1,415 research outputs found
Flow cytometric evaluation of red blood cells transformed with variable amounts of synthetic A and B glycolipids
Background: According to national guidelines or directives, monoclonal
ABO reagents may be required to detect Ax and B weak subgroup red blood
cells (RBCs). Many routine laboratories do not have access to naturallyoccurring
ABO subgroups that can be used as weak controls for these
reagents. Group O RBCs modified with synthetic analogs of blood group A
and/or B glycolipids (KODE technology) to mimic weak ABO subgroups
could be used for quality control purposes.
Aim: Extensive serological testing of KODE RBCs has previously been
performed. An extended evaluation of KODE RBCs using flow cytometry
was performed to explore the correlation between the concentrations of
synthetic glycolipids and A/B site density of the resulting RBCs. The aim of
this study was to examine if KODE RBCs mimic the distinct flow cytometric
patterns of naturally-occurring ABO subgroups.
Material and Methods: KODE RBCs were prepared according to a previously
decribed procedure [Frame et al., Transfusion 2007; 47: 876–82].
RBCs were modified with 15 different concentrations of synthetic glycolipids,
ranging from 1 mg/mL to 60 ng/mL for KODE-A and 5 mg/mL to
0.3 lg/mL for KODE-B. The concentration was decreased by doubling
dilution steps. Sensitive and specific flow cytometry [Hult & Olsson.
Transfusion 2006; 9S: 32A] was used to characterize and semiquantify the
synthetic A and B antigen levels on RBCs. Relevant control RBCs (A1, A2,
Ax, B, Bweak and O) were included in each run. For both KODE-A and KODE-B RBCs, repeat samples were produced for four selected concentrations
and all KODE batches were tested in triplicate.
Results: Flow cytometric testing of KODE RBCs modified with high
concentrations of synthetic glycolipids revealed a uniform and even
distribution of antigens in the cell population as shown by a single
narrow peak in the FACS histograms. When lower concentrations were
used, peaks tended to broaden to a pattern found in Ax and most B
subgroups indicating a more variable antigen site density on the cells in
the population. The concentrations of synthetic glycolipids that produced
KODE cells that resembled the naturally-occurring subgroup control RBCs
used in this study are ~2–4 lg/mL for KODE-A and ~10 lg/mL for KODEB.
Repeat testing demonstrated good correlation between flow cytometric
runs.
Discussion and Conclusion: Using very low amounts of synthetic
glycolipids, KODE-A and KODE-B RBCs can be made to mimic Ax and
Bweak subgroup control RBCs, respectively, according to this flow
cytometry method. With higher concentrations of synthetic glycolipids, the
KODE RBCs demonstrated a more uniform and even distribution of antigens
among the cells. This is in contrast to naturally-occurring subgroups
in which some cells express almost no A or B antigen whilst others have
close to normal levels. The reason for this is unknown. KODE RBCs obviously
lack A carrying glycoproteins but it is not fully understood to what
extent glycolipid versus glycoprotein epitopes contribute to the phenotype
of weak subgroups.
This study indicates that KODE RBCs with weak expression of A and/or B
antigen have characteristics compatible with use as quality controls for
monoclonal ABO reagents and could be a valuable addition in the
serological laboratory
Long-term social skills group training for children and adolescents with autism spectrum disorder: a randomized controlled trial
Social skills group training (SSGT) is widely used for intellectually able children and adolescents with autism spectrum disorder (ASD). Previous studies indicate small to moderate effects on social communication capacities. The duration of most available programs is relatively short, and extended training might lead to further improvement. This randomized controlled trial compared an extended 24-week version of the SSGT program KONTAKT with standard care. The weekly sessions gradually shifted in content from acquisition of new skills to real-world application of the acquired skills. A total of 50 participants with ASD (15 females; 35 males) aged 8–17 years were included. The study was conducted at two child and adolescent psychiatry outpatient units in Sweden. The primary outcome was the Social Responsiveness Scale–Second Edition (SRS-2) rated by parents and blinded teachers. Secondary outcomes included parent- and teacher-rated adaptive behaviors, trainer-rated global functioning and clinical severity, and self-reported child and caregiver stress. Assessments were made at baseline, posttreatment, and at 3-months follow-up. Parent-rated SRS-2 scores indicated large effects posttreatment [- 19.2; 95% CI - 29.9 to - 8.5; p < .001, effect size (ES) = 0.76], which were maintained at follow-up (- 20.7; 95% CI - 31.7 to - 9.7; p < .0001, ES = 0.82). These estimates indicate substantially larger improvement than previously reported for shorter SSGT. However, the effects on teacher-rated SRS-2 and most secondary outcomes did not reach statistical significance. Our results suggest added benefits of extended SSGT training, implying that service providers might reach better results by optimizing the delivery of SSGT
Genetic and Mechanistic Evaluation for the Mixed-Field Agglutination in B3 Blood Type with IVS3+5G>A ABO Gene Mutation
Background: The ABO blood type B3 is the most common B subtype in the Chinese population with a frequency of 1/900. Although IVS3+5G.A (rs55852701) mutation of B gene has been shown to associate with the development of B3 blood type, genetic and mechanistic evaluation for the unique mixed-field agglutination phenotype has not yet been completely addressed. Methodology/Principal Findings: In this study, we analyzed 16 cases of confirmed B3 individuals and found that IVS3+5G.A attributes to all cases of B3. RT-PCR analyses revealed the presence of at least 7 types of aberrant B3 splicing transcripts with most of the transcripts causing early termination and producing non-functional protein during translation. The splicing transcript without exon 3 that was predicted to generate functional B3 glycosyltransferase lacking 19 amino acids at the N-terminal segment constituted only 0.9 % of the splicing transcripts. Expression of the B3 cDNA with exon 3 deletion in the K562 erythroleukemia cells revealed that the B3 glycosyltransferase had only 40 % of B1 activity in converting H antigen to B antigen. Notably, the typical mixed-field agglutination of B3-RBCs can be mimicked by adding anti-B antibody to the K562-B3 cells. Conclusions/Significance: This study thereby demonstrates that both aberrant splicing of B transcripts and the reduced B3 glycosyltransferase activity contribute to weak B expression and the mixed-field agglutination of B3, adding to th
Psychosocial factors during the first year after a coronary heart disease event in cases and referents. Secondary Prevention in Uppsala Primary Health Care Project (SUPRIM)
<p>Abstract</p> <p>Background</p> <p>A large number of studies have reported on the psychosocial risk factor pattern prior to coronary heart disease events, but few have investigated the situation during the first year after an event, and none has been controlled. We therefore performed a case-referent study in which the prevalence of a number of psychosocial factors was evaluated.</p> <p>Methods</p> <p>Three hundred and forty-six coronary heart disease male and female cases no more than 75 years of age, discharged from hospital within the past 12 months, and 1038 referents from the general population, matched to the cases by age, sex and place of living, received a postal questionnaire in which information on lifestyle, psychosocial and quality of life measures were sought.</p> <p>Results</p> <p>The cases were, as expected, on sick leave to a larger extent than the referents, reported poorer fitness, poorer perceived health, fewer leisure time activities, but unexpectedly reported better social support, and more optimistic views of the future than the referents. There were no significant case-referent differences in everyday life stress, stressful life events, vital exhaustion, depressive mood, coping or life orientation test. However, women reported less favourable situations than men regarding stressful life events affecting others, vital exhaustion, depressive mood, coping, self-esteem, sleep, and symptom reporting, and female cases reported the most unfavourable situation of all groups.</p> <p>Conclusion</p> <p>In this first controlled study of the situation during the first year after a CHD event disease and gender status both appeared to be determinants of psychological well-being, with gender status apparently the strongest. This may have implications for cardiac rehabilitation programmes.</p
Researchers’ attitudes to the 3Rs - An upturned hierarchy?
Animal use in biomedical research is generally justified by its potential benefits to the health of humans, or other animals, or the environment. However, ethical acceptability also requires scientists to limit harm to animals in their research. Training in laboratory animal science (LAS) helps scientists to do this by promoting best practice and the 3Rs. This study evaluated scientists’ awareness and application of the 3Rs, and their approach to other ethical issues in animal research. It was based on an online survey of participants in LAS courses held in eight venues in four European countries: Portugal (Porto, Braga), Germany (Munich, Heidelberg), Switzerland (Basel, Lausanne, Zurich), and Denmark (Copenhagen). The survey questions were designed to assess general attitudes to animal use in biomedical research, Replacement alternatives, Reduction and Refinement conflicts, and harm-benefit analysis. The survey was conducted twice: immediately before the course (‘BC’, N = 310) and as a follow-up six months after the course (‘AC’, N = 127). While courses do appear to raise awareness of the 3Rs, they had no measurable effect on the existing low level of belief that animal experimentation can be fully replaced by non-animal methods. Most researchers acknowledged ethical issues with their work and reported that they discussed these with their peers. The level of an animal’s welfare, and especially the prevention of pain, was regarded as the most pressing ethical issue, and as more important than the number of animals used or the use of animals as such. Refinement was considered more feasible than Replacement, as well as more urgent, and was also favoured over Reduction. Respondents in the survey reversed the ‘hierarchy’ of the 3Rs proposed by their architects, Russell and Burch, prioritizing Refinement over Reduction, and Reduction over Replacement. This ordering may conflict with the expectations of the public and regulators.</div
A possible role for miRNA silencing in disease phenotype variation in Swedish transthyretin V30M carriers
Our results are the first to show the presence of a 3'UTR polymorphism on the V30M haplotype in Swedish carriers, which can serve as a miRNA binding site potentially leading to down-regulated expression from the mutated TTR allele. This finding may be related to the low penetrance and high age at onset of the disease observed in the Swedish patient population
Enhanced Platelet Activation Mediates the Accelerated Angiogenic Switch in Mice Lacking Histidine-Rich Glycoprotein
BACKGROUND: The heparin-binding plasma protein histidine-rich glycoprotein (HRG; alternatively, HRGP/HPRG) can suppress tumor angiogenesis and growth in vitro and in vivo. Mice lacking the HRG gene are viable and fertile, but have an enhanced coagulation resulting in decreased bleeding times. In addition, the angiogenic switch is significantly enhanced in HRG-deficient mice. METHODOLOGY/PRINCIPAL FINDINGS: To address whether HRG deficiency affects tumor development, we have crossed HRG knockout mice with the RIP1-Tag2 mouse, a well established orthotopic model of multistage carcinogenesis. RIP1-Tag2 HRG(-/-) mice display significantly larger tumor volume compared to their RIP1-Tag2 HRG(+/+) littermates, supporting a role for HRG as an endogenous regulator of tumor growth. In the present study we also demonstrate that platelet activation is increased in mice lacking HRG. To address whether this elevated platelet activation contributes to the increased pathological angiogenesis in HRG-deficient mice, they were rendered thrombocytopenic before the onset of the angiogenic switch by injection of the anti-platelet antibody GP1bα. Interestingly, this treatment suppressed the increase in angiogenic neoplasias seen in HRG knockout mice. However, if GP1bα treatment was initiated at a later stage, after the onset of the angiogenic switch, no suppression of tumor growth was detected in HRG-deficient mice. CONCLUSIONS: Our data show that increased platelet activation mediates the accelerated angiogenic switch in HRG-deficient mice. Moreover, we conclude that platelets play a crucial role in the early stages of tumor development but are of less significance for tumor growth once angiogenesis has been initiated
A population-based cohort study on sun habits and endometrial cancer
Background:No large cohort study has examined the risk of endometrial cancer in relation to sun exposure.Methods:A population-based cohort study of 29 508 women who answered a questionnaire in 1990-92, of whom 24 098 responded to a follow-up enquiry in 2000-02. They were followed for an average of 15.5 years.Results:Among the 17 822 postmenopausal women included, 166 cases of endometrial cancer were diagnosed. We used a multivariate Cox regression analysis adjusting for age and other selected demographic variables to determine the risk of endometrial cancer. Women using sun beds >3 times per year reduced their hazard risk (HR) by 40% (0.6, 95% confidence interval (CI) 0.4-0.9) or by 50% when adjusting for body mass index or physical activity (HR 0.5, 95% CI 0.3-0.9), and those women who were sunbathing during summer reduced their risk by 20% (HR 0.8 95% CI 0.5-1.5) compared with women who did not expose themselves to the sun or to artificial sun (i.e., sun beds).Conclusion:Exposure to artificial sun by the use of sun beds >3 times per year was associated with a 40% reduction in the risk of endometrial cancer, probably by improving the vitamin D levels during winter.British Journal of Cancer advance online publication, 23 June 2009; doi:10.1038/sj.bjc.6605149 www.bjcancer.com
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