Background/Aims: In end-stage renal disease (ESRD), hyperhomocysteinemia is a common finding associated with increased cardiovascular risk. However, the pathogenic role of homocysteine is still unclear. In vitro studies show that thiol redox status affects endothelial cell functions. We therefore investigated the possible association between homocysteinemia and plasma thiol redox status in ESRD patients. Methods: Total plasma homocysteine (Hcy), cysteine (Cys) and free thiols (SH) were measured both before and after a dialytic session in 54 ESRD patients receiving (n = 15) or not receiving (n = 39) folate supplementation, and 17 control subjects. Results: High predialysis levels of both Hcy and Cys were found to be negatively correlated with low SH levels both in supplemented (r = –0.680, p < 0.01 and r = –0.624, p < 0.02, respectively) and unsupplemented (r = –0.698, p < 0.001 and r = –0.445, p < 0.01, respectively) patients. Following dialysis, SH values returned to normal and the above correlations were no longer appreciable. Conclusion: A strong, folate therapy-insensitive association between homocysteinemia and plasma free thiol levels was found in ESRD patients. These results support a role for oxidative stress in ESRD-related hyperhomocysteinemia and suggest the plasma thiol redox status alteration as a possible pathogenic mechanism underlying the cardiovascular toxicity of hyperhomocysteinemia in these patients.

Background: Oxidative stress (OS) is considered to play a major role in the development of end-stage renal disease (ESRD) complications. However, conflicting and inconsistent data have been reported on OS in ESRD patients. Our aim was to investigate the reliability of the most popular non-enzymatic plasma OS biomarkers in ESRD.Methods: Vitamins A (VitA), E and C (VitC), uric acid, plasma antioxidant and ferric-reducing potential (PAP and PRP), thiols (SH), malondialdehyde (MDA) and lipid hydroperoxides (HPO) were determined before and after dialysis in plasma from 33 ESRD patients on hemodialysis, hemodiafiltration or peritoneal dialysis and 20 control subjects.Results: In ESRD patients, high PRP and normal PAP values were positively correlated with VitC levels. After dialysis, PRP levels decreased, while unchanged PAP levels correlated positively with high VitA and transiently recovered SH values. All patients showed high levels of both MDA and cholesterol-normalized HPO. However, while the former significantly decreased after dialysis, the latter were unaffected by treatment. Paradoxical correlations of MDA with both VitA and HPO were found.Conclusions: Plasma PRP and MDA levels may be dramatically affected by both uremia and dialysis; their use in ESRD patients may therefore lead to OS mis-evaluation and should be avoided. More reliable results can be obtained using physiologically relevant OS functional tests, such as PAP, and early biomarkers of OS damage, such as SH and HPO.

Aim. Common embryogenetic origins of the central nervous system and skin and its cutaneous adnexa offer a field of investigation to study the possible associations between neurological and dermatological disorders. Dementia of Alzheimer type (DAT) is a common neurodegenerative disease of unknown etiology presenting some cutaneous manifestations, (amyloid deposits, alterations in enzymatic activities and in fibroblast metabolism). A limited and insufficient number of studies have been focused on hair morphology in DAT. The aim of this paper is to search for an easily recognizable, accessible, biological marker for the diagnosis of DAT looking for peculiar abnormalities. Methods. Sample of hair from a group of patients with DAT and from a control group were studied by SEM and optic microscopy by a blind examiner. Apo E determination was also performed. Results. SEM and optic microscopy showed complete and/or uncomplete torsions and swellings of the hair shaft. The aminoacid analysis showed a reduction of cysteine levels and an increase of valine in 100% of subiects with Alzheimer's disease and in their healthy relatives. The determination of Apo E controlled by chromosome 19 underlined the importance of genetic factors even in the so called sporadic DAT. Conclusion. The occurrence of alterations cannot be interpreted as a preclinical marker in healthy individuals, but it has to be always investigated in the clinical and preclinical screening of affected patients and their relatives.

We have developed a high-performance liquid chromatographic-UV-Vis-diode-array detection (HPLC-DAD) method for the determination of ethyl-p-hydroxybenzoate, a hydrolytic degradation product of the synthetic protease inhibitor, gabexate-mesilate ethyl-p-(6-guanidinohexanoyloxy) benzoate methanesulfonate (GM) (FOY) in sow pancreatic juice. Methyl-p-hydroxybenzoate (I) was used as the internal standard. The pancreatic juice was deproteinised by acetonitrile and the analytes were chromatographed on a reversed-phase C18 LC column using the gradient elution method. The mobile phase consisted of a solution of 0.017 M orthophosphoric acid and another solution of acetonitrile-water (80:20, v/v). The wavelength of detection was 237 nm. The limit of quantification of the method was 0.20 microM at a 9:1 signal-to-noise ratio. The overall intra- and inter-day accuracy (relative error, RE) ranged from 14.2 to 8.3% and from 13.3 to 9.8, respectively. The overall intra- and inter-day precision (relative standard deviation, RSD) ranged from 7.6 to 2.62% and from 6.7 to 3.1%, respectively. The method proved to be sensitive, specific, accurate and precise and was successfully used to determine the ethyl-p-hydroxybenzoate (II) in sow pancreatic juice.

We studied the activity of some enzymes directly involved in the endogenous antioxidative defense system: glutathione-peroxidase (GPX), glutathione s-transferase (GST) and superoxide dismutase (SOD). We have investigated the effects of selenium and vitamin E diet supplementation, in form of selenium-vitamin E enriched yeast, in Wistar rats that were undergone to surgical right nephrectomy and 30 minutes of hypoxia. Blood samples were tested for several parameters as glucose, cholesterol, etc. to assess the general health conditions. The protocol consisted of 3 groups of 25 Wistar rats: a control group, a pre-fed group and a post-fed group. The results showed a significative difference in the behaviour of azotemia, proteins and cholesterol. In the control group the activity rapidly increased, then the values decreased slowly and differently for each substance. The pre and post-fed group showed a pronounced increase after 48 h but the normal values are reached more rapidly. We observed an increase in the activity of the GPX and GST after surgical operation and ischemia, but the GPX in pre-fed group reached the normal value before the other groups.

Mazzarella, V.*; Splendiani, G.; Tozzo, C.; Manni, M.°; R-Colombo, °; Severini, G.9; Caiola, S.*; Fortnnato, L.; Zazzaro, D.; Casciani, C. U. Author Information

The influence of uremic middle molecules on in vitro lymphocyte blast transformation and interleukin-2 production was studied in 12 patients on long-term hemodialysis and 12 healthy control subjects with normal kidney function. Middle molecules inhibit phytohemoagglutinin induced lymphocyte proliferation in a concentration dependent fashion, achieving more than 50% inhibition of tritiated thymidine incorporation after 72 hrs in culture. In addition, there was less interleukin-2 production in the long-term hemodialysis patients studied compared with healthy control subjects.

N-Acetyl-beta-glucosaminidase (NAG) and beta-glucuronidase were measured in the serum of 70 patients with breast and digestive-tract neoplasms and in 70 healthy subjects. The mean value of the NAG activity was significantly (P < 0.001) elevated in patients with gastric, liver and pancreas cancer as compared with the reference population. In patients with liver and pancreas cancer the very high sensitivity contrasted with a low specificity. NAG elevations above normal were observed in 14 (78%) patients with breast cancer, in 11 (100%) with gastric cancer, in 17 (70%) with colorectal cancer, in 8 (100%) with liver cancer and in 9 (100%) with pancreas cancer. In patients with breast and gastric cancer the enzyme shows a good specificity and sufficient sensitivity as a tumor marker. beta-Glucuronidase appeared less sensitive and was significantly elevated (100%) only in patients with pancreas cancer.

Predialysis erythrocyte adenosine deaminase activity was depressed in 12 of 20 patients receiving hemodialysis. In contrast, in 17 patients a marked rise in enzyme activity was observed subsequent to dialysis. Six patients had evidence of neuropathy. Predialysis plasma inhibited normal enzyme activity by an average of 36%, but postdialysis plasma had minimal inhibitory effect. A low molecular weight substance or substances, isolated from the dialysate of uremics, inhibited adenosine deaminase activity by 38%. Three patients having the longest courses of dialysis had no neuropathy and showed no depression of activity, with their plasma failing to inhibit normal activity. It is suggested that accumulation of low molecular weight toxins that depress adenosine deaminase activity may lead to myelin sheath degeneration with subsequent neuropathy. By removing the inhibitor, dialysis may permit nerve repair and eventual recovery.

N-acetyl-beta-glucosaminidase (NAG) and its isoenzymes were measured in 60 patients with breast cancer and in 30 patients suffering from benign breast tumors. NAG activity was significantly increased (P < 0.001) in cancer patients. The concentration of isoenzyme A always exceeded that of isoenzyme B, but isoenzyme B concentration was significantly (p < 0.001) higher in patients than in controls. An intermediate form, I, was more evident but not significant in patients. Evaluation of the predictive value of the NAG isoenzyme B, revealed a good sensitivity, efficiency and specificity. It seems from this study that the determination of the isoenzyme NAG B activity may be useful for better diagnosis of breast cancer.

GlutathioneS-transferase (GST) and carcinoembryonic antigen were measured in the plasma of 95 patients with neoplasm of digestive tract, in 40 patients suffering from non-neoplastic diseases and in 40 healthy subjects. The mean value of the GST activity was significantly (P<0.001) elevated in patients with gastric, liver and colorectal cancer (10.4 U/l, 14.1 U/l and 12.3 U/l respectively) as compared with the reference population (3.2 U/l). GST elevations above normal were observed in 26 (90%) patients with gastric cancer, in 18 (100%) with liver cancer and in 25 (89%) with colorectal cancer. Carcinoembryonic antigen appeared less sensitive. In 15 patients the postoperative levels of serum GST were increased after surgery then gradually declined, and after 1 month showed a normalization in 10 patients. Our data suggest that GST measurement may be useful as a tumour marker in gastric, liver and colorectal cancer. Moreover the combined determination of GST and other markers increase the sensitivity for cancer detection.

Alanine aminopeptidase (AAP), carcinoembryonic antigen (CEA), and tissue polypeptide antigen (TPA) were measured in 40 patients with breast and thyroid cancer and in 40 patients suffering from benign tumors and benign noninflammatory diseases. AAP activity was significantly increased (P < 0.001) in all cancer patients considered together. TPA shows a remarkable diagnostic sensitivity but a low specificity. For CEA an inverse situation is observed. Evaluation of the predictive value of the assay of AAP revealed a sufficient sensitivity, a good specificity, a sufficient predictive value of both positive and negative results, and a good efficiency. We believe that the test, if supported by other information, can be useful in the diagnosis of breast and thyroid cancer.

Serum N-acetyl-beta-D-glucosaminidase has been shown to be a sensitive indicator of liver function. The enzyme activity in serum from patients with different forms of hepatic disease was found to be elevated. A comparison is also made with routine liver parameters. The frequencies of pathological serum levels of the routine measurements made are in relatively good agreement with earlier reports.

The isoenzyme pattern of N-acetyl-beta-glucosaminidase (NAG) in serum and urine was studied in two groups of patients with diabetes mellitus and in 30 control subjects. Total NAG activity was significantly (P less than 0.001) increased in the serum and urine of the 20 diabetics with vascular complications, but was insignificantly increased in the 20 diabetics without vascular complications. Ion-exchange chromatography demonstrated the presence of two major isoenzymes of NAG, A and B. The proportion of isoenzyme A activity always exceeded that of isoenzyme B. The proportion of isoenzyme B in serum of diabetics was lower than in controls; the reverse was true for urine of diabetics. The NAG isoenzymes pattern may provide additional diagnostic information regarding diabetic status and complications of diabetes.

We describe a new high pressure liquid chromatography (HPLC) method for quantitative determination of urinary lysozyme. The method is simple, reproducible and with detection limit of 0.2 microgram. Before HPLC analysis the urine was purified using a Sep-Pak C18 cartridge. Lysozyme concentration was significantly higher in patients with chronic renal failure than in a control group (p less than 0.001). The concentration of lysozyme in urine is shown to be a sensitive indicator of renal damage.

A urinary enzyme pattern consisting of two lysosomal enzymes, N-acetyl-beta-glucosaminidase and lysozyme, and one enzyme originating from kidney tubular brush border membrane, alanine-aminopeptidase, were studied in 30 patients undergoing intravenous urography and arteriography. N-acetyl-beta-glucosaminidase and lysozyme showed the greatest diagnostic sensitivity and were still abnormal on the fifth day after the administration of radio contrast agent. The results, which are statistically significant (Student's t test), suggest that radio-contrast agents are potentially nephotoxic.