bluuebunny/crossref_metadata_2025 huggingface dataset:
Cytokine production in NOD mice on prophylactic insulin therapy
Authors: STRANDELL EVA , KAAS ANNE , HARTOFT‐NIELSEN MARIE‐LOUISE , BOCK TROELS , BUSCHARD KARSTEN , BENDTZEN KLAUS
Published: August 2009

We investigated whether cytokines produced primarily by monocytes/macrophages (IL‐1α), Th1‐lymphocytes (IFNγ), or Th2‐lymphocytes (IL‐4) are modulated in diabetes‐prone NOD mice by insulin treatment as used in prophylaxis studies. The cytokines were measured by ELISA in plasma and in supernatants of spleen cells activatedex vivoby lipopolysaccharide plus phytohemagglutinin. Insulin, 0.25–0.50 IU/day, was given subcutaneously for 8 weeks starting in 4‐week‐old female mice. The insulin‐treated and control NOD mice showed similar weight gains and, by the end of the study, both groups exhibited cell infiltration in about 25% of their islets. IL‐la, IFNγ and IL‐4 were generally below detection in plasma of prediabetic animals and controls. Diabetic NOD mice, aged 28–45 weeks, had significantly elevated plasma IL‐la: 154±39 pg/ml (mean±M, p<0.0001). While ex vivo activated NOD splenocytes released similar amounts of IL‐1α, insulin therapy increased the levels from 99±17 to 155±19 pg/106cells (p<0.05). Supernatants of activated splenocytes from prediabetic NOD mice had lower levels of IL‐4 (<15 pg/106cells) compared with those from BALB/c mice (88±22 pg/106cells; p<0.01), and this deficiency was partially compensated for when the NOD mice were given insulin (27±8; p<0.01). The levels of IFNγ were comparable and largely unaffected by insulin treatment. Hence, insulin therapy appears to partially normalize an otherwise deficient Th2 response in NOD mice.
Immunohistochemical expression of metallothionein in resected hepatic primary tumors and colorectal carcinoma metastases
Authors: STENRAM UNNE , OHLSSON BJÖRN , TRANBERG KARL‐GÖRAN
Published: August 2009

Metallothionein is a protein with affinity for metals and is present in several tumors. We examined its immunohistochemical expression in 37 resected primary liver tumors and 117 colorectal metastases. The reaction was intense in the two fibrolamellar hepatocellular carcinomas and in many of the hepatocytes of the pseudotumor case of focal nodular hyperplasia. The reaction was low or moderate in 5 of 17 ordinary hepatocellular carcinomas and in 4 of 14 cholangiocellular carcinomas. There was no reaction in one case each of spindle cell hepatocellular carcinoma, oncocytic adenoma and hemangioendothelial sarcoma. In the metastases, the reaction was low or moderate in 14 cases and negative in 103. Surrounding hepatocytes and stromal cells were more or less positive in all cases.
Frequency of α‐ and β‐haemolysin in Staphylococcus aureus of bovine and human origin
Authors: AARESTRUP F. M. , LARSEN H. D. , ERIKSEN N. H. R. , ELSBERG C. S. , JENSEN N. E.
Published: August 2009

The phenotypic expression of haemolysins and the presence of genes encoding a and β‐haemolysin were determined in 105 Staphylococcus aureus isolates from bovine mastitis, 100 isolates from the nostrils of healthy humans, and 60 isolates from septicaemia in humans. Furthermore, the possible change in expression of haemolysins after subcultivation in human and bovine blood and milk was studied in selected isolates. α‐haemolysin was expressed phenotypically in 39 (37%) of the bovine isolates, in 59 (59%) of the human carrier isolates, and in 40 (67%) of the isolates from septicaemia. β‐haemolysin was expressed in 76 (72%) bovine, 11 (11%) carrier, and 8 (13%) septicaemia isolates. Significantly more bovine than human isolates expressed β‐haemolysin and significantly fewer expressed α‐haemolysin. Genotypically, the gene encoding a‐haemolysin was detected in all isolates. A significant difference in the prevalence of the gene encoding β‐haemolysin between the bovine (96%), human carrier (56%) and isolates from septicaemia (57%) was found. Of the bovine isolates, 75% of those carrying the gene encoding β‐haemolysin expressed β‐haemolysin phenotypically, whereas only 20% of the carrier isolates and 24% of the septicaemia isolates did so. No change in expression of haemolysins could be observed after subcultivation of bovine isolates in human blood and milk. After 5 to 10 subcultures in bovine blood and 1 to 4 in bovine milk, 9 of 10 human isolates originally phenotypically β‐haemolysin negative initiated the expression of β‐haemolysin. This study showed that a larger proportion of S. aureus of bovine origin carry the β‐haemolysin gene compared to isolates from humans. Furthermore, a larger number of the isolates of bovine origin carrying the β‐haemolysin gene express this gene phenotypically compared to isolates of human origin.
Fas and Fas‐ligand expression in seminomatous testes
Authors: BRÆNDSTRUP O. , BOLS B. , JENSEN L.
Published: August 2009

Sixteen seminomas with surrounding tissue containing normal and precancerous (cis) seminiferous tubules were examined for the expression of Fas (CD95, APO‐1) and Fas ligand (FasL) (CD95L). This was done by analyzing frozen specimens using immunohistochemistry with antibodies directed against Fas and FasL. The study showed that varying numbers (mean approx. 20%) of Fas‐positive lymphocytes were present among tumor‐infiltrating lymphocytes, but very few FasL‐positive lymphocytes. Fas was not expressed by normal seminiferous tubules and only occasional Fas‐positive epithelial cells were seen in cis tubules. FasL was expressed in 9 out of 10 cases in virtually all normal seminiferous tubules, mainly as a thin layer at the base of the seminiferous epithelium. In precancerous tubules, this layer was discontinuous and less pronounced. Rete testis expressed FasL in 2 out of 2 cases with rete present and Fas in 1 out of 1 case. Invasive tumor cells did not express Fas or FasL. The data are discussed in relation to immune reactions to seminomas and to the concept of the testis being an immunologically privileged area.
Survival of human parathyroid tissue xenotransplanted in nude mice after 9 to 55 months' cryopreservation
Authors: SMEDS S. , TRULSSON L. , GAROVOY M. , GUMBERT M. , CLARK O. H.
Published: August 2009

Survival of human parathyroid tissue xenotransplanted after cryopreservation was studied. Peroperative biopsies from 26 patients were cryopreserved and xenoptransplanted into nude mice after 9 to 55 months. At 8 to 12 weeks after transplantation, the morphology of the transplanted tissue was compared to that of the original tissue after thawing and before transplantation. Morphologically viable tissue was observed in 20 out of 26 nude mice (77%). Based on the morphological appearance, the parathyroid transplants were arranged into four “quality” groups. No correlation existed between the quality of the transplants and duration of storage, or between the age and sex of the patients. There was no correlation between initial clinical diagnosis or histopathological patterns (1°, 2° and 3° hyperplasia [n=16], adenoma [n=9], one case undetermined) and transplant survival. After thawing and transplantation, all parathyroid grafts, except one, were morphologically either of the same or somewhat lower quality.
Detection of Chlamydia pneumoniae by colorimetric in situ hybridization
Authors: ALAKÄRPPÄ HANNU , SURCEL HELJÄ‐MARJA , LAITINEN KIRSI , JUVONEN TATU , SAIKKU PEKKA , LAURILA AINO
Published: August 2009

Chlamydia pneumoniae causes chronic infections, which have been associated with cardiovascular diseases. The antigenic structures of the organism have been detected in atherosclerotic lesions by immunohistochemistry.

We wanted to further evaluate the presence and localization of C. pneumoniae in different tissues by in situ hybridization. We established a new colorimetric in situ hybridization method using a digoxigenin‐labelled probe and studied the localization of C. pneumoniae in formalin‐fixed, paraffin‐embedded lungs of infected mice. We also used the method to study its presence in 12 abdominal aortic aneurysms. In C. pneumoniae‐infected mice, the organism was first detected in bronchial epithelial cells, and later in pneumocytes and endothelial cells. C. pneumoniae was also present in five of eight abdominal aortic aneurysms previously shown to be positive by immunohistochemistry. The findings are in accordance with the invasive nature of C. pneumoniae, and confirm its presence in abdominal aortic aneurysms.
Infection, inflammation and sleep: more pieces to the puzzle of sudden infant death syndrome (SIPS)
Authors: BLACKWELL C. C. , WEIR D. M. , BUSUTTIL A.
Published: August 2009

Risk factors for sudden infant death syndrome (SIDS) parallel those for respiratory tract infections; however, infectious agents suggested to be involved in SIDS do not fulfil Koch's postulates. No single agent has been identified in all cases and there is no suitable animal model for SIDS which could be used to test the candidate organisms. Based on epidemiological and experimental work by our group and others, we suggested some SIDS deaths are due to pathophysiological responses elicited by combinations of microbial products and/or cigarette smoke during a developmental stage when infants' endocrine responses are less able to “damp down” the effects of inflammatory mediators. Here we review evidence from studies on interactions between developmental and environmental risk factors that could affect 1) mucosal colonization of infants by potentially pathogenic bacteria, and 2) induction and control of infants‘, inflammatory responses to infectious agents. New evidence suggests that there are genetic factors involved in the induction of inflammatory responses to some bacterial antigens implicated in SIDS. Further investigation of the role of infection, exposure to cigarette smoke and inflammation in infants, particularly differences in ethnic groups at increased risk of SIDS, could lead to new insights into the events leading to a fatal outcome and perhaps to new intervention schemes to reduce further the incidence of these deaths.
Transient Tat activation of the HIVLAV/Lai‐1 LTR by primary HIV‐1 phenotypic variants in HeLaT4LTRβ‐gal cells
Authors: NILSEN MONA V. , ÅSJÖ BIRGITTA , SOMMERFELT MAJA A.
Published: August 2009

The rapid/high and slow/low phenotypic variants of primary HIV‐1 isolates can be distinguished by their differential co‐receptor utilization and their ability to productively infect established cell lines. To reveal possible differences in Tat‐mediated transactivation, the potential for primary isolate Tat proteins to transactivate the LTR from the laboratory strain HIVLAV/Lai‐1 was examined. Using either cell‐mediated or PEG‐induced fusion of cells infected with primary HIV‐1 isolates and HeLaT4LTRβ‐gal cells, it was clear that the Tat protein encoded by all patient isolates efficiently activated transcription from the HIVLAV/Lai‐1 LTR. However, infection of HeLaT4LTRβ‐gal cells by primary HIV‐1 isolates was transient, suggesting the development of a postpenetration host control of HIV‐1 replication at the level of tat activation, a feature not observed for the laboratory‐adapted strain HIVIIIB. Although plasmid vectors based on the HIVLAV/Lai‐1 LTR remain useful for the development of susceptible established cell lines for titrating primary HIV‐1 isolates, the efficacy of such a system would depend upon the stability/duration of Tat activation.
Apoptosis in acute pulmonary allograft rejection and cytomegalovirus infection
Authors: HANSEN PETER RIIS , HOLM ANNE METTE , SVENDSEN ULRIK GERNER , OLSEN PETER SKOV , ANDERSEN CLAUS BØGELUND
Published: August 2009

Apoptosis is a form of programmed cell death, characterized by activation of endonucleases that cleave DNA into oligonucleosomal fragments, which can be identified by in situ terminal deoxyribon‐ucleotide transferase‐mediated dUTP nick‐end labeling (TUNEL). This process has recently been implicated in cardiac and hepatic allograft rejection, and we investigated its contribution to acute pulmonary allograft rejection and cytomegalovirus (CMV) pneumonitis by in situ TUNEL of transbronchial biopsy specimens. In situ TUNEL was performed on 70 transbronchial biopsy samples collected from 25 pulmonary allograft recipients for diagnosis of acute rejection or CMV pneumonitis, and the number of apoptotic nuclei/mm2 was correlated with the rejection grade (International Society of Heart and Lung Transplantation classification). During acute pulmonary allograft rejection, apoptotic nuclei were demonstrated in pulmonary parenchymal cells and mononuclear infiltrating cells, and the number of apoptotic cells was positively correlated with the rejection grade. In addition, a marked increase in the density of apoptotic cells was found in pulmonary allografts with CMV pneumonitis. We conclude that apoptosis contributes to cell death during acute pulmonary allograft rejection and CMV infection.
A case of endometrioid carcinoma of the fallopian tube mimicking an adnexal tumor of probable Wolffian origin
Authors: KARPUZ VILDAN , BERGER SOPHIE DIEBOLD , BURKHARDT KARIM , MÉGEVAND ERIC , REMADI SAMI , KAPANCI YUSUF
Published: August 2009

We report a very uncommon case of endometrioid adenocarcinoma of the fallopian tube that mimicked, based on histology, a female adnexal tumor of probable Wolffian origin (FATPWO). We present our microscopic and immunohistochemical findings, and a review of the literature concerning these two entities. The differential diagnosis can be of great consequence, owing to the very different prognoses of the two tumors, and is based mainly on macroscopic appearance and immunohistochemical profile: epithelial membrane antigen (EMA) and CA125, generally lacking in FATPWO, are expressed in endometrioid adenocarcinoma, thus indicating the müllerian origin of this tumor.
Reactions of N‐N and N‐O compounds with horseradish peroxidase and peroxidases from Mycobacterium tuberculosis
Authors: BRIMNES JENS , MIÖRNER HÅKAN , ANTHONI UFFE , BRUUN LEIF , HOUEN GUNNAR
Published: August 2009

Several N‐N‐and N‐O‐containing compounds were analysed for their ability to act as substrates for horseradish peroxidase and peroxidases in Mycobacterium tuberculosis extracts. Aminoguanidine, diaminoguanidine, isoniazid, hydroxylamine and hydrazine were found to be weak substrates for horseradish peroxidase in reaction I and to inhibit the reaction of horseradish peroxidase with hydrogen peroxide. The same compounds inhibited the reaction of Mycobacterium tuberculosis peroxidase‐catalase with hydrogen peroxide, and hydroxylamine was found to be a weak substrate for this enzyme. In growth inhibition experiments, diaminoguanidine inhibited the growth of M. tuberculosis H37Rv at 50 μg/mL, but not the growth of two isoniazid‐resistant strains. Isonicotinic acid hydroxamate inhibited the reaction of the peroxidases with hydrogen peroxide, but was not itself a substrate and had no growth‐inhibitory effects. On the basis of these results we suggest that the effect of isoniazid on growth of M. tuberculosis results from increased oxidative stress due to inhibition of catalase‐peroxidase as well as from generation of toxic radicals with the structure .
Molecular detection of EWS‐FLI1 chimeric transcripts in Ewing family tumors by nested reverse transcription‐polymerase chain reaction: application to archival paraffin‐embedded tumor tissues
Authors: HISAOKA MASANORI , TSUJI SEIJI , MORIMITSU YOSUKE , HASHIMOTO HIROSHI , SHIMAJIRI SHOHEI , KOMIYA SETSURO , USHIJIMA MASAHIRO
Published: August 2009

Chromosomal translocations generating unique chimeric genes are highly characteristic of specific sarcomas, and their use as diagnostic markers has been suggested. From a diagnostic pathologic point of view, detection of such cytogenetic or molecular aberrations applicable to routinely processed archival tissue specimens is considered a powerful tool for tumor diagnosis. To assess the feasibility and reliability of the molecular detection of the transcript originating from the chimeric gene in paraffin‐embedded tumor specimens, we performed a nested reverse transcription‐polymerase chain reaction (RT‐PCR)‐based assay to detect the EWS‐FLI1 chimeric message in a series of Ewing family tumors. Of 24 paraffin‐embedded tumor specimens from 23 cases analyzed, the chimeric message was detectable in 20 (83%) specimens from 20 cases (87%) by this nested RT‐PCR assay, whereas none of 7 small round cell tumors not from this family (3 alveolar rhabdomyosarcomas, 2 neuroblastomas, 2 malignant lymphomas) showed detectable chimeric messages. In the sequence analysis of the PCR products, the amplified chimeric messages contained the junctions between exon 7 of the EWS gene and any one of exons 5, 6 and 8 of the FLI1 gene. The detection process was usually completed within 3 days, except for the subseqent sequence analysis. Our results endorse the use of this molecular assay as an ancillary technique in the diagnosis of Ewing family tumors using paraffin‐embedded material.
Development of resistance and cross‐resistance in Pseudomonas aeruginosa exposed to subinhibitory antibiotic concentrations
Authors: WU Y. L. , SCOTT E. M. , PO A. LI WAN , TARIQ V N.
Published: August 2009

The purpose of this study was to compare resistance and cross‐resistance development in Pseudomonas aeruginosa isolates from cystic fibrosis (CF) patients to commonly used antipseudomonal antibiotics. Isolates were repeatedly exposed to subinhibitory concentrations of either azlocillin, tobramycin, ceftazidime or ciprofloxacin. On 10 consecutive occasions, samples were removed from the half‐MIC well of a microtitre plate and regrown in drug‐free medium to provide the next inoculum for MIC determination. The increase in MIC at the end of the treatment period was significant (p<0.05) for all selecting antibiotics. Cross‐resistance to unrelated antibiotics was not observed, but was significant (p<0.05) in all β‐lactams (ticarcillin, piperacillin, ceftazidime and cefsulodin) studied where azlocillin was the selecting antibiotic. The addition of clavulanic acid to ticarcillin and of tazobactam to piperacillin had no effect on cross‐resistance. The development of resistance to azlocillin was associated with increased β‐lactamase activity and a change in isoelectric point of the β‐lactamases. The result of this study supports a rotational policy for antipseudomonal antibiotics in CF patients.
C‐reactive protein (CRP) response patterns in neonatal septicaemia
Authors: RØNNESTAD A. , ABRAHAMSEN T. G. , GAUSTAD P. , FINNE P. H.
Published: August 2009

C‐reactive protein (CRP) is an unreliable diagnostic tool in the early diagnosis of neonatal septicaemia. However, serial measurements have been shown to be useful in monitoring the effectiveness of treatment. The aim of the present study was to investigate whether a specific CRP response pattern to different groups of pathogens could be identified during treatment of neonatal septicaemia. Serial CRP measurements from day 1 to 4 in monomicrobial blood culture‐proven episodes of septicaemia were reviewed. In 4416 admissions, 180 out of 206 positive blood cultures were monomicrobial; 121 monomicrobial septic episodes were eligible for final analysis of the CRP response during treatment. A low median (M) value (day 1 to 4) was identified in coagulase‐negative staphylococci (CONS) (M=23 mg/l), contrasting with high median values in Staphylococcus aureus (M=58 mg/l), group B streptococci (M=51 mg/l), Escherichia coli (M=51 mg/l) and Candida species (M=76 mg/l) (p<0.001). Median CRP values in the two groups were different for each of the treatment days 1 to 4 (p<0.001). An increase (p<0.001) in CRP during the 24 h before initiation of treatment was a sign of late‐onset CONS septicaemia. In episodes where antimicrobial treatment failed, CRP levels were moderately elevated the day prior to treatment start and increased continuously thereafter, whereas successful treatment was generally accompanied by a decline in CRP in less than 4 days. The CRP response to CONS is significantly less pronounced than to other commonly encountered pathogens in neonatal septicaemia. A rise in CRP beyond the third day of empirical treatment should give rise to a suspicion of fungal infection or ineffective antibacterial treatment.
Detection of pneumococcus from whole blood, buffy coat and serum samples by PCR during bacteremia in mice
Authors: SALO PAULA , LAITINEN KIRSI , LEINONEN MAIJA
Published: August 2009

Whole blood, purified leukocyte fraction and serum were investigated as specimens for the detection of pneumococcal bacteremia by polymerase chain reaction (PCR) in mice. The PCR findings were compared to the blood culture results. Samples were taken from animals 3 and 12 h after intraperitoneal bacterial challenge. The pneumococcal culture was positive in 27% and 77% of blood samples at 3 and 12 h after challenge, respectively. All whole blood samples were positive by PCR at both time points. Of the buffy coat samples, two of the three pools were PCR‐positive at 3 h and all pools at 12 h after bacterial challenge. In the serum sample group, only 40% of the sera were PCR‐positive at 3 h, while at 12 h 90% of the samples were PCR‐positive. According to these results, whole blood seems to be the best specimen for the detection of pneumococcal DNA by PCR in bacteremic mice.
Loss of bactericidal capacity of long‐chain quaternary ammonium compounds with protein at lowered temperature
Authors: AHLSTRÖM B. , THOMPSON R. A. , EDEBO L.
Published: August 2009

Amphiphilic betaine esters are quaternary ammonium compounds (QACs) with rapid microbicidal effect, which spontaneously hydrolyze into nontoxic products, thus being referred to as soft antimicrobial agents. The bactericidal effect of 1‐decyl (B10), 1‐dodecyl (B12), and 1‐tetradecyl (B14) betaine esters on Salmonella typhimurium was strongly influenced by temperature, pH and length of hydrocarbon chain. At pH 6.0, presence of 1.5 mM (10% w/v) BSA raised the concentration of B14 for 99% killing (BC2) from 0.006 mM to 1.8 mM. There was a stoichiometric relationship between concentration of BSA and BC2 of B14, indicating that one molecule of B14 was bound per BSA molecule when 99% killing was achieved. When the temperature was lowered to 0°C only minor killing was seen in 1.5 mM BSA at the highest concentration of B14 tested, 57 mM. With B10 at 30°C and pH 6.0, the presence of 1.5 mM BSA raised the bactericidal concentration (BC2) from 0.69 mM to 4.1 mM, and at 0°C and 1.5 mM BSA the BC2 was 11 mM. Thus, the impairment caused of the bactericidal effect of B10 by BSA and lower temperature was less than for B14, since B14 is much more active than B10 at 30°C in the absence of BSA, somewhat more active than B10 at 30°C in the presence of 1.5 mM BSA, and much less active than B10 at 0°C in the presence of BSA. B12 showed properties intermediate between B10 and B14. Lowered pH reduced the bactericidal effect particularly when reduced from pH 5.0 to 4.0 with B10. In the presence of 1.5 mM BSA, the bactericidal effect of 1‐dodecyl (DTAB) and 1‐hexadecyl (CTAB) trimethylammonium bromide decreased in the same manner as for B10 and B14, respectively. Increasing the time of incubation at 0°C to 50 min, a 99% killing effect was seen with 17 mM CTAB, whereas the same killing effect was reached in 8 min with 17 mM DTAB. Binding of [3H]CTAB to S. typhimurium was also reduced at 0°C in the presence of BSA. Thus, in the presence of 1.5 mM BSA, QACs with the longer hydrocarbon chain were most efficient at 30°C, whereas at 0°C those with the shorter hydrocarbon chain were most active. Consequently, QACs with shorter tails should be used for disinfection in the presence of proteins at lower temperatures.
Experimental Study of the Aging and Self‐Healing of the Glass/Ceramic Sealant Used in SOFCs
Authors: Liu Wenning N. , Sun Xin , Koeppel Brian , Khaleel Mohammad
Published: August 2009

High operating temperatures of solid oxide fuel cells (SOFCs) require that the sealant must function at a high temperature between 600°C and 900°C and in the oxidizing and reducing environments of fuel and air. This paper describes tests to investigate the temporal evolution of the volume fraction of ceramic phases, the evolution of micro‐damage, and the self‐healing behavior of the glass–ceramic sealant used in SOFCs. It was found that after the initial sintering process, further crystallization of the glass–ceramic sealant does not stop, but slows down and reduces the residual glass content while boosting the ceramic crystalline content. Under a long‐term operating environment, distinct fibrous and needle‐like crystals in the amorphous phase disappeared, and smeared/diffused phase boundaries between the glass phase and ceramic phase were observed. Meanwhile, the micro‐damage was induced by the cooling down process from the operating temperature to room temperature, which can potentially degrade the mechanical properties of the glass/ceramic sealant. The glass/ceramic sealant exhibited self‐healing upon reheating to the SOFC operating temperature, which can restore the mechanical performance of the glass/ceramic sealant.
Effect of Electrical Current on Solid Oxide Fuel Cells Metallic Interconnect Oxidation in Syngas
Authors: Li Yihong , Jiang Yinglu , Wu Junwei , Pineault Richard , Gemmenn Randall , Liu Xingbo
Published: August 2009

Electrical current flow is one of the important factors influencing high‐temperature oxidation of SOFC interconnects. To understand the effect of electric current on corrosion behavior, Crofer 22 APU and Haynes 230//SS430 clad coupons were exposed to a simulated coal syngas at 800°C with a current density of 0.5 A/cm2, for 500 h. It was found that the scale formed on the positive side was thicker than that formed on the negative side. In particular, for Crofer 22 APU, the morphology of the scale formed on the positive side was whisker‐like while the scale formed on the negative side was predominantly cubic‐shaped crystals. For Haynes 230//SS430 clad sample, some grain‐shaped crystals appeared on SS 430 (negative) side due to the breakaway oxidation.
Laser Melting of Spark Plasma‐Sintered Zirconium Carbide: Thermophysical Properties of a Generation IV Very High‐Temperature Reactor Material
Authors: Jackson Heather F. , Jayaseelan Daniel D. , Lee William E. , Reece Michael J. , Inam Fawad , Manara Dario , Casoni Carlo Perinetti , De Bruycker Franck , Boboridis Konstantinos
Published: August 2009

Melting temperatures of zirconium carbide were investigated in validating a novel thermal analysis technique for refractory materials. Commercial ZrC0.96 powder was densified by spark plasma sintering to >96% relative density after 6–30 min at 2173–2453 K under 40–100 MPa. Sintered ceramics were heated to >4000 K via pulsed laser heating. Mean values for solidus and liquidus transitions were 3451 and 3608 K, respectively, in fair agreement with the present phase diagram. Postmelting analysis revealed dendritic microstructure and composition consistent with single‐phase ZrC. Subsurface gas porosity and ZrC–C eutectic indicate complex processes occurring during melting and freezing.
Deviation from the cosmological constant or systematic errors?
Authors: Qi Shi , Lu Tan , Wang Fa-Yin
Published: August 2009

In the work of Qi, Wang & Lu, gamma-ray bursts (GRBs) are used together with an earlier Type Ia supernova (SN Ia) data set to constrain the dark energy equation of state (EOS) in a nearly model-independent way. The improvements made by including GRBs show a slight shift of the dark energy EOS toward w > −1 at redshifts z≳ 0.5. It is interesting that, when we have more SNe Ia, SNe Ia themselves also show the same trend. Motivated by the fact that both SNe Ia and GRBs seem to prefer a dark energy EOS greater than −1 at redshifts z≳ 0.5, we perform a careful investigation of this situation, including more careful treatments of measurement errors of GRBs and cross-checking the results by using different ways of including GRBs. We find that the deviation of dark energy from the cosmological constant at redshifts z≳ 0.5 is large enough that we should pay close attention to it with future observational data. Such a deviation may arise from some biasing systematic errors in the handling of SNe Ia and/or GRBs, or more interestingly from the nature of the dark energy itself.
Spin-down rate and inferred dipole magnetic field of the soft gamma-ray repeater SGR 1627–41
Authors: Esposito P. , Burgay M. , Possenti A. , Turolla R. , Zane S. , De Luca A. , Tiengo A. , Israel G. L. , Mattana F. , Mereghetti S. , Bailes M. , Romano P. , Götz D. , Rea N.
Published: August 2009

Using Chandra data taken in 2008 June, we detected pulsations at 2.594 39(4) s in the soft gamma-ray repeater SGR 1627−41. This is the second measurement of the source spin period and allows us to derive for the first time a long-term spin-down rate of (1.9 ± 0.4) × 10−11 s s−1. From this value, we infer for SGR 1627−41 a characteristic age of ∼2.2 kyr, a spin-down luminosity of ∼4 × 1034 erg s−1 (one of the highest among sources of the same class), and a surface dipole magnetic field strength of ∼2 × 1014 G. These properties confirm the magnetar nature of SGR 1627−41; however, they should be considered with caution since they were derived on the basis of a period derivative measurement made using two epochs only, and magnetar spin-down rates are generally highly variable. The pulse profile, double-peaked and with a pulsed fraction of 13 ± 2 per cent in the 2–10 keV range, closely resembles that observed by XMM–Newton in 2008 September. Having for the first time a timing model for this soft gamma-ray repeater (SGR), we also searched for a pulsed signal in archival radio data collected with the Parkes radio telescope 9 months after the previous X-ray outburst. No evidence for radio pulsations was found, down to a luminosity level ∼10–20 times fainter (for a 10 per cent duty cycle and a distance of 11 kpc) than the peak luminosity shown by the known radio magnetars.
Studies with Regard to the Apoptosis of Testicular Germ Cells in Rats Fed a Diet Enriched with Polyunsaturated Fatty Acids
Authors: Bertelsmann Holger , Behne Dietrich , Kyriakopoulos Antonios
Published: August 2009

The essential trace element selenium and polyunsaturated fatty acids (PUFA) have been used for the prevention of cancer. Both nutrients enhance the apoptosis of malignant cells and provide health benefits. However, an increased dietary intake of PUFA augments the susceptibility of lipid peroxidation and oxidative damage in many cells. So far, relatively few data are available about the interaction of selenium and PUFA in testis and thus a possible effect of both dietary components on the prevention of testicular cancer or on the apoptosis of testicular germ cells. Male germ cells in the rat contain most of the testicular phospholipid hydroperoxide glutathione peroxidase (PHGPx), mainly as the mitochondrial isoform of this selenoprotein (m‐PHGPx). An experiment was therefore carried out to determine the action of fish oil, a nutrient rich in PUFA, on the testicular expression of PHGPx. Because the PHGPx formation remains nearly unchanged in the animals fed the PUFA‐enriched diet, we conclude that no apoptosis of testicular germ cells is induced by an increased intake of this nutrient. The intake of fish oil in the selenium‐deficient animal led to a markedly altered formation of several selenium‐containing proteins, including sperm nuclei glutathione peroxidase (snGPx), also designated as the nuclear form of PHGPx (n‐PHGPx), and a 10‐kDa selenium‐containing protein.
Stanniocalcin, a Potential Ovarian Angiogenesis Regulator, Does Not Affect Endothelial Cell Apoptosis
Authors: Basini Giuseppina , Bussolati Simona , Santini Sujen Eleonora , Grasselli Francesca
Published: August 2009

The ovarian follicle represents an outstanding model for the investigation of the angiogenic process. In fact, follicular development is associated with an extensive neovascularization, and physiological angiogenesis is necessary for folliculogenesis. However, although the major factors triggering the angiogenic events have been thoroughly investigated and are now relatively well defined, information about the molecular events involved in the modulation and/or arrest of neovascularization is still scarce. Therefore, this research focused on the potential involvement of stanniocalcin (STC), a protein whose biological function is still unclear, in the control mechanisms of follicular angiogenesis. We evaluated the effect of 5 and 50 ng/mL STC on the production of the main proangiogenic factor, vascular endothelial growth factor (VEGF), by swine granulosa cells. Moreover, STC's effect on cell viability and the modulation of caspase‐3 and ‐7 activities in swine aortic endothelial cells were also examined. Granulosa cell VEGF production was significantly (P < 0.001) inhibited by STC. Endothelial cell viability was significantly (P < 0.001) increased, whereas caspase activities were reduced (P < 0.01) by STC. These data indicate that STC is not angiosuppressive for endothelial cells, although it could potentially modulate local angiogenesis acting at the granulosa cell level.
AIF: Not Just an Apoptosis‐Inducing Factor
Authors: Joza Nicholas , Pospisilik J. Andrew , Hangen Emilie , Hanada Toshikatsu , Modjtahedi Nazanine , Penninger Josef M. , Kroemer Guido
Published: August 2009

Since its discovery nearly a decade ago, apoptosis‐inducing factor (AIF) has had anything but a staid and uneventful existence. AIF was originally described as a mitochondrial intermembrane protein that, after apoptosis induction, can translocate to the nucleus and trigger chromatin condensation and DNA fragmentation. Over the years, an AIF‐mediated caspase‐independent cell death pathway has been defined. Rather than functioning as a general component of the cell death machinery, AIF is required for specific cell death pathways, including lethal responses to excitotoxins such as N‐methyl‐d‐aspartate and glutamate, the DNA‐alkylating agent N‐methyl‐N'‐nitro‐N‐nitroso‐guanidine, hypoxia–ischemia, or growth factor deprivation. Also, important roles of AIF in mitochondrial metabolism and redox control, and more recently in obesity and diabetes, have been discovered. Much of our knowledge has come from studies of AIF orthologs in model organisms, Saccharomyces cerevisiae, Caenorhabditis elegans, Drosophila melanogaster, and mice, which have also highlighted the importance of AIF in animal physiology and human pathology. Here, we discuss the manifold nature of AIF in cell life and death, with particular emphasis of its roles in vivo.
Acriflavine‐Mediated Apoptosis and Necrosis in Yeast Candida utilis
Authors: Keyhani Ezzatollah , Khavari‐Nejad Sarah , Keyhani Jacqueline , Attar Farnoosh
Published: August 2009

Acriflavine is an antiseptic, fungicide, and effective agent against parasitic infections, inducing petite mutation in the yeast Saccharomyces cerevisiae and kinetoplast loss in Trypanosomidae. Here we showed that acriflavine caused both apoptosis and necrosis in the yeast Candida utilis. Cells were cultured in minimal medium, with 1.5% ethanol as substrate, in the presence of 30–180 μmol/L acriflavine. Fluorescence measurements showed a linear concentration–dependence flux of the drug into the cells. Acriflavine induced a decrease in cell number, an increase in trypan blue–positive cells, and a decrease in cell viability. Cells cultured in the presence of acriflavine showed an alteration in their respiratory control ratio and a decrease in their cytochrome content. Fluorescence microscopy, after acridine orange staining, revealed the presence of apoptotic cells in cultures conducted in the presence of acriflavine. Electron microscopy of cells grown in the presence of acriflavine showed apoptotic cells exhibiting chromatin condensation, cytoplasmic lysis, but reasonably well‐preserved mitochondria, whereas necrotic cells showed no distinctive intracellular organelles. Data showed that acriflavine caused both apoptosis and necrosis. Moreover, acriflavine induced oxidative phosphorylation uncoupling. Generally, apoptosis is considered to be mediated either by a change in mitochondrial permeability and cytochrome c release or by plasma membrane death receptor activation. The outer mitochondrial membrane permeability to cytochrome c, with efflux of protons to the cytosol and cytoplasmic acidification, produced a collapse in the electrochemical proton gradient, a decrease in ATP synthesis, and subsequent cytolysis leading to apoptosis and necrosis.
Structural and Functional Alterations of Catalase Induced by Acriflavine, a Compound Causing Apoptosis and Necrosis
Authors: Attar Farnoosh , Khavari‐Nejad Sarah , Keyhani Jacqueline , Keyhani Ezzatollah
Published: August 2009

Acriflavine is an antiseptic agent causing both apoptosis and necrosis in yeast. In this work, its effect on the structure and function of catalase, a vital enzyme actively involved in protection against oxidative stress, was investigated. In vitro kinetic studies showed that acriflavine inhibited the enzymatic activity in a competitive manner. The residual activity detectable after preincubation of catalase (1.5 nmol/L) with various concentrations of acriflavine went from 50% to 20% of the control value as the acriflavine concentration increased from 30 to 90 μmol/L. Correlatively with the decrease in activity, alterations in the enzyme's conformation were observed as indicated by fluorescence spectroscopy, circular dichroism spectroscopy, and electronic absorption spectroscopy. The enzyme's intrinsic fluorescence obtained upon excitation at either 297 nm (tryptophan residues) or 280 nm (tyrosine and tryptophan residues) decreased as a function of acriflavine concentration. Circular dichroism studies showed alterations of the protein structure by acriflavine with up to 13% decrease in α helix, 16% increase in β‐sheet content, 17% increase in random coil, and 4% increase in β turns. Spectrophotometric studies showed a blueshift and modifications in the chromicity of catalase at 405 nm, corresponding to an absorbance band due to the enzyme's prosthetic group. Thus, acriflavine induced in vitro a profound change in the structure of catalase so that the enzyme could no longer function. Our results showed that acriflavine, a compound producing apoptosis and necrosis, can have a direct effect on vital functions in cells by disabling key enzymes.
Apoptosis Does Not Mediate Macrophage Depletion in Rabbit Atherosclerotic Plaques after Dietary Lipid Lowering
Authors: Martinet Wim , Croons Valerie , Herman Arnold G. , De Meyer Guido R.Y.
Published: August 2009

Unstable atherosclerotic plaques are characterized by a thin fibrous cap that contains few smooth muscle cells (SMCs) and numerous foam cells of macrophage origin. Previously we and others demonstrated that macrophages disappear from atherosclerotic plaques after dietary lipid lowering. However, it remains unclear whether loss of macrophages after lipid lowering occurs via increased apoptosis, decreased macrophage replication and/or recruitment, or via a combination of both. Rabbits were fed a diet supplemented with cholesterol (0.3%) for 24 weeks followed by a normal diet for 4, 12, or 24 weeks. After 24 weeks of cholesterol supplement, plaques showed apoptosis in both macrophages and SMCs, as determined by terminal deoxynucleotidyl transferase dUTP nick‐end labeling. Cell replication (Ki‐67 immunolabeling) was predominantly present in macrophages. After 24 weeks of cholesterol withdrawal, the thickness and areas of the plaques were unchanged. Nevertheless, plaques showed a considerable loss of macrophages. This event was associated with a reduced immunoreactivity for vascular cell adhesion molecule‐1 (VCAM‐1) in the endothelial cells starting 4 weeks after cholesterol withdrawal. Apoptosis did not increase after lipid lowering but showed a steady decline. Apart from decreased VCAM‐1 expression, a strong decrease in Ki‐67 immunolabeling was observed after 12 weeks of cholesterol withdrawal. Our findings suggest that loss of macrophages in atherosclerotic plaques after dietary lipid lowering is not related to induction of macrophage apoptosis but mainly a consequence of impaired monocyte recruitment followed by decreased macrophage replication. This information is essential for understanding the effects of aggressive lipid lowering on plaque stability.
Transforming Growth Factor‐β1 and Regulators of Apoptosis
Authors: Sulkowski Stanislaw , Wincewicz Andrzej , Sulkowska Mariola , Koda Mariusz
Published: August 2009

Growth inhibitory function of transforming growth factor‐β1 (TGF‐β1) is abolished in colorectal cancer cells as a consequence of mutations of various downstream signaling agents, such as p53, which fail to respond to TGF‐β1 stimulation. TGF‐β1 could also suppress T‐cell‐mediated anticancer immunity. We aimed at a comparison between cancer expressions of apoptosis regulators, such as p53, BCL‐2‐associated X protein (Bax), and B‐cell leukemia/lymphoma extra‐long protein (Bcl‐xL), with TGF‐β1 in malignant and adjacent inflammatory cells in immunohistochemical evaluations of 108 colorectal cancers. Cytoplasm compartment of cancer cells was overloaded with TGF‐β1, and 87% of all cancers were TGF‐β1 positive (94/108). A very strong pattern of staining was detected for TGF‐β1 in cytoplasm of inflammatory cells at tumor margins. TGF‐β1 correlated with Bcl‐xL and Bax in all colorectal cancers (P < 0.001, r= 0.473 and P < 0.001, r= 0.435, respectively) and subgroups of different clinicopathological features, especially in deeply invading cancers (pT3+pT4) instead of superficially growing tumors (pT1+pT2). Expression of TGF‐β1 in inflammatory infiltrates correlated with immunoreactivities to Bcl‐xL of cancer cells (P= 0.024, r= 0.217). TGF‐β1 did not associate with p53, nor did TGF‐β1 of inflammatory cells correlate with Bax expression in cancer cells. Lack of correlations between TGF‐β1 and p53 proteins could indicate mutations at the TGF‐β1‐dependent apoptotic pathway. Dominant positive linkage between TGF‐β1 and Bcl‐xL and selective lack of association with Bax suggest TGF‐β1 could support colorectal cancer cell survival. The pattern of correlations seems to confirm a remarkable shift from TGF‐β1‐dependent suppression of cancer growth by apoptosis to inhibition of anticancer immunity by TGF‐β1.
Protective Mechanism of Quercetin and Rutin Using Glutathione Metabolism on H2O2‐induced Oxidative Stress in HepG2 Cells
Authors: Kim Gyo‐Nam , Jang Hae‐Dong
Published: August 2009

The levels of cellular glutathione (GSH) and reactive oxygen species (ROS) simultaneously determined by fluorometric measurement, may provide important information on pro‐oxidative and antioxidative balance. The dual effect of quercetin antioxidant and pro‐oxidant activity was proposed from different studies. Our study demonstrated that quercetin acted as an antioxidant in HepG2 cells when cells were treated with 10 and 100 μmol/L quercetin for 30 min, but quercetin acted as a pro‐oxidant when cells were incubated at 100 μmol/L quercetin for longer periods (12 and 24 h). Quercetin is capable of reducing H2O2‐induced oxidative stress of HepG2 cells through different mechanisms, such as detoxification of H2O2, inhibition of ROS generation, and removal of generated ROS. We find that quercetin can block ROS generation through Fenton reaction to produce hydroxyl radicals by chelating with transition metal ions such as Cu2+. Evidence that quercetin might exert an antioxidant effect by changing generated ROS into less reactive ROS suggests that when quercetin reacts with ROS, it becomes oxidized, which is less harmful but still reactive, and the oxidized quercetin interacts with thiol compounds as reduced GSH to return to the parent compound quercetin. In contrast, the prolonged treatment of quercetin in high concentrations (100 μmol/L) shows that quercetin may act as a pro‐oxidant rather than as an antioxidant, resulting in cell death (apoptosis).
Ginkgolide B Induces Apoptosis via Activation of JNK and p21‐Activated Protein Kinase 2 in Mouse Embryonic Stem Cells
Authors: Hsuuw Yan‐Der , Kuo Tzong‐Fu , Lee Kun‐Hsiung , Liu Yen‐Chih , Huang Yu‐Ting , Lai Ching‐Yu , Chan Wen‐Hsiung
Published: August 2009

Ginkgolide B (GKB), the major active component of Ginkgo biloba extracts, can both stimulate and inhibit apoptotic signaling. We previously showed that ginkgolide treatment of mouse blastocysts induces apoptosis, decreases cell numbers, retards the proliferation and development of mouse embryonic stem cells and blastocysts in vitro, and causes developmental injury in vivo. However, the precise molecular mechanisms underlying its actions are currently unknown. Here, our study further revealed that GKB induced apoptotic biochemical changes, including activation of JNK, caspase‐3, and p21‐activated protein kinase 2 (PAK2), in ESC‐B5 mouse embryonic stem cells. Treatment of ESC‐B5 cells with a JNK‐specific inhibitor (SP600125) reduced GKB‐induced activation of both JNK and caspase‐3, indicating that JNK activity is required for GKB‐induced caspase activation. Experiments using caspase‐3 inhibitors and antisense oligonucleotides against PAK2 showed that caspase‐3 activation is required for PAK2 activation and both of these activations are required for GKB‐induced apoptosis in ESC‐B5 cells.
Phloretin Induces Apoptosis in H‐Ras MCF10A Human Breast Tumor Cells through the Activation of p53 via JNK and p38 Mitogen‐Activated Protein Kinase Signaling
Authors: Kim Mi‐Sung , Kwon Jung Yeon , Kang Nam Joo , Lee Ki Won , Lee Hyong Joo
Published: August 2009

Mutations in Ras play a critical role in the development of human cancers, including breast cancer. We investigated the possible antiproliferative effects of the naturally occurring dihydrochalcone phloretin [2′,4′,6′‐trihydroxy‐3‐(4‐hydroxyphenyl)‐propiophenone] on H‐Ras‐transformed MCF10A human breast epithelial (H‐Ras MCF10A) cells. Phloretin suppressed H‐Ras MCF10A cell proliferation in a dose‐dependent manner and induced nuclear condensation in the cells, indicating that phloretin‐induced cell death occurs mainly via the induction of apoptosis. Prominent upregulation of p53 and Bax and cleavage of poly (ADP)‐ribose polymerase were also detected in the phloretin‐treated cells. Finally, phloretin markedly increased caspase‐3 activity as well as JNK and p38 mitogen‐activated protein kinase signaling. Our findings suggest that the phloretin‐induced apoptosis of breast tumor cells contributes to the chemopreventive potential of phloretin against breast cancer.
In Vitro Biochemical and Pharmacological Evaluation of a Novel Cytotoxic Dinuclear Platinum(II) Complex with 3‐Amino‐5‐methyl‐5‐phenylhydantoin
Authors: Momekov Georgi Ts. , Ugrinova Iva , Pasheva Evdokia A. , Bakalova Adriana G. , Varbanov Hristo Pl. , Ferdinandov Dilyan V. , Ivanov Darvin Sl. , Konstantinov Spiro M.
Published: August 2009

An in vitro pharmacological evaluation of a novel dinuclear platinum complex ([KL2]2[Pt2I6], where L is 3‐amino‐5‐methyl‐5‐phenylhydantoin; Ad‐1) was carried out. The cytotoxicity of [KL2]2[Pt2I6] against human tumor cell lines was assessed using the MTT [‐3‐(4,5‐dimethylthiazol‐2‐Yl)‐2,5‐diphenyltetrazolium bromide] assay. The complex exerted concentration‐dependent cytotoxic effects that were comparable or even superior to that of cisplatin. Moreover, the novel complex retained significant activity against CaCo‐2 and Neuro‐2A cells, which showed primary resistance to cisplatin. As evidenced by the rising level of genomic DNA fragmentation following treatment with [KL2]2[Pt2I6], the cytotoxic effects are at least partly mediated by induction of apoptosis. The DNA binding of [KL2]2[Pt2I6] and cisplatin were assessed using a 40‐base fragment, whereby the present GG‐motif is the recognition sequence of the nuclease BamH1. The DNA platination was determined after BamH1 treatment, 5% PAGE, and ethidium bromide staining. Cisplatin completely inhibited the BamH1‐mediated fragmentation of the target DNA molecule. [KL2]2[Pt2I6] also significantly inhibited the fragmentation of the target DNA sequence. The platination induced by [KL2]2[Pt2I6] was better repaired by the nucleotide excision repair than the cisplatin lesions. As evidenced by electrophoresis mobility shift assay, the Ad‐1‐modified DNA was efficiently recognized and bound by the high mobility group box (HMGB)‐1 protein, a member of the HMG domain proteins, which implies that the latter are most probably important for the cytotoxicity mode of action of this agent.