Biochemical characterisation and novel classification of monofunctional S-adenosylmethionine decarboxylase of Plasmodium falciparum

Plasmodium falciparum like other organisms is dependent on polyamines for proliferation. Polyamine biosynthesis in these parasites is regulated by a unique bifunctional S-adenosylmethionine decarboxylase/ornithine decarboxylase (PfAdoMetDC/ODC). Only limited biochemical and structural information is available on the bifunctional enzyme due to the low levels and impurity of an instable recombinantly expressed protein from the native gene. Here we describe the high level expression of stable monofunctional PfAdoMetDC from a codon-harmonised construct, which permitted its biochemical characterisation indicating similar catalytic properties to AdoMetDCs of orthologous parasites. In the absence of structural data, far-UV CD showed that at least on secondary structure level, PfAdoMetDC corresponds well to that of the human protein. The kinetic properties of the monofunctional enzyme were also found to be different from that of PfAdoMetDC/ODC as mainly evidenced by an increased K(m). We deduced that complex formation of PfAdoMetDC and PfODC could enable coordinated modulation of the decarboxylase activities since there is a convergence of their k(cat) and lowering of their K(m). Such coordination results in the aligned production of decarboxylated AdoMet and putrescine for the subsequent synthesis of spermidine. Furthermore, based on the results obtained in this study we propose a new AdoMetDC subclass for plasmodial AdoMetDCs.     

Human immunodeficiency virus-1 infection protects against a Tc1-to-Tc2 shift in CD8(+) T cells

Despite the reports of dysfunction of the lytic abilities of CD8(+) T cells during human immunodeficiency virus-1 (HIV-1) disease progression, the effects of infection on the noncytolytic functions of CD8(+) T cells have not been well characterized to date. We examined the effect of HIV-1 infection on the cytokine and chemokine responses of peripheral blood-derived CD8(+) T cells in an in vitro system. Activation of HIV-1-infected CD8(+) T cells with phytohemagglutinin resulted in a 4- to 8-fold increase in the production of macrophage inflammatory protein (MIP)-1α, MIP-1β, regulated on activation normal T-cell expressed and secreted, and interleukin (IL)-16. Treatment of activated HIV-1-infected CD8(+) T cells with anti-CD3 monoclonal (M) antibody (Ab) and IL-15 induced strong production of interferon-γ (IFN-γ). Treatment of cells with anti-IL-12 MAb and IL-4 to induce a Tc1-to-Tc2 shift resulted in no change in viral production levels or IFN-γ production within the HIV-1-infected CD8(+) T cell population. Initiation of a Tc2-to-Tc1 shift resulted in a 6-fold increase in HIV-1 replication and 2- to 3-fold higher levels of IFN-γ, demonstrating that infection can protect against a Tc1-to-Tc2 shift in CD8(+) T cells.     

Novel association to the proprotein convertase PCSK7 gene locus revealed by analysing soluble transferrin receptor (sTfR) levels

The level of body iron storage and the erythropoietic need for iron are indicated by the serum levels of ferritin and soluble transferrin receptor (sTfR), respectively. A meta-analysis of five genome-wide association studies on sTfR and ferritin revealed novel association to the PCSK7 and TMPRSS6 loci for sTfR and the HFE locus for both parameters. The PCSK7 association was the most significant (rs236918, P = 1.1 × 10E-27) suggesting that proprotein convertase 7, the gene product of PCSK7, may be involved in sTfR generation and/or iron homeostasis. Conditioning the sTfR analyses on transferrin saturation abolished the HFE signal and substantially diminished the TMPRSS6 signal while the PCSK7 association was unaffected, suggesting that the former may be mediated by transferrin saturation whereas the PCSK7-associated effect on sTfR generation appears to be more direct.     

Infliximab in the treatment of rheumatoid meningoencephalitis

Journal of Neurology -     

Difficulties in the diagnosis of intracystic tumors of the female breast

The objective of the current study was to determine the accuracy of radiological and cytological diagnoses of intracystic and papillary lesions in distinguishing between true papillary benign and malignant lesions. Seventy cytological reports of intracystic proliferations were selected from our cytopathological database at the Breast Health Corporation, Budapest, Hungary, dating back to the last 7 years. Retrospective analysis of the diagnostic approaches--mammography, ultrasonography, clinical examination and cytology--was performed in selected cases. The results of imaging and cytological examination are routinely reported on a categorical scale ranging from 1 to 5. 44 patients underwent surgical excision: histology showed benign lesions in 21 and malignant lesions in 23 cases. Twelve patients, who did not undergo biopsy and presented a stable disease at follow-ups, were also included in the group of benign lesion. Fifteen patients were not available for follow-up. Concerning the total investigated cases the mean categorical values of mammography, ultrasonography and cytology were 2.24, 2.78 and 3.05 respectively. The malignant and benign groups significantly differ from each other concerning the mean age of the patients (p=0.0216), the distribution of the coded mammographical results (p= 0.0171) the cytological results (p=0.0001), and average tumor size measured on mammogram images (p=0.0199). The two group does not significantly differ over the distribution of mammographical density patterns (p=0.1075), radiomorphological appearance (p=0.1101), average tumor size measured on ultrasonography (p=0.2665), and patient complaints (p=0.2634). The evaluation of ultrasonography shows borderline significance (Pearson Chi-square test: p=0.0616, M-L Chi-square test: p=0.0404) between the malignant and benign groups. Differential diagnosis between malignant and benign intracystic and papillary lesions is feasible using common radiological diagnostics. However, more efficient teamwork is needed with the cooperation of a well-trained cytologist and radiologist, who are able to produce precise images of the lesions, and guides the aspiration of the adequate samples for cytology, which is the most valuable examination.     

Prolonged survival of porcine hepatocytes in cynomolgus monkeys

BACKGROUND & AIMS: Management of patients with liver failure can be a significant medical challenge, and transplantation of the liver is the only definitive therapy. Whole liver allotransplantation is limited by a shortage of human donors and the risks of the surgery in those most ill. Transplants consisting of xenogeneic hepatocytes might overcome these problems, and work in rodents indicates that such transplants can correct some metabolic deficiencies and can prevent the complications and mortality associated with hepatic failure. As a prelude to clinical application, we tested the feasibility of hepatocyte xenotransplantation in nonhuman primates. METHODS: One to 2 billion hepatocytes from outbred swine were transplanted into the spleens of cynomolgus monkeys using conventional immunosuppression to control rejection. Duration of graft function was determined based on assay for porcine albumin. RESULTS: Following a single infusion, xenogeneic hepatocytes functioned for more than 80 days and, following re-transplantation, for more than 253 days. Engraftment in the spleen was confirmed 40 days after transplantation by asialoglycoprotein receptor-directed nuclear scanning. The humoral immune response to the transplanted porcine cells had no discernible impact on the survival of the grafts. CONCLUSIONS: Xenotransplantation of hepatocytes should be explored as a readily available, minimally invasive form of therapy for hepatic failure.     

Early and long-term outcomes after surgical treatment in patients with aortic stenosis and severe left ventricular heart failure without concomitant coronary artery disease with respect to preoperative mean transvalvular pressure gradient

INTRODUCTION: There are limited data on early and long-term prognosis in patients after aortic valve replacement who have left ventricular dysfunction, reduced ejection fraction (EF) < or =35% and no concomitant coronary artery disease. AIM: To assess the prognosis in this group of patients depending on the mean aortic gradient (MAG) value. METHODS: This study involved 60 patients with severe aortic stenosis and EF < or =35%. Patients with coronary artery disease, more than moderate aortic regurgitation and any other valvular lesion were excluded. Patients were divided into two groups based on the MAG values: group I included patients with MAG < or =35 mmHg, and group II included patients with MAG >35 mmHg. RESULTS: Early mortality after aortic valve replacement was 14.2% in group I, and 5.1% in group II. During a mean follow-up of 48 months mortality in groups I and II was 16.6% and 2.6%, respectively. In the follow-up period, a significant functional improvement according to NYHA scale as well as significant decrease of left ventricular dimensions and increase of EF was observed in both groups of patients. CONCLUSIONS: Patients with severe aortic stenosis, left ventricular ejection fraction <35% and MAG < or =35 mmHg constitute a group of the highest early and long-term mortality risk after valve replacement. In turn, patients with MAG >35 mmHg should be classified as the group of slightly increased risk.     

Light stimulation evokes two different calcium responses in Müller glial cells of the guinea pig retina

Intracellular calcium responses are a characteristic of glial activation upon neuronal activity. In acutely isolated preparations of the guinea pig retina, Müller glial cells displayed cytosolic calcium rises in response to repetitive light stimulation. The calcium rises consisted of two components, a slowly developing immediate response that occurred simultaneously over the whole length of all Müller cell fibers and a delayed fast response that originated in the ganglion cell layer and spread as a wave through the bodies of some Müller cells toward the outer processes in the photoreceptor layer. The slow calcium response was evoked by photoreceptor-to-glia signaling, resulting in a glutamate transporter- and zinc-mediated alteration in the membrane potential and an influx of calcium from the extracellular space. The fast calcium response was evoked by a release of calcium from intracellular stores, probably after activation of purinergic receptors. The data suggest that light stimulation of the retina causes glial activation by alterations in both the membrane potential and receptor-mediated mechanisms. The former may be implicated in glial support of the neuronal signal transfer from photoreceptors to ganglion cells (glial forward signaling), whereas the latter may constitute a glial feedback signaling from ganglion cells to photoreceptors.     

A survey of prognostic value of serum factors in multiple myeloma patients before treatment: macrophage-colony stimulating factor (M-CSF) is a powerful predictor of survival

Cytokines are involved in the pathogenesis of multiple myeloma (MM) and other cancers. The aim of this study was to evaluate a range of cytokines of diverse activity in patients with multiple myeloma for a possible prognostic value. Concentrations of the following cytokines and cytokine receptors were measured by ELISA in the sera of 64 untreated MM patients: IL-6, IL-8, IL-10, TNFα, sTNF R I and II, sIL-2Rα, IL-1ra, M-CSF, G-CSF, VEGF, and bFGF. Serum levels of sTNF RI, IL-6, and bFGF were elevated in over 50% of patients. There was an inverse relationship between sTNF RII, TNFα, IL-1ra, and albumin levels. There was no significant relationship between cytokines/cytokine receptors and other serum correlates of myeloma. In a univariate survival analysis, β2-microglobulin, LDH, sIL-2Rα, sTNF RI, and M-CSF were significant variables. In a multivariate analysis, only M-CSF and β2-microglobulin retained a significant influence on survival. Serum M-CSF may be considered another independent and clinically useful prognostic factor in multiple myeloma.     

A novel insight into aging: are there pluripotent very small embryonic-like stem cells (VSELs) in adult tissues overtime depleted in an Igf-1-dependent manner?

Tissue and organ rejuvenation and senescence/aging are closely related to the function of stem cells. Recently, we demonstrated that a population of pluripotent Oct-4+ SSEA-1+Sca-1+Lin-CD45- very small embryonic-like stem cells (VSELs) resides in the adult murine bone marrow (BM) and other murine tissues. We hypothesize that these pluripotent stem cells play an important role in tissue/organ rejuvenation, and have demonstrated that their proliferation and potentially premature depletion is negatively controlled by epigenetic changes of some imprinted genes that regulate insulin factor signaling (Igf2-H19 locus, Igf2R and RasGRF1). Since the attenuation of insulin/insulin growth factor (Ins/Igf) signaling positively correlates with longevity, we propose, based on our experimental data, that gradual decrease in the number of VSELs deposited in adult tissues, which occurs throughout life in an Ins/Igf signaling-dependent manner is an important mechanism of aging. In contrast, a decrease in Ins/Igf stimulation of VSELs that extends the half life of these cells in adult organs would have a beneficial effect on life span. Our preliminary data in long-living Igf-1-signaling-deficient mice show that these animals possess a 3-4 times higher number of VSELs deposited in adult BM, lending support to this novel hypothesis.