Local gun violence, mental health, and sleep: A neighborhood analysis in one hundred US Cities.

RATIONALE: Community gun violence significantly shapes public health and collective well-being. Understanding how gun violence is associated with community health outcomes like mental health and sleep is crucial for developing interventions to mitigate disparities exacerbated by violence exposure. OBJECTIVE: This study examines the associations between community gun violence , insufficient sleep, and poor mental health across neighborhoods in the United States. METHODS: We utilized a novel database covering nearly 16,000 neighborhoods in 100 US cities from 2014 through 2019. Correlated trait fixed-effects models were employed to conduct all analyses while considering various neighborhood covariates such as concentrated disadvantage, demographic composition, population density, and proximity to trauma centers. RESULTS: Our analysis revealed that greater gun violence is associated with both insufficient sleep and poor mental health in subsequent years. There is a reciprocal relationship between poor mental health and insufficient sleep, with each partially mediating the other's association with community gun violence. Notably, gun violence exhibits the strongest direct association with poor sleep rather than with poor mental health. We found a consistent reciprocal relationship between sleep and mental health at the community level. CONCLUSIONS: The findings highlight a complex interplay between community violence, sleep, and mental health, underlining the importance of reducing community violence through numerous long-term interventions to address health disparities across the US.

Justice involvement prediction as individuals age: An age-graded evaluation of the public safety assessment.

OBJECTIVE: Some scholars have criticized pretrial assessments for perpetuating racial bias in the criminal legal system by offering biased predictions of future legal system outcomes. Although these critiques have some empirical support, the scholarship has yet to examine the predictive validity and differential prediction of pretrial assessments across individuals by their age. Following the guidance of the life-course literature, the present study serves as the first age-graded evaluation of the Public Safety Assessment (PSA) focused on assessing whether the predictive validity and scoring predictions of the tool vary across the lifespan. HYPOTHESES: We expected that the predictive validity of the PSA scores would vary across the lifespan, such that the PSA underpredicts for younger individuals and overpredicts for older individuals. METHOD: The present study relied on pretrial information collected from 31,527 individuals during the Advancing Pretrial Policy and Research project. Logistic regression models were estimated to evaluate the differential prediction of the PSA for individuals ranging from 18 to 68 years of age. The results of bivariate models were used to produce area under the curve estimates at each year of age. RESULTS: The results of the present study provided some evidence that the PSA differentially predicted pretrial outcomes for individuals from 18 to 68 years of age. Specifically, the predictive validity of the New Criminal Arrest and the New Violent Criminal Arrest scales appears to improve as individuals become older, suggesting that these instruments are better able to predict pretrial outcomes for older individuals relative to younger individuals. CONCLUSION: The results suggest that the PSA is a valid predictor of pretrial outcomes and that the predictive validity of some PSA scores is impacted by age. These findings suggest that the age of the defendant should be accounted for when interpreting the new criminal arrest and new violent criminal arrest scores. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Youth Incarceration in Adult Facilities and Mental Health in Early Adulthood.

PURPOSE: To examine the relationship between youth incarceration in adult correctional facilities and mental health in early adulthood. METHODS: We analyzed nationally representative data from 1997 through 2019 (N = 8,961) using the National Longitudinal Survey of Youth 1997. An ordinary least squares regression model using inverse probability weights was used to assess the influence of youth incarceration in an adult facility on average mental health scores from age 18 to 37. RESULTS: Respondents incarcerated in an adult facility as a youth had poorer average mental health than those not held in adult prisons or jails over the course of the study period. Those incarcerated for longer in adult facilities also exhibited more mental health symptoms. DISCUSSION: Young people incarcerated in adult correctional facilities experience poorer long-term mental health related to depression and anxiety in early adulthood.

Reciprocal Neighborhood Dynamics in Gun Violence Exposure, Community Health, and Concentrated Disadvantage in One Hundred US Cities.

Gun violence imparts a tremendous human and financial toll on local communities. Researchers have documented extensive mental and physical health consequences of generalized violence exposure but few studies have analyzed the particular impacts of gun violence on community well-being using nationally comprehensive data. We leverage a unique database of almost 16,000 neighborhoods in 100 US cities (2014-2019) to examine how year-over-year rates of gun violence correspond to overall neighborhood well-being and three aspects of community health: (1) health behaviors, (2) physical and mental health status, and (3) health prevention efforts. We simultaneously consider the reciprocal influence of neighborhood well-being on subsequent gun violence while accounting for concentrated disadvantage in communities. The results demonstrate that gun violence is associated with poorer community health in subsequent years, particularly health behaviors and mental/physical health status. Furthermore, we find substantial reciprocal effects for both gun violence and community health in their relationship to neighborhood concentrated disadvantage. These findings highlight the consequential role of gun violence in perpetuating cycles of harm in local communities.

Incarceration of Youths in an Adult Correctional Facility and Risk of Premature Death.

Importance: Youths incarcerated in adult correctional facilities are exposed to a variety of adverse circumstances that could diminish psychological and physical health, potentially leading to early mortality. Objective: To evaluate whether being incarcerated in an adult correctional facility as a youth was associated with mortality between 18 and 39 years of age. Design, Setting, and Participants: This cohort study relied on longitudinal data collected from 1997 to 2019 as part of the National Longitudinal Survey of Youth-1997, a nationally representative sample of 8984 individuals born in the United States between January 1, 1980, and December 1, 1984. The data analyzed for the current study were derived from annual interviews between 1997 and 2011 and interviews every other year from 2013 to 2019 (19 interviews in total). Participants were limited to respondents aged 17 years or younger during the 1997 interview and alive during their 18th birthday (8951 individuals; >99% of the original sample). Statistical analysis was performed from November 2022 to May 2023. Intervention: Incarceration in an adult correctional facility before the age of 18 years compared with being arrested before the age of 18 years or never arrested or incarcerated before the age of 18 years. Main Outcomes and Measures: The main outcome for the study was age at mortality between 18 and 39 years of age. Results: The sample of 8951 individuals included 4582 male participants (51%), 61 American Indian or Alaska Native participants (1%), 157 Asian participants (2%), 2438 Black participants (27%), 1895 Hispanic participants (21%), 1065 participants of other race (12%), and 5233 White participants (59%). A total of 225 participants (3%) died during the study period, with a mean (SD) age at death of 27.7 (5.9) years. Incarceration in an adult correctional facility before the age of 18 years was associated with an increased risk of earlier mortality between 18 and 39 years of age compared with individuals who were never arrested or incarcerated before the age of 18 years (time ratio, 0.67; 95% CI, 0.47-0.95). Being arrested before the age of 18 years was associated with an increased risk of earlier mortality between 18 and 39 years of age when compared with individuals who were never arrested or incarcerated before the age of 18 years (time ratio, 0.82; 95% CI, 0.73-0.93). Conclusions and Relevance: In this cohort study of 8951 youths, the survival model suggested that being incarcerated in an adult correctional facility may be associated with an increased risk of early mortality between 18 and 39 years of age.

Illegal Drug Use, Depressive Symptoms, and General Health: Exploring Co-occurrence across 11 Years in a National Sample.

The co-occurrence of illegal drug use, symptoms of depression, and a lower perception of general health among adolescents continues to be of substantive interest for researchers and the general public alike. Research on this topic, however, remains relatively stagnant, focusing on narrow developmental periods and each association independently, with limited consideration for the existence of a nexus between the three constructs as individuals age. Considering these limitations, the current study examines the longitudinal progression, from adolescence to early adulthood, of illegal drug use, symptoms of depression, and a lower perception of general health. The National Longitudinal Survey of Youth 1997 (NLSY97; N = 8,984), measures over an eleven-year data collection period, and between-and within-individual analytical strategies were used to evaluate the nexus between the constructs. The findings suggested that illegal drug use, depressive symptoms, and general health at previous time periods directly and indirectly predicted illegal drug use, depressive symptoms, and general health at subsequent time periods. Moreover, the within-individual change in illegal drug use was associated with the change in depressive symptoms, and the change in depressive symptoms was associated with the change in general health. Practitioners should consider this co-occurrence when treating symptoms related to illegal drug use, symptoms of depression, and physical health.

Juvenile incarceration in an adult correctional facility as a risk factor for adolescent childrearing?

INTRODUCTION: Recent trends in reproductive rights have contributed to lasting concerns about adolescent childrearing in American society. Beyond being generally unprepared when raising a child, having a child during adolescence is associated with a variety of environmental, social, and psychological consequences for both the parents and the child. It is important to understand the factors contributing to adolescent childrearing. Although research has identified many factors that contribute to adolescent childrearing, a notable gap remains when considering the role of the correctional system and, in particular, the age-specific effects of confining adolescents in adult correctional facilities. METHODS: The current study examined the age-specific effects of time spent in adult correctional facilities from 13 to 34 years of age on childrearing between 14 and 35 years of age using the National Longitudinal Survey of Youth-1997 (NLSY97). The NLSY97 is a nationally representative sample of Males (51%) and Females (49%) born in the United States. Respondents of the NLSY97 were interviewed about life events beginning at age 7 and continued to participate in the study as recently as 2021. RESULTS: The results of the lagged growth curve models suggest that the time spent incarcerated between 13 and 17 years of age heightens the risk of childrearing between 14 and 18 years of age, an effect that is not observed during adulthood. CONCLUSION: Overall, the results suggest that the conditions adolescents are exposed to during incarceration in an adult correctional facility could contribute to a heightened likelihood of adolescent childrearing.

Genetically Adjusted Propensity Score Matching: A Comparison to Discordant MZ Twin Models.

Discordant monozygotic (MZ) twin methodologies are considered one of the foremost statistical approaches for estimating the influence of environmental factors on phenotypic variance. Limitations associated with the discordant MZ twin approach generates an inability to estimate particular relationships and adjust estimates for the confounding influence of gene-nonshared environment interactions. Recent advancements in molecular genetics, however, can provide the opportunity to address these limitations. The current study reviews an alternative technique, genetically adjusted propensity scores (GAPS) matching, that integrates observed genetic and environmental information to adjust for the confounding of these factors in nonkin individuals. Simulations and a real data example were used to compare the GAPS matching approach to the discordant MZ twin method. Although the results of the simulated comparisons demonstrated that the discordant MZ twin approach remains the more robust statistical technique to adjust for shared environmental and genetic factors, GAPS matching - under certain conditions - could represent a viable alternative when MZ twin samples are unavailable. Overall, the findings suggest that GAPS matching can potentially provide an alternative to the discordant MZ twin approach when limited variation exists between identical twin pairs. Moreover, the ability to adjust for gene-nonshared environment interactions represents a potential advancement associated with the GAPS approach. The limitations of the approach, as well as polygenic risk scores, are also discussed.

Exploring the Correspondence Between General Correctional Programming and Inmate Misconduct Using a Time-Course Framework.

Inmate misconduct continues to threaten safety and order within correctional institutions. Yet few studies have examined its longitudinal nature. In this paper we explore the correspondence between correctional programming and inmate misconduct. To do this, we draw from Linning et al.'s time-course framework devised to improve the design and evaluation of interventions by considering effects that can occur before, during, and after programming. We provide the first empirical demonstration of their framework using prisoner misconduct data collected from all Ohio prisons between January 2008 and June 2012. A cross-lagged panel analysis provides support for the use of a time-course framework. Results show that misconduct decreased during programming. However, we observed increases in misconduct prior to and following exposure to programming. Our results suggest that future work needs to improve our understanding of causal mechanisms of inmate misconduct and when their effects are expected.

Heteropaternal Siblings Misclassified as Dizygotic Twins: A Potential Biasing Factor for Heritability Estimates?

Heteropaternal superfecundation (HP) occurs when two or more ova are fertilized by sperm from separate males. The resulting siblings are genetically equivalent to half-siblings and share, on average, 25% of their inherited genetic material. In the absence of genetic testing HP siblings could be treated as dizygotic (DZ) twins in behavioral genetic analyses and bias heritability estimates in phenotypic decomposition models. However, the extent to which such misclassification could affect calculated estimates of heritability is currently unknown. Employing simulation analyses, the current study assessed the potential biasing impact across a variety of conditions varying by proportions of DZ twins, sample sizes, and low, moderate, and high levels of genetic and environmental contribution to phenotypic variance. Overall, the results indicated that misclassified HP siblings had minimal impact on estimates of heritability. Nonetheless, greater attention should be paid to the identification of HP siblings within existing and future twin datasets.

The Association Between Adolescent Gun Ownership and Gun Carrying and Adulthood Violence and Victimization.

Although many studies have highlighted the deleterious outcomes associated with access to firearms, others suggest gun ownership and carrying can have protective effects. This study attempts to adjudicate between these countervailing points and address several important gaps in the literature. To do so, data from the National Longitudinal Study of Adolescent to Adult Health were used to assess the long-term associations between gun ownership and gun carrying in late adolescence and violence and violent victimization in early adulthood. Results from propensity score matching analyses suggest gun carrying, but not gun ownership, is associated with a higher risk of experiencing a violent victimization (b = 0.080, 95% CI = .032, .127) and engaging in violence with a weapon (b = 0.885, 95% CI = .392, 1.378). Efforts to curb firearm-related violence should consider focusing on those who carry guns for additional counseling about these risks.

Traumatic brain injury and adverse psychological effects: Examining a potential pathway to aggressive offending.

Contemporary scholarship has demonstrated an association between traumatic brain injury (TBI) during adolescence and aggressive offending. Research, however, has yet to identify any mechanisms linking TBI to subsequent aggressive offending. Consequently, the current study hypothesized that adverse psychological effects is one such pathway. The current study used the Pathways to Desistance data set (n = 416) to examine the pathway of TBI to aggressive offending through adverse psychological effects. The findings of the structural equation model supported the hypothesized association. Specifically, increased exposure to TBI was indirectly associated with aggressive offending through adverse psychological effects. An additional supplemental analysis illustrated that a direct link between TBI and aggressive offending did not exist for the analytical sample. The findings suggested that the neurological disruptions commonly associated with TBI could result in direct increases in negative psychological outcomes and indirect increases in subsequent negative behavioral outcomes.

Self-reported traumatic brain injury during key developmental stages: examining its effect on co-occurring psychological symptoms in an adjudicated sample.

Primary Objective: Prior research has demonstrated that traumatic brain injury (TBI) is associated with individual psychological symptoms. These findings, however, may not pertain to the influence of TBI during key developmental stages on the co-occurrence of negative psychological symptoms.Research Design: It was hypothesized that (H1) self-reported TBI is associated with adverse psychological effects, that (H2) self-reported TBI during adolescences is associated with both immediate and delayed adverse psychological effects, and finally, (H3) self-reported TBI during the early stages of adulthood is not associated with immediate psychological effects.Methods and Procedures: The current study employed a sample of adjudicated youth (N: 419 to 562) and structural equation modeling to estimate the association between self-reported TBI and subsequent adverse psychological effects.Results: Findings suggested that higher levels of self-reported TBI during adolescence were associated with higher levels of adverse psychological effects. These effects were both immediate and delayed. However, higher levels of self-reported TBI during adulthood were not associated with immediate adverse psychological effects.Conclusion: Overall, the findings suggest that deleterious outcomes related to self-reported TBI during key developmental stages include proximal and long-term adverse psychological effects.

The role of three-dimensional pure bovine gelatin scaffolds in tendon healing, modeling, and remodeling: an in vivo investigation with potential clinical value.

AIM OF THE STUDY: Large tendon defects involving extensive tissue loss present complex clinical problems. Surgical reconstruction of such injuries is normally performed by transplanting autogenous and allogenous soft tissues that are expected to remodel to mimic a normal tendon. However, the use of grafts has always been associated with significant limitations. Tissue engineering employing artificial scaffolds may provide acceptable alternatives. Gelatin is a hydrolyzed form of collagen that is bioactive, biodegradable, and biocompatible. The present study has investigated the suitability of gelatin scaffold for promoting healing of a large tendon-defect model in rabbits. MATERIALS AND METHODS: An experimental model of a large tendon defect was produced by partial excision of the Achilles tendon of the left hind leg in adult rabbits. To standardize and stabilize the length of the tendon defect a modified Kessler core suture was anchored in the sectioned tendon ends. The defects were either left untreated or filled with three-dimensional gelatin scaffold. Before euthanasia 60 days after injury, the progress of healing was evaluated clinically. Samples of healing tendon were harvested at autopsy and evaluated by gross, histopathologic, scanning, and transmission electron microscopy, and by biomechanical testing. RESULTS: The treated animals showed superior weight-bearing and physical activity compared with those untreated, while frequency of peritendinous adhesions around the healing site was reduced. The gelatin scaffold itself was totally degraded and replaced by neo-tendon that morphologically had significantly greater numbers, diameters, density, and maturation of collagen fibrils, fibers, and fiber bundles than untreated tendon scar tissue. It also had mechanically higher ultimate load, yield load, stiffness, maximum stress and elastic modulus, when compared to the untreated tendons. CONCLUSION: Gelatin scaffold may be a valuable option in surgical reconstruction of large tendon defects.

Effectiveness of hybridized nano- and microstructure biodegradable, biocompatible, collagen-based, three-dimensional bioimplants in repair of a large tendon-defect model in rabbits.

This study was designed to investigate the effectiveness of hybridized, three-dimensional (3D) collagen implants in repair of experimentally-induced tendon defects in rabbits. Seventy-five mature New Zealand albino rabbits were divided into treated (n = 50) and control (n = 20) groups. The left Achilles tendon was completely transected and 2 cm excised. In treated animals defects were filled with hybridized collagen implants and repaired with sutures. In control rabbits tendon defects were sutured similarly but the gap was left untreated. Changes in injured and normal contralateral tendons were assessed weekly by ultrasonography. Among the treated animals, small pilot groups were euthanized at 5, 10, 15, 20, 30, 40 (n = 5 at each time interval) and the remainder (n = 20) at 60 days post-injury. All control animals were euthanized at 60 days. Tendon lesions of all animals were examined morphologically and histologically immediately after death. Those of the experimental groups (n = 20 for each) were examined for gross pathological, histopathological and ultrastructural changes together with dry matter content at 60 days post-injury, as were the normal, contralateral tendons of both groups. In comparison with healing lesions of control animals, the treated tendons showed greater numbers of mature tenoblasts and tenocytes, minimal peritendinous adhesions and oedema, together with greater echogenicity, homogeneity and fibril alignment. Fewer chronic inflammatory cells were present in treated than control tendons. Hybridized collagen implants acted as scaffolds for tenoblasts and longitudinally-orientated newly-formed collagen fibrils, which encouraged tendon repair with homogeneous, well-organized highly aligned scar tissue that was histologically and ultrastructurally more mature than in untreated controls. Copyright © 2016 John Wiley & Sons, Ltd.

Novel application of a tissue-engineered collagen-based three-dimensional bio-implant in a large tendon defect model: a broad-based study with high value in translational medicine.

This study was designed to investigate the effectiveness of a novel tissue-engineered three-dimensional collagen implant on healing of a large tendon-defect model, in vivo. Forty rabbits were divided into two equal groups: treated and control. A 2cm full-thickness gap was created in the left Achilles tendons of all the rabbits. To maintain the gap at the desired length (2cm), a Kessler suture was anchored within the proximal and distal ends of the remaining tendon. In the treated group a collagen implant was inserted in the gap while in the control group the gap was left unfilled. At weekly intervals the animals were examined clinically and their Achilles tendons tested bioelectrically. The hematological parameters and the serum Platelet-Derived Growth Factor of the animals were analyzed at 60 days post injury (DPI) immediately prior to euthanasia. Their injured (left) and normal contralateral Achilles tendons were harvested and examined at gross morphologic level before being subjected to biomechanical testing, and biophysical and biochemical analysis. The treated animals showed superior weight-bearing and greater physical activity than their controls. New dense tendinous tissue with a transverse diameter comparable to that of intact tendons filled the defect area of the treated tendons and had entirely replaced the collagen implant, at 60 DPI. In control lesions the defect was filled with loose areolar connective tissue similar to subcutaneous fascia. Treatment significantly improved the electrical resistance, dry matter, hydroxyproline content, water uptake and water delivery characteristics, of the healing tissue, as well as maximum load, yield load, maximum stress, yield stress and modulus of elasticity of the injured treated tendons compared to those of the control tendons (P<0.05). Use of this three-dimensional collagen implant improved the healing of large tendon defects in rabbits.

Experimental Validation of Methods for Prophylaxis against Deep Venous Thrombosis: A Review and Proposal.

The experimental procedure by which the valve cusp hypoxia (VCH) hypothesis of the etiology of deep venous thrombosis (DVT) was confirmed lends itself to testing of methods of prophylaxis. Similar animal experiments could end the present exclusive reliance on statistical analysis of data from large patient cohorts to evaluate prophylactic regimes. The reduction of need for such (usually retrospective) analyses could enable rationally-based clinical trials of prophylactic methods to be conducted more rapidly, and the success of such trials would lead to decreased incidences of DVT-related mortality and morbidity. This paper reviews the VCH hypothesis ("VCH thesis", following its corroboration) and its implications for understanding DVT and its sequelae, and outlines the experimental protocol for testing prophylactic methods. The advantages and limitations of the protocol are briefly discussed.

Metrenperone enhances collagen turnover and remodeling in the early stages of healing of tendon injury in rabbit.

INTRODUCTION: This study evaluated the effects of metrenperone on healing of unilateral, collagenase-induced lesions in the Superficial Digital Flexor Tendons (SDFT) of rabbits. METHODS: After controlled injury of the left SDFT, nine rabbits received daily treatment with metrenperone for 28 days. Another nine were untreated controls; in both groups the contra-lateral tendons served as uninjured controls. Histological and ultrastructural changes, mechanical properties, dry weight, collagen content, and amount of DNA in healing and control tendons were assessed 28 days after injury. RESULTS: Restoration of structural hierarchy was more organized in treated than in untreated tendons while cellularity was greater in the latter. At the ultrastructural level, collagen in treated lesions was predominantly in the form of small-diameter, new fibrils, with few large, old fibrils; in untreated lesions there was a high proportion of large, old fibrils but relatively few small, new ones. The amount of DNA in untreated injuries was much greater than in normal tendons, while in treated lesions it was not significantly different from that of uninjured controls. There were no significant differences in total collagen, stiffness and ultimate strength of injured, treated, and untreated tendons 28 days after injury. Both were significantly weaker than their corresponding contralaterals. CONCLUSIONS: The findings suggest that metrenperone had positive effects on collagen turnover, remodelling, and organization during acute inflammation and fibroplasia. Provided that the new fibrils subsequently matured in a normal manner, mechanical characteristics of the organized scar should be better than those of an untreated lesion.

Effects of a serotonin S2-receptor blocker on healing of acute and chronic tendon injuries.

The beneficial effects of serotonin S(2)-receptor blockers on healing skin and muscle ulcers and refractory lesions such as leprosy and diabetic and ischemic ulcers have been reported previously, but their mechanisms of actions are not clear. The present study sought to elucidate the action of an S(2)-receptor blocker, metrenperone, on the healing of collagenase-induced injuries in superficial digital flexor tendons of two groups of rabbits. In one group, oral and topical therapy for 28 days with metrenperone, was started within 48 hr of a single acute injury. The animals were then left untreated for another 60 days, when it was found that most of the morphological, biochemical, and biomechanical characteristics of the healed tendons matched those of their normal uninjured controls. Injured, untreated controls showed poor healing. In the second group of animals, tendon injury was induced by four separate injections of collagenase at weekly intervals. The rabbits were left for another 60 days, before being treated with metrenperone for 26 days. This delayed treatment had no apparent effect on the biomechanical, biochemical, or morphological characteristics of the healing tendons. It appeared that metrenperone had a significant effect on collagen turnover and organization of scar tissue, but only while the inflammatory and fibroplastic processes were active in the early stages of healing. S(2)-receptor blockers may, therefore, be of potential value for modulating repair in acutely injured collagenous tissue.

Response of a collagenase-induced tendon injury to treatment with a polysulphated glycosaminoglycan (Adequan).

This study explored the hypothesis that local administration of a polysulphated glycosaminoglycan (PSGAG) in the early phase of healing of a standard collagenase-induced tendon injury in the superficial digital flexor tendon of the rabbit would reduce the degenerative effects of inflammatory mediators and proteases and preserve normal tendon morphology, composition, and biomechanical properties. Histological and ultrastructural changes together with the mechanical properties, dry weight, collagen content, and amount of DNA in healing tissue at the site of the lesion were assessed in treated and untreated animals. In treated lesions 28 days after injury, the normal orientation of tenoblasts and collagen fibrils was well preserved compared with the disorganized scar formation seen in untreated animals. The degree of cellularity was significantly higher in the untreated lesions. At the ultrastructural level the collagen in the healing tissue of the treated animals consisted of a mixture of small diameter, new regenerated fibrils intermingled with well-preserved large diameter, old fibrils, aligned to the long axis of the tendon; in untreated animals small, randomly arranged new fibrils predominated. The diameters of treated tendons had returned to normal, but in untreated animals the injured tendons remained significantly thicker than their controls. The percentage dry weight and collagen contents of treated injured tendons approximated those of control normal tendons, whereas those of untreated tendons were significantly less than those of the control values. The DNA content of injured treated tendons was not significantly different from that of normal contralateral controls, while in the untreated tendons it was significantly higher. There were no significant differences between the normal and the contralateral treated injured tendons in ultimate strength, fatigue strength, stiffness, and maximum absorbed energy. However in the untreated animals, although the tendon diameter was significantly greater, the ultimate strength, fatigue strength, stiffness, and maximum absorbed energy were significantly lower than the contralateral control. These data suggest that polysulphated glycosaminoglycans are effective in restoring the morphological, biochemical, and biomechanical properties of injured soft connective tissues and may be of clinical value in the treatment of acute tendon injury.