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Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The acid-base status in the toad Bufo viridis was assessed on blood samples taken through a chronical cannula from unrestrained animals. Blood gases and the pH were very constant in animals which were kept either under control conditions (free access to tap water) or immersed in shallow water. pH was 7.646 +/- 0.032 (mean +/- SEM) in 14 control toads at 26 degrees C. PCO2 was 13.1 +/- 1.2 mm Hg and [HCO3-] was 17.0 +/- 0.7 mmol/l at the same temperature. pH and PCO2 were independent of the hematocrit and the haemoglobin in the blood. Diamox induced a characteristic metabolic acidosis which is apprently the result of the inhibition of carbonic anhydrase both in the kidney and in the skin. The results are discussed in relation to the role of the kidney and the skin in regulating the acid-base balance in the toad.
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PMID:Acid-base status in the toad Bufo viridis in vivo. 677 53

Calcium (Ca) metabolism was compared in 2 groups of patients with chronic interstitial nephritis: in 21 patients (AAN-group) nephropathy was due to exposure for 5 to 50 years (mean 21.1) to phenacetin containing analgesics, whereas in 21 other patients (controls) it was due to exposure for 1 to 80 years (mean 21.4) (NS) to other causes. Patients were followed for 2.5 +/- 0.6 and 1.6 +/- 0.6 years respectively (mean +/- SEM) (NS). Blood Ca, P, protein, creatinine, alkaline phosphatase, parathyroid hormone (PTH), 25-hydroxyvitamin D (25-OH-D), together with arterial acid-base status and urinary excretion rate of Ca, P and creatinine were measured serially. For each patient the results were averaged for 2 degrees of renal failure, i.e. for creatinine levels below and above 400 mumol/l (logarithmic mean). Results were included only when P was maintained between 0.7 and 1.9 mmol/l. The range of creatinine levels studied was 95 to 1600 mumol/l. No differences were found between the 2 groups with respect to creatinine clearance, blood, P, protein, arterial pH and urinary excretion rates of Ca and P. There was a trend for blood HCO3 to be lower in the AAN group. Mean plasma Ca was significantly lower, and PTH was significantly higher, in the AAN than in the control group at both degrees of renal failure; mean plasma alkaline phosphatase activity was also significantly higher in the AAN group, but at severe degrees of renal failure only. Significant correlations were observed between individual values of both Ca and PTH (r = -0.747) and PTH and alkaline phosphatase (r = 0.603). The degree of hypocalcemia and of hyperparathyroidism was not related to the plasma level of 25-OH-D. It is concluded that at comparable degrees and duration of renal failure patients with AAN, when compared with patients with interstitial nephritis of other origins, have lower blood Ca and consequently higher PTH levels and alkaline phosphatase activities, suggesting more severe osteodystrophy.
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PMID:[Particularly severe calcium metabolic disorder in nephropathy from analgesic abuse]. 717 76

Various stones were examined by a combined electron microscopy. Morphological parameters of calcium oxalates and phosphates, struvite, urates, cystine, gypsum, siliceous deposits in urinary, prostatic and salivary calculi, and calcium carbonate in gallstones were defined. Study also disclosed that stones frequently contain organic crystals in addition to the organic matrix. Membranous cell debris was observed in the nuclei of small stones and were believed to be common nidus of various stones. In view of a very limited number of crystals occurring in human stones, which differ obviously in their habits and growth patterns, an expeditious identification of stone components is possible by scanning electron microscopy. SEM with x-ray analysis is a powerful tool for research and diagnosis of various stones. It is most suitable for the study of surface phenomena, such as crystal growth, detection of phenomena, such as crystal growth, detection of organic matrix and minor components of the stones, and is a wide open field for a further study.
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PMID:The stones. 718 45

To elucidate the mechanism responsible for the establishment of steady state pH at zero net flux (pH infinity) in proximal convoluted tubules, luminal pH was recorded continuously with antimony microelectrodes under three experimental conditions. First: luminal pH in stationary droplets was allowed to reach pH infinity (6.76 +/- 0.07) and then carbonic anhydrase inhibitor benzolamide (3 x 10(-3) mol/l) was superfused on the kidney surface. Following application of benzolamide, luminal pH decreased within seconds (delta pH = -0.27 +/- 0.03 SEM). Second: tubule segments were perfused continuously with MES-buffer containing solution set to a pH of 6.1. Some 1--2 mm distal to the perfusion pipette luminal pH was recorded and was 6.5 +/- 0.04. After superfusion of benzolamide (3 x 10(-3) mol/l) pH decreased (delta pH = -0.15 +/- 0.03). Third: pH in stationary droplets was again allowed to reach PH infinity (6.69 +/- 0.01) and bicarbonate and CO2- free solution (5 mmol/l phosphate set to a pH of 7.4) was microinfused into the adjacent peritubular capillary. Luminal pH again decreased almost immediately (delta pH = -0.23 +/- 0.02). The data are interpreted as evidence for a bicarbonate leak. In a fourth series of experiments, segments of proximal tubules were perfused under benzolamide (0.4 x 10(-6) mol/min) with solutions initially free of bicarbonate or other buffers. In the collected fluid, bicarbonate was determined by a micro-Astrup method. A significant increase of luminal bicarbonate concentration (r = 0.88) indicates a permeability of 0.98 +/- 0.14 x 10(-6) cm2/s of the tubular wall for bicarbonate. Since bicarbonate eventually increases more than 3-fold the equilibrium concentration, collected bicarbonate could not have been formed by H2CO3 or CO2. Bicarbonate enters the luminal fluid and reacts with secreted hydrogen ions to forms carbonic acid. It, therefore, buffers secreted hydrogen ions and increases luminal pH at or below steady state. Inhibition of carbonic anhydrase and lowering of peritubular bicarbonate thus lower pH infinity.
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PMID:Evidence for a bicarbonate leak in the proximal tubule of the rat kidney. 719 58

In a continuing prospective randomized study in a series of patients in the postoperative state, the rate of albumin synthesis was measured using the 14C carbonate technique. The majority of the patients studied were subjected to partial or total colectomy, and each patient was randomized to receive a hypocaloric intravenous regimen consisting of 3.5% amino acids (essential and nonessential) or 3.5% amino acids with 2.5% glucose. A mean (+/- SEM) of 75.7 +/- 2.7 gm/day of amino acids was given to the seven patients in the amino acid group. A mean of 74.0 +/- 5.9 gm/day of amino acids and 52.8 +/- 4.2 gm/day of glucose was infused in the group of five patients given amino acids with glucose. The albumin synthetic rate (mg/kg/day) measured on the fourth day after operation in the amino acid alone group was 233.9 +/- 27.9 as compared to 204.1 +/- 24.4 in the group given amino acids with glucose (P = NS). The urea synthesis rates (mg/kg/day) in the two groups were 334.2 +/- 47.8 and 250.3 +/- 27.5, respectively, and the net Kjeldahl nitrogen balances (grams per day) were -4.98 +/- 1.92 and -2.68 +/- 1.49, respectively. We conclude that infused amino acids promote the synthesis of albumin equally effectively in the presence or absence of a small amount of added glucose. Glucose may reduce slightly the pool of amino nitrogen available for albumin and urea synthesis by diverting some of the infused amino acids from protein synthesis by the liver to muscle.
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PMID:Albumin synthesis and nitrogen balance in postoperative patients. 736 Dec 72

The cystic fibrosis transmembrane conductance regulator (CFTR) is an epithelial Cl- channel regulated by protein kinase A. The most common mutation in cystic fibrosis (CF), deletion of Phe-508 (delta F508-CFTR), reduces Cl- secretion, but the fatal consequences of CF have been difficult to rationalize solely in terms of this defect. The aim of this study was to determine the role of CFTR in HCO3- transport across cell membranes. HCO3- permeability was assessed from measurements of intracellular pH [pHi; from spectrofluorimetry of the pH-sensitive dye 2',7'-bis(2-carboxyethyl)-5-(and -6)carboxyfluorescein] and of channel activity (patch clamp; cell attached and isolated, inside-out patches) on NIH 3T3 fibroblasts and C127 mammary epithelial cells transfected with wild-type CFTR (WT-CFTR) or delta F508-CFTR, and also on mock-transfected cells. When WT-CFTR-transfected cells were acidified (pulsed with NH4Cl) and incubated in Na(+)-free (N-methyl-D-glucamine substitution) solutions (to block Na(+)-dependent pHi regulatory mechanisms), pHi remained acidic (pH approximately 6.5) until the cells were treated with 20 microM forskolin (increases cellular [cAMP]); pHi then increased toward (but not completely to) control level (pHi 7.2) at a rate of 0.055 pH unit/min. Forskolin had no effect on rate of pHi recovery in delta F508 and mock-transfected cells. This Na(+)-independent, forskolin-dependent pHi recovery was not observed in HCO3-/CO2-free medium. Forskolin-treated WT-CFTR-transfected (but not delta F508-CFTR or mock-transfected) cells in Cl(-)-containing, HCO3(-)-free solutions showed Cl- channels with a linear I/V relationship and a conductance of 10.4 +/- 0.5 pS in symmetrical 150 mM Cl-. When channels were incubated with different [Cl-] and [HCO3-] on the inside and outside, the Cl-/HCO3- permeability ratio (determined from reversal potentials of I/V curves) was 3.8 +/- 1.0 (mean +/- SEM; n = 9); the ratio of conductances was 3.9 +/- 0.5 (at 150 mM Cl- and 127 mM HCO3-. We conclude that in acidified cells the WT-CFTR functions as a base loader by allowing a cAMP-dependent influx of HCO3- through channels that conduct HCO3- about one-quarter as efficiently as it conducts Cl-. Under physiological conditions, the electrochemical gradients for both Cl- and HCO3- are directed outward, so CFTR likely contributes to the epithelial secretion of both ions. HCO3- secretion may be important for controlling pH of the luminal, but probably not the cytoplasmic, fluid in CFTR-containing epithelia. In CF, a decreased secretion of HCO3- may lead to decreased pH of the luminal fluid.
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PMID:Bicarbonate conductance and pH regulatory capability of cystic fibrosis transmembrane conductance regulator. 751 98

The effect of calcium supplementation on secondary hyperparathyroidism of old age depends on the intestinal absorption of the calcium preparation used. In order to test the bioavailability and clinical usefulness of a new calcium preparation, heated oyster shell-seaweed calcium (HOSS Ca), a randomized, prospective, double-blind comparison of HOSS Ca, calcium carbonate and placebo was carried out in 58 hospitalized women with a mean age of 82. Group A received 900 mg Ca/day Ca as HOSS Ca, group B 900 mg Ca/day as CaCO3 and group C placebo in addition to the basic hospital diet containing approximately 600 mg Ca/day. After 18 months, lumbar spine bone mineral density (BMD) measured by DPX was 106.1 +/- 3.5% (mean +/- SEM) of the pretrial basal value in group A, 99.8 +/- 3.8% in group B and 90.9 +/- 3.4% in group C (A bu not B significantly higher than C). Midradial BMD measured by DPX was 99.3 +/- 1.3% in A, 94.8 +/- 4.0% in B and 85.5 +/- 6.2% in C. The ratio of whole body calcium content between the 12th and 18th month was 96.5 +/- 1.7% in A, 90.1 +/- 2.7% in B and 89.8 +/- 1.3% in C (A but not B significantly smaller than C). Final/baseline ratio of urinary Ca/creatinine was 91.7 +/- 11.1 in A, 111.4 +/- 18.9 in B and 125.2 +/- 12.6 in C.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of calcium supplementation on bone density and parathyroid function in elderly subjects. 756 55

The outcome and metabolic control was studied in 60 critically ill patients with acute renal failure (ARF) treated by continuous arteriovenous hemodiafiltration (CAVHD) in a single surgical intensive care unit. Mean age (+/- SEM) was 60 +/- 2 years with a male predominance (80%). The majority of patients required mechanical ventilation (83%) and/or vasopressor support (70%) and suffered from multiorgan failure [mean number of organ system failures 3.3 +/- 0.3 (range 1-6)]. CAVHD resulted in a rapid decline of serum urea and creatinine levels during the first 72 h (urea 47.4 +/- 2.3 to 30.3 +/- 1.4 mmol/l, p < 0.05, and creatinine 572 +/- 27 to 361 +/- 23 mumol/l, p < 0.05); thereafter, controlled steady-state levels were achieved with serum urea levels kept below 30 mmol/l with full protein alimentation and often despite hypotension, surgery and septicemia. Significant electrolyte derangements could be easily corrected and maintained within normal limits. Bicarbonate homeostasis could be restored within 48 h in patients with severe metabolic acidosis (HCO3- < 20 mmol/l) with use of bicarbonate as a buffering anion (17 +/- 0.5 to 23.2 +/- 0.6, p < 0.05). CAVHD allowed rapid removal of excess body and lung water (up to 5 liters/day) without hemodynamic instability. Despite a mean pretreatment APACHE II score of 26.5, 26 patients (43%) survived until discharge from the intensive care unit, of whom 23 (38%) survived to leave hospital. Requirement of mechanical ventilation or vasopressor support, higher APACHE II scores and septicemia were all associated with a poor prognosis.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:High-risk surgical acute renal failure treated by continuous arteriovenous hemodiafiltration: metabolic control and outcome in sixty patients. 756 1

Acid extrusion is essential for osteoclast (OC) activity. We examined Na+ and HCO3(-)-independent H+ extrusion in rat- and mouse OCs by measuring intracellular pH (pHi) changes, with the pHi indicator BCECF (biscarboxyethyl-5-(6) carboxyfluorescein) after H+ loading with an ammonium pulse. 90% of OCs attached to glass do not possess HCO3- and Na(+)-independent H(+)-extrusion (rate of pHi recovery = 0.043 +/- 0.007 (SEM) pH U/min, n = 26). In contrast, in OCs attached to bone, the pHi recovery rate is 0.228 +/- 0.011 pHi U/min, n = 25. OCs on bone also possess a NH(4+)-permeable pathway not seen on glass. The bone-induced H+ extrusion was inhibited by salmon calcitonin (10(-8) M, for 2 h), and was not present after pretreating the bone slices with the aminobisphosphonate alendronate (ALN). At ALN levels of 0.22 nmol/mm2 bone, H+ extrusion was virtually absent 12 h after cell seeding (0.004 +/- 0.002 pH U/min) and approximately 50% inhibition was observed at 0.022 pmol ALN/mm2 bone. The Na(+)-independent H+ extrusion was not inhibited by bafilomycin A1 (up to 10(-7) M), although a bafilomycin A1 (10(-8) M)-sensitive H+ pump was present in membrane vesicles isolated from these osteoclasts. These findings indicate that Na(+)-independent acid extrusion is stimulated by osteoclast attachment to bone and is virtually absent when bone is preincubated with ALN, or when osteoclasts are treated with salmon calcitonin.
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PMID:Acid extrusion is induced by osteoclast attachment to bone. Inhibition by alendronate and calcitonin. 759 14

Following the acute diarrhea in patients (n = 24) overnight with commonly used laxatives for bowel preparation, the changes in electrolytes and acid-base balance in blood and urine were investigated. Though no alterations of serum sodium or potassium concentrations were noted, mild but significant reduction of mean values (+/- SEM) of plasma pH and HCO3 after diarrhea when compared to those before it developed (pH, from 7.42 +/- 0.01 to 7.39 +/- 0.01, p < 0.01; HCO3, from 25.8 +/- 0.6 to 23.7 +/- 0.6 mEq/L, p < 0.05). However, significant reduction of concentration in spot urine sodium from 150 +/- 12.3 to 93 +/- 14 mEq/g of crea. (p < 0.01) and increase in spot urine potassium from 33 +/- 3.2 to 51 +/- 6.0 mEq/g of crea. (p < 0.05) following diarrhea were seen with significant reduction of urine pH from 6.67 +/- 0.21 to 5.5 +/- 0.13 (p < 0.001). Also, with this effective urinary acidification following diarrhea, a significant reduction of urinary anion gap as well as significant increment of spot urine ammonium was accompanied (anion gap, from 80.4 +/- 11.1 to 44 +/- 8.5 mEq/g of crea. p < 0.001; ammonium, from 87 +/- 18.5 to 229 +/- 37 mg/g of crea. p < 0.001) in addition to the significant inverse correlation between these changes in spot urine from basal levels in 24 study subjects (y = -1.13 x +61, r = 0.7, p < 0.001). In conclusion, we observed that the acute diarrhea with laxatives used for bowel preparation caused a mild degree of metabolic acidosis with no changes in blood electrolytes.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The changes in electrolytes and acid-base balance after artificially induced acute diarrhea by laxatives. 770 87


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