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A S Klein

Publications and source records attributed to A S Klein.

78 records · Page 5Linked to original sources
PubMed1976

The DNAs of the A and B chromosomes of the mealy bug, Pseudococcus obscurus.

When the DNA of mealy bugs carrying B chromosomes (+B:DNA( was compared to the DNA of individuals not possessing Bs (-B:DNA), no significant differences were found using isopycnic centrifugations in CsCl or thermal denaturation analyses. Both DNAs had buoyant densities of 1.693 g/cm3 in neutral CsCl gradients and 1.748 g/cm3 in alkaline CsCl gradients. Satellite DNAs were not detected. The average Tm of +B:DNA was 67.9 degrees C in 0.1 SSC while -B:DNA had an average Tm of 67.4 degrees C in the same solution. However, in situ molecular hybridizations with complementary RNAs (cRNAs) transcribed in vitro from each type of DNA showed considerable differences with regard to the amount of labeling of B chromosomes. Using cRNA to +B:DNA, the average number of silver grains over a B chromosome was 2.1 X the average number of silver grains over individual non-B chromosomes (A chromosomes). In contrast, the ratio (B/A) using cRNA to -B:DNA was less than 0.14. The results are interpreted as meaning that very little DNA is shared in common by both A and B chromosomes.

Animals↗
PubMedDate not supplied

Diagnosis and management of cholangiocarcinoma in primary sclerosing cholangitis.

Cholangiocarcinoma remains difficult to diagnose and is a major cause of death in patients with primary sclerosing cholangitis. Recently serum carcinoembryonic antigen and carbohydrate antigen 19-9 (CA 19-9) levels have been reported to improve diagnostic accuracy in patients with cholangiocarcinoma and primary sclerosing cholangitis. We reviewed our experience with cholangiocarcinoma complicating primary sclerosing cholangitis to identify clinical factors associated with cholangiocarcinoma in patients with primary sclerosing cholangitis and to determine the appropriate management of patients with confirmed or suspected cholangiocarcinoma. Between 1984 and 1997, 25 patients (18%) were diagnosed with cholangiocarcinoma among 139 patients with primary sclerosing cholangitis. The diagnosis of primary sclerosing cholangitis was made coincident with the diagnosis of cholangiocarcinoma in 12 patients and preceded it by a mean of 62 months in the remaining 13 patients. The incidence of inflammatory bowel disease was higher (P <0.05) in patients with cholangiocarcinoma (80% vs. 61%). Nine patients (36%) with cholangiocarcinoma were managed with either extrahepatic bile duct resection and/or partial hepatic resection (n = 5) or liver transplantation (n = 4), and the remaining 16 patients were unresectable at presentation. Serum CA 19-9 was elevated in all six patients with cholangiocarcinoma who were analyzed and in none of the eight patients without cholangiocarcinoma who were tested (P <0.01). Actuarial 1- and 3-year survival rates in the resected patients (56% and 28%, respectively) were significantly longer (P <0. 02) than in the unresected patients (13% and 0%, respectively). The 10-year actuarial mortality rates for cholangiocarcinoma among all 139 patients was 25%. In summary, cholangiocarcinoma was the leading cause of death in patients with primary sclerosing cholangitis and was often diagnosed concurrently with or within months of its diagnosis. Early liver transplantation for patients with primary sclerosing cholangitis will not reduce the incidence of cholangiocarcinoma-related mortality in these patients.

Actuarial Analysis↗
PubMedDate not supplied

Immunohematologic complications of ABO-unmatched liver transplants.

Transplantation of ABO-unmatched livers has been associated with the development of donor-derived antibody (DDAb) and hemolysis. Nine (22%) of 41 consecutive patients undergoing liver transplantation at our institution received 10 ABO-unmatched livers. Five (56%) of nine patients developed DDAbs and hemolysis. All five patients were group A1 and received group O livers. DDAbs appeared a mean of 9.2 +/- 2.8 (1 SD) days after surgery and persisted for 15.2 +/- 10.3 days. All patients with DDAbs developed hemolysis. During the period when DDAbs were demonstrable, the hemoglobin dropped by a mean of 4.8 g per dL (48 g/L), and the patients were transfused with a mean of 7.8 +/- 2.3 units of group O red cells. One patient with hemolysis underwent exchange transfusion for acute renal failure. Patients with hemolysis required significantly more red cells postoperatively (15.0 vs. 6.9 units, p = 0.04) than did ABO-matched patients. None of the parameters examined (age, recipient or donor gender, secretor status, rejection, or donor isoagglutinin titers) were predictive of DDAb or hemolysis, although hemolysis occurred in three of four cases in which donor serum IgG anti-A titers were > or = 128, as opposed to one of four cases in which titers were < 128. Because recipients of ABO-unmatched livers are at high risk for transiently developing DDAb and hemolysis with associated morbidity, the prophylactic use of donor-type red cells for surgery and after operation is justified.

ABO Blood-Group System↗
PubMedDate not supplied

Dual-phase spiral CT angiography with volumetric 3D rendering for preoperative liver transplant evaluation: preliminary observations.

PURPOSE: The goal of our study was to determine whether dual-phase spiral CT angiography with 3D volume rendering could be used for preoperative evaluation and patient selection for orthotopic liver transplantation candidates. METHOD: Fifty consecutive potential candidates for liver transplantation were evaluated with dual-phase spiral CT with 3D volume rendering. Intravenous contrast medium was administered as bolus peripheral injection at 3 ml/s. The protocol consisted of a contrast-enhanced dual-phase spiral CT (arterial phase acquisition at 30 s after initiation of contrast medium injection followed by portal venous phase beginning at 60 s) with scan parameters of 0.75 s gantry rotation speed, 3 mm collimation, 5 to 6 mm/s table speed, and reconstruction at 1 mm intervals for arterial-phase images and 3 mm collimation for portal venous-phase studies (Siemens Plus 4 scanner; Siemens Medical Systems, Iselin, NJ, U.S.A.). All scan information was sent to a free-standing workstation (Silicon Graphics Onyx or Infinite Reality, Mountain View, CA, U.S.A.) for interactive real-time 3D volume rendering using a customized version of the Volren volume renderer (Silicon Graphics; Advanced Imaging Laboratory, Johns Hopkins Medical Institutions, Baltimore, MD, U.S.A.). The arterial phase was used to create vascular maps of the celiac axis including the origin(s) of the hepatic artery and origin of the superior mesenteric artery. The portal phase was used to define portal venous patency as well as the hepatic venous anatomy. All images were analyzed for vascular patency, shunting, or collateralization as well as the status of the underlying liver (i.e., liver size, cirrhosis, tumor, etc.). RESULTS: All 50 studies were successfully completed without complication. The 3D CT angiograms defined key arterial and venous structures including origin(s) of the hepatic artery, portal vein and/or superior mesenteric vein thrombosis, cavernous transformation of the portal vein, and/or other collateral vasculature. Ten patients (20%) demonstrated anomalous anatomy at the origin(s) of the hepatic artery. Portal vein thrombosis with cavernous transformation of the portal vein was shown in six patients, and there were three cases of partial venous thrombosis. Underlying liver tumors as well as parenchymal liver disease were well defined. Hepatic masses were found in five patients. Masses were pathologically proven as hepatocellular carcinoma (n = 1), giant cavernous hemangioma (n = 1), hepatic adenoma (n = 1), and focal nodular hyperplasia (n = 2). CONCLUSION: Preliminary results suggest that dual-phase spiral CT with CT angiography can provide a comprehensive preoperative liver transplant evaluation, supplying the necessary information for patient selection and surgical planning. As a single, minimally invasive examination, this should significantly impact patient care by minimizing procedures and avoiding potential complications.

Adolescent↗