Quality of life and functional outcomes following pelvic exenteration and sacrectomy.

AIM: The aim was to compare postoperative quality of life (QOL) between patients undergoing pelvic exenteration (PE) and pelvic exenteration with sacrectomy (PES), and to investigate the influence of high (L5-S2) vs low (≤ S3) sacrectomy on QOL and functional outcomes. METHOD: Patients undergoing en bloc sacrectomy as part of a PE and PE alone from 2008 to 2015 were identified from a prospectively maintained database. QOL and functional outcomes were assessed using the 36-Item Short Form Survey, the European Organization for Research and Treatment of Cancer Colorectal Cancer questionnaire and Quality of Life questionnaire, the Revised Musculoskeletal Tumour Scale, the Lower Extremity Functional Scale, the Sexual Health Inventory for Men and the Female Sexual Function Index. RESULTS: Of the 344 patients identified, data were available for 116 patients who underwent PE alone and 140 patients who underwent PES. PES patients had significantly poorer physical component scores (P < 0.001) but not mental component scores (P = 0.17). Of the 140 PES patients, 55 were eligible and were invited to participate in a second functional survey, with 30 patients returning the study questionnaire. High sacrectomy patients, compared with low sacrectomy, had significantly worse lower limb motor function (P = 0.03) and poorer physical (P = 0.001) and mental health component scores (P = 0.02). No differences were found in sexual, bladder and bowel function between high and low sacrectomy patients. CONCLUSIONS: Patients undergoing PES had worse physical component scores compared with PE alone, whereas high sacrectomy patients had significantly worse lower limb motor function and physical and mental component scores but comparable bowel, bladder and sexual functional outcomes compared with low sacrectomy patients.

Validation of a biomarker panel in Barrett's esophagus to predict progression to esophageal adenocarcinoma.

In a prior study, baseline mutational load (ML) predicted progression to high-grade dysplasia (HGD) or esophageal adenocarcinoma (EAC) in Barrett's esophagus (BE) with an area under the curve (AUC) of 0.95. We aimed to validate the test characteristics of this predictive biomarker panel using crude DNA lysates in a larger well-characterized cohort. We performed a nested case-control study of BE patients from three tertiary referral centers in the Netherlands. Cases had baseline nondysplastic BE (NDBE) and developed HGD/EAC ≥ 2 years later. Controls were matched 2:1, had baseline NDBE, and no progression. Polymerase chain reaction (PCR)-based mutational analysis was performed on crude lysates from formalin-fixed, paraffin-embedded tissue. ML was calculated from loss of heterozygosity (LOH) and microsatellite instability (MSI) at 10 genomic loci. Receiver operator characteristic (ROC) curves were created to assess the diagnostic utility of various cutoffs of ML for progression. Of 159 subjects, 58 were progressors and 101 were nonprogressors, there was no difference in mean ML in preprogression tissue in progressors and nonprogressors (ML = 0.73 ± 0.69 vs. ML = 0.74 ± 0.61, P = 0.93). ROC curves showed poor discrimination of ML in predicting progression with AUC of 0.50 at ML ≥ 1. AUC did not vary with different ML cut-points. The utility of the ML to stratify BE patients for risk of progression was not confirmed in this study. The etiology for discrepancies between this and prior studies showing high predictiveness is likely due to the use of crude lysates in this study, but requires further investigation.

The Pathogen-annotated Tracking Resource Network (PATRN) system: a web-based resource to aid food safety, regulatory science, and investigations of foodborne pathogens and disease.

Investigation of foodborne diseases requires the capture and analysis of time-sensitive information on microbial pathogens that is derived from multiple analytical methods and sources. The web-based Pathogen-annotated Tracking Resource Network (PATRN) system (www.patrn.net) was developed to address the data aggregation, analysis, and communication needs important to the global food safety community for the investigation of foodborne disease. PATRN incorporates a standard vocabulary for describing isolate metadata and provides a representational schema for a prototypic data exchange standard using a novel data loading wizard for aggregation of assay and attribution information. PATRN currently houses expert-curated, high-quality "foundational datasets" consisting of published experimental results from conventional assays and next generation analysis platforms for isolates of Escherichia coli, Listeria monocytogenes, and Salmonella, Shigella, Vibrio and Cronobacter species. A suite of computational tools for data mining, clustering, and graphical representation is available. Within PATRN, the public curated data repository is complemented by a secure private workspace for user-driven analyses, and for sharing data among collaborators. To demonstrate the data curation, loading wizard features, and analytical capabilities of PATRN, three use-case scenarios are presented. Use-case scenario one is a comparison of the distribution and prevalence of plasmid-encoded virulence factor genes among 249 Cronobacter strains with similar attributes to that of nine Cronobacter isolates from recent cases obtained between March and October, 2010-2011. To highlight PATRN's data management and trend finding tools, analysis of datasets, stored in PATRN as part of an ongoing surveillance project to identify the predominant molecular serogroups among Cronobacter sakazakii isolates observed in the USA is shown. Use-case scenario two demonstrates the secure workspace available for private users to upload and analyze sensitive data, and for collating cross-platform datasets to identify and validate congruent datapoints. SNP datasets from WGS assemblies and pan-genome microarrays are analyzed in a combinatorial fashion to determine relatedness of 33 Salmonella enterica strains to six strains collected as part of an outbreak investigation. Use-case scenario three utilizes published surveillance results that describe the incidence and sources of O157:H7 E. coli isolates associated with a produce pre-harvest surveillance study that occurred during 2002-2006. In summary, PATRN is a web-based integrated platform containing tools for the management, analysis and visualization of data about foodborne pathogens.

Flow and outdoor adventure recreation: Using flow measures to re-examine motives for participation.

Adventure participants have traditionally been viewed as having thrill or risk-seeking motives, and this perception remains despite empirical research suggesting that other motives may drive participation. This study was conducted to extend understanding of participation motives of adventure recreation participants in relation to Csiksentmihalyi's nine-dimension model of flow and other proposed motivational constructs. Participants (n = 199) who had typically engaged in their adventure recreation activity (i.e., highlining, rock climbing, downhill mountain biking, freefalling, snow sports) regularly, and with considerable competence, took part in this investigation by completing self-report measures of dispositional flow (The Dispositional Flow Scale; DFS-2), state flow (The Short Flow State Scale; SFSS), and participation motives in their adventure recreation environments. Support was observed in confirmatory factor analytic procedures for the factorial validity of DFS-2 and SFSS data obtained from adventure recreation participants. Mean scores from measures on participant experience of flow in adventure recreation were generally found to be significantly higher than previously observed in other physical activity domains, with some differences also being observed among adventure recreation subgroups. Contrary to traditional explanations of adventure recreation participation, risk-seeking was not supported as a key underlying motive by participants in this study. Mastery of one's adventure recreation activity, perceived connection to one's activity, and trust in one's skills, were identified as important participation motives. This study demonstrated that the DFS-2 and SFSS were able to satisfactorily assess flow constructs in adventure recreation, and supported recent research demonstrating flow to be a relevant experience to this setting. The implications of these findings for theory, practice, and future research directions in adventure recreation are discussed.

Imaging features of ductal plate malformations in adults.

Ductal plate malformations, also known as fibrocystic liver diseases, are a group of congenital disorders resulting from abnormal embryogenesis of the biliary ductal system. The abnormalities include choledochal cyst, Caroli's disease and Caroli's syndrome, adult autosomal dominant polycystic liver disease, and biliary hamartoma. The hepatic lesions can be associated with renal anomalies such as autosomal recessive polycystic kidney disease (ARPKD), medullary sponge kidney, and nephronophthisis. A clear knowledge of the embryology and pathogenesis of the ductal plate is central to the understanding of the characteristic imaging appearances of these complex disorders. Accurate diagnosis of ductal plate malformations is important to direct appropriate clinical management and prevent misdiagnosis.

Clinical characteristics of patients with premature lower extremity atherosclerosis associated with familial early cardiovascular disease and/or cancer.

AIM: In the past decade we experienced a steady growth in the number of young smokers with severe premature lower extremity atherosclerosis (PLEA) and high frequency of familial cardiovascular disease (Fam CVD). The widely used Framingham risk score does not include Fam CVD among predictors of incident CVD. METHODS: We studied 370 patients younger than 55 with severe PLEA (45% females, 96% smokers) treated between 1998 and 2004. Overall, 312 (85%) patients reported a positive history of Fam CVD; 217 (59%) had family history of premature CVD (FamP-CVD), and 29% had history of early malignancies in family members <60 years (Fam Mal <60). RESULTS: Patients with FamP-CVD compared to those without FamP-CVD had similar prevalence of traditional risk factors, and concentrations of metabolic and inflammatory parameters, however had greater prevalence of clinical coronary artery disease (P=0.03), cerebrovascular disease (P=or<0.01) or both (P<0.01). Patients with both FamP-CVD and Fam Mal <60 (n=58) when compared to those with neither (n=92), had greater frequency of dyslipidemia (P=0.02) and coronary revascularizations (P=0.02). Patients with Fam P-CVD had 3-fold higher odds of prevalent CVD compared to those without Fam P-CVD. This association was independent of demographic and cardiovascular risks. CONCLUSIONS: In patients with PLEA, familial premature CVD may predict early clinical manifestations of systemic atherosclerosis, independently of traditional risk factors. Patients with family history of early malignancies had similar clinical characteristics, including prevalence of CVD.

Effects of carbohydrates on membrane stability at low water activities.

The relative effectiveness of a variety of carbohydrates in preserving the structural and functional integrity of membranes at low water activities was studied, using Ca-transporting microsomes from muscle as a model membrane. The order of effectiveness (greatest to lowest) was: trehalose, lactose, maltose, cellobiose, sucrose, glucose, fructose, sorbitol, raffinose, myo-inositol, glycerol. At the highest concentrations of the most effective sugars tested, microsomes were obtained upon rehydration that were similar structurally and functionally to fresh membranes. The least effective carbohydrates, alcohol sugars, all appear to be fusogenic. A structural explanation for relative effectiveness of the sugars was sought, but no clear relationship was found, except that effectiveness does not appear to be related to the number of position of hydroxyl groups available for hydrogen bonding.

High-resolution fine mapping and fluorescence in situ hybridization analysis of sun, a locus controlling tomato fruit shape, reveals a region of the tomato genome prone to DNA rearrangements.

The locus sun on the short arm of tomato chromosome 7 controls morphology of the fruit. Alleles from wild relatives impart a round shape, while alleles from certain cultivated varieties impart an oval shape typical of roma-type tomatoes. We fine mapped the locus in two populations and investigated the genome organization of the region spanning and flanking sun. The first high-resolution genetic map of the sun locus was constructed using a nearly isogenic F(2) population derived from a cross between Lycopersicon pennellii introgression line IL7-4 and L. esculentum cv Sun1642. The mapping combined with results from pachytene FISH experiments demonstrated that the top of chromosome 7 is inverted in L. pennellii accession LA716. sun was located close to the chromosomal breakpoint and within the inversion, thereby precluding map-based cloning of the gene using this population. The fruit-shape locus was subsequently fine mapped in a population derived from a cross between L. esculentum Sun1642 and L. pimpinellifolium LA1589. Chromosome walking using clones identified from several large genomic insert libraries resulted in two noncontiguous contigs flanking sun. Fiber-FISH analysis showed that distance between the two contigs measured 68 kb in L. esculentum Sun1642 and 38 kb in L. pimpinellifolium LA1589, respectively. The sun locus mapped between the two contigs, suggesting that allelic variation at this locus may be due to an insertion/deletion event. The results demonstrate that sun is located in a highly dynamic region of the tomato genome.

Retrotransposon-related DNA sequences in the centromeres of grass chromosomes.

Several distinct DNA fragments were subcloned from a sorghum (Sorghum bicolor) bacterial artificial chromosome clone 13I16 that was derived from a centromere. Three fragments showed significant sequence identity to either Ty3/gypsy- or Ty1/copia-like retrotransposons. Fluorescence in situ hybridization (FISH) analysis revealed that the Ty1/copia-related DNA sequences are not specific to the centromeric regions. However, the Ty3/gypsy-related sequences were present exclusively in the centromeres of all sorghum chromosomes. FISH and gel-blot hybridization showed that these sequences are also conserved in the centromeric regions of all species within Gramineae. Thus, we report a new retrotransposon that is conserved in specific chromosomal regions of distantly related eukaryotic species. We propose that the Ty3/gypsy-like retrotransposons in the grass centromeres may be ancient insertions and are likely to have been amplified during centromere evolution. The possible role of centromeric retrotransposons in plant centromere function is discussed.

Comparative fluorescence in situ hybridization mapping of a 431-kb Arabidopsis thaliana bacterial artificial chromosome contig reveals the role of chromosomal duplications in the expansion of the Brassica rapa genome.

Comparative genome studies are important contributors to our understanding of genome evolution. Most comparative genome studies in plants have been based on genetic mapping of homologous DNA loci in different genomes. Large-scale comparative physical mapping has been hindered by the lack of efficient and affordable techniques. We report here the adaptation of fluorescence in situ hybridization (FISH) techniques for comparative physical mapping between Arabidopsis thaliana and Brassica rapa. A set of six bacterial artificial chromosomes (BACs) representing a 431-kb contiguous region of chromosome 2 of A. thaliana was mapped on both chromosomes and DNA fibers of B. rapa. This DNA fragment has a single location in the A. thaliana genome, but hybridized to four to six B. rapa chromosomes, indicating multiple duplications in the B. rapa genome. The sizes of the fiber-FISH signals from the same BACs were not longer in B. rapa than those in A. thaliana, suggesting that this genomic region is duplicated but not expanded in the B. rapa genome. The comparative fiber-FISH mapping results support that chromosomal duplications, rather than regional expansion due to accumulation of repetitive sequences in the intergenic regions, played the major role in the evolution of the B. rapa genome.

Associations among disease conditions, bone mineral density, and prevalent vertebral deformities in men and women 50 years of age and older: cross-sectional results from the Canadian Multicentre Osteoporosis Study.

This cross-sectional cohort study of 5566 women and 2187 men 50 years of age and older in the population-based Canadian Multicentre Osteoporosis Study was conducted to determine whether reported past diseases are associated with bone mineral density or prevalent vertebral deformities. We examined 12 self-reported disease conditions including diabetes mellitus (types 1 or 2), nephrolithiasis, hypertension, heart attack, rheumatoid arthritis, thyroid disease, breast cancer, inflammatory bowel disease, neuromuscular disease, Paget's disease, and chronic obstructive pulmonary disease. Multivariate linear and logistic regression analyses were performed to determine whether there were associations among these disease conditions and bone mineral density of the lumbar spine, femoral neck, and trochanter, as well as prevalent vertebral deformities. Bone mineral density measurements were higher in women and men with type 2 diabetes compared with those without after appropriate adjustments. The differences were most notable at the lumbar spine (+0.053 g/cm2), femoral neck (+0.028 g/cm2), and trochanter (+0.025 g/cm2) in women, and at the femoral neck (+0.025 g/cm2) in men. Hypertension was also associated with higher bone mineral density measurements for both women and men. The differences were most pronounced at the lumbar spine (+0.022 g/cm2) and femoral neck (+0.007 g/cm2) in women and at the lumbar spine (+0.028 g/cm2) in men. Although results were statistically inconclusive, men reporting versus not reporting past nephrolithiasis appeared to have clinically relevant lower bone mineral density values. Bone mineral density differences were -0.022, -0.015, and -0.016 g/cm2 at the lumbar spine, femoral neck, and trochanter, respectively. Disease conditions were not strongly associated with vertebral deformities. In summary, these cross-sectional population-based data show that type 2 diabetes and hypertension are associated with higher bone mineral density in women and men, and nephrolithiasis may be associated with lower bone mineral density in men. The importance of these associations for osteoporosis case finding and management require further and prospective studies.

Aerobic heat shock activates trehalose synthesis in embryos of Artemia franciscana.

Encysted embryos (cysts) of the brine shrimp, Artemia franciscana, contain large amounts of trehalose which they use as a major substrate for energy metabolism and biosynthesis for development under aerobic conditions at 25 degrees C. When cysts are placed at 42 degrees C (heat shock) these pathways stop, and the cysts re-synthesize the trehalose that was utilized during the previous incubation at 25 degrees C. Glycogen and glycerol, produced from trehalose at 25 degrees C, appear to be substrates for trehalose synthesis during heat shock. Anoxia prevents trehalose synthesis in cysts undergoing heat shock. These results are consistent with the view that trehalose may play a protective role in cells exposed to heat shock, and other environmental insults, in addition to being a storage form of energy and organic carbon for development.

Glycolysis compared in intact, permeabilized and sonicated L-929 cells.

The effects of incubation time and cell density on glycolytic rate were examined in suspensions of intact, permeabilized and sonicated L-929 cells. Sonicates exhibited strong dependence on cell density and a distinct lag in glycolytic rate, while intact cells showed no cell density dependence and linear glycolytic rates. Permeabilized cells exhibited linear glycolytic rates, but sometimes showed dependence on cell density. Rates of lactate production (nmol at 30 min/10(6) cells) were highest in sonicates and lowest in intact cells. These results are interpreted as support for the previously proposed hypothesis that enzymes of the glycolytic pathway are highly organized in intact L-929 cells.

Area characteristics and individual-level socioeconomic position indicators in three population-based epidemiologic studies.

PURPOSE: There is growing interest in incorporating area indicators into epidemiologic analyses. Using data from the 1990 U.S. Census linked to individual-level data from three epidemiologic studies, we investigated how different area indicators are interrelated, how measures for different sized areas compare, and the relation between area and individual-level social position indicators. METHODS: The interrelations between 13 area indicators of wealth/income, education, occupation, and other socioenvironmental characteristics were investigated using correlation coefficients and factor analyses. The extent to which block-group measures provide information distinct from census tract measures was investigated using intraclass correlation coefficients. Loglinear models were used to investigate associations between area and individual-level indicators. RESULTS: Correlations between area measures were generally in the 0.5--0.8 range. In factor analyses, six indicators of income/wealth, education, and occupation loaded on one factor in most geographic sites. Correlations between block-group and census tract measures were high (correlation coefficients 0.85--0.96). Most of the variability in block-group indicators was between census tracts (intraclass correlation coefficients 0.72--0.92). Although individual-level and area indicators were associated, there was evidence of important heterogeneity in area of residence within individual-level income or education categories. The strength of the association between individual and area measures was similar in the three studies and in whites and blacks, but blacks were much more likely to live in more disadvantaged areas than whites. CONCLUSIONS: Area measures of wealth/income, education, and occupation are moderately to highly correlated. Differences between using census tract or block-group measures in contextual investigations are likely to be relatively small. Area and individual-level indicators are far from perfectly correlated and provide complementary information on living circumstances. Differences in the residential environments of blacks and whites may need to be taken into account in interpreting race differences in epidemiologic studies.

Dog-bite induced sepsis: a report of four cases.

Occasionally, a dog-bite is complicated by a systemic overwhelming infection. We report four consecutive patients who were admitted to our intensive care unit because of sepsis syndrome following dog-bites. The history of these patients did not reveal any immunocompromising conditions. Capnocytophaga canimorsus (C. canimorsus) was cultured from the blood culture of 2 patients. Our data illustrate that in patients with lack of immune-deficiency severe sepsis may develop.

Platelet GPIIb/IIIa receptor occupancy studies using a novel fluoresceinated cyclic Arg-Gly-Asp peptide.

DMP 728 is a potent and specific platelet GPIIb/IIIa antagonist. Like all GPIIb/IIIa antagonists, DMP 728 has a steep dose-response relationship in inhibiting platelet aggregation. In this study the relationships between receptor occupancy, platelet aggregation and bleeding time was determined in anesthetized dogs after intravenous infusion of DMP 728 (0.01 and 0.1 mg/kg/2h). Receptor occupancy was determined by flow cytometry using XL086, a novel fluorescent cyclic RGD peptide that binds to GPIIb/IIIa with high specificity and affinity (kd approximately 55 nM). Mean number of GPIIb/IIIa as determined by flow cytometric assay was approximately 53,8000 and 79,000 on unactivated and ADP-activated platelets respectively. After DMP 728 intravenous infusion, there was a dose- and time-dependent increase in receptor occupancy, inhibition of platelet aggregation and bleeding time. The two methods of receptor occupancy determination correlate with each other with an r2 = 0.78. The present data suggest that blockade of only 40-60% (approximately 40,000 receptors) of the total platelet GPIIb/IIIa was required to achieve > 90% inhibition of platelet aggregation and > 15 min bleeding time. Our results showed the potential clinical utility of this approach in the study of GPIIb/IIIa dose-response relationship.

The role of cadherin endocytosis in endothelial barrier regulation: involvement of protein kinase C and actin-cadherin interactions.

We have previously reported that exposure of endothelial monolayers to low (0.12 mM) extracellular calcium significantly decreased the endothelial solute barrier, and that this effect was reversed by restoring 'normal' (1.2 mM) calcium (1). This effect was shown to be dependent on cadherins, however the molecular mechanisms through which barrier was altered by low calcium were not characterized. Here we investigated the mechanism of increased endothelial permeability produced by low calcium exposure. Endothelial permeability was significantly increased by exposure to low (0.12 mM) calcium; this effect was attenuated by pre-treatment with the protein kinase C (PKC) inhibitor, staurosporine (2 x 10(-7) M) for 30 min. Cell border retraction and gap formation produced by low calcium was also prevented by staurosporine. Treatment of monolayers with 0.12 mM calcium also stimulated the endocytosis of endothelial cadherins. This low calcium mediated cadherin endocytosis was also prevented by pretreatment with staurosporine. Low calcium mediated endocytosis was also prevented by the actin filament toxin, cytochalasin D (1 ug/ml, 30 min). We conclude that the mechanism of low calcium mediated loss of endothelial barrier function is mediated in part by a PKC dependent endocytosis of endothelial cadherins, which may involve interactions with the actin cytoskeleton. Physiological regulation of the in vivo endothelial barrier may also involve PKC dependent-actin mediated endocytosis of cadherin junctional elements.

Radiation exposure during fluoroscopically assisted pedicle screw insertion in the lumbar spine.

STUDY DESIGN: An experimental model to assess radiation exposure during lumbar pedicle screw insertion. OBJECTIVES: To measure skin (patient) and scatter (surgeon) doses of radiation during lumbar spine fluoroscopy to assess safety of the procedure for both the surgeon and patient and determine best practice. SUMMARY OF BACKGROUND DATA: Fluoroscopy assists with accuracy of pedicle screw placement, yet the optimal technique of C-arm use and risk to both patient and operating room staff from radiation exposure are unknown. METHODS: Entry- and scatter-dose recordings were made using a digital dosimeter while screening an anthropomorphic phantom prone on a radiolucent operating table. The source was positioned both superiorly and inferiorly with the height varied in the latter orientation to create a working space under the C-arm. The senior author's fluoroscopy records were reviewed in 140 consecutive cases. RESULTS: In a series of 140 patients who underwent pedicle screw fixation, the fluoroscopy time was 1.4 minutes per case or 0.33 minutes per screw. In the source-superior position, the effective dose received by the patient was approximately 2.3 mSv per case. In the source-inferior position with a working space of 300 mm, the effective dose was 6.8 mSv. Scatter dose to the surgeon was higher in the source-superior position but was still less than 10% of recommended limits for the hand, thyroid, and eyes. CONCLUSIONS: The source-superior position is the preferred position for pedicle screw screening if a working space is required. Patient exposure is minimized, and surgeon dose is well within current recommendations.

Assessment of the variation in cerebrovascular reactivity in head injured patients.

Several indices have been reported which correlate with autoregulatory function [2, 3]. However, before critical thresholds for targeting therapy can be defined, a better understanding of the inherent variability of cerebrovascular reactivity as measured by these indices is required. In this study, patients had BP, ICP and bilateral MCA TCD velocity monitored before, during and after BP and CO2 challenges, applied in a random order, with measurements taken within 48 hours of injury. Four indices of reactivity were calculated: the PRx, the CORRx and the FVreact & ICPreact. At 48 hours post-injury inter-patient variation in cerebrovascular reactivity, as measured by these indices, is large and injury specific factors remain important determinants of the variance. Within patient analysis has identified instances where the combined monitoring of the PRx and the CORRx may provide information about the function of pressure autoregulation and further study of the combined use of these two indices of reactivity is warranted.

The effect of exogenous progestins on endogenous progesterone secretion in pregnant mares.

Twenty-four pregnant, light horse mares were used in a study to determine if an exogenous progestin or progesterone would alter serum concentrations of progesterone. On day 40 of gestation, mares were randomly assigned to one of three administration groups: 1) 250 mg of progesterone in oil every other day, 2) 22 mg of Altrenogest (Regumate, American Hoechst, Somerville, NJ 08876) orally every day, or 3) 10 ml of neobee oil (control) orally every day. The treatment period was from day 40 to 105. Pregnancy status was monitored on days 40, 60, 80, 100 and 105 and a single jugular blood sample was obtained daily from days 40 to 46, 69 to 75 and 99 to 105. Serum concentrations of progesterone were determined by radioimmunoassay. Concentrations of progesterone were similar (P>0.05) among groups at each sampling period. Overall concentrations of progesterone increased (P<0.001) from days 40 to 46. Injection of 250 mg of progesterone in oil failed (P>0.05) to maintain concentrations of progesterone in serum above baseline for 24 hr. Thus higher doses and/or more frequent injections would be needed in order to increase concentrations of progesterone above those seen in untreated controls. In summary, Altrenogest was found to be a nonstressful, convenient method of administering progestins to pregnant mares without altering their endogenous secretion of progesterone.