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Biomedical subjects

O Bianco

Publications and source records attributed to O Bianco.

14 recordsLinked to original sources
PubMed1991

Glycolate determination detects type I primary hyperoxaluria in dialysis patients.

The detection of type I primary hyperoxaluria is based on the finding of exceedingly high oxalate excretion which is associated with increased glycolate excretion. The differential diagnosis of this disease may become a difficult task once end-stage renal disease (ESRD) and anuria have supervened. The various procedures thus far proposed to obviate this circumstance are complex, inaccurate or not reproducible. In this paper we propose the accurate liquid chromatographic determination of glycolate in blood and dialysate as a means to detect type I primary hyperoxaluria in patients on maintenance hemodialysis (RDT). The method is based on the enzymatic conversion of glycolate to glyoxylate coupled with alpha-keto acid derivatization with phenylhydrazine. The resulting phenylhydrazone is then resolved by high-performance liquid chromatograph (HPLC). With this method, plasma glycolate in 12 healthy controls was 7.8 +/- 1.7 mumol/liter, almost twentyfold less than previously reported. Five dialysis patients with high serum oxalate, of whom four with primary hyperoxaluria and one with Crohn's disease and presumed enteric oxalate hyperabsorption, were checked by this method and compared to nine patients with oxalosis-unrelated ESRD. The patients with hyperoxalemia were also evaluated for their response to pyridoxine therapy. The measurement of glycolate in blood drawn prior to and at the end of the dialysis session as well as in the dialysate soundly discriminated the patients with type I hyperoxaluria from all the other dialysis patients. Glycolate measurement was shown to be much more powerful than oxalate in that patients with oxalosis-induced ESRD exhibited an almost two hundred and fiftyfold increase compared to the oxalosis-unrelated patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Ion-chromatographic determination of L-tartrate in urine samples.

We propose using ion chromatography to determine tartrate concentration in urine. A 100-microL sample of urine is diluted and injected into the chromatograph. Tartrate is eluted within 11.5 min as a distinct and well-resolved peak. The sensitivity of the standard procedure (signal-to-noise ratio, 3/1) is 30 mumol/L. The intra-run and interrun coefficients of variation are 2.5% and 4.1%, respectively. Mean analytical recovery of known amounts of added tartrate ranges between 94.2% and 104.0%. We investigated the specificity of the procedure by analyzing urine containing added dicarboxylic acids structurally related to tartrate. The reliability of the procedure makes it suitable for investigating tartrate metabolism, e.g., the potential role of tartrate as an inhibitor of crystallization in calcium nephrolithiasis.

Adult↗
PubMed1990

Ion chromatographic determination of plasma oxalate in healthy subjects, in patients with chronic renal failure and in cases of hyperoxaluric syndromes.

An ion chromatographic procedure for the determination of plasma oxalate is proposed, in which the ultrafiltered sample is injected into an ion-chromatographic system. Sample processing appears effective in avoiding spontaneous oxalogenesis. Sensitivity (down to 1.0 mumol/l) allows determinations in normal and pathological samples; recoveries from plasma ultrafiltration are 94.6 +/- 11.7%. Protein binding was investigated and precautions to improve recoveries from plasma ultrafiltration are proposed. The technique is simple to perform from healthy controls averaged 6.75 +/- 2.62 mumols/l (mean +/- S.D. n = 18); samples from patients with primary hyperoxaluria and chronic renal failure undergoing regular dialysis were also analysed and some of the data obtained are reported and discussed.

Adult↗
PubMed1990

Preventing ascorbate interference in ion-chromatographic determinations of urinary oxalate: four methods compared.

In an attempt to decrease ascorbate interference on the ion-chromatographic determination of urinary oxalate, we compared the effectiveness of four different methods for ascorbate elimination by analyzing a representative urine pool supplemented with successive ascorbate additions. Two of the methods--treatment with ferric ions or boric acid--have been described elsewhere; treatments with nitrites or ascorbate oxidase (EC 1.10.3.3) are investigated here as possible alternatives. Consideration of the main features, advantages, and drawbacks of the four procedures leads us to conclude that boric acid dilution is a good routine method and that pre-incubation with ascorbate oxidase reliably prevents ascorbate interference in assays of urinary oxalate.

Adult↗
PubMed1989

Derivatization and high-performance liquid chromatographic determination of urinary glycolic acid.

A high-performance liquid chromatographic method for the determination of urinary glycolic acid is proposed, based on pre-column derivatization with phenylhydrazine coupled with the enzymatic oxidation of glycolate to glyoxylate. The phenylhydrazone formed is separated by liquid chromatography and detected at 324 nm. The minimum detectable concentration of glycolate was 10.0 mumol/l. The recovery of glycolate added to urine averaged 96.1%. The day-to-day coefficients of variation calculated by analysis of two urine samples with normal and high glycolate contents were 4.6 and 7.5%, respectively. Results of analyses of urine samples from healthy persons, idiopathic calcium stone formers and Type I primary hyperoxaluria patients are reported.

Chromatography, High Pressure Liquid↗
PubMed1989

Effect of animal and vegetable protein intake on oxalate excretion in idiopathic calcium stone disease.

Oxalate excretion was measured in healthy subjects and idiopathic calcium stone-formers on dietary regimens which differed in the type and amount of protein allowed; 24-h urine collections were obtained from 41 practising vegetarians and 40 normal persons on a free, mixed, "mediterranean" diet. Twenty idiopathic calcium stone-formers were also studied while on two low calcium, low oxalate diets which differed in that animal protein was high in one and restricted in the other. Vegetarians had higher urinary oxalate levels than controls and although the calcium levels were markedly lower, urinary saturation with calcium/oxalate was significantly higher. This mild hypercalciuria was interpreted as being secondary to both a higher intake and increased fractional intestinal absorption of oxalate. Changing calcium stone-formers from a high to a low animal protein intake produced a significant decrease in calcium excretion but there was no variation in urinary oxalate. As a result, the decrease in calcium oxalate saturation was only marginal and not significant. It was concluded that dietary animal protein has a minimal effect on oxalate excretion. Mild hyperoxaluria of idiopathic calcium stone disease is likely to be intestinal in origin. Calcium stone-formers should be advised to avoid an excess of animal protein but the risks of a vegetable-rich diet should also be borne in mind.

Adult↗
PubMed1988

High-performance liquid chromatographic determination of glyoxylic acid in urine.

A high-performance liquid chromatographic (HPLC) method for the determination of urinary glyoxylic acid is proposed. The system is based on the precolumn derivatization of alpha-keto acids by means of phenylhydrazine, separation of the phenylhydrazone formed by HPLC and spectrophotometric detection at 324 nm. The method is precise and allows the determination of 0.5 mumol/l glyoxylate. The poor stability of glyoxylate under all conventional preservation conditions requires the analysis to be carried out as soon as possible after urine collection. Results of determinations on urine samples from healthy controls and from patients with idiopathic calcium stone disease and type I primary hyperoxaluria are reported.

Chromatography, High Pressure Liquid↗
PubMed1987

Acute renal failure in preeclampsia-eclampsia.

Acute renal failure (ARF) is regarded as relatively uncommon in preeclampsia-eclampsia (PE-E) and, in any event, of moderate degree or reversible. Cortical necrosis is reported as rare, even in fatal cases. Little light has as yet been shed on the mechanisms responsible for ARF in PE-E. This paper describes 17 cases observed over the last 15 years, in which cortical necrosis (3 histological and 2 clinical diagnoses) was relatively frequent (29.4%). The severity of renal impairment did not appear to be related to chronological age, parity, period of pregnancy in which PE-E commenced and its duration prior to delivery, presence of frank eclamptic crises or the concomitance of earlier vascular or renal disease (p greater than 0.05). The superimposition of abruptio placentae (AP) was the only clinical factor significantly correlated with cortical necrosis (p greater than 0.05). The association PE-E + AP seems to be a particularly unfavorable prognostic sign for the kidney owing to the contribution of additional damage mechanisms (vasospasm, disseminated intravascular coagulation, hemorrhagic shock) furnished by AP, while PE-E itself prepares the ground for AP. The fact that PE-E is difficult to diagnose when AP is the onset symptom may be responsible for the underestimation of its contribution towards the induction of severe renal damage.

Abruptio Placentae↗
PubMedDate not supplied

[Contribution of the serum anti-mycobacterial IgG measurement to the diagnosis of tuberculosis. Personal cases].

Data of a transversal research on 36 suspected tuberculosis (tb) inpatients of St. Luigi Hospital are reported. Serum antimycobacterial antibodies Class IgG to A60 were measured by means of ELISA. Final diagnosis was tb in 19 subjects, while 9 had a tb history over different years. Sensitivity was 78.94% and specificity 75%. According to with other recent reports, our results are poorly discriminating. However, the test, if valued with other clinical data, can contribute to the ascertainment of tb.

Adult↗
PubMedDate not supplied

[Mineral balance during hemodialysis and hemodiafiltration].

Keeping calcium (Ca) balance in equilibrium is one of the main goals in dialysis patients, and the dialysis schedule by itself can affect mineral metabolism. The aim of this paper is to evaluate Ca and magnesium (Mg) balances on different Quf in patients on RDT. Twenty-one patients [7 on hemodialysis (HD), 14 on hemodiafiltration (HDF)] were studied. Ca and Mg balances were assessed by measuring Ca and Mg in whole dialysis fluid. One patients on HDF was observed for three dialysis sessions, on different Quf, and negative values were observed for Quf above 70 ml/min. Mg balance was always negative. We conclude that an accurate survey of Ca balance is mandatory in high-efficiency dialysis, when high fluxes may produce adverse effects on mineral metabolism.

Calcium↗