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R T Jones

Publications and source records attributed to R T Jones.

At least 19 recordsLinked to original sources
PubMed1992

Three-point cross-linking: potential red cell substitutes from the reaction of trimesoyl tris(methyl phosphate) with hemoglobin.

The symmetrical trifunctional cross-linking reagent trimesoyl tris(methyl phosphate) (3), reacts selectively with amino groups (beta 1Val and beta 82Lys) in the diphosphoglycerate binding site of human hemoglobin A, producing cross-linked tetrameric species in good yield. A major species is triply linked, alpha alpha beta 1(82) greater than B beta 82, where B symbolizes benzene-1,3,5-tricarbonyl. Both this triply linked species and the doubly linked species, alpha alpha beta 1B beta 82, produced from deoxyhemoglobin have a considerably lower oxygen affinity than does native hemoglobin while maintaining a high degree of cooperativity (n50 = 2.4), making them potentially useful as red cell substitutes, in principle delivering twice as much oxygen as whole blood between pO2 = 100 and = 40 Torr. The yield of products indicates that triply and doubly linked species form in parallel so that there are independent routes to each. It is proposed that differences in routes are due to stereoisomerism about the amide bonds which form from reaction of the reagent with the protein.

Amino Acid Sequence↗
PubMed1992

Regulation of protein degradation in normal and transformed human bronchial epithelial cells in culture.

Protein degradation rates are decreased in some transformed cells of mesenchymal origin. We have tested the generality of this phenomenon and evaluated the role of the lysosomes in this down-regulation. To this end we have compared the induction of lysosomal protein degradation among normal, transformed (BEAS-2B), and transformed tumorigenic (BZR, Calu-1) human bronchial epithelial cells in culture. Serum and/or nutrient deprivation, cell confluency, and Ca2+ were used to modulate lysosomal protein degradation. Protein degradation and synthesis were determined by the release or incorporation of [14C]valine in the cells. Autophagic degradation of cytoplasm by lysosomes was evaluated by ultrastructural morphometry. Basal protein degradation was lower (27%) in two of the transformed cell lines (BEAS-2B and BZR). Incorporation of [14C]valine label was raised approximately 4-fold in the transformed cells. Nutrient deprivation stimulated protein degradation equally (2-fold) in transformed and normal cells. Postconfluency increased (1.5-fold) basal protein degradation in Calu-1 cells and a marked enhancement (4-fold) of degradation occurred during nutrient deprivation. Culture of normal human bronchial epithelial cells in high Ca2+ caused phenotypic changes and increased (30%) the degradation of protein induced by nutrient deprivation. In Calu-1, high Ca2+ caused only phenotypic changes. The volume density (Vd) of autophagic vacuoles and dense bodies in the transformed cells was lower under basal conditions but increased markedly during nutrient deprivation. A marked accumulation of lysosomes also occurred in transformed cells during postconfluency. We conclude that cell transformation lowers basal protein degradation in some human epithelial cells. Lysosomal proteolysis of transformed cells is not down-regulated and can be markedly enhanced during nutritional deprivation by the autophagic degradation pathway.

Analysis of Variance↗
PubMed1992

Comparison of diagnostic procedures for porcine leptospirosis.

Kidneys and matched serum samples were obtained from 368 pigs slaughtered at three Victorian abattoirs, and originating from 42 farms. Macroscopic lesions (white spots) were observed on 102 of the kidneys. Serum samples were tested by the microscopic agglutination test (MAT) and by an IgM enzyme immunoassay (EIA). Kidneys were cultured for leptospires, examined histologically after Warthin-Starry silver staining and after immunogold silver staining (IGSS), and tested for leptospiral DNA by DNA hybridization. Forty-four infected pigs were identified by culture or immunogold silver staining of kidneys or by high MAT titres (greater than or equal to 1024). Infection was demonstrated in 7.5% of visibly normal kidneys, in 23.5% of kidneys with white spots, and in 48% of kidneys with large white spots, of 1 cm diameter or greater. The apparent (maximum) sensitivities of diagnostic procedures for detecting infection were as follows: MAT (at a titre of either 64 or 1024) 95%; IgM EIA 82%; culture 61%; presence of white spots 55%; IGSS 52%; presence of large white spots 30%; Warthin-Starry silver staining 20%. IGSS, Warthin-Starry staining and DNA hybridization all appeared to be highly specific. Of 22 kidney sections identified as positive by IGSS, 13 showed intact leptospires, and these kidneys were all culture-positive. Nine others showed leptospiral antigen in the kidney tubules but no intact leptospires. Only five of these kidneys were culture-positive.

Abattoirs↗
PubMed1992

Allergic reactions to latex among health-care workers.

With the emergence of the acquired immunodeficiency syndrome (AIDS) epidemic and the practice of protecting health-care workers from all body fluids, the use of rubber gloves has increased, as has occupational allergy to latex among health-care workers. During 1991, 49 Mayo Medical Center employees sought assessment and treatment of rhinitis, conjunctivitis, contact urticaria, contact dermatitis, asthma, or eczema thought to be related to exposure to latex. Most of these persons had a history of atopy and worked in areas where rubber gloves were used and changed frequently. Of the 49 subjects, 34 had positive results of skin tests to latex products, and the sera from 19 of 35 persons tested contained increased latex-specific IgE antibodies. Employees with sensitivity to latex (and co-workers in the immediate areas) should use vinyl gloves and should notify their own health-care providers of their sensitization. Changes in job assignment may be necessary for some persons.

Asthma↗
PubMed1992

Anaphylaxis in a milk-allergic child after ingestion of milk-contaminated kosher-pareve-labeled "dairy-free" dessert.

Milk-allergic persons often rely on kosher labeling to select dairy-free foods. A 2-year-old boy experienced multiple generalized reactions after ingestion of milk or milk products; his serum contained elevated levels of milk-specific IgE antibodies, and his milk skin test was strongly positive. An identical reaction occurred after ingestion of "pareve"-labeled raspberry sorbet. Using an inhibition immunoassay with pooled sera from two milk-sensitive persons as the source of IgE antibodies, we found the milk allergen level in sorbet provided by the family to be 11% of the level found in non-fat dry milk. The milk allergen level in three independently purchased containers of sorbet ranged from 2% to undetectable. The presence of milk in three of four of the sorbets was confirmed by immunoblotting studies, by quantitation of milk proteins by polyacrylamide gel electrophoresis, and by quantitation of lactose by gas chromatography. Subsequently, it was discovered that milk was incorporated into the sorbet when equipment used to package ice cream had been used to package the sorbet. Although kosher labeling may provide assurance to milk-sensitive persons that a particular food does or does not contain milk, such labeling is no guarantee that this is indeed the case.

Anaphylaxis↗
PubMed1992

Alternative strategies.

Drug treatment alternatives in the United States are constrained by what is politically correct and expedient and by a federal policy of 'zero tolerance' for any illicit psychoactive drug use. A war on drugs will not solve all the problems posed by cocaine. Alternative strategies must address fundamental problems in ghetto life: violence, poverty, poor health, no education, no jobs, and few reasons for not taking drugs. Despite warnings of pharmacological determinism, cocaine is like other psychoactive drugs. Even with cocaine, when alternative behaviours are possible most people avoid out-of-control use. Public health strategies promoting a harm-reduction policy offer advantages. Recent reductions in cocaine use are a consequence of education, awareness of good health practices, and interest in other activities. Alternatives could include cocaine in a safer, non-lethal and controllable form but are unlikely in a political climate where politics and law prevail rather than medicine and humanity.

Cocaine↗
PubMed1991

Disulfide bonding controls the processing of retroviral envelope glycoproteins.

The mitogenic membrane glycoprotein (gp55) encoded by Friend erythroleukemia virus is inefficiently processed from the rough endoplasmic reticulum (RER) and only 3-5% reaches plasma membranes. Because this processed component (gp55P) contains larger and more complex oligosaccharides, it can be separated from RER gp55. In nonreducing conditions, gp55P is a unique disulfide-bonded dimer, whereas RER gp55 consists of monomers and dimers with diverse intrachain and interchain disulfide bonds. This suggests that gp55 folds heterogeneously and that only one homodimer is competent for export from the RER. Pulse-chase analyses of gp55 components labeled with radioactive amino acids indicated that formation of diverse disulfide-bonded components occurred within minutes of polypeptide synthesis and that malfolded components did not later isomerize to generate dimers competent for export from the RER. Chemical studies suggested that all 12 cysteines of gp55 were oxidized within 5 min after synthesis of the protein. In contrast, the envelope glycoprotein precursor (gPr90) encoded by a replication-competent murine leukemia virus folds more homogeneously, and it is then processed and cleaved to form an extracellular glycoprotein gp70 plus a transmembrane protein p15E. The fully processed glycoprotein contains an unoxidized cysteine sulfhydryl that isomerizes reversibly with a disulfide bond that links gp70 to p15E. Consequently, only a proportion of gp70 and p15E is disulfide-bonded, and dissociation occurs when the environment becomes even slightly reducing. The gp55 glycoprotein appears to be an extreme example of protein malfolding associated with imprecise and irreversible disulfide bonding. We discuss evidence that folding inefficiencies are common for retroviral proteins that have newly evolving pathogenic functions.

Blotting, Western↗
PubMed1991

Human bronchial epithelial cells transformed by the c-raf-1 and c-myc protooncogenes induce multidifferentiated carcinomas in nude mice: a model for lung carcinogenesis.

We have previously described the neoplastic transformation of immortalized human bronchial epithelial cells (BEAS-2B) by the combination of the c-raf-1 and c-myc protooncogenes and the concomitant induction of neuron-specific enolase mRNA expression (A. Pfeifer et al., Proc. Natl. Acad. Sci. USA, 86: 10075-10079, 1989). In this paper we describe the morphological, biochemical, and immunohistochemical characteristics of the primary c-raf-1/c-myc tumors, xenografts of these tumors, and tumors that originated from cell lines of the primary neoplasm. The tumors were morphologically characterized by the appearance of desmosomes and tonofilaments, microvilli, and dense core granules representing markers of squamous, glandular, and neuroendocrine differentiation, respectively. A total of 11 of 13 tumors were positive by immunohistochemical techniques for neuron-specific enolase, serotonin (nine of 13), and calcitonin (six of 13). Keratins were expressed in 11 of 13 tumors, and while specific keratins (K5, K7, K16/K17) decreased, there was an increase of vimentin in the tumor cells. Gastrin-releasing peptide immunoreactivity was detectable in a small number of tumors (five of 13). BEAS-2B cells transfected with the c-raf-1 and c-myc protooncogenes and cell lines established from the primary tumors expressed major histocompatibility Class II antigen which has been found on small cell lung carcinoma cells. The tumors induced by the c-raf-1 and c-myc protooncogenes resemble the multidifferentiated phenotype of small cell lung cancer frequently detected in vivo and present a defined model to study the relation between molecular markers, phenotypical appearance, and response to chemotherapeutic agents and radiation.

Adenocarcinoma↗
PubMed1991

Concerted evolution led to high expression of a prosimian primate delta globin gene locus.

The delta globin gene in simian primates is either weakly expressed (in hominoids and New World monkeys) or silent (in Old World monkeys). In prosimian primates, however, an unequal homologous crossover between the psi eta and delta loci of lemurs produced a hybrid psi eta delta pseudogene locus, whereas in tarsier the delta locus encodes a beta-type chain found in 18% of adult tarsier hemoglobin molecules. In the present study, the nucleotide and amino acid sequences of the galago delta and beta globin genes and their encoded peptides were determined, and evidence is provided showing that the galago delta locus encodes a beta-type chain (beta 2) found in 40% of the galago fetal and postnatal hemoglobin molecules, whereas the beta locus encodes the remaining 60% of the beta-type chain (beta 1). Galago beta 1 and beta 2 chains differ from each other by only one amino acid residue. The homology between the galago delta and beta loci extends from 800 base pairs 5' of the proximal CCAAT element to near the end of exon 3 as a result of a recombination event in which beta sequence replaced delta sequence. After this initial recombination event, concerted evolution between the loci continued over their conserved coding, intron 1, and promoter regions but failed to occur between the two loci in their intron 2 and distal 5'-flanking sequences where the two loci have now diverged by 20%. Calculations based on this divergence value and on a rate of noncoding sequence evolution of 4.2 x 10(-9) to 5.5 x 10(-9) substitutions/site/year for the lorisiform lineage to galago yielded a date of 18-24 million years ago for the initial recombination event. The fact that the promoter sequences of the galago delta locus are the same as that of the galago beta locus may account for the high level of expression of the galago delta gene.

Amino Acid Sequence↗
PubMed1991

Methods for improving tissue culture of human tracheo-bronchial epithelium obtained at autopsy.

Human tracheo-bronchial epithelium obtained from autopsy, surgery, and organ donation will have areas of both viable and non-viable cells. It is important in the initial establishment of epithelial explant and cell cultures that injured, non-viable mucosal epithelium not be used for the cultures. Autopsy cases selected for culture should initially be chosen on the basis of a shorter post mortem interval and cause of death in order to increase the rate of successful culture. Staining the epithelium with the vital dye, trypan blue, in combination with phase contrast microscopy of the bronchial tissues will further identify those areas of the mucosa that are enriched for viable cells. The dead, non-viable areas are trypan blue positive, while the viable areas are clear and have foci of beating, motile cilia. Treatment of the mucosal tissue with mucolytic agents to remove cell debris, dead cells, and microbes trapped in the mucus material will further improve the chances for successful culture. Human tracheo-bronchial epithelium, although non-sterile and often injured at time zero for numerous reasons, can effectively be used in vitro pathophysiology studies.

Aryl Hydrocarbon Hydroxylases↗
PubMed1991

Using LabVIEW to facilitate calibration and verification for respiratory impedance plethysmography.

A system for calibrating the Respitrace impedance plethysmograph was developed with the capacity to quantitatively verify the accuracy of calibration. LabVIEW software was used on a Macintosh II computer to create a user-friendly environment, with the added benefit of reducing development time. The system developed enabled a research assistant to calibrate the Respitrace within 15 min while achieving an accuracy within the normally accepted 10% deviation when the Respitrace output is compared to a water spirometer standard. The system and methods described were successfully used in a study of 10 subjects smoking cigarettes containing marijuana or cocaine under four conditions, calibrating all subjects to 10% accuracy within 15 min.

Analog-Digital Conversion↗
PubMed1991

Hemoglobin Columbia Missouri or alpha 2[88 (F9) Ala----Val]beta 2: a new high-oxygen-affinity hemoglobin that causes erythrocytosis.

A previously undescribed hemoglobin variant, hemoglobin Columbia Missouri, alpha 88 (F9) Ala----Val, was detected in a 22-year-old white man who was undergoing assessment for erythrocytosis. This new hemoglobin variant does not separate from hemoglobin A by electrophoresis in conventional media, by isoelectric focusing, or by electrophoresis of purified globin chains in 8 M urea. It exhibits a high oxygen affinity, with a P50 (oxygen tension at 50% saturation) of 19.3 torr for the patient's whole blood. The substitution of hemoglobin Columbia Missouri is an internal residue near the end of the F helix of the alpha chain. Hemoglobin Okazaki has an arginyl residue substitution for a cysteinyl residue at F9 (beta 93) in the beta chain. In comparison with hemoglobin Okazaki, the substitution in hemoglobin Columbia Missouri has a more pronounced effect on oxygen affinity. Consequently, hemoglobin Columbia Missouri is associated with erythrocytosis, whereas hemoglobin Okazaki is not.

Adolescent↗
PubMed1991

Cell-to-cell communication: a differential response to TGF-beta in normal and transformed (BEAS-2B) human bronchial epithelial cells.

The effects of transforming growth factor beta (TGF-beta) on cell-to-cell communication were investigated in the log phase of growth in normal BE and in adenovirus-12 SV40 hybrid virus transformed BE cells (strain BEAS-2B). Gap junctions in these cells were identified immunocytochemically. Exposure of BE cells to exogenous TGF-beta (0.04-4.0 pM) in serum-free keratinocyte growth medium (KGM) for 1 or 24 h reduced the rate of fluorescent dye transfer (i.e. cell-to-cell communication) by 30-50% in BE cells. Inversely, in BEAS-2B cells, TGF-beta after 1 h induced a 2- to 10-fold increase in the rate of dye transfer. After 24 h of TGF-beta, communication among BEAS-2B cells was not significantly different from controls (no exogenous TGF-beta). The protein kinase C (PKC) inhibitor H-7 induced a dose-dependent enhancement in communication, which was even higher in the presence of TGF-beta (4 pM X 24 h). The calmodulin antagonist W-7 enhanced communication in BEAS-2B cells independently of the presence of TGF-beta. In keratinocyte basal medium (KBM) supplemented with EGF (5 ng/ml) or with TGF-beta (4.0 pM) dye transfer was reduced or enhanced respectively. The combination of EGF and TGF-beta in KBM antagonized the stimulatory effect of the latter on communication in BEAS-2B cells. In BE cells, continuous exposure (4 days) to TGF-beta in KGM induced a dose-dependent inhibition of proliferation and an increased expression of a keratinized, epidermoid phenotype. This correlated with a reduction in the expression of a mucous secretory phenotype. Increased exposure to TGF-beta (0.04-4.0 pM) decreased the labeling index in BEAS-2B cells, but the cells retained a growth advantage over normal BE cells, and did not express a keratinized epidermoid morphology. With respect to dye transfer as an index of cell-to-cell communication, we conclude (i) that an inhibition or enhancement of communication is involved in the response of bronchial epithelial cells to mitogens (e.g. epidermal growth factor) or growth inhibitors (e.g. TGF-beta), (ii) that PKC and Ca(2+)-calmodulin-dependent processes regulate dye transfer, and (iii) the effects of TGF-beta are mediated by PKC.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1991

Child, adolescent, and adult victims of residential fire. Psychosocial consequences.

Behavior of children, adolescents, and adults during and after a residential fire was objectively assessed. Antecedents, behaviors, and consequences of the nighttime residential fire immediately and 1 month following the fire were obtained. Also, the extent of agreement between children/adolescent and adult functioning was determined. Eight children and adolescents and 12 adults were individually interviewed. Results showed that individuals' reactions to residential fire could be assessed, and several PTSD-related symptoms were expressed. A follow-up study in which 25 adolescent boys whose dormitory had been totally destroyed by fire were compared to 13 boys who had not experienced the fire showed similar findings. These findings add to the dearth of literature concerning children and adolescents in fire-related disasters.

Adaptation, Psychological↗
PubMed1991

Serum prostatic acid phosphatase activity and prostate specific antigen when the prostate gland is enlarged.

Serum prostatic acid phosphatase activity and prostate specific antigen levels were measured in the serum of 113 patients undergoing transurethral resection of an enlarged prostate gland, and the results compared with the histological diagnosis. Prostate-specific antigen was found to be the more sensitive indicator of malignancy, but prostatic acid phosphatase was more specific.

Acid Phosphatase↗
PubMed1991

Laboratory investigation of deaths due to anaphylaxis.

To establish a useful laboratory protocol to investigate possible cases of fatal anaphylaxis, we measured mast-cell-derived tryptase levels and allergen-specific immunoglobulin E (IgE) antibody levels in sera obtained prior to or within 24 h after death from 19 anaphylaxis victims. Elevated serum tryptase levels (range = 12 ng/mL to 150 micrograms/mL) were found in nine of nine Hymenoptera sting fatalities, six of eight food-induced fatalities, and two of two reactions to diagnostic therapeutic agents. Tryptase levels were normal (less than 10 ng/mL) in 57 sequential sera obtained postmortem from six control patients. Tryptase could not be measured in pleural or pericardial fluids for technical reasons. Serum IgE antibodies were elevated in five of the nine Hymenoptera sting fatalities and in eight of the eight fatal food reactions; assays were unavailable for the two diagnostic/therapeutic agents. If elevated, the victim's serum IgE antibodies to food could be used to identify allergens in uneaten portions of foods consumed shortly before the anaphylactic event. IgE antibodies were moderately stable during storage in a variety of anticoagulants at room temperature for up to 11 weeks. Elevated mast-cell-derived tryptase levels in postmortem sera reflect antemortem mast cell activation and may be used as a marker for fatal anaphylaxis. If assays are available for IgE antibodies to relevant allergens, such assays provide evidence for antemortem sensitization; these assays may be modified to identify allergens in foods consumed by victims of food-induced anaphylaxis.

Aged↗