Scrapie I. Transmission and Pathogenesis

Homogenized brain, extracts, and residues of brain from normal and scrapie sheep were inoculated into 116 sheep. Of 72 sheep inoculated with scrapie material 27 developed the disease, whereas four of 44 inoculated with `normal' brain material showed symptoms similar to those of scrapie. The scrapie agent survived extraction for 18 hours with diethyl ether followed by water for 24 hours. Similarly the agent survived extraction in a Soxhlet apparatus with 95 per cent ethanol containing 2.0 per cent 4 M HC1 for 24 hours.

There was no evidence of demyelination in sections of brain and spinal cord supporting the view that allergic encephalomyelitis is not responsible for the scrapie symptoms. Liver function, as measured by the bromsulfalein test, remained normal until just before death. These results preclude that liver dysfunction contributes to the disease but do not exclude the possibilities of other metabolic derangements.

     

Sex determination of bovine embryos using H-Y antibodies

6 days old bovine embryos (n = 126) were obtained from 8 superovulated cows or heifers by flushing the uteri and oviducts either non-surgically or after slaughter. Part of the embryos (n = 72) (morula stages) were placed in Ham's F-10 or PBS supplemented with 10% fetal calf serum (FCS) diluted 1:1 with supernatant from the H-Y antibody producing clone and cultured at 38 degrees C, in 5% CO2/95% air and 100% humidity. Control embryos (n = 54) were cultured in H-Y antibody free medium. After culture the embryos could be separated into a blastocyst--and a morula group. A subsequent colchemid and hypotonic treatment and fixation and Giemsa staining allowed a precise karyotyping, and thus sex determination for 36 H-Y antibody treated embryos and 22 control embryos. The limiting factor for proper karyotyping was lack of metaphases, incomplete methaphases or poor preparation. Among the H-Y antibody treated embryos we found 7 males and 15 females in the blastocyst and 14 males and 0 females in the morula group. A statistical analysis of these proportions led to the conclusion that the H-Y antibody had a significant influence on the sex ratio.     

Intestinal choristoma in the midcervical region of a dog

A 5-year-old, neutered male, mixed-breed dog was evaluated for a fluctuant mass in the right midcervical region. The mass recurred following aspiration of its contents and after removal of the right sublingual and mandibular salivary glands. The lateral midcervical location of the mass and the serous nature of the fluid within the mass were inconsistent with a salivary mucocele. Excisional biopsy was curative and revealed an intestinal choristoma.     

Vitrification with DAP 213 and Cryotop of Ex Situ and In Situ Feline Cumulus–Oocyte Complexes

This study was undertaken to compare cryotolerance, in terms of viability and resumption of meiosis after warming and culture (24 and 48 h), of ex situ (isolated) and in situ (enclosed in the ovarian tissue) feline cumulus–oocyte complexes (COCs) vitrified with DAP 213 (2 m DMSO, 1 m acetamide, 3 m propylene glycol) in cryotubes or Cryotop method. Ovaries were harvested from 49 pubertal queens. Of each pair of ovaries, one was dissected to release COCs randomly divided into three groups: fresh COCs (control), ex situ COCs vitrified with DAP 213 and Cryotop. The cortex of the other ovary was sectioned into small fragments (approximately 1.5 mm³) and randomly assigned to be vitrified by DAP 213 or Cryotop. After warming, ex situ and in situ (retrieved form vitrified ovarian tissue) COCs were matured in vitro. Viability of oocytes was highly preserved after warming and culture in all treatments. Proportions of oocytes surrounded by complete layers of viable cumulus cells were remarkably decreased (p < 0.00001) in both vitrification procedures compared to fresh oocytes. Resumption of meiosis occurred in all treatments. After 24 h of culture, results were similar in ex situ and in situ vitrified oocytes regardless of the vitrification protocol used (range 29–40%), albeit lower (p < 0.05) than those of fresh oocytes (65.8%). After 48 h of culture, ex situ oocytes vitrified with Cryotop achieved the rates of meiosis resumption similar to fresh oocytes (53.8% vs 67.5%; p > 0.05) and ex situ and in situ oocytes vitrified with DAP 213 showed similar rates of resumption of meiosis. These findings demonstrated that DAP 213 and Cryotop preserve the viability of ex situ and in situ oocytes, but cumulus cells are highly susceptible to vitrification. However, the capability to resume meiosis evidences that feline immature oocytes vitrified as isolated or enclosed in the ovarian cortex have comparable cryotolerance.     

Trypanocidal Activity of Marine Natural Products

Marine natural products are a diverse, unique collection of compounds with immense therapeutic potential. This has resulted in these molecules being evaluated for a number of different disease indications including the neglected protozoan diseases, human African trypanosomiasis and Chagas disease, for which very few drugs are currently available. This article will review the marine natural products for which activity against the kinetoplastid parasites; Trypanosoma brucei brucei, T.b. rhodesiense and T. cruzi has been reported. As it is important to know the selectivity of a compound when evaluating its trypanocidal activity, this article will only cover molecules which have simultaneously been tested for cytotoxicity against a mammalian cell line. Compounds have been grouped according to their chemical structure and representative examples from each class were selected for detailed discussion.