Biomedical subjects

A F Shields

Publications and source records attributed to A F Shields.

43 records · Page 3Linked to original sources

PubMed1987

Magnetic resonance imaging of bone marrow in hairy cell leukemia: correlation with clinical response to alpha-interferon.

Five patients with progressive hairy cell leukemia were treated with recombinant alpha 2-interferon and examined prospectively at 3-month intervals using serial bone marrow biopsies and magnetic resonance (MR) imaging. Pretreatment iliac crest marrow biopsies demonstrated hairy cell infiltration involving 30-90% of marrow cellularity. Concurrent pretreatment coronal images of the proximal femurs and pelvis using MR revealed extensive marrow involvement that varied in distribution from patchy to diffuse. At 6 months, all patients had responded to alpha 2-interferon with improvement in peripheral blood counts and decrease in lymphoid infiltration on marrow biopsy to 15-40%. Six-month follow-up MR scans demonstrated decreasing marrow leukemia infiltration and increasing marrow fat. MR bone marrow imaging appears useful in the initial diagnosis of hairy cell leukemia, for monitoring the response to treatment, and possibly for predicting relapse.

Bone Marrow↗

PubMed1986

Magnetic resonance imaging of the bone marrow in patients with leukemia, aplastic anemia, and lymphoma.

Magnetic resonance imaging (MRI) of the bone marrow was performed in 29 patients with leukemia, aplastic anemia, or lymphoma who were scheduled for bone marrow transplantation, and in 12 normals. T1-weighted coronal images (TR600/TE40) of the pelvis and proximal femurs demonstrated marrow pathology in adult patients. A simple MR grading system was developed to classify patterns of marrow involvement, and MR grading of cellularity was correlated with marrow histology. Normal marrow produced a relatively high signal intensity reflecting the predominance of short T1 fat in the marrow space. MRI of pretransplant patients with chronic myelogenous leukemia and acute leukemia in relapse demonstrated a markedly decreased marrow signal, consistent with the replacement of marrow fat by longer T1 neoplastic tissues. Aplastic anemia could not be differentiated from normal with the pulse sequences employed. Marrow involvement by Hodgkin's lymphoma was detected as diffuse marrow infiltration with superimposed focal areas of even lower signal intensity, reflecting the nodular nature of Hodgkin's. These results indicate that infiltrative marrow disorders can be sensitively detected by MRI.

Adolescent↗

PubMed1986

Magnetic resonance imaging of bone marrow disorders.

The sensitivity of MRI to marrow infiltration together with the ability to perform multiplanar imaging allows evaluation of the bone marrow in a manner that has never been feasible before. The clinical impact of this has yet to be fully realized. However, detection of focal marrow infiltration by MRI with concurrently normal conventional imaging studies has important clinical implications for staging and therapy. Proper staging of marrow-based neoplasms such as leukemia and lymphoma is fundamental to the determination of treatment and prognosis. MRI can be used to increase diagnostic certainty when a question exists concerning primary or metastatic marrow disease when other imaging studies are inconclusive. Chemical shift imaging may further improve the sensitivity and clinical utility of magnetic resonance imaging in patients with hematologic disorders involving the bone marrow.

Adult↗

PubMed1985

Adenovirus infections in patients undergoing bone-marrow transplantation.

Viral infection is commonly observed after bone-marrow transplantation. We isolated adenovirus from 51 of 1051 patients undergoing marrow transplantation between 1976 and 1982. Of the 46 isolates available for typing, 13 (27.7 per cent) were of the closely related species 11, 34, or 35 (subgenus B). All 13 of the patients with these species had positive urine cultures. The species have previously been associated with the acquired immunodeficiency syndrome or with renal transplantation but are not commonly found in community surveys. Invasive infection was confirmed by biopsy or autopsy in 10 of 51 patients. Seven of the 10 had virus isolated from lung, and 4 died from pneumonia attributed to adenovirus. Two of the five patients with renal isolates had evidence of virally induced renal impairment, and both patients with liver isolates had adenovirus hepatitis. There was no common source that accounted for these adenovirus infections, and the most likely source of infection appeared to be endogenous viral reactivation. The only identifiable risk factor for the development of infection and for severe disease was the presence of moderate to severe graft versus host disease.

Adenoviridae Infections↗

PubMed1985

Comparison of neutralization and DNA restriction enzyme methods for typing clinical isolates of human adenovirus.

Sixty-five adenovirus isolates collected over a 3.5-year period were typed by both standard microneutralization techniques and restriction endonuclease digestion of viral DNA. Of the 65 isolates, 47 (72.3%) representing six adenovirus types could be typed by microneutralization. Eighteen isolates demonstrated partial neutralization with standard antisera to two or more adenovirus serotypes and thus could not be definitively typed. DNA analysis permitted typing of 64 of the 65 isolates (98.5%) (including four isolates which contained mixtures of two adenovirus types), and 12 different types were identified. Neutralization and DNA typing disagreed for five isolates, and in each case, digestion with multiple restriction endonucleases and DNA hybridization studies were consistent with the type assigned by DNA analysis. In addition, the DNA analysis method allowed the identification of genomic variants (genome types) of five adenovirus types. We conclude that typing clinical isolates of adenovirus by restriction endonuclease digestion of viral DNA can be done rapidly, provides additional epidemiological and typing information, and provides fewer ambiguous results than does typing by neutralization.

Adenoviruses, Human↗

PubMed1984

Short-term thymidine uptake in normal and neoplastic tissues: studies for PET.

Uptake of H-3 thymidine was studied in mice, both normal and with spontaneous lymphoma, and in the organs and tumors of dogs with spontaneous tumors. Uptake was compared with relative blood flow as measured by the distribution of C-14 iodoantipyrine. Initial distribution of thymidine in normal mice measured 20 sec after injection, correlated with the relative perfusion measurements; however, all measurements of thymidine uptake made between 1 and 60 min after injection showed no correlation with perfusion. This indicates that the distribution more than 1 min after injection is primarily dependent on subsequent redistribution and/or metabolism of thymidine. A time-course study demonstrated that normal mouse organs with high rates of proliferation retained all the labeled thymidine initially taken up. Organs with low rates of proliferation lost their label in a nearly exponential washout. These studies provide further evidence of the feasibility of using C-11 thymidine for positron emission tomography (PET).

Animals↗

PubMedDate not supplied

Characterizing tumors using metabolic imaging: PET imaging of cellular proliferation and steroid receptors.

Treatment decisions in oncology are increasingly guided by information on the biologic characteristics of tumors. Currently, patient-specific information on tumor biology is obtained from the analysis of biopsy material. Positron emission tomography (PET) provides quantitative estimates of regional biochemistry and receptor status and can overcome the sampling error and difficulty in performing serial studies inherent with biopsy. Imaging using the glucose metabolism tracer, 2 -deoxy-2- fluoro-D-glucose (FDG), has demonstrated PET's ability to guide therapy in clinical oncology. In this review, we highlight PET approaches to imaging two other aspects of tumor biology: cellular proliferation and tumor steroid receptors. We review the biochemical and biologic processes underlying the imaging, positron-emitting radiopharmaceuticals that have been developed, quantitative image-analysis considerations, and clinical studies to date. This provides a basis for evaluating future developments in these promising applications of PET metabolic imaging.

Cell Division↗