A Review of the Use of Microparticles for Cartilage Tissue Engineering.

Tissue and organ failure has induced immense economic and healthcare concerns across the world. Tissue engineering is an interdisciplinary biomedical approach which aims to address the issues intrinsic to organ donation by providing an alternative strategy to tissue and organ transplantation. This review is specifically focused on cartilage tissue. Cartilage defects cannot readily regenerate, and thus research into tissue engineering approaches is relevant as a potential treatment option. Cells, scaffolds, and growth factors are three components that can be utilized to regenerate new tissue, and in particular recent advances in microparticle technology have excellent potential to revolutionize cartilage tissue regeneration. First, microspheres can be used for drug delivery by injecting them into the cartilage tissue or joint space to reduce pain and stimulate regeneration. They can also be used as controlled release systems within tissue engineering constructs. Additionally, microcarriers can act as a surface for stem cells or chondrocytes to adhere to and expand, generating large amounts of cells, which are necessary for clinically relevant cell therapies. Finally, a newer application of microparticles is to form them together into granular hydrogels to act as scaffolds for tissue engineering or to use in bioprinting. Tissue engineering has the potential to revolutionize the space of cartilage regeneration, but additional research is needed to allow for clinical translation. Microparticles are a key enabling technology in this regard.

Towards Mimicking the Fetal Liver Niche: The Influence of Elasticity and Oxygen Tension on Hematopoietic Stem/Progenitor Cells Cultured in 3D Fibrin Hydrogels.

Hematopoietic stem/progenitor cells (HSPCs) are responsible for the generation of blood cells throughout life. It is believed that, in addition to soluble cytokines and niche cells, biophysical cues like elasticity and oxygen tension are responsible for the orchestration of stem cell fate. Although several studies have examined the effects of bone marrow (BM) niche elasticity on HSPC behavior, no study has yet investigated the effects of the elasticity of other niche sites like the fetal liver (FL), where HSPCs expand more extensively. In this study, we evaluated the effect of matrix stiffness values similar to those of the FL on BM-derived HSPC expansion. We first characterized the elastic modulus of murine FL tissue at embryonic day E14.5. Fibrin hydrogels with similar stiffness values as the FL (soft hydrogels) were compared with stiffer fibrin hydrogels (hard hydrogels) and with suspension culture. We evaluated the expansion of total nucleated cells (TNCs), Lin-/cKit+ cells, HSPCs (Lin-/Sca+/cKit+ (LSK) cells), and hematopoietic stem cells (HSCs: LSK- Signaling Lymphocyte Activated Molecule (LSK-SLAM) cells) when cultured in 5% O2 (hypoxia) or in normoxia. After 10 days, there was a significant expansion of TNCs and LSK cells in all culture conditions at both levels of oxygen tension. LSK cells expanded more in suspension culture than in both fibrin hydrogels, whereas TNCs expanded more in suspension culture and in soft hydrogels than in hard hydrogels, particularly in normoxia. The number of LSK-SLAM cells was maintained in suspension culture and in the soft hydrogels but not in the hard hydrogels. Our results indicate that both suspension culture and fibrin hydrogels allow for the expansion of HSPCs and more differentiated progeny whereas stiff environments may compromise LSK-SLAM cell expansion. This suggests that further research using softer hydrogels with stiffness values closer to the FL niche is warranted.

Engineered Three-Dimensional Microenvironments with Starch Nanocrystals as Cell-Instructive Materials.

Naturally, cells reside in three-dimensional (3D) microenvironments composed of biopolymers that guide cellular behavior via topographical features as well as through mechanical and biochemical cues. However, most studies describing the influence of topography on cells' behavior are performed on rigid and synthetic two-dimensional substrates. To design systems that more closely resemble native microenvironments, herein we develop 3D nanocomposite hydrogels consisting of starch nanocrystals (SNCs) embedded in a gelatin matrix. The incorporation of different concentrations of SNCs (0.05, 0.2, and 0.5 wt %) results in an increase of compressive modulus when compared to hydrogels without SNCs, without affecting the swelling ratio, thus providing a tunable system. Confirming the cytocompatibility of the novel composites, the viability of encapsulated L929 fibroblasts is >90% in all hydrogels. The cellular metabolic activity and DNA content are similar for all formulations and increase over time, indicating that the fibroblasts proliferate within the hydrogels. After 4 d of culture, Live/Dead staining and F-actin/nuclei staining show that the encapsulated fibroblasts develop an elongated morphology in the hydrogels. On the other hand, encapsulated chondrogenic progenitor ATDC5 cells also maintain a viability around 90% but display a round morphology, especially in the hydrogels with SNCs, indicating a potential application of the materials for cartilage tissue engineering. We believe that topographical and mechanical cues within 3D microenvironments can be a powerful tool to instruct cells' behavior and that the developed gelatin/SNC nanocomposite warrants further study.

Prevalence of Needlestick Injuries, Attitude Changes, and Prevention Practices Over 12 Years in an Urban Academic Hospital Surgery Department.

OBJECTIVE: Needlestick injury prevalence, protection practices, and attitudes were assessed. Current medical students were compared with 2003 data to assess any changes that occurred with engineered safety feature implementation. BACKGROUND: Risk of occupational exposure to bloodborne pathogens is elevated in the operating room particularly with surgeons in training and nurses. METHODS: A cross-sectional survey was distributed to medical students (n = 358) and Department of Surgery staff (n = 247). RESULTS: The survey response rate was 24.8%. Needlestick injuries were reported by 38.7% of respondents (11% high risk), and the most common cause was "careless/accidental." Needlestick injury prevalence increased from medical students to residents and fellows (100%). Thirty-three percent of injured personnel had at least one unreported injury, and the most common reason was "inconvenient/too time consuming." Needlestick injury prevalence and double-glove use in medical students did not differ from 2003, and 25% of fellows reported always wearing double gloves. The true seroconversion rate for bloodborne pathogens was underestimated or unknown. The concern for contracting a bloodborne pathogen significantly decreased (65%) compared to 2003, and there were significantly less medical students with hepatitis B vaccinations (78.3%). Level of concern for contracting a bloodborne pathogen was predictive of needlestick injury. CONCLUSIONS: Needlestick injury and occupational exposure to bloodborne pathogens are significant hazards for surgeons and nurses. Attitudes regarding risk are changing, and the true seroconversion risk is underestimated. Educational efforts focused on needlestick injury prevalence, seroconversion rates, and double-glove perforation rates may be effective in implementing protective strategies.

In Vitro Screening of Molecularly Engineered Polyethylene Glycol Hydrogels for Cartilage Tissue Engineering using Periosteum-Derived and ATDC5 Cells.

The rapidly growing field of tissue engineering and regenerative medicine has brought about an increase in demand for biomaterials that mimic closely the form and function of biological tissues. Therefore, understanding the cellular response to the changes in material composition moves research one step closer to a successful tissue-engineered product. With this in mind, polyethylene glycol (PEG) hydrogels comprised of different concentrations of polymer (2.5%, 4%, 6.5%, or 8% (w/v)); different protease sensitive, peptide cross-linkers (VPMSMRGG or GPQGIWGQ); and the incorporation or lack of a peptide cell adhesion ligand (RGD) were screened for their ability to support in vitro chondrogenesis. Human periosteum-derived cells (hPDCs), a mesenchymal stem cell (MSC)-like primary cell source, and ATDC5 cells, a murine carcinoma-derived chondrogenic cell line, were encapsulated within the various hydrogels to assess the effects of the different formulations on cellular viability, proliferation, and chondrogenic differentiation while receiving exogenous growth factor stimulation via the medium. Through the results of this screening process, the 6.5% (w/v) PEG constructs, cross-linked with the GPQGIWGQ peptide and containing the RGD cell binding molecule, demonstrated an environment that consistently supported cellular viability and proliferation as well as chondrogenic differentiation.

Initiating human articular chondrocyte re-differentiation in a 3D system after 2D expansion.

Cartilage damage affects a large population via acute and chronic injury and disease. Since native cartilage does not self-renew, cartilage tissue engineering has gained traction as a potential treatment. However, a limiting factor is that the primary cell type in cartilage, the articular chondrocyte, tends to de-differentiate when grown on 2D surfaces for in vitro expansion. Thus, 3D systems are being developed and used to counter this loss of chondrogenic capabilities. We hypothesize that a 3D matrix that can be remodeled may be more supportive of the chondrogenic phenotype of encapsulated articular chondrocytes than a 2D surface and may allow for the re-differentiation of chondrocytes after 2D expansion. Hence, in this study, enzymatically degradable polyethylene glycol (PEG) hydrogels containing two different protease degradable peptide segments, with different degradation rates, were tested in combination with chondrogenic medium as a 3D in vitro culture system to better recapitulate the native environment of human articular chondrocytes (hACs). In addition, the effect of incorporation of the integrin binding ligand Arg-Gly-Asp (RGD) in the hydrogels was explored. Hydrogels crosslinked with a slower degrading crosslinker and not functionalized with RGD maintained hAC viability and led to increased GAG production and chondrogenic gene expression over time, suggesting that this system can initiate hAC re-differentiation after 2D expansion.

Pathogenic Rickettsia species acquire vitronectin from human serum to promote resistance to complement-mediated killing.

Bacteria of the genus Rickettsia are transmitted from arthropod vectors and primarily infect cells of the mammalian endothelial system. Throughout this infectious cycle, the bacteria are exposed to the deleterious effects of serum complement. Using Rickettsia conorii, the etiologic agent of Mediterranean spotted fever (MSF), as a model rickettsial species, we have previously demonstrated that this class of pathogen interacts with human factor H to mediate partial survival in human serum. Herein, we demonstrate that R. conorii also interacts with the terminal complement complex inhibitor vitronectin (Vn). We further demonstrate that an evolutionarily conserved rickettsial antigen, Adr1/RC1281, interacts with human vitronectin and is sufficient to mediate resistance to serum killing when expressed at the outer-membrane of serum sensitive Escherichia coli. Adr1 is an integral outer-membrane protein whose structure is predicted to contain eight membrane-embedded ß-strands and four 'loop' regions that are exposed to extracellular milieu. Site-directed mutagenesis of Adr1 revealed that at least two predicted 'loop' regions are required to mediate resistance to complement-mediatedkilling and vitronectin acquisition. These results demonstrate that rickettsial species have evolved multiple mechanisms to evade complement deposition and that evasion of killing in serum is an evolutionarily conserved virulence attribute for this genus of obligate intracellular pathogens.

Reducing Public Health Risk During Disasters: Identifying Social Vulnerabilities.

All regions of the US experience disasters which result in a number of negative public health consequences. Some populations have higher levels of social vulnerability and, thus, are more likely to experience negative impacts of disasters including emotional distress, loss of property, illness, and death. To mitigate the impact of disasters on at-risk populations, emergency managers must be aware of the social vulnerabilities within their community. This paper describes a qualitative study which aimed to understand how emergency managers identify social vulnerabilities, also referred to as at-risk populations, in their populations and barriers and facilitators to current approaches. Findings suggest that although public health tools have been developed to aid emergency managers in identifying at-risk populations, they are not being used consistently. Emergency managers requested more information on the availability of tools as well as guidance on how to increase ability to identify at-risk populations.

Skeletal tissue regeneration: where can hydrogels play a role?

The emerging field of tissue engineering reveals promising approaches for the repair and regeneration of skeletal tissues including the articular cartilage, bone, and the entire joint. Amongst the myriad of biomaterials available to support this strategy, hydrogels are highly tissue mimicking substitutes and thus of great potential for the regeneration of functional tissues. This review comprises an overview of the novel and most promising hydrogels for articular cartilage, osteochondral and bone defect repair. Chondro- and osteo-conductive and -instructive hydrogels are presented, highlighting successful combinations with inductive signals and cell sources. Moreover, advantages, drawbacks, and future perspectives of the role of hydrogels in skeletal regeneration are addressed, pointing out the current state of this rising approach.

Into the wild: uncertain frontiers and sustainable human-nature interactions.

Humans seldom consider themselves as animals, and that humans are animals is a truth frequently turned into an insulting metaphor indicating "uncivilized" behavior in many cultures. Interestingly, the "civilizing" aspects of Western Culture in the Global North are historically derived from traditions of democracy based on living in cities from which the wild has been banished. This is embedded in the English language since civilizing and civilization come from the Latin for city, civitas, the place where citizens hold voting rights. Beyond the gates of civilization is the wild. How the wild and nature have been constructed and demarcated is an enormously complex and enduring challenge in western philosophy as it relates to knowledge-making, existence, truth, and reality. Indeed, whilst people generally believe they know what nature means, they rarely realize that little in nature is wild. Furthermore, the concept of uncertainty, central to the pandemic, is compounded by climate instability and a potentially disastrous future. This is breaking down what is known, requiring porous and flexible conceptual frontiers and a transdisciplinary approach. This article traces the linguistic separation of humans from their animal origins and wilder environments for political and increasingly greedy economic purposes. It explores the acknowledged complexity of healthy human-nature interactions, juxtaposing information mainly from the humanities and social sciences. Demonstrating how unhealthy the current paradigm has proven to be for humans and the natural world, it brings together conflicting information to disrupt traditional certainties using an innovative bricolage methodology. It weaves and combines different ways of knowing as it considers forms of knowledge-making, rewilding, foraging, the place of magical thinking, and vital force. It concludes that a new paradigm is needed to enable a way of working toward any vision of healthy human-nature interaction.

A literature review of the social and psychological needs of ovarian cancer survivors.

OBJECTIVE: To identify and comprehensively present the psychosocial needs of ovarian cancer (OvCa) survivors, including young survivors <45 years of age. METHODS: A literature review was conducted using keywords specific to psychosocial health and OvCa survivorship to identify peer-reviewed, original research articles published in English between January 2000 and December 2010; 28 articles were identified as relevant. Articles were abstracted and results categorized according to six psychosocial domains: quality of life (QoL), social support and relationships, self-image and sexual functioning, psychological distress and functioning, fear of death/recurrence, and personal growth and coping. Findings unique to young survivors are presented when applicable. Psychosocial measurement tools used in relevant studies are also presented. RESULTS: Physical complications and side effects have significant impact on OvCa survivors' psychosocial health. Access to social support services and relational support is critical, as feelings of isolation are common. Survivors report low levels of sexual activity and satisfaction, potentially causing strain on personal relationships, and survivors experience high levels of distress, depression, and anxiety. However, QoL can improve after diagnosis for some OvCa survivors, many of whom report spiritual growth and strengthened personal relationships. Younger survivors are likely to have greater distress and lower QoL compared with older survivors. CONCLUSIONS: OvCa is the deadliest of all gynecologic cancers, greatly impacting the psychosocial health of survivors. Increased awareness of psychosocial health among OvCa survivors themselves, their social support system, and their health care providers is necessary to adequately address their unique needs.

Archaeal and eukaryotic homologs of Hfq: A structural and evolutionary perspective on Sm function.

Hfq and other Sm proteins are central in RNA metabolism, forming an evolutionarily conserved family that plays key roles in RNA processing in organisms ranging from archaea to bacteria to human. Sm-based cellular pathways vary in scope from eukaryotic mRNA splicing to bacterial quorum sensing, with at least one step in each of these pathways being mediated by an RNA-associated molecular assembly built upon Sm proteins. Though the first structures of Sm assemblies were from archaeal systems, the functions of Sm-like archaeal proteins (SmAPs) remain murky. Our ignorance about SmAP biology, particularly vis-à-vis the eukaryotic and bacterial Sm homologs, can be partly reduced by leveraging the homology between these lineages to make phylogenetic inferences about Sm functions in archaea. Nevertheless, whether SmAPs are more eukaryotic (RNP scaffold) or bacterial (RNA chaperone) in character remains unclear. Thus, the archaeal domain of life is a missing link, and an opportunity, in Sm-based RNA biology.

Issues of ovarian cancer survivors in the USA: a literature review.

PURPOSE: As the number of ovarian cancer survivors increases, so does the need for appropriate intervention and care. A literature review was conducted to assess the issues affecting ovarian cancer survivors in the USA, including the needs of younger survivors. METHODS: Articles on six topics (finances/employment, reproductive and sexual health, treatment effects, information needs, genomics, and end-of-life/palliative care) among ovarian cancer survivors were identified through comprehensive database searches. Abstracts for all citations were reviewed to determine relevancy. Data from relevant articles, defined as including a sample size of ≥ 20, published in English, involving human subjects in the USA, and published between 2000 and 2010, were abstracted. RESULTS: Thirty-four articles were relevant. Common, but often unaddressed, treatment side effects included infertility and issues with sexual health. Survivors reported not receiving adequate information about their disease. Hereditary cancer can lead to concern for family members. End-of-life/palliative care was often not addressed by physicians. Most of the studies used a cross-sectional design and lacked control groups. Participants were primarily recruited from academic medical centers or clinical trials and tended to be White. Few studies specifically addressed young survivors; however, reproductive health issues are common. CONCLUSIONS: Ovarian cancer has wide-ranging impacts. This review emphasizes the need for more research among ovarian cancer survivors, particularly related to finances, reproductive and sexual health, information, genomics, and end-of-life care. Issues specific to young survivors also deserve more attention. Direction for future research and clinical implications are discussed.

The rickettsial OmpB ß-peptide of Rickettsia conorii is sufficient to facilitate factor H-mediated serum resistance.

Pathogenic species of the spotted fever group Rickettsia are subjected to repeated exposures to the host complement system through cyclic infections of mammalian and tick hosts. The serum complement machinery is a formidable obstacle for bacteria to overcome if they endeavor to endure this endozoonotic cycle. We have previously demonstrated that that the etiologic agent of Mediterranean spotted fever, Rickettsia conorii, is susceptible to complement-mediated killing only in the presence of specific monoclonal antibodies. We have also shown that in the absence of particular neutralizing antibody, R. conorii is resistant to the effects of serum complement. We therefore hypothesized that the interactions between fluid-phase complement regulators and conserved rickettsial outer membrane-associated proteins are critical to mediate serum resistance. We demonstrate here that R. conorii specifically interacts with the soluble host complement inhibitor, factor H. Depletion of factor H from normal human serum renders R. conorii more susceptible to C3 and membrane attack complex deposition and to complement-mediated killing. We identified the autotransporter protein rickettsial OmpB (rOmpB) as a factor H ligand and further demonstrate that the rOmpB ß-peptide is sufficient to mediate resistance to the bactericidal properties of human serum. Taken together, these data reveal an additional function for the highly conserved rickettsial surface cell antigen, rOmpB, and suggest that the ability to evade complement-mediated clearance from the hematogenous circulation is a novel virulence attribute for this class of pathogens.

A Rare Case of Candida parapsilosis Lumbar Discitis With Osteomyelitis.

Fungal osteomyelitis is rare and usually seen in immunocompromised patients. We report a case of Candida parapsilosis osteomyelitis in an immunocompetent patient with no prior surgical history. He went for spinal laminectomy with debridement and drainage. Intraoperative culture grew C. parapsilosis, and the patient was treated with fluconazole.

The effects of nurse to patient ratios.

This article examines the literature on nurse to patient ratios to establish the impact on both patients and staff of understaffing on hospital wards. It discusses theories on ideal staff to patient ratios and the resource implications of these, and recommends a number of dynamic and innovative ways to allocate staff.

High-Resolution Bioprinting of Recombinant Human Collagen Type III.

The development of commercial collagen inks for extrusion-based bioprinting has increased the amount of research on pure collagen bioprinting, i.e., collagen inks not mixed with gelatin, alginate, or other more common biomaterial inks. New printing techniques have also improved the resolution achievable with pure collagen bioprinting. However, the resultant collagen constructs still appear too weak to replicate dense collagenous tissues, such as the cornea. This work aims to demonstrate the first reported case of bioprinted recombinant collagen films with suitable optical and mechanical properties for corneal tissue engineering. The printing technology used, aerosol jet® printing (AJP), is a high-resolution printing method normally used to deposit conductive inks for electronic printing. In this work, AJP was employed to deposit recombinant human collagen type III (RHCIII) in overlapping continuous lines of 60 µm to form thin layers. Layers were repeated up to 764 times to result in a construct that was considered a few hundred microns thick when swollen. Samples were subsequently neutralised and crosslinked using EDC:NHS crosslinking. Nanoindentation and absorbance measurements were conducted, and the results show that the AJP-deposited RHCIII samples possess suitable mechanical and optical properties for corneal tissue engineering: an average effective elastic modulus of 506 ± 173 kPa and transparency ≥87% at all visible wavelengths. Circular dichroism showed that there was some loss of helicity of the collagen due to aerosolisation. SDS-PAGE and pepsin digestion were used to show that while some collagen is degraded due to aerosolisation, it remains an inaccessible substrate for pepsin cleavage.

Advanced Methods for the Characterization of Supramolecular Hydrogels.

With the increased research on supramolecular hydrogels, many spectroscopic, diffraction, microscopic, and rheological techniques have been employed to better understand and characterize the material properties of these hydrogels. Specifically, spectroscopic methods are used to characterize the structure of supramolecular hydrogels on the atomic and molecular scales. Diffraction techniques rely on measurements of crystallinity and help in analyzing the structure of supramolecular hydrogels, whereas microscopy allows researchers to inspect these hydrogels at high resolution and acquire a deeper understanding of the morphology and structure of the materials. Furthermore, mechanical characterization is also important for the application of supramolecular hydrogels in different fields. This can be achieved through atomic force microscopy measurements where a probe interacts with the surface of the material. Additionally, rheological characterization can investigate the stiffness as well as the shear-thinning and self-healing properties of the hydrogels. Further, mechanical and surface characterization can be performed by micro-rheology, dynamic light scattering, and tribology methods, among others. In this review, we highlight state-of-the-art techniques for these different characterization methods, focusing on examples where they have been applied to supramolecular hydrogels, and we also provide future directions for research on the various strategies used to analyze this promising type of material.

Medical Malpractice in Nerve Injury of the Upper Extremity.

Background: Medical malpractice accounts for more than $55 billion of annual health care costs. Updated malpractice risk to surgeons and physicians related to upper extremity peripheral nerve injury has not been published. Methods: A comprehensive database analysis of upper extremity nerve injury claims between 1995 and 2014 in the United States was conducted using the Medical Professional Liability Association Data Sharing Project, representing 24 major insurance companies. Results: Nerve injury in the upper extremity accounted for 614 (0.3%) malpractice claims (total of 188 323). Common presenting diagnoses included carpal tunnel syndrome (41%), upper extremity fractures (19%), and traumatic nerve injuries to the shoulder or upper limb (8%). Improper performance (49% of total claims) and claims without evidence of medical error (19%) were the most common malpractice suits. Orthopedic surgeons were the most frequently targeted specialists (42%). In all, 65% of nerve injury claims originated from operative procedures in a hospital, 59% of claims were dismissed or withdrawn prior to trial, and 30% resulted in settlements. Thirty-three percent of claims resulted in an indemnity payment to an injured party, with an average payout of $203 592 per successful suit. Only 8% of claims resulted in a completed trial and verdict, and verdicts were overwhelmingly in favor of the defendant (83%). Conclusions: Most malpractice claims from peripheral nerve injuries in the United States arise from the management of common diagnoses, occur in the operating room, and allege improper performance. Strategies to reduce malpractice risk should emphasize the management of common conditions and patient-physician communication.

Effects of physical or fenceline boar exposure and exogenous gonadotropins on puberty induction and subsequent fertility in gilts.

The present study was part of a larger experiment that evaluated litter of origin effects on gilt production. The objectives of this study were to determine the effect of physical or fenceline boar exposure and exogenous gonadotropins on puberty induction and subsequent fertility in a commercial farm environment. The experiment was performed in three replicates. Prepubertal gilts were assigned by pen (13/pen) to receive 15 min of daily Fenceline (FBE, n = 153) or Physical (PBE, n = 154) Boar Exposure (BE) for 3 weeks starting at 184 d of age in a purpose-designed Boar Exposure Area (BEAR). At the start of week 3, prepubertal gilts were randomly assigned to receive PG600 or none (Control). From weeks 4 to 6, estrus was checked using only FBE. During weeks 1 to 3, measures of reproductive status were obtained weekly or until expression of estrus. Upon detection of first estrus, gilts were relocated into stalls and inseminated at second estrus. PBE reduced age (P = 0.001) and days to puberty (P = 0.002), increased the proportion of gilts in estrus (P = 0.04) in week 1 (38.3 vs. 27.5%), and tended (P = 0.08) to improve estrus in week 2 (37.6 vs. 26.1%) compared to FBE, respectively. In week 3, more prepubertal gilts receiving PBE-PG600 exhibited estrus (P = 0.04; 81.8%) compared to PBE-Control (40.3%), FBE-PG600 (56.4%), and FBE-Control (47.8%). Overall, expression of estrus through week 6 tended (P = 0.08) to be greater for PBE than FBE (91.5 vs. 85.0%). PBE increased (P ≤ 0.05) or tended to increase (P > 0.05 and ≤0.10) service and farrowing rates in parities 1 through 4, but within parity, there were no effects (P > 0.10) on pig production or wean to service interval. Analyses also indicated that weeks from start of boar exposure to puberty, litter of origin traits, and follicle measures at puberty were related to the subsequent fertility. The results of this study confirm the advantages of using increased intensity of boar exposure, combined with PG600 treatment, for effective induction of pubertal estrus in a commercial setting.