Mean Pixel Intensity Research Articles

Pixel Intensity and Fractal Dimension of Periapical Lesions Visually Indiscernible in Radiographs

IntroductionThe purpose of the study was to analyze pixel intensity (PI) and fractal dimension (FD) values in radiographs of chemically created but visually undetectable periapical lesions. MethodsArtificial lesions were created by applying 70% perchloric acid to the sockets of left and right first premolars in 12 cadaver mandibles. For preparation of relatively small lesions, the acid was applied for 30 and 60 minutes. Before and after each acid application, radiographs were taken (60 kVp, 7 mA, and 1.5 mm Al equivalent filtration for 0.12 second) with storage phosphor plates. An optical bench was used to standardize projection geometry. Image plates were scanned immediately after exposure, and the acquired images were saved uncompressed in TIF format. Six observers evaluated the images by using a 5-grade scale, and the images scored as “definitely absent” by all observers were used for the calculations of PI and FD. Box-counting FDs and differences in mean PI were computed for regions of interest at the apical areas of each premolar. Repeated-measures analysis of variance, Tukey test, and Pearson correlation coefficient test were used for statistical analysis. ResultsA significant difference was found in FD values after both acid application periods (P < .05), whereas a difference in PI was detected only in images obtained after 60-minute acid application (P < .05). There was a negative correlation between FD and PI values (−0.754, P < .05). ConclusionsCalculation of FD can be a tool for the early detection of periapical lesions given the presence of baseline radiographs.

Anisotropy of Crumbs and aPKC Drives Myosin Cable Assembly during Tube Formation

SummaryThe formation of tubular structures from epithelial sheets is a key process of organ formation in all animals, but the cytoskeletal rearrangements that cause the cell shape changes that drive tubulogenesis are not well understood. Using live imaging and super-resolution microscopy to analyze the tubulogenesis of the Drosophila salivary glands, I find that an anisotropic plasma membrane distribution of the protein Crumbs, mediated by its large extracellular domain, determines the subcellular localization of a supracellular actomyosin cable in the cells at the placode border, with myosin II accumulating at edges where Crumbs is lowest. Laser ablation shows that the cable is under increased tension, implying an active involvement in the invagination process. Crumbs anisotropy leads to anisotropic distribution of aPKC, which in turn can negatively regulate Rok, thus preventing the formation of a cable where Crumbs and aPKC are localized.

X-ray fluoroscopy noise modeling for filter design

Fluoroscopy is an invaluable tool in various medical practices such as catheterization or image-guided surgery. Patient's screen for prolonged time requires substantial reduction in X-ray exposure: The limited number of photons generates relevant quantum noise. Denoising is essential to enhance fluoroscopic image quality and can be considerably improved by considering the peculiar noise characteristics. This study presents analytical models of fluoroscopic noise to express the variance of noise as a function of gray level, a practical method to estimate the parameters of the models and a possible application to improve the performance of noise filtering. Quantum noise is modeled as a Poisson distribution and results strongly signal-dependent. However, fluoroscopic devices generally apply gray-level transformations (i.e., logarithmic-mapping, gamma-correction) for image enhancement. The resulting statistical transformations of the noise were analytically derived. In addition, a characterization of the statistics of noise for fluoroscopic image differences was offered by resorting to Skellam distribution. Real fluoroscopic sequences of a simple step-phantom were acquired by a conventional fluoroscopic device and were utilized as actual noise measurements to compare with. An adaptive spatio-temporal filter based on the local conditional average of similar pixels has been proposed. The gray-level differences between the local pixel and the neighboring pixels have been assumed as measure of similarity. Filter performance was evaluated by using real fluoroscopic images of a step phantom and acquired during a pacemaker implantation. The comparison between experimental data and the analytical derivation of the relationship between noise variance and mean pixel intensity (noise-parameter models) were presented relatively to raw-images, after applying logarithmic-mapping or gamma-correction and for difference images. Results have confirmed a great agreement (adjusted R-squared values > 0.8). Clipping effects of real sensors were also addressed. A fine image restoration has been obtained by using a conditioned spatio-temporal average filter based on the noise statistics previously estimated. Fluoroscopic noise modeling is useful to design effective procedures for noise estimation and image filtering. In particular, filter performance analysis has showed that the knowledge of the noise model and the accurate estimate of noise characteristics can significantly improve the image restoration, especially for edge preserving. Fluoroscopic image enhancement can support further X-ray exposure reduction, medical image analysis and automated object identification (i.e., surgery tools, anatomical structures).

Identifying tropical Ecuadorian Andean trees from inter‐crown pixel distributions in hyperspatial aerial imagery

AbstractQuestionIdentification of tropical tree species from low‐cost, very high‐resolution (VHR) proximal canopy remote sensing imagery has great potential for improving our understanding of tropical forest ecology. We investigated whether inter‐crown pixel information from VHR imagery could be used for taxonomic identification of trees and characterization of successional stages of tropical Andean mountain forest.LocationSanta Lucia cloud forest reserve, NW Ecuadorian Andes.MethodsWe gathered digital camera imagery (0.05‐m spatial resolution), using a remote‐controlled helicopter platform, from primary and secondary forest and identified visible crowns to species before extracting digital crown samples (2‐m radius). Using an object‐based approach, histogram descriptors and diversity metrics of pixel intensity in red, green and blue (RGB) bands were calculated for crowns, and patterns in similarity explored using ordination. Predictive models were developed and validated using four decision tree models (CHIAD, Exhaustive CHIAD, CRT and QUEST).ResultsAerial imagery represented 54% of families, 53% of genera and 56% of species sampled from the ground. Ordination (redundancy analysis) confirmed that inherent continuities, based on crown metrics, correlated with traditional species, genus and family groupings (P &lt; 0.05). Data were best described by histogram means in the green band. The best predictive model (CRT) generated a 47% probability of correct species identification for 41 species – with similar success at genus and family level. Predictive ability was highly species‐specific, ranging from zero for some taxa to 93% for Cecropia gabrielis Cuatrec.ConclusionsFrom the crown metrics tested, we found the mean pixel intensity in the green band was most effective in predicting species and species grouping of tropical mountain trees. This metric integrates species‐specific differences in leaf density of crowns and reflectance in the green waveband. High predictive success for indicators of primary (Cornus peruviana J.F. Macbr.) and secondary forest (Cecropia gabrielis Cuatrec.) shows that VHR imagery can be used to identify species from pixel information to provide ecological information on successional status. Further research is needed to develop pattern and textural metrics specifically for hyperspatial digital imagery to identify tree species from crown imagery in diverse tropical forests.

Narrow band imaging of squamous cell carcinoma tumors using topically delivered anti‐EGFR antibody conjugated gold nanorods

Nanoparticles have recently gained interest as exogenous contrast agents in a variety of biomedical applications related to cancer detection and treatment. The objective of this study was to determine the potential of topically administered antibody conjugated gold nanorods (GNRs) for imaging squamous cell carcinomas (SCCs) of the skin using near-infrared narrowband imaging (NBI). Near-infrared (NIR) NBI images narrow wavelength bands to enhance contrast from plasmonic particles in a wide field portable and noncontact device that is clinically compatible for real-time tumor imaging and tumor margin demarcation. We conjugated GNRs to Cetuximab, a clinically approved humanized antibody that targets the epidermal growth factor receptor (EGFR), which is overexpressed on the surface of many tumor cells, especially SCCs. We excised subcutaneous xenografts of SCCs (A431) from Swiss nu/nu mice and divided the tumors into two groups: (1) the targeted group (Cetuximab conjugated GNRs) and (2) the control group (polyethylene glycol-conjugated GNRs). After topical application of particles and incubation for 30 minutes, the tumors were washed and imaged using NBI. In addition, we performed two-photon imaging to quantify the binding of EGFR targeted GNRs in tumors and their depth profile. The NBI images showed a visual increase in contrast from tumors after topical administration of targeted GNR. Targeted GNR tumors showed increased contrast compared to tumors administered with the control GNR. There was a statistically significant increase in mean pixel intensity (∼2.5×) from targeted GNR tumors (n = 6). Two-photon microscopy images of targeted GNRs confirmed their binding affinity to the EGF receptors over expressed in the A431 tumors. We have demonstrated that a topical application of gold nanorods targeted specifically to tumor growth factor receptors results in a significantly higher image contrast compared to nontargeted gold nanorods. These results demonstrate the feasibility of near-infrared NBI to image and demarcate tumor margins during surgical resection using topical administration of targeted GNR.

The Importance of a Skin Bridge in Peripheral Tissue Perfusion in Perforator Flaps

Perforator flaps are increasingly used in reconstructive surgery. However, the microvascular perfusion pattern within these flaps remains essentially unknown. In perforator flaps, the importance of preserving the skin bridge at the base is still an object of debate. The authors hypothesized that dividing the skin bridge will increase peripheral tissue perfusion in islanded perforator flaps. The abdominal panniculus in patients submitted to elective abdominoplasty was used (n = 24). Flap perfusion was measured by dynamic laser-induced fluorescence videoangiography. The fluorescent dye indocyanine green was injected intravenously before and after conversion of a perforator flap with an intact skin bridge into an islanded perforator flap. To evaluate perfusion, mean pixel intensity and mean perfusion index were calculated in a control zone and in two zones in the flap. In zone I (the most peripheral zone), surgical release of the skin bridge increased mean pixel intensity (19.1 ± 1.9 versus 24.1 ± 2.1; p < 0.001). The mean perfusion index was calculated as 7.5 ± 5.5 and 12.6 ± 6.3 before and after surgical conversion to islanded perforator flaps, respectively. In zone II (the more proximal zone), mean pixel intensity increased (from 30.8 ± 2.8 to 33.7 ± 2.3; p < 0.001) after surgical release of the skin bridge. The mean perfusion index was 18.5 ± 11.1 and 15.6 ± 6.2. In this human experimental study, conversion of a perforator flap with a skin bridge into an islanded perforator flap increases peripheral tissue perfusion. This finding provides a physiologic basis for using islanded perforator flaps, with enhanced flap mobility and length.

Ultrasound visibility of regional anesthesia catheters: an in vitro study

BackgroundUltrasound subjective visibility of in-plane needles is correlated with the intensity difference between the needle surface and the background. Regional anesthesia catheters are difficult to visualize by an ultrasound. In the present study, we investigated the ultrasound visibility of the catheters.MethodsSix catheters were placed at 0° and 30° relative to and at a depth of 1 cm below the pork phantom surface. Ultrasound images of in-plane catheters were evaluated, subjectively and objectively. Outer and inner objective visibilities were defined as the difference in the mean pixel intensity between the catheter surface and adjacent background, and between the surface and the center of the catheter, respectively. Evaluations were made based on the portion of the catheters. A P value < 0.05 was considered significant.ResultsSubjective visibility was more strongly correlated with the inner objective visibility than with the outer objective visibility at both angles. Metallic 19-gauge catheters were more subjectively visible than the non-metallic 20-gauge catheters at 30° degrees (P < 0.01). Subjective, and outer and inner objective visibility were significantly lower at 30° than at 0° (P < 0.01, P < 0.01, P = 0.02). Perifix ONE at 0° and Perifix FX at 30° were the most visible catheters (P < 0.01 for both).ConclusionsSubjective visibility of catheters can not be evaluated in the same manner as that of the needles. For the best possible visualization, we recommend selecting a catheter with a structure that enhances the dark at the center of catheter, rather than basing the catheter selection on the bore size.

Feasibility of Adenovirus-Mediated hNIS Gene Transfer and 131I Radioiodine Therapy as a Definitive Treatment for Localized Prostate Cancer

We have developed a replication-competent adenovirus (Ad5-yCD/mutTK(SR39)rep-hNIS) armed with two suicide genes and the human sodium iodide symporter (hNIS) gene. In this context, hNIS can be used as a reporter gene in conjunction with nuclear imaging and as a potentially therapeutic gene when combined with (131)I radioiodine therapy. Here, we quantified the volume and magnitude of hNIS gene expression in the human prostate following injection of a high Ad5-yCD/mutTK(SR39)rep-hNIS dose using a standardized injection algorithm, and estimated the radiation dose that would be delivered to the prostate had men been administered (131)I with curative intent. Six men with clinically localized prostate cancer received an intraprostatic injection of Ad5-yCD/mutTK(SR39)rep-hNIS under transrectal ultrasound guidance. All men received 2 × 0.5 ml deposits (5 × 10(11) vp/deposit) in each of the four base and midgland sextants and 2 × 0.25 ml deposits (2.5 × 10(11) vp/deposit) in each of the two apex sextants for a total of 12 deposits (5 × 10(12) vp) in 5 ml. On multiple days after the adenovirus injection, men were administered sodium pertechnetate (Na(99m)TcO(4)) and hNIS gene expression in the prostate was quantified by single photon emission computed tomography (SPECT). hNIS gene expression was detected in the prostate of six of six (100%) men. On average, 45% (range 18-83%) of the prostate volume was covered with gene expression. Had men been administered 200 mCi (131)I, we estimate that the mean absorbed dose to the prostate would be 7.2 ± 4.8 Gy (range 2.1-13.3 Gy), well below that needed to sterilize the prostate. We discuss the obstacles that must be overcome before adenovirus-mediated hNIS gene transfer and (131)I radioiodine therapy can be used as a definitive treatment for localized prostate cancer.

Functional Roles of a C-terminal Signaling Complex of CaV1 Channels and A-kinase Anchoring Protein 15 in Brain Neurons

Regulation of CaV1.2 channels in cardiac myocytes by the β-adrenergic pathway requires a signaling complex in which the proteolytically processed distal C-terminal domain acts as an autoinhibitor of channel activity and mediates up-regulation by the β-adrenergic receptor and PKA bound to A-kinase anchoring protein 15 (AKAP15). We examined the significance of this distal C-terminal signaling complex for CaV1.2 and CaV1.3 channels in neurons. AKAP15 co-immunoprecipitates with CaV1.2 and CaV1.3 channels. AKAP15 has overlapping localization with CaV1.2 and CaV1.3 channels in cell bodies and proximal dendrites and is closely co-localized with CaV1.2 channels in punctate clusters. The neuronal AKAP MAP2B, which also interacts with CaV1.2 and CaV1.3 channels, has complementary localization to AKAP15, suggesting different functional roles in calcium channel regulation. Studies with mice that lack the distal C-terminal domain of CaV1.2 channels (CaV1.2ΔDCT) reveal that AKAP15 interacts with neuronal CaV1.2 channels via their C terminus in vivo and is co-localized in punctate clusters of CaV1.2 channels via that interaction. CaV1.2ΔDCT neurons have reduced L-type calcium current, indicating that the distal C-terminal domain is required for normal functional expression in vivo. Deletion of the distal C-terminal domain impairs calcium-dependent signaling from CaV1.2 channels to the nucleus, as shown by reduction in phosphorylation of the cAMP response element-binding protein. Our results define AKAP signaling complexes of CaV1.2 and CaV1.3 channels in brain and reveal three previously unrecognized functional roles for the distal C terminus of neuronal CaV1.2 channels in vivo: increased functional expression, anchoring of AKAP15 and PKA, and initiation of excitation-transcription coupling.

Deletion of the Distal C Terminus of CaV1.2 Channels Leads to Loss of β-Adrenergic Regulation and Heart Failure in Vivo

L-type calcium currents conducted by CaV1.2 channels initiate excitation-contraction coupling in cardiac and vascular smooth muscle. In the heart, the distal portion of the C terminus (DCT) is proteolytically processed in vivo and serves as a noncovalently associated autoinhibitor of CaV1.2 channel activity. This autoinhibitory complex, with A-kinase anchoring protein-15 (AKAP15) bound to the DCT, is hypothesized to serve as the substrate for β-adrenergic regulation in the fight-or-flight response. Mice expressing CaV1.2 channels with the distal C terminus deleted (DCT-/-) develop cardiac hypertrophy and die prematurely after E15. Cardiac hypertrophy and survival rate were improved by drug treatments that reduce peripheral vascular resistance and hypertension, consistent with the hypothesis that CaV1.2 hyperactivity in vascular smooth muscle causes hypertension, hypertrophy, and premature death. However, in contrast to expectation, L-type Ca2+ currents in cardiac myocytes from DCT-/- mice were dramatically reduced due to decreased cell-surface expression of CaV1.2 protein, and the voltage dependence of activation and the kinetics of inactivation were altered. CaV1.2 channels in DCT-/- myocytes fail to respond to activation of adenylyl cyclase by forskolin, and the localized expression of AKAP15 is reduced. Therefore, we conclude that the DCT of CaV1.2 channels is required in vivo for normal vascular regulation, cell-surface expression of CaV1.2 channels in cardiac myocytes, and β-adrenergic stimulation of L-type Ca2+ currents in the heart.

Patronin Regulates the Microtubule Network by Protecting Microtubule Minus Ends

Tubulin assembles into microtubule polymers that have distinct plus and minus ends. Most microtubule plus ends in living cells are dynamic; the transitions between growth and shrinkage are regulated by assembly-promoting and destabilizing proteins. In contrast, minus ends are generally not dynamic, suggesting their stabilization by some unknown protein. Here, we have identified Patronin (also known as ssp4) as a protein that stabilizes microtubule minus ends in Drosophila S2 cells. In the absence of Patronin, minus ends lose subunits through the actions of the Kinesin-13 microtubule depolymerase, leading to a sparse interphase microtubule array and short, disorganized mitotic spindles. In vitro, the selective binding of purified Patronin to microtubule minus ends is sufficient to protect them against Kinesin-13-induced depolymerization. We propose that Patronin caps and stabilizes microtubule minus ends, an activity that serves a critical role in the organization of the microtubule cytoskeleton.

The TRPV4 Channel Contributes to Intercellular Junction Formation in Keratinocytes

Transient receptor potential vanilloid 4 (TRPV4) channel is a physiological sensor for hypo-osmolarity, mechanical deformation, and warm temperature. The channel activation leads to various cellular effects involving Ca(2+) dynamics. We found that TRPV4 interacts with beta-catenin, a crucial component linking adherens junctions and the actin cytoskeleton, thereby enhancing cell-cell junction development and formation of the tight barrier between skin keratinocytes. TRPV4-deficient mice displayed impairment of the intercellular junction-dependent barrier function in the skin. In TRPV4-deficient keratinocytes, extracellular Ca(2+)-induced actin rearrangement and stratification were delayed following significant reduction in cytosolic Ca(2+) increase and small GTPase Rho activation. TRPV4 protein located where the cell-cell junctions are formed, and the channel deficiency caused abnormal cell-cell junction structures, resulting in higher intercellular permeability in vitro. Our results suggest a novel role for TRPV4 in the development and maturation of cell-cell junctions in epithelia of the skin.

A Tyrosine-based Motif Localizes a Drosophila Vesicular Transporter to Synaptic Vesicles in Vivo

Vesicular neurotransmitter transporters must localize to synaptic vesicles (SVs) to allow regulated neurotransmitter release at the synapse. However, the signals required to localize vesicular proteins to SVs in vivo remain unclear. To address this question we have tested the effects of mutating proposed trafficking domains in Drosophila orthologs of the vesicular monoamine and glutamate transporters, DVMAT-A and DVGLUT. We show that a tyrosine-based motif (YXXY) is important both for DVMAT-A internalization from the cell surface in vitro, and localization to SVs in vivo. In contrast, DVGLUT deletion mutants that lack a putative C-terminal trafficking domain show more modest defects in both internalization in vitro and trafficking to SVs in vivo. Our data show for the first time that mutation of a specific trafficking motif can disrupt localization to SVs in vivo and suggest possible differences in the sorting of VMATs versus VGLUTs to SVs at the synapse.

Methane Diffusion Flame Dynamics at Elevated Pressures

The chamber pressure and fuel flow rate effects on the flickering behavior of methane-air diffusion flames was studied over the pressure range of 1 to 10 bar. Photomultipliers and high-speed imaging techniques have been used to study the frequency and magnitude of the flame oscillation and the change in global flame shape. The instability behavior of the flame was observed to be sensitive to both the fuel flow rate and pressure. Particularly, it has been observed that the flame responds to the change of pressure more when the pressure is relatively low. High-speed imaging has shown that the periodical break-up of the methane flame at higher flow rates is almost symmetric. However, the methane flames at lower flow rates oscillate in a more waving manner due to the alternating lateral nature of the outer vortices. The average flame luminosity was observed to increase with pressure up to 6 bar and then starts to decrease with the further increase of pressure. The flame oscillation magnitude (L f ) and oscillation wavelength (λ) were obtained from the high-speed imaging database. It has been observed that the trends of these parameters correlate well with the standard deviation (σ) of mean pixel intensity (MPI), measured from the flame high-speed images. The increase in fuel flow rate was observed to increase the magnitude of oscillation. The dominant flickering frequency of a methane diffusion flame varies with the chamber pressure as a function of P n (f = 15.7P 0.17).

Aquaporin 9 expression in the developing rat epididymis is modulated by steroid hormones

Fluid and solute transport across the epithelium of the male excurrent duct is important for sperm maturation and storage. Aquaporin 9 (AQP9), which allows permeation of water and neutral solutes, is abundant throughout the male reproductive tract, where it is expressed at the apical membrane of rat epididymal principal cells as early as at 1 week of age. We evaluated the effect of neonatal exposure to: 1) a GNRH antagonist (GNRHa); 2) diethylstilbestrol (DES); 3) ethinyl estradiol (EE); 4) DES plus testosterone (DES+TE); and 5) the anti-androgen flutamide on AQP9 expression in the epididymis of peripubertal rats. Control groups received the vehicle alone. In 25-day-old rats, quantification of the mean pixel intensity of immunofluorescence-stained sections showed a significant decrease in AQP9 staining in the apical membrane of epididymal principal cells after treatments with GNRHa, DES, or flutamide, compared to controls. These results were confirmed by western blotting. While EE induced a marked decrease in AQP9 levels by western blotting, the decrease in AQP9-associated fluorescence was not significant compared to controls. DES+TE-treated rats showed levels of AQP9 protein similar to controls, indicating maintenance of AQP9 expression by testosterone treatment in the presence of DES. Our data show that expression of AQP9 in the developing rat epididymis is downregulated by neonatal DES, GNRHa, EE, and flutamide, and that the effects mediated by estrogens can be prevented by testosterone administration.

Remote Ischemic Preconditioning Stimulus Decreases the Expression of Kinin Receptors in Human Neutrophils

Remote ischemic preconditioning (RIPC) has been shown to reduce ischemic-reperfusion injury and is induced by brief forearm ischemia. Kinins are known to be involved in RIPC and act via the G protein coupled B1 and B2 receptors. Interaction of the kinins with their respective receptors causes receptor internalization, thereby reducing the potential for further activation. This may be critical for the protective effect of RIPC and if so, we hypothesized, would significantly decrease the expression of kinin receptors on the surface of neutrophils. The study was performed on five healthy human volunteers. The left forearm was rendered ischemic for three 5-min periods, each separated by 5 min of reperfusion. Three venous blood samples were taken from the right arm, one before and two after RIPC. Neutrophil isolation, immunofluorescence labeling, and confocal microscopy were performed. Mean pixel intensity data were generated using a fixed circular area of interest (AOI, 40×40 μm). For every image, the AOI was placed over a cell and the mean pixel intensity was recorded. The mean intensity was expressed as pixel×10(2)/μm(2) and presented as mean±SEM. Immunofluorescence at the different time points was compared by one way analysis of variance with Bonferroni's post-hoc test. A P value<0.05 was considered significant. The mean pixel intensity for kinin B1 receptors was decreased at 24 h after RIPC compared with both baseline and 15 min after RIPC (P<0.001). Similarly, the intensity for B2 receptor labeling on neutrophils was significantly decreased 24 h after RIPC compared with the baseline value (P<0.001). RIPC decreases expression of kinin receptors on circulating human neutrophils. Reduction in kinin surface receptors suggests internalization of receptors and is consistent with the concepts of kinin receptor activation and their role in RIPC.

Dendritic mRNA Targeting of Jacob and N-Methyl-d-aspartate-induced Nuclear Translocation after Calpain-mediated Proteolysis

Jacob is a recently identified plasticity-related protein that couples N-methyl-d-aspartate receptor activity to nuclear gene expression. An expression analysis by Northern blot and in situ hybridization shows that Jacob is almost exclusively present in brain, in particular in the cortex and the limbic system. Alternative splicing gives rise to multiple mRNA variants, all of which exhibit a prominent dendritic localization in the hippocampus. Functional analysis in primary hippocampal neurons revealed that a predominant cis-acting dendritic targeting element in the 3'-untranslated region of Jacob mRNAs is responsible for dendritic mRNA localization. In the mouse brain, Jacob transcripts are associated with both the fragile X mental retardation protein, a well described trans-acting factor regulating dendritic mRNA targeting and translation, and the kinesin family member 5C motor complex, which is known to mediate dendritic mRNA transport. Jacob is susceptible to rapid protein degradation in a Ca(2+)- and Calpain-dependent manner, and Calpain-mediated clipping of the myristoylated N terminus of Jacob is required for its nuclear translocation after N-methyl-d-aspartate receptor activation. Our data suggest that local synthesis in dendrites may be necessary to replenish dendritic Jacob pools after truncation of the N-terminal membrane anchor and concomitant translocation of Jacob to the nucleus.

Tissue-based Quantification of 8-Hydroxy-2′-Deoxyguanosine in Human Prostate Biopsies Using Quantitative Fluorescence Imaging Analysis

To quantify 8-hydroxy-2'-deoxyguanosine (8-OHdG) in prostate stromal and acini tissue compartments from benign and cancer-containing prostate specimens using a new quantitative fluorescence imaging analysis protocol. Prostate biopsy specimens from 20 age-matched benign (control) and cancer-containing tissue sections were used to quantify 8-OHdG. 8-OHdG was quantified within individual acini nuclei and the surrounding stroma nuclei. Paraffin sections were treated with RNAse and protease to expose the nuclear chromatin, reacted with anti-8-OHdG mouse monoclonal antibody bound to saturation and detected with secondary goat anti-mouse IgG labeled with Alex Fluor 488, and quantified with a calibrated quantitative fluorescence imaging analysis system. The results were analyzed using a paired Student's t test. 8-OHdG was successfully quantified within individual cellular compartments without the need for laser tissue dissection, using the mean pixel intensity of fluorescent-labeled 8-OHdG. Matched-pair analysis of the global expression of 8-OHdG, as well as the acini and stroma individually, revealed no difference between the cancerous and control prostatic tissue. All patients with prostate cancer and those with benign findings had significantly greater 8-OHdG within the acini compared with the surrounding stoma (P < .05). A protocol to quantify 8-OHdG in paraffin-embedded human prostatic tissue was successfully developed. 8-OHdG was not significantly elevated in the acini or stroma of cancer-containing prostatic tissue compared with age-matched benign prostatic tissue. Although 8-OHdG was significantly elevated in the acini nuclei compared with the surrounding stroma nuclei in both cancer-containing and benign prostatic tissue, it, by itself, was not a strong biomarker for prostate cancer risk assessment.

Relation of mean pixel intensity to concentration of sonicated albumin microspheres: Effects of ultrasound system settings

Myocardial contrast echocardiography (MCE) is a recently developed technique to assess myocardial perfusion. Previous studies have shown that MCE frequently underestimates coronary reserve as compared with other methods. Previous reports have suggested that some of the limitations of MCE are due to the nonlinear processing algorithms of the ultrasound systems. Therefore we designed an in vitro model to study the effects of various processing algorithms and levels of acoustic power (AP) on the relation between concentration of echocontrast and mean pixel intensities. A beaker containing a commercially produced, diluted solution of sonicated albumin microspheres was imaged with a commercial Hewlett Packard ultrasound system, and mean pixel intensities were determined with an off-line computer system. The solution was imaged at a wide range of APs (40-10 dB) and time gain compensation (40-60 dB). Concentration versus intensity curves were generated using all possible combinations of compression and processing algorithms available on the ultrasound system used. Contrast effect diminished rapidly when exposed to high AP. Lower powers had less effect on contrast intensity duration, with no effect seen below 20 dB. Changes in time gain compensation did not affect contrast intensities. Regardless of the processing algorithm examined, the relation between concentration of echocontrast and mean pixel intensities was near linear in the first two to three concentrations; thereafter, the curves flattened during increasing concentrations of contrast. At higher concentrations, acoustic shadowing produced a decrease in pixel intensities.(ABSTRACT TRUNCATED AT 250 WORDS)

Relationships of changes in ultrasonographic image attributes to ovulatory and steroidogenic capacity of large antral follicles in sheep

Ovarian steroidogenesis and antral follicular development in ewes, following the treatment with medroxyprogesterone acetate (MAP) and equine chorionic gonadotrophin (eCG), are affected by the reproductive season. The objective of this study was to compare the ultrasonographic attributes of large antral follicles between cyclic (December) and seasonally anovular (June–July) ewes, after a 12-day treatment with MAP-soaked intravaginal sponges, with or without the administration of 500 IU of eCG at sponge removal, and to determine whether there is a correlation between the ultrasonographic attributes of the follicular wall and serum concentrations of oestradiol. Digital images of ovulatory follicles from cyclic ewes and eCG-treated anoestrous ewes ( n = 34 follicles), and of anovulatory follicles attaining ≥5 mm in control anoestrous ewes ( n = 8 follicles), were analysed using the spot and line techniques designed to determine the echotextural characteristics of the follicular antrum (central and peripheral), follicular wall and perifollicular ovarian stroma. The mean diameter of ovulatory follicles was greater ( P < 0.001) in cyclic than anoestrous ewes, with or without the eCG treatment. The mean pixel heterogeneity (SD of numerical pixel values) of the follicular antrum ( P < 0.05), as well as mean pixel intensity and heterogeneity of the peripheral antrum, follicular wall proper and perifollicular ovarian stroma ( P < 0.05), were consistently greater in anoestrous than cyclic ewes at the time of sponge removal and 24 h after the treatment with MAP sponges or MAP/eCG. Mean oestradiol concentrations were greater ( P < 0.05) in cyclic compared to anoestrous ewes in both MAP- and MAP/eCG-treated animals, from 1 to 2 days after sponge withdrawal. There was a moderate negative correlation ( r 2 = 0.12, P < 0.05; Pearson's Product Moment and r 2 = 0.23, P < 0.05; ANCOVA) between mean pixel heterogeneity (standard deviation of mean pixel values) of the follicular wall proper (all follicles ≥5 mm in diameter) and serum concentrations of oestradiol after sponge withdrawal. Our results indicate that large antral follicles from cyclic and seasonally anovular ewes exhibit distinctive ultrasonographic characteristics. The differences in follicular echotexture appear to be related mainly to seasonal variations in ovarian follicular morphology and oestradiol production.