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Biomedical subjects

E Hoffman

Publications and source records attributed to E Hoffman.

At least 91 records · Page 5Linked to original sources
PubMed1983

Characterization of a new human diploid cell line--IMR-91.

A human diploid fibroblast cell line has been established from the lung tissue of a male fetus. This has been characterized and frozen away in large quantity. A smaller quantity of fibroblastlike cells from skin has also been established, partially characterized, and placed in frozen storage from the same fetus. This project is in support of the National Institute on Aging research in general cell biology. The present lines designated IMR-91 lung and IMR-91 skin complement the previous human diploid fibroblast culture (IMR-90) established from a female fetus. The lack of random inactivation of one of the two X chromosomes in the present male line reduces the genetic heterogeneity inherent in the female line.

Cell Division↗
PubMed1983

Action of sotalol on potential reentrant pathways and ventricular tachyarrhythmias in conscious dogs in the late postmyocardial infarction phase.

Sotalol is a beta-adrenergic blocker that also prolongs action potential duration and myocardial refractoriness over the short term (class III effect). Its short-term antiarrhythmic effects were compared with those of metoprolol, which has neither short-term class III nor membrane-stabilizing action, on reentrant ventricular arrhythmias produced by programmed stimulation in 17 conscious dogs 3 to 8 days after myocardial infarction. Ventricular arrhythmias were prevented or significantly slowed by sotalol in 11 of 19 studies (58%) compared with in one of 14 (7%) studies with metoprolol. Sotalol prolonged refractoriness in the infarct zone, measured from an implanted "composite" electrode, by 41 +/- 45% (mean +/- SD, p less than .01), which was significantly greater than the increases it produced in effective refractory period of the normal ventricle (14.0 +/- 5.5%) or QT interval (12.5 +/- 7.8%). Metoprolol had no effect on infarct-zone refractoriness. Sotalol differentially increases refractoriness in potential reentry circuits in ischemic myocardium. Its antiarrhythmic effect in this model is not due to beta-blockade, and is presumably related to prolongation of action potential duration.

Action Potentials↗
PubMed1983

Measurements of regional tissue and blood-pool radiotracer concentrations from serial tomographic images of the heart.

Quantification of myocardial tissue kinetics from serial tomographic images is limited because of bidirectional cross-contamination of recorded counts between myocardium and blood for metabolic tracers with relative slow blood clearance. We have developed and validated a new deconvolution technique that permits calculation of spillover fractions derived from geometric measurements of the imaged cross section (wall thickness, chamber diameter) and the intrinsic resolution of the tomograph. Serial gated positron-emission computerized imaging (PCT) and a-v blood sampling across the heart were performed in five dogs for 45 min after i.v. C-11 palmitate (CPA) and in five dogs for 3 hr after i.v. F-18 deoxyglucose (FDG). Tracer concentrations in myocardial tissue and arterial blood were also measured in vitro. Uncorrected PCT tissue and blood concentrations correlated poorly with in vitro measurements. After correction for count crossover, the correlation for FDG in tissue was r = 0.99, for FDG in blood r = 0.97, and for CPA in blood r = 0.99. Deconvolution techniques applied to serial PCT images provide accurate noninvasive measurement of myocardial tracer concentrations and direct determination of the arterial input function required for measurements of myocardial metabolism.

Animals↗
PubMed1982

Performance of the rotating slant-hole collimator for the detection of myocardial perfusion abnormalities.

To determine the usefulness of the rotating slant-hole (RSH) collimator, a new imaging device for tomographic myocardial imaging, we evaluated its performance in phantom studies. Perfusion defects of variable size, location, and tracer concentration were simulated and imaging was performed with a conventional parallel-hole collimator and the RSH collimator. Planar and depth resolutions assessed with a line source compared favorably with those reported previously for the seven-pinhole collimator. The results also showed RSH tomography to be more sensitive than planar imaging in detecting simulated myocardial defects but indicated some limitations, especially the occurrence of artifactual defects that may reduce the specificity of the imaging device for the detection of perfusion abnormalities.

Coronary Disease↗
PubMed1981

REM sleep dreams and the activation-synthesis hypothesis.

The authors studied 104 dreams obtained from 14 subjects and quantified the formal aspects of the subjects' dream experiences by the following categories: movement in dreams, sensation, affect, dream bizarreness, and dream lucidity. Their results are compared with the predictions of the activation-synthesis hypothesis, which postulates that the characteristic formal aspects of dreams correspond to characteristic aspects of physiological activation during REM sleep. Although further experimental work is needed, the authors show that their results are consistent with and supportive of the activation-synthesis hypothesis.

Affect↗
PubMed1980

Regional myocardial blood flow, metabolism and function assessed noninvasively with positron emission tomography.

Positron emission computed tomography is a new technique of potential value for the noninvasive measurement of myocardial blood flow, mechanical function and, in particular, metabolism. The capability of this new study method is attributable to the technologic innovations of the imaging device and the availability of radioactive tracers that are specific for blood flow and metabolism. The device permits recording of cross-sectional images of the left ventricular myocardium that quantitatively reflect regional tracer tissue concentrations. Use of tracer kinetic models with this new technique permits measurements of regional glucose and fatty acid metabolism of the heart. Positron emission tomography is already an important new tool for investigative studies of cardiac physiology and pathophysiology; its clinical utility remains to be defined.

Ammonia↗
PubMed1980

Further observations on a 13qXp translocation associated with retinoblastoma.

In a patient with a 13qXp translocation and retinoblastoma the band associated with retinoblastoma (13q14) was clearly translocated intact to the X chromosome rather than being the breakpoint of the translocation. Genetic inactivation of the derivative X chromosome shown by late labeling and cell hybridization techniques in the predominance of cells indicated a functional monosomy for this segment as the most likely predisposing factor in producing retinoblastoma.

Chromosomes, Human, 13-15↗
PubMed1979

Interstitial deletion of chromosome 13 and associated congenital anomalies.

An interstitial deletion of chromosome 13 with breakpoints at 13q22 and 13q32 is presented. The clinical findings associated with this deletion are discussed in relation to the correlations of specific chromosomal bands with constellations of congenital defects as described by Niebuhr and Ottosen (1973), Niebuhr (1977). Lewandowski and Yunis (1975), and Noel et al. (1976).

Abnormalities, Multiple↗
PubMed1979

Retinoblastoma, chromosome 13, and in vitro cellular radiosensitivity.

Five diploid fibroblast strains from patients with deletions mapping in the long arm of chromosome 13 and three strains bearing partial trisomies of chromosome 13 were assayed for clonogenic survival following X-irradiation. Results of these experiments suggest the existence of a region on 13q14 which is related to increased sensitivity to cell killing in vitro by X-rays. This locus seems to be distinct from but close to the retinoblastoma locus, which has been associated with the same band.

Chromosome Deletion↗
PubMed1979

The [18F]fluorodeoxyglucose method for the measurement of local cerebral glucose utilization in man.

A method has been developed to measure local glucose consumption in the various structures of the brain in man with three-dimensional resolution. [18F]-2-deoxy-2-fluoro-D-glucose is used as a tracer for the exchange of glucose between plasma and brain and its phosphorylation by hexokinase in the tissue. A mathematical model and derived operational equation are used which enable local cerebral glucose consumption to be calculated in terms of the following measurable variables. An intravenous bolus of [18F]-2-deoxy-2-fluoro-D-glucose is given and the arterial specific activity monitored for a predetermined period of from 30 to 120 minutes. Starting at 30 minutes, the activity in a series of sections through the brain is determined with three-dimensional resolution by an emission tomographic scanner. The method was used to measure local cerebral glucose consumption in two normal volunteers. The values in gray matter structures range from 5.79 mg/100 g per minute in the cerebellar cortex to 10.27 in the visual cortex, whereas, in white matter structures, the values range from 3.64 mg/100 g per minute in the corpus callosum to 4.22 in the occipital lobe. Average values for gray matter, white matter, and whole brain metabolic rates, calculated as a weighted average based on the approximate volume of each structure, are 8.05, 3.80, and 5.90 mg/100 g per minute, respectively. The value of 5.9 mg/100 g per minute compares favorably with values previously reported.

Adult↗
PubMed1978

Policy and politics: the Child Abuse Prevention and Treatment Act.

Politics and policy frequently interact to affect substantially the final shape of legislation. In the case of the Child Abuse Prevention and Treatment Act, public hearings and the media focused attention on the problem of abused children, helping to create a climate favorable for action by the Congress. The shapers of the bill deliberately accepted an incremental approach, believing that adequate funding for a more comprehensive attack on child abuse was not forthcoming. This "something is better than nothing" strategy may well be appropriate at the present time for many children's programs.

Child↗