Thyroid function derangement and childhood obesity: an Italian experience

Background

In recent years, there has been an increasing attention to thyroid function in paediatric obese patients. In the present study we aimed 1) to determine the prevalence of abnormally elevated thyroid-stimulating hormone (TSH) levels in Italian obese children and adolescents 2) to investigate whether hyperthyrotropinemia in obese children cardiovascular and metabolic risk factors 3) to verify if TSH elevation is reversible after weight loss.

Methods

We examined 938 obese children and adolescents (450 females). Anthropometric, metabolic and hormonal variables were determined at baseline and, in a subgroup of children with hyperthyrotropinemia, after a six month weight loss program.

Results

Hyperthyrotropinemia (TSH ≥4.2 μUI/ml) was diagnosed in 120 patients (12,8%). Body mass index (BMI) z-score (p = 0.02) and free T3 (fT3) levels (p = 0.03) were higher in patients with elevated TSH compared to the group with normal TSH. There were not significant differences in other metabolic parameters between the two groups. A positive correlation between baseline TSH and BMI z-score (p = 0.0045) and between Ft3 and BMI z-score (p = 0.0034) was observed, while there was no correlation between TSH and lipids. Twenty-three patients among those with hyperthyrotropinemia who participated to weight reduction intervention (64 patients), presented substantial weight loss and concomitantly a significant decrease in TSH and in fT3.

Conclusions

These results suggest that: (1) a moderate elevation of TSH concentrations, is frequently found in obese children; (2) in obese children increase of TSH is not associated to metabolic risk factors, (3) hyperthyrotropinemia is reversible after weight loss and these data suggest that it should not be treated.     

Geographical variation in temporal and spatial vocalization patterns of male harbour seals in the mating season

In the aquatically mating harbour seal, Phoca vitulina, oestrous females show marked differences in spatial and temporal distribution between geographical areas. This suggests that the males' display behaviour may also vary between areas. We recorded male vocalizations in two areas, the Moray Firth and Orkney, U.K. In the Moray Firth, females haul out on a few intertidal sandbars and travel along predictable routes to forage at sea. In Orkney, female haul out sites are much less influenced by tidal availability and females are much more dispersed. In the Moray Firth, males vocalized only during a short mating season, from 1 July to 12 August. Vocalizations varied significantly with the tide, the peak at high tide clearly coinciding with the period when most females were in the water. In contrast, vocalizations in Orkney were significantly related to both tidal and diel patterns. We suggest that the timing of male vocalizations reflects differences in female availability between sites. In the inner Moray Firth, vocalizations were heard throughout the females' range, whereas vocalizations in Orkney were heard only in two discrete areas. However, at both sites the density of vocalizing males was highest in narrow channels and/or along predictable female travel routes. Therefore, males clearly adapt their temporal and spatial behaviour patterns to variations in female distribution and density. These results suggest that male mating strategies in aquatically mating pinnipeds are more variable than was previously envisaged. Copyright 1999 The Association for the Study of Animal Behaviour.     

A novel hyperekplexia-causing mutation in the pre-transmembrane segment 1 of the human glycine receptor alpha1 subunit reduces membrane expression and impairs gating by agonists

In this study, we have compared the functional consequences of three mutations (R218Q, V260M, and Q266H) in the alpha(1) subunit of the glycine receptor (GlyRA1) causing hyperekplexia, an inherited neurological channelopathy. In HEK-293 cells, the agonist EC(50s) for glycine-activated Cl(-) currents were increased from 26 microm in wtGlyRA1, to 5747, 135, and 129 microm in R218Q, V260M, and Q266H GlyRA1 channels, respectively. Cl(-) currents elicited by beta-alanine and taurine, which behave as agonists at wtGlyRA1, were decreased in V260M and Q266H mutant receptors and virtually abolished in GlyRA1 R218Q receptors. Gly-gated Cl(-) currents were similarly antagonized by low concentrations of strychnine in both wild-type (wt) and R218Q GlyRA1 channels, suggesting that the Arg-218 residue plays a crucial role in GlyRA1 channel gating, with only minor effects on the agonist/antagonist binding site, a hypothesis supported by our molecular model of the GlyRA1 subunit. The R218Q mutation, but not the V260M or the Q266H mutation, caused a marked decrease of receptor subunit expression both in total cell lysates and in isolated plasma membrane proteins. This decreased expression does not seem to explain the reduced agonist sensitivity of GlyRA1 R218Q channels since no difference in the apparent sensitivity to glycine or taurine was observed when wtGlyRA1 receptors were expressed at levels comparable with those of R218Q mutant receptors. In conclusion, multiple mechanisms may explain the dramatic decrease in GlyR function caused by the R218Q mutation, possibly providing the molecular basis for its association with a more severe clinical phenotype.     

Oncology drug discovery applications using the FMAT 8100 HTS system

High-throughput screening (HTS) for potential anticancer agents requires a broad portfolio of assay platforms that may include kinase enzyme assays, protein-protein binding assays, and functional cell-based apoptosis assays. The authors have explored the use of fluorometric microvolume assay technology (the FMAT 8100 HTS System) in three distinct homogeneous HTS assays: (1). a Src tyrosine kinase enzyme assay, (2). a Grb2-SH2 protein-peptide interaction assay, and (3). an annexin V binding apoptosis assay. Data obtained from all three assays suggest that the FMAT system should facilitate the implementation of homogeneous assays for a wide variety of molecular targeted and cell-based screens.     

A limited survey of aflatoxins and fumonisins in retail maizebased products in the UK using immunoassay detection

A total of 27 maize-based products destined for human consumption were collected from retail outlets within the city of Glasgow in the UK and were analysed for the presence of aflatoxins using immunoaftinity column chromatography with fluorescence detection and for fumonisins by competitive ELISA. Aflatoxins were detected at a trace level below 4 in eight (30%) of the 27 samples tested, no sample contained aflatoxins at a high level although one sample of sweetcorn did contain aflatoxins at a level of 5-10 Fumonisins were detected in eight (30%) of the samples at levels from 1 to 8mgkg^-1 and a further eight samples contained fumonisin at a level below 1 mgkg^-1 but above the detectable level. The highest concentration of fumonisins was found in a sample of fine corn meal at 8-12mgkg^-1.     

Histochemical data on the liver of the marmoset (Callithrix jacchus).

The histochemistry of the hepatic parenchymal cells was studied in four Callithrix jacchus. A large amount of glycogen was noted throughout the lobules while the UDPG-GT and the phosphorylases were found unevenly distributed by the hepatic strands with different degrees of reactivity. Near the central vein one of the livers showed PAS-positive nuclear corpuscles that were more conspicuous in the hepatic cells with a larger amount of cytoplasmic glycogen and weaker UDPG-GT and phosphorylase reactivities. G-6PA (in a larger amount) and LDH (in a moderate amount) were found evenly distributed in the hepatic strands. F-1-6PA was seen sometimes with a stronger reactivity at the peripheral part of the lobules. The enzymes of the pentose shunt (G-6PDH, 6-PGDH and NADPH-2-TR) reacted strongly and as a rule evenly distributed near the hepatic lobules. Occasionally they reacted more intensely in the row of hepatic cells disposed just around the central vein. Cytochrome oxidase showed a very faint reaction. Cis-aconitase and ICDH were weak or moderate. NADH-2-TR more than SDH more than MDH were seen frequently diffused near the hepatic strands. SDH and MDH in some instances showed a stronger reactivity in the row or group of hepatic cells around the central vein. ATPase at pH 6.3 was negative in the marmoset liver; ATPase at pH 7.4 was mainly found in the wall of the portal area vessels; ATPase at pH 8.5 showed a stronger reactivity in the cytoplasm of the hepatic cells and ATPase at pH 9.4 was more abundant in the bile capillaries. The reactivity of the lipid metabolism enzymes was moderate with regard to alpha-GPDH or negligible with regard to beta-OHBDH. Acid phosphatase showed a stronger reaction, but almost limited to the Kupffer cells. The hepatic cells showed only a moderate amount of RNA. Some enzymes of the protein metabolism, such as GDH and leucine aminopeptidase showed a stronger reactivity while some others, such as alanyl aminopeptidase and MAO, were seen diffused near the hepatic lobules in a small amount. Enzymes of the mucopolysaccharide metabolism were not found at all (beta-glucuronidase) or showed only a weak reactivity, such as xylitol dehydrogenase.     

Co-Infection and Wild Animal Health: Effects of Trypanosomatids and Gastrointestinal Parasites on Coatis of the Brazilian Pantanal

Wild animals are infected by diverse parasites, but how they influence host health is poorly understood. We examined the relationship of trypanosomatids and gastrointestinal parasites with health of wild brown-nosed coatis (Nasua nasua) from the Brazilian Pantanal. We used coati body condition and hematological parameters as response variables in linear models that were compared using an information theoretic approach. Predictors were high/low parasitemias by Trypanosoma cruzi and T. evansi, and indices representing the abundance of distinct groups of gastrointestinal parasites. We also analyzed how host health changed with host sex and reproductive seasonality. Hemoparasites was best related to coati body condition and hematological indices, whereas abundance of gastrointestinal parasites was relatively less associated with coati health. Additionally, some associations were best predicted by models that incorporated reproductive seasonality and host sex. Overall, we observed a lower health condition during the breeding season, when coatis are under reproductive stress and may be less able to handle infection. In addition, females seem to handle infection better than males. Body condition was lower in coatis with high parasitemias of T. evansi, especially during the reproductive season. Total red blood cell counts, packed cell volume, platelets and eosinophils were also lower in animals with high T. evansi parasitemias. Total white blood cell counts and mature neutrophils were lower in animals with high parasitemias for both Trypanosoma species, with neutrophils decreasing mainly during the reproductive season. Overall, decreases in hematological parameters of females with T. evansi high parasitemias were less evident. For T. cruzi, monocytes decreased in individuals with high parasitemias. High abundances of microfilariae in the bloodstream, and cestode eggs and coccidian oocysts in feces were also associated with coati blood parameters. This study shows the potential value of examining hematological parameters as an approach to better understand the ecological relevance of parasite-host interactions.     

Intensive nitrogen loss over the Omani Shelf due to anammox coupled with dissimilatory nitrite reduction to ammonium

A combination of stable isotopes (¹⁵N) and molecular ecological approaches was used to investigate the vertical distribution and mechanisms of biological N₂ production along a transect from the Omani coast to the central–northeastern (NE) Arabian Sea. The Arabian Sea harbors the thickest oxygen minimum zone (OMZ) in the world''s oceans, and is considered to be a major site of oceanic nitrogen (N) loss. Short (<48 h) anoxic incubations with ¹⁵N-labeled substrates and functional gene expression analyses showed that the anammox process was highly active, whereas denitrification was hardly detectable in the OMZ over the Omani shelf at least at the time of our sampling. Anammox was coupled with dissimilatory nitrite reduction to ammonium (DNRA), resulting in the production of double-¹⁵N-labeled N₂ from ¹⁵NO₂⁻, a signal often taken as the lone evidence for denitrification in the past. Although the central–NE Arabian Sea has conventionally been regarded as the primary N-loss region, low potential N-loss rates at sporadic depths were detected at best. N-loss activities in this region likely experience high spatiotemporal variabilities as linked to the availability of organic matter. Our finding of greater N-loss associated with the more productive Omani upwelling region is consistent with results from other major OMZs. The close reliance of anammox on DNRA also highlights the need to take into account the effects of coupling N-transformations on oceanic N-loss and subsequent N-balance estimates.     

Anaerobic ammonia oxidation in a fertilized paddy soil

Evidence for anaerobic ammonium oxidation in a paddy field was obtained in Southern China using an isotope-pairing technique, quantitative PCR assays and 16S rRNA gene clone libraries, along with nutrient profiles of soil cores. A paddy field with a high load of slurry manure as fertilizer was selected for this study and was shown to contain a high amount of ammonium (6.2–178.8 mg kg⁻¹). The anaerobic oxidation of ammonium (anammox) rates in this paddy soil ranged between 0.5 and 2.9 nmolN per gram of soil per hour in different depths of the soil core, and the specific cellular anammox activity observed in batch tests ranged from 2.9 to 21 fmol per cell per day. Anammox contributed 4–37% to soil N2 production, the remainder being due to denitrification. The 16S rRNA gene sequences of surface soil were closely related to the anammox bacteria ‘Kuenenia'', ‘Anammoxoglobus'' and ‘Jettenia''. Most of the anammox 16S rRNA genes retrieved from the deeper soil were affiliated to ‘Brocadia''. The retrieval of mainly bacterial amoA sequences in the upper part of the paddy soil indicated that nitrifying bacteria may be the major source of nitrite for anammox bacteria in the cultivated horizon. In the deeper oxygen-limited parts, only archaeal amoA sequences were found, indicating that archaea may produce nitrite in this part of the soil. It is estimated that a total loss of 76 g N m⁻² per year is linked to anammox in the paddy field.