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Biomedical subjects

E D Watson

Publications and source records attributed to E D Watson.

At least 91 records · Page 5Linked to original sources
PubMed1990

Secretion of prostaglandins and progesterone by cells from corpora lutea of mares.

Corpora lutea (CL) were collected from mares during early (Day 4-5), mid- (Day 8-9), and late (Day 12-13) dioestrus. Dispersed cell suspensions were obtained by enzymic digestion of tissue. Two distinct luteal cell populations (large and small) were observed. The proportion of small luteal cells significantly increased as age of CL advanced. Cells (2 x 10(6)) from CL which were incubated for 24 h secreted prostaglandin (PG) F, PGE-2 and 6-keto-PGF-1 alpha (the stable metabolite of prostacyclin). Higher concentrations of all PGs were produced by cells from CL at early dioestrus than from those at mid- or late dioestrus. The ratio of PGF:PGE-2 increased from 0.33 in CL of early dioestrus to 1.34 in CL of mid-dioestrus, whereas ratios of PGF:6-keto-PGF-1 alpha remained relatively constant (approximately 0.6). The ratio of PGE-2:6-keto-PGF-1 alpha from CL decreased between early (3.27) and mid-dioestrus (0.43). Addition of LH, dbcAMP, or ionophore to cell cultures did not consistently affect secretion of progesterone or PGs by luteal cells. It is suggested that prostaglandins produced by luteal cells of mares may contribute to control of luteal function and that the changing ratios of prostaglandins may be more important in controlling the lifespan of the CL than absolute concentrations of each.

6-Ketoprostaglandin F1 alpha↗
PubMed1990

Immunosuppressive properties of follicular fluid from preovulatory horse follicles.

Fluid was aspirated from the preovulatory follicles of mares before and 12, 24 and 36 h after intravenous administration of hCG. Follicular fluid significantly (P less than 0.001) reduced lymphocyte blastogenesis in vitro and, at a dilution of 1:100, fluid collected at 36 h after administration of hCG was significantly more suppressive (P less than 0.01) than fluid collected before 36 h. Suppression of blastogenesis was reduced by extracting the follicular fluid with ether or by charcoal treatment (P less than 0.01) or by heating at 56 degrees C for 30 min (P less than 0.05). Preincubation of lymphocytes with 2 of 5 follicular fluid samples expressed subsequent blastogenesis. Follicular fluid inhibited blastogenesis of T-cell growth factor (TCGF)-dependent Con A lymphoblasts (P less than 0.05) and the degree of inhibition was related to time of addition of the TCGF and time of collection of the follicular fluid. These results indicate that preovulatory follicular fluid in the mare is increasingly suppressive to lymphocytes as time of ovulation approaches and that this immunosuppression is associated with an alteration of the response to lymphokine stimulation.

Animals↗
PubMed1990

Antibody response in the bovine genital tract to intrauterine infusion of Actinomyces pyogenes.

Antibody titres and immunoglobulin concentrations were measured in serum and in uterine and vaginal secretions from five heifers after intrauterine infusion of Actinomyces pyogenes. Infection stimulated an increase in uterine antibody titres of IgG2 and IgA, which approached significance. There was no increase in antibody titres in vaginal secretions or in serum. For each class of immunoglobulin, the ratio of specific antibody to immunoglobulin tended to increase in uterine secretions after infection, whereas no change was detected in the serum. These results indicate that at least a portion of the antibody was derived from local uterine synthesis.

Actinomyces↗
PubMed1990

Immunoreactive prostaglandin production by equine monocytes and alveolar macrophages and concentrations of PGE2 and PGF in bronchoalveolar lavage fluid.

Because of their capacity to produce prostanoids, alveolar macrophages may play a part in the pathogenesis of chronic obstructive pulmonary disease (COPD). Cultured equine alveolar macrophages and peripheral blood monocytes synthesised mainly prostaglandin (PG)F and PGE2. They also synthesised smaller quantities of PGI2, measured as the stable metabolite 6-keto-PGF1 alpha, and thromboxane B2. Concentrations of immunoreactive PGF and PGE2 were measured in bronchoalveolar lavage fluid collected from clinically normal horses (n = 3) and horses with COPD (n = 3). None of the normal horses had detectable concentrations of prostaglandins in lavage fluid, but fluid from all horses with COPD contained PGE2 (238 +/- 119 pg ml-1) and fluid from one of the three horses with COPD contained PGF (120 pg ml-1).

Animals↗
PubMed1989

Prostaglandin production by horse embryos and the effect of co-culture of embryos with endometrium from pregnant mares.

Embryos, endometrial biopsies, and uterine lavage fluid were collected from pregnant and non-pregnant mares 14 days after ovulation. Embryos were cultured for 20.5 h with and without endometrial tissue from pregnant mares, and endometrial tissue was cultured alone. Endometrial content of PGF tended to be higher (P = 0.06) in non-pregnant than in pregnant mares, but the amount of PGF released from tissue during culture was similar for pregnant and non-pregnant mares. Lavage fluid from non-pregnant mares also tended (P = 0.08) to contain higher concentrations of PGF. Coincubation of embryos with endometrium from pregnant mares significantly (P = 0.01) lowered concentrations of PGF in medium. Tissue concentrations and release of PGE-2 and 6-keto-PGF-1 alpha were similar in endometrial samples from pregnant and non-pregnant mares and prostaglandin production was unaffected by the presence of an embryo during incubation. Horse embryos released all three prostaglandins during a 20.5-h incubation.

6-Ketoprostaglandin F1 alpha↗
PubMed1989

Release of immunoreactive arachidonate metabolites by equine endometrium in vitro.

The ability of equine endometrium to release prostaglandin (PG) F, PGE2, and leukotriene (LT) B4 was studied in vitro, using endometrial tissue from diestrous mares. Because of the high cross-reactivity of the PGF antiserum with PGF1 alpha and with PGF2 alpha, results were quoted as total immunoreactive PGF. Significant concentrations of these arachidonate metabolites were released into tissue culture medium between 1 and 24 hours of incubation. Significantly higher concentrations of PGE, but not of PGE2 or LTB4, were released from endometria of mares with chronic endometritis than from genitally normal mares. Prostaglandin F was released only in low concentrations from the endometrium of a mare with pyometra, but concentrations of PGE2 and LTB4 were similar to those of genitally normal mares.

Animals↗
PubMed1989

In vitro function of bovine neutrophils against Actinomyces pyogenes.

Factors that influenced the in vitro bactericidal activity of bovine neutrophils against Actinomyces pyogenes were investigated. Neutrophils and serum from 2 clinically normal donor cows were incubated with bacteria for 2 hours. To determine bactericidal activity, colony-forming units were counted after a 48-hour incubation on blood agar plates. Microscopic examination indicated that in the presence of serum, bacteria were cell associated after incubation, whereas when serum was replaced by medium, bacteria were not cell associated. Bactericidal activity of neutrophils was similar whether the sera were heat-treated at 56 C for 30 minutes or were not heated. Heating the serum at 65 C for 30 minutes significantly (P less than 0.001) reduced bactericidal activity. Bactericidal activity decreased (P less than 0.001) as serum concentration (less than 10%) decreased. More than 80% of the bacteria were killed within the 40 minutes of incubation. The opsonizing capacity of serum varied significantly (P less than 0.01) among 12 cows. Similarly, neutrophil bactericidal activity (by cow) was affected significantly (P less than 0.001). Preincubation of serum with A pyogenes significantly (P less than 0.001) reduced the opsonizing ability of the serum. Culture filtrate of A pyogenes was not chemotactic for neutrophils in vitro.

Actinomyces↗
PubMed1989

Effect of prostaglandin F2 alpha on adrenal-produced steroid hormones in cows.

Ovariectomized, nonlactating cows were treated with IM injections of either physiologic saline solution or prostaglandin F2 alpha. Plasma concentrations of cortisol increased significantly by 30 to 60 minutes after injection of prostaglandin F2 alpha, but there were no significant increases in plasma concentrations of estradiol, progesterone, or testosterone. After saline solution treatment, there were no increases in any of the hormones measured.

Adrenal Glands↗
PubMed1989

Specific antibody in milk whey and phagocytosis of Actinomyces pyogenes by neutrophils in vitro.

Milk samples were collected from 21 non-pregnant cows to study the ability of milk whey to support in vitro bactericidal activity of neutrophils against Actinomyces pyogenes. Significant differences (P less than 0.01) existed in opsonising ability of milk whey samples from individual cows. Antibody titres to A pyogenes in milk whey were determined using an enzyme linked immunosorbent assay. Bactericidal activity of neutrophils incubated with milk whey was positively correlated (P less than 0.05) with titres of IgG2 and IgM antibodies but not with IgG1 or IgA antibodies.

Actinomyces↗
PubMed1988

Clinical report: Recovery of a degenerating 14-day embryo in the uterine flush of a mare 7 days after ovulation.

A 15-mm diameter degenerating embryonic vesicle and a normal, 200-u early blastocyst were recovered in a uterine flush of a mare 7 d after ovulation. From its size, the degenerating vesicle appeared to be 13 to 14 d of age. The mare had been bred during a previous cycle and then treated with prostaglandin 9 days after ovulation. The advanced vesicle that was recovered suggests that a conceptus from the previous cycle continued to grow for about 5 d after prostaglandin administration, and remained in the uterus during estrus, when plasma progesterone concentrations were below 1 ng/ml. From the estimated age of the conceptus, its development stopped at about the time the mare was inseminated. Had this conceptus survived through estrus and insemination, superfetation would have occurred.

Journal Article↗
PubMed1988

Use of hyperimmune serum in treatment of endometritis in mares.

Endometritis was induced in four progesterone-treated ovariectomized mares and in two seasonally anestrous mares by intrauterine infusion of Streptococcus zooepidemicus. The bacteria were suspended in phosphate buffered saline (PBS), or in nonimmune or hyperimmune serum. Uterine lavage was performed after 24 h. Significantly fewer (P < 0.05) bacteria were recovered from mares which received hyperimmune serum than from mares which received nonimmune serum or PBS. There was no significant difference between treatment with nonimmune serum or PBS. It is therefore suggested that increasing the availability of specific antibody reduced the severity of intrauterine infection.

Journal Article↗
PubMed1988

Concentrations of immunoreactive leukotriene B4 in uterine lavage fluid from mares with experimentally induced and naturally occurring endometritis.

Acute endometritis was induced in ovariectomized pony mares by infusion of a 1% solution of oyster glycogen. Maximum concentrations of immunoreactive leukotriene B4 in uterine washings coincided with the greatest rate of infiltration of neutrophils into the uterine lumen. Concentrations of immunoreactive leukotriene B4 decreased to basal levels 6 h after infusion and were unaffected by administration of ovarian steroids to ovariectomized mares. Uterine washings from mares with persistent endometritis did not contain significantly different concentrations of leukotriene B4 from genitally normal mares.

Animals↗
PubMed1988

Effect of ovarian steroids on migration of uterine lumenal neutrophils and on chemokinetic factors in uterine secretions from mares.

Incubation of blood neutrophils with uterine flushings collected from ovariectomised mares treated with oestradiol, stimulated migration under agarose, whereas flushings from mares treated with progesterone or oily vehicle, inhibited migration. After intra-uterine infusion of bacteria, however, flushings from oestradiol-treated and vehicle-treated mares inhibited migration, whereas progesterone treatment stimulated migration. Migration of uterine-derived neutrophils under agarose was less than that of blood neutrophils and was not influenced by treatment with ovarian steroids. Uterine susceptibility to infection in progesterone-treated mares was not, therefore, correlated with the migratory activities of uterine neutrophils or the chemokinetic properties of uterine secretions in vitro.

Animals↗
PubMed1988

Macrophage clearance of 125I-labelled polyvinyl pyrrolidone in the horse: effect of ovarian steroids and persistent endometritis.

The rate of clearance of 125I-labelled polyvinyl pyrrolidone (PVP) from blood was measured in mares as an indicator of macrophage function. In three out of four cycling mares, PVP clearance was slower during oestrus than dioestrus. Similarly, administration of oestrogen to four ovariectomised mares tended to depress PVP clearance compared with clearance from the same mares before they received oestrogen. However, the effect of oestrogen was not statistically significant. Mares susceptible to persistent endometritis had rates of PVP clearance which were similar to those of genitally normal mares.

Animals↗
PubMed1988

Plasma cell numbers in uteri of mares with persistent endometritis and in ovariectomised mares treated with ovarian steroids.

Immunoglobulins A, G and M were localised by immunoperoxidase staining of endometrial sections from ovariectomised mares. Treatment with progesterone or oestradiol-17 beta did not significantly affect numbers of cells secreting any of the isotypes. Mares with persistent endometritis did not have significantly greater numbers of endometrial plasma cells than genitally-normal mares.

Animals↗