Phagocytosis and cellular metabolism

Summary The uptake of foreign particles by mouse and human macrophages influenced by various metabolic inhibitors was examined in order to obtain further informations about the energy-dependent mechanisms which are involved in the phagocytic process. The inhibitors employed were iodoacetate, fluoroacetate, fluoride, malonate, sodium azide, 2-4-dinitrophenol, cycloheximide and ouabain. These substances were rested on monolayer cultures and the phagocytosis assay was performed by using zymosan suspension in the nutrient media. The quantitation of phagocytosis was obtained by the direct count of intracellular zymosan particles (immersion microscopy, 100x) and the results were evaluated and compared by biometrical analysis. The effects of these inhibitors on phagocytosis and their relation with the metabolic intracellular pathways are discussed.     

Changes in serum fetuin-A and inflammatory markers levels in end-stage renal disease (ESRD): effect of a single session haemodialysis.

BACKGROUND: The aim of the present study was to evaluate the effect of a single haemodialysis (HD) session on serum fetuin-A levels, considered a negative acute phase response marker; moreover, we evaluated the behaviour of fibrinogen and high sensitivity C-reactive protein (hsCRP) as acute phase response and chronic/subclinical inflammation markers, respectively, after a single HD session. METHODS: Serum fetuin-A, albumin, hsCRP and fibrinogen were measured in 72 patients before and after a single HD session. RESULTS: After a single HD session, we observed a significant increase in fibrinogen levels, while fetuin-A levels decreased (p<0.05). Also, hsCRP levels were significantly increased. CONCLUSIONS: The significant decrease of fetuin-A levels after a single HD session is consistent with the hypothesis of HD-induced inflammation; activated acute phase response and fetuin-A deficiency might account for increased cardiovascular risk and accelerated atherogenesis in dialysis patients.     

A human immunodeficiency virus type 1 pol gene-derived sequence (cPPT/CTS) increases the efficiency of transduction of human nondividing monocytes and T lymphocytes by lentiviral vectors

We have investigated the capacity of two human immunodeficiency virus type 1-derived lentivectors, differing in the presence of a 118-bp pol fragment containing the cPPT/CTS element, to transduce human normal primary cells of different hematopoietic lineages. Infection of resting monocytes with a high multiplicity of infection (MOI > 10) revealed that the lentivirus carrying the pol fragment (cPPT) is effective, transducing 75% of cells compared with 36% for the no-cPPT vector. Even at low MOIs (< or =1) the cPPT vector still shows a better transduction efficiency than the no-cPPT vector. Moreover, transduction does not require dendritic cell differentiation. In contrast, infection of nonactivated T lymphocytes showed that both vectors, tested at high MOIs, can transduce a small, although measurable, percentage of cells (up to 10%), which may correspond to G(1a) "activated" cells as detected by simultaneous staining of DNA and RNA, in our cultures in the presence of medium alone. Furthermore, we show that the sole addition of interleukin 2 or interleukin 15 represents a full proliferative signal under our conditions and permits high transduction efficiency (up to 30% with the cPPT vector and 15% with the no-cPPT vector). Still higher transduction of T lymphocytes can be achieved after stimulation with phytohemagglutinin and interleukin 2 (up to 78% with the cPPT vector vs. 42% with the no-cPPT vector). Finally, both viruses do not transduce either resting or proliferating tonsillar B lymphocytes.     

Low Rate of Intrahospital Deep Venous Thrombosis in Acutely Ill Medical Patients: Results From the AURELIO Study

Objective

To evaluate the effect of hospitalization on deep venous thrombosis (DVT) rate by the cumulative incidence of DVT in the proximal venous tract of the lower limbs at admission and discharge.

Involvement of the gp130 cytokine transducer in MtT/S pituitary somatotroph tumour development in an autocrine-paracrine model

OBJECTIVE: gp130 cytokines are placed as auto-paracrine regulators of pituitary function, since they, as well as their receptors, have been shown to be expressed in and to act in normal and tumoral anterior pituitary cells. The objective of this work was to study their involvement in a model that shows the interaction between different cellular types that participate in a tumorigenic process. DESIGN: The dependence of a pituitary somatotrophic cell line (MtT/S) on a gp130 cytokine-producing folliculostellate (FS) cell line (TtT/GF) for tumorigenesis in vivo has been described. In order to study the participation of gp130 cytokines in the auto-paracrine stimulation of MtT/S growth, we generated MtT/S gp130 sense (gp130-S) and gp130 antisense (gp130-AS) clones stably transfected with pcDNA3/gp130 sense and pcDNA3/gp130 antisense vectors respectively. METHODS AND RESULTS: Functional characterization studies revealed that gp130-AS clones have an inhibited gp130 signalling, and proliferation studies showed that they have an impaired response to gp130 cytokines but respond normally to other independent stimuli. When injected into nude mice, MtT/S clones respond differently depending on cell number; at high concentrations MtT/S clones alone generated tumours equivalent in size to tumours derived from MtT/S plus TtT/GF cells. At low concentrations, MtT/S sense and control clones generated tumours of smaller size than tumours derived from these same clones plus TtT/GF cells, showing a dependence on FS cells. In both cases MtT/S gp130-AS clones had impaired tumour development. Furthermore, vessel density was significantly lower in tumours derived from gp130-AS plus TtT/GF cells. CONCLUSIONS: This study underlines the importance of gp130 cytokines in proliferation and establishes its role in auto-paracrine pituitary growth regulation.     

Somatostatin analogs in vitro effects in a growth hormone-releasing hormone-secreting bronchial carcinoid

A 29-yr-old woman presented with acromegaly, pituitary gland enlargement, and an isolated pulmonary mass of 3.3 cm in diameter, which displayed a very high tracer uptake after OctreoScan. Plasma GHRH levels were markedly elevated. The patient underwent left lung upper lobectomy, and histopathology disclosed a bronchial atypical carcinoid. The tissue was examined for somatostatin (SRIH) receptor subtypes (SSTRs) 1-5 expression by RT-PCR. Cultured tumor cells were treated with SRIH, lanreotide (BIM-23014), or SRIH analogs selective for SSTR2 (BIM-23120), SSTR5 (BIM-23206), or SSTR1 (BIM-23926). GHRH was measured in the medium after 6 h, and cell viability was assessed after 48 h. RT-PCR analysis showed expression of SSTR1, -2, and -5. GHRH secretion was significantly reduced by SRIH (-50%), Lan (-35%), as well as by the SSTR2, SSTR5, and SSTR1 selective agonists (-55, -75, and -20%, respectively), whereas cell viability was not affected. Our data show SSTR expression in a GHRH-secreting bronchial carcinoid and provide evidence that, in vitro, selective SSTR activation differently inhibit ectopic GHRH secretion. These findings suggest that SSTR-specific SRIH analogs may be useful in the medical therapy of GHRH-secreting bronchial carcinoids.     

Effect of proton pump inhibitors and antacid therapy on 13C urea breath tests and stool test for Helicobacter pylori infection

OBJECTIVE: There is uncertainty about the best method of testing patients for Helicobacter pylori (H. pylori) infection while they are taking proton pump inhibitors. The aim of this study was to determine: (i) if the decreased sensitivity of the urea breath test during proton pump inhibitor is corrected by different techniques for breath testing and (ii) if the sensitivity of stool test is decreased with the administration of proton pump inhibitors. METHODS: Prospective randomized single-blind study was performed in a tertiary care university hospital. Out of 72 H. pylori infected patients endoscoped for upper abdominal symptoms 48 were randomized to proton pump inhibitors (omeprazole 20 mg each day or esomeprazole 40 mg each day) and 24 to antacid (aluminum hydroxide 800 mg each day) for 14 days. Several breath tests (standard 75 mg (13)C-UBT with citric acid, with orange juice, a tablet breath test with 100 and 50 mg of (13)C), and a stool test were carried out. Baseline samples were collected before and after treatment. RESULTS: The baseline sensitivity for all breath tests was 100% in both groups; for stool test it was 97.8% (95% CI: 88.7-96.6) and 90% (95% CI: 69.9-97.2) in the proton pump inhibitor and antacid group, respectively. After treatment, the sensitivity of tests was significantly low (UBTs range: 77.1%-85.4%; stool test: 83%; 95% CI: 63.9-91.1), while it was unchanged in the antacid group. CONCLUSIONS: False negative breath and stool tests are equally common in patients taking proton pump inhibitors. Antacids do not impair the sensitivity of the breath tests or the stool test.