bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect on the planktonic community of the chemical program used to control water hyacinth (Eichhornia crassipes) in Guadalupe Dam, Mexico
Authors: Lugo A. , Bravo-Inclán L.A. , Alcocer J. , Gaytán M.L. , Oliva Ma.G. , Sánchez Ma.del R. , Chávez M. , Vilaclara G.
Published: November 2008

Guadalupe Dam is a reservoir located into the Metropolitan area of Mexico City, which had been infested with water hyacinth (Eichhornia crassipes) for more than 12 years. In 1993 a management program was conducted in the reservoir. The main activities included the use of aquatic herbicides and mechanical control. The goal of this study was to monitor the composition and fluctuation of the planktonic community during the chemical control program. Five sampling stations were selected. Six samplings were made during the period of herbicides applications (July to November 1993) and one sampling more, used as control, was performed four months after the last application (March 1994). Herbicides diquat and 2,4-D amine were used in the chemical control program. Variables measured included temperature, dissolved oxygen, pH, chlorophyll a and numbers of phytoplankton, ciliates, rotifers, cladocerans and copepods. The reservoir is eutrophic, with high concentrations of chlorophyll a and low values of Secchi disc depth. Thermally, the dam seems to be warm monomictic. The infestation of aquatic weeds at the beginning of the program reached 95% of surface area. Two main effects of the herbicide application were observed. The first was the direct toxic effect of the chemicals on the growth and density of phytoplanktonic species, which lead to a reduction in zooplankton density related to food shortage. The second effect was indirect caused by the decomposing hyacinths which depleted dissolved oxygen concentrations. The oxygen deficit greatly affected the biological community. Although the chemical control program of Guadalupe Dam water hyacinth had a notable effect on the planktonic community, it recovered promptly. After the weed control program, the Guadalupe dam remained eutrophic. Although water hyacinth was eliminated, it was replaced by a large phytoplankton bloom.
Spatial variations in trace metal and stable isotope content of autochthonous organisms and sediments in the river Po system (Italy)
Authors: Camusso M. , Balestrini R. , Martinotti W. , Arpini M.
Published: November 2008

Variations in (a) carbon and nitrogen stable isotope composition (as δ13C and δ15N), and (b) trace metal content of sediments and biota (algae, invertebrates and fish) were investigated at four sites along the river Po (from the middle reaches to the delta) and one site in the coastal Adriatic area influenced by the river. The aim was to begin accumulating a database to help interpret differences in the accumulation of toxic substances in biota and sediments, elucidating how food sources and feeding strategies change between areas of the system differing in terms of anthropogenic influence and distance from the river mouth. C content and δ13C and δ15N were determined on biological tissue and sediment samples using a continuous flow isotope ratio mass spectrometer. Trace metal concentrations were assayed by electrothermal (Cd, Cu, Cr, Ni, Pb) or flame (Zn) atomic absorption spectrometry after acid digestion. Hg was assayed on solid samples on an automated mercury analyser using the vapour generation technique. In the sediments, depletions of the 13C isotope at the post-Lambro site (downstream) relative to the upstream Lambro site were indicative of the significant pollutant input from this tributary to the Po. Mercury, cadmium and zinc concentrations in sediments were two-to-three times higher downstream compared to upstream. Differences in carbon and nitrogen isotope signatures in fish species among the two Lambro sites and the last stretch of the Po indicated variations in the type of food and primary carbon sources. Only for chromium were concentrations significantly higher in fish muscle from the post Lambro site than from upstream of the Lambro or the last reaches of the Po. Mean levels of cadmium and zinc in the muscle of omnivorous fish at the four river sites were low and similar (< 0.01 to 0.02 μg g-1 for Cd, 22–31 μg g-1 for zinc), while between-site differences were found for the other metals. Only for mercury did bioaccumulation reflect trophic level movement.
A case analysis of strategies in ecotourism development
Authors: Masberg B.A. , Morales N.
Published: November 2008

Ecotourism is a form of tourism which focuses on contributing to the preservation of natural and cultural resources while promoting economic contribution to local communities. Certain factors have been identified in the literature to optimize both preservation and economic contribution, but the strategies to accomplish these factors have not been defined. The purpose of this research was to identify through case analysis how each of the success factors in ecotourism development (i.e. an integrated approach, planning and a slow start, education and training, maximize local benefits, and evaluation and feedback) have been implemented in ecotourism cases. A series of ecotourism cases were analyzed. The success factors were identified and the strategies described under each factor were recorded. The data collected for all cases were pooled for each of the success factors and a matrix of five success factors with the corresponding strategies was created. Strategies that appeared as ‘recommended’ in the cases were not included in the analysis. The results indicated that factors and strategies differed. Within each factor there is no predominant strategy. Success factors should be re-evaluated and factors identified using an ecosystem management approach which puts the health of the environment as the foundation of tourism development. Standards need to be set and then strategies assigned to maintain standards for preservation and economic well-being.
Induction of systemic resistance in Arabidopsis thaliana in response to a culture filtrate from a plant growth‐promoting fungus, Phoma sp. GS8‐3
Authors: Sultana F. , Hossain Md. M. , Kubota M. , Hyakumachi M.
Published: November 2008

The plant growth‐promoting fungus (PGPF), Phoma sp. GS8‐3, isolated from a zoysia grass rhizosphere, is capable of protecting cucumber plants against virulent pathogens. This fungus was investigated in terms of the underlying mechanisms and ability to elicit systemic resistance in Arabidopsis thaliana. Root treatment of Arabidopsis plants with a culture filtrate (CF) from Phoma sp. GS8‐3 elicited systemic resistance against the bacterial speck pathogen Pseudomonas syringae pv. tomato DC3000 (Pst), with restricted disease development and inhibited pathogen proliferation. Pathway‐specific mutant plants, such as jar1 (jasmonic acid insensitive) and ein2 (ethylene insensitive), and transgenic NahG plants (impaired in salicylate signalling) were protected after application of the CF, demonstrating that these pathways are dispensable (at least individually) in CF‐mediated resistance. Similarly, NPR1 interference in npr1 mutants had no effect on CF‐induced resistance. Gene expression studies revealed that CF treatment stimulated the systemic expression of both the SA‐inducible PR‐1 and JA/ET‐inducible PDF1.2 genes. However, pathogenic challenge to CF‐treated plants was associated with potentiated expression of the PR‐1 gene and down‐regulated expression of the PDF1.2 gene. The observed down‐regulation of the PDF1.2 gene in CF‐treated plants indicates that there may be cross‐talk between SA‐ and JA/ET‐dependent signalling pathways during the pathogenic infection process. In conclusion, our data suggest that CF of Phoma sp. GS8‐3 induces resistance in Arabidopsis in a manner where SA and JA/ET may play a role in defence signalling.
Anucleated cryptophyte vestiges in the gonyaulacalean dinoflagellates Amylax buxus and Amylax triacantha (Dinophyceae)
Authors: Koike Kazuhiko , Takishita Kiyotaka
Published: November 2008

Cryptophyte vestiges showing selective digestion of nuclei were found in the gonyaulacalean dinoflagellates Amylax buxus (Balech) Dodge and Amylax triacantha (Jörgensen) Sournia. They emitted bright yellow‐orange fluorescence (590‐nm emission) under epifluorescent microscopy and possessed U‐shaped plastids, suggesting the vestiges were active in photosynthesis. Under transmission electron microscopy, the plastid was characterized by a loose arrangement of two to three thylakoid stacks and included a stalked pyrenoid, as in the cryptophyte genus Teleaulax. Indeed, molecular data based on the plastid small‐subunit rRNA gene demonstrated that the vestiges in Amylax originated from Teleaulax amphioxeia. The stolen plastid (kleptoplastids) in Dinophysis is also derived from this cryptophyte species. However, in sharp contrast to Dinophysis, the plastid of the vestige in Amylax was surrounded by a double layer of plastid endoplasmic reticulum, and within the periplastidal area, a nucleomorph was retained. The vestiges also possessed mitochondria with characteristic plate‐like cristae, but lost the cell‐surface structure. The phagocytotic membrane of the dinoflagellates seemed to surround the cryptophytes right after the incorporation, but the membrane itself would probably be digested eventually. Remarkably, only one cryptophyte cell among 14 vestiges in a cell of A. buxus had a nucleus. This is the first recording of possible kleptoplastidy in gonyaulacalean dinoflagellates, and documents the strategy of a dinoflagellate involving the selective elimination of the cryptophyte nucleus.
MITRA‐VARUNA, INDRA, LES NĀSATYA COMME PATRONS DES TROIS FONCTIONS COSMIQUES ET SOCIALES
Authors: DUMÉZIL GEORGES
Published: November 2008

En 1941 et en 1945, dans Jupiter Mars Quirinus I p. 61 et III (ch. I), j'ai proposé d'interpréter la séquence des dieux arya de Mitani — Mitra‐Varuna, Indra, les Nāsatya — à la lumière du système indo‐iranien des trois fonctions cosmiques et sociales, Mitra‐Varuna représentant et engageant la souveraineté sous ses deux aspects juridique et magique, Indra réprésentant et engageant la force guerrière et les guerriers, les jumeaux Nāsatya (ou Aśvin) représentant et engageant la fécondité et la vitalité, et du même coup le tiers‐état des producteurs. Je voudrais systematiser et compléter les arguments que j'ai avancés pour établir cette interprétation. Je dois procéder en deux temps: d'abord montrer que ce groupement mitanien de divinités n'est pas fortuit, isolé, mais se retrouve dans des faits védiques (rituels, mythiques, théologiques); ensuite montrer que, dans ces faits védiques, la signification du groupement est bien celle de la hiérarchie des trois fonctions.
Comptes rendus
Authors: Holmer Nils M. , Malmmberg Bertil
Published: November 2008

L. L. Hammerich, Laryngeal before Sonant (Det Kgl. Danske Videnskabernes Selskab, hist.‐filol. Meddelelser

Marian Molé, Contributions à l'étude du genre grammatical en hittite

Karl Bouda, Lakkische Studien (Bibliothek der allgemeinen Sprachwissenschaft, herausgegeb. von H. Krahe; dritte Reihe). Heidelberg

Diedrich Westermann, Sprachbeziehungen und Sprachverwandt‐schaft in Afrika (Sitzungsberichte der deutschen Akademie der Wissenschaften zu Berlin, Phil.‐Hist. Klasse, 1948, KO. 1). Berlin

Marguerite Durand, Voyelles longues et voyelles brèves. Essai sur la nature de la quantité vocalique. Collection linguistique, publiée par la Société de linguistique de Paris
A MODERN ENGLISH MODEL OF ‘SIMPLE’ GRAMMAR FOR NATURAL LANGUAGES
Authors: Pak Ty
Published: November 2008

O. Abstract

A natural language is presented as a triple, (W, Nom, Sbst), where W is the set of non‐lexical (primitive) sentences, each having the unquantified atomic form of the sentence in predicate logic with its arguments (constituents) denoted by dummy symbols and Sbst is the operation of substitution, which transforms primitive sentences into ordinary lexical sentences by replacing the dummy symbols with nominals, the output of Nom, nominalization, which is an operation applying to both primitive and lexical sentences as input. The sentence, primitive or lexical, has no molecular complexity, as so‐called compound and complex sentences using various conjunctions are shown to be simple sentences with the atomic form. The theory is illustrated by a complete ‘simple’ grammar of Modern English.
WHY TREES IN SYNTAX?
Authors: Karlgren Hans
Published: November 2008

For better and for worse, modern linguistics when at all mathematical is mostly preoccupied with tree structure (or trivially equivalent structures such as labelled bracketings). This choice of representation is justified mainly by long tradition, and in view of the formal difficulties in transformational grammar alternatives should be seriously investigated. Especially, the use of more general graphs than trees should be at least attempted. A preliminary exploration of how graphs could be used with less prejudice in syntax strengthens the suspicion that trees are not necessarily the most adequate tools for describing sentence structure.
L'ACQUISITION DU FRANÇAIS PAR LES ENFANTS QUEBECOIS FRANCOPHONES1
Authors: Méar‐Crine A. M.
Published: November 2008

Cet article met l'accent sur le fait que l'acquisition du langage ne se réduit pas à l'acquisition d'un systéme de règles linguistiques mais qu'elle implique également l'acquisition d'un système de règles sociolinguistiques. On examine les notions de compétence/performance, les différentes phases de l'acquisition du langage, l'apprentissage des règles linguistiques et sociolinguistiques. On insiste sur le fait qu'il est primordial de caractériser les différences qui existent entre les répertoires linguistiques des différents groupes d'enfants francophones au Québec, avant de mettre sur pied un programme pour l'enseignement du français.
LATIN VOWEL REDUCTION AND THE REALITY OF PHONOLOGICAL RULES
Authors: Janson Tore
Published: November 2008

In the Latin language, there were extensive reductions of noninitial short vowels in the period immediately preceding the literary period (starting with Plautus around 200 B. C.). One of these reductions is discussed here from several different points of view. First, a philological analysis of the available data shows that the traditional picture of the development is incorrect in important respects. Secondly, an attempt is made to assess the phonetical plausibility of a revised picture of the sound change. Thirdly, it is demonstrated that the data of early literary Latin should be seen as reflections of a process of lexical diffusion that was just about finished. Lastly, it is pointed out that the rules describing the situation in literary Latin can hardly in any sense be taken to reflect any part of the speaker's behavior, but may well be conceived to mirror a strategy of perception.
APPLES OF GOLD IN PICTURES OF SILVER: WHERE HAVE ALL THE WORDS GONE?
Authors: Rivers Wilga M.
Published: November 2008

“I love smooth words like gold‐enameled fish Which circle slowly with a silken swish” (Elinor Wylie).
THE DISTRIBUTION OF DOUBLE DETERMINERS IN SWEDISH: DEN SUPPORT IN D*
Authors: Santelmann Lynn
Published: November 2008

Abstract. This article examines the distribution of the double definiteness construction in Swedish, where definite noun phrases appear with both a pre‐nominal definite article and a post‐nominal suffixal definite article. It is argued that the prenominal article is inserted to support features in D° only when the head noun plus the suffixal article cannot raise into D° and support the features there. The head noun fails to raise to D° in three contexts: in emphatic expressions, where the suffixal article cannot support the emphasis at PF; with pre‐nominal adjectives, where N° remains in situ to license adjectival inflection and where there is an intervening head that prevents the head noun from raising to D°.
THE STRUCTURE OF THE ICELANDIC NP
Authors: Sigurodsson Halldór Ármann
Published: November 2008

Abstract. This paper develops a (QP and a) DP analysis of the Icelandic NP, dealing primarily with prenominal modifiers and postnominal genitives. The paper argues that prenominal quantifiers and determiners head their own projections (QP and DP), whereas attributive adjectives are head‐adjoined to nouns. In addition, it is suggested that the minimal NP in morphological case languages, such as Icelandic and German, is a complement of a functional head, K, that hosts an m‐case feature, and attracts nouns, either in LF, as in German, or in ‘overt syntax’, as in Icelandic. Thus, the general noun‐genitive order in Icelandic possessive constructions is derived by overt N‐movement to K.
LOCALIZING HISTORICAL CLUES USING IRT AND PETROGRAPHIC ANALYSES AT VILLA MIRABELLO, MONZA (ITALY)*
Authors: ROSINA E. , DELLA TORRE S. , GASPAROLI P. , LAZZARONI L. , DI BELLA L. , CASTIGLIONI A. , RADAELLI M. , SOTGIA C.
Published: November 2008

The rebuilding of Villa Mirabello started in 1666. Built on designs of Gerolamo Quadrio, the project refurbished and enlarged a smaller 16th century country house (‘casa da nobile e da massaro’). Archival documents report on the remodelling, which consisted of selective demolition of portions of the structure, re‐using most of the masonry as the core of the new building, and the reinforcement of retained masonry by insertion of ‘ceppo’ stone quoins to update new exteriors. The aim of Quadrio was to create an elegant and sumptuous mansion, suitable for noble owners such as Giuseppe Durini and his family. The plan and a small part of original finishing (‘marmorino’ plaster decoration) are recognizable nowadays. Nevertheless, there are many questions in interpretation when one compares the documents and the building. That is, Cardinal Angelo Durini made a major modification in the 18th century, and further minor changes were made in the 19th century. Although these latter modifications did not alter the plan, they changed the distribution of rooms and masked both decoration and finishing. After over 20 years of neglect, Villa Mirabello is now close to being restored. Architects in charge ordered a preliminary set of diagnostics to assess damage and study the historical evolution of the building. Integration of IR thermography (IRT) and endoscopy allowed restorers to detect the structure's texture underneath the plaster, and to detect openings filled with masonry. Moreover, archive documents confirmed these results and, above all, defined a date for the use of specific building techniques. This research constitutes a reference for buildings set in the same time and location that do not have significant archival documentation. Active IRT provided useful information for structural assessment (such as location of arches, chimney stacks, different thickness of wall, wooden elements, voids, beams etc.) and for crack pattern evaluation. This information directs design professionals working on this conservation project, and helps define the costs of intervention.
Formation of Biocompatible Nanoparticles via the Self‐Assembly of Chitosan and Modified Lecithin
Authors: Chuah A.M. , Kuroiwa T. , Ichikawa S. , Kobayashi I. , Nakajima M.
Published: November 2008

ABSTRACT:  The formation of biocompatible nanoparticles via the self‐assembly of chitosan (CHI) and modified lecithin (ML) was studied. Stable nanoparticles in the size range of 123 to 350 nm were formed at over a wide molar mixing ratios of CHI/ML solutions (amino group/phosphate group) (NH3+/PO3−) and total polyelectrolyte (PE) concentrations (0.1 to 1 wt%) except at intermediate molar ratios when the surface charge was close to neutrality. Zeta‐potentials of the nanoparticles were found to be independent of the total PE concentrations. Nanoparticles exhibited excellent stability at over an extended pH (pHs 3 to 6) and ionic strength range (≤ 500 mM NaCl concentration). The particle size and zeta‐potential of the nanoparticles increased with the molecular weight of CHI. Transmission electron microscopy suggested that nanoparticles were generally spherical in shape with CHI constituting the exterior of its surface at high molar mixing ratios. Dextran‐fluorescein isothiocyanate, bovine serum albumin, and Coomassie brilliant blue as models of nonionic, positively and negatively charged compounds were encapsulated within the nanoparticles at between 8.7% and 62.7% efficiency. The ability of the nanoparticle suspensions to be converted to lyophilized powder or concentrated suspension was also demonstrated.
Smoke-free legislation and charitable gaming in Kentucky: Table 1
Authors: Pyles M K , Hahn E J
Published: November 2008

Objective:

To determine the effect of municipal smoke-free laws in Kentucky on gross and/or net revenues from charitable gaming activities. Between January 2000 and June 2007, 13 Kentucky communities implemented smoke-free legislation; only three specifically exempted charitable gaming facilities and compliance in several communities was not consistent. Kentucky is a tobacco-growing state that has the highest smoking rate in the United States.

Design:

A fixed-effects time series design to estimate the impact of municipal smoke-free laws on charitable gaming.

Setting:

13 Kentucky counties that implemented smoke-free laws during the study period of January 2000 through June 2007.

Subjects:

All charitable gaming facilities in 13 counties in which a smoke-free ordinance was enacted during the study period.

Main outcome measures:

Gross and net revenues from charitable gaming activities in each county for each quarter of the study period, obtained from the Kentucky Department of Charitable Gaming.

Results:

When controlling for economic variables, county-specific effects and time trends using a robust statistical framework, there was no significant relation between smoke-free laws and charitable gaming revenues. Municipal smoke-free legislation had no effect on charitable gaming revenues.

Conclusions:

No significant harm to charitable gaming revenues was associated with the smoke-free legislation during the 7.5-year study period, despite the fact that Kentucky is a tobacco-producing state with higher-than-average smoking rates.
Some characteristics of the sucrose uptake system of excised tomato roots
Authors: Chin C. , Lee M. , Weinstein M.
Published: November 2008

Uptake of sucrose by excised tomato roots showed saturation kinetics and could proceed against an internal sucrose concentration of approximately 0.046 M. It was inhibited by a number of compounds structurally related to sucrose and was largely but not totally dependent on respiration. It is concluded that sucrose was taken up mainly by an active process and to a lesser extent also by a passive process. Low pH markedly increased the uptake and sodium ions, and ouabain had no appreciable effect.
Influence of plankton mercury dynamics and trophic pathways on mercury concentrations of top predator fish of a mining-impacted reservoir
Authors: Stewart A. Robin , Saiki Michael K. , Kuwabara James S. , Alpers Charles N. , Marvin-DiPasquale Mark , Krabbenhoft David P.
Published: November 2008

Physical and biogeochemical characteristics of the aquatic environment that affect growth dynamics of phytoplankton and the zooplankton communities that depend on them may also affect uptake of methylmercury (MeHg) into the pelagic food web of oligotrophic reservoirs. We evaluated changes in the quality and quantity of suspended particulate material, zooplankton taxonomy, and MeHg concentrations coincident with seasonal changes in water storage of a mining-impacted reservoir in northern California, USA. MeHg concentrations in bulk zooplankton increased from 4 ng·g–1at low water to 77 ± 6.1 ng·g–1at high water and were positively correlated with cladoceran biomass (r = 0.66) and negatively correlated with rotifer biomass (r = –0.65). Stable isotope analysis revealed overall higher MeHg concentrations in the pelagic-based food web relative to the benthic-based food web. Statistically similar patterns of trophic enrichment of MeHg (slopes) for the pelagic and benthic food webs and slightly higher MeHg concentrations in zooplankton than in benthic invertebrates suggest that the difference in MeHg bioaccumulation among trophic pathways is set at the base of the food webs. These results suggest an important role for plankton dynamics in driving the MeHg content of zooplankton and ultimately MeHg bioaccumulation in top predators in pelagic-based food webs.
Habitat selection by black bears in an intensively logged boreal forest
Authors: Brodeur Vincent , Ouellet Jean-Pierre , Courtois Réhaume , Fortin Daniel
Published: November 2008

Extensive logging of the boreal forest rejuvenates landscapes once dominated by old-growth stands. As black bear ( Ursus americanus Pallas, 1780) fitness and behavior are known to be primarily related to the abundance of shade-intolerant soft mast species in northern forests, we hypothesized that logging will influence habitat and space use patterns of black bears. We used VHF telemetry on 12 female black bears in the Réserve faunique des Laurentides (Quebec, Canada) to investigate seasonal patterns of habitat selection in an exploited heterogeneous boreal landscape at different spatial scales. Habitat characterization based on seven forest cover types allowed us to compare the productivity of key forage species in various post-logging age classes. Regenerating stands (6–20 years old) had the uppermost ground vegetation cover, providing both the highest density and a high biomass of berries. Black bears preferred regenerating stands (6–20 years old) and avoided mature coniferous forests inside their home range. Home-range size was inversely related to the proportion of regenerating stands (6–20 years old). Intensive logging influenced black bear habitat and space use patterns, and presumably their population dynamics. An increase in the habitat quality of an opportunistic predator poses great concern for conservation, especially for forest-dwelling woodland caribou ( Rangifer tarandus caribou (Gmelin, 1788)).
NONSPHERICAL COLLAPSE OF TWO-FLUID STAR
Authors: GHOSH S. G.
Published: November 2008

We obtain the analog of collapsing Vaidya-like solution to include both a null fluid and a string fluid, with a linear equation of state (p⊥ = kρ), in nonspherical (plane symmetric and cylindrically symmetric) anti-de Sitter space–times. It turns out that the nonspherical collapse of two fluid in anti-de Sitter space–times, in accordance with cosmic censorship, proceed to form black holes, i.e. on naked singularity ever forms, in accordance with cosmic censorship, violating hoop conjecture.
Renal Excretion of Calcium and Magnesium during Acetazolamide or Parathyroid Hormone Administration in Dogs with Distal Blockade
Authors: Peraino R.A. , Rouse D. , Stinebaugh B.J. , Suki W.N.
Published: November 2008

Renal absorption of calcium and magnesium occurs in the proximal tubule, and at unknown site(s) beyond this segment. In the presence of blockade of Henle’s loop by ethacrynic acid, the excretion of calcium, magnesium and sodium in response to acetazolamide as compared to that with parathyroid hormone (PTH) was examined. Addition of acetazolamide to ethacrynic acid increased calcium and sodium excretion, but did not change magnesium excretion. In contrast, PTH added to ethacrynic acid did not change the excretion of any of the ions under investigation. Analysis of calcium and magnesium excretion as a function of sodium excretion, however, suggests that ethacrynic acid inhibited the effect of PTH to augment calcium absorption, but did not alter magnesium absorption, implying that the nephron site of PTH action to augment calcium absorption is the ascending limb of Henle’s loop and that to augment magnesium absorption resides beyond Henle’s loop.
Response of Dog Renal Na+, K+-ATPase to Insulin in vitro
Authors: Rivera Celso , Santos-Reyes H. , Martinez-Maldonado Manuel
Published: November 2008

The effect of insulin was studied in a kidney in vitro preparation to examine if it had a direct interaction with the Na+K+-ATPase system. Cortical and medullary microsomes obtained from dog kidney were utilized for the ATPase assay. Addition of 0.4 µg/ml of the hormone significantly increased the activity with 4 mM Na+:10 mM K+ (n = 8, p < 0.05) and 140 mM Na+:4 mM K+ (n = 8, p < 0.005) from basal (no insulin) activity. On the other hand, 20.8 µg/ml of insulin was needed to significantly increase the activity when 100 mM Na+: 10 mM K+ were present (n = 8, p < 0.05). The identity of the enzyme stimulated was corroborated by adding ouabain (10–3 M) and insulin (4.0 µg/ml) to the preparation; the glycoside was able to block all the stimulation; no change in Mg2+-ATPase was observed in any experiment.
Antiglomerular Basement Membrane Antibody and Microsphere Distribution in Rat Glomeruli
Authors: Trinh Trang Tan Marie-Marcelle , Bankir Lise , Diaz Mario , Grünfeld Jean-Pierre
Published: November 2008

Radiolabeled anti-glomerular basement membrane (AGBM) antibody was injected in rats and its distribution was studied in different glomerular populations by microdissection. It was compared with 15 µmmicrosphere distribution. AGBM antibody was not fully extracted in a single renal pass, precluding therefore its use as an indicator of intrarenal plasma flow. The amount of AGBM antibody fixed in juxtamedullary glomeruli was higher than in others. This result may be related to the larger capillary surface area in the former. In contrast, microspheres predominated in the superficial glomeruli. In addition to blood flow, rheologic factors probably lead to sphere accumulation in these glomeruli. Therefore, neither AGBM antibody nor microspheres accurately reflect glomerular blood flow distribution in the rat kidney.
Failure of Prostaglandin Synthesis Inhibitors and Urea to Increase Concentrating Ability in the Isolated Perfused Rat Kidney
Authors: Swartz Richard D. , Silva Patricio , Epstein Franklin H.
Published: November 2008

The isolated rat kidney perfused with a cell-free perfusion medium produces urine with a solute concentration at or below that of the perfusate. Vasopressin (Pitressin®), arginine vasopressin, DDAVP or dibutyryl cyclic AMP increased urine osmolality to a maximum of 20% above that of perfusate. The increase in urinary solute concentration was similar to the increase in solute content in the inner medulla of the perfused kidney. Inhibition of prostaglandin synthesis with indomethacin or acetyl salicylate decreased free water clearance slightly but did not increase urinary osmolality in response to antidiuretic hormone (ADH). Nor did inclusion of urea in the perfusate enhance the maximal response to ADH. It is concluded that the concentrating ability of the isolated perfused kidney is not improved by inhibition of prostaglandin synthesis and is limited by an inability to increase medullary solute concentration in the presence of the high perfusion flow rates which characterize this preparation.
Effect of Propranolol on Sodium Reabsorption and the Renal Circulation
Authors: Nomura Gakuji , Arai Shirõ , Uno Denji , Shimao Masato , Takata Masanobu , Takabatake Toshikazu , Hattori Nobu
Published: November 2008

The effects of intrarenal arterial (6.5 µg/kg/min) and intravenous (33 µg/kg/min) administration of propranolol on sodium excretion and renal hemodynamics were studied in anesthetized dogs. Heart rate, plasma renin activity and renal plasma flow were reduced by propranolol administered by either route. Blood pressure was reduced following intravenous infusion. Urinary sodium excretion was reduced by propranolol. This reduction was inversely correlated with the basal state of sodium excretion, and was also correlated with the reduction of glomerular filtration rate, effective renal plasma flow and blood pressure. We suggest that the antinatriuretic effect of propranolol is due to the reduction of glomerular filtration rate and of hydrostatic pressure in the proximal tubule, although additional factor(s) are not completely ruled out.
Effects of Inhibition of Phosphoenolpyruvate Carboxykinase on Ammonia Production by the Rat Kidney
Authors: Bennett Franklyn I. , Alleyne G.A.O.
Published: November 2008

Phosphoenolpyruvate carboxykinase (PEPCK) in the renal cortex shows the expected increase in activity but oxal acetate decarboxylase and malic enzyme, two other enzymes capable of providing precursors for use in the total oxidation of glutamine by the kidney, showed no change in their activity as a result of metabolic acidosis in rats. 3-Mercaptopicolinic acid, a substance which inhibits PEPCK, caused a 23% decrease in the oxidation of glutamine to CO2 by kidney cortical slices in vitro. 3-Mercaptopicolinic acid in vivo had anomalous effects on gluconeogenesis but consistently inhibited ammoniagenesis by kidneys of normal as well as acidotic rats.
Effect of Indomethacin on Changes of Acute Ureteral Pressure Elevation in the Dog
Authors: Edwards G.A. , Suki W.N.
Published: November 2008

The effects of indomethacin on hemodynamic and excretory alterations produced by acute ureteral obstruction were investigated in anesthetized dogs by means of radiolabeled microspheres and clearance techniques. Renal blood flow in untreated animals increased by 40 ± 12% with acute ureteral pressure elevation in comparison to the contralateral unobstructed kidney. This increase was only 7 ± 3% (p < 0.01) in indomethacin-treated animals. Likewise untreated animals exhibited a redistribution of blood flow from superficial to deeper cortex while indomethacin-treated animals showed no redistribution (p < 0.025). However, indomethacin treatment did not alter changes in glomrular filtration rate or electrolyte excretion of acute obstruction. These results suggest that prostaglandins or closely related compounds are involved in the hemodynamic changes of acute obstruction, but that they do not play an important role in the determination of glomerular filtration rate or electrolyte excretion.
Relationship between Proximal Tubule Total CO2 and Phosphate Reabsorption in Acute and Chronic PTX Rats
Authors: Kuroda Shigeomi , Aynedjian Hagop S. , Zilenovski Alexandre M. , Bank David E. , Bank Norman
Published: November 2008

The effect of NaHCO3 infusion on phosphate reabsorption by the proximal convoluted tubule was studied in acute and chronic PTX rats. Either hypertonic NaHCO3 or NaCl was infused intravenously. Proximal fluid and phosphate reabsorption were measured with 3H-inulin and 32PO4, respectively. In acute PTX rats, the fraction of filtered 32PO4 remaining in the proximal lumen was 5.9% during NaCl infusion and 23% during NaHCO3 infusion (p < 0.001). In the chronic PTX rats, the fraction of filtered 32PO4 remaining in the proximal lumen was 24% during NaCl infusion and 38% during NaHCO2 infusion (p < 0.001). Phosphate reabsorption per unit GFR was reduced by NaHCO2infusion in both acute and chronic PTX rats. A linear relationship was found between tubular fluid total CO2 and the fraction of 32PO4 remaining in the tubular lumen. The findings indicate that NaHCO3 infusion inhibits phosphate reabsorption in the proximal convoluted tubule by a mechanism not dependent on PTH or volume expansion, but apparently correlated with intraluminal CO2.
Urinary Kallikrein Excretion after Renal Sympathectomy in the Rat
Authors: Fejes-Tóth Géza , Szénási Gábor , Zahajszky Tibor , Takács Lajos
Published: November 2008

Renal excretion of sodium and water as well as urinary kallikrein excretion were measured after acute and chronic renal denervation in the anaesthetized rat. Although a significant denervation diuresis and natriuresis was observed in all experiments, kallikrein excretion rates in the intact and denervated kidneys were similar. The results seem to indicate that the kallikrein-kinin system is not involved in the denervation phenomenon and that basal kallikrein secretion is not influenced by the sympathetic nervous system.
Renal Corpuscle Development in the Dog
Authors: Gattone II Vincent H. , Johnson Michael L. , Morse Dennis E.
Published: November 2008

Renal vesicle formation and glomerular development were studied in the 44-day dog fetus with the use of the scanning electron microscope. In the early stages of glomerular development the luminal aspect of the columnar glomerular epithelium shows a cobblestone appearance with sparse microvilli and occasional cilia. Marginal club-shaped processes are the earliest sign of prodocyte process development. These interdigitate with neighboring cell processes and elongate before developing definitve foot processes. Glomerular epithelial differentiation is uneven and multifocal, but once started, proceeds rapidly. The capsular epithelium progresses from cuboidal (in the vesicular stages) to squamous (in the mature glomerulus) with the area adjacent to the proximal convoluted tubule being the last area to differentiate fully.
Prostaglandins E2 and F2αand Urinary Sodium Excretion in Isolated Dog Kidney
Authors: Vanherweghem Jean-Louis , Guerisse Patrick , Ducobu Jean , d’Hollander Alain , Kaivez Etienne
Published: November 2008

The role of prostaglandins (PG) E2 and F2α on urinary Na excretion was studied in paired isolated dog kidneys which were blood perfused on Nizet’s oxygenators. In group 1 experiments, lysine acetylsalicylate (LAS), a PG- synthetase inhibitor, was added to the blood perfusing one kidney, the contralateral paired kidney being observed as control. In group 2 and in group 3 experiments, both kidneys were treated with LAS but PGE2 (group 2) or PGF2α (group 3) was added to the experimental kidneys. In group 1, LAS inhibited the spontaneous vasodilatation characterizing the isolated dog kidney perfusion while PGE2 or PGF2α addition to LAS-treated kidneys restored vasodilatation. No significant difference in glomerular filtration rate between experimental and control kidneys was observed in any of the three groups of experiments. In group 1, LAS reduced tubular Na reabsorption rate, presumably at a distal site (clearance studies). PGF2α reduced Na excretion rate in LAS-treated kidneys of group 3 while PGE2 increased it in similar conditions (group 2). In group 1, LAS reduced PG levels in the perfusing blood mainly by decreasing PGF2α concentrations. A significant correlation was demonstrated between tubular Na reabsorption rate, expressed as a fraction of Na filtered load, and PGF2α levels. In the isolated dog kidney, Na tubular transport is thus inhibited by PGE2 (hemodynamic or direct tubular effect) while it is enhanced by PGF2α (direct tubular effect).
Immunochemical and Morphological Difference between the Immature and Mature Glomerular Basement Membrane in the Rat
Authors: Lubec G. , Kitz K. , Adamiker D.
Published: November 2008

Glomerular basement membranes (GBM) were isolated from the kidneys of adult and newborn Sprague-Dawley rats. The isolated GBM were degraded by trypsin and the degradation products were characterized by immunoelectrophoresis applying an anti-rat GBM serum from the rabbit. GBM of the adult rat showed two precipitation lines, GBM from the newborn rat presented a single line in immunoelectrophoretical characterization. GBM of 6 adult and 6 newborn rats were measured on electron microscopy revealing significant differences of thickness. The mean thickness of the adult rat GBM was 2,060 Å (2.06 × 10-7 m), the SD was ± 83 Å; of the newborn rat mean GBM was 1,500 Å (1.5 × 10-7 m), the SD was ± 71 Å. Our results indicate that the immature GBM differs from the mature structure qualitatively and quantitatively.
Acid Mucopolysaccharide and One of Its Glomerular Degrading Enzymes β-Glucuronidase in Experimental and Human Glomerulonephritis
Authors: Matsuo Eiich , Yamada Kazuaki
Published: November 2008

In 1962, when the immune complex in nephritic glomerular basement membrane (GBM) was clarified as being a type of GBM thickening, Amon and Gayer reported a different type of thickening in the rabbit administered hyaluronidase (an enzyme to degrade hyaluronic acid) and named it ‘herniation’ of the GBM. As we have been interested for a long time in the disappearance of normally present nonsulfated AMPS, presumably hyaluronic acid (HA), from the glomeruli in humans and experimental animals with chronic glomerulonephritis, we wanted to observe the activity of the enzyme in these conditions. Since a suitable histochemical method for the precise evaluation of hyaluronidase is unavailable, we instead chose β-glucuronidase(β-Gase), which is also an enzyme which degrades HA. The principal study was performed by means of light- and electron-microscopic histochemistry of chronic glomerulonephritis produced experimentally in rats and compared the obtained results to those in human chronic glomerulonephritis. The high activity of β-Gase with a coincidental decrease of AMPS in the glomeruli was observed both in experimental and human chronic glomerulonephritis. The herniation type GBM thickening in the rat was coincidental with the enzyme localization with the disappearance of AMPS from foot processes of epithelial cells overlaying the lesion. The results might suggest the key role of β-Gase in the deformation of GBM in chronic glomerulonephritis in general.
Glomerular Basement Membrane Injury by Neutrophil and Monocyte Neutral Proteinases
Authors: Davies Malcolm , Coles Gerald A. , Hughes Kelvin T.
Published: November 2008

Human peripheral blood leucocytes known to be present in the glomeruli of patients with certain forms of clinical glomerulonephritis have been investigated for their proteinase content and their ability to degrade glomerular basement membrane (GBM). Polymorphonuclear leucocytes (PMN) and monocytes, but not lymphocytes, contain neutral proteinases which extensively degrade GBM at physiological pH. Inhibitor studies indicate that the enzymes responsible are serine-type proteinases. The relative susceptibilities of the GBM to proteolytic attack showed that the monocyte preparation was considerably more active than the PMN neutral proteinases. The monocyte preparation also showed the ability to degrade GBM at acid pH. Lymphocytes had no effect on GBM either at acid or neutral pH. The possibility that the lysosomal proteinase of monocytes and PMNs are implicated in the damage to the GBM in glomerulonephritis is suggested.
Glomerular Permeability
Authors: Cavallo Tito
Published: November 2008

To study alterations in glomerular permeability and their relation to immune deposits, anionic and cationic ferritins were systemically injected in immunosuppressed or untreated mice with lupus nephritis. Kidneys were studied by light, immunofluorescence and electron microscopy. In untreated mice with membranous and proliferative glomerulonephritis, ultrastructural analyses of tracer molecules in the capillary wall indicated that deposition of immune complexes (a) resulted in a focal, not generalized, alteration in the glomerular permeability properties; (b) induced disruption of size- and charge-based barriers at the vicinity of such immune deposits, and (c) induced leak of anionic protein, predominantly via residual slit pores, into the urinary space. When mice with immune complex disease were immunosuppressed with cyclophosphamide or methylprednisolone for 90 days, immune complexes were confined to the mesangium and glomerular structure and barrier (size- and charge-based) function were preserved.
Preparation and Histoarchitecture of Ultrastructurally Pure Glomerular Basement Membrane
Authors: Carlson Edward C. , Kenney Cristina
Published: November 2008

Our recent morphological studies showed that basement membranes isolated from renal tubules tended to collapse and form folded sheets while glomerular basement membranes were more resilient. In an effort to study the shapes of various isolated basement membranes in undissociated tissues, a method was developed to remove all cellular elements and leave the extracellular matrix and associated basement membranes intact. Accordingly, transplant quality human kidneys were harvested, perfused with Collin’s medium and transported to the laboratory on ice. The renal cortex was then peeled away by blunt dissection, further minced to 2 mm3 and placed in 1 mM EDTA (with gentle intermittent stirring) for 72 h at 4°C. Solubilization of cellular materials was carried out by successive washings with 3% Triton X-100, 0.025% DNAse and 1–4% sodium deoxycholate (all with gentle stirring or shaking at 22 °C). Each solution contained 0.1% sodium azide. At the level of fine structure, glomerular, tubular, Bowman’s capsular and peritubular capillary basement membranes all maintained their respective shapes and did not collapse. Glomerular basement membrane was particularly striking in this regard and exhibited an open, lobulated form that closely resembled its in vivo histoarchitecture. Moreover, when the acellular tissue blocks were prepared for scanning electron microscopic observation, the glomerular basement membranes exposed at the surface of the block showed a remarkable structural rigidity. These basement membranes were free-standing, convoluted electron-dense sheets, continuous with highly folded central mesangial regions. It seems significant that glomerular basement membranes maintain their in vivo conformation irrespective of the presence of other extracellular matrix components while removal of these materials by organ subfractionation results in folding and general shapelessness of tubular basement membrane. It is possible that in addition to its unique role in filtration, glomerular basement membrane may also serve to preserve glomerular shape, regardless of changing cell populations or alterations in hydrostatic pressures.
Murine Autoimmune Interstitial Nephritis and Associated Antigen: Purification of a Soluble Tubular Basement Membrane Antigen from Mice Kidneys
Authors: Wakashin Masafumi , Wakashin Yoko , Ueda Shiro , Takei Izumi , Mori Yoshio , Mori Teruo , Iesato Kenji , Okuda Kunio
Published: November 2008

A soluble tubular basement membrane (TBM) antigen has been purified from murine kidneys. The isolated fibers were trypsinized and subjected to zone electrophoresis, Sephadex G-200 gel filtration, and DEAE-cellulose chromatography eluted with linear NaCl concentration gradient while monitoring the TBM antigen activity with specific antihuman TBM antigen. The molecular weight of TBM antigen was estimated to be 30,000 daltons by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The purified TBM antigen gave a single precipitin line against the specific antiserum and cross-reacted with the TBM antigen similarly purified from other animals such as goat, guinea pig and also with human TBM antigen in an immunodiffusion plate. BALB/c, C3H/He and C57BL/6 mice were immunized twice at 2 weeks’ interval with the TBM antigen and adjuvant. Histologically typical interstitial nephritis occurred in BALB/c mice, whereas no nephritis developed in other strains of mice. The inflammatory changes were characterized by intense mononuclear cell infiltration, tubular destruction, and interstitial and periglomerular fibrosis. The serum-stained basement membrane of normal tubules and Bowman’s capsules, and no antiglomerular basement membrane activity was detectable in the serum by immunofluorescence. This system provides a simple and useful model of interstitial nephritis in mice produced with a purified TBM antigen.