Nesfatin-1 and ghrelin levels in serum and saliva of epileptic patients: hormonal changes can have a major effect on seizure disorders

Nesfatin-1 and ghrelin are the two recently discovered peptide hormones involved in the control of appetite. Besides its main appetite-control function, ghrelin also has anticonvulsant effects, while nesfatin-1 causes depolarization in the paraventricular nucleus (PVN). The aims of this study, therefore, were to investigate: (i) whether there are differences in the concentrations of nesfatin-1 and ghrelin in saliva and serum samples between eplilepsy patients and normal controls and (ii) whether salivary glands produce nesfatin-1. The study included a total of 73 subjects: 8 patients who were newly diagnosed with primary generalized seizures and had recently started antiepileptic drug therapy; 21 who had primary generalized seizures and were continuing with established antiepileptic drug therapy; 24 who had partial seizures (simple: n = 12 or complex: n = 12) and were continuing with established antiepileptic drug therapy; and 20 controls. Salivary gland tissue samples were analyzed for nesfatin-1 expression by immunochemistry and ELISA. Saliva and serum ghrelin levels were measured by ELISA and RIA, and nesfatin-1 levels by ELISA. Nesfatin-1 immunoreactivity was detected in the striated and interlobular parts of the salivary glands and the ducts. The nesfatin-1 level in the brain was around 12 times higher than in the salivary gland. Before antiepileptic treatment, both saliva and serum nesfatin-1 levels were around 160-fold higher in patients who are newly diagnosed with primary generalized epilepsy (PGE) than in controls; these levels decreased with treatment but remained about 10 times higher than the control values. Saliva and serum nesfatin-1 levels from patients with PGE and partial epilepsies who were continuing antiepileptic drugs were also 10-fold higher than control values. Serum and saliva ghrelin levels were significantly (twofold) lower in epileptic patients before treatment than in controls; they recovered somewhat with treatment but remained below the control values. These results suggest that the low ghrelin and especially the dramatically elevated nesfatin-1 levels might contribute to the pathophyisology of epilepsy. Therefore, serum and saliva ghrelin and especially the remarkably increased nesfatin-1 might be candidate biomarkers for the diagnosis of epilepsy and for monitoring the response to anti-epileptic treatment.     

Plant Exclusion of a Herbivore; Crayfish Population Decline caused by an Invading Waterweed

The population of the crayfish Astacus astacus was recorded in Lake Steinsfjorden (southeast Norway) over the period 1979–1996 by studies of total catch effort (baited traps) and catch per unit effort over the season. Over the years 1979–1987, total population of exploitable crayfish (>9.5 cm) was 194,000 (±62,000 SD), and the catches were evenly distributed over the shallow areas. After 1987 there was a sudden decrease in population size, reaching a level of 92,000 (±22,000 SD) for the 10 years that followed. From 1977 onwards the Canadian pondweed Elodea canadensis invaded the lake and established dense covers over large parts of the shallow areas. The crayfish were gradually excluded from areas covered by Elodea, while the yield from remaining areas remained relatively constant. Direct observation by test-fishing and diving confirmed the virtual absence of crayfish within the Elodea stands. Dense stands may directly interfere with movement of adult crayfish, and also strong fluctuations in O₂ and pH were recorded within the stands, probably acting as a stress factor. Although anoxia was not observed in this survey, it may occur during years of massive dieback of Elodea. Thus, while crayfish are able to feed on Elodea, they are unable to control the rapid growth over large areas of this invader, and somewhat paradoxically the herbivore is spatially excluded by its potential resource.     

Aquatic ecosystem responses to fire and flood size in the Okavango Delta: observations from the seasonal floodplains

The frequency of fires in the Okavango Delta seasonal floodplains peaked at an intermediate frequency of flooding. Floodplains are commonly burnt every 3–5 years. This study showed fundamental changes in ecosystem properties due to burning. A burnt seasonal floodplain in the aquatic phase had oxygen levels well above saturation, 100–200%, while the levels in the un-burnt control site were below saturation and, at night, could decline to 10–40% saturation. The total phosphorous and total nitrogen concentrations were similar on both floodplains but considerably enriched relative to inflowing water, due to nutrient release from the flooded soil-sediment and animal droppings. Zooplankton biomass was very high in both systems although the abundance of fish fry was ten times higher on the un-burnt floodplain. In a low flood year the un-burnt floodplain water had high nutrient levels, primary production, methane emission, and subsequent uptake of methane in biota, as well as a high zooplankton biomass. The very high flood the following year showed the opposite with much lower production at all levels owing primarily to greater dilution of nutrients. The abundance of fish, however, was much higher during the high flood year. Macrophytes and litter provide direct shelter for fish fry but also promote low oxygen levels when decaying. Large flooded areas result in high fish production by removing obstacles related to congestion. This interplay between hydroperiod and fire may be crucial for the maintenance of high biological productivity both in the aquatic and terrestrial phases in a very nutrient poor wetland landscape. Understanding these interactions is crucial for optimal management.     

A primary screen of the bovine genome for quantitative trait loci affecting twinning rate

An autosomal genome scan for quantitative trait loci (QTL) affecting twinning rate was carried out in the Norwegian Cattle population. Suggestive QTL were detected on Chromosomes (Chr) 5, 7, 12, and 23. Among these, the QTL positions on both Chr 5 and Chr 23 are strongly supported by literature in the field. Our results also confirm previous mapping of a QTL for twinning to Chr 7, but definitely suggest a different location of the QTL on this chromosome. The most convincing QTL peak was observed for a region in the middle part of Chr 5 close to the insulin-like growth factor 1 (IGF1) gene. Since IGF1 plays an important role in the regulation of folliculogenesis, a mutation search was performed by sequencing more than 3.5 kb of the gene in actual families. The sequencing revealed three polymorphisms in noncoding regions of the gene that will be important in fine structure mapping and characterization of the QTL. Received: 14 December 1999 / Accepted: 25 May 2000     

Growth responses, P-uptake and loss of flagellae in Chlamydomonas reinhardtii exposed to UV-B

The flagellated, planktonic green alga Chlamydomonas reinhardtiiwas exposed to UV-B doses (peak intensity at 312 nm) from 0.6to 36 kJ m^-2. Flagellar status, uptake of ³³P and growth rateswere judged in both P-limited and P-saturated algae. A linearrelationship was found between loss or withdrawal of flagellaeand UV exposure. Even 10 min (0.6 kJ m^-2 exposure initiatedinactivation of flagellae and total loss as well as signs ofcell wall destruction were found at the highest doses Within72 h after irradiation, flagellar recovery had occurred in 34%of non-limited and 87% of P-limited cells. Uptake of P was apparentlyenhanced at low doses, but fell to almost zero at the higherdoses. In P-saturated cells, an initial high uptake was followedby a pronounced P leakage upon radiation. A similar patternwas found for growth rates, where notably P-limited cells gainedincreased growth at low doses, while growth was drasticallyreduced at 16 kJ m^-2. The data show that major functional parametersin this freshwater flagellate are affected by moderate dosesof UV-B, and that reduced P uptake is well correlated with inactivationof flagellae and growth inhibition.     

Factors determining the nutritive status and production of zooplankton in a humic lake

Zooplankton egg production and nutritional status as relatedto environmental factors were studied in a humic lake. Bothparameters exhibited a pronounced spring peak, a mid-summerdepression and a second, smaller autumnal peak. The overallmacrozooplankton community apparently suffered from severe foodlimitation, particularly with regard to food quality, duringthe study period. This limitation was confirmed with length/carbonregressions of well-fed and starved laboratory individuals ofDaphnia. Body carbon in the lake animals corresponded to thatof laboratory-raised, starved individuals. Regression analysisindicated that bacteria, particulate organic carbon and particulatenitrogen best explained changes in egg production, while algalbiomass was of negligible importance for all species. For Daphnia,size-specific carbon content (length/carbon regressions) andC/N ratios were computed for all sampling dates. a and b fromthe equation W=aL^b were positively correlated (P=0.001). a rangedover 1.17–4.44 and was positively correlated with size-specificcarbon content (P<0.001) and the C/N ratio (P=0.01). Whena mean time lag of 12 days was introduced, a was positivelycorrelated with egg production (P=0.04.6). b ranged over 2.05–3.54and was inversely correlated to the same parameters. Both simpleand multiple regression analysis confirmed that bacteria, particulateorganic carbon and particulate nitrogen gave the major positivecontribution to variance in size-specific C content, a and C/Nratio in Daphnia, whereas total zooplankton biomass was themain negative contributor to the same parameters.