Nervous System Involvement in Ankylosing Spondylitis

In a review of 45 patients with ankylosing spondylitis 10 had neurological symptoms and signs and three of them had two separate neuropathological disorders. The neurological profiles fell into five main categories—multiple sclerosis, the cauda equina syndrome, focal epilepsy, vertebrobasilar insufficiency, and peripheral nerve lesions. An association between ankylosing spondylitis and multiple sclerosis is suggested, possibly due to an immunological defect or to one being a complication of the other.     

The role of calcium in monoamine-induced depression of cerebral cortical neurones

The calcium antagonists, lanthanum, verapamil and manganese, have been shown to antagonize the depressant actions of ionto-phoretically applied monoamines (noradrenaline, 5-hydroxytryptamine, dopamine and histamine), but not of γ-aminobutyric acid, on cerebral cortical neurones. Cocaine and ethanol, which also affect membrane calcium fluxes, have a similar antagonistic action. These findings suggest that calcium ions are essential for, and perhaps mediate, the characteristic depressant actions of the monoamines on cerebral cortical neurones.     

River flow,zooplankton and dominant zooplanktivorous fish dynamics in a warm‐temperate South African estuary

The possible links between river flow, zooplankton abundance and the responses of zooplanktivorous fishes to physico‐chemical and food resource changes are assessed. To this end, the seasonal abundance, distribution and diet of the estuarine round‐herring Gilchristella aestuaria and Cape silverside Atherina breviceps were studied in the Kariega Estuary. Spatio‐temporal differences were determined for selected physico‐chemical variables, zooplankton abundance and zooplanktivorous fish abundance and distribution. Results indicated that, following a river flood event in winter (>30 m³ s^?1), altered physico‐chemical conditions occurred throughout the estuary and depressed zooplankton stocks. Abundance of G. aestuaria was highest in spring, with this species dominant in the upper and middle zones of the estuary, while A. breviceps was dominant in summer and preferred the middle and lower zones. The catch per unit of effort of both zooplanktivores also declined significantly following the flooding, thus suggesting that these fishes are reliant on zooplankton as a primary food source for healthy populations. Copepods dominated the stomach contents of both fish species, indicating a potential for strong interspecific competition for food, particularly in the middle reaches. Temporal differences were evident in dietary overlap between the two zooplanktivorous fish species and were correlated with river flow, zooplankton availability and fish distribution. The findings of this study emphasize the close trophic linkages between zooplankton and zooplanktivorous fishes under changing estuarine environmental conditions, particularly river flow and provide important baseline information for similar studies elsewhere in South Africa and the rest of the world.     

Mercaptopyridine-N-oxide, an NADH-fumarate reductase inhibitor, blocks Trypanosoma cruzi growth in culture and in infected myoblasts

The enzyme NADH-fumarate reductase is not found in mammalian cells but it is present in several parasitic protozoa including Trypanosoma cruzi, the parasite that causes Chagas' disease. This study shows that the drug 2-mercaptopyridine-N-oxide (MPNO) inhibits NADH-fumarate reductase purified from T. cruzi (ID50 = 35 microM). When added to intact cells, MPNO inhibited the growth of T. cruzi epimastigotes in culture (ID50 = 0.08 microM) as well as the infection of mammalian myoblasts by T. cruzi trypomastigotes (ID50 = 20 microM). At a concentration of 2.4 microM, MPNO also inhibited the growth of amastigotes (intracellular dividing forms) in cultured mammalian myoblasts. Supplementation of culture media with 5 mM succinate, the product of fumarate reductase, partially protected against the inhibition of the growth of epimastigotes by MPNO. Moreover, MPNO inhibited the accumulation of succinate in cultures of epimastigotes, as measured by high performance liquid chromatography. Although MPNO may have other intracellular targets in addition to fumarate reductase, these results support the hypothesis that compounds which inhibit the enzyme fumarate reductase may be potential chemotherapeutic agents against Chagas' disease.     

Density‐dependent increase in superpredation linked to food limitation in a recovering population of northern goshawks Accipiter gentilis

A better understanding of the mechanisms driving superpredation, the killing of smaller mesopredators by larger apex predators, is important because of the crucial role superpredation can play in structuring communities and because it often involves species of conservation concern. Here we document how the extent of superpredation has changed over time, and assessed the impact of such temporal variation on local mesopredator populations using 40 yr of dietary data collected from a recovering population of northern goshawks Accipiter gentilis, an archetypical avian superpredator. We then assessed which mechanisms were driving variation in superpredation, e.g. was it opportunistic, a response to food becoming limited (due to declines in preferred prey) or to reduce competition. Raptors comprised 8% of goshawk diet on average in years when goshawk abundance was high, which is higher than reported elsewhere. Additionally, there was a per capita increase in superpredation as goshawks recovered, with the proportion of goshawk diet comprising raptors increasing from 2 to 8% as the number of goshawk home‐ranges increased from ≤ 14 to ≥ 25. This increase in superpredation coincided with a population decline in the most commonly killed mesopredator, the Eurasian kestrel Falco tinnunculus, which may represent the reversal of the ‘mesopredator release’ process (i.e. mesopredator suppression) which occurred after goshawks and other large raptors declined or were extirpated. Food limitation was the most likely driver of superpredation in this system given: 1) the substantial decline of two main prey groups in goshawk diet, the increase in diet diversity and decrease in goshawk reproductive success are all consistent with the goshawk population becoming food‐limited; 2) it's unlikely to be purely opportunistic as the increase in superpredation did not reflect changes in the availability of mesopredator species; and 3) the majority of mesopredators killed by goshawks do not compete with goshawks for food or nest sites.     

A review of the influence of biogeography,riverine linkages,and marine connectivity on fish assemblages in evolving lagoons and lakes of coastal southern Africa

The Holocene evolution of eight South African coastal lakes and lagoons is examined and related to changes in fish composition over that period. Historical and current connectivity with riverine and marine environments are the primary determinants of present‐day fish assemblages in these systems. A small and remarkably consistent group of relict estuarine species have persisted in these coastal lakes and lagoons. The loss or reduction of connectivity with the sea has impacted on the diversity of marine fishes in all eight study systems, with no marine fishes occurring in those water bodies where connectivity has been completely broken (e.g. Sibaya, Groenvlei). In systems that have retained tenuous linkages with the sea (e.g., Verlorenvlei, Wilderness lakes), elements of the marine fish assemblage have persisted, especially the presence of facultative catadromous species. Freshwater fish diversity in coastal lakes and lagoons is a function of historical and present biogeography and salinity. From a freshwater biogeography perspective, the inflowing rivers of the four temperate systems reviewed here contain three or fewer native freshwater fishes, while the subtropical lakes that are fed by river systems contain up to 40 freshwater fish species. Thus, the significantly higher fish species diversity in subtropical versus temperate coastal lakes and lagoons comes as no surprise. Fish species diversity has been increased further in some systems (e.g., Groenvlei) by alien fish introductions. However, the impacts of fish introductions and translocations have not been studied in the coastal lakes and lagoons of South Africa. In these closed systems, it is probable that predation impacts on small estuarine fishes are significant. The recent alien fish introductions is an example of the growing threats to these systems during the Anthropocene, a period when human activities have had significant negative impacts and show potential to match the changes recorded during the entire Holocene.     

Mortuary rites of the South Fore and kuru

This paper is part of a wider study to explain the historical spread and changing epidemiological patterns of kuru by analysing factors that affect the transmission of kuru. Part of the study has been to look at the mortuary feasts that were the means of transmission of the kuru agent. This paper shows the complexity of Fore eschatology, and the variations and contradictions of human behaviour in relation to mortuary rites and the transmission of kuru. It also confirms that oral ingestion was the primary route of inoculation though some cases of parenteral inoculation may have occurred. The exclusion of alternative routes of transmission is of importance owing to the dietary exposure of the UK and other populations to bovine spongiform encephalopathy prions.