HESI workshop summary: Interpretation of developmental and reproductive toxicity endpoints and the impact on data interpretation of adverse events

The Health and Environmental Sciences Institute Developmental and Reproductive Toxicology (HESI-DART) group held a hybrid in-person and virtual workshop in Washington, DC, in 2022. The workshop was entitled, "Interpretation of DART in Regulatory Contexts and Frameworks." There were 154 participants (37 in person and 117 virtual) across 9 countries. The purpose of the workshop was to capture key consensus approaches used to assess DART risks associated with chemical product exposure when a nonclinical finding is identified. The decision-making process for determining whether a DART endpoint is considered adverse is critical because the outcome may have downstream implications (e.g., increased animal usage, modifications to reproductive classification and pregnancy labeling, impact on enrollment in clinical trials and value chains). The workshop included a series of webinar modules to train and engage in discussions with federal and international regulators, clinicians, academic investigators, nongovernmental organizations, contract research organization scientists, and private sector scientists on the best practices and principles of interpreting DART and new approach methodologies in the context of regulatory requirements and processes. Despite the differences in regulatory frameworks between the chemical and pharmaceutical sectors, the same foundational principles for data interpretation should be applied. The discussions led to the categorization of principles, which offer guidance for the systematic interpretation of data. Step 1 entails identifying any hazard by closely analyzing the data at the study endpoint level, while Step 2 involves assessing risk using weight of evidence. These guiding principles were derived from the collective outcomes of the workshop deliberations.

Scientific AI in Materials Science: a Path to a Sustainable and Scalable Paradigm

Recently there has been an ever-increasing trend in the use of machine learning (ML) and artificial intelligence (AI) methods by the materials science, condensed matter physics, and chemistry communities. This perspective article identifies key scientific, technical, and social opportunities that the materials community must prioritize to consistently develop and leverage Scientific AI (SciAI) to provide a credible path towards the advancement of current materials-limited technologies. Here we highlight the intersections of these opportunities with a series of proposed paths forward. The opportunities are roughly sorted from scientific/technical (e.g. development of robust, physically meaningful multiscale material representations) to social (e.g. promoting an AI-ready workforce). The proposed paths forward range from developing new infrastructure and capabilities to deploying them in industry and academia. We provide a brief introduction to AI in materials science and engineering, followed by detailed discussions of each of the opportunities and paths forward.

An Inter-Laboratory Study of Zn-Sn-Ti-O Thin Films using High-Throughput Experimental Methods

High-throughput experimental (HTE) techniques are an increasingly important way to accelerate the rate of materials research and development for many technological applications. However, there are very few publications on the reproducibility of the HTE results obtained across different laboratories for the same materials system, and on the associated sample and data exchange standards. Here, we report a comparative study of Zn-Sn-Ti-O thin films materials using high-throughput experimental methods at National Institute of Standards and Technology (NIST) and National Renewable Energy Laboratory (NREL). The thin film sample libraries were synthesized by combinatorial physical vapor deposition (cosputtering and pulsed laser deposition) and characterized by spatially resolved techniques for composition, structure, thickness, optical, and electrical properties. The results of this study indicate that all these measurement techniques performed at two different laboratories show excellent qualitative agreement. The quantitative similarities and differences vary by measurement type, with 95% confidence interval of 0.1-0.2 eV for the band gap, 24-29 nm for film thickness, and 0.08 to 0.37 orders of magnitude for sheet resistance. Overall, this work serves as a case study for the feasibility of a High-Throughput Experimental Materials Collaboratory (HTE-MC) by demonstrating the exchange of high-throughput sample libraries, workflows, and data.

An apparatus for spatially resolved, temperature dependent reflectance measurements for identifying thermochromism in combinatorial thin film libraries

A metrology and data analysis protocol is described for high throughput determination of thermochromic metal-insulator phase diagrams for lightly substituted VO2 thin films. The technique exploits the abrupt change in near infrared optical properties, measured in reflection, as an indicator of the temperature- or impurity-driven metal-insulator transition. Transition metal impurities were introduced in a complementary combinatorial synthesis process for producing thin film libraries with the general composition space V(1-x-y)M(x)M'(y)O2, with M and M' being transition metals and x and y varying continuously across the library. The measurement apparatus acquires reflectance spectra in the visible or near infrared at arbitrarily many library locations, each with a unique film composition, at temperatures of 1 °C-85 °C. Data collection is rapid and automated; the measurement protocol is computer controlled to automate the collection of thousands of reflectance spectra, representing hundreds of film compositions at tens of different temperatures. A straightforward analysis algorithm is implemented to extract key information from the thousands of spectra such as near infrared thermochromic transition temperatures and regions of no thermochromic transition; similarly, reflectance to the visible spectrum generates key information for materials selection of smart window materials. The thermochromic transition for 160 unique compositions on a thin film library with the general formula V(1-x-y)M(x)M'(y)O2 can be measured and described in a single 20 h experiment. The resulting impurity composition-temperature phase diagrams will contribute to the understanding of metal-insulator transitions in doped VO2 systems and to the development of thermochromic smart windows.

Interrogating the Carbon and Oxygen K-Edge NEXAFS of a CO2-Dosed Hyperbranched Aminosilica

Using near-edge X-ray absorption fine structure (NEXAFS) spectroscopy, we shed light on the nature of the interaction between CO2 and the amine moieties in a hyperbranched aminosilica (HAS) material, a porous aminosilica composite with great potential for postcombustion carbon capture applications. We show that after dosing a pristine (annealed) HAS sample with CO2, the C K-edge NEXAFS spectrum presents a new π* resonance at 289.9 eV, which can be attributed to the formation of a C═O (carbonyl) bond. Additional analyses of the O K-edge using model samples containing carbamate, carbonate, and bicarbonate functional groups as reference demonstrate a carbamate bonding mechanism for the chemical adsorption of CO2 by the HAS material under the conditions employed. These findings show the capability of the C and O K-edge NEXAFS technique to identify CO2-adsorbate species despite the high concentration of C and O atoms inherently present in the sample (prior to CO2 dosing) and the significant similarities between the possible adsorbates.

Release of targeted p53 from the mitochondrion as an early signal during mitochondrial dysfunction

Increased accumulation of p53 tumor suppressor protein is an early response to low-level stressors. To investigate the fate of mitochondrial-sequestered p53, mouse embryonic fibroblast cells (MEFs) on a p53-deficient genetic background were transfected with p53-EGFP fusion protein led by a sense (m53-EGFP) or antisense (c53-EGFP) mitochondrial import signal. Rotenone exposure (100nM, 1h) triggered the translocation of m53-EGFP from the mitochondrion to the nucleus, thus shifting the transfected cells from a mitochondrial p53 to a nuclear p53 state. Antibodies for p53 serine phosphorylation or lysine acetylation indicated a different post-translational status of recombinant p53 in the nucleus and mitochondrion, respectively. These data suggest that cycling of p53 through the mitochondria may establish a direct pathway for p53 signaling from the mitochondria to the nucleus during mitochondrial dysfunction. PK11195, a pharmacological ligand of mitochondrial TSPO (formerly known as the peripheral-type benzodiazepine receptor), partially suppressed the release of mitochondria-sequestered p53. These findings support the notion that p53 function mediates a direct signaling pathway from the mitochondria to nucleus during mitochondrial dysfunction.

Measurement, standards, and data needs for CO2 capture materials: a critical review

The commercial deployment of cost-effective carbon capture technology is hindered partially by the lack of a proper suite of materials-related measurements, standards, and data, which would provide critical information for the systematic design, evaluation, and performance of CO2 separation materials. Based on a literature search and conversations with the carbon capture community, we review the current status of measurements, standards, and data for the three major carbon capture materials in use today: solvents, solid sorbents, and membranes. We highlight current measurement, standards and data activities aimed to advance the development and use of carbon capture materials and major research needs that are critical to meet if innovation in carbon capture materials is to be achieved. The review reveals that although adsorbents are considered to have great potential to reduce carbon capture cost, there is no consensus on the experimental parameters to be used for evaluating sorbent properties. Another important finding is the lack of in situ experimental tools for the structural characterization of solid porous materials during CO2 adsorption, and computational methods that would enable a materials-by-design approach for their development.

Genome annotation errors in pathway databases due to semantic ambiguity in partial EC numbers

We report on a new type of systematic annotation error in genome and pathway databases that results from the misinterpretation of partial Enzyme Commission (EC) numbers such as ‘1.1.1.-’. This error results in the assignment of genes annotated with a partial EC number to many or all biochemical reactions that are annotated with the same partial EC number. That inference is faulty because of the ambiguous nature of partial EC numbers. We have observed this type of error in multiple databases, including KEGG, VIMSS and IMG, all of which assign genes to KEGG pathways. The Escherichia coli subset of the KEGG database exhibits this error for 6.8% of its gene-reaction assignments. For example, KEGG contains 17 reactions that are annotated with EC 1.1.1.-. A group of three E.coli genes, b1580 [putative dehydrogenase, NAD(P)-binding, starvation-sensing protein], b3787 (UDP-N-acetyl-d-mannosaminuronic acid dehydrogenase) and b0207 (2,5-diketo-d-gluconate reductase B), is assigned to 15 of those reactions, despite experimental evidence indicating different single functions for two of the three genes. Furthermore, the databases (DBs) are internally inconsistent in that the description of gene functions for genes with partial EC numbers is inconsistent with the activities implied by reactions to which the genes were assigned. We infer that these inconsistencies result from the processing used to match gene products to reactions within KEGG's metabolic pathways. These errors affect scientists who use these DBs as online encyclopedias and they affect bioinformaticists who use these DBs to train and validate newly developed algorithms.

Identifying, appraising, and implementing medical education curricula: a guide for medical educators

As physicians' requirements for knowledge and skills evolve, medical educators often encounter the need for new curricula. This article presents an approach to identifying, appraising, and adapt-ing an established curriculum as an alternative to developing a new one. A published managed care curriculum is reviewed as an educational case example.

Effects of a chewable sodium bicarbonate oral composition on plaque and gingivitis

The purpose of this pilot study was to evaluate the effects of an effervescent sodium bicarbonate based oral composition on plaque and gingivitis. Subjects selected for this study presented at screening with moderate plaque and American Academy of Periodontology (AAP) Type I/II periodontal status. At baseline, subjects were allocated to one of two groups by simple randomization; placebo (n=16) and active (n=16). During the study two subjects withdrew due to non-compliance and one because of a death in the family. Data were collected at baseline, day 14, and day 28. The Plaque Index (PI) of Silness and Loe was used to quantify the amount of supragingival plaque surrounding six selected teeth (3,14,8,19,24,30), and the Gingival Index (GI) of Loe and Silness was used to assess bleeding tendencies and visual appearance on the same six teeth. A soft tissue oral assessment was completed at each visit. Subjects were asked to perform study treatment three times a day, after meals, and continue with normal oral hygiene procedures. Subjects were requested to complete a 28-day diary to assess compliance. Data were analyzed using repeated measures analysis of variance. There were no statistically significant differences between the placebo and the active product groups and no statistical significant interaction between product and location within the mouth or visit for either the plaque or gingival scores. Results reveal the product was safe to oral tissues and was well accepted by subjects.

Results from the Lake Michigan Mass Balance study: concentrations and fluxes of atmospheric polychlorinated biphenyls and trans-nonachlor

In this paper, we summarize the data and methods used to estimate atmospheric exchange of polychlorinated biphenyls (PCBs) and trans-nonachlor with Lake Michigan. This work was conducted as part of the Lake Michigan Mass Balance (LMMB) study. For the atmospheric component of the LMMB, more than 400 gas- and particulate-phase samples were collected at eight sites on the shore around the lake (shoreline) and at 14 sites on the lake (over-water). We review the quality of the data set; describe the concentrations in atmospheric gas and particulate phases; report local, instantaneous, net gas fluxes; and estimate annual deposition of the particle-associated compounds. The quality of the data set is high except for a subset of over-water samples where PCB contamination is suspected. Gas-phase trans-nonachlor concentrations (although not the resulting gas fluxes) are inversely correlated with latitude and positively correlated with temperature. Gas-phase sigmaPCBs (sum of 98 congener groups) are highest in concentration at the Chicago site and lowest at the Sleeping Bear Dunes site. The resulting sigmaPCB gas fluxes exhibit a seasonality that reflects elevated summertime gas-phase concentrations not compensated by temperature-corrected Henry's law coefficients. Particulate-phase deposition is much smaller in magnitude than gas fluxes, for either compound. Gas and particulate fluxes are comparable only at the Chicago site and only when large (> 10 microm) particulates are considered.

Discrete atom imaging of one-dimensional crystals formed within single-walled carbon nanotubes

The complete crystallography of a one-dimensional crystal of potassium iodide encapsulated within a 1.6-nanometer-diameter single-walled carbon nanotube has been determined with high-resolution transmission electron microscopy. Individual atoms of potassium and iodine within the crystal were identified from a phase image that was reconstructed with a modified focal series restoration approach. The lattice spacings within the crystal are substantially different from those in bulk potassium iodide. This is attributed to the reduced coordination of the surface atoms of the crystal and the close proximity of the van der Waals surface of the confining nanotube.

Residents' medical information needs in clinic: are they being met?

PURPOSE

Little is known about how often residents encounter unanswered clinical questions in their training. This knowledge would facilitate the development of curricula to help residents practice evidence-based medicine. This study was conducted to determine the frequency, characteristics, and pursuit of residents' clinical questions.

SUBJECTS AND METHODS

Residents in a university-based primary care internal medicine program were observed in two hospital-based teaching clinics. Residents were interviewed after each patient encounter to determine whether they had any remaining clinical questions. At the end of each clinic session, they recorded their level of agreement with a series of statements about factors that were expected to motivate residents to seek the answers to each question. One week later, residents were contacted to determine if they had pursued these questions.

RESULTS

Sixty-four residents were interviewed after 401 (99%) of 404 patient encounters. They identified 280 new questions, approximately 2 questions for every 3 patients. The most common types of questions were related to therapy (38%) or diagnosis (27%). The residents were subsequently contacted about 277 (99%) of their questions. Of these, only 80 (29%) were pursued, most commonly by consulting textbooks (31%), original articles (21%), or attending physicians (17%). In a multivariable analysis, belief that the patient expected the answer (odds ratio [OR] = 2.3, 95% confidence interval [CI]: 1.3 to 4.0, P = 0.004) and fear of malpractice exposure (OR = 2.1, 95% CI: 1.0 to 4.3, P = 0.05) were associated with information pursuit. Lack of time (60%) and forgetting the question (29%) were the most frequent reasons for failing to pursue a question.

CONCLUSION

Residents frequently encountered new clinical questions in the outpatient clinic, but infrequently answered them. Efforts to demonstrate the feasibility of timely searches, remind them of their questions, and reinforce the exigency (educational if not clinical) of all questions may reclaim missed opportunities for self-directed learning.

Uranium(VI) sulfilimine complexes: a new class of nitrogen analogues of the uranyl ion

The compound tetraphenylphosphonium tetrachlorooxo-S,S-diphenylsulfiliminatouranium, [Ph4P][UOCl4(NSPh2)], has been prepared in high yield from [Ph4P][UOCl5] and [Ph2S=NSiMe3]. An X-ray structure of this compound shows that the uranium atom has a pseudooctahedral geometry with oxygen and nitrogen atoms in trans positions. The structure of the analogous phosphoriminato complex [Ph4P][UOCl4(NPPh3)] has been determined for comparison. Derivatization of the sulfide group shows that only a limited range of functionalization confers stability toward reduction. The emission spectrum of the first electronic excited state reveals a greatly reduced energy compared with that of the uranyl ion. This red shift in the transition is consistent with the weakening of the U-N bond relative to the U-O bond.

Evidence-based medicine training in graduate medical education: past, present and future

Evidence-based medicine (EBM) training remains a challenge to educators, particularly in graduate medical education. In this article, I trace the history of EBM in American medical education, review traditional journal clubs and contrast them to free-standing EBM curricula, petition for the advancement of integrated EBM teaching and propose an agenda for future work. Traditional journal clubs are unsuitable to teach evidence-based decision making because of their exclusive focus on critical appraisal. In contrast, EBM curricula cover the identification, appraisal and application of evidence in the context of individual patient scenarios. The effectiveness of some recent efforts reflects increasing attention to curriculum development principles and scientific rigour. The integration of EBM training into residents' established clinical venues offers theoretical educational advantages and confronts the challenge of practising EBM under the imperatives of 'real time' patient care. Initial responses to this formidable challenge show promise, but their feasibility and effectiveness remain to be explored. A more complete understanding of the epidemiology of residents' emerging clinical questions will inform continued curriculum development in integrated EBM training.

Pregnancy-dependent expression of leukaemia inhibitory factor (LIF), LIF receptor-beta and interleukin-6 (IL-6) messenger ribonucleic acids in the porcine female reproductive tract

Leukaemia inhibitory factor (LIF) and interleukin-6 (IL-6) are candidate embryo-maternal signalling molecules which are present within the uterine luminal micro-environment. We examined the relative expression of the mRNAs encoding LIF and IL-6, as well as the LIF-binding subunit (LIFR-beta) of the LIF receptor and, as a potential downstream cytokine-responsive gene, beta(2)-microglobulin (beta(2)m), in porcine peri-implantation conceptuses, and in placenta and endometrium during early and mid-pregnancy. Peri-implantation spherical and filamentous conceptuses expressed LIFR-beta and beta(2)m mRNAs with no LIF mRNA present. Rapid development in days 11/12 spherical conceptuses to the filamentous stage was accompanied by transiently increased IL-6 gene expression. The corresponding endometrium, in contrast, expressed LIF in addition to these other mRNAs. LIFR-beta, IL-6 and beta(2)m, but not LIF mRNAs, were expressed in the Jag-1 cell line, an in vitro model for porcine day 14 trophoblast. The greatest steady-state amounts of LIF, LIFR-beta and IL-6 mRNAs in both the endometrium and placenta were evident at the post-implantation stages (days 30 and 60>day 18 of pregnancy). Treatment of porcine endometrial explants with human recombinant (hr)LIF or hrIL-6 resulted in no change in, or diminished, the presence of endometrial beta(2)m mRNA, respectively. Addition of LIF to peri-implantation conceptus explant cultures, in contrast, induced beta(2)m mRNA synthesis. These results highlight the potential importance of both the endometrium and placenta as sources, as well as targets, of these cytokines throughout pregnancy. Cytokine modulation of beta(2)m, a known in vitro mitogen, may constitute one mechanism for local control of trophoblast and endometrial proliferation.

Evidence-based medicine training in internal medicine residency programs a national survey

To characterize evidence-based medicine (EBM) curricula in internal medicine residency programs, a written survey was mailed to 417 program directors of U.S. internal medicine residency programs. For programs offering a freestanding (dedicated curricular time) EBM curriculum, the survey inquired about its objectives, format, curricular time, attendance, faculty development, resources, and evaluation. All directors responded to questions regarding integrating EBM teaching into established educational venues. Of 417 program directors, 269 (65%) responded. Of these 269 programs, 99 (37%) offered a freestanding EBM curriculum. Among these, the most common objectives were performing critical appraisal (78%), searching for evidence (53%), posing a focused question (44%), and applying the evidence in decision making (35%). Although 97% of the programs provided MEDLINE, only 33% provided Best Evidence or the Cochrane Library. Evaluation was performed in 37% of the freestanding curricula. Considering all respondents, most programs reported efforts to integrate EBM teaching into established venues, including attending rounds (84%), resident report (82%), continuity clinic (76%), bedside rounds (68%), and emergency department (35%). However, only 51% to 64% of the programs provided on-site electronic information and 31% to 45% provided site-specific faculty development. One third of the training programs reported offering freestanding EBM curricula, which commonly targeted important EBM skills, utilized the residents' experiences, and employed an interactive format. Less than one half of the curricula, however, included curriculum evaluation, and many failed to provide important medical information sources. Most programs reported efforts to integrate EBM teaching, but many of these attempts lacked important structural elements.

Serum concentrations of melatonin during scotophase and photophase in 3, 4, 5 and 6 months old gilts and barrows

One-hundred-twenty prepubertal crossbred gilts (Hampshire x Duroc) x (Yorkshire x Landrace) were removed from the nursery at 68.7+/-0.4 days of age and 23.6+/-0.9 kg body weight and relocated to a conventional grower-finisher unit. In addition, 60 barrows of similar genetics were relocated from the nursery at 71.0+/-0.5 days of age and 27.4+/-0.5 kg body weight to the same building. Twelve mature anestrous ewes that weighed 77.0+/-2.4 kg were assigned randomly to one of four pens of equal dimensions among the pens containing pigs. Ewes were included in this study to serve as positive controls since their secretory profiles of melatonin are well characterized. All pigs were bled by jugular venipuncture at approximately 3, 4, 5 and 6 months of age. At each age in the pigs and the mature ewes, a single sample was obtained during photophase and scotophase. Illumination intensity during the period of incandescent lighting averaged 220 1x. Blood collection was initiated approximately 4 h after sunrise and 3.5-4 h after sunset. The proportion of animals that exhibited a nocturnal rise in melatonin (MEL) was similar (P > 0.05) between gilts and barrows, but was higher (P < 0.002) in ewes than in pigs at each age examined. A greater proportion (P = 0.007) of 3 month old barrows had a nocturnal rise of MEL than any other age of barrow. Similarly, there was a tendency (P = 0.06) for more 3 month old gilts to exhibit a nocturnal increase in serum MEL than 4, 5 or 6 month old gilts.

Graduate medical education training in clinical epidemiology, critical appraisal, and evidence-based medicine: a critical review of curricula

PURPOSE

To systematically review the published literature on graduate medical education (GME) curricula in clinical epidemiology, critical appraisal, and evidence-based medicine (EBM).

METHOD

The author searched the Medline and Educational Resources Information Center (ERIC) databases from 1973 through 1998, and also searched the references of the captured papers. The author reviewed all peer-reviewed reports of GME curricula (with or without effectiveness studies) in critical appraisal, clinical epidemiology, or evidence-based medicine, extracting objectives, formats, and evaluations (including effectiveness, process, and satisfaction). For effectiveness evaluations, he also identified the outcomes, outcome measures, methodologic characteristics, and results.

RESULTS

The search produced 18 reports. The most common objective of the curricula described in the reports was improving critical skills; the most common format was resident-directed small-group seminar. The most common outcome-evaluation measure was a multiple-choice examination. Only seven of the reports evaluated the curricula's effectiveness, and only four met a minimum methodologic standard of a pretest-posttest controlled trial. The impacts on critical appraisal skills of the curricula in those four reports ranged from no effect to a 23% net absolute increase in test scores.

CONCLUSION

These reports provide useful guides for medical educators, but many suffered from incomplete descriptions and inadequate evaluations of their curricula. The curricula themselves often focused on critical appraisal to the exclusion of other EBM skills and had limited effectiveness. In addition to increased methodologic rigor, future studies should focus on more meaningful outcome evaluations. Curricula should use residents' actual clinical experiences and teach EBM skills in real time in existing clinical and educational venues.

Paracrine inducers of uterine endometrial spermidine/spermine N1-acetyltransferase gene expression during early pregnancy in the pig

The endogenous factors that underlie the transient induction of the gene encoding spermidine/spermine N1-acetyltransferase (SSAT), the rate-limiting enzyme in cellular polyamine catabolism, in pig uterine endometrium during periimplantation are not known. The present study examined a number of peptide growth factors and regulatory molecules that are present within the uterine environment at early pregnancy, coincident with maximal SSAT gene expression, for their ability to manifest endogenous SSAT gene-inducing activity. Basal SSAT expression in luminal epithelial cells was higher (p < 0. 01) than that for glandular epithelial (GE) or stromal (ST) cells. Recombinant human insulin-like growth factor-I (IGF-I; 50 ng/ml) had no effect on steady-state SSAT mRNA levels, but it increased mitogenesis in all three cell types. In contrast, IGF-I caused a marked induction (p < 0.01) of SSAT mRNA levels in the human endometrial carcinoma cell line Hec-1-A. Uterine explants incubated with interleukin-6, transforming growth factor alpha, epidermal growth factor (each at 1, 10, and 100 ng/ml), retinoic acid and retinol (each at 0.01, 0.1, and 1 microM), and estradiol-17beta (10 nM) had SSAT mRNA levels similar to controls. By contrast, leukemia inhibitory factor (LIF; at 10 and 100 ng/ml) caused a modest, but significant (p < 0.05), increase in SSAT mRNA levels over those of untreated explants. This effect of LIF, however, did not approach the level of induction observed in GE or ST cells after addition of medium conditioned by Day 12 or 17 porcine conceptuses and in endometrial explants supplemented with medium conditioned by Day 21 porcine conceptuses or a continuous cell line (Jag-1) derived from Day 14 porcine trophoblast. We suggest that transient induction of endometrial SSAT gene expression at implantation is mediated by the functional interactions of specific conceptus-derived regulatory factors, distinct from estrogen, with endometrial-derived factor(s) such as LIF. These complex interactions are probably requisite for the transient, yet dramatic, induction of SSAT gene expression and may be critical for successful implantation.

Parent assessment of psychological and behavioral functioning following pediatric acquired brain injury

OBJECTIVE

Compare the measured prevalence rate of psychopathology and behavior disorders in 29 children with acquired brain injuries using four parent-report instruments.

METHOD

Two questionnaires, the Child Behavior Checklist (CBCL) and the Personality Inventory for Children (PIC-R) and two interview measures, the Diagnostic Interview for Children and Adolescents (DICA-R) and the Vineland Adaptive Behavior Scales (VABS), were completed following injury or diagnosis.

RESULTS

The DICA-R identified the highest prevalence of anxiety disorders and acting-out behaviors, whereas the CBCL identified the lowest prevalence. Opposite results were found within the domain of attentional problems. Interview measures were more concordant for global psychological impairment than were questionnaires.

DISCUSSION

Discordant findings across measures are discussed in terms of type of disorder, classification model, response format, item characteristics, and scaling.

Proteolysis of insulin-like growth factor-binding proteins (IGFBPs) within the pig uterine lumen associated with peri-implantation conceptus development

Pig conceptuses undergo morphological development from spherical to filamentous forms during days 10 to 12 of pregnancy, coincident with a high content of mRNAs encoding insulin-like growth factor (IGF)-I in the uterine endometrium and secretion of IGF-I into the uterine lumen. The potential regulation by developing conceptuses of the bioavailability of IGF-binding proteins (IGFBPs) within the uterine microenvironment was investigated. Uterine luminal flushings (ULFs) were obtained between days 10 and 18 of pregnancy and the presence of specific IGFBPs was detected by ligand blot analysis. ULFs collected at days 10 and 11 of pregnancy contained 46 and 43 kDa IGFBP-3, several IGFBPs of about 30 kDa including IGFBP-2, and an unidentified 26 kDa IGFBP; IGFBP-3 was the most abundant. By day 12, however, IGFBPs were substantially diminished or undetectable. Examination of the morphology of flushed conceptuses revealed that the loss of IGFBPs in ULF was associated with the transition from spherical to filamentous morphology. The abundance of IGFBP-3 mRNA in uterine endometrium, as monitored by blot-hybridization, was not altered in a similar way, suggesting that lack of IGFBP-3 in 'filamentous' ULF resulted from proteolysis rather than from decreased expression of the IGFBP-3 gene. Consistent with this, incubation of 'spherical' ULF with or without added 'filamentous' ULF at 37 degrees C resulted in the disappearance of endogenous IGFBP-3 only in 'spherical + filamentous' ULF. The protease activity in 'filamentous' ULF was inhibited by EDTA, but unlike matrix metalloproteinases, was not zinc ion-dependent or inhibited by 1,10-phenanthroline. Moreover, this activity was partially inhibited by the serine protease inhibitor aprotinin, but not by 4-(2-aminoethyl)-benzenesulfonyl fluoride (AEBSF), a known inhibitor of plasmin. The IGFBP protease activity of ULF may therefore comprise a group of enzymes including an unidentified serine protease. The results suggest that elongating pig conceptuses induce IGFBP protease activity which may increase the intrauterine bioavailability of IGF.

Control of secretory leukocyte protease inhibitor gene expression in the porcine periimplantation endometrium: a case of maternal-embryo communication

The contributions of the conceptus (embryo and associated membranes) and of the maternal endocrine milieu to control of endometrial secretory leukocyte protease inhibitor (SLPI, also designated antileukoproteinase) expression during the periimplantation stages of embryo development were examined in the present study. Uterine endometrium from distinct sites was collected from pigs at Days 16-25 of pregnancy and analyzed for steady-state SLPI mRNA levels. Endometrium situated directly beneath conceptuses (mesometrial) had greater (p < 0.05) SLPI mRNA levels than that obtained from antimesometrial and interimplantation sites and myometrium. This site-specific difference was most pronounced during late (Days 19-21) and post (Days 23-25)-implantation stages and was also observed, albeit to a lesser degree, for the mRNA encoding uteroferrin (Uf). Conditioned medium (CM; 50% v:v) from Day 21, but not Day 12, conceptuses increased (p < 0.05) SLPI mRNA levels, while neither CM affected mRNA levels for Uf and several other genes expressed in endometrial explants. One inducing factor in Day 21 CM was characterized as a low-molecular-mass (< 12 kDa), relatively heat-stable protein. Transforming growth factor (TGF alpha) increased (p < 0.05), epidermal growth factor (EGF) tended to increase (p = 0.10), and insulin-like growth factor (IGF)-I and IGF-II had no effect (p > 0.10) on, SLPI mRNA levels in Day 12 endometrial explants. Medium conditioned by the pig trophoblast cell line, Jag-1, but not by other mammalian cell lines, had SLPI inducer activity. The maternal endocrine contribution to SLPI gene expression was examined using freshly isolated and short-term-cultured Day 12 and Day 21 pregnant pig endometrium. Steady-state SLPI mRNA levels were increased (p < 0.05) in Day 12, but not Day 21, tissues upon short-term culture in serum-free medium. This increase was time dependent, was similarly demonstrated for Uf mRNA, was not observed in corresponding lung and liver, and was inhibited by inclusion of serum from pigs of diverse endocrine status. In summary, two potential modulators of endometrial SLPI gene expression were identified: 1) a conceptus-derived low-molecular-mass protein, possibly TGF alpha, that mediates in part the up-regulation of SLPI gene expression in endometrium closely associated with implantation sites, and 2) an inhibitory component(s) present in maternal serum. Results suggest opposing actions of maternal and embryonic factors at the maternal-embryo interface and highlight involvement of the periimplantation embryo in directing the spatiotemporal expression of endometrial genes implicated in its development.

The porcine insulin-like growth factor system: at the interface of nutrition, growth and reproduction

The IGF system is implicated in the regulation of cellular response to protein- and energy-restriction. Although it is clear that the IGF and their binding proteins are profoundly influenced by dietary factors, a number of important questions remain about this relationship. In particular, although studies to date have focused on nutritional modulation of hepatic IGF gene expression, the molecular mechanisms underlying metabolic regulation of liver IGF and IGF binding protein genes remain relatively unknown. Moreover, the potential effects of altered nutrition on the expression and/or actions of IGF system components in tissues other than the liver have been examined only in cursory fashion. Many of these studies have used rats, an admittedly important model, but one which differs from the human in a potentially significant way: rats lack circulating IGF-II and IGFBP-2 during post-weaning and adult life. Here, we summarize current research on the porcine IGF system and highlight the particular usefulness this system may offer for unraveling the complex relationships of nutrition and systemic/local IGF expression and actions that are relevant to human nutritional physiology.

Impact of an evidence-based medicine curriculum based on adult learning theory

OBJECTIVE

To develop and implement an evidence-based medicine (EBM) curriculum and determine its effectiveness in improving residents' EBM behaviors and skills.

DESIGN

Description of the curriculum and a multifaceted evaluation, including a pretest-posttest controlled trial.

SETTING

University-based primary care internal medicine residency program.

PARTICIPANTS

Second- and third-year internal medicine residents (N = 34).

INTERVENTIONS

A 7-week EBM curriculum in which residents work through the steps of evidence-based decisions for their own patients. Based on adult learning theory, the educational strategy included a resident-directed tutorial format, use of real clinical encounters, and specific EBM facilitating techniques for faculty.

MEASUREMENTS AND MAIN RESULTS

Behaviors and self-assessed competencies in EBM were measured with questionnaires. Evidence-based medicine skills were assessed with a 17-point test, which required free text responses to questions based on a clinical vignette and a test article. After the intervention, residents participating in the curriculum (case subjects) increased their use of original studies to answer clinical questions, their examination of methods and results sections of articles, and their self-assessed EBM competence in three of five domains of EBM, while the control subjects did not. The case subjects significantly improved their scores on the EBM skills test (8.5 to 11.0, p = .001), while the control subjects did not (8.5 to 7.1, p = .09). The difference in the posttest scores of the two groups was 3.9 points (p = .001, 95% confidence interval 1.9, 5.9).

CONCLUSIONS

An EBM curriculum based on adult learning theory improves residents' EBM skills and certain EBM behaviors. The description and multifaceted evaluation can guide medical educators involved in EBM training.

Lack of a nocturnal rise in serum concentrations of melatonin as gilts attain puberty

Twenty prepubertal crossbred gilts (Yorkshire x Hampshire x Duroc) weighing 98.1 +/- 4.2 kg at 5 mo of age were placed in an environmentally controlled room having a temperature of 18 degrees C and light:dark cycle of 12 h:12 h. Light intensity measured 700 lx at eye level to the gilts. Three mature ewes were penned adjacent to the gilts to serve as positive controls for the light-dark cycles. After a 30-d acclimation period, 10 gilts from the pool determined to be prepubertal (serum progesterone < 500 pg/mL) were fitted with surgically implanted jugular catheters. Blood samples were drawn at 1100 (4 h after onset of light), 1130, 1200, 2300 (4 h after onset of darkness), 2330, and 2400 for 4 d. On d 5 of sampling, gilts were transported in an open-bed truck for 15 min, returned to their original environment, and exposed to boars for 20 min. Boar exposure was repeated every day throughout the remainder of the experimental period. Blood samples were drawn from each gilt until 7 d after estrus or for 12 d in those gilts that did not exhibit estrus. Blood samples were drawn by venipuncture from the ewes during the entire experimental period. For each sampling day, within an individual gilt or ewe, means of serum concentrations of melatonin (MEL) for night (scotophase) and day (photophase) samples were calculated. After three replications were conducted, four classes of animals were obtained: ewes (n = 9); nonpubertal gilts (n = 10); and two classes of gilts that ultimately reached puberty (prepubertal [n = 16] and postpubertal [n = 16]). Across all gilts, only 65 of 406 bleeding periods (16.0%) had a nocturnal (scotophase) rise in serum MEL. The proportion of gilts expressing a nocturnal rise in serum MEL did not differ as gilts approached puberty (P > .05). Incidence of nocturnal rises of MEL was similar (P > .05) in gilts that attained puberty and gilts that did not attain puberty. Nocturnal rises in MEL were observed in 86.2% of the bleeding periods of ewes housed in the same environment. These data indicate clearly that nocturnal rises in serum MEL are not necessary for a gilt to attain puberty.

Failure of melatonin implants to alter onset of puberty in gilts

Forty crossbred gilts (Hampshire x Yorkshire x Landrace x Duroc) weighing 55.4 +/- 0.5 kg at 4.2 +/- 0.1 months of age received either melatonin implants (N = 20) or served as controls (N = 20). Gilts were housed in a temperature controlled room (21 degrees C) with a light (L):dark (D) cycle of 10L:14D. Initially, four implants (12 mg melatonin each, Wildlife Pharmaceuticals, Ft. Collins, CO) were placed in one ear subcutaneously. At 2-week intervals, five, six, seven or eight implants were placed in ears of the gilts (one implant per 11.8 kg body weight). Throughout the trial, blood samples were collected twice weekly by jugular venipuncture. All gilts were exposed to mature boars for 15 min on alternate days. Age of puberty was determined from serum concentrations of progesterone and visual observations of estrus. Serum concentrations of melatonin were elevated (5-10 fold) throughout the trial in those gilts that received melatonin implants. Average daily gain (P = 0.51) and age at puberty (P = 0.57) were similar between gilts that received melatonin implants or no implants. Even though gilts continued to receive melatonin after they attained puberty, elevated serum concentrations of melatonin did not alter the length of subsequent estrous cycles (P = 0.90). These data indicate that elevation of serum concentrations of melatonin via implants did not alter the onset of puberty or length of subsequent estrous cycles.

Is experience a good teacher? How interns and attending physicians understand patients' choices for end-of-life care. SUPPORT Investigators. Study to Understand Prognoses and Preferences for Outcomes and Risks of Treatments

BACKGROUND

Recent studies have shown that physicians do not accurately assess patients' health status or treatment preferences. Little is known, however, about how physicians' levels of training or experience relate to their abilities to assess these preferences. To better understand this phenomenon, the authors compared the abilities of medical interns and attending physicians to predict the choices of their adult patients for end-of-life care.

METHODS

230 seriously-ill adult inpatients were surveyed about their desires for cardiopulmonary resuscitation, their current quality of life, and their attitudes toward six other common adverse outcomes. The medical intern and attending physician who cared for these patients were asked to estimate the patient's responses for all of the same items. Agreement was assessed using the kappa statistic.

RESULTS

Compared with interns, attending physicians had known patients longer, had talked with patients more frequently about prognosis, and felt they knew more about their patients' preferences (all p < .0001). Despite this, the attending physicians were no more accurate than the interns in assessing patients' preferences. Both interns and attending physicians had only a fair understanding of patients' preferences for cardiopulmonary resuscitation or their quality of life (kappa statistics 0.32 to 0.47), and even less understanding of their willingness to tolerate adverse outcomes (kappa statistics -0.03 to 0.37).

CONCLUSIONS

For this cohort of seriously ill patients, neither medical interns nor their attending physicians were consistently accurate in assessing patients' preferences, and attending physicians were not more accurate than medical interns. Attending physicians should not assume that they can infer patients' preferences any better than the interns caring for these hospitalized patients.

Serum concentrations of melatonin in prepubertal or postpubertal gilts exposed to artificial lighting or sunlight

To determine if the type of environmental lighting or reproductive status influences secretory patterns of serum melatonin, gilts were exposed to artificial light or full sunlight during the summer months. In Experiment 1, eight prepubertal and eight postpubertal gilts (Hampshire x Yorkshire x Duroc) were exposed to light intensity of 700 lux in an environmentally controlled room from 0730 to 1900 h daily. An additional eight prepubertal and eight postpubertal gilts were reared outdoors in an open modified-front gestation building and fed on a concrete apron outdoors where light intensity approached 50,000 lux in full sunlight. After 2 mo of acclimating to these environmental conditions, blood samples were drawn from each gilt at 2-h intervals from 1000 to 0200 h. Serum concentrations of melatonin were assayed utilizing Guildhay antisera. The experiment was repeated during the same months of the following year utilizing different gilts (Experiment 2). During both replications, neither light intensity nor reproductive status affected the secretory patterns of melatonin during the sampling period (P >0.05). In both prepubertal and postpubertal gilts, serum concentrations of melatonin were not reduced (P >0.05) by exposure to direct sunlight. Since baseline concentrations of serum melatonin were not reduced by sunlight during the day, the incidence of nocturnal rises of melatonin was not increased (P >0.05) in either prepubertal or postpubertal gilts.

Molecular cloning of spermidine/spermine N1-acetyltransferase from the periimplantation porcine uterus by messenger ribonucleic acid differential display: temporal and conceptus-modulated gene expression

Using messenger RNA (mRNA) differential display, we isolated several putative differentially expressed complementary DNAs (cDNAs) from the periimplantation (days 11-12) endometrium of unilaterally pregnant pigs. Nucleotide sequence analysis revealed that one cDNA clone was 87% homologous to human spermidine/ spermine N1-acetyltransferase (SSAT) over a stretch of 201 bp and represents the porcine homologue of this cDNA. A second differentially expressed cDNA encoded the porcine equivalent of the human fragile X mental retardation gene (FMR1), whereas a third specified an open reading frame with significant homology to the Escherichia coli N-acetylglucosamine transfer protein. Because SSAT is the rate-limiting enzyme in polyamine metabolism and polyamines are required cytosolic components for cell growth and differentiation, we characterized the expression of the porcine SSAT gene as a potential marker for endometrial growth and/or differentiation during early pregnancy. Further, using the consensus sequence from human and mouse cDNAs, PCR primers were designed and used to generate a 568-bp cDNA fragment from gravid endometrium that encompassed the entire open reading frame for porcine SSAT and which was subsequently used for Northern hybridization analysis. Two distinct SSAT transcripts, a major species of 1.3 kilobase pairs (kb) and a minor species of 3.5 kb were detected in endometrium, each with similar temporal patterns of expression. The levels of SSAT mRNA were higher (P = 0.03) in gravid than in nongravid uterine endometrium of unilaterally pregnant pigs on days 11-12. Similarly, SSAT mRNAs were more abundant (P = 0.0004) in day 12 pregnant than in day 12 cyclic, and in days 30, 60, 90, and 105 pregnant pig endometria. Uterine endometrial luminal epithelial (LE), glandular epithelial (GE), and stromal (ST) cells expressed the SSAT gene, but mRNA abundance varied among cell types (LE > GE > ST). Expression of SSAT gene in ovariectomized gilts treated with estrogen (E2, 100 microg/day), progesterone (P4, 200 mg/day) or E2 + P4 for 11 days was highest (P = 0.03) in the endometria of the P4 group. In contrast, E2 (10 nM), P4 (10 nM) and E2 + P4 had no effect on SSAT mRNA abundance in uterine endometrial explants from day 12 pregnant pigs. However, steady-state SSAT mRNA levels were induced in day 12 pregnant uterine explants by conditioned medium from day 12 filamentous but not spherical conceptuses. These data demonstrate that the temporal induction of the endometrial SSAT gene during periimplantation is modulated by a factor(s) secreted by the periimplantation conceptus and suggest that this enzyme may have an important role in uterine endometrial growth, remodeling and/or differentiation during periimplantation.

Selective self-stereotyping

In an examination of group members' responses to the threat of negative in-group characterizations, sorority/fraternity members were asked to rate themselves, their own sorority/fraternity, sororities/ fraternities in general, and students in general on attributes that were stereotypic of sororities/ fraternities. Results showed that individuals selectively self-stereotyped-they embraced positive stereotypes as highly descriptive of themselves and their closest in-groups but rejected negative stereotypes. They did not, however, deny that negative stereotypes were accurate or valid-they continued to accept them as typical of sororities/fraternities in general. This represents a protective, creative response to the threat posed by exposure to negative group attributes, in which self-stereotyping as a result of self-categorization is selective rather than complete.

Cognitive functioning and posttraumatic stress disorder

OBJECTIVE

The authors examined the association of cognitive impairment with posttraumatic stress disorder (PTSD) and other psychiatric diagnoses known to affect cognitive functioning.

METHOD

The results of standardized neuropsychological tests were compared in four groups of Vietnam veterans: veterans with both a lifetime history of PTSD and a current diagnosis of depression, anxiety, or substance abuse; veterans with only a PTSD diagnosis; veterans with only a current diagnosis of depression, anxiety, or substance abuse; and veterans with none of these diagnoses.

RESULTS

Veterans with both PTSD and concurrent diagnoses. exhibited more impairment in cognitive functioning than did veterans without these diagnoses.

CONCLUSIONS

Cognitive deficits seen among persons diagnosed with PTSD may be associated with their concomitant diagnoses.

The unique endometrial expression and genomic organization of the porcine IGFBP-2 gene

The insulin-like growth factor-binding proteins (IGFBPs-1-6) modulate the mitogenic and differentiative actions of the IGFs and may have IGF-independent functions. This study examined the gene expression and pregnancy-regulation of the IGF/IGFBP system in porcine uterine endometrium and myometrium during the periimplantation period and later stages of pregnancy. Endometrial IGFBP-2 mRNA abundance exhibited stage of pregnancy-dependent induction; whereas little or no IGFBP-2 mRNA was found in myometrium. IGFBP-2 protein was immunolocalized to the endometrial glandular and luminal epithelia (staining on day 60 > day 12) with minimal or no immunostaining of uterine stroma observed. IGFBP-3 and IGFBP-4 transcript levels became elevated in endometrium after implantation; whereas, IGFBP-5 and IGFBP-6 mRNAs were in greater abundance in periimplantation than post-implantation endometrium. IGFBP-1 transcripts, in contrast, could not be identified in porcine endometrium or myometrium of pregnancy. As a pre-requisite to understanding the pregnancy-induction and endometrial-specificity of the uterine-expressed IGFBP-2 gene, cosmids encompassing the pig IGFBP-2 chromosomal locus were isolated and characterized. This gene is comprised of four exons that span > 29 kb and encode a 316 amino acid precursor protein. All four exons were found to be G/C rich with exon 1 and immediate 5' flank exhibiting hallmarks of a CpG island. This latter region was devoid of TATA and CAAT motifs. Results identify the preferential endometrial expression of different IGFBP genes at either the periimplantation or post-implantation periods, perhaps reflecting distinct actions of these proteins at the embryo-maternal and feto-maternal interfaces, respectively. Interactions of steroid receptors, endometrial transcription factors and their corresponding cis elements may confer the unique uterine expression of the IGFBP-2 gene.

Serum concentrations of melatonin in prepubertal gilts exposed to either constant or stepwise biweekly alteration in scotophase

Melatonin (MEL), a hormone known to mediate photoperiodic cues, is secreted from the pineal gland in a circadian fashion in numerous species. The transduction of photoperiodic information into the secretion of MEL, however, remains controversial in the pig. To determine whether domestic pigs have a nocturnal increase in serum melatonin when exposed to equatorial photoperiods only, 24 prepubertal gilts (38.7 +/- 0.7 kg; 104.5 +/- 0.8 d) and 12 mature ewes, serving as positive controls, were randomly assigned to one of two environmentally regulated rooms. The light (L):dark (D) schedule in one room remained constant (10 L:14 D), while the other room scotophase (darkness duration) was decreased by 1 hr every 2 wk (Experiment 1). After a 2-wk acclimation to each new schedule, 6 ewes and 6 gilts in each room were bled by venipuncture at 2-hr intervals for 22 hr. Experiment 2 was conducted as described for Experiment 1, except that the LD schedule in one room remained constant (15L:9D) while length of scotophase in the other room was increased by 1 hr every 2 wk. In gilts that were exposed to constant 10L:14D, scotophase MEL in serum averaged 103 +/- 13 pg/ml as compared with 57 +/- 13 pg/ml in the photophase. Using each gilt's initial photophase value as a statistical covariate, scotophase MEL in the constant 10L:14D schedule was higher (P < 0.001) than photophase MEL. A similar analysis of MEL in gilts exposed to stepwise biweekly decreases in scotophase revealed a scotophase elevation (P < 0.05) in only certain LD schedules (i.e., 12L:12D and 13L:11D), but the same trend was present throughout all LD schedules. Subjective examination of individual gilt profiles revealed that 56% of gilts had a nocturnal increase in serum MEL in Experiment 1. However, only 10% of the MEL profiles were closely coupled to the environmental LD periods. Overall, mean serum MEL in gilts was of lesser magnitude and more variable than in ewes. Data from these two experiments suggests that the domestic pig has an inherently weak nocturnal elevation in serum MEL, and the ability to detect these rises is dampened by considerable pig-to-pig variability.

Developmental regulation of steroidogenic enzyme gene expression in the periimplantation porcine conceptus: a paracrine role for insulin-like growth factor-I

During periimplantation, the estrogen biosynthetic capability of the porcine conceptus is transient, coincident with morphological development (trophoblast elongation), and temporally associated with maximal uterine release of insulin-like growth factor-I (IGF-I) into the luminal fluid. We investigated the possible linkages of conceptus steroidogenesis and IGF-I by characterizing the developmental expression of the pig conceptus cytochrome P450 aromatase (P450arom) and cytochrome P450 17 alpha-hydroxylase (P45017 alpha) genes during periimplantation (days 8, 10, 12, 15, and 18) and the potential regulation by IGF-I of conceptus P450arom messenger RNA (mRNA) content. Primer pairs derived from porcine P450arom and P45017 alpha DNA sequences were used in reverse transcription-polymerase chain reaction analysis of conceptuses of differing morphologies and developmental stages. RNA transcripts for P450arom and P45017 alpha were readily detected only in conceptuses obtained at day 12 of pregnancy, with RNA levels varying according to morphological stage. P45017 alpha gene expression was maximal in spherical conceptuses greater than 5 mm in diameter, whereas P450arom mRNA was expressed in small (3-5 mm) and large (6-10 mm) spherical (large >> small), as well as day 12, filamentous conceptuses. Using primers derived from the human IGF-I receptor (IGF-IR) DNA sequence, constitutive expression of IGF-IR mRNA in porcine conceptuses throughout early pregnancy was demonstrated. Constitutively low expression of conceptus RNA transcripts for IGF-I ligand was similarly observed. However, uterine luminal fluid concentrations of IGF-I on day 12 were highly correlated with conceptus morphology, with maximal IGF-I in uteri possessing filamentous conceptuses. In vitro addition of IGF-I to day 12 conceptuses of filamentous or spherical morphologies resulted in distinct effects on P450arom mRNA abundance. Filamentous conceptuses had increased amounts of P450arom mRNA when treated with IGF-I. In contrast, IGF-I decreased the levels of P450arom mRNA in spherical conceptuses. IGF-I treatment did not alter mRNA expression of the IGF-IR gene in conceptuses of either morphology. These results demonstrate that transient expression of P450arom and P45017 alpha genes in perimplantation porcine conceptuses, document the constitutive expression of the conceptus IGF-IR gene, and support the involvement of endometrial IGF-I in modulation of embryonic P450arom mRNA abundance.

Health values of the seriously ill. SUPPORT investigators

OBJECTIVE

To assess 1) the health values and health ratings of seriously ill hospitalized patients, their surrogate decision makers, and their physicians; 2) the determinants of health values; and 3) whether health values change over time.

DESIGN

Prospective, longitudinal, multicenter study.

SETTING

5 academic medical centers.

PARTICIPANTS

1438 seriously ill patients with at least one of nine diseases who had a projected overall 6-month mortality rate of 50%; their surrogates; and their physicians.

MEASUREMENTS

Time-tradeoff utilities (reflecting preferences for a shorter but healthy life) and health ratings.

RESULTS

At study day 3, patients had a mean time-tradeoff utility of 0.73 +/- 0.32 (median [25th, 75th percentile], 0.92 [0.63, 1.0]), indicating that they equated living 1 year in their current state of health with living 8.8 months in excellent health. However, scores varied widely; 34.8% of patients were unwilling to exchange any time in their current state of health for a shorter life in excellent health (utility, 1.0), and 9.0% were willing to live 2 weeks or less in excellent health rather than 1 year in their current state of health (utility, 0.04). Health rating scores averaged 57.8 +/- 24.0 (median [25th percentile, 75th percentile], 60 [50, 75]) on a scale of 0 (death) to 100 (perfect health). The patients' mean time-tradeoff score exceeded that of their paired surrogates (n = 1041) by 0.08 (P < 0.0001). Time-tradeoff scores were related to psychosocial well-being; health ratings; desire for resuscitation and extension of life rather than relief of pain and discomfort; degree of willingness to live with constant pain; and perceived prognosis for survival and independent functioning. Scores of surviving patients increased by an average of 0.06 after 2 months (P < 0.0001) and 0.08 after 6 months (P < 0.0001).

CONCLUSIONS

Health values of seriously ill patients vary widely, are higher than patients' surrogates believe, are related to few other preference and health status measures, and increase over time.

Transient expression of the cytochrome P450 aromatase gene in elongating porcine blastocysts is correlated with uterine insulin-like growth factor levels during peri-implantation development

The insulin-like growth factors (IGFs-I and -II) are mediators of cellular growth and differentiation. The expression of these growth factor genes is temporally and hormonally regulated in the uterus during pregnancy, suggesting potentially important roles in embryonic development, implantation, and successful progression of pregnancy. A known regulator of uterine IGF-I secretion is estrogen, which is produced by pre-implantation mammalian embryos of several species and whose amounts may be influenced by growth factors via their effects on the transcriptional activities of steroidogenic enzyme genes. We have previously proposed that within the uterine microenvironment, a positive feedback loop may link uterine secretion of IGFs with embryonic production of estrogens to maintain and coordinate the timing of biological signals essential for embryo development. The present study examined the temporal relationships between the levels of conceptus cytochrome P450 aromatase mRNA and protein and concentrations of IGF-I and -II in uterine luminal fluids of pigs. A DNA fragment encoding a highly conserved region among mammalian aromatase P450 proteins was isolated by hybridization screening of a porcine genomic DNA library with a human aromatase P450 cDNA fragment as probe. A synthetic oligopeptide DDVIDGYPVKKGTNI within this highly conserved region was used to generate an antiserum in sheep that recognized a protein of M(r) 49,000 in Western blot analysis of porcine ovarian, placental, endometrial, and conceptus extracts. A radioimmunoassay (RIA) for aromatase P450 was established and validated using this antiserum. RIA demonstrated highest levels of aromatase P450 protein in extracts of days 10, 11, and 12 porcine conceptuses with significantly diminished levels in elongated conceptuses at days 15 and 18. In the conceptus, aromatase P450 was localized to the inner cell layer (hypoblast) of the trophectoderm. A major mRNA transcript of approximately 3 kb in length was demonstrated by Northern blot analysis of conceptus RNA with a porcine aromatase P450 antisense RNA probe. The relative levels of aromatase P450 mRNA were higher in conceptuses at day 12 than at days 15 and 18, in parallel with the levels of aromatase P450 protein. RIA of uterine luminal fluids demonstrated maximal concentrations of IGF-I at day 12, which were significantly decreased by day 15, and increased concentrations of IGF-II by day 12, which were maintained until day 18 of pregnancy. These results demonstrate that the transient expression of conceptus aromatase P450 mRNA and protein in elongating pig blastocysts is coincident with their capacity to secrete estrogens and with the rapidly changing concentrations of IGFs within the uterine microenvironment.(ABSTRACT TRUNCATED AT 400 WORDS)

Growth and reproductive performance, during exposure to ammonia, of gilts afflicted with pneumonia and atrophic rhinitis

From 2 to 4.5 months of age, 80 crossbred gilts were reared in a conventional grower unit where they were naturally exposed to mycoplasmal and bacterial pathogens that cause pneumonia and atrophic rhinitis. At 4.5 months of age, gilts were moved to environmentally regulated rooms (4.9 x 7.3 m) and assigned at random to 1 of 2 treatment groups: low aerial concentration of ammonia (4 to 12 ppm; mean, 7 ppm) or moderate aerial concentration of ammonia (26 to 45 ppm, mean, 35 ppm). Low concentration of ammonia was obtained by flushing of manure pits weekly, whereas moderate concentration of ammonia was maintained by adding anhydrous ammonia to manure pits that were not flushed. Gilts were weighed biweekly. Mean daily gain (MDG) was less (P < 0.01) for gilts exposed to moderate concentration of ammonia than for gilts exposed to low concentration of ammonia after 2 weeks in their respective environments. By 4 and 6 weeks, however, MDG was similar between the 2 treatment groups. After 6 weeks in these environments, 20 gilts from each treatment group were slaughtered, and prevalence and severity of lung lesions and snout grades were determined. At slaughter, body weight was greater (P < 0.01) in gilts exposed to low, rather than moderate, ammonia concentration (94.5 vs 86.8 kg; SEM, 3.3 kg). Percentage of lung tissue containing lesions (18 vs 12) and snout grade (2.8 vs 3.1) were similar between gilts exposed to low or moderate concentration of ammonia. The remaining 20 gilts in each treatment group were maintained in their respective environments, exposed daily to mature boars and bred at first estrus.(ABSTRACT TRUNCATED AT 250 WORDS)

Serum concentrations of immunoactive and bioactive luteinizing hormone (LH) in gilts. II. Biopotency of LH increases at puberty but remains constant throughout the estrous cycle

To determine serum concentrations of immunoactive (I) and bioactive (B) LH during the pubertal surge of LH release, two groups of twelve prepubertal gilts were relocated and exposed to boars to stimulate the onset of puberty. Puberty was defined as the first sign of behavioral estrus and occurrence of a preovulatory surge of LH. Blood samples were taken every 2 h, beginning on the third or fifth day after boar exposure; sampling was continued for 24 h after each gilt had exhibited estrus, or for 7 days, or until two-thirds of the gilts in a group attained puberty. Fifty percent of the total number of gilts exposed to boars attained puberty within 7 days of first boar exposure. Total area under the ILH curve was greater (p < 0.01) than area under the BLH curve during the ovulatory rise in LH. A second experiment was conducted to compare serum concentrations of ILH and BLH during the luteal and follicular phases of the estrous cycle. Blood samples were collected every 20 min for a 6-h period of spontaneous secretion; then GnRH was injected and blood samples were collected every 20 min for 4 h from gilts during the luteal (n = 16) and follicular (n = 15) phases, respectively. BLH baseline tended to be greater (p = 0.07) during the follicular phase than during the luteal phase. Mean peak amplitude of naturally occurring peaks of ILH and BLH was greater (p < 0.05) during the luteal phase than during the follicular phase.(ABSTRACT TRUNCATED AT 250 WORDS)

Serum concentrations of immunoactive and bioactive luteinizing hormone (LH) in gilts. I. Biopotency of LH increases during prepubertal development

The patterns of secretion of bioactive and immunoactive LH during prepubertal development were examined in four groups of 12 gilts each at approximately 3, 4, 5, and 6 mo of age. The rat interstitial cell testosterone assay was validated for the determination of bioactive LH (BLH) in porcine serum. Serum concentrations of immunoactive LH (ILH) were determined by RIA. Blood samples were collected via indwelling jugular catheters every 20 min for a 6-h period of spontaneous secretion. GnRH (0.5 microgram/kg BW) was injected i.v. and blood samples were taken for an additional 4 h at 20-min intervals. Mean serum and baseline concentrations of ILH and of BLH were greater (p < 0.05) in 3-mo-old gilts than in gilts of other ages. Three-month-old gilts also secreted more ILH and more BLH in response to GnRH than 6-mo-old gilts (p < 0.05), but the biopotency of GnRH-induced LH was reduced (p < 0.05) in 3-mo-old gilts. Elevated serum concentrations of ILH and of BLH in 3-mo-old gilts may be inherently necessary to give follicles the maximum opportunity to respond to LH. During the period of prepubertal development, estimates of ILH accurately reflected BLH concentrations except when LH release was stimulated by exogenous GnRH. The age-related increase observed in the biopotency of LH released in response to GnRH may reflect a maturational process whereby the biopotency of LH increases as gilts approach puberty.

Influence of porcine somatotropin on endocrine and histological variables in gilts

Thirty-six crossbred gilts (71.7 +/- .9 kg and 140.1 +/- .9 d) were assigned to one of three doses (0, 35, or 70 micrograms.kg BW-1 x d-1) of recombinant porcine somatotropin (rpST). The doses of rpST were adjusted weekly, and i.m. injections continued until d 50. Gilts were pen fed (six gilts/pen) a 17% CP corn-soybean diet (1.2% lysine and 3.2 Mcal of ME/kg). At d 50, feed intake, feed:gain ratios (P = .02), and blood urea nitrogen were decreased (P < .001) by increasing rpST doses, whereas ADG was increased (P = .04) by increasing rpST doses. Injections of rpST did not affect (P > .05) conception rate, age, or weight at puberty. Numbers of blastocysts or corpora lutea observed at d 10.4 +/- 1.5 of gestation (42.2 d after final rpST injection) were unaffected (P > .05) by rpST treatment. Anterior and posterior pituitary weights were increased (P < or = .003) linearly with rpST dose. However, liver, adrenal, and heart weights were unaffected (P > .05) by rpST. After a withdrawal period of 42.2 +/- 2.0 d, rpST increased (P < or = .02) the estimated percentage of lean by 5.8% and longissimus muscle area by 10.4%. Eighteen hours before the initial rpST injection (d 0), 10 gilts per rpST dose were catheterized. Catheterizations were repeated on d 40. The rpST or diluent was given i.m. in the extensor muscle of the neck 1 h after initiation of blood collection. Adrenocorticotropic hormone (1.4 IU/kg BW) was administered through the catheter 3 h after initiation of blood collection.(ABSTRACT TRUNCATED AT 250 WORDS)

Mycotoxins and reproduction in domestic livestock

Molds are parasitic plants that are ubiquitous in livestock feedstuffs. Even though molds themselves reduce the quality of grains, their synthesis of chemical substances termed mycotoxins causes the greatest monetary loss to the animal industry. Five major mycotoxins that impair growth and reproductive efficiency in North America are aflatoxins, zearalenone, deoxynivalenol, ochratoxin, and ergot. Aflatoxins are produced by Aspergillus flavus and Aspergillus parasiticus. Consumption of grains containing aflatoxins by swine affects reproduction indirectly by reducing feed intake and growth. In swine, aflatoxins impair liver and kidney function, delay blood clotting, increase susceptibility to bruising, and interfere with cellular humoral immune systems. Ruminants are comparatively resistant to aflatoxicosis, but presence of aflatoxins in milk of dairy cows is closely monitored for human safety. Depending on environmental conditions, Fusarium roseum can produce either zearalenone or deoxynivalenol. Days 7 to 10 postmating seem to be a critical period of gestation for zearalenone to exert its detrimental actions on early embryonic development. Presence of deoxynivalenol in swine feedstuffs decreases feed intake, causes feed refusal, and induces occasional vomiting. Several species of Penicillium and Aspergillus produce ochratoxin, a mycotoxin that causes necrosis of kidney tissue. Ergot alkaloids produced by Claviceps purpurea on wheat can cause reproductive problems and are associated with lactational failure in swine. Various methods have been developed to remove mycotoxins from infected feedstuffs. Chemical analyses in laboratories as well as diagnostic kits suitable for use at the elevator or farm can be used successfully to identify which mycotoxins are present in suspect feedstuffs.

Lack of a nocturnal rise of serum melatonin in prepubertal gilts

Experiments were conducted to determine if a nocturnal rise in serum melatonin occurs in prepubertal gilts and whether acute exposure of gilts to light during the dark period abruptly reduces serum concentrations of melatonin. In experiment 1, 12 prepubertal crossbred gilts (Duroc x Hampshire x Chester White x Yorkshire) weighing 96.4 + 1.3 kg at 5.1 + .1 mo of age were housed in an LD cycle of 10:14. Following a 3-wk acclimation period, blood samples were drawn at 1-hr intervals from indwelling jugular catheters. Serum concentrations of melatonin were similar (P greater than .05) among blood samples collected during light and dark periods. In experiment 2, serum concentrations of melatonin did not change (P greater than .05) when gilts were abruptly exposed to light during the normal dark period. In experiment 3, serum concentrations of melatonin were similar (P greater than .05) in blood samples collected at 2-hr intervals under 700 lux of light or in total darkness from gilts maintained in either LD 9:15 or LD 24:0. Data from experiment 4 demonstrated that serum melatonin could be detected in nighttime samples if exogenous melatonin was ingested by gilts at night. Together, these experiments clearly indicate that prepubertal gilts do not exhibit a nocturnal rise in serum melatonin when maintained under short daylengths (10L:14D or 9L:15D), and serum melatonin concentrations are unaffected by abrupt changes in light/dark conditions.

Evaluation of use of progesterone to counteract zearalenone toxicosis during early pregnancy in gilts

It has been shown that zearalenone disrupts early pregnancy in swine without altering intrauterine content of estradiol 17 beta or progesterone, embryo migration, or estradiol-17 beta synthesis by blastocysts. However, serum concentrations of progesterone were reduced 2 to 3 weeks after mating in gilts that ingested zearalenone. Therefore, progesterone was administered to gilts during early pregnancy to determine whether it could counteract the detrimental actions of zearalenone on embryonic development. Thirty-two crossbred gilts (Hampshire x Chester White x Yorkshire x Duroc) were assigned randomly to a 2 x 2 factorial arrangement of treatments: zearalenone (Z); zearalenone plus progesterone (ZP); progesterone (P); or control (C). From postmating days 4 to 15, Z- and ZP-treated gilts were fed 1 mg of Z/kg of body weight, and P-treated and C gilts were fed ethanol as vehicle in a corn-soybean diet. On postmating days 3 to 15, P- and ZP-treated gilts were injected IM with 100 mg of progesterone, and C and Z-treated gilts were injected with progesterone carrier (15% ethanol, 15% benzyl alcohol, 70% propylene glycol). Blood was collected from gilts by puncture of the jugular vein daily from days 3 to 15, on alternate days from days 17 to 31, and then twice weekly until the end of the experiment. Fetal development was assessed in Z- and ZP-treated gilts on postmating day 47.6 +/- 2.9 by cesarean section and in P-treated and C gilts at slaughter on postmating days 51.2 +/- 3.2. Serum concentrations of progesterone in P-treated gilts were greater on days 7 to 8, 10 to 15, 17, and 19 than in C gilts. Serum concentrations of progesterone were greater on days 8, 10, and 12 in ZP-treated than in C gilts. However, serum concentrations of progesterone were lower in ZP-treated gilts than in C gilts on postmating days 19 to 31.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of sampling interval on serum concentrations of luteinizing hormone, follicle-stimulating hormone, and prolactin in prepubertal, ovariectomized, and cycling gilts

Three experiments were conducted to determine the effect of sampling interval on serum concentrations of LH, FSH, and prolactin (PRL) in prepubertal, ovariectomized, and cycling gilts. In all experiments, blood samples were drawn at 2-min intervals for 4 h from indwelling jugular catheters. Mean serum hormone concentrations, mean number of peaks, and mean and maximum peak heights of LH, FSH, and PRL were calculated using values reflecting 2-, 6-, 10-, 20-, 30-, and 60-min sampling intervals. For LH, FSH, and PRL, mean serum concentrations can be obtained through blood samples drawn at hourly intervals. Since LH peaks are very distinct in pigs, the number of secretory peaks and mean peak height can be obtained via samples drawn at 20-min intervals. Since FSH and PRL peaks are less well defined, a more frequent sampling interval (10 min) is needed to determine number of peaks and mean peak height. To obtain the maximum peak height or the number of minutes for LH, FSH, or PRL to rise from its nadir to zenith, blood samples need to be drawn at 2-min intervals. Regardless of reproductive state, these data indicate that the sampling interval needed to characterize serum concentrations of LH, FSH, and PRL in the gilt is dependent upon the parameter in question.

Influence of daily injections of porcine somatotropin on growth, puberty, and reproduction in gilts

To determine whether recombinant porcine somatotropin (rpST) alters reproduction, 40 crossbred gilts weighing 59.1 +/- .5 kg at 125 +/- 1 d of age were assigned randomly to an experiment arranged as a 2 x 2 factorial. Eight gilts were given daily injections of diluent until they reached 104 kg BW (DW), and eight received diluent injections until puberty (DP). Twelve gilts were given rpST (4 mg/d) until 104 kg BW (PW) and 12 were given rpST injections until puberty (PP). All gilts were individually fed on an ad libitum basis an 18% CP corn-soybean meal diet (1.2% lysine and 3.1 Mcal/kg of ME). Beginning at 5 mo of age, gilts were exposed 20 min daily to mature boars. Serum concentrations of progesterone were measured weekly from 5 to 8 mo of age to verify age of puberty. Gilts observed in pubertal estrus were mated to two different boars 10 h apart. At 47 +/- 1 d of gestation, gilts were slaughtered to assess fetal development. After 60 d of treatment, serum LH and FSH profiles were determined in blood samples drawn at 20-min intervals for 4 h from eight diluent- and eight rpST-treated gilts fitted with indwelling jugular catheters. By 28 d, feed intake, feed/gain, and blood urea nitrogen were decreased (P less than .005) by rpST. Treatments did not affect (P greater than .05) the proportion of gilts attaining first ovulation (DW = 6/6; DP = 10/10; PW = 7/9; PP = 14/14) or conception rate (DW = 5/6; DP = 7/10; PW = 4/6; PP = 11/12).(ABSTRACT TRUNCATED AT 250 WORDS)

Reduction in age of puberty in gilts consuming melatonin during decreasing or increasing daylength

Two experiments were conducted to determine whether oral administration of melatonin alters the onset of puberty in gilts during naturally increasing or decreasing daylength. In Exp. 1, 20 crossbred prepubertal gilts weighing 77.5 +/- .5 kg at 171.8 +/- 1.0 d of age were assigned randomly to receive either a daily oral dose of 3 mg of melatonin (MEL) or ethanol vehicle (ETH) at 1530 from August 31 to December 1, 1987 (decreasing daylength). Gilts were exposed to mature boars for 20 min thrice weekly and blood samples were collected twice weekly. Serum concentrations of progesterone were used to establish age at puberty and length of estrous cycle. In Exp. 2, 20 crossbred prepubertal gilts weighing 67.7 +/- .7 kg at 143.8 +/- 1.1 d of age received either MEL or ETH treatment from February 1 to May 15, 1988 (increasing daylength). Age of puberty was less in gilts that received MEL than in gilts that received ETH in both Exp. 1 (198 +/- 3 vs 228 +/- 7 d; P less than .01) and Exp. 2 (183.8 +/- 2.7 d vs 194.3 +/- 3.3 d; P less than .05). Gilts that received MEL reached puberty at a lighter weight than gilts that received ETH in Exp. 1 (95.6 +/- 2.1 vs 112.4 +/- 3.9 kg; P less than .01) and Exp. 2 (88.1 +/- 1.5 vs 96.0 +/- 1.8 kg; P less than .01). Serum concentrations of LH and FSH, length of estrous cycles, and percentage of muscle of carcasses were similar between MEL and ETH gilts.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of vascular cannulation on serum concentrations of LH, FSH, prolactin and cortisol in prepubertal gilts

Two experiments were conducted to determine whether cannulation of the jugular vein in gilts alters serum concentrations of LH, FSH, prolactin (PRL) or cortisol (C). In Experiment 1, 12 crossbred prepubertal gilts weighing 95 +/- 1.3 kg were immobilized by snaring, and tygon tubing was threaded into the anterior vena cava through a 12-gauge needle inserted into the jugular vein. Five hours later, blood samples were drawn at 20-min intervals for 4 h (Day 0). Samples were also drawn at 20-min intervals for 4-h periods 24 h (Day 1) and 48 h (Day 2) after cannulation. Serum concentrations of LH were similar (P=0.26) among Day 0 (0.40 ng/ml), Day 1 (0.39 ng/ml) and Day 2 (0.34 ng/ml). Serum PRL was similar (P=0.07) among Day 0 (4.10 ng/ml), Day 1 (3.87 ng/ml) and Day 2 (3.43 ng/ml). Serum concentrations of C were greater (P < 0.001) on Day 0 (8.32 ng/ml) than Day 1 (4.48 ng/ml) or Day 2 (3.54 ng/ml). In Experiment 2, cannulas were placed in 29 prepubertal gilts. Two days after initial cannulation, six blood samples were drawn at 20-min intervals. Gilts were then immobilized by snaring, and a second cannulae was inserted into the contralateral vein. Five blood samples were taken at 2-min intervals during the second cannulation and then six samples were drawn at 20-min intervals. Serum LH and FSH were not altered by cannulation or elevated during the subsequent 2-h sampling period (P>0.05). In contrast, serum concentrations of PRL rose slowly (P<0.05) during cannulation and remained elevated for 60 min before returning to baseline. Serum concentrations of C rose within 6 min of cannulation, remained elevated for 30 min, and then declined over the next 90 min. From these two experiments, it appears that secretory patterns of LH and FSH can be accurately assessed immediately after cannulation in prepubertal gilts. Measurements of serum PRL and C that reflect nonstressed conditions, however, cannot be obtained until at least 2 h or 1 d after cannulation, respectively.

Effect of prepubertal consumption of zearalenone on puberty and subsequent reproduction of gilts

Forty-eight prepubertal gilts (178.7 +/- 4.1 d; 94.2 +/- 4.1 kg), 16 in each of three trials, were assigned randomly to receive 0 (C) or 10 ppm zearalenone (Z) daily in 2.5 kg of a 14% protein finishing ration for 2 wk. Blood samples were collected at 20-min intervals for 4 h 1 wk after the start of the experiment and 1 wk after Z was withdrawn. Two weeks after Z was withdrawn, gilts were exposed to mature boars 15 min per day for 3 wk. Gilts in estrus were mated to two different boars 12 h apart. Twice each week, blood was sampled and analyzed for progesterone to establish age of puberty. Age at puberty differed (P = .008) among replicates but was similar (P = .13) between Z and C gilts within each replicate. Mean serum concentrations of LH were suppressed (P = .025) during consumption of Z (.25 vs .42 ng/ml) but were similar (P = .16) to concentrations in C gilts 1 wk after Z was withdrawn (.35 vs .45 ng/ml). Frequency and amplitude of LH secretory spikes did not differ (P greater than .50) between Z and C gilts during either sampling period. Mean serum concentrations of FSH were similar (P = .25) between Z and C gilts. Number of corpora lutea and live fetuses were similar (P = .29 and P = .94, respectively) between Z and C gilts. Fetal weights were greater (P = .025) and crown to rump length tended to be greater (P = .10) in fetuses from Z gilts.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of zearalenone and estradiol benzoate on serum concentrations of LH, FSH and prolactin in ovariectomized gilts

Six ovariectomized gilts were given zearalenone (Z), estradiol benzoate (EB) or vehicle in a replicated 3 x 3 Latin square design. Zearalenone was added to 2.3 kg of a corn-soybean ration at a dose of 1 mg Z/kg body weight; EB was given intramuscularly at 0.1 mg EB/kg body weight. Control gilts received vehicle solvent for both Z and EB. Blood samples were collected from indwelling jugular cannulas at 6-h intervals for 48 h before Z, EB or vehicle was given. After treatment, blood samples were drawn at 6-h intervals for an additional 84 h. Serum concentrations of luteinizing hormone (LH) decreased (P<0.001) from 4.67 ng/ml to 0.29 ng/ml within 6 h of EB. From 54 to 84 h after EB, serum concentrations of LH rose to 15.60 ng/ml (P<0.001). Serum concentrations of LH were reduced (P<0.001) in a similar pattern after Z (3.70 ng/ml to 0.49 ng/ml), but a rise in serum LH was not observed 54 to 84 h after Z (1.30 ng/ml). Serum concentrations of LH remained unchanged (P=0.55) in gilts given vehicle. Serum concentrations of follicle stimulating hormone (FSH) were suppressed (P<0.03) at 6 h in EB (19.10 vs 11.35 ng/ml) and Z gilts (16.16 vs 11.41 ng/ml) but remained unchanged in vehicle gilts. Serum concentrations of FSH did not change in EB or Z gilts during the next 36 h. These data indicate that the suppressive action of Z on serum concentrations of LH and FSH was similar to that of EB, while the biphasic stimulatory effect of EB for LH was not manifested by Z.