PAX6 haploinsufficiency causes cerebral malformation and olfactory dysfunction in humans.

PAX6 is widely expressed in the central nervous system. Heterozygous PAX6 mutations in human aniridia cause defects that would seem to be confined to the eye. Magnetic resonance imaging (MRI) and smell testing reveal the absence or hypoplasia of the anterior commissure and reduced olfaction in a large proportion of aniridia cases, which shows that PAX6 haploinsuffiency causes more widespread human neuro developmental anomalies.     

Topographical distribution of ATP in rat brain.

Studies on the distribution of ATP in microdissected segments of the rat brain indicate that the nucleotide is concentrated in gray matter, and especially in the thalamus, hippocampus, entorhinal cortex and sensorimotor cortex. These distribution studies in conjunction with previous neuropharmacological studies, support the concept that adenine nucleotides may function as intercellular mediators in various regions of the brain.     

Influence of local vascularity on hormone receptors in mammary gland

Procedures, such as teat removal (thelectomy) or teat duct ligation, which prevent removal of milk, lead to rapid involution of the lactating mammary gland; performed unilaterally they have been used previously to study the biochemistry of involution, enabling a comparison of normal and involuting glands in the same animal against the same systematic hormonal environment. Both the protein hormone prolactin and the steroid hormone oestrogen are of importance in the development and function of the mammary gland. In the present experiments, female Sprague-Dawley rats were unilaterally thelectomised and the binding to the mammary gland of prolactin and oestrogen was examined through pregnancy, lactation and weaning. There was an effect of thelectomy during lactation only, when levels of both receptors increased in the intact lactating gland but failed to rise in the thelectomised, involuting gland. Capillary closure is known to occur in the mammary glands of rats after 36-48 h of milk accumulation. The rate of delivery of hormones to the tissue will be drastically reduced and it is concluded that this, rather than systemic hormone levels, is of importance in controlling receptor levels.     

T-cell epitope of the autoantigen myelin basic protein that induces encephalomyelitis

Chronic relapsing paralysis and demyelination within the central nervous system (CNS), features associated with the human disease multiple sclerosis (MS), develop in mice after injection of murine T-cell clones specific for the autoantigen myelin basic protein (MBP). We examined the fine specificity of three independently derived encephalitogenic T-cell clones using synthetic polypeptides derived from portions of the N-terminal sequence of MBP. These clones appear functionally identical; they all respond to an epitope in the N-terminal nine amino acid residues in association with the same class II (I-A) molecules of the major histocompatibility complex (MHC). Both the N-terminal acetyl moiety and the first residue (Ala) are necessary for recognition. Only N-terminal MBP peptides recognized by these clones were found to cause encephalomyelitis (EAE) in vivo. These results show that the N-terminal MBP-specific T lymphocytes that mediate autoimmune encephalomyelitis are a small population with a limited repertoire; they all recognise the same combination of MHC and target.     

Linkage of an X-chromosome cleft palate gene

Many congenital malformations, such as cleft palate and neural tube defects, have a multifactorial origin involving both environmental and genetic factors. Conditions such as these may be exclusively monogenic, polygenic or environmental, but in most cases both genetic and environmental factors are involved. This study describes the sub-chromosomal localization of a single gene defect causing cleft palate and ankyloglossia (tongue-tied) in a large Icelandic family. This defect is a model for the analysis of other neural-crest malformations that show a more complex multifactorial inheritance pattern.     

Circadian rhythm in adrenal adenyl cyclase and corticosterone abolished by medial forebrain bundle transection in the rat

Zusammenfassung Nachweis, dass die Nebennierenrinde von Ratten nicht nur eine rhythmische Tagesschwankung in ihrem Gehalt an Corticosteron, sondern auch eine Schwankung im Gehalt an Adenyl-Cyclase aufweist. Diese Rhythmen können durch eine stereotaktisch ausgeführte Trennung des medianen Vorderhirnbündels, welches zum Hypothalamus führt, aufgehoben werden.

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This work was supported by research grants No. NS-05002 and No. HD-04581 from the National Institutes of Health, USPHS.     

Hormonal manipulation of carrageenin-induced pyresis in rats

Summary The intensity of the hyperthermic response in rats promoted by subplantar injection of 1 mg of carrageenin is directly related to the irritant properties of the type of carrageenin. The overall pyretic response is more dramatic in female rats than in male rats. Subtle changes in the time-course hyperthermic profiles are seen after hormonal modifications.This work was supported by NIH, MBS research grant No. RR08111.