Gold Standard Cholera Diagnostics Are Tarnished by Lytic Bacteriophage and Antibiotics.

A fundamental, clinical, and scientific concern is how lytic bacteriophage, as well as antibiotics, impact diagnostic positivity. Cholera was chosen as a model disease to investigate this important question, because cholera outbreaks enable large enrollment, field methods are well established, and the predatory relationship between lytic bacteriophage and the etiologic agent Vibrio cholerae share commonalities across bacterial taxa. Patients with diarrheal disease were enrolled at two remote hospitals in Bangladesh. Diagnostic performance was assessed as a function of lytic bacteriophage detection and exposure to the first-line antibiotic azithromycin, detected in stool samples by mass spectrometry. Among diarrheal samples positive by nanoliter quantitative PCR (qPCR) for V. cholerae (n = 78/849), the odds that a rapid diagnostic test (RDT) or qPCR was positive was reduced by 89% (odds ratio [OR], 0.108; 95% confidence interval [CI], 0.002 to 0.872) and 87% (OR, 0.130; 95% CI, 0.022 to 0.649), respectively, when lytic bacteriophage were detected. The odds that an RDT or qPCR was positive was reduced by more than 99% (OR, 0.00; 95% CI, 0.00 to 0.28) and 89% (OR, 0.11; 95% CI, 0.03 to 0.44), respectively, when azithromycin was detected. Analysis of additional samples from South Sudan found similar phage effects on RDTs; antibiotics were not assayed. Cholera burden estimates may improve by accommodating for the negative effects of lytic bacteriophage and antibiotic exposure on diagnostic positivity. One accommodation is using bacteriophage detection as a proxy for pathogen detection. These findings have relevance for other diagnostic settings where bacterial pathogens are vulnerable to lytic bacteriophage predation.

Curative rectal cancer surgery in a low-volume hospital: a quality assessment.

AIMS: Hospital volume or caseload is often used as a surrogate measure for quality of care in rectal cancer treatment. The aim of this study was to assess outcome in a low-volume hospital and secondly to examine the impact of surgeon volume on the results. METHODS: A retrospective review of 131 patients' charts identified 102 patients receiving apparently curative resections for rectal cancer in the period 1993-2002. Our study population did not differ significantly from the national average except for shift towards more advanced Dukes stage (p=0.00) and a higher rate of node positive patients at time of diagnosis (p=0.00). RESULTS: There were no significant differences from the national outcome results, neither in perioperative mortality or complications, nor 5-year survival or local recurrences. Thirteen different on-staff surgeons performed rectal cancer surgery in our hospital in the decade, and median annual caseload was four. We detect a difference in 5-year survival when grouping the surgeons by annual caseload, but the significance is inconclusive. It is, however, interesting that in 85% of the resections, two or more certified gastrointestinal surgeons with specific training were involved. A relatively high number (9%) of discrepancies between the Norwegian Rectal Cancer Registry (NRCR) database and the local hospital database were identified. CONCLUSION: Adequate results for surgical outcome can be achieved in a low-volume hospital. Surgeon volume showed inconclusive impact for our results of outcome. A local quality initiative is justified in addition to national registries.

In vitro test-system for chemo- and thermosensitivity: an analysis of survival fractions and cell-cycle distributions in human Ewing's sarcomas as a modelfor tumors in pediatric oncology.

BACKGROUND: Tumor cell resistance to anticancer drugs is the primary reason for treatment failure in childhood cancer. Resistance can exist at the onset of treatment or can become clinically apparent under selective pressure of drug exposure. In vitro predictive tests are important for the experimental study of drug resistance. Although in vitro studies appear to be fairly good for predicting drug resistance, they are rarely used in the routine management of individual cases. An exception that proves the rule is the MTT- (3-[4,5-dimethylthiazol-2-yl]-2,5- diphenyltetrazoliumbromide) assay in children with acute lymphoblastic leukemias (ALL), which can be correlated with the clinical outcome in this group of patients. In the present study we used a predictive test-system to evaluate the synergistic cytotoxic effects of chemotherapy +/- hyperthermia with respect to cell cycle disturbance. METHODS: As a tumor model two well defined human Ewing's sarcoma cell lines VH64 and SK-ES-1 were treated for 1 h with cis-diamminedichloroplatinum II (cDDP) (0.1, 0.5, 1, 3, 5 micro g/ml) or 4'-demethyl-epipodophyllotoxin-5-(4,6-0-)-ethylidene-beta-D-glycopyranoside (VP-16) (1, 5, 10, 20, 50 micro g/ml) +/- hyperthermia (42 degrees C, 43 degrees C); control: 37 degrees C, without chemotherapy. Cell survival was tested using the XTT- (2,3-bis[2-Methoxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide) assay. Assay conditions were optimized for each tumor cell line, extinction was measured 72 h post treatment at 450 nm in an ELISA-reader. Cell cycle fractions (G0/G1-, S-, G2/M-phase) were determined immediately, 12 h and 24 h after treatment by labeling proliferating tumor cells with bromodeoxyuridine (BrdU) and measuring DNA-content with propidium-iodide (PI) and analyzed by flow cytometry. RESULTS: Survival fractions: Hyperthermia alone at 43 degrees C reduced tumor cell survival to 51 % in SK-ES-1 and 74 % in VH64. cDDP (5 micro g/ml): reduction of survival fraction to 23 % in SK-ES-1 and 33 % in VH64. cDDP (5 micro g/ml) + hyperthermia (43 degrees C): enhanced reduction of tumor cell survival compared to 37 degrees C to 11 % in SK-ES-1 and 8 % in VH64. VP-16 (50 micro g/ml): survival fraction of 18 % in SK-ES-1 and of 31 % in VH64. In contrast to cDDP, chemosensitivity of the tumor cells to VP-16 could not synergistically be enhanced by using hyperthermia. Cell cycle analysis: Hyperthermia alone at 43 degrees C induced an accumulation in G2/M and a slight reduction in G0/G1-phase 24 h after treatment, whereas the S-phase was not markedly affected. cDDP (5 micro g/ml) alone led to a prominent S-phase arrest and a G0/G1 decrease 24 h after treatment. Simultaneous application of cDDP (5 micro g/ml) + hyperthermia (43 degrees C) however significantly reduced S-phase cells. VP-16 (50 micro g/ml) alone induced a temporary S-phase arrest 12 h after treatment and a delayed G2/M-arrest after 24 h. Additional hyperthermia at 43 degrees C did not show further effects on VP-16 induced cell cycle disturbances. CONCLUSIONS: Test-system discloses treatment-specific alterations in tumor cell survival and cell cycle distribution, e. g. synergistic enhancement of cDDP cytotoxicity by heat application, which might predict chemo- and thermosensitivity.

Mitochondrial localization and temporal expression of the Drosophila melanogaster DnaJ homologous tumor suppressor Tid50.

The Drosophila melanogaster tumor suppressor gene lethal(2)tumorous imaginal discs (tid) was identified as a homolog of all dnaJ-like genes known to date which have been well preserved in evolution. Homozygous D. melanogaster l(2)tid mutants l(2)tid1, l(2)tid2 and l(2)tid3 are characterized by neoplastic transformation of the adult integumental primordia, the imaginal discs, and the death at the time of puparium formation. The first part of this study is concerned with the identification and subcellular localization of the l(2)tid-encoded protein, Tid50. The second part examines its tissue specific expression during wild-type development and in tumorous imaginal discs. To specify the function(s) of the Tid50 protein polyclonal rabbit antibodies directed against various domains of it were generated and used for staining of Western blots and whole-mounts and paraffin sections of various tissues isolated from wild-type and mutant tumor-developing animals. To identify the mutational events leading in homozygous l(2)tid mutants to abnormal expression level of l(2)tid-encoded RNA and protein, the mutant gene was isolated from homozygous l(2)tid1 and l(2)tid2 animals and sequenced.

Gene within gene configuration and expression of the Drosophila melanogaster genes lethal(2) neighbour of tid [l(2)not] and lethal(2) relative of tid[l(2)rot].

In this paper, we describe the structure and temporal expression pattern of the Drosophila melanogaster genes l(2)not and l(2)rot located at locus 59F5 vis à vis the tumor suppressor gene l(2)tid described previously and exhibiting a gene within gene configuration. The l(2)not protein coding region, 1530 nt, is divided into two exons by an intron, 2645 nt, harboring the genes l(2)rot, co-transcribed from the same DNA strand, and l(2)tid, co-transcribed from the opposite DNA strand, located vis à vis. To determine proteins encoded by the genes described in this study polyclonal rabbit antibodies (Ab), anti-Not and anti-Rot, were generated. Immunostaining of developmental Western blots with the anti-Not Ab resulted in the identification of a 45-kDa protein, Not45, which is smaller than the Not56 protein predicted from the sequence. Its localization in endoplasmic reticulum (ER) was established by immunoelectron microscopy of Drosophila melanogaster Schneider 2 cells. Not45 shows significant homology to yeast ALG3 protein acting as a dolichol mannosyltransferase in the asparagine-linked glycosylation. It is synthesized ubiquitously throughout embryonic life. The protein predicted from the l(2)rot sequence, Rot57, shows a homology to the NS2B protein of the yellow fever virus1 (yefv1). The results of l(2)rot RNA analysis by developmental Northern blot and by in situ RNA localization, as well as the results of the protein analysis via Western blot and immunohistochemistry suggest that l(2)rot is transcribed but not translated. Since RNAs encoded by the genes l(2)tid and l(2)rot are complementary and l(2)rot is presumably not translated we performed preliminary experiments on the function of the l(2)rot RNA as a natural antisense RNA (asRNA) regulator of l(2)tid expression, expressed in the same temporal and spatial manner as the l(2)tid- and l(2)not RNA. l(2)tid knock-out by antisense RNA yielded late embryonic lethality resulting from multiple morphogenetic defects.

Sequence, molecular organization and products of the Drosophila virilis homologs of the D. melanogaster nested genes lethal(2) tumorous imaginal discs [1(2)tid] and lethal(2) neighbour of tid [1(2)not].

In this study, we describe the isolation of the Drosophila virilis (Dvir) 6201-bp genomic fragment homologous to a 7047-bp genomic region of D. melanogaster (Dmel) that harbors the nested genes lethal(2) tumorous imaginal discs (l(2)tid), lethal(2) neighbour of tid (l(2)not) and lethal(2) relative of tid (l(2)rot). The isolated fragment, which maps at the cytogenetic position 50A5 on chromosome 5, carries the Dvir homologs of the Dmel genes l(2)tid and l(2)not. In both cases, the interspecific comparison of the determined sequences reveals a high homology regarding the protein coding regions and a high degree of evolutionary divergence concerning the intronic parts of the genes. In the two distantly related species, the particular gene within gene arrangement of the two genes is conserved, namely, Dvir tid is located in the intron of Dvir not, on the non-coding DNA strand. Interestingly, the Dvir homolog of the Dmel l(2)rot gene residing in the l(2)not intron on its coding strand, opposite l(2)tid, is not present in the 6201-bp genomic fragment. The protein predicted from the Dvir tid sequence, Dvir Tid58, exhibits 76.5% identity with the putative Tid56 protein of Dmel. The putative Dvir Not58 protein shows 71% identity with its Dmel homolog Not56. The developmental transcript and protein patterns, as well as the characteristics of the protein products encoded by the genes Dvir tid and Dvir not are similar to those identified for their Dmel homologs.

Identification of a novel Drosophila melanogaster heat-shock gene, lethal(2)denticleless [l(2)dtl], coding for an 83-kDa protein.

In this study, we describe the identification of a novel Drosophila melanogaster (Dm) gene, l(2)dtl, characterized by elevated expression under heat-shock (HS) conditions. It encodes a protein of 83 kDa with no homology to known members of the HSP90 family and other proteins. Gene l(2)dtl is located on the right arm of the second chromosome at locus 59F5, close to the tumor suppressor gene l(2)tid, a homolog of the dnaJ encoding a chaperone strongly conserved in evolution. In the following, we present the sequence of l(2)dtl, the putative protein it encodes, and its molecular localization in a closely interspaced gene cluster consisting of at least four nested genes spanning an approximately 10-kb genomic interval. Furthermore, we present the temporal expression of l(2)dtl in the wild type under normal and HS conditions, and describe the isolation and the phenotype of eight embryonic lethal l(2)dtl mutants.

Distribution, expression, and long-range mapping of legiolysin gene (lly)-specific DNA sequences in legionellae.

The legiolysin gene (lly) cloned from Legionella pneumophila Philadelphia 1 confers the phenotypes of hemolysis and browning of the culture medium. An internal lly-specific DNA probe was used in Southern hybridizations for the detection of lly-specific DNA in the genomes of legionellae and other gram-negative pathogenic bacteria. Under conditions of high stringency, the lly DNA probe specifically reacted with DNA fragments from L. pneumophila isolates; by reducing stringency, hybridization was also observed for all other Legionella strains tested. No hybridization occurred with DNAs isolated from bacteria of other genera. The lly gene was mapped by pulsed-field gel electrophoresis to the respective genomic NotI fragments of Legionella isolates. By using antilegiolysin monospecific polyclonal antibodies in Western blots (immunoblots), Lly proteins could be detected only in L. pneumophila isolates.

Characterization of legiolysin (lly), responsible for haemolytic activity, colour production and fluorescence of Legionella pneumophila.

A genomic library of Legionella pneumophila, the causative agent of Legionnaires' disease in humans was constructed in Escherichia coli K12 and the recombinant clones were tested for haemolysis and other phenotypic properties. Seven clones were identified which were able to confer haemolysis of human, sheep, and canine erythrocytes but which were unable to mediate proteolytic activities or cytotoxic effects on CHO- or Vero cells. Clones that exhibited this haemolytic property were also able to produce a brown colour and a yellow-green fluorescence activity detected on M9 plates containing tyrosine. The genetic determinant encoding these properties, termed legiolysin (lly) was mapped by Tn1000 mutagenesis and by subcloning experiments. Southern hybridization with an lly-specific gene probe showed that this determinant is part of the genome of L. pneumophila but is not identical to a protease gene of L. pneumophila which also mediates haemolysis. Minicell analysis of lly-specific plasmids exhibited a protein of 39 kDa. Polyclonal antibodies generated against a LacZ-Lly hybrid protein also recognized a 39 kDa protein produced either by the recombinant legiolysin-positive E. coli K12 clones or by L. pneumophila wild-type strains.