Scanning Electron Microscopic Study of Effect of Various Agents on Urinary Crystal Morphology

Crystals seen in human urinary stones namely whewellite, weddellite, brushite, octocalcium phosphate, apatite, struvite and newberyite were grown in vitro in silica gel medium. The crystal growth medium was reproduced with addition of known inhibitors of crystallisation namely tartaric acid and citric acid and urine samples of stone patients and normal controls. The size and shape of the crystals were studied in the original setup and on addition of various agents as observed under the scanning electron microscope (SEM). The SEM appearance of crystals was uniformly reproducible. Addition of known inhibitors produced alteration of crystal habit and stunting of growth. Urine of stone patients produced changes in crystal appearance. Normal urine samples produced reduction in size of crystals and altered shapes. It is surmised from the observations that normal urine contains inhibitors of crystallisation and these are absent in the urine of certain stone formers

Infrared vibrational spectroscopy: a rapid and novel diagnostic and monitoring tool for cystinuria

Cystinuria is the commonest inherited cause of nephrolithiasis (~1% in adults; ~6% in children) and is the result of impaired cystine reabsorption in the renal proximal tubule. Cystine is poorly soluble in urine with a solubility of ~1 mM and can readily form microcrystals that lead to cystine stone formation, especially at low urine pH. Diagnosis of cystinuria is made typically by ion-exchange chromatography (IEC) detection and quantitation, which is slow, laboursome and costly. More rapid and frequent monitoring of urinary cystine concentration would significantly improve the diagnosis and clinical management of cystinuria. We used attenuated total reflection - Fourier transform infrared spectroscopy (ATR-FTIR) to detect and quantitate insoluble cystine in 22 cystinuric and 5 healthy control urine samples. Creatinine concentration was also determined by ATR-FTIR to adjust for urinary concentration/dilution. Urine was centrifuged, the insoluble fraction re-suspended in 5 μL water and dried on the ATR prism. Cystine was quantitated using its 1296 cm−1 absorption band and levels matched with parallel measurements made using IEC. ATR-FTIR afforded a rapid and inexpensive method of detecting and quantitating insoluble urinary cystine. This proof-of-concept study provides a basis for developing a high-throughput, cost-effective diagnostic method for cystinuria, and for point-of-care clinical monitoring

Efficacy of contemporary and novel intracanal medicaments against Enterococcus faecalis

Objectives. To compare the antibacterial activity of propolis (30% in methyl cellulose), curcumin (2.5mg/mL of methyl cellulose), 2% chlorhexidine gel (CHX), 2% metronidazole gel (MZ) and a mixture of 2% CHX and 2% MZ against Enterococcus faecalis in vitro. Calcium hydroxide served as the control. Study design. The inhibitory effect of the medicaments on E. Faecalis was determined by the agar diffusion test and tube dilution test.The rate of bactericidal activity was evaluated by the time-kill assay. Zones of inhibition data and time to kill data were statistically analyzed by ANOVA and post hoc Tukey test (P=0.05). Results. CHX demonstrated the highest mean zone of inhibition (34 ± 3mm) which was not significantly different (P>0.05) from curcumin (33 ± 2mm) and MZ (30 ± 2mm). Calcium hydroxide showed only contact inhibition. The time kill assay showed a time dependent action of each medicament. Conclusions. All tested agents except calcium hydroxide demonstrated significant reduction of viable bacteria at the time periods. The intracanal medicaments tested brought about a time dependent antibacterial effect on E.faecalis.Link_to_subscribed_fulltex