CLINICAL USE OF 99mTC-MDP SCINTIGRAPHY IN THE EQUINE MANDIBLE AND MAXILLA

^99mTc-methylene diphosphonate (MDP) radionuclide imaging examinations were done in four horses having clinical evidence of skull trauma or infection. Radiographs were made of each horse prior to scintigraphy. Four case histories are presented. In each instance, scintigraphy provided complementary information to that obtainable through radiography, which aided in accurately localizing and characterizing the site and extent of abnormalities, and which proved particularly valuable as an aid for therapeutic planning.     

Insect resistance to insecticides

The past 40 years have seen insect resistance to insecticides develop from a scientific curiosity to an immense practical problem that threatens man's ability to control not only the insect pests of agriculture but also the insect vectors that transmit major human and animal diseases. The spread of genes for cross and multiple resistance among insect pests has rendered most of our present insecticides obsolescent and very few novel insecticides are under development as substitutes. The most feasible strategy to maintain adequate control of insect pests is integrated pest management or I P M, in which insecticide management is a useful component. However, much of our present planning for the future of insect control is carried out in ignorance of past failures. We must learn from the past if we are to retain the use of chemical insecticides as a viable component of IPM.     

The process of antagonism of Sclerotium cepivorum in white rot affected onion roots by Trichoderma koningii

Trichoderma koningii (strain Tr5) grew in the epidermal mucilage of onion roots without entering healthy epidermal tissue. When placed on the epidermis of Sclerotium cepivorum -infected roots, T. koningii colonized epidermal passage cells, with little colonization of other epidermal tissues, then branched and spread throughout the root cortical tissues damaged by enzymes and toxins which diffused ahead of S. cepivorum hyphae, and impeded the path of the infection. When T. koningii colonized infected tissue, many S. cepivorum hyphae became detached at septa, cell walls dissolved and many hyphal apices burst. Contact between hyphae was not necessary for lysis to occur. T. koningii produced two endochitinases ( R _f 0·15 and 0·24) and two exo-acting chitinolytic enzymes ( R _f 0·46 and 0·62) during degradation of crabshell chitin and S. cepivorum cell walls. The R f 0·24 and 0·46 proteins were detected when T. koningii colonized S. cepivorum -infected roots and are likely to be a component of the antagonism process.     

Sperm Morphology in the Domestic Cat, and its Relation with Fertility: A Retrospective Study

Knowledge about normal ranges in semen quality and the association between sperm morphology and fertility in felids is limited. The aims of this retrospective study were to (1) define a normal spermiogram in cats; (2) evaluate possible effects of season, age and breed on sperm morphology; and (3) evaluate the relationship between sperm morphology and fertility. Semen samples collected by electroejaculation from 52 cats were evaluated for sperm morphology. The cats constituted two groups: a general population of cats (n = 48) and cats examined because of poor breeding records (n = 4). The general population was divided into household (n = 20), pedigree (n = 19) and colony cats (n = 9) and into three age classes, <12 months, 12-59 months and >or=60 months. The median percentage of normal spermatozoa in the general population was 44.0% (range 1.0-91.0%). Criteria were tentatively set for what was considered a normal spermiogram. The mean percentage of normal spermatozoa was higher during February to July than during August to January (p < 0.05). Pedigree cats had a lower mean percentage of normal spermatozoa than did household cats (p < 0.05). Age had no effect on the percentage of normal spermatozoa but was positively correlated with the percentage of proximal droplets. Of the cats with <40% normal spermatozoa (n = 19), all those with known breeding records (n = 11) had produced litters. The four cats examined because of poor breeding results had higher percentages of different sperm abnormalities than tentatively stipulated for the normal spermiogram. In two of these cats both sperm morphology and fertility changed over time.