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At least 1,603 records · Page 89Linked to original sources
PubMed1976

[Isolation of a toxicogenic strain of the fungus, Aspergillus flavus, and characteristics of the produced aflatoxins].

The authors demonstrate the production of the B1 aflatoxin by means of a strain of the fungus Aspergillus flavus which was captured on cereal feed in spring 1975. Besides the production of the mycotoxin, this fungus strain showed a very quick and intensive growth and development, in comparison with the laboratory strains of Aspergillus flavus. The obtained and isolated aflatoxin B1 could be identified by chromatography and spectral photometry only when the fungus strain was cultivated on a suitable substrate where it showed the lowest producting of the distrubing fluorescent metabolism by-products. That finding led to the conclusion that in some cases it is necessary, besides the classically used procedure of the diagnosis of aflatoxicosis, to require also the isolation of the possibly present strain of Aspergillus flavus and--after its recultivation in pure cultures on suitable media--the determination of aflatoxin production connected with their physical and chemical identification.

Aflatoxins↗
PubMed1993

Development and evaluation of a reagent carrier with a new reaction sequence for the determination of creatinine in blood, plasma, serum and urine.

After a short outline of the history of creatinine determination methods we describe the development of a dry-reagent-carrier system for the reflometric determination of the creatinine concentration in blood, plasma, serum and urine (Reflotron Creatinine (new)). The method is based on a sequence of enzymatically catalyzed reactions producing H2O2, but which in contrast to the previously used procedure do not lead to the formation of creatine as an intermediate. Hence, pretreatment of sample material to eliminate endogenous creatine is no longer necessary. In the indicator reaction, use is made of an imidazole derivative as the chromogen. The dye formed in the presence of peroxidase can be measured by reflectance photometry beyond the long-wave absorption bands of haemoglobin and bilirubin at 642 nm. We present in detail the results of the multicentre evaluation of the analytical properties of this new test principle. The data obtained show that Reflotron Creatinine (new) correlates well with the routine method Creatinine PAP, which was used as a comparison method, with respect to accuracy and precision and even surpasses it with respect to specificity. Advantages over the first generation of Reflotron Creatinine are: shorter reaction time, longer stability of the reagent carrier, no interference by bilirubin and reduced interference by haemoglobin.

Blood Chemical Analysis↗
PubMed1993

[Effect of different amounts of dietary sodium on plasma atrial natriuretic peptide (ANP)in essential salt sensitive hypertension].

The aim of the study was an evaluation of the effect of different dietary sodium intake on: blood pressure, plasma concentration of atrial natriuretic peptide (ANP), cyclic guanosine monophosphate (cGMP), aldosterone (ALDO) and plasma renin activity (PRA) in patients with primary sodium sensitive arterial hypertension class I acc. to WHO criteria. Thirteen patients, non treated, with sodium sensitive arterial hypertension aged 30 +/- 8 years participated in the study. Blood samples were taken three times: in 5th day of normal sodium intake (100-120 mmol Na per 24 h); in 5th day of low sodium diet (10-20 mmol Na per 24 h); in 5th day of high sodium diet (200-220 mmol Na per 24 h). During 24 hours before each blood sampling the urine was collected and sodium and potassium excretions were evaluated. Concentrations of ANP, cGMP, ALDO in plasma and PRA were determined by radioimmunoassays and serum sodium and potassium concentration by flame photometry. Significant (p < 0.05) diminution of blood pressure, plasma ANP and cGMP concentrations and the increase of plasma ALDO and PRA after sodium restriction when compared to normal sodium diet were found. High sodium diet resulted in significant increase of blood pressure, plasma ANP and cGMP concentrations to the values comparable with these on normal sodium diet. On the contrary PRA and plasma ALDO concentration decreased (p < 0.001) below the values during normal sodium diet. Urinary sodium excretion corresponded to dietary sodium intake during all diets.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Modification of carotid chemoreceptor-induced changes in renal haemodynamics and function by carotid baroreflex in dogs.

1. Mongrel dogs were anaesthetized with thiopental sodium and chloralose and artificially ventilated. The carotid sinus regions were vascularly isolated and perfused either with arterial or mixed (arterial and venous) blood (PO2, 44.2 +/- 3.3 mmHg, mean +/- S.E.M.) to stimulate the chemoreceptors. Cervical vagosympathetic trunks were ligated and atenolol (2 mg kg-1, I.V.) was given in all dogs and gallamine triethiodide (3 mg kg-1 h-1, I.V.) was given in two dogs. Renal blood flow was measured by an electromagnetic flowmeter, glomerular filtration rate by creatinine clearance, sodium excretion by flame photometry and solute excretion by osmometry. The viability of the preparations was tested by recording total vascular capacitance responses to stimulation of carotid baro- and chemoreceptors. 2. In eleven tests in seven dogs at a constant aortic pressure of 88.9 +/- 2.6 mmHg stimulation of carotid chemoreceptors at a high carotid sinus pressure (194.0 +/- 3.6 mmHg) resulted in significant increases in urine flow of 22.8 +/- 3.0%, urinary sodium excretion of 30.7 +/- 5.2%, fractional sodium excretion of 35.3 +/- 18.6%, osmolar excretion of 17.5 +/- 4.1% and a decrease in free water clearance of 30.8 +/- 3.1% without significant changes in urinary sodium concentration, renal blood flow, glomerular filtration rate, and filtration fraction. 3. In seventeen tests in these seven dogs at a constant aortic pressure of 94.0 +/- 2.2 mmHg, stimulation of carotid chemoreceptor at a low carotid sinus pressure (72.0 +/- 1.3 mmHg) resulted in significant decreases in renal blood flow of 10.6 +/- 2.5%, glomerular filtration rate of 19.6 +/- 6.8%, filtration fraction of 13.2 +/- 5.5%, urine flow of 23.4 +/- 4.1%, urinary sodium concentration of 20.3 +/- 4.1%, urinary sodium excretion of 38.5 +/- 4.6%, fractional sodium excretion of 20.2 +/- 7.7%, osmolar excretion of 23.9 +/- 4.0% and an increase in free water clearance of 23.1 +/- 2.5%. 4. The results show that moderate stimulation of carotid chemoreceptors at a low carotid sinus pressure, when the activity in renal nerves is high and blood volume is low, can produce significant reflex decreases in renal haemodynamic and functional variables. However, at a high carotid sinus pressure when the renal sympathetic activity is low and blood volume is high, carotid chemoreceptor stimulation produces diuresis and natriuresis but no change in renal haemodynamics.

Animals↗
PubMed1993

Differences in serum potassium concentrations in normal men in different geographic locations.

Hypokalemia has been associated with the taking of gossypol, a potential oral antifertility drug for men. Because the frequency of this response differed in different parts of the world, this study was done to learn if "normal" serum [K+] also differed. [K+] was measured by flame photometry in serum from apparently normal men from Austria (n = 30), China (53), Brazil (100), the Dominican Republic (38), and the US (103), and in plasma from Nigerian men (82). The mean (SD) for [K+] in Chinese men, 3.82 (0.27) mmol/L, was lower than that in Brazilians [4.06 (0.29) mmol/L], Austrians [4.14 (0.44) mmol/L], Dominicans [4.37 (0.33) mmol/L], or Americans [4.38 (0.37) mmol/L]. Apparently there are regional differences in average serum [K+], with men in China having lower serum [K+] than men elsewhere. This may predispose them to hypokalemia.

Adolescent↗
PubMed1976

Quantitation of enzymes in tissue sections by estimation of hydrolytic activity and antigenic determinants.

The method and instrumentation for the analysis of enzyme activity and of fluorescent antibody of antigen binding is described. It is based on the microscopic photometry of stain intensities per area of functional units. Thus it was shown that the concentration of aminopeptidase (EC 3.4.2.1) per area in procimal tubule of kidney from pig and mouse is constant. In contrast to the pig the tubules from the outer medulla of the mouse contained twice as much enzyme as those from the cortex. A non constant concentration of aminopeptidase per area was found in crypts of duodenum and in stimulated macrophages.

Aminopeptidases↗
PubMedDate not supplied

[Preparation and testing of buffers for fibrinogen].

Chloride-citrate-glucose solution was used in fibrinogen preparation for intravenous administration. Concentrated hydrochloric acid previously used for preparation of buffers for fibrinogen has been replaced by the diluted one enabling easier and more precise buffer pH regulation and faster fibrinogen dissolution. Procedure for spectrophotometric determination of the total citrate ion buffer system, sodium-citrate and citric acid was developed. Obtained results were within the prescribed limits but the ones obtained by officinal titration in non-aqueous medium were significantly decreased. Glucose was determined before sterilization by polymetric, and after sterilization by iodometric procedure. Chloride content was determined by coulometric titration and sodium content by flame photometry. Used analytic methods are simple and obtained results accurate and reproducible.

Buffers↗
PubMed1995

Quantitation in immunohistochemistry. A research method or a diagnostic tool in surgical pathology?

Quantification of immunohistochemical methods is feasible by two ways, namely microscope photometry and TV densitometry. The rapid progress of computer technology argues largely in favour of the second system. From the immunohistochemical methods either ABC, the PAP or the APAAP method should be chosen. Diaminobenzidine is the H2-donor of choice for the peroxidase mediated systems, whereas Fast Red TR or Neufuchsin can be used with the APAAP system. The test efficiency, and the precision of measurements should be investigated in each laboratory doing quantitative immunohistochemistry. Low levels of coefficients of variation (CV) should be reached for one field of interest. Examples of introducing the method of quantitative immunohistochemistry in a routine laboratory are discussed. The demonstration of either a steroid receptor or a proliferation marker, such as PCNA or Ki67, are seemingly of the greatest clinical interest.

Humans↗
PubMed1995

Development of a HPLC-system for quantitative measurement of lidocaine and bupivacaine in patients plasma during postoperative epidural pain therapy.

A HPLC method was developed for the simultaneous quantitative analysis of lidocaine and bupivacaine in plasma, with bupivacaine serving as the internal standard for the assessment of lidocaine and vice versa. The samples are prepared by diethyl ether-extraction of the alkalified plasma and re-extraction using diluted sulphuric acid. This allows the elimination of interfering medication and plasma proteins. The prepared samples are chromatographed with a Merck LiChroCART Superspher 60 RP-select B cartridge column, the local anesthetics are detected using UV-photometry and the concentration is calculated by comparing the peak areas of the analyzed substance and the internal standard. Using a sample volume of 1 ml plasma, concentrations of approximately 2.5 micrograms/ml and 1 microgram/ml can be analyzed with a 95%-confidence interval of 2.5% or 5%, respectively. At higher or lower concentrations, accurate results can be obtained using smaller or larger plasma samples. The evolved analytical method allows the rapid and simple determination of lidocaine and bupivacaine plasma levels at a wide range of concentrations. It is suitable for research purposes as well as for routine analyses.

Analgesia, Epidural↗
PubMed1995

Chronic but not acute Li+ treatment prevents behavioral depression in rats.

The effect of lithium administration on the learned helplessness model of depression was investigated. Female Wistar rats (190-210 g) received either tap water alone (N = 156) or 20 mM LiCL provided chronically (30 days; N = 127) or acutely (5 days; N = 22) in the drinking water. Three days before the end of treatment, each group was divided into two subgroups which received either inescapable shock (IS) or no shock (NS) treatment in shuttle boxes. All groups were subsequently submitted to an escape test on the following day and then sacrificed one day after the escape test, when blood samples were taken to measure serum Li+, Na+ and K+ concentrations by flame photometry. There were no significant differences in serum Na+ amongst the 4 groups. Chronically treated NS and IS rats both presented an increase in serum K+ compared to the control rats. The IS and not the NS chronically treated rats presented increased serum Li+ levels which cannot be accounted for in terms of differences in Li+ intake. The IS group treated chronically with lithium had a better escape performance than the IS group receiving either tap water or acute Li+ administration. We conclude that chronic but not acute Li+ treatment at a serum level within the prophylactic range (0.5 mEq/l) is able to prevent learned helplessness in the rat. These results agree with the data obtained in clinical practice indicating that Li+ is only effective after chronic administration and that Li(+)-induced hyperkalemia is a side effect.

Analysis of Variance↗
PubMed1995

Determination of amplification level of the c-erbB-2 proto-oncogene in human breast carcinomas: a comparative study between non-radioactive and radioactive labelling.

A quantitative method of polymerase chain reaction (PCR) using both digoxigenin and radioactive labelled probes has been used for the detection of the c-erbB-2 proto-oncogene amplification in breast carcinomas with formalin-fixed paraffin-embedded tissue sections. c-erbB-2 proto-oncogene amplification has been demonstrated in 14 infiltrating ductal carcinomas. The technique consisted of the co-amplification of c-erbB-2 and IFN-gamma (interferon-gamma) genes. The latter was considered as a single copy gene per genome-equivalent. The aim of this study was to compare two quantitative PCR techniques based on the incorporation of either digoxigenin-11-dUTP or 32P-dCTP, during amplification. For the colorigenic method, using the Dig system, after electrophoresis and transfer, the specific bands were revealed with a chromogenic substrate of phosphatase. Their intensity estimated by scanning photometry following blot transparisation. After electrophoresis, the radioactive gel was submitted to radioautography and the band intensities evaluated by scanning spectrophotometry. For the 14 samples, a good agreement between both methods was noted. The colorigenic method is a valuable alternative to radiolabelling due to: i) time saving, ii) reagent conservation, iii) safe manipulation and iv) sensitivity of the same order for both methods.

Base Sequence↗
PubMedDate not supplied

Determination of dietary fiber and carbohydrate composition of foods by a modified version of the Englyst method.

A modified version of the Englyst procedure for determination of dietary fiber and carbohydrate fractions of foods is described. The method is based on hydrolysis of separated fractions and capillary gas chromatographic (GC) analysis of derivatized monomer sugars, UV photometry of uronic acids, gravimetric determination of residue, and analysis of nitrogen content of the residue by using a C, H, N elemental analyzer. Modifications of fractionation, derivatization, and GC procedures are discussed. Rigorous sample preparation is required for reproducibility of 200 mg test portions. Contaminants interfering with chromatography must be minimized. Results for reference samples (wheat bran and Buerre Bosc pears) and white and whole meal bread agree with literature values.

Bread↗
PubMed1977

Sodium and potassium content of cataractous human lenses.

The sodium and potassium content of human senile cataractous lenses was investigated by flame photometry. A parallelism was found between the severity of the senile cataractous disorder and the increase of sodium and decrease of potassium content of lenses. The changes in ion concentration were not entirely continuous; gaps were found for both cations in a certain concentration range. The involvement of lens proteins in maintaining the gradients for sodium and potassium is also discussed.

Aged↗
PubMed1996

Laboratory work flow analysis and introduction of a multi-functional analyser.

Laboratory work flow analysis was performed in order to define guidelines for improved laboratory organisation and efficiency. All activities were monitored from the moment a laboratory test was requested until the result was reported and received. Detailed information was collected on numbers of samples and tests, work-stations and sample splitting, number of staff and laboratory costs and management. From the data thus obtained requirements for optimal reorganisation could be developed. Reduction of work-stations appeared to be of primary importance. This could be achieved by replacement of seven different work stations by instruments for multi-functional analysis (Cobas Integra) in the department of routine clinical chemistry. Effects of reorganisation were evaluated by repeated work flow analysis. The multifunctionality of the analysers (photometry, turbidimetry, ion selective electrodes and fluorescence polarisation) provides opportunities for efficient work structuring, avoiding the need for sample splitting, distribution of sub-samples and performing analyses at different work stations. Manual and clerical errors could thus be reduced. Laboratory service to clinicians was improved by reduction of turnaround times to such an extent that all test results are reported within 60 minutes (stat service) even during peak hours. Laboratory costs were reduced by decreasing the number of laboratory staff and work-stations. Both clinicians and patients expressed great satisfaction with the effects of this reorganisation, for which work flow analysis appeared to be an indispensable instrument.

Blood Chemical Analysis↗
PubMed1996

Investigation into intraerythrocytic and extraerythrocytic acid-base and electrolyte changes after long-term ammonium chloride administration in dogs.

OBJECTIVES: To investigate the effect of ammonium chloride-induced urine acidification on acid-base status (ABS) of blood, plasma, and erythrocytes, and to compare the diagnostic value of acid-base analysis for erythrocytes with that for blood and plasma. DESIGN: Ammonium chloride (100 mg/kg of body weight) was administered orally every 12 hours for 8 consecutive days. The ABS was determined daily in venous blood, plasma, and lysed, packed erythrocytes (erythrolysate) and in urine. In plasma and erythrocytes, concentrations of sodium Na+) and potassium (K+) were analyzed. ANIMALS: 16 clinically normal (8 treated and 8 control dogs. PROCEDURE: The acid-base analysis (standard pH, standard bicarbonate concentration, base excess, and carbon dioxide tension) in blood, plasma, and erythrocytes was determined by use of the CO2, O2 gas equilibration method. Determination of urine ABS (pH, concentrations of acids and bases, net acid-base excretion, base-acid quotient) was performed by titration methods. Determination of concentrations of Na+ and K+ in erythrocytes was performed by flame photometry, and in plasma, by use of ion-specific electrodes. RESULTS: Ammonium chloride caused metabolic acidosis in blood and plasma, but no change of ABS in erythrocytes. The concentrations of K+ in plasma and erythrocytes did not change in treated dogs; however, the concentrations of Na+ in plasma and erythrocytes decreased significantly (P < 0.05) after ammonium chloride administration. Urinary acid excretion increased significantly (P < 0.05) in treated dogs; urine pH was between 4.51 and 5.49 at all times. CONCLUSIONS: Ammonium chloride administration (100 mg/kg, PO, q 12 h) causes substantial blood and urine acidification but does not influence erythrocyte ABS. In this study, determination of erythrocyte ABS did not provide any additional benefit in diagnosing metabolic acidosis, compared with analysis of blood.

Acid-Base Equilibrium↗
PubMed1995

[Glossary of terms used by radiologists in image processing].

We give the definition of 166 words used in image processing. Adaptivity, aliazing, analog-digital converter, analysis, approximation, arc, artifact, artificial intelligence, attribute, autocorrelation, bandwidth, boundary, brightness, calibration, class, classification, classify, centre, cluster, coding, color, compression, contrast, connectivity, convolution, correlation, data base, decision, decomposition, deconvolution, deduction, descriptor, detection, digitization, dilation, discontinuity, discretization, discrimination, disparity, display, distance, distorsion, distribution dynamic, edge, energy, enhancement, entropy, erosion, estimation, event, extrapolation, feature, file, filter, filter floaters, fitting, Fourier transform, frequency, fusion, fuzzy, Gaussian, gradient, graph, gray level, group, growing, histogram, Hough transform, Houndsfield, image, impulse response, inertia, intensity, interpolation, interpretation, invariance, isotropy, iterative, JPEG, knowledge base, label, laplacian, learning, least squares, likelihood, matching, Markov field, mask, matching, mathematical morphology, merge (to), MIP, median, minimization, model, moiré, moment, MPEG, neural network, neuron, node, noise, norm, normal, operator, optical system, optimization, orthogonal, parametric, pattern recognition, periodicity, photometry, pixel, polygon, polynomial, prediction, pulsation, pyramidal, quantization, raster, reconstruction, recursive, region, rendering, representation space, resolution, restoration, robustness, ROC, thinning, transform, sampling, saturation, scene analysis, segmentation, separable function, sequential, smoothing, spline, split (to), shape, threshold, tree, signal, speckle, spectrum, spline, stationarity, statistical, stochastic, structuring element, support, syntaxic, synthesis, texture, truncation, variance, vision, voxel, windowing.

Diagnostic Imaging↗
PubMed1995

Childhood obesity elevates blood pressure and total cholesterol independent of physical activity.

OBJECTIVE: To compare the habitual physical activity, blood pressure, total cholesterol levels of obese and non-obese matched children. SUBJECTS: 546 obese children (BMI and sum of skinfolds > or = 90% tile) were matched for gender, race, age, and height (within 2 cm) with non-obese controls for a total sample of 1092 children. MEASUREMENTS: Systolic (BPsys) and diastolic (BPdia) blood pressure by mercury sphygmomanometer, total cholesterol by reflectance photometry, and physical activity by questionnaire. RESULTS: Mean comparisons indicated the obese children, regardless of gender, had higher BPsys (108 +/- 11 vs 104 +/- 10 mm Hg, P = 0.0001), BPdia (70 +/- 9 vs 68 +/- 8 mm Hg, P = 0.002), and greater total cholesterol levels (4.47 +/- 0.80 vs 4.11 +/- 0.75 mmol/L, P = 0.0001) than the non-obese subjects. Self-reported physical activity scores were not significantly different when comparing the obese and non-obese children. Correlations between self-reported activity and cholesterol or blood pressure were all very low and not significant (r < or = 0.06). CONCLUSION: These results suggest that childhood obesity is associated with higher blood pressures and greater circulating cholesterol levels independent of physical activity levels.

Aging↗
PubMed1997

Multiple G-protein involvement in parathyroid hormone regulation of acid production by osteoclasts.

The involvement of multiple G-proteins in parathyroid hormone regulation of acid production was demonstrated in a highly enriched osteoclast population. Osteoclasts were isolated from the endosteum of 2.5 to 3-week-old chicken tibia using sequential enzymatic digestion. Single cell analysis of acid production was accomplished using microscope photometry and vital staining with acridine orange, a hydrogen ion concentration sensitive fluorescent dye. Lithium chloride, an uncoupler of G-proteins from their respective receptors, blocked parathyroid hormone stimulated production of acid. Cholera toxin, which permanently activates Gs-proteins, mimicked PTH stimulation. Pertussis toxin, which prevents receptor interaction with Gi- and Go-proteins, blocked both 10(-8) M and 10(-11) M PTH stimulated acid production, suggesting that the pertussis toxin-sensitive G-protein is utilized at both PTH concentrations. Immunoblots of osteoclast plasma membrane proteins, using a panel of antibodies generated against specific G-protein alpha subunits, revealed a 48 kDa Gs alpha, a 41 kDa Go alpha, a 34 kDa Gi alpha-3, and a unique 68 kDa G alpha subunit, with the 41 kDa and 34 kDa bands being the most intense. Immunoblots of osteoblast plasma membrane proteins had a substantially different profile with the most intense bands being a Gs alpha (48 kDa) and a Go alpha (36 and 38 kDa). The studies suggest the utilization of at least two different G-proteins in the parathyroid hormone regulation of acid formation by osteoclasts, a Gs and a pertussis toxin-sensitive G-protein (Go and/or Gi alpha-3).

Acids↗