Calcium increases

PTH is the most important regulator of bone remodelling and calcium homeostasis. PTH is an 84-amino acid polypeptide and is secreted by the parathyroid glands in response to reductions in blood levels of ionised calcium. The primary physiological effect of PTH is to increase serum calcium. To this aim, PTH acts on the kidney to decrease urine calcium, increase mine phosphate, and increase the conversion of 25-OH-vitamin D to l,25-(OH)2-vitamin D. PTH acts on bone acutely to increase bone resorption and thus release skeletal calcium into the circulation. However, due to the coupling of bone resorption and bone formation, the longer-term effect of increased PTH secretion is to increase both bone resorption and bone formation. 

Although in in vivo circumstances an intracellular free calcium increase apparently acts as the primary modulator of contraction, it can be bypassed in highly permeabilized smooth muscle preparations where the active subunit of MLCK can be introduced to phosphorylate myosin and induce contraction. The MLCK catalyzed phosphorylation of serine-19 is seen as the necessary event in the activation of smooth muscle myosin to form crossbridges. Thus, the rising phase of force during an isometric smooth muscle contraction follows an increase in the degree of phosphorylation of myosin, and that in turn follows the transient rise of (a) cytosolic free Ca, (b) Ca-calmodulin complexes, and (c) the active form of MLCK. The regulation of the intracellular calcium is discussed below. The dynam-... 

Because of their strategic localization, astrocytes play a crucial role in maintaining the extracellular ionic homeostasis, provide energetic metabolites to neurons and remove excess of neurotransmitter in schedule with synaptic activity. In addition, the strategic location of astrocytes allows them to carefully monitor and control the level of synaptic activity. Indeed, number of papers during the last 15 years have shown that cultured astrocytes can respond to a variety of neurotransmitters with a variety of different patterns of intracellular calcium increases (Verkhratsky et al. 1998). Later on, studies performed in intact tissue preparations (acute brain slices) further established that the plasma membrane receptors can sense external inputs (such as the spillover of neurotransmitters during intense synaptic activity) and transduce them as intracellular calcium elevations, mostly via release of calcium from internal stores (Dani et al. 1992 Murphy et al. 1993 Porter and McCarthy... 

Eventually, after 40-50 min of oxidant stress, intracellular calcium increased. These changes were irreversible when cells were reperfused with control buffer at the end of the protocol. Redrawn with permission from Burton et al. (1990). 

Fromm and Spanswick [79] found that electrical stimulation of a plant is followed by ion shifts which are most striking in the phloem cells. While their content of potassium and chloride was diminished after stimulation, the amount of cytoplasmic calcium increased slightly (Table 1). These displacements lead to the conclusion that Ca + influx as well as and CP efflux are involved in the propagation of action potentials. The main difference between propagation of action potentials in animals and plants is that in an axon there is the K /Na transmembrane transport but in phloem cells the K /Ca channels are involved in this process [Fig. 22(b)]. 

Fasting ultrafilterable calcium increased and serum bone alkaline phosphatase isoenzyme levels decreased, but only in those with calcium intakes < 600mg/d. 

Calcium Pig Lead in tissues at low levels of dietary calcium Increased absorption of lead with low dietary calcium Hsu et al. 1975... 

Decrease blood calcium Increase blood calcium decrease blood phosphate activation of vitamin D 3 "Fight-or-flight" response reinforces effects of the sympathetic nervous system Reabsorption of sodium excretion of potassium... 

In the absence of ATP, myosin crossbridges are unable to release the actin. As a result, the sarcomeres, and therefore the muscle, remain contracted. This phenomenon is referred to as rigor mortis. Following death, the concentration of intracellular calcium increases. This calcium allows the... 

In bean hypocotyl, the increase of resistance in the course of ripening was found to be accompanied292 by a decrease in the meth-oxyl content from 0.5 to 0.2%, while the content of calcium increased from 0.38 to 1.92%. An increased content of calcium was observed in a resistant variety of cucumber hypocotyl.293 These results suggest that one of the protective mechanisms of the plant against infection is the conversion of pectic acid into calcium pectate, which is resistant to the action of pectic enzymes. 

Calcium should be ingested in adequate amounts to prevent secondary hyperparathyroidism and bone destruction. Although calcium increases BMD, fracture prevention is minimal. It should be combined with vitamin D and osteoporosis medications when needed. 

Bhalla RC, Toth KF, Bhatty RA, Thompson LP, Sharma RV (1997) Estrogen reduces proliferation and agonist-induced calcium increase in coronary artery smooth muscle cells. Am J Physiol 272 H 1996-2003... 

The immunotoxicology of metals in fishes has been reviewed elsewhere [74-76, 45], Overall, the immune systems of fishes are highly sensitive to metals, although the effects are not always suppression of immune functions. Burnett [76] demonstrated that low levels of metals increased intracellular calcium, increased protein phosphorylation, and stimulated lymphocyte proliferation in fish. Since most metals are toxic to both the nervous system and the immune system, a neuroendocrine-immune link to immuno-toxicity from metal exposure is likely. 

The content of nitrogen in fallen leaves as a major shedding component is about twice as much as that in the needles of coniferous trees. The total sum of ash elements in the leaves accounts for 3-5%, average about 4% on dry weight basis. Accordingly, the concentration of calcium increases from 0.5 to 4.0%, potassium from 0.15 to 2.0% and silicon with a wide variation. The row of nutrient uptake is as the following ... 

For HS-I, with calcium intakes of about 1100 mg/day, no difference was observed in either apparent absorption or balance of calcium over the last 10 of 15 days when the phytate intake was 0.2 or 2.0 g/day. The molar ratio of phytate/calcium was either 0.01 or 0.1 in HS-I. In HS-II the calcium intake was lower, about 740 mg/day, but the same across three levels of phytic acid, 0.5, 1.7 and 2.9 g/day. The phytate/calcium molar ratios were 0.04, 0.14 and 0.24. Apparent absorption of calcium for the 15-day diet treatment period became progressively less as the molar ratio of phytate/calcium increased, to the extent that 6 of 12 individuals excreted more calcium in the feces than they consumed when the mean ratio was 0.24. About 200 mg of calcium was excreted daily in the urine by... 

As anticipated, arginine infusion caused a large (221 percent) increase in calcium excretion in sham-operated animals. Parathyroidectomy had no effect on the calciuric response to arginine uri-ary calcium increases in PTX control and arginine-infused animals were 299 and 302 percent respectively. These results persisted when data were corrected for differences in GFR. The data illustrate that neither PTH activity nor secretion is involved in insulin impairment of renal calcium transport. 

The effects of varying either the calcium or phosphorus level in conjunction with a high beef meal on the urinary calcium excretion of men are shown in Table IV. Urinary calcium excretion (total and ionized) was significantly elevated (P < 0.005) when the high protein beef meal contained 466 mg rather than 166 mg calcium. Increasing the phosphorus level from 308 mg to 700 mg in the high beef meal reduced both total and ionized calcium excretion in the urine, but the response was not statistically significant. Serum levels of calcium (ionized and total) and phosphorus were within normal limits and were unaffected by any of the dietary treatments. 

Table VII shows the urinary excretion of ionized calcium following the various liquid meals. Urinary excretion of ionized calcium increased during the first hour after ingestion of the basal meal. The excretion rate then decreased and approached fasting levels by 2 hours post-meal. Although the addition of 15 g of protein as cottage cheese increased the quantity of ionized calcium...

A representative example of the effect of phosphorus given as sodium glycerophosphate is shown on Table I. Increasing the phosphorus Intake from 800 mg to 2000 mg per day during a normal calcium Intake of approximately 850 mg per day resulted in a decrease of the urinary calcium from 301 mg to 179 mg per day, the stool calcium increased slightly and the calcium balance became somewhat more positive. 

Table I shows that the addition of 140 mg of zinc as zinc sulfate per day, during a low calcium Intake of 230 mg/day, decreased the urinary calcium, Increased the fecal calcium and the calcium balance remained unchanged. In nine patients studied during a low calcium Intake, the Intestinal absorption of calcium decreased significantly during the high zinc Intake, the absorption values averaging 61 + 6,6% In the control study and 39 + 4,6% during zinc supplementation, However, the decrease In calcium absorption was abolished...

Endothelins are a family of vasoactive peptides secreted by endothelial cells. The three major endothelin peptides are all composed of 21 amino acids. Endothelins are the most potent vasoconstrictors known. Contraction of vascular smooth muscle in response to endothelin is associated with an increase in intracellular calcium. Increases in endothelin levels have been reported in patients with vasospastic, hypoxic, and ischemic diseases. The two identified isoforms of endothelin receptors have differing affinity for the three endothelin peptides. Selective and nonselective endothelin receptor antagonists are in development for potential use in the treatment of hypertension and other disorders associated with increased vascular resistance. 

Net Serum calcium increased, serum Serum calcium and phosphate both increased Decreased serum phosphate... 

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