scholarly journals Gills versus kidney for ionoregulation in the obligate air-breathing Arapaima gigas, a fish with a kidney in its air-breathing organ

2020 ◽  
Vol 223 (20) ◽  
pp. jeb232694
Author(s):  
Chris M. Wood ◽  
Bernd Pelster ◽  
Susana Braz-Mota ◽  
Adalberto L. Val
Keyword(s):  
Kidney Function ◽  
Indirect Evidence ◽  
Ammonia Excretion ◽  
Urine Flow ◽  
Urine Collection ◽  
Air Breathing ◽  
Arapaima Gigas ◽  
Flux Measurements ◽  
Osmorespiratory Compromise ◽  
Very High

ABSTRACTIn Arapaima gigas, an obligate air-breather endemic to ion-poor Amazonian waters, a large complex kidney runs through the air-breathing organ (ABO). Previous indirect evidence suggested that the kidney, relative to the small gills, may be exceptionally important in ionoregulation and nitrogen (N) waste excretion, with support of kidney function by direct O2 supply from the airspace. We tested these ideas by continuous urine collection and gill flux measurements in ∼700 g fish. ATPase activities were many-fold greater in kidney than gills. In normoxia, gill Na+ influx and efflux were in balance, with net losses of Cl− and K+. Urine flow rate (UFR, ∼11 ml kg−1 h−1) and urinary ions (< 0.2 mmol l−1) were exceptional, with [urine]:[plasma] ratios of 0.02–0.002 for K+, Na+, and Cl−, indicating strong reabsorption with negligible urinary ion losses. Urinary [ammonia] was very high (10 mmol l−1, [urine]:[plasma] ∼17) indicating strong secretion. The kidney accounted for 21–24% of N excretion, with ammonia dominating (95%) over urea-N through both routes. High urinary [ammonia] was coupled to high urinary [HCO3−]. Aerial hypoxia (15.3 kPa) and aerial hyperoxia (>40.9 kPa) had no effects on UFR, but both inhibited branchial Na+ influx, revealing novel aspects of the osmorespiratory compromise. Aquatic hypoxia (4.1 kPa), but not aquatic hyperoxia (>40.9 kPa), inhibited gill Na+ influx, UFR and branchial and urinary ammonia excretion. We conclude that the kidney is more important than gills in ionoregulation, and is significant in N excretion. Although not definitive, our results do not indicate direct O2 supply from the ABO for kidney function.

New Source of Dietary Data for Extinct Herbivores

1988 ◽  
Vol 30 (1) ◽  
pp. 92-97 ◽  
Author(s):  
William A. Akersten ◽  
Theresea M. Foppe ◽  
George T. Jefferson
Keyword(s):  
Late Pleistocene ◽  
Indirect Evidence ◽  
Bison Bison ◽  
Large Herbivores ◽  
Usual Assumption ◽  
Microhistological Analysis ◽  
Rancho La Brea ◽  
Very High ◽  
Control Study ◽  
Dietary Data

The teeth of many large herbivores contain “pockets” (fossettes, fossettids, etc.) which entrap impacted samples of food (dental boluses) during mastication. These do not preserve well in most fossil deposits, but at Rancho La Brea, paleobotanical remains survive essentially intact and dental boluses from late Pleistocene forms are amenable to microhistological analysis. Of the identifiable bolus contents, those from Bison antiquus averaged 87% nonmonocotyledons; from Camelops hesternus, 90% nonmonocotyledons; and from Equus occidentalis (one specimen), 56% nonmonocotyledons. A control study on modern Bison bison shows that the boluses contain somewhat lower percentages of monocotyledons than do alimentary samples from the same individuals. However, this accounts for only a part of the very high percentage of nonmonocotyledons in the boluses of the extinct Bison. We conclude that the populations of B. antiquus and C. hesternus represented at Rancho La Brea probably fed little on grasses and that there is enough indirect evidence to suggest that the same may be true for other populations of these taxa. The Equus data are not sufficient to do more than question the usual assumption that Pleistocene horses were always obligate grass eaters.

Kidney Function in the Crab-Eating Frog (Rana Cancrivora)

1962 ◽  
Vol 39 (1) ◽  
pp. 167-177 ◽  
Author(s):  
KNUT SCHMIDT-NIELSEN ◽  
PING LEE
Keyword(s):  
East Asia ◽  
Glomerular Filtration ◽  
Kidney Function ◽  
Sea Water ◽  
Tubular Reabsorption ◽  
Urine Flow ◽  
South East Asia ◽  
Considerable Part ◽  
Osmotic Concentration ◽  
Full Strength

1. A study has been made of kidney function in the crab-eating frog, Rana cancrivora, of south-east Asia. 2. This frog can live in full-strength sea water; in such concentrated media its blood is slightly hypertonic to the medium, and a considerable part of the osmotic concentration is due to urea. 3. In concentrated media the excretion of urea is greatly diminished. This is not due to active tubular reabsorption of urea, but primarily to a low urine flow caused by increased tubular reabsorption of water and reduced glomerular filtration. 4. In concentrated media, as compared with dilute media, only a few percent of the filtered urea appears in the urine. 5. Osmoregulation of the crab-eating frog in sea water resembles that of elasmobranchs except in that there is no evidence of active tubular reabsorption of urea in the frog.

Abstract 14084: Albuminuria and Prognosis Among Individuals With Atherosclerotic Cardiovascular Disease: The Atherosclerosis Risk in Communities (aric) Study

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Yejin Mok ◽  
Shoshana Ballew ◽  
Richard Stacey ◽  
Joseph Rossi ◽  
Silvia Koton ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
High Risk ◽  
Kidney Function ◽  
Risk Group ◽  
High Risk Group ◽  
Composite Outcome ◽  
Clinical Conditions ◽  
Reduced Kidney Function ◽  
Aric Study ◽  
Very High

Background: The AHA/ACC 2018 Cholesterol Guideline categorizes ASCVD patients into very high-risk vs. high-risk to guide intensive therapy. This categorization is based on clinical conditions, including reduced kidney function, but does not take into account albuminuria, the other kidney measure often available in clinical practice. Methods: We studied 838 participants with major ASCVD (myocardial infarction, ischemic stroke, or symptomatic peripheral artery disease) from the ARIC study at baseline (1996 - 98). We compared urine albumin-to-creatinine ratio (ACR) and the eight high-risk conditions of age 65+, reduced kidney function, diabetes, etc. in the AHA/ACC Guideline regarding their associations with composite outcome of all-cause mortality, myocardial infarction, ischemic stroke, and heart failure. We also evaluated risk classification by adding ACR to the eight high-risk conditions. Results: During a median follow-up of 8 years, 724 (86%) participants developed a composite outcome. ACR ≥30 mg/g was associated with the composite outcome (adjusted hazard ratio [aHR] 1.45 [95% CI 1.20, 1.75]) beyond the eight high-risk conditions (aHR of these conditions ranged from 0.96 to 2.46). The addition of ACR improved the c-statistic by 0.011 (95% CI 0.003-0.019) from 0.661 to 0.672. ACR classified 4.6% of high-risk group to very high-risk and 11.2% of very high-risk group to extremely very high-risk with a reasonable calibration (Figure). Even ACR ≥10 mg/g showed a significant aHR of 1.38 (1.17, 1.63) and classified 13.4% of high-risk and 18.1% very high-risk to a higher risk category. Of our patients with ASCVD, 77% had diabetes, hypertension, or low kidney function, clinical conditions in which the ACR assessment is recommended. Conclusions: In ASCVD, albuminuria was a strong predictor of major adverse cardiovascular outcome and improved risk prediction. Clinicians should pay attention to albuminuria, in addition to eGFR, when managing ASCVD patients.

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.

Air-breathing mechanics in two Amazonian teleosts, Arapaima gigas and Hoplerythrinus unitaeniatus

1978 ◽  
Vol 56 (4) ◽  
pp. 939-945 ◽  
Author(s):  
A. P. Farrell ◽  
D. J. Randall
Keyword(s):  
Gas Pressure ◽  
Breathing Patterns ◽  
Air Breathing ◽  
Arapaima Gigas ◽  
Breathing Mechanics ◽  
Replacement Technique ◽  
Hoplerythrinus Unitaeniatus

The mechanics of air breathing in pirarucu, Arapaima gigas, and jeju, Hoplerythrinus unitaeniatus, were studied by simultaneous monitoring of air bladder gas pressure and buccal pressure. Also the effect of alterations in air bladder gas tensions on air-breathing patterns was examined by a gas replacement technique. Pirarucu surface every 4.2 min to make a single ventilation of the air bladder, whilst jeju usually make two or three ventilations at an air breath every 3.0 min. Pirarucu exhale first, then inhale, but in jeju buccal filling occurred before lung emptying. Inhalation in pirarucu is a result of air bladder aspiration combined with the action of a buccal pump; however, lung filling in jeju is achieved by a buccal pump only. The significance of aspiration breathing in pirarucu is discussed. Both fish respond similarly to alterations in air bladder gas tensions. Hyperoxia prolongs the interval between air breaths and hypercapnia reduces this interval.

scholarly journals Estimating Kidney Function in the Critically Ill Patients

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Gemma Seller-Pérez ◽  
Manuel E. Herrera-Gutiérrez ◽  
Javier Maynar-Moliner ◽  
José A. Sánchez-Izquierdo-Riera ◽  
Anibal Marinho ◽  
...  
Keyword(s):  
Critically Ill ◽  
Kidney Function ◽  
Kidney Injury ◽  
Laboratory Method ◽  
Urine Flow ◽  
Critically Ill Patient ◽  
Functional Evaluation ◽  
Common Definition ◽  
Definition Of ◽  
Near Future

Glomerular filtration rate (GFR) is an accepted measure for assessment of kidney function. For the critically ill patient, creatinine clearance is the method of reference for the estimation of the GFR, although this is often not measured but estimated by equations (i.e., Cockroft-Gault or MDRD) not well suited for the critically ill patient. Functional evaluation of the kidney rests in serum creatinine (Crs) that is subjected to multiple external factors, especially relevant overhydration and loss of muscle mass. The laboratory method used introduces variations in Crs, an important fact considering that small increases in Crs have serious repercussion on the prognosis of patients. Efforts directed to stratify the risk of acute kidney injury (AKI) have crystallized in the RIFLE or AKIN systems, based in sequential changes in Crs or urine flow. These systems have provided a common definition of AKI and, due to their sensitivity, have meant a considerable advantage for the clinical practice but, on the other side, have introduced an uncertainty in clinical research because of potentially overestimating AKI incidence. Another significant drawback is the unavoidable period of time needed before a patient is classified, and this is perhaps the problem to be overcome in the near future.

Some kinetic properties of skeletal muscle pyruvate kinase from air-breathing and water-breathing fish of the Amazon

1978 ◽  
Vol 56 (4) ◽  
pp. 751-758 ◽  
Author(s):  
J. H. A. Fields ◽  
W. R. Driedzic ◽  
C. J. French ◽  
P. W. Hochachka
Keyword(s):  
Skeletal Muscle ◽  
Pyruvate Kinase ◽  
Adenosine Diphosphate ◽  
Kinetic Properties ◽  
Air Breathing ◽  
Hoplias Malabaricus ◽  
Arapaima Gigas ◽  
Saturation Kinetics ◽  
Muscle Pyruvate Kinase ◽  
Hoplerythrinus Unitaeniatus

The kinetic properties of pyruvate kinase from skeletal muscle were studied in two species of air-breathing fish, Hoplerythrinus unitaeniatus and Arapaima gigas, and two species of water-breathing fish, Hoplias malabaricus and Osteoglossum bicirrhosum. It was found that the enzymes from Hoplias and Hoplerythrinus showed hyperbolic saturation kinetics for all substrates, were activated slightly by fructose 1,6-diphosphate, and were inhibited by phosphocreatine and citrate. The enzyme from Hoplias was inhibited by alanine, whereas the enzyme from Hoplerythrinus was not. The enzymes from Arapaima and Osteoglossum showed hyperbolic saturation kinetics for adenosine diphosphate, but the saturation kinetics for phusphoenol-pyruvate were sigmoidal. These enzymes were strongly activated by fructose 1,6-diphosphate and strongly inhibited by alanine, the former completely reversing the inhibition by the latter. Phosphocreatine and citrate were also found to be inhibitors of these enzymes, but the inhibition by phosphocreatine was not reversed by additions of fructose 1,6-diphosphate. The enzymes from the water-breathing fish were more sensitive to inhibition by alanine than were those from the air-breathing fish, but in other respects the enzymes were very similar.

Sign in / Sign up

Export Citation Format

Share Document