bluuebunny/crossref_metadata_2025 huggingface dataset:
Metals in the sediments of Jauá Lake (Camaçari, Bahia, Brazil) following an episode of industrial contamination
Authors: da Silva E.M. , Navarro M.F.T. , Barros A.F. , Mota M.F.V. , Chastinet C.B.A.
Published: November 2008

The contamination of sediments caused by the deposition of industrial residues from titanium dioxide production, in sand dunes near a wetland was assessed through atomic absorption spectrometry. The contamination occurred near a shallow freshwater wetland called Jauá Lake, along the coast of Camaçari, Bahia, Brazil. Five core samples were collected, including a reference site, from Jauá Lake and one from a small lake, near the deposition site. Cores were cut in 20-cm sections. Fractions <63 μm were analysed for copper, cadmium, zinc, iron, lead, aluminium, mercury and titanium. Metal concentrations on the upper layer of sediments were, as a whole, higher than in lower ones. Concentrations from the reference site were similar to those from the other sites in Jauá Lake. Absolute values of most metals in the sediments of the Dunas Lake located near the contamination site were higher than in all other stations. The hypothesis, that:: (1) contamination coming from groundwater would contaminate the sediment; and (2) there would be a gradient of decreasing contamination from sites near the residue deposit to sites located further away, were rejected. The continuous removal of groundwater may have contributed to the reduction of further contamination. It is recommended that future studies examine the concentration of metals in plants and the role of plants in metal bioavailability.
Distribution of particulate trace metal in the southern part of the Patos Lagoon estuary
Authors: Niencheski L.F. , Baumgarten M.G.Z.
Published: November 2008

The analysis of suspended particles probably provides the best basis for assessing metal contamination of aquatic environments. However, such assessments cannot be made unless sufficient knowledge of natural contributions to observed concentrations is available. As different coastal areas are influenced by different natural inputs from their watersheds, assessments of natural versus anthropogenic contributions to metal concentrations must be made on a regional or site-specific basis.

The purpose of this research was to assess whether anthropogenic inputs of heavy metals into the surrounding waters of Rio Grande City were large enough to significantly affect concentrations in the southern part of the Patos Lagoon Estuary. Particulate samples were collected during 15 monthly cruises at seven fixed stations from May 1990 to June 1991 and analyzed under different seasonal and hydrological conditions.

Results show that the local inputs from urban, industrial and harbor activities in the city of Rio Grande have produced enrichments of copper, lead and zinc (but not iron) in suspended sediments in the three areas studied. The different behavior presented by these three areas are mainly due to hydrodynamic conditions and to distance from the harbor activities. Meteorological conditions which favor resuspension of bottom sediment, resulting in high total suspended matter concentrations, mask anthropogenic inputs.
Some implications of inter-basin water transfers for river ecosystem functioning and water resources management in southern Africa
Authors: Snaddon C.D. , Wishart M.J. , Davies B.R.
Published: November 2008

Inter-basin water transfers (IBTs) are a major form of river basin manipulation. In southern Africa they are increasingly being used to reconcile the problems of water distribution within the region. Despite their high cost and ‘high profile’ in terms of the complex engineering and technical inputs that they require, the ecological and social implications of such schemes have been, and continue to be, inadequately addressed.

Many rivers in southern Africa are shared resources, flowing through or between more than one province or country. The combined effect of climatic stochasticity, rapid population growth and inefficient water infrastructure is increasing the pressure on the river ecosystems of the region. As stresses on rivers continue to increase, re-distribution networks are rapidly assuming the status of a ‘growth industry’, but they have a disturbing and unaddressed potential for intra- and international conflict and for severe ecosystem perturbation.

This paper examines inter-basin water transfer schemes at three levels in terms of spatial and temporal scales in southern Africa. Each scheme augments water supply to the industrial centre of South Africa, the Province of Gauteng. We have selected a temporary intra-basin scheme built for emergency supply within the Vaal River (the major tributary of the Orange River), an inter-provincial scheme involving transfer of water from the Tugela River in KwaZulu/Natal to the Vaal River, and an international transfer scheme centred in Lesotho (the Lesotho Highlands Water Project), which shortly will move water from the headwaters of the Orange River, again to the Vaal River. These schemes illustrate some of the extremely complex ecological, geomorphological, chemical, social and political ramifications that occur when river basins are manipulated for water supply. Although pleas for detailed ecological studies of the effects of IBTs have been made over the past decade, they have fallen on deaf ears in administrative, engineering and political circles. We again caution that IBTs can be highly problematic, and expand the plea for intelligent and integrated planning and management, and for strict adherence to Environmental Impact Assessment (EIA) and Integrated Environmental Management (IEM) procedures for both future and extant schemes in the region.
Nutrient-phytoplankton production relationships in a groundwater-influenced tropical coastal lagoon
Authors: Herrera-Silveira Jorge A.
Published: November 2008

Interactions between nutrient and biotic components of phytoplankton in Celestún lagoon, a groundwater-influenced tropical coastal lagoon were studied. Gradients of nutrients, chlorophyll a, phaeopigments, production and respiration rates were estimated from March 1990 to March 1991. The inner zone of the lagoon was strongly affected by groundwater discharges with high concentrations of nitrate (35 μmol) and soluble reactive silica (400 μmol). The seaward zone was characterized by high salinity (<30‰) and low concentration of nutrients. The middle zone of the lagoon was characterized by intermediate values of salinity and high concentrations of soluble reactive phosphorus (>9 μmol) and ammonia (15 μmol). Seasonal chlorophyll a variations showed a gradient of high concentrations in the middle region (20–28 mg m-3) to low concentrations at both ends of the lagoon during the rainy season (5–8 mg m-3). Net primary production ranged from 0.1 to 2.2 g C m-3day-1, and showed a similar seasonal pattern in all stations, with a peak in the early rainy season and smaller secondary peak during the ‘nortes’ season. Multivariate analysis was carried out in order to describe different stages of nutrient-phytoplankton coupling. These were related to groundwater discharges and climatic patterns. The relationships between nutrient and phytoplankton showed a coupling between mineralization-import of nutrient patterns and respiration-production of phytoplankton. The dissolved inorganic nitrogen to soluble reactive phosphorus ratio in Celestún lagoon varied seasonally from 70:1 during the dry and rainy seasons, to <5:1 during the ‘nortes’ season. This suggested a potential shift in nutrient limitation for phytoplankton growth.
Challenges to the implementation of the ecosystem approach in the Great Lakes basin
Authors: Jones M.L. , Taylor W.W.
Published: November 2008

The end of a century is a good time to look back and see how past events have shaped both our present situation and our perspective on the future. In this essay, we do this in the context of the emergence of an ecosystem approach to management of the North American Great Lakes. Our goal is to (i) review how the ecosystem approach emerged and became institutionalized in the Great Lakes region and then (ii) discuss why implementation of the approach continues to pose profound challenges for Great Lakes citizens and institutions. We suggest how some of the greatest hurdles might be overcome and share our optimism that Great Lakes institutions are moving, albeit slowly, in the right direction. We have prepared this essay in memory of a former colleague and pioneer of the ecosystem perspective for Great Lakes management, W.J. (Jack) Christie. As we develop our thesis, we will highlight some of the many contributions Jack made, both to the science behind ecosystem management and to helping make the Great Lakes great again.
Composition and dynamics of autotrophic picoplankton and spectral light distribution in saline lignite mining lakes of Germany
Authors: Zippel B. , Schimmele M.
Published: November 2008

In two saline turbid mining lakes, the seasonal dynamics of autotrophic picoplankton (APP) were investigated. APP biomass accounted for 10–96% (annual average 48%) of the total autotrophic biomass. Eucaryotic picoplankton was dominant during spring and autumn (0.4–9 107 cells l-1). Picocyanobacteria appeared from June to September, reaching abundances of up to 1.3 × 108 cells l-1. The total phosphorus content varied in the range 7–46 µg P l-1 and chlorophyll a (chla) in the range 0.5–5.2 µg chla l-1. The euphotic zone (1%-light level) extended only over the upper part of the epilimnion during the 1997 growing season. Red light (620–720 nm) was available within the water body. Blue or green light (430–580 nm) was mostly absent because of the high contents of suspended particles in lakes. This may be a reason for the occurrence of only phycocyanin-rich picocyanobacteria in the lakes investigated. This study shows that the APP constitutes a significant part of the phytoplankton in these slightly saline (6.5–8%) turbid mining lakes. Because of their small cell size, higher uptake rates of inorganic nutrients and possibility of efficient utilization of low light intensities, they might have had an advantage for the development in the lakes investigated.
DNAPlotter: circular and linear interactive genome visualization
Authors: Carver Tim , Thomson Nick , Bleasby Alan , Berriman Matthew , Parkhill Julian
Published: November 2008

Summary: DNAPlotter is an interactive Java application for generating circular and linear representations of genomes. Making use of the Artemis libraries to provide a user-friendly method of loading in sequence files (EMBL, GenBank, GFF) as well as data from relational databases, it filters features of interest to display on separate user-definable tracks. It can be used to produce publication quality images for papers or web pages.

Availability: DNAPlotter is freely available (under a GPL licence) for download (for MacOSX, UNIX and Windows) at the Wellcome Trust Sanger Institute web sites: http://www.sanger.ac.uk/Software/Artemis/circular/

Contact:  artemis@sanger.ac.uk
Perception of edges and visual texture in the camouflage of the common cuttlefish,
Sepia officinalis
Authors: Zylinski S , Osorio D , Shohet A.J
Published: November 2008

The cuttlefish,
Sepia officinalis
, provides a fascinating opportunity to investigate the mechanisms of camouflage as it rapidly changes its body patterns in response to the visual environment. We investigated how edge information determines camouflage responses through the use of spatially high-pass filtered ‘objects’ and of isolated edges. We then investigated how the body pattern responds to objects defined by texture (second-order information) compared with those defined by luminance. We found that (i) edge information alone is sufficient to elicit the body pattern known as Disruptive, which is the camouflage response given when a whole object is present, and furthermore, isolated edges cause the same response; and (ii) cuttlefish can distinguish and respond to objects of the same mean luminance as the background. These observations emphasize the importance of discrete objects (bounded by edges) in the cuttlefish's choice of camouflage, and more generally imply that figure–ground segregation by cuttlefish is similar to that in vertebrates, as might be predicted by their need to produce effective camouflage against vertebrate predators.
Increased levels of regulatory T cells (Tregs) in human immunodeficiency virus-infected patients after 5 years of highly active anti-retroviral therapy may be due to increased thymic production of naive Tregs
Authors: Kolte L , Gaardbo J C , Skogstrand K , Ryder L P , Ersbøll A K , Nielsen S D
Published: November 2008

This study determines levels of regulatory T cells (Tregs), naive Tregs, immune activation and cytokine patterns in 15 adult human immunodeficiency virus (HIV)-infected patients receiving prolonged highly active anti-retroviral therapy (HAART) who have known thymic output, and explores if naive Tregs may represent recent thymic emigrant Tregs. HIV-infected patients treated with HAART with a median of 1 and 5 years were compared with healthy controls. Percentages of Tregs (CD3+CD4+CD25+CD127low), naive Tregs (CD3+CD4+CD25+CD45RA+) and activation markers (CD38+human leucocyte antigen D-related) were determined by flow cytometry. Forkhead box P3 mRNA expression and T cell receptor excision circles (TREC) content in CD4+ cells were determined by polymerase chain reaction and cytokines analysed with Luminex technology. Levels of Tregs were significantly higher in HIV-infected patients compared with controls, both after 1 and 5 years of HAART (P < 0·001), despite fully suppressed HIV-RNA and normalization of both CD4 counts, immune activation and cytokine patterns. Furthermore, levels of naive Tregs were elevated significantly in HIV-infected patients (P < 0·001) and were associated with thymic output measured as the TREC frequency in CD4+ cells (P = 0·038). In summary, Treg levels in HIV-infected patients are elevated even after 5 years of HAART. Increased thymic production of naive Tregs may contribute to higher Treg levels in HIV-infection.
Modulation of nuclear factor‐κB activity can influence the susceptibility to systemic lupus erythematosus
Authors: Kalergis Alexis M. , Iruretagoyena Mirentxu I. , Barrientos Magaly J. , González Pablo A. , Herrada Andres A. , Leiva Eduardo D. , Gutiérrez Miguel A. , Riedel Claudia A. , Bueno Susan M. , Jacobelli Sergio H.
Published: November 2008

Autoimmune diseases, such as systemic lupus erythematosus (SLE), result from deficiencies in self‐antigen tolerance processes, which require regulated dendritic cell (DC) function. In this study we evaluated the phenotype of DCs during the onset of SLE in a mouse model, in which deletion of the inhibitory receptor FcγRIIb leads to the production of anti‐nuclear antibodies and glomerulonephritis. Splenic DCs from FcγRIIb‐deficient mice suffering from SLE showed increased expression of co‐stimulatory molecules. Furthermore, diseased mice showed an altered function of the nuclear factor‐κB (NF‐κB) transcription factor, which is involved in DC maturation. Compared with healthy animals, expression of the inhibitory molecule IκB‐α was significantly decreased in mice suffering from SLE. Consistently, pharmacological inhibition of NF‐κB activity in FcγRIIb‐deficient mice led to reduced susceptibility to SLE and prevented symptoms, such as anti‐nuclear antibodies and kidney damage. Our data suggest that the occurrence of SLE is significantly influenced by alterations of NF‐κB function, which can be considered as a new therapeutic target for this disease.
Research note: Lectotypification of Nemalionopsis tortuosa Yoneda et Yagi, Thoreales, Rhodophyta
Authors: Kumano Shigeru , Seto Ryozo , Yoshida Tadao
Published: November 2008

The specimen (KYO 00020215) is designated here as the lectotype of Nemalionopsis tortuosa Yoneda et Yagi.
ON HEURISTIC PROCEDURES IN LINGUISTICS
Authors: Pericliev Vladimir
Published: November 2008

Heuristic procedures provide a useful tool in problem solving situations. However, their description and the study of the role they play in the solution process to lingustic problems have generally been ignored in linguistics. The paper illustrates several commonly used heuristic procedures in the sciences and shows their utility in the solution of two (simple) linguistic problems. Some merits of heuristic procedures are briefly discussed.
CROSSLINGUISTIC STUDIES ON CHILD LANGUAGE
Authors: Imedadze Natela
Published: November 2008

The author shares D. Slobin's opinion that crosslinguistic study is necessary to discover and verify the conceptual basis of speech development and operating strategies for the construction of concrete language.
The Self in Procedural Fairness
Authors: Sedikides Constantine , Hart Claire M. , De Cremer David
Published: November 2008

Procedural fairness (whether the organizational decision‐making process is perceived as fair) has profound psychological effects on organizational members. A vital reason for these effects is that organizational procedures communicate information which is relevant to the self. Specifically, this information is relevant to different types of self (individual, collective, relational) and, more importantly, to different motives within each type of self. As such, procedures satisfy the motives of uncertainty reduction and self‐enhancement (individual self), the motives of reputation and status (collective self), and the motives of belongingness and respect (relational self). We provide illustrative evidence in support of our conceptual map, discuss complexities, and offer suggestions for future research.
A dynamic model of the Bay of Biscay pelagic fleet simulating fishing trip choice: the response to the closure of the European anchovy (Engraulis encrasicolus) fishery in 2005
Authors: Vermard Youen , Marchal Paul , Mahévas Stéphanie , Thébaud Olivier
Published: November 2008

The scope of this paper is to describe, evaluate, and forecast fishing trip choices of the Bay of Biscay pelagic fleet using random utility modeling (RUM). First, alternative fishing trip choices of this fleet were identified using multivariate statistical methods based on species landings weighted by value and defined as distinct fishing activity or fisheries (termed métiers). A RUM was specified, which included trip components as attributes during the period 2001–2004 (a lagged percentage of the value per unit of effort of the main species caught, total value per unit of effort, and inertia in terms of changes from one métier to another). For the main métiers, the proportion of correct effort allocation is 90% during the calibration period of 2001–2004. The results from the RUM are used to parameterize a simulation model of trip choice. The model is used to predict trip choices in 2005, throughout most of which fishing was constrained by the closure of the European anchovy (Engraulis encrasicolus) fishery. Simulation results are compared with observed trip choices following the fishing ban: 80% of observed trip choices are correctly predicted by the model. The capacity of the behavioral model to predict responses to the closure is then discussed.
Physical modeling in sand
Authors: Altaee Ameir , Fellenius Bengt H.
Published: November 2008

Small-scale testing under 1 g conditions as well as in the centrifuge presupposes that a model and prototype have comparative behavior. The chief condition for agreement between model and prototype is that the initial soil states of both must be at equal proximity to the steady state line. Then, when stresses are normalized to the initial mean stress, the model will in all aspects behave similarly to the prototype. Scaling rules are presented that indicate the relations between stress, strain, and displacement for the model and the prototype in terms of geometric scale and stress scale. An obvious limit of scales is imposed by that the soil in the model can be no looser than the maximum void ratio. Similarly, it must not be denser than a value that corresponds to a prototype soil at the minimum void ratio. Three main areas of application of the approach in engineering practice are identified: design of representative 1 g small-scale model tests; reanalysis of data from conventional small-scale tests; and improving the versatility of centrifuge facilities in recognition of the fact that the centrifuge test does not need to be performed at equal levels of stress, when designed according to the new approach. Key words : physical modeling, sand, scaling relations, steady state, centrifuge testing.
TUBE DOMAINS AND RESTRICTIONS OF MINIMAL REPRESENTATIONS
Authors: SEPPÄNEN HENRIK
Published: November 2008

In this paper, we study the restrictions of the minimal representation in the analytic continuation of the scalar holomorphic discrete series from Sp(n, ℝ) to GL+(n, ℝ), and from SU(n, n) to GL(n, ℂ) respectively. We work with the realizations of the representation spaces as L2-spaces on the boundary orbits of rank one of the corresponding cones, and give explicit integral operators that play the role of the intertwining operators for the decomposition. We prove inversion formulas for dense subspaces and use them to prove the Plancherel theorem for the respective decomposition. The Plancherel measure turns out to be absolutely continuous with respect to the Lebesgue measure in both cases.
PERFORMANCE RELIABILITY BASED OPTIMIZATION CRITERION FOR ELASTIC STRUCTURES SUBJECT TO RANDOM LOADS
Authors: MARANO GIUSEPPE CARLO , GRECO RITA
Published: November 2008

A stochastic optimization which makes use of a reliability constraint, expressing a performance requirement, is proposed for linear elastic systems subject to random dynamic loads. The criterion selected for the optimum design is the minimization of a deterministic measure, whereas the constraint condition requires that system failure probability must be smaller than a given allowable level, where failure is associated to the first exceeding of system response from a safe domain. The proposed method is then developed for the optimum design of a Tuned Mass Damper, utilized for reducing undesirable vibrations originated in structures by random loads.

Unlike conventional TMD designs based on minimizing the mean-square response, a reliability-based performance measure is then considered in the proposed design, which properly accounts for uncertainties in loads. A sensitivity analysis is carried out and results are shown in a useful manner for TMD design decision support.
BAYESIAN SAMPLING PLANS WITH PROGRESSIVE CENSORING AND WARRANTY POLICY
Authors: TSAI TZONG-RU
Published: November 2008

The paper investigates the design of Bayesian sampling plan for the exponential lifetime model under progressive type-II censoring, in which items are manufactured in batches and sold to consumers with a general rebate warranty policy. Assume that the mean lifetime of items is random and varies from lot to lot. A cost model consists of the cost per item on test, the cost per item of test time and the costs of rejecting and accepting an item is established, and an algorithm is provided to determine the optimal Bayesian sampling plan which minimizes the expected average cost per lot. The use of the proposed method is illustrated by numerical results and an example. A sensitivity study is conducted to evaluate the influences of the removal scheme and using incorrect estimates for the hyper-parameters on the proposed sampling plans. The proposed method can be extended to the Weibull lifetime model as its shape parameter is known.
Effect of unloading followed by reloading on expression of collagen and related growth factors in rat tendon and muscle
Authors: Heinemeier K. M. , Olesen J. L. , Haddad F. , Schjerling P. , Baldwin K. M. , Kjaer M.
Published: November 2008

Tendon tissue and the extracellular matrix of skeletal muscle respond to mechanical loading by increased collagen expression and synthesis. This response is likely a secondary effect of a mechanically induced expression of growth factors, including transforming growth factor-β1 (TGF-β1) and insulin-like growth factor-I (IGF-I). It is not known whether unloading of tendon tissue can reduce the expression of collagen and collagen-inducing growth factors. Furthermore, the coordinated response of tendon and muscle tissue to disuse, followed by reloading, is unclear. Female Sprague-Dawley rats were subjected to hindlimb suspension (HS) for 7 or 14 days, followed by 2, 4, 8, or 16 days of reload (RL) ( n = 8 in each group). Age-matched controls were included for day 0, day 14 HS, and day 16 RL ( n = 8). mRNA expression levels for collagen I (COL1A1), collagen III (COL3A1), TGF-β1, connective tissue growth factor (CTGF), myostatin, and IGF-I isoforms were measured by real-time RT-PCR in Achilles tendon and soleus muscle. The tendon mass was unchanged, while the muscle mass was reduced by 50% after HS ( P < 0.05) and returned to control levels during RL. Collagen I and III, TGF-β1, and CTGF mRNA levels were unaltered by HS, although collagen III tended to decrease in muscle at day 7 HS. IGF-I isoforms were significantly induced in tendon after 7 days of HS ( P < 0.001), and mechanogrowth factor increased in muscle at day 14 HS ( P < 0.05). Reload increased muscle collagen I and III mRNA (>10-fold) ( P < 0.001) and growth factor expression ( P < 0.05), while the tendon response was limited to a moderate induction of collagen expression (2-fold) ( P < 0.05). Unloading of tendon and muscle tissue did not reduce expression of collagen and collagen-inducing growth factors, indicating that the response to unloading is not opposite that of loading. Furthermore, the tendon response was clearly different and less pronounced than the muscle tissue response.
Electrical Responses of Peritubular Membrane to Cationic Substitutions in Necturus
Authors: Teulon J. , Planelles G. , Anagnostopoulos T.
Published: November 2008

Eight cations were reversibly and isosmotically substituted for sodium (45 mM) in peritubular circulation of the proximal tubule of the doubly perfused Necturus kidney. Li, choline and tetramethylammonium produced small shifts in peritubular potential difference with no change in conductance. Tris- and tetraethylammonium depolarized the membrane by about 10 mV without affecting its conductance. Rb and Cs produced a decrease of membrane permeability to potassium. Potassium for sodium substitution depolarized the membrane (3.1 mV) and increased its conductance. It is concluded that none among the cations tested may be considered as readily less permeant than sodium across the peritubular membrane.
Influence of Inhibitors of the Renin-Angiotensin System and the Renal Prostaglandins on Furosemide-induced Changes in Renal Blood Flow
Authors: Orley John T. , Hook Jerry B. , Bailie Michael D.
Published: November 2008

The effects of inhibitors of the renin-angiotensin system and prostaglandin synthesis were used to study furosemide-induced changes in renal hemodynamics. Extracellular fluid volume expansion augmented the increase in renal blood flow to furosemide when compared to hydropenic animals. Indomethacin, a prostaglandin synthetase inhibitor, blunted the effect of furosemide in volume-expanded animals. Neither SQ 20,881, an angiotensin I converting enzyme inhibitor, nor 1-Sar-8-A1a-angiotensin II, an angiotensin II antagonist, modified the response to the diuretic. The initial transient decrease in renal blood flow seen following furosemide was not modified by volume expansion, indomethacin, SQ 20,881 or 1-Sar-8-A1a-angiotensin II.
Effect of Methylguanidine on Fluid and Sodium Reabsorption in Different Segments of Rat Kidney
Authors: De Santo N.G. , Capasso G. , Paduano C. , Giordano C.
Published: November 2008

The effects of methylguanidine (MG) were studied in proximal and distal tubules of the cortical nephrons of the rat kidney by the aid of various micropuncture techniques. Methylguanidine (5 × 10-4M/kg intravenously, as a bolus) depressed fluid and sodium reabsorption without affecting GFR. In proximal convoluted tubules, intravenous MG did not significantly affect the rate of isotonic fluid reabsorption measured with the split oil droplet technique; whereas, when MG (1 mM/1) was applied both from the peritubular side and intratubularly, isotonic fluid reabsorption was slightly depressed (p < 0.05). In the distal tubule, intravenous MG depressed fluid and sodium reabsorption.
Differences in Acidic Glycosaminoglycans in Cortical and Medullary Tissue in Human Kidney
Authors: Murata Katsumi
Published: November 2008

The components of acidic glycosaminoglycans (AGAG) prepared separately from cortical and medullary tissues of human male kidneys were analyzed by enzymatic methods. Heparan sulfate was the main component, comprising approximately half of total AGAG, and was significantly higher in the cortex than in the medulla. In the cortex, the major AGAG was heparan sulfate (67% of total AGAG) followed by dermatan sulfate (17%). In the medulla, the main AGAG was also heparan sulfate (45%) followed by hyaluronic acid (15%) and chondroitin 4-sulfate (16%). A possible role of the different AGAG composition in the two regions is discussed.
The Binding of Human Lysosomal Elastase to Glomerular Basement Membrane
Authors: Davies Malcolm , Hughes Kelvin T. , Thomas Gareth J.
Published: November 2008

The interaction of purified elastase with glomerular basement membrane and its antigens was studied. There appears to be at least two types of interaction. The first is a weak interaction and the enzyme can be removed simply by extended washing with neutral buffer. The second, stronger interaction is desorbed with high salt concentration at alkaline pH. The different interactions probably represent the binding of isoenzymes. Further experiments demonstrate that all isoenzymes degrade the membrane. Serum proteins prevent binding and inhibit the action of elastase on glomerular basement membrane.
Origin of Outgrowth from Isolated Glomeruli in Culture
Authors: Nørgaard Rytter
Published: November 2008

The primary cellular outgrowth from isolated glomeruli was identified by examinations of the ultrastructural changes occurring in the three glomerular cell types during culture and by light and electron microscopic autoradiographic preparations of isolated glomeruli incubated with 3H-thymidine. It is demonstrated that the visceral epithelial cells constitute the majority of cells in the primary glomerular outgrowth and that another cell type probably originates from the mesangial cells. A method is described to obtain rather pure cultures of proliferating visceral epithelial cells suitable for further studies of their metabolic properties.
Effect of Alloxan-Induced Diabetes on the Glomerular Filtration Barrier of the Rat
Authors: Evan Andrew P. , Luft Friedrich C.
Published: November 2008

To elucidate morphologic changes in glomeruli of rats made diabetic with alloxan 40 mg/kg, we examined the filtration barrier with light microscopy, transmission (TEM), and scanning electron microscopy (SEM). The rats were killed at 10 or 20 weeks. The presence of diabetes was verified by blood and urine glucose measurements. In vivo perfusion was carried out through the left ventricle with gluteraldehyde in cacodylate buffer. SEM and TEM were performed by conventional techniques. SEM revealed striking changes in both the epithelial and endothelial surfaces which were focal and progressive with time. The epithelial surfaces showed podocyte fusion with areas of frank necrosis. Occasional areas of regeneration were seen. The endothelium showed a loss in number and decrease in size of fenestrae, proliferation of microvilli, and appearance of irregular cellular processes. TEM confirmed the presence of cellular changes. The basement membrane was irregularly thickened and the mesangium was more prominent than in control animals. We conclude that not only is the basement membrane affected by diabetes, but also important endothelial and epithelial cell changes occur as well. These changes are best appreciated by SEM and have not been previously described.
Morphological Heterogeneity of Isolated Renal Basement Membranes
Authors: Carlson Edward C. , Kenney Cristina
Published: November 2008

The mammalian renal cortex is composed primarily of epithelial structures. These include renal corpuscles, tubules, and vascular components bounded by basement membranes and supported by extracellular matrix. In an effort to elucidate the morphological characteristics of these materials, we carried out a comparative electron microscopic study of the acellular renal cortex in the rabbit, rat, rhesus monkey, and human. Acellular tissue blocks were prepared as described elsewhere in this symposium [Carlson and Kenney: ‘Preparation and histoarchitecture of ultrastructurally pure glomerular basement membrane’]. In addition, basement membranes were isolated from purified fractions of renal tubules and glomeruli. Light microscopic studies of rabbit and rat acellular renal cortex showed that the extracellular matrix was less dense and basement membrane more delicate than those seen in either monkey or human. By electron microscopy, the renal interstitium demonstrated several major basement membrane types. These included tubular, peritubular capillary, Bowman’s capsular and glomerular basement membranes, all of which contributed to the delimitation of an uncompartmented connective tissue space. The thickness of basement membranes varies but usually human monkey rat rabbit. Tubular basement membranes were thicker than glomerular basement membranes (TBM/GBM = 2.3–2.7) with the differential least in rat and highest in rabbit. Paradoxically, isolated tubular basement membrane showed less structural rigidity than glomerular basement membranes. Further non-uniformity of individual basement membranes was demonstrated by enzyme digestion (trypsin and pepsin) of mixtures of isolated tubular and glomerular basement membranes. These showed that glomerular basement membrane was much less susceptible to enzyme solubilization than adjacent tubular basement membrane. Furthermore, the endothelial-mesangial surface of glomerular basement membranes endothelial-mesangial surface of glomerular basement membranes and the connective tissue surface of tubular basement membranes were preferentially digested by the enzymes, indicating a possible ‘sidedness’. In addition, variable surface-associated substances were demonstrated by treatment with ruthenium red which preferentially stained both surfaces of glomerular basement membranes while adjacent Bowman’s capsule and tubular basement membrane remained unstained. We conclude that the diversity of substructure in various basement membranes strongly favors a ‘nonunitary concept’ of these matrices and generally supports the idea that they are compositionally heterogeneous.
The Rate of Synthesis and Breakdown of Glomerular Basement Membrane Material at the Transition ‘Normal to Diabetes’ and ‘Diabetes to Normal’
Authors: Østerby Ruth , Gundersen Hans Jørgen G. , Gøtzsche Ole , Seyer-Hansen Kjartan
Published: November 2008

A considerable enlargement of the renal glomeruli is present very early after the acute onset of juvenile diabetes mellitus. In the hypertrophied glomeruli the surface area of the capillary walls, the filtration surface, is increased, and thereby also the amount of basement membrane in the capillary wall. The rate of development of this type of diabetic basement membrane accumulation has been studied in streptozotocin diabetic rats with 4-and 47-day duration of diabetes. During the first 4 days a 40% increase in the total amount of peripheral basement membrane material occurs, whereas the following period up to 47 days shows no further change. The structural changes of the glomerular capillaries seen in conjunction with the basement membrane accumulation comprise an enlargement of the filtration surface and capillary luminal volume. In another experiment, 4-week diabetic animals were transplanted with pancreatic islets. The renal structures were studied quantitatively after 4 weeks of normalization. It was found that the increased amounts of basement membrane material were still present.
Effect of Aging on Single Nephron Renin Content in Rats
Authors: Hayashi Matsuhiko , Saruta Takao , Nakamura Ryuichi , Kitajima Waichi , Kato Eiichi
Published: November 2008

To investigate the relation between renin content in each juxtaglomerular apparatus and reduction of plasma renin activity (PRA) with aging, the PRA and microdissected superficial or juxtamedullary single nephron renin content (SNRC) were determined in 5 young (3–6 months) and 5 aged (13–18 months) rats fed on a normal salt diet. The mean value of the PRA in the aged group was significantly lower than that of the young group. A highly significant correlation was found between the RPA and mean values of the superficial SNRC. The mean values of both the superficial and deep SNRC in the aged rats were significantly lower than those of the corresponding zones in the young rats. It is suggested that decreased synthesis of renin in each juxtaglomerular apparatus is an important factor in the decreased PRA observed with aging.
Effect of Prostaglandin Inhibitors on Renal Function in the Hypothyroid Rat
Authors: Michael U.F. , Meeks L.A.
Published: November 2008

The mechanisms of the abnormal renal tubular handling of sodium and water in hypothyroidism are still unexplained. Since prostaglandins (PG) have been shown to diminish the tubular reabsorption of both sodium and water, this study was undertaken to examine the possibility that the tubular abnormalities observed in hypothyroidism are prostaglandin mediated. Renal clearance studies were performed in rats before and after administration of two prostaglandin synthetase inhibitors. There was no significant difference in the PG-inhibitor induced absolute and percentage decrease of sodium and fluid excretion between the normal and hypothyroid rats during mild volume expansion. This indicates that prostaglandins are not responsible for the increased fractional sodium and water excretion in hypothyroid animals.
Biochemistry of Glomerular Basement Membrane Components Purified by Nondisruptive Techniques
Authors: Cohen Margo P. , Wu Van-Yu
Published: November 2008

In contrast to the fragmentation and loss of spatial arrangement seen in preparations of basement membrane isolated after sonic disruption, the architectural integrity of glomerular basement membrane is preserved with the described technique of osmotic lysis and sequential detergent treatment. The biochemistry of components solubilized without pepsin digestion from GBM prepared with this technique is described.
Glomerular Permeability for Proteins of High Molecular Weight Entrapped in Liposomes
Authors: Lubec G. , Kühn K. , Latzka U. , Reale E.
Published: November 2008

The glomerular filtration barrier is known to be negatively charged. Previous experiments have shown the importance of the electrical charge for permeability. We looked for permeability characteristics of proteins entrapped in liposomes with negative and positive charge detecting that the positive charge enables the protein to pass the glomerular filtration barrier.
The Mechanism of Acetate Stimulation of PAH Transport in Rat Kidney Fragments
Authors: Kliger Alan S. , Hollyer Ruth , Preuss Harry G.
Published: November 2008

Accumulation of p-aminohippurate (PAH) by rat kidney fragments incubating in vitro is enhanced as medium pH rises from 7.4 toward 7.8. Since medium pH increases from 7.4 to 7.8 over a 90-min period in the presence of acetate, we were unsure whether acetate had any direct stimulatory effect on transport. Rat renal fragments incubating in acetate showed no enhanced PAH accumulation at 30 and 60 min when medium pH was less than 7.6 but did increase approximately 25% after 90 min when pH approached 7.8. By a number of different procedures, we consistently found that when medium pH was not allowed to rise, acetate did not stimulate PAH accumulation. We conclude that at an initial pH of 7.4, acetate stimulation of PAH uptake by rat kidney fragments during the course of a 90-min incubation can be explained almost entirely by a rise in pH to a more optimal range for transport. In contrast, stimulation of PAH accumulation by lactate and pyruvate cannot be explained solely by changes in medium pH.
Influence of Prostaglandins A1, E1, E2, and F2α on Renal Blood Flow and Plasma Renin Activity
Authors: Neumayer H.-H. , Wagner K. , Schuhze G. , Laubner P. , Maiga M.K. , Molzahn M.
Published: November 2008

The effects of different prostaglandins (PG) on serial determinations of renal blood flow (RBF), mean arterial blood pressure (MABP), renal vascular resistance (RVR) and renin release were investigated in the conscious, chronically instrumented dog. 2 months after right-sided nephrectomy, female beagle dogs (n=6) were implanted with an electromagnetic flow probe and an inflatable pneumatic cuff around the left renal artery, and a catheter was inserted into the aorta above the renal artery. In repeated experiments, different prostaglandins (PGA1, E1, E2 and F2α) were infused above the renal artery at increasing doses (infusion time 15 min, doses 0.03–1.0µg min-1 kg-1). Lower and medium doses induced an increase of RBF, which returned to or were slightly below control levels with higher doses. PGA, appeared to be the most potent vasodilator with a significant hypotensive activity and the greatest augmentation of RBF. Simultaneously, renin release was most pronounced by PGA,.
Effect of Albumin Microinfusion on Proximal Tubular Pressure
Authors: Carmines Pamela K. , Tanner George A.
Published: November 2008

The present study tested the idea that protein in tubular fluid is responsible for an increase in resistance of Henle’s loops in the nephrotic syndrome. Single proximal tubules of anesthetized, normal rats were microinfused with an isotonic equilibrium solution containing 0–250 mg/100 ml bovine serum albumin while proximal tubular pressure (PTP) was continuously recorded. Microinfusion at 16 and 40 nl/min produced significant (p < 0.01) increments in PTP. There was no significant effect (p > 0.50) of albumin. These results suggest that moderate concentrations of albumin in tubular fluid do not cause an increase in resistance to tubular fluid flow.
Compensatory Renal Hypertrophy in Sprague-Dawley Rats
Authors: Finn William F.
Published: November 2008

The factors responsible for the increase in glomerular filtration rate associated with compensatory hypertrophy in Sprague-Dawley rats were studied 2 weeks following uninephrectomy. In sham-operated rats, the single nephron glomerular filtration rate (SNGFR) was 40 nl/min and the calculated glomerular plasma flow (GPF) was 138 nl/min. Proximal intratubular free-flow (Pτ) and stop-flow (PSF) hydrostatic pressures were 12 and 34 mm/Fig. respectively. The estimated glomerular capillary hydrostatic pressure (PGC) was 49 mm Hg and the estimated efferent effective ultrafiltration pressure (PufEA) was 12 mm Hg, indicating filtration pressure disequilibrium. The specific ultrafiltration coefficient was calculated to be 0.039 nl/s · mm Hg per glomerulus. In uninephrectomized rats, SNGFR increased to 61 nl/min and the calculated GPF increased to 266 nl/min. Pτ was 12 mm Hg; PGCe was 49 mm Hg and PUFEA was 15 mm Hg. Kfwas calculated to be 0.053 nl/s · mm Hg per glomerulus. These data indicate that in Sprague-Dawley rats under conditions of filtration pressure disequilibrium, the increase in GFR associated with compensatory hypertrophy is in part related to a significant change in Kf
Effect of Beta-Receptor Antagonists on HgCl2-Induced Acute Renal Failure in Rats
Authors: Gaál Katalin , Siklós Judit
Published: November 2008

During the first 48 h of HgCl2-induced acute renal failure (ARF), a single intraperitoneal injection of 100–100 µg/kg of the beta-adrenergic blockers pindolol, pro-pranolol and practolol caused a significant rise in urinary sodium excretion and a decrease in plasma renin activity (PRA), renal cortical renin activity (RRA) and urinary catecholamine excretion. A single intraperitoneal injection of 3 mg/kg HgCl2 resulted in ARF characterized by progressive azotemia, a transient increase in PRA, a progressive rise in RRA and urinary catecholamine excretion. After pretreatment with these beta blockers, PRA, RRA and urinary catecholamine excretion remained unchanged and azotemia was markedly reduced; urine flow rates did not fall, and were significantly higher than control flows till after 48 h. These results indicate that pretreatment with beta blockers decreases the severity of ARF, though they cannot prevent is; that increased activity of the sympathetic nervous system is involved in ARF and that increase in RRA may be an aggravating factor in the pathomechanism of the nephrotoxic model in ARF.
Prostaglandins Do Not Mediate the Renal Effects of Bradykinin
Authors: Strand James C. , Gilmore Joseph P.
Published: November 2008

Renal responses to the infusion of bradykinin during the simultaneous administration of indomethacin were similar to those obtained before prostaglandin synthesis inhibition, except that sodium excretion was significantly augmented. These results indicate that renal prostaglandins do not mediate the vasodilator actions of bradykinin.
Antidiuresis and Decreased Sodium Excretion during Cyclo-Oxygenase Inhibition in the Conscious Dog
Authors: Walker Benjimen R.
Published: November 2008

Studies were undertaken to further elucidate the role of endogenous prostaglandins in normal renal function in the awake dog. Meclofenamate (2 mg/kg and 2 mg/kg/h, i.v.) was administered after control measurements. Parallel time control experiments were also performed. Inhibition of renal prostaglandin synthesis was documented by significant reduction in urinary prostaglandin E2 excretion rate. Urine flow and sodium excretion were reduced by meclofenamate infusion. In addition, fractional excretion of sodium was reduced, implying enhanced sodium reabsorption during prostaglandin synthesis inhibition. Renal hemodynamics, glomerular filtration and systemic hemodynamics were unaffected. It is concluded that endogenous prostaglandin release is important in influencing sodium and water excretion in the conscious dog.
In vivo Staining of the Kidney with Alcian Blue: An Adjunct to Morphological and Physiological Studies
Authors: Bankir Lise , Hollenberg Norman K.
Published: November 2008

Techniques for in vivo staining of the kidney with Alcian blue are described. It results in a vivid coloration of the glomeruli and of the different renal zones which has proved very useful both to demonstrate renal morphology and to facilitate some physiological studies including precise delimitation of kidney zones counting and isolation of glomeruli, localization of microspheres and studies of renal perfusion patterns.
Influence of Prostaglandin A1 on Renal Filtration, Hemodynamics and Excretion
Authors: Wagner K. , Neumayer H.H. , Schultze G. , Schwietzer G. , Schudrowitsch L. , Ruf W. , Molzahn M.
Published: November 2008

The effect on renal function of a 210-min infusion of PGA1 into the aorta of 10 conscious beagle dogs has been investigated. In the sodium-replete group, PGA1 caused an increase in the glomerular filtration rate (GFR) (24%), renal blood flow (17%) and sodium excretion (20%). By contrast, in the sodium-depleted group, PGA1 caused a considerable reduction of GFR (25%) and sodium excretion (51%). In this group, baseline renal blood flow was lower, and there was no further reduction during PGA1 infusion. Fractional sodium excretion was unchanged in the sodium-replete dogs, but was reduced in the sodium-deplete state. Plasma renin activity was markedly elevated and further increased in the sodium-deplete group, but it was nearly unchanged in the sodium-replete group. This difference in renal response to exogenous PGA1 might be due to interaction with the renin-angiotensin system, which was markedly stimulated by sodium depletion and additionally by prostaglandin infusion.