High-performance liquid chromatographic determination of total plasma homocysteine with or without internal standards.

Hyperhomocysteinemia is an independent risk factor for atherosclerosis and vascular occlusive disease. Assessment of total plasma concentration of homocysteine (tHcys) requires accurate and reproducible measurements. The aim of this study was to test a rapid isocratic HPLC method for tHcys analysis with an internal standard (I.S.) of alpha-mercaptopropionylglycine (MPG), 2-mercaptoethylamine (ME), or N-acetylcysteine (NAC) or without I.S., and to verify whether the use of an I.S. improves the precision. The method without I.S. showed an excellent linearity (y = 1.59x - 0.15, r = 1), recovery (100%) and a within-assay relative standard deviation (R.S.D.) of 1.2%. Instead, in our hands, the presence of I.S.s decreased the reproducibility (within-assay R.S.D. ranged from 4.5 to 6.5%) and lengthened the chromatogram by up to four to five times. In conclusion, HPLC measurement of plasma tHcys without I.S. improves accuracy with respect to determination with I.S.; moreover, this approach allows to routinely process larger amounts of plasma samples.

Screening of homocysteine from newborn blood spots by high-performance liquid chromatography with coulometric array detection.

Homocystinuria, due to a deficiency of cystationine-beta-synthase, refers to the rare inborn error of the metabolism of homocysteine. The identification and prompt treatment of homocystinuria during the neonatal period can prevent or greatly reduce the severity of the clinical consequences. We report a new method for homocystinuria diagnosis from dried blood spots on newborn screening cards, based on high-performance liquid chromatography with electrochemical coulometric array detection. This method shows an excellent linearity (y=10.36x+0.04; r=0.999), precision (RSDs ranged from 2.7 to 5.8%), recovery (87%) and appears to be a cost-effective approach, being simple, rapid, sensitive and cheap.

Serum levels of procollagen type I carboxyterminal extension peptide in cancer patients with bone metastases.

Serum levels of procollagen type I carboxy-terminal extension peptide (PICP) reflect the synthesis of type I collagen. As PICP is produced by osteoblasts and is not incorporated into bone matrix, serum PICP levels have been suggested as a marker of bone formation. In 37 cancer patients (21 men and 16 women; age: 72.4 +/- 8.6 (mean +/- SD) years) with bone metastases and 23 women (age: 77.3 +/- 6.64 years) as controls, the following biochemical variables were measured: serum PICP, calcium (Ca), phosphorus, alkaline phosphatase (AP) and tartrate-resistant acid phosphatase (TRAP), and urinary hydroxyproline and calcium corrected for creatinine excretion. Higher serum levels of PICP were observed in cancer patients than in control (245 +/- 177 micrograms/l vs 121.7 +/- 36 micrograms/l, p < 0.01). Cancer patients also had higher AP levels than controls (704 +/- 755 U/l vs 216.5 +/- 56 U/l, p < 0.01). Abnormal PICP and AP serum concentrations (above the mean + 2SD of controls) were found in 46% and 51% of patients, respectively. Moreover, patients showed significantly lower serum calcium concentrations (p < 0.001), and higher TRAP and hydroxyproline levels although statistical significance was not reached. In the patients, PICP was correlated directly with AP (r = 0.50, p < 0.01) and TRAP (r = 0.34, p < 0.05). In conclusion, patients with bone metastases have increased bone turnover as shown by serum markers. Serum PICP may be used as an adjunctive, non-invasive index to assess bone metabolism. However, the clinical usefulness of PICP in cancer patients needs further evaluations.

8 determination of plasma homocysteine.

INTRODUCTION: A number of epidemiological and clinical studies have linked elevated plasma homocysteine (Hcy) to atherosclerotic vascular disease affecting coronary, carotid, and peripheral vessels. Plasma Hcy can be considered a marker of methionine metabolic efficiency, mainly affected by dietary intake of vitamins, especially folate, vitamin B(6), and B(12), as well as by genetic mutations of key metabolic enzymes and renal elimination.

A study of plasma CEA by a direct radioimmunoassay method in 1704 cases.

The authors have used an original method of direct radioimmunoassay of plasma CEA for testing plasma of 1704 patients affetected by various neoplastic and non-neoplastic diseases. The percentage of positive results in blood from patients with adenocarcinoma of the gastroenteric tract was 66.8%. The positivity in other non-neoplastic diseases was 2.7%, except for liver cirrhosis and other chronic hepatopathies, which showed 29.6% of positive reactions. The test should be clinically useful in the differential diagnosis of gastro-enteric carcinoma.

A new HPLC micromethod to measure total plasma homocysteine in newborn.

Total plasma homocysteine (tHcy) in children may be an useful biochemical marker for genetic risk of premature cardiovascular disease. We reported a rapid, isocratic HPLC method able to process very small amount of newborn plasma samples. A blood sample from heel capillary circulation was collected, using a heparinized capillary glass tube. Plasma sample from 1 to 10 microl was derivatized with ammonium-7-fluorobenzo-2-oxa-1,3-diazole-4-sulphonate after reduction with tri-n-butylphosphine and analyzed on Discovery C18 column, with a solution of acetonitrile-dihydrogenphosphate 0.1 M (8:92 v/v pH*2.1). This assay ensures a good recovery (95%), precision (CV 4.5%) and linearity (y=2.41x + 0.31, r=1). Due to its simplicity and reliability, our method is suitable for routine analysis of tHcy and other aminothiols (Cys, Cys-Gly, GSH) assessed for clinical and research purposes. With this HPLC method we have assayed tHcy levels in 1400 apparently healthy newborn babies (tHcy mean value=4.9+/-2.7 microM). In conclusion, this accurate and linear HPLC method allows measurement of tHcy in newborn during the routinary capillary blood collection in the fourth living day without any other invasive procedure.

Homocysteine, vitamin B12, and serum and erythrocyte folate in peritoneal dialysis and hemodialysis patients.

BACKGROUND: Plasma homocysteine (Hcy) is an independent risk factor for cardiovascular disease. High levels of plasma Hcy have been observed in end-stage renal disease patients. Few studies have compared peritoneal dialysis (PD) and hemodialysis (HD) patients and few data are available on erythrocyte folate (ery-F) levels in dialysis patients. OBJECTIVES: To evaluate plasma Hcy concentrations, vitamin B12 (B12), and folate status in dialysis patients; to analyze the possible causes of high Hcy levels; to follow up changes in folate and B12 concentrations after 6 months. DESIGN: A cross-sectional observational study. SETTING: Nephrology division and laboratory of hematology in a university and clinical research hospital. PATIENTS: The study included 82 patients treated with PD for 37 + 37 months and 70 patients treated with HD for 136 + 95 months. LABORATORY METHODS: Plasma Hcy was measured by the immunoenzymatic IMx Hcy FPIA method (Abbott Laboratories, Diagnostic Division, Abbott Park, IL, U.S.A.), serum folate (s-F) and ery-F by the Stratus folate fluorometric enzyme-linked assay, and B12 by the Stratus vitamin B12 fluorometric enzyme-linked assay (DADE-Behring, Newark, DE, U.S.A.). RESULTS: Ninety-six percent of PD and 97% of HD patients had Hcy levels above the cutoff (13.5 micromol/L). Homocysteine level was higher in HD than in PD patients, while the prevalence of hyperhomocysteinemia was similar with the two techniques. Erythrocyte folate was significantly higher in PD (1333 +/- 519 pmol/L) than in HD (1049 +/-511 pmol/L, p < 0.01). Statistically significant correlations were observed between Hcy and B12, s-F, ery-F, and dialysis duration. Multivariate analysis showed a strong correlation between s-F and Hcy. After 6 months there were no differences in Hcy, B12, s-F, and ery-F levels. CONCLUSIONS: Plasma Hcy levels were high in more than 95% of our dialysis patients, with no relation to the type of dialysis. Vitamin B12 and folate were normal in the majority of our patients. However, serum folate was the major determinant of Hcy levels. Such a relation between Hcy and folate suggests that levels of folate within the reference interval are inadequate for dialysis patients.

[Direct radioimmunological determination of plasma CEA in 1704 patients]. / Dosaggio radioimmunologico diretto del CEA plasmatico in 1704 pazienti.

An original technique for the direct radioimmunological measurement of plasma CEA has been prepared. Compared to the other in use, this has the advantage of a very low incidence of false positivity. 1704 patients make up the series: the percentage of positivity in 247 suffering from gastroenteric adenocarcinoma was 66.8%, in 60 with lung cancer 30%, in 243 with malignant tumours in various sites 7.4%, in 199 with chronic liver diseases 29.6% while in 598 cases of other non-neoplastic diseases it was only 2.5%. 212 patients who underwent radical surgery for gastroenteric adenocarcinoma were also followed up and the test provided early diagnosis of the clinical re-onset of the neoplastic lesion. It is considered that plasma CEA measurement represents a useful aid to the clinician althouth it cannot be employed at present to screen gastroenteric adenocarcinomas.

Effects of combined dietary supplementation on oxidative and inflammatory status in dyslipidemic subjects.

BACKGROUND AND AIM: Dyslipidemia is one of the main risk factors for atherosclerosis, usually the underlying cause of cardiovascular diseases which are the major cause of morbidity and mortality in developed countries. The aim of this study was to assess the effects and the advantages of a combined dietary supplementation with PUFA n-3, vitamin E, niacin and gamma-oryzanol on lipid profile, inflammatory status and oxidative balance. METHODS AND RESULTS: Fifty-seven dyslipidemic volunteers were randomly assigned to receive: placebo (group A, 19 subjects); PUFA n-3 and vitamin E (group B, 18 subjects); the same as B plus gamma-oryzanol and niacin (group C, 20 subjects). Lipid profile, reactive oxygen species (ROS), total antioxidant capacity (TAC), vitamin E, interleukin 1-beta (IL1-beta), tumor necrosis factor (TNF-alpha) and thromboxane B2 (TXB2) were determined at baseline (T0) and after four months (T1). All dyslipidemic subjects showed, at baseline, oxidative stress and, after four months, all biochemical markers improved significantly in groups treated with dietary supplementation. Particularly in group C all lipid patterns improved significantly. CONCLUSIONS: Our findings demonstrate that the strategy of combining different compounds, which protect each other and act together at different levels of the lipid chain production, improves lipid profile, inflammatory and oxidative status, allowing us to reduce the dose of each compound under the threshold of its side effects.

Preliminary studies of nonvirion antigens associated with herpes simplex virus 1 and 2 (HSV1 - HSV2).

Biochemical and radioimmunological studies have indicated the presence of a nonvirion antigen associated with herpes virus. Guinea pig kidney cells were grown in culture and infected (I-cells) for 3h with herpes virus. Uninfected cells (N-cells) served as control. The cells were collected and sonicated to obtain, after centrifugation, "soluble extract" (SI, SN). The pellets were extracted with KCl (ISP, NSP). SN, SI were submitted to gel-filtration on Sephadex G-200. Extracts from I and N cells gave similar patterns. After labelling with 125I, greater resolution was obtained in a second gel-filtration with a much smaller load. ISP contained protein species not present in NSP. Polyacrylamide gel electrophoresis of peaks from SN and SI showed that SI contained some radioactive bands not found in SN. Labelled materials from SI and SN were incubated with sera from cancer patients and normal subjects. No differences in binding were seen with SN, but SI showed 14-30% more 125I binding with sera of cancer patients than with sera from normal subjects. No such difference was seen between ISP and NSP.

BCA (breast cancer antigens): different purification extraction methods.

Various types of extraction were tested to increase the immunological yield of BCA, a CEA-like primary breast cancer associated carcinoma antigen. To allow a comparison, the different extraction techniques were applied to only one breast tumour. The comparison of the various systems was based on two parameters: protein yield and immunological activity, assayed in a RIA 125I CEA-anti CEA system. The following extraction methods were described and compared in this paper: 3M KCl; 1N HClO4; neutral pH extraction (PBS) in the absence and presence of various detergents (anionic, neutral and cationic), basic pH extraction (1N NaOH) and acid pH extraction (1.5M acetic acid) in the presence of urea and various detergents. The more significant systems were applied also to the extraction of CEA, from colonic adenocarcinoma liver metastases. The best results for both the antigens studied were obtained by using neutral detergents (1% NP 40) at neutral pH.

Extraction and partial purification of a CEA-like BCA from a pool of pre-selected breast carcinomas.

By exploiting the cross-reaction among the antigens associated with a pool of breast carcinomas, preselected according to their antigenic content, a CEA-like BCA, with a specific activity of 1400 U/micrograms has been extracted, by means of 3M KCl, and partially purified by means of ConA Sepharose affinity chromatography and bioabsorption, employing, for the latter, a cross-reacting antiserum (anti CEA). The subsequent labelling, after Sephadex G-200 gel filtration, points out an immunological activity at the apex of the first peak versus anti CBC (or C.BCA) and anti CEA.

CEA and immunosuppression: investigation performed on patients with gastrointestinal advanced adenocarcinomas treated with immunochemotherapy.

No statistically significant correlations were detected between plasma CEA levels, DNCB skin test responses, peripheral lymphocytes and plasma immunoglobulins in 90 patients with G.I. advanced adenocarcinomas, treated with BCG aspecific immunotherapy and chemoterapy.

Identification of alpha 1-adrenergic receptors on sarcolemma from normal subjects and patients with idiopathic dilated cardiomyopathy: characteristics and linkage to GTP-binding protein.

Discontinuous density sucrose gradient centrifugation was used to isolate membrane vesicles from the left ventricle of three normal subjects (one prospective organ donor and two traffic victims whose hearts were obtained 1 hour after death) and nine patients undergoing cardiac transplantation as a consequence of idiopathic dilated cardiomyopathy. Sarcolemma-enriched subcellular fractions, detected in the interface between 8.55% and 25% sucrose, were identified by the increased activity of Na+,K+-ATPase and by enrichment in beta-adrenergic receptor density. The density of beta-adrenergic receptors was lower in vesicles from diseased hearts (610 +/- 71 fmol/mg protein) than in vesicles from normal hearts (1,410 +/- 226 fmol/mg protein; p less than 0.01). alpha 1-Adrenergic receptors were identified in these membrane vesicles by [3H]prazosin binding. Specific binding of [3H]prazosin was about 50% of the total binding at 1 nM, and alpha 1-adrenergic binding sites were saturable at approximately 3 nM. Scatchard analysis revealed 58 +/- 5 fmol/mg protein (KD = 0.90 +/- 0.08 nM) in pathological hearts and 30 +/- 5 fmol/mg protein (KD = 0.90 +/- 0.03 nM) in normal hearts (p less than 0.01). The displacement curve of (-)-norepinephrine in membrane vesicles from normal hearts delineated one subpopulation of alpha 1-adrenergic receptors; the addition of 0.1 mM GTP did not cause right shift. In membrane vesicles from diseased heart, the displacement curve of (-)-norepinephrine disclosed two subpopulations of alpha 1-adrenergic receptors. A right shift that occurred after addition of GTP showed that in this case alpha 1-adrenergic receptors were functionally coupled with GTP-binding protein.(ABSTRACT TRUNCATED AT 250 WORDS)

An examination of heart proteins by two-dimensional electrophoresis.

We examined specimens from explanted human hearts by two-dimensional electrophoresis. The protocol selected includes: (a) solubilization of the sample in a urea-detergent mix; (b) charge fractionation in the presence of urea and nonionic detergent on a pH 4-10 immobilized pH gradient; (c) size fractionation on a polyacrylamide concentration gradient in the presence of sodium dodecyl sulfate; and (d) staining with silver nitrate. The method is sensitive enough for analysis of biopsies in the 1-3 mg range (wet tissue). We saw, for explanted hearts, variations in the protein pattern with the site of sample dissection. Results are presented for 11 explanted human hearts: one control organ and 10 pathological samples. The recorded pathologies included dilatative cardiomyopathy (six cases), valvulopathy (one case), ischemic cardiopathy (two cases), and graft rejection (one case). The patterns for whole extracts as well as for cytoplasmic proteins and myofibril components are compared. Extensive individual variability was observed both between control and pathological cases and among the abnormal samples.

Myocardial blood flow distribution in patients with ischemic heart disease or dilated cardiomyopathy undergoing heart transplantation.

BACKGROUND: The present investigation was designed to obtain an absolute measurement of myocardial blood flow and of its transmural distribution in ischemic heart disease and idiopathic dilated cardiomyopathy and to provide a reference standard for cardiac imaging in nuclear cardiology. METHODS AND RESULTS: Regional myocardial blood flow and its transmural distribution were estimated by the reference microsphere method in eight patients with idiopathic dilated cardiomyopathy (n = 4) or ischemic heart disease (n = 4) during heart transplant procedure. Before aortic clamping, 99mTc-labeled human albumin microspheres were injected into the left atrium while arterial blood was sampled from the aorta at a constant rate. No complications were observed during or after the procedure. From the excised heart, myocardial slices for gamma camera imaging and well counting analysis were obtained. Myocardial blood flow was assessed by a well counter, correlated with the extent of fibrosis expressed as collagen per total tissue proteins obtained from 4-hydroxyproline and glycine as determined by high-performance liquid chromatography. Microsphere distribution, as seen by gamma camera images in a different slice, was correlated with the extent of fibrosis assessed by histological analysis of the same myocardial specimen. Mean transmural myocardial blood flow was 0.49 +/- 0.17 and 0.38 +/- 0.15 mL.min-1 x g-1 in idiopathic dilated cardiomyopathy and ischemic heart disease, respectively (P < .01). Endocardial-to-epicardial flow ratio was lower in ischemic heart disease than in idiopathic dilated cardiomyopathy patients (0.99 +/- 0.33 versus 1.16 +/- 0.30, P < .05). Mean myocardial fibrosis was 9 +/- 6% in idiopathic dilated cardiomyopathy and 25 +/- 28% in ischemic heart disease. In both groups, no correlation was found between myocardial blood flow values and the extent of fibrosis. In ischemic heart disease, regional myocardial blood flow was not significantly affected by the severity of coronary stenosis (< or = 70% or > 70%) either in the endocardium (0.44 +/- 0.24 versus 0.36 +/- 0.16 mL.min-1 x g-1, P = NS) or in the epicardium (0.50 +/- 0.33 versus 0.38 +/- 0.33 mL.min-1 x g-1, P = NS). By gamma camera imaging, transmural microsphere distribution appeared more homogeneous in idiopathic dilated cardiomyopathy than in ischemic heart disease (mean coefficient variation, 18% and 27%, respectively; P < .02); the severity of perfusion impairment did not correlate with the extent of fibrosis evaluated by histological criteria. CONCLUSIONS: Heart transplant surgery offers a valuable model to assess absolute myocardial perfusion in human heart failure. Myocardial blood flow is markedly depressed in failing hearts of both ischemic heart disease and idiopathic dilated cardiomyopathy patients; a different transmural myocardial blood flow distribution is observed in ischemic heart disease than in idiopathic dilated cardiomyopathy, with prevalent endocardial perfusion in the latter but not the former condition. In patients with end-stage heart failure, myocardial blood flow appears to be similarly impaired in fibrotic and viable regions. Mechanisms other than myocardial fibrosis and coronary lesions appear to operate in determining myocardial blood flow impairment in heart failure.