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Biomedical subjects

A Shahar

Publications and source records attributed to A Shahar.

At least 91 records · Page 5Linked to original sources
PubMed1985

Production of herpesvirus of turkeys in microcarrier culturing system--a new method for production of vaccine against Marek's disease.

A microcarrier (MC) culturing system for production of a vaccine against Marek's disease virus is presented. Cytodex-3 beads (Pharmacia) and DE-53 microgranular (Whatman) are the recommended microcarriers. Primary cells from chick embryo as well as cells from a quail cell line (QT-6, established from a Japanese quail) were found to be good hosts for growth of herpesvirus of turkeys (HVT). HVT, the vaccine strain against Marek's disease, was successfully grown and harvested on the above mentioned MCs and cells. The findings of this study, open new possibilities in the production of HVT for various purposes such as basic research and vaccine preparation.

Animals↗
PubMed1985

Ion exchange capacity of DEAE microcarriers determined the growth pattern of cells in culture.

Transformed embryonic avian and mammalian cells, as well as cells from established cell lines grow as a monolayer on DEAE-cellulose based microcarriers (MC): the DE-52 and DE-53 MC. Normal, non-transformed, embryonic avian and mammalian cells do not grow on DE-52 MC (having an exchange capacity of 1 meq/g dry material) but grow well on DE-53 MC (having an exchange capacity of 2 meq/g dry material). On DE-53 MC embryonic non-transformed cells grow in multilayers, while embryonic viral-transformed cells and cells from established cell lines grow in a monolayer form. Possible explanations for the differences in cell growth on various MC and variation in the mode of growth in monolayer vs multilayer are discussed. These differences may serve as a valuable tool for separation and distinction between normal and transformed cells. In addition, the described novel MC culturing system provides a support for tridimensional growth on which cell growth mimics the in vivo growth conditions. Therefore, this system is suitable for the study of cell recognition, cell to cell connection and cell orientation.

Animals↗
PubMed1985

Differentiation of myoblasts with nerve cells on microcarriers in culture.

Differentiation of embryonic rat and chick myoblasts was investigated using a tridimensional support made of positively charged, uncoated DEAE-cellulose microcarriers (MC). Following rapid cell attachment, the MC interconnected to form large cell-MC conglomerates which remained floating in the nutrient medium. Cells within the conglomerates fused to form myotubes which synthesized muscle-specific proteins such as: creatine kinase, acetylcholinesterase, acetylcholine receptors, and contracted in response to electrical stimulation. Myotubes, at different stages of differentiation, showed characteristic morphology (as observed by transmission and scanning electron-microscopies). Upon addition of dissociated spinal cord cells to these muscle-MC cultures, intensive sprouting of nerve fibres took place. After a few days an extensive network of nerve fibres was formed on the top of muscle myotubes and nerve-muscle contacts were established.

Animals↗
PubMed1985

RDB--a new product of plant origin for cell culture dispersion.

RDB is a crude preparation extracted from a plant source. It is a very potent agent for dispersion of monolayer cell cultures as well as for the preparation of primary cell suspensions. It was found to be most effective in dispersing a wide range of animal and mosquito cells and dissociating neuronal and muscular tissue for primary cell cultures. RDB was also found to be useful for preparation of primary culture for chick embryo fibroblasts. After treatment with RDB cell viability was found to be 98% as compared to 85% in trypsin treated monolayer cultures. Routine dispersion of monolayer cultures with RDB does not have any negative effect on confluency of the newly split cultures. RDB was found to have no adverse effects on viral replication and plating efficiency of Rift Valley Fever Virus, Sindbis Virus and West Nile Virus.

Animals↗
PubMed1984

A simplified microwell pseudoreplica for the detection of viruses by electron microscopy and immunoelectron microscopy.

Simplified procedures for immunoelectron microscopy (IEM) and electron microscopy (EM) are described. The procedures employ the principle of agar filtration and pseudoreplication. The modification consisted of the use of microwells for storage of gels with or without antiserum (for IEM or EM, respectively) and an array of containers in which pseudoreplication and negative staining were performed. The containers were prepared from 5 ml syringes from which the needle holding parts were cut. This device enabled simultaneous and rapid handling of specimens. With Sindbis virus as a model, our microwell pseudoreplica IEM (MW-PR-IEM) was compared to six other IEM techniques and was found to be the most rapid and sensitive technique. With the MW-PR-IEM technique, the specific minimal detection limit (detection of clumps) was 1.5 x 10(7) virus particles per ml, and the non-specific detection limit (detection of single virions) was 1.8 x 10(6) virus particles per ml.

Antibodies, Viral↗
PubMed1984

Role of substrata in determining the growth topology of transformed and nontransformed cells in culture.

Cylindrical DEAE cellulose anion exchangers (DE-53), generally used for chromatography, were found suitable as a substratum for cultivating cells. Embryonic avian and mammalian cells cultured on DE-53 microcarriers (MC) grow in multilayers, while the same embryonic cells when transformed by avian sarcoma virus (ASV) grow in monolayers. These patterns of cell growth differ from those of normal and transformed cells grown on conventional glass or plastic Petri dishes, or on beaded MC. Cells derived from established cell lines such as BHK, HeLa, L-929, MDCK, and VERO grow in monolayer on these MC. A human adenocarcinoma cell line is the only exception growing in a multilayer form. These results indicate that the ability of cultured cells to grow in multilayers, is determined not only by their state of transformation but also by the properties of the support on which they are cultured.

Adenocarcinoma↗
PubMed1984

Tinnitus asymmetry.

In the present study, the relationship between the location of tinnitus and the location of the greater hearing impairment was investigated. 62 subjects suffering from tinnitus underwent audiometric testing and were required to identify the location of their tinnitus. All of the subjects had a history of exposure to loud noise. The results of the study showed an asymmetric relationship between the variables examined. Most of the subjects with a greater hearing loss on the right side reported right-sided tinnitus, while the majority of subjects with a greater loss in the left ear reported tinnitus heard identically in both ears or tinnitus heard louder on the right side. An assumption was made that this phenomenon is related to differential hemispheric responsiveness to abnormal neural activity arising in the peripheral parts of the auditory system as a result of cochlear damage, activity which is the presumed origin of neurogenic tinnitus.

Adult↗
PubMed1983

Synaptogenesis and myelination in dissociated cerebral microcarrier cell cultures.

A new approach for cultivating dissociated cerebral neurons is described. It is based on a rapid attachment of neurons to the DEAE-cellulose cylindrical MC and their subsequent interconnection to form cell-MC conglomerates. Intensive fiber growth followed by synaptogenesis and progressive myelin formation are indicative of optimal conditions of nutrition and oxygenation.

Acetylcholinesterase↗
PubMed1983

Cultures of central neurons grown in the presence of phencyclidine.

In order to study the mode of action of phencyclidine at the cellular level differentiating cultures of dissociated nerve cells from brain and spinal cord have been used. Cells were grown in the presence of 50-500 microM of PCP or tritium labelled PCP, for the periods of 1-11 days. PCP in the concentration of 500 microM caused progressive degeneration of nerve cells, already noticeable after 24 h. No significant morphological changes were observed in cells exposed to PCP at concentrations up to 200 microM. In brain cultures exposed to 200 microM PCP, 50% decrease of AChE activity was observed. No decrease in enzyme activity was found in cultures of spinal cord.

Acetylcholinesterase↗
PubMed1983

Correlation between chemiluminescence response and rate of zymosan uptake by rat alveolar macrophages. Scanning electron microscope observations.

The rate of particle uptake by rat alveolar macrophages (AM) exposed to zymosan (mean number of zymosan particles becoming bound to 100 cells at a fixed time interval) was determined with the aid of the scanning electron microscope (SEM). The intensity of the chemiluminescence (CL) emitted by the AM on addition of zymosan, was measured concomitantly. During the whole course of CL emission, all the particles were found to be either attached or engulfed, but not ingested by the AM. A good correlation was obtained between the time dependence of CL intensity and that of the rate of particle uptake, both reaching a peak value at about 5 min after exposure. It is therefore assumed that the CL emitted by AM exposed to zymosan reflects the attachment and engulfment stages of phagocytosis.

Animals↗
PubMed1983

Myogenesis on microcarrier cultures.

The capacity of embryonic chick myoblasts to grow in vitro on DEAE-cellulose microcarriers (MC) has been investigated biochemically and morphologically. The cells attached to the MC, replicated and fused to form elongated myotubes. These myotubes synthesized muscle-specific proteins, such as creatine kinase (CK) and acetylcholine receptors (AChR), and they contracted spontaneously. Some of the advantages of this technique are: a) Tridimensional development of myotubes on MC with orientation of fibers parallel to each other; b) Muscle cells can be cultured on MC for long periods (months); c) Easy harvesting of samples at any time during cultivation; d) DEAE-cellulose MC are commercially available, inexpensive and easy to handle.

Animals↗
PubMed1983

The treatment of social dysfunction in nonpsychotic outpatients. A review.

A sizable proportion (7 to 16 per cent) of psychiatric outpatients suffer from social dysfunction, either as the main complaint or in conjunction with other psychiatric problems. Social skills training is a newly evolved treatment regimen that involves teaching patients new forms of social behavior by their rehearsal within sessions and their practice in real life between sessions. In an overview of controlled studies, social skills training was found to have been useful for up to 16 months follow-up in mainly nonpsychotic socially dysfunctional outpatients. Its effects supersede "no-treatment" periods and it appears a more potent treatment of social dysfunction than contrasting methods such as short term psychotherapy, systematic desensitization, sensitivity training, etc. The adjunct use of an anxiolytic or cognitive modification has not enhanced outcome. Social skills training is recommended as the treatment of choice for patients with social dysfunction, especially when no other major psychiatric disorders are present.

Ambulatory Care↗
PubMed1983

Tinnitus pitch and acoustic trauma.

56 Subjects complaining of tinnitus underwent an audiometric test and a test for identifying the analogous pitch of their tinnitus. All of the subjects reported that they had been exposed to noise in the past. The subjects were divided into two groups on the basis of their audiometric test results. Group P was composed of subjects who showed a sensorineural hearing loss typical of acoustic trauma. Group N was composed of subjects whose hearing was within normal limits. The pitch of the tinnitus in group P was concentrated in the high-frequency range, whereas in group N tinnitus pitch values were distributed over the low and mid-audiometric frequency spectrum. It was deduced that different processes are involved in the generation of tinnitus in the two groups.

Adult↗
PubMed1983

Neuronal cultures on microcarriers: dissociated spinal cord cells.

Dissociated spinal cord cells from rat fetuses were successfully cultured up to the state of synaptogenesis and myelin formation on DEAE cellulose cylindrical microcarriers. Nerve cells and microcarriers interconnected to form conglomerates offering optimal nutritional conditions which enhanced cell maturation. These conglomerates yielded large amounts of cells which could easily be harvested for biochemical analysis.

Animals↗
PubMed1983

Human epithelial cell line established from a child with juvenile laryngeal papillomatosis.

Papillae were removed from a 2-yr-old boy with juvenile squamous cell papillomatosis and the tissue was grown in vitro. The method leading to the establishment of a continuous laryngeal papilloma cell line is described. This epithelial cell line was benign, as judged by cell morphology and cellular inability to form colonies in soft agar or to produce growing nodules in nude mice. Papilloma virus particles were not seen through the electron microscope. In the early stages of culture, the cells contained antigen that stained specifically with autologous serum.

Cell Line↗
PubMed1982

DE-52 and DE-53 cellulose microcarriers. I. Growth of primary and established anchorage-dependent cells.

DEAE cellulose anion exchangers having small ion exchange capacity (0.5 to 2.0 meq/g dry material) were tested for cell attachment kinetics and capacity to support growth anchorage-dependent cells. It was found that cells from established cell lines (BHK and MDCK) can grow to confluency on DEAE cellulose particles having exchange capacity of 1 and 2 meq/g dry materials, DE-52 and DE-53, respectively. On the other hand, chick embryo fibroblasts (primary cells) can grow only on DE-53 particles.

Animals↗