Heat-induced reduction of deoxynivalenol and its modified forms during flaking and cooking of oat

Deoxynivalenol (DON) and its modified forms deoxynivalenol-3-glucoside (DON-3G) and 3-acetyl-deoxynivalenol (3-ADON) are common contaminants in Norwegian oats. In order to provide more information about the fate of these mycotoxins during oat processing, the levels of DON, DON-3G, 3-ADON and the sum of them (total DON) were determined using LC-HRMS/MS at different processing steps. Oat groat was softened by either steaming or conditioning, rolled into flakes of two thicknesses, and subsequently cooked to produce flake porridges. Flour of oat groat (untreated or kilned) was cooked to flour porridges. The flaking process had major effect on the mycotoxin levels in resulting flakes, with significant impact for type of softening regime, but not for flake size. Steam-softening caused the largest reduction of DON, DON-3G and total DON in flakes, retaining 41, 60 and 46%, respectively, compared to oat groat. In contrast, 3-ADON in flakes was most reduced by conditioning, to 29% of the levels in oat groat. Cooking to porridge from flakes did not result in any additional mycotoxin reduction, though significant impact of flake size was shown in the final porridges, with highest reduction of total DON in the porridges originating from steamed thick flakes. Cooking porridge from untreated oat flour gave significant reduction in mycotoxin levels, however not for kilned oat flour which had already undergone reduction during kilning. In conclusion, the study shows that processes involving heat-treatment, i.e. kilning, steaming or cooking, efficiently reduced total DON in oats during flaking and porridge cooking, and reduction is dependent on previous processing steps.

AB0291 RITUXIMAB MAY DELAY THE MOVEMENT OF RHEUMATOID ARTHRITIS PATIENTS ON CARDIORENAL CONTINUUM: RESULTS FROM A PROSPECTIVE OBSERVATIONAL SINGLE-CENTRE COHORT STUDY

Background:

Similarities in risk factors, initial stages, progression and final stage of both atherosclerotic cardiovascular disease (ACVD) and chronic kidney disease (CKD) allowed formulating a concept of cardiorenal continuum.1ACVD and CKD remain the main causes of mortality in rheumatoid arthritis (RA) patients.2,3

Objectives:

To evaluate the effects of rituximab (RTM) therapy on cardiorenal continuum of RA patients.

Methods:

Biologics-naïve RA patients (n=92; age 49.5±9.9) were followed up for 72 months after commencing and continuing RTM therapy (1–10 standard courses) compared with 50 control RA patients (age 49.2±9.8). All control and 63% of RTM patients received methotrexate or leflunomide.

Results:

There were no baseline differences between two groups – Table. At year 6, RTM patients have fewer incidences of hypertension, anxiety/depression, atherosclerosis and diastolic dysfunction than controls. RTM decreased prevalence of albuminuria and CKD.

Table.

Cardiorenal continuum of rheumatoid arthritis patients (%)

FeaturesRituximab groupControl grouppRTM–C1 year n=923 years n=476 years n=311 yearn=503 years n=266 years n=16Risk factorsHypertension52.238.325.8p6–1=0.02250.038.550.0p6=0.032Dyslipidaemia44.636.238.748.046.250.0>0.05Pre-diabetes41.336.241.944.034.656.3>0.05Metabolic syndrome12.06.43.210.07.712.5>0.05Diabetes mellitus3.2002.000>0.05Anxiety/depression78.341.5p3–1=0.00535.3p6–1<0.00176.073.168.8p3=0.009p6=0.008Initial stages (asymptomatic organ damage)Atherosclerosis34.821.312.9p6–1=0.04536.034.637.5p6=0.02Left ventricular hypertrophy8.74.308.07.70>0.05Diastolic dysfunction57.638.322.6p6–1=0.01856.050.056.3p6=0.04Albuminuria19.600p6–1=0.03812.006.3>0.05Kidney impairment6.52.106.000>0.05ProgressionAngina6.5004.000>0.05Chronic kidney disease26.18.59.7p6–1=0.04212.000>0.05End stageMyocardial infarction000000>0.05Stroke000000>0.05Heart failure4.400000>0.05Acute/chronic renal failure000000>0.05Death000000>0.05

There were no significant differences in frequencies of other risk factors, signs of organ damage and cases of established heart, cerebrovascular and renal diseases/complications.

Conclusion:

RTM may be effective in delay of the movement of RA patients on cardiorenal continuum. The clinical implications of RTM for cardiorenal correlations in RA patients need to be confirmed in large-scale clinical outcome trials.

References:

[1]Sarnak MJ, Levey AS. Cardiovascular disease and chronic renal disease: a new paradigm.Am J Kidney Dis2000;35(4, Suppl. 1):117–31.

[2]Avina-Zubieta JA, Choi HK, Sadatsafarvi M,et al.Risk of cardiovascular mortality in patients with rheumatoid arthritis: a meta-analysis of observational studies.Arthritis Rheum2008;59:1690–7.

[3]Gullick NJ, Scott DL. Co-morbidities in established rheumatoid arthritis.Best Pract Res Clin Rheumatol2011;25:469–83.

Disclosure of Interests:

Ilshat Gaisin Speakers bureau: Boehringer Ingelheim, KRKA, Berlin-Chemie Menarini, Sanofi, Larisa Ivanova Speakers bureau: Bayer, Novartis, KRKA, Nikolay Maximov Speakers bureau: Pfizer, KRKA, Rosa Valeeva: None declared, Dilara Yurk: None declared, Anastasia Vedekhina: None declared, Nuriya Garaeva: None declared, Irina Sabelnikova: None declared

SAT0107 BIOLOGIC THERAPY WITH RITUXIMAB DECREASES PREVALENCE OF ANXIETY AND DEPRESSION IN RHEUMATOID ARTHRITIS PATIENTS

Background:

Evidence suggests rheumatoid arthritis (RA) confers an increased risk of psychological morbidity, particularly anxiety and depression, which may affect the subsequent management and treatment adherence.1,2Few studies have studied psychological factors over time in RA patients.3

Objectives:

To evaluate the prevalence of anxiety and depression in RA patients following rituximab treatment.

Methods:

92 biologics-naïve RA patients [mean (SD) age 49.5 (9.9) years, 78 women; median (IQR) DAS28 5.67 (3.94–8.45); median (IQR) HAQ 1.87 (1.2–3.5)] were followed up for 27 months after commencing and continuing rituximab therapy (1, 2, 3 standard courses). Anxiety and depression, and health-related quality of life (HRQoL) were assessed at baseline, 3, 15 and 27 months using the Hospital Anxiety and Depression Scale (HADS) and the Short Form (SF-36 v.1) Health Survey questionnaire, respectively.

Results:

Median anxiety and depression scores decreased significantly between baseline and 3 months and continued depress over the 27-month period – Table. The prevalence of depression cases decreased twice from baseline to 27 months (p<0.01), as did the prevalence of anxiety (p<0.01). Patients reported poor baseline HRQoL. SF-36 domain scores substantially rose after 15 and 27 months.

Anxiety, depression, and quality of lifeBaseline3 months15 months27 months(n=92)(n=92)(n=53)(n=14)Anxiety cases (HADS-A score ≥8), n (%)72 (78.3)48 (52.2)24 (45.3)*5 (35.7)**Median (IQR) Anxiety score12.6 (10–15)8.2 (5–12)*6.4 (3–10)**5.5 (3–8)***Depression cases (HADS-D score ≥8), n (%)62 (67.4)50 (54.3)19 (35.8)*4 (28.6)**Median (IQR) Depression score9.2 (7.8–9.6)5.6 (3–8)**4.5 (2–7)**3.6 (2–6)***Mean (SD) Mental Health score42.8 (15.2)51.2 (18.3)68.7 (11.2)*72.9 (10.5)**Mean (SD) Physical Function score24.4 (8.3)32.5 (9.8)53.8 (10.5)*54.5 (9.3)*Mean (SD) Social Function score48.2 (15.4)56.8 (25.5)59.8 (18.7)65.9 (9.2)*Mean (SD) General Health score35.8 (11.2)48.7 (10.8)67.8 (8.6)**75.9 (12.6)**

* p<0.05, ** p<0.01, *** p<0.001 differences between baseline and follow-up

Conclusion:

Anxiety and depression levels decrease significantly in RA patients following commencement and continuity of rituximab. B cell-directed therapy for patients with RA helps achieve remission of both anxiety and depression, and improves HRQoL.

References:

[1]McWilliams LA, Goodvin RD, Cox BJ. Depression and anxiety associated with three pain conditions: results from a nationally representative sample.Pain2004;111:77–83.

[2]Garcia-Cebrian A, Gandhi P, Demyttenaere K et al. The association of depression and painful physical symptoms: a review of the European literature.Eur Psychiatry2006;21:379–88.

[3]Overman CL, Bossema ER, van Middendorp H et al. The prospective association between psychological distress and disease activity in rheumatoid arthritis: a multilevel regression analysis.Ann Rheum Dis2012;71:192–7.

Disclosure of Interests:

Ilshat Gaisin Speakers bureau: Boehringer Ingelheim, KRKA, Berlin-Chemie Menarini, Sanofi, Larisa Ivanova Speakers bureau: Bayer, Novartis, KRKA, Nikolay Maximov Speakers bureau: Pfizer, KRKA, Anastasia Vedekhina: None declared, Dilara Yurk: None declared, Nuriya Garaeva: None declared

Effect of primary processing on the distribution of free and modified Fusarium mycotoxins in naturally contaminated oats

Oat (Avena sativa L.) ranks seventh in the world cereal production and is considered to be an important source for many valuable components of nutritional and biological importance, i.e. proteins, fats, carbohydrates, fibre, minerals and vitamins. Because of these properties the amount of oat used for human consumption has increased progressively during the last years. Unfortunately, the quality of this grain crop is often compromised by mycotoxin contamination, which is relatively ubiquitous despite efforts to control the problem. Therefore, it is important to investigate the distribution pattern of mycotoxins and their conjugated derivatives in contaminated oat grains. For this purpose we have developed a state-of-the-art multi-mycotoxin high-resolution mass spectrometry method and analysed oat samples for their content of the most important mycotoxins commonly occurring in Norwegian cereal grain. Quantitative mapping of selected Fusarium free and modified mycotoxins was performed in fractions collected during processing trials consisting of dehulling and sequential pearling. Both the derivative free mycotoxins and their metabolites were mainly present in the hulls compared to the oat kernel, thus dehulling resulted in a significant reduction of the total mycotoxin load, followed by some further reduction by pearling. Furthermore, free and modified mycotoxins were unevenly distributed in relation to each other throughout the grain fractions, showing a shift towards glucosidated forms, such as deoxynivalenol-3-glucoside and HT-2-3-glucoside in the oat kernel, which highlights potential food safety concerns associated with in planta modified mycotoxins.

Chronic Liver Diseases and Parenterally Transmitted Hepatitis Viruses

Hepatitis B virus (HBV), hepatitis C virus (HCV) and hepatitis D virus (HDV) are the leading cause of chronic liver diseases. The aims of the present study are to determine the etiological relationship of HBV and HCV in patients with chronic liver disease in North-Eastern Bulgaria and prevalence of dual and triple infections. A total of 434 patients were investigated for HBsAg, 402 of whom were also tested for anti-HCV. The HBsAg positive subjects were tested for anti-HDV and 32 of them also for HbeAg/anti-Hbe. Separated commercial ELISA kits were used. HBsAg was detected in 132 (30.4%); 10.6% were co-infected with HDV. Anti-HCV was detected in 15.4%. Five of 132 HbsAg positive patients (3.78%) were simultaneously HBV and HCV positive. Two patients out of 132 (1.52%) were positive to HBV, HCV and HDV. Our data indicate that HBV infection was the main cause of chronic liver diseases in North-Eastern Bulgaria, and 10.6% of the patients suffered from severe disease because of co-infection with HDV. HCV plays the same role in 15.4% of the cases. Recently, we observed dually infected (HBV and HCV) and triple infected (HBV, HCV, HDV) patients suffering from severe chronic liver diseases.

Prognostic relevance of carbonic anhydrase IX expression is distinct in various subtypes of breast cancer and its silencing suppresses self-renewal capacity of breast cancer cells

PURPOSE

Carbonic anhydrase IX (CAIX) is a hypoxia-inducible enzyme with extracellular catalytic domain that is overexpressed in a variety of cancers including breast cancer and plays a crucial role in maintaining favourable intracellular pH and reducing extracellular pH. The purpose of the current study was to elucidate the prognostic significance of CAIX in the intrinsic subtypes of breast cancer and to characterise CAIX as a drug target in breast cancer.

METHODS

The prognostic significance of CAIX mRNA expression was interrogated in a cohort of 3,455 breast tumours by using an online tool, Kaplan-Meier plotter. The functional effects of stable CAIX depletion by shRNA in three breast cancer cell lines—MDA-MB-231, MCF7 and SKBR-3, representing basal-like, luminal A and HER2+ subtypes, respectively—were studied by proliferation, invasion, clonal spheroid formation and chemosensitivity assays under normoxia and hypoxia. Finally, the effect of pharmacological CA inhibition alone or in the combination with doxorubicin on self-renewal was assessed by spheroid-forming assay.

RESULTS

High CAIX mRNA expression was significantly associated with poor survival in patients with basal-like, luminal B and triple-negative breast cancer, but not luminal A and HER+ subtypes. Silencing of CAIX expression had no significant effect on the cell proliferation or viability upon treatment with doxorubicin in any of the cell lines studied, while it inhibited spheroid formation in hypoxic conditions. Furthermore, pharmacological inhibition of CAs using acetazolamide had a synergistic effect with doxorubicin on decreasing the spheroid-forming efficiency in MDA-MB-231 cells.

CONCLUSIONS

Inhibition of CAIX reduces the self-renewal capacity of breast cancer cells, and the combination of doxorubicin and CAIX inhibition is an attractive therapeutic strategy in basal-like and triple-negative breast cancer, which warrants further investigations.

Presence of enniatin B and its hepatic metabolites in plasma and liver samples from broilers and eggs from laying hens

Enniatins, a large group of cyclodepsipeptides, are widely distributed contaminants of different crops intended for human and animal consumption. Enniatin B is one of the principal analogues in species of the genus Fusarium, known to have ionophoric, antibiotic, and insecticidal activity. Regardless of considerable cytotoxic effects observed in vitro, enniatins have been characterised as compounds with low acute toxicity in vivo. The biotransformation of enniatin B has previously been elucidated in liver microsomes, and 12 different metabolites (M1 to M12) have been reported. In order to provide a better basis for understanding the potential toxic effects in humans and animals, different samples (eggs, livers, plasma) from two different feeding studies have been analysed for the presence of enniatin B and its hepatic metabolites. The earlier reported metabolite M11, and a novel metabolite (designated M13), were dominant in liver samples from enniatin B exposed broilers. The peak area corresponding to the sodiated molecular ion of M11 was approximately 2.5 times larger than that of parent enniatin B in liver samples collected after one week of exposure. The same metabolites were also present in serum samples. In egg samples, only metabolites M13 and M4 were detected. The comparison of mass spectrometric data of M13 and enniatin B suggested that M13 is a monohydroxylated metabolite. The hepatic biotransformation of enniatin B was also investigated in vitro in chicken microsomes demonstrating good correlation with the metabolite profiles in the chicken samples. The results of the present study demonstrated an extensive biotransformation of enniatin B in vivo confirming previously reported in vitro data.

Serologic Hepatitis B Virus Immunity in Health Care Workers

Health care workers (HCWs) are at high risk of blood borne infections including Hepatitis B virus (HBV) infection. HBV vaccination is recommended for HCWs but post vaccination testing of immune response (anti-HBs) is not routinely performed. In our study information on immune response after the first immunization schedule of HCWs is not available. By reason of the questions regarding long lasting immunity, we decided to assess the anti-HBs of HCWs who wished to check immune response after different times of vaccination and also unvaccinated persons in St. Marina University Hospital, Varna, Bulgaria. After informed consent, 341 HCWs were investigated. They were divided into 3 groups according to their status: Group A had no history of vaccination against HBV, Group B had no complete vaccination schedule and Group C had complete vaccination data. Of Group C, 32 had been vaccinated more than 10 years previously, 111 - 10–5 years previously and 48 - < 5 years previously. Quantitative detection of antibody to HBsAg (anti-HBs) by commercial ELISA was carried out. A total, positive immune response was detected in 35.6% (group A), 66.2% (group B) and 80.1% (group C) of HCWs investigated. Of Group C positive immune response was detected in 68.7%, 81.1% and 85.4% respectively of the time of vaccination. Detectable anti-HB was found in HCWs without HBV immunization, probably after unknown exposure to HBV. The lack of information regarding immune response after the first immunization schedule makes the interpretation of no detectible anti-HBs level 5–10 years post-immunization difficult. For the HCWs with anti-HBs loss, counseling for booster vaccine dose and consequent testing is mandatory.

Lysosomes as a possible target of enniatin B-induced toxicity in Caco-2 cells

Enniatins are cyclic hexadepsipeptidic mycotoxins with ionophoric, antibiotic, and insecticidal activity. Enniatin B (EnnB), the most important analogue, is produced by many Fusarium species and is a common contaminant in grain-based foods. The compound's cytotoxic potential has been shown in different experiments; however, the mode of action has not been detailed so far. In the present study, several mutually confirmative experiments have been performed indicating that EnnB-initiated cytotoxicity could be connected with lysosomal membrane permeabilization (LMP). Lysosomal functionality, as assessed by the Neutral Red assay, was already affected after 3 h of toxin exposure. After 24 h, cell proliferation was decreased, and there was indication for a cell cycle arrest in the G(2)/M phase leading to the initiation of apoptosis or necrosis. Intracellular ROS-production was observed. However, antioxidants did not alter the observed EnnB-induced loss of lysosomal functionality leading to the conclusion that ROS was not an initial factor but one produced later in the event cascade. The collected data suggested that lysosomal destabilization is an upstream event in EnnB-initiated cytotoxicity followed by a certain extent of translocation of cathepsins into the cytosol, which was observed using immunological and proteomic methods. It appeared that cell death induced by EnnB was delayed and occurred not as a massive lysosomal breakdown but was probably progressing and leading to partial and selective LMP, starting a nonapoptotic cell death pathway with morphological features that had been previously considered as necrotic. The molecular mechanism of EnnB-triggered lysosomal destabilization, and the cellular processes leading to mitochondrial permeabilization and cell death are still unknown. They may, however, be connected to the compound's ionophoric properties.

Tumor-associated autoantibody signature for the early detection of gastric cancer

Autoantibodies against tumor-associated antigens are very attractive biomarkers for the development of noninvasive serological tests for the early detection of cancer because of their specificity and stability in the sera. In our study, we applied T7 phage display-based serological analysis of recombinant cDNA expression libraries technique to identify a representative set of antigens eliciting humoral responses in patients with gastric cancer (GC), produced phage-antigen microarrays and exploited them for the survey of autoantibody repertoire in patients with GC and inflammatory diseases. We developed procedures for data normalization and cutoff determination to define sero-positive signals and ranked them by the signal intensity and frequency of reactivity. To identify autoantibodies with the highest diagnostic value, a 1,150-feature microarray was tested with sera from 100 patients with GC and 100 cancer-free controls, and then the top-ranked 86 antigens were used for the production of focused array that was tested with an independent validation set comprising serum samples from 235 patients with GC, 154 patients with peptic ulcer and gastritis and 213 healthy controls. The receiver operating characteristic curve analysis showed that 45-autoantibody signature could discriminate GC and healthy controls with area under the curve (AUC) of 0.79 (59% sensitivity and 90% specificity), GC and peptic ulcer with AUC of 0.76 and GC and gastritis with AUC of 0.64. Moreover, it could detect early GC with equal sensitivity than advanced GC. Interestingly, the autoantibody production did not correlate with histological type, H. pylori status, grade, localization and size of the primary tumor, whereas it appeared to be associated with the metastatic disease.

Enniatin B1 is a substrate of intestinal P-glycoprotein, multidrug resistance-associated protein 2 and breast cancer resistance protein

Enniatins are cyclic hexadepsipeptides produced by various fungi, known to have ionophoric, antibiotic and insecticidal activity. The aim of the present study was to evaluate the intestinal absorption characteristics of enniatin B1 (ENN-B1). Using the human intestinal Caco-2 cell line, we found that the permeability of ENN-B1 in the basolateral to apical direction was 6.7× higher as compared to the permeability in the opposite direction, indicating involvement of apically located transporters. Transport of ENN-B1 in the apical to basolateral direction was increased significantly upon treatment of Caco-2 cells with the P-glycoprotein (Pgp) inhibitor verapamil and the multidrug resistance-associated protein 2 (MRP2) inhibitor MK571, but only weakly and not significantly after treatment with the breast cancer resistance protein (BCRP) inhibitor fumitremorgin C. Additionally, MDCK II cells over-expressing Pgp, MRP2 or BCRP, showed reduced sensitivity towards ENN-B1. These data demonstrate for the first time that ENN-B1 is a substrate of MRP2 and suggests that Pgp, MRP2 and possibly BCRP are involved in transport of ENN-B1 across the intestine.

Prognostic significance of hepatocyte growth factor and microvessel bone marrow density in patients with chronic myeloid leukaemia

OBJECTIVE

The aims of the study were: (1) to perform a complex angiogenic assessment in chronic myeloid leukaemia (CML) patients using multiple parameters: bone marrow microvessel density (MVD), bone marrow immunohistochemical cellular expressions of vascular endothelial growth factor (VEGF) and its receptor KDR, as well as hepatocyte growth factor (HGF) and its receptor MET, and the plasma VEGF and HGF; and (2) to determine the clinical significance of these factors for patients with CML.

MATERIAL AND METHODS

The VEGF and HGF plasma levels were analysed by ELISA in 38 newly diagnosed CML patients. Immunohistochemical methods were used to visualize the MVD as well as the cellular VEGF/KDR and HGF/MET expression.

RESULTS

We found an increased MVD, cellular VEGF/KDR and HGF/MET expression and elevated plasma VEGF and HGF in CML patients. The plasma HGF, cellular HGF and MET expression correlated with the CML phase. The plasma HGF correlated with all markers reflecting the tumour burden (leucocytes, blast percentage, splenomegaly and LDH) as well as with the phase of CML and overall survival of the patients. Cox regression analysis determined the prognostic relevance of HGF and MVD parameters, but not for the plasma VEGF and cellular VEGF and KDR.

CONCLUSIONS

Using a complex angiogenic assessment we determined an increased angiogenesis in CML patients. No prognostic relevance was found for VEGF plasma levels or VEGF/KDR cellular bone marrow expression. The increased cellular HGF and MET expressions could be considered high-risk factors for these patients. Plasma HGF and MVD were shown to be independent prognostic parameters for patients' survival.

Self-organized formation of GaSb/GaAs quantum rings

Ring-shaped GaSb/GaAs quantum dots, grown by molecular beam epitaxy, were studied using cross-sectional scanning tunneling microscopy. These quantum rings have an outer shape of a truncated pyramid with baselengths around 15 nm and heights of about 2 nm but are characterized by a clear central opening extending over about 40% of the outer baselength. They form spontaneously during the growth and subsequent continuous capping of GaSb/GaAs quantum dots due to the large strain and substantial As-for-Sb exchange reactions leading to strong Sb segregation.

2-Amino-14,16-dimethyloctadecan-3-ol: in vitro bioactivity and bio-production by the fungus Fusarium avenaceum

2-Amino-14,16-dimethyloctadecan-3-ol (2-AOD-3-ol) belongs to the class of sphingosine analogue toxins, which is a class of toxins that is known among several fungal genera and some lower marine animals. Many sphingosine analogues have been shown to inhibit ceramide synthase through structural similarities with the substrates of the enzyme. The adverse effects of some analogues, e.g. the fumonisins, are a result of ceramide synthase inhibition. The primary aim of this work was to generate basic knowledge on the toxicity of 2-AOD-3-ol in vitro. The human hepatocarcinoma cell line Hep G2 and horse erythrocytes were used in order to achieve this aim. The second aim of this work was to gain insight into the capabilities of the fungus Fusarium avenaceum, a common contaminant of grain in Scandinavia, to produce the toxin under laboratory conditions on different grain species, and in the field. The metabolite was found to be cytotoxic in several assays (lower µM-range) that measure general cytotoxicity (Alamar Blue" assay, Neutral Red uptake, LDH leakage), but did not inhibit ceramide synthase as measured by the increase of the sphinganine/sphingosine ratio. The cellular membrane was likewise not found to be a primary target of the molecule. Strains of F. avenaceum produced up to 6.3 mg/g of 2-AOD-3-ol on wheat grain under controlled conditions in the laboratory, while only low amounts (<56 µg/kg) could be found in field samples.

Effect of an increase in brain serotonin on the osmoregulatory response to a hypo- or hyperosmotic load in Wistar and vasopressin-deficient Brattleboro rats

Serotonin and its receptor agonists stimulate the release of arginine vasopressin (AVP) into peripheral blood under intraventricular injection. To test the hypothesis that brain serotonin can modulate the development of natural osmoregulatory responses, the effect of an increase in endogenous brain serotonin on the response to an intragastric hypo- or hyperosmotic loading was studied in Wistar and AVP-deficient Brattleboro rats. 5-Hydroxytryptophan (5-HTP), the rate-limiting serotonin biosynthesis precursor known to increase the brain level of serotonin, was injected intraperitoneally (5 mg/100 g body weight). The renal functional parameters (glomerular filtration rate [GFR], free water reabsorption, and urine flow rate) were monitored during the 4 h after intragastric infusion of water or a 2% NaCl solution (5% of body weight). Plasma AVP was measured by radioimmunoassay. In Wistar rats, intraperitoneal injection of 5-HTP at the same time as water loading prevented the development of the renal diuretic response: there was no increase in urine flow rate and GFR, and free water reabsorption remained at the high level. In AVP-deficient Brattleboro rats, unlike Wistar rats, 5-HTP treatment was without effect on the renal function parameters. In Wistar rats, injection of 5-HTP at the peak of water diuresis produced an abrogation of the diuretic response to water loading due to the increase in free water reabsorption. Plasma AVP increased from 1.2 +/- 0.4 to 4.2 +/- 1.6 pg/ml (n = 8 in each group, p < 0.01). Hyperosmotic treatment of Wistar rats with a 2% NaCl solution stimulated AVP secretion compared to baseline (from 3.2 +/- 0.1, n = 7 to 5.6 +/- 0.9, n = 7, p < 0.01), and the saluretic response developed on the background of high free water reabsorption. When injected concomitantly with NaCl solution, 5-HTP revealed no additive effect on plasma AVP and on free water reabsorption. We conclude that the 5-HTP-caused increase in brain serotonin contributed significantly to the dynamics of changes in the osmoregulatory response to the hypo-osmotic challenge due to stimulation of AVP secretion. 5-HTP had no additive effect on the osmoregulatory response to hyperosmotic loading. Peripherally injected 5-HTP had no effect on the renal function, being absent in AVP-deficient Brattleboro rats.

Influence of membrane phospholipid composition and structural organization on spontaneous lipid transfer between membranes

Investigations were carried out on the influence of phospholipid composition of model membranes on the processes of spontaneous lipid transfer between membranes. Acceptor vesicles were prepared from phospholipids extracted from plasma membranes of control and ras-transformed fibroblasts. Acceptor model membranes with manipulated levels of phosphatidylethanolamine (PE), sphingomyelin and phosphatidic acid were also used in the studies. Donor vesicles were prepared of phosphatidylcholine (PC) and contained two fluorescent lipid analogues, NBD-PC and N-Rh-PE, at a self-quenching concentration. Lipid transfer rate was assessed by measuring the increase of fluorescence in acceptor membranes due to transfer of fluorescent lipid analogues from quenched donor to unquenched acceptor vesicles. The results showed that spontaneous NBD-PC transfer increased upon fluidization of acceptor vesicles. In addition, elevation of PE concentration in model membranes was also accompanied by an increase of lipid transfer to all series of acceptor vesicles. The results are discussed with respect to the role of lipid composition and structural order of cellular plasma membranes in the processes of spontaneous lipid exchange between membrane bilayers.

Ribin, a protein encoded by a message complementary to rRNA, modulates ribosomal transcription and cell proliferation

The control of rRNA transcription, tightly coupled to the cell cycle and growth state of the cell, is a key process for understanding the mechanisms that drive cell proliferation. Here we describe a novel protein, ribin, found in rodents, that binds to the rRNA promoter and stimulates its activity. The protein also interacts with the basal rRNA transcription factor UBF. The open reading frame encoding ribin is 96% complementary to a central region of the large rRNA. This demonstrates that ribosomal DNA-related sequences in higher eukaryotes can be expressed as protein-coding messages. Ribin contains two predicted nuclear localization sequence elements, and green fluorescent protein-ribin fusion proteins localize in the nucleus. Cell lines overexpressing ribin exhibit enhanced rRNA transcription and faster growth. Furthermore, these cells significantly overcome the suppression of rRNA synthesis caused by serum deprivation. On the other hand, the endogenous ribin level correlates positively with the amount of serum in the medium. The data show that ribin is a limiting stimulatory factor for rRNA synthesis in vivo and suggest its involvement in the pathway that adapts ribosomal transcription and cell proliferation to physiological changes.

Mutant prion proteins are partially retained in the endoplasmic reticulum

Familial prion diseases are linked to point and insertional mutations in the prion protein (PrP) gene that are presumed to favor conversion of the cellular isoform of PrP to the infectious isoform. In this report, we have investigated the subcellular localization of PrP molecules carrying pathogenic mutations using immunofluorescence staining, immunogold labeling, and PrP-green fluorescent protein chimeras. To facilitate visualization of the mutant proteins, we have utilized a novel Sindbis viral replicon engineered to produce high protein levels without cytopathology. We demonstrate that several different pathogenic mutations have a common effect on the trafficking of PrP, impairing delivery of the molecules to the cell surface and causing a portion of them to accumulate in the endoplasmic reticulum. These observations suggest that protein quality control in the endoplasmic reticulum may play an important role in prion diseases, as it does in some other inherited human disorders. Our experiments also show that chimeric PrP molecules with the sequence of green fluorescent protein inserted adjacent to the glycolipidation site are post-translationally modified and localized normally, thus documenting the utility of these constructs in cell biological studies of PrP.

Stimulated nonspecific transport of phospholipids results in elevated external appearance of phosphatidylserine in ras-transformed fibroblasts

The content of phosphatidylserine (PS) was found to be increased three times in the plasma membrane outer leaflet of ras-transformed fibroblasts compared to their nontransformed counterparts. In an attempt to determine the mechanisms responsible for the enhanced external appearance of PS, we investigated the activities of aminophospholipid translocase and the nonspecific lipid scramblase. Both transport systems could separately or in combination contribute to PS accumulation in the extracellular leaflet. Aminophospholipid transfer was assessed by measuring the rate of NBD-PS internalization, and scramblase activity was estimated from the internalization of NBD-PC. The results showed that the aminophospholipid transport was inhibited and the nonspecific transport was stimulated in ras-transformed cells. To assess which of these two transport systems was related to elevation of PS external appearance, each of them was submitted to reversible alterations and the content of PS was measured simultaneously. Aminophospholipid translocase activity was inhibited by pyridyldithioethylamine treatment and reversed by reduction with dithiothreitol. Scramblase activity was modulated by a calcium repletion-depletion procedure. Calcium depletion was performed by cell incubation with BAPTA-AM and EGTA as Ca2+ intracellular and extracellular chelators. Restoration of the intracellular Ca2+ was achieved by cell incubation with Ca2+ and Ca2+-ionophore A23187. The results showed that the changes in PS outer appearance did not correlate with the uptake of NBD-PS but were closely related to NBD-PC internalization, suggesting that the nonspecific bidirectional lipid transfer was the major transport system translocating PS to the outer leaflet in ras-transformed cells.

Regulated expression of a Sindbis virus replicon by herpesvirus promoters

We describe the use of herpesvirus promoters to regulate the expression of a Sindbis virus replicon (SINrep/LacZ). We isolated cell lines that contain the cDNA of SINrep/LacZ under the control of a promoter from a herpesvirus early gene which requires regulatory proteins encoded by immediate-early genes for expression. Wild-type Sindbis virus and replicons derived from this virus cause death of most vertebrate cells, but the cells discussed here grew normally and expressed the replicon and beta-galactosidase only after infection with a herpesvirus. Vero cell lines in which the expression of SINrep/LacZ was regulated by the herpes simplex virus type 1 (HSV-1) infected-cell protein 8 promoter were generated. One Vero cell line (V3-45N) contained, in addition to the SINrep/LacZ cDNA, a Sindbis virus-defective helper cDNA which provides the structural proteins for packaging the replicon. Infection of V3-45N cells with HSV-1 resulted in the production of packaged SINrep/LacZ replicons. HSV-1 induction of the Sindbis virus replicon and packaging and spread of the replicon led to enhanced expression of the reporter gene, suggesting that this type of cell could be used to develop sensitive assays to detect herpesviruses. We also isolated a mink lung cell line that was transformed with SINrep/LacZ cDNA under the control of the promoter from the human cytomegalovirus (HCMV) early gene UL45. HCMV carries out an abortive infection in mink lung cells, but it was able to induce the SINrep/LacZ replicon. These results, and those obtained with an HSV-1 mutant, demonstrate that this type of signal amplification system could be valuable for detecting herpesviruses for which a permissive cell culture system is not available.

In vivo linearization and autonomous replication of plasmids containing human telomeric DNA in Aspergillus nidulans

Plasmids containing two inverted 0.6-kb stretches of human telomeric repeats transform Aspergillus nidulans at frequencies characteristic of autonomously replicating vectors. Transformation frequency is not affected when the plasmids are linearized in vitro prior to transformation by cutting between the inverted repeats. Southern analysis reveals the presence of a homogeneous pool of linear plasmid molecules in mycelium of transformants. Addition of the AMA1 plasmid replicator to the telomere-containing plasmids has only a minor effect on transformation. The phenotypic stability of the transformants is low. However, unlike conventional replicative transformants containing AMA1-bearing plasmids, these transformants are prone to spontaneous stabilization which occurs predominantly by conversion of the mutant chromosomal allele of the marker gene to the plasmid-borne allele. The data strongly suggest that telomeric DNA can act as a plasmid replicator. An alternative interpretation is that autonomous replication of linear DNA fragments, in contrast to covalently closed supercoiled molecules, does not require any special replicator sequences.

Effects of site-directed mutations of transmembrane cysteines in sindbis virus E1 and E2 glycoproteins on palmitylation and virus replication

The two glycoproteins that form the external spikes of the alphaviruses are type 1 membrane proteins whose transmembrane domains of hydrophobic amino acids are close to the carboxyl termini of the polypeptides and anchor the proteins in the lipid bilayer. Most of the members of the alphavirus genus contain within this transmembrane sequence one or more highly conserved cysteines, which are positioned close to the cytoplasmic face of the lipid bilayer. Cysteines in the cytoplasmic domains of the alphavirus glycoproteins and other enveloped viruses have been shown to be modified by palmitylation. To determine whether the transmembranal cysteines in Sindbis virus also were palmitylated, we used site-directed mutation to change the single transmembranal cysteine in the E1 glycoprotein and two of the transmembranal cysteines in the E2 glycoprotein to alanines. Transfection of RNA transcribed from the differently mutated Sindbis virus cDNAs led to production of infectious virus. Cells infected with the mutant virions and labeled with [3H]-palmitic acid showed that the E1 mutant no longer contained fatty acid in the E1 glycoprotein and that the extent of palmitylation was reduced about twofold in the E2 glycoprotein of virions containing the E2 mutations. At early times postinfection, the mutants grew slightly slower than the wild type in cultures of chicken embryo fibroblasts and secreted about half the amount of virus particles as wild type, but little difference was found at later time points. A triple mutant containing both the E1 and E2 mutations formed virions deficient in palmitylation of both glycoproteins, and this mutant had growth properties that were similar to those of the independent E1 and E2 mutants. Virions with the mutated glycoproteins that were deficient in fatty acid were more susceptible than the wild-type virions to inactivation by the detergent Triton X-100.

[The lead level in the blood of pregnant women from the city of Sofia]

The study was aimed at establishing the relation between blood lead, nutrient intake and smoking habits of pregnant and nonpregnant women in Sofia. Forty four pregnant in the last trimester of pregnancy and 14 nonpregnant women were examined. There are no differences between the mean blood lead level of the groups. 22.72% of the pregnant and 37.7% of the nonpregnant women studied had blood lead above the accepted tolerable value of 0.48 mumol/l. It was established low intake of calcium, zinc and iron, minerals that contribute to lead bioavailability. A positive correlation between the number of cigarettes smoked and blood lead concentration was established. Based on this study it can be concluded that non-professional external exposure of lead in Sofia is significant. Smoking is eventually one contributing factor that can be excluded to reduce lead exposure.

Mutations in the Sindbis virus capsid gene can partially suppress mutations in the cytoplasmic domain of the virus E2 glycoprotein spike

Assembly and budding of alphaviruses are postulated to occur by protein-protein interactions between sites on the cytoplasmic domain of the transmembranal envelope E2 glycoprotein and on the surface of the nucleocapsid protein subunits. Genetic data to support this model have been obtained by isolating revertants of two slow-growth mutants of Sindbis virus and analyzing the sequences of the genes encoding their structural proteins. The slow-growth phenotypes of the mutants were previously shown to result from site-directed mutations of 2 amino acids in the sequence corresponding to the 33 amino acids at the carboxyl terminus of E2, which are localized to the cytoplasmic face of the plasma membrane. Putative revertants of these two mutants with faster growth rates were isolated by sequential passaging of virus grown on insect cells or chicken embryo fibroblasts. Sequence analysis of plaque-purified viruses that grew significantly better than the original mutant revealed that the original E2 mutation was present and that there were additional amino acid changes in the virus capsid. Two of the latter were introduced separately into the wild-type virus cDNA and into the genomes of the original mutants. The new strains of virus that contained both capsid and E2 mutations produced many more extracellular particles than those with the E2 mutations alone, indicating substantial suppression of the original E2 mutation. Both capsid mutations appear to be localized near a hydrophobic pocket of the capsid, which is postulated to be the site for docking of hydrophobic amino acids of the E2 cytoplasmic domain. This genetic study provides strong support for the current models of alphavirus assembly.

Characterization of revertants of a Sindbis virus 6K gene mutant that affects proteolytic processing and virus assembly

Alphaviruses of the Togaviridae encode a small hydrophobic polypeptide of 55 amino acids, noted as the 6K protein, that is synthesized as part of a polyprotein containing the sequences of the two major transmembranal viral structural glycoproteins. Mutations, insertions and deletions in the 6K appear to selectively interfere with the final stages of virus assembly and budding, producing aberrant, multi-cored infectious viruses. In addition, some of these mutations were pleiotropic and much more inhibitory to virus formation. One of the latter, a substitution of alanine in the wild-type Sindbis virus 6K gene by arginine, has been studied further and shown to interfere with normal proteolytic processing of the polyprotein. Cells infected with this mutant but not the wild-type virus also displayed viral antigens in nuclear membranes and released fragments of membranes into the cell culture media. A revertant, obtained by enrichment for a faster growing strain, 'suppressed' these defects and genetic mapping showed that the arginine codon had been modified to encode a methionine. However, the sequence of the 6K protein in this revertant was not wild-type and the revertant was still defective in assembly as demonstrated by formation of aberrant particles. A complete restoration of wild-type particle formation for this revertant could be effected by modifying the E2 glycoprotein sequence.

A pseudo-revertant of a Sindbis virus 6K protein mutant, which corrects for aberrant particle formation, contains two new mutations that map to the ectodomain of the E2 glycoprotein

Most site-directed mutations in the gene encoding the small, membrane-associated 6K protein of Sindbis virus interfere selectively with virus assembly and budding. Particles are released that are aberrant in structure, with a single membrane enclosing multiple nucleocapsids. A revertant for the mutation that inserted a serine for a cysteine at position 39 in the 6K protein was isolated and found to correct for the defective budding so that normal particles were formed. Genetic analysis of this revertant showed that two additional mutations, which were mapped to the ectodomain of the E2 virus glycoprotein, were present in addition to the original 6K substitution. The phenotype of the revertant differed from the wild-type strain and the original mutation with regard to plaque size, thermostability, and growth in neuronal cells. Five new virus genetic constructs were prepared by insertion of these mutations into the wild-type virus. Phenotypes of these constructs confirmed that the mutations in the E2 ectodomain were responsible for both correcting the original defect in budding as well as imparting changes in cell tropism, plaque size, and thermolability on the virus. These results indicate that 6K may play an indirect role in the packing of the virus spike glycoproteins, which allows for membrane deformation and bending during the budding process.

Diurnal rhythms of the neuroendocrine system in professional riveters with different constitutional types

In our earlier investigations it have been shown that experimental vibration exposure causes different endocrine reactions in hypothalamo-pituitary-adrenocortical (HPA) and hypothalamo-pituitary-gonadal (HPG) systems in men of different constitutional types. The present study was carried out to determine diurnal rhythms of HPA and HPG systems in professional male riveters during a working day under industrial conditions. The state of HPA and HPG systems was evaluated according to the concentration of hormones cortisol (Cort.) and testosterone (T) in saliva. Mixed saliva was collected without stimulation at 7.00, 11.00, 15.00, 19.00 and 23.00 h. The concentration of hormones was determined by radio-immunoassay. Only healthy workers with a long working time under vibration exposure were chosen for participation in the investigation. The workers were divided into three groups of abdominal (A), muscular (M) and pectoral (P) somatotypes according to the antropometric signs (Bunaris classification, 1941). The results of investigating the HPA system have shown that usual diurnal rhythm of Cort, was observed in 60% of all cases. This rhythm is characterised by the maximum concentration of Cort, at 7.00 h with subsequent lowering during the day. In 10% of all cases we observed very low concentration of Cort, at 7.00 h and in 30% there was a significant increase of the level of Cort, at 15.00 and 19.00 h. Another change of diurnal rhythm was revealed in the HPG system. The diurnal rhythm of T completely corresponds to the rhythm of Cort. The accordance of T concentration to the diurnal rhythm we observed only in 27% of all cases. In 47% of all cases the increase of T took place at 15.00 and 19.00 h and in 20% the "monotonous" curve of T concentration without any changes of rhythm and with a low concentration at 7.00 h was observed. We also revealed different distribution of A, M and P somatotypes in connection with various diurnal rhythms of hormone curves. The result allows us to suppose that constitutional dependence of changes of diurnal rhythm of HPA and HPG systems probably underlines the adaptive processes to long time vibration exposure.

Clinical significance of neutrophil functional activity in HIV infection

Functional activity of polymorphonuclear neutrophils (PMN) was tested in 63 HIV-1 infected patients. PMN chemiluminescence (CL) and intracellular enzyme activity were both depressed in patients at all stages of infection, though this depression was more pronounced in AIDS patients. We found no such depression when cells were incubated in the presence of autologous serum. PMN phagocytosis in the presence of serum was reduced in the early stage of HIV infection (LAS) but was in the normal range in AIDS patients. No differences in PMN functional activity between patients with LAS and those with dermatological disorders were found. The appearance of recurrent upper respiratory tract infection was associated with reduced PMN CL. The most pronounced changes in PMN activity were observed in patients with severe, recurrent bacterial pneumonia and Pneumocystis carinii pneumonia. A lower level of PMN activity was found in patients with infection progressing rapidly towards AIDS than in patients with a relatively stable course of infection. Thus, PMN CL may be regarded as a predictive factor for the progression of HIV infection.

Site-directed mutations in the Sindbis virus E2 glycoprotein identify palmitoylation sites and affect virus budding

The assembly and budding of Sindbis virus, a prototypic member of the alphavirus subgroup in the family Togaviridae, requires a specific interaction between the nucleocapsid core and the membrane-embedded glycoproteins E1 and E2. These glycoproteins are modified posttranslationally by the addition of palmitic acid, and inhibitors of acylation interfere with this budding process (M.J. Schlesinger and C. Malfer, J. Biol. Chem. 257:9887-9890, 1982). This report describes the use of site-directed mutagenesis to identify two of the acylation sites in the E2 glycoprotein as the cysteines near the carboxyl terminus of the protein which is oriented to the cytoplasmic domain of this type 1 transmembrane protein. Additional mutations were made at two prolines within a hydrophobic sequence of E2 that is highly conserved among several alphaviruses, and the mutant viruses were aberrant in assembly and particle formation. These data support earlier studies indicating that the native structure of the cytoplasmic domain of E2 is essential for proper assembly of this enveloped virus.

Cloning and sequencing of the S RNA from a Bulgarian isolate of tomato spotted wilt virus

Libraries of cloned cDNA were prepared from complete genomic RNA and isolated S RNA of the Bulgarian L3 isolate of tomato spotted wilt virus (TSWV-L3). Northern blotting of TSWV genomic RNA detected clones specific for the L, M and S RNAs in the library from complete RNA. S RNA-specific clones selected from both libraries covered approximately 2.8 kb (about 95%) of the S RNA. Sequencing of these clones showed TSWV-L3 S RNA to be ambisense. It contains two open reading frames (ORFs); one of 1401 nucleotides located on the viral RNA encodes an Mr 52,400 (52K) protein, and the other of 774 nucleotides on the complementary strand encodes an Mr 28,900 (29K) protein. Expression of the 29K ORF in bacteria and immunological analysis of the fusion protein synthesized confirmed that the 29K protein is the N protein of TSWV-L3. Comparison with the published sequence for the S RNA of a Brazilian TSWV isolate, CNPH1, revealed almost complete identity in the amino acid sequences for the 29K protein, but several clustered amino acid exchanges in the putative 52K protein. In addition, the separating non-translated intergenic region of the S RNA of the Bulgarian isolate is 81 nucleotides longer than that of CNPH1.