Lethal temperatures of ammocoetes of the Southern Hemisphere lamprey,Geotria australis Gray

Synopsis The resistance time of ammocoetes ofGeotria australis was related to the time of emergence from the substrate. The incipient lethal temperatures of animals acclimated at 5, 15 and 25° C were 27.3, 27.5 and 28.2° C respectively, the ultimate incipient lethal being 28.3° C. This value, which is similar to that of Northern Hemisphere lampreys such asLampetra planeri, almost certainly accounts for the restriction of this species to the southernmost rivers in Western Australia.     

Changes in the amount of nonhaem iron in the plasma, whole body, and selected organs during the postlarval life of the lamprey Geotria australis

The concentration of plasma nonhaem iron and the concentration and weight of all nonhaem iron in the whole body and selected organs, together with its partitioning into ferritin and haemosiderin iron, have been measured during the metamorphosis and upstream spawning migration of the Southern Hemisphere lamprey Geotria australis. Some nonhaem iron was lost from the animal during metamorphosis. However, the concentration and weight of nonhaem iron in the liver rose sharply at this time, following its release from important storage sites in adipose tissue and the degradation of larval haemoglobins. The nephric fold of larval and metamorphosing stages contained over 40% of all nonhaem iron in the body at the commencement of metamorphosis. This was predominantly in the form of haemosiderin. While the rise in liver iron during the transition from larva to adult primarily reflected an increase in the weight of ferritin iron, the amount of iron stored as haemosiderin rose conspicuously towards the end of metamorphosis. The rise in ferritin iron in the liver was accompanied by a decrease in ferritin iron in the plasma, which implies that changes in the liver during metamorphosis result in a greater filtering of circulating ferritin. Such a process would account for the very much lower plasma nonhaem iron concentrations which characterise later adult stages. The weight of nonhaem iron increased markedly in the liver and adult opisthonephros and in the whole animal during the nontrophic upstream spawning migration. This was primarily due to a marked rise in ferritin which in turn could be related to the degradation of adult haemoglobins.(ABSTRACT TRUNCATED AT 250 WORDS)     

Cellular changes during the infusion of high dose intravenous immunoglobulin

With the ever widening group of autoimmune conditions that are beneficially affected by infusions of high dose immunoglobulin the possible mechanisms of action of such therapy appear increasingly complex. Fc mediated blockade of the mononuclear phagocyte system is an acknowledged early effect. This is, however, accompanied by a decrease of neutrophil counts which suggests that IgG binding to the neutrophil may be a mechanism of action. The decrease of neutrophil counts is transient but in immune thrombocytopenia is inversely proportional to the platelet response observed. In parallel to the effect on the neutrophil there are changes in the lymphocyte subsets with reversal of the T helper/suppressor ratio and alterations in the individual cellular constituents of each subset that correlate with the clinical response. The observed changes in B cell numbers and function suggest that T dependent and independent antibody production is effected by intravenous immunoglobulin. It is increasingly clear that in ITP at least the clinical response to IV IgG is a summation of several cellular events and their balance reflects the ultimate outcome. It may eventually be possible to use these observations to predict the likely outcome in the individual patient of this mode of therapy.