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Biomedical subjects

W S Smith

Publications and source records attributed to W S Smith.

At least 55 records · Page 3Linked to original sources
PubMed1992

The injuries to JFK.

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Craniocerebral Trauma↗
PubMed1989

Proton NMR study of the influence on iron oxidation/ligation/spin state on the heme orientational preference in myoglobin.

Proton nuclear magnetic resonance spectroscopy has been utilized to demonstrate that the degree of heme orientational disorder within a given myoglobin protein matrix can be a sensitive function of the oxidation/ligation/spin state of the heme iron. For sperm whale deuterohemin-reconstituted myoglobin, the equilibrium was found to strongly favor (5.7 to 7.8 kJ/mol) the X-ray characterized heme orientation in all six-coordinate states, but with a considerable reduction in preference (to 1.6 kJ/mol) in the five-coordinate deoxy state. In native yellow fin tuna myoglobin, changes in heme orientational preferences of approximately 3 kJ/mol occur even between two six-coordinate ferric states differing solely in spin states.

Animals↗
PubMed1989

Effects of synchrony between primate corticomotoneuronal cells on post-spike facilitation of muscles and motor units.

Cross-correlating the activity of neighboring motor cortex neurons recorded with independent electrodes in behaving monkeys has revealed synchronization peaks, largely due to common synaptic input. Corticomotoneuronal (CM) cells produced post-spike facilitation (PSF) of rectified forearm electromyograms (EMG); 15 cells synchronized with CM cells showed no PSF. Five pairs of CM cells with overlapping muscle fields exhibited similar synchrony peaks. The contribution of this synchrony to facilitation of common target muscles was assessed by two new methods: selective spike-triggered averaging and convolution. They showed that the PSF is composed predominantly of effects mediated by output of the triggering cell, but may include a broad, shallow component mediated by synchrony with other CM cells.

Action Potentials↗
PubMed1988

Solvent isotope effects on NMR spectral parameters in high-spin ferric hemoproteins: an indirect probe for distal hydrogen bonding.

The influence of solvent isotope composition on 1H-NMR resonance position and linewidth of heme methyls has been investigated for a variety of high-spin ferric hemoproteins for the purpose of detecting hydrogen-bonding interactions in the heme cavity. Consistently larger hyperfine shifts and paramagnetic linewidths in 2H2O than 1H2O are observed for metmyoglobins and methemoglobin possessing a coordinated water molecule. The analysis of the dynamics of labile proton exchange in sperm whale metmyoglobin, and the absence of any isotope effects in the five-coordinate Aplysia metmyoglobin, indicate that the significant axial modulation of heme electronic structure by solvent isotope is consistent with arising from distal hydrogen-bonding interactions. The presence or absence of similarly large isotope effects on shifts and linewidths in other hemoproteins, depending on the presence of a bound water in the distal heme pocket, suggests that this isotope effect can serve as a probe for the presence of such bound water. The absence of any detectable isotope effect on either shifts or linewidths in resting-state horseradish peroxidase supports a five-coordinate structure with bound water absent from the vicinity of the iron.

Animals↗
PubMed1988

Replantation of an autoclaved autogenous segment of bone for treatment of chondrosarcoma. Long-term follow up.

Seven patients who had a low-grade chondrosarcoma of the proximal part of the humerus or femur were treated by resection, autoclaving of the excised segment, and reinsertion of that segment with supplementary fresh autogenous grafts. The length of follow-up ranged from fourteen to twenty-four years, and sequential roentgenograms were made during the follow-up period. A biopsy of the autoclaved segments was done in one patient eleven years after the operation, and examination of the specimen showed predominantly live bone; there were very few spicules of dead bone. Although the principal roentgenographic changes were demonstrated by the end of the first year, serial roentgenograms showed a continuing process of remodeling for two decades. No secondary procedures were required for treatment of fracture, resorption, infection, or loss of function.

Adult↗
PubMed1985

Proton NMR study of yellowfin tuna myoglobin in whole muscle and solution. Evidence for functional metastable protein forms involving heme orientational disorder.

Proton NMR spectra of met-aquo-myoglobin have been recorded in whole dark muscle from yellowfin tuna for the first time; in addition, spectra of the met-aquo, met-cyano, and deoxy forms were recorded in solution. The number of resolved methyl resonances in the met-aquo and met-cyano derivatives of the purified protein indicates a molecular heterogeneity, with the two species present in a ratio of approximately 3:2. These same two species, in very similar environments, are found in whole muscle. Upon reconstitution of the protein, the ratio of the two species is approximately 1:1. Specific isotope labeling in the met-cyano form reveals an interchange of 5-methyl and 8-methyl environments that is characteristic of heme orientational disorder about the alpha, gamma-meso axis. Incubation of the met-cyano protein at 37 degrees C shows that the two species are interconvertible, with the minor component declining to about one-eighth of that of the major component. This indicates that one of the two orientations is favored thermodynamically. The rate of equilibration for the met-aquo protein is exceedingly slow (half-life greater than 30 days), some 10(2) slower than for the analogous sperm whale derivative. The "reversed" heme orientation is therefore present in muscle as a kinetically trapped or metastable species, suggesting that the last step in the biosynthesis of myoglobin is similar to that of in vitro reconstitution. The presence of both heme orientations in myoglobin in whole muscle proves that heme orientational disorder is a physiological phenomenon.

Amino Acid Sequence↗
PubMed1984

Hypopyon in acute lymphoblastic leukemia.

A child with acute lymphoblastic leukemia had central nervous system relapse 23 months after diagnosis while in bone marrow remission. This was followed by leukemic involvement of the eye as the only site of relapse 7 months later. Leukemic cells layered out in the anterior chamber and cytologic examination was the only way to make a definitive diagnosis of leukemic hypopyon. Topical treatment is generally ineffective and radiotherapy is the treatment of choice. The prognosis with this complication depends on whether it occurs during therapy or after therapy has been discontinued.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1983

A microcomputer-based data acquisition system for continuous recording of feeding and drinking by rats.

A monitoring system to continuously record the daily pattern of drinking and eating of rats is described. This system, based on a North Star microcomputer, can record the amount of food ingested with a temporal resolution of +/- 1.0 second and quantitative accuracy within +/- 5%. Drinking behavior is detected using a drinkometer which also has a temporal resolution of +/- 1.0 second. Data are analyzed by computer to determine absolute amounts of consumption and patterns of intake. The patterns of feeding and drinking recorded by this system are similar to those observed using other monitoring devices.

Animals↗
PubMed1983

A randomized, double-blind, parallel group comparison of disopyramide phosphate and quinidine in patients with cardiac arrhythmias.

This report summarizes the results of a randomized, double-blind, parallel group, multicenter study which compared the antiarrhythmic activity and safety of oral disopyramide phosphate and oral quinidine sulfate. A total of 124 outpatients, whose pretreatment rates of ventricular and/or supraventricular arrhythmias were documented by ambulatory ECG recordings, were randomly assigned to receive either oral disopyramide or oral quinidine for the eight-week course of the study. Every two weeks, ten-hour ambulatory ECG recordings were obtained from each patient and blood was drawn to determine serum concentrations of assigned drug.

Administration, Oral↗
PubMed1983

[Not Available].

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Australia↗