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 487 records · Page 27Linked to original sources
PubMed1991

Extracorporeal shock wave lithotripsy for struvite renal calculi: prospective study with extended followup.

To clarify the significance of retained stone particles after extracorporeal shock wave lithotripsy (ESWL) for struvite renal calculi we followed 22 otherwise healthy women for 16 to 52 months (mean 39 months). Each patient had persistent Proteus mirabilis bacteriuria before ESWL and received a standardized regimen of antimicrobial therapy in the perioperative period only. Of the 22 patients 19 (86%) were cured of the persistent bacteriuria. Of these 19 patients 16 had retained stone particles at the beginning of surveillance and 10 had retained particles at last followup. None of the particles produced symptoms or enlarged. However, 1 of the patients who was rendered stone-free had a P. mirabilis reinfection at 20 months and a new stone developed. Of the 22 patients 3 (14%) had continued persistent P. mirabilis bacteriuria after ESWL. Two patients were subsequently cured of the infection with antibiotics alone (1), and with antibiotics and extraction of a new ureteral stone (1). The remaining patient had expansion of retained stone particles after 51 months of surveillance. We conclude that a stone-free kidney is an unrealistic objective of ESWL monotherapy for struvite renal calculi. However, the treatment usually will eradicate the accompanying persistent bacteriuria and sterile stone particles will not enlarge during the first 2 to 4 years after treatment.

Adult↗
PubMed1991

Proteus mirabilis biofilm protection against struvite crystal dissolution and its implications in struvite urolithiasis.

Proteus mirabilis biofilm formation, struvite (MgNH4PO4.6H2O) crystal formation and dissolution in an artificial urine mixture were monitored using computer-enhanced microscopy (CEM) and a 1 x 3 mm. glass flow cell. Image analysis showed that P. mirabilis biofilm formation did not occur to any extent at macroenvironment flow rates greater than two mL/h (equivalent to a microenvironment flow rate of less than 5 microns./sec). Essentially, cells attached to glass surfaces, grew slowly and divided. Daughter cells were generally released directly into the medium where they could then presumably colonize other regions. Microcolonies formed by the adhesion of aggregates of cells from the medium, and over time grew into biofilms. Struvite crystallization due to urease activity and pH elevation above neutrality, was preceded by the deposition of organic matter on the glass surface, followed by the appearance of a number of tiny (one to two microns.) crystals. Crystals forming within a biofilm at low dilution rates took on a characteristic twinned or "X-shaped" appearance (crystal habit) indicative of a rapid growth rate. Those forming outside the biofilm took on a more tabular appearance reflecting their slower growth. When the macroenvironment flow rate of artificial urine (initial pH 5.8) in the glass flow cell was increased from two mL/h to four mL/h, struvite crystals not associated with biofilms dissolved within five to 10 min. Crystals entrapped within the P. mirabilis biofilm withstood flow rates up to 200 mL/h presumably due to the maintenance of an alkaline Mg-saturated microenvironment within the biofilm. These observations may suggest a mechanism by which struvite calculi can grow in spite of neutral or acidic urine pH and resist mild acidification therapy.

Bacterial Adhesion↗
PubMed1991

The fate of residual fragments after extracorporeal shock wave lithotripsy monotherapy of infection stones.

We reviewed 53 patients with infection stones treated by extracorporeal shock wave lithotripsy (ESWL*) monotherapy to determine the long-term rate free of stones and the stone recurrence rate as correlated with the pre-treatment stone burden and the radiological presence of sand or fragments after the procedure. Long-term followup (mean 26.6 months) was available on 33 patients representing 38 kidneys. Although only 3 kidneys were free of stones immediately after ESWL, 20 were without stones at 3 months and 18 (47%) were stone-free at followup. Of 9 kidneys with fragments of more than 5 mm. after the final treatment 7 (78%) had residual fragments at 3 months and experienced stone progression. Of 9 kidneys with sand remaining 6 (66%) and all 3 kidneys that appeared to be free of stones after ESWL were without stones at followup. The 3-month plain film of the kidneys, ureters and bladder was a reliable indicator of eventual outcome. Of 20 kidneys that were free of stones at 3 months 16 remained without stones. Of 18 kidneys with residual stone particles at 3 months 14 showed disease progression, 2 had stable disease and 2 passed residual sand. Only 1 of 17 patients who were free of stones or had stable stone disease had a positive urine culture at followup. Patients with infection stone fragments 3 months after ESWL monotherapy have a high rate of stone progression (78%) and should undergo further treatment. ESWL monotherapy of infection stones requires close patient followup to assure that all residual fragments have passed and urine remains sterile.

Adult↗
PubMed1991

High energy pulsed dye laser lithotripsy: management of ureteral calcium oxalate monohydrate calculi.

High energy pulsed dye laser lithotripsy (Candela MDL-2000), with energy output upgraded to a maximum of 140 mJ. at the laser fiber tip using the 320 mu core fiber, was compared to the initially commercialized device, with the energy output fixed at 60 mJ. using the 200 mu core fiber (Candela MDL-1). A total of 31 treatments in 28 patients was performed with the Candela MDL-1 device. Complete disintegration or at least fragmentation to spontaneously passable fragments occurred in 18 of 31 cases (58%). Only in 11 of the 24 calcium oxalate monohydrate calculi (46%) was fragmentation achieved. Another 73 laser lithotripsies in 72 patients were performed with the Candela MDL-2000 device. Complete disintegration or at least fragmentation to spontaneously passable fragments was achieved in 67 of 73 treatments (92%). Calcium oxalate monohydrate calculi were successfully treated in 41 of 45 procedures (91%). There was no response to the laser treatment in the only cystine calculus.

Adolescent↗
PubMed1989

Morphology of mineral deposits on encrusted urinary catheters investigated by scanning electron microscopy.

Struvite and hydroxyapatite were precipitated from artificial urine onto the surfaces of catheter materials by the controlled addition of urease. They were precipitated both together and separately (by omitting components of the artificial urine), and with and without the inclusion of albumin (which was intended to mimic the proteinaceous debris found in infected urine). Precipitates were identified by X-ray powder diffraction and the artificially encrusted surfaces examined by scanning electron microscopy. In the presence of protein, hydroxyapatite was precipitated as a poorly crystalline form which aggregated to form a crust. Struvite crystals could be easily identified under the scanning electron microscope by their relatively large size and characteristic appearance. Fifteen encrusted catheters from patients were also examined by scanning electron microscopy, and a further six using X-ray microanalysis. Their appearance was very similar to that of the materials encrusted in vitro. Encrustation involves the formation of hydroxyapatite and the growth of struvite crystals, intimately associated with bacteria.

Durapatite↗
PubMed1989

The kidney-ureter stone sexual paradox: a possible explanation.

The greater frequency of renal stones seen on excretory urograms in women, compared with the greater frequency of ureteral stones in men has been termed a sexual paradox. We assessed stone composition and weight, and sex as possible explanatory factors. A total of 4,014 renal and ureteral calculi was analyzed. For the 3,119 calculi in which only calcium oxalate and/or phosphate was detected by infrared and wet chemical analysis, there was a strong relationship between the oxalate-to-phosphate weight ratio and sex (p less than 0.0001). The mean weight for phosphate stones was 330 mg. but for oxalate stones it was 107 mg. Male-to-female ratios were 2.7, 2.2 and 1.8 for stone weight groups of 20 or less, 21 to 100 and more than 100 mg. The male-to-female ratio was 0.87 for the 171 stones containing magnesium ammonium phosphate; the average weight was 508 mg. for men and 1,560 mg. for women. The tendency for phosphate stones to be heavier and relatively more common in women compared to predominantly oxalate stones may partly account for the sexual paradox.

Calcium Oxalate↗
PubMed1988

Reduction of infection stones in rats by combined antibiotic and phosphocitrate therapy.

The potential of phosphocitrate to inhibit infection stones in rats when combined with an antibiotic was studied. A significant reduction occurred in both the number and weight of recovered stones from rats receiving combined treatment with amoxycillin (50 mg./kg. body wt./day and phosphocitrate (112 mumol./kg. body wt./day) for four weeks. The inhibitory responses were attributed to the intact phosphocitrate molecule as administration of citrate in equimolar concentrations did not mimic the observed effects of phosphocitrate. In comparison with non-infected controls, antibiotic treatment alone failed to eliminate total stone growth. However, composition of the stone reverted from predominantly struvite to a mixture of struvite and newberyite as urinary parameters normalized. The studies highlight the usefulness of phosphocitrate to restrict magnesium salt deposition in vivo.

Amoxicillin↗
PubMed1988

Complex struvite calculi treated by primary extracorporeal shock wave lithotripsy and chemolysis with hemiacidrin irrigation.

Ten patients with complex struvite stones were treated successfully with primary extracorporeal shock wave lithotripsy followed by chemolysis with 10 per cent hemiacidrin renal irrigation. The average number of treatments per renal unit was 1.2 and an average of 2,688 shocks was administered per treatment. No patient required a blood transfusion. Ureteral obstruction did not occur in those patients receiving planned hemiacidrin irrigation immediately after extracorporeal shock wave lithotripsy. At 6-week followup 9 patients were free of residual fragments. The combination of extracorporeal shock wave lithotripsy and hemiacidrin chemolysis represents a satisfactory alternative to the traditional surgical management of complex struvite calculi.

Adult↗
PubMed1988

Stone fragility--a new therapeutic distinction.

The ESWL retreatment rates for calculi of 1.1 to 3.0 cm. varied according to stone composition: calcium oxalate monohydrate (COM) 10.3%, calcium oxalate dihydrate (COD) 2.8%, struvite/apatite calculi 6.4%. Fine detail in-vitro radiographs of approximately equal sized calculi composed of COM, COD, struvite, brushite, uric acid and cystine showed structural differences which may account for differences in their fragility. The same six calculi were fragmented in vitro in the Dornier HM3 lithotriptor by 200 shocks at 18 KV and the percent weight of each calculus able to be filtered through a two mm. sieve was determined; COD and uric acid (100%); COM (64%); struvite (57%); brushite (47%); cystine (16%). The linear density of these calculi, measured by single photon emission absorbtiometry, correlated with radio-density, not fragility. Calculi of varying composition respond differently to shock wave fragmentation. The assessment of the capability of ESWL to fragment a stone will determine the size stone selected for treatment. Therefore, "stone fragility" is a new distinction which deserves to be included in the conversation about urinary calculi.

Calcium Oxalate↗
PubMed1987

The pulsed dye laser for fragmenting urinary calculi.

The properties of a laser which effect stone fragmentation have been studied. The pulsed dye laser emitting at 504 nm. in one microsecond duration pulses appears to be the optimum out of a wide range of parameters tested. The laser is coupled to a 200 micron core fiber; this complete with its cladding has a total diameter of only 0.25 mm. Most calculi are fragmented by a series of pulses of up to 30 mJ. The system is used by firing bursts of pulses with the fiber actually in contact with the stone. The result is a very controlled fragmentation which is particularly suited to use in the confines of the ureter. This modality of treatment utilises less energy than ultrasound or electrohydraulic probes to fragment a stone and the very fine, flexible fiber represents a considerable miniaturization.

Calcium Oxalate↗
PubMed1987

Outpatient irrigation of the renal collecting system with 10 per cent hemiacidrin: cumulative experience of 365 days in 13 patients.

Despite Food and Drug Administration restrictions on its use above the ureterovesical junction, many investigators have used carefully monitored renal pelvic lavage with 10 per cent hemiacidrin for struvite calculi without serious side effects in hospitalized patients. We evaluated renal irrigations with hemiacidrin in 13 carefully selected patients (15 kidneys). In this high risk population (6 patients were paretic) initial treatment was done in the hospital but the remainder of 18 periods of extended renal perfusion (mean period 20 days) were performed at home. The total number of outpatient days of perfusion in this group was 365. All patients experienced external leakage around the perfusion catheter. Fever of greater than 101F occurred in 14 of 18 perfusions (78 per cent). Rehospitalization was necessary during 3 perfusions (17 per cent) and serum magnesium was elevated 3 times (17 per cent). Stones were dissolved successfully in 14 of 18 perfusions (78 per cent) but they recurred in 3 patients. No patient had altered post-perfusion serum creatinine levels. Outpatient perfusion of the renal pelvis with 10 per cent hemiacidrin under carefully controlled conditions appears to be a safe and cost-effective treatment for struvite or phosphate renal calculi.

Adult↗
PubMed1987

Fluoride concentrations in a collection of urinary calculi.

Fluoride concentrations in 42 urinary calculi were determined using a microdiffusion procedure in conjunction with a fluoride sensitive electrode. Mean values of 56, 230 and 1112 ng./mg. fluoride were obtained for uric acid, calcium oxalate monohydrate and apatite/struvite stones, respectively. Fluoride concentration was found to be related to calcium oxalate dihydrate levels as well as to apatite content. It is suggested that the former has zeolithic properties which might trap fluoride while formation and growth of the latter appears to be enhanced by elevated urinary fluoride levels.

Apatites↗
PubMed1987

Formation of encrustations on indwelling urinary catheters in the elderly: a comparison of different types of catheter materials in "blockers" and "nonblockers".

In order to determine the effect of catheter materials on formation of encrustations in long-term indwelling urinary catheters in the elderly we performed a crossover study utilizing commercially available silicone, silicone-coated, teflon-coated and latex catheters that were left in place for 14 days. The study was conducted with #18 french catheters fitted with a 30 ml. balloon since smaller size catheters frequently fell out spontaneously. The distinction between patients who were "blockers" and "nonblockers" was found to be clinically useful since "nonblockers", who constituted about half the population, did well regardless of type of catheter material used. Formation of encrustations and blockage was significantly less in "blockers" with silicone than with teflon-coated or latex catheters. The more rapid flow-time through silicone catheters appears to be related to a larger bore. Although this study supports the use of silicone catheters for "blockers" on long-term drainage the results should not be interpreted to imply that they are preferable to other types of catheters for short-term use or to changing less expensive catheters more frequently when needed.

Aged↗
PubMed1987

Urolithogenesis of mixed foreign body stones.

Urine of male Sprague-Dawley rats was supersaturated for struvite and often contained struvite crystals. Ethylene glycol administration to these rats resulted in elevation of urinary oxalate and calcium oxalate supersaturation, and induced calcium oxalate crystalluria. Implantation of foreign bodies in their urinary bladders and changing their urinary ambient conditions by administering ethylene glycol for two weeks at two week intervals resulted in the formation of urinary stones of mixed composition containing calcium oxalate and struvite. Crystal-onto-crystal epitaxy did not appear to play any role in the development of these stones.

Animals↗
PubMed1987

gamma-Carboxyglutamic acid, a component in human pediatric bladder stones containing calcium salts.

The amino acid gamma-carboxyglutamic acid (Gla) has been previously detected in the vitamin K-requiring blood clotting factors, proteins of calcified vertebrate tissue, renal tissue, plasma protein C, ectopic calcifications, and calcium-containing renal calculi. This paper reports the presence of Gla in the EDTA-soluble, non-dialyzable material recovered from human pediatric bladder stones containing calcium salts. In bladder stones composed of calcium oxalate, uric acid and ammonium acid urate, 73 Gla residues per 1,000 amino acid residues were detected. Bladder stones composed of calcium oxalate, uric acid, ammonium acid urate, and hydroxyapatite contained 48 Gla residues per 1,000 amino acid residues present. No Gla was detected in the predominantly magnesium ammonium phosphate (struvite) bladder stones. These results with human bladder stones from children under 10 years of age are consistent with the observations from adult patients in which Gla was detected in the calcium-containing renal calculi but not in the non-calcium-containing renal calculi. The present study adds to the growing body of information concerning the possible role of Gla in normal and abnormal calcium metabolism.

1-Carboxyglutamic Acid↗
PubMed1986

Chronological variation in the chemical composition of upper urinary tract calculi.

From 1953 to 1984 upper urinary tract calculi obtained by operation or spontaneous discharge were analyzed by infrared spectroscopy. A review of the stone compositions for each 4-year interval from 1953 to 1984 showed a decreased incidence of magnesium ammonium phosphate-containing stones from 1961 and later. The incidence of these stones was approximately 20 per cent before 1960 and approximately 10 per cent after 1961, although the percentage increased again after 1973, especially in female patients. The decreased percentage after 1961 coincided with a decrease in the ratio of renal-to-ureteral stones. The development of antibiotics might have had an important role in the variation of stone compositions.

Adolescent↗
PubMed1986

Morphology of urinary stone particles resulting from ESWL treatment.

Fragments of urinary stones resulting from extracorporeal shock wave lithotripsy were examined by light and scanning electron microscopy. Calcium oxalate monohydrate and uric acid stone fragments were homogeneous and regular whereas struvite stone fragments were irregular in shape. Examination of the fractured surfaces revealed that the process of stone fragmentation involved fracture and cleavage of the crystals at some places and their separation from each other at others. In stones whose crystals are organised in layers, for instance calcium oxalate monohydrate and uric acid, crystalline layers separated along the concentric laminations. In struvite stones, which are an agglomeration of struvite and calcium phosphate crystals, major fragmentation occurred along the crystalline interfaces.

Calcium Oxalate↗