Physiological and biochemical properties of neuromuscular transmission between identified motoneurons and gill muscle in Aplysia.
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Acetylcholine↗
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Motor control of buccal muscles in Aplysia.
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Acetylcholine↗
A study of struvite precipitation and urease activity in bacteria isolated from patients with urinary infections and their possible involvement in the formation of renal calculi.
Struvite precipitation and urease activity were studied in 72 bacterial strains isolated from patients with an urinary infection. The results revealed struvite precipitation by urease-positive, urease-negative and weakly urealitic bacteria. However, in some strains of each of these groups, no precipitation was observed. Variations in pH within the cultures were also investigated as were the mineralogy and morphology of the crystals precipitated using X-ray diffraction and scanning electron microscopy, respectively. The role of urease activity and alkalinization of the medium in struvite precipitation is discussed, as is the possible involvement of bacteria in nucleation processes. We concluded that urease-negative bacteria or those with weak urease activity may also be involved in the formation of struvite renal calculi although urease-positive bacteria seem to make a greater contribution.
Chemical Precipitation↗
Management of staghorn calculus: analysis of combination therapy and open surgery.
OBJECTIVE: To assess the role of primary open surgery versus the recommended combination approach (percutaneous and lithotripsy) to treat staghorn calculi in a developing country. PATIENTS AND METHODS: Available records (n = 91) of patients with staghorn managed during the last 4 years were retrieved. Patients were placed in two groups, open surgery and combination group, according to the primary procedure chosen by the patient. Demographic data in two groups was comparable in most of the respects except that renal failure patients were more in the combination group. Stone clearance, major residue, auxiliary procedures, morbidity, hospital stay and the cost were studied in the two groups for comparison. RESULTS: Complete clearance could be obtained in 66 and 59% with open and combination method respectively. Major residue (> 16 mm2) was present in 21% of open and 38% of the combination group. In patients with primary stone burden < 900 mm2, the total clearance rates were 66 and 60% in open and combination group, respectively. Total clearance was not affected by caliceal dilatation, total stone burden, pelvic and caliceal bulk separately or their ratio, as arrived by logistic regression analysis. The incidence of haematuria in the combination group was marginally higher, probably due to more renal failure patients in this group. Hospital stay in the two groups was comparable (13.0 days in combination vs. 12.1 days for open). The cost of treatment with combination group was significantly higher. CONCLUSION: Open surgery for staghorn is still an economically viable option for difficult stone disease, specially in a developing country, with comparable efficacy, favourable morbidity and hospital stay.
Adult↗
Struvite stones.
Struvite stones constitute only about 2-3% of the stones reaching the laboratory for analysis, but the clinical problems they create including sepsis and even renal demise are greater than with any other stone type. This article reviews the evidence that bacterial urease, usually from a Proteus species, is responsible for the chemical changes in urine which result in struvite formation. Available urease inhibitors and other forms of medical management of patients with these stones are discussed. A patient with struvite stones should be assumed to have a progressive disease which cannot be ignored. Even after seemingly successful elimination of stones with lithotripsy and/or percutaneous nephrolithotomy, careful medical follow-up is critical. The medical profession is probably underutilizing postprocedure hemiacidrin irrigation because of shortsighted financial considerations. Primary-care physicians need to be educated in the importance of aggressive management of Proteus and other urea-splitting infections.
Adult↗
Crystal structures of calcium orthophosphates.
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Apatites↗
Chemolitholysis and lithotripsy of infectious urinary stones - an in vitro study.
OBJECTIVES: This study was performed to look for an improvement of therapeutic strategies with regard to the treatment of infectious urinary stones using artificial stones made of struvite and apatite ('Bon(n) stones') which are comparable to their natural counterparts. MATERIALS AND METHODS: Using an experimental arrangement simulating the physiological conditions in the upper urinary tract, the efficacy of artificial urine (pH 5.7), Suby G solution (pH 3.6), mixtures of artificial urine with Suby G (pH 3.9 and pH 4.1) in dissolving artificial struvite and apatite stones (Bon(n) stones) was investigated. The dissolution of natural infectious urinary stones was also measured. Additionally, investigations on shock-wave lithotripsy (SWL) combined with initial chemolytic treatment of the stones were performed. RESULTS: The efficacy of Suby G solution in dissolving artificial stones was demonstrated. Direct comparison of chemolysis of natural and artificial stones showed no statistical difference between infectious urinary stones and Bon(n) stones of the same material. The investigations on SWL showed a significant improvement on stone comminution, especially of artificial apatite stones after initial chemolytic treatment with Suby G. CONCLUSION: New basics to improve dissolution of infectious urinary stones have been developed by performing standardized in vitro investigations. Local chemolysis with Suby G is an effective tool in the treatment of infectious stone disease. SWL can be improved by varying the physical properties of infectious stones through initial treatment with Suby G solution.
Apatites↗
Cellular and molecular gateways to urolithiasis: a new insight.
Urolithiasis is a relevant clinical problem in everyday practice with a subsequent burden for the health system. Urolithiasis is classically explained as the derangement in the process of biomineralization involving the equilibrium between promoters and inhibitors of crystallization: a deficit of one or several inhibitors or an excess of one or several promoters plays a pivotal role in the stone formation. The revolutionary introduction of the molecular biology in medicine has given a new insight in urolithiasis too. Genetic factors have also been postulated to play an important role. A review of the current knowledge on urolithiasis based upon a molecular and genetic approach is reported.
Animals↗
Effect of chronic administration of ammonium sulfate on phosphatic stone recurrence.
Urine alkalinization favours the formation of calcium phosphate (CaP) and struvite stones. In this retrospective study we analyze the effect of chronic urinary acidification on phosphatic stone recurrence. Twenty-four patients with CaP-struvite recurrent stones and persistently high urinary pH were divided in two groups: group A, 11 patients who failed to lower the urinary pH below 5.5 during a standard acid load test: group B, 13 patients with preserved acidification power. Ammonium sulfate 2-3 g/day was given for 4.7 and 6.5 years to groups A and B, respectively. A persistent reduction in urinary pH, relative saturation for CaP and stone formation rate was observed in both groups. The treatment did not cause systemic acidosis as long as renal function remained normal. Urinary daily excretion of Ca and P as well as their renal tubular handling did not change with time. Results suggest acidifying agents might be useful in preventing recurrence of CaP-struvite stones even in the presence of a mild acidification defect and encourage undertaking properly controlled prospective trials.
Adult↗
Hypertension in kidney stone patients.
The prevalence of arterial hypertension (HT) was investigated in 258 patients (171 m, 87 f, 22-68 years) with a history of primary stone disease. HT was detected in 64 patients (24.8%), with no difference between males (25.7%) and females (23.0%). The prevalence of HT by age was very similar to that of a general population, especially in the calcium stone group. The discriminant analysis demonstrated that the composition of stones, other than the age and body weight of the patients, were the main factors associated with HT. As far as the different kind of stone is concerned, the prevalence of HT was higher in patients with uric acid (17/37, 45.9%) and struvite stones (11/27, 40.7%) than in calcium stone formers (35/188, 18.6%) (chi 2 16.31, p < 0.001). The prevalence of hypercalciuria was higher in the calcium stone group than in uric acid or struvite stone patients (36.4 vs. 9.7 vs. 13.7%; chi 2 10.35, p < 0.01). Furthermore, the hypercalciuria showed a trend to be more prevalent in the untreated (47.0%) than in the treated (31.2%) hypertensives, or normotensives (35.1%). Uric acid stone formers were older, heavier and with higher triglycerides and uric acid plasma levels than calcium or struvite patients. Also the struvite stone formers were older than the calcium stone ones. Our data suggest that the prevalence of HT in kidney stone patients and particularly in calcium stone formers is similar to that of a general population. The role of hypercalciuria as the link for HT-urolithiasis association seems quite uncertain. Struvite and uric acid stone formers have higher risk for HT than calcium stone formers, probably due to the old age or to the associated metabolic abnormalities.
Adult↗
Effect of estrogen on the formation of struvite calculi in female rats.
The administration of 1 mg estradiol every other week for 12 weeks to female rats resulted in a high incidence (about 50%) of bladder stones. Most calculi were struvite, suggesting the predisposition to urinary tract infection. Enterobacteria, staphylococcus and streptococcus were identified as infecting organisms. Metaplasia of the transitional bladder epithelium by estrogen to a stratified or pseudostratified columnar epithelium may be involved in the underlying cause of urinary tract infection.
Animals↗
Formation of bobierrite (magnesium phosphate) crystal aggregates by bacteria from human urine and renal calculi.
The formation of extracellular crystal aggregates of bobierrite [Mg3(PO4)2.8H2O] by bacteria isolated from renal calculi and urine of urolithiasic patients is found with the use of B-17 and B-43 media. The crystal aggregates were observed in the colonies as deposits of brown-yellow coloration, and were identified by X-ray powder diffraction, chemical analysis and scanning electron microscopy. The production of bobierrite by bacteria from human urine and renal calculi implies further versatility of crystal formation by microorganisms, and it may be interesting to investigate the possible relationships between calculi precipitation and urinary infection.
Bacteria↗
ESWL monotherapy for large stones and staghorn calculi.
From December 1986 through March 1988, 52 renal units (RU) with large stone burden have been treated by ESWL monotherapy. In all patients a ureteral stent was placed prior to lithotripsy, to provide drainage of the kidney during the period of stone passage. Data of 43 RU were collected for the present report. Complications ; following treatment were infrequent (2%), whereas auxiliary measures became necessary in 32% of the patients. After a mean follow-up of 9.1 months, 54% of the patients were found stone-free. Stratification according to different stone types and compositions revealed that none of the 7 patients with complete staghorns could be completely cleared and that struvite stones had a significantly better outcome than calcium oxalate stones (75 vs. 25%). Consequently, for a large but not excessive stone burden in a normal or only slightly dilated renal collecting system, ESWL monotherapy under the protection of a ureteral stent may be a comparably safe alternative to percutaneous surgery.
Adult↗
Epidemiology of urolithiasis in Japan: a chronological and geographical study.
A nationwide survey on urolithiasis in Japan between 1965 through 1987 was carried out, succeeding the previous 1955 and 1966 studies, in an effort to evaluate chronological and geographical changes in urolithiasis among the Japanese people who are relatively racially homogenous and living with similar customs and habits, which have changed dramatically from the old Japanese to westernized modes in a very short period after the Second World War. Incidence of calcium-containing urinary stones in the upper urinary tract has been increasing in Japan since the Second World War with increasing westernization of life-style and industrialization, with the annual incidence of urolithiasis steadily increasing from 53.8/100,000 general population in 1965 to 92.5 in 1985. According to the data, 5.4% of the population may be expected to develop a urinary calculus at least once in their life time. Analysis of 69,949 stones obtained during the years from 1978 to 1987 with infrared analysis showed that 79.4% were calcium oxalate and/or calcium phosphate stones, 7.4% were struvite with or without carbonate apatite, 5.2% were uric acid or urate, and 1.0% were cystine. In the era of new treatment modalities such as the endourological surgery and the extracorporeal shock wave lithotripsy, open surgical treatments were replaced with new types of treatment in about 75% of the cases in 1985.
Calcium↗
Precipitation of struvite in urine medium by urease-positive and urease-negative Yersinia strains.
Yersinia strains either urease-positive or urease-negative were examined for precipitation of struvite in human urine at 25 and 37 degrees C. All urease-positive strains and 8 out of 10 urease-negative strains showed the ability to produce these crystals. Incubation time required for precipitation was longer for urease-negative strains and quantity of struvite formed was higher in urease-positive ones. Regarding incubation temperature, no significant influence has been observed.
Humans↗
Spontaneous passage of upper urinary tract calculi in relation to composition.
The composition of 2,755 calculi obtained from the upper urinary tract (1,409 by spontaneous passage and 1,346 by urological procedures) was analyzed using an infrared spectrophotometer, and the spontaneous passage rate was investigated in relation to the composition as well as other variables, such as stone size, and patient age and sex. Mixed stones of calcium oxalate and calcium phosphate were most frequently found, followed by those of calcium oxalate. The mean size (the maximum diameter) was largest in struvite stones and smallest in calcium oxalate ones. The sizes of stones from women were significantly larger than those from men (p < 0.01). As expected, the stone passage rates were inversely related to increasing stone size. The size of 55.6% of the stones passed was < or = 5 mm, and that of 96.6% of the stones < or = 10 mm.
Adolescent↗
Chemical compositions of 300 lower urinary tract calculi and associated disorders in the urinary tract.
The stones removed from 273 patients (220 males, 53 females) with bladder stones and 27 patients with urethral stones (males) were analyzed by infrared spectroscopy. Of these stones 50.0% contained magnesium ammonium phosphate (MAP), 39.9% calcium (oxalate and/or phosphate), 9.4% uric acid (urate), and 0.7% cystine. The disorders associated with bladder stones were prostatic hyperplasia and cancer (47.8%), neurogenic bladder (11.8%), urethral stricture (3.6%) and so on in males, and neurogenic bladder (48.1%), after operation of uterus (29.0%), bladder cancer (5.7%) and so on in females. Urinary infections were complications in 59.3% of patients with MAP stones, 41.2% with urate stones and 20.0% with calcium stones. The most often isolated bacteria from the infected urine were of the Proteus species.
Adolescent↗
Study of the structure of struvite stones with scanning electron microscopy and energy-dispersive X-ray microanalysis.
Topographic features of eight struvite calculi were investigated with scanning electron microscopy (SEM) equipped with energy-dispersive X-ray microanalysis (EDX). Perpendicularly cracked fragments showed concentric laminations composed of compact and loosely packed strata alternately. Magnesium and phosphorus were detected in the compact strata with their characteristic dispersive X-ray spectra. There existed numerous spherular crystals with smooth or porous surfaces and scattered penta- or hexa-hedral coffin-lid shaped crystals in the loosely packed strata. The former crystals showed the dispersive X-ray spectra of calcium and phosphorus, and were estimated to be calcium phosphate (CaP). The latter ones were presumed to be magnesium ammonium phosphate (MAP) with EDX. The surfaces of the fragments were cracked like eggshells and displayed numerous CaP crystals and scattered MAP crystals in most cases, while in only 1 case some faces of pieces demonstrated wavy MAP phases, sundry areas which were rimmed with aggregated CaP spherulites. The mean molar ratios of Mg/P and Ca/P in each case were 0.88-1.03 and 1.25-1.52, respectively. Though EDX was inadequate to determine the accurate chemical formula of CaP and MAP crystals by detecting their molar ratios of Ca/P and Mg/P with EDX, SEM/EDX is useful to observe these urolith crystals and to surmise them to be CaP or MAP crystals by detecting their atomic elements with EDX.
Adult↗