Evidence for Cl−-dependent K+ secretion by the blood–testis barrier of brook trout

1988 ◽  
Vol 66 (7) ◽  
pp. 1603-1609 ◽  
Author(s):  
William S. Marshall ◽  
Sharon E. Bryson
Keyword(s):  
Brook Trout ◽  
Transepithelial Transport ◽  
High Concentration ◽  
Sperm Duct ◽  
K Secretion ◽  
Net Flux ◽  
Mucosal Side ◽  
Blood Testis Barrier

The transepithelial transport of 86Rb+, a tracer for K+, was examined in the isolated sperm duct of brook trout (Salvelinus fontinalis). Fluxes of 86Rb+ at 1.0 mM Rb+ in voltage-clamped ducts bathed with Ringer's solution on both sides revealed net secretion of Rb+ averaging 31–58 nequiv.∙cm−2∙h−1 after stimulation by 1.0 mM dibutyryl-cAMP. Unstimulated tissues had no net Rb+ transport. The stimulated Rb+ transport was reduced 70% by bilateral replacement of Cl− with gluconate, indicating that Rb+ secretion is dependent on Cl−. Ba2+ (2.0 mM) added to the luminal (mucosal) side had no effect on Rb+ secretion rate, suggesting that apical Ba2+-sensitive K+ channels are not involved. When added on the blood side (serosal), Ba2+ stimulated Rb+ net flux by 68%, possibly as a result of blockade of basal K+ channels and increased intracellular [K+]. Injection of the antiandrogen cyproterone acetate (3 × 0.4 mg∙kg−1 over 7 days in vivo) significantly reduced stimulated Rb+ secretion (in vitro), suggesting that androgens may maintain the active transport characteristics of the blood – testis barrier. The active K+ secretion by the sperm duct accounts for the high concentration of K+ in seminal plasma which in turn is important in maintaining quiescence of developing spermatozoa.

scholarly journals Current Knowledge on Functionality and Potential Therapeutic Uses of Donkey Milk

Animals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1382
Author(s):  
Mina Martini ◽  
Iolanda Altomonte ◽  
Domenico Tricò ◽  
Riccardo Lapenta ◽  
Federica Salari
Keyword(s):  
Animal Models ◽  
Randomized Clinical Trials ◽  
Current Knowledge ◽  
Saturated Fatty Acids ◽  
Cow Milk ◽  
Donkey Milk ◽  
Alpha Linolenic Acid ◽  
High Concentration

The increase of knowledge on the composition of donkey milk has revealed marked similarities to human milk, which led to a growing number of investigations focused on testing the potential effects of donkey milk in vitro and in vivo. This paper examines the scientific evidence regarding the beneficial effects of donkey milk on human health. Most clinical studies report a tolerability of donkey milk in 82.6–98.5% of infants with cow milk protein allergies. The average protein content of donkey milk is about 18 g/L. Caseins, which are main allergenic components of milk, are less represented compared to cow milk (56% of the total protein in donkey vs. 80% in cow milk). Donkey milk is well accepted by children due to its high concentration of lactose (about 60 g/L). Immunomodulatory properties have been reported in one study in humans and in several animal models. Donkey milk also seems to modulate the intestinal microbiota, enhance antioxidant defense mechanisms and detoxifying enzymes activities, reduce hyperglycemia and normalize dyslipidemia. Donkey milk has lower calorie and fat content compared with other milks used in human nutrition (fat ranges from 0.20% to 1.7%) and a more favourable fatty acid profile, being low in saturated fatty acids (3.02 g/L) and high in alpha-linolenic acid (about 7.25 g/100 g of fat). Until now, the beneficial properties of donkey milk have been mostly related to whey proteins, among which β-lactoglobulin is the most represented (6.06 g/L), followed by α-lactalbumin (about 2 g/L) and lysozyme (1.07 g/L). So far, the health functionality of donkey milk has been tested almost exclusively on animal models. Furthermore, in vitro studies have described inhibitory action against bacteria, viruses, and fungi. From the literature review emerges the need for new randomized clinical trials on humans to provide stronger evidence of the potential beneficial health effects of donkey milk, which could lead to new applications as an adjuvant in the treatment of cardiometabolic diseases, malnutrition, and aging.

The centriolar complex isolated from starfish spermatozoa

1981 ◽  
Vol 49 (1) ◽  
pp. 33-49 ◽  
Author(s):  
R. Kuriyama ◽  
H. Kanatani
Keyword(s):  
Gradient Centrifugation ◽  
Sucrose Density Gradient ◽  
Microtubule Assembly ◽  
High Concentration ◽  
Microtubule Organization ◽  
Sucrose Density Gradient Centrifugation ◽  
The Difference ◽  
Distal Centriole

Centrioles from spermatozoa of the starfish, Asterina pectinifera, were isolated and partially purified by solubilization of chromatin followed by sucrose density-gradient centrifugation. The ultrastructure of the isolated centriolar complex was investigated in whole mount preparations by electron microscopy. The complex unit was composed of a pair of centrioles and a pericentriolar structure, which associated with the distal end of the distal centriole by 9 spoke-like satellites extending radially to a marginal ring. Each satellite bifurcated at a dense node forming 2 fan-like shapes with a periodic striated pattern. The tubular structure of the centrioles easily disintegrated, leaving the pericentriolar structure or axonemal microtubules intact. The distal centriole in a spermatozoon served as an initiating site for flagellar microtubule assembly; that is, a number of “9 + 2′ axonemal tubules were observed adhering just beneath the distal end of the basal body. In experiments in vitro, polymerization of microtubule proteins purified from porcine brain was initiated by the structure at the ends of both proximal and distal centrioles, but not from the satellites or the marginal ring. Also, few if any microtubules were formed from the sides of each centriole, even in the presence of a high concentration of exogenous tubulin. On the other hand, centrioles of spermatozoa, when they were in mature ooplasm, could initiate the formation of sperm asters by microtubules. Therefore, centrioles in spermatozoa seem to be able to initiate microtubules in a 2 ways. A possible explanation of the difference between the 2 types of microtubule organization in vivo, i.e. in the sperm cell itself and in the ooplasm, it discussed.

Novel Self-Micro Emulsifying Drug Delivery System for safe intra muscular delivery with improved pharmacodynamics and pharmacokinetics

2021 ◽  
Vol 18 ◽  
Author(s):  
Subheet Kumar Jain ◽  
Neha Panchal ◽  
Amrinder Singh ◽  
Shubham Thakur ◽  
Navid Reza Shahtaghi ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Drug Delivery System ◽  
Delivery System ◽  
Inflammatory Diseases ◽  
Diclofenac Sodium ◽  
Physical Stability ◽  
In Vivo Studies ◽  
High Concentration

Background: Diclofenac sodium (DS) injection is widely used in the management of acute or chronic pain and inflammatory diseases. It incorporates 20 % w/v Transcutol-P as a solubilizer to make the stable injectable formulation. However, the use of Transcutol-P in high concentration leads to adverse effects such as severe nephrotoxicity, etc. Some advancements resulted in the formulation of an aqueous based injectable but that too used benzyl alcohol reported to be toxic for human use. Objective: To develop an injectable self-micro emulsifying drug delivery system (SMEDDS) as a novel carrier of DS for prompt release with better safety and efficacy. Methods: A solubility study was performed with different surfactants and co-surfactants. The conventional stirring method was employed for the formulation of SMEDDS. Detailed in vitro characterization was done for different quality control parameters. In vivo studies were performed using Wistar rats for pharmacokinetic evaluation, toxicological analysis, and analgesic activity. Results: The optimized formulation exhibited good physical stability, ideal globule size (156±0.4 nm), quick release, better therapeutics, and safety, increase in LD50 (221.9 mg/kg) to that of the commercial counterpart (109.9 mg/kg). Further, pre-treatment with optimized formulation reduced the carrageenan-induced rat paw oedema by 88±1.2 % after 4 h, compared to 77±1.6 % inhibition with commercial DS formulation. Moreover, optimized formulation significantly (p<0.05) inhibited the pain sensation in the acetic-acid induced writhing test in mice compared to its commercial equivalent with a better pharmacokinetic profile. Conclusion: The above findings confirmed that liquid SMEDDS could be a successful carrier for the safe and effective delivery of DS

Autocatalytic activities of intron 5 of the cob gene of yeast mitochondria

1988 ◽  
Vol 8 (6) ◽  
pp. 2562-2571
Author(s):  
S Partono ◽  
A S Lewin
Keyword(s):  
Group I Introns ◽  
Yeast Mitochondria ◽  
High Concentration ◽  
Functional Protein ◽  
Full Spectrum ◽  
Group I ◽  
Intron Boundary ◽  
Monovalent Ion

The terminal intron of the mitochondrial cob gene of Saccharomyces cerevisiae can undergo autocatalytic splicing in vitro. Efficient splicing of this intron required a high concentration of monovalent ion (1 M). We found that at a high salt concentration this intron was very active and performed many of the reactions described for other group I introns. The rate of the splicing reaction was dependent on the choice of the monovalent ion; the reaction intermediate, the intron-3' exon molecule, accumulated in NH4Cl but not in KCl. In addition, the intron was more reactive in KCl, accumulating in two different circular forms: one cyclized at the 5' intron boundary and the other at 236 nucleotides from the 5' end. These circular forms were able to undergo the opening and recyclization reactions previously described for the Tetrahymena rRNA intron. Cleavage of the 5' exon-intron boundary by the addition of GTP did not require the 3' terminus of the intron and the downstream exon. An anomalous guanosine addition at the 3' exon and at the middle of the intron was also detected. Hence, this intron, which requires a functional protein to splice in vivo, demonstrated a full spectrum of characteristic reactions in the absence of proteins.

Abstract 6371: Gaseous nitric oxide at high concentration is a powerful anti-tumor agent both in-vitro and in-vivo

2020 ◽  
Author(s):  
Hila Confino ◽  
Steve Lisi ◽  
Rinat Kalaora ◽  
Matan Goldshtein ◽  
Amir Avniel
Keyword(s):  
Nitric Oxide ◽  
High Concentration ◽  
Tumor Agent

Amino acid fluxes in rat thin limb segments of Henle’s loop during in vitro microperfusion

1999 ◽  
Vol 277 (2) ◽  
pp. F204-F210 ◽  
Author(s):  
Olga H. Brokl ◽  
William H. Dantzler
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Apparent Movement ◽  
Transepithelial Transport ◽  
Acid Transport ◽  
Henle's Loop ◽  
Vasa Recta ◽  
The Difference

Amino acids are apparently recycled between loops of Henle and vasa recta in the rat papilla in vivo. To examine more closely papillary amino acid transport, we measured transepithelial fluxes ofl-[14C]alanine and [14C]taurine in thin limbs of Henle’s loops isolated from rat papilla and perfused in vitro. In descending thin limbs (DTL) in vitro, unidirectional bath-to-lumen fluxes tended to exceed unidirectional lumen-to-bath fluxes for both radiolabeled amino acids, although the difference was statistically significant only for taurine. In ascending thin limbs (ATL) in vitro, unidirectional lumen-to-bath fluxes tended to exceed unidirectional bath-to-lumen fluxes, although the difference was again statistically significant only for taurine. These results are compatible with apparent directional movements of amino acids in vivo. However, none of the unidirectional fluxes was saturable or inhibitable, an observation compatible with apparent reabsorption from the ATL in vivo but not compatible with apparent movement from vasa recta to DTL in vivo. There was no evidence of net active transepithelial transport when concentrations of radiolabeled amino acids were matched on both sides of perfused tubule segments. These data suggest that regulation of amino acid movement in vivo may involve the vasa recta, not the DTL of Henle’s loops. The data also suggest that transepithelial movement of amino acids in thin limbs of Henle’s loop may occur via a paracellular route.

In vitro secretion of atrial natriuretic factor: receptor-mediated release of prohormone

1988 ◽  
Vol 254 (5) ◽  
pp. R809-R814 ◽  
Author(s):  
A. T. Veress ◽  
S. Milojevic ◽  
C. Yip ◽  
T. G. Flynn ◽  
H. Sonnenberg
Keyword(s):  
Atrial Natriuretic Factor ◽  
Active Form ◽  
High Concentration ◽  
Natriuretic Factor ◽  
Rat Hearts ◽  
Agonist Concentration ◽  
Atrial Natriuretic Factor Receptor ◽  
Atrial Natriuretic

Secretion of atrial natriuretic factor (ANF) in vivo is thought to be mediated by atrial distension. We have shown previously that nonstretched atria can release natriuretic activity in vitro when stimulated by certain agonists. In the present study atrial appendages from freshly excised rat hearts were incubated at 37 degrees C for up to 1 h in the presence of either vasopressin (5 X 10(-9) mol/l) or angiotensin II (2.5 X 10(-7) mol/l). Aliquots of postincubation media were injected intravenously into anesthetized bioassay rats to determine natriuretic activity. Control media, in which atria had been incubated without agonist, did not cause natriuresis. Significant increases in sodium excretion were seen after injection of media in which atria had been incubated in the presence of either agonist. Injection of medium with the same agonist concentration did not result in comparable natriuresis. Radioimmunoassay (RIA) indicated a high concentration of immunoactive ANF in the natriuretic media. However, radioreceptor assay (RRA) of the same media gave apparent ANF concentrations that were lower by about three orders of magnitude. Because the antibody used in the RIA cross reacts with ANF prohormone, whereas the RRA is sensitive only to the active form, we concluded that agonist-induced, stretch-independent release of ANF is in the form of prohormone, which can be converted to the active hormone in the circulation of the bioassay animal. The conclusion of prohormone release was confirmed by liquid chromatography. The data thus suggest that receptor-mediated as well as stretch-induced ANF secretion may be important in regulating the activity of the ANF system.

Inhibitory Effect Of High Concentration Of Oxygen On LPS-Induced Inflammation In Vivo And In Vitro

2011 ◽  
Author(s):  
MUNEHIRO YAMAGUCHI ◽  
AKIHIKO TANAKA ◽  
SHIN OHTA ◽  
TAKUYA YOKOE ◽  
YOSHITAKA YAMAMOTO ◽  
...  
Keyword(s):  
Inhibitory Effect ◽  
High Concentration

scholarly journals A microfluidic platform for cultivating ovarian cancer spheroids and testing their responses to chemotherapies

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Neda Dadgar ◽  
Alan M. Gonzalez-Suarez ◽  
Pouria Fattahi ◽  
Xiaonan Hou ◽  
John S. Weroha ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
Cancer Cells ◽  
Drug Testing ◽  
Microfluidic Devices ◽  
Needle Aspiration ◽  
High Concentration ◽  
Microfluidic Platform ◽  
Drug Concentrations

Abstract There is increasing interest in utilizing in vitro cultures as patient avatars to develop personalized treatment for cancer. Typical cultures utilize Matrigel-coated plates and media to promote the proliferation of cancer cells as spheroids or tumor explants. However, standard culture conditions operate in large volumes and require a high concentration of cancer cells to initiate this process. Other limitations include variability in the ability to successfully establish a stable line and inconsistency in the dimensions of these microcancers for in vivo drug response measurements. This paper explored the utility of microfluidics in the cultivation of cancer cell spheroids. Six patient-derived xenograft (PDX) tumors of high-grade serous ovarian cancer were used as the source material to demonstrate that viability and epithelial marker expression in the microfluidic cultures was superior to that of Matrigel or large volume 3D cultures. To further demonstrate the potential for miniaturization and multiplexing, we fabricated multichamber microfluidic devices with integrated microvalves to enable serial seeding of several chambers followed by parallel testing of several drug concentrations. These valve-enabled microfluidic devices permitted the formation of spheroids and testing of seven drug concentrations with as few as 100,000 cancer cells per device. Overall, we demonstrate the feasibility of maintaining difficul-to-culture primary cancer cells and testing drugs in a microfluidic device. This microfluidic platform may be ideal for drug testing and personalized therapy when tumor material is limited, such as following the acquisition of biopsy specimens obtained by fine-needle aspiration.

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