Conspecific and Heterospecific Aboveground Herbivory Both Reduce Preference by a Belowground Herbivore.

Insect herbivores damage plants both above- and belowground, and interactions in each realm can influence the other via shared hosts. While effects of leaf damage on aboveground interactions have been well-documented, studies examining leaf damage effects on belowground interactions are limited, and mechanisms for these indirect interactions are poorly understood. We examined how leaf herbivory affects preference of root-feeding larvae [Acalymma vittatum F. (Coleoptera: Chrysomelidae)] in cucumber (Cucumis sativus L.). We manipulated leaf herbivory using conspecific adult A. vittatum and heterospecific larval Spodoptera frugiperda Smith (Lepidoptera: Noctuidae) herbivores in the greenhouse and the conspecific only in the field, allowing larvae to choose between roots of damaged and undamaged plants. We also examined whether leaf herbivory induced changes in defensive cucurbitacin C in leaves and roots. We hypothesized that induced changes in roots would deter larvae, and that effects would be stronger for damage by conspecifics than the unrelated caterpillar because the aboveground damage could be a cue to plants indicating future root damage by the same species. In both the greenhouse and field, plants with damaged leaves recruited significantly fewer larvae to their roots than undamaged plants. Effects of conspecific and heterospecific damage did not differ. Leaf damage did not induce changes in leaf or root cucurbitacin C, but did reduce root biomass. While past work has suggested that systemic induction by aboveground herbivory increases resistance in roots, our results suggest that decreased preference by belowground herbivores in this system may be because of reduced root growth.

Cisplatin-evoked induction of c-fos protein in the brainstem of the ferret: the effect of cervical vagotomy and the anti-emetic 5-HT3 receptor antagonist granisetron (BRL 43694).

We have monitored the expression of c-fos protein in the medulla oblongata of the ferret, using immunocytochemistry, to identify the brainstem pathways involved in the mediation of nausea and vomiting caused by the antineoplastic drug cisplatin. Cisplatin administration resulted in c-fos-like immunoreactivity (FLI) in the area postrema, the nucleus of the solitary tract, and in scattered cells within the ependymal lining of the fourth ventricle. Unilateral cervical vagotomy greatly reduced FLI in the ipsilateral nucleus of the solitary tract but did not significantly affect reactivity in the contralateral solitary tract nucleus or in the area postrema. Pretreatment of the animals with the 5-HT3 antagonist granisetron (BRL 43694) abolished the retching and vomiting caused by cisplatin and markedly reduced the cisplatin-evoked FLI in the nucleus of the solitary tract; treatment with this drug had no significant effect on cisplatin-evoked FLI in the area postrema. The results suggest that cisplatin induces c-fos gene expression in the nucleus of the solitary tract by an action involving vagal afferent pathways and also by a vagally independent, direct action on the area postrema. The anti-emetic 5-HT3 antagonist drug granisetron mimicked the effect of vagotomy on c-fos protein induction suggesting that it may act via 5-HT3 receptors known to be associated with vagal afferent terminals. The FLI seen in the area postrema was neither vagally dependent nor was it abolished by granisectron.(ABSTRACT TRUNCATED AT 250 WORDS)

Biologic behavior of ocular malignant melanoma and comparison with melanoma of the head and neck.

Ocular melanoma is the most common malignant tumor of the eye and accounts for 70 to 80 percent of all extracutaneous melanomas. Its biologic behavior differs from that of its cutaneous counterpart. To elucidate this, 62 patients with histologically proven melanoma of eye (58 uveal tract and 4 conjuntiva) at Roswell Park Memorial Institute from 1945 to 1977 were studied. The prominent contradistinctions from other head and neck melanomas were (1) a very high percentage of patients had either locally advanced or systemic disease at diagnosis, although the eye is the most sensitive organ; (2) regional lymph node involvement was absent even in the late stages of disease; (3) hematogenous spread involved single organs, most commonly the liver and the lung; (4) local recurrence was rare; (5) most recurrences occurred evenly in first 10 years after treatment; (6) regional resection, chemotherapy or both are advocated for distant metastases since they are confined to a single organ and are amenable to it; and (7) despite hematogenous spread and advanced disease at diagnosis, the overall prognosis of ocular melanoma is comparable to that of cutaneous melanoma.