Hematopoietic stem cell quiescence maintained by p21cip1/waf1

Relative quiescence is a defining characteristic of hematopoietic stem cells, while their progeny have dramatic proliferative ability and inexorably move toward terminal differentiation. The quiescence of stem cells has been conjectured to be of critical biologic importance in protecting the stem cell compartment, which we directly assessed using mice engineered to be deficient in the G1 checkpoint regulator, cyclin-dependent kinase inhibitor, p21cip1/waf1 (p21). In the absence of p21, hematopoietic stem cell proliferation and absolute number were increased under normal homeostatic conditions. Exposing the animals to cell cycle-specific myelotoxic injury resulted in premature death due to hematopoietic cell depletion. Further, self-renewal of primitive cells was impaired in serially transplanted bone marrow from p21-/- mice, leading to hematopoietic failure. Therefore, p21 is the molecular switch governing the entry of stem cells into the cell cycle, and in its absence, increased cell cycling leads to stem cell exhaustion. Under conditions of stress, restricted cell cycling is crucial to prevent premature stem cell depletion and hematopoietic death.

A nucleotide substitution in the promoter of human angiotensinogen is associated with essential hypertension and affects basal transcription in vitro

In earlier studies, we provided statistical evidence that individual differences in the angiotensinogen gene, the precursor of the vasoactive hormone angiotensin II, constitute inherited predispositions to essential hypertension in humans. We have now identified a common variant in the proximal promoter, the presence of an adenine, instead of a guanine, 6 bp upstream from the initiation site of transcription, in significant association with the disorder. Tests of promoter activity and DNA binding studies with nuclear proteins suggest that this nucleotide substitution affects the basal transcription rate of the gene. These observations provide some biological insight about the possible mechanism of a genetic predisposition to essential hypertension; they may also have important evolutionary implications.

CCAAT/enhancer binding protein alpha is a regulatory switch sufficient for induction of granulocytic development from bipotential myeloid progenitors

The transcription factor CCAAT/enhancer binding protein alpha (C/EBPalpha) regulates a number of myeloid cell-specific genes. To delineate the role of C/EBPalpha in human granulopoiesis, we studied its expression and function in human primary cells and bipotential (granulocytic/monocytic) myeloid cell lines. We show that the expression of C/EBPalpha initiates with the commitment of multipotential precursors to the myeloid lineage, is specifically upregulated during granulocytic differentiation, and is rapidly downregulated during the alternative monocytic pathway. Conditional expression of C/EBPalpha alone in stably transfected bipotential cells triggers neutrophilic differentiation, concomitant with upregulation of the granulocyte-specific granulocyte colony-stimulating factor receptor and secondary granule protein genes. Moreover, induced expression of C/EBPalpha in bipotential precursors blocks their monocytic differentiation program. These results indicate that C/EBPalpha serves as a myeloid differentiation switch acting on bipotential precursors and directing them to mature to granulocytes.

Monitoring mRNA expression by polymerase chain reaction: the "primer-dropping" method

We have developed a method to monitor mRNA expression that is based upon the reverse transcriptase-polymerase chain reaction (RT-PCR) and includes multiple sets of primer pairs in coamplification reactions. To observe relative changes in mRNA steady-state levels, each target in a multiplex reaction was amplified to within a predetermined range by using PCR cycle numbers specific for each target. Optimal PCR cycle numbers for target templates were determined by preliminary titration experiments performed using the "primer-dropping" method. By employing this method, the overall amplification reaction was limited, permitting the PCR products to remain within the exponential range of the amplification curve and yet be detectable on ethidium bromide-stained gels. We demonstrated the utility of this method by monitoring the expression kinetics of cyclins A, B1, D1, and E, and of the immediate-early genes c-fos, c-myc, and beta-actin. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was included in the multiplex reactions as an endogenous internal standard to control for variations in product abundances due to differences in individual RT and PCR reaction efficiencies. Changes in gene expression of less than twofold to greater than 75-fold were readily distinguished.

Stem cell repopulation efficiency but not pool size is governed by p27(kip1)

Sustained blood cell production requires preservation of a quiescent, multipotential stem cell pool that intermittently gives rise to progenitors with robust proliferative potential. The ability of cells to shift from a highly constrained to a vigorously active proliferative state is critical for maintaining stem cells while providing the responsiveness necessary for host defense. The cyclin-dependent kinase inhibitor (CDKI), p21(cip1/waf1) (p21) dominates stem cell kinetics. Here we report that another CDKI, p27(kip1) (p27), does not affect stem cell number, cell cycling, or self-renewal, but markedly alters progenitor proliferation and pool size. Therefore, distinct CDKIs govern the highly divergent stem and progenitor cell populations. When competitively transplanted, p27-deficient stem cells generate progenitors that eventually dominate blood cell production. Modulating p27 expression in a small number of stem cells may translate into effects on the majority of mature cells, thereby providing a strategy for potentiating the impact of transduced cells in stem cell gene therapy.

Elements of a paracrine tubular renin-angiotensin system along the entire nephron

The renin-angiotensin system is a major regulator of body sodium, predominantly through the actions of intrarenal angiotensin II of unclear origin. We show that polarized epithelium of the proximal tubule synthesizes and secretes angiotensinogen at its apical side and that the protein can be detected in urine as a function of dietary sodium. Furthermore, we demonstrate that renin is expressed and secreted in a restricted nephron segment, the connecting tubule, also in a sodium-dependent fashion. A paracrine renin-angiotensin system operating along the entire nephron may contribute to long-term arterial pressure regulation by integrating distant tubular sodium-reabsorbing functions.

1,25(OH)2 vitamin D3, and retinoic acid antagonize endothelin-stimulated hypertrophy of neonatal rat cardiac myocytes

1,25(OH)2 Vitamin D3 (VD3) and retinoic acid (RA) function as ligands for nuclear receptors which regulate transcription. Though the cardiovascular system is not thought to represent a classical target for these ligands, it is clear that both cardiac myocytes and vascular smooth muscle cells respond to these agents with changes in growth characteristics and gene expression. In this study we demonstrate that each of these ligands suppresses many of the phenotypic correlates of endothelin-induced hypertrophy in a cultured neonatal rat cardiac ventriculocyte model. Each of these agents reduced endothelin-stimulated ANP secretion in a dose-dependent fashion and the two in combination proved to be more effective than either agent used alone (VD3: 49%; RA:52%; VD3 + RA:80% inhibition). RA, at concentrations known to activate the retinoid X receptor, and, to a lesser extent, VD3 effected a reduction in atrial natriuretic peptide, brain natriuretic peptide, and alpha-skeletal actin mRNA levels. Similar inhibition (VD3:30%; RA:33%; VD3 + RA:59% inhibition) was demonstrated when cells transfected with reporter constructs harboring the relevant promoter sequences were treated with VD3 and/or RA for 48 h. These effects were not accompanied by alterations in endothelin-induced c-fos, c-jun, or c-myc gene expression, suggesting either that the inhibitory locus responsible for the reduction in the mRNA levels lies distal to the activation of the immediate early gene response or that the two are not mechanistically coupled. Both VD3 and RA also reduced [3H]leucine incorporation (VD3:30%; RA:33%; VD3 + RA:45% inhibition) in endothelin-stimulated ventriculocytes and, once again, the combination of the two was more effective than either agent used in isolation. Finally, 1,25(OH)2 vitamin D3 abrogated the increase in cell size seen after endothelin treatment. These findings suggest that the liganded vitamin D and retinoid receptors are capable of modulating the hypertrophic process in vitro and that agents acting through these or similar signaling pathways may be of value in probing the molecular mechanisms underlying hypertrophy.

Temporal mapping of gene expression levels during the differentiation of individual primary hematopoietic cells

A hierarchical order of gene expression has been proposed to control developmental events in hematopoiesis, but direct demonstration of the temporal relationships between regulatory gene expression and differentiation has been difficult to achieve. We modified a single-cell PCR method to detect 2-fold changes in mRNA copies per cell (dynamic range, 250-250,000 copies/cell) and used it to sequentially quantitate gene expression levels as single primitive (CD34+,CD38-) progenitor cells underwent differentiation to become erythrocytes, granulocytes, or monocyte/macrophages. Markers of differentiation such as CD34 or cytokine receptor mRNAs and transcription factors associated with their regulation were assessed. All transcription factors tested were expressed in multipotent progenitors. During lineage-specific differentiation, however, distinct patterns of expression emerged. SCL, GATA-2, and GATA-1 expression sequentially extinguished during erythroid differentiation. PU.1, AML1B, and C/EBP alpha expression profiles and their relationship to cytokine receptor expression in maturing granulocytes could be distinguished from similar profiles in monocytic cells. These data characterize the dynamics of gene expression accompanying blood cell development and define a signature gene expression pattern for specific stages of hematopoietic differentiation.

Downregulation of transcription factor SOX2 in cancer stem cells suppresses growth and metastasis of lung cancer

Background:

The cancer stem cell hypothesis suggests that neoplastic clones are maintained exclusively by a small subpopulation of cells, which have indefinite proliferation and differentiation potentials and give rise to phenotypically diverse cancer cells. Cancer stem cells have been isolated by their ability to efflux Hoechst 33342 dye and are referred to as the ‘side population’ (SP).

Methods and results:

The Hoechst efflux assay was used to isolate and characterize the SP from murine D121 lung carcinoma cells. Here, we demonstrated that D121-SP cells contain cancer stem cell characteristics, that is, upregulation of the transcription factors SOX2 and Oct 4 in D121-SP cells. In addition, the migration of D121-SP was decreased, and apoptosis of D121-SP was upregulated following knocking down of SOX2 in D121 cells. Importantly, downregulation of SOX2 in D121 cells markedly suppressed their metastatic potential in syngeneic mice.

Conclusions:

These results suggest that the SP is an enriched source of lung tumour cells with stem cell properties and that SOX2 has an important role in maintaining stem cell properties and functions that may be a potential target for effective lung cancer therapy.

Liriodendron genome sheds light on angiosperm phylogeny and species-pair differentiation

The genus Liriodendron belongs to the family Magnoliaceae, which resides within the magnoliids, an early diverging lineage of the Mesangiospermae. However, the phylogenetic relationship of magnoliids with eudicots and monocots has not been conclusively resolved and thus remains to be determined1-6. Liriodendron is a relict lineage from the Tertiary with two distinct species-one East Asian (L. chinense (Hemsley) Sargent) and one eastern North American (L. tulipifera Linn)-identified as a vicariad species pair. However, the genetic divergence and evolutionary trajectories of these species remain to be elucidated at the whole-genome level7. Here, we report the first de novo genome assembly of a plant in the Magnoliaceae, L. chinense. Phylogenetic analyses suggest that magnoliids are sister to the clade consisting of eudicots and monocots, with rapid diversification occurring in the common ancestor of these three lineages. Analyses of population genetic structure indicate that L. chinense has diverged into two lineages-the eastern and western groups-in China. While L. tulipifera in North America is genetically positioned between the two L. chinense groups, it is closer to the eastern group. This result is consistent with phenotypic observations that suggest that the eastern and western groups of China may have diverged long ago, possibly before the intercontinental differentiation between L. chinense and L. tulipifera. Genetic diversity analyses show that L. chinense has tenfold higher genetic diversity than L. tulipifera, suggesting that the complicated regions comprising east-west-orientated mountains and the Yangtze river basin (especially near 30° N latitude) in East Asia offered more successful refugia than the south-north-orientated mountain valleys in eastern North America during the Quaternary glacial period.

CXCR-4 desensitization is associated with tissue localization of hemopoietic progenitor cells

The chemokine stroma-derived factor (SDF)-1, and its receptor, CXCR-4, have been shown to be essential for the translocation of hemopoietic stem cells from the fetal liver to the bone marrow (BM). We hypothesized that if CXCR-4 plays a crucial role in the localization of human hemopoiesis, stem cells from distinct tissue sources should demonstrate distinct CXCR-4 expression or signaling profiles. CD34(+) cells from BM were compared with blood: either mobilized peripheral blood or umbilical cord blood. Unexpectedly, significantly higher levels of CXCR-4 surface expression on CD34(+) cells from blood sources, mobilized peripheral blood, or cord blood were observed compared with BM (p = 0.0005 and p = 0.002, respectively). However, despite lower levels of CXCR-4, responsiveness of the cells to SDF-1 as measured by either calcium flux or transmigration was proportionally greatest in cells derived from BM. Further, internalization of CXCR-4 in response to ligand, associated with receptor desensitization, was significantly lower on BM-derived cells. Therefore, preserved chemokine receptor signaling was highly associated with marrow rather than blood localization. To test the functional effects of perturbing CXCR-4 signaling, adult mice were exposed to the methionine-SDF-1beta analog that induces prolonged down-regulation/desensitization of CXCR-4 and observed mobilization of Lin(-), Sca-1(+), Thy-1(low), and c-kit(+) hemopoietic progenitor cells to the peripheral blood with a >30-fold increase compared with PBS control (p = 0.0007 day 1 and p = 0.004 day 2). These data demonstrate that CXCR-4 expression and function can be dissociated in progenitor cells and that desensitization of CXCR-4 induces stem cell entry into the circulation.

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Pierro GA, Polese G, Ruggles T, Sarangi T, Savin A, Sharma A, Smith N, Smith WH, Taylor D, Woods N. Event generator tunes obtained from underlying event and multiparton scattering measurements

New sets of parameters ("tunes") for the underlying-event (UE) modelling of the pythia8, pythia6 and herwig++ Monte Carlo event generators are constructed using different parton distribution functions. Combined fits to CMS UE proton-proton ([Formula: see text]) data at [Formula: see text] and to UE proton-antiproton ([Formula: see text]) data from the CDF experiment at lower [Formula: see text], are used to study the UE models and constrain their parameters, providing thereby improved predictions for proton-proton collisions at 13[Formula: see text]. In addition, it is investigated whether the values of the parameters obtained from fits to UE observables are consistent with the values determined from fitting observables sensitive to double-parton scattering processes. Finally, comparisons are presented of the UE tunes to "minimum bias" (MB) events, multijet, and Drell-Yan ([Formula: see text] lepton-antilepton+jets) observables at 7 and 8[Formula: see text], as well as predictions for MB and UE observables at 13[Formula: see text].

High-dose thiotepa, busulfan, cyclophosphamide and ASCT without whole-brain radiotherapy for poor prognosis primary CNS lymphoma

Treatment of primary central nervous system lymphoma (PCNSL) with combined high-dose methotrexate (HD-MTX)-based chemotherapy and whole-brain radiotherapy (WBRT) is associated with severe neurotoxicity, but high relapse rates are associated with the use of either modality alone. In an attempt to improve upon these dismal results, we treated seven PCNSL patients with HD-MTX-based induction therapy followed by thiotepa, busulfan, cyclophosphamide (TBC), and autologous stem cell transplant (ASCT), without WBRT. Six of these patients had at least one of the following poor prognostic features: Karnofsky performance status (KPS) <or=50%, age >60 years, or relapsed disease. All but one patient tolerated the treatment well and experienced improvements in neurological function and overall performance status post-transplant. No treatment-induced neurotoxicity (dementia, ataxia, and incontinence) was observed although the follow-up is short. One early treatment-related death occurred in a patient with multiple comorbid medical conditions. The other six patients achieved a complete response (CR) after TBC and ASCT. Five patients are currently alive and relapse-free at 5, 8, 24, 36, and 42 months from diagnosis. One additional patient relapsed and died 33 months after diagnosis. Two of the seven patients received TBC/ASCT as the only treatment after disease progression following their initial chemotherapy and both remain relapse-free at the time of this report, 22 and 31 months post-TBC/ASCT. In conclusion, prolonged CR can be attained after chemotherapy-only treatment of poor prognosis PCNSL. Furthermore, this small series suggests that high-dose chemotherapy for PCNSL should include drugs that penetrate the CNS such as busulfan and thiotepa rather than standard lymphoma regimens such as BEAM.

Attributions of cause and recurrence in long-term breast cancer survivors

Women are bombarded with information about the purported causes and the prevention of breast cancer. This survey sought to determine to what women survivors of breast cancer attributed the cause and lack of recurrence of their breast cancer, and whether these views were associated with specific health behaviors.

METHODS

Women who had survived breast cancer without recurrence for at least 2 years were surveyed by mail about their views on the cause and lack of recurrence of their breast cancer. They were also asked to estimate their personal risk of cancer recurrence, report on their health behaviors, describe what advice they would give to women newly diagnosed with breast cancer, and what they would change if they had to relive their breast cancer experience.

RESULTS

378 (75.6%) women breast cancer survivors responded who had been recurrence free for a mean of 8.6+/-11.8 years. Women (n=322) who responded to the question about the cause of breast cancer attributed it to stress (42.2%), genetics (26.7%), environment (25.5%), hormones (23.9%), don't know (16.5%), diet (15.5%), and breast trauma (2.8%). Women (n=330) who responded to the question about what prevented cancer recurrence attributed it to positive attitude (60.0%), diet (50.0%), healthy lifestyle (40.3%), exercise (39.4%), stress reduction (27.9%), prayer (26.4%), complementary therapies (11.2%), don't know (5.1 %), luck (3.9%), and tamoxifen (3.9%). Most women felt their recurrence risk was average (44.8%), or below average (35.8%). Some attributions of breast cancer cause or lack of recurrence were associated with specific health behaviors. The majority of women survivors would advise other women with breast cancer to be positive, and if they had to relive their cancer experience they would take more control of their treatment.

DISCUSSION

Despite lack of evidence substantiating stress as a cause of breast cancer, many breast cancer survivors believed stress caused their cancer. An even higher percentage of survivors believed their positive attitude had prevented breast cancer recurrence and they would advise other women with breast cancer accordingly. Attribution beliefs clearly affected survivors' health behaviors.

CONCLUSION

Healthcare providers should consider the personal beliefs of patients about cancer cause and recurrence, which may be at variance with scientific evidence. This may assist in framing the management of patients in personally meaningful ways, which may increase health behaviors, adherence, satisfaction and quality of life. Whether it will increase survival remains unknown.

C-terminal fragments of the alpha 1C (CaV1.2) subunit associate with and regulate L-type calcium channels containing C-terminal-truncated alpha 1C subunits

L-type Ca(2+) channels in native tissues have been found to contain a pore-forming alpha(1) subunit that is often truncated at the C terminus. However, the C terminus contains many important domains that regulate channel function. To test the hypothesis that C-terminal fragments may associate with and regulate C-terminal-truncated alpha(1C) (Ca(V)1.2) subunits, we performed electrophysiological and biochemical experiments. In tsA201 cells expressing either wild type or C-terminal-truncated alpha(1C) subunits in combination with a beta(2a) subunit, truncation of the alpha(1C) subunit by as little as 147 amino acids led to a 10-15-fold increase in currents compared with those obtained from control, full-length alpha(1C) subunits. Dialysis of cells expressing the truncated alpha(1C) subunits with C-terminal fragments applied through the patch pipette reconstituted the inhibition of the channels seen with full-length alpha(1C) subunits. In addition, C-terminal deletion mutants containing a tethered C terminus also exhibited the C-terminal-induced inhibition. Immunoprecipitation assays demonstrated the association of the C-terminal fragments with truncated alpha(1C) subunits. In addition, glutathione S-transferase pull-down assays demonstrated that the C-terminal inhibitory fragment could associate with at least two domains within the C terminus. The results support the hypothesis the C- terminal fragments of the alpha(1C) subunit can associate with C-terminal-truncated alpha(1C) subunits and inhibit the currents through L-type Ca(2+) channels.

Structured three-dimensional co-culture of mesenchymal stem cells with chondrocytes promotes chondrogenic differentiation without hypertrophy

OBJECTIVE

This study investigated a novel approach to induce chondrogenic differentiation of human mesenchymal stem cells (hMSC). We hypothesized that a structured three-dimensional co-culture using hMSC and chondrocytes would provide chondroinductive cues to hMSC without inducing hypertrophy.

METHOD

In an effort to promote optimal chondrogenic differentiation of hMSC, we created bilaminar cell pellets (BCPs), which consist of a spherical population of hMSC encased within a layer of juvenile chondrocytes (JC). In addition to histologic analyses, we examined proteoglycan content and expression of chondrogenic and hypertrophic genes in BCPs, JC pellets, and hMSC pellets grown in the presence or absence of transforming growth factor-β (TGFβ) following 21 days of culture in either growth or chondrogenic media.

RESULTS

In either growth or chondrogenic media, we observed that BCPs and JC pellets produced more proteoglycan than hMSC pellets treated with TGFβ. BCPs and JC pellets also exhibited higher expression of the chondrogenic genes Sox9, aggrecan, and collagen 2A1, and lower expression of the hypertrophic genes matrix metalloproteinase-13, Runx2, collagen 1A1, and collagen 10A1 than hMSC pellets. Histologic analyses suggest that JC promote chondrogenic differentiation of cells in BCPs without hypertrophy. Furthermore, when cultured in hypoxic and inflammatory conditions intended to mimic the injured joint microenvironment, BCPs produced significantly more proteoglycan than either JC pellets or hMSC pellets.

CONCLUSION

The BCP co-culture promotes a chondrogenic phenotype without hypertrophy and, relative to pellet cultures of hMSCs or JCs alone, is more resistant to the adverse conditions anticipated at the site of articular cartilage repair.

Selection of reference genes for quantitative gene expression studies in Platycladus orientalis (Cupressaceae) Using real-time PCR

Platycladus orientalis is a tree species that is highly resistant, widely adaptable, and long-lived, with lifespans of even thousands of years. To explore the mechanisms underlying these characteristics, gene expressions have been investigated at the transcriptome level by RNA-seq combined with a digital gene expression (DGE) technique. So, it is crucial to have a reliable set of reference genes to normalize the expressions of genes in P. orientalis under various conditions using the most accurate and sensitive method of quantitative real-time PCR (qRT-PCR). In this study, we selected 10 reference gene candidates from transcriptome data of P. orientalis, and examined their expression profiles by qRT-PCR using 29 different samples of P. orientalis, which were collected from plants of different ages, different tissues, and plants subjected to different treatments including cold, heat, salinity, polyethylene glycol (PEG), and abscisic acid (ABA). Three analytical software packages (geNorm, Bestkeeper, and NormFinder) were used to assess the stability of gene expression. The results showed that ubiquitin-conjugating enzyme E2 (UBC) and alpha-tubulin (aTUB) were the optimum pair of reference genes at all developmental stages and under all stress conditions. ACT7 was the most stable gene across different tissues and cold-treated samples, while UBQ was the most stably expressed reference gene for NaCl- and ABA-treated samples. In parallel, aTUB and UBC were used singly or in combination as reference genes to examine the expression levels of NAC (a homolog of AtNAC2) in plants subjected to various treatments with qRT-PCR. The results further proved the reliability of the two selected reference genes. Our study will benefit future research on the expression of genes in response to stress/senescence in P. orientalis and other members of the Cupressaceae.

The influence of obesity on primary total hip arthroplasty outcomes: A meta-analysis of prospective cohort studies

BACKGROUND

Whether or not, obesity negatively influencing the outcomes of primary total hip arthroplasty (THA) remains a controversial issue. Though observational studies focused on this topic, the reported conclusions remain inconsistent. Therefore, we performed a meta-analysis of prospective cohort studies to evaluate if obesity negatively affects: (1) the overall complication rate (incidence of dislocation, deep infection and osteolysis); (2) functional outcome; (3) operative time and stay duration in hospital for the primary THA.

METHODS

We searched the PubMed, Embase, Web of Science, and the Cochrane Library until July 2014 to identify the eligible prospective studies. The Newcastle Ottawa Scale (NOS) was used for quality assessment of the included studies. We extracted and pooled the data. As for continuous data, mean difference (MD) was calculated; for dichotomous variables, we calculated a weighted relative risk (RR) with its 95% confidence interval. Heterogeneity was evaluated using I(2) statistics. P ≤ 0.05 was thought to be significant.

RESULTS

Fifteen studies were eligible for data extraction, which involved 11,271 total hip arthroplasties. The pooled data of complication rate demonstrated that obese patients suffered higher rates of complication (RR: 1.68, 95% CI 1.23 to 2.30, P = 0.0004), dislocation (RR: 2.08, 95% CI 1.54 to 2.81, P < 0.0001) and deep infection (RR: 2.92, 95% CI 0.74 to 11.49, P = 0.13). For the functional result, obese patients acquired relatively lower Harris Hip Score than non-obese patients (MD: -2.75, 95% CI -4.77 to -0.6), no difference was found regarding Oxford Hip Score (MD: -0.46, 95% CI -2.18 to 1.26, P = 0.60). Obese patients compared to non-obese patients showed an increase duration of operation (MD: 10.67, 95% CI 3.00 to 18.35, P = 0.006). However, no significant difference was found in the length of stay in hospital between obese and non-obese patients (MD: -0.16, 95% CI -0.34 to 0.02, P = 0.08).

CONCLUSIONS

This meta-analysis of prospective cohort studies demonstrates that obesity negatively influences the overall complication rate, dislocation rate, functional outcome and operative time of primary total hip arthroplasty.

Long-term breast cancer survivors: confidentiality, disclosure, effects on work and insurance

As more women are diagnosed with breast cancer, more will survive the illness from a few years to a lifetime. This study sought to determine the experience of Canadian breast cancer survivors with respect to the impact of cancer on confidentiality, work and insurance.

METHOD

Women who had survived breast cancer without recurrence for at least 2 years completed a mail survey about the effect of their illness on confidentiality, disclosure, work and insurance.

RESULTS

378 (75.6%) women breast cancer survivors responded to the survey. Their mean age was 61.0+/-10.9 years, and 67.6% had been recurrence free for more than 5 years. The majority of women rated hospital staff, family doctors, family, friends, and support groups at the highest possible level of confidentiality. Over 70% of survivors disclosed their diagnosis to friends, children, siblings, and partners, while over 50% disclosed to work colleagues and supervisors. However, over 40% felt cancer had altered their priorities or progress at work, and 5% were afraid to change jobs in case they became ill again. There was a lack of knowledge about insurance but, of the types of insurance identified, life insurance (17.9%), extended health insurance (7.7%), and private disability insurance (4.4%) were reported to have been refused or offered only with higher premiums as a result of a past diagnosis of breast cancer.

DISCUSSION

A substantial minority of women perceived that cancer had substantially affected their personal and work lives. Although most felt their illness confidentiality was well protected and they disclosed freely to family, friends, and work, over 40% of women survivors reported that cancer had affected their work in various ways, and nearly 20% identified insurance problems. It appears that disclosure sometimes results in negative work and insurance experiences.

CONCLUSIONS

Health professionals and cancer survivors should engage in education about the potential positive and negative effects of disclosure, and advocacy against cancer-based work and insurance discrimination.

Extraction and validation of a new set of CMS pythia8 tunes from underlying-event measurements

New sets of CMS underlying-event parameters ("tunes") are presented for the pythia8 event generator. These tunes use the NNPDF3.1 parton distribution functions (PDFs) at leading (LO), next-to-leading (NLO), or next-to-next-to-leading (NNLO) orders in perturbative quantum chromodynamics, and the strong coupling evolution at LO or NLO. Measurements of charged-particle multiplicity and transverse momentum densities at various hadron collision energies are fit simultaneously to determine the parameters of the tunes. Comparisons of the predictions of the new tunes are provided for observables sensitive to the event shapes at LEP, global underlying event, soft multiparton interactions, and double-parton scattering contributions. In addition, comparisons are made for observables measured in various specific processes, such as multijet, Drell-Yan, and top quark-antiquark pair production including jet substructure observables. The simulation of the underlying event provided by the new tunes is interfaced to a higher-order matrix-element calculation. For the first time, predictions from pythia8 obtained with tunes based on NLO or NNLO PDFs are shown to reliably describe minimum-bias and underlying-event data with a similar level of agreement to predictions from tunes using LO PDF sets.

Intrinsic human immunodeficiency virus type 1 resistance of hematopoietic stem cells despite coreceptor expression

Interactions of human immunodeficiency virus type 1 (HIV-1) with hematopoietic stem cells may define restrictions on immune reconstitution following effective antiretroviral therapy and affect stem cell gene therapy strategies for AIDS. In the present study, we demonstrated mRNA and cell surface expression of HIV-1 receptors CD4 and the chemokine receptors CCR-5 and CXCR-4 in fractionated cells representing multiple stages of hematopoietic development. Chemokine receptor function was documented in subsets of cells by calcium flux in response to a cognate ligand. Productive infection by HIV-1 via these receptors was observed with the notable exception of stem cells, in which case the presence of CD4, CXCR-4, and CCR-5, as documented by single-cell analysis for expression and function, was insufficient for infection. Neither productive infection, transgene expression, nor virus entry was detectable following exposure of stem cells to either wild-type HIV-1 or lentivirus constructs pseudotyped in HIV-1 envelopes of macrophage-tropic, T-cell-tropic, or dualtropic specificity. Successful entry into stem cells of a vesicular stomatitis virus G protein-pseudotyped HIV-1 construct demonstrated that the resistance to HIV-1 was mediated at the level of virus-cell membrane fusion and entry. These data define the hematopoietic stem cell as a sanctuary cell which is resistant to HIV-1 infection by a mechanism independent of receptor and coreceptor expression that suggests a novel means of cellular protection from HIV-1.

Sensitive enzyme-linked immunosorbent assay for detection of Clostridium botulinum neurotoxins A, B, and E using signal amplification via enzyme-linked coagulation assay

A new immunoassay amplification method has been applied to the measurement of toxins A, B, and E from Clostridium botulinum. The technique is a modified enzyme-linked immunosorbent assay (ELISA) which relies on the detection of sandwich complexes on microtiter plates by a solid-phase coagulation assay known as ELCA, or enzyme-linked coagulation assay. In the method, a coagulation activating enzyme (RVV-XA) isolated from the venom of Russell's viper is conjugated to affinity-purified horse antibodies specific for toxin type A, B, or E. Plates are coated with affinity-purified antibodies, and standard captag (capture-tag) protocols using labeled antibody are employed to bind the toxin from solution. Complexes are detected by adding a modified plasma substrate which contains all the coagulation factors mixed with alkaline phosphatase-labeled fibrinogen and solid-phase fibrinogen; deposition of solid-phase, enzyme-labeled fibrin on the solid phase is then a reflection of formation of toxin-RVV-XA-antibody complexes on the solid phase. Because of the ability to detect RVV-XA by this coagulation assay at concentrations < 0.1 pg/ml, it was possible to measure C. botulinum toxins A, B, and E at mouse bioassay levels (< 10 pg/ml, or < 0.07 pM) for both purified neurotoxin and crude culture filtrates obtained from strains known to produce appropriate single toxins. ELISA-ELCA should be applicable to measurement of toxins in most of the materials (contaminated food, blood, and excreta) for which the comparably sensitive mouse bioassay is currently employed. This method has the potential of broad application to the measurement of low concentrations of any antigen for which appropriate immunochemical reagents are available, in a color test format.

Preclinical and clinical activity of sunitinib in patients with cisplatin-refractory or multiply relapsed germ cell tumors: a Canadian Urologic Oncology Group/German Testicular Cancer Study Group cooperative study

BACKGROUND

The objective of the study was to investigate the activity of sunitinib in a cell line model and subsequently in patients with cisplatin-refractory or multiply relapsed germ cell tumors (GCT).

METHODS

The effect of sunitinib on cell proliferation in cisplatin-sensitive and cisplatin-refractory GCT cell lines was evaluated after 48-h sunitinib exposure by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay, and IC(50) (concentration that causes 50% inhibition of growth) doses were determined. Sunitinib was subsequently administered at a dose of 50 mg/day for 4 weeks followed by a 2-week break to 33 patients using a Simon two-stage design.

RESULTS

Sunitinib demonstrated comparable dose-dependent growth inhibition in cisplatin-sensitive and cisplatin-resistant cell lines, with IC(50) between 3.0 and 3.8 μM. Patient characteristics were as follows: median of 2 (1-6) cisplatin-containing regimens; high-dose chemotherapy 67%; late relapse 33%; and cisplatin refractory or absolute cisplatin refractory 54%. Toxic effects included fatigue (39%), anorexia (21%), diarrhea (27%), mucositis (45%), nausea (33%), hand-foot syndrome (12%), dyspepsia (27%), and skin rash (18%). No unexpected side-effects were observed. Thirty -two of 33 patients were assessable for response. Three confirmed partial responses (PRs) and one unconfirmed PR were seen for a total response rate of 13%. Median progression-free survival (PFS) was 2 months, with a 6-month PFS rate of 11%.

CONCLUSIONS

Sunitinib shows in vitro activity in cisplatin-resistant GCT cell lines. Modest clinical activity in heavily pretreated GCT patients was observed.