Transitional Cell Carcinoma of the Urinary Bladder in a Beluga Whale (Delphinapterus leucas)

A transitional cell carcinoma of the urinary bladder was found in a beluga whale stranded in the St. Lawrence middle estuary. Various organs of this animal were submitted to high resolution gas chromatography coupled with mass spectrometry analysis. High frequency of urinary bladder cancer in the human population of the same area and the presence of carcinogenic compounds in the marine environment of this animal are discussed.

Concurrent isolation of Edwardsiella tarda from various organs of this whale is also reported.

     

A model to study the effect of certification of planting material on the occurrence of leek rust

Based on a simple model, the possible effects of certification of planting material on the occurrence of leek rust in a region can be derived from information on the proportion of infected fields (v) and the proportion of newly planted fields with infected planting material (i) in that region. Ifv i, certification of planting material will be highly effective.     

Detection of the K99 antigen of Escherichia coli in calf faeces by enzyme-linked immunosorbent assay (ELISA)

Summary An enzyme-linked immunosorbent assay (ELISA) is presented for the detection of the K99 antigen of Escherichia coli in calf faeces. False-positive reactions were not observed with K99-negative strains and with several viral antigens. Only bovine coronavirus caused slight positive reactions which could be eliminated by a blocking test. As compared with the conventional procedure for the detection of the K99 antigen, ELISA seemed to be at least as sensitive and had the advantage that samples could be stored at -20° C before testing. In addition many samples could be handled at the same time and the results became available quickly. By carrying out the assay as a blocking test, specific antibody against K99 in serum or colostrum could be detected and titrated.     

Blood parasites of sheep in the Netherlands. I. Anaplasma mesaeterum sp.n. (Rickettsiales, Anaplasmataceae)

Summary On two occasions an anaplasm was isolated from sheep on the Dutch island of Ameland. The organism proved to be highly pathogenic for splenectomised sheep; a non-splenectomised animal recovered spontaneously after the packed cell volume had decreased by 40%. Treatment with oxytetracycline was effective. Its pathogenicity for goats appeared to be low, and the organism was apparently not infective to splenectomised cattle. This anaplasm differs from Anaplasma ovis in that less than 30% of the organisms are marginally situated in the red cell, as against over 70% in A. ovis; cross-immunity with A. ovis was incomplete and the latter appeared to be far more pathogenic to goats than the Dutch anaplasm, for which the name Anaplasma mesaeterum sp.n. is proposed. Its ultrastructure is similar to that of A. marginale and A. ovis. The vector is either Ixodes ricinus or Haemaphysalis punctata. Its practical importance remains to be ascertained.     

Prevalence of antibodies to equine viruses in the Netherlands

Summary The prevalence of antibodies to various viruses was investigated in a series of serum samples collected from horses in the Netherlands between 1963 and 1966 and from 1972 onwards. Neutralizing antibodies to equine rhinopneumonitis virus, equine arteritis virus and to equine rhinovirus types 1 and 2 were detected in respectively 76%, 14%, 66% and 59% of the equine serum samples tested. The observed incidence of serum samples positive to equine adenovirus in the complement fixation test was 39%. Precipitating antibodies to equine infectious anaemia virus were detected only in serum samples from two horses imported from abroad. Haemagglutination inhibiting antibodies to Myxovirus influenzae A / equi-1, M. Influenzae A / equi-2, and Reovirus types 1, 2, and 3 were present in respectively 82%, 50%, 10%, 33% and 3.6% of the serum samples tested. The most frequently observed incidence of antibodies to the various equine respiratory viruses occurred in the groups of horses having repeatedly contact with other horses.     

Host parasite relationships in Trypanosoma (duttonella) vivax with special reference to the influence of antigenic variation

A mouse model system was used to study various aspects of host and parasite relationships in Trypanosoma vivax infections. These included the phenomenon of antigenic variation, the variable parasite antigens responsible for this phenomenon, parasite-host adaption, host immune responses and the role of genes in the major histocompatibility complex in the control of infection. While the mouse model system has allowed investigation of these aspects of host parasite relationships, it is clear that the system is much more limited than those generally used in T. brucei spp and T. congolense infections. This is indicated by the discovery that not all VATs of T. vivax were equally infective for mice, though in some cases infectivity could be improved by bovine serum supplementation and/or immunosuppression of the mouse host. In the case of rats, infection was even restricted to a smaller number of the VATs studied. It was, however, possible to biochemically characterize the variable surface antigen carried by T. vivax and show its similarity to those carried by T. brucei and T. congolense. The H-2 complex was found not to influence acquired resistance of inbred strains. Cyclic transmissions of T. vivax infections to goats combined with chemotherapy were carried out in an attempt to induce protection to subsequent infection as has been shown in T. brucei and T. congolense infections. Such protection could, however, not be obtained, The failure of the metacyclic VATs to induce immunity, was perhaps due to rapid decrease in antibody titres to bloodstream VATs found after treatment and prior to rechallenge. The usefulness of the mouse model system in elucidating the mechanisms responsible for the non-H-2 linked differences in susceptibility to T. vivax infections should be further explored and its relevance to mechanisms of trypanotolerance in domestic ruminants defined.     

The effect of Prussian blue and sodium-ethylenediaminetetraacetic acid on the faecal and urinary elimination of thallium by the dog.

After oral administration of sublethal doses of thallium (lower than 10 mg/kg) to dogs, 75.5 +/- 3.9 per cent of the dose was eliminated from the body--47 per cent faecal and 28 per cent urinary. Cumulative excretion reached 50 and 70 per cent after 10 and 25 days respectively, and was almost complete after 75 days. This was slightly lower at higher doses. The total body-burden of thallium, calculated from the cumulative excretion, decreased exponentially for at least the first 40 days with a half-time (T 1/2) of 6.5 days. Oral doses of Prussian blue after 10 days resulted in an acceleration of the thallium elimination from the body (T 1/2 2.5 days), an increase of the faecal (49 per cent) and a decrease of the urinary excretion (18 per cent). Nevertheless, the cumulative faecal and urinary thallium excretion was not influenced. Minor transitory influences of Prussian blue on the faecal thallium excretion could be observed up to day 26. After 40 days, Prussian blue could no longer influence the faecal thallium excretion. At no time did sodium-ethylenediaminetetraacetic (Na2EDTA) acid significantly change faecal or urinary thallium excretion.     

Inhibition of chitin synthesis by two 1-(2,6-disubstituted benzoyl)-3-phenylurea insecticides. II

The knowledge of the biochemical mode of action of 1-(4-chlorophenyl)-3-(2,6-difluorobenzoyl)urea (diflubenzuron) is presented, explaining the insecticidal effect. Like its structural analog, 1-(2,6-dichlorobenzyl)-3-(3,4-dichlorophenyl)urea (Du 19111), it inhibits chitin synthesis in the cuticle of larvae. Virtually complete inhibition was demonstrable 15 min after the application of diflubenzuron. Neither diflubenzuron nor Du 19111 has any effect upon chitinase activity either in vivo or in vitro. The insecticidal effect upon the cuticle, therefore, must be explained as an inhibition of chitin synthesis and not as an activation of chitin degradation. In contrast to the action of Du 19111, no accumulation of N-acetylglucosamine occurs upon treatment of larvae with diflubenzuron. Similarities and differences in the mode of action of both compounds are discussed, together with other effects reported in the literature.     

Laparoscopic surgery in adult cattle.

Laparoscopy in cattle is a promising tool for clinical diagnosis and treatment. The lower cost of the materials available in addition to the possibility of an intervention on an animal that is sedated does not entail more costs than an exploratory laparotomy. The application of this tool during abdominal explorations and biopsies allows the avoidance of invasive and often useless surgical interventions and even with the diagnosis and prognosis of certain conditions. Surgical techniques currently are limited to abomasopexies; however, never-ceasing progress and improvements in human surgery are expected to affect the future of bovine surgery.With the advancements in the multimedia technology used by universities, the use of laparoscopy as a pedagogic tool definitely has a promising future. Endoscopic exploration of the thorax is possible using the same material as for laparoscopy. In addition, diagnostic and biopsy applications are useful. The use of the laparoscope in different body cavities and for different applications would make the purchase of the required materials more cost-effective.     

Prepenetration stages in infection of clematis by Phoma clematidina

A detailed study of conidial germination, germ-tube growth and the formation of infection structures in Phoma clematidina , the causal agent of clematis wilt, is described for two clematis varieties differing in disease resistance. On both the resistant and susceptible varieties, the fungus entered leaves and stems by direct penetration of the cuticle, often, but not always, following the formation of infection structures. More germ tubes per conidium were formed on the susceptible host, but these germ tubes were on average shorter than on the resistant host. Although germ tubes regularly entered the plant via trichomes, stomata were not found to be sites of entry. Following penetration of the cuticle of resistant plants, germ-tube growth was sometimes restricted to the subcuticular region, and halo formation occurred at the sites where penetration was attempted. Subcuticular growth and halo formation were not observed on susceptible plants. These observations may partly explain the resistance of small-flowered clematis varieties to P. clematidina .