Internal Disruption Research Articles

Paintball Trauma and Mechanisms of Optic Nerve Injury: Rotational Avulsion and Rebound Evulsion

Ballistic impact studies and supercomputer modeling were performed to elicit the mechanisms of optic nerve rupture that may accompany blunt ocular trauma. Paintball ocular impact responses were studied with abattoir-fresh porcine eyes. Physics-based numerical code CTH was used to produce robust geometric and constitutive models of the eye and orbit, providing a comparative 3-D finite volume model to help determine the mechanisms underlying empirical ballistic observations. Among 59 porcine eye specimens submitted to paintball impact in the 1- to 13-J range, 10 (17%) disengaged completely from the orbital mount. In each instance the paintball penetrated the orbit adjacent to the globe, producing rotation and eventual globe repulsion, dramatically evident on high-speed film images. Supercomputer modeling yielded similar globe-expulsive results when orbital constraints were in place, but not when these were removed. In these models, tangential (grazing) impact sheared the nerve flush with the globe via a strain rate effect within 260 μs, with minimal posterior displacement and just 5° of globe rotation. Midperipheral impact produced compressive globe distortion and posterior displacement, followed by rebound and tractional nerve avulsion 10 mm behind the lamina after 700 μs and 20° of globe rotation. Constitutive modeling studies suggest at least two trajectory-dependent mechanisms for optic nerve rupture with paintball impact on the eye. Tangential glancing blows produce strain-rate rotational avulsion, abscising the optic nerve with minimal internal globe disruption, whereas off-center direct impact produces slower rotational-rebound evulsion, traumatizing the globe and breaching the nerve posteriorly. The latter mechanism would be expected to arise more commonly and would most likely be clinically masked by accompanying intraocular injury.

Diagnostic Discography: What is the Clinical Utility?

The diagnosis and treatment of discogenic back pain is challenging. Provocation discography, an invasive spinal procedure, has been suggested as a diagnostic test for internal disc disruption to provide information on disc morphology and reproduction of symptoms. Current applications consist of the evaluation of persistent spinal pain in individuals, including postoperative patients, as well as providing a guide for patient selection for spinal fusion surgery and minimally invasive interventional pain procedures. While the validity of discography has been questioned by multiple scientific studies, technical refinements have addressed many of the initial limitations. An updated review on the safety and utility of discography will be provided, covering key areas of debate including false-positive rates, technical parameters, clinical utility, and risk of discography procedural-related intervertebral disc damage.

Intradiscal electrothermal therapy for symptomatic internal disc disruption: 24-month results and predictors of clinical success. Assietti R, Morosi M, Block JE. J Neurosurg Spine 2010;12(3):320–6.

Intradiscal electrothermal therapy for symptomatic internal disc disruption: 24-month results and predictors of clinical success. Assietti R, Morosi M, Block JE. J Neurosurg Spine 2010;12(3):320–6.

Snake instability in the plasma of the Globus-M spherical tokamak

Experiments with the limiting density of a plasma generated in the Globus-M spherical tokamak operating in the ohmic heating regime show that, when the plasma density reaches a certain value at the center of the plasma filament, snake-type strong magnetohydrodynamic instability exciting the m/n = 1/1 mode arises. A further rise in the density causes an internal disruption of the plasma. Numerical simulation of the instability dynamics is performed, and the results of simulation are compared with experimental and theoretical data. Experimental and theoretical data are in good agreement. It is shown that the instability is associated with an increased amount of impurities in the plasma and that the limit in density is of a “technological,” rather than of a fundamental, character. With the vacuum chamber cleaned more thoroughly, this limit disappears and the snake instability is not observed. Accordingly, a plasma filament density of 1 × 1020m−3 was attained with a Greenwald number as high as 95%.

Annular tears, fissures or HIZ?

Low back pain (LBP) is an acute or chronic pain in the lumbar or sacral regions [1], is highly prevalent and has substantial socioeconomic implications [2]. Jensen et al noted that low back pain is the second most common reason that patients seek medical care in the United States and that the estimated annual cost of related medical care is more than $8 billion [3]. Robertson noted also that the rate of low back–related disability has grown at a rate 14 times that of the population during the last 30 years [3]. MRI is established as the investigation of choice for assessing patients presenting with low back pain (LBP) and sciatica; recognised causes of nerve root compression include disc herniation and spinal stenosis, however many patients presenting with LBP and pain referred to the lower limb(s) show no evidence on imaging studies of nerve root compression, suggesting that there are other factors involved in the production of pain [4]. One of the prominent somatic sources of low back pain is the internal disc disruption of the lumbar spine, the socalled discogenic lumbar pain, which is the condition causing back pain without radiculopathy [5]. The annulus fibrosus is innervated by the recurrent meningeal nerve and by the small branches from the ventral ramus of the somatic spinal nerve; a proposed mechanism for such pain is inflammation of nerve roots (chemical radiculopathy) from leak of degenerative nuclear material through full-thickness annular tears [4, 5]. Compared with asymptomatic disks, painful disrupted lumbar intervertebral disks have higher concentrations of sensory fibers in their endplates and nucleus; this high concentration of sensory fibers, combined with increased levels of proinflammatory mediators such as IL-8 and PGE2, provides a substrate for hyperalgesia and presumably pain [6]. In this hyperalgesic state, even normal mechanical loading will be painful [6]. The concept of diskogenic pain caused by nocioceptive ingrowth into annular fissures has been supported only indirectly by observing a strong correlation between pain provocation and the presence of annular fissure during provocation diskography and subsequent CT imaging; annular fissures reaching the outer annular fibers are in fact the source of symptoms in patients suffering from chronic diskogenic LBP [6]. Discogenic lumbar pain is characterized by nonradicular pain, has a somatotropic rather than dermatomal pattern of pain projection; therefore, the use of symptoms and clinical findings to localize the level of abnormality is difficult; the source of discogenic pain is still unknown [7]. Ideally, a history and physical examination would consistently diagnose the source of a patient’s low back pain, and, if one diagnosed pain secondary to the intervertebral disc, one would be able to identify the exact level or levels involved; in reality, however, the exact source of low back pain is often illusive, because discogenic pain projects in a somatotropic rather than a dermatomal pattern, confirming and localizing a discogenic source, much less the exact level, using clinical findings alone remains unproven [8]. MR imaging provides an unique means to evaluate the morphologic status of intervertebral disks and their relationship to neural structures in patients with low back pain; moreover, the technique allows assessment of the biochemical status of the disk on T2-weighted spin-echo and fast spin-echo MR images [7]. One of the first structural abnormalities that predicted concordant pain provocation during disc stimulation was high-signal-intensity zones (HIZ) at first described by Aprill and Bogduk in 1992 [8]. HIZ are defined as small foci of high signal intensity at:

Percutaneous Treatment of Lumbar Intervertebral Disc Hernias with Discogel

A new percutaneous technique for the treatment of the backache and sciatica related to the lumbar disc herniation was applied in 34 patients at 40 levels. The technique is easy, safe, efficacious and without complications. In particular it is useful for the diagnosis and treatment of the underestimated "internal disc disruption" syndrome.

A simulation approach for a periodic PCR buffer allocation strategy in organizational program management

In a dynamically changing environment, the manager of a maintenance and remodeling (M/R) program is confronted with an increasing complexity of coordinating and cooperating multi-resource constrained multiple projects. Uncertainty and interdependence are sources of the complexity, and cause an internal disruption of an activity and chain reactions of disturbance propagation that deteriorate the stability and manageability of the program. This paper evaluates previous endeavors to apply production control and management techniques to the construction industry, and investigates the possibility of applying other production concepts and theories to organizational program management. In particular, this paper proposes a buffer allocation strategy by which periodic buffers are allocated in the flows of program constraint resources (PCRs) to stabilize a master construction schedule instead of protecting individual activities. Comparative experiments by Monte Carlo simulations illustrate better performance of the proposed strategy in terms of program goals: productivity, flexibility, and long-term stability.

Etiology of Chronic Low Back Pain in Patients Having Undergone Lumbar Fusion

To estimate the prevalence of lumbar internal disc disruption, zygapohyseal joint pain, sacroiliac joint pain, and soft tissue irritation by fusion hardware in post-fusion low back pain patients compared with non-fused patients utilizing diagnostic spinal procedures. Retrospective chart review. University spine center. Patients presenting to a community-based, multidisciplinary, academic spine center (65.9% female, mean age 54.4 years, median pain duration 12 months). Charts of consecutive low back pain cases completing diagnostic spinal procedures including provocation discography and zygapohyseal joint, sacroiliac joint, and fusion hardware blockade were retrospectively reviewed. Based on the results of discography and/or diagnostic blockades, subjects were classified with internal disc disruption, zygapohyseal joint pain, sacroiliac joint pain, or fusion hardware related pain. The diagnoses of 28 fusion cases identified from 170 low back pain patients undergoing diagnostic procedures included 12 with sacroiliac joint pain, seven with internal disc disruption, five with zygapohyseal joint pain, and four due to soft tissue irritation from fusion hardware. No significant differences were noted in zygapohyseal joint mediated pain with and without fusion history. Mean ages of patients were similar with and without fusion history for cases diagnosed as internal disc disruption. In patients' recalcitrant to non-interventional care, the sacroiliac joint is the most likely source of low back pain after lumbar fusion followed by internal disc disruption, zygapohyseal joint pain, and soft tissue irritation due to fusion hardware. Sacroiliac joint pain is more common after fusion, while internal disc disruption is more common in non-fusion patients.

The eastern slope of the southern Adriatic basin: a case study of submarine landslide characterization and tsunamigenic potential assessment

The southern Adriatic basin is the current foredeep of the Albanide fold-and-thrust belt that runs along the eastern boundary of the Adriatic basin and partly owes its remarkable water depth, deeper than 1,000 m, to the Mesozoic palaeogeography of the region. The eastern slope of the southern Adriatic basin is characterized by a thick stack of sedimentary prograding units, fed by sediments coming from the adjacent fold-and-thrust belt, which is still seismically active (e.g. 1979 Montenegro, M = 6.8). This slope presents extensive evidence of large-scale mass wasting throughout its Quaternary evolution and appears as a destructive slope system affected by progressive retreat. A submarine slide located along the eastern slope of the southern Adriatic basin has been recently characterized with good detail. The slide is of relatively small volume (0.031 km3) and shows a limited displacement, without major internal disruption. The small volume of the landslide combined with its relatively large water depth (headscarp at about 560 m and deposit at 700 m) result in a limited tsunamigenic potential, that has been assessed numerically by means of a Lagrangian block model as regards the slide motion and through a shallow-water finite-difference code for the tsunami waves propagation. Despite the almost negligible tsunami effects, the studied landslide can be taken as a lower case limit for other events along the scarp, and the observed features concerning the generated wave and its impact on the coast can be considered valid also for bigger events.

Impact of nano titanium dioxide exposure on cellular structure of Anabaena variabilis and evidence of internalization

The present study investigated the impact of nano titanium dioxide (nTiO(2) ) exposure on the cellular structures of the nitrogen-fixing cyanobacteria Anabaena variabilis. Results of the present study showed that nTiO(2) exposure led to observable alteration in various intracellular structures and induced a series of recognized stress responses, including production of reactive oxygen species (ROS), appearance and increase in the abundance of membrane crystalline inclusions, membrane mucilage layer formation, opening of intrathylakoidal spaces, and internal plasma membrane disruption. The production of total ROS in A. variabilis cells increased with increasing nTiO(2) doses and exposure time, and the intracellular ROS contributed to only a small fraction (<10%) of the total ROS measured. The percentage of cells with loss of thylakoids and growth of membrane crystalline inclusions increased as the nTiO(2) dose and exposure time increased compared with controls, suggesting their possible roles in stress response to nTiO(2) , as previously shown for metals. Algal cell surface morphology and mechanical properties were modified by nTiO(2) exposure, as indicated by the increase in cell surface roughness and shifts in cell spring constant determined by atomic force microscopy analysis. The change in cell surface structure and increase in the cellular turgor pressure likely resulted from the structural membrane damage mediated by the ROS production. Transmission electron microscopy (TEM) analysis of nTiO(2) aggregates size distribution seems to suggest possible disaggregation of nTiO(2) aggregates when in close contact with microbial cells, potentially as a result of biomolecules such as DNA excreted by organisms that may serve as a biodispersant. The present study also showed, for the first time, with both TEM and Raman imaging that internalization of nTiO(2) particles through multilayered membranes in algal cells is possible. Environ. Toxicol. Chem. 2011; 30:861-869. © 2010 SETAC.

What Is the Source of Chronic Low Back Pain and Does Age Play a Role?

The objective of this study was to estimate the prevalence, mean age, and association of prevalence and age of lumbar internal disc disruption (IDD), facet joint pain (FJP), sacroiliac joint pain (SIJP), spinal and pelvic insufficiency fractures, interspinous ligament injury/Baastrup's Disease, and soft tissue irritation by fusion hardware. The study's design was a retrospective chart review. The study was set in an academic spine center. A total of 378 cases from 358 patients were reviewed of which 170 cases from 156 patients who underwent diagnostic procedures were included. Discography, dual diagnostic facet joint blocks, intra-articular sacroiliac joint injections, anesthetic injections of painful interspinous ligaments/opposing spinous processes/posterior fusion hardware, or percutaneous augmentation were performed. Prevalence and age were analyzed for each diagnosis group. Patients with recalcitrant low back pain underwent diagnostic procedures based on their clinical presentation until the pain source was identified. The prevalence of internal disc disruption, facet joint pain and sacroiliac joint pain was 42%, 31%, and 18%, respectively. Patients with internal disc disruption were significantly younger than those with facet joint pain or sacroiliac joint pain. Increased age was associated with a decreased probability of internal disc disruption and increased probabilities of facet joint pain and sacroiliac joint pain as the source of low back pain until approximately age 70. Our data confirm the intervertebral disc as the most common etiology of chronic low back pain in adults. Based on our sample, the younger the patient, the more likely low back pain is discogenic in origin. Facetogenic or sacroiliac joint pain is more likely in older patients.

Does the Location of Low Back Pain Predict Its Source?

To evaluate the predictive utility of the pattern of low back pain (LBP) in detecting the source of LBP as internal disk disruption (IDD), facet joint pain (FJP), or sacroiliac joint pain (SIJP). Retrospective chart review. University spine center. A total of 170 cases from 156 patients presenting with LBP whose low back disorder was definitively diagnosed. The mean age was 54.4 years (SD, 16.2) and median duration of LBP was 12 months (interquartile ranges, 6-32). Charts of consecutive LBP patients who underwent definitive diagnostic spinal procedures including provocation diskography, facet joint blocks, and sacroiliac joint blocks were retrospectively reviewed. Each patient with LBP was queried as to the exact location of their LBP: midline, defined as in-line with the spinous processes, and/or paramidline, defined as lateral to 1 fingerbreadth adjacent to the midline. In patients with a definitive diagnosis for the source of LBP, the proportion of each diagnosed source of pain was calculated. χ(2) tests were used to identify differences in the percentages of midline and paramidline LBP among the groups of patients testing positive for IDD, FJP, or SIJP. Diagnostic measures of sensitivity, specificity, positive and negative predictive values, diagnostic accuracy, and likelihood ratios of positive and negative tests using the presence/absence of midline and paramidline pain for the diagnosis of IDD, FJP, and SIJP were estimated. With cases of IDD, significantly greater percentages of patients reported midline LBP (95.8%; χ(2) = 101.4, df = 2, P < .0001) as compared with cases of FJP (15.4%) or SIJP (12.9%). In cases of IDD, significantly lower percentages of patients reported paramidline pain (67.3%; χ(2) = 16.1, df = 2, P = .0003) as compared with cases of FJP (95.0%) or SIJ (96.0%). In cases of IDD, significantly greater percentages of patients reported midline LBP (95.8%; χ(2) = 101.4, df = 2, P < .0001) as compared with cases of FJP (15.4%) or SIJP (12.9%). The specificity of midline LBP for IDD, FJP, and SIJP was 74.8% (95% CI = 65.0%-82.9%), 28.0% (20.1%-37.0%), and 36.0% (28.0%-44.5%), respectively. The negative predictive value of paramidline LBP for IDD, FJP, and SIJP was 29.2% (95% CI = 12.6%-51.1%), 91.7% (73.0%-99.0%), and 95.8% (78.9%-99.9%). The diagnostic accuracy of midline LBP for IDD, FJP, and SIJP was 83.5%, 24.1%, and 31.8%, respectively. The presence of midline LBP increases the probability of lumbar IDD and reduces the probability of symptomatic FJ and SIJ dysfunction. The presence of isolated paramidline LBP increases the probability of symptomatic FJ or SIJ but mildly reduces the likelihood of lumbar IDD.

Democracy, Gender Equality, and Customary Law: Constitutionalizing Internal Cultural Disruption

Customary law often includes gender discriminatory rules that violate women’s rights under constitutional equality guarantees. Dialogic democracy theory offers valuable tools that can help a legal system both to protect customary law and to protect the equality of its women citizens. By focusing on the need for challenge and on the dialogue within the cultural community, the legal system can create incentives and conditions to support the capacity of women to shape the customary law of their own communities. This approach is necessary because legal rights for women, when imposed by the larger society, often result in backlash within minority communities. In the long run, the structural inequality of women cannot be addressed by legal rights alone, but must be addressed by programs that seek to give women the power within their communities to achieve their own equality.

6-Month Results of Transdiscal Biacuplasty on Patients with Discogenic Low Back Pain: Preliminary Findings

Prospective observational study. Our aim is to investigate the efficacy and safety of TransDiscal Biacuplasty. Chronic discogenic pain is one of the leading causes of low back pain; however, the condition is not helped by most non-invasive methods. The results of major surgical operations for these patients are unsatisfactory. Recently, attention has shifted to disk heating methods for treatment. TransDiscal Biacuplasty is one of the minimally invasive treatment methods. The method was developed as an alternative to spinal surgical practices and Intradiscal Electrothermal Therapy for treatment of patients with chronic discogenic pain. The candidates for this study were patients with chronic discogenic pain that did not respond to conservative treatment. The main criteria for inclusion were: the existence of axial low back pain present for 6 months; disc degeneration or internal disc disruption at a minimum of one level, and maximum of two levels, in MR imaging; and positive discography. Physical function was assessed using the Oswestry Disability Index when measuring the pain with VAS. Patient satisfaction was evaluated using a 4-grade scale. Follow-ups were made 1, 3, and 6 months after treatment. 15 patients were treated at one or two levels. The mean patient age was 43.1 ± 9.2 years. We found the mean symptom duration to be 40.5 ± 45.7 months. At the sixth month, 57.1% of patients reported a 50% or more reduction in pain, while 78.6% of patients reported a reduction of at least two points in their VAS values. In the final check, 78.6% of patients reported a 10-point improvement in their Oswestry Disability scores compared to the initial values. No complications were observed in any of the patients. TransDiscal Biacuplasty is an effective and safe method.

ISSLS Prize Winner: How Loading Rate Influences Disc Failure Mechanics

Mechanically induced disruption and subsequent microscopic investigation of lumbar intervertebral discs following a previously published testing protocol, but using a much higher rate of loading. To explore if loading rate affects the internal disruption mechanics of lumbar intervertebral discs. The failure mechanics of some bone-ligament-bone constructs vary with the rate of tensile load application. Like many ligaments, recent reports indicate that the mechanical response of the disc wall varies with strain-rate. It is possible that the internal failure mechanics of the disc wall also varies with strain-rate. Nuclear pressurization was used to deliver sudden pressure impulses directly to the nucleus of ovine lumbar motion segments. Pressure impulses were delivered to 12 neutrally positioned motion segments, and 15 motion segments held at 7° flexion. Aside from loading rate, testing was conducted in the same manner as 2 previously published studies that employed a gradual nuclear pressurization regime. Following testing, the internal damage resulting to each disc was analyzed using micro-CT and serial microscopy in tandem. Radial tears of the medioposterior disc wall were the most frequent cause of disc failure. In most cases, radial tears involved a combination of annular and endplate disruption: Neutrally positioned discs frequently suffered tears within the superior cartilaginous endplate adjacent to the transition zone and/or inner anulus. Flexed discs frequently suffered tears adjacent to the outer anulus at the cartilaginous/vertebral endplate junction, or within the vertebral endplate. Both groups frequently suffered endplate tears adjacent to the mid anulus at the inferior cartilaginous/vertebral endplate junction. The internal morphologies of the disc disruptions created in this study using high strain-rate impulse pressurization differed significantly from those documented previously for both neutrally positioned and flexed discs subjected to gradual low strain-rate pressurization. These morphologic differences show that the internal failure mechanics of lumbar intervertebral discs vary with the rate of internal radial load application.

Sacral Neuromodulation in Children With Urinary and Fecal Incontinence: A Multicenter, Open Label, Randomized, Crossover Study

The clinical benefit of sacral neuromodulation is unclear due to the paucity of randomized trial data. The purpose of this study was to evaluate sacral neuromodulation for management of urinary and fecal incontinence in a pediatric population. This multicenter, open label, randomized, crossover study included children older than 5 years. After trial stimulation of the S3 root a neuromodulator (InterStim) was implanted on the S3 foramen. Clinical examinations, voiding and bowel diaries, and urodynamic and manometric evaluations were performed at the beginning (t1) and end (t2) of the first period, and at the beginning (t3) and end (t4) of the second period. A total of 33 patients (24 boys) with a mean +/- SD age of 12.22 +/- 5.09 years were randomized. Etiologies were mainly of neurological origin. Incontinence was mixed urinary and fecal in 19 cases, urinary only in 9 and fecal only in 5. Cystometric bladder capacity increased during sacral neuromodulation (delta +24.27 ml vs -37.45 ml, p = 0.01). There was no significant change in other urodynamic or manometric parameters. Overall positive response rate was more than 75% for urinary (81%) and bowel (78%) function. Crossover analysis indicated that sacral neuromodulation is more effective than conservative treatment for both types of incontinence (p = 0.001). In a pediatric population sacral neuromodulation is effective for bladder and bowel dysfunction and should be considered before irreversible surgery.

Vacuolated oocytes: fertilization and embryonic arrest following intra-cytoplasmic sperm injection in a patient exhibiting persistent oocyte macro vacuolization—Case report

To describe a case of homogeneous macro vacuolar formation in oocytes from a patient undergoing IVF/ICSI over 3 cycles and implications thereof. Case report and analysis of cycle outcomes including spindle visualization to determine severity of internal disruption caused. Characteristic macro vacuoles (>25 microm diameter) were identified in the vast majority of oocytes. Spindle visualization identified that macro vacuoles were not associated with spindle displacement. IVF resulted in failed fertilization. Low numbers of fertilized oocytes were obtained through ICSI. The vast majority of embryos exhibited maturation arrest on day 2. It is likely that persistent Oocyte Macro Vacuolization is the cause of infertility in this patient. It probably has a biological basis and possibly a genetic cause, resulting in either uncontrollable endocytosis or poor exocytosis and consequent vacuolar formation.

Intradiscal electrothermal therapy for symptomatic internal disc disruption: 24-month results and predictors of clinical success

Degeneration of the intervertebral disc can be the source of severe low-back pain. Intradiscal electrothermal therapy (IDET) is a minimally invasive treatment option for patients with symptomatic internal disc disruption unresponsive to conservative medical care. This study was undertaken in the neurosurgical setting to evaluate 24-month pain and functional outcomes and predictors of clinical success in patients with discogenic back pain treated with IDET. Using MR imaging and discography findings, 50 patients with lumbar discogenic pain were identified, underwent IDET treatment, and were followed up for 24 months. Outcomes included assessments of back pain severity based on an 11-point numeric scale and back function based on the Oswestry Disability Index. The Prolo scale was applied to determine economic and functional status at 24 months. There was an average 68 and 66% improvement in back pain and function, respectively, between pretreatment and 24 months after treatment (p < 0.0001 for both comparisons). A maximum score of 5 on the Prolo scale for economic and functional status was achieved in 63 and 22% of patients, respectively. The global clinical success rate was 78% (39 of 50 patients) based on no reoperations at the affected level due to persistent symptoms, with a >or= 2-point improvement in pain severity and a >or= 15-point improvement in back function. Predictors of 24-month clinical success included discographic concordance (p < 0.0001), a high-intensity zone on MR imaging (p = 0.0003), low Pfirrmann grade (p = 0.0002), and more extensive anulus coverage (p < 0.0001). There were no procedure-related adverse events. The findings of this study suggest that durable clinical improvements can be realized after IDET in highly select surgical candidates with mild disc degeneration, confirmatory imaging evidence of anular disruption, and highly concordant pain provocation on low-pressure discography.

Toxicity and bioaccumulation of the booster biocide copper pyrithione, copper 2-pyridinethiol-1-oxide, in gill tissues of Salvelinus fontinalis (brook trout)

This investigation studied the acute effects of copper pyrithione (CuPT) exposure on juvenile brook trout, Salvelinus fontinalis. Morphologic changes, copper bioaccumulation, and markers of oxidative stress in gill tissue were studied. Juvenile brook trout were treated with one of six experimental doses of CuPT (2-64 microg/L) for 2 hours. A seventh group served as a control population. Inductively coupled plasma atomic absorbance spectrophotometry (ICPAAS) analysis demonstrates significantly increased levels of copper in gill tissue (p < 0.001). Results from scanning electron microscopy and histological analysis demonstrate the formation of club-shaped lamella, edema, fusion of secondary lamella, loss of microridge structures and epithelial exfoliation. Transmission electron microscopy revealed altered morphology of chloride cells, including the swollen appearance of mitochondria with disruption of internal cristae and lipid membrane disruption. Thiobarbituric acid reactive substance (TBARS) assays demonstrated increased levels of lipid peroxidation products in gill tissue. Assays for the total antioxidant capacity of gill tissue revealed significantly lowered antioxidant levels. This data indicates that CuPT is potentially harmful to nontarget aquatic organisms at environmentally relevant doses.

Seymour Martin Lipset and political sociology1

Seymour Martin Lipset and political sociology¹