Endotoxins and disease mechanisms

In this chapter, current concepts about the mechanisms of action of endotoxin are reviewed. Particular attention is focused upon endotoxin-induced production of soluble mediators from macrophages and mononuclear cells and on the potential contribution of these mediators to endotoxin shock. In many cases, the interrelationships between these mediators as primary and/or secondary consequences of endotoxin stimulation of mononuclear phagocytes are discussed. Final comments address the relevance of these mediators to the therapy of endotoxin shock.

Sample design and cohort selection in the Hispanic Community Health Study/Study of Latinos

PURPOSE

The Hispanic Community Health Study (HCHS)/Study of Latinos (SOL) is a multicenter, community-based cohort study of Hispanic/Latino adults in the United States. A diverse participant sample is required that is both representative of the target population and likely to remain engaged throughout follow-up. The choice of sample design, its rationale, and benefits and challenges of design decisions are described in this study.

METHODS

The study design calls for recruitment and follow-up of a cohort of 16,000 Hispanics/Latinos 18-74 years of age, with 62.5% (10,000) over 44 years of age and adequate subgroup sample sizes to support inference by Hispanic/Latino background. Participants are recruited in community areas surrounding four field centers in the Bronx, Chicago, Miami, and San Diego. A two-stage area probability sample of households is selected with stratification and oversampling incorporated at each stage to provide a broadly diverse sample, offer efficiencies in field operations, and ensure that the target age distribution is obtained.

CONCLUSIONS

Embedding probability sampling within this traditional, multisite cohort study design enables competing research objectives to be met. However, the use of probability sampling requires developing solutions to some unique challenges in both sample selection and recruitment, as described here.

The incidence and prevalence of ankle sprain injury: a systematic review and meta-analysis of prospective epidemiological studies

BACKGROUND

Ankle sprain is one of the most common musculoskeletal injuries, yet a contemporary review and meta-analysis of prospective epidemiological studies investigating ankle sprain does not exist.

OBJECTIVE

Our aim is to provide an up-to-date account of the incidence rate and prevalence period of ankle sprain injury unlimited by timeframe or context activity.

METHODS

We conducted a systematic review and meta-analyses of English articles using relevant computerised databases. Search terms included Medical Search Headings for the ankle joint, injury and epidemiology. The following inclusion criteria were used: the study must report epidemiology findings of injuries sustained in an observed sample; the study must report ankle sprain injury with either incidence rate or prevalence period among the surveyed sample, or provide sufficient data from which these figures could be calculated; the study design must be prospective. Independent extraction of articles was performed by two authors using pre-determined data fields.

RESULTS

One-hundred and eighty-one prospective epidemiology studies from 144 separate papers were included. The average rating of all the included studies was 6.67/11, based on an adapted version of the STROBE (STrengthening the Reporting of OBservational studies in Epidemiology) guidelines for rating observational studies. 116 studies were considered high quality and 65 were considered low quality. The main findings of the meta-analysis demonstrated a higher incidence of ankle sprain in females compared with males (13.6 vs 6.94 per 1,000 exposures), in children compared with adolescents (2.85 vs 1.94 per 1,000 exposures) and adolescents compared with adults (1.94 vs 0.72 per 1,000 exposures). The sport category with the highest incidence of ankle sprain was indoor/court sports, with a cumulative incidence rate of 7 per 1,000 exposures or 1.37 per 1,000 athlete exposures and 4.9 per 1,000 h. Low-quality studies tended to underestimate the incidence of ankle sprain when compared with high-quality studies (0.54 vs 11.55 per 1,000 exposures). Ankle sprain prevalence period estimates were similar across sub-groups. Lateral ankle sprain was the most commonly observed type of ankle sprain.

CONCLUSIONS

Females were at a higher risk of sustaining an ankle sprain compared with males and children compared with adolescents and adults, with indoor and court sports the highest risk activity. Studies at a greater risk of bias were more likely to underestimate the risk of ankle sprain. Participants were at a significantly higher risk of sustaining a lateral ankle sprain compared with syndesmotic and medial ankle sprains.

Recovery From a First-Time Lateral Ankle Sprain and the Predictors of Chronic Ankle Instability: A Prospective Cohort Analysis

BACKGROUND

Impairments in motor control may predicate the paradigm of chronic ankle instability (CAI) that can develop in the year after an acute lateral ankle sprain (LAS) injury. No prospective analysis is currently available identifying the mechanisms by which these impairments develop and contribute to long-term outcome after LAS.

PURPOSE

To identify the motor control deficits predicating CAI outcome after a first-time LAS injury.

STUDY DESIGN

Cohort study (diagnosis); Level of evidence, 2.

METHODS

Eighty-two individuals were recruited after sustaining a first-time LAS injury. Several biomechanical analyses were performed for these individuals, who completed 5 movement tasks at 3 time points: (1) 2 weeks, (2) 6 months, and (3) 12 months after LAS occurrence. A logistic regression analysis of several "salient" biomechanical parameters identified from the movement tasks, in addition to scores from the Cumberland Ankle Instability Tool and the Foot and Ankle Ability Measure (FAAM) recorded at the 2-week and 6-month time points, were used as predictors of 12-month outcome.

RESULTS

At the 2-week time point, an inability to complete 2 of the movement tasks (a single-leg drop landing and a drop vertical jump) was predictive of CAI outcome and correctly classified 67.6% of cases (sensitivity, 83%; specificity, 55%; P = .004). At the 6-month time point, several deficits exhibited by the CAI group during 1 of the movement tasks (reach distances and sagittal plane joint positions at the hip, knee and ankle during the posterior reach directions of the Star Excursion Balance Test) and their scores on the activities of daily living subscale of the FAAM were predictive of outcome and correctly classified 84.8% of cases (sensitivity, 75%; specificity, 91%; P < .001).

CONCLUSION

An inability to complete jumping and landing tasks within 2 weeks of a first-time LAS and poorer dynamic postural control and lower self-reported function 6 months after a first-time LAS were predictive of eventual CAI outcome.

From anchovies to sardines and back: multidecadal change in the Pacific Ocean

In the Pacific Ocean, air and ocean temperatures, atmospheric carbon dioxide, landings of anchovies and sardines, and the productivity of coastal and open ocean ecosystems have varied over periods of about 50 years. In the mid-1970s, the Pacific changed from a cool "anchovy regime" to a warm "sardine regime." A shift back to an anchovy regime occurred in the middle to late 1990s. These large-scale, naturally occurring variations must be taken into account when considering human-induced climate change and the management of ocean living resources.

Hippocampal system and declarative (relational) memory: summarizing the data from functional neuroimaging studies

In the last several years there have been impressive strides in the ability to explore the nature of hippocampal system functioning in humans by employing functional neuroimaging methods, permitting such methods to be used in conjunction with neuropsychological methods to better understand the role of the hippocampal system in memory. In this paper, we review the literature on functional imaging studies of the hippocampal system, summarizing the data and testing these data against a number of theories or explanatory accounts of hippocampal function. We consider five alternative explanatory accounts of, or ideas about, hippocampal function- some from already existing work, for which the functional imaging data can provide a new test, and others that have emerged directly from the functional imaging work, and that have yet to be tested for their fit of data from neuropsychological methods. We conclude that the relational (declarative) memory account, in which it is proposed that the hippocampal system plays a critical role in binding together multiple inputs to permit representations of the relations among the constituent elements of scenes or events, can better accommodate the full range of imaging (and other existing) data than any other explanatory account of hippocampal function.

The efficacy of a semirigid ankle stabilizer to reduce acute ankle injuries in basketball. A randomized clinical study at West Point

This randomized clinical study was designed to prospectively determine the efficacy of a semirigid ankle stabilizer in reducing the frequency and severity of acute ankle injuries in basketball. Athletic shoe, playing surface, athlete-exposure, ankle injury history, and brace assignment were either statistically or experimentally controlled. Participants in the study were 1601 United States Military Academy cadets with no preparticipation, clinical, functional, or radiographic evidence of ankle instability. Subjects experienced a total of 13,430 athlete-exposures in the 1990 and 1991 intramural basketball seasons. Ankle injury was defined as acute trauma to the ankle ligaments that resulted in an athlete's inability to participate in basketball 1 day after the injury. Use of ankle stabilizers significantly reduced the frequency of ankle injuries. Reduction in ankle injuries, however, depended on the nature of injury (fewer contact injuries occurred among those who wore braces). Injury severity was not statistically reduced, and wearing the ankle stabilizer did not affect the frequency of knee injuries. Attitude toward ankle stabilizer use improved as use of the stabilizer increased.

Tendon-healing to cortical bone compared with healing to a cancellous trough. A biomechanical and histological evaluation in goats

This study was performed to test the hypothesis that attaching a tendon to a trough in cancellous bone results in tendon-healing that is biomechanically superior to that after direct fixation of a tendon to cortical bone. Twenty adult female goats were treated with a bilateral tenotomy of the infraspinatus tendon with subsequent reattachment of the tendon. In shoulders randomized to the cancellous-fixation group, a cancellous bed was prepared with a motorized burr and a template measuring twenty by five by five millimeters. The repair in the shoulders randomized to the cortical-fixation group was performed in the same manner, except that the tendon was attached to cortical bone. Three outcome measures were assessed, six and twelve weeks after the repair, with the Student paired t test and analysis of variance: load to failure, energy to failure, and stiffness. The types of repair were not significantly different with regard to any of the three outcomes. When the six and twelve-week data were combined, an average difference in load to failure of 3.9 per cent in favor of cancellous repair was observed but it was not significant (p = 0.78). The associated 95 per cent confidence interval for the difference ranged from 10.5 per cent in favor of cortical repair to 18.3 per cent in favor of cancellous repair. Histological analysis at six and twelve weeks revealed progressive maturation and reorganization of the bone-tendon interface with re-establishment of collagen-fiber continuity between the tendon and bone. This process was indistinguishable between the cortical and cancellous specimens. This study demonstrated no significant benefit from the creation of a trough to expose the tendon to cancellous bone. In this model, at both six and twelve weeks, the tendon-to-bone healing process of the two groups appeared similar and the biomechanical properties were approximately equal.

Dysregulated bioenergetics: a key regulator of joint inflammation

OBJECTIVES

This study examines the relationship between synovial hypoxia and cellular bioenergetics with synovial inflammation.

METHODS

Primary rheumatoid arthritis synovial fibroblasts (RASF) were cultured with hypoxia, dimethyloxalylglycine (DMOG) or metabolic intermediates. Mitochondrial respiration, mitochondrial DNA mutations, cell invasion, cytokines, glucose and lactate were quantified using specific functional assays. RASF metabolism was assessed by the XF24-Flux Analyzer. Mitochondrial structural morphology was assessed by transmission electron microscopy (TEM). In vivo synovial tissue oxygen (tpO2 mmHg) was measured in patients with inflammatory arthritis (n=42) at arthroscopy, and markers of glycolysis/oxidative phosphorylation (glyceraldehyde 3-phosphate dehydrogenase (GAPDH), PKM2, GLUT1, ATP) were quantified by immunohistology. A subgroup of patients underwent contiguous MRI and positron emission tomography (PET)/CT imaging. RASF and human dermal microvascular endothelial cells (HMVEC) migration/angiogenesis, transcriptional activation (HIF1α, pSTAT3, Notch1-IC) and cytokines were examined in the presence of glycolytic inhibitor 3-(3-Pyridinyl)-1-(4-pyridinyl)-2-propen-1-one (3PO).

RESULTS

DMOG significantly increased mtDNA mutations, mitochondrial membrane potential, mitochondrial mass, reactive oxygen species and glycolytic RASF activity with concomitant attenuation of mitochondrial respiration and ATP activity (all p<0.01). This was coupled with altered mitochondrial morphology. Hypoxia-induced lactate levels (p<0.01), which in turn induced basic fibroblast growth factor (bFGF) secretion and RASF invasiveness (all p<0.05). In vivo glycolytic markers were inversely associated with synovial tpO2 levels <20 mm Hg, in contrast ATP was significantly reduced (all p<0.05). Decrease in GAPDH and GLUT1 was paralleled by an increase in in vivo tpO2 in tumour necrosis factor alpha inhibitor (TNFi) responders. Novel PET/MRI hybrid imaging demonstrated close association between metabolic activity and inflammation. 3PO significantly inhibited RASF invasion/migration, angiogenic tube formation, secretion of proinflammatory mediators (all p<0.05), and activation of HIF1α, pSTAT3 and Notch-1IC under normoxic and hypoxic conditions.

CONCLUSIONS

Hypoxia alters cellular bioenergetics by inducing mitochondrial dysfunction and promoting a switch to glycolysis, supporting abnormal angiogenesis, cellular invasion and pannus formation.

Challenges in maintaining treatment services for people who use drugs during the COVID-19 pandemic

The impact of COVID-19 across health services, including treatment services for people who use drugs, is emerging but likely to have a high impact. Treatment services for people who use drugs provide essential treatment services including opiate agonist treatment and needle syringe programmes alongside other important treatment programmes across all substance types including withdrawal and counselling services. Drug and alcohol hospital consultation-liaison clinicians support emergency departments and other services provided in hospital settings in efficiently managing patients who use drugs and present with other health problems.COVID-19 will impact on staff availability for work due to illness. Patients may require home isolation and quarantine periods. Ensuring ongoing supply of opiate treatment during these periods will require significant changes to how treatment is provided. The use of monthly depot buprenorphine as well as moving from a framework of supervised dosing will be required for patients on sublingual buprenorphine and methadone. Ensuring ready access to take-home naloxone for patients is crucial to reduce overdose risks. Delivery of methadone and buprenorphine to the homes of people with confirmed COVID-19 infections is likely to need to occur to support home isolation.People who use drugs are likely to be more vulnerable during the COVID-19 epidemic, due to poorer health literacy and stigma and discrimination towards this group. People who use drugs may prioritise drug use above other health concerns. Adequate supply of clean injecting equipment is important to prevent outbreaks of blood-borne viruses. Opiate users may misinterpret SARS-CoV2 symptoms as opiate withdrawal and manage this by using opioids. Ensuring people who use drugs have access to drug treatment as well as access to screening and testing for SARS-CoV2 where this is indicated is important.

Vaccination of Glioma Patients with Fusions of Dendritic and Glioma Cells and Recombinant Human Interleukin 12

Despite aggressive treatment, the median survival of patients with high-grade malignant astrocytoma is about 1 year. The authors investigated the safety and clinical response to immunotherapy using fusions of dendritic and glioma cells combined with recombinant human interleukin 12 (rhIL-12) for the treatment of malignant glioma. Fifteen patients with malignant glioma participated in this study. Dendritic cells were generated from peripheral blood. Cultured autologous glioma cells were established from surgical specimens in each case. Fusion cells were prepared from dendritic and glioma cells using polyethylene glycol. All patients received fusion cells intradermally on day 1. rhIL-12 was injected subcutaneously at the same site on days 3 and 7. Response to the treatment was evaluated by clinical observations and radiologic findings. No serious adverse effects were observed. In four patients, magnetic resonance imaging showed a greater than 50% reduction in tumor size. One patient had a mixed response. These results show that administration of fusion cells and rhIL-12 safely induces clinical antitumor effects in some patients with malignant glioma.

Targeted mutagenesis of Smad1 reveals an essential role in chorioallantoic fusion

The Smad family of intracellular signaling intermediates transduce signals downstream from the transforming growth factor beta (TGF-beta) family of receptor serine threonine kinases. The original member of this family, Smad1, has been shown to mediate signals from receptors for the bone morphogenetic proteins (BMPs), a large group of ligands in the TGF-beta superfamily that mediate important developmental events. We have targeted the Smad1 gene in mice and created mutants null at this locus. Smad1 mutant mice die at approximately 9.5 days postcoitum due to defects in allantois formation. In Smad1 mutant mice, the allantois fails to fuse to the chorion, resulting in a lack of placenta and failure to establish a definitive embryonic circulation. Although vasculogenesis is initiated in the mutant allantois, the vessels formed are disorganized, and VCAM-1 protein, a marker for distal allantois development, is not expressed. Smad1 null fibroblasts are still able to respond to BMP2, however, suggesting that the defect observed in the developing extraembryonic tissue is caused by a very specific loss of transcriptional activity regulated by Smad1. Our data further demonstrate that although highly similar structurally, Smad proteins are not functionally homologous.

Improved survival with the use of adjuvant chemotherapy in the treatment of medulloblastoma

Between 1975 and 1989, 108 children with newly diagnosed medulloblastoma/primitive neuroectodermal tumor (MB/PNET) of the posterior fossa were treated at the authors' institution. The patients were managed uniformly, and treatment included aggressive surgical resections, postoperative staging evaluations for extent of disease, and craniospinal radiation therapy with a local boost. Beginning in 1983, children with MB/PNET were prospectively assigned to risk groups; those with "standard-risk" MB/PNET were treated with radiation therapy alone, while those in the "poor-risk" group received similar radiation therapy plus adjuvant chemotherapy with 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU), vincristine, and cisplatin. The 5-year actuarial disease-free survival rate for all patients treated between 1975 and 1982 was 68%, and 73% when patients who died within 2 weeks after operation were excluded. This survival rate was statistically better for patients treated after 1982 (82%) compared to those treated between 1975 and 1982 (49%) (p less than 0.004). There was no difference in disease-free survival rates over time for children with standard-risk factors; however, there was a significant difference in the 5-year survival rate for poor-risk patients treated prior to 1982 (35%) compared to those treated later (87%) (p less than 0.001). For the group as a whole, a younger age at diagnosis correlated with a poorer survival rate; however, this relationship between age and outcome was significant only for children treated before 1983 (p less than 0.001). These results demonstrated an encouraging survival rate for children with MB/PNET, especially those treated with aggressive surgical resection followed by both radiation therapy and chemotherapy. The results strongly suggest that chemotherapy has a role for some, and possibly all, children with MB/PNET.

Grouping and short-term memory: different means and patterns of grouping

Two experiments, concerned with the improving effects of grouping on auditory short-term memory, are described. In the first, temporal grouping was found to improve recall considerably, but non-temporal grouping had a much smaller effect. Temporal grouping reduced the order errors more than other errors; it also changed the pattern of the order errors. Further, it altered the shape of the serial position curve of all errors. In the second experiment, irregular patterns of temporal grouping were found to be inferior to a regular pattern. The results are discussed in terms of the time available for processing previous items during the presentation of a sequence, and the form that this processing may take.

Impact of a premature menopause on cognitive function in later life

OBJECTIVE

To determine whether premature menopause (≤40 years) can have long-lasting effects on later-life cognition and investigate whether this association varies depending on the type of menopause and use of hormone treatment (HT).

DESIGN

Population-based cohort study.

SETTING

The French Three-City Study.

POPULATION

Four thousand eight hundred and sixty-eight women aged at least 65 years.

METHODS

Multivariable-adjusted logistic regression models were used to determine the association between age at menopause, type of menopause (surgical, natural), and the use of menopausal HT and later-life cognitive function.

MAIN OUTCOME MEASURES

Performance on a cognitive test battery (at baseline and over 7 years) and clinical dementia diagnosis.

RESULTS

Menopause at or before the age of 40 years, both premature bilateral ovariectomy and premature ovarian failure (non-surgical loss of ovarian function), was associated with worse verbal fluency (OR 1.56, 95%CI 1.12-1.87, P=0.004) and visual memory (OR 1.39, 95%CI 1.09-1.77, P=0.007) in later life. HT at the time of premature menopause appeared beneficial for later-life visual memory but increased the risk of poor verbal fluency. Type of menopause was not significantly associated with cognitive function. Premature menopause was associated with a 30% increased risk of decline in psychomotor speed and global cognitive function over 7 years.

CONCLUSION

Both premature surgical menopause and premature ovarian failure were associated with long-term negative effects on cognitive function, which are not entirely offset by menopausal HT. In terms of surgical menopause, these results suggest that the potential long-term effects on cognitive function should form part of the risk/benefit ratio when considering ovariectomy in younger women.

Detection of a mediator derived from endotoxin-stimulated macrohpages that induces the acute phase serum amyloid A response in mice

The mechanism by which LPS stimulates an acute phase serum amyloid A (SAA) response in C3H mice has been studied. A factor (SAA inducer) appears in the blood of C3H/HeN (lipopolysaccharide [LPS]-sensitive) mice approximately 1 h after administration of LPS, which, when passively administered, can induce C3H/HeJ mice to produce SAA although they are resistant to the LPS itself. SAA inducer has been detected in the culture medium of LPS treated C3H/HeN macrophages but not spleen cells. Thus, two stages in the induction of the acute phase SAA response are now recognized: a latent period of 2-3 h during which the SAA concentration remains at baseline values and in which SAA inducer appears, and the period of synthesis of SAA which lasts for approoximately 24 h past induction. It is proposed that a macrophage response to LPS is responsible for production of the serum mediator which induces SAA synthesis.

Very-Long-Baseline Radio Interferometry: The Mark III System for Geodesy, Astrometry, and Aperture Synthesis

The Mark III very-long-baseline interferometry (VLBI) system allows recording and later processing of up to 112 megabits per second from each radio telescope of an interferometer array. For astrometric and geodetic measurements, signals from two radio-frequency bands (2.2 to 2.3 and 8.2 to 8.6 gigahertz) are sampled and recorded simultaneously at all antenna sites. From these dual-band recordings the relative group delays of signals arriving at each pair of sites can be corrected for the contributions due to the ionosphere. For many radio sources for which the signals are sufficiently intense, these group delays can be determined with uncertainties under 50 picoseconds. Relative positions of widely separated antennas and celestial coordinates of radio sources have been determined from such measurements with 1 standard deviation uncertainties of about 5 centimeters and 3 milliseconds of arc, respectively. Sample results are given for the lengths of baselines between three antennas in the United States and three in Europe as well as for the arc lengths between the positions of six extragalactic radio sources. There is no significant evidence of change in any of these quantities. For mapping the brightness distribution of such compact radio sources, signals of a given polarization, or of pairs of orthogonal polarizations, can be recorded in up to 28 contiguous bands each nearly 2 megahertz wide. The ability to record large bandwidths and to link together many large radio telescopes allows detection and study of compact sources with flux densities under 1 millijansky.

Hyalinizing trabecular adenoma of the thyroid gland

The hyalinizing trabecular adenoma, a distinctive lesion, is important because it may mimic medullary and papillary carcinoma microscopically. We describe 11 such tumors obtained from women ages 27-72 years (mean, 46 years). The initial pathologic diagnoses were carcinoma (five cases), adenoma (two cases), paraganglioma (one case), and "indeterminate" (three cases). None of the tumors recurred or metastasized (mean follow-up, 10 years). Grossly, the neoplasms measured 0.3-4 cm in diameter, and were yellow-tan and circumscribed. Microscopically, they were encapsulated or circumscribed and solid, or vaguely lobulated. The polygonal, oval, and elongated tumor cells were arranged in trabeculae, clusters, or both, and were often inserted vertically into capillaries. The sharply outlined cells had finely granular cytoplasm that was either acidophilic, amphophilic, or clear. Typical features included oval and elongated nuclei, perinucleolar vacuoles, acidophilic nuclear inclusions, fine nuclear grooving, and infrequent mitotic figures. Perivascular hyaline fibrosis and cell degeneration mimicked amyloid, but these tumors were Congo red-negative. Occasional trabeculae featured round or irregularly shaped follicles, sometimes with papillary infoldings, that were either empty or contained colloid-like material and psammoma bodies. Immunostaining of tumor cells was positive for thyroglobulin and negative for calcitonin. Among six tumors analyzed by flow cytometry, five displayed a diploid pattern and one showed an aneuploid peak.

A controlled trial of an educational program to prevent low back injuries

BACKGROUND

Low back injuries are common and costly, accounting for 15 to 25 percent of injuries covered by workers' compensation and 30 to 40 percent of the payments made under that program. The high costs of injury, the lack of effective treatment. and the evidence that there are behavioral risk factors have led to widespread use of employee education programs that teach safe lifting and handling. The effectiveness of those programs, however, has received little rigorous evaluation.

METHODS

We evaluated an educational program designed to prevent low back injury in a randomized, controlled trial involving about 4000 postal workers. The program, similar to that in wide use in so-called back schools, was taught by experienced physical therapists. Work units of workers and supervisors were trained in a two-session back school (three hours of training), followed by three to four reinforcement sessions over the succeeding few years. Injured subjects (from both the intervention and the control groups) were randomized a second time to receive either training or no training after their return to work.

RESULTS

Physical therapists trained 2534 postal workers and 134 supervisors. Over 5.5 years of follow-up, 360 workers reported low back injuries, for a rate of 21.2 injuries per 1000 worker-years of risk. The median time off from work per injury was 14 days (range, 0 to 1717); the median cost was $204 (range, zero to $190,380). After their return to work, 75 workers were injured again. Our comparison of the intervention and control groups found that the education program did not reduce the rate of low back injury, the median cost per injury, the time off from work per injury, the rate of related musculoskeletal injuries, or the rate of repeated injury after return to work; only the subjects' knowledge of safe behavior was increased by the training.

CONCLUSIONS

A large-scale, randomized, controlled trial of an educational program to prevent work-associated low back injury found no long-term benefits associated with training.

Phase III comparison of doxorubicin and dacarbazine given by bolus versus infusion in patients with soft-tissue sarcomas: a Southwest Oncology Group study

Disseminated soft-tissue sarcomas are a group of uncommon malignancies generally treated in a uniform manner. This study questioned the impact of schedule on response rate and toxicity in patients with metastatic soft-tissue sarcoma treated with the two-drug combination doxorubicin and dacarbazine. Patients were randomly assigned to receive either bolus therapy with doxorubicin at a dose of 60 mg/m2 and dacarbazine at a dose of 750 mg/m2 intravenously on day 1 (118 patients) or infusional therapy with doxorubicin at 60 mg/m2 and dacarbazine at 750 mg/m2 delivered by continuous intravenous infusion for 96 hours on days 1-4 (122 patients). Chemotherapy was to be repeated every 3 weeks. A unique feature of this cooperative group protocol was a provision for surgical resection of residual disease in patients with a partial response or with stable disease following chemotherapy. Similar overall response rates (17% in both treatment arms) and complete response rates (5% in both treatment arms) were observed. For patients receiving bolus therapy, the median response duration was 19.6 months for those in complete remission and 6.6 months for those in partial remission. For patients receiving infusional therapy, the median response duration was 12.6 months for those in complete remission and 9.3 months for those in partial remission. Examination of dose intensity received when combining treatment arms revealed a weak doxorubicin dose-response relationship. There was no difference in median survival times between the two treatment arms (bolus therapy, 10.6 months; infusional therapy, 10.5 months; logrank P = .97). Analysis of toxic effects favored infusional therapy. Significant reductions in cardiac toxicity (all events, P = .04; clinical events, P = .01) and nausea and emesis (P = .04) were seen in infusional therapy. Of 47 patients eligible for cytoreductive surgery following chemotherapy, 12 received surgery, and of those 12, eight were rendered disease free. The use of a 96-hour continuous intravenous infusion of doxorubicin-dacarbazine was comparable therapeutically with bolus dosing of these two agents and was better tolerated by the patients.

Mitochondrial dynamics in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is an idiopathic cardiopulmonary disease characterized by obstruction of small pulmonary arteries. Vascular obstruction is the consequence of excessive proliferation and apoptosis resistance of vascular cells, as well as inflammation, thrombosis, and vasoconstriction. Vascular obstruction increases the afterload faced by the right ventricle (RV), leading to RV failure. The proliferative, obstructive vasculopathy of PAH shares several mitochondrial abnormalities with cancer, notably a shift to aerobic glycolysis and mitochondrial fragmentation. Mitochondria in the pulmonary artery smooth muscle cell (PASMC) normally serve as oxygen sensors. In PAH, acquired mitochondrial abnormalities, including epigenetic silencing of superoxide dismutase (SOD2), disrupt oxygen sensing creating a pseudo-hypoxic environment characterized by normoxic activation of hypoxia-inducible factor-1α (HIF-1α). The resulting metabolic shift to aerobic glycolysis (the Warburg phenomenon) reflects inhibition of pyruvate dehydrogenase by pyruvate dehydrogenase kinases. In addition, altered mitochondrial dynamics result in mitochondrial fragmentation. The molecular basis of this structural change includes upregulation and activation of fission mediators, notably dynamin-related protein 1 (DRP-1), and downregulation of fusion mediators, especially mitofusin-2 (MFN2). These pathogenic mitochondrial abnormalities offer new therapeutic targets. Inhibition of mitotic fission or enhancement of fusion in PAH PASMC slows cell proliferation, causes cell cycle arrest, and induces apoptosis. DRP-1 inhibition or MFN2 gene therapy can regress PAH in experimental models of PAH. This review focuses on the etiology of mitochondrial fragmentation in PAH and explores the therapeutic implications of mitochondrial dynamics in the pulmonary vasculature and RV.