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PubMed1993

Role of magnesium as radiosensitizer in the in vitro radiolysis of aqueous solutions of guanosine-5'-monophosphate disodium.

A combination of Fourier Transform Infrared (FT-IR) spectroscopy and mass spectrometry (MS) was used to investigate the role of Mg2+ ions in gamma-radiolysis of aqueous solutions of guanosine-5'-monophosphate disodium salt. The FT-IR intensity changes together with the mass spectra suggest the interaction of the magnesium atom with the base guanine at the N7 site. The decomposition-limiting yield G(-5'-GMPNa2) in deaerated as well as in nitrous oxide saturated solutions, determined by measuring the absorbance at 253 nm, was found to be 0.6 and 1.2 respectively. Comparison of these values with the corresponding limiting yields of 0.3 and 0.6 that were found in the absence of Mg2+ ions shows the sensitizing role of this ion in the radiolysis of the mononucleotide. This in vitro behaviour may result in more effective local therapy of tumour by gamma-ray irradiation in the presence of Mg2+, due to the 100 per cent sensitization of the radiolysis reaction. It remains to be seen whether this is also true in vivo.

Cyclic GMP↗
PubMed1993

[The use of actapulgite for the treatment of acute diarrhea in infants and children. Review of pediatric studies].

Epidemiological data on diarrhea due to Rotavirus are similar enough across different regions of the world to allow the pooling of clinical studies of Actapulgite for the treatment of acute diarrhea in infants and children in France and Africa. A total of 7,616 infants and children were entered into these open or placebo-controlled trials. Most patients were under two years of age, results of the analysis confirmed the antidiarrheal efficacy and safety of Actapulgite.

Acute Disease↗
PubMed1996

Epizootiologic evaluation of urolithiasis in cats: 3,498 cases (1982-1992).

OBJECTIVE: to test the hypothesis that breed, sex and age of cats, and anatomic location of uroliths are risk factors for calcium oxalate and magnesium ammonium phosphate urolithiasis. DESIGN: Retrospective case-control study. SAMPLE POPULATION: Records of 3,498 feline urolith accessions submitted between September 1982 and September 1992. PROCEDURE: Mineral composition of feline uroliths was quantitatively analyzed. Odds ratios and 95% confidence intervals were calculated for breed, sex, age, and urolith location as risk factors for calcium oxalate and magnesium ammonium phosphate urolith formation. The population at risk was defined as all cats for which that type of urolith had been submitted. The control population was all cats for which uroliths had been submitted, excluding cats with the type of urolith being evaluated. RESULTS: Burmese, Persian, and Himalayan breeds were at higher risk for developing calcium oxalate uroliths, but at reduced risk for developing magnesium ammonium phosphate uroliths. Compared with females, neutered male cats had a higher risk for developing calcium oxalate uroliths, but a reduced risk for developing magnesium ammonium phosphate uroliths. The risk for calcium oxalate urolith formation increased with age. One- to 2-year-old female cats had the highest risk for magnesium ammonium phosphate uroliths. Uroliths removed from the kidneys were more likely to be composed of calcium oxalate than of magnesium ammonium phosphate. CLINICAL IMPLICATIONS: Breed, sex, and age of cats, and anatomic location of uroliths should be considered when evaluating risk of calcium oxalate and magnesium ammonium phosphate urolithiasis in urolith-forming cats.

Age Factors↗
PubMed1996

Influence of four diets on uric acid metabolism and endogenous acid production in healthy beagles.

OBJECTIVE: To evaluate the influence of 3 diets used to dissolve or prevent ammonium urate uroliths in dogs, and a diet formulated for growth, on 24-hour excretions of uric acid, ammonia, net acid, titratable acid, bicarbonate, and creatinine; 24-hour urine volumes; pH values of 24-hour urine samples; plasma uric acid concentration; serum creatinine concentration; and endogenous creatinine clearance values. DESIGN: Randomized block. ANIMALS: Six reproductively intact female Beagles, 3.9 to 4.2 years old, weighing 8.5 to 11.1 kg. PROCEDURES: Four diets were evaluated for their ability to dissolve magnesium ammonium phosphate hexahydrate (struvite) uroliths (diet S); to minimize uric acid excretion (diet U); to minimize clinical signs associated with renal failure (diet K); and to promote growth in pups (diet P). Each diet was fed for 14 days; then 24-hour urine samples were collected. An adult maintenance diet was fed during a 7-day washout period. RESULTS: Consumption of diet U was associated with lowest plasma uric acid concentration, lowest 24-hour urinary uric acid, ammonia, titratable acid, and net acid excretions, lowest endogenous creatinine clearance values, highest 24-hour urinary bicarbonate excretion and urine pH values, and highest 24-hour urine volumes. Consumption of diet P was associated with opposite results; results of consumption of diets S and K were intermediate between those for diets U and P. CONCLUSION: Consumption of diet U by healthy Beagles is associated with reduced magnitude of urinary excretion of uric acid and ammonia, with alkaluria, and with polyuria, which may be beneficial in the management of ammonium urate uroliths in dogs. CLINICAL RELEVANCE: Results support use of diet U for management of ammonium urate urolithiasis in dogs.

Ammonia↗
PubMed1996

Feline urolithiasis. Etiology and pathophysiology.

A variety of different types of uroliths occur in cats, of which calcium oxalate and magnesium ammonium phosphate are the most common. Treatment and prevention are most likely to be successful if associated risk factors are identified and eliminated or controlled.

Animals↗
PubMed1996

Feline urethral plugs. Etiology and pathophysiology.

Feline urethral plugs commonly are composed of large quantities of matrix mixed with minerals (especially struvite). However, some urethral plugs are composed primarily of matrix, some consist of sloughed tissue, blood, and/or inflammatory reactants, and a few are composed primarily of aggregates of crystalline minerals. The formation of matrix-crystalline urethral plugs may be analogous to the preparation of fruit jello.

Animals↗
PubMed1996

Ultrastructure of selected struvite-containing urinary calculi from cats.

OBJECTIVE: To elucidate the ultrastructural details of struvite-containing urinary calculi from cats. DESIGN: Specimens studied were inclusive of the range of textures visible during preliminary analysis by use of a stereoscopic dissecting microscope. Textural types, which were used to infer crystal growth conditions, were differentiated with regard to crystal habit, crystal size, growth orientation, and primary porosity. SAMPLE POPULATION: Thirty specimens were selected from a collection of approximately 1,600 feline urinary calculi: 20 of these were composed entirely of struvite, and 10 consisted of struvite and calcium phosphate (apatite). PROCEDURE: Qualitative and quantitative analyses of specimens included use of plain and polarized light microscopy, x-ray diffractometry, scanning electron microscopy with backscattered electron imagery, x-ray fluorescence scans, and electron probe microanalysis. RESULTS: Four textural types were recognized among struvite calculi, whereas 2 textural types of struvite-apatite calculi were described. CONCLUSIONS: The presence of minute, well interconnected primary pores in struvite-containing urinary calculi from cats is an important feature, which may promote possible interaction of calculi with changes in urine composition. CLINICAL RELEVANCE: Primary porosity, which can facilitate interaction between the calculus and changing urine composition, may explain the efficacy of dietary or medicinal manipulations to promote the dissolution of struvite-containing uroliths from this species.

Animals↗
PubMed1996

Struvite stones: long term follow up under metaphylaxis.

This study presents the results of a 10-year metaphylaxis of 19 former struvite stone formers, each having had 2-3 stone operations. In these patients, urine was acidified with L-methionine (Acimethin) using a dose of three to six tablets 500 mg/day. Every three months, 11 laboratory parameters were checked in 24-hour urine. 6 parameters were determined in serum. In addition, urine samples were tested for infection. Statistical analysis of analytical data, which was supported by computer graphs, provided the results for the urinary parameters. They were described by geometric means and 95% confidence intervals using ANOVA (analysis of variance). During therapy, the mean pH values decreased significantly from 7.5 to 5.5. Signific-ant increases were found in the excretion of citrate, magnesium, potassium, and uric acid. An increase was also found for calcium, which, however, could not be confirmed to be statistically significant (p = 0.08). In serum, changes of parameters could only be registered for calcium and phosphate. However, at all times, total serum concentrations stayed within their normal limits. Three patients suffered occasional infections (16%), only two of them formed recurrent stones (10%). In assessing the efficacy of L-methionine therapy, the drop in urinary pH to acidic values was the most relevant factor for metaphylaxis.

Analysis of Variance↗
PubMed1995

Influence of crystallization on strength and color of castable glass-ceramics containing two crystals.

The mechanical properties, color and transparency of glass-ceramics are highly dependent on the ceramming temperature and/or amount of the crystal phase in the glass matrix. In this study, the influence of crystallization on the strength and color, translucency of castable ceramics containing crystalline apatite and magnesium titanate were measured. It was concluded that magnesium titanate precipitated during ceramming, appeared to be an important factor in decreasing total transmittance and in determination of the color of glass-ceramics.

Apatites↗
PubMed1996

Ultrastructure of selected struvite-containing urinary calculi from dogs.

OBJECTIVE: To elucidate the ultrastructural details of struvite-containing urinary calculi from dogs. SAMPLE POPULATION: 38 specimens were selected from a collection of approximately 13,000 canine urinary calculi: 18 of these were composed entirely of struvite, and 20 consisted of struvite and calcium phosphate (apatite). PROCEDURE: Qualitative and quantitative analyses of specimens included use of plain and polarized light microscopy, x-ray diffractometry, scanning electron microscopy with backscattered electron imagery, x-ray fluorescence scans, and electron microprobe analysis. RESULTS: 4 textural types were recognized among struvite calculi, and 4 textural types of struvite-apatite calculi were described. Evidences of calculus dissolution were described from 4 calculi studied. CONCLUSIONS: The presence of small, well interconnected primary pores in struvite-containing urinary calculi from dogs appears to be a significant factor in determining the possible interaction of calculi with changes in the urine composition. The progress of dissolution from the calculus surface to the calculus interior appears to be largely affected by the primary porosity originally present between crystals forming the calculus framework. Apatite was observed to be more resistant to dissolution than struvite. CLINICAL RELEVANCE: The prevalence of fine concentric laminations having low porosity, and the common occurrence of apatite among struvite-containing urinary calculi from dogs may be 2 reasons why the efficacy of dietary and medicinal manipulations in dissolving urinary calculi is greater among cats than it is among dogs.

Animals↗
PubMed1996

Effects of a high-protein diet on mineral metabolism and struvite activity product in clinically normal cats.

OBJECTIVE: To examine effects of high-protein diets (> 50% crude protein of dry matter) on urinary mineral excretion and struvite activity product ([Mg2+] x [NH4+] x [PO(4)3-]). ANIMALS: 14 clinically normal cats, 4 adult female and male cats for experiments 1 and 2, respectively, and 6 female kittens aged 4 months for experiment 3. PROCEDURE: Relations between dietary protein amount (25.9, 38.3, 51.4, and 65.4% crude protein [dry matter]) and urinary excretion of Mg, P, and Ca were examined in a 4 x 4-Latin square design (experiment 1). Struvite activity product, the index of solubility of struvite crystals, was determined when a high-protein diet (54.9%) was fed (experiment 2). Utilization of minerals in cats fed a high-protein diet long term was examined (experiment 3). RESULTS: Water intake and urine volume increased with increasing dietary protein concentration. Urinary Mg2+ excretion was not affected (experiment 1) or was decreased (experiment 3) by higher protein intake, leading to lower urine Mg2+ concentration in groups fed higher protein amounts. Urine pH was decreased by high-protein intake. As a result, PO(4)3- concentration was decreased by high-protein intake (experiment 2), although total daily urinary excretion of P was increased. Consequently, struvite activity product tended to decrease in cats fed high-protein diets, indicating increase in struvite solubility. High-protein intake decreased Ca and P retention by increasing their fecal and urinary excretions, respectively. CONCLUSION: As a consequence of the increase in urine volume and urine acidification, high-protein diets have potential ability to increase solubility of struvite crystals.

Animals↗
PubMed1997

Clinical evaluation of cats with nonobstructive urinary tract diseases.

OBJECTIVE: To identify the underlying cause of clinical signs in cats with nonobstructive diseases of the bladder and urethra. DESIGN: Prospective case series. SAMPLE POPULATION: 109 cats examined by the urology service of The Ohio State University's veterinary teaching hospital because of stranguria, hematuria, pollakiuria, or urination in inappropriate locations. PROCEDURE: History was obtained and a CBC, serum biochemical analyses, serologic tests for FeLV and feline immunodeficiency virus, urinalysis, bacterial culture of urine, and contrast radiography or urethrocystoscopy (females only) were performed. RESULTS: 16 cats had cystic calculi: 8 had struvite uroliths, 7 had calcium oxalate uroliths, and 1 had a urolith of unknown composition in conjunction with an anatomic defect. Anatomic defects, including diverticulae, urethral strictures, and a malpositioned urethra, were identified in 12 cats. A urinary tract infection was identified in 1 cat, and neoplasia was diagnosed in 2. One of the cats with neoplasia also had a struvite urolith. The remaining 80 cats did not have an anatomic defect, urolith, or tumor. Ten of these cats also did not have radiographic or cystoscopic abnormalities and were presumed to have a behavioral disorder. The remaining 70 cats had radiographic or cystoscopic abnormalities, and idiopathic cystitis was diagnosed. In 14 of the cats with idiopathic cystitis, results of a urinalysis were normal. Cats with idiopathic cystitis were significantly more likely to eat dry food exclusively (59%) than were cats in the general population (19%). CLINICAL IMPLICATIONS: Results suggest that idiopathic cystitis occurs commonly in cats with stranguria, hematuria, pollakiuria, or inappropriate elimination and is associated with consumption of dry foods. Contrast radiography or cystoscopy is necessary for differentiating idiopathic cystitis from behavioral disorders in some cats.

Animal Feed↗
PubMed1996

[Salivary calculi. Apropos of 41 cases].

This retrospective study presents a clinical analysis of 41 patients with salivary gland calculi. Epidemiological, clinical, radiological, mineralogical and therapeutical aspects are presented and discussed. Surgical treatment is the most used but new technics of lithotripsy and/or ultrafine fibroscopy, which are more comfortable and less invasive, may reduce the surgical indications.

Adolescent↗
PubMed1997

Effects of choreito consumption on urine variables of healthy cats fed a magnesium-supplemented commercial diet.

OBJECTIVE: To investigate the effect of choreito consumption (500 mg/kg of body weight/d) on struvite crystal formation and signs of lower urinary tract disease (LUTD) in cats consuming a commercial canned diet with 0.5% added inorganic magnesium. SAMPLE POPULATION: 6 male and 6 female adult cats, all considered to be clinically normal on the basis of physical examination findings; results of CBC, serum biochemical analyses, urinalyses, and urine cultures; and freedom from urolithiasis on the basis of urethrocystoscopic (females) or urethrocystographic (males) findings. PROCEDURE: Diets were fed for 12 weeks, or until appearance of signs of LUTD, including dysuria, hematuria, urine pH > 7.0, and severe struvite crystalluria. Presence of at least 2 of these signs was required for removal from study. Urine specimens were examined for electrolytes, struvite crystal content, and hematuria. RESULTS: Results for urine variables were compared between groups at 4 weeks, because of reduction in cat numbers attributable to removal from study. Struvite crystal content of 24-hour urine specimens was significantly lower for cats fed the choreito-containing diet. Moreover, frequency and severity of hematuria were significantly decreased in cats fed the choreito-containing diet. Correlation between hematuria and struvite crystal content was not observed in either group. Additionally, all 6 cats fed the diet without choreito had been removed from study by day 58 because of signs of LUTD. Of the 6 cats fed the choreito-containing diet, 2 completed the 12-week study. CLINICAL RELEVANCE: Choreito may be beneficial for relief of some signs of struvite-associated LUTD disease in cats.

Analysis of Variance↗
PubMed1997

Effects of choreito and takushya consumption on in vitro and in vivo struvite solubility in cat urine.

OBJECTIVE: To determine the effects of the takushya portion of choreito, a traditional Chinese treatment for urolithiasis, on urine and struvite crystal variables in cats fed diets containing takushya. SAMPLE POPULATION: 6 male and 6 female adult cats, all considered to be clinically normal on the basis of physical examination findings, results of CBC, serum biochemical analyses, urinalyses, and urine cultures; and freedom from urolithiasis on the basis of urethrocystoscopic (females) or urethrocystographic (males) findings. PROCEDURE: Cats were fed a commercial canned diet supplemented with 0.1-mg of takushya/kg of body weight, or with 0.5 mg of choreito/kg. Diets were fed, using a Latin-square design, to 3 groups of 4 cats (2 male, 2 female) each for 2 weeks, followed by blood and 24-hour urine sample collections. RESULTS: Consumption of takushya, which comprises 20% by weight of choreito, was not associated with adverse effects in cats at the amounts provided during the period of study. Moreover, takushya was responsible for most of the effect of choreito consumption on reduction of urine pH, and approximately half its ability to reduce struvite crystal formation in cat urine. CLINICAL RELEVANCE: Alternative treatments for struvite urolithiasis in cats may be feasible.

Analysis of Variance↗
PubMedDate not supplied

Formulation of aspirin-magaldrate double-layer tablets: in vitro evaluation and cytoprotective activity in rats.

Double layer 325 mg oral aspirin tablets buffered with magaldrate antacid, 100, 150, 175 and 200 mg (F1, F2, F3 and F4, respectively) were prepared by direct compression. The new formulae were of remarkable hardness and friability. The tablets complied with the requirements of the acid neutralizing capacity, uniformity of dosage units, disintegration and dissolution tests (USP XXIII) for buffered aspirin tablets. The in vitro release pattern of F1 and F1 followed first order kinetics (r = 0.999), while F3 and F4 were released according to a zero order model (r = 0.993). Formulations F2, F3 and F4 as well as the marketed preparations, pure Aspro tablets (Acetylsalicylic acid 320 mg per tablet), or Ascriptin tablets (aspirin 325 mg plus 150 mg Maalox per tablet) were administered to fasted rats by gavage at doses that provided 400 mg aspirin kg-1 and the extent of the induced gastric damage was quantified 6 h later. Ascriptin, F3 and F4 preparations produced significantly less gastric damage (p < 0.05, n = 6) when compared with pure Aspro tablets. There was a clear dose-dependent decrease in the gastric damage following treatment with F2, F3 and F4 preparations, but there was no significant difference between the effects of F3 and F4 which were equipotent with Ascriptin.

Aluminum Hydroxide↗