventricle can accommodate a substantial imbalance between sarcomeric MHC and actin mRNA levels while maintaining a constant ratio of their corresponding proteins.

Actins↗

PubMed1996

Different electrophoretic techniques produce conflicting data in the analysis of myocardial samples from dilated cardiomyopathy patients: protein levels do not necessarily reflect mRNA levels.

A variety of electrophoretic techniques were used to search for potential causes of human dilated cardiomyopathy (DCM). Northern blots were used to quantify alpha-cardiac and alpha-skeletal muscle actins, and beta-myosin heavy chain mRNAs which are the predominant expressed isoform species. We found a wide range of mRNA levels expressed in both DCM and nondiseased (ND) samples of left ventricles. However, sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) gels of the same heart samples revealed a stable and constant ratio of actin and myosin. Dystrophin deficiency might account for the DCM symptoms and so dystrophin levels of DCM and ND samples were evaluated using Western blots probed with monoclonal antibodies for the N-, C- and mid-rod portions of this protein. We found that dystrophin levels were constant in all 29 DCM and 5 ND samples suggesting that dystrophin deficiency is probably not a contributing cause. We explored the possibility that terminal failure may be due to an apoptotic-like event in the cardiomyocytes. Zymograms of DCM and ND samples revealed a significant increase in DNase I activity in the DCM group compared to the ND samples. These data raise the possibility that end-stage failure may be associated with apoptosis.

Actins↗

PubMed1996

Pyogenic liver abscess. Changes in etiology, management, and outcome.

Pyogenic liver abscess (PLA) is an important entity with a changing clinical spectrum and may be more prevalent than previously reported. PLA remains most common in older patients, although we found a trend in age range downward. In contrast to earlier reports, PLA affected male and female patients with equal frequency. The most common known cause of PLA remains biliary tract disease, but the majority of patients with PLA were those in whom no underlying cause of PLA could be identified. Single PLA was more common than multiple PLA regardless of etiology. The clinical presentation of patients with PLA ia nonspecific and emphasizes the fact that a high index of suspicion is often required to make the diagnosis. Jaundice and a markedly elevated alkaline phosphatase are clues to the possibility of biliary tract involvement, but may not distinguish patients with liver abscess from those with other hepatic processes. While plain chest and abdominal X-rays were often abnormal and may point to the right upper quadrant as a source of abnormality, ultrasound (US) and abdominal computed tomography (CT) play a central role in this disease. Not only are they often paramount in elucidating the diagnosis of PLA, but US and CT are critical because of their ability to provide other useful information that may address the cause of PLA (that is the biliary tract, and in the case of abdominal CT, other structures). Further, our data suggest that in patients without clinical or imaging evidence of biliary tract disease or pylephlebitis, aggressive random evaluation of the intestinal tract is unwarranted. Percutaneous drainage combined with intravenous antibiotics was the most common therapeutic modality and resulted in cure in 76% of all patients in which it was used (compared to 65% with antibiotics alone and 61% with surgery) and has been successful in 90% of patients over the last 5 years (n = 50). In this study, percutaneous catheter drainage (PCD) appeared to result in a higher cure rate than percutaneous needle aspiration (PNA) but comparative studies are required to further address and determine their relative efficacies. Intravenous antibiotics alone are an important option in carefully selected patients. Surgical intervention as a primary mode of therapy has been almost completely replaced by less invasive approaches such as PCD/PNA, but remains an important consideration in patients who fail these therapies. Although PLA was once considered a fatal disease, the prognosis is now excellent. We have identified a subgroup of patients with no or low-level elevations in bilirubin and alkaline phosphatase and most often single right-sided PLA who do not have a readily identifiable cause of PLA (that is, cryptogenic), as having a particularly favorable prognosis. Death due to PLA is now limited primarily to those patients with severe underlying disease processes, including malignancy.

Adolescent↗