Corpuscles of Stannius and Renal Physiology in the Eel (Anguilla rostrata)

1969 ◽  
Vol 26 (3) ◽  
pp. 639-654 ◽  
Author(s):  
D. G. Butler
Keyword(s):  
Urine Flow ◽  
Renal Physiology ◽  
Calcium Deposition ◽  
Renal Tubules ◽  
Experimental Conditions ◽  
Renal Handling ◽  
Flow Rates ◽  
Corpuscles Of Stannius ◽  
Effective Filtration Pressure ◽  
Plasma Calcium Concentration

In freshwater eels there is a significant correlation between glomerular filtration rates (GFR) and urine flow rates suggesting that changes in GFR rather than tubular water reabsorption lead to the major adjustments in urine flow rates accompanying changes in environmental salinity.Removal of the corpuscles of Stannius was not followed by a significant change in GFR indicating that an adequate (normal) effective filtration pressure is independent of a corpuscular pressor substance.In 8 of 17 Stanniectomised eels urine flow rates exceeded GFR demonstrating that, under these experimental conditions, eel renal tubules secrete water.Multiple tissue electrolyte changes followed Stanniectomy; the 75% increase in the plasma calcium concentration is of particular interest. This increase was probably due to a reduction in the net rate of calcium deposition in bone and not to a change in the renal handling of calcium.

The Role of Vasopressin and Urea in the Renal Concentrating Defect of Patients with Cirrhosis of the Liver

1971 ◽  
Vol 41 (5) ◽  
pp. 441-452 ◽  
Author(s):  
C. A. Vaamonde ◽  
Liliana S. Vaamonde ◽  
J. I. Presser ◽  
H. J. Morosi ◽  
E. L. Klingler ◽  
...  
Keyword(s):  
Urine Osmolality ◽  
Urine Flow ◽  
Cirrhosis Of The Liver ◽  
Urinary Concentration ◽  
Renal Tubules ◽  
Urea Synthesis ◽  
Water Diuresis ◽  
Flow Rates ◽  
Cirrhotic Patients ◽  
Concentrating Defect

1. The maximal urine osmolality in response to vasopressin during water diuresis and during hydropenia was studied in twenty patients with cirrhosis and sixteen noncirrhotic subjects under controlled dietary conditions. 2. The cirrhotic patients exhibited a significantly lower maximal urine osmolality under both experimental conditions. 3. During water diuresis decompensated and compensated cirrhotics had comparable maximal urine osmolalities after vasopressin. A decreased response of the renal tubules to vasopressin does not appear to have a significant role in the concentrating defect. 4. The cirrhotic patients had a significantly lower excretion rate of urea at high (water diuresis) and low (vasopressin antidiuresis or hydropenia) urine flow rates. The lower urine urea concentration accounted for most of the decrease observed in maximal urinary concentration. After vasopressin administration the absolute tubular reabsorption of urea was also significantly lower in cirrhotic patients. The results suggest that a decrease in the medullary urea content decreases medullary osmolality resulting in the defect in urine concentration noted in these cirrhotic patients at low urine flow rates. 5. Protein depletion or decreased urea synthesis may in part be responsible for the decreased availability of urea for the concentrating process in cirrhosis. 6. Lack of correlation between concentrating and diluting capacity in these patients suggested that decreased delivery of sodium to the distal site might not be the limiting factor common to both renal functional abnormalities observed in cirrhosis of the liver.

An anti-settling sample delivery instrument for serial femtosecond crystallography

2012 ◽  
Vol 45 (4) ◽  
pp. 674-678 ◽  
Author(s):  
Lukas Lomb ◽  
Jan Steinbrener ◽  
Sadia Bari ◽  
Daniel Beisel ◽  
Daniel Berndt ◽  
...  
Keyword(s):  
Constant Flow ◽  
Syringe Pump ◽  
Experimental Conditions ◽  
Flow Rates ◽  
X Ray ◽  
Constant Flow Rate ◽  
Significant Impairment ◽  
Working Principle ◽  
After Hours ◽  
Serial Femtosecond Crystallography

Serial femtosecond crystallography (SFX) using X-ray free-electron laser (FEL) sources has the potential to determine the structures of macromolecules beyond the limitation of radiation damage and without the need for crystals of sufficient size for conventional crystallography. In SFX, a liquid microjet is used to inject randomly oriented crystals suspended in their storage solution into the FEL beam. Settling of crystals in the reservoir prior to the injection has been found to complicate the data collection. This article details the development of an anti-settling sample delivery instrument based on a rotating syringe pump, capable of producing flow rates and liquid pressures necessary for the operation of the injector. The device has been used successfully with crystals of different proteins, with crystal sizes smaller than 20 µm. Even after hours of continuous operation, no significant impairment of the experiments due to sample settling was observed. This article describes the working principle of the instrument and sets it in context with regard to the experimental conditions used for SFX. Hit rates for longer measuring periods are compared with and without the instrument operating. Two versions of the instrument have been developed, which both deliver sample at a constant flow rate but which differ in their minimum liquid flow rates and maximum pressures.

Studies on the carbohydrate metabolism of sheep. XVI. Partition of ketone bodies in blood, tissues, and urine

1962 ◽  
Vol 13 (2) ◽  
pp. 307 ◽  
Author(s):  
RL Reid
Keyword(s):  
Renal Clearance ◽  
Blood Level ◽  
Ketone Bodies ◽  
Urine Flow ◽  
Blood Levels ◽  
Renal Tubules ◽  
Hydroxybutyric Acid ◽  
Acetoacetic Acid ◽  
Tissue Concentrations ◽  
Blood Concentrations

Acetone comprised 0–40% (average 18%) of the acetoacetic acid plus acetone fraction in sheep blood, in which the level of this fraction was 0.6–5.2 mg % (as acetone). Acetoacetic acid was largely converted to acetone during storage of blood at –20°C, with intermittent thawing for analysis. Concentrations of acetoacetic acid in red cells were similar to those in plasma, but those of ß-hydroxybutyric acid were considerably lower. In contrast to acetoacetic acid, ß-hydroxybutyric acid was virtually absent from foetal blood and from brain tissue. Concentrations of both ketone fractions in liver and muscle tissue were about one-half the blood concentrations. The renal clearance of acetoacetic acid plus acetone in hyperketonaemic pregnant ewes was independent of blood level up to 20 mg % and was little affected by rate of urine flow. Clearance values were in the range of 4–9 ml per min, which indicates that most of the acetoacetic acid filtered at the glomeruli is absorbed by the renal tubules. Renal clearance of ß-hydroxybutyric acid was dependent on blood level and was more affected by rate of urine flow than that of acetoacetic acid. Very little ß-hydroxybutyric acid appeared in the urine when blood levels were below 15 mg %. Clearance increased as blood concentration rose above this level, and reached maximum values, mostly of 3–5 ml per min, at blood levels exceeding 30 mg %.

Accounting for sensor calibration, concentration heterogeneity, measurement and sampling uncertainties in monitoring urban drainage systems

2003 ◽  
Vol 47 (2) ◽  
pp. 95-102 ◽  
Author(s):  
J.-L. Bertrand-Krajewski ◽  
J.-P. Bardin ◽  
M. Mourad ◽  
Y. Béranger
Keyword(s):  
Performance Indicator ◽  
Sensor Calibration ◽  
Urban Drainage ◽  
Experimental Conditions ◽  
Flow Rates ◽  
Rainfall Events ◽  
Drainage Systems ◽  
Methods And Techniques ◽  
Urban Drainage Systems ◽  
Online Measurements

Assessing the functioning and the performance of urban drainage systems on both rainfall event and yearly time scales is usually based on online measurements of flow rates and on samples of influent and effluent for some rainfall events per year. In order to draw pertinent scientific and operational conclusions from the measurement results, it is absolutely necessary to use appropriate methods and techniques in order to i) calibrate sensors and analytical methods, ii) validate raw data, iii) evaluate measurement uncertainties, iv) evaluate the number of rainfall events to sample per year in order to determine performance indicator with a given uncertainty. Based on previous work, the paper gives a synthetic review of required methods and techniques, and illustrates their application to storage and settling tanks. Experiments show that, despite controlled and careful experimental conditions, relative uncertainties are about 20% for flow rates in sewer pipes, 6-10% for volumes, 25-35% for TSS concentrations and loads, and 18-276% for TSS removal rates. In order to evaluate the annual pollutant interception efficiency of storage and settling tanks with a given uncertainty, efforts should first be devoted to decrease the sampling uncertainty by increasing the number of sampled events.

Renal Function in Unanaesthetized River Lampreys (Lampetra FluviatilisL.): Effects of Anaesthesia, Temperature and Environmental Salinity

1983 ◽  
Vol 105 (1) ◽  
pp. 351-362 ◽  
Author(s):  
A. J. MCVICAR ◽  
J. C. RANKIN
Keyword(s):  
Renal Function ◽  
Flow Rate ◽  
Ventilation Rate ◽  
Urine Flow ◽  
The Body ◽  
Urine Flow Rate ◽  
Flow Rates ◽  
Gill Ventilation ◽  
Daily Excretion ◽  
The Mean

1. Improved estimates of urine flow rates of lampreys in various salinities were obtained by the collection of urine for periods of up to 48 h from minimally-stressed, unanaesthetized fish, following catheterization of the urinogenital papilla. 2. The mean urine flow rate of freshwater lampreys was 200.7 ±14.3 ml kg−1 day−1. 3. Urine flow in freshwater lampreys was correlated with spontaneous changes in gill ventilation rate. MS222 anaesthesia reduced both ventilation and urine flow rates, but pronounced effects were only observed at concentrations greater than those needed to induce light anaesthesia (50–55 mg 1−1). Urine flow rate in unanaesthetized fish was extremely sensitive to rapid (6°Ch−1) changes in temperature and Q10 (6–16°C) was approximately 5. 4. Urine flow rate decreased rapidly as the osmotic difference between the body fluids and environment approached zero, and the rate of flow in 30% seawater lampreys was only 7.6% that of freshwater fish. 5. There was no evidence for an effect of environmental calcium concentration on branchial osmotic permeability. 6. Extensive tubular reabsorption of ions occurred in freshwater lampreys. The total daily excretion rate of sodium ions generally decreased in salinities hyperosmotic to the plasma, indicating enhanced reabsorption, but secretion of magnesium and sulphate ions was greatly increased. Urine osmolarity was significantly increased in lampreys in hyperosmotic salinities. 7. Present data compare favourably with data obtained previously from anaesthetized animals, indicating that renal function in lampreys is not significantly impaired by light MS222 anaesthesia.

Early innervation of the metanephric kidney

Development ◽  
1988 ◽  
Vol 104 (4) ◽  
pp. 589-599 ◽  
Author(s):  
H. Sariola ◽  
K. Holm ◽  
S. Henke-Fahle
Keyword(s):  
Primary Cultures ◽  
Neuronal Cell ◽  
Similar Distribution ◽  
Renal Tubules ◽  
Experimental Conditions ◽  
Tissue Sections ◽  
Neuronal Cell Bodies ◽  
Metanephric Kidney ◽  
Kidney Morphogenesis

During kidney differentiation, the nephrogenic mesenchyme converts into renal tubules and the ureter bud branches to form the collecting system. Here we show that in the early undifferentiated kidney rudiment there is a third cell type present. In whole-mount preparations of cultured undifferentiated metanephric kidneys, neurones can be detected by immunohistochemical means with antibodies against the neurofilament triplet, 13AA8, and against neuronal cell surface gangliosides, Q211. Clusters of neuronal cell bodies can be seen in the mesenchyme close to the ureter bud. The terminal endings of neurites are found around the mesenchymal condensates that later become kidney tubules. A similar distribution of neurites can be revealed in tissue sections of kidney grafts growing in the chicken chorioallantoic membranes. In primary cultures of the ureter bud cells, neurones are constantly present. In another report, we have shown that, in experimental conditions, neurones are involved in regulation of kidney morphogenesis. The present results raise the possibility that neurones of the metanephric kidney may have this function in vivo as well.

Swallowing and urine flow responses of ovine fetuses to 24 h of hypoxia

1994 ◽  
Vol 266 (4) ◽  
pp. R1345-R1352 ◽  
Author(s):  
R. A. Brace ◽  
M. E. Wlodek ◽  
G. J. McCrabb ◽  
R. Harding
Keyword(s):  
Oxygen Saturation ◽  
Arterial Oxygen Saturation ◽  
Recovery Period ◽  
Urine Flow ◽  
Late Gestation ◽  
Arterial Oxygen ◽  
Flow Rates ◽  
Arterial Ph ◽  
Pregnant Sheep ◽  
Fetal Urine

The aim of this study was to determine the effects of 24 h of hypoxia on fetal swallowing and urine flow rates. The study design included successive 24-h control, hypoxia, and recovery periods. To induce hypoxia, we infused nitrogen into the trachea of late-gestation pregnant sheep. During hypoxia, there were decreases in fetal arterial oxygen saturation [from 62.7 +/- 2.2 to 30.9 +/- 2.9% (SE)] and PO2 (from 21.1 +/- 1.0 to 14.1 +/- 0.9 mmHg) (n = 7). Fetal arterial pH decreased maximally by 0.04 +/- 0.01 at 6 h and returned to control thereafter. Fetal swallowing decreased from 13.4 +/- 2.1 to 0.6 +/- 0.2 ml.h-1.kg fetal wt-1 with the onset of hypoxia and gradually increased, but only to one-half control levels, during the last 12 h of hypoxia. Fetal urine flow gradually decreased from 9.6 +/- 1.6 ml.h-1.kg-1 to a minimum of 5.3 +/- 0.5 ml.h-1.kg-1 at 2-3 h of hypoxia and returned to control thereafter. During the first hour of the recovery period, fetal swallowing transiently increased to twice control levels before returning to control. This was followed by a delayed, transient increase in urine flow to 63% above control levels at 2-6 h after hypoxia. We conclude that the fetal swallowing and urine flow responses to prolonged hypoxia in the absence of acidemia are distinctly different from the initial inhibitory responses, in that swallowing partially and urine flow fully recovers from the initial suppression.

Maximum and average urine flow rates in normal children—The miskolc nomograms

1996 ◽  
Vol 31 (3) ◽  
pp. 455
Author(s):  
M.N de la Hunt
Keyword(s):  
Urine Flow ◽  
Normal Children ◽  
Flow Rates

scholarly journals THE PATHOGENESIS OF THE RENAL INJURY PRODUCED IN THE DOG BY HEMOGLOBIN OR METHEMOGLOBIN

1947 ◽  
Vol 86 (4) ◽  
pp. 339-356 ◽  
Author(s):  
H. E. Harrison ◽  
H. Bunting ◽  
N. K. Ordway ◽  
W. S. Albrink
Keyword(s):  
Renal Function ◽  
Kidney Function ◽  
Renal Injury ◽  
Severe Depression ◽  
Urine Flow ◽  
Renal Tubules ◽  
Intravascular Hemolysis ◽  
Direct Measurements ◽  
Tubule Cells ◽  
Concentrated Solution

Severe and persistent impairment of kidney function has been produced in dogs by intravascular hemolysis due to arsine, or by the intravenous injection of solutions of dog hemoglobin and methemoglobin. The kidneys of these animals have been examined by the usual histological methods and also by means of the ferrocyanide histochemical method to determine the pathogenesis of the renal injury. These observations indicate that obstruction to flow of urine through the renal tubules is an important factor in the early reduction of kidney function. The material filling the lumina of the renal tubules was found to be chiefly methemoglobin in concentrated solution of gel-like consistency. No evidence of formation of a pigment insoluble at the pH of the urine such as hemochromogen or hematin was found. The cessation of urine flow is most readily explained by the increased viscosity of the tubule contents. The intravenous administration of methemoglobin was found to produce more severe renal injury than the injection of equal amounts of oxyhemoglobin. Necrosis of the proximal convoluted tubule cells was present as a late lesion in animals injected with methemoglobin, large amounts of hemoglobin, or following extensive intravascular hemolysis. Such injury is probably a contributing factor in the persistent severe depression of renal function seen in these animals. Following disappearance of most of the intratubular pigment, a large number of collapsed tubules lined by hemosiderin-filled cells were found. The ferrocyanide histochemical studies indicated that these represented non-functioning nephrons although no obstructing intratubular material was present. Direct measurements in two animals failed to reveal any reduction of renal blood flow following the injection of methemoglobin in amounts sufficient to produce renal injury.

Kidney structure and function of desert kangaroos

1977 ◽  
Vol 42 (4) ◽  
pp. 636-642 ◽  
Author(s):  
M. J. Denny ◽  
T. J. Dawson
Keyword(s):  
Glomerular Filtration ◽  
Structure And Function ◽  
Urine Flow ◽  
Home Ranges ◽  
Plasma Flows ◽  
Flow Rates ◽  
Kidney Structure ◽  
Red Kangaroo ◽  
And Function

The structure and function of the kidneys of two species of desert kangaroos, the red kangaroo (Megaleia rufa) and the euro (Macropus robustus), were examined. Both kangaroos had glomerular filtration rates (GFR), renal plasma flows, and urine flow rates, when hydrated and dehydrated, which were lower than those of similarly sized eutherian mammals. The differences observed between the two species of marsupials were both structural and functional. The GFR of the red kangaroo was higher than that of the euro, under hydrated and dehydrated conditions, and this was correlated with the occurrence of larger and more numerous glomeruli, particularly juxtamedullary glomeruli, in the red kangaroo. Although the kidney of the euro had a greater relative medullary thickness than that of the red kangaroo, the latter had better urine-concentrating abilities. As opposed to this the euros reabsorbed significantly more urea from the filtrate when dehydrated (89.0%) than did the red kangaroos (69.2%). This ability of the euro to resorb more urea may be related to their tendency to overgraze their restricted home ranges during drought.

Sign in / Sign up

Export Citation Format

Share Document