Wildfire Induces Changes in Receiving Waters: A Review With Considerations for Water Quality Management.

Wildfires have increased in frequency in many ecosystems, with implications for human health and the environment, including water quality. Increased fire frequency and urbanization also raise the prospect of fires burning into urban areas, mobilizing pollutants few have considered to date. As a result, water quality managers lack information to anticipate, respond to and potentially mitigate wildfire impacts. Here, we reviewed the scientific literature to assess wildfire effects on response endpoints of a conceptual model linking fire to water quality, quantifying response directionality, magnitude and duration. Physically, water yield, sediments, and temperature all increased post-fire. Chemically, nutrients, ions, organic chemicals, and metals increased in burned watersheds, sometimes by orders of magnitude over pre-fire or reference conditions. In select cases, post-fire concentrations exceeded aquatic life criteria or drinking water standards, at times even in the finished drinking water. Biological assemblages commonly declined after post-fire runoff events. The duration of effects was less than 5 yr for most endpoints (e.g., metals) on average following fire, although effects did extend 15 yr or more in some individual cases. We found only a few studies on pollutants mobilized from wildfire impacted urban areas with benzene contamination in drinking water and high metal concentrations in ash prominent exceptions. Overall, this review provides a resource for understanding wildfire impacts on water quality endpoints, with the goal of informing the response of managers and other decision makers to this growing problem.

A catalyst for transforming health systems and person-centred care: Canadian national position statement on patient-reported outcomes.

Background: Patient-reported outcomes (pros) are essential to capture the patient's perspective and to influence care. Although pros and pro measures are known to have many important benefits, they are not consistently being used and there is there no Canadian pros oversight. The Position Statement presented here is the first step toward supporting the implementation of pros in the Canadian health care setting. Methods: The Canadian pros National Steering Committee drafted position statements, which were submitted for stakeholder feedback before, during, and after the first National Canadian Patient Reported Outcomes (canpros) scientific conference, 14-15 November 2019 in Calgary, Alberta. In addition to the stakeholder feedback cycle, a patient advocate group submitted a section to capture the patient voice. Results: The canpros Position Statement is an outcome of the 2019 canpros scientific conference, with an oncology focus. The Position Statement is categorized into 6 sections covering 4 theme areas: Patient and Families, Health Policy, Clinical Implementation, and Research. The patient voice perfectly mirrors the recommendations that the experts reached by consensus and provides an overriding impetus for the use of pros in health care. Conclusions: Although our vision of pros transforming the health care system to be more patient-centred is still aspirational, the Position Statement presented here takes a first step toward providing recommendations in key areas to align Canadian efforts. The Position Statement is directed toward a health policy audience; future iterations will target other audiences, including researchers, clinicians, and patients. Our intent is that future versions will broaden the focus to include chronic diseases beyond cancer.

Feasibility of a tapering opioids prescription program for trauma patients at high risk of chronic consumption (TOPP-trauma): protocol for a pilot randomized controlled trial.

BACKGROUND: Opioid use disorder (OUD) and deaths related to the chronic use of opioids have increased significantly over the last two decades. Chronic consumption of opioids has been documented in many patients with traumatic injuries. Preliminary research findings have shown that interventions using cognitive-behavioral strategies were a promising adjunct in decreasing the burden associated with opioid consumption. Accordingly, the Tapering Opioids Prescription Program in Trauma (TOPP-Trauma) was developed. PURPOSE: To assess the feasibility of the TOPP-Trauma intervention and its research methods; and explore the potential efficacy of TOPP-Trauma in reducing opioid consumption. METHODS: A 2-arm pilot randomized controlled trial (RCT) will be conducted in patients presenting a high risk for chronic opioid consumption. Fifty participants at high risk for chronic consumption of opioid will receive either TOPP-Trauma or an educational pamphlet. The feasibility assessment of TOPP-Trauma will be based on the ability to provide its components as initially planned. Several parameters will be evaluated to determine the feasibility of the research methods, including the adequacy of the sampling pool, the dropout rate, and the ease of data collection. The morphine equivalent dose (MED) per day between both groups will be measured at 6 and 12 weeks. Pain intensity and pain interference with activities will also be evaluated at the same time points. DISCUSSION: This study will provide evidence on the feasibility of a preventive program aimed at reducing chronic opioid use in high risk trauma patients. Information will also be gathered on the methods that should be used to test the efficacy of such programs. TRIAL REGISTRATION: International Standard Randomized Controlled Trial Number (ISRCTN): 40263056. Registered 26 May 2018.

Clinical impact of positive Propionibacterium acnes cultures in orthopedic surgery.

BACKGROUND: The clinical significance of a positive culture to Propionibacterium acnes in orthopedic specimens remains unclear, whether about its role as a contaminant or a pathogen, or its impact as a coinfectant. Therefore, we performed a retrospective study to provide a more accurate description of the clinical impact of P. acnes in an orthopedic population aiming to determine: 1) if there is a clinical difference between P. acnes infection and contamination? 2) If there is a clinical difference between P. acnes monoinfection, and coinfection. HYPOTHESIS: There is a clinical difference between P. acnes infection and contamination. MATERIALS AND METHODS: Patients were selected over a five-year period, and those with a minimum of one positive culture for P. acnes, from any intraoperative orthopedic tissue sample, were included in the study. P. acnes infection was defined as the isolation of P. acnes from≥2 specimens, or in only one specimen, in the presence of typical perioperative findings and/or local signs of infection. RESULTS: A total of 68 patients had a positive P. acnes culture, 35 of which were considered to be infected. The infections affected mostly males (29/35-83%), occurred mostly in shoulders (22/35-63%), and at a site already containing an orthopedic implant (32/35-91%). Local inflammatory signs were present in half of the cases when an infection was diagnosed. Coinfection with other pathogens was present in 31% of patients (11/35). When comparing patients coinfected with P. acnes, and those who were monoinfected, the latter presented less often with local inflammatory signs. Recurrence rate was 24% (8/35) and the only risk factor for recurrence was the presence of a monoinfection. DISCUSSION: This study confirms the pathogenicity of P. acnes in an orthopedic population, as it is present in multiple samples in the same patient, and because it is present in cultures from cases with clinical recurrence. Our study showed that monoinfections differ from coinfections mainly by their higher risk of recurrence. LEVEL OF EVIDENCE: Level IV retrospective case series.

The impact of a standardized order set for the management of non-hip fragility fractures in a Fracture Liaison Service.

We analysed the impact of a standardized order set empowering staff nurses to independently manage a Fracture Liaison Service over a 9-month period. Nurses identified between 30 and 70 % of non-hip fragility fractures to the unit in charge of management over time. The latter managed 58 % of referred patients. INTRODUCTION: The main goal of this study was to evaluate the impact of a standardized order set empowering nurses to independently manage a fracture liaison service (FLS). METHODS: Since November 2014, an order set allowed nurses of a Montreal hospital, Quebec, Canada to entirely manage an FLS on their own. Nurses followed an 6-h training program on-site. Emergency department (ED) and orthopaedic outpatient clinic (OC) nurses identified non-hip fragility fractures. Medical day treatment unit (MDTU) nurses were in charge of the management (investigation and treatment initiation). The list of patients, 50 years and older, with a fracture were retrieved for the period of November 2014 to July 2015. Performance was assessed with the rate of identification over time and the rate of management of non-hip fragility fractures. RESULTS: Over the 9-month period, 346 patients of ≥50 years old were seen for a fracture, of which 190 met fragility criteria (excluding hip fractures). A sinusoid pattern of rates of identification between 30-70 % was observed over time. An average proportion of 58.1 % of fracture patients were managed by MDTU nurses. CONCLUSIONS: A standardized order set legally allowing nurses to manage an FLS led to identification rates varying from 30-70 % and a management rate close to 60 % for referred patients over a 9-month period, which largely exceeds that of standard care. Identification was mostly compromised by difficulty integrating the order set into routine practice. Enforcement of the hospital policy on fragility fractures could help yield efficiency of identification of osteoporosis-related fractures by the staff.

Logistic analysis of algae cultivation.

Energy requirements for resource transport of algae cultivation are unknown. This work describes the quantitative analysis of energy requirements for water and CO2 transport. Algae cultivation models were combined with the quantitative logistic decision model 'BeWhere' for the regions Benelux (Northwest Europe), southern France and Sahara. For photobioreactors, the energy consumed for transport of water and CO2 turns out to be a small percentage of the energy contained in the algae biomass (0.1-3.6%). For raceway ponds the share for transport is higher (0.7-38.5%). The energy consumption for transport is the lowest in the Benelux due to good availability of both water and CO2. Analysing transport logistics is still important, despite the low energy consumption for transport. The results demonstrate that resource requirements, resource distribution and availability and transport networks have a profound effect on the location choices for algae cultivation.

A summary of the Transfusion Error Surveillance System: 2008 - 2011.

BACKGROUND: Although Canada has one of the safest blood systems in the world, transfusion errors can occur at any time from the moment of collection through to the transfusion of blood and blood products. The Transfusion Error Surveillance System (TESS) was initiated by the Public Health Agency of Canada (the Agency) to monitor transfusion-related errors occurring at any point in the transfusion chain. OBJECTIVE: To offer an analysis of the TESS data reported from 2008 to 2011. METHODS: Between 2008 and 2011, 12 to 15 hospitals from four provinces participated in the TESS. Reports on all transfusion-related errors were sent electronically on a quarterly basis to the Agency where they were consolidated, cleaned, validated and analyzed. Different types of transfusion errors were categorized by time of discovery (pre- or post-transfusion) and their potential impact on the patient's health. The occurrence rates of different types of errors were calculated using corresponding denominator data. Results were grouped by the transfusion capacity of reporting hospitals. RESULTS: Between 2008 and 2011, a total of 34,088 transfusion-related errors were reported. Of these, 33,622 (98.6%) were detected prior to transfusion. The most commonly reported were errors related to the collection (40.1%) and handling (10.4%) of blood samples. Of the remaining 466 (1.4%) that were detected after transfusion, 66 were of high potential severity and 16 of them resulted in adverse reactions in recipients. Inappropriate / incorrect / no product order accounted for over 56% (n=9) of these errors and the most common adverse reaction was transfusion-associated circulatory overload which occurred in eight (50%) of the patients that developed adverse reactions. CONCLUSION: The TESS data from 2008 to 2011 demonstrates that blood transfusions are both safe and efficient in Canadian hospitals participating in the surveillance and also highlights the most common and most harmful errors that may be targeted for corrective actions.

A summary of the Transfusion Transmitted Injuries Surveillance System: 2006 - 2012.

BACKGROUND: The Transfusion Transmitted Injuries Surveillance System (TTISS) is a pan-Canadian surveillance system established by the Public Health Agency of Canada (the Agency) in partnership with the provinces and territories to capture non-nominal data on adverse transfusion reactions in Canadian hospitals providing transfusion services with the overarching goal of improving patient safety. OBJECTIVE: To summarize transfusion-related adverse reactions reported to the TTISS between 2006 and 2012. METHODS: Hospitals from 10 provinces and two territories participated in the TTISS by collecting and submitting data on all transfusion-related reactions or injuries to the provincial / territorial blood coordinating offices. This data was sent to the Agency where it was consolidated, cleaned, validated and analyzed by type of reactions or outcome. Corresponding rates were also calculated using the total number of units of blood components transfused as a denominator. RESULTS: From 2006 to 2012, a total of 3,957 adverse reactions were reported to the TTISS, excluding minor allergic reactions. Of these, 2,920 (73.8%) were related to transfusion of blood components and 1,036 (26.2%) were from the transfusion of blood products. Among reactions related to the transfusion of blood components, the most common were: transfusion-associated circulatory overload (n = 1,242, 42.5%), severe allergic / anaphylactic / anaphylactoid reactions (n=411; 14.1%) and hypotensive reactions (n=298; 10.2%). Among those related to transfusion of blood products, close to one-half were intravenous immunoglobulin (IVIG) headache (n=295; 28.5%) or delayed hemolytic reaction (n=175; 16.9%). Death definitely attributable to transfusion was extremely rare: only one case diagnosed with transfusion-related acute lung injury was identified between 2006 and 2012. CONCLUSION: The majority of reactions attributable to transfusion resulted in minor or no sequelae. Strengthening the TTISS will improve the monitoring of adverse transfusion reactions which is one of the key components of an overall patient safety strategy. Current initiatives to improve data quality include the development of transfusion-associated circulatory overload / transfusion-related acute lung injury recognition algorithm and the collection of appropriate denominators for the calculation of the rates of adverse reactions from the transfusion of blood products.

Lack of involvement of type 7 phosphodiesterase in an experimental model of asthma.

Type 7 phosphodiesterases (PDE7) are responsible for the decrease of intracellular cyclic AMP (cAMP) in many cells involved in allergic asthma by suppressing their potential to respond to many activating stimuli. The elevation of intracellular cAMP has been associated with immunosuppressive and anti-inflammatory activities and represents a potential treatment of asthma. Our aim was to evaluate the impact of the deletion of the murine phosphodiesterase (PDE)7B gene and then to evaluate the efficacy of a newly described selective PDE7A and -B inhibitor on an ovalbumin (OVA)-induced airway inflammation and airway hyperreactivity (AHR) model in mice. Inflammation was determined 72 h after single OVA challenge or 24 h after multiple challenges by the relative cell influx and cytokine content in bronchoalveolar lavage fluid. AHR and immunoglobulin E levels in serum were determined after multiple challenges. For the first time, we have demonstrated that the deletion of the PDE7B gene or the pharmacological inhibition of PDE7A and -B had no effect on all the parameters looked at in this model. These results highlight the absence of any implication of the PDE7 enzyme in our model.

Internal fixation of osteopenic acetabular fractures involving the quadrilateral plate.

BACKGROUND: Older patients tend to have acetabular fractures with medial displacement patterns and associated comminution, particularly of the quadrilateral surface. Our goal was to investigate the appropriateness of open reduction and internal fixation using an infra-pectineal buttress plate for osteopenic acetabular fractures. MATERIALS AND METHOD: We conducted a retrospective review involving twenty one consecutive patients over the course of 4 years with an acetabular fracture in an academic level 1 trauma centre. We performed the modified Stoppa approach with buttress plating of the quadrilateral surface. Clinical examination radiographs was done using criteria described by Matta. Functional outcome was evaluated using surveys including SF-12, WOMAC, Harris Hip score and modified Postel Merle D'Aubigne. RESULTS: Average follow-up was 4.2 years with a minimum of 2 years. Mean age for patients was 64.3 years. We obtained anatomic reduction in 52.4% (11/21) of cases, imperfect reduction in 38.1% (8/21) of cases and poor reduction in 9.5% (2/21) of cases. Significant loss of reduction was seen in 2 patients. A superior dome impaction (a Gull sign) was correlated to arthroplasty (p=0.02) and reduced quality of initial reduction (p=0.02). Two patients required re-intervention with a total hip arthroplasty. There was one traumatic injury to the obturator nerve and 2 patients were noted to have temporary weakness of the hip adductors postoperatively. CONCLUSION: Internal fixation using the modified Stoppa approach to buttress the quadrilateral plate should be considered a viable alternative to total hip arthroplasty for the initial treatment of acetabular fractures in the elderly.

A randomised clinical trial comparing minimally invasive surgery to conventional approach for endoprosthesis in elderly patients with hip fractures.

BACKGROUND: In recent years, the concept of minimally invasive surgery has invaded the orthopaedic field and literature on the subject is spawning. Mini-incision surgery for total hip arthroplasty has been studied without a clear consensus on the efficacy, safety and advantage of that technique. To our knowledge, the efficacy and safety of mini-incisions in hip fracture surgery has not been studied in a randomised fashion. METHODS: This study is a prospective clinically randomised trial whose primary objective was to demonstrate the safety and efficacy of a single posterior mini-incision approach compared to a standard posterior approach for endoprosthesis in acute femoral neck fractures. The mini-incision was defined as less than 8 cm. 25 patients in the mini-incision surgery (MIS) group and 31 patients in the standard incision group (STD) were available for analysis. The following validated disease-specific outcome instruments were used: the Lower Extremity Measurement (LEM) and the Time Up and Go (TUG). Secondary endpoints of pain, function, and quality of life were assessed by the components of the Harris Hip Score (HHS) and SF-36. Radiographic outcomes were also evaluated as well as the rates of all reported complications and adverse events during the 2 years follow-up. RESULTS: There was no significant difference for operative time, blood losses, 72 h postoperative haemoglobin as well as the need for transfusion therapy between the two groups. Also, there was no difference between the groups for postoperative morphine use and pain evaluation with the Visual Analog Scale. The functional assessment using LEM and TUG did not demonstrate any statistically significant difference between mini- and standard incision. However, the HHS and the physical function component of the SF-36 were statistically better at 2 years in favour of the standard incision group. CONCLUSION: Based on the results of the present study, we cannot recommend the use of a minimally invasive approach over a standard approach in the implantation of a cemented endoprosthesis.

Lateral compression fractures of the superior pubic ramus with intra-articular extension.

A total of 30 patients with lateral compression fractures of the pelvis with intra-articular extension into the anterior column were followed for a mean of 4.2 years (2 to 6), using the validated functional outcome tools of the musculoskeletal function assessment and the short-form health survey (SF-36). The functional outcome was compared with that of a series of patients who had sustained type-B1 and type-C pelvic fractures. The lateral-compression group included 20 men and ten women with a mean age of 42.7 years (13 to 84) at the time of injury. Functional deficits were noted for the mental component summary score (p = 0.008) and in the social function domain (p < 0.05) of the SF-36. There was no evidence of degenerative arthritis in the lateral-compression group. However, they had high functional morbidity including greater emotional and psychological distress.

Folate requirements of the 2-keto-L-gulonic acid-producing strain Ketogulonigenium vulgare LMP P-20356 in L-sorbose/CSL medium.

In this study, the requirements for growth factors of Ketogulonigenium vulgare LMP P-20356, a 2-keto-L-gulonic acid-producing strain of particular interest for the manufacture of vitamin C, were assessed. Various growth factors were studied in order to obtain improved growth of the strain when cultured in an L-sorbose/corn steep liquor medium. Cultures grown in the presence of reduced mono- and polyglutamated folate derivatives showed a 15- to 20-fold higher biomass content than control cultures lacking these supplements, indicating that the strain has a requirement for folate. Although most folate derivatives used in this study promoted growth, the amplitude of the response varied depending on the compound used. Dihydrofolic acid was found to be the most active form, followed by 5-formyltetrahydrofolic acid, 5-methyltetrahydrofolic acid and tetrahydrofolic acid. Folic acid had no effect. The effectiveness of polyglutamated derivatives was inversely proportional to the polyglutamated chain-length of the derivative used. Our results suggest that the rate-limiting step in the utilisation of monoglutamated folates is most probably related to their transport and/or their intracellular interconversion rather than their polymerisation into polyglutamated forms (physiological forms). The industrial production of 2-keto-L-gulonic acid by K. vulgare LMP P-20356 could be improved by using media in which low-molecular-weight reduced folates are present.

Home delivery of an injury prevention kit for children in four French cities: a controlled randomized trial.

OBJECTIVES: Home delivery of counselling and safety devices to prevent child injuries could help parents to adopt safe behaviour. The aim of this study was to test a safety kit designed and used in Quebec (Canada). DESIGN AND SUBJECTS: One hundred families from four towns in the Paris suburbs were visited at home by nurses or doctors when their child reached 6-9 months. Selection criteria were: primipara, medical problem, psychological, and/or socioeconomic difficulties. INTERVENTIONS: During the first visit, 50 families (group 1) received counselling and a kit including preventive devices and pamphlets about indoor injuries and ways to avoid them. The other 50 families (group 2) received counselling but not the kit. A second home visit was made 6-8 weeks later. MAIN OUTCOME MEASURES: The number of safety improvements was calculated 6-8 weeks after a first home visit. Perceived usefulness of the kit was collected from families and from interviewers. RESULTS: Between the first and the second visits, safety improvement was significantly higher in the group with the kit. This was mainly related to the risk of fall (p<0.02), fire and burns (p<0.001), poisoning (p<0.01), and suffocation (p<0.001). For improvement related to devices provided in the kit, the difference between the groups was significant: 64.4% improvement in group 1 versus 41.2% in group 2 (p<0.01). The relative risk (RR) of safety improvement between groups was 1.56 (95% confidence interval (CI) 1.35 to 1.80). Even for improvements not related to the kit the difference remained significant: 31.2% in group 1 versus 20.2% in group 2 (p<0.05); RR = 1.54 (95% CI 1.22 to 1.93). CONCLUSION: Routine home visits by social services offer a good opportunity to tackle child injury prevention. Free delivery of prevention kits and counselling allow families to modify their behaviour and homes so as to reduce risks.

Quantitative assessment of articular cartilage and subchondral bone histology in the meniscectomized guinea pig model of osteoarthritis.

OBJECTIVE: A new image analysis system was employed to quantify the main histological parameters reflecting osteoarthritic features, at the cartilage and bone levels, in the meniscectomized guinea pig model of osteoarthritis (OA). METHODS: Meniscectomized (MNX) and sham-operated (SH) guinea pigs were studied 1 and 3 months after partial meniscectomy at the medial side of the left knee (n=10 to 12 animals/group). The left proximal tibias were included in methylmethacrylate. Sections were cut and stained with safranin O or Goldner trichrome. Parameters were quantified using special programs of a Biocom image analyser. The following parameters were evaluated at the medial side of the tibia: cartilage thickness (CT); fibrillation index (FI); proteoglycan content ratio based on safranin O staining intensities (PC); chondrocyte density (CD); bone volume (BV) and subchondral bone plate thickness (SBPT). The degree of user interaction varied from manually tracing objects to almost complete computer automation. RESULTS: Meniscectomy resulted in significant variations of these reproducible histomorphometric parameters both after 1 month (FI: +522%, P<0.01) and 3 months (FI: +162%, P<0.001; PC: -36.7%, P<0.001; CD: -31.8%, P<0.001; SBPT: +8.7%, P<0.05) post-operation (results expressed as percentage variation of MNX vs SH). The linear correlation analysis including data from SH and/or MNX animals at the two grouped time points revealed significant r values, in particular between cartilage (CT) and subchondral bone parameters (SBPT) (r=-0.41, P<0.01). CONCLUSIONS: Contrary to scoring evaluation, this system allowed to show the time-dependent impact of the pathology with an early fibrillation of the medial tibial cartilage appearing as soon as 1 month post-surgery, and the close relationship between bone and cartilage parameters during the progression of OA.

Reductive cleavage of demeton-S-methyl by Corynebacterium glutamicum in cometabolism on more readily metabolizable substrates.

Corynebacterium glutamicum is able to biotransform demeton-S-methyl, an organophosphorus compound, during cometabolism with more readily metabolizable substrates. Among the cosubstrates used, fructose is the growth substrate that is most favorable for demeton-S-methyl biotransformation. The reaction mechanism of demeton-S-methyl biotransformation involves reductive cleavage of an S-C bond, which leads to accumulation of dimethyl thiophosphate in the culture medium.

[Mechanical evaluation of a ligament fixation system for ACL reconstruction at the tibia in a canine cadaver model]. / Evaluation mécanique d'un système de fixation ligamentaire pour la reconstruction du LCA au niveau du tibia sur un modèle canin cadavérique.

OBJECT: Excellent fixation of an artificial ligament in bone is mandatory for initial stability. ACL reconstruction with the LARS artificial ligament may fail if anchorage to bone is inadequate. The weak metaphyseal bone of the proximal tibia is prone to inadequate fixation. This study evaluates the initial mechanical stability of two techniques with an interference screw on the tibial side of an ACL reconstruction with the LARS ligament. METHODS: Six left tibias were obtained from 1 to 3 year old mongrel dog weighing 20 to 26 kg. ACL straight line reconstruction according to the technique described by J.P. Laboureau was performed with a 4.5 mm drill. Two tunnels were created in the tibia, one oblique and one transverse, the latter 2 cm below the former. Reconstruction was done with a 30-fiber LARS ligament and a 5.2 mm x 15 mm conical titanium cannulated interference screw. Group I had an interference screw in the oblique tunnel and group II had an interference screw in the transverse tunnel. Pull-out tests were performed parallel to the oblique tunnel on an Instron 8521 machine at a speed of 5 mm per minute until failure. The oblique tunnel was tested first then the transverse tunnel. RESULTS: Group I (n = 6): sliding value = 238 +/- 115 N. Group II (n = 6): sliding value = 998 +/- 148 N. This is statistically significant (p < 0.001, student t-test). CONCLUSION: One interference screw in a transverse tibial tunnel for ACL reconstruction with the LARS ligament is 4 times more resistant on loading and impact than an oblique screw.

Steroid synthesis by equine conceptuses between days 7 and 14 and endometrial steroid metabolism.

The objective of this study was to determine if changes in steroid synthesis occurred in the horse blastocyst about the time of maternal recognition of pregnancy. Embryos collected between days 7.5 and 14.5 were incubated for 8 hr in vitro in HAM's F10 containing radiolabelled pregnenolone. The steroid metabolites in the incubation medium were separated by reverse phase HPLC and the major peaks expressed as a percentage of total metabolites. It was found that there were no major changes in the profile of metabolites throughout the period of study, although there was increased conversion as the conceptuses developed. It was found that the major metabolite produced was 17 alpha-hydroxyprogesterone and not estradiol as expected. A second experiment was conducted to determine if 17 alpha-hydroxyprogesterone was metabolized by endometrial tissue. Endometrial biopsies from anestrous mares and from pregnant and nonpregnant mares at day 11 were incubated with radiolabelled 17 alpha-hydroxyprogesterone, progesterone or pregnenolone. The 17 alpha-hydroxyprogesterone, but not progesterone nor pregnenolone, was converted to a more polar metabolite in all groups. Production of this metabolite was significant greater in the anestrous mares. This metabolite has not been unidentified conclusively. Thus, results of this study show that 17 alpha-hydroxyprogesterone is the major steroid synthesized by the equine blastocyst and that this steroid is further metabolized to an unidentified steroid by the endometrium. These steroids could play a role in conceptus development or maternal recognition of pregnancy.