Ultrastructural and histochemical studies of the rat iris: identified neuronal inputs and supportive glia.

A detailed ultrastructural description was made of the rat iris with special emphasis on nerve fibre populations and their supportive glial cells. The location and identity of different autonomic (sympathetic and parasympathetic) and sensory nerves was further studied by monoamine histofluorescence, acetylcholinesterase histochemistry, immunohistochemistry for substance P and neurofilament, and Linder's silver staining. Schwann cells were defined with immunohistochemical techniques using antiserum to glial fibrillary acidic protein. By correlation of these morphological techniques, the relative proportion of different neuronal inputs and their glial constituents in various parts of the rat iris could be determined. The sympathetic and parasympathetic unmyelinated fibres showed the well-known preferential localization in the posterior part, approaching the smooth muscle cells and chromatophores in the dilator muscle. Larger arterioles in the anterior loose stroma of the iris were in close proximity to sympathetic fibres as indicated by monoamine histofluorescence. Sensory trigeminal nerves were visualized both with Linder's silver staining and neurofilament immunohistochemistry. Large myelinated axon bundles in the anterior part of the iris were clearly seen, and thin unmyelinated fibres were scattered throughout the anterior and posterior parts. Unmyelinated substance P-containing fibres were scattered preferentially in the anterior part of the iris, without close association with blood vessels. Distribution of supportive cells, indicated by means of immunofluorescence with antiserum against glial fibrillary acidic protein, appeared largely similar to that of neurofilament-positive nerve fibres. In the sphincter muscle, cholinesterase-positive nerve fibres were densely packed and adrenergic fibres as well as sensory, neurofilament- and substance P-containing fibres were sparse but distributed throughout the muscle. Accompanying glial cells positive for glial fibrillary acidic protein were also found.

Adrenal medullary implants in the dopamine-denervated rat striatum. I. Acute catecholamine levels in grafts and host caudate as determined by HPLC-electrochemistry and fluorescence histochemical image analysis.

Rats with unilateral 6-hydroxydopamine-induced degeneration of the left nigrostriatal dopamine system were given intrastriatal implants of one cortex-free adrenal medulla divided into 4 pieces. Two pieces were placed in the center of the anterior part of the denervated caudate and two pieces in a more posterior position in lateral caudate. The distribution of catecholamines (CA) in grafts and host brain was studied 2, 100 and 400 min after grafting by HPLC-electrochemistry and Falck-Hillarp fluorescence histochemistry combined with computer-aided image analysis. Two minutes after implantation the chromaffin tissue grafts contained large amounts of adrenaline (A) and noradrenaline (NA) and small amounts of dopamine (DA). The chromaffin cells had a relatively normal fluorescence histochemical appearance. From the grafts, CA had spread into the surrounding host brain tissue where high levels of A and NA and low levels of DA were now found in the denervated host striatum. Fluorescence histochemistry and image analysis showed the CA to have spread 1-1.5 mm in all directions from the grafts. The CA concentrations decreased almost linearly with increasing distance from the grafts. At 100 min after implantation approximately a third of the chromaffin cells were still strongly fluorescent while the rest of the cells were very weakly fluorescent or non-fluorescent. The amounts of A, NA and DA in the host brain had decreased considerably, while the size of the fluorescent halo around the grafts had not diminished. At 400 min after grafting, only scattered cells in the chromaffin implants were strongly fluorescent and the surrounding host striatum contained low amounts of CA. It is concluded that intrastriatal adrenal medullary implants acutely release or leak large amounts of CA into surrounding host brain tissue. Taken together with results from the accompanying paper these data show that the grafts can maintain CA levels in host striatum high enough to elicit strong rotational responses during approximately 200 min.

Estramustine versus conventional estrogenic hormones in the initial treatment of highly or moderately differentiated prostatic carcinoma. A randomized study.

In a prospective randomized multicenter trial patients with highly or moderately differentiated prostatic carcinoma, previously untreated, were allotted either to oral Estramustine phosphate or to intramuscular polyestradiol phosphate plus oral ethinyl estradiol. As regards frequency and duration of tumour remission there was no statistical difference between the two groups. Nor did they differ significantly with respect to adverse reactions. This is an interim report and will be followed later on by a final evaluation.