Viral Haemorrhagic Septicemia Virus (VHSV) Isolated from Atlantic Herring, Clupea harengus, Causes Mortality in Bath Challenge on Juvenile Herring

Viral hemorrhagic septicaemia virus (VHSV) has been demonstrated to cause high mortalities in a wide range of teleosts, farmed as well as wild. In Europe, VHSV of genotypes Ib, Id, II, and III have been detected in wild fish, including Atlantic herring Clupea harengus, but disease outbreaks have not been observed in Atlantic herring and the effects on wild stocks are not well documented. Here, we have tested two VHSV isolates from herring (genotypes Ib and III, from the western coasts of Norway and Denmark, respectively) in a challenge experiment with herring (mean weight 2.59 g, SD 0.71 g) caught on the west coast of Denmark. The Norwegian genotype Ib isolate (NO-F-CH/2009) showed an accumulated mortality of 47% compared to 6% mortality with the Danish genotype III isolate 4p168 and zero in the unchallenged control group. In both groups, we found positive rt-RT-PCR and positive immunohistochemistry of VHSV from days 6 and 8 onward. With both isolates, the organs mainly affected were the heart and kidney. The results demonstrate the susceptibility of Atlantic herring to VHSV, and both genotypes gave pathological findings in several organs. Genotype III showed a low mortality rate, and the importance of this genotype for herring is therefore not determined. Genotype Ib showed both high prevalence and mortality, and this genotype is therefore likely to have a negative effect on wild Atlantic herring stocks. Further examinations to determine how VHSV can affect wild Atlantic herring stocks are needed.

P10.12.A CDK12/CDK13 inhibition disrupts a transcriptional program critical for glioblastoma survival

Background

Glioblastoma multiforme (GBM) is the most prevalent and aggressive malignant tumor of the central nervous system. With a median survival of only one year, GBM patients have a particularly poor prognosis, highlighting a clear need for novel therapeutic strategies to target this disease. Transcriptional cyclin-dependent kinases (CDK), which phosphorylate key residues of RNA polymerase II (RNAPII) C-terminal domain (CTD), play a major role in sustaining aberrant transcriptional programs that are key to development and maintenance of cancer cells.

Material and Methods

We used pharmacological inhibition and genetic ablation to study effects of CDK12/CDK13 depletion on the proliferatory and migratory capacity of GBM cells and mouse xenografts. SLAM-seq, CUT&RUN and cell cycle assays were used to study the mechanistic effects of CDK12/CDK13 depletion in GBM cells.

Results

CDK12/CDK13 depletion markedly reduced the proliferatory and migratory capacity of GBM cells, as well as in vivo growth. CDK12/CDK13 inhibition potentiated existing chemotherapeutic treatments. Mechanistically, inhibition of CDK12/CDK13 leads to a genome-wide abrogation of RNAPII CTD phosphorylation, which in turn disrupts transcription and cell cycle progression in GBM cells.

Conclusion

These results provide proof-of-concept for the potential of CDK12 and CDK13 as therapeutic targets for GBM.

Susceptibility and Pathology in Juvenile Atlantic Cod Gadus morhua to a Marine Viral Haemorrhagic Septicaemia Virus Isolated from Diseased Rainbow Trout Oncorhynchus mykiss

Simple Summary

VHSV (viral haemorrhagic septicaemia virus) is a globally important group of viruses, infecting a wide range of fish species, in both marine and freshwater. New initiatives are now being taken to re-establish Atlantic cod as an aquaculture species. Any susceptibility to diseases would be relevant for this industry. Atlantic cod was experimentally infected with a strain of VHSV originating from a disease outbreak of farmed rainbow trout in Norway. The fish infected by injection did develop the disease, as verified by investigations of tissue samples. However, no transmission of the virus to cohabitant fish (i.e., individuals sharing the tank with infected fish) was found. This indicates that, despite the fact that the virus is capable of causing disease in Atlantic cod, the degree and ability to infect the fish is limited.

Abstract

The first known outbreak caused by a viral haemorrhagic septicaemia virus (VHSV) strain of genotype III in rainbow trout occurred in 2007 at a marine farm in Storfjorden, Norway. The source of the virus is unknown, and cod and other marine fish around the farms are suspected as a possible reservoir. The main objective of this study was to test the susceptibility of juvenile Atlantic cod to the VHSV isolate from Storfjorden. As the pathology of VHS in cod is sparsely described, an additional aim of the study was to give a histopathological description of the disease. Two separate challenge experiments were carried out, using both intra peritoneal (ip) injection and cohabitation as challenge methods. Mortality in the ip injection experiment leveled at approximately 50% three weeks post challenge. Both immunohistochemical and rRT-PCR analysis of organs sampled from diseased and surviving fish confirmed VHSV infection. No VHSV was detected in the cohabitants. The results indicate that Atlantic cod has a low natural susceptibility to this VHSV genotype III strain. One of the most extensive pathological changes was degeneration of cardiac myocytes. Immunohistochemistry confirmed that the lesions were related to VHSV. In some fish, the hematopoietic tissue of spleen and kidney showed degeneration and immunostaining, classical signs of VHS, as described in rainbow trout. Positive immunostaining of the capillaries of the gills, suggests this organ as a useful alternative when screening for VHSV.

Health among immigrants in Norway, results from the Living Condition Survey among immigrants 2016

Introduction

To manage immigrants` health needs is an important challenge for the society. This report gives knowledge about the status of immigrant health in Norway, which can be used in planning of health services.

Methods

Statistics Norway carried out a Living Condition Survey among immigrants in 2016. We report the prevalence of health outcomes (self-reported health, cardiovascular diseases, hypertension, diabetes, back- and neck problems, impaired functioning, mental health problems, problems with sleeping, overweight) and lifestyle (alcohol, smoking, physical activity) by country of origin and assess associations between health and sociodemographic (age, education, income) and migration related (age at immigration, duration of residence, Norwegian proficiency) variables, as well as discrimination and employment. Immigrants from twelve countries were interviewed. The questionnaire was translated into the main languages in the twelve countries and English. In this report, 4399 participants aged 16-66 years were included.

Results

There were large variations in health according to country of origin and gender. Immigrants experienced a deterioration in health at younger age than non-immigrants did. The educational gradient in health was less pronounced among immigrants than among others. Perceived discrimination was related to mental health problems. Some immigrant groups had a high proportion of smokers. In most groups a considerable proportion was drinking alcohol and a low proportion were physically active.

Conclusions

Future research should take into account differences in health according to country of origin and gender. The importance of physical and social circumstances for immigrant health emphasizes the need for structural population-based initiatives to promote health.

Key messages

Immigrant health varies by country of origin and gender. Physical and social environment is important for immigrant health.

Pathology of experimentally induced mouthrot caused by Tenacibaculum maritimum in Atlantic salmon smolts

Mouthrot, caused by Tenacibaculum maritimum is a significant disease of farmed Atlantic salmon, Salmo salar on the West Coast of North America. Smolts recently transferred into saltwater are the most susceptible and affected fish die with little internal or external clinical signs other than the characteristic small (usually < 5 mm) yellow plaques that are present inside the mouth. The mechanism by which these smolts die is unknown. This study investigated the microscopic pathology (histology and scanning electron microscopy) of bath infected smolts with Western Canadian T. maritimum isolates TmarCan15-1, TmarCan16-1 and TmarCan16-5 and compared the findings to what is seen in a natural outbreak of mouthrot. A real-time RT-PCR assay based on the outer membrane protein A specific for T. maritimum was designed and used to investigate the tissue tropism of the bacteria. The results from this showed that T. maritimum is detectable internally by real-time RT-PCR. This combined with the fact that the bacteria can be isolated from the kidney suggests that T. maritimum becomes systemic. The pathology in the infected smolts is primarily mouth lesions, including damaged tissues surrounding the teeth; the disease is similar to periodontal disease in mammals. The pathological changes are focal, severe, and occur very rapidly with little associated inflammation. Skin lesions are more common in experimentally infected smolts than in natural outbreaks, but this could be an artefact of the challenge dose, handling and tank used during the experiments.

Guidelines for health and welfare monitoring of fish used in research

The aim of this paper is to provide background material necessary for the development of international guidelines for the health and welfare monitoring of fish used in research. It provides an overview of present guidelines and discusses why more detailed and species-specific guidelines are needed. A major issue within fish research is to document the situation today and point out areas where improvements are needed.

First Description of a New Disease in Rainbow Trout (Oncorhynchus mykiss (Walbaum)) Similar to Heart and Skeletal Muscle Inflammation (HSMI) and Detection of a Gene Sequence Related to Piscine Orthoreovirus (PRV)

In fall 2013, anorexia, lethargy and mortalities up to 10-12,000 dead fish per week were observed in rainbow trout Oncorhynchus mykiss in three fresh water hatcheries (salinity 0-1 ‰) on the west coast of Norway. The fish (25-100 g) showed signs of circulatory failure with haemorrhages, ascites and anaemia. The histopathological findings comprised inflammation of the heart and red muscle and liver necrosis. The affected fish had a common origin. Disease and mortalities were also observed up to four months after sea water transfer. Microbiological examination did not reveal presence of any known pathogens. Based on histopathological similarities to heart and skeletal inflammation (HSMI) in Atlantic salmon, associated with piscine orthoreovirus (PRV), extended investigations to detect a virus within the family Reoviridae were conducted. By the use of primer sets targeting the PRV genome, a sequence with 85% identity to a part of segment S1 of PRV was obtained. Further analysis showed that the virus sequence could only be aligned with PRV and no other reoviruses both on amino acid and nucleotide level. Two PCR assays were developed for specific detection of the virus. High amounts of the virus were detected in diseased fish at all affected farms and low amounts were detected in low prevalence at the broodfish farms. Further investigations are needed to determine if the virus is associated with the new disease in rainbow trout and to further characterize the virus with respect to classification, relationship with PRV, virulence, pathology and epidemiology.

Screening for viral hemorrhagic septicemia virus in marine fish along the Norwegian coastal line

Viral hemorrhagic septicemia virus (VHSV) infects a wide range of marine fish species. To study the occurrence of VHSV in wild marine fish populations in Norwegian coastal waters and fjord systems a total of 1927 fish from 39 different species were sampled through 5 research cruises conducted in 2009 to 2011. In total, VHSV was detected by rRT-PCR in twelve samples originating from Atlantic herring (Clupea harengus), haddock (Melanogrammus aeglefinus), whiting (Merlangius merlangus) and silvery pout (Gadiculus argenteus). All fish tested positive in gills while four herring and one silvery pout also tested positive in internal organs. Successful virus isolation in cell culture was only obtained from one pooled Atlantic herring sample which shows that today's PCR methodology have a much higher sensitivity than cell culture for detection of VHSV. Sequencing revealed that the positive samples belonged to VHSV genotype Ib and phylogenetic analysis shows that the isolate from Atlantic herring and silvery pout are closely related. All positive fish were sampled in the same area in the northern county of Finnmark. This is the first detection of VHSV in Atlantic herring this far north, and to our knowledge the first detection of VHSV in silvery pout. However, low prevalence of VHSV genotype Ib in Atlantic herring and other wild marine fish are well known in other parts of Europe. Earlier there have been a few reports of disease outbreaks in farmed rainbow trout with VHSV of genotype Ib, and our results show that there is a possibility of transfer of VHSV from wild to farmed fish along the Norwegian coast line. The impact of VHSV on wild fish is not well documented.

Vibrio salmonicida pathogenesis analyzed by experimental challenge of Atlantic salmon (Salmo salar)

Cold-water vibriosis (CV) is a bacterial septicemia of farmed salmonid fish and cod caused by the Gram-negative bacterium Vibrio (Aliivibrio) salmonicida. To study the pathogenesis of this marine pathogen, Atlantic salmon was experimentally infected by immersion challenge with wild type V. salmonicida and the bacterial distribution in different organs was investigated at different time points. V. salmonicida was identified in the blood as early as 2 h after challenge demonstrating a rapid establishment of bacteremia without an initial period of colonization of the host. Two days after immersion challenge, only a few V. salmonicida were identified in the intestines, but the amount increased with time. In prolonged CV cases, V. salmonicida was the dominating bacterium of the gut microbiota causing a release of the pathogen to the water. We hypothesize that V. salmonicida uses the blood volume for proliferation during the infection of the fish and the salmonid intestine as a reservoir that favors survival and transmission. In addition, a motility-deficient V. salmonicida strain led us to investigate the impact of motility in the CV pathogenesis by comparing the virulence properties of the mutant with the wild type LFI1238 strain in both i.p. and immersion challenge experiments. V. salmonicida was shown to be highly dependent on motility to gain access to the fish host. After invasion, motility was no longer required for virulence, but the absence of normal flagellation delayed the disease development.

Flavobacterium psychrophilum associated with septicaemia and necrotic myositis in Atlantic salmon Salmo salar: a case report

We describe the first case from Norway of increased mortality in Atlantic salmon Salmo salar (L.), with septicaemia and necrotic myositis, associated with infection by Flavobacterium psychrophilum. The outbreak occurred in smolt of 60 to 100 g in fresh water on a land-based farm in Western Norway during winter 2008-2009. The water temperature was < 5 degrees C and the accumulated mortality was 7.0%. Necropsy of dead and moribund fish revealed a swollen dark spleen, pale liver, serohaemorrhagic ascites and haemorrhage in the abdominal fat and muscle. F. psychrophilum was isolated from the kidney and spleen of diseased fish. Muscle biopsy revealed the presence of long filamentous rods in necrotic areas of skeletal muscle. Immunohistochemistry was positive for F. psychrophilum. Identification of cultured isolates as F. psychrophilum was confirmed using phenotypic testing and sequencing of the 16S rRNA gene. Analysis by allele-specific polymerase chain reaction (allele-specific PCR) indicated that 2 different genotypes of the bacterium were present in the outbreak.

Functional outcome in sarcomas treated with limb-salvage surgery or amputation

Purpose. In all patients treated at the Centre for Bone and Soft Tissue Sarcomas of Aarhus the functional outcome is prospectively evaluated by use of the Enneking system for the functional evaluation after surgical treatment of tumours of the musculoskeletal system. This system has been accepted by the Musculoskeletal Tumour Society and the International Symposium on Limb Salvage.

Patients/methods. In the present study the functional outcome after limb-salvage surgery (89 patients) and amputation (58 patients) was compared. In the limb-salvage group the treatment was surgery alone in 50% and surgery combined with either radiotherapy in 39% or chemotherapy in 11%. Inclusion criteria were: Deep seated extremity sarcomas, age >14 years, more than 1 year post-treatment follow-up time and alive at the end of the study. Median age was 49 years (range 14–88 years). Median tumour diameter was 8 cm (range 1–20 cm), median follow-up time was 4.8 years (range 1–11 years). Wilcoxon and ^χ2-tests were used for statistical analyses.

Results. The two groups were comparable according to age, sex, size of tumour, type of tumour, location of tumour, as well as post-treatment follow-up time. The functional scores were significantly higher after limb-salvage surgery as compared to amputation, the median scores being 85 and 47, respectively (p<0.001). A similar difference was observed if the Enneking scores were subdivided into general health-related scores and extremity-related scores. No association was found between functional scores and the following factors by use of univariate analysis: size of tumour, radiation therapy, localization of tumour and surgical margin.

Discussion. We conclude that this study indicates that limb-salvage surgery is associated with a better functional outcome than that observed after amputation. However, whether this also indicates a difference in quality of life needs further studies.

A review of the need and possible uses for genetically standardized Atlantic salmon (Salmo salar) in research

Large numbers of Atlantic salmon ( Salmo salar) are used as research animals in basic research and to solve challenges related to the fish-farming industry. Most of this research is performed on farmed animals provided by local breeders or national breeding companies. The genetic constitution of these animals is usually unknown and highly variable. As a result, large numbers of fish are often needed to produce significant results, and results from one study are often impossible to reproduce in another facility. The production of standardized salmon could in many cases reduce the number of animals used in research and at the same time provide more reproducible results. This paper provides an overview of the methods available for the production of standardized Atlantic salmon, and discusses the pros and cons of each technique. The use of zebrafish and other well-defined laboratory fish species as a model for salmon is also discussed. Access to genetically defined fish would greatly benefit the scientific community, in the same way as genetically defined lines of rodents have revolutionized mammalian research.

Quantitative investigation of antigen and immune response in nervous and lymphoid tissues of Atlantic halibut (Hippoglossus hippoglossus) challenged with nodavirus

The present study reports the quantitative analysis of the spatio-temporal development of nodavirus infection and corresponding immune response in juvenile Atlantic halibut (Hippoglossus hippoglossus) challenged by intramuscular injection of nodavirus. Novel quantitative real-time RT-PCR protocols were applied to evaluate the absolute copy numbers of nodavirus RNA2 (RNA2) and secretory-IgM mRNA (sec-igmicro) in the eye, brain, mid/posterior kidney and spleen sampled over a period of 81 days. In the eye and brain, levels of both RNA2 and sec-igmicro increased significantly early in the infection. In the spleen and mid/posterior kidney, both RNA2 and sec-igmicro were detected but the levels remained unchanged during the experimental period. The levels of RNA2 and sec-igmicro in the eye and brain were strongly correlated (P<0.0001). Nodavirus antigen was demonstrated by immunohistochemistry (IHC) in the retina of eyes from a relatively few fish from day 34 post challenge (brain not examined), but not at any time in the spleen and anterior kidney. By IHC, IgM+ cells were observed in conjunction with nodavirus positive IHC labelling in the retina. In both the spleen and anterior kidney, the number of IgM+ cells increased from day 3 post challenge. By conventional real-time RT-PCR, RNA2 was only sporadically demonstrated in the posterior intestine, heart and gills. ELISA analysis revealed a nodavirus specific antibody response in serum that was significant from day 18 post challenge. No clinical signs or mortality related to nodavirus infection were observed in the challenged halibut. The results suggest that the nodavirus infection induced a significant antibody response through activation of B-cells in the kidney and spleen, and involved a substantial migration of antibody-secreting cells to infected peripheral tissues.

Immune- and enzyme histochemical characterisation of leukocyte populations within lymphoid and mucosal tissues of Atlantic halibut (Hippoglossus hippoglossus)

Leukocyte populations within the kidney, spleen, posterior intestine and gills of Atlantic halibut were investigated using a panel of histological, enzyme- and immunohistochemical methods. In the kidney and spleen, a diverse population of leukocytes was associated with the extensive network of sinusoids and larger blood vessels present in these tissues. IgM+ cells (B-cells, plasma cells and IgM-bearing macrophages) and large mononuclear cells showing reactivity for non-specific esterase (NSE) and acid phosphatase (ACP), representing macrophage populations, were often associated with vessel walls that were also the site of trapping of fluorescent microspheres. In the kidney, trapping of 0.1 and 0.5 microm diameter microspheres occurred at these sites but in the spleen, the 0.1 microm diameter microspheres were retained in ellipsoids. The lymphoid tissues of the kidney and spleen possessed a spread population of 5'-nucleotidase+ (5'N+) cells but compartmentalisation of the splenic white pulp was suggested by an absence of these 5'N+ reticular cells in areas associated with melanomacrophage accumulations and in areas rich in IgM+ cells. A striking feature of the mucosal tissues was the diversity of leukocyte populations within the epithelium particularly of the posterior intestine, including IgM+ cells and NSE+, ACP+ and 5'N+ mononuclear cells. Although limited in numbers in the posterior intestine, IgM+ cells were more common in the epithelium than in the lamina propria. In the gills, leukocytes as detected by enzymatic reactivity were scarce, but IgM+ cells were very abundant in the stratified epithelium of the gill arch and filaments. The difference in distribution of these leukocyte populations between the intestines and gills suggested a compartmentalisation of the mucosal immune system and the need to assess the immunological competence of mucosal tissues in Atlantic halibut.

Characterization of nodavirus and viral encephalopathy and retinopathy in farmed turbot, Scophthalmus maximus (L.)

An outbreak of nodavirus infection in turbot larvae is described with respect to histopathology, immunohistochemistry, cell culture cultivation, RT-PCR amplification and sequence analysis of the capsid protein gene RNA2. Affected turbot developed classical signs of viral encephalopathy and retinopathy (VER) with abnormal swimming behaviour and high mortality levels. In the acute stage of infection, light microscopy revealed vacuolation of the central nervous system (CNS), with positive immunohistochemical staining for nodavirus. Later in the infection, CNS lesions appeared more chronic and contained clusters of cells immunopositive for nodavirus. Bacterial overgrowth in the intestines of the fish may have provoked or influenced the course of the nodavirus infection. We were unable to propagate the virus in cell culture. While RT-PCR using primers designed to detect Atlantic halibut nodavirus gave negative results, further testing with primers complementary to a more conserved region of RNA2 resulted in amplification of a product of the expected size. The entire RNA2 segment was cloned and sequenced. Sequence alignment showed that the turbot nodavirus (TNV) was different from previously described fish nodaviruses. In addition, phylogenetic analysis based on an 823 nt region of the sequence indicated that TNV clustered outside the four established fish nodavirus genotypes, suggesting a fifth genotype within the betanodaviruses.

A sequential study of pathological findings in Atlantic halibut, Hippoglossus hippoglossus (L), throughout one year after an acute outbreak of viral encephalopathy and retinopathy

Following a natural outbreak of viral encephalopathy and retinopathy (VER) at a commercial farm in Norway, surviving Atlantic halibut, Hippoglossus hippoglossus, were sequentially studied for distribution of nodavirus, immune response and histopathology over 1 year. Typical clinical signs and histopathology of VER were observed during the acute stage of the disease. Most of the surviving fish became subclinical carriers of nodavirus with clusters of nodavirus-containing cells in the central nervous system. Four random samplings of presumably healthy fish were performed from two fish groups, with low and high growth rates respectively, over a 7-month period. Immunohistochemical (IHC) examination revealed a higher number of nodavirus-positive cells in fish with a low growth rate than in fish with a high growth rate. All IHC positive fish were also reverse transcriptase polymerase chain reaction (RT-PCR) positive for nodavirus and for nodavirus antibodies detected by enzyme-linked immunosorbent assay (ELISA) at all sampling points. The percentage of PCR- and ELISA-positive fish remained high throughout the year, while the number of IHC-positive fish decreased, especially in the group with a high growth rate. Several other histopathological changes were observed, including pericarditis, steatitis, changes in liver and kidney, and necrosis of the intestinal wall. None of these findings seemed to be related to the nodavirus infection. Nodavirus was reisolated in cell culture from subclinically infected fish one year after the acute VER outbreak, which indicates that the virus was still infectious.

Acute and persistent experimental nodavirus infection in spotted wolffish Anarhichas minor

Spotted wolffish Anarhichas minor (approx. 0.7 g) were found to be susceptible to infection with a nodavirus isolated from Atlantic halibut (AHNV) by bath-challenge. During the acute stage of infection, 4 to 8 wk post-challenge, viral encephalopathy and retinopathy (VER) were diagnosed by histopathology, immunohistochemistry (IHC) and reverse transcriptase-polymerase chain reaction (RT-PCR). Accumulated mortality was 52% in the challenged group. The surviving fish were sampled 16 wk post-challenge, by which time they had grown to approximately 17 g. No clinical signs of VER were observed in these fish. RT-PCR examination revealed the presence of nodavirus in several organs of the survivors, but no immunopositive cells were detected by IHC. Nodavirus was reisolated from fish at the last sampling in SSN-1 cells, showing that nodavirus retains virulence in persistently infected wolffish for at least 16 wk post-bath-challenge.

Heart morphology in wild and farmed Atlantic salmon Salmo salar and rainbow trout Oncorhynchus mykiss

The normal shape of the salmonid ventricle is a triangular pyramid with the apex pointing caudoventrally. A strong positive correlation has been established between this shape and optimum cardiac output and function. Domesticated salmonids appear to have developed a more rounded ventricle with misaligned bulbus arteriosus. Several reports from fish health veterinarians indicate that fish with abnormal heart morphology have a high mortality rate during stress-inducing situations like grading, transportation and bath treatments. The present paper compares and describes the ventricle morphology of wild vs. farmed Atlantic salmon, and wild steelhead (anadromous rainbow trout) vs. farmed rainbow trout. Several parameters were measured to provide numerical measurement of the differences in shape, i.e. height:width ratio and the angle between the longitudinal ventricular axis and the axis of the bulbus arteriosus. We conclude that the hearts of farmed fish are rounder than those in corresponding wild fish, and that the angle between the ventricular axis and the axis of the bulbus arteriosus is more acute in wild fish than in their farmed counterparts. Further studies are necessary to reveal the prevalence, functional significance and possible causes of these abnormal hearts.

Experimental infection of Atlantic halibut Hippoglossus hippoglossus with nodavirus: tissue distribution and immune response

Atlantic halibut Hippoglossus hippoglossus, age 8 mo and weighing 20 g, were challenged by either intraperitoneal injection (i.p.) or by bath exposure using nodavirus isolated from Atlantic halibut. Fish were sampled at intervals over a 41 d period, starting on Day 5 post-challenge. Although no clinical disease or mortality was recorded, the data show that nodavirus did successfully propagate in i.p.-challenged fish. Using conventional end-point reverse transcription (RT)-PCR, nodavirus was detected in the kidney of all examined i.p.-challenged fish, and further in the head, heart, liver and posterior intestine of most of these individuals. Quantitative real-time RT-PCR revealed that the amount of virus in head samples from the i.p.-challenged group increased during the experiment. The presence of nodavirus in nervous tissue of i.p.-challenged fish was detected by immunohistochemistry from Day 13 post-challenge. In the retina, virus positive cells were found adjacent to the circumferential germinal zone at the ciliary margin towards the iris. In the brain, a few positive cells were detected in the tectum opticum. An ELISA was developed to detect anti-nodavirus activity in plasma. The method included an optimized coating procedure, which allowed the use of non-purified nodavirus as the coating antigen in a simple indirect ELISA. An anti-nodavirus antibody response was detected from Day 19 post-challenge in i.p.-challenged fish, while a response was not detected in the bath-challenged or control fish. This experiment demonstrates a subclinical nodavirus infection in Atlantic halibut at a post-juvenile stage induced by i.p. injection of virus.

Cardiac abnormality with associated hernia in farmed rainbow trout Oncorhynchus mykiss

A new type of cardiac malformation in rainbow trout Oncorhynchus mykiss from a broodstock fish farm is described. The ventricle of affected fish was located dorsodextrally to the atrium, while the latter was saccular, grossly enlarged and protruded through the muscles of the ventral body wall, forming a hernia covered only by dermis and epidermis. Histopathological changes included hypoplasia of the outer compact layer of the ventricular myocardium and severe distension of trabecular structures within the ventricle and atrium. Affected fish tolerated stress very poorly, and the majority of the affected fish died during the freshwater period. The causation(s) are not known, but hereditary and environmental factors are likely, as no infectious agents were isolated or detected microscopically.

Pericarditis and myocarditis in farmed Atlantic halibut Hippoglossus hippoglossus

Farming of Atlantic halibut Hippoglossus hippoglossus is a growing industry in Norway. This study comprises the first description of heart morphology in fish from one Atlantic halibut farm. Fish with no clinical signs of disease were randomly sampled (8 to 12 mo old, weight 1 to 50 g). The hearts were studied by light and electron microscopy and samples were taken from the kidney and pericardial cavity for bacteriological examination. Slight to severe changes were found in most hearts at all samplings. The most serious pericardial and myocardial changes were seen in larger fish (15 to 50 g). In some of the hearts the affected pericardium formed multifocal protrusions. Eight fish had an adhesion between the apex of the ventricle and the parietal wall of the pericardial cavity. Results of bacteriology and immunohistochemistry investigations for common disease agents were negative.

Training nurses to support carers of relatives with schizophrenia

Carers have an enormous amount of responsibility for the welfare and management of people with a mental illness in Britain, and many require help if they are to continue caring. Mental health nurses may be in a key position to offer support, but they are often unclear of what is required and how it should be delivered. Existing UK nurse-led psychosocial interventions for families often focus on the needs of the patient rather than the carer. This article describes a needs-led support service that has been designed for carers whose relatives are diagnosed with schizophrenia. It recognizes the importance of a collaborative partnership between carers and nurses. In 2000, 10 mental health nurses were trained to deliver this support to carers. An evaluation is currently underway. This article outlines the principles of the training programme and how it might enable nurses to meet the carers' needs.

[Nerve biopsy]

Nerve biopsy, if undertaken at centres with appropriate expertise, may be a valuable diagnostic procedure in selected patients with peripheral neuropathy. Sural nerve biopsy and skin biopsy for evaluation of epidermal nerves are described. Indications, surgical procedure, preparation and transport are reviewed. Usually the patient has to be admitted to a hospital with the necessary resources for a comprehensive battery of nerve tissue processing, including teasing and electron microscopical examination, and other investigative procedures. Another option, when practically and economically feasible, is to obtain sural nerve biopsy from several (2-4) patients performed by a skilled surgeon at the local (central) hospital. A technician from a neuromuscular centre or laboratory of neuropathology should be at the site to provide immediate and proper preparation and transport of the tissue samples. An example of peripheral nerve vasculitis with teased nerve fibers in early and late axonal degeneration is presented as an illustration. Sural nerve biopsy is useful in selected cases, particularly in order to demonstrate peripheral nerve vasculitis. For detection of small fiber neuropathy in the investigation of painful neuropathies, skin biopsy for evaluation of epidermal nerves may be an appropriate alternative.

Responsiveness of leg alignment changes associated with articular pressure testing to spinal manipulation: the use of a randomized clinical trial design to evaluate a diagnostic test with a dichotomous outcome

OBJECTIVE

A study was undertaken to assess the stability of leg alignment reaction to a pressure challenge and its responsiveness to an adjustive intervention.

DESIGN

Prospective, double-blind clinical trial of a diagnostic test.

SETTING

Laboratory: Center for Technique Research.

PARTICIPANTS

Forty-two chiropractic college students, faculty and staff.

INTERVENTIONS

A high-velocity, low-amplitude, short lever adjustment of a single vertebra from among C1 and T3-T7; or a sham adjustment similar to a manual diagnostic pressure test at C1, T3-T7 or T9-T10.

MAIN OUTCOME MEASURES

Leg alignment reactivity: An increase in leg alignment discrepancy (yes or no) following a metered pressure challenge to a vertebra.

RESULTS

On average, stability was poor at T3-T7 (Kappa = 0.04), moderate at C1 (K = 0.47), and fair for sham pressure tests (K = 0.30). Responsiveness: The proportion of positive baseline leg alignment reactions that responded (became negative) to sham adjustment was 95% at T3-T7 and 55% at C1. Further analysis was untenable since too few vertebrae were implicated for an adjustment.

CONCLUSIONS

For the population investigated, the majority of the responsiveness of the leg alignment diagnostic test to a rotatory adjustment appears to be a diagnostic illusion (i.e., background noise unrelated to a treatment intervention). Further research with different subject populations, regions of investigation, leg alignment measurement techniques and vertebral challenge techniques are indicated.

Reactivity of leg alignment to articular pressure testing: evaluation of a diagnostic test using a randomized crossover clinical trial approach

OBJECTIVE

A study was undertaken to assess the reliability of detecting leg alignment changes (reactivity) and to determine if the observed leg alignment reactivity can be attributed to a rotatory articular pressure challenge.

DESIGN

Prospective double-blind crossover trial of a diagnostic test.

SETTING

Laboratory: Center for Technique Research.

PARTICIPANTS

Forty-two chiropractic college students, faculty and staff.

INTERVENTIONS

A standardized force of 2 or 3 kg was applied with a 1 cm2 rubber-tipped pressure algometer on the lateral aspect of the T3-T7 spinous processes and the posterior aspect of the lateral masses of C1.

MAIN OUTCOME MEASURES

Leg alignment reactivity: an increase in leg alignment discrepancy (yes or no) following a diagnostic intervention.

RESULTS

The reliability for detecting leg alignment reactivity was poor: on average, Kappa = 0.05 in the thoracics and 0.06 at C1. On average, the attributable risk of leg alignment reactivity (pressure test risk--sham test risk) was less than 4%. In many cases, the sham rate was greater than the pressure test rate.

CONCLUSIONS

For the population investigated, leg alignment reactivity to rotatory pressure testing can, in the majority of cases, be attributable to background noise. This procedure was not found to be viable for identifying vertebrae for adjustment. Further research with different subject populations, regions of investigation, leg alignment measurement techniques and vertebral challenge techniques are indicated.

Artefacts and morphological changes during chemical fixation

The normally 'condensed' (darkly stained) chromosomes of dinoflagellates decondense by swelling. This occurs in an increasing number of cells when the concentration of added OsO4 is decreased. With different fixatives other types of disintegration can be observed, which vary with the concentration. With cryofixation and freeze-substitution the chromosomes are most 'condensed'. Escherichia coli infected with bacteriophage T4, with or without active lysozyme production, were studied by optical densitometry for partial lysis and by light and electron microscopy for observing swelling. When active lysozyme is present some of the acrolein (2.5%)-glutaraldehyde (2%)-fixed cells swell at 0 degrees C, but do not in the absence of lysozyme nor when fixed at room temperature. If OsO4 is added at concentrations < or = 0.5%, partial lysis occurs when lysozyme is present. The optical density decreases, the cells lose some matter and swell slightly. The corresponding electron micrographs show gap formation by curdling and/or a decreased concentration of the cytoplasm which reveals certain phage-related particles.

Coralline shape of the bacterial nucleoid after cryofixation

A new procedure of immunostaining sections of cryofixed and freeze-substituted Escherichia coli shows that DNA extends from its bulk into small ribosome-free spaces throughout the cytoplasm, resulting in a coralline-shaped nucleoid. Low-resolution imaging of a bacterium reconstructed from serial sections demonstrated that the small excrescencies are not resolved. The resulting photograph shows the same features as phase-contrast light micrographs.

Effect of cooling on the intracellular concentrations of Na+, K+ and Cl- in cultured human endothelial cells

Cooling is accepted as a practical way of lowering cell metabolism in vein grafts during coronary by-pass surgery. We have previously shown that low temperature causes endothelial cells to become detached, both in in vitro and in vein graft. In this study we have looked at the effect of cold on the concentrations of intra- and extracellular electrolytes. Human endothelial cells were grown on titanium grids for electron microscopy. The cells were incubated for 30 min at 37 degrees, 20 degrees, and 4 degrees C with cell culture medium containing human serum, and at 20 degrees and 4 degrees C with heparinized sodium acetate solution with serum, frequently used for flushing and distending vein grafts. Freeze-dried cells were then subjected to elemental X-ray microanalysis. The ambient fluid was analysed by flame photometry. At 20 degrees and 4 degrees C, intracellular concentration of sodium increased, and potassium decreased, compared with controls (37 degrees C). The changes in sodium concentrations were aggravated when cell culture medium was replaced by heparinized sodium acetate. The intracellular chloride concentration did not change when cells were stored in cold cell culture medium. The extracellular concentration of potassium increased with increasing incubation time at 4 degrees C. The connection between these findings and cell detachment is discussed.

What to expect from teleconferencing

Like other marvels of the electronic age, teleconferencing has been both oversold and underused. Though it has many potential uses, what managers know, or think they know, about it is generally based on misconceptions. Rather than relying only on vendors of teleconferencing, potential purchasers should first decide what their communication needs are, then choose the system that suits them best. These authors explain the new teleconferencing options and give guidelines for adapting them to a particular company.

A family systems approach to home dialysis

Dramatic increases in the cost of the end stage renal disease program are producing an emphasis on home dialysis with the patient and his family carrying the responsibility for this treatment. This requires an adjustment of the family's emotional system and role assignment to sustain members through the continued stress of chronic catastrophic illness. We are suggesting a model of intervention in which family members are encouraged to recognize stress caused by one member's illness and to make necessary changes in the family functioning.