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Biomedical subjects

P E Taylor

Publications and source records attributed to P E Taylor.

At least 19 recordsLinked to original sources
PubMed2004

Birch pollen rupture and the release of aerosols of respirable allergens.

BACKGROUND: Birch pollen allergens have been implicated as asthma triggers; however, pollen grains are too large to reach the lower airways where asthmatic reactions occur. Respirable-sized particles containing birch pollen allergens have been detected in air filters, especially after rainfall but the source of these particles has remained speculative. OBJECTIVE: To determine the processes by which birch pollen allergens become airborne particles of respirable size with the potential to contribute to airways inflammation. METHODS: Branches with attached male catkins were harvested and placed in a controlled emission chamber. Filtered dry air was passed through the chamber until the anthers opened, then they were humidified for 5 h and air-dried again. Flowers were disturbed by wind generated from a small electric fan. Released particles were counted, measured and collected for immuno-labelling and high-resolution microscopy. RESULTS: Birch pollen remains on the dehisced anther and can rupture in high humidity and moisture. Fresh pollen takes as long as 3 h to rupture in water. Drying winds released an aerosol of particles from catkins. These were fragments of pollen cytoplasm that ranged in size from 30 nm to 4 microm and contained Bet v 1 allergens. CONCLUSION: When highly allergenic birch trees are flowering and exposed to moisture followed by drying winds they can produce particulate aerosols containing pollen allergens. These particles are small enough to deposit in the peripheral airways and have the potential to induce an inflammatory response.

Allergens↗
PubMed1999

Immunologic significance of respirable atmospheric starch granules containing major birch allergen Bet v 1.

BACKGROUND: Birch-pollen allergens are an important cause of early spring hay fever and allergic asthma. Recently, we reported a mechanism for the release of respirable allergenic particles from birch pollen containing the major allergen Bet v 1. In this study, we aimed to assess the immunologic significance of the released Bet v 1-containing starch granules in the environment. METHODS: A two-site monoclonal antibody-based assay (ELISA) was employed to quantitate Bet v 1 in high-volume air sampler filter extracts, and immunogold-labelling was used on sections of these extracts to localize Bet v 1. Immunoblot analyses were performed with pooled sera from patients sensitive to birch pollen. RESULTS: Atmospheric starch granules contained Bet v 1, and the concentration increased upon light rainfall. Sera from patients allergic to birch allergens recognized extracts from isolated starch granules. CONCLUSIONS: The clinical implications of these findings are that starch granules released from birch pollen are potentially able to trigger allergic asthmatic reactions to Bet v 1, since the allergen occurs in respirable particles. Thus, clinicians can advise asthma patients to remain indoors on days of light rainfall during the birch-pollen season to avoid high levels of allergen exposure.

Air Pollution↗
PubMed1999

Concentrations of major grass group 5 allergens in pollen grains and atmospheric particles: implications for hay fever and allergic asthma sufferers sensitized to grass pollen allergens.

BACKGROUND: Grass pollen allergens are the most important cause of hay fever and allergic asthma during summer in cool temperate climates. Pollen counts provide a guide to hay fever sufferers. However, grass pollen, because of its size, has a low probability of entering the lower airways to trigger asthma. Yet, grass pollen allergens are known to be associated with atmospheric respirable particles. OBJECTIVE: We aimed (1) to determine the concentration of group 5 major allergens in (a) pollen grains of clinically important grass species and (b) atmospheric particles (respirable and nonrespirable) and (2) to compare the atmospheric allergen load with clinical data to assess different risk factors for asthma and hay fever. METHODS: We have performed a continuous 24 h sampling of atmospheric particles greater and lower than 7.2 microm in diameter during the grass pollen season of 1996 and 1997 (17 October 1996-16 January 1997) by means of a high volume cascade impactor at a height of about 15 m above ground in Melbourne. Using Western analysis, we assessed the reactivity of major timothy grass allergen Phl p 5 specific monoclonal antibody (MoAb) against selected pollen extracts. A MoAb-based ELISA was then employed to quantify Phl p 5 and cross-reactive allergens in pollen extracts and atmospheric particles larger and smaller than 7.2 microm. RESULTS: Phl p 5-specific MoAb detected group 5 allergens in tested grass pollen extracts, indicating that the ELISA employed here determines total group 5 allergen concentrations. On average, 0.05 ng of group 5 allergens were detectable per grass pollen grain. Atmospheric group 5 allergen concentrations in particles > 7.2 microm were significantly correlated with grass pollen counts (rs = 0.842, P < 0. 001). On dry days, 37% of the total group 5 allergen load, whereas upon rainfall, 57% of the total load was detected in respirable particles. After rainfall, the number of starch granule equivalents increased up to 10-fold; starch granule equivalent is defined as a hypothetical potential number of airborne starch granules based on known pollen count data. This indicates that rainfall tended to wash out large particles and contributed to an increase in respirable particles containing group 5 allergens by bursting of pollen grains. Four day running means of group 5 allergens in respirable particles and of asthma attendances (delayed by 2 days) were shown to be significantly correlated (P < 0.001). CONCLUSION: Here we present, for the first time, an estimation of the total group 5 allergen content in respirable and nonrespirable particles in the atmosphere of Melbourne. These results highlight the different environmental risk factors for hay fever and allergic asthma in patients, as on days of rainfall following high grass pollen count, the risk for asthma sufferers is far greater than on days of high pollen count with no associated rainfall. Moreover, rainfall may also contribute to the release of allergens from fungal spores and, along with the release of free allergen molecules from pollen grains, may be able to interact with other particles such as pollutants (i.e. diesel exhaust carbon particles) to trigger allergic asthma.

Air Pollutants↗
PubMed1998

Outcomes among 562 recipients of placental-blood transplants from unrelated donors.

BACKGROUND: A program for banking, characterizing, and distributing placental blood, also called umbilical-cord blood, for transplantation provided grafts for 562 patients between August 24, 1992, and January 30, 1998. We evaluated this experience. METHODS: Placental blood was stored under liquid nitrogen and selected for specific patients on the basis of HLA type and leukocyte content. Patients were prepared for the transplantation of allogeneic hematopoietic cells in the placental blood and received prophylaxis against graft-versus-host disease (GVHD) according to routine procedures at each center. RESULTS: Outcomes at 100 days after transplantation were known for all 562 patients, and outcomes at 1 year for 94 percent of eligible recipients. The cumulative rates of engraftment among the recipients, according to actuarial analysis, were 81 percent by day 42 for neutrophils (median time to engraftment, 28 days) and 85 percent by day 180 for platelets (median, day 90). The speed of myeloid engraftment was associated primarily with the leukocyte content of the graft, whereas transplantation-related events were associated with the patient's underlying disease and age, the number of leukocytes in the graft, the degree of HLA disparity, and the transplantation center. After engraftment, age, HLA disparity, and center were the primary predictors of outcome. Severe acute GVHD (grade III or IV) occurred in 23 percent of patients, and chronic GVHD occurred in 25 percent. The rate of relapse among recipients with leukemia was 9 percent within the first 100 days, 17 percent within 6 months, and 26 percent by 1 year. These rates were associated with the severity of GVHD, type of leukemia, and stage of the disease. CONCLUSIONS: Placental blood is a useful source of allogeneic hematopoietic stem cells for bone marrow reconstitution.

Actuarial Analysis↗
PubMed1998

Genetic control of male fertility in Arabidopsis thaliana: structural analyses of postmeiotic developmental mutants.

Seven new male-sterile mutants (ms7-ms13) of Arabidopsis thaliana (L.) Heynh. (ecotype columbia) are described that show a postmeiotic defect of microspore development. In ms9 mutants, microspores recently released from the tetrad appear irregular in shape and are often without exines. The earliest evidence of abnormality in ms12 mutants is degeneration of microspores that lack normal exine sculpturing, suggesting that the MS12 product is important in the formation of pollen exine. Teratomes (abnormally enlarged microsporocytes) are also occasionally present and each has a poorly developed exine. In ms7 mutant plants, the tapetal cytoplasm disintegrates at the late vacuolate microspore stage, apparently causing the degeneration of microspores and pollen grains. With ms8 mutants, the exine of the microspores appears similar to that of the wild type. However, intine development appears impaired and pollen grains rupture prior to maturity. In ms11 mutants, the first detectable abnormality appears at the mid to late vacuolate stage. The absence of fluorescence in the microspores and tapetal cells after staining with 4',6-diamidino-2-phenylindole (DAPI) and the occasional presence of teratomes indicate degradation of DNA. Viable pollen from ms10 mutant plants is dehisced from anthers but appears to have surface abnormalities affecting interaction with the stigma. Pollen only germinates in high-humidity conditions or during in-vitro germination experiments. Mutant plants also have bright-green stems, suggesting that ms10 belongs to the eceriferum (cer) class of mutants. However, ms10 and cer6 are non-allelic. The ms13 mutant has a similar phenotype to ms10, suggesting is also an eceriferum mutation. Each of these seven mutants had a greater number of flowers than congenic male-fertile plants. The non-allelic nature of these mutants and their different developmental end-points indicate that seven different genes important for the later stages of pollen development have been identified.

Arabidopsis↗
PubMed1997

Willingness to participate in HIV-1 vaccine efficacy trials and the effect of media events among gay and bisexual men in New York City: Project ACHIEVE.

Efficacy trials of candidate HIV-1 vaccines require study populations at high risk of infection who adhere to study protocols and who are willing to participate. Data from HIV-1 antibody-negative men (n = 698) enrolled in Project ACHIEVE in New York City were analyzed to assess willingness to participate in efficacy trials, factors influencing willingness, and the effect on willingness of the June 1994 media events about the decision not to proceed with phase III trials and about breakthrough infections during phase I and II vaccine trials. Sixty-eight percent indicated they would definitely or probably be willing to participate. Men enrolled during the time of media events were significantly less willing compared with men enrolled during other periods. These men were also more likely to mention safety of the vaccine, fear or mistrust of research or government, and social risks as important factors in their decision compared with men enrolled during other periods. The most frequently cited motivator for participation was altruism (57%); the most frequently cited barriers were vaccine safety (36%) and vaccine-induced seropositivity (19%). A substantial proportion of this cohort was willing to participate in future vaccine efficacy trials. However, because willingness may be affected by issues of vaccine safety, vaccine-induced seropositivity, and media coverage of these issues, significant efforts are needed for participant and community education, and specific concerns must be addressed in the design and implementation of trials.

Adult↗
PubMed1997

Concentrations of the major birch tree allergen Bet v 1 in pollen and respirable fine particles in the atmosphere.

BACKGROUND: Birch tree pollen allergens are an important cause of early spring hay fever and allergic asthma. Pollen counts provide a guide for individuals with birch pollen allergy. However, birch pollen, because of its size, has a low probability of entering the lower airways to trigger asthma. Yet birch pollen allergens are known to be associated with respirable particles present in the atmosphere. OBJECTIVE: We sought to determine the concentration of major allergen Bet v 1 in birch pollen and respirable particles in the atmosphere during the birch pollen season. METHODS: We used a two-site monoclonal antibody-based assay (ELISA) to quantitate Bet v 1 in pollen extracts and high-volume air sampler filters collecting particles larger and smaller than 7.2 microm. RESULTS: Bet v 1 (0.006 ng) is detectable per birch pollen grain, of which 0.004 ng is present in aqueous extracts (13.9% of soluble proteins). Atmospheric Bet v 1 concentrations are correlated with birch pollen counts. Heavy rainfall tended to wash out pollen and particles, indicated by a mean daily Bet v 1 concentration of 0.12 ng/m3 (20 pollen equivalents), but light rainfall produced a dramatic increase in allergen-loaded respirable particles with Bet v 1 concentrations of 1.2 ng/m3 (200 pollen equivalents). CONCLUSION: These results highlight the different environmental risk factors for hay fever and allergic asthma in patients sensitized to Bet v 1. Light rainfall causes an increase in respirable particles; hence, this is an important risk factor for asthma.

Air Pollution↗
PubMed1996

Increased incidence of cancer among homosexual men, New York City and San Francisco, 1978-1990.

Several studies have shown that human immunodeficiency virus type 1 (HIV-1) is associated with an increase in the incidence of Kaposi's sarcoma and non-Hodgkin's lymphoma among homosexual men. The role of HIV-1 in increasing the incidence of other malignancies is more controversial. The incidence of non-Kaposi's sarcoma cancer was examined from 1978 to 1990 among 15,565 homosexual men who participated in studies of hepatitis B virus infection in the late 1970s in New York City, New York, and San Francisco, California. The standardized incidence ratio (SIR) for all cancers was 1.6 (95% confidence interval (CI) 1.4-1.8). Excesses were observed for non-Hodgkin's lymphoma (SIR = 12.7; 95% CI 11.0-14.6). Hodgkin's disease (SIR = 2.5; 95% CI 1.5-3.9), and anal cancer (SIR = 24.2 95% CI 13.5-39.9). As seen with non-Hodgkin's lymphoma, a cancer known to be associated with HIV-1. Hodgkin's disease incidence was significantly higher in more recent years compared with earlier years. No cases of Hodgkin's disease were found among HIV-1 antibody-negative men, and Hodgkin's disease was diagnosed near the time of initial acquired immunodeficiency syndrome diagnoses. Anal cancer incidence did not correlate with HIV-1 antibody status and did not tend to occur near the time of AIDS diagnoses. This study confirms the association of non-Hodgkin's lymphoma with HIV-1 infect on and suggests an association between Hodgkin's disease and HIV-1 infection. An excess in anal cancer was observed but did not appear to be associated with HIV-1 infection.

Acquired Immunodeficiency Syndrome↗
PubMed1996

The feasibility of HIV-1 vaccine efficacy trials among gay/bisexual men in New York City: Project ACHIEVE. AIDS Community Health Initiative Enroute to the Vaccine EFfort.

OBJECTIVE: Candidate populations for HIV-1 vaccine efficacy trials need to be at high risk of infection, adhere to study protocols and be willing to participate. The goal of Project ACHIEVE is to collect baseline data needed in order to prepare for vaccine efficacy trials among gay/bisexual men in New York City. DESIGN AND METHODS: HIV-1 antibody-negative men were recruited into a cohort study with follow-up visits every 3 months (n = 622). Frequency of high-risk behaviors and incidence of HIV-1 seroconversion were measured. RESULTS: Of 544 men reporting having had at least one partner in the previous 3 months who was HIV-1 antibody-positive or of unknown status at baseline, 49% reported receptive anal sex encounters. Thirty-two per cent of these men reported the highest risk behavior, unprotected receptive anal sex. The follow-up rate at 12 months was 81%. The incidence rate of infection was 2.9 per 100 person-years (95% confidence interval: 1.7, 4.9). During follow-up, declines were observed in the proportion of men with an HIV-1 antibody-positive partner and the proportion reporting unprotected receptive or insertive anal sex. HIV-1 infection rates declined from 4.3 per 100 person-years in the first 6 months to 1.6 per 100 person-years by the 12-month visit. CONCLUSIONS: Gay/bisexual men in New York City are still placing themselves at risk of HIV-1 infection and may be a suitable population for future vaccine trials. Continued follow-up is needed to further define the incidence over time, especially for the period after the initial 3 to 6 months when vaccines are most likely to be effective. Immediate prevention efforts need to target this population more effectively.

AIDS Vaccines↗
PubMed1996

Stability in controlling viral replication identifies long-term nonprogressors as a distinct subgroup among human immunodeficiency virus type 1-infected persons.

Long-term nonprogressors (LTNPs) of human immunodeficiency virus type 1 (HIV-1) infection are characterized by low levels of HIV-1 replication and viral load. However, it has not been established whether they differ in this regard from progressors from the very early stage of infection. By studying peripheral blood mononuclear cell (PBMC) specimens from a longitudinally monitored cohort of HIV-1-infected men, we found that HIV-1 proviral copy numbers and HIV-1 mRNA expression levels as low or lower than those seen in seven carefully selected LTNPs were commonly observed in specimens collected soon after seroconversion from 28 subjects who became infected while under observation. However, only the LTNPs were able to stably maintain such an efficient viral control over time. Because of the instability of the early control of HIV-1 replication, the predictive value of HIV-1 mRNA expression in PBMCs at postseroconversion was found to be limited but significantly increased during the first year of infection. Besides their diagnostic implications, these data support the idea that LTNPs may be a pathophysiologically distinct subgroup among persons infected with HIV-1.

Cohort Studies↗
PubMed1995

HIV-1 messenger RNA in peripheral blood mononuclear cells as an early marker of risk for progression to AIDS.

OBJECTIVE: To establish human immunodeficiency virus type 1 (HIV-1) messenger RNA (mRNA) expression in peripheral blood mononuclear cells as a marker of risk for progression to the acquired immunodeficiency syndrome (AIDS) in a large cohort of HIV-infected persons followed for a prolonged period. DESIGN: Retrospective testing of cryopreserved, coded specimens. SETTING: Research laboratories at the New York Blood Center and the Rockefeller University. PATIENTS: 150 homosexual men infected with HIV-1 who did not have an AIDS diagnosis at the time of testing. MEASUREMENTS: Multiply spliced and unspliced HIV-1 mRNAs in total peripheral blood mononuclear cell RNA were quantitated using reverse transcriptase-initiated polymerase chain reaction (PCR) and compared with other laboratory data and clinical outcome during the subsequent 8 years. RESULTS: Although HIV-1 mRNA expression generally correlated with immunologic status, it was associated with future disease progression independently of CD4+ cell counts or their rate of decrease at the time of sampling. The association of HIV-1 mRNA with disease progression in persons with CD4+ cell counts higher than the median (> 624 cells/mm3) was particularly noteworthy; further variation in the CD4+ cell counts within this group was not prognostically significant. CONCLUSIONS: The expression of HIV-1 mRNA in peripheral blood mononuclear cells is a strong independent marker for future HIV disease progression, even in persons with normal T-cell subsets.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Processing and cryopreservation of placental/umbilical cord blood for unrelated bone marrow reconstitution.

Clinical evidence of hematopoietic restoration with placental/umbilical cord blood (PCB) grafts indicates that PCB can be a useful source of hematopoietic stem cells for routine bone marrow reconstitution. In the unrelated setting, human leukocyte antigen (HLA)-matched donors must be obtained for candidate patients and, hence, large panels of frozen HLA-typed PCB units must be established. The large volume of unprocessed units, consisting mostly of red blood cells, plasma, and cryopreservation medium, poses a serious difficulty in this effort because storage space in liquid nitrogen is limited and costly. We report here that almost all the hematopoietic colony-forming cells present in PCB units can be recovered in a uniform volume of 20 ml by using rouleaux formation induced by hydroxyethyl starch and centrifugation to reduce the bulk of erythrocytes and plasma and, thus, concentrate leukocytes. This method multiples the number of units that can be stored in the same freezer space as much as 10-fold depending on the format of the storage system. We have also investigated the proportion of functional stem/progenitor cells initially present that are actually available to the recipient when thawed cryopreserved PCB units are infused. Progenitor cell viability is measurably decreased when thawed cells, still suspended in hypertonic cryopreservative solutions, are rapidly mixed with large volumes of isotonic solutions or plasma. The osmotic damage inflicted by the severe solute concentration gradient, however, can be averted by a simple 2-fold dilution after thawing, providing almost total recovery of viable hematopoietic progenitor cells.

Blood Cell Count↗
PubMed1995

Bcp1, a gene required for male fertility in Arabidopsis.

Male fertility in flowering plants is dependent on production of viable pollen grains within the anther. Genes expressed exclusively in the anther are likely to include those that control male fertility. On the basis of their tissue specificity, such genes have been isolated, yet in none of them has this function been demonstrated. Here we report that one such gene, Bcp1, is active in both diploid tapetum and haploid microspores and is required for pollen fertility. Perturbation of this gene in either tapetum or microspores prevents production of fertile pollen in transgenic Arabidopsis plants. When tapetum expression of this gene is perturbed, mature anthers contain dead shriveled pollen. On the other hand, when microspore expression is perturbed, anthers show 1:1 segregation of viable/aborted pollen. These findings identify a class of sporophytic/gametophytic genes controlling male fertility and, hence, reproduction in flowering plants.

Amino Acid Sequence↗
PubMed1994

Localization of the two major allergens in rye-grass pollen using specific monoclonal antibodies and quantitative analysis of immunogold labelling.

The intracellular localization of the two major allergens, Lol p I and Lol p IX, in rye-grass anthers was examined using monoclonal antibodies FMCA1 (specific for Lol p I) and FMCA7 (specific for Lol p IX) with immunocytochemical techniques and quantitative analysis. A newly developed anhydrous fixation technique in a mixture of glutaraldehyde, paraformaldehyde and 2,2-dimethoxypropane followed by embedding in LR Gold resin resulted in both improved infiltration of pollen grains compared with existing techniques and the localization of these water-soluble antigens in their original sites compared with diffusion artefacts following aqueous methods. After anhydrous fixation, Lol p I was predominantly located in the electron-opaque regions of the cytosol of the vegetative cell of the tricellular pollen grains (24 counts microns-2), whereas Lol p IX was detected mainly within starch granules (16 counts microns-2). For both Lol p I and Lol p IX, similar labelling was detected in the cells of the endothecium and middle layer (18 counts microns-2), but none was found in the tapetal cells or orbicules.

Allergens↗