Reproductive toxicity of ergot alkaloids in mink

Ergot alkaloids are-synthesized by fungi of the Claviceps family that infect rye as well as other cereals and grains. Since a portion of the ranch mink diet is cereal, mink are at a risk of being exposed to ergot alkaloids. This study was performed to determine the reproductive toxicity of ergot alkaloids derived from ergot-contaminated oats in mink. Four groups of 12 female mink each were fed diets containing 0, 3, 6 or 12 ppm ergot alkaloids from 2w prior to the breeding season until the kits were approximately 33-d old (133 d). Females were mated with untreated males. Ergo talkaloids caused a transient decrease in feed consumption, but body weights were unaffected. The gestation period of the mink in the 6 ppm group was longer compared to controls. The number of mink whelping varied significantly with 9 mink whelping each in the control and 3 ppm groups compared to 4 mink in the 6 ppm group and 1 in the 12 ppm group. Ergot alkaloids had a significant effect on kit survivabilitywith no kits surviving in the 12 ppm group. Serum prolactin was significantly depressed in the 3 ergot alkaloid groups compared to the control group. This study indicated that ingestion of ergot alkaloids at 3 ppm or higher resulted in reproductive toxicity in mink.

Modulation of ovarian function in female dogs immunized with bovine luteinizing hormone receptor

Adult female dogs were immunized with 0.5 mg bovine luteinizing hormone receptor (LH-R) encapsulated in a silastic subdermal implant and subsequently with four intramuscular booster injections of 0.1 mg LH-R each. Circulating LH-R antibody was detected in the sera 3 weeks post-implant. The appearance of LH-R antibody was associated with a decline in the serum progesterone concentrations to a range of 0-0.5 ng/ml until day 365 in the immunized dogs in comparison with a range of 5-10 ng in the control animals, suggesting a lack of ovulation and corpus luteum function in immunized dogs. The immunized dogs did not show signs of 'standing heat' and failed to ovulate when induced by LH-RH challenge. Serum oestradiol levels, however, remained in the range of 30-40 pg/ml in both the immunized and the control dogs. With the decline in the antibody titres, the hormonal profile and vaginal cytology returned to a fertile state and the dogs exhibited signs of 'standing heat', as well as vaginal bleeding. Dogs immunized with LH-R did not show any serious metabolic, local or systemic adverse effects. The hypothalamic--pituitary gonadal axis remained intact as indicated by little difference in pituitary LH levels between control and immunized animals, and by the release of LH by LH-RH challenge. These studies demonstrate that active immunization of female dogs with LH-R could immunomodulate ovarian function to cause a reversible state of infertility. It may be postulated that, due to extensive interspecies homology, a recombinant LH receptor-based immunocontraceptive vaccine may also be effective in other vertebrates.

Use of the urine cortisol-to-creatinine ratio for monitoring dogs with pituitary-dependent hyperadrenocorticism during induction treatment with mitotane (o,p'-DDD)

OBJECTIVE

To determine whether the urine cortisol-to-creatinine ratio (UCCR) could replace the ACTH stimulation test in monitoring effectiveness of mitotane induction treatment in dogs with pituitary-dependent hyperadrenocorticism (PDH).

ANIMALS

15 dogs with PDH.

PROCEDURE

All 15 dogs were given an induction dose of mitotane (o,p'-DDD: 35 to 50 mg/kg of body weight/d) for 3 to 14 days. During the induction period, free-catch morning urine samples were collected for determination of UCCR, followed by ACTH stimulation testing, every other day. Treatment response was divided into 3 categories: well-controlled PDH (post-ACTH serum cortisol concentration > or = 28 nmol/L but < or = 138 nmol/L), deficient cortisol secretion (post-ACTH serum cortisol concentration < 28 nmol/L), and excess cortisol secretion (post-ACTH serum cortisol concentration > 138 nmol/L).

RESULTS

The linear relation between UCCR and post-ACTH serum cortisol concentration was significant (P < 0.001); however, the prediction intervals surrounding the line were too broad to be clinically useful. The UCCR overlapped among the 3 categories of treatment response. Nevertheless, dogs with PDH receiving mitotane induction treatment and with UCCR > 79 x 10(-6) were always classified as having excess cortisol secretion.

CONCLUSION AND CLINICAL RELEVANCE

The UCCR failed to predict post-ACTH cortisol concentration during mitotane induction treatment sufficiently close to be a clinically reliable indicator of treatment control. Seemingly, however, UCCR > 79 x 10(-6) obtained from a dog with PDH during mitotane induction would indicate inadequate adrenal cortex destruction and the need for continued mitotane induction; UCCR < or = 79 x 10(-6) would be inconclusive.

Use of pregnancy-specific protein-B and estrone sulfate for determination of pregnancy on Day 49 in fallow deer ()

The objective of this study was to determine if pregnancy specific protein-B (PSPB) and estrone sulfate (E(1)SO(4)) could be used to determine pregnancy status in fallow deer (Dama dama ). Forty mature does were synchronized for estrus with an intravaginal progesterone-releasing device (CIDR) and then artificially inseminated via laparoscopy with frozen semen on one day. Ultrasound examination and jugular blood sampling were done 49 days later. Transrectal ultrasonography was done to presumptively determine the pregnancy status at the time of blood sampling. Serum estrone sulfate concentrations were significantly (P < 0.05) greater in pregnant (n=31) than nonpregnant (n=9) females at 49 days of gestation (166.7 +/- 25.9 pg/ml vs 36.3 +/- 11.1 pg/ml, respectively). The percentage of [(125)I]PSPB bound was significantly (P < 0.01) lower when sera of pregnant (n=29) versus nonpregnant (n=9) females was added to RIA tubes (63.7 +/- 1.6% vs 98.1 +/- 1.6%, respectively). There were 30 fawns born from the group of females that were diagnosed pregnant based on ultrasound. We conclude that estrone sulfate and PSPB can be used to determine pregnancy status in fallow deer at 49 days of gestation.

Insulin induced fetal hypoglycaemia and fetal and maternal plasma prostaglandin concentrations in sheep in late gestation

Fetal hypoglycaemia consequent on food withdrawal for 48 h in sheep in late pregnancy is accompanied by an increase in fetal PGE2 plasma concentrations and myometrial contractility. To assess the contribution of fetal hypoglycaemia and related cellular glucopenia in the increased production of fetal PGE2 we studied the effect of 48 h insulin infusion to the fetus. Fetal whole blood glucose was lowered from 19 +/- 2 to 9 +/- 1 mg.dl-1. This experimental regimen maintains glucose availability to those fetal cells in which insulin increases glucose uptake. Fetal umbilical venous and femoral arterial PGE2 concentrations and umbilical veno-arterial PGE2 difference were unchanged, but maternal uterine veno-arterial difference for PGFM increased during the insulin induced fetal hypoglycaemia. Myometrial activity was also unchanged. We conclude that the increased fetal PGE concentration previously reported during food withdrawal is due to a deficiency of glucose to specific insulin dependent cells within vascular beds served by the fetal cardiovascular system. In addition, the findings suggest a need for a supply of glucose of fetal origin for cells that are responsible for increased PGFM concentrations in the maternal uteroplacental circulation.

A component analysis of functional communication training across three topographies of severe behavior problems

We evaluated the separate treatment components of a functional communication training program for 3 severely handicapped persons who each displayed different topographies of aberrant behavior. Following a functional analysis of maintaining conditions for inappropriate behavior (self-injury, stereotypy, aggression), each participant was trained to emit a communicative response that functioned to solicit reinforcement. For 2 participants, consequences (time-out or graduated guidance) for inappropriate behavior were also included. Treatment continued until the participants emitted the communicative response independently and no occurrences of inappropriate behavior were observed for at least two sessions. Following treatment, the separate contributions of the treatment components for communicative responding and for inappropriate behavior were evaluated with a reversal design. The results indicated that both sets of treatment components were necessary for maximal control over aberrant behavior. These results are discussed in relation to the efficiency, history, and control over reinforcement of both appropriate and inappropriate responses.