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The urinary activity of 4 enzymes (NAG, GLU, GAL, GRS) was investigated in 105 healthy subjects in order to evaluate the variability of standard levels and establish the degree of such variations in relation to sex, age, weight and height. The results obtained demonstrate that these enzymurias do vary in relation to the parameters examined. Age and sex produced the most pronounced variations though height and body weight also appeared to have some influence. The study of variations in standard levels is of value in the interpretation of pathological enzymurias.

X-ray spectrophotometry shows undoubtful advantages versus conventional chemical methods employed in the analysis of kidney stones. In fact, it is possible to detect little crystals that are very important in the genesis and treatment of urinary calculosis.

Since a specific inhibition of cerebral spermidine (Spd) synthase activity by alicyclic amines was preliminarily observed in vitro, we examined the in vivo inhibitory effectiveness of dicyclohexylamine (DCHA) on Spd biosynthesis in 21-day-old rat brain. For this purpose a previously reported HPLC procedure (Porta et al., 1981a) was modified to analyze the cerebral levels of DCHA at the time of polyamine determinations. The intraperitoneally injected DCHA was shown to cross the blood-brain barrier easily, reaching high levels in the cerebral tissue (approximately 750 nmol/g brain) within 1 h of its administration. The effect of the drug on the polyamine metabolism resulted in a significant depletion of Spd biosynthesis from the sixth hour after the treatment and in an earlier and prolonged increase of the putrescine (Pt) steady-state levels. Conversely, the spermine (Spm) endogenous pools remained unchanged throughout the 24-h post-DCHA period. Moreover, following the intracerebral administration of [1,4-14C]Pt, significantly lower specific radioactivity (s.r.a.) values for labeled Pt and Spd were recorded in the brains of DCHA-treated animals. Conversely, after intracerebral [14C]Spd injection, the s.r.a. of newly formed [14C]Spm remained unchanged, confirming the specificity of the DCHA effect on the Spd biosynthesis.

Binding sites for [14C]spermine have been identified in rat brain cortex subcellular fractions. The binding, characterized by using synaptosomal membranes, is specific for spermine. It was not detected below 20 degrees C and increased about three/four-fold with a temperature rise of 10 degrees C. Binding occurred only in the presence of -SH reducing agents. It was completely suppressed by metal chelating agents, and was stimulated about four-fold by 1-5 x 10(-5) M Fe2+. Smaller increases were observed in the presence of Mn2+, Ni2+, Ca2+, Mg2+, and Zn2+; in contrast, millimolar concentrations of most divalent cations inhibited the binding differently (Mn2+ = Ni2+ = Zn2+ = Co2+ much greater than Mg2+ greater than Ca2+). Bound radioactive spermine was not displaced by the addition of high concentrations of unlabelled polyamine or chelating agents, nor by precipitation and washing of the membranes with 10 percent trichloroacetic acid, or by boiling of the precipitate in the presence of 1.0 percent SDS and 10 percent beta-mercaptoethanol. The trichloroacetic acid precipitate showed two radioactive bands, corresponding to low Mr (less than 8,000) components, after SDS-polyacrylamide gel electrophoresis and fluorography. The Fe2+-stimulated [14C]spermine binding was neither influenced by a previous heating of the membranes at 100 degrees C for 30 min nor by trypsin or pronase digestion, whereas the heat-treatment increased the binding occurring in the absence of Fe2+ by about two fold. A non-enzymatic formation of a spermine-metal complex tightly bound to some membrane peptide(s) is suggested.

The urinary activity of four enzymes (NAG, GLU, GRS and GAL) was studied in two groups of patients suffering respectively from interstitial nephritis and chronic glomerulonephritis with the aim of further investigating enzyme variability through the theory of partial and multiple correlation. This study permitted the effects of two enzymes on the known correlations between the remaining two enzyme types to be studied. It was established that very stable relationships exist between each enzyme and the group composed of the remaining three. In particular, in patients with interstizial nephritis, correlations with GAL were all highly significant even if the effect of the other two enzymes was ignored. Similarly, correlations with GRS were strongly significant in patients with chronic glomerulonephritis. In the two groups studied, each enzyme appears to have a highly stable relationship with the other three. Accurate estimates may probably be achieved for GAL and GRS in both groups and for NAG in the glomerulonephritis sufferers. This is further evidence that the enzyme procedure may be used to differentiate between interstitial and glomerular nephritis.

Three groups of subjects (I with infections of the lower urinary ways; II with chronic pyelonephritis; III healthy controls) were treated with pipemidic acid for 10 consecutive days and the behaviour of their urinary NAG and AAP was studied. It was discovered that the healthy group and the patients with infections of the lower urinary ways showed no significant variations in the urinary activity of the two enzymes following the administration of pipemidic acid. However there was a distinct reduction in both enzymes in patients with chronic pyelonephritis who presented demonstrable bacterial sensitivity to the drug. Apart from the fact that it produces no nephrotoxic effects at least in the doses used and for the treatment period adopted, the drug is therefore considered to reduce renal inflammation that is beneficial to individuals with chronic interstitial nephropathy.

105 healthy subjects were studied in order to verify results obtained on a smaller sample and revealed some correlations between NAG and GLU and age. It was also found that in male subjects, GAL tended to vary in relation to body weight and in females in relation to age.

A simple empirical method based on linear relation-ships between certain types of enzymuria (NAG, LDH, GRS, Isoenzymes I and V of total dehydrogenase lactate) has been used in a series of 80 patients presenting chronic nephropathy [40 interstitial nephropathy (IN) and 40 glomerulonephritis (GN)]. Diagnosis made on the basis of the results obtained in each case was identical to that based on clinical findings (in the absence of enzymuria determinations). This method, if confirmed on a larger number of statistically significant data, might be useful to obtain a differential diagnosis between I.N. and G.N. only assaying these few enzymurias. Prefixed relationships could be employed on a larger group of patients with other diseases studied for comparative purposes. Furthermore, this method appears to be fast and unexpensive.