scholarly journals Binding of zinc and calcium to inositol phosphates (phytate) in vitro

1990 ◽  
Vol 64 (1) ◽  
pp. 225-232 ◽  
Author(s):  
C. J. Simpson ◽  
A. Wise
Keyword(s):  
Inositol Phosphates ◽  
Lower Proportion ◽  
The Other ◽  
Binding Affinities ◽  
Inositol Hexaphosphate ◽  
Neutral Ph ◽  
Hydrolysis Of ◽  
Phosphate Groups

Inositol compounds with three to five phosphate groups (IP3–IP5) were produced by hydrolysis of phytate (inositol hexaphosphate, IP6) and their binding affinities for calcium and zinc investigated at neutral pH with relative concentrations that had been found in a range of students' meals. Zn solubility was negligible at many of these concentrations, with less Zn bound to precipitates of Ca-IP6 than Ca-IP5. The capacity to precipitate Zn at these ratios fell between IP5 and IP3. Zn was partially desorbed by soluble chelators (histidine and picolinate), especially when it had been adsorbed to preformed Ca-IP precipitates. A lower proportion of Zn was accessible to soluble chelators from Ca-IP4 than the other compounds. IP3-IP4 were hydrolysed. by phytase more readily than IP5–IP6.

scholarly journals Uptake and Metabolism of Tritiated 17ß-Oestradiol and Oestrone by Rabbit Uterine Tissue in vitro

1974 ◽  
Vol 27 (2) ◽  
pp. 137 ◽  
Author(s):  
RG Gabb ◽  
GM Stone
Keyword(s):  
Nuclear Receptor ◽  
Mode Of Action ◽  
Nuclear Extract ◽  
Lower Proportion ◽  
The Other ◽  
Uterine Tissue ◽  
Uptake And Metabolism

To determine whether the established capability of rabbit uterine tissue to interconvert 17 p-oestradiol and oestrone might have some effect on the mode of action of the oestrogens in this organ, the in vitro interconversion of [3H]-17p-oestradiol and [3H]oestrone by rabbit endometrial and myometrial tissue was investigated and the identity of radiometabolites in 'soluble, 'mitochondrial-microsomal' a'nd 'nuclear' preparations was studied. Both endometrial and myometrial tissue were found to be capable of oxidoreduction of the oestrogens, the equilibrium of the reaction favouring the reduction of oestrone. Irrespective of the tissue--steroid combination studied, the greater part of the radioactivity in all fractions was associated with 17p-oestradiol. The relative proportions of [3Hl-17p-oestradiol and [3H]oestrone varied between fractions, the nuclear preparation consistently showing a lower proportion of oestrone than the other fractions. Sephade<c fractionation of a 0'4M KCl 'nuclear extract' revealed that proportionately less oestrone than 17p-oestradiol was bound to the nuclear 'receptor'. These findings provide further evidence for 17p-oestradiol being the ovarian oestrogen which is active in the uterus, and suggest a role for uterine oxidoreduction of oestrogens in the control exercised over this organ by these steroids.

scholarly journals Affinities of β-Lactams for Penicillin Binding Proteins of Chlamydia trachomatis and Their Antichlamydial Activities

2001 ◽  
Vol 45 (1) ◽  
pp. 303-305 ◽  
Author(s):  
Christopher Storey ◽  
Ian Chopra
Keyword(s):  
Chlamydia Trachomatis ◽  
Binding Proteins ◽  
Inhibitory Concentration ◽  
Minimum Bactericidal Concentration ◽  
The Other ◽  
Binding Affinities ◽  
Penicillin Binding Proteins

ABSTRACT Binding affinities of β-lactam antibiotics for the three penicillin binding proteins (PBPs) from Chlamydia trachomatis were determined in vitro and compared with their antichlamydial activities. Mecillinam selectively inhibited PBP1, with a 50% inhibitory concentration for PBP1 binding (0.2 μg/ml) similar to the MIC (0.1 μg/ml) and minimum bactericidal concentration (0.25 μg/ml). Although the other β-lactams inhibited a wider range of PBPs than mecillinam, their antichlamydial activities were inferior to that of mecillinam.

scholarly journals Quercetin influences in vitro maturation, apoptosis and metabolically active mitochondria of goat oocytes

Zygote ◽  
2018 ◽  
Vol 26 (6) ◽  
pp. 465-470 ◽  
Author(s):  
A.A.A. Silva ◽  
M.N.P. Silva ◽  
L.B.F. Figueiredo ◽  
J.D. Gonçalves ◽  
M.J.S. Silva ◽  
...  
Keyword(s):  
In Vitro Maturation ◽  
Cumulus Cells ◽  
Lower Proportion ◽  
The Other ◽  
Mitochondrial Activity ◽  
Base Medium

SummaryThe present study aimed to investigate the effect of quercetin as an alternative antioxidant to cysteamine on in vitro maturation. Oocytes were collected from goat ovaries, destined for in vitro maturation and distributed into three groups: CIS group, oocytes were immersed in MIV base medium; in Groups Q4 and Q8, oocytes were immersed in the medium of the CIS group, adding 4 μM or 8 μM of quercetin, respectively, and cultured for 24 h at 38.5°C with 5% CO2. The CIS and Q4 groups presented the same percentage of expanded cumulus cells, but the per cent in the Q8 group was significantly lower than that of the other groups (P<0.05). The oocyte retraction rate in the Q8 group was higher (P<0.05) than in the CIS and Q4 groups. Treatment with 8 μM of quercetin presented a lower proportion of expanded oocytes than the CIS group and 4 μM of quercetin (P<0.05). The percentage of MII oocytes was higher in the Q4 group than in the CIS group (P<0.05), but the percentages in the CIS and Q8 groups were similar. The rate of apoptosis was higher in the CIS group than in the other groups (P<0.05). In addition, oocytes matured with 4 μM quercetin showed higher mitochondrial activity than matured oocytes in the CIS and Q8 groups (P<0.05). In conclusion, 4 μM of quercetin can be used as an alternative to cysteamine in the in vitro maturation of goat oocytes.

scholarly journals P0884MYO-INOSITOL HEXAPHOSPHATE PEGYLATION IMPROVES BIOAVAILABILITY BUT REDUCES ITS ANTI-VASCULAR CALCIFICATION EFFECT IN RATS

2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
M Mar Pérez ◽  
Miguel David Ferrer Reynes ◽  
Joaquín Ortega-Castro ◽  
Firas Bassissi ◽  
Joan Perelló ◽  
...  
Keyword(s):  
Vascular Calcification ◽  
Density Functional ◽  
Inositol Phosphates ◽  
Crystal Surface ◽  
Density Functional Theory Calculations ◽  
Sprague Dawley ◽  
Inositol Hexaphosphate ◽  
Sd Rats

Abstract Background and Aims Vascular calcification (VC) is a major contributor to increased morbidity and mortality in End Stage Kidney Disease (ESKD) patients undergoing dialysis. SNF472, a salt of inositol hexaphosphate (InsP6), is a selective calcification inhibitor that interferes in the formation and growth of ectopic hydroxyapatite (HAP). SNF472 is currently in Phase 3 clinical trials for the treatment of calciphylaxis in ESKD patients on dialysis. Inositol-1,2,3,5-tetraphosphate-4,6-bisPEG100 (InsP4bisPEG or INS3001) results from the PEGylation of inositol tetraphosphate (InsP4) with polyethylene glycol (PEG) 100. Our aim was to compare the relative bioavailability of SNF472 and InsP4bisPEG and their efficacy in the inhibition of calcification in silico, in vitro and in vivo. Method Subcutaneous (10 mg/kg) pharmacokinetics of InsP4bisPEG and SNF472 were assessed in Sprague Dawley (SD) rats. To evaluate the adsorption binding affinity (Eads) of SNF472, InsP4bisPEG and other inositol phosphates to the HAP crystal surface, computational studies were performed using Density Functional Theory calculations with DMOL3 (MS2016). The in vitro efficacy of the compounds was evaluated using a pharmacodynamic assay to measure the calcification potential of human plasma. An in vivo efficacy study (calcification induced by 3 consecutives daily s.c. administrations of 150 kIU/kg vitamin D3) was performed with SD rats receiving s.c. vehicle, or equimolar doses (36 µmol/kg) of SNF472 or InsP4bisPEG once daily. Results The PEGylation of inositol tetraphosphate in positions 4 and 6 increased the exposure and t1/2 of the compound when given subcutaneously compared to SNF472. Molecular modelling revealed that SNF472 binds to the HAP surface with higher affinity than InsP4bisPEG and INSP4 (ΔEads=-352 kcal/mol for SNF472, ΔEads=-177 kcal/mol for InsP4bisPEG and ΔEads=-146 Kcal/mol for InsP4, taking inositol as reference). These results were correlated with the inhibition of calcium phosphate crystallization in plasma in vitro. SNF472 treated animals presented significantly lower calcium levels in aorta, which were 38% and 55% lower than placebo and InsP4bisPEG treated animals, respectively. Conclusion The differential pharmacokinetic profile of InsP4bisPEG (INS3001) does not translate into higher, but lower, efficacy than SNF472 against vascular calcification when comparing equimolar doses.

scholarly journals The sites of hydrolysis of dipeptides containing leucine and glycine by rat jejunum in vitro

1969 ◽  
Vol 114 (4) ◽  
pp. 855-861 ◽  
Author(s):  
E. B. Fern ◽  
R. C. Hider ◽  
D. R. London
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
The Other ◽  
Peptidase Activity ◽  
Rat Jejunum ◽  
Effective Inhibitor ◽  
Inhibitory Effects ◽  
Molar Basis ◽  
Hydrolysis Of

1. The effect of peptides containing leucine and glycine on accumulation of leucine and glycine by everted jejunal rings was studied. 2. It was shown that, on a molar basis, leucyl-leucine is a more effective inhibitor of uptake of [14C]leucine than is either leucylglycine or glycyl-leucine. These latter dipeptides behave alike. 3. The concentration of the dipeptides and their constituent amino acids in both the incubation medium and the tissue has been followed in these experiments by amino acid analysis. No leucine-containing peptides were observed in the tissue. 4. The inhibitory effects of the mixed dipeptides are altered by pH changes in an analogous way to the alterations in peptidase activity. 5. The experimental results indicate that leucine-containing peptides are hydrolysed before the transport step. 6. Glycylglycine, on the other hand, has only a small effect on the accumulation of glycine, although large amounts of the peptide accumulate unchanged in the tissue. This suggests that glycylglycine is taken up by a different mechanism to that for the leucine dipeptides.

Effect of oat saponins and different types of dietary fibre on the digestion of carbohydrates

1995 ◽  
Vol 74 (2) ◽  
pp. 229-237 ◽  
Author(s):  
G. Önning ◽  
N.-G. Asp
Keyword(s):  
Dietary Fibre ◽  
Guar Gum ◽  
The Other ◽  
Lactase Activity ◽  
Proximal Small Intestine ◽  
Different Types ◽  
Hydrolysis Of ◽  
Detergent Effect

The effects of oat saponins (a mixture of avenacosides A and B) and dietary fibre (cellulose and guar gum) on the disaccharidase activities in the proximal small intestine of the rat were investigated. The influence of avenacosides A and B on the activity of disaccharidases and α-amylase (EC 3·2·1·1) was also studied in vitro. In vivo, oat diets with three avenacoside contents (negligible, normal and twice normal) were used. No significant differences in sucrase (EC 3·2·1·48), maltase (EC 3·2·1·20), trehalase (EC 3·2·1·28) and lactase (EC 3·2·1·21) activities were found between the oat groups after 19 d feeding. The rats that were given cellulose tended to have higher disaccharidase activities compared with the other groups. The avenacosides inhibited the lactase activity significantly in vitro while no or small effects on the other disaccharidases were found. In contrast, the in vitro hydrolysis of starch by α-amylase was increased in the presence of saponins, probably due to their detergent effect. Thus, the in vitro studies showed that the avenacosides could influence the enzyme activities. In vivo, these effects are probably minor due to the low avenacoside concentrations found in oats.

Enhancement of ADP-induced Platelet Aggregation by Adrenaline in Vivo and Its Prevention

1973 ◽  
Vol 29 (02) ◽  
pp. 490-498 ◽  
Author(s):  
Hiroh Yamazaki ◽  
Itsuro Kobayashi ◽  
Tadahiro Sano ◽  
Takio Shimamoto
Keyword(s):  
Platelet Count ◽  
Platelet Aggregation ◽  
Platelet Rich Plasma ◽  
The Other ◽  
Endothelial Surface ◽  
Important Interaction ◽  
Blood Coagulability ◽  
The Difference

SummaryThe authors previously reported a transient decrease in adhesive platelet count and an enhancement of blood coagulability after administration of a small amount of adrenaline (0.1-1 µg per Kg, i. v.) in man and rabbit. In such circumstances, the sensitivity of platelets to aggregation induced by ADP was studied by an optical density method. Five minutes after i. v. injection of 1 µg per Kg of adrenaline in 10 rabbits, intensity of platelet aggregation increased to 115.1 ± 4.9% (mean ± S. E.) by 10∼5 molar, 121.8 ± 7.8% by 3 × 10-6 molar and 129.4 ± 12.8% of the value before the injection by 10”6 molar ADP. The difference was statistically significant (P<0.01-0.05). The above change was not observed in each group of rabbits injected with saline, 1 µg per Kg of 1-noradrenaline or 0.1 and 10 µg per Kg of adrenaline. Also, it was prevented by oral administration of 10 mg per Kg of phenoxybenzamine or propranolol or aspirin or pyridinolcarbamate 3 hours before the challenge. On the other hand, the enhancement of ADP-induced platelet aggregation was not observed in vitro, when 10-5 or 3 × 10-6 molar and 129.4 ± 12.8% of the value before 10∼6 molar ADP was added to citrated platelet rich plasma (CPRP) of rabbit after incubation at 37°C for 30 second with 0.01, 0.1, 1, 10 or 100 µg per ml of adrenaline or noradrenaline. These results suggest an important interaction between endothelial surface and platelets in connection with the enhancement of ADP-induced platelet aggregation by adrenaline in vivo.

Reaction of Acetaldehyde with Human Platelets

1992 ◽  
Vol 67 (01) ◽  
pp. 126-130 ◽  
Author(s):  
Olivier Spertini ◽  
Jacques Hauert ◽  
Fedor Bachmann
Keyword(s):  
Platelet Aggregation ◽  
Inhibitory Action ◽  
Ex Vivo ◽  
Platelet Rich Plasma ◽  
Shape Change ◽  
Reaction Medium ◽  
Human Platelets ◽  
Membrane Glycoproteins ◽  
Neutral Ph

SummaryPlatelet function defects observed in chronic alcoholics are not wholly explained by the inhibitory action of ethanol on platelet aggregation; they are not completely reproduced either in vivo by short-term ethanol perfusion into volunteers or in vitro by the addition of ethanol to platelet-rich plasma. As acetaldehyde (AcH) binds to many proteins and impairs cellular activities, we investigated the effect of this early degradation product of ethanol on platelets. AcH formed adducts with human platelets at neutral pH at 37° C which were stable to extensive washing, trichloracetic acid hydrolysis and heating at 100° C, and were not reduced by sodium borohydride. The amount of platelet adducts formed was a function of the incubation time and of the concentration of AcH in the reaction medium. At low AcH concentrations (<0.2 mM), platelet bound AcH was directly proportional to the concentration of AcH in the reaction medium. At higher concentrations (≥0.2 mM), AcH uptake by platelets tended to reach a plateau. The amount of adducts was also proportional to the number of exposures of platelets to pulses of 20 pM AcH.AcH adducts formation severely impaired platelet aggregation and shape change induced by ADP, collagen and thrombin. A positive correlation was established between platelet-bound AcH and inhibition of aggregation.SDS-PAGE analysis of AcH adducts at neutral pH demonstrated the binding of [14C]acetaldehyde to many platelet proteins. AcH adduct formation with membrane glycoproteins, cytoskeleton and enzymes might interfere with several steps of platelet activation and impair platelet aggregation.This in vitro study shows that AcH has a major inhibitory action on platelet aggregation and may account for the prolonged ex vivo inhibition of aggregation observed in chronic alcoholics even in the absence of alcoholemia.

ALDOSTERONE STIMULATION IN VITRO

1965 ◽  
Vol 50 (2) ◽  
pp. 301-309 ◽  
Author(s):  
Jürg Müller
Keyword(s):  
Ammonium Chloride ◽  
Human Urine ◽  
Incubation Medium ◽  
The Other ◽  
Ammonium Ions ◽  
Response Curves ◽  
Urine Extract ◽  
Similar Dose ◽  
Aldosterone Production

ABSTRACT An extract of human urine, which was previously shown to stimulate aldosterone production by rat adrenal sections, was further purified. Evidence was obtained that its aldosterone-stimulating effect was due to the presence of ammonium ions. Addition of ammonium chloride and of urine extract to the incubation medium caused identical increases in aldosterone production in vitro. In addition to ammonium ions, rubidium and caesium ions also stimulated aldosterone production up to 250% that of control values without a significant effect on corticosterone production. Similar dose-response curves were obtained when increasing concentrations of potassium, ammonium, rubidium and caesium ions were tested. Aldosterone production was maximal at concentrations of 7 mval/1 and was significantly lower at higher concentrations. When ammonium chloride and ACTH were simultaneously added to the incubation medium, the production of aldosterone and of corticosterone was lower than with ACTH alone. On the other hand, the stimulating activity on aldosterone and corticosterone production by »TPN« (NADP) and glucose-6-phosphate was enhanced by the simultaneous addition of ammonium chloride.

EFFECT OF ACTINOMYCIN D ON TSH-INDUCED STIMULATION OF THYROIDAL PROTEIN SYNTHESIS IN THE RAT

1974 ◽  
Vol 77 (1) ◽  
pp. 64-70 ◽  
Author(s):  
Gustav Wägar
Keyword(s):  
Protein Synthesis ◽  
Actinomycin D ◽  
The Other ◽  
Leucine Incorporation ◽  
Short Term ◽  
Other Hand ◽  
Thyroid Glands ◽  
Translational Level ◽  
Stimulation Of

ABSTRACT Whether the short-term regulation of thyroidal protein synthesis by TSH occurs at the transcriptional or the translational level was tested by measuring the effect of actinomycin D (act D) on the TSH-induced stimulation of L-14C-leucine incorporation into the thyroidal proteins of rats. TSH was injected 6 h before the rats were killed. The thyroid glands were then removed and incubated in vitro in the presence of L-14C-leucine for 2 h. The pronounced stimulation of leucine incorporation in the TSH-treated animals was depressed as compared with controls but still significant even when the animals had been pre-treated with 100 μg act D 24 and 7 h before sacrifice. On the other hand, act D strongly decreased incorporation of 3H-uridine into RNA. Short-term regulation of thyroidal protein synthesis by TSH appears to be partly but not wholly dependent on neosynthesis of RNA. Hence regulation may partly occur at the translation level of protein synthesis.

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