scholarly journals The kidney of the Nodularia freshwater mussel has a larger filtration-size and counter-current system with improved water excretion compared with the seawater mussel Mytilus

Biology Open ◽  
2021 ◽  
Author(s):  
Eriko Seo ◽  
Hidefumi Wakashin ◽  
Yoshiteru Seo
Keyword(s):  
Current System ◽  
Single Layer ◽  
Freshwater Mussel ◽  
Renal Tubules ◽  
Water Excretion ◽  
Pericardial Cavity ◽  
T1 Relaxation ◽  
Distal Tubules ◽  
And Function ◽  
Counter Current

Histological studies and magnetic resonance imaging were employed to analyze the kidney structure and function of the freshwater mussel, Nodularia douglasiae. The Nodularia kidney consists of proximal, intermediate and distal tubules. The epithelia of the renal tubules were composed of a single layer of cuboidal cells. The proximal and distal tubules run in opposite directions underneath the pericardial cavity. Molecular weight cut-off (MWCO) values for the kidney filtration were detected by MR tracer injections: gadolinium-diethylenetriamine pentaacetic acid (GdDTPA) at 0.55 kDa, an oligomer-based contrast agent (CH3-DTPA-Gd) at 2.2kDa, as well as Gd-DTPA-polylysine at 10, 22, and 110 kDa. The T1w-MRI intensity and T1 relaxation rate (R1) of the pericardial cavity and renal tubules increased with tracers smaller than 10 kDa. The other tracers showed only minimal or no increase. Thus, we concluded that the MWCO of the kidney is 22 kDa, 50 times larger than that for the Mytilus living in seawater. Since the R1 values of the renal tubules were similar to those of the pericardial cavity, the kidney did not concentrate filtrated tracers. The slow decay of the MR tracers from the renal tubules indicated a low filtration rate, suggesting that the counter-current system reabsorbs useful solutes without reabsorption of water. The higher MWCO may be beneficial to maintain the tubular oncotic pressure and allow excretion of excess water. In conclusion, a main renal function of the freshwater mussel is the excretion of water, opposite to that of the seawater mussel and vertebrates, which preserve water.

scholarly journals Endothelium as a Source and Target of H2S to Improve Its Trophism and Function

Antioxidants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 486
Author(s):  
Valerio Ciccone ◽  
Shirley Genah ◽  
Lucia Morbidelli
Keyword(s):  
Endothelial Dysfunction ◽  
Vessel Wall ◽  
Redox Reactions ◽  
Single Layer ◽  
Fine Tuning ◽  
Therapeutic Approaches ◽  
Impaired Wound Healing ◽  
Blood Fluidity ◽  
And Function ◽  
And Control

The vascular endothelium consists of a single layer of squamous endothelial cells (ECs) lining the inner surface of blood vessels. Nowadays, it is no longer considered as a simple barrier between the blood and vessel wall, but a central hub to control blood flow homeostasis and fulfill tissue metabolic demands by furnishing oxygen and nutrients. The endothelium regulates the proper functioning of vessels and microcirculation, in terms of tone control, blood fluidity, and fine tuning of inflammatory and redox reactions within the vessel wall and in surrounding tissues. This multiplicity of effects is due to the ability of ECs to produce, process, and release key modulators. Among these, gasotransmitters such as nitric oxide (NO) and hydrogen sulfide (H2S) are very active molecules constitutively produced by endotheliocytes for the maintenance and control of vascular physiological functions, while their impairment is responsible for endothelial dysfunction and cardiovascular disorders such as hypertension, atherosclerosis, and impaired wound healing and vascularization due to diabetes, infections, and ischemia. Upregulation of H2S producing enzymes and administration of H2S donors can be considered as innovative therapeutic approaches to improve EC biology and function, to revert endothelial dysfunction or to prevent cardiovascular disease progression. This review will focus on the beneficial autocrine/paracrine properties of H2S on ECs and the state of the art on H2S potentiating drugs and tools.

scholarly journals RECIRCULACIÓN DE LÍQUIDOS RESIDUALES EN LA CONVERSIÓN DE ALGINATO DE CALCIO EN ÁCIDO ALGÍNICO DURANTE EL PROCESO DE PRODUCCIÓN DE ALGINATOS

2005 ◽  
Vol 20 (1-2) ◽  
pp. 1
Author(s):  
Y. E. Rodríguez-Montesinos ◽  
G. Hernández-Carmona ◽  
D. L. Arvizu-Higuera
Keyword(s):  
Calcium Alginate ◽  
Alginic Acid ◽  
Current System ◽  
Macrocystis Pyrifera ◽  
Alginate Production ◽  
Yield And Quality ◽  
Alginate Fibers ◽  
Counter Current ◽  
Very High

Se estudió el efecto de recircular la solución ácida residual en la etapa de conversión de alginato de calcio en ácido algínico, utilizando el alga Macrocystis pyrifera . Los líquidos residuales fueron reciclados en un sistema en contra corriente, con lo cual se logró procesar tres cargas de alginato de sodio con el mismo volumen de agua, permitiendo una conversión efectiva en ácido algínico, con una reducción del 56% en el consumo de agua dulce. Se experimentó un sistema de recirculación en línea (sin reemplazo de agua), este sistema no es recomendable, debido a que la acumulación de calcio en el alginato después de la segunda recirculación, produce una viscosidad aparente muy alta, con un porcentaje de reducció superior al 50%. Se determinó el efecto del número de lavados ácidos del ácido algínico sobre la calidad y rendimiento del alginato obtenido. El tratamiento ácido se llevó a cabo con tres, dos y un lavado. Se concluye que se requieren tres lavados de las fibras de alginato de calcio para lograr una conversión efectiva en ácido algínico, pero el primero y segundo lavado se pueden hacer con ácido reciclado. Es tesis tema representa un ahorro del 66% en el consumo de agua en esta etapa. Recycling of residual liquids from the conversion of calcium alginate to alginic acid during alginate production process The effect of recycling the residual acid solution from the conversion of calcium alginate to alginic acid from the alga Macrocystis pyrifera was studied. The residual liquid was recycled using a counter current system; it was possible to treat three batches of calcium alginate with the same amount of water, with an effective conversion into alginic acid, saving 56% of fresh water. An inline recycling system was experimented (without water replacement). This system is not recommended, because the large increase of calcium in the alginate after the second recycling, produces a very high apparent viscosity. Using this system the viscosity was reduced in more than 50%. We experimented the effect of the number of acid washings of the alginic acid, on the yield and quality of the final alginate. The acid treatment was carried out with three, two and one washing. It was concluded that three acid washings of the calcium alginate fibers are necessary to obtain an effective conversion of calcium alginate to alginic acid, but the first and second washings can be carried out with recycled acid. This system represents a water saving up to 66% in this step.

Vasopressin-independent alterations in renal water excretion in quadriplegia

1993 ◽  
Vol 265 (2) ◽  
pp. R460-R466 ◽  
Author(s):  
B. M. Wall ◽  
H. H. Williams ◽  
D. N. Presley ◽  
J. T. Crofton ◽  
L. Share ◽  
...  
Keyword(s):  
Cervical Spinal Cord ◽  
Free Water ◽  
Renal Tubules ◽  
Erect Posture ◽  
Free Water Clearance ◽  
Water Excretion ◽  
Vasopressin Release ◽  
Control Subjects ◽  
Cord Injury ◽  
Healthy Control

Postural effects on water excretion are known to be increased in patients with cervical spinal cord injury and may result in marked impairment of the ability to excrete a water load, especially in erect posture. Both vasopressin-dependent and vasopressin-independent mechanisms have been implicated. To assess the roles of these mechanisms and further identify the factors involved in the renal response to erect posture, sustained water loading studies were performed on 11 quadriplegic subjects and 9 healthy control subjects, supine and erect (sitting). Renal blood flow was assessed by p-aminohippurate clearance (CPAH) measurements in 7 quadriplegic and 5 control subjects. During maximal water diuresis, plasma vasopressin concentrations were reduced to unquantifiable levels in all subjects. Osmolar clearance, free water clearance (CH2O), and distal delivery of filtrate (DDF) were all lower in quadriplegic than in control subjects, supine and erect. The relationship between CH2O and DDF was the same in quadriplegic as in control subjects and was not altered by change in posture in either group. Creatinine clearance and CPAH were lower in erect than in supine posture in quadriplegic subjects but not in control subjects. We conclude that impairment of water excretion in stable normonatremic quadriplegic subjects can be attributed primarily to vasopressin-independent mechanisms involving reduced filtrate delivery to diluting segments of the renal tubules rather than to resistance to normal suppression of vasopressin release.

Effects of constituent amino acids on tubular handling of microinfused angiotensin II

1978 ◽  
Vol 234 (4) ◽  
pp. F325-F331 ◽  
Author(s):  
T. N. Pullman ◽  
F. A. Carone ◽  
S. Oparil ◽  
S. Nakamura
Keyword(s):  
Amino Acids ◽  
Angiotensin Ii ◽  
Aspartic Acid ◽  
Free Amino ◽  
Renal Tubules ◽  
Urinary Recovery ◽  
Proximal Tubular ◽  
Distal Tubules ◽  
Proximal Convolution ◽  
Hydrolysis Of

[14C]angiotensin II ([14C]AII) was microinjected alone or with excess L-isoleucine (IIe) or L-aspartic acid (Asp) into renal tubules of anesthetized rats. Urinary excretion of 14C-labeled material was measured, and the intact peptide and its metabolites were identified and quantified. When isoleucine was administered with [14C]AII, urinary recovery of the 14C-labeled material increased directly with distance of infusion site from glomerulus, and most of the radioactivity in urine was [14C]Ile. The data suggest that isoleucine interfered with reabsorption of [14C]Ile derived from hydrolysis of [14C]AII and less so with the hydrolysis itself. When aspartic acid was administered with [14C]AII into the proximal 5/6 of the proximal convolution, total urinary recovery of the 14C-labeled material was unchanged, but percentage of recovery as [14C]AII increased; with infusion into the distal 1/6 of the proximal convolution, total urinary recovery of the 14C labele increased. The data suggest that aspartic acid interfered with the enzymatic hydrolysis of [14C]AII and reabsorption of isoleucine. In distal tubules the 14C label was almost completely recovered as intact [14C]AII in all protocols. The results show that free amino acids influence proximal tubular handling of small linear peptides in rats.

EFFECTS OF DEOXYCORTICOSTERONE ACETATE AND CORTISONE ON THE EXCRETION OF HYPOTONIC SALINE BY ADRENALECTOMIZED RATS

1954 ◽  
Vol 11 (3) ◽  
pp. 261-268 ◽  
Author(s):  
D. F. COLE
Keyword(s):  
Antidiuretic Hormone ◽  
Hormone Secretion ◽  
The Body ◽  
Renal Tubules ◽  
Water Diuresis ◽  
Deoxycorticosterone Acetate ◽  
Water Excretion ◽  
Normal Water ◽  
Hypotonic Saline ◽  
Adrenalectomized Rats

SUMMARY The response to loads of hypotonic saline has been investigated in intact and in adrenalectomized rats treated with deoxycorticosterone acetate, with cortisone acetate and with both steroids. The response of untreated adrenalectomized animals was also studied. Intact rats excreted more water than sodium during the 5 hr after loading with hypotonic saline. There was a reduction of the proportion of water reabsorbed in the renal tubules, but the proportion of sodium reabsorbed was unaltered. Adrenalectomized rats, either with or without deoxycorticosterone treatment, did not show this diuretic response, and there was evidence that sodium was lost from the body cells. Rats in these two groups reabsorbed a smaller proportion of sodium in their renal tubules than intactrats. Adrenalectomized rats treated with cortisone showed partial restoration of the ability to excrete water, but the renal loss of sodium was greater than in intact animals. Treatment of adrenalectomized rats with both cortisone and deoxycorticosterone restored water excretion to normal values, but excessive amounts of sodium were lost. In neither group which received cortisone was there any indication of loss of cell sodium. The response of rats in the group receiving both steroids was not a normal water diuresis because the animals were unable to excrete water without loss of sodium. It appeared unlikely that there was excessive antidiuretic hormone activity in the rats receiving cortisone and that some factor other than reduction of pituitary antidiuretic hormone secretion was essential for normal water diuresis.

scholarly journals Stromal cell–derived factor-1 and hematopoietic cell homing in an adult zebrafish model of hematopoietic cell transplantation

Blood ◽  
2011 ◽  
Vol 118 (3) ◽  
pp. 766-774 ◽  
Author(s):  
Tiffany J. Glass ◽  
Troy C. Lund ◽  
Xiaobai Patrinostro ◽  
Jakub Tolar ◽  
Teresa V. Bowman ◽  
...  
Keyword(s):  
Cell Transplantation ◽  
Stromal Cell ◽  
Hematopoietic Cell Transplantation ◽  
Hematopoietic Cells ◽  
Hematopoietic Cell ◽  
Renal Tubules ◽  
Adult Zebrafish ◽  
Stromal Cell Derived Factor ◽  
Cell Niche ◽  
And Function

Abstract In mammals, stromal cell–derived factor-1 (SDF-1) promotes hematopoietic cell mobilization and migration. Although the zebrafish, Danio rerio, is an emerging model for studying hematopoietic cell transplantation (HCT), the role of SDF-1 in the adult zebrafish has yet to be determined. We sought to characterize sdf-1 expression and function in the adult zebrafish in the context of HCT. In situ hybridization of adult zebrafish organs shows sdf-1 expression in kidney tubules, gills, and skin. Radiation up-regulates sdf-1 expression in kidney to nearly 4-fold after 40 Gy. Assays indicate that zebrafish hematopoietic cells migrate toward sdf-1, with a migration ratio approaching 1.5 in vitro. A sdf-1a:DsRed2 transgenic zebrafish allows in vivo detection of sdf-1a expression in the adult zebrafish. Matings with transgenic reporters localized sdf-1a expression to the putative hematopoietic cell niche in proximal and distal renal tubules and collecting ducts. Importantly, transplant of hematopoietic cells into myelosuppressed recipients indicated migration of hematopoietic cells to sdf-1a–expressing sites in the kidney and skin. We conclude that sdf-1 expression and function in the adult zebrafish have important similarities to mammals, and this sdf-1 transgenic vertebrate will be useful in characterizing the hematopoietic cell niche and its interactions with hematopoietic cells.

Role of Antidiuretic Hormone in Impaired Urinary Dilution Associated with Chronic Bile-Duct Ligation

1980 ◽  
Vol 58 (6) ◽  
pp. 493-500 ◽  
Author(s):  
O. S. Better ◽  
G. A. Aisenbrey ◽  
T. Berl ◽  
R. J. Anderson ◽  
W. A. Handelman ◽  
...  
Keyword(s):  
Bile Duct ◽  
Antidiuretic Hormone ◽  
Bile Duct Ligation ◽  
Diluting Segment ◽  
Water Excretion ◽  
Duct Ligation ◽  
Normal Mean ◽  
And Function ◽  
Distal Delivery

1. The effect of chronic bile-duct ligation on systemic and renal haemodynamics and on the capacity to dilute the urine was studied in conscious rats. Sham-operated rats served as controls. 2. In the rats with bile-duct ligation, the maximal urinary diluting capacity was impaired, despite an expanded plasma volume, a normal mean arterial pressure and cardiac output, and normal intrarenal determinants of water excretion including distal delivery of fluid and function of the diluting segment. 3. In contrast, maximal urinary dilution capacity was intact in rats with congenital central diabetes insipidus and chronic bile-duct ligation. 4. It is concluded that the defect in urinary dilution in rats with chronic bile-duct ligation is dependent on antidiuretic hormone.

The structure of steroids and their diffusion through blood vessel walls in a counter-current system

Steroids ◽  
1984 ◽  
Vol 43 (3) ◽  
pp. 293-303 ◽  
Author(s):  
John A. McCracken ◽  
Willfried Schramm ◽  
Niels Einer-Jensen
Keyword(s):  
Blood Vessel ◽  
Current System ◽  
Vessel Walls ◽  
Counter Current

scholarly journals Drosophila melanogaster NEP2 is a new soluble member of the neprilysin family of endopeptidases with implications for reproduction and renal function

2005 ◽  
Vol 386 (2) ◽  
pp. 357-366 ◽  
Author(s):  
Josie E. THOMAS ◽  
Caroline M. RYLETT ◽  
Ahmet CARHAN ◽  
Nicholas D. BLAND ◽  
Richard J. BINGHAM ◽  
...  
Keyword(s):  
Renal Function ◽  
Drosophila Melanogaster ◽  
Renal Tubules ◽  
Large Expansion ◽  
Evolutionarily Conserved ◽  
Cyst Cells ◽  
Structural Differences ◽  
And Function ◽  
Restricted Pattern ◽  
Binding Subsites

The mammalian neprilysin (NEP) family members are typically type II membrane endopeptidases responsible for the activation/inactivation of neuropeptides and peptide hormones. Differences in substrate specificity and subcellular localization of the seven mammalian NEPs contribute to their functional diversity. The sequencing of the Drosophila melanogaster genome has revealed a large expansion of this gene family, resulting in over 20 fly NEP-like genes, suggesting even greater diversity in structure and function than seen in mammals. We now report that one of these genes (Nep2) codes for a secreted endopeptidase with a highly restricted pattern of expression. D. melanogaster NEP2 is expressed in the specialized stellate cells of the renal tubules and in the cyst cells that surround the elongating spermatid bundles in adult testis, suggesting roles for the peptidase in renal function and in spermatogenesis. D. melanogaster NEP2 was found in vesicle-like structures in the syncytial cytoplasm of the spermatid bundles, suggesting that the protein was acquired by endocytosis of protein secreted from the cyst cells. Expression of NEP2 cDNA in D. melanogaster S2 cells confirmed that the peptidase is secreted and is only weakly inhibited by thiorphan, a potent inhibitor of human NEP. D. melanogaster NEP2 also differs from human NEP in the manner in which the peptidase cleaves the tachykinin, GPSGFYGVR-amide. Molecular modelling suggests that there are important structural differences between D. melanogaster NEP2 and human NEP in the S1′ and S2′ ligand-binding subsites, which might explain the observed differences in inhibitor and substrate specificities. A soluble isoform of a mouse NEP-like peptidase is strongly expressed in spermatids, suggesting an evolutionarily conserved role for a soluble endopeptidase in spermatogenesis.

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