Microcephaly in familial holoprosencephaly

The holoprosencephaly sequence (HS) is characterized by abnormalities in forebrain cleavage and midface development. Familial holoprosencephaly has been reported in several families and there appears to be variable expression of the disorder in those who inherit the gene. Previous investigators have suggested hypotelorism and/or missing central incisors as mild manifestations of autosomal dominant HS. We evaluated a large kindred with three individuals with severe brain anomalies and 12 individuals with minor manifestations of the disorder. The most consistent sign in those mildly affected was microcephaly. We suggest that head circumference is an important part of the evaluation of the relatives of a patient with holoprosencephaly.     

Erosion of the foramen transversarium of the axis. Anatomical observations

Six hundred foramina transversaria (FT) of the axis vertebrae of 4 population groups were examined for the presence of erosion of the lateral articular mass. Of these, 127 (21%) and 72 (12%) presented with moderate and marked erosion, respectively. Evidence is presented incriminating the tortuosity of the vertebral artery as well as congenital factors in the etiology of the erosion of the FT. Attention is drawn to the possible correlation between angulation of the transverse process of the axis and erosion of the FT.     

Anatomical observations on somatic embryogenesis from scutellar tissues of immature zygotic embryos of Triticum aestivum

Somatic embryos were observed as early as six days after subculturing immature embryos of Triticum aestivum L. (cvs Froid-Centurk and Helge) in vitro on 2,4-dichloro-phenoxyacetate-containing nutrient media. Embryo formation followed three pathways, each involving one of the scutellum's three basic tissue systems: dermal, ground and vascular.
(1) Single epithelial layer cells divided tangentially to give pseudothallus-like structures which, through radial and oblique divisions, assumed polar, proembryoid symmetry.
(2) In actively dividing ground tissues, localized asymmetrical division in some cells resulted in proembryoids. When contiguous with each other, the proembryoids could be identified as a proembryonic mass.
(3) Oblique divisions in some cells of the scutellum's procambium resulted in daughter cells of unequal size, from the smaller of which the embryoid's root would eventually form.     

Anatomical and neurohistological observations on the tongue of the India goat, Capra aegagrus.

The anatomy and neurohistology of the tongue of the Indian goat, Capra aegagrus, have been described. The apex linguae is notched in the centre. The foramen caecum is found to be absent. The sublingua could not be traced. The filiform papillae are the most common and divided into three types: the simple, giant, and true filiform papillae. The true filiform papillae are the most developed of the three types. The foliate papillae are absent. There are 13--14 circumvallate papillae arranged in two rows in a V-shaped pattern. The fungiform papillae are large and could easily be seen with the naked eye. They are scattered over the entire dorsum, being in abundance at the tip. The tongue of the goat is richly innervated. On the dorsum, the lamina propria is innervated by thick nerve fibres. In the fungiform papillae quite a large number of nerve fibres could be seen. The circumvallate papillae are also abundantly provided with nerves. A few ganglion cells are found below the circumvallate papillae. Thick nerve fibres are seen across the numerous glands and their ducts. Muscle fibres and connective tissue are also richly innervated.     

Anatomical observations on the arcade of Frohse and other structures related to the deep radial nerve. Anatomical interpretation of deep radial nerve entrapment neuropathy

In a series of 120 elbow regions (66 male, 54 female) from embalmed human cadavers, the authors observed the course of the deep radial nerve and then related it to structures such as a) the deep surface of the initial part of the extensor carpi radialis brevis, which was found to be tendinous in 90% of the cases, b) the superior hiatus of the supinator muscle, which formed a fibrous arcade of Frohse in 61% of the cases, and the distance of its peak from the lateral condyle, which ranged from 4 to 6 cm, and c) the angle between the superficial oblique muscle fibres of the supinator and the long axis of the radius, which varies from 18 degrees to 38 degrees and crossed the nerve almost transversely. The above anatomical factors--and particularly the thickened fibrous arcade of Frohse--are all important for the deep radial entrapment neuropathy in predisposed individuals.     

Genetics of ventral forebrain development and holoprosencephaly

The disease holoprosencephaly is the basis of the most common structural anomaly of the developing forebrain in humans. Numerous teratogens when administered during early gastrulation, have been associated with this condition. Recent studies have characterized molecules expressed in the prechordal plate which are critical for normal brain formation. Perturbation of signaling pathways involving these molecules have been shown to cause holoprosencephaly in humans and other organisms.