Temperature-induced fibrillogenesis and gelation of fibrinogen mediated by calcium salts

It is shown that many substances may produce heart block if they be perfused through the heart at a too high pressure.The salts of potassium may be divided into two groups with reference to their action on the heart of the frog. This division is determined by the presence or absence of a “contraction effect,” when the salts are employed in high concentration. The absence of this “contraction effect” with the one group of salts is shown to be due to their action on some of the calcium salts of cardiac muscle. All the salts temporarily abolish the rhythmical activity of the heart.The division of the salts into these two groups is in accord with their action on the sartorius muscle.Potassium salts give rise to two types of contraction in the cardiac muscle of the frog, viz., the “tonic contraction” and the “contraction effect.” The former could be produced by all the salts of potassium examined, and seemed to be in some way associated with the rhythmical contraction process; the latter was the determining factor for dividing the salts into two groups, and could be produced in the non‐beating heart.There is a seasonal, and also individual, difference in the action of a 0·225 per cent. solution of potassium chloride on the frog's heart. In any heart, and at any season, the seasonal differences found in the fresh heart may be reversed or paralleled by appropriate treatment with calcium or potassium salts. The conclusion is drawn that there are seasonal variations in the balance between the calcium and potassium salts in the heart muscle of the frog. It is possible that temperature may be a factor in bringing about such changes.There are at least three groups of calcium salts in the cardiac muscle of the frog.The salts of one of these groups seem only to be displaced by such potassium salts as the oxalate and citrate. The results obtained after such displacement suggest that these salts are normally concerned in bringing about some limitation of the direct action of potassium salts on heart muscle.The other calcium salts are readily displaced by all potassium salts. Such displacement is followed by derangement of spontaneous contractions and of rhythm, such as to suggest the loss of some form of governing or controlling influence. Since restoration to the normal depends on calcium salts, these would appear to keep the cardiac functions in check in addition to being essential to their initiation. Irregularities of rhythm and contraction may appear independently of each other, and for this reason the calcium salts governing these processes are divided into two separate groups. The calcium salts controlling rhythm also appear to mediate the action of the vagus nerve on the heart.In conclusion, I wish to express my sincere thanks to Professor Gotch for his valuable criticism and advice.

Residents’ journal review

The effects of calcium and magnesium salts were studied on rabbits, cats, guinea pigs, rats and frogs; most extensively, however, on rabbits. Effects were obtained by means of subcutaneous, intravenous or intra-arterial injections; the intravenous method being more extensively employed than the other methods. The infusions were given in solutions of M/1, M/2, M/4, or M/8 concentration. Of the calcium salts we used CaCl2, Ca(No3)2 and Ca(C2H3O2)2; of the magnesium salts, MgSO4, MgCl2, Mg(NO3)2 and Mg(C2H3O2)2.The following are the chief results. Calcium salts hasten and magnesium salts retard the development of the rigor of skeletal muscles. After treatment with calcium salts the rigor may begin twenty minutes after death, and after magnesium treatment it may not begin before the lapse of six or seven hours. In the rigor after injection of a calcium salt the extensors mostly prevail irrespective of the original position. After treatment with magnesium salts the flexors prevail or the animal remains in the ...

1. Young kidney-bean plants were decapitated in the second internode. 2,4-Dichlorophenoxyacetic acid or one of four salts-ammonium, copper, calcium, or magnesium 2,4-dichlorophenoxyacetate-was applied to the cut surface in 0.5% concentration by weight in lanolin paste. Observations were made of material grown for a period of 30 days after treatment. 2. Gross response showed characteristic differences among the tumors. Treatments with 2,4-D and with the ammonium salt resulted in relatively deep, club-shaped tumors. Proliferation was entirely below the cut surface. The tumor induced by the copper salt was likewise formed below the cut surface but Was somewhat shallower. Those induced by calcium and magnesium salts were broadly flared at the cut surface and gradually tapered below. Growth above the cut surface occurred with both of the latter substances but to a more marked degree with the magnesium salt. 3. Histological responses in the early stages showed considerable similarity. In parenchymatous tissues of the inner cortex including the endodermis, of the pericycle, phloem, cambial zone, xylem, and rays, proliferation was initiated soon after treatment. Response induced by the magnesium salt was earlier and more marked than in other treatments, less so with the calcium salt, and least with the ammonium salt and with 2,4-D. 4. Study of the tumor as a whole disclosed a pattern of zonation for all treatments. At upper levels a zone of limited proliferation was found in the responses to 2,4-D and to the ammonium and copper salts. This zone was lacking in the other responses. A zone of major proliferation occupied the intermediate levels below the zone of limited proliferation in treatments with 2,4-D and with the ammonium and copper salts but was found at upper levels in the tumors induced by the calcium and magnesium salts. In response to the magnesium salt this zone Was only poorly represented. With all substances a root zone was formed at next lower levels, and below the roots a zone of minor proliferation terminated the tumor. Comparison on the basis of zonation disclosed a consistent sequence among the substances according to the characteristics of the responses induced: 2,4-D and the ammonium, copper, calcium, and magnesium salts. This, same series was duplicated in gross responses and in details of histological responses. 5. Maturation was earliest and most marked in the treatment with the magnesium salt and least with the ammonium salt and with 2,4-D. In the zone of limited proliferation maturation occurred early, was mainly as parenchyma, and was soon followed by collapse. Maturation in the zone of major proliferation was longest delayed. Many of the derivatives differentiated as parenchyma except at levels of transition to lower zones. In the root zone the rays organized as root primordia remained active until the death of the tumor 3 weeks or more after treatment. Proliferated tissues of vascular bundles and associated endodermis and cortical parenchyma both in the root zone and in the zone of minor proliferation exhibited complicated patterns of differentiation into tracheids, parenchyma, vascular bundles, and meristematic areas. 6. Characteristic differences in histological responses to the different substances are discussed. The most pronounced differences were found in decapitated stems treated with the magnesium salt. However, no response induced by one substance was entirely absent in the reaction to another substance. All responses appeared to fall within the range of effects distinctive for 2,4-D. Independent effects of the different cations on stem responses were also considered. 7. Zonation is interpreted as an expression of a concentration gradient. On the basis of this interpretation the effectiveness of the growth-regulating substance was greatly modified by the form of the salt which was applied.

Physicochemical properties of plant-based cheese alternatives fortified with calcium

To investigate the influencing mechanisms of calcium and magnesium on the solid products of biomass torrefaction, cellulose was selected as the feedstock in this article. The experiments were conducted in the holding temperature range of 200 °C to 300 °C under the atmosphere of nitrogen. Based on the impregnation methods (chlorides, hydroxides, and acetates of Ca and Mg), the results showed that the solid product yield of torrefacted cellulose impregnated with calcium or magnesium salts was lower than that of raw cellulose torrefaction at 200 °C to 275 °C. However, at 300 °C, the solid product yield of impregnated cellulose torrefaction was higher. During torrefaction, the CaCl2 had a stronger effect than other calcium salts. The Mg(CH3COO)2 had less of an effect than other magnesium salts. The crystallinity of the torrefied cellulose with impregnated calcium or magnesium salts was considerably reduced from 51.1% (raw cellulose) to 7.7% (addition of CaCl2), 34.8% (addition of Ca(OH)2), 28.6% (addition of Ca(CH3COO)2), 9.2% (addition of MgCl2), 13.6% (addition of Mg(OH)2), and 12.0% (addition of Mg(CH3COO)2). The results of the thermal gravimetric analysis showed that the impregnated calcium or magnesium salts dramatically reduced the activation energy of the torrefaction.

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Four experiments were conducted to determine the effects of supplemental rumen-protected fat in feedlot rations. The first experiment tested the effects of supplemental calcium and magnesium salts of fatty acids on ruminal fermentation and duodenal fatty acid flow in beef steers fed forage-free diets. These saponified fatty acids did not disrupt ruminal fermentation but provided little protection from ruminal biohydrogenation under these conditions. The second experiment evaluated the effects of increasing levels of calcium salts on feedlot performance and carcass characteristics. A moderate (6.2%) level of calcium salts had no effect on average daily gain (ADG) or feed efficiency (FE). However, ADG and FE were decreased when calcium salts were fed at 8.7% of the diet. The third experiment evaluated the effects of calcium salt supplementation in traditional and forage-free feedlot diets on feedlot performance and carcass characteristics. Supplemental rumen-protected fat had no effect on ADG or FE but decreased ribeye area (REA) when fed at 6.5% of the diet. The fourth experiment evaluated the effects of feeding calcium salts on feedlot performance, carcass characteristics, and blood metabolites that affect the growth of feedlot animals. Supplemental rumen-protected fat decreased ADG and intake with no effect on FE when fed at 6.5% of the diet. In addition, calcium salts had little effect on carcass measurements and blood metabolites.

Physiological Disposition of Fenoprofen in Man I: Pharmacokinetic Comparison of Calcium and Sodium Salts Administered Orally

Oxygen consumption measurement was used to study potential oxidative degradation reactions occurring in wooden artefacts from the Viking age Oseberg collection in Norway. Model samples of fresh birch were impregnated with iron, calcium and alum salts to mimic concentrations of such compounds found in Oseberg artefacts and to assess their effect on oxygen consumption rates. The results showed that heated impregnation with alum salt (KAl(SO4)2·12H2O) significantly increased the rate of oxygen consumption, confirming a previously observed link between alum-treatment and wood oxidation. The presence of iron salts in alum-treated wood specimens, even at low concentrations, also substantially increased the oxidation rate. However, the mechanism by which this occurred appeared to be influenced by the alum-treatment. Samples treated with both iron and calcium salts were also studied, in order to investigate a proposed inhibition of iron-induced oxidation by calcium ions. However, these did not appear to consume oxygen at significantly different rates. In Oseberg samples, a large variation in oxygen consumption rates from 0.48 to an apparent 8.2 μg O2 (g wood)−1 day−1 was observed, and these values were consistently higher than those for reference fresh wood. The results demonstrated that oxygen consumption measurement is a viable method of evaluating chemical stability in this case, but is best applied to model samples with limited compositional variability.

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Alkalis produce two types of ventricular contraction. The one produced by small concentrations of alkali (Gaskell) depends on the calcium salts in the perfusing medium; the other is not so dependent. It is an alkali rigor.Acids produce two main types of ventricular contraction. Certain organic acids produce a slow developing rigor contraction which destroys the contractile material.Certain inorganic acids produce a quickly developing contraction capable of repetition.Lactic acid produces a contraction of intermediate type.The perfusion of acids through the heart changes the normal reaction of the ventricular wall to sufficiently concentrated solutions of calcium or potassium salts. The change suggested is that of altering the permeability of some membrane or membranes to these salts.The physiological neutralisation of an acid is not adequately performed by a bicarbonate but it is by a phosphate.Under the conditions of these experiments the hydrogen ion adversely influences those functions of the heart subserved by the sarcoplasm and its junction with other contractile elements.The actions of the hydrogen ion are determined by the displacement of other inorganic elements in the tissues, calcium salts being important elements so displaced.

Maleated dipentene (DPMA) and acrylopimaric acid (APA) were prepared by the Diels–Alder addition of dipentene with maleic anhydride and gum rosin with acrylic acid, respectively, and subsequently converted to the corresponding zinc salts (DPMA-Zn, APA-Zn) and calcium salts (DPMA-Ca, APA-Ca). Their chemical structures were confirmed by FT-IR analysis. The effects of the mixed DPMA-Ca/DPMA-Zn and APA-Ca/APA-Zn stabilizers on the PVC thermal stability were studied. In comparison, two commercial products, calcium stearate (CaSt2) and zinc stearate (ZnSt2), and two homemade salts of a dimer fatty acid (C36DA), zinc salt (C36DA-Zn) and calcium salt (C36DA-Ca), were also employed as controls in the study of PVC thermal stabilization. The thermal stability of PVC samples was determined using thermogravimetric analysis (TGA), Congo red test and discoloration test. Dynamic mechanical properties of the PVC compounds were also studied. The results showed that PVC compounds stabilized by the mixed DPMA-Ca/DPMA-Zn and APA-Ca/APA-Zn stabilizers displayed comparable modulus and glass transition temperatures but exhibited overall superior thermal stability compared with the CaSt2/ZnSt2 stabilized PVC.

Calcium phosphate cements (CPCs) are usually modified by organic/inorganic additives to improve their mechanical performance and to adjust their rheological and setting properties to clinical requirements. In this work we used several nontoxic and biocompatible α-hydroxylated organic acids (glycolic, lactic, malic, tartaric, and citric acids) and their calcium and sodium salts for the modification of CPC. The unmodified cement used in this study consisted of an equimolar powder mixture of tetracalcium phosphate (TTCP) and dicalcium phosphate anhydrous (DCPA) mixed with water at a powder mass/liquid volume ratio of 3.3 g/mL. It had a compressive strength of 38 MPa and an initial setting time of 8 min. The free acids as cement liquids had mainly a detrimental effect on the strength of the cement and led to a decreased setting time around 2−4 min, while the calcium salts did not significantly alter the cement properties. However, the sodium salts of the oligocarboxylic acids (malic, tartaric, and citric acids) resulted in a liquefying effect combined with a strong reinforcement of the mechanical strength, such that compressive strength increased to 78−99 MPa. The liquefying effect and prolonged setting time of these compounds was thought to derive from a strong increase in the surface charge of both reactants and the reaction product hydroxyapatite as determined by ζ potential, which increased from about −15 and −18 mV in pure water for TTCP and DCPA, respectively, to values around −40 to −50 mV. In contrast, the calcium salts did not alter ζ potentials due to the formation of neutral and stable complexes in aqueous solution.

Ruminal biohydrogenation in Holstein cows fed soybean fatty acids as amides or calcium salts.

The objective of this study was to determine the effects of calcium salts on growth of Botryosphaeria dothidea and incidence of white rot. The relative virulence of five B. dothidea isolates was determined using the apple cultivars Fuji, Gala, Golden Delicious, Liberty, and York. Cultivar and isolate differences in lesion diameter were significant. Cultivar differences occurred between Fuji, which was most susceptible, and Gala, which was least susceptible. Isolates PA-1 and PA-2 were most virulent. Isolate PA-4 was used at conidia concentrations of 1 × 104, 1 × 105, 1 × 106, and 1 × 107 conidia per ml on Golden Delicious fruit to test the effects of four inoculum concentrations on fruit infection by B. dothidea. Incidence of infection on detached, nonwounded fruit increased as inoculum concentration increased. The effects of four calcium salts on infection of wounded fruit by conidia were examined in field and laboratory experiments. In the field experiments, lesion size was slightly reduced on fruit treated with either calcium hydroxide or calcium silicate after wounding and prior to inoculation with conidia of B. dothidea, whereas lesions that developed at wounds treated with calcium chloride or calcium propionate were similar to those of the control. In the laboratory experiments, in several instances supplementation with calcium salts resulted in increased lesion diameter relative to the control. Two of five isolates tested showed increased percent germination with all four calcium salts, and one isolate showed increased germination in the presence of two of the four calcium salts. Germ tube elongation was not affected by calcium salts for four out of five isolates tested. There was significant variation among isolates and calcium salts on the growth of B. dothidea in liquid culture. Calcium chloride and calcium hydroxide enhanced the growth of three isolates and had no effect on the other three isolates. Calcium propionate inhibited the growth of four isolates and had no effect on the other two isolates. Calcium silicate inhibited the growth of one isolate and had no effect on the other five isolates.