bluuebunny/crossref_metadata_2025 huggingface dataset:
Decreased MT1 and MT2 melatonin receptor expression in extrapineal tissues of the rat during physiological aging
Authors: Sánchez‐Hidalgo Marina , Guerrero Montávez Juan Miguel , Carrascosa‐Salmoral María del Pilar , Naranjo Gutierrez María del Carmen , Lardone Patricia Judith , De La Lastra Romero Catalina Alarcón
Published: May 2008

Abstract: Aging is a complex process associated with a diminished ability to respond to stress, a progressive increase in free radical generation and a decline in immune function. Melatonin, a molecule with a great functional versatility exerts anti‐oxidant, oncostatic, immunomodulatory, and anti‐aging properties. Melatonin levels drop during aging and it has been speculated that the loss of melatonin may accelerate aging. This study was designed to elucidate whether aging involves responsiveness to reduced melatonin. Melatonin membrane receptor (MT1 and MT2) expression and MT1 protein expression were analyzed in extrapineal tissues (thymus, spleen, liver, kidney, and heart) of 3‐ and 12‐month‐old rats using real time polymerase chain reaction and western blotting analysis. Moreover, melatonin in tissues was measured by high performance liquid chromatography. We report for the first time, an age‐related reduction in mRNA MT1 and MT2 expression levels as well as MT1 protein expression in all tissues tested except the thymus, where surprisingly, both melatonin receptor levels were significantly higher in 12‐month‐old rats and MT1 protein expression maintained unchanged with age. Diminished melatonin concentrations were measured in spleen, liver, and heart during aging. As a conclusion, physiological aging seems to exert responsiveness to melatonin and consequently, the loss of this potent anti‐oxidant may contribute to onset of aging.
Peroxisome Fission in Hansenula polymorpha Requires Mdv1 and Fis1, Two Proteins Also Involved in Mitochondrial Fission
Authors: Nagotu Shirisha , Krikken Arjen M. , Otzen Marleen , Kiel Jan A. K. W. , Veenhuis Marten , Van Der Klei Ida J.
Published: May 2008

We show that Mdv1 and Caf4, two components of the mitochondrial fission machinery in Saccharomyces cerevisiae, also function in peroxisome proliferation. Deletion of MDV1, CAF4 or both, however, had only a minor effect on peroxisome numbers at peroxisome‐inducing growth conditions, most likely related to the fact that Vps1 – and not Dnm1 – is the key player in peroxisome fission in this organism. In contrast, in Hansenula polymorpha, which has only a Dnm1‐dependent peroxisome fission machinery, deletion of MDV1 led to a drastic reduction of peroxisome numbers. This phenotype was accompanied by a strong defect in mitochondrial fission. The MDV1 paralog CAF4 is absent in H. polymorpha. In wild‐type H. polymorpha, cells Dnm1–mCherry and green fluorescent protein (GFP)–Mdv1 colocalize in spots that associate with both peroxisomes and mitochondria. Furthermore, Fis1 is essential to recruit Mdv1 to the peroxisomal and mitochondrial membrane. However, formation of GFP–Mdv1 spots – and related to this normal organelle fission – is strictly dependent on the presence of Dnm1. In dnm1 cells, GFP–Mdv1 is dispersed over the surface of peroxisomes and mitochondria. Also, in H. polymorpha mdv1 or fis1 cells, the number of Dnm1–GFP spots is strongly reduced. These spots still associate to organelles but are functionally inactive.
The Plant ER–Golgi Interface
Authors: Hawes Chris , Osterrieder Anne , Hummel Eric , Sparkes Imogen
Published: May 2008

The interface between the endoplasmic reticulum (ER) and the Golgi apparatus is a critical junction in the secretory pathway mediating the transport of both soluble and membrane cargo between the two organelles. Such transport can be bidirectional and is mediated by coated membranes. In this review, we consider the organization and dynamics of this interface in plant cells, the putative structure of which has caused some controversy in the literature, and we speculate on the stages of Golgi biogenesis from the ER and the role of the Golgi and ER on each other’s motility.
Mammalian xanthine oxidoreductase – mechanism of transition from xanthine dehydrogenase to xanthine oxidase
Authors: Nishino Tomoko , Okamoto Ken , Eger Bryan T. , Pai Emil F. , Nishino Takeshi
Published: May 2008

Reactive oxygen species are generated by various biological systems, including NADPH oxidases, xanthine oxidoreductase, and mitochondrial respiratory enzymes, and contribute to many physiological and pathological phenomena. Mammalian xanthine dehydrogenase (XDH) can be converted to xanthine oxidase (XO), which produces both superoxide anion and hydrogen peroxide. Recent X‐ray crystallographic and site‐directed mutagenesis studies have revealed a highly sophisticated mechanism of conversion from XDH to XO, suggesting that the conversion is not a simple artefact, but rather has a function in mammalian organisms. Furthermore, this transition seems to involve a thermodynamic equilibrium between XDH and XO; disulfide bond formation or proteolysis can then lock the enzyme in the XO form. In this review, we focus on recent advances in our understanding of the mechanism of conversion from XDH to XO.
Relationships between soil organic matter and forest productivity in western Oregon and Washington
Authors: Edmonds R.L. , Chappell H.N.
Published: May 2008

Mineral soil and forest floor C and N contents were determined in 154 Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) and western hemlock (Tsugaheterophylla (Raf.) Sarg.) stands in western Oregon and Washington ranging in age from 16 to 64 years. Relationships between site index and mineral soil and forest floor C, N, and C/N ratios were examined. Douglas-fir data were analyzed by geographic province (Puget Sound, Washington Cascades, Oregon Cascades, coastal Washington, coastal Oregon, and southwest Oregon). Average mineral soil C in Douglas-fir stands ranged from 102 Mg/ha to 177 Mg/ha in Puget Sound and Washington Cascades provinces, respectively. Soil N ranged from 3708 kg/ha in Puget Sound province to 9268 kg/ha in the Washington Cascade province. Western hemlock data were analyzed in three provinces (Washington Cascades, coastal Washington, and coastal Oregon). Average mineral soil C in western hemlock stands ranged from 241 Mg/ha in the Washington Cascades to 309 Mg/ha in coastal Washington and was higher than Douglas-fir mineral soil C. Western hemlock mineral soil N was also higher than Douglas-fir mineral soil N ranging from 10 495 kg/ha in the Washington Cascades to 15 216 kg/ha in coastal Oregon. Forest floor C and N contents were also higher in western hemlock than Douglas-fir stands. Nonlinear regression analysis revealed a weak positive relationship between site index and total mineral soil C in Douglas-fir (r2 = 0.19). A similar relationship was observed between Douglas-fir site index and total soil N (r2 = 0.19). Relationships were weak because of the large variability in mineral soil C and N within as well as across provinces. Maximum Douglas-fir site indexes occurred across a broad plateau of mineral soil and forest floor C/N ratios ranging from 15–25 and 35–45, respectively. Minimum site indexes also occurred in these C/N ranges. No increase in Douglas-fir productivity occurred above mineral soil C levels of 125 Mg/ha. There were no relationships between site index and mineral soil C and N or C/N ratios in western hemlock stands.
The Silvicultural Management System in temperate and boreal forests: A case history of the Hokkaido Tokyo University Forest
Authors: Watanabe Sadamoto , Sasaki Satohiko
Published: May 2008

Forest managers need new approaches for maintaining high stand volumes while keeping forests continuously productive and economically profitable. The Silvicultural Management System (SMS) accomplishes these objectives by increasing large-sized trees for periodic harvest, and continuously maintaining stand volumes at their highest possible levels. This system takes advantage of the diversity in growth, vigor, and longevity of dominant trees from a wide range of tree species found in natural forest ecosystems. Under the SMS developed at the Tokyo University Forest in Hokkaido, 13–17% of the stand volume is harvested at a cutting cycle of 8–10 years by removing the oldest mature trees. Residual stand volumes are maintained at about 70–80% of the levels found in natural old-growth stands. This removal of the oldest trees keeps the stands in a continuously healthy and productive state. The cutting level is planned to ensure a sufficient harvest to cover the construction costs of a necessary high-density forest road network that provides the great logging efficiency and limited maximum yarding distances. This form of selection cutting has proven to be highly productive, surpassing even the production realized under clear cutting. Well-managed cuttings under SMS improve the quality and quantity of the timber resource, with particular emphasis upon premium-quality hardwoods. Guidelines are given for individual tree selection cutting to produce premium-quality hardwoods, and based upon a high-density forest road network. The value of this high-quality timber makes such low-volume logging operations profitable. The SMS also maintains a favorable forest ecosystem for diverse wildlife and flora, and several endangered or threatened wildlife species that depend upon less dense mature forests occur in SMS forests. Managed forests with high-volume stocking also serve as an effective carbon dioxide sink.
Genetic variation in tree structure and its relation to size in Douglas-fir. I. Biomass partitioning, foliage efficiency, stem form, and wood density
Authors: St.Clair J. B.
Published: May 2008

Genetic variation and covariation among traits of tree size and structure were assessed in an 18-year-old Douglas-fir (Pseudotsugamenziesii var. menziesii (Mirb.) Franco) genetic test in the Coast Range of Oregon. Considerable genetic variation was found in size, biomass partitioning, and wood density, and genetic gains may be expected from selection and breeding of desirable genotypes. Estimates of heritability for partitioning traits, including harvest index, were particularly high. Foliage efficiency (stem increment per unit leaf area) was strongly correlated with harvest index and may represent an alternative measure of partitioning to the stem. Estimates of foliage efficiency where leaf area was estimated based on stem diameter or sapwood area were unrelated to foliage efficiency where leaf area was measured directly. Strong negative genetic correlations were found between harvest index and stem size, and between wood density and stem size. Achieving simultaneous genetic gain in stem size and either harvest index or wood density would be difficult.
In vitro micropropagation of Afghan pine
Authors: Sen S. , Magallanes-Cedeno M.E. , Kamps R.H. , McKinley C.R. , Newton R.J.
Published: May 2008

Clonal propagation by tissue culture of Afghan pine (Pinuseldarica Medw.) could be useful for improving Christmas tree production and afforestation of semiarid lands in North America. The objectives were (i) to develop organogenesis procedures for clonal propagation and (ii) to evaluate plantlet performance in the field. Shoot production from cotyledon explants was accomplished on solid Shenk and Hildebrandt medium amended with kinetin (11 μM) and benzyladenine (11 μM). Over 100 shoots per clone were obtained with this method. Spontaneous rooting was prevalent in some of the induced shoots. Shoots without root primordia were induced to form roots with naphthalene acetic acid (5 μM), indole butyric acid (10 μM), and benzyladenine (0.22 μM) in 1/2 strength Shenk and Hildebrandt medium. The rate of plantlet elongation in the field was similar to that of seedlings; however, survival of plantlets was lower than that of seedlings. The lower survival of plantlets was directly related to their smaller size at the time of planting. Organogenesis appears to be a very suitable method for mass micropropagation of this environmentally and economically useful tree.
Economic trade-offs of managing forests for timber production and vegetative diversity
Authors: Holland David N. , Lilieholm Robert J. , Roberts David W. , Gilless J. Keith
Published: May 2008

Three indices of forest stand structural and compositional diversity were incorporated into a linear programming timber harvest scheduling model to examine the trade-offs between managing stands for timber production and biodiversity objectives. The indices, based on Shannon's diversity index, characterized stand species diversity, basal area diversity, and vertical crown diversity. While harvest-level objectives were often compatible with the maintenance of vegetative diversity, the maximization of present net value was accompanied by substantial reductions in all three measures of diversity.
Economic losses resulting from ambrosia beetle infestation of sawlogs in coastal British Columbia, Canada
Authors: Orbay L. , McLean J. A. , Sauder B.J. , Cottell P.L.
Published: May 2008

Estimates of ambrosia beetle damage on 10 log grades, commonly used in sawmills of coastal British Columbia, were determined by the sawmill team of an Ambrosia Beetle Task Force during 1990–1992. A total of 417 ambrosia beetle attacked logs were evaluated in eight cooperating sawmills. Test logs were processed into lumber products, graded, and valued. Estimates of dollar loss per cubic metre for various log diameter classes were made. The average losses for the 10 log grades with respect to grade of lumber, with and without pinholes, ranged from $3.27 to $77.40/m3 of log. Changes in sawing patterns as a result of ambrosia beetle infestation were also assessed. The loss of deep clear potential on high-grade logs increased value losses by 57%. One third of large pulp logs were sawn for lumber. Ambrosia beetle infestation of sawn large pulp logs resulted in $19.20/m3 degrade loss.
A simple volume estimation system and its application to three coniferous species
Authors: Yamamoto Kazukiyo
Published: May 2008

A simple system for the estimation of stem volume is presented based on the compatible stem profile and volume equations. This system can directly predict the stem volume above breast height from measurements of stem diameter at breast height and at an another point along the upper stem, and does not require any sample data for determining a parameter of volume equation. In comparison with the prediction accuracy of existing volume equations from the literature, using data from Cryptomeriajaponica D. Don, Chamaecyparisobtsusa Endl., and Pseudotsugamenziesii (Mirb.) Franco, this system has the advantage of reducing prediction error.
Expression of human endothelin-converting enzyme isoforms: role of angiotensin IIThis article is one of a selection of papers published in the special issue (part 1 of 2) on Forefronts in Endothelin.
Authors: Goettsch W. , Schubert A. , Morawietz H.
Published: May 2008

A key step in endothelin-1 (ET-1) synthesis is the proteolytic cleavage of big ET-1 by the endothelin-converting enzyme-1 (ECE-1). Four alternatively spliced isoforms, ECE-1a to ECE-1d, have been discovered; however, regulation of the expression of specific ECE-1 isoforms is not well understood. Therefore, we stimulated primary human umbilical vein endothelial cells (HUVECs) with angiotensin II (Ang II). Furthermore, expression of ECE-1 isoforms was determined in internal mammary arteries of patients undergoing coronary artery bypass grafting surgery. Patients had received one of 4 therapies: angiotensin-converting enzyme inhibitors (ACE-I), Ang II type 1 receptor blockers (ARB), HMG-CoA reductase inhibitors (statins), and a control group that had received neither ACE-I, ARB (that is, treatment not interfering in the renin–angiotensin system), nor statins. Under control conditions, ECE-1a is the dominant isoform in HUVECs (4.5 ± 2.8 amol/μg RNA), followed by ECE-1c (2.7 ± 1.0 amol/μg), ECE-1d (0.49 ± 0.17 amol/μg), and ECE-1b (0.17 ± 0.04 amol/μg). Stimulation with Ang II did not change the ECE-1 expression pattern or the ET-1 release. We found that ECE-1 mRNA expression was higher in patients treated with statins than in patients treated with ARB therapy (5.8 ± 0.76 RU versus 3.0 ± 0.4 RU), mainly attributed to ECE-1a. In addition, ECE-1a mRNA expression was higher in patients receiving ACE-I therapy than in patients receiving ARB therapy (1.68 ± 0.27 RU versus 0.83 ± 0.07 RU). We conclude that ECE-1a is the major ECE-1 isoform in primary human endothelial cells. Its expression in internal mammary arteries can be regulated by statin therapy and differs between patients with ACE-I and ARB therapy.
Role of hypoxia in the regulation of periovulatory EDN2 expression in the mouseThis article is one of a selection of papers published in the special issue (part 1 of 2) on Forefronts in Endothelin.
Authors: Na Giyoun , Bridges Phillip J. , Koo Yongbum , Ko CheMyong
Published: May 2008

We have previously proposed endothelin-2 (EDN2) as a granulosa cell-derived contractile signal that facilitates ovulation. Spatially, Edn2 mRNA expression is restricted to granulosa cells of periovulatory follicles. Temporally, mRNA for this contractile peptide is expressed immediately before follicle rupture. The primary objective of this study was to test the hypothesis that hypoxia mediates EDN2 expression in granulosa cells at ovulation, and if it does, to determine the region within the promoter responsible for this effect. To determine the effect of hypoxia on mRNA expression, immature mice were treated with 5 IU of PMSG followed 48 h later by 5 IU of human chorionic gonadotropin (hCG). Granulosa cells were isolated at 9 h after hCG, cultured under normal or hypoxic conditions, and the expression level of mRNA was compared. mRNA expression was increased when granulosa cells were cultured in a hypoxic environment (p < 0.05). Subsequent promoter analysis found that the 5′ upstream region of the EDN2 promoter (between –1894 bp and –1407 bp) was responsible for hypoxia-mediated changes in EDN2 expression. This promoter region contains multiple sites for potential transcriptional regulation, including that by hypoxia-inducible factor 1 (HIF-1, ACGTG) at –1297 bp. The second objective of this study was to determine whether the progesterone receptor (PR) or cyclooxygenase-2 (COX-2), two key regulators of periovulatory events, controlled EDN2 expression. To accomplish this, gonadotropin-primed mice were treated with RU-486 or indomethacin and expression of mRNA for Edn2 was determined in ovaries collected at 12 h after hCG. Treatment with RU-486 or indomethacin did not affect expression of mRNA for Edn2 (p > 0.05). Taken together, we believe that hypoxia, but not the PR or COX-2, regulate gonadotropin-induced EDN2 expression in the periovulatory follicle.
Role of the renin–angiotensin–aldosterone system in collecting duct-derived endothelin-1 regulation of blood pressureThis article is one of a selection of papers published in the special issue (part 1 of 2) on Forefronts in Endothelin.
Authors: Ge Yuqiang , Huang Yufeng , Kohan Donald E.
Published: May 2008

Renal collecting duct (CD)-specific knockout of endothelin-1 (ET-1) causes hypertension and impaired Na excretion. A previous study noted failure to suppress the renin–angiotensin–aldosterone axis in these knockout (KO) mice, hence the current investigation was undertaken to examine the role of this system in CD ET-1 KO. Renal renin content was similar in kidneys from CD ET-1 KO and control mice during normal Na intake; high-Na intake suppressed renal renin content to a similar degree in KO and control. Plasma renin concentrations paralleled changes in renal renin content. Valsartan, an angiotensin receptor blocker (ARB), abolished the hypertension in CD ET-1 KO mice during normal Na intake. High-Na intake + ARB treatment increased blood pressure in CD ET-1 KO, but not in controls. High-Na intake was associated with reduced Na excretion in CD ET-1 KO animals, but no changes in water excretion or creatinine clearance were noted. Spironolactone, an aldosterone antagonist, also normalized blood pressure in CD ET-1 KO mice during normal Na intake, whereas high-Na intake + spironolactone raised blood pressure only in CD ET-1 KO animals. In summary, hypertension in CD ET-1 KO is partly due to angiotensin II and aldosterone. We speculate that CD-derived ET-1 may regulate, via a novel pathway, renal renin production.
ETA-receptor blockade impairs vasoconstriction after hemorrhage in xenon-anesthetized dogs treated with an AT1-receptor antagonistThis article is one of a selection of papers published in the special issue (part 1 of 2) on Forefronts in Endothelin.
Authors: Höhne Claudia , Francis Roland C.E. , Pickerodt Philipp , Klein Adrian , Kaisers Udo , Boemke Willehad
Published: May 2008

The effects of endothelin receptor subtype A (ETA) blockade on hemodynamics and hormonal adaptation during hemorrhage were studied in xenon/remifentanil-anesthetized dogs (n = 6) pretreated with an angiotensin II type 1 (AT1)-receptor blocker. Controls: after a baseline awake period, anesthesia was induced in the dogs with propofol and maintained with xenon/remifentanil (baseline anesthesia). Sixty minutes later, 20 mL·kg–1 of blood was withdrawn within 5 min and the dogs observed for another hour (hemorrhage). AT1 group followed the same protocol as controls except the AT1-receptor blocker losartan (i.v. 100 μg·kg–1·min–1) was started at the beginning of the experiment. AT1+ETA group was the same as AT1 group but with the addition of the ETA-receptor blocker atrasentan (i.v. 1 mg·kg–1, then 0.01 mg·kg–1·min–1). In controls, mean arterial pressure (MAP) remained unchanged during baseline anesthesia, whereas systemic vascular resistance (SVR) increased from 3282 ± 281 to 7321 ± 803 dyn·s·cm–5, heart rate (HR) decreased from 86 ± 4 to 40 ± 3 beats·min–1, and cardiac output (CO) decreased from 2.3 ± 0.2 to 0.9 ± 0.1 L·min–1 (p < 0.05), with no further changes after hemorrhage. In AT1-inhibited dogs, MAP (71 ± 6 mm Hg) and SVR (5939 ± 611 dyn·s·cm–5) were lower during baseline anesthesia and after hemorrhage, but greater than those in AT1+ETA (66 ± 7 mm Hg, 5034 ± 658 dyn·s·cm–5) (p < 0.05). HR and CO were not different between groups. Plasma concentration of vasopressin was highest with AT1+ETA inhibition after hemorrhage. Combined AT1+ETA-receptor blockade impaired vasoconstriction more than did AT1-receptor blockade alone, both during baseline xenon anesthesia and after hemorrhage. Even a large increase in vasoconstrictor hormones could not prevent the decrease in blood pressure and the smaller increase in SVR. Thus, endothelin is an important vasoconstrictor during hemorrhage, and both endothelin and angiotensin II are essential hormones for cardiovascular stabilization after hemorrhage.
Nonselective ETA/ETB-receptor blockade increases systemic blood pressure of Bio 14.6 cardiomyopathic hamstersThis article is one of a selection of papers published in the special issue (part 1 of 2) on Forefronts in Endothelin.
Authors: Honoré Jean-Claude , Carrier Émilie , Fecteau Marie-Hélène , Tirapelli Carlos R. , Bkaily Ghassan , D’Orleans-Juste Pedro
Published: May 2008

To examine the role of endothelin ETAand ETBreceptors in congestive heart failure due to cardiomyopathy, the effect of chronic treatment with selective ETA- and ETB-receptor antagonists (atrasentan and A-192621, respectively), alone and in combination, was assessed on functional and biochemical parameters of 52-week-old Bio 14.6 cardiomyopathic hamsters. Compared with control animals, cardiomyopathic hamsters treated for 9 weeks with atrasentan showed no variation in MAP; however, selective ETB- and combined nonselective ETA- and ETB-receptor antagonists increased systemic blood pressure. After selective ETB-receptor blockade, plasma endothelin levels were augmented. Importantly, this increase was highly enhanced (more than 8-fold) by concomitant ETA-receptor antagonism. Furthermore, the left ventricle : body weight ratio of cardiomyopathic hamsters treated with A-192621, alone or in combination with atrasentan, was significantly increased. On the other hand, decreased left ventricular end-diastolic pressure was observed in cardiomyopathic hamsters after selective ETA- or combined nonselective ETA/ETB-receptor antagonism, while only selective ETA-receptor blockade reduced left ventricular endothelin levels. Our results suggest that, in congestive heart failure, ETBreceptors are essential to limit circulating endothelin levels, which may argue for improved cardiac benefits after long-term treatment with highly selective ETA-receptor antagonists.
WEB SERVICES INTERACTIONS: ANALYSIS, MODELING, AND MANAGEMENT
Authors: MAAMAR ZAKARIA , SHENG QUAN Z. , BENSLIMANE DJAMAL , YAHYAOUI HAMDI
Published: May 2008

This paper discusses how interactions between Web services engaged in composition scenarios are analyzed, modeled, and finally managed. Interactions are primarily considered as a means for conveying messages of different natures between separate components, for instance, Web services. To achieve better coordination and hence, avoid conflicts between Web services, in this paper interactions are handled by two layers known as business logic and support. The business-logic layer is the host of two flows known as control and transactional, whereas the support layer is the host of two additional flows namely exception and message. On top of the proposed layers and flows, context and policies are used to oversee the progress of interactions between Web services and to constrain the behavior of these Web services, respectively.
AN APPROACH TO CHECKING BEHAVIORAL COMPATIBILITY BETWEEN WEB SERVICES
Authors: CHAE HEUNG SEOK , LEE JOON-SANG , BAE JUNGHO
Published: May 2008

This paper proposes an approach to checking behavioral compatibility between Web services. If Web service B can be used in replacement of Web service A in such a way that the replacement is transparent to clients, Web service B is compatible to Web service A. We use state machines with guarded transitions to specify behaviors of Web services. To check compatibility between two Web services, we propose an extended version of the conventional methods rule, which has been used in object-oriented paradigm. To support our approach, we have implemented a tool. First, the tool constructs a state machine for a Web service whose behavior is expressed in WSDL and WSCI. Then, the tool can verify compatibility between Web services by using the extended methods rule.
TOTALLY ω-COMPUTABLY ENUMERABLE DEGREES AND BOUNDING CRITICAL TRIPLES
Authors: DOWNEY ROD , GREENBERG NOAM , WEBER REBECCA
Published: May 2008

We characterize the class of c.e. degrees that bound a critical triple (equivalently, a weak critical triple) as those degrees that compute a function that has no ω-c.e. approximation.
MASS PROBLEMS AND HYPERARITHMETICITY
Authors: COLE JOSHUA A. , SIMPSON STEPHEN G.
Published: May 2008

A mass problem is a set of Turing oracles. If P and Q are mass problems, we say that P is weakly reducible to Q if for all Y ∈ Q there exists X ∈ P such that X is Turing reducible to Y. A weak degree is an equivalence class of mass problems under mutual weak reducibility. Let [Formula: see text] be the lattice of weak degrees of mass problems associated with nonempty [Formula: see text] subsets of the Cantor space. The lattice [Formula: see text] has been studied in previous publications. The purpose of this paper is to show that [Formula: see text] partakes of hyperarithmeticity. We exhibit a family of specific, natural degrees in [Formula: see text] which are indexed by the ordinal numbers less than [Formula: see text] and which correspond to the hyperarithmetical hierarchy. Namely, for each [Formula: see text], let hα be the weak degree of 0(α), the αth Turing jump of 0. If p is the weak degree of any mass problem P, let p* be the weak degree of the mass problem P* = {Y | ∃X (X ∈ P and BLR (X) ⊆ BLR (Y))} where BLR (X) is the set of functions which are boundedly limit recursive in X. Let 1 be the top degree in [Formula: see text]. We prove that all of the weak degrees [Formula: see text], [Formula: see text], are distinct and belong to [Formula: see text]. In addition, we prove that certain index sets associated with [Formula: see text] are [Formula: see text] complete.
Rudolph Glossop and the development of ‘Geotechnology’
Authors: Williams R. , Norbury D.
Published: May 2008

The paper presents an account of the role played by Rudolph Glossop in the early development of geotechnical engineering and engineering geology within the UK. The hitherto unexplored Glossop Archive at Sheffield University has revealed documents covering the evolution of both disciplines including a business plan of 1939 that defined the objectives of Soil Mechanics Limited, the UK's first geotechnical company. The archive also contains substantial journals providing a fascinating account of business visits to overseas locations in Glossop's role as a main board director of the contractor John Mowlem & Co. Ltd. An unpublished personal journal has allowed a more complete understanding of Glossop's wartime role in London Docks in the construction of units for the Mulberry Harbour, a key factor in the success of the D-day landings in northern France in June 1944. The longstanding friendship with Alec Skempton and his admiration of the work of Karl Terzaghi were important factors in the development of Glossop's approach to the new discipline that he termed ‘Geotechnology’. This vision of the integrated business model for geotechnical contractors was to last until the 1980s and his commitment to the unified approach of soil mechanics, engineering geology and foundation engineering continues to remain the bedrock of many of the major UK consultancy practices. His belief in the importance of sharing knowledge is exemplified by his role in establishing the journals
Géotechnique
and the
Quarterly Journal of Engineering Geology
(QJEG) and his wide range of publications including important contributions on the history of the profession. On the thirtieth anniversary of the QJEG the engineering group of the Geological Society marked the contribution of Rudolph Glossop by establishing the prestigious Glossop Lecture and Award.
Engineering geology at Imperial College London; 1907–2007
Authors: de Freitas M.H. , Rosenbaum M.S.
Published: May 2008

The development of engineering geology as a distinct academic discipline in the UK is intimately linked to a course of lectures given by Herbert Lapworth to the Institution of Civil Engineers in London, in 1907. This course soon found its academic home in the Department of Geology at the then newly formed Imperial College of Science and Technology in South Kensington. This is an account of those who were involved with the subject during its first 100 years at Imperial.
Progesterone stimulates the proliferation of female and male cholangiocytes via autocrine/paracrine mechanisms
Authors: Glaser Shannon , DeMorrow Sharon , Francis Heather , Ueno Yoshiyuki , Gaudio Eugenio , Vaculin Shelley , Venter Julie , Franchitto Antonio , Onori Paolo , Vaculin Bradley , Marzioni Marco , Wise Candace , Pilanthananond Metaneeya , Savage Jennifer , Pierce Lisa , Mancinelli Romina , Alpini Gianfranco
Published: May 2008

During cholestatic liver diseases, cholangiocytes express neuroendocrine phenotypes and respond to a number of hormones and neuropeptides by paracrine and autocrine mechanisms. We examined whether the neuroendocrine hormone progesterone is produced by and targeted to cholangiocytes, thereby regulating biliary proliferation during cholestasis. Nuclear (PR-A and PR-B) and membrane (PRGMC1, PRGMC2, and mPRα) progesterone receptor expression was evaluated in liver sections and cholangiocytes from normal and bile duct ligation (BDL) rats, and NRC cells (normal rat cholangiocyte line). In vivo, normal rats were chronically treated with progesterone for 1 wk, or immediately after BDL, rats were treated with a neutralizing progesterone antibody for 1 wk. Cholangiocyte growth was measured by evaluating the number of bile ducts in liver sections. The expression of the progesterone synthesis pathway was evaluated in liver sections, cholangiocytes and NRC. Progesterone secretion was evaluated in supernatants from normal and BDL cholangiocytes and NRC. In vitro, NRC were stimulated with progesterone and cholangiocyte supernatants in the presence or absence of antiprogesterone antibody. Aminoglutethimide was used to block progesterone synthesis. Cholangiocytes and NRC express the PR-B nuclear receptor and PRGMC1, PRGMC2, and mPRα. In vivo, progesterone increased the number of bile ducts of normal rats, whereas antiprogesterone antibody inhibited cholangiocyte growth stimulated by BDL. Normal and BDL cholangiocytes expressed the biosynthetic pathway for and secrete progesterone. In vitro, 1) progesterone increased NRC proliferation; 2) cholangiocyte supernatants increased NRC proliferation, which was partially inhibited by preincubation with antiprogesterone; and 3) inhibition of progesterone steroidogenesis prevented NRC proliferation. In conclusion, progesterone may be an important autocrine/paracrine regulator of cholangiocyte proliferation.
The Ability of Selected Oral Microorganisms to Emit Red Fluorescence
Authors: Lennon A.M. , Buchalla W. , Brune L. , Zimmermann O. , Gross U. , Attin T.
Published: May 2008

Some novel caries detection and excavation devices rely on the ability of bacteria to produce red fluorescing compounds. The aim of this study was to examine the ability of selected oral microorganisms to emit red fluorescence. Streptococcus mutans, S. oralis, S. salivarius, S. sobrinus, Lactobacillus fermentans, L. casei, L. rhamnosus, Actinomyces naeslundi, A. israelii, Prevotella intermedia, and Fusobacterium nucleatum were inoculated onto Columbia agar with haemin and vitamin K and incubated anaerobically for up to 7 days in the dark. The resulting bacterial colonies were excited using filtered xenon light (405 ± 20 nm) and digitally photographed through a 530-nm high-pass filter. The red and green portions of the colony fluorescence were analyzed using a computer program and the red/green ratio was calculated. All colonies emitted both red and green fluorescence. The green outweighed the red portion for the following species (in descending order) S. oralis, S. salivarius, S. mutans, F. nucleatum and S. sobrinus. The red portion was higher for the following species (in descending order) P. intermedia, A. naeslundi, A. israelii, L. fermentans, L. rhamnosus and L. casei. With all the bacteria examined, one color portion generally outweighed the other, giving the visual impression of either red or green fluorescence. We conclude that red fluorescence is well suited to detection of the bacteria which cause dentin caries but it is not suitable as an indicator of the presence and activity of the streptococci involved in initial caries.
Influence of Cranberry Juice on Glucan-Mediated Processes Involved in Streptococcus mutans Biofilm Development
Authors: Koo H. , Nino de Guzman P. , Schobel B.D. , Vacca Smith A.V. , Bowen W.H.
Published: May 2008

Cranberry juice (CJ) has biological properties that may provide health benefits. In this study, we investigated the influence of CJ (pH 5.5) on several activities in vitro associated with the development of Streptococcus mutans UA159 biofilms. The ability of CJ to influence the adherence of S. mutans to either saliva- (sHA) or glucan-coated hydroxyapatite (gsHA), and to inhibit the glucan production by purified glucosyltransferases adsorbed to sHA was determined. For the adherence assays, we used both uncoated and saliva-coated bacterial cells. Furthermore, we examined whether CJ interferes with the viability, development, polysaccharide composition and acidogenicity of S. mutans biofilms. A solution containing equivalent amounts of glucose, fructose and organic acids at pH 5.5 was used as negative control. The adherence of S. mutans (uncoated and saliva-coated) to either sHA or gsHA treated with 25% CJ (v/v) was remarkably reduced (40–85% inhibition compared to control: p < 0.05), indicating that CJ effectively blocked the bacterial adherence to binding sites in salivary pellicle and in glucans. In contrast, when the bacterial cells alone were treated with CJ they adhered to the similar untreated surfaces. Cranberry juice (25%, v/v) also inhibited the activities of surface-adsorbed GTF B and C (70–80% inhibition compared to control, p < 0.05). The effect of CJ on the viability of microorganisms in biofilms was not significant. Biofilm formation and accumulation were significantly reduced by topical applications of 25% CJ (v/v) twice daily with 1-min exposures (p < 0.05). The biomass and insoluble glucan content of the biofilms in addition to its acidogenicity were significantly reduced by cranberry treatments (p < 0.05). Our data show that cranberry juice inhibited glucan-mediated biofilm development and acid production, and holds promise as a natural product to prevent biofilm-related oral diseases.
The Prevalence and Severity of Fluorosis in Children Who Received Toothpaste Containing either 440 or 1,450 ppm F from the Age of 12 Months in Deprived and Less Deprived Communities
Authors: Tavener J.A. , Davies G.M. , Davies R.M. , Ellwood R.P.
Published: May 2008

This study compared fluorosis in the upper central incisors of children from socially diverse backgrounds who had received either 440- or 1,450-ppm F toothpaste from 12 months of age. The children were resident in non-fluoridated districts in the north-west of England. They received either 440- or 1,450-ppm F toothpaste and advice regarding its use until the age of 5–6 years. Dental fluorosis (TF index) was assessed on digital images of dried teeth when the children (n = 1,268) were 8–10 years old. In the less deprived districts the prevalences of fluorosis (TF ≧0) for the 1,450- and 440-ppm F groups were 34.5 and 23.7% (p = 0.006). In the deprived districts the prevalences of fluorosis were 25.2 and 19.5% (p = 0.2). Overall the prevalences of TF ≧2 were 7 and 2.1% for the 1,450- and 440-ppm F groups and 2.2 and 0.2% for TF ≧3. These differences were statistically significant (p < 0.003). There was a strong association between the deprivation status of wards and fluorosis. Only 1 subject with a TF score of 3 was identified in the two most deprived quintiles of the Townsend score. It is concluded that careful targeting of programmes of this type to children living in high caries risk deprived communities carries only a small risk of aesthetically objectionable fluorosis (TF >2) whether low or high fluoride toothpastes are used. High fluoride (1,450 ppm F) toothpastes should not be provided on a community basis to very young children in less deprived communities.
Role of Chronic Inhibition of Dopamine-Metabolizing Enzymes in the Regulation of Renal Sodium and Phosphate Excretion in the Rat Remnant Kidney
Authors: Sampaio-Maia Benedita , Moreira-Rodrigues Mónica , Pestana Manuel
Published: May 2008

Background/Aims: The present study examined the effects of chronic selective or combined inhibition of type A monoamine oxidase (MAO) and catechol-O-methyltransferase (COMT) on daily urinary excretion of dopamine and metabolites and on natriuresis and phosphaturia in 3/4 nephrectomized (3/4nx) and Sham rats. Methods: The 3/4nx and Sham rats were placed in metabolic cages and received the MAO-A-selective inhibitor Ro-411049 (7.5 mg·kg–1 bid) and/or the COMT-selective inhibitor BIA 3-202 (30 mg·kg–1 bid) orally for 3 days during high sodium diet. Results: Selective COMT inhibition increased the urinary excretion of the deaminated metabolite (3,4-dihydroxyphenylacetic acid, DOPAC) and decreased the urinary excretion of the methylated (3-methoxytyramine, 3-MT) and deaminated plus methylated metabolite (homovanillic acid, HVA) in both groups. Selective MAO-A inhibition increased the urinary excretion of 3-MT and reduced the urinary excretion of both DOPAC and HVA in either 3/4nx or Sham rats. Combined inhibition of MAO-A and COMT did not significantly change the urinary excretion of DOPAC and markedly decreased the urinary excretion of 3-MT and HVA in both groups. Selective or combined inhibition of MAO-A and COMT did not alter the daily urinary excretion of dopamine, sodium or phosphate in either 3/4nx or Sham rats. Conclusions: Chronic selective or combined inhibition of MAO-A and COMT is not of major importance in regulating the dopamine-dependent natriuresis and phosphaturia in either 3/4nx or Sham rats.
Domain Structure and Pore Loops in the 2-Hydroxycarboxylate Transporter Family
Authors: Lolkema Juke S.
Published: May 2008

The 2-hydroxycarboxylate transporter (2HCT) family is a family of bacterial secondary transporters for substrates like citrate, malate and lactate. The family is in class ST[3] of the MemGen classification system that groups membrane proteins in structural classes based on hydropathy profile analysis. The combination of computational analysis of the proteins in class ST[3] and available experimental data on members of the 2HCT family has yielded a detailed structural model of the transporters. The core of the model is formed by two homologous domains with opposite orientation in the membrane. Each domain consists of 5 trans membrane segments and contains a pore loop between the 4th and 5th segment. The two pore loops enter the membrane-embedded part from opposite sides of the membrane (trans pore loops) and are believed to form the translocation pathway in the 3D structure. A genome wide study of the cellular location of the C-terminus of all Escherichia coli membrane proteins [Daley et al., 2005. Science 308:1321–1323] showed that the C-termini of the 19 E. coli proteins in class ST[3] were correctly predicted by the structural model.
Mesenchymal Stem Cells in Tissue Engineering
Authors: Leo Andrew J. , Grande Daniel A.
Published: May 2008

The repair of diseased or damaged cartilage remains one of the most challenging problems of musculoskeletal medicine. Tissue engineering advances in cartilage repair have utilized autologous and allogenic chondrocyte and cartilage grafts, biomaterial scaffolds, growth factors, stem cells, and genetic engineering. The mesenchymal stem cell has specifically attracted much attention because of its accessibility, potential for differentiation, and manipulability to modern molecular, tissue and genetic engineering techniques. Mesenchymal stem cells provide invaluable tools for the study of tissue repair when combined with a carrier vehicle/matrix scaffold, and/or bioactive growth factors. However, an underappreciated source of knowledge lies in the relationship between fetal development and adult tissue repair. The multitude of events that take place during fetal development which lead from stem cell to functional tissue are poorly understood. A more thorough understanding of the events of development as they pertain to cartilage organogenesis may help elucidate some of the unknowns of adult tissue repair.
Polymorphisms in Genes of the Renin-Angiotensin System and Cerebral Small Vessel Disease
Authors: Gormley K. , Bevan S. , Markus H.S.
Published: May 2008

Background: Genetic variation in the renin-angiotensin system (RAS) has been implicated in stroke, particularly the small vessel disease (SVD) subtype. Furthermore, there may be two distinct subtypes of cerebral SVD, isolated lacunar infarction (ILI) and ischaemic leukoaraiosis (ILA). Methods: 300 patients with well-phenotyped SVD and 600 controls were genotyped for five polymorphisms in the angiotensinogen (AGT) gene and eight polymorphisms within the angiotensin-converting enzyme (ACE) gene. Results: AGT and ACE polymorphisms and haplotypes were no more common in SVD cases as a whole or the two subtypes.Amongst hypertensives only, an AGT promoter polymorphism (–20A→C), was associated with the ILA subtype (multivariate odds ratio 1.716, 95% confidence interval 1.073–2.746, p = 0.024). Conclusions: RAS genetic variants are not strong risk factors for cerebral SVD. The AGT –20C allele may be a risk factor for the leukoaraiosis subtype amongst hypertensives.
Effect of the Hemodialysis Session on bcl-2 Expression in Peripheral Blood Mononuclear Cells in vivo
Authors: Koliousi E. , Vartholomatos G. , Katopodis K.P. , Kolaitis N. , Siamopoulos K.C.
Published: May 2008

bcl-2 is a proto-oncogene with a regulatory role in many conditions due to its marked inhibitory action on apoptosis. Reports regarding the effect of hemodialysis (HD) on apoptosis of mononuclear cells and in association with bcl-2 expression in particular, are controversial. The aim of the present study was to examine in vivo the influence of an HD session on bcl-2 expression of lymphocytes and monocytes. We measured quantitative bcl-2 expression with flow cytometry, in terms of antibodies bound per cell, in blood samples taken from 44 HD patients before and after an HD session. 27 patients (group I) were dialyzed with synthetic-type membranes and 17 (group II) with cellulose-type membranes. bcl-2 expression increased statistically significantly in lymphocytes (1,616 ± 718 to 1,894 ± 715 molecules/cell, p < 0.01) at the end of HD. Monocyte expression of bcl-2 was lower than in lymphocytes and almost did not change after the HD session (654 ± 446 to 698 ± 375 molecules/cell, p = NS). Comparison between the two groups did not reveal a significant difference in either the baseline bcl-2 expression or in the value of the increase after HD. We conclude that HD seems to decrease lymphocyte apoptosis independent of the biocompatibility of the dialyzer membrane.
Femoral Plaques Confound the Association of Circulating Oxidized Low-Density Lipoprotein With Carotid Atherosclerosis in a General Population Aged 35 to 55 Years
Authors: Langlois Michel R. , Rietzschel Ernst R. , De Buyzere Marc L. , De Bacquer Dirk , Bekaert Sofie , Blaton Victor , De Backer Guy G. , Gillebert Thierry C.
Published: May 2008

Objective—

Reported associations of oxidized low-density lipoprotein (oxLDL) with noninvasive measures of atherosclerosis are inconsistent. In the Asklepios Study cohort of asymptomatic subjects aged 35 to 55 years, we evaluated the relationship of circulating oxLDL with subclinical atherosclerosis in the carotid and femoral arteries.

Methods and Results—

Participants (n=2524, 51.5% females) completed a study questionnaire and underwent a clinical examination, blood analysis of oxLDL (mAb-4E6) and other risk markers, and ultrasound examination of intima-media thickness (IMT) and plaques in the left and right carotid and femoral arteries. oxLDL concentrations were highest in subjects with femoral plaques (n=658). In the group of subjects with carotid plaques (n=476), elevated oxLDL concentrations are related to concomitant femoral plaques detected in 54% of these subjects. Multivariate regression analyses (including anthropometric, hemodynamic, biochemical, and lifestyle variables) showed that femoral plaques are independently related to oxLDL whereas femoral IMT, carotid IMT, or carotid plaques were not independently associated with oxLDL.

Conclusion—

Circulating oxLDL is independently associated with femoral plaque and not with carotid artery wall damage.