Biomedical subjects

C A Matta

Publications and source records attributed to C A Matta.

12 recordsLinked to original sources

PubMed1992

Malformations of the eye in the exencephalic tail-short mice during its development.

Exencephalic tail-short (Ts/+) embryos were obtained from mating normal mice of Patch strain with Ts/+ mice from Babl/c strain. The most common eye malformations in the exencephalic embryos were exophthalmy, microphthalmy, eye ball irregularity and corneal opacity. Squint eye and unilateral anophthalmy occurred at a lower frequency. The eye abnormalities were recognized histologically by 11-days of gestation. The retina was retarded in development. Lens fibres were swollen and some of them appeared degenerated. Lens epithelium was protruded anteriorly, detached from the underlying lens and joined the corneal endothelium. The lens remained in close contact to the ectodermal layer, forming a thick lens stalk. At the 16-day stage, the corneal epithelium became irregular in thickness and the corneal stroma was discontinuous, having disarranged collagenous fibrils. In a few embryos the corneal endothelium was absent. In the squint-eyed embryo, the cornea bulged through the opened eyelids, while in an anophthalmic embryo it was thick and underdeveloped. Generally, the upper and lower eyelids of the exencephalic embryos were asymmetrical, and the lower lid appeared covered by a thick irregular peridermal layer.

Animals↗

PubMed1991

Cell lineage studies of the origin and differentiation of primary endoderm, using intraspecific chimaeras.

The origin of the primary endoderm was studied by combining experimentally eight-cell embryos and ICMs isolated by microsurgery from blastocysts homozygous for different alleles at the glucosephosphate isomerase (GPI-1) locus. The results confirm that the primary endoderm cells are derived from the ICM. The yolk sac splanchnopleure, which is composed of both extraembryonic endoderm and mesoderm, usually displayed the ICM GPI isoenzyme genotype. It must be concluded that the embryonic endoderm (visceral endoderm) and the parietal endoderm have a common origin and develop from the primitive ectoderm of the egg cylinder.

Animals↗

PubMed1991

Formation by aggregation of viable chimaeras between ICM and eight-cell mouse embryos with different genetic backgrounds.

The author studied the difference between immunosurgical and microsurgical isolation of inner cell masses (ICMs) from fully expanding blastocysts. The stage after which no further cell exchange between ICM and trophoblast can take place may involve the closure of certain gene pathways. The process of the aggregation of ICMs and eight-cell embryos with different genetic backgrounds was also studied. The results seem to lend strong support to the opinion that the microsurgical technique for isolating the differentiating ICM from the trophoblast is better than immunosurgery. The author also supports the view that the cells of the ICM become committed in the fully expanding blastocyst, while the cells of the eight-cell embryo are still labile and can differentiate to either ICM or trophoblast cells. Cell position during the aggregation process plays a role in cell determination and differentiation.

Animals↗

PubMed1990

Maternal treatment with teratogen causes congenital malformations in mouse embryos.

Heterozygotes for the tail-short (Ts) mutant gene in the Balb/c strain have minor skeletal defects and a short, kinky tail. If heterozygote Ts/+ mothers are mated with normal-tail +/+ males and are treated with teratogenic doses of trypan blue on the eighth day of pregnancy, the mutant F1 heterozygotes develop exencephaly, folded neural tube and spina bifida significantly more often than non-mutants. This is indicative of gene-teratogen interaction, with the Ts gene increasing the embryo's susceptibility to trypan blue-induced neural tube defects.

Abnormalities, Drug-Induced↗

PubMed1989

Histological studies of normal and mutant mouse embryo hearts (a glycogen content study).

Mutant tail-short (Ts/+) embryos are developmentally retarded compared with normal +/+ litter mates. The development of the heart of Ts/+ embryos is severely affected if the tail-short gene is transferred to a new genetic (50% A/Gr) background. The aim of the present study was to investigate the glycogen content of the sinus muscle, the cushion and the atrial and ventricular walls of the heart. In normal embryos the sinus muscle is well developed by the 15th day post coitum (d.p.c.) and is crowded with glycogen granules. In Ts/+ mutant embryos, on the other hand, the development of this muscle is retarded and it contains only a little, diffusely distributed glycogen. The atrial and ventricular walls of embryos with a normal heart are well trabeculated and contain a large quantity of glycogen granules, while in mutant embryos they are less well trabeculated and contain only a little glycogen in a diffuse of finely granular form.

Animals↗

PubMed1989

Embryonic development of the mouse, with reference to intrauterine position.

The degree of development of embryos in the same litter varied. In both the control and the experimental group the foetal weight curve followed a U-shaped course, with the lightest embryos in the intermediate position. A high incidence of split-face embryos was found in the lateral (ovarian) position in the uterus, while the highest frequency of exencephalic embryos occurred in the intermediate position.

Animals↗

PubMed1988