Cytokine responses of peripheral blood mononuclear cells to allergen do not identify asthma or asthma phenotypes.

BACKGROUND: Asthmatic patients are often differentiated based on their atopic status (atopic or nonatopic) and type of bronchitis (eosinophilic, neutrophilic, both, or neither). There is evidence supporting a central role for the T cell in asthma, but the role of allergen-induced T cell cytokines in driving disease in different asthma phenotypes remains unclear. OBJECTIVE: To investigate the hypothesis that peripheral blood mononuclear cells (PBMCs) from asthma patients with different phenotypes would react characteristically to a panel of common aeroallergens. METHODS: We incubated PBMCs from 41 asthma patients and 8 healthy controls with allergen and assessed PBMC proliferation by (3) H-thymidine incorporation and the production of the cytokines IL-5, IL-17A, IL-23, IL-10, and IFN-γ by ELISA. RESULTS: No differences in PBMC proliferation or cytokine production were found in patients with asthma, compared with healthy controls, or between patients with different asthma phenotypes. CONCLUSIONS AND CLINICAL RELEVANCE: Peripheral blood mononuclear cell cytokine responses to allergen are not able to assist in the discrimination between disease state, atopic status, or type of bronchitis in asthma.

Barriers to gender-equitable HIV testing: going beyond routine screening for pregnant women in Nova Scotia, Canada.

BACKGROUND: Women and men face different gender-based health inequities in relation to HIV, including HIV testing as well as different challenges in accessing HIV care, treatment and support programs and services when testing HIV-positive. In this article, we discuss the findings of a mixed methods study exploring the various individual and structural barriers and facilitators to HIV counselling and testing experienced among a sample of adult women and men living in Nova Scotia, Canada. METHODS: Drawing from testing demographics, qualitative interview data and a review of existing testing policies and research, this paper focuses on understanding the gendered health inequities and their implications for HIV testing rates and behaviours in Nova Scotia. RESULTS: The findings of this research serve as the basis to further our understanding of gender as a key determinant of health in relation to HIV testing. Recognizing gender as a key determinant of health in terms of both vulnerability to HIV and access to testing, this paper explores how gender intersects with health equity issues such as access to HIV testing, stigma and discrimination, and sexual behaviours and relationships. CONCLUSIONS: Drawing on the current gender and HIV literatures, in conjunction with our data, we argue that an enhanced, gender-based, context-dependent approach to HIV counselling and testing service provision is required in order to address the health equity needs of diverse groups of women and men living in various settings. Further, we argue that enhanced HIV testing efforts must be inclusive of both men and women, addressing uniquely gendered barriers to accessing HIV counselling and testing services and in the process moving beyond routine HIV testing for pregnant women.

Origins of cheating and loss of symbiosis in wild Bradyrhizobium.

Rhizobial bacteria nodulate legume roots and fix nitrogen in exchange for photosynthates. These symbionts are infectiously acquired from the environment and in such cases selection models predict evolutionary spread of uncooperative mutants. Uncooperative rhizobia - including nonfixing and non-nodulating strains - appear common in agriculture, yet their population biology and origins remain unknown in natural soils. Here, a phylogenetically broad sample of 62 wild-collected rhizobial isolates was experimentally inoculated onto Lotus strigosus to assess their nodulation ability and effects on host growth. A cheater strain was discovered that proliferated in host tissue while offering no benefit; its fitness was superior to that of beneficial strains. Phylogenetic reconstruction of Bradyrhizobium rDNA and transmissible symbiosis-island loci suggest that the cheater evolved via symbiotic gene transfer. Many strains were also identified that failed to nodulate L. strigosus, and it appears that nodulation ability on this host has been recurrently lost in the symbiont population. This is the first study to reveal the adaptive nature of rhizobial cheating and to trace the evolutionary origins of uncooperative rhizobial mutants.

HIV counselling and testing in Nova Scotia: the provincial strategy in the context of an international debate.

Nova Scotia, as a small province in Atlantic Canada, provides health care professionals and policy analysts with unique challenges for developing and implementing a strategy for accessible and acceptable HIV counselling and testing. Despite universal health care in Canada, barriers and challenges persist in relation to HIV counselling and testing programs and services in Nova Scotia. It is therefore necessary to examine the unique circumstances in the provision of programs and services in Nova Scotia prior to the possibility of adopting international HIV counselling and testing standards and guidelines being implemented in other jurisdictions. Nova Scotia's provincial strategy on HIV/AIDS promotes a harm-reduction approach for different populations in various service settings, recognizing the diverse circumstances and experiences of people living in Nova Scotia. By contrast, the Centers for Disease Control (CDC) recommended strategy promotes opt-out testing and in some instances alters the requirement of informed consent. As the Public Health Agency of Canada (PHAC) revises the national HIV counselling and testing policies, it is imperative to address the unique characteristics of Nova Scotia's provision of services, and how divergent strategies have the potential to address or compound the barriers to access that exist in this province's communities.

In situ phylogenetic structure and diversity of wild Bradyrhizobium communities.

Bacteria often infect their hosts from environmental sources, but little is known about how environmental and host-infecting populations are related. Here, phylogenetic clustering and diversity were investigated in a natural community of rhizobial bacteria from the genus Bradyrhizobium. These bacteria live in the soil and also form beneficial root nodule symbioses with legumes, including those in the genus Lotus. Two hundred eighty pure cultures of Bradyrhizobium bacteria were isolated and genotyped from wild hosts, including Lotus angustissimus, Lotus heermannii, Lotus micranthus, and Lotus strigosus. Bacteria were cultured directly from symbiotic nodules and from two microenvironments on the soil-root interface: root tips and mature (old) root surfaces. Bayesian phylogenies of Bradyrhizobium isolates were reconstructed using the internal transcribed spacer (ITS), and the structure of phylogenetic relatedness among bacteria was examined by host species and microenvironment. Inoculation assays were performed to confirm the nodulation status of a subset of isolates. Most recovered rhizobial genotypes were unique and found only in root surface communities, where little bacterial population genetic structure was detected among hosts. Conversely, most nodule isolates could be classified into several related, hyper-abundant genotypes that were phylogenetically clustered within host species. This pattern suggests that host infection provides ample rewards to symbiotic bacteria but that host specificity can strongly structure only a small subset of the rhizobial community.

Highly elevated PSA and dietary PhIP intake in a prospective clinic-based study among African Americans.

African-American men die from prostate cancer (PC) nearly twice as often as white US men and consume about twice as much of the predominant US dietary heterocyclic amine, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), a genotoxic rat-prostate carcinogen found primarily in well-cooked chicken and beef. To investigate the hypothesis that PhIP exposure increases PC risk, an ongoing prospective clinic-based study compared PC screening outcomes with survey-based estimates of dietary PhIP intake among 40-70-year-old African-American men with no prior PC in Oakland, CA. They completed food-frequency and meat-cooking/consumption questionnaires and had a prostate-specific antigen (PSA) test and digital-rectal exam. Results for 392 men indicated a 17 (+/-17) ng/kg day mean (+/-1 s.d.) daily intake of PhIP, about twice that of white US men of similar age. PhIP intake was attributable mostly to chicken (61%) and positively associated (R(2)=0.32, P<0.0001) with saturated fat intake. An odds ratio (95% confidence interval) of 31 (3.1-690) for highly elevated PSA > or =20 ng/ml was observed in the highest 15% vs lowest 50% of estimated daily PhIP intake (> or =30 vs < or =10 ng/kg day) among men 50+ years old (P=0.0002 for trend) and remained significant after adjustment for self-reported family history of (brother or father) PC, saturated fat intake and total energy intake. PSA measures were higher in African-American men with positive family history (P=0.007 all men, P<0.0001 highest PSA quartile). These preliminary results are consistent with a positive association between PhIP intake and highly elevated PSA, supporting the hypothesis that dietary intervention may help reduce PC risk.

The effect of nitrogen and phosphorus addition on the growth, reproduction, and nutrient dynamics of two ericaceous shrubs.

Aboveground growth, reproduction, and foliar nitrogen and phosphorus contents of two ericaceous shrub species were compared over two seasons in (a) an undisturbed shrub bog (pocosin), and (b) a factorial fertilization design in which three levels each of nitrogen and phosphorus were added in all possible combinations. One species, Zenobia pulverulenta, is deciduous whereas the other species, Lyonia lucida, is evergreen. In the nutrient-poor undisturbed pocosin the two species exhibited similar foliar nitrogen and phosphorus concentrations and aboveground growth rates. Neither species flowered. In response to nutrient-addition Zenobia increased growth rates more than Lyonia. Foliar phosphorus concentrations of both species increased in response to enhanced phosphorus availability. in the first season neither species flowered in any treatment. In the second season Zenobia flowered only in the fertilized plots, with the most flowering in the high phosphorus treatments. I conclude that, by virtue of high growth rates and efficient use of nutrients and despite differences in leaf phenology and morphology, both Lyonia and Zenobia are successful in a competitive community under conditions of extremely low phosphorus availability. However, unlike Lyonia, Zenobia can take advantage of temporarily increased nutrient availability, which occurs following fire in the pocosin, to increase growth and reproduction.

Severe combined immunodeficiency: otolaryngological presentation and management.

In order to increase the awareness of otolaryngologists of severe combined immunodeficiency syndrome (SCIDS) so they may contribute to an earlier diagnosis of this disorder, we performed a retrospective chart review of a multicenter series from 2 children's hospital medical centers. Eighteen cases were identified, and 14 had an otolaryngological presentation. The average age of presentation was 3.3 months, and 72% were males. Most cases were inherited in an X-linked fashion. Five patients had thrush; 4 had recurrent otitis media. Other otolaryngological presentations included cough, mouth ulcers, pharyngitis, mastoiditis, and bilateral neck abscess. The most severe form of immunodeficiency, SCIDS is a rare condition that involves a disorder in both T and B cell functions. The manifestations involving the head and neck include recurrent upper respiratory tract infections, otitis media, thrush, oral ulcers, and abscesses. It is important that SCIDS be considered in any infant with recurrences of these common infections.

Acquisition of hearing aids and assistive listening devices among the pediatric hearing-impaired population.

Sufficient access to health care is of concern to the indigent population in the US and to their health care providers. This study was undertaken to elucidate the rate of the follow-up among lower socioeconomic hearing-impaired pediatric patients who had received a recommendation for hearing aids and/or assistive listening devices. Our question was, would the families' financial situation have a negative effect on the acquisition of hearing aids and assistive listening devices? Fifty patients, age 0-18 years, who had been seen in our clinic over 2 years were evaluated via a telephone survey. The survey consisted of seven questions, including whether or not the devices or aids were obtained, what type was purchased, where the device was being used, and the child's apparent performance with the device. Eighty-two percent of our patients were on TennCare, a state mandated Medicaid HMO system. Two-thirds of these TennCare patients are at or below the poverty level and the remaining one-third is either disabled or uninsurable according to the Aid for Dependent Children (AFDC) with indeterminate income. In addition the TennCare organization did not cover hearing amplification equipment for these children. The study showed that the majority of the patients did follow-up as recommended. Furthermore, this equipment is easily obtainable for the pediatric indigent population due to financial resources available in the community outside the mandated Medicaid system.

Laparoscopy for the impalpable testes. Initial experience of one center.

Twenty three patients with impalpable tests underwent diagnostic laparoscopy in our hospital between 1988 and 1991, in an attempt to evaluate this modality of investigation. Four of them had bilateral undescended, i.e. total of 27 tests, 12 on the right side and 15 on the left. Eight patients were adults, age between 23 and 38, average 30 years, 15 were children, age between 1 and 9, average 5 years. Twenty testes were intraperitoneal (74%), 6 intracanalicular (22.2%) and one absent (3.8%). Thirteen testes were removed and 2 were diagnostic only, the rest had successful orchiopexy. No operative or postoperative morbidity. Laparoscopy was diagnostic in all cases, assisted in planning the surgical procedure in 21 testes and saved one patient the surgical incision. Laparoscopy is a safe procedure, has a definite role in the management of impalpable testes, for diagnosis and planning of surgery. Future prospects of operative laparoscopy needs to be developed and evaluated.

The test-retest reliability of a standardized neurocognitive and neurophysiological test battery: "neuromarker".

NeuroMarker combines EEG and ERP measures with neurocognitive tests in a fully computerized and standardized testing system. It is designed for use across the lifespan and has a large normative database of over 1,000 subjects. This study was a preliminary evaluation of "NeuroMarker" in subjects spanning four decades. Twenty-one healthy subjects (12-57 years) were tested at baseline and four weeks later. From the "Neuromarker" battery, the authors analyzed EEG data (eyes open and closed) and ERPs elicited during auditory oddball (N100, P200, N200, P300) and working memory (P150, P300) tasks. Concomitant neuropsychological data, acquired using a touch-screen system, comprised measures of sensori-motor, attention, verbal, executive, and memory function. Test-retest data were examined using analyses of variance and correlational procedures (corrected for multiple comparisons), with parallel analyses of age. EEG data did not differ across sessions, and showed high test-retest reliability (.71-.95), particularly for theta and delta (>.85). ERP components also showed sound reliability, particularly for sites where components are maximal: fronto-central N100 (.76-.77), centro-parietal P300 (.78-.81) to oddball targets, N100 and P200 (.74-.86) to oddball non-targets, and P150 amplitude and latency (.84-.93) to working memory stimuli. Neuropsychological tests showed a similarly sound level of consistency (on average, .70), with the most consistent tests tapping simple motor function, estimated intelligence, switching of attention (Part 2), verbal interference response time and memory intrusions (.71-.89). Age and sex did not have a differential impact on reliability for EEG, ERP, or neuropsychology measures. These findings provide preliminary evidence that the "NeuroMarker" battery is reliable for test-retest assessments. The results suggest that the standardized approach has utility for providing sensitive clinical and treatment evaluations across age groups.

Two books in one: natural history and evolutionary theory.

Evolutionary Ecology across Three Trophic Levels: Goldenrods, Gallmakers and Natural Enemies by W.G. Abrahamson and A.E. Weis Princeton University Press, Monographs in Population Biology, 1997. $29.95/£24.95 hbk (xiii+456 pages) ISBN 0 691 01208 3.

Immune responses in mice infected with lactic dehydrogenase virus. IV. Functional status of the macrophage during acute LDV infection.

Macrophages from uninfected and lactic dehydrogenase virus (LDV)-infected mice were compared with respect to the affinity and number of their Fc receptors for IgG2a; no differences were found regarding these parameters. When the uptake of DNP-BGG by macrophages from uninfected and acutely LDV-infected mice was compared, again no differences were observed. However, when the per cent membrane-bound DNP-BGG was determined as a function of time after antigen uptake in these two groups, more DNP-BGG was found membrane-bound on the macrophages from the LDV-infected mice, than on uninfected macrophages. In view of the fact that humoral immunity is enhanced during acute LDV infection, these data provide a positive correlation between increased retention of membrane-bound antigen and enhanced humoral immune responses.

Immune responses in mice infected with lactic dehydrogenase virus. I. Antibody response to DNP-BGG and hyperglobulinaemia in BALB/c mice.

The humoral immune response to DNP-BGG of BALB/c mice acutely infected with lactic dehydrogenase virus (LDV) has been investigated. Virus-infected mice injected with antigen in saline exhibit a greater anti-DNP response than uninfected controls. When this antigen is presented in Freund's complete adjuvant (FCA) the anti-DNP response is greater than obtained with antigen in saline, but significant differences between infected and uninfected controls are not observed. These data are consistent with the view that acute LDV infection can have an adjuvant-like effect when this T-dependent antigen is introduced in saline. In addition, the effect of viral infection on plasma Ig class and subclass levels has been investigated. LDV infection leads to a gradual increase in plasma Ig concentration. This effect is restricted to the IgG2a subclass in most animals, but occasionally is restricted to IgG1. The mechanisms responsible for these changes have not been delineated.

The ecology and evolution of host-plant resistance to insects.

Genetic techniques have yielded new insights into plant-herbivore coevolution. Quantitative genetic tests of herbivory theory reveal that in some cases insect herbivores impose selection on resistance traits. Also, some resistance traits are costly while others appear not to be, and genetic models can explain these results. Genetic variation in plant resistance influences insect community structure by modifying interactions of herbivores with competitors and natural enemies. Therefore, models of multispecies coevolution are more realistic than pairwise coevolutionary models. Ecological genetics will facilitate further theoretical and empirical exploration of multispecies coevolution of plants and herbivores.