Seven retinal specializations in the tubular eye of the deep-sea pearleye, Scopelarchus michaelsarsi: A case study in visual optimization

The deep-sea pearleye, Scopelarchus michaelsarsi (Scopelarchidae) is a mesopelagic teleost with asymmetric or tubular eyes. The main retina subtends a large dorsal binocular field, while the accessory retina subtends a restricted monocular field of lateral visual space. Ocular specializations to increase the lateral visual field include an oblique pupil and a corneal lens pad. A detailed morphological and topographic study of the photoreceptors and retinal ganglion cells reveals seven specializations: a centronasal region of the main retina with ungrouped rod-like photoreceptors overlying a retinal tapetum; a region of high ganglion cell density (area centralis of 56.1x10(3) cells per mm(2)) in the centrolateral region of the main retina; a centrotemporal region of the main retina with grouped rod-like photoreceptors; a region (area giganto cellularis) of large (32.2+/-5.6 mu m(2)), alpha-like ganglion cells arranged in a regular array (nearest neighbour distance 53.5+/-9.3 mu m with a conformity ratio of 5.8) in the temporal main retina; an accessory retina with grouped rod-like photoreceptors; a nasotemporal band of a mixture of rod-and cone-like photoreceptors restricted to the ventral accessory retina; and a retinal diverticulum comprised of a ventral region of differentiated accessory retina located medial to the optic nerve head. Retrograde labelling from the optic nerve with DiI shows that approximately 14% of the cells in the ganglion cell layer of the main retina are displaced amacrine cells at 1.5 mm eccentricity. Cryosectioning of the tubular eye confirms Matthiessen's ratio (2.59), and calculations of the spatial resolving power suggests that the function of the area centralis (7.4 cycles per degree/8.1 minutes of are) and the cohort of temporal alpha-like ganglion cells (0.85 cycles per degree/70.6 minutes of are) in the main retina may be different. Low summation ratios in these various retinal zones suggests that each zone may mediate distinct visual tasks in a certain region of the visual field by optimizing sensitivity and/or resolving power.

Morphological and electrophysiological properties of principal neurons in the rat lateral amygdala in vitro

In this study, we characterize the electrophysiological and morphological properties of spiny principal neurons in the rat lateral amygdala using whole cell recordings in acute brain slices. These neurons exhibited a range of firing properties in response to prolonged current injection. Responses varied from cells that showed full spike frequency adaptation, spiking three to five times, to those that showed no adaptation. The differences in firing patterns were largely explained by the amplitude of the afterhyperpolarization (AHP) that followed spike trains. Cells that showed full spike frequency adaptation had large amplitude slow AHPs, whereas cells that discharged tonically had slow AHPs of much smaller amplitude. During spike trains, all cells showed a similar broadening of their action potentials. Biocytin-filled neurons showed a range of pyramidal-like morphologies, differed in dendritic complexity, had spiny dendrites, and differed in the degree to which they clearly exhibited apical versus basal dendrites. Quantitative analysis revealed no association between cell morphology and firing properties. We conclude that the discharge properties of neurons in the lateral nucleus, in response to somatic current injections, are determined by the differential distribution of ionic conductances rather than through mechanisms that rely on cell morphology.

Micromorphological study of slumping in a hardsetting seedbed under various wetting conditions

Slumping of hardsetting seedbeds upon wetting has not been extensively studied despite the likelihood that it determines the physical properties after drying. Slumping results from processes similar to those involved in crusting except that overburden pressure can dominate rather than rainfall kinetic energy. Only a few studies have dealt with the morphological description of slumping. To simulate different climatic and management conditions, repacked seedbeds of a hardsetting sandy-loam soil were subjected to a range of wetting conditions, e.g. capillary rise, immersion, and rainfall simulation. Slumping processes were characterized using qualitative and quantitative micromorphological observations of polished blocks and thin sections from resin-impregnated samples. A morphogenetical framework was proposed to help description of the complex associations of processes which can lead to structural collapse (crusting and slumping) on wetting. Three main stages were considered, i.e. aggregate disruption or abrasion, relocation of the released material, and compaction. In the hardsetting material studied here, structural collapse under slow wetting occurred at the bottom of cores due to aggregate coalescence under overburden pressure. Coalescence required aggregate cohesion being reduced by microcracking; therefore, it differed from the coalescence previously described in unstable silty loam soils where microcracking was not necessary for aggregates to coalesce. Macroporosity decreased most strongly under fast wetting due to physical dispersion and aggregate breakdown. Under simulated rainfall, compaction by raindrops could not be distinguish from aggregate breakdown. The role of overburden pressure and of rainfall kinetic energy remains to be stated; new data are required including measurement of total porosity in the initial, wet, and dry states. (C) 2003 Elsevier B.V. All rights reserved.

Soil morphological control on saline and freshwater lake hydrogeochemistry in the Pantanal of Nhecolandia, Brazil

Joint pedological, geochemical, hydrological and geophysical investigations were performed to study the coexistence or saline and freshwater lakes in close proximity and similar climatic conditions in the Nhecolandia region, Pantanal wetlands in Brazil. The saline lakes are concentrically surrounded by green sandy loam horizons, which cause differential hydrological regimes. Mg-calcite, K-silicates, and amorphous silica precipitate in the soil cover, whereas Mg-silicates and more soluble Na-carbonates are concentrated in the topsoil along the shore of the saline lake. In saline solutions, some minor elements (As, Se) reach values above the water quality recommendations, whereas others are controlled and incorporated in solid phases (Ba, Sr). Locally, the destruction of the sandy loam horizons generates very acidic soil solution (pH similar to 3.5) through a process not yet understood. The soil distributions indicate that some freshwater lakes are former saline lakes. They are invaded by freshwater after destruction of the sandy loam green horizons, then the freshwater becomes enriched in K(+), SO(4)(2-), Fe, Al, and a stream of minor and trace elements. The formation of these green sandy loam horizons in the saline environment and their destruction in the non-saline one emphasizes the dynamic nature of this environment (C) 2008 Elsevier B.V. All rights reserved.

Small airway remodeling in acute respiratory distress syndrome: a study in autopsy lung tissue

Introduction: Airway dysfunction in patients with the Acute Respiratory Distress Syndrome (ARDS) is evidenced by expiratory flow limitation and dynamic hyperinflation. These functional alterations have been attributed to closure/obstruction of small airways. Airway morphological changes have been reported in experimental models of acute lung injury, characterized by epithelial necrosis and denudation in distal airways. To date, however, no study has focused on the morphological airway changes in lungs from human subjects with ARDS. The aim of this study is to evaluate structural and inflammatory changes in distal airways in ARDS patients. Methods: We retrospectively studied autopsy lung tissue from subjects who died with ARDS and from control subjects who died of non pulmonary causes. Using image analysis, we quantified the extension of epithelial changes (normal, abnormal and denudated epithelium expressed as percentages of the total epithelium length), bronchiolar inflammation, airway wall thickness, and extracellular matrix (ECM) protein content in distal airways. The Student`s t test or the Mann-Whitney test was used to compare data between the ARDS and control groups. Bonferroni adjustments were used for multiple tests. The association between morphological and clinical data was analyzed by Pearson rank test. Results: Thirty-one ARDS patients (A: PaO(2)/FiO(2) <= 200, 45 +/- 14 years, 16 males) and 11 controls (C:52 +/- 16 years, 7 males) were included in the study. ARDS airways showed a shorter extension of normal epithelium (A:32.9 +/- 27.2%, C:76.7 +/- 32.7%, P < 0.001), a larger extension of epithelium denudation (A:52.6 +/- 35.2%, C:21.8 +/- 32.1%, P < 0.01), increased airway inflammation (A:1(3), C:0(1), P = 0.03), higher airway wall thickness (A:138.7 +/- 54.3 mu m, C:86.4 +/- 33.3 mu m, P < 0.01), and higher airway content of collagen I, fibronectin, versican and matrix metalloproteinase-9 (MMP-9) compared to controls (P = 0.03). The extension of normal epithelium showed a positive correlation with PaO(2)/FiO(2) (r(2) = 0.34; P = 0.02) and a negative correlation with plateau pressure (r(2) = 0.27; P = 0.04). The extension of denuded epithelium showed a negative correlation with PaO(2)/FiO(2) (r(2) = 0.27; P = 0.04). Conclusions: Structural changes in small airways of patients with ARDS were characterized by epithelial denudation, inflammation and airway wall thickening with ECM remodeling. These changes are likely to contribute to functional airway changes in patients with ARDS.

A method to immunolabel rodent spinal cord neurons and glia for molecular study in specific laser microdissected cells involved in neurodegenerative disorders

Neuron-glia interaction is involved in physiological function of neurons, however, recent evidences have suggested glial cells as participants in neurotoxic and neurotrophic mechanisms of neurodegenerative/neuroregenerative processes. Laser microdissection offers a unique opportunity to study molecular regulation in specific immunolabeled cell types. However, an adequate protocol to allow morphological and molecular analysis of rodent spinal cord astrocyte, microglia and motoneurons remains a big challenge. In this paper we present a quick method to immunolabel those cells in flash frozen sections to be used in molecular biology analyses after laser microdissection and pressure catapulting.

Classification model based on Raman spectra of selected morphological and biochemical tissue constituents for identification of atherosclerosis in human coronary arteries

This study presents the results of Raman spectroscopy applied to the classification of arterial tissue based on a simplified model using basal morphological and biochemical information extracted from the Raman spectra of arteries. The Raman spectrograph uses an 830-nm diode laser, imaging spectrograph, and a CCD camera. A total of 111 Raman spectra from arterial fragments were used to develop the model, and those spectra were compared to the spectra of collagen, fat cells, smooth muscle cells, calcification, and cholesterol in a linear fit model. Non-atherosclerotic (NA), fatty and fibrous-fatty atherosclerotic plaques (A) and calcified (C) arteries exhibited different spectral signatures related to different morphological structures presented in each tissue type. Discriminant analysis based on Mahalanobis distance was employed to classify the tissue type with respect to the relative intensity of each compound. This model was subsequently tested prospectively in a set of 55 spectra. The simplified diagnostic model showed that cholesterol, collagen, and adipocytes were the tissue constituents that gave the best classification capability and that those changes were correlated to histopathology. The simplified model, using spectra obtained from a few tissue morphological and biochemical constituents, showed feasibility by using a small amount of variables, easily extracted from gross samples.

Small Airway Remodeling in Idiopathic Interstitial Pneumonias: A Pathological Study

Background: Few studies have addressed small airway (SA) histopathological changes and their possible role in the remodeling process in idiopathic interstitial pneumonias. Objectives: To study morphological, morphometrical and immunohistochemical features of SA in idiopathic pulmonary fibrosis (usual interstitial pneumonia, UIP) and nonspecific interstitial pneumonia (NSIP). Methods: We analyzed SA pathology in lung biopsies from 29 patients with UIP and 8 with NSIP. Biopsies were compared with lung tissue from 13 patients with constrictive bronchiolitis (CB) as positive controls and 10 normal autopsied control lungs. We semi-quantitatively analyzed SA structure, inflammation, architectural features and the bronchiolar epithelial immunohistochemical expression of TGF-beta, MMP-2, 7, 9, and their tissue inhibitors (TIMP-1, 2). Results: Compared to controls, patients with UIP, NSIP and CB presented increased bronchiolar inflammation, peribronchiolar inflammation and fibrosis and decreased luminal areas. UIP patients had thicker walls due to an increase in most airway compartments. NSIP patients presented increased epithelial areas, whereas patients with CB had larger inner wall areas. All of the groups studied presented increased bronchiolar expression of MMP-7 and MMP-9, compared to the controls. Conclusion: We conclude that SAs are pathologically altered and may take part in the lung-remodeling process in idiopathic interstitial pneumonias. Copyright (C) 2009 S. Karger AG, Basel

Estrogen receptor-positive breast carcinomas in younger women are different from those of older women: A pathological and immunohistochemical study

The higher frequency of triple-negative and HER-2-positive tumors detected in younger patients has been suggested as an explanation for the more aggressive tumor types observed in this age group. However, estrogen receptor (ER)-positive tumors are the most frequent subtype of breast carcinomas identified, even in younger patients. In this retrospective study, the morphological and immunohistochemical profiles of ER-positive breast carcinomas from women 35 yrs and younger that were diagnosed between 1997 and 2007 were evaluated. From these cases, 213 were selected based on the availability of pathology reports and paraffin blocks. For comparison, 117 consecutive cases of breast carcinomas diagnosed in patients >60 yrs from 2006 were included. Paraffin-embedded tumors were stained for expression of ER, progesterone receptor (PR), human epidermal growth factor receptor 2 (HER-2). Ki-67 antigen, epidermal growth factor receptor (EGFR), cytokeratin 5/6, p53, vimentin, CD117, and p63 using tissue microarrays. ER-positive carcinomas were diagnosed in 120 (56.1%) samples of the younger patient group and in 92 (78.6%) samples of the older patient group. Of these ER-positive carcinomas, 48 (40%) from the younger patient group presented the subtype luminal A, compared with 53 (57.6%) from the older patient group (p=0.01). Tumors from the younger patient group were also associated with increased vascular involvement, co-expression of HER-2, and decreased expression of CD117. These results highlight differences in expression markers and the pathology of ER-positive tumors detected in younger women, with a notable characteristic being co-expression of HER-2. (C) 2010 Elsevier Ltd. All rights reserved.

A study of actinic cheilitis treatment by two low-morbidity CO(2) laser vaporization one-pass protocols

Therapeutic approaches to chronic actinic cheilitis focus on the removal or destruction of diseased epithelium. The CO(2) laser has become an important therapeutic alternative, achieving clinical resolution in around 90% of patients. Although many laser physical parameters have been reported, some are known for their low potential for scar induction without compromising the success of the results. The aim of this clinicohistological study was to compare the therapeutic responses to two low-morbidity protocols involving a single laser pass. A total of 40 patients with chronic multicentric and microscopically proven disease were randomly submitted to two conservative CO(2) laser protocols using a bilateral comparative model. The degree of histological atypia of the epithelium was determined in 26 patients both pre- and postoperatively for both protocols. Other histological phenomena were assessed in addition to this central analysis parameter. Clinical recurrence occurred in 12.5% of patients for each protocol, together with a significant reduction in the degree of epithelial atypia (p < 0.001), which was occasionally complete. However, no difference was found between the protocols (p > 0.05). Using these morphological parameters it was not possible to determine whether postoperative epithelial atypias in part of the sample were reactive or residual in nature. A few patients may show minor postoperative lesions. Due to their potential to achieve clinical and importantly microscopic resolution, the studied protocols may be used for mild through moderate dysplastic epithelium and clinically diffuse disease.

Stretch Injuries of Skeletal Muscles: Experimental Study in Rats` Soleus Muscle

The study aimed to verify the physiological injury behavior by stretching the soleus muscle of rats, using a noninvasive experimental model. Twenty-four rats were used and divided into three groups of eight animals: control group (A), group that performed tetanus followed by electrical stimulation and a sudden dorsiflexion of the left paw performed by a device equipped with a mechanism of muscle soleus rapid stretching (B); and a group that only received the tetanus (C). Three days later, the animals were killed, and the soleus muscle was resected and divided into three segments. Morphological changes indicative of muscle damage appeared in all three segments of group B. In a lesser degree, similar changes were also detected in muscles subjected to only tetanus. This model was effective; reproducing an injury similar to what occurs in human sports injuries.

A morphometric study on the longitudinal and lateral symmetry of the sural nerve in mature and aging female rats

Aging affects peripheral nerve function and regeneration in experimental models but few literature reports deal with animals aged more than one year. We investigated morphological and morphometric aspects of the sural nerve in aging rats. Female Wistar rats 360, 640 and 720 days old were killed, proximal and distal segments of the right and left sural nerves were prepared for light microscopy and computerized morphometry. No morphometric differences between proximal and distal segments or between right and left sides at the same levels were found in all experimental groups. No increase in fiber and axon sizes was observed from 360 to 720 days. Likewise, no difference in total myelinated fiber number was observed between groups. Myelinated fiber population distribution was bimodal, being the 720-days old animals` distribution shifted to the left, indicating a reduction of the fiber diameters. The 9 ratio distribution of the 720-days old animals` myelinated fiber was also shifted to the left, which suggests axonal atrophy. Morphological alterations due to aging were observed, mainly related to the myelin sheath, which suggests demyelination. Large fibers were more affected than the smaller ones. Axon abnormalities were not as common or as obvious as the myelin changes and Wallerian degeneration was rarely found. These alterations were observed in all experimental groups but were much less pronounced in rats 360 days old and their severity increased with aging. in conclusion, the present study indicates that the aging neuropathy present in the sural nerve of female rats is both axonal and demyelinating. (C) 2008 Elsevier B.V. All rights reserved.

Bovine Peritoneum Protection Role on Intestinal Adhesions to a Vascular Graft: A Morphological Analysis

The present study aimed to experimentally evaluate the protection role of glycerin preserved bovine peritoneum (BP) against intestinal adhesions to a vascular graft. Experiments were performed on 24 adult rabbits, randomly dived into two groups. All animals were submitted to a vascular graft over the infra-renal aorta and vena cava. Group I (12 animals) was submitted to a BP patch on the retroperitoneal opening, between the vascular prosthetic graft and the intestinal loops. Group II (12 animals) had the retroperitoneal opening sutured. After 7, 14, 28 and 60 days, 3 animals of each group were randomly killed and the retro peritoneum, with or without the BP patch, was removed for histological analysis. The histological analysis showed that the BP stimulated a moderate to intense inflammatory reaction at the beginning of the experiments and on the 60-day evaluation, the inflammatory reaction was mild, limited to the BP border with its histological structure preserved. In conclusion, the BP is a safe and cheap interposition material to be used between vascular grafts and intestinal loops, presenting a protection role against adhesions between them.

Morphological comparison of different protocols of skeletal muscle remobilization in rats after hindlimb suspension

The aim of this study was to evaluate and compare the efficacy of different remobilization protocols in different skeletal muscles considering the changes induced by hindlimb suspension of the tail. Thirty-six female Wistar rats were divided into six groups: control I, control II, suspended, suspended free, suspended trained on a declined treadmill and suspended trained on a flat treadmill. Fragments of soleus and tibialis anterior (TA) muscle were frozen and processed by different histochemical methods. The suspended soleus showed a significant increase in the proportional number of intermediate/hybrid fibers and a decrease in the number of type I fibers. Some of these changes proved to be reversible after remobilization. The three remobilization programs led to the recovery of both the proportional number of fibers and their size. The TA muscle presented a significant increase in the number and size of type I fibers and a cell size reduction of type IIB fibers, which were recovered after training on a declined treadmill and free movement. Especially regarding the soleus, the present findings indicate that, among the protocols, training on a declined treadmill was found to induce changes of a more regenerative nature, seemingly indicating a better tissue restructuring after the suspension procedure.

Intravitreal triamcinolone versus bevacizumab for treatment of refractory diabetic macular oedema (IBEME study)

Background/aims: The aim of this study was to compare the morphological and visual acuity outcomes associated with a single intravitreal injection of triamcinolone acetonide versus bevacizumab for the treatment of refractory diffuse diabetic macular oedema. Methods: Twenty-eight patients were randomly assigned to receive a single intravitreal injection of either 4 mg/0.1 ml triamcinolone acetonide or 1.5 mg/0.06 ml bevacizumab. Comprehensive ophthalmic evaluation was performed at baseline and at weeks 1, 4, 8 (+/- 1), 12 (+/- 2) and 24 (+/- 2) after treatment. Main outcome measures included central macular thickness measured with optical coherence tomography (OCT) and best corrected Early Treatment Diabetic Retinopathy Study (ETDRS) visual acuity. Results: Twenty-six patients (26 eyes) completed all study visits (two patients missed two consecutive study visits). Central macular thickness was significantly reduced in the intravitreal triamcinolone group compared with the bevacizumab group at weeks 4, 8, 12 and 24 (p<0.05). Logarithm of the minimum angle of resolution (LogMAR) best-corrected visual acuity was significantly higher at weeks 8 (0.69; similar to 20/100(+1)) and 12 (0.74; 20/100(-2)) in the intravitreal triamcinolone group compared with the bevacizumab group (weeks 8 (0.83; similar to 20/125(-1)) and 12 (0.86; 20/ 160(+2))) (p<0.05). Significant change from baseline in mean intraocular pressure (mmHg) was seen at week 4 (+2.25) only in the intravitreal triamcinolone group (p<0.0001). No patient had observed cataract progression during the study. Conclusions: One single intravitreal injection of triamcinolone may offer certain advantages over bevacizumab in the short-term management of refractory diabetic macular oedema, specifically with regard to changes in central macular thickness. The actual clinical relevance of our preliminary findings, however, remains to be determined in future larger studies.