Epidemiology of squamous cell carcinomas in rudd Scardinius erythrophthalmus from SE Ireland

An epidemiological study was carried out to investigate the possible aetiology of squamous cell carcinomas which occur in a population of rudd Scardinius erythrophthalmus (L.) from Lough Aderry in south-east Ireland. A total of 1343 rudd were sampled from Lough Aderry and 2 nearby small lakes in spring, summer, autumn, and winter over 2 yr, 1986 to 1988. Fish were weighed, measured, sexed, aged, and examined for lesions. Water quality parameters and natural radioactivity were assessed as possible influencing factors in the disease. The prevalence of squamous cell carcinoma was 6.1% overall, with no significant difference between the lakes, seasons or years. Both male and female fish were affected, of ages from 1+ to 5+ yr. No fish of 6+ or 7+ yr was found with tumours, indicating that the neoplasm caused premature death. The female:male sex ratio of rudd with tumours was higher than that of healthy rudd overall, suggesting that males are more susceptible to the neoplasm. Of the parasites observed, Posthodiplostomum cuticola was common, but rarely found in rudd with tumours. Sphaerospora sp.was also common, but not in sufficient densities for statistical inference, and Argulus sp. was present on 7 fish. No viral particles were found. Natural radiation levels in the vicinity of the lakes were low. The lakes sampled are in an agricultural catchment, and the waters were eutrophic. While rudd are tolerant, it is likely that environmental conditions were stressful at least some of the time, with possible consequences for the immunocompetence of the rudd. The aetiology of the carcinoma is still unknown, but the possibilities of carcinogenic compounds resulting from the high nutrient levels, or of carcinogenic algal toxins produced during algal blooms, should be examined.     

On the orientation of stripes in fish skin patterning

This paper is focused on the study of the stripes orientation in the fish skin patterns. Based on microscopic observations of the pigment cells behavior at the embryonic stage, the key aspects of the pigmentation process are implemented in an experimental reaction-diffusion system. The experiment consists of a photosensitive Turing pattern of stripes growing directionally in one direction with controlled velocity. Different growth velocities of the system rearrange the stripes in the same three possible orientations observed in the skin of the colored fishes: parallel, oblique, and perpendicular. Our results suggest that the spreading velocity of the pigment cells in the fish dermis selects the orientation in the patterning processes.     

Ex Vivo Infection of Murine Epidermis with Herpes Simplex Virus Type 1

To enter its human host, herpes simplex virus type 1 (HSV-1) must overcome the barrier of mucosal surfaces, skin, or cornea. HSV-1 targets keratinocytes during initial entry and establishes a primary infection in the epithelium, which is followed by latent infection of neurons. After reactivation, viruses can become evident at mucocutaneous sites that appear as skin vesicles or mucosal ulcers. How HSV-1 invades skin or mucosa and reaches its receptors is poorly understood. To investigate the invasion route of HSV-1 into epidermal tissue at the cellular level, we established an ex vivo infection model of murine epidermis, which represents the site of primary and recurrent infection in skin. The assay includes the preparation of murine skin. The epidermis is separated from the dermis by dispase II treatment. After floating the epidermal sheets on virus-containing medium, the tissue is fixed and infection can be visualized at various times postinfection by staining infected cells with an antibody against the HSV-1 immediate early protein ICP0. ICP0-expressing cells can be observed in the basal keratinocyte layer already at 1.5 hr postinfection. With longer infection times, infected cells are detected in suprabasal layers, indicating that infection is not restricted to the basal keratinocytes, but the virus spreads to other layers in the tissue. Using epidermal sheets of various mouse models, the infection protocol allows determining the involvement of cellular components that contribute to HSV-1 invasion into tissue. In addition, the assay is suitable to test inhibitors in tissue that interfere with the initial entry steps, cell-to-cell spread and virus production. Here, we describe the ex vivo infection protocol in detail and present our results using nectin-1- or HVEM-deficient mice.     

Larval skin of the flathead sole,Hippoglossoides elassodon

Summary The skin of newly-hatched larval flathead sole, Hippoglossoides elassodon, is described by light and electron microscopy. The epidermis is usually two cells thick and shows differentiation into both squamous and mucous cells. The squamous cells are characterized by numerous cytoplasmic filaments, typical desmosomes, and lack of keratinization; the mucous cells are distended with mucous droplets, which appear to originate in the Golgi apparatus. A basement membrane is present, although thinner and less dense than that of older fish, and the dermis contains loose formations of collagen and pigment cells.This work was supported in part by USPHS research grant CA-08158 from the National Cancer Institute.     

Scanning with Macroaggregates of Radioiodinated Human Serum Albumin as an Adjunct to Celiac Arteriography: A Preliminary Communication

When macroaggregates of radioiodinated human serum albumin are injected into the celiac axis at the conclusion of celiac arteriography, satisfactory scans in which hepatic, splenic and pancreatic-duodenal out-lines are present can be obtained. Following preliminary experiments in dogs, five patients were scanned after celiac arteriography and injection of macroaggregates. No adverse reactions were noted and good delineation of upper abdominal viscera was possible. One case demonstrated good clinical-pathological correlation, in that tumour site and extent, and cirrhosis were predictable from the antemortem scan.     

Cytomorphology of primary small-cell (Merkel-cell) carcinoma of the skin in fine needle aspirates

The histologic appearance of primary small-cell carcinoma of the skin (the so-called Merkel-cell tumor) is similar to other small-cell tumors that may metastasize to the dermis. Significance has been placed on the electron microscopic appearance of this tumor since the ultrastructural features of this neoplasm are helpful in distinguishing it from most of the other neoplasms considered in the differential diagnosis. To determine whether any additional morphologic criteria might exist to distinguish this neoplasm, the fine needle aspirate appearance of a primary small-cell carcinoma of the skin was studied and compared to that of similar preparations of other small-cell tumors that could potentially involve the dermis. Cells of this unusual tumor were round and showed neither cohesiveness nor nuclear molding. Mitoses were numerous. The chromatin pattern was bland. The cytologic features of this tumor can aid in the distinction of primary small-cell carcinoma of the skin from other metastatic small-cell neoplastic lesions in the dermis of adults.     

Opposite regulation of tenascin-C and tenascin-X in MeLiM swine heritable cutaneous malignant melanoma

Interactions between tumour cells and surrounding extracellular matrix (ECM) influence the growth of tumour cells and their ability to metastasise. It is thus interesting to compare ECM composition in tumours and healthy tissues. Using the recently described MeLiM miniature pig model of heritable cutaneous malignant melanoma, we studied the expression of two ECM glycoproteins, the tenascin-C (TN-C) and tenascin-X (TN-X), in normal skin and melanoma. Using semiquantitative RT-PCR, we observed a 3.6-fold mean increase of TN-C RNAs in melanoma compared to normal skin. Both stromal and tumour cells synthesise TN-C. On the contrary, TN-X RNAs decreased 30-fold on average in melanoma. This opposite regulation of TN-C and TN-X RNAs was confirmed at the protein level by indirect immunofluorescence. Whereas pig normal skin displayed a discrete TN-C signal at the dermo-epidermal junction, around blood vessels and hair bulbs, the swine tumour showed enhanced expression of TN-C in these areas and around stromal and tumour cells. In contrast, normal skin showed a strong TN-X staining at the dermo-epidermal junction and in the dermis, whereas this signal almost completely disappeared in the tumour. The results presented here describe a dramatic alteration of the ECM composition in swine malignant melanoma which might have a large influence on tumourigenesis or invasion and metastasis of melanoma cells.     

A real-time predictive simulation of abdominal viscera positions during quiet free breathing

Prediction of abdominal viscera and tumour positions during free breathing is a major challenge from which several medical applications could benefit. For instance, in radiotherapy it would reduce the healthy tissue irradiation. In this paper, we present a new approach to predict real-time abdominal viscera positions during free breathing. Our method needs an abdo-thoracic 3D preoperative CT or MR image, a second one limited to the diaphragmatic area, and a tracking of the patient's skin position. First, a physical analysis of the breathing motion shows it is possible to predict accurately abdominal viscera positions from the skin position and a modelling of the diaphragm motion. Secondly, a quantitative analysis of the skin and organ motion allows us to define the demands our real-time simulation has to fulfill. Then, we present in detail all the necessary steps of our original method to compute a deformation field from data extracted in both 3D preoperative image and skin surface tracking. Finally, experiments carried out with two human data show that our simulation model predicts abdominal viscera positions, such as liver, kidneys or spleen, at 50 Hz with an accuracy within 2-3 mm.     

Pathogenesis of experimentally induced bacterial cold water disease in ayu Plecoglossus altivelis

Ayu Plecoglossus altivelis were experimentally infected with Flavobacterium psychrophilum, which is the causative agent of bacterial cold water disease (CWD). The fish infected by immersion usually died within an hour after they became moribund. The blood volume and haematocrit values of moribund fish were low, while those values of many infected fish that were not moribund were in the range of controls. Most of the affected fish in the immersion-infected groups had ulcerative lesions on their lower jaw. No histological evidence of haemolysis was observed. These results suggest that rapid bleeding occurred through ulcerative lesions, probably causing hypoxia which killed the fish. Ulcerative lesions developed on the dorsal skin when this area had been slightly abraded artificially prior to immersion challenge. Histologically, F. psychrophilum was initially found on the skin that had microscopic injuries, but not on normal skin. The bacterium then entered the dermis and migrated through connective tissues. The lesions subsequently expanded into the underlying musculature through the myosepta, developed necrotic myositis and formed externally open ulcers. Only in later stages of infection did mild lesions develop in the internal organs and the gill, probably caused by the bacterium migrating through blood vessels. This suggests that infection with CWD through the gill or digestive tract is unlikely. Virtually no open lesions were found in ayu challenged by intramuscular injections except at the injection sites. The results suggest that skin injuries are major portals of entry for F. psychrophilum in ayu, and the bacterium has affinity for collagenous connective tissues.     

Observations on a tissue response within the body cavity of fish infected with the plerocercoid larvae of Ligula intestinalis (L.) (Cestoda: Pseudophyllidea)

Infection of certain species of cyprinid fish with the plerocercoid larva of the cestode Ligula intestinalis is accompanied by a host tissue response.
The tissue reaction is evident in roach Rutilus rutilus as young as three months. An initial cellular infiltration is followed by the laying down of sheets of connective tissue. A case of calcification is described in a single infected rudd Scardinius erythrophthalmus .     

First Finding of Ornithodiplostomum scardinii (Schulman, 1952) Sudarikov et Kurotschkin, 1968 (Trematoda,Diplostomidae) in Rybinsk Reservoir

During a parasitological survey of nonnative fish species—rudd Scardinius erythrophthalmus—in the Rybinsk Reservoir, the metacercariae Ornithodiplostomum scardinii were found in its brain. This is the first find of this helminth in the Upper Volga basin. The rudd was infected with the prevalence 31.3%, with an intensity of 1–12 parasites per fish. Data on the current distribution of the trematode O. scardinii in the Volga River basin are provided.     

Bacterial involvement in a saddleback disease of the reef silverside, At henna harringtonensis Goode (Pisces: Atherinidae) from Bermudan waters

Saddle-shaped skin lesions commonly occurring in both wild and captive Bermudan reef silversides yielded a mixed infection of motile and non-motile Gram-negative cells of Acinetobacter calcoaceticus, Aeromonas hydrophila, Pseudomonas sp., Vibrio parahaemolyticus and a myxobacterial-like strain. Bacteria occurred as almost pure microcolonies and mixed clumps on proximal scale and fin ray surfaces, in intercellular epidermal spaces, on perimysium of fin erector muscle myomeres and on eroded dorsal fin rays and their intact membranes, but neither on healthy areas of the skin nor within muscle cells. Effects were epithelial destruction and liquefactive necrosis of myomeres, and raising and sloughing of Malpighian cells, scales and dermis. Host response was minimal, consisting of infiltration of a few lymphocytes and macrophages. The fish pathogenic dinoflagellate Amyloodinium ocellatum was seen in one fish with a saddle lesion and caused muscle cell lysis, as evidenced by cloudy cell swelling. Antibiotic sensitivity tests showed increased drug resistance with mixed bacterial types compared to that of single pure isolates. This suggests that alternatives to chemotherapy for control of bacterial fish diseases is appropriate, because most are probably caused by mixed infections.     

A search for introgressive hybridization in the rudd, Scardinius erythrophthalmus (L.), and the roach, Rutilus rutilus (L.)

Rudd, roach and their hybrids from an interbreeding population at Norwich were examined electrophoretically for seven enzymes; an examination of pharyngeal teeth supplemented the data. The rudd were compared to rudd from Lake Trawsfynydd, Wales, a lake free from roach. No differences were observed between the rudd from the two localities and no evidence was found of introgression within the fish from Norwich.     

Spontaneous uterine granular cell tumour in a Fischer 344 rat.

The microscopic features of a spontaneous uterine granular cell tumour in a Fischer 344 rat are described. The location of the tumour is novel for the rat. The neoplasm is characterized by the presence of cells with cytoplasmic granules which were PAS positive and diastase resistant. Electron microscopy and immunohistochemistry results are presented and the origin of the tumour is discussed.     

Schistosoma mansoni,S. haematobium,and S. japonicum: early events associated with penetration and migration of schistosomula through human skin

Migratory pattern of schistosomula of Schistosoma mansoni, S. haematobium, and S. japonicum through human skin were analyzed in skin organ cultures. These studies showed that the schistosomula of S. mansoni and S. haematobium has similar migratory patterns through human skin. During the first 24h after infection nearly 90% of S. mansoni and S. haematobium schistosomula were present only in the epidermis. Majority of the schistosomula were found in the dermis only after 48h and they appear to reach the dermal vessels around 72h after infection. Migratory pattern of S. japonicum on the other hand was significantly different from the other two species in that over 90% of the parasites had already reached the dermis within the first 24h and schistosomula were present in the dermal vessels within 2h after infection. Analysis of the cytokine pattern at 8h after infection by a macro gene array and RT-PCR analysis showed that out of 24 different cytokines analyzed only IL-1ra, IL-10, and TNF-alpha were increased in the human skin following infections with S. mansoni and S. haematobium, whereas, after infection with S. japonicum there was significant increases in IL-1beta, IL-1ra, IL-2, IL-6, IL-8, IL-10, IL-15, IL-18, and TNF-alpha. Immunohistochemical analysis of epidermal sheets showed focal accumulation of HLA-DR(+) cells in areas where schistosomula of S. mansoni had entered the human skin.     

The population biology of two species of eyefluke, Diplostomum spathaceum and Tylodelphys clavata, in roach and rudd

Infections of roach ( Rutilis rutilus ), and rudd ( Scardinius erythrophthalmus ), by the eyeflukes Diplostomun spathaceum and Tylodelphys clavata were studied in a lake over a three year period. T. clavata first appeared at the beginning of the study. Roach were heavily infected by both parasites, whereas the rudd contained very few specimens of either species. A small number of roach-rudd hybrids were also examined, and appeared to have a susceptibility intermediate between the parental types.
Levels of T. clavata in roach increased throughout the study. This parasite had a life span of a year or less in the fish, and was continuously lost from the population. This loss was balanced by a minor infection period in April/May and a major one extending from August until January. The fish continued to accumulate infections until they reached a size of about 130 mm, but thereafter intensity fluctuated about the level reached.
D. spathaceum infections similarly increased throughout the period of study, and there was a suggestion of a wave of infection in the spring. This parasite has a much longer life span, and levels of infection increased with fish size, only falling in the largest, and therefore oldest, hosts.
The major changes in the parasite populations in the roach were reflected, to a lesser extent, in the rudd. Both species were over-dispersed, but the data from roach was too heterogeneous to fit to any theoretical models, whereas that from the rudd was found to conform to a Negative Binomial distribution.     

The structure of the integument of the sea cucumber,Thyone briareus

The integument and podia of the sea cucumber Thyone briareus were examined by bright field and electron microscopy. The epidermal surface was found to be covered by an acellular, PAS positive cuticle which appeared to be secreted by the underlying epidermal cells. Although the superficial portion of the cuticle contains numerous fine filaments, their ultrastructure bears no resemblance to collagen fibers. The epidermal cells are widely spaced and have long apical processes that extend along the under surface of the cuticle forming a contiguous epithelium. The apical expansions of the epidermal cells are attached to one another by means of septate desmosomes which may run continuously around all epidermal cells. Special attachment structures within these apical expansions appear to bind the cuticle to the dermis. The epidermal cells and their apical expansions are separated from the dermis by an 800 Å thick basement membrane. Granule containing cells in the upper dermis send processes up to the cuticle where they are bound to the typical epidermal cells by septate desmosomes. The abundant membrane bound granules of the cells enter villous-like processes which pass through the cuticle. The function of these cells may be to produce an adhesive material on the podia or they may be pigment cells. The thick dermis consists of a superficial zone, containing largely ground substance; a middle or laminated zone containing laminae of collagen fibers arranged in an orthogonal fashion; and a hypodermis consisting largely of ground substance and reticular fibers. Fibroblasts are abundant in the superficial dermis and between the collagen laminae. Wandering coelomocytes, or morula cells, accumulate between the collagen laminae and in the hypodermis. They may also become an integral part of the epidermis by forming septate desmosomes with epidermal cells. Morula cells contain highly specialized spherules whose tinctorial properties and electron microscopic appearance suggest that they contain protein and mucopolysaccharide.     

The skin as interface in the transmission of arthropod-borne pathogens

Animal skin separates the inner world of the body from the largely hostile outside world and is actively involved in the defence against microbes. However, the skin is no perfect defence barrier and many microorganisms have managed to live on or within the skin as harmless passengers or as disease-causing pathogens. Microbes have evolved numerous strategies that allow them to gain access to the layers underneath the epidermis where they either multiply within the dermis or move to distant destinations within the body for replication. A number of viruses, bacteria and parasites use arthropod vectors, like ticks or mosquitoes, to deliver them into the dermis while taking their blood meal. Within the dermis, successful pathogens subvert the function of a variety of skin resident cells or cells of the innate immune system that rush to the site of infection. In this review several interactions with cells of the skin by medically relevant vector-borne pathogens are discussed to highlight the different ways in which these pathogens have come to survive within the skin and to usurp the defence mechanisms of the host for their own ends.     

Fibroblast subpopulations: a developmental approach of skin physiology and ageing

Skin is an organ whose function is far beyond a physical barrier between the inside and the outside of the body. Skin as the whole organism is subjected to ageing which concerns skin mostly in its dermal and deepest component which is also its matricial component. The dermis is a tissue rich in matricial elements and poor in cellular content and it is generally admitted that modifications occurring in the matrix are those which mostly contribute to skin ageing, by altering its biomechanical properties. Therefore it is common to address questions related to skin ageing by considering alterations in matrix molecules like collagen. Actually the dermis is a complex tissue both matricial and cellular and is divided between a superficial dermis close to epidermis and a deep dermis much thicker and histologically different. Several years ago we have undertaken investigations related to fibroblasts which are the cells responsible for the formation and maintenance of the dermis, aiming at isolation, culture and characterization of the fibroblasts from the superficial dermis also called papillary dermis and fibroblasts from the deep dermis also called reticular dermis. We were able to show that these fibroblasts in classical culture on plastic exhibit very different morphologies associated with different secretion properties and we have confirmed and expanded such observations revealing different phenotypes by incorporating these cells in reconstructed skin which allows the reproduction of a three-dimensional architecture recalling skin in vivo especially after grafting onto the nude mouse. We also raise the question of how these two dermal regions appear during the formation of the dermis and the question of their fate during ageing. Progress in solving these questions would certainly appear to be very useful for a better understanding of skin physiology and ageing and would hopefully provide new strategies in anti-ageing research.     

Effects of contrasting omnivorous fish on submerged macrophyte biomass in temperate lakes: a mesocosm experiment

1. Freshwater fish can affect aquatic vegetation directly by consuming macrophytes or indirectly by changing water quality. However, most fish in the temperate climate zone have an omnivorous diet. The impact of fish as aquatic herbivores in temperate climates therefore remains unclear and depends on their dietary flexibility. 2. We tested the effects of a flexible omnivore and an herbivore on aquatic vegetation by comparing the effects of rudd (Scardinius erythrophthalmus, the most herbivorous fish in temperate climates) with grass carp (Ctenopharyngodon idella) in a mesocosm pond study. Exclosures distinguished herbivorous effects of fish on submerged macrophytes from indirect effects through changes in water quality, whereas stable isotope food‐web analysis provided information on fish diets. 3. We hypothesised that rudd, with its flexible diet and preference for animal food items, would only indirectly affect macrophytes, whereas grass carp, with its inflexible herbivorous diet, would directly affect macrophyte biomass. 4. Only grass carp significantly reduced macrophyte biomass through consumption. Rudd had no effect. Food‐web analysis indicated that rudd predominantly consumed animal prey, whereas grass carp included more plants in their diet, although they also consumed animal prey. Grass carp significantly affected water quality, resulting in lowered pH and increased N‐NH₄ concentrations, whereas more periphyton growth was observed in the presence of rudd. However, the indirect non‐herbivorous effects of both fish species had no effect on macrophyte biomass. 5. Both fish species should be considered as omnivores. Despite the fact that rudd is the most herbivorous fish in the western European climate zone, its effect on submerged macrophyte biomass is not substantial at natural densities and current temperatures.