Thiazides and bone

The Incidence of Severe Hypercalcaemia-Induced Mental Status Changes in Patients Treated with Antibiotic-Loaded Calcium Sulphate Depot for Orthopaedic Infections

Local application of antibiotics with calcium-containing carrier materials (CCCM) might deliver large quantities of calcium, with some cases of hypercalcaemia reported. The incidence of symptomatic hypercalcaemia was estimated retrospectively in a consecutive, prospective series of patients treated between 10/2006 and 02/2019 with antibiotic-loaded CCCM for various orthopaedic infections. Risk factors were analysed. In the study period, 215 CCCM applications were performed. Two patients (0.9%) developed symptomatic hypercalcaemia. In one case, hypercalcaemia occurred 14 days after a second CCCM application during a staged septic hip revision. In the other case, hypercalcaemia became symptomatic six days after application of vancomycin-loaded CCCM in a component-retaining septic revision hip arthroplasty. In both cases, hypercalcemia was not imputable solely to the CCCM. Prolonged immobilization, renal impairment and other specific risk factors were present. Implantation of a CCCM for local application of antibiotics exposes the patient to large quantities of calcium during dissolution. This might induce symptomatic hypercalcaemia, a potentially life-threatening complication. The observed incidence of symptomatic hypercalcaemia remained rare (<1%). In some patients, compensatory mechanisms might be overwhelmed in the presence of other risk factors. Postoperative monitoring of calcaemia as well as elimination of risk factors is mandatory for all patients treated with CCCM.

Applications of nuclear quadrupole resonance spectroscopy in drug development

In this review, fundamentals of nuclear quadrupole resonance (NQR) spectroscopy are briefly outlined. Examples of its applications in drug development are discussed to demonstrate that the NQR method is a sophisticated, non-destructive and valuable analytical technique for studying pharmaceuticals, providing effective assistance at the two main steps of drug development: the physical and chemical characterization of the active pharmaceutical ingredients (API) at the analytical step and API development. This review covers different aspects of the use of NQR spectroscopy for drug development and analysis and illustrates the power and versatility of this method in the determination of impurities, polymorphic forms, the drug's structure and conformation, characterization of the interactions between the drug and ligands, search for analogs (second- or third-generation drugs) and the drug's thermal stability. Lastly, NQR advantages and restrictions in the aspect of application in drug development studies are summarized.

Diuretics in clinical practice. Part II: electrolyte and acid-base disorders complicating diuretic therapy

IMPORTANCE OF THE FIELD

As with all potent therapeutic agents, the use of diuretic compounds has been linked with several adverse effects that may reduce quality of life and patient compliance and, in some cases, may be associated with considerable morbidity and mortality. Among the various types of adverse effects, disturbances of electrolyte and acid-base balance are perhaps the most common, and some of them are the aetiological factors of other side effects (i.e., hypokalaemia causing ventricular arrhythmias or glucose intolerance). The mechanism and site of action and, therefore, the pharmacological effects of each diuretic class largely determine the specific electrolyte or acid-base abnormalities that will accompany the use of each diuretic agent.

AREAS COVERED IN THE REVIEW

This article reviews the major electrolyte disturbances (hypokalaemia, hyperkalaemia, hyponatraemia, disorders of magnesium and calcium balance), as well as the acid-base abnormalities complicating the use of the various diuretic agents.

WHAT THE READER WILL GAIN

The reader will gain insights into the pathogenesis of the diuretic-induced electrolyte and acid-base disorders together with considerations for their prevention and treatment.

TAKE HOME MESSAGE

Knowledge of the pharmacologic properties of each diuretic class and appropriate monitoring of patients under diuretic treatment represent the most important strategies to prevent the development of diuretic-related adverse events and their consequences.

Calcium-alkali syndrome-like symptoms manifested by daily alphacalcidol and thiazide

A 73-year-old man was admitted with complaints of a 2-month history of generalized weakness and numbness. Laboratory examination revealed hypercalcemia, metabolic alkalosis, and kidney injury, similar to the traditional milk-alkali syndrome. The clinical history and the response to therapy indicated that alphacalcidol and thiazide taken daily were the cause. Recently, it has been recommended the term "milk-alkali syndrome" be replaced by "calcium-alkali syndrome", which broadens the definition of the condition. This case suggests that the calcium-alkali syndrome can occur without calcium and alkali, but rather with alphacalcidol and a thiazide diuretic.

Milk-alkali syndrome

Milk-alkali syndrome (MAS) consists of hypercalcemia, various degrees of renal failure, and metabolic alkalosis due to ingestion of large amounts of calcium and absorbable alkali. This syndrome was first identified after medical treatment of peptic ulcer disease with milk and alkali was widely adopted at the beginning of the 20th century. With the introduction of histamine2 blockers and proton pump inhibitors, the occurrence of MAS became rare; however, a resurgence of MAS has been witnessed because of the wide availability and increasing use of calcium carbonate, mostly for osteoporosis prevention. The aim of this review was to determine the incidence, pathogenesis, histologic findings, diagnosis, and clinical course of MAS. A MEDLINE search was performed with the keyword milk-alkali syndrome using the PubMed search engine. All relevant English language articles were reviewed. The exact pathomechanism of MAS remains uncertain, but a unique interplay between hypercalcemia and alkalosis in the kidneys seems to lead to a self-reinforcing cycle, resulting in the clinical picture of MAS. Treatment is supportive and involves hydration and withdrawal of the offending agents. Physicians and the public need to be aware of the potential adverse effects of ingesting excessive amounts of calcium carbonate.

Milk-alkali syndrome

Milk-alkali syndrome (MAS) consists of hypercalcemia, various degrees of renal failure, and metabolic alkalosis due to ingestion of large amounts of calcium and absorbable alkali. This syndrome was first identified after medical treatment of peptic ulcer disease with milk and alkali was widely adopted at the beginning of the 20th century. With the introduction of histamine2 blockers and proton pump inhibitors, the occurrence of MAS became rare; however, a resurgence of MAS has been witnessed because of the wide availability and increasing use of calcium carbonate, mostly for osteoporosis prevention. The aim of this review was to determine the incidence, pathogenesis, histologic findings, diagnosis, and clinical course of MAS. A MEDLINE search was performed with the keyword milk-alkali syndrome using the PubMed search engine. All relevant English language articles were reviewed. The exact pathomechanism of MAS remains uncertain, but a unique interplay between hypercalcemia and alkalosis in the kidneys seems to lead to a self-reinforcing cycle, resulting in the clinical picture of MAS. Treatment is supportive and involves hydration and withdrawal of the offending agents. Physicians and the public need to be aware of the potential adverse effects of ingesting excessive amounts of calcium carbonate.

Les hypercalciuries

The frequency of hypercalciuria is increasing in western countries with an incidence of nephrolithiasis which can reach 13%. Hypercalciuria appears as an alteration of the calcium transport system (kidney, bowel, bone) which is regulated by calcitriol and parathormone. The aim of this review was to screen etiologies of hypercalciuria taking into account recent genetic advances (calcium epithelial channel and calcium sensing receptor). Hypercalciuria may be favored by nutritional causes (diet rich in calcium, sodium, carbohydrates, proteins, poor in phosphates and potassium). It may also be related to an increase in calcium absorption (vitamin D excess, primary hyperparathyroidism, sarcoidosis, lymphoma, estrogens, and certain genetic causes), an increase in osteoresorption (bone metastasis, myeloma, Paget, hyperthyroidism, immobilization, hypercortisolism and corticosteroid therapy), or a decrease of kidney tubular resorption (diuretics, Cacci and Ricci, acromegally, Bartter, familial dominant hypocalcemia, Fanconi, Dent, familial hypomagnesemia-hypercalciuria syndrome, type 1 distal tubular acidosis, pseudohypoaldosteronism, diabetes). If no cause is identified, persistence of hypercalciuria after instituting a correct diet is defined as idiopathic hypercalciuria. Treatment of the cause is essential in secondary hypercalciuria, in addition to diet (low sodium intake, normocalcic diet, hydration), associated with thiazide diuretics and biphosphonates if necessary.

Nuclear Quadrupole Resonance spectroscopy in studies of biologically active molecular systems—a review

The main idea of this work was to give an overview of the NQR capabilities in the search for a correlation between electronic structure and biological activity of certain compounds, mainly drugs. A correlation between the parameters characterising biological activity and the NQR spectral parameters describing chemical properties of a given compound, permits drawing conclusions on biological effectiveness of compounds from a certain group. The quadrupole coupling constants, which are very well correlated with atomic charges, can be treated as descriptors in QSAR. The information inferred from NQR study on local electron density distribution together with analysis of charge distribution, provides excellent means for determination of reactive sites and hence, can indicate possible promising directions to be followed in drugs design.

Thiazide-sensitive NaCl-cotransporter in the Intestine

Thiazides, such as hydrochlorothiazide (HCTZ), are used to control blood pressure and to reduce renal calcium excretion. These effects are a result of interactions with the NaCl-cotransporter (NCC). This is demonstrated by the fact that mutations within the NCC protein lead to salt-resistant hypotension and hypocalciuria, paralleled by an increase in bone mineral density. These symptoms are also known as Gitelman syndrome. It has become increasingly evident that the effect of HCTZ on blood pressure and calcium homeostasis cannot be attributed exclusively to kidney functions, where the primary action of HCTZ on NCC is postulated to occur. We demonstrated the presence of the NCC transporter in the rat small intestine (ileum and jejunum) and human HT-29 cells, by using reverse transcription-PCR, Northern blot, Western blot, and immunofluorescence. Furthermore, we show that HCTZ modulates Ca(2+) uptake by intestinal cells, while affecting the electrical parameters of the cellular membrane, thus suggesting a functional interaction between NCC and the epithelial voltage-dependent calcium channel. The experiments presented here support the hypothesis of a direct involvement of the intestinal cells in the interaction between HCTZ and NaCl, as well as calcium homeostasis.

Molecular Physiology and Pathophysiology of Electroneutral Cation-Chloride Cotransporters

Electroneutral cation-Cl−cotransporters compose a family of solute carriers in which cation (Na+or K+) movement through the plasma membrane is always accompanied by Cl−in a 1:1 stoichiometry. Seven well-characterized members include one gene encoding the thiazide-sensitive Na+−Cl−cotransporter, two genes encoding loop diuretic-sensitive Na+−K+−2Cl−cotransporters, and four genes encoding K+−Cl−cotransporters. These membrane proteins are involved in several physiological activities including transepithelial ion absorption and secretion, cell volume regulation, and setting intracellular Cl−concentration below or above its electrochemical potential equilibrium. In addition, members of this family play an important role in cardiovascular and neuronal pharmacology and pathophysiology. Some of these cotransporters serve as targets for loop diuretics and thiazide-type diuretics, which are among the most commonly prescribed drugs in the world, and inactivating mutations of three members of the family cause inherited diseases such as Bartter's, Gitelman's, and Anderman's diseases. Major advances have been made in the past decade as consequences of molecular identification of all members in this family. This work is a comprehensive review of the knowledge that has evolved in this area and includes molecular biology of each gene, functional properties of identified cotransporters, structure-function relationships, and physiological and pathophysiological roles of each cotransporter.