This study confirms that PDT is a useful treatment and that selected superficial BCCs and SKs respond well to PDT. The PDT 1200 light source proved capable of treating multiple lesions amounting to a 'field change' and also lesions up to 10 cm in diameter within an acceptable treatment time. Thus far, PDT has failed to become established as a routine treatment for small premalignant and malignant skin lesions as it has not proved superior to simple cheaper conventional therapies such as cryotherapy, curettage and cautery, topical chemotherapy with 5-fluorouracil, or surgery. However, PDT has become established as a treatment for selected cases in some centres. This study suggests a role for PDT in the treatment of large premalignancies, superficial BCCs and field change where existing treatments may be problematic.

2. The extent of the vasodilation and vasoconstriction was found to be dependent on the stimulation frequency, but whereas vasodilation reached a maximum at 25 Hz, vasoconstriction occurred at lower frequencies and was maximum between 10 and 15 Hz.3. Atropine, in a dose much greater than that which inhibits nasal secretion, did not abolish the vasodilator responses evoked by Vidian nerve stimulation. This suggests that the Vidian nerve may convey atropine resistant fibres to the nasal vasculature.

1. A flow of watery nasal secretion can be induced in the anaesthetized cat either by electrical stimulation of the brain stem or by the simpler procedure of stimulating the cut peripheral end of the Vidian nerve. In both instances the rate of flow of secretion was dependent on the stimulation frequency. Because brain stem stimulation caused an increase in arterial blood pressure, nasal secretion was evoked in subsequent experiments by Vidian nerve stimulation. 2. The application of nicotine to the sphenopalatine ganglion shows that the secretory fibres in the Vidian nerve relay in this ganglion and reach the nasal mucosa by way of the posterior nasal nerve. 3. Inhibition by atropine of the secretion induced by Vidian nerve stimulation indicates that the secretory fibres are cholinergic. 4. It is suggested that the induction of nasal secretion by Vidian nerve stimulation may be useful in assessing the effects of drugs on this secretion.

No abstract

The lacrimal nerve, a branch of the trigeminal, is mainly a sensory nerve but it also conveys parasympathetic and probably sympathetic fibres to the lacrimal gland (Mutch, 1944). The role of these autonomic fibres in controlling lacrimal secretion is not clear. Stimulation of the lacrimal nerve in dogs was found by Tepliachine (1894) to cause an increase in lacrimal secretion. Botelho (1964) has shown that in cats and rabbits the secretory fibres are derived from the parasympathetic nervous system. In contrast, stimulation of the cervical sympathetic nerves produced variable effects on lacrimal secretion in man and animals (Wolferz, 1871;Reich, 1873;Schirmer, 1909;Duke-Elder, 1932; Whitwell, 1961; Botelho, 1964).The experiments described in this paper were undertaken to investigate the effects produced on lacrimal secretion in the cat by stimulation of the lacrimal nerve at different frequencies and to determine whether the secretory fibres were cholinergic. METHODSCats (2 to 4 kg of body weight) were anaesthetized with pentobarbitone sodium (35 mg/kg, intraperitoneally).Exposure of the lacrimal nerve presented a difficult problem; the most suitable approach consisted in removing the zygomatic arch after detaching the muscles from it. The nerve could then be located on the lateral aspect of the globe (Fig. 1). A ligature was tied round the lacrimal nerve as far centrally as possible and the nerve was cut proximal to the ligature. Further dissection in preliminary experiments had shown that a small branch of the lacrimal nerve supplied the lacrimal gland and that a larger branch appeared to innervate the superficial structures over the orbit. Since, however, section of the larger branch did not appear to modify the response of the lacrimal gland to nerve stimulation, it was left intact. Thus the lacrimal nerve could be exposed and stimulated at a site where it was readily accessible without dissection or exposure of the lacrimal gland.Rectangular wave stimuli of supramaximal intensity and 1.5 msec duration were applied to the peripheral end of the cut lacrimal nerve at frequencies ranging from 2 to 30 shocks/sec through bipolar platinum electrodes covered with liquid paraffin (B.P.). The nerve was stimulated for 5 min at a selected frequency and then allowed to rest for 10 min. This sequence was repeated for each of the frequencies used.The effects of nerve stimulation on lacrimal secretion were compared by a method similar to that described by Schirmer (1909). This consisted of placing into the superior fornix a suitably bent strip of Whatman No. 1 filter paper, 5 mm wide and 5 cm in length. To reduce loss by evaporation, the paper was enclosed in a plastic sheath. The strip was left in situ from the beginning of stimulation until immediately before the next stimulation period (a total of 15 min).