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Results for “Morphological Characterization”

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PubMed2005

Use of intravenous immunoglobulin in toxic epidermal necrolysis and Stevens-Johnson syndrome: our current understanding.

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN, Lyell's disease, syndrome) are considered to be part of a spectrum of adverse cutaneous drug reactions with increasing severity and extent of skin detachment, ranging from SJS (less than 10% body surface area skin detachment, 1-5% mortality) to TEN (greater than 30% skin detachment, 25-35% mortality). Both SJS and TEN are characterized morphologically by ongoing apoptotic keratinocyte cell death that results in the separation of the epidermis from the dermis. Recent evidence is supportive of a role for the death receptor Fas and its ligand FasL, in the pathogenesis of keratinocyte apoptosis during TEN. This Fas-mediated keratinocyte apoptosis that causes epidermal detachment in TEN can be inhibited in vitro by antagonistic monoclonal antibodies to Fas and by intravenous immunoglobulins (IVIG) which have been shown to contain natural anti-Fas antibodies. Over the last 6 years, numerous case reports and 8 non-controlled clinical studies containing 9 or more patients have analyzed the therapeutic effect of IVIG in TEN. Taken together, although each study has its potential biases, 6 of the 8 studies point towards a benefit of IVIG used at doses greater than 2 g/kg on the mortality associated with TEN. Hopefully, these studies will serve as the basis for designing a prospective controlled trial in the near future; as such, an approach appears the only way to definitively determine the therapeutic potential of IVIG in TEN.

Clinical Trials as Topic↗

PubMed2005

Peptide-derivatized biodegradable nanoparticles able to cross the blood-brain barrier.

Injectable nanoparticulate drug carriers (Np) able to cross the blood-brain barrier (BBB) have important potential applications for the treatment of diseases that affect the central nervous system (CNS). With the aim to create a system able to address Np to the CNS, we synthesized conjugates between a biodegradable copolymer, poly(D,L-lactide-co-glycolide) (PLGA), and five short peptides, by means of an amidic linkage. These peptides, that are similar to synthetic opioid peptides, were synthesized in turn by means of Fmoc solid-phase peptide synthesis. The new five modified copolymers thus obtained turned out to be valuable starting material for the preparation of Np; these were made fluorescent, in order to allow their localization after their administration, by inclusion of a fluorescent probe. The Np thus prepared were characterized (morphology, size and z-potential) and were shown to possess the peptidic moieties on their surface, as evidenced by ESCA spectroscopy. Then, their ability to cross the BBB was assessed by the in vivo Rat Brain Perfusion Technique and, in one case, by means of a systemic administration (rat femoral vein injection). Fluorescent and confocal microscopy studies showed that while PLGA Np are unable to cross the BBB, for the first time these solid Np surface-modified with peptides were shown to be able to cross the BBB.

Animals↗

PubMed2003

The isolation and culture of microglia-like cells from the goldfish brain.

We have developed a method for isolating goldfish microglia. Cells were identified as microglia immunohistochemically with NN-2, a monoclonal antibody (MAb) raised against teleost retinal microglial cells, and by their phagocytic abilities. Morphological characterization of the cells identified round, phase-bright cells as well as flattened macrophage-like cells. Ramified cells were also seen but they were rare. Fusion of macrophage-like cells occurred in high density cultures and resulted in the formation of giant cells that disintegrated a few days later. Immunohistochemical studies demonstrated that virtually all of the cells in our cultures were NN-2+ and did not label with either antiGFAP (an astrocyte marker) or MAb 6D2 (an oligodendrocyte marker). Cells identified as microglia were intensely phagocytic and ingested latex microspheres, DiIAcLDL and goldfish myelin in vitro. In addition, we labelled microglial cells in vivo with intracranial injections of fluorescent dextran and found that microglia isolated from these animals contained the dextran and phagocytosed microspheres. We also studied the effect of myelin on microsphere uptake and compared the effect of myelin and opsonized myelin on the phagocytic activity of the cells. Our results showed a clear increase in the phagocytic activity of microglia when incubated with myelin, with an enhanced effect of opsonized myelin.

Animals↗

PubMed2005

A density-based approach for the modelling of root architecture: application to Maritime pine (Pinus pinaster Ait.) root systems.

Root morphology influences strongly plant/soil interactions. However, the complexity of root architecture is a major barrier when analysing many phenomena, e.g. anchorage, water or nutrient uptake. Therefore, we have developed a new approach for the representation and modelling of root architecture based on branching density. A general root branching density in a space of finite dimension was used and enabled us to consider various morphological properties. A root system model was then constructed which minimizes the difference between measured and simulated root systems, expressed with functions which map root density in the soil. The model was tested in 2D using data from Maritime pine Pinus pinaster Ait. structural roots as input. We showed that simulated and real root systems had similar root distributions in terms of radial distance, depth, branching angle and branching order. These results indicate that general density functions are not only a powerful basis for constructing models of architecture, but can also be used to represent such structures when considering root/soil interaction. These models are particularly useful in that they provide a local morphological characterization which is aggregated in a given unit of soil volume.

Models, Biological↗

PubMed2005

Biventricular repair in children with atrioventricular septal defects and a small right ventricle: anatomic and surgical considerations.

OBJECTIVE: We sought to characterize morphology and to evaluate a strategy of using biventricular repair in patients with a small right ventricle and an unbalanced atrioventricular septal defect. METHODS: Thirty-eight children with a small right ventricle and an atrioventricular septal defect underwent operative therapy. Thirty-two had biventricular repair, and 6 had single-ventricle palliation. A small right ventricle was defined on the basis of echocardiographic measurements expressed as the atrioventricular valve index (ie, right atrioventricular valve/left atrioventricular valve area) and as the ratio of right ventricular to left ventricular length. Validation of measurements in patients with a small right ventricle and an atrioventricular septal defect was achieved by comparison with balanced case-matched control subjects with atrioventricular septal defects. RESULTS: Children with a small right ventricle and an atrioventricular septal defect had a lower atrioventricular valve index (mean, 0.41 +/- 0.1 vs 0.52 +/- 0.1 [control], P < .0001) and lower right ventricular/left ventricular length ratio (0.78 +/- 0.1 vs 0.99 +/- 0.17 [control], P < .0001). Children with a small right ventricle undergoing single-ventricle palliation had the smallest right ventricular dimensions. There were 4 operative deaths. Three patients with a small right ventricle and an atrioventricular septal defect who underwent biventricular repair and had an atrioventricular valve index of less than 0.50 required early reoperation for right ventricular inadequacy. A restrictive atrial fenestration was created in 11 infants. Survival at 10 years was 87% for patients undergoing biventricular repair versus 100% for control subjects (P = .042). CONCLUSIONS: Extending the use of biventricular repair in properly selected patients with a small right ventricle and an atrioventricular septal defect is feasible. An atrial fenestration improves the physiologic tolerance to repair in selected patients. The use of biventricular repair in children with atrioventricular valve indexes of less than 0.50 requires caution.

Cardiac Surgical Procedures↗

PubMed2006

Angiotensin II induces histomorphologic features of unstable plaque in a murine model of accelerated atherosclerosis.

BACKGROUND: We explored the role of angiotensin II in determining the histomorphometric features of plaque stability in apolipoprotein E-deficient mice submitted to ligation of the carotid artery. METHODS: Six-month-old apolipoprotein E-deficient mice underwent ligation of the common left carotid artery and were immediately assigned to receive either angiotensin II (1.4 mg . kg(-1) . d(-1) subcutaneously) or vehicle (phosphate-buffered saline; control) via a subcutaneous osmotic minipump for 4 weeks. RESULTS: Ligated arteries from control animals developed intimal lesions composed of macrophage foam cell plaques, which accumulated adjacent to the internal elastic lamina and were surrounded by a fibromuscular layer. Angiotensin II-treated mice had a greater intimal area (threefold), which was accompanied by a fivefold increase in the foam cell area. Lesions from angiotensin II-treated mice also displayed complex morphology characterized by intralesional neovasculature and hemorrhage. The content of active matrix metalloproteinase 2, mainly colocalized with macrophage foam cells, and the production of the inflammatory mediators monocyte chemoattractant protein 1 and vascular cell adhesion molecule 1 were also increased by angiotensin II treatment. Although angiotensin II induced vessel expansion and lumen loss to a similar extent, only vessel enlargement correlated with intimal area. CONCLUSIONS: Taken together, this study's results support a role of angiotensin II in plaque vulnerability by promoting intraplaque neovascularization/hemorrhage, inflammation, and expansive remodeling.

Angiotensin II↗

PubMed2004

Interaction of pathogenic bacteria with rabbit appendix M cells: bacterial motility is a key feature in vivo.

Rabbit appendix consists mainly of lymphoid follicles (LF) covered by M cells, the specialized antigen-sampling cells of the mucosal immune system, and surrounded by glandular epithelium. Until now, these M cells have been characterized morphologically and histologically by using cellular markers. Here, the adhesion and transport of pathogenic bacteria were investigated to assess the function of M cells of the appendix. We used the enteroinvasive motile Salmonella typhimurium and the rabbit enteropathogenic non-motile Escherichia coli RDEC-1, which are known to target specifically rabbit M cells of Peyer's patches (PPs). We found that S. typhimurium efficiently attached and was transported through appendix M cells in vivo. In contrast to S. typhimurium, RDEC-1 targeted M cells only ex vivo, when bacteria were allowed to have direct contact with the surface of the follicle. The difference in interaction of the two bacteria with appendix M cells led us to investigate whether this could be correlated with the lack of motility of RDEC-1. We used an aflagellate mutant of S. typhimurium and found that it had the same infection phenotype as RDEC-1. Gene complementation restored the efficiency of infection to that of S. typhimurium wild-type strain. In conclusion, we show that M cells of the appendix display features of the canonical M cells of PP, since they efficiently sample luminal pathogenic bacteria. However, due to the morphology of the appendix, motile bacteria appear to be more potent in their interactions with appendix M cells.

Animals↗

PubMed2005

Organic solvent-induced cell death in rat cerebellar granule cells: structure dependence of c10 hydrocarbons and relationship to reactive oxygen species formation.

Previously, increased formation of reactive oxygen species (ROS) has been demonstrated in cultured rat cerebellar granule cells (CGCs) exposed to t-butylcyclohexane, n-decane, and n-butylbenzene (Dreiem et al. Relationship between lipophilicity of C6-10 hydrocarbon solvents and their ROS-inducing potency in rat cerebellar granule cells. Neurotoxicology 2002;23:701-9). In the present paper, we have studied the effects of these hydrocarbons on the viability of CGCs. Cell death was assessed by measurement of lactate dehydrogenase (LDH) release and trypan blue staining. t-butylcyclohexane and n-butylbenzene induced cell death in rat CGCs in a time-dependent and concentration-dependent manner. In contrast, n-decane did not cause release of LDH from rat CGCs even at 1mM. Morphological studies revealed apoptotic morphology characterized by cell shrinkage and chromatin condensation after exposure to low concentrations of t-butylcyclohexane and n-butylbenzene. However, there was no internucleosomal DNA fragmentation and no protection by the pan-caspase inhibitor Boc-D-FMK or the protein synthesis inhibitor cycloheximide. This indicates that cell death after t-butylcyclohexane and n-butylbenzene exposure is an intermediate between classical apoptosis and necrosis. Treatment with the antioxidant alpha-tocopherol ameliorated hydrocarbon-induced cell death, indicating involvement of reactive oxygen species in the mechanism of hydrocarbon toxicity. The significance of ROS formation in relation to cell death is discussed.

Animals↗

PubMed2004

Why voxel-based morphometric analysis should be used with great caution when characterizing group differences.

A variety of voxel-based morphometric analysis methods have been adopted by the neuroimaging community in the recent years. In this commentary we describe why voxel-based statistics, which are commonly used to construct statistical parametric maps, are very limited in characterizing morphological differences between groups, and why the effectiveness of voxel-based statistics is significantly biased toward group differences that are highly localized in space and of linear nature, whereas it is significantly reduced in cases with group differences of similar or even higher magnitude, when these differences are spatially complex and subtle. The complex and often subtle and nonlinear ways in which various factors, such as age, sex, genotype and disease, can affect brain morphology, suggest that alternative, unbiased methods based on statistical learning theory might be able to better quantify brain changes that are due to a variety of factors, especially when relationships between brain networks, rather than individual structures, and disease are examined.

Bias↗

PubMed2005

Phosphorylation of Neurogenin2 specifies the migration properties and the dendritic morphology of pyramidal neurons in the neocortex.

The molecular mechanisms specifying the dendritic morphology of different neuronal subtypes are poorly understood. Here we demonstrate that the bHLH transcription factor Neurogenin2 (Ngn2) is both necessary and sufficient for specifying the dendritic morphology of pyramidal neurons in vivo by specifying the polarity of its leading process during the initiation of radial migration. The ability of Ngn2 to promote a polarized leading process outgrowth requires the phosphorylation of a single tyrosine residue at position 241, an event that is neither involved in Ngn2 direct transactivation properties nor its proneural function. Interestingly, the migration defect observed in the Ngn2 knockout mouse and in progenitors expressing the Ngn2(Y241F) mutation can be rescued by inhibiting the activity of the small-GTPase RhoA in cortical progenitors. Our results demonstrate that Ngn2 coordinates the acquisition of the radial migration properties and the unipolar dendritic morphology characterizing pyramidal neurons through molecular mechanisms distinct from those mediating its proneural activity.

Age Factors↗

PubMed2006

Pharmacological and histopathological characterization of a hyperalgesia model induced by freeze lesion.

Induction of a freeze lesion in human skin is an experimental model of hyperalgesia that allows assessing the antihyperalgesic effects of traditional non-steroidal anti-inflammatory drugs (NSAIDs). We have investigated whether this model is also sensitive to selective cyclooxygenase (COX)-2 inhibitors and have characterized morphological substrates of the generated hyperalgesia in the skin. In eight healthy subjects, a freeze lesion was induced and mechanical pain thresholds (MPT) were tested for 5h following administration of the non-selective COX inhibitor diclofenac (75mg), the COX-2-selective inhibitor parecoxib (40mg) or placebo in a randomized, double-blind cross-over study. In five additional healthy subjects, biopsies were taken from normal skin and the area of freezing injury. Induction of the freeze lesion resulted in hyperalgesia expressed by a decrease of MPT after 24h. Diclofenac and parecoxib, but not placebo, statistically significantly elevated MPT. Histochemical and Western blot analyses of skin biopsies revealed a strong upregulation of COX-2, a slight decrease of COX-1 and activation of nuclear factor kappa B (NF-kappaB) in the area of the freezing injury. These findings indicate that the freeze lesion model is sensitive to NSAIDs including selective COX-2 inhibitors, and that NF-kappaB-dependent COX-2 upregulation contributes to the hyperalgesia in this model.

Adult↗

PubMed2003

Neuropeptides in perisympathetic organs of Manduca sexta: specific composition and changes during the development.

We used a combination of matrix-assisted laser desorption-ionization time-of-flight mass spectrometry and immunocytochemistry to investigate the peptides from abdominal perisympathetic organs of Manduca sexta. Altogether three mass peaks, detected in mass spectra from single abdominal perisympathetic organs were identical with already known neuropeptides, namely CAP(2b), CCAP, and Manduca-allatotropin. Only CAP(2b) was found throughout the postembryonic development. In larvae, perisympathetic organs of the abdominal ganglia 1 and 7 do not accumulate neuropeptides. During the metamorphosis, the number of putative hormones stored in the abdominal perisympathetic organs, increases dramatically. Not a single substance, however, obtained in mass spectra of larval perisympathetic organs disappeared in the respective adult neurohemal organs. Peptides from abdominal perisympathetic organs are different from those of thoracic perisympathetic organs and the retrocerebral complex. Manduca-FLRFa-2 and -3 are enriched in thoracic perisympathetic organs; FLRFa-1, corazonin and adipokinetic hormone are abundant peptides of the retrocerebral complex. The majority of ion signals, however, represent unknown substances. An antiserum which recognized CAP(2b) allowed the morphological characterization of a median neurosecretory system in the abdominal ventral nerve cord of M. sexta, which resembles that of cockroach embryos. Double stainings confirmed that crustacean cardioactive peptide (CCAP) becomes colocalized with CAP(2b) in median neurosecretory cells during the last larval instar. This colocalization continues in adult insects.

Abdomen↗

PubMed2004

Programmed cell death induces male sterility in Actinidia deliciosa female flowers.

The importance of programmed cell death (PCD) during the life cycle of plants is well established, although the underlying molecular mechanisms are still poorly defined. An emerging system for the study of PCD during development in plants is that of sex organ abortion. In this work we investigate the degeneration of microspores in the anthers of Actinidia deliciosa female flowers. The kiwifruit, A. deliciosa, is a dioecious species native to China. Pollen development in female flowers is equivalent to pollen development in the male flowers, until the microspores are released from the tetrads. At this time the first differences appear, and include the condensation and shrinkage of the cytoplasm, blebbing of the plasma membrane and of the nuclear envelope, and condensation of chromatin. However, at the time these events are occurring, all other cellular organelles, including mitochondria, have their structures well preserved. Fragmentation of DNA was detected in situ by the TUNEL procedure, which involves the end labeling of the DNA fragments by terminal deoxynucleotidyl transferase with UTP conjugated to a detectable marker. This assay confirmed the morphological characterization of PCD in this system.

Actinidia↗

PubMed2006

Impact strength and fracture morphology of denture acrylic resins.

STATEMENT OF PROBLEM: Microwave-polymerization cycles may affect the impact strength and fracture morphology of denture base acrylic resin, and the microstructural effects of these processes have not been fully determined. PURPOSE: This study evaluated the impact strength and fracture morphology of denture base acrylic resins processed by microwave energy and hot water bath. MATERIAL AND METHODS: Twenty specimens measuring 65 x 10 x 2.5 mm were fabricated from each of 4 acrylic resins processed according to the manufacturers' recommendations: Lucitone 550 (control; 9 hours at 74 degrees C); Onda Cryl (3 minutes at 360 W + 4 minutes pause + 3 minutes at 810 W); Acron MC (3 minutes at 500 W); and Vipi Wave (20 minutes at 180 W + 5 minutes at 540 W). The impact strength was evaluated in an impact testing machine using the Charpy method with a load (impact action) of 3.95 J. Mean values of impact strength were compared by Tukey honestly significant difference test (alpha = .05). Fractures were classified as brittle or intermediate. Fractographic analysis was performed for all fragments by angle analyses of crack propagation, and the microstructural morphology characterization was accomplished with scanning electron microscopy (SEM). Data from the fractography analysis were submitted to the Kruskal-Wallis test for angles and radius (alpha = .05). RESULTS: Significant differences (P < .001) were found in the impact strength for Vipi Wave and Acron MC acrylic resins, which demonstrated the lowest values (0.19 +/- 0.04 and 0.21 +/- 0.02, respectively). Most fractures were classified as brittle (Lucitone 55%; Onda Cryl 75%; Acron MC 90%; Vipi Wave 65%). Fractographic angle analysis of brittle fractures showed no differences among acrylic resins studied; however, angle values of intermediate fractures for Onda Cryl were lower in comparison with those from Lucitone 550 and Vipi Wave (P = .03). The SEM observations revealed that brittle fractures showed defined and organized crystallographic planes, whereas the intermediate fractures had a disorganized appearance. CONCLUSION: Within the limitations of this study, it was observed that impact strength in microwave-polymerized acrylic resins varies according to the period of irradiation. Acrylic resins exhibited a high number of brittle fractures, irrespective of the processing technique.

Acrylic Resins↗

PubMed2006

Toxic epidermal necrolysis and intravenous immunoglobulin: a review.

Toxic epidermal necrolysis (TEN, Lyell's syndrome) is a rare, life-threatening hypersensitivity reaction to certain medications, such as sulfonamides, antibiotics, non-steroidal anti-inflammatory drugs, and anti-convulsants. The incidence of TEN is 0.4-1.2 cases per million per year in the general population and 1 case per thousand per year in the HIV+ population. It is characterized morphologically by ongoing apoptotic keratinocyte cell death that results in the separation of the epidermis from the dermis. TEN carries a mortality of upwards of 40%, with the vast majority of patients succumbing to sepsis or multiorgan failure. Recent insights into the pathogenesis of TEN revealed that keratinocytes undergo Fas-FasL mediated apoptosis. No specific treatment for TEN exists to date. Attempts have been made to decrease mortality in TEN patients through supportive care and adjuvant therapies. Since 1988, intravenous immunoglobulin (IVIG) has been shown to interfere with the interaction of Fas and FasL, and can be used as a treatment for TEN. This paper reviews the recent studies in the literature that have looked at the use of IVIG to treat TEN.

Humans↗

PubMed2005

Venom production in long-term primary culture of secretory cells of the Bothrops jararaca venom gland.

There is an increasing interest of obtaining venom by other ways than from extracting it from snakes captured in the wild. A readily available source of this venom will be useful for all pharmacological and biotechnological studies, as well as providing an improved avenue for treatments of snakebites. Here, we show that secretory cells of venom gland can be a good in vitro apparatus to produce venom. We have maintained and morphologically characterized the secretory cells of the Bothrops jararaca venom gland cultured up to 21 days. The isolated cells assemble into acini that growth in size up to 21st day, instead of adhering to the substrate. Bothropasin, a venom metalloprotease, was localized in secretory vesicles by immunoelectron microscopy and venom was also detected in culture medium in a concentration as high as 63 microg/ml. These data show that the acini formed in culture are functionally viable; they can produce and secrete venom.

Animals↗

PubMed2004

Prognostic significance of morphological subtypes in canine malignant lymphomas during chemotherapy.

The aim of this study was to determine the response of different morphological subtypes of canine lymphoma to a standardized therapeutic protocol. Diagnosis of lymphoma was based on cytohistological analysis and immunophenotyping with antibodies against CD3 and CD79a of an enlarged lymph node or an extranodal mass. Fifty-seven cases were classified according to the updated Kiel classification adapted to the canine species, into 24 B-cell lymphomas (20 centroblastic polymorphic and four Burkitt-type subtypes), and 33 T-cell lymphomas (10 pleomorphic mixed, 10 lymphoblastic, eight unclassifiable high grade plasmacytoid, and five small clear-cell subtypes). All dogs were clinically staged at diagnosis. The protocol used l-asparaginase, vincristine, cyclophosphamide, doxorubicin, and prednisone. First remission duration and overall survival time were evaluated. Although the T-cell phenotype was associated, on the whole, with a poor prognosis, as previously reported in veterinary and human medicine, the study showed significant prognostic differences between the B- and the T-cell subtypes of canine lymphoma and suggests that clinico-morphological characterization of the disease is justified in dogs, as in humans.

Animals↗

PubMed1997

Phase behavior of fluorocarbon di-O-alkyl-glycerophosphocholines and glycerophosphoethanolamines and long-term shelf stability of fluorinated liposomes.

This paper is devoted to the morphological characterization, by freeze-fracture electron microscopy, and to the thermotropic phase behavior, by differential scanning calorimetry and X-ray diffraction of the aqueous dispersions of various fluorocarbon/fluorocarbon or mixed fluorocarbon/hydrocarbon 1,2- or 1,3-di-O-alkyl-glycerophosphocholines (PC) and 1,2-di-O-alkyl-glycerophosphoethanolamines (PE). The fluorinated PCs form classical lamellar phases and liposomes while an interdigitated lamellar phase has been evidenced for a hydrocarbon 1,3-analog. The fluorinated PEs display a lamellar to hexagonal phase transition which occurs almost simultaneously with the gel-to-fluid lamellar phase transition. The impact of each of the structural features [ether vs ester chemical junction connecting the hydrophobic chains on glycerol, their position (1,2- vs 1,3 isomers), number and length of the perfluoroalkylated chains, length of the fluorinated tail and hydrocarbon spacer, PC vs PE polar head] of the fluorinated phospholipids on the phase transition thermodynamic parameters (Tc, delta H, delta S) is discussed. Most of the liposomes formed from the fluorinated ether-PCs display a remarkable long-term shelf stability: they can be thermally sterilized and stored at room temperature for several months without any significant modification of their size and size distribution.

Calorimetry, Differential Scanning↗