Filtrin is a novel member of nephrin-like proteins

NPHS1 encodes nephrin, the core protein of the interpodocyte slit diaphragm of the kidney glomerulus. NPHS1 is the causative gene for congenital nephrotic syndrome of the Finnish type (CNF) with massive, treatment resistant proteinuria. We report here the establishment of a novel nephrin-like gene, NLG1 encoding filtrin, a protein with substantial homology to human nephrin. Filtrin is a type I transmembrane protein consisting of 708 amino acids. Together with the recently cloned NEPH1, NLG1 establishes a new nephrin-like subgroup of genes belonging to the immunoglobulin superfamily of cell adhesion molecules. The RNA dot blot experiment revealed that the NLG1 mRNA expression is widely distributed but most prominently observed in the pancreas and lymph nodes. The expression of NLG1 mRNA in kidney glomeruli was verified with RT-PCR. Further immunoblotting studies with antifiltrin antibody showed a specific band at 107kDa in the human and rat glomeruli. In immunofluorescence microscopy specific staining of glomeruli but also proximal and distal parts of the nephron was seen in human kidney cortex. Due to its structural similarity and sequence homology as well as partially consistent expression pattern with nephrin we propose that filtrin belongs to a functionally important complex of proteins of the glomerular filtration barrier.     

Biogeography of helminth parasitism in Lemmus Link (Arvicolinae), with the description of Paranoplocephala fellmani n. sp. (Cestoda: Anoplocephalidae) from the Norwegian lemming L. lemmus (Linnaeus)

We describe the gastrointestinal helminth fauna of true lemmings (Lemmus spp., Arvicolinae) based on published and original material throughout the Holarctic range of these hosts. According to the existing data, the helminth fauna of true lemmings consists of three widespread and/or locally common taxa: Hymenolepis horrida (sensu lato) (Hymenolepididae), Anoplocephaloides lemmi (Anoplocephalidae) and Heligmosomoides spp. (Heligmosomidae). Despite the taxonomic boundaries and ancient phylogenetic splits in the hosts, there are no major faunistic differences for parasites within western (Siberian) L. sibiricus and L. bungei, and eastern (North American) L. trimucronatus throughout their distribution range. In contrast, the Norwegian lemming L. lemmus, which is a Fennoscandian endemic and closely related to the western populations of L. sibiricus, has only a single host-specific helminth, the cestode Paranoplocephala fellmani n. sp. (Anoplocephalidae). We describe the new species and show that it differs consistently from related species by its long and slender cirrus-sac. However, there are also a number of other significant differences, e.g., P. fellmani n. sp. and Andrya primordialis in Tamiasciurus hudsonicus (Sciuridae) evidently have a unique (sub)type of uterine development among Andrya/Paranoplocephala spp. Because P. fellmani n. sp. was also found to occur in Alaska (host L. trimucronatus), this species seems to follow the same biogeographical pattern as the other specialist helminths of Lemmus. We suggest alternative explanations for the absence of three major helminth taxa in the Norwegian lemming in Fennoscandia.     

Effects of ovariectomy and estrogen treatment on learning and hippocampal neurotransmitters in mice

This study examined the effects of long-term estrogen treatment (sc 17 beta-estradiol minipellets) on learning in C57BL/6J female and male mice using a position discrimination task in the T-maze and a win-stay task (1/8 arms baited) in the radial arm maze (RAM). In addition, hippocampal monoamines and ChAT activity were measured at the end of the study and correlated to task performance. Female sham-operated (gonadally intact) and ovariectomized (OVX) mice were treated with estrogen either for 7 or 40 days before the behavioral tests and intact male mice for 7 days before the behavioral tests. In sham-operated mice the 40-day estrogen treatment improved RAM performance and in OVX mice both the 7- and 40-day estrogen treatments improved the performance in both maze tasks. The estrogen treatment also improved RAM performance in males. The hippocampal ChAT, NA, 5-HIAA, and DOPAC levels were decreased in OVX mice. Furthermore, the effects of estrogen treatment on the levels of hippocampal 5-HT and its metabolite 5-HIAA were different in sham-operated than in OVX mice. We could find no correlation between cognitive measures and neurochemical variables. This study gives new information about the effects of estrogen on learning and hippocampal neurotransmitters in mice.     

Leptin,ghrelin, and energy metabolism of the spawning burbot (Lota lota,L.)

The aim of this study was to investigate the energy metabolism of the burbot (Lota lota, n=38) before, during, and after spawning, which represents the greatest annual metabolic demand for the species. A decrease in body mass, relative weight of the livers, and glycogen concentration of the livers was observed toward the end of spawning. The prespawning period was characterized by high rates of liver glycogenolysis and lipid mobilization. Also, plasma triiodothyronine and sex steroid levels were high before reproduction. During spawning, liver lipolysis was reduced and muscle glycogenolysis stimulated. The levels of triiodothyronine and sex steroids decreased. After reproduction, liver glycogenolysis was suppressed and the rate of gluconeogenesis increased. Thyroid hormone levels were elevated after spawning. Leptin protein and a ghrelin-immunoreactive peptide were detected in burbot plasma. Their concentrations were relatively low before and during reproduction but increased after spawning. The functions of leptin and the ghrelin-immunoreactive peptide in the physiology of the burbot are not consistent with the models of their function in mammals.     

Effects of gender,diet, exogenous melatonin and subchronic PCB exposure on plasma immunoglobulin G in mink

Effects of different fish-based diets (freshwater smelt, Baltic herring, marine herring/cod offal or their mixtures), gender, beta-glucan supplement, exogenous melatonin, and PCB exposure (Aroclor 1242((R)), 1 mg per animal per day in feed) on plasma immunoglobulin G (IgG) in the mink (Mustela vison) were studied. The aims of the study were to find out whether plasma IgG of the mink is affected by the subchronic PCB exposure, and whether biological, nutritional and hormonal effects are large enough to mask the possible IgG response. The concentration of IgG was determined using enzyme-linked immunosorbent assay (ELISA). Sexual dimorphism was detected, the males having higher levels of plasma IgG. In addition, melatonin tended to decrease IgG in females but not males. Diet also affected the humoral immune arm; the mixed-fish diets caused an unfavorable ratio of the oxidation products of lipids vs. vitamin E in liver, and resulted in low IgG concentration in plasma. In males fed Baltic herring, the beta-glucan supplement also lowered IgG levels. The PCBs failed to affect the plasma IgG of the smelt-fed female mink, and IgG concentration was not correlated with increased hepatic EROD activity or with the decreased total retinol in the liver of exposed mink. It is concluded that hormonal/seasonal and dietary factors affect the plasma IgG levels to such an extent that possible change in plasma IgG level due to PCBs in wild populations of mink is difficult to detect without a large amount of reference data.     

Effects of training on the exercise-induced changes in serum amino acids and hormones

The purpose of this study was to examine power-type athletes to determine changes in amino acid and hormone concentrations in circulating blood following 2 different high-intensity exercise sessions before and after the 5-week training period. Eleven competitive male sprinters and jumpers performed 2 different running exercise sessions: a short run session (SRS) of 3 x 4 x 60 m (intensity of 91-95%) with recoveries of 120 and 360 seconds, and a long run session (LRS) with 20-second intervals (intensity of 56-100%) with recoveries of 100 seconds to exhaustion. The concentrations of serum amino acids, hormones, and lactate were determined from the blood samples drawn after an overnight fast and 10 minutes before and after both SRS and LRS. The average blood lactate concentrations were 12.7 +/- 1.6 mmol;pdL(-1) and 16.6 +/- 1.4 mmol;pdL(-1) (p < 0.01) following SRS and LRS, respectively. The average total running time was longer (p < 0.001) following LRS (164 +/- 20 seconds) than following SRS (91 +/- 8 seconds). The fasting levels of all amino acids decreased (p = 0.024; 19.4%) after the 5-week period, whereas an increase (p = 0.007; 24.5%) was observed in the fasting concentration of testosterone (TE). The exercise sessions induced no changes in the total sum of all amino acids, but significant increases or decreases were observed in single amino acids. When the range of the relative concentration changes before and after the training period was compared, significant decreases were found in valine (p = 0.048), asparagine (p = 0.029), and taurine (p = 0.030) following SRS. There were significant increases in the absolute hormonal concentration changes following LRS with TE (p = 0.002; 30.4%), cortisol (COR; p = 0.006; 12.0%), and in the TE/COR ratio (p = 0.047; 21.0%) but not in the concentration of growth hormone (GH). The results of the study indicate that the speed and strength training period strongly decreases the fasting concentrations of amino acids in the power-trained athletes in a good anabolic state with the daily protein intake of 1.26 g;pdkg(-1) body weight. At the same time the intensive lactic exercise session induces strong decreases, especially in valine, asparagine, and taurine.     

Standardization and validation of the body weight adjustment regression equations in Olympic weightlifting

The problems in comparing the performances of Olympic weightlifters arise from the fact that the relationship between body weight and weightlifting results is not linear. In the present study, this relationship was examined by using a nonparametric curve fitting technique of robust locally weighted regression (LOWESS) on relatively large data sets of the weightlifting results made in top international competitions. Power function formulas were derived from the fitted LOWESS values to represent the relationship between the 2 variables in a way that directly compares the snatch, clean-and-jerk, and total weightlifting results of a given athlete with those of the world-class weightlifters (golden standards). A residual analysis of several other parametric models derived from the initial results showed that they all experience inconsistencies, yielding either underestimation or overestimation of certain body weights. In addition, the existing handicapping formulas commonly used in normalizing the performances of Olympic weightlifters did not yield satisfactory results when applied to the present data. It was concluded that the devised formulas may provide objective means for the evaluation of the performances of male weightlifters, regardless of their body weights, ages, or performance levels.     

Melatonin and the wintering strategy of the tundra vole,Microtus oeconomus

Short photoperiod induces physiological changes connected to the wintering of the tundra vole, Microtus oeconomus. The aim of the present study was to investigate the effects of continuous melatonin treatment on selected hormones and enzyme activities associated with energy metabolism in the species. Liver, kidney, and muscle glycogen concentrations and glycogen phosphorylase activities, as well as liver and kidney glucose-6-phosphatase and lipase esterase activities were determined. Plasma leptin, ghrelin, thyroxine, testosterone, cortisol, and melatonin concentrations were also measured. Exogenous melatonin stimulated gluconeogenesis, increased glycogen stores, and reduced fat mobilization in kidneys. Melatonin treatment also increased the food intake of the voles. This may have been mediated via elevated ghrelin levels of the melatonin-treated animals, as ghrelin is known to increase appetite of rodents. Winter metabolism of the species does not seem to require accumulation of fat or extra stores of liver or muscle glycogen. On the contrary, successful wintering of the tundra vole presumably depends on continuous food availability.     

Seasonal weight regulation of the raccoon dog (Nyctereutes procyonoides): interactions between melatonin,leptin, ghrelin,and growth hormone

The raccoon dog (Nyctereutes procyonoides, Canidae, Carnivora) is a middle-sized omnivore with excessive autumnal fattening and winter sleep. We studied seasonal weight regulation of the species by following the plasma leptin, ghrelin, and growth hormone (GH) levels of farm-bred raccoon dogs (n = 32) for 6 months. In August, half of the raccoon dogs received continuous-release melatonin implants, and in November, half of the animals of both the sham-operated and melatonin-treated groups were fasted for 2 months. In the autumn, the plasma leptin and GH levels were low, but the ghrelin levels were relatively high and correlated positively with energy intake. This represents the period of energy storage. Leptin and GH levels peaked simultaneously in late October, and melatonin advanced the peaks by 1 week. Thereafter, the levels rapidly declined, representing the transition period from autumnal anabolism to wintertime catabolism. In the winter, the leptin and GH levels rose to high levels, but the ghrelin-leptin ratio was very low. This is the period of winter sleep, with fat accumulated in the autumn as the principal metabolic fuel. In the winter, leptin, ghrelin, and GH may work in synergy to increase lipolysis. GH may also induce winter sleep to the raccoon dog. Fasting had no effect on the hormone levels, unlike in humans and rodents. Instead of the amount of fat in the body, the main regulators of the levels of these hormones in the raccoon dog are presumably seasonal rhythms entrained by melatonin.