bluuebunny/crossref_metadata_2025 huggingface dataset:
Clock Drawing Test in Mild Cognitive Impairment: Quantitative Analysis of Four Scoring Methods and Qualitative Analysis
Authors: Lee Kang Soo , Kim Eun A , Hong Chang Hyung , Lee Dong-Woo , Oh Byoung Hoon , Cheong Hae-Kwan
Published: November 2008

Background: The role of the clock drawing test (CDT) as a screening tool for dementia has been evaluated. However, studies focusing on mild cognitive impairment (MCI) are still lacking. The purpose of this study was to verify the validity of the CDT as a screening method for MCI. Methods: 524 subjects aged 60 years and older were recruited in the community. Of these, 241 were diagnosed as not cognitively impaired (NCI) and 224 were classified as MCI. The CDT was scored according to the Freedman, Rouleau, Todd, and CERAD CDT and an additional comprehensive scoring system incorporating elements of most CDT for qualitative analysis. Results: The sensitivity and specificity of the 4 CDT scoring systems for MCI ranged from 40.7 to 56.4% and from 71.8 to 85.3%, respectively. The likelihood ratio and the positive and negative predictive values of the 4 CDT ranged from 18 to 29, 18.2 to 24.5 and from 55.9 to 78.4%, respectively. In qualitative analysis, a significantly lower performance in the clock numbers category was observed in the MCI group. Conclusion: This study suggests that although some qualitative analyses could help in identifying MCI individuals, the CDT is insufficient as a screening method to distinguish MCI individuals from NCI individuals in a clinical setting.
Differential Hypometabolism Patterns according to Mild Cognitive Impairment Subtypes
Authors: Jauhiainen Anne M. , Kangasmaa Tuija , Rusanen Minna , Niskanen Eini , Tervo Susanna , Kivipelto Miia , Vanninen Ritva L. , Kuikka Jyrki T. , Soininen Hilkka
Published: November 2008

Aims: The present study investigated cerebral glucose metabolism and structural atrophy in controls and subjects with mild cognitive impairment (MCI). Methods: The study included 13 controls, 7 MCI subjects considered as prodromal Alzheimer’s disease (MCI of the Alzheimer type, aMCI) and 7 MCI subjects having cognitive decline due to other causes, established by clinical evaluation (MCI of the non-Alzheimer type, naMCI). Glucose metabolism in the frontal, parietal and posterior cingulate cortices, the hippocampus and parahippocampal gyrus was evaluated using Statistical Parametric Mapping 2 (SPM2). Structural analysis of the whole-brain grey matter was performed with voxel-based morphometry in SPM2. Results: Significant hypometabolism was found in the medial temporal lobe in aMCI subjects compared to the controls and naMCI subjects. In addition, both the aMCI and naMCI patients had hypometabolism of the posterior cingulum relative to controls. The naMCI subjects showed atrophy of frontal and occipital areas compared to controls and aMCI patients, whereas the aMCI subjects did not show atrophy compared to the other groups. Conclusion: aMCI subjects have reduced glucose uptake levels, particularly in areas susceptible to pathological changes in Alzheimer’s disease, and the changes are more pronounced in aMCI than naMCI subjects. Our results also suggest that functional changes may be more prominent than structural changes in MCI.
The Fat Content of Small Primary Breast Cancer Interferes with Radiofrequency-Induced Thermal Ablation
Authors: Athanassiou E. , Sioutopoulou D. , Vamvakopoulos N. , Karasavvidou F. , Tzovaras G. , Tziastoudi E. , Sakellariou M. , Hatzitheofilou C.
Published: November 2008

Background: Radiofrequency (RF) thermal ablation is a minimally invasive technique of local mass elimination with variable efficiency. Methods: Ten patients with small primary breast cancer diagnosed preoperatively by core needle biopsy were ablated percutaneously by an RF (Radionics Cool-tip) device operating on impedance control mode. The percent fat-containing area was calculated in each slide of a total of 47 slides introduced to IQ materials software image analysis. Results: Seven of 10 tumors with tumor diameter less than 2.8 cm and fat content less than 12.47% were totally ablated (score 3). One of 10 with 3 cm tumor diameter and 5.45% fat content showed an intermediate degree of ablated tissue (score 2), and the last 2 with 2 cm and 2.2 cm tumor diameter and more than 19.74% tumor fat content were minimally ablated (score 1). Our present exploratory study on 10 patients suggests dependence of the degree of thermal damage on tumor fat content. Conclusions: We conclude that the fat content of small primary breast cancer could serve as a ‘heat sink’ and should be considered as a preventing factor of complete local tumor destruction by RF thermal ablation.
Atresia of Proximal Coronary Arteries in Pulmonary Atresia with Intact Ventricular Septum – Fetal and Neonatal Findings
Authors: Sarkola Taisto , Boldt Talvikki , Happonen Juha-Matti , Karikoski Riitta , Eronen Marianne
Published: November 2008

Pulmonary atresia with intact ventricular septum (PA+IVS) is a rare congenital cardiac malformation which is associated with ventriculocoronary arterial communications from the right ventricle. We present a case of PA+IVS with a bilateral atresia of the coronary ostia, and thus, a completely right ventricular-dependent coronary circulation followed up by fetal echocardiography. Eventually the infant died of myocardial infarction at 2 days of age.
Sex Difference in the Prevalence of Left Ventricular Hypertrophy in Dialysis Patients
Authors: Cheng Li-Tao , Gao Yan-Li , Tian Jun-Ping , Gu Yue , Zhang Li , Bi Shu-Hong , Tang Wen , Lindholm Bengt , Wang Tao
Published: November 2008

Background: Left ventricular hypertrophy (LVH) is an important, independent negative predictor of cardiovascular morbidity and mortality in the general population and in dialysis patients. Previous studies suggest a sex dimorphism in the prevalence of LVH; however, this issue has never been approached in dialysis patients. Methods: This study enrolled 237 prevalent dialysis patients: 49 on hemodialysis (HD) and 188 on peritoneal dialysis (PD) from a single center. LVH was defined by echocardiography measurements, which were normalized to body surface area (BSA) and height2.7, respectively. Results: The mean ages in HD and PD patients were 60 ± 14 and 60 ± 13 years, with a median dialysis vintage of 43 and 20 months, respectively. Although there was no significant difference in age, diabetes, proportion of uncontrolled hypertension, antihypertensive medication and blood pressure between male and female patients within each dialysis modality, the prevalence of LVH (whether indexed to BSA or height2.7) was consistently higher in females than in males. When these patients were divided into LVH or non-LVH groups, a significant difference in sex distribution was observed between the two groups (62.0% vs. 41.0% when the BSA-indexed standard was used, p < 0.01; 62.8% vs. 37.1% when the height2.7-indexed standard was used, p < 0.001). In logistic regression analysis, female sex was identified as a risk factor of LVH (odds ratio, OR = 2.48, 95% confidence interval, CI = 1.33–4.59; when BSA-indexed LVH was treated as dependent variable, and OR = 4.05, 95% CI = 1.96–8.38, when height2.7-indexed LVH was treated as dependent variable) even after adjustment for age, diabetes, blood pressure and antihypertensive medication. Conclusion: This study showed that the prevalence of LVH determined by echocardiography was significantly higher in female dialysis patients than in male dialysis patients. Compared with males, female patients had a 2.5- to 4-fold higher risk to develop LVH even after adjustment for other potential confounding factors, which may indicate that elderly females in the uremic scenario are more prone to develop LVH than elderly males.
Drug-Eluting Coronary Stents: Hypersensitivity Reactions to Paclitaxel
Authors: Pfoch L. , Mahler V. , Sticherling M.
Published: November 2008

Background: Drug-eluting stents become increasingly popular for the treatment of coronary artery disease. Consequently, side effects including hypersensitivity reactions have to be anticipated. Case Report: Here we report on a patient with an anaphylactic reaction 2 weeks after implantation of a polymer-based paclitaxel-eluting stent (Taxus™, Boston Scientific). The patient presented with disseminated wheals, pruritus, bronchial asthma and acute synovitis. The reaction was successfully treated with initial intravenous injection followed by oral antihistamine treatment for 1 month until all stent-bound paclitaxel was assumed to be eluted. Thereafter no further anaphylactic reaction occurred. Conclusion: This sequence of events points towards a causal relation of the stent implantation and hypersensitivity reaction with a central role of paclitaxel. The increasing use of this type of stent should therefore be carefully monitored for such adverse reactions.
Impaired Response to Vasopressin of Adenylate Cyclase of the Thick Ascending Limb of Henle’s Loop in Brattleboro Rats with Diabetes insipidus
Authors: Imbert-Teboul Martine , Chabardès Danielle , Montégut Madeleine , Clique André , Morel François
Published: November 2008

Brattleboro rats with diabetes insipidus (DI) exhibit an impaired urinary concentrating ability in response to exogenous vasopressin (AVP) and a decreased AVP-sensitive adenylate cyclase (AC) in homogenates of kidney medulla. To further analyze this phenomenon, AC responses to AVP were measured in medullary segments of the thick ascending limb of Henle’s loop (MAL) and the collecting tubule (MCT), microdissected from DI and control rats of the same strain. AVP dose-response curves determined in MCT from DI and control rats were identical, indicating that, in that nephron segment, the enzyme response to the hormone was normal in DI rats. In contrast, AC activities measured simultaneously in MAL were on the average 50% lower (p, < 0.001) in DI than in control rats for all AVP concentrations tested. The apparent affinity constant of enzyme activation by the hormone was similar in both groups of animals. These results suggest that the concentrating defect of DI rats in the presence of AVP could result from a subnormal AC responsiveness to AVP selectively affecting MAL.
Effect of Acute Parathyroidectomy on Sodium, Bicarbonate and Water Reabsorption in Partially Nephrectomized Rats with Hyperparathyroidism
Authors: Bank Norman , Su Wei-Shing , Aynedjian Hagop S.
Published: November 2008

Sodium and bicarbonate reabsorption was measured in proximal tubules of remnant kidneys of rats with secondary hyperparathyroidism (NX rats). In 7 of 15 NX rats, parathyroidectomy (PTX) was carried out 1 h before starting micropuncture study (NX-PTX rats). Bicarbonate reabsorption was measured over a range of plasma HCO-3 concentrations from 20 to 60 mEq/1. TF/Phcct3 was significantly lower in NX and NX-PTX than in control rats, and proximal HCO-3 reabsorption was higher. PTX did not significantly alter proximal sodium or HCO-3 reabsorption. In contrast, acute PTX decreased fractional excretion of Na+, HCO-3, and H20 in the final urine. These findings suggest that PTH may inhibit electrolyte and water reabsorption beyond the proximal tubule in the kidney with a reduced nephron mass.
Glomerular Filtration Rate and Urine Concentration in the Dromedary Camel in Dehydration
Authors: Yagil R. , Berlyne G.M.
Published: November 2008

The glomerular filtration rate (GFR), effective renal plasma flow (ERPF), urine osmolality, urine flow rate, urea excretion, osmolar clearance, and free water reabsorption were measured in a group of 5 female dromedary camels in control conditions and also after 10 days dehydration in both early and mid-summer. There was a loss of 23% in mean body weight and a fall of 75% in GFR in severe dehydration, with a parallel reduction in ERPF and in urine flow rate. Urine osmolality reached a mean maximum of 1,466 mosm/kg in severe dehydration of mid-summer, the highest individual urine osmolality being 2,372 mosm/kg. Osmolar clearance, free water absorption and urinary urea excretion were lower in dehydration. Urea/inulin clearance ratio was significantly lower in dehydration (p < 0.001). Sodium excretion did not change in dehydration. Fractional reabsorption of urea was higher in dehydration, reaching a maximum value of 74% of the filtered load. The fall in urinary urea concentration was one of the factors contributing to the poor concentrating ability of the severely dehydrated camel kidney, probably caused by the fall in GFR and increase in tubular reabsorption of urea, rather than by protein deprivation.
Catheterization of the Renal Artery for in vivo Infusion of the Kidney in the Cat
Authors: Krausz Michael M. , Ophir Avinoam , Feuerstein Giora
Published: November 2008

A special cannula for direct intrarenal artery injections has been prepared from a 19-gauge Intracath®. This cannula (with its stylet) possesses a proper degree of flexibility in spite of its small caliber (o.d. 0.40 mm, i.d. 0.26 mm).The surgical procedure, which involves catheter insertion to one renal artery through the stump of the opposite renal artery, can be accomplished over a short period of time with essentially no blood loss This method affords an opportunity of studying the effect of various drugs directly injected into the isolated kidney in vivo. No changes in plasma renin concentration was observed in the animals after renal artery cannulation. This method enables chronic cannulation of the renal artery.
In vitro Production of a Natriuretic Material of Renal Origin
Authors: Godon J.P. , Dechenne C.
Published: November 2008

Glomerular and tubular epithelial cells from salt-loaded normal and glomerulonephritic rats and from salt-depleted normal rats were cultured in 199 medium. Supernatants from cultures after 3, 7, 17 and 23 days provided molecular weight fractions similar to those previously found to contain natriuretic activity in plasma and urine. When tested in a bioassay system, extracts isolated from culture supernatants from normal ‘salt-loaded’ tubular cells produced a significant natriuretic effect but did not modify overall glomerular filtration rate and renal plasma flow. No natriuretic activity was observed with supernatants removed from culture of the epithelial cells prepared in the other conditions.
Effect of Acute Metabolic Acidosis on the Levels of some Metabolic Intermediates in the Rat Kidney
Authors: Bennett Franklyn I. , Alleyne George A.O.
Published: November 2008

Rats were sacrificed 30 min, 1 and 2 h after a single dose of ammonium chloride and metabolite levels were measured in quick frozen kidneys. The most striking finding was the early depression of glutamate, 2-oxoglutarate, malate, phosphoenolpyruvate and glycerol-3-phosphate. At the end of 2 h, 2-oxoglutarate and malate still remained depressed but glutamate, phosphoenolpyruvate and glycerol-3-phosphate had returned to normal levels. The results cannot be explained on the basis of acceleration or inhibition of a single enzyme but possibly represent a general effect of pH and/or bicarbonate.
Studies on Intrarenal Prostaglandins
Authors: Iihoshi Motohiro , Mitsuzaki Hisashi , Tsuruta Kazuma , Yamamoto Toshihiro , Ikegami Keiichi
Published: November 2008

Prostaglandins (PGs) E2 and F2α in the rabbit kidney were determined in order to study the effects of unilateral ureteral occlusion for periods up to 6 weeks. A significant increase of PGE2 concentration in the inner medulla of the obstructed kidney was always observed after ureteral occlusion of more than 24 h. In the contralateral kidney, PGE2 in the inner medulla gradually decreased in proportion to the period of ureteral occlusion. The present results suggest that the enhanced PGE2 may be a protective mechanism initiated to overcome the renal vasoconstriction after unilateral ureteral occlusion.
Renal Function during Contralateral Arterial or Ureteral Obstruction
Authors: Bartoli Ettore , Conger John D. , Earley Laurence E.
Published: November 2008

Excretory function of one kidney of the rat was reduced acutely by either partial renal arterial occlusion, elevation of ureteral pressure or complete ligation of the renal pedicle. UNa·V by the opposite kidney increased approximately twofold during partial arterial occlusion or elevated ureteral pressure and this was not associated with increased kidney or superficial nephron glomerular filtration rate (GFR). Absolute proximal reabsorption fell during contralateral arterial constriction, parallel to a drop in GFR. The calculated delivery of filtrate out of proximal tubules rose when natriuresis occurred during the experimental maneuvers and decreased parallel to sodium excretion when obstruction or clamping of the opposite kidney was released. Unilateral ligation of the renal pedicle did not result in changes in nephron filtration rate or proximal tubular reabsorption, although urine flow rate rose, attended by a smaller and nonsignificant natriuresis: in this latter circumstance a distal fall in Na transport may be postulated, while the former experimental maneuvers could have caused an increase in Na excretion by a proximal effect. Thus, contralateral natriuresis during partial unilateral reduction in renal function may be due to different factors, specifically related to the experimental maneuver used to lower GFR.
EC Collagen: Biosynthesis by Corneal Endothelial Cells and Separation from Type IV without Pepsin Treatment or Denaturation
Authors: Benya Paul D.
Published: November 2008

Primary cultures of rabbit corneal endothelial cells were labeled with proline and the medium proteins were fractionated by sedimentation through sucrose density gradients. A new collagen, endothelial cell (EC) collagen, was completely separated from type IV collagen without denaturation by this technique. Sodium dodecyl sulfate electrophoresis demonstrated EC collagen fragments of 180K, 120K, and 60K daltons. Prior pepsin treatment produced only the 60K fragment after electrophoresis. The cyanogen bromide peptide pattern of the 180K EC peptide demonstrated that EC was different from type IV. A preliminary structural model for the largest helical form (∼ 540K daltons) of EC collagen is presented.
Composition and Biosynthesis of Glomerular Basement Membrane in Rats Fed Diets Rich in Sucrose
Authors: Price Robert G. , Kang Sarwan S. , Taylor Sarah A. , Khalil-Manesh Farhad , Yudkin J.
Published: November 2008

1-month-old Sprague-Dawley rats were fed synthetic diets containing 55% sucrose (SU) or starch (ST) as the sole source of carbohydrate for 2, 3 or 8 months. Both the ST and SU fed rats gained weight normally, but SU fed rats had enlarged kidneys. A higher yield of glomerular basement membrane (GBM) was recovered from 9-month-old SU rats. An increase in the hydroxylated amino acid content was found in GBM prepared from SU fed rats and the glycine content was also higher. The increase in the hydroxylation of lysine was accompanied by increased glycosylation and there was 30% more Glc-Gal-Hyl present in GBM from 9-month-old SU rats. GBM was solubilised with sodium dodecyl sulphate (SDS) and 2-mercaptoethanol and subjected to electrophoresis on 5% polyacrylamide gels. There was an apparent fall in the intensity of the bands with molecular weights greater than 200,000 and a concomitant rise in low molecular weight components (50,000–100,000) in GBM from 4-month-old SU rats. These differences between ST and SU membrane were accentuated when the membranes from 9-month-old rats were compared. No significant differences were found in the glucosyl transferase activities of renal cortical homogenates prepared from 3-month-old SU and ST rats, but the activities in SU rats were significantly higher at 4 and 9 months. The feeding of SU-rich diets to rats induces a number of biochemical changes in the kidney which are similar to those found in diabetes. The feeding of SU diets provides a useful animal model with which to study the effect of dietary carbohydrate on renal GBM. SU should not be included in diets fed to diabetic rats because of the similarity of some of its effects and those seen in chemically induced diabetes.
Chemical Characterization of Glomerular and Tubular Basement Membranes of Various Mammalian Species
Authors: Langeveld J.P.M. , Veerkamp J.H.
Published: November 2008

A graded sieving procedure was used to isolate both glomeruli and tubules from renal cortex of cattle, pig, sheep, horse, man and rat. In addition, tubules from rabbit renal cortex were isolated. Glomerular and tubular basement membranes (GBM and TBM, respectively) were obtained with a detergent procedure. Purity of preparations was established with light and electron microscopy and by estimating total phosphorus content. Amino acid and carbohydrate compositions of the basement membranes were determined and statistically evaluated. Chemical composition of the preparations of all species was typical for renal basement membranes. Significant species-dependent variations were found, however, for many chemical constituents. Comparison of the chemical composition of GBM with TBM as pairs from individuals showed as a common phenomenon in all species that GBM preparations contain more of the heteropolysaccharide constituents, especially twice as much neuraminic acids than TBM preparations. Observed differences may be related to variations in immunogenic properties of the different types of renal basement membranes.
Role of Basal Lamina in Tissue Interactions
Authors: Brownell Anna G. , Slavkin Harold C.
Published: November 2008

Basal lamina are extracellular structures found closely apposed to the plasma membrane on the basal surface of epithelial and endothelial cells and surround muscle and fat tissues. While the primary function of basal lamina in most adult tissues is probably supportive, significant evidence indicates that during embryonic development, basal lamina may be involved in regulating heterotypic tissue interactions. Changes in composition of the basal lamina of salivary and mammary gland epithelial tissues during development probably are important for branching morphogenesis which leads to the final form of the organ. During tooth organogenesis, selective basal lamina degradation and direct cell contact between developing epithelium and mesenchyme has been documented and suggested to be necessary for cytodifferentiation. Basal lamina turnover, as suggested by these morphological observations, no doubt involves both basal lamina synthesis and degradation. We have studied several factors evidently required for basal lamina reconstitution in vitro, and have discovered that fibronectin added to enamel organ epithelial cultures provided cues required for basal lamina formation in vitro. Both fetal calf serum and dental papilla mesenchyme-conditioned media also provided specific signals for basal lamina reconstitution. In addition, we have found that fibronectin is produced by the dental papilla mesenchyme, is released into the medium, and can be isolated from epithelial explants which have been cultured in mesenchyme-conditioned medium; the epithelial explants themselves do not make fibronectin in vitro.
Human Platelets and Glomerular Basal Lamina Interaction
Authors: Huang Thomas W. , Benditt Earl P.
Published: November 2008

Collagen is one of the major constituents of glomerular basal lamina. Its thrombogenecity has been systematically studied in our laboratory by aggregometry, adenine nucleotide release assay, and electron microscopy. The purified human glomerular basal lamina (HGBL) preparation does not induce platelet degranulation, nucleotide release, or aggregation, although adhesion and spreading of platelets on HGBL are observed. Isolated monomeric HGBL collagen or insoluble HGBL collagen in its native state of organization are similarly inactive. Modification of carbohydrate moieties by sialase, alpha-glucosidase, alpha-glucosidase, or sodium periodate oxidation has no effect on HGBL’s inability to induce platelet release reaction or aggregation. Therefore, HGBL collagen is not thrombogenic as has been suspected. Adhesion and spreading of platelets on HGBL, which require the noncollagen constituents of HGBL and divalent cations, represent a temporary capillary pavement for endothelial defect distinct from thrombogenic activity of platelets.
On the Pathogenesis of Glomerulonephritis
Authors: Sanders Eric , Davies Malcolm , Coles Gerald A.
Published: November 2008

Lysosomal proteinase activity was assayed in urines from 157 patients with renal disease. 16 were found to be excreting acid and neutral proteinases. 15 of these 16 had a severe proliferative glomerulonephritis with polymorphonuclear leucocyte (PMN) infiltration of the glomeruli. These same 16 patients excreted excess quantities of glomerular basement membrane (GBM) antigen. Only urines with neutral proteinase activity were capable of degrading GBM in vitro. Clinical recovery was accompanied by disappearance of both proteinases and excess GBM fragments from the urine. Detailed studies on one patient showed that the neutral proteinase activity was, at least in part, due to PMN lysosomal elastase. Calculation shows that in these patients enough PMN neutral proteinase was present in the glomeruli to cause significant GBM damage.
Specificity and Nephrotoxicity of Heterologous Antibodies Directed Against Renal Basement Membranes
Authors: Rakotoarivony J. , Orfila J.C. , Dubois C. , Bardos P. , Muh J.P. , Mahieu P. , Suc J.M.
Published: November 2008

Two immune sera have been raised in sheep against rabbit glomerular and tubular basement membranes, respectively (GBM and TBM). Their specificity was investigated by immunoabsorption and radioimmunoassay, and their nephrotoxicity was studied by injecting them into New Zealand rabbits. Both antisera reacted in vitro collagen and noncollagen-related glycopeptides. However, while the anti-GBM antiserum reacted preponderantly with GBM and TBM collagen which probably represent the antigen(s) shared by the two basement membranes, the anti-TBM antiserum was directed preferentially against the noncollagenous component of rabbit TBM. The anti-GBM antiserum induced in rabbits a diffuse extracapillary glomerulonephritis with linear fixation of autologous IgG and C3 along the GBM. The anti-TBM antiserum also induced an extracapillary glomerulonephritis but in addition a focal tubular atrophy was seen and autologous IgG and C3 were fixed along both GBM and TBM and glucosuria frequently occurred. These results suggested that the glomerular lesions induced by the two antisera were due to anticollagen antibodies while the tubulointerstitial lesions were due to antibodies directed against the noncollagenous portion of TBM.
Significance of Glomerular C3b Receptors in Human Renal Diseases
Authors: Colasanti G. , Moran J. , Bellini A. , D’Amico G.
Published: November 2008

In order to elucidate their role in mediating renal immune injury in man, the glomerular C3b receptors have been analyzed in frozen sections of 205 kidneys biopsied from 199 patients affected by various well-defined renal diseases. Using fluoresceinated C3b-coated bacteria as the indicator system, the receptor activity has been compared with that found in 10 normal human kidneys. In 76 out of 98 cases (77%) of glomerulonephritis (GN) with capillary wall abnormalities, a significant loss of receptor activity has been observed. No difference was present between the 89 patients affected by GN presumably due to immune complexes (ICX) parietal deposition (membranoproliferative, membranous, acute poststreptococcal GN and proliferative GN of SLE and cryoglobulinemia) and the 9 patients affected by GN presumably due to anti-GBM antibodies (Goodpasture’s syndrome and extracapillary GN). In the group of ICX-GN, no correlation could be demonstrated between inhibition of C3b receptors and the presence of parietal C3 deposits. A significant loss of receptors activity has been also demonstrated in 12 out of 13 patients with amyloidosis or diabetic glomerulosclerosis. On the contrary, inhibition of C3b receptors has been observed in only 3 out of 20 patients with nonglomerular renal diseases (interstitial and vascular nephropathies) and in only 11 out of 57 patients (19%) affected by mesangial GN with no capillary wall abnormalities (Berger’s disease, Henoch-Schonlein purpura and mesangial GN of SLE). C3b receptors were normal in 13 out of 17 patients affected by lipoid nephrosis (minimal change GN or focal glomerulosclerosis). In conclusion, the analysis of C3b receptors in renal diseases do not support the hypothesis of their involvement in parietal localization of C3b-bearing ICX: these results rather suggest that the receptors become undetectable in many glomerular diseases (immune-mediated or not) with lesions of capillary walls, because of the loss of integrity of C3b receptor-bearing visceral epithelial cells.
Capsular Basement Membrane Alterations after Tubulus Atrophy and Glomerulosclerosis in the Dog Kidney
Authors: Schneider Peter
Published: November 2008

After K2HPO4 had been given to beagle dogs orally at a dose of 0.8 g/kg body weight for 14–38 weeks disseminated atrophy of the proximal tubule was apparent. As a result of this process glomerular alterations occur which develop via various stages of inflammation into glomerulosclerosis. Electron microscope findings of particular interest were obtained in the parietal epithelial cells and their basement membrane (BM). Ergastoplasma-rich epithelial cells often have organelle-free intracytoplasmic zones which contain solely microfilamentous and finely flocculent BM-like material. Such regions often appear lacuna-like and are sharply demarcated from the remaining cytoplasma. These areas are in close topographical contact with the parietal BM. The parietal epithelial cells make contact with the BM through dense bundles of filaments. These contacts resemble hemidesmosomes. We also found comparable relationships between epithelial cells and the BM in the proximal tubules. We are convinced that the conditions which we have described in the intracellular production of a material which is similar to the BM and the attachment of these areas onto the BM by filament bundles and hemidesmosomes represent sequestrations and extrusion of BM material. We believe that these could be pathological secretory processes of dedifferentiated epithelial cells.
Effects of Glucocorticoid Administration on Urinary Albumin Excretion by the Normal Kidney
Authors: Zager Richard A.
Published: November 2008

In an effort to elucidate mechanisms by which glucocorticoids enhance urinary protein excretion, albumin and lysozyme excretion patterns were studied in normal rats which had been subjected to a variety of experimental protocols. On the basis of these studies the following conclusions were reached: (1) The acute administration of glucocorticoids produces an immediate increase of both glomerular nitration rate (GFR) and of urinary albumin and lysozyme excretion rates. (2) A delayed albuminuric response to glucocorticoids occurs 14–32 h after drug administration. This second period of albuminuria is quantitatively far more significant than the acute albuminuric response and it occurs at a time when GFR is not statistically different from control experimental animals. (3) Lysozyme excretion 14–32 h following glucocorticoid administration is normal, suggesting an intact tubular protein reabsorption mechanism at the time of maximal albuminuria. (4) The delayed albuminuric period cannot be acutely reproduced by infusion of 5 ml of serum harvested from dexamethasone pretreated albuminuric rats. (5) Dietary Na intake (and presumed activity of the renin/angiotensin axis) does not appear to influence the magnitude of the glucocorticoid-induced albuminuric reaction. Further work is needed to more fully delineate the pharmacologic pathway by which glucocorticoids affect urinary protein excretion and to ascertain whether this response differs between the normal and pathologic kidney.
Glomerular Basement Membrane: Lamina rara, Lamina densa
Authors: Martinez-Hernandez Antonio , Marsh Christine A. , Horn Janet F. , Munoz Eliana
Published: November 2008

Electron immunohistochemical and histochemical studies of glomerular and tubular basement membranes were undertaken to elucidate the relationship between lamina rara and lamina densa. Our results indicate that the lamina rara is not a fixation artifact and it has common antigenic determinants with lamina densa (type IV collagen antigens). Therefore, lamina rara has to be considered an integral component of basement membranes, and biochemical preparations containing only lamina densa should not be considered representative of the whole basement membrane.
The Production of Monoclonal Antibodies against Glomerular and Other Antigens of the Human Nephron
Authors: Falkenberg Frank W. , Müller Edelgard , Riffelmann Hans-Dieter , Behrendt Brigitte , Waks Tova
Published: November 2008

During our studies on human kidney tubular antigens we have applied the technique of cell fusion for the preparation of monoclonal antibodies. For this purpose, plasma membranes were prepared from human kidney cortex by homogenization, fractionated on density gradients and selected according to brush border marker enzyme activity. Spleen cells from Balb/c mice hyperimmunized with plasma membranes were fused (PEG) with NS1 plasmocytoma cells by standard procedure. Culture supernatants were tested for presence of specific antibodies by indirect immunofluorescence with fluorescein-conjugated rabbit anti-mouse Fab antibodies on human kidney slices. In two fusions (210 wells), 70 positive hybrids were found secreting antibodies for a variety of antigens in the kidney. Most of them were directed against tubular antigens. In addition, as a by-product, we detected hybridomas which secreted antibodies specific for antigens in other parts of the nephron, such as glomeruli, blood vessels and the interstitium. 20 individual clones have been isolated so far by soft agar cloning, and monoclonal antibodies were produced in large amounts from ascitic fluid. Some of these antibodies are specific for antigens of the basement membrane, others for antigens of the mesangium. Some recognize antigens present on glomeruli alone, others recognize antigens present on glomeruli and tubules or on glomeruli and blood vessels. We are convinced that the new immunological technique will yield better information on the antigenic microstructure of the nephron. In addition, the monoclonal and, by definition, monospecific antibodies might be useful for diagnostic purposes: recognition and quantitation of the corresponding antigens in the serum and/or urine of patients suffering from kidney diseases.
Effects of Glipizide on Water and Electrolyte Handling in Water-Loaded Humans
Authors: Preuss Harry G. , Rodelas Raul , Terlinsky Alan , Gelfand Michael
Published: November 2008

Renal handling of H2O, Na, and K during H2O diuresis was studied in the same healthy subjects on two occasions, after the administration of either 5 mg of the sulfonylurea, glipizide, or a placebo. Following glipizide, there was no significant overall change in creatinine clearance and the calculated rate of distal Na + K delivery (CH2O + C(Na+K)) in 9 individuals. However, the clearance of free water (CH2O) and the mean fraction of Na + K reabsorbed at the diluting site increased significantly from 8.5 ± (SEM) 0.8 to 9.8 ± (SEM) 0.8 ml/min/100 ml GFR (p < 0.02) and from 55 ± (SEM) 6 to 67 ± (SEM) 7% (p < 0.05), respectively. The mean rate of total Na and K excretion fell following glipizide (p < 0.05). Our results, in conjunction with the results from similar type studies, suggest that ingestion of glipizide and other sulfonylureas that lack antidiuretic properties increase CH2O, at least in part, by augmenting ion reabsorption at the diluting sites of the nephron.
Molecular Sieve in Rat Tubular Basement Membrane as Revealed by Negative Staining
Authors: Makino Hirofumi , Ota Zensuke , Takaya Yasumasa , Miyoshi Akira , Ofuji Tadashi
Published: November 2008

Rat tubuli were isolated both by the method of Krisko and by a modified method of Cook and Pickering; renal tubular basement membrane (TBM) was isolated by sonic disruption and by the method of Carlson. Using electron microscopy after negative staining, TBM of rat kidney isolated under these different conditions was shown to be a fine meshwork. Strands of the meshwork were interwoven, apparently enclosing pores to make up whole basement membrane. These findings are compared with our previous observation that glomerular and alveolar basement membranes were made up of a similarly fine meshwork.
Effect of Potassium on p-Aminohippurate Transport in Rat Kidney Cortex Slices
Authors: Hayashi Hiromu , Hoshi Takeshi
Published: November 2008

The effects of medium K+ concentration on the tissue uptake of p-aminohip-purate (PAH) were investigated in rat kidney cortex slices. K+ concentration in the incubation medium was changed in the absence of Na+. Increase in K+ concentration up to 145 mM revealed an augmenting effect on PAH uptake when tissue water content was controlled at about 72% by elevating medium osmolarity with mannitol. The K+-induced enhancement of PAH uptake was almost completely abolished by the simultaneous presence of extremely high concentration of hippurate. Anoxia reduced this augmenting effect. Pyruvate added to the medium scarcely affected this augmenting effect. The uptake rate during the initial 10-min incubation increased linearly in proportion to the increase in log [K]o /[K]i. The results suggest that high medium K+ concentration stimulates PAH transport by a carrier-mediated process which is dependent on oxidative metabolism. However, the mode of action of K+ on PAH uptake seems to be different from that of Na+. It seems likely that K+ exerts its effect on PAH transport by the alteration of the peritubular membrane potential.
Effect of Exogenous Adenosine 3´:5´-Cyclic Monophosphate, Parathyroid Hormone and Acetazolamide on Electrolyte Hormone and Acetazolamide on Electrolyte Excretion by the Isolated Perfused Rat Kidney
Authors: Besarab Anatole , Pomerantz Philip , Swanson John W.
Published: November 2008

The effects of exogenous adenosine 3´: 5´-cyclic monophosphate (cyclic AMP), parathyroid hormone (PTH) and acetazolamide (Az) on renal calcium and phosphate excretion of the isolated perfused rat kidney were compared. Both PTH and Az evoked an early increase in urinary cyclic AMP excretion followed by a later more prolonged increase in phosphate excretion. All of the increased urinary cyclic AMP was derived from renal cells. Calcium excretion decreased with PTH but was unchanged with Az. Sodium and potassium excretion increased with Az but not PTH. Transitory urinary cyclic AMP excretion rates following bolus additions of exogenous cyclic AMP to perfusate were up to twentyfold greater than those evoked by PTH or Az but unassociated with changes in calcium, phosphate, sodium or potassium excretion. Sustained perfusate levels (above 0.5 µM) and excretion rates of cyclic AMP induced phosphaturia proportional to the perfusate cyclic AMP concentrations achieved up to 2.0 µM. Clearances of exogenous cyclic AMP exceeded inulin clearance at perfusate concentrations greater than 1.0 µM. Aminophylline evoked a small phosphaturia which increased further on addition of cyclic AMP to 5 µM. Glomerular filtration was not affected by any of the agents except Az. Since increased phosphate excretion could be evoked only at perfusate concentrations exceeding either plasma or intracellular concentrations observed in vivo, it is concluded that circulating cyclic AMP at levels in vivo is unlikely to mediate a significant fraction of the renal effects of PTH.
Tubuloglomerular Feedback Response after Hypotensive Hemorrhage
Authors: Kaufman James S. , Hamburger Robert J. , Flamenbaum Walter
Published: November 2008

The tubuloglomerular feedback (TGF) response was studied in control rats and after either hypotensive hemorrhage or aortic clamping (AC). TGF was assessed both by differences in proximally and distally determined single nephron glomerular filtration rate (SNGFR) and by proximally determined SNGFR responses to orthograde microperfusion at 0 or 36 nl/min. Hypotensive hemorrhage was induced by the removal of blood equivalent to 0.5–1% of body weight. In control rats, proximal SNGFR was 29.74 ± SE 0.87 nl/min and distal SNGFR was 28.64 + 0.82 nl/min, values not significantly different from each other. After moderate hemorrhagic hypotension (MH; BP=86 ± 1 mm Hg) or AC (BP=70 ± 4 mm Hg), both proximal and distal SNGFR decreased, with no significant differences between the values in either group. After severe hemorrhagic hypotension (SH; BP=70 ± lmm Hg), proximal SNGFR was 25.23 + 2.07 nl/min and distal SNGFR was 19.69 + 1.50 nl/min, values significantly different from each other and consistent with an enhanced feedback response. Using orthograde microperfusion, a significant reduction in SNGFR at a perfusion rate of 36 nl/min was observed under all circumstances. However, with SH hypotension the percent change in SNGFR at the two perfusion rates was significantly increased to 35.0+5.5%, compared to 21.6 + 6.6% in controls. In contrast, AC with reduction in renal perfusion pressure to a degree comparable to SH hypotension did not augment the relative decrease in SNGFR, the percentage change being 22.2 + 7.2%. Neither was TGF enhanced after MH hypotension when similar volumes of blood were removed but a similar decrease in BP was not obtained. These results suggest that some factor related to severe systemic hypotension enhanced the TGF response.
Intracellular pH in Intact Rat Renal Cortex Estimated with [14 C]-5 5-Dimethyl-2 4-Oxazolidinedione
Authors: Jones Bernard , Simpson David P.
Published: November 2008

The distribution of [14 C]-5 5-dimethyl-2 4-oxazolidinedione ([14 C]-DMO) was measured in intact rat renal cortex using 22Na+ to estimate extracellular fluid volume. Results of two different methods to obtain tissue were compared, a cortical slice technique and a whole kidney frozen technique. In normal animals with a mean blood pH of 7.41 + 0.006 (SEM) the cortical slice method measured an intracellular pH of 6.97 + 0.03 (SEM). Corrections are described which can be used to compensate for varying volumes of tubular fluid in the slice and for differing concentrations of intracellular sodium. Using reasonable estimates for tubular fluid volume and intracellular sodium these corrections increase the value of intracellular pH to about 7.20. The results of the study indicate that the cortical slice [14C]-DMO method provides a satisfactory technique to obtain baseline values for intracellular pH in intact renal cortex, which can be used to detect changes in intracellular pH produced by experimental manipulations.
An Analysis of the Optimal Conditions for Perfusing an Isolated Rabbit Kidney with Homologous Blood
Authors: Pacini Brandani , Bocci V.
Published: November 2008

Isolated rabbit kidneys were perfused in a closed-circuit system with a number of media such a Krebs-Henseleit bicarbonate buffer with albumin, homologous platelet-free plasma, serum and whole blood. All of these media were unsatisfactory. In contrast, fresh blood deprived of platelets, leukocytes, floating lipoproteins, microaggregates and micro-clots did not cause vasoconstriction of the isolated kidney. Renal blood flow, glomerular filtration rate, urinary flow and glucose, cations and renal water reabsorption were approximately normal.
Early Changes of Guanylate Cyclase and cGMP Phosphodiesterase Activities in Glomeruli and Tubules Isolated from the Remaining Kidney after Unilateral Nephrectomy in the Rabbit
Authors: Yusufi Ahad N K , Dancona Carlos , Nguyen Jean-Louis , Helwig Jean-Jacques
Published: November 2008

Guanylate cyclase (GCase) and cyclic guanosine 3’5’-monophosphate-phosphodiesterase (cGMP-PDE) activities were measured in the medulla, glomeruli and cortical tubules isolated from the remaining kidney 5-120 min after unilateral nephrectomy. The results showed that cGMP-PDE-specific activities were unchanged in all the fractions isolated from the contralateral kidney when compared with the nephrectomized control kidney. The GCase-specific activity in the cortical and medullary tubules isolated from the remaining kidney reached a maximum by 10 min after unilateral nephrectomy and then returned to control values. On the other hand the glomerular GCase activity decreased for 10 min after unilateral nephrectomy, then rebound activity reached a maximum by 30 min and after 120 min had returned to the control value. The possible physiological signification of such variations is discussed.
Potentiation of Beta-Adrenergic Effects on Plasma Renin Concentration by Pentobarbital Anesthesia
Authors: Carvalho Jaime S. , Cherkes Joseph K.
Published: November 2008

Potentiation of renin release can be achieved by combining adrenergic stimulation and renal vasodilatation. To examine whether pentobarbital anesthesia influences plasma renin concentration (PRC) by its vasodilatory effect, experiments were performed in rats subjected to increasing levels of adrenergic activity. PRC was two- to fourfold higher in anesthetized than in conscious rats when the beta-adrenoceptor agonist isoproterenol HC1 (0.05–3.2 µg kg-1 min-1) was infused. The sympathomimetic agent tyramine suppressed and the alpha-adrenoceptor blocker phenoxybenzamine enhanced to the same extent the isoproterenol-stimulated PRC in conscious and anesthetized animals. Chronic renal denervation did not abolish the isoproterenol-pentobarbital synergistic effect on PRC. These results are consistent with the view that the renin response to pentobarbital anesthesia is somehow related to the vascular effects of the anesthetic.
Intramembranous Particle Clusters in Collecting Duct Cells of Rats
Authors: Edwards Brian R. , Harmanci Cem
Published: November 2008

Despite the absence of vasopressin, Brattleboro homozygous (DI) rats can concentrate their urine to hypertonic levels when deprived of drinking water. When DI rats are infused with vasopressin, freeze-fracture electron microscopy has revealed increases in intramembranous particle clusters (IPC) in papillary collecting duct luminal membrane that parallel the rise in urine osmolality. In the present study, we examined whether the increase in concentrating ability of DI rats dehydrated for 24 h was associated with a change in IPC. For comparison, oral water loading and 24-hour dehydration were used to suppress and stimulate endogenous vasopressin secretion in Long-Evans (LE) rats, and the effects on urine osmolality and IPC were examined. In LE rats, the induced changes in water balance resulted in alterations in IPC frequency that paralleled urine osmolality, whereas, in DI rats, frequency of IPC remained low under all conditions, even when urine osmolality rose to almost 1,000 mosm/kg H2O as a result of 24-hour dehydration. These results suggest that the increased concentrating ability of dehydrated DI does not depend upon increased water permeability of the papillary collecting ducts.
Renal Hemodynamic Effects of Captopril in Anesthetized Sodium-Restricted Dogs
Authors: Carmines Pamela K. , Rosivall László , Till Margaret F. , Navar Gabriel
Published: November 2008

The mechanism of captopril-induced alterations in arterial pressure (AP), glomerular filtration rate (GFR), renal blood flow (RBF), and renal vascular resistance (RVR) was studied in pentobarbital anesthetized sodium-restricted dogs. In 7 dogs, captopril caused decreases in AP (16 ± 3%) and RVR (46 ± 5%), as well as increases in RBF (62 ± 12%) and sodium excretion (399 ± 73%). These responses were reversed by angiotensin II infusion at a rate sufficient to restore RBF to control levels. The captopril-induced increase in GFR (29 ± 8%) was partially reversed by the intravenous angiotensin II infusion to a level not significantly different from control. In 5 dogs, indomethacin increased AP (10 ± 2%) and RVR (38 + 8%); the slight decreases in RBF and GFR were not statistically significant. Subsequent captopril treatment decreased AP (20 ± 3%) and RVR (42 ± 4%), while RBF and GFR increased by 45 ± 8% and 32 ± 10%, respectively. These observations suggest that the renal response to captopril in sodium-restricted dogs is not dependent upon alterations in prostaglandin synthesis but, instead, is primarily due to diminished angiotensin II activity.