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Biomedical subjects

B Bowen

Publications and source records attributed to B Bowen.

47 records · Page 3Linked to original sources
PubMed1990

Localization of an acetylcholine receptor intron to the nuclear membrane.

The first intron of the RNA for the acetylcholine receptor (AChR) alpha subunit shows a ringlike distribution around nuclei in multinucleated myotubes by in situ hybridization. This pattern is not observed for an actin intron or U1 RNA. Quantitation of the intron sequences reveals large variations in the amount of both the AChR and actin introns between nuclei within the same myotube, although all nuclei express equivalent amounts of U1 RNA. This differential RNA expression indicates that nuclei can individually control expression of messenger RNAs. The restricted distribution of the AChR intron RNA suggests a previously unknown step in RNA processing.

Actins↗
PubMed1990

Quantitation of chloramphenicol acetyl transferase in transgenic tobacco plants by ELISA and correlation with gene copy number.

A monoclonal antibody to chloramphenicol acetyl transferase (CAT) was used in an indirect competitive enzyme immunoassay (ELISA) for the quantitation of CAT in leaf extracts of eighteen transgenic tobacco plants containing the CAT gene fused to the cauliflower mosaic virus 35S promoter. The ELISA could be used to quantify CAT when present in extracts at 20 ng/ml. Enzymatic activity and electrophoretic mobility of CAT in these extracts was not different from CAT from Escherichia coli. Concentrations of CAT in these transgenic plants ranged from 79 to 732 ng CAT/mg protein. The average coefficient of variation among three replicate samples was 15%. All plants were sampled on two separate occasions. The CAT concentrations often varied between the two sampling dates. We determined the CAT gene copy number and the number of independently segregating loci in each plant by Southern blot analysis and progeny testing. We found no significant differences in CAT expression among all ten plants with a single CAT gene. We also found a significant correlation between CAT gene copy number and the level of CAT expressed in each plant, although plants with one gene copy sometimes had more CAT than plants with more than one gene copy. In this population, therefore, gene copy number contributed more to the variation in CAT expression than did position effects.

Chloramphenicol O-Acetyltransferase↗
PubMed1989

Sensitivity and specificity of positron emission tomography and magnetic resonance imaging studies in Alzheimer's disease and multi-infarct dementia.

Positron emission tomographic (PET) scans using [18F]-fluorodeoxyglucose and magnetic resonance imaging (MRI) scans were quantitatively analyzed for metabolic and structural abnormalities in normal subjects and patients classified as having Alzheimer's disease (AD), mixed dementia and multi-infarct dementia (MID) according to Hachinski ischemic scores. MRI-detected abnormalities in the periventricular white matter and in subcortical locations increased in incidence with age in normals and increased markedly in AD and especially in MID. Upper limits for the severity of these white matter lesions could be defined only for normal young and elderly subjects, but not for AD, mixed or MID patients. PET scan abnormalities occurred in about 90% of demented patients and in 54% of elderly and 34% of young normals. There was no characteristic pattern of abnormality that distinguished MID from AD patients. It is concluded that PET and MRI studies in demented patients are useful ancillary tests especially in evaluating the mild, questionably demented subject and for assessing the functional impact of structural disease.

Aged↗
PubMed1987

Gastrointestinal teratomas: CT and US appearance with pathologic correlation.

Gastrointestinal teratomas are uncommon, benign neoplasms that occur primarily in children. A retrospective review of five cases (two gastric, one pancreatic, one mesenteric, and one in the lesser omentum) is presented with emphasis on the computed tomographic and ultrasonographic appearances. Principal findings are a well-defined mass with separate cystic and solid components of varying proportions, discrete areas with densities similar to that of fat, or coarse, globular calcifications within the solid component. Recognition of these findings may allow the radiologist to make a correct preoperative diagnosis of teratoma.

Child, Preschool↗
PubMed1986

Indirect immunofluorescence of oral lichen planus.

Sections of lesional tissue from 6 patients who exhibited only oral lesions of lichen planus (LP) were incubated with autologous serum and studied immunopathologically for the presence of lichen planus specific antigen (LPSA). None of the specimens was positive for LPSA. Serum from the oral LP patients was subsequently incubated with allogeneic cutaneous LP lesional tissue sections, which resulted in the demonstration of LPSA in 2 of the 4 sera examined. These results suggest an immunologic relationship between cutaneous LP and at least some cases of oral LP.

Adult↗
PubMed1981

Stabilization of 99mTc-pyrophosphate injection with gentisic acid.

The in vitro oxidation of 99mTc-labelled bone-scanning agents with the release of free sodium 99mTc-pertechnetate results in poor skeletal images. Gentisic acid (2,5-dihydroxy-benzoic acid), which has been used as an antioxidant to stabilize HEDP and HMDP kits, has now been shown to be an effective stabilizer for 99mTc-Pyrophosphate Injection and doses not compete for 99mTc-label.

Animals↗
PubMed1980

The detection of DNA-binding proteins by protein blotting.

A method, called "protein blotting," for the detection of DNA-binding proteins is described. Proteins are separated on an SDA-polyacrylamide gel. The gel is sandwiched between 2 nitrocellulose filters and the proteins allowed to diffuse out of the gel and onto the filters. The proteins are tightly bound to each filter, producing a replica of the original gel pattern. The replica is used to detect DNA-binding proteins, RNA-binding proteins or histone-binding proteins by incubation of the filter with [32P]DNA, [125I]RNA, or [125I] histone. Evidence is also presented that specific protein-DNA interactions may be detected by this technique; under appropriate conditions, the lac repressor binds only to DNA containing the lac operator. Strategies for the detection of specific protein-DNA interactions are discussed.

Carrier Proteins↗