Identification of exposed components on the surface of adult Schistosoma mansoni by lactoperoxidase-catalysed iodination

Adult schistosomes have been labelled with ¹²⁵I using the lactoperoxidase-catalysed technique modified to cause minimal worm damage. After surface membrane removal and characterization, at least 13 labelled proteins were identified together with a large amount of labelled glycolipids, free fatty acids and phospholipids, especially phosphatidyl ethanolamine. Cationised ferritin has been used to stimulate surface membrane turnover of iodinated worms and the shedding of covalently bound ¹²⁵I-counts used as an index of turnover. Finally worms have been iodinated before and after stimulation of membrane turnover in chemically defined media and the patterns of labelled proteins were compared.     

A monoclonal immunoglobulin G1 in which some molecules possess glycosylated light chains--I. Site of glycosylation

A human monoclonal IgG1_κ protein (Hom) was found to possess two species of light chain with molecular weights of 23,000 and 28,000 respectively. The difference in mass was due to the presence of a carbohydrate prosthetic group on the 28,000 dalton species. The two species of light chain were separated by chromatography on CM-cellulose. Circular dichroism failed to detect any significant differences in conformation between the glycosylated and non-glycosylated forms and both species recombined with a heavy chain in an identical fashion as judged by difference spectroscopy. An anti-idiotypic antibody raised against the glycosylated Fab-fragment of IgGlHom was unable to distinguish between this species and the non-glycosylated Fab fragment, suggesting that the structure of the combining site is identical or very similar in both molecules. Amino-acid sequence analyses showed that both light chains had an identical sequence up to residue 41. Further studies on the glycosylated light chain, using o-iodosobenzoic acid fragments, localized the carbohydrate attachment site to asparagine 107, the penultimate residue of the J_κ region which links V_κ to C_κ. The sequence around the attachment site was Asn-Arg-Thr which satisfies the requirements for an acceptor sequence. The non-glycosylated light chain was found to have the same sequence in this region indicating that the absence of glycosylation was not due to the lack of an acceptor sequence. A kinetic mechanism has been proposed to account for the incomplete glycosylation of the light chains of IgG1Hom in which there is a competition between the rate of folding of the nascent polypeptide and the rate of attachment of core sugars via the dolichol pyrophosphate pathway.     

Ethyl pyruvate and ethyl lactate down-regulate the production of pro-inflammatory cytokines and modulate expression of immune receptors

Esters of alpha-oxo-carbonic acids such as ethyl pyruvate (EP) have been demonstrated to exert inhibitory effects on the production of anti-inflammatory cytokines. So far, there is no information about effects, if any, of ethyl lactate (EL), an obviously inactive analogue of EP, on inflammatory immune responses. In the present study, we provide evidence that the anti-inflammatory action of alpha-oxo-carbonic acid esters is mediated by inhibition of glyoxalases (Glo), cytosolic enzymes that catalyse the conversion of alpha-oxo-aldehydes such as methylglyoxal (MGO) into the corresponding alpha-hydroxy acids using glutathione as a cofactor. In vitro enzyme activity measurements revealed the inhibition of human Glo1 by alpha-oxo-carbonic acid esters, whilst alpha-hydroxy-carbonic acid esters such as EL were not inhibitory. In contrast, both EP and EL were shown to suppress the Lipopolysaccharide (LPS)-induced production of pro-inflammatory cytokines such as tumor necrosis factor-alpha, interleukin (IL)-1beta, IL-6 and IL-8 from human immunocompetent cells, and modulated the expression of the immune receptors HLA-DR, CD14 and CD91 on human monocytes. Here, we show a crossing link between glyoxalases and the immune system. The results described herein introduce glyoxalases as a possible target for therapeutic approaches of immune suppression.     

Dietary turmeric modulates DMBA-induced p21ras, MAP kinases and AP-1/NF-kappaB pathway to alter cellular responses during hamster buccal pouch carcinogenesis

The chemopreventive efficacy of turmeric has been established in experimental systems. However, its mechanism(s) of action are not fully elucidated in vivo. The present study investigates the mechanism of turmeric-mediated chemoprevention in 7,12-dimethylbenz(a)anthracene (DMBA)-induced hamster buccal pouch (HBP) carcinogenesis at 2, 4, 6, 10 and 12 weeks. Dietary turmeric (1%) led to decrease in DMBA-induced tumor burden and multiplicity, and enhanced the latency period in parallel, to its modulatory effects on oncogene products and various cellular responses during HBP tumorigenesis. DMBA-induced expression of ras oncogene product, p21 and downstream target, the mitogen-activated protein kinases were significantly decreased by turmeric during HBP carcinogenesis. Turmeric also diminished the DMBA-induced mRNA expression of proto-oncogenes (c-jun, c-fos) and NF-κB, leading to decreased protein levels and in further attenuation of DMBA-induced AP-1/NF-κB DNA-binding in the buccal pouch nuclear extracts. Besides, buccal pouch of hamsters receiving turmeric diet showed significant alterations in DMBA-induced effects: (a) decrease in cell proliferation (diminished PCNA and Bcl2 expression), (b) enhanced apoptosis (increased expression of Bax, caspase-3 and apoptotic index), (c) decrease in inflammation (levels of Cox-2, the downstream target of AP-1/NF-κB, and PGE2) and (d) aberrant expression of differentiation markers, the cytokeratins (1, 5, 8, and 18). Together, the protective effects of dietary turmeric converge on augmenting apoptosis of the initiated cells and decreasing cell proliferation in DMBA-treated animals, which in turn, is reflected in decreased tumor burden, multiplicity and enhanced latency period. Some of these biomarkers are likely to be helpful in monitoring clinical trials and evaluating drug effect measurements.     

Biophysical modeling of neural plasticity induced by transcranial magnetic stimulation

Transcranial magnetic stimulation (TMS) is a widely used noninvasive brain stimulation method capable of inducing plastic reorganisation of cortical circuits in humans. Changes in neural activity following TMS are often attributed to synaptic plasticity via process of long-term potentiation and depression (LTP/LTD). However, the precise way in which synaptic processes such as LTP/LTD modulate the activity of large populations of neurons, as stimulated en masse by TMS, are unclear. The recent development of biophysical models, which incorporate the physiological properties of TMS-induced plasticity mathematically, provide an excellent framework for reconciling synaptic and macroscopic plasticity. This article overviews the TMS paradigms used to induce plasticity, and their limitations. It then describes the development of biophysically-based numerical models of the mechanisms underlying LTP/LTD on population-level neuronal activity, and the application of these models to TMS plasticity paradigms, including theta burst and paired associative stimulation. Finally, it outlines how modeling can complement experimental work to improve mechanistic understandings and optimize outcomes of TMS-induced plasticity.     

Measurement of Trabecular Bone Score of the Spine by Low-Dose Imaging System (EOS®): A Feasibility Study

Purpose/Introduction: Measurement of trabecular bone score (TBS^®) of the lumbar spine on dual energy X-ray absorptiometry (DXA) devices improves fracture risk prediction. We conducted a proof of concept study to assess the feasibility of TBS^® measured on the low-dose imaging system EOS^®. Methods: TBS was assessed on both DXA and EOS^® in 122 patients aged ≥ 50 yr, receiving no anti-osteoporotic treatment. The TBS^® was computed on full-body EOS^® images, focusing on the lumbar spine region. The patients were also scanned with a DXA bone densitometer (Hologic) and the spine and hip bone mineral density (g/cm²) were computed. Results: TBS^® measurement on EOS^® was not possible in 34 patients due to technical problems. It could be measured on both DXA and EOS^® in 88 patients (28 with severe low-trauma fracture and 60 without fracture). TBS-EOS values were significantly lower in fractured patients compared to nonfractured patients. TBS-EOS was associated with the presence of fractures as reported by an AUC of 0.70. Odds ratio of TBS-EOS for the presence of severe low-trauma fracture was 2.00 [1.24–3.25], p?=?0.005. Conclusions: This proof of concept study, based on a prototype version of the TBS-EOS, demonstrated the feasibility of the measurement of TBS^® on low-dose EOS^® imaging devices. Results show that the TBS-EOS was lower in patients with severe low-trauma fractures compared to nonfractured patients independently from bone mineral density. Some technical issues need to be solved before its eventual use in routine clinical settings. Additional prospective studies are still needed to define the actual contribution of this new technique.     

Demonstration of short-term plasticity in the dorsolateral prefrontal cortex with theta burst stimulation: A TMS-EEG study

Objectives

To examine the effects of intermittent TBS (iTBS) and continuous TBS (cTBS) on cortical reactivity in the dorsolateral prefrontal cortex.

A possible mechanism of low molecular weight protein tyrosine phosphatase (LMW-PTP) activity modulation by glutathione action during human osteoblast differentiation

Objective

Low molecular weight protein tyrosine phosphatases (LMW-PTPs) are a family of enzymes strongly involved in the regulation of cell growth and differentiation. Since there is no information concerning the relationship between osteoblastic differentiation and LMW-PTP expression/activity, we investigated its involvement during human osteoblast-like cells (hFOB 1.19) differentiation. It is known that LMW-PTP is regulated by an elegant redox mechanism, so we also observed how the osteoblastic differentiation affected the reduced glutathione levels.

Design

hFOB 1.19 cells were cultured in DMEM/F12 up to 35 days. The osteoblast phenotype acquisition was monitored by measuring alkaline phosphatase activity and mineralized nodule formation by Von Kossa staining. LMW-PTP activity and expression were measured using the p-nitrophenylphosphate as substrate and Western blotting respectively. Crystal violet assay determined the cell number in each experimental point. Glutathione level was determined by both HPLC and DNTB assays.

Results

LMW-PTP modulation was coincident with the osteoblastic differentiation biomarkers, such as alkaline phosphatase activity and presence of nodules of mineralization in vitro. Likewise LMW-PTP, the reduced glutathione-dependent microenvironment was modulated during osteoblastic differentiation. During this process, LMW-PTP expression/activity, as well as alkaline phosphatase and glutathione increased progressively up to the 21st day (p < 0.001) of culturing, decreasing thereafter.

Conclusions

Our results clearly suggest that LMW-PTP expression/activity was rigorously modulated during osteoblastic differentiation, possibly in response to the redox status of the cells, since it seems to depend on suitable levels of reduced glutathione. In this way, we pointed out LMW-PTP as an important signaling molecule in osteoblast biology and bone formation.     

KSHV genotypes A and C are more frequent in Kaposi sarcoma lesions from Brazilian patients with and without HIV infection, respectively

Macrophages play an important role in tumor inflammatory microenvironment, lipoxin (LX), the 'stop signal' for inflammation, has been extensively studied preclinically for its anti-inflammatory or inflammatory pro-resolving effect. Here, we showed that LXA(4) could promote the apoptosis and inhibit the proliferation, migration and angiogenesis of HepG2 hepatocarcinoma cells stimulated by lipopolysaccharide (LPS) or activated macrophage-conditioned media (ACM). Moreover, BML-111, the analog of LXA(4), effectively inhibited the proliferation, invasion and angiogenesis of tumor in H22 hepatocarcinoma cell bearing mice. These results showed that LXA(4) could be a possible candidate for liver cancer therapy, and blocking the activation of macrophages would be an effective drug target.     

Stimulation magnétique transcrânienne répétée (rTMS) dans le traitement de la schizophrénie : intérêts et perspectives

rTMS is increasingly used in the treatment of patients with schizophrenia. In this paper, we proposed a review of the literature on the subject. Current data show a moderate efficacy of rTMS at low frequency auditory hallucinations and suggest a potential benefit of this technology at high frequency in the treatment of negative symptoms. The TBS emerging variant of rTMS could bring an additional benefit seen its stronger effects.