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PubMed1982

[Specific stress of intensive therapy: its analysis and suggestions for changes].

Proceeding from studies which make the environment of an intensive care unit responsible for psychopathological disturbances in thoracic patients, we made investigations on an operative intensive care unit concerning its influence on the psychical state of surgical patients. For this purpose photometry and noise measurements were made at the patient's bedside; additionally the environment of a ventilated patient was recorded continuously by means of a cine-camera. The results we obtained from noise measurements showed that all patients were affected with both sensorial monotony and sensorial overstimulation. Overstimulation results from sudden and unexpected noise (for example due to emergency admissions) on an intensive care unit. The analysis of the illumination intensity showed a day and night turn; that means, the patient was able to distinguish between daytime and nighttime but due to missing bearings no further temporal orientation was possible. The filmings demonstrated that there were numerous contacts between the patient and his environment which, however, did not last longer than 105 s on an average. These findings refer to the problem of the patient's social isolation; others show the loss of sleeping and resting stages. So the "resting stages", that means stages without visible contact, last between 1-3 min. In the light of the results, psychopathological disturbances in the patients of this intensive care unit are connected with the situational conditions of the unit. Suggestions concerning the removal of situational load-factors are deducible from these findings.

Adolescent↗
PubMedDate not supplied

Flash detection of anti-H-2 antibodies using chemiluminescence, without complement.

Within the first minute following their exposure to a specific anti-H-2 serum and in the absence of complement, murine spleen cells generate a chemiluminescence phenomenon which is precisely measurable by photometry in the presence of luminol. The reaction lasts approximately 10 to 20 minutes, it also generated by bone marrow and, although weakly, by peritoneal cells. In contrast, thymus cells remain totally unresponsive. The striking inhibition of the phenomenon in the presence of superoxide dismutase confirmed that it is indeed due to O2(-). This rapid, simple, inexpensive, extremely sensitive and reproducible technique offers the advantage of focusing on the histocompatibility antigens borne by monocytes, macrophages and granulocytes. Lastly, this O2(-) production triggered by anti-H-2 antibodies should be kept in mind when discussing the mechanism of vascular damage in allograft rejection.

Animals↗
PubMed1981

Response monitoring and action limits: use of ADC numbers in understanding the operational characteristics of the Beckman ASTRA chemistry system.

The Beckman ASTRA is a microprocessor-controlled multichannel chemistry analyzer. The output of each module is available to the operator as analog-to-digital conversion (ADC) numbers, which we record during each calibration (Response Monitoring). After so studying three instruments for a total of 33 months, we have established limits for Calibrator ADC numbers that indicate possible operator action (Action Limits). These Action Limits are tighter than the microprocessor's programmed limits, and alert the operator to short- and long-term drift. These tighter limits warn of (a) impending failure of the instrument to calibrate or (b) possible inaccuracies in results for patients. We have instituted changes in preventive maintenance based on our studies of each module's operational characteristics, and have replaced electrodes that failed to meet our Response Monitoring specifications. Response Monitoring and Action Limits based upon ADC numbers have significantly enhanced our understanding of the ASTRA system and thus improved its operational efficiency and analytical reliability. Estimates of precision and accuracy (true value) were satisfactory in comparison to our prior single-channel continuous-flow and flame photometry analytical measurement systems.

Autoanalysis↗
PubMed1981

Selectively aspirated pure pancreatic secretion. Viscosity, trypsin activity, protein concentration and lactoferrin content of pancreatic juice in chronic pancreatitis.

The viscosity, trypsin activity, protein concentration and lactoferrin concentration in selectively aspirated, pure pancreatic secretion uncontaminated by bile, were determined in 46 patients with chronic pancreatitis and compared with the values obtained in 39 control subjects. The viscosity was measured using a modified capillary viscosimeter, the trypsin activity and the protein concentration using photometry, and the concentration of lactoferrin employing a new standard. It was found that in chronic pancreatitis, viscosity, trypsin activity and lactoferrin concentration was also found to be increased, but the differences were not significant. The results of this examination support the hypothesis that precipitation of protein-containing material in the pancreatic ducts, delayed outflow of secretion and premature activation of trypsin are pathogenically important factors in chronic pancreatitis.

Adult↗
PubMed1980

Method for determination of hydrogen peroxide, with its application illustrated by glucose assay.

We describe a simple colorimetric method for determining micromolar quantities of hydrogen peroxide, based on the oxidation of iodide in the presence of ammonium molybdate and photometry of the resulting blue starch-iodine complex. Color development is linearly dependent on analyte concentration, but only slightly time dependent, and the color of the complex formed is stable for several hours. In the range of wavelengths that may be used (570 to 630 nm), lack of interference from other biological compounds makes this method seem suitable for routine analyses. As one illustrative application of the method we quantitated glucose by measuring hydrogen peroxide produced from it by glucose oxidase catalysis. This method of quantitating glucose is more than five times as sensitive as the commonly used dianisidine method. With the appropriate hydrogen peroxide-producing oxidases, this method may be used to directly measure amino acids, purines, uric acid, xanthine, and hypoxanthine.

Colorimetry↗
PubMed1981

Determination of sodium with ion-selective electrodes.

The advent of ion-selective electrodes made possible the potentiometry of sodium in serum and plasma. These methods were based on dilution of serum, as done in flame photometry, and the results were identical. Analysis of whole blood precludes dilution and so "direct" potentiometry was developed. Results by this technique are variable but tend to compensate for the spurious hyponatremias found by the "indirect" dilution methods due to displacement of volume by lipids and protein. However, there is no unambiguous theoretical basis on which to choose between the various direct ion-selective-electrode techniques and instruments. As an alternative, I propose use of current indirect methods, with numerical correction for the shift in normal sodium values in the presence of abnormal lipid and (or) protein. A table was constructed for making such corrections.

Blood Proteins↗
PubMed1981

[Erythrocyte membrane permeability of sodium in different types of chronic experimental hypertension].

The permeability of the red blood cell membrane for sodium in rats with spontaneous genetic hypertension, in rats with renovascular and DOCA-salt-induced hypertension as well as the effect of high salt diet on the permeability were studied using the flame photometry method. The increase permeability of the red blood cells in the rats with spontaneous genetic hypertension was observed, while no changes occurred in the cases of DOCA-induced and renovascular hypertension. Salt load as well as deoxycorticosterone administration had no effect on the permeability of the red blood cell membrane.

Animals↗
PubMed1980

Stable reagents and a suitable routine procedure for the cystinuria test.

A simplification of the borohydride-cyanonitrosylferrate (nitroprusside) test for cystine in urine is described. The borohydride reagent is stabilised by cooling and by using pure components. Octanol-1 is used to reduce foaming. The cyanonitrosylferrate reagent is stabilised by sulphite and by storage at -80 degrees C. Compared with previous methods, it is possible to use higher (more than 4 times) dilutions of urine. An aqueous cystine solution may be used as a standard for visual evaluation; for the previous methods there is no well defined material for standardisation. The described procedure is intended for visual evaluation; the method is also suitable for quantitation by photometry.

Borohydrides↗
PubMed1980

[Spectrophotometric method of determining aminoglycoside antibiotics].

Azo-derivatives of chromotropic acid and azo-dyes of the stilbene series were studies as possible reagents for photometric determination of aminoglycoside antibiotics (AB) in biological materials. The complex of Pr3+ with stilbazochrome-P (Sch-P) proved to be the best precipitant of AB. P (Sch-P) with Pr3+ and AB in acetate and citrate buffer-solutions formed a precipitate with AB:Pr:Sch-P = 1 : 1 : 3. Most of the metallic cations and anions did not prevent formation of the precipitate in the citrate buffer. A procedure for determination of 0.01--100 micrograms of AB in biological materials was developed with the use of Sch-P. The procedure is based on separation of the AB:Pr:Sch-P precipitate and photometry of the sypernatant solution at 560 nm.

Aminoglycosides↗
PubMed1980

[Effect of methionine and vitamins B12 and B15 on the content and distribution of proteins, glycogen and lipids in the hepatic lobules of chickens].

The effect of methionine (10 g/kg of food) added in combination with vitamin B12 (25 mkg/kg of food) and vitamin B15 (20 mg/kg of body weight) on the content of glycogen, protein and lipids in the chicken hepatic lobule has been studied on the background of a disbalanced diet. To the disbalanced ration 5% of rancid technical oil was added. The preparations were subjected to photometry in the scanning integrating microscope CIM-1. Comparing with the control, the disbalanced diet decreases the content of glycogen in the liver by 7%, protein--by 27% and increases that of lipids by 32%. Methionine added in combination with vitamins B12 and B15 normalizes the hepatic histochemical indices. Glycogen is firstly accumulated along the lobular periphery and it is this part of glycogen that is mostly subjected to both hepatotrophic and normalizing effects. Lipids also accumulate from the periphery towards the lobular center. The process of normalization of the lipid content is evidently directed from the center towards the periphery. In the central lobular part the protein content is increasing, the process being more pronounced when methionine is added in combination with vitamin B12 than with vitamin B15.

Animal Feed↗
PubMed1980

[Effect of odiphalin and difril on catecholamine concentration in adrenergic nerve fibers of different rat organs].

The histochemical method of Axelsson coupled with photometry was used to study variations in the content of biogenic amines in different rat organs (myocardium, vas deferens, mesenteric vessels, iris, atrial and ventricular heart valve) under the effect of odiphalin and difril. The results obtained indicate that the organs with direct, indirect and mixed innervation differ in the pattern of response to the pharmacological agents administered. Venous vessels proved to be the most sensitive to the action of odiphalin and difril. The data obtained warrant a conclusion about the heterogeneity of adrenergic nerves in organs and tissues.

Adrenergic Fibers↗
PubMed1995

[The time required topical carbonic anhydrase inhibitor (MK-507) to take effect on intraocular pressure of normal human eyes].

The effective time course of a topical carbonic anhydrase inhibitor, MK-507, on intraocular pressure (IOP) was studied in 6 normal volunteers. As a baseline study, IOP was determined and aqueous protein concentration was determined by laser flare photometry every half hour for 5 hours with the instillation of a placebo. Then, an examination with the same time course was performed on the same subjects with the instillation of 1% MK-507 or oral administration of acetazolamide at a dose of 250 mg. MK-507 lowered IOP 30 minutes after the instillation, and showed a significant reduction of IOP at 1 hour. Aqueous protein concentration increased significantly 30 minutes after the MK-507 instillation. Acetazolamide lowered IOP 30 minutes after the administration, and showed a significant reduction of IOP at one hour. Aqueous protein concentration increased significantly one hour after the acetazolamide administration. Corneal thickness, anterior chamber depth, anterior chamber volume, and serum protein concentration were not significantly changed by the drug treatment. These results suggest that the inhibition of aqueous humor production causes the rapid reduction of IOP seen in the use of MK-507 as well as acetazolamide.

Administration, Topical↗
PubMed1995

Accommodation to monochromatic and white-light targets.

PURPOSE: The objective of the current study was to compare accommodation to targets illuminated with monochromatic light from different regions of the visible spectrum with accommodation to white-light targets. METHODS: One of 10 marrow-band interference filters (430, 450, 470, 500, 530, 550, 570, 590, 630, and 670 nm) was used to produce monochromatic light from a tungsten-halogen source to illuminate a Maltese cross-target in Maxwellian view. Luminance of each monochromatic light was matched by minimum border photometry against a standard white light (3000 K) that was maintained at 200 cd/m2. Chromatic difference of focus of the eye was minimized for all monochromatic targets by the use of an achromatizing lens. A white-light target also was used, and the subject's eye was achromatized or the eye had normal chromatic aberration. The target was moved sinusoidally toward and away from the eye at a temporal frequency of 0.2 Hz over a 1 D amplitude (peak to peak). Accommodation was monitored continuously by an infrared recording optometer, and responses were Fourier analyzed to obtain gain and phase lag at the temporal frequency of stimulation. RESULTS: Accommodative gain was highest and phase lag was smallest when the target was illuminated by white light in the presence of normal chromatic aberration. The achromatized white-light gain of accommodation was statistically similar to the gain for monochromatic targets, indicating that the presence of chromatic aberration facilitates accommodation. Significant intersubject variability was present in the accommodative tracking ability to monochromatic targets. CONCLUSIONS: Accommodation to monochromatic targets is not as accurate as accommodation to a white-light target, and this effect is related to the presence of ocular longitudinal chromatic aberration for the white-light target.

Accommodation, Ocular↗
PubMed1995

Measurement of methemoglobin in neonatal samples containing fetal hemoglobin.

Because of the potential for methemoglobinemia during nitric oxide therapy in newborns, methods are needed to accurately quantify methemoglobin (MetHb) in the presence of the high concentrations of fetal hemoglobin (Hb F), bilirubin, and lipids seen in these patients. Spectral differences between fetal and adult Hbs invalidate assumptions of conventional multiwavelength Hb photometry, so we evaluated an "overdetermined" system (Ciba-Corning Model 270), in which absorbances at seven wavelengths are measured to quantify four Hb derivatives. Adult and umbilical cord blood (Hb F 96%) samples were prepared to contain known MetHb fractions. Measured MetHb was linear in cord blood to > or = 15% MetHb. Within-run precision (CV) was < 2.2% (n = 10) at each of seven MetHb fractions between 5% and 100%. Measured (y) and expected (x) MetHb fractions in cord blood were in good agreement (y = 1.0200x + 0.100, Sylx = 0). Added bilibrubin (200 mg/L serum) and lipid (30 g/L) did not interfere. No significant differences were seen for adult and cord blood samples with identical MetHb fractions (P = 0.72), whereas a significant difference was noted with an exactly determined system (P = 0.0033). At clinically relevant MetHb fractions (< 15%), a trend towards increased values in cord blood was noted with an exactly determined system (y = 1.0520x + 0.7600). We conclude that this overdetermined system measures MetHb accurately in samples from patients with large concentrations of Hb F.

Adult↗
PubMedDate not supplied

The distribution of nucleic acid chromophores at cellulose-water interfaces. 2. Thermodynamic parameters.

A Previous theoretical' model (O. L. Hörer, Adriana Grigorescu Rev. roum. Virol, 1992, 43, 33) allowed us to appraise the "absorbed" mole fraction chi of chromophores, using the Multiple Light Scattering Enhanced Absorbance (MLSEA) bichromatic photometry. In the present paper the data were used to express thermodynamic parameters, based on the Gibbs free enthalpy G. In terms of the ion exchange capacity of several chromatography papers used in the former paper, the RNA chromophore distribution at the interface was correlated with thermodynamic parameter, showing characteristic patterns. The thermally denatured DNA was studied in the same way and a new insight of the helix-coil transition in terms of ionic strength was achieved.

Adsorption↗
PubMed1995

Sweat sodium and chloride analysis using BM/Hitachi 911 ion-selective electrodes.

The suitability of Hitachi 911 ion-selective electrodes to analyse neat sweat samples for sodium and chloride was investigated. Sweat samples obtained using the Gibson and Cooke method were analysed by flame photometry for sodium and coulometry for chloride. Specimens obtained by the Wescor Macroduct collection procedure were analysed by ion-specific electrodes. No significant differences between sodium and chloride results were found between the two different collection methods and analysis procedures. Analysis of neat sweat can reduce errors in sweat analysis by eliminating extraction and dilution stages. Errors could occur with use of a serum compensator in the calibration of ion-selective electrodes.

Chlorides↗
PubMed1995

[Clinical biochemistry and laboratory medicine in the 21st century].

The author gives an outline of the assumed development of clinical biochemical examinations in future decades based on the development during the past 40 years. The development of biochemical analyzers will probably mean more perfect robotization; the increase in capacity (number of tests performed per hour) probably will not result from more rapid individual analyses (the rate of 900 tests/hour is probably optimal) but the capacity will be increased by doubling and trebling of critical elements (photometry or technique of measurements, pipetting etc.). Probably the volume of blood samples will not be reduces (to less than 1-2 microliters); however, amplification techniques will be used far more (as at present the polymerase chain reaction and others (for replication of cellular substances such as DNA). There will be a shift and greater use of "in vivo" techniques such as magnetic resonance spectroscopy and examinations using biosensors (because of the possibility and in particular expedience of examining some analytes continuously). The examined spectrum will be extended by further substances (in particular those with a short-term existence such as e.g. cytokines, selectins, adhesive molecules etc.; manifestations of circadian dynamics will be followed up much more e.g. in tumours, or chronopharmacokinetics of some drugs. A great development may be foreseen in the sphere of the use of computer technique for evaluation and communication of laboratory data and other data on the patient. For consultations global (or at least regional) computer networks will be much more widely used.

Chemistry, Clinical↗
PubMed1995

Are reference intervals for carboxyhemoglobin appropriate? A survey of Boston area laboratories.

CO is a leading cause of poisoning deaths in the US today. Treating physicians use the carboxyhemoglobin (COHb) % saturation to guide the diagnosis and treatment of CO intoxication. We conducted a telephone survey of hospitals and laboratories in the Boston area, focusing on methodology for COHb determination and accompanying COHb reference intervals. Among 130 facilities, 23 (18%) provide COHb analysis. All facilities that perform the COHb test utilize dedicated multiwave-length photometry. Reference intervals for COHb varied widely among facilities. Eight of 21 (38%) facilities give unacceptably high "normal intervals" for nonsmokers when compared with values available in the literature. Thirteen of 20 (65%) use reference intervals for smokers that are too low, and 3 of 20 (15%) use values that are too high. These reference values provided by the testing facilities may be misleading to the ordering physicians unfamiliar with background COHb saturations. This may lead to misdiagnoses, false reassurances, and perhaps less aggressive treatment than might be warranted. The results of this study argue for wider adoption of COHb reference intervals supported by the current literature.

Boston↗