bluuebunny/crossref_metadata_2025 huggingface dataset:
Postpartum Resolution of Glomerular Changes in Edema-Proteinuria-Hypertension Gestosis
Authors: Oe P.L. , Ooms E.C.M. , Uttendorfsky O.T. , Stolte L.A.M. , van Delden L. , Graaff P.
Published: November 2008

Complete resolution of glomerular changes in toxemia of pregnancy has been reported to occur as early as 4 weeks postpartum, whereas their persistence for as long as 2 years in some instances has been noted. However, the mechanism of resolution remains obscure. Percutaneous renal biopsy was performed in 22 patients between 10 and 14 days after delivery. These women fulfilled the criteria for toxemia of pregnancy (edema-protein -uria-hypertension gestosis). Biopsy specimens were examined, using light, immunofiuorescence and electron microscopy. Semithin sections were studied in view of greater reliability and better relation with further electron microscopic studies. A diffuse increase in mesangial cellularity and matrix was seen in all glomeruli with varying intensity, compatible with mesangium activity, more than endothelial proliferation. So-called capillary occlusions by endothelial swelling were not observed in the biopsies taken 10 days after delivery, but expulsed mesangial cytoplasm could be observed incidentally in the capillary lumen. This phenomenon may explain the wrong interpretation of paraffin sections studied by light microscopy. The presence of immunoglobulins in the glomeruli, seen by immunofluorescence, seems to be nonspecific trapping. In view of experimental studies of mesangium function in macromolecular uptake and processing, it is possible that resolution of the characteristic renal lesions in toxemia is promoted by mesangium activity.
The Dense Deposits Disease of the Renal Basement Membranes
Authors: Droz D. , Noel L.H. , Nabarra B. , Leibowitch J.
Published: November 2008

Dense-deposits disease is characterized by an original morphological aspect of the renal basement membranes which have an electron-dense appearance. The immunofluorescence studies showed C3 alone in kidney. Low serum C3 levels and the presence of C3 NF activity have been detected in this disease, demonstrating an activation of the complement alternative pathway. The observation of recurrence in transplanted kidneys contributed to establish the sequence of the morphological events and showed the dissociation between the serological complement profiles and the lesions. Although the nature of the dense deposits remains still unknown, the altered membranes are recognized by at least some anti-GBM antibodies.
Biochemical Properties of Glomerular Basement Membrane in Daunomycin Nephrosis and Nephrotoxic Serum Nephritis
Authors: Koide Hikaru , Soeda Noboru , Ohno Joji
Published: November 2008

Glomerular basement membrane (GBM) were isolated from the kidneys of rats suffering from daunomycin nephrosis or nephrotoxic serum nephritis. The GBM from daunomycin nephrotic rats contained significantly less hydroxyproline, hydroxylysme and glycine than that of control rats. There was an increase in glucosamine content in the membrane. No significant change was found in the neutral sugar content. In nephrotoxic serum nephritis, the relative amounts of hydroxyproline, glycine and half-cystine were decreased, whereas the relative amounts of aspartic acid, alanine, lysine and hydroxylysine were increased. The ratio of hydroxyproline to proline and the ratio of hydroxylysine to lysine were decreased. An increase in sialic acid content and a decrease in fucose and hexosamine content and glucosyl-galactosyl-hydroxylysine content were noted in nephrotoxic nephritic GBM. These chemical structural alterations could account for the functional disorders of diseased GBM.
Inhibition of Increased Synthesis of Glomerular Basement Membrane Collagen in Diabetic Rats in vivo
Authors: Hasslacher C. , Bürklin E. , Kopischke H.G.
Published: November 2008

Diabetic rats were treated intraperitoneally for 2 weeks with (+)-catechιn in two different dosages or calcium dobesilate and the influence of these substances on protein and basement membrane collagen synthesis was investigated. Both drugs did not alter the diabetic metabolic situation. At the lower dose, (+)-catechin led to a slight decrease and at the higher dose to a small increase of basement membrane collagen synthesis. But compared to untreated controls these differences were statistically not significant. Calcium dobesilate inhibited markedly the raised basement membrane collagen synthesis. However, this effect does not appear to be specific, since the raised general protein synthesis was also reduced. These findings show that the disturbed basement membrane metabolism in diabetes can be influenced without altering the metabolic situation.
Circadian Rhythms of Plasma Renin Levels in the Anesthetized Rat
Authors: Rodríguez-Sargent Carmen , Cangiano José L. , Martínez-Maldonado Manuel
Published: November 2008

Circadian rhythms of plasma renin activity (PRA) is described in the ether anesthetized rat. PRA values are significantly higher than corresponding values previously reported in the awake rat. Peak activity was observed at 12.00 and 16.00h, similar to the pattern of diurnal rhythm established in the conscious rat. The reproducibility of PRA in the anesthetized rat is demonstrated by relatively constant values obtained from a separate group of rats bled at the same hour every other week. In addition, each sample was also incubated with excess renin substrate for the determination of relative plasma renin concentration (PRC). The pattern obtained for PRC is similar to that of PRA, indicating that the circadian rhythms result from variations of plasma renin rather than changes in renin substrate. Furthermore, although ether anesthesia raises the basal levels of PRA, it does not interfere with the demonstration of the normal pattern of circadian rhythms.
Interdependence of O2 Consumption, Renal NEFA Pattern and N-Acetylation of PAH in the Isolated Perfused Rat Kidney
Authors: Mályusz M. , Ehrens J. , Uschtrin D.
Published: November 2008

Tissue concentration of nonesterified fatty acids (NEFA) exerting an inhibitory effect on renal N-acetyltransferase activity was determined in the isolated perfused rat kidney. Concurrently, O2 consumption and the N-acetylation rate of p-aminohippurate (PAH) were measured. In a second series of experiments, the mode of inhibition of NEFA on acetylating enzyme(s) was studied. Amount and pattern of NEFA as well as N-acetylation rate of PAH in the kidney were related to the O2 consumption: lower O2 supply corresponded to a higher tissue NEFA concentration as well as lower N-acetylation rate, increased O2 supply resulted in a low tissue NEFA concentration and an increased N-acetylation rate of PAH. Decreasing O2 supply elevated the tissue concentration of linoleate especially. NEFA with a carbon chain length of C16-C20 inhibited renal N-acetyltransferase activity in vitro competitively according to the sequence C16, C18, C18:1, C18:2, C18:3=C20. It is inferred that hypoxia interferes with the N-acetylation of PAH in the rat kidney by increasing the content and changing the pattern of fatty acids, thereby inhibiting the N-acetylating enzyme(s).
Urinary and Systemic Metabolites of Prostacyclin in the Perfused Rabbit Kidney
Authors: Rosenkranz B. , Hofbauer K. , Fischer C. , Frölich J.C.
Published: November 2008

Rabbit kidneys were isolated and perfused with a solution to which tritiated or unlabeled prostacyclin was added continuously. The ureteral and venous effluents were collected separately and chromatographed. The peaks obtained by high-pressure liquid chromatography were analyzed using gas chromatography-mass spectrometry. The characteristic fragments of dinor-6-keto-PGF1α could be detected from ureteral and venous effluents and represented material corresponding to 9.6 and 9.1% of the radioactivity recovered from chromatography, respectively. In addition, 39.2% (ureteral effluent) and 58.2% (renal venous effluent) of the radioactivity could be identified as 6-keto-PGF1α, the stable in vitro hydrolysis product of prostacyclin. These results show that the kidney is able to degrade prostacyclin by β-oxidation and that dinor-6-keto-PGF1α formed in the kidney can be detected in both the vascular and urinary compartments.
Differences in Effects of Amino-Terminal and Intact Parathyroid Hormone on Calcium, Phosphate, and cAMP Excretion by the Isolated Perfused Rat Kidney
Authors: Besarab Anatole , Swanson John W.
Published: November 2008

Urinary cAMP (UcAMP) reflects activation of renal adenylate cyclase by parathyroid hormone (PTH). UcAMP excretion and the phosphaturic, anticalciuretic responses to bovine PTH by a stable isolated perfused rat kidney were compared. Dose-response curves were obtained for two synthetic amino-terminal [1–34] PTH preparations and three highly purified intact [1–84] PTH preparations. With all preparations, anticalciuria occurred at lower concentrations ( < 10-10 M) than those needed to produce a significant increase in UcAMP excretion or phosphate excretion. Maximal decreases in calcium clearance with [1–34] PTH were independent of concentrations between 10-10 and 10-7 M whereas cAMP and phosphate increased sigmoidally at PTH concentrations above 10-10 M. The two synthetic [1–34] PTH preparations had identical anticalciuretic and phosphaturic dose-response curves despite their significantly different effects on cAMP excretion. Intact [1–84] PTH concentration-response curves were identical to those of [1–34] PTH at concentrations less than 3×10-9 M. At higher concentrations, phosphaturia was greater and anticalciuria blunted compared to [1–34] PTH. These latter changes were associated with natriuresis and kaliuresis, effects not seen with [1–34] PTH. The isolated kidney may be a useful model for further studies of PTH action and also constitutes a bioassay system to evaluate hormone potency.
The Renin Angiotensin System in Conscious Brattleboro Strain Rats
Authors: Kinter Lewis B. , Shier David , Flamenbaum Walter , Beeuwkes, III Reinier
Published: November 2008

Plasma renin activity (PRA) was measured in conscious Brattleboro strain, vasopressin (AVP)-defícient diabetes insipidus (DI) and heterozygous rats with the aid of chronically implanted catheters. Baseline, dehydration-stimulated, and hemorrhage-stimulated levels of PRA were elevated in DI rats, as compared to levels in heterozygous controls. Replacement therapy with either AVP or the nonpressor AVP analog dDAVP reduced PRA to control levels. The high level of PRA in DI rats was associated with the lack of endogenous antidiuretic activity per se and not the pressor activity associated with the vasopressin molecule. Thus, elevated PRA in the chronic absence of AVP (in DI rats) most probably results indirectly from the chronically reduced plasma volume reported associated with hypothalamic diabetes insipidus.
Localization by Immunofluorescent Microscopy of Several Collagen Types and of a Basement Membrane Proteoglycan in Rat Glomerular Epithelial and Mesangial Cell Cultures
Authors: Foidart J.B. , Foidart J.M. , Hassell J. , Mahieu P.
Published: November 2008

Confluent cultures of rat glomerular epithelial and mesangial cells were studied by immunofluorescent microscopy, using affinity-purified antibodies directed against collagen of type I-V or an antiserum directed against a basement membrane (BM) proteoglycan. The epithelial cells were stained by antibodies directed against type I, IV and V collagen, whereas the mesangial cells were stained by all the antibodies directed against the different collagenous antigens tested. Therefore, only mesangial cells contained antigenic determinants of type III collagen. On the contrary, both cell types possessed BM proteoglycan antigens. The data suggest that rat glomerular epithelial and mesangial cells may be implicated in the biosynthesis of different components of normal (and pathological) glomerular BM.
The Susceptibility of the Mesangial Matrix of Isolated Cell-Free Glomeruli to Limited Proteolysis
Authors: Krakower Cecil A.
Published: November 2008

Selective lysis of mesangial matrix can be achieved by limited proteolysis of isolated cell-free glomeruli. Such treated glomeruli present unfolded and confluent capillary loops forming irregularly shaped, saccular lobular structures, comparable to those described for chemical mesangiolysis. It was observed that the parietal capsules of the glomeruli were also susceptible to limited proteolysis by comparison with the resistance of the basement membranes of the peripheral capillary loops.
Failure of Atrial Myocardial Extract to Inhibit Renal Na+, K+-ATPase
Authors: Pollock David M. , Mullins Margaret M. , Banks Robert O.
Published: November 2008

The effects of a natriuretic factor contained in extracts of the atrial myocardium on an isolated renal Na+, K+-ATPase enzyme system were evaluated. Ultrafiltrates (molecular weight < 30,000) of boiled extract of rat atria and ventricles were prepared. Infusion of 100 µl of the atrial ultrafiltrate into bioassay rats resulted in a prompt, short-lived natriuresis and diuresis. However, addition of 100 µl of the atrial ultrafiltrate to 900 µl of a suspension containing Na+, K+-ATPase had no significant effect on enzymatic activity. Similarly, ultrafiltrates of ventricular extract also had no significant effect on Na+, K+-ATPase activity. These results indicate that the atrial natriuretic factor does not alter renal tubular sodium reabsorption by directly inhibiting the Na+, K+-ATPase enzyme system.
Glomerulotubular Balance and Prostaglandin Synthesis
Authors: Langberg Harold , Hartmann Anders , Vikse Arild , Kiil Fredrik
Published: November 2008

We have tested a hypothesis proposed to explain glomerulotubular balance (GTB) as a consequence of variations in prostaglandin synthesis. Arachidonic acid (40 µg • kg-1 • min-1) infused into the renal artery of anesthetized dogs raised renal blood flow (RBF) by 41 + 5% in hydropenic and by 24 + 11% in volume-expanded dogs, but the absolute changes were similar. The infusion of arachidonic acid after the administration of indomethacin (10 mg·kg-1) had no effect on RBF. Arachidonic acid infusion increased the excretion of sodium and chloride in hydropenic dogs but not after the administration of ethacrynic acid in volume-expanded dogs. During continued infusion of ethacrynic acid, the glomerular filtration rate (GFR) was lowered by suprarenal aortic constriction and raised by carotid constriction. A linear relationship between electrolyte reabsorption and GFR (GTB) was observed when GFR was varied between 20 and 110% of control. GTB and tubular reabsorption at comparable GFR were not significantly altered during arachidonic acid infusion or after indomethacin administration. In all experimental settings, bicarbonate, chloride, and sodium reabsorption were altered in molar ratios of 1:2:3 during variations in GFR. We conclude that GTB is independent of variations in prostaglandin synthesis.
In vitro Correlation of Glutamine and Glutamate Renal Ammoniagenesis during Adaptation
Authors: Preuss Harry G. , Gaydos DiAnna Slemmer , Aujla Manjeet Singh , Areas Jorge , Vertuno Leonard L.
Published: November 2008

Renal slices from 191 rats in various states of acid-base balance were investigated for their ability to produce ammonia from both glutamine and glutamate. Under a variety of conditions, in three different type studies, a significantly similar correlation existed between ammonia adaptation from glutamine and glutamate. This relationship was maintained during acute and chronic acidosis and during alkalotic inhibition of renal ammoniagenesis. We conclude from our findings that ammonia adaptation in rats secondary to acute and chronic acidosis is similar, although incomplete during acute acidosis. Our results further support the hypothesis that the rate of glutamate deamination is a major mechanism for overall renal ammonia adaptation in rats during acid-base changes.
Effects of Volume Expansion with Fluosol-DA on Renal Function of the Nonhuman Primate
Authors: Roccaforte William H. , Wesley Charles R. , Gilmore Joseph P.
Published: November 2008

The renal responses to an intravenous infusion of a high O2 affinity fluorocarbon equal to 15% of the estimated blood volume was determined in 5 monkeys and 1 baboon. In response to the infusion, blood pressure, renal plasma flow and glomerular filtration rate did not change significantly while heart rate and central venous pressure increased transiently. Significant increases in sodium and potassium excretion and osmolal and free-water clearances occurred. The renal responses to Fluosol-DA (20%) mimic in general those observed when blood volume is expanded with isotonic isooncotic dextran solutions.
Effects of Verapamil and Nifedipine on Renal Function and Hemodynamics in the Dog
Authors: Bell Anthony J. , Lindner Armando
Published: November 2008

This study evaluates the direct effects of verapamil (5 µg/kg/min) or nifedipine (0.32 µg/kg/min) when infused into one renal artery for 2 h. The role of calcium in the systemic and renal vascular effects of angiotensin II (1 µg/i.v.bolus) was examined in each period.Renal blood flow was increased 11% by verapamil and 29% by nifedipine. Unlike other vasodilators, these drugs markedly increased GFR (by 75% with verapamil and 50% with nifedipine), and both caused a profound natriuresis, which outlasted the renal hemodynamic changes. Further, they abolished the renal vascular responses to angiotensin II. These major direct effects on renal function and hemodynamics suggest that: (a) calcium blockers may affect the determinants of GFR differently from other vasodilators, and (b) they may interfere with proximal tubular Na+ transport.
Further Characterization of the Endogenous Natriuretic and Digoxin-Like Immunoreacting Activities in Human Urine: Effects of Changes in Sodium Intake
Authors: Kramer Herbert J. , Heppe Marita , Weiler Elmar , Bäcker Angela , Liddiard Colin , Klingmüller Dietrich
Published: November 2008

In the present study natriuretic activity and digoxin-like immunoreacting activity (DLIA) were determined in small molecular weight (MW) fractions of urine from healthy subjects during low (35 mmol/day) and high ( > 400 mmol/day) sodium intake by bioassay and by a radioimmunoassay for digoxin, respectively. After gel filtration of urine on a Sephadex®G-25 column the natriuretic activity appeared in the post-salt fraction SIV, whereas DLIA was present in small amounts in the salt fraction SIII and, with consistently higher activity, in the post-salt fraction SIV. Natriuretic activity significantly increased and DLIA decreased in fraction SIV with high sodium intake, but total urinary excretion of DLIA remained unaltered during changes in sodium intake. In addition, anion-exchange and reverse-phase chromatography revealed that DLIA is not specifically related to the natriuretic activity but also reflects unspecific binding of various urine constituents to this digoxin antibody. Although the antibody binds a natriuretic material, this radioimmunoassay is thus unsuitable to determine the endogenous natriuretic activity in urine fractions. Whereas they elute differently on reverse-phase chromatography, amino acid analyses revealed that both the natriuretic factor directly purified from the post-salt fraction SIV and the natriuretic material bound to the digoxin antibody have in common four amino acids at similar molar ratios. The physicochemical properties as evidenced by chromatographic and electrophoretic studies as well as enzymatic inactivation suggest that the low MW natriuretic factor(s) in human urine may be associated with a small peptide(s) of weak acidic nature.
An Attempt to Measure Glomerular Plasma Flow by the Cationic Dyes Alcian Blue and Ruthenium Red
Authors: Lavik O.J. , Aukland K.
Published: November 2008

Autoradiography showed that 3H-labelled alcian blue injected into the rat renal artery was concentrated in the glomeruli. To test if the uptake could be used as a measure of local glomerular plasma flow, the one-pass extraction was measured in 19 rats. The average extraction was 31.9% (SD 8.0%). Impurities and heterogeneity of the tracer as well as reversible binding to erythrocytes may have contributed to the low estimated extraction. The average extraction of 103Ru-ruthenium red was 26.3%. We conclude that neither of these dyes are suitable for measurement of glomerular plasma flow.
Comparative Aspects of Glomerular Filtration in Vertebrates
Authors: Yokota Stanley D. , Benyajati Siribhinya , Dantzler William H.
Published: November 2008

Glomerular ultrafiltration of the plasma is a fundamental component of vertebrate renal function. The importance of the glomerulus is reflected by its near-universal presence and great elaboration among the vertebrates. Although the general structural features and functional properties of the glomerulus appear to be largely similar among diverse groups, there exists considerable variation in the magnitude of the rate of filtration. The kidney is the primary vertebrate organ responsible for water and metabolic waste excretion, and glomerular filtration plays an important role in these functions. Therefore, the magnitude of the GFR appears to be influenced primarily by the rates of water influx and metabolism. Major phylogenetic differences in morphological, physiological and metabolic design have a decisive impact on the magnitude of the GFR. The endothermic classes, with more numerous glomeruli, high metabolic rates, and high ultrafiltration pressures, have proportionately higher rates of glomerular filtration than the ectothermic groups. As a group, the reptiles, with presumably the lowest rates of water influx, exhibit the lowest GFRs. Within each class, there are trends toward species with greater access to free water having higher GFRs (e.g. fresh water vs. marine; mesic vs. xeric. The clearest examples exist for the teleosts, with marine forms having lower GFRs than their fresh water relatives. The coupling of the GFR to environmental influences is also demonstrated by the response of the animal to environmentally imposed perturbations, such as dehydration. In terrestrial animals during dehydration, reductions in the rate of glomerular filtration occur reducing the rate of urinary water loss. And increases in GFR appears to be important in the rapid elimination of water loads in nonmammalian vertebrates. This short-term modulation of the GFR occurs by either changing glomerular plasma flow or glomerular capillary hydrostatic pressure, or both. In addition, shifts in the filtering populations of glomeruli can take place, as has been demonstrated in birds. Although the mediators of these effects have not been unequivocally identified, several hormones, including antidiuretic hormone, angio-tensin, and catecholamines, have been implicated.
Comparative Aspects of the Urinary Concentrating Process
Authors: Braun Eldon J.
Published: November 2008

Only birds and mammals can produce urines that have higher osmolalities than their plasma. In both of these vertebrate groups this is accomplished through the operation of a countercurrent multiplier system although the details of the system may differ somewhat between the two groups. In most mammals the loop of Henle has a thin ascending limb of variable length. In birds, the loop of Henle does not have a thin ascending portion as the tubule epithelium always thickens before the hairpin turn. In mammals, both urea and sodium chloride contribute to the medullary interstitial osmotic gradient although the exact contribution of each osmolyte can vary in time and from species to species. In birds the interstitial osmotic gradient is made up almost entirely of sodium chloride. The development of the avian renal medulla (medullary cone) is very similar to the outer medulla of mammals.
Renal High-Molecular-Weight Renin: Unusual Formation in the Aged Stroke-Prone Spontaneously Hypertensive Rats
Authors: Itoh Satoko , Tanaka Motoharu , Ikemoto Fumihiko , Yamamoto Kenjiro , Morita Nobuko , Okamoto Kozo
Published: November 2008

A high-molecular-weight renin (HMWR) was detected in the plasma (molecular weight 50,600) and renal cortical homogenate (molecular weight 57,000) of 25-week-old male stroke-prone spontaneously hypertensive rats (SHRSP), in contrast to the renin with a molecular weight of 38,000 in normotensive Wistar Kyoto rats (WKY) and 5-week-old SHRSP. However, renin granules contained only the renin with a molecular weight of 38,000, indicating that the renal HMWR is not a native form but is probably a renin/renin-binding protein complex. Such HMWR was not produced when the renal cortex was homogenized with an equal amount of renal cortex of WKY. Further, the HMWR of the aged SHRSP was converted into the 38,000-dalton renin, when incubated with the extract of renal cortex of WKY. Thus, the existence of a renal cortical substance that converts the renal HMWR into the 38,000-dalton renin was evidenced. This substance was fractionated with DEAE-cellulose and was characterized as a putative SH enzyme. We conclude that a deficiency in the HMWR-converting substance may be attributed to the unusual formation of HMWR in the aged SHRSP.
Renin Granules Isolated from Rat Kidney Cortex by Continuous Colloidal Silica (Percoll) Density Gradient Centrifugation
Authors: Matsumura Yasuo , Takeshita Michiyo , Miyawaki Nobuaki , Iwamoto Takahiro , Morimoto Shiro
Published: November 2008

Renin granules were isolated from rat kidney cortex by a continuous polyvinyl-pyrrolidone-coated colloidal silica (Percoll) density gradient centrifugation. A major peak of renin activity was found at a density of 1.12–1.13 g/ml, and the specific activity of renin in the peak fraction was increased by approximately 70-fold, as compared with that in the kidney cortex homogenate. On the other hand, activities of other reference enzymes, such as succinate dehydrogenase, acid phosphatase and glucose-6-phosphatase, were not detectable in the peak fraction. When the extract of the peak fraction was applied to a pepstatin column, trypsin-activated renin could not be detected in the breakthrough fractions. These results indicate that renin granules of the rat kidney cortex contain only active renin.
Renin Status of the Afferent Arteriole and Ultrastructure of the Juxtaglomerular Apparatus in ‘Superficial’ Juxtamedullary Nephrons from Rats
Authors: Casellas Daniel , Taugner Roland
Published: November 2008

The present light (LM) and transmission electron microscopic (TEM) studies were carried out to further document the anatomy of the ‘superficial’juxtamedullary nephrons (SJMNs) located on the inside cortical surface of the rat kidney. TEM revealed that SJMNs possess all vascular and tubular cell types constituting the juxtaglomerular apparatus (JGA) in typical cortical and juxtamedullary nephrons (JMNs). Proximal to the glomeruli, epithelioid cells filled with secretory granules predominated in the media of afferent arterioles. The presence of renin in the granules was immunocytochemically demonstrated by the protein A-gold method. Further upstream from the glomeruli, epithelioid cells alternated with plain smooth muscle cells. The use of renin and angiotensin II antisera revealed similar arteriolar distributions of renin and angiotensin II positive cells in SJMNs as well as in typical JMNs. Numerous nerve terminals were found along afferent and efferent arterioles, suggesting a dense innervation of these vessels. The distribution of renin-containing (i.e., epithelioid) cells in the preglomerular arterioles was assessed in various nephron populations by LM using the PAP method and renin antiserum. In SJMNs, most renin-positive cells were found in the vicinity of the JGA along a mean arteriolar length of 35 ± 3 µm (range 7–107 µm). In JMNs, renin-positive cells had a similar distribution along a mean arteriolar length of 35 ± 1 µm. Scattered renin-positive cells were observed up to a maximal arteriolar length of 173 and 238 µm in SJMNs and JMNs, respectively. In conclusion, the present TEM and LM studies demonstrate that in spite of their unique cortical localization SJMNs cannot be distinguished from typical JMNs with respect to JGA ultrastructure and the renin-angiotensin status of their afferent arterioles.
Renal Effects of Angiotensin II: Role of Prostaglandins?
Authors: Shohat J. , Erman A. , Boner G. , Rosenfeld J.B.
Published: November 2008

In the present study the possible role of endogenous prostaglandins in modulating the renal effects of angiotensin II was investigated in the isolated perfused rat kidney. Angiotensin II (5 ng/ml) caused both an increase in prostaglandin E2 synthesis and an increase in renal vasular resistance, as well as an increase in perfusate flow rate and glomerular filtration rate. Filtration fraction did not change. Inhibition of prostaglandin synthesis did not influence these effects of angiotensin II. In addition, angiotensin II caused natriuresis and to a lesser degree kaliuresis. These effects were independent of intrarenal hemodynamic effects. Inhibition of renal prostaglandin synthesis did not have any effect on the angiotensin-induced natriuresis. We conclude that the natriuretic effect of angiotensin II is independent of renal prostaglandin synthesis.
Unilateral Renal Arterial Infusion and Renal Vein Catheterization in Rabbits
Authors: Cho Kyung Woo , Koh Gou Young , Kim Suhn Hee , Seul Kyung Hwan
Published: November 2008

This study evaluates the direct effects of verapamil and furosemide infused into the unilateral renal artery on renal function and the renin secretion rate in renal vein-catheterized rabbits. Catheterization did not alter the renal function parameters of the kidney. Verapamil and furosemide increased renal blood flow, urine flow, and urinary sodium, potassium and chloride excretions confined to the infused kidney. Verapamil increased the glomerular filtration rate and free water clearance. The renin secretion rate was increased by furosemide but not by verapamil. The present study shows that the technique is applicable to renal function studies in which unilateral renal arterial infusion of the agents studied is required. The contralateral kidney can be a reliable control for the infused kidney. It also provides a useful technique for the study of renin release in rabbits.
Effects of Administered Thromboxanes on the Intact, Normal Rat Kidney
Authors: Baylis Christine
Published: November 2008

The effects of administered thromboxanes on the intact, normal rat kidney were studied. Euvolemic male rats received intraarterial infusions of thromboxane B2 (TXB2) and the stable thromboxane A2 analog (U46619) and the effects on renal function were investigated, using glomerular micropuncture and whole-kidney clearance techniques. Both TXB2 and U46619 were renal vasoconstrictors and lowered GFR by reducing renal plasma flow rate; U46619 was much more potent that TXB2. Neither agent caused any marked change in the glomerular capillary ultrafiltration coefficient (Kf). Thus in the rat, the thromboxanes reduce filtration rate by increasing renal vascular resistance and without exerting a marked influence on Kf.
A Method for Studying the Effect of Vasoactive Substances on Glomerular Filtration Without Affecting the Central Haemodynamics
Authors: Källskog Örjan , Wolgast Mats
Published: November 2008

A method for mirocatheterization of rat kidneys was developed. The catheter consists of 50–100 µm thick polyethylene tubes, and is inserted into the interlobular or arcuate arteries via a lumbar artery. The technique makes it possible to perfuse a small number of nephrons with very high doses of vaso active substances without affecting the nephrons in the vicinity or the central haemodynamics. By adding labelled inulin to the perfusate it is also possible to calculate the amount of drug reaching the nephron under study. It was shown that the catheterization and perfusion with Ringer solution per se have no effect on the nephron function. Perfusion with very high doses of acetylcholine was found to have a selective effect on the area perfused but caused no changes in central haemodynamics, or on nephrons in unperfused areas. It is concluded that the technique is suitable for use in studies concerning the handling of high doses of vasoactive substances by the nephron.
Osmotic Diuresis
Authors: Lang Florian
Published: November 2008

Osmotic diuresis occurs, if nonreabsorbed solutes such as mannitol impair the reabsorption of water. The reduced reabsorption of volume affects in turn the reabsorption and excretion of solutes. Thus, mannitol leads to modest impairment of proximal tubular reabsorption not only of water, but as well of electrolytes (Na, Cl, K, Pi, Ca, but not Mg), urea, and uric acid. Infusion of hypertonic mannitol increases renal blood flow and the glomerular filtration rate of superficial nephrons. The increased perfusion of medulla leads to wash out of medullary hypertonicity. The decline of medullary osmolarity leads to a marked impairment of water reabsorption in descending limbs and possibly to moderate impairment of NaCl, Ca, and Mg reabsorption in the ascending limbs of Henle’s loop. In the collecting duct, inhibition is marked of water and urea reabsorption and modest of NaCl reabsorption. A number of open questions remain, such as the mechanisms underlying decrease of renal vascular resistance, increased proximal tubular reabsorption of magnesium, or impaired NaCl reabsorption in thick ascending limbs.
Potassium-Sparing Diuretics
Authors: Horisberger Jean-Daniel , Giebisch Gerhard
Published: November 2008

Amiloride, triamterene, and the spirolactones are potassium-sparing diuretics which act on the distal parts of the nephron, from the late distal tubule to the collecting duct. In these segments, active sodium reabsorption occurs through the following mechanism: sodium ions enter the cell through specific channels present in the luminal membrane and are extruded out of the cell into the peritubular medium by a sodium-potassium exchange pump, the Na-K-ATPase. Amiloride in micromolar concentrations reduces the sodium transport by blocking the luminal membrane sodium channel. Triamterene has a similar effect, although with a lower affinity; the available studies do not allow to determine if an inhibitory effect of triamterene on the Na-K-ATPase plays an additional role in its diuretic action. The spirolactones are competitive inhibitors of aldosterone, the mineralocorticoid hormone which
Renal and Renin Effects of Sodium Thiopental in Rabbits
Authors: Cho Kyung Woo , Kim Suhn Hee , Koh Gou Young , Seul Kyung Hwan , Kim Hae Ja , Song He Sun
Published: November 2008

Unilateral renal arterial infusion of sodium thiopental on renal function and renin secretion were investigated in unanesthetized rabbits. Sodium thiopental infusion in doses of less than 0.3 mg/kg/min into unilateral renal artery caused dose-dependent increases in urine flow, urinary excretion of electrolytes, fractional excretion of sodium and free water clearance with no changes in systemic blood pressure and clearance of p-aminohippuric acid (renal blood flow). An anesthetic dose of sodium thiopental administered intravenously caused decreases in systemic blood pressure, renal hemodynamics, urine flow and free water clearance during the early period of anesthesia followed by increases in urinary excetion of sodium and fractional excretion of sodium. Unilateral renal arterial infusion of sodium thiopental decreased the renin secretion rate and plasma norepinephrine concentration in renal vein, whereas an anesthetic dose of sodium thiopental administered intravenously increased the renin secretion rate. These observations suggest that the diuretic, natriuretic and renin suppressive effects of sodium thiopental may be due to an inhibition of intrarenal sympathetic nervous system or due to a direct tubular action.
Intrarenal Kallikrein-Kinin Activity in Acute Renovascular Hypertension in Dogs
Authors: Verma Pritam S. , Gagnon John A. , Miller Russell L.
Published: November 2008

The intrarenal kallikrein-kinin system was studied during the acute phase of renovascular hypertension induced by renal artery constriction and during teprotide inhibition of kininase II in the dog. Kallikrein-like activity measured by both kininogenase and esterolytic assays, was increased during renal artery constriction (p < 0.5) and (p < 0.01). The administration of teprotide resulted in a further increase of renal cortical kallikrein-like activity and inhibited kininase II activity (p < 0.01). Following the inhibition of kininase II, the plasma concentration of kininogen was also significantly decreased (p < 0.0l). These results suggest that kininase II inhibition may increase levels of intrarenal and plasma kinins and that decreased degradation of kinin peptides may contribute significantly to the acute hypertensive effect of teprotide.
Potent and Selective PPAR-α Agonist LY518674 Upregulates Both ApoA-I Production and Catabolism in Human Subjects With the Metabolic Syndrome
Authors: Millar John S. , Duffy Danielle , Gadi Ramprasad , Bloedon LeAnne T. , Dunbar Richard L. , Wolfe Megan L. , Movva Rajesh , Shah Ashish , Fuki Ilia V. , McCoy Mary , Harris Cynthia J. , Wang Ming-Dauh , Howey Daniel C. , Rader Daniel J.
Published: November 2008

Objective—

The study of PPAR-α activation on apoA-I production in humans has been limited to fibrates, relatively weak PPAR-α agonists that may have other molecular effects. We sought to determine the effect of a potent and highly specific PPAR-α agonist, LY518674, on apoA-I, apoA-II, and apoB-100 kinetics in humans with metabolic syndrome and low levels of HDL cholesterol (C).

Methods and Results—

Subjects were randomized to receive LY518674 (100 μg) once daily (n=13) or placebo (n=15) for 8 weeks. Subjects underwent a kinetic study using a deuterated leucine tracer to measure apolipoprotein production and fractional catabolic rates (FCR) at baseline and after treatment. LY518674 significantly reduced VLDL-C (−38%,
P
=0.002) and triglyceride (−23%,
P
=0.002) levels whereas LDL-C and HDL-C levels were unchanged. LY518674 significantly reduced VLDL apoB-100 (−12%,
P
=0.01) levels, attributable to an increased VLDL apoB-100 FCR with no change in VLDL apoB-100 production. IDL and LDL apoB-100 kinetics were unchanged. LY518674 significantly increased the apoA-I production rate by 31% (
P
<0.0001), but this was accompanied by a 33% increase in the apoA-I FCR (
P
=0.002), resulting in no change in plasma apoA-I. There was a 71% increase in the apoA-II production rate (
P
<0.0001) accompanied by a 25% increase in the FCR (
P
<0.0001), resulting in a significant increase in plasma apoA-II.

Conclusions—

Activation of PPAR-α with LY518674 (100 μg) in subjects with metabolic syndrome and low HDL-C increased the VLDL apoB-100 FCR consistent with enhanced lipolysis of plasma triglyceride. Significant increases in the apoA-I and apoA-II production rates were accompanied by increased FCRs resulting in no change in HDL-C levels. These data indicate a major effect of LY518674 on the production and clearance of apoA-I and HDL despite no change in the plasma concentration. The effect of these changes on reverse cholesterol transport remains to be determined.
Does Continuing Education Improve Physical Therapists’ Effectiveness in Treating Neck Pain? A Randomized Clinical Trial
Authors: Cleland Joshua A , Fritz Julie M , Brennan Gerard P , Magel Jake
Published: November 2008

Background and Purpose

Physical therapists often attend continuing education (CE) courses to improve their overall clinical performance and patient outcomes. However, evidence suggests that CE courses may not improve the outcomes for patients receiving physical therapy for the management of neck pain. The purpose of this study was to investigate the effectiveness of an ongoing educational intervention for improving the outcomes for patients with neck pain.

Participants

The study participants were 19 physical therapists who attended a 2-day CE course focusing on the management of neck pain. All patients treated by the therapists in this study completed the Neck Disability Index (NDI) and a pain rating scale at the initial examination and at their final visit.

Methods

Therapists from 11 clinics were invited to attend a 2-day CE course on the management of neck pain. After the CE course, the therapists were randomly assigned to receive either ongoing education consisting of small group sessions and an educational outreach session or no further education. Clinical outcomes achieved by therapists who received ongoing education and therapists who did not were compared for both pretraining and posttraining periods. The effects of receiving ongoing education were examined by use of linear mixed-model analyses with time period and group as fixed factors; improvements in disability and pain as dependent variables; and age, sex, and the patient's initial NDI and pain rating scores as covariates.

Results

Patients treated by therapists who received ongoing education experienced significantly greater reductions in disability during the study period (pretraining to posttraining) than those treated by therapists who did not receive ongoing training (mean difference=4.2 points; 95% confidence interval [CI]=0.69, 7.7). Changes in pain did not differ for patients treated by the 2 groups of therapists during the study period (mean difference=0.47 point; 95% CI=−0.11, 1.0). Therapists in the ongoing education group also used fewer visits during the posttraining period (mean difference=1.5 visits; 95% CI=0.81, 2.3).

Discussion and Conclusion

The results of this study demonstrated that ongoing education for the management of neck pain was beneficial in reducing disability for patients with neck pain while reducing the number of physical therapy visits. However, changes in pain did not differ for patients treated by the 2 groups of therapists. Although it appears that a typical CE course does not improve the overall outcomes for patients treated by therapists attending that course, more research is needed to evaluate other educational strategies to determine the most clinically effective and cost-effective interventions.
Technology and Perception in Alfred Andersch's Early Poetry and Prose
Authors: Gilfillan Daniel
Published: November 2008

Seit der Erfindung der Maschine, der listigsten aller Waffen gegen die Natur, die überhaupt möglich ist, haben Unternehmer und Erfinder die Zahl der Hände, deren sie bedürfen, im wesentlichen auf deren Herstellung verwendet. Die Arbeit der Maschine wird von der anorganischen Kraft geleistet, der Spannkraft von Dampf oder Gas, der Elektrizität und der Wärme, die aus oder durch Kohle, Erdöl und Wasser befreit werden. Aber damit ist die seelische Spannung zwischen Führern und Geführten gefährlich gewachsen. Man versteht einander nicht mehr. (Spengler 51)
Model for the reconfiguration of specialized vascular services
Authors: Holt P J E , Poloniecki J D , Hinchliffe R J , Loftus I M , Thompson M M
Published: November 2008

Background

This article built on previous work to develop an algorithm for elective abdominal aortic aneurysm (AAA) repair and carotid endarterectomy (CEA), with the aim of improving patient survival by regionalization of services. Vascular procedures were used as an example of specialized surgical services.

Methods

A model was generated based on a national data set that incorporated the statistical demonstration of procedural safety, hospital annual surgical case volume, and travel distance and time. Elective AAA repair was used to construct a hub-and-spoke model that was tested against CEA. The impact of the model was quantified in terms of mortality rates, and travel distance and time.

Results

Only 48 vascular hubs were required to provide adequate coverage in England, with the majority of patients travelling for less than 1 h to access inpatient vascular surgery. The model predicted a reduction in the number of deaths from elective surgery for AAA (P < 0·001) and CEA (P = 0·016).

Conclusion

Adoption of this strategic model may lead to improved outcome after AAA and CEA. It could be used as a model for the regionalization of specialized surgery. The model does not take into account the complexity of providing a comprehensive vascular service in every locality.
Randomized clinical trial of early versus delayed temporary stoma closure after proctectomy (Br J Surg 2008; 95: 693–698)
Authors: Shirazi M H
Published: November 2008

The Editors welcome topical correspondence from readers relating to articles published in the Journal. Responses should be sent electronically via the BJS website (www.bjs.co.uk). All letters will be reviewed and, if approved,appear on the website. A selection of these will be edited and published in the Journal. Letters must be no more than 250 words in length.
Primary percutaneous coronary intervention for acute myocardial infarction caused by unprotected left main stem thrombosis
Authors: Prasad Sandhir B. , Whitbourn Robert , Malaiapan Yuvaraj , Ahmar Walid , MacIsaac Andrew , Meredith Ian T.
Published: November 2008

Background: There is a paucity of data on outcomes in patients undergoing percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI) caused by left main stem (LMS) thrombosis. Objectives: We sought to determine (i) the clinical features, (ii) correlates of early mortality, and (iii) long‐term outcomes in contemporary patients undergoing primary PCI for unprotected LMS thrombosis. Methods: From 1,115 consecutive primary PCI cases at two tertiary referral centers between January 2004 and September 2007, 28 cases (2.5%) with unprotected LMS culprit lesions were identified. Data were obtained from review of institutional databases, folder audit, telephone survey of patients, and independent review of angiograms. Results: The mean age of patients was 68 ± 14 years. Males comprised 76%, and 21% had diabetes. Significant morbidity was noted at presentation: shock in 18 (62%), pulmonary oedema in 15 (52%), and cardiac arrest in 10 (35%) patients, respectively. Lesion location was ostial in 7 (25%), body in 8 (29%), and distal in 13 (46%) patients, respectively. Angiographic success was achieved in 24 patients (83%). Stents were deployed in 27 patients (96%); drug‐eluting stents in 11 patients (39%). No patient required in‐hospital CABG. Cumulative in‐hospital mortality was 36%. Univariate predictors of in‐hospital mortality included shock, preceding cardiac arrest, and angiographic failure (all P < 0.05). At a mean follow‐up of 26 ± 12 months in hospital survivors, there were two TVR (elective CABGs), one death, and no reinfarctions. Conclusion: We report a lower than previously reported in‐hospital mortality of 36% in contemporary patients undergoing primary PCI for unprotected LMS thrombosis. Long‐term outcomes in hospital survivors appear favorable. © 2009 Wiley‐Liss, Inc.
Kinetic anomalies of mixed crystal growth and their effect on the crystal isomorphic composition
Authors: Bocharov S. N. , Gille P. , Glikin A. E.
Published: November 2008

Growth rate anomalies in aqueous solution growth of NaClO3 and KClO3 were first revealed by V. V. Sipyagin in 1967 and attributed to “kinetic anomalies”. These phenomena were confirmed in a series of other studies and for a variety of substances. Therefore, some universality of these anomalies was supposed that should be due to structural transformations in the liquid solutions. In this paper, we present for the first time results on growth rate oscillations found in mixed crystal growth and their impact on the isomorphic composition of solid solutions. Thick (100) Na(Cl,Br)O3 layers were grown at fixed supercooling conditions onto NaClO3 seeds in a microcrystallization cell equipped with an optical microscope. In the temperature range of 33 – 41 °C, four kinetic anomalies were found in solutions of a chlorate: bromate molar ratio of 20: 1 at supercoolings of 2.0 K and 3.0 K. Lattice parameter measurements of the grown Na(Cl,Br)O3 layers revealed a linear dependence of lattice constant vs. growth rate. By measuring Vegard's law (lattice parameter vs. solid solution composition) we were able to determine the oscillations in mixed crystal composition that accompany the kinetic anomalies in solid solution systems. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)