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Query: UMLS:C0432222 (SEM)
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Experiments were conducted to assess protein solubility in .2% KOH as an indicator of soybean protein quality for chicks and pigs and to assess effects of particle size on protein solubility. As the particle size (micron) of soybean meal (SBM) increased, protein solubility (%) decreased (b = -.0206). In two 9-d chick trials, dehulled SBM (48% CP) was subjected to various autoclaving times and then fed as the sole source of dietary protein to young chicks. Increasing autoclaving times from 0 to 40 min at 120 degrees C resulted in a quadratic decrease in protein solubility. A broken-line model was fitted wherein gain:feed of chicks was plotted as a function of protein solubility. The analysis showed no reduction in feed efficiency with solubilities greater than 59 +/- 1.5% (mean +/- SEM). When solubility was below 59%, however, gain:feed decreased 1.5% for each 1% decrease in protein solubility. The third trial (13 d) was conducted with 7.5-kg pigs fed autoclaved SBM (44% CP) as the primary source of protein. Feed efficiency was significantly decreased when protein solubility was less than 66%. This study showed that protein solubility in KOH was a good index of in vivo soybean protein quality, and that it is important to standardize SBM particle size when applying the KOH assay.
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PMID:Soybean protein solubility in potassium hydroxide: an in vitro test of in vivo protein quality. 188

To determine intracellular Ca2+ concentrations more accurately, we examined Kd of Fura-2 for Ca2+ in conditions which were systemically changed. In a solution comprising of 150 mM KCI, 20 mM MOPS-KOH, pH 6.94, 60-100 microM EGTA and 1 microM Fura-2, Kd at 20 degrees C was 0.266 +/- 0.016 microM (mean +/- SEM) (21 determinations). The ionic strength (I) of the solution strongly affected Kd: the relation of -log Kd versus 2 square root of I/(1 + square root of I) - 0.4.I was 3.6 times as steep as that of EGTA. Kd was moderately changed by pH higher than 7.1, while it was very slightly changed by pH between 6.7 and 7.1. Kd was minimally affected by temperature. The apparent Kd values for Ca2+ in the presence of various concentrations of Mg2+ gave an estimate of the Kd for Mg2+ of about 100 mM, which is about 10 times as great as the estimated value by Grynkiewicz et al. [1]. This estimation assumes competitive binding between Ca2+ and Mg2+ for Fura-2. However, the possibility that Mg2+ may bind Fura-2 in a more complicated way is also suggested. Co-existing proteins in the solution dose-dependently increased an apparent Kd, independent of the type of proteins used, up to a limiting value of about 1.0 microM. With the ratio method, the Ca2+ concentration which gives (Rmin + Rmax)/2 is Kd.beta. The range of Ca2+ concentrations on which R values show steep dependence is determined not only by Kd but also by beta. This means that the excitation spectra and pair of excitation wavelengths selected as well as Kd are critical factors.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Reassessment of Fura-2 and the ratio method for determination of intracellular Ca2+ concentrations. 201 20

The formation of calcium fluoride (CaF2) was measured on sound enamel (SE) and in caries-like enamel lesions (CL) after treatment in vitro with 2% neutral NaF or Duraphat. The caries-like lesions were created by exposure to acidified gel at pH 4.5 within a 0.07-cm2 window punched in water-repellant tape. The same window area was used in series (n = 10) of SE or CL during the application of NaF for 1 or 5 min or for 18 h or Duraphat for 6 or 18 h. CaF2 was extracted with 1 M KOH for 24 h, and fluoride was determined by gas chromatography. The short-term applications of NaF produced only negligible amounts of CaF2 on SE. The amounts of CaF2 in CL after 5 min application of NaF corresponded to (mean +/- SEM) 27 +/- 2.0 micrograms F/cm2. More than half of this amount was observed after only 1 min exposure to the NaF solution. The quantities of CaF2 in CL were similar after 6 and 18 h application of Duraphat, amounting to 26 +/- 2.2 and 31 +/- 2.2 micrograms F/cm2, respectively, suggesting that the reaction was essentially terminated after 6 h. These amounts were only about one fourth of the quantity obtained after 18 h exposure to the NaF solution. Thus, the conventional 5-min treatment with NaF produced the same amount of CaF2 in CL as 6 or 18 h exposure to Duraphat.
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PMID:Formation of CaF2 on sound enamel and in caries-like enamel lesions after different forms of fluoride applications in vitro. 205 82

The clinical outcome and the effects on morphogenesis and cell ultrastructure induced by a 1% ciclopiroxolamine solution in six patients with proven pityriasis versicolor were studied. Treatment regimens consisting of a once-daily application for 1 day, 2 days (Days 1 and 4) or 3 days (Days 1, 4 and 8). Clinical evaluation, scanning (SEM) and transmission electron microscopy (TEM) were performed on skin scrapings before treatment, and at 3, 7, 15 and 21 days after the start of therapy. SEM techniques have shown severe changes in the surface ultrastructure of yeasts and hyphae of Pityrosporum spp. (Malassezia furfur) 15 days after the start of therapy. TEM techniques showed extensive internal disruption, mainly severe necrosis of the cytoplasm, 3 and 7 days after the start of treatment. However, KOH direct microscopy showed apparently normal morphology of Pityrosporum spp. (Malassezia furfur) at all assessment points. The final clinical cure in all the patients was achieved 21 days after the start of therapy.
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PMID:Changes in fungal ultrastructure after short-course ciclopiroxolamine therapy in pityriasis versicolor. 234 14

We have characterized specific receptors for tetradecapeptide somatostatin (SS-14) of rat brain using 125I-labeled Tyr11-SS-14([125I-Tyr11]SS-14) as radioligand. [125I-Tyr11]SS-14 binding was sensitive to time, pH, temperature and ionic strength of the buffer, and was optimal in 50mM HEPES/KOH buffer, pH 7.5, at 25 degrees C for 60 minutes. Scatchard analysis indicated that the rat forebrain membranes had a single binding site with an apparent dissociation constant (Kd) of 0.522 +/- 0.044 nM and maximum binding capacity (Bmax) was 233 +/- 37 fmol/mg protein (mean +/- SEM). Ca2+, Mg2+, Mn2+ and Co2+ had a significant effect on the specific binding, which indicates that these metal ions might affect somatostatin receptor activity in the brain. Among CNS acting drugs, Ca2+ antagonists, antischizophrenic drugs, antidepressants and anticholinergic drugs had relative effects on [125I-Tyr11]SS-14 bindings to rat cerebral cortex membranes.
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PMID:Biochemical and pharmacological characterization of somatostatin receptors in rat brain. 257 1

In this paper are presented the results of a chemical analysis of partially demineralized enamel lesions positioned under plaque in vivo for 3 weeks. During the experimental period the samples were brushed with fluoridated or non-fluoridated toothpaste systems. After the experiment the fluoride and protein uptake was determined. Furthermore, KOH extractions of the lesions were carried out and the solutions analyzed for calcium, fluoride, and phosphate. The results show that 'CaF2-like' material is most likely formed inside lesions during the in vivo period. This in indicated from chemical analysis, Raman spectroscopy, and SEM observations. The amount of CaF2-like material is on the order of 0.1 wt% if we consider its formation all over the enamel lesions, or 1 wt% if we assume its formation in interprismatic regions of the enamel only. About 40% of the fluoride taken up from toothpaste systems is in the form of CaF2-like material. In vivo there is a substantial influx of proteins (approximately 0.3%) and also a very large influx of phosphate ions. The effect of CaF2-like material is most likely strongly dependent on conditions in the lesion, such as pH change.
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PMID:'Calcium fluoride-like' material formed in partially demineralized human enamel in vivo owing to the action of fluoridated toothpastes. 321 42

Raman spectra containing the distinct band at 322 cm-1 due to CaF2 or CaF2-like material formed in/on fluoridated bovine enamel were recorded using a micro-Raman spectrograph. Due to increasing levels of background fluorescence with increasing thickness of enamel, the Raman measurements were carried out on thin regions of wedged enamel sections. The distribution of the CaF2 or CaF2-like material was estimated using a simple model. The results indicate that 1/3 of the total CaF2 was concentrated within the narrow depth < 2 microns with high CaF2 concentrations (> 10 wt%), and that the majority of the CaF2 was distributed over the depths up to 26 microns (1 wt% CaF2). SEM observations on fractured fluoridated enamel confirmed that morphological changes were present in the depth range comparable to that of the high CaF2 concentration region expected from the Raman analysis. In deeper regions where lower concentration (< 10%) but a large amount of CaF2 was still expected, the SEM images failed to distinguish between the normal and fluoridated enamel. After KOH treatment, the Raman spectra did not show evidence of the CaF2 peak and the SEM micrographs also confirmed the removal of globules. The peak position of the Raman band of the CaF2 formed by the fluoridation was identical to that of pure CaF2. However, the linewidth was 23 cm-1 (FWHM) and a factor of 2 broader than that of pure CaF2 (12 cm-1). This implies that the lattice dynamics of the CaF2 formed by fluoridation is different from of pure CaF2, and that the material formed is 'CaF2-like' or 'disordered CaF2'.
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PMID:Combined Raman and SEM study on CaF2 formed on/in enamel by APF treatments. 828 57

The formation of CaF2 was measured on sound enamel and in artificial, standardized (acidified gelatin, pH 4.5) caries-like enamel lesions after exposure to: (a) dentifrice/saliva slurries adjusted to relevant F-concentrations of approximately 100 or 8 ppm by appropriate addition of 1,000 ppm F NaF or Na monofluorophosphate (MFP) dentifrice, respectively, or (b) a mixture of saliva with a 0.2% NaF solution obtained by a usual 1-min rinse procedure or an aqueous solution of 0.2% NaF. CaF2 was determined after extraction with KOH and fluoride analysis by gas chromatography. Only negligible amounts of CaF2 were produced on sound enamel ranging from (mean +/- SEM) 0.76 +/- 0.14 micrograms F/cm2 with the 0.2% NaF solution to as little as 0.04 +/- 0.06 with the MFP dentifrice slurry. In caries-like enamel lesions, the CaF2 production with the 0.2% NaF solution/saliva mixture corresponded to 3.7 +/- 0.4 micrograms F/cm2 and corresponding amounts obtained with the dentifrice/saliva slurries were 1.5 +/- 0.19 micrograms F/cm2 with NaF, but only 0.19 +/- 0.04 with MFP. It was suggested that the deposition of CaF2 in the micropores of early lesions can be expected to be an important mechanism with F rinses, probably to some extent with NaF dentifrices, but barely with MFP dentifrices. The formation of CaF2 on sound enamel is unlikely to play a significant role in the caries-reducing effect of F rinses and F dentifrices.
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PMID:Calcium fluoride formation in enamel from semi- or low-concentrated F agents in vitro. 831 62

The present study examined the enamel surface after in vitro topical treatments with a neutral 2% NaF solution. For minimising the risk of artefacts, samples were inspected without pre-treatment as fresh, naturally wet specimens by complementary techniques: variable pressure electron microscopy (VP-SEM) and confocal laser scanning microscopy (CLSM). VP-SEM provided information on the surface morphology, whereas CLSM allowed non-destructive visualisation of subsurface areas. Neutral NaF solutions induced globular precipitates on the enamel surfaces. If the globules formed may be described as "calcium fluoride like material", the additional information of this experiment is that, after interaction with neutral solutions, they also contain considerable amounts of NaF. When the NaF solutions were soaked on pellets and then were brought into contact with the enamel surfaces, NaF crystallites of cubic shape are formed. Confocal optical tomographies of subsurface enamel after treatments with neutral NaF solutions revealed partly coroded enamel structures, whereas VP-SEM showed intact surfaces. In between the coroded areas, a fine granulate precipitate could be observed. This is evidence that fluoride induces the formation of sub-surface precipitates only when applied during demineralisation. The precipitate could be readily removed by 24-h contact with a KOH solution.
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PMID:Fluoride-induced precipitates on enamel surface and subsurface areas visualised by electron microscopy and confocal laser scanning microscopy. 939 11

Macroscopic researches on heart vascularization have indicated that the angioarchitecture of the conducting system differs from that of the normal myocardium. In order to observe this variance, eight cow hearts were dissected for perfusion through the Ramus ventricularis dexter and Ramus septalis of the A. coronaria dextra with Ringer's solution, and then injected with Mercox. After corrosion in KOH the casts were prepared for observation in a SEM. In the region of the sinoatrial node no special capillary arrangement was observed, but only valves on the venous side. At the atrioventricular node and the bundle of His, the arterioles showed a diffuse formation, filling this area with a regular caliber, without any special capillary orientation. The arteries that reach the right bundle dichotomized and ran collateral to the opposite extremity of this structure, lying parallel. The vessels with the biggest caliber were deeply positioned. In the left bundle the arterioles showed a net like figure, mainly in one plane. Following the form of the bundle, and below the conducting tissue a big anastomotic venous arrangement is observable.
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PMID:The microangioarchitecture of the conducting system in cattle. 1056 14


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