Microparticles in health and disease.

Microparticles (MPs), small membrane-derived vesicles, are derived from many cell types and released into the circulation. Microparticles can express antigens, and contain cell surface proteins, cytoplasmic contents, and nuclear components from their cell of origin that determines their composition, characterization, and transfer of biologic information. Certain prompts for this release include shear stress, complement activation, proapoptotic stimulation, cellular damage, or agonist interaction with cell surface receptors. Release can be physiologic or pathologic and is associated with proinflammatory and procoagulant effects and has been implicated in thrombotic states. Microparticles also contribute to systemic inflammation and cardiovascular, hematologic, and oncologic disease states. The study of MPs in human medicine is rapidly advancing and extends into the physiology of health, the pathophysiology of disease, and the role of MPs in transfusion medicine. In veterinary medicine, published work on MPs has been limited to the area of inherited disorders, blood storage, and leukoreduction (LR). Microparticle research is still in its infancy, and this review should be seen as a snapshot of what is currently known. As research continues important limitations, including variations in preanalytic variables such as collection, storage, or centrifugation, and limitations of quantitation are coming to the forefront. Correlation of quantitation of MPs with assays of activity will hopefully shed light on the true nature of MPs in health and disease. This review will focus on the role of cellular exocytic vesiculation in health, disease, and transfusion medicine.

Chorionic gonadotropin, estradiol, and progesterone levels in baboons (Papio anubis) during early pregnancy and spontaneous abortion.

The purpose of this study was to sequentially characterize peripheral chorionic gonadotropin (CG), estradiol (E2), and progesterone (P) profiles during early pregnancy in the baboon (Papio anubis). Ten pregnant baboons were bled sequentially at eighteen time points between Days 8 and 128 of gestation. In addition, blood was obtained at corresponding time points from 5 spontaneously aborting baboons. CG levels were assessed in a mouse Leydig cell bioassay using rhesus pituitary LH as the standard E2 and P levels were measured by RIA. Pregnancy-associated CG activity was detectable by Day 15 (901.4 +/- 275.6 ng/ml), peaked at Day 27 (53,494.1 +/- 14,995.6 ng/ml), and then returned to baseline values by Day 51 (45.4 +/- 8.9 ng/ml). Mean E2 concentrations rose from 28.9 +/- 4.3 pg/ml on Day 8 to 280.6 +/- 145.5 pg/ml on Day 58 and then increased 9-fold to a level of 2436.4 +/- 928.0 pg/ml on Day 72. Mean E2 concentrations ranged between 2065.9 and 3830.9 pg/ml from Day 72 through Day 128. Mean P concentrations ranged from 7.5 to 10.2 ng/ml between Days 8 and 21, rising dramatically to 38.6 +/- 4.6 ng/ml on Day 37 prior to declining to levels that ranged from 11.1 to 17.1 ng/ml between Days 51 and 128. CG levels were low in 3 of 5 animals prior to spontaneous abortion E2 and P concentrations preceding spontaneous abortion were similar to values in uncomplicated pregnancy; however, at the time abortion was detected P concentrations in all 5 animals were 1.3 ng/ml or less.(ABSTRACT TRUNCATED AT 250 WORDS)

Ultrasonic determination of fetal parameters in baboons (Papio anubis)

The use of nonhuman primates to study reproductive physiology, fetal development, and neonatal management often depends on the availability of pregnant and fetal animals of known gestational history. The purpose of this study was to establish and correlate normal fetal growth parameters with gestational age in olive baboons (Papio anubis). Normal cycling females were bred to proven males by using the degree of perineal swelling and vaginal cytology to determine onset of ovulation. The subjects were evaluated to determine pregnancy beginning 18 days postmating, using an Aloka-650 diagnostic ultrasound unit, equipped with a 7.5 mHz prostate probe and a 5 mHz transabdominal probe. Ten pregnant animals were then evaluated sonographically every 3 days through day 30 and weekly through day 135 (average gestation 184 days). Measurements included gestational sac, greatest-length, biparietal diameter, femur length, head circumference, and abdominal circumference. Using the means and standard deviations, growth curves were constructed, and the data used to develop predicted value charts for gestational age estimation. Using the predicted value charts established in our study, subsequent evaluation of pregnant baboons in our colony disclosed concordance with actual gestational age.