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At least 109 records · Page 6Linked to original sources
PubMed1983

Study of urinary specific gravity by reagent strip method.

A newly developed reagent strip method for determination of urinary specific gravity is described. This reagent strip (Chemical S.G., Ames Co.) contains polyelectrolyte which is sensitive to the cation in solution. The urinary specific gravity is mainly decided by cation (Na+ and K+) concentrations in urine. As a result, the reagent strip gave measurements that corresponded to those measured by refractometry and gravimetry of NaC1 solution. Urea and glucose gave increased values by the refractometer, whereas the reagent strip did not cause changes. The values of urinary specific gravity obtained from reagent strip showed not only good correlations (r = 0.79-0.93) with the refractometry and gravimetry but also urinary osmolarity. This reagent strip method proved to be a most convenient tool for routine urinalysis because of the good reproducibility and accuracy considering its easy handling.

Contrast Media↗
PubMedDate not supplied

[Changes in clinical refraction in future pilots during the course of training].

Changes in clinical refraction parameters were followed up in 343 students of school of pilots in the town of Burguruslan in the course of vocational training. Skiascopy and laser refractometry methods were used. Dynamic follow-up of clinical refraction showed its increase in 24.3% of the examinees both with emmetropia and hypertropia or myopia. The most noticeable increase of refraction was observed during the first two years of training, which may be explained by intensive exercise of the eyes because of theoretical studies and flights. The results evidence practical advantages of laser refractometry in comparison with skiascopy.

Aerospace Medicine↗
PubMed1993

The effects of diaper brands, urine volume, and time on specific gravity measurement.

Nurses use urine specific gravity to assess fluid volume status in pediatric patients. Specific gravity of five leading brands of disposable diapers was measured to determine the effects of diaper brand, urine volume, time elapsed, and method of specific gravity measurement comparing the two methods of refractometry and N-Multistix SG (Ames Division, Miles Inc., Elkhart, IN). Immediately after a baby voided 20 mL of urine into any disposable diaper, the specific gravity by refractometer accurately compared with the control standard. Measurement accuracy by N-Multistix SG was only assured if Pampers (Procter & Gamble, Cincinnati, OH) were used. However, both methods were inaccurate at 4 hours with 20 mL of urine. Immediately after a baby voided 40 mL of urine into any disposable diaper, both methods were accurate when compared with the control. At 4 hours, only Pampers and Chux (Procter & Gamble, Cincinnati, OH) were accurate by refractometry, and Pampers alone was accurate by N-Multistix SG.

Humans↗
PubMed1998

Accommodation amplitude after lens refilling with injectable silicone by sealing the capsule with a plug in primates.

OBJECTIVE: To restore accommodation in primate eyes by refilling the lens capsule with injectable silicone compounds. MATERIALS AND METHODS: Eight eyes of 8 monkeys (Macaca fascicularis) were treated by the lens refilling procedure. To prevent leakage of the injected liquid silicone before it polymerized in the capsule in vivo, a silicone plug for sealing the capsular opening was developed. After endocapsular phacoemulsification following an upper minicircular capsulorhexis, the plug was introduced into the capsulorhexis opening. A silicone mixture was injected into the capsular bag through the delivery tube of the plug. Automated refractometry was performed 1 week and 3 months after surgery. Accommodation amplitude was determined as the difference between the refractions before and 1 hour after topical application of 4% pilocarpine chloride. RESULTS: Five of 8 eyes could be refilled. In 4 of 5 eyes, refraction could be measured. Accommodation amplitude ranged from 1.0 to 4.5 diopters, with a mean of 2.3 +/- 1.3 diopters (8.0 +/- 2.0 preoperative values). At 3-month examination, thick posterior capsule opacification precluded refractometry in all eyes. CONCLUSIONS: The lens refilling procedure with the use of a silicone plug for sealing the capsular opening was feasible in primate eyes. The accommodation amplitude attained was a small fraction of the value before surgery. This may result from the loss of so-called intracapsular accommodation, ie, active participation of lens fiber cells in accommodation. However, since the obtained accommodation may be sufficient for near vision after cataract surgery, this lens refilling procedure warrants further study. Elucidation of the mechanism of intracapsular accommodation may also be necessary.

Accommodation, Ocular↗
PubMed1983

Concentration and composition of plasma proteins in wild mammals.

Total protein concentrations from a variety of wild mammalian species were measured by the Lowry and Biuret techniques and compared with results obtained or derived by refractometry. Values obtained with the Lowry method were the highest and certain derived refractometry results, the lowest. It is suggested that the Biuret method provides the most acceptable values but that care should be exercised in using the correct standard. The percentage composition of plasma from 22 species of wild mammals is also presented and the observations discussed with relation to methodology and A/G ratio.

Animal Population Groups↗
PubMed1982

Thermodynamic characterization of hog kidney D-amino acid oxidase apoenzyme in concentrated guanidine hydrochloride solution. Preferential interaction with the solvent components and the molecular weight of the monomeric unit.

This paper describes the physical characterization of the monomeric unit of hog kidney D-amino acid oxidase apoenzyme in 6 M guanidine hydrochloride (GuHCl) solution by means of differential refractometry, densimetry, light scattering, equilibrium sedimentation, and high-speed gel filtration chromatography. In 6 M GuHCl solution, the oxidase interacts preferentially with GuHCl: the values of the preferential interaction parameter are 0.11 +/- 0.03 (S.D.) g/g of protein by densimetry and 0.14 +/- 0.04 g/g of protein by refractometry. The volume change, delta V, of the oxidase on transfer from the native to the denatured state is -350 ml/mol. The molecular weight of the monomeric apoenzyme is 39,600 +/- 1,700 by light scattering and 38,000 +/- 1,200 by high-speed equilibrium sedimentation. The values of the molecular weight estimated by the empirical methods, i.e., sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis and high-speed gel filtration chromatography in 6 M GuHCl, agree well with those obtained by the thermodynamic methods mentioned above. These results confirm definitely that the complex of the apoenzyme with SDS normally behaves in the same manner as those of standard proteins in SDS-gel electrophoresis. This is also supported in this study by the analysis of the electrophoretic data at several gel concentrations by Ferguson plots. The molecular weight of quasi-D-amino acid oxidase apoenzyme was also examined by the empirical methods.

Animals↗
PubMed1990

Subunit constitution of carbonic anhydrase from Chlamydomonas reinhardtii.

Carbonic anhydrase purified from the cell surface of Chlamydomonas reinhardtii was inactivated by treatment with dithiothreitol. This treatment caused dissociation of the holoenzyme into 35-kDa (A) and 4-kDa (B) subunits as revealed by SDS/PAGE. The 35-kDa subunit was further separated into two components A1 (35 kDa) and A2 (36.5 kDa) by SDS/PAGE using a gradient gel. These two components have the same amino acid sequence up to at least the 10th amino acid from the N-terminus. The molecular masses were estimated at 76 kDa and 35 kDa for the holoenzyme and the large subunit, respectively, and the molar ratio of the former to the latter at 1:2, by using the techniques of low-angle laser light-scattering photometry and precision differential refractometry combined with gel-filtration HPLC. The molar ratio of the 35-kDa/4-kDa subunits was estimated at 1:1 the gel-filtration HPLC monitored with precision differential refractometry. Atomic-absorption spectrophotometry revealed that the holoenzyme contains two atoms of zinc. These results suggest that the holoenzyme is a heterotetramer composed of two large subunits (A1 and A2) and two small subunits (B).

Amino Acid Sequence↗
PubMedDate not supplied

[Analysis of solutions for parenteral use under field conditions].

Methods for determination of relative density, osmolarity, then refractometry, polarymetry and conductometry as simple methods suitable for work under field conditions have been applied for the quality control of the following solutions for infusion and injections: glucose, mannitol, sodium chloride, sodium hydrogencarbonate, magnesium sulphate and potassium chloride. The results obtained in the analysis of preparations have shown the advantage of refractometry.

Infusions, Parenteral↗
PubMed1984

Influence of edge sharpness on the accommodation of the human eye.

Using a subjective method of laser refractometry, the accommodation behavior of six subjects toward real targets with various degrees of blur, dependent on the viewing distance, were investigated monocularly and binocularly. Despite the sharpness of the target, the nominal value is only reached incompletely with a lag of accommodation, because accommodation tends to be as minimal as possible. Increasing blurring leads to a drift of accommodation towards the resting position of accommodation. The resulting underaccommodation causes further physiological blurring of the retinal image of the targets. The approach of the targets to the resting position of accommodation leads to a higher precision of adjustment and less drift. Subjective components (accommodative laziness, cognitive demand) influence the accommodation and increase the phenomenons discovered.

Accommodation, Ocular↗
PubMed1991

Active and monomeric human red cell glucose transporter after high performance molecular-sieve chromatography in the presence of octyl glucoside and phosphatidylserine or phosphatidylcholine.

The human red cell glucose transporter (Glut 1) was purified by ion-exchange chromatography in the presence of octyl glucoside. The state of association of the protein was studied, and the transport activity was determined after exchange of copurified membrane lipids for phosphatidylserine (PS) or phosphatidylcholine (PC). The purpose was to analyze the Glut 1 preparation for homogeneity and activity prior to attempts at crystallization. Analyses by high performance molecular-sieve chromatography showed that the Glut 1 was monomeric immediately after the ion-exchange purification: the Mr of the Glut 1 polypeptide was estimated to be 49,000 +/- 6000 by TSKgel G3000SW chromatography monitored by low-angle laser light-scattering photometry, differential refractometry and UV photometry. This required determination of the absorption coefficient of the Glut 1, which was measured to be 1.13 +/- 0.03 ml mg-1 cm-1 at 280 nm, referring to the polypeptide concentration. The Mr value is consistent with the cDNA-deduced Mr 54,117 of the very similar HepG2 glucose transporter polypeptide. At 2 degrees C, pH 7 and an ionic strength of 0.06 M, the Glut 1 associated gradually during three days to form oligomers. These formed much more rapidly at room temperature or at high ionic strength. Freshly prepared Glut 1 retained high activity after separation from membrane lipids on a TSKgel G3000SW column in the presence of 40 mM octyl glucoside and 1 mM PS or PC. In contrast, most of the activity was lost when the membrane lipids were separated from the protein in the absence of eluent lipids. The presence of a phospholipid was thus essential for retention of high activity of the Glut 1 in octyl glucoside and PC was nearly as effective as PS.

Chromatography, Gel↗
PubMed1991

Determination of cholesterol and cortisone absorption in polyurethane. I. Methodology using size-exclusion chromatography and dual detection.

A size-exclusion chromatographic method is described for measuring the absorption of the steroid-based lipids cholesterol and cortisone into Pellethane 2363, a polyurethane used in biomedical implants. The method uses refractometry and ultraviolet diode-array detection, with tetrahydrofuran as the mobile phase. Using an injection volume of 150 microliters, the lower limit of accurate measurement for cholesterol (refractive index detection) was 6 micrograms/ml with a lower limit of detection, based on a 2:1 signal-to-noise ratio, of 0.15 micrograms (1 microgram/ml). For cortisone (ultraviolet detection), the lower accurate limit was 0.6 micrograms/ml with a lower limit of 0.015 micrograms (0.1 micrograms/ml). The results show that after 44 h, 2037 micrograms/g cholesterol and 3131 micrograms/g cortisone were absorbed by the polyurethane. The method eliminates extensive sample manipulation and is sensitive to low levels of lipid in the presence of a high-molecular-mass synthetic polymer.

Absorption↗
PubMed2000

Direct determination of amino acids and carbohydrates by high-performance capillary electrophoresis with refractometric detection.

This is an initial report to propose a novel approach in high-performance capillary electrophoresis (HPCE) for the direct detection of compounds without natural absorbance in the UV and visible spectral range, such as amino acids and carbohydrates. A refractometry detector with the 2 nl cell (Applied Systems, Minsk, Belarus) was employed to identify amino acids and carbohydrates without derivatization. The first results are provided on separation of seven free amino acids in the phosphate running buffer and three free carbohydrates in the borate-sodium dodecyl sulfate running buffer and detection by refractometer. Fused capillaries of 50 or 75 microm internal diameter and separation voltage (10-23 kV) were applied. Detection limits ranged typically from 10 to 100 fmol and the response was linear over two orders of magnitude for most of the amino acids and carbohydrates. The HPCE system demonstrated good long-term stability and reproducibility with a relative standard deviation, less than 5% for the migration time (n=10).

Amino Acids↗
PubMed1978

An automatic interference refractometer.

Interference refractometry is a well-established method of determining the concentration of anaesthetic agents in gas mixtures. A photo-electric detector system has been fitted to a small portable, direct-reading interference refractometer to display automatically the concentration of the agent being measured. The design of the instrument is described and two possible methods of information display are suggested.

Anesthetics↗
PubMed1980

Structure of the nucleoid in cells of Streptococcus faecalis.

The structure of the nucleoid of Streptococcus faecalis (ATCC 9790) was examined and compared in the unfixed and fixed states by immersive refractometry and electron microscopy. It appears from these studies that the nucleoid structure is much more centralized in unfixed chloramphenicol-treated (stationary-phase) cells than it is in cells in the exponential phase of growth. The more dispersed configuration of the exponential-phase nucleoid could be preserved by fixation in glutaraldehyde, but not in Formalin or in osmium tetroxide. One important factor in explaining these differences in preservation is that glutaraldehyde (but not Formalin or osmium tetroxide) can rapidly cross-link the amino groups of macromolecules in cells. It was also observed that osmium tetroxide resulted in a preferential breakdown of nascent ribonucleic acid. These results are interpreted as indicating that glutaraldehyde is able to stabilize the exponential-phase nucleoid before it assumes the more central appearance seen in osmium tetroxide- and Formalin-fixed cells. These results are discussed in terms of the proposed organization of the exponential-phase nucleoid in unfixed cells.

Cell Nucleus↗
PubMed1993

Freeze-drying of cephalothin sodium: granularly agglomerated crystallization during freezing. II.

The mechanism of granularly agglomerated crystallization during freezing of cephalothin sodium (CET-Na) in aqueous solution has been discussed. Our previous report noted that strict control of the following is important in order to obtain crystalline granular agglomerates of CET-Na: (1) thermal history of the solution before receiving freezing, (2) cooling rate in freezing, and (3) aging temperature level in the crystal growth step. In order to clarify the physico/chemical meanings of the individual controls, further investigations have been made: 1) with varying thermal history, aqueous 30-% CET-Na solutions were prepared for storage, first at 0 degrees C with its supersaturation and secondly at 25 degrees C, in an unsaturated state for observing any structural changes by viscosimetry, refractometry, and surface tensiometry; 2) morphological changes in ice crystals during freezing at varying cooling rates, as well as those during the crystal growth step, were observed by polarized-light cryomicroscopy and scanning electron microscopy; 3) melting, as well as crystal growth, at several aging temperature levels were observed by electrical conductometry and also by the above-mentioned techniques.(ABSTRACT TRUNCATED AT 250 WORDS)

Cephalothin↗
PubMed1998

Measurement of urine relative density using refractometer and reagent strips.

The relative density of urine is the ratio of its density to that of water and depends on both the number and weight of solute particles in the sample, while osmolality depends only on the number of solute particles. Water metabolism is regulated by the interaction of the renal medullary countercurrent system with the circulating levels of antidiuretic hormone and thirst. The concentration of solids in urine can be measured by weighing, hydrometry, oscillations of a capillary tube, refractometry and reagent strip. These techniques, interrelated but not identical, are commonly used in hospital laboratories and in clinical wards. We compared the results obtained in 1725 urine samples of inpatients and outpatients using an automated refractometer to those obtained using two visually read dip stick tests. The correlation coefficients (Super Aution analyser vs. Aution Sticks 10EA, Aution Sticks 10 EA vs. N-Multistix, Super Aution analyser vs. N-Multisticks were 0.663, 0.645 and 0.514, respectively) and the great dispersion of mountain plots demonstrates that different techniques are not interchangeable in the measurement of relative density. Since the results obtained after discarding the samples with pH higher than 7 and those containing glucose or protein were very similar to the ones reported above, the role of these interferents appears negligible in inducing the discrepancy.

Humans↗
PubMedDate not supplied

Passive transfer of colostral immunoglobulins in calves.

Passive transfer of colostral immunoglobulins has long been accepted as imperative to optimal calf health. Many factors, including timing of colostrum ingestion, the method and volume of colostrum administration, the immunoglobulin concentration of the colostrum ingested, and the age of the dam have been implicated in affecting the optimization of absorption. The practice of colostrum pooling, the breed and presence of the dam, and the presence of respiratory acidosis in the calf also may affect passive transfer. Various tests have been reported to accurately measure passive transfer status in neonatal calves. The radial immunodiffusion and the enzyme-linked immunosorbent assay (ELISA) are the only tests that directly measure serum IgG concentration. All other available tests including serum total solids by refractometry, sodium sulfite turbidity test, zinc sulfate turbidity test, serum gamma-glutamyl transferase activity, and whole blood glutaraldehyde gelation estimate serum IgG concentration based on concentration of total globulins or other proteins whose passive transfer is statistically associated with that of IgG. This paper presents a comprehensive review of the literature of passive transfer in calves including factors that affect passive transfer status, testing modalities, effects of failure of passive transfer on baseline mortality, consequences of failure of passive transfer, and some treatment options. Many previously accepted truisms regarding passive transfer in calves should be rejected based on the results of recent research.

Acidosis↗
PubMed1999

Comparison of in vitro tests for evaluation of passive transfer of immunoglobulins in giraffe (Giraffa camelopardalis).

Serum samples from captive giraffe (Giraffa camelopardalis) were tested to assess passive transfer of immunoglobulins using in vitro methods developed for domestic ruminants. Estimated immunoglobulin levels were compared using five tests (protein electrophoresis, total protein refractometry, zinc sulfate turbidity, glutaraldehyde coagulation, and sodium sulfite turbidity). A linear relationship was observed among total protein, gamma globulin (electrophoretic measurement), and immunoglobulin level based on spectrophotometric measurement of zinc sulfate turbidity. Nonquantitative assays also demonstrated statistical correlation with the quantitative methods. Using criteria similar to those established for domestic species, cutoff values for failure of passive transfer (FPT) were established for these tests in neonatal giraffe: 1) total protein <6.0 g/dl; 2) gamma globulin < 0.5 g/dl; 3) estimated immunoglobulin level < 1,000 mg/dl (zinc sulfate turbidity); 4) glutaraldehyde coagulation test negative; or 5) no visually detectable turbidity in 16% sodium sulfite or Bova-S negative. Retrospective examination of the medical histories showed a strong statistical association between animals designated as having FPT and those that were removed from their dams based on clinical assessment to be hand-reared. Application of these tests in the field should allow earlier detection and intervention for FPT in neonatal giraffe.

Animals↗