Sterility of the uterine cavity

In a prospective open study the sterility of the uterine cavity was evaluated in 99 women admitted for hysterectomy. The indications for hysterectomy were in most cases persistent irregular vaginal bleeding and fibromyomas of the uterus. Samples for both aerobic and anaerobic bacteria, Chlamydia trachomatis, yeasts and viruses were taken preoperatively from the apex of the vagina and cervical os. Immediately after hysterectomy the uterus was opened under sterile conditions and samples obtained from the isthmus and fundus of the uterine cavity for microbiological examination. Wet smears were taken from the same sites. Nearly a quarter of all the patients harbored one or more microorganisms in the uterus, mostly Gardnerella vaginalis, Enterobacter and Streptococcus agalactiae. We found that in a significant number of cases, the uterine cavity is colonized with potentially pathogenic organisms which may play a causative role in endometritis. The results indicate that inflammation of the uterine cavity should be evaluated by hysteroscopic examination before hysterectomy is undertaken in patients with persistent irregular vaginal bleeding.

A case-control study on post-caesarean endometritis-myometritis in Mozambique

Post-caesarean endometritis-myometritis (PCEM) was diagnosed in 49 Mozambican women. They were compared with 47 control women without signs of PCEM after caesarean section. The patients and controls were matched for age, parity and days post partum. Features of the socio-economic background and of past and current obstetric history were registered. Endocervical, intracavitary and blood cultures were carried out. Screening for syphilis seropositivity and HIV-1 and HIV-2 antibodies was performed. Socio-economic and obstetric background factors were similarly distributed in cases and referents, though previous caesarean section was less frequent among cases than among referents (OR 0.12). Moderate high-risk factors in existing antenatal card tended to be more frequent among cases than among referents (OR 3.29). Microbiological findings indicated more anaerobes in the vagina, in the endocervix and in the uterine cavity, though the differences only approached significance. It is concluded that women with PCEM in the setting studied expose few characteristic background features discriminating them from women with uneventful post-caesarean outcome. Further research efforts should be directed towards case-control studies with focus upon surgical factors and on a more comprehensive microbiology and serology approach.

Intrauterine bacterial findings in postpartum cows with retained fetal membranes

Eleven Swedish postpartum cows with retained fetal membranes (RFM) were studied to determine the intrauterine bacterial flora. Bacteriological examination was performed from twice weekly uterine biopsies. A total of 161 biopsies were collected during the first 8 weeks postpartum of which 82 (50.9%) were found with bacterial growth. Seventy-one of the 82 bacteria-positive biopsies (86.6%) showed mixed infections whereas the remaining 11 (13.4%) were pure cultures. Generally, a total of 322 isolates belonging to 12 different genera of bacteria, 6 facultative and 6 obligate anaerobic pathogens were identified. Mixed infections were most frequent for Actinomyces pyogenes together with obligate anaerobic bacteria, especially Bacteroides levii/spp. and Fusobacterium necrophorum. All of the studied cows had an infection that involved the first two genera of bacteria, whereas F. necrophorum was found in 8 of the 11 animals. The present work suggests that a possible pathogenic synergism between A. pyogenes and the two main Gram-negative anaerobes might have caused early endometritis and/or persistent infection.

Comparison of a PCR-based diagnostic assay for Mycoplasma pulmonis with traditional detection techniques

Current diagnosis of infection by Mycoplasma pulmonis, an important pathogen of laboratory rodent colonies worldwide, is based on serological, histopathological and culture techniques which can be slow and unreliable. A polymerase chain reaction (PCR) assay for M. pulmonis diagnosis was compared to current diagnostic methods. This PCR based technique allows a more specific, sensitive and rapid diagnosis of M. pulmonis from various tissues by comparison with culture and histopathology.

The effects of transcervical monofilament insertion on the microbial status of the uterus in guinea-pigs

The monofilament marker tail attached to intra-uterine contraceptive devices (IUCDs) has been implicated in the development of pelvic infection because it acts as a substrate for bacterial adhesion, and facilitates the transmission of vaginal bacteria into the uterus. A guinea-pig model was used to investigate the role of transcervical monofilaments in the transmission of vaginal bacteria into the uterus. By 21 days the degree of uterine contamination was significantly lower than after 24 h (P < 0.05), but was still significantly greater than control values (P < 0.01). Coating the monofilaments with poly (2-hydroxyethyl-methacrylate) (polyHEMA) had no effect on uterine bacterial counts at 24 h. After 21 days, however, contamination within the uteri fitted with polyHEMA-coated monofilaments had significantly increased from levels observed at 24 h (P < 0.01). These counts were also significantly greater than those recorded for the uncoated and control groups at the same time interval. In animals fitted with monofilaments, in which chlorhexidine had been incorporated into the polyHEMA coating, the level of uterine contamination after 24 h was significantly lower than that observed with uncoated threads at the same time interval (P < 0.02). After 21 days there was no significant difference between uterine bacterial counts from the chlorhexidine group and control animals. It is concluded that the use of such drug-loaded monofilaments offers the potential to minimize infections associated with the transcervical insertion of IUCDs.

Prevention of scrapie transmission in sheep, using embryo transfer

Reciprocal embryo transfers were made between scrapie-inoculated and scrapie-free sheep (Cheviot and Suffolk breeds) to measure scrapie transmission via the embryo (using offspring from embryos of scrapie-inoculated donors and scrapie-free recipients) and via the uterus (using offspring from embryos of scrapie-free donors and scrapie-inoculated recipients taken by cesarean section). Two control groups of offspring, 1 from scrapie-free parents (negative) and 1 from scrapie-inoculated parents (positive), also were included. All sheep were observed for clinical signs of scrapie until death or for a minimum of 60 months. Final diagnosis was made on the basis of histopathologic findings or results of mouse inoculation and/or proteinase-K-resistant protein analysis. Thirty to 61% of the scrapie-inoculated donor/recipient sheep within groups developed scrapie within 8 to 44 months after inoculation. None of the scrapie-free donor/recipients, including those gestating embryos from scrapie-inoculated donors, developed scrapie. Also, none of the offspring observed to > or = 24 months of age from reciprocal cross, via embryo (0/67), or via the uterus (0/25), or from the negative-control group (0/33) developed scrapie. Fifty-six of the offspring via embryo, 19 of these via the uterus, and 31 negative controls survived to > or = 60 months of age. Of the 21 sheep in the positive-control group, 2 (9.5%) developed scrapie, 1 at 31 months of age and 1 at 42 months of age. In the Cheviot offspring, the percentage of sheep carrying the short incubation allele ranged from 24 to 44% and the percentage in the Suffolk offspring ranged from 61 to 83%.(ABSTRACT TRUNCATED AT 250 WORDS)

The relationship between cycle stage and results of uterine culture in the mare

A total of 368 uterine swabs were taken from mares in heat (n = 202) and from mares that were not in heat (n = 166). From 72 of the mares, two swabs were taken; one during either seasonal anoestrus or dioestrus, and one during oestrus. Swabs were taken during anoestrus/dioestrus in 94 other mares and during oestrus in the remaining 130 mares. Bacteriological cultures were done aerobically and classified as negative, insignificant or significant. There was a trend for more positive cytological specimens during oestrus than during anoestrus/dioestrus. The proportions of significant cultures were 12 of 202 (5.9%) in oestrous mares and 14 of 166 (8.4%) in anoestrous/dioestrus mares. Generally more insignificant than negative cultures were obtained during oestrus compared to anoestrus/dioestrus. Seven of 27 cultures that were classified as significant were associated with positive cytological specimens, and only 2 of 16 specimens that yielded pure cultures of E. coli contained neutrophils. Although the culture results did not differ significantly between the cycle stages, oestrus should be the preferred time for uterine examination.

Shift in S-layer protein expression responsible for antigenic variation in Campylobacter fetus

Campylobacter fetus strains possess regular paracrystalline surface layers (S-layers) composed of high-molecular-weight proteins and can change the size and crystalline structure of the predominant protein expressed. Polyclonal antisera demonstrate antigenic cross-reactivity among these proteins but suggest differences in epitopes. Monoclonal antibodies to the 97-kDa S-layer protein of Campylobacter fetus subsp. fetus strain 82-40LP showed three different reactivities. Monoclonal antibody 1D1 recognized 97-kDa S-layer proteins from all C. fetus strains studied; reactivity of monoclonal antibody 6E4 was similar except for epitopes in S-layer proteins from reptile strains and strains with type B lipopolysaccharide. Monoclonal antibody 2E11 only recognized epitopes on S-layer proteins from strains with type A lipopolysaccharide regardless of size. In vitro shift from a 97-kDa S-layer protein to a 127-kDa S-layer protein resulted in different reactivity, indicating that size change was accompanied by antigenic variation. To examine in vivo variation, heifers were genetically challenged with Campylobacter fetus subsp. venerealis strains and the S-layer proteins from sequential isolates were characterized. Analysis with monoclonal antibodies showed that antigenic reactivities of the S-layer proteins were varied, indicating that these proteins represent a system for antigenic variation.

[Bacterial pathogen colonization of the uterus in puerperium]

In a prospective study the spectrum of bacteriological organisms in the uterus was analysed within the first 3 days post partum. Smears were taken from the ectocervix and from the cavum uteri from 80 asymptomatic puerperae (70 had delivered spontaneously and 10 had had a vaginal-operative delivery). The smears were achieved using an endometrium catheter with a pilot cap. After the specialised sampling had been undertaken, in 47 of the 70 patients with spontaneous delivery and in 1 of the patients with operative delivery, no bacterial invasion was found in the cavum uteri. After prophylactic administration of antibiotics prenatally, bacterial organisms were found significantly less often (p < 0.05). On the other hand, intrauterine bacterial organisms were found significantly more frequently in patients who had had cervix priming with PGE2 and where foetal blood analysis had been performed sub partum (p < 0.05). Contrary to the smears from the cavum uteri, all ectocervical smears were positive. In 13 of 23 cases with positive proof of intrauterine bacterial organisms, a difference was found in the bacteriological spectrum compared with the parallel cervical smear taken. Further obstetrical factors play a role in influencing the bacterial invasion, however, there were no complications in any of the cases due to the smears being taken and no infections were observed during the rest of the lying-in period.

The effects of antibiotics and steroids on the carriage of vaginal bacteria into the uterus during insertion of intra-uterine monofilaments in the guinea-pig

The effects of systemic norethisterone acetate and oxytetracycline hydrochloride on the levels of vaginal microorganisms found in the uterus after the insertion of transcervical, intra-uterine monofilaments in the guinea-pig were determined. The results indicated that bacteria were transferred to the uterus from the vagina during the insertion process and, in the presence of an intra-uterine substrate, persisted for up to 6 months. Daily treatment with norethisterone acetate or oxytetracycline hydrochloride whilst the monofilament was in-situ failed to reduce the bacterial numbers in the uterus. Similarly, daily treatment with oxytetracycline hydrochloride for the 5 days before monofilament insertion had no effect on these bacteria.

Bacterial flora detected in the uterine endometrial cavity of normal puerperae on the puerperal first day and on the puerperal fifth day after incidental use of cefpodoxime proxetil

In Japan, oral antimicrobial agents are prophylactically used with oxytocics after normal delivery to prevent puerperal infections. The present study was designed to investigate bacterial floras in the endometrial cavity immediately after normal delivery and the effect of prophylactic use of anti-microbial agents on those floras. Sixty-six puerperae who underwent uneventful courses of pregnancy and delivery were subjected for this study. Intrauterine contents were collected on the first day and the fifth day of the puerperium and submitted to microbiological examinations. Cefpodoxime proxetil (CPDX-PR) was orally given to the puerperae for prophylaxis for 5 days after the initial sampling. On the puerperal first day, a total of 98 strains (71 strains of aerobic bacteria, 27 strains of anaerobic bacteria) was detected in the uteri of the 66 subjects. The incidences of aerobic Gram-positive cocci, aerobic Gram-negative bacilli and anaerobic bacteria were 59.2%, 12.2%, 27.6% of the 98 strains, respectively. On the puerperal fifth day, a total of 82 strains (51 strains of aerobic bacteria and 31 strains of anaerobic bacteria) were detected in the uteri of the 66 subjects. The incidences of aerobic Gram-positive cocci, aerobic Gram-negative bacilli and anaerobic bacteria were 52.5%, 8.6% and 37.7% of 82 strains, respectively.

Uterine contamination in the guinea pig following transcervical uterine monofilament insertion

The effects of transcervical, intrauterine monofilaments on guinea pig uterine microflora were determined. The results indicated that bacteria were transferred to the uterus during the insertion process, although in sham control animals these bacteria were eradicated within 10 days. In the presence of an intrauterine substrate the bacteria within the uterus persisted for up to 6 months. Electron micrographs showed that bacteria were adhered to the monofilament within a biofilm, although some bacteria were planktonic.

Persistence of bovid herpesvirus-4 in experimentally inoculated pregnant rabbits

To study the persistence and reactivation of bovid herpesvirus-4 (BHV-4), pregnant rabbits were inoculated with BHV-4 via the intrauterine route. Disease production and virus shedding were monitored for up to 67 days post infection (DPI). Virus isolation was attempted from nasal, vaginal and buffy coat samples of all rabbits. Virus shedding was observed between 5 and 12 DPI but not thereafter. Some of the animals were given intramuscular injections of dexamethasone (DEX) for 4 consecutive days starting at 7 weeks post infection. One group of rabbits was euthanized at 5 days post-DEX treatment (58 DPI) and the other was euthanized 2 weeks post-DEX treatment (67 DPI). Virus shedding was not detected in either group but BHV-4 was recovered on multiple occasions from spleen, kidney, uterus, and ovary explants of both DEX-treated and non-treated rabbits indicating that BHV-4 can persist in these organs but cannot be reactivated by DEX. To further study the in vitro reactivation of persistent BHV-4, a methylating agent, hexamethylenebisacetamide (HMBA), was used in organ cultures of neural and extraneural tissues. Limited data on enhanced recovery of BHV-4 from spleen indicated that it may be the site of latency in BHV-4 infection.

Cryptococcal pneumonia and abortion in an equine fetus

Cryptococcus neoformans was the causative agent of pneumonia in a 9-month-old equine fetus aborted by a healthy American Paint mare. Endometritis was diagnosed on biopsy, and vaginal specimens obtained for culture were Cryptococcus-positive 1 month following abortion but not 5 months after abortion. Infection resolved without treatment between 1 and 5 months after abortion, and the mare was bred the following year and delivered a live premature foal without evidence of Cryptococcus infection.

Evaluation of progesterone treatment to create a model for equine endometritis

To investigate a model for equine endometritis, 12 mares with normal reproductive tracts were divided into 2 groups. All mares received progesterone in oil, 250 mg im, daily. At 5 days after initiation of progesterone administration, the uteri were inoculated with 10(6) colony forming units of Pseudomonas aeruginosa. The day of inoculation was designated Day 0. On Day 6, endometrial swab samples yielded P. aeruginosa in 5 mares; samples from the other 7 mares yielded heavy growth of Escherichia coli, Streptococcus zooepidemicus, Klebsiella pneumoniae, Enterobacter spp., Citrobacter diversus, Staphylococcus epidermidis and Streptococcus morbillorum. On Days 6, 7 and 8, Group A mares received intrauterine infusions of 6 g ticarcillin disodium and 0.2 g clavulanate potassium in 100 ml sterile saline. Group B mares received infusions of saline only. The incidence of swab specimens yielding no bacterial growth was significantly higher in Group A than Group B mares on Days 8 and 13 (4/6 vs 0/6). Swab samples from 5 of the 6 mares in Group A yielded growth of fungi on Days 13 and 19. Mares in Group B were then similarly treated with ticarcillin/clavulanate infusions, on Days 19, 20 and 21. The incidence of swab specimens yielding no bacterial growth was 2/6 and 1/6 on Days 21 and 26, respectively; fungi were not recovered from these mares at any time. The incidence of no-growth swabs after antibiotic treatment tended to be higher in Group A and incidence of fungal recovery after antibiotic treatment was significantly higher in Group A.(ABSTRACT TRUNCATED AT 250 WORDS)

Expression of an endogenous murine leukemia virus-related proviral sequence is androgen regulated and primarily restricted to the epididymis/vas deferens and oviduct/uterus

A cDNA representing a 5.2-kb defective, endogenous murine leukemia proviral sequence (EPI-EPS) was isolated from a C57BL/6 mouse cDNA epididymal library. Northern blot analysis demonstrated that EPI-EPS was predominantly expressed in the C57BL/6 mouse epididymis and vas deferens with 10-fold lower expression in the seminal vesicle, kidney, and submandibular gland. Analysis of tissues from other inbred strains of mice as well as the wild mouse, Mus musculus musculus, showed a similar pattern of tissue expression. EPI-EPS expression was also highly androgen regulated in both the reproductive and nonreproductive tissues of the C57BL/6 strain. However, a differential response to testosterone replacement was observed between tissues. Expression of EPI-EPS mRNA in the epididymis and vas deferens exhibited only a partial recovery to precastration levels after testosterone replacement; in the kidney and submandibular gland there was a complete recovery of EPI-EPS expression. Finally, EPI-EPS expression was also highly restricted in the female tissues, with expression limited to the oviduct and uterus. EPI-EPS, however, was not estrogen regulated in the female. These results suggest that a proviral sequence, EPI-EPS, is expressed in M. m. musculus and several inbred strains of mice due to its integration near a highly tissue-specific and androgen-regulated genetic locus.

Measurement of the cytotoxic effects of different strains of Mycoplasma equigenitalium on the equine uterine tube using a calmodulin assay

The cytopathic effects induced by five strains of Mycoplasma equigenitalium for cells of equine uterine tube explants were tested by measuring changes in cellular and extracellular concentrations of calmodulin (CaM). Calmodulin concentrations in samples of total homogenate (TH) and total homogenate supernates (THS) of the infected equine uterine tube explants were significantly lower than respective measurements on noninfected controls. In tissue culture medium fractions (TCM) of some infected explants, CaM concentrations were significantly higher than noninfected controls (p > 0.95). The results suggest that M. equigenitalium colonization on ciliated cells of the equine uterine tube can affect the permeability of the cell membrane leading to leakage or release of CaM during cell breakdown. Measurement of CaM concentrations in samples of TH revealed significant differences in the cytotoxic effects induced by different strains of M. equigenitalium on the equine uterine tube (EUT). The data suggests that some strains of M. equigenitalium may have a role in reproductive failure in the mare. In addition comparisons of the means of the concentrations of CaM in samples of TH or THS in EUT explants from four mares in the follicular and four in the luteal phase of the estrous cycle were found to be not significantly different.

Plasma concentrations of 13,14-dihydro-15-ketoprostaglandin F2 alpha in mares during uterine involution

Twelve mares were allowed to foal naturally, after which they were monitored to study uterine involution. Starting on day 3 after parturition, the internal genital tract was examined per rectum manually and ultrasonographically every other day for changes in uterine characteristics and ovarian activity. By day 5, gravid and nongravid uterine horns were similar in size, and by day 7, uterine fluid was absent. On day 7 after parturition, endometrial biopsy samples were obtained for histologic evaluation, and uterine swab specimens were obtained for microbiologic culture. Uterine swab specimens from 10 of 12 mares had slight bacterial growth. The uteri of 8 of the 12 mares were histologically involuted by day 7. All mares ovulated 7 to 12 days after parturition. Concentrations of 13,14-dihydro-15-keto-PGF2 alpha (PGFM) were measured in jugular plasma samples obtained daily for 21 days after parturition. Concentrations of PGFM were low by the day after parturition, and there was no significant correlation between uterine involution and PGFM concentrations in these mares. All 12 mares were bred at the first estrus after parturition, and 9 became pregnant.

Comparisons of the bacterial flora in genital regions at non-pregnancy

In the development of infectious diseases at non-pregnancy and at pregnancy, correlations between bacterial flora in the vagina and portio vaginalis and the ascending infections of those bacteria have recently been discussed. To clarify the cause of those infectious diseases, we studied the localization of microorganisms in genital regions. Patients undergone abdominal total hysterectomy (n = 172) were employed as subjects, and microorganisms isolated from 4 genital regions were studied. In addition, the preventive effect of cefmetazole (CMZ) against postoperative infections was analyzed in 479 cases including the hysterectomy cases mentioned above. The results obtained are summarized as follows: 1. The isolation rate of microorganisms at non-pregnancy, from subjects of 30 to 69 years old, was 65.6% (82/125) in the vagina and portio vaginalis, 52.1% (25/48) in the cervical mucus, 7.3% (9/124) in the uterine cavity and 0% (0/47) in the ovarian surface. 2. Numbers of microorganisms isolated in each region were 99 strains in the vagina and portio vaginalis, 28 in the cervical mucus, 10 in the uterine cavity and none in the ovarian surface. Isolation of aerobic Gram-positive bacteria (60-89.3%) and anaerobic Gram-positive bacteria (7.1-30%) were varied in each region. Lactobacillus spp. (38 strains), Staphylococcus epidermidis (20 strains) and Propionibacterium acnes (10 strains) were isolated from vagina and portio vaginalis, and Lactobacillus spp. (17 strains) were the most often isolated bacteria from the cervical mucus.(ABSTRACT TRUNCATED AT 250 WORDS)

Ancillary tests for assessment of the reproductive system

Ancillary tests applied to the male reproductive system include semen evaluation, ultrasonography, and testicular biopsy. Venereal disease testing and karyotyping are conducted on both male and female animals. The ancillary tests conducted on the female ruminant include culture, biopsy, cytology, and lavage; oviduct patency; and progesterone analysis. The application and interpretation of these tests as adjuncts to the physical examination of the reproductive system are discussed.

Genetic susceptibility to chlamydial salpingitis and subsequent infertility in mice

Groups of mice from genetically defined inbred strains were infected genitally with a pathogenic human strain of Chlamydia trachomatis and their subsequent fertility was compared. The CBA, C3H (H-2o) and C3H/He-mg (H-2k) mice were less fertile than control mice, at least up to 6 months after infection. In contrast, fertility was not impaired in BALB/c mice or in congenic BALB/K mice, which had the H-2k haplotype. Reduced fertility was paralleled by the extent of histological oviductal inflammation in mice of each strain. No salpingitis was seen 21 days after infection in the BALB strains, but lesions were apparent in CBA and C3H strains up to about 70 days after inoculation and these sometimes developed into hydrosalpinges. These results indicate that susceptibility to chlamydial salpingitis and subsequent infertility is under genetic control. This control was not simply associated with the major H-2 gene complex, as mouse strains of the same haplotype (H-2k) differed in susceptibility. The fertility of BALB/c (H-2d) and BALB/K (H-2k) strains was no different from that of controls, and congenic C3H mice of differing H-2 haplotypes (H-2k and H-2o) showed reduced fertility. Although all the infected F1 (BALB/K x C3H/He-mg) mice produced litters at the same rate as untreated controls, the litters were considerably smaller. This was due to the occurrence of unilateral pregnancies in the mice inoculated under the ovarian bursae and possibly also to early fetal death in mice inoculated directly in the uterus. These findings emphasize the importance of early diagnosis and treatment of infection of the lower genital tract of women.

Isolation of pathogenic strains of Haemophilus somnus from the female bovine reproductive tract

The prevalence of Haemophilus somnus in the genital tract of slaughtered and live cows in southern Ontario was investigated. The vagina and uterus of slaughtered cows were swabbed separately. Live cows were examined and sampled in two field surveys: Centre A and Centre B. In the former, aspirated mucus secretions and in the latter, specimens obtained by guarded swabbing were examined bacteriologically. Haemophilus somnus was isolated from 28 genital tracts of 461 slaughtered (6.1%), and seven of 199 live (3.5%) cows during the centre B survey. The isolates were recovered from both normal and diseased reproductive tracts. Fourteen strains isolated from genital organs were examined for pathogenicity in vivo to test the occurrence of pathogenic isolates. In the initial stage of the in vivo study on pathogenicity, each of the fourteen isolates was examined on one calf using an intracisternal inoculation. Subsequently, one pathogenic and one nonpathogenic strain were inoculated into five calves each to statistically confirm their pathogenic potential. Of 14 genital isolates of H. somnus examined in an intracisternal calf assay, six (43%) caused a fatal peracute neurological disease, while eight were nonpathogenic. A comparative pathological study of pathogenic and nonpathogenic isolates showed that the former caused a severe fatal suppurative meningoencephalitis whereas the latter caused no lesions whatsoever or a mild leukocytic leptomeningitis. The salient data obtained in this study indicate that there are pathogenic strains of H. somnus in the genital tract of apparently normal cows as well as of those with inflammatory disease.

Porcine conceptus proteins: antiviral activity and effect on 2',5'-oligoadenylate synthetase

Interferon-like proteins synthesized by conceptuses of domestic ruminants inhibit luteolysis during early pregnancy. Although pig conceptuses secrete trophoblast interferons during the period of CL maintenance, estrogen is involved with maintenance of the CL. The principal purposes of this work were to confirm production of trophoblast interferons by porcine conceptuses and to compare the effect of trophoblast interferons on endometrium of pigs and cattle. When measured using Madin-Darby bovine kidney (MDBK) cells challenged with vesicular stomatitis virus, antiviral activity in uterine flushings from cyclic gilts was not detectable throughout the estrous cycle; however, in pregnant gilts, antiviral activity increased from undetectable amounts to 4-11 x 10(3) U on Days 14, 16, and 18. Porcine embryos in culture produced 1,100 U/embryo/ml/24 h. Porcine conceptus secretory proteins induced 2',5'-oligo(A) synthetase in MDBK cells and in endometrial explants of cows but had no measurable effect on 2',5'-oligo(A) synthetase activity of endometrial explants of pigs. Similarly, endometrial 2',5'-oligo(A) synthetase of pregnant pigs was unaffected in vivo during the period of maximal synthesis of conceptus secretory proteins. Porcine conceptus secretory proteins produced no detectable increase in serum antiviral activity or 2',5'-oligo(A) synthetase activity of blood mononuclear leukocytes in utero-ovarian venous blood. These results suggest that conceptus interferons of pigs play different roles in the establishment of pregnancy compared to their roles in ruminants.