Vitamin D2at high and low concentrations exert opposing effects on molecular order and dynamics of dipalmitoyl phosphatidylcholine membranes

Fourier Transform Infrared spectroscopic studies show that low concentrations of vitamin D2(1 and 3 mol %) does not induce significant change in the overall shape of the thermotropic profile of dipalmitoyl phosphatidylcholine (DPPC) membrane. In contrast, at higher concentrations of vitamin D2(9 and 12 mol %), the phase transition shifts to lower temperatures and a significant broadening in the phase transition curve is also observed. Low concentration of vitamin D2decreases the frequency of the CH2stretching mode, implying an ordering effect, whilst high concentration of vitamin D2disorders the system. Furthermore, at low and high concentrations, vitamin D2causes opposing effect on membrane dynamics. It decreases the bandwidth of the CH2stretching modes at low concentrations while increasing it at high concentrations. We have also observed different actions of vitamin D2at low and high concentrations in the deep interior and interfacial region of the membrane, by monitoring the frequency of the CH3stretching band and C=O stretching bands, respectively.

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Infrared Spectroscopic Studies on the Dipalmitoyl Phosphatidylcholine Bilayer Interactions with Calcium Phosphate: Effect of Vitamin D2

Spectroscopy An International Journal ◽

10.1155/2002/381692 ◽

2002 ◽

Vol 16 (3-4) ◽

pp. 399-408 ◽

Cited By ~ 14

Author(s):

Neslihan Toyran ◽

Feride Severcan

Keyword(s):

Vitamin D ◽

Calcium Phosphate ◽

Liquid Crystalline ◽

Spectroscopic Studies ◽

The Body ◽

Head Group ◽

Dipalmitoyl Phosphatidylcholine ◽

Major Structural Component ◽

Ftir Spectral Analysis ◽

Acyl Chains

In the present work, the interaction of calcium-phosphate with DPPC (dipalmitoyl phosphatidylcholine) model membranes has been studied in the presence and absence of vitamin D2by using Fourier Transform Infrared (FTIR) spectroscopy. Calcium and phosphorus are the most abundant elements in the body. They combine in the form of calcium phosphate salt, called hydroxyapatite. Hydroxyapatite is the major structural component of the bone. Calcium phosphate assists with the digestion and absorption of food and is vitally important for the building of sturdy bone and body structures and a robust constitution. Phosphorus is extracted from foods and its use is controlled by vitamin D and calcium. FTIR spectral analysis results suggested that, calcium–phosphate complex, which is the major component of the bones, decreases the phase transition temperature to lower values, causes a loss in cooperativity of the acyl chains, decreases the order of the membrane in both phases and decreases the dynamics of the membrane in the liquid crystalline phase, increases the flexibility of the chains in the center of the bilayer in both phases, and increases the mobility of the head group of DPPC in the gel phase. The effect of calcium-phosphate on DPPC liposomes diminishes with the addition of vitamin D2into the liposomes. Our results suggest how calcium-phosphate and/or vitamin D2, which have indispensable role for the functioning of the bone tissue, affect the thermal behaviour of DPPC liposomes at molecular level.

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Vascular responses to compound 48/80 in rat mesenteric vascular beds

Canadian Journal of Physiology and Pharmacology ◽

10.1139/cjpp-2015-0442 ◽

2016 ◽

Vol 94 (6) ◽

pp. 620-626 ◽

Cited By ~ 1

Author(s):

Honghua Jin ◽

Zhen Li ◽

Shingo Takatori ◽

Toshihiro Koyama ◽

Xin Jin ◽

...

Keyword(s):

Mast Cells ◽

Ruthenium Red ◽

High Concentration ◽

Phase 3 ◽

Vascular Effect ◽

Vascular Responses ◽

Endogenous Histamine ◽

Low Concentrations ◽

Vascular Beds ◽

High Concentrations

A further investigation was performed on the vascular effect of endogenous histamine using the histamine releaser, compound 48/80, in rat mesenteric vascular beds with active tone. In preparations with intact endothelium, low concentrations of compound 48/80 (1.53 × 10−5 – 3 × 1.53 × 10−5 mg/mL) perfusion for 1 min only induced a small vasodilation. High concentrations of compound 48/80 (1.53 × 10−4 – 3 × 1.53 × 10−2 mg/mL) induced a biphasic vascular responses, an initial vasoconstriction followed a subsequent long-lasting vasodilation. The vasodilation induced by low concentrations of compound 48/80 and the vasoconstriction induced by high concentration of compound 48/80 was inhibited by olopatadine. However, cimetidine did not affect the responses induced by compound 48/80. Endothelium removal enlarged the compound 48/80-induced phase-2 vasoconstriction, while it attenuated the phase-3 vasodilation. Additionally, indomethacin and seratrodast significantly inhibited vasoconstriction but it did not affect the long-lasting vasodilation induced by high concentrations of compound 48/80. Ruthenium red inhibited the vasodilation induced by low concentrations and high concentrations of compound 48/80. These results suggest that the vasoconstriction induce by high concentrations of compound 48/80 is mediated by endogenous histamine released from mast cells. It is also suggested that thromboxane A2 released from mast cells is related to the vasoconstriction.

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Biphasic Effect of Pirfenidone on Angiogenesis

Frontiers in Pharmacology ◽

10.3389/fphar.2021.804327 ◽

2022 ◽

Vol 12 ◽

Author(s):

Donghao Gan ◽

Wenxiang Cheng ◽

Liqing Ke ◽

Antonia RuJia Sun ◽

Qingyun Jia ◽

...

Keyword(s):

Vascular Endothelial Cells ◽

Tube Formation ◽

Endothelial Cell Migration ◽

High Concentration ◽

Low Concentrations ◽

Biphasic Effect ◽

High Concentrations ◽

And Migration ◽

The Impact

Pirfenidone (PFD), a synthetic arsenic compound, has been found to inhibit angiogenesis at high concentrations. However, the biphasic effects of different PFD concentrations on angiogenesis have not yet been elucidated, and the present study used an in vitro model to explore the mechanisms underlying this biphasic response. The effect of PFD on the initial angiogenesis of vascular endothelial cells was investigated through a Matrigel tube formation assay, and the impact of PFD on endothelial cell migration was evaluated through scratch and transwell migration experiments. Moreover, the expression of key migration cytokines, matrix metalloproteinase (MMP)-2 and MMP-9, was examined. Finally, the biphasic mechanism of PFD on angiogenesis was explored through cell signaling and apoptosis analyses. The results showed that 10–100 μM PFD has a significant and dose-dependent inhibitory effect on tube formation and migration, while 10 nM–1 μM PFD significantly promoted tube formation and migration, with 100 nM PFD having the strongest effect. Additionally, we found that a high concentration of PFD could significantly inhibit MMP-2 and MMP-9 expression, while low concentrations of PFD significantly promoted their expression. Finally, we found that high concentrations of PFD inhibited EA.hy926 cell tube formation by promoting apoptosis, while low concentrations of PFD promoted tube formation by increasing MMP-2 and MMP-9 protein expression predominantly via the EGFR/p-p38 pathway. Overall, PFD elicits a biphasic effect on angiogenesis through different mechanisms, could be used as a new potential drug for the treatment of vascular diseases.

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Suppression of Canola (Brassica napus) Resistance by Virulent Isolates of Plasmodiophora brassicae (Clubroot) During Primary Infection

Plant Disease ◽

10.1094/pdis-03-19-0659-re ◽

2020 ◽

Vol 104 (2) ◽

pp. 430-437

Author(s):

Junye Jiang ◽

Rudolph Fredua-Agyeman ◽

Stephen E. Strelkov ◽

Sheau-Fang Hwang

Keyword(s):

Brassica Napus ◽

Plasmodiophora Brassicae ◽

Negative Control ◽

Pcr Analysis ◽

High Concentration ◽

Clubroot Disease ◽

Low Concentrations ◽

High Concentrations ◽

Experimental Treatments ◽

Positive Controls

The planting of clubroot resistant (CR) canola (Brassica napus) is the most effective method to manage clubroot. Since 2013, many Plasmodiophora brassicae isolates capable of overcoming resistance have been detected, often in mixtures with avirulent isolates. To improve understanding of the effect of low concentrations of virulent isolates on host resistance, three CR canola cultivars (45H29, L135C, and L241C) were inoculated with pairs of isolates representing virulent/avirulent pathotypes (2*/2, 3*/3, and 5*/5) collected after or before the introduction of CR canola, respectively. Seven-day-old seedlings of each cultivar were incubated for 2 days in low concentrations (1 × 103 spores/ml) of the virulent isolates, followed by a second inoculation with a high concentration (1 × 107 spores/ml) of the avirulent isolates. Positive controls comprised seedlings inoculated with low concentrations of the virulent isolates followed by high concentrations of the virulent isolates (PC1) or only with high concentrations of virulent isolates (PC2). Negative controls comprised seedlings inoculated only with high concentrations of the avirulent isolates (NC1) or only with low concentrations of the virulent isolates (NC2). Clubroot severity was significantly higher in all nine experimental treatments (low virulent plus high avirulent) than in the negative control NC1 (high avirulent) but was lower in the experimental treatments than in the positive controls (PC1 and PC2). Low concentrations of virulent isolates alone (NC2) caused moderate clubroot. Disease severity correlated well with P. brassicae biomass in canola as determined by quantitative PCR analysis 28 to 35 days after inoculation. This study revealed that low concentrations of virulent isolates compromised canola resistance for infection by avirulent isolates.

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Assay-Specific Decision Limits for Two New Automated Parathyroid Hormone and 25-Hydroxyvitamin D Assays

Clinical Chemistry ◽

10.1373/clinchem.2004.037606 ◽

2005 ◽

Vol 51 (2) ◽

pp. 395-400 ◽

Cited By ~ 37

Author(s):

Jean-Claude Souberbielle ◽

Véronique Fayol ◽

Corinne Sault ◽

Ethel Lawson-Body ◽

André Kahan ◽

...

Keyword(s):

Vitamin D ◽

Regression Analysis ◽

Parathyroid Hormone ◽

Primary Hyperparathyroidism ◽

Healthy Individuals ◽

Hydroxyvitamin D ◽

Low Concentrations ◽

25 Hydroxyvitamin D ◽

High Concentrations ◽

Serum Pth

Abstract Background: The recent development of nonradioactive automated assays for serum parathyroid hormone (PTH) and 25-hydroxyvitamin D (25OHD) has made measurement of these two hormones possible in many laboratories. In this study, we compared two new assays for PTH and 25OHD adapted on an automated analyzer, the LIAISON®, with two manual immunoassays used worldwide. Methods: We studied 228 osteoporotic patients, 927 healthy individuals, 38 patients with primary hyperparathyroidism, and 167 hemodialyzed patients. Serum PTH was measured with the Allegro® and the LIAISON assays, and 25OHD was measured with DiaSorin RIA and the LIAISON assay. Regression analysis was used to calculate decision thresholds for the LIAISON assays that were equivalent to those of the Allegro PTH and DiaSorin 25OHD assays. Results: The 25OHD concentrations obtained with the LIAISON assay and the RIA in osteoporotic patients were well correlated (r = 0.83; P <0.001). Regression and Bland–Altman analyses suggested that the LIAISON 25OHD assay reads lower than the DiaSorin RIA at low concentrations but higher at high concentrations. However, the cutoff (50 nmol/L) used in our laboratories to define vitamin D insufficiency with the DiaSorin RIA is applicable to the LIAISON 25OHD assay. In 927 healthy individuals, the 3rd–97th percentile intervals were 3–80 ng/L and 13–151 nmol/L for the LIAISON PTH and 25OHD concentrations, respectively. However, 506 individuals (54.6%) were vitamin D-insufficient; we therefore considered only the 421 individuals with a LIAISON 25OHD >50 nmol/L as eligible for the reference population for the LIAISON PTH assay. In this group, the 3rd–97th percentile interval for LIAISON PTH was 3–51 ng/L. Considering upper reference limits of 46 and 51 ng/L for the Allegro and LIAISON assays, respectively, the frequency of above-normal PTH concentrations in patients with primary hyperparathyroidism was similar in both assays. Regression analysis between serum PTH measured by the Allegro and LIAISON assays in 167 hemodialyzed patients and the corresponding Bland–Altman analysis of these data suggest that the LIAISON PTH assay tends to read higher than the Allegro assay at low concentrations but lower at high concentrations (>300 ng/L). Conclusions: Because clinical decision limits for both PTH and 25OHD should be assay specific, we propose equivalences between these assays and two manual assays used worldwide. These assay-specific decision limits should help potential users of the LIAISON PTH and 25OHD assays.

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Genistein Inhibits Cell Proliferation and Induces Mitochondrial and Nuclear Alterations That Indicate Mechanisms Involved in Apoptosis

Microscopy and Microanalysis ◽

10.1017/s1431927600036746 ◽

2000 ◽

Vol 6 (S2) ◽

pp. 850-851

Author(s):

Geoffrey Gobert ◽

Ed Curren ◽

Wade Welshons ◽

Qing-yuan Sun ◽

Heide Schatten

Keyword(s):

Breast Cancer ◽

Cell Proliferation ◽

Tyrosine Kinases ◽

High Concentration ◽

Transmission Electron ◽

Low Concentrations ◽

Culture Models ◽

High Concentrations ◽

Underlying Mechanisms ◽

Nuclear Alterations

A highly significant correlation between reduced incidence of breast cancer in Asian countries and consumption of soy suggests that specific components in soy may have anticarcinogen activity. The soy ingredients genistein and daidzein have been found to inhibit induced breast tumors in animal and cell culture models. These isoflavones are known to be both agonists and antagonists of estrogen activity but only genistein is also a potent inhibitor of tyrosine kinases which are the primary intracellular signalling mechanisms associated with the regulation of cell proliferation.Genistein promotes cell proliferation in breast cancer cells at low concentrations in its function as estrogen agonist but inhibits cell proliferation at high concentrations (30 μM). In order to investigate the underlying mechanisms by which high concentration of genistein inhibit cell proliferation we treated MCF-7 cells with increasing concentrations of genistein and analyzed cells by immunofluorescence and transmission electron microscopy (TEM).

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Concentration dependent different action of progesterone on the order, dynamics and hydration states of the head group of dipalmitoyl-phosphatidylcholine membrane

Spectroscopy An International Journal ◽

10.1155/2005/641043 ◽

2005 ◽

Vol 19 (4) ◽

pp. 213-219 ◽

Cited By ~ 4

Author(s):

Filiz Korkmaz ◽

Halil Kirbiyik ◽

Feride Severcan

Keyword(s):

Liquid Crystalline ◽

Membrane Dynamics ◽

Head Group ◽

Interfacial Region ◽

Progesterone Concentration ◽

Dramatic Decrease ◽

Physiological Level ◽

Dipalmitoyl Phosphatidylcholine ◽

Multilamellar Liposomes ◽

Linear Plot

Interactions of progesterone with zwitterionic dipalmitoyl phosphatidylcholine (DPPC) multilamellar liposomes (MLVs) were investigated as a function of progesterone concentration at selected temperatures monitoring both the gel and liquid crystalline phase, by using Fourier Transform Infrared spectroscopy (FTIR). It has been show that the effect of progesterone on membrane dynamics is dependent on progesterone concentration. At 1 mol%, which is close to physiological level, progesterone behaves differently. At this concentration the decrease in dynamics is more noticeable. Additionally a dramatic decrease in the strength of hydrogen bonding in the interfacial region of the bilayer is also observed. When concentration increases up to 12 mol% opposite behaviour is observed at all interactions. Above 12 mol%, progesterone–DPPC interactions shows almost linear plot.

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Heavy metals uptake by hyperaccumulating flora in some serpentine soils of Kosovo

Global NEST Journal ◽

10.30955/gnj.001804 ◽

2016 ◽

Vol 18 (1) ◽

pp. 214-222 ◽

Cited By ~ 5

Keyword(s):

Heavy Metals ◽

Ultramafic Rocks ◽

Metamorphic Rocks ◽

Serpentine Soils ◽

High Concentration ◽

Important Indicator ◽

Low Concentrations ◽

Close Relationship ◽

High Concentrations ◽

Heavy Metals Uptake

Ultramafics represent magmatic or metamorphic rocks which are characterized by high concentrations of Mg, Fe, Ni, Cr and Co and low concentrations of Ca, and K. Serpentine soils are weathered products of a range of ultramafic rocks composed of ferromagnesian silicates. The aim of this study was to determine the content of heavy metals in some of serpentine soils of Kosovo and heavy metals uptake by entire associated flora. Furthermore, another objective of this study was finding out bioavailable Ca/Mg relationship, which is very important indicator for plants’ development. The sampling was conducted in June 2014. A total of three serpentine areas have been surveyed and 7 soil samples have been taken in various depths of soil profiles. Those samples were analyzed for total Ca, Cd, Co, Cr, Cu, Mn, Ni, Pb, Fe and Zn. Results showed that each site exhibited a high concentration of at least one metal. The maximum concentrations of metals in soils Dry Matter (DM) were 108.9 mg kg-1 Cd, 95.8 mg kg-1 Co, 1206 mg kg-1 Cr, 24 mg kg-1 Cu, 2570 mg kg-1 Ni, 21.7 mg kg-1 Pb, 39 mg kg-1 Zn, and 51563 mg kg- Fe. The serpentine soils at all sites were characterized by elevated levels of heavy metals, which showed typical properties of ultramafic environments. Nickel Total at studied areas varied between 1543 and 2570 mg kg-1, while the highest Ni concentration was found in aerial part of Alyssum markgrafii (4038 mgkg-1), <div> Based on our findings on the field we concluded that there is a close relationship between the quantity of Ni in soil and Ni uptake in plants. </div>

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Artefactual 25-OH vitamin D concentration in multiple myeloma

Annals of Clinical Biochemistry International Journal of Laboratory Medicine ◽

10.1177/0004563217690175 ◽

2017 ◽

Vol 54 (6) ◽

pp. 716-720 ◽

Cited By ~ 1

Author(s):

Michal WS Ong ◽

Rashim Salota ◽

Tracy Reeman ◽

Marta Lapsley ◽

Lydia Jones

Keyword(s):

Rheumatoid Arthritis ◽

Vitamin D ◽

Rheumatoid Factor ◽

Reference Method ◽

Sun Exposure ◽

High Concentration ◽

History Of ◽

High Concentrations ◽

Vitamin D Supplements ◽

25 Oh Vitamin D

The most commonly used techniques to measure vitamin D are automated immunoassays which are known to be affected by interferences, especially from immunoglobulins present in the patient’s serum. We present a case of a patient with myeloma in whom interference with the vitamin D assay was identified. An 83-year-old female, known to have IgG myeloma, was found to have a high concentration of 25-OH vitamin D on a routine test without any signs of vitamin D toxicity. She was not taking vitamin D supplements or any other multivitamin preparation and had minimal sun exposure. The initial and subsequent samples run by the ARCHITECT 25-OH vitamin D assay (chemiluminescent microparticle immunoassay technology, Abbott Laboratories, Abbott Park, IL) showed a high concentration of 25-OH vitamin D of 281 nmol/L and 327 nmol/L, respectively. Further fresh samples taken for 25-OH vitamin D and analysed by liquid chromatography-mass spectrometry (LC-MS/MS) and ARCHITECT analysis showed results of 49 nmol/L and 289 nmol/L, respectively. Our patient had high concentrations of circulating IgG paraproteins and had a long history of rheumatoid arthritis; paraproteins and rheumatoid factor may interfere in the assay. In conclusion, we report a case of a patient with IgG myeloma and rheumatoid arthritis with high concentrations of 25-OH vitamin D detected by the Abbott ARCHITECT, but not by a reference method (LC-MS/MS). The most likely cause of the discordant results is interference in the immunoassay by the paraprotein but interference from rheumatoid factor remains a possibility.

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Receptors involved in helodermin action on rat pancreatic acini

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.1986.251.5.g602 ◽

1986 ◽

Vol 251 (5) ◽

pp. G602-G610 ◽

Cited By ~ 1

Author(s):

J. P. Dehaye ◽

J. Winand ◽

C. Damien ◽

F. Gomez ◽

P. Poloczek ◽

...

Keyword(s):

Protein Phosphorylation ◽

Amylase Secretion ◽

High Concentration ◽

Amylase Release ◽

Pancreatic Acini ◽

Heloderma Suspectum ◽

Low Concentrations ◽

High Concentrations ◽

Camp Levels ◽

Camp Elevation

Helodermin is a new peptide isolated from the venom of Heloderma suspectum. Its effects on rat pancreatic acini were compared with those of secretin and vasoactive intestinal peptide (VIP). Four classes of receptors with decreasing affinity for secretin (S1, S2, S3, and S4) were first delineated. Occupancy of S1 and S2 by secretin was responsible for a biphasic adenosine 3',5'-cyclic monophosphate (cAMP) response. S3 was VIP preferring so that the VIP-induced increase in cAMP could be inhibited by VIP-(10 --28). S2 and S3 allowed cAMP elevation, protein phosphorylation, weak secretory effects, and potentiation of cholecystokinin octapeptide (CCK-8) when occupied by secretin and VIP, respectively. A more efficient exocytosis was observed with secretin interacting with low-affinity receptors S4. Helodermin increased cAMP levels 14-fold, this increase being inhibited by VIP-(10–28). Low concentrations of helodermin stimulated amylase secretion twofold and potentiated secretion by CCK-8. High concentrations of helodermin stimulated secretion another 2.6-fold. Helodermin bound to the four secretin receptors with a weak selectivity. At low concentration, helodermin stimulated cAMP elevation, protein phosphorylation, amylase release, and potentiation of CCK-8 through S3, whereas at high concentration it stimulated secretion via S4.

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