Showing papers by "University of Louisville published in 1973"
TL;DR: Factors that influence production of exotoxin A by a nonproteolytic strain of Pseudomonas aeruginosa (PA-103) were studied and pure proteins, such as crystalline bovine albumin, enhanced growth as well as production of toxin.
192 citations
TL;DR: In this paper, an approximation to the Voigt function is described, which is valid over the entire domain of the independent variables that characterize it and which is accurate to the order of 0.0001 of the peak value of the function.
Abstract: An approximation to the Voigt function is described, which is valid over the entire domain of the independent variables that characterize it and which is accurate to the order of 0.0001 of the peak value of the function. Relations between the parameters of the function are also given. The approximation is used to develop a procedure for fitting observed lines with Voigt functions; the class of asymmetric lines that arise from the superposition of two Voigt functions is considered in some detail, and methods for extracting the Voigt parameters of the components from the observed contour of the envelope are given. The measurement of the width and shape of a single line with a Fabry–Perot interferometer is also discussed. All of the calculations described here can be handled by programmable calculators or small computers.
175 citations
TL;DR: Using the atrioventricular and semilunar valves as ultrasonic landmarks, a simple reproducible technic is described for the ultrasonic evaluation of the heart and its great vessels in the normal neonate.
Abstract: Utilizing the atrioventricular and semilunar valves as ultrasonic landmarks, a simple reproducible technic is described for the ultrasonic evaluation of the heart and its great vessels in the normal neonate. The importance of the clinical application of this method is discussed.
Echocardiographic studies were performed on 240 normal newborns. Qualitative assessment was made of the interrelationships of the pulmonary, aortic, tricuspid, and mitral valves, and of interventricular septal motion. Quantitative norms were obtained for the following parameters: amplitude of motion of anterior leaflets of tricuspid and mitral valves, anteroposterior diameter of the ventricular and left atrial cavities, thickness of ventricular walls and interventricular septum, outside diameter of aortic and pulmonary roots, and interaortic and interpulmonary cusp distances.
117 citations
115 citations
TL;DR: Exotoxin A of Pseudomonas aeruginosa (PA-103) could be concentrated readily by precipitation with zinc acetate and ammonium sulfate and was purified by column chromatography with use of DEAE-cellulose and Sephadex G-200.
Abstract: Exotoxin A of Pseudomonas aeruginosa (PA-103) could be concentrated readily by precipitation with zinc acetate and ammonium sulfate. The toxin was purified by column chromatography with use of DEAE-cellulose and Sephadex G-200. The final product contained about 8,000 mouse LD,,0/mg of protein. The toxin has a sedimentation constant of 3.35 S, and the molecular weight is estimated to be in the range of 50,000. The toxin is readily inactivated by trypsin and by heating at 70 C for 30 min. It can also be inactivated by incubation with sodium deoxycholate but not by similar treatment with sodium glycocholate, sodium cholate, or lauryl sulfate. Efforts to convert this toxin to toxoid so far have been unsuccessful.
101 citations
Journal Article•
TL;DR: Rabbit's eyes were exposed to various levels of measured illumination for four hours and two sources with different spectral content were compared, showing that the visible portion of the spectrum is primarily responsible for retinal damage under these conditions.
Abstract: Rabbit's eyes were exposed to various levels of measured illumination for four hours. Two sources with different spectral content were compared for their ability to cause retinal damage. The damage was assessed by ophthalmoscopy, electroretinography, and histology. The threshold for minimal detectable damage with a broad-spectrum source occurred around 0.045 watt per square centimeter. A monochromatic source at 514.5 nm. produced damage at one fifth this power level. When the tivo sources were matched by electroretinography for visual efficiency in the rabbit, the thresholds for damage were approximately equal. This shows that the visible portion of the spectrum is primarily responsible for retinal damage under these conditions.
83 citations
TL;DR: Definitive diagnosis utilizing aortography to identify the site of the intimal tear and the extent of the dissecting hematoma plus evaluation of the general condition of the patient are the keys to the best use of those two modes of therapy and should lead to a success rate of 90% or better in the near future.
73 citations
Journal Article•
TL;DR: Photopic directional sensitivity was measured at the fovea and at 2°, 3.75°, and 10° from fixation and corroborating earlier observations that receptors across the retina are aligned with the point approximating the center of the exit pupil of the eye is presented.
Abstract: Photopic directional sensitivity was measured at the fovea and at 2°, 3.75°, and 10° from fixation (referred to the center of the entrance pupil of the eye; nonfoveal tests were conducted in the nasal field projected onto temporal retina). These data confirm and extend an earlier experiment performed by Westheimer. The central fovea exhibited significantly less directionality than parafoveal test points. Differences in directionality between the three parafoveal test loci were not significant. Possible factors giving rise to the foveal-parafoveal difference in directionality are reviewed. Evidence corroborating our earlier observations that receptors across the retina are aligned with the point approximating the center of the exit pupil of the eye is also presented.
66 citations
TL;DR: A dense material, apparently derived from transforming bodies in the cells, coats the plasma membrane of the surface cells, presumably to strengthen them.
Abstract: As the digital pad cells grow from the germinal epithelium, the desmosomes on the distal surface oF tile cells become aligned and form pegs filled with tonofilaments on the surface of the outer row of cells. The outer pad cells are separated from each other distally, thus the cell and the pegs form two sizes of protrusions in series on the pad surface which can fit into substratum/irregularities. A dense material, apparently derived from transforming bodies in the cells, coats the plasma membrane of the surface cells, presumably to strengthen them.
55 citations
TL;DR: The results suggest the presence of specific receptors for PGE 1 and HCG in the cell membranes and that the binding occurs either at two different sites on the same receptor or that each binds to a “different” receptor molecule.
54 citations
TL;DR: It appears that cyciodextrin stationary phases are useful for fractionation of nucleic acids and of other classes of compounds with functional groups which can interact with cyciodesxtrin cavities.
Abstract: The characterization by UV spectral methods of the interaction between cyclodextrins and nucleic acid components yields the following information. Adenine nucleotides are found to interact most strongly with cycloheptaamylose, presumably by inclusion of the base within the cyciodextrin cavity. Factors influencing the interaction include pH, the position of phosphorylation of nucleotides, and the degree of polymerization of oligonucleotides. When epichloro-hydrin cross-linked cycloheptaamylose gel is used as a stationary phase for nucleic acid chromatography, adenine-containing compounds are retained most strongly. The factors affecting complex formation with free cycloheptaamylose have the same effects on gel chromatography of nucleic acids. It appears that cyciodextrin stationary phases are useful for fractionation of nucleic acids and of other classes of compounds with functional groups which can interact with cyciodextrin cavities.
TL;DR: Since some glands secrete onto the dorsal epidermis of the digits, the mucous is believed to function as a wetting agent for the skin as well as an aid to climbing.
Abstract: The mucous glands consist of a single row of cells surrounded by smooth muscle. The cells are attached at their apical and basal regions and only cytoplasmic projections loosely link the lateral aspects of adjacent cells. Material accumulates in the cisternae of the rough endoplasmic reticulum, appears to form into dense granules in the Golgi apparatus, and then before being secreted, undergoes chemical and morphological alterations. Since some glands secrete onto the dorsal epidermis of the digits, the mucous is believed to function as a wetting agent for the skin as well as an aid to climbing.
TL;DR: A summary of the authors' work with methyl mercuric chloride in channel catfish illustrates the use of both histologic and histochemical techniques in assessing the prognosis of the effects of aquatic pollutants upon fish tissues.
Abstract: Application of histologic and histochemical techniques to the determination of effects of aquatic pollutants upon fish tissues is discussed. Definition of terms and techniques associated with appropriate preparation of tissue specimens are given. Illustrations include examples from control and altered tissues. A summary of our work with methyl mercuric chloride in channel catfish illustrates the use of both techniques in assessing the prognosis of the effects of aquatic pollutants upon fish tissues.
TL;DR: The findings seemed to indicate that neither the cell-bound protein toxin nor the lipopolysaccharide somatic antigen was an important factor in the pathogenesis of P. aeruginosa.
Abstract: Antitoxic sera were produced in rabbits, goats, and ponies with purified exotoxin A of Pseudomonas aeruginosa (strain PA-103). None of these sera contained agglutinating antibody against the bacterial cells, and all antitoxins appeared in the IgG fraction. Antitoxic titers of pony sera tended to be higher than those obtained with other animals, and 1 ml of these sera neutralized as much as a 5,000 mouse LD50 dose of toxin. The antitoxic sera, when given in sufficient quantity, could prevent the lethal effects of infection caused by strains of P. aeruginosa whose somatic antigens were unrelated to those of strain PA-103, provided the serotype of the exotoxin produced by the organisms was identical. Antitoxin A did not neutralize the cell-bound protein toxins of these organisms. The findings seemed to indicate that neither the cell-bound protein toxin nor the lipopolysaccharide somatic antigen was an important factor in the pathogenesis of P. aeruginosa.
TL;DR: Some parallel perceptual processing of the inputs to the two hands and mutual interference in processing inputs from fingers on the same hand are indicated.
Abstract: Can tactual information be acquired simultaneously by several different fingers? Blind and sighted Ss were asked to scan vertical displays of braille (consisting of either one or two dots) with the index and middle fingers on each hand-using one, two, or four fingers at the same time. Stimuli were recognized most rapidly when the displays were scanned by two fingers on different hands and least rapidly when two fingers on the same hand were used; performance was similar with one finger and with four fingers. The results indicated some parallel perceptual processing of the inputs to the two hands and mutual interference in processing inputs from fingers on the same hand.
TL;DR: It is suggested that P. aeruginosa, so prevalent with cystic fibrosis, has an inhibitory effect on C. albicans and that this interaction is effective to some extent in preventing candidal infection.
Abstract: The mycotic and bacterial flora of 65 patients with cystic fibrosis was studied.C. albicans andP. aeruginosa were present in 33% and 43% of sputa samples, respectively; only 6.5% harbored both organisms. The mycotic flora of the nasopharynx, rectum and skin of the cystic fibrosis patients was similar to that of children with other chronic lung diseases and to that of normal children.In vitro studies clearly revealed inhibition ofC. albicans byP. aeruginosa. It is suggested thatP. aeruginosa, so prevalent with cystic fibrosis, has an inhibitory effect onC. albicans and that this interaction is effective to some extent in preventing candidal infection.
TL;DR: Human serum albumin was separated by Sephadex gel filtration into monomeric, dimeric, and tr meric-polymeric fractions and electrophoresis in dodecyl sulfate polyacrylamide gel showed that dimerization was followed by trimer and tetramer formation.
TL;DR: It is found that the teichoic acid of Bacillus subtilis 168 (trp C2) would precipitate with con A at neutral pH in dilute buffer, and the formation of a precipitate was inhibited by sugars which bind to the active site of con A.
Abstract: A column of insoluble concanavalin A was prepared by coupling the protein to cyanogen bromide-activated Sepharose. When autolysates of Bacillus subtilis 168 cell walls were passed over the column, the alpha glucosylated teichoic acid component of the cell wall was retained. The teichoic acid could be eluted with dilute alpha-methylglucopyranose. The teichoic acid prepared by affinity chromatography from cell wall autolysates had a higher sedimentation rate than teichoic acids obtained by conventional methods. Several authors have shown that concanavalin A (con A) forms complexes with alpha-glucosylated teichoic acids1–3. Doyle and Birdsell1 found that the teichoic acid of Bacillus subtilis 168 (trp C2) would precipitate with con A at neutral pH in dilute buffer. The formation of a precipitate was inhibited by sugars which bind to the active site of con A. This observation suggested that it should be possible to purify the teichoic acid by affinity chromatography using insoluble con A as the affin...
TL;DR: Four lead peroxide and two nonlead peroxide impression materials and a polyether rubber were used to test the accuracy of stone dies reproduced from a master model and the most accurate dies were produced from polyether Rubber.
Abstract: Four lead peroxide and two nonlead peroxide impression materials and a polyether rubber were used to test the accuracy of stone dies reproduced from a master model. The most accurate dies were produced from polyether rubber, and the second most accurate were produced from a nonlead peroxide rubber.
TL;DR: In this article, both impregnated and non-impregnated marble specimens were subjected to 3000 ppm SO2 atmospheres in a dynamic system and X-ray diffraction and fluorescence studies to determine the deterioration quantitatively, revealed that transformation of the outer layer of non-imaged marble into primarily calcium sulfite stopped after a maximum 15 mole percent conversion under normal conditions of humidity.
Abstract: Marble specimens were impregnated with epoxy resins by first soaking the specimens in a solvent and then treating them, in steps, with increasing concentrations of the resin in the resin-solvent mixture. This resulted in impregnation to several centimeters’ depth into the specimen. Both impregnated and non-impregnated specimens were subjected to 3000 ppm SO2 atmospheres in a dynamic system. X-ray diffraction and fluorescence studies to determine the deterioration quantitatively, revealed that transformation of the outer layer of non-impregnated marble into primarily calcium sulfite stopped after a maximum of 15 mole percent conversion under normal conditions of humidity. While certain impregnated marble specimens showed significant protection from SO2 attack, other impregnated specimens revealed more reactivity than the controls. A partial explanation of this has been obtained by scanning electron microscopy which showed that the resin films on the surface were perforated. Coatings of certain acry...
TL;DR: In this article, the electrical transfer process involved in color changes in Fe-doped SrTiO3 was studied by Mossbauer methods, and it was found that the yellow samples contained Fe3+ ions, while the dark samples containedFe3+ and Fe4+ ions.
TL;DR: The steady state levels of aspartate, glutamate, and γ-aminobutyrate were determined in the brains of mice 10, 18, 29, and 36 months old, and the mice in all the age groups had the same brain concentration of glutamate.
TL;DR: Preoxidation of sections with 10% H2O2 acidified with H2SO4 (HPSA) to pH 3.2 prevents the common occurrence of Schiff background staining in glutaraldehyde-fixed tissues and permits optimum penetration of staining solutions.
Abstract: Reliable production and identification of Schiff-positive sites on glutaraldehyde-osmium fixed 0.5–1 μsm Epon sections is accomplished by preoxidation of sections with 10% H2O2 acidified with H2SO4 (HPSA) to pH 3.2 (Pool, C. R., Stain Techn., 44: 75–9, 1969). Light green as a counterstain is used. Steps in the procedure are: HPSA, 1–2 min at 25–30 C; washing; 1% light green 3–5 min; brief rinse; Schiff reagent 1–3 min; washing; drying; clearing in xylene and mounting in resin. The use of acidified H2O2 prevents the common occurrence of Schiff background staining in glutaraldehyde-fixed tissues and permits optimum penetration of staining solutions. Sections were attached to glass slides without adhesive and were processed in Coplin jars. Prior to drying, excess solutions should be drained and wiped away with lens tissue to prevent formation of precipitate on the sections.
TL;DR: Taurine is proposed to be a neuro-transmitter and has been shown to be released from electrically stimulated rat cortical slices and spinal cord slices, indicating its physiological role in muscles and nerves is not well understood.
Abstract: ALTHOUGH taurine is a major amino acid in muscles and nerves its physiological role is not well understood1. It has been proposed to be a neuro-transmitter and has been shown to be released from electrically stimulated rat cortical slices2 and spinal cord slices3.
TL;DR: In a small group of patients a definite improvement in the control of the disease and survival at two years was obtained with a combination of preoperative radiation therapy (3,000 rads in fourteen days) and surgery for Stages III and IV cancers.
Abstract: Summary The selection of treatment for early localized squamous cancer of the floor of the mouth must be based on a number of factors in addition to the extent of disease. The general health and nutrition of the patient, his smoking and drinking habits, and his mental and psychologic makeup must also be considered in deciding on the individual treatment modality. In a small group of patients a definite improvement in the control of the disease and survival at two years was obtained with a combination of preoperative radiation therapy (3,000 rads in fourteen days) and surgery for Stages III and IV cancers. When the number of patients so treated is larger, the over-all survival in Stages III and IV should improve because fewer patients will die of uncontrolled cancer in the regional area.
TL;DR: In this article, it was shown that a regular semigroup is always a regular subsemigroup of S and investigated relationships between it and S, where = S is of particular interest.
Abstract: Suppose S is a regular semigroup and E is its set of idempotents. If E is subsemigroup of S, then S has been called orthodox and studied recently by Hall [3], Meakin [6], and Yamada [8]. In this paper we assume that E is not (necessarily) a subsemigroup of S and consider the subsemigroup generated by E, denoted . If E denotes the set of all elements of S which can be written E, denoted . If E denotes the set of all elements of S which can be written as the product of n (not necessarily distinct) idempotents of S, then . We show that is always a regular subsemigroup of S and investigate relationships between it and S. The case where = S is of particular interest to us; such semigroups will be referred to as idempotent-generated regular semi- groups.
TL;DR: It was suggested that insights into feature analysis of processes involved in form identification might be gained from an analysis of eye movements made by Ss as they identified patterns.
Abstract: It was suggested that insights into feature analysis of processes involved in form identification might be gained from an analysis of eye movements made by Ss as they identified patterns. Fixations were measured during identifications of histoforms, polygons, and Vargus 10 figures. Eye fixations were measured, and Ss rated sections of the figures in terms of their importance. Eye fixations were measured in terms of number of changes and duration of fixations. The number of changes in fixation were found to reflect only individual differences. Duration of fixation was found to vary significantly with location within figures, with fixations being longest where changes of contour occurred. There was also a tendency to look longer at the top of polygons and Vargus 10 figures and at the center of histoforms. Ratings of importance were highest for sections of figures fixated for longer duration-generally areas in which changes of contour were present.
TL;DR: The phytohemagglutinin, concanavalin A (Con A), interacts specifically and reversibly with the alpha-d-glucose-substituted polyglycerol phosphate teichoic acids of Bacillus subtilis 168.
Abstract: The phytohemagglutinin, concanavalin A (Con A), interacts specifically and reversibly with the α-d-glucose-substituted polyglycerol phosphate teichoic acids of Bacillus subtilis 168. Teichoic acids from nonglucosylated strains (mutants resistant to phage 25) interact weakly, if at all, with Con A. Prior treatment of glucosylated cell walls with Con A results in a concentration-dependent inhibition of phage 25 adsorption. The inhibition of adsorption to glucosylated cell walls occurs immediately upon the formation of the Con A-cell wall complex and is reversed upon dissociation of the complex by addition of α-methyl glucose. Examination of the interaction between Con A and whole cells, cell walls, or wall digests from glucosylated (phage-sensitive) and non-glucosylated (phage-resistant) strains further demonstrates the specificity of the reaction. A conditional phage 25-resistant mutant only forms complexes with Con A when grown under permissive conditions.