sodium chloride and water

... for the a and b subunits within liganded tetrameric HbA modified by the interactions with sodium chloride and pyridoxal 5¢-phosphate are shown in Fig As evident, the rate constant (k¢) and the quantum ... Kt, for the last ligand binding step: Kt ¼ K1 Á K2 K1 þ K2 ð5Þ Here, K1 and K2 correspond to the affinity of O2 binding to the a and b subunits within the triliganded (monoliganded) tetramer (dimer), ... the triliganded HbA (Table 1, ), but only one in every 20 ligands leaves the a subunits (Table 1, ), and in every six ligands leaves the b subunits (Table 1, ) Using Eqns (3) and (4),...

Ngày tải lên: 16/03/2014, 14:20

... acetic acid w K and Jvater, was analyzed for the acid by titraltion v,ith standard sodium hydroxide, using ; phenolphthalein as the indicator I The residue, when it contained calcium t4 0chloride, was ... acetic acid I I I I I I I I This method of determining chloride in the 20 40 60 80 100 presence of sodium acetate and phenolphthaWEIGHT % WATER I N LIQUID lein indicator was found quite satisfactory ... INDUSTRIAL AND ENGINEERING CHEMISTRY Vol 42, No addition of calcium chloride tends t o reverse the relative volatility TABLE 111 SMOOTHED VAPOR-LIQUID EQUILIBRIUM BOIL- of acetic acid and water The...

Ngày tải lên: 05/05/2014, 08:42

... kidney to excrete a water load: (1) filtration and delivery of water (and electrolytes) to the diluting sites of the nephron; (2) active reabsorption of Na+ and Cl– without water in the thick ... impaired free water excretion, and eventual hyponatremia Sodium Balance Sodium is actively pumped out of cells by the Na+, K+-ATPase pump As a result, 85–90% of all Na+ is extracellular, and the ECF ... ensue and are manifest as edematous or hypovolemic states, respectively It is important to distinguish between disorders of osmoregulation and disorders of volume regulation since water and Na+...

Ngày tải lên: 06/07/2014, 15:21

... concentration and facilitated by insulin release and basal catecholamine levels Eventually, however, the excess K + is excreted in the urine (see below) The regulation of gastrointestinal K + handling ... filtered K+ is reabsorbed by the proximal convoluted tubule and loop of Henle Proximally, K + is reabsorbed passively with Na+ and water, whereas the luminal Na+-K+-2Cl– co-transporter mediates ... concentration and volume, increased distal flow rate can significantly enhance urinary K + output Finally, in severe K+ depletion, secretion of K+ is reduced and reabsorption in the cortical and medullary...

Ngày tải lên: 06/07/2014, 15:21

... disparities in permeability and the presence of transporters and active pumps The major ECF particles are Na+ and its accompanying anions Cl– and HCO3–, whereas K+ and organic phosphate esters ... state, water intake must equal water excretion Disorders of water homeostasis result in hypo- or hypernatremia Normal individuals have an obligate water loss consisting of urine, stool, and evaporation ... contribute to water shift across cell membranes and are known as ineffective osmoles Fluid movement between the intravascular and interstitial spaces occurs across the capillary wall and is determined...

Ngày tải lên: 06/07/2014, 15:21

... Renal Na+ and water loss Diuretics Osmotic diuresis Hypoaldosteronism Salt-wasting nephropathies C Renal water loss Diabetes insipidus (central or nephrogenic) II ECF volume normal or expanded A ... tubule and interstitial renal disorders are associated with Na+ wasting Excessive renal losses of Na+ and water may also occur during the diuretic phase of acute tubular necrosis (Chap 273) and ... can also impair tubular reabsorption of Na+ and water, leading to an osmotic or solute diuresis This often occurs in poorly controlled diabetes mellitus and in patients receiving high-protein hyperalimentation...

Ngày tải lên: 06/07/2014, 15:21

... exercise, or increased salt and water loss from skin, in the form of sweat, can be significant and lead to volume depletion The Na+ concentration of sweat is normally 20–50 mmol/L and decreases with profuse ... plasma volume and hypotension Hypotension is due to decreased venous return (preload) and diminished cardiac output; it triggers baroreceptors in the carotid sinus and aortic arch and leads to ... diaphoresis) Most symptoms are nonspecific and secondary to electrolyte imbalances and tissue hypoperfusion and include fatigue, weakness, muscle cramps, thirst, and postural dizziness More severe degrees...

Ngày tải lên: 06/07/2014, 15:21

... hypovolemic shock due to a profound sodium deficit and transcellular water shift Contraction of the ECF volume stimulates thirst and AVP secretion The increased water ingestion and impaired renal excretion ... hypotonic hyponatremia is due either to a primary water gain (and secondary Na+ loss) or a primary Na + loss (and secondary water gain) In the absence of water intake or hypotonic fluid replacement, ... solution can be absorbed and result in a dilutional hyponatremia The metabolism of sorbitol and glycine to CO2 and water may lead to hypotonicity if the accumulated fluid and solutes are not rapidly...

Ngày tải lên: 06/07/2014, 15:21

... causes of SIADH include neuropsychiatric and pulmonary diseases, malignant tumors, major surgery (postoperative pain), and pharmacologic agents Severe pain and nausea are physiologic stimuli of ... volume depletion) and directly (cosecreted with corticotropinreleasing factor) The mechanisms by which hypothyroidism leads to hyponatremia include decreased cardiac output and GFR and increased ... function of the minimum urine osmolality achievable and the mandatory solute excretion Metabolism of a normal diet generates about 600 mosmol/d, and the minimum urine osmolality in humans is 50...

Ngày tải lên: 06/07/2014, 15:21

... concentration by restricting water intake and promoting water loss and (2) to correct the underlying disorder Mild asymptomatic hyponatremia is generally of little clinical significance and requires no treatment ... increased total body water that exceeds the increase in total body Na+ content Treatment should include restriction of Na+ and water intake, correction of hypokalemia, and promotion of water loss in ... mosmol/kg) Patients are typically normovolemic and have normal Na+ balance They tend to be mildly volume-expanded secondary to water retention and have a urine Na + excretion rate equal to intake...

Ngày tải lên: 06/07/2014, 15:21

... as a result of AVP suppression and a brisk water diuresis This can be prevented by administration of water or use of an AVP analogue to slow down the rate of free water excretion For further discussion, ... cases of hypernatremia result from the loss of water Since water is distributed between the ICF and the ECF in a 2:1 ratio, a given amount of solute-free water loss will result in a twofold greater ... is abnormal or access to water is limited The latter occurs in infants, the physically handicapped, and patients with impaired mental status; in the postoperative state; and in intubated patients...

Ngày tải lên: 06/07/2014, 15:21

... osmotic reabsorption of water This leads to water loss in excess of Na+ and K+, known as an osmotic diuresis The most frequent cause of an osmotic diuresis is hyperglycemia and glucosuria in poorly ... encodes the water channel protein whose membrane insertion is stimulated by AVP The causes of sporadic NDI are numerous and include drugs (especially lithium), hypercalcemia, hypokalemia, and conditions ... symptoms and signs include the absence or presence of thirst, diaphoresis, diarrhea, polyuria, and the features of ECF volume contraction The history should include a list of current and recent...

Ngày tải lên: 06/07/2014, 15:21

... defects in AVP secretion and action.[newpage] Hypernatremia: Treatment The therapeutic goals are to stop ongoing water loss by treating the underlying cause and to correct the water deficit The ECF ... The quantity of water required to correct the deficit can be calculated from the following equation: In hypernatremia due to water loss, total body water is approximately 50 and 40% of lean body ... treated with a low-Na+ diet and thiazide diuretics, as described above This induces mild volume depletion, which leads to enhanced proximal reabsorption of salt and water and decreased delivery to...

Ngày tải lên: 06/07/2014, 15:21

Ngày tải lên: 06/07/2014, 15:21

... region of the 11β-hydroxylase gene and the coding sequence of the aldosterone synthase gene Consequently, mineralocorticoid is synthesized in the zona fasciculata and regulated by corticotropin A ... with hyperreninemia result in secondary hyperaldosteronism and renal K + wasting High renin levels are commonly seen in both renovascular and malignant hypertension Renin-secreting tumors of the ... receptor and leads to the syndrome of apparent mineralocorticoid excess Drugs that inhibit the activity of 11β-HSDH include glycyrrhetinic acid, present in licorice, chewing tobacco, and carbenoxolone...

Ngày tải lên: 06/07/2014, 15:21

... volume contraction, and juxtaglomerular apparatus hyperplasia Finally, diuretic use and abuse are common causes of K+ depletion Carbonic anhydrase inhibitors, loop diuretics, and thiazides are ... (see above) is not uncommonly seen in K+ depletion and is manifest as polydipsia and polyuria Glucose intolerance may also occur with hypokalemia and has been attributed to either impaired insulin ... between individual patients, and their severity depends on the degree of hypokalemia Symptoms seldom occur unless the plasma K+ concentration is

Ngày tải lên: 06/07/2014, 15:21

... to treatment Potassium chloride is usually the preparation of choice and will promote more rapid correction of hypokalemia and metabolic alkalosis Potassium bicarbonate and citrate (metabolized ... administration of K+ should be used judiciously and requires close observation of the clinical manifestations of hypokalemia (electrocardiogram and neuromuscular examination) Hyperkalemia Etiology ... proper venipuncture technique is used and a plasma (not serum) K+ concentration is measured, it should be normal Intravascular hemolysis, tumor lysis syndrome, and rhabdomyolysis all lead to K+ release...

Ngày tải lên: 06/07/2014, 15:21

... hypoaldosteronism is a syndrome characterized by euvolemia or ECF volume expansion and suppressed renin and aldosterone levels (Chaps 336 and 338) This disorder is commonly seen in mild renal insufficiency, ... hyporeninemic hypoaldosteronism NSAIDs inhibit renin secretion and the synthesis of vasodilatory renal prostaglandins The resultant decrease in GFR and K + secretion is often manifest as hyperkalemia As ... excretion but may significantly contribute to hyperkalemia in protein-malnourished (low urea excretion) and ECF volume–contracted (decreased distal NaCl delivery) patients Decreased K+ secretion by the...

Ngày tải lên: 06/07/2014, 15:21

... cell disease, and diabetic nephropathy Gordon's syndrome is a rare condition characterized by hyperkalemia, metabolic acidosis, and a normal GFR These patients are usually volumeexpanded with suppressed ... excitability and is manifest as weakness, which may progress to flaccid paralysis and hypoventilation if the respiratory muscles are involved Hyperkalemia also inhibits renal ammoniagenesis and reabsorption ... hyperkalemia result in a prolonged PR interval and QRS duration, atrioventricular conduction delay, and loss of P waves Progressive widening of the QRS complex and merging with the T wave produces a...

Ngày tải lên: 06/07/2014, 15:21

... wasting, ECF volume contraction, and high renin and aldosterone levels In contrast, enhanced distal Cl– reabsorption is associated with volume expansion and suppressed renin and aldosterone secretion ... within 1–2 h and last for 4–6 h Sodium polystyrene sulfonate can also be administered as a retention enema consisting of 50 g of resin and 50 mL of 70% sorbitol mixed in 150 mL of tap water The ... weakness, and changes on the electrocardiogram Potentially fatal hyperkalemia rarely occurs unless the plasma K+ concentration exceeds 7.5 mmol/L and is usually associated with profound weakness and...

Ngày tải lên: 06/07/2014, 15:21