Diagnostic performance of the urinary bladder carcinoma antigen ELISA test and multiparametric DNA/cytokeratin flow cytometry in urine voided samples from patients with bladder carcinoma.

BACKGROUND: The objective of the current study was to comparatively analyze the sensitivity and specificity of flow cytometric DNA/cytokeratin 8/18 measurements and the urinary bladder carcinoma antigen (UBC) enzyme linked immunoabsorbent assay (ELISA) test for the detection of bladder carcinoma in voided urine samples. METHODS: Eighty-one fresh urine voided samples, preserved frozen for a maximum period of 3 months, belonging to patients with an active bladder carcinoma (n = 37), patients who were free of disease as confirmed by cystoscopy (n = 19), patients receiving intravesical therapy (n = 17), and individuals with other benign and malignant conditions (n = 8), were collected. Flow cytometry measurements of thawed samples were based on the detection of cytokeratin (CK) 8+ and CK18+ cells using the 3F3 and 6D7 monoclonal antibodies alone or in combination with the measurement of cell DNA contents, after propidium iodide staining. Urinary bladder carcinoma antigen test was measured by ELISA. RESULTS: Patients were grouped according to the presence (n = 44) or absence (n = 29) of bladder carcinoma as confirmed by cystoscopy, and taking cutoffs of 9.7 microg/L for UBC-ELISA, 75% for the percentage of 3F3 (+) and 6D7 (+) cells, and 10.6% for the proportion of hyperdiplod cells that suggested a specificity of 83%, the individual sensitivity obtained for each parameter was 77%, 5%, 9%, and 77%, respectively. The presence of DNA aneuploid populations showed a relatively low sensitivity (36%) although it was the most specific parameter (93%). Combining UBC antigen test with the proportion of cells showing DNA content higher than 2n increased to 89% the sensitivity of the UBC antigen alone. However, false-positive results for both techniques were found in individuals with urologic diseases other than bladder carcinoma and in patients receiving intravesical therapy. CONCLUSIONS: The authors' results suggest that the combined use of the UBC antigen test and DNA/cytokeratin flow cytometry double stainings for the analysis of freshly obtained urine voided samples, cryopreserved to assure cellular integrity, is of great clinical utility for the detection of tumor recurrence in patients with bladder carcinoma.

Utility of serial urinary tumor markers to individualize intervals between cystoscopies in the monitoring of patients with bladder carcinoma.

BACKGROUND: Cross-section studies have shown the diagnostic characteristics of certain urinary tumor markers for the detection of bladder carcinoma. However, the role of serial urinary tumor markers in the monitoring of patients with bladder carcinoma in daily clinical surveillance has not been completely defined yet. METHODS: The study comprised 1185 urine samples belonging to 232 patients with a previous bladder carcinoma: 106 patients under follow-up (Group 1) and 126 bladder carcinoma patients receiving intravesic instillations (Group 2). Patients were monitored with urinary tumor markers during a one-year follow-up period. Urine samples were collected before cystoscopies and in the intercystoscopic periods for patients in Group 1 and before intravesic instillations for patients Group 2. Urinary bladder carcinoma antigen (UBC), CYFRA 21-1 and nuclear matrix proteins (NMP22) were measured by immunoassays. RESULTS: Monitoring of the disease with urinary tumor markers could detect recurrence sooner than scheduled cystoscopies in 27 patients (87%) for UBC, 27 patients (87%) for CYFRA 21-1, and 26 patients (84%) for NMP22 out of 31 Group 1 patients who recurred; and in 16 patients (67%) for UBC, 17 patients (71%) for cytokeratin fragments (CYFRA) 21-1, and 13 patients (54%) for NMP22 out of 24 Group 2 patients who recurred. The most relevant finding was that persistence of negative urinary markers during follow-up was largely indicative of disease free status in 65 of 75 (87%) patients of Group 1 and 31 of 102 (30%) cases of Group 2. Although false positive results were present, they were mainly associated with sporadic urinary tract infections in 10 of 75 (13%) cases of Group 1 and in 36 of 102 (35%) patients of Group 2; and with urine samples collected in the first two months at the beginning of intravesic therapy in 35 of 102 patients (34%) in Group 2. CONCLUSIONS: Monitoring of bladder carcinoma patients with serial urinary tumor markers could anticipate detection of recurrence. Persistent negative results might postpone and reduce the number of cystoscopies. Once the limitations leading to false positive results are controlled by urinalysis and by starting sample collection when basal levels are reached in patients with intravesic therapy, urinary tumor markers might eventually individualize the intervals between cystoscopies in the surveillance of patients with bladder carcinoma.

Serial urinary IL-2, IL-6, IL-8, TNFalpha, UBC, CYFRA 21-1 and NMP22 during follow-up of patients with bladder cancer receiving intravesical BCG.

BACKGROUND: We evaluated the potential role of serial preinstillation levels of several interleukins, TNFalpha and urinary tumor markers to monitor patients with bladder cancer receiving intravesical BCG. PATIENTS AND METHODS: 121 urine samples were collected from: patients with bladder cancer treated with BCG (group 1); patients with bladder cancer receiving other intravesical treatment (group 2) and patients with urinary tract infections (group 3). Cytokines [IL-2, IL6 and [L8] and TNFalpha and urinary tumor markers [UBC, CYFRA 21-1 and NMP22] were measured by immunoassays. RESULTS: In 3 out of 15 BCG non-responders that recurred over the period of the study, no cytokine peak for IL-2, IL-6 or TNFa were detected. Urinary tumor markers increased in 2 out of 3 of these patients earlier than scheduled cystoscopies. Cytokine measurement was heterogeneous among 12 out of 15 BCG-responding patients: there were low levels of IL-6 and TNFalpha and peaks of IL-2 and IL-8 in 10 out of 12 and 4 out of 12 patients, respectively. During responding patients' follow-up we observed false-positive results in 7 out of 65 urine samples for UBC, 8 out of 65 for CYFRA 21-1 and 20 out of 65 for NMP22. Urinary tract infections were the main factor associated with non-specific elevations of IL-6 and IL-8 and urinary tumor markers in all groups of patients. CONCLUSION: Although larger series are required to confirn our preliminary observations, our data argue for a potential predictive role for IL-2 of favourable response to BCG therapy. Monitoring BCG with urinary tumor markers could early detect recurrence in non-responding patients.

Biological variation of interleukin-1beta, interleukin-8 and tumor necrosis factor-alpha in serum of healthy individuals.

Components of biological variation can be used to assess the usefulness of reference values, to evaluate the significance of changes in serial results from an individual and to define objective analytical goals. The aim of the study was to assess, in 15 healthy subjects studied at regular monthly intervals over a period of 6 consecutive months, the biological variation of interleukin-1beta (IL-1beta), interleukin-8 (IL-8), and tumor necrosis factor-alpha (TNF-alpha). Biological variation data (within-subject and between-subject coefficient of variation (CV)) were determined using a simple nested analysis of variance. Derived parameters (index of individuality, reliability coefficient and critical diferences) were calculated from within-subject and between-subject CV. The mean and standard deviation (SD), within-subject CV, between-subject CV, index of individuality and reliability coefficient were as follows: for IL-1beta, 0.67 (0.32) pg/ml, 30%, 36%, 0.85, and 0.76; for IL-8, 3.68 (1.45) pg/ml, 24%, 31%, 0.85 and 0.75; and for TNF-alpha, 3.14 (1.87) pg/ml, 43%, 29%, 1.56 and 0.50, respectively. We conclude that between-subject variation and within-subject variation are quite similar for IL-1beta and IL-8 and are relatively high for the three cytokines studied. Index of individuality is less than 1.4 for IL-1beta and IL-8, and thus reference intervals based on population studies are of limited value. On the contrary, the index of individuality for TNF-alpha is greater than 1.4 and reference values can be used for diagnosis. Quality goals for imprecision are easily achieved for the three cytokines with current methodology.

Comparative predictive values of urinary cytology, urinary bladder cancer antigen, CYFRA 21-1 and NMP22 for evaluating symptomatic patients at risk for bladder cancer.

PURPOSE: We study the potential diagnostic use of urinary bladder cancer antigen, CYFRA 21-1 and NMP22*; for evaluating symptomatic patients who present with microscopic hematuria and are at risk for bladder cancer. MATERIALS AND METHODS: Urinary tumor markers were determined in 187 samples from 112 patients symptomatic of bladder cancer (group 1), and 75 with benign and other urological conditions (group 2). Immunoassays were used to measure the 3 selected biomarkers. Sensitivity and specificity were established by previously defined cut points. Biomarker results were reported as corrected and uncorrected for urinary creatinine. Urinalysis was performed in all samples. RESULTS: Positive and negative predictive values were 85.5%, 80.5% and 81.1%, and 80.8%, 79.2% and 76.5% for urinary bladder cancer antigen, CYFRA 21-1 and NMP22, with the cutoffs 9.7 microg./l., 5.4 microg./l and 10.0 units per ml., respectively. These predictives values were 85.2% and 72.5%, respectively, for urinary cytology. The combination of biomarkers decreased the positive predictive values to 72.3% to 78.6% and increased negative predictive values to 84.2% to 86.1%. Urinary tract infection, inflammation and malignancy associated with other genitourinary organs were the primary cause for false-positive test results in the 3 assays evaluated. CONCLUSIONS: With a single biomarker, around 80% of the positive results would have correctly identified symptomatic patients for cystoscopy. Of the negative results 75% would have correctly reduced the number of cystoscopies. Sensitivity and negative predictive values could be improved with the combination of biomarkers but with a loss of specificity and positive predictive values. Urinary tract inflammation and other genitourinary malignancies might contribute to the reduction in specificity of these tests.

Evaluation of two new urinary tumor markers: bladder tumor fibronectin and cytokeratin 18 for the diagnosis of bladder cancer.

Our objectives were to evaluate the diagnostic value of two new urinary tumor markers, cytokeratin 18 (CK18) and bladder tumor fibronectin (BTF), for the detection and monitoring of bladder cancer. The study comprised 931 urine samples belonging to 402 subjects: 112 individuals under suspicion for a primary bladder tumor (group 1); 104 bladder cancer patients under scheduled follow-up (group 2); 109 bladder cancer patients receiving intravesical instillations (group 3); 45 patients with other urological diseases (group 4); and 32 healthy subjects (group 5). Voided urine samples were collected before cystoscopies, between them and before intravesical instillations. CK18 and BTF tests were measured by chemiluminescent immunoassays. Optimal receiver operating characteristic cutoffs of 7.4 microg/L for CK18 and 52.8 microg/liter for BTF rendered overall sensitivities of 66.2% for CK18 and 80.0% for BTF at specificities of 88.4 and 74.7%, respectively. Urinary cytology provided a sensitivity of 29.2% at a specificity of 99.1%. Sensitivities were 80.8, 74.2, and 82.3% for BTF and 71.1, 77.4, and 64.7% for CK18 for groups 1 to 3, respectively. False positive rates were higher for BTF in all groups of patients. Elevated urinary tumor markers during the monitoring of patients with bladder cancer could detect recurrence sooner than scheduled cystoscopies. Persistence of negative markers was greatly indicative of free of disease status in follow-up. CK18 and BTF in urine may eventually prove to be of benefit for specific patients with bladder carcinoma given its higher sensitivity compared with cytology. In selected patients, namely those with persistent negative urinary CK18 and BTF, the number of cystoscopies could be reduced.

Biological variation of interleukin 6 (IL-6) and soluble interleukin 2 receptor (sIL2R) in serum of healthy individuals.

The biological variation of interleukin 6 (IL-6) and soluble interleukin 2 receptor (sIL2R), measured by automated enzyme immunoassay, in fifteen subjects studied at regular monthly intervals over a period of 6 consecutive months was measured. The mean and standard deviation (SD), within-subject CV, between-subject CV, individuality index (II) and reliability coefficient (R) were as follow: for sIL2R 571 (231) U/ml, 5.84%, 38.81%, 0.21 and 0.93; and for IL-6 1.43 (0.9) pg/ml, 48.48%, 39.38%, 1.44, and 0.37. The data indicate a relatively high between-subject CV, quite similar in both cases, and a within-subject CV much higher for IL-6 than for sIL2R. Thus, reference values can be used for diagnosis for IL6 (high II), while not for sIL2R (low II). However, the low R for IL-6 implies that more than one measurement are needed. sIL2R has a very high R and a relatively small critical differences, a circumstance appropriate for follow-up.

[Cytokeratins (UBC and CYFRA 21-1) and nuclear matrix proteins (NMP22) as urine tumor markers in the diagnosis of bladder cancer]. / Citoqueratinas (UBC y CYFRA 21-1) y proteínas de la matriz nuclear (NMP22) como marcadores tumorales en la orina en el diagnóstico del cáncer vesical.

BACKGROUND: The development of urinary tumor markers such as UBC, CYFRA 21-1 and NMP22 appeared to be non invasive alternative methods for the detection of bladder cancer. We compared the individual and combined sensitivity of the urinary tumor markers in the detection of bladder cancer, contrasting them with the conventional diagnostic procedures. PATIENTS AND METHODS: 237 voided urines from subjects under risk for bladder cancer were collected immediately before the endoscopic examinations: 44 patients under suspicion of a primary bladder tumor and 193 patients under follow-up of a previous bladder cancer were included. UBC and NMP22 were measured by enzyme-immunoabsorbent-assays and CYFRA 21-1 by an electro-chemiluminescense-immunoassay. RESULTS: Taking the cutoffs of 9.7 micrograms/l for UBC, 5.4 ng/ml for CYFRA 21-1 and 10.0 U/ml for NMP22 sensitivities were 70%, 69% and 67% for UBC, CYFRA 21-1 and NMP22 at specificities of 95%, 94% y 80%, respectively. All tumor markers showed higher sensitivities than urinary cytology (7%), microhematuria (62%) and gross hematuria (10%) at specificities of 99%, 78% and 99%, respectively. The combinations of NMP22 plus CYFRA 21-1 reached the highest sensitivity (79%), slightly lower than simultaneously measuring the three tumor markers (80%). CONCLUSIONS: The sensitivities of the urinary markers UBC, CYFRA 21-1 and NMP22 appeared to be high enough so as to substitute urinary cytology. The diagnostic similarity between cytokeratins individually and in each type of patients might not recommend their simultaneous determination. The combined measurement of NMP22 and one cytokeratin marker (CYFRA 21-1 or UBC) appeared to be the most recommended.

Urinary tissue polypeptide-specific antigen for the diagnosis of bladder cancer.

OBJECTIVES: To evaluate the diagnostic characteristics of the urinary measurement of cytokeratin tissue polypeptide-specific antigen (TPS) for the detection of bladder cancer. METHODS: Three hundred thirty-five individuals in five groups were studied: group 1, subjects with microhematuria under suspicion for primary bladder cancer; group 2, patients being followed up with scheduled cystoscopic examinations; group 3, patients in follow-up receiving chemotherapy instillations; group 4, patients with other urologic diseases; and group 5, healthy subjects. Urine samples belonging to subjects from groups 1, 2, and 3 were collected immediately before cystoscopy. Additionally, patients from groups 2 and 3 were monitored with urinary TPS for a minimum period between two cystoscopies. TPS was measured by an enzyme immunosorbent assay. RESULTS: Receiver operating characteristic analysis gave a sensitivity of 64% and a specificity of 84% at a threshold value of 279 U/L. The positive and negative predictive value was 66% and 82%, respectively; accuracy was 77%. TPS could discriminate the presence of bladder tumor sooner than the scheduled cystoscopies in 9 of 19 follow-up patients with recurrence. False-positive results during follow-up were found in 112 urine samples, one third of which were associated with urinary tract infections. TPS did not appear to be specific for bladder cancer, with elevated results in 45% of patients from group 4, which might lead to clinical misinterpretation of urinary TPS results. CONCLUSIONS: Urinary TPS might provide additional information for the detection of bladder cancer as an adjunct to cystoscopy. Considering the false-positive rates, different urologic diseases should be ruled out before making clinical decisions on the basis of elevated urinary TPS results.

Serum zinc, copper, insulin and lipids in Alzheimer's disease epsilon 4 apolipoprotein E allele carriers.

BACKGROUND: Copper (Cu) and zinc (Zn) have been implicated in the development of Alzheimer's disease (AD) and, in this regard, Cu and Zn serum concentrations have been analysed but with inconclusive results. Serum insulin, glucose and cholesterol concentrations have been related to the apolipoprotein E genotype in non-AD populations. DESIGN: In this study, we have analysed the relationship between serum Cu, Zn, insulin, glucose and lipid parameters (cholesterol, triglycerides, apoA and apoB apolipoproteins) in AD and AD epsilon 4 apolipoprotein E carriers by multivariate analysis using logistic regression, including the variables that showed a significance of P < 0.05 in the bivariate analysis. RESULTS: The results obtained show that epsilon 4 apoE allele is an independent AD risk factor (OR = 6. 67, 95% CI = 2.59-17.16). In AD epsilon 4 apoE allele carriers, we found significantly higher Zn, Cu and insulin serum concentrations. Non-demented control subjects with at least one epsilon 4 apoE allele had the lowest serum insulin concentrations. There was no significant association between epsilon 4 apolipoprotein E allele and lipid parameters in the sample studied. CONCLUSIONS: In AD we have found a significant association between higher serum Zn, Cu and insulin concentrations and the presence of an epsilon 4 apoE allele, but only greater serum Zn concentration appears to be an independent risk factor associated with the development of AD.

Antiphosphatidylserine antibodies in patients with autoimmune diseases and HIV-infected patients: effects of Tween 20 and relationship with antibodies to beta2-glycoprotein I.

Antiphospholipid antibodies (aPL) react with negatively charged phospholipids, which may often be complexed with a protein cofactor such as beta2 glycoprotein (beta2GPI) and prothrombin. Cofactor requirements may be assessed by measuring antibodies to beta2GPI or by adding Tween 20 to some reagents in the assays for aPL (anticardiolipin and antiphosphatidyIserine). We have measured anticardiolipin antibodies (aCL), antiphosphatidylserine antibodies (aPS), and anti beta2 glycoprotein antibodies (abeta2GPI) in the serum of 10 normal subjects, 20 patients with systemic autoimmune diseases (SAD) diagnosed as having systemic lupus erythematosus (SLE) or antiphospholipid syndrome (APS), and 12 patients with HIV infection. Adding Tween 20 to aPS, the assay couldn't differentiate protein cofactor dependent from independent antibodies, but this can be done by measuring abeta2GPI (P= 0.0008). There was a significant correlation between aCL and a(beta)2GPI in the control group and in the patients with SAD, but not in the HIV-positive (HIV+) patients. After excluding the HIV+ patients, the best Spearman correlation was obtained between a(beta)2GPI and aCL (0.64, P< 0.0005). In 3 out of 7 patients with positive a(beta)2GPI and in 5 out of 6 patients with moderate or high positive aCL of the group of SAD, there was a history of venous thrombosis. The presence of moderate or high values of aCL either alone or together with a(beta)2GPI was significantly associated with a history of venous thrombosis (P < 0.05). Moderate or high aCL concentrations and their association with a(beta)2GPI seems to be useful for the assessment of the risk of venous thrombosis in unselected patients with SLE or APS.

Utility of a synthetic poly dT band included in a commercial blot assay to detect anti-DNA antibodies.

Systemic lupus erythematosus (SLE) patients exhibit anti-DNA antibodies with a heterogeneous pattern of individual specificity of binding. Likewise, the methods used for the measurement of anti-DNA antibodies exhibit a wide spectrum of binding avidities detection. We have evaluated the clinical utility of a band of synthetic poly dT included as an antigen in a recently commercialized blot system for antinuclear antibodies to detect anti-DNA antibodies. Sera from 45 individuals (36 patients with SLE, 9 without autoimmune disease negative for anti-nDNA by ELISA) were evaluated by the commercial immunoblot assay, ELISA for anti-nDNA, and conventional immunofluorescence using Crithidia lucillae substrate. Kappa statistics were used to determine the agreement between assays. The results obtained show a better agreement between positive bands for poly dT and anti-nDNA antibodies measured by IIF than by ELISA (Kappa index 0.64 vs. 0.44), although there are discrepant results. Likewise, positive bands for poly dT were obtained in patients with active SLE as assessed by decreased serum C3 concentration. We conclude that anti-poly dT reactivity reveals anti-nDNA antibodies of medium-high avidity, which show best disease activity.

Comparison and variation of different methodologies for the detection of autoantibodies to nuclear antigens (ANA).

Interest in the assessment of autoantibody specificity stems from the need for an autoantibody marker capable of predicting clinical events in autoimmune disorders. However, the multiplicity of epitopes present on autoantigenic particles, the quantitative and qualitative heterogeneity of autoantibodies, as well as the nature of the tests, mean that each of the assays used in their determination have different characteristics. The aim of this study was to compare the specificities of different ANAs using four commercial assays. The routine method used for the detection of ANA is indirect immunofluorescence on Hep-2 cells. The assays used were: counterimmunoelectrophoresis (CIE), enzyme-linked immunosorbent assay (ELISA), and two immunoblotting assays. Kappa statistic was applied to evaluate the consistency between tests. Kappa index is a measure of agreement between categorical data. Kappa has a maximum of 1.00 when the agreement is perfect, a value of zero indicates no agreement better than chance, and negative values show worse than chance agreement. For SS-B antibodies, there was a good concordance between all four methods used (Kappa 0.66-0.74). For anti RNP antibodies, the results for CIE/ELISA (Kappa 0.60) were consistent as were the two immunoblot methods (Kappa 0.69). For anti Scl-70 (topoisomerase I) antibody, results from the ELISA and CIE methods were totally consistent (Kappa 1.00). In spite of the high prevalence of anti SS-A/Ro antibodies, the agreement between the methods was poor, without statistical significance. Finally, for Sm antibodies, more consistent results were obtained between CIE/ELISA (Kappa 0.51) and between one of the immunoblotting methods and ELISA (Kappa 0.54). In conclusion, CIE concurs mostly with ELISA for anti-RNP, Scl-70, Sm and SS-B antibodies, but with some disagreement for SS-A antibodies.

[Genotype and phenotype of apolipoprotein E in patients with Alzheimer's disease in Castille and Leon]. / Genotipo y fenotipo de la apolipoproteína E en enfermos de Alzheimer en Castilla y León.

We determined the variants of the apolipoprotein E (apo-E) in a sample taken from a castellano-leonesa population with Alzheimer's disease (AD). The prevalence of the allele E-4 is 0.33 in AD and 0.12 in the control group. This results allow us to estimate that the risk of suffering from the disease is higher when the patients have an allele E-4. A significant correlation was found between the presence of the allele E4 and the AD (p < 0.005).

Multicentre evaluation of the Boehringer Mannheim Hitachi 911 system for homogeneous immunoassays.

A multicentre evaluation of the new analyser, Hitachi 911, is reported for three different classes of homogeneous immunoassays (latex assays, immunoprecipitation assays, and CEDIA assays). The evaluation protocol follows ECCLS, IFCC and NCCLS guidelines. Using patient samples and commercial controls, within run and between run coefficients of variation were less than 3% in most cases, but as high as 9.7% for some CEDIA and latex assays. All the assays were linear, either in the reference or the therapeutic range of the analytes. No interference by haemolysis, lipaemia or icterus was observed. The methods were compared with other commercial methods. Coefficients of correlation were higher than 0.94 for all the methods. However, there were differences of slope and intercept for rheumatoid factor, apolipoprotein A-I and apolipoprotein B. On the Hitachi 911, all of the eight methods give precise and accurate results, and compare well with other established methods on immunoassay dedicated analysers. The discrepancies observed could be ascribed to current problems of immunoassay standardization.

Carbohydrate antigen 15-3 and mucinous carbohydrate antigen immunoreactivities in human seminal plasma.

Carbohydrate antigen 15-3 (CA 15-3) and mucinous carbohydrate antigen (MCA) immunoreactivities were detected in human seminal plasma. Mean values for CA 15-3 (8.2 +/- 3.7 U/ml, range 2.6 - 18.4 U/ml) and MCA (13.8 +/- 8.2 U/ml, range 2.1-31.9 U/ml) in the seminal plasma were of the same magnitude as that found in serum. No correlation was obtained between seminal plasma, either CA 15-3 or MCA immunoreactivities, and volume of seminal plasma, sperm count or percent of motile spermatozoa. Seminal plasma CA 15-3 and MCA levels were significantly (p less than 0.001) correlated (r = 0.55). The nature and origin of CA 15-3 and MCA immunoreactivities in human plasma are unknown.

Role of vasoactive substances in the segmentary vasomotor response following spinal cord stimulation. An experimental study.

It is presumed today that spinal cord stimulation induces local delivery of vasoactive substances, such as prostacyclins, histamine, substance P, and vasoactive neuropeptides, in the perivascular environment and the vascular wall to mediate the segmental vasodilator response. To investigate this mechanism, 9 dogs were subjected to low thoracic spinal cord stimulation. Venous and arterial blood samples from the paraesthesic area in the lower limbs were obtained before and 120 min after stimulation to measure changes in the plasma concentration of vasoactive intestinal peptide, substance P, and histamine. The results were compared with those obtained from vessels of the upper limbs. Blood flow changes following stimulation were recorded by electromagnetic flowmeters. Local arterial vasoactive intestinal peptide showed a mean increase of 33% after 60 min of stimulation. Changes concerning substance P were inconclusive. Local arterial and venous histamine concentrations increased 26 and 29%, respectively, after 60 min of stimulation.

Acid-base balance and electrolyte concentration in blood during graded exhausting exercise in non-trained subjects.

Venous acid-base balance and electrolyte concentration during step-graded and exhausting exercise with a two-minute steady-state has been studied in a group of non-trained young men. The results showed a significant decrease in pH, pCO2 and bicarbonate and a significant increase in lactate, potassium, inorganic phosphate and proteins during the exercise. The supervening acidosis had a large anion gap that was of proportion with the increase in lactate values. We suggest that the total sum of other anions such as proteins, phosphate, pyruvate, citrate, free fatty acids and aminoacids, as well as sodium-hydrogen exchange could account for this acidosis.