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B L Dresser

Publications and source records attributed to B L Dresser.

18 recordsLinked to original sources
PubMed2006

In vitro production and transfer of cat embryos in the 21st century.

Appreciable progress has been made in the development of assisted reproductive technology (ART) for creating in vitro embryos in cats. Moreover, the extent of advancement in the last decade has been similar, albeit of more modest magnitude, to that seen in some other domestic and laboratory species, particularly when the disparities in financial, and, hence, scientific, resources are considered. The recent progress in domestic felid ART has made it possible to envisage their potential role in supporting the conservation of endangered felid species, which, in reality, is a multifarious process requiring wide-ranging, yet coordinated approaches. The prospect of incorporating ART into that intricate domain, with limited exceptions, remains a long-term, but highly motivating objective. Meanwhile, the straightforward accessibility and abundant supply of domestic cat gametes from local veterinary clinics provides a valuable and practical source of material for further research on the basic aspects of in vitro oocyte maturation, fertilization and early embryo development. Furthermore, extrapolating the domestic biotechniques to non-domestic felids has produced encouraging results in some species.

Animals↗
PubMed2006

Nuclear transfer in cats and its application.

Nuclear transfer (NT) technology is typically used for generating identical individuals, but it is also a powerful resource for understanding the cellular and molecular aspects of nuclear reprogramming. Most recently, the procedure has been used in humans for producing patient-specific embryonic stem cells. The successful application of NT in cats was demonstrated by the birth of domestic and non-domestic cloned kittens at a similar level of efficiency to that reported for other mammalian species. In cats, it has been demonstrated that either in vivo or in vitro matured oocytes can be used as donor cytoplasts. The length of in vitro oocyte maturation affects in vitro development of reconstructed embryos, and oocytes matured in vitro for shorter periods of time are the preferred source of donor cytoplasts. For NT, cat somatic cells can be synchronized into the G0/G1 phase of the cell cycle by using different methods of cell synchronization without affecting the frequency of in vitro development of cloned embryos. Also, embryo development to the blastocyst stage in vitro is not influenced by cell type, but the effect of cell type on the percentage of normal offspring produced requires evaluation. Inter-species NT has potential application for preserving endangered felids, as live offspring of male and female African wildcats (AWC, Felis silvestris lybica) have been born and pregnancies have been produced after transferring black-footed cat (Felis nigripes) cloned embryos into domestic cat (Felis silvestris catus) recipients. Also, successful in vitro embryo development to the blastocyst stage has been achieved after inter-generic NT of somatic cells of non-domestic felids into domestic cat oocytes, but no viable progeny have been obtained. Thus, while cat cytoplasm induces early nuclear remodeling of cell nuclei from a different genus, the high incidence of early embryo developmental arrest may be caused by abnormal nuclear reprogramming. Fetal resorption and abortions were frequently observed at various stages of pregnancy after transfer of AWC cloned embryos into domestic cat recipients. Abnormalities, such as abdominal organ exteriorization and respiratory failure and septicemia were the main causes of death in neonatal cloned kittens. Nonetheless, several live domestic and AWC cloned kittens have been born that are seemingly normal and healthy. It is important to continue evaluating these animals throughout their lives and to examine their capability for natural reproduction.

Animals↗
PubMed2006

In vitro embryo production and embryo transfer in domestic and non-domestic cats.

Over a 5-year interval, multiple laparoscopic oocyte retrievals were done in fishing cats (Prionailurus viverrinus), caracals (Caracal caracal) and domestic cats after ovarian stimulation with gonadotropins. From 21 retrievals in five fishing cats, 579 preovulatory oocytes (mean = 27.6) were recovered and 348 embryos were produced in vitro (mean = 16.6). A total of 452 preovulatory oocytes (mean = 25.1) were recovered from 18 of 24 retrievals in six caracals and 297 (mean = 16.6) embryos were produced. An additional 16 caracal embryos (19%) were produced after in vitro maturation of 83 oocytes, 59 of which came from six retrievals producing only immature oocytes. The presence of corpora lutea at oocyte retrieval occurred in each species (1) at a similar frequency (33%) and (2) more frequently during January through May (11 of 15 retrievals) than during the latter half of the year (4 of 30 retrievals). Of the 12 embryo transfer procedures done in fishing cats, one pregnancy (8%) was obtained and one live kitten born after the auto-transfer of 10 Day-6 embryos. In caracals, a total of 46 Day-4 or Day-5 embryos were auto-transferred to six recipients, one of which delivered two live kittens. Then, 109 caracal embryos were cryopreserved before thawing and transferring to nine recipients (mean = 12.1) on Days 5 or 6. From three pregnancies established (33%), a total of three kittens were born. Two to six gonadotropin treatments/oocyte retrievals were done in domestic cats during 1999 through 2003; an average of 24.9, 23.5, 22.0, 23.1, 23.5 and 40.9 oocytes (P > 0.05) were recovered at the first through the sixth treatment cycles from 138, 138, 97, 49, 22, and seven retrievals, respectively.

Animals↗
PubMed2003

Development of in-vitro-derived bovine embryos in protein-free media: effects of amino acids, glucose, pyruvate, lactate, phosphate and osmotic pressure.

In experiment 1, the effects of a group of either 20 (i.e. glutamine + essential + non-essential) or 11 (i.e. hamster embryo culture medium (HECM)-6) amino acids were evaluated in modified potassium simplex optimised medium (mKSOM) or basic medium (BM)-3. In experiment 2, the effects of glucose, pyruvate, lactate, phosphate or all four substrates were evaluated in low- or high-osmotic pressure BM-3 (255 and 275 mOsmol respectively) containing 20 amino acids (BM-3-20aa). In experiment 1, mKSOM containing 20 amino acids (mKSOM-20aa) supported the highest frequency of total, expanded (Days 7, 8 and 9) and hatched blastocysts. In experiment 2, supplement type affected the frequency of development to at least the morula stage (Day 7), expanded (Day 8), hatched (Day 9) or total blastocysts and cell number per blastocyst. Osmotic pressure affected the frequency of expanded blastocysts (Day 7) and blastocyst cell number. Regardless of the osmotic pressure, BM-3-20aa containing glucose (0.2 mM) supported the highest frequency of blastocyst development. The interaction between supplement type and osmotic pressure was not significant; however, treatment mean differences were more marked in high- than in low-osmotic pressure medium. In conclusion, the beneficial effects of amino acids on in vitro embryo development are influenced by the base medium. Moreover, glucose-containing media supported a higher frequency of embryonic development than pyruvate- and/or phosphate-supplemented media, indicating that glucose plays more important roles in non-energy generating pathways.

Amino Acids↗
PubMed2000

Births of kittens produced by intracytoplasmic sperm injection of domestic cat oocytes matured in vitro.

In Experiment 1, cleavage frequency and in vitro development of domestic cat embryos produced after in vitro maturation of oocytes obtained from ovaries after ovariohysterectomy (in vitro) with that of oocytes retrieved from follicle-stimulating hormone-treated donors at 24 h after administration of luteinizing hormone (in vivo) and fertilization by intracytoplasmic sperm injection (ICSI) or IVF were compared. In each group presumptive zygotes were assessed for cleavage on IVC Days 1 and 4 and for development to blastocysts on IVC Day 7. In vitro matured oocytes had lower frequencies of meiotic maturation (59.2% v. 66.5%), cleavage at Day 1 (41.4% v. 64.9%) and development to the morula stage at Day 4 (65.8% v. 87.9%) than did in vivo matured oocytes, after ICSI and IVF. Development to the blastocyst stage was lower in in vitro matured oocytes (19.0%) than in vivo matured oocytes (29.5%) after ICSI. In Experiment 2, we evaluated the capacity of sperm injected oocytes without a visible polar body to undergo cleavage and in vitro development. More in vivo matured than in vitro matured oocytes underwent cleavage at Day 1 (46.6% v. 12.6%) and developed to the morula stage by Day 4 (66.7% v. 46.1%), but no blastocysts were obtained at Day 7 in either group. In Experiment 3, we evaluated the in vivo viability of domestic cat embryos derived from ICSI of in vitro matured oocytes. Morula stage embryos were transferred to 18 domestic cat recipients either on Day 4 or 5 after oocyte recovery. A total of 3 domestic cat recipients were pregnant after transfer to recipients on Day 5. Two pregnant cats delivered two normal and healthy live male kittens on Day 68 of gestation and the remaining cat delivered a male kitten on Day 62 that died during the last two days of gestation. These results demonstrate that: (1) inadequate cytoplasmic maturation of in vitro matured domestic cat oocytes is the main cause of deficient oocyte activation; (2) the injection of oocytes without a visible polar body is a useful technique to evaluate oocyte cytoplasmic maturation; and (3) blastocysts obtained after ICSI of in vitro matured oocytes are viable and not a result of parthenogenesis.

Animals↗
PubMed1998

Development of embryos produced by intracytoplasmic sperm injection of cat oocytes.

Development of cat oocytes following intracytoplasmic sperm injection (ICSI) and in vitro fertilization (IVF) was compared in two experiments. Domestic cat donors (used as a model for wild felids) were treated with 150 IU equine chorionic gonadotrophin (eCG) on treatment day 1 or a total of 10-15 IU of follicle-stimulating hormone (FSH) over four days, followed by 100 IU human chorionic gonadotrophin (hCG) on day 5 and follicular aspiration 24-26 h later. A jaguarundi (Herpailurus yaguarondi) female was stimulated twice with FSH (20 IU) or eCG (300 IU) and hCG (250 or 300 IU) before oocyte recovery. After storage at 4 degrees C, domestic cat semen was washed and processed. For ICSI, denuded oocytes were each injected with an immobilised spermatozoon. IVF oocytes were co-incubated with 5 x 10(4) motile spermatozoa/0.5 ml for 4-6 h. Noncleaving oocytes were fixed and stained 24-28 h after injection or insemination. Presumptive zygotes were cultured before transfer on day 5 (experiment I only) or evaluation on day 7 (experiments I and II). In experiment I, fertilization frequency was 67.9% (72/106) and 58.1% (122/210) for IVF and ICSI oocytes, respectively (P > 0.05). Most noncleaving ICSI oocytes (71/88, 80.7%) at 24 h were at metaphase II, of which half (35/71, 49.3%) had an activated spermatozoon (n=4) or premature chromatin condensation (PCC, n=31) of the sperm head. All 69 day 7 IVF embryos developed to morulae (> 16-cells, 46.7%) or blastocysts (53.3%), and 59/63 (93.7%) ICSI embryos reached the morula (50.8%) or blastocyst (42.9%, P > 0.05) stage. Mean cell number in IVF and ICSI embryos was 136 and 116 (P > 0.05); morulae had 77 and 46 (P < 0.05) and blastocysts had 187 and 209 (P > 0.05) cells, respectively. After transfer of 10 or 11 day 5 ICSI morulae to each of four recipients, a total of three kittens were born to two dams at 66 or 67 days. Of 18 fair-to-good quality oocytes recovered from a jaguarundi on two occasions, 10 (55.6%) embryos were produced by ICSI with fresh (n=5) or frozen (n=5) conspecific spermatozoa, but no jaguarundi kittens were born after transfer of these embryos to domestic cat recipients. In experiment II, cleavage frequency following IVF (15/17, 88.2%) and ICSI (31/38, 81.6%) was higher (P < 0.05) than following sham ICSI (13/35, 37.1%). Mean cell number (27 cells) and blastocyst development (0%) on day 7 was lower (P < 0.05) in the sham ICSI group than in the ICSI group (45 cells, 15.6% blastocysts) which, in turn, was lower (P < 0.05) than the IVF group (94 cells, 46.7% blastocysts). We have demonstrated that ICSI can be applied successfully in domestic felids and suggest that the technique will effectively augment other biotechniques being developed for enhancing reproduction in endangered felids.

Animals↗
PubMed1997

Birth of a western lowland gorilla (Gorilla gorilla gorilla) following in vitro fertilization and embryo transfer.

A 21-year-old multiparous female exhibiting 31-41 day menstrual cycles was given hFSH (225 IU/day, Metrodin 75, from cycle day 3 through 9 (menses = day 1) and hCG (10,000 IU, Profasi, on day 10 to stimulate follicular development. At 35 h after hCG, under isoflurane (AErrane) anesthesia, follicles were aspirated by controlled suction under transvaginal ultrasound guidance. Metaphase II oocytes (n = 11) were placed in modified human tubal fluid (mHTF, 100 microliters) medium under oil at 37 degrees C in humidified 5% CO2. Frozen semen, collected by voluntary ejaculation, was thawed (70 degrees C H2O bath, 6 sec), diluted slowly, centrifuged, and resuspended in mHTF, and 160,000 motile spermatozoa/ml were added at 6 h after oocyte recovery. At 21 h postinsemination (p.i.) eight oocytes were at the two-cell stage, five were cryopreserved, and three were cultured to the six- to eight-cell stage in mHTF with granulosa cells before transcervical uterine transfer at 47 h p.i. using a Teflon catheter. Micronized progesterone (400 mg/d) was orally administered for 10 weeks posttransfer (p.t.). Ultrasound examination revealed a single fetus at 15 weeks p.t., and unassisted delivery of a live 1.37 kg female infant occurred at 29 weeks. Am. J. Primatol. 41:247-260, 1997.

Animals↗
PubMed1997

In vitro and in vivo development of embryos produced by in vitro maturation and in vitro fertilization of cat oocytes.

Cumulus-oocyte complexes of domestic cats were classified by morphology of ooplasm (A = good, B = fair, C = poor) and cultured for 24 h in TCM 199 with gonadotrophins (eCG, FSH, hCG or FSH/hCG). More of type A oocytes (52%) underwent in vitro maturation (IVM) than of type B (41%) or type C (17%). The gonadotrophin source did not affect frequency of IVM of type A (50-53%) or type B (38-44%) oocytes, but IVM of type C oocytes in hCG or FSH/hCG (27%/19%) was about double that in eCG or FSH alone (13%/10%). After IVF, frequency of cleavage for type A (54%), B (41%) and C (26%) oocytes was similar to the IVM frequency of the equivalent type. After 7 days, development to the morula (M) stage in vitro was similar among types (47-58%); however, higher percentages of type A and B oocytes developed to blastocysts (Bl), 31% and 29%, respectively, than of type C (15%). After transfer of day 5 (n = 70) or 6 (n = 32) M and Bl to day 4 or 5 recipients in trial 1 (n = 4) and 2 (n = 3), respectively, the three recipients in trial 2 gave birth to four live kittens. Development in vitro to M of IVM/IVF embryos frozen in propanediol plus sucrose during early cleavage was similar (64-69%) to that of cohort controls (64%), but Bl formation was reduced (13-17% versus 32%). Damage to the zona pellucida after plunging into liquid nitrogen at -30 degrees C was higher (11%) than that of the embryos cooled at 10 degrees C min-1 from -30 degrees C to -150 degrees C before storage (2%).

Animals↗
PubMed1994

Successful in vitro and in vivo development of in vitro fertilized two- to four-cell cat embryos following cryopreservation, culture and transfer.

In vitro and in vivo survival of in vitro-derived 2- to 4-cell cat embryos following cryopreservation was examined. Prefreeze 1- vs 2-step cryoprotectant exposure (Experiment 1) and warming method (Experiment 2) on zona pellucida damage and development in vitro were compared. To determine viability in vivo, frozen/thawed embryos were cultured in vitro to the morula/early blastocyst stage and transferred to synchronous recipients (Experiment 3). At 24 to 26 h after IVF, embryos were cryopreserved in 1.4 M propanediol (Pr)+0.125 M sucrose (Su) by cooling at 0.3 degrees C/min from -6 degrees C to -30 degrees C and storing in liquid nitrogen. Autologous embryos were cultured in vitro for 7 d. After warming for 5 sec in air and 10 sec at 37 degrees C in water (Experiments 1 to 3), or at room temperature air (22 degrees C; Experiment 2), the cryoprotectant was removed and embryos were cultured in vitro for 6 d (Experiments 1 and 2). Development was assessed after staining by counting cell numbers/embryo and determining the percentages at the 2- to 4-cell (nonsurvivor), pre (5 to 15), early (16 to 32), mid (33 to 50), late (>50) morula or blastocyst stages. Post-thaw development to late morula/blastocyst after 1-step exposure (68%, 15 min Pr+Su) was higher (P<0.05) than that after 2-step exposure (36%, 15 min Pr and 15 min Pr+Su). Both warming methods produced similar percentages of embryos with damaged zonae (13 to 15%) and equivalent development to morula/blastocyst (64 to 69%). Development in vitro to early morula/blastocyst of frozen embryos with intact zonae was similar to that of nonfrozen embryos. Following cryopreservation, most 2- to 4-cell cat embryos retained their capability for in vitro development to morula/blastocyst, and in vivo viability was demonstrated by the birth of 3 live kittens to 2 of 4 recipients following the transfer of 58 embryos.

Journal Article↗
PubMed1993

In vitro fertilization in domestic and non-domestic cats including sequences of early nuclear events, development in vitro, cryopreservation and successful intra- and interspecies embryo transfer.

The domestic cat may be used as a model for developing assisted reproduction techniques including in vitro fertilization (IVF), embryo culture, cryopreservation and embryo transfer (ET) for application to threatened and endangered species of non-domestic cats. Interoestrous domestic cats were injected with a total of 1.0-6.0 mg follicle-stimulating hormone (FSH) daily for 4 days and with 100 iu human chorionic gonadotrophin (hCG) on day 5. Follicular oocytes recovered at 26 +/- 1 h after hCG were co-incubated for 4-6 h at 38 degrees C in 5% CO2 with spermatozoa (1-2 x 10(5) motile spermatozoa ml-1) collected by artificial vagina. To determine the timing of sperm penetration and early fertilization events in vitro, oocytes were fixed and examined at intervals from 0.5 to 10 h after sperm exposure. The penetration rate of metaphase II (MII) oocytes at 0.5-3 h was equivalent to that at 3-6 h (95 versus 96%). Second polar body extrusion, pronuclear formation and apposition were observed at 2, 6-8 and 10 h, respectively. Simple (Tyrode's) and complex (F-10, M-199 and CMRL-1066) culture media with 10% fetal calf serum were compared for their ability to support development to the morula or blastocyst stage during culture periods of 96-168 h after IVF. The average number of cells per embryo was similar (P > 0.05) in the various media at each interval except that CMRL-1066 reduced (P < 0.05) development at 96 h if it was used before the two-cell stage. In F-10, neither the presence of intact cumulus cells nor changing to fresh F-10 medium at 48 h affected development at 96 h. Blastocyst development at 168 h was similar in both F-10 (18%) and Tyrode's (26%). To determine developmental ability in vivo, IVF-derived embryos (n = 586) were transferred at 96 or 120 h to recipients (n = 49) that had undergone synchronous oocyte recovery as donors. The percentage of recipients producing kittens after transfer of embryos cultured for 96 or 120 h in F-10 was 31 and 25, respectively, compared with 55% of 120 h recipients receiving embryos cultured in M-199 or Tyrode's. Overall, more pregnancies occurred following transfer of > or = 12 embryos (11/26) than if < 12 embryos were transferred (6/23).(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1988

First successful transfer of cryopreserved feline (Felis catus) embryos resulting in live offspring.

Sexually mature domestic cats were hormonally stimulated to induce superovulation; embryo recovery was accomplished by laparotomy. Embryos were frozen by conventional embryo freezing methods used in the domestic cattle embryo transfer industry. Thawing was achieved in a 28 degrees C or 37 degrees C waterbath or in ambient air. Overnight culture of the frozen-thawed embryos in a supplemented Nutrient Mixture F-10 (Ham's) or Earle's Balanced Salt Solution with 20% heat-treated newborn calf serum resulted in five successful term litters from recipient queens. Embryo recipients who became pregnant had been treated with a subcutaneous injection of follicle-stimulating hormone (FSH-P) once every 24 hr for 6 days in the amount of 0.2 mg/day for the first 5 days and 0.1 mg on the sixth day, followed by two intramuscular 750 IU injections of human chorionic gonadotropin 24 hr apart, beginning on the same day as the sixth injection of FSH-P.

Animals↗
PubMed1988

Veno-occlusive disease of the liver in captive cheetah.

Liver tissues from 126 captive cheetah were evaluated by light microscopy and histochemistry; eight animals were evaluated by electron microscopy. The main hepatic lesion, a vascular lesion resembling veno-occlusive disease (VOD) of the liver and characterized by subendothelial fibrosis and proliferation of smooth muscle-like cells in the central veins, was seen in 60% of the sexually mature cheetah. Although this hepatic vascular lesion was seen in cheetah as young as 1 year of age, the most severe lesions, usually associated with liver failure, were found in cheetah between the ages of 6 and 11. There was no sex predisposition, and in approximately 40% of the VOD cases, liver disease was not suspected clinically or at necropsy. VOD was found in other felidae, especially in the snow leopard. High levels of vitamin A in livers, as well as in diets of the cheetah, could be a contributing factor in the development of VOD in some groups of cheetah.

Acinonyx↗
PubMed1987

Dietary estrogens--a probable cause of infertility and liver disease in captive cheetahs.

The cheetah in the wild is "racing towards extinction" mostly due to habitat destruction. Its survival will probably depend on accelerated captive breeding. At this time, however, reproductive failure and liver disease threaten the future of the captive cheetah population. Histopathological evaluation of more than 100 cheetah livers identified venocclusive disease as the main hepatic lesion responsible for liver disease in this species. Analysis of the commercial feline diet by high-performance liquid chromatography and gas-liquid chromatography-mass spectrometry revealed large amounts of two phytoestrogens identified as daidzein and genistein. These compounds were found to be derived from a soybean product that was a component of the cheetah diet, and their concentrations both ranged from 18 to 35 micrograms/g diet. The adult cheetah consequently consumes approximately 50 mg/day of these weak estrogens. When extracts of the diet were tested for estrogenicity using a bioassay, a dose-related increase in uterine weight was observed. In 4 cheetahs studied, withdrawal of this feline diet by substitution with a chicken diet resulted in an improvement in conventional liver function tests and a normalization in the appearance of hepatic mitochondria. We conclude that the relatively high concentrations of phytoestrogens from soybean protein present in the commercial diet fed to captive cheetahs in North American zoos may be one of the major factors in the decline of fertility and in the etiology of liver disease in this species. The survival of the captive cheetah population could depend upon a simple change of diet by excluding exogenous estrogen.

Acinonyx↗
PubMed1981

Effect of prostaglandin E2 on cervical compliance in pregnant ewes.

Cervical compliance increases dramatically at parturition in sheep independent of uterine activity. Recently, in vitro production of prostaglandin E2 (PGE2) by the cervix has been shown to increase at parturition. This study investigated the effects of PGE2 on cervical compliance and uterine blood flow in pregnant ewes. Eight animals were chronically instrumented with pressure balloons within the cervical os and amniotic cavity, an electromagnetic flow probe on a uterine artery, and catheters in the maternal cervical os, femoral artery, femoral, uterine, and cervical veins, and fetal hindlimb vein. PGE2 (10 mg) was administered in a water-soluble gel into the cervical os every 4 hours times three doses at least 5 days after surgical preparation (124 to 142 days' gestation). In all eight ewes, cervical compliance increased within 8 to 12 posttreatment hours to levels comparable to that seen at spontaneous parturition. Five of the ewes did not progress into labor; compliance in these ewes returned to baseline 24 to 72 hours after the peak. Uterine blood flow was measured in five ewes during the PGE2 treatment and demonstrated no significant alterations. Maternal cardiovascular and fetal respiratory parameters were monitored throughout the experiment and remained stable. The present data suggest that PGE2 may be an important regulatory of the biochemical and physical changes which occur in the cervix at parturition.

Animals↗
PubMedDate not supplied

Stimulation of ejaculated domestic cat sperm motility with caffeine, pentoxifylline, and 2'-deoxyadenosine.

Sperm motility patterns of cryopreserved domestic cat ejaculates treated at 37 degrees C with 1 mM caffeine, pentoxifylline, or 2'-deoxyadenosine were analyzed using computer-assisted semen analysis (CASA). The percent motility (MOT), curvilinear velocity (VLC), straight-line velocity (VSL), linearity (LIN), and amplitude of lateral head displacement (ALH) were measured for each group following 15 min of treatment. Motility indices were examined during a 6-h treatment period to determine the effect of each chemical on sperm longevity. Caffeine, pentoxifylline, and 2'-deoxyadenosine each increased (p > .05) the MOT and VCL of the ejaculates compared to the controls. The longevity of the treated and control samples were not significantly different throughout the incubation period. These results, similar to previous findings with cryopreserved epididymal cat sperm, demonstrate that motility stimulants can significantly elevate the MOT and VCL of cryopreserved ejaculated cat sperm without having deleterious effects on longevity.

Animals↗