scholarly journals Mechanism of Iodide/Chloride Exchange by Pendrin

Endocrinology ◽  
2004 ◽  
Vol 145 (9) ◽  
pp. 4301-4308 ◽  
Author(s):  
Akio Yoshida ◽  
Ichiro Hisatome ◽  
Shinichi Taniguchi ◽  
Norihiro Sasaki ◽  
Yasutaka Yamamoto ◽  
...  
Keyword(s):  
Culture Medium ◽  
Electrophysiological Study ◽  
General Function ◽  
Pendred Syndrome ◽  
High Concentration ◽  
Thyroid Cells ◽  
Chloride Uptake ◽  
Voltage Dependent ◽  
Chloride Exchange ◽  
Exchange Activity

Abstract We performed an electrophysiological study to investigate ion transport of pendrin and thereby understand the pathogenesis of Pendred syndrome. Using pendrin-transfected COS-7 cells, we could show that pendrin transports both iodide and chloride measured as voltage-dependent inward and outward membrane currents. Chloride in the culture medium, [Cl−]o, was efficiently exchanged with cytoplasmic iodide, [I−]i, under physiological concentrations, indicating that pendrin is important for chloride uptake and iodide efflux. Although exchange of iodide in the medium, [I−]o, with cytoplasmic chloride, [Cl−]i, was observed, a significantly high concentration of iodide (10 mm) was required. In addition, either iodide or chloride was required on both sides of the cell membrane for the anion exchange activity of pendrin, indicating that iodide and chloride activate the exchange activity of pendrin while they are transported. The present study further supports that pendrin is responsible for the iodide efflux in thyroid cells where intracellular iodide concentration is high and that the general function of pendrin in other tissues is to transport chloride through exchange with other anions.

Analysis of efficiency of application of media with hyaluronic acid in cryoprotocols

GYNECOLOGY ◽  
2020 ◽  
Vol 22 (2) ◽  
pp. 26-29
Author(s):  
Natalia V. Protopopova ◽  
Elena B. Druzhinina ◽  
Kseniia V. Krylova ◽  
Iuliia V. Mylnikova ◽  
Jan A. Dvoryanov ◽  
...  
Keyword(s):  
Hyaluronic Acid ◽  
Pregnancy Rate ◽  
Embryo Transfer ◽  
Culture Medium ◽  
Genetic Diagnosis ◽  
World Health ◽  
Practical Significance ◽  
Pelvic Surgery ◽  
High Concentration ◽  
Tubal Infertility

According to the World Health Organization, about 2 million new couples experience infertility annually, and their number is growing. An effective way to overcome infertility is assisted reproductive technology (ART). Cryopreservation will rationally solve the issue of preservation and further use of embryos: to delay pregnancy for some time considering womans desire and to prevent ovarian hyperstimulation syndrome. Embryo freezing allows to reduce the rate of repeated ovarian stimulation and perform preimplantation genetic diagnosis. Over the past decades, various cryotransfer options have been proposed to increase ART treatment efficacy, including the use of a culture medium with a high concentration of hyaluronic acid, but there are conflicting data on the use of such a medium in ART programs. Aim. Evaluation of thawed embryo transfers efficacy using the hyaluronic acid-containing culture medium. To achieve the goal, the following tasks were set: to evaluate clinical and medical history data of patients with tubal infertility in cryoprotocols, to analyze the previous cycle of in vitro fertilization and embryological stage, to evaluate the effectiveness of the culture medium with a high content of hyaluronic acid. Materials and methods. A detailed description of the patient sample, inclusion and exclusion criteria, embryological stage, embryo grading, devitrified embryo transfer technique. The article includes 3 tables which present the groups general clinical characteristics, the embryological stage, the rate of pregnancy, depending on the cultivation day. Results. The authors established that in patients with a history of pelvic surgery and sexually transmitted infections, it is advisable to use the culture medium with a high content of hyaluronic acid to transfer the thawed embryo. It was shown that pregnancy rate is 1.5 times higher when transferring devitrified embryos on the 5th day of development with the use of hyaluronic acid-containing culture medium. The conclusion about the pregnancy rate in obese patients is not indisputable, which requires further study. The authors also provide practical recommendations on the use of the culture medium with hyaluronic acid in cryoprotocols. Conclusion. The study allows to optimize the devitrified embryo transfer in patients with tubal infertility using a culture medium with a high content of hyaluronan. This work has undoubted scientific and practical significance.

SHEDDING OF SURFACE PROTEINS BY PORCINE THYROID CELLS

1980 ◽  
Vol 85 (2) ◽  
pp. 245-251 ◽  
Author(s):  
A. BRENNAN ◽  
P. M. POVEY ◽  
B. REES SMITH ◽  
R. HALL
Keyword(s):  
Cell Surface ◽  
Sodium Dodecyl Sulphate ◽  
Culture Medium ◽  
Cell Metabolism ◽  
Sodium Dodecyl ◽  
Surface Proteins ◽  
Half Time ◽  
Thyroid Cells ◽  
Peptide Cleavage ◽  
Membrane Bound

Isolated porcine thyroid cells were surface-labelled with 125I using the lactoperoxidase technique. Samples of the cells were then cultured and harvested at various intervals for up to 7 days. The labelled proteins remaining on the cells or shed into the culture medium were analysed by electrophoresis on polyacrylamide gels run in sodium dodecyl sulphate. These studies indicated that the several different surface proteins of the thyroid cells were lost from the cell surface at similar rates (half-time of approximately 28 h) as the result, at least in part, of a process which depended on active cell metabolism. In addition, the gel profiles obtained from analysis of both medium and membrane-bound labelled proteins were similar and this suggested that peptide cleavage was not involved in the shedding of the majority of these proteins.

Inhibition of proliferative growth in glioma cells by calmodulin antagonists

1986 ◽  
Vol 65 (1) ◽  
pp. 74-79 ◽  
Author(s):  
Nobuyuki Suzuki ◽  
Tetsuo Kanno ◽  
Yutaka Nagata ◽  
Taiji Kato
Keyword(s):  
Culture Medium ◽  
Deoxyribonucleic Acid ◽  
Control Level ◽  
Glioma Cells ◽  
Culture Conditions ◽  
Calmodulin Antagonists ◽  
High Concentration ◽  
Content Type ◽  
Chemically Induced ◽  
Proliferative Growth

✓ The effects of several calmodulin antagonists, such as N-(6-aminohexyl)-5-chloro-1-naphthalene-sulfonamide hydrochloride (W-7) and its dechlorinated structural analogue (W-5), on the growth and proliferation of cultured and transplanted glioma (GA-1, chemically induced from rat glioblasts) were evaluated. Under culture conditions, the concentration of W-7 necessary to exert 50% inhibition of GA-1 glioma cell growth was 50 µM. However, W-5, with a lower binding affinity to calmodulin than W-7, caused no definite inhibition of the proliferation of GA-1 cells in culture. When a low concentration of W-7 (12.5 µM) was added to the culture medium, deoxyribonucleic acid (DNA) synthesis in the GA-1 glioma cells was not markedly affected, whereas both ribonucleic acid (RNA) and protein syntheses were strongly suppressed on incubation for 24 hours. When a high concentration of W-7 (25.0 to 75.0 µM) was applied to the medium, synthesis of DNA, RNA, and protein was distinctly inhibited. When W-7 (50.0 µM) was added to the incubation medium, the calmodulin concentration in the cultured GA-1 was reduced to as much as half the control level within 2 hours, and thereafter remained at this level. Whereas control rats intraperitoneally transplanted with GA-1 cells could survive for 14 to 21 days, daily intraperitoneal injections of W-7 at concentrations of 1.0, 3.0, and 10.0 mg/kg body weight prolonged the survival span to between 21 and 26 days; this corresponded to an increased life span of about 40% compared to the controls.

scholarly journals An axon initial segment is required for temporal precision in action potential encoding by neuronal populations

2018 ◽  
Vol 4 (11) ◽  
pp. eaau8621 ◽  
Author(s):  
Elinor Lazarov ◽  
Melanie Dannemeyer ◽  
Barbara Feulner ◽  
Jörg Enderlein ◽  
Michael J. Gutnick ◽  
...  
Keyword(s):  
Initial Segment ◽  
Axon Initial Segment ◽  
High Concentration ◽  
Information Encoding ◽  
Temporal Precision ◽  
Network Function ◽  
Evolutionary Innovation ◽  
Voltage Dependent ◽  
Vitro Model

Central neurons initiate action potentials (APs) in the axon initial segment (AIS), a compartment characterized by a high concentration of voltage-dependent ion channels and specialized cytoskeletal anchoring proteins arranged in a regular nanoscale pattern. Although the AIS was a key evolutionary innovation in neurons, the functional benefits it confers are not clear. Using a mutation of the AIS cytoskeletal protein βIV-spectrin, we here establish an in vitro model of neurons with a perturbed AIS architecture that retains nanoscale order but loses the ability to maintain a high NaV density. Combining experiments and simulations, we show that a high NaV density in the AIS is not required for axonal AP initiation; it is, however, crucial for a high bandwidth of information encoding and AP timing precision. Our results provide the first experimental demonstration of axonal AP initiation without high axonal channel density and suggest that increasing the bandwidth of the neuronal code and, hence, the computational efficiency of network function, was a major benefit of the evolution of the AIS.

The role of sodium chloride in the process of induction by lithium chloride in cells of the Rana pipiens gastrula

Development ◽  
1968 ◽  
Vol 19 (3) ◽  
pp. 387-396
Author(s):  
Lester G. Barth ◽  
Lucena J. Barth
Keyword(s):  
Sodium Chloride ◽  
Culture Medium ◽  
Rana Pipiens ◽  
Divalent Cations ◽  
Pigment Cells ◽  
Distilled Water ◽  
Sodium Ions ◽  
Monovalent Cations ◽  
High Concentration

A study of the effects of a series of monovalent cations, Li+, Na+ and K+, and a series of divalent cations, Mn2+, Ca2+ and Mg2+, upon small aggregates of cells taken from the presumptive epidermis of Rana pipiens gastrulae revealed that these ions induce nerve and pigment cells (Barth, 1965). The effectiveness of both series of ions as inductors was similar to their effects on decreasing the electrophoretic mobility of DNA as determined by Ross & Scruggs (1964). When it was found that sucrose in glass-distilled water also would induce nerve and pigment cells the role of ions as inductors came under closer scrutiny. A study of the nature of the induction by sucrose revealed that a relatively high concentration of sodium ions was necessary in the culture medium used after sucrose treatment (Barth, 1966).

Role of calcium and calmodulin in release of kallikrein and tonin from rat submandibular gland

1986 ◽  
Vol 250 (3) ◽  
pp. C480-C485 ◽  
Author(s):  
S. R. Maitra ◽  
O. A. Carretero ◽  
S. W. Smith ◽  
S. F. Rabito
Keyword(s):  
Submandibular Gland ◽  
Incubation Medium ◽  
High Concentration ◽  
Calcium Blockers ◽  
Control Value ◽  
Voltage Dependent ◽  
Voltage Dependent Calcium Channels ◽  
Intracellular Mediators

We investigated the role of calcium and calmodulin as intracellular mediators of kallikrein and tonin release induced by norepinephrine (NE). We studied the secretion rate of kallikrein and tonin from submandibular gland of rat in response to NE in the presence or absence of calcium, two calcium blockers, and four different calmodulin antagonists. Submandibular gland slices were incubated in vitro, and glandular kallikrein and tonin secreted into the incubation medium were determined by direct radioimmunoassays and expressed as nanograms per minute per milligram tissue. NE (10(-5) and 10(-4) M) increased the kallikrein secretion from the control value of 8.2 +/- 2.6 to 134.9 +/- 41.4 (P less than 0.05) and to 191.2 +/- 62.7 (P less than 0.05), and the release of tonin from a basal rate of 3.5 +/- 0.6 to 51.5 +/- 9.1 (P less than 0.05) and to 64.4 +/- 13.7 (P less than 0.05). The deletion of calcium and addition of EGTA into the incubation medium significantly attenuated the secretion of kallikrein and tonin induced by NE. Nifedipine, at concentrations which inhibit voltage-dependent calcium channels, did not affect the release of kallikrein and tonin, and only a high concentration (10(-4) M) reduced the release. TMB-8, a blocker of intracellular calcium, had no effect either. Phenothiazines, triflupromazine (10(-6) M) and trifluoperazine (10(-4) M), decreased significantly the kallikrein release elicited by 10(-5) M NE.(ABSTRACT TRUNCATED AT 250 WORDS)

Altered L-type Ca2+ channel currents in vascular smooth muscle cells from experimental diabetic rats

2000 ◽  
Vol 278 (3) ◽  
pp. H714-H722 ◽  
Author(s):  
Rui Wang ◽  
Yuejin Wu ◽  
Guanghua Tang ◽  
Lingyun Wu ◽  
Salma Toma Hanna
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Vascular Complications ◽  
Muscle Cells ◽  
Inhibitory Effect ◽  
Diabetic Rats ◽  
High Concentration ◽  
Voltage Dependent

Vascular complications of diabetes are associated with abnormal Ca2+ handling by vascular smooth muscle cells (SMCs) in which the alteration in L-type voltage-dependent Ca2+ channel (VDCC) currents may play an important role. In the present study, the characteristics of L-type VDCC currents in tail artery SMCs from streptozotocin-induced diabetic rats were examined. The densities, but not the voltage dependence, of L-type VDCC currents were reduced as diabetes progressed from 1 wk to 3 mo. The inhibitory effect of dibutyryl-cAMP on L-type VDCC currents was greater in diabetic SMCs than in age-matched control cells ( P < 0.01). Both the stimulatory effect of BAY K 8644 and the inhibitory effect of nifedipine on L-type VDCC currents were significantly enhanced in diabetic cells. The diabetes-related abnormalities in L-type VDCC currents were mimicked by culturing SMCs with a high concentration of glucose. Our results suggest that the properties of L-type VDCC in diabetic vascular SMCs were significantly altered, partially related to the increased L-type VDCC sensitivity to cAMP and hyperglycemia.

Effect of P1-purinergic agonist on thyrotropin stimulation of H2O2 generation in FRTL-5 and porcine thyroid cells

1994 ◽  
Vol 130 (2) ◽  
pp. 180-186 ◽  
Author(s):  
Ulla Björkman ◽  
Ragnar Ekholm
Keyword(s):  
Adenylate Cyclase ◽  
Primary Culture ◽  
Purinergic Receptor ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Camp Accumulation ◽  
High Concentration ◽  
Thyroid Cells ◽  
H2o2 Generation ◽  
Stimulation Of

Björkman U, Ekholm R. Effect of P1-purinergic agonist on thyrotropin stimulation of H2O2 generation in FRTL-5 and porcine thyroid cells. Eur J Endocrinol 1994;130:180–6. ISSN 0804–4643 Our previous studies have shown that the generation of H2O2 in FRTL-5 thyroid cells is regulated via both the adenylate cyclase/cyclic adenosine monophosphate (cAMP) and Ca2+/phosphatidylinositol pathway: thyrotropin (TSH) stimulates H2O2 generation through both pathways, via the former at a low concentration and via the latter at a high concentration. In porcine thyrocytes in primary culture H2O2 generation is stimulated only via the Ca2+/phosphatidylinositol route. In the present study we explored the effect of a P1-purinergic agonist (phenylisopropyladenosine, PIA) on stimulations induced by TSH and by adenosine triphosphate (ATP), an activator of the Ca2+/phosphatidylinositol cascade via the P2-purinergic receptor. In FRTL- 5 cells, PIA potentiated H2O2 generation stimulated by TSH at 10U/l (but not at 1 U/l), Ca2+ mobilization induced by TSH and Ca2+ mobilization induced by ATP at 1 μmol/l (but not 10 μmol/l). Phenylisopropyladenosine strongly inhibited TSH-induced cAMP accumulation in FRTL-5 cells. In pig thyrocytes, PIA had no effect on H2O2 generation stimulated by TSH or ATP and no effect on ATP-stimulated Ca2+ mobilization. Also, PIA did not inhibit TSH-stimulated cAMP accumulation in pig thyrocytes, and by itselfhad no effecton H2O2 generation or Ca2 + mobilization. Thus, in FRTL-5 cells, but not in porcine thyrocytes, PIA modulates TSH-stimulated H2O2 generation by enhancing the Ca2+/phosphatitylinositol route and inhibiting the adenylate cyclase/cAMP route of the TSH signal. The net result of this modulation apparently depends on the balance between inhibition of the cAMP route and enhancement of the Ca2+ route. This may explain the lack of potentiation observed by 1 U/1 TSH. Ragnar Ekholm, Department of Anatomy, Medicinaregatan 3, S-413 90 Göteborg, Sweden

Triiodothyronine and 3′,5′-cyclic AMP secretion by cultured human thyroid cells in response to thyrotropin and thyroid-stimulating immunoglobulin

1988 ◽  
Vol 119 (4) ◽  
pp. 493-500 ◽  
Author(s):  
Z. Kraiem ◽  
O. Sadeh ◽  
E. Sobel
Keyword(s):  
De Novo ◽  
Testicular Tissue ◽  
Culture Conditions ◽  
Human Thyroid ◽  
Intracellular Camp ◽  
Camp Accumulation ◽  
High Concentration ◽  
Thyroid Cells ◽  
Concomitant Reduction ◽  
Dual Action

Abstract. We have established a relatively simple and sensitive system for measuring T3 as well as cAMP secretion using cryopreserved human thyroid cells in culture. We defined optimal culture conditions and characterized the system. T3 secretion from human thyrocytes (only 1 × 105 cells/well) could be stimulated in a time- and dose-dependent fashion by both TSH (doses as low as 10 mU/l) and thyroid-stimulating immunoglobulin to levels 5- to 10-fold above baseline. The response to the thyroid stimulating agents was preserved for at least 3 weeks. Experiments with inhibitors of iodothyronine synthesis (propylthiouracil and methimazole) indicated that the bulk of the TSH-stimulated T3 secretion measured apparently derives from de novo iodothyronine biosynthesis rather than preformed T3. We utilized the system to investigate some aspects in the regulation of human thyrocyte T3 and cAMP secretion. Maximum stimulation of the thyroid hormone was achieved at TSH doses capable of evoking a further rise in levels of cAMP. A rise in cAMP accumulation was observed as early as 15 min following exposure to TSH, whereas it took 1–4 days to detect a significant increase in T3 secretion. Within 6 h of incubation, the bulk of TSH-stimulated intracellular cAMP was found released into the medium. l-methyl-3-isobutylxanthine (MIX) caused a dose-related decrease (beyond 0.1 mmol/l MIX) in TSH-stimulated T3 secretion which contrasted with a concomitant expected increase in cAMP accumulation. Hence, as also observed in adrenal and testicular tissue, xanthines at high concentration seem to exhibit a dual action: potentiation of cAMP accumulation by inhibiting phosphodiesterase activity and a concomitant reduction of hormone formation.

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