FURTHER OBSERVATIONS ON JUVENILE AND ADULT HEDERA

Robbins , William J. (The New York Botanical Garden, New York, N. Y.) Further observations on juvenile and adult Hedera. Amer. Jour. Bot. 47(6) : 485–491. Illus. 1960.—Plants of arborescent Hedera helix sprayed with gibberellic acid produced juvenile shoots. Juvenile characters appeared in December to March from applications of gibberellic acid made from May to July. Gibberellic acid modified inflorescences toward a vegetative condition. Previous reports that seeds of arborescent Hedera helix produce juvenile plants were confirmed. Seedlings of a variant, Hedera helix ‘238th Street,‘ which has adult-shaped leaves on a vine type of growth produced vines with lobed leaves. Heavy pruning of arborescent Hedera helix caused the production of juvenile shoots.     

Catecholaminergic contributions to the neuronal machinery of the olfactory bulb: aftoradiographic, immunohistochemical and evoked feild potential studies

aftographic exeperiments on the localization of radiolabelednoradrenaline, dopamine and dopa, as well as immunohistochemicalstudies on hydroxylase-like activity, are summarized and comparedin both rat and turtle olfactory bulbs. Evoked field potentialstudies on effects of dopamine are also discussed. The histochemicalstudies suggest that dopaminergic periglomerular neurons arethe most significant cellular component of the catecholaminergicsystem in the olfactory bulb of both species. Scattered fluorescentcell group was also present in the internal plexiform layerand superficial granule cell layer of the turtle olfactory bulb.Other fibres, not related to intrinsic bulbar neuronal cellbodies, were also labeled, mostly in the granule cell layerbut also in the external plexiform layer. These might belongto a centrifugal catecholaminergic system from brain stem neurons.In the in vitro turtle olfactory bulb, dopamine and apomorphinedepressed the amplitude of field potentials evoked by a singlevolley in the olfactory nerve or lateral olfactory tract, andreduced the depression and latency of reponses when paired volleywere delivered. It is suggested that catecholaminergic systemsplay a key role in modulating mitral cell activity through actionsin both superficial (glomerular) and deep (granule) layers.This may involve direct actions, or other, non-catecholaminergicinterneurons.     

Altered thyroid hormone binding to plasma lipoproteins in the syndrome of resistance to thyroid hormones.

Lipoproteins, especially HDL, are carriers of a small fraction of the thyroid hormones in plasma and participate in the intracellular transport of T4. In previous work we showed that a brief period of hypothyroidism alters the hormone distribution among the lipoproteins, causing a decrease in VLDL and LDL binding despite a relative increase in VLDL and LDL cholesterol, an increase in HDL binding, and a reversal of T4 and T3 binding to the smallest HDL size subgroup. The present study of three patients with thyroid hormone resistance and largely compensated hypothyroidism showed thyroid hormone distribution that differed markedly from both normal and hypothyroid subjects. The most striking difference was a much lower binding of both T4 and T3 to HDL and a much higher binding to LDL. If confirmed in a larger group of patients, this might serve as a marker for thyroid hormone resistance.