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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Epidemiology of human immunodeficiency virus type 1 infection among homosexual men participating in hepatitis B vaccine trials in Amsterdam, New York City, and San Francisco, 1978-1990

Homosexual/bisexual men from Amsterdam, The Netherlands, New York, New York, and San Francisco, California, were entered into trials of the efficacy of hepatitis B vaccine shortly before the acquired immunodeficiency syndrome (AIDS) epidemic was recognized (1978-1980). The authors analyzed data, including serial blood samples tested for antibody to human immunodeficiency virus type 1 (HIV-1) as well as demographic and behavioral information, to characterize the spread of HIV-1 infection within the cohorts. By the end of 1982, the cumulative incidence of HIV-1 infection within the cohorts. By the end of 1982, the cumulative incidence of HIV-1 infection was 7.5% in Amsterdam, 26.8% in New York City, and 42.6% in San Francisco. Covariate analysis showed that differences in sexual activity (number of male sexual partners) and correlates of sexual activity (age and hepatitis B incidence) accounted for the differences in incidence of HIV-1 infection between the New York City and San Francisco cohorts. These covariates did not explain the lower incidence in the Amsterdam cohort. In conclusion, significant differences were found in the spread of HIV-1 in cohorts of homosexual men in Amsterdam, New York City, and San Francisco. These dissimilarities were probably due to a combination of differences in sexual activity at the time the epidemic began and a later introduction of HIV-1 in Amsterdam.

Effect of sensory denervation on the response of rat molar pulp to exposure injury

Sensory nerve fibers that contain calcitonin gene-related peptide (CGRP) have been shown previously to sprout into inflamed tissue surrounding sites of pulpal injury. The sprouting fibers contain increased CGRP immunoreactivity (IR), and neuropeptide levels increase in the surrounding pulp. We compared denervated and innervated first mandibular molars of rats to determine whether the absence of sensory nerve fibers affected tissue survival and healing after pulp exposure. Significant differences were seen between innervated and denervated teeth six days after occlusal exposure, with more extensive necrosis in the denervated teeth, and less survival of vascular pulp. When exposures were on the side of the crown, there was no significant difference between the innervated and denervated teeth. Both the innervated and denervated teeth had begun to make reparative dentin and osteodentin by six days after tooth injury. This study shows that teeth with sensory denervation had an accelerated loss of pulp tissue following occlusal exposure compared with innervated teeth with similar injury.

Mortality trends in a cohort of homosexual men in New York City, 1978-1988

Trends in mortality related to infection by human immunodeficiency virus type 1 (HIV-1) and to other causes were examined from 1978 to 1988 in a cohort of 8,906 homosexual men who participated in studies of hepatitis B virus infection in the late 1970s in New York City. HIV-related mortality rates increased from 1 per 10,000 person-years in 1980 to 181 per 10,000 person-years in 1986, followed by a plateau from 1986 to 1988. The standardized mortality ratio among white men in the cohort was 3.7 (95% confidence interval (Cl) 3.4-3.9) as compared with white men from across the United States. Higher HIV-related mortality rates were associated with a higher number of sexual partners, a history of gonorrhea and/or syphilis, and serologic markers of infection with hepatitis B virus. After adjustment for demographics and sexual behaviors, the relative risk of mortality for Hispanic men as compared with white men was 1.5 (95% Cl 1.1-1.9). This study illustrates the large excess in mortality among homosexual men over the last decade, with the excess accounted for by deaths from HIV-related diseases. The recent plateau in mortality may be due to the effect of new treatments and/or the decline in new HIV-1 infections among homosexual men. The excess in HIV-related mortality among Hispanic homosexual men was not explained by differences in demographics and factors associated with the sexual transmission of HIV-1.

Prospects for control of hepatitis B virus infection: implications of childhood vaccination and long-term protection

Hepatitis B vaccine has been recommended for high-risk individuals in the United States for more than a decade. This targeted strategy, however, has failed to control hepatitis B virus (HBV) infection. Universal immunization is being considered as an alternative approach, in particular the inclusion of hepatitis B vaccine with routine childhood vaccinations. Data presented herein demonstrate a high degree of efficacy for hepatitis vaccine with hepatitis B immune globulin in preventing perinatal HBV infection in newborns. Immune response to vaccine was dependent in part on the dose administered, with some enhancement of response if the infant was older at the time of initial injection or if the booster dose was given later. Long-term follow-up showed persistence of vaccine-induced antibody for 5 to 10 years in 90% of immunized infants and adults. Only 3% to 5% of these high-risk individuals had serologic evidence of an HBV infection. None of the infections had been symptomatic and none resulted in a chronic HBV carrier state. Thus, immune responses and efficacy of hepatitis B vaccine in infants were excellent, and immunity and protection against clinically significant HBV infection persisted for at least 5 to 10 years, features essential to success of a program of universal childhood immunization against HBV.

Effect of duration of hepatitis B virus infection on the association between human immunodeficiency virus type-1 and hepatitis B viral replication

This study examined the effect of duration of hepatitis B virus infection on the association between human immunodeficiency virus type-1 infection and hepatitis B viral replication. Twenty-five chronic HBsAg carriers were studied. Presence of hepatitis B virus DNA and expression of HBeAg were more frequent among 20 chronic HBsAg carriers positive for human immunodeficiency virus type-1 antibody compared with five chronic HBsAg carriers negative for human immunodeficiency virus type-1 antibody, but the associations were not statistically significant. Hepatitis B virus DNA and HBeAg were inversely related to duration of hepatitis B virus infection (p less than 0.001). Stratifying for duration of hepatitis B virus infection, the presence of viral replication was similar among patients negative and positive for antibody to human immunodeficiency virus type-1. Hepatitis B virus DNA levels did not increase with the decline of cellular immunity over time. In conclusion, hepatitis B virus replication among chronic carriers may be a function of duration of hepatitis B virus infection rather than of an effect of human immunodeficiency virus type-1.

The interrelationship between the accumulation of lipids, protein and the level of acyl carrier protein during the development of Brassica napus L. pollen

Lipid accumulation during pollen and tapetal development was studied using cryostat sections of unfixed anthers from Brassica napus (rapeseed). Diamidino-2-henylindole (DAPI), a DNA fluorochrome, was used to stain the pollen nuclei in order to identify ten stages of pollen development in Brassica. Storage lipids (i.e. triacylglycerides) were stained using the fluorochrome Nile red. Pollen coat lipids are formed in tapetal plastids between the mid-vacuolate and early maturation pollen stages. The pollen coat components, including lipids and a proportion of the proteins, are derived from the remnants of the tapetum, after its rupture, during the second pollen mitosis. Quantitative microfluorometric analyses demonstrated four phases of lipid body accumulation or depletion in the developing pollen cytoplasm. The majority of storage lipids found in the cytoplasm of the mature pollen grain accumulated during the late vacuolate and early maturation stages when the pollen is bicellular. The level of acyl carrier protein, a protein integrally involved in lipid synthesis, was also found to be maximal in the developing pollen during the bicellular pollen stages of development. This coincided with the most active period of lipid accumulation. These data could indicate that the lipids of the pollen are synthesized in situ, by metabolic processes regulated by expression of genes in the haploid genome.

Occupational risk for hepatitis C virus infection among New York City dentists

Health-care workers have an occupational risk of infection with hepatitis C virus (HCV). However, neither the magnitude of this risk nor the practices associated with it have been defined. Since dentists have numerous patients and are exposed to blood, they are likely to have the maximum risk. Therefore, we have assessed occupational risk for HCV infection among dentists in the New York City area. Individuals who admitted present or previous intravenous drug use or (men) who were homosexual or bisexual were excluded. Demographic, occupational, and behavioural data were recorded, and sera were tested for antibodies to HCV (anti-HCV). Anti-HCV was found in 8 (1.75%) of 456 dentists compared with 1 (0.14%) of 723 controls (odds ratio [OR] 12.9, 95% confidence interval [CI] 1.7 to 573). Anti-HCV was found in 4 (9.3%) of 43 oral surgeons compared with 4 (0.97%) of 413 other dentists (OR 10.5, 95% CI 1.9 to 58). Seropositive dentists claimed to have treated more intravenous drug users in the week (p = 0.04) or month (p = 0.03) before the study than did seronegative dentists. Our findings show that dentists are at increased risk for hepatitis C infection. All health-care workers should regard patients as potentially infected with a communicable bloodborne agent.

Hepatitis C virus infection in post-transfusion hepatitis. An analysis with first- and second-generation assays

BACKGROUND

The causes of post-transfusion non-A, non-B hepatitis are still not fully defined, nor is it clear how accurate the tests are that are used to screen blood donors for hepatitis C virus (HCV) and to diagnose post-transfusion hepatitis caused by infected blood.

METHODS

We used two first-generation enzyme-linked immunoassays (EIAs) and one second-generation immunoassay to test for anti-HCV antibodies in serum samples collected between 1976 and 1979 in the Transfusion-Transmitted Viruses Study (from 1247 patients who underwent transfusion and 1235 matched control subjects who did not receive transfusions). We tested serum collected before and after infection from the patients in whom non-A, non-B hepatitis developed, serum from their blood donors, and serum from 41 of the control subjects who had hepatitis unrelated to transfusion.

RESULTS

Of the 115 patients in whom post-transfusion non-A, non-B hepatitis developed, the initial serum samples of 111 were anti-HCV-negative; after hepatitis developed in these 111 patients, the first-generation EIAs detected anti-HCV in 51 (46 percent), and the second-generation assay detected anti-HCV in an additional 16 (14 percent), for a total of 60 percent. Of 40 controls, 37 were anti-HCV-negative initially, and none seroconverted after hepatitis developed. If the 3 percent rate of non-A, non-B, non-C hepatitis among the controls (37 of 1235) was applied to the 1247 transfusion recipients, only 74 of the 111 cases of hepatitis were attributable to the transfusion. Thus, 91 percent (67 of 74) of the cases of post-transfusion hepatitis were caused by HCV. Of the 99 donors, 60 were HCV-positive (9 on second-generation tests only) and 39 were not.

CONCLUSIONS

Nearly all cases of non-A, non-B post-transfusion hepatitis are caused by HCV. Screening with a second-generation assay improves the rate of detection of HCV infection in patients with post-transfusion hepatitis and in blood donors. The use of this test showed a 3.6 percent risk of non-A, non-B, non-C hepatitis, which was not significantly different from the rate in the controls (3.0 percent).

Screening of selected male blood donors for p24 antigen of human immunodeficiency virus type 1. The Transfusion Safety Study Group

BACKGROUND

The p24 antigen of human immunodeficiency virus type 1 (HIV-1) is sometimes detected before antibody (anti-HIV-1) is detectable in the serum of recently infected persons. This has led to the consideration of p24-antigen testing for routine screening of blood donors.

METHODS

To estimate how many HIV-infected seronegative donors would be identified if p24-antigen screening was introduced, we tested selected donations from a repository of 200,000 serum samples from voluntary donors that was established in late 1984 and early 1985. The 8597 serum samples selected for p24-antigen screening were chosen because their donors had demographic characteristics known to be associated with a high prevalence of seropositivity.

RESULTS

The prevalence of anti-HIV-1 antibodies in the 1984-1985 serum samples selected for p24-antigen screening was 1.54 percent--more than 100 times the 0.012 percent prevalence in present-day donations in the United States. The antigen was detected in 15 of 132 serum samples (11.4 percent) from donors who had already been confirmed as seropositive. No instance of confirmed positivity for p24 antigen was found among the 8465 seronegative serum samples.

CONCLUSIONS

These data indicate that the yield of screening for p24 antigen in volunteer donors to identify HIV-1 carriers would be negligible. We therefore recommend against routine screening with currently available p24-antigen assays.

Human T-cell lymphotropic virus in volunteer blood donors

Serum samples collected in 1985 and 1986 from 18,257 donors to the Greater New York Blood Program were screened by enzyme-linked immunoassay for antibody to human T-cell lymphotropic virus (anti-HTLV). Fifteen samples (0.08%) were confirmed positive: 7 by radioimmunoprecipitation assay (RIPA) alone, 6 by Western blot alone, and 2 by combined results from both tests. One donor, whose original test result was uninterpretable because multiple nonspecific bands were present on RIPA, clearly tested positive on subsequent specimens. Follow-up testing of individuals with this type of result may be needed to resolve their HTLV status. Anti-HTLV prevalence increased with age and was significantly more common in black or Hispanic donors and in those born in the Caribbean than in other donors. All anti-HTLV-positive donors were negative for antibody to HIV-1, and only one donor (7% of those positive) would have been excluded by any of the routine donor screening tests used at that time.

Cellular localization of water soluble, allergenic proteins in rye-grass (Lolium perenne) pollen using monoclonal and specific IgE antibodies with immunogold probes

A postembedding method has been developed for localizing water soluble allergens in rye-grass pollen. This uses dry fixation in glutaraldehyde vapour, followed by 2,2-dimethoxypropane, prior to a 100% ethanol series leading into embedment in LR Gold. This has allowed the attachment of specific monoclonal antibodies to the allergen, which are themselves probed with specific immunogold labels to the antibodies. Wall and cytoplasmic sites have been identified, representing an improvement of fixation and localization of allergens over previous studies employing polyclonal, broad spectrum antibodies. Rye-grass allergens are labelled in mature pollen grains in the exine (tectum, nexine and central chamber), and in the electron opaque areas of the cytoplasm, especially mitochondria. The allergens are absent from the intine, polysaccharide (P) particles, amyloplasts, Golgi bodies and endoplasmic reticulum. IgE antibodies derived from humans allergic to rye-grass pollen, bind to similar sites in the cytoplasm but only to the outer surface of the pollen grain wall. This method now provides a valuable tool for further developmental studies on the pollen grains, in order to establish the site/s of synthesis of the allergens.

Effects of injury and inflammation on pulpal and periapical nerves

Several studies dealing with the reactions of dental nerve fibers to injury and inflammation are reviewed in this article. The subgroup of dental nerve fibers that contains calcitonin gene-related peptide (CGRP) was examined by immunocytochemistry at various times (1 to 35 days) after one of three degrees of injury: (a) Mild: Four days after making shallow cavities into cervical dentin of first molars of anesthetized adult rats, we found that CGRP fibers had sprouted into the subjacent odontoblast layer and dentin, and then returned to normal by 3 wk. (b) Intermediate: If the cervical cavities were acid etched, we found damage to the odontoblast layer, microabscess formation, and sprouting of CGRP fibers near the abscess, with subsequent formation of reparative dentin and healing. (c) Severe: If the pulp was exposed, a variety of reactions could occur, the most prevalent of which was a severe necrosis leading to development of periapical lesions. Analysis of the progressive stages of pulpal abscess and necrosis showed sprouting CGRP nerve fibers (a) at the retreating interface between abscess and vital pulp; (b) in periapical areas during onset of lesions; and (c) around chronic abscesses in granulomatous periodontal tissues. These studies are discussed in relation to various dental clinical problems such as hypersensitive teeth, episodic toothache, early onset of periapical lesions, dental anesthesia, and possible roles for sensory fibers and neuropeptides in tissue defense and healing.

Epidemiology of hepatitis C virus. A preliminary study in volunteer blood donors

In a survey carried out from 1985 through 1986, volunteer blood donors to The Greater New York Blood Program were tested for two surrogate markers for non-A, non-B hepatitis--elevation of alanine aminotransferase level and presence of antibody to hepatitis B core antigen. Stored serum samples from selected donors were also recently tested for antibody to hepatitis C virus (anti-HCV). Anti-HCV was detected in 0.9% to 1.4% of donors and was higher in black and Hispanic donors than in white donors. Anti-HCV prevalence increased with increasing age through the fourth decade of life, but decreased thereafter, possibly reflecting the disappearance of detectable antibody with time. Anti-HCV correlated with both alanine aminotransferase level and the presence or absence of antibody to hepatitis B core antigen. These associations suggest that donor screening for elevation of alanine aminotransferase level and presence of antibody to hepatitis B core antigen was, as expected, at least partially effective in preventing transfusion-associated non-A, non-B hepatitis. The detection of anti-HCV in donors who have neither an elevation of alanine aminotransferase level nor presence of antibody to hepatitis B core antigen suggests that donor screening for anti-HCV will further reduce the risk of transfusion-associated hepatitis.

An immunocytochemical study of the morphological reaction of nerves containing calcitonin gene-related peptide to microabscess formation and healing in rat molars

Pulpal inflammation was induced by cutting a class V cavity to within 0.1-0.3 mm of the pulp on the mesial aspect of maxillary and mandibular first molars at the cervical line. The exposed dentine was briefly acid-etched and left open to the mouth until the animals were killed. Histological examination of teeth 4 days after injury showed microabscesses, blood vessel dilation and increased numbers of terminal nerve sprouts around the lesion and in radicular pulp and dentine. Specimens at 7, 11, 21 and 35 days after injury showed progressive healing of the lesions with the formation of reparative dentine and a coincident return to a normal patterns of innervation in the remaining pulp. Thus pulpal nerves are not static structures, but rather are capable of rapid change in response to inflammation. The morphological association of CGRP-immunoreactive nerve fibres with the edges of the healing lesions and with zones of reparative dentine suggests a role for these fibres and for the neuropeptide CGRP in the healing response of pulpal tissue.

Epidemiologic background of blood donors with antibody to human T-cell lymphotropic virus. Transfusion Safety Study Group

We interviewed 51 blood donors in four major US metropolitan areas subsequently found to have had antibodies to human T-cell lymphotropic virus (anti-HTLV) in late 1984-early 1985. Sixteen donors (31%) reported that they or a sexual contact had a history of blood transfusion. Twelve donors (24%) reported that they or a sexual contact used intravenous drugs. Ten donors (20%) were blacks born in the southeastern US. Four of the male donors (15%) reported homosexual contact. The most common characteristic was an association with Japan or the Caribbean basin (61%). These results show a broader variation of epidemiologic backgrounds than anticipated.

Sprouting of CGRP nerve fibers in response to dentin injury in rat molars

Light and electron microscopic immunocytochemistry showed extensive increases in the number of calcitonin gene-related peptide immunoreactive (CGRP-IR) nerve fibers subjacent to injured root dentin of rat molars. Sprouting was greatest at 4 days and returned to normal 10-21 days post injury. Non-CGRP-IR fibers were also increased at 4 days. The results suggest that rapid reversible sprouting of sensory nerve fibers may be an integral part of tissue reactions to injury.

Yeast-recombinant hepatitis B vaccine. Efficacy with hepatitis B immune globulin in prevention of perinatal hepatitis B virus transmission

A yeast-recombinant hepatitis B vaccine was licensed recently by the Food and Drug Administration and is now available. To assess the efficacy of the yeast-recombinant vaccine, we administered the vaccine in combination with hepatitis B immune globulin to high-risk newborns. If infants whose mothers were positive for both hepatitis B surface antigen and the e antigen receive no immunoprophylaxis, 70% to 90% become infected with the virus, and almost all become chronic carriers. Among infants in this study who received hepatitis B immune globulin at birth and three 5-micrograms doses of yeast-recombinant hepatitis B vaccine, only 4.8% became chronic carriers, a better than 90% level of protection and a rate that is comparable with that seen with immune globulin and plasma-derived hepatitis B vaccine. These data suggest that, in this high-risk setting, the yeast-recombinant vaccine is as effective as the plasma-derived vaccine in preventing hepatitis B virus infection and the chronic carrier state.

Human T-cell lymphotropic virus type III infection in a cohort of homosexual men in New York City

Using blood samples collected since 1978, we investigated the epidemiology of human T-cell lymphotropic virus type III (HTLV-III), the etiologic agent of the acquired immunodeficiency syndrome, in a group of 378 homosexually active men who have resided in New York City since the acquired immunodeficiency syndrome epidemic began. The anti-HTLV-III prevalence was 6.6% in sera from 1978 or 1979, and the subsequent annual incidence of seroconversion among susceptible men ranged between 5.5% and 10.6%. The highest incidences were in recent years, even though these men reported a decrease in their sexual activity during this time. These data demonstrate the continuing risk of HTLV-III infections in the homosexual population studied and emphasize the need for more effective prevention of transmission. The year during which antibody was first present was the only factor identified that was associated with altered cell-mediated immunity in antibody-positive men. Men who became antibody positive in 1981 or earlier currently had significantly lower OKT4/OKT8 ratios than did those who seroconverted more recently. Further follow-up will be necessary to establish the reasons for this association.

Perinatal hepatitis B virus transmission in the United States. Prevention by passive-active immunization

Among infants born to women in whom sera are positive for both the hepatitis B surface antigen and the e antigen, 85% to 90% are infected with hepatitis B virus and become chronic hepatitis B surface antigen carriers. In a study to assess the effectiveness of passive-active prophylaxis (hepatitis B immune globulin and hepatitis B vaccine) of such infants, we screened 18,842 pregnant Asian-American women: 8.7% were positive for hepatitis B surface antigen and 3.0% were also positive for hepatitis B e antigen. Thus far, 113 infants have received hepatitis B immune globulin (0.5 mL at birth) and hepatitis B vaccine (three 20-micrograms doses beginning at birth or at 1 month) and have been followed up for nine to 18 months. Among these infants, 16 have become chronic carriers, an incidence of only 14.2%. All of the uninfected infants have retained high levels of antibody to surface antigen, suggesting that they have had an active immune response to the vaccine and should have long-term protection against hepatitis B virus.

Hepatitis B vaccine in patients receiving hemodialysis. Immunogenicity and efficacy

We evaluated the immunogenicity and efficacy of hepatitis B vaccine (Heptavax-B) in a randomized, double-blind, placebo-controlled trial involving 1311 patients receiving hemodialysis in the United States. After three doses of vaccine (40 micrograms each) had been administered, 63 per cent of the patients were antibody-positive. After correction for possible passive transfer of antibodies by blood transfusion, only 50 per cent of vaccine recipients were considered vaccine responders. The incidence of hepatitis B viral infection during the 25 months of the trial was much lower than had been anticipated and was virtually the same in the vaccine and placebo recipients (6.4 and 5.4 per cent, respectively). Four cases of hepatitis B occurred in patients who had an apparent antibody response to the vaccine, but in each case either antibody had reached low or undetectable levels before hepatitis B surface antigen was detected or the patient had been receiving immunosuppressive therapy. This study did not demonstrate the efficacy of the vaccine in a population of patients receiving dialysis in whom both the rate of antibody response to hepatitis B vaccine and the viral attack rate were low. Other measures to control transmission of hepatitis B virus in dialysis units, including surveillance for hepatitis B surface antigen and isolation of patients who are positive for the antigen, must be continued.

Hepatitis B vaccine in medical staff of hemodialysis units: efficacy and subtype cross-protection

We evaluated the efficacy of hepatitis B vaccine (Heptavax-B) containing only the ad subtype in a randomized, placebo-controlled, double-blind trial among 865 staff members of 43 hemodialysis units in the United States. Surface antibody developed in 92.6 per cent of the subjects after two doses of vaccine and in 96 per cent after the six-month booster. The incidence of infections with hepatitis B virus (with or without hepatitis) was 9.9 per cent in placebo recipients and 2.2 per cent in vaccine recipients (P less than 0.01). The two cases of hepatitis B among vaccine recipients did not occur in subjects in whom antibody had developed. In 81 per cent of the hepatitis events, the virus was of the ay subtype. The indicence of ay virus was 8.2 per cent among placebo recipients and 1.2 per cent among vaccine recipients (P less than 0.005). We conclude that these data confirm the efficacy of the vaccine and demonstrate subtype cross-protection.

The immune response of healthy adults to a reduced dose of hepatitis B vaccine

Three hundred thirty-six medical personnel from hemodialysis centers were treated with three doses, 20 microgram each, of the Merck hepatitis B vaccine (at 0, 1, and 6 months). Within 1 month after the first injection, 41% converted to anti-HBs positivity; after the second injection the conversion rate rose to 80-90%; and after the booster, to 96-98%. The later rate remained unchanged during the 18-month follow-up period. Only 2.8% of those vaccinated did not respond to the vaccine. The patterns of immune responses to 20-microgram doses were found to be exactly the same as to 40-microgram doses. It is suggested that reduced doses of vaccine should be as efficacious as the larger ones.

WHO collaborative evaluation of reference hepatitis B surface antigen and antibody reagents, subtype ad

As a result of a WHO consultation in 1970 a guinea-pig antiserum, V801-501-058, was comprehensively evaluated by 11 collaborating laboratories in order to determine its usefulness as a reference reagent for the detection and assay of hepatitis B surface antigen (HB(s)Ag). The range of titres obtained were 1:64-1:256 by the immunodiffusion technique, 1:64-1:512 by counterimmunoelectrophoresis, 1:256-1:4096 by complement fixation, 1:6400-1:9600 by immune adherence haemagglutination, and <1:32 by platelet aggregation. The sensitivity of the guinea-pig antiserum for the detection of HB(s)Ag in serum and plasma samples was found to be equivalent to that of antisera obtained from other sources (man and baboon) with complement fixation and immune adherence haemagglutination, but it was slightly less sensitive with immunodiffusion and counterimmunoelectrophoresis. HB(s)Ag-positive reagent serum, which was used for the preparation of the immunogen, was found to have titres of 1:16-1:64 by immunodiffusion, 1:32-1:128 by counterimmunoelectrophoresis, 1:512-1:4096 by complement fixation, and 1:256-1:25 600 by immune adherence haemagglutination.