Gelatinous Mass Research Articles

The cryptogenic bait worm Diopatra biscayensis Fauchald et al., 2012 (Annelida: Onuphidae) – Revisiting its history, biology and ecology

The polychaetous annelid Diopatra biscayensis Fauchald et al., 2012 was recently described from the Atlantic coast of France. It has been the subject of a plethora of publications dealing with its importance in the field of ecology: from its role as an ecosystem engineer, being an indicative species of climate change in western Europe to questions of whether it was native or introduced to the old continent, spawning theories about its hypothetical routes of introduction and spreading. We have redescribed D. biscayensis, traced its biogeographical history in the Bay of Biscay through examination of old museum holdings and studied its ecology and reproductive biology throughout a one year period from a northern Spain estuary, showing for the first time that the species is a protandric simultaneous hermaphrodite. The annual spawning season is from early August to late September, when large numbers of oocytes of 260 μm diameter were deposited in gelatinous egg masses attached to the parental tubes. Early trochophores developed in the jelly mass by 4–6 h, 3-chaetiger metatrochophores after 48 h, and the jelly mass had totally disintegrated by 72 h, releasing the lecithotrophic larvae. Our studies have clarified the morphology and reproductive pattern of D. biscayensis, documented that the species has inhabited the European waters for more than a century and we hope that these findings will serve as a basis to robust ecological studies and hypotheses concerning this and the related species.

Estimating fecundity in the zygoparous species Helicolenus dactylopterus (Actinopterygii, Scorpaeniformes): adaptation of the gravimetric method

Bluemouth, Helicolenus dactylopterus is zygoparous species with internal fertilization spawning multiple batches of early-celled embryos in gelatinous masses. Its unusual reproductive strategy required methodological adjustments to estimate potential annual fecundity. The present study applied an adaptation of the gravimetric method, estimated batch fecundity based on different spawning fraction criteria (gestation, early-celled, and blastula females), and compared these estimates with the number of developing oocytes (NDOR) in the beginning of spawning to clarify the oocyte development pattern. Spawning fraction estimation based on the gestation criterion was considered the most reliable given its low variance and the subjectivity of staging early-celled embryos. On average, 87 batches were spawned with a mean spawning interval estimated at 1.73 days, and a mean relative annual total fecundity of 1,773 embryos g−1 carcass. The inexistence of a clear decreasing trend in the NDOR throughout the spawning season, and the lower NDOR estimates in females in the beginning of spawning comparing with relative annual fecundity (gestation criterion) suggests vitellogenic oocyte recruitment supporting previous results of indeterminate fecundity in Portuguese coast. The method proposed can be considered in fecundity studies of other commercial important species which extrudes gelatinous egg masses.

Diagnostic Challenge

An adult female Northern red-bellied cooter (Pseudemys rubriventris) was presented with a 15-day history of anorexia and lethargy. On physical examination, the animal was considered to be in critical condition with a prominent swelling of the proximal aspect of the left forelimb. Laboratory analysis highlighted anemia, hyperuricemia, hyperuremia, low total protein, and elevated aspartate aminotransferase and lactate dehydrogenase. Radiographic images revealed a soft tissue mass infiltrating the humerus with boney involvement. Fine-needle aspiration was performed, and cytological evaluation indicated the sample was characterized by a prevalence of spindle to stellate cells frequently containing intracytoplasmatic brown to black granules associated with a moderate amount of mucin. The terrapin died 24 hours later with only the affected forelimb being submitted for histopathological evaluation. On gross examination, the proximal humerus was encircled by a 3-cm diameter, black, gelatinous mass with a mucoid, black appearance on cut surface. The histologic description of the mass was that it was a poorly demarcated, sparsely cellular, nonencapsulated neoplasm expanding from the dermis and infiltrating into the underlying soft tissues and bone. The neoplasm was composed of stellate cells embedded in an abundant periodic acid-Schiff–positive myxoid stroma. The cells frequently contained intracytoplasmic brown-black granules. These findings are consistent with a mucinous type of melanophoroma. Melanophoromas are tumors of melanin-producing cells and are well known in reptiles, most commonly in snakes and bearded dragons (Pogona vitticeps) but rarely reported in chelonians. The mucinous variant has only been described in the bearded dragon.

Aggressive angiomyxoma of the vulva: a bizarre perineal lesion.

Introduction. Aggressive angiomyxoma is a rare, slowly growing, and benign tumour of mesenchymal origin, which affects women of reproductive age and is associated with a high risk of local recurrence. Case Presentation. A case of a 47-year-old white female is presented herein, with a large polypoid, gelatinous mass on the right labia majora, measuring 26 × 21 × 6 cm. Histopathologically, the lesion was composed of spindle and stellate-shaped cells embedded in a myxoid matrix. Another specific feature was the presence of variable-sized thin-walled capillaries and thick-walled vascular channels. The patient underwent wide local excision of the tumour with clear margins and developed local recurrence 18 months later. Discussion. Aggressive angiomyxoma of the vulva needs to be distinguished from benign myxoid tumors with a low risk of local recurrence as well as from malignant myxoid neoplasms. Usually wide local excision with tumour-free margins and occasionally hormonal manipulation is the treatment of choice.

Mucinous Melanophoroma in a Northern Red-Bellied Cooter (Pseudemys rubriventris)

An adult female Northern red-bellied cooter (Pseudemys rubriventris) was presented with a 15-day history of anorexia and lethargy. On physical examination, the animal was considered to be in critical condition with a prominent swelling of the proximal aspect of the left forelimb. Laboratory analysis highlighted anemia, hyperuricemia, hyperuremia, low total protein, and elevated aspartate aminotransferase and lactate dehydrogenase. Radiographic images revealed a soft tissue mass infiltrating the humerus with boney involvement. Fine-needle aspiration was performed, and cytological evaluation indicated the sample was characterized by a prevalence of spindle to stellate cells frequently containing intracytoplasmatic brown to black granules associated with a moderate amount of mucin. The terrapin died 24 hours later with only the affected forelimb being submitted for histopathological evaluation. On gross examination, the proximal humerus was encircled by a 3-cm diameter, black, gelatinous mass with a mucoid, black appearance on cut surface. The histologic description of the mass was that it was a poorly demarcated, sparsely cellular, nonencapsulated neoplasm expanding from the dermis and infiltrating into the underlying soft tissues and bone. The neoplasm was composed of stellate cells embedded in an abundant periodic acid-Schiff–positive myxoid stroma. The cells frequently contained intracytoplasmic brown-black granules. These findings are consistent with a mucinous type of melanophoroma. Melanophoromas are tumors of melanin-producing cells and are well known in reptiles, most commonly in snakes and bearded dragons (Pogona vitticeps) but rarely reported in chelonians. The mucinous variant has only been described in the bearded dragon.

Egg Cannibalism inPomacea canaliculata(Caenogastropoda: Ampullariidae) from the Southern Pampas: An Alternative Trophic Strategy?

Pomacea canaliculata is a freshwater gastropod native to southern South America and is listed among the world's 100 worst invaders. Diverse food sources can be exploited by this apple snail, including snails with gelatinous and subaquatic egg masses. Records of ingestion of their own egg masses (egg cannibalism), which are aerial and calcareous, have only been anecdotal in P. canaliculata. Our aims were to study egg cannibalism in a natural population and also under laboratory conditions. In a stream population from the southern Pampas, we recorded P. canaliculata attacking their own fresh egg masses, which had been naturally submerged by an increase in water level. In addition, when we artificially submerged fresh and old egg masses in a field experiment, we observed several snails readily attacking both. In the laboratory, we also observed the capture by pedal surface collecting of floating remains of egg masses. In laboratory trials, juveniles fed on eggs reached larger sizes than starved snails but smaller than those fed on lettuce; adult snails also eat eggs, but their growth rates were not affected by the food regime. Pomacea canaliculata eggs present defensive and anti-nutritive compounds that apparently dissuade almost all potential predators, but this snail did not appear to be negatively affected when feeds on its own eggs. The ingestion of egg remains and submerged egg masses is probably more frequent than previously considered in P. canaliculata, which may take advantage of using these alternative food resources when others are scarce.

STUDY OF CHEMISTRY OF FORMATION OF BARIUM AZIDE

This article proposes a chemism of the barium azide formation through monoazidometilat barium. The results obtained allowed to eliminate possible stops of the process due to formation of gelatinous mass by varying duration of the process.

Proteomic analysis of human vitreous humor.

BackgroundThe vitreous humor is a transparent, gelatinous mass whose main constituent is water. It plays an important role in providing metabolic nutrient requirements of the lens, coordinating eye growth and providing support to the retina. It is in close proximity to the retina and reflects many of the changes occurring in this tissue. The biochemical changes occurring in the vitreous could provide a better understanding about the pathophysiological processes that occur in vitreoretinopathy. In this study, we investigated the proteome of normal human vitreous humor using high resolution Fourier transform mass spectrometry.ResultsThe vitreous humor was subjected to multiple fractionation techniques followed by LC-MS/MS analysis. We identified 1,205 proteins, 682 of which have not been described previously in the vitreous humor. Most proteins were localized to the extracellular space (24%), cytoplasm (20%) or plasma membrane (14%). Classification based on molecular function showed that 27% had catalytic activity, 10% structural activity, 10% binding activity, 4% cell and 4% transporter activity. Categorization for biological processes showed 28% participate in metabolism, 20% in cell communication and 13% in cell growth. The data have been deposited to the ProteomeXchange with identifier PXD000957.ConclusionThis large catalog of vitreous proteins should facilitate biomedical research into pathological conditions of the eye including diabetic retinopathy, retinal detachment and cataract.

Resolving the electrospinnability zones and diameter prediction for the electrospinning of the gelatin/water/acetic acid system.

The development of suitable biomimetic scaffolds is a fundamental requirement of tissue engineering. Although electrospinning has emerged as an effective method for producing such scaffolds of nanometer-sized fibers, the influence of solution characteristics on the morphology of the resulting nanofibers depends on each polymer solution system. In this study, gelatin nanofibers and microfibers were prepared via electrospinning using mixtures of water and acetic acid at different ratios as solvents. The viscosities of gelatin solutions before electrospinning were analyzed and two different behaviors were found as a function of the solvent composition, taking into account classic models of polymer science. A power law relationship between viscosity and gelatin concentration was found for each solvent system, and an empirical model including the influence of acetic acid was obtained for aqueous systems. Moreover, a ternary diagram considering gelatin, water, and acetic acid mass fractions was constructed as a tool to establish the electrospinnability domains in terms of fiber occurrence and morphology. Also, the isodiametric curves were defined in the fibers region. Finally, in order to correlate the diameter of electrospun nanofibers and the electrospinnability zones, the Berry number was used. However, as its only allows the range of electrospinnability to be established for a fixed solvent composition, a new dimensionless parameter (Bemod) was suggested to take into account all the acetic acid aqueous solutions as a single solvent.

Life history and seasonal breeding of the deep-sea annelid Ophryotrocha sp. (Polychaeta: Dorvelleidae)

Shallow-water annelids of the genus Ophryotrocha have become a popular biological system for exploring ecological, behavioral, developmental, and toxicological questions. Here we report on the successful maintenance in holding tanks, complete life cycle, and reproductive phenology of a first deep-water representative that could be used as a model species. This Ophryotrocha, which has yet to be formally described, is large (12–16mm long) and exhibits simultaneous hermaphroditism. Specimens collected off northeast Newfoundland (eastern Canada) between 500 and 1500m depth were monitored under flow-through laboratory conditions for over three years. They consistently exhibited seasonal feeding from April to February, followed by a reproductive season between February and May. Gametogenesis was initiated in early January and completed in early to mid-February, followed by courtship, which mainly involved pairs of individuals attached head to tail for hours to days. Transparent gelatinous masses containing 80–110 eggs were laid from mid-February to late-March. Propagules developed in the mass to the 1-chaetiger stage and, at an ambient temperature of ~1–4°C, offspring emerged 30–45 days post-laying. Only ~40–45% of the eggs laid developed to the 1-chaetiger stage, with evidence of adelphophagy. After emerging from the gelatinous mass, 1-chaetiger stages remained aggregated and were guarded by adults for a few days before dispersing. All parents died following the dispersal of their offspring. The new generation reached sexual maturity in 8–9 months and was ready to reproduce the following January–February. A few cases of segmenting adult worms were also observed. Three complete generations developed successively to sexual maturity over the course of this study.

Nuptial gifts and female fecundity in the neotropical katydid Conocephalus ictus (Orthoptera: Tettigonidae)

In general, female fitness is greatly increased in gift-giving insects. In katydids, this nuptial gift consists of a gelatinous mass produced by accessory glands: the spermatophylax, which is attached to the ampulla. During mating, males of the neotropical katydid Conocephalus ictus transfer a spermatophylax that is ingested by the females. Fecundity, egg-laying rate and longevity were higher in females that consumed the spermatophylax than in those that did not. Also, female receptivity turned off after mating. Females actively rejected other males by hitting them with their forelegs and moving away. Their refractory period lasted as long as 17d. Only a few females accepted a 2nd mating and died a few days later. In C. ictus, spermatophylax consumption can be beneficial for both males and females. On one hand, the compounds in the spermatophylax or the ejaculate could prevent or delay females from copulating with rivals, thus avoiding sperm competition. On the other hand, such compounds can improve the females' opportunity to increase their lifespan and fecundity. Moreover, a rise in egg-laying rate may lower the risk of female prereproductive death caused by rapid oviposition. In any case, the boost in female egg laying might also be beneficial for males because their number of offspring increases.

Oviposition site influences dispersal potential in a marine bubble snail

For benthic marine invertebrates that deposit offspring inside protective capsules or gelatinous egg masses, small-scale variation in environmental parameters can affect offspring mortality, performance, timing of hatching and dispersal potential. Plasticity in hatching and dispersal potential have received less attention than egg mass mortality and juvenile performance, but there may be adaptive responses that balance the costs and benefits of benthic and pelagic development in specific contexts, such as escaping poor environments. Some species, such as the bubble snail Haminoea japonica, produce two offspring phenotypes at hatching that differ in dispersal potential. Here, I investigated whether the substrata that egg masses develop on can influence whether offspring tended to hatch as either phenotype. In the field, egg masses were more commonly deposited in association with filamentous algae and in laboratory experiments, free-swimming larvae settled and metamorphosed more readily on algae. When egg masses developed on the algae that induced settlement, there were more crawl-away juveniles than free-swimming larvae. Such a response has important consequences for dispersal potential, hence the deposition substratum may have an adaptive value because crawl-away juveniles can avoid a potentially risky planktonic period when settlement substratum is present, but larvae can disperse when a suitable settlement substratum is absent.

Symbiotic Association Between Symbiodinium and the Gastropod Strombus gigas: Larval Acquisition of Symbionts

The importance of the dinoflagellate Symbiodinium sp. was studied in the early life stages of the gastropod Strombus gigas. This dinoflagellate was not found in the eggs or the gelatinous mass surrounding the eggs of the mollusk; therefore, Symbiodinium is not inherited directly. To determine whether the planktonic veligers can acquire these algae from the environment, they were exposed to freshly isolated Symbiodinium from adult S. gigas (homologous). The optimal stage for Symbiodinium inoculation was found at 48h post-hatching. Survival and growth rates of veligers and juveniles were higher when inoculated with freshly isolated Symbiodinium in conjunction with daily feeding of Isochrysis spp. Veligers inoculated with Symbiodinium freshly isolated from three host species elicited distinct responses: (1) veligers did not take up Symbiodinium isolated from the hydrozoan Millepora alcicornis suggesting that there is discrimination on contact prior to ingestion, (2) veligers did take up Symbiodinium isolated from the anemone Bartholomea annulata, but the algae did not persist in the host tissue suggesting that selection against this type took place after ingestion or that the algae did not divide in the host, and (3) veligers did take up Symbiodinium isolated from Pterogorgia anceps where it persisted and was associated with metamorphosis of the larvae. In contrast, the Symbiodinium freshly isolated from S. gigas were not associated with metamorphosis and required an inducer such as the red alga Laurencia poitei. These data present a significant advancement for the establishment of a new approach in the aquaculture of this important but declining Caribbean species.

Preparation of the Edible Biocomposite Film Gelatin/Bacterial Cellulose Microcrystal (BCMC): Variation of Matrix Concentration, Filler, and Sonication Time

Several biodegradable polymers have been explored to develop biodegradable edible films in order to reduce the use of conventional plastics. In this study, edible biocomposite film is made from gelatin filled with Bacterial Cellulose Microcrystal (BCMC). BCMC is produced from nata de coco paste, which is hydrolyzed with cellulase enzyme. In making biocomposite, gelatin matrix is first dissolved in distilled water and then mixed with BCMC filler solution in ultrasonic bath. The solution resulted is then casted and dried in room temperature. The addition of BCMC is proven to improve physical properties, mechanical, and thermal properties of the resulting material. BCMC distribution of SEM showed increasing the tensile strength test results, DSC, and WVTR. When the BCMC concentration was varied from 1-4 wt% of the gelatin mass, tensile strength and glass transition temperature (Tg) increased from 37.07 MPa to 74.04 MPa and 27.520°C to 39.60°C, respectively. Water Vapour Transmission Rate (WVTR) decreased from 37.77 gr.m-2.h-1 to 19.73 gr.m-2.h-1. Tensile test and DSC results also increased when varying the sonication time from 3-6 minutes, from 48.57 MPa to 57.23 MPa and 25.890°C to 37.290°C. WVTR decreased from 36.09 gr.m-2.h-1 to 20.54 gr.m-2.h-1.

Pediatric Lipoblastoma of the Neck

Lipoblastoma is a rare, benign, and encapsulated tumor arising from embryonic white fat. Most of the cases occur in the extremities and the trunk; only a few cases in the head and the neck are reported. Thus, we present a case of lipoblastoma of the neck with a review of the literature. A 1-year-old male infant presented to our hospital, with a history of painless swelling in the left side of the neck for 3 months that was rapidly enlarged. His birth history and medical history were unremarkable. A physical examination demonstrated a soft and compressible mass in the left side of the neck. The mass was nontender to palpation and mobile without cellulitic changes in the overlying skin. A computed tomographic scan showed that the mass is heterogenous, has low attenuation in nature, and is 3.8 × 2.8 × 9 cm in size. Under general anesthesia, transverse cervical incision was made through the neck wrinkle, and there was no invasion of any of the neck structures. Complete surgical excision demonstrated yellowish-white, irregular lobules of immature fat cells separated by a loose and myxoid connective tissue. Grossly, the mass was a homogeneous tan-pink gelatinous mass. A microscopic examination demonstrated a small number of capillaries and mature fat cells, and differentiating immature lipoblastoma cells were detected in the myxoid stroma. A pathologic finding confirmed the diagnosis of lipoblastoma. The postoperative course was uneventful. The patient underwent follow-up for 1 year after the operation, and there was no evidence of recurrence. The most common presentation of lipoblastoma is a painless, rapidly enlarging neck mass. Published reports showed that most of them occur before the age of 3 years. Complete surgical excision is the treatment of choice. Although lipoblastoma is an extremely rare benign tumor, it should be considered in the diagnosis of neck mass in children younger than 3 years.

Umbilical Endometriosis

A29-year-old Hispanic woman presented with bleeding from her umbilicus. No lesions could be observed due to the bleeding, and the patient gave an obscure history of when the bleeding began and if it was associated with her menstrual periods. Other than an increased body mass index, physical examination, laboratory results and pelvic ultrasound examination were normal. She had no complaints of pelvic pain or dyspareunia. The patient returned several months later without bleeding. Examination of the umbilicus revealed a small friable gelatinous mass (Figure 1A, arrow) at the right inferior border deep within the umbilicus. Subsequent biopsy demonstrated histological evidence of stratified endometrial glands and stroma (Figure 1B, at×10 magnification).

Preparation of the Edible Biocomposite Film Gelatin/Bacterial Cellulose Microcrystal (BCMC): Variation of Matrix Concentration, Filler, and Sonication Time

Several biodegradable polymers have been explored to develop biodegradable edible films in order to reduce the use of conventional plastics. In this study, edible biocomposite film is made from gelatin filled with Bacterial Cellulose Microcrystal (BCMC). BCMC is produced from nata de coco paste, which is hydrolyzed with cellulase enzyme. In making biocomposite, gelatin matrix is first dissolved in distilled water and then mixed with BCMC filler solution in ultrasonic bath. The solution resulted is then casted and dried in room temperature. The addition of BCMC is proven to improve physical properties, mechanical, and thermal properties of the resulting material. BCMC distribution of SEM showed increasing the tensile strength test results, DSC, and WVTR. When the BCMC concentration was varied from 1-4 wt% of the gelatin mass, tensile strength and glass transition temperature (Tg) increased from 37.07 MPa to 74.04 MPa and 27.520°C to 39.60°C, respectively. Water Vapour Transmission Rate (WVTR) decreased from 37.77 gr.m-2.h-1 to 19.73 gr.m-2.h-1. Tensile test and DSC results also increased when varying the sonication time from 3-6 minutes, from 48.57 MPa to 57.23 MPa and 25.890°C to 37.290°C. WVTR decreased from 36.09 gr.m-2.h-1 to 20.54 gr.m-2.h-1.

Revealing polychaetes invasion patterns: Identification, reproduction and potential risks of the Korean ragworm, Perinereis linea (Treadwell), in the Western Mediterranean

An established population of the polychaetous annelid Perinereis linea (Treadwell) is reported for the first time outside its native distribution range (NW Pacific). This exotic worm has reached the Western Mediterranean (Mar Menor lagoon) via importing live fishing-bait as it is commonly used by anglers in Mar Menor lagoon, an area largely used for recreational fishing. To avoid confusion with other related species, and because the scientific name has been in synonymy for many years, P. linea is redescribed and illustrated. We focus on the reproductive biology and ecology of P. linea to help to understand its introduction, naturalization and spread along this coastal lagoon. Comparison between the Mediterranean population with a native population from South Korea revealed that the species exhibits a great reproductive plasticity and adaptability, which depends on the environmental conditions. Perinereis linea can reproduce after acquiring the epitokous form or prior to complete epitokal modification. In the Mar Menor lagoon population females release eggs asynchronically without completing epitokal modifications. However, under particular laboratory conditions females produce eggs synchronically and release them after complete epitokal transformations. Fertilization can occur internally in the female coelom, and females release zygotes and larvae through openings in their body walls; they are then incubated in gelatinous masses attached to the female parapodia. The sperm morphology is of the ent-aquasperm type. The eggs and larvae are attacked by symbiotic ciliate protozoa that feed on their yolk reserves. These foreign ciliates may act as carriers of disease in native beachworms and constitute an important risk for the ecosystem health. Finally, we provide recommendations on the prevention of the adverse effects that this exotic ragworm can cause in receiving ecosystems.

Microstructure characterization through mechanical, electrokinetic and spectroscopic methods of polyampholyte gelatin hydrogels crosslinked with poly(vinyl alcohol)

The microstructure of polyampholyte gelatin hydrogels crosslinked covalently with fully hydrolyzed poly(vinyl alcohol) is characterized. The experimental methodology involves simple mechanical extension, spectroscopic and thermal methods (FTIR, XRD, DSC, TGA) and equilibrium swelling test to quantify relevant microstructural parameters and electrokinetic properties of this polyampholyte-polypeptide hydrogel, for a well defined range of crosslinker to gelatin mass ratios. These polyampholyte crosslinked matrices having different positive effective electrical charge are studied within an experimental and theoretical framework of their elastic and swelling properties. Estimations of average mesh size and toughness of the swollen hydrogels are provided. The feasibility of polyion complexation between positive crosslinked gelatin chains and negative bioactive macromolecules to be delivered through hydrogel biodegradation is analyzed. Several additional hydrogel properties are estimated like shear modulus, average molecular mass of network strands, swelling ratio, Flory–Huggins interaction parameter, hydrogel electrostatic zeta-potential and average effective charge number per chain before and after the crosslinking process to quantify gelatin chain cationization.

Laparoscopic Application of PGE2 to the Uterine Tube Surface Enhances Fertility in Selected Subfertile Mares

Topical application of prostaglandin E2 (PGE2) gel to the surface of the uterine tubes via a laparoscopic procedure improved embryo recovery rates or pregnancy rates in 28 subfertile mares suspected of uterine tubal pathology. Gelatinous masses may occlude the lumen of the uterine tube and prevent sperm from reaching the site of fertilization or prevent embryos from reaching the uterus. PGE2 is secreted by the early equine embryo, promoting passage of the embryo into the uterus; topical administration of PGE2 onto the surface of the uterine tube has been shown to stimulate early transport of the embryo into the uterus. Embryos were produced or a pregnancy was obtained from 24 of the 28 barren mares treated with direct laparoscopic application of 0.2 mg of PGE2 to their uterine tubes. Mares had been barren for an average duration of 1.9 ± 0.6 years and an average of 6.9 ± 3.8 estrous cycles prior to treatment, without donating an embryo or becoming pregnant. Seventeen of 20 mares bred as embryo donors produced one or more embryos with an average of 2.1 ± 1.9 embryos collected per mare (0.45 embryos per cycle) after PGE2 treatment. Seven of 8 mares bred to carry their own pregnancy became pregnant within the first two cycles following PGE2 treatment. These 8 mares were bred an average of 5.6 ± 1.8 cycles without a pregnancy prior to treatment. The laparoscopic PGE2 procedure was performed during various stages of the estrous cycle; the stage varied among treated mares.