bluuebunny/crossref_metadata_2025 huggingface dataset:
Dispersed lignin in tracheary elements treated with cellulose synthesis inhibitors provides evidence that molecules of the secondary cell wall mediate wall patterning
Authors: Taylor James G. , Owen T. Page , Koonce Linda T. , Haigler Candace H.
Published: February 2005

Mesophyll cells of Zinnia elegans var. Envy that had been induced to differentiate into tracheary elements (TEs) in suspension culture were treated with the cellulose synthesis inhibitor 2,6‐dichlorobenzonitrile (DCB). The deposition of cellulose into the patterned secondary cell wall thickenings typical of TEs was inhibited as demonstrated by reduced incorporation of [14C]glucose into acetic/nitric insoluble material and absence of cellulose detectable by fluorescence after staining with Tinopal LPW, polarization optics, or labeling with a specific cellulase. Respiration as indicated by release of 14CO2 was inhibited to a much lesser extent, supporting a selective mechanism of action of DCB on the cellulose biosynthetic pathway. Patterned secondary cell wall thickenings were deposited in DCB‐treated TEs, but these were smaller and less regularly shaped than those of control TEs. These cellulose‐depleted thickenings lacked another abundant component of normal thickenings, the hemicellulose xylan, as indicated by absence of labeling with a specific xylanase or an antibody to xylan. DCB‐treated TEs also showed dispersed lignin after staining with phloroglucinol, whereas control TEs contained lignin specifically localized to the secondary cell wall thickenings. Isoxaben, another recently described inhibitor of synthesis of acetic/nitric insoluble cell wall material (putatively cellulose), caused the same absence of detectable cellulose and xylan in the thickenings and dispersed lignin. These data suggest that: (i) the localization of lignin is ultimately dependent on the localization of cellulose; (ii) normal patterned wall assembly in TEs occurs in a self‐perpetuating cascade in which some molecules of the secondary cell wall mediate patterning of others.
The role of colonoscopic endoanal ultrasound scanning (EUS) in selecting patients suitable for resection by transanal endoscopic microsurgery (TEM)
Authors: Glancy D. G. , Pullyblank A. M. , Thomas M. G.
Published: February 2005

Objective  This study was performed to assess the accuracy of colonoscopic endoanal ultrasound scanning (EUS) in the selection of patients with rectal neoplasia suitable for local excision by transanal endoscopic microsurgery (TEM). Our policy is to offer TEM to patients with premalignant (T0) lesions or with T1 tumours that have early disease.

Patients and methods  Data were collected prospectively on all patients undergoing EUS for the assessment of rectal neoplasia at our institution over a six‐year period. A colonoscopic EUS probe was used to determine whether the tumour breached the muscularis propria (the interface between T1 and T2 disease). Subsequently patients underwent surgical resection, including TEM for those with T0/1 disease. The preoperative stage predicted by EUS (uT stage) was compared to the postoperative histopathological stage of the resected specimens (pT stage).

Results  One hundred and fifty‐six EUS examinations were evaluated. Sixty‐two patients went on to have TEM whilst the remaining 94 had another form of surgery. Of the 62 patients undergoing TEM, 3 were overstaged on EUS. No patients were understaged, giving an accuracy of 95%. Of the 94 patients undergoing an alternative procedure, 5 were overstaged on EUS as having T2 tumours when in fact their histology was T1. Accuracy of EUS at predicting more advanced disease fell to 89%, giving an overall accuracy of 92%.

Conclusions  EUS is accurate at predicting T0/1 vs T2 disease in our institution, and we believe that it is a useful modality in assessing patient suitability for local excision.
Thirty‐day mortality from colorectal cancer surgery within a deprived population
Authors: Glen P. , Simpson M. F. , Donnelly L. , Leonard S. , Macdonald A.
Published: February 2005

Objective  A recently published model for predicting 30‐day mortality has been devised using data from 73 hospitals in the UK. Deprivation category was not one of the data sets used in predicting mortality and was not included in formulating this model. We wished to assess if the model was applicable to a population with high deprivation category scores.

Methods  Data on all colorectal cancer operations included in the model (age, ASA, cancer resected, Dukes stage and urgency) had been collected prospectively since January 1999. This data was applied to the model.

Results  Two hundred and thirty patients were included in analysis. Overall predicted mortality was 8.2% and actual mortality 7.8%. Within different categories of deprivation, predicted and actual mortality are similar and not significantly different. 137 patients lived in areas of deprivation category 3–5. Predicted and actual mortality were 8.4% and 8.0%, respectively. In areas of deprivation category 6–7, 91 patients had a predicted and actual mortality of 8.0% and 7.7%.

Conclusion  Although deprivation data was not included in the production of the mathematical model to predict postoperative death, the model appears to predict well in the deprived population. It is likely that poorer socio‐economic status is accounted for by increased ASA and cancer stage.
Diet and colorectal cancer: implications for the obese and devotees of the Atkins diet
Authors: Fleming M. E. , Sales K. M. , Winslet M. C.
Published: February 2005

Colorectal cancer (CRC) is the second most common cause of cancer‐related death in the Western world and its prevalence is increasing. Potential causes of this increase are changes in diet and the increases in obesity seen. This paper looks at the literature surrounding diet and obesity and the links to this increase in CRC. Heralded as a weight loss miracle we investigate whether the literature suggests the Atkins diet may actually do more harm than good by acting to increase an individual's risk of CRC. Obesity has been demonstrated to be a major factor in the increase in CRC although links to changes in diet are more tenuous. Published studies on diet suggest the Atkins diet may help reduce rather than increase the risk of CRC.
Pteridophyte richness, climate and topography in the Iberian Peninsula: comparing spatial and nonspatial models of richness patterns
Authors: Ferrer‐Castán Dolores , Vetaas Ole R.
Published: February 2005

Aim  To describe the spatial variation in pteridophyte species richness; evaluate the importance of macroclimate, topography and within‐grid cell range variables; assess the influence of spatial autocorrelation on the significance of the variables; and to test the prediction of the mid‐domain effect.

Location  The Iberian Peninsula.

Methods  We estimated pteridophyte richness on a grid map with c. 2500 km2 cell size, using published geocoded data of the individual species. Environmental data were obtained by superimposing the grid system over isoline maps of precipitation, temperature, and altitude. Mean and range values were calculated for each cell. Pteridophyte richness was related to the environmental variables by means of nonspatial and spatial generalized least squares models. We also used ordinary least squares regression, where a variance partitioning was performed to partial out the spatial component, i.e. latitude and longitude. Coastal and central cells were compared to test the mid‐domain effect.

Results  Both spatial and nonspatial models showed that pteridophyte richness was best explained by a second‐order polynomial of mean annual precipitation and a quadratic elevation‐range term, although the relative importance of these two variables varied when spatial autocorrelation was accounted for. Precipitation range was weakly significant in a nonspatial multiple model (i.e. ordinary regression), and did not remain significant in spatial models. Richness is significantly higher along the coast than in the centre of the peninsula.

Main conclusions  Spatial autocorrelation affects the statistical significance of explanatory variables, but this did not change the biological interpretation of precipitation and elevation range as the main predictors of pteridophyte richness. Spatial and nonspatial models gave very similar results, which reinforce the idea that water availability and topographic relief control species richness in relatively high‐energy regions. The prediction of the mid‐domain effect is falsified.
Impact of short‐term rainfall fluctuation on interannual land cover change in sub‐Saharan Africa
Authors: Vanacker Veerle , Linderman Marc , Lupo Frederick , Flasse Stephanne , Lambin Eric
Published: February 2005

Aim  Interannual land cover change plays a significant role in food security, ecosystem processes, and regional and global climate modelling. Measuring the magnitude and location and understanding the driving factors of interannual land cover change are therefore of utmost importance to improve our understanding and prediction of these impacts and to better differentiate between natural and human causes of land cover change. Despite advances in quantifying the magnitude of land cover change, the interpretation of the observed land cover change in terms of climatic, ecological and anthropogenic processes still remains a complex issue. In this paper, we map land cover change across sub‐Saharan Africa and examine the influences of rainfall fluctuations on interannual change.

Location  The analysis was applied to sub‐Saharan Africa.

Methods  Ten‐day rainfall estimates (RFE) obtained from National Oceanic and Atmospheric Administration's (NOAA) Climate Prediction Center (CPC) were used to extract information on inter and intra‐annual rainfall fluctuations. The magnitude of land cover change was quantified based on the multitemporal change vector method measuring year‐to‐year differences in bidirectional reflectance distribution function (BRDF) corrected 16‐day enhanced vegetation index (EVI) data from the Moderate Resolution Imaging Spectro‐radiometer (MODIS). Statistical models were used to estimate the relationship between short‐term rainfall variability and the magnitude of land cover change. The analysis was stratified first by physiognomic vegetation type and second by chorological data on species distribution to gain insights into spatial variations in response to short‐term rainfall fluctuations.

Results  The magnitude of land cover change was significantly related to rainfall variability at the 5% level. Stratification considerably strengthened the relationship between the magnitude of change and rainfall variability. Explanatory power of the models ranged from R2 = 0.22 for the unstratified model to 0.40–0.96 for the individual models stratified by patterns of species distribution. The total variability explained by the combined models including the influence of rainfall and differences in vegetation response ranged from 22% for the model not stratified by vegetation to 76% when stratified by chorological data.

Main conclusions  Using this methodology, we were able to measure the contribution of natural variation in precipitation to land cover change. Several ecosystems across sub‐Saharan Africa are highly sensitive to short‐term rainfall variability.
Allelic diversity at the Mhc‐DQA locus of woodmouse populations (Apodemus sylvaticus) present in the islands and mainland of the northern Mediterranean
Authors: De Bellocq Joëlle Goüy , Delarbre Christiane , Gachelin Gabriel , Morand Serge
Published: February 2005

Aim Polymorphism at neutral markers and at MHC loci in rodent populations living on islands is generally low. The main genetic factors that may contribute to a reduced level of genetic variability are genetic drift, reduced gene flow and founder events. We investigated the pattern of polymorphism at the second exon of the Mhc‐DQA gene in island populations ofApodemus sylvaticusand in their mainland counterparts to investigate the pattern of MHC polymorphism in a phylogeographical context and to assess the impact of insularity on diversity at this locus.

Location Eight north Mediterranean populations ofApodemus sylvaticuswere studied, including five island populations (Majorca, Minorca, Porquerolles, Port‐Cros and Sicily) and three mainland populations.

Methods cDNA sequencing and nucleotide sequences analyses. Synonymous and non‐synonymous substitutions were examined at the PBR and non‐PBR sites. The DQA allelic distribution in populations was compared with the woodmouse phylogeography.

Results This study presents novel DQA alleles. High polymorphism of the DQA locus is recorded in natural populations ofA. sylvaticuswith 13 alleles being widely distributed irrespective of the geographical origin and palaeoclimatic history of populations. The DQA locus does not show the expected pattern for non‐synonymous substitutions at the PBR sites. However, island populations show a weak loss of polymorphism in comparison with their mainland counterparts.

Main conclusions The DQA locus in the woodmouse seems to be subject to weak selection and does not allow resolution of phylogeographical relationships among European woodmouse populations. The presence of at least three alleles in island populations and the maintenance of five alleles between the two European lineages over 1.5 Myr suggest that balancing selection may act within populations, and more precisely within island populations, to maintain genetic variability. This study shows that phylogeographical studies are a prerequisite for any genetic investigation of selected genes in natural populations.
Modelling geographical patterns in species richness using eigenvector‐based spatial filters
Authors: Diniz‐Filho José Alexandre Felizola , Bini Luis Mauricio
Published: February 2005

Aim  To test the mechanisms driving bird species richness at broad spatial scales using eigenvector‐based spatial filtering.

Location  South America.

Methods  An eigenvector‐based spatial filtering was applied to evaluate spatial patterns in South American bird species richness, taking into account spatial autocorrelation in the data. The method consists of using the geographical coordinates of a region, based on eigenanalyses of geographical distances, to establish a set of spatial filters (eigenvectors) expressing the spatial structure of the region at different spatial scales. These filters can then be used as predictors in multiple and partial regression analyses, taking into account spatial autocorrelation. Autocorrelation in filters and in the regression residuals can be used as stopping rules to define which filters will be used in the analyses.

Results  Environmental component alone explained 8% of variation in richness, whereas 77% of the variation could be attributed to an interaction between environment and geography expressed by the filters (which include mainly broad‐scale climatic factors). Regression coefficients of environmental component were highest for AET. These results were unbiased by short‐scale spatial autocorrelation. Also, there was a significant interaction between topographic heterogeneity and minimum temperature.

Conclusion  Eigenvector‐based spatial filtering is a simple and suitable statistical protocol that can be used to analyse patterns in species richness taking into account spatial autocorrelation at different spatial scales. The results for South American birds are consistent with the climatic hypothesis, in general, and energy hypothesis, in particular. Habitat heterogeneity also has a significant effect on variation in species richness in warm tropical regions.
Genetic modifiers of the Kvβ2‐null phenotype in mice
Authors: Connor J. X. , McCormack K. , Pletsch A. , Gaeta S. , Ganetzky B. , Chiu S.‐Y. , Messing A.
Published: February 2005

Shaker‐type potassium (K+) channels are composed of pore‐forming α subunits associated with cytoplasmic β subunits. Kvβ2 is the predominant Kvβ subunit in the mammalian nervous system, but its functions in vivo are not clear. Kvβ2‐null mice have been previously characterized in our laboratory as having reduced lifespans, cold swim‐induced tremors and occasional seizures, but no apparent defect in Kvα‐subunit trafficking. To test whether strain differences might influence the severity of this phenotype, we analyzed Kvβ2‐null mice in different strain backgrounds: 129/SvEv (129), C57BL/6J (B6) and two mixed B6/129 backgrounds. We found that strain differences significantly affected survival, body weight and thermoregulation in Kvβ2‐null mice. B6 nulls had a more severe phenotype than 129 nulls in these measures; this dramatic difference did not reflect alterations in seizure thresholds but may relate to strain differences we observed in cerebellar Kv1.2 expression. To specifically test whether Kvβ1 is a genetic modifier of the Kvβ2‐null phenotype, we generated Kvβ1.1‐deficient mice by gene targeting and bred them to Kvβ2‐null mice. Kvβ1.1/Kvβ2 double knockouts had significantly increased mortality compared with either single knockout but still maintained surface expression of Kv1.2, indicating that trafficking of this α subunit does not require either Kvβ subunit. Our results suggest that genetic differences between 129/SvEv and C57Bl/6J are key determinants of the severity of defects seen in Kvβ2‐null mice and that Kvβ1.1 is a specific although not strain‐dependent modifier.
Adenosine and ATP-sensitive potassium channels modulate dopamine release in the anoxic turtle (Trachemys scripta) striatum
Authors: Milton Sarah L. , Lutz Peter L.
Published: February 2005

Excessive dopamine (DA) is known to cause hypoxic/ischemic damage to mammalian brain. The freshwater turtle Trachemys scripta, however, maintains basal striatal DA levels in anoxia. We investigated DA balance during early anoxia when energy status in the turtle brain is compromised. The roles of ATP-sensitive potassium (KATP) channels and adenosine (AD) receptors were investigated as these factors affect DA balance in mammalian neurons. Striatal extracellular DA was determined by microdialysis with HPLC in the presence or absence of the specific DA transport blocker GBR-12909, the KATPblocker 2,3-butanedione monoxime, or the nonspecific AD receptor blocker theophylline. We found that in contrast to long-term anoxia, blocking DA reuptake did not significantly increase extracellular levels in 1-h anoxic turtles. Low DA levels in early anoxia were maintained instead by activation of KATPchannels and AD receptors. Blocking KATPresulted in a 227% increase in extracellular DA in 1-h anoxic turtles but had no effect after 4 h of anoxia. Similarly, blocking AD receptors increased DA during the first hour of anoxia but did not change DA levels at 4-h anoxia. Support for the role of KATPchannels in DA balance comes from normoxic animals treated with KATPopener; infusing diazoxide but not adenosine into the normoxic turtle striatum resulted in an immediate DA decrease to 14% of basal values within 1.5 h. Alternative strategies to maintain low extracellular levels may prevent catastrophic DA increases when intracellular energy is compromised while permitting the turtle to maintain a functional neuronal network during long-term anoxia.
Effect of chronic obstructive pulmonary disease on calcium pump ATPase expression in human diaphragm
Authors: Nguyen Taitan , Rubinstein Neal A. , Vijayasarathy Camasamudram , Rome Lawrence C. , Kaiser Larry R. , Shrager Joseph B. , Levine Sanford
Published: February 2005

We have previously demonstrated that human diaphragm remodeling elicited by severe chronic obstructive pulmonary disease (COPD) is characterized by a fast-to-slow myosin heavy chain isoform transformation. To test the hypothesis that COPD-induced diaphragm remodeling also elicits a fast-to-slow isoform shift in the sarcoendoplasmic reticulum Ca2+ATPase (SERCA), the other major ATPase in skeletal muscle, we obtained intraoperative biopsies of the costal diaphragm from 10 severe COPD patients and 10 control subjects. We then used isoform-specific monoclonal antibodies to characterize diaphragm fibers with respect to the expression of SERCA isoforms. Compared with control diaphragms, COPD diaphragms exhibited a 63% decrease in fibers expressing only fast SERCA (i.e., SERCA1; P < 0.001), a 190% increase in fibers containing both fast and slow SERCA isoforms ( P < 0.01), and a 19% increase ( P < 0.05) in fibers expressing only the slow SERCA isoform (i.e., SERCA2). Additionally, immunoblot experiments carried out on diaphragm homogenates indicated that COPD diaphragms expressed only one-third the SERCA1 content noted in control diaphragms; in contrast, COPD and control diaphragms did not differ with respect to SERCA2 content. The combination of these histological and immunoblot results is consistent with the hypothesis that diaphragm remodeling elicited by severe COPD is characterized by a fast-to-slow SERCA isoform transformation. Moreover, the combination of these SERCA data and our previously reported myosin heavy chain isoform data (Levine S, Nguyen T, Kaiser LR, Rubinstein NA, Maislin G, Gregory C, Rome LC, Dudley GA, Sieck GC, and Shrager JB. Am J Respir Crit Care Med 168: 706–713, 2003) suggests that diaphragm remodeling elicited by severe COPD should decrease ATP utilization by the diaphragm.
Heterogeneous limb vascular responsiveness to shear stimuli during dynamic exercise in humans
Authors: Wray D. Walter , Uberoi Abhimanyu , Lawrenson Lesley , Richardson Russell S.
Published: February 2005

Arm and leg vascular responsiveness to comparable shear stimuli during isolated dynamic exercise has not been assessed in humans. Consequently, six young cyclists performed incremental, intermittent handgrip exercise (arm) and knee-extensor exercise (leg) from 5 to 60% of maximal work rate (WR). Ultrasound Doppler measurements were taken in the brachial artery (BA), common femoral artery (CFA), and deep femoral artery (DFA) at rest and at each WR to assess diameter and sheer rate changes. Exercise at 60% maximum WR increased shear rate to the same degree in the CFA (314.3 ± 33.3 s−1) and BA (303.3 ± 26.3 s−1), but was significantly higher in the DFA (712.6 ± 88.3 s−1). Compared with rest, exercise at 60% maximum WR did not alter CFA vessel diameter, but increased BA diameter (0.42 ± 0.01 to 0.49 ± 0.01 cm) and DFA diameter (0.59 ± 0.05 to 0.64 ± 0.04 cm). These data from the DFA demonstrate for the first time a substantial improvement in vascular reactivity in a conduit vessel only slightly distal to the CFA. However, despite comparable dilation between the BA and DFA, the slope of the relationship between vessel diameter and shear rate was much greater in the arm (2.4 × 10−4± 4.6 × 10−5cm/s) than in either the DFA (8.9 × 10−5± 1.5 × 10−5cm/s) or CFA (2.1 × 10−5± 1.1 × 10−5cm/s). Together, these findings reveal a substantial heterogeneity in vascular responsiveness in the leg during dynamic exercise but demonstrate that conduit vessel dilation for a given change in shear rate is, nonetheless, reduced in the leg compared with the arm.
Role of Caspases in Death and Survival of the Plaque Macrophage
Authors: Nhan Thomas Q. , Liles W. Conrad , Schwartz Stephen M.
Published: February 2005

This review considers the role of macrophage cell death in formation of the necrotic core and in plaque progression, and lists many of the possible mediators of macrophage cell death. Among these, perhaps the most cited toxic agent is oxidized low-density lipoprotein (oxLDL). Whereas oxLDL can kill macrophage, and whereas the form of death is morphologically apoptotic, caspase inhibitors appear to be ineffective in preventing death. This finding is consistent with recent literature showing how the canonical caspase pathways are used for physiological cellular functions other than cell death. Plaque macrophages appear to be among the cells with this nonapoptotic signaling function for activated caspases. In many of the other cell types, caspase activation appears to play a critical role in cell differentiation. We discuss possible functions of plaque macrophage using the nondeath caspase pathway. Recent literature shows that physiological and developmental functions of many cell types require active caspases without progressing to cell death. We discuss the role of macrophage cell death in plaque progression, possible mediators of macrophage cell death, and the possible functions of plaque macrophage using the nondeath caspase pathway.
Angiotensin II and Aldosterone Regulate Gene Transcription Via Functional Mineralocortocoid Receptors in Human Coronary Artery Smooth Muscle Cells
Authors: Jaffe Iris Z. , Mendelsohn Michael E.
Published: February 2005

Inhibition or blockade of the angiotensin-aldosterone system consistently decreases ischemic cardiovascular events in clinical trials. The steroid hormone aldosterone acts by binding to the mineralocorticoid receptor (MR), a ligand activated transcription factor that is a member of the nuclear hormone receptor superfamily. MR binds and is activated by aldosterone and cortisol with equal affinity, but MR activation by cortisol is diminished in tissues that express the cortisol-inactivating enzyme 11-β-hydroxysteroid-dehydrogenase-2 (11βHSD2). Although previous studies support that the vasculature is a target tissue of aldosterone, MR-mediated gene expression in vascular cells has not been demonstrated or systematically explored. We investigated whether functional MR and 11βHSD2 are expressed in human blood vessels. Human coronary and aortic vascular smooth muscle cells (VSMCs) express mRNA and protein for both MR and 11βHSD2. The endogenous VSMC MR mediates aldosterone-dependent gene expression, which is blocked by the competitive MR antagonist spironolactone. Inhibition of 11βHSD2 in coronary artery VSMCs enhances gene transactivation by cortisol, supporting that the VSMC 11βHSD2 is functional. Angiotensin II also activates MR-mediated gene transcription in coronary artery VSMCs. Angiotensin II activation of MR-mediated gene expression is inhibited by both the AT1 receptor blocker losartan and by spironolactone, but not by aldosterone synthase inhibition. Microarray and quantitative RT-PCR experiments show that aldosterone activates expression of endogenous human coronary VSMC genes, including several involved in vascular fibrosis, inflammation, and calcification. These data support a new MR-dependent mechanism by which aldosterone and angiotensin II influence ischemic cardiovascular events, and suggest that ACE inhibitors and MR antagonists may decrease clinical ischemic events by inhibiting MR-dependent gene expression in vascular cells.
α
1
-Antichymotrypsin Gene (
SERPINA3
) A/T Polymorphism as a Risk Factor for Aneurysmal Subarachnoid Hemorrhage
Authors: Slowik Agnieszka , Borratynska Anna , Turaj Wojciech , Pera Joanna , Dziedzic Tomasz , Figlewicz Denise A. , Betlej Marek , Krzyszkowski Tadeusz , Czepko Ryszard , Szczudlik Andrzej
Published: February 2005

Background and Purpose—

The member 3 of clade A of serine proteinase inhibitors (SERPINA3), known previously as the α
1
-antichymotrypsin, is an acute phase protein, the levels of which increase in acute and chronic inflammation. The A/T polymorphism of the
SERPINA3
gene influences expression of SERPINA3 protein. SERPINA3 can be related to aneurysmal subarachnoid hemorrhage (SAH) by influencing inflammation or by regulating cathepsin G activity. We studied the significance of
SERPINA3
A/T polymorphism in patients with aneurysmal SAH compared with healthy controls.

Methods—

A total of 180 patients with aneurysmal SAH and 263 healthy controls were genotyped for the
SERPINA3
A/T polymorphism. Aneurysmal SAH was diagnosed by cranial computed tomography or lumbar puncture and digital subtraction angiography.
SERPINA3
polymorphism was detected by polymerase chain reaction amplification and restriction enzyme digestion.

Results—

The
SERPINA3
genotype distribution in patients with aneurysmal SAH (AA-29 16.1%; AT-108 60.0%; TT-43 23.9%) differed significantly from controls (AA-70 26.6%; AT-123 46.8%; TT-70 26.6%;
P
=0.009). A logistic regression model showed that the presence of genotype with T allele (AT+TT; odds ratio [OR], 2.01; 95% CI, 1.19 to 3.38;
P
=0.009) or AA genotype (OR, 0.49; 95% CI, 0.30 to 0.84;
P
=0.009) of the
SERPINA3
influences the risk for aneurysmal SAH independently from smoking, excessive alcohol consumption, and hypertension.

Conclusion—

The A/T polymorphism of
SERPINA3
gene is associated with the risk factor for aneurysmal SAH.
FLT3-ITD and tyrosine kinase domain mutants induce 2 distinct phenotypes in a murine bone marrow transplantation model
Authors: Grundler Rebekka , Miething Cornelius , Thiede Christian , Peschel Christian , Duyster Justus
Published: February 2005

Activating mutations of the Fms-like tyrosine kinase 3 (FLT3) receptor are the most common genetic alteration in acute myeloid leukemia (AML). Two distinct groups of FLT3 mutations are found: internal tandem duplications (ITDs) of the juxtamembrane region and point mutations within the tyrosine kinase domain (TKD). Recently, point mutations within the activation loop of FLT3 have also been described in childhood acute lymphoblastic leukemia (ALL). FLT3-ITD has been shown to induce a myeloproliferative syndrome in a murine bone marrow transplantation model. The phenotype of FLT3-TKD in mice has not yet been investigated. We transduced murine bone marrow with retrovirus-expressing FLT3-TKD mutants or FLT3-ITD and transplanted these cells into lethally irradiated mice. Mice that received a transplant of FLT3-ITD developed an oligoclonal myeloproliferative disease as previously described. In contrast, FLT3-TKD mutants induced an oligoclonal lymphoid disorder with longer latency and distinct hematologic manifestations: importantly, induction of the lymphoid phenotype was not due to a low number of transplanted cells. The lymphoid manifestation and longer latency of FLT3-TKD compared with FLT3-ITD mutants together with the lack of influence of FLT3-TKD mutations on the clinical outcome of patients with AML suggest differences in cell signaling between FLT3-TKD mutants and FLT3-ITDs. Indeed strong signal transducers and activators of transcription 5 (STAT5) activation could only be demonstrated for FLT3-ITDs. (Blood. 2005;105:4792-4799)
Contribution of gap junctional communication between tumor cells and astroglia to the invasion of the brain parenchyma by human glioblastomas
Authors: Oliveira Roxane , Christov Christo , Guillamo Jean Sébastien , de Boüard Sophie , Palfi Stéphane , Venance Laurent , Tardy Marcienne , Peschanski Marc
Published: February 2005

Background

Gliomas are "intraparenchymally metastatic" tumors, invading the brain in a non-destructive way that suggests cooperation between glioma cells and their environment. Recent studies using an engineered rodent C6 tumor cell line have pointed to mechanisms of invasion that involved gap junctional communication (GJC), with connexin 43 as a substrate. We explored whether this concept may have clinical relevance by analyzing the participation of GJC in human glioblastoma invasion.

Results

Three complementary in vitro assays were used: (i) seeding on collagen IV, to analyze homocellular interactions between tumor cells (ii) co-cultures with astrocytes, to study glioblastoma/astrocytes relationships and (iii) implantation into organotypic brain slice cultures, that mimic the three-dimensional parenchymal environment. Carbenoxolone, a potent blocker of GJC, inhibited cell migration in the two latter models. It paradoxically increased it in the first one. These results showed that homocellular interaction between tumor cells supports intercellular adhesion, whereas heterocellular glioblastoma/astrocytes interactions through functional GJC conversely support tumor cell migration. As demonstrated for the rodent cell line, connexin 43 may be responsible for this heterocellular functional coupling. Its levels of expression, high in astrocytes, correlated positively with invasiveness in biopsied tumors.

Conclusions

our results underscore the potential clinical relevance of the concept put forward by other authors based on experiments with a rodent cell line, that glioblastoma cells use astrocytes as a substrate for their migration by subverting communication through connexin 43-dependent gap junctions.
Novel hepatocyte growth factor (HGF) binding domains on fibronectin and vitronectin coordinate a distinct and amplified Met-integrin induced signalling pathway in endothelial cells
Authors: Rahman Salman , Patel Yatin , Murray Jacqueline , Patel Kirti V , Sumathipala Rushika , Sobel Michael , Wijelath Errol S
Published: February 2005

Background

The growth of new blood vessels in adult life requires the initiation of endothelial cell migration and proliferation from pre-existing vessels in addition to the recruitment and differentiation of circulating endothelial progenitor cells. Signals emanating from growth factors and the extracellular matrix are important in regulating these processes.

Results

Here we report that fibronectin (FN) and vitronectin (VN) modulate the responses of endothelial cells to HGF (Scatter Factor), an important pro-angiogenic mediator. Novel binding sites for HGF were identified on both FN and VN that generate molecular complexes with enhanced biological activity and these were identified in the supernatants of degranulated platelet suspensions implicating their release and formation in vivo. In the absence of co-stimulation with an ECM glycoprotein, HGF could not promote endothelial cell migration but retained the capacity to induce a proliferative response utilising the Map kinase pathway. Through promoting Met-Integrin association, HGF-FN and HGF-VN complexes coordinated and enhanced endothelial cell migration through activation of the PI-3 kinase pathway involving a Ras-dependent mechanism whereas a Ras-independent and attenuated migratory response was promoted by co-stimulation of cells with HGF and a non-binding partner ECM glycoprotein such as collagen-1.

Conclusions

These studies identify a novel mechanism and pathway of HGF signalling in endothelial cells involving cooperation between Met and integrins in a Ras dependent manner. These findings have implications for the regulation of neovascularization in both health and disease.
An interactional network of genes involved in chitin synthesis in Saccharomyces cerevisiae
Authors: Lesage Guillaume , Shapiro Jesse , Specht Charles A , Sdicu Anne-Marie , Ménard Patrice , Hussein Shamiza , Tong Amy Hin Yan , Boone Charles , Bussey Howard
Published: February 2005

Background

In S. cerevisiae the β-1,4-linked N-acetylglucosamine polymer, chitin, is synthesized by a family of 3 specialized but interacting chitin synthases encoded by CHS1, CHS2 and CHS3. Chs2p makes chitin in the primary septum, while Chs3p makes chitin in the lateral cell wall and in the bud neck, and can partially compensate for the lack of Chs2p. Chs3p requires a pathway of Bni4p, Chs4p, Chs5p, Chs6p and Chs7p for its localization and activity. Chs1p is thought to have a septum repair function after cell separation. To further explore interactions in the chitin synthase family and to find processes buffering chitin synthesis, we compiled a genetic interaction network of genes showing synthetic interactions with CHS1, CHS3 and genes involved in Chs3p localization and function and made a phenotypic analysis of their mutants.

Results

Using deletion mutants in CHS1, CHS3, CHS4, CHS5, CHS6, CHS7 and BNI4 in a synthetic genetic array analysis we assembled a network of 316 interactions among 163 genes. The interaction network with CHS3, CHS4, CHS5, CHS6, CHS7 or BNI4 forms a dense neighborhood, with many genes functioning in cell wall assembly or polarized secretion. Chitin levels were altered in 54 of the mutants in individually deleted genes, indicating a functional relationship between them and chitin synthesis. 32 of these mutants triggered the chitin stress response, with elevated chitin levels and a dependence on CHS3. A large fraction of the CHS1-interaction set was distinct from that of the CHS3 network, indicating broad roles for Chs1p in buffering both Chs2p function and more global cell wall robustness.

Conclusion

Based on their interaction patterns and chitin levels we group interacting mutants into functional categories. Genes interacting with CHS3 are involved in the amelioration of cell wall defects and in septum or bud neck chitin synthesis, and we newly assign a number of genes to these functions. Our genetic analysis of genes not interacting with CHS3 indicate expanded roles for Chs4p, Chs5p and Chs6p in secretory protein trafficking and of Bni4p in bud neck organization.
Identification of functional SNPs in the 5-prime flanking sequences of human genes
Authors: Mottagui-Tabar Salim , Faghihi Mohammad A , Mizuno Yosuke , Engström Pär G , Lenhard Boris , Wasserman Wyeth W , Wahlestedt Claes
Published: February 2005

Background

Over 4 million single nucleotide polymorphisms (SNPs) are currently reported to exist within the human genome. Only a small fraction of these SNPs alter gene function or expression, and therefore might be associated with a cell phenotype. These functional SNPs are consequently important in understanding human health. Information related to functional SNPs in candidate disease genes is critical for cost effective genetic association studies, which attempt to understand the genetics of complex diseases like diabetes, Alzheimer's, etc. Robust methods for the identification of functional SNPs are therefore crucial. We report one such experimental approach.

Results

Sequence conserved between mouse and human genomes, within 5 kilobases of the 5-prime end of 176 GPCR genes, were screened for SNPs. Sequences flanking these SNPs were scored for transcription factor binding sites. Allelic pairs resulting in a significant score difference were predicted to influence the binding of transcription factors (TFs). Ten such SNPs were selected for mobility shift assays (EMSA), resulting in 7 of them exhibiting a reproducible shift. The full-length promoter regions with 4 of the 7 SNPs were cloned in a Luciferase based plasmid reporter system. Two out of the 4 SNPs exhibited differential promoter activity in several human cell lines.

Conclusions

We propose a method for effective selection of functional, regulatory SNPs that are located in evolutionary conserved 5-prime flanking regions (5'-FR) regions of human genes and influence the activity of the transcriptional regulatory region. Some SNPs behave differently in different cell types.
The PECACE domain: a new family of enzymes with potential peptidoglycan cleavage activity in Gram-positive bacteria
Authors: Pagliero Estelle , Dideberg Otto , Vernet Thierry , Di Guilmi Anne Marie
Published: February 2005

Background

The metabolism of bacterial peptidoglycan is a dynamic process, synthases and cleavage enzymes are functionally coordinated. Lytic Transglycosylase enzymes (LT) are part of multienzyme complexes which regulate bacterial division and elongation. LTs are also involved in peptidoglycan turnover and in macromolecular transport systems. Despite their central importance, no LTs have been identified in the human pathogen Streptococcus pneumoniae. We report the identification of the first putative LT enzyme in S. pneumoniae and discuss its role in pneumococcal peptidoglycan metabolism.

Results

Homology searches of the pneumococcal genome allowed the identification of a new domain putatively involved in peptidoglycan cleavage (PECACE, PE ptidoglycan CA rbohydrate C leavage E nzyme). This sequence has been found exclusively in Gram-positive bacteria and gene clusters containing pecace are conserved among Streptococcal species. The PECACE domain is, in some instances, found in association with other domains known to catalyze peptidoglycan hydrolysis.

Conclusions

A new domain, PECACE, putatively involved in peptidoglycan hydrolysis has been identified in S. pneumoniae. The probable enzymatic activity deduced from the detailed analysis of the amino acid sequence suggests that the PECACE domain may proceed through a LT-type or goose lyzosyme-type cleavage mechanism. The PECACE function may differ largely from the other hydrolases already identified in the pneumococcus: LytA, LytB, LytC, CBPD and PcsB. The multimodular architecture of proteins containing the PECACE domain is another example of the many activities harbored by peptidoglycan hydrolases, which is probably required for the regulation of peptidoglycan metabolism. The release of new bacterial genomes sequences will probably add new members to the five groups identified so far in this work, and new groups could also emerge. Conversely, the functional characterization of the unknown domains mentioned in this work can now become easier, since bacterial peptidoglycan is proposed to be the substrate.
Antiglucocorticoid RU38486 reduces net protein catabolism in experimental acute renal failure
Authors: Mondry Adrian
Published: February 2005

Background

In acute renal failure, a pronounced net protein catabolism occurs that has long been associated with corticoid action. By competitively blocking the glucocorticoid receptor with the potent antiglucocorticoid RU 38486, the present study addressed the question to what extent does corticoid action specific to uremia cause the observed muscle degradation, and does inhibition of glucocorticoid action reduce the protein wasting?

Methods

RU 38486 was administered in a dose of 50 mg/kg/24 h for 48 h after operation to fasted bilaterally nephrectomized (BNX) male adult Wistar rats and sham operated (SHAM) controls. Protein turnover was evaluated by high performance liquid chromatography (HPLC) of amino acid efflux in sera from isolated perfused hindquarters of animals treated with RU 38486 versus untreated controls.

Results

Administration of RU 38486 reduces the total amino acid efflux (TAAE) by 18.6% in SHAM and 15.6% in BNX and efflux of the indicator of net protein turnover, phenylalanine (Phe) by 33.3% in SHAM and 13% in BNX animals as compared to the equally operated, but untreated animals. However, the significantly higher protein degradation observed in BNX (0.6 ± 0.2 nmol/min/g muscle) versus SHAM (0.2 ± 0.1 nmol/min/g muscle) rats, as demonstrated by the marker of myofribrillar proteolytic rate, 3-Methylhistidine (3 MH) remains unaffected by administration of RU 38486 (0.5 ± 0.1 v. 0.2 ± 0.1 nmol/min/g muscle in BNX v. SHAM).

Conclusion

RU 38486 does not act on changes of muscular protein turnover specific to uremia but reduces the effect of stress- stimulated elevated corticosterone secretion arising from surgery and fasting. A potentially beneficial effect against stress- induced catabolism in severe illness can be postulated that merits further study.
The pre-vaccination regional epidemiological landscape of measles in Italy: contact patterns, effort needed for eradication, and comparison with other regions of Europe
Authors: Manfredi Piero , Cleur Eugene M , Williams John R , Salmaso Stefania , Atti Marta Ciofi degli
Published: February 2005

Background

Strong regional heterogeneity and generally sub-optimal rates of measles vaccination in Italy have, to date, hampered attainment of WHO targets for measles elimination, and have generated the need for the new Italian National Measles Elimination Plan. Crucial to success of the plan is the identification of intervention priorities based upon a clear picture of the regional epidemiology of measles derived from the use of data to estimate basic parameters. Previous estimates of measles force of infection for Italy have appeared anomalously low. It has been argued elsewhere that this results from Italian selective under-reporting by age of cases and that the true measles force of infection in Italy is probably similar to that of other European countries. A deeper examination of the evidence for this conjecture is undertaken in the present paper.

Methods

Using monthly regional case notifications data from 1949 to the start of vaccination in 1976 and notifications by age from 1971–76, summary equilibrium parameters (force of infection (FOI), basic reproductive ratio (R0) and critical vaccination coverage (p
c
)) are calculated for each region and for each of 5 plausible contact patterns. An analysis of the spectra of incidence profiles is also carried out. Finally a transmission dynamics model is employed to explore the correspondence between projections using different estimates of force of infection and data on seroprevalence in Italy.

Results

FOI estimates are lower than comparable European FOIs and there is substantial regional heterogeneity in basic reproductive ratios; certain patterns of contact matrices are demonstrated to be unfeasible. Most regions show evidence of 3-year epidemic cycles or longer, and compared with England & Wales there appears to be little synchronisation between regions. Modelling results suggest that the lower FOI estimated from corrected aggregate national data matches serological data more closely than that estimated from typical European data.

Conclusion

Results suggest forces of infection in Italy, though everywhere remaining below the typical European level, are historically higher in the South where currently vaccination coverage is lowest. There appears to be little evidence to support the suggestion that a higher true force of infection is masked by age bias in reporting.
Molecular strategies to inhibit HIV-1 replication
Authors: Nielsen Morten Hjuler , Pedersen Finn Skou , Kjems Jørgen
Published: February 2005

The human immunodeficiency virus type 1 (HIV-1) is the primary cause of the acquired immunodeficiency syndrome (AIDS), which is a slow, progressive and degenerative disease of the human immune system. The pathogenesis of HIV-1 is complex and characterized by the interplay of both viral and host factors. An intense global research effort into understanding the individual steps of the viral replication cycle and the dynamics during an infection has inspired researchers in the development of a wide spectrum of antiviral strategies. Practically every stage in the viral life cycle and every viral gene product is a potential target. In addition, several strategies are targeting host proteins that play an essential role in the viral life cycle. This review summarizes the main genetic approaches taken in such antiviral strategies.
Anal screening cytology
Authors: Leiman Gladwyn
Published: February 2005

This issue of CytoJournal contains an article on screening for anal intraepithelial neoplasia in high-risk male patients. This accompanying Editorial focuses on current understanding of this relatively new disease entity, with insights as to the potential role of screening cytopathology in the epidemiology, pathophysiology and clinical management of this HIV and HPV related anal lesion, which predominates in male patients living long-term with AIDS. Mention is made of techniques of obtaining samples, methods of preparation, and morphologic classification. Issues of anoscopic confirmation, as well as topical and surgical management are emphasized. The similarity of initial experiences in anal screening to problems encountered early in cervical cancer screening programs several decades ago, are highlighted.