Dujardinascaris mormyropsis n. sp. (Nematoda: Anisakidae) from the osteoglossiform fish Mormyrops anguilloides (Linnaeus) (Mormyridae) in Central Africa

A new nematode species, Dujardinascaris mormyropsis n. sp. (Anisakidae), is described from specimens found in the stomach and intestine of the cornish jack Mormyrops anguilloides (Linnaeus) (Osteoglossiformes; Mormyridae) in the Sangha River (Congo River basin) in Dzanga-Sangha Protected Areas, Central African Republic. Based on light and scanning electron microscopical examination, the new species differs from the only other congeneric species parasitising fishes in Africa, D. malapteruri (Baylis, 1923), mainly in the presence of dentigerous ridges on lips, absence of lateral caudal alae in the cloacal region, in the anteriorly curved, non-bifid distal tip of the gubernaculum and larger eggs (60–90 × 52–78 vs 45 × 30 μm); males of D. mormyropsis are characterised by the presence of a ventral precloacal cuticular ornamentation not observed in other Dujardinascaris spp. Dujardinascaris mormyropsis and D. malapteruri also differ in the order of their fish hosts (Osteoglossiformes vs Siluriformes). Specimens previously reported as Dujardinascaris graberi Troncy, 1969, a junior synonym of D. malapteruri, from Mormyrops engystoma Boulenger in Chad belong to the new species D. mormyropsis.     

A comparative study of muscle force estimates using Huxley's and Hill's muscle model

Determination of muscle forces in individual muscles is often essential to assess optimal performance of human motion. Inverse dynamic methods based on the kinematics of the given motion and on the use of optimisation approach are the most widely used for muscle force estimation. The aim of this study was to estimate how the choice of muscle model influences predicted muscle forces. Huxley's (1957, Prog Biophys Biop Chem. 7: 255–318) and Hill's (1938, Proc R Soc B. 126: 136–195) muscle models were used for determination of muscle forces of two antagonistic muscles of the lower extremity during cycling. Huxley's model is a complex model that couples biochemical and physical processes with the microstructure of the muscle whereas the Hill's model is a phenomenological model. Muscle forces predicted by both models are within the same range. Huxley's model predicts more realistic patterns of muscle activation but it is computationally more demanding. Therefore, if the overall muscle forces are to be assessed, it is reasonable to use a simpler implementation based on Hill's model.     

Structure-Activity Relationships of Novel Salicylaldehyde Isonicotinoyl Hydrazone (SIH) Analogs: Iron Chelation,Anti-Oxidant and Cytotoxic Properties

Salicylaldehyde isonicotinoyl hydrazone (SIH) is a lipophilic, tridentate iron chelator with marked anti-oxidant and modest cytotoxic activity against neoplastic cells. However, it has poor stability in an aqueous environment due to the rapid hydrolysis of its hydrazone bond. In this study, we synthesized a series of new SIH analogs (based on previously described aromatic ketones with improved hydrolytic stability). Their structure-activity relationships were assessed with respect to their stability in plasma, iron chelation efficacy, redox effects and cytotoxic activity against MCF-7 breast adenocarcinoma cells. Furthermore, studies assessed the cytotoxicity of these chelators and their ability to afford protection against hydrogen peroxide-induced oxidative injury in H9c2 cardiomyoblasts. The ligands with a reduced hydrazone bond, or the presence of bulky alkyl substituents near the hydrazone bond, showed severely limited biological activity. The introduction of a bromine substituent increased ligand-induced cytotoxicity to both cancer cells and H9c2 cardiomyoblasts. A similar effect was observed when the phenolic ring was exchanged with pyridine (i.e., changing the ligating site from O, N, O to N, N, O), which led to pro-oxidative effects. In contrast, compounds with long, flexible alkyl chains adjacent to the hydrazone bond exhibited specific cytotoxic effects against MCF-7 breast adenocarcinoma cells and low toxicity against H9c2 cardiomyoblasts. Hence, this study highlights important structure-activity relationships and provides insight into the further development of aroylhydrazone iron chelators with more potent and selective anti-neoplastic effects.     

Sward structure and diet selection after sheep introduction on abandoned grassland in the Giant Mts, Czech Republic

The effect of rotational grazing on the sward structure of long-term abandoned grassland and the sheep diet selection were investigated in the Giant Mts (Krkono?e/Karkonosze). The aim of the study was to answer the following questions: (1) Does sheep grazing affect the sward structure of previously abandoned mountain grassland? (2) How does sheep diet selection develop within and among grazing seasons? (3) Which section of a pasture do sheep prefer to graze? Data was collected three times during each grazing season in spring, summer and in autumn in the years 2001, 2002 and 2003 Fifty 1 × 1 m plots were used where the plant species occurrence and damage of plants by grazing for all species were repeatedly recorded. 1) Nonsignificant changes in plant species occurrences were recorded in spite of obvious visual changes in sward structure due to grazing e.g. the retreat of tall dominant species characteristic of long-term unmanaged grasslands. 2) Seasonal as well as inter-annual changes in sheep diet selection were detected. In spring 2001, sheep grazed over a wide variety of plant species in low quantities. In subsequent springs, they preferred species favoured during previous autumns (Veratrum album subsp. lobelianum; Ranunculus platanifolius; Senecio ovatus) and changed the diet only as a result of the elimination of favoured plants. 3) Sheep preferred to graze at the highest elevated part of the pasture probably as a consequence of anti-predator behaviour not due to higher occurrence of favoured plant species or the presence of a drinking place or salt licks. Changes in the sward structure were mostly of a quantitative not qualitative character, thus the presence-absence data collection is not a suitable method for monitoring the effects of management restoration. The diet selection changed probably due to the animals’ experience; sheep had no experience with montane species in spring 2001. The sheep were able to recognize favoured plant species after 6 months of wintering in lowland.     

HLA-E: strong association with beta2-microglobulin and surface expression in the absence of HLA class I signal sequence-derived peptides

The nonclassical class I HLA-E molecule folds in the presence of peptide ligands donated by the signal sequences of permissive class I HLA alleles, with the aid of TAP and tapasin. To identify HLA-E-specific Abs, four monoclonals of the previously described MEM series were screened by isoelectric focusing (IEF) blot and immunoprecipitation/IEF on >30 single-allele class I transfectants and HLA-homozygous B lymphoid cells coexpressing HLA-E and HLA-A, -B, -C, -F, or -G. Despite their HLA-E-restricted reactivity patterns (MEM-E/02 in IEF blot; MEM-E/07 and MEM-E/08 in immunoprecipitation), all of the MEM Abs unexpectedly reacted with beta(2)-microglobulin (beta(2)m)-free and denatured (but not beta(2)m-associated and folded) HLA-E H chains. Remarkably, other HLA-E-restricted Abs were also reactive with free H chains. Immunodepletion, in vitro assembly, flow cytometry, and three distinct surface-labeling methods, including a modified (conformation-independent) biotin-labeling assay, revealed the coexistence of HLA-E conformers with unusual and drastically antithetic features. MEM-reactive conformers were thermally unstable and poorly surface expressed, as expected, whereas beta(2)m-associated conformers were either unstable and weakly reactive with the prototypic conformational Ab W6/32, or exceptionally stable and strongly reactive with Abs to beta(2)m even in cells lacking permissive alleles (721.221), TAP (T2), or tapasin (721.220). Noncanonical, immature (endoglycosidase H-sensitive) HLA-E glycoforms were surface expressed in these cells, whereas mature glycoforms were exclusively expressed (and at much lower levels) in cells carrying permissive alleles. Thus, HLA-E is a good, and not a poor, beta(2)m assembler, and TAP/tapasin-assisted ligand donation is only one, and possibly not even the major, pathway leading to its stabilization and surface expression.     

Repetitive transcranial magnetic stimulation (rTMS) in major depressive episode during pregnancy

Sir: For women diagnosed with Recurrent depressive disorder, pregnancy poses a major treatment challenge. Apart from antidepressants, the most commonly used biological therapeutical method is ECT (electroconvulsive therapy). We believe that similar efficacy can be achieved using rTMS as a safer option with substantially less side effects. So far, only a few case-reports reporting the use of rTMS for treatment of pregnant patients with depression were published.     

Screening of boldenone and methylboldenone in bovine urine using disposable electrochemical immunosensors

Electrochemical based immunosensors for the detection of boldenone and methylboldenone in bovine urine were described in this paper. The immunosensors were fabricated by immobilizing boldenone-bovine serum albumin conjugate on the surface of screen-printed electrodes (SPEs), and followed by the competition between the free analyte and coating conjugate with corresponding antibodies. The use of anti-species IgG-horseradish peroxidase conjugate determined the degree of competition. The electrochemical technique chosen was chronoamperometry, performed at a potential of +100 mV whereby the product of the catalysis of 3,3′,5,5′-tetramethylbenzidine undergoes reduction produced by the enzyme label. The limits of detection of assay were 30.9 ± 4.3 pg ml⁻¹ for boldenone and 120.2 ± 8.2 pg ml⁻¹ for methylboldenone, respectively. Results of repeated analysis of each androgen carried out using three different batches of electrodes indicate suitable repeatability (EC₅₀ = 1.0 ± 0.3 ng ml⁻¹ (n = 3, N = 3), R² = 0.969, R.S.D. = 9.6% for boldenone and 1.5 ± 0.3 ng ml⁻¹, 0.971, 10.5% for methylboldenone, respectively). Urine samples were determined directly after a single dilution step, omitting extraction and hydrolysis. This method offers the advantage to pick up both boldenone and its major metabolites in an efficient manner due to the high cross-reactivity pattern of α-boldenone with this antibody. The concentration of methylboldenone in urine detected by developed methods does indicate methylboldenone administration to heifers. Gas chromatography coupled to mass spectrometry analysis was performed to quantitate the individual metabolites present in urine samples, and results were validated with both ELISA and immunosensor data.