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Biomedical subjects

M Fay

Publications and source records attributed to M Fay.

At least 19 recordsLinked to original sources
PubMed2000

The mitogen-activated protein kinase extracellular signal-regulated kinase 1/2 pathway is involved in formyl-methionyl-leucyl-phenylalanine-induced p47phox phosphorylation in human neutrophils.

Phosphorylation of p47 phagocyte oxidase, (p47(phox)), one of the NADPH oxidase components, is essential for the activation of this enzyme and for superoxide production. p47(phox) is phosphorylated on multiple serine residues, but the kinases involved in this process in vivo remain to be characterized. We examined the role of extracellular signal-regulated kinase (ERK1/2) and p38 mitogen-activated protein kinase in p47(phox) phosphorylation. Inhibition of ERK1/2 activation by PD98059, a specific inhibitor of ERK kinase 1/2, inhibited the fMLP-induced phosphorylation of p47(phox). However, PD98059 weakly affected PMA-induced p47(phox) phosphorylation, even though ERK1/2 activation was abrogated. This effect was confirmed using U0126, a second ERK kinase inhibitor. Unlike PD98059 and U0126, the p38 mitogen-activated protein kinase inhibitor SB203580 did not inhibit the phosphorylation of p47(phox) induced either by fMLP or by PMA. Two-dimensional phosphopeptide mapping analysis showed that, in fMLP-induced p47(phox) phosphorylation, PD98059 affected the phosphorylation of all the major phosphopeptides, suggesting that ERK1/2 may regulate p47(phox) phosphorylation either directly or indirectly via other kinases. In PMA-induced p47(phox) phosphorylation, GF109203X, a protein kinase C inhibitor, strongly inhibits p47(phox) phosphorylation. However, in fMLP-induced p47(phox) phosphorylation, PD98059 and GF109203X partially inhibited the phosphorylation of p47(phox) when tested alone, and exerted additive inhibitory effects on p47(phox) phosphorylation when tested together. These results show for the first time that the ERK1/2 pathway participates in the phosphorylation of p47(phox). Furthermore, they strongly suggest that p47(phox) is targeted by several kinase cascades in intact neutrophils activated by fMLP and is therefore a converging point for ERK1/2 and protein kinase C.

Butadienes↗
PubMed2000

Effect of case managers with a general medical patient population.

The objectives of this study were to evaluate the effect of inpatient case management (CM) on a general medical service and to determine if a prediction rule, identifying patients likely to need discharge planning services, could define a subset of patients for whom CM would be most effective. We hypothesized that CM would have greatest impact on patients predicted to be at highest risk of needing discharge planning to arrange for post-discharge medical services. We carried out a prospective controlled study. Six general medicine teams from a 600-bed urban teaching hospital were randomly assigned to CM (n = 4) or standard care (SC) (n = 2). Number of patients = 302 (207 CM; 95 SC). Case managers participated in daily physician team rounds and coordinated discharge planning for CM patients; SC patients received discharge planning from staff nurses or discharge planners when requested by physicians. The outcomes measured were deviation from the hospital length of stay (LOS) expected for a patient's diagnosis, patient satisfaction and non-acute medical service utilization during the month after discharge. Overall, patients from CM and SC teams did not differ in their deviation from expected LOS, post-discharge medical service utilization and patient satisfaction. However, after stratifying patients by their predicted need for post-discharge medical services, only patients in the 'high risk' category had a significantly shorter LOS under CM (2.9 days shorter than SC patients; P = 0.02). We concluded that, in this study, the effect of case managers on a general medical service was limited to shortening LOS only among a stratum of high risk patients.

Adult↗
PubMed2000

Maximal and partial expiratory flow rates in a population sample of 10- to 11-yr-old schoolchildren. Effect of volume history and relation to asthma and maternal smoking.

The effect of volume history on forced expiratory flow rates has been reported to differ between patients with asthma and healthy persons, and it has been hypothesized that the peripheral airway inflammation of patients with asthma may underlie this difference. There are no published data, however, on the distribution of such volume history effects or the relation of these effects to airways disease in children. We obtained combined partial and maximal forced expiratory flow-volume curves on 1,834 children, age 10-11 yr, in eight communities in the United States and Canada. The effect of a deep inhalation on forced expiratory flow rates at low lung volumes was quantitated by the ratio of V (30) during a maximal expiratory maneuver (V (30M)) to V (30) during a partial expiratory maneuver (V (30P)). The V (30M)/V (30P) ratio was slightly higher among girls than boys (1.26 versus 1.18, p = 0.0001) indicating that a deep inhalation increased V (30) slightly more among girls than among boys. The V (30M)/V (30P) ratio was related to neither history of asthma nor to maternal smoking. In contrast, most spirometric indices from either the maximal or the partial expiratory flow-volume curve were lower in association with a history of asthma or a report of maternal smoking. The ratio of FEF(25-75)/FVC was particularly consistent as a measurement that discriminated both of these effects in boys and girls. These results suggest that the measurement of volume history effects offers no benefits for epidemiological studies of childhood respiratory disease whereas spirometric indices such as the FEF(25-75)/FVC ratio are quite sensitive to the effects of asthma and environmental tobacco smoke exposure on the airways.

Asthma↗
PubMed1999

Vasopressin stimulates long-term net chloride secretion in cortical collecting duct cells.

The classical short-term effect (within minutes) of arginine vasopressin (AVP) consists in increasing sodium, chloride and water transport in kidney cells. More recently, long-term actions (several hours) of the hormone have been evidenced on water and sodium fluxes, due to transcriptional enhancement in the expression of their transporters. The present study demonstrates that AVP is also responsible for a long-term increase in net chloride secretion. In the RCCD(1) rat cortical collecting duct cell line, 10(-8) M AVP induced, after several hours, an increase in net (36)Cl(-) secretion. This delayed effect of AVP was inhibited by basal addition of 10(-4) M bumetanide and apical addition of 10(-4) M glibenclamide, suggesting chloride entry at the basal membrane through a Na(+)/K(+)/2Cl(-) and apical secretion through a chloride conductance. An original acute cell permeabilization method was developed to allow for entry of antibodies directed against the regulatory region (R) of the cystic fibrosis transmembrane regulator (CFTR) into the cells. This procedure led to a complete and specific blocking of the long-term net chloride secretion induced by AVP. Finally, it was observed that CFTR transcripts steady-state level was significantly increased by AVP treatment. Besides the well-documented short-term effect of AVP on chloride transport, these results provide evidence that in RCCD(1) cells, AVP induces a delayed increase in transepithelial net chloride secretion that is mediated by a Na(+)/K(+)/2Cl(-) co-transporter and CFTR.

Animals↗
PubMed1999

The majority of H2-M3 is retained intracellularly in a peptide-receptive state and traffics to the cell surface in the presence of N-formylated peptides.

We used a new monoclonal antibody (mAb 130) to analyze the intracellular trafficking and surface expression of H2-M3, the major histocompatibility complex class Ib molecule that presents N-formylated peptides to cytotoxic T cells. M3 surface expression is undetectable in most cell types due to the paucity of endogenous antigen. M3 is induced on the cell surface by addition of high-affinity N-formylated peptides from mitochondria and listeria. Peptide-induced M3 expression is most efficient on antigen presenting cells. Basal and inducible expression of M3 is transporter associated with antigen processing (TAP)-dependent, distinguishing M3 from the class Ib molecules TL and CD1. Unlike the expression of class Ia molecules and a previously described M3/L(d) chimera, surface expression of M3 cannot be rescued by lowered temperature, suggesting that the alpha3 domain and transmembrane region of M3 may control trafficking. Pulse-chase analysis and use of trafficking inhibitors revealed a pool of empty M3 in the endoplasmic reticulum or early Golgi apparatus. Addition of exogenous peptide allows maturation with kinetics matching those of D(d). The lack of endogenous N-formylated peptide allows discovery of novel pathogen-derived peptides in normal antigen presenting cells. The nonpolymorphic nature of M3 and its ability to present bacterial antigens rapidly and dominantly make it an attractive target for peptide vaccination strategies.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1999

Priming of human neutrophil respiratory burst by granulocyte/macrophage colony-stimulating factor (GM-CSF) involves partial phosphorylation of p47(phox).

Neutrophil superoxide production can be potentiated by prior exposure to "priming" agents such as granulocyte/macrophage colony stimulating factor (GM-CSF). Because the mechanism underlying GM-CSF-dependent priming is not understood, we investigated the effects of GM-CSF on the phosphorylation of the cytosolic NADPH oxidase components p47(phox) and p67(phox). Preincubation of neutrophils with GM-CSF alone increased the phosphorylation of p47(phox) but not that of p67(phox). Addition of formyl-methionyl-leucyl-phenylalanine (fMLP) to GM-CSF-pretreated neutrophils resulted in more intense phosphorylation of p47(phox) than with GM-CSF alone and fMLP alone. GM-CSF-induced p47(phox) phosphorylation was time- and concentration-dependent and ran parallel to the priming effect of GM-CSF on superoxide production. Two-dimensional tryptic peptide mapping of p47(phox) showed that GM-CSF induced phosphorylation of one major peptide. fMLP alone induced phosphorylation of several peptides, an effect enhanced by GM-CSF pretreatment. In contrast to fMLP and phorbol 12-myristate 13-acetate, GM-CSF-induced phosphorylation of p47(phox) was not inhibited by the protein kinase C inhibitor GF109203X. The protein-tyrosine kinase inhibitor genistein and the phosphatidylinositol 3-kinase inhibitor wortmannin inhibited the phosphorylation of p47(phox) induced by GM-CSF and by fMLP but not that induced by phorbol 12-myristate 13-acetate. GM-CSF alone did not induce p47(phox) or p67(phox) translocation to the membrane, but neutrophils treated consecutively with GM-CSF and fMLP showed an increase (compared with fMLP alone) in membrane translocation of p47(phox) and p67(phox). Taken together, these results show that the priming action of GM-CSF on the neutrophil respiratory burst involves partial phosphorylation of p47(phox) on specific serines and suggest the involvement of a priming pathway regulated by protein-tyrosine kinase and phosphatidylinositol 3-kinase.

Biological Transport↗
PubMed1999

P40phox associates with the neutrophil Triton X-100-insoluble cytoskeletal fraction and PMA-activated membrane skeleton: a comparative study with P67phox and P47phox.

NADPH oxidase is an O2*- -generating enzyme found in phagocytes such as neutrophils. It is composed of a membrane-bound cytochrome b, the cytosolic proteins p67phox, p47phox, p40phox, and the G-protein p21rac. The system is dormant in resting cells but acquires catalytic activity on exposure to appropriate stimuli. Cytochrome b, p67phox, p47phox, and rac2 associate with the cytoskeleton and membrane skeleton of activated neutrophils. It is not known whether p40phox associates with the cytoskeleton. The purpose of this study was to analyze the subcellular distribution of p40phox. When resting neutrophils were lysed in Triton X-100 or octyl glucoside buffer and separated into detergent-soluble and detergent-insoluble fractions, p40phox and p67phox were mainly associated with the detergent-insoluble fraction (defined as the cytoskeleton), whereas p47phox was mainly found in the soluble fraction. Neutrophil activation by phorbol myristate acetate (PMA) induced p47phox translocation to the cytoskeleton but did not affect the distribution of p40phox or p67phox. Using immunofluorescence confocal microscopy, we found that p40phox colocalized with filamentous actin. In neutrophils from a p67phox-deficient patient with detectable p40phox, p40phox associated with the cytoskeleton only after activation by PMA. A complex containing the three proteins was isolated from the cytoskeleton of activated neutrophils. When activated membranes were treated with Triton X-100 buffer, p40phox, p47phox, and p67phox were found in the membrane skeleton enriched in NADPH-oxidase activity; some p40phox and p47phox was found in the soluble membrane fraction, but no p67phox was detected. These findings show that p40phox, like p67phox and p47phox, binds to the cytoskeleton and membrane skeleton. In addition, p40phox can dissociate from p67phox in activated membranes.

Actins↗
PubMed1999

Defective priming of the phagocyte oxidative burst in a child with recurrent intracellular infections.

Human phagocytes (polymorphonuclear neutrophils and monocytes) play a critical role in host defense against invading microorganisms. Recent studies reported that circulating phagocytes undergo a final maturation process, in particular in terms of oxidative burst, during extravasation and migration to local sites of inflammation. This process is known as priming. We report here on a nine-year-old boy with successive disseminated infections due to intracellular microorganisms (Mycobacterium bovis, BCG, and Salmonella typhimurium). No T- or B-cell quantitative or qualitative defects were found. Polymorphonuclear neutrophil (PMN) migration and NADPH oxidase in PMNs and monocytes stimulated with various agents at optimal concentrations were normal, ruling out a leukocyte adhesion deficiency syndrome, a Chediak Higashi syndrome, and a chronic granulomatous disease. Nevertheless, the patient's PMNs and monocytes showed defective priming capacity, as measured by H(2)O(2) production after pretreatment with LPS (5 microg/mL for 30 min), TNFalpha (100 units/mL for 30 min), or IL-8 (50 ng/mL for 30 min) in response to bacterial N-formyl peptides (fMLP 10(-6) M for 5 min). In these conditions, H(2)O(2) production of PMNs and monocytes from the patient did not exceed that of the samples treated with fMLP or LPS alone, while the controls strongly produced H(2)O(2). Moreover, monocytes from the patient showed an impaired capacity to kill S. typhimurium in vitro. Such an impairment could be related at least in part to the priming deficiency of phagocyte oxidative burst. This case suggests, for the first time, that in vivo priming processes are critical in host defence against intracellular pathogens.

Adult↗
PubMed1999

Site-specific consultation for a chemical mixture.

The Agency for Toxic Substances and Disease Registry (ATSDR) uses the weight of evidence methodology to evaluate interactions of chemical mixtures. In the process, toxicity, toxicokinetics, and toxicodynamics of chemical components of the mixture are carefully examined. Based on the evaluation, predictions are made that can be used in real-life situations at hazardous waste sites. In this paper, health outcomes were evaluated for a mixture of eight compounds that were found at a specific site. These eight chemicals were identified and possibly associated with human exposure. The health assessors could consider similar thought processes when evaluating chemical mixtures at hazardous waste sites.

Aniline Compounds↗
PubMed1999

Agency for Toxic Substances and Disease Registry's 1997 priority list of hazardous substances. Latent effects--carcinogenesis, neurotoxicology, and developmental deficits in humans and animals.

In support of Superfund re-authorization legislation, the Division of Toxicology of the Agency for Toxic Substances and Disease Registry (ATSDR) prepared a chemical-specific consultation document for Congress that identified those chemicals with carcinogenic, neurological, or developmental adverse effects having a latency period longer than 6 years. The review was limited to the top 50 substances listed on ATSDR's 1997 Priority List of Hazardous Substances (Priority List). Among the top 50 chemicals, a review of the technical literature indicated that 38 (76%) were classified as "reasonably anticipated," "possibly," or "probably" capable of causing cancer in humans, based either on human and animal data. Eight chemicals (16%) had well-established cancer latency periods in humans of 6 years or more following exposure. Three substances (6%)--arsenic, creosote, and benzidine--had data indicating latency periods longer than 6 years. The technical literature review likewise confirmed the potential for neurological and developmental effects with a latency of 6 years. Twenty-seven (54%) of the top 50 substances caused acute and/or chronic neurotoxic effects; a number of these also caused neurological effects that persisted beyond 6 years (or the equivalent in animal studies) such as: behavioral problems, neurological deficiencies, reduced psychomotor development, cognitive deficiencies, and reduced IQ. Twenty-eight substances (56%) caused adverse developmental effects in offspring of exposed individuals or animals including increased fetal and infant mortality, decreased birth weights and litter sizes, and growth delays. Latency periods for related chemicals are expected to be similar due to structural and toxicological similarities.

Animals↗
PubMed1999

ATSDR evaluation of health effects of chemicals. VI. Di(2-ethylhexyl)phthalate. Agency for Toxic Substances and Disease Registry.

Di(2-ethylhexyl)phthalate (also known as DEHP, bis(2-ethylhexyl)phthalate, or BEHP; CAS Registry Number 117-81-7) is a widely-used plasticizer. It is found in numerous plastic articles, such as paints, inks, floor tiles, upholstery, shower curtains, footwear, plastic bags, food-packaging materials, toys, and medical tubing. Not surprisingly, DEHP appears at many waste sites. As part of its mandate, the Agency for Toxic Substances and Disease Registry (ATSDR) prepares toxicological profiles on hazardous chemicals that are of greatest public health concern at Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) National Priority List (NPL) sites. These profiles comprehensively summarize toxicological and environmental information. This article constitutes the release of the bulk of ATSDR's profile for DEHP (ATSDR, 1993) into the mainstream scientific literature. An extensive listing of human and animal health effects, organized by route, duration, and endpoint, is presented. Toxicological information on toxicokinetics, biomarkers, interactions, sensitive subpopulations, reducing toxicity after exposure, and relevance to public health is also included. Environmental information encompasses physical properties, production and use, environmental fate, levels seen in the environment, analytical methods, and a listing of regulations. ATSDR, at the behest of Congress and therefore the citizenry, prepares these profiles to inform the public about site contaminants.

Biomarkers↗
PubMed1999

[Detection of Helicobacter pylori by polymerase reaction in bile samples from gallbladder and bile stones].

Some papers report helicobacter pylori existence in bile from surgical specimens obtained during gallbladder or bile ducts surgery. The aim of this work was search by PCR, H. Pylori presence in bile specimens from patients suffering of gallbladder stones or by bile ducts stones. Bile samples were obtained by gallbladder punction during cholecystectomy in 26 patients, 19 of them with gallbladder stones and 7 also with gallbladder stones and bile duct stones. Age ranged from 22-69 years old, median 49.6 years old. Samples were sent to specialized biomolecular laboratory to perform PCR techniques. Two of 26 patients (7.6%) had positive reaction for the presence of DNA of H. Pylori in bile samples. Our research suggest that DNA of H. Pylori can be founded in bile samples patients with gallbladders and duct stones in Argentina.

Adult↗
PubMed1998

Lack of IL-10 and IL-13 production by human polymorphonuclear neutrophils.

The ability of polymorphonuclear neutrophils (PMN) to produce and release numerous pro-inflammatory cytokines is now established and play an important role in triggering and maintaining the inflammatory response. We studied the autocrine downregulation of this process by investigating the potential production by human PMN of two major anti-inflammatory cytokines, interleukin 10 (IL-10) and IL-13. The authors' PMN purification method, based in part on immunomagnetic depletion, allows the elimination of all cells known to produce those two cytokines. A wide range of activation conditions were tested and kinetic studies were done. IL-10 and IL-13 proteins were not detected in culture supernatants or cell lysates of PMN from 13 healthy volunteers. This was confirmed by the absence of IL-10 and IL-13 mRNA expression, as shown by RT-PCR. Human PMN thus seem unable to produce or release two of the most potent anti-inflammatory cytokines, IL-10 and IL-13. This could partly account for the persistence of local inflammation, where PMN are the main infiltrating cells.

Gene Expression↗
PubMed1998

Expression of TWIK-1, a novel weakly inward rectifying potassium channel in rat kidney.

Several K+ conductances have been identified in the kidney, with specific properties and localization in distinct cell types and membrane domains. On the other hand, several K+ channels have been characterized at the molecular level. By immunolocalization, we show that a new inward rectifying K+ channel, TWIK-1, is specifically expressed in distinct tubular segments and cell types of the rat kidney. In the proximal tubule, TWIK-1 prevails in the initial portions (convoluted part), where it is restricted to the apical (brush-border) membrane. In the collecting duct, immunofluorescence was intracellular or confined to the apical membrane and restricted to intercalated cells, i.e., in cells lacking aquaporin-2, as shown by double immunofluorescence. TWIK was also expressed in medullary and cortical parts of the thick limb of the loop of Henle, identified with an anti-Tamm-Horsfall protein antibody (double immunofluorescence). The intensity of TWIK-1 immunolabeling was unchanged in rats fed a low-Na+ or a low-K+ diet. Because TWIK-1 shares common properties with the low-conductance apical K+ channel of the collecting duct, we propose that it could play a role in K+ secretion, complementary to ROMK, another recently characterized K+ channel located in principal cells of the cortical collecting duct and in the loop of Henle.

Animals↗
PubMed1998

Public health challenges posed by chemical mixtures.

Approximately 40 million people live within a 4-mile radius of waste sites that the Agency for Toxic Substances and Disease Registry (ATSDR) has assessed to date. Human populations living in the vicinity of such sites are often subjected to complex chemical exposures that may contribute to the total body burden of oxogenous chemicals. Apart from the contaminants found at waste sites, exposure may also include environmental, occupational, and personal agents. Concurrent exposure to chemicals such as welding fumes, indoor air pollutants, tobacco smoke, alcohol, and prescription and nonprescription drugs makes the health assessment of exposure to waste site chemicals a more complex task. Voluntary exposures such as these frequently entail exposures to relatively high chemical concentrations and can usually be well defined and quantified. Conversely, involuntary exposures from waste sites may be at low concentrations and hence difficult to characterize and quantify. Of the approximately 1450 waste sites evaluated by the ATSDR, 530 (37%) had either completed or potentially completed exposure pathways. Results of public health assessments conducted at 167 sites during 1993 to 1995 show that about 1.5 million people have been exposed to site-specific contaminants. At 10% or more of the sites that had either completed or potentially completed exposure pathways, 56 substances were identified. Of these, 19 are either known or anticipated human carcinogens, and 9 are associated with reproductive or endocrine-disrupting effects. In this paper we present important concerns regarding hazardous waste sites including the impact on human health, ecology, and quality of life. To address such human-health related issues, the ATSDR has established a mixtures program that consists of three components: trend analysis to identify combinations of chemicals of concern, experimental studies to identify data that would be useful in the development and implementation of predictive decision support methodologies, and development of assessment methodologies and guidance to provide health assessors with the tools to incorporate the evaluation of multiple-chemical exposure into site assessments.

Animals↗
PubMed1998

[Post-treatment assessment of Helicobacter pylori eradication, by polymerase chain reaction in gastric biopsies].

BACKGROUND: The pre-treatment detection of H.p. in the stomach of patients is easily achieved with routine methods. Conversely, with conventional methods, it is difficult to detect the presence of H.p. after treatment. OBJECTIVE: To estimate the actual percentage of successfully treated patients by using a more sensitive and specific technique (PCR) in the same biopsies where standard methods were negative for H.p. MATERIALS AND METHODS: We selected 97 treated patients (31 Gastric Ulcers/66 Duodenal Ulcers, 62 male/35 female, age: 49 +/- 14 years), in whom success of treatment was defined by histological means and CLO Test. In the same gastric biopsies H.p-DNA PCR was performed. Different therapeutic schemes were utilized, but all included Proton Pump Inhibitors + ATB. Eight weeks after the end of the treatment, without medication, the patients were controlled as follows: 5 biopsies per patient, 2 of antrum, 2 of corpus (in different zones) and 1 for CLO Test. H.p. eradication was defined on histological grounds (gastric biopsy histology: 10% formaldehide buffer fixation, paraffin inclusion, Giemsa, HE staining and inmunohistochemistry), CLO Test (Delta West Pty. Ltd. Bentley, Australia) and by the absence of H.p.-DNA by PCR (amplification of a 296 bp of the species-specific antigen of H.p. and visualization of the amplified product in agarose gel with Ethidium Bromide and UV light). RESULTS: [table: see text] CONCLUSIONS: The higher sensitivity of PCR (10(3) fold more than conventional methods) allowed us in this group of patients to detect 13% of false eradication. It would be necessary to follow up this group of patients in order to know whether they develop or not clinical symptoms and/or histological evidence of disease. If such a case PCR could become an important tool for treatment evaluation.

Adult↗