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Biomedical subjects

B Lyons

Publications and source records attributed to B Lyons.

At least 73 records · Page 4Linked to original sources
PubMed1982

A new formulation of Tc-99m minimicroaggregated albumin for marrow imaging: comparison with other colloids, In-111 and Fe-59.

The biodistributions of five Tc-99m colloids were compared with the 24-hr distributions of Fe-59 and In-111 in dogs by direct radioassay 1 hr after intravenous injection. One formulation of Tc-99m minmicroaggregated albumin (particle size 30-100 mn), produced the highest marrow concentration, approximately six times that of Tc-99m sulfur colloid, with similar blood, and liver concentrations and a lower splenic uptake. Nevertheless, the best colloid marrow uptake was lower than the 24-hr value for In-11 and much lower than that for Fe-59. The marrow concentration of minimicroaggregated albumin was also higher than that of sulfur colloid in rats at 30 min after injection. The principal disadvantage of Tc-99m antimony sulfide colloid was its slow blood clearance. Clinical evaluation of Tc-99m minimicroaggregated albumin for marrow imaging appears warranted, although its hepatic activity will obscure overlying and immediately adjacent marrow.

Animals↗
PubMed1981

Experimental study of high-resolution ultrasound imaging of hemorrhage, bone fragments, and foreign bodies in head trauma.

The accuracy of high-resolution ultrasound scans in detecting foreign bodies and hemorrhage within the brain was evaluated by comparison with computerized tomography (CT) scans and gross pathology. The test lesions were blood and foreign bodies consisting of bone, wood, and metal placed in the brain of an experimental animal. High-resolution ultrasound scans (10 MHz) performed in coronal and sagittal planes accurately delineated the position and spatial orientation of these foreign bodies and hemorrhage. Both hemorrhage and foreign bodies were echogenic compared to normal, hypoechoic brain parenchyma. Metal fragments had a highly characteristic echo pattern caused by sound reverberation within the object. Acute intracerebral hemorrhage produced an ultrasound image consisting of sharply circumscribed homogeneous echoes. The sonographic shape of intracerebral hemorrhage correlated closely with the area of increased density seen on the CT scan. High-resolution ultrasonography accurately delineated experimentally produced components of head trauma and may prove useful as an intraoperative imaging technique to facilitate surgery in head-injured patients.

Animals↗
PubMed1966

The nursing aide.

Explore the source record for details and available documents.

Australia↗
PubMedDate not supplied

Experimental drug-induced changes in renal function and biodistribution of 99mTc-MDP.

Increased renal uptake of 99mTc methylene diphosphonate (MDP) was observed irregularly in rats after methotrexate, vincristine or gentamicin, administered separately. Cisplatin regularly induced a dose-related increased MDP uptake which correlated with the degree of tubular damage histologically. The augmented MDP renal uptake was not consistently accompanied by a decreased clearance of simultaneously injected I-131 Hippuran, particularly at lower drug dose levels. This observation agreed with previous evidence that the mechanisms of tubular transport of diphosphonates and organic acids like Hippuran are different. At higher dose levels, the augmented MDP uptake was accompanied by increased renal calcium, hypophosphatemia, elevated serum urea nitrogen and creatinine, and only occasional, mild hypercalcemia. The magnitude of the increased renal uptake of MDP observed could not be explained by alterations in iron metabolism or by dehydration. Drug-induced renal retention of MDP by a factor of 2 or more above normal appears to be a useful indicator of tubular damage when other parameters of renal function are sometimes normal.

Animals↗
PubMedDate not supplied

Comparison of 99mTc phosphate and diphosphonate complexes in experimental renal infarcts.

The 3-hour biodistribution of 99mTc complexes of five diphosphonates (HMDP, NMMDP, DMAD, DPD, and APD), imidodiphosphonate (IDP), and pyrophosphate (PYP) was compared in rats with segmental renal infarction induced by a 1-hour occlusion of a renal artery branch. 95mTc labeled MDP was a reference substance in all animals. Three agents (APD, HMDP and IDP) had a higher infarct/normal kidney concentration ratio than MDP, the latter two by virtue of a lower content in normal kidney. HMDP, DPD, and IDP had very high liver concentrations. DPD showed relatively high concentrations in soft tissues and blood. The blood and kidney levels of PYP were higher than those of MDP but the infarct/normal kidney ratios were similar. None of the agents had a higher uptake in bone than MDP: four had a significantly lower uptake. The increased concentration of 99mTc MDP in the infarcts was readily seen in camera images one day after renal artery occlusion, but not at three or seven days. Increased diphosphonate uptake was accompanied by an influx of calcium in both cortex and medulla. The accumulation of diphosphonate in areas of infarction was not modified by infusions of verapamil or Captopril.

Animals↗
PubMedDate not supplied

Changes in renal uptake of Tc-99m methylene diphosphonate (MDP) in stone-forming rats.

A pyridoxine (vitamin B6)-deficient diet in rats was used as a model of early renal lithiasis to find out if "stone-formers" could be identified from control animals by differences in the biodistribution of Tc-99m MDP. The mean renal uptake of this agent at 3 hours was about 70% higher in test animals than in controls, but there was considerable overlap between the upper limits of the normal range and lower values in "stone-formers." If these results were valid for humans, the metabolic abnormality in males with early stone-forming disease could not be identified with certainty by in vivo measurements of Tc-99m MDP renal uptake alone. However, the skeletal uptake of MDP in the "stone-forming" animals was depressed by 28 to 35%, compared with control rats. Consequently, the renal to skeletal MDP concentration ratio was invariably elevated in "stone-formers" beyond the 95 percentile normal range. Unexpectedly, 76% of the pyridoxine-deficient animals had a higher accumulation of MDP in the myocardium than the upper limit of the normal range. The pyridoxine-deficient diet induced no remarkable early changes in the biodistribution or renal clearance of I-131 Hippuran.

Animals↗
PubMedDate not supplied

Insurance matters for low-income adults: results from a five-state survey.

Using survey data from 2,000 low-income adult respondents in each of five states, this DataWatch assesses how uninsured, low-income adults differ from low-income adults who have public or private insurance and how Medicaid expansions have affected insurance coverage patterns across states with different eligibility policies. Findings show that the proportion of low-income uninsured adults is two to three times higher in states that have not expanded Medicaid eligibility beyond relatively low welfare levels. Compared with persons who have either Medicaid or private insurance, uninsured persons report more difficulties getting needed care, are less likely to have a regular provider, and rate the care they do receive as lower quality.

Adult↗
PubMedDate not supplied

Managed care and low-income populations: recent state experiences.

This DataWatch examines the relationship between managed care enrollment and access to care for low-income adults with Medicaid and compares their experience with that of low-income, privately insured managed care enrollees. Medicaid managed care enrollees are more likely than low-income, privately insured managed care enrollees to be poorer, have health problems, and experience access problems. Compared with low-income populations in fee-for-service care, managed care enrollees, whether in Medicaid or privately insured, are not appreciably different in having a usual source of care, having a regular provider, or emergency room use but report more problems in obtaining care and are more likely to be dissatisfied with their health plans.

Adult↗