Controlled, double-blind, randomized trial to assess the efficacy and safety of hydroxychloroquine chemoprophylaxis in SARS CoV2 infection in healthcare personnel in the hospital setting: A structured summary of a study protocol for a randomised controlled trial

Background

SARS-CoV-2 infection presents a high transmission in the group of health professionals in Spain (12-15% infected). Currently there is no accepted chemoprophylaxis but hydroxychloroquine (HDQ) is known to inhibit the coronavirus in vitro. Our hypothesis is that oral administration of hydroxychloroquine to healthcare professionals can reduce the incidence and prevalence of infection as well as its severity in this group.

Methods

Design: Prospective, single center, double blind, randomised, controlled trial (RCT). Participants: Adult health-care professionals (18-65 years) working in areas of high exposure and high risk of transmission of SARS-COV-2 (COVID areas, Intensive Care Unit –ICUs-, Emergency, Anesthesia and all those performing aerosol-generating procedures) will be included. Exclusion criteria include previous infection with SARS CoV2 (positive SARS-CoV-2 PCR or IgG serology), pregnancy or lactation, any contraindication to hydroxychloroquine or evidence of unstable or clinically significant systemic disease.

Interventions

Patients will be randomized (1:1) to receive once-daily oral Hydroxychloroquine 200mg for two months (HC group) or placebo (P group) in addition to the protective measures appropriate to the level of exposure established by the hospital. A serological evaluation will be carried out every 15 days with PCR in case of seroconversion, symptoms or risk exposure. Primary outcome is the percentage of subjects presenting infection (seroconversion and/or PCR +ve) by the SARS-Cov-2 virus during the observation period. Additionally, both the percentage of subjects in each group presenting Pneumonia with severity criteria (Curb 65 ≥2) and that of subjects requiring admission to ICU will be determined.

Discussion

While awaiting a vaccine, hygiene measures, social distancing and personal protective equipment are the only primary prophylaxis measures against SARS-CoV-2, but they have not been sufficient to protect our healthcare professionals. Some evidence of the in vitro efficacy of hydroxychloroquine against this virus is known, along with some clinical data that would support the study of this drug in the chemoprophylaxis of infection. However, there are still no data from controlled clinical trials in this regard. If our hypothesis is confirmed, hydroxychloroquine can help professionals fight this infection with more guarantees.

Participants

This is a single-center study that will be carried out at the Marqués de Valdecilla University Hospital.

450 health professionals working at the Hospital Universitario Marqués de Valdecilla in areas of high exposure and high risk of transmission of SARS COV2 (COVID hospital areas, Intensive Care Unit, Emergency, Anesthesia and all those performing aerosol-generating procedures) will be included.

Inclusion criteria: 1) Health professionals aged between 18 and 65 years (inclusive) at the time of the first screening visit; 2) They must provide signed written informed consent and agree to comply with the study protocol; 3) Active work in high exposure areas during the last two weeks and during the following weeks.

Exclusion criteria: 1) Previous infection with SARS CoV2 (positive coronavirus PCR or positive serology with SARS Cov2 negative PCR and absence of symptoms); 2) Current treatment with hydroxychloroquine or chloroquine; 3) Hypersensitivity, allergy or any contraindication for taking hydroxychloroquine, in the technical sheet; 4) Previous or current treatment with tamoxifen or raloxifene; 5) Previous eye disease, especially maculopathy; 6) Known heart failure (Grade III to IV of the New York Heart Association classification) or prolonged QTc; 7) Any type of cancer (except basal cell) in the last 5 years; 6) Refusal to give informed consent; 8) Evidence of any other unstable or clinically significant untreated immune, endocrine, hematological, gastrointestinal, neurological, neoplastic or psychiatric illness; 9) Antibodies positive for the human immunodeficiency virus; 10) Significant kidney or liver disease; 11) Pregnancy or lactation.

Intervention and comparator

Two groups will be analyzed with a 1: 1 randomization rate.

Intervention: (n = 225): One 200 mg hydroxychloroquine sulfate coated tablet once daily for two months.

Comparator (control group) (n = 225): One hydroxychloroquine placebo tablet (identical to that of the drug) once daily for two months

Main outcomes

The primary outcome of this study will be to evaluate:

number and percentage of healthcare personnel presenting symptomatic and asymptomatic infection (see “Diagnosis of SARS CoV2 infection” below) by the SARS-Cov2 virus during the study observation period (8 weeks) in both treatment arms;

number and percentage of healthcare personnel in each group presenting with Pneumonia with severity criteria (Curb 65 ≥2) and number and percentage of healthcare personnel requiring admission to the Intensive Care Unit (ICU) in both treatment arms.

Diagnosis of SARS CoV2 infection

Determination of IgA, IgM and IgG type antibodies against SARS-CoV-2 using the Anti-SARS-CoV-2 ELISA kit (EUROIMMUN Medizinische Labordiagnostika AG, Germany) every two weeks. In cases of seroconversion, a SARS-CoV-2 PCR will be performed to rule out / confirm an active infection (RT-PCR in One Step: RT performed with mastermix (Takara) and IDT probes, following protocol published and validated by the CDC Evaluation of COVID-19 in case of SARS-CoV-2 infection

Randomisation

Participants will be allocated to intervention and comparator groups according to a balanced randomization scheme (1: 1). The assignment will be made through a computer-generated numeric sequence for all participants

Blinding (masking)

Both participants and investigators responsible for recruiting and monitoring participants will be blind to the assigned arm.

Numbers to be randomised (sample size)

Taking into account the current high prevalence of infection in healthcare personnel in Spain (up to 15%), to detect a difference equal to or greater than 8% in the percentage estimates through a two-tailed 95% CI, with a statistical power of 80% and a dropout rate of 5%, a total of 450 participants will need to be included (250 in each arm).

Trial Status

The protocol approved by the health authorities in Spain (Spanish Agency for Medicines and Health Products “AEMPS”) and the Ethics and Research Committee of Cantabria (CEIm Cantabria) corresponds to version 1.1 of April 2, 2020.

Currently, recruitment has not yet started, with the start scheduled for the second week of May 2020.

Trial registration

Eudra CT number: 2020-001704-42 (Registered on 29 March 2020)

Full protocol

The full protocol is attached as an additional file, accessible from the Trials website (Additional file 1). In the interest in expediting dissemination of this material, the familiar formatting has been eliminated; this Letter serves as a summary of the key elements of the full protocol.

The study protocol has been reported in accordance with the Standard Protocol Items: Recommendations for Clinical Interventional Trials (SPIRIT) guidelines (Additional file 2).

Visual Inspection for Caries Detection

We aimed to perform a systematic review including a meta-analysis to evaluate the overall accuracy of visual methods for detecting carious lesions and to identify possible sources of heterogeneity among the studies included. Two reviewers searched PubMed, Embase, Scopus, and other sources through July 2014 to identify published and nonpublished studies in English. Studies of visual inspection were included that 1) assessed accuracy of the method in detecting caries lesions; 2) were performed on occlusal, proximal, or free smooth surfaces in primary or permanent teeth; 3) had a reference standard; and 4) reported sufficient data about sample size and accuracy of methods. The data were used to calculate the pooled sensitivity, specificity, diagnostic odds ratio, and summary receiver operating characteristics curve. Heterogeneity of the studies was also assessed. A total of 102 manuscripts (from 5,808 articles initially identified) and 1 abstract (from 168) met the inclusion criteria. In general, the analysis demonstrated that the visual method had good accuracy for detecting caries lesions. Although laboratory and clinical studies have presented similar accuracy, clinically obtained specificity was higher. We also observed moderate to high heterogeneity and evidence of publication bias in most papers. Moreover, studies employing widely recognized visual scoring systems presented significantly better accuracy as compared to studies that used their own criteria. In conclusion, visual caries detection method has good overall performance. Furthermore, although the identified studies had high heterogeneity and risk of bias, the use of detailed and validated indices seems to improve the accuracy of the method.

Influence of examiner experience on clinical performance of visual inspection in detecting and assessing the activity status of caries lesions

Our hypothesis was that a method of caries activity evaluation based on the clinical features of the lesions would be less time consuming but more influenced by the examiner's experience than the scoring system used in association with the International Caries Detection and Assessment System (ICDAS). Thus, the aim of this study was to evaluate the performance of three groups of examiners with different levels of experience using two different methods to assess the activity status of caries lesions by visual inspection. A cross-sectional study in a dental office setting was performed selecting 18 children, aged three to eight years, who had sought dental treatment at a dental school. Examinations to detect caries lesions were performed using visual inspection by six examiners with different levels of experience: two undergraduate dental students, two specialists in pediatric dentistry, and two graduate students. The examiners used ICDAS and two different methods to assess caries activity: using an additional score system or considering the examination of clinical features. Two benchmark examiners examined the children in a joint session, and their consensus was considered to be the reference standard. The sensitivity, specificity, and reproducibility were calculated for different thresholds: all, cavitated, and active caries lesions. Multilevel analyses were performed to compare the different methods and examiners. No differences were observed among the examiners, either in detecting all lesions and cavitated lesions or regarding the activity assessment. The methods of assessing activity status performed similarly, but the time spent on examinations was shorter for the method evaluating clinical features. In conclusion, the experience of examiners does not significantly influence the performance of visual inspection, and both methods of assessing activity status result in similar diagnostic accuracy.

Leflunomide derivative FK778 inhibits production of antibodies in an experimental model of alloreactive T-B cell interaction

OBJECTIVES

The contribution of humoral immune response in allograft and xenograft rejection has been clearly demonstrated in recent years. For this reason, inhibition of alloantibody production has become essential in managing transplanted patients. Here, we assessed the effects of the leflunomide derivative FK778 (FK778) in the control of antibody production resulting from semiallogeneic cognate T-B-cell interactions.

MATERIALS AND METHODS

BALB/c mice were tolerized at birth with semiallogeneic spleen cells from (BALB/c X C57BL/6) F1 mice, with or without overexpression of human bcl-2 transgene in B cells. These tolerized mice were treated with different dosages of FK778, either from birth, or from the third week of age, when autoantibody production was detected. The production of autoantibodies, used as markers of semiallogeneic cognate T-B - cell interactions, was evaluated at different time points during drug administration or after the interruption of treatment.

RESULTS

FK778 treatment started at birth inhibited the production of semiallogeneic-driven antibodies in a dose-dependent manner. In addition, FK778 also reduced the levels of preformed circulating autoantibodies in adult mice, although the dosage required was 4 times higher than that used in neonates. However, the levels of IgG antibodies in these tolerized mice increased after FK778 withdrawal, indicating that FK778 failed to induce tolerance to semiallogeneic host CD4+ Th2 and/or donor B cells.

CONCLUSIONS

Our results demonstrate the efficacy of FK778 in the control of antibody production resulting from semiallogeneic cognate T-B - cell interactions.

Secretion of oxytocin in pregnant and parturient cows: corpus luteum may contribute to plasma oxytocin at term

Plasma oxytocin (OT) concentrations were determined in 14 late-pregnant and parturient Angus-Hereford cows. Jugular and utero-ovarian veins were cannulated for simultaneous withdrawal of blood samples. Samples were collected at 10-min intervals for 6 h once weekly beginning 60-14 days before the date of expected delivery (group 1), or daily 3-7 days before the due date (group 2). In a third group, samples were collected at 15-min intervals every other day for 12 h beginning 1 wk before calving. Basal levels of OT were low, the overall mean for both veins was 0.46 +/- 0.03 microU/ml until a week before parturition, and then increased to 0.77 +/- 0.1 microU/ml (P < 0.02). Spurts of OT occurred intermittently on all days. Interpeak intervals averaged 71.0 +/- 10.7 min until Day -14, and from Day -14 to Day -1 the intervals were 44.0 +/- 5.3 min (P < 0.05). From Day -60 to Day -25 the amplitudes of OT peaks were low and similar in both veins (mean 1.37 +/- 0.1 microU/ml). From Day -14 to Day -1 the peak amplitudes were 3.6 +/- 0.4 microU/ml on average (P < 0.02). During the last 2 wk the utero-ovarian peak of OT was frequently higher than the peripheral peak. In addition, a number of spurts were observed in the utero-ovarian vein only (solo peaks). On the day of parturition during the first stage of labor, peak amplitudes had increased to 7.3 +/- 2.0 microU/ml, and the interpeak intervals had become shorter than before labor (mean 25.1 +/- 2.6 min). A large surge of OT initiated the expulsive stage of labor. Basal levels rose to 43.1 +/- 16 microU/ml and 38.7 +/- 12.6 microU/ml, and peak levels to 77.4 +/- 19.1 microU/ml and 91.6 +/- 21 microU/ml in the jugular and utero-ovarian veins, respectively. Interpeak intervals had decreased to 17.2 +/- 3.3 min (P < 0.05). Oxytocin levels remained high after delivery of the calf until the placenta was expelled. The posterior pituitary was the source of circulating OT during most of gestation and labor, but the solo peaks observed during late gestation in the utero-ovarian vein were probably of luteal origin or possibly of caruncular origin, because near term, both tissues express OT mRNA. Fetal posterior pituitary is another possible source for these peaks. Our conclusions are that during bovine pregnancy, low amplitude spurts of OT are secreted intermittently; near term, both the frequency and peak amplitude of the spurts increase; and during labor, a dramatic increase in plasma OT precedes the expulsion of the calf. The main source of OT is the posterior pituitary, but near term, a utero-ovarian source secretes additional OT into the systemic circulation.

Use of the GnRH analogue, deslorelin acetate, in a slow-release implant to accelerate ovulation in oestrous mares

In two separate controlled clinical trials, the efficacy and safety of 2.2 mg of the GnRH analogue deslorelin, administered subcutaneously as a short-term implant to normally cycling mares in oestrus with a dominant ovarian follicle more than 30 mm in diameter, were evaluated, using a placebo as a negative control. The oestrous cycle of each mare was followed by teasing, palpation per rectum and transrectal ultrasonography. Follicles were monitored every 24 hours by ultrasonography until ovulation occurred. The mares were either mated naturally or inseminated artificially. In trial 1, 174 mares were treated at six locations in Canada, and in trial 2, 98 mares were treated at three locations in the USA. In trial 1, the treatment with deslorelin reduced the mean (sd) time to ovulation from 84.2 (48.4) hours to 50.2 (19.6) hours (P < 0.001) and in trial 2 it reduced it from 88.8 (40.3) hours to 54.1 (26.5) hours (P < 0.001). In trial 1, the percentage of mares ovulating within 48 hours increased from 37.7 per cent in control mares to 86.1 per cent in treated mares (P < 0.001) and in trial 2 the percentage increased from 26.5 to 80.9 per cent (P < 0.001). In trial 2, the duration of oestrus in the deslorelin-treated mares was reduced from 6.1 days to 4.3 days and the number of matings or artificial inseminations was reduced from 2.5 to 1.7 (P < 0.001). In trial 1, days 12 to 20 pregnancy rates for matings at the treatment oestrus were not different for deslorelin-treated (75.6 per cent) and placebo-treated (66.1 per cent) mares. In trial 2, days 12 to 20 pregnancy rates from matings at the treatment oestrus were lower for deslorelin-treated (58.7 per cent) than for placebo-treated (83.3 per cent) mares (P < 0.05), although pregnancy rates were similar for deslorelin-treated (97.1 per cent) and placebo-treated (95.0 per cent) mares after mating at the second oestrus. In both trials, pregnancy losses due to early or late abortions were within the normally expected range and similar for deslorelin-treated (3.6 and 3.7 per cent, respectively) and placebo-treated (13.4 and 7.5 per cent) mares. The treatments did not cause systemic side effects and local reactions at the implantation sites were slight and of short duration.

Estrogens and prostaglandin F2α in the semen and blood plasma of stallions

A study was performed to determine the levels of estrogens and prostaglandin F2alpha in the stallion ejaculate. Simultaneous semen and blood plasma samples were collected from 19 stallions, 2 weeks apart, during the breeding season. Although not statistically different, the total mean estrogen content tended to be higher in seminal plasma (4447 pg/ml) than in blood (2497 pg/ml). A tendency was found for higher mean estrone sulphate concentrations than for total free steroid in both seminal (4116.1 vs 330.5 pg/ml) and blood plasma (2447.1 vs 49.5 pm/ml). Mean concentrations of estrone in ejaculate and blood plasma were 257.1+/-267.0 (SD) and 9.5+/-5.4 pg/ml, respectively. Estradiol-17beta concentrations were 73.4+/-87.4 and 40.0+/-27.6 pg/ml in ejaculates and blood plasma, respectively. Mean PGF2alpha concentrations tended to be much higher than total estrogens (1106.8+/-1636.4, SD, vs approximately 260 ng/ejaculate, respectively). To our knowledge this is the first report of PGF2alpha and estrogen concentrations in the stallion ejaculate.

Is nutritional anestrus precipitated by subfunctional corpora lutea in beef cows?

Thirty-four multiparous, lactating, cyclic beef cows which calved in moderate body condition were used to determine effects of restricted nutrition on corpus luteum (CL) development and endocrine status. At 78 d postpartum, six cows were assigned to a control (CON) diet (26.0 Mcal ME), fed to increase bodyweight (BW) and body condition score (BCS), and the remaining 28 cows were fed to lose BW and BCS on a restricted (RES) diet (14.0 Mcal ME). Following a 40-d adjustment period on respective diets, estrous cycles were synchronized and cows bled daily for determination of progesterone (P4), luteinizing hormone (LH) and insulin (INS) beginning at the synchronized estrus. Ultrasonography was used to determine the ovulatory follicle and CL development. Control cows were maintained for one estrous cycle and were ovariectomized on day 11 of their second cycle. Ten cows on restricted diet (RES-C) continued to form a functional CL (P4 > 1.5 ng/ml at day 10 of an estrous cycle) through as many as 5 cycles, after which observations were discontinued. Fourteen cows on restricted diet (RES-A) were ovariectomized on day 11 of a cycle when a CL was identified by ultrasonography, but was subfunctional (P4 < 1.5 ng/ml on day 10 of that cycle). Four additional RES-A cows which had subfunctional CL were not ovariectomized but were bled for an additional 25 d. At ovariectomy, CL and ovarian weights were collected. Luteal tissue was prepared for evaluation of P4 synthesis, LH responsiveness in vitro, and for determination of P4 content and total LH receptors. Bodyweight and BCS increased in CON cows; whereas, RES cows lost BW and BCS (P < .05). In the cycle prior to ovariectomy, serum P4 and LH were not different in 18 RES-A cows which developed subfunctional CL in comparison to CON cows. Four RES-A cows not ovariectomized but bled for an additional 25 d neither exhibited estrus, ovulated, nor had P4 concentrations greater than .3 ng/ml. Serum INS was lower in RES-A cows during the cycle prior to ovariectomy than in CON cows (P < .05). During the 11-d period prior to ovariectomy, mean serum P4 and INS were lower in RES-A cows than in CON cows (P < .05); however, serum LH was not different. Furthermore, CL and ovarian weights, P4 content of CL, secretion of P4 by luteal tissue in response to LH in vitro and LH receptor number were not different between CON and RES-A cows. In conclusion, nutritional anestrus may be preceded by the formation of a CL with lower steroidogenic output in vivo. However, luteal tissue, collected from RES-A cows, did not appear to be subfunctional during in vitro incubation when substrate availability and gonadotropin support were equal between diets.

Influence of phospholipids on ruminal fermentation in vitro and on nutrient digestion and serum lipids in sheep

Phospholipid supplements were incubated in vitro or fed to sheep to determine how they affected ruminal fermentation, nutrient digestion and serum lipid concentration. In vitro, deoiled soybean lecithin added to hay increased (P less than .05) total VFA concentration but had no effect on fiber digestion in four of five trials. Purified phospholipid (synthetic phosphatidylethanolamine), however, had little effect on in vitro hay fermentation when tested at four levels (0, 10, 20 or 30 mg) in three separate trials. Deoiled soybean lecithin disappeared in vitro at two rates, 12.9 and .66%/h for the fast- and slow-degrading fractions, respectively. Compared with 2.4% corn oil supplements, 5.2% soybean lecithin added to sheep diets (56% concentrate) reduced (P less than .05) energy, fiber and nitrogen digestibilities. Crude lecithin reduced (P less than .05) energy digestibility more than deoiled lecithin. Both types of lecithin increased (P less than .05) serum nonesterified fatty acid concentrations but had no effect on serum glucose, cholesterol or triglyceride concentrations compared with the corn oil diet. In summary, phospholipids had different effects on ruminal fermentation, depending on their source. None had a beneficial effect on fiber digestion. Phospholipids are degraded in the rumen and inhibit digestion in a manner similar to that of the commercial fats and oils.

Effect of holding time and temperature of bovine whole blood on concentration of progesterone, estradiol-17β and estrone in plasma and serum samples

Bovine jugular venous blood was collected, with and without heparin, and aliquoted into 140 12-ml tubes. Four subsamples (two heparinized and two coagulated) were centrifuged immediately (time zero) and plasma or serum was aspirated and stored at -20 degrees C. One-half of the remaining subsamples were stored at 4 degrees C and the other one-half at 25 degrees C (room temperature). At 1-h intervals (0 to 24 h), 6-h intervals (24 to 72 h) and at 96 and 120 h, four subsamples (heparinized and coagulated at both 4 degrees C and 25 degrees C) were centrifuged, plasma or serum was aspirated and stored at -20 degrees C. Whole blood incubation for 1 h at 25 degrees C reduced mean plasma and serum progesterone (P(4)) concentration (P<0.05). Similarly, whole blood incubation at 4 degrees C for 2 and 3 h, respectively, reduced mean plasma and serum P(4) concentration (P<0.05). No difference was found in mean P(4) concentration between plasma and serum samples harvested from whole blood incubated at 4 degrees C or 25 degrees C. Concentration of estradiol-17beta (E(2)) and estrone (E(1)) fluctuated over time, irrespective of holding temperature. There was a blood type, heparinized or coagulated, by time interaction (P<0.01) for both E(2) and E(1) concentrations It was concluded that incubation time and temperature between collection and centrifugation of bovine blood samples influenced the assayable P(4) concentration in both plasma and serum. In contrast, incubation temperature had no effect on assayable E(2) and E(1) concentrations, but assayable E(2) and E(1) over time were differentially affected, depending on whether plasma or serum was assayed.

A study of the source of estradiol-17 beta in the bull

A study was designed to determine if the bull testes secretes estradiol-17 beta, as has been reported for several other species. Two experiments were conducted. In the first experiment, five Angus-sired crossbred bulls were fitted with catheters in the spermatic and jugular veins and sampled every 15 min for six hours. One was bled from three cannula, the third being in the spermatic artery. In the second experiment, these same bulls were castrated and jugular vein blood was collected at timed intervals for two hours. Plasma samples were assayed for estradiol-17 beta (E2) and testosterone (T) using highly specific radioimmunoassays. This experiments gave evidence that: a. Concentrations of E2 were significantly lower (P less than .05) in the jugular vein than the spermatic vein in each of the five bulls, although the mean concentration for all bulls was not great for either vein nor was the difference great between the two veins. In confirmation of past studies, T concentration in the jugular vein was much lower than in the spermatic vein in each bull as was overall mean. b. Removal of the testes caused E2 to decrease during the 25 min post-castration but the difference was not significant (P greater than .05), whereas T decreased 4-fold (P less than .01). During the next 95 min., the concentrations of both hormones increased 3- and 6-fold, respectively, as did cortisol concentration. It is concluded that the bull testes secretes E2, but the secretion is minor to that of T and that another source of both hormones can be the adrenal gland, such as during stress.(ABSTRACT TRUNCATED AT 250 WORDS)

Prostaglandin E2 counteracts the effects of PGF2 alpha in indomethacin treated cycling gilts

Twenty crossbred gilts with at least 2 consecutive estrous cycles of 18 to 21 days in length were used to study the effects of prostaglandins E2 and F2 alpha (PGE2 and PGF2 alpha) on luteal function in indomethacin (INDO) treated cycling gilts. Intrauterine and jugular vein catheters were surgically placed before day 7 of the treatment estrous cycle and gilts were randomly assigned to 1 of 5 treatment groups (4/group). With exception of the controls (Group I) all gilts received 3.3 mg/kg INDO every 8 h, Groups III, IV and V received 2.5 mg PGF2; 2.5 mg PGF2 alpha + 400 micrograms PGE2 every 4 hr, or 400 micrograms PGE2 every 4 h, respectively. All treatments were initiated on day 7 and continued until estrus or day 23. Jugular blood for progesterone analysis was collected twice daily from day 7 to 30. Estradiol-17 beta (E2-17 beta) concentrations were determined in samples collected twice daily, from 2 d before until 2 d following the day of estrus onset. When compared to pretreatment values, estrous cycle length was unaffected (P greater than 0.05) in Group I, prolonged (P less than 0.05) in Groups II, IV and V; and shortened (P less than 0.05) in Group III. The decline in plasma progesterone concentration that normally occurs around day 15 was unaffected (P greater than .05) in Group I; delayed (P less than 0.05) in Groups II, IV and V; and occurred early (P less than 0.05) in Group III. Mean E2-17 beta remained high (31.2 +/- 4.9 to 49.3 +/- 3.1 pg/ml) in Groups III and IV, while the mean concentrations in Groups III and V varied considerably (17.0 +/- 2.0 to 52.2 +/- 3.5 pg/ml). The results of this study have shown that PGE2 will counteract the effects of PGF2 alpha in INDO treated cycling gilts. The inclusion of PGF2 alpha appeared to either stimulate E2-17 beta secretion or maintain it at a higher level than other treatments.

Sparing effects of intrauterine treatment with prostaglandin E2 on luteal function in cycling gilts

Twelve crossbred gilts, 8 to 9 months of age, were used to study the effects of prostaglandin E2 (PGE2) on luteal function during the estrous cycle. Intrauterine and jugular vein catheters were surgically placed before day 7 of the treatment estrous cycle and gilts were randomly assigned to 1 of 3 treatment groups. Groups I and II received constant intrauterine infusion of vehicle (6.0 ml/24 hr) or PGE2 (2400 micrograms/day; 6.0 ml/24 hr) respectively; while group III was given intrauterine infusions of 400 micrograms PGE2 every 4 hr. All infusions were initiated on day 7 and continued until estrus or through day 23. Jugular blood samples were collected twice daily from days 7 to 30 for progesterone analysis. Intrauterine infusion of PGE2 at the dose and frequencies given in this study delayed the decline in jugular plasma progesterone and resulted in prolongation of the estrous cycle length. The results of this study have shown that PGE2 at the dosage and frequency of administration used was capable of extending corpus luteum function.

Secretory patterns of progesterone and gonadotropins in the ovarian branch of the ovarian vein and the jugular vein during and around the second trimester of pregnancy in the cow

Indwelling catheters were placed in the ovarian branch of the ovarian vein (OBOV) of 14 pregnant beef cows assigned to one of three periods of gestation: Period 1, catheterization on Days 70-100 (n = 5); Period 2, Days 120-150 (n = 5); and Period 3, Days 180-210 (n = 4). Samples were collected from the OBOV twice daily at 0600-0800 h (AM) and 1700-1900 h (PM). Intensive sample collections (every 20 min for 6 h, short-term sampling windows) were performed from the jugular vein (JV) and the OBOV. Average and baseline OBOV progesterone (P4) concentrations per 6-h window as well as the magnitude and amplitude of OBOV P4 pulses decreased from Period 1 to Period 2. The number of pulses per window and the relative increase of pulses above the baseline did not change. There was an increase in the average, but not the baseline, concentration of OBOV P4 from Period 2 to Period 3. The average and baseline concentrations of P4 in the JV as well as luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in the OBOV and JV remained constant from Day 70 to Day 210 of gestation. There was no difference between the OBOV and JV for either LH or FSH, whereas the concentration of P4 in the OBOV was higher than in the JV for all periods. In both the AM and PM OBOV samples, P4 concentrations in Period 2 (AM = 83 ng/ml; PM = 67 ng/ml) were lower than Periods 1 (AM = 343 ng/ml; PM = 333 ng/ml) and 3 (AM = 534 ng/ml; PM = 305 ng/ml). However, no difference could be detected between AM (187 ng/ml) and PM (180 ng/ml) P4 concentrations when all periods were combined. Changes occurred in the concentrations and secretion patterns of P4 in the OBOV during and around the second trimester of gestation that were not reflected by P4 in the JV nor by LH and FSH in either vessel.

Immunosuppressive activity associated with early pregnancy in the bovine

Immunosuppressive activity was assessed in uterine flushings (UF) and uterine vein serum and plasma from nonpregnant and early-pregnant cows, and in media from the short-term culture of Day 18 bovine embryos. The preparations were tested for their ability to inhibit [3H] thymidine (3H-TdR) incorporation into phytohemagglutinin-stimulated bovine lymphocytes. On Days 2-3 (called Day 3), Days 9-10 (called Day 10), and Days 17-19 (called Day 18) of the estrous cycle (estrus = Day 0) and pregnancy, untreated and superovulated cows were anesthesized and jugular vein and uterine vein blood was collected. The uteri were removed and flushed to obtain UF and embryos. Uterine flushings were concentrated and tested for immunosuppressive activity at 400 micrograms uterine protein/ml culture fluid. Uterine flushings from both Day 18 pregnant and Day 18 nonpregnant cows were immunosuppressive (8/8), whereas Day 10 UF were usually not immunosuppressive (7/10). Day 3 UF were usually stimulatory or only marginally suppressive (8/8). Uterine vein serum and plasma from Day 18 cows were not suppressive when compared to jugular vein serum or plasma from the same cow; neither were Day 18 uterine vein serum or plasma suppressive when compared to those same samples taken from Day 3 cows. Embryo culture media obtained from the 48-h culture of Day 18 embryos was consistently suppressive. The activity was lost after dialysis in 1000-Mr cut-off tubing, removed by charcoal, and reduced by protease digestion. These results suggest two mechanisms whereby the embryo could escape immune rejection: 1) the progesterone-induced secretion of a uterine immunosuppressive substance(s) and 2) the production by the embryo of a low molecular weight immunosuppressive substance(s).

Prolongation of the luteal phase by prostaglandin E2 during the estrous cycle in the cow. A preliminary report

An experiment was conducted to determine the effects of prostaglandin E(2) (PGE(2)) on ovarian progesterone secretion during the estrous cycle in the cow. Intraluminal uterine catheters were implanted in three beef cows (2 treated, 1 control), and 1.3 mg of PGE(2) were infused into the uterus every 4 hours from days 9 through 21 post-estrus. Blood samples were collected from the jugular vein at 2-hour intervals from days 9 to 21 and twice daily from day 22 to 28 post-estrus. Progesterone was measured by applying a specific, direct plasma radioimmunoassay in all samples without extraction. Intrauterine infusion with PGE(2) resulted in maintenance of luteal-phase progesterone secretion until day 21 post-estrus, 4 days after luteal regression occurred in the vehicle-treated cow. In this study, we demonstrated that PGE(2) can prolong the presence of luteal phase plasma progesterone concentrations by possibly stimulating in vivo steroidogenesis by the corpus luteum during the estrous cycle in the cow.

Fetal-maternal secretion of prostaglandins in the cow

A study was conducted to measure the blood plasma concentrations of prostaglandin F2 alpha (PGF2 alpha), 13,14-dihydro-15-keto-prostaglandin F (PGFM), 6-keto-prostaglandin F1 alpha (6-keto), prostaglandin uterine artery, uterine vein, umbilical artery and umbilical vein in 24 cows from days 80 to 260 of pregnancy. Blood was collected during surgery and all prostaglandins were measured using specific radioimmunoassay procedures. Results indicate that PGF2 alpha blood levels are higher in the umbilical vessels and uterine vein than in the ovarian vein and uterine artery. PGFM and PGE2 showed a trend towards higher values in the umbilical than in the maternal vessels, but the levels of 6-keto and TBX2 were not different among the vessels studied. No differences across time could be observed in any of the prostaglandins measured, partly due to the great variability in blood levels among animals during the same stage of pregnancy.

Trenbolone, estradiol-17 beta and estrone levels in plasma and tissues and live weight gains of heifers implanted with trenbolone acetate

Twenty-four heifers were allotted into three groups of eight heifers each and designated control, long-term (LT) or short-term (ST). Animals in the latter two groups were implanted in the ear with 300 mg trenbolone acetate (TBA) for 99 or 62 d, respectively. Four heifers in each group were subjected to liver and fat biopsy 60 d after initiation of the experiment. At slaughter, which occurred 15 d after retrieval of the implant, liver and fat were also collected. The implant was analyzed for residual trenbolone (TBOH), and tissues were analyzed for TBOH and estradiol-17 beta (E2 beta). Blood samples were taken weekly after implantation and daily for 14 d before and after implantation. All heifers were weighed weekly. The ST heifers gained faster (P less than .05) than the control or the LT heifers, whereas the LT heifers gained similarly to the controls. Plasma levels of TBOH rose to over 900 pg/ml in response to the implantation in both treated groups, but stabilized at a lower level in the ST group than in the LT group. In both groups plasma E2 beta rose to over 7.5 pg/ml in response to TBA implantation; in fact, a regression analysis of E2 beta on TBOH in individual cows showed that the two hormones varied directly. Fat and liver accumulated substantial TBOH during implantation, but it cleared rapidly during the 15 d withdrawal period. Indications from this experiment are that TBA has promise for promoting rate of gain and efficiency of feed utilization in feedlot heifers. No undesirable effects on carcass quality were detected. The drug cleared blood and tissues rapidly after the implant was withdrawn. Further research is needed to determine the most effective implantation schedule. It would be desirable to determine whether a positive response to TBA will occur in animals being finished predominantly on forages.

Suckling induced cortisol secretion in young beef cows

The profiles of plasma cortisol concentration in response to suckling were determined in 10 young, postpartum beef cows between days 25 and 85 postpartum. Two trials, comprised of five cows each, were conducted in the fall (I) and spring (II), respectively. In both trials, plasma cortisol rose within 10 minutes after suckling began and was significantly higher than pre-suckling concentrations (P<.01). Over the next 30 minutes in trial I and 40 minutes in trial II, the cortisol level progressively fell back to the pre-suckling levels. This profile was qualitatively similar among the days postpartum on which the cows were bled. Neither the profile nor the peak concentration after suckling changed significantly (P>.10) as days postpartum lapsed. Finally, there was a significant difference (P<.01) in mean plasma cortisol between the cows in trial I compared to the cows in trial II.

Modulation of reproductive hormones by suckling and exogenous gonadal hormones in young beef cows post partum

Plasma concentrations of LH, prolactin, progesterone and oestradiol-17 beta were measured during post-partum anoestrus in 12 young beef cows (6 suckling, 6 not suckling). A progesterone-releasing intravaginal device (PRID) was inserted on Day 60 post partum for 12 days in 3 cows in each group. Two of three suckling cows exhibited oestrus within 2 days after PRID removal (Day 73) whereas none of the untreated cows showed oestrus before Day 93. Five of six non-suckling cows showed oestrus before Day 60. Intensive bleeding periods on Days 45, 58, 70 and 72 provided plasma samples for LH and prolactin measurements. Suckling did not affect the LH baseline or the number of LH spikes but did decrease the mean value of the spikes; all three of these characteristics were increased for prolactin. The number of prolactin spikes and the length of anoestrus in suckling cows were correlated (r = +0.87, P less than 0.05) as were mean basal LH level and length of anoestrus (r = -0.89, P less than 0.05). A decrease in plasma LH occurred in suckling and non-suckling cows during the period (Days 60-72) they were treated with gonadal hormones.

Prolactin and luteinizing hormone (LH) release throughout the postpartum period in the suckled first-calf beef cow

A study was performed to examine the release patterns of prolactin and LH of young beef cows with one (single calf) or two calves (double calf) throughout the postpartum interval. The effect on prolactin release of intramuscular and intra-carotid administration of lergotrile and intra-carotid administration of L-dopa was also examined. In approximately 50% and 65% of the cases, no prolactin release could be detected after the beginning of or during the suckling stimulus in cows with one or two calves respectively. LH plasma concentrations remained constant throughout the experiment in all animals. The chosen intramuscular lergotrile treatment lowered plasma prolactin concentrations to baseline levels but had no effect on the length of the postpartum interval. No effect on prolactin release was observed by the given intra-carotid treatments of both lergotrile and L-dopa. First postpartum estrus was observed on days 67 and 88 in the single and double calf cows respectively. The number of suckling periods did not change during the postpartum period but their duration decreased during the same period. These results demonstrate that in at least half of the cases the suckling stimulus does not cause a release of prolactin from the pituitary in the young beef cow. Also, the inhibitory effect of suckling on the resumption of ovarian cyclic function postpartum appears to be of a quantitative nature and mediated by a factor other than prolactin.

Investigations on the influence of prolactin suppression on reproductive function in bulls

In 3 mature bulls 2 injections (i.m.) of 150 mg 2-Br-alpha-ergocryptine (CB-154, Sandoz) within 48 hrs. decreased the plasma prolactin concentrations significantly for about 14 days (first experiment). In a second experiment, where treatment was repeated after 2 weeks, the period of maximal prolaction deficiency could be extended to a length of about 4 weeks. However, intensity of prolactin inhibition was less pronounced. This is attributed to seasonal factors. Neither during the shorter nor during the longer period of prolactin suppression were apparent changes of the LH and testosterone levels observed. Apart from a minor increase in the rate of morphologically abnormal sperm cells, reproductive function as libido, mating behaviour, semen quality, secretory activity of the accessory glands (concentration of fructose, GPC and chloride in seminal plasma and pre-sperm fraction resp.) were not significantly affected. It seems questionable, therefore, whether under physiological conditions prolactin is essential for the regulation of sexual functions in mature bulls.