Genome-wide analyses identify 21 infertility loci and over 400 reproductive hormone loci across the allele frequency spectrum

Genome-wide association studies (GWASs) may help inform treatments for infertility, whose causes remain unknown in many cases. Here we present GWAS meta-analyses across six cohorts for male and female infertility in up to 41,200 cases and 687,005 controls. We identified 21 genetic risk loci for infertility (P≤5E-08), of which 12 have not been reported for any reproductive condition. We found positive genetic correlations between endometriosis and all-cause female infertility (rg=0.585, P=8.98E-14), and between polycystic ovary syndrome and anovulatory infertility (rg=0.403, P=2.16E-03). The evolutionary persistence of female infertility-risk alleles in EBAG9 may be explained by recent directional selection. We additionally identified up to 269 genetic loci associated with follicle-stimulating hormone (FSH), luteinising hormone, oestradiol, and testosterone through sex-specific GWAS meta-analyses (N=6,095-246,862). While hormone-associated variants near FSHB and ARL14EP colocalised with signals for anovulatory infertility, we found no rg between female infertility and reproductive hormones (P>0.05). Exome sequencing analyses in the UK Biobank (N=197,340) revealed that women carrying testosterone-lowering rare variants in GPC2 were at higher risk of infertility (OR=2.63, P=1.25E-03). Taken together, our results suggest that while individual genes associated with hormone regulation may be relevant for fertility, there is limited genetic evidence for correlation between reproductive hormones and infertility at the population level. We provide the first comprehensive view of the genetic architecture of infertility across multiple diagnostic criteria in men and women, and characterise its relationship to other health conditions.

Exome-wide evidence of compound heterozygous effects across common phenotypes in the UK Biobank

Exome-sequencing association studies have successfully linked rare protein-coding variation to risk of thousands of diseases. However, the relationship between rare deleterious compound heterozygous (CH) variation and their phenotypic impact has not been fully investigated. Here, we leverage advances in statistical phasing to accurately phase rare variants (MAF ~ 0.001%) in exome sequencing data from 175,587 UK Biobank (UKBB) participants, which we then systematically annotate to identify putatively deleterious CH coding variation. We show that 6.5% of individuals carry such damaging variants in the CH state, with 90% of variants occurring at MAF < 0.34%. Using a logistic mixed model framework, systematically accounting for relatedness, polygenic risk, nearby common variants, and rare variant burden, we investigate recessive effects in common complex diseases. We find six exome-wide significant (P < 1.68 × 10 - 7 ) and 17 nominally significant (P < 5.25 × 10 - 5 ) gene-trait associations. Among these, only four would have been identified without accounting for CH variation in the gene. We further incorporate age-at-diagnosis information from primary care electronic health records, to show that genetic phase influences lifetime risk of disease across 20 gene-trait combinations (FDR < 5%). Using a permutation approach, we find evidence for genetic phase contributing to disease susceptibility for a collection of gene-trait pairs, including FLG-asthma (P = 0.00205 ) and USH2A-visual impairment (P = 0.0084 ). Taken together, we demonstrate the utility of phasing large-scale genetic sequencing cohorts for robust identification of the phenome-wide consequences of compound heterozygosity.

Analysis of genetic dominance in the UK Biobank

Classical statistical genetics theory defines dominance as any deviation from a purely additive, or dosage, effect of a genotype on a trait, which is known as the dominance deviation. Dominance is well documented in plant and animal breeding. Outside of rare monogenic traits, however, evidence in humans is limited. We systematically examined common genetic variation across 1060 traits in a large population cohort (UK Biobank, N = 361,194 samples analyzed) for evidence of dominance effects. We then developed a computationally efficient method to rapidly assess the aggregate contribution of dominance deviations to heritability. Lastly, observing that dominance associations are inherently less correlated between sites at a genomic locus than their additive counterparts, we explored whether they may be leveraged to identify causal variants more confidently.

The genetic architecture of changes in adiposity during adulthood

Obesity is a heritable disease, characterised by excess adiposity that is measured by body mass index (BMI). While over 1,000 genetic loci are associated with BMI, less is known about the genetic contribution to adiposity trajectories over adulthood. We derive adiposity-change phenotypes from 1.5 million primary-care health records in over 177,000 individuals in UK Biobank to study the genetic architecture of weight-change. Using multiple BMI measurements over time increases power to identify genetic factors affecting baseline BMI. In the largest reported genome-wide study of adiposity-change in adulthood, we identify novel associations with BMI-change at six independent loci, including rs429358 (a missense variant in APOE). The SNP-based heritability of BMI-change (1.98%) is 9-fold lower than that of BMI, and higher in women than in men. The modest genetic correlation between BMI-change and BMI (45.2%) indicates that genetic studies of longitudinal trajectories could uncover novel biology driving quantitative trait values in adulthood.

Systematic single-variant and gene-based association testing of thousands of phenotypes in 394,841 UK Biobank exomes

Genome-wide association studies have successfully discovered thousands of common variants associated with human diseases and traits, but the landscape of rare variations in human disease has not been explored at scale. Exome-sequencing studies of population biobanks provide an opportunity to systematically evaluate the impact of rare coding variations across a wide range of phenotypes to discover genes and allelic series relevant to human health and disease. Here, we present results from systematic association analyses of 4,529 phenotypes using single-variant and gene tests of 394,841 individuals in the UK Biobank with exome-sequence data. We find that the discovery of genetic associations is tightly linked to frequency and is correlated with metrics of deleteriousness and natural selection. We highlight biological findings elucidated by these data and release the dataset as a public resource alongside the Genebass browser for rapidly exploring rare-variant association results.

The female protective effect against autism spectrum disorder

Autism spectrum disorder (ASD) is diagnosed three to four times more frequently in males than in females. Genetic studies of rare variants support a female protective effect (FPE) against ASD. However, sex differences in common inherited genetic risk for ASD are less studied, particularly within families. Leveraging the Danish iPSYCH resource, we found siblings of female ASD cases (n = 1,707) had higher rates of ASD than siblings of male ASD cases (n = 6,270; p < 1.0 × 10-10). In the Simons Simplex and SPARK collections, mothers of ASD cases (n = 7,436) carried more polygenic risk for ASD than fathers of ASD cases (n = 5,926; 0.08 polygenic risk score [PRS] SD; p = 7.0 × 10-7). Further, male unaffected siblings under-inherited polygenic risk (n = 1,519; p = 0.03). Using both epidemiologic and genetic approaches, our findings strongly support an FPE against ASD's common inherited influences.

Rare coding variants in ten genes confer substantial risk for schizophrenia

Rare coding variation has historically provided the most direct connections between gene function and disease pathogenesis. By meta-analysing the whole exomes of 24,248 schizophrenia cases and 97,322 controls, we implicate ultra-rare coding variants (URVs) in 10 genes as conferring substantial risk for schizophrenia (odds ratios of 3-50, P < 2.14 × 10-6) and 32 genes at a false discovery rate of <5%. These genes have the greatest expression in central nervous system neurons and have diverse molecular functions that include the formation, structure and function of the synapse. The associations of the NMDA (N-methyl-D-aspartate) receptor subunit GRIN2A and AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid) receptor subunit GRIA3 provide support for dysfunction of the glutamatergic system as a mechanistic hypothesis in the pathogenesis of schizophrenia. We observe an overlap of rare variant risk among schizophrenia, autism spectrum disorders1, epilepsy and severe neurodevelopmental disorders2, although different mutation types are implicated in some shared genes. Most genes described here, however, are not implicated in neurodevelopment. We demonstrate that genes prioritized from common variant analyses of schizophrenia are enriched in rare variant risk3, suggesting that common and rare genetic risk factors converge at least partially on the same underlying pathogenic biological processes. Even after excluding significantly associated genes, schizophrenia cases still carry a substantial excess of URVs, which indicates that more risk genes await discovery using this approach.

A data harmonization pipeline to leverage external controls and boost power in GWAS

The use of external controls in genome-wide association study (GWAS) can significantly increase the size and diversity of the control sample, enabling high-resolution ancestry matching and enhancing the power to detect association signals. However, the aggregation of controls from multiple sources is challenging due to batch effects, difficulty in identifying genotyping errors, and the use of different genotyping platforms. These obstacles have impeded the use of external controls in GWAS and can lead to spurious results if not carefully addressed. We propose a unified data harmonization pipeline that includes an iterative approach to quality control (QC) and imputation, implemented before and after merging cohorts and arrays. We apply this harmonization pipeline to aggregate 27 517 European control samples from 16 collections within dbGaP. We leverage these harmonized controls to conduct a GWAS of Crohn's disease. We demonstrate a boost in power over using the cohort samples alone, and that our procedure results in summary statistics free of any significant batch effects. This harmonization pipeline for aggregating genotype data from multiple sources can also serve other applications where individual level genotypes, rather than summary statistics, are required.

The impact of non-additive genetic associations on age-related complex diseases

Genome-wide association studies (GWAS) are not fully comprehensive, as current strategies typically test only the additive model, exclude the X chromosome, and use only one reference panel for genotype imputation. We implement an extensive GWAS strategy, GUIDANCE, which improves genotype imputation by using multiple reference panels and includes the analysis of the X chromosome and non-additive models to test for association. We apply this methodology to 62,281 subjects across 22 age-related diseases and identify 94 genome-wide associated loci, including 26 previously unreported. Moreover, we observe that 27.7% of the 94 loci are missed if we use standard imputation strategies with a single reference panel, such as HRC, and only test the additive model. Among the new findings, we identify three novel low-frequency recessive variants with odds ratios larger than 4, which need at least a three-fold larger sample size to be detected under the additive model. This study highlights the benefits of applying innovative strategies to better uncover the genetic architecture of complex diseases.

Predicting functional effects of missense variants in voltage-gated sodium and calcium channels

Malfunctions of voltage-gated sodium and calcium channels (encoded by SCNxA and CACNA1x family genes, respectively) have been associated with severe neurologic, psychiatric, cardiac, and other diseases. Altered channel activity is frequently grouped into gain or loss of ion channel function (GOF or LOF, respectively) that often corresponds not only to clinical disease manifestations but also to differences in drug response. Experimental studies of channel function are therefore important, but laborious and usually focus only on a few variants at a time. On the basis of known gene-disease mechanisms of 19 different diseases, we inferred LOF (n = 518) and GOF (n = 309) likely pathogenic variants from the disease phenotypes of variant carriers. By training a machine learning model on sequence- and structure-based features, we predicted LOF or GOF effects [area under the receiver operating characteristics curve (ROC) = 0.85] of likely pathogenic missense variants. Our LOF versus GOF prediction corresponded to molecular LOF versus GOF effects for 87 functionally tested variants in SCN1/2/8A and CACNA1I (ROC = 0.73) and was validated in exome-wide data from 21,703 cases and 128,957 controls. We showed respective regional clustering of inferred LOF and GOF nucleotide variants across the alignment of the entire gene family, suggesting shared pathomechanisms in the SCNxA/CACNA1x family genes.

Autism spectrum disorder and attention deficit hyperactivity disorder have a similar burden of rare protein-truncating variants

We analyze the exome sequences of approximately 8,000 children with autism spectrum disorder (ASD) and/or attention-deficit/hyperactivity disorder (ADHD) and 5,000 controls, and we find that ASD and ADHD have a similar burden of rare protein-truncating variants in evolutionarily constrained genes, both significantly higher than controls. This motivates a combined analysis across ASD and ADHD, which identifies microtubule-associated protein 1A (MAP1A) as a novel exome-wide significant gene conferring risk for childhood psychiatric disorders.

Mapping the drivers of within-host pathogen evolution using massive data sets

Differences among hosts, resulting from genetic variation in the immune system or heterogeneity in drug treatment, can impact within-host pathogen evolution. Genetic association studies can potentially identify such interactions. However, extensive and correlated genetic population structure in hosts and pathogens presents a substantial risk of confounding analyses. Moreover, the multiple testing burden of interaction scanning can potentially limit power. We present a Bayesian approach for detecting host influences on pathogen evolution that exploits vast existing data sets of pathogen diversity to improve power and control for stratification. The approach models key processes, including recombination and selection, and identifies regions of the pathogen genome affected by host factors. Our simulations and empirical analysis of drug-induced selection on the HIV-1 genome show that the method recovers known associations and has superior precision-recall characteristics compared to other approaches. We build a high-resolution map of HLA-induced selection in the HIV-1 genome, identifying novel epitope-allele combinations.

Identification of common genetic risk variants for autism spectrum disorder

Autism spectrum disorder (ASD) is a highly heritable and heterogeneous group of neurodevelopmental phenotypes diagnosed in more than 1% of children. Common genetic variants contribute substantially to ASD susceptibility, but to date no individual variants have been robustly associated with ASD. With a marked sample-size increase from a unique Danish population resource, we report a genome-wide association meta-analysis of 18,381 individuals with ASD and 27,969 controls that identified five genome-wide-significant loci. Leveraging GWAS results from three phenotypes with significantly overlapping genetic architectures (schizophrenia, major depression, and educational attainment), we identified seven additional loci shared with other traits at equally strict significance levels. Dissecting the polygenic architecture, we found both quantitative and qualitative polygenic heterogeneity across ASD subtypes. These results highlight biological insights, particularly relating to neuronal function and corticogenesis, and establish that GWAS performed at scale will be much more productive in the near term in ASD.

Discovery of the first genome-wide significant risk loci for attention deficit/hyperactivity disorder

Attention deficit/hyperactivity disorder (ADHD) is a highly heritable childhood behavioral disorder affecting 5% of children and 2.5% of adults. Common genetic variants contribute substantially to ADHD susceptibility, but no variants have been robustly associated with ADHD. We report a genome-wide association meta-analysis of 20,183 individuals diagnosed with ADHD and 35,191 controls that identifies variants surpassing genome-wide significance in 12 independent loci, finding important new information about the underlying biology of ADHD. Associations are enriched in evolutionarily constrained genomic regions and loss-of-function intolerant genes and around brain-expressed regulatory marks. Analyses of three replication studies: a cohort of individuals diagnosed with ADHD, a self-reported ADHD sample and a meta-analysis of quantitative measures of ADHD symptoms in the population, support these findings while highlighting study-specific differences on genetic overlap with educational attainment. Strong concordance with GWAS of quantitative population measures of ADHD symptoms supports that clinical diagnosis of ADHD is an extreme expression of continuous heritable traits.

Discovery of the first genome-wide significant risk loci for attention deficit/hyperactivity disorder

Attention deficit/hyperactivity disorder (ADHD) is a highly heritable childhood behavioral disorder affecting 5% of children and 2.5% of adults. Common genetic variants contribute substantially to ADHD susceptibility, but no variants have been robustly associated with ADHD. We report a genome-wide association meta-analysis of 20,183 individuals diagnosed with ADHD and 35,191 controls that identifies variants surpassing genome-wide significance in 12 independent loci, finding important new information about the underlying biology of ADHD. Associations are enriched in evolutionarily constrained genomic regions and loss-of-function intolerant genes and around brain-expressed regulatory marks. Analyses of three replication studies: a cohort of individuals diagnosed with ADHD, a self-reported ADHD sample and a meta-analysis of quantitative measures of ADHD symptoms in the population, support these findings while highlighting study-specific differences on genetic overlap with educational attainment. Strong concordance with GWAS of quantitative population measures of ADHD symptoms supports that clinical diagnosis of ADHD is an extreme expression of continuous heritable traits.

A naturally protective epitope of limited variability as an influenza vaccine target

Current antigenic targets for influenza vaccine development are either highly immunogenic epitopes of high variability or conserved epitopes of low immunogenicity. This requires continuous update of the variable epitopes in the vaccine formulation or boosting of immunity to invariant epitopes of low natural efficacy. Here we identify a highly immunogenic epitope of limited variability in the head domain of the H1 haemagglutinin protein. We show that a cohort of young children exhibit natural immunity to a set of historical influenza strains which they could not have previously encountered and that this is partially mediated through the epitope. Furthermore, vaccinating mice with these epitope conformations can induce immunity to human H1N1 influenza strains that have circulated since 1918. The identification of epitopes of limited variability offers a mechanism by which a universal influenza vaccine can be created; these vaccines would also have the potential to protect against newly emerging influenza strains.

Adenosine Nucleotides and Serotonin Stimulate von Wille-brand Factor Release from Cultured Human Endothelial Cells

Endothelial cells (ECs) synthesize and release von Willebrand factor (vWf) either constitutively or from Weibel-Palade bodies by a regulated pathway. Although stimulated release of vWf from ECs occurs following exposure to thrombin, histamine, interleukin, tissue necrosis factor and fibrin in vitro, these agents are unlikely to be present in physiologically relevant concentrations during the initial stages of primary hemostasis. Alternatively, agents known to be released from the dense granules of activated platelets at the sites of vascular injury may provide the initial physiological stimuli for vWf release from ECs in vivo. We have examined the effects of the platelet secretagogues ADP, AMP, ATP and serotonin on the release of vWf from ECs and demonstrated enhanced release in all cases. The extent and time at which optimum vWf release was observed depended on the agonist and its concentration. At 3 nM, optimum release occurred after 4 hours with ADP (330 %/ml) or 1 h with AMP (153%/ml) or ATP (450%/ml). At 30 nM, optimum release was seen after 1 hour with ADP (315 %/ml) or AMP (595%/ml) and after 15 min with ATP (938%/ml). With serotonin, optimal release was seen by 30 min at 0.3 μM (1034%/ml) and after 1 h at 1 pM (745%/ml) although the response after 15 min was nearly equivalent (667%/ml). The doses giving 50% of maximal response (ED50) after 1 h were 6.5 nM (ADP), 15.2 nM (AMP) and 2.4 nM (ATP) and 20 nM for ATP or 75 nM for serotonin after 15 or 30 min respectively. ADP also enhanced PGI2 release from ECs in a dose- and time-dependent manner. These observations support a mechanism whereby activated platelets, which interact with and bind to ECs or subendothelium and release adenine nucleotides or serotonin from platelet dense granules, could stimulate the release of vWf from adjacent ECs thereby enhancing EC-platelet interactions and facilitating primary hemostasis.

Disparity Between One- and Two-Stage Factor VIII Assays in Measuring VIIIC in Heparinized Plasma

The level of Factor VIII procoagulant activity (VIIIC) was found to be more than 30% higher in heparinized plasma than in citrated plasma from the same donor when determined by a one-stage assay (1.34 U/ml versus 1.0 U/ml). However, after Al(OH)3 adsorption and two-stage assay, the VIIIC levels were not significantly different for the two types of plasma (0.90 ± 0.25 U/ ml versus 0.82 ± 0.23 U/ml). If a one-stage assay was employed after adsorption, a similar low result was obtained (0.92 ± 0.21 U/ ml versus 0.91 ± 0.12 U/ml). This indicated that the adsorption step itself was responsible for the difference in results. Parallel analyses of other VIII markers demonstrated that more VIIIC antigen (VIIICAg) was removed by adsorption of heparinized rather than citrated plasma (0.33 U/ml versus 0.12 U/ml) although there was no difference in the level of VUI-related antigen (VIIIRAg). The results show that adsorption of heparinized plasma prior to either one- or two-stage assay leads to a greater loss of both VIIIC and VIIICAg activity than observed with citrated plasma and indicate that, when applied to heparin plasma the two-stage assay for VIIIC underestimates the actual VIIIC content.

A novel, automated method of temperature cycling to produce cryoprecipitate

BACKGROUND

Cryoprecipitate continues to find wide application in transfusion practice. Current AABB standards call for a minimum of 80 units (U) of factor VIII and 150 mg of fibrinogen per bag of cryoprecipitate. However, individual cryoprecipitates can vary greatly in content, with as many as 20 different factors known to affect the yield.

STUDY DESIGN AND METHODS

Plasma was processed in a new, rapid, automated device (CryoSeal, Thermogenesis) with computer-controlled temperature cycling to produce cryoprecipitate.

RESULTS

In repeat runs (n = 20), the automated procedure yielded a product containing 184 mg of fibrinogen and 158 U of factor VIII in 55 minutes. Additional studies using plasma pools to compare the quality of the machine-generated products to those of traditionally prepared cryoprecipitate showed comparative recoveries of 182 and 187 mg of fibrinogen and 172.1 and 129.7 U of factor VIII and no significant difference in the levels of plasminogen, protein C, or protein S.

CONCLUSION

The new system offers an automated method of cryoprecipitate production in which the steps involved in temperature cycling are initiated sequentially, producing within 1 hour a preparation that is equivalent to standard cryoprecipitate.

Prevention of cytokine accumulation in platelets obtained with the COBE spectra apheresis system

BACKGROUND AND OBJECTIVES

Febrile nonhemolytic transfusion reactions frequently accompany platelet transfusions and may be due to accumulation of cytokines mediating inflammation during storage of platelet concentrates (PCs). We wished to determine whether PCs collected using the COBE(R) SpectraTM Apheresis System (Version 4) were sufficiently leukocyte reduced (LR) to limit cytokine accumulation during storage.

MATERIALS AND METHODS

Cytokine accumulation - interleukin (IL)-1beta, IL-6, IL-8, tumor necrosis factor-alpha (TNF-alpha) - and release of platelet alpha-granule - P-selectin, transforming growth factor-beta1 (TGF-beta1), platelet-derived growth factor AB (PDGF-AB), von Willebrand factor (vWf) - or dense granule (serotonin) markers were investigated during a 7-day storage period comparing apheresis-collected, LR PCs (LR PCs) and random donor platelets prepared from whole blood (WB).

RESULTS

Leukocyte counts were reduced 99.95% comparing LR PCs (5.7 x 10(5)/l) and WB PCs (1.09 x 10(9)/l). Little or no accumulation of leukocyte-derived cytokines was observed in LR PCs during storage in contrast to WB PCs. A reduction in the release of platelet alpha-granule proteins, such as P-selectin, TGF-beta1 and PDGF-AB, was observed on day 0 for LR PCs compared to WB PCs with little or no difference observed from day 3 to 7. Plasma vWf levels were higher in LR PCs compared to WB PCs on days 0-7.

CONCLUSION

Leukocyte levels in PCs collected with the COBE Spectra Apheresis System are sufficiently low to limit cytokine production during 7 days of storage.

Influences on parent perceptions of inclusive practices for their children with mental retardation

Influences on parent perceptions regarding the practice of integrating students with significant cognitive disabilities into general education classrooms were examined. Findings confirmed that perceptions were significantly influenced by characteristics of the parent and the child as well as by factors associated with the child's placement history. Further, factors influencing these perceptions differed according to varying dimensions of inclusion being considered. We argue that the efficacy of any specific type of educational model cannot be determined without a consideration of the complex dynamics involved in the interplay between individual child characteristics, parent and family values, and the perceived role of the school.

Identification of novel factor VIII inhibitor epitopes using synthetic peptide arrays

OBJECTIVES

Mapping the antibody-binding sites on the factor VIII (FVIII) protein opens the prospect of studying the development of FVIII inhibitors and the alteration of inhibitor specificities over time. This paper describes a novel approach to the mapping of FVIII antibody-binding sites.

METHODS

Immobilized synthetic peptide arrays covering 80% of the complete 2351 amino acid sequence of factor VIII (FVIII) were used to determine epitope specificity of 6 alloantibodies and 3 autoantibodies inhibitory to FVIII activity. This detailed assessment was carried out using a modified enzyme-linked immunosorbent assay with plasma from normal persons or hemophilia A patients without inhibitors as negative controls.

RESULTS

Antibody-combining sites could be differentiated in both a qualitative and quantitative manner and were patient-specific. Highly reactive peptides were restricted to specific sites in the A1-A3 and C1-C2 domains and were not proximal to known proteolytic cleavage sites. Free peptides incubated in vitro with the plasmas of 3 patients significantly reduced residual inhibitor titers in a dose-dependent manner.

CONCLUSION

This technique permits the study of the development and specificity of FVIII inhibitors, can detect and differentiate between inhibitory and noninhibitory antibodies using immobilized or free peptides respectively, permits correlation of antibody-combining sites with inhibition of FVIII activity and provides a basis for the development of inhibitor adsorption or neutralization technology.

Effect of filtration of platelet concentrates on the accumulation of cytokines and platelet release factors during storage

BACKGROUND

Platelet transfusions are frequently accompanied by febrile nonhemolytic transfusion reactions. These may be due, in part, to the release of cytokines interleukin 1 beta (IL-1 beta), interleukin 6 (IL-6), interleukin 8 (IL-8), and tumor necrosis factor alpha (TNF-alpha) by white cells (WBCs) into the plasma during storage of platelet concentrates (PCs). Acting as endogenous pyrogens, these agents may induce inflammatory responses.

STUDY DESIGN AND METHODS

This study proposed to determine if WBC reduction in PCs by filtration significantly reduced the levels of cytokines normally generated during storage of unfiltered PCs up to 5 days. Serotonin, platelet-derived growth factor (PDGF-AB), and von Willebrand factor levels were also assessed to establish whether or not filtration or storage elicited significant platelet activation and granule release.

RESULTS

Filtration significantly reduced total WBC counts by 99.1 percent before storage (p < 0.001) without affecting total platelet counts. Compared to unfiltered PCs, filtration prevented a rise in the levels of each cytokine by Day 3 for IL-1 beta (27.7 vs. 0.6 pg/mL; p < 0.05), IL-6 (114.2 vs. 0.4 pg/mL; p < 0.001), and IL-8 (4.2 vs. 0.02 ng/mL; p < 0.001). By Day 5, further increases in the levels of all cytokines were noted in unfiltered PCs, but Day 0 levels remained in filtered PCs (IL-1 beta: 105.4 vs. 0.4 pg/mL, p < 0.001; TNF-alpha: 42.2 vs. 7.5 pg/mL, p < 0.025; IL-6: 268.8 vs. 0.4 pg/mL, p < 0.001; and IL-8: 7.6 vs. 0.02 ng/mL, p < 0.001). From Day 0 to Day 5, there were significant increases in serotonin (21.3 vs. 6.3 ng/mL, p < 0.05), PDGF-AB (72.6 vs. 25.8 ng/mL, p < 0.001), and von Willebrand factor (4.7 vs. 2.7 IU/mL, p < 0.05) in unfiltered PCs, with similar increased levels being observed in filtered PCs during storage.

CONCLUSION

These data indicate that the accumulation of high levels of cytokines in stored PCs could be prevented by WBC-reduction filtration of PCs without the induction of significant platelet activation or granule release. As cytokines have the potential to induce febrile nonhemolytic transfusion reactions in patients, the transfusion of WBC-reduced PCs would be expected to reduce the frequency and severity of such reactions.

Adenosine nucleotides and serotonin stimulate von Willebrand factor release from cultured human endothelial cells

Endothelial cells (ECs) synthesize and release von Willebrand factor (vWf) either constitutively or from Weibel-Palade bodies by a regulated pathway. Although stimulated release of vWf from ECs occurs following exposure to thrombin, histamine, interleukin, tissue necrosis factor and fibrin in vitro, these agents are unlikely to be present in physiologically relevant concentrations during the initial stages of primary hemostasis. Alternatively, agents known to be released from the dense granules of activated platelets at the sites of vascular injury may provide the initial physiological stimuli for vWf release from ECs in vivo. We have examined the effects of the platelet secretagogues ADP, AMP, ATP and serotonin on the release of vWf from ECs and demonstrated enhanced release in all cases. The extent and time at which optimum vWf release was observed depended on the agonist and its concentration. At 3 nM, optimum release occurred after 4 hours with ADP (330%/ml) or 1 h with AMP (153%/ml) or ATP (450%/ml). At 30 nM, optimum release was seen after 1 hour with ADP (315%/ml) or AMP (595%/ml) and after 15 min with ATP (938%/ml). With serotonin, optimal release was seen by 30 min at 0.3 microM (1034%/ml) and after 1 h at 1 microM (745%/ml) although the response after 15 min was nearly equivalent (667%/ml). The doses giving 50% of maximal response (ED50) after 1 h were 6.5 nM (ADP), 15.2 nM (AMP) and 2.4 nM (ATP) and 20 nM for ATP or 75 nM for serotonin after 15 or 30 min respectively. ADP also enhanced PGI2 release from ECs in a dose- and time-dependent manner.(ABSTRACT TRUNCATED AT 250 WORDS)

Computer-generated slide technology

Presentation technology is available, and it does not have to be expensive. This article describes computer hardware and software concepts for graphics use, and recommends principles for making cost-effective buying decisions. Also included is a previously published technique for making custom computer graphic 35-mm slides at minimal expense. This information is vital to anyone lecturing without the support of a custom graphics laboratory.

Characterization of factors affecting the stability of frozen heparinized plasma

The use of heparin rather than citrate as primary anticoagulant has been shown to significantly improve the initial activity, stability and recovery of factor VIII:C from human plasma, cryoprecipitates or factor VIII concentrates if the plasma was initially frozen at -80 degrees C and subsequently stored at this temperature. If frozen and stored at progressively warmer temperatures however, increasing amounts of insoluble protein aggregates, termed storage precipitates (SPs), were recovered in the thawed plasma and cryoprecipitate fractions. Plasma recovery by centrifugation at 7,000 g for 7 min [Method I (MI)], 2 x 10 min (MII) or 15 min (MIII) had little effect on SP formation after 1 month at any storage temperature. After 4 months at -20 degrees C, more SP was recovered from MIII plasma whereas at -40 degrees C, more SP was recovered from MI plasma. Also, the preparation method had little or no effect on factor VIII:C activity at equivalent storage times or temperatures. A trend towards improved factor VIII recoveries was noted at lower freezing and storage temperatures however. SP formation was associated with reduced fibrinogen levels in the recovered plasma without loss of antithrombin-III or increased fibrinopeptide-A. Western blots showed polymerization of A alpha or gamma-chains of fibrinogen. SP formation was reduced or eliminated with factor XIII inhibitors, antibody to the active factor XIII a subunit or adjustment of heparinized plasma to 5-10 mM sodium citrate before initial freezing and storage. Although plasma factor VIII:C recoveries were only slightly affected at these citrate concentrations under most conditions, its recovery in cryoprecipitates was substantially improved owing to the reduction or absence of SPs.

Platelet-activating factor secreted by DDAVP-treated monocytes mediates von Willebrand factor release from endothelial cells

We have previously shown that although DDAVP (1-deamino-8-D-arginine vasopressin), a synthetic analogue of the natural hormone arginine vasopressin, does not directly promote release of vWf from human umbilical vein endothelial cells (ECs), enhanced release does occur when ECs were exposed to either monocytes or to supernatants recovered from DDAVP-treated monocytes. In the present study, we have found that exposure of monocytes to DDAVP did not increase secretion of interleukins (IL)-1 beta, IL-6, IL-8, tumor necrosis factor (TNF-alpha), growth factors G-CSF (granulocyte-), GM-CSF (granulocyte, monocyte-colony stimulating factor), prostaglandins (PG) E2, PGF2 alpha, or PGI2 or purine nucleotides such as ATP and ADP. However, increased levels of platelet-activating factor (PAF) were secreted by DDAVP-treated monocytes in a time- and dose-dependent manner that positively correlated with the enhancement in vWf release from ECs. Moreover, this effect could also be elicited when lipid extracts of these supernatants or purified PAF were added directly to ECs. This response could be inhibited with (+/-)-trans-2,5-Bis(3,4,5-trimethoxyphenyl)-1,3-dioxolane, a specific PAF receptor antagonist, when the ECs were exposed to supernatants from DDAVP-treated monocytes or to pure PAF. The present data indicate that enhanced secretion of PAF from monocytes is one mechanism whereby DDAVP can provoke release of vWf from ECs.

Temperature extremes produced orally by hot and cold liquids

Thermocycling in vitro is a common way of testing dental materials to aid in establishing suitability for in vivo use. There is no standard temperature range for dental material thermocycling. This research attempts to establish an appropriate temperature range by measuring extremes of temperature achieved orally in human volunteer subjects. By using an intraoral digital thermometer probe, 13 human subjects were observed as they drank very hot and cold liquids. The temperature extremes produced intraorally were measured and adjusted for possible error. The results of this study suggest that a range of 0 degrees to 67 degrees C may be appropriate for dental material thermocycling.

Definition of the affinity of binding between human von Willebrand factor and coagulation factor VIII

Factor VIII and von Willebrand factor are two plasma proteins essential for effective hemostasis. In vivo, they form a non-covalent complex whose association appears to be metal ion dependent. However, a precise definition of the nature of the molecular forces governing their association remains to be defined, as does their binding affinity. In this paper we have determined the dissociation constant and stoichiometry for Factor VIII binding to immobilized von Willebrand factor. The data demonstrate that these proteins interact saturably and with relatively high affinity. Computer assisted analyses of the Scatchard data favour a two site binding model. The higher affinity site was found to have a Kd of 62 (+/- 13) x 10(-12) M while that of the lower affinity site was 380 (+/- 92) x 10(-12) M. The density of Factor VIII binding sites (Bmax) present on von Willebrand factor was 31 (+/- 3) pM for the high affinity binding site and 46 (+/- 6) pM for the lower site, corresponding to a calculated Factor VIII: von Willebrand factor binding ratio of 1:33 and 1:23, respectively.

Wear of human enamel against a commercial castable ceramic restorative material

This study determined the effect of castable ceramic, with and without shading porcelain applied, on enamel wear. The wear produced by conventional dental porcelain was used as a control. Cusp tips from extracted human third molars were precision-machined into cones of enamel approximately 1 mm long. Three groups of nine cones each were abraded against rotating disks of (1) castable ceramic with shading porcelain, (2) castable ceramic without shading porcelain, and (3) conventional dental porcelain. Enamel wear was calculated from microscopic measurements of the enamel cones before and after abrading. Mean and standard deviation values were 1.220 +/- 0.218 for castable ceramic with shading porcelain, 0.639 +/- 0.218 for castable ceramic without shading porcelain, and 0.785 +/- 0.311 for glazed conventional dental porcelain (all values are X 10(-3) cm3). Significant differences were found between castable ceramic with and without shading porcelain and between conventional dental porcelain and castable ceramic with shading porcelain (p less than 0.001 ANOVA and 0.05 Scheffe's test). These findings suggest that castable ceramic with shading porcelain should not be used in regions that will function against opposing natural teeth.

Development of a heat-treated factor VIII/von Willebrand factor concentrate prepared from heparinized plasma

A high yield, intermediate purity factor VIII concentrate derived from heparinized plasma has been developed which can be heat-treated at 60 degrees C, 68 degrees C or 80 degrees C/72 h to permit inactivation of viral contaminants which may be present. After cold reprecipitation of the heparinized cryoprecipitate (CRC), the resolubilized CRC precipitate was adjusted to 25-30 mg/ml protein and pH 6.35 +/- 0.1 and incubated for 1 h at 8 degrees C. After centrifugation to remove the precipitated fibrinogen and fibronectin, a factor VIII-rich supernatant can be recovered which contains greater than 500 units of VIII:C per liter of starting plasma (Method I product) at a purity of 1.5 U/mg protein. Adjusted to 50 mM glycine and pH 6.8, the product can be lyophilized and heat-treated at 60 degrees C/72 h without a significant loss of VIII:C activity. However, at 68 degrees C or 80 degrees C/72 h, temperatures now reported to be more effective in viral inactivation, the recoveries were reduced to 68 and 33% respectively. Significantly improved recoveries after heat-treatment (HT) at 68 degrees C or 80 degrees C/72 h were achieved if the 8 degrees C supernatant product was prepared by a modified procedure (Method II). This further reduces the fibrinogen content of the product while maintaining VIII:C yields greater than 500 U/l at a purity of 1.9 U/mg. When adjusted to 50 mM glycine and 1-2% (w/v) sucrose (pH 6.8), lyophilized and heat treated at 60 degrees C, 68 degrees C or 80 degrees C/72 h, the VIII:C recoveries of Method II product were 88-100%, 79-84% and 80-83% of pre-HT levels respectively. The yield of VIII:C was greater than 400 U/l at a purity of 1.6-1.4 U/mg at 1-2% (w/v) sucrose even after the severe heat-treatment at 80 degrees C. In addition, the von Willebrand factor multimers are similar in size and triplet pattern to those observed in routine cryoprecipitate preparations.

DDAVP-induced release of von Willebrand factor from endothelial cells in vitro: the effect of plasma and blood cells

The vasopressin analogue 1-deamino-8-D-arginine vasopressin (DDAVP) causes an immediate, transient rise in plasma levels of von Willebrand factor (vWF) after its administration. Although it is recognized that vascular endothelial cells play an essential role in this process, the molecular basis of the response is not understood. We have investigated the phenomenon using human umbilical vein endothelial cells as an in vitro model. When normal individuals were stimulated with DDAVP, plasma from blood samples collected subsequently caused the release of vWF from cultured endothelial cells over a 24 h period (22-46% increase over baseline), compared to control plasma (5-17%). DDAVP added directly to the endothelial cells produced no increase in vWF release. When whole blood was treated in vitro with DDAVP, and the plasma subsequently added to endothelial cells, a significant increase in vWF secretion was found. Peripheral blood mononuclear cells were then tested. In the presence of DDAVP, an increased response occurred. Further fractionation of these cells showed that monocytes were largely responsible, causing an increased vWF release of 162% at 2 h. These observations were reinforced by finding that the supernatants of monocytes incubated with DDAVP were also effective in causing increased vWF release (118% compared to 58% for the control sample). Our studies suggest that DDAVP plays an indirect role in causing the release of vWF from endothelial cells, and that peripheral blood monocytes may act as intermediary target cells, which then produce factor(s) acting directly on endothelial cells.

Comparative study of the efficacy and safety of intranasal DDAVP administered to normal blood donors

A study of the efficacy and safety of intranasal 1-deamino-8-D-arginine vasopressin (DDAVP; 300 micrograms) in normal blood donors was carried out in a double-blind, controlled, comparative study. In addition, the effect of heparin or citrate anticoagulation of blood on the recovery of factor VIII (FVIII) in plasma, cryoprecipitate, and a FVIII concentrate was assessed. Citrated plasma from placebo (CP) or DDAVP-treated donors (CD) contained 1103 +/- 73 and 1470 +/- 141 units per liter of FVIII, respectively (p less than 0.01), whereas the heparinized plasma from placebo (HP) or DDAVP-treated donors (HD) contained 1328 +/- 130 (p less than 0.01) and 2023 +/- 358 units per liter (p less than 0.01), respectively. The FVIII could be recovered in both cryoprecipitate and cold-reprecipitated cryoprecipitate (CRC) fractions. DDAVP treatment improved FVIII recovery by 41 percent in the concentrate from citrated plasma (p less than 0.01) and by 127 percent in that from heparinized plasma (p less than 0.01). The specific activity of concentrates from the CP, CD, HP, and HD groups was 0.95 +/- 0.1, 1.4 +/- 0.1 (p less than 0.01), 0.9 +/- 0.1, and 1.47 +/- 0.2 U per mg of protein (p less than 0.01), respectively. The stability of the final product was the same, regardless of the method of treatment or collection. The side effects of intranasal treatment were mild and transient and occurred with similar frequency in both placebo and DDAVP treatment groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Human factor VIII from heparinized plasma. Purification and characterization of a single-chain form

Human factor VIII was purified from heparinized blood by cryoprecipitation, poly(ethyleneglycol) precipitation, Affi-Gel blue, aminohexyl, polyelectrolyte E5 and immunoaffinity chromatography. A purification of 280,000-fold over plasma with a specific activity over 5300 units/mg was achieved. Analyses of factor VIII using HPLC indicated a molecular mass of 280-340 kDa. Variation in the native mass may reflect heterogeneity of the protein due to associated lipid since structural analysis confirmed that factor VIII contained variable amounts of free fatty acids and diglycerides and triglycerides, but no phospholipids. Additional characterization by denaturing polyacrylamide gel electrophoresis under reducing conditions, followed by silver staining, showed a major single-chain polypeptide of factor VIII with a mass of approximately 260 kDa. To determine whether proteolyzed forms of factor VIII were present during fractionation, we analysed earlier steps in purification. This revealed additional species of factor VIII eluting faster than the single-chain form during chromatography on polyelectrolyte E5. Gel electrophoresis showed that these species of factor VIII consisted of multiple polypeptide chains, and partial peptide mapping using Staphylococcus aureus V8 protease indicated that they were structurally related. Monoclonal and hemophilic antibodies were used in immunoadsorption experiments to demonstrate that the purified factor VIII was composed predominantly of the 260-kDa factor VIII chain.

Effectiveness, specificity and safety of intranasal 1-deamino-8-D-arginine vasopressin treatment of normal blood donors

A study of the absorption of 300 micrograms of 1-deamino-8-D-arginine vasopressin (DDAVP) given intranasally to normal blood donors was carried out to determine (a) the correlation between plasma levels of DDAVP and the percent rise of factor VIII procoagulant activity (VIII:C) and (b) the efficacy, specificity and safety of this treatment in increasing the recovery of factor VIII:C in donated blood. The maximum drug concentration was highly correlated to the maximum percent rise of VIII:C (r = 0.858, p less than 0.01). A differentiated effect of DDAVP on increases of VIII:C, VIII:Ag, vWF:Ag and vWF multimers was observed. A transient rise of fibrinopeptide A from 5 to 16 ng/ml, 30 min post-DDAVP, was not accompanied by changes in fibrinogen levels or generation of detectable factor Xa or thrombin. DDAVP had no effect on the factor XII-dependent pathway of plasminogen activation, or on the donor's vital signs and hematological parameters. Side effects were minor and of short duration. Intranasal DDAVP treatment of blood donors is considered to be a practical means of improving the recovery of VIII:C from normal donors.

Disparity between one- and two-stage factor VIII assays in measuring VIIIC in heparinized plasma

The level of Factor VIII procoagulant activity (VIIIC) was found to be more than 30% higher in heparinized plasma than in citrated plasma from the same donor when determined by a one-stage assay (1.34 U/ml versus 1.0 U/ml). However, after Al(OH)3 adsorption and two-stage assay, the VIIIC levels were not significantly different for the two types of plasma (0.90 +/- 0.25 U/ml versus 0.82 +/- 0.23 U/ml). If a one-stage assay was employed after adsorption, a similar low result was obtained (0.92 +/- 0.21 U/ml versus 0.91 +/- 0.12 U/ml). This indicated that the adsorption step itself was responsible for the difference in results. Parallel analyses of other VIII markers demonstrated that more VIIIC antigen (VIIICAg) was removed by adsorption of heparinized rather than citrated plasma (0.33 U/ml versus 0.12 U/ml) although there was no difference in the level of VIII-related antigen (VIIIRAg). The results show that adsorption of heparinized plasma prior to either one- or two-stage assay leads to a greater loss of both VIIIC and VIIICAg activity than observed with citrated plasma and indicate that, when applied to heparin plasma the two-stage assay for VIIIC underestimates the actual VIIIC content.

Liquid-crystal thermographic mammography. A preliminary assessment of a controversial modality

Thermography is a simple and safe technique for examination of the breast. An analysis of 200 subjects examined by means of this non-invasive investigation demonstrates that it is a reasonably sensitive method. Its main applications are in the young symptomatic patient, mass surveys and the annual assessment of the 30-50-year age group.

Stability of VIII:C in plasma: the dependence on protease activity and calcium

Loss of Factor VIII procoagulant activity (VIII:C) following blood collection is a major problem in providing sufficient amounts for therapeutic use and biochemical analyses. We have examined the effects of inhibition of plasma proteases and maintenance of physiological calcium ion on plasma VIII:C stability. The addition of protease inhibitors such as benzamidine, phenylmethylsulfonyl fluoride (PMSF), aprotinin, or soybean trypsin inhibitor (SBTI) to CPD plasma provided no significant protection against decay of VIII:C activity. Neither the rate of decay in the first 24 hours nor the final VIII:C activity observed after storage for 48-72 hours were significantly altered. On the other hand, addition of DFP or heparin to CPD plasma resulted in a marked improvement in VIII:C stability over 24 hours. This demonstrated that these two inhibitors are effective in preventing VIII:C degradation during storage. In addition to protease inhibition, the importance of maintaining physiological calcium ion was demonstrated by 100% stabilization of VIII:C in heparin plasma. Plasma obtained from CPD plus heparin blood could also be stabilized provided free calcium ion levels were restored to physiological concentrations. The inactivation of VIII:C in CPD plus heparin plasma was completely reversible up to 4 hours after collection. Studies on the recovery of activity after recalcification of CPD plus heparin plasma provided kinetic data which support a renaturation process of VIII:C rather than one due to enzymatic activation. The use of a thrombin-specific chromogenic substrate revealed that after recalcification and during the recovery of VIII:C activity, there was no significant thrombin activity. Although the data suggest that proteolytic degradation plays some part in VIII:C decay, only the maintenance of physiologic calcium ion levels under cover of an effective non-chelating anticoagulant and protease inhibitor allows preservation of VIII:C activity.

Accumulative effect of DDAVP and heparin in increasing plasma factor VIII levels

DDAVP (l-desaminocysteine-(8-D-arginine)-vasopressin) produces a marked increase in plasma factor VIII procoagulant (F VIII:C) levels. Previously, we have reported that blood collected into heparin rather than into CPD anticoagulant results in higher starting levels of plasma F VIII:C activity. We therefore wished to determine whether the effects of these two agents were accumulative and whether they would result in any difference in the relative molecular distribution of F VIII:C. Blood was collected into CPD or heparin immediately before and 15 min after an intravenous dose of 0.2 micrograms/kg body weight of DDAVP. Pre-stimulation factor VIII levels were approximately 36% higher in heparinized plasma than in CPD plasma. Following DDAVP stimulation, the final factor VIII activity was increased 3.9-fold when either of the anticoagulants was used, with the heparin sample maintaining a 37% increase over the CPD sample. Column chromatography on Sepharose CL-6B of pre- and post-DDAVP plasma samples collected into either heparin or CPD indicated that there was no change in the relative distribution of the high and low molecular weight forms of F VIII:C. The heparinized sample showed the typical distribution of approximately 60% F VIII:C at void volume (Vo) and 40% at 2.3 Vo, suggesting that DDAVP-stimulated increases of plasma F VIII:C are equally distributed between the carrier and non-carrier associated F VIII:C activities.

Improved yields of factor VIII from heparinized plasma

The Factor VIII procoagulant activity in plasma, cryoprecipitate, and their polyethylene glycol (PEG) precipitates is markedly increased if blood is collected into heparin rather than into citrate phosphate dextrose (CPD). There is a 34% increase in the initial level of the Factor VIII activity in the heparinized plasma with 78% of this initial activity (184 U) recovered in the cryoprecipitated. As well, the stability of the Factor VIII activity is improved: after 24 h of incubation at 22 degrees C, 99% of the initial activity is retained in heparinized plasma whereas only 64% remains in CPD plasma. The cryoprecipitate prepared from heparinized plasma is equally stable after 24 h. The PEG concentrate prepared from the cryoprecipitate of heparinized plasma is increased to 128 U compared to only 54 U from CPD plasma. Relative recoveries were 531 U/l for heparinized plasma versus 215 U/l for CPD plasma. This represents a 147% increase in yield.

Needle localisation of non-palpable breast lesions

Localisation of non-palpable breast lesions using a simple inexpensive apparatus which can be constructed in most hospital workshops is described. A single-needle bi-plane technique is used. The details of the apparatus are given and the radiographic control of the insertion of the needle is described, particular emphasis being placed on practical details in order to assist those who are unfamiliar with the technique. The importance of localisation for the pathologist is emphasised.