Densitometry

Quantitative ultrasound has attracted significant interest in the evaluation of bone fracture healing. Animal and clinical studies have demonstrated that the propagation velocity across fractured bones can be used as an indicator of healing. Researchers have recently employed computational methods for modeling wave propagation in bones, aiming to gain insight into the underlying mechanisms of wave propagation and to further enhance the monitoring capabilities of ultrasound. In this paper, we review the relevant literature and present the current status of knowledge.

Major technical progress in the development of computer-based image analysis has made possible the entry of autoradiography and immunohistochemistry into a new era where quantification by densitometry has become easily accessible. Autoradiography could become quantitative and displayed adequate reproducibility with the help of emulsion-coated films and the use of scales of standards of known radioactivity exposed and analyzed in parallel to the tissue sections.Immunohistochemistry after revelation by a color-based enzymatic technique can also become quantitative, providing that standardization of the crucial steps of the procedure and calibration through a parallel treatment ofa scale of antigen standards can be ensured. Such an approach is described here in the rat with reference to tyrosine hydroxylase (TH), the main synthesizing enzyme for catecholamines, and with dopamine (DA) itself, a catecholaminergic neurotransmitter. The different parts of the procedure, which can influence the results, such as the fixation of the animals by perfusion and the evaluation of the fluctuations via the calibration curve, are discussed in detail.Biological validation of the proposed procedure is described by reference to experiments already well documented biochemically, such as the induction effect of reserpine on TH in the rat locus coeruleus and the depleting effect of α-methyltyrosine (AMPT), a well-known blocker of TH activity, on rat striatal DA content. Finally the importance of restricting the measurements to the (pseudo)linear portion of the calibration curve is illustrated by the autoradiographic identification of the differential intrastriatal repartition of the dopaminergic D1 and D2 receptorsites, particularly the dual patch-matrix compartments.

The optical properties of four currently ysed and two recently introduced maxillofacial prosthetic materials were evaluated after the materials were subjected to the following seven environmental variables: natural weathering; normal aging; two types of adhesives; two types of cleaning agents; and cosmetics. Optical density and color changes were evaluated. The currently used silicones Silastic 4-4210 and Silastic 4-4515, Medical Adhesive type A material, and polyurethane all showed more changes in color and optical density than the newly introduced silicone A-102 material. (J PROSTHET DENT 1992;68:820-3.)

This report describes separation and detection of chlorophenoxy acid herbicides spiked in drinking water by the technique combining solid-phase extraction, fieldamplified sample stacking, capillary electrophoresis, and potential gradient detection. The herbicide solution (400 mL) was concentrated to 0.1 mL by the solid-phase extraction procedure. The buffer containing 3 mM ammonia and 0.3 mM hydroxypropyl-bcyclodextrin was adjusted to pH 9.0 with ammonia. The sample solution was injected into the capillary to 30% of the whole length, and 29 kV and 9 kV were employed for field-amplified sample stacking and separation, respectively. The herbicides were baseline separated and the detection limits with the above combined techniques were in the range of 1-4610 22 ng/mL.

A series of biochemical, staining and electron microscopy techniques were utilized to investigate the mechanisms of C-and G-banding. These led to the following conclusions. I. The treatment of fixed chromosomes with 0.07 N NaOH for 30 to 180 set removes from 16 to 81% of the DNA from the chromosomes. 2. On average, the complete C-band technique removes 60% of the DNA. 3. This DNA is preferentially extracted from the non-C-band regions. 4. In marked contrast to this, all G-band techniques (except 1) removed less than 9 o,, of the chromosomal DNA. 5. Most of the G-band techniques, including those using trypsin, remove very little protein from the chromosomes. 6. Feulgen staining indicated that neither C-nor G-banding can be explained on the basis of different amounts of DNA along the length of the chromatid. 7. Treatment of chromosomes witkalkali or prolonged treatment with trypsin tends to destroy G-bands, while C-bands remain. 8. The combined use of acridine orange and Giemsa staining indicate that, (a) repetitious DNA in situ renatures in seconds while non-repetitious DNA renatures in minutes; (6) Neither C-nor G-banding depends upon the differential renaturation of DNA for its effect. 9. G-banding is more delicate and relatively mild conditions allow staining of both C-and G-bands. To obtain only C-bands the chromosome must be treated more harshly to disrupt or destroy the G-bands. 10. DNA-non histone protein interactions probably play an important role in the production of both C-and G-banding.

Rotenone, a mitochondrial complex 1 inhibitor, causes oxidative damage via production of reactive oxygen species. We examined the pathophysiology of neuronal and glial cells of the nigrostriatal pathway following unilateral infusion of varying doses of rotenone into the substantia nigra or medial forebrain bundle of adult male Sprague-Dawley rats, sacrificed 14 and 60 days after infusion. Immunofluorescence techniques were used to qualitatively and quantitatively assay dopaminergic neurons, their projections, glial cells, synapses, and oxidative stress. Rotenone infusion into the substantia nigra at all concentrations caused extensive damage and tissue necrosis, therefore of limited relevance for producing a Parkinson disease model. Infusion of 0.5 μg of rotenone targeting the medial forebrain bundle induced oxidative stress in dopaminergic neurons causing ongoing cell stress as defined by an elevation of stress granule and oxidative stress markers. This treatment resulted in the loss of tyrosine hydroxylase immunoreactive cells in the substantia nigra (p ≤ 0.01) and loss of tyrosine hydroxylase immunoreactive nerve fibres and synaptic specialisations in the striatum (p ≤ 0.01). The infusion of 0.5 μg of rotenone also caused an increase in astrocytes and microglial cells in the substantia nigra in comparison to control (p ≤ 0.01). We examined the time-dependent reduction of tyrosine hydroxylase-positive nerve fibres and cell bodies in the striatum and substantia nigra respectively, with a progressive reduction evident 60 days after infusion (p ≤ 0.01, p ≤ 0.05). Dopaminergic axons exposed to low-dose rotenone undergo oxidative stress, with a resultant ongoing loss of dopaminergic neurons, providing an animal model relevant to Parkinson disease.

We have established primary cell culture of the marine demosponge Dysidea avara and Suberites domuncula . Microbial contamination was controlled by the use of a pool of antibiotics confirming the goodness of this procedure. Effect of pH, temperature and light was studied to establish the better growth conditions. The comparison of lipid composition of sponge and cells suggested a series of experiments to optimise the medium. A glucose dose-dependent experiment showed that the ideal glucose concentration is 1 g l (1 . Supplementing the medium with unsaturated fatty acid and retinol, no promotion of growth was observed, but the compounds were totally metabolised by cells. Increments from 70 to 160% in the number of cells were observed, supplementing the medium with different concentration of cholesterol. These results suggest that the analysis of the chemical composition of sponge and cells give indication on the composition of the nutrient media. #

Most in vivo body composition methods rely on assumptions that may vary among different population groups as well as within the same population group. The assumptions are based on in vitro body composition (carcass) analyses. The majority of body composition studies were performed on Caucasians and much of the information on validity methods and assumptions were available only for this ethnic group. It is assumed that these assumptions are also valid for other ethnic groups. However, if apparent differences across ethnic groups in body composition 'constants' and body composition 'rules' are not taken into account, biased information on body composition will be the result. This in turn may lead to misclassification of obesity or underweight at an individual as well as a population level. There is a need for more cross-ethnic population studies on body composition. Those studies should be carried out carefully, with adequate methodology and standardization for the obtained information to be valuable.

Raloxifene (RAL) and alendronate (ALN) improve the biomechanical properties of bone by different mechanisms. The goal here was to investigate the effects of combination treatment of RAL and ALN on the biomechanical properties of vertebral bone. Six-month-old Sprague-Dawley rats (n = 80) were randomized into five experimental groups (sham, OVX, OVX + RAL, OVX + ALN, and OVX + RAL + ALN; n = 16/group). Following euthanization, structural and derived material biomechanical properties of vertebral bodies were assessed. Density and dynamic histomorphometric measurements were made on cancellous bone. The results demonstrate that the structural biomechanical properties of vertebral bone are improved with the combination treatment. Stiffness and ultimate load of the OVX + RAL and OVX + ALN groups were significantly lower than those of sham animals, but the combination treatment with RAL + ALN was not significantly different from sham. Furthermore, the OVX + RAL + ALN group was the only agent-treated group in which the ultimate load was significantly higher than that in OVX animals (p < .05). Cancellous bone fractional volume (BV/TVcanc) and bone mineral density (aBMD) also were improved with the combination treatment. BV/TVcanc of the OVX + RAL + ALN group was 6.7% and 8.7% greater than that of the OVX + RAL (p < .05) and OVX + ALN (p < .05) groups, respectively. Areal BMD of the OVX + RAL or OVX + ALN groups was not significantly different from that in OVX animals, but the value in animals undergoing combination treatment was significantly higher than that in OVX or OVX + RAL animals alone and not significantly different from that in sham-operated animals. Turnover rates of both the RAL + ALN and ALN alone groups were lower than in the RAL-treated alone group (p < .05). We conclude that the combination treatment of raloxifene and alendronate has beneficial effects on bone volume, resulting in improvement in the structural properties of vertebral bone. © 2011 American Society for Bone and Mineral Research.

Background: Hyperekplexia is caused by defective glycinergic neurotransmission. Results: A dominant negative glycine transporter-2 mutant is trapped in a calnexin-bound state and retains wild type GlyT2 in the endoplasmic reticulum. Conclusion: Chemical chaperones rescue the folding defect of the mutant and overcome its dominant negative effect. Significance: This opens the way to revert the dominant negative effect exerted by the mutant associated with hyperekplexia in neurons.

Dimer structure and liquid structure of fatty acids in their binary mixtures such as decanoic acid (DA)/octadecanoic acid (SA) and DA/dodecanoic acid (LA) were studied through the measurements of self-diffusion coefficient (D), differential scanning calorimetry (DSC), density and viscosity. The obtained phase diagrams showed that DA and SA form a eutectic in the solid state but partly a solid solution in the SA-rich region; DA and LA form an incongruent-melting compound which forms a eutectic with DA. In the liquid mixture of DA and SA, the D of DA is larger than that of SA over the entire range of compositions and tends to approach the D of SA with increasing SA-mole fraction; the D of DA in the DA/LA system is also larger than that of LA especially in the LA-poor region and steeply approaches that of LA with increasing LA-mole fraction. These D values and phase diagrams were compared with those for the binary mixtures of n-alkanes (C 14 /C 20 , C 19 /C 20 and C 20 /C 24); it is concluded that the two kinds of fatty acids always form their individual homodimers in their liquid mixtures regardless of their compositions and temperatures.

Disc centrifuge photosedimentometry (DCP) with fluids of different densities is used to simultaneously determine the particle size and effective density of spherical silica particles. Incorporation of a calibrated infrared pyrometer into a DCP instrument is shown to enhance the measurement capability of the DCP technique by correcting for the temperature dependence of the spin fluid's density and viscosity. Advantages of absolute DCP determinations for size and density analysis relative to standardized DCP measurements include the elimination of instrument standardization with a particle of known density and measurements or estimation of the effective particle density. The reliability of diameter determinations provided by absolute DCP was confirmed using silica particles with nominal diameters ranging from 250 to 700 nm by comparison of these analyses with a diameter determination by transmission electron microscopy for silica particle size standards. Effective densities determined by absolute DCP for the silica particles ranged from 2.02 to 2.34 g/cm 3 . These findings indicate that the silica particles have little or no porosity. The reported characterization of colloidal silica using absolute DCP suggests applicability of the technique to a variety of particle types including colloidal materials other than silica, core−shell particles, compositionally heterogeneous mixtures of nanoparticles, and irregularly shaped, structured colloids.

To develop a predictive, experimentally verified computational fluid dynamic model for gas–liquid–solid flow, a 3-D transient computer code for the coupled Navier–Stokes equations for each phase was developed. The principal input into the model is the viscosity of the particulate phase, which was determined from a measurement of the random kinetic energy of the 800-micron glass beads and a Brookfield viscometer. The computed time-averaged particle velocities and concentrations agree with PIV measurements of velocities and concentrations, obtained using a combination of gamma-ray and X-ray densitometry, in a slurry bubble column, operated in the bubbly-coalesced fluidization regime with a continuous flow of water. Both the experiment and simulation show a downflow of particles in the center of the column, and an upflow near the walls, and a nearly uniform particle concentration. Normal and shear Reynolds stresses were constructed from the computed instantaneous particle velocities. The PIV measurement and the simulation produced similar nearly flat horizontal profiles of turbulent kinetic energy of particles.

A simple, accurate, and economical method has been proposed to measure formaldehyde in aqueous samples. The method is based on quantification of classical chromotropic acid-formaldehyde violet spots developed on TLC. Different parameters such as concentration of chromotropic and sulfuric acid, time of heating and order of application of reagents have been studied to find out the optimum working procedure. Spots have been quantified by scanning the spotted TLC and analyzing the image in computer with Visual Basic 6.0 based graphic application. The study consisted of developing an appropriate calibration line, analyzing artificial and real samples, and comparing the new method with a standard spectrophotometric method (NIOSH Method-3500, 1994). It has been concluded that the present method had the capability for measuring formaldehyde in aqueous samples at trace level with high precision and accuracy, particularly when dealing with turbid and small volume samples where the standard method failed.

An HPTLC densitometric method for the simultaneous determination of cinnamaldehyde and eugenol as well as trace amounts of piperine in pepper-contaminated cinnamon was developed. The applicability of the method was tested with cinnamon bark powder adulterated with pepper powder, cinnamon oil, clove powder, clove oil and a commercial preparation containing cinnamaldehyde and eugenol. The method was validated for specificity, precision, accuracy and robustness. The method was found to be precise for different concentrations of cinnamaldehyde, eugenol and piperine. The accuracy of the method was checked by conducting a recovery study at three different levels. The linearity was found to be in the ranges 52.54-735.56, 533.2-8531.2 and 50-300 ng/spot, respectively, with correlation coefficients of 0.9985 +/- 0.04, 0.9982 +/- 0.06 and 0.9937 +/- 0.11 for cinnamaldehyde, eugenol and piperine.

Ivy (Hedera helix L., Araliaceae), is an evergreen medicinal and ornamental plant. Depending on leaf polymorphism different shaped ivy leaves were extracted and subsequently analyzed by reversed-phase high performance liquid chromatography (RP-HPLC). Quantitative determination of its most prominent saponins hederacoside C (1) and alpha-hederin (2) from different ivy leaf extracts were detected, validated and optimized for quick profiling. The linearity of response, repeatability and reproducibility of the applied RP-HPLC method are reported.

A sensitive, selective, precise and stability-indicating thin-layer chromatographic (TLC) method was developed and validated for the analysis of noscapine, both as a bulk drug and in its formulation. The method employed TLC aluminium plates precoated with silica gel 60F-254 as the stationary phase. The solvent system consisted of chloroform-methanol (10:0.5 v/v). Densitometric analysis of noscapine and its degradation products was carried out in the absorbance mode at 254 nm. This system was found to give compact symmetrical spots for noscapine (R(f) value 0.85 +/- 0.04). Noscapine was subjected to acid and alkali hydrolysis, oxidation and photo degradation. The drug undergoes photo degradation and also degrades under acidic and basic conditions. The prepared degradation products were identified and verified through infrared (IR) and mass spectral analyses. The degraded products were also well resolved from the pure drug with significantly different R(f) values and they were quantitatively determined. The method was validated for linearity, precision, robustness, limit of detection (LOD), limit of quantitation (LOQ), specificity and accuracy. Linearity was found to be in the 1.0-10.0 microg, 0.4-3.2 microg, 1.0-9.0 microg and 0.5-5.0 microg/band ranges for noscapine, cotarnine, meconine and opionic acid, respectively. The polynomial regression analysis for the calibration plots showed a good polynomial relationship with r(2) of 0.9998, 9989, 9996 and 0.9997 for noscapine and its three degradation products, cotarnine, meconine and opionic acid, respectively. Statistical analysis proves that the method is repeatable and specific for the estimation of noscapine. As this approach could effectively separate the drug from its degradation products it can be employed as a stability-indicating method in Quality Control laboratories.

Phospholipids, sphingolipids, and sterols are the major lipid components of the plasma membranes of eukaryotic cells. Because these three lipid classes occur naturally as enantiomerically pure compounds, enantiospecific lipid-lipid and lipidsterol interactions could in principle occur in the lipid bilayers of eukaryotic plasma membranes. Although previous biophysical studies of phospholipid and phospholipid-sterol model membrane systems have consistently failed to observe such enantiomerically selective interactions, a recent monolayer study of the interactions of natural and enantiomeric cholesterol with egg sphingomyelin has apparently revealed the existence of enantiospecific sterol-sphingolipid interactions. To determine whether enantiospecific sterol-sphingolipid interactions also occur in more biologically relevant lipid bilayer systems, differential scanning calorimetric, x-ray diffraction, and neutral buoyant-density measurements were utilized to study the effects of natural and enantiomeric cholesterol on the thermotropic phase behavior and structure of egg sphingomyelin bilayers. The calorimetry experiments show that natural and enantiomeric cholesterol have essentially identical effects on the temperature, enthalpy, and cooperativity of the gel/liquid-crystalline phase transition of egg sphingomyelin bilayers within the limits of experimental error. As well, the x-ray diffraction and neutral buoyancy experiments indicate that bilayers formed from mixtures of natural or enantiomeric cholesterol and egg sphingomyelin have, within experimental uncertainty, the same structure and mass density. We thus conclude that significant enantioselective cholesterol-sphingolipid interactions do not occur in this lipid bilayer model membrane system.

A binary mixture of terbinafine hydrochloride and triamcinolone acetonide was determined by three different methods. The first one concerned with determination of both drugs using first derivative (D 1 ) spectrophotometric technique at 297 and 274 nm over concentration ranges of 5 -30 and 4 -24 mg ml − 1 , with mean percentage accuracies 99.90 9 0.67 and 100.25 90.49, respectively. The second method depends on ratio-spectra 1st derivative (RSD 1 ) spectrophotometry at 298 and 248 nm over the same concentration ranges with mean percentage accuracies 100.229 0.51 and 99.93 90.56, respectively. The spectrodensitometric analysis provides a rapid and precise method for the separation and quantitation of both terbinafine hydrochloride and triamcinolone acetonide. The method depends on the quantitative densitometric evaluation of thin layer chromatogram of terbinafine hydrochloride and triamcinolone acetonide at 283 and 238 nm over concentration ranges of 5 -25 and 2.5-22.5 mg spot − 1 , with mean percentage accuracies 100.66 9 0.51 and 100.27 9 0.73, respectively. The suggested procedures were checked using laboratory prepared mixtures and were successfully applied for the analysis of their pharmaceutical preparations. The three methods retained their accuracy and precision when applying the standard addition technique. The results obtained by applying the proposed methods were statistically analysed and compared with those obtained by a reported method.

The authors compared image quality and stability with a dry laser imager versus a conventional wet laser imager. Hard copies of 56 magnetic resonance imaging and computed tomographic studies were analyzed for gray-scale distribution and temperature stability. Results with the dry laser imager did not reach the quality of results with a wet laser imager, but the performance and ecologic criteria were sufficient to make use of this technique advantageous.

Synopsis. Alcian Blue stains much more slowly than other basic dyes, and differential staining by the dye is greatly influenced by differences in the rate of staining of various basophilic components. Epithelial mucin stains most rapidly, followed by mast cell granules, pericapsular cartilage matrix, interstitial cartilage matrix, nuclei and cytoplasmic chromidial substance (presumably RNA), in that order. Sites containing nucleic acid stain intensely under some conditions, e.g. after some days in Alcian Blue at pH 4 and room temperature and, therefore, do not lack affinity for the dye. Nucleic acids are not, however, in general easily stained with Alcian Blue, being extremely slow-staining and also being easily leached from the section by hot or acidic solutions. Not only do most substrates fail to reach a plateau value of dye uptake after 'normal', relatively short, staining times (e.g. some hours), but the reversibility of staining by Alcian Blue is markedly affected by the duration of staining. The dye is largely or completely irremovable from most substrates after any except the shortest staining times, but cartilage matrix and mast cell granules are exceptional in that a good deal of dye is removable from these substrates by I.O M MgCI~, even after prolonged staining. Raising the temperature of, or adding urea to, the dyebath decreases dye aggregation and increases the uptake of Atcian Blue, particularly by relatively slow-staining substrates. Mast cell granules stained with hot dye under some conditions (e.g.o.05 % dye, pH 4, 56~ 18 hr), but not with cold dye (e.g. 7 days at 4~ unless pre-treated with hot buffer. The aggregation of Alcian Blue in solution, as assessed by changes in the absorption spectrum, is markedly affected by dye concentration, dyebath temperature, additives such as salt or urea, and also by the age of the solution, the dye being notably unstable under some conditions. The 'critical electrolyte concentration' method of Alcian Blue staining, for the characterization of tissue polyanions, theoretically requires staining to be carried to a true (reversible) equilibrium. The present findings throw doubt on the validity of the method.

We report the optimization of a sensitive, selective and robust derivatization method using 4-dimethylaminocinnamaldehyde (DMACA) for densitometric determination of (+)-catechin and (−)epicatechin. The separation of these compounds was achieved by thin-layer chromatography (TLC) on cellulose plates developed with water. With DMACA in HCl, both compounds gave blue bands, while under the same conditions, vanillin produced a fast fading red coloration of bands. Quantitation at 655 nm showed that for both compounds the calibration curve was linear from 2 to 12 ng and polynomial from 2 to 30 ng, and the repeatability of chromatography of 20 ng was 3.5% (RSD, n = 6). The visible limit of detection of both standards was 1 ng, but the densitometric limit of detection was lower (0.2 ng). The optimized DMACA reagent is superior to the more frequently used vanillin reagent and is applicable also for determination of mixtures containing other catechins ((−)-catechin, (−)-epicatechin gallate, (−)-epigallocatechin gallate, procyanidin A2, procyanidin B1 and procyanidin B2).

Biogenic amines are small-molecular-weight organic bases that can be encountered in all fermented foods, including wine. Ingestion of wine containing biogenic amines, and especially histamine, can result in health nuisances. HPLC is the analytical technique most often employed in the determination of biogenic amines in wine but HPLC-based methods are expensive and time-consuming. A new method, based upon amine dansylation and TLC/densitometry, was developed and validated. This allowed for the determination of histamine, tyramine, putrescine and cadaverine in wine at concentrations between 1 and 20 mg/L. Analytical performances adequately complied with the needs of routine wine analysis, moreover the method was high-throughput and inexpensive. A simpler, semi-quantitative version of the method, based on visual evaluation of spot intensity, was also developed.

Air filled porosity (AFP) appears as the best measure to determine the available porosity in a composting material or, in general, in an organic matrix. Several methodologies, including theoretical and empirical approaches have been developed to estimate AFP. Among them, air pycnometry has been considered the most suitable and accurate technique to obtain reliable measures of AFP. In this review, the published methodologies to determine AFP by air pycnometry are explained in detail, and the main advantages and disadvantages of such methodologies are discussed. Also, a massive sampling of several organic wastes and mixtures intended for composting has been characterized by air pycnometry, and the theoretical and empirical correlations proposed in literature are compared in terms of accuracy in AFP measurement. Results obtained show that some theoretical correlations are suitable for estimating AFP in the majority of organic wastes studied. However, some waste samples need an experimental determination to obtain a realistic value of AFP.

The adulteration of herbal supplements is of growing importance, especially when they contain undeclared compounds like sibutramine that are unsafe drugs. Sibutramine was withdrawn from US and European markets in 2010. In this study, an HPTLC-UV densitometric method was developed for the quantification of sibutramine in herbal diet foods. Sample extracts were directly applied onto HPTLC silica gel plates and separated with a mobile phase made of a toluene-methanol mixture. Sibutramine was quantified at 225 nm and its unequivocal identification was confirmed by MS using a TLC-MS interface. During two surveys, 52 weight loss supplements obtained via the Internet were screened. Half of those were adulterated with sibutramine at amounts reaching up to 35 mg per capsule. The results of this validated HPTLC method were compared with those obtained by HPLC-UV and HPLC-MS/MS. The results were not significantly different with the three methods.

The investigation of drug penetration into the stratum corneum (SC) by tape-stripping requires an accurate measure of the amount of SC on each tape-strip in order to determine the depth inside the SC. This study applies infrared densitometry (IR-D) to in vitro tape-stripping using the novel Squame Scan 850A. The device had recently been shown to provide accurate measurements of the SC depth for tapestripping in vivo. Furthermore, the suitability of IR-D for determining the endpoint of tape-stripping, i.e. complete SC removal, was tested. The SC depth was computed from the IR-D data of sequential tape-strips and compared to the results of a protein assay as gold standard. IR-D provided accurate depth results both for freshly excised skin and for skin stored frozen for up to 3 months. In addition, the lower limit of quantification of IR-D indicates the complete removal of the SC (less than 5% of the total SC remaining) and can be used for adjusting the number of tapes applied in situ. Therefore, IR-D is an accurate, fast and non-destructive method for SC depth determination.

This study reports on the development and evaluation of a protocol for testing DEXA systems, which can be incorporated into a routine medical physics/engineering service. Methodologies are reported for (1) scatter measurement, (2) estimation of reference dose and (3) enquiry into potential sources of overexposure. Results show that fan-beam and cone-beam systems require shielding if the walls or operator are within 1 m of the table. Patient reference dose was estimated using the dose-area product (DAP). This varied over an order of magnitude from 2 to 36 mGy cm 2 in the range of systems studied. The inquiry into potential sources of overexposure revealed some weaknesses in current practise including a design which prevents the inclusion of DAP metres; beam non-uniformity; incorrect specification of patient dose and the risk of overexposure when tube operates during patient positioning.

A simple and reliable assay for diazepam, nitrazepam and flunitrazepam in tablets by high-performance liquid chromatography (HPLC) and thin-layer chromatography (TLC) Á/densitometry is described. A quantity of a ground tablet mass, equal to the average weight of one tablet was sonicated in MeOH, mixed with appropriate internal standard, filtered and either injected directly into the liquid chromatograph, or after evaporation and reconstitution of an aliquot of the extract, was spotted on a silica gel thin-layer plate. A variable UV detector, operated at 254 nm was employed in both procedures. A C18, reversed phase 7 mm column was used for HPLC analysis; the mobile phase was a 1:1 (v/v) mixture of MeOH (40 8C) and 0.01 M phosphate buffer (pH 7, 80 8C). The TLC plate was developed in an unsaturated chromatographic chamber containing 100 ml chloroform Á/acetone (9:1); at room temperature, the mobile phase was allowed to travel 15 cm. The percentage of the active ingredient content of each tablet obtained by both procedures, was in the range of the stated amount except for one brand of diazepam tablets which contained Â/23% less active ingredient than the minimum prescribed amount. The TLC densitometry, although yields slightly higher values than the HPLC method, is preferred due to its simplicity, ease and low cost. #

In this work, high performance thin layer liquid chromatography (HTPLC) is applied to the determination of sugars in fast pyrolysis liquids (bio-oil) and fractions thereof. The proposed procedure allows the separation of anhydrosugar levoglucosan and cellobiosan, as well as glucose, arabinose, xylose and cellobiose. Pre-treatment and derivatization of samples are not necessary and volatile compounds present in bio-oil do not interfere with sugar analysis. The detrimental effect of the complex bio-oil matrix on columns and detector lifetime is avoided by using disposable HTPLC plates. Prior screening of glucose, present especially in aged and aqueous bio-oil fractions, is required to quantify cellobiosan without interference. Concentrations of levoglucosan and cellobiosan in bio-oil samples obtained from Pinus radiata sawdust were ranged between 1.27-2.26% and 0.98-1.96% respectively, while a bio-oil sample obtained from native wood contained a higher levoglucosan concentration.

Applications using radiotracers and quantitative film autoradiography are increasing dramatically in the neurosciences. Microcomputer-based image analyzing systems with video input have been developed to provide rapid quantification of autoradiographic images on relatively inexpensive systems. However, there has been some question as to whether such systems can reliably produce high levels of densitometric accuracy, especially when compared to mechanical scanners which are standard in research requiring extreme fidelity of measurement. We report methods and results from tests done to determine the analytical and functional accuracy of the Drexel Unix-based Microcomputer image Analysis System (DUMAS), which is a video densitometric system designed to provide quantitative data from autoradiograms. Analytic accuracy was determined by measuring photometric uniformity, the optical density transfer function, temporal stability, geometric uniformity, and flare. In addition, data are provided on the resolution of the system at several magnifications. Functional accuracy, the accuracy of the estimates of mean isotope concentrations in diverse neural structures, was determined by comparing the results obtained on the DUMAS system with the results from analyzing the same [14C]2-deoxyglucose images with two different Optronics P1000 systems. Our results show that, provided care is taken in the choice of a camera and a light source, the analytic accuracy of videodensitometry is high. Its functional accuracy is also high in that measurements of radioisotope concentrations in diverse neural structures made on the DUMAS system agree closely with the measurements from a properly adjusted Optronics P1000 system. The rapidity and economy of videodensitometry is not, therefore, obtained at the sacrifice of densitometric accuracy. Given adequately tested hardware and provided that suitable checks on instrument calibration and adjustment are made, the errors in autoradiographic quantification due to the image analyzing system itself are minor in comparison to other sources of error, including, as we show. variations in the user's delineation of the boundaries of neural structures.

In vitro studies with fetal mouse long bone rudiments have shown that trtiodothyronine (T3) stimulates bone resorption at high concentrations and inhibits it at low concentrations. To examine whether similar biphasic effects of thyroid hormones are observed in vivo, eight-week old female Swiss-Webster mice (n=6-6 per each group) were made either mildly thyrotoxic by continuous subcutaneous infusion of T3 (3 ug/lOO g BW/day) using an osmotic mini pump or severely thyrotoxic by the addition of 2 ug/ml thyroxine (T4) to the drinking water. The duration of treatment was 3 weeks and all animals were double labelled in vivo with oxytetracycline and calcein. Blood was obtained by cardiac puncture before sacrifice for biochemical evaluation. Femora and tibiae were dissected for ash weight measurements and histomorphometric analysis, respectively. In TB-treated mice serum T3 concentrations were about 2.5fold higher than in control group (2.45 f 0.41 vs. 1.04 rt 0.07 nglml , mean f SEM ), and serum T4 was suppressed. Mean femoral length was significantly (p x 0.05) higher than in controls and there was no difference in ash weight/bone length between the two groups. In T4-treated mice serum T3 concentrations were 5.34 f 0.46 nglml (mean f SEM) and serum T4 was about 3fold higher than in the control. There was no difference in femoral length between TGtreated and control groups, however, ash weight/bone length was significantly (p < 0.05) lower in T6treated mice (1.76 f 0.07 vs. 2.11 f 0.06 mglmm). We conclude that the effects of thyroid hormone on the skeleton are dose-dependent, low concentrations stimulate bone growth whereas high concentrations increase bone resorption and decrease bone mass. Exercise has been proposed as a possible way to prevent the bone loss associated with aging. This study examines the effect of exercise on trabecular bone formation and resorption by histomorphometry and metaphyseal bone density by Dual Energy X-ray Densitometry (DEXA). Forty female rats at 14-months of age were divided into exercised (EX) and control (CON) groups. Exercise consisted of running on a flat-bed treadmill, 17 mfmin., 1 hrfday and 5 days/week. Metaphyseal bone density of the tibia of each rat was measured by DEXA at basal, 9 and 16 week periods. Histomorphometric analysis showed that 9 and 16 weeks of exercise suppressed trabecular bone eroded perimeter (30%; 14%, PcO.05) and the ratio of eroded to labeled perimeter (33%; 28%, PcO.05) respectively. A significant increase in the bone formation rate was apparent only after 16 weeks of exercise (mean+S.E. of EX 5.17kO.48 vs CON 3.6520.37 urn/day, P=O.O27). The trabecular area increased and the bone architecture (increased improved trabecular number and decreased trabecular separation) but not significantly to the CON at each time point. The slope of the metaphyseal bone density of each rat was higher in the EX than in the CON group (EX 1.744kO.388 vs CON 0.749kO.345 mg/cm /week, P=O.037).

A thin-layer chromatographic (TLC) method is developed to analyze the total saponin content, also referred to as the aescin content, in a herbal medicinal product (HMP) containing two dry extracts in capsules. The capsules contain 250 mg of Aesculus hippocastanum dry extract, 120 mg of Vitis vinifera dry extract and 50 mg of excipients. After a purification step using C 18 solid phase extraction (SPE) cartridges, the samples are analyzed on a silica-gel HPTLC plate with the upper layer of a mixture of acetic acid/water/butanol (10/40/50 v/v/v) as the mobile phase. Spots are visualized by spraying with anisaldehyde reagent and heating the plate for 5-10 min (100-105 • C) and measured at a wavelength of 535 nm. This method, applicable for the quality control and stability investigation of both the Aesculus dry extract and HMP capsules thereof containing Vitis dry extract in combination with the Aesculus dry extract, is validated according to the International Conference on Harmonization (ICH) guidelines. The proposed assay method is specific for aescin in the presence of Vitis dry extract and formulation excipients. Analysis of stressed samples in forced degradation tests proves the method to be applicable for stability evaluation. The standard aescin curve is linear (r > 0.99) over a concentration range of 0.16-0.80 g/spot. Recovery from the HMP capsules is statistically equal to 100%. The precision of the method with respect to time and concentration is acceptable, with relative standard deviation (RSD) values of 1.28 and 1.49%, respectively.

Male idiopathic osteoporosis (MIO) is a metabolic bone disease that is characterized by low bone mass, microstructural alterations, and increased fracture risk in otherwise healthy men. Although the detailed pathophysiology of MIO has yet to be clarified, evidence increasingly suggests an osteoblastic defect as the underlying cause. In this study we tested the hypothesis that the expression profile of certain osteoblastic or osteoblast-related genes (ie, WNT10B, RUNX2, Osterix, Osteocalcin, SOST, RANKL, and OPG) is different in iliac crest biopsies of MIO patients when compared with healthy controls. Furthermore, we investigated the relation of local gene expression characteristics with histomorphometric, microstructural, and clinical features. Following written informed consent and diligent clinical patient characterization, iliac crest biopsies were performed in nine men. While RNA extraction, reverse-transcription, and real-time polymerase chain reactions (PCRs) were performed on one biopsy, a second biopsy of each patient was submitted for histomorphometry and micro-computed tomography (mCT). Age-matched bone samples from forensic autopsies served as controls. MIO patients displayed significantly reduced WNT10B, RUNX2, RANKL, and SOST expression. Performing mCT for the first time in MIO biopsies, we found significant decreases in trabecular number and connectivity density. Trabecular separation was increased significantly, but trabecular thickness was similar in both groups. Histomorphometry revealed decreased BV/TV and osteoid volume and fewer osteoclasts in MIO. By providing evidence for reduced local WNT10B, RUNX2, and RANKL gene expression and histomorphometric low turnover, our data support the osteoblast dysfunction model discussed for MIO. Further, MIO seems to lead to a different microstructural pathology than age-related bone loss. ß

Simple methods for HPTLC peak purity assessment and identification of the HPTLC peaks were presented. The spectrodensitograms -selected at different time intervals across the elution time of the HPTLC peak -were extracted and digital algorithms for manipulating the data were carried out in the wavelength domain. Three different methods were developed for testing the HPTLC peak purity using the mathematically transformed data of the spectrodensitograms. These included the method of relative absorption, the method of log A versus the wavelength plots and the derivative (first, second, third and fourth) method. The identification of the HPTLC peaks was based on the use of the derivative profile of the spectrodensitogram and the derivative ratios as fingerprints for the compounds. The wavelengths of absorbance and derivative (first, second, third and fourth) optima of the extracted spectrodensitograms were allocated. The data were compared with those obtained using the corresponding reference standard. The validity of the proposed methods was performed by chromatography of a mixture containing mebendazole and methylparaben as a model versus the winCATS ® spectral correlation method as a reference method. The study indicated that the proposed concept is a reliable non-confusing valuable tool for testing the purity and identity of the HPTLC peaks as the results are easily and rigorously interpreted.

The avian nidopallium caudolaterale is a multimodal area in the caudal telencephalon that is apparently not homologous to the mammalian prefrontal cortex but serves comparable functions. Here we analyzed bindingsite densities of glutamatergic AMPA, NMDA and kainate receptors, GABAergic GABA A , muscarinic M 1 , M 2 and nicotinic (nACh) receptors, noradrenergic a 1 and a 2 , serotonergic 5-HT 1A and dopaminergic D 1 -like receptors using quantitative in vitro receptor autoradiography. We compared the receptor architecture of the pigeons' nidopallial structures, in particular the NCL, with cortical areas Fr2 and Cg1 in rats and prefrontal area BA10 in humans. Our results confirmed that the relative ratios of multiple receptor densities across different nidopallial structures (their ''receptor fingerprints'') were very similar in shape; however, the absolute binding densities (the ''size'' of the fingerprints) differed significantly. This finding enables a delineation of the avian NCL from surrounding structures and a further parcellation into a medial and a lateral part as revealed by differences in densities of nACh, M 2 , kainate, and 5-HT 1A receptors. Comparisons of the NCL with the rat and human frontal structures showed differences in the receptor distribution, particularly of the glutamate receptors, but also revealed highly conserved features like the identical densities of GABA A , M 2 , nACh and D 1 -like receptors. Assuming a convergent evolution of avian and mammalian prefrontal areas, our results support the hypothesis that specific neurochemical traits provide the molecular background for higher order processes such as executive functions. The differences in glutamate receptor distributions may reflect species-specific adaptations.

This study determined the chemical composition, pH, and radiopacity of mineral trioxide aggregate (MTA), and also compared the setting time, compressive strength, and solubility of this material with those of amalgam, Super-EBA, and Intermediate Restorative Material (IRM). X-ray energy dispersive spectrometer in conjunction with the scanning electron microscope were used to determine the composition of MTA, and the pH value of MTA was assessed with a pH meter using a temperature-compensated electrode. The radiopacity of MTA was determined according to the method described by the International Organization for Standardization. The setting time and compressive strength of these materials were determined according to methods recommended by the British Standards Institution. The degree of solubility of the materials was assessed according to modified American Dental Association specifications. The results showed that the main molecules present in MTA are calcium and phosphorous ions. In addition, MTA has a pH of 10.2 initially, which rises to 12.5 three hours after mixing. MTA is more radiopaque than Super-EBA and IRM. Amalgam had the shortest setting time (4 min) and MTA the longest (2 h 45 rain). At 24 h MTA had the lowest compressive strength (40 MPa) among the materials, but it increased after 21 days to 67 MPa. Finally, except for IRM, none of the materials tested showed any solubility under the conditions of this study. 350 Torabinejad et al. Journal of Endodontics