bluuebunny/crossref_metadata_2025 huggingface dataset:
Phospholipase C-eta Enzymes as Putative Protein Kinase C and Ca2+ Signalling Components in Neuronal and Neuroendocrine Tissues
Authors: Stewart Alan J. , Morgan Kevin , Farquharson Colin , Millar Robert P.
Published: August 2007

Phosphoinositol-specific phospholipase C enzymes (PLCs) are central to inositol lipid signalling pathways, facilitating intracellular Ca2+ release and protein kinase C activation. A sixth class of phosphoinositol-specific PLC with a novel domain structure, PLC-eta (PLCη) has recently been discovered in mammals. Recent research, reviewed here, shows that this class consists of two enzymes, PLCη1 and PLCη2. Both enzymes hydrolyze phosphatidylinositol 4,5-bisphosphate and are more sensitive to Ca2+ than other PLC isozymes and are likely to mediate G-protein-coupled receptor (GPCR) signalling pathways. Both enzymes are expressed in neuron-enriched regions, being abundant in the brain. We demonstrate that they are also expressed in neuroendocrine cell lines. PLCη enzymes therefore represent novel proteins influencing intracellular Ca2+ dynamics and protein kinase C activation in the brain and neuroendocrine systems as putative mediation of GPCR regulation.
Platelet Activation by Oxidized Low Density Lipoprotein Is Mediated by Cd36 and Scavenger Receptor-A
Authors: Korporaal Suzanne J.A. , Van Eck Miranda , Adelmeijer Jelle , Ijsseldijk Martin , Out Ruud , Lisman Ton , Lenting Peter J. , Van Berkel Theo J.C. , Akkerman Jan-Willem N.
Published: August 2007

Objective—

The interaction of platelets with low density lipoprotein (LDL) contributes to the development of cardiovascular disease. Platelets are activated by native LDL (nLDL) through apoE Receptor 2′ (apoER2′)-mediated signaling to p38
MAPK
and by oxidized LDL (oxLDL) through lysophosphatidic acid (LPA) signaling to Rho A and Ca
2+
. Here we report a new mechanism for platelet activation by oxLDL.

Methods and Results—

Oxidation of nLDL increases p38
MAPK
activation through a mechanism that is (1) independent of LPA, and (2) unlike nLDL-signaling not desensitized by prolonged platelet-LDL contact or inhibited by receptor-associated protein or chondroitinase ABC. Antibodies against scavenger receptors CD36 and SR-A alone fail to block p38
MAPK
activation by oxLDL but combined blockade inhibits p38
MAPK
by >40% and platelet adhesion to fibrinogen under flow by >60%. Mouse platelets deficient in either CD36 or SR-A show normal p38
MAPK
activation by oxLDL but combined deficiency of CD36 and SR-A disrupts oxLDL-induced activation of p38
MAPK
by >70%.

Conclusion—

These findings reveal a novel platelet-activating pathway stimulated by oxLDL that is initiated by the combined action of CD36 and SR-A.
Involvement of Rho Kinase in Endothelial Barrier Maintenance
Authors: van Nieuw Amerongen G.P. , Beckers C.M.L. , Achekar I.D. , Zeeman S. , Musters R.J.P. , van Hinsbergh V.W.M.
Published: August 2007

Objective—Rho kinase mediates vascular leakage caused by many vasoactive agents including thrombin. Enhanced Rho kinase activity induces endothelial barrier dysfunction by a contractile mechanism via inactivation of Myosin Phosphatase (MP). Here, we investigated the contribution of basal Rho kinase activity to the regulation of endothelial barrier integrity.

Methods and Results—Using a phospho-specific antibody against the myosin phosphatase targeting subunit (Thr696−MYPT1) as a marker for Rho kinase activity, basal endothelial Rho kinase activity was observed at cell-cell contact sites, in vitro and in situ. Thrombin enhanced MYPT phosphorylation at F-actin stress fibers. Inhibition of basal Rho kinase activity for 24 hours or depletion of Rho kinase (ROCK-I and -II) by siRNA disrupted endothelial barrier integrity, opposite to the previously observed protection from the thrombin-enhanced endothelial permeability. This barrier dysfunction could not be explained by changes in RhoA, Rac1, eNOS, or apoptosis. Remarkably, basal Rho kinase activity was essential for proper expression of the adhesion molecule VE-cadherin.

Conclusions—Rho kinase has opposing activities in regulation of endothelial barrier function: (1) an intrinsic barrier-protective activity at the cell margins, and (2) an induced barrier-disruptive activity at contractile F-actin stress fibers. These findings may have implications for long-term antivascular leak therapy.
Retention of Low-Density Lipoprotein in Atherosclerotic Lesions of the Mouse
Authors: Gustafsson Maria , Levin Malin , Skålén Kristina , Perman Jeanna , Fridén Vincent , Jirholt Pernilla , Olofsson Sven-Olof , Fazio Sergio , Linton MacRae F. , Semenkovich Clay F. , Olivecrona Gunilla , Borén Jan
Published: August 2007

Direct binding of apolipoprotein (apo)B-containing lipoproteins to proteoglycans is the initiating event in atherosclerosis, but the processes involved at later stages of development are unclear. Here, we investigated the importance of the apoB–proteoglycan interaction in the development of atherosclerosis over time and investigated the role of lipoprotein lipase (LPL) to facilitate low-density lipoprotein (LDL) retention at later stages of development. Atherosclerosis was analyzed in apoB transgenic mice expressing LDL with normal (control LDL) or reduced proteoglycan-binding (RK3359-3369SA LDL) activity after an atherogenic diet for 0 to 40 weeks. The initiation of atherosclerosis was delayed in mice expressing RK3359-3369SA LDL, but they eventually developed the same level of atherosclerosis as mice expressing control LDL. Retention studies in vivo showed that although higher levels of
131
I-tyramine cellobiose–labeled control LDL (
131
I-TC-LDL) were retained in nonatherosclerotic aortae compared with RK3359-3369SA
131
I-TC-LDL, the retention was significantly higher and there was no difference between the groups in atherosclerotic aortae. Lower levels of control
125
I-TC-LDL and RK3359-3369SA
125
I-TC-LDL were retained in atherosclerotic aortae from
ldlr
−/−
mice transplanted with
lpl
−/−
compared with
lpl
+/+
bone marrow. Uptake of control LDL or RK3359-3369SA LDL into macrophages with specific expression of human catalytically active or inactive LPL was increased compared with control macrophages. Furthermore, transgenic mice expressing catalytically active or inactive LPL developed the same extent of atherosclerosis. Thus, retention of LDL in the artery wall is initiated by direct LDL–proteoglycan binding but shifts to indirect binding with bridging molecules such as LPL.
Blood Pressure in Relation to the Incidence of Cerebral Infarction and Intracerebral Hemorrhage
Authors: Zia Elisabet , Hedblad Bo , Pessah-Rasmussen Hélène , Berglund Göran , Janzon Lars , Engström Gunnar
Published: August 2007

Background and Purpose—

Data regarding the association between blood pressure level and incidence of stroke subtype, especially primary intracerebral hemorrhage (PICH) subtypes, is sparse. This population-based study explored the relationship between blood pressure and the incidence of cerebral infarction, and PICH, with lobar and nonlobar location.

Methods—

Risk factors were assessed in 27 702 men and women without prior stroke from the city of Malmö, Sweden.

Results—

Mean age was 58.1 years. In all, 701 subjects had stroke (613 cerebral infarction and 88 PICH) during the follow-up period (mean, 7.5 years). The age- and sex-standardized incidences of cerebral infarction in subjects with hypertension grade 3 (≥180/110 mm Hg) and normal blood pressure (<140/90 mm Hg) were 6.8 and 1.7 per 1000 person-years, respectively. Compared with the normotensive group, the adjusted relative risk of cerebral infarction was 3.4 (95% CI: 2.6 to 4.5) in subjects with hypertension grade 3. The corresponding incidences of lobar PICH were 0.5 versus 0.08 per 1000 person-years, respectively (adjusted relative risk: 9.2, 95% CI: 2.6 to 32.6) and for nonlobar PICH 1.6 versus 0.09 per 1000 person-years, respectively (adjusted relative risk: 25.9, 95% CI: 8.2 to 82.3).

Conclusions—

The incidence of hemorrhagic and ischemic stroke increased progressively with increasing blood pressure. Although hypertension was associated with substantially higher incidence rates and absolute numbers of cerebral infarction, which is most important in the public health perspective, the relationship with nonlobar PICH was strongest in terms of relative risks.
Beneficial Effects of Hematopoietic Growth Factor Therapy in Chronic Ischemic Stroke in Rats
Authors: Zhao Li-Ru , Berra Hector H. , Duan Wei-Ming , Singhal Seema , Mehta Jayesh , Apkarian A. Vania , Kessler John A.
Published: August 2007

Background and Purpose—

Stroke is the leading cause of adult disability worldwide. Currently, there is no effective treatment for stroke survivors. Stem cell factor (SCF) and granulocyte-colony stimulating factor (G-CSF) are the growth factors regulating hematopoiesis. We have previously observed that SCF and G-CSF have neuroprotective and functional effects on acute brain ischemia. In the present study, the beneficial effects of SCF and G-CSF on chronic brain ischemia were determined.

Methods—

SCF, G-CSF, or SCF+G-CSF was administered subcutaneously to rats 3.5 months after induction of ischemic stroke by middle cerebral artery occlusion. Neurological deficits were evaluated by limb placement test and foot fault test over time. Field-evoked potential was performed 19 weeks after treatment. Infarct volume was histologically determined using serial coronal sections.

Results—

Significant functional improvement was seen in SCF+G-CSF-treated rats 1, 5, and 17 weeks after injections. SCF alone also improved functional outcome, but it did not show as stable improvement as SCF+G-CSF. No functional benefit was seen in G-CSF-treated rats. Field-evoked potential studies further confirmed the behavioral data that the normal pattern of neuronal activity was reestablished in the lesioned brain of the rats with good functional outcome. Interestingly, infarction volume was also significantly reduced in SCF+G-CSF-treated rats.

Conclusion—

These data provide first evidence that functional restoration in chronic brain ischemia can be attained using hematopoietic growth factors.
Discontinuation of Statin Therapy and Clinical Outcome After Ischemic Stroke
Authors: Colivicchi Furio , Bassi Andrea , Santini Massimo , Caltagirone Carlo
Published: August 2007

Background and Purpose—

The majority of patients with previous ischemic stroke are expected to benefit significantly from long-term statin therapy. However, discontinuation of medication therapy frequently occurs in clinical practice. The aim of this study was to assess the impact of discontinued statin therapy on clinical outcome in patients discharged after an acute ischemic stroke.

Methods—

The study population included 631 consecutive stroke survivors (322 men and 309 women; mean±SD age, 70.2±7.6 years) without clinical evidence of coronary heart disease. All patients were discharged on statin therapy and were followed up for 12 months after the acute ischemic stroke.

Results—

Within 12 months from discharge, 246 patients (38.9%) discontinued statin therapy; the mean time from discharge to statin discontinuation was 48.6±54.9 days (median time, 30 days; interquartile range, 18 to 55 days). During follow-up, 116 patients died (1-year probability of death=0.18; 95% CI, 0.15 to 0.21). Multivariate analysis demonstrated that after adjustment for all confounders and interactions, statin therapy discontinuation (hazard ratio=2.78; 95% CI, 1.96 to 3.72;
P
=0.003) was an independent predictor of all-cause 1-year mortality.

Conclusions—

A large number of patients discontinue their use of statins early after acute stroke. Moreover, patients discontinuing statins have a significantly increased mortality during the first year after the acute cerebrovascular event. These findings suggest that patient care should be improved during the transition from a hospital setting to outpatient primary care.
A New Hippocampal Model for Examining Intracerebral Hemorrhage-Related Neuronal Death
Authors: Song Shuijiang , Hua Ya , Keep Richard F. , Hoff Julian T. , Xi Guohua
Published: August 2007

Background and Purpose—

There is an urgent need to develop a model in which to study the mechanism of intracerebral hemorrhage-induced neuronal death in vivo.

Methods—

This study was divided into 2 parts: (1) Rats received either an infusion of hemoglobin, ferrous iron, or saline into the right hippocampus; (2) Rats had an infusion of hemoglobin and then were treated with either deferoxamine or vehicle. Rats were killed for hippocampus size, DNA damage, and neuronal death measurements.

Results—

Compared with saline, hemoglobin or iron injection caused hippocampal neuronal death. Systemic use of deferoxamine reduced hemoglobin-induced DNA damage, hippocampal neuronal death, and atrophy.

Conclusions—

This article demonstrates a new model and indicates that iron has a key role in hemoglobin–induced neuronal death.
Asymmetry of the Tripole Rainfall Pattern during the East Asian Summer
Authors: Hsu Huang-Hsiung , Lin Shih-Ming
Published: August 2007

This study investigates the tripole rainfall pattern in East Asia during the northern summer. The tripole pattern is characterized by a zonally elongated and meridionally banded structure with signs changing alternatively from 20° to 50°N along the East Asian coast. The positive (negative) phase of the pattern is characterized by more (less) rainfall in central-eastern China, Japan, and South Korea, and less (more) rainfall in northern and southern China. Asymmetry between the positive and negative phases is one of the key findings of this study. The tripole pattern is closely associated with two wavelike patterns: the Pacific–Japan pattern and the Silk Road pattern. The former, which emanates from the tropical western Pacific to extratropical East Asia, is more evident in the positive phase, while the latter, emanating across the Eurasian continent, is more evident in the negative phase. The positive phase appears to have a stronger tropical connection, while the negative phase has a stronger extratropical connection. The positive and negative phases are associated with the positive and negative SSTA in the equatorial eastern Pacific, respectively. It is suggested that in the positive phase the zonally oriented overturning circulation driven by the positive SSTA in the equatorial eastern Pacific induces heating anomalies in the tropical western Pacific, which in turn triggers a wavelike pattern emanating northward toward extratropical East Asia. This indirect SSTA effect is not evident in the negative phase, which is predominantly affected by the extratropical Eurasian wavelike perturbations. On the other hand, anomalous heating over the eastern Tibetan Plateau seems to induce the eastward-propagating wavelike structure in both phases. It is suggested that the tripole pattern is a result of the amplification of an intrinsic dynamic mode that can be triggered by various factors despite their different origins.
Global Warming and the Weakening of the Tropical Circulation
Authors: Vecchi Gabriel A. , Soden Brian J.
Published: August 2007

This study examines the response of the tropical atmospheric and oceanic circulation to increasing greenhouse gases using a coordinated set of twenty-first-century climate model experiments performed for the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4). The strength of the atmospheric overturning circulation decreases as the climate warms in all IPCC AR4 models, in a manner consistent with the thermodynamic scaling arguments of Held and Soden. The weakening occurs preferentially in the zonally asymmetric (i.e., Walker) rather than zonal-mean (i.e., Hadley) component of the tropical circulation and is shown to induce substantial changes to the thermal structure and circulation of the tropical oceans. Evidence suggests that the overall circulation weakens by decreasing the frequency of strong updrafts and increasing the frequency of weak updrafts, although the robustness of this behavior across all models cannot be confirmed because of the lack of data. As the climate warms, changes in both the atmospheric and ocean circulation over the tropical Pacific Ocean resemble “El Niño–like” conditions; however, the mechanisms are shown to be distinct from those of El Niño and are reproduced in both mixed layer and full ocean dynamics coupled climate models. The character of the Indian Ocean response to global warming resembles that of Indian Ocean dipole mode events. The consensus of model results presented here is also consistent with recently detected changes in sea level pressure since the mid–nineteenth century.
An Integrated Model for Glucose and Insulin Regulation in Healthy Volunteers and Type 2 Diabetic Patients Following Intravenous Glucose Provocations
Authors: Silber Hanna E. , Jauslin Petra M. , Frey Nicolas , Gieschke Ronald , Simonsson Ulrika S. H. , Karlsson Mats O.
Published: August 2007

An integrated model for the regulation of glucose and insulin concentrations following intravenous glucose provocations in healthy volunteers and type 2 diabetic patients was developed. Data from 72 individuals were included. Total glucose, labeled glucose, and insulin concentrations were determined. Simultaneous analysis of all data by nonlinear mixed effect modeling was performed in NONMEM. Integrated models for glucose, labeled glucose, and insulin were developed. Control mechanisms for regulation of glucose production, insulin secretion, and glucose uptake were incorporated. Physiologically relevant differences between healthy volunteers and patients were identified in the regulation of glucose production, elimination rate of glucose, and secretion of insulin. The model was able to describe the insulin and glucose profiles well and also showed a good ability to simulate data. The features of the present model are likely to be of interest for analysis of data collected in antidiabetic drug development and for optimization of study design.
Safety, Tolerability, QTc Evaluation, and Pharmacokinetics of Single and Multiple Doses of Enzastaurin HCl (LY317615), a Protein Kinase C‐β Inhibitor, in Healthy Subjects
Authors: Welch Pamela A. , Sinha Vikram P. , Cleverly Ann L. , Darstein Christelle , Flanagan Shawn D. , Musib Luna C.
Published: August 2007

The safety, tolerability, and pharmacokinetics of orally administered enzastaurin were evaluated in 2 placebo‐controlled, dose escalation studies in healthy subjects. In the first human dose study, single doses (2–400 mg) were evaluated, with 22 subjects receiving enzastaurin. The mean half‐lives of enzastaurin and its metabolites ranged from approximately 12 to 40 hours. The longer half‐life of the major circulating and pharmacologically active metabolite allowed once‐a‐day dosing and predicted that steady state would be achieved within 2 weeks of daily oral dosing in all subjects. In the multiple‐dose study, daily doses (25–400 mg) were examined, with 24 subjects receiving at least 1 dose. The most common adverse events related to enzastaurin were headache, sleepiness, diarrhea, and nausea. No clinically significant changes in QTc intervals were observed. Overall, enzastaurin was well tolerated in healthy subjects, and the planned maximum dose was achieved in both studies.
Pharmacokinetic Drug‐Drug Interaction Potentials for Therapeutic Monoclonal Antibodies: Reality Check
Authors: Seitz Kathleen , Zhou Ghui
Published: August 2007

A formal assessment of the drug‐drug interaction potential of any investigational drug product often requires multiple metabolic and pharmacokinetic evaluations. In contrast to a small‐molecule drug, investigating the drug‐drug interaction potential of a monoclonal antibody is inherently complicated. High molecular weight monoclonal antibodies are often genetically engineered to demonstrate strong specificity for a particular human antigen target. Consequently, monoclonal antibodies usually have few clinically relevant animal models—other than nonhuman primates—in which to conduct appropriate nonclinical studies. Likewise, clinical drug‐drug interaction studies of monoclonal antibodies with long elimination half‐lives pose definite operational challenges as conventional crossover studies with adequate washout periods are difficult to conduct. Furthermore, the current regulatory guidance on the design and conduct of in vitro and in vivo drug‐drug interaction studies applies more readily to small‐molecule drugs than protein‐based biologics. Nevertheless, a certain amount of clinically useful information has begun to emerge from the published literature on drug‐drug interaction potentials of therapeutic monoclonal antibodies. This article provides a systematic review of the current literature and offers some practical considerations for the design and conduct of pharmacokinetic drug‐drug interaction assessments involving novel monoclonal antibodies. Ideally, these evaluations should be performed throughout all stages of drug development. In particular, pharmacokinetic interaction studies with any marketed drugs that are likely to be coadministered with the monoclonal antibody will yield the most clinically useful information for practitioners and patients alike.
Methodological Review of Intimate Partner Violence Prevention Research
Authors: Murray Christine E. , Graybeal Jennifer
Published: August 2007

The authors present a methodological review of empirical program evaluation research in the area of intimate partner violence prevention. The authors adapted and utilized criterion-based rating forms to standardize the evaluation of the methodological strengths and weaknesses of each study. The findings indicate that the limited amount of empirical research related to intimate partner violence prevention demonstrates some consistent methodological strengths and limitations. The authors conclude with a presentation of recommendations for further research in the area of intimate partner violence prevention.
Intimate Partner Violence, Depression, and Posttraumatic Stress Disorder as Additional Predictors of Low Birth Weight Infants Among Low-Income Mothers
Authors: Rosen Daniel , Seng Julia S. , Tolman Richard M. , Mallinger Gayle
Published: August 2007

Estimates of intimate partner violence (IPV) during pregnancy vary by population being studied, measures, and other methodological limitations, hindering the ability to gauge the relationship between IPV and negative birth outcomes. The authors report aggregated data from a subsample ( n = 148) of the first three waves of the Women's Employment Study. The authors compared groups of women who did and did not give birth to low birth weight infants on demographic, material deprivation, risk behavior, mental health, and IPV factors. The prevalence of domestic violence was more than twice as high for women with low birth weight infants as those women who had a normal weight infant. When considering additional risk factors, including food insufficiency, substance dependence, and depression and/or posttraumatic stress disorder, IPV remained a significant indicator, but it was most strongly associated with low birth weight among women also experiencing depression and/or posttraumatic stress disorder.
Criminal Profiles of Violent Juvenile Sex and Violent Juvenile Non–Sex Offenders
Authors: van Wijk Anton Ph. , Mali Bas R. F. , Bullens Ruud A. R. , Vermeiren Robert R.
Published: August 2007

Few studies have longitudinally investigated the criminal profiles of violent juvenile sex and violent juvenile non–sex offenders. To make up for this lack, this study used police records of juveniles to determine the nature of the criminal profiles of violent sex offenders ( n = 226) and violent non–sex offenders ( n = 4,130). All offenders committed their first offense in 1996 and were followed for 7 years. Results showed that violent sex offenders and violent non–sex offenders cannot be considered a homogeneous group because of different background characteristics and criminal profiles. Sex and violent offenses often constitute a small part of a broader criminal pattern. Further research is necessary to reveal in more detail the developmental and criminological patterns of violent and sexual delinquency. Treatment and intervention programs may benefit from this.
Clonal regulatory T cells specific for a red blood cell autoantigen in human autoimmune hemolytic anemia
Authors: Ward Frank J. , Hall Andrew M. , Cairns Lindsay S. , Leggat Arabella S. , Urbaniak Stanislaw J. , Vickers Mark A. , Barker Robert N.
Published: August 2007

Regulatory T (Tr) cells have the potential to treat immune-mediated disease, but cloning such cells for study from patients with autoimmune disease has proven difficult. Here, we describe autoantigen-specific, interleukin-10 (IL-10)–secreting Tr cell clones recovered ex vivo from a patient with autoimmune hemolytic anemia (AIHA) and characterize their phenotype, origin, and regulatory function. These IL-10+ Tr cells recognized a peptide, 72H-86L, derived from the Rh red blood cell autoantigen and shared phenotypic characteristics with both natural and inducible Tr cells. The clones also expressed different Tr markers depending on activation state: high levels of CD25 and LAG-3 when expanding nonspecifically, but FoxP3 after activation by the autoantigen they recognize. Despite a discrete Tr phenotype, these cells stably expressed the T helper 1 (Th1) signature transcription factor T-bet, suggesting they derive from Th1 T cells. Finally, the contribution of CTLA-4 in activating these IL-10+ Tr cells was confirmed by analyzing responses to transgenic B7.1-like molecules that preferentially bind either CD28 or CTLA-4. Overall, these Tr cells have a functional phenotype different from those described in previous studies of human Tr populations, which have not taken account of antigen specificity, and understanding their properties will enable them to be exploited therapeutically in AIHA.
Biomarkers in respiratory tract infections: diagnostic guides to antibiotic prescription, prognostic markers and mediators
Authors: Christ-Crain M. , Müller B.
Published: August 2007

Used appropriately, biomarkers improve the assessment of respiratory tract infections and sepsis. Most prominently, circulating procalcitonin levels increase by a factor of several tens of thousands during sepsis. Using a sensitive assay, procalcitonin safely and markedly reduces antibiotic usage in respiratory tract infections and nonbacterial meningitis. Procalcitonin is the protopye of hormokine mediators. The term “hormokine” encompasses the cytokine-like behaviour of hormones during inflammation and infections. The concept is based on a ubiquitous expression of calcitonin peptides during sepsis. Adrenomedullin, another member of the calcitonin peptide superfamily, was shown to complement and improve the current prognostic assessment in lower respiratory tract infections. Other peptides share some features of hormokines,e.g.natriuretic peptide and copeptin. Hormokines are not only biomarkers of infection but are also pivotal inflammatory mediators. Like all mediators, their role during systemic infections is basically beneficial, possibly to combat invading microbes. However, at increased levels they can become harmful for their host. Multiple mechanisms of action were proposed. In several animal models the modulation and neutralisation of hormokines during infection was shown to improve survival, and thus might open new treatment options for severe infections, especially of the respiratory tract.
The mitochondrial genome of Phallusia mammillata and Phallusia fumigata (Tunicata, Ascidiacea): high genome plasticity at intra-genus level
Authors: Iannelli Fabio , Griggio Francesca , Pesole Graziano , Gissi Carmela
Published: August 2007

Background

Within Chordata, the subphyla Vertebrata and Cephalochordata (lancelets) are characterized by a remarkable stability of the mitochondrial (mt) genome, with constancy of gene content and almost invariant gene order, whereas the limited mitochondrial data on the subphylum Tunicata suggest frequent and extensive gene rearrangements, observed also within ascidians of the same genus.

Results

To confirm this evolutionary trend and to better understand the evolutionary dynamics of the mitochondrial genome in Tunicata Ascidiacea, we have sequenced and characterized the complete mt genome of two congeneric ascidian species, Phallusia mammillata and Phallusia fumigata (Phlebobranchiata, Ascidiidae). The two mtDNAs are surprisingly rearranged, both with respect to one another and relative to those of other tunicates and chordates, with gene rearrangements affecting both protein-coding and tRNA genes. The new data highlight the extraordinary variability of ascidian mt genome in base composition, tRNA secondary structure, tRNA gene content, and non-coding regions (number, size, sequence and location). Indeed, both Phallusia genomes lack the trnD gene, show loss/acquisition of DHU-arm in two tRNAs, and have a G+C content two-fold higher than other ascidians. Moreover, the mt genome of P. fumigata presents two identical copies of trnI, an extra tRNA gene with uncertain amino acid specificity, and four almost identical sequence regions. In addition, a truncated cytochrome b, lacking a C-terminal tail that commonly protrudes into the mt matrix, has been identified as a new mt feature probably shared by all tunicates.

Conclusion

The frequent occurrence of major gene order rearrangements in ascidians both at high taxonomic level and within the same genus makes this taxon an excellent model to study the mechanisms of gene rearrangement, and renders the mt genome an invaluable phylogenetic marker to investigate molecular biodiversity and speciation events in this largely unexplored group of basal chordates.
Glycerate kinase of the hyperthermophilic archaeon Thermoproteus tenax: new insights into the phylogenetic distribution and physiological role of members of the three different glycerate kinase classes
Authors: Kehrer Daniel , Ahmed Hatim , Brinkmann Henner , Siebers Bettina
Published: August 2007

Background

The presence of the branched Entner-Doudoroff (ED) pathway in two hyperthermophilic Crenarchaea, the anaerobe Thermoproteus tenax and the aerobe Sulfolobus solfataricus, was suggested. However, so far no enzymatic information of the non-phosphorylative ED branch and especially its key enzyme – glycerate kinase – was available. In the T. tenax genome, a gene homolog with similarity to putative hydroxypyruvate reductase/glycerate dehydrogenase and glycerate kinase was identified.

Results

The encoding gene was expressed in E. coli in a recombinant form, the gene product purified and the glycerate kinase activity was confirmed by enzymatic studies. The enzyme was active as a monomer and catalyzed the ATP-dependent phosphorylation of D-glycerate forming exclusively 2-phosphoglycerate. The enzyme was specific for glycerate and highest activity was observed with ATP as phosphoryl donor and Mg2+ as divalent cation. ATP could be partially replaced by GTP, CTP, TTP and UTP. The enzyme showed high affinity for D-glycerate (Km 0.02 ± 0.01 mM, Vmax of 5.05 ± 0.52 U/mg protein) as well as ATP (Km of 0.03 ± 0.01 mM, Vmax of 4.41 ± 0.04 U/mg protein), although at higher glycerate concentrations, substrate inhibition was observed. Furthermore, the enzyme was inhibited by its product ADP via competitive inhibition. Data bank searches revealed that archaeal glycerate kinases are members of the MOFRL (multi-organism fragment with rich leucine) family, and homologs are found in all three domains of life.

Conclusion

A re-evaluation of available genome sequence information as well as biochemical and phylogenetic studies revealed the presence of the branched ED pathway as common route for sugar degradation in Archaea that utilize the ED pathway. Detailed analyses including phylogenetic studies demonstrate the presence of three distinct glycerate kinase classes in extant organisms that share no common origin. The affiliation of characterized glycerate kinases with the different enzyme classes as well as their physiological/cellular function reveals no association with particular pathways but a separate phylogenetic distribution. This work highlights the diversity and complexity of the central carbohydrate metabolism. The data also support a key function of the conversion of glycerate to 2- or 3-phosphoglycerate via glycerate kinase in funneling various substrates into the common EMP pathway for catabolic and anabolic purposes.
Gene expression profiling reveals different pathways related to Abl and other genes that cooperate with c-Myc in a model of plasma cell neoplasia
Authors: Park Eun Sung , Shaughnessy John D , Gupta Shalu , Wang Hongyang , Lee Ju-Seog , Woo Hyun Goo , Zhan Fenghuang , Owens James D , Potter Michael , Janz Siegfried , Mushinski J Frederic
Published: August 2007

Background

To elucidate the genes involved in the neoplastic transformation of B cells, global gene expression profiles were generated using Affymetrix U74Av2 microarrays, containing 12,488 genes, for four different groups of mouse B-cell lymphomas and six subtypes of pristane-induced mouse plasma cell tumors, three of which developed much earlier than the others.

Results

Unsupervised hierarchical cluster analysis exhibited two main sub-clusters of samples: a B-cell lymphoma cluster and a plasma cell tumor cluster with subclusters reflecting mechanism of induction. This report represents the first step in using global gene expression to investigate molecular signatures related to the role of cooperating oncogenes in a model of Myc-induced carcinogenesis. Within a single subgroup, e.g., ABPCs, plasma cell tumors that contained typical T(12;15) chromosomal translocations did not display gene expression patterns distinct from those with variant T(6;15) translocations, in which the breakpoint was in the Pvt-1 locus, 230 kb 3' of c-Myc, suggesting that c-Myc activation was the initiating factor in both. When integrated with previously published Affymetrix array data from human multiple myelomas, the IL-6-transgenic subset of mouse plasma cell tumors clustered more closely with MM1 subsets of human myelomas, slow-appearing plasma cell tumors clustered together with MM2, while plasma cell tumors accelerated by v-Abl clustered with the more aggressive MM3-MM4 myeloma subsets. Slow-appearing plasma cell tumors expressed Socs1 and Socs2 but v-Abl-accelerated plasma cell tumors expressed 4–5 times as much. Both v-Abl-accelerated and non-v-Ab l-associated tumors exhibited phosphorylated STAT 1 and 3, but only v-Abl-accelerated plasma cell tumors lost viability and STAT 1 and 3 phosphorylation when cultured in the presence of the v-Abl kinase inhibitor, STI-571. These data suggest that the Jak/Stat pathway was critical in the transformation acceleration by v-Abl and that v-Abl activity remained essential throughout the life of the tumors, not just in their acceleration. A different pathway appears to predominate in the more slowly arising plasma cell tumors.

Conclusion

Gene expression profiling differentiates not only B-cell lymphomas from plasma cell tumors but also distinguishes slow from accelerated plasma cell tumors. These data and those obtained from the sensitivity of v-Abl-accelerated plasma cell tumors and their phosphorylated STAT proteins indicate that these similar tumors utilize different signaling pathways but share a common initiating genetic lesion, a c-Myc-activating chromosome translocation.
Global analysis of host response to induction of a latent bacteriophage
Authors: Osterhout Robin E , Figueroa Israel A , Keasling Jay D , Arkin Adam P
Published: August 2007

Background

The transition from viral latency to lytic growth involves complex interactions among host and viral factors, and the extent to which host physiology is buffered from the virus during induction of lysis is not known. A reasonable hypothesis is that the virus should be evolutionarily selected to ensure host health throughout induction to minimize its chance of reproductive failure. To address this question, we collected transcriptional profiles of Escherichia coli and bacteriophage lambda throughout lysogenic induction by UV light.

Results

We observed a temporally coordinated program of phage gene expression, with distinct early, middle and late transcriptional classes. Our study confirmed known host-phage interactions of induction of the heat shock regulon, escape replication, and suppression of genes involved in cell division and initiation of replication. We identified 728 E. coli genes responsive to prophage induction, which included pleiotropic stress response pathways, the Arc and Cpx regulons, and global regulators crp and lrp. Several hundred genes involved in central metabolism, energy metabolism, translation and transport were down-regulated late in induction. Though statistically significant, most of the changes in these genes were mild, with only 140 genes showing greater than two-fold change.

Conclusion

Overall, we observe that prophage induction has a surprisingly low impact on host physiology. This study provides the first global dynamic picture of how host processes respond to lambda phage induction.
High resolution melting for mutation scanning of TP53exons 5–8
Authors: Krypuy Michael , Ahmed Ahmed Ashour , Etemadmoghadam Dariush , Hyland Sarah J ,   Australian Ovarian Cancer Study Group, deFazio Anna , Fox Stephen B , Brenton James D , Bowtell David D , Dobrovic Alexander
Published: August 2007

Background

p53 is commonly inactivated by mutations in the DNA-binding domain in a wide range of cancers. As mutant p53 often influences response to therapy, effective and rapid methods to scan for mutations in TP53 are likely to be of clinical value. We therefore evaluated the use of high resolution melting (HRM) as a rapid mutation scanning tool for TP53 in tumour samples.

Methods

We designed PCR amplicons for HRM mutation scanning of TP53 exons 5 to 8 and tested them with DNA from cell lines hemizygous or homozygous for known mutations. We assessed the sensitivity of each PCR amplicon using dilutions of cell line DNA in normal wild-type DNA. We then performed a blinded assessment on ovarian tumour DNA samples that had been previously sequenced for mutations in TP53 to assess the sensitivity and positive predictive value of the HRM technique. We also performed HRM analysis on breast tumour DNA samples with unknown TP53 mutation status.

Results

One cell line mutation was not readily observed when exon 5 was amplified. As exon 5 contained multiple melting domains, we divided the exon into two amplicons for further screening. Sequence changes were also introduced into some of the primers to improve the melting characteristics of the amplicon. Aberrant HRM curves indicative of TP53 mutations were observed for each of the samples in the ovarian tumour DNA panel. Comparison of the HRM results with the sequencing results revealed that each mutation was detected by HRM in the correct exon. For the breast tumour panel, we detected seven aberrant melt profiles by HRM and subsequent sequencing confirmed the presence of these and no other mutations in the predicted exons.

Conclusion

HRM is an effective technique for simple and rapid scanning of TP53 mutations that can markedly reduce the amount of sequencing required in mutational studies of TP53.
Outcome related to impact on daily living: preliminary validation of the ORIDL instrument
Authors: Reilly David , Mercer Stewart W , Bikker Annemieke P , Harrison Tansy
Published: September 2007

Background

The challenge of finding practical, patient-rated outcome measures is a key issue in the evaluation of health care systems and interventions. The ORIDL (Outcome in Relation to Impact on Daily Living) instrument (formerly referred to as the Glasgow Homoeopathic Hospital Outcomes Scale or GHHOS) has been developed to measure patient's views of the outcome of their care by asking about change, and relating this to impact on daily life. The aim of the present paper is to describe the background and potential uses of the ORIDL, and to report on its preliminary validation in a series of three studies in secondary and primary care.

Methods

In the first study, 105 patients attending the Glasgow Homoeopathic Hospital (GHH) were followed-up at 12 months and changes in health status were measured by the EuroQol (EQOL) and the ORIDL. In the second study, 187 new patients at the GHH were followed-up at 3, 12, and 33 months, using the ORIDL, the Short Form 12 (SF-12), and the Measure Yourself Medical Outcome Profile (MYMOP). In study three, 323 patients in primary care were followed for 1 month post-consultation using the ORIDL and MYMOP. In all 3 studies the Patient Enablement Instrument (PEI) was also used as an outcome measure.

Results

Study 1 showed substantial improvements in main complaint and well-being over 12 months using the ORIDL, with two-thirds of patients reporting improvements in daily living. These improvements were not significantly correlated with changes in serial measures of the EQOL between baseline and 12 months, but were correlated with the EQOL transitions measure. Study 2 showed step-wise improvements in ORIDL scores between 3 and 33 months, which were only weakly associated with similar changes in SF-12 scores. However, MYMOP change scores correlated well with ORIDL scores at all time points. Study 3 showed similar high correlations between ORIDL scores and MYMOP scores. In all 3 studies, ORIDL scores were also significantly correlated with PEI-outcome scores.

Conclusion

There is significant agreement between patient outcomes assessed by the ORIDL and the EQOL transition scale, the MYMOP, and the PEI-outcome instrument, suggesting that the ORIDL may be a valid and sensitive tool for measuring change in relation to impact on life.
The impact of generational change and retirement on psychiatry to 2025
Authors: Fletcher Susan L , Schofield Deborah J
Published: September 2007

Background

Australia is currently experiencing widespread shortages of psychiatrists. The changing nature of the workforce and increasing demand mean that these shortages are unlikely to ease. This study aims to identify demographic change and retirement patterns of the Australian psychiatry workforce from 1995 to 2003, and the implications of those changes for future workforce planning.

Methods

Data from the Australian Institute of Health and Welfare (AIHW) Medical Labour Force Survey from 1995 to 2003 is used to examine ageing of the psychiatry workforce and attrition of psychiatrists aged 50 years and over. Future attrition from the workforce is projected to 2025.

Results

Sixty two percent of psychiatrists practicing in the year 2000 are predicted to have retired by 2025. Most psychiatrists continue to work until late in life, with only 18 per cent retiring before age 65. The psychiatry workforce aged significantly between 1995 and 2003 (p < 0.001), with men older than women in both years. A reduction in hours worked by psychiatrists reflects both the increasing proportion of females and the older members of the profession reducing their hours in preparation for retirement.

Conclusion

The impact of ageing of the workforce may be more immediate for psychiatry than for some other health professions. With the growing proportion of females and their typically lower workforce participation, more than one younger psychiatrist will be required to replace each of the mostly male retirees.
The SCI Exercise Self-Efficacy Scale (ESES): development and psychometric properties
Authors: Kroll Thilo , Kehn Matthew , Ho Pei-Shu , Groah Suzanne
Published: August 2007

Background

Rising prevalence of secondary conditions among persons with spinal cord injury (SCI) has focused recent attention to potential health promotion programs designed to reduce such adverse health conditions. A healthy lifestyle for people with SCI, including and specifically, the adoption of a vigorous exercise routine, has been shown to produce an array of health benefits, prompting many providers to recommend the implementation of such activity to those with SCI. Successfully adopting such an exercise regimen however, requires confidence in one's ability to engage in exercise or exercise self-efficacy. Exercise self-efficacy has not been assessed adequately for people with SCI due to a lack of validated and reliable scales, despite self efficacy's status as one of the most widely researched concepts and despite its broad application in health promotion studies. Exercise self efficacy supporting interventions for people with SCI are only meaningful if appropriate measurement tools exist. The objective of our study was to develop a psychometrically sound exercise self-efficacy self-report measure for people with SCI.

Methods

Based on literature reviews, expert comments and cognitive testing, 10 items were included and made up the 4-point Likert SCI Exercise Self-Efficacy Scale (ESES) in its current form. The ESES was administered as part of the first wave of a nationwide survey (n = 368) on exercise behavior and was also tested separately for validity in four groups of individuals with SCI. Reliability and validity testing was performed using SPSS 12.0.

Results

Cronbach's alpha was .9269 for the ESES. High internal consistency was confirmed in split-half (EQ Length Spearman Brown = .8836). Construct validity was determined using principal component factor analysis by correlating the aggregated ESES items with the Generalised Self Efficacy Scale (GSE). We found that all items loaded on one factor only and that there was a statistically significant correlation between Exercise Self-Efficacy Scale (ESES) and Generalised Self Efficacy Scale (GSE) (Spearman RHO = .316; p < .05; n = 53, 2-sided).

Conclusion

Preliminary findings indicate that the ESES is a reliable instrument with high internal consistency and scale integrity. Content validity both in terms of face and construct validity is satisfactory.
Multiple organ failure after trauma affects even long-term survival and functional status
Authors: Ulvik Atle , Kvåle Reidar , Wentzel-Larsen Tore , Flaatten Hans
Published: September 2007

Background

The aim of this study was to assess the incidence of organ failure in trauma patients treated in an intensive care unit (ICU), and to study the relationship between organ failure and long-term survival and functional status.

Methods

This is a cohort study of all adult ICU trauma patients admitted to a university hospital during 1998 to 2003. Organ failure was quantified by the Sequential Organ Failure Assessment (SOFA) score. A telephone interview was conducted in 2005 (2 to 7 years after trauma) using the Karnofsky Index to measure functional status, and the Glasgow Outcome Score to measure recovery.

Results

Of the 322 patients included, 47% had multiple organ failure (MOF), and 28% had single organ failure. In a Cox regression, MOF increased the overall risk of death 6.0 times. At follow-up, 242 patients (75%) were still alive. Patients with MOF had 3.9 times greater odds for requiring personal assistance in activities of daily living compared to patients without organ failure. Long-term survival and functional status were the same for patients suffering single organ failure and no organ failure. Complete recovery occurred in 52% of survivors, and 87% were able to look after themselves.

Conclusion

Almost half of the ICU trauma patients had MOF. While single organ failure had no impact on long-term outcomes, the presence of MOF greatly increased mortality and the risk of impaired functional status. MOF expressed by SOFA score may be used to define trauma patients at particular risk for poor long-term outcomes.