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Biomedical subjects

E M Smith

Publications and source records attributed to E M Smith.

At least 253 records · Page 14Linked to original sources
PubMed1977

Altered intracellular transport of exogenous DNA by murine mammary tumor cell lines.

The uptake of exogenous DNA by a series of murine mammary tumor cell lines was compared with DNA uptake by normal cells and other types of transformed cells. The mammary tumor cell lines all exhibited a decreased efficiency in the transport of DNase-resistant exogenous DNA into the nuclear fraction. None of the DNA facilitators tested were able to surmount this transport defect. Normal mouse mammary gland cells, mouse embryo cells, and normal kidney cells from various species efficiently transported exogenous DNA into the nucleus. Similarly, the transport defect was not exhibited by a series of transformed cell lines, including those of mouse origin and those transformed by C-type oncornaviruses. The only exception was a murine leukemia virus-producing mouse line that displayed decreased nuclear uptake of the DNA. The nature of the exogenous DNA was apparently not a factor, since identical results were obtained with simian virus 40 and mammalian cell DNA's. The inducing agents of the mammary tumor cells also did not appear to be a factor, since cell lines derived from tumors induced spontaneously or by viral, hormonal, or chemical carcinogens all behaved similarly.

Animals↗
PubMed1977

Development of a quantitative method for detecting enteroviruses in estuarine sediments.

Several investigators have reported on the detection of enteric viruses in marine sediments, but none determined the efficiency of their methods and only limited volumes of sediment were sampled. The purpose of this investigation was to develop a quantitative method for detecting enteroviruses in marine sediments so that their relative proportion to viruses freely suspended in estuarine water could be more accurately determined. Poliovirus was found to adsorb readily to natural marine sediments collected along the Texas Gulf coast. A number of substances were evaluated for their ability to elute adsorbed viruses. A solution of 10% fetal calf serum adjusted to pH 10.5 and 0.05M ethylenediaminetetraacetate (pH 11.0) were found to be the best eluents. Using ethylenediaminetetraacetate as an eluent, it was possible to elute virus from large volumes of sediment and reconcentrate the sediment eluate into an economically assayable volume (30 to 50 ml). Poliovirus could be recovered from the sediment with an overall efficiency of 50%. This method was found to be satisfactory for the recovery of naturally occurring animal viruses in estuarine sediments from the upper Texas Gulf coast.

Edetic Acid↗
PubMed1977

Carpal tunnel syndrome: contribution of flexor tendons.

Tension in flexor tendons during wrist flexion may play a role in otherwise unexplained instances of the carpal tunnel syndrome. As the wrist is flexed, the median nerve in the tunnel bends around the taut flexor retinaculum. At the same time, the nerve is subject to compression against this ligament by tensed overlying flexor tendons that also bend around the ligament. Experimental data to support this possibility have been collected from cadaver hands. A pressure transducer has been substituted for the median nerve in the tunnel and registered sizable pressures when tension was applied to the flexor digitorum profundus tendons of the second and third digits during varying degrees of wrist flexion. If the profundus tendons are not tensed, pressure in the tunnel remains negligible until wrist flexion reaches its extreme. Thus, repetitive hand activities involving pinch or grasp during wrist flexion may be a contributing factor in some instances of the carpal tunnel syndrome.

Biomechanical Phenomena↗
PubMed1976

Anticoagulants for avian and reptilian blood: heparin and EDTA.

The effectiveness of EDTA (dipotassium and disodium salts) and heparin as anticoagulants for the blood of puffadders and pigeons has been investigated. In the case of the snakes all three substances produced haemolysis after variable time intervals, and increases in cell volume were observed. In the case of the pigeons, samples stored at 4 degrees C showed lower haematocrit values and haemolysed sooner than samples stored at room temperature.

Animals↗
PubMed1976

Significance of radiocontaminants in 123I for dosimetry and scintillation camera imaging.

Estimates of absorbed radiation dose and qualitative assessments of image resolution were compared for pure 131I and for 123I produced by the 122Te(d,n), 124Te(p,2n), and 127I(p,5n) 123Xe reactions. A substantial reduction in radiation dose is indicated when 123I replaces 131I, in spite of the radiocontaminants typically present 30-35 hr after the production of 123I by any of these methods. Only a marginal further reduction in radiation dose was noted with use of the most "pure" 123I as opposed to the least "pure" 123I. Comparable scintillation camera resolution was obtained for all 123I preparations at 30-35 hr after bombardment when the medium-energy and pinhole collimators were used. However, the radiocontaminants in the 123I produced from tellurium affected image resolution when the low-energy collimator was used.

Iodine Radioisotopes↗
PubMed1976

Estimates of radiation dose to the embryo from nuclear medicine procedures.

These phantom studies and computer calculations provide a direct means of estimating the radiation dose to the embryo resulting from the administration of a radiopharmaceutical to the mother during organogenesis. The specific absorbed fractions to the embryo from 19 source organs were computed for 12 monoenergetic photon energies. Tables of absorbed dose per unit cumulated activity, S, for the embryo as a target organ have been assembled for 99mTc, 111In, 113mIn, 123I, 131I, and 133Xe. In addition, the dose to the embryo was calculated for several of the radiopharmaceuticals for which the MIRD Committee has published dose estimate reports.

Embryo, Mammalian↗
PubMed1975

Ionic effects in the chromatography of proteins on columns of controlled-pore glass.

Bovine serum albumin, acetylcholinesterase and two non-protein markers were chromatographed on columns of controlled-pore glasses in buffer solutions of varied ionic strengths. Adsorption of protein to the glass and ionic effects due to repulsion of the negatively-charged solutes from the glass matrix were observed. When glasses were treated with Carbowax 20M, the adsorption disappeared but ion exclusion effects persisted. The ionic behavior of Carbowax-treated glasses was similar to that observed by one of the authors when using agarose columns.

Acetylcholinesterase↗
PubMed1975

Pattern of intellectual impairment in Huntington's chorea.

Cognitive function was evaluated in 11 patients with Huntington's chorea, using eight subtests of the WAIS, and their performance was compared with that previously reported for a normal aged population. The pattern of impairment was similar in the two groups. Tests of immediate memory were given to nine of these patients, and to 10 healthy but aged subjects. In both groups, there was a significant correlation between the performance of individuals in these tests and their IQ, suggesting that the choreic patients had no selective impairment of immediate memory. The clinical and psychological records of the 11 patients revealed no evidence of focal deficits, and the majority of patients were fully orientated and retained insight to their condition. These observations are discussed in relation to the pattern of intellectual impairment seen in other presenile dementias.

Adult↗
PubMed1975

Biological detection of reduction in dose at the surface of volume sources containing beta emitters.

Dosimetry theory related to volume sources containing uniformly distributed beta-emitting radionuclides predicts a rapid drop in dose at the outer surface to approximately one half of the maximum dose within the volume. The purpose of this study was to determine if this reduction in surface dose could be observed using a measurable biological endpoint. In this study rats were injected with radiocolloids of either 198Au, 113In-m or 99Tc-m, to produce liver irradiation from their decay, or their livers were treated with external X-irradiation. After irradiation, a portion of the liver was surgically removed to stimulate cell division in the liver remnant revealing radiation damage in the form of chromosomal aberrations. The percentages of dividing cells with bridges were scored in the outer edges (0.45 mm) of the tissue sections and were compared to levels obtained from the central portion of the liver lobe. No significant difference was observed with X-irradiation or from 99Tc-m irradiation. However, irradiation with 198-Au and 113In-m (which emit large numbers of energetic electrons) produced significantly fewer aberrations in the outer layer when compared to the central portion. These differences in the distribution of biological damage allowed us to detect the predicted dose reduction at the surface of volume sources containing beta emitters.

Animals↗