Long-term treatment with eteplirsen in nonambulatory patients with Duchenne muscular dystrophy

This analysis aims to describe the outcomes of two nonambulatory patients with Duchenne muscular dystrophy (DMD) who participated in two clinical studies. The two consecutive trials of eteplirsen (studies 201 and 202) were conducted in patients with DMD (N = 12) and confirmed genetic mutations amenable to exon 51 skipping.In study 201, 12 patients were randomized to receive once-weekly, double-blind intravenous infusions of eteplirsen 30 or 50 mg/kg or placebo for 24 weeks; patients then received open-label eteplirsen during weeks 25 through 28. All 12 patients continued onto open-label extension study 202 and received long-term treatment with eteplirsen. We compared cardiac, pulmonary, and upper limb function and dystrophin production in the nonambulatory twin patients versus the 10 ambulatory patients through 240 combined treatment weeks.Ten study patients remained ambulatory through both studies, while the identical twin patients both experienced early, rapid loss of ambulation. The twin patients had greater disease severity at baseline (6-minute walk test [6MWT], 330 and 256 m) versus the other patients (n = 10; 6MWT range, 341-418 m). They maintained cardiac and upper limb function through combined week 240, with outcomes similar to those of the patients who remained ambulatory. Dystrophin production was confirmed following eteplirsen treatment.Despite the loss of ambulation, other markers of disease progression remained relatively stable in the eteplirsen-treated twin patients and were similar to those of the ambulatory patients.

Validation of a Muscle-Specific Tissue Image Analysis Tool for Quantitative Assessment of Dystrophin Staining in Frozen Muscle Biopsies

CONTEXT.—

Duchenne muscular dystrophy is a rare, progressive, and fatal neuromuscular disease caused by dystrophin protein loss. Common investigational treatment approaches aim at increasing dystrophin expression in diseased muscle. Some clinical trials include assessments of novel dystrophin production as a surrogate biomarker of efficacy, which may predict a clinical benefit from treatment.

OBJECTIVES.—

To establish an immunofluorescent scanning and digital image analysis workflow that provides an objective approach for staining intensity assessment of the immunofluorescence dystrophin labeling and determination of the percentage of biomarker-positive fibers in muscle cryosections.

DESIGN.—

Optimal and repeatable digital image capture was achieved by a rigorously qualified fluorescent scanning process. After scanning qualification, the MuscleMap (Flagship Biosciences, Westminster, Colorado) algorithm was validated by comparing high-power microscopic field total and dystrophin-positive fiber counts obtained by trained pathologists to data derived by MuscleMap. Next, the algorithm was tested on whole-slide images of immunofluorescent-labeled muscle sections from Duchenne muscular dystrophy, Becker muscular dystrophy, and control patients.

RESULTS.—

When used under the guidance of a trained pathologist, the digital image analysis tool met predefined validation criteria and demonstrated functional and statistical equivalence with manual assessment. This work is the first, to our knowledge, to qualify and validate immunofluorescent scanning and digital tissue image-analysis workflow, respectively, with the rigor required to support the clinical trial environments.

CONCLUSIONS.—

MuscleMap enables analysis of all fibers within an entire muscle biopsy section and provides data on a fiber-by-fiber basis. This will allow future clinical trials to objectively investigate myofibers' dystrophin expression at a greater level of consistency and detail.

Abstract 1694: Computational analysis of multiplexed immunohistochemistry for understanding immune profiles in clinical biopsies

Using immunohistochemistry (IHC) to examine immune infiltrates in tissue biopsies to support exploratory investigations for immuno-oncology drug development is critical for understanding the abundance and spatial relationships of different immune cell types and how they may change with drug treatment. Multiplex IHC approaches are utilized to examine these types of pharmacodynamic responses because of the limited tissue available from repeat needle core biopsies and the need to visualize multiple biomarkers in the same tissue section. While several different methods of fluorescent multiplexing approaches exist, the complexity of these fluorescent assays limits the ability to develop and validate bespoke assays to meet the needs of hypothesis-driven research which aims to elucidate predictors of clinical response. Furthermore, these methodologies present known challenges for design control processes and regulatory approval as companion diagnostics, preventing wide use beyond exploratory research settings.

In contrast, development and analytical validation of chromogenic IHC assays enables an agile and bespoke approach to IHC assay development which can support all phases drug development, including direct translations of these methods into companion diagnostic building approaches. However, investigating multiple biomarkers using chromogenic assays presents its own challenges, as there is a more limited repertoire of chromagens than fluorophores, which have significant spectral overlap in wavelength absorbance and optical density. As such, a multiplex chromogenic IHC assay requires specialized performance specifications as well as sophisticated interpretation methods to ensure accurate interpretations.

While these limitations often create too great a challenge for pathologists to interpret, computational analysis of tissue using Flagship's cTA™ platform resolves these challenges and enables drug developers to rely on chromogenic IHC approaches to meet the needs of drug and diagnostic development. To demonstrate the application of this method, we developed several chromogenic multiplex IHC assays which capture critical immune profiles for immuno-oncology studies and interpreted the endpoints using Flagship's cTA™ approach. These assays/interpretations provide quantitative data about: 1) General immune profile (CD8/CD68/FoxP3); 2) T-cell ratio (CD3/CD8); 3)T-cell activation (CD8/Ki67); and 4) T-cell suppression (CD8/FoxP3). Using this approach, we demonstrate how Flagship's cTA™ platform enables investigation of complex biological questions using chromogenic assays, which cannot be achieved by relying on traditional manual pathology interpretation.

Citation Format: Joseph S. Krueger, Brooke Hirsch, Mandy Bell, Karen Ryall, Nick Landis, G David Young, Kile McFadden, Ben Landis. Computational analysis of multiplexed immunohistochemistry for understanding immune profiles in clinical biopsies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1694.

Eteplirsen treatment for Duchenne muscular dystrophy: Exon skipping and dystrophin production

OBJECTIVE

To describe the quantification of novel dystrophin production in patients with Duchenne muscular dystrophy (DMD) after long-term treatment with eteplirsen.

METHODS

Clinical study 202 was an observational, open-label extension of the randomized, controlled study 201 assessing the safety and efficacy of eteplirsen in patients with DMD with a confirmed mutation in the DMD gene amenable to correction by skipping of exon 51. Patients received once-weekly IV doses of eteplirsen 30 or 50 mg/kg. Upper extremity muscle biopsy samples were collected at combined study week 180, blinded, and assessed for dystrophin-related content by Western blot, Bioquant software measurement of dystrophin-associated immunofluorescence intensity, and percent dystrophin-positive fibers (PDPF). Results were contrasted with matched untreated biopsies from patients with DMD. Reverse transcription PCR followed by Sanger sequencing of newly formed slice junctions was used to confirm the mechanism of action of eteplirsen.

RESULTS

Reverse transcription PCR analysis and sequencing of the newly formed splice junction confirmed that 100% of treated patients displayed the expected skipped exon 51 sequence. In treated patients vs untreated controls, Western blot analysis of dystrophin content demonstrated an 11.6-fold increase (p = 0.007), and PDPF analysis demonstrated a 7.4-fold increase (p < 0.001). The PDPF findings were confirmed in a re-examination of the sample (15.5-fold increase, p < 0.001). Dystrophin immunofluorescence intensity was 2.4-fold greater in treated patients than in untreated controls (p < 0.001).

CONCLUSION

Taken together, the 4 assays, each based on unique evaluation mechanisms, provided evidence of eteplirsen muscle cell penetration, exon skipping, and induction of novel dystrophin expression.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence of the muscle cell penetration, exon skipping, and induction of novel dystrophin expression by eteplirsen, as confirmed by 4 assays.

Duchenne and Becker Muscular Dystrophies: A Review of Animal Models, Clinical End Points, and Biomarker Quantification

Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) are neuromuscular disorders that primarily affect boys due to an X-linked mutation in the DMD gene, resulting in reduced to near absence of dystrophin or expression of truncated forms of dystrophin. Some newer therapeutic interventions aim to increase sarcolemmal dystrophin expression, and accurate dystrophin quantification is critical for demonstrating pharmacodynamic relationships in preclinical studies and clinical trials. Current challenges with measuring dystrophin include the variation in protein expression within individual muscle fibers and across whole muscle samples, the presence of preexisting dystrophin-positive revertant fibers, and trace amounts of residual dystrophin. Immunofluorescence quantification of dystrophin can overcome many of these challenges, but manual quantification of protein expression may be complicated by variations in the collection of images, reproducible scoring of fluorescent intensity, and bias introduced by manual scoring of typically only a few high-power fields. This review highlights the pathology of DMD and BMD, discusses animal models of DMD and BMD, and describes dystrophin biomarker quantitation in DMD and BMD, with several image analysis approaches, including a new automated method that evaluates protein expression of individual muscle fibers.

Quantitative assessment of pancreatic cancer precursor lesions in IHC-stained tissue with a tissue image analysis platform

Tissue image analysis (tIA) is emerging as a powerful tool for quantifying biomarker expression and distribution in complex diseases and tissues. Pancreatic ductal adenocarcinoma (PDAC) develops in a highly complex and heterogeneous tissue environment and, generally, has a very poor prognosis. Early detection of PDAC is confounded by limited knowledge of the pre-neoplastic disease stages and limited methods to quantitatively assess disease heterogeneity. We sought to develop a tIA approach to assess the most common PDAC precursor lesions, pancreatic intraepithelial neoplasia (PanIN), in tissues from Kras^LSL-G12D/+; Trp53^LSL-R172H/+; Pdx-Cre (KPC) mice, a validated model of PDAC development. tIA profiling of training regions of PanIN and tumor microenvironment (TME) cells was utilized to guide identification of PanIN/TME tissue compartment stratification criteria. A custom CellMap algorithm implementing these criteria was applied to whole-slide images of KPC mice pancreata sections to quantify p53 and Ki-67 biomarker staining in each tissue compartment as a proof-of-concept for the algorithm platform. The algorithm robustly identified a higher percentage of p53-positive cells in PanIN lesions relative to the TME, whereas no difference was observed for Ki-67. Ki-67 expression was also quantified in a human pancreatic tissue sample available to demonstrate the translatability of the CellMap algorithm to human samples. Together, our data demonstrated the utility of CellMap to enable objective and quantitative assessments, across entire tissue sections, of PDAC precursor lesions in preclinical and clinical models of this disease to support efforts leading to novel insights into disease progression, diagnostic markers, and potential therapeutic targets.

Commentary

Historically, pathologists perform manual evaluation of H&E- or immunohistochemically-stained slides, which can be subjective, inconsistent, and, at best, semiquantitative. As the complexity of staining and demand for increased precision of manual evaluation increase, the pathologist’s assessment will include automated analyses (i.e., “digital pathology”) to increase the accuracy, efficiency, and speed of diagnosis and hypothesis testing and as an important biomedical research and diagnostic tool. This commentary introduces the many roles for pathologists in designing and conducting high-throughput digital image analysis. Pathology review is central to the entire course of a digital pathology study, including experimental design, sample quality verification, specimen annotation, analytical algorithm development, and report preparation. The pathologist performs these roles by reviewing work undertaken by technicians and scientists with training and expertise in image analysis instruments and software. These roles require regular, face-to-face interactions between team members and the lead pathologist. Traditional pathology training is suitable preparation for entry-level participation on image analysis teams. The future of pathology is very exciting, with the expanding utilization of digital image analysis set to expand pathology roles in research and drug development with increasing and new career opportunities for pathologists.

Evaluating tumor heterogeneity in immunohistochemistry-stained breast cancer tissue

Quantitative clinical measurement of heterogeneity in immunohistochemistry staining would be useful in evaluating patient therapeutic response and in identifying underlying issues in histopathology laboratory quality control. A heterogeneity scoring approach (HetMap) was designed to visualize a individual patient's immunohistochemistry heterogeneity in the context of a patient population. HER2 semiquantitative analysis was combined with ecology diversity statistics to evaluate cell-level heterogeneity (consistency of protein expression within neighboring cells in a tumor nest) and tumor-level heterogeneity (differences of protein expression across a tumor as represented by a tissue section). This approach was evaluated on HER2 immunohistochemistry-stained breast cancer samples using 200 specimens across two different laboratories with three pathologists per laboratory, each outlining regions of tumor for scoring by automatic cell-based image analysis. HetMap was evaluated using three different scoring schemes: HER2 scoring according to American Society of Clinical Oncology and College of American Pathologists (ASCO/CAP) guidelines, H-score, and a new continuous HER2 score (HER2(cont)). Two definitions of heterogeneity, cell-level and tumor-level, provided useful independent measures of heterogeneity. Cases where pathologists had disagreement over reads in the area of clinical importance (+1 and +2) had statistically significantly higher levels of tumor-level heterogeneity. Cell-level heterogeneity, reported either as an average or the maximum area of heterogeneity across a slide, had low levels of dependency on the pathologist choice of region, while tumor-level heterogeneity measurements had more dependence on the pathologist choice of regions. HetMap is a measure of heterogeneity, by which pathologists, oncologists, and drug development organizations can view cell-level and tumor-level heterogeneity for a patient for a given marker in the context of an entire patient cohort. Heterogeneity analysis can be used to identify tumors with differing degrees of heterogeneity, or to highlight slides that should be rechecked for QC issues. Tumor heterogeneity plays a significant role in disconcordant reads between pathologists.

Abstract 2683: Cellmap: Tumor cell subpopulation analysis in immunohistochemistry stained tumor tissue

All potential factors within individual patients which contribute to a lack of response to a given therapy are not known, but cancer biologists have long hypothesized that distinct and disparate populations within the tumor can be selected for by therapy to outgrow and emerge as a resistant tumor. As more targeted therapies are being developed, the understanding of these subpopulations of cells within a tumor has become very important to clinical strategy. Thus, there is a need to effectively distinguish and evaluate different populations of cells in a tumor within formalin fixed tissue. These contextual evaluations are important for understanding the biology of a target, evaluating pharmacodynamic or surrogate efficacy markers, or evaluating biomarkers for a companion diagnostic approach. Immunohistochemistry (IHC) remains the most direct approach to evaluating biomarkers within tissue context, but requires a pathologist to subjectively separate the complex components of tumor tissue and the compartments of the tumor cells themselves to deliver a numerical score that is based on the staining intensity of a cell and the percentage of cells which stain. This output is considered qualitative, due to pathologist subjectivity in scoring sample regions, the inability to effectively discriminate minor differences in staining intensities for a biomarker, and the inability to deliver a dataset with sufficient sample size to overcome bias deficiencies. Furthermore, a significant amount of information content is lost in this score, eliminating the potential to identify and analyze discrete cell populations within a tumor that may be leading to refractory to therapy. In contrast, modern image analysis (IA) approaches can deliver a far more quantitative IHC score by objectively distinguishing tumor components and cellular compartments, detecting minor differences in staining intensity, and by performing this function across the whole tumor section. However, current IA approaches are designed only to report an average or thresholded intensity across the analyzed region, without reporting the cell-by-cell statistics required to identify discrete cell populations within a tumor. To answer this, we have designed Cellmap, which can analyze an IHC stained tumor tissue section which has been digitally imaged, and make multiparametric measurements about cell morphology and biomarker staining in every cell individually. This information can be reported tumor-wide, or within a specific component of the tumor, and/or within a compartment of the cell simultaneously. Cellmap can be used to make quantitative measurements which identify specific cells with specific signaling processes, and determine their location within a tumor section. This information can be used to identify and quantify discrete cell populations relevant to a disease hypothesis which are associated with a specific tumor microenvironment.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2683. doi:1538-7445.AM2012-2683

The evaluation of E-Cadherin and vimentin as biomarkers of clinical outcomes among patients with non-small cell lung cancer treated with erlotinib as second- or third-line therapy

E-Cadherin and vimentin protein expression was assessed in late stage non-small cell lung cancer tumors from the placebo controlled clinical trial, NCIC-CTG BR.21, to determine if these markers had the potential to predict outcome of erlotinib therapy. E-Cadherin and vimentin protein expression levels were assessed in tumors from 95 patients, who were representative of the overall population, using semi-quantitative immunohistochemistry. The percentage of tumor cells with grades 0, 1, 2, or 3 membrane staining of E-cadherin and cytoplasmic staining of vimentin was measured. Three scoring methods and multiple cut-offs were explored to determine if these markers were able to divide patients into groups with different overall survival (OS). A cut-off point for E-cadherin of ≥40% tumor cells with staining of +2 and +3 and a cut-off for vimentin of ≥10% of tumors cell with any staining provided the optimal stratification. The OS hazard ratio (HR) for E-cadherin(+) versus E-cadherin(-) in the erlotinib-treated patients was 0.68 (0.35-1.33) compared with 1.48 (0.69-3.15) in the placebo patients and the OS (HR) for erlotinib versus placebo was 0.47 (0.26-0.88) in E-cadherin(+) patients compared with 1.12 (0.52-2.44) in the E-cadherin(-) patients. The OS (HR) for vimentin(+) versus vimentin(-) in the erlotinib-treated patients was 0.65 (0.31-1.38) compared to 2.32 (1.09-4.94) in the placebo-treated patients and the OS (HR) for erlotinib versus placebo was 0.26 (0.11-0.63) in vimentin(+) compared to 0.99 (0.55-1.76) in the vimentin(-) patients. Similar trends were observed for progression-free survival and response rate. E-Cadherin and vimentin are biomarkers worthy of additional study as predictive markers of outcome of erlotinib therapy.

Inducible expression of TGFβ, snail and Zeb1 recapitulates EMT in vitro and in vivo in a NSCLC model

The progression of cancer from non-metastatic to metastatic is the critical transition in the course of the disease. The epithelial to mesenchymal transition (EMT) is a mechanism by which tumor cells acquire characteristics that improve metastatic efficiency. Targeting EMT processes in patients is therefore a potential strategy to block the transition to metastatic cancer and improve patient outcome. To develop models of EMT applicable to in vitro and in vivo settings, we engineered NCI-H358 non-small cell lung carcinoma cells to inducibly express three well-established drivers of EMT: activated transforming growth factor β (aTGFβ), Snail or Zeb1. We characterized the morphological, molecular and phenotypic changes induced by each of the drivers and compared the different end-states of EMT between the models. Both in vitro and in vivo, induction of the transgenes Snail and Zeb1 resulted in downregulation of epithelial markers and upregulation of mesenchymal markers, and reduced the ability of the cells to proliferate. Induced autocrine expression of aTGFβ caused marker and phenotypic changes consistent with EMT, a modest effect on growth rate, and a shift to a more invasive phenotype. In vivo, this manifested as tumor cell infiltration of the surrounding mouse stromal tissue. Overall, Snail and Zeb1 were sufficient to induce EMT in the cells, but aTGFβ induced a more complex EMT, in which changes in extracellular matrix remodeling components were pronounced.

The role and impact of quantitative discovery pathology

The decision to advance an early-stage compound into formal preclinical testing depends on confidence in mechanism, efficacy and toxicity profiles. A substantial percentage of this confidence comes from histopathology interpretation, as the local tissue environment contains strong signals of both efficacy and toxicity. Accessing this tissue information is made difficult by biological variability across organs and tissues, an insufficient pool of pathology experts working in discovery, and the high subjectivity and individual isolation of microscope-based observations. This article describes how whole-slide imaging and quantitative analysis by trained pathologists are improving early-stage decision-making.

Evidence-based management of heart failure in clinical practice: a review of device-based therapy use

BACKGROUND

Heart failure is a growing health issue and is associated with significant mortality risk. Device therapy is efficacious in preventing sudden death in patients with heart failure; however, this evidence comes from rigorous clinical trials. It is unclear how device therapy is utilized in 'real-world' practice. The primary objective was to characterize patterns of device use in patients with heart failure at risk of sudden death and to identify barriers to guideline-driven prescription of implantable cardioverter-defibrillators.

METHODS

We report a cross-sectional study of patients attending general cardiology clinic over a 3-month period.

RESULTS

Of 1003 consecutive patients attending the cardiology clinic, 176 had heart failure. Of these, 66 were potentially eligible for device therapy, but only 16 of these had actually undergone device implantation. Potentially eligible non-recipients were older (P < 0.001), more likely to have ischaemic cardiomyopathy (P= 0.002), less likely to be prescribed spironolactone (P= 0.005) or warfarin (P= 0.02), and less likely to have a widened QRS > 120 ms (P= 0.005). There was a high prevalence of underuse of evidence-based pharmacotherapies among patients with heart failure.

CONCLUSION

There is substantial underuse of device therapy in patients with heart failure. Strikingly, whereas patients with symptoms of heart failure were more likely to receive a device, those being managed for ischaemic heart disease were not. There is also a high prevalence of failure to prescribe evidence-based pharmacotherapy in a tertiary hospital general cardiology clinic. This may be explained in part by the lack of a patient database to record treatment contraindications and to alert clinicians to possible gaps in patient therapy.

Abstract 4160: Evaluating epithelial-to-mesenchymal transition (EMT) in the EL1-luc/EL1-SV40 T-antigen transgenic mouse model of pancreatic cancer

Epithelial-to-mesenchymal transition (EMT) is a biological function important in normal cellular processes such as embryonic development and wound healing. In cancer it is thought that the tumor cell machinery can re-activate these normal pathways resulting in more aggressive and invasive tumors. The loss of E-cadherin and the gain of vimentin are hallmarks which identify the process of EMT and have been shown to correlate with poor prognosis in multiple solid tumor types. While many preclinical models are utilized to evaluate mechanisms of tumorigenesis few in vivo models evaluating parameters of EMT have been described.

The EL1-luc/EL1-SV40 T-antigen transgenic mouse represents a model of pancreatic cancer whereby mice develop tissue specific, spontaneous and bioluminescent pancreatic tumors. To evaluate whether EMT occurs in the EL1-luc/EL1-SV40 T-antigen model in vivo, we collected primary pancreatic tissue from male mice between 10 and 21 weeks of age. The tissue was formalin fixed, paraffin embedded and then utilized for histopathological endpoints such as Hemotoxylin and Eosin staining as well as immunohistochemistry for markers known to be involved in EMT such as E-cadherin and vimentin. We found the tumors to express both markers and become very heterogeneous over time. In early tumors E-cadherin expression is membrane localized and very high. Over time there are areas of the tumors that have reduced or lost E-cadherin expression. Vimentin expression was highly variable but when present tended to be highly expressed. In many of the later stage tumors there was substantial heterogeneity reflected by the appearance of multiple cell types within a tumor. We utilized the Aperio (Aperio Technologies, Vista, CA) slide scanner and software system to evaluate serial sections of tumor samples and found that in some sections of the tumor E-cadherin is present and vimentin is absent, whereas in other areas of the tumor vimentin is present in the absence of E-cadherin. Additionally, we identified areas of the tumor that seem to be expressing both markers which suggests that the EL1-luc/EL1-SV40 T-antigen transgenic mouse may recapitulate many aspects of EMT observed in vivo, thus offering a model system to study the signaling and molecular changes necessary for this process during cancer progression.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4160.

HIV and Long QT syndrome--cause or coincidence

The Long QT syndrome is a disorder characterized by abnormalities of cardiac repolarisation, resulting in a propensity to polymorphic ventricular tachycardia (torsades de pointes) and sudden cardiac death. It remains unclear whether cardiac involvement with the HIV virus itself can cause QT prolongation. We report a case of a HIV infected young female presenting with recurrent syncope due to torsades de pointes.

Intracranial drug-delivery scaffolds: Biocompatibility evaluation of sucrose acetate isobutyrate gels

INTRODUCTION

Sucrose acetate isobutyrate (SAIB) is a water insoluble, biodegradable gel used for controlled-release oral and subcutaneous drug delivery. We investigated SAIB compatibility in the rat central nervous system (CNS) by implanting solutions of SAIB in adult and in neonatal brains.

METHODS

10-15 microL solutions of SAIB gels in 0-30% ethanol were injected into the cerebral cortex of adult Fischer 344 rats. Control animals were implanted with a 10 mg biodegradable poly anhydride copolymer of poly [bis (p-carboxyphenoxy) propane] anhydride and sebacic acid (PCPP:SA). Adult rats were evaluated for signs of pain and distress, including changes in posture, facial signs, and grooming behavior. 1-2 microL solutions of SAIB gels in 15% ethanol were injected into brains of 12-24 h-old rats. Neonatal rats were evaluated for survival. Adult and neonatal brains were examined by histopathology 3-48 days after implant.

RESULTS

Gel implants produced elliptical compression of cortical tissue, cell loss, and inflammation. Cell loss appeared to be confined to the implantation wound and associated neuronal fields. In adult rats, neurophil compression, inflammation, and cell loss appeared similar with the 10-mg PCPP:SA implants and the 10-mg SAIB implants. There was no clinical evidence of pain or distress from SAIB implants. 1-2 microL implants of SAIB-15% ethanol had no effect on survival of neonatal animals.

CONCLUSION

Brain implants of SAIB induce a mild to moderate inflammatory response and associated neuronal cell damage. The implants appeared to be biocompatible in adult and neonatal animals. These results suggest that further studies of SAIB as an injectable drug-delivery scaffold for CNS therapeutic agents are warranted.

Intravenous magnesium sulfate for acute termination of sustained monomorphic ventricular tachycardia associated with coronary artery disease

The efficacy of intravenous magnesium in terminating sustained monomorphic ventricular tachycardia was examined in this study. This therapy was found to be ineffective in aborting monomorphic ventricular tachycardia induced in the electrophysiology laboratory.

Arteether-induced brain injury in Macaca mulatta. I. The precerebellar nuclei: the lateral reticular nuclei, paramedian reticular nuclei, and perihypoglossal nuclei

Malaria poses a threat across several continents: Eurasia (Asia and parts of Eastern Europe), Africa, Central and South America. Bradley (1991) estimates human exposure at 2,073,000,000 with infection rates at 270,000,000, illnesses at 110,000,000, and deaths at 1,000,000. Significant mortality rates are attributed to infection by the parasite Plasmodium falciparum, with an estimated 90% among African children. A worldwide effort is ongoing to chemically and pharmacologically characterize a class of artemisinin compounds that might be promising antimalarial drugs. The U.S. Army is studying the efficacy and toxicity of several artemisinin semi-synthetic compounds: arteether, artemether, artelinic acid, and artesunate. The World Health Organization and the U.S. Army selected arteether for drug development and possible use in the emergency therapy of acute, severe malaria. Male Rhesus monkeys (Macaca mulatta) were administered different daily doses of arteether, or the vehicle alone (sesame oil), for a period of either 14 days, or 7 days. Neuropathological lesions were found in 14-day arteether treated monkeys in the precerebellar nuclei of the medulla oblongata, namely: (1) the lateral reticular nuclei (subnuclei magnocellularis, parvicellularis, and subtrigeminalis), (2) the paramedian reticular nuclei (subnuclei accessorius, dorsalis, and ventralis), and the perihypoglossal nuclei (n. intercalatus of Staderini, n. of Roller, n. prepositus hypoglossi). The data demonstrate that the simina meduallry precerebellar nuclei have a high degree of vulnerability when arteether is given for 14 days at dose levels between 8mg/kg per day and 24 mg/kg per day. The neurological consequences of this treatment regimen could profoundly impair posture, gait, and autonomic regulation, while eye movement disorders might also be anticipated.

Safety, immunogenicity, and protective efficacy of NYVAC-JEV and ALVAC-JEV recombinant Japanese encephalitis vaccines in rhesus monkeys

Two poxvirus-vectored vaccines for Japanese encephalitis (JE), NYVAC-JEV and ALVAC-JEV, were evaluated in rhesus monkeys for safety, immunogenicity, and protective efficacy. The vaccines were given to four monkeys each on study days 0 and 28 along with saline placebo on day 7. For controls, the licensed BIKEN JE vaccine and a saline placebo were given to other groups of four monkeys on days 0, 7, and 28. No systemic effects were observed. All injection site reactions were mild. All vaccines elicited appreciable JE-specific neutralizing antibody responses. However, a more rapid increase and higher peak level of antibody were seen in the BIKEN group as compared with the NYVAC-JEV and ALVAC-JEV groups. The peak neutralizing antibody level in the NYVAC-JEV group was higher than that of the ALVAC-JEV group. Antibody persisted in all four BIKEN recipients through 273 days of follow-up, whereas, the antibody level decreased to the threshold of detection in two NYVAC-JEV and all four ALVAC-JEV recipients by day 120. On day 273, all monkeys were given a booster dose. A rapid increase in neutralizing antibody was seen in all vaccine recipients by seven days. Two months after the booster dose, all monkeys were challenged intranasally with one 90% effective dose of JE virus. Four recipients of saline, three of ALVAC-JEV, one of NYVAC-JEV, and one of BIKEN experienced encephalitis. This study suggests that the NYVAC-JEV and ALVAC-JEV vaccines are safe and immunogenic in monkeys and that the NYVAC-JEV and BIKEN vaccines are effective in protecting monkeys from encephalitis.

An intranasal challenge model for testing Japanese encephalitis vaccines in rhesus monkeys

Placebo-controlled field efficacy trials of new Japanese encephalitis (JE) vaccines may be impractical. Therefore, an animal model to evaluate efficacy of candidate JE vaccines is sought. Previous work has shown that exposure of monkeys to JE virus (JEV) via the intranasal route results in encephalitis. Here we report the further development of this model and the availability of titered virus stocks to assess the protective efficacy of JE vaccines. To determine the effective dose of our JE challenge virus, dilutions of a stock JEV (KE-93 isolate) were inoculated into four groups of three rhesus monkeys. A dose-dependent response was observed and the 50% effective dose (ED50) was determined to be 6.0 x 10(7) plaque forming units (pfu). Among animals that developed encephalitis, clinical signs occurred 9-14 days postinoculation. Infection with JEV was confirmed by detection of JEV in nervous tissues and IgM to JEV in the cerebrospinal fluid. Viremia with JEV was also detected intermittently throughout infection. Validation of the model was performed using a known effective JE vaccine and saline control. One ED90 of virus (2.0 x 10(9) pfu) was used as a challenge dose. Four of four animals that received saline control developed encephalitis while one of four monkeys administered the JE vaccine did so. This study demonstrates that the virus strain, route of inoculation, dose, and the outcome measure (encephalitis) are suitable for assessment of protective efficacy of candidate JE vaccines.

Production of lethal infection that resembles fatal human disease by intranasal inoculation of macaques with Japanese encephalitis virus

Twelve rhesus macaques (Macaca mulatta) challenged intranasally with a wild-type Japanese encephalitis virus (JEV) developed clinical signs 11-14 days later. Tissues from the cerebral cortex, cerebellum, brainstem, thalamus, meninges, and all levels of the spinal cord were stained for JEV antigen with hyperimmune mouse ascitic fluid and streptavidin-alkaline phosphatase; immunofluorescent staining was also done on frozen sections. Viral antigen was found in all cell layers of the cerebellum, the gray matter of the thalamus and brainstem, and the ventral horn of all levels of the spinal cord. Staining was limited to neurons and their processes. Histopathologic changes were limited to the nervous system and characterized by nonsuppurative meningoencephalitis. These results were comparable with those of previous studies done with human autopsy tissues. Intranasal inoculation of rhesus monkeys with JEV was effective in producing clinical disease comparable with natural disease in humans and may serve as a model to evaluate protective efficacy of candidate JEV vaccines.

Safety and Efficacy of DEET and Permethrin in the Prevention of Arthropod Attack

Many preventable diseases affecting troop strength are directly attributed to disease-carrying insects. The first line of defense against arthropod vectors is the use of personal protective measures. The concurrent application of DEET (N,N-diethyl-m-toluamide) repellent on the skin and permethrin [(3-phenoxy-phenyl)methyl(±)cis,trans-3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropane-carboxylate] insecticide on the battle dress uniform, while the uniform is worn properly, is a personal protective strategy officially known as the DOD Insect Repellent System. It is important for troop commanders and field leaders to enforce the use of personal protective measures to prevent insect-borne infectious diseases and to ensure troop and soldier readiness. DEET is a safe and effective repellent. Permethrin is a synthetic pyrethroid insecticide and repellent. Used in conjunction with proper clothing and other personal protective equipment, these repellents provide the best known protection available and are critical in minimizing the occupational health threat of arthropod-borne diseases to troops in the field.

Safety and efficacy of DEET and permethrin in the prevention of arthropod attack

Many preventable diseases affecting troop strength are directly attributed to disease-carrying insects. The first line of defense against arthropod vectors is the use of personal protective measures. The concurrent application of DEET (N,N-diethyl-m-toluamide) repellent on the skin and permethrin [(3-phenoxy-phenyl)methyl(+/-)cis,trans-3-(2,2-dichloroethenyl)-2, 2- dimethylcyclopropane-carboxylate] insecticide on the battle dress uniform, while the uniform is worn properly, is a personal protective strategy officially known as the DOD Insect Repellent System. It is important for troop commanders and field leaders to enforce the use of personal protective measures to prevent insect-borne infectious diseases and to ensure troop and soldier readiness. DEET is a safe and effective repellent. Permethrin is a synthetic pyrethroid insecticide and repellent. Used in conjunction with proper clothing and other personal protective equipment, these repellents provide the best known protection available and are critical in minimizing the occupational health threat of arthropod-borne diseases to troops in the field.

Arteether: risks of two-week administration in Macaca mulatta

Male rhesus monkeys (Macaca mulatta) were administered daily doses of the antimalarial drug arteether. The 14-day treated group received either 24 mg/kg/day, 16 mg/kg/day, or 8 mg/kg/day. The seven-day treatment group received either 24 mg/kg/day or 8 mg/kg/day. All control cases in each group received the sesame oil vehicle alone. Neurologic signs were absent for animals in the seven and 14-day treatment groups except for one monkey which showed diffuse piloerection on day 14, and another monkey receiving 24 mg/kg/day for seven days showed mild lethargy after the fourth day. Mild, sporadic anorexia was noted in all animals by day 14, and a single animal showed diffuse piloerection on day 14. Surgical anesthesia preceded killing by exsanguination and was accompanied by perfusion fixation of the central nervous system. Brain sections were cut and then stained for study by light microscopy. Evidence of neuronal pathology, both descriptive and numerical, was collected. The neuroanatomic and neuropathologic findings demonstrated that arteether produced extensive brainstem injury when administered for 14 days. The magnitude of brainstem neurotoxicity was dose-dependent, where injury was greatest at the 24 mg/kg/day dose level, less at the 16 mg/kg/day dose level, and least at the 8 mg/kg/day dose level. Arteether induced multiple systems injury to brainstem nuclei of 1) the reticular formation (cranial and caudal pontine nuclei, and medullary gigantocellular and paragigantocellular nuclei); 2) the vestibular system (medial, descending, superior, and lateral nuclei); and 3) the auditory system (superior olivary nuclear complex and trapezoid nuclear complex). The vestibular nuclei and the reticular formation were most severely injured, with the auditory system affected less. The cranial nerve nuclei (somatic and splanchnic) appeared to escape damage, with the exception of the abducens nerve nucleus. The same brainstem nuclear groups of seven-day treated monkeys appeared normal. The statistical data are concordant with the descriptive data in demonstrating neurotoxic effects. In summary, no neurologic deficits were detected in any of the vehicle control monkeys (14-day and seven-day cases). Monkeys in the 14-day treatment group were free of clinical neurologic signs throughout the first week. At day 14, fine horizontal nystagmus was seen in one monkey, and another monkey exhibited diffuse piloerection. Monkeys in the seven-day treatment group were free of clinical neurologic signs except for one case. This monkey was treated with 24/mg/kg/day of arteether and exhibited lethargy after the fourth day. These indications of dysfunction arose too late to be practical indicators of neurotoxicity.

Experimental infection of the laboratory rat with the hepatitis E virus

To confirm an earlier report that laboratory rats are susceptible to infection with the hepatitis E virus (HEV), we inoculated 27 Wistar rats intravenously with a suspension of a human stool known to contain infectious HEV. Stool, sera, and various tissues were collected from three rats each on days 0 (preinoculation) and 4, 7, 11, 14, 18, 21, 25, 28, and 35 postinoculation. Stool and sera specimens were examined by reverse transcription-polymerase chain reaction for the presence of HEV genomic sequences. Tissues were examined by light microscopy for detection of histopathological changes and by direct immunofluorescence for detection of HEV antigens. We detected HEV RNA in stools on day 7 in all three animals and in serum intermittently between days 4 and 35. We found HEV antigens in liver, peripheral blood mononuclear cells, spleen, mesenteric lymph nodes, and small intestine. We detected histopathology attributable to the inoculum in liver, spleen, and lymph nodes. The results confirm that HEV can replicate in laboratory rats and suggest new tissue sites for HEV replication.

Pathogenesis of hepatitis A in orally inoculated owl monkeys (Aotus trivirgatus)

The pathogenesis of hepatitis A virus (HAV) infection was studied in owl monkeys following oral administration of the wild-type HM-175 strain of HAV. Stools were collected daily and blood and pharyngeal swabs twice weekly for viral isolation, and animals were necropsied at various intervals after inoculation. Organs were examined for the presence of virus by isolation in cell culture and for viral antigens by immunofluorescence. Monkeys excreted HAV in the stools for 1-4 days after inoculation, presumably due to the residual unabsorbed inoculum. No virus was found in stools for the next 2-3 days. HAV re-appeared on days 4-7 and then persisted through day 39. Viremia occurred on the 10th day and continued until day 35. Virus was isolated occasionally from throat swabs 1 or 2 weeks after it was detected in stools and blood, and there was no evidence that HAV replicated in the pharyngeal tissues. Animals acquired anti-HAV antibody by the 4th week, and alanine aminotransferase (ALT) was elevated 5-5.5 weeks after inoculation. HAV was isolated from liver 5 days after inoculation; however, viral antigens were first detected in Kupffer cells of the liver at 14 days and in hepatocytes at 21 days. HAV antigen was detected in epithelial cells of the intestinal crypts and in the cells of the lamina propria of the small intestine 3 days postinoculation and thereafter until the 5th week, suggesting that these cells might represent an additional site of HAV replication.

Acute toxicity of cyclohexylmethylphosphonofluoridate (CMPF) in rhesus monkeys: serum biochemical and hematologic changes

Changes in serum biochemical and hematological parameters were studied in 20 male rhesus monkeys following acute poisoning by the organophosphate nerve agent cyclohexylmethylphosphonofluoridate (CMPF or GF). Animals were challenged with 5 x LD50 GF (233 micrograms/kg, IM) following pretreatment with pyridostigmine (0.3-0.7 mg/kg per 24 h) and treated with atropine (0.4 mg/kg, IM) and either 2-PAM (25.7 mg/kg, IM) or H16 (37.8 mg/kg, IM) at the onset of clinical signs or at 1 min after exposure. Muscle fasciculations, tremors, or convulsions occurred in 19 of 20 animals. Serum biochemical and hematologic parameters were analyzed 2 days and 7 days after exposure and compared to pre-exposure baseline values. Significant increases in creatine kinase (CK), lactate dehydrogenase (LD), aspartate transaminase (AST), alanine transaminase (ALT) and potassium ion (K+), associated with damage to striated muscle and metabolic acidosis, occurred in both oxime-treated groups 2 days after exposure. Total protein, albumin, red blood cell (RBC) count, hemoglobin concentration (Hb) and hematocrit (Hct), were decreased in both oxime-treated groups at 7 days. The results demonstrate that animals exposed to a single high dose of GF and treated with standard therapy exhibit changes in serum biochemical and hematological indices directly and indirectly associated with their clinical presentations.

Comparing matching ability, spatial memory, and ideational fluency in boys and girls

The purpose of our study was to examine whether girls and boys show patterns of problem-solving ability similar to those attributed by Kimura in 1992 to women and men, respectively. Subjects were 28 girls and 24 boys, aged 5-11 years, who were tested individually on matching ability, spatial memory, and ideational fluency, tasks on which women reportedly outperform men. No significant gender differences in these problem-solving abilities were found. On ideational fluency, the youngest girls were seven times more likely than young boys to give whimsical responses, but older girls were then times less likely than older boys to give whimsical responses. These results suggest that the patterns of visuospatial problem-solving abilities that Kimura ascribed to women and men are not present in preadolescent girls and boys.

Efficacy of sotalol guided by programmed electrical stimulation for sustained ventricular arrhythmias secondary to coronary artery disease

Sotalol is a class III antiarrhythmic drug with additional beta-blocker activity that has been shown to be effective in supraventricular and ventricular arrhythmias. Its long-term efficacy for ventricular arrhythmias is not as well described. Patients with documented sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) who had their clinical arrhythmia inducible at baseline electrophysiologic study received sotalol 320 to 640 mg/day. Repeat programmed stimulation was performed after a minimum of 72 hours while receiving the final dose. Of 28 patients (25 men and 3 women) whose arrhythmias were inducible at baseline, 15 had their arrhythmias suppressed with sotalol. Sotalol had greater success in suppressing arrhythmias in those with VF (8 of 9, 89%) than in those with VT (7 of 19, 37%, p < 0.01). In patients with a history of coronary artery disease but no history of myocardial infarction the arrhythmia was suppressed in 7 of 8 (88%) compared with 8 of 20 (40%, p < 0.05) patients with a history of myocardial infarction. All 15 patients in whom ventricular arrhythmias were suppressed continued to take long-term sotalol, and at a follow-up of 10.3 +/- 6.4 months none has had arrhythmia recurrence. Thus, sotalol is an effective drug for the suppression of ventricular arrhythmias as judged by programmed electrical stimulation. It appears to be more effective in patients in whom the clinical arrhythmia is VF rather than VT.

Enhancement of tissue plasminogen activator-induced fibrinolysis by activated protein C in endotoxin-treated rabbits

Endotoxin-treated rabbits produce high levels of plasminogen activator inhibitor-1 (PAI-1), which inhibits fibrinolysis by neutralizing endogenous tissue-type plasminogen activator (t-PA). These animals will develop renal fibrin deposition when infused with ancrod, an enzyme that acts directly on fibrinogen. In normal rabbits with an intact fibrinolytic system, ancrod induces hypofibrinogenemia without fibrin deposition. Rabbit PAI-1 activity can be neutralized by recombinant human t-PA or by bovine activated protein C. The present study determined the efficacy of these two agents used alone or in combination in neutralizing increased PAI-1 activity and in preventing renal fibrin deposition in a rabbit model. Male New Zealand rabbits first received intravenous endotoxin to increase PAI-1 activity. Ancrod was infused intravenously during hour 4 to 5, and the kidneys were examined at hour 5.5. Renal fibrin deposition occurred in 100% (6 out of 6) of the endotoxin-treated rabbits that received ancrod; this was reduced to 14% (1 out of 7) for rabbits receiving t-PA (170 micrograms/kg) before and during the ancrod infusion. Fibrin deposition occurred in only 12% (1 out of 8) of the rabbits that received a 10-fold lower dose of t-PA (17 micrograms/kg) combined with activated protein C (1 mg/kg) before and during the ancrod. Activated protein C at this dose completely neutralized plasma PAI-1 activity. However, low-dose t-PA and activated protein C did not prevent fibrin deposition when used as single agents, with fibrin deposition occurring in 75% and 100% of rabbits, respectively. The data indicate that activated protein C can neutralize plasma PAI-1 activity in vivo.(ABSTRACT TRUNCATED AT 250 WORDS)

Cryofibrinogenaemia: a case report

A case of chronic acral ulceration is described in a 54-year-old man with cryofibrinogenaemia. Initial management with prednisolone and azathioprine was unsuccessful in controlling the disease. Introduction of a programme of plasmapheresis in addition to treatment with cyclophosphamide and prednisolone has brought about marked improvement.

Peripheral vascular pathophysiology of Plasmodium berghei infection: a comparative study in the cheek pouch and brain of the golden hamster

Four- to six-week-old hamsters were infected with 1.5 X 10(7) Plasmodium berghei-parasitized hamster red blood cells by intraperitoneal injection. Cheek pouch circulation was observed microscopically in the anesthetized animal; the brain and contralateral pouch were collected for histopathologic examination on days 3-12 post-challenge. Cheek pouch vascular lesions, observed in vivo, appear to involve three phenomena; early (beginning 3-4 days) adhesion of pigment-laden mononuclear cells to endothelium within venous vessels and loss of function of the small capillaries supplying the skeletal muscle fibers and, later (6-9 days), the apparent attraction of erythrocytes to venular and venous endothelium and to adherent monocytes. The aggregation of formed elements on endothelial walls leads to progressive occlusion of venules and small veins and contributes to the observed disruption of flow through capillary networks. Histopathology of the brain and pouch shows vascular changes similar to those seen in vivo; in addition, multifocal hemorrhages are seen commonly in the brain and occasionally in the pouch on postmortem. In severe disease, evidence of cerebral edema is seen in the brain. The data suggest that failure of capillary flow and disruption of venous outflow tracts by cell aggregates are central to vascular failure in both the cheek pouch and brain of the P. berghei infected hamster. This hamster model of human cerebral malaria allows the in vivo observation, still and video photomicrography, and manipulation of the peripheral vascular pathogenesis of a disease process similar to that seen in humans.

Plasminogen activator inhibitor: a regulator of ancrod-induced fibrin deposition in rabbits

Plasma levels of a fast-acting plasminogen activator inhibitor (PAI), which neutralizes both tissue plasminogen activator (t-PA) and urokinase, are markedly increased in endotoxin-treated rabbits. The ability of this inhibitor to prevent the fibrinolysis that occurs after a thrombogenic stimulus was investigated in a rabbit model. Normal and endotoxin-treated male New Zealand rabbits were infused with ancrod, an enzyme that causes noncrosslinked fibrin formation in vivo. Ancrod stimulated t-PA activity by 90% in normal rabbits and caused hypofibrinogenemia but did not increase PAI levels or induce fibrin deposition in target organs. Rabbits injected with endotoxin (10 micrograms/kg) showed an increase in PAI from less than 1 to 32 U/mL 4 hours later. When ancrod was infused at this time, 90% of the rabbits developed renal fibrin thrombi. Fibrin deposition was recorded in 40% of the rabbits that received a lower dose of endotoxin (1.0 microgram/kg) and had a PAI level of 14 U/ml at the time of ancrod infusion 4 hours later. Fibrin deposition did not occur in the endotoxin-treated rabbits that received normal saline. These data suggest that high levels of PAI inhibit fibrinolysis in vivo, thereby promoting fibrin clot deposition following a thrombogenic stimulus.