bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of worldwide regulatory guidance for surface soil contamination
Authors: Jennings Aaron A.
Published: November 2008

Regulations are emerging worldwide to address surface soil contamination. Many of these use regulatory guidance values (RGVs) to specify concentrations above which action is required. However, because so many independent jurisdictions develop these values, the results are highly variable. Recent studies have demonstrated that the RGVs used by US states vary by several orders of magnitude. This manuscript presents results from an effort that identified 62 surface soil RGV datasets containing 3574 values from 31 other nations and compiled them into a database titled International Surface Soil Regulatory Guidance Values (IS2RGV). Analysis indicates that there are also orders of magnitude variability in the RGVs used worldwide, and that this variability has much in common with US state RGV variability. Results are presented for the 30 most frequently regulated organic, 20 most frequently regulated inorganic, and all regulated element contaminants. Trichloroethylene, cyanide, and mercury are used to illustrate how worldwide RGV variability compares with that of US states, and how data may be commingled to help identify emerging consensuses.
Evaluation of photoreactivation of Escherichia coli and enterococci after UV disinfection of municipal wastewater
Authors: Locas Annie , Demers Josée , Payment Pierre
Published: November 2008

Because chlorine disinfection is not permitted in the province of Quebec, wastewater disinfection by ultraviolet (UV) light has been used for years in wastewater treatment plants. Thermotolerant coliforms discharge criteria are set for each plant and are adjusted by a factor of 1 log to compensate for photoreactivation in UV-disinfected effluents. The current study evaluated levels of Escherichia coli and enterococci photoreactivation from disinfected wastewater under varying temperature, visible light, and type of UV lamps. Escherichia coli photoreactivation increased significantly after exposure to 5600 lx compared with 1600 lx of visible light. This increase was significantly higher in warm water (25 °C) than cold water (4 °C). The level of photoreactivation of E. coli was also higher after wastewater disinfection by low-pressure UV lamps as opposed to medium-pressure UV lamps. Enterococci, however, were not photoreactivated under any test conditions. This result suggests that enterococci could be a better indicator than thermotolerant coliforms or E. coli. The use of enterococci would also eliminate the requirement to set different discharge criteria based on disinfection type (UV or chemical) and would also provide a better assessment of treatment efficiency for more resistant microorganisms.
Differential survival of allosperm by location within the female storage organ of the snail Cornu aspersum
Authors: Chase Ronald , Darbyson Emily
Published: November 2008

The sperm storage organ of terrestrial gastropod molluscs is implicated in sexual selection because it has a complex structure and it functions in a context of intense sperm competition. Received sperm are stored in spermathecal tubules. In our sample using the brown garden snail ( Cornu aspersum (Müller, 1774)) (n = 58), the mean number of tubules per animal was 16, with lengths ranging from ≤40 to 2480 μm. A hereditary influence on tubule number was indicated by clutch-dependent variations. From histological sections, we counted the spermatozoa that were present in the tubules of ex-virgin snails 1, 2, 4, and 8 weeks after mating (n = 40). Sperm were distributed, on average, across 75% of the tubules in individual snails, thus contradicting one proposed mechanism for cryptic female choice. The total number of sperm declined 66% over 8 weeks, with the largest losses incurred by sperm in the lumens of the tubules and sperm gathered in clusters. By contrast, in the same period, the numbers of sperm that were in contact with the walls of the tubules remained relatively stable. These data imply that sperm survive best when attached to the epithelial wall, either because they derive nutrition from the epithelium or because they use the epithelium as an anchor.
GLUON SELF-INTERACTION IN THE POSITION SPACE IN LANDAU GAUGE
Authors: CVETIČ GORAZD , KONDRASHUK IGOR
Published: November 2008

We propose a method to treat the three-gluon self-interaction vertex in the position space in D = 4 - 2∊ dimensions. As an example, we calculate a two-loop contribution to auxiliary Lcc vertex in the Landau gauge which contains the three-gluon vertex for SU (N) Yang–Mills theory. We represent the integral expression as a sum of separate contributions so that each of the contributions is a double finite integral or single integral (singular or finite) in the position space. In each double finite integral, we use the freedom to shift exponents in powers in the denominator of integrands by some multiples of ∊, in order to perform at least one of the integrations by the uniqueness technique without corrupting the first term of the decomposition in ∊.
DENSITY OSCILLATION FROM NANOSCALE TO MACROSCALE
Authors: CHEN X. Y. , LIU Y. , YANG J. M.
Published: November 2008

The effect of channel width on the density structure of confined fluid in the nano-/micro-channels is examined by equilibrium molecular dynamics (EMD) simulation. It was found that the density oscillation occurs near the wall in both cases of the macroscale or nanoscale confined flow. There exists a threshold channel width L threshold , when channel width HL threshold , L threshold is constant and about 5–6 molecular diameter long, and the density becomes uniform beyond this threshold layer. A newly defined ch number may serve to be the parameter to compare similarity in the micro-/nano-scale channel flow. Moreover, the effect of the density oscillation on fluid mass flux rate is examined quantitatively. The result shows that the effect should be considered when the channel width is below 5 molecular diameter.
Reversibility of Lithium-Induced Impairment of Renal Concentrating Ability in Rats
Authors: Christensen Sten , Hansen Bent
Published: November 2008

Male Wistar rats were treated with lithium added to their food for 11 weeks followed by a withdrawal period of 4 weeks. Urine flow and osmolality were recorded daily. Renal concentrating ability was evaluated from the maximal urine osmolality recorded by the DDAVP test (5 ng/kg s.c.) and dehydration test (28 h or until 8% loss of body weight) after lithium treatment for 1,3 and 9 weeks, and 1, 2, 3 and 4 weeks after withdrawal of lithium. During lithium treatment, the rats developed massive polyuria with severe impairment of renal concentrating ability. After withdrawal of lithium, urine flow and osmolality and renal concentrating ability were reversed to control levels within 2-3 weeks. There was a highly significant correlation between the results obtained with the two tests for renal concentrating ability. Lithium treatment did not cause irreversible changes of endogenous creatinine clearance or plasma creatinine concentration. It is concluded that the impairment of renal concentrating ability caused by prolonged lithium administration is a reversible condition.
Effect of Early Pregnancy on Glomerular Filtration Rate and Plasma Volume in the Rat
Authors: Baylis C.
Published: November 2008

Whole kidney and micropuncture techniques were employed to investigate renal function in early pregnant (day 6 of gestation) and virgin Munich-Wistar rats. No changes were seen in glomerular filtration rate (GFR) or in any of its determinants at day 6 of pregnancy. In separate studies, the measurement of plasma volume showed that whereas a marked expansion had occurred by day 12 of pregnancy only slight increases in plasma volume were apparent at day 6. These findings, together with evidence from a previous study which indicated that a significant increase had occurred in GFR by day 12 of pregnancy, suggest a relationship between GFR and plasma volume in the pregnant rat.
Variations in Chemical Composition of Human Glomerular and Tubular Basement Membranes with Age and Disease
Authors: Langeveld J.P.M. , Veerkamp J.H. , Monnens L.A.H.
Published: November 2008

A graded sieving procedure was used to isolate glomeruli and tubules from renal cortex of men of premature age up to 80 years and of 4 patients suffering from Zellweger syndrome, congenital nephrotic syndrome, polycystic renal disease or diabetes mellitus. Glomerular and tubular basement membranes (GBM and TBM, respectively) were obtained with a detergent procedure. Purity of basement membrane preparations was controlled with light and electron microscopy and by estimating total phosphorus content. Amino acid and carbohydrate composition of the basement membranes were determined and statistically evaluated. Comparison of GBM and TBM from the same kidneys showed at all ages that GBM contains more 3-hydroxyproline, neuraminic acids and mannose. These differences may contribute to the different immunogenic properties of the two basement membranes reported in the literature. Significant changes with age in the chemical composition were found, suggesting that the proportion of collagenous peptide moieties increases and that of noncollagenous peptide moieties decreases with age in both GBM and TBM. In addition, the hydroxylation grade of proline and lysine increases significantly with age reaching an adult level for GBM after 4–6 months of age and for TBM at late childhood. The age-related changes in basement membrane composition may influence functional properties of these extracellular renal structures. The chemical composition of GBM and/or TBM of the 4 patients showed some differences in comparison to control preparations from persons with ages approximating that of the patients.
Glomerular Pyrimidine Metabolism in Experimental Diabetic Nephropathy
Authors: Cortes P. , Dumler F. , Levin N.W. , Venkatachalam K.K. , Spargo B.H. , Goldman J.
Published: November 2008

Glomerular uracil nucleotide metabolism was studied in vivo in control and diabetic rats 48 h after the injection of streptozotocin. The animals were infused for 2 h with 3H-orotate and the fraction of infused dpm incorporated into glomerular uracil nucleotides and RNA/mg of glomerular DNA was calculated. Diabetic glomeruli showed an increase in RNA/DNA compared to controls (p < 0.05) and a greater incorporation of 3H-orotate into uracil nucleotides and RNA. These changes were reversed by insulin therapy. In separate experiments the renal cortical uracil nucleotide pool was expanded by feeding chow supplemented with 0.5% orotate to rats for 6 months. Normal animals fed orotate developed significant glomerular basement membrane thickening (p < 0.01) when compared to age-matched controls, which was morphologically indistinguishable from that of diabetics. Orotate feeding also produced further basement membrane thickening in diabetic rats. These results suggest that early diabetes is characterized by an increase in glomerular uracil nucleotides, and that chronic expansion of the uracil nucleotide pool is associated with glomerular basement membrane thickening.
Evidence that Kidney Lysosomal Proteinases Degrade the Collagen of Glomerular Basement Membrane
Authors: Davies Malcolm , Hughes Kelvin T. , Thomas Gareth J.
Published: November 2008

Three thiol-dependent tissue proteinases have been isolated from human kidney cortex by methods using detergent extraction, gel chromatography, affinity chromatography and separation by ion-exchange. The properties of each enzyme towards several chromogenic low molecular weight substrates, azocasein and collagen indicate that they are similar to cathepsins B, H and L. All three enzymes degrade glomerular basement membrane at acid pH. Cathepsin B and L were particularly active against glomerular basement membrane. It has been demonstrated that in liver these enzymes exist together in lysosomes. These properties indicate that the kidney thiol proteinases may be an important factor in the turnover of glomerular basement membrane.
Human Basement Membrane Antigens from Lung, Placenta and Kidney
Authors: Bray Bonnie Anderson , Turino Gerard M. , Mandl Ines
Published: November 2008

Three human basement membranes, glomerular basement membrane (GBM) from renal cortex, alveolar basement membrane (ABM) from lung parenchyma and trophoblast basement membrane (TBM) from the terminal villi of placenta have been isolated by sieving and sonication techniques. Canine GBM and ABM were also prepared. There were marked differences among the membranes from human tissues. Compared to GBM, TBM had very little collagen but contained high concentrations of charged amino acids. ABM was intermediate in composition between GBM and TBM and contained desmosine and isodesmosine indicative of the presence of elastin. Canine ABM (c-ABM) did not contain desmosine or isodesmosine. In the canine system an antigen was detected in ABM which was not present in GBM. The membrane preparations were analyzed for fibronectin content using a specific antiserum to fibronectin. This glycoprotein could not be detected in GBM whereas it was present in ABM in amounts up to 0.8% and in TBM in amounts as high as 7.2%. All the membranes induced the formation of precipitating antibodies in rabbits. Soluble material obtained from the membranes by alkali extraction, reduction of disulfide bonds, enzymatic digestion with elastase, plasmin or collagenase provided immunologically reactive fragments. These soluble fragments gave reactions of identity among the three basement membranes in immunodiffusion reactions in gels with antisera raised to all three BMs. The finding that plasmin digests basement membranes suggests that it may play a role in connective tissue remodeling. The fact that elastase degrades basement membranes provides an endogenous system for injury which may be triggered by infections.
Rabbit Glomerular and Tubular Basement Membranes: Morphology and Differential Solubilization
Authors: Brendel Klaus , Duhamel Raymond C. , Spall Richard D. , Meezan Elias
Published: November 2008

Rabbit glomeruli and tubules were obtained by retrograde perfusion of magnetite into the lower aorta as previously described for the isolation of rat glomeruli. In addition, an alternative method of separating rabbit glomerular and tubular basement membranes from a single renal cortex preparation was developed. These preparations, which represent the Triton X-100-insoluble material, were extracted in sequence with deoxycholate, dodecyl sulfate in the presence and absence of 2-mercaptoethanol at 8 °C and again in the latter at 100 °C. The polypeptides solubilized at each step of this sequence were characterized by electrophoresis. The final extract consisted almost exclusively of red-staining, presumably collagenous bands, while the earlier extracts consisted of blue-staining, presumably noncollagenous bands. No significant differences were found between the glomerular and tubular basement membrane extracts.
Isolation and Characterization of Rat Renal Glomerular Cells in vitro
Authors: Foidart J.B. , Goffinet G. , Dubois C. , Dechenne C. , Mahieu P.R.
Published: November 2008

Glomerular tufts were isolated from normal rat kidneys and were cultivated in RPMI1640 medium supplemented with 15% fetal bovine serum. Studies on DNA synthesis demonstrated two peaks (A and B) of cell division. The cells of peak A grew as a monolayer until confluency, exhibited many junctional complexes and microvilli. They were very susceptible to the aminonucleoside of puromycin, as glomerular epithelial cells in vivo. They did not contain many bundles of intracellular microfilaments and were not stained by an anti-factor VIII serum. The cells of peak B formed both monolayered sheets and multilayered bands, exhibited no junctional complexes, but contained large bundles of intracellular fibrillar structures, which were strongly stained by an antimyosin antiserum. They were not stained by an anti-factor VIII antiserum. The B cells exhibited a contractile activity in response to 10-9M angiotensin II and were very susceptible to mitomycin C treatment, as glomerular mesangial cells in vivo. They synthesized large amounts of prostaglandins (mainly PGE2). The data suggest that the A cells are visceral epithelial cells, and that the B cells are smooth muscle-like cells derived from the glomerular mesangium.
Biological Thixotropy of Glomerular Basement Membrane and the Implications of Thioxotropy in Explaining Basement Membrane Permeability
Authors: Simpson L.O.
Published: November 2008

Glomerular basement membranes (GBMs) are considered to exhibit the characteristics of biological thixotropic systems, and because of this GBM permeability is determined by intravascular pressure. The significance of pressure as the major determinant of GBM permeability is discussed. Factors leading to GBM permeability to albumin following interruption of renal blood flow are examined, and a possible explanation for the phenomenon is proposed.
Anionic Binding Sites in the Glomerular Basement Membrane: Possible Role in the Pathogenesis of Immune Complex Glomerulonephritis
Authors: Batsford S. , Oite T. , Takamiya H. , Vogt A.
Published: November 2008

This paper details the ways in which the anionic sites of the GBM could be involved in immune complex deposition. Experiments were performed with chemically cationised proteins to test the hypotheses proposed. The most detailed investigations were concerned with the role of basic (cationic) antigen as a planted antigen, leading to in situ immune complex formation. A model was developed where it was possible to induce marked proteinuria following a single injection of small quantities of cationised human IgG or ferritin.
Glomerular Basement Membrane Changes in Nonhereditary Glomerular Diseases
Authors: Gubler M.C. , Levy M. , Naizot C. , Habib R.
Published: November 2008

Some examples of glomerular lesions developing in different types of nonhereditary glomerular diseases have been described. In most of them, secondary glomerular basement membrane changes are important factors in the development and progression of the glomerular lesions. When severe, they initiate irreversible glomerular scar formation.
Impaired Natriuresis after Volume Expansion in the Aged Rat
Authors: Bengele Howard H. , Mathias Robert S. , Alexander Edward A.
Published: November 2008

These experiments were designed to compare the natriuretic ability of old (age 22–24 months) and young (4–6 months) rats after volume expansion. No difference in extracellular fluid volume was noted as estimated by inulin space; old 18.8 ± 0.6% and young 18.2 ± 0.7% of body weight. Standard clearance techniques were utilized in unanesthetized animals. The fraction of infused sodium excreted during and after expansion with isotonic saline equal to 7% BW was statistically lower in the old group 53 ± 2 vs. 68 ± 3% (p < 0.01). Similar measurements were made during the infusion of whole blood equal to 2.3% BW. Again the old rats excreted a significantly lower fraction of the infused Na, 55 + 10 vs. young 112 ± 12%. These differences do not appear to be explained by changes in glomerular filtration rate, blood pressure, hematocrit or serum protein concentration. We conclude that aged rats have an impaired ability to excrete sodium with volume expansion but the mechanism for this defect is yet to be determined.
Inhibition of Renal Creatinine Secretion by Cimetidine in Humans
Authors: Burgess Ellen , Blair Andrew , Krichman Kenneth , Cutler Ralph E.
Published: November 2008

The renal clearance of inulin (Clin), 14C-creatinine (Cl14C.cr) and endogenous creatinine (Clcr) were measured in 6 healthy subjects before and after a single intravenous bolus of cimetidine (5 mg/kg). The initial Cli4C.cr/Clin ratio (mean ± SD) was 1.68 ± 0.17; this fell to a nadir of 1.35 ± 0.18 soon after cimetidine was infused and rose again as the drug was excreted. This is the first cationic drug to show substantial inhibition of tubular secretion of creatinine in humans.
The Influence of Indomethacin and Possible Role of Prostaglandins on Calcium Renal Excretion
Authors: Colette C. , Aguirre L. , Monnier L. , Mimran A.
Published: November 2008

Our aim was to evaluate the possible role of prostaglandins (PG) on renal calcium excretion in humans through the PG inhibitory effects of indomethacin. Renal calcium excretion was evaluated by a technique of impulse analysis which gives a function W(t) specific of the tubular calcium transport. Several parameters were derived from this function: (1) the fractional excretion of filtered calcium as % of total dose (FECa % TD); (2) the peak excretion rate, and (3) the mean transit time (MTT, min). The aforementioned parameters were determined in 7 healthy subjects in basal conditions and again after 10 days of treatment with 100 mg indomethacin daily. FECa was significantly (p < 0.02) higher with indomethacin (8.18 ± 0.97) than under basal conditions (5.02 ± 0.57). The peak excretion rate and MTT remained unchanged after indomethacin. These results indicate that indomethacin increases renal calcium excretion. As indomethacin did not produce any significant change in glomerular filtration rate (125 ± 7 ml/min before vs. 129 ± 9 ml/min after) one can assume that PG play a role in tubular calcium reabsorption. However, the mechanism remains to be elucidated: direct action or mediated through the cyclic AMP system.
Bicarbonate Concentrations in the Renal Cortex
Authors: Gamble, Jr. James L. , Skoff Anne M.
Published: November 2008

Total CO2 (CO2+HCO-3) was measured in alkaline extracts of quickly frozen rat renal cortex. The mean concentration calculated for tissue water was 18.7 ± SD 1.6 mEq/1 (n=10) when that measured in plasma water was 23.5 ± 1.7. In other experiments (n=6–10), the mean concentration in tissue water increased to 28.3 mEq/1 after the animals were treated with benzolamide to inhibit carbonic anhydrase and to 38.1 mEq/1 after they were infused with NaHCO3. On the other hand, the tissue concentration decreased to 14–15 mEq/1 when they were hyperventilated or infused with HC1. Calculations based on published micropuncture data indicate that the usual intracellular concentration is 20–25 mEq/1 or about twice that usually reported for skeletal muscle; and in contrast to muscle, the findings are suggestive of large variations in metabolic disorders.
Plasma Bicarbonate and CO2 Tension
Authors: Fulop Milford , Fulop Michael
Published: November 2008

The relation between plasma bicarbonate concentration ([HCO-3]) and C02 tension (PCO2) in normal subjects was studied by Madias et al. They calculated these values from measurements of plasma total CO2 content and blood pH using the Henderson-Hasselbalch equation. We calculated the relation between [HCO-3] and PCO2 using values obtained not from measurements, but from total CO2 and pH values chosen either randomly or uniformly within the ranges found by Madias et al. Both approaches yielded relations between [HCO-3] and PCO2 very similar to those found by Madias et al. Our findings indicate that the equation relating those variables depends mainly on the ranges of total CO2 and pH values, and how [HCO-3] and P CO2 are inherently related by the Henderson-Hasselbalch equation. Therefore, the mathematical relation between those variables should not be used to draw inferences about the physiological processes that relate them.
Renal Handling of Fluoride in Healthy Man
Authors: Schiffl H. , Binswanger U.
Published: November 2008

In 10 healthy volunteers the renal handling of fluoride was investigated by standard clearance techniques. The renal fluoride clearance ranged from 12.4 to 71.4 ml/ min, values consistently less than corresponding glomerular filtration rates as estimated by the 51Cr-EDTA clearance. The fractional excretion of fluoride correlated with fractional water reabsorption (r = 0.87). It is concluded that renal fluoride excretion is characterized by free filtration at the glomeruli and subsequent net tubular back diffusion.
The Effect of Hemorrhagic Hypotension on Total and Local Renal Blood Flow in the Rat
Authors: Hope Arvid , Tyssebotn Ingvald , Clausén Gunnar
Published: November 2008

The effect of hemorrhagic hypotension (HH) on local and total renal blood flow was studied in rats. Cortical blood flow, measured as H2 gas clearance, was determined before and during HH with a mean arterial blood pressure of 50 mm Hg. During the initial 10-5 min of bleeding renal cortical vascular resistance was unchanged, and total renal blood flow autoregulatory ability was abolished. Cortical vascular resistance thereafter increased steadily to twice the control level after 90 min of HH. At this time, retransfusion of the shed blood improved cortical blood flow due to increased arterial blood pressure, not to reduced cortical vascular resistance. In a second group, total and local renal blood flows were obtained from 125I-iodoantipyrine uptake rate after 2 h of HH with arterial blood pressure maintained at 50 mm Hg. Total renal blood flow was reduced to 20% of control with no change in blood flow distribution between outer and inner cortical or medullary zones. Both cortical blood flow and intrazonal local renal blood flow heterogeneity had increased at the end of the HH period. However, ischemic and extremely low flow sectors comprising cortex and outer medulla were observed only in 1 of the 10 kidneys studied with the 125I-iodoantipyrine technique. In only 1 of 8 animals studied with the H2 gas method were intermittent sudden changes in cortical blood flow observed during HH. Since hematocrit tended to fall during HH, these observations support the concept that local flow intermittence is predominately associated with high hematocrit shocks.
Effect of Intraluminal PGE2 and Systemic Indomethacin on Sodium Chloride Transport in the Rat Distal Tubule
Authors: Kunau, Jr. R.T. , Geiger C. , Hull J. , Wong-Garcia R.M.
Published: November 2008

The present studies examined the effect of intraluminal PGE2 and systemic indomethacin on sodium chloride transport in the superficial distal tubule of the rat nephron. Controlled quantities of sodium chloride delivery to this segment were provided by in vivo microperfusion techniques. Neither 2µM intraluminal PGE2, 2 mg/kg body weight indomethacin given intravenously nor the combination of these agents affected sodium chloride transport in this nephron segment.
Effects of Sulfhydryl Reagent, p-Chloromercuribenzoate, on p-Aminohippurate Transport by Isolated, Perfused Snake Renal Tubules
Authors: Dantzler William H. , Bentley Sherril K.
Published: November 2008

Effects of mercaptide-forming sulfhydryl reagent, p-chloromercuribenzoate (PCMB), on transport of p-aminohippurate (PAH) by isolated, perfused snake (Thamnophis species) renal tubules were studied. PCMB (10-7 mol/l) in bathing medium irreversibly inhibited net transepithelial transport of PAH (JPAH) without affecting net fluid absorption (Jv). PCMB (10-8 mol/l) in perfusate irreversibly inhibited JPAH without affecting Jv and markedly reduced the apparent permeability of the luminal membrane to PAH. These data suggest that sulfhydryl groups may be involved in the PAH transport steps at both the peritubular and luminal membranes.
Effects of Verapamil – a Calcium Inhibitor – on the Vasomotor Response of Cortical and Juxtamedullary Glomeruli of the Human Kidney
Authors: Martin-Dupont P. , Cambar J. , Brothier J.P.
Published: November 2008

Cortical and juxtamedullary glomeruli of the human kidney were isolated by sieving. Verapamil, a calcium inhibitor, was added to a suspension of the glomeruli. The vasomotor response was measured by a video analyser. We were thus able to determine the modiñcation of the cortical and juxtamedullary glomeruli surface area. Only the cortical glomeruli became vasodilated in response to the calcium inhibitor.
Glucocorticoid-induced Inhibition of the Reabsorption of Inorganic Phosphate in the Proximal Tubule in the Absence of Parathyroid Hormone
Authors: Durasin Ivan , Frick Anselm , Neuweg Mechtild
Published: November 2008

Previous studies from this laboratory have demonstrated a phosphaturic response to hydrocortisone. The present micropuncture studies were undertaken to localize this glucocorticoid-induced effect along the nephron. Adult female Sprague-Dawley rats were used and parathyroidectomized 3 h before the micropuncture. The animals were infused with modified Ringer solution (either without or with phosphate). Hydrocortisone increased both the end-proximal transtubular concentration gradient of inorganic phosphate, (TF/P)Pi, and the fractional delivery of Pi at the end of the proximal convolution significantly. The absolute reabsorption of Pi decreased from 95.1 ± 29.5 (mean ± SD) to 59.7 ± 28.2 pmol/min (p < 0.005) and the absolute reabsorption of Pi/single nephron glomerular filtration rate from 2.34 ± 0.59 to 1.35 ± 0.54 pmol/nl (p < 0.001) during Pi-Ringer infusion. It is concluded that the glucocorticoid-induced phosphaturia is primarily a result of the inhibition of the reabsorption of Pi in the proximal tubule.
Sex Difference of N-Acetyl-β-D-Glucosaminidase Activity in the Kidney, Urine, and Plasma of Mice
Authors: Funakawa Susumu , Itoh Takako , Miyata Kenji , Tochino Yoshihiro , Nakamura Masuhisa
Published: November 2008

N-Acetyl-β-D-glucosaminidase (NAG) activities in urine, kidney, and plasma were compared in an age-matched group of male and female ds mice. In males, the NAG activity in the kidney was significantly higher (p < 0.001), and the urinary NAG activity (unit/g creatinine) was 8-fold higher than those for females, while plasma NAG levels were significantly lower (p < 0.001). These findings indicate that when using urinary NAG activity to detect drug nephrotoxicity in mice, the different basal levels between males and females should be considered before drug administration.
Quantitative Morphological Studies of Aging Changes in the Kidney of the Lewis Rat
Authors: Bell, Jr. Richard H. , Börjesson Bengt A. , Wolf Paul L. , Fernandez-Cruz Laureano , Brimm John E. , Lee Sun , Sayers Hazel J. , Orloff Marshall J.
Published: November 2008

Spontaneous aging changes in the kidneys of the rat have been previously described. In the Lewis strain, we performed semiquantitative studies of kidney histology and quantitative studies of glomerular basement membrane thickness and mesangial area in animals aged 6–30 months. There is a progressive increase in glomerular basement membrane thickness and mesangial area throughout the life of the rat. Spontaneous glomerulosclerosis in the Lewis rat does not appear to be as extensive as in other strains. The importance of spontaneous glomerulosclerosis in studies of induced kidney disease is emphasized.
Hypocalciuric Effects of Hydrochlorothiazide in the Rat during NaHCO3, NaCl and NH4C1 Loading
Authors: Goulding Ailsa , Campbell Dianne
Published: November 2008

Hydrochlorothiazide (HCTZ) and NaHCO3 each lower urinary calcium excretion, while NaCl and NH4Cl each increase urinary calcium. This study examines the ability of HCTZ to lower urinary calcium during NaHCO3, NaCl and NH4Cl loading in the rat. We show that HCTZ lowers urinary calcium in rats treated with NaHCO3, NaCl and NH4Cl. We demonstrate that urinary calcium excretion is depressed to a greater degree by administering NaHCO3 and HCTZ in combination than by administering these agents separately.
Taurine Transport in Brush Border Membrane Vesicles Isolated from Hyper- and Normotaurinuric Mouse Kidney
Authors: Jean T. , Poujeol P. , Ripoche P.
Published: November 2008

The mouse strain C57BL is characterized by a high urinary fractional excretion of taurine. Hypertaurinuric [tau(-)] C57BL mice and three normal taurine ‘excretors’ [tau(+)] – Swiss, A/J, and C3H – were compared. Clearance experiments showed that fractional excretion of taurine was 4-8 times higher in C57BL relative to the other strains. Transport studies performed in brush border membrane vesicles, isolated from C57BL and C3H mouse renal cortex, showed that D-glucose uptake was similar in both strains while the taurine uptake appeared to be faster in tau(+) than in tau(-) mice. This difference was observed only in the presence of an inwardly directed NaCl gradient. The comparison of kinetic parameters showed a significant difference of apparent Km values: 90.8 ± 11.4 µM in tau(+) mice vs. 129.5 ± 17.1 µM in tau(-) mice. Jmax were not significantly different in both strains. These observations suggest a lower affinity of the taurine brush border membrane carrier in the hypertaurinuric strain as compared to the normotaurinuric mice. It is concluded that, in addition to a possible alteration of peritubular taurine efflux described by Rozen et al. (1983), a defect of taurine transport at the luminal membrane cannot be excluded and could account for the hypertaurinuria of the C57BL mice.
Quantitative Method for the Determination of Glycosaminoglycans from Small Quantities of Glomerular Basement Membranes
Authors: Parthasarathy Narayanan
Published: November 2008

A simple, sensitive, and efficient method is described for the quantitative determination of glycosaminoglycans from bovine renal glomerular basement membranes. After release from glomerular basement membrane by protease treatment, the glycosaminoglycans were isolated by a modified DEAE-cellulose column chromatographic procedure. Quantitation of glycosaminoglycans was achieved by hexuronate measurements with a microadaptation method employing m-hydroxydiphenyl. This procedure has proven useful in analyzing small samples of basement membranes as little as 0.75 mg. The glycosaminoglycan was identified as heparan sulfate by cellulose acetate electrophoresis and nitrous acid treatment.
Verapamil Effect on Renal Function of Normotensive and Hypertensive Rats
Authors: MacLaughlin M. , de Mello Aires M. , Malnic G.
Published: November 2008

The effect of verapamil, a Ca++ antagonist drug, on renal function and proximal fluid reabsorption in normal and hypertensive (GΠ) rats was studied. During intravenous infusion of verapamil, mean arterial pressure (MAP) fell significantly in both groups, 23% more in hypertensive than in normotensive rats. Glomerular filtration rate (GFR) was significantly higher in hypertensive rats and also increased significantly in this group during verapamil infusion. Effective renal plasma flow (ERPF) was similar in both groups and did not change significantly during verapamil infusion. The increase in urine flow, Na+ and Ca++ excretion was higher in hypertensive than in normotensive rats during verapamil infusion. When 10-5M verapamil was added to the luminal perfusate of proximal tubules, fluid reabsorption was reduced to 64% in normotensive and to 42% in hypertensive rats. When added to capillary perfusate, fluid reabsorption was almost completely but reversibly inhibited (92% in normotensive and 83% in hypertensive rats). Our findings indicate a direct effect of verapamil on renal Na+ and possibly also on Ca++ reabsorption, suggesting involvement of the Na+-Ca++ countertransport system. The greater effect of verapamil on Na+ excretion in hypertensive rats was not due to increased action on proximal Na+ reabsorption.
Species and Strain Differences in Urinary Protein Excretion
Authors: Alt J.M. , Maess B. , Hackbarth H.
Published: November 2008

The physiological excretion of urinary protein is subject to great variation influenced not only by environmental and hormonal factors but also by genetics. The present study demonstrates that there is not only variation in respect to the excretion of plasma proteins but also of other types of proteins which are specific urinary proteins. There is a close relation between body weight and total protein excretion. However, male rats and mice do not fit the allometric line calculated for the other species studied. This is of special importance since these two species are often used in kidney research. The reason for this divergence in total protein is the excretion of sex-dependent low molecular weight proteins. The excretion of albumin, which is a marker of glomerular permeability and tubular reabsorption as well, shows a marked genetic variation between different rat strains. The data presented in this study demonstrate the general admissibility of transferring data from one species to the other but also the limitations in respect especially to the sex-dependent proteins which are excreted by some species.
Impaired Sodium Excretion in Experimental Glomerulonephritis: an Explanation for the Controversies in the Literature
Authors: Chachati A. , Godon J.P.
Published: November 2008

Considerable discrepancies exist in the literature concerning Na excretion by the rat kidney in experimental antiglomerular basement membrane (GBM) glomerulonephritis (GN). Previous studies in our laboratories demonstrated a disturbance in Na excretion with an impaired absolute (UNa × V) and fractional (FENa) excretion of Na after saline loading. However, most of the other authors in the literature failed to observe similar findings. The present study was undertaken to elucidate some of these controversies: We showed that a difference in Na excretion between anesthetized GN and normal rats might not be detected after a volume expansion if the latter is small or slow (FENa in GN 2 ± 0.1%, in normals 2 ± 0.2%; not significant). Only a rapid and important volume expansion is sufficient to unmask such a difference between the two groups (FENa 3 ± 0.3 and 6 ± 1%, respectively, p < 0.001), and detect an impaired Na excretion in GN animals. The same amount of NaCl was nevertheless administered during slow and rapid volume expansion. Similarly, in GN conscious rats only after a saline load or repeated water loads did we observe a significantly smaller UNa × V compared to normals while no difference was present between the two groups after a single water load. In the literature, all the authors, that failed to demonstrate a disturbance in Na excretion in anti-GBM GN, administered slow and small isotonic saline loads to their rats. The hypothesis we formulate to explain these controversies is that the nonobserved disturbance in sodium excretion in most of these studies is probably secondary to insufficient natriuretic stimuli.
Renal Tubular Uptake of Protein: Effect of pH
Authors: Christensen Erik Ilsø , Bjerke Torbjørn
Published: November 2008

The present study was performed to determine to what extent pH influences protein reabsorption in renal proximal tubule cells. Rat surface proximal tubules were microinfused in vivo with 125I-labelled albumin in buffer solutions at different pHs. Tubular uptake was determined as the difference between microinfused and urinary trichloroacetic acid-precipitable radioactivity. In separate experiments the tubular uptake was followed by electron microscope autoradiography. The results showed that the uptake at pH 4.5 and 6.0 was about 15% higher as compared to uptake at pH 7.4. Furthermore, the electron microscope autoradiography demonstrated that albumin is taken up by endocytosis at acid pH as under normal conditions.
Antihypertensive and Bilateral Renal Responses to Nifedipine in 2-Kidney, 1-Clip, Goldblatt Hypertensive Rats
Authors: Huang Wann-Chu
Published: November 2008

Experiments were performed to assess the effects of nifedipine, a calcium channel blocker, on the blood pressure and bilateral renal function in 2-kidney, 1-clip, Goldblatt hypertensive rats. Hypertensive rats were prepared 4 weeks prior to the acute experiments. Nifedipine was administered intravenously into hypertensive (n = 11) and control (n = 12) rats under pentobarbital anesthesia. In hypertensive rats, nifedipine (0.02 mg/kg) reduced the mean arterial pressure from 151 ± 5 to 135 ± 5 mm Hg. Despite the fall of arterial pressure, there were significant increases in glomerular filtration rate (GFR) from 1.36 ± 0.13 to 1.80 ± 0.22 ml/min, urine flow from 7.8 ± 1.6 to 17.0 ± 3.8 µl/min, and excretions of absolute and fractional sodium from 1.07 ± 0.43 µEg/min and 0.50 ± 0.15% to 2.80 ± 0.73 µEq/min and 0.92 ± 17%, respectively, in the nonclipped kidney. No significant changes in these renal indices occurred in the clipped kidney. In control rats, administration of nifedipine (0.04 mg/kg) also significantly decreased the arterial pressure from 119 ± 4 to 110 ± 4 mm Hg. There were slight but insignificant increases in GFR and renal excretion of sodium and water. In both groups, nifedipine produced proportionate increases in osmolar clearance and free water reabsorption. These results suggest that nifedipine enhances glomerular filtration and suppresses the reabsoption of sodium and water by the proximal tubule and/or distal nephron segments. The resulting increase in excretory function of the nonclipped kidney may, in part, contribute to the blood pressure-lowering effect of this drug.
Sodium Chloride, Water and Urea Handling in the Rat Renal Medulla: A Computer Simulation
Authors: Barrett G.L. , Packer J.S. , Davis J.M.
Published: November 2008

A dynamic rat renal medullary model was employed to study how independent control of excretion of various substances is achieved. Salt and water reabsorptive coupling was heterogenous in the distal nephron. Diversion of filtrate to juxtamedullary nephrons retained salt with little effect on water or urea, a response enhanced by concomitant reduction in inner medullary blood flow. Urine concentration required high permeability and low flow in medullary blood vessels and active inner medullary salt transport. Collecting duct urea movement was closely coupled to that of water and urea recycling was enhanced by incorporation of nephrovascular bundles.
The Physiology of Renal Magnesium Handling
Authors: Quamme Gary A. , Dirks John H.
Published: November 2008

Present evidence suggests that the renal handling of magnesium is normally a filtration-reabsorption process as evidence for secretion is unsubstantiated. Magnesium reabsorption has distinctive features when compared with that of sodium and calcium. The proximal tubule concentration of magnesium rises to levels about 1.5 times greater than the glomerular filtrate and only 20–30% of the filtered magnesium is reabsorbed in this segment. Although the fractional reabsorption of magnesium is only half that of sodium, it changes in parallel with that of sodium in response to changes in extracellular fluid volume. The major portion of filtered magnesium (some 65%) is reabsorbed in the loop of Henle and evidence indicates that the thick ascending limb is the principal segment involved in magnesium absorption. Recent observations suggests that magnesium reabsorption in the ascending limb may be voltage dependent and secondary to active sodium chloride reabsorption. The loop of Henle appears to be the major nephron site where magnesium reabsorption is regulated possibly by cAMP-mediated hormones including parathyroid hormones, calcitonin, glucagon and antidiuretic hormone. About 10% of the filtered magnesium is delivered into the distal nephron. The distal tubule reabsorbs only a small fraction of the filtered magnesium which may be regulated by the same cAMP-mediated hormones involved in control of magnesium in the loop.
Effect of Carbonic Anhydrase Inhibition on (U-B)pCO2 in the Alkaline Urine of the Rabbit
Authors: Kekomäki Martti , Maren Thomas H. , Wingo Charles S.
Published: November 2008

We studied factors influencing urine pCO2minus blood pCO2 [(U-B)pCO2] in rabbits infused with sodium bicarbonate solutions. Unlike other species, the rabbit does not develop a significant (U-B)pCO2 (urine pCO2 > blood pCO2) after alkali or acid buffer infusion. However, intravenous acetazolamide immediately induced a significant (U-B)pCO2· The effect could not be related to the blood pH or pCO2 the urinary concentration of bicarbonate or inorganic phosphate, or to changes in plasma potassium concentration. Methazolamide was also effective in increasing (U-B)pCO2- This significant (U-B)pCO2 was present after carbonic anhydrase inhibition in rabbits subjected to chronic partial obstruction of urinary flow and in rabbits treated with 11-desoxycorticosterone acetate (DOCA). We propose that carbon dioxide is normally dissipated from the alkaline urine of the rabbit by a distal tubular mechanism, which involves catalytic conversion of carbon dioxide to bicarbonate. Inhibition of carbonic anhydrase leads to the formation of a significant (U-B)pCO2· In the rabbit, pCO2 may be an index of collecting duct acidification under certain circumstances; however, the relation of collecting duct acidification to the high (U-B)pCO2 during the inhibition of carbonic anhydrase remains to be determined.
Aminoglycoside and Nephrotoxicity
Authors: Costa Silva V.L. , Gil Zaladek , Nascimento G. , Cavanal M.F.
Published: November 2008

The effect of three aminoglycosides – gentamicin, netilmicin and amikacin – on renal acid excretion was studied in male rats treated with doses equivalent to those clinically used. The amikacin and netilmicin groups showed no important changes in the values of glomerular filtration rate (GFR), effective renal plasma flow (ERPF) and U/P inulin ratio during normal and acidotic conditions. The gentamicin group, however, showed a clear tendency to decreases in these functional parameters even in normal conditions, a finding that reinforces the concept that gentamicin is more nephrotoxic than other aminoglycosides. During normal conditions net acid excretion (BH) did not change with any of the three tested drugs. However, after an acute acid load BH markedly fell regardless of the antibiotic used. The capacity to elevate the urine-blood pCO2 was preserved after an alcaline overload, suggesting that the distal tubule was not significantly affected by aminoglycoside treatment. These data suggest that the clinical use of aminoglycosides during metabolic acidosis deserves close attention due to the possible deleterious effect that can emerge as the result of an inappropriate retention of acid loads.
Ecto-5’-Nucleotidase of Cultured Rat Mesangial Cells
Authors: Stefanovic Vladisav , Savic Vojin , Vlahovic Predrag , Ardaillou Nicole , Ardaillou Raymond
Published: November 2008

Because adenosine plays a role in the regulation of glomerular filtration rate and of the release of renin, we examined the possibility of a local source for this mediator. We found that rat cultured glomerular mesangial cells converted 5’-AMP into adenosine. The properties of the enzyme involved in the reaction were those of an ecto-5’nucleotidase: (1) the products of the reaction were generated in the extracellular fluid although no 5’-nucleotidase was released by the cells into the medium; (2) identical activities were found for cultured cells in situ and sonicated cells; (3) the diazonium salt of sulfanilic acid which is a nonpenetrating reagent inhibited up to 75% of the enzyme activity. Ecto-5’-nucleotidase activity of intact cells obeyed Michaelis-Menten kinetics. Apparent Km for 5’-AMP was 0.32 mM. 5’-UMP was a strictly competitive inhibitor. ADP exerted a very powerful inhibitory effect and behaved also as a competitive inhibitor. ATP was inhibitory both by increasing Km and by decreasing Vmax. Ecto-5’-nucleotidase was active in the absence of divalent cations. However, Mg2+, Ca2+, Co2+ and Mn2+ were stimulatory. Zn2+ and Cu2+ suppressed the activity. Concanavalin A, a plant lectin, was markedly inhibitory, suggesting that a glycoprotein moiety was necessary to express enzyme activity. Ecto-5’-nucleotidase activity was not modified during phagocytosis of serum-treated zymosan by mesangial cells. Rat cultured glomerular epithelial cells exhibited a 5’-nucleotidase activity which was 4 times lower than that of the mesangial cells in primary culture. Activity was also present in freshly isolated glomeruli and total cortex, but at lower concentrations than in mesangial cells. These findings suggest that ecto-5’-nucleotidase of mesangial cells may be the main source of adenosine within the glomeruli. Therefore, activity of this enzyme should be essential in the regulation of the glomerular microcirculation.