scholarly journals Chemical factors affecting the intestinal absorption of zinc in vitro and in vivo

1983 ◽  
Vol 50 (2) ◽  
pp. 317-324 ◽  
Author(s):  
C. J. Seal ◽  
F. W. Heaton
Keyword(s):  
Picolinic Acid ◽  
Unit Weight ◽  
Faecal Excretion ◽  
Factors Affecting ◽  
Zn Uptake ◽  
Zn Concentration ◽  
Chemical Factors ◽  
Rat Duodenum

1. Everted sacs of rat duodenum and ileum were used to study the effect of anions and organic ligands on the absorption of zinc. The uptake per unit weight of tissue was greater in duodenum than ileum, and it was influenced by the Zn concentration and pH of the incubation medium.2. The Zn uptake from inorganic salts in simple buffered medium varied in the order zinc sulphate > zinc chloride > zinc phosphate. Zinc acetate was more effective and zinc citrate less effective than ZnCl2. Addition of aspartic acid or histidine to ZnCl2 increased the uptake but galactose or lactose decreased it. 2-Picolinic acid greatly increased the Zn uptake but 4-picolinic acid reduced it.3. When incubated with intestinal sacs after incorporation into a synthetic rat diet, only ZnSO4 and 2-picolinic acid increased Zn uptake compared with ZnCl2, but zinc citrate and 4-picolinic acid still tended to decrease it.4. Metabolic balance studies showed no significant differences in the faecal excretion, total excretion or retention of Zn between rats receiving diets containing different forms of Zn. ZnSO4, zinc citrate and particularly 2-picolinic acid increased the urinary excretion of Zn.5. The significance of these results is discussed in relation to the suitability of methods for investigating Zn absorption and the importance of Zn-binding ligands.

scholarly journals The effects of dietary ligands on zinc uptake at the porcine intestinal brush-border membrane

1990 ◽  
Vol 64 (3) ◽  
pp. 733-741 ◽  
Author(s):  
A. J. Turnbull ◽  
P. Blakeborough ◽  
R. P. H. Thompson
Keyword(s):  
Brush Border ◽  
Brush Border Membrane ◽  
Membrane Vesicles ◽  
Intestinal Brush Border Membrane ◽  
Intestinal Brush Border ◽  
Zn Uptake ◽  
Zn Concentration ◽  
Vitro Model

Intestinal brush-border-membrane vesicles were prepared from the porcine small bowel by magnesium precipitation and differential centrifugation, and were functionally intact. The influence of dietary ligands on 65Zn uptake was determined using a 65Zn concentration of 5 μm, an incubation time of 1 min and a reaction temperature of 27°, with a rapid filtration technique. At this low Zn concentration the addition of an excess of folate, histidine or glucose had no effect on Zn uptake. Addition of picolinate, citrate and phytate to the incubation medium significantly reduced Zn uptake at all concentrations of ligand examined. Any inhibitory effects of folic acid in vivo may thuss be due to a mucosal rather than lumen interaction. Those ligands inhibiting absorption may have done so through the formation of Zn-ligand complexes, which are either insoluble, or which reduce the binding of Zn to its mucosal receptor. This in vitro model of Zn absorption is useful for comparing the effects of potential Zn-binding ligands in the diet.

scholarly journals Hepatic zinc in metallothionein-null mice following zinc challenge: in vivo and in vitro studies

1995 ◽  
Vol 309 (1) ◽  
pp. 25-31 ◽  
Author(s):  
P Coyle ◽  
J C Philcox ◽  
A M Rofe
Keyword(s):  
Cell Culture ◽  
Cell Surface ◽  
Plasma Concentrations ◽  
Isolated Hepatocytes ◽  
Cultured Hepatocytes ◽  
Zn Uptake ◽  
Parallel Increase ◽  
Zn Concentration

Hepatic zinc uptake and accumulation were compared in freshly isolated and cultured hepatocytes prepared from control (MT+/+) and metallothionein (MT)-null (MT-/-) mice. In freshly isolated hepatocytes, rapid (10-15 min) exchange of 65Zn was proportional to the Zn concentration in the medium and occurred to the same extent in hepatocytes from MT+/+ and MT-/- mice. In 24 h culture experiments with MT+/+ and MT-/- hepatocytes it was shown that approx. 40% of newly acquired cell-associated Zn was attached to the cell surface and not internalized. In MT+/+ and MT-/- hepatocyte cultures, internalized Zn (intZn) increased in proportion to extracellular Zn. Zn accumulation in MT-/- hepatocytes was only 60% that of MT+/+ cells. Addition of 1 microM dexamethasone (Dex) and recombinant mouse interleukin-6 (IL-6; 100 units/ml) increased MT accumulation by 8.6-fold in MT+/+ hepatocytes (at 50 microM Zn) and there was an associated parallel increase in intZn. Dex and IL-6 did not increase intZn in the MT-/- hepatocytes. At 16 h after an intraperitoneal injection of 5 micrograms/g Zn, plasma and urine Zn concentrations were 69 +/- 10 microM and 86 +/- 25 microM respectively in MT-/- mice (n = 10) and 27 +/- 1 microM and 23 +/- 4 microM respectively in MT+/+ controls (n = 9) (P < 0.001, plasma; P < 0.05, urine). Hepatic cytosolic Zn concentrations doubled in MT+/+ mice and increased by a significant 15% in MT-/- mice. There was no increase in hepatic Zn (dry wt.) concentrations or in total hepatic Zn, demonstrating that the increase in cytosolic Zn in MT-/- mice was due to hepatic water loss rather than net Zn uptake. It appears that even at extreme plasma concentrations of Zn, little if any accumulates within the liver when there is no MT available for its sequestration. That this is not fully demonstrated in vitro is probably due to nature of cell culture, where organ architecture is lost and the external protein binding milieu is less complex.

scholarly journals Silver Nanoparticles and Their Antibacterial Applications

2021 ◽  
Vol 22 (13) ◽  
pp. 7202
Author(s):  
Tamara Bruna ◽  
Francisca Maldonado-Bravo ◽  
Paul Jara ◽  
Nelson Caro
Keyword(s):  
Silver Nanoparticles ◽  
Antibacterial Agents ◽  
Multidrug Resistant ◽  
Secondary Effects ◽  
Cytotoxic Effects ◽  
Factors Affecting ◽  
Gram Positive Bacteria ◽  
Resistant Strains

Silver nanoparticles (AgNPs) have been imposed as an excellent antimicrobial agent being able to combat bacteria in vitro and in vivo causing infections. The antibacterial capacity of AgNPs covers Gram-negative and Gram-positive bacteria, including multidrug resistant strains. AgNPs exhibit multiple and simultaneous mechanisms of action and in combination with antibacterial agents as organic compounds or antibiotics it has shown synergistic effect against pathogens bacteria such as Escherichia coli and Staphylococcus aureus. The characteristics of silver nanoparticles make them suitable for their application in medical and healthcare products where they may treat infections or prevent them efficiently. With the urgent need for new efficient antibacterial agents, this review aims to establish factors affecting antibacterial and cytotoxic effects of silver nanoparticles, as well as to expose the advantages of using AgNPs as new antibacterial agents in combination with antibiotic, which will reduce the dosage needed and prevent secondary effects associated to both.

Factors affecting in vitro and in vivo antioxidant effects. Experimental conditions and nature of oxidants determine antioxidant efficacy

2021 ◽  
pp. 1-9
Author(s):  
Etsuo Niki
Keyword(s):  
Biological Molecules ◽  
Experimental Conditions ◽  
Factors Affecting ◽  
Beneficial Effects ◽  
Multiple Oxidants ◽  
Antioxidant Effects

Reactive oxygen and nitrogen species have been implicated in the onset and progression of various diseases and the role of antioxidants in the maintenance of health and prevention of diseases has received much attention. The action and effect of antioxidants have been studied extensively under different reaction conditions in multiple media. The antioxidant effects are determined by many factors. This review aims to discuss several important issues that should be considered for determination of experimental conditions and interpretation of experimental results in order to understand the beneficial effects and limit of antioxidants against detrimental oxidation of biological molecules. Emphasis was laid on cell culture experiments and effects of diversity of multiple oxidants on antioxidant efficacy.

Maturation, iron deficiency, and ligands in enteric radioiron transport in vitro

1963 ◽  
Vol 204 (1) ◽  
pp. 171-175 ◽  
Author(s):  
W. S. Ruliffson ◽  
J. M. Hopping
Keyword(s):  
Ascorbic Acid ◽  
Iron Deficiency ◽  
Iron Absorption ◽  
Deficiency Anemia ◽  
Anaerobic Incubation ◽  
Reverse Effect ◽  
Factors Affecting ◽  
Everted Gut Sac

The effects in rats, of age, iron-deficiency anemia, and ascorbic acid, citrate, fluoride, and ethylenediaminetetraacetate (EDTA) on enteric radioiron transport were studied in vitro by an everted gut-sac technique. Sacs from young animals transported more than those from older ones. Proximal jejunal sacs from anemic animals transported more than similar sacs from nonanemic rats, but the reverse effect appeared in sacs formed from proximal duodenum. When added to media containing ascorbic acid or citrate, fluoride depressed transport as did anaerobic incubation in the presence of ascorbic acid. Anaerobic incubation in the presence of EDTA appeared to permit elevated transport. Ascorbic acid, citrate, and EDTA all enhanced the level of Fe59 appearing in serosal media. These results appear to agree with previously established in vivo phenomena and tend to validate the in vitro method as one of promise for further studies of factors affecting iron absorption and of the mechanism of iron absorption.

Factors affecting the time of formation of the mouse blastocoele

Development ◽  
1977 ◽  
Vol 41 (1) ◽  
pp. 79-92
Author(s):  
Rosita Smith ◽  
Anne McLaren
Keyword(s):  
Cytochalasin B ◽  
Critical Factor ◽  
Cell Number ◽  
Experimental Manipulation ◽  
Factors Affecting ◽  
Elapsed Time ◽  
Developmental Age ◽  
Culture Formation

In normal mouse embryos developing in vivo, the first appearance of the blastocyst cavity was found to be associated more closely with developmental age, judged by cell number, than with chronological age, i.e. elapsed time since ovulation. When development was slowed by in vitro culture, formation of the blastocoele was delayed. However, cell number itself was not a critical factor, since the number of cells per embryo could be doubled or tripled or halved by experimental manipulation without substantially affecting the timing of blastocoele formation. Experiments in which one cell division was suppressed with cytochalasin-B, leading to tetraploidy, showed that the number of cell divisions since fertilization was also not critical. A possible role is suggested either for nucleocytoplasmic ratio, or for the number of nuclear or chromosomal divisions or DNA replications since fertilization, all of which increase during cleavage.

In vitro characterisation of ultrasound-induced heating effects in the mother and fetus: A clinical perspective

Ultrasound ◽  
2020 ◽  
pp. 1742271X2095319
Author(s):  
Stephanie F Smith ◽  
Piero Miloro ◽  
Richard Axell ◽  
Gail ter Haar ◽  
Christoph Lees
Keyword(s):  
Temperature Increase ◽  
Skin Surface ◽  
Maximum Temperature ◽  
Factors Affecting ◽  
Bone Interface ◽  
Heating Effects ◽  
Power Setting ◽  
Lower Temperature

Introduction The quantification of heating effects during exposure to ultrasound is usually based on laboratory experiments in water and is assessed using extrapolated parameters such as the thermal index. In our study, we have measured the temperature increase directly in a simulator of the maternal–fetal environment, the ‘ISUOG Phantom’, using clinically relevant ultrasound scanners, transducers and exposure conditions. Methods The study was carried out using an instrumented phantom designed to represent the pregnant maternal abdomen and which enabled temperature recordings at positions in tissue mimics which represented the skin surface, sub-surface, amniotic fluid and fetal bone interface. We tested four different transducers on a commercial diagnostic scanner. The effects of scan duration, presence of a circulating fluid, pre-set and power were recorded. Results The highest temperature increase was always at the transducer–skin interface, where temperature increases between 1.4°C and 9.5°C were observed; lower temperature rises, between 0.1°C and 1.0°C, were observed deeper in tissue and at the bone interface. Doppler modes generated the highest temperature increases. Most of the heating occurred in the first 3 minutes of exposure, with the presence of a circulating fluid having a limited effect. The power setting affected the maximum temperature increase proportionally, with peak temperature increasing from 4.3°C to 6.7°C when power was increased from 63% to 100%. Conclusions Although this phantom provides a crude mimic of the in vivo conditions, the overall results showed good repeatability and agreement with previously published experiments. All studies showed that the temperature rises observed fell within the recommendations of international regulatory bodies. However, it is important that the operator should be aware of factors affecting the temperature increase.

Hyperglycemic athymic nude mice: factors affecting in vitro insulin secretion

1992 ◽  
Vol 263 (6) ◽  
pp. E1131-E1133
Author(s):  
A. Zeidler ◽  
P. Edwards ◽  
J. Goldman ◽  
S. Kort ◽  
W. P. Meehan ◽  
...  
Keyword(s):  
Animal Model ◽  
Insulin Secretion ◽  
Insulin Dependent Diabetes Mellitus ◽  
Dependent Diabetes Mellitus ◽  
Factors Affecting ◽  
In Vitro Insulin Secretion ◽  
Insulin Secretion In Vitro ◽  
And Control

The strain of athymic nude male mice (ANM) developed at the University of Southern California (USC) exhibits spontaneous hyperglycemia and relative hypoinsulinemia in vivo. To investigate factors that influence insulin secretion in this animal model of non-insulin-dependent diabetes mellitus, we utilized the isolated perfused mouse pancreas of the ANM-USC and control BALB/c mice. We compared in vitro glucose-induced insulin secretion in ANM-USC and control mice, inhibition of secretion by somatostatin, and variability of insulin secretion over the two-year period it took to complete these experiments. Glucose-induced insulin secretion from the isolated pancreas was biphasic in both ANM-USC and controls. Insulin secretion was quantitatively equal to or greater than control mice, depending on the phase of secretion analyzed and the source of the control mice. In contrast to pancreases of control mice, insulin secretion from ANM-USC pancreases was relatively resistant to inhibition of insulin secretion by somatostatin. Variability in insulin secretion over the two years in which these experiments were performed was greater from pancreases of control than that observed from pancreases of the ANM-USC. The hyperglycemic ANM-USC mouse does not demonstrate diminished insulin secretion in vitro yet is relatively hypoinsulinemic in vivo. Thus circulating factors other than somatostatin might contribute to the insulinopenic stage in this animal model.

Effect of hypophysectomy on calcium transport by rat duodenum.

1977 ◽  
Vol 232 (2) ◽  
pp. E229
Author(s):  
E L Krawitt ◽  
A S Kunin ◽  
H W Sampson ◽  
B F Bacon
Keyword(s):  
Calcium Transport ◽  
Calcium Absorption ◽  
Plasma Flux ◽  
Perfusion Technique ◽  
Intestinal Length ◽  
Absorption Studies ◽  
Luminal Perfusion ◽  
Rat Duodenum

To examine the effect of hypophysectomy on intestinal calcium absorption, studies were performed on immature rats 7, 14, and 21 days after hypophysectomy. Duodenal calcium transport was measured in vitro utilizing everted gut sacs and in vivo by a luminal perfusion technique. Hypophysectomy produced no differences in the ability of everted gut sacs to transport calcium. Similarly, when in vivo transport data were expressed on the basis of intestinal length, no significant differences were noted. However, when transport data were expressed on the basis of mucosal weight, increases in absorption and lumen-to-plasma fluxes were apparent in hypophysectomized animals. No differences were seen in plasma-to-lumen fluxes. The results indicate that when the transport data are corrected for mass of intestinal mucosa, the duodenum from hypophysectomized animals absorbs calcium more avidly due to an increase in lumen-to-plasma flux.

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