Multi-Institutional Patterns of Use of Tumor-Treating Fields for Patients with Malignant Pleural Mesothelioma

(1) Background: The objective of this analysis was to evaluate the device usage rates and patterns of use regarding Tumor-Treating Fields (TTFields) for patients with malignant pleural mesothelioma (MPM) throughout the US. (2) Methods: We evaluated de-identified data from 33 patients with MPM enrolled in FDA-required HDE protocols at 14 institutions across the US from September 2019 to March 2022. (3) Results: The median number of total TTFields usage days was 72 (range: 6-649 days), and the total treatment duration was 160 months for all patients. A low usage rate (defined as less than 6 h per day, 25%) was observed in 34 (21.2%) months. The median TTFields usage in the first 3 months was 12 h per day (range: 1.9-21.6 h), representing 50% (range: 8-90%) of the potential daily duration. The median TTFields usage after 3 months decreased to 9.1 h per day (range: 3.1-17 h), representing 38% (range: 13-71%) of the daily duration, and was lower than usage in the first 3 months (p = 0.01). (4) Conclusions: This study represents the first multicenter analysis of real-world TTFields usage based on usage patterns for MPM patients in clinical practice. The real-world usage level was lower than the suggested daily usage. Further initiatives and guidelines should be developed to evaluate the impact of this finding on tumor control.

Isogenic Mammary Models of Intraductal Carcinoma Reveal Progression to Invasiveness in the Absence of a Non-Obligatory In Situ Stage

In breast cancer, progression to invasive ductal carcinoma (IDC) involves interactions between immune, myoepithelial, and tumor cells. Development of IDC can proceed through ductal carcinoma in situ (DCIS), a non-obligate, non-invasive stage, or IDC can develop without evidence of DCIS and these cases associate with poorer prognosis. Tractable, immune-competent mouse models are needed to help delineate distinct mechanisms of local tumor cell invasion and prognostic implications. To address these gaps, we delivered murine mammary carcinoma cell lines directly into the main mammary lactiferous duct of immune-competent mice. Using two strains of immune-competent mice (BALB/c, C57BL/6), one immune-compromised (severe combined immunodeficiency; SCID) C57BL/6 strain, and six different murine mammary cancer cell lines (D2.OR, D2A1, 4T1, EMT6, EO771, Py230), we found early loss of ductal myoepithelial cell differentiation markers p63, α-smooth muscle actin, and calponin, and rapid formation of IDC in the absence of DCIS. Rapid IDC formation also occurred in the absence of adaptive immunity. Combined, these studies demonstrate that loss of myoepithelial barrier function does not require an intact immune system, and suggest that these isogenic murine models may prove a useful tool to study IDC in the absence of a non-obligatory DCIS stage-an under-investigated subset of poor prognostic human breast cancer.

Angiotensin receptor blockade and stereotactic body radiation therapy for early stage lung cancer ARB & SBRT for early stage lung cancer

Stereotactic body radiotherapy (SBRT) demonstrates excellent local control in early stage lung cancer, however a quarter of patients develop recurrence or distant metastasis. Transforming growth factor-beta (TGF-β) supports metastasis and treatment resistance, and angiotensin receptor blockade (ARB) indirectly suppresses TGF-β signaling. This study investigates whether patients taking ARBs while undergoing SBRT for early stage lung cancer exhibited improved overall survival (OS) or recurrence free survival (RFS) compared to patients not taking ARBs. This was a single institution retrospective analysis of 272 patients treated with SBRT for early stage lung cancer between 2009 and 2018. Patient health data was abstracted from the electronic medical record. OS and RFS were assessed using Kaplan-Meier method. Log-rank test was used to compare unadjusted survival between groups. Univariable and multivariable Cox proportional hazard regression models were used to estimate hazard ratios (HRs). Of 247 patients analyzed, 24 (10%) patients took ARBs for the duration of radiotherapy. There was no difference in mean age, median tumor diameter, or median biologic effective dose between patients taking ARBs or not. Patients taking ARBs exhibited increased OS (ARB = 96.7 mo.; no ARB = 43.3 mo.; HR = 0.25 [95% CI: 0.10 to 0.62, P = .003]) and increased RFS (median RFS, ARB = 64.3 mo.; No ARB = 35.1 mo.; HR = 0.26 [95% CI: 0.10 to 0.63, P = .003]). These effects were not seen in patients taking angiotensin converting enzyme inhibitors (ACEIs) or statins. ARB use while undergoing SBRT for early stage lung cancer may increase OS and RFS, but ACEI use does not show the same effect.

Radiotherapy reimagined: Integrating nanomedicines into radiotherapy clinical trials

Radioenhancing nanoparticles (NPs) are being evaluated in ongoing clinical trials for various cancers including head and neck, lung, esophagus, pancreas, prostate, and soft tissue sarcoma. Supported by decades of preclinical investigation and recent randomized trial data establishing clinical activity, these agents are poised to influence future multimodality treatment paradigms involving radiotherapy. Although the physical interactions between NPs and ionizing radiation are well characterized, less is known about how these agents modify the tumor microenvironment, particularly regarding tumor immunogenicity. In this review, we describe the key multidisciplinary considerations related to radiation, surgery, immunology, and pathology for designing radioenhancing NP clinical trials. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Remote ischaemic conditioning: defining critical criteria for success-report from the 11th Hatter Cardiovascular Workshop

The Hatter Cardiovascular Institute biennial workshop, originally scheduled for April 2020 but postponed for 2 years due to the Covid pandemic, was organised to debate and discuss the future of Remote Ischaemic Conditioning (RIC). This evolved from the large multicentre CONDI-2-ERIC-PPCI outcome study which demonstrated no additional benefit when using RIC in the setting of ST-elevation myocardial infarction (STEMI). The workshop discussed how conditioning has led to a significant and fundamental understanding of the mechanisms preventing cell death following ischaemia and reperfusion, and the key target cyto-protective pathways recruited by protective interventions, such as RIC. However, the obvious need to translate this protection to the clinical setting has not materialised largely due to the disconnect between preclinical and clinical studies. Discussion points included how to adapt preclinical animal studies to mirror the patient presenting with an acute myocardial infarction, as well as how to refine patient selection in clinical studies to account for co-morbidities and ongoing therapy. These latter scenarios can modify cytoprotective signalling and need to be taken into account to allow for a more robust outcome when powered appropriately. The workshop also discussed the potential for RIC in other disease settings including ischaemic stroke, cardio-oncology and COVID-19. The workshop, therefore, put forward specific classifications which could help identify so-called responders vs. non-responders in both the preclinical and clinical settings.

Resolvin D2 promotes host defense in a 2 - hit model of sepsis with secondary lung infection

In the development of sepsis, there is early, massive inflammation which can lead to multiple organ failure. Later there is an immunosuppressed phase where the host is susceptible to secondary infections or is unable to clear existing infection. Specialized Pro-resolving Mediators (SPMs) are endogenously produced lipids which resolve infection by decreasing bacteria load and reducing systemic inflammatory response. There has been little work studying if SPMs given late, can promote host defense. We examined if an SPM, Resolvin D2 (RvD2) could promote host defense in a 2-hit mouse model of cecal ligation and puncture (CLP) sepsis and secondary Pseudomonas aeruginosa lung infection. RvD2 given 48 h after mild CLP (1st hit), increased gene expression of Toll-like receptor-2 (TLR-2) and alveolar macrophage/monocyte phagocytic ability compared to CLP mice given saline vehicle. In this model, RvD2 did not affect plasma IL-6 or IL-10. These effects induced by RvD2, lowered lung bacterial load and decreased mortality after the secondary infection of Pseudomonas aeruginosa (2nd hit). Splenic T-cell numbers were also increased in RvD2 treated mice compared to saline vehicle treated animals. The results suggest that RvD2 promoted mechanisms of host defense in a 2-hit model sepsis and secondary lung infection.

Radiation enhances the delivery of antisense oligonucleotides and improves chemo-radiation efficacy in brain tumor xenografts

Overexpression of O⁶-methylguanine DNA methyltransferase (MGMT) contributes to resistance to chemo-radiation therapy (CRT) in brain tumors. We previously demonstrated that non-ablative radiation improved delivery of anti-MGMT morpholino oligonucleotides (AMONs) to reduce MGMT levels in subcutaneous tumor xenografts. We evaluate this approach to enhance CRT efficacy in rat brain tumor xenograft models. The impact of radiation on targeted delivery was evaluated using fluorescent oligonucleotides (f-ON). In vitro, f-ON was localized to clathrin-coated vesicles, endosomes, and lysosomes using confocal microscopy in T98G glioma cells. In vivo, fluorescence was detected in pre-radiated, but not non-radiated Long Evans (non-tumor bearing) rat brains. Cranial radiation (2 Gy) followed by AMONs (intravenous, 10.5 mg/kg) reduced MGMT expression by 50% in both orthotopic cerebellar D283 medulloblastoma and intracerebral H460 non-small cell lung carcinoma (NSCLC) xenograft models. To evaluate the efficacy, AMONs concurrent with CRT (2 Gy radiation plus oral 20 mg/kg temozolomide ×4 days) reduced tumor volumes in the medulloblastoma model (p = 0.012), and a similar trend was found in the NSCLC brain metastasis model. We provide proof of concept for the use of non-ablative radiation to guide and enhance the delivery of morpholino oligonucleotides into brain tumor xenograft models to reduce MGMT levels and improve CRT efficacy.

Exploiting Phagocytic Checkpoints in Nanomedicine: Applications in Imaging and Combination Therapies

Recent interest in cancer immunotherapy has largely been focused on the adaptive immune system, particularly adoptive T-cell therapy and immune checkpoint blockade (ICB). Despite improvements in overall survival and progression-free survival across multiple cancer types, neither cell-based therapies nor ICB results in durable disease control in the majority of patients. A critical component of antitumor immunity is the mononuclear phagocyte system and its role in both innate and adaptive immunity. The phagocytic functions of these cells have been shown to be modulated through multiple pathways, including the CD47-SIRPα axis, which is manipulated by cancer cells for immune evasion. In addition to CD47, tumors express a variety of other “don’t eat me” signals, including beta-2-microglobulin and CD24, and “eat me” signals, including calreticulin and phosphatidylserine. Therapies targeting these signals can lead to increased phagocytosis of cancer cells; however, because “don’t eat me” signals are markers of “self” on normal cells, treatment can result in negative off-target effects, such as anemia and B-cell depletion. Recent preclinical research has demonstrated the potential of nanocarriers to synergize with prophagocytic therapies, address the off-target effects, improve pharmacokinetics, and codeliver chemotherapeutics. The high surface area-to-volume ratio of nanoparticles paired with preferential size for passive targeting allows for greater accumulation of therapeutic cargo. In addition, nanomaterials hold promise as molecular imaging agents for the detection of phagocytic markers. This mini review highlights the unique capabilities of nanotechnology to expand the application and efficacy of immunotherapy through recently discovered phagocytotic checkpoint therapies.

NKTR-214 immunotherapy synergizes with radiotherapy to stimulate systemic CD8+ T cell responses capable of curing multi-focal cancer

Background

High-dose radiotherapy (RT) is known to be immunogenic, but is rarely capable of driving clinically relevant abscopal antitumor immunity as monotherapy. RT is known to increase antigen presentation, type I/II interferon responses, and immune cell trafficking to irradiated tumors. Bempegaldesleukin (NKTR-214) is a CD122-preferential interleukin 2 (IL-2) pathway agonist that has been shown to increase tumor-infiltrating lymphocytes, T cell clonality, and increase PD-1 expression. NKTR-214 has increased drug half-life, decreased toxicity, and increased CD8⁺ T cell and natural killer cell stimulation compared with IL-2.

Methods

Animals bearing bilateral subcutaneous MCA-205 fibrosarcoma or CT26 colorectal tumors were treated with NKTR-214, RT, or combination therapy, and tumor growth of irradiated and abscopal lesions was assessed. Focal RT was delivered using a small animal radiation research platform. Peripheral and tumor-infiltrating immune phenotype and functional analyses were performed by flow cytometry. RNA expression profiling from both irradiated and abscopal lesions was performed using microarray.

Results

We demonstrate synergy between RT of a single tumor and NKTR-214 systemic therapy resulting in dramatically increased cure rates of mice bearing bilateral tumors compared with RT or NKTR-214 therapy alone. Combination therapy resulted in increased magnitude and effector function of tumor-specific CD8⁺ T cell responses and increased trafficking of these T cells to both irradiated and distant, unirradiated, tumors.

Conclusions

Given the increasing role of hypofractionated and stereotactic body RT as standard of care treatments in the management of locally advanced and metastatic cancer, these data have important implications for future clinical trial development. The combination of RT and NKTR-214 therapy potently stimulates systemic antitumor immunity and should be evaluated for the treatment of patients with locally advanced and metastatic solid tumors.

Lipoxin A4 promotes reduction and antibiotic efficacy against Pseudomonas aeruginosa biofilm

Pseudomonas aeruginosa (P. aeruginosa) is an opportunistic bacterium commonly found in wound infections and airways of cystic fibrosis patients. P. aeruginosa readily forms biofilms which can reduce the efficacy of antibiotics used to eradicate the pathogen. We have previously shown that a Specialized Pro-resolving Mediator (SPM), Lipoxin A4 (LxA₄) is a quorum sensing inhibitor which can reduce P. aeruginosa virulence. In this study, we examined the direct actions of LxA₄ and RvD₂ on P. aeruginosa biofilm formation and virulence gene expression. The influence of LxA₄ on antibiotic efficacy and the combined effects on biofilm formation were also investigated. LxA₄ and RvD₂ reduced P. aeruginosa biofilm formation and virulence gene expression. LxA₄ increased ciprofloxacin inhibition on biofilm formation but did not affect ciprofloxacin's action on non-adherent bacteria. On the other hand, LxA₄ increased bacterial killing action of imipenem but did not affect imipenem's action on biofilm. We also found that LxA₄ can increase ciprofloxacin's bacterial killing ability in established biofilm. Together these results suggest that LxA₄ has direct effects on P. aeruginosa biofilm formation and can increase antibiotic efficacy directly.

Incorporating Radiation Oncology into Immunotherapy: proceedings from the ASTRO-SITC-NCI immunotherapy workshop

Radiotherapy (RT) has been a fundamental component of the anti-cancer armamentarium for over a century. Approximately half of all cancer patients are treated with radiotherapy during their disease course. Over the two past decades, there has been a growing body of preclinical evidence supporting the immunomodulatory effects of radiotherapy, particularly when combined with immunotherapy, but only anecdotal clinical examples existed until recently. The renaissance of immunotherapy and the recent U.S. Food and Drug Administration (FDA) approval of several immune checkpoint inhibitors (ICIs) and other immuno-oncology (IO) agents in multiple cancers provides the opportunity to investigate how localized radiotherapy can induce systemic immune responses. Early clinical experiences have demonstrated feasibility of this approach but additional preclinical and clinical investigation is needed to understand how RT and immunotherapy can be optimally combined.

To address questions that are critical to successful incorporation of radiation oncology into immunotherapy, the American Society for Radiation Oncology (ASTRO), the Society for Immunotherapy of Cancer (SITC) and the National Cancer Institute (NCI) organized a collaborative scientific workshop, Incorporating Radiation Oncology into Immunotherapy, that convened on June 15 and 16 of 2017 at the Natcher Building, NIH Campus in Bethesda, Maryland. This report summarizes key data and highlights from each session.

Multi-institutional experience of stereotactic body radiotherapy for large (≥5 centimeters) non-small cell lung tumors

BACKGROUND

Stereotactic body radiotherapy (SBRT) is the standard of care for patients with nonoperative, early-stage non-small cell lung cancer (NSCLC) measuring < 5 cm, but its use among patients with tumors measuring ≥5 cm is considerably less defined, with the existing literature limited to small, single-institution reports. The current multi-institutional study reported outcomes evaluating the largest such population reported to date.

METHODS

Clinical/treatment characteristics, outcomes, toxicities, and patterns of failure were assessed in patients with primary NSCLC measuring ≥5 cm without evidence of distant/lymph node metastasis who underwent SBRT using ≤5 fractions. Statistics included Kaplan-Meier survival analyses and univariate/multivariate Cox proportional hazards models.

RESULTS

A total of 92 patients treated from 2004 through 2016 were analyzed from 12 institutions. The median follow-up was 12 months (15 months in survivors). The median age and tumor size among the patients were 73 years (range, 50-95 years) and 5.4 cm (range, 5.0-7.5 cm), respectively. The median dose/fractionation was 50 Gray/5 fractions. The actuarial local control rates at 1 year and 2 years were 95.7% and 73.2%, respectively. The disease-free survival rate was 72.1% and 53.5%, respectively, at 1 year and 2 years. The 1-year and 2-year disease-specific survival rates were 95.5% and 78.6%, respectively. The median, 1-year, and 2-year overall survival rates were 21.4 months, 76.2%, and 46.4%, respectively. On multivariate analysis, lung cancer history and pre-SBRT positron emission tomography maximum standardized uptake value were found to be associated with overall survival. Posttreatment failures were most commonly distant (33% of all disease recurrences), followed by local (26%) and those occurring elsewhere in the lung (23%). Three patients had isolated local failures. Grade 3 to 4 toxicities included 1 case (1%) and 4 cases (4%) of grade 3 dermatitis and radiation pneumonitis, respectively (toxicities were graded according to the Common Terminology Criteria for Adverse Events [version 4.0]). Grades 2 to 5 radiation pneumonitis occurred in 11% of patients. One patient with a tumor measuring 7.5 cm and a smoking history of 150 pack-years died of radiation pneumonitis.

CONCLUSIONS

The results of the current study, which is the largest study of patients with NSCLC measuring ≥5 cm reported to date, indicate that SBRT is a safe and efficacious option. Cancer 2017;123:688-696. © 2016 American Cancer Society.

Multi-Institutional Experience of Stereotactic Ablative Radiation Therapy for Stage I Small Cell Lung Cancer

PURPOSE

For inoperable stage I (T1-T2N0) small cell lung cancer (SCLC), national guidelines recommend chemotherapy with or without conventionally fractionated radiation therapy. The present multi-institutional cohort study investigated the role of stereotactic ablative radiation therapy (SABR) for this population.

METHODS AND MATERIALS

The clinical and treatment characteristics, toxicities, outcomes, and patterns of failure were assessed in patients with histologically confirmed stage T1-T2N0M0 SCLC. Kaplan-Meier analysis was used to evaluate the survival outcomes. Univariate and multivariate analyses identified predictors of outcomes.

RESULTS

From 24 institutions, 76 lesions were treated in 74 patients (median follow-up 18 months). The median age and tumor size was 72 years and 2.5 cm, respectively. Chemotherapy and prophylactic cranial irradiation were delivered in 56% and 23% of cases, respectively. The median SABR dose and fractionation was 50 Gy and 5 fractions. The 1- and 3-year local control rate was 97.4% and 96.1%, respectively. The median disease-free survival (DFS) duration was 49.7 months. The DFS rate was 58.3% and 53.2% at 1 and 3 years, respectively. The median, 1-year, and 3-year disease-specific survival was 52.3 months, 84.5%, and 64.4%, respectively. The median, 1-year, and 3-year overall survival (OS) was 17.8 months, 69.9%, and 34.0% respectively. Patients receiving chemotherapy experienced an increased median DFS (61.3 vs 9.0 months; P=.02) and OS (31.4 vs 14.3 months; P=.02). The receipt of chemotherapy independently predicted better outcomes for DFS/OS on multivariate analysis (P=.01). Toxicities were uncommon; 5.2% experienced grade ≥2 pneumonitis. Post-treatment failure was most commonly distant (45.8% of recurrence), followed by nodal (25.0%) and "elsewhere lung" (20.8%). The median time to each was 5 to 7 months.

CONCLUSIONS

From the findings of the largest report of SABR for stage T1-T2N0 SCLC to date, SABR (≥50 Gy) with chemotherapy should be considered a standard option.

Abstract 1664: Alpha-tocopheryloxyacetic acid (aTEA) induced immune activation synergizes with radiation therapy to treat primary and metastatic murine mammary carcinoma

Immunotherapy has now emerged as a promising treatment for metastatic cancer. However, immunotherapy for advanced stage breast carcinoma remains an unmet need. Here we demonstrate that the novel immunomodulator alpha-tocopheryloxyacetic acid (aTEA) synergizes with radiation therapy (RT) in a metastatic murine mammary carcinoma model to improve tumor control more than each individual therapy, and we propose a mechanism based on the stimulation of type I interferons by aTEA.

For in-vivo studies, C57BL/6 mice bearing 4T1 murine mammary carcinoma lesions were treated with dietary aTEA, 20 Gy x 2 fractions ionizing radiotherapy, or the combination of aTEA/RT. Immune activation in animals treated with dietary aTEA was determined by analyzing the percentage of proliferating CD4 and CD8 T cells using a Ki-67 assay. Pulmonary metastatic burden was determined using a clonogenic metastasis assay. For in-vitro studies, murine mammary carcinoma cell lines were treated with aTEA or LPS and whole cell lysates were analyzed by Western blot. Expression of interferon regulation factor 3 (IRF3) pathway proteins, including phospho-TANK binding protein kinase 1 (TBK1) and stimulator of interferon genes (STING) were determined.

Our results indicate that treatment with the combination of aTEA and RT significantly improves tumor control compared to either treatment alone. Combination therapy resulted in complete and durable tumor regression in a subset of animals treated, an effect not observed with aTEA or RT alone. Dietary administration of aTEA stimulates proliferation of both CD4 and CD8 T cells and significantly reduces metastatic burden in 4T1 tumor bearing mice. This immune stimulatory effect of aTEA appears to be mediated by reactive oxygen species (ROS) production and release of type I interferons through a STING mediated pathway.

These preliminary results suggest that the combination of aTEA and ionizing radiation may be a viable therapy for the treatment of metastatic breast carcinoma. This therapeutic combination may provide more durable response to radiotherapy while simultaneously reducing further metastatic spread.

Citation Format: Joshua M. Walker, Diego M. Barragan, Melissa J. Kasiewicz, Charles R. Thomas, William L. Redmond. Alpha-tocopheryloxyacetic acid (aTEA) induced immune activation synergizes with radiation therapy to treat primary and metastatic murine mammary carcinoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1664.

Manufacture and evaluation of 3-dimensional printed sizing tools for use during intraoperative breast brachytherapy

Three-dimensional (3D) printing has emerged as a promising modality for the production of medical devices. Here we describe the design, production, and implementation of a series of sizing tools for use in an intraoperative breast brachytherapy program. These devices were produced using a commercially available low-cost 3D printer and software, and their implementation resulted in an immediate decrease in consumable costs without affecting the quality of care or the speed of delivery. This work illustrates the potential of 3D printing to revolutionize the field of medical devices, enabling physicians to rapidly develop and prototype novel tools.

Heterogeneity of the growth phenotype and birth size in acid-labile subunit (ALS) deficiency

PURPOSE

The IGFALS gene encodes the acid-labile subunit (ALS) protein, which regulates circulating IGF-1. Human IGFALS mutations cause growth hormone insensitivity (GHI) associated with ALS, IGF-1 and IGFBP-3 deficiencies and mild to moderate postnatal growth impairment (height SDS -2 to -4). Prenatal growth impairment is not a recognised feature of this disorder, but heterozygous carriers may show an intermediate phenotype.

METHODS

We report a family of five subjects, including three children born small for gestational age, who were investigated for IGFALS gene mutations.

RESULTS

The proband, an 8.7 years female with pre- and postnatal growth failure (BW SDS -3.04, Ht SDS -3.86) and biochemical features of GHI, had a homozygous mutation of IGFALS, c.401T>A; p.L134Q. Her 6.1 years brother (BW SDS -2.11, Ht SDS -2.0) had the same homozygous IGFALS mutation. Both parents [adult height SDS -1.76 (father) and -1.82 (mother)] and her 2.7 years sister (BW SDS -2.60, Ht SDS -2.04) were heterozygous for the IGFALS mutation.

CONCLUSION

Significant phenotypic heterogeneity was observed between family members, in particular varying degrees of prenatal growth retardation were present in the three siblings, which may have contributed to the variation in the postnatal growth phenotype.

Impact of diatomaceous biofilms on the frictional drag of fouling-release coatings

Skin-friction results are presented for fouling-release (FR) hull coatings in the unexposed, clean condition and after dynamic exposure to diatomaceous biofilms for 3 and 6 months. The experiments were conducted in a fully developed turbulent channel flow facility spanning a wide Reynolds number range. The results show that the clean FR coatings tested were hydraulically smooth over much of the Reynolds number range. Biofilms, however, resulted in an increase in skin-friction of up to 70%. The roughness functions for the biofilm-covered surfaces did not display universal behavior, but instead varied with the percentage coverage by the biofilm. The effect of the biofilm was observed to scale with its mean thickness and the square root of the percentage coverage. A new effective roughness length scale (keff) for biofilms based on these parameters is proposed. Boundary layer similarity-law scaling is used to predict the impact of these biofilms on the required shaft power for a mid-sized naval surface combatant at cruising speed. The increase in power is estimated to be between 1.5% and 10.1% depending on the biofilm thickness and percentage coverage.

Impact of broiler processing scalding and chilling profiles on carcass and breast meat yield

The effect of scalding and chilling procedures was evaluated on carcass and breast meat weight and yield in broilers. On 4 separate weeks (trials), broilers were subjected to feed withdrawal, weighed, and then stunned and bled in 4 sequential batches (n = 16 broilers/batch, 64 broilers/trial). In addition, breast skin was collected before scalding, after scalding, and after defeathering for proximate analysis. Each batch of 16 carcasses was subjected to either hard (60.0°C for 1.5 min) or soft (52.8°C for 3 min) immersion scalding. Following defeathering and evisceration, 8 carcasses/batch were air-chilled (0.5°C, 120 min, 86% RH) and 8 carcasses/batch were immersion water-chilled (water and ice 0.5°C, 40 min). Carcasses were reweighed individually following evisceration and following chilling. Breast meat was removed from the carcass and weighed within 4 h postmortem. There were significant (P < 0.05) differences among the trials for all weights and yields; however, postfeed withdrawal shackle weight and postscald-defeathered eviscerated weights did not differ between the scalding and chilling treatments. During air-chilling all carcasses lost weight, resulting in postchill carcass yield of 73.0% for soft-scalded and 71.3% for hard-scalded carcasses, a difference of 1.7%. During water-chilling all carcasses gained weight, resulting in heavier postchill carcass weights (2,031 g) than for air-chilled carcasses (1,899 g). Postchill carcass yields were correspondingly higher for water-chilled carcasses, 78.2% for soft-scalded and 76.1% for hard-scalded carcasses, a difference of 2.1%. Only in trials 1 and 4 was breast meat yield significantly lower for hard-scalded, air-chilled carcasses (16.1 and 17.5%) than the other treatments. Proximate analysis of skin sampled after scalding or defeathering did not differ significantly in moisture (P = 0.2530) or lipid (P = 0.6412) content compared with skin sampled before scalding. Skin protein content was significantly higher (P < 0.05) for prescald and soft-scalded skin samples than for hard-scalded or soft or hard-scalded skin samples after defeathering. The hard-scalding method used in this experiment did not result in increased skin lipid loss either before or after defeathering.

Effects of a metabotropic glutamate receptor 5 positive allosteric modulator, CDPPB, on spatial learning task performance in rodents

Metabotropic glutamate receptor 5 (mGlu5) has been implicated in a variety of learning and memory processes and is important for avoidance learning. The present studies used an mGlu5 receptor positive allosteric modulator, 3-cyano-N-(1,3 diphenyl-1H-hyrazol-5-yl)benzamide (CDPPB), to characterize the importance of mGlu5 receptors in aversively- and appetitively-motivated spatial learning tasks (tasks in which the instrumental contingency involves discriminative cues that differ in spatial location). C57Bl/6 male mice were initially trained in the Barnes maze in the absence of drug. Subsequently, CDPPB (30mg/kg, i.p.), administered 20min prior to each of 3 daily reversal learning training sessions in the Barnes maze, significantly enhanced performance compared to vehicle-treated controls and had a significant effect on search strategy. Mice treated with CDPPB also displayed significantly less perseverative behavior than control-treated animals. In a second experiment, male Sprague-Dawley rats were trained in an appetitively-motivated, delayed alternation version of a T-maze. 30mg/kg CDPPB (s.c.), delivered 20min prior to each of 5 daily training sessions, enhanced the delay rats were able to withstand between the sample and choice portions of each T-maze trial. The present results emphasize the role of mGlu5 receptors in spatial learning tasks and support previous studies which report mGlu5 positive allosteric modulators can enhance learning in some tasks and may have potential as nootropic drugs.

Spatial learning and memory impairment and increased locomotion in a transgenic amyloid precursor protein mouse model of Alzheimer's disease

This study provides an examination of spatial learning and a behavioral assessment of irritability and locomotion in TgCRND8 mice, an amyloid precursor protein transgenic model of Alzheimer's disease. Performance was assessed using the Barnes maze, the touch escape test, and an open-field test. While past research focused primarily on 2-5-month-old TgCRND8 mice, the present study used an older age cohort (9-month-old female mice), in addition to a 4-month-old cohort of both transgenic (Tg) and wildtype female mice. Both younger and older Tg mice displayed poor spatial learning in the Barnes maze task compared to their wildtype littermates, as demonstrated by significantly longer latencies and more errors both during acquisition and at a 2-week retest. No differences in irritability were found between Tg and control mice in the younger cohort; however, older Tg mice displayed significantly higher irritability compared with wildtype littermates, as measured by the touch escape test. Additionally, Tg mice of both age cohorts showed increased locomotion and slowed habituation during a 60-min open-field test over 3 days of testing. These results demonstrate that TgCRND8 mice show significant deficits in spatial and nonspatial behavioral tasks at advanced stages of amyloid pathology.

Disruption of nNOS-PSD95 protein-protein interaction inhibits acute thermal hyperalgesia and chronic mechanical allodynia in rodents

BACKGROUND AND PURPOSE

Post-synaptic density protein 95 (PSD95) contains three PSD95/Dosophilia disc large/ZO-1 homology domains and links neuronal nitric oxide synthase (nNOS) with the N-methyl-D-aspartic acid (NMDA) receptor. This report assesses the effects of disruption of the protein-protein interaction between nNOS and PSD95 on pain sensitivity in rodent models of hyperalgesia and neuropathic pain.

EXPERIMENTAL APPROACH

We generated two molecules that interfered with the nNOS-PSD95 interaction: IC87201, a small molecule inhibitor; and tat-nNOS (residues 1-299), a cell permeable fusion protein containing the PSD95 binding domain of nNOS. We then characterized these inhibitors using in vitro and in vivo models of acute hyperalgesia and chronic allodynia, both of which are thought to require nNOS activation.

KEY RESULTS

IC87201 and tat-nNOS (1-299) inhibited the in vitro binding of nNOS with PSD95, without inhibiting nNOS catalytic activity. Both inhibitors also blocked NMDA-induced 3',5'-cyclic guanosine monophosphate (cGMP) production in primary hippocampal cultures. Intrathecal administration of either inhibitor potently reversed NMDA-induced thermal hyperalgesia in mice. At anti-hyperalgesic doses, there was no effect on acute pain thresholds or motor coordination. Intrathecal administration of IC87201 and tat-nNOS also reversed mechanical allodynia induced by chronic constriction of the sciatic nerve.

CONCLUSIONS AND IMPLICATIONS

nNOS-PSD95 interaction is important in maintaining hypersensitivity in acute and chronic pain. Disruption of the nNOS-PSD95 interaction provides a novel approach to obtain selective anti-hyperalgesic compounds.

Longevity of T-cell memory following acute viral infection

Investigation of T-cell-mediated immunity following acute viral infection represents an area of research with broad implications for both fundamental immunology research as well as vaccine development. Here, we review techniques that are used to assess T-cell memory including limiting dilution analysis, enzyme-linked immunospot (ELISPOT) assays, intracellular cytokine staining (ICCS) and peptide-MHC Class I tetramer staining. The durability of T-cell memory is explored in the context of several acute viral infections including vaccinia virus (VV), measles virus (MV) and yellow fever virus (YFV). Following acute infection, different virus-specific T-cell subpopulations exhibit distinct cytokine profiles and these profiles change over the course of infection. Differential regulation of the cytotoxic proteins, granzyme A, granzyme B and perforin are also observed in virus-specific T cells following infection. As a result of this work, we have gained a broader understanding of the kinetics and magnitude of antiviral T-cell immunity as well as new insight into the patterns of immunodominance and differential regulation of cytokines and cytotoxicity-associated molecules. This information may eventually lead to the generation of more effective vaccines that elicit T-cell memory with the optimal combination of functional characteristics required for providing protective immunity against infectious disease.

Cardiac T2* magnetic resonance for prediction of cardiac complications in thalassemia major

BACKGROUND

The goal of this study was to determine the predictive value of cardiac T2* magnetic resonance for heart failure and arrhythmia in thalassemia major.

METHODS AND RESULTS

We analyzed cardiac and liver T2* magnetic resonance and serum ferritin in 652 thalassemia major patients from 21 UK centers with 1442 magnetic resonance scans. The relative risk for heart failure with cardiac T2* values <10 ms (compared with >10 ms) was 160 (95% confidence interval, 39 to 653). Heart failure occurred in 47% of patients within 1 year of a cardiac T2* <6 ms with a relative risk of 270 (95% confidence interval, 64 to 1129). The area under the receiver-operating characteristic curve for predicting heart failure was significantly greater for cardiac T2* (0.948) than for liver T2* (0.589; P<0.001) or serum ferritin (0.629; P<0.001). Cardiac T2* was <10 ms in 98% of scans in patients who developed heart failure. The relative risk for arrhythmia with cardiac T2* values <20 ms (compared with >20 ms) was 4.6 (95% confidence interval, 2.66 to 7.95). Arrhythmia occurred in 14% of patients within 1 year of a cardiac T2* of <6 ms. The area under the receiver-operating characteristic curve for predicting arrhythmia was significantly greater for cardiac T2* (0.747) than for liver T2* (0.514; P<0.001) or serum ferritin (0.518; P<0.001). The cardiac T2* was <20 ms in 83% of scans in patients who developed arrhythmia.

CONCLUSIONS

Cardiac T2* magnetic resonance identifies patients at high risk of heart failure and arrhythmia from myocardial siderosis in thalassemia major and is superior to serum ferritin and liver iron. Using cardiac T2* for the early identification and treatment of patients at risk is a logical means of reducing the high burden of cardiac mortality in myocardial siderosis. Clinical Trial Registration- URL: http://www.clinicaltrials.gov. Unique identifier: NCT00520559.

Profound CD4+/CCR5+ T cell expansion is induced by CD8+ lymphocyte depletion but does not account for accelerated SIV pathogenesis

Depletion of CD8⁺ lymphocytes during acute simian immunodeficiency virus (SIV) infection of rhesus macaques (RMs) results in irreversible prolongation of peak-level viral replication and rapid disease progression, consistent with a major role for CD8⁺ lymphocytes in determining postacute-phase viral replication set points. However, we report that CD8⁺ lymphocyte depletion is also associated with a dramatic induction of proliferation among CD4⁺ effector memory T (T_EM) cells and, to a lesser extent, transitional memory T (T_TrM) cells, raising the question of whether an increased availability of optimal (activated/proliferating), CD4⁺/CCR5⁺ SIV “target” cells contributes to this accelerated pathogenesis. In keeping with this, depletion of CD8⁺ lymphocytes in SIV⁻ RMs led to a sustained increase in the number of potential CD4⁺ SIV targets, whereas such depletion in acute SIV infection led to increased target cell consumption. However, we found that the excess CD4⁺ T_EM cell proliferation of CD8⁺ lymphocyte–depleted, acutely SIV-infected RMs was completely inhibited by interleukin (IL)-15 neutralization, and that this inhibition did not abrogate the rapidly progressive infection in these RMs. Moreover, although administration of IL-15 during acute infection induced robust CD4⁺ T_EM and T_TrM cell proliferation, it did not recapitulate the viral dynamics of CD8⁺ lymphocyte depletion. These data suggest that CD8⁺ lymphocyte function has a larger impact on the outcome of acute SIV infection than the number and/or activation status of target cells available for infection and viral production.

A comparison of the amino-terminal sequences of two calf-thymus chromatin non-histone proteins

The N-terminal sequences of two calf-thymus non-histone chromosomal proteins, HMG-1 and HMG-2, are compared. Both N-terminal sequences are basic, and differ at only one position. This contrasts with the C-terminal portion of HMG-1 which we have previously shown to be high in acidic residues. There is no obvious sequence homology with any of the known sequences of the histones.

Microsomal omega-hydroxylated metabolites of N-arachidonoyl dopamine are active at recombinant human TRPV1 receptors

N-Arachidonoyl dopamine (NADA) is an endogenous lipid that modulates signal transduction in neuronal and immune pathways. NADA activates the non-selective cation channel, transient receptor potential vanilloid type 1 (TRPV(1)) and cannabinoid receptor 1. That NADA is comprised of an arachidonic acid (AA) backbone suggests that it may be metabolized through many of the enzymes that act upon AA such as the other AA-derived signaling lipids, the endogenous cannabinoids. To investigate the metabolism of NADA through the cytochrome P450 (CYP450) metabolic pathway, we studied the in vitro rat liver microsomal production of hydroxylated metabolites and their activity at recombinant human TRPV(1) receptors. We showed that following microsomal activation in the presence of NADA, omega and (omega-1) hydroxylated metabolites (19- and 20-HETE-DA) were formed. These metabolites were active at recombinant human TRPV(1) receptors, inducing a dose-dependent calcium influx. Both metabolites exhibited lower potency compared to NADA. We conclude that CYP450 enzymes are capable of metabolizing this signaling lipid forming a larger family of potential neuromodulators.

The immunostimulatory power of acute viral infection

In this issue of Immunity, Miller et al. (2008) use multiple independent techniques to demonstrate that antiviral T cell responses after acute human infection are much larger than previously realized.

Induction and evolution of cytomegalovirus-specific CD4+ T cell clonotypes in rhesus macaques

CMV infection induces robust CD4+ T cell responses in immunocompetent hosts that orchestrate immune control of viral replication, dissemination, and disease. In this study, we characterized the clonotypic composition of CD4+ T cell populations specific for rhesus CMV (RhCMV) in chronically infected adult rhesus macaques (RM) and in juvenile RM undergoing primary RhCMV infection and subsequent secondary challenge with RhCMV. In adult RM with established chronic infection, RhCMV-specific CD4+ T cell populations exhibited stable, pauciclonal structures with skewed hierarchies dominated by two or three clonotypes. During primary infection, in contrast, the initial RhCMV-specific CD4+ T cell populations were highly polyclonal and progressive evolution to the chronic pattern manifest in adults occurred over the ensuing 2-3 years. Clear patterns of clonal succession were observed during this maturation process, such that clonotypes present in the acute phase were largely replaced over time. However, rechallenge with RhCMV expanded virus-specific CD4+ T cell clonotypes identified solely during acute infection. These findings indicate that, during persistent viral infection, substantial selection pressures and ongoing clonotype recruitment shape the specific CD4+ T cell repertoire and that rapidly exhausted or superseded clonotypes often remain within the memory T cell pool.

Compartmentalization of endocannabinoids into lipid rafts in a dorsal root ganglion cell line

BACKGROUND AND PURPOSE

N-arachidonoyl ethanolamine (AEA) and 2-arachidonoyl glycerol (2-AG) are endogenous cannabinoids binding to the cannabinoid receptors CB1 and CB2 to modulate neuronal excitability and synaptic transmission in primary afferent neurons. To investigate the compartmentalization of the machinery for AEA and 2-AG signalling, we studied their partitioning into lipid raft fractions isolated from a dorsal root ganglion X neuroblastoma cell line (F-11).

EXPERIMENTAL APPROACH

F-11 cells were homogenized and fractionated using a detergent-free OptiPrep density gradient. All lipids were partially purified from methanolic extracts of the fractions on solid phase cartridges and quantified using liquid chromatography tandem mass spectrometry (LC/MS/MS). Protein distribution was determined by Western blotting.

KEY RESULTS

Under basal conditions, the endogenous cannabinoid AEA was present in both lipid raft and specific non-lipid raft fractions as was one of its biosynthetic enzymes, NAPE-PLD. The 2-AG precursor 1-stearoyl-2-arachidonoyl-sn-glycerol (DAG), diacylglycerol lipase alpha (DAGLalpha), which cleaves DAG to form 2-AG, and 2-AG were all co-localized with lipid raft markers. CB1 receptors, previously reported to partition into lipid raft fractions, were not detected in F-11 membranes, but CB2 receptors were detected at high levels and partitioned into non-lipid raft fractions.

CONCLUSIONS AND IMPLICATIONS

The biochemical machinery for the production of 2-AG via the putative diacylglycerol pathway is localized within lipid rafts, suggesting that 2-AG synthesis via DAG occurs within these microdomains. The observed co-localization of AEA, 2-AG, and their synthetic enzymes with the reported localization of CB1 raises the possibility of intrinsic-autocrine signalling within lipid raft domains and/or retrograde-paracrine signalling.

Reproductive function for a C-terminus extended, male-transmitted cytochrome c oxidase subunit II protein expressed in both spermatozoa and eggs

Our previous study documented expression of a male-transmitted cytochrome c oxidase subunit II protein (MCOX2), with a C-terminus extension (MCOX2e), in unionoidean bivalve testes and sperm mitochondria. Here, we present evidence demonstrating that MCOX2 is seasonally expressed in testis, with a peak shortly before fertilization that is independent of sperm density. MCOX2 is localized to the inner and outer sperm mitochondrial membranes and the MCOX2 antibody's epitope is conserved across >65 million years of evolution. We also demonstrate the presence of male-transmitted mtDNA and season-specific MCOX2 spatial variation in ovaries. We hypothesize that MCOX2 plays a role in reproduction through gamete maturation, fertilization and/or embryogenesis.

The endocannabinoid system and rimonabant: a new drug with a novel mechanism of action involving cannabinoid CB1 receptor antagonism--or inverse agonism--as potential obesity treatment and other therapeutic use

There is considerable evidence that the endocannabinoid (endogenous cannabinoid) system plays a significant role in appetitive drive and associated behaviours. It is therefore reasonable to hypothesize that the attenuation of the activity of this system would have therapeutic benefit in treating disorders that might have a component of excess appetitive drive or over-activity of the endocannabinoid system, such as obesity, ethanol and other drug abuse, and a variety of central nervous system and other disorders. Towards this end, antagonists of cannabinoid receptors have been designed through rational drug discovery efforts. Devoid of the abuse concerns that confound and impede the use of cannabinoid receptor agonists for legitimate medical purposes, investigation of the use of cannabinoid receptor antagonists as possible pharmacotherapeutic agents is currently being actively investigated. The compound furthest along this pathway is rimonabant, a selective CB(1) (cannabinoid receptor subtype 1) antagonist, or inverse agonist, approved in the European Union and under regulatory review in the United States for the treatment of obesity. This article summarizes the basic science of the endocannabinoid system and the therapeutic potential of cannabinoid receptor antagonists, with emphasis on the treatment of obesity.

Altered claudin expression is a feature of chronic plaque psoriasis

Epithelial tight junctions play a central role in cell-cell adhesion and are necessary for the selective paracellular movement of ions. Claudins are key components of tight junctions and their expression is altered in gut epithelia in a variety of inflammatory enteropathies, including ulcerative colitis and Crohn's disease. Psoriasis is a chronic inflammatory skin disease affecting approximately 2% of the western population, with significantly increased occurrence in individuals with Crohn's disease. Initial studies investigated the expression of claudins in skin of healthy volunteers and patients with chronic plaque psoriasis. We report here that claudins-1 and -3 are the major protein species present in the epidermis of healthy skin; they are expressed on the surface of epidermal keratinocytes, consistent with their localization to tight junctions. In plaques of psoriasis, claudin-1 was not identifiable in the epidermis, although typical staining patterns were observed in clinically normal, uninvolved skin of patients with psoriasis. Claudin-3 was present in the epidermal granular cell layer in normal skin, but was only identified within the cytosol of epidermal keratinocytes in both involved and uninvolved skin of psoriasis patients. We examined further whether exposure of keratinocytes in vitro to pro-inflammatory cytokines mimicked the observed changes in claudin expression seen in chronic plaque psoriasis; lipopolysaccharide, interferon-gamma and tumour necrosis factor-alpha had no effect on claudin protein expression or distribution. Addition of interleukin-1beta, however, resulted in down-regulation of claudins-1 and -3. Tumour necrosis factor-alpha and interleukin-1beta were further used in an in vivo model of skin inflammation; interleukin-1beta alone modulated claudin protein expression in this system. These data demonstrate that epidermal claudin expression is altered in chronic plaque psoriasis and that expression is in part modulated by interleukin-1beta.

Progressive CD4+ central memory T cell decline results in CD4+ effector memory insufficiency and overt disease in chronic SIV infection

Primary simian immunodeficiency virus (SIV) infections of rhesus macaques result in the dramatic depletion of CD4⁺ CCR5⁺ effector–memory T (T_EM) cells from extra-lymphoid effector sites, but in most infections, an increased rate of CD4⁺ memory T cell proliferation appears to prevent collapse of effector site CD4⁺ T_EM cell populations and acute-phase AIDS. Eventually, persistent SIV replication results in chronic-phase AIDS, but the responsible mechanisms remain controversial. Here, we demonstrate that in the chronic phase of progressive SIV infection, effector site CD4⁺ T_EM cell populations manifest a slow, continuous decline, and that the degree of this depletion remains a highly significant correlate of late-onset AIDS. We further show that due to persistent immune activation, effector site CD4⁺ T_EM cells are predominantly short-lived, and that their homeostasis is strikingly dependent on the production of new CD4⁺ T_EM cells from central–memory T (T_CM) cell precursors. The instability of effector site CD4⁺ T_EM cell populations over time was not explained by increasing destruction of these cells, but rather was attributable to progressive reduction in their production, secondary to decreasing numbers of CCR5⁻ CD4⁺ T_CM cells. These data suggest that although CD4⁺ T_EM cell depletion is a proximate mechanism of immunodeficiency, the tempo of this depletion and the timing of disease onset are largely determined by destruction, failing production, and gradual decline of CD4⁺ T_CM cells.

A randomized, placebo-controlled, double-blind trial of the effect of combined therapy with deferoxamine and deferiprone on myocardial iron in thalassemia major using cardiovascular magnetic resonance

BACKGROUND

Cardiac complications secondary to iron overload are the leading cause of death in beta-thalassemia major. Approximately two thirds of patients maintained on the parenteral iron chelator deferoxamine have myocardial iron loading. The oral iron chelator deferiprone has been demonstrated to remove myocardial iron, and it has been proposed that in combination with deferoxamine it may have additional effect.

METHODS AND RESULTS

Myocardial iron loading was assessed with the use of myocardial T2* cardiovascular magnetic resonance in 167 patients with thalassemia major receiving standard maintenance chelation monotherapy with subcutaneous deferoxamine. Of these patients, 65 with mild to moderate myocardial iron loading (T2* 8 to 20 ms) entered the trial with continuation of subcutaneous deferoxamine and were randomized to receive additional oral placebo (deferoxamine group) or oral deferiprone 75 mg/kg per day (combined group). The primary end point was the change in myocardial T2* over 12 months. Secondary end points of endothelial function (flow-mediated dilatation of the brachial artery) and cardiac function were also measured with cardiovascular magnetic resonance. There were significant improvements in the combined treatment group compared with the deferoxamine group in myocardial T2* (ratio of change in geometric means 1.50 versus 1.24; P=0.02), absolute left ventricular ejection fraction (2.6% versus 0.6%; P=0.05), and absolute endothelial function (8.8% versus 3.3%; P=0.02). There was also a significantly greater improvement in serum ferritin in the combined group (-976 versus -233 microg/L; P<0.001).

CONCLUSIONS

In comparison to the standard chelation monotherapy of deferoxamine, combination treatment with additional deferiprone reduced myocardial iron and improved the ejection fraction and endothelial function in thalassemia major patients with mild to moderate cardiac iron loading.

Anti-OX40 (CD134) administration to nonhuman primates: immunostimulatory effects and toxicokinetic study

The immune-stimulatory properties of anti-CD134 (OX40) antibodies have been well documented in rodents, including their ability to enhance antitumor immunity. In this study, an anti-OX40 antibody (Ab) known to costimulate monkey T cells in vitro, was infused into rhesus macaque monkeys during immunization with the simian immunodeficiency virus protein, gp130. The draining lymph nodes from immunized monkeys treated with anti-OX40 were enlarged compared with immunized monkeys injected with mouse Ig. Anti-OX40-treated monkeys had increased gp130-specific Ab titers, and increased long-lived T-cell responses, compared with controls. There were no overt signs of toxicity in the anti-OX40-treated monkeys. The encouraging immune-stimulatory effects led to the good manufacturing practice production of an anti-OX40 Ab for clinical trials in cancer patients. A detailed toxicology study was performed with anti-OX40 in nonhuman primates. Three groups of 8 monkeys received anti-OX40 at 1 of 3 dose levels (0.4, 2.0, and 10 mg/kg) and a control group received saline. No clinical toxicity was observed, but acute splenomegaly and enlarged gut-associated lymph nodes were observed in the anti-OX40-treated animals; splenomegaly and lymphadenopathy resolved by day 28. These studies demonstrate the immune-stimulatory properties and safety of anti-OX40 in primates and provide a strong scientific rationale to pursue clinical trials in humans.

Myocardial iron loading in patients with thalassemia major on deferoxamine chelation

BACKGROUND

Heart failure secondary to myocardial iron loading remains the leading cause of death in thalassemia major (TM). We used cardiovascular magnetic resonance (CMR) to assess the prevalence of myocardial iron overload and ventricular dysfunction in a large cohort of TM patients maintained on conventional chelation treatment with deferoxamine.

METHODS

A mobile CMR scanner was transported from London, UK, to Sardinia, Italy where 167 TM patients were assessed for myocardial iron loading, B-natriuretic peptide (BNP), and ferritin. In patients with myocardial iron loading CMR assessments of ventricular function were also made.

RESULTS

Myocardial iron loading (T2* < 20 ms) was present in 108 (65%) patients, which was severe (T2* < 8 ms) in 22 (13%). Impaired (< 56%) left ventricular (LV) ejection fraction (EF) was present in 5%, 20% and 62% of patients with mild, moderate or severe iron loading. Increasing myocardial iron was related to impaired LVEF (Rs = 0.57, p < 0.001), weakly related to serum ferritin (Rs = -0.34, p < 0.001), and not related to liver iron (Rs = 0.11, p = 0.26). BNP was weakly related to myocardial iron (Rs = -0.35, p < 0.001) and was abnormal in only 5 patients.

CONCLUSIONS

Myocardial siderosis was found in two-thirds of thalassemia major patients on maintenance deferoxamine treatment. This was combined with a high prevalence of impaired LV function, the severity of which tracked the severity of iron deposition. BNP was not useful to assess myocardial siderosis.

Experimental metastasis and primary tumor growth in mice with hemophilia A

During experimental lung metastasis, tumor cells adhere to the pulmonary microvasculature and activate coagulation via surface-expressed tissue factor (TF), leading to local fibrin deposition and platelet aggregation. While interventional studies have demonstrated great efficacy of anticoagulants and antiplatelet agents in inhibiting metastasis, no information is available on how tumor biology may be affected by congenital bleeding disorders such as hemophilia A. We therefore used a syngeneic model to study experimental metastasis and primary tumor growth in factor VIII (FVIII)-deficient mice. By conventional reverse transcription-polymerase chain reaction, flow cytometry, and one-stage clotting assays, we demonstrated constitutive expression of TF mRNA, antigen, and procoagulant activity in the murine B16F10 melanoma cell line. In hemophilic mice, B16F10 lung metastasis was significantly (P < 0.001) enhanced by a single dose of human FVIII (100 U kg(-1)), suggesting that FVIII played a critical role during the early blood-borne phase of the metastatic cascade. In contrast, lung seeding was significantly (P < 0.05) reduced by lepirudin, a direct thrombin inhibitor, suggesting that thrombin generation contributed to pulmonary metastasis even in the absence of FVIII. Consistent with this finding, intravenous injection of B16F10 cell-evoked laboratory changes of a hemolytic thrombotic microangiopathy and consumptive coagulopathy in both hemophilic and non-hemophilic mice. Subcutaneous implantation of B16F10 cells into mice with hemophilia A gave rise to primary tumors in an exponential growth pattern similar to that observed in non-hemophilic mice. Although TF expression by B16F10 cells may promote thrombin-dependent metastasis in mice with hemophilia A, amplification of coagulation by host FVIII appears to be necessary for maximum lung seeding.

Presence of a unique male-specific extension of C-terminus to the cytochrome c oxidase subunit II protein coded by the male-transmitted mitochondrial genome of Venustaconcha ellipsiformis (Bivalvia: Unionoidea)

Analyses of unionoidean bivalve male-transmitted (M) mtDNA genomes revealed an approximately 555 bp 3' coding extension to cox2. An antibody was generated against this predicted C-terminus extension to determine if the unique cox2 protein is expressed. Western blot and immunohistochemistry analyses demonstrated that the protein was predominantly expressed in testes. Weak expression was detected in other male tissues but the protein was not detected in female tissues. This is the first report documenting the expression of a cox2 protein with a long C-terminus in animals. Its universal presence in unionoidean bivalve testes suggests a functional significance for the protein.

Cannabinoid mechanisms of pain suppression

A large body of literature indicates that cannabinoids suppress behavioral responses to acute and persistent noxious stimulation in animals. This review examines neuroanatomical, behavioral, and neurophysiological evidence supporting a role for cannabinoids in suppressing pain at spinal, supraspinal, and peripheral levels. Localization studies employing receptor binding and quantitative autoradiography, immunocytochemistry, and in situ hybridization are reviewed to examine the distribution of cannabinoid receptors at these levels and provide a neuroanatomical framework with which to understand the roles of endogenous cannabinoids in sensory processing. Pharmacological and transgenic approaches that have been used to study cannabinoid antinociceptive mechanisms are described. These studies provide insight into the functional roles of cannabinoid CB1 (CB1R) and CB2 (CB2R) receptor subtypes in cannabinoid antinociceptive mechanisms, as revealed in animal models of acute and persistent pain. The role of endocannabinoids and related fatty acid amides that are implicated in endogenous mechanisms for pain suppression are discussed. Human studies evaluating therapeutic potential of cannabinoid pharmacotherapies in experimental and clinical pain syndromes are evaluated. The potential of exploiting cannabinoid antinociceptive mechanisms in novel pharmacotherapies for pain is discussed.

Insufficient production and tissue delivery of CD4+ memory T cells in rapidly progressive simian immunodeficiency virus infection

The mechanisms linking human immunodeficiency virus replication to the progressive immunodeficiency of acquired immune deficiency syndrome are controversial, particularly the relative contribution of CD4⁺ T cell destruction. Here, we used the simian immunodeficiency virus (SIV) model to investigate the relationship between systemic CD4⁺ T cell dynamics and rapid disease progression. Of 18 rhesus macaques (RMs) infected with CCR5-tropic SIVmac239 (n = 14) or CXCR4-tropic SIVmac155T3 (n = 4), 4 of the former group manifested end-stage SIV disease by 200 d after infection. In SIVmac155T3 infections, naive CD4⁺ T cells were dramatically depleted, but this population was spared by SIVmac239, even in rapid progressors. In contrast, all SIVmac239-infected RMs demonstrated substantial systemic depletion of CD4⁺ memory T cells by day 28 after infection. Surprisingly, the extent of CD4⁺ memory T cell depletion was not, by itself, a strong predictor of rapid progression. However, in all RMs destined for stable infection, this depletion was countered by a striking increase in production of short-lived CD4⁺ memory T cells, many of which rapidly migrated to tissue. In all rapid progressors (P < 0.0001), production of these cells initiated but failed by day 42 of infection, and tissue delivery of new CD4⁺ memory T cells ceased. Thus, although profound depletion of tissue CD4⁺ memory T cells appeared to be a prerequisite for early pathogenesis, it was the inability to respond to this depletion with sustained production of tissue-homing CD4⁺ memory T cells that best distinguished rapid progressors, suggesting that mechanisms of the CD4⁺ memory T cell generation play a crucial role in maintaining immune homeostasis in stable SIV infection.