Showing papers by "Saint Louis University published in 1979"
TL;DR: The results of this study showed that the EMG is a complex waveform, being influenced not only by fatigue, but to even a larger extent in many cases, the temperature of the exercising muscles.
Abstract: The surface EMG was recorded from above the quadriceps muscle in 3 male subjects during bicycle ergometry at work loads between 20 and 100% of the VO2 max to measure the EMG amplitude (RMS) and frequency (assessed from the center frequency of the power spectra) during this type of work During brief (3 min) bouts of work the RMS amplitude of the EMG was linearly related to the work load; the center frequency of the EMG power spectra was the same at all work loads examined In contrast, during sustained bouts of work maintained for 80 min at 20 and 40% of the VO2 max, the RMS amplitude of the EMG remained constant while the center frequency initially increased for the first 20 min of work and then progressively decreased as the work continued When work loads of 60, 80, and 100% of the VO2 max were sustained to fatigue, the RMS amplitude continually increased while the EMG frequency decreased from the beginning to the end of the work periods The results of this study showed that the EMG is a complex waveform, being influenced not only by fatigue, but to even a larger extent in many cases, the temperature of the exercising muscles Therefore, although muscular fatigue caused an increase in the RMS amplitude and decrease in the center frequency, the increase in muscle temperature associated with the work opposed these changes by causing a reduction in the RMS amplitude and an increase in the center frequency
228 citations
TL;DR: These DNA homology groupings are consistent in the main with the properties of other “groupings” of human Ads, e.g., oncogenic groups (tumorigenicity in newborn hamsters), T-antigen groups, G + C content of viral DNA, hemagglutination groups, molecular characteristics of subviral particles and virion proteins, and human epidemiology and pathogenicity.
167 citations
TL;DR: The GTA of ten independently isolated wild-type strains of R. capsulata show a high degree of immunological cross-reactivity; thus this genetic exchange system, while not a species-wide trait, does seem to be the product of a conservative evolutionary process.
159 citations
147 citations
TL;DR: Girls were more cooperative in wearing headgear, which was related to their more general attitude of cooperation, and girls were motivated by dentofacial esthetics more than boys, who were more inclined to perceive the consequences of their actions as their personal responsibility.
138 citations
TL;DR: Five volunteer subjects held isometric handgrip contractions at specific submaximal tensions until the required tension could no longer be maintained, and sustained contractions showed that strength declined linearly at all tensions.
Abstract: Five voluntee subjects held isometric handgrip contractions at specific submaximal tensions until the required tension could no longer be maintained. At the start of those contractions, the amplitude of the surface electromyogram (EMG) was linearly related to the tension exerted; the amplitude of the EMG increased linearly throughout these substained contractions by a constant amount--about 30% of the maximum. During sustained contractions, brief, intermittent maximal efforts showed that strength declined linearly at all tensions. At 25% maximal voluntary contraction (MVC), there was a linear fall in the EMG amplitude associated with the brief maximal efforts, but the fall in strength was more rapid than the fall in EMG amplitude. At 70% MVC, there was no fall in the EMG amplitude in response to the brief maximal efforts, while the muscle strength fell linearly.
116 citations
TL;DR: Prophylactic digitalization demonstrates no benefit in the prevention of SVT following myocardial revascularization and may, in fact, predispose the patient to these arrhythmias.
115 citations
TL;DR: In this article, a single-station method along 33 Rayleigh-and 30 Love-wave paths across the Pacific was used to detect variations in upper mantle structure beneath the Pacific.
Abstract: Summary. Group and phase velocities for periods between 16 and 110 s have been determined using the single-station method along 33 Rayleigh-and 30 Love-wave paths across the Pacific. These dispersion data were used to detect variations in upper mantle structure beneath the Pacific. Taking both regional changes and azimuthal anisotropy into consideration, regionalized group and phase velocities were derived for four regions of differing age. The boundaries of the regions were chosen to correspond to isochrons of 20, 50 and 100 Myr, as inferred from geomagnetic lineations. A small, but significant degree of azimuthal anisotropy (less than 0.8 per cent) was found to occur throughout the Pacific if the degree and direction of maximum velocity were assumed to be uniform everywhere. The average direction of maximum velocity was found to be 85°± 6° as measured clockwise from north. Regionalized group and phase velocities for Rayleigh waves at the larger periods increase systematically with increasing age of the ocean floor. For Love waves, departures from a systematic increase occur in the youngest (0–20 Myr) and oldest (> 100 Myr) portions of the Pacific.
The dispersion data were corrected for the effects of anelasticity and were inverted to obtain shear velocity models for each of the four regions using the stochastic inversion method. A comparison of the shear wave models derived from Rayleigh waves in the four regions indicates that average shear velocities at depths between 30 and 110 km increase rapidly with age. This increase occurs mainly because the depth to the base of the lithosphere increases; however, the shear velocities of the lithosphere also increase for the regions out to 100 Myr in age. Slightly lower velocities in the upper part of the lithosphere for greater ages may be due to a large influx of mid-plate volcanism during the Cretaceous.
Separate inversions of Love-and Rayleigh-wave velocities indicate that polarization anisotropy can be resolved for the lithosphere. Polarization anisotropy cannot, be resolved for the low-velocity zone beneath the Pacific using these data, except possibly in the youngest regions, where lateral complexities of the East Pacific Rise are apt to affect the data adversely. Assuming that we can adequately invert our Love-and Rayleigh-wave data separately to obtain information on anisotropy, we find that average SV velocities in the lithosphere increase from about 4.3 to 4.6 km/s, and average SH velocities increase from about 4.5 to 4.7 km/s, from the youngest to oldest regions. Average velocities in the upper portion of the low-velocity zone increase from about 4.1 to about 4.25 km/s for the same regions.
The existence of anisotropy in the lithosphere is constant with the results of seismic refraction experiments in the Pacific and supports peroxide as the predominant upper mantle material. The occurrence of anisotropy through-out the entire lithosphere, suggests a situation in which periodite crystallizes at the base of the lithosphere from a partially molten low-velocity zone and olivine crystals become aligned in response to the stress field within the Pacific plate.
105 citations
88 citations
TL;DR: Pamamycin is a new antibiotic isolated from Streptomyces alboniger ATCC 12461 that is active in vitro against Gram-positive bacteria, Neurospora, and Mycobacteria.
Abstract: Pamamycin is a new antibiotic isolated from Streptomyces alboniger ATCC 12461. The antibiotic is active in vitro against Gram-positive bacteria, Neurospora, and Mycobacteria. The compound also acts as a streptomycete differentiation effector. It stimulates aerial mycelia formation in the producing organism. The new antibiotic of elemental composition C36H63NO7 is completely different from puromycin, also produced by this strain. The present communication deals with the isolation, properties, and preliminary characterization of pamamycin.
85 citations
TL;DR: In this paper, an empirical equation is derived to adjust the mb values obtained from intensity data so that they agree with the teleseismic P-wave magnitudes. But, this method cannot be used for estimating mb of all historical earthquakes because the intensity data are not always adequate.
Abstract: This paper is concerned with estimating body-wave magnitude, mb , from the intensity distribution of an earthquake. Initially, it is assumed that modified Mercalli (MM) intensity values are directly related to the ( A/T ) z values of 1-Hz, Lg -wave ground motion. By comparison with the intensity values of a reference earthquake, magnitudes are calculated for 41 western and central United States earthquakes. Magnitudes of these earthquakes also are determined independently, in the conventional manner, using teleseismic P -wave amplitudes. Comparison of the two sets of magnitude values indicates that the assumed relation between 1-Hz, Lg -wave ( A/T ) z values and MM intensity does not hold exactly over the mb range of 4.0 to 6.2. An empirical equation is derived to adjust the mb values obtained from intensity data so that they agree with the teleseismic P -wave magnitudes.
The method then is applied to estimate mb of some historical earthquakes which occurred prior to 1962. These include the set for which Kanamori and Jennings (1978) estimated ML from strong-motion accelerograms. Some noteworthy United States earthquakes also are considered. These include: the 1811 New Madrid earthquake for which mb is estimated to be 7.3; the 1886 Charleston, South Carolina earthquake, for which mb is estimated to be 6.6 to 6.9; the 1897 Giles County, Virginia earthquake, for which mb is estimated to be 5.8; the 1906 San Francisco, California earthquake, for which mb is estimated to be 6.8 to 7.1.
The intensity-attenuation method cannot be used for estimating mb of all historical earthquakes because the intensity data are not always adequate. In some cases, however, the total felt area or the area enclosed by the Modified Mercalli IV isoseism can be determined. It was found that empirical equations relating mb to these areas, which were derived for central and northeastern United States earthquakes, also apply for events in the southeast. These empirical methods are used to estimate mb values for a set of historical Virginia earthquakes.
TL;DR: Using this stimulation technique, tetanic contractions can be developed by muscle at low stimulation voltages and within physiological stimulation frequencies, unlike synchronous electrical stimulation, during sequential stimulation, submaximal tensions can be maintained for sustained periods of time.
Abstract: An electrode array is described that can be used to stimulate skeletal muscle through the peripheral motor nerves. This electrode array differs from the sleeve electrode that is used conventionally in that the motor units are stimulated sequentially, a mode of stimulation which closely mimics the normal asynchronous firing pattern of motor units that occurs during voluntary activity. Using this stimulation technique, tetanic contractions can be developed by muscle at low stimulation voltages and within physiological stimulation frequencies. Furthermore, unlike synchronous electrical stimulation, during sequential stimulation, submaximal tensions can be maintained for sustained periods of time. The applications of this electrode array to rehabilitation medicine are discussed
TL;DR: Gastroplasty is effective only when a small fundic reservoir is formed with a nonexpanding 12-mm channel and support of the channel with a seromuscular suture appears to achieve this goal.
TL;DR: In this paper, the three-temperature theory of gaseous ion transport is generalized to allow arbitrary choices for the parallel and perpendicular ion temperatures and the velocity displacement, and a truncation-parametrization sheme is proposed which simplifies the numerical computation.
TL;DR: Cold blood with potassium, 34 mEq/L, was compared with cold blood and with a cardioplegic solution, and ATP and ADP were lowest in hearts perfused with cardiographers, and CP and ATP did not return to control in any group.
TL;DR: A simple, understandable FORTRAN computer program for the location of hypocenters of local and regional earthquakes is presented, designed for interactive timesharing use and offers the ability to locate earthquakes quickly, obviating the need of punching data cards and submitting them to a central computer facility.
Abstract: A simple, understandable FORTRAN computer program for the location of hypocenters of local and regional earthquakes is presented. The program is designed for interactive timesharing use and offers the ability to locate earthquakes quickly, obviating the need of punching data cards and submitting them to a central computer facility. Variations of the program have been run on Honeywell 6023 and DEC PDP 11/70 computers.
TL;DR: It is shown that long-term survival and a small incidence of late myocardial infarction after myocardia revascularization are more likely in patients who undergo complete revascularizations before significant left ventricular myocardIAL damage has occurred.
Abstract: During 1970 to 1977, among 1,733 patients who underwent isolated coronary bypass grafting, the operative mortality was 2.5 percent. Actuarial 5 year survival is 88.1 percent. At an average follow-up of 46 months (range 13 to 108), 90 percent of patients remain angina-free or with symptomatic improvement. The 5 year survival rate of patients with single vessel coronary artery disease is 97.9 percent. In patients with multivessel disease, operative survival appears to be favorably influenced by the presence of normal preoperative ventricular function. Late survival is significantly better in patients with multivessel disease with normal preoperative ventricular function or with complete revascularization. Risk of perioperative myocardial infarction has been appreciably reduced by the introduction of cold potassium chloride cardioplegia. Late myocardial infarction has occurred at an average annual risk of 1.46 percent. These data show that long-term survival and a small incidence of late myocardial infarction after myocardial revascularization are more likely in patients who undergo complete revascularization before significant left ventricular myocardial damage has occurred.
TL;DR: Two temperature-sensitive nuclear mutants are identified that fail to excise the intervening sequence at the nonpermissive temperature (37 degrees C) and should provide powerful new tools for studying RNA processing in eukaryotic cells.
Abstract: Recent studies have shown that the gene encoding the large (25 S) mitochondrial rRNA of Neurospora crassa contains an intervening sequence of 2-2.5 kilobases that is not present in the mature 25S mitochondrial rRNA. Earlier studies had provided evidence that mitochondrial rRNAs in Neurospora are synthesized via a 32S precursor RNA that contains sequences for both the mature 19S and 25S RNA species. The present work shows that the intervening sequence is not present in 32S RNA. However, we have identified two temperature-sensitive nuclear mutants that fail to excise the intervening sequence at the nonpermissive temperature (37 degrees C). When grown at 37 degrees C, the mutants show decreased ratios of 25S to 19S RNA and accumulate a novel 35S RNA that appears to consist of 25S RNA plus most or all of the intervening sequence. The mutants are allelic but can be distinguished in temperature shift-up experiments, mitochondrial rRNA processing turning off more rapidly in one than in the other. These mutants should provide powerful new tools for studying RNA processing in eukaryotic cells.
TL;DR: Comparison of the relative specific activities of incorporated [1,2-3H2]-cholesterol indicate that 59% of the total surfactant cholesterol is located extracellularly, which suggests that most if not all ext racellular surfactants cholesterol is derived from the lamellar body.
TL;DR: Ionomycin, a recently discovered calcium ionophore, inhibits the ATP-dependent active Ca2+ transport of rabbit sarcoplasmic reticulum vesicles at concentrations as low as 10(-8) to 10(-6) M.
TL;DR: In this article, it was shown that earthquakes that occur outside the recognized seismic zones or major structural features will have a maximum body-wave magnitude m/sub b/ of 5.5 and that this maximum value will occur only infrequently.
Abstract: The combination of moderate seismic activity, sparsity of seismograph stations and relatively low density of population makes it difficult to assign quantitative seismicity values to most of the central United States. The seismicity data suggest that earthquakes that occur outside the recognized seismic zones or major structural features will have a maximum body-wave magnitude m/sub b/ of 5.5 and that this maximum value will occur only infrequently. Experience shows that if these relatively minor earthquakes are only a few kilometres deep they may have an epicentral intensity at least as large as VII (observed for an earthquake of m/sub b/ = 3.8), but their magnitude and area of perceptibility will be small. With the exception of the New Madrid seismic zone and possibly the Wabash Valley seismic zone, a conservatively reasonable value for the maximum body-wave magnitude to be expected in the major seismic and structural zones of the central United States is 6.5. For the New Madrid seismic zone an earthquake of body-wave magnitude equivalent to that of a great earthquake (m/sub b/ = 7.5) can be expected, on the basis of what has already been experienced in 1811-1812. Because of low anelastic attenuation, the earthquakes in the centralmore » United States are felt and cause damage over much wider areas than earthquakes of comparable magnitude in the western United States. Further consequences are that the ground shaking has a longer duration and that the ground-motion spectrum shifts at the larger distances to lower frequencies, which results in relatively low ground acceleration for relatively large ground displacements and a greater effect on high-rise than low-rise structures. (JMT)« less
TL;DR: Rabbit muscle creatine kinase catalyzes transphosphorylation between ATP and β-guanidinopropionate at pH 9 and 23°C with a K m for β- GU of 50 m m and a V max of 0.22 in comparison to the comparable values for the phosphorylation of creatine.
TL;DR: Levels of DNLCA in brain of treated animals were more than tenfold higher than controls, and the excess tetrahydroisoquinoline appeared to accumulate in the cerebellum and cortex.
Abstract: 3',4'-Deoxynorlaudanosolinecarboxylic acid (DNLCA), a tetrahydroisoquinoline derived from dopamine and phenylpyruvic acid, has been detected by computerized mass fragmentography in urine of phenylketonuric children and in urine and brain of rats with experimentally induced hyperphenylalaninemia. Levels of DNLCA in brain of treated animals were more than tenfold higher than controls, and the excess tetrahydroisoquinoline appeared to accumulate in the cerebellum and cortex. DNLCA is a noncompetitive inhibitor of dopamine beta-hydroxylase (inhibition constant, Ki, = 0.42 mM) and is taken up by the brain.
TL;DR: It is shown here that the 53Ks precipitated by three of these antisera as well as Adl-SV40 induced hamster tumor sera all have identical two-dimensional tryptic [35S]Met-peptide maps, and concludes that early region 1 codes for two (53K/15K family, 40K–50K family) or possibly more (e.g., 11K–12Kfamily) families of polypeptides.
TL;DR: The technique of fluorescence photobleaching recovery for measurement of absolute diffusion constants of a number of fluoiescein isothiocyanate-labeled proteins has sufficient sensitivity to reveal the concentration dependence at neutral pH of the diffusion constant of alpha-chymotrypsin.
TL;DR: Neurospora crassa mitochondrial deoxyribonucleic acid shows strict uniparental inheritance in sexual crosses, with a notable absence of mixtures and recombinant types that appear frequently in heteroplasmons.
Abstract: Neurospora crassa mitochondrial deoxyribonucleic acid shows strict uniparental inheritance in sexual crosses, with a notable absence of mixtures and recombinant types that appear frequently in heteroplasmons.
TL;DR: In this paper, a large-signal transistor model is developed, based upon modifications to standard Ebers-Moll formulations for bipolar transistors, with ranges of parameters given based on a simplified analysis of rectification in ideal diodes.
Abstract: This paper develops analytical techniques for the study of nonlinear RF and microwave effects in semiconductor devices. Rectification in p-n junctions is discussed, and a novel large-signal transistor model is developed, based upon modifications to standard Ebers-Moll formulations for bipolar transistors. Use of the models in worst-case analysis is discussed, with ranges of parameters given based on a simplified analysis of rectification in ideal diodes.
TL;DR: Two-dimensional gel analysis shows that the more slowly sedimentaing CAP-30S particles are deficient in S-5 and in several other proteins, whereas these proteins are present in normal concentrations in mature small subunits from the same cells, which is consistent with a defect in a mit ribosomal constituent in [poky].
Abstract: Recent results with Neurospora crassa show that one protein (S-5, mol wt 52,000) associated with the mitochondrial (mit) small ribosomal subunit is translated within the mitochondria (Lambowitz et al. 1976. J. Mol. Biol. 107:223-253). In the present work, Neurospora mit ribosomal proteins were analyzed by two-dimensional gel electrophoresis using a modification of the gel system of Mets and Bogorad. The results show that S-5 is present in near stoichiometric concentrations in high salt (0.5 MKCl)-washed mit small subunits from wild-type strains. S-5 is among the most basic mit ribosomal proteins (pI greater than 10) and has a high affinity for RNA under the conditions of the urea-containing gel buffers. The role of S-5 in mit ribosome assembly was investigated by an indirect method, making use of chloramphenicol to specifically inhibit mit protein synthesis. Chloramphenicol was found to rapidly inhibit the assembly of mit small subunits leading to the formation of CAP-30S particles which sediment slightly behind mature small subunits (LaPolla and Lambowitz. 1977. J. Mol. 116: 189-205). Two-dimensional gel analysis shows that the more slowly sedimentaing CAP-30S particles are deficient in S-5 and in several other proteins, whereas these proteins are present in normal concentrations in mature small subunits from the same cells. Because S-5 is the only mit ribosomal protein whose synthesis is directly inhibited by chloramphenicol, the results tentatively suggest that S-5 plays a role in the assembly of mit small subunits. In addition, the results are consistent with the idea that S-5 stabilizes the binding of several other mit small subunit proteins. Two-dimensional gel electrophoresis was used to examine mit ribosomal proteins from [poky] and six additional extra-nuclear mutants with defects in the assembly of mit small subunits. The electrophoretic mobility of S-5 is not detectably altered in any of the mutants. However, [poky] mit small subunits are deficient in S-5 and also contain several other proteins in abnormally low or high concentrations. These and other results are consistent with a defect in a mit ribosomal constituent in [poky].
TL;DR: Two variant mtDNA types have been identified in individual subcultures of the extra-nuclear [poky] mutant of Neurospora crassa, and data are presented which suggest that this alteration may be located near small deletions and/or sequence changes in Eco RI-3 and -10, fragments almost exactly opposite the site of the repeats on the genome.
TL;DR: Evidence has been presented indicating that the calcification nodules arise from smaller mineralization foci, presumably matrix vesicles, at which point development is slowed or halted allowing the formation of the peripheral dense zone.
Abstract: Osteolathyrism has been used as an experimental model for the study of calcification nodules during the mineralization process. Periosteal exostoses developing in osteolathyrism characteristically have spherical basophilic structures (calcification nodules) in the vicinity of developing bone spicules. In thin sections, the nodules were seen scattered between collagen fibers in the intercellular matrix. Collagen fibers did not appear to be present within the nodules but sometimes were packed just outside them. Matrix vesicles were also present in areas of early mineralization.