Diversity Of Subpopulations Research Articles

Molecular diversity and population structure of Chinese green foxtail [Setaria viridis (L.) Beauv.] revealed by microsatellite analysis.

Green foxtail (Setaria viridis) is a new model plant for the genomic investigation of C4 photosynthesis biology. As the ancestor of foxtail millet (Setaria italica), an ancient cereal of great importance in arid regions of the world, green foxtail is crucial for the study of domestication and evolution of this ancient crop. In the present study, 288 green foxtail accessions, which were collected from all geographical regions of China, were analysed using 77 simple sequence repeats (SSRs) that cover the whole genome. A high degree of molecular diversity was detected in these accessions, with an average of 33.5 alleles per locus. Two clusters, which were inconsistent with the distribution of eco-geographical regions in China, were inferred from STRUCTURE, Neighbor–Joining, and principal component analysis, indicating a partially mixed distribution of Chinese green foxtails. The higher subpopulation diversity was from accessions mainly collected from North China. A low level of linkage disequilibrium was observed in the green foxtail genome. Furthermore, a combined analysis of green foxtail and foxtail millet landraces was conducted, and the origin and domestication of foxtail millet was inferred in North China.

Psychometric Properties of an HIV Knowledge Scale Administered With Populations at High Risk for HIV Infection

HIV prevention programs targeting men who have sex with men, Blacks, and young adults commonly use measures of HIV knowledge as an important component of demonstrating overall program effectiveness. These scales, however, are rarely subjected to repeated analysis to confirm reliability and validity and the results of psychometric analysis rarely include subpopulation variations. In this study, we administered an adapted version of a previously validated HIV knowledge scale to participants of a large, city-wide HIV prevention program (n = 5,027) and performed psychometric analysis to determine if differences existed across populations. Analysis showed that the HIV knowledge scale performed poorly for men who have sex with men, but very well for transgenders. Results were similar for Blacks, Hispanics, and Whites, very poor for 30- to 39-year-olds, but very well for 60+ year olds. Findings underscore the need for further research on the measurement of HIV knowledge among high-risk populations and the importance of culturally appropriate survey items tailored to each population.

A phosphatidylinositol 3-kinase-Pax3 axis regulates Brn-2 expression in melanoma.

Deregulation of transcription arising from mutations in key signaling pathways is a hallmark of cancer. In melanoma, the most aggressive and lethal form of skin cancer, the Brn-2 transcription factor (POU3F2) regulates proliferation and invasiveness and lies downstream from mitogen-activated protein kinase (MAPK) and Wnt/β-catenin, two melanoma-associated signaling pathways. In vivo Brn-2 represses expression of the microphthalmia-associated transcription factor, MITF, to drive cells to a more stem cell-like and invasive phenotype. Given the key role of Brn-2 in regulating melanoma biology, understanding the signaling pathways that drive Brn-2 expression is an important issue. Here, we show that inhibition of phosphatidylinositol 3-kinase (PI3K) signaling reduces invasiveness of melanoma cells in culture and strongly inhibits Brn-2 expression. Pax3, a transcription factor regulating melanocyte lineage-specific genes, directly binds and regulates the Brn-2 promoter, and Pax3 expression is also decreased upon PI3K inhibition. Collectively, our results highlight a crucial role for PI3K in regulating Brn-2 and Pax3 expression, reveal a mechanism by which PI3K can regulate invasiveness, and imply that PI3K signaling is a key determinant of melanoma subpopulation diversity. Together with our previous work, the results presented here now place Brn-2 downstream of three melanoma-associated signaling pathways.

FGF2 deficit during development leads to specific neuronal cell loss in the enteric nervous system

The largest part of the peripheral nervous system is the enteric nervous system (ENS). It consists of an intricate network of several enteric neuronal subclasses with distinct phenotypes and functions within the gut wall. The generation of these enteric phenotypes is dependent upon appropriate neurotrophic support during development. Glial cell line-derived neurotrophic factor (GDNF) and fibroblast growth factor-2 (FGF2) play an important role in the differentiation and function of the ENS. A lack of GDNF or its receptor (Ret) causes intestinal aganglionosis in mice, while fibroblast growth factor receptor signaling antagonist is identified as regulating proteins in the GDNF/Ret signaling in the developing ENS. Primary myenteric plexus cultures and wholemount preparations of wild type (WT) and FGF2-knockout mice were used to analyze distinct enteric subpopulations. Fractal dimension (D) as a measure of self-similarity is an excellent tool to analyze complex geometric shape and was applied to classify the subclasses of enteric neurons concerning their individual morphology. As a consequence of a detailed analysis of subpopulation variations, wholemount preparations were stained for the calcium binding proteins calbindin and calretinin. The fractal analysis showed a reliable consistence of subgroups with different fractal dimensions (D) in each culture investigated. Seven different neuronal subtypes could be differentiated according to a rising D. Within the same D, the neurite length revealed significant differences between wild type and FGF2-knockout cultures, while the subclass distribution was also altered. Depending on the morphological characteristics, the reduced subgroup was supposed to be a secretomotor neuronal type, which could be confirmed by calbindin and calretinin staining of the wholemount preparations. These revealed a reduction up to 40% of calbindin-positive neurons in the FGF2-knockout mouse. We therefore consider FGF2 playing a more important role in the fine-tuning of the ENS during development as previously assumed.

Genetic Diversity and Population Structure of Chinese Foxtail Millet [Setaria italica(L.) Beauv.] Landraces

As an ancient cereal of great importance for dryland agriculture even today, foxtail millet (Setaria italica) is fast becoming a new plant genomic model crop. A genotypic analysis of 250 foxtail millet landraces, which represent 1% of foxtail millet germplasm kept in the Chinese National Gene Bank (CNGB), was conducted with 77 SSRs covering the foxtail millet genome. A high degree of molecular diversity among the landraces was found, with an average of 20.9 alleles per locus detected. STRUCTURE, neighbor-jointing, and principal components analyses classify the accessions into three clusters (topmost hierarchy) and, ultimately, four conservative subgroups (substructuring within the topmost clusters) in total, which are in good accordance with eco-geographical distribution in China. The highest subpopulation diversity was identified in the accessions of Pop3 from the middle regions of the Yellow River, followed by accessions in Pop1 from the downstream regions of the Yellow River, suggesting that foxtail millet was domesticated in the Yellow River drainage area first and then spread to other parts of the country. Linkage disequilibrium (LD) decay of less than 20 cM of genetic distance in the foxtail millet landrace genome was observed, which suggests that it could be possible to achieve resolution down to the 20 cM level for association mapping.

Diagnostic Testing for Vaccinomics: Is the Regulatory Approval Framework Adequate? A Comparison of Canada, the United States, and Europe

Vaccinomics aims to integrate variability information from multiple levels of the biological hierarchy from genome to proteome to metabolome, and ways in which these biological parts interact with each other and the environment. Vaccinomics holds significant promise as a new public health tool in designing safer and more effective vaccines for both developed and developing countries. Vaccinomics tests that are envisioned to be used in tandem with vaccine-based health interventions could permit an informed forecast of individual and subpopulation variations in immune responses to vaccines, reduce adverse effects, and contribute to a foundation for rational and directed use of vaccines. A proactive, multidisciplinary engagement with vaccinomics is now timely and much needed in order to develop regulations that best ensure the protection of the public and promote the transition of vaccinomics innovations from discovery to real-life public health applications. This article examines and compares the regulatory oversight of vaccinomics tests in Canada, the United States, and Europe. Recent trends in these jurisdictions suggest that regulatory agencies view personalized genomics/omics medicine, such as vaccinomics, as a desirable goal. At the same time, proposals to increase oversight could impact progress in the field and affect the availability of vaccinomics tests in public health practice and the diagnostic test market. The comparative analysis of vaccinomics in three jurisdictions presented in this article highlights both the convergence and divergence of regulatory oversight. In a rapidly emerging field such as vaccinomics that is pivotal for global public health, achieving better harmonization of policies may be an advantageous target, while ensuring that symmetry exists between the goals of public safety and promoting public health innovation. We suggest it is now timely to proactively initiate a constructive dialogue among all stakeholders (publics, policymakers, researchers, private sector, governments) to foster the development of appropriately targeted regulatory policies in this field.

The human variome: genomic and epigenomic diversity

Work from the HUGO Pan-Asian Single Nucleotide Polymorphism (SNP) consortium has mapped human genetic diversity in different subpopulations in Asia (Abdulla et al, 2009). Now this highlights the question whether disease-SNP associations identified by genome-wide association studies (GWAS) in one subpopulation can be applied to other subpopulations or whether separate GWAS should be considered for different subpopulations because of their different SNP distributions (Haiman & Stram, 2010). DNA methylation is an epigenetic mark in the mammalian genome. ‘Epigenetic diversity’ encompasses variation in DNA methylation and like ‘genetic diversity’, ‘epigenetic diversity’ may also co-vary with phenotype (Feinberg et al, 2010). Mechanistically, disease-associated SNPs may be found in DNA regulatory regions where the genetic variation affects cognate binding of transcription factor complexes, effecting on the expression of disease-relevant genes (Harismendy et al, 2011). Similarly, variation in the methylation of a DNA regulatory region (either increased or decreased methylation) can also alter the binding of transcription factor complexes and regulate both distal and proximal gene expression (Choy et al, 2010; Jones & Takai, 2001; Phillips & Corces, 2009; Weaver et al, 2004). The availability of genome-wide maps of DNA methylation (Choy et al, 2010; Down et al, 2008; Lister et al, 2009) led us to examine whether a relationship exists between DNA methylation and regions of heterogeneous genetic variation. The Fixation Index (Fst) is a measure of fixation rate of SNP between two subpopulations. SNPs with high Fst are ones with more heterogeneity in a subpopulation compared to another. Using DNA methylation maps that were generated from individuals of European ancestry, we made the interesting discovery that high Fst-SNPs (Duan et al, 2008) (N = 8751) from European ancestry showed an aggregate methylation density pattern of modulation centred on SNPs compared to flanks of the SNPs (Fig 1). Methylation maps from Europeans showed density modulation only at sites of European high Fst-SNPs (i.e. high Fst-SNPs for European vs. African + European vs. Asian), but not sites of Asian or African high Fst-SNPs (i.e. high Fst-SNPs for Asian vs. European; or African vs. European, Fig 1). Similarly aggregate methylation density modulation was also absent in a negative control set of randomly selected SNPs (N = 8000). On the basis that increased DNA methylation may be a means of regulating transcription factor complex binding and therefore mark genomic regions that are important to control by methylation (Choy et al, 2010; Jones & Takai, 2001), our findings support the notion that sites of heterogeneous genetic variation in one subpopulation are functionally relevant to the corresponding subpopulation, but sites of heterogeneous genetic variation of a different subpopulation, are not. Figure 1 Methylation density across sites of SNPs This is consistent with the need to consider subpopulation differences in genetic variation when studying disease-SNP association. By extension, we propose that the epigenomes of subpopulations should also be considered as the International Human Epigenome Consortium gears up to generate 1000 reference epigenomes (Beck, 2010). Subpopulation differences will be important when drawing conclusions from associations between disease and the human variome.

Phylum-targeted pyrosequencing reveals diverse planctomycete populations in a eutrophic lake

Although populations of planctomycete bacteria are nearly ubiquitous in aquatic habitats, we lack a detailed understanding of their diversity and structure. This is due to difficulty in obtaining cultured representatives, but also to low recovery rates for planctomycete 16S rRNA genes when universal PCR primers are employed for sequencing studies. In an attempt to expand re - coverable planctomycete diversity, we investigated the use of primers targeting the Planctomycetes phylum. Planctomycete populations present during an algal bloom in a eutrophic lake were charac- terized by clone library sequencing and pyrosequencing of 16S rRNA genes, using planctomycete- targeted primers. We analyzed samples recovered from the sediment, water column, and algal mats within the lake's littoral zone. Sequences related to 9 planctomycete genera were identified within the 6287 planctomycete sequences and 1730 operational taxonomic units (OTUs) recovered. We observed variation in the specificity of the planctomycete primers, with more non-planctomycete sequences recovered through pyrosequencing than through cloning-based sequencing. Neverthe- less, the results of our study suggest that phylum-targeted pyrosequencing is a useful tool for better describing the diversity of bacterial sub-populations. This methodology could be employed for future testing of hypotheses regarding spatial and temporal differences in planctomycete diversity and abundance. Candidate hypotheses arising from this preliminary study include (1) members of certain planctomycete genera (particularly Rhodopirellula) are enriched in algal mats relative to other planc- tomycete genera; (2) sediments harbor the most diverse planctomycete populations; and (3) most planctomycete OTUs are not shared between lake habitats.

Molecular and morphological analyses of date palm (Phoenix dactylifera L.) subpopulations in southern Tunisia

Phoenix dactylifera L. is widely distributed and performs an important socioeconomic role in the south of Tunisia.The objective of this work was to evaluate different methods of estimating the diversity and genetic structure of Tunisiandate palm subpopulations. Nine morphological traits and five SSR loci were used to study morphological and genetic diversity. Correlations between phenotypic and genetic distances were assessed. Analyses of variance of the morphological data reveal significant differences among subpopulations for all traits measured. The Mantel test shows that morphological variation is correlated with fruit maturity period (r = 0.161; p = 0.020). Analysis of molecular variance reveals significant genetic variation among fruit-consistency subpopulations (p < 0.05) and the Mantel test emphasises a correlation between genetic distance and fruit consistency (r = 0.110; p = 0.029). This information will be useful for germplasm collection, for conservation and for various date palm culture programmes in the Tunisian continental oases.

Multiple birthdating analyses in adult neurogenesis: a line-up of the usual suspects

Analyzing the variation in different subpopulations of newborn neurons is central to the study of adult hippocampal neurogenesis. The acclaimed working hypothesis that different subpopulations of newborn, differentiating neurons could be playing different roles arouses great interest. Therefore, the physiological and quantitative analysis of neuronal subpopulations at different ages is critical to studies of neurogenesis. Such approaches allow cells of different ages to be identified by labeling them according to their probable date of birth. Until very recently, only neurons born at one specific time point could be identified in each experimental animal. However the introduction of different immunohistochemically compatible markers now enables multiple subpopulations of newborn neurons to be analyzed in the same animal as in a line-up, revealing the relationships between these subpopulations in response to specific influences or conditions. This review summarizes the current research carried out using these techniques and outlines some of the key applications.

Phenotypic Variations in Chondrocyte Subpopulations and Their Response to In Vitro Culture and External Stimuli

Articular cartilage defects have limited capacity to self-repair, and cost society up to 60 billion dollars annually in both medical treatments and loss of working days. Recent developments in cartilage tissue engineering have resulted in many new products coming to market or entering clinical trials. However, there is a distinct lack of treatments which aim to recreate the complex zonal organization of articular cartilage. Cartilage tissue withstands repetitive strains throughout an individual's lifetime and provides frictionless movement between joints. The structure and composition of its intricately organized extracellular matrix varies with tissue depth to provide optimal resistance to loading, ensure ease of movement, and integrate with the subchondral bone. Each tissue zone is specially designed to resist the load it experiences, and maximize the tissue properties needed for its location. It is unlikely that a homogenous solution to tissue repair will be able to optimally restore the function of such a heterogeneous tissue. For zonal engineering of articular cartilage to become practical, maintenance of phenotypically stable zonal cell populations must be achieved. The chondrocyte phenotype varies considerably by zone, and it is the activity of these cells that help achieve the structural organization of the tissue. This review provides an examination of literature which has studied variations in cellular phenotype between cartilage zones. By doing so, we have identified critical differences between cell populations and highlighted areas of research which show potential in the field. Current research has made the morphological and metabolic variations between these cell populations clear, but an ideal way of maintaining these differences in vitro culture is yet to be established. Combinations of delivered growth factors, mechanical loading, and layered three-dimensional culture systems all show potential for achieving this goal. Furthermore, differentiation of progenitor cell populations into chondrocyte subpopulations may also hold promise for achieving large numbers of zonal chondrocytes. Success of the field lies in establishing methods of retaining phenotypically stable cell populations for in vitro culture.

Taking the heterogeneity of citizens into account: flood risk communication in coastal cities – a case study of Bremen

Abstract. The likely manifestations of climate change like flood hazards are prominent topics in public communication. This can be shown by media analysis and questionnaire data. However, in the case of flood risks an information gap remains resulting in misinformed citizens who probably will not perform the necessary protective actions when an emergency occurs. This paper examines more closely a newly developed approach to flood risk communication that takes the heterogeneity of citizens into account and aims to close this gap. The heterogeneity is analysed on the meso level regarding differences in residential situation as well as on the micro level with respect to risk perception and protective actions. Using the city of Bremen as a case study, empirical data from n=831 respondents were used to identify Action Types representing different states of readiness for protective actions in view of flood risks. These subpopulations can be provided with specific information to meet their heterogeneous needs for risk communication. A prototype of a computer-based information system is described that can produce and pass on such tailored information. However, such an approach to risk communication has to be complemented by meso level analysis which takes the social diversity of subpopulations into account. Social vulnerability is the crucial concept for understanding the distribution of resources and capacities among different social groups. We therefore recommend putting forums and organisations into place that can mediate between the state and its citizens.

Age, Growth, Mortality and Population Structure of Strombus canarium (Gastropoda: Strombidae): Variations in Male and Female Sub-Populations

The age, growth, mortality and population structure of Strombus canarium Linnaeus, 1758 were examined in the Johor Straits, Malaysia from January to December 2005. A total of 2088 conchs were sampled where females were more abundant than males with monthly sex ratio of 1.72±0.17 (N = 12). The estimated growth parameter showed higher asymptotic length (L∞) and growth coefficient (K) in females (L∞ = 70.20 mm, K = 1.50 year-1) compared with the males (L∞ = 69.30 mm, K = 1.20 year-1). This resulted in better overall growth performance of females (φ’ = 3.81) compared with the males (φ’ = 3.48). The growth pattern of females and males showed positive allometric nature of growth (b>3, p<0.05), with estimated maximum life span of 2.0 and 2.5 year, respectively. The recruitment pattern was continuous, displaying only a single major peak event per year. The estimated natural mortality rate (M) was 0.95 year-1 in females and 0.86 year-1 in males, while the total mortality rate (Z) was 2.56 and 2.72 year-1, respectively. The fishing mortality rate (F) was 1.61 year-1 in females and 1.86 year-1 in males, which were higher than the natural mortality rates, thus indicating an unbalanced position of the stock. In addition, the exploitation rate (E) was higher than the maximum allowable limit of exploitation (EMSY), which was a further indication of overexploitation. For sustainable utilization of the resource, serious efforts should immediately be taken in reducing the exploitation rates of S. canarium in the study area.

The effect of sub-culturing on the basal level of type I interferon (IFN) gene expression in the Salmon Head Kidney (SHK-1) cell line

Over sub-culturing a cell line generates a selective pressure which can result in key cellular functions being altered such as gene and protein expression. The present study set out to determine whether serial sub-culturing affects the antiviral state of the Salmon Head Kidney (SHK-1) cell line. Cells were cultured under constant conditions and real-time PCR was performed to measure the level of interferon (IFN) and Mx gene expression over different passage numbers. A significant increase in the basal level of IFN and Mx gene expression was recorded at passage number 58 (3 and 14-fold increase versus passage number 53), suggesting a sub-culturing effect on the type I IFN response in SHK-1 cells. Passage dependent variations in morphology and cell sub-populations have been previously observed in SHK-1 cells. Such variations in cell sub-types were suspected to be responsible for the fluctuations in IFN and Mx gene expression recorded in this study.

Theory driven research designs for explaining behavioural health risk transitions: The case of smoking

Recent social network analyses have suggested that common chronic disease risk factors are more mutable than expected; raising practical considerations for public health interventions. Within this context, it is timely to assess the alternative social science reasoning being offered to explain behavioural health risk transitions. This paper takes up this challenge by critically reviewing the major theories applied to the temporal trends and sub-population variations in affluent country smoking behaviour. Three explanations dominate: a materialist approach; Bourdieu's distinctive class-based cultures; and, the spread of norms and emotions within social networks. We note conceptual tension when integrated theories are adopted. We also report on the relative absence of theoretical interrogation for the persistent adoption of smoking behaviours among present and successive lower socio-economic status (SES) cohorts. While unequal rates of persistence within cohorts has received some attention, the ongoing adoption of a non-innovative and health damaging behaviour is not well understood. To this end, we suggest the incorporation of several underused concepts: namely Bourdieu's 'rules of the game' and 'symbolic violence' and 'mimesis', an aspect of social contagion. We conclude by describing the implications for social action of the alternative theories, and argue that theory driven research designs could deliver more efficacious evidence for interventions than the post hoc application of theories to existing data sets.

Low Genetic Variation in Subpopulations of an Endangered Clonal PlantIris sibiricain Southern Poland

The spatial genetic structure in three subpopulations of the endangered clonal plant Iris sibirica from southern Poland was investigated. The subpopulations occurred in different habitats, i.e. in a Molinietum caeruleae community, a Phragmites australis patch and in a willow brushwood. Using 13 enzymatic systems, sixteen loci were evaluated. The very low genetic diversity (P = 0%–18.7%, A = 1.0%–1.19%, Ho= 0.000–0.009) observed within the subpopulations is probably due to lack of recruitment, habitat fragmentation and/or historical causes. Five distinct multilocus genotypes, detected from 148 collected samples in the subpopulations, supported this observation. This fact illustrated that only clonal growth could maintain the present low genetic variation through the domination of a single or a few clones within these sites. Moderate genetic differentiation (FST = 0.077, P < 0.001) that varies strongly between pairs of subpopulations, was observed, thereby suggesting substantial gene flow between populations.

Frequent point of care monitoring demonstrates the safety of low intensity warfarin therapy in Asian patients with mechanical heart valve

Genetic variants of the main cytochrome P-450 (CYP) and ethnicity may influence warfarin dosing. Chinese patients are reportedly more sensitive than Caucasians to the anticoagulant effect of warfarin. The use of the Point of Care Testing (POCT) and frequent monitoring of the international normalization ratio (INR) had facilitated measurements of essential coagulation parameters of warfarin therapy. To our knowledge, POCT has not been evaluated in clinical trials that underlay ethnic differences between different geographic regions. We have conducted a multi-center prospective trial to evaluate the safety of low warfarin dose, and the role of frequent INR measurements by POCT in Chinese patients. A total of 488 patients from 11 geographically diverse hospitals in China underwent implantation with CarboMedics aortic or mitral valve prosthesis (Sulzer Medica, Austin, TX). Patients received two consecutive doses of 2.5 mg warfarin at 24 and 72 h post-surgery, followed by a daily dose to maintain INR range of 1.5–2.5. The follow-up was performed weekly or biweekly and the INR was measured on fingerstick fresh whole blood, using the HEMOCHRON Signature Microcoagulation system (ITC, NJ). The majority (99.3%) of Chinese patients who required prosthetic heart valve and warfarin therapy were \70 years old with a mean age of 45.28 ± 12. The mean follow-up duration was 86.8 ± 11.2 weeks (range 72–104 weeks). A total of 4,886 INR values were obtained with a mean INR in all 11 sites at 1.76 ± 0.50. The majority of INR values (67.8%, n = 3,312), was in therapeutic range (1.5–2.5), a moderate number was below range (26.2%, n = 1,281), whereas only 6.0% (n = 293) of INR value was above range. Mean daily maintenance dose was 2.5 ± 0.60 mg in all sites; a significant reduction from age-matched ACCP guideline for rest of the world (ROW) patients. Minor bleeding occurred in 42 cases, no patient required hospitalization. Major adverse events (4 cases) were lower than reported ROW data. The maintenance of antithrombotic efficacy with low warfarin requirement and narrow INR range in Chinese patients was independent of demographic factors and geographic locations. Frequent INR-POCT confirmed the safety of low dose warfarin requirements in Chinese patients. Monitoring by POCT may provide a mean to standardize warfarin monitoring across diverse geographic regions and therefore allow the analysis of ethnic variation in various subpopulations.

Functional Diversity of T-Cell Subpopulations in Subacute and Chronic Hypersensitivity Pneumonitis

Hypersensitivity pneumonitis (HP) exhibits a diverse outcome. Patients with acute/subacute HP usually improve, whereas patients with chronic disease often progress to fibrosis. However, the mechanisms underlying this difference are unknown. To examine the T-cell profile from patients with subacute HP and chronic HP. T cells were obtained by bronchoalveolar lavage from 25 patients with subacute HP, 30 patients with chronic HP, and 8 control subjects. T-cell phenotype and functional profile were evaluated by flow cytometry, cytometric bead array, and immunohistochemistry. Patients with chronic HP showed higher CD4+:CD8+ ratio (median, 3.05; range, 0.3-15; subacute HP: median, 1.3; range, 0.1-10; control: median, 1.3; range, 0.7-2.0; P < 0.01), and a decrease of gammadeltaT cells (median, 2.0; range, 0.5-3.4; subacute HP: median, 10; range, 4.8-17; control: median, 15; range, 5-19; P < 0.01). Patients with chronic HP exhibited an increase in the terminally differentiated memory CD4+ and CD8+ T-cell subsets compared with patients with subacute HP (P < 0.05). However, memory cells from chronic HP showed lower IFN-gamma production and decreased cytotoxic activity by CD8+ T lymphocytes. Chronic HP displayed a Th2-like phenotype with increased CXCR4 expression (median, 6%; range, 1.7-36, vs. control subjects: median, 0.7%; range, 0.2-1.4; and subacute HP: median, 2.2%; range, 0.1-5.3; P < 0.01), and decreased CXCR3 expression (median, 4.3%; range, 1.4-25%, vs. subacute HP: median, 37%; range, 4.9-78%; P < 0.01). Likewise, supernatants from antigen-specific-stimulated cells from chronic HP produced higher levels of IL-4 (80 +/- 63 pg/ml vs. 25 +/- 7 pg/ml; P < 0.01), and lower levels of IFN-gamma (3,818 +/- 1671 pg/ml vs. 100 +/- 61 pg/ml; P < 0.01) compared with subacute HP. Our findings indicate that patients with chronic HP lose effector T-cell function and exhibit skewing toward Th2 activity, which may be implicated in the fibrotic response that characterizes this clinical form.

Gene expression of single articular chondrocytes

Although previous studies in the field of tissue engineering have provided important information about articular cartilage, their conclusions are based on population averages and do not account for variations in cell subpopulations. To obtain a precise understanding of chondrocytes, we investigated the effects of cartilage zone and seeding duration on single chondrocyte gene expression to select an optimal zone for tissue engineering (Phase I), followed by an evaluation of growth factor exposure on the zone selected in Phase I (Phase II). In Phase I, superficial and middle/deep bovine articular chondrocytes were seeded in monolayers for 3 or 18 h. In Phase II, middle/deep chondrocytes (selected in Phase I) received 100 ng/ml insulin-like growth factor-I (IGF-I) for 3 h. Real-time reverse transcription/polymerase chain reaction was used to quantify the abundance of D-glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and the relative abundances of aggrecan, collagens I and II, cartilage oligomeric matrix protein (COMP), matrix metalloproteinase-1 (MMP-1), and tissue inhibitor of metalloproteinase-1 (TIMP-1). GAPDH varied zonally, but neither time nor IGF-I had an effect on it, suggesting that GAPDH is a suitable housekeeping gene for comparisons within each zone, but not across zones. IGF-I increased the expression of aggrecan and collagen II in middle/deep chondrocytes seeded for 18 h. TIMP-1 expression increased with time in control cells, suggesting that chondrocytes enter a matrix protective state after seeding. IGF-I diminished this effect, suggesting that treatment with IGF-I refocuses chondrocytes on matrix production rather than on protection from metalloproteinases. Concomitant to increasing TIMP-1, MMP-1 was detectable by 18 h in superficial cells, providing further evidence of a trend toward matrix degradation with time. Collagen I was undetected in all cells, and no differences were observed for COMP, confirming that no dedifferentiation or osteoarthritic changes occurred. Taken together, these results establish a unique understanding of individual chondrocyte behavior.

Genetic diversity in managed subpopulations of Norway spruce [ Picea abies (L.) Karst.

Uniparentally inherited chloroplast simple sequence repeats (cpSSRs), mitochondrial markers (mt), as well as biparentally inherited nuclear simple sequence repeats (SSRs) were used to analyse genetic diversity in different subpopulations of Norway spruce in Austria. For that purpose Norway spruce individuals of different age classes, old (70–100 years) versus young (6–10 years) trees, were fingerprinted to elucidate the genetic effects caused by human management. Three populations from different elevations were selected in a restricted area. Four hundred and fifty individuals, 50 old and 100 young trees from each population, were analysed for this study. Seven paternally inherited cpSSRs revealed no variation within and among populations. In contrast, analysis of three maternal mitochondrial markers showed variation in one locus in individuals originating from the high elevation sample set. Analysis of five polymorphic nuclear SSR loci revealed 135 different alleles. Nuclear SSRs results showed that there is generally more genetic variation and heterozygosity within populations than among populations. Populations from high elevation exhibit more genetic variation than samples from middle and low elevations.