Methods in quantitative image analysis

Techniques of digital image analysis for histological quantification of melanin

Morphometric analysis of tissue melanin may quantitatively contribute to research on pigmentation disorders. The authors present three methods for image analysis, which allow for identification of melanin-equivalent pixels in the epidermis using Fontana-Masson stain and, therefore, for the calculation of its percentage in the different epidermal layers. Moreover, they discuss the main elements related to the analysis and the need for rigorous standardization of the process.

Polyploidy and chromatin remodeling in hepatocytes from insulin-dependent diabetic and normoglycemic aged mice

Changes in polyploidization, chromatin supraorganization, and chromatin accessibility were investigated in hepatocytes collected from adult, nonobese diabetic (NOD) mice with increasing hyperglycemia and compared with adult normoglycemic controls and 56-week-old normoglycemic BALB/c mice. Our goal was to determine the changes in ploidy degrees and chromatin characteristics in mouse hepatocytes that are associated with insulin-dependent diabetes and to detect similarities in these aspects with those verified with aging, with greater accuracy than previous studies. Image analysis of Feulgen-stained nuclei revealed changes in ploidy degrees and chromatin supraorganization. Chromatin accessibility was assessed with micrococcal nuclease (MNase) digestion. Increased polyploidy was associated with increasing levels of glycemia, and this trend toward polyploidy was found even under normoglycemic conditions in NOD mice. Although high degrees of ploidy were also detected in aged BALB/c mice, the magnitude of polyploidy was not the same magnitude as that in the diabetic mice. While there was increased homogeneity of chromatin packaging with increasing polyploidy under conditions of severe hyperglycemia (and even under conditions of normoglycemia) in NOD mice, an inverse relationship was observed in aged BALB/c mice. Chromatin accessibility to MNase increased under severe hyperglycemia and advanced age, but it was much higher in the diabetic mice. In conclusion, although similarities in polyploidy were observed between the hepatocytes from increasingly hyperglycemic adult mice and those from normoglycemic aged mice, the relationship between chromatin remodeling and increases in ploidy degrees was not the same between the hepatocytes of these two groups. These findings demonstrate that strict similarities between diabetes and aging are not always true at the cellular level. This discordance is likely due to differences in the metabolic state of mouse hepatocytes during aging and diabetic conditions consequent to specificities in their gene regulatory programs.

Microglial activation in the injured and healthy brain: what are we really talking about? Practical and theoretical issues associated with the measurement of changes in microglial morphology

Recently it has become apparent that microglia play a role not only in responding to insults within the central nervous system but also in responding to changes in synaptic activity and potentially modulating synaptic function. This has led to an enormous expansion of interest in how microglia respond to both pathological and nonpathological challenges, with activities that are associated with unique morphological transformations. Examining changes in microglial morphology can provide direct insight into the cells' functional activities, as morphological status is recognized to be tightly coupled with function. Despite these advances in knowledge, many of the image-based morphometric procedures used to investigate changes in microglial morphology have not kept pace. This has created a situation in which morphometric approaches that have been extensively employed in the past can no longer provide accurate information on the complex transformations that microglia can undergo, particularly under non-pathological conditions. This review critically examines the strengths and weaknesses of existing morphometric analysis procedures. This review further examines efforts to improve the utility of existing approaches and discusses new developments, such as digital reconstruction, that yield more accurate and specific information on how microglia remodel themselves. Ultimately, an improved understanding of the strengths and limitations of existing, and emerging, morphometric approaches will greatly facilitate efforts to understand how microglia remodel themselves in response to the full spectrum of challenges that they are known to encounter.

Semi-automatic counting of connexin 32s immunolocalized in cultured fetal rat hepatocytes using image processing

Connexin 32s (Cx32s) were immunolocalized in fetal rat hepatocytes and their distribution was determined qualitatively. We used image analysis using a quantitative index (QI) of Cx32 (QI Cx32) defined as the area of Cx32s/number of cells in cultured fetal rat hepatocytes. Hepatocytes from livers of fetal rats were separated by collagenase digestion and low centrifugation on gestational day 17. Cells were cultured for 3 days in dexamethasone (DEX)-supplemented medium (Dex0). The medium was replaced with fresh medium and cells were continuously cultured for 3 days with DEX or epidermal growth factor supplemented medium (Dex3 or EGF3). After culture termination, cells were fixed and stained using the fluorescein-labeled antibody method for Cx32s and diaminophenylindole staining for nuclei. Thirty pairs of histological images for Cx32s and nuclei, 180 images in total, were obtained from each condition. The QI Cx32 significantly increased from 284.1 ± 102.0 (mean and SD, n=26) of Dex0 to 428.9 ± 101.0 of Dex3 (n=28) (P<0.05, Kruskal-Wallis test, then Steel-Dwass test). The increase of QI Cx32 was compatible with the morphological observations. The image analysis processing time after preparation for 180 images was reduced from 8h needed for manual operations to 1 min using ImageJ software with our macro routine.

You Gui Wan can reverse atrophic effect of ovariectomy on rat vaginal fold and blood vessels in the lamina propria

The aim of this study is to investigate whether or not You Gui Wan (YGW), a classical herbal formula in Traditional Chinese Medicine (TCM), has an impact on rat uterine and vaginal atrophic processes induced by ovariectomy (OVX). Thirty-four OVX Sprague-Dawley (SD) rats were randomly divided into three sets, and orally administrated with YGW decoction, saline or estrogen for 11 weeks, respectively. Histomorphological changes of the uterus and vagina, and serum estradiol levels were then compared. Results showed that OVX caused a dramatic atrophy of the uterus and vagina in the rats. Estrogen replacement reversed the effect of OVX, but with a side effect of endometrial hyperplasia. YGW had no significant effect on blood estradiol concentration or uterine histology, but it significantly overturned the atrophic processes of the vaginal fold and blood vessels in the lamina propria. In order to initially explore the mechanisms underlying these effects, immunostaining of estrogen receptor (ER)-α and -β in the vagina was performed. It was shown that OVX reduced expressions of ER while YGW and estrogen replacement reversed this reduction. Our findings suggest that YGW can reverse the atrophic effect of OVX on rat vaginal plica and blood vessels in the lamina propria with little adverse effect on endometrial hyperplasia. This indicates the herbal formula as an alternative to hormone replacement therapy in the management of menopausal vaginal atrophy. Recovery of ER expressions in the vagina might be one of mechanisms underlying the effects of YGW.

Histomorphometry of the ligaments using a generic-purpose image processing software, a new strategy for semi-automatized measurements

Gold chloride technique can be combined with Adobe Photoshop® software to yield a quantitative assessment of the different areas in heterogeneous structures as are ligament. A semi-automatized method based on the sum of two- and three-dimensional morphological criteria upon colorimetric criteria allows the identification and measurement of the area occupied by a structure of interest. It also allows the quantification of color intensity to differentiate structures with similar staining avidity, like vessels and nerves. This computer-assisted, semiquantitative procedure for computerized morphometry is relatively simple to perform. The accuracy, efficiency, and reproducibility of this method based on a commercially available imaging program were considered adequate when tested on the anterior cruciate ligament of the cat. Image normalization by trained observers using a commercially available software package designed for photography, applied to a sample randomly chosen, has provided the means of making reproducible measurements of heterogeneous structures.

Mitochondrial Ca(2+) uptake is essential for synaptic plasticity in pain

The increase of cytosolic free Ca(2+) ([Ca(2+)](c)) due to NMDA receptor activation is a key step for spinal cord synaptic plasticity by altering cellular signal transduction pathways. We focus on this plasticity as a cause of persistent pain. To provide a mechanism for these classic findings, we report that [Ca(2+)](c) does not trigger synaptic plasticity directly but must first enter into mitochondria. Interfering with mitochondrial Ca(2+) uptake during a [Ca(2+)](c) increase blocks induction of behavioral hyperalgesia and accompanying downstream cell signaling, with reduction of spinal long-term potentiation (LTP). Furthermore, reducing the accompanying mitochondrial superoxide levels lessens hyperalgesia and LTP induction. These results indicate that [Ca(2+)](c) requires downstream mitochondrial Ca(2+) uptake with consequent production of reactive oxygen species (ROS) for synaptic plasticity underlying chronic pain. These results suggest modifying mitochondrial Ca(2+) uptake and thus ROS as a type of chronic pain therapy that should also have broader biologic significance.

Computer-aided detection scheme for sentinel lymph nodes in lymphoscintigrams using symmetrical property around mapped injection point

It is difficult to detect sentinel lymph nodes (SLNs) around an injection point of radiopharmaceuticals mapped in lymphoscintigrams. The purpose of this study was to develop a computer-aided detection (CAD) scheme for SLNs by a subtraction technique using the symmetrical property in the mapped injection point. Our database consisted of 78 lymphoscintigrams with 86 SLNs. In our CAD scheme, the mapped injection point of radiopharmaceuticals was first segmented from the lymphoscintigram using a gray-level thresholding technique. Lymphoscintigram was then divided into four regions by vertical and horizontal straight lines through the center of the segmented injection point. One of the four divided regions was defined as the target region. The correlation coefficients based on pixel values were calculated between the target region and each of the other three regions. The region with the highest correlation coefficient among three regions was selected as the similar region to the target region. The values of pixels on the target region were subtracted by the values of the corresponding pixels on the similar region. This procedure was repeated until every divided region had been used as target region. SLNs were segmented by applying a gray-level thresholding technique to the subtracted image. With our CAD scheme, sensitivity and the number of false positives were 95.3% (82/86) and 2.51 per image, respectively. Our CAD scheme achieved a high level of detection accuracy, and would have a great potential in assisting physicians to detect SLNs in lymphoscintigrams.

Transfection of truncated bone morphogenetic protein receptor-II into oral squamous cell carcinoma cell line Tca8113 and inhibitory effect on proliferation and inductive effect on apoptosis

Bone morphogenetic proteins (BMPs), one of the crucial regulators in embryonic development and bone formation, have been implicated in epithelium-derived tumors. Previous results showed the involvement of overexpression of BMP 2, 4, 5 in the carcinogenesis of oral epithelia. The ability of BMP receptor-II mutant to modify the malignant phenotype of oral squamous cell carcinoma cell line Tca8113 by blocking the BMP signal transduction pathway has been proposed. In this study, a negative truncated mutant of the BMP receptor-II (tBMPR-II) was transfected into Tca8113 cells. The effects were evaluated though RT-PCR, 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay, BrdU staining, cell cyclin assay, TdT-mediated dUTP nick end labeling (TUNEL) staining, and cell cycle protein detection. Overexpression of tBMPR-II gene transfection truncates the expression of BMPR-II mRNA expression, but not BMP 2, 4, 5. tBMPR-II resulted in a remarkable inhibition of cell proliferation and viability compared with control Tca8113. The inhibitory effects were partly attributed to the induction of apoptosis and cell cycle arrest in G(0) /G(1) accompanied by downregulation of the intracellular cell cycle proteins of cyclin D1 and cyclin-dependent kinases 4, as well as the upregulation of p27 and p57. Loss of BMP signals correlates tightly with suppression of cell proliferation, induction of apoptosis, and benign transformation of Tca8113 cells phenotype.

Quantification of sudomotor innervation: a comparison of three methods

Peripheral sudomotor dysfunction is present in many peripheral neuropathies, but structural assessments of sudomotor fibers rarely occur. We evaluated 36 diabetic and 72 healthy control subjects who underwent detailed neurologic examinations and punch skin biopsies. Physical exam findings were quantified by neuropathy impairment score in the lower limb. Skin biopsies quantified intraepidermal nerve fiber density (IENFD) and sweat gland nerve fiber density (SGNFD) by a manual, automated, and semiquantitative method. The automated and manual SGNFD correlated with the IENFD at the same site (r = 0.62, P < 0.05 automated method, r = 0.67, P < 0.05 manual method). As neuropathy worsened, the SGNFD at the distal leg declined (automated counting r = -0.81, P < 0.001; manual counting r = -0.88, P < 0.001). The semiquantitative method displayed poor inter- and intrareviewer reliability and correlated poorly with standard neuropathy evaluation scores. Our results suggest that sudomotor fibers can be rapidly and reproducibly quantified, and results correlate well with physical exam findings.

Robust texture features for response monitoring of glioblastoma multiforme on T1-weighted and T2-FLAIR MR images: a preliminary investigation in terms of identification and segmentation

PURPOSE

Image texture has recently attracted much attention in providing quantitative features that are unique to various different tissue types, in particular, in MR images of the brain. Such image features may be useful for tumor response quantification. As a first step, one needs to establish if these features are sensitive to different tissues of clinical relevance. Here, a novel method of texture analysis based on the Hartley transform has been investigated and applied to MR images of glioblastoma multiforme (GBM).

METHODS

Contrast-enhanced T1-weighted gradient-echo and T2-FLAIR spin-echo MR images of 27 GBM patients acquired prior to radiation therapy were available for analysis. Before computing texture features on these images, a novel image transformation was employed in the form of a power map computed from the localized Hartley transform of the image. Haralick statistical texture features were then computed based on the power map. This method was compared to the standard approach of obtaining texture features directly from the image. Twelve different features were computed on different resolution levels. On a regional resolution level, image texture features were identified that are able to correctly classify entire regions within T1-weighted and T2-FLAIR brain MR images of GBM patients into abnormal (containing contrast-enhancing GBM tumor) and brain tissue. Various metrics [area under the ROC curve (AUC), maximum accuracy, and Canberra distance] have been computed to quantify the usefulness of these features. On a local resolution level, it was investigated which of these features are able to provide a voxel-by-voxel enhancement that could be used for assisting the segmentation of the gross tumor volume on T1 images. The "gold standard" for this analysis was a gross tumor volume corresponding to the contrast-enhancing lesion visualized on T1-weighted images as segmented by a radiation oncologist.

RESULTS

The Sum-mean and Variance features demonstrated the best performance overall. For the T1-weighted images, the identification performance of Sum-mean and Variance features computed from the power map was higher (AUC = 0.9959 and AUC = 0.9918, respectively) and with higher Canberra distances as compared to features computed directly from the images (AUC = 0.8930 and AUC = 0.9163, respectively). These results in T2-FLAIR images were even superior. The features computed from the power map showed an unequivocal identification (AUC = 1) with higher Canberra distances, whereas the performance of the features from the original images was slightly lower (AUC = 0.9739 and AUC = 0.9904, respectively). The same features computed on the power map of the T1-weighted images also provided superior enhancement in individual tumor voxels as compared to the features computed on the original images.

CONCLUSIONS

The Sum-mean and Variance features are both useful for identifying and segmenting GBM tumors on localized Hartley transformed MR images.

A red line not to cross: evaluating the limitation and properness of gel image tuning procedures

Currently, results of gel electrophoresis are commonly documented in digital formats by image acquisition instruments. In this study, gel images tuned by a common image processing software package, Photoshop, were assessed to understand the transforming algorithms and their impacts on quantitative analysis. TotalLab 100, an electrophoresis gel image analysis software package, was applied for image quantitation and evaluation. The three most frequently used image tuning functions-adjustments of the brightness, contrast, and grayscale span (level) of images-were investigated using both data generated from a standard grayscale tablet and an actual electrophoresis gel image. The influences of these procedures were analyzed for the grayscale transformation between the input and output images. Although all three procedures differentially improved the visualization of the input image, adjusting the contrast of images disrupted the quantitative information because of its nonlinear transforming algorithm. Under certain conditions, adjusting the brightness or the level of images could preserve the quantitative information because of the linear transforming algorithms. It was found that when the minimum and maximum grayscales of a gel image were recognized, using a commercial software package to maximally stretch the level may significantly improve the quality of a gel image without jeopardizing quantitative analysis.

Effects of oral contraceptives or a gonadotropin-releasing hormone agonist on ovarian carcinogenesis in genetically engineered mice

Although epidemiologic evidence for the ability of combined oral contraception (OC) to reduce the risk of ovarian cancer (OvCa) is convincing, the biological mechanisms underlying this effect are largely unknown. We conducted the present study to determine if OC also influences ovarian carcinogenesis in a genetic mouse model and, if so, to investigate the mechanism underlying the protective effect. LSL-K-ras(G12D/+)Pten(loxP/loxP) mice were treated with ethinyl estradiol plus norethindrone, contraceptive hormones commonly used in combined OC, or norethindrone alone, or a gonadotropin-releasing hormone agonist. The combined OC had a 29% reduction in mean total tumor weight compared with placebo (epithelial tumor weight, -80%). Norethindrone alone reduced mean total tumor weight by 42% (epithelial tumor weight, -46%), and the gonadotropin-releasing hormone agonist increased mean total tumor weight by 71% (epithelial tumor weight, +150%). Large variations in tumor size affected the P values for these changes, which were not statistically significant. Nonetheless, the OC reductions are consistent with the epidemiologic data indicating a protective effect of OC. Matrix metalloproteinase-2 activity was decreased in association with OC, indicating that OC may affect ovarian carcinogenesis by decreasing proteolytic activity, an important early event in the pathogenesis of OvCa. In contrast, OC increased invasion in a K-ras/Pten OvCa cell line established from the mouse tumors, suggesting that OC hormones, particularly estrogen, may have a detrimental effect after the disease process is under way. Our study results support further investigation of OC effects and mechanisms for OvCa prevention.

Quantification of sweat gland innervation: a clinical-pathologic correlation

OBJECTIVE

To evaluate a novel method to quantify the density of nerve fibers innervating sweat glands in healthy control and diabetic subjects, to compare the results to an unbiased stereologic technique, and to identify the relationship to standardized physical examination and patient-reported symptom scores.

METHODS

Thirty diabetic and 64 healthy subjects had skin biopsies performed at the distal leg and distal and proximal thigh. Nerve fibers innervating sweat glands, stained with PGP 9.5, were imaged by light microscopy. Sweat gland nerve fiber density (SGNFD) was quantified by manual morphometry. As a gold standard, three additional subjects had biopsies analyzed by confocal microscopy using unbiased stereologic quantification. Severity of neuropathy was measured by standardized instruments including the Neuropathy Impairment Score in the Lower Limb (NIS-LL) while symptoms were measured by the Michigan Neuropathy Screening Instrument.

RESULTS

Manual morphometry increased with unbiased stereology (r = 0.93, p < 0.01). Diabetic subjects had reduced SGNFD compared to controls at the distal leg (p < 0.001), distal thigh (p < 0.01), and proximal thigh (p < 0.05). The SGNFD at the distal leg of diabetic subjects decreased as the NIS-LL worsened (r = -0.89, p < 0.001) and was concordant with symptoms of reduced sweat production (p < 0.01).

CONCLUSIONS

We describe a novel method to quantify the density of nerve fibers innervating sweat glands. The technique differentiates groups of patients with mild diabetic neuropathy from healthy control subjects and correlates with both physical examination scores and symptoms relevant to sudomotor dysfunction. This method provides a reliable structural measure of sweat gland innervation that complements the investigation of small fiber neuropathies.

In vitro comparative study of vibro-acoustography versus pulse-echo ultrasound in imaging permanent prostate brachytherapy seeds

BACKGROUND

Permanent prostate brachytherapy (PPB) is a common treatment for early stage prostate cancer. While the modern approach using trans-rectal ultrasound guidance has demonstrated excellent outcome, the efficacy of PPB depends on achieving complete radiation dose coverage of the prostate by obtaining a proper radiation source (seed) distribution. Currently, brachytherapy seed placement is guided by trans-rectal ultrasound imaging and fluoroscopy. A significant percentage of seeds are not detected by trans-rectal ultrasound because certain seed orientations are invisible making accurate intra-operative feedback of radiation dosimetry very difficult, if not impossible. Therefore, intra-operative correction of suboptimal seed distributions cannot easily be done with current methods. Vibro-acoustography (VA) is an imaging modality that is capable of imaging solids at any orientation, and the resulting images are speckle free.

OBJECTIVE AND METHODS

The purpose of this study is to compare the capabilities of VA and pulse-echo ultrasound in imaging PPB seeds at various angles and show the sensitivity of detection to seed orientation. In the VA experiment, two intersecting ultrasound beams driven at f(1)=3.00 MHz and f(2)=3.020 MHz respectively were focused on the seeds attached to a latex membrane while the amplitude of the acoustic emission produced at the difference frequency 20 kHz was detected by a low frequency hydrophone.

RESULTS

Finite element simulations and results of experiments conducted under well-controlled conditions in a water tank on a series of seeds indicate that the seeds can be detected at any orientation with VA, whereas pulse-echo ultrasound is very sensitive to the seed orientation.

CONCLUSION

It is concluded that vibro-acoustography is superior to pulse-echo ultrasound for detection of PPB seeds.

Protein kinase C beta in malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is a disease with few therapeutic options. Protein kinase C beta (PKCbeta) is involved in important cellular functions. Enzastaurin (LY317615.HCl) is a novel inhibitor of PKC in clinical development. MPM cell lines (7) and patient tumor tissues (24) were evaluated for expression of PKCbeta by immunoblotting and immunohistochemistry, respectively. In-vitro cell growth assays were performed with enzastaurin with or without cisplatin. Cell migration was evaluated with the wound healing assay. Downstream signaling (survival and focal adhesion pathways) was studied by immunoblotting for related molecules in the presence of phorbol ester with or without enzastaurin. Expression for PKCbeta1 was seen in all cases, with a mean integrated optical density of 152.5 (standard deviation=95.47, n=24), whereas PKCbeta2 expression was less intense, with a mean integrated optical density of 11.45 (standard deviation=16.27, n=21). There was a trend toward lower overall survival among patients expressing above-median PKCbeta1 (P=0.064), but not PKCbeta2. Robust expression of PKCbeta1 and low expression of PKCbeta2 were observed in MPM cell lines. Treatment of MPM cell lines with enzastaurin revealed an IC50 of 5 micromol/l, and strong synergism was observed when combined with cisplatin. Wound healing assay revealed that treatment of H2461 cells with enzastaurin reduced migration by 59.2%. Enzastaurin treatment led to disruption of F-actin architecture. Downstream signaling showed reduced phosphorylation of AKT, FAK (focal adhesion kinase), p130Cas, S6 ribosomal protein, and paxillin. PKCbeta1 was expressed in the majority of MPM samples. Enzastaurin has preclinical activity against MPM, and exhibited synergism with cisplatin. PKCbeta inhibition in MPM might be able to reduce the invasiveness of MPM by affecting cytoskeletal function.

Increased production of mitochondrial superoxide in the spinal cord induces pain behaviors in mice: the effect of mitochondrial electron transport complex inhibitors

Scavengers of reactive oxygen species (ROS) have been shown to produce a strong antinociceptive effect on persistent pain, and mitochondria are suggested to be the main source of ROS in the spinal dorsal horn. To explore whether excessive generation of mitochondrial superoxide alone can induce pain, the effect of mitochondrial electron transport complex inhibitors on the development of mechanical hyperalgesia was examined in mice. Intrathecal injection of an electron transport complex inhibitor, antimycin A or rotenone, in normal mice resulted in a slowly developing but long-lasting and dose-dependent mechanical hyperalgesia. The levels of mechanical hyperalgesia after antimycin A, a complex III inhibitor, were higher than that with rotenone, a complex I inhibitor. A large increase of mitochondrial superoxide in the spinal dorsal horn and a strong antinociceptive effect of ROS scavengers, phenyl-N-tert-butylnitrone (PBN) and 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPOL) were observed in antimycin A-treated mice. The study indicates that the enhanced production of spinal mitochondrial superoxide alone without nerve injury can produce mechanical hyperalgesia.

Transplantation of immortalized mesencephalic progenitors (CSM14.1 cells) into the neonatal parkinsonian rat caudate putamen

The present study analyzed whether grafts of the mesencephalic progenitor cell line CSM14.1 into the neonatal rat caudate putamen (CPu) differentiate into neurons and whether this is accompanied by a functional improvement in 6-hydroxydopamine (6-OHDA)-lesioned animals. As in previous studies, a neuronal differentiation of CSM14.1 cells transplanted into the CPu of adult animals could not be observed, so we here used neonatal rats, because graft location and host age seemingly are crucial parameters for neural transplant differentiation and integration. Rats bilaterally lesioned at postnatal day 1 by intraventricular 6-OHDA-injections 2 days later received 100,000 CSM14.1 cells prelabelled with the fluorescent dye PKH26 into the right CPu. Five weeks after grafting, the cylinder test was performed, and the data compared with data from age-matched intact controls and bilaterally lesioned-only animals. Brain slices immunostained for tyrosine hydroxylase (TH) were quantified by optical densitometry. We observed a significant preference of left forelimb use exclusively in transplanted animals. In these rats, TH-containing perikarya were found in the grafted CPu, presumedly leading to the significant increase of TH-immunoreactive fibers in this region. Moreover, confocal laser microscopy revealed a differentiation of transplanted PKH26-labelled CSM14.1 cells into neuronal nuclei antigen or TH-immunoreactive cells. Thus, CSM14.1 cells differentiate into TH-containing neurons, which most probably contribute to the preferred forelimb use, indicating a functional integration of CSM14.1 cells into the host basal ganglia loops during early postnatal development. These findings that are in contrast to observations in adult rats suggest instructive cues for neuronal differentiation and integration given by the neonatal microenvironment.

DNA content and chromatin texture of human breast epithelial cells transformed with 17-beta-estradiol and the estrogen antagonist ICI 182,780 as assessed by image analysis

The immortalized human breast epithelial MCF-10F cell line, although estrogen receptor alpha negative, develops cell proliferating activities and invasiveness indicative of neoplastic transformation, after treatment with 17-beta-estradiol (E-2). These effects are similar to those produced by benzo[a]pyrene (BP). Since we have previously reported changes in the nuclear parameters accompanying BP-induced tumorigenesis in MCF-10F cells, we have examined whether similar alterations occur in E-2-treated cells. We therefore studied DNA amounts and other nuclear parameters in Feulgen-stained MCF-10F cells after treatment with various concentrations of E-2, BP, the estrogen antagonist ICI 182,780, and E-2 in the presence of ICI 182,780. E-2 caused a certain loss of DNA and changes in the nuclear size and chromatin supraorganization of MCF-10F cells. Many of these changes were similar to those produced by BP and were indicative of neoplastic transformation. More intense chromatin remodelling was seen with 70 nM E-2. Since these changes were not abrogated totally or partially by ICI 182,780, the neoplastic transformation of MCF-10F cells stimulated by E-2 involved a process that was independent of estrogen alpha-receptors. The changes produced by ICI 182,780 alone were attributed to effects other than its well-known anti-estrogenic activity.

Nucleus image properties assessed by video image analysis in mouse hepatocytes under a short lysis for extended chromatin fiber formation

BACKGROUND

How much DNA remains in mouse hepatocyte nuclei after extended chromatin fiber (ECF) formation or whether this content varies within the nuclear population is not known. This information could be relevant to understanding chromatin extensibility as related to chromatin organization, possibly associated with variable nuclear activities in hepatocytes.

METHODS

A protocol for ECF formation under the gravity action, image analysis of Feulgen-stained unfixed mouse hepatocyte remnants, and DAPI fluorescence were used.

RESULTS

Areas, shape, Feulgen-DNA amounts, and chromatin texture were affected in unfixed, lysed nuclei. The Feulgen-DNA values in nuclear remnants represented 37% of the content in fixed, nonlysed nuclei in terms of median values; the coefficient of variation of Feulgen-DNA values in the nuclear remnants was much higher than those in controls. Enhancement in DAPI fluorescence was evident in chromocenters of the fixed nuclei and in remnants and some ECF granules of the unfixed, lysed nuclei.

CONCLUSIONS

The DNA content of the nuclear remnants was much more variable than that assumed from known variability in hepatocyte ploidy degrees. The variable constraint to chromatin extrusion from hepatocyte nuclei is hypothesized to depend on variable chromatin organization with possible involvement of nuclear matrix association, transcriptional activities, and AT-rich DNA-containing heterochromatin.

Quantitative analysis of fibrosis formation on the microcapsule surface with the use of picro-sirius red staining, polarized light microscopy, and digital image analysis

Transplantation of microencapsulated cells shows potential to treat a variety of diseases. To improve the quality of microcapsules, efficient methods need to be established and standardized for the evaluation of biocompatibility of microcapsules. To this end, a microscopical method was developed to analyze quantitatively the degree of fibrotic overgrowth (FO), which serves as the index of biocompatibility. In this method, sections were stained with picro-sirius red and illuminated with a polarized light microscope. The images were digitized with the use of a computer-video system in which collagenous content was depicted by gray levels 1 to 255. Both the area of collagen and the thickness of FO were examined. The ratio of Type I/Type III collagen and the thickness were used as indexes of the degree of FO. The data showed that the ratio of Type I/Type III collagen and the thickness increased with time, and FO was not significant 4 weeks after transplantation. In comparison, this new method is more efficient to evaluate FO.

Texture analysis of speckle in optical coherence tomography images of tissue phantoms

Optical coherence tomography (OCT) is an imaging modality capable of acquiring cross-sectional images of tissue using back-reflected light. Conventional OCT images have a resolution of 10-15 microm, and are thus best suited for visualizing tissue layers and structures. OCT images of collagen (with and without endothelial cells) have no resolvable features and may appear to simply show an exponential decrease in intensity with depth. However, examination of these images reveals that they display a characteristic repetitive structure due to speckle. The purpose of this study is to evaluate the application of statistical and spectral texture analysis techniques for differentiating living and non-living tissue phantoms containing various sizes and distributions of scatterers based on speckle content in OCT images. Statistically significant differences between texture parameters and excellent classification rates were obtained when comparing various endothelial cell concentrations ranging from 0 cells/ml to 25 million cells/ml. Statistically significant results and excellent classification rates were also obtained using various sizes of microspheres with concentrations ranging from 0 microspheres/ml to 500 million microspheres/ml. This study has shown that texture analysis of OCT images may be capable of differentiating tissue phantoms containing various sizes and distributions of scatterers.

The xenoestrogen bisphenol A in the Hershberger assay: androgen receptor regulation and morphometrical reactions indicate no major effects

We evaluated androgen-like effects of bisphenol A (BPA) using orchiectomized Wistar rats. Animals were treated p.o. either with vehicle or with 3, 50, 200, 500 mg/kgbw/day BPA (n=13) for 7 days. One group was treated s.c. with 1mg/kgbw/day testosterone propionate (TP). Flutamide (FL) (3mg/kgbw/day, p.o.) was used to antagonize androgen effects of the suprapharmacological dose (500 mg/kgbw/day) of BPA. Androgen-like effects of BPA on prostates and seminal vesicles were assessed by the Hershberger assay, densitometric analysis of androgen receptor (AR) immunoreactivity, cell proliferation-index and a morphometric analysis. Absolute weights of prostates and seminal vesicles were not increased by BPA, whereas the relative weights were increased at higher doses of BPA, most likely due to a decrease in body weight. Staining intensity for AR immunoreactivity was increased at low but not at higher doses of BPA in comparison to the orchiectomized rats. BPA at all doses tested did not cause an increase of the cell proliferation-index. Epithelial height and glandular luminal area were increased by low doses of BPA, whereas higher doses caused a decrease of these parameters. The data provide evidence that BPA does not exert major androgenic effects.

Quantitative analysis of atherosclerotic lesion composition in mice

Comparative quantitation has become an increasingly desirable tool in determining compositional differences of aortic plaque lesion in transgenically altered mice. To this end, methodology has been developed to identify lipid, cellularity, collagen, and elastin components using traditional bright-field microscopy, fluorescence, and polarized light microscopy, employing both confocal and wide-field imaging systems. Subsequent imaging processing and analysis on the digitally captured images reveals differences in compositional components as influenced by diet, age and gender. This method can be expanded to employ a rich variety of histochemical and immunohistochemical staining protocols.

A quantitative determination of multi-protein interactions by the analysis of confocal images using a pixel-by-pixel assessment algorithm

MOTIVATION

Recent advances in confocal microscopy have allowed scientists to assess the expression, and to some extent, the interaction/colocalization of multiple molecules within cells and tissues. In some instances, accurately quantifying the colocalization of two or more proteins may be critical. This can require the acquisition of multiple Z plane images (Z stacks) throughout a specimen and, as such, we report here the successful development of a freeware, open-source image analysis tool, IMAJIN_COLOC, developed in PERL (v. 5.8, build 806), using the PERLMagick libraries (ImageMagick). Using a pixel-by-pixel analysis algorithm, IMAJIN_COLOC can analyze images for antigen expression (any number of colors) and can measure all possible combinations of colocalization for up to three colors by analyzing a Z stack gallery acquired for each sample. The simultaneous (i.e. in a single pass) analysis of three-color colocalization, and batch analysis capabilities are distinctive features of this program.

RESULTS

A control image, containing known individual and colocalized pixel counts, was used to validate the accuracy of IMAJIN_COLOC. As further validation, pixel counts and colocalization values from the control image were compared to those obtained with the software packaged with the Zeiss laser-scanning microscope (LSM AIM, version 3.2). The values from both programs were found to be identical. To demonstrate the applicability of this program in addressing novel biological questions, we examined the role of neurons in eliciting an immune reaction in response to viral infection. Specifically, we successfully examined expression of the chemokine RANTES in measles virus (MV) infected hippocampal neurons and quantified changes in RANTES production throughout the disease period. The resultant quantitative data were also evaluated visually, using a gif image created during the analysis.

AVAILABILITY

PERL (ActivePerl, version 5.8) is available at activestate.com; the PERLMagick libraries are available at imagemagick.org, and IMAJIN_COLOC, the source code and user documentation can be downloaded from http://www.fda.gov/cber/research/imaging/imageanalysis.htm.

Spectral characteristics of acute lymphoblastic leukemia in childhood

Although the differentiation and classification of acute leukemia are based upon cytochemical features as well as immunologic, cytogenetic, and molecular characteristics, in many cases the morphological distinction of normal lymphocytes from lymphoblasts of acute lymphoblastic leukemia (ALL) is difficult using light microscopy. In this study the distinction between normal lymphocytes and lymphoblasts of childhood ALL is proposed using their spectral characteristics. The method has been based upon the analysis and classification of optical absorption characteristics of the bone marrow cells. Spectral microscopy system is capable of capturing a great number of narrow-band images, in the wide spectral range of the optical spectrum. The analysis showed statistically significant difference (P < 0.0001) between normal lymphocytes and lymphoblasts as far as it concerns the detection, identification and mapping of their spectral absorption characteristics. Our results suggest the potential of spectral imaging as a new method for the distinction of lymphocytes from lymphoblasts in cases that with the light microscope, the morphologic differences are not visible in the bone marrow smears at diagnosis or the follow up of the children with ALL.

Quinolinic acid lesions of the caudate putamen in the rat lead to a local increase of ciliary neurotrophic factor

When applied prior to excitotoxic lesions, ciliary neurotrophic factor (CNTF) has been shown to be neuroprotective. However, data concerning the endogenous CNTF content of the intact rat striatum are rare and have not until now been available for the quinolinic acid (QA)-lesioned striatum. Therefore, we investigated the CNTF content in the QA-lesioned rat striatum for at least 1 month using immunohistochemistry and Western blot analysis. In lesioned striata a neuronal loss was observed by Nissl staining and by a reduction of NeuN-immunoreactive cells, whereas increased glial fibrillary acidic protein immunoreactivity showed a gliotic reaction. With CNTF immunohistochemistry we found that in the QA-lesioned striatum CNTF was increased over time, whereas it was not detectable in intact and sham-lesioned striata. CNTF-immunoreactive cells had the morphology of protoplasmatic astrocytes. Furthermore, quantitative Western blotting demonstrated that the content of CNTF protein from striatal lysates containing 1 mg of whole protein 1 month after QA lesioning (2.76 +/- 1.71 ng) was significantly increased (P < 0.05, U-test) compared with sham-lesioned hemispheres (0.68 +/- 0.25 ng) and intact controls (0.55 +/- 0.25 ng). We conclude that CNTF content is correlated with glial scar formation and suggest that our results may be of relevance to cell grafting strategies for the treatment of Huntington's disease.

Comparison of contrast, sensitivity and efficiency of signal amplified and nonamplified immunohistochemical reactions suitable for videomicroscopy-based quantification and neuroimaging

In recent years, many different technical modifications of immunohistochemical methods have been developed. The selection of a suitable technique for quantitative purposes such as mapping studies can be quite difficult. Various features of a certain method must be considered such as the sensitivity, costs, duration and practicability with respect to serial sectioned specimens. Background and foreground difference or contrast and the influence of artifacts are major problems of quantitative immunohistochemistry. It is not known which of the different modifications of immunohistochemical signal amplifications and non-amplifications gives optimal results in respect to image analytical-based quantification. However, for image analysis, it is important to analyze sections which offer a sufficient contrast between foreground and background. The sensitivity of a system is crucial when quantitative immunohistochemistry should be applied to scarce material with longer postmortem and storage times which occur often by processing human brains. In addition, the enzyme-substrate reactions have an obvious influence on this criterion; therefore, different substrates were also tested. The contrast may be as well effected by the quality and specificity of the primary antibody, the type of tissue and naturally by preparative (fixation, postmortem delay, storage) and individual factors (age, circadian effects, diseases, sex). Because all of these factors may yield to different results by combining them with different neuronal structures, we used three different antigen expressions for a specific analysis: fibrillary, granulary and perikaryal antigen distributions in brains from Wistar rats. Principally, the sensitivity of the modifications of immunohistochemical amplifications is revealed more strongly than without enhancement steps; however, the contrast between foreground and background structures does not necessary increase by applying a certain amplification technique. The lowest contrast (15%) was detected after applying the labelled streptavidin-biotin technique. All other methods offer comparable contrasts in between 30% and 40%. The catalyzed signal amplification reaction has been found to give optimal results (40% contrast) for image analysis. However, from the technical point of view and variability of protein expression, storage and postmortem delay, it was necessary to adapt the commercial CSA Kit from Dako (K1500). The modified technique, called C2 method, offers better results with respect to sensitivity, total costs, duration and contrast (60%) and variability of contrast.

Androgen-dependent morphology of prostates and seminal vesicles in the Hershberger Assay: Evaluation of immunohistochemical and morphometric parameters

The aim of this study was to evaluate androgen-like effects using immunohistochemical and morphometric methods. Therefore, orchiectomized Wistar rats (n > or = 13) were treated s.c. with 1 mg/kg bw/day testosterone propionate (TP) for 7 days and compared to orchiectomized rats without TP substitution (OX) and to an untreated intact control group. Sections obtained from prostates and seminal vesicles were stained with polyclonal and monoclonal antibodies against the androgen receptor (AR) and assessed densitometrically (intensity of the immunoreaction) and morphometrically (epithelial height, luminal area). TP caused an enhancement of staining intensity and an increase in organ weights, epithelial height and luminal area. The use of proliferation markers (PCNA, MIB-5) showed also a highly significant increase of immunoreactive cells in TP-substituted orchiectomized rats compared with the OX group. Based on the present data, the densitometric analysis of AR-immunoreactivity as well as the assessment of proliferation markers, epithelial height and luminal area proved to be sensitive parameters for the evaluation of androgen effects on prostates and seminal vesicles. In further studies these parameters will be used to test several industrial xenooestrogens as well as phytooestrogens on their possible androgenic capacity.

Measurement of the ultrasound backscatter signal from three seed types as a function of incidence angle: application to permanent prostate brachytherapy

PURPOSE

To measure the relative ultrasound backscatter of different seed types as a function of seed orientation and to evaluate the corresponding images of these seeds.

METHODS AND MATERIALS

Three seed types were evaluated: OncoSeed (standard), EchoSeed (corrugated), and RAPID Strand(RS). Ultrasound images for angles of incidence varying from 90 degrees (perpendicular) to 20 degrees at 5MHz and 7.5MHz were produced by raster scanning the seeds in a degassed water bath. Seed images were visually inspected and analyzed using the integrated-optical-density (IOD) method.

RESULTS

Corrugated seeds appear as contiguous objects over the range of frequencies and orientations examined, whereas standard seeds appear as contiguous objects from 90 degrees to 80 degrees only. The ranges and means of the backscattered IOD ratio of the seeds from 85 degrees to 20 degrees were: (corrugated vs. standard) 1.48 to 3.72 (2.32 +/- 0.62) for 5 MHz and 1.26 to 3.77 (2.19 +/- 0.84) for 7.5 MHz and (corrugated vs. RS) 1.21 to 9.53 (2.98 +/- 2.48) for 5 MHz and 1.008 to 10.86 (2.79 +/- 3.08) for 7.5 MHz. Backscattered signal increase ranged from 1.66 dB to 20.7 dB for the corrugated seed as compared to the other seeds.

CONCLUSIONS

Corrugated seeds produce greater backscatter signal and a more readily identifiable seed image over a large range of seed orientation as compared with standard brachytherapy seeds.

Pixel-based criteria-oriented analysis of time-lapse Ca2+-fluorescence images

Since its inception, the analysis of time-lapse video-images acquired during Ca2+ imaging experiments using fluorescence microscopy has been progressively optimized for achieving a high temporal resolution. In contrast, the spatial resolution of the acquired images is often compromised during analysis to varying degrees by the need to draw regions of interest (ROI). We developed a strategy to analyze images at the acquired spatial resolution-pixel-by-pixel, grouping all pixels based on criteria of interest (COI) in regard to their associated fluorescence values over time and visualizing the distributions of the pixel-groups detected in a pseudo-colored map. We applied this pixel-based COI-strategy to the analysis of relative intracellular free calcium levels (Ca(i)(2+)) in attached cultured embryonic hippocampal cells under baseline and experimental conditions designed to evaluate the contribution of extracellular Ca2+ (Ca(e)(2+)) to baseline Ca(i)(2+) levels. We discovered distinct groups of Ca(e)(2+)-dependent Ca(i)(2+) regulation patterns emergent during the earliest phases of hippocampal cell differentiation, which were not limited to inter-cell differences. Thus, pixel-based COI-analysis of time-lapse images can be used to disclose distinct patterns of Ca(e)(2+)-dependent Ca(i)(2+) levels and their corresponding subcellular distributions in developing hippocampal cells. Such a strategy should be useful in studying the emergence and distribution of Ca(i)(2+) signaling at subcellular levels of resolution using fluorescence microscopy.

Texture analysis of optical coherence tomography images: feasibility for tissue classification

Optical coherence tomography (OCT) acquires cross-sectional images of tissue by measuring back-reflected light. Images from in vivo OCT systems typically have a resolution of 10 to 15 mm, and are thus best suited for visualizing structures in the range of tens to hundreds of microns, such as tissue layers or glands. Many normal and abnormal tissues lack visible structures in this size range, so it may appear that OCT is unsuitable for identification of these tissues. However, examination of structure-poor OCT images reveals that they frequently display a characteristic texture that is due to speckle. We evaluated the application of statistical and spectral texture analysis techniques for differentiating tissue types based on the structural and speckle content in OCT images. Excellent correct classification rates were obtained when images had slight visual differences (mouse skin and fat, correct classification rates of 98.5 and 97.3%, respectively), and reasonable rates were obtained with nearly identical-appearing images (normal versus abnormal mouse lung, correct classification rates of 64.0 and 88.6%, respectively). This study shows that texture analysis of OCT images may be capable of differentiating tissue types without reliance on visible structures.

DNA content, chromatin texture and nuclear morphology in benzo[a]pyrene-transformed human breast epithelial cells after microcell-mediated transfer of chromosomes 11 and 17

BACKGROUND

A relation between the changes in DNA content and chromatin supra-organization and the expression of gradual steps of tumorigenesis has been assessed by image analysis in human breast epithelial cells (MCF-10F) treated with benzo[a]pyrene (BP) (cell lines BP1, BP1-E, BP1-Tras, and others).

METHODS

Because abnormal chromosomes 11 and 17 have been associated with neoplastic progression in BP-transformed MCF-10F cells, image analysis of Feulgen-stained tumorigenic BP1-E cells with the microcell-mediated chromosome transfer of normal chromosomes 11 and 17 was carried out.

RESULTS

A tendency of DNA amount distribution and nuclear size restoration to values typical of non-transformed MCF-10F cells was demonstrated, especially after the transfer of chromosome 17. No reversion in chromatin texture was found after the transfer of chromosome 11 or 17.

CONCLUSIONS

Although the presence of a normal chromosome 17 should be considered among the necessary steps for tumorigenic human breast epithelial cells to recover their normality, a more complex genome balance is required for the entire nuclear chromatin of these cells to recover its totally normal supra-organization and expression.

Quantifying cell scattering: the blob algorithm revisited

BACKGROUND

A method to objectively quantify cell scattering would permit quantitative evaluation of therapies and compounds intended to affect this physiologic process, which has relevance to normal (e.g., development) and pathologic (e.g., metastasis) events.

METHODS

A grid-based modified blob analysis was performed on a set of images of Madin-Darby Canine Kidney (MDCK) cells to quantify the following parameters: the number of cellular clusters in each image, the size of the clusters in terms of pixel counts, and the number of cells in each cluster. These parameters were used as measures of cell scattering and were compared with subjective assessments of scattering made by three experienced examiners.

RESULTS

The quantitative parameters correlated strongly to subjective assessments. The algorithm displayed a different concept of "clustering" than the examiners and consistently identified more clusters than did the examiners. There was close agreement in the number of cells counted. All three quantitative parameters correlated strongly to the subjective scattering scores, as follows: cluster count (r(s) = -0.765 to -0.789, P < 0.0001), cluster size in pixels (r(s) = 0.838 to 0.845, P < 0.0001), and cluster size in cells (r(s) = 0.758 to 0.804, P < 0.0001). The parameters were continuous, providing greater resolving power than ordinal subjective scores.

CONCLUSIONS

The findings confirmed that our algorithm reproduces the traditional classification of scattering with improved resolution, quantification, and objectivity.

A novel spectral microscope system: application in quantitative pathology

In this paper, a novel spectral microscope system is presented together with a method for the quantitative assessment of the uptake by histologic samples of stains used in pathology to label tissue features of diagnostic importance. The critical component of the microscope is a variable interference filter-based monochromator. The system is capable of performing real-time spectral imaging in a plurality of spectral bands and micro-spectroscopy in any image pixel, in the spectral range 400-1000 nm. The wavelength-tuning step is 2.4-2.6 nm, while the full-width at half maximum in each step is about 1.5% of the operating central wavelength. The developed system integrates algorithms and calibration procedures for the calculation of the stain-uptake by the tissue. The acquired spectra from both stained tissue and calibration stain solutions enable the calculation of the concentration maps of the stains, even if the latter are multiple and overlap spatially and spectrally. The system was used for the quantitative mapping of the expression of estrogen and progesterone receptors in breast cancer cells. In this particular case, model validation shows that although two stains are employed, capturing of their transmittance at more than ten wavelengths is required in order to obtain an acceptable accuracy. These findings highlight the need for the development and implementation of spectral microscopy in pathology and its potential to introduce novel more reliable diagnostic criteria.