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PubMed1988

The influence of synovial fluids from patients with rheumatic diseases on chick embryo fibroblasts.

Primary chick-embryo fibroblasts (PCEF) were used as target cells to measure the influence of synovial fluids of patients suffering from osteoarthritis (OA; n = 5), rheumatoid arthritis (RA; n = 12) and psoriatic arthritis (PA; n = 2). The following metabolic cell products were measured: DNA, RNA, glycosaminoglycans (GAG), sulfated glycosaminoglycans, protein and collagen, with the same joint effusions being used in each test. Since it is not a single substance that provokes a stimulating or inhibiting effect in the joint, the crude synovial fluids were applied in these preliminary experiments. It was found that each type of synovial fluid showed an influence on the biological processes in the PCEF. The DNA, RNA and GAG syntheses were strongly influenced by the joint effusions, in contrast to the protein, collagen and sulfated glycosaminoglycan syntheses which were less affected. Generally, the nucleic acid synthesis differed significantly between the OA, RA and PA synovial fluids. The addition of heparin to the synovial fluids caused an additive inhibiting effect on the DNA synthesis but did not influence the other biochemical parameters. The synovial fluids of RA patients, and to a much greater extent those of PA patients, inhibited the thymidine incorporation whereas OA synovial fluids had a less pronounced effect. This result indicates a disease-dependent composition of the synovial fluids. RNA synthesis was diminished in all three groups, but again this effect was strongest in the case of the PA synovial fluids. GAG synthesis was markedly stimulated by the PA synovial fluids and somewhat, though to a lesser extent, by the OA and RA synovial fluids. The sulfated glycosaminoglycan synthesis in the PCEF, as revealed by 35S incorporation into the GAG, was less influenced and on the whole stimulated by the OA and RA synovial fluids. The same trend could be observed with regard to the collagen synthesis. The intracellular protein synthesis was less influenced by the OA (91.9%) and more strongly suppressed by the RA (78.7%) and the PA (76.7%) synovial fluids. PCEF therefore appear to be a convenient and sensitive target cell system to study alterations of biochemical processes caused by crude synovial fluids and also of different origin by individual factors isolated from synovial fluids.

Animals↗

PubMed2003

Follicle-stimulating hormone increases cell proliferation in the ovary and the testis of the chick embryo.

Previous studies have demonstrated that FSH stimulates cell proliferation in the ovary and the testis of the chick embryo. This study analyzed the presence of FSH receptor and the cell subpopulations that proliferate in response to FSH in chick embryo gonads. FSH receptor mRNA was detected by reverse transcription-polymerase chain reaction (RT-PCR) in the male and female gonads of the 6 to 14-day-old chick embryo. Somatic cells of the ovary expressed the FSH receptor in the 14-day-old chick embryo. Ovarian surface epithelium of the 14-day-old chick embryo increased the mitotic index 15-18 h after FSH treatment. Similarly, the mitotic index in oogonia was increased 24 h after receiving a pulse of FSH; this result was confirmed by an increase in the number of germ cells that incorporated bromodeoxyuridine (BrdU). Somatic cells of the medullary cords in the ovary displayed an increase in the mitotic index 15-21 h after the FSH injection. In the chick embryo testis, at the same stage of development, the treatment with FSH increased the mitotic index in cells of the seminiferous tubules and to a lesser extent in cells at a peritubular and interstitial location. Present results demonstrate that in the chick embryo, FSH stimulates the proliferation of ovarian surface epithelium, oogonia in the cortex, and somatic cells of the medullary cords of the chick embryo ovary. In the chick embryo testis, FSH stimulates cell proliferation in seminiferous tubules and peritubular cells.

Animals↗

PubMed1993

Effect of host lineage on the virulence of Campylobacter jejuni/coli in the chick embryo model.

The chorioallantoic membrane (CAM) inoculated chick embryo model was used to study the effect of host lineage on the virulence of Campylobacter jejuni and Campylobacter coli. LD50 values were used to compare the susceptibilities of chick embryos from eight inbred chicken lines to infection by four strains of C. jejuni and one strain of C. coli. Differences in susceptibility were found between inbred chicken lines. These were shown not to be due to maternal antibody status, nor transfer of antibody to the developing embryo. Susceptibility to infection was also found to vary according to the Campylobacter strain used. These results indicate that both the bacterial strain and host lineage of the chicken line used affect resistance to infection in the CAM inoculated chick embryo model.

Allantois↗

PubMed1984

Selection for experimental metastatic ability of heterologous tumor cells in the chick embryo after DNA-mediated transfer.

The chick embryo is an immune-deficient host able to support growth of a wide variety of transformed cells. Since growth of normal cells is not observed, this system appears to be generally useful for investigating malignant properties of different cells. Recently, we developed a sensitive assay to quantitate and select for rodent cells able to survive and grow in embryonic chick organs following i.v. injection (Cancer Res., 42: 4018-4025, 1982). We envisage this assay as a model system for studying aspects of the metastatic process. We have used DNAs from murine and human melanoma cell lines (which grow well in chick embryos after i.v. injection) to transfect murine LTA cells (which do not grow in chicks after i.v. injection). From the transfected LTA cells, we were able to isolate clones which grow well in the chick after i.v. injection. Such clones were not observed in untransfected LTA cells or with LTA cells transfected with LTA DNA. These experiments clearly demonstrate the feasibility of using the chick embryo as a host system to study genes involved in growth control alteration of the sort seen in malignant transformation.

Animals↗

PubMed1981

Brain extracts that promote the proliferation of neuroblasts from chick embryo in culture.

The effects of brain and meningeal extracts from chick embryos on the proliferation of cultured neuroblasts from chick embryo cerebral hemispheres were studied. Morphological observations, counts of the cultured neurons, determination of DNA and protein contents as well as [3H]thymidine incorporation measurements were made to evaluate the proliferative activity of the neuroblasts. We demonstrated a stimulatory effect of brain extract from 8-day-old embryos on the proliferative activity of neuroblasts from chick embryos younger than 7 days. Brain extracts from older chick embryos and meningeal extract possess less stimulatory effect.

Animals↗

PubMed1995

In vitro survival and multiplication of chicken myeloblasts promoted for several weeks by chick embryo extract.

Growth of hemopoietic cells from chick embryonic aorta, spleen, and bone marrow was obtained in a serum-free culture medium containing 10-d-old chick embryo extract. When cells were cultured in semi-solid medium (plasma clot), they proliferated and differentiated to generate colonies committed to the granuloid or erythroid lineage. Mixed colonies composed either of granulocytes and macrophages or granulocytes and erythroblasts were also obtained. In addition, two different types of colonies composed of immature cells (blast cells) could be distinguished by the size of the cells. These colonies were composed of larger cells originating from the more immature progenitors, because they developed after a longer incubation period. Growth of bone marrow cells up to 3 wk in liquid culture was also obtained in the serum-free culture supplemented with chick embryo extract. These cells retained a very immature phenotype and the ability to differentiate when reseeded in an appropriate medium. These results indicate for the first time that chick embryo extracts contain hematopoietic growth factors that are active in differentiation and proliferation of chick hematopoietic cells.

Animals↗

PubMed1993

Raphe of the posterior neural tube in the chick embryo: its closure and reopening as studied in living embryos with a high definition light microscope.

Chick embryos cultured on a curved substratum show a transient enlargement of the posterior neuropore (PN), mimicking the temporary delay of PN closure as seen in the curly tail (ct) mouse mutant (van Straaten et al. [1993] Development 117:1163-1172). In the present study the PN enlargement in the chick embryo was investigated further with a high definition light microscope (HDmic), allowing high resolution viewing of living embryos in vitro. The temporary PN enlargement appeared due to considerable reopening of the raphe of the posterior neural tube, which was followed by reclosure after several hours. The raphe was subsequently studied in detail. It appeared very irregular, with small zones of apposed, open and fused neural folds. During closure, these raphe features shifted posteriorly. A distinct fusion sequence between surface epithelium and neuroepithelium was not seen. During experimental reopening of the raphe in vitro, small bridges temporarily arose, broke and disappeared quickly; they likely represented the first adhesion sites between the neural folds. More prominent adhesion sites partly detached, resulting in bridging filopodia-like connections; they probably represented the first anteroposterior locations of neural fold fusion. Our observations in the living chick embryo in vitro thus show that the caudal neural tube has an irregular raphe with few adhesion sites, which can be readily reopened. As a result of the irregularity, the PN does not close zipper-like, but button-like by forming multiple closure sites.

Animals↗

PubMed1987

Analysis of glucose levels during glucocorticoid-induced cataract formation in chick embryos.

When 15-day-old developing chick embryos were administered hydrocortisone hemisuccinate sodium (HC; 0.25 mumol/egg), the content of glucose in the lens markedly increased from around 6 hr, and reached about 25-30-fold above the matched control at 24-48 hr. Thereafter, the glucose level declined and returned to the control level by 100 hr. The profile of lenticular glucose levels was similar to that of the appearance and disappearance of lens opacification. Prednisolone, as well as HC, produced cataract and the elevation of glucose in the lenses. Cortexolone and cortisone, which have weak or negligible glucocorticoid activity in developing chick embryo, could neither produce cataract nor the elevation of glucose in the lenses. An attempt was made to find similarity between this glucocorticoid-induced cataract and sugar cataract known in mammals. In both control and HC-induced cataract (stage IV-V) obtained 48 hr after HC administration, sorbitol, fructose, and glycosylation of protein could not be detected. Dehydration was observed in HC-induced cataractous lens. These data demonstrate that the glycosylation of lenticular protein and the accumulation of polyol were not involved in glucocorticoid-induced cataract formation in developing chick embryos. These results suggest a relationship between the elevation of glucose and cataract formation. However, when cataract formation was blocked by ascorbic acid treatment, the glucose level remained high. Therefore, any relationship between glucose level and cataract may be complex or indirect.

Animals↗

PubMed1987

Estradiol-17 beta-induced morphometric changes in chick embryo femurs.

The influence of exogenous estradiol-17 beta (E2) on chick embryo femur morphology was assessed. Fertile chicken eggs were air cell injected with 18.75, 37.5, or 75 micrograms E2/.1 ml distilled water: ethanol (7:3, v/v) on Days 10, 12, and 14 of incubation. Controls received vehicle only (.1 ml) on the same days. On Day 16 of incubation, right femurs were excised, and midshaft cross sections were examined by light microscopy. Structural differences were quantified using a computerized histomorphometric technique. Injection of E2 produced significant (P less than .01) dose-dependent elevations in mean femur total osseous tissue area, bone matrix area, percent of matrix surfaces covered by osteoblasts, and percent of matrix area occupied by osteocytes when compared with controls. Estradiol was ineffective in inducing medullary bone formation in chick embryo femurs. We conclude that E2 is involved in bone matrix formation processes in chick embryos. The lack of medullary bone formation upon E2 treatment in chick embryos is perhaps an indication that, as in growing (immature) birds, it is likely that endogenous testosterone levels in Day 16 chick embryos are insufficient to support medullary bone growth.

Animals↗

PubMed2003

Acutely altered hemodynamics following venous obstruction in the early chick embryo.

In the venous clip model specific cardiac malformations are induced in the chick embryo by obstructing the right lateral vitelline vein with a microclip. Clipping alters venous return and intracardiac laminar blood flow patterns, with secondary effects on the mechanical load of the embryonic myocardium. We investigated the instantaneous effects of clipping the right lateral vitelline vein on hemodynamics in the stage-17 chick embryo. 32 chick embryos HH 17 were subdivided into venous clipped (N=16) and matched control embryos (N=16). Dorsal aortic blood flow velocity was measured with a 20 MHz pulsed Doppler meter. A time series of eight successive measurements per embryo was made starting just before clipping and ending 5h after clipping. Heart rate, peak systolic velocity, time-averaged velocity, peak blood flow, mean blood flow, peak acceleration and stroke volume were determined. All hemodynamic parameters decreased acutely after venous clipping and only three out of seven parameters (heart rate, time-averaged velocity and mean blood flow) showed a recovery to baseline values during the 5h study period. We conclude that the experimental alteration of venous return has major acute effects on hemodynamics in the chick embryo. These effects may be responsible for the observed cardiac malformations after clipping.

Animals↗

PubMed1991

Effects of hydrocortisone on the ultrastructure of the thymic cysts of the chick embryo.

Thymi from 80 19-day chick embryos that were injected with 2.5 mg of hydrocortisone on the 15th day of incubation were examined by light and electron microscopy. Six thymic tissue blocks from each embryo were evaluated. Hydrocortisone caused a marked depression of thymic volume due mainly to the depletion of lymphocytes. Cystic structures, consisting of intercellular and intracellular cysts and individual cystic cells, were more numerous per unit area of medullary tissue in treated embryos than in the controls. In the treated group, the shape of cystic cells varied from squamous to columnar, and hypertrophied columnar cells were also evident. The luminal surface possessed well-developed microvilli with membrane invaginations at their bases. The terminal web was prominent and the lateral plasma membranes were highly interdigitated. The rough and smooth-surface endoplasmic reticula and the Golgi complex of thymi from treated embryos were more developed than those in the controls. Mitochondria and vesicles were increased in number following hydrocortisone treatment. Cysts lined partially by cystic and endothelial-like and smooth muscle cells were encountered in the treated group. These structural modifications probably reflect responses to increased absorptive or transport function. The data suggest that hydrocortisone may alter the structure of cystic cells in chick embryos.

Animals↗

PubMed1996

Neural tube closure in the chick embryo is multiphasic.

Progression of neurulation in the chick embryo has not been well documented. To provide a detailed description, chick embryos were stained in ovo after the least manipulation possible to avoid distortion of the neural plate and folds. This allowed a morphological and morphometric description of the process of neurulation in relatively undisturbed chick embryos. Neurulation comprises several specific phases with distinct closure patterns and closure rates. The first closure event occurs, de novo, in the future mesencephalon at the 4-6 somite stage (sst 4-6). Soon afterwards, at sst 6-7, de novo closure is seen at the rhombocervical level in the form of multisite contacts of the neural folds. These contacts occur in register with the somites, suggesting that the somites may play a role in forcing elevation and apposition of the neural folds. The mesencephalic] and rhombocervical closure events define an intervening rhombencephalic neuropore, which is present for a brief period before it closes. The remaining pear-shaped posterior neuropore (PNP) narrows and displaces caudally, but its length remains constant in embryos with seven to ten somites, indicating that the caudal extension of the rhombocervical closure point and elongation of the caudal neural plate are keeping pace with each other. From sst 10 onward, the tapered cranial portion of the PNP closes fast in a zipper-like manner, and, subsequently, the wide caudal portion of the PNP closes rapidly as a result of the parallel alignment of its folds, with numerous button-like temporary contact points. A role for convergent extension in this closure event is suggested. The final remnant of the PNP closes at sst 18. Thus, as in mammals, chick neurulation involves multisite closure and probably results form several different development mechanisms at varying levels of the body axis.

Animals↗

PubMed1988

[Secretion of estradiol by the ovary of the hypophysectomized chick embryo].

Ovaries from control and hypophysectomized chick embryos were cultured in vitro, and oestradiol released into the culture medium was determined by radioimmunoassay. At all 4 stages investigated, i.e., 11, 13, 15 and 17 days, the ovary of hypophysectomized embryos secreted less oestradiol than the ovary of control embryos. However, per unit weight of ovary, oestradiol production was clearly less in hypophysectomized than in control embryos only at the stage of 11 days. It is concluded that the hypophysis plays a part in oestradiol secretion by the ovary in the 11-day-old chick embryo.

Animals↗

PubMed1988

Cholinergic neurons in cultures derived from three-, six- or eight-day-old chick embryo: a biochemical and immunocytochemical study.

Cultures were prepared by dissociating 3-day-old whole chick embryos, or 6- or 8-day-old chick embryo cerebral hemispheres. The dispersed cells were plated onto poly-L-lysine coated dishes in Dulbecco's modified Eagle's medium fortified with 10% fetal bovine calf serum. Immunocytochemistry, histochemistry and biochemistry were used to characterize the cholinergic neurons in these cultures. Double staining for acetylcholinesterase (AChE) and neurofilament revealed that a high percentage of neurons also contained AChE; fewer neurons though were positive for choline acetyltransferase (ChAT). The presence of AChE in non-cholinergic neurons was interpreted to be indicative of 'cholinoceptive' neurons in culture. The developmental profile for ChAT activity in cultures derived from 3-day-old whole chick embryos was previously described; we have reported that activity reached high levels by 7 days in culture. In this study we found that in cultures derived from 6-day-old chick embryos ChAT activity increased slowly up to 6 days in culture and rose markedly thereafter; in contrast, in cultures derived from 8-day-old chick embryos activity was low until day 9 and rose moderately thereafter. The differences in ChAT expression between cultures derived from chick embryos of different developmental stages may reflect a loss of plasticity of the cholinergic population with age.

Acetylcholinesterase↗

PubMedDate not supplied

[Comparative data on the propagation of cells from commercial common and leukemia-free chick embryos].

Certain differences were found in comparative studies of optimal conditions for preparation and propagation of cell cultures from common and leukemia-free chick embryos. The yield of cells per 1 g of tissue was regularly higher by 12-20% with leukemia-free chick embryos than with common chick embryos. The viability of the latter under conditions of roller cultivation was lower. Monolayer cultures of cells from leukemia-free chick embryos formed 1 day earlier than those from cells of common chick embryos. The optimal medium for growth of leukemia-free chick embryo cells was 0.5% lactalbumin hydrolysate, and for common chick embryo cells--Eagle's medium.

Animals↗

PubMed1987

Patterns of porphyrin accumulation in response to xenobiotics. Parallels between results in chick embryo and rodents.

Our objective was to determine whether patterns of porphyrin accumulation produced by chemicals in chick embryo hepatocyte culture would indicate which enzyme of heme biosynthesis was inhibited. The ferrochelatase-inhibitory potency and porphyrin patterns produced by DDC, TTMS, and their analogues were studied. The protoporphyrin:coproporphyrin ratio observed was found to correlate with ferrochelatase-inhibitory activity. The results obtained in chick embryo with TTMS and DDC parallel those found in rodents. Griseofulvin has been shown to lower ferrochelatase activity and to cause the accumulation of protoporphyrin in rodent liver. In chick embryo liver cell culture, however, coproporphyrin, uroporphyrin, and heptacarboxylic acid porphyrin accumulate and ferrochelatase activity is not lowered. Uroporphyrin, heptacarboxylic acid porphyrin, and coproporphyrin are the major porphyrins to accumulate in response to PAHs (for example, 3,3',4,4'-TCBP in chick embryo liver cell culture). This may be explained by inhibition of UROD, which has been observed in chick embryo and rodent liver. Some chemicals, such as phenobarbital and nifedipine, cause the accumulation of these porphyrins in chick embryo liver cell culture, and this is explained by inhibition of UROD. These chemicals have not been reported to interfere with heme biosynthesis in the intact chick embryo or rodents; possibly protective mechanisms that are not available in the cell culture system are operative in the intact animal. It was concluded that porphyrin patterns may serve as a guide to which enzyme of heme biosynthesis is inhibited in chick embryo liver cell culture. The results obtained in the culture system with certain chemicals, such as DDC and TTMS analogues and PAHs, correspond with results in rodents. In other cases, such as with griseofulvin, the results do not correspond.

5-Aminolevulinate Synthetase↗

PubMed1988

A low-molecular weight chick brain-derived growth factor is mitogenic for cultured astroglia from the chick embryo.

Immunohistochemically defined astrocytes from the 10-day chick embryo were stimulated to incorporate increased levels of [3H]thymidine when a low-molecular weight peptide growth factor, chick brain-derived growth factor (CBGF), was added to the cultures. Treatment of these GFAP-positive astrocytes with 10 ng/ml CBGF in medium supplemented with 1% fetal bovine serum resulted in a 3.5-4-fold increase in [3H]thymidine incorporation when compared to astrocytes cultured in defined medium supplemented with 1% serum alone. CBGF had no effect on the survival, proliferation or differentiation of a number of other cell types from the 10-day chick embryo brain, including neurons and meningeal fibroblasts. CBGF was also ineffective as a mitogen for chick embryo skeletal muscle myoblasts, primary mouse embryo fibroblasts and one murine teratocarcinoma-derived cell line (STO). We suggest that CBGF might act as a mitogenic signal for astroglia during central nervous system development and repair.

Animals↗

PubMed1997

An immunogenicity and efficacy study of purified chick embryo cell culture rabies vaccine manufactured in Japan.

Purified chick embryo cell rabies vaccine manufactured by the Chemo-Sero-Therapeutic Institute(Kaketsuken) at Kumamoto, Japan (Kaketsuken) was submitted to an immunogenicity and efficacy study. 52 severely rabies exposed patients were treated with the conventional five doses intramuscular WHO approved ('Essen') postexposure schedule. This included the administration of 40 IU kg-1 of equine rabies immune globulin on Day 0. A control group of equally severely exposed subjects were treated with human diploid cell rabies vaccine manufactured by the Swiss Serum and Vaccine Institute as well as human rabies immune globulin. There were no deaths in either group in the more than 2 years follow-up period. Subjects treated with the chick embryo vaccine showed greater suppression of the neutralizing antibody response by the equine rabies immune globulin than those given the human diploid cell vaccine and human rabies immune globulin. A group of 20 less severely rabies exposed patients who received only the chick embryo vaccine without immune globulin all had antibody titers greater than the WHO minimal acceptable level on Day 14, 30, 90 and 180. Fourteen subjects among the severely exposed vaccine and immune globulin study group were given vaccine boosters on Day 180 because of low antibody titers. It is concluded that chick embryo rabies vaccine manufactured by Kaketsuken is an immunogenic and effective rabies vaccine, but that the potency of future batches must be increased to provide a greater safety margin.

Animals↗