Teratological changes in postembryos of Eratigena atrica obtained by the application of alternating temperatures on spider embryos

Spider embryonic development depends on several factors, including temperature. Under optimum thermal conditions embryogenesis proceeds undisturbed and embryo mortality is low. On the other hand, dramatic shifts in incubation temperature may cause a range of developmental defects in embryos. It has been confirmed in numerous laboratory experiments that abrupt temperature changes can be a powerful teratogenic factor. Changes in the external structure are frequently reflected in the internal anatomy, and above all, in the central nervous system. In the present teratological study, by exposing spider embryos to the temperatures of 14 °C and 32 °C, changed every 12 hours for the first 10 days of their development, we obtained 74 postembryos of Eratigena atrica with body deformities such as oligomely, heterosymely, schistomely, bicephaly, complex anomalies and others. We selected six spiders to describe and analyze their morphological changes. In one case, that of a spider affected by polymely (the presence of a supernumerary appendage) combined with heterosymely (the fusion of walking legs), we also focused on the structure of the central nervous system. The analysis indicated that this complex anomaly was accompanied by only one change in the central nervous system: the presence of a supernumerary neuropil. Since no fusion of walking leg neuropils was observed, it was concluded that, in this instance, there was no relationship between the fusion of legs and the structure of the central nervous system.

A Review on Holoprosencephaly Disease (CYCLOPIA): Risk Factors, Causes, Pathophysiology and Diagnosis with spotlight of various features reported in cases

Holoprosencephaly has a sever condition called Cylopia that is occur due to embryonic prosencephalon cleavage failure and contrast. Mostly cylopia form is holoprosencephaly, mid facial tissue is absent which causes the one eye on a single orbit. It is a sever deformity of median faciocerebal development. There are 1.05 cases in100,000 birth, still births of cyclopean. Abnormal nose above eyes or absence of nose, single eyes or half divided eyes in single orbit are features of cyclopia, where as reduced size of oral aperture or absence of mouth, absence of mandible with ears below chin. It is as etiologically heterogeneous condition, which can be caused by genetic mutation, chromosomal defect and teratogenic environmental factors. Environmental factors can be diabetic embryopathy, retinoic acid, several anecdotal suggestion of teratogenic factor for HPE, which includes salicylates and viruses. Some list of syndrome are also involved to cause cyclopia Like steinfeld syndrome, dysgnathia complex,Pseudotrisomy 13 syndrome and Smith–Lemli– Opitz syndrome. On other hand inborn abnormalities also cause cyclopia but its come under chromosomal syndrome. Anatomical detection can be done by brain MRI, whereas in prenetal diagnosis, sonography is more significant. Ultrasound also used early detection can be done and knowledge of sonographic finding soectrum leads to accuracy of prenatal diagnosis of cyclopia. After birth the chromosomal study helps to diagnose cyclopia along with postmortem biopsy.

A Case of Nonsyndromic Unilateral Cleft Hand with Central Polydactyly, Syndactyly, and Thumb Hypoplasia: Support for a Common Etiology

Experimental studies showed that central polydactyly, syndactyly, and cleft hand might appear when the same teratogenic factor acts on embryos at the same developmental stage. These observations and some clinical cases support the concept that a common etiologic mechanism is involved in the development of these malformations. We report a clinical case that demonstrates the association previously observed in experimental studies. Here, a patient with unilateral nonsyndromic cleft hand, central polydactyly, first web syndactyly, osseous syndactyly between the ring and long fingers, and minor thumb hypoplasia was presented.

Epimorphosis and repair processes of schistomelic pedipalps and walking appendages in Tegenaria atrica (Araneae, Agelenidae)

Experimental studies of regeneration and repair processes of schistomelic walking legs and pedipalps in the early postembryonal stages of Tegenaria atrica were carried out in two parts. In the first part changes in the structure of appendages were produced by exposing the developing embryos to alternating temperatures (14 and 32°C, changing every 12 hours) as teratogenic factor. In the second, principal, part of studies after amputating a given fragment of a larval schistomelic appendage the appearance, then the growth and development of the external regenerates were observed. The completion of epimorphosis of the pedipalps followed at nymph IV stage (after four post-larval moults) that of the walking appendages in most cases at nymph V stage (after five post-larval moults). In control spiders repair processes were noted, which proceeded at a rate comparable to regeneration processes.

MR Imaging of Congenital and Acquired Malformation of the Eye and Orbit

As for all the central nervous system (CNS) defects, the severity of eye malformations is related to the time a teratogenic factor occurs: the earlier the insult, the more serious the eye abnormalities are. Magnetic resonance imaging perfectly depicts most eye defects. Considering that several CNS malformations have been described to occur simultaneously in the case of eye abnormalities, MRI is considered the imaging modality of choice nowadays.

Teratogenic Relationship between Polydactyly, Syndactyly and Cleft Hand

Several investigators have suggested that polydactyly, syndactyly and cleft hand might have arisen from a common teratogenic mechanism. To confirm this hypothesis, 75 hands with these anomalies were analysed. Advanced cases with central polydactyly or osseous syndactyly in which the fusion area extends as far as the proximal phalanx and metacarpus are identical to typical cleft hand. The author has induced the same deformities using myleran in rat foetuses. The clinical features of these anomalies in rats were the same as those in clinical cases and the critical periods of these anomalies were also the same. The findings suggest that these hand anomalies may appear in human beings when the same teratogenic factor acts on the embryo at the same developmental period and that they should belong to the same teratogenic entity.