Teratological examination of the insecticide methylparathion (Wofatox 50 EC) on pheasant embryos. 1. Morphological study

Teratogenic effects of methylparathion / Wofatox 50 EC/ and Parathion 20 WP as positive control material were tested in pheasant embryos. On the 12th day of incubation 0.1 ml of the emulsions or suspensions of the insecticides at different concentrations was inoculated into the air space of embryonated eggs. The following dose levels were employed: 27 and 270 mg/kg egg of Wofatox 50 EC, and 10 mg/kg of Parathion 20 WP. Morphological changes were evaluated by macroscopic, skeletal staining and light microscopic examinations of the embryos. Primary hypoplasia or atrophy developed in the cervical musculature /m. longus colli/ accompanied by lordosis and scoliosis of the cervical spine. In most cases we also found cyllosis .     

Dexamethasone and prednisolone in the horse: pharmacokinetics and action on the adrenal gland

Pharmacokinetics of dexamethasone and prednisolone were studied in 6 horses given dexamethasone alcohol (IV or IM) or dexamethasone 21-isonicotinate as a solution IV or IM (50 micrograms/kg of body weight), prednisolone 21-sodium succinate IV or IM (0.6 mg/kg of body weight), or prednisolone acetate IM (0.6 mg/kg of body weight). Plasma concentrations were determined using a high-performance liquid chromatographic method. After dexamethasone alcohol (IV) or dexamethasone 21-isonicotinate (IV), the half-life of elimination was similar (53 minutes) for both formulations. After dexamethasone (alcohol and isonicotinate, IM), concentrations were low or nondetected. After prednisolone 21-sodium succinate (IV), the half-life of elimination (99.5 minutes) was significantly (P less than 0.01) longer than that for dexamethasone. After prednisolone 21-sodium succinate (IM), absorption was rapid and bioavailability was high. After prednisolone acetate (IM), absorption was slow and prednisolone was present in plasma for about 7 days. Due to the nonlinearity of prednisolone kinetics, a bioavailability higher than 100% was obtained. The basal plasma hydrocortisone concentration was approximately 70 ng/ml. After dexamethasone (IV or IM), plasma hydrocortisone values decreased after a 2-hour delay and returned to base line after a 3 to 4 day delay. After prednisolone 21-sodium succinate (IV or IM), plasma hydrocortisone decreased immediately (IV) or rapidly (IM) and returned to base line after a 24-hour delay. After prednisolone acetate (IM), plasma hydrocortisone decreased for up to 21 days.     

Analysis of chicken embryonic development after removal of blastodermal cells for sexing

1. The present study evaluated developmental characteristics in the chick embryo throughout incubation following cell removal from the freshly laid egg. 2. Between 10 and a few hundred cells of the blastoderm were removed for sex diagnosis. Incubation of the treated embryos was then continued in an open egg shell culture system. 3. Cell recovery from different regions within the blastoderm was performed. 4. The experiments presented here demonstrate the persistence of the developmental potential of chicken embryos in an in ovo culture system after removal of different numbers of cells from the germinal disc prior to incubation. 5. No deviations in developmental characteristics were recorded when compared to untreated control cultures. 6. No detrimental effects of double cell biopsies could be observed. 7. A similar number of chicks developed to hatch regardless of the location of manipulation within the blastoderm.     

Modified lateral spinal decompression in 61 dogs with thoracolurnbar disc protrusion

A modified lateral spinal decompression technique was performed in 61 dogs with thoracolumbar disc protrusion. Myelography combined with plain radiography and neurological examination determined the side of greatest compression in 93 per cent of the dogs. Disc material was retrieved in 98 per cent of the cases. Of the 35 non-ambulatory dogs, 95 per cent regained the ability to walk. The recovery time was three weeks.     

Results of Craniotomy for the Treatment of Cerebral Meningioma in 42 Cats

Forty-two cats underwent craniotomy for removal of a meningioma between 1985 and 1991. Median duration of clinical signs before examination was 1.25 months. All cats had inappropriate demeanor: 48% were dull and 38% were lethargic. Neurological deficits included impaired vision in 93%, paresis in 83%, and seizures in 19%. Computed tomography (CT) showed solitary masses in 86% and multiple masses in 14%. Intraoperative complications included hemorrhage and difficulty excising deep or adherent masses. Anemia in 13 of 42 cats was the most common immediate postoperative complication. Ten of 42 cats had no improvement or a more severe neurological status after surgery. Eight of 42 cats died immediately after surgery; 6 of these were anemic. Of the cats that survived the immediate postoperative period, evaluation 10 to 14 days after surgery showed that 97% (33 of 34) were alert and 79% (27 of 34) had returned to normal behavior. Neurological deficits, except for vision impairment, had resolved in most cats. The duration of follow-up varied from 1.3 months to 55.1 months. Ten cats developed neurological abnormalities from 1 month to 44.2 months after surgery; of these, 6 had tumor recurrence or new growth confirmed by CT scan or necropsy. Overall survival was 71% at 6 months, 66% at 1 year, and 50% at 2 years. Age of cat and location of tumor did not significantly affect survival ( P = . 1034 and .1851, respectively). There were too few precise measurements of tumor size to make a valid statistical comparison of the effect of size on survival. Location or presence of multiple tumors did not affect final outcome. Results of this study indicate that surgical excision is a beneficial method of treatment of cranial meningioma in cats.