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Biomedical subjects

A Berezin

Publications and source records attributed to A Berezin.

At least 19 recordsLinked to original sources
PubMed2000

Individual cell motility studied by time-lapse video recording: influence of experimental conditions.

BACKGROUND: Eukaryotic cell motility plays a key role during development, wound healing, and tumour invasion. Computer-assisted image analysis now makes it a realistic task to quantify individual cell motility of a large number of cells. However, the influence of culture conditions before and during measurements has not been investigated systematically. METHODS: We have evaluated intraassay and interassay variations in determinations of cellular speed of fibroblastoid L929 cells and investigated the effects of a series of physical and biological parameters on the motile behavior of this cell line. Cellular morphology and organization of filamentous actin were assessed by means of phase-contrast and confocal laser scanning microscopy and compared to the corresponding motility data. RESULTS: Cell dissociation procedure, seeding density, time of cultivation, and substrate concentration were shown to affect cellular speed significantly. pH and temperature of the medium most profoundly influenced cell motility and morphology. Thus, the mean cell speed was 40% lower at pH 7.25 than at pH 7.6; at 29 degrees C, it was approximately four times lower than at 39 degrees C. CONCLUSION: Of the parameters evaluated, cell motility was most strongly affected by changes in pH and temperature. In general, changes in cell speed were accompanied by alterations in cell morphology and organization of filamentous actin, although no consistent phenotypic characteristics could be demonstrated for cells exhibiting high cell speed.

Actins↗
PubMed2000

A simple procedure for quantification of neurite outgrowth based on stereological principles.

The molecular mechanisms controlling formation and remodelling of neuronal extensions are of considerable interest for the understanding of neuronal development and plasticity. Determination of neurite outgrowth in cell culture is a widely used approach to investigate these phenomena. This is generally done by a time consuming tracing of individual neurites and their branches. We have used stereological principles to determine the length of neurites. The total neuritic length per cell was estimated by counting the number of intersections between neurites and test lines of an unbiased counting frame superimposed on images of cell cultures obtained by conventional computer-assisted microscopy. The absolute length, L, of neurites per cell was subsequently estimated from the number of neurite intersections, I, per cell by means of the equation L=(pid/2)I describing the relationship between the number of neurite intersections and the vertical distance, d, between the test lines used. When measuring neurite outgrowth from PC12 cells and primary hippocampal neurons, data obtained by counting neuritic intersections correlated statistically significantly with data obtained using a conventional tracing technique. However, information was acquired more efficiently using the stereological approach. Thus, using the described set-up, the stereological procedure was approximately five times less time consuming than the conventional method based on neurite tracing. The study shows that stereological estimation of neuritic length provides a precise and efficient method for the study of neurite outgrowth in cultures of primary neurons and cell lines.

Animals↗
PubMed1998

A simple procedure for morphometric analysis of processes and growth cones of neurons in culture using parameters derived from the contour and convex hull of the object.

Morphometric estimation of neuronal processes is currently laborious and time-consuming, since the individual processes (axons and dendrites) have to be traced manually. In order to facilitate the measurement of cellular processes, we have tested a series of parameters derived from the contour and the convex hull of an object and estimated to which extent they reflect process length and number. The parameters included the area, perimeter and form factor of the object and convex hull, their ratios as well as object length, breadth, width, length/width and spreading index. Some new parameters derived from the contour and convex hull of the object, were also computed: process index (the number of areas contained within the convex hull outside the object contour), process domain (the total area contained within the convex hull outside the object contour), their ratio and the square root of the process domain (SR process domain). In total, 18 parameters were estimated. Populations of motoneurons, growth cones of cerebellar granule cells and N2a neuroblastoma cells were utilized due to their diversity in morphological features. The processes of each object were drawn by hand to establish the actual length and number. Total process length per object correlated strongly with object perimeter, process domain and SR process domain. The number of processes per object correlated well with perimeter ratio, process index and form factor, whereas object length, convex hull perimeter and spreading index correlated acceptably with the average process length. Using these parameters for the evaluation of neurite outgrowth in developing of hippocampal neurons in vitro, variables such as object perimeter, process domain and SR process domain were found to be very well suited for estimation of the total length of neurites. We conclude that based on the contour and convex hull of an object it is possible to calculate a series of parameters which may substitute direct measurements of process length.

Animals↗
PubMed1998

Cell motility is inhibited by the antiepileptic compound, valproic acid and its teratogenic analogues.

Valproic acid (VPA) is an established human teratogen that causes neural tube defects in 1-2% of human foetuses exposed to the drug during early pregnancy. In this study, individual cell motility was evaluated using short- and long-term time-lapse video-recording and computer assisted image analysis, and it was found that VPA and selected VPA-analogues inhibited individual cell motility of L-cells in a dose-dependent manner. The compounds caused a decrease in the root-mean-square speed, S, and in the rate of diffusion, R, but an increase in the time of persistence in direction, P. Using short-term recordings and measurements of mean-cell speed, the reduction in the motile behaviour was shown to correlate with the teratogenic potency of the tested compounds. The observed effects of VPA on cell motility was independent of the employed L-cell clone, and could be reproduced in cells containing the neuronal marker NCAM and in the neuronal cell line N2a. Furthermore, the observed effect was independent of culture substratum, being observed for L-cells grown on fibronectin as well as on plastic. Immunofluorescence microscopy revealed that VPA-treatment of mouse L-cells caused a redistribution of F-actin and of a series of focal adhesion proteins, indicating that the effect of VPA on cell motility may be causally related to increased cell-substratum interactions or to alterations in the organisation or dynamics of the actin cytoskeleton.

Animals↗
PubMed1989

[Solacy and non-specific chronic laryngitis].

Adult subjects, without age or sex distinction, presenting a non-specific chronic laryngitis were treated with SOLACY. The posology of SOLACY administered was: 2 capsules in the morning and 2 at night for four months in a row. The subjects were seen at least twice: one consultation before the treatment and one after the 4 months of treatment. These consultations included an interview and fibroscopic test of the laryngeal mucosa (photographs were taken). The subjects were also requested to quantify the overall discomfort experienced. Ten subjects were recruited for this study. Dysphonia was significantly lower after the 4-month treatment as was the self-evaluation of the overall discomfort brought on by the different symptoms. In addition, it can be noted that SOLACY lessened coughing and laryngeal discomfort in most of the patients treated and it improved the fibroscopic test results, especially concerning the congestive aspect of the laryngeal mucosa, whether limited to vocal chords or spread throughout the entire vestibule. The treatment was tolerated perfectly well. In conclusion, SOLACY, administered in adults presenting non-specific chronic laryngitis improves the state of the laryngeal mucosa and its main symptoms (dysphonia, coughing, laryngeal discomfort).

Adult↗
PubMed1988

A search for narrow band signals with SERENDIP II: a progress report.

Commensal programs for the Search for Extraterrestrial Intelligence (SETI), carried out concurrently with conventional radio astronomical observing programs, can be an attractive and cost-effective means of exploring the large multidimensional search space intrinsic to this effort. Our automated commensal system, SERENDIP II, is a high resolution 131,072 channel spectrometer. It searches for 0.49 Hz signals in sequential 64,700 Hz bands of the IF signal from a radio telescope being used for an astronomical observation. Upon detection of a narrow band signal with power above a preset threshold, the frequency, power, time, and telescope direction are recorded for later study. The system has been tested at the Hat Creek Radio Astronomy Observatory 85 ft telescope and the NASA-JPL Deep Space Station (DSS 14) 64 m telescope. It is currently collecting data at the National Radio Astronomy Observatory 300 ft telescope.

Astronomy↗
PubMed1988

[Rhinoseptoplasty in patients from the Maison de Nanterre. Indications, technics and results].

There are many indications of rhinoseptoplasty for patients of ENT department in the hospital of the "Maison de Nanterre". Must frequently we have to manage sequellae of nasal traumatisms (consequences of fights or falls). Aesthetic rhinoplasties are less frequent: nasal deformities from ethnic or familial origin. The operatory technic used is very classic: septoplasty as the first step, then rhinoplasty by extra mucosal way, with paramedial and lateral osteotomies allowing rebuilding of nasal osseous pyramid. Results as well on anatomic and functional point of view as on psychologic consequences are arguments to be interventionist.

Humans↗
PubMed1985

[Concentrations of antibiotics (josamycin, trioleandomycin and amoxicillin) in the secretions of the ear, sinus and adenoids].

This was a comparative study of antibiotics in the pus of otitis and from the sinuses as well as in the adenoids. Three antibiotics were chosen: Trioleandomycin, Josamycin, Amoxicillin. The study protocol was strict. Results obtained were as follows: high concentrations of macrolids in discharge of otitis and the sinuses as well as in the adenoids. Concentrations were higher than serum concentrations. By contrast, in the case of amoxicillin tissue concentrations were lower than the serum concentration. This leads to the conclusion that there is good penetration of infectious ENT sites by macrolids.

Adenoids↗
PubMed1981

[Ankylosis of the stapes by post-inflammatory osteogenesis (or syndrome of Coyle Shea Jr). Report of two cases (author's transl)].

Ankylosis of the stapes by post-inflammatory osteogenesis (syndrome of Coyle Shea Jr) is a pathologic entity still not well known, often confounded with otosclerosis. If surgical treatment is the same as for otosclerosis (stopedectomy, platinectomy, veinous graft and piston), the prognosis is not the same and a great carefulness is necessary, as well in operatory indications as in operatory procedure itself.

Adult↗
PubMed1978

Electron microscopy of lamellated osmiophilic bodies in granular pneumocytes of the toad (Bufo icterus icterus) in an advanced stage of dehydration and after rehydration.

The effects of body dehydration on the ultrastructural pattern of lamellated osmiophilic bodies of granular pneumocytes of toads were investigated until almost complete absence of these bodies after 40 per cent body weight loss. The presence of lamellated osmiophilic bodies after rehydration would strongly indicate that water has a great influence upon the secretion of these structures.

Animals↗