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Results for “computational morphology”

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At least 685 records · Page 38Linked to original sources

PubMed2006

Differential, time-dependent effects of perivenous application of fibrin glue on medial thickening in porcine saphenous vein grafts.

OBJECTIVE: Neointimal and medial thickening play a critical role in late vein graft failure following CABG. Previous ex vivo experiment suggested that perivenous application of fibrin glue may reduce the damage in the circular smooth muscle cell layer of the media of the vein graft shortly after exposing to arterial pressure. However, the in vivo as well as the longer term impact of this intervention remain unknown. METHODS: Bilateral saphenous vein-carotid artery interposition grafting was performed in eight large white pigs (35-45 kg). In each pig, one of the grafts was randomly selected to receive perivenous fibrin glue support while the contralateral graft served as control. At 1 and 4 months following surgery (n=4 pigs in each group), all 16 patent vein grafts were removed and pressure-fixed. Multiple histological sections from each graft were prepared. Proliferating cell nuclear antigen (PCNA) was detected by immunocytochemistry. Vein graft morphology was assessed using computer-aided planimetry. RESULTS: Although perivenous application of fibrin glue had little effects either on medial thickness 1 month after implantation or on PCNA index, it significantly increased medial thickness (control: 0.37+/-0.02 mm; treated: 0.55+/-0.02 mm, p<0.001) and total wall thickness (control: 0.75+/-0.04 mm; treated: 0.92+/-0.04 mm, p=0.008) at 4 months (mean+/-SEM; n=4 in each group). CONCLUSIONS: Our data indicated that perivenous application of fibrin glue enhances graft thickening and as such does not constitute a strategy for preventing late vein graft failure after CABG.

Anastomosis, Surgical↗

PubMed2005

Theoretical aspects of canine cryopreserved semen evaluation.

Evaluation of canine cryopreserved semen has the ultimate goal of determining if an individual frozen ejaculate will have acceptable fertility. This is difficult in that there is no accepted normal fertility for the dog. The fertility of the female also plays a crucial role in estimating the fertility of the male. Poor female fertility can make a fertile male appear less fertile. Variability of animals, breeding technique, breeding timing, and number of cells inseminated make comparisons in canine fertility difficult to truly measure. Many more animals are needed to provide meaningful statistical results than are usually used. Several tests, including motility in bright field and phase contrast microscopy, computer analysis of motility, sperm morphology, sperm membrane integrity, capacitation and sperm function tests have been investigated to predict fertility, however few of these tests have actually been correlated with fertility. More work is needed to create one or more tests that accurately predict fertility of cryopreserved canine semen.

Animals↗

PubMed1999

[Mycotic aneurysm after kidney transplantation].

PURPOSE: The study aim was to report six cases of mycotic aneurysms in renal transplant patients and to review the literature on this subject. PATIENTS AND METHODS: Six patients, aged from 13 to 59 years, who had undergone renal transplantation 4 months to 16 years earlier, developed a mycotic aneurysm after bacteremia. The diagnosis was based on morphological investigations (echotomography, arteriography, spiral computed tomography) and bacteriological studies (blood culture, culture of the aneurysmal wall and content). The aneurysm was located in five cases at the anastomosis of the renal artery with the iliac axis, and in one case on the popliteal artery and tibioperoneal trunk. All patients were treated surgically: five reconstructions were performed using two arterial iliac prostheses, three hypogastric artery autografts and one saphenous vein graft (combined with an iliac prosthesis); one repair was impossible because of profuse local suppuration, and endoaneurysmorraphy with multiple ligatures of the popliteal vessels was performed. Postoperative radiological control was performed in all cases of arterial repair. All patients received antibiotic therapy during three to six months after the operation. RESULTS: No postoperative mortality occurred. All kidney transplants were salvaged. Anatomical results of arterial reconstructions were satisfactory in all cases and remained so during the follow-up. CONCLUSIONS: Mycotic aneurysms after renal transplantation are rare since only six observations with a kidney transplant in place have been published in the literature with a single long-lasting kidney salvage. Surgical treatment is mandatory to prevent rupture. Survival of patients occurred exclusively in operated cases.

Adolescent↗

PubMed2005

Hemosuccus pancreaticus: a rare cause of gastrointestinal bleeding.

AIM: The purpose of this study was to analyze the diagnostic and therapeutic features of hemosuccus pancreaticus. METHODS: We conducted a retrospective study of nine patients (eight men and one woman, mean age 60 yrs) admitted to surgery or gastroenterology units for hemossucus pancreaticus between 1981 and 2003. The following were studied: symptoms, contribution of established morphologic exams (upper digestive endoscopy, computed tomography (CT) and selective digestive angiography) and treatment. RESULTS: Hemosuccus pancreaticus occurred in chronic alcoholic pancreatitis (N=8) and chronic familial pancreatitis (N=1). Seven patients (77.8%) presented overt digestive bleeding (one melena, two hematochezia, two melena with hematochezia, one hematemesis, one hemorrhagic shock). The inaugural sign was anemia in one patient and epigastric pain in another. An upper digestive endoscopy, performed in eight patients (88.9%), revealed fresh red blood in the first or second duodenum in three and hemossucus pancreaticus in three others. Arteriography was performed in eight patients (88.9%) and CT angiography in one. Surgery was performed in 5 patients (55.6%), after embolization in one. Embolization was effective in 3 patients. Therapeutic abstention proved successful in one patient. There were no deaths. CONCLUSIONS: Hemosuccus pancreaticus is a rare cause of digestive bleeding. Upper digestive endoscopy and selective digestive angiography during active bleeding can provide the diagnosis. Endovascular treatment can control an unstable hemodynamic situation before elective surgery to prevent recurrence, which can be more severe than the first event.

Aneurysm↗

PubMed2000

Intimal growth and neovascularization in human stenotic vein grafts.

BACKGROUND: Myointimal thickening and microvessel ingrowth are commonly observed in vein graft stenosis, which complicates a third of infrainguinal bypass procedures. But a direct correlation between these two features has not been established. Our purpose was to analyze the relationship between neovascularity and intimal thickness in human vein grafts. STUDY DESIGN: Twenty-two explant stenotic vein grafts (STVG), 8 nonstenotic arterialized vein grafts (AVG), and 20 age-matched control greater saphenous veins (CGSV) were analyzed histologically and compared morphologically by light microscopy. Digitized computer image analysis was used to measure intimal thickness and quantitate microvessel ingrowth. Immunolocalization of endothelial cells around the lumen and in microvessels was determined using antibodies to factor VIII and to endothelial nitric oxide synthase (eNOS), respectively. RESULTS: Focal areas of endothelial disruption and thrombus deposition were present in 23% (5 of 22) of stenotic vein grafts. The neointima of STVG grafts was two- and fourfold thicker than that of AVG and CGSV, respectively (p < 0.0001). Microvessels were most frequently observed in the adventitia and media of STVG and increased in number with increasing intimal thickness (p < 0.001 by ANOVA). CONCLUSIONS: A fourfold increased neointimal thickness in critically stenotic vein grafts is associated with increased medial and adventitial neovascularization. Remodeling alone with doubling of the intimal thickness in nonstenotic arterialized vein grafts does not appear to be associated with enhancement of the graft microvasculature. More specific observations using an experimental model may allow us to further define the role of angiogenesis in vein graft stenosis and to determine the therapeutic implications of such observations.

Aged↗

PubMed2000

Harmonic analysis of mandibular form and symmetry with computerized tomographic views.

OBJECTIVE: To quantitatively describe the isotropic (ie, orientation independent) morphologic characteristics of a standardized computed tomographic image of the mandible with the use of the elliptic Fourier series. STUDY DESIGN: Spiral CT scans parallel to the mandibular plane and enclosing both mental foramina were obtained in 17 adults (9 edentulous women, mean age, 75 years; 4 edentulous men, mean age, 68 years; and 4 dentate men, mean age, 30 years). The mandibular outline was traced, digitized, and mathematically reconstructed with the elliptic Fourier series. Mandibular area, shape, and individual symmetry were quantified. RESULTS: Mandibular area and symmetry were larger in men than in women (P <.05). In men, no effect of edentulousness was observed in either area or symmetry. Mandibular shape seemed to be influenced neither by sex nor by the presence of teeth. CONCLUSION: Mandibular size and symmetry in the analyzed computed tomographic scan (which included only the mandibular basal bone) seemed to be sex related but independent of the dental status. Mandibular shape did not seem to be modified by sex or edentulousness. Different findings may be obtained in the analysis of a section of the alveolar bone.

Adult↗

PubMed2000

Intraductal papillary mucinous tumors of the pancreas: pancreatic resections guided by preoperative morphological assessment and intraoperative frozen section examination.

BACKGROUND: We undertook this study to assess the results of a policy of limited pancreatic resections for intraductal papillary-mucinous tumors (IPMT), guided by a standardized preoperative morphological assessment and the frozen section histologic examination of pancreatic resection margins. METHODS: From 1991 to 1998, there were 41 patients who underwent resection of IPMT in our center after standardized morphological preoperative assessment, including abdominal computed tomography scans, endoscopic retrograde cholangiopancreatography, and endoscopic ultrasonography. All patients but one underwent a partial pancreatic resection. RESULTS: Preoperative assessment had an 89% diagnostic accuracy for IPMT. It detected malignant transformation with a 67% sensitivity and a 95% specificity, but failed to correctly assess ductal extension of the disease in 17 cases (41%). The diagnostic accuracy of frozen section histologic examination of the pancreatic resection margin was 92%. There was no recurrence in case of in situ carcinoma when epithelial lesions were completely resected (8 cases) nor in lower grades of dysplasia (23 cases). Conversely, recurrence was constant in invasive carcinoma (10 cases) regardless of the status of the pancreatic margin. CONCLUSIONS: Frozen section histologic examination of the pancreatic resection margin is useful and reliable to ensure a complete resection of IPMT by a partial resection that prevents recurrence of noninvasive lesions.

Adenocarcinoma, Mucinous↗

PubMed1999

Semi-automated tabulation of the 3D topology and morphology of branching networks using CT: application to the airway tree.

Detailed information on biological branching networks (optical nerves, airways or blood vessels) is often required to improve the analysis of 3D medical imaging data. A semi-automated algorithm has been developed to obtain the full 3D topology and dimensions (direction cosine, length, diameter, branching and gravity angles) of branching networks using their CT images. It has been tested using CT images of a simple Perspex branching network and applied to the CT images of a human cast of the airway tree. The morphology and topology of the computer derived network were compared with the manually measured dimensions. Good agreement was found. The airways dimensions also compared well with previous values quoted in literature. This algorithm can provide complete data set analysis much more quickly than manual measurements. Its use is limited by the CT resolution which means that very small branches are not visible. New data are presented on the branching angles of the airway tree.

Algorithms↗

PubMed1996

Respiratory disease as a result of talc inhalation.

Three cases of respiratory disease in workers with occupational exposure to talc containing asbestos fibers are reported. Standard chest roentgenographs, high-resolution computed tomography, respiratory function tests, morphologic study of bronchoalveolar lavage fluid (BAL), light microscopic examination, and mineralogical analysis by transmission electron microscopy (TEM) of BAL was performed. All subjects showed bilateral pleural plaques, and in two subjects the study of BAL revealed lymphocytic alveolitis with an increased T4/T8 ratio. Mineralogical analysis of BAL detected asbestos-fiber concentrations of 510, 2039, and 3392 fibers/mL and many asbestos bodies. In one patient, mineralogical analysis of lung tissue was also performed; a concentration of 3,659,000 fibers/g dry tissue was found. Simultaneously, we performed a mineralogical study of 12 commercial talc samples, including those used by the patients during the last phase of their working lives. TEM revealed asbestos fibers in five samples. Two subjects used two of these talc powders. The study presented here confirms the need to perform all relevant clinical tests together with the study of BAL and mineralogical analysis of the materials to which the patients are or were exposed to determine occupational exposure to fibers, including those associated with talc, which are often misidentified.

Air Pollutants, Occupational↗

PubMed2004

Viscoelastic properties of dynamically asymmetric binary fluids under shear flow.

We study theoretically the viscoelastic properties of sheared binary fluids that have strong dynamical asymmetry between the two components. The dynamical asymmetry arises due to asymmetry between the viscoelastic stresses, particularly the bulk stress. Our calculations are based on the two-fluid model that incorporates the asymmetric stress distribution. We simulate the phase separation process under an externally imposed shear and compare the asymmetric case with the usual phase separation under shear flow without viscoelastic effects. We also simulate the behavior of phase-separated stable morphologies under applied shear and compute the stress relaxation.

Journal Article↗

PubMed1996

Are the characteristics of spermatozoa in the insemination medium useful for predicting in-vitro fertilization results?

To determine whether the characteristics of Percoll-selected spermatozoa are more predictive of in-vitro fertilization (IVF) results than are those of native semen, 118 semen samples from patients undergoing an IVF attempt were studied. Motility, using computer-assisted sperm analysis, and morphology were recorded before and after sperm selection on a Percoll gradient. Percoll selection increased the percentage of morphologically normal spermatozoa (58.2 +/- 19.9% versus 47.9 +/- 17.9%; p < 0.0001). This increase concerned almost all abnormalities and especially abnormalities of the midpiece (cytoplasmic droplets and bent tails). However, morphology of spermatozoa in the Percoll fraction had the same predictive value for IVF as did that for whole semen. Concerning motility, all parameters, except linearity, were improved by Percoll preparation, and their predictive value for IVF results was significantly higher in the Percoll fraction than in native semen. Therefore, it is concluded that, even if sperm characteristics are improved dramatically after Percoll selection, only motility analysis then gave more practical information than did analysis of sperm characteristics in native semen. This suggests that impairment of spermiogenesis, which presumably induces sperm abnormalities, is more important than are the actual characteristics of the spermatozoa.

Female↗

PubMed1998

Effects of clinical stage and immunological status on semen analysis results in human immunodeficiency virus type 1-seropositive men.

Complete semen analyses including computer-assisted sperm motility and morphology assessments were performed to determine if semen and sperm differed between HIV-seropositive men and fertile controls, or differed with symptoms, or CD4+ peripheral cell count categories. Previous studies included small numbers of men and presented conflicting conclusions. Two hundred and fifty non-vasectomized HIV-seropositive men and 38 fertile controls each provided one semen sample. Non-parameteric statistics were used to analyse both continuous and nominal data. Fertile men had significantly greater semen volume, sperm concentration, percent motility, percent rapid and linear motility and total strictly normal spermatozoa than HIV seropositive men. Neither total number nor subtypes of leukocytes in semen differed between the two groups. Among the HIV seropositive men, significant differences in semen analyses were found between CD4+ cell count, clinical, and AIDS categories. Lower CD4+ cell counts (< 200 mm-3) were associated with significantly lower percent motility, percent normal sperm morphology by strict criteria, significantly more spermatids in semen, and higher percentages of teratozoospermia, oligoasthenoteratozoospermia and leukocytospermia. Healthier men, based on clinical categories, had significantly more normal shaped spermatozoa and fewer had azoospermia, oligoasthenoteratozoospermia or leukocytospermia. Many HIV-seropositive men have normal semen analyses, but as the disease progresses more defects are found, particularly in strict criteria sperm morphology.

Acquired Immunodeficiency Syndrome↗

PubMed2006

Influence of short-term confinement and exercise on tibia development in growing pigs.

The influence of short-term confinement and moderate exercise on tibia development was investigated in growing pigs (36-41 kg, 10 weeks at the beginning of the study). Animals were kept for 2 weeks either in individual crates of 0.8 m(2) ('confinement', n = 4) or kept in groups of four animals in large crates of 5.6 m(2) without ('control') or with additional exercise (30 min walking at 5 days/week; 'exercise'). Bone density and morphological parameters were evaluated by computer tomography (CT). Periosteal apposition and longitudinal growth were determined after polychrome sequential labelling in weekly intervals. Cortical areas of the cross sections at the mid-shaft and at 75% of the length of the bone measured distal to the carpus by CT were significantly correlated to each other (r = 0.70) and revealed a significant reduction in confined animals. This difference was explained by lower periosteal apposition rates in these animals compared with exercised and group-housed pigs. Similarly longitudinal growth and the formation and calcification of spongiosa of the tibiae were inhibited by confinement. Thus, 2 weeks of confinement led to significant differences in bone growth and metabolism in young growing piglets when compared with animals with moderate activity.

Animals↗

PubMed1990

Structure of the reovirus cell-attachment protein: a model for the domain organization of sigma 1.

This report describes a model for the structure of the reovirus cell-attachment protein sigma 1. S1 gene nucleotide sequences were determined for prototype strains of the three serotypes of mammalian reoviruses. Deduced amino acid sequences of the S1-encoded sigma 1 proteins were then compared in order to identify conserved features of these sequences. Discrete regions in the amino-terminal two-thirds of sigma 1 sequence share characteristics with the fibrous domains of other cellular and viral proteins. Most of the amino-terminal one-third of sigma 1 sequence is predicted to form an alpha-helical coiled coil like that of myosin. The middle one-third of sigma 1 sequence appears more heterogeneous; it is predicted to form a large region of beta-sheet that is followed by a region which contains two short alpha-helical coiled coils separated by a smaller region of beta-sheet. The two beta-sheet regions are each proposed to form a cross-beta sandwich like that suggested for the rod domain of the adenovirus fiber protein (N. M. Green, N. G. Wrigley, W. C. Russell, S. R. Martin, and A. D. McLachlan, EMBO J. 2:1357-1365, 1983). The remaining carboxy-terminal one-third of sigma 1 sequence is predicted to form a structurally complex globular domain. A model is suggested in which the discrete regions of sigma 1 sequence are ascribed to morphologic regions seen in computer-processed electron micrographic images of the protein (R. D. B. Fraser, D. B. Furlong, B. L. Trus, M. L. Nibert, B. N. Fields, and A. C. Steven, J. Virol. 64:2990-3000, 1990.

Amino Acid Sequence↗

PubMed1986

Morphometric data to FIGO stage and histological type and grade for prognosis of ovarian tumours.

The prognostic value of using histological typing, grading, and morphology, in addition to clinical staging, was assessed in 98 cases of invasive ovarian cancer of the common epithelial types (serous, mucinous, and endometrial). All of these cases had at least five years of follow up. When regression analysis was used, the International Federation of Gynaecology and Obstetrics' (FIGO) staging system was the best indicator for prognosis. Analysis of a combination of morphometric features was the second best indicator, being especially useful for the those patients with stage I disease. Variables that indicated a relatively poor prognostic outcome were mitotic index above 30; volume percentage epithelium above 65%; shortest nuclear axis above a mean of 1 X 1 micrometers. Histological typing of ovarian tumours was of limited value; mucinous tumours have a somewhat better prognosis than serous tumours, but the prognostic value of typing alone was found to be limited. Qualitative histological grading was useful, but the prognostic value of morphometric grading was better. Measurement of morphological features with an interactive computer program is simple and can be done by a pathologist or a technician: in future it is likely that such automated systems of measurement will improve the objectivity of tissue analysis.

Cell Nucleus↗

PubMed1990

Pulmonary masses: contrast enhancement.

Radiographic studies to discriminate benign from malignant pulmonary masses have previously focused on the morphologic and, more recently, the computed tomographic (CT) attenuation characteristics of the lung mass. Experience with the use of an intravenously administered iodinated contrast medium in examining the enhancement properties of lung masses was reviewed. Distinctive differences in the vascularity, pathophysiologic features, and pharmacodynamics of malignant versus benign pulmonary masses were identified. Forty-five patients with peripheral pulmonary masses were examined. Enhancement was evaluated by means of optical density values measured on trispiral tomograms of the lung masses before and after bolus injection of contrast medium. Results suggest that contrast enhancement of pulmonary masses can be measured on sectional images and that this may become a feasible diagnostic method in the detection of lung cancer. CT offers a simplified technique that is now being explored by the authors.

Contrast Media↗

PubMed2006

Form and function of ON-OFF amacrine cells in the amphibian retina.

ON-OFF amacrine cells were studied with whole cell recording techniques and intracellular staining methods using intact retina-eyecup preparations of the tiger salamander (Ambystoma tigrinum) and the mudpuppy (Necturus maculosus). Morphological characterization of these cells included three-dimensional reconstruction methods based on serial optical sections obtained with a confocal microscope. Some cells had their detailed morphology digitized with a computer-assisted tracing system and converted to compartmental models for computer simulations. The dendrites of ON-OFF amacrine cells have spines and numerous varicosities. Physiological recordings confirmed that ON-OFF amacrine cells generate both large- and small-amplitude impulses attributed, respectively, to somatic and dendritic generation sites. Using a multichannel model for impulse generation, computer simulations were carried out to evaluate how impulses are likely to propagate throughout these structures. We conclude that the ON-OFF amacrine cell is organized with multifocal dendritic impulse generating sites and that both dendritic and somatic impulse activity contribute to the functional repertoire of these interneurons: locally generated dendritic impulses can provide regional activation, while somatic impulse activity results in rapid activation of the entire dendritic tree.

Amacrine Cells↗

PubMed1985

Localization procedures in pheochromocytoma and neuroblastoma.

Localization procedures are required in catecholamine-producing tumors after clinical and biochemical confirmation. Computed tomography, ultrasound and/or 131I-metaiodobenzylguanidine (131I-MIBG) scintigraphy was performed in patients with pheochromocytoma, neuroblastoma and metastases of carcinoid tumors. Whereas computed tomography and ultrasound reflect morphological abnormalities, adrenomedullary scintigraphy depends on hormonal activity and other factors. 131I-MIBG scintigraphy has the advantage of detecting extraadrenal, multilocular and malignant pheochromocytomas. Especially small lesions and tumor tissue in bone marrow in children with neuroblastoma can be visualized more easily.

3-Iodobenzylguanidine↗