Placental transfer of maternally-derived IgA precludes the use of guthrie card eluates as a screening tool for primary immunodeficiency diseases

There is a need for neonatal screening tools to improve the long-term clinical outcome of patients with primary immunodeficiency diseases (PID). Recently, a PCR-based screening method for both TRECs and KRECs using Guthrie card samples has been developed. However, the applicability of these excision circle assays is limited to patients with severe T or B cell lymphopenia (SCID, XLA and A-T), whereas the most common forms of PID are not detected. Absence of serum IgA is seen in a major fraction of patients with immunological defects. As serum IgA in newborns is considered to be of fetal origin, eluates from routinely collected dried blood spot samples might thus be suitable for identification of children with PID. To assess the applicability of such screening assays, stored Guthrie card samples were obtained from 47 patients with various forms of primary immunodeficiency diseases (SCID, XLA, A-T, HIGM and IgAD), 20 individuals with normal serum IgA levels born to IgA-deficient mothers and 51 matched healthy newborns. Surprisingly, normal serum IgA levels were found in all SCID, XLA, A-T and HIGM patients and, additionally, in all those IgAD patients born to IgA-sufficient mothers. Conversely, no serum IgA was found in any of the 16 IgAD patients born by IgA-deficient mothers. Moreover, half of the IgA-sufficient individuals born by IgA-deficient mothers also lacked IgA at birth whereas no IgA-deficient individuals were found among the controls. IgA in neonatal dried blood samples thus appears to be of both maternal and fetal origin and precludes its use as a reliable marker for neonatal screening of primary immunodeficiency diseases.     

Root uptake of cationic amino acids by Arabidopsis depends on functional expression of amino acid permease 5

* Specific transporters mediate uptake of amino acids by plant roots. Earlier studies have indicated that the lysine histidine transporter 1 and amino acid permease 1 participate in this process, but although plant roots have been shown to absorb cationic amino acids with high affinity, neither of these transporters seems to mediate transport of L-arginine (L-Arg) or L-lysine (L-Lys). * Here, a collection of T-DNA knockout mutants were screened for alterations in Arabidopsis root uptake rates of L-Arg and it was found that only the AAP5 mutant displayed clear phenotypic divergence on high concentrations of L-Arg. A second screen using low concentrations of (15)N-labelled L-Arg in the growth media also identified AAP5 as being involved in L-Arg acquisition. * Momentaneous root uptake of basic amino acids was strongly affected in AAP5 mutant lines, but their uptake of other types of amino acids was only marginally affected. Comparisons of the root uptake characteristics of AAP5 and LHT1 mutants corroborated the hypothesis that the two transporters have distinct affinity spectra in planta. * Root uptake of all tested amino acids, except L-aspartic acid (L-Asp), was significantly affected in double AAP5*LHT1 mutants, suggesting that these two transporters account for a major proportion of roots' uptake of amino acids at low concentrations.     

Single muscle fiber adaptations to resistance training in old (>80 yr) men: evidence for limited skeletal muscle plasticity

The purpose of this study was to investigate whole muscle and single muscle fiber adaptations in very old men in response to progressive resistance training (PRT). Six healthy independently living old men (82 +/- 1 yr; range 80-86 yr, 74 +/- 4 kg) resistance-trained the knee extensors (3 sets, 10 repetitions) at approximately 70% one repetition maximum 3 days/wk for 12 wk. Whole thigh muscle cross-sectional area (CSA) was assessed before and after PRT using computed tomography (CT). Muscle biopsies were obtained from the vastus lateralis before and after the PRT program. Isolated myosin heavy chain (MHC) I and IIa single muscle fibers (n = 267; 142 pre; 125 post) were studied for diameter, peak tension, shortening velocity, and power. An additional set of isolated single muscle fibers (n = 2,215; 1,202 pre; 1,013 post) was used to identify MHC distribution. One repetition maximum knee extensor strength increased (P < 0.05) 23 +/- 4 kg (56 +/- 4 to 79 +/- 7 kg; 41%). Muscle CSA increased (P < 0.05) 3 +/- 1 cm2 (120 +/- 7 to 123 +/- 7 cm2; 2.5%). Single muscle fiber contractile function and MHC distribution were unaltered with PRT. These data indicate limited muscle plasticity at the single-muscle fiber level with a resistance-training program among the very old. The minor increases in whole muscle CSA coupled with the static nature of the myocellular profile indicate that the strength gains were primarily neurological. These data contrast typical muscle responses to resistance training in young ( approximately 20 yr) and old ( approximately 70 yr) humans and indicate that the physiological regulation of muscle remodeling is adversely modified in the oldest old.     

Occurrence of neurotrophin receptors and transmitters in the developing Xenopus gut

The ontogeny of gut innervation in the anuran amphibian Xenopus laevis was studied using immunohistochemistry on sections of whole larvae from NF stages 38-52. Immunoreactivity to acetylated tubulin confirmed the presence of nerve fibres as early as stages 38-39. Actin immunoreactivity was found at stage 41, indicating the presence of smooth muscle cells. Trk-like neurotrophin receptors were occasionally found in nerve fibres as soon as stages 38-39. Vasoactive intestinal polypeptide (VIP) and pituitary adenylate cyclase-activating peptide (PACAP) immunoreactivities coexisted in nerves innervating the gut wall from stages 40-41, and nitric oxide synthase (NOS) from stage 42. Substance P/neurokinin A (SP/NKA) occurred at stage 42. In all these cases, the first fibres were observed in the oesophagus. Calcitonin gene-related peptide (CGRP) was first observed in nerves at stage 48. In general, VIP/PACAP and NOS innervation was denser than the tachykinin innervation. In conclusion, the development of nerve fibres in the Xenopus gut is probably dependent on neurotrophins that may act via Trk-like receptors and occur before the gut wall is fully organised morphologically. Feeding in Xenopus larvae starts at NF stage 45. The study demonstrates that several of the transmitters investigated are expressed in the gut innervation (and in endocrine cells) prior to this stage.     

Sexual signaling in the European bitterling: females learn the truth by direct inspection of the resource

In many taxa females appear to base their mate choice on multipletraits. But the relative importance of different traits inmate choice has rarely been determined. Here we show that femalesof a freshwater fish, the European bitterling, Rhodeus sericeus,base their mate choice on multiple traits that differ in theirreliability as indicators of expected reproductive successand are used at different stages of the decision process. Theinitial decision to inspect a male is based on male behaviorand red coloration, whereas the final spawning decision isbased on the quality of the live unionid mussel, Anodonta anatina,that the male is defending as an oviposition site. Male traitsmay indicate which males are worth inspecting by reflectingmale quality, such as reproductive condition and genetic constitution.Male traits do not, however, reflect mussel quality, as bright males also court females vigorously toward mussels that yielda low probability of survival of the offspring. Females, onthe other hand, are choosier than males in their choice ofspawning site and seem to gain reliable information about thesurvival probability of the eggs by inspecting the mussel directly.     

Morphological and genetic variation of Fucus in the eastern Gulf of Bothnia,northern Baltic Sea

Fucus vesiculosus and F. radicans (Phaeophyceae) are important habitat-formers on rocky shores in the Bothnian Sea. While both species occur sympatrically along the entire western Bothnian Sea coast, F. radicans has been found only in the northern part of the eastern coast. According to previous studies, the two species can be distinguished based on morphology, F. radicans having narrower thalli and a bushier appearance. However, marine mapping in the eastern Bothnian Sea has revealed that high morphological variation in Fucus, partly caused by gradients in salinity and exposure, makes differentiation between the two species difficult. We studied morphological and genetic variation to find out whether the two Fucus species can be differentiated in the south-eastern Bothnian Sea, and if F. radicans occurs in the area. The study was carried out in six subareas including 350 km of coast, with a salinity gradient of 3.5–6.5 PSU, and varying wave exposure. We found a gradual change towards smaller and narrower thalli and a higher number of holdfasts in Fucus populations when moving northwards to lower salinities. Distinct Fucus morphs were often found within the study sites but the morphs were genetically differentiated only at one study site in the Skaftung subarea, suggesting the occurrence of both species. However, in the Vasa subarea the sample size for analysing genetic differentiation was low due to high clonality. In the Luvia subarea south of Skaftung, Fucus morphology corresponded to that of F. radicans in earlier studies but the population was genetically more similar to F. vesiculosus in the southern subareas. We conclude that by using only morphological characteristics it is not possible to differentiate between the two species in central and northern parts of the eastern Bothnian Sea. Based on genetic analyses, the southernmost known occurrence of F. radicans in the eastern Bothnian Sea is in Skaftung.     

Plasma variation and reproducibility of oxidized LDL-cholesterol and low-grade inflammation biomarkers among participants of the Malmö Diet and Cancer cohort

Context: Large epidemiological studies often collect non-fasting samples, although the reliability of biomarkers may be uncertain.

Objective: To explore the reliability and reproducibility of a single measurement of selected biomarkers in a sub-sample of the Malmö Diet and Cancer cohort.

Methods: We estimated single- and average-measures intraclass correlation coefficients (ICC) for oxidized (ox)-LDL, interleukin (IL)-1β, IL-6, IL-8 and TNF-α.

Results: Single-measures ICC in non-fasting samples of ox-LDL, IL-1β, IL-6, IL-8 and TNF-α were the following: 0.85, 0.71, 0.61, 0.78 and 0.66 for men, and 0.67, 0.81, 0.87, 0.69 and 0.81 for women. Biomarkers at non-fasting and fasting samples were highly correlated (all r?>?0.80).

Conclusions: The observed ICC suggest that most of the examined biomarkers (non-fasting blood) would allow meaningful analysis in epidemiological studies.