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Biomedical subjects

R T Jones

Publications and source records attributed to R T Jones.

At least 235 records · Page 13Linked to original sources
PubMed1981

Isolation and partial characterization of a major peanut allergen.

We isolated and partially characterized a major peanut allergen (Peanut-I) using the radioallergosorbent test (RAST) to monitor the allergenicity of various fractions. Raw peanuts were pulverized, defatted, and extracted; the resulting crude extract (CPE) was fractionated by diethylaminoethyl (DEAE) cellulose anion-exchange chromatography using a linear salt gradient. Peak allergenic fractions were further purified by a second DEAE cellulose chromatography step, followed by a preparative polyacrylamide gel electrophoresis (PAGE) step. The final product, Peanut-I, contained 11% nitrogen and 8.7% carbohydrate and was homogeneous by both analytical PAGE and immunoelectrophoresis against rabbit anti-CPE. Peanut-I was heterogeneous by thin-layer electrofocusing and by PAGE in 1% sodium dodecyl sulfate. Biologic activity of Peanut-I was demonstrated by positive skin tests and leukocyte histamine release assays in patients with peanut allergy. By RAST inhibition assay Peanut-I did not account for all of the allergenic activity of CPE.

Allergens↗
PubMed1981

Allergenicity of various peanut products as determined by RAST inhibition.

Extracts of 19 different peanut products and peanut oil were tested for their allergenicity by the radioallergosorbent test inhibition assay using a crude peanut extract from raw peanuts as the standard for comparison. Seventeen of the extracts were able to competitively inhibit the binding of serum IgE from peanut-sensitive patients with the solid-phase raw peanut extract. Peanut oil and the extract from hydrolyzed peanut protein did not inhibit binding, which suggests that these products are not allergenic. The peanut hull flour extract showed a slight ability to inhibit binding, suggesting that this product contains minor amounts of the peanut allergen.

Allergens↗
PubMed1981

Social validation and training of emergency fire safety skills for potential injury prevention and life saving.

A multifaceted behavioral program designed to teach emergency fire escape procedures to children was evaluated in a multiple-baseline design. Five children were trained to respond correctly to nine home emergency fire situations under simulated conditions. The situations and responses focused upon in training were identified by a social validation procedure involving consultation with several safety agencies, including the direct input of firefighters. Training, carried out in simulated bedrooms at school, resulted in significant improvements in both overt behavior and self-report of fire safety skills. The gains were maintained at a post-check assessment 2 weeks after training had been terminated. The results are discussed in relation both to the importance of social validation of targets and outcomes and the implications for further research in assessing and developing emergency response skills.

Accident Prevention↗
PubMed1981

Long-term survival of normal adult human tissues as xenografts in congenitally athymic nude mice.

Bronchi, pancreatic ducts, and colons from adult human were maintained as xenografts in congenitally athymic nude N:NIH(S) mice for 715, 145, and 89 days, respectively. After an ischemic crisis and revascularization of the human tissue, the epithelium regenerated to a normal differentiated morphology. The long-term survival of normal adult human epithelial tissues as xenografts provides model systems for the study of the interactions of chemical and/or physical carcinogens with human tissues.

Animals↗
PubMed1981

Pathophysiology of hemorrhagic shock. II. Anoxic metabolism of the rat liver following acute blood loss in the rat.

Changes in energy metabolism of rat liver in hemorrhagic shock were investigated. The hepatic energy charge level (0.24-0.693) correlated significantly with the mean arterial blood pressure (20-75 mmHg) (r = 0.931, P less than 0.001), as well as the blood volume withdrawn (2.43-2.82 ml/100 g body weight) which, in turn, correlated with the various mortality rates (LD16, LD50, and LD84) (r = -0.728, P less than 0.01). As shown by the changes in adenylate energy charge levels, the liver was very sensitive to acute blood loss. There was no significant difference between the energy charge levels of liver obtained in situ from rats with 84% mortality after hemorrhage and that of the same liver further incubated in vitro in the absence of O2 (0.304 versus 0.235). From these results, it appears that the energy status in the liver of rats dying from severe hemorrhagic shock has changed to anaerobic metabolism, which may not be sufficient to maintain adequate liver function or support individual survival.

Acute Disease↗
PubMed1981

Pathophysiology of hemorrhagic shock. A role of arterial ketone body ratio as an index of anoxic metabolism of the liver in acute blood loss.

The changes in the oxido-reduction state and the adenylate energy charge of the liver were investigated in rats having 16%, 50%, and 84% mortality rates after acute hemorrhage. In the arterial blood, concentrations of ketone bodies, pyruvate, lactate, and the ratios (acetoacetate to beta-hydroxybutyrate and pyruvate to lactate) were measured after hemorrhage and reinfusion of the shed blood. The mitochondrial oxido-reduction state and the blood ketone body ratio decreased 15 minutes after hemorrhage. The values of these parameters of rats having the higher mortality rate were lower than those rats having the lower mortality rate. In addition, the changes in both the adenylate energy charge and the mitochondria oxido-reduction state of the liver were closely correlated with the changes in the ratio of acetoacetate to beta-hydroxybutyrate in the arterial blood (P less than 0.001). Thus, it is suggested that the decreased oxygen supply to the liver mitochondria may play an important role in determining the mortality rate after acute hemorrhage and is reflected in the ratio of acetoacetate to beta-hydroxybutyrate in the arterial blood.

Acute Disease↗
PubMed1980

Combined effects of alcohol and sleep deprivation in normal young adults.

The effect of combining sleep deprivation and moderate alcohol consumption in male college students differed from the effects of each treatment alone. Following either alcohol or sleep deprivation, there was mild performance impairment, decreased alertness and reduced amplitude and increased latency of cortical evoked potential (EP) components. Heart rate increased after alcohol and anxiety increased after sleep deprivation. When alcohol and sleep deprivation were combined, antagonistic effects were found for most measures (reaction time, heart rate, alertness, anxiety, latency of early EP components), but synergistic effects also occurred (performance accuracy, latency of late EP components). These effects were found in a double-blind experiment using 24 subjects. The experimental treatments were alcohol doses of 0, 0.45 and 0.90 ml/kg of 95% ethanol and 0 and 26 h of sleep deprivation.

Adult↗
PubMed1980

Studies on Alternaria allergens. III. Isolation of a mafor allergenic fraction (ALT-I).

The allergens present in crude Alternaria alternata extract were fractionated by sequential ammonium sulfate precipitation, DEAE cellulose ion-exchange chromatography, preparative flat-bed electrofocusing, and Sephadex G-100 gel filtration. The carbohydrate-rich fraction isolated (Alt-I) was heterogeneous by polyacrylamide gel disc electrophoresis and by thin-layer electrofocusing. By preparative polyacrylamide gel electrophoresis the Alt-I fraction could be further separated into at least five subfractions, all of which contained similar allergenic activity. Significant elevations in IgE antibody to Alt-I were found in 21

Allergens↗
PubMed1980

Metabolic and psychophysiologic studies of cannabidiol-hexobarbital interaction.

Cannabidiol (CBD), 600 mg/day orally for 5 to 12 days, inhibited hexobarbital metabolism in ten subjects. Hexobarbital oral clearance was 36% lower and apparent volume of distribution was 35% smaller, with no change in half-life during CBD. In four subjects who received intravenous and oral hexobarbital, systemic clearance was 36% lower while bioavailability was 10% greater during CBD. Hexobarbital increased fatigue and tremor, impaired eye-tracking performance, and altered the electroencephalogram. Hexobarbital effects were not affected by CBD. Inhibition of metabolism of other drugs should be considered when large amounts of CBD are taken or when CBD is used for therapy.

Absorption↗
PubMed1980

Postnatal regulation of canine oxygen delivery: erythrocyte components affecting Hb function.

A rightward shift in the blood oxygen dissociation curve occurs during the 1st mo of canine life. A detailed peptide analysis indicated that dogs do not have a separate fetal hemoglobin. Other erythrocyte components such as ATP, K+, Na+, and H+ were excluded as significant mediators of the postnatal oxygen affinity change. Erythrocyte 2,3-DPG levels essentially zero in fetal dogs, increased rapidly during the 1st mo of canine life. There was a significant correlation between this postnatal 2,3-DPG increase and the postnatal decrease in blood oxygen affinity. Dialyzed hemolysates of fetal or adult canine blood have the same intrinsic oxygen affinity and the same response to normal adult levels of 2,3-DPG. Furthermore, the magnitude and direction of this 2,3-DPG-induced decrease in oxygen affinity in vitro are comparable to the in vivo postnatal change in oxygen affinity.

Aging↗
PubMed1980

Hemoglobin variants with altered oxygen affinity.

To date 88 abnormal hemoglobins have been described with altered oxygen affinities. Of these, 60 variants have high affinity and 28 have low affinity. Twenty-six of these abnormal hemoglobins are chemically unstable. Twenty-seven of the high affinity hemoglobins are associated with erythrocytosis. An equal number are not associated with increased red cell mass. Anemia has been reported with 13 of the low affinity variants; however, the primary cause of the anemia of many may be the concurrent chemical instability. A strong correlaton can be shown for stable variants with altered oxygen affinity between the P50 value of the red cell and the hemoglobin concentration of the affected individual's blood. Hemoglobin variants with altered oxygen affinity can be classified into groups depending upon the amino acid change in specific structural sites. The sites include subunit interfaces, heme contacts, central cavity, DPG binding site, C-terminus, and other external and internal residues. Functional studies of six abnormal hemoglobins, four at the beta 101 residue in the central cavity near the alpha 1 beta 2 interfce, one near the DPG binding site and one at the C-terminus of the beta chain, indicate that the exact explanation of the structure-function relationship in hemoglobin depends upon the specific residue that is altered and the chemical properties of the substituted group. Comparative studies of multiple variants of the same position should provide insight into the role of critical residues in the binding of oxygen by hemoglobin.

Binding Sites↗
PubMed1980

Application of anaerobic ion-exchange chromatography to the separation of hemoglobins in R from T conformational states.

As an allosteric protein, hemoglobin can assume at least two different quatenary structures, a deoxy or T for tense conformation and an oxy or R for relaxed conformation (2,3) depending upon its state of ligation. Because the pK values of oxy and deoxy- hemoglobins are different, molecules in the R conformation should behave differently than molecules in the T conformation on ion exchange chromatography. Kilmartin et al. (4) designed an anaerobic cation exchange chromatographic procedure with which they separated the deoxy hemoglobin from oxy hemoglobin and other R conformation hemoglobin components like CO-hemoglobin and sulfohemoglobin. In this report we describe the further development of Kilmartin's procedure to separate two electrophoretically silent hemoglobin mutants, Hb Potomac [beta 101 Glu leads to Asp] (5) a high oxygen affinity variant, and Hb M-Milwaukee [beta 67 Val leads to Glu] (6,8) a low oxygen affinity mutant from Hb A. The modifications we have made include (a) applying the hemolysate at a partial pressure of oxygen determined from an examination of the oxygen equilibrium curve to produce a favorable ratio of T to R conformations of the two hemoglobins to be separated, (b) controlling the partial pressure of oxygen tension of the column effluent during the development of the chromatogram.

Anaerobiosis↗