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Biomedical subjects

F Beltrame

Publications and source records attributed to F Beltrame.

52 records · Page 3Linked to original sources
PubMed1993

Confocal microscopy and cellular bioinformatics.

An exhaustive description of most biological data requires, besides a set of analytic information, an eidetic representation of the data itself. In this paper, two topics are presented. The first one is confocal microscopy, an advanced technique to produce multidimensional cellular and subcellular structures images. The second one is a software application, named BIOCELL, based on a relational database management system, developed to provide the biologist with an integrated tool to handle simultaneously cell biology linguistic and eidetic information.

Biotechnology↗
PubMed1992

Dystrophin at the plasma membrane of human muscle fibers shows a costameric localization.

We studied the distribution of dystrophin at the sarcolemma of normal human muscle fibers using high resolution immunofluorescence and confocal laser scanning optical microscopy (CLSOM). We found that the dystrophin lattice is organized at the muscle plasma membrane in an array of thick bands interconnected by a finer network. The bands encircle the muscle fiber perpendicular to the long axis of the fiber and they matched the sites of attachment of the sarcomeres to the plasma membrane. Dystrophin co-localized with vinculin, and dystrophin and vinculin co-localized with alpha-actinin at the region of the I-band. Dystrophin may be one of the proteins involved in the linkage of the sarcomeres to the extracellular matrix.

Actinin↗
PubMed1984

Automated analysis of living cells through the quantitative use of automated phase contrast microscopy.

A simplified theory of image formation in phase contrast microscopy is presented. It is shown that the phase shift induced in light (related to the refractive index) by the observed object can be reconstructed, point by point, from the phase-contrast digitally sampled image through an appropriate algorithm. This allows one to make quantitative observations on unstained, living cells.

Animals↗
PubMed1983

Higher-order structure of chromatin from resting cells. II. High-resolution computer analysis of native chromatin fibres and freeze-etching of nuclei from rat liver cells.

Non-destructive electron microscopy of native chromatin from rat liver nuclei reveals that the 30 nm fibre is formed of four 11 nm nucleofilaments, arranged in a coiled-coil (or rope-like) conformation. At low ionic strength, native fibres show an alternating pattern of compact and unwound regions. Freeze-etching experiments carried out on the same nuclei are compatible with the existence of periodic attachments of the fibres to the nuclear envelope near the pores in a regular, drapery-like fashion. For the first time, computer image analysis has been applied to electron micrographs of giant chromatin fibres and a few essential geometrical parameters characterizing the conformation of the higher-order structures have been determined. No significant difference has been found between calf thymus and rat liver chromatin.

Animals↗
PubMed1980

The quinternary chromatin-DNA structure. Three-dimensional reconstruction and functional significance.

Nuclear DNA-space images from Feulgen-stained HeLa cells synchronized at 1, 3, 5, 8, 12, 15, and 18 h following mitosis are digitized and their densitometric-geometric patterns are analyzed by means of a Quantimet 720-D image analyzer on line with a PDP11/40 computer. Frequency distributions of picture point optical densities for the phases and subphases as seen in nuclear images show that DNA packing changes are evident by means of ordinary optical microscopy. Radii of gyration of the images, and optical density profiles and distributions for several squashes of similar cells reveal that in particular instances chromatin DNA is distributed mostly towards the periphery, and usually with high circular isotropy. Cross power spectra of individual scan lines suggest that existence of higher order "quinternary" periodic structure for chromatin that modulates during the cell cycle. Three-dimensional reconstruction 2- micrometer sections of intact, Feulgen-stained mammalian tumor tissue show stainable material only toward the nuclear perimeter and not in the center (compatible with the evidence that initial thymidine incorporation in HeLa cells is generally at the nuclear border). Densitometric properties of reconstructed interphase chromatin-DNA bodies are highly coupled with similar properties of the whole nucleus, showing that a more condensed nucleus is always accompanied by a more condensed interphase chromatin DNA. The effect of micrococcal nuclease digestion on the digitized nuclear images is also presented. All the above data are then discussed in terms of a quinternary chromatin-DNA structure and its modulation during the cell cycle.

Cell Cycle↗
PubMed1979

Morphometric analysis of B2cAMP induced reverse transformation in synchronized CHO cells.

Synchronized tranformed and reverse-transformed (by 10(-3) M B2cAMP) CHO-K1 cells, growing adherent to plastic, are characterized by means of geometric and densitometric parameters at the level of both the entire cell and of the nuclei at various time intervals after selective miotic detachment. Transformed and reverse-transformed cells triple-stained with Feulgen, Napthol Yellow S, and periodic acid-Schiff appeared very similar in terms of integrated optical density (IOD), related to either polysaccharides, protein, or DNA amount. On the other hand, a shift from a polygonal to a spindle-shaped morphology is a accompanied by a significant decrease in both form factor and average optical density (AOD) of intact cell and nuclei, which are the most conspicuous measured changes caused by B2cAMP, in addition to a lengthening of the cell cycle duration. In both control and treated cells, important and parallel cell-cycle-dependent modulations of geometric and densitometric parameters are also observed, for both the cytoplasmic (i.e., cell morphometry) and DNA space (i e., nuclear morphometry). Specifically, the modulation in nulear morphometry during G1, S, G2, and M phases confirms previous findings on synchronized HeLa cells. The optical density threshold-dependence of geometric parameters shows that, while becoming fusiform, the cytoplasm of reverse-transformed cells had a particularly low optical density precisely in the polar area. Utilization of such an approach in the development of an objective morphological classification of all cell lines grown as monolayers "in vitro" is also discussed.

Animals↗
PubMed1979

Cytofluorometry of electromagnetically controlled cell dedifferentiation.

Cellular morphology changes, which appear related to dedifferentiation (despecialization), have been produced in vitro in the nucleated red blood cell of the frog. This has been achieved by controlled alterations in the electrochemical environment of these living cells, both by a selective modification of the ionic concentrations of an isotonic amphibian Ringer solution, and by the electromagnetic induction of pulsating current having specific waveform parameters. Laser flow microfluorometry shows that the modified Ringer solution is able, per se, to partially trigger the process in the same time interval that certain induced current waveforms can significantly affect the number of cells in the so-called dedifferentiated state. It has also been found that, for a given waveform, the repetition rate appears to have a significant effect on the rate of cell change. Preliminary automated image analysis of cell smears suggests that dedifferentiated and normal cells have the same integrated optical density but different nuclear areas. In conclusion, it appears that, after the initial electrochemical trigger, the early stage of the process, when the cells move from a state of specialized function to one of less specific activity, is the unfolding of their chromatin supercoil, not involving DNA synthesis. Then cytofluorometry allowed us to identify, for the first time, fundamental modifications which occur in the cell nucleus under electromagnetic exposure.

Acridine Orange↗
PubMedDate not supplied

Medical emergency aid through telematics: design, implementation guidelines and analysis of user requirements for the MERMAID project.

MERMAID is an EU financed telemedicine project with global reach and 24-h, multilingual capability. It aspires to provide a model for the provision of health care services based on the electronic transmission of medical information, via ISDN based videoconferencing. This model will not be limited to medical diagnostics but it will encompass all cases where the actual delivery of health care services involves a patient who is not located where the provider is. Its implementation requires the commissioning of an expensive telecommunications infrastructure and the exploration of a number of solutions. In fact, all categories of telemedical applications (audio and video conferencing, multimedia communications, flat file and image transfer with low, medium and high bandwidth data requirements) are considered while the full range of network choices (digital land lines, cellular/wireless, satellite and broadband) are being tested in terms of cost/performance tradeoffs that are inherent to them and the developmental stage each of these options occupies in their in its life cycle. Finally, out that MERMAID utilises advanced land based line transmission technologies to aid the remote patient by making available the specialist care that is best suited in the particular case.

Computers↗
PubMedDate not supplied

[Botulinum poisoning in adults: a case report and differential diagnosis].

The authors reports the case of a patient with quadriplegia associated with respiratory failure. A few days before, a paralysis of the oculomotor nerves appeared, which rapidly spreads in cranio-caudal fashion. The occurrence of a similar symptomatology in a patients' relative addressed the diagnosis toward a possible Clostridium botulinum intoxication. Other possible differential diagnoses are reviewed and discussed.

Botulism↗
PubMedDate not supplied

[Diagnostic image management and communication systems: experience at the University of Pisa].

Our work was aimed at implementing and validating a system for the acquisition, local management and remote transmission of diagnostic images. Integration of imaging equipment was performed in each of the two sites (5 km apart) in which the Department of Radiology of the University of Pisa is divided. Teleradiology was carried out using 64 Kbit/s lines as well as a 140 Mbit/s Metropolitan Area Network compliant with the Distributed Queue Dual Bus standard. Application domains included remote expert consultation and teleprocessing of diagnostic images. Remote expert consultation was performed in particular by using the 34 Mbit/s interconnection with the Metropolitan Area Network of Florence. Remote processing of diagnostic images using the high speed link allowed the cooperative work with scientific institutions in a field often limited by the complexity of image transfer and by the lack of a timely feed-back concerning the clinical value of processed images. Advanced processing of diagnostic images was performed in the field of stereographic display of CT and MR data sets. Moreover, experience was gained in the visualization, on a single composite image, of the multiparametric data obtained by means of different MR sequences (T1, Spin Density, T2), thus allowing to summarize, by using false colors, different tissue contrast information.

Computer Communication Networks↗