BACTERIAL ENDOCARDITIS WITH THROMBUS FORMATION AND ABSCESSATION IN A HORSE

A 2.5 year old Appaloosa stallion with progressive weight loss and a heart murmur was diagnosed as having vegetative endocarditis of the right atrioventricular valves with a mass in the right atrium. The ultrasonographic appearance of the lesion was characterized by extreme reverberation. On postmortem examination, a 9 cm diameter thrombus was found within the right atrium and auricle, occupying approximately 80% of the chamber volume. Additionally, a lenticular abscess extended throughout the parietal cusp of the right atrioventricular valve. Histologic examination revealed that the lesions were septic with numerous gram positive cocci in short chains, suggestive of Streptococcus equi , and gram negative rods.     

Segmental axonopathy of Merino sheep in New Zealand

AIM: To investigate an axonopathy of Merino sheep that caused progressive hindlimb ataxia and slight to moderate paresis, with the purpose of understanding its pathogenesis.

METHODS: Tissues were fixed in buffered paraformaldehyde or paraformaldehyde and glutaraldehyde, processed into wax and epoxy resin, respectively, and examined by light and electron microscopy. Fresh frozen spinal cord and trigeminal nerve roots were subjected to homogenisation, centrifugation and two-dimensional electrophoresis. Selected protein spots were identified using matrix-assisted laser desorption ionisation (MALDI) mass spectrometry.

RESULTS. By light microscopy, there were large pale foamy spheroidal axonal swellings affecting peripheral as well as central axons. By electron microscopy, these were shown to contain many membrane-bound vesicles. The main abnormalities in expressed proteins involved cytoskeletal elements and myosin heavy chain, the latter interpreted as associated with the molecular motor myosin Va.

CONCLUSIONS: The disorder is the same as that described in Merinos in Australia as segmental axonopathy, and believed to have an inherited aetiology. The lesions and protein changes indicate abnormalities of the cytoskeleton, its relationship with the myelin sheath, and myosin Va molecular motor. The consequence appears to be abnormal axonal transport and inability to maintain the integrity of axons and their myelin sheaths.     

Impact of a catastrophic hurricane on island populations

Lizard and spider populations were censused immediately before and after Hurricane Lili on islands differentially affected by the storm surge. The results support three general propositions. First, the larger organisms, lizards, are more resistant to the immediate impact of moderate disturbance, whereas the more prolific spiders recover faster. Second, extinction risk is related to population size when disturbance is moderate but not when it is catastrophic. Third, after catastrophic disturbance, the recovery rate among different types of organisms is related to dispersal ability. The absence of the poorer dispersers, lizards, from many suitable islands is probably the result of long-lasting effects of catastrophes.     

Self-oriented regular arrays of carbon nanotubes and their field emission properties

The synthesis of massive arrays of monodispersed carbon nanotubes that are self-oriented on patterned porous silicon and plain silicon substrates is reported. The approach involves chemical vapor deposition, catalytic particle size control by substrate design, nanotube positioning by patterning, and nanotube self-assembly for orientation. The mechanisms of nanotube growth and self-orientation are elucidated. The well-ordered nanotubes can be used as electron field emission arrays. Scaling up of the synthesis process should be entirely compatible with the existing semiconductor processes, and should allow the development of nanotube devices integrated into silicon technology.     

Lack of acute toxicity of an anthraquinone bird repellent to non-target crayfish (Procambarus clarkii) associated with rice-crayfish crop rotations

Aeroz™ (9,10-anthraquinone (AQ)), a chemical rice seed treatment that effectively deters birds from depredating newly planted fields, could be an important management tool that enables rice producers to plant earlier in the season and increase yields. This bird repellent, while non-lethal to birds, has unknown toxicity to crayfish that often are closely integrated with rice production in southern regions of the USA. This study was conducted to assess if AQ, the active ingredient in Aeroz™, could be acutely toxic to the red swamp crayfish Procambarus clarkii (Girard), the crayfish species most often associated with rice cultivation, via seed ingestion and/or through their contact with chemical in pond water. Mortality data from a 96 h feeding study indicate that AQ-treated (1.76% by wt) rice seed was not acutely toxic to juvenile (∼3 mo.) crayfish through the ingestion exposure route. In addition, a 96 h aquatic acute toxicity test showed that the LC₅₀ of AQ in juvenile crayfish is >85 μg L⁻¹ and above the water solubility limit of AQ. These results indicate that very minimal, if any, acute toxicity would be observed in juvenile crayfish if exposed to AQ via ingestion or dissolved or suspended in the water column.     

Computer applications. An overview

Applications are programs that are designed for specific tasks. They may be written by the ultimate user or by commercial programmers. Personally written software offers the benefit of a custom solution and adaptability to changing conditions but at a very high cost. Vendor software is cheaper, but more general in nature. It may be difficult for some practitioners to find commercial software that exactly duplicates their operation, and adaptations will add expense. Software maintenance may not be available or it may mean additional cost. Veterinarians can profit from practice management packages, computer-aided diagnostics, educational software, and other programs. Computers must solve the users' problems or they are worthless. With appropriate applications, they represent one of the most cost-effective instruments in the practice.     

ULTRASOUND-GUIDED FINE-NEEDLE ASPIRATION

A simple and inexpensive modification of the ultrasound-guided fine-needle aspiration biopsy technique using an extension tube attached to the needle is described. One operator can easily manipulate the ultrasound transducer and biopsy needle while monitoring the entire procedure. This simple modification was found to facilitate ultrasound-guided fine-needle aspiration.     

Tuning High-Tc Superconductors via Multistage Intercalation

Multistage intercalation has been used to tune the interaction between adjacent blocks of CuO(2) sheets in the bigh-T(c) (high superconducting transition temperature) superconductor Bi(2)Sr(2)CaCu(2)Ox. As revealed by atomic-resolution transmission electron microscopy images, foreign iodine atoms are intercalated into every nth BiO bilayer of the host crystal, resulting in structures of stoichiometry IBi2nSr2nCanCu2nOx with stage index n up to 4. An expansion of 3.6 angstroms for each intercalated BiO bilayer decouples the CuO(2) sheets in adjacent blocks. A comparison of the superconducting transition temperatures of the pristine host material and intercalated compounds of different stages suggests that the coupling between each pair of adjacent blocks contributes approximately 5 K to T(c) in Bi(2)Sr(2)CaCu(2)Ox.     

Acute arthritis in caprine arthritis-encephalitis virus challenge exposure of vaccinated or persistently infected goats

Goats vaccinated with inactivated caprine arthritis-encephalitis virus (CAEV) developed more severe arthritis after infectious CAEV challenge exposure than did goats vaccinated with tissue culture medium. Arthritis also developed more rapidly in the group vaccinated with inactivated virus. In another experiment, goats with persistent CAEV infection developed acute arthritis after at least 2 injections of infectious CAEV at monthly intervals. In this experiment, the control group consisted of goats with persistent CAEV that were given tissue culture medium. Seemingly, the immune response to CAEV is an important cause of the CAEV-induced arthritis.