A viable foal obtained by equine somatic cell nuclear transfer using oocytes recovered from immature follicles of live mares.

The presence of heterogenous mitochondria from the host ooplast affects the acceptance of offspring obtained by somatic cell nuclear transfer. This might be avoided by obtaining oocytes from selected females, but is then complicated by low numbers of available oocytes. We examined the efficiency of equine somatic cell nuclear transfer using oocytes recovered by transvaginal aspiration of immature follicles from 11 mares. Use of metaphase I oocytes as cytoplasts and of scriptaid (a histone deacetylase inhibitor) treatment during oocyte activation were evaluated to determine if these approaches would increase blastocyst production. In experiment 1, blastocyst development was 0/14 for metaphase I oocytes and 4/103 (4%) for metaphase II oocytes. Three blastocysts were transferred to recipient mares, resulting in two pregnancies and one live foal, which died shortly after birth. In experiment 2, blastocyst development was 2/47 (4%) for control oocytes and 1/83 (1%) for scriptaid-treated oocytes. No foals were born from two blastocysts transferred in the control group. The blastocyst from the scriptaid treatment resulted in birth of a live foal. In conclusion, this is apparently the first report of production of a viable cloned foal from oocytes collected from immature follicles of live mares, supporting the possibility of cloning using oocytes from selected mares.

Evaluation of foal production following intracytoplasmic sperm injection and blastocyst culture of oocytes from ovaries collected immediately before euthanasia or after death of mares under field conditions.

OBJECTIVE: To evaluate the efficiency of foal production following intracytoplasmic sperm injection (ICSI) and blastocyst culture of oocytes from mares that died or were euthanized under field conditions. DESIGN: Prospective case series. ANIMALS: 16 mares (age, 3 to 19 years) that died or were euthanized for various causes. PROCEDURES: Ovaries were collected immediately before euthanasia (n = 10) or after death (6). Ovaries were transported to the laboratory for oocyte recovery (15 mares), or oocytes were recovered at a remote location and shipped to the laboratory (1). Oocytes underwent ICSI, and presumptive zygotes were cultured for 7 to 10 days. Blastocysts were shipped to embryo transfer facilities for transcervical transfer to recipient mares. RESULTS: Ovaries were processed 30 minutes to 12 hours (mean ± SD, 4.6 ± 3.3 hours) after mares' deaths. A mean of 14.1 ± 8.6 oocytes/mare were cultured, and 110 of 225 (49%) matured. Twenty-one blastocysts developed after ICSI and were transferred to recipient mares. Thirteen pregnancies were established; 10 healthy foals were produced from 6 donor mares. The number of blastocysts produced per mare and number of live foals produced per mare were significantly correlated with the number of oocytes recovered. CONCLUSIONS AND CLINICAL RELEVANCE: Foals were produced from mares after death or euthanasia under field conditions. Proportions of foals born overall (10 foals/16 mares) and mares from which ≥ 1 foal was produced (6/16) were greater than those reported following recovery and oviductal transfer of oocytes to inseminated recipients after death of donor mares under field conditions.

Phase I and pharmacokinetic study of 3'-C-ethynylcytidine (TAS-106), an inhibitor of RNA polymerase I, II and III,in patients with advanced solid malignancies.

BACKGROUND: TAS-106 is a novel nucleoside analog that inhibits RNA polymerases I, II and II and has demonstrated robust antitumor activity in a wide range of models of human cancer in preclinical studies. This study was performed to principally evaluate the feasibility of administering TAS-106 as a bolus intravenous (IV) infusion every 3 weeks. PATIENTS AND METHODS: Patients with advanced solid malignancies were treated with escalating doses of TAS-106 as a single bolus IV infusion every 3 weeks. Plasma and urine sampling were performed during the first course to characterize the pharmacokinetic profile of TAS-106 and assess pharmacodynamic relationships. RESULTS: Thirty patients were treated with 66 courses of TAS-106 at eight dose levels ranging from 0.67-9.46 mg/m(2). A cumulative sensory peripheral neuropathy was the principal dose-limiting toxicity (DLT) of TAS-106 at the 6.31 mg/m(2) dose level, which was determined to be the maximum tolerated dose (MTD). Other mild-moderate drug-related toxicities include asthenia, anorexia, nausea, vomiting, myelosuppression, and dermatologic effects. Major objective antitumor responses were not observed. The pharmacokinetics of TAS-106 were dose-proportional. The terminal elimination half-life (t(1/2)) averaged 11.3 ± 3.3 h. Approximately 71% of TAS-106 was excreted in the urine as unchanged drug. Pharmacodynamic relationships were observed between neuropathy and: C(5min;) AUC(0-inf;) and dermatologic toxicity. CONCLUSIONS: The recommended phase II dose of TAS-106 is 4.21 mg/m(2). However, due to a cumulative drug-related peripheral sensory neuropathy that proved to be dose-limiting, further evaluation of this bolus every 21 day infusion schedule will not be pursued and instead, an alternate dosing schedule of TAS-106 administered as a continuous 24-hour infusion will be explored to decrease C(max) in efforts to minimize peripheral neuropathy and maximize antitumor activity.