bluuebunny/crossref_metadata_2025 huggingface dataset:
The modified BODE index: validation with mortality in COPD
Authors: Cote C. G. , Pinto-Plata V. M. , Marin J. M. , Nekach H. , Dordelly L. J. , Celli B. R.
Published: June 2008

Peak oxygen uptake (V′O2) remains the gold standard measurement of exercise capacity and has been associated with survival. A modified BODE (body mass index, airflow obstruction, dyspnoea, exercise capacity) index replacing the 6-min walk distance (6MWD) withV′O2as % predicted (mBODE%) has been developed and found to have excellent correlation with the conventional BODE index.

The objectives of the present study were to compare the ability of the conventional BODE and the mBODE% to predict mortality in 444 patients with chronic obstructive pulmonary disease (COPD) followed for a mean±sdperiod of 71±34 months. Anthropometrics, spirometry, lung volumes, comorbidity, cardiopulmonary cyclo-ergometry test and 6MWD were determined at entry.

The mean BODE indices for the cohort were: BODE 4.1±2 and mBODE% 5.5±2. Both indices were significantly correlated with mortality. Logistic regression analysis with COPD survival as the dependent variable identified the BODE index, Charlson's and exercise capacity (in W) as variables associated with this outcome.

In conclusion, the conventional BODE index, which uses the 6-min walk distance, predicts mortality in chronic obstructive pulmonary disease as well as the modified index using peak oxygen uptake. The results support the use of the simpler index, which includes the 6-min walk distance in the comprehensive evaluation of patients with chronic obstructive pulmonary disease.
Relationship between metabolic and genomic diversity in sesame (Sesamum indicum L.)
Authors: Laurentin Hernán , Ratzinger Astrid , Karlovsky Petr
Published: June 2008

Background

Diversity estimates in cultivated plants provide a rationale for conservation strategies and support the selection of starting material for breeding programs. Diversity measures applied to crops usually have been limited to the assessment of genome polymorphism at the DNA level. Occasionally, selected morphological features are recorded and the content of key chemical constituents determined, but unbiased and comprehensive chemical phenotypes have not been included systematically in diversity surveys. Our objective in this study was to assess metabolic diversity in sesame by nontargeted metabolic profiling and elucidate the relationship between metabolic and genome diversity in this crop.

Results

Ten sesame accessions were selected that represent most of the genome diversity of sesame grown in India, Western Asia, Sudan and Venezuela based on previous AFLP studies. Ethanolic seed extracts were separated by HPLC, metabolites were ionized by positive and negative electrospray and ions were detected with an ion trap mass spectrometer in full-scan mode for m/z from 50 to 1000. Genome diversity was determined by Amplified Fragment Length Polymorphism (AFLP) using eight primer pair combinations. The relationship between biodiversity at the genome and at the metabolome levels was assessed by correlation analysis and multivariate statistics.

Conclusion

Patterns of diversity at the genomic and metabolic levels differed, indicating that selection played a significant role in the evolution of metabolic diversity in sesame. This result implies that when used for the selection of genotypes in breeding and conservation, diversity assessment based on neutral DNA markers should be complemented with metabolic profiles. We hypothesize that this applies to all crops with a long history of domestication that possess commercially relevant traits affected by chemical phenotypes.
Molecular cloning and expression analysis of the STAT1 gene from olive flounder, Paralichthys olivaceus
Authors: Park Eun-Mi , Kang Jung-Ha , Seo Jung Soo , Kim GunDo , Chung Jongkyeong , Choi Tae-Jin
Published: June 2008

Background

Signal transducer and activator of transcription 1 (STAT1) is a critical component of interferon (IFN)-alpha/beta and IFN-gamma signaling. Although seven isoforms of STAT proteins have been reported from mammals, limited information is available for the STAT genes in fish. We isolated complementary DNA with high similarity to mammalian STAT1 from the olive flounder, Paralichthys olivaceus.

Results

A DNA fragment containing the conserved SH2 domain was amplified by RT-PCR using degenerate primers designed based on the highly conserved sequences in the SH2 domains of the zebrafish and mammalian STAT1. The complete cDNA sequence was obtained by 5' and 3' RACE. The flounder STAT1 transcript consisted of 2,909 bp that encoded a polypeptide of 749 amino acids. The overall similarity between flounder STAT1 and other STATs was very high, with the highest amino acid sequence identity to snakehead (89%). Phylogenetic analyses reveal that flounder STAT1 is in the same monophyletic group with snakehead STAT1. Quantitative real time RT-PCR and in situ hybridization revealed that STAT1 was expressed in almost all examined organs and tissues, with high expression in gill, spleen, kidney, and heart. The accumulation of STAT1 mRNA in different developmental stages, as determined by real time RT-PCR, increased with development.

Conclusion

Recent cloning of various cytokine genes and the STAT1 gene of olive flounder here suggest that fish also use the highly specialized JAK-STAT pathway for cytokine signaling. Identification of other STAT genes will elucidate in detail the signal transduction system in this fish.
Multiplex cytokine profile from dengue patients: MIP-1beta and IFN-gamma as predictive factors for severity
Authors: Bozza Fernando A , Cruz Oswaldo G , Zagne Sonia MO , Azeredo Elzinandes L , Nogueira Rita MR , Assis Edson F , Bozza Patricia T , Kubelka Claire F
Published: June 2008

Background

Dengue virus pathogenesis is not yet fully understood and the identification of patients at high risk for developing severe disease forms is still a great challenge in dengue patient care. During the present study, we evaluated prospectively the potential of cytokines present in plasma from patients with dengue in stratifying disease severity.

Methods

Seventeen-cytokine multiplex fluorescent microbead immunoassay was used for the simultaneous detection in 59 dengue patients. GLM models using bimodal or Gaussian family were determined in order to associate cytokines with clinical manifestations and laboratory diagnosis.

Results

IL-1β, IFN-γ, IL-4, IL-6, IL-13, IL-7 and GM-CSF were significantly increased in patients with severe clinical manifestations (severe dengue) when compared to mild disease forms (mild dengue). In contrast, increased MIP-1β levels were observed in patients with mild dengue. MIP-1β was also associated with CD56+NK cell circulating rates. IL-1β, IL-8, TNF-α and MCP-1 were associated with marked thrombocytopenia. Increased MCP-1 and GM-CSF levels correlated with hypotension. Moreover, MIP-1β and IFN-γ were independently associated with both dengue severity and disease outcome.

Conclusion

Our data demonstrated that the use of a multiple cytokine assay platform was suitable for identifying distinct cytokine profiles associated with the dengue clinical manifestations and severity. MIP-β is indicated for the first time as a good prognostic marker in contrast to IFN-γ that was associated with disease severity.
Characterization of early and terminal complement proteins associated with polymorphonuclear leukocytes in vitro and in vivo after spinal cord injury
Authors: Nguyen Hal X , Galvan Manuel D , Anderson Aileen J
Published: June 2008

Background

The complement system has been suggested to affect injury or disease of the central nervous system (CNS) by regulating numerous physiological events and pathways. The activation of complement following traumatic CNS injury can also result in the formation and deposition of C5b-9 membrane attack complex (C5b-9/MAC), causing cell lysis or sublytic effects on vital CNS cells. Although complement proteins derived from serum/blood-brain barrier breakdown can contribute to injury or disease, infiltrating immune cells may represent an important local source of complement after injury. As the first immune cells to infiltrate the CNS within hours post-injury, polymorphonuclear leukocytes (PMNs) may affect injury through mechanisms associated with complement-mediated events. However, the expression/association of both early and terminal complement proteins by PMNs has not been fully characterized in vitro, and has not observed previously in vivo after traumatic spinal cord injury (SCI).

Method

We investigated the expression of complement mRNAs using rt-PCR and the presence of complement proteins associated with PMNs using immunofluroescence and quantitative flow cytometry.

Results

Stimulated or unstimulated PMNs expressed mRNAs encoding for C1q, C3, and C4, but not C5, C6, C7 or C9 in culture. Complement protein C1q or C3 was also detected in less than 30% of cultured PMNs. In contrast, over 70% of PMNs that infiltrated the injured spinal cord were associated with C1q, C3, C7 and C5b-9/MAC 3 days post-SCI. The localization/association of C7 or C5b-9/MAC with infiltrating PMNs in the injured spinal cord suggests the incorporation or internalization of C7 or C5b-9/MAC bound cellular debris by infiltrating PMNs because C7 and C5b-9/MAC were mostly localized to granular vesicles within PMNs at the spinal cord epicenter region. Furthermore, PMN presence in the injured spinal cord was observed for many weeks post-SCI, suggesting that this infiltrating cell population could chronically affect complement-mediated events and SCI pathogenesis after trauma.

Conclusion

Data presented here provide the first characterization of early and terminal complement proteins associated with PMNs in vitro and in vivo after SCI. Data also suggest a role for PMNs in the local internalization or deliverance of complement and complement activation in the post-SCI environment.
The effects of protein interactions, gene essentiality and regulatory regions on expression variation
Authors: Zhou Linqi , Ma Xiaotu , Sun Fengzhu
Published: June 2008

Background

Identifying factors affecting gene expression variation is a challenging problem in genetics. Previous studies have shown that the presence of TATA box, the number of cis-regulatory elements, gene essentiality, and protein interactions significantly affect gene expression variation. Nonetheless, the need to obtain a more complete understanding of such factors and how their interactions influence gene expression variation remains a challenge. The growth rates of yeast cells under several DNA-damaging conditions have been studied and a gene's toxicity degree is defined as the number of such conditions that the growth rate of the yeast deletion strain is significantly affected. Since toxicity degree reflects a gene's importance to cell survival under DNA-damaging conditions, we expect that it is negatively associated with gene expression variation. Mutations in both cis-regulatory elements and transcription factors (TF) regulating a gene affect the gene's expression and thus we study the relationship between gene expression variation and the number of TFs regulating a gene. Most importantly we study how these factors interact with each other influencing gene expression variation.

Results

Using yeast as a model system, we evaluated the effects of four separate factors and their interactions on gene expression variation: protein interaction degree, toxicity degree, number of TFs, and the presence of TATA box. Results showed that 1) gene expression variation is negatively correlated with the protein interaction degree in the protein interaction network, 2) essential genes tend to have less expression variation than non-essential genes and gene expression variation decreases with toxicity degree, and 3) the number of TFs regulating a gene is the most important factor influencing gene expression variation (R2 = 8–14%). In addition, the number of TFs regulating a gene was found to be an important factor influencing gene expression variation for both TATA-containing and non-TATA-containing genes, but with different association strength. Moreover, gene expression variation was significantly negatively correlated with toxicity degree only for TATA-containing genes.

Conclusion

The finding that distinct mechanisms may influence gene expression variation in TATA-containing and non-TATA-containing genes, provides new insights into the mechanisms that underlie the evolution of gene expression.
Induction of arthritis by high mobility group box chromosomal protein 1 is independent of tumour necrosis factor signalling
Authors: Pullerits Rille , Jonsson Ing-Marie , Kollias George , Tarkowski Andrej
Published: June 2008

Introduction

TNFα and high mobility group box chromosomal protein 1 (HMGB1) are two potent proinflammatory cytokines implicated as important mediators of arthritis. Increased levels of these cytokines are found in the joints of rheumatoid arthritis patients, and the cytokines trigger arthritis when applied into the joints of naïve mice. HMGB1 is actively released from immune cells in response to TNFα; once released, HMGB1 in turn induces production of several proinflammatory cytokines – including IL-6 and TNFα – by macrophages. Whether HMGB1-induced arthritis is mediated via the TNFα pathway, however, is unknown. The purpose of the present study was to investigate whether the arthritis-inducing effect of HMGB1 is dependent on TNFα expression in vivo and to assess whether TNFα deficiency affects a proinflammatory cytokine response to HMGB1 in vitro.

Methods

TNFα knockout mice and backcrossed control animals on a C57Bl6 background were injected intraarticularly with 5 μg HMGB1. Joints were dissected 3 days after intraarticular injection and were evaluated histologically by scoring the frequency and severity of arthritis. For in vitro studies, mouse spleen cultures from TNFα knockout mice and from control mice were incubated with different doses of HMGB1, and cell culture supernatants were collected at different time points for analysis of IL-6.

Results

Intraarticular injection of HMGB1 into healthy mouse joints resulted in an overall frequency of 32% to 39% arthritic animals. No significant differences were found with respect to the severity and incidence of synovitis between mice deficient for TNFα (seven out of 18 mice with arthritis) in comparison with control TNFα+/+ animals (six out of 19). No significant differences were detected between spleen cells from TNFα+/+ mice versus TNFα-/- mice regarding IL-6 production upon stimulation with highly purified HMGB1 after 24 hours and 48 hours. Upon stimulation with a suboptimal dose of recombinant HMGB1, however, the splenocytes from TNFα+/+ animals released significantly more IL-6 than cells from the knockout mice (602 ± 112 pg/ml and 304 ± 50 pg/ml, respectively; P < 0.05).

Conclusion

Our data show that HMGB1-triggered joint inflammation is not mediated via the TNF pathway. Combined with our previous study, we suggest that HMGB1-triggered arthritis is probably mediated through IL-1 activation.
Adipose-immune interactions during obesity and caloric restriction: reciprocal mechanisms regulating immunity and health span
Authors: Dixit Vishwa Deep
Published: June 2008

Increasing evidence suggests a tight coupling of metabolic and immune systems. This cross-talk mediated by neuroendocrine peptides as well as numerous cytokines and chemokines is believed to be responsible for integrating energy balance to immune function. These neuroendocrine-immune interactions are heightened during the state of chronic positive energy balance, as seen during obesity, and negative energy balance caused by caloric restriction (CR). Emerging evidence suggests that obesity may be associated with an immunodeficient state and chronic inflammation, which contribute to an increased risk of premature death. The direct interactions between expanded leukocyte populations within the adipose tissue during obesity and an increased number of adipocytes within an aging lymphoid microenvironment may constitute an important adaptive or pathological response as a result of change in energy balance. In stark contrast to obesity, CR causes negative energy balance and robustly prolongs a healthy lifespan in all of the species studied to date. Therefore, the endogenous neuroendocrine-metabolic sensors elevated or suppressed as a result of changes in energy balance may offer an important mechanism in understanding the antiaging and potential immune-enhancing nature of CR. Ghrelin, one such sensor of negative energy balance, is reduced during obesity and increased by CR. Ghrelin also regulates immune function by reducing proinflammatory cytokines and promotes thymopoiesis during aging and thus, may be a new CR mimetic target. The identification of immune effects and molecular pathways used by such orexigenic metabolic factors could offer potentially novel approaches to enhance immunity and increase healthy lifespan.
Increased Cdx protein dose effects upon axial patterning in transgenic lines of mice
Authors: Gaunt Stephen J. , Drage Deborah , Trubshaw Richard C.
Published: June 2008

To investigate the link between Cdx protein concentration and axial patterning in embryos, we made lines of mice OE1, OE2 and OE4 that overexpress each of the Cdx genes Cdx1, Cdx2 and Cdx4,respectively. The lines carry Cdx transgenes under the transcriptional control of their own promoter/enhancer elements. Transgenic embryos show Cdx transcription at 8.5 to 8.7 days within normal spatial domains for Cdx expression (primitive streak/tailbud), yet, overall, they contain elevated levels of Cdx proteins. Increased doses of Cdx proteins result in homeotic shifts in vertebral types along most of the vertebral column, with transformations being most obvious within the cervical region. Most of the shifts are anterior-to-posterior transformations and the anterior limits of these are commonly skull/vertebra 1 (v1) for OE1, v1/v2 for OE2 and v7 for OE4. OE embryos display anterior shifts in the expression of a Hoxa7/lacZ reporter within neural, paraxial and lateral plate mesoderm tissues. Hoxa7/lacZ expression commences at the normal time in OE1 and OE4 embryos. OE2 embryos display a forward shift in the gradient of Cdx2 protein along the axis, suggesting that a Cdx morphogen gradient model could account, at least in part, for the homeotic shifts in vertebral types. OE mice display additional defects: forelimb deficiencies in OE1, multiple tail axes, vertebral mis-alignments and axial truncations in OE2.
Dual hindlimb control elements in theTbx4gene and region-specific control of bone size in vertebrate limbs
Authors: Menke Douglas B. , Guenther Catherine , Kingsley David M.
Published: June 2008

The Tbx4 transcription factor is crucial for normal hindlimb and vascular development, yet little is known about how its highly conserved expression patterns are generated. We have used comparative genomics and functional scanning in transgenic mice to identify a dispersed group of enhancers controlling Tbx4 expression in different tissues. Two independent enhancers control hindlimb expression, one located upstream and one downstream of the Tbx4 coding exons. These two enhancers, hindlimb enhancer A and hindlimb enhancer B (HLEA and HLEB), differ in their primary sequence, in their precise patterns of activity within the hindlimb, and in their degree of sequence conservation across animals. HLEB is highly conserved from fish to mammals. Although Tbx4 expression and hindlimb development occur at different axial levels in fish and mammals, HLEB cloned from either fish or mouse is capable of driving expression at the appropriate position of hindlimb development in mouse embryos. HLEA is highly conserved only in mammals. Deletion of HLEA from the endogenous mouse locus reduces expression of Tbx4 in the hindlimb during embryogenesis, bypasses the embryonic lethality of Tbx4-null mutations, and produces viable, fertile mice with characteristic changes in the size of bones in the hindlimb but not the forelimb. We speculate that dual hindlimb enhancers provide a flexible genomic mechanism for altering the strength and location of Tbx4 expression during normal development, making it possible to separately modify the size of forelimb and hindlimb bones during vertebrate evolution.
The pro-domain of the zebrafish Nodal-related protein Cyclops regulates its signaling activities
Authors: Tian Jing , Andrée Birgit , Jones C. Michael , Sampath Karuna
Published: June 2008

Nodal proteins are secreted signaling factors of the transforming growth factor β (TGFβ) family with essential roles in embryonic development in vertebrates. Mutations affecting the Nodal factors have severe consequences in mammals and fish. Furthermore, increased Nodal levels have been associated with melanoma tumor progression. Like other TGFβ-related proteins, Nodal factors consist of a pro-domain and a mature domain. The pro-domain of mouse Nodal protein stabilizes its precursor. However, the mechanisms by which the pro-domains exert their activities are unknown. Here, we characterize the zebrafish Nodal-related factor Cyclops (Cyc) and find unexpected functions for the pro-domain in regulating Cyc activity. We identified a lysosome-targeting region in the Cyc pro-domain that destabilizes the precursor and restricts Cyc activity, revealing the molecular basis for the short-range signaling activities of Cyc. We show that both the pro- and mature-domains of Cyc regulate its stability. We also characterize a mutation in the pro-domain of human NODAL (hNODAL) that underlies congenital heterotaxia. Heterologous expression of mutant hNODAL increases expression of Nodal-response genes. Our studies reveal unexpected roles for the pro-domain of the Nodal factors and provide a possible mechanism for familial heterotaxia.
Mesp2 and Tbx6 cooperatively create periodic patterns coupled with the clock machinery during mouse somitogenesis
Authors: Oginuma Masayuki , Niwa Yasutaka , Chapman Deborah L. , Saga Yumiko
Published: June 2008

The metameric structures in vertebrates are based on the periodicity of the somites that are formed one by one from the anterior end of the presomitic mesoderm (PSM). The timing and spacing of somitogenesis are regulated by the segmentation clock, which is characterized by the oscillation of several signaling pathways in mice. The temporal information needs to be translated into a spatial pattern in the so-called determination front, at which cells become responsive to the clock signal. The transcription factor Mesp2 plays a crucial role in this process, regulating segmental border formation and rostro-caudal patterning. However, the mechanisms regulating the spatially restricted and periodic expression of Mesp2 have remained elusive. Using high-resolution fluorescent in situ hybridization in conjunction with immunohistochemical analyses, we have found a clear link between Mesp2 transcription and the periodic waves of Notch activity. We also find that Mesp2 transcription is spatially defined by Tbx6: Mesp2 transcription and Tbx6 protein initially share an identical anterior border in the PSM, but once translated, Mesp2 protein leads to the suppression of Tbx6 protein expression post-translationally via rapid degradation mediated by the ubiquitin-proteasome pathway. This reciprocal regulation is the spatial mechanism that successively defines the position of the next anterior border of Mesp2. We further show that FGF signaling provides a spatial cue to position the expression domain of Mesp2. Taken together, we conclude that Mesp2 is the final output signal by which the temporal information from the segmentation clock is translated into segmental patterning during mouse somitogenesis.
Sdf1/Cxcr4 signaling controls the dorsal migration of endodermal cells during zebrafish gastrulation
Authors: Mizoguchi Takamasa , Verkade Heather , Heath Joan K. , Kuroiwa Atsushi , Kikuchi Yutaka
Published: June 2008

During vertebrate gastrulation, both mesodermal and endodermal cells internalize through the blastopore beneath the ectoderm. In zebrafish, the internalized mesodermal cells move towards the dorsal side of the gastrula and, at the same time, they extend anteriorly by convergence and extension(C&E) movements. Endodermal cells showing characteristic filopodia then migrate into the inner layer within the hypoblast next to the yolk syncytial layer (YSL). However, little is known about how the movement of endodermal cells is regulated during gastrulation. Here we show that sdf1a- and sdf1b-expressing mesodermal cells control the movements of the cxcr4a-expressing endodermal cells. The directional migration of endodermal cells during gastrulation is inhibited by knockdown of either cxcr4a or sdf1a/sdf1b (sdf1). We also show that misexpressed Sdf1 acts as a chemoattractant for cxcr4a-expressing endodermal cells. We further found, using the endoderm-specific transgenic line Tg(sox17:EGFP), that Sdf1/Cxcr4 signaling regulates both the formation and orientation of filopodial processes in endodermal cells. Moreover, the accumulation of phosphoinositide 3,4,5-trisphosphate (PIP3), which is known to occur at the leading edge of migrating cells, is not observed at the filopodia of endodermal cells. Based on our results, we propose that sdf1-expressing mesodermal cells, which overlie the endodermal layer, guide the cxcr4a-expressing endodermal cells to the dorsal side of the embryo during gastrulation, possibly through a PIP3-independent pathway.
Hes genes and neurogenin regulate non-neural versus neural fate specification in the dorsal telencephalic midline
Authors: Imayoshi Itaru , Shimogori Tomomi , Ohtsuka Toshiyuki , Kageyama Ryoichiro
Published: June 2008

The choroid plexus in the brain is unique because it is a non-neural secretory tissue. It secretes the cerebrospinal fluid and functions as a blood-brain barrier, but the precise mechanism of specification of this non-neural tissue has not yet been determined. Using mouse embryos and lineage-tracing analysis, we found that the prospective choroid plexus region initially gives rise to Cajal-Retzius cells, specialized neurons that guide neuronal migration. Inactivation of the bHLH repressor genes Hes1,Hes3 and Hes5 upregulated expression of the proneural gene neurogenin 2 (Ngn2) and prematurely depleted Bmp-expressing progenitor cells, leading to enhanced formation of Cajal-Retzius cells and complete loss of choroid plexus epithelial cells. Overexpression of Ngn2 had similar effects. These data indicate that Hes genes promote specification of the fate of choroid plexus epithelial cells rather than the fate of Cajal-Retzius cells by antagonizing Ngn2 in the dorsal telencephalic midline region, and thus this study has identified a novel role for bHLH genes in the process of deciding which cells will have a non-neural versus a neural fate.
Temporal requirements of the fragile X mental retardation protein in the regulation of synaptic structure
Authors: Gatto Cheryl L. , Broadie Kendal
Published: June 2008

Fragile X syndrome (FraX), caused by the loss-of-function of one gene(FMR1), is the most common inherited form of both mental retardation and autism spectrum disorders. The FMR1 product (FMRP) is an mRNA-binding translation regulator that mediates activity-dependent control of synaptic structure and function. To develop any FraX intervention strategy, it is essential to define when and where FMRP loss causes the manifestation of synaptic defects, and whether the reintroduction of FMRP can restore normal synapse properties. In the Drosophila FraX model, dFMRP loss causes neuromuscular junction (NMJ) synapse over-elaboration (overgrowth,overbranching, excess synaptic boutons), accumulation of development-arrested satellite boutons, and altered neurotransmission. We used the Gene-Switch method to conditionally drive dFMRP expression to define the spatiotemporal requirements in synaptic mechanisms. Constitutive induction of targeted neuronal dFMRP at wild-type levels rescues all synaptic architectural defects in Drosophila Fmr1 (dfmr1)-null mutants, demonstrating a presynaptic requirement for synapse structuring. By contrast, presynaptic dFMRP expression does not ameliorate functional neurotransmission defects,indicating a postsynaptic dFMRP requirement. Strikingly, targeted early induction of dFMRP effects nearly complete rescue of synaptic structure defects, showing a primarily early-development role. In addition, acute dFMRP expression at maturity partially alleviates dfmr1-null defects,although rescue is not as complete as either early or constitutive dFMRP expression, showing a modest capacity for late-stage structural plasticity. We conclude that dFMRP predominantly acts early in synaptogenesis to modulate architecture, but that late dFMRP introduction at maturity can weakly compensate for early absence of dFMRP function.
The diagnostic value of serum and urinary NT-proBNP for heart failure
Authors: Michielsen Etienne C H J , Bakker Jaap A , Kimmenade Roland R J Van , Pinto Yigal M , Dieijen-Visser Marja P Van
Published: June 2008

Background

Serum B-type natriuretic peptide (BNP) and the amino-terminal cleavage product of the prohormone (NT-proBNP) have been shown to be valuable parameters for the diagnosis of heart failure (HF) in the general population. Urinary BNP and NT-proBNP have also been suggested for diagnosis of HF. The present study investigated the diagnostic value of both serum and urinary NT-proBNP in selected groups of controls and patients diagnosed with HF.

Methods

Creatinine clearance and serum and urinary NT-proBNP were measured in 76 controls and in 47 patients diagnosed with HF (NYHA III and IV). Echocardiography was used to exclude cardiac dysfunction in the control population by the combined normality of left ventricular ejection fraction (LVEF), E/A ratio (echocardiographic early [E] and late, or atrial [A] phases of ventricular filling), deceleration time and LV mass index. All patients diagnosed with HF had LVEF <40%.

Results

NT-proBNP measurements in urine samples are subject to high variability. Receiver-operating characteristic area under the curve (AUC) for serum, urinary NT-proBNP and their products were 0.94, 0.72 and 0.93, respectively. Correction of urinary NT-proBNP for urinary creatinine content improved the AUC from 0.72 to 0.80. Negative predictive values for ruling out HF were 0.94, 0.67 and 0.89, respectively. Linear regression analysis revealed that creatinine clearance was more important in determining serum NT-proBNP concentrations than age.

Conclusions

Serum NT-proBNP is the best parameter to rule out HF. The product of the serum and urinary concentrations has equal value. Urinary NT-proBNP alone performs rather poorly. Renal function influences NT-proBNP concentrations more than age in this selected population.
Measurement of urinary free cortisol by tandem mass spectrometry and comparison with results obtained by gas chromatography-mass spectrometry and two commercial immunoassays
Authors: Wood Lisa , Ducroq David H , Fraser Helen L , Gillingwater Scott , Evans Carol , Pickett Alan J , Rees Derek W , John Rhys , Turkes Atilla
Published: June 2008

Background

Determination of urinary free cortisol (UFC) is an important adjunct for the assessment of adrenal function. In this study, we have analysed cortisol concentrations in urine samples by gas chromatography-mass spectrometry (GC-MS), liquid chromatography-tandem mass spectrometry (LC-MS/MS) and two immunoassays. The results were compared with GC-MS. The interference of cortisol ring-A metabolites in immunoassays was also assessed.

Methods

The GC-MS technique involved solvent extraction, LH-20 clean-up and derivatization. Only solid-phase extraction procedure was used for LC-MS/MS. The samples were analysed in positive electro-spray ionization mode, monitoring the transitions for cortisol and deuterated-cortisol at m/z 363.3 > 121.2 and m/z 365.3 > 122.2, respectively. Immunoassays were performed according to the manufacturer's instructions.

Results

When compared with GC-MS results both immunoassays (Coat-A-Count; approximately 1.9-fold, Centaur; approximately 1.6-fold) overestimated UFC concentrations. Cortisol ring-A dihydro- and tetrahydrometabolites contribute significantly to this overestimation. There was no interference by these metabolites in either GC-MS or LC-MS/MS methods. The sensitivity of the LC-MS/MS procedure was 2 nmol/L and the intra- and inter-assay variations were <5% in each quality-control sample. The comparison of the UFC results achieved by assaying the study samples with GC-MS and LC-MS/MS indicated that the agreement between the two methods was excellent (LC-MS/MS = 1.0036GC-MS – 0.0841; r 2 = 0.9937).

Conclusions

The interference of cortisol ring-A metabolites in immunoassays contribute to overestimation of UFC concentrations. The LC-MS/MS procedure had the sensitivity, specificity, linearity, precision and accuracy for the determination of UFC concentrations. The method is suitable for routine use provided that method-dependant reference values are established.
The association of advanced glycation end-products with glutathione status
Authors: Şahin Emel , Göçmen Ayşe Yeşim , Koçak Hüseyin , Tuncer Murat , Gümüşlü Saadet
Published: June 2008

Background

The aim of this study was to investigate oxidative stress with regard to the concentrations of advanced oxidation protein products (AOPP), advanced glycation end-products (AGEs), pentosidine, glycated albumin, reduced glutathione (GSH) and oxidized glutathione (GSSG), glutathione redox ratios and thiobarbituric acid-reactive substances (TBARS) in non-diabetic patients undergoing continuous ambulatory peritoneal dialysis (CAPD).

Methods

The study group consisted of 52 non-diabetic CAPD patients and 34 healthy controls. AOPP, AGEs, pentosidine and glycated albumin were measured in plasma, whereas GSH, GSSG and TBARS concentrations were measured in erythrocytes of both patients and controls.

Results

All parameters were found to be significantly increased, except the glutathione redox ratio, which was found to be decreased in patients undergoing CAPD. Multiple regression analysis showed that AGEs were the only independent predictor of glutathione redox ratio, whereas AGEs, glycated albumin and TBARS were each found to be independent predictors of albumin concentration.

Conclusion

Our results support the hypothesis that oxidative stress and AOPPs/AGEs constitute important risk factors in CAPD patients. The negative relationship between albumin and both AGEs and TBARS suggests that the decrease in albumin may contribute to the increased advanced glycation and lipid peroxidation. The negative relationship between glutathione redox ratio and AGEs suggests that late products of glycation play an important role in the development of oxidative stress observed in patients undergoing peritoneal dialysis treatment.
Detection of citrullinated proteins in synovial fluids derived from patients with rheumatoid arthritis by proteomics-based analysis
Authors: Tabushi Yoko , Nakanishi Toyofumi , Takeuchi Tohru , Nakajima Mikio , Ueda Kazuhito , Kotani Takuya , Makino Shigeki , Shimizu Akira , Hanafusa Toshiaki , Takubo Takayuki
Published: June 2008

Background

Rheumatoid arthritis (RA) is the most common inflammatory joint disease. The aetiology of RA remains unknown, but autoimmune responses are considered to play an important role in the disease pathophysiology. Currently available data suggests that the process of diagnosing RA may benefit from testing for anticyclic citrullinated peptides. Identification of the presence of citrullinated proteins in rheumatoid synovial fluids is important for the elucidation of the aetiology of RA as well as in the differential diagnosis of rheumatic-related diseases.

Methods

A proteomics-based approach using electrophoresis/mass spectrometry was applied to identify the citrullinated proteins in synovial fluids from patients with RA. Synovial fluids from patients with RA were subjected to sodium dodecyl sulfate–polyacrylamide gel electrophoresis and Western blot analysis to detect the citrullinated proteins. Identification bands were then subjected to mass spectrometry.

Results

Three proteins – citrullinated fibrinogen, citrullinated fibronectin and citrullinated vimentin – in synovial fluids from RA patients were identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry.

Conclusions

Proteomics-based analysis can be used to detect citrullinated proteins in synovial fluids from RA patients.
Multiple molecular forms of circulating cardiac troponin: analytical and clinical significance
Authors: Gaze David C , Collinson Paul O
Published: June 2008

Cardiac troponin T (cTnT) and I (cTnI) are highly specific and sensitive biomarkers of myocardial cell damage and are now accepted as the ‘gold standard’ diagnostic test for acute coronary syndrome and supersede the classical muscle enzyme biomarkers. While the understanding of the development and structure of the troponins has advanced, detailed biochemistry of the troponin molecules is complex and poorly understood. Many post-translational molecular forms of troponin are known to exist. The diversity of these circulating forms may have a clinical impact and the notion of a disease-specific troponin protein signature has been suggested. However, the effects of these multiple forms on commercial assay performance and their impact clinically are currently unknown and should be the focus of future research and assay design.
Central pontine myelinolysis complicating treatment of the hyperglycaemic hyperosmolar state
Authors: O'Malley Grainne , Moran Carla , Draman Mohd Shazlie , King Tom , Smith Diarmuid , Thompson Chris J , Agha Amar
Published: June 2008

Central pontine myelinolysis (CPM) is well recognized to occur in a variety of clinical settings, but particularly following rapid correction of severe hyponatraemia. The development of CPM as a result of rapid shifts in plasma osmolality during the treatment of the hyperglycaemic hyperosmolar state (HHS) has hitherto been described in only one case. We report a second case in which this complication occurred in association with treatment of the HHS.

The patient was a 49-year-old woman who presented to another hospital with drowsiness and a plasma glucose of 106 mmol/L. Her admission plasma sodium was 135 mmol/L. She received treatment with intravenous insulin and 0.9% normal saline, and there was a rapid drop in plasma glucose by 60 mmol/L within 6 h, which was associated with a rebound rise of plasma sodium to 159 mmol/L. Her plasma glucose and sodium were later stabilized. When the patient was transferred to our hospital a few days later, she was noted to have flaccid quadraparesis and pseudobulbar palsy. A magnetic resonance imaging scan revealed a pontine lesion consistent with CPM. She made a gradual recovery over several months with intensive rehabilitation and eventually returned to near normal functional capacity. This is the second case report in the literature of CPM complicating the management of HHS and highlights the importance of the judicious and measured correction of hyperglycaemia and the appropriate management of fluid replacement and electrolyte balance when treating this condition.
Can plasma ammonia be measured in patients with acute liver disease?
Authors: Herrera Daniel Juan , Moore Steven , Heap Sarah , Preece Mary Anne , Griffiths Paul
Published: June 2008

Background

Plasma ammonia (PA) measurement is of key importance in the diagnosis and monitoring of some inherited metabolic disorders and to monitor subsequent treatment of hyperammonaemia.

Methods

Over a six-month period, patients' ammonia concentrations were measured in parallel, using an enzymatic–UV kit (Infinity Ammonia Liquid Stable Reagent, Thermo Electron Corporation, Australia) on an Olympus AU640 analyser (Olympus UK Ltd, Hertfordshire) and on our current dry chemistry system (Vitros 250, Ortho Clinical Diagnostic). Alanine amino transferase (ALT) was added to a human plasma sample to investigate its effect on the assessment of ammonia concentration.

Results

Both methods correlated well (InfinityTM kit = 1.12 × Vitros 250 + 39, R2 = 0.95, n = 105). However, clinically important discrepancies ranging from 100 to 380 μmol/L were found in patients with acute liver failure. Ammonia concentration measured with the enzymatic Infinity™ kit increased by 137 μmol/L when ALT was added up to 17,000 IU/L.

Conclusions

ALT produces a positive interference in the enzymatic Infinity™ kit which may affect interpretation and influence further clinical action. However, this positive interference due to ALT does not fully explain the discrepant results observed between the two methods in patients with acute liver failure.
Plasma insulin concentrations during a hyperinsulinaemic clamp: what do we measure?
Authors: Ackermans M T , Klieverik L P , Endert E , Sauerwein H P , Kalsbeek A , Fliers E
Published: June 2008

Background

The aim of this study is to compare the performance of three commonly used insulin assays with respect to the detection of exogenous human and porcine insulin added to human or rat plasma.

Methods

The DPC Immulite human insulin assay, the Mercodia rat insulin enzyme-linked immunosorbent assay and the Linco rat insulin radioimmunoassay were tested.

Results

The mean cross-reactivity of exogenous insulin ranged from 25% to 92%. The mean cross-reactivity of Actrapid in human plasma on the DPC Immulite was 56% and was independent of the endogenous insulin concentration.

Conclusions

The measurement of exogenous insulin varies according to the source of exogenous insulin, matrix and insulin assay.
Plasma lipoprotein β-amyloid in subjects with Alzheimer's disease or mild cognitive impairment
Authors: Mamo J C L , Jian L , James A P , Flicker L , Esselmann H , Wiltfang J
Published: June 2008

Background

Plasma amyloid β-peptide (Aβ) can compromise the blood-brain barrier, contributing to cerebrovascular alterations and amyloid angiopathy in Alzheimer's disease (AD). The objectives of this study were to investigate the distribution of lipoprotein-bound plasma-Aβ isoforms.

Methods

This involved a case-control study of subjects with AD or amnestic mild cognitive impairment (MCI) versus controls. Lipoprotein Aβ distribution was determined in fasted plasma. For assessment of chylomicron homeostasis in the postabsorptive state, subjects were bled 4 h after a low-fat meal. The main outcome measures were plasma lipoprotein Aβ isoform distribution and lipid homeostasis.

Results

We found the majority of plasma Aβ to be associated with triglyceride-rich lipoproteins (TRLs) encompassing chylomicrons, VLDL and IDL. For all lipoprotein groups, Aβ1–40 was the predominant isoform, accounting for approximately 50% of the total. Thereafter, equivalent amounts of the isoforms 1–42, 2–40, 1–38, 1–37 and 1–39 were found. Aβ1–37, Aβ1–38 and Aβ2–40 isoforms were significantly enriched within the TRL fraction of AD/MCI subjects and similar trends were observed for isoforms Aβ1–39, Aβ1–40 and Aβ1–42. Lipoprotein-Aβ was inversely associated with plasma total- and LDL cholesterol. AD/MCI subjects were not dyslipidaemic, however, there was evidence of accumulation of chylomicrons in the postabsorptive state.

Conclusions

Our data show that Aβ was found to be associated with plasma lipoproteins, especially those enriched with triglyceride. We find that Aβ may be increased in normolipidaemic AD subjects, commensurate with possible disturbances in postprandial lipoprotein homeostasis.
Copper deficiency: an unusual case of myelopathy with neuropathy
Authors: Bertfield Deborah L , Jumma Odai , Pitceathly Robert D S , Sussman Jon D
Published: June 2008

Copper deficiency is an unusual but potentially treatable cause of myelopathy. It should be considered in patients with poor nutrition or a history of gastrointestinal surgery. We report the case of an 82-year-old man who presented with sensory symptoms and gait ataxia.
The effect of plasmapheresis on the concentration of certain plasma proteins: a case identified by an inaccurate LDL-cholesterol estimation
Authors: Maguire O C , Mc Carthy D , Cunningham S K
Published: June 2008

A 35-year-old man was found to have a negative LDL-cholesterol concentration (−0.05 mmol/L) when estimated on a fasting plasma sample using the Friedewald equation. Plasma urea, electrolytes and liver function tests (LFTs) were normal except for a raised total bilirubin of 74 μmol/L. Haematological results showed both a low haemoglobin and fibrinogen concentration. It transpired that the patient had undergone daily plasmapheresis treatments on the previous four days; plasma had been exchanged with a 5% albumin solution. He had been diagnosed with Evan's syndrome previously (characterized by autoimmune haemolytic anaemia) and had been admitted with severe anaemia, which had proved unresponsive to conventional treatments. The concentration of most plasma substances is reduced by 50–60% after one standard plasmapheresis treatment, with the rate of return to steady state concentrations varying among analytes. The finding of a negative LDL-cholesterol concentration (arising primarily as a result of normal triglyceride concentrations) may reflect the more efficient removal of LDL and HDL lipoproteins during the plasmapheresis procedure (PP) than lipoproteins containing proportionally more triglycerides. Plasma lipids, total protein, immunoglobulins and transferrin had recovered to steady state concentrations by eight days post-plasmapheresis, whereas caeruloplasmin concentrations had not. This case report illustrates the difficulties of obtaining accurate information on the steady state concentrations of plasma analytes, in particular protein bound substances, when analysis is carried out on a sample from a patient that has recently undergone plasmapheresis. The normal plasma albumin in this situation did not flag the possibility of the sample being artefactually diluted.
Immunoglobulin G paraprotein cross-reactivity with immunoglobulin M measurement
Authors: Hawkins Robert C , Lee Lian-King
Published: June 2008

We report a case of IgG paraprotein cross-reactivity with IgM measurement in a patient with IgGκ multiple myeloma and associated IgA and IgM immune paresis. IgM measurements using a Beckman-Coulter Synchron LX IgM reagent initially gave unmeasurably low IgM concentrations (<0.3 g/L) but IgM quantitation using later batches of reagent gave IgM concentrations of 13–42 g/L. Immunofixation confirmed the continued presence of the IgGκ paraprotein band with suppression of IgA and IgM and analysis on the Behring BN2 and Beckman-Coulter Immage instruments showed IgM concentrations of <0.2 g/L. Immunofixation using the Synchron LX IgM reagent as antiserum confirmed binding of the Synchron LX IgM antiserum to the IgGκ paraprotein. This case highlights the importance of checking all unexpected immunoglobulin measurements with previous results and immunofixation findings to avoid mistakes.
Measurement of plasma lysophosphatidic acid concentration in healthy subjects: strong correlation with lysophospholipase D activity
Authors: Hosogaya Shigemi , Yatomi Yutaka , Nakamura Kazuhiro , Ohkawa Ryunosuke , Okubo Shigeo , Yokota Hiromitsu , Ohta Masato , Yamazaki Hirokazu , Koike Toru , Ozaki Yukio
Published: June 2008

Background

Lysophosphatidic acid (LPA) plays important roles in a variety of biological responses, especially in the area of vascular biology, and the determination of its plasma concentration is believed to be important. Several mechanisms are known to be involved in the metabolism of LPA.

Methods

To identify factors that may determine the plasma concentrations of this important bioactive lipid, we examined its concentrations using an enzymatic cycling assay and related parameters in 146 healthy subjects.

Results

The LPA concentration was significantly higher in women (mean ± SD, 0.103 ± 0.032 μmol/L; n = 47) than in men (0.077 ± 0.026 μmol/L; n = 99). A multiple regression analysis showed a strong positive correlation between the plasma LPA concentration and serum lysophospholipase D (lysoPLD) activity, while the LPA concentration was correlated with the plasma lysophosphatidylcholine (LPC) concentration only in men. Other lipid-related parameters were only slightly correlated or were not correlated with the LPA concentration.

Conclusions

Our findings suggested that conversion from LPC by lysoPLD might be the major route for LPA production in plasma.