Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Magnesium-diltiazem cardioplegia was evaluated in the intact, perfused rat heart to determine whether the joint administration of these agents would adversely affect myocardial contractile and high-energy phosphate recovery following intermittent, normothermic global ischemic arrest. Sequential metabolic and functional analyses were performed on isolated perfused rat hearts during each phase of the experimental protocol: control (10 min), normoxic cardioplegia (10 min), intermittent global ischemic arrest (two 15-min periods separated by 2 min infusion of the normoxic cardioplegic perfusate), and normoxic postischemic control reperfusion (60 min). Four different cardioplegic solutions were evaluated: 30 mM KCl, 30 mM KCl with 2 mg diltiazem/liter, 20 mM MgCl2, and 20 mM MgCl2 with 2 mg diltiazem/liter. Myocardial phosphatic metabolite levels and intracellular pH were analyzed nondestructively in the intact hearts by phosphorus-31 NMR spectroscopy. Corresponding measurements of peak left intraventricular pressure, rate of peak pressure development (dP/dt), and contraction frequency were performed at the midpoint during each 5-min interval of 31P NMR signal averaging. Magnesium plus diltiazem-treated hearts were distinguished from all other groups by a marked delay in postischemic functional recovery consisting of a prolonged depression in contractility (34% of control, P less than 0.01) that persisted throughout the first 50 min of postischemic reperfusion. Diltiazem in combination with magnesium cardioplegia was detrimental to postischemic functional recovery, despite a rapid restoration of high-energy phosphate stores. The apparent adverse interactive effects of excess magnesium and diltiazem suggest that elective ischemic arrest with magnesium cardioplegia in combination with diltiazem may be contraindicated clinically. The mechanistic basis and drug specificity of this response require further clarification. The present findings appear to exclude ATP and PCr production, and structural causes as the basis for the observed aberrant functional recovery from global ischemia of magnesium plus diltiazem-arrested hearts.
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PMID:Sustained postischemic cardiodepression following magnesium-diltiazem cardioplegia. 371 20

Previous work has demonstrated that myocardial ischemia results in a breakdown of the excitation-contraction coupling system of cardiac muscle associated with lysosomal activation. It has been hypothesized that lysosomal activation during the course of myocardial ischemia is mediated by the production of oxygen free radicals. We have tested the hypothesis that myocardial ischemia results in the activation of lysosomal phospholipase C and disruption of calcium transport in sarcoplasmic reticulum (SR) mediated by oxygen free radicals. Three groups of dogs were studied: sham-operated controls (n = 6); normothermic global ischemia of 30-min duration (n = 6); and 30 min of normothermic global ischemia pretreated with intracoronary superoxide dismutase (SOD, 10 micrograms/ml) plus catalase (25 micrograms/ml). In vitro, isolated SR demonstrated a significant depression of calcium uptake rates and Ca2+-stimulated, Mg2+-dependent ATPase activity at both pH 7.0 and 6.4 with the depression at pH 6.4 greater than 7.0. This depression of SR function was significantly inhibited in hearts pretreated with SOD plus catalase. In sham-operated controls, acid-induced dysfunction was associated with substantial loss of phospholipid phosphorus and major changes in phospholipid composition. SR contained an extremely active, ion-independent sphingomyelinase-phospholipase C (SM-PLC) that had maximal activity at pH 4.5-5.0. This SM-PLC was activated when control SR was incubated at acid pH and the specific activity of SM-PLC was decreased 50% in SR isolated from normothermic global ischemia. Activity remained at control levels in hearts pretreated with SOD plus catalase.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Sarcoplasmic reticulum dysfunction: phospholipid alterations induced by lysosomal phospholipase C. 377 91

The effect of high levels of dietary magnesium (1.4%) alone or in combination with elevated calcium (1.8%) or phosphorus (1.6%) on growth and health of male calves was evaluated during a nine week feeding trial after weaning. Twenty calves were randomly divided into 4 feeding groups consisting of controls, high magnesium, high magnesium and calcium or high magnesium and phosphorus. Elevated dietary minerals caused decreased feed intake and growth rate. Blood urea nitrogen and serum creatinine levels were greatly elevated in calves fed high magnesium or magnesium and phosphorus and serum urea nitrogen was moderately elevated in calves fed high magnesium and calcium. These elevations suggested the occurrence of renal damage as a result of microcrystalline obstruction of renal tubules. Serum magnesium levels were three times normal in calves fed high magnesium or magnesium and phosphorus, but only twice normal in calves fed high magnesium and calcium. High dietary magnesium resulted in a significant depression in blood calcium level. This effect was somewhat overcome by additional dietary calcium Three calves fed the high magnesium diet and two calves fed the high magnesium and phosphorus diet developed urinary tract obstruction. The chemical composition of uroliths recovered from these calves was calcium apatite. Elevated dietary magnesium has been shown to be a cause of urolithiasis in growing male calves. Additional dietary calcium, but not phosphorus, appears to protect calves against urolithiasis induced by elevated dietary magnesium.
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PMID:Dietary magnesium and urolithiasis in growing calves. 380 29

The performance of 1680 male and female broiler chickens given diets with either a low (4.7-4.3 g/kg) or high (8.9-8.2 g/kg) content of inorganic phosphorus and four (150, 200, 250 and 300 mEq/kg) electrolyte balances (Na+K-Cl) was measured from 1-d-old to 49 d of age. Diets with the higher concentration of inorganic phosphorus reduced body weight gains in the starter (P less than 0.01) and finisher (P less than 0.05) phases but the efficiency of food utilisation was reduced only in the starter phase (P less than 0.05). The reduction in body weight gain was greater in males than in females. The growth depression caused by the higher concentration of inorganic phosphorus in the finisher diets was partially alleviated by increasing the electrolyte balance to either 250 or 300 mEq/kg diet. The higher concentration of inorganic phosphorus significantly reduced the dressing percentage and increased the abdominal fat pad weight and litter moisture content. Electrolyte balance had no significant effects on efficiency of food utilisation, abdominal fat pad weights or litter moisture content. Neither the dietary concentration of phosphorus nor the electrolyte balance had a significant effect on mortality or ash content of the tibia.
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PMID:Effect of dietary phosphorus concentration and electrolyte balance on the growth performance of broiler chickens. 381 28

After surgical placement of end-to-side portacaval shunts (PCS), 4 adult mongrel dogs (11.8 to 18.2 kg) were fed purified diets and monitored for approximately 50 weeks for changes in body weight, neurologic status, and an array of clinically important biochemical variables. Two healthy dogs, fed the same diets and maintained in the same environment, were also observed (controls). Body weights were relatively stable over the period of observation. The branched-chain ratio ([valine] + [leucine] + [isoleucine]/[phenylalanine] + [tyrosine]), an index of the degree of change in plasma amino acid concentrations, was significantly lower in dogs with PCS than in controls. Despite this depression in branched-chain ratio, the principals (dogs with PCS) were essentially free of neurologic symptoms. Statistically significant decreases due to portacaval shunting were seen in the serum concentrations of glucose, calcium, urea nitrogen, creatinine, cholesterol, and albumin. Total protein, globulin, and triglyceride concentrations tended to be lower in the serum of principals than in serum of controls, but the differences were not statistically significant. Statistically significant increases due to portacaval shunting were seen in plasma concentrations of total conjugated bile acids and sulfobromophthalein retention. Concentrations of the following compounds tended to be higher in serum of principals than in serum of controls: phosphorus, chloride, uric acid, total bilirubin, lactate dehydrogenase, aspartate transaminase, alanine transaminase, and alkaline phosphatase. Liver biopsy at 7 months after operation showed mild-to-extensive atrophy of hepatocytes, mild-to-extensive fibrosis, and collapsed portal veins in all principals examined.
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PMID:Long-term biochemical and physiologic effects of surgically placed portacaval shunts in dogs. 395 18

The administration of radioactive phosphorus and testosterone benefitted two-thirds of thirty patients with prostate cancer treated. Subjective relief of bone pain occurred in 73% of cases and measurable objective improvement occurred in 50%. Hematopoietic depression occurred in 30% of the patients necessitating readmission to hospital for transfusion. This method of treatment is advocated for patients with widespread osseous metastasis, especially those with severe pain.
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PMID:Carcinoma of the prostate: the treatment of bone metastases by radioactive phosphorus (32P). 401 87

Prolonged global ischemia results in a defect in oxygen extraction during early reperfusion. This study was thus undertaken to assess the effects of maintaining cardioplegia at the onset of reoxygenation in view of channeling available energy toward reparative cell processes rather than mechanical activity. Twenty-four isolated perfused rat hearts were subjected to 120 min of 15 degrees C ischemia. Group I (control) was reperfused with the standard Krebs perfusion medium whereas in groups II and III the initial reperfusate consisted of an oxygenated alkaline cardioplegic solution prior to the resumption of Krebs perfusion. Oxygenation of the cardioplegic reperfusate was ensured by fluorocarbons at a concentration of 10% (O2 content: 5.5 vol %; group II) or 20% (O2 content: 9 vol %; group III). In addition to hemodynamical determinations, high-energy phosphates and intracellular pH were monitored serially by phosphorus-31 nuclear magnetic resonance spectroscopy. After 30 min of reperfusion postischemic recovery of aortic flow was better in group II (74.0 +/- 5.9% of control) than in group I (59.1 +/- 5.4% of control, P less than 0.05). This functional improvement correlated with a higher postischemic increase in phosphocreatine levels (103.21 +/- 11.21% vs 74.12 +/- 3.59%, at 3 min of reperfusion, P less than 0.05) without significant differences in total ATP content. Group III hearts exhibited a slow recovery as evidenced by a severe depression in aortic flow, coronary arteriovenous difference, and total phosphate content during the 15 initial minutes of reperfusion. These results show that the protection provided by cardioplegia can be improved by a fluorocarbon-oxygenated cardioplegic reperfusate.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Enhanced cardioplegic protection by a fluorocarbon-oxygenated reperfusate: a phosphorus-31 nuclear magnetic resonance study. 403 5

The effects of the mineral elements, calcium and available phosphorus (aP), and the electrolytes, sodium, potassium and chloride in the diet on the growth and physiology of male broiler-type chickens were investigated. The concepts of total dietary cation-anion and electrolyte (Na + K - Cl, meq/kg) balance were compared for their ability to describe observed growth and various parameters to 42 d of age. There were 12 dietary treatments; each was given to four replicates of 32 birds housed in a deep-litter, environmentally controlled shed. Diets were nutritionally adequate and were based on practical ingredients. Total cation-anion balance was varied from 327 to 700 meq/kg and electrolyte balance, from -29 to 553 meq/kg. Results showed that total dietary cation-anion balance did not describe the growth of chickens as well as electrolyte balance. Low (less than 180 meq/kg) or high (greater than 300 meq/kg) electrolyte balance in a diet led to depressed liveweight at 42 d of age. There was an optimum electrolyte balance from 250 to 300 meq/kg. The extent of liveweight depression from feeding diets with an electrolyte balance greater than 300 meq/kg depended on the type of cation added to the diet (Na or K): the range of the Na:K ratio for optimum growth was 0.5-1.8. Acid-base balance was influenced mainly by a diet with a low electrolyte balance (-29 meq/kg). Plasma ion levels (Ca, inorganic P, Mg, Na, K, Cl) were unaffected by dietary treatment, except that high dietary calcium reduced plasma inorganic P levels. Increasing calcium from 1.30 to 1.74% reduced liveweight at 42 d of age by 5%, but subsequent increases up to 2.30% Ca had relatively minor effects. Liveweight tended to be lower for birds fed a diet containing 1.30% Ca and 0.81% aP compared to 0.45% aP with 1.30% Ca. Total cation-anion balance cannot be used in preference to dietary electrolyte balance to describe growth of broiler chickens. However, even though there was a good relationship between growth and dietary electrolyte balance, there were specific cation effects (Na and K) independent of electrolyte balance.
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PMID:The effects of dietary minerals and electrolytes on the growth and physiology of the young chick. 406 59

Two metabolism trials were conducted with 12 crossbred wether lambs, each surgically equipped with a ruminal catheter and abomasal and ileal cannulae, to study the effect of K infusion in different sites of the digestive tract on site of absorption and flow of minerals. The treatments consisted of the infusion of 33.6, 12.0 or 12.0 g K/d as bicarbonate into either the rumen, abomasum or ileum, respectively. Each trial consisted of a minimum 5-d preliminary period, five 3-d collection periods to determine mineral balance and a 6-d sampling period to determine mineral flow and site of absorption. Chromic oxide was incorporated into the diet for use as a marker. Magnesium was absorbed primarily from the preintestinal region. Ruminal infusion of K tended to decrease preintestinal Mg absorption. Absorption of Mg in the entire tract was decreased (P less than .05) 43% when K was infused into the rumen. There was a slight absorption of Mg in the small intestine, followed by a net secretion into the large intestine. Serum Mg levels tended to be depressed in lambs infused with K intraruminally. Calcium flow from the preintestinal region was decreased (P less than .05) by infusion of K into the rumen. Only lambs infused with K in the rumen had a net secretion of Na into the small intestine. The large intestine was the primary site of net Na absorption for ruminal-infused lambs. Phosphorus flow from the preintestinal region was decreased (P less than .05) by infusion of K into the rumen. Potassium flow from both the preintestine and small intestine was increased (P less than .05) by ruminal K infusion. The infusion of K into the rumen, abomasum or ileum increased (P less than .05) the total absorption of K, with the small intestine being the major absorptive site. The infusion of potassium bicarbonate into the rumen of sheep raised (P less than .05) the pH of the ruminal contents 15%. Ruminal infusion of K depresses Mg absorption, while the infusion of K into the abomasum or ileum does not affect Mg absorption. Therefore, the role of K in grass tetany may be via this depression of Mg absorption.
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PMID:Absorption of magnesium and other macrominerals in sheep infused with potassium in different parts of the digestive tract. 407 68

In previous work we found that vitamin D-deficient and also calcium-deficient rats developed hypocalcemia and an impairment of bone formation and mineralization. The present study of thyroparathyroidectomized (TPTX) rats was undertaken to determine the effect of hypocalcemia without secondary hyperparathyroidism. TPTX rats fed a normal diet developed hypocalcemia and hyperphosphatemia in association with impairment of osteoblastic bone matrix formation and of mineralization of newly formed matrix. The serum calcium x phosphorus product was not decreased. The decreased formation was largely due to a reduction in matrix apposition indicating decreased synthetic activity of individual ostcoblasts. In contrast to the above results, when TPTX rats were fed a high-calcium diet to prevent hypocalcemia, no impairment of either formation or mineralization was found. From the results of these two experiments, it is reasonably certain that hypocalcemia was responsible for the inhibition of formation and mineralization. Moreover, based on the magnitude of the changes in serum calcium and bone parameters in TPTX rats, hypocalcemia could have accounted for the inhibition of formation and mineralization in calcium-deficient as well as vitamin D-deficient rats. In TPTX rats the mineralization defect was manifested by decreases in both the rate of osteoid maturation (indicating a delayed onset of mineralization) and the rate of mineralization. A strong correlation (r = 0.95, P < 0.001) was observed between these two rates suggesting a tight coupling of these two aspects of mineralization.TPTX rats also had lower bone resorption rates and higher serum phosphorus levels than sham-operated animals when the normal calcium diet was fed but not when the high-calcium diet was fed. Thus the inhibition of bone resorption in TPTX rats was at least partially prevented by correction of hyperphosphatemia. This is consistent with previous work showing an inverse relationship between serum phosphorus and bone resorption. Accordingly, the depression of bone resorption in TPTX rats was probably due to hyperphosphatemia as well as to hypoparathyroidism.
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PMID:Inhibition of bone matrix formation, mineralization, and resorption in thyroparathyroidectomized rats. 470 Apr 83


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