Digital subtraction angiography systems: assessing performance with phantoms

A solid, acrylic phantom was developed to assess the iodine perceptibility of three digital subtraction angiography (DSA) systems, including one using a recursive filter technique. Three phantoms, designed to mimic flow of iodinated boluses through blood vessels, were used. Each contained four triangular boluses of different widths and of a specific iodine concentration. Motion, required to test recursively filtered DSA systems, was simulated by placing the phantoms on a motorized cart. The phantoms were also used to test flow curve generation in applicable systems. Intersystem differences in perceptibility were attributed to differences in system noise, system resolution, and dynamic range. Flow curves produced with the phantoms were similar to those obtained in patient studies.     

Tomographic digital subtraction angiography: initial clinical studies using tomosynthesis. Work in progress

We have developed a method for acquiring multiple tomographic subtraction images using a rapid, repetitive, circular tomographic motion. The method combines the principles of digital subtraction angiography (DSA) and electronic tomosynthesis. Fifteen patients were examined with the technique using single intravenous bolus injections of contrast material. The image sequence obtained during each injection was first processed with a nontomographic mask subtraction, and the result was then compared with the tomographic DSA scans synthesized from the same sequence. The effective section thickness was approximately 0.5 cm, with each section being 0.5-1.0 cm apart. Twelve of the intravenous DSA scans provided the necessary diagnostic or clinically useful information. Two of the three nondiagnostic scans were caused by avoidable technical reasons. In eight cases, the tomographic DSA scans were superior in quality to the nontomographic scans, exhibited significantly less artifact from patient motion and overlying bowel gas, and were effective in separating overlapping vessels. Tomosynthesis permits multiple electronic imaging of the area of interest without reinjection of contrast material and appears to be more informative than nontomographic intravenous DSA imaging.     

Long-range mapping of the Philadelphia chromosome by pulsed-field gel electrophoresis

The Philadelphia chromosome (Ph1) of chronic myelogenous leukemia (CML) contains sequences from chromosome 9, including the ABL protooncogene, that have been translocated to the breakpoint cluster region (bcr) of chromosome 22, giving rise to a bcr-ABL fusion gene, whose product has been implicated in the genesis of CML. Although chromosome 22 translocation breakpoints in CML virtually always occur within the 5.8- kilobase (kb) bcr, chromosome 9 breakpoints have been identified within the known limits of ABL in only a few instances. For a better understanding of the variability of the breakpoints on chromosome 9, we studied the CML cell line BV173. Using pulsed-field gel electrophoresis (PFGE), large-scale maps of the t(9;22) junctions were constructed. The chromosome 9 breakpoint was shown to have occurred within an ABL intron, 160 kb upstream of the v-abl homologous sequences, but still 35 kb downstream of the 5'-most ABL exon. bcr-ABL and ABL-bcr fusion genes were demonstrated on the Ph1 and the 9q+ chromosomes, respectively; both of these genes are expressed. These results suggest that the 9;22 translocation breakpoints in CML consistently occur within the limits of the large ABL gene. RNA splicing, sometimes of very large regions, appears to compensate for the variability in breakpoint location. These studies show that PFGE is a powerful new tool for the analysis of chromosomal translocations in human malignancies.     

Small lymphocytic lymphoma: a clinicopathologic analysis of 268 cases

We analyzed specimens from 268 patients with small lymphocytic lymphoma (SL) to identify prognostic factors significant for survival. These patients were staged and treated according to the protocols of the Cancer and Leukemia Group B, Eastern Cooperative Oncology Group, Southeastern Cancer Study Group, and the Southwest Oncology Group. Univariate analysis showed that a large-cell grade greater than I, WBC greater than 10,000/microL, hemoglobin (Hgb) less than 11 g/dL, age greater than or equal to 55 years, and failure to respond to treatment were all poor prognostic factors. Multivariate analysis showed that large-cell grade, age, degree of capsular invasion, and symptom type were independently associated with survival. Separate analyses of cases with and without leukocytosis indicated differences in survival. In patients without leukocytosis, age, presence or absence of anemia, and treatment response were significant prognostic variables; in patients with leukocytosis, large-cell grade, presence or absence of anemia, symptom type, and treatment response were significantly related to survival. Multivariate analysis showed that age was the only significant independent prognostic variable in patients without leukocytosis; in patients with leukocytosis, symptom type, large-cell grade, and bone marrow involvement were independently associated with survival. We conclude that several parameters, both clinical and pathologic, should be assessed at the initial diagnosis of SL to predict prognosis better.     

Dental health requirements for psychiatric patients

Background: This study was conducted to assess the dental treatment requirements of psychiatric patients in comparison with the non psychiatric patients admitted in the hospital.     

Acute intestinal pseudo-obstruction

Opinion statement  

Nuclear translocation of beta-catenin in hereditary and carcinogen- induced intestinal adenomas

The physical interaction between beta-catenin and the adenomatous polyposis coli (APC) gene, and the ability of APC to regulate cytoplasmic levels of beta-catenin suggest a role for beta-catenin in colorectal carcinogenesis. In this study, we found that beta-catenin immunoreactivity was detected exclusively in the cell membrane and cytoplasm of morphologically normal intestinal epithelial cells with predominant distribution in the differentiated nonproliferative cell population. In contrast, beta-catenin was localized predominantly in the nucleus of adenomas from Min/+ mice and transgenic mice expressing a mutant truncated form of the APC gene (Apc(delta716) mice). Beta- catenin was expressed predominantly at the cell membrane and cytoplasm of the nontransformed rat intestinal epithelial (RIE-1) cells in culture, whereas predominantly nuclear localization of beta-catenin was observed in the human colon cancer cell line SW480. In the azoxymethane (AOM) treated rats, overexpression and nuclear localization of beta- catenin was observed in all adenomas. Previous studies have indicated the incidence of APC mutations amongst AOM-induced tumors to be 15% or less. These results demonstrate that nuclear localization of beta- catenin is a common event in colorectal tumorigenesis.      

Identification of tamoxifen-DNA adducts formed by 4-hydroxytamoxifen quinone methide

Tamoxifen is a liver carcinogen in rats and has been shown to increase the risk of endometrial cancer in women. Recent reports of DNA adducts in leucocyte and endometrial samples from women treated with tamoxifen indicate that it may be genotoxic to humans. One of the proposed pathways for the metabolic activation of tamoxifen involves oxidation to 4-hydroxytamoxifen, which may be further oxidized to an electrophilic quinone methide. In the present study we show that 4- hydroxytamoxifen quinone methide reacts with DNA to form covalent adducts. The major products, which result from 1,8-addition of the exocyclic nitrogen of deoxyguanosine to the conjugated system of 4- hydroxytamoxifen quinone methide, are characterized as (E)- and (Z)- alpha-(deoxyguanosin-N2-yl)-4-hydroxytamoxifen.