Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Magnesium Compounds”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 883 records · Page 49Linked to original sources
PubMed2002

Evaluation of trends in frequency of urethrostomy for treatment of urethral obstruction in cats.

OBJECTIVE: To determine hospital proportional morbidity rates (HPMR) for urethral obstructions, urethral plugs or urethroliths, and urethrostomies in cats in veterinary teaching hospitals (VTH) in Canada and the United States between 1980 and 1999. DESIGN: Epidemiologic study. ANIMALS: 305,672 cats evaluated at VTH. PROCEDURES: Yearly HPMR were determined for cats with urethral obstructions, urethral plugs or urethroliths, or urethrostomies from data compiled by the Purdue Veterinary Medical Database. The test for a linear trend in proportions was used. RESULTS: Urethral obstructions were reported in 4,683 cats. Yearly HPMR for urethral obstructions declined from 19 cases/1,000 feline evaluations in 1980 to 7 cases/1,000 feline evaluations in 1999. Urethral plugs or urethroliths affected 1,460 cats. Yearly HPMR for urethral plugs or urethroliths decreased from 10 cases/1,000 feline evaluations in 1980 to 2 cases/1,000 feline evaluations in 1999. A total of 2,359 urethrostomies were performed. Yearly HPMR for urethrostomies decreased from 13 cases/1,000 feline evaluations in 1980 to 4 cases/1,000 feline evaluations in 1999. CONCLUSIONS AND CLINICAL RELEVANCE: Frequency of feline urethrostomies performed at VTH in Canada and the United States declined during the past 20 years and paralleled a similar decline in frequency of urethral obstructions and urethral plugs or urethroliths. These trends coincide with widespread use of diets to minimize struvite crystalluria in cats, which is important because struvite has consistently been the predominant mineral in feline urethral plugs during this period.

Animal Feed↗
PubMed2005

Early biochemical alterations in manganese toxicity: ameliorating effects of magnesium nitrate and vitamins.

Manganese-induced early biochemical changes and effects of supplementation of magnesium nitrate (Mg(NO3)2) and antioxidant vitamins (A, C, D and E) were studied in rats intoxicated with manganese. Significant elevation in the level of chlorides in plasma, erythrocytes, liver and cerebellum, and a decrease in plasma inorganic phosphate (pi) with an increase in liver pi were observed in animals exposed to manganese as compared to controls. The level of erythrocyte-acid labile phosphate (ALP), nicotinamide adeninedinucleotide (NAD+) and plasma sialic acid (N-acetylneuraminic acid, NANA) also increased significantly. Elevated levels of chlorides in plasma, erythrocytes and cerebellum reversed to normal control values whereas liver chlorides restored partially by the supplementation of Mg(NO3)2. Vitamins supplementation was effective to reverse chlorides level in erythrocytes, liver and cerebellum. Decreased level of pi in plasma and the highly elevated level of erythrocyte ALP were also recovered in animals received Mg(NO3)2 in addition to MnSO4. However, such effect of Mg(NO3)2 was not seen in lowering the elevated level of NANA that restored by the administration of vitamins. Thus, the early alterations in plasma levels of chlorides, pi, and NANA and erythrocyte-ALP seem to be an indicative of early manganese toxicity while Mg(NO3)2 and vitamins supplementation appear to provide, at least in part, protection against manganese toxicity.

Animals↗
PubMed1983

Crystalline composition of urinary stones in Norwegian patients.

During a 5 year period, 500 stones from the upper urinary tract and 100 from the urinary bladder of as many unselected and consecutive patients were obtained in one hospital and analysed crystallographically. 90.4% of the upper urinary tract stones and 65% of the bladder stones belonged to the groups of calcium stones, while 6.6% and 24%, respectively, were triple phosphate stones. The contribution of calcium stones to this material is higher and that of triple phosphate stones lower than in comparable materials. Frequency variations between materials also exist within the groups of calcium stones, and for uric acid, urate and cystine stones. On the basis of published material, it is not possible to say if these differences are renal or reflect variations in the selection of stones and the methods of analysis. Reports on stone materials should include information on these aspects in order to allow meaningful comparison. Distinction between stones from the upper urinary tract and from the bladder is mandatory. The composition pattern reported here is believed to be as representative as is possible to obtain. A major part of stones from the upper urinary tract is, however, lost for analysis following spontaneous passage. Such stones are more often pure calcium oxalate and less often triple phosphate stones than those which are obtained by surgical methods, and the extent to which they are obtained will influence the findings in stone materials.

Adult↗
PubMed1983

Correlation between causes and composition of urinary stones.

On the basis of routine clinical and laboratory investigations, one or more probable or possible causes of stone formation were established in 27% of upper urinary tract and 98% of bladder stone patients. In the upper urinary tract, causes were usually found for triple phosphate and pure calcium phosphate stones and rarely for pure calcium oxalate stones. Except for cystine stones and largely for triple phosphate stones there was no definite correlation between the composition of stone and causes. Uric acid and urate stones were often not associated with obvious causes, but their demonstration should lead to further investigations. In a small group of recurrent calcium stone formers examined for hypercalciuria, hyperoxaluria, hyperuricosuria, and renal tubular acidosis, positive findings were noted for 65%, but there was no consistent correlation between these findings and the types of stone. Stone analysis is most useful in so far as it identifies or excludes triple phosphate, cystine, and uric acid/urate stones. This may be done by simple chemical analysis. Certain rare components may, however, be overlooked, as will details of stone structure, unless crystallographic methods are employed.

Bacterial Infections↗
PubMed1983

Quantitative observations on the crystalline composition of urinary stones.

Quantitative analytical findings on upper urinary tract stones from 500 patients are reported and compared to data in the literature. Methods of presentation of quantitative data are discussed. A wide range of findings between recurrent stones in the same patient and between stones from patients with the same cause of stone formation was found. No immediate clinical value of quantitation can be seen, but larger materials and correlation with metabolic investigations in stone formers may reveal correlations of clinical interest. Quantitative observations may identify groups of patients and types of stones not recognised on the basis of qualitative analysis. Examples of this are given for calcium oxalate-calcium phosphate stones and for stones containing brushite. The organic matrix which usually contributes 2-3% of stone mass was not considered, but distinctly visible and separate organic material in 7 stones was quantitated by visual estimate. 32 stones were incomplete, and their quantitation may not be wholly representative. Their exclusion, however, would have led to major bias because most were large and nearly half were triple phosphate stones, both properties being relatively rare. In cases of multiple stones, usually only one was quantitated. Seventy patients provided more than one stone for analysis (Otnes, 1983b), but except when specifically stated only the first stone is considered.

Calcium Oxalate↗
PubMed1989

The relation between urinary tract infections and stone composition in renal stone formers.

During a seven-year period (1975-1981) a total of 1325 patients hospitalized for stone disease were studied as to the occurrence of positive urine cultures. Urinary stones from 535 surgically treated patients were analyzed with infrared spectrophotometry and the relationships between stone composition, level of surgery and bacteriological strains were studied. Positive urinary cultures were found in 34% of the surgically treated patients and in 21% of those not operated upon. Among the surgically treated patients with urinary tract infection (UTI) E. coli was the most frequent microorganism (35%), followed by Proteus (28%). Patients with Proteus infection had the highest frequency of UTI episodes, most of which occurred before hospitalization. There was a higher frequency of magnesium ammonium phosphate (MAP) calculi among patients with Proteus infection than among those with non-Proteus infection, in whom no difference in stone composition was found. Patients infected with E. coli had more phosphate-containing stones (CaP+MAP) than non-infected patients. The highest frequency of oxalate calculi (CaOx+CaOx/CaP) was found among patients without infection. No E. coli infections were seen in male patients with CaP and MAP calculi. MAP stones were most often found in the kidney and oxalate stones in the ureter.

Calcium Oxalate↗
PubMed1993

Acidification of urine is not a feasible method for preventing encrustation of indwelling urinary catheters.

Encrusting deposits form on urinary catheters as a result of infection by bacteria which produce urease. Urease catalyses the hydrolysis of urea to produce ammonia, with the result that the pH of the urine increases and the deposits are precipitated. It has been suggested that acidification of urine may prevent this rise in pH and so prevent encrustation. Experiments were performed in vitro to determine whether acidification could be used to prevent the rise in pH when urease is present in urine. It was found that, in the presence of urease, the initial decrease in pH resulting from acidification was countered by further urea being converted into ammonia. Thus, although acidic washout solutions may dissolve encrusting deposits, acidification of urine is not a feasible method for preventing catheter encrustation.

Acid-Base Equilibrium↗
PubMed1993

Stone recurrences in kidneys made stone-free by percutaneous extraction.

Of 100 renal units which were made stone-free by percutaneous stone extraction in 1985, 86 (86.0%) were re-examined radiologically up to 5 years after operation. The re-examination was performed because of symptoms or as part of a regular check-up or after calling the patient. Intrarenal calcifications were diagnosed in 27 of 86 (31.4%) of the renal units, but only in 11 (12.8%) were there stones requiring treatment.

Adolescent↗
PubMed1995

Study on calcium oxalate monohydrate renal uroliths. III. Composition and density.

Density and content of mineral constituents were determined for 33 human calcium oxalate monohydrate (hereafter COM) uroliths whose external appearance and inner structure were described in part I and II respectively. Studied stones contained 0.13-0.42 wt.% of struvite, 0.68-4.12 wt.% of hydroxyapatite, 73-96 wt.% of COM and 3-10 wt.% of water unbound in a crystallohydrate 10 to 20 wt.% of calculus mass is not accounted for by chemical analysis. Density of COM calculi varying between 1.67 and 2.06 g cm-3 is not a function of any single stone parameter. Around 30% of stone volume is not occupied by crystalline components. The mulberry stones of sedimentary origin contained higher amount of organic matter than papillar and mulberry stones displaying site of attachment to epithelium.

Calcium Oxalate↗
PubMed1990

Modulation of lung-associated natural killer activity by resident and activated alveolar macrophages.

Alveolar macrophages (AM) freshly obtained by bronchoalveolar lavage suppressed significantly, in a dose-dependent fashion, lung interstitial lymphocytes cytotoxicity against the NK-sensitive target cells, YAC-1. Kinetic experiments revealed that AM-mediated suppression of NK activity was seen following short-term incubation of AM with lymphocytes (4 h) and was unchanged after a 24 h co-culture period. Freshly obtained lung lymphocytes and lymphocytes incubated for 24 h were similarly inhibited by AM. In addition, incubation of AM for 24 h did not abrogate their suppressive effect on lung NK activity. Interestingly, AM-conditioned media, also caused a significant inhibition of lung NK activity. Furthermore, in vitro activation of AM with lipopolysaccharide (LPS, 5 micrograms/ml) and muramyl dipeptide (MDP, 20 micrograms/ml) significantly enhanced the inhibitory effect of AM on lung NK activity. Similarly, in vivo activation of AM locally by intratracheal instillation of attapulgite, an inflammatory agent, resulted in greater AM-mediated down regulation. Taken together, these data indicate that lung NK activity is modulated by locally derived factors and suggest that pharmacologic manipulation of AM may play a determining role in the activation of lung NK activity by biological response modifiers (BRM).

Animals↗
PubMed1988

Lactational responses to dietary magnesium, potassium, and sodium during winter in Florida.

Forty-eight midlactation Holstein cows were used to evaluate dietary treatments arranged as a 4 x 2 x 2 factorial: .26, .38, .48, or .60% Mg, .24 or .62% Na, and 1.14 or 1.59% K. Supplemental Mg, K, and Na were supplied by feed-grade magnesium phosphate, potassium bicarbonate, or sodium chloride. All dietary treatments were equal in Ca and P. There were no effects of dietary Na or K on feed intake or milk production. Feed intakes were equal with .26, .38, and .48% Mg but declined 4.9% with .60% Mg. Milk yields responded curvilinearly to dietary Mg. Similarly, 4% FCM yields responded curvilinearly, increasing 7% with .48% Mg compared with .26% Mg then declining with .60% Mg. Milk fat percentages were unaffected by dietary Mg concentration, but milk fat yields responded curvilinearly. Milk protein percentages declined linearly as dietary Mg increased. Plasma Mg concentrations increased linearly from 2.52 to 2.68 mg/dl as dietary Mg increased. Renal fractional excretions of Ca responded curvilinearly as dietary Mg increased and decreased as dietary K increased. Results of this experiment suggested that current recommendations for dietary Mg do not maximize lactational performance. A companion laboratory experiment showed that feed-grade magnesium phosphate had less alkalizing capacity than two MgO sources.

Animals↗
PubMed2002

Preventing kidney stones: calcium restriction not warranted.

The traditional wisdom on preventing calcium stones, the most common form of kidney stone, has been to advise patients to limit dietary calcium. Research has proved this wrong, however. Normal dietary calcium intake, along with reduced salt and protein, is now advised. This paper also summarizes the diagnosis and treatment of the less-common forms of kidney stones-struvite, uric acid, and cystine.

Calcium, Dietary↗
PubMed1985

Investigation and treatment of renal calculi.

We have investigated and treated 176 patients who were suffering from renal calculi. The stones contained calcium in 87% of patients, predominantly urate in 11%, and rarely contained magnesium ammonium phosphate or cystine. Of the patients with calcium stones, hypercalciuria was present in 75% and was identified in 57% by the measurement of the 24-hour urinary calcium excretion, and in a further 18% by a standardization calcium "fast-and-load" test. Nine patients were found to have primary hyperparathyroidism and were treated surgically. A further 21% were suspected to have normocalcaemic hyperparathyroidism, and metabolic studies are being developed to clarify this. The treatment of hypercalciuria included a low-calcium diet, and various combinations of a thiazide diuretic, phosphate supplements and sodium cellulose phosphate. Hypercalciuria was controlled in all compliant patients, and only two developed further stones. Hyperuricosuria was rarely the sole metabolic abnormality in patients with calcium stones, though this might reflect the referral pattern of the Unit. Uric acid stones were frequently, but not invariably, associated with hyperuricosuria and acid urine, and even large uric acid calculi dissolved with a combined therapy of high fluid intake, allopurinol and an alkalinizing agent. Surgical treatment was rarely required in these patients. A stone in the renal pelvis of one patient was removed percutaneously and did not require ultrasonic fragmentation. Modern methods of investigation and treatment have greatly improved the outlook for patients with recurrent renal calculi.

Calcium↗
PubMed1984

Repression of beta-lactam production in Cephalosporium acremonium by nitrogen sources.

A variety of inorganic and organic nitrogen sources were added to fermentation media to determine their regulatory effects on the production of beta-lactam antibiotics by Cephalosporium acremonium. (NH4)2SO4 at concentrations higher than 100 mM (1.3%) strongly inhibited beta-lactam production. L-Asparagine and L-arginine proved to be the best nitrogen sources tested for beta-lactam production. The optimum concentration of asparagine was 1.2%. Higher concentrations led to NH3 accumulation, increase in pH, and lower growth rates. Addition of tribasic magnesium phosphate [Mg3(PO4)2 X 8H2O] to the (NH4)2SO4-containing medium stimulated beta-lactam production markedly and ammonium repression of the ring-expansion enzyme was reversed. It appears that the ring-expansion step is a very sensitive part of beta-lactam biosynthesis in C. acremonium with respect to nitrogen source repression. Other enzymes may also be sensitive in view of the fact that nitrogen source derepression not only led to increases in cephalosporin C but, to a lesser extent, penicillin N and total beta-lactam titers.

Acremonium↗
PubMed1986

Nitrogen repression of gilvocarcin V production in Streptomyces arenae 2064.

Analysis of gilvocarcin V production by Streptomyces arenae in complex and chemically defined media revealed strong nitrogen repression of antibiotic biosynthesis. Nitrogen regulation was first suggested by the observation of a 10-fold increase in gilvocarcin V production when the ammonium ion trapping agent Mg3(PO4)2.8H2O was added to complex medium. In a chemically defined medium, cell mass increased as the initial ammonium sulfate concentrations approached 7.5 mM; however, antibiotic production was strongly repressed at ammonium sulfate concentrations exceeding 1.5 mM. Repression of gilvocarcin V production at 7.5 mM ammonium sulfate was maximally reversed by adding Mg3(PO4)2.8H2O to the medium at 25 mM; specific antibiotic production attained a level 2.5-fold higher than at the nonrepressive ammonium salt concentration of 1.5 mM. Evaluation of the effects of soluble inorganic phosphate concentrations upon gilvocarcin V titers suggested that the relatively insoluble Mg3(PO4)2.8H2O must in fact serve as an ammonium ion-trapping agent, as previously reported in other fermentation systems, not as a supplementary source of phosphate for growth and antibiotic production. These studies also revealed a minor repression of antibiotic synthesis at elevated levels of soluble phosphate. Comparisons of several amino acids as nitrogen sources in a Mg3(PO4)2.8H2O-containing medium indicated that L-aspartic acid and glycine promoted the highest yields of gilvocarcin V. Metabolism of these two amino acids into precursors of the polyketide pathway for gilvocarcin V biosynthesis is postulated.

Amino Acids↗