bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparing Exemplar- and Rule-Based Theories of Categorization
Authors: Rouder Jeffrey N. , Ratcliff Roger
Published: April 2006

We address whether human categorization behavior is based on abstracted rules or stored exemplars. Although predictions of both theories often mimic each other in many designs, they can be differentiated. Experimental data reviewed does not support either theory exclusively. We find participants use rules when the stimuli are confusable and exemplars when they are distinct. By drawing on the distinction between simple stimuli (such as lines of various lengths) and complex ones (such as words and objects), we offer a dynamic view of category learning. Initially, categorization is based on rules. During learning, suitable features for discriminating stimuli may be gradually learned. Then, stimuli can be stored as exemplars and used to categorize novel stimuli without recourse to rules.
Beyond What Develops When
Authors: Amso Dima , Casey B.J.
Published: April 2006

There is no single methodology that can fully explain the nature of human development and learning. Yet, headway is being made on how cognitive milestones are achieved during development with the use of magnetic resonance imaging (MRI) technology. With this methodology, it is possible to assess changes in brain structure, function, and connectivity. Recent findings suggest that both progressive and regressive processes—as opposed to simple linear patterns of change—underlie changes in cognitive abilities. Functional MRI studies suggest that both biological maturation and learning correspond to a fine-tuning of neural systems with enhanced recruitment of task-relevant regions. This fine-tuning of cortical systems corresponds with their enhanced connectivity with cortical and subcortical circuitry. In sum, imaging has helped to move the field of cognitive development beyond questions of what develops and when, to how these changes may occur.
Who's Gay? Does It Matter?
Authors: Savin-Williams Ritch C.
Published: April 2006

To answer the question “Who's gay?”—and its logical follow-up, “Does it matter?”—researchers usually define homosexuality with reference to one of three components or expressions of sexual orientation: sexual/romantic attraction or arousal, sexual behavior, and sexual identity. Yet, the three components are imperfectly correlated and inconsistently predictive of each other, resulting in dissimilar conclusions regarding the number and nature of homosexual populations. Depending on which component is assessed, the prevalence rate of homosexuality in the general population ranges from 1 to 21%. When investigators define the homosexual population based on same-sex behavior or identity, they enhance the possibility of finding a biological basis for homosexuality and a compromised mental health (suicidality).
Gastro‐oesophageal reflux disease in ‘difficult‐to‐control’ asthma: prevalence and response to treatment with acid suppressive therapy
Authors: WONG C. H. , CHUA C. J. , LIAM C. K. , GOH K. L.
Published: April 2006

Background

The causal association between gastro‐oesophageal reflux disease (GERD) and difficult‐to‐control asthma is unclear.

Aim

To determine the prevalence of GERD and response to proton pump inhibitor therapy in patients with difficult‐to‐control asthma.

Methods

Consecutive patients with difficult‐to‐control asthma as defined by persistent and recurrent symptoms despite on optimal asthmatic medications were recruited for the study. GERD was diagnosed by symptoms, gastroscopy and 24‐h oesophageal pH monitoring. All patients were prescribed a course of lansoprazole 30 mg daily for 8 weeks. Improvement to treatment was assessed by a change in pulmonary symptom score and also by patient's subjective assessment of improvement.

Results

Seventeen of 30 (56.7%) patients with difficult‐to‐control asthma were diagnosed with GERD. Pulmonary symptom score improved significantly only in patients with GERD (35.0 to 21.0; P = 0.002). Twelve of 16 (75%) patients with GERD reported an improvement in asthma symptoms; 1 of 11 (9.1%) without GERD reported mild symptom improvement. There was no significant change in peak expiratory flow rate and forced expiratory volume.

Conclusions

More than half of patients with difficult‐to‐control asthma were diagnosed with GERD. In these patients the severity of asthma improved significantly with potent acid suppression therapy. This underlines the critical role of acid reflux in this subset of patients with difficult‐to‐control asthma.
On differences in skin tumours of Pacific and Atlantic Flatfish
Authors: PETERS NICOLAUS , PETERS GABRIELE , STICH HANS F. , ACTON ALF B. , BRESCHING GISELA
Published: April 2006

Abstract. Pacific flatfish from North American and Japanese coastal waters regularly manifest skin tumours. Those are generally papillomas, which develop from primary inflammatory nodules (vascularized nodules) on fish of a few months's age. Inside the epidermal part of the tumour slightly dedifferentiated malpighian cells change to rounded enlarged cells showing evidence of considerable degeneration (vacuolization and destruction of the cell organelles). These ‘X‐cells’, which compose the major part of the mature tumour, always remain characteristically separated from the surface, from the basal lamina, and from each other, by non‐enlarged ‘enyelope cells’.

Oval, similarly degenerate cells also occur in the tumour stroma, especially in the nodule‐like pre‐papillomatous stages and here they originate apparently from fibroblasts.

In the Atlantic, on the other hand, skin papillomas and other neoplastic skin growths occur relatively infrequently. The skin papillomas of Atlantic flatfish are considerably less complex. They belong to the relatively simple type which predominates in fishes in general–hyperplastic epidermal papillae which are supported and natured by branched folds of the dermal tissue (stroma).

Considering the close relationship between the Pacific and Atlantic flatfishes, the distinctive structure of the skin tumours of Pacific fish is considered to be due probably to the influence of a specific virus.
Host‐specific pathogenicity of strains of Vibrio anguillarum isolated from rainbow trout Salmo gairdneri Richardson and saithe Pollachius virens (L.)
Authors: Egidius E. C. , Andersen K.
Published: April 2006

Abstract. Vibrio anguillarum strains isolated from diseased rainbow trout were found to be pathogenic to salmonids and probably to a very low extent to saithe. Strains isolated from saithe were pathogenic to saithe and non‐pathogenic to salmonids.
Tissue reaction of the three‐spined stickleback Gasterosteus aculeatus L. to infection with Glugea anomala (Moniez, 1887)
Authors: DYKOVÁ IVA , LOM JIŘÍ
Published: April 2006

Abstract. Studies on an experimental infection of the stickleback (Gasterosteus aculeatus L.) with the microsporidian Glugea anomala conducted until day 126 post infection confirmed that xenoparasitic formations typical of the intracellular development of this microsporidian were responsible for a marked tissue reaction in the host. After a single oral infection, xenoparasitic formations developed in the subepithelial connective tissue of the glandular part of the stomach. The course of xenoma development was asynchronous. Up to the ‘cyst’ stage (xenomas filled with mature spores), their growth and development caused a pressure atrophy in the surrounding tissue. Later, the response to the presence of the xenoparasitic formation was the development of a granulomatous inflammatory reaction. Locally, the host responded to the infection by phagocytosis of mature spores by locally derived macrophages. In massive infections, changes occurred in the subepithelial connective tissue of the glandular part of the stomach (often the complete disappearance of tubular glands), which may result in a permanent influence on the function of this organ.
Ultrastructural study of epitheliocystis organisms from gill epithelium of the fish Sparus aurata (L.) and Liza ramada (Risso) and their relation to the host cell
Authors: PAPERNA I. , SABNAI I. , CASTEL M.
Published: April 2006

Abstract. Ultrastructural study of epitheliocystis organisms from gills of Sparus aurata (L.) and Liza ramada (Risso) revealed in each fish a new form of the organism which differed from epitheliocystis organisms previously described. In their size range, the presence of a plasma membrane, a trilaminated cell wall and a central nucleoid, these organisms resembled chlamydial organisms (PLT). However they differed from them in the following respects: in both species several morphological forms were recognized; hyphae or mycelium‐like forms and individual units, not comparable to any of the successive units described for Chlamydia organisms. Both organisms were contained within an inclusion in the host cell, but in epitlieliocysts from S. aM7‐ata apparently intracytoplasmic forms were also observed. Ultrastructural studies of the cytoplasmic wall of the epitheliocystis inclusion in S. aurata suggest that the epitheliocystis cyst remains contained in a single unruptured hypertrophied cell, while in i. ramada the final cyst is formed through the coalescence of several epithelial cells.
Fine structure of the peritrichous ectocommensal Zoothamnium sp. with emphasis on its mode of attachment to penaeid shrimp
Authors: FOSTER C. A. , SARPHIEF T. G. , HAWKINSF W. E.
Published: April 2006

Abstract. The colonial peritrich Zoottiamnium sp. is a common ectocommensal of shrimp. Heavy branchial infestations of this protozoan can cause mass mortalities of commercially important penaeid species in shrimp culture. In an effort to better understand the morphology of these organisms, the ciliates and their attachment to gills and pereiopods of Penaeus aztecus and P. setiferus were examined by transmission and scanning electron microscopy. Each zooid contains peristomial rows of cilia, numerous food vacuoles, a large macronucleus, one or more contractile vacuoles, freeribosomes, abundant mitochondria, and rough endoplasmic reticulum. The contractile spasmonehie is surrounded by striated tubules that appear to develop from scopular cilia. The pellicular surface is crenated and has numerous pores. The base of the ciliate's stalk forms a circular disc that fuses with the epicuticle but does not penetrate the underlying cuticle or epithelium. Intertwining microfibrils and osmiophilic particles in the stalk accumulate along the base and merge with the cuticular surface coat. This mode of attachment inflicts no damage to the host tissue and elicits no appreciable pathological response. The shrimp apparently suffocate when dense colonies reduce the respiratory surface area.
A new myxosporidan, Dicauda atherinodi n.g., n. sp. of the minnow, Notropis atherinoides Rafinesque
Authors: HOFFMAN G. L. , WALKER R.
Published: April 2006

Abstract. Dicauda atherinoidi n.g., n. sp. (Protozoa: Myxosporida) was found in feral minnows, Notropis atherinoides (Cyprinidae), from western Lake Erie (Sterling State Park), Michigan, and the lower Mohawk and Hudson Rivers, New York. Dicauda, closely related to Myxobolus, differs from it in having two, occasionally three or more, rigid tail‐like possibly mucoid appendages attached to the sutural ridge. The cysts are subdermal and most abundant on the head. Histological damage is not striking.
Exophiala salmonis infection in Atlantic salmon Salmo salar L.
Authors: RICHARDS R. H. , HOLLIMAN A. , HELGASON S.
Published: April 2006

Abstract. Infection of Atlantic salmon, Salmo salar L., in seawater with Exophiala salmonis is described. Histological effects consisted principally of granuloma formation, especially in the posterior kidney and spread appeared to occur both by extension and by the liaematogenous route. The nature of the outbreak suggested that the original infection occurred via contaminated food.

A comparison is made between this condition and systemic mycoses in other species.
Electron microscopy of an ulcerative dermal necrosis (UDN)‐like salmon disease in Finland
Authors: LOUNATMAA K. , JANATUINEN J.
Published: April 2006

Abstract. An ulcerative dermal necrosis‐like salmon disease appeared in Laukaa Central Fish Culture Station in Middle‐Finland in autumn 1976 showing lesions in different sites on diseased landlocked salmon Salmo salar L., sea trout Salmo trutta trutta L. and brown trout Salmo trutta lacustris L. Lesions from the diseased landlocked salmon were studied by transmission and scanning electron microscopy.

Both aquatic bacteria and fungi grew in abundance in the lesions, changing the fine structure of the epidermis.

In all of the lesions studied virus‐like particles 30–33 nm in diameter were found. The relationship of these particles to the disease is still unresolved.
Humoral antibody production by New Zealand eels, against the intestinal trematode Telogaster opisthorchis Macfarlane, 1945
Authors: McARTHUR C. P.
Published: April 2006

Abstract. It was shown by agar‐gel diffusion and passive haemagglutination that serum from the New Zealand eel Anguilla australis schmidtii Phillips and gut mucus from Anguilla dieffenbachii Gray contained precipitating antibody against antigen prepared from the intestinal trematode Telogaster opisthorchis MacFarlane, 1945. The estimated molecular weight determined by gel‐filtration on Sephadex G‐200 was 670,000 daltons. The 2‐mercaptoethanol sensitivity of this antibody suggested it was a macroglobulin analagous to γ M.

Eel sera also contained naturally occurring agglutinins and lysins against sheep RBC's. Agglutinins had an approximate molecular weight of 142,000, were sensitive to 2‐mercaptoethanol and occurred more frequently among larger eels. It was suggested that the appearance of agglutinins was an immunological phenomenon and that these antibodies were directed against the ABO system.
The pathology and histopathology of nephrocalcinosis in rainbow trout Salmo gairdneri Richardson in fresh water
Authors: HARRISON J. G. , RICHARDS R. H.
Published: April 2006

Abstract. A detailed histopathological study of naturally occurring and experimentally induced outbreaks of nephrocalcinosis was carried out on rainbow trout from a number of farms.

Histopathological effects were confined to the kidney, stomach and skeletal muscle. Lesions of the stomach wall were often found in the absence of renal lesions but muscle lesions were only found in the presence of severe renal damage. It was considered that the calcification was the result of deposition of calcium salts within necrotic tissue, and thus was dystrophic rather than metastatic. Variation between farms was considered to be due to variations in the effects of different aetiological factors in the complex series of physico‐chemical events which appear to induce the condition.
The influence of salinity on growth and structure of epidermal papillomas of the European eel Anguilla anguilla L.
Authors: PETERS GABRIELE , PETERS NICOLAUS
Published: April 2006

Abstract. Papillomatosis of the European eel Anguilla anguilla L. occurs predominantly in waters of low to medium salinity (3–20%). Tumour‐bearing eels were kept under laboratory conditions for several weeks in salt concentrations of 8, 15 and 30%. As opposed to those kept in freshwater, the experimental animals showed significant decreases in tumour growth rate. At the same time the tumour tissue underwent a marked redifferentiation, i.e. the originally poorly differentiated neoplastic tissue developed numerous mucous and club cells. The characteristic intercellular spaces of tumorous tissue disappeared with the formation of regular membrane interdigitations between adjacent cells. The nucleus to cytoplasm ratios of the neoplastic cells decreased to one‐third of those of the untreated tumour. These changes resulted in a reversion of the neoplastic tissue to a structural condition essentially similar to that of normal epidermis. After a period of 2 to 3 months an adaptation to the altered salinity of the external medium was evident in that the tumorous tissue began to return to its original state.
The occurrence of Henneguya psorospermica Thelohan, 1895 (Myxosporida) on perch, Perca fluviatilis L., from Llyn Tegid, Wales
Authors: ANDREWS C.
Published: April 2006

Abstract. The occurrence of cysts of Henneguya psomspermica on a population of perch was studied over a periot of 19 months. Cysts were restricted to the gill filaments although no attempt was made to assess the occurrence of earlier developnental stages of the parasite. Cysts were not recorded from a small sample of perch fry (aged 4–6 weeks). There was a peak of prevalence, and intensity of the infection in juvenile perch (aged 8–9 months), while the prevalence and intensity in adult perch (aged 1–1 and over) was low. In adult perch there was a seasonal November‐February.
Mass mortalities in silver carp Hypophthalmichthys molitrix (Valenciennes) associated with bacterial infection following handling
Authors: BEJERANO Y. , SARIG S. , HORNE M. T. , ROBERTS R. J.
Published: April 2006

Abstract. Mass mortalities in silver carp were related to infection of handling lesions with Proteus rettgeri, a gram negative bacterium normally found in the gut of poultry. Poultry faeces are used extensively to fertilize carp ponds and experimental infections showed that the condition could be reproduced by scarification and exposure to the micro‐organism or by its inoculation.
Pansteatitis in rainbow trout Salmo gairdneri Richardson: a clinical and histopathological study
Authors: ROBERTS R. J. , RICHARDS R. H. , BULLOCK A.M.
Published: April 2006

Abstract. Pansteatitis is a nutritionally mediated condition associated with the feeding of certain types of fish oil or unsaturated fatty acids of fish origin in a diet poor in vitamin E. It occurs regularly in mink, cats, pigs and poultry, all of which are fed on high fish diets, but this is the first description of the condition from cultured fish. The main presenting signs in affected rainbow trout were swimming aberrations, discolouration and high mortality after minimal stress. Gross postmortem features were restricted to changes in the liver and swimbladder but, at the microscopic level, histopathological changes involving inflammatory cellular infiltration of lipid tissue in swimbladder, abdominal and peripancreatic fat and hypodermis, accompanied by myopathic changes, were regularly observed.
Studies on cryptocaryoniasis in marine fish: effect of temperature and salinity on the reproductive cycle of Cryptocaryon irritans Brown, 1951
Authors: CHEUNG P. J. , NIGRELLI R. F. , RUGGIERI G. D.
Published: April 2006

Abstract. Trophonts of Cryptocaryon irritans Brown from infected three‐spot damselfish, Dascyllus trimaculatus Ruppell, were kept at temperatures ranging from 7 to 37°C to observe encystment and development of the tomites. At 30, 25 and 20°C, the percentage of trophonts that had encysted in 16 h were 70, 77 and 64% respectively; at 37°C, 44% encysted and at 7°C only 10% had encysted.

The optimum temperature for excystment was 30°C; 50% excysted in 5 days and 100% in 7 days. At 25°C, 60% of the tomites started to excyst on the eighth day, and 70% on the ninth day. At 20°C, 10% started to excyst on the ninth day, reaching 40% on the tenth day. No excystment occurred at 37 and 7°C.

Newly encysted tomonts were placed in various dilutions of sea water (31 %0) and kept at temperatures ranging from 7 to 37°C. Low salinities, i.e. 16%0 and lower caused tomonts to rupture. At 37, 20 and 7°C, 35% of the tomonts started to rupture immediately in 50% sea water, while at 30 and 25 C, 30% of the tomonts ruptured in 25% seawater. However, none of the cysts developed normally at these dilutions. The percentage rupturing increased with decreasing salinity.
Neoechinorhynchus rutili (Müller, 1780) (Acanthocephala) in the whitefish Coregonm nasus (Pallas) sensu Svärdson from the Bay of Bothnia
Authors: VALTONEN E. TELLERVO
Published: April 2006

Abstract. The occurrence of Neoechinorhynchus rutili (Müller, 1780) in the white‐fish Coregonus nasus (Pallas) sensu Svardson from the Bay of Bothnia was investigated in 772 fish obtained as monthly or bimonthly samples during the period July 1975‐January 1977.

In both years most parasites were found only in November and December. All of the 402 parasites found were immature and very small. Most of them were in the first third of the intestine, and only a few were attached to the mucosa. No encysted parasites were found in other any tissues. It is thus suggested that the whitefish of the Bay of Bothnia is only an accidental host for N. rutili.

A clear correlation was found between the importance of ostracods in the diet and the occurrence of N. rutili. The first intermediate host in the Bay of Bothnia was shown to be an ostracod, Candona neglecta (Sars.).
Morbid behaviour of the commercial sand crab, Portunus pelagicus (L.), parasitized by Sacculina granifera Boschma, 1973 (Cirripedia: Rhizocephala)
Authors: BISHOP R. K. , CANNON L. R. G.
Published: April 2006

Abstract. The behaviour of crabs Portunus pelagicus infected with the rhizocephalan barnacle Sacculina granifera is examined and compared with that of normal uninfected crabs. With regard to alarm reactions, feeding and locomotion, the infected crabs behave as normal crabs. Their stance, defaecation and burying behaviour differ in that they must accommodate to the physical presence of a large body, the parasite, suspended between cephalothorax and abdomen. General body care is increased as a result of the increased epizoic fauna on the exoskeleton which develops when moulting ceases. Infected crabs with an externa resemble ovigerous females in terms of their moderate daylight activity and particularly the grooming care and attention given to the sac—a surrogate egg mass. Parasitized crabs excavate a depression and using the third walking legs (and often second and first as well) attend the externa as an ovigerous female attends her egg mass. The grooming of the externa is of equal periodicity to egg mass grooming behaviour, but is less prolonged at maximum intensity. Sac grooming behaviour begins 18 days after emergence of an externa and declines progressively if the externa is removed and the interna degenerates. In interactions with other crabs parasitized individuals initiate fewer and dominate fewer encounters than normal crabs of similar size and sex; and parasitized males, at least, are less active when with other crabs than when alone. It is concluded the parasite secretes a hormonal mimic which induces ovigerous behaviour which maximizes the survival of the parasite population.
An Exophiala‐like fungus as the cause of a systemic mycosis of marine fish
Authors: BLAZER V. S. , WOLKE R. E.
Published: April 2006

Abstract. A systemic Exophiala‐like mycosis occurred naturally in five genera of captive fishes and it was experimentally produced in three additional genera: Tautogolabrus adspersus (Walbaum), Pseudopleuronectes americanus (Walbaum) and Fundulus heteroclitus (L.) by intraperitoneal injection of spores. Histo‐pathologically both acute, necrotic and focal granulomatous reactions were present in naturally infected animals. The lesions were reproduced following spore inoculations while a diffuse, proliferative, granulomatous reaction followed inoculation of hyphae alone. Reports of systemic mycoses in fish and other animals due to pigmented or dematiaceous fungi are discussed and lesions compared.
Epidemiological aspects of proliferative kidney disease amongst rainbow trout Salmo gairdneri Richardson in Northern Ireland
Authors: FERGUSON H. W. , BALL H. J.
Published: April 2006

Abstract. The epidemiology of PKD is described as it relates to one affected farm in Northern Ireland. From 1972–1976 stocking and management practices led to mortality of 10–15% amongst the 0+fish. 1+or older fish were never affected. In 1977 and 1978, however, delaying the stocking of the farm until July eliminated deaths in the 0+fish, and mortality in these 1977‐moved fish the subsequent year remained at an absolute minimum. Preliminary observations suggest that a means of controlling the disease has been found.

Experimental work demonstrates that the resistance of 1 +or older fish is due to previous exposure and is not an age‐related immunity. Experimental work also suggests the presence of an incubation period of 6–7 weeks and that the peak time of infectivity is probably around May. None of the evidence detracts from the possibility that an infectious agent is involved although an attempt to transmit the disease failed.
Effects of Acholeplasma laidlawii and an unidentified mycoplasma on selected fish cell cultures and the replication of fish viruses
Authors: EMERSON M. , NICHOLSON B. L. , BAYER R.
Published: April 2006

Abstract. An unidentified mycoplasma was isolated from cultures of Atlantic salmon (AS) cells and implicated as the cause of cytopathic effects (CPE). The agent did not visibly affect RTG‐2 cells. Experimental infection of RTG‐2 cells with Acholeplasma laidlawii resulted in increased cellular granularity and destruction. Scanning electron microscopic (SEM) examination of infected RTG‐2 and AS cultures revealed typical mycoplasmas distributed on cell surfaces and a marked effect on the cell surface topography, characterized by a loss of microvilli and cellular processes. SEM also revealed mycoplasmal contamination that was not detected by culturing. Comparisons of contaminated and uncontaminated RTG‐2 cells showed enhanced (2–100 fold) replication of infectious pancreatic necrosis virus (IPNV) and infectious haematopoietic necrosis virus (IHNV) in the presence of A, laidlawii.
Observations on the intestinal pathology caused by three caryophyllid tapeworms of the white sucker Catostomus commersoni Laécpéde
Authors: HAYUNGA E. G.
Published: April 2006

Abstract. The structure of the parasite‐host interface at the site of attachment was studied for Glaridacris catostomi, G. laruei and Hunterella nodulosa, caryophyllid tapeworms of the white sucker Catostomus commersoni. Light microscope observation of fish infected with H. nodulosa showed a loss of intestinal epithelium and lamina propria, and a chronic inflammatory response characterized by infiltration of lymphocytes and extensive hyperplasia of the submucosal tissue; intestinal pathology associated with G. catostomi and G. laruei was minimal. Electron microscope examination of the parasite‐host interface revealed that in no case does parasite tissue come into direct contact with host tissue. H. nodulosa is separated from host tissue by an amorphous layer of electron lucent material (the ‘eosinophilic matrix’ seen with the light microscope) which appears to act as an adhesive; this material is a secretory product of the scolex glands. In G. catostomi and G. laruei a layer of material separating parasite from host tissue was also found, but it is not clear whether this layer is adhesive or protective.
Nephrocalcinosis in rainbow trout Salmo gairdneri Richardson; the effect of exposure to elevated CO2 concentrations
Authors: SMART G. R. , KNOX D. , HARRISON J. G. , RALPH J. A. , RICHARD R. H. , COWEY C. B.
Published: April 2006

Abstract. Rainbow trout exposed to environmental free C02 concentrations ranging from 12–60 mg/1 for a minimum of 275 days developed nephrocalcinosis. Gross, histopathological and chemical examinations demonstrated that prevalence and severity of nephrocalcinosis increased with increasing CO2 concentrations. The condition was characterized by calcification and granuloma formation in kidney and stomach. Diet, but not water, PO4 ‐P concentration appeared to modify the prevalence and severity at each CO2 concentration tested.
Hepatomas in Atlantic tomcod Microgadus tomcod (Walbaum) collected in the Hudson River estuary in New York
Authors: SMITH C. E. , PECK T. H. , KLAUDA R. J. , MCLAREN J. B.
Published: April 2006

Abstract. Incidental observations of Atlantic tomcod during routine laboratory processing revealed that a portion of the adult population collected during the 1977–78 spawning season had enlarged livers containing dark coloured tumours and other abnormalities. Of the total of 264 livers collected between 16 January and 27 February 1978 and grossly examined for prevalence of abnormalities, 25% appeared to contain neoplastic nodules and hepatocellular carcinoma. One liver contained a massive tumour (7 × 12 mm) that involved approximately 60% of the liver. The exact causes of the high prevalence of hepatocellular carcinoma are unknown but poly‐chlorinated biphenyls (PCBs) are suspected of having a possible role. The Hudson River is known to contain elevated concentrations of PCBs. Twelve tomcod livers from the 1977–78 spawning population representing both normal and hepatoma conditions contained concentrations of PCBs ranging from 10–9 to 98–2 ppm (mean of 37–5 ppm).
The evaluation of piromidic acid as an antibiotic in fish: an in vitro and in vivo study
Authors: KATAE H. , KOUNO K. , TAKASE Y. , MIYAZAKI H. , HASHIMOTO M. , SHIMIZU M.
Published: April 2006

Abstract. The activity of piromidic acid (PA, 8‐ethyl‐5, 8‐dihydro‐5‐oxo‐2‐prior lidinopyrido [2,3–d] pyrimidine‐6‐carboxylic acid) against bacteria in fish was evaluated in vitro and in vivo.

In vitro, PA was effective against a wide range of pathogenic bacteria stocked in this laboratory and freshly isolated from fish. PA was active against organisms showing multiple drug‐resistance and showed no cross‐resistance to chloramphenicol, tetracycline and sulfamonomethoxine.

In vivo, orally administered PA was effective against experimental infections with Aeromonas hydrophila and Vibrio spp. in goldfish and eels. The efficacy of PA against these infections was equal to or higher than that of chloramphenicol, and higher than that of tetracycline. Distribution of PA in the Ash was investigated by bioassay and autoradiography. In the bioassay, orally administered PA was easily absorbed and distributed in the blood and tissues of major organs within 1 h after the administration. Peak levels were attained 2 to 4 h post dosing, and no residue was detected in the blood and tissues 48 h post dosing. The results obtained from the autoradiographic investigation in goldfish were similar to those from the bioassay. Therapeutic levels of PA were well tolerated by fish when administered with feed.
The role of melano‐macrophage centres in iron storage in normal and diseased fish
Authors: AGIUS C.
Published: April 2006

Abstract. The spleen, kidney and liver melano‐macrophage centres of 14 species of clinically normal teleost fish were examined histochemically for ferric iron. Iron was present in varying amounts within the splenic centres of most specimens, but by contrast it was rarely found in the centres of the kidney and the liver.

Under conditions of starvation and in diseased fish, a markedly increased deposition of ferric iron occurred in the splenic centres of nearly all fish examined. By comparison, the iron content in the kidney and liver centres was generally still very low. These results suggest that there exist important functional differences between the pigment centres of different haemopoietic tissues of teleosts.
Studies on the pathogenesis of vibriosis in coho salmon Oncorhynchus kisutch (Walbaum)
Authors: HARBELL S. C. , HODGINS H. O. , SCHIEWE M. H.
Published: April 2006

Abstract. Juvenile coho salmon Oncorhynchus kisutch (Walbaum), cultured in fresh water, were experimentally infected with highly virulent Vibrio anguillarum, and various haematological and biochemical parameters were compared between moribund and non‐infected control fish. In addition, endotoxin, culture supernatant, and cell lysate preparations of V. anguillarum were tested separately and in combination to assess their roles in mediating pathological effects.

The haematocrit, haemoglobin, numbers of red and white blood cells and plasma, total protein, albumin, β2 globulin, chloride, sodium, osmolality and alkaline phosphatase levels were all decreased in infected fish compared to controls. Erythrocyte fragility and plasma glucose, potassium, lactate dehydrogenase (LDH), and glutamic oxaloacetic transaminase (GOT) levels were increased in infected fish.

No mortality nor significant changes in haematocrit or plasma protein occurred in fish injected intraperitoneally with 35 mg/kg (1 mouse LD50) of V. anguillarum endotoxin, with culture supernatant fluid, cell lysate, or with combinations of the three preparations. There was, however, a decrease in plasma protein concentration in coho injected with 355 mg/kg (10 mouse LD50s) of endotoxin, but no mortality nor significant change in haematocrit.
Bath‐immunization—a practical and non‐stressing method of vaccinating sea farmed rainbow trout Salmo gairdneri Richardson against vibriosis
Authors: EGIDIUS E. C. , ANDERSEN K.
Published: April 2006

Abstract. A non‐stressing easily applicable vaccination method against vibriosis in rainbow trout is described. The vaccine consisted of trypsin digested Vibrio anguillarum cells and was administered through a 2 h bath treatment, giving adequate protection in challenge experiments with the same V. anguillarum strain.
Light and electron microscopic observations of sporogenesis in the myxosporida, Ceratomyxa shasta (Noble, 1950)
Authors: YAMAMOTO T. , SANDERS J. E.
Published: April 2006

Abstract. The stages of development leading to sporogenesis of Ceratomyxa shasta (Noble) were investigated by light and electron microscopy. Salmonid fishes were infected by exposing them to water containing the infectious stage and intestinal material was fixed at weekly intervals. Signs of intestinal infection were barely detectable by 7 days following exposure where trophozoites and later developmental forms were present, but by 14 days a large number of pansporoblasts could be detected in varying stages of development. By 21 days the majority of caeca were completely occluded and infection had spread throughout the connective tissues attached to the caeca.

The early developing trophozoites contained two or more nucleated cells within a mother cell. There was some evidence of multiplication of nuclei by fission. The sporoblasts usually contained twelve nucleated cells that gave rise to two groups of six cells (sporonts) and resulted in the formation of two spores in each mother cell. Each spore was formed by two sets of bilaterally arranged cells consisting of the main germinative cell or sporoplasm, the anteriorly placed capsule cells and the outer envelope or spore valve cell that surrounded the others and formed the spore covering.

As the spore matured the two germinative cells interacted with each other by pseudopodial extensions and appeared to fuse to form a diploid cell. The position of the cells laterally and slightly posteriorly to the central suture line formed a bilaterally curved spore. Mature spores when examined with the electron microscope were condensed, dark staining and relatively featureless, with a lateral measurement of 15 μm and an anterior‐posterior measurement of 7μm.
Glugea heraldi n. sp. (Microsporida, Glugeidae) from the seahorse Hippocampus erectus Perry
Authors: BLASIOLA G. C.
Published: April 2006

Abstract. A new species of Microsporida, Glugea heraldi, is described from the seahorse Hippocampus erectus. Measurements of fixed spores and notes on the histopathology of parasitized tissue are given.
Effect of the digenean Isoparorchis hypselobagri (Billet, 1898) on an airbreathing fish Channa punctatus (Bloch) with particular reference to biochemical and haematological changes
Authors: MAHAJAN C. L. , AGRAWAL N. K. , JOHN M. J. , KATTA V. P.
Published: April 2006

Abstract. Morphological, behavioural and haematological changes in Channa punctatus caused by infection with the digenean Isoparorchis hypselobagri are reported. Morphological changes include partial necrosis of fin tissue, scale loss (particularly along the opercula and caudal peduncle) and loss of pigmentation, together with considerable damage to the viscera, especially the gonads, and the abdominal muscles. Behavioural changes include partial or complete loss of equilibrium, irritability and convulsions. Haematological changes observed were a significant decrease in haemoglobin and haematocrit values resulting in hypochromicmacrocytic and normochromicnormocytic anaemia together with an increase in total leucocyte number. Significant decreases in blood glucose level and liver glycogen content were also observed. Some of the changes could be partially compensated by providing a bigger food ration. Compensatory effects were observed for haemoglobin and haematocrit values and leucocyte number. However, an increase in diet could not arrest the significant decrease in blood glucose level and liver glycogen content. The possible effects of parasitism on the utilization and productivity of C. punctatus are discussed.
Distribution, excretion and biotransformation of 14C‐piromidic acid in goldfish Carassius aumtus (L.)
Authors: KATAE H. , KOUNO K. , SEKINE Y. , HASHIMOTO M. , SHIMIZU M.
Published: April 2006

Abstract. The pharmacokinetic and metabolic disposition of piromidic acid (PA) was studied in goldfish orally administered a single dose of 40 mg/kg of PA or 14C‐PA with the following results. PA was rapidly absorbed from the alimentary tract and became widely distributed to give maximal organ and tissue levels mostly after 1 h post dosing. Organ and tissue levels of PA as measured by the radioactivity were 1.4–2.2 times as high as those obtained by the bioassay, though their distribution patterns were similar. PA was partly biotransformed to unconjugated antibacterial metabolites, i.e., α‐OHPA and β‐OHPA and partly to more hydrophilic glucuronides which were excreted into bile. Bioactive metabolites along with PA disappeared almost entirely from the fish within 48 h post dosing. The antibacterial activity of α‐OHPA and β‐OHPA against major pathogenic bacteria isolated from fish showed two to four‐fold greater activity as compared with PA. This pharmacokinetic and metabolic disposition, together with the antibacterial activity of PA and its active metabolites, suggest a possible practical application of PA against bacterial fish diseases.
Occurrence of viral haemorrhagic septicaemia in rainbow trout Salmo gairdneri Richardson reared in sea‐water
Authors: GASTRIC JEANNETTE , DE KINKELIN P.
Published: April 2006

Abstract. Viral haemorrhagic septicaemia (VHS) is reported for the first time in sea‐water cultured rainbow trout. Heavy mortalities with typical signs and lesions A VHS virus (serotype 1) was isolated from the diseased fish. The mortalities were caused only by the VHS virus and 80 days post transfer of trout to sea‐water the mortalities reached 85%, of the initial population.

The disease was experimentally transmitted to rainbow trout, both in sea‐water 3·104 pfu/ml of virus or by intramuscular injection of various doses of VHS1 (7·101 7·104 or 7·104 pfu per fish). Death occurred in all infected groups and started earlier in sea‐water. Typical signs of VHS were observed in moribund fish. Viral multiplication was demonstrated to have occurred in fish organs.
A bacterium with similarities to the redmouth bacterium and Serratia liquefaciens (Grimes and Hennerty) causing mortalities in hatchery reared salmonids in Australia
Authors: LLEWELLYN L. C.
Published: April 2006

Abstract. Blood spots in the eye and haemorrhages in the musculature of the caudal peduncle were the main indication of disease in Australian hatchery reared brook trout Salvelinus fontinalis (Mitchill) and Atlantic salmon Salmo salar L. Mortalities of 0·1‐0·5% per day occurred for 3–4 weeks in fish stocked in circular ponds in the months of February and March when temperatures were falling from 23–11·C. The bacterium belonging to the Family Enterobacteriaceae had similarities with Yersinia ruckeri (the RM bacterium) and Serratia liquefaciens. As a temporary designation SBS was used. It is recommended that its taxonomic position remain sub judice for the present. Inoculation experiments on brook trout and landlocked Atlantic salmon indicated that signs appeared 2–7 days after inoculation and that rainbow trout Salmo gairdneri Richardson were resistant to the disease.
Virus infections of marine fish erythrocytes: electron microscopical studies on the blenny virus
Authors: SMAIL D. A. , EGGLESTONE S. I.
Published: April 2006

Abstract. This paper reports for the first time the application of the direct negative staining technique for the rapid confirmation of the viral nature of blenny‘piscine erythrocytic necrosis (PEN). The virus in negatively stained preparations has an internal core structure which appears in exact opposite contrast to that seen in thin sectioned virus. The resultant images from both negative staining and thin sectioning suggest that the organization of the core is unique amongst intracytoplasmic deoxyriboviruses (ICDVs).
Aetiology of an ulcerative disease in goldfish, Carassius auratus (L.): experimental induction of the disease
Authors: ELLIOTT DIANE G. , SHOTTS E. B.
Published: April 2006

Abstract. Infection experiments were conducted to determine the primary aetiology of an ulcerative disease in goldish, Carassius auratus (L.). Goldfish were exposed to atypical Aeromonas salmonicida and A. hydrophila, previousl y isolated from cutaneous ulcers, and to 04 5 μm filtrates of cutaneous ulcers and kidneys from diseased fish. Fish were exposed to each preparation by intraperitoneal, intramuscular or subcutaneous injection and by a method in which a small patch of scales was removed from each side of the fish and the inoculums applied. Most of the fish injected with A. salmonicida died without developing coetaneous ulcers; however, ulcers were induced in five of the ten fish exposed by the scale removal technique. Exposure to ultra filtrates or A. hydrophila did not result in consistent ulcer formation o r death. Additional experiments showed that a 30‐min exposure of goldfish, without prior treatment, to water containing 3 × 105 colony forming units (cfu/ml) of A. salnumicida was sufficient to produce cutaneous lesions in nine often fish exposed. Multiple lesions were produced in most fish and A. salmonicida was consistently recovered. Fish exposed by similar waterborne challenge s to 6·2 × 106 cfu/ml of A. hydrophila or to 7·2 × 106 cfu/ml of another lesion isolate identified as a member of the A. hydrophila complex produced no lesions, eve n when scales were removed. The studies demonstrate that atypical A. salmonicida can initiate cutaneous lesion s characteristic of ulcerative disease, while A. hydrophila and an A. hydrophila complex organism cannot.
Studies on the morphology of Uronema marinum Dujardin (Ciliatea: Uronematidae) with a description of the histopathology of the infection in marine fishes
Authors: CHEUNG P. J. , NIGRELLI R. F. , RUGGIERI G. D.
Published: April 2006

Abstract. A normally free‐living hymenostomatid ciliate was found to be the cause of heavy infections of gills, viscera and body muscle in Atlantic and Pacific marine fishes kept in the New York Aquarium. Of special interest is the fact that the parasites, usually with food vacuoles filled with blood cells and cellular debris, caused extensive damage to the body muscle; the other infected organs showed no characteristic tissue reactions. The immediate cause of death is attributed to the exceptional load of the parasite on the gills, thus interfering with normal respiratory function.

The ciliate, isolated from a recent outbreak, is described in detail, and shows many characteristics of Uronema marinum Dujardin, a species that has been reported as free‐living in salt water; the form reported here differs from the type and other members included in this species, by the presence of less than three rows of bipolar meridians. This facultative parasite is described in detail and compared with other genera.
Histological effects of prolonged sublethal hypoxia on channel catfish Ictalurus punctatus (Rafinesque)
Authors: SCOTT A. L. , ROGERS W. A.
Published: April 2006

Abstract. A vacuum degassing apparatus was used to subject channel catfish Ictalurus punctatus (Rafinesque) to sublethal hypoxia for 24, 48 or 72 h. Spleen, liver, gills, anterior kidney and posterior kidney from the catfish exhibited histopathological changes that included necrosis, hyperaemia, oedema, haemorrhage, hyperplasia and hypertrophy. Of the organs examined, gills were most affected by the hypoxic conditions. After 5 days of reacclimatization to normoxic conditions, channel catfish continued to exhibit histopathological effects of prolonged hypoxia.
Kidney tumour virus—tumour or mycobacterial tubercle?
Authors: BECKWITH D. G. , MALSBERGER R. G.
Published: April 2006

Abstract. Bacteriologically sterile filtrates of ‘tumorous’ fish elicited formation of ‘tumours’in vivo which were morphologically indistinguishable from those described by Wessing & Bargen (1959). Attempts to isolate the putative aetiologic ‘Virus’ in primary and established cell cultures failed. When the lesions were examined for other compatible aetiologies, acid‐fast stains revealed acid‐fast bacilli and cultures grew Mycobacterium fortuitum. It is suggested that the ‘kidney tumour virus’ is actually soluble mycobacterial cell‐fractions capable of eliciting tubercle formation in vivo.
Amyloodinium ocellatum (Brown, 1931) (Dinoflagellida) infestations in cultured marine fish at Eilat, Red Sea: epizootiology and pathology
Authors: PAPERNA I.
Published: April 2006

Abstract. Since 1977, repeated outbreaks of infestation by Amyloodinium ocellatum (Dinoflagellida) in cultured gilthead bream Sparus aurata L. and seabass Dicen‐trarchus labrax (L.) resulted in sporadic and mass mortalities. Fingerlings and yearlings as well as breeders were affected and, since 1978, larval and post‐larval S. aurata in the hatchery. Infestations in juvenile and breeder fish were located predominantly on the gills and mucosal integument but in larval fish only the skin rather than the gills was infested. Histopathological changes of the infested gills are described. Vacuolar degeneration of the cells penetrated by the parasites’ rhizoids was evident at the site of attachment and cloudy swelling was apparent in the surrounding epithelial cells. In heavy infestations the entire epithelium of the gill filaments underwent hyperplasia with consequent fusion of the lamellae. Where hyperplasia was extensive the cells gradually degenerated while the inner epithelial layer showed distinct spongiosis and in some cases completely disintegrated. All heavily infested gills lacked mucous cells.
Comparative studies on the immune system of fishes and amphibians: antigen localization in the carp Cyprinus carpio L.
Authors: SECOMBES C. J. , MANNING MARGARET J.
Published: April 2006

Abstract. Antigen localization studies in the mirror carp Cyprinus carpio were carried out using a soluble antigen, human gamma globulin and a cellular bacterial antigen, Aeromonas salmonicida. Antigen was detected using direct single layer and indirect double layer immunofluorescent techniques, respectively. A study of the spleen, pronephros, mesonephros, liver and thymus at various times after administration of the antigen showed that fluorescence occurs mainly in the ellipsoids of the spleen and in the haemopoietic parenchyma of the pronephros and mesonephros and reaches its greatest intensity when antibody titres are relatively high. A direct comparison with antigen localization in the clawed toad Xenopus laevis, has enabled us to analyse possible evolutionary trends towards the complex dendritic retention of antigen seen in the higher vertebrates.