Quantitative Morphological Assessment Research Articles

Quantitative morphological analysis of InP-based quantum dots reveals new insights into the complexity of shell growth.

The incorporation of quantum dots in display technology has fueled a renewed interest in InP-based quantum dots, but difficulty controlling the Zn chemistry during shelling has stymied thick, even ZnSe shell growth. The characteristic uneven, lobed morphology of Zn-based shells is difficult to assess qualitatively and measure through traditional methods. Here, we present a methodological study utilizing quantitative morphological analysis of InP/ZnSe quantum dots to analyze the impact of key shelling parameters on InP core passivation and shell epitaxy. We compare conventional hand-drawn measurements with an open-source semi-automated protocol to showcase the improved precision and speed of this method. Additionally, we find that quantitative morphological assessment can discern morphological trends in morphologies that qualitative methods cannot. In conjunction with ensemble fluorescence measurements, we find that changes to shelling parameters that promote even shell growth often do so at the cost of core homogeneity. These results indicate that the chemistry of passivating the core and promoting shell growth must be balanced carefully to maximize brightness while maintaining emission color-purity.

Abstract 14453: Deep Learning Enabled Measurement of Cardiac Sphericity Predicts Disease Risk Among Subjects With Normal Left Ventricular Size and Function

Introduction: Cardiac imaging primarily focuses on measurements of chamber size and function. Quantitative assessment of morphology may provide additional prognostic information. Left ventricle (LV) sphericity has been proposed as one metric but has not been studied in large populations and is poorly characterized in patients with normal LVs. We aimed to assess the clinical relevance and genetic drivers of sphericity among individuals with normal LV size and systolic function using deep learning enabled phenotyping of cardiac MRIs. Methods: The study cohort consisted of UK Biobank participants with normal LV ejection fraction, LV end-systolic, and end-diastolic volumes by MRI. A fully convolutional neural network was used to perform image segmentation of cardiac chambers. The main exposure was the LV sphericity index, defined as the ratio of short-axis to long-axis lengths of the smallest rectangle encompassing the LV in a 4-chamber view. Risk for incident outcomes were measured using Cox analysis. Genome-wide association study (GWAS) was performed using HAIL software with standard quality-control. Genetic correlations were measured using linkage-disequilibrium score regression. Causal inference was performed using two-sample Mendelian randomization (MR). Results: We identified 38,897 subjects with normal LV volumes and ejection fraction. Mean age was 55 ± 8, and 54% were female. After adjusting for age, sex, BMI, hypertension, and pulse-rate, a 1 standard deviation increase in sphericity index was associated with increased risk of atrial fibrillation (HR 1.31, 95% CI 1.23-1.38, P <2x10 -16 ) and cardiomyopathy (HR 1.62, 95% CI 1.29-2.02, P 2.4x10 -5 ). GWAS of sphericity index identified 4 loci at genome-wide significance, with 3 candidate genes previously implicated in cardiac development and conduction. Sphericity index showed a genetic correlation with cardiomyopathy ( rg 0.42, P 0.01) but not with atrial fibrillation ( rg 0.04, P 0.5). Bidirectional MR analyses supported cardiomyopathy as being causal for sphericity but not the reverse. Conclusion LV sphericity in subjects with normal size and function is genetically mediated and may reflect subclinical manifestations of cardiomyopathic risk prior to LV remodeling by standard measures.

μMatch: 3D Shape Correspondence for Biological Image Data

Modern microscopy technologies allow imaging biological objects in 3D over a wide range of spatial and temporal scales, opening the way for a quantitative assessment of morphology. However, establishing a correspondence between objects to be compared, a first necessary step of most shape analysis workflows, remains challenging for soft-tissue objects without striking features allowing them to be landmarked. To address this issue, we introduce the μMatch 3D shape correspondence pipeline. μMatch implements a state-of-the-art correspondence algorithm initially developed for computer graphics and packages it in a streamlined pipeline including tools to carry out all steps from input data pre-processing to classical shape analysis routines. Importantly, μMatch does not require any landmarks on the object surface and establishes correspondence in a fully automated manner. Our open-source method is implemented in Python and can be used to process collections of objects described as triangular meshes. We quantitatively assess the validity of μMatch relying on a well-known benchmark dataset and further demonstrate its reliability by reproducing published results previously obtained through manual landmarking.

Application of neural network for morphological assessment of revascularized autograft remodeling at the stage of implant placement in jaw defects

Relevance. The study examines the possibility of using a mathematic model of an artificial neural network (ANN) for comparative quantitative morphological assessment of revascularized autograft remodeling after reconstructive surgery in patients with jaw defects.Materials and methods. Jawbone biopsies of 30 patients were histologically examined during the implant placement stage, 6, 9, 12 months after the reconstructive surgery with a revascularized fibular graft. Histology images were analyzed using a mathematic model created on the basis of GoogLeNet and trained on morphological images of bone maturation. Histology slides were digitized by a scanning microscope Leica SC2 and streamed through the neural network model. Results. During the follow-up period, jaw defect areas demonstrated relatively mature bone tissue formation with various intensity rates of remodeling and maturation of the newly-formed bone. At that, the results of the descriptive histology were consistent with the quantitative results of the ANN mathematic model, created on the basis of the softwarehardware system developed by the authors. The confirmed significance level is 95% or higher.Conclusion. Pathomorphological data of biopsies were studied using an ANN mathematical model, built on a softwarehardware system, which allowed analyzing all microscope fields of view of a histological slide, bypassing random samples, as well as the evaluation by a pathologist of individual microscope fields of view, to exclude the possibility of unrepresentative sampling and the influence of human factor, which significantly increases the significance of the received results.

Characterization of white matter branching in human cerebella: quantitative morphological assessment and fractal analysis of skeletonized MR images

Introduction: The aim of the present study was to investigate branching characteristics of the human cerebellar white matter by the means of findings obtained from the quantitative morphological assessment and fractal analysis of the skeletonized MR images of the human cerebellum.
 Methods: Thirty individuals with no apparent brain pathology (15 males and 15 females, ranging from 18 - 30 years of age) participated in this study. Their normal T2-weighted MR images of the cerebellar vermis (midsagittal plane) were examined. The skeletonizing procedure and subsequent quantitative morphological assessment of the acquired skeletonized MR images were performed. The following parameters were determined: the number of branches, the number of junctions, the amount of end-point voxels, junction voxels and slab voxels, the average and maximum branch lengths, the longest-shortest patch length, and the number of triple and quadruple points. Additionally, the individual branches of the obtained digital skeletons of the cerebellar white matter were examined and the following parameters were assessed: branch length variability, Euclidean distance, and branch length/Euclidean distance ratio. A fractal analysis was performed using the box counting method prior to and after the MR image skeletonizing procedure. The values of the fractal dimensions (FD) of both skeletonized and non-skeletonized MR images were calculated.
 Results: It was established that the cerebella, which had the maximum values of the FD, possessed a large number of small branches approximately equal in length and which were connected by numerous junctions, forming numerous endpoints. Those cerebella, which had higher values of the average branch length and greater branch length variability, showed lower values of the FD. The key characteristics of the digital skeleton that determined the values of the FD of the cerebellum and its skeletonized MR images were the number of branches and the number of junctions that had the strongest correlational relationships with the FD of the skeletonized MR images. We submitted a proposition to consider the number of branches and amount of junctions as a diagnostic criterion in the determination of normal values of the FD.
 Conclusions: The obtained data can be used as diagnostic criteria in assessment of the morphofunctional state of the cerebellum using magnetic resonance imaging (MRI) technique.

Quantitative Morphometric Analysis of Anatomical Landmarks Involved in Bilateral Sagittal Split Osteotomy in Different Skeletal Malocclusions Using Cone-Beam Computed Tomography.

To assess and compare the anatomical landmarks involved in bilateral sagittal split osteotomy (BSSO) in different skeletal malocclusions quantitatively using cone-beam computed tomography (CBCT). This retrospective study evaluated 63 CBCT scans of the three malocclusion classes (n = 21). Twenty-one quantitative variables were measured and compared between different malocclusion classes. One-way ANOVA, Welch test, Kruskal Wallis test and the Mann-Whitney test with Bonferroni adjustment were used for data analysis. The level of significance was set at ≤0.05. The patients had a mean age of 26.35 years (range 18-58 years). The width of the lateral cortex in the posterior third (T1-P) of ramus in the left side, and the mean value in the right and left sides were significantly different between different classes of malocclusion (P = 0.049) such that class II patients had significantly thinner lateral cortex. No other significant differences were noted between different malocclusion classes in other variables. The quantitative morphological assessment of the mandible in BSSO of different malocclusion classes did not reveal significant differences. There is no superiority in the dimensions of discussed landmarks involved in BSSO among different malocclusion classes. So the risk or the safety of this kind of surgery is similar for these classes. Thus, diagnostic preoperative workup by CBCT is imperative for selection of a surgical approach with minimal postoperative complications.

Quantitative assessment of morphology and sub-cellular changes in macrophages and trophoblasts during inflammation.

In pregnancy during an inflammatory condition, macrophages present at the feto-maternal junction release an increased amount of nitric oxide (NO) and pro-inflammatory cytokines such as TNF-α and INF-γ, which can disturb the trophoblast functions and pregnancy outcome. Measurement of the cellular and sub-cellular morphological modifications associated with inflammatory responses are important in order to quantify the extent of trophoblast dysfunction for clinical implication. With this motivation, we investigated morphological, cellular and sub-cellular changes in externally inflamed RAW264.7 (macrophage) and HTR-8/SVneo (trophoblast) using structured illumination microscopy (SIM) and quantitative phase microscopy (QPM). We monitored the production of NO, changes in cell membrane and mitochondrial structure of macrophages and trophoblasts when exposed to different concentrations of pro-inflammatory agents (LPS and TNF-α). In vitro NO production by LPS-induced macrophages increased 22-fold as compared to controls, whereas no significant NO production was seen after the TNF-α challenge. Under similar conditions as with macrophages, trophoblasts did not produce NO following either LPS or the TNF-α challenge. Super-resolution SIM imaging showed changes in the morphology of mitochondria and the plasma membrane in macrophages following the LPS challenge and in trophoblasts following the TNF-α challenge. Label-free QPM showed a decrease in the optical thickness of the LPS-challenged macrophages while TNF-α having no effect. The vice-versa is observed for the trophoblasts. We further exploited machine learning approaches on a QPM dataset to detect and to classify the inflammation with an accuracy of 99.9% for LPS-challenged macrophages and 98.3% for TNF-α-challenged trophoblasts. We believe that the multi-modal advanced microscopy methodologies coupled with machine learning approach could be a potential way for early detection of inflammation.

Metabolomic signature of type 1 diabetes-induced sensory loss and nerve damage in diabetic neuropathy.

Diabetic-induced peripheral neuropathy (DPN) is a highly complex and frequent diabetic late complication, which is manifested by prolonged hyperglycemia. However, the molecular mechanisms underlying the pathophysiology of nerve damage and sensory loss remain largely unclear. Recently, alteration in metabolic flux has gained attention as a basis for organ damage in diabetes; however, peripheral sensory neurons have not been adequately analyzed with respect to metabolic dysfunction. In the present study, we attempted to delineate the sequence of event occurring in alteration of metabolic pathways in relation to nerve damage and sensory loss. C57Bl6/j wild-type mice were analyzed longitudinally up to 22weeks in the streptozotocin (STZ) model of type 1 diabetes. The progression of DPN was investigated by behavioral measurements of sensitivity to thermal and mechanical stimuli and quantitative morphological assessment of intraepidermal nerve fiber density. We employed a mass spectrometry-based screen to address alterations in levels of metabolites in peripheral sciatic nerve and amino acids in serum over several months post-STZ administration to elucidate metabolic dysfunction longitudinally in relation to sensory dysfunction. Although hyperglycemia and body weight changes occurred early, sensory loss and reduced intraepithelial branching of nociceptive nerves were only evident at 22weeks post-STZ. The longitudinal metabolites screen in peripheral nerves demonstrated that compared with buffer-injected age-matched control mice, mice at 12 and 22weeks post-STZ showed an early impairment the tricaoboxylic acid (TCA cycle), which is the main pathway of carbohydrate metabolism leading to energy generation. We found that levels of citric acid, ketoglutaric acid (2 KG), succinic acid, fumaric acid, and malic acid were observed to be significantly reduced in sciatic nerve at 22weeks post-STZ. In addition, we also found the increase in levels of sorbitol and L-lactate in peripheral nerve from 12weeks post-STZ injection. Amino acid screen in serum showed that the amino acids valine (Val), isoleucine (Ile), and leucine (Leu), grouped together as BCAA, increased more than twofold from 12weeks post-STZ. Similarly, the levels of tyrosine (Tyr), asparagine (Asn), serine (Ser), histidine (His), alanine (Ala), and proline (Pro) showed progressive increase with progression of diabetes. Our results indicate that the impaired TCA cycle metabolites in peripheral nerve are the primary cause of shunting metabolic substrate to compensatory pathways, which leads to sensory nerve fiber loss in skin and contribute to onset and progression of peripheral neuropathy.

Right Ventricular Pressure Overload and Pathophysiology of Growing Porcine Biomodel.

The primary objective was to create a clinically relevant model of right ventricular hypertension and to study right ventricular myocardial pathophysiology in growing organism. The secondary objective was to analyse the effect of oral enoximone (phosphodiesterase inhibitor) therapy on right ventricular haemodynamic parameters and myocardial changes in biomodel of right ventricular hypertension. The study included a total of 12 piglets of 42days of age. Under general anaesthesia, pulmonary artery banding (PAB) was performed surgically to constrict the main pulmonary artery to about 70-80% of its original dimension. The study presented two groups of animals labelled C (control animals with PAB; n=8) and E (animals with PAB and oral administration of enoximone; n=4). Direct pressure and echocardiographic measurements were taken during operation (time-1), and again at 40days after surgery (time-2). The animals were killed, and tissue samples from the heart chambers were collected for quantitative morphological assessment. Statistical analysis was performed on all acquired data. At time-2, the median weight of animals doubled and the median systolic pressure gradient across the PAB increased (46.59±15.87mmHg vs. 20.29±5.76mmHg; p<0.001). Changes in haemodynamic parameters were compatible with right ventricular diastolic dysfunction in all the animals. Apoptosis, tissue proliferation and fibrosis were identified in all the myocardial tissue samples. Right ventricular pressure overload leads to increased apoptosis of cardiac myocytes, proliferation and myocardial fibrosis. Our study did not show evidence of haemodynamic benefit or myocardial protective effect of oral enoximone treatment.

Inhibition of postsurgical adhesions by methylene blue-loaded nanofibers versus cast film matrices

In the quest for barrier membranes for the prevention of post-surgical tissue adhesions, polymer matrices may provide a platform of biomaterials with versatile properties. However, the relationship between the anti-adhesion effects of different polymer matrices and their physicochemical and structural properties is not yet adequately understood. In a preclinical study using a rat cecum model, we directly compared the anti-adhesion potential of polyhydroxybutyrate (PHB) electrospun nanofibrous versus cast film matrices loaded with methylene blue (MB) as antioxidant adhesion inhibitor. PHB retained MB presumably forming MB-bioactivated matrices. In the preclinical study, quantitative morphologic assessment in addition to histopathologic and SEM examinations 14 days post-surgery indicated that plain PHB NFs and MB-PHB NFs, moderately enhanced cecal wall healing and inhibited adhesion formation. In contrast, reshaping PHB as cast films, significantly enhanced healing, reduced adhesion bands and prevented inter-visceral adhesions. Cast films also inhibited tissue attachment to the matrix recovered 14 days post-surgery. Both PHB matrix types reduced tissue inflammation. Despite tissue anti-adhesion potential of individual matrix components, modulation of the micro-architectural properties generated polymer barriers with varying tissue anti-adhesion and healing potentials, the MB-loaded cast film achieving the best outcome.

Quantitative assessment of morphology, T1ρ, and T2 of shoulder cartilage using MRI.

The aim of this study was to assess the feasibility of quantifying shoulder cartilage morphology and relaxometry in a clinically feasible scan time comparing different pulse sequences and assessing their reproducibility at 3 Tesla. Three pulse sequences were compared for morphological assessments of shoulder cartilage thickness and volume (SPGR, MERGE, FIESTA), while a combined T1ρ-T2 sequence was optimized for relaxometry measurements. The shoulders of six healthy subjects were scanned twice with repositioning, and the cartilage was segmented and quantified. The degree of agreement between the three morphological sequences was assessed using Bland-Altman plots, while the morphological and relaxometry reproducibility were assessed with root-mean-square coefficients of variation (RMS-CVs) RESULTS: Bland-Altman plots indicated good levels of agreement between the morphological assessments of the three sequences. The reproducibility of morphological assessments yielded RMS-CVs between 4.0 and 17.7%. All sequences correlated highly (R > 0.9) for morphologic assessments with no statistically significant differences. For relaxometry assessments of humeral cartilage, RMS-CVs of 6.4 and 10.6% were found for T1ρ and T2, respectively. The assessment of both cartilage morphology and relaxometry is feasible in the shoulder with SPGR, humeral head, and T1ρ being the more reproducible morphological sequence, anatomic region, and quantitative sequence, respectively. • The thin cartilage morphology can be assessed in the shoulder in vivo. • Non-invasive biochemical assessment of shoulder cartilage is feasible in vivo using MRI.

Development of a quantitative morphological assessment of toxicant-treated zebrafish larvae using brightfield imaging and high-content analysis.

One of the rate-limiting procedures in a developmental zebrafish screen is the morphological assessment of each larva. Most researchers opt for a time-consuming, structured visual assessment by trained human observer(s). The present studies were designed to develop a more objective, accurate and rapid method for screening zebrafish for dysmorphology. Instead of the very detailed human assessment, we have developed the computational malformation index, which combines the use of high-content imaging with a very brief human visual assessment. Each larva was quickly assessed by a human observer (basic visual assessment), killed, fixed and assessed for dysmorphology with the Zebratox V4 BioApplication using the Cellomics® ArrayScan® V(TI) high-content image analysis platform. The basic visual assessment adds in-life parameters, and the high-content analysis assesses each individual larva for various features (total area, width, spine length, head-tail length, length-width ratio, perimeter-area ratio). In developing the computational malformation index, a training set of hundreds of embryos treated with hundreds of chemicals were visually assessed using the basic or detailed method. In the second phase, we assessed both the stability of these high-content measurements and its performance using a test set of zebrafish treated with a dose range of two reference chemicals (trans-retinoic acid or cadmium). We found the measures were stable for at least 1 week and comparison of these automated measures to detailed visual inspection of the larvae showed excellent congruence. Our computational malformation index provides an objective manner for rapid phenotypic brightfield assessment of individual larva in a developmental zebrafish assay. Copyright © 2016 John Wiley & Sons, Ltd.

Shapes of Discoid Intracellular Compartments with Small Relative Volumes

A prominent feature of many intracellular compartments is a large membrane surface area relative to their luminal volume, i.e., the small relative volume. In this study we present a theoretical analysis of discoid membrane compartments with a small relative volume and then compare the theoretical results to quantitative morphological assessment of fusiform vesicles in urinary bladder umbrella cells. Specifically, we employ three established extensions of the standard approach to lipid membrane shape calculation and determine the shapes that could be expected according to three scenarios of membrane shaping: membrane adhesion in the central discoid part, curvature driven lateral segregation of membrane constituents, and existence of stiffer membrane regions, e.g., support by protein scaffolds. The main characteristics of each scenario are analyzed. The results indicate that even though all three scenarios can lead to similar shapes, there are values of model parameters that yield qualitatively distinctive shapes. Consequently, a distinctive shape of an intracellular compartment may reveal its membrane shaping mechanism and the membrane structure. The observed shapes of fusiform vesicles fall into two qualitatively different classes, yet they are all consistent with the theoretical results and the current understanding of their structure and function.

Quantitative morphological assessment reveals neuronal and glial deficits in hippocampus after a brief subtoxic exposure to chlorpyrifos in neonatal rats

Neurochemical and behavioral studies indicate that the widely used organophosphorus insecticide, chlorpyrifos (CPF), evokes neurobehavioral teratogenicity with a wide window of vulnerability, ranging from embryonic life through postnatal development. Few studies have detailed morphological damage that corresponds to the operational deficits. We administered 5 mg/kg of CPF sc daily on postnatal days (PN) 11–14, a regimen that is devoid of systemic toxicity, but that elicits long-term cognitive impairment and disruption of cholinergic, catecholaminergic, and serotonergic synaptic function. On PN15 and 20, we conducted quantitative morphologic examinations of neurons and glia in CA1, CA3, and dentate gyrus regions of the hippocampus. Although hippocampal morphology after CPF exposure was normal on gross observation, morphometric analysis revealed a significant overall reduction in the total number of neurons and glia. Superimposed on this basic effect, CPF elicited a delayed-onset increase in the neuron/glia ratio that emerged by PN20, connoting selective gliotoxicity. The alterations in cell numbers were accompanied by significant perikaryal swelling and by enhanced development of astrocytic processes. Layer thickness also showed delayed-onset effects of CPF, with thinning of the CA1 and CA3 layers and enlargement of the dentate gyrus. Our results indicate that there are subtle morphological changes in the juvenile rat brain after neonatal CPF exposure that are detectable only with quantitative analysis and that correlate with regional and cell-specific targets identified earlier in neurochemical studies. The simultaneous targeting of neurons and glia by CPF is likely to play an important role in its developmental neurotoxicant effects.

On sampling and sampling errors in histomorphometry of peripheral nerve fibers

Histomorphometrical assessment of regenerated peripheral nerves is a very common goal of many studies in experimental microsurgery. In this paper, the main critical issues in nerve fiber sampling for quantitative morphological assessment are addressed. The equal opportunity rule, i.e., the basic paradigm of random sampling, is described, together with an explanation of how sampling errors, in the selection of histologic fields and of the nerve fibers inside them, can produce a bias in quantitative estimates. Finally, some practical suggestions on how to cope with the most common sampling errors are provided, in order to help researchers obtain reliable histomorphometrical data on peripheral nerve fibers.

Effects of prolonged exposure to nanomolar concentrations of methylmercury on voltage-sensitive sodium and calcium currents in PC12 cells

The neurotoxicant methylmercury (CH 3Hg +) inhibits voltage-sensitive Na + and Ca 2+ currents in neuronal preparations following acute, in vitro, exposure. In the present study, effects on voltage-sensitive Na + ( I Na) and Ca 2+ ( I Ca) currents in pheochromocytoma (PC12) cells were examined following prolonged exposure to CH 3Hg +. When PC12 cells cultured in the presence of nerve growth factor (NGF) for 7 days (‘primed’) were replated in the presence of NGF and 30 nM CH 3Hg +, I Ca, but not I Na, amplitude was reduced (29%) significantly ∼24 h later. Quantitative assessment of morphology indicated that this ∼24 h exposure to CH 3Hg + significantly reduced neurite length. The N-type voltage-sensitive Ca 2+ channel (VSCC) antagonist ω-conotoxin GVIA (500 pM) was without significant effect on current amplitude or morphology in this exposure protocol. When undifferentiated cells were cultured in the presence of NGF and 10 nM CH 3Hg + for 6 days, I Ca and I Na amplitude were reduced by 36 and 52%, respectively. I Ca at the end of a 150 ms test pulse was also reduced by 40% in CH 3Hg +-treated cells. Thus, both inactivating and non-inactivating I Ca were reduced equally. There was no change in [ 3H]saxitoxin or ω-[ 125I]conotoxin GVIA binding, nor were there any morphological alterations in cells treated with CH 3Hg + for 6 days. Omega-conotoxin GVIA (500 pM, 6 days), reduced significantly I Ca, but not I Na, but was without effect on morphology. These results demonstrate that prolonged exposure to low concentrations of CH 3Hg + reduces cationic currents in differentiating PC12 cells, but that current reduction is not always associated with morphological alteration.

Isquemia e reperfusão experimental no cólon menor eqüino

Sob anestesia geral, com constante controle sobre a pressão arterial e a saturação de oxigênio da hemoglobina arterial, realizou-se celiotomia em 12 eqüinos. No cólon menor exposto foram demarcados três segmentos de 25cm, separados entre si por igual distância. Dois desses segmentos foram submetidos à isquemia arteriovenosa completa por 90 (grupo A) ou 180 minutos (grupo B). O terceiro segmento foi o grupo-controle. Amostras para histopatologia foram colhidas ao final dos períodos de isquemia e após 90 e 180 minutos de reperfusão no grupo A e após 90 minutos de reperfusão no grupo B. No controle, colheram-se amostras no início e final do procedimento. Avaliaram-se as lesões produzidas na mucosa e na submucosa pelos métodos semiquantitativos-escores para desprendimento de epitélio, edema, hemorragia e infiltrado de neutrófilos, e pelos quantitativos-porcentagem de perda de mucosa (PM) e razão cripta:interstício (C:I). As lesões isquêmicas foram mais intensas no grupo B do que no A para PM, C:I, desprendimento de epitélio e edema de mucosa. As amostras obtidas após a reperfusão revelaram que houve agravamento na PM, C:I, desprendimento de epitélio e edema de submucosa em ambos os grupos. Concluiu-se que a reperfusão agravou as lesões isquêmicas no cólon menor e que o modelo proposto é viável para produção dessas lesões.

Quantitative Morphologic Assessment of Thoracolumbar Vertebrae in Korean Women by Morphometric X-rayAbsorptiometry

Purpose : To compare the accuracy of lateral radiography of the spine with that of morphometric X-rayabsorptiometry(MXA) in vertebral morphometry, and to evaluate normal vertebral morphometry using MXA in Koreanwomen. Materials and Methods : A spine phantom was constructed using copper pipe. Its anterior and posteriorheights were measured directly, with lateral radiographs and with MXA, and the values thus obtained were compared.Inter -and intra -observer variations were evaluated by three radiologists. The vertebral morphometry of 30 youngwomen volunteers were imaged using thoracic and lumbar lateral radiographs and MXA, and analysis included themeasurement of anterior and posterior heights from T4 to L4. We also obtained the vertebral morphometry of 200normal Korean women who underwent MXA between March 1995 and February 1996, though those with osteoporosis andother spinal lesions were excluded from this study. Thoracolumbar vertebral indexes were statistically correlatedwith age, height and bone mineral Results : There were no statistically significant differences in the heights ofspine phantom measured by MXA compared with actual size (mean difference=0.28mm). Simple radiographs weremagnified by 23.7% at a phantom-table distance of 15cm, and distortion ranged from 0.5% to 22.5%, depending onphantom level and phantom-table distance. In the study of volunteers, the magnification rate between a simpleradiograph and MXA was about 26.6%. Anterior height increased progressively from the thoracic to the lumbar spine,though posterior height peaked at L2, and L4 was less than anterior height. In Korean women, indices of vertebralmorphometry decreased significantly with aging, with the most prominent decrease occurring during the seventhdecade. The mineral density of spinal bone decreased markedly after the sixth decade. Conclusion : Radiographsshowed more magnification and distortion than did MXA, though between morphometric X-ray absorptiometry (MXA) andactual size, there was no significant difference. The vertebral morphometric indices of Korean women and referredbone mineral density may provide useful data for determining and evaluating follow-up changes in spinalmorphology.

A quantitative morphological assessment of the effect of lidoflazine and deferoxamine therapy on global brain ischaemia.

The effect of the combination of two drugs, i.e. lidoflazine (a calcium antagonist), and deferoxamine (an iron chelator) was evaluated following 15 min global brain ischaemia (GBI) and reperfusion in dogs in a randomized blind study. GBI was produced by complete cardiac arrest of 15 min duration. Histopathological analysis performed on in situ fixed brains 40 h post-resuscitation revealed diffuse microhaemorrhages in the control group. These were noted rarely in the treatment group, the mean value of foci of microhaemorrhages/20 low power fields (LPF) being 5.2 in the treatment group versus 28 in the control group (p less than 0.001). Diffuse coagulative necrosis of neurons (ischaemic cell change) in the cerebral cortex, especially lamina 3, hippocampus, striatum, brain stem and cerebellum was present in all cases. Quantitation of the degree of cellular damage obtained by counting the number of anoxic neurons (in consistent regions of the brain) with the use of an image analysis system, revealed no significant difference between the 2 groups. The mean percentages of the ischaemic neurons in the control group in the various areas studied were: parietal cortex, 22.25; hippocampus, 50.37 and cerebellum (Purkinje cells), 66.75; and in the treatment group 25.3, 55.04 and 70.6 respectively. Thus, the lidoflazine-deferoxamine regimen significantly reduced the incidence of microhaemorrhages in the brain, but it did not have any protective effect against anoxic neuronal injury 40 h post-ischaemia in this experimental model of GBI of 15 min duration.

Effect of flunarizine on global brain ischemia in the dog: A quantitative morphologic assessment

The effects of flunarizine, a calcium antagonist, were evaluated in an experimental model of global brain ischemia produced by 15 min of cardiac arrest followed by resuscitation and reperfusion. One group of dogs received flunarizine (0.1 mg/kg intravenously during a 10-min period) at the onset of resuscitation. Another group of dogs underwent cardiac arrest, resuscitation, and reperfusion but did not receive flunarizine. A third group served as nonischemic control. In situ-fixed brains of all animals (nonischemic controls and the postischemic dogs after 8 h of reperfusion) were examined for anoxic ischemic injury. Quantitation of the ischemic neurons was carried out in parietal cortex, hippocampus, and cerebellum by using an image analysis system. Significant difference in the number of necrotic neurons between the flunarizine-treated group and the ischemic controls was noted in the hippocampus only; the mean percentage of necrotic neurons in the two groups being 14.8 ± 9.6 and 29.3 ± 12.1, respectively ( P < 0.05). These results indicate that flunarizine has an ameliorating effect on neuronal injury in the hippocampus that follows cardiac arrest in this experimental model of global brain ischemia. However, flunarizine was not found to be effective in reducing the ischemic neuronal damage in the cortex or the cerebellum.