Discrimination of MHC-derived odors by untrained mice is consistent with divergence in peptide-binding region residues

Genes of the major histocompatibility complex (MHC) play a central role in immune recognition, yet they also influence the odor of individuals. Mice can be trained to distinguish odors mediated by classical MHC loci; however, training can introduce confounding behavioral artifacts. This study demonstrates that mice can distinguish some, but not all, naturally occurring allelic variants at classical MHC loci without prior training. This result suggests that MHC-disassortative mating preferences might operate by means of small MHC-based odor differences, and could therefore contribute to diversifying selection acting on MHC loci. Here we show that odors of two MHC mutant mouse strains (bm1 and bm3) can be distinguished, even after genetic background is controlled by intercrossing strains. These two strains differ by five amino acids, three of which are predicted to chemically contact peptides bound to the peptide-binding region (PBR), the site of antigen presentation for T cell recognition. However, the odors of neither bm1 nor bm3 were distinguished from their parental B6 haplotype after randomizing genomic background, despite discrimination of pure-bred B6 and bm1 strain odors. These combined results suggest that (i) there may be an MHC odor discrimination threshold based on divergence in PBR residues, providing a more logical pattern of MHC-based odor discrimination than found in previous training studies, where discrimination ability was not correlated with PBR divergence; and (ii) additional (non-MHC) mutations that influence odor have accumulated in these strains during the 100 generations of divergence between pure B6 and bm1 strains.     

Accuracy of supplementary serologic testing for human T-lymphotropic virus types I and II in US blood donors. Retrovirus Epidemiology Donor Study

Blood donations in the United States have been screened for antibody to human T-lymphotropic virus type I (HTLV-I) by HTLV-I enzyme immunoassay (EIA) since November 1988. Specimens repeatedly found to be reactive by EIA undergo confirmation by supplementary serologic tests. We assessed the accuracy of blood center testing of 994 HTLV-I EIA repeat-reactive specimens in five US blood centers between November 1988 and December 1991. Of 410 confirmed HTLV-I/II donations, 407 (99.3%) were infected with HTLV-I/II, as determined by polymerase chain reaction (PCR) (403 cases) and by repeat serologic testing (4 cases). The three false- positive results occurred in the first year of testing. Of 425 HTLV- indeterminate specimens, 6 (1.4%) were found to be infected by PCR (5 with HTLV-II and 1 with HTLV-I). None of 159 confirmatory test-negative donations was PCR positive. Of HTLV-I/II-seropositive specimens, 80.2% to 95.4% could be typed as HTLV-I or HTLV-II by type-specific serologic assays. These results support recommendations that HTLV-I/II- seropositive donors should be advised that they are infected with HTLV- I, HTLV-II, or HTLV-I/II (depending on results of type-specific assays). HTLV-indeterminate donors should be advised that their results only rarely indicate HTLV infection. HTLV confirmatory test-negative donors should be reassured that they are not infected with HTLV-I or HTLV-II.     

Copy number variants in patients with short stature

Height is a highly heritable and classic polygenic trait. Recent genome-wide association studies (GWAS) have revealed that at least 180 genetic variants influence adult height. However, these variants explain only about 10% of the phenotypic variation in height. Genetic analysis of short individuals can lead to the discovery of novel rare gene defects with a large effect on growth. In an effort to identify novel genes associated with short stature, genome-wide analysis for copy number variants (CNVs), using single-nucleotide polymorphism arrays, in 162 patients (149 families) with short stature was performed. Segregation analysis was performed if possible, and genes in CNVs were compared with information from GWAS, gene expression in rodents'' growth plates and published information. CNVs were detected in 40 families. In six families, a known cause of short stature was found (SHOX deletion or duplication, IGF1R deletion), in two combined with a de novo potentially pathogenic CNV. Thirty-three families had one or more potentially pathogenic CNVs (n=40). In 24 of these families, segregation analysis could be performed, identifying three de novo CNVs and nine CNVs segregating with short stature. Four were located near loci associated with height in GWAS (ADAMTS17, TULP4, PRKG2/BMP3 and PAPPA). Besides six CNVs known to be causative for short stature, 40 CNVs with possible pathogenicity were identified. Segregation studies and bioinformatics analysis suggested various potential candidate genes.     

Tropical countries may be willing to pay more to protect their forests

Inadequate funding from developed countries has hampered international efforts to conserve biodiversity in tropical forests. We present two complementary research approaches that reveal a significant increase in public demand for conservation within tropical developing countries as those countries reach upper-middle-income (UMI) status. We highlight UMI tropical countries because they contain nearly four-fifths of tropical primary forests, which are rich in biodiversity and stored carbon. The first approach is a set of statistical analyses of various cross-country conservation indicators, which suggests that protective government policies have lagged behind the increase in public demand in these countries. The second approach is a case study from Malaysia, which reveals in a more integrated fashion the linkages from rising household income to increased household willingness to pay for conservation, nongovernmental organization activity, and delayed government action. Our findings suggest that domestic funding in UMI tropical countries can play a larger role in (i) closing the funding gap for tropical forest conservation, and (ii) paying for supplementary conservation actions linked to international payments for reduced greenhouse gas emissions from deforestation and forest degradation in tropical countries.Primary forests—“forests of native species in which there are no clearly visible signs of past or present human activity” (ref. 1, p. 11)—are globally significant repositories of biodiversity (2) and carbon (3). The global area of these forests is declining at an annual percentage rate that is nearly triple the rate for total global forest area (ref. 1, tables 2.4 and 3.3). Virtually all of the loss is occurring in tropical countries (SI Text, section 1). Logging is the main cause of the loss (ref. 1, p. 27), but hunting threatens biodiversity even in primary forests with intact tree cover (4, 5).Protecting primary tropical forests is a core mission of several international institutions created since the early 1990s, including the Convention on Biological Diversity (CBD), the Global Environment Facility (GEF), and the UN Collaborative Program on Reducing Emissions from Deforestation and Forest Degradation in Developing Countries (REDD). However, the CBD failed to achieve its goal of significantly reducing biodiversity loss by 2010 (6); international funding for biodiversity protection through the GEF and other mechanisms is below commitments made at the 1992 Earth Summit (7) and the amounts required to achieve the CBD’s 2020 protection targets (8); and REDD has not advanced beyond a readiness phase (www.un-redd.org). Relying on international mechanisms to fund protection of primary tropical forests does not look like a winning strategy.Here, we argue that economic development during the past 20–25 y has raised public demand for forest protection within tropical countries, but the level of protection supplied by tropical country governments has not kept pace. We focus on the dynamics of conservation and development within relatively wealthier developing countries: The group that is classified by the World Bank as upper-middle income (UMI). As we will show, the majority of primary forest area in tropical countries is found in these countries. We hypothesize that public willingness to pay (WTP) to protect forests has reached a relatively high level in UMI countries, leading to greater support for local conservation nongovernmental organizations (NGOs) and prompting governments to boost forest protection efforts—but not as much as the public would like. This gap between domestic demand and domestic supply of forest protection has two important implications: Domestic funding might be sufficient to cover the costs of additional protection in some, and perhaps many, tropical countries; and international funding might be able to leverage more domestic funding than it currently does.Although many cross-country studies in the environmental Kuznets curve (EKC) literature have investigated the effect of rising national income on deforestation (9), none has considered the effect on primary forests. This gap matters because deforestation, unlike primary forest loss, results mainly from agricultural conversion, not logging (1, 10). A few cross-country studies have considered the effect of national income on creation of protected areas (11–16), but with mixed findings on the significance of the effect. A second and larger group of studies has used surveys to measure WTP for biodiversity conservation by domestic populations within particular countries. Most of these studies have failed to detect a significant income effect (P < 0.05) (17, 18). Metaanalyses of these studies estimate income effects that are generally positive (protection increases with income) but not necessarily statistically significant (17, 18).We extended this prior work by coupling two research approaches: a broad-brush statistical analysis of the association between a standard measure of economic development, i.e., per capita gross national income (GNI), and a large set of cross-country conservation indicators (CIs); and a focused investigation of forest protection in a particular UMI country, Malaysia. The statistical analysis spanned 12 indicators from 10 diverse sources (Materials and Methods and SI Text, section 1). The indicators pertained to public environmental preferences, conservation NGOs, and government action (conservation spending, protected area establishment). These indicators relate more directly to our hypothesis about domestic demand and domestic supply of forest protection than do the deforestation rates analyzed by EKC studies. We limited the samples to countries classified as tropical by the UN Food and Agriculture Organization Forestry Department (ref. 19, data table 2) and paid special attention to differences between tropical countries in the UMI group and ones in lower income groups.The Malaysian case study allowed us to examine more closely the linkages from rising household income to increased household WTP, NGO engagement, and government protective action, and thereby uncover reasons for the underprovision of forest protection relative to household preferences. The case concerned Belum–Temengor, a 300,000-ha forested region in the state of Perak (Fig. 1). This region contains the largest area of primary forest in Peninsular Malaysia outside a national park. Our research included a population-representative survey of 1,261 rural and urban households in the Malaysian state of Selangor and the federal territory of Kuala Lumpur during 2010 (Materials and Methods). We used choice experiments (20, 21) to estimate household WTP to protect Belum–Temengor against logging and poaching (SI Text, section 2). Information from the case study enabled us to compare the public’s aggregate WTP for protection to current protection expenditures and to discuss why there is a gap between the two.Open in a separate windowFig. 1.Locations of Belum–Temengor (site of forest protection plans in choice experiments) and Selangor and Kuala Lumpur (site of household survey; the black dot is Kuala Lumpur) within Peninsular Malaysia (light gray). Lines show Malaysian state boundaries. Sources: base map, GADM database (www.gadm.org); Belum–Temengor boundaries, Forest Research Institute Malaysia.     

Low-dose sirolimus-eluting hydroxyapatite coating on stents does not increase platelet activation and adhesion ex vivo

We previously found paclitaxel-eluting polymer-coated stents causing more human platelet-monocyte complex formation than bare metal stents in vitro. Presently, we examined patterns of platelet activation and adhesion after exposure to 6 nanofilm HAp-coated (HAp-nano) stents, 6 HAp-microporous-coated (HAp-micro) stents, 5 HAp sirolimus-eluting microporous-coated (HAp-SES) stents and 5 cobalt-chromium stents (BMS) deployed in an in vitro flow system. Blood obtained from healthy volunteers was circulated and sampled at 0, 10, 30 and 60 min. By flow cytometry, there were no significant differences in P-Selectin expression between the 4 stent types (HAp-nano = 32.5%; HAp-micro = 42.5%, HAp-SES = 10.23%, BMS = 7% change from baseline at 60 min, p = NS); PAC-1 antibody binding (HAp-nano = 11.8%; HAp-micro = 2.9%, HAp-SES = 18%, BMS = 6.4% change from baseline at 60 min, p = NS) or PMC formation (HAp-nano = 21.6%; HAp-micro = 4%, HAp-SES = 6.6%, BMS = 17.4% change from baseline at 60 min, p = NS). The 4 stent types did not differ in the average number of platelet clusters >10 μm in diameter by SEM (HAp-nano = 2.39 ± 5.75; HAp-micro = 2.26 ± 3.43; HAp-SES = 1.93 ± 3.24; BMS = 1.94 ± 2.41, p = NS). The majority of the struts in each stent group were only mildly covered by platelets, (HAp-nano = 80%, HAp-micro = 61%, HAp-SES = 78% and BMS = 52.1%, p = NS). The HAp-microporous-coated stents (ECD) attracted slightly more proteinaceous material than bare metal stents (HAp-micro = 35% struts with complete protein coverage, P < 0.0001 vs. other 3 stent types). In conclusion, biomimetic stent coating with nanofilm or microporous hydroxyapatite, even when eluting low-dose sirolimus, does not increase the platelet activation in circulating human blood, or platelet adhesion to stent surface when compared to bare metal stents in vitro.     

CD44 enhances tumor formation and lung metastasis in experimental osteosarcoma and is an additional predictor for poor patient outcome

Formation of metastases in the lungs is the major cause of death in patients suffering from osteosarcoma (OS). Metastases at presentation and poor response to preoperative chemotherapy are strong predictors for poor patient outcome. The elucidation of molecular markers that promote metastasis formation and/or chemoresistance is therefore of importance. CD44 is a plasma membrane glycoprotein that binds to the extracellular matrix component hyaluronan (HA) and has been shown to be involved in metastasis formation in a variety of other tumors. Here we investigated the role of CD44 expression on OS tumor formation and metastasis. High CD44 expression, evaluated with a tissue microarray including samples from 53 OS patients and stained with a pan‐CD44 antibody (Hermes3), showed a tendency (p < 0.08) to shortened overall survival. However, nonresponders and patients with lung metastases and high CD44 expression had significantly poorer prognosis than patients with low CD44 expression. Overexpression of the standard CD44 isoform (CD44s) and its HA‐binding defective mutant R41A in osteoblastic SaOS‐2 cells resulted in HA‐independent higher migration rates and increased chemoresistance, partially dependent on HA. In an orthotopic mouse model of OS, overexpression of CD44s in SaOS‐2 cells resulted in an HA‐dependent increased primary tumor formation and increased numbers of micrometastases and macrometastases in the lungs. In conclusion, although CD44 failed to be an independent predictor for patient outcome in this limited cohort of OS patients, increased CD44 expression was associated with even worse survival in patients with chemoresistance and with lung metastases. CD44‐associated chemoresistance was also observed in vitro, and increased formation of lung metastases was found in vivo in SCID mice. © 2013 American Society for Bone and Mineral Research.     

A Short History of Parathyroid Hormone,Its Biological Role,and Pathophysiology of Hormone Excess

Research on parathyroid hormone (PTH) over the preceding century was an exciting but sometimes confusing tale, with steady advances yet long periods of stalled progress, angry debates, and missed opportunities. There were sometimes fierce debates about the function of the parathyroids. These were finally resolved by 1925 when a potent biologic extract useful for testing in animals was finally made by Collip, and the role of PTH in calcium metabolism was established unequivocally. In the decades that followed, the pathophysiology of hormone excess (severe bone loss and other symptoms) was elucidated. Diagnosis can now be made with high reliability, even in the absence of clinical manifestation. The modern clinical profile of asymptomatic hyperparathyroidism is best described as a disorder in which there are neither signs nor symptoms traditionally associated with hypercalcemia or PTH excess.     

An examination of associations between the inability to taste phenylthiocarbamide (PTC) and clinical characteristics and trait markers in first-episode,nonaffective psychotic disorders

Research findings are mixed as to whether or not the inability to taste phenylthiocarbamide (PTC) might represent an endophenotypic trait marker for schizophrenia. We hypothesized associations between PTC-tasting status and select clinical characteristics and trait markers in patients with psychotic disorders that, if present, would provide support for the inability to taste PTC as a trait marker. In a first-episode psychosis sample (n=93), we measured PTC tasting, family history of psychosis, age at onset of prodrome and psychosis, severity of positive and negative symptoms, global impairment in functioning, neurological soft signs, and four neurocognitive domains (verbal learning/memory, visual learning/memory, verbal working memory, and spatial working memory). Associations between PTC-non-tasting and clinical/neurocognitive variables were examined with χ² tests and independent samples t tests. Among participants, 67.7% tasted PTC in comparison to a strip of control paper, and 25.8% were non-tasters. Tasters and non-tasters did not show statistically significant differences with respect to family history, age at onset, severity of symptoms, neurological soft signs, or the four neurocognitive domains. In conjunction with other findings, it is unlikely that PTC-non-tasting is a trait marker of schizophrenia, though a conclusive study is warranted.     

Anti-stigma training and positive changes in mental illness stigma outcomes in medical students in ten countries: a mediation analysis on pathways via empathy development and anxiety reduction

Purpose

Studies of mental illness stigma reduction interventions have been criticised for failing to evaluate behavioural outcomes and mechanisms of action. This project evaluates training for medical students entitled ‘Responding to Experienced and Anticipated Discrimination’ (READ), developed to focus on skills in addition to attitudes and knowledge. We aimed to (i) evaluate the effectiveness of READ with respect to knowledge, attitudes, and clinical communication skills in responding to mental illness-related discrimination, and (ii) investigate whether its potential effectiveness was mediated via empathy or/and intergroup anxiety.

Methods

This is an international multisite non-randomised pre- vs post-controlled study. Eligible medical students were currently undertaking their rotational training in psychiatry. Thirteen sites across ten countries (n = 570) were included in the final analysis.

Results

READ was associated with positive changes in knowledge (mean difference 1.35; 95% CI 0.87 to 1.82), attitudes (mean difference − 2.50; 95% CI − 3.54 to − 1.46), skills (odds ratio 2.98; 95% CI 1.90 to 4.67), and simulated patient perceived empathy (mean difference 3.05; 95% CI 1.90 to 4.21). The associations of READ with knowledge, attitudes, and communication skills but not with simulated patient perceived empathy were partly mediated through student reported empathy and intergroup anxiety.

Conclusion

This is the first study to identify mediating effects of reduced intergroup anxiety and increased empathy in an evaluation of anti-stigma training that includes behavioural measures in the form of communication skills and perceived empathy. It shows the importance of both mediators for all of knowledge, skills, and attitudes, and hence of targeting both in future interventions.