423 research outputs found

    What is the Fourier Transform of a Spatial Point Process?

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    This paper determines how to define a discretely implemented Fourier transform when analysing an observed spatial point process. To develop this transform we answer four questions; first what is the natural definition of a Fourier transform, and what are its spectral moments, second we calculate fourth order moments of the Fourier transform using Campbell’s theorem. Third we determine how to implement tapering, an important component for spectral analysis of other stochastic processes. Fourth we answer the question of how to produce an isotropic representation of the Fourier transform of the process. This determines the basic spectral properties of an observed spatial point process

    Visualizing the Wavenumber Content of a Point Pattern

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    Spatial point patterns are a commonly recorded form of data in ecology, medicine, astronomy, criminology, epidemiology and many other application fields. One way to understand their second order dependence structure is via their spectral density function. However, unlike time series analysis, for point patterns such approaches are currently underutilized. In part, this is because the interpretation of the spectral representation of the underlying point processes is challenging. In this paper, we demonstrate how to band-pass filter point patterns, thus enabling us to explore the spectral representation of point patterns in space by isolating the signal corresponding to certain sets of wavenumbers

    Meta-Analysis of the Association between Transforming Growth Factor-Beta Polymorphisms and Complications of Coronary Heart Disease

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    Objective: To investigate the association between common transforming growth factor beta (TGF-β) single nucleotide polymorphisms (SNP) and significant complications of coronary heart disease (CHD).\ud \ud Method: We performed a meta-analysis of published case-control studies assessing the association of TGF-β SNPs with a range of CHD complications. A random effects model was used to calculate odds ratios and confidence intervals. Analyses were conducted for additive, dominant and recessive modes of inheritance.\ud \ud Results: Six studies involving 5535 cases and 2970 controls examining the association of common SNPs in TGF-β1 with CHD were identified. Applying a dominant model of inheritance, three TGF-β1 SNPs were significantly associated with CHD complications: The T alleles of rs1800469 (OR = 1.125, 95% CI 1.016–1.247, p = 0.031) and rs1800470 (OR = 1.146, 95% CI 1.026–1.279, p = 0.021); and the C allele of rs1800471 (OR = 1.207, 95% CI 1.037–1.406, p = 0.021).\ud \ud Conclusion: This meta-analysis suggests that common genetic polymorphisms in TGF-β1 are associated with complications of CHD

    Analysis of polymorphic TGFB1 codons 10, 25, and 263 in a German patient group with non-syndromic cleft lip, alveolus, and palate compared with healthy adults

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    BACKGROUND: Clefts of the lip, alveolus, and palate (CLPs) rank among the most frequent and significant congenital malformations. Leu10Pro and Arg25Pro polymorphisms in the precursor region and Thr263Ile polymorphism in the prodomain of the transforming growth factor β1 (TGF-β1) gene have proved to be crucial to predisposition of several disorders. METHODS: In this study, polymorphism analysis was performed by real-time polymerase chain reaction (LightCycler) and TGF-β1 levels determined by enzyme-linked immunosorbent assay. RESULTS: Only 2/60 Caucasian non-syndromic patients with CLP (3.3%) carried the Arg25Pro and another 2/60 patients (3.3%) the Thr263Ile genotypes, whereas, in a control group of 60 healthy Caucasian blood donors, these heterozygous genotypes were more frequent 16.7% having Arg25Pro (10/60; p < 0.035) and 10,0% having Thr263Ile (6/60), respectively. TGF-β1 levels in platelet-poor plasma of heterozygous Arg25Pro individuals were lower than those of homozygous members (Arg25Arg) in the latter group, but this discrepancy narrowly failed to be significant. Although polymorphisms in codon 10 and 25 were associated with each other, no difference was found between patients and controls concerning the Leu10Pro polymorphism. CONCLUSIONS: The genetic differences in codons 25 and 263 suggest that TGF-β1 could play an important role in occurrence of CLP, however, functional experiments will be required to confirm the mechanisms of disturbed development

    Identification of Heterozygous Single- and Multi-exon Deletions in IL7R by Whole Exome Sequencing

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    PURPOSE: We aimed to achieve a retrospective molecular diagnosis by applying state-of-the-art genomic sequencing methods to past patients with T-B+NK+ severe combined immunodeficiency (SCID). We included identification of copy number variations (CNVs) by whole exome sequencing (WES) using the CNV calling method ExomeDepth to detect gene alterations for which routine Sanger sequencing analysis is not suitable, such as large heterozygous deletions. METHODS: Of a total of 12 undiagnosed patients with T-B+NK+ SCID, we analyzed eight probands by WES, using GATK to detect single nucleotide variants (SNVs) and small insertions and deletions (INDELs) and ExomeDepth to detect CNVs. RESULTS: We found heterozygous single- or multi-exon deletions in IL7R, a known disease gene for autosomal recessive T-B+NK+ SCID, in four families (seven patients). In three families (five patients), these deletions coexisted with a heterozygous splice site or nonsense mutation elsewhere in the same gene, consistent with compound heterozygosity. In our cohort, about a quarter of T-B+NK+ SCID patients (26%) had such compound heterozygous IL7R deletions. CONCLUSIONS: We show that heterozygous IL7R exon deletions are common in T-B+NK+ SCID and are detectable by WES. They should be considered if Sanger sequencing fails to detect homozygous or compound heterozygous IL7R SNVs or INDELs

    Decorin and TGF-β(1 )polymorphisms and development of COPD in a general population

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    BACKGROUND: Decorin, an extracellular matrix (ECM) proteoglycan, and TGF-β(1 )are both involved in lung ECM turnover. Decorin and TGF-β(1 )expression are decreased respectively increased in COPD lung tissue. Interestingly, they act as each other's feedback regulator. We investigated whether single nucleotide polymorphisms (SNPs) in decorin and TGF-β(1 )underlie accelerated decline in FEV(1 )and development of COPD in the general population. METHODS: We genotyped 1390 subjects from the Vlagtwedde/Vlaardingen cohort. Lung function was measured every 3 years for a period of 25 years. We tested whether five SNPs in decorin (3'UTR and four intron SNPs) and three SNPs in TGF-β(1 )(3'UTR rs6957, C-509T rs1800469 and Leu10Pro rs1982073), and their haplotypes, were associated with COPD (last survey GOLD stage = II). Linear mixed effects models were used to analyze genotype associations with FEV(1 )decline. RESULTS: We found a significantly higher prevalence of carriers of the minor allele of the TGF-β(1 )rs6957 SNP (p = 0.001) in subjects with COPD. Additionally, we found a significantly lower prevalence of the haplotype with the major allele of rs6957 and minor alleles for rs1800469 and rs1982073 SNPs in TGF-β(1 )in subjects with COPD (p = 0.030), indicating that this association is due to the rs6957 SNP. TGF-β(1 )SNPs were not associated with FEV(1 )decline. SNPs in decorin, and haplotypes constructed of both TGF-β(1 )and decorin SNPs were not associated with development of COPD or with FEV(1 )decline. CONCLUSION: Our study shows for the first time that SNPs in decorin on its own or in interaction with SNPs in TGF-β(1 )do not underlie the disturbed balance in expression between these genes in COPD. TGF-β(1 )SNPs are associated with COPD, yet not with accelerated FEV(1 )decline in the general population

    Spatio-temporal Models of Lymphangiogenesis in Wound Healing

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    Several studies suggest that one possible cause of impaired wound healing is failed or insufficient lymphangiogenesis, that is the formation of new lymphatic capillaries. Although many mathematical models have been developed to describe the formation of blood capillaries (angiogenesis), very few have been proposed for the regeneration of the lymphatic network. Lymphangiogenesis is a markedly different process from angiogenesis, occurring at different times and in response to different chemical stimuli. Two main hypotheses have been proposed: 1) lymphatic capillaries sprout from existing interrupted ones at the edge of the wound in analogy to the blood angiogenesis case; 2) lymphatic endothelial cells first pool in the wound region following the lymph flow and then, once sufficiently populated, start to form a network. Here we present two PDE models describing lymphangiogenesis according to these two different hypotheses. Further, we include the effect of advection due to interstitial flow and lymph flow coming from open capillaries. The variables represent different cell densities and growth factor concentrations, and where possible the parameters are estimated from biological data. The models are then solved numerically and the results are compared with the available biological literature.Comment: 29 pages, 9 Figures, 6 Tables (39 figure files in total

    Association of Race and Ethnicity With COVID‐19 Outcomes in Rheumatic Disease: Data From the COVID‐19 Global Rheumatology Alliance Physician Registry

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    OBJECTIVE: Racial/ethnic minorities experience more severe outcomes of COVID-19 in the general United States (US) population. The aim of this study was to examine the association between race/ethnicity and COVID-19 hospitalization, ventilation status, and mortality in people with rheumatic disease. METHODS: US patients with rheumatic disease and COVID-19 entered into the COVID-19 Global Rheumatology Alliance physician registry March 24 - August 26, 2020 were included. Race/ethnicity was defined as white, Black, Latinx, Asian and other/mixed race. Outcomes included hospitalization, requirement for ventilatory support, and death. Multivariable regression models were used to estimate odds ratios (OR) and 95% confidence intervals controlling for age, sex, smoking, rheumatic disease diagnosis, comorbidities, medications taken prior to infection, and rheumatic disease activity. RESULTS: A total of 1,324 patients were included, of whom 36% were hospitalized and 6% died; 26% of hospitalized patients required mechanical ventilation. In multivariable models, Black (OR=2.74, 95% CI 1.90, 3.95), Latinx (OR=1.71, 95% CI 1.18, 2.49), and Asian (OR=2.69, 95% CI 1.16, 6.24) patients had higher odds of being hospitalized compared to white patients. Latinx patients also had three-fold increased odds of requiring ventilatory support (OR=3.25, 95% CI 1.75, 6.05). No differences in mortality based on race/ethnicity were found, though power may have been limited to detect associations. CONCLUSION: Similar to findings in the general US population, racial/ethnic minorities with rheumatic disease and COVID-19 had increased odds of hospitalization and ventilatory support. These results illustrate significant health disparities related to COVID-19 in people with rheumatic diseases. The rheumatology community should proactively address the needs of patients currently experiencing inequitable health outcomes during the pandemic

    Innate and adaptive type 2 immune cell responses in genetically controlled resistance to intestinal helminth infection

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    The nematode Heligmosomoides polygyrus is an excellent model for intestinal helminth parasitism. Infection in mice persists for varying lengths of time in different inbred strains, with CBA and C57BL/6 mice being fully susceptible, BALB/c partially so and SJL able to expel worms within 2–3 weeks of infection. We find that resistance correlates not only with the adaptive Th2 response, including IL-10 but with activation of innate lymphoid cell and macrophage populations. In addition, the titer and specificity range of the serum antibody response is maximal in resistant mice. In susceptible strains, Th2 responses were found to be counterbalanced by IFN-γ-producing CD4+ and CD8+ cells, but these are not solely responsible for susceptibility as mice deficient in either CD8+ T cells or IFN-γ remain unable to expel the parasites. Foxp3+ Treg numbers were comparable in all strains, but in the most resistant SJL strain, this population does not upregulate CD103 in infection, and in the lamina propria the frequency of Foxp3+CD103+ T cells is significantly lower than in susceptible mice. The more resistant SJL and BALB/c mice develop macrophage-rich IL-4Rα-dependent Type 2 granulomas around intestinal sites of larval invasion, and expression of alternative activation markers Arginase-1, Ch3L3 (Ym1) and RELM-α within the intestine and the peritoneal lavage was also strongly correlated with helminth elimination in these strains. Clodronate depletion of phagocytic cells compromises resistance of BALB/c mice and slows expulsion in the SJL strain. Thus, Type 2 immunity involves IL-4Rα-dependent innate cells including but not limited to a phagocyte population, the latter likely involving the action of specific antibodies

    Acupuncture for pain and osteoarthritis of the knee: a pilot study for an open parallel-arm randomised controlled trial

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    <p>Abstract</p> <p>Background</p> <p>There is some evidence that acupuncture for pain and osteoarthritis (OA) of the knee is more than a placebo, and short term clinical benefits have been observed when acupuncture is compared to usual care. However there is insufficient evidence on whether clinical benefits of acupuncture are sustained over the longer term. In this study our key objectives are to inform the design parameters for a fully powered pragmatic randomised controlled trial. These objectives include establishing potential recruitment rates, appropriate validated outcome measures, attendance levels for acupuncture treatment, loss to follow up and the sample size for a full scale trial.</p> <p>Methods</p> <p>Potential participants aged over 50 with pain and osteoarthritis of the knee were identified from a GP database. Eligible patients were randomised to either 'acupuncture plus usual care' and 'usual care' alone, with allocation appropriately concealed. Acupuncture consisted of up to 10 sessions usually weekly. Outcome measures included Western Ontario and McMaster Universities (WOMAC) index with the sample size for a full scale trial determined from the variance.</p> <p>Results</p> <p>From the GP database of 15,927 patients, 335 potential trial participants were identified and invited to participate. After screening responses, 78 (23%) were identified as eligible and 30 patients who responded most promptly were randomised to 'acupuncture plus usual care' (15 patients) and 'usual care' alone (15 patients). Attendance for acupuncture appointments was high at 90% of the maximum. Although the trial was not powered to detect significant changes in outcome, the WOMAC pain index showed a statistically significant reduction at 3 months in the acupuncture group compared to usual care. This was not sustained at 12 months. The sample size for a fully powered two-arm trial was estimated to be 350.</p> <p>Conclusion</p> <p>This pilot study provided the evidence that a fully powered study to explore the longer term impact of acupuncture would be worthwhile, and relevant design features for such a trial were determined.</p> <p>Trial registration number</p> <p>ISRCTN25134802.</p
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