'Nobody taught her how to be a mother': The lived experience of mothering without a mother.

Maternal grandmothers play a vital role in the transition to motherhood for their own daughters. The current study adds to this literature by investigating the lived experience of motherhood for women who lacked a meaningful relationship with their mothers. Ten mothers of children under 2 years of age participated in a semi-structured interview to explore their lived experiences of being a mother. Women were recruited from two parent-infant services in Northern Ireland. The interviews were analyzed using Interpretive Phenomenological Analysis (IPA). Three superordinate themes were identified: 'The Birth of a Mother', 'Mourning and Loss' and 'Ghosts in the Nursery'. The first theme captured the significant change of identity women experienced during their transition to motherhood. This identity change shed new light on their own experience of being mothered. The second theme captured the mourning and loss these women felt due to their relationship with their mother. Their lack of meaningful maternal relationships have left a hole impossible to fill. The final theme spoke to the intergenerational element of these mother's experience and their desire to break a cycle of maternal deprivation. The rich content from the interviews highlights the need for services to be aware of this struggle of motherhood.

Las abuelas maternas juegan un papel vital en la transición a la maternidad para sus propias hijas. El presente estudio contribuye a este campo de conocimientos escritos por medio de investigar la experiencia de maternidad vividas por mujeres a quienes les hace falta una significativa relación con sus madres. Diez madres de niños menores de dos años de edad participaron en una entrevista semiestructurada para explorar sus vividas experiencias de ser madre. A las mujeres se les reclutó de dos servicios progenitor-infante en Irlanda del Norte. Se analizaron las entrevistas usando el Análisis Fenomenológico Interpretativo (IPA). Se identificaron tres temas de nivel superior: 'El Nacimiento de una Madre,' 'Lamento y Pérdida' y 'Fantasmas en el Cuarto de la Niña.' El primer tema captó el significativo cambio de identidad que las mujeres experimentan durante su transición a la maternidad. El cambio de identidad arrojó una nueva luz en sus propias experiencias de ser criadas por una madre. El segundo tema captó la lamentación y la pérdida que estas mujeres sentían debido a su relación con sus madres. La falta de significativas relaciones maternas ha dejado un vacío imposible de llenar. El tema final tuvo que ver que el elemento intergeneracional de la experiencia de estas madres y su deseo de romper un ciclo de privación materna. El rico contenido de las entrevistas enfatiza la necesidad de servicios para estar conscientes de esta lucha sobre la maternidad.

Les grands-mères maternelles jouent un rôle vital dans la transition à la maternité de leurs propres filles. Cette étude s'ajoute aux recherches précédentes en enquêtant sur l'expérience vécue de la maternité pour les femmes n'ayant pas eu une relation importante avec leurs mères. Dix mères d'enfant de moins de deux ans ont participé à un entretien semi structuré afin d'explorer leurs expériences vécues du fait d'être maman. Ces femmes ont été recrutées dans deux services parent-bébé en Irlande du Nord. Ces entretiens ont été analysés en utilisant l'Analyse Interprétive Phénoménologique (en anglais Interpretive Phenomenological Analysis, soit IPA). Trois thèmes supérieurs ont été identifiés: 'La Naissance d'une Mère', "Deuil et Perte' et 'Fantômes dans la Chambre d'enfant'. Le premier thème a capture le changement d'identité important que les femmes ont vécu durant leurs transitions à la maternité. Ce changement d'identité a apporté un éclairage nouveau sur leur propre expérience d'avoir été maternées. Le second thème a capturé le deuil et la perte que ces femmes ont ressentis du fait de leur lien à leur mère. Leur manque de relations maternelles importantes a laissé un trou impossible à remplir. Le dernier thème fait référence à l'élément intergénérationnel de l'expérience de ces mères et leur désir de casser un cycle de privation maternelle. Ce contenu riche émanant des entretiens met en lumière la prise de connaissance nécessaire de ces difficultés de la maternité dont doivent faire preuve les services.

Modeling the distribution of the endangered Jemez Mountains salamander (Plethodon neomexicanus) in relation to geology, topography, and climate.

The Jemez Mountains salamander (Plethodon neomexicanus; hereafter JMS) is an endangered salamander restricted to the Jemez Mountains in north-central New Mexico, United States. This strictly terrestrial and lungless species requires moist surface conditions for activities such as mating and foraging. Threats to its current habitat include fire suppression and ensuing severe fires, changes in forest composition, habitat fragmentation, and climate change. Forest composition changes resulting from reduced fire frequency and increased tree density suggest that its current aboveground habitat does not mirror its historically successful habitat regime. However, because of its limited habitat area and underground behavior, we hypothesized that geology and topography might play a significant role in the current distribution of the salamander. We modeled the distribution of the JMS using a machine learning algorithm to assess how geology, topography, and climate variables influence its distribution. The best habitat suitability model indicates that geology type and maximum winter temperature (November to March) were most important in predicting the distribution of the salamander (23.5% and 50.3% permutation importance, respectively). Minimum winter temperature was also an important variable (21.4%), suggesting this also plays a role in salamander habitat. Our habitat suitability map reveals low uncertainty in model predictions, and we found slight discrepancies between the designated critical habitat and the most suitable areas for the JMS. Because geological features are important to its distribution, we recommend that geological and topographical data are considered, both during survey design and in the description of localities of JMS records once detected.

Does Age, Residency, or Feeding Guild Coupled with a Drought Index Predict Avian Health during Fall Migration?

Birds are good indicators of environmental change and are often studied for responses to climate. Many studies focus on breeding birds, while fewer look at the migration period, which is a critical time for many birds. Birds are more susceptible to unusual climatic events during their migration due to the metabolic stress of long-distance movements. In the fall of 2020, an unusual cold weather event coupled with drought and wildfire smoke led to a large avian mortality event in New Mexico. Later analysis pointed to the mortality being largely due to starvation. This was the impetus for our research. We used 11 years of fall bird banding data from two locations, along with local drought indices, to determine what predicts avian health during the migration period. We used fat score data from over 15,000 individual birds to assess whether drought indices, age, diet, or residency influenced avian health using multiple logistic regression. We found that the probability of positive fat scores decreased as drought severity increased for younger, insectivorous, migratory birds. Insectivores had a higher probability of receiving a fat score greater than zero relative to local drought conditions, which is important, since many North American insectivores are in steep decline. Migratory birds showed a greater response than year-round residents, and older birds showed a lower but significant response compared to hatch-year birds. Our results suggest that migratory insectivores in the southwestern United States may be less resilient to drought-related climate change.

Investigating effects of soil chemicals on density of small mammal bioindicators using spatial capture-recapture models.

Monitoring the ecological impacts of environmental pollution and the effectiveness of remediation efforts requires identifying relationships between contaminants and the disruption of biological processes in populations, communities, or ecosystems. Wildlife are useful bioindicators, but traditional comparative experimental approaches rely on a staunch and typically unverifiable assumption that, in the absence of contaminants, reference and contaminated sites would support the same densities of bioindicators, thereby inferring direct causation from indirect data. We demonstrate the utility of spatial capture-recapture (SCR) models for overcoming these issues, testing if community density of common small mammal bioindicators was directly influenced by soil chemical concentrations. By modeling density as an inhomogeneous Poisson point process, we found evidence for an inverse spatial relationship between Peromyscus density and soil mercury concentrations, but not other chemicals, such as polychlorinated biphenyls, at a site formerly occupied by a nuclear reactor. Although the coefficient point estimate supported Peromyscus density being lower where mercury concentrations were higher (ß = -0.44), the 95% confidence interval overlapped zero, suggesting no effect was also compatible with our data. Estimated density from the most parsimonious model (2.88 mice/ha; 95% CI = 1.63-5.08), which did not support a density-chemical relationship, was within the range of reported densities for Peromyscus that did not inhabit contaminated sites elsewhere. Environmental pollution remains a global threat to biodiversity and ecosystem and human health, and our study provides an illustrative example of the utility of SCR models for investigating the effects that chemicals may have on wildlife bioindicator populations and communities.

Avian demographic responses to drought and fire: a community-level perspective.

Drought stress is an important consideration for wildlife in arid and semiarid regions under climate change. Drought can impact plant and animal populations directly, through effects on their physiology, as well as indirectly through effects on vegetation productivity and resource availability, and by creating conditions conducive to secondary disturbance, such as wildfire. We implemented a novel approach to understanding community-level demographic responses of birds and their habitats to these stressors in the context of climate change at 14 study sites in the Four Corners region of the southwestern United States. A large wildfire affecting three of the sites provided a natural experiment for also examining fire effects on vegetation and the bird community. We assessed (1) trends in drought and end-of-century (2071-2100) predicted average drought conditions under mid-range and high greenhouse gas concentration trajectory scenarios; (2) effects of drought and fire on habitat (vegetation greenness); and (3) effects of drought and fire on community-level avian productivity and adult apparent survival rates. Drought has increased and is expected to increase further at our study sites under climate change. Under spring drought conditions, vegetation greenness and avian productivity declined, while summer drought appeared to negatively affect adult apparent survival rates. Response to fire was mixed; in the year of the fire, avian productivity declined, but was higher than normal for several years post-fire. Our results highlight important links between environmental stressors and avian vital rates that will likely affect population trajectories in this region under climate change. We suggest that the use and continued development of community-level demographic models will provide useful tool for leveraging sparse species-level data to provide multi-species inferences and inform conservation.

The long-term effect of maternal dietary protein restriction on 5-HT1A receptor function and behavioral responses to stress in adulthood.

Maternal nutrition impacts fetal development, and may play a role in determining resilience to stress and vulnerability to stress-precipitated psychiatric disorders, such as anxiety and depression. In this study, we examined the effect of a reduction in maternal dietary protein during pregnancy on the brain neurochemistry and behavior of offspring. We focused specifically on the serotonin system, the 5-HT1A receptor and the responsivity of offspring as adults to stress. Dams were fed either a low protein diet (10% protein by weight) or isocaloric control diet (20% protein by weight). The low protein diet did not alter maternal food intake and body weight, or litter size and the average birth weight of male or female littermates. 5-HT1A receptor function, as measured by quantitative autoradiography of 8-OH-DPAT (1 µM)-stimulated [35S]GTPγS binding, was markedly reduced in hippocampus of weanling female, but not male offspring (postnatal day, PND 21) of dams fed the low protein diet. The number of serotonergic cell bodies in the rostral raphe, and 5-HT metabolism in the limbic system of weanling offspring was not altered by maternal low protein diet. The deficit in hippocampal 5-HT1A receptor function observed in weanling female offspring persisted into adulthood (PND 112), and was accompanied by an increased sensitivity to stress, specifically increased immobility during a 15-minute forced swim challenge and increased anorexia following 30-minute restraint (PND 97-100). The present work begins to uncover important future directions for understanding the early developmental origins of resilience to stress, and factors that may put individuals at greater risk for stress-related psychiatric disorders.

Inhibition of the Serotonin Transporter Is Altered by Metabolites of Selective Serotonin and Norepinephrine Reuptake Inhibitors and Represents a Caution to Acute or Chronic Treatment Paradigms.

Previous studies of transgenic mice carrying a single isoleucine to methionine substitution (I172M) in the serotonin transporter (SERT) demonstrated a loss of sensitivity to multiple antidepressants (ADs) at SERT. However, the ability of AD metabolites to antagonize SERT was not assessed. Here, we evaluated the selectivity and potency of these metabolites for inhibition of SERT in mouse brain-derived synaptosomes and blood platelets from wild-type (I172 mSERT) and the antidepressant-insensitive mouse M172 mSERT. The metabolites norfluoxetine and desmethylsertraline lost the selectivity demonstrated by the parent compounds for inhibition of wild-type mSERT over M172 mSERT, whereas desvenlafaxine and desmethylcitalopram retained selectivity. Furthermore, we show that the metabolite desmethylcitalopram accumulates in the brain and that the metabolites desmethylcitalopram, norfluoxetine, and desvenlafaxine inhibit serotonin uptake in wild-type mSERT at potencies similar to those of their parent compounds, suggesting that metabolites may play a role in effects observed following AD administration in wild-type and M172 mice.

Perceptions of human cadaver dissection by medical students: a highly valued experience.

Cadaver dissection remains a cornerstone in the study of anatomical sciences by medical students. However, this activity can cause emotions that may affect learning outcomes. This study, which involved medical students of various cultural backgrounds, assessed their responses to dissection. Medicine I year students (n = 100) at Oakland University William Beaumont School of Medicine were invited to complete a questionnaire after the first week of dissection, and again at the end of the course. The questionnaire asked for demographics, and assessed the students' appraisal of their dissection experience, cultural influences, coping activities and learning outcomes. After the first week of dissection, most of the students found the experience challenging, stimulating, exciting and informative, rather than nauseating or unbearable. Still, some students found the experience anxiety-provoking, especially when they thought about human mortality. Cultural background influenced the students' emotional development as they worked through the course. Most of the participants agreed that dissection promotes teamwork, familiarity with the human body, and integration of the theoretical knowledge with practical application. At the end of the course, dissection was significantly less anxiety-provoking, and, interestingly, the study found that culture and religious beliefs became more important to the students. Most students agreed that dissection is important, relevant, and necessary, and has the potential to improve learning outcomes that are essential to the development of physicians. The study suggests that an introductory course in social, behavioral and ethical considerations be presented at the beginning of the medical curriculum.

Impaired development of fetal serotonergic neurons in intrauterine growth restricted baboons.

We studied development of the fetal serotonergic central nervous system in a baboon, non-human primate model of intrauterine growth restriction (IUGR). Fetal (90% of full-term) IUGR brains were comparable in size to controls, but have reduced expression of serotonergic proteins and mRNAs, as well as having fewer serotonergic neurons.

Evaluation of bison (Bison bison) semen from Yellowstone National Park, Montana, USA, bulls for Brucella abortus shedding.

To determine if bison (Bison bison) bulls from Yellowstone National Park (YNP), Montana, USA, shed an infective dose of Brucella abortus in semen, 50 YNP bulls were captured on public lands in Montana during the winter and early spring (April-May) of 2010 and 2011. The bulls were immobilized, and blood and semen samples were collected for serology and Brucella culture. Thirty-five bulls (70%) were antibody-positive, and B. abortus was cultured from semen in three (9%) of the 35 antibody-positive or suspect bulls, though not at concentrations considered an infective dose. Eight bulls (six antibody-positive, two negative) had palpable lesions of the testes, epididymides, or seminal vesicles consistent with B. abortus infection. Breeding soundness exams and semen analysis suggested that antibody-positive bulls were more likely to have nonviable ejaculate (8/35; 23%) than bulls without detectable antibody (2/15; 13%).

Autism gene variant causes hyperserotonemia, serotonin receptor hypersensitivity, social impairment and repetitive behavior.

Fifty years ago, increased whole-blood serotonin levels, or hyperserotonemia, first linked disrupted 5-HT homeostasis to Autism Spectrum Disorders (ASDs). The 5-HT transporter (SERT) gene (SLC6A4) has been associated with whole blood 5-HT levels and ASD susceptibility. Previously, we identified multiple gain-of-function SERT coding variants in children with ASD. Here we establish that transgenic mice expressing the most common of these variants, SERT Ala56, exhibit elevated, p38 MAPK-dependent transporter phosphorylation, enhanced 5-HT clearance rates and hyperserotonemia. These effects are accompanied by altered basal firing of raphe 5-HT neurons, as well as 5HT(1A) and 5HT(2A) receptor hypersensitivity. Strikingly, SERT Ala56 mice display alterations in social function, communication, and repetitive behavior. Our efforts provide strong support for the hypothesis that altered 5-HT homeostasis can impact risk for ASD traits and provide a model with construct and face validity that can support further analysis of ASD mechanisms and potentially novel treatments.

Transgenic elimination of high-affinity antidepressant and cocaine sensitivity in the presynaptic serotonin transporter.

Serotonin [i.e., 5-hydroxytryptamine (5-HT)]-targeted antidepressants are in wide use for the treatment of mood disorders, although many patients do not show a response or experience unpleasant side effects. Psychostimulants, such as cocaine and 3,4-methylenedioxymethamphetamine (i.e., "ecstasy"), also impact 5-HT signaling. To help dissect the contribution of 5-HT signaling to the actions of these and other agents, we developed transgenic mice in which high-affinity recognition of multiple antidepressants and cocaine is eliminated. Our animals possess a modified copy of the 5-HT transporter (i.e., SERT, slc6a4) that bears a single amino acid substitution, I172M, proximal to the 5-HT binding site. Although the M172 substitution does not impact the recognition of 5-HT, this mutation disrupts high-affinity binding of many competitive antagonists in transfected cells. Here, we demonstrate that, in M172 knock-in mice, basal SERT protein levels, 5-HT transport rates, and 5-HT levels are normal. However, SERT M172 mice display a substantial loss of sensitivity to the selective 5-HT reuptake inhibitors fluoxetine and citalopram, as well as to cocaine. Through a series of biochemical, electrophysiological, and behavioral assays, we demonstrate the unique properties of this model and establish directly that SERT is the sole protein responsible for selective 5-HT reuptake inhibitor-mediated alterations in 5-HT clearance, in 5-HT1A autoreceptor modulation of raphe neuron firing, and in behaviors used to predict the utility of antidepressants.

Modeling rare gene variation to gain insight into the oldest biomarker in autism: construction of the serotonin transporter Gly56Ala knock-in mouse.

Alterations in peripheral and central indices of serotonin (5-hydroxytryptamine, 5-HT) production, storage and signaling have long been associated with autism. The 5-HT transporter gene (HTT, SERT, SLC6A4) has received considerable attention as a potential risk locus for autism-spectrum disorders, as well as disorders with overlapping symptoms, including obsessive-compulsive disorder (OCD). Here, we review our efforts to characterize rare, nonsynonymous polymorphisms in SERT derived from multiplex pedigrees carrying diagnoses of autism and OCD and present the initial stages of our effort to model one of these variants, Gly56Ala, in vivo. We generated a targeting vector to produce the Gly56Ala substitution in the Slc6a4 locus by homologous recombination. Following removal of a neomycin resistance selection cassette, animals exhibiting germline transmission of the Ala56 variant were bred to establish a breeding colony on a 129S6 background, suitable for initial evaluation of biochemical, physiological and behavioral alterations relative to SERT Gly56 (wild-type) animals. SERT Ala56 mice were achieved and exhibit a normal pattern of transmission. The initial growth and gross morphology of these animals is comparable to wildtype littermate controls. The SERT Ala56 variant can be propagated in 129S6 mice without apparent disruption of fertility and growth. We discuss both the opportunities and challenges that await the physiological/behavioral analysis of Gly56Ala transgenic mice, with particular reference to modeling autism-associated traits.

Functional coding variation in recombinant inbred mouse lines reveals multiple serotonin transporter-associated phenotypes.

The human serotonin (5-hydroxytryptamine, 5-HT) transporter (hSERT, SLC6A4) figures prominently in the etiology and treatment of many prevalent neurobehavioral disorders including anxiety, alcoholism, depression, autism, and obsessive-compulsive disorder (OCD). Here, we use naturally occurring polymorphisms in recombinant inbred (RI) lines to identify multiple phenotypes associated with altered SERT function. The widely used mouse strain C57BL/6J, harbors a SERT haplotype defined by 2 nonsynonymous coding variants [Gly-39 and Lys-152 (GK)]. At these positions, many other mouse lines, including DBA/2J, encode, respectively, Glu-39 and Arg-152 (ER haplotype), amino acids found also in hSERT. Ex vivo synaptosomal 5-HT transport studies revealed reduced uptake associated with the GK variant, a finding confirmed by in vitro heterologous expression studies. Experimental and in silico approaches using RI lines (C57BL/6J x DBA/2J = BXD) identify multiple anatomical, biochemical, and behavioral phenotypes specifically impacted by GK/ER variation. Among our findings are several traits associated with alcohol consumption and multiple traits associated with dopamine signaling. Further bioinformatic analysis of BXD phenotypes, combined with biochemical evaluation of SERT knockout mice, nominates SERT-dependent 5-HT signaling as a major determinant of midbrain iron homeostasis that, in turn, dictates iron-regulated DA phenotypes. Our studies provide an example of the power of coordinated in vitro, in vivo, and in silico approaches using mouse RI lines to elucidate and quantify the system-level impact of gene variation.

Capacity of hospitals to partner with academia to meet experiential education requirements for pharmacy students.

PURPOSE: Current hospital and health-system participation in and the future capacity for experiential education for pharmacy students was investigated. METHODS: An online survey of ASHP members identified as U.S. pharmacy directors was conducted to assess their current and future involvement in partnering with colleges and schools to meet the experiential education requirements for doctor of pharmacy students and the current status of the student learning experiences. Questionnaire items examined the factors on which expanded involvement in experiential education would depend, the nature of support provided by colleges and schools, the types of experiences available for students, respondents' perceptions of factors influencing the quality of experiential education, the value of experiential education to the sites, respondents' challenges and concerns about experiential education, and respondents' current capacity and projections for introductory and advanced experiences through 2012. RESULTS: Data from 549 respondents were analyzed. Most respondents indicated that they had conducted advanced experiences for their 2007 graduates and anticipated that they would continue to do so. Among the top challenges identified regarding advanced experiences were concerns about time to serve and be trained as preceptors and a lack of standardization and coordination among colleges and schools. Hospitals forecasting their future capacity to accommodate students indicated that their projections were highly dependent on the number of pharmacists at their hospitals. Many respondents noted that their capacity projections were tied to their ability to expand clinical services at their hospitals. CONCLUSION: A survey of pharmacy directors suggested an ability of U.S. hospitals to conduct advanced experiential education opportunities for pharmacy students through 2012 and to expand introductory experiences.

Protective roles of alpha-calcitonin and beta-calcitonin gene-related peptide in spontaneous and experimentally induced colitis.

Calcitonin gene-related peptide (CGRP) is thought to be involved in the regulation of gastric and mesenteric blood flow, in the control of gastric acid secretion and in the modulation of intestinal motility, yet the precise physiological roles of CGRP remain to be elucidated. To further examine the role(s) of CGRP in gastrointestinal function, we examined mutant mice lacking alphaCGRP or betaCGRP expression. Mutant mice did not demonstrate any overt phenotypic changes, yet exhibited a spontaneous, adult-onset colitis and increased colonic damage using a dextran sulfate sodium model of experimental colitis. Surprisingly, mice lacking betaCGRP show no obvious alterations in CGRP immunoreactivity in the gut, accompanied by an increase in alphaCGRP messenger RNA expression, suggesting an adaptive mechanism to compensate for the lack of betaCGRP. These data demonstrate that both alphaCGRP and betaCGRP play a protective role in the generation of spontaneous colitis, supporting a role for both extrinsic and intrinsic CGRP-containing neurons.

Effect of ACL deficiency on MCL strains and joint kinematics.

The knee joint is partially stabilized by the interaction of multiple ligament structures. This study tested the interdependent functions of the anterior cruciate ligament (ACL) and the medial collateral ligament (MCL) by evaluating the effects of ACL deficiency on local MCL strain while simultaneously measuring joint kinematics under specific loading scenarios. A structural testing machine applied anterior translation and valgus rotation (limits 100 N and 10 N m, respectively) to the tibia of ten human cadaveric knees with the ACL intact or severed. A three-dimensional motion analysis system measured joint kinematics and MCL tissue strain in 18 regions of the superficial MCL. ACL deficiency significantly increased MCL strains by 1.8% (p<0.05) during anterior translation, bringing ligament fibers to strain levels characteristic of microtrauma. In contrast, ACL transection had no effect on MCL strains during valgus rotation (increase of only 0.1%). Therefore, isolated valgus rotation in the ACL-deficient knee was nondetrimental to the MCL. The ACL was also found to promote internal tibial rotation during anterior translation, which in turn decreased strains near the femoral insertion of the MCL. These data advance the basic structure-function understanding of the MCL, and may benefit the treatment of ACL injuries by improving the knowledge of ACL function and clarifying motions that are potentially harmful to secondary stabilizers.

Effect of dermatan sulfate glycosaminoglycans on the quasi-static material properties of the human medial collateral ligament.

The glycosaminoglycan of decorin, dermatan sulfate (DS), has been suggested to contribute to the mechanical properties of soft connective tissues such as ligaments and tendons. This study investigated the mechanical function of DS in human medial collateral ligaments (MCL) using nondestructive shear and tensile material tests performed before and after targeted removal of DS with chondroitinase B (ChB). The quasi-static elastic material properties of human MCL were unchanged after DS removal. At peak deformation, tensile and shear stresses in ChB treated tissue were within 0.5% (p>0.70) and 2.0% (p>0.30) of pre-treatment values, respectively. From pre- to post-ChB treatment under tensile loading, the tensile tangent modulus went from 242+/-64 to 233+/-57 MPa (p=0.44), and tissue strain at peak deformation went from 4.3+/-0.3% to 4.4+/-0.3% (p=0.54). Tissue hysteresis was unaffected by DS removal for both tensile and shear loading. Biochemical analysis confirmed that 90% of DS was removed by ChB treatment when compared to control samples, and transmission electron microscopy (TEM) imaging further verified the degradation of DS by showing an 88% reduction (p<.001) of sulfated glycosaminoglycans in ChB treated tissue. These results demonstrate that DS in mature knee MCL tissue does not resist tensile or shear deformation under quasi-static loading conditions, challenging the theory that decorin proteoglycans contribute to the elastic material behavior of ligament.