Search

Eighteen patients were diagnosed and treated for Stage IV-S neuroblastoma at The Hospital for Sick Children, Toronto between January 1971 and December 1988. All patients were 6 months of age or younger at diagnosis. Nine patients (50%) have remained disease free with a mean follow-up of 9.3 years. Of the seven patients under 6 weeks of age at presentation, four presented in the early neonatal period and died, three due to mechanical complications related to progressive disease, and one due to late recurrence. The remaining three patients under 6 weeks of age, two of whom had skin involvement at diagnosis, are alive and disease free. Six of the 11 patients over 6 weeks of age at presentation survived, combined modality therapy (CMT) being more effective than single modality treatment. N-myc was studied from tumor tissue at diagnosis in four patients and was amplified in three (25x, 25x, 100x), all of whom had late disease progression and died. The patient with a single gene copy has no evidence of disease 24 months following diagnosis. Our study confirms the heterogeneity described in this clinically defined group of patients. Because of it, management of Stage IV-S neuroblastoma cannot be uniform and until further development of a subclassification, or a reclassification based on molecular biologic markers is developed, pediatric oncologists will regularly be confronted with a decision whether or not to treat a newly presenting patient that fits into the clinical classification IV-S.

Widespread dieback of the introduced noxious weed Mimosa pigra was observed during the dry months in monsoonal northern Australia. Stems were girdled by reddish-brown lesions that generally originated from leaf axils. Botryodiplodia theobromae was consistently isolated from the lesions and was shown to cause the symptoms. It is suggested that the occurrence of dieback is linked with the establishment of a stem-boring moth introduced as a biological control agent for M. pigra.

The Mexican seed-feeding bruchids Acanthoscelides quadridentatus (Schaeffer) and A. puniceus Johnson were released at 32 sites, in 6 Mimosa pigra L. infestations in the Northern Territory between 13 April 1983 and 3 December 1985. Both species established but their impact on M. pigra populations has been negligible. Field collections over a 6 year period showed that 0.8% of M. pigra seeds were destroyed by the bruchids, and that 97.8% of bruchids recovered were A. puniceus.

The removal of seeds of the exotic shrub Mimosa pigra from the ground beneath a thicket of the plant and from the open floodplain surrounding the thicket was studied experimentally. Seeds placed beneath the canopy of the M. pigra thicket were taken predominantly by vertebrates (probably omnivorous rodents) while those on the open floodplain were taken predominantly by ants. After 14 days exposure with no barriers to seed removal, less than half of the seeds placed in either habitat had disappeared. Of the seeds that were removed, over 75% had disappeared from both habitats within 5 days. It is unlikely that post-dispersal seed predation appreciably inhibits the spread or maintenance of stands of this weed in tropical Australia.

Trioxys complanatus (Hymenoptera: Aphidiidae) was introduced into South Australia in August 1977 as a parasite of the spotted alfalfa aphid Therioaphis trifolii f. maculata. A mass rearing technique was devised whereby approximately 2 000 T. complanatus could be released at each of 14 fields, as primary release sites every week. A total of 39 primary release sites and 629 secondary release sites, inoculated from these with the help of farmers, were established. By the end of April 1978 T. complanatus was being recovered every week in samples from all 15 primary release sites and from most of the secondary release sites that had been visited. T. complanatus was capable of dispersing relatively long distances (at least 30 km) from release sites. By the end of November 1979 when the last releases were made, the parasite was considered permanently established throughout the region to the east of Spencer Gulf and in some areas to the west. T. complanatus displays all the qualities of an effective biological control agent.

Trioxys complanatus Quilis (Hymenoptera: Aphidiidae) was introduced into South Australia in August 1977 as a primary parasite of the spotted alfalfa aphid Therioaphis trifolii (Monell) f. maculata. The first hyperparasites of T. trifolii f. maculata were not recorded from field-collected T. complanatus pupae until April 1978, some 8 months after the initial releases of T. complanatus. Four species of aphid hyperparasites have been found attacking T. complanatus viz. Dendrocerus aphidum (Rondani), Pachyneuron aphidis Bouche, Phaenoglyphis villosa (Hartig) and Myiocnema sp.