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Biomedical subjects

R T Jones

Publications and source records attributed to R T Jones.

At least 109 records · Page 6Linked to original sources
PubMed1990

Biochemical and immunochemical comparison of Africanized and European honeybee venoms.

Africanized honeybees (HBs) pose a hazard to both normal and sting-sensitive subjects in certain areas of Central and South America, and it is predicted that they will soon be present in the southern United States as well. Using an electrical stimulation device, we collected Africanized HB venom (AHV) in Venezuela and European HB venom (EHV) in Louisiana. These venoms, along with commercial European HB venom (CHV), were compared by thin-layer isoelectric focusing and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The Coomassie brilliant blue and silver-stained banding patterns of AHV and EHV were essentially identical to CHV. Western blots were prepared from SDS-PAGE gels and tested with pooled sera from EHV-sensitive subjects and then radiolabeled antihuman IgE. The resulting autoradiographs revealed similar banding patterns among EHV, AHV, and CHV. RAST-inhibition studies were performed with solid-phase CHV and pooled sera from EHV-sensitive subjects. The specific allergenic activities of the three HB venoms (allergy units per milligram of protein) were comparable. By RAST-inhibition assay with solid-phase, highly purified individual venom components, AHV and EHV both contained phospholipase A2, hyaluronidase, and high-molecular-weight allergens. The increased morbidity after Africanized HB stings is likely related to their more defensive behavior during which many bees react by stinging rather than to biochemical or allergenic differences between AHV and EHV.

Allergens↗
PubMed1990

Two families with hemoglobin Sogn, beta(A11)14 Leu----Arg, in Minnesota and Indiana: hematologic, functional, and biosynthetic features.

Sogn hemoglobinopathy was identified in a young American woman and in a young American man of apparently unrelated families of Norwegian ancestry. Both persons were asymptomatic and without clinical or hematologic manifestations. Hemoglobin Sogn, beta(A11)14 Leu----Arg, is an unstable hemoglobin that may easily be mistaken for hemoglobin S, G, or D by alkaline hemoglobin electrophoresis. These are the first known instances of hemoglobin Sogn outside of Norway. Oxygen affinity is normal. Sogn hemoglobinopathy is an incidental finding that has no adverse implication for the health of heterozygotes.

Adult↗
PubMed1990

Immunoassay of peanut allergens in food-processing materials and finished foods.

To quantitate trace amounts of peanut allergens in food-processing materials and finished foods, we established a solid-phase radioimmunoassay inhibition using pooled sera from five peanut-sensitive subjects and a roasted peanut-meal extract covalently linked to polyacrylamide beads. Test samples were extracted, dialyzed, lyophilized, and reconstituted at 10 to 225 mg of dry weight per milliliter concentrations. The peanut-allergen content of test samples was expressed relative to a reference extract of roasted peanut meal that was assigned an arbitrary potency of 100,000 U/ml. In confectionery products spiked with varying quantities of peanut (0.7% to 0.0175%), the recovery of peanut allergen ranged from 31% to 94%. The sensitivity of the assay was 2.5 U/mg of dry weight from these samples (0.00875% peanut). Peanut allergens were undetectable in virgin vegetable oil used to roast peanuts, but 600 to 7600 U/mg of dry weight were present in oil after varying periods of use. The allergen content of used oil was reduced to 8 U/mg of dry weight by filtration and steam cleaning. The availability of such assays provides a means of monitoring finished food products for potential allergens. This monitoring in turn will provide the means to correlate symptoms experienced by sensitive patients with the exact quantity of allergen ingested. At the present time, there is little information on the quantities of ingested peanut allergen that pose risks to peanut-sensitive subjects.

Allergens↗
PubMed1990

Effect of elaboration on the acquisition and maintenance of cardiopulmonary resuscitation.

Investigated the influence of training on the acquisition and retention of cardiopulmonary resuscitation (CPR) skills by 38 sixth-grade children. Three training methods were compared: precise elaboration, imprecise elaboration, and maintenance rehearsal. Each of these methods was coupled with behavioral training and compared to a no-treatment control condition. Three CPR situations were selected for training: breath and pulse present, breath absent/pulse present, and breath and pulse absent. Data were collected at pretest, posttest, and 1-, 3-, and 5-month follow-ups, the dependent variable responses occurring in sequence. Results indicated that children in the three treatment conditions acquired and maintained the CPR responses at a significantly higher level than the control group. Evidence for the potential superiority of the precise elaboration group over the other conditions was provided.

Child↗
PubMed1990

A primary preventive approach to children's drug refusal behavior: the impact of rehearsal-plus.

The effectiveness of a short-term prevention program to increase drug refusal behavior in a school-age population was assessed. Forty-two third-grade children were randomly assigned to one of three groups: rehearsal-plus, traditional, or attention control. Children in the rehearsal-plus group were taught specific drug refusal techniques and appropriate social skills, and were provided a rationale for each response. This procedure included behavioral training and elaborative rehearsal. Training occurred in four socially validated situations corresponding to settings where children were likely to be offered drugs. The traditional procedure consisted of instructions derived from a "Just Say No" drug program. Assessment focused on specific refusal behaviors, procedural knowledge, and self-efficacy. Significant gains in desired functioning and appropriate behavioral and social skills were found. The effectiveness of the rehearsal-plus procedure as a method of increasing adaptive responding in dangerous and/or anxiety-arousing situations is discussed.

Behavior Therapy↗
PubMed1990

Effect of growth temperature on folding of carbamoylphosphate synthetases of Salmonella typhimurium and a cold-sensitive derivative.

The properties of homogeneous preparations of carbamoylphosphate synthetase (CPSase) from wild-type Salmonella typhimurium and a cold-sensitive derivative grown at different growth temperatures were examined. For the cold-sensitive mutant, the affinity for glutamine of the form of CPSase synthesized at 20 degrees C was lower than that of the form of the enzyme synthesized at 37 degrees C, regardless of the assay temperature. Thus, the cold sensitivity of the mutant reflects an effect of temperature on the synthesis of the enzyme rather than the activity of the folded enzyme. The two forms also differed in sensitivities to polyclonal antibodies as well as denaturational enthalpies. The combined results support the hypothesis that carAB mutations conferring cold sensitivity identify amino acid residues that are critical in the folding of CPSase. Quite unexpectedly, certain kinetic properties of cloned parent CPSase were also dependent on the growth temperature, although to a much lesser extent than those of the cold-sensitive mutant. The specific activity of wild-type CPSase synthesized at 15 degrees C was 60% of that synthesized at 37 degrees C. Further, CPSase synthesized at 15 degrees C was less thermostable than the enzyme synthesized at 37 degrees C; the difference in stability (delta G) is estimated to be 4,500 cal mol-1. Thus, variation of temperature within the physiological range for growth influences the folding and consequently the properties of CPSase from wild-type S. typhimurium.

Ammonium Chloride↗
PubMed1990

Shared allergenic activity in Asian (Blattella asahinai), German (Blattella germanica), American (Periplaneta americana), and Oriental (Blatta orientalis) cockroach species.

Whole-body extracts of the feral and peridomestic Asian cockroach (Blattella asahinai) and the three domestic cockroach species, German (Blattella germanica), American (Periplaneta americana), and Oriental (Blatta orientalis), were compared allergenically using an IgE serum pool from 4 German cockroach sensitive individuals. In crossover radioallergosorbent inhibition analysis, the Asian cockroach shared allergenic activity primarily with the German cockroach polymer and to a lesser extent with either the American or Oriental cockroach polymers. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and thin-layer isoelectric focusing analysis of the extracts showed similar although varying intensities of Coomassie blue stained banding patterns among five extracts analyzed. Electroblotting analysis with 12.5% SDS-PAGE of the whole-body German cockroach extract and IgE serum from individuals sensitive to German cockroach revealed eight allergenic components with apparent molecular weights of 92, 80, 67, 48, 36, 27, 25 and 18 kD. Five components could be identified in the whole-body extract of the Asian cockroach corresponding to apparent molecular weights of 92, 67, 48, 40, and 32 kD. Analysis of individual serum by immunoblot analysis with each of the cockroach extracts showed considerable heterogenicity in the IgE-binding pattern. Although the Asian cockroach demonstrated considerable cross-reacting allergenic components to German and relatively fewer cross-reacting allergenic components to either the Oriental or American, it is too early to establish genus- or species-specific cockroach allergens. It is important to point out that German cockroach sensitive individuals should be made aware of the potential exposure of Asian cockroach aeroallergens both indoors and outdoors in areas with high infestations of Asian cockroaches.

Allergens↗
PubMed1990

Intercellular communication in bronchial epithelial cells: review of evidence for a possible role in lung carcinogenesis.

A challenging aspect of lung carcinogenesis is the elucidation of the mechanisms which permit initiated bronchial epithelial cells to attain a growth advantage over normal bronchial epithelial cells, and subsequently evolve into a malignant phenotype. In this review, the effects of interactions between normal and transformed cells, and the potential role of representative extrinsic factors on cell-cell communication are discussed. Evidence is presented to show how cell injury and the effects of serum and calcium may affect morphology and communication, and tumor development. A large number of autocrine-paracrine factors (e.g., TGF beta, TGF alpha) are released by bronchial epithelial cells. These factors may inhibit or promote the proliferation of normal and transformed bronchial epithelial cells, respectively. The ability of certain injurious and tumor promoting agents (e.g., formaldehyde, TPA) to select for the transformed phenotype may involve selective cell injury, the induction of terminal differentiation and an inhibition of gap junction communication among normal BE cells.

Bronchi↗
PubMed1990

Hb Johnstown [beta 109 (G11) Val----Leu]: a new electrophoretically silent variant that causes erythrocytosis.

A high oxygen affinity hemoglobin, previously undescribed, was found in a healthy, asymptomatic patient with mild erythrocytosis and left-shifted hemoglobin-O2 dissociation curve. The hemoglobin variant could not be distinguished from Hb A by any of several electrophoretic methods nor by ion exchange chromatography. It was separated and analyzed by reversed phase high performance liquid chromatography. Structural analysis revealed the substitution beta 109 (G11) Val----Leu. The variant was named Hb Johnstown. The amino acid substitution perhaps disrupts alpha 1 beta 1 contacts in the deoxyhemoglobin conformation, thus shifting the equilibrium towards the high affinity oxyhemoglobin conformation.

Adult↗
PubMed1989

Structure and function of human hemoglobin covalently labeled with periodate-oxidized adenosine triphosphate.

Periodate-oxidized adenosine triphosphate (o-ATP), a ribose ring-opened dialdehyde derivative of ATP, reacts specifically with human deoxyhemoglobin to give a single major covalently modified product after reduction with sodium borohydride. This product, designated di-ATP Hb, was isolated using ion-exchange chromatography and shown to have incorporated two molecules of o-ATP/tetramer. Peptide mapping and x-ray crystallography at 2.8-A resolution indicate that a covalent adduct is formed between the ligand and residues Lys-82 EF6 of each beta chain in the organic phosphate-binding site of the molecule. di-ATP Hb exhibits a significantly decreased oxygen affinity (P50 = 20.8 mm Hg versus 5.8 mm Hg control; 50 mM 2-[bis(2-hydroxyethyl)amino]-2-(hydroxymethyl)-propane-1,3-diol, pH 7.4, 0.1 M C, 20 degrees C). The subunit cooper-activity of di-ATP Hb is also reduced (nmax = 1.9 versus 2.7 control).

Adenosine Triphosphate↗
PubMed1989

Electrocardiographic and hemodynamic effects of intravenous cocaine in awake and anesthetized dogs.

Graded bolus and infusion doses of cocaine were given to 18 dogs, 6 under general anesthesia and 12 awake, to determine the range of hemodynamic and electrocardiographic effects. Blood pressure, electrocardiographic measurements, cocaine plasma levels, temperature, electrolytes, and arterial blood gases were measured before and after the initial bolus and/or infusion at 10 minutes and each 30 minutes up to a maximum of 180 minutes. At the end of the infusion, a single large intravenous terminal bolus of cocaine was given. The hemodynamic and electrocardiographic changes occurred by 10 minutes after the bolus and resolved by 30 minutes, independent of the infusion rate and dose. Only anesthetized dogs could tolerate the highest cocaine doses. Three ranges of bolus doses were given: the lowest range was the average initial bolus dose received by the awake group; the intermediate range was the average initial bolus dose received by the anesthetized group; and the highest range was the average terminal bolus dose. The heart rate changes were unpredictable and did not change significantly at any dose range. The blood pressure increased in the lowest dose range, remained unchanged at intermediate doses, and fell at the highest doses in four of six dogs. Electrocardiographic intervals increased as the dose range increased. Only at the highest doses did potentially lethal ventricular arrhythmia (ventricular tachycardia and an idioventricular escape rhythm) occur. Intravenous cocaine causes hemodynamic and electrocardiographic effects that are related to the dose and rate of administration. At high doses, hypotension, arrhythmia, and electrocardiographic changes consistent with infranodal and/or intraventricular conduction slowing can occur.

Anesthesia, General↗
PubMed1989

Electrophysiologic effects of cocaine on the canine ventricle.

To evaluate the electrophysiologic effects of cocaine on the ventricle, 12 conscious dogs were studied before and after a bolus and infusion of cocaine titrated to maximum tolerance or to an increase in the mean blood pressure by at least 15%. Plasma cocaine levels, blood pressure, and surface and intracardiac electrograms were recorded. Programmed electrical stimulation was performed from the right ventricle at drive cycle lengths of 400 and 350 ms with introduction of up to three extrastimuli. The right ventricular effective refractory period decreased by 10% (p less than or equal to 0.01) and the mean blood pressure increased by 19% (p less than or equal to 0.01). No sustained spontaneous or induced ventricular arrhythmias were recorded after cocaine administration. There were no significant changes in pacing threshold, intraventricular conduction, heart rate, QRS or QTc intervals. The cocaine dose infused was 2.1 +/- 1.0 mg/kg; cocaine plasma levels were 1969 +/- 959 ng/ml immediately after the bolus and 508 +/- 234 ng/ml at the end of the study. It is concluded that in a presumably normal canine heart and at the doses given that cocaine decreases right ventricular effective refractory period, does not change intraventricular conduction, and does not result in sustained spontaneous or induced ventricular arrhythmias.

Animals↗
PubMed1989

Leptospira interrogans serovar hardjo is not a major cause of bovine abortion in Victoria.

The aim of this study was to determine whether evidence could be obtained of foetal infection with Leptospira interrogans serovar hardjo in aborted foetuses collected from dairy farms. Material from 197 abortions occurring over a wide area of Victoria was collected over 3 years. None of 195 foetal kidney cultures or 7 cultures from membranes was positive for leptospiral organisms. Immunogold silver staining for leptospires was performed on sections of kidneys, lungs or heart from 156 foetuses, with negative results. Evidence of transient leptospiral infection in 11 of 123 foetuses was obtained by foetal heart blood serology. Two isolates of L. interrogans serovar hardjo were obtained from the urine of milking cows. These strains were examined by restriction endonuclease analysis and both were shown to be of the genotype Hardjobovis, as have been all Australian isolates studied so far. It appears that foetal infection with serovar hardjo is not associated with any substantial proportion of bovine abortions in Victoria, in contrast to the situation in Northern Ireland. The apparent absence from Victoria of the pathogenic genotype Hardjoprajitno is a possible explanation.

Abortion, Veterinary↗
PubMed1989

Mutant fetal hemoglobin causing cyanosis in a newborn.

A well but cyanotic newborn was found to have a mutant gamma-globin chain, leading to a functionally abnormal fetal hemoglobin. A single amino acid substitution was found in a site consistent with known adult M hemoglobins. This patient showed no clinical evidence of cyanosis at 5 weeks of age as gamma-chain synthesis was replaced by beta-chain synthesis. A sibling born 20 months later was also cyanotic and the same mutant hemoglobin was found.

Cyanosis↗
PubMed1989

Detection of leptospires in pig kidney using DNA hybridisation.

DNA hybridisation detected leptospiral organisms in homogenised kidneys from experimentally infected pigs, and in homogenates of pig kidneys collected at abattoirs. The technique is easy to perform and had some advantages over cultural and histological methods, in permitting the rapid survey of many kidneys simultaneously. Leptospires added to a homogenate of uninfected kidney could be detected at 10(2) organisms ml-1 by DNA hybridisation, but the technique appeared to be less sensitive than culture.

Abattoirs↗