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S G Moore

Publications and source records attributed to S G Moore.

26 records · Page 2Linked to original sources
PubMed1990

Early and late bone-marrow changes after irradiation: MR evaluation.

Knowledge of the chronologic evolution of bone-marrow changes during and after radiation therapy is essential in differentiating normal postradiation changes from other marrow abnormalities. The appearance of the lumbar vertebral bone marrow was studied on 55 serial spin-echo and short-T1 inversion-recovery (STIR) MR images obtained in 14 patients receiving radiation therapy for Hodgkin disease, seminoma, or prostate carcinoma. Images were obtained before, at weekly intervals during, and at various monthly intervals up to 14 months after a 3- to 6-week course of fractionated paravertebral lymph-node irradiation of 1500-5000 rad (15-50 Gy). During the first 2 weeks of therapy, there was no definite change in the appearance of the marrow on spin-echo images; however, there was an increase in signal intensity on the STIR images, apparently reflecting early marrow edema and necrosis. Between weeks 3 and 6, the marrow showed an increasingly heterogenous signal and prominence of the signal from central marrow fat, shown best on T1-weighted images. Late marrow patterns (6 weeks to 14 months after therapy) varied and consisted of either homogenous fatty replacement or a band pattern of peripheral intermediate signal intensity, possibly representing hematopoietic marrow surrounding the central marrow fat. No focal marrow lesions or soft-tissue edema were identified during the course of radiation therapy; their presence should raise the possibility of the presence of a pathologic process other than radiation change. These data suggest that MR can detect radiation-induced marrow changes as early as 2 weeks after starting therapy, and that there are at least two distinct types of late marrow MR patterns.

Adolescent↗
PubMed1990

The efficacy and clinical impact of brain imaging in neurologically symptomatic AIDS patients: a prospective CT/MRI study.

The relative efficacies of cranial magnetic resonance imaging (MRI) and computed tomography (CT) brain scans for the detection of intracranial pathology in patients with the acquired immune deficiency syndrome (AIDS) were evaluated prospectively. Fifty homosexual or bisexual men with AIDS and neurologic symptoms were evaluated using both modalities. In 24 patients, MR images and CT scans provided the same diagnostic information (within normal limits in 16, cerebral atrophy only in 6, and similar lesions in 2 patients). In only one instance did CT show the presence of a lesion not seen on MRI. In the 25 remaining patients, MRI was the more sensitive modality. MRI also reflected more consistently the histopathologically documented extent and distribution of central nervous system disease. The greater sensitivity of MRI suggested significant alterations in the diagnostic evaluation and therapeutic management of 20 patients. Thus, MRI was as good or better than CT for the detection of intracranial pathology in 49 of 50 neurologically symptomatic AIDS patients and significantly affected the diagnosis and treatment of 40% of these patients. Although MRI does not appear to be more specific than other modalities in the differentiation of human immunodeficiency virus (HIV)-related neurologic diseases, its greater sensitivity suggests that MRI may be the best neuroimaging procedure for the initial radiologic evaluation of AIDS patients with neurologic illness.

Acquired Immunodeficiency Syndrome↗
PubMed1987

MR imaging of intracranial tuberous sclerosis.

The role of MR in evaluating tuberous sclerosis is reviewed in 15 patients. These studies were compared with CT scans, which were available in 14 patients. Four characteristic findings were noted on the MR images obtained. Subependymal nodules projecting into the lateral ventricles were seen in 12 of 15 patients on T1-weighted images. This was the most specific finding. Distortion of the normal cortical architecture was seen in 10 of 11 patients in whom T1-weighted images were obtained using a 256 X 256 matrix. These foci corresponded to multiple cortical areas of increased signal on T2-weighted images. Dilated ventricles were seen in five patients. In one patient, a known astrocytoma showed increased signal on the T2-weighted images, allowing differentiation from a benign subependymal nodule. MR depicted the cortical hamartomas more completely than did CT. The MR scans were abnormal in all cases, and a diagnosis could be confidently made in all 11 cases scanned using a 256 X 256 matrix. Our preliminary experience suggests that MR will at least equal and probably exceed CT, both for sensitivity and specificity, given the use of a 256 X 256 matrix.

Adolescent↗
PubMed1986

Micro-BIA, a colorimetric microtiter assay of lambda prophage induction.

Escherichia coli that are lysogenic for a lambda-lacZ fusion phage produce beta-galactosidase, product of the lacZ gene, upon induction of the prophage by DNA-damaging agents. The miniaturization of a quantitative, colorimetric beta-galactosidase (prophage) induction assay (BIA) is presented. Induction assays are performed in microtiter wells with the aid of multichannel pipetting devices. Results are shown with screening strain BR513 (uvrB delta envA) and a strain, BR339 (uvrB delta lexA3ind-) which exhibits enhanced induction. A method developed for strain BR339 utilizes bacteria stored frozen in log phase, permeabilized in vitro, and used immediately; with this method, 2 consecutive assays may be completed in 1 working day. Mutagens utilized for the model studies included 4NQO, ENNG, daunorubicin, bleomycin, acetoxy-AAF, B[a]P, DMBA, and DEN (the last three in the presence of liver S9). Induced levels of beta-galactosidase were monitored using a vertical light path photometer that measured color absorbance in each microtiter well. Alternatively, color intensity could be determined by using a color chart prepared for this assay. These values were then plotted to generate dose-response curves. Considerable savings in labor and materials are achieved with the method described, one which may be used as a screen for DNA-damaging chemicals. Automated equipment and computers may be used to advantage with this assay, but they are not required.

Animals↗
PubMed1986

Bone marrow in children with acute lymphocytic leukemia: MR relaxation times.

Magnetic resonance imaging of the lumbar spine was performed in 17 children with acute lymphocytic leukemia (ALL): eight with newly diagnosed ALL, four with ALL in relapse, and five with ALL in remission. Eleven age-matched children were also imaged as controls. The T1 and T2 relaxation times of the bone marrow in the lumbar spine were calculated for all the children. The T1 relaxation times of the bone marrow were as follows (mean +/- standard deviation): newly diagnosed ALL, 968 msec +/- 68; ALL in relapse, 765 msec +/- 19; ALL in remission, 404 msec +/- 135; and age-matched controls, 441 msec +/- 82. T1 relaxation time was statistically significant in differentiating children with newly diagnosed ALL from normal children and from children with ALL in remission. In addition, T1 may be useful in differentiating children with ALL in relapse from children with ALL in remission and from healthy children. T2 was not significantly different among the four groups.

Adolescent↗
PubMed1985

Magnetic resonance imaging of the hip.

Magnetic resonance imaging of the musculoskeletal system in general and the hip in particular offers many exciting opportunities for innovative and revolutionary diagnostic avenues, the full potential of which awaits further investigative and clinical experience.

Bone Marrow Diseases↗
PubMed1984

Genetic and biochemical factors affecting the induction of bacteriophage lambda by N-nitroso compounds.

As part of our effort to validate a biochemical (prophage) induction assay (BIA) as a screening test for carcinogens, we have tested more than 100 N-nitroso compounds. An enzyme, beta-galactosidase, is induced as an indirect consequence of DNA damage to the host, as part of the 'SOS' response. Besides the obvious practical importance of detecting this class of carcinogen, there is the question of the mechanism by which these compounds work. Mutagenesis by one compound, N-methyl-N'-nitro-N-nitrosoguanidine, is known to proceed by both SOS (recA)-dependent and SOS-independent pathways. Mispairing due to O6 alkylation of guanine is thought to be responsible for the SOS-independent pathway; however, there has been little consideration of recA-dependent functions, of which phage induction is one. Although nitrosamides could be detected as phage inducers in our assay, N-nitrosamines in the presence of rat liver 9 000 X g supernatant usually gave no response. We found that the use of several mutant strains, particularly a lexA mutant, in combination with hamster liver 9 000 X g supernatant, allowed us to detect most N-nitrosamines reasonably well, in either a spot test or a quantitative tube assay. Induction in a lexA strain was most unexpected, since this mutation usually diminishes the expression of SOS functions induced by ultra-violet light. Because the genetic and biochemical conditions that favour phage induction are different from those that favour mutagenesis, it seems likely that the lesions in DNA leading to the two biological end-points are different.

Bacteriophage lambda↗