Biomedical subjects

Bruno Zappacosta

Publications and source records attributed to Bruno Zappacosta.

7 recordsLinked to original sources

PubMed2006

Analytical evaluation of a new immunonephelometric method for homocysteine measurement.

BACKGROUND AND OBJECTIVES: Increased plasma homocysteine, a sulphur amino acid closely related to methionine metabolism, is considered an independent risk factor for cardiovascular diseases. Over the last years, the request to clinical laboratories for homocysteine measurement is constantly increased and, for this reason, several new methods have been developed, mainly with the aim of using them on completely automated instruments for routine analyses. In this paper, we evaluated a new immunonephelometric method for homocysteine determination on the Dade Behring BNII nephelometer. METHODS: Linearity, recovery, limit of detection (LOD) and total imprecision and were assessed; moreover, the method was compared with a HPLC reference method and with an automated immunoassay method (AxSYM Abbott). RESULTS: Recovery range was 96.4-104.2%, LOD was 0.5 micromol/L and total imprecision ranged from 5.0% to 7.6%. For the comparison study, the immunonephelometric method showed a good correlation both with HPLC (Y=1.02X-0.79, R(2)=0.99) and with the AxSYM method (Y=1.003X+0.06, R(2)=0.98). The Bland-Altman plot analysis shows that the immunonephelometric method has a slight positive bias with both HPLC (mean: 1.03 micromol/L, 95% confidence interval: 0.28-1.79 micromol/L) and AxSYM methods (mean: 0.45 micromol/L, 95% confidence interval: -0.03-0.94 micromol/L). CONCLUSION: The new nephelometric method from Dade Behring, for its analytical performance, can be easily considered a suitable method for homocysteine routine measurement; moreover, it cannot be ruled out that the widespread availability of nephelometers in clinical laboratories play a leading role in the choice of this method.

Adenosylhomocysteinase↗

PubMed2005

Evaluation of a new enzymatic method for homocysteine measurement.

BACKGROUND AND OBJECTIVES: The increased need in clinical chemistry laboratories for methods of homocysteine determination, in correlation with cardiovascular diseases and nutritional deficient status, has led to the development of different analytical methods; fluorescent immunoenzymatic assays and, recently, new fully automated spectrophotometric methods are commercially available. In this paper, we compared data obtained from a new enzymatic method for homocysteine assay (Carolina Liquid Chemistries), with data obtained from a HPLC reference method and an immunoenzymatic method (Abbott AxSYM immunoassay). RESULTS: The enzymatic method shows a good correlation with both the HPLC (Y = -1.3 + 1.02X; R2 = 0.93) and the immunoenzymatic method (Y = 0.7 + 1.02X; R2 = 0.92), although a bias enhancement was present in some samples. However, the enzymatic method shows a superior analytical feasibility because it needs only common laboratory instruments (UV-visible spectrophotometer) and can be easily adapted to large automatic clinical chemistry analyzers. Moreover, it lowers the laboratory cost of the analysis in comparison to both HPLC and immunoenzymatic methods. CONCLUSIONS: The enzymatic Carolina Liquid Chemistries method for homocysteine assay shows acceptable analytical performance and undoubtedly possesses technical and cost advantages.

Adult↗

PubMed2005

Serum levels of folate, homocysteine, and vitamin B12 in head and neck squamous cell carcinoma and in laryngeal leukoplakia.

BACKGROUND: The authors evaluated serum levels of folate, homocysteine, and vitamin B(12) in patients with head and neck squamous cell carcinoma (HNSCC) and in patients with laryngeal leukoplakia, a well known preneoplastic lesion. METHODS: One hundred forty-four consecutive, untreated patients with HNSCC and 40 consecutive, untreated patients with laryngeal leukoplakia were enrolled in the Department of Otolaryngology at the authors' institution. Data from those patients were compared with data from one control group, which included 90 smokers, and from another control group, which included 120 nonsmokers. Serum levels of homocysteine, folate, and vitamin B(12) were measured by an automated immunoassay method based on fluorescence polarization immunoassay technology. RESULTS: Comparing groups by Student-Newman-Keuls test, serum folate levels were significantly lower in patients with HNSCC and in patients with laryngeal leukoplakia compared with serum folate levels in both the smoker control group and the nonsmoker control group. Serum homocysteine levels in patients with HNSCC were significantly higher compared with homocysteine levels both in the smoker and nonsmoker control groups and in patients with laryngeal leukoplakia. There were no statistically significant differences between groups in serum vitamin B(12) levels. CONCLUSIONS: A role for folate deficiency as a risk factor in head and neck carcinogenesis is plausible. A chemoprevention protocol with folate is both feasible and ethically correct and is in progress at the authors' institution. Homocysteine levels in patients with HNSCC probably are affected largely by the HNSCC phenotype. An accumulation of homocysteine may reveal a genetic defect, which, theoretically, may be a target for pharmacologic therapy, for example, with antifolic drugs.

Adult↗

PubMed2005

Hyper-homocysteinemia is not a main feature of juvenile uncomplicated type 1 diabetes.

Total plasma homocysteine (tHcy) was measured by high pressure liquid chromatography (HPLC) method in 28 patients (12 females and 16 males) at the onset of type 1 diabetes mellitus (T1DM), 4 females during diabetes ketoacidosis (DKA) and 154 (68 females and 86 males) during follow-up. Serum folate, pyridoxal 5' phosphate (PLP) and Vitamin B12 (Vit B12) were also measured. Plasma tHcy levels were not found significantly different in T1DM patients known to have diabetes (males 9.2 +/- 7.7 and females 7.0 +/- 2.8 micromol/l) and in those who were newly diagnosed (males 9.7 +/- 4.8 and females 7.16 +/- 2.8 micromol/l) than in healthy controls (males 8.7 +/- 3.5 and females 7.8 +/- 2.55 micromol/l). Only a significant difference for sex was observed in known diabetes (p = 0.0281). Serum folate, PLP and Vit B12 were normal (12.6 +/- 3.6 ng/ml, 20.11 +/- 0.8 ng/ml and 416.7 +/- 41.9 pg/ml) in all T1DM patients. Age significantly correlated with plasma tHcy. Only in 4 patients, studied during DKA, plasma tHcy was significantly lower (2.76 +/- 1.33 micromol/l, p < 0.001) than the healthy controls.

Adolescent↗

PubMed2003

HPLC analysis of some sulphur compounds in saliva: comparison between healthy subjects and periodontopathic patients.

BACKGROUND: Saliva is an easily available biological material that is not commonly analysed in clinical chemistry, while it could give useful information especially in several oral diseases. METHODS: In this work, the sulphur containing compounds cysteine, cysteinylglycine and glutathione were analysed in saliva of control subjects and periodontopathic subjects by a HPLC method. The detection limit of the method is 0.5, 0.1 and 0.1 micromol/l for cysteine, cysteinylglycine and glutathione, respectively, and it is linear up to 10 mmol/l. RESULTS: the median values for the control group are 1.2 micromol/l for cysteine and glutathione and 0.4 micromol/l for cysteinylglycine while those of periodontopathic patients are significantly increased (4.4, 2.1 and 11.0 micromol/l for cysteine, cysteinylglycine and glutathione, respectively).

Adult↗

PubMed2002

Serum folate and homocysteine levels in head and neck squamous cell carcinoma.

BACKGROUND: Local and systemic metabolic alterations are always present in cancer. Carcinogenesis is associated with biochemical disorders, often nonspecific, that might promote or derive from tumoral progression. Thus, analysis of metabolic alterations may be a valuable approach to understanding the biochemistry of tumors and may provide a means of identifying new targets for therapy. The methionine cycle in particular has been extensively studied in human cancer. METHODS: The authors analyzed serum concentrations of two metabolites of such pathways, folate and homocysteine, in 42 patients affected by head and neck squamous cell carcinoma (HNSCC) in comparison with two control groups, composed of smokers and non smokers. RESULTS: Mean folate level was 5.8 +/- 2.1 ng/mL in carcinoma patients, 9.1 +/- 2.7 ng/mL in smoking controls, and 9.7 +/- 2.2 ng/mL in non smoking controls, with a statistically significant difference between carcinoma patients and smokers (mean difference: -3.3 ng/mL; 95% confidence interval [CI]: -4.234 to -2.366; P < 0.0001) and between carcinoma patients and non smokers (mean difference: -3.9 ng/mL; 95% CI: -4.67 to -3.13; P < 0.0001). Mean total homocysteine level was 10.4 +/- 5.3 microM in carcinoma patients, 7.8 +/- 2.5 microM in the non-smokers' group, and 8.3 +/- 2.8 microM in the smokers' group, with statistically significant differences between carcinoma patients and smoking controls (mean difference: 2.1 microM; 95% CI: 0.7056 to 3.494; P = 0.0034) and between carcinoma patients and non smoking controls (mean difference: 2.6 microM; 95% CI: 1.381 to 3.819; P < 0.0001). CONCLUSIONS: Differences in serum levels of folate and homocysteine might arise from tumor development and consequent metabolic alterations or might precede and promote tumor progression. If hypofolatemia is a risk factor for head and neck carcinogenesis, it might suggest a role for folate as a novel chemopreventive agent both in patients with precancerous lesions and in patients with treated HNSCC at risk for loco-regional recurrence and second primary tumors.

Adult↗

PubMed2002

Comparing different methods for homocysteine determination.

Slightly elevated values of homocysteine are commonly associated with thromboembolic diseases, while high values can be found in patients with congenital metabolic defects or nutritional problems. The clinical use of homocysteine as an independent marker of cardiovascular disease was limited in the past by technical problems with its measurement, the instrumentation (HPLC, radioenzymatic assays, gas chromatography-mass spectrometry, etc.) and the necessary skills required. Commercially available immunoassays now permit a simpler and more rapid measurement of homocysteine, that is more suitable for routine clinical laboratories; in this paper we analyze the results obtained by using three fully automated methods for homocysteine determination (Abbott IMx immunoassay, Abbott AxSYM immunoassay and Immulite 2000 homocysteine immunoassay) and their correlation with the widely used HPLC method. The results clearly indicate that all three automated immunochemical methods correlate well with the HPLC method (slope 0.97-1.03; intercept 0.95-1.91 with a recovery above 95% for all three methods).

Adolescent↗