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Biomedical subjects

R Rubin

Publications and source records attributed to R Rubin.

At least 253 records · Page 14Linked to original sources
PubMedDate not supplied

MR imaging of hepatic iron overload in rat.

To investigate the relationship of hepatic signal intensity and T2 with histologic grading in an animal model of oral iron overload and to determine the duration of feeding necessary to produce abnormalities detectable on magnetic resonance (MR) images, hepatic iron overload was induced in 12 rats by feeding them a diet supplemented with 4% carbonyl iron for 2-11 weeks. Iron overload seen on MR images was graded independently and blindly by two radiologists as normal, mild, moderate, or severe. The rats were killed, and histologic findings were graded blindly by four pathologists using a similar subjective scale. Hepatic T2 values were estimated from spin-echo images. In the rats with iron overload, intracellular iron deposition was noted on histologic studies. On MR images, hepatic signal intensity and T2 decreased after only 2 weeks of dietary iron overload, and both continued to decrease with longer duration of feeding. There was significant correlation between iron overload duration and changes on MR images and between MR images and histologic grading (r = .92, P = .0001 for both). The mean T2 of hepatic iron overload decreased with longer duration of feeding.

Animals↗
PubMedDate not supplied

Cirrhosis: multiobserver analysis of hepatic MR imaging findings in a heterogeneous population.

To investigate the magnetic resonance (MR) imaging findings of hepatic cirrhosis and the potential of MR imaging in differentiating cirrhosis from other hepatic abnormalities, three observers with different levels of expertise in MR imaging (specialist, experienced radiologist, and novice with special training) reviewed hepatic MR imaging examinations of 52 patients with biopsy-proved presence (n = 29) or absence (n = 23) of cirrhosis. All examinations included motion-compensated T1-weighted, T2-weighted, and flow-sensitive gradient-echo images. For all three observers, linear signal irregularity was more accurate than other findings. For the final diagnosis of cirrhosis, the specialist was most sensitive (76% at high threshold, 97% at low threshold), followed by the novice with special training (31% and 79%, respectively). Specificity was 100% for all observers at high threshold and 78%, 96%, and 87% for expert, experienced, and trained novice observers, respectively, at low threshold. Sensitivity did not vary regardless of severity of fibrosis, as determined independently by a hepatopathologist. MR imaging has the potential of offering a comprehensive noninvasive evaluation of patients with suspected cirrhosis, but considerable expertise is required at present.

False Positive Reactions↗
PubMedDate not supplied

MR imaging of hepatic nodular regenerative hyperplasia.

Nodular regenerative hyperplasia (NRH), a rare condition that is commonly associated with noncirrhotic portal hypertension, is not well described in the MR literature. Three patients at two institutions were identified who had both abdominal MR imaging and pathologic evidence of NRH. All examinations were performed at 1.5 T and included axial T1- and T2-weighted spin-echo (SE) images. The MR studies were reviewed by two radiologists in consensus. Two patients had multiple liver lesions that had high signal components on T1-weighted images and were predominantly isointense with liver on the T2-weighted images. One patient had no focal lesions identified. NRH, when visualized on MR images, appears as multifocal masses with shortened T1 and T2 similar to liver. NRH should be considered in the differential diagnosis of hepatocellular tumors, especially in patients with a predisposing condition.

Adult↗
PubMedDate not supplied

Pyogenic liver abscess: studies of therapy and analysis of risk factors.

Experience with 46 patients diagnosed with liver abscesses over a 13-year period was reviewed to ascertain the impact of percutaneous versus surgical drainage. In most of the cases the abscesses were diagnosed by sonography or computed tomography. The most common pathogenetic mechanism was ascending biliary tract infection. Of the 46 total patients, 27 were primarily treated surgically, whereas 19 underwent percutaneous drainage. In the surgical group five (18.5%) patients required reoperation. Percutaneous drainage failed in four patients (21.1%). Multivariate stepwise logistic regression analysis revealed that a high APACHE II score, low hemoglobin level, and high serum bilirubin level were significant predictors of a complicated clinical course. Death was related more closely to the overall condition of the patient, as expressed by a high APACHE II score, and the underlying disease (malignancy) than to the mode of therapy.

Adult↗
PubMedDate not supplied

Sinusoidal spread of liver metastases from renal cell carcinoma: simulation of diffuse liver disease on MR imaging.

Rarely, hepatic metastases can simulate hepatic infiltrative diseases. We present a case of a patient with advanced metastatic renal cell carcinoma who developed hepatomegaly and clinical signs of hepatocellular injury. On magnetic resonance imaging, the injury simulated a diffuse process, e.g., acute fulminant viral or chemical hepatitis or drug toxicity. Despite its high resolution, magnetic resonance imaging might not depict focal lesions in patients with extensive metastases. In correlation with clinical history, malignant disease should be considered when diffusely abnormal hepatic signal intensity is noted.

Carcinoma, Renal Cell↗
PubMedDate not supplied

Significance of the computed tomography finding of subcapsular hepatic necrosis in liver transplantation.

BACKGROUND: To evaluate the clinical significance of the computed tomographic finding of subcapsular hepatic necrosis following liver transplantation. METHODS: 105 computed tomography scans performed in 50 allografts, 6 days to 4 years following transplantation, were retrospectively reviewed and divided into two groups: those with and those without the computed tomographic finding of subcapsular hepatic necrosis. Extrahepatic fluid, biliary dilatation, circumcaval rings, periportal collar, biochemistry, and random biopsies were correlated with the computed tomographic finding of subcapsular hepatic necrosis. RESULTS: Computed tomographic finding of subcapsular hepatic necrosis was demonstrated at some point in 21 (42%) patients and was never demonstrated in 29 (58%) patients. The association of periportal collar with the computed tomographic finding of subcapsular hepatic necrosis was significant; there was no significant association with other computed tomographic findings. There was no significant difference in serum transaminases between the two groups. There was no significant difference in necrosis on biopsy between the two groups; however, the association of acute cellular rejection with the computed tomographic finding of subcapsular hepatic necrosis was significant. CONCLUSIONS: Computed tomographic finding of subcapsular hepatic necrosis is a common finding following liver transplantation, which has little clinical prognostic significance.

Biopsy, Needle↗
PubMedDate not supplied

Psychiatric disease and cytomegalovirus viremia in renal transplant recipients.

Although cytomegalovirus (CMV) is rarely cultured from peripheral-blood leukocytes of immunocompetent patients, it may be cultured from up to 60% of renal transplant recipients, 1 to 4 months after transplantation. During this same period, renal transplant recipients are often referred for psychiatric evaluation. Since CMV may infect the central nervous system, the relationship between isolation of CMV from peripheral-blood leukocytes (viremia) and psychiatric evaluation was investigated in 80 renal allograft recipients at the Massachusetts General Hospital. Five of 16 (31%) patients with viremia and 7 of 64 (11%) patients without viremia required psychiatric consultation (P = 0.04, two-tailed Fisher exact test). CMV viremia may be an important but treatable contributor to psychiatric symptoms in the transplant recipient.

Cytomegalovirus↗
PubMedDate not supplied

Metabolism of procainamide to a hydroxylamine by human neutrophils and mononuclear leukocytes.

The chronic use of procainamide is associated with a high incidence of drug-induced lupus and also agranulocytosis. We have previously demonstrated that procainamide is metabolized in the liver to reactive hydroxylamine (PAHA) and nitroso (nitroso-PA) metabolites which covalently bind to protein and are toxic to lymphocytes. We proposed that these metabolites were responsible for the toxicities of procainamide. However, PAHA and nitroso-PA do not appear to escape the liver in significant concentrations. In this paper we describe the metabolism of procainamide to a reactive hydroxylamine by neutrophils and mononuclear leukocytes. Such metabolism only occurs if the cells have been stimulated to have a respiratory burst. These observations have obvious possible implications for the mechanism of procainamide-induced agranulocytosis (formation of a reactive metabolite by neutrophils) and procainamide-induced lupus (formation of a reactive metabolite by monocytes). The metabolism of drugs to reactive metabolites by monocytes may be a general mechanism for hypersensitivity reactions because monocytes play a key role in the processing of antigen and stimulation of antibody synthesis.

Biotransformation↗
PubMedDate not supplied

Hepatocellular tumors with high signal on T1-weighted MR images: chemical shift MR imaging and histologic correlation.

We reviewed conventional and chemical shift MR images and histologic findings of seven proven primary hepatic masses that had higher signal than liver on T1-weighted images to determine if this necessarily indicates fat and if the presence of fat indicates malignancy. These seven masses included five hepatocellular carcinomas (HCCs), one focal nodular hyperplasia (FNH), and one fatty dysplastic nodule. An eighth solitary high signal mass without histologic proof had evidence of abundant fat on each of two chemical shift MR images 25 months apart. Only one of the five HCCs had chemical shift or histologic evidence of fat, while the FNH and dysplastic nodule each had both chemical shift and histologic confirmation of fat. The dysplastic nodule became more dysplastic and grew significantly within 14 months, but remained benign. The unproven fatty lesion decreased in size over 25 months and is therefore presumably benign. Although no statistical inferences can be drawn from this small correlative study, we have shown that HCC may have higher signal intensity than liver on T1-weighted images, whether or not it contains fat. Chemical shift techniques can confirm the presence of intratumoral fat and thus indicate a mass of hepatocellular origin, but the mass may be benign or malignant.

Biopsy↗
PubMedDate not supplied

[A case report of drepanocytic anemia with "belt syndrome"].

Following article describes the case of a child with painful abdominal symptomatology showing characteristics of an acute abdomen. Following the laboratory tests abdominal crises have been classified as vessel occlusion crises with sickle cell anemia.

Abdomen, Acute↗
PubMedDate not supplied

Recovery of native liver after heterotopic liver transplantation for fulminant hepatic failure: MR studies.

Heterotopic liver transplantation involves the transplantation of an auxiliary liver into the subhepatic space while leaving the native liver intact. This procedure is a viable treatment for select patients with fulminant hepatic failure who fail medical treatment. The MR-pathologic correlation of a patient who developed graft failure and recovered full function of her native liver after heterotopic liver transplantation is presented. Based on the imaging and biopsy findings, immunosuppression was withdrawn and the patient remains asymptomatic with normal liver function. Interpreters of imaging studies in this group of patients should not restrict their attention to the heterotopic graft. The return of the native liver in both a structural and functional sense is a clinically important phenomenon that can be detected with MR imaging.

Adult↗
PubMedDate not supplied

[Evaluation of the therapeutic effectiveness of orally administered fenoterol in asthmatic children].

In a single blind controlled trial we evaluated the effectiveness of fenoterol, administrated by oral route, in 14 pediatric patients, suffering from allergic asthma. The study was designed through three cycles of therapy: the first with fenoterol (0.25 mg/kg), the second with placebo and the third with the active drug again. The duration of each period was of one month and every two weeks a clinical and spirometric evaluation were performed. Positive data with statistically significant differences for the spirometric parameters were found together with a good safety and tolerability.

Administration, Oral↗