Urinary tubular enzyme excretion in children with nephrolithiasis and urolithiasis with hydronephrosis

Objective: Nephrolithiasis and urolithiasis are recurrent conditions associated with significant morbidity and economilc impact. Previous studies have suggested that cell- crystal interactions lead to tubular damage and/or dysfunction. To find further proof for these observations, a metabolic evaluation [including serum and urine biochemistry and urinary enzyme excretion] was done in children with nephrolithiasis and urolithiasis with hydronephrosis

Patients and Methods: This study included two groups: 10 normal children [controls] and 32 children with calcium oxalate urinary tract stones. The latter group was further subdivided into those with nephrolithiasis [n=12] and urolithiasis with hydronephrosis [n=20]. Levels of uric acid, oxalate, calcium, magnesium and inorganic phosphorus in 24-hour urine and serum were determined. Urinary N-acetyl-beta-D-glucosaminidase [NAG], beta-galactosidase [beta-GAL], beta-hexosaminidase [beta-Hex], angiotensin converting enzyme [ACE] and gamma glutamyl transferase [y-GT] levels were also determined colorimetrically

Results: Increases in urinary excretion of oxalate, calcium, magnesium and inorganic phosphorus were the major abnormalities found in stone forming patients. Elevated urinary NAG, beta-GAL, beta-Hex and ACE levels were also noted in patients compared with controls. Urinary excretion of oxalate, NAG, beta-GAL and ACE was significantly elevated in children with nephrolithiasis compared to those with urolithiasis and hydronephrosis

Conclusion: Abnormal urine biochemistry seems to have a role in the risk for urinary-tract stone formation in children. Hyperoxaluria can induce tubular cell injury mainly in proximal tubules, which is more pronounced in children with nephrolithiasis. The tubular injury manifested by enzymuria occurs before alteration of renal functions and blood biochemistry. Urinary tubular enzymes should be screened in children with urinary tract stones

MS-MS tandem mass spectrometeric studies of some nitropyridyl substituted phenyl ether derivatives

Nitro substituted pyridyl sulfide and amine derivatives were found to exhibit many fragmentation mechanisms a behaviour which is due to the high reactivity of nitropyridyl, nitro heterocyclic and nitro aromatic compounds. The most common mechanism in nitropyridyl derivatives is the ring closure through expulsion of nitrous acid molecule either by elimination of hydrogen and nitro radicals in two steps or a concerted mechanisms. Moreover, the elimination of nitrous acid molecule may occure via skeletal rearrangement of the molecular ion followed by successive loss of hydride and nitroside radicals to form a cyclic fragment. These mechanisms showed the importance of ortho effect, which favours the elimination of HNO2 molecule from the molecular ion. These mechanisms of ring closure could be confirmed on the basis of studied fragmentation processes by tandem mass spectrometry. It is usually used to propose the fragmentations pathways by following up the mass spectra produced from each individual ion

Kinetics of the reactions of 2,4-dinitrophenyl aryl sulphides sulphoxides and sulphones with hydroxide ion in 80 % [v/v] ethanol-water

The effect of substituent for the reactions of 2,4-dinitrophenyl aryl sulphoxide [la], sulphones [2a-i] and sulphides [3a-h] with hydroxide ion in 80% ethanol-water [v/v] at 25C was investigated. The relative mobility of thioaryl, sulfinylphenyl and sulfonyl aryl leaving groups was also discussed

Kinetics of the reactions of methyl-2,3-dibromo-3- [4-substituted phenyl] propanoates with piperidine IV

The rates of elimination of a series of erythromethyl- 2,3-dibromo-3-[4-substituted phenyl] propanoates [1 alpha-d] have been determined conductimetrically in methanol using piperidine as a base. The elimination reactions gave exclusively Z-methyl-2-bromo-3- [4-substituted phenyl] propanoates [2 alpha-d]. The specific rate constants of the reactions gave a good Hammett correlation with p values of 0.39-1.31 which suggest a carbonionic transition state. The results suggested that the reaction proceeds by initial isomerization of the erythro-dibromo-compound to the threo-isomer, which spontaneously eliminates HBr to give [2 alpha-d]

Stereochemistry of the reaction of primary amenies and hydrazine tives with activated alkynes

The reaction of methyl 3-[4-substituted phenyl]-propynoates I a, b and 3-[4-chlorophenyl]-1-phenyl-2-propyn-1-one II with 2-pyridylmethylamine III in methanol gave the corresponding E- and Z-enamine derivatives, respectively. The reaction of II with 4-amino-5-mercapto-3-methyl-1, 2, 4-triazole IV yielded a mixture of E, Z-enamine and imine derivatives. PMR and IR spectra confirmed the configuration assigned to the enamine products. Treatment of II with 2-hydrazinobenzothiazole V gave a mixture of the hydrazone and pyrazole derivatives