Suspected necrolytic migratory erythema associated with chronic hepatopathy in a cat

A cat presenting with generalised hypotrichosis and crusts on the feet and tail was found to have an unusual chronic hepatopathy. There was also evidence of a chronic small intestinal disease which went undiagnosed. Necrolytic migratory erythema was suspected based on clinical findings and dermatohistopathology, and an association with the chronic hepatopathy was suggested. This is the first report of such an association in a cat. Serum zinc, amino acids and essential fatty acids were analysed, and medical treatment was given with equivocal efficacy.     

The dynamics of zooxanthellae populations: A long-term study in the field

Coral bleaching characterized by the expulsion of symbiotic algae (zooxanthellae) is an increasing problem worldwide. Global warming has been implicated as one cause, but the phenomenon cannot be fully comprehended without an understanding of the variability of zooxanthellae populations in field conditions. Results from a 6-year field study are presented, providing evidence of density regulation but also of large variability in the zooxanthellae population with regular episodes of very low densities. These bleaching events are likely to be part of a constant variability in zooxanthellae density caused by environmental fluctuations superimposed on a strong seasonal cycle in abundance.     

Edge effects and the extinction of populations inside protected areas

Theory predicts that small populations may be driven to extinction by random fluctuations in demography and loss of genetic diversity through drift. However, population size is a poor predictor of extinction in large carnivores inhabiting protected areas. Conflict with people on reserve borders is the major cause of mortality in such populations, so that border areas represent population sinks. The species most likely to disappear from small reserves are those that range widely-and are therefore most exposed to threats on reserve borders-irrespective of population size. Conservation efforts that combat only stochastic processes are therefore unlikely to avert extinction.     

Pleiotropy and the preservation of perfection

A mathematical model is presented in which a single mutation can affect multiple phenotypic characters, each of which is subject to stabilizing selection. A wide range of mutations is allowed, including ones that produce extremely small phenotypic changes. The analysis shows that, when three or more characters are affected by each mutation, a single optimal genetic sequence may become common. This result provides a hypothesis to explain the low levels of variation and low rates of substitution that are observed at some loci.     

An In Vitro Biomechanical Comparison of an Interlocking Nail System and Dynamic Compression Plate Fixation of Ostectomized Equine Third Metacarpal Bones

OBJECTIVE: To compare the mechanical properties of two stabilization methods for ostectomized equine third metacarpi (MC3): (1) an interlocking nail system and (2) two dynamic compression plates. Animal or Sample Population-Ten pairs of adult equine forelimbs intact from the midradius distally. METHODS: Ten pairs of equine MC3 were divided into two test groups (five pairs each): caudocranial four-point bending and torsion. Interlocking nails (6 hole, 13-mm diameter, 230-mm length) were placed in one randomly selected bone from each pair. Two dynamic compression plates one dorsally (12 hole, 4.5-mm broad) and one laterally (10 hole, 4.5-mm broad) were attached to the contralateral bone from each pair. All bones had 1 cm mid-diaphyseal ostectomies. Five construct pairs were tested in caudocranial four-point bending to determine stiffness and failure properties. The remaining five construct pairs were tested in torsion to determine torsional stiffness and yield load. Mean values for each fixation method were compared using a paired t-test within each group. Significance was set at P<.05. RESULTS: Mean (+/-SEM) values for the MC3-interlocking nail composite and the MC3-double plate composite, respectively, in four-point bending were: composite rigidity, 3,454+/-407.6 Nm/rad and 3,831+/-436.5 Nm/rad; yield bending moment, 276.4+/-40.17 Nm and 433.75+/-83.99 Nm; failure bending moment, 526.3+/-105.9 Nm and 636.2+/-27.77 Nm. There was no significant difference in the biomechanical values for bending between the two fixation methods. In torsion, mean (+/-SEM) values for the MC3-interlocking nail composite and the MC3-double plate composite were: composite rigidity, 124.1+/-16.61 Nm/rad and 262.4+/-30.51 Nm/rad; gap stiffness, 222.3+/-47.32 Nm/rad and 1,557+/-320.9 Nm/rad; yield load, 94.77+/-7.822 Nm and 130.66+/-20.27 Nm, respectively. Composite rigidity, gap stiffness, and yield load for double plate fixation were significantly higher compared with interlocking nail fixation in torsion. CONCLUSIONS: No significant differences in biomechanical properties were identified between an interlocking nail and double plating techniques for stabilization of ostectomized equine MC3 in caudocranial four-point bending. Double plating fixation was superior to interlocking nail fixation in torsion.     

Aetiology of an ulcerative disease in goldfish Carassius auratus (L.): microbiological examination of diseased fish from seven locations

Abstract. A comparative diagnostic study was conducted on goldfish, Carassius auratus (L.), with a cutaneous ulcerative disease from five locations in the United States and one each in England and Japan. Fish were examined for parasites, viruses and bacteria. Fish from all locations examine d were infested by ectoparasites; no single parasite species was common to all locations. No virus-associated cytopathology was observed in fathead minnow (FHM) or adult goldfish (CAR) monolayer cell cultures inoculated with homogenates of cutaneous lesions, kidneys and livers from diseased fish. The only bacterium cultured from fish from all locations was an atypical, often late-pigmenting strain of Aeromonas salmonicida . This organism was isolated from 64 of 83 (77%) of the total lesions cultured and was most prevalent in early lesions. A second commonly isolated organism was Aeromonas hydrophila , which was cultured from fish at four of the seven locations and from 28 (34%) of the total lesions cultured. A. hydrophila was most prevalent in terminal lesions. From these studies it was concluded that A. salmonicida was the probable cause of ulcers noted In the cases examined an d that A. hydrophila was a secondary invader.     

A continuous, underway fish egg sampler

We describe a method to sample the highly contagious distribution of pelagic fish eggs. CUFES, the continuous, underway fish egg sampler, consists of a submersible pump, concentrator, electronics and sample collector. This system operates continuously and under nearly all sea conditions, providing a real-time estimate of the volumetric abundance of pelagic fish eggs at pump depth, usually 3 m. CUFES-derived estimates of volumetric abundance agree well with those from nets towed at pump depth and with areal abundance estimated from vertically integrated plankton tows. CUFES has been used successfully to sample the eggs of menhaden, pinfish, sardine, and anchovy off the coasts of the eastern and western United States and South Africa. Two large patches of eggs of the Atlantic menhaden were sampled off North Carolina in winter 1993–94, had a linear scale of 5–10 km, and were found in waters between the Gulf Stream and mid-shelf front. Spawning location may be related to bathymetry. CUFES is now being used to estimate spawner biomass by the daily egg production method. An optical plankton counter provided accurate estimates of the number of Atlantic menhaden eggs sample by CUFES.     

Estimating the quantitative essential amino acid requirements of striped bass Morone saxatilis, using fillet A/E ratios

In order to determine the essential amino acid requirements (EAA) of striped bass Morone saxatilis , fillets were analysed to ascertain the relative amino acid concentrations for determining A/E ratios ((EAA/total EAA) × 1000)). Analysis of the striped bass fillets yielded the following concentrations of essential amino acids (g kg^–1) and A/E ratios, respectively: arginine, 12.5, 115; histidine, 5.1, 47; isoleucine, 8.0, 74; leucine, 17.1, 157; lysine, 20.2, 186; methionine + cysteine, 9.2, 85; phenylalanine + tyrosine, 16.0, 147; threonine, 9.8, 90; tryptophan, 1.9, 18; and valine, 9.1, 84. In two experiments, diets with graded levels of EAA were fed to striped bass weighing 111 ± 3 g and 790 ± 122 g per fish, respectively. In both experiments, the dietary A/E ratios were maintained in the same relative concentrations as determined in the striped bass fillets. Statistical analysis of weight gains, feed conversions and nitrogen balance indicated significant differences ( P  < 0.05) between treatments. Non-linear regression analysis of the response criteria pooled from both experiments yielded the following estimates of dietary EAA requirements (g kg^–1 dry diet) when digestible energy equalled 13.39 MJ kg^–1 diet: arginine, 14; histidine, 6; isoleucine, 9; leucine, 19; lysine, 22; methionine + cysteine, 10; phenylalanine + tyrosine, 17; threonine, 11; tryptophan, 3; and valine, 10. The use of fillet A/E ratios allows for the rapid estimation of quantitative EAA requirements and the development of species specific diets for new aquaculture species. The data presented here are the first to simultaneously describe all the dietary EAA requirements for M. saxatilis.