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PubMedDate not supplied

Analysis of the degree of conversion of LED and halogen lights using micro-Raman spectroscopy.

This study determined the degree of conversion of two LED (light-emitting diodes) (Elipar FreeLight [FL], 3M ESPE; GC e-Light [EL], GC), a high intensity (Elipar TriLight [TL], 3M ESPE) and a very high intensity (Astralis 10 [AS], Ivoclar Vivadent) halogen light. The degree of conversion of these lights was compared to a conventional halogen light (Max [MX] (control), Dentsply-Caulk). Ten different light curing regimens, including pulse (EL1), continuous (FL1, EL2, TL1), turbo (EL3, AS1) and soft-start (FL2, EL4, TL2) modes of various lights were also investigated. Composite specimens of dimensions 3 x 3 x 2 mm were cured with the 10 different light curing regimens investigated. Micro-Raman spectroscopy was used to determine the degree of conversion at the top and bottom surfaces of a composite restorative (Z100, [3M ESPE]) at 60 minutes post-light polymerization. Five specimens were made for each cure mode. The results were analyzed using ANOVA/Scheffe's post-hoc test and Independent Samples t-tests at significance level 0.05. The degree of conversion ranged from 55.98 +/- 2.50 to 59.00 +/- 2.76% for the top surface and 51.90 +/- 3.36 to 57.28 +/- 1.56% for the bottom surface. No significant difference in degree of conversion was observed for the 10 light curing regimens when compared to MX (control). The curing efficiency of LED lights was comparable to halogen lights regardless of curing modes.

Analysis of Variance↗
PubMed2004

[Visual cycle and dark adaptation: a new approach in research].

Visual cycle is the series of reactions that support regeneration of the visual pigmen after its photolysis in retinal rods and cones. Inherited or acquired deficiencies of the visual cycle impair dark adaptation and lead to a series of visual disorders. The paper describes a new approach to study of the visual cycle that uses fast dichroic microspectrophotometer. The method allows studying interconversion of bleaching products in single intact photoreceptors in condition approaching the situation in vivo. Using this approach, we established a complete scheme of transitions between metarhodopsins, retinal and retinol in amphibian rods. It appeared that the decay of metarhodopsins controls both the time course of rod dark adaptation following small bleaches and the production of retinol that is the substrate for rhodopsin regeneration. We also obtained novel data on kinetics of the decay of cone metapigments that was found to be by an order of magnitude faster than in rods. Possible application of the method for further study of the visual cycle in normal and pathological conditions is discussed.

Amphibians↗
PubMedDate not supplied

Exploring the nature of acid-resistant hybrid layer with wet bonding.

The nature of the hybrid layer (HL) following chemical treatment has not been resolved. The effects of chemical treatments and polishing on HL morphology and composition were investigated using micro-Raman spectroscopy and SEM. Polished and unpolished SingleBond adhesive/dentin (a/d) interfaces from the same tooth were randomly selected for one of the following treatments: a) 5N HCl followed by 5%NaOCl; b) 5%NaOCl; c) 5%NaOCl and sonication; d) 5%NaOCl followed by 5N HCl. The results indicated that the HCl-NaOCl treatment could obscure the "true" HL in the unpolished a/d interfaces that were actually porous. The composition and morphology of the polished interface specimens were largely unchanged by the above treatments. Descriptions of HL quality are commonly based on the acid reactivity of polished specimens. The results of this study indicate that polishing dramatically alters the native composition, increasing its acid-resistance, and thus, this procedure could lead to false conclusions about HL quality.

Bisphenol A-Glycidyl Methacrylate↗
PubMed1985

Microphotometric quantitation of succinic dehydrogenase in whole isolated osteoclasts.

The microphotometric quantitation of succinic dehydrogenase (SDH) in whole isolated osteoclasts was performed. Osteoclasts were obtained from imprints of the external metaphyseal area of tibia, a zone of physiological bone resorption. SDH was demonstrated histochemically and the reaction product was measured in a Zeiss Cytoscan microphotometer in arbitrary units (AU) of activity from 0 to 500. Total enzyme activity (TEA) was 10 to 50 AU in 78% of the cells. The enzyme concentration (MEC), taken as the activity per unit volume was 0.10 to 0.40 AU in 94% of the cells. Values of reactive cytoplasm area (RCA) were high for most of the cells, but lower for a few, probably mononuclear, osteoclasts. The correlation index for TEA vs RCA was significant. The study of enzyme activity in whole osteoclasts by microphotometric quantitation has been proven possible. This technique could be employed in further studies of enzyme activity of osteoclasts in other physiological or pathological states of bone resorption.

Animals↗
PubMed2005

[The microspectrophotometric criteria in estimating gastric mucosa dysplasia in non-invasive adenocarcinoma].

Computer analysis was carried out of images of changes in area and ploidy of gastric mucous nuclei associated with concomitant pathology, dysplasia and non-invasive adenocarcinoma of the stomach. In grave dysplasia, the area and ploidy of a nucleus were 213.7 +/- 3.42 microm2 and 10.2 +/- 0.2 c, and in well- or moderately differentiated cell adenocarcinoma--333.8 +/- 16.5 microm2 and 14.95 +/- 1.9 c, respectively. It is suggested that this evidence can contribute to a more accurate estimating of pathological processes taking place in the gastric mucosa when differential diagnosis between dysplasia and stomach cancer is undertaken.

Adenocarcinoma↗
PubMed1991

A comparative study of quantitative stains for DNA in image cytometry.

In this study we examined the reproducibility of several stains used to measure nuclear DNA by image cytometry. The specimens were touch preparations of liver and testis from mouse and liver, intestine and brain from rat, fixed in either neutral formalin or Carnoy's solution. The tested stains included four Feulgen methods (pararosaniline, azure-A, thionin and acriflavine), the gallocyanine-chromalum stain and two fluorescent stains (acridine orange and propidium iodide). Absorbance measurements employed a video image analysis system; fluorescence measurements were from a scanning microspectrophotometer. The acriflavine-Feulgen stain was analyzed for both absorbance and fluorescence. All seven stains were quantitative for DNA and gave reproducible results. The absorbance measurements had a lower coefficient of variation (CV) than the fluorescence values. In a nested analysis of variance of the pararosaniline Feulgen stains, cell-to-cell variability accounted for 67% of the total variance; slide-to-slide, 9%; and batch-to-batch, 24%. These values did not change significantly when the staining was performed in an automatic staining machine. For DNA analysis using image cytometry, we conclude that the Feulgen staining technique is the most useful. In particular, acriflavine-Feulgen-stained cells fixed in Carnoy's fluid give the least variation between measurement values and the most accurate ratios between the separate ploidy groups. For fluorescence cytometry we recommend Carnoy's fixation and the acriflavine-Feulgen stain because of its narrow CV as compared to acridine orange and propidium iodide.

Analysis of Variance↗
PubMed1991

[The morphogenesis of polyps of the large intestine].

The proportion of so-called hyperplastic polyps among other colon epithelial tumours remains unclear. Colon polyps are studied in 400 patients: hyperplastic polyps are found in 107, a combination of hyperplastic polyp with tubular adenoma in 143, tubular adenoma in 72, villous adenoma in 41 and tubulovillous adenoma in 37 cases. Hyperplastic structures and formation of adenomatous structures were, as a rule, observed in a polyp tip, this corresponding to the increase of nuclei volume and DNA amount in the tip colonocytes. The determination of karyometric coefficient (the ratio of the colonocyte nuclei volume in the polyp tip to colonocytes in the intact mucosa) is proposed as a quantitative criterion of proliferative and dysplastic processes.

Colon↗
PubMed1991

Spectrokinetic characteristics of two types of fluorescence of refractive granules in native individual cells from ascitic tumours.

The spectrokinetic parameters of two different types of fluorescence of lipid-containing refractory granules (RG1 and RG2) specific to native single cells from rat ovarian tumour and Zaidela ascites hepatoma were studied. With these parameters it was possible for the first time to reveal and estimate the contribution of fluorescent lipid peroxidation products to the total fluorescence band (430-470 nm) of RG1 as well as to reveal another fluorescent component with parameters similar to those of NAD(P)H. The phenomenon of 'photoinflammation' of RG2 fluorescence under UV light, reported previously for lipofuscin granules, was observed in vitro for four retinal derivatives, but only in the absence of their contact with air.

Animals↗
PubMed1991

[Cytoplasmic RNA in neocortical neurons in vitro].

The investigation of the ratio of neuronal cytoplasmic RNA mono- and two-chain sections was performed in thin neocortical slices by means of fluorescent probing. Changes of the relative intensity of Acridine Orange red luminescence indicated a decrease in the quota of monochain sections in the common neuronal RNA pool. In eight hours of superfusion it was authentically less than in the control slices and in the slices which were incubated during four hours. Deep profiles of red fluorescence became plane in the process of incubation. It was suggested that the essential decrease in the red luminescence intensity of cytoplasmic RNA in vitro, observed between four and eight hours, may be conditioned by disintegration of polysomes to monosomes, and this, in its turn, may cause the decrease in ribosomal synthetic activity.

Acridine Orange↗
PubMed1990

A Feulgen microspectrophotometric study of the DNA content of essential fatty acid-deficient rat pancreas treated with nitrosomethylurea.

Microspectrophotometric DNA measurements in exocrine pancreas of essential fatty acid-deficient (EFAD) and EFA-sufficient (EFAS) rats which received a single intraperitoneal injection of the carcinogen nitrosomethylurea (NMU) or saline (SAL) was the subject of the present report. The DNA content of acinar pancreatic cells of SAL-injected EFAD and EFAS rats was diploid. NMU-induced pancreatic focal acinar cell hyperplasia (FACH) had one main cell population with a diploid content, whereas in the intervening parenchyma there were diploid and tetraploid cells. The number of tetraploid cells was smaller in EFAD rat pancreas than in EFAS indicating a diet dependent effect. NMU-induced FACH had a diploid distribution pattern indicating that cells are in a G1, quiescent phase, contrasting with AZA-induced similar lesions which showed an abnormal ploidy. It remains to be established whether DNA phenotypic traits of NMU and AZA induced FACH reflect the neoplastic potentials of both types of lesions. The decreased number of tetraploid cells in EFAD rat pancreas is in keeping with data indicating a promoting effect of the EFA linoleic and arachidonic acids on growth rate of certain cell populations in vitro.

Animals↗
PubMed1990

Heterogeneity of DNA distribution pattern in colorectal carcinoma. A microspectrophotometric study of fine needle aspirates.

For 50 consecutive patients with colorectal carcinoma, the nuclear DNA content in four separate fine needle aspiration samples taken from the resected tumors was analyzed using single-cell Feulgen cytometry. The DNA distribution patterns were divided into four classes according to their degree of euploidy/aneuploidy. Twenty tumors (40%) displayed a similar DNA pattern in all four samples while 30 tumors (60%) were heterogeneous, with a different DNA pattern within one or more of the four samples. None of the tumors were homogeneously diploid. These results illustrate the importance of multiple biopsy samples in the evaluation of the DNA pattern in colorectal tumors.

Adult↗
PubMed1990

[Quantitative study on esophageal cytology. II. Measurement of DNA contents of normal, dysplastic and malignant squamous cells of the esophagus].

The relative DNA contents of normal esophageal squamous epithelial cells, hyperplastic, dysplastic (grade I and II), nearly malignant and early malignant squamous epithelial cells of the esophagus were measured in 74 cases by microspectrophotometric technique. The results showed that from normal cells to early stage of malignancy, the DNA contents gradually increased with the increase in severity. In addition, the distribution of DNA values became broader; the peak DNA values shifted to the right, reduced and disappeared. In the meantime, aneuploid cells appeared. There was a definite positive correlation between DNA content and nuclear area in precancerous dysplasia (r greater than 0.9). The results indicate that the current grading of esophageal cytology has its quantitative biochemical basis.

Aneuploidy↗
PubMed1990

[The detection of lipofuscin in a culture of hybridoma cells].

Lipofuscin granules (LG) are found in the cultured hybridoma cells producing monoclonal antibodies to phage. LG have been studied using light and electron microscopy. Luminescent spectra of LG clusters in hybridoma cells are presented. The increase of own luminescence intensity of LG in the course of excitation by ultraviolet (365/nm) is shown. The advantages of hybridoma cells culture for investigation of LG on the cell level are discussed.

Animals↗
PubMed1986

Comparative cytospectrophotometry of Wright-stained erythroid cells of vertebrates.

Visible spectra of erythroid cells stained with Wright's method were studied microphotometrically. Most mature cells of vertebrates have the main peak at 520 nm (A 520) and accessory peaks at 410 nm and 600 nm (A 410 and A 600), respectively. To compare the absorption at 520 nm against 410 nm and 600 nm, the relative absorption spectra were determined and effectively shown as percentage ratios (RAs) to the main peak of A 520. The A 520 shifted to the shorter side of the wavelengths in birds and lower vertebrates. When the RA values of 410 and 600 nm were compared, it was observed that RA 410 of immature cells was less than that of mature cells (15%), and that immature cells of the lower RA 410 type were present in peripheral blood, as well as in bone marrow of vertebrates. Thus, photometric analysis of erythroid cells at RA 410 and RA 600 against A 520 seems to provide useful parameters for comparative studies on vertebrate erythroid cells. Six spectral types can be observed in vertebrate erythroid cells by these parameters.

Amphibians↗
PubMed1989

DNA and nuclear protein characteristics in non-neoplastic and neoplastic endometrial tissue.

Feulgen-DNA and nuclear protein (NP) measurements were performed on non-neoplastic and neoplastic endometrium. Non-neoplastic endometrial cells were exclusively characterized by euploid nuclear DNA content. The NP content may vary significantly in relation to the proliferative stage as reflected by a 2-3-fold increase NP/DNA ratio in growing as compared to growth arrested cells. Endometrial adenocarcinomas could be subdivided into euploid and aneuploid types. The euploid tumors were found to exhibit DNA and NP characteristics comparable with those of normal tissue. In contrast, aneuploid tumors showed DNA and NP characteristics indicating increased proliferative activity as well as a pronounced disorder between the DNA and protein cycle.

Biomarkers, Tumor↗
PubMed1989

[Relationship between the effectiveness of CDDP therapy and the nuclear DNA content in advanced-recurrent gastric cancer cases].

A microspectrophotometric analysis of the DNA content has been performed on 9 advanced recurrent gastric cancer patients with measurable lesions, who has either been treated by CDDP alone or with other chemotherapeutics during a three-year period since, 1984. Histograms of the DNA content were classified into four ploidy patterns. All of the 4 responder cases (CR, PR, MR) showed type, IV, although only one of 5 non-responder cases revealed the same typing. In one of the two CR cases the DNA ploidy pattern, which was examined before and after the therapy, changed from type IV to type II. Thus it appears that an analysis of the DNA content may be useful in evaluating the effectiveness of different chemotherapies.

Adult↗