ABSTRACT
The red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), is a common pest in rice mills. With limited information in the literature addressing T. castaneum in rice processing facilities, we examined the spatial and temporal distribution of T. castaneum inside and outside of three commercial rice milling facilities and one rice packaging plant from June 2012 to August 2014 using pheromone-baited dome traps. Each mill had very different population trends with fewer numbers collected in rough rice storage areas. T. castaneum were more commonly collected in processing areas. Beetle infestation at all the mills was evaluated using the threshold of mean beetle capture of 2.5 beetles per trap per 2 wk period. Trap captures were below threshold for all but one facility. Temperatures inside were ~1°C warmer than outside temperatures, with these temperature differences more noticeable during cool months (October-March). Higher numbers of T. castaneum were captured in 2012 in comparison to 2013, with higher beetle numbers observed during warmer (April-September) than cooler months. With variation in trap capture of T. castaneum occurring among all facilities, this study illustrates that having a monitoring program designed for each facility is important to help managers decide when and where to apply pest management tactics. The use of pheromone traps could provide information to mill managers to find locations within a mill that are most vulnerable to infestation by T. castaneum, and to assist with the timing of control interventions.
Subject(s)
Coleoptera , Oryza , Tribolium , Animals , Insect Control , PheromonesABSTRACT
Keratoconus(KC) is an ecstatic corneal disease leading to corneal-thinning and the formation of a cone-like cornea. Elevated lactate levels, increased oxidative stress, and myofibroblast formation have all been previously reported. In the current study, we assess the role of Quercetin on collagen secretion and myofibroblast formation in KC in vitro. Human corneal fibroblasts(HCFs) and human keratoconus cells(HKCs) were treated with a stable Vitamin C derivative and cultured for 4 weeks, stimulating formation of a self-assembled extracellular matrix. All samples were analyzed using Western blots and targeted tandem mass spectrometry. Our data showed that Quercetin significantly down regulates myofibroblast differentiation and fibrotic markers, such as α-smooth muscle actin (α-SMA) and Collagen III (Col III), in both HCFs and HKCs. Collagen III secretion was reduced 80% in both HCFs and HKCs following Quercetin treatment. Furthermore, Quercetin reduced lactate production by HKCs to normal HCF levels. Quercetin down regulated TGF-ßR2 and TGF-ß2 expression in HKCs suggesting a significant link to the TGF-ß pathway. These results assert that Quercetin is a key regulator of fibrotic markers and ECM assembly by modulating cellular metabolism and TGF-ß signaling. Our study suggests that Quercetin is a potential therapeutic for treatment of corneal dystrophies, such as KC.
Subject(s)
Extracellular Matrix/metabolism , Keratoconus/metabolism , Lactic Acid/biosynthesis , Quercetin/pharmacology , Cells, Cultured , Collagen/metabolism , Fibrosis , Humans , Keratoconus/drug therapy , Keratoconus/pathology , Metabolome , Metabolomics , Quercetin/chemistry , Signal Transduction , Transforming Growth Factor beta/metabolismABSTRACT
BACKGROUND: Intact frozen-thawed embryos have a greater potential than damaged embryos to establish successful pregnancies. This study aimed to determine whether elevated concentrations of sucrose during freezing would increase the proportion of patients with ≥ 50% of embryos intact after thawing (primary outcome), and improve clinical outcome. METHODS: In a two arm, parallel group, pragmatic trial, IVF/ICSI couples were randomized prospectively to have their supernumerary embryos frozen in a medium containing 0.1 M sucrose (control; n = 99) or 0.3 M sucrose (intervention; n = 102). RESULTS: More control (74/99) than intervention (63/102) couples had at least one embryo thawed (P = 0.07). Significantly more (P = 0.005) intervention (53/63) than control (45/74) couples had ≥ 50% of embryos intact. Freezing in a medium containing 0.3 M sucrose increased by 3.4-fold [95% confidence interval (CI) (1.45, 7.82)] the likelihood of a couple having ≥ 50% of their embryos intact. In the fresh cycle, live birth rate per transfer was similar in the control (35/95) and intervention (36/93) groups (P = 0.91). More control (19/63) than intervention (9/59) couples had a live birth after frozen embryo transfer (P = 0.08). When fresh and frozen cycles were combined, fewer intervention (n = 102) than control (n = 99) couples had at least one live birth (42 versus 53%). The difference in cumulative live birth rate was not significant [hazard ratio = 0.75, 95% CI (0.49, 1.13); P = 0.17]. CONCLUSIONS: Increasing the concentration of sucrose in the freezing medium improves embryo survival, but this is not reflected by increased cumulative birth rates. CLINICAL TRIALS REGISTRATION NUMBER: ISRCTN93314892.
Subject(s)
Cryopreservation/methods , Cryoprotective Agents/pharmacology , Embryo Transfer , Embryo, Mammalian/drug effects , Sucrose/administration & dosage , Female , Fertilization in Vitro , Humans , Live Birth , Pregnancy , Pregnancy Outcome , Sperm Injections, IntracytoplasmicABSTRACT
Gene transfer for cystic fibrosis (CF) airway disease has been hampered by the lung's innate refractivity to pathogen infection. We hypothesized that early intervention with an integrating gene transfer vector capable of transducing the lung via the lumen may be a successful therapeutic approach. An HIV-based lentiviral vector pseudotyped with the baculovirus gp64 envelope was applied to the fetal, neonatal or adult airways. Fetal intra-amniotic administration resulted in transduction of approximately 14% of airway epithelial cells, including both ciliated and non-ciliated epithelia of the upper, mid and lower airways; there was negligible alveolar or nasal transduction. Following neonatal intra-nasal administration we observed significant transduction of the airway epithelium (approximately 11%), although mainly in the distal lung, and substantial alveolar transduction. This expression was still detectable at 1 year after application. In the adult, the majority of transduction was restricted to the alveoli. In contrast, vesicular stomatitis virus glycoprotein pseudotyped virus transduced only alveoli after adult and neonatal application and no transduction was observed after fetal administration. Repeat administration did not increase transduction levels of the conducting airway epithelia. These data demonstrate that application at early developmental stages in conjunction with an appropriately pseudotyped virus provides efficient, high-level transgene expression in the murine lung. This may provide a modality for treatment for lung disease in CF.
Subject(s)
Baculoviridae/genetics , Genetic Therapy/methods , Genetic Vectors/administration & dosage , HIV/genetics , Transduction, Genetic/methods , Viral Envelope Proteins/genetics , Animals , Animals, Newborn , Cystic Fibrosis/metabolism , Cystic Fibrosis/therapy , Female , Gene Expression , Genetic Vectors/genetics , Green Fluorescent Proteins/analysis , Green Fluorescent Proteins/genetics , Immunohistochemistry , Luciferases/analysis , Luciferases/genetics , Lung/growth & development , Lung/metabolism , Male , Mice , Mice, Inbred Strains , Models, Animal , Time , TransgenesABSTRACT
BACKGROUND AND OBJECTIVES: The role of atrial myocardial dysfunction after cardioversion is unclear. In a comparison of patients after successful cardioversion from chronic atrial fibrillation (CAF) and normal controls, we sought to determine whether Doppler-derived atrial strain rate (A-sr) could be used to measure global left atrial function and whether A-sr was reduced in patients with CAF. METHODS: A-sr was measured from the basal septal, lateral, inferior and anterior atrial walls from the apical four-chamber and two-chamber views in 37 patients with CAF who had been cardioverted to sinus rhythm and followed up for 6 months, and in a cohort of 37 healthy people. Conventional measures of atrial function included peak transmitral A-wave velocity, A-wave velocity time integral, atrial fraction and the left atrial ejection fraction. Doppler tissue imaging was used to estimate atrial contraction velocity (A' velocity). In addition to amplitude parameters, the time to peak A-sr was measured from aortic valve closure. RESULTS: Immediately after cardioversion, A-sr in the CAF cohort (baseline) was significantly lower than in controls (mean (SD) -0.53 (0.31) v -1.6 (0.75) s(-1); p<0.001); the A-sr correlated with A' velocity (r = 0.63; p<0.001) in patients. Atrial function improved over time, with maximal change observed in the initial 4 weeks after cardioversion. The time to peak A-sr was increased in the CAF group compared with controls (0.55 (0.15) v 0.46 (0.12) s), but this failed to normalise over time. CONCLUSION: A-sr is a descriptor of atrial function, which is reduced after cardioversion from CAF and subsequently recovers.
Subject(s)
Atrial Fibrillation/therapy , Atrial Function, Left , Electric Countershock/adverse effects , Aged , Aged, 80 and over , Anthropometry , Chronic Disease , Echocardiography, Doppler , Female , Heart Atria/diagnostic imaging , Humans , Male , Middle Aged , Myocardial Contraction , Observer VariationABSTRACT
Lentivirus-based gene transfer has the potential to efficiently deliver DNA-based therapies into non-dividing epithelial cells of the airway for the treatment of lung diseases such as cystic fibrosis. However, significant barriers both to lung-specific gene transfer and to production of lentivirus vectors must be overcome before these vectors can be routinely used for applications to the lung. In this study, we investigated whether the ability to produce lentiviral vectors pseudotyped with fowl plague virus hemagglutinin (HA) could be improved by co-expression of influenza virus M2 in vector-producing cells. We found that M2 expression led to a 10-30-fold increase in production of HA-pseudotyped lentivirus vectors based upon equine infectious anemia virus (EIAV) or human immunodeficiency virus type 1 (HIV-1). Experiments using the M2 inhibitor amantadine and a drug-resistant mutant of M2 established that the ion channel activity of M2 was important for M2-dependent augmentation of vector production. Furthermore, the neuraminidase activity necessary for particle release from producer cells could also be incorporated into producer cells by co-expression of influenza NA cDNA. Lentiviral vectors pseudotyped with influenza envelope proteins were able to efficiently transduce via the apical membrane of polarized mouse tracheal cultures in vitro as well as mouse tracheal epithelia in vivo.
Subject(s)
Genetic Therapy/methods , Genetic Vectors/genetics , Lentivirus/genetics , Lung Diseases/therapy , Transduction, Genetic/methods , Viral Matrix Proteins/genetics , Animals , Fluorescent Antibody Technique , Genetic Engineering , Genetic Vectors/administration & dosage , Genotype , HIV-1/genetics , Hemagglutinins, Viral/genetics , Humans , Infectious Anemia Virus, Equine/genetics , Influenza A virus/genetics , Mice , Mice, Inbred C57BL , Rats , Trachea/virologyABSTRACT
Abnormalities in the control and execution of apoptosis are seen in many malignancies, including ovarian carcinoma. Many of these abnormalities involve the mitochondrial pathway of apoptosis, including overexpression of BIR-containing inhibitor of apoptosis protein (IAP) family proteins as well as dysregulated apoptosome function. We sought to stimulate the mitochondrial pathway of apoptosis by constructing a recombinant adenovirus encoding mature, processed Smac/DIABLO (Ad CMV tSmac), the second mitochondrial activator of caspases. Transfection of ovarian carcinoma cells with Ad CMV tSmac leads to increasing apoptosis in a dose-dependent manner. By contrast, transfection of IOSE397 immortalized normal ovarian surface epithelial cells does not cause apoptosis. We also show that the processed form of Smac is primarily expressed in the cytosol of ovarian carcinoma cells. Smac co-immunoprecipitates with both survivin and XIAP and stimulates survivin, but not XIAP, down-regulation. This down-regulation does not result from transcriptional changes, as determined by quantitative real-time PCR, but cycloheximide treatment indicates that survivin half-life is reduced from 6 to 2 h, which is secondary to ubiquitination and proteasomal degradation. RNA interference, however, suggests that survivin does not act to inhibit Smac-mediated apoptosis, which is confirmed by cotransfection with the phosphorylation mutant, survivin T34A. Finally, intraperitoneal delivery of Ad CMV tSmac increases median survival of mice bearing human ovarian carcinoma xenografts. We believe that expression of Smac/DIABLO can stimulate the intrinsic pathway of apoptosis in ovarian carcinoma without damaging normal ovarian tissue and therefore has therapeutic potential.
Subject(s)
Apoptosis/genetics , Carcinoma/metabolism , Carrier Proteins/metabolism , Microtubule-Associated Proteins/metabolism , Mitochondrial Proteins/metabolism , Ovarian Neoplasms/metabolism , Apoptosis Regulatory Proteins , Carcinoma/genetics , Carcinoma/therapy , Carrier Proteins/genetics , Carrier Proteins/pharmacology , Caspases/metabolism , Cell Line, Tumor , Dose-Response Relationship, Drug , Down-Regulation/genetics , Epithelial Cells/drug effects , Epithelial Cells/metabolism , Female , Genetic Therapy/methods , Genetic Vectors/genetics , Genetic Vectors/pharmacology , Humans , Inhibitor of Apoptosis Proteins , Injections, Intraperitoneal , Intracellular Signaling Peptides and Proteins , Microtubule-Associated Proteins/genetics , Mitochondria/genetics , Mitochondria/metabolism , Mitochondrial Proteins/genetics , Mitochondrial Proteins/pharmacology , Neoplasm Proteins , Ovarian Neoplasms/genetics , Ovarian Neoplasms/therapy , Proteasome Endopeptidase Complex/genetics , Protein Synthesis Inhibitors/pharmacology , Proteins/metabolism , Survival Rate , Survivin , Up-Regulation/genetics , X-Linked Inhibitor of Apoptosis ProteinABSTRACT
Flies (Diptera: Muscidae) that breed in faeces and other organic refuse (filth flies) have been implicated as vectors of pathogenic bacteria including Escherichia coli O157:H7, which cause haemorrhagic colitis in humans, and Campylobacter, which is the principal causative agent of human enteritis. The potential role of filth flies in the epidemiology of these pathogens in the United States was investigated by examining the prevalence of Campylobacter spp. and E. coli O157:H7 from two Arkansas turkey facilities. Polymerase chain reaction was conducted on DNA extractions of individual Musca domestica Linnaeus, Stomoxys calcitrans (Linnaeus), Hydrotaea aenescens (Wiedemann), Adia cinerella Fallen and turkey faecal samples using primers specific for E. coli H7, O157 and Campylobacter spp. Culturing verified that the flies were carrying viable Campylobacter spp. and E. coli O157:H7. Results from this study indicated that M. domestica, S. calcitrans, H. aenescens and Anthomyids are capable of carrying Campylobacter in North American poultry facilities and that the E. coli O157:H7 is carried by house flies and black dump flies associated with poultry. This PCR method provided a rapid and effective method to identify Campylobacter spp. and E. coli O157:H7 directly from individual filth flies.
Subject(s)
Campylobacter/genetics , Diptera/microbiology , Escherichia coli O157/genetics , Insect Vectors/microbiology , Turkeys/microbiology , Animals , Campylobacter/growth & development , Cattle , DNA, Bacterial/chemistry , DNA, Bacterial/genetics , Escherichia coli O157/growth & development , Feces/microbiology , Female , Food Microbiology , Male , Polymerase Chain Reaction , Poultry Diseases/microbiology , Poultry Diseases/transmission , Sequence Analysis, DNAABSTRACT
We report efficient operation of a KGd(WO(4))(2) Raman laser pumped by a small, 1 W, 532 nm laser module. By changing the output coupler and Raman crystal orientation, more than 8 wavelengths in the yellow-to-red spectral region were generated including 555 nm, 559 nm, 579 nm, 589 nm, 606 nm, 622 nm, 636 nm and 658 nm, ie., the first 4 Stokes orders on the two orthogonal high-gain Raman shifts of KGd(WO(4))(2). We have also demonstrated spectrally pure output (typically >90% pure) for selected Stokes order with output power up to 400 mW. High slope efficiency (up to 68%) and high beam quality (M(2)~1.5) of Stokes output are obtained even at the highest pump power.
ABSTRACT
We have constructed Ad CMV-Smac, a recombinant adenovirus encoding Smac/DIABLO, the recently described second mitochondrial activator of caspases. Transfection of ovarian carcinoma cells with Ad CMV-Smac at multiplicities of infection of 3-60 pfu/cell leads to increasing apoptosis in a dose-dependent manner. Western blot analysis confirms that Smac-induced apoptosis proceeds via a pathway mediated primarily by caspase-9 that can be inhibited by zLEHD-fmk and overexpression of the X-linked inhibitor of apoptosis protein (XIAP). In contrast, there is no cleavage of either caspase-8 or caspase-12. Ad CMV-Smac appears to induce apoptosis independently of cytochrome c release from mitochondria and is not inhibited by overexpression of Bcl-2. Ad CMV-Smac can combine with other proapoptotic factors, such as cisplatin, paclitaxel, and procaspase-3, to produce greater levels of apoptosis in transfected cells.
Subject(s)
Apoptosis/genetics , Carcinoma/enzymology , Carrier Proteins/metabolism , Caspases/metabolism , Gene Expression Regulation, Neoplastic/genetics , Mitochondrial Proteins/metabolism , Ovarian Neoplasms/enzymology , Antineoplastic Agents/pharmacology , Apoptosis/drug effects , Apoptosis Regulatory Proteins , Carcinoma/drug therapy , Carcinoma/genetics , Carrier Proteins/genetics , Caspase 3 , Caspase 9 , Caspases/genetics , Cytochrome c Group/metabolism , Enzyme Inhibitors/pharmacology , Enzyme Precursors/genetics , Enzyme Precursors/metabolism , Female , Genetic Vectors , Humans , Intracellular Signaling Peptides and Proteins , Mitochondrial Proteins/genetics , Ovarian Neoplasms/drug therapy , Ovarian Neoplasms/genetics , Proteins/genetics , Proteins/metabolism , Proto-Oncogene Proteins c-bcl-2/genetics , Proto-Oncogene Proteins c-bcl-2/metabolism , Recombinant Fusion Proteins , Tumor Cells, Cultured , X-Linked Inhibitor of Apoptosis ProteinABSTRACT
As much as 3 W of average power at 1064 nm from a diode-pumped Nd:YAG laser, Q switched at 4 kHz, was used to pump an external-resonator, crystalline Ba(NO3)2 Raman laser generating a maximum of 1.3-W output at the first Stokes wavelength of 1197 nm. The slope efficiency was 63% with respect to the fundamental power incident on the Ba(NO3)2 crystal. A reduction in the beam quality of the Stokes output from M2 approximately 1.4 at lower Stokes powers to M2 approximately 3.4 at higher powers is attributed to thermal loading of the Raman-active crystal.
ABSTRACT
BACKGROUND: Platelet-derived growth factor (PDGF) has been consistently implicated in the cell proliferation and extracellular matrix accumulation, which characterize progressive glomerular disease. In the present study, the effects of a potent and selective inhibitor of PDGF receptor tyrosine kinase, STI 571, were examined in vitro and in vivo. METHODS: Cultured mesangial cells were incubated with PDGF (50 ng/mL) and fibroblast growth factor-2 (FGF-2; 50 ng/mL) and treated with STI 571 (0.13 to 2.0 micromol/L). Experimental mesangial proliferative glomerulonephritis was induced in male Wistar rats with monoclonal OX-7, anti-rat Thy-1.1 antibody with rats randomized to receive either STI 571 (50 mg/kg intraperitoneally daily) or vehicle. Animals were examined six days later. RESULTS: In vitro, both PDGF and FGF-2 induced a threefold increase in mesangial cell 3H-thymidine incorporation. STI 571 reduced PDGF but not FGF-2-stimulated mesangial cell proliferation in a dose-dependent manner, with complete abolition at 0.4 micromol/L. In animals with Thy-1.1 glomerulonephritis, PDGF receptor tyrosine kinase blockade was associated with significant reductions in mesangial cell proliferation (P < 0.001), the number of activated (alpha-smooth muscle positive) mesangial cells, and glomerular type IV collagen deposition (P < 0.001). CONCLUSION: The amelioration of the pathological findings of experimental mesangial proliferative glomerulonephritis by blockade of PDGF receptor activity suggests the potential clinical utility of this approach as a therapeutic strategy in glomerular disease.
Subject(s)
Glomerular Mesangium/drug effects , Glomerulonephritis, Membranoproliferative/drug therapy , Platelet-Derived Growth Factor/antagonists & inhibitors , Platelet-Derived Growth Factor/physiology , Signal Transduction/drug effects , Animals , Benzamides , Cell Division/drug effects , Cell Line , Collagen/metabolism , Enzyme Inhibitors/pharmacology , Fibroblast Growth Factor 2/pharmacology , Glomerular Mesangium/pathology , Glomerulonephritis, Membranoproliferative/immunology , Glomerulonephritis, Membranoproliferative/metabolism , Glomerulonephritis, Membranoproliferative/pathology , Imatinib Mesylate , Kidney Glomerulus/metabolism , Kidney Glomerulus/pathology , Male , Piperazines/pharmacology , Platelet-Derived Growth Factor/pharmacology , Pyrimidines/pharmacology , Rats , Rats, Wistar , Receptors, Platelet-Derived Growth Factor/antagonists & inhibitors , Thy-1 Antigens/immunologyABSTRACT
We have previously shown that Actinobacillus actinomycetemcomitans produces an immunosuppressive factor that is encoded by the cdtB gene, which is homologous to a family of cytolethal distending toxins (Cdt) expressed by several gram-negative bacteria. In this study, we report that the cdt locus in A. actinomycetemcomitans is composed of five open reading frames, designated orf1, orf2, cdtA, cdtB, and cdtC. The deduced amino acid sequences of the five open reading frames are highly conserved among A. actinomycetemcomitans strains 652, Y4, 29522, and HK1651. There is also strong homology with the Cdt proteins of Haemophilus ducreyi (87-91%), but only partial homology with that of Campylobacter jejuni and Escherichia coli (29-48%). Analysis of A. actinomycetemcomitans mRNA by RT-PCR suggests that the two small open reading frames upstream of cdtA are coexpressed with cdtA, cdtB, and cdtC. We next utilized a series of plasmids that express various combinations of the cdt genes to determine their requirement for expression of immunoinhibitory activity. Cell extracts of E. coli transformed with each of the plasmids were tested for their capacity to induce G2 arrest in the cell cycle of PHA-activated human T cells. These experiments suggest that expression of cdtB alone is sufficient to induce G2 arrest in human T cells, but do not exclude the possibility that cdtC also contributes to cell cycle arrest. The implications of our results with respect to the function of the individual Cdt proteins are discussed.
Subject(s)
Aggregatibacter actinomycetemcomitans/immunology , Bacterial Toxins/genetics , G2 Phase/immunology , Gene Expression Regulation, Bacterial/immunology , Genes, Bacterial/immunology , Growth Inhibitors/genetics , Operon/immunology , T-Lymphocytes/immunology , Aggregatibacter actinomycetemcomitans/genetics , Bacterial Proteins/biosynthesis , Bacterial Proteins/genetics , Bacterial Proteins/immunology , Bacterial Proteins/toxicity , Bacterial Toxins/biosynthesis , Bacterial Toxins/immunology , Bacterial Toxins/toxicity , Cells, Cultured , G2 Phase/genetics , Growth Inhibitors/biosynthesis , Growth Inhibitors/immunology , Growth Inhibitors/toxicity , Humans , Immunosuppressive Agents/immunology , Immunosuppressive Agents/toxicity , Molecular Sequence Data , Multigene Family/immunology , T-Lymphocytes/cytology , T-Lymphocytes/microbiologyABSTRACT
We have investigated the use of polycations to increase adenovirus-mediated expression of transgenic protein to the biliary epithelia with a view to gene therapy for hepatobiliary disease in CF. We have shown that adenovirus carrying the beta-galactosidase transgene transfect both human and mouse biliary epithelia in primary culture and that in both instances adenovirus transfection can be significantly increased by co-complexing with polycation. In vivo administration of 1 x 109 p.f.u. adenovirus co-complexed with the polyamine polyethyenimine (PEI) into the mouse biliary duct leads to >80% positively stained biliary epithelia while adenovirus alone at the same titre infected <5% biliary epithelia. We suggest that the use of low titre polycation enhanced adenoviral delivery to the biliary tree of CF patients could be of therapeutic significance. As a prelude to an extensive in vivo functional investigation in CF null mice we have shown that Ad5/polycation complexes deliver functional CFTR to non-CFTR expressing cells in vitro more efficiently than Ad5 alone.
Subject(s)
Adenoviridae/genetics , Cystic Fibrosis Transmembrane Conductance Regulator/genetics , Cystic Fibrosis/therapy , Genetic Therapy/methods , Genetic Vectors/administration & dosage , Transfection/methods , Animals , Cations , Cell Line , Culture Techniques , Epithelium , Gallbladder , Humans , MiceABSTRACT
We present two weak lensing reconstructions of the nearby (zcl=0.055) merging cluster Abell 3667, based on observations taken approximately 1 yr apart under different seeing conditions. This is the lowest redshift cluster with a weak lensing mass reconstruction to date. The reproducibility of features in the two mass maps demonstrates that weak lensing studies of low-redshift clusters are feasible. These data constitute the first results from an X-ray luminosity-selected weak lensing survey of 19 low-redshift (z<0.1) southern clusters.
ABSTRACT
The Robotic Optical Transient Search Experiment (ROTSE) seeks to measure simultaneous and early afterglow optical emission from gamma-ray bursts (GRBs). A search for optical counterparts to six GRBs with localization errors of 1 deg2 or better produced no detections. The earliest limiting sensitivity is mROTSE>13.1 at 10.85 s (5 s exposure) after the gamma-ray rise, and the best limit is mROTSE>16.0 at 62 minutes (897 s exposure). These are the most stringent limits obtained for the GRB optical counterpart brightness in the first hour after the burst. Consideration of the gamma-ray fluence and peak flux for these bursts and for GRB 990123 indicates that there is not a strong positive correlation between optical flux and gamma-ray emission.
ABSTRACT
Over a 4 year period, 1991 to 1994, 420 patients with acute bacterial meningitis were admitted to a tertiary urban hospital in The Gambia. Organisms were isolated from the cerebrospinal fluid in 64 per cent of cases. In the neonatal period Streptococcus pneumoniae was the single most common organism isolated. Amongst infants and children the two major pathogens were Haemophilus influenzae and S. pneumoniae. In the first year of life, children with S. pneumoniae meningitis were younger than those with H. influenzae infection (median age 3 months versus 6 months, p < 0.00003) and they had a higher case fatality rate (37 per cent versus 17 per cent, p = 0.002). In view of the high case fatality rate, there is a need to review overall case management. This will include a review of more effective antibiotics, the possible role of dexamethasone, and the inclusion of efficacious vaccines against H. influenzae and S. pneumoniae disease.
Subject(s)
Meningitis, Bacterial/epidemiology , Meningitis, Bacterial/microbiology , Acute Disease , Child, Preschool , Gambia/epidemiology , Humans , Infant , Infant, Newborn , Meningitis, Bacterial/prevention & control , Mortality , Retrospective Studies , Seasons , Statistics, NonparametricABSTRACT
We have previously shown that Actinobacillus actinomycetecomitans produces an immunosuppressive factor (ISF) capable of impairing human lymphocyte function by perturbing cell cycle progression. We now report that ISF is the product of the cdtB gene, one of three genes encoding the family of cytolethal distending toxins (Cdt). The ISF polypeptide exhibits >/=95% identity with Hemophilus ducreyi CdtB protein and =60% homology with Escherichia coli or Campylobacter jejuni CdtB. Pretreatment of PHA-activated lymphocytes with 5-25 ng ISF results in G2 arrest of CD4+ and CD8+ T cells. Similarly, treatment of HeLa cells results in G2 arrest and cell elongation and distension. However, lymphocytes are at least 5 times more sensitive to ISF than HeLa cells and do not undergo the elongation and distension that characterizes interactions of Cdts with cell lines. ISF-treated lymphocytes express normal cyclin A and B1 levels, but contain reduced levels of cell cycle-dependent kinase-1 (Cdk1). Additionally, the majority of Cdk1 is in the hyperphosphorylated, inactive, form. In contrast, PHA-induced G2 cells contain elevated levels of the hypophosphorylated, active Cdk1. Failure of ISF-treated cells to dephosphorylate Cdk1 is not associated with decreased availability of Cdc25. These studies suggest that the CdtB protein alone is capable of inducing G2 arrest in lymphocytes and cell cycle arrest, elongation, and distension of HeLa cells. Our studies also suggest that lymphocytes may be primary targets for A. actinomycetemcomitans CdtB (ISF) and possibly for other Cdt family members as well. Thus, Cdts may function to impair host immunity and contribute to the pathogenesis of disease associated with Cdt-producing organisms.