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Biomedical subjects

J McCredie

Publications and source records attributed to J McCredie.

35 records · Page 2Linked to original sources
PubMed1978

Pathogenesis of congenital malformations. An hypothesis.

An hypothesis of neural crest injury, derived from a radiologic analysis of thalidomide deformities, is suggested as a possible pathogenetic mechanism of dysmelia and its associated visceral defects. Supportive evidence from a variety of sources is presented, and the hypothesis is shown to provide a unifying concept for a number of previously unrelated facts.

Abnormalities, Drug-Induced↗
PubMed1978

Congenital diaphragmatic hernia associated with homolateral upper limb malformation: a study of possible pathogenesis in four cases.

Four cases of congenital diaphragmatic hernia associated with homolateral upper limb reduction deformities are presented and are analyzed in terms of their pathogenesis. Diaphragm and upper limb are supplied by adjacent segments of cervical neural crest, and the sensitive period for upper limb formation occurs during early neural crest development. The evidence supports the possibility of cervical neural crest injury as the underlying pathogenesis.

Arm↗
PubMed1976

Neural crest defects. A neuroanatomic basis for classification of multiple malformations related to phocomelia.

Skeletal and internal structures are shown to be linked anatomically through segmental levels of innervation, or "neurotomes", and are related embryologically to the neural crest. Congenital abnormalities within the same or adjacent neurotomes would explain the distribution of defects in thalidomide embryopathy and morphologically similar multiple malformation syndromes. Classification of these "neural crest defects" on the basis of the segmental nerve supply is suggested.

Abnormalities, Multiple↗
PubMed1975

Segmental embryonic peripheral neuropathy.

Based on a new interpretation of the radiology, the author has proposed the hypothesis that reduction deformities of the limbs are of sensory neuropathic origin. This hypothesis is examined in terms of the segmental sensory innervation of the skeleton. The predicted effect of sclerotome subtraction is compared with the radiological malformations, and is found to support the hypothesis.

Abnormalities, Drug-Induced↗
PubMed1975

Congenital fusion of bones: radiology, embryology and pathogenesis.

Congenital fusion of bones of the limbs, a recurrent feature in thalidomide embryopathy, is discussed in terms of embryology. It is deduced that congenital fusion is neither a bone disease nor a cartilage disease, but a disorder of organisation of mesenchyme in the fifth week of life. It is suggested that the organising tissue is the sensory nerve. Hereditary influence is briefly mentioned.

Abnormalities, Drug-Induced↗
PubMed1975

The action of thalidomide on the peripheral nervous system of the embryo.

The mode of teratogenic action of thalidomide is unknown. A new radiological interpretation of thalidomide-induced limb malformations suggested that pathological changes should be sought in the sensory ganglia. Newborn rabbits with thalidomide-induced limb defects were examined histologically, and failure of maturation of dorsal root ganglion cells was demonstrated. This neuronal immaturity supports the radiological hypothesis of embryonic neuropathy, which is proposed as the underlying pathology of the limb deformities due to thalidomide.

Abnormalities, Drug-Induced↗
PubMedDate not supplied

Mechanism of the teratogenic effect of thalidomide.

The mechanism of the teratogenic effect of thalidomide is unknown. The hypothesis that this drug acts on the sensory nerves of the embryo was derived from radiological observations of two series of thalidomide-deformed children. Supplementary evidence was found in neurological, embryological and other literature, to support the hypothesis of embryonic neuropathy. The concept can be extended to include visceral as well as skeletal deformities. Evidence for and against the hypothesis is presented, and its application to a broad spectrum of congenital deformities provides an explanation of a number of previously unrelated facts. Areas for further research are suggested.

Abnormalities, Drug-Induced↗