Characteristics of the compensatory renal growth of the remnant embryonic chick kidneys

Growth of the remnant embryonic kidney (the mesonephros), as expressed by wet weight, was more rapid in the chick embryos with experimentally induced unilateral renal agenesis compared to controls. The difference was significant between embryonic days 8-12, when the doubled weights of remnant kidneys were increased compared with the weights of paired control kidneys. The excessive growth of the mesonephros ceased on day 14, when the normal physiological regression of the embryonic kidney begins. In the definitive kidney, the metanephros, no significant differences in weights of the control vs. remnant metanephros were found on days 10-14. The characteristics of increased mesonephric growth were evaluated by determination of DNA/protein ratios in homogenates of the kidneys. Significant cellular hypertrophy was found in both the mesonephros and metanephros of the embryos with URA on day 10. Additionally, a non-significant cellular hyperplasia was also revealed in the remnant mesonephros on day 8. This gives evidence that the growth stimuli to the mesonephroi were probably strongest between days 8-10 and that they manifested in the remnant mesonephros only.     

Development of spontaneous motility in chick embryos. Sensitivity to aminergic transmitters.

The consequences of systemic administration of aminergic transmitters (n-adrenaline 16 microgram/kg egg weight; serotonin 2.5 and 5 mg/kg e.w.; dopamine 2.5 and 5 mg/kg e.w.) for the spontaneous motility and heart rate of 11- to 19-day chick embryos were studied intack eggs. The following results were characteristic for all three transmitters: a) when administered to 11- and 13-day embryos their effect was non-significant; the first signs of activity did not appear until the 15th day of incubation. The effect on 17- and 19-day embryos was stronger. b) After the 15th day of incubation, all these transmitters had a predominantly inhibitory effect on spontaneous motility; in 17- and 19-day embryos this acquired a periodic character. c) The changes in spontaneous motility did not correlate significantly in any way with the relatively small heart rate changes. It is concluded from the results that aminergic mechanisms begin to participate in regulation of the spontaneous motility of chick embryos from the 15th day of incubation, and not before.     

Interaction of beta-carboline with chick embryo spontaneous motility.

The effect of beta-carboline (beta-CCE) on spontaneous motility and its development was studied in chick embryos between the 11th and 19th day of incubation. 1. Acutely administered beta-CCE (7.5 mg/kg e.w.) already induced significant activation of motility in 11-day-old embryos. From the 17th day of incubation activation acquired a paroxysmal character. 2. In spinal embryos (decapitated on the second day of incubation) there was no such activating effect, demonstrating that it is associated with supraspinal components of the CNS. 3. In chronic administration from the fourth day of incubation (1.55 +/- 0.24 mg/kg e.w./24h), beta-CCE led to reduced development of spontaneous motility. The effect was concentrated in the period between the fourth and eighth day of incubation. The chronic administration of beta-CCE augmented the activating effect of metrazol and weakened GABA-inhibition of spontaneous motility. 4. On the basis of their findings, the authors express the hypothesis that the benzodiazepine beta-CCE-sensitive component of the complex GABA receptor evidently already functions from the beginning of the second half of incubation of chick embryos.     

Effects of hypoxia or hyperoxia on the lung of the chick embryo

Newborn mammals in chronic hypoxia or hyperoxia experience, respectively, an increase or decrease in lung weight:body weight ratios, possibly because of the mechanical effect on the lung accompanying the ventilatory response. Because the avian lung does not expand or contract with the breathing cycle, we asked whether or not qualitatively similar changes could be observed in the lung of chick embryos incubated in hypoxic or hyperoxic conditions. Hypoxic embryos (10% O2, days 14-18) were smaller than controls incubated in normoxia, with higher hematocrit values and larger lung weight:body weight ratios (both wet and dry). Both the total pulmonary DNA (reflecting the cellular component) and the DNA concentration were decreased in hypoxia. Hyperoxic embryos (50% O2, days 7-18 or days 14-18) had lower hematocrit values and smaller dry lung weight:body weight ratios than controls, with similar DNA concentrations. In general, the differences from controls were more apparent in those embryos hyperoxic from day 14 to 18 of incubation than from day 7 to 18. We conclude that changes in lung weights qualitatively similar to those occurring in the chronically hypoxic or hyperoxic newborn mammal can also be observed in the hypoxic or hyperoxic chick embryo, suggesting that they are not necessarily caused by changes in mechanical stretch on the lung.     

Action of ethanol on different skull and brain parameters in the chick embryo

Fifty microliters of ethanol diluted in 50 microl of distilled water were injected into the air chamber of chick eggs immediately before their incubation, and modifications in a series of parameters were recorded. The somatic weight of the ethanol-treated embryos was lower compared with control and vehicle-administered embryos during days 13, 15, 17, and 19 of incubation, but was the same on day 21. The brain weight was lower in the ethanol-treated embryos on all the days studied (days 13, 15, 17, 19, and 21 of incubation). Skull measurements showed that the transverse anteroposterior and sagittal diameters were significantly smaller in ethanol-treated embryos compared with control and vehicle-administered embryos on days 17, 19, and 21 of incubation.     

Consequences of chronic phenobarbital blockade of spontaneous motility in chick embryos for the development of central motor output activity

The consequences of the chronic continuous administration of Na+-phenobarbital in an average dose of 9.8 mg/kg e.w./24 h were studied in chick embryos. Administration was always started on the 4th day of incubation and lasted 4-12 days. Spontaneous motility was tested in 13- and 17-day-old embryos. The continuous, chronic administration of phenobarbital produced the following significant changes in the embryos' spontaneous motor activity and in the reactivity of their central motor output: 1) In 17-day-old embryos it reduced spontaneous motility in direct correlation to the time of administration. In 13-day-old embryos the effect was not yet significant. 2) It significantly inhibited strychnine, bicuculline and metrazol activation of motor output. 3) It raised the sensitivity to the acute administration of oxazepam (by 18-29.4%), but weakened the inhibitory effect of gamma-aminobutyric acid (by 17.6-33.2%). From the results of these observations it is deduced that spontaneous central motor output activity is not just a developmental epiphenomenon, but that it is an important prerequisite for normal development of the embryonic CNS.     

The stimulating effect of superlow doses of chronic gamma irradiation on the development of chick embryos

Dynamics of changes in mass of body and internal organs of irradiated chick embryos on days 4 to 21 of incubation is presented in the paper. The exposed embryos pass ahead of the controls by the development stages at early incubation times.     

Influence of ketamine on the spontaneous motility of chick embryos and its development.

The effects of acute and chronic application of ketamine on the resting spontaneous motility, its development and reactivity was studied in chick embryos of white Leghorns. 1. Acute application of ketamine (Narcamon) in a dose of 12.5 mg/kg e.w. partially depressed spontaneous motility as early as in 11-day old chick embryos. From day 15 of incubation ketamine very effectively blocked spontaneous motility. 2. Ketamine was fully ineffective in spinal preparations (decapitation on day 2 of incubation) of 11- and 13-day-old embryos. It was not until day 15 evoked that it depressed motility as in normal embryos. 3. Chronic continuous supply of ketamine (average dose 6.34 +/- 0.72 mg/kg e.w./24 h) from day 4 of incubation till day 8, 12, or 16 of incubation reduced the developmental decrease of spontaneous motility by 23.1-6.0% as compared to the controls. This effect was already observed after the first 4 days of chronic application of ketamine. 4. Chronic application of ketamine significantly diminished the strychnine activation and GABA-mediated depression of spontaneous motility. The depressive effect of the acute application of ketamine itself was hardly affected. The results have shown that ketamine interferes with the development of the endogenous rhythm of intrinsic activity and with the development of reactivity of the generator of embryonic spontaneous motility.     

Death of myocardiocytes and destruction of their structures during embryonic histogenesis

By means of light and electron microscopy, death of cardiomyocytes and their structures has been studied in the myocardium of chick (the 4th-20th days of incubation) and in rat (the 14th-20th days of embryogenesis) embryos. The same processes have been studied after a single and repeated injections of insulin and 5-fluorauracyl to the chick embryos (into the air chamber of the egg). In the myocardium of the chick and rat embryos atrophy of some muscle cells takes place as a demonstration of histogenetic (physiological) death characterized by changes in nucleo- and cytoplasm according to the "dark" type. Under the effect of 5-fluorauracyl the same type of cardiomyocyte death is observed; differences with the control are but quantitative ones. When the chick embryo is affected with cytotoxic concentrations of insulin, together with histogenetic death of the cardiomyocytes (the "dark" type) the death according to the "light" type also takes place. Under the effect of both insulin and 5-fluorauracyl the destructive processes in the cardiomyocytes are manifested greater than in the control. This is a morphological manifestation of certain disturbances in processes of physiological restoration at the cellular level.     

Influence of continuous electromagnetic fields on the stage, weight and stature of the chick embryo.

The influence of continuous electromagnetic fields (0, 181 or 361 Gs/cm2) on the development of chick embryo (n = 144) was studied. Several parameters were determined at days 5, 10 and 15 of incubation: stage (following Hamburger and Hamilton), vertex-coccyx length (size) and weight. At 5 days of incubation, all embryos showed a similar stage. However, at days 10 and 15, the embryos exposed to 181 Gs/cm2 showed a stage significantly superior to that of the others. There were no differences between the exposed embryos and the control ones with regard to weight and stature, except at 15 days when the embryos exposed to 361 Gs/cm2 showed greater weight and stature than those of the controls.     

Compatibility of chick embryo eye anlagen with the ectoderm of the early amphibian gastrula in vitro

Eye vesicles were isolated from the early chick embryos (stage 9+ after Hamburger and Hamilton, 1951) and combined with the Rana temporaria early gastrula ectoderm (EGE) in vitro. The tissues were jointly incubated in medium 199 diluted twice with deionized water at 22 +/- 1 degree for 7-8 days or the eye vesicles were removed from the EGE ectoderm within 16-18 h. At the joint long-term incubation of these tissues, a toxic effect of the chick embryonic tissues on the EGE cells was noted. In none of the experiments, the inducing effect of the eye vesicle on the EGE was found. Similar data were obtained when the EGE was jointly cultivated with the brain (stage 9-10) and retina (stage 15) of chick embryos. The brain of the chick embryos at stage 15 exerted a weak neuralizing effect on the EGE. In the control experiments, the eye vesicles explanted with the chick embryonic ectoderm remained viable till the end of cultivation but no lentoids formed in the ectoderm. The absence of lens-inducing effect at the joint cultivation of the chick embryonic eye vesicles with the EGE is considered as a result of disturbance of the synthesis or secretion of the corresponding agents rather than a sequence of the species "incompatibility" of the inductor and reacting tissue. Hence, the use of "xenogenic" tissue recombinants is not justified when analyzing the lens-inducing activity of the eye vesicles.     

Changes of creatine concentration during development of chick embryo

Changes of creatine concentration during development of chick embryo. Acta physiol. pol., 1985, 36 (3): 208-215. Investigations were carried out on embryos of Star Cross chicken after 6, 8, 10, 12, 14, 16, 18 and 20 days of incubation. It was found that the concentration of total creatine increased from 0.18 to 0.67 mg/g of embryo weight. The increase of creatine concentration at the time of development of the embryo was proportional to the increase in nitrogen concentration, and the share of creatine nitrogen in the pool of total nitrogen was about 1% throughout the whole period of embryonal development and during the first two days after hatching. The amount of creatine in fresh egg and in the yolk sac of the newly hatched chicken was about 1.5 mg. It was estimated that chick embryos during their development synthesized, on the average, 18 mg (6 mMol) of creatine. The course of changes in creatine concentration in the developing chick embryo is very similar to the course of changes in the rate of heat production.     

Immunoreactive insulin and insulin-like activity of the blood in ontogenesis of the hen]

Studies have been made on immunoreactive insulin (IRI) and insulin-like activity (ILA) in the blood serum of chick embryos (from the 10th day of incubation), chicks and adult hens up to 1 year old. It was shown that IRI content of embryonic blood is relatively low and remains approximately constant during incubation. During postnatal ontogenesis, the level of IRI increases, the increase being most significant at the 1st day after hatching and between the 2nd and the 5th months. With respect to IRI level, 5-month chicks are similar to adult hens. Being assayed by the method of isolated epididymal rat fat, ILA was not found in the blood serum of chick embryos. It was observed in all test samples only from the 30th day after hatching. It is suggested that at this period of postnatal life, some factors are formed in the blood which increase ILA without changes of the insulin content of the blood. After the 30th day, no evident shifts were observed in ILA, although it reached maximum in adult hens. By absolute values, ILA of the blood in chicks was several times higher than the corresponding levels of IRI.     

Immunohistochemical study of the appearance of somatotropic hormone in the adenohypophysis of chick embryos

The differentiation of somatotropocytes was studied in the Leghorn chick embryos during 11 to 18 days of incubation and in chickens during the first week of life using the immunohistochemical method of nonlabelled antibodies with PAP complex and antiserum against human somatotropic hormone (STH). Unlike in humans, the fixation of pituitaries in the Carnoy mixture is optimal for STH to be immunohistochemically estimated in the chickens and chick embryos. STH was found in adenohypophysis from 12-13 days of development. Besides predominant localization of somatotropocytes in the adenohypophysis caudal lobe, individual STH-positive cells are also present in the cephalic lobe of chickens and chick embryos. The results obtained suggest a relatively late appearance of STH during histotypical development of adenohypophysis in chick embryos.     

Emoxipin as an inhibitor of angiogenesis]

The effect of emoxypin on angiogenesis in rabbit cornea in aseptic inflammation induced by intracorneal implantation of a piece of quartz and on the development of the vessels of the chick embryo yolk sac was studied. 1% emoxypin pipetted thrice a day for 10-14 days inhibited corneal neovascularization and reduced the formation of new blood vessels. We observed an inhibitory effect on the development of vascular bed of the embryo yolk sac on incubation hour 64-72. The drug affected neither general growth of the embryos no the number of somites.     

Effect of pituitary grafting on ovarian oestradiol secretion in the hypophysectomized chick embryo.

Chick embryos were hypophysectomized by partial decapitation at the stage of 42 h of incubation and grafted with a hypophysis from a 12-days-old donor embryo on the chorio-allantoic membrane at 9 1/2 days. Two days later, their ovary was removed for organ culture and its oestradiol secretion rate was compared to that of the ovary of hypophysectomized, non grafted control embryos. The oestradiol secretion rate in the grafted embryos was almost twice that in the hypophysioprivic embryos and in the range of that in normal embryos. This result suggests that the hypophysis controls oestradiol secretion of the ovary in the 11 1/2-days-old chick embryo.     

Embryogenetic features of the serum protein composition of chicken blood

Protein composition of the blood serum in chick embryos of two breeds and in their hybrids has been investigated by polyacrylamide gel electrophoresis. Significant changes in the proportion of protein components of pre-albumin, albumin and post-albumin zones during prenatal development of chicks were observed. These changes are alleviated in hybrid embryos. The decrease in protein content of post-albumin zone, which contains foetoproteins, takes place to the end of incubation. This decrease is less significant in hybrid chicks as compared to that in the original hen breeds.     

Teratological studies with prostaglandin E2 in chick embryos

Prostaglandin E₂ (20–100 μg) was lethal to a relatively high percentage of chick embryos when administered at 48 hours incubation; no such effect was observed after 72 hours incubation. A relatively high incidence of abnormal embryos, which increased with the dose-levels of prostaglandin, was induced at both 48 and 72 hours incubation compared to the controls. However, this difference was statistically significant only in embryos treated with 100 μg prostaglandin at 48 hours incubation. The embryos showed no signs of growth retardation.     

Teratogenic effects of retinoic acid and dimethylsulfoxide on embryonic chick wing and somite

In order to document the stage(s) at which the embryonic chick wing bud is sensitive to vitamin A teratogenesis and the kinds of defects produced by vitamin A insult to the embryonic chick wing, 1-microgram doses of retinoic acid (1 microliter RA in 90% DMSO at a concentration of 1 microgram/microliter) were locally applied to the right wing bud of chick embryos at stages 17-23 (Hamburger and Hamilton: J. Morphol., 88:49-92, '51), and the resulting limb skeleton anatomy was observed at 10 days of incubation. Local application of RA at stages 17-20 resulted in distal wing skeleton defects. There were significantly more wing skeleton defects among embryos treated at these stages with RA solution than among solvent (DMSO)-treated control embryos and than among untreated control embryos. Wings of embryos treated with RA at stages 21-23 were always normal. Scapular and vertebral defects were seen at 10 days of incubation among embryos which had been treated prior to stage 21 with both the RA solution and the solvent control. Statistical analysis and histological data suggest that scapular and vertebral defects were caused by DMSO-induced damage to somites.     

Chick embryo culture using duck egg shell--first successful hatch

The suitability of duck egg shell (DES) for chick embryo culture was investigated. Chick embryos were transferred into DESs with all egg contents after 3 days of normal incubation and cultured. The vessels made of polyethylene cling film were used for shell-less control. Among 35 embryos cultured in DESs, 21 survived until 16 days of incubation (13 days after transfer) and finally 3 newly hatched chicks were obtained at 22 days of incubation. One of them died 4 days later, but remaining two became full-grown cocks showing normal body weight and production of fertile sperms. Among 37 embryos cultured in polyethylene vessels, none survived over the period of 19 days of incubation. It is suggested that DES culture system may be useful for the various experiments using chick embryos.