Calcium disorders

Other Calcium Disorders. In addition to hypocalcemia, tremors, osteoporosis, and muscle spasms (tetary), calcium deficiency can lead to rickets, osteomalacia, and possibly heart disease. These, as well as Paget s disease, can also result from faulty utilization of calcium. Calcium excess can lead to excess secretion of calcitonin, possible calcification of soft tissues, and kidney stones when combined with magnesium deficiency. 

Thode J, Juul-Jorgensen B, Bhatia HM, Kjaerulf-Nielsen M, Bartels PD, Fogh-Andersen N, Siggaard-Andersen O. Comparison of serum total calcium, albumin-corrected total calcium and ionized calcium in 1213 patients with suspected calcium disorders. Scand J Clin Lab Invest 1989 49 217-23. 

BIOCHEMISTRY TESTING IN CALCIUM DISORDERS OR BONE DISEASE... 

The role of the routine biochemistry laboratory in diagnosis and treatment of patients w ith calcium disorders and bone disease is to provide measurements of calcium, albumin, phosphate and alkaline phosphatiisc in a scrum specimen as first line tests. Follow-up tests which may be requested include ... 

If the semm calcium is greater than 11 mg/dL, the patient has nephrolithiasis, or the serum creatinine is elevated, dmg therapy is usually required. The drug of choice is prednisone at an initial daily dose of 20 to 40 mg/day (183). Corticosteroids cause a rapid decline in serum calcium within 5 days and in urinary calcium excretion in 7 to 10 days (183). Failure of the serum calcium to normalize within two weeks on this corticosteroid regimen should alert the clinician to an alternate or coexisting disorder such as hyperparathyroidism, lymphoma, carcinoma, and myeloma (183). Once the calcium disorder is brought under control, the corticosteroid dose can be lowered over four to six weeks (183). The serum calcium and urinary calcium excretion rate should be closely monitored. If the patient develops intolerable corticosteroid side effects or fails to respond, chloroquine (184), hydroxychloroquine (185), and ketoco-nizole (186) have been used successfully. 

Other agents are also used for the treatment of manic-depressive disorders based on preliminary clinical results (177). The antiepileptic carbamazepine [298-46-4] has been reported in some clinical studies to be therapeutically beneficial in mild-to-moderate manic depression. Carbamazepine treatment is used especially in bipolar patients intolerant to lithium or nonresponders. A majority of Hthium-resistant, rapidly cycling manic-depressive patients were reported in one study to improve on carbamazepine (178). Carbamazepine blocks noradrenaline reuptake and inhibits noradrenaline exocytosis. The main adverse events are those found commonly with antiepileptics, ie, vigilance problems, nystagmus, ataxia, and anemia, in addition to nausea, diarrhea, or constipation. Carbamazepine can be used in combination with lithium. Several clinical studies report that the calcium channel blocker verapamil [52-53-9] registered for angina pectoris and supraventricular arrhythmias, may also be effective in the treatment of acute mania. Its use as a mood stabilizer may be unrelated to its calcium-blocking properties. Verapamil also decreases the activity of several neurotransmitters. Severe manic depression is often treated with antipsychotics or benzodiazepine anxiolytics. 

Progress in deducing more structural details of these fibers has instead been achieved using NMR, electron microscopy and electron diffraction. These studies reveal that the fibers contain small microcrystals of ordered regions of the polypeptide chains interspersed in a matrix of less ordered or disordered regions of the chains (Eigure 14.9). The microcrystals comprise about 30% of the protein in the fibers, are arranged in p sheets, are 70 to 100 nanometers in size, and contain trace amounts of calcium ions. It is not yet established if the p sheets are planar or twisted as proposed for the amyloid fibril discussed in the previous section. 

Zinc and cadmium have an oxidation number of +2 in all their compounds. Zinc is an essential element for human health. It is present in many enzymes and plays a role in the expression of DNA and in growth. Zinc is toxic only in very-high amounts. However, cadmium is a deadly poison that disrupts metabolism by-substituting for other essential metals in the body such as zinc and calcium, leading to soft bones and to kidney and lung disorders. 

The low-temperature (/1-)AE3(BN2)2 phases exhibit two distinct structures for AE = Ca and Sr that can be derived from the cation disordering in their respective high-temperature phases. For / -Ca3(BN2)2 an orthorhombic (Cmca) superstructure of the cubic cell with fi-a bo a, Cq ly l a was obtained, in which the former 8f sites are occupied by seven calcium ions in an ordered fashion. In contrast, the structure of / -Sr3(BN2)2 is simply the result of a transition from a cubic body-centered (Im3m) into a primitive structure (Pm3m), in which the former 2 a position (0, 0, 0 1/2, 1/2, 1/2) is split into two independent positions, of which only one is occupied by strontium (Fig. 8.6). 

Anion Interstitials The other mechanism by which a cation of higher charge may substitute for one of lower charge creates interstitial anions. This mechanism appears to be favored by the fluorite structure in certain cases. For example, calcium fluoride can dissolve small amounts of yttrium fluoride. The total number of cations remains constant with Ca +, ions disordered over the calcium sites. To retain electroneutrality, fluoride interstitials are created to give the solid solution formula... 

It has been revealed that cannabinoids exhibit neuroprotectant activities in both in vitro and in vivo models [249]. The neuroprotective effects are mainly based on regulation of transmitter release, modulation of calcium homeostasis, anti-oxidant properties and modulation of immune responses. A number of neurological disorders, including brain trauma, cerebral ischaemia, Parkinson s disease and Alzheimer s disease represent possible therapeutic areas for cannabinoids with neuroprotective properties. Cannabinoids are also suggested to have potential against glaucoma due to their neuroprotective nature and lowering of intraocular pressure [250]. 

Uncontrolled hypertension Valvular disorders function sympathomi meti cs) Offending medications (NSAIDs, COX-2 inhibitors, steroids, lithium, (i-blockers, calcium channel blockers, anti-arrhythmics, alcohol, thiazolidinediones)... 

Any time an ABG is analyzed it is wise to concurrently inspect the serum chemistry values to calculate the anion gap. The body does not generate an anion gap to compensate for a primary disorder. As such, if the calculated anion gap exceeds 12 mEq/L (mmol/L) there is a primary metabolic acidosis regardless of the pH or the serum HC03 concentration. The anion gap may be artificially lowered by decreased serum albumin, multiple myeloma, lithium intoxication, or a profound increase in the serum potassium, calcium, or magnesium. 

Aluminium toxicity is the likely cause of three human disorders arising from long-term haemodialysis vitamin D-resistant osteomalacia, iron adequate microcytic anaemia, and dialysis dementia (Martin, 1994). The first of these conditions is consistent with interference with calcium deposition into bone, and the accumulation of aluminium in the bone matrix. 

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