Rare case of occupational pulmonary hemorrhage in a firefighter.

Alveolar hemorrhage associated with physical exertion, known as exercise-induced pulmonary hemorrhage (EIPH), is a rare condition linked to strenuous exertion. This can be an unusual form of respiratory and occupational illness. We present the case of a healthy firefighter who developed fatal pulmonary hemorrhage after participating in a strenuous physical training exercise regimen. This case represents a severe presentation of EIPH, which results from the disruption of the pulmonary blood-gas barrier as a result of strenuous exertion. Clinicians caring for those in vocations and recreation involving extremely vigorous exercise should be aware that such activities can cause EIPH.

The flagellar master operon flhDC is a pleiotropic regulator involved in motility and virulence of the fish pathogen Yersinia ruckeri.

AIMS: To investigate the function of the master flagellar operon flhDC in the fish pathogen Yersinia ruckeri and compare the effect of a constructed flhD mutation to a naturally occurring fliR mutation causing loss-of-motility in emergent biotype 2 (BT2) strains. METHODS AND RESULTS: Yersinia ruckeri flhD and fliR mutants were constructed in a motile strain. Both mutations caused loss-of-motility, ablation of flagellin synthesis and phospholipase secretion, similar to naturally occurring BT2 strains. Transcriptome analysis confirmed flhDC regulation of flagellar, chemotaxis and phospholipase loci as well as other genes of diverse function. The flhD mutation confers a competitive advantage within the fish host when compared with its parent strain, while this advantage was not seen with the naturally occurring fliR mutation. CONCLUSIONS: An intact flhD is necessary for expression of the flagellar secretion system as well as other diverse loci, consistent with a role for flhD as a pleiotropic regulator. The maintenance of the flhD locus in Y. ruckeri strains suggests its importance for aspects of Y. ruckeri biology other than virulence, since the flhD mutation conferred a competitive advantage during experimental challenge of rainbow trout. SIGNIFICANCE AND IMPACT OF THE STUDY: Yersinia ruckeri is the causative agent of enteric red mouth disease, an invasive septicaemia that affects farmed salmonid fish species. Disease outbreaks can cause severe economic losses in aquaculture. BT2 variants, which have independently emerged worldwide, are an increasing threat to farmed fish production. Knowledge of mechanisms involved in virulence, conserved functions and gene regulation among strains may be exploited for the development of novel disease control strategies to prevent pathogen growth or virulence phenotypes within aquaculture.

Diagnostic tools for rapid detection and quantification of Weissella ceti NC36 infections in rainbow trout.

Weissellosis of rainbow trout is caused by the Gram-positive bacteria Weissella ceti and has been reported in China, Brazil and the United States. This disease can result in high mortality in market-sized fish and thus can cause significant economic loss. Thus far, phenotypic characterization and 16S rRNA sequencing have been used to confirm a Weissellosis diagnosis. Here, we present the development of PCR-based diagnostic tools for the rapid identification and quantification of W. ceti within bacteriological culture and infected tissues. A duplex PCR, which amplifies both genus- and strain-specific targets, positively identifies isolates as W. ceti NC36. A qPCR assay was also developed to quantify pathogen load from infected tissues, using a W. ceti NC36 unique locus. A proof of concept study was performed to demonstrate that quantification using traditional plate count methods and qPCR were significantly correlated when assessed from infected brain and spleen tissue. These tools were also used to confirm diagnosis of Weissellosis in a commercial rainbow trout farm during an outbreak investigation. These are the first diagnostic tools developed for identification and quantification of W. ceti infection within rainbow trout, contributing to rapid Weissellosis diagnosis, enhanced pathogen surveillance and epidemiological studies.

Intragenomic heterogeneity in the 16S rRNA genes of Flavobacterium columnare and standard protocol for genomovar assignment.

Genetic variability in 16S rRNA gene sequences has been demonstrated among isolates of Flavobacterium columnare, and a restriction fragment length polymorphism (RFLP) assay is available for genetic typing of this important fish pathogen. Interpretation of restriction patterns can be difficult due to the lack of a formal description of the expected number and sizes of DNA fragments generated for each of the described genomovars. In this study, partial 16S rRNA gene sequences (ca. 1250-bp fragment) from isolates representing each described genomovar and isolates generating unique restriction patterns were cloned and sequenced. The results demonstrated that some isolates contained up to three different 16S rRNA genes whose sequences generate different RFLP patterns due to intragenomic heterogeneity within HaeIII restriction sites. The occurrence of HaeIII restriction sites within the portion of the 16S rRNA gene used for typing the F. columnare isolates and intragenomic heterogeneity within these sites explained the restriction patterns observed following RFLP analyses. This research provides a standard protocol for typing isolates of F. columnare by RFLP and a formal description of the expected restriction patterns for the previously described genomovars I, II, II-B and III. Additionally, we describe a new genomovar, I/II.

Rapid genotyping assays for the identification and differentiation of Yersinia ruckeri biotype 2 strains.

AIMS: To establish PCR-based assays for the rapid identification and differentiation of each of four known biotype 2 (BT2) phenotype-causing alleles in Yersinia ruckeri strains currently circulating in Europe and the United States. METHODS AND RESULTS: Novel assays were developed relying on detection of mutant allele-specific changes in restriction enzyme cleavage sites within targeted PCR products. The developed assays were validated against isolates previously genotyped by DNA sequencing. CONCLUSIONS: The described methods were specific, rapid and simple to perform and interpret. SIGNIFICANCE AND IMPACT OF THE STUDY: The developed genotyping assays provide a valuable tool for identification and differentiation of specific BT2 strains of Y. ruckeri. These assays will be critical for the design and validation of new vaccines or other measures meant to control BT2 strains.

Evidence of major genes affecting resistance to bacterial cold water disease in rainbow trout using Bayesian methods of segregation analysis.

Bacterial cold water disease (BCWD) causes significant economic loss in salmonid aquaculture. We previously detected genetic variation for BCWD resistance in our rainbow trout population, and a family-based selection program to improve resistance was initiated at the National Center for Cool and Cold Water Aquaculture (NCCCWA). This study investigated evidence of major trait loci affecting BCWD resistance using only phenotypic data (without using genetic markers) and Bayesian methods of segregation analysis (BMSA). A total of 10,603 juvenile fish from 101 full-sib families corresponding to 3 generations (2005, 2007, and 2009 hatch years) of the NCCCWA population were challenged by intraperitoneal injection with Flavobacterium psychrophilum, the bacterium that causes BCWD. The results from single- and multiple-QTL models of BMSA suggest that 6 to 10 QTL explaining 83 to 89% of phenotypic variance with either codominant or dominant disease-resistant alleles plus polygenic effects may underlie the genetic architecture of BCWD resistance. This study also highlights the importance of polygenic background effects in the genetic variation of BCWD resistance. The polygenic heritability on the observed scale of survival status is slightly larger than that previously reported for rainbow trout BCWD resistance. These findings provide the basis for designing informative crosses for QTL mapping and carrying out genome scans for QTL affecting BCWD resistance in rainbow trout.

Myoglobin production in emperor penguins.

Increased oxygen storage is essential to the diving capacities of marine mammals and seabirds. However, the molecular mechanisms underlying this adaptation are unknown. Myoglobin (Mb) and Mb mRNA concentrations were analyzed in emperor penguin (Aptenodytes forsteri) adults and chicks with spectrophotometric and RNase protection assays to evaluate production of their large Mb-bound O(2) stores. Mean pectoral Mb concentration and Mb mRNA content increased throughout the pre-fledging period and were 15-fold and 3-fold greater, respectively, in adults than in 3.5 month old chicks. Mean Mb concentration in 5.9 month old juveniles was 2.7+/-0.4 g 100 g(-1) muscle (44% that of wild adults), and in adults that had been captive all their lives it was 3.7+/-0.1 g 100 g(-1) muscle. The Mb and Mb mRNA data are consistent with regulation of Mb production at the level of transcription as in other animals. Significant Mb and Mb mRNA production occurred in chicks and young juveniles even without any diving activity. The further increase in adult Mb concentrations appears to require the exercise/hypoxia of diving because Mb concentration in captive, non-diving adults only reached 60% of that of wild adults. The much greater relative increase in Mb concentration than in Mb mRNA content between young chicks and adults suggests that there is not a simple 1:1 relationship between Mb mRNA content and Mb concentration. Nutritional limitation in young chicks and post-transcriptional regulation of Mb concentration may also be involved.

Response to selection for bacterial cold water disease resistance in rainbow trout.

A family-based selection program was initiated at the National Center for Cool and Cold Water Aquaculture in 2005 to improve resistance to bacterial cold water disease (BCWD) in rainbow trout. The objective of this study was to estimate response to 2 generations of selection. A total of 14,841 juvenile fish (BW = 3.1 g; SD = 1.1 g) from 230 full-sib families and 3 randomly mated control lines were challenged intraperitoneally with Flavobacterium psychrophilum, the bacterium that causes BCWD, and mortalities were observed for 21 d. Selection was applied to family EBV derived from a proportional-hazards frailty (animal) model while constraining rate of inbreeding to

Rainbow trout resistance to bacterial cold-water disease is moderately heritable and is not adversely correlated with growth.

The objectives of this study were to estimate the heritabilities for and genetic correlations among resistance to bacterial cold-water disease and growth traits in a population of rainbow trout (Oncorhynchus mykiss). Bacterial cold-water disease, a chronic disease of rainbow trout, is caused by Flavobacterium psychrophilum. This bacterium also causes acute losses in young fish, known as rainbow trout fry syndrome. Selective breeding for increased disease resistance is a promising strategy that has not been widely used in aquaculture. At the same time, improving growth performance is critical for efficient production. At the National Center for Cool and Cold Water Aquaculture, reducing the negative impact of diseases on rainbow trout culture and improving growth performance are primary objectives. In 2005, when fish averaged 2.4 g, 71 full-sib families were challenged with F. psychrophilum and evaluated for 21 d. Overall survival was 29.3% and family rates of survival varied from 1.5 to 72.5%. Heritability of postchallenge survival, an indicator of disease resistance, was estimated to be 0.35 +/- 0.09. Body weights at 9 and 12 mo posthatch and growth rate from 9 to 12 mo were evaluated on siblings of the fish in the disease challenge study. Growth traits were moderately heritable, from 0.32 for growth rate to 0.61 for 12-mo BW. Genetic and phenotypic correlations between growth traits and resistance to bacterial cold-water disease were not different from zero. These results suggest that genetic improvement can be made simultaneously for growth and bacterial cold-water disease resistance in rainbow trout by using selective breeding.

Detection of flat lesions in the colon with CT colonography.

BACKGROUND: We investigated whether flat lesions of the colon could be detected on computed tomographic colonography (CTC). METHODS: CTC and conventional colonoscopy were performed on 547 consecutive patients. A subset of 22 polyps was described as flat on colonoscopy (n = 16) or CTC (n = 6) and are the basis of this report. CTC was performed with a standard technique (5-mm collimation, 3-mm reconstruction intervals). Patients were scanned in supine and prone positions. Examinations were randomly assigned and reviewed in a blinded fashion by two of three radiologists. Prospective interpretations were recorded. All patients had conventional colonoscopy, which served as the gold standard. RESULTS: Twenty-two flat lesions ranging from 0.4 to 3.5 cm were histologically classified as adenomatous (n = 8) or hyperplastic (n = 14). The sensitivities for detecting all flat lesions and flat adenomas by each reviewer were 43% and 100%, 65% and 100%, and 15% and 13%, respectively. "Double reading" resulted in detection of 68% of all lesions and 100% of adenomas. Of the seven hyperplastic polyps missed by both reviewers, four were identified retrospectively. CONCLUSION: Flat lesions of the colon represent an important source of false negative CTC examinations. Awareness of their morphology can assist radiologists in finding most of these challenging lesions.

CT colonography: single- versus multi-detector row imaging.

PURPOSE: To compare respiratory artifacts, colonic distention, and polyp detection at computed tomographic (CT) colonography by using single- and multi-detector row helical CT systems. MATERIALS AND METHODS: A total of 237 consecutive patients received subcutaneously administered glucagon and underwent prone and supine CT colonography with single-detector row CT (n = 77) and multi-detector row CT (n = 160), followed by colonoscopy. Examination results were graded for colonic distention, respiratory artifacts, and polyp depiction by two radiologists working independently. RESULTS: Suboptimal colonic distention was significantly more common with single-detector row CT and was present in at least one segment in 52% (40 of 77 patients) of examinations versus only 19% (30 of 160 patients) with multi-detector row CT (P <.001). Mild respiratory artifacts were present in 61% (47 of 77 patients) of single-detector row CT examinations versus only 16% (26 of 160 patients) of multi-detector row CT examinations (P <.001). Depiction of polyps larger than 10 mm was 89% (eight of nine polyps) for single-detector row CT and 80% (eight of 10 polyps) for multi-detector row CT (P >.05). CONCLUSION: CT colonography performed with multi-detector row CT significantly improved the demonstration of colonic distention and depicted fewer respiratory artifacts compared with single-detector row CT. No significant differences in the depiction of polyps larger than 10 mm were demonstrated between single- and multi-detector row CT for a small number of polyps. Studies with a larger prevalence of clinically important polyps are needed for further evaluation of differences in polyp detection.

The overlapping angB and angG genes are encoded within the trans-acting factor region of the virulence plasmid in Vibrio anguillarum: essential role in siderophore biosynthesis.

Products encoded in the trans-acting factor (TAF) region are necessary for the biosynthesis of anguibactin and for maximal expression of iron transport and biosynthesis genes in the plasmid-encoded iron-scavenging system of Vibrio anguillarum. Here we identify angB, a locus located in the TAF region, which encodes products essential for anguibactin biosynthesis. We demonstrate that a 287-amino-acid polypeptide, encoded by angB and designated AngB, has an isochorismate lyase activity necessary for the synthesis of 2, 3-dihydroxybenzoic acid, an anguibactin biosynthesis intermediate. Complementation of various angB mutations provided evidence that an additional, overlapping gene exists at this locus. This second gene, designated angG, also has an essential biosynthetic function. The angG gene directs the expression of three polypeptides when overexpressed in Escherichia coli, all of which are translated in the same frame as AngB. The results of site-directed mutagenesis and in vivo phosphorylation experiments suggest that the carboxy-terminal end of AngB and the AngG polypeptide(s) function as aryl carrier proteins involved in the assembly of the anguibactin molecule. Our results also show that the regulatory functions of the TAF are encoded in a region, TAFr, which is distinct from and independent of the angB and angG genes.

Optimization of CT colonography technique: prospective trial in 180 patients.

PURPOSE: To assess the added benefits of prone positioning in addition to supine positioning and oral iodinated contrast medium for help in the detection of colonic polyps at computed tomographic (CT) colonography. MATERIALS AND METHODS: CT colonography was performed in prone and supine positions in 180 patients with polyps or risk factors for colonic neoplasia. Patients were randomly assigned to receive a standard bowel preparation or a standard preparation plus oral iodinated contrast medium. One radiologist interpreted supine images alone, and another analyzed supine and prone images. All patients subsequently underwent colonoscopy. RESULTS: At colonoscopy, 121 large (> or =1-cm-diameter) polyps and 142 smaller (0.5-0.9-cm) polyps were identified. Prone positioning resulted in increased sensitivity for identification of patients with large (> or =1-cm) polyps (increase from 70% to 85%, P: =.004) and of patients with polyps 0.5 cm or larger (increase from 75% to 88%, P: <.005), with no change in specificity. Use of oral contrast medium did not significantly improve polyp detection even in the subset of patients in whom colonic fluid attenuation was markedly increased. CONCLUSION: Acquisition and review of supine and prone CT colonographic images significantly improves the ability to identify patients with polyps 0.5 cm in diameter or larger. Administration of oral iodinated contrast medium does not significantly improve polyp detection.

Renal cell carcinoma metastatic to the pancreas: clinical and radiological features.

OBJECTIVE: To review the clinical features, computed tomographic (CT) appearance, and treatment outcomes in a case series of patients with renal cell carcinoma (RCC) metastatic to the pancreas. PATIENTS AND METHODS: We retrospectively reviewed the records of 23 patients (15 men and 8 women) with RCC metastatic to the pancreas, detected by CT examination between 1986 and 1996. All patients had undergone a previous nephrectomy for RCC. RESULTS: Isolated mild elevation in liver function test results (in 5 patients) or in serum amylase level (in 8 patients) was observed. New-onset diabetes was detected in 3 patients. The CT characteristics of the pancreatic metastases generally resembled those of primary RCC with well-defined margins and greater enhancement than normal pancreas with a central area of low attenuation. The mean interval between resection of the primary RCC and detection of the pancreatic metastases was 116 months (range, 1-295 months). In 18 patients (78%), the pancreatic metastases were diagnosed more than 5 years after nephrectomy. The pancreas was the initial metastatic site in 12 patients (52%). Survival was shortened with higher tumor grade (mean survival time of 41 months and 10 months in patients with grade 2 and 3, respectively). Surgical resection was carried out in 11 patients (7 distal and 3 total pancreatectomies and 1 distal pancreatectomy followed 4 years later by total pancreatectomy), with 8 patients alive at a mean follow-up of 4 years, 6 of whom remained free of recurrence. Overall, 12 patients (52%) were alive at a mean of 42 months after diagnosis of metastatic disease. CONCLUSIONS: The appearance of metastatic RCC lesions in the pancreas closely resembles the appearance of primary RCC on CT images. Pancreatic metastases from RCC are frequently detected many years after nephrectomy. Patient survival correlates with tumor grade. Histologic analysis of pancreatic masses in patients with a history of resected primary RCC is important since the prognosis for RCC metastatic to the pancreas is much better than that for primary pancreatic adenocarcinoma.

Incidental extracolonic findings at CT colonography.

PURPOSE: To determine the frequency of extracolonic findings at computed tomographic (CT) colonography and the effect of these findings on subsequent patient treatment and cost. MATERIALS AND METHODS: Conventional transverse CT colonographic scans in 264 consecutive patients were evaluated independently by two radiologists. Extracolonic findings were classified as having high, moderate, or low clinical importance. The effect of CT findings on patient treatment was assessed with chart review. The cost of additional examinations was calculated by using 1999 Medicare reimbursements. RESULTS: Thirty (11%) patients had highly important extracolonic findings, which resulted in further examinations in 18 (7%) patients, including ultrasonography in 10, CT in 13, and intravenous pyelography in one. Six patients underwent surgery because of incidentally discovered CT colonographic findings. Two patients with findings of moderate or low importance underwent additional imaging. A total of $7,324 was required for work-up for extracolonic findings (mean of an additional $28 per examination). Three extracolonic malignancies were overlooked at CT colonography. CONCLUSION: Additional work-up of extracolonic CT colonographic findings was relatively infrequent but was often worthwhile when performed for lesions classified as highly important. The evaluation of extracolonic structures at CT colonography has definite limitations with regard to solid organs but can help detect serious disease without substantially increasing the cost per patient.

CT and MR imaging of primary cardiac malignancies.

Primary cardiac malignancies are rare tumors that are difficult to diagnose clinically. Different primary cardiac malignancies may have different clinical, morphologic, and radiologic features and intracardiac locations. Angiosarcoma is the most common primary cardiac malignancy. It tends to occur in the right atrium and involve the pericardium. Because of its tendency to hemorrhage, angiosarcoma often demonstrates areas of increased signal intensity with T1-weighted sequences. Undifferentiated sarcomas typically occur in the left atrium and have variable epidemiologic and radiologic features. Rhabdomyosarcoma is the most common primary cardiac malignancy in children and is more likely than other primary cardiac sarcomas to involve the valves. Primary cardiac osteogenic sarcoma almost always occurs in the left atrium and frequently demonstrates calcification. Certain features (eg, broad base of attachment, origin at a site other than the atrial septum) help differentiate this tumor from left atrial myxoma. Leiomyosarcoma favors the left atrium and tends to invade the pulmonary veins and mitral valve. Fibrosarcoma also tends to occur in the left atrium and is often necrotic. Liposarcoma is very rare and usually manifests as a large, infiltrating mass. Foci of macroscopic fat are occasionally seen. Primary cardiac lymphoma occurs more commonly in immunocompromised patients, frequently involves the pericardium, and, unlike other primary cardiac malignancies, may respond to chemotherapy. The advent of cross-sectional imaging has allowed earlier detection of primary cardiac malignancies as well as more accurate diagnosis and characterization.