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At least 811 records · Page 45Linked to original sources
PubMed1979

Endocrine correlates of meiosis in the male rat.

Changes in the proportion of cells within various DNA classes of dispersed testicular cells from the developing rat were monitored by microflow fluorometry and correlated with changes in the function of the pituitary (FSH), of the Leydig cells (androgens) and Sertoli cells (androgen-binding proteins, ABP). Peaks of androgens and of FSH appeared simultaneously and coincided with an accumulation of tetraploid cells and with the first appearance of haploid cells in the testis and ABP in the epididymis. Estrogen treatment (5 micrograms/day) of developing rats from day 7 completely prevented the appearance of haploid cells in the testis as well as ABP in the epididymis. In these animals the wave of tetraploid cells started and progressed normally, indicating that transformation and progression of germinal cells to the stage of the primary spermatocytes were taking place. A combined treatment with FSH and dihydrotestosterone propionate (DHTP) resulted in a premature start of Sertoli cell secretion of ABP into the epididymis, but in a normal appearance of haploid and tetraploid cells. The time correlation between peaks in FSH/androgens, the start of Sertoli cell secretion, and the occurrence of haploid cells in the testis stresses the importance of these two hormones for normal Sertoli cell function and the importance of a functional Sertoli cell for the completion of meiosis.

Aging↗
PubMed1991

Quantitative evaluation of the corneal epithelial barrier: effect of artificial tears and preservatives.

The effect of artificial tear solutions on the corneal epithelial barrier was evaluated by measuring corneal uptake of 5, 6 carboxyfluorescein (CF) after exposure of rabbit corneas to various formulations in a conjunctival cup. Four tear solutions containing 0.01% benzalkonium chloride (BAC), a formulation containing 0.001% Polyquad, a contact lens re-wetting solution containing 0.004% thimerosal, and each of the above preservatives in balanced salt solution (BSS) were evaluated. Four non-preserved solutions were also tested. After treatment with the solutions corneas were exposed to the CF, removed from the eyes and dialyzed in balanced salt solution. The CF concentration in the dialysate was measured by fluorometry. Solutions containing 0.01% BAC caused a 9.24 to 99.28 fold increase in CF uptake as compared to control. Solutions preserved with Polyquad or thimerosal caused only a 0 to 4 fold increase in CF uptake while non-preserved solutions caused no change compared to control. Corneas prepared for transmission electron microscopy using fixative containing ruthenium red exhibited damage which correlated well with CF uptake; the ruthenium red penetrated the epithelium to the basal cell layer after corneal exposure to solutions containing BAC while only superficial cell layers were stained after exposure to the other test solutions. The method used in this study allows statistical comparison of artificial tear formulations. The data show that patients with severe dry-eye who use artificial tears frequently should avoid tear solutions containing BAC and that non-preserved solutions are preferable for treatment of these patients.

Animals↗
PubMed1990

Validation and application of an assay for deoxyribonucleic acid to estimate concentrations of bull sperm.

Spectrophotometers are used for estimating sperm concentrations from raw ejaculates in semen processing laboratories. Unfortunately, these instruments have a limited detection spectrum and do not permit accurate quantification of sperm numbers in highly diluted or concentrated samples. The objectives of this study were to validate a DNA assay for quantification of sperm numbers in extended or undiluted semen samples and to determine precision of the assay. The principle of the assay is based upon a fluorescent dye that binds to adenine-thymine base pairs in double-stranded DNA. Semen samples and calf thymus DNA standards were sonicated in 2 M NaCl buffer with 1 mM EDTA. The DNA content of samples was compared to standards of calf thymus DNA using fluorometry. Sensitivity of the assay was determined to be 1.4 x 10(5) sperm cells. Concentrations of sperm estimated from DNA assay values did not differ from flow cytometric cell counts. Assays were performed in three different laboratories, using different equipment, to assess the assay's repeatability. Estimates of sperm concentrations determined by the DNA assay were similar, regardless of location and source of equipment used to perform the assays. This assay fulfills statistical criteria for being sensitive, accurate, and repeatable, and it can be employed in laboratories processing semen for artificial insemination as a tool for spectrophotometer calibration, a check for straw filling accuracy, or to quantify sperm numbers in extended, packaged semen.

Animals↗
PubMedDate not supplied

The use of optical spectroscopy in combinatorial chemistry.

Infrared and Raman spectroscopy allow direct spectral analysis of the solid-phase, thus avoiding the tedious cleavage of compounds from the solid support. With diagnostic bands in starting materials or products, infrared and Raman spectroscopy are efficient in monitoring each reaction step directly on the solid phase. Consequently, infrared and Raman spectroscopy have evolved as the premier analytical methodology for direct analysis on the solid support. While infrared transmission spectroscopy is a general analytical method for resin samples, internal reflection spectroscopy is especially suited for solid polymer substrates known as "pins" or "crowns." Single bead analysis is done best by infrared microspectroscopy, whereas photoacoustic spectroscopy allows totally nondestructive analysis of resin samples. With an automated accessory, diffuse reflection spectroscopy provides a method for high throughput on-bead monitoring of solid-phase reactions. Providing identification based on molecular structure, HPLC-FTIR is, therefore, complementary to LC-MS. Additionally, Raman spectroscopy as a complement to infrared spectroscopy can be applied to resin samples and-using a Raman microscope-to single beads. Fluorometry as an extremely sensitive spectroscopic detection method allows rapid quantification of organic reactions directly on the resin.

Chromatography, Liquid↗
PubMedDate not supplied

[The histamine and serotonin levels in the blood plasma of diabetic patients].

Fluorometry was done in 52 patients with diabetes mellitus to determine the blood plasma content of free histamine and free serotonin. The control group was 29 essentially healthy subjects. Significant increase was found out in free histamine during the stage of decompensation of diabetes mellitus (P < 0.01). With compensation of diabetes mellitus setting in, the content of histamine returns to normal (P < 0.01). The blood plasma level of free histamine can be used as an additional criterion in the assessment of compensation of diabetes mellitus. Free histamine is supposed to play an active part in the pathogenesis of diabetic angiopathies.

Adult↗
PubMed1978

[Computerized scanning analyses of FITC-labelled microscopic slides (author's transl)].

FITC-labelled virus antigen was analysed in infected cells by means of scanning-fluorometry. According to the predetermined classification the values were computerized and printed out by a mosaic printer or by a coordinate-recorder as a profile graph or a perspective image. The total impression of the 3 dimensional print-out of the quantificated topographic distribution of antigen accumulations within the cells can be optimated by variation of the angle of view.

Animals↗
PubMed2000

Usefulness of a toothbrush as a source of evidential DNA for typing.

We investigated the usefulness of a toothbrush as a source of DNA for an unidentified cadaver. Ten toothbrushes were obtained from ten individuals along with their peripheral blood. We recovered from 10 to 430 ng of DNA from all but one of the toothbrushes. All ten toothbrushes, including the one containing no detectable DNA by fluorometry, were typed correctly at all of the loci tested, including nine STRs. Three toothbrushes obtained in two actual deaths also identified two victims and one suspect. Therefore, toothbrushes seem to be useful as a source of evidential DNA for personal identification.

Cadaver↗
PubMedDate not supplied

Preparing cell suspensions from cervical smears with pepsine and ultrasonic treatment.

Since flow-through fluorometry seemed to be a workable method for prescreening cytological material, it became important to have available a reliable method of preparing suspensions of single cells with naked nuclei. An experiment was performed with cervical smears and tissue cultures exposed to varying degrees of pepsination and ultrasonication. The results were disappointing as it appeared impossible to digest cytoplasm completely without damaging the nucleus. Ultrasonic treatment appeared to have an effect only in combination with pepsin; sonication therefore is not a useful technique for dispersion of cell clusters. Moreover, a proposal found in the literature to apply sonication to effect selective damage to leukocyte nuclei was assessed but found to be unsuccessful. Pepsin treatment and ultrasonic treatment appeared conclusively to be unreliable methods for preparing suspensions of single and naked nuclei.

Cell Nucleus↗
PubMed1979

Interference of intravenous lipid emulsion with the determination of calcium in serum.

A lipid emulsion in concentrations similar to those attained after therapeutic dosages were found to interfere with the determination of total serum calcium measured by a fluorometric method. Calcium results determined by atomic absorption and by fluorometry at different concentrations of lipid emulsion were compared. When lipid concentrations were less than 100 mg/dl, centrifugation was effective in eliminating the artifactural elevation in total serum calcium. Possible reasons for the observed differences are discussed.

Calcium↗
PubMedDate not supplied

[Effects of free blood histamine on gastric acid production in patients with certain forms of iron deficiency].

The author submits data on changes in the blood plasma content of free histamine (FH) in 35 patients with iron deficiency anemia (IDA). In 25 patients IDA developed in the wake of chronic blood losses in peptic ulcer (PU)--group I. There were 12 cases presenting with non-PU concurrent IDA. The control group was 11 essentially healthy persons the same age as case patients. FH was measured with the aid of the fluorometry technique. In group I patients augmentation in the blood plasma content of FH was common as was increase in the basal secretion of hydrochloric acid. Group II patients demonstrated elevation in the blood plasma content of FH and decline in the basal secretion of hydrochloric acid.

Adult↗
PubMed2000

[Active efflux of antibiotics as multiple-antibiotic-resistance mechanism in clinical strains of escherichia coli].

OBJECTIVE: To investigate multiple-antibiotic-resistance mechanism in clinical strains of Escherichia coli. METHODS: Accumulation of ciprofloxacin in clinical isolates of Escherichia coli was measured by fluorometry, and acrAB gene was identified by PCR and Southern blot. The levels of acrAB gene expression were measured by RT-PCR. DNA fragments were sequenced by automated fluorescence sequencing. RESULTS: The state concentration of ciprofloxacin in multiple-antibiotic-resistant (Mar) strains was significantly lower than that in susceptible stsains (0.73 mg/L +/- 0.04 mg/L vs 2.00 mg/L +/- 0.07 mg/L A(660), P < 0.001). The level of acrAB gene expression in Mar strains was significantly higher than that in other strains. No deletion or point mutation in acrAB gene were found in Mar and susceptible clinical Escherichia coli isolates. CONCLUSIONS: High expression of acrAB gene leads to multiple-antibiotic-resistance in clinical strains of Escherichia coli, and Mar operon may contribute to the regulation of acrAB gene expression.

Anti-Bacterial Agents↗
PubMedDate not supplied

Computer-operated scanning analysis of FITC-labelled measles virus in cell cultures.

FITC-labelled measles virus antigen in infected cells was analysed by computer-operated scanning fluorometry, printed out by a mosaic printer according to a predetermined classification, and by a coordinate-recorder as a perspective image. The three-dimensional print-out of the topographic distribution of antigen accumulations in the cells can be optimized by a variation of the angle of view.

Animals↗
PubMed1975

[Analytical methods I].

The most frequently used methods such as spectrophotometry, fluorometry, etc., for the analysis of drugs in biological fluids are compiled. The usefulness of quantitative chromatographical procedures is also mentioned. Reliability criteria of these assays are extensively discussed and some results are compared to those found by other methods like labelling and microbiology.

Biological Assay↗
PubMed1992

Glycolytic oscillation and effect of metabolic inhibitor on rat lens.

Abnormalities in glucose metabolism are thought to be among the main causes of cataract formation. We have taken noninvasive biochemical measurements of the lens which provides us with information concerning glucose metabolism in the lens epithelium. The autofluorescence of reduced pyridine nucleotides (PN) and oxidized flavoproteins (Fp) in the rat lens epithelium was measured noninvasively as a function of time using redox fluorometry. The oscillations of the metabolic ratio, PN/Fp, were measured in vivo, in situ, and in the organ-cultured lens. The PN/Fp ratio in the organ-cultured lens ranged from 1.05 to 2.57 within a period of 60-90 minutes (mean +/- SD = 1.52 +/- 0.36). This PN/Fp ratio increased by 23% when a respiratory inhibitor (8 mM KCN) was applied to the lens. However, it decreased by 10% in the presence of a complete metabolic inhibitor (8 mM iodoacetamide). The presence of metabolic oscillations in the in vivo, in situ and cultured lens indicates that this oscillation is a local phenomenon. In cell-free extract systems, oscillations of several intermediates in the glycolytic pathway have been previously demonstrated and this PN/Fp oscillation is thought to be a reflection of glycolytic oscillation.

Animals↗
PubMed2003

[RNA/DNA ratio as an index of physiological condition of Colossoma macropomum and Piaractus branchypomus (Pisces: Characiformes) during embryonic development].

We evaluated RNA/DNA ratio as an index of physiological condition during larval development of a hybrid between the fishes Colossoma macropomum (cachama) and Piaractus brachypomus (morocoto). The samples were obtained by induced reproductive technology and the eggs were maintained in acrylic conical incubator with a continuous waterflow. Embryonic development, from egg fertilization to cell division and hatch out, took 12 hours 20 minutes at 29.5 degrees C, dissolved oxygen contents of 6.0 ppm and pH 7.5. Nucleic acids quantification was determined by fluorometry with ethidium bromide and Hoechst 33258 dyes. We observed significant changes of RNA/DNA ratios during all stages of the embryonic larval development. Therefore, RNA/DNA relation is an useful technique to evaluate physiological condition in short period and could be utilized as nutritional condition and/or instantaneous growth for routine check to verify the health status in early life of cultivated species.

Animals↗
PubMed2004

[Spectroscopic evaluation of time-resolved fluoroimmunoassay].

The lanthanide trivalence ion and its chelates are used for marking substance in Time-Resolved Fluorescence Immunoassay (TRFIA), marking protein, hormone, antibody, nucleic acid probe or biologic alive cell, to measure the concentration of the analysis substance inside the reaction system with time-resolved fluorometry after the reaction system occurred, and attain the quantitative analysis's purpose. TRFIA has therefore become a kind of new and more sensitive measurement method after radioisotope marking, enzymatic marking, chemiluminescence, electrochemiluminescence, primarily depending on the special physics and chemistry characteristics of lanthanide trivalence ion and its chelates. In this paper, the result of spectroscopic evaluation of europium trivalence ion and its chelate, and the principle of time-resolved technology and fluorescence-enhanced technology are reported. At the same time, the experiment shows that the excitation wavelength chosen between 336 and 337 nm benefits the excitation and the energy transfer of chelate diketone of europium trivalence ion.

Europium↗
PubMed2004

[Determination of platelet serotonin by high performance liquid chromatography with fluorometric detector].

OBJECTIVE: To establish a simple, rapid and precise method to determine platelet serotonin. METHODS: Serotonin (5-hydroxytryptamine; 5-HT) was determined in platelet pellet after simple deproteinization, following ion-pair high performance liquid chromatography (HPLC) on reverse-phase column: Nova-pak C18 column (150 mm x 4.6 mm, 4 microm), serotonin and internal standard (N-methylserotonin) were detected by fluorometry. RESULTS: The intra-day CV was 2.29% and inter-day CV was 3.88%. The mean recovery of serotonin in platelet was 97.5%, the linear range was 20 - 20000 nmol/ L, and the detection limit was 1 nmol/L. 5-hydroxyindole acetic acid (5-HIAA), Trp, Phe and Tyr had no interference with the chromatographic condition used in this trial. CONCLUSION: The metod described here is simple, convenient, rapid, sensitive, and accurate for clinical and scientific research.

Adult↗
PubMed1992

Muscle flap monitoring in a rat model with a variable gain quantitative fluorometer.

A variable gain dermofluorometer with a wide range of sensitivities capable of quantifying fluorescein emission from both skin and muscle was tested in a rat latissimus dorsi island muscle flap model. Quantitative fluorometric readings directly from muscle and skin sites that did not undergo surgery were taken at intervals over 2 hours after intravenous fluorescein injection. Muscle flaps with intact pedicles gave an inflow-outflow pattern. A no-outflow pattern was seen in muscle flaps with ligated pedicle veins and a no-inflow pattern was seen in muscle flaps with ligated pedicle arteries. These patterns were similar to the flow pattern seen with quantitative fluorometric monitoring in flaps with cutaneous components. These results suggest that quantitative fluorometry may be applicable to circulation monitoring in muscle flaps.

Animals↗