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PubMed1999

Progress and perspectives in computational neuroanatomy.

The tremendous increase in processing power of personal computers has recently allowed the construction of highly sophisticated models of neuronal function and behavior. Anatomy plays a fundamental role in supporting and shaping nervous system activity, yet to date most details of such a role have escaped the efforts of experimental and theoretical neuroscientists, mainly because of the problem's complexity. When accurate cellular morphologies are included in electrophysiological computer simulations, quantitative and qualitative effects of dendritic structure on firing properties can be extensively characterized. Complete models of dendritic morphology can be implemented to allow the computer generation of virtual neurons that model the anatomical characteristics of their real counterparts to a great degree of approximation. From a restricted and already available experimental database, stochastic and statistical algorithms can create an unlimited number of non-identical virtual neurons within several mammalian morphological classes, storing them in a compact and parsimonious format. When modeled neurons are distributed in three-dimensional and biologically plausible rules governing axonal navigation and connectivity are added to the simulations, entire portions of the nervous system can be "grown" as anatomically realistic neural networks. These computational constructs are useful to determine the influence of local geometry on system neuroanatomy, and to investigate systematically the mutual interactions between anatomical parameters and electrophysiological activity at the network level. A detailed computer model of a "virtual brain" that was truly equivalent to the biological structure could in principle allow scientists to carry out experiments that could not be performed on real nervous systems because of physical constraints. The computational approach to neuroanatomy is just at its beginning, but has a great potential to enhance the intuition of investigators and to aid neuroscience education. Anat Rec (New Anat): 257:195-207, 1999.

Animals↗

PubMed1980

[The use of contrast media in computer tomography (author's transl)].

There are a variety of applications for contrast media in CT. They can be used for better anatomic demonstration or for showing pathological processes. Nearly all available contrast media may be found useful. Intravenously injected renographic contrast media are most commonly employed. In addition to their inherent contrast, specific pharmaco-kinetic changes may be of diagnostic value. This adds some knowledge of function to the purely morphological information obtained by computer tomography. For this purpose, contrast has to be injected rapidly and a fast scanner must be used (so-called angio-CT).

Contrast Media↗

PubMed1999

Crystal morphology prediction and morphology variation in NaIO4 and NaIO4.3H2O.

Attachment energies computed with only Coulomb potentials have been utilized to predict crystal morphologies for NaIO(4), sodium iodate, and the hydrate NaIO(4).3H(2)O, sodium iodate trihydrate [actually Na(H(3)O)(IO(3))(OH)(3)]. As with other previously studied water-soluble ionic compounds, these two systems exhibit a systematic relationship between the early growth morphology and that of mature crystals; this relationship can in each case be reproduced by adjusting one attachment energy value. Morphology prediction for these two substances is of particular interest because NaIO(4).3H(2)O is a polar crystal and involves extensive hydrogen bonding, and because obtaining the observed morphology for NaIO(4) involved consideration of solvent desorption at the growing faces.

Journal Article↗

PubMed2001

Morphological aspects of the female pig bladder neck and urethra: quantitative analysis using computer assisted 3-dimensional reconstructions.

PURPOSE: To investigate whether the pig is a suitable model for studies of lower urinary tract function and dysfunction, we sought to determine the morphology of the female pig bladder neck and urethra. Computer assisted 3-dimensional (D) reconstructions from step serial histological sections were used for visualization of the spatial relationships between neighboring urethral wall components, and the quantification of these components in the bladder neck and along the urethra. MATERIALS AND METHODS: Step serial histological paraffin sections from the bladder neck and urethra of 6 female pigs, stained with Masson's trichrome, were used to generate computer assisted 3-D reconstructions using MacStereology (Ranfurly MicroSystems Ltd., Airdrie, United Kingdom) as the 3-D software package. RESULTS: The bladder neck and urethral anatomy revealed well defined smooth and striated muscle layers that varied in location, regional distribution and orientation. Circular smooth muscle was maximally developed in the mid urethra, at which point maximal urethral pressure was observed. The longitudinal smooth muscle layer appeared continuous with the detrusor, implicating a possible role in urethral shortening at the onset of voiding. A small circular and longitudinal striated muscle component was present in the distal urethra. CONCLUSIONS: Anatomical differences exist between the female pig and human bladder neck and urethra, which were successfully highlighted using computer assisted 3-D reconstructions from step serial histological paraffin sections.

Animals↗

PubMed1995

Can we teach psychiatric residents to rate seizure regularity?

Despite recent advances in electroconvulsive therapy, clinicians still lack a reliable marker of treatment adequacy. Electroencephalographic (EEG) seizure morphology has been proposed as such a marker. However, the reliability of seizure ratings has not been assessed. We present the results of a study that examined how readily psychiatric residents could be taught to rate seizure morphology using a seizure regularity scale. We found that trainees could reliably rate seizure regularity and were particularly adept at discerning highly regular seizures from irregular ones. We believe that establishing reliable human scoring for electroconvulsive therapy seizure regularity justifies the position that human inspection of the ictal EEG should always complement computer analyses of seizure morphology.

Adult↗

PubMed1999

Condylar bony change and craniofacial morphology in orthodontic patients with temporomandibular disorders (TMD) symptoms: a pilot study using helical computed tomography and magnetic resonance imaging.

OBJECTIVE: To investigate how condylar bony changes relate to craniofacial morphology using helical CT and MRI. DESIGN: Craniofacial morphology of orthodontic patients with condylar bony changes was compared with Japanese standard. SETTING AND SAMPLE POPULATION: The Department of Orthodontics, Niigata University School of Dentistry, Twenty-nine subjects were selected from orthodontic patients (six males and 23 females, a mean age of 18.8 +/- 6.3 years) who were diagnosed by helical CT as having condylar bony changes. EXPERIMENTAL VARIABLE: Subjects were divided into two groups: a unilateral condylar bony change group (unilateral group) (four males and nine females) and a bilateral condylar bony change group (bilateral group) (two males and 14 females). OUTCOME MEASURE: Condylar bony changes were evaluated on reconstructed coronal and sagittal CT scans. Disk positions were evaluated by MRI scans. Five linear and four angular measurements in lateral and posteroanterior cephalograms were compared with those of an age- and sex-matched 'standard population' from the Japanese standard. RESULTS: In the bilateral group, osteophyte formation and erosion were the common bony changes and were present in adult as well as juvenile subjects. In the unilateral group, flattening was the most common features and erosion was only present in subjects below 19 years. Disk displacement without reduction was seen in 90.6% of the bilateral group, and in 76.9% of the unilateral group. Retrognathic mandibles were shown in the bilateral group. All subjects exhibited a lateral shift of the menton toward the condylar bony changed side in the unilateral group. CONCLUSION: Condylar bony changes might be progressive and unstable in adults of the bilateral group as well as in juveniles of the both groups. It appears that condylar bony changes may be related to a lateral shift of the mandible and a retrognathic mandible in orthodontic patients with TMD symptoms.

Adolescent↗

PubMed1993

[An X-ray study of the incidence of asymptomatic hypertrophy of the coronoid process].

Although the coronoid process is not part of the temporomandibular joint, hyperplasia of the coronoid process can effect the mandibular movement as the result of the impingement on the zygomatic arch which is demonstrated in the case of a 22-year-old man. In order to access the prevalence of the asymptomatic enlargement of the coronoid process we carried out an investigation on 2000 panoramic radiographs and found only one case of a 64-year-old man. The very rare coronoid process abnormalities demonstrated on routine plan films should best be demonstrated in computed tomography, appreciating the morphology and the deformity of the surrounding structures.

Adult↗

PubMed2005

Computation of semantic similarity within an ontology of breast pathology to assist inter-observer consensus.

Computer-assisted consensus in medical imaging involves automatic comparison of morphological abnormalities observed by physicians in images. We built an ontology of morphological abnormalities in breast pathology to assist inter-observer consensus. Concepts of morphological abnormalities extracted from existing terminologies, published grading systems and medical reports were organized in an taxonomic hierarchy and furthermore linked by the relation "is a diagnostic criterion of" according to diagnostic meaning. We implemented position-based, content-based and mixed semantic similarity measures between concepts in this ontology and compared the results with experts' judgment. The position-based similarity measure using both taxonomic and non-taxonomic relations performed as well as the other measures and was used for automatic comparison of morphological abnormalities within the IDEM computer-assisted consensus platform.

Breast↗

PubMed2000

Growth hormone and thyrotropin hormone secretion in Alzheimer's disease.

The present study examined the relationship among GH and TSH secretion and neuropsychological and morphological tests in patients with Alzheimer's disease (AD). We studied 28 healthy controls and 28 AD patients with psychoneurological tests, and correlated their data with morphological data obtained by computed tomography and hormone responses of GH to GHRH, and TSH to TRH. The GH response to GHRH was higher in AD patients than in controls, 12.2 +/- 2 vs. 5.2 +/- 2.1 mcg/l, p< 0.01 but there was no difference in TSH response to TRH. On neuropsychological tests, patients were classified into 3 stages, these were indistinguishable on the basis of morphological data, GH and TSH responses at all stages including early-onset. Although GH response to GHRH was higher in AD patients than in controls, our results suggest that psychometric discrimination may be more accurate in diagnosis and staging of AD, than in predicting by morphological and hormonal responses.

Aged↗

PubMed2001

Cultured pulp fibroblasts: are they suitable for in vitro cytotoxicity testing?

The use of cell cultures to test the biocompatibility of dental materials is gaining in importance. Any cytotoxic effects that restorative materials may have will be on the dental pulp and for that reason cultured pulp cells should be the model of choice for biocompatibility testing. The aim of this investigation was to study the growth and morphologic characteristics and toxic response of human pulp lines and to compare these parameters to those of human buccal mucosa fibroblasts. Twenty-one specimens of pulp tissue and six from buccal mucosa were cultured using standard techniques. Six pulp cell lines were cultured successfully as were all six from the buccal mucosa specimens. From these specimens, 12 growth curves were computed. To study the morphology of the cultured cells, they were observed microscopically and classified into three morphological types: slender elongated cells (type I), epithelioid shaped cells (type II) and large stellate cells (type III). Their numbers and proportions were determined for each cell line and compared statistically. To gauge sensitivity to toxic materials, cells were exposed to concentrations of arecoline. An analysis of the growth curves showed no statistical difference between pulp cells and buccal mucosa cells; the slopes of the curves, however, differed significantly between individual cell lines, and these individual differences were greater among pulp cell lines. The morphology of the pulp and mucosa fibroblasts was similar microscopically. There was no significant difference between the number and proportion of the cell types in the two groups, but there were significant differences between the individual cell lines. Pulp cells showed a greater inhibition of growth when exposed to arecoline. Because pulp fibroblasts are difficult to culture, their reported survival rate is poor; due to the differences that exist between individual cell lines, we conclude that pulp cells when used as single cell lines or even pooled may not be ideal for testing biocompatibility, especially if reproducibility is a prerequisite. Any evaluation will require tests on not one, but several cell lines in order to minimize the effect of inter-cell-line differences. Their greater sensitivity to toxic substances, on the other hand, may show that pulp cells could be more sensitive indicators of cytotoxicity.

Adult↗

PubMed1992

PET correlates of normal and impaired memory functions.

To date, positron emission tomography (PET) has been the only technology for the quantitative imaging of the changes of regional cerebral glucose (rCMRGl) or oxygen metabolism and blood flow (rCBF) associated with psychophysical stimulation and with the performance of mental tasks. So far, the majority of studies performed in healthy subjects demonstrated activation patterns involving not only certain limbic structures, most of all hippocampus, amygdala, parahippocampus, and cingulate, but also temporal, parietal, and occipital association cortex, depending on the applied paradigm. Indeed, the closest correlation between regional metabolism and memory test scores was found in mesiotemporal structures during the performance of memory tasks. Metabolic or CBF studies also seem to indicate that memorizing strategies may differ among individuals. PET was repeatedly used to investigate metabolic and/or blood flow abnormalities in patients with various amnestic syndromes. In cases with uni- or bilateral lesions of mesiotemporal structures, caused by surgery, herpes simplex encephalitis, or permanent ischemic, anoxic, or toxic damage, disturbances of metabolism and blood flow typically extended far beyond the morphological defects detected by computed tomography or magnetic resonance. In acute transient global amnesia, CBF and metabolism were decreased bilaterally in the mesiotemporal lobes, where hypometabolism persisted for some time, while higher values were observed in thalamus and some cortical areas. Diencephalic lesions causing Korsakoff's syndrome were associated with decreased rCMRGl in the hippocampal formation, upper brainstem, cingulate, and thalamus. Discrete thalamic infarcts caused amnesia and metabolic depression in the morphologically intact ipsilateral thalamus and in various projection areas of the infarcted nuclei. In ischemic forebrain lesions, amnestic deficits could be related to involvement of the anterior cingulate and of basal cholinergic nuclei. A large number of pathologies are diffusely spread out in the brain and affect partially or predominantly structures in memory processing. This holds true especially in the various dementias where memory disturbances are a consistent and often leading feature. Notably, Alzheimer's disease can be distinguished from other dementias by its characteristic pattern of metabolic dysfunction, with the most prominent changes occurring in parietotemporal and frontal association cortex whose residual metabolism is related to the severity of the disease. Therefore, activation studies using paradigms involving memory functions enhance that typical pattern. Only in the activated state is metabolism of mesiotemporal structures significantly correlated with the performance in memory tests. Other dementias also affect some of the distributed memory networks, with Huntington's disease suggesting a role of the striatum in memory processing.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed2004

Computer simulation of the influence of cellular adhesion on the morphology of the interface between tissues of proliferating and quiescent cells.

We investigate the influence of cellular adhesion on the morphology of the interface between a tissue of proliferating and quiescent cells using the cellular Potts model. We show that a decrease in surface tension changes the morphology of the interface and that only for negative surface tensions cell detachment from the proliferative tissue occurs suggesting that this might be a necessary condition for metastatization in malignant neoplasies.

Algorithms↗

PubMed2004

Chlamydiae in the ejaculate: their influence on the quality and morphology of sperm.

BACKGROUND: Given the lack of information concerning the role of Chlamydia trachomatis in male fertility, the aim of this study was to ascertain and analyze the quality of Chlamydiae-positive and -negative semen. MATERIAL AND METHODS: Sperm count was performed according to the 1999 World Health Organization (WHO) laboratory manual for examination of human semen and sperm-cervical mucus interaction, and sperm survival was assessed by a 120-min test. The evaluation of the morphological examination of ejaculates was carried out using the sasmo (strict morphological analysis of ejaculates) computer program. Chlamydiae were detected by immunofluorescent reaction using the Progen Biotechnik GmbH diagnostic set. Fisher's exact test and the chi-quadrate test were used for statistical analysis. RESULTS: Of the total of 627 sperm samples examined, Chlamydiae were detected in 136 cases (21.7%). Sperm analysis showed significant differences between Chlamydiae-positive and -negative samples. The Chlamydiae-contaminated group showed normal sperm morphology 14.4% lower, volume 6.4% lower, concentration 8.3% lower, motility 7.8% and velocity 9.3% lower than in Chlamydiae-negative samples. The average values for normal spermatozoa and motility in the Chlamydiae-positive group were also significantly reduced. CONCLUSION: Chlamydia trachomatis was found to be a possible factor in sperm pathology. These results could help to elucidate the role of Chlamydia trachomatis in male infertility.

Chlamydia Infections↗

PubMed1983

[A pulsating tumor in the chest wall].

A pericardial constriction with calcification and a pulsating cyst is an unusual outcome after a pericardial windowing. The application of cardiac computed tomography evaluating the morphological parameters of the heart chambers and the adjacent vessels is an appropriate noninvasive method in the diagnostics of pericardial constriction.

Abscess↗

PubMed1994

A large painful Schmorl's node: a case report.

A 27-year-old woman presented with a 2-week history of low back pain and an unusually large Schmorl's node in the third lumbar vertebra. She reported no previous low back symptoms. Initially, a malignant spinal tumor was suspected because of the irregular osteolytic changes on the computed tomograms and high uptake with technetium bone mineral scanning. The lesion was subsequently diagnosed by discography as a Schmorl's node. The patient has now been followed for 3 years. At the time of this writing, she has been without low back symptoms or signs. Using serial computed tomography, we observed morphological changes in the Schmorl's node that were similar to those processes observed with fracture healing.

Adult↗

PubMed2003

Computer-assisted reconstruction and motion analysis of the three-dimensional cell.

Even though several microscopic techniques provide three-dimensional (3D) information on fixed and living cells, the perception persists that cells are two-dimensional (2D). Cells are, in fact, 3D and their behavior, including the extension of pseudopods, includes an important 3D component. Although treating the cell as a 2D entity has proven effective in understanding how cells locomote, and in identifying defects in a variety of mutant and abnormal cells, there are cases in which 3D reconstruction and analysis are essential. Here, we describe advanced computer-assisted 3D reconstruction and motion analysis programs for both individual live, crawling cells and developing embryos. These systems (3D-DIAS, 3D-DIASemb) can be used to reconstruct and motion analyze at short time intervals the nucleus and pseudopodia as well as the entire surface of a single migrating cell, or every cell and nucleus in a developing embryo. Because all images are converted to mathematical representations, a variety of motility and dynamic morphology parameters can be computed that have proven quite valuable in the identification of mutant behaviors. We also describe examples of mutant behaviors in Dictyostelium that were revealed through 3D analysis.

Animals↗

PubMed1995

The use of computers in understanding how animal cells crawl.

Amoeboid cell motility is a complex three-dimensional process which involves pseudopod expansion, cellular translocation, and, in some cases, pseudopod retraction and complex interactions between the ventral surface of the pseudopod and substratum. In order to quantify the basic behavior of amoeboid cells and the dynamics of pseudopod extension and retraction, sophisticated two-dimensional and three-dimensional computer-assisted motion analysis systems have been developed which reconstruct digitized images and compute motility and dynamics morphology parameters. These systems provide a wealth of information of how amoeboid cells crawl and they have begun to be utilized (1) to elucidate the basic rules of amoeboid movement, (2) to identify the behavioral defects of cytoskeletal mutants, and (3) to elucidate the mechanism of chemotaxis. In addition, these systems represent powerful tools for analyzing the effects of drugs on cell behavior, most notably that of white blood cells and neoplastic cells. Since computer-assisted motion analysis is a relatively young field, the technologies are still evolving and have been underutilized in most areas involving cell motility. This review, which includes a description of these technologies and examples of their application, will hopefully serve as an impetus for expanded use.

Animals↗

PubMed1992

An interactive image analysis system for quantitative cytology & to classify cervical cells.

Introduction of computers and image analysis systems are gaining faster momentum in order to quantitate the assessment of cells for diagnosis and prognosis, and this system aims to relieve the operator from the tedium of microscopic observation and reduce operator bias and human error. This paper discusses the design and configuration of an interactive image analysis system built in the laboratory for the purpose of cell analysis and classification. The software developed to compute various textural and morphological parameters of cells on smear are briefly described. The results of the experiments carried out to classify normal and abnormal cells on cervical smear show 94 per cent success rate.

Cytological Techniques↗