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PubMed1992

[Observations on the cost effectiveness of various methods of electrolyte determination].

New analytical methods have to be considered also with respect to their economic efficiency. Here we present the application of an economic analysis based on the rules of applied economics in our institute for clinical chemistry and laboratory medicine. We started with an analysis of laboratory structure and economic efficiency in 1988, which since then has been followed by a continuously performed laboratory controlling system. The results of unit costing show the different cost groups, which add up to the cost of a single electrolyte determination. Regarding the transferability of our data to other laboratories, one has to consider that the main cost groups besides personnel cost are the apportionment of the overhead cost and the depreciation cost; both may vary markedly between each laboratory. Variable cost (reagents and consumables) differ widely from flame photometry to enzymatic electrolyte determination, but they amount only to 3-15% of the total cost.

Blood Chemical Analysis↗
PubMed2004

[MDR-reversing effect of two components of catechin on human hepatocellular carcinoma BEL-7404/Adr in vitro].

BACKGROUND & OBJECTIVE: Catechin is composed of a variety of components,some of which have anti-cancer activity. There was no report on effect of catechin on the multidrug resistance of hepatocellular carcinoma so far. The aim of this study was to investigate the MDR-reversing effect of two components of catechin on human hepatocellular carcinoma BEL-7404/Adr in vitro and its potential mechanism. METHODS: MTT was used to test the toxicity of the two components of catechin. The concentration of the drugs inside the cells was determined by fluorospectro-photometry and the expression of MDR1 was measured by RT-PCR. RESULTS: The inhibition rates of BEL-7404/Adr caused by two components of catechin were less than 10% under the dose of 100 mg/L. Epicatechin gallate (ECG) in 60 mg/L or epigallocatechin gallate (EGCG) in 14 mg/L has slight cytotoxicity, but they could decrease the IC(50) of adriamycin (ADM) for BEL-7404/Adr from 36 mg/L to 2.3 mg/L or 1.9 mg/L, respectively, and the reversing folds were 15.8 and 19.2, respectively. The combined administration could increase the concentration of ADM in BEL-7404/Adr cells from 0.76 microg/10(8) cells-2.55 microg/10(8) cells to 2.04 microg/10(8) cells -9.28 microg/10(8) cells (P< 0.01). The expression of MDR1 was down-regulated by 27.6% and 41.3%, respectively. Furthermore, EGCG is the stronger one. CONCLUSION: ECG and EGCG can reverse the multi-drug resistance of human hepatocellular carcinoma in vitro. The possible mechanism is related to down-regulating the expression of MDR1 and raising the concentration of drugs inside the cells.

Carcinoma, Hepatocellular↗
PubMedDate not supplied

Particle distribution in low-volume capillary-loaded chambers.

Accurate determination of sperm concentration in fluid suspension is a critical component in a semen analysis. Inaccurate estimations can lead to misinterpretation of the spermiogram and, in the case of livestock production, can lead to faulty insemination doses, which can adversely affect stud power, fertility, fecundity, and cost effectiveness of breeding programs. Capillary-loaded slides, like the hemacytometer, have been the standard for calibration of other concentration estimation modalities such as photometry, Coulter counter, flow cytometry, and computer-automated semen analysis (CASA). Single-use capillary-loaded slides, much smaller than the hemacytometer, are frequently used by many of the current CASA systems. As the use of CASA increases, more field reports are suggesting differences between CASA results and hemacytometry. In this article, we establish that these differences are, in large part, due to the Segre-Silberberg effect, which occurs during Poiseuille flow in high-gradient fluid flow in thin capillary-loaded slides. We develop the theory of this phenomenon and derive the scaling and significance of the effect. Finally, we graphically provide a means for predicting the necessary compensation factor when using capillary-loaded slides to determine sperm concentration.

Animals↗
PubMed2004

[Kinetic study on collagen mineralization by ultraviolet absorption spectra].

The mechanism of collagen mineralization was studied by ultraviolet photometry method. The reaction solution was determined using ultraviolet-visible spectrophotometer by the method of repeat scanning wavelength. The recorded curves provided the spectroscopic and kinetics information of the reaction solution. It was found that the wave trough appeared on the step-like kinetic curve of mineralization of collagen. With the increase in initial concentration of calcium phosphate, the wave trough intensity increased and its position moved forward. The curves of scanning wavelength at different time showed different patterns. By analyzing the change in scanning wavelength curves, and the X-ray diffraction spectra of specimens before and after the wave trough position (the specimens were obtained by quickly freezing the solution and freeze-drying), it was suggested that gelation and phase separation occurred during the process of collagen mineralization. Collagen molecules loading calcium were cross-linked by newly formed DCPD in a "point to point" mode. The phase separation occurred in the fluid-filled space and the wave trough occurred in the ultraviolet absorption spectrum. Based on the mechanism the varieties of phenomena in the ultraviolet absorption spectrum during collagen mineralization were explained.

Absorption↗
PubMedDate not supplied

Metabolism and disposition of trifluoperazine in the rat. I. A thin-layer chromatographic method for the measurement of trifluoperazine and its metabolites in rat tissues.

A method has been developed for quantitative measurement of trifluoperazine and its metabolites, 7-hydroxytrifluoperazine and desmethyltrifluoperazine, in rat organs. Trifluoperazine sulfoxide could also be assayed, but it proved to represent a very minor part only of total biotransformation products in tissues. Alkalinized tissue homogenates were extracted with di-isopropyl ether. Following removal of the bulk of lipids, the compounds to be quantitated were separated by thin-layer chromatography and measured by ultraviolet reflectance photometry on the plates. In recovery experiments, the method proved to possess a high reproducibility. The sensitivity limit for quantitative determination was about 0.1 nmol per extract, and the limit of detectability was 0.025-0.05 nmol. The applicability of the method was shown by analyzing the tissues of rats that had received 12.3 micronmol of trifluoperazine, ip, per kg.

Animals↗
PubMed2006

[Preparation and characterization of superparamagnetic iron oxide nanoparticles].

OBJECTIVE: To determine the physical and magnetic properties of superparamagnetic iron oxide (SPIO) nanoparticle prepared in our laboratory and evaluate its possibility for use as contrast agents in magnetic resonance imaging (MRI). METHODS: The SPIO nanoparticle was obtained by means of classical coprecipitation in dextran solution and its size determined by electron microscopy and photon-correlation spectroscopy. The iron content was determined by phenanthroline photometry, and T(2) values as well as relaxivity evaluated with a clinical MR system at 1.5T. RESULTS: Dextran-coated magnetite particles with a hydrodynamic diameter of 85.9 nm were prepared. The iron core size was 15 nm and the formation of Fe(3)O(4) crystal in SPIO nanoparticles was confirmed by X-ray diffraction (XRD) analysis. These particles possessed some characteristics of superparamagnetic and show a smaller spin-spin relaxation, with relaxivity and saturation magnetization of 0.1567 mmol(-1)/ms(-1) and 80 emu/g Fe, respectively. CONCLUSIONS: A stable SPIO nanoparticle with a dextran coating have been developed, and in vitro evaluation of its physical and magnetic properties suggests its potential for use as the contrast agent in MRI.

Humans↗
PubMed1991

[The role of the sodium gradient in the efflux of Ca++ ions from the smooth muscle cells of the ureter].

The role of sodium in calcium active transport from the ureter muscle, preliminarily enriched in these ions, was studied in large ouabain concentration (10(-4) mmol/l) for complete inhibition of the Na(+)-K(+)-pump. The determination of intracellular concentrations of sodium and calcium ions (by flame photometry and isotopic analysis, resp.) showed that a fast decrease of intracellular calcium content was accompanied by an increase of intracellular sodium. With high sodium ions concentration in medium (above 100 mmol/l), the velocity of the decrease in intracellular calcium content reached the maximal value, the efflux of additional enriched calcium ions occurring within 10-15 min. The decrease of intracellular calcium content was in sigmoidal dependence on the concentration of sodium ions in the medium. The electrogenic Na(+)-Ca(++)-exchange system seems to play a major role in calcium-enriched muscles for the decrease of intracellular calcium content.

Animals↗
PubMed1991

Urinary kallikrein excretion in chronic renal disease with respect to salt intake and renal reserve.

In order to investigate the status of urinary kallikrein excretion (UKE) in various chronic renal diseases, we measured the UKE in 56 patients with chronic renal diseases. They ranged in age from 19 to 80 with 26 males and 30 females. Among them were 31 patients with primary glomerulonephritis (GN) without nephrotic syndrome, 8 with nephrotic syndrome, 10 with various renal diseases in the azotemic stage, 3 in the uremic stage and 4 with type I renal tubular acidosis (RTA) due to Sjögren syndrome. The primary GN patients who were on a low salt diet were classified as group II GN, while those who partook freely of salt were classified as group I GN. Thirty-six normal volunteers were enrolled as controls. Kallikrein activity was determined by enzymatic hydrolysis of synthetic chromogenic substrate S-2266. Urinary electrolytes were measured by flame photometry. The results showed that UKE was lower in patients with group I GN, azotemic or uremic patients and in patients with RTA, as compared with normal controls. If UKE was corrected by creatinine clearance (CCr), the UKE/CCr ratio was still lower in group I GN patients, but became higher in patients with azotemia and uremia. The UKE/CCr ratio was not different from that of controls or patients with RTA. In nephrotic patients, the UKE and UKE/CCr ratio were both higher than that for normal controls. However, in group II GN patients, neither UKE nor the UKE/CCr ratio differed from that of controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[Determination of the erythrocyte count using a microcolorimeter].

Red cell count is estimated with the use of a MKMF-1 microcolorimeter. 10 ml of Gower's solution are used; 0.02 ml of blood are added to this solution. Photometry of red cell suspension is carried out in a cuvette with a 0.5 cm optic route at lambda 610 nm. Microampermeter data are read from the optic density D scale. The D value is substituted into the formula: red cell count (RC) = K.D.10(6), where K coefficient is found experimentally by measuring the D and by estimating red cell count in microscopy, and is equal to 33.3. This formula permits estimating red cell count in 1 microliter of blood.

Colorimetry↗
PubMed1990

[Immunohistologic photometric quantification of pyruvate kinase content of rat tumors].

86 benign and malignant tumours were investigated histologically and immunohistologically. Staining intensity was measured by scanning-photometry. The computed optical density was digitalized and evaluated with an image analysis system. The results indicate a significantly higher amount of M2-PK in malignant tumours. In the adenocarcinomas of the mammary gland, the content of the M2-PK increased parallel with malignancy (p less than 0.01; r = 0.743). The M2-PK can serve as an indicator of the grade of malignancy in mammary tumours of the rat.

Animals↗
PubMed1991

Detection of charges and their distribution on dialysis membranes with cationic/anionic dyes using confocal laser scanning microscopy.

Methods for the detection of positive or negative charges on the surface of biomaterials/membranes and inside a membrane are important for the characterisation of such materials. We tested different dyes and optimized staining procedures. Under standardized conditions negatively charged membranes were stained with cationic triarylmethane compounds such as crystal violet and positively charged membranes with the anionic anthraquinone dye anthralan blue B. There was no staining of uncharged cellulose membranes. The applicability of these methods was demonstrated on membranes coated to varying degrees with charged compounds such as heparin, these changes in charge being detectible quantitatively by photometry. The distribution of charges inside a membrane was detected by optical sectioning across the stained (FITC labelled poly-L-lysine) membrane using confocal laser scanning microscopy (LSM). LSM offers a completely new application possibility in biomaterial and biocompatibility research.

Biocompatible Materials↗
PubMed1992

New enzymatic method with tryptophanase for determining potassium in serum.

We established a simple and rapid enzymatic method for measuring potassium ion in serum by using tryptophanase (EC 4.1.99.1) purified from Escherichia coli K12 strain (E. coli K12 IFO 3301). The presence of pyridoxal 5-phosphate promotes this enzymatic reaction, and potassium and (or) ammonium ions further accelerate it, with ammonium and potassium ions providing equivalent acceleration. We eliminated endogenous ammonium ion by using glutamate dehydrogenase (GLDH; EC 1.4.1.4), then produced ammonium ion in the presence of tryptophanase, tryptophan, and pyridoxal 5-phosphate. The concentration of formed ammonium ion, which was proportional to that of potassium ion in sample, was determined by adding GLDH to produce NADP+ in the presence of 2-oxoglutarate and NADPH; we then read the change of absorbance at 340 nm. The standard curve was linear for potassium ion concentrations up to 7.00 mmol/L. The within-assay variation (CV) was 0.89% at 5.51 mmol/L and 1.32% at 3.37 mmol/L. The day-to-day CVs were 0.99% at 6.85 mmol/L and 1.71% at 3.52 mmol/L. Analytical recoveries ranged from 98.7% to 108.9%. The correlation coefficient between values obtained with this enzymatic assay (y) and by flame photometry (x) was 0.995: y = 0.984x + 0.091 mmol/L (Sy.x = 0.105, n = 100). The presence of hemoglobin, bilirubin, or other cations little affects this system.

Ammonia↗
PubMed1991

A method for determining the total magnesium, calcium, sodium and potassium contents of human platelets.

Platelet levels of magnesium, calcium, sodium and potassium may provide a better index of intracellular cations or total body ion status than serum, erythrocyte or leukocyte cation concentrations. A method is described for the determination of the total magnesium, calcium, sodium and potassium contents of human platelets. The method involves platelet isolation, repeated washing, lysis and measurement of the ions in the lysate. Magnesium and calcium were determined by atomic absorption spectroscopy and sodium and potassium by flame photometry. Platelet total potassium, magnesium, calcium and sodium were 4.5 +/- 1.5, 2.3 +/- 0.6, 1.8 +/- 0.5, 1.5 +/- 0.6 mumol/1 x 10(8) cells, respectively (means +/- SD). The method is simple, repeatable and accurate.

Adult↗
PubMed1991

[Damage to the corneal endothelium caused by radial keratotomy].

In our experimental study on 53 rabbits we compared the amount of corneal endothelial damage caused by radial keratotomy (RK) referred to (1) the number of incisions (4, 8, or 16), (2) the postoperative interval (0 h, 48 h) and (3) the direction of the incision [centripetal (cp), centrifugal (cf)]. The endothelial damage was quantified by means of the Janus green photometry technique. Morphological changes were evaluated by scanning electron microscopy (SEM). Depending on the group examined, we found endothelial damage extending over 3-7% of an analysed surface of 64 mm2. One perforation caused endothelial damage of up to 17% of the surface examined. Increasing the number of incisions from 4 to 8 or 16 resulted in a statistically significant increase in the amount of endothelial damage (4.2%, 5.1%, 5.8%; P less than 0.05). At 0 h it was significantly higher than after 48 h (5.5%, 4.6%; P less than 0.05). The direction of the incision had no statistically significant influence in our study (zp: 5.2%, zf: 4.9%). The morphological changes in the rabbit corneal endothelium examined directly after the RK procedure were ruptures in the cell membranes, loss of cells, and posterior corneal protrusions beneath the incisions. After 48 h, we found fewer damaged cells and no denuded Descemet's membranes, but larger polymorphy of the cells and a numerical increase in the microvilli of the cells surrounding the damaged cells. Our results support the crucial argument against RK: the alteration and destabilization of healthy corneal tissue up to the endothelium.

Animals↗
PubMedDate not supplied

[Non-visual effects of light mediated via the optical route: review of the literature and implications for occupational medicine].

Artificial light which now plays an essential role in industrialized society differs from natural light both in intensity which is usually lower, and in spectrum, which is usually smaller. It is now a well-known fact that the human body is able to use luminous stimulation for aims other than sight; the pineal gland, though no longer directly sensitive to light as in lower animals, is nevertheless the fulcrum of a complex neuro-endocrine system which makes an interaction between light and the human body possible by means of the production of a number of substances of which melatonin is the most widely investigated. Melatonin is secreted at a circadian rhythm characterized by high nocturnal seric levels and low diurnal levels. This secretion appears to be correlated not only with the intensity of the light but also with its spectrum and time exposure. Even though the function of melatonin is still not fully understood, it seems possible to assign a mainly modulatory role to the pineal gland and melatonin. On the basis of studies performed on the pituitary-gonadal and/or hypothalamic axis and the reproductive system in animals, melatonin would appear to affect some endocrine functions (i.e., puberty) in man, too. Changes in melatonin secretion have been found in psychiatric illness, especially in cyclical affective disorders. Melatonin seems to be involved in stress-associated mechanisms, probably with an agonistic role, and also in carcinogenesis, where it seems to play a role in the growth of several tumors. Melatonin also affects both tumoral and cellular immune responses. Lastly, melatonin may be able to reduce the symptoms of the Jet Lag Syndrome. The consequences that prolonged and marked reduction in daylight exposure for occupational reasons could have on operators, especially young people, therefore constitute an interesting subject for occupational health; environmental photometry at the work-place, if adequately performed, could make a useful contribution to the development of this field of research.

Adolescent↗
PubMed1991

Test systems with synthetic peptide substrates in haemostaseology.

Since the early seventies, synthetic peptide substrates have been used in haemostaseology, enabling the introduction of photometry in coagulation analysis. Synthetic peptide substrates are short peptides (3-5 amino acid residues), with a chromogenic group coupled to the C-terminal end by an amide bond. The chromogenic group may be relatively specifically removed by proteases, and measured photometrically. By using the special properties of the many available substrates, test systems have been developed for procoagulant clotting factors, fibrinolytic factors, inhibitors of both systems and also for global tests of plasmatic coagulation. These tests can be performed manually or on automated analytical systems with high specificity, sensitivity and accuracy. The analytical advantages and new possibilities of the tests with chromogenic substrates have, in recent years, decisively stimulated not only haemostaseological basic research, but also clinical investigation and routine. Today, inhibitors of plasma coagulation (e.g. antithrombin III, protein C, C1-esterase inhibitor) as well as fibrinolytic parameters (e.g. tissue plasminogen activator, plasminogen activator inhibitor, alpha 2-antiplasmin) are nearly exclusively determined with chromogenic substrates. Further development will constitute the application of chromogenic substrates to "dry chemistry" methods.

Amino Acid Sequence↗
PubMed1991

[The osmoregulatory and natriuretic functions of the kidneys in the early stages of the evolution of hypertension].

Overall 78 men were examined. Of these, 30 presented with borderline arterial hypertension (BAH), 30 with stage I essential hypertension (EH), and 18 healthy subjects served as control. To assess osmoregulating and natriuretic renal functions, water and water plus salt were administered (at a rate of 22 ml water or isotonic sodium chloride per kg bw). Use was made of classic approaches in this case, with the determination of K+, Na+ excretion, blood plasma and urine osmolarity, calculation of the concentration index, clearance of osmotic-active substances and free water, total reabsorption of Na in the distal parts of nephron and intensity of that process. Besides, flame photometry was employed to measure blood K+, Na+ concentration and RIA to examine plasma renin activity. The data obtained indicate the heterogeneity of the patients with BAH and stage I EN according to the response to water and water and salt administration. Approximately 1/3 of the patients showed a tendency towards water retention in the body as well, which is common to patients with the volume-dependent form of arterial hypertension. In that case the compensatory potentialities of modulating renin-angiotensin system activity were preserved.

Adult↗
PubMed1991

Electrolytic exchange in organism under the conditions of vibration. Experimental studies.

The study deals with a wide spectrum of indices of the electrolytic metabolism--sodium, potassium, calcium, chlorides, magnesium, iron, copper, zinc, cobalt and manganese--in blood, organs and tissues under the conditions of experimental chronic exposure of whole-body vibration frequency of 50 and 150 Hz and velocity of 85 mm.s-1 during a three months experiment (3 h daily) Reference methods were used for the determination of the indices--atom absorption spectrophotometry (variants with flame and without flame), coulometric chlorine titrator, flame photometry, etc. The indices were examined three times (1, 2 and 3rd months). Statistic analysis of the data showed significant changes in the number and the values of the indices and their character (increase or decrease) in comparison with the control values. The indices modifications occur early (at the end of the first month) and they proceed till the end of the experiment (till the end of the 3rd month) during the exposure to both frequencies, but are strongly expressed in the case of high frequency vibrations. The disorders in electrolytic metabolism established in the experiment testify that people exposed to vibrations are likely to suffer analogical changes and develop other pathologies--diseases of cardiovascular system, of blood and haematopoietic organs, etc. as well as an increase of specific disorders in connection with vibration exposure.

Animals↗