The Purkinje neuron: I. A Golgi study of its development in the mouse and in culture.

The development of the Purkinje neuron was studied in organotypic culture and compared to that occurring in the intact animal, using a modified Golgi-Cox method. The post-natal sequence of development in the intact animal occurred in five distinct stages beginning with (1) an immature state (0-3 days), (2) a stage of perisomatic dendritic processes (4-6 days), and then (3) a stage characterized by the presence of spines on the soma region (7-10 days). This stage of somatic spines has not been delineated previously in Golgi studies of the Purkinje cell during its development. There was no evidence that the lateral somatic processes resorb; rather they continue to grow and develop into dendritic branches. It is proposed that by a process of perikaryal translocation, the soma region becomes transferred "downward," resulting in an elongation of the primary, apical dendrite (stage 4, 11-14 days). Beyond 15 days (stage 5) the dendritic branches grow to the pial surface and the neuron has its full complement of secondary, tertiary, and spiny branches. In culture, the development parallels that occurring in the intact animal during the first 10 days (stages 1, 2, 3) despite the absence of extracerebellar afferents and the special conditions of the culture. However, there is an overall absence of lamination of the cortex, the Purkinje neurons do not align, and the developmental process is modified because of the failure of the process of perikaryal translocation in culture. The resultant mature neuron has an altered morphology characterized by the presence of several dendrites and spines attached to the soma, and also lacks the complete development of the smaller dendritic branches.

The Purkinje neuron: II. Electron microscopic analysis of the mature Purkinje neuron in organotypic culture.

Purkinje neurons of organotypic cultures were investigated electron microscopically following their analysis with the Golgi technique. The purpose of this study was to critically examine the issue of synaptic specificity in CNS cultures. The unique finding was the synaptic cluster, a terminal which engulfs many Purkinje spines. In the neuropil and on the major dendrites, this synaptic arrangement was interpreted to be a hypertrophic parallel fiber, representing a type of synaptic modulation. The terminals on the somatic spines are also in the form of clusters; some or all of these spines were thought to have developed to form synapses with the climbing fiber. In the absence of this afferent, the parallel fiber--a competing system--takes over the site. This represents a form of synaptic plasticity in these cultures. The inhibitory synaptic relationships were maintained on the soma and dendrites, but it was found that the basket synapses did not quantitatively encase the soma as is seen in the intact animal. Mossy-type terminals were found occasionally synapsing with Purkinje dendritic spines, as has been seen in agranular cerebellum in animals. These mossy terminals are presently thought to originate from the deep cerebellar nuclei within these cultures. Synaptic errors were rarely encountered. It is concluded that this preparation develops in accordance with established neurobiological principles, that the Purkinje neuron reaches a mature state in culture, and that this model has a sound anatomical basis for further experimental work.

Alclometasone dipropionate in psoriasis: a clinical study.

In a parallel group design, and using a 'blind evaluator' technique, alclometasone cream 0.05% and clobetasone butyrate cream 0.5% applied twice a day for 21 days were compared in thirty-one patients presenting with psoriasis. Erythema, induration and scaling were assessed at the start of treatment. Seven, 14 and 21 days later, effects of the two treatments were assessed and recorded together with the physician's global evaluation of overall improvement. Both drugs had similar beneficial effects on the clinical signs. No adverse experience was reported and the overall results indicate that alclometasone and clobetasone have comparable efficacy and safety.

A clinical study of quazepam in hospitalized patients with insomnia.

The efficacy of quazepam (Sch-16134) 15 mg capsules as a hypnotic has been compared with that of placebo in a 9-day study, using a parallel-group design. The physician's global evaluation numerically favoured quazepam 63% (nineteen of thirty) over placebo 50% (fifteen of thirty). Furthermore, it demonstrated greater improvement in Hypnotic Activity Index and Sleep Quality Index from baseline scores, and caused no adverse reactions.