Embelin and levodopa combination therapy for improved Parkinson's disease treatment

Parkinson’s disease (PD), a progressive neurodegenerative disorder, affects dopaminergic neurons. Oxidative stress and gut damage play critical roles in PD pathogenesis. Inhibition of oxidative stress and gut damage can prevent neuronal death and delay PD progression. The objective of this study was to evaluate the therapeutic effect of embelin or the combination with levodopa (LD) in a rotenone-induced PD mouse model. At the end of experimentation, the mice were sacrificed and the midbrain was used to evaluate various biochemical parameters, such as nitric oxide, peroxynitrite, urea, and lipid peroxidation. In the substantia nigra (midbrain), tyrosine hydroxylase (TH) expression was examined by immunohistochemistry, and Nurr1 expression was evaluated by western blotting. Gut histopathology was evaluated on tissue sections stained with hematoxylin and eosin. In silico molecular docking studies of embelin and α-synuclein (α-syn) fibrils were also performed. Embelin alone or in combination with LD ameliorated oxidative stress and gut damage. TH and Nurr1 protein levels were also significantly restored. Docking studies confirmed the affinity of embelin toward α-syn. Taken together, embelin could be a promising drug for the treatment of PD, especially when combined with LD.

Activation of a cryptic 5' splice site reverses the impact of pathogenic splice site mutations in the spinal muscular atrophy gene

Spinal muscular atrophy (SMA) is caused by deletions or mutations of the Survival Motor Neuron 1 (SMN1) gene coupled with predominant skipping of SMN2 exon 7. The only approved SMA treatment is an antisense oligonucleotide that targets the intronic splicing silencer N1 (ISS-N1), located downstream of the 5' splice site (5'ss) of exon 7. Here, we describe a novel approach to exon 7 splicing modulation through activation of a cryptic 5'ss (Cr1). We discovered the activation of Cr1 in transcripts derived from SMN1 that carries a pathogenic G-to-C mutation at the first position (G1C) of intron 7. We show that Cr1-activating engineered U1 snRNAs (eU1s) have the unique ability to reprogram pre-mRNA splicing and restore exon 7 inclusion in SMN1 carrying a broad spectrum of pathogenic mutations at both the 3'ss and 5'ss of the exon 7. Employing a splicing-coupled translation reporter, we demonstrate that mRNAs generated by an eU1-induced activation of Cr1 produce full-length SMN. Our findings underscore a wider role for U1 snRNP in splicing regulation and reveal a novel approach for the restoration of SMN exon 7 inclusion for a potential therapy of SMA.

TIA1 is a gender-specific disease modifier of a mild mouse model of spinal muscular atrophy

Spinal muscular atrophy (SMA) is caused by deletions or mutations of Survival Motor Neuron 1 (SMN1) gene. The nearly identical SMN2 cannot compensate for SMN1 loss due to exon 7 skipping. The allele C (C ^+/+) mouse recapitulates a mild SMA-like phenotype and offers an ideal system to monitor the role of disease-modifying factors over a long time. T-cell-restricted intracellular antigen 1 (TIA1) regulates SMN exon 7 splicing. TIA1 is reported to be downregulated in obese patients, although it is not known if the effect is gender-specific. We show that female Tia1-knockout (Tia1 ^-/-) mice gain significant body weight (BW) during early postnatal development. We next examined the effect of Tia1 deletion in novel C ^+/+/Tia1 ^-/- mice. Underscoring the opposing effects of Tia1 deletion and low SMN level on BW gain, both C ^+/+ and C ^+/+/Tia1 ^-/- females showed similar BW gain trajectory at all time points during our study. We observed early tail necrosis in C ^+/+/Tia1 ^-/- females but not in males. We show enhanced impairment of male reproductive organ development and exacerbation of the C ^+/+/Tia1 ^-/- testis transcriptome. Our findings implicate a protein factor as a gender-specific modifier of a mild mouse model of SMA.

How the discovery of ISS-N1 led to the first medical therapy for spinal muscular atrophy

Spinal muscular atrophy (SMA), a prominent genetic disease of infant mortality, is caused by low levels of survival motor neuron (SMN) protein owing to deletions or mutations of the SMN1 gene. SMN2, a nearly identical copy of SMN1 present in humans, cannot compensate for the loss of SMN1 because of predominant skipping of exon 7 during pre-mRNA splicing. With the recent US Food and Drug Administration approval of nusinersen (Spinraza), the potential for correction of SMN2 exon 7 splicing as an SMA therapy has been affirmed. Nusinersen is an antisense oligonucleotide that targets intronic splicing silencer N1 (ISS-N1) discovered in 2004 at the University of Massachusetts Medical School. ISS-N1 has emerged as the model target for testing the therapeutic efficacy of antisense oligonucleotides using different chemistries as well as different mouse models of SMA. Here, we provide a historical account of events that led to the discovery of ISS-N1 and describe the impact of independent validations that raised the profile of ISS-N1 as one of the most potent antisense targets for the treatment of a genetic disease. Recent approval of nusinersen provides a much-needed boost for antisense technology that is just beginning to realize its potential. Beyond treating SMA, the ISS-N1 target offers myriad potentials for perfecting various aspects of the nucleic-acid-based technology for the amelioration of the countless number of pathological conditions.

Diverse role of survival motor neuron protein

The multifunctional Survival Motor Neuron (SMN) protein is required for the survival of all organisms of the animal kingdom. SMN impacts various aspects of RNA metabolism through the formation and/or interaction with ribonucleoprotein (RNP) complexes. SMN regulates biogenesis of small nuclear RNPs, small nucleolar RNPs, small Cajal body-associated RNPs, signal recognition particles and telomerase. SMN also plays an important role in DNA repair, transcription, pre-mRNA splicing, histone mRNA processing, translation, selenoprotein synthesis, macromolecular trafficking, stress granule formation, cell signaling and cytoskeleton maintenance. The tissue-specific requirement of SMN is dictated by the variety and the abundance of its interacting partners. Reduced expression of SMN causes spinal muscular atrophy (SMA), a leading genetic cause of infant mortality. SMA displays a broad spectrum ranging from embryonic lethality to an adult onset. Aberrant expression and/or localization of SMN has also been associated with male infertility, inclusion body myositis, amyotrophic lateral sclerosis and osteoarthritis. This review provides a summary of various SMN functions with implications to a better understanding of SMA and other pathological conditions.

Severe impairment of male reproductive organ development in a low SMN expressing mouse model of spinal muscular atrophy

Spinal muscular atrophy (SMA) is caused by low levels of survival motor neuron (SMN), a multifunctional protein essential for higher eukaryotes. While SMN is one of the most scrutinized proteins associated with neurodegeneration, its gender-specific role in vertebrates remains unknown. We utilized a mild SMA model (C/C model) to examine the impact of low SMN on growth and development of mammalian sex organs. We show impaired testis development, degenerated seminiferous tubules, reduced sperm count and low fertility in C/C males, but no overt sex organ phenotype in C/C females. Underscoring an increased requirement for SMN expression, wild type testis showed extremely high levels of SMN protein compared to other tissues. Our results revealed severe perturbations in pathways critical to C/C male reproductive organ development and function, including steroid biosynthesis, apoptosis, and spermatogenesis. Consistent with enhanced apoptosis in seminiferous tubules of C/C testes, we recorded a drastic increase in cells with DNA fragmentation. SMN was expressed at high levels in adult C/C testis due to an adult-specific splicing switch, but could not compensate for low levels during early testicular development. Our findings uncover novel hallmarks of SMA disease progression and link SMN to general male infertility.

Vitamin D in clinically isolated syndrome: evidence for possible neuroprotection

BACKGROUND AND PURPOSE

Vitamin D status has been associated with inflammatory activity in multiple sclerosis (MS), but it is not known if it is associated with gray matter volume, the loss of which predicts long-term disability in MS. The association of vitamin D levels with brain volume measures and inflammatory activity in patients with clinically isolated syndrome (CIS) was investigated.

METHODS

In the phase 2 CIS trial of atorvastatin, 25-hydroxyvitamin D levels were evaluated for their age-adjusted associations with normalized gray matter and brain parenchymal volumes on brain magnetic resonance imaging (MRI). The relationships between 25-hydroxyvitamin D levels and clinical and MRI measures of inflammatory activity were also assessed.

RESULTS

In 65 patients in this substudy, each 25 nmol/l higher 25-hydroxyvitamin D level was associated with 7.8 ml higher gray matter volume (95% confidence interval 1.0, 14.6, P = 0.025). There was a tendency for an inverse association of average 25-hydroxyvitamin D levels and the composite end-point of ≥3 new brain T2 lesions or ≥1 relapse within a year (odds ratio per 25 nmol/l higher 25-hydroxyvitamin D level 0.66, 95% confidence interval 0.41, 1.08, P = 0.096).

CONCLUSIONS

Vitamin D status may impact neurodegeneration after CIS, although these results should be replicated in a second study. If confirmed in clinical trials, vitamin D supplementation may reduce long-term disability.

Hippocampal administration of chondroitinase ABC increases plaque-adjacent synaptic marker and diminishes amyloid burden in aged APPswe/PS1dE9 mice

Introduction

Substantial data has shown that the lectican group of chondroitin sulfate proteoglycans are involved in inhibition of axonal plasticity in response to injury in the central nervous system. Increasing evidence indicates that lecticans may also play a role in synaptic plasticity related to memory, especially associated with aging. A recent study has shown that lectican expression is elevated at a young age in the APPswe/PS1dE9 mouse model and Alzheimer’s disease (AD) and hippocampal treatment with chondroitinase ABC reversed a loss of contextual fear memory and restored long-term potentiation. The purpose of this study was to examine the presence of a synaptic lectican in AD tissue, determine if amyloid-β (Aβ) binds to lecticans purified from brain tissue, and examine how treatment of the same AD model with chondroitinase ABC would influence plaque burden and the density of the synaptic marker synaptophysin around plaques.

Results

In human superior frontal gyrus, levels of the brain-specific lectican, brevican, were significantly elevated in AD compared to non-cognitively impaired subjects, with a trend toward an increase in tissue from subjects with mild cognitive impairment. In vitro immunoprecipitation studies showed that brevican binds to oligomeric and fibrillar Aβ1-42, and less so to monomeric Aβ1-42. Intrahippocampal injection of 15 months APPswe/PS1dE9 mice with chondroitinase ABC resulted in a reduction of Aβ burden in the stratum lacunosum moleculare and a reversal of the loss of synaptic density surrounding plaques in the same region.

Conclusions

It is possible that lecticans, particularly brevican, inhibit synaptic plasticity in this model of AD. Since the hippocampus undergoes changes in synaptic plasticity early in the disease process, it could be possible that removal of lecticans or inhibition of their signaling pathways could prolong plasticity in patients early in the disease process, and delay cognitive decline of AD progression.

Electronic supplementary material

The online version of this article (doi:10.1186/s40478-015-0233-z) contains supplementary material, which is available to authorized users.

Past, present, and future for biologic intervention in atopic dermatitis

Atopic dermatitis (AD) is a debilitating disease that significantly alters the quality of life for one in four children and one in 10 adults. Current management of AD utilizes combinations of treatments to symptomatically alleviate disease by suppressing the inflammatory response and restoring barrier function in the skin, reducing disease exacerbation and flare, and preventing secondary skin infections. Resolution is temporary and long-term usage of these treatments can be associated with significant side-effects. Antibody therapies previously approved for inflammatory diseases have been opportunistically evaluated in patients with atopic dermatitis; however, they often failed to demonstrate a significant clinical benefit. Monoclonal antibodies currently in development offer hope to those individuals suffering from the disease by specifically targeting immune and molecular pathways important for the pathogenesis of atopic dermatitis. Here, we review the underlying biological pathways and the state of the art in therapeutics in AD.

ADAMTS expression and function in central nervous system injury and disorders

The components of the adult extracellular matrix in the central nervous system form a lattice-like structure that is deposited as perineuronal nets, around axon initial segments and as synapse-associated matrix. An abundant component of this matrix is the lecticans, chondroitin sulfate-bearing proteoglycans that are the major substrate for several members of the ADAMTSs (a disintegrin and metalloproteinase with thrombospondin motifs) family. Since lecticans are key regulators of neural plasticity, ADAMTS cleavage of lecticans would likely also contribute to neuroplasticity. Indeed, many studies have examined the neuroplastic contribution of the ADAMTSs to damage and recovery after injury and in central nervous system disease. Much of this data supports a role for the ADAMTSs in recovery and repair following spinal cord injury by stimulating axonal outgrowth after degradation of a glial scar and improving synaptic plasticity following seizure-induced neural damage in the brain. The action of the ADAMTSs in chronic diseases of the central nervous system appears to be more complex and less well-defined. Increasing evidence indicates that lecticans participate in synaptic plasticity in neurodegenerative disease states. It will be interesting to examine how ADAMTS expression and action would affect the progression of these diseases.

Spinal muscular atrophy: an update on therapeutic progress

Humans have two nearly identical copies of survival motor neuron gene: SMN1 and SMN2. Deletion or mutation of SMN1 combined with the inability of SMN2 to compensate for the loss of SMN1 results in spinal muscular atrophy (SMA), a leading genetic cause of infant mortality. SMA affects 1 in ~6000 live births, a frequency much higher than in several genetic diseases. The major known defect of SMN2 is the predominant exon 7 skipping that leads to production of a truncated protein (SMNΔ7), which is unstable. Therefore, SMA has emerged as a model genetic disorder in which almost the entire disease population could be linked to the aberrant splicing of a single exon (i.e. SMN2 exon 7). Diverse treatment strategies aimed at improving the function of SMN2 have been envisioned. These strategies include, but are not limited to, manipulation of transcription, correction of aberrant splicing and stabilization of mRNA, SMN and SMNΔ7. This review summarizes up to date progress and promise of various in vivo studies reported for the treatment of SMA.

Antisense oligonucleotide mediated therapy of spinal muscular atrophy

Spinal muscular atrophy (SMA) is the leading genetic cause of infant mortality. SMA results from deletions or mutations of survival motor neuron 1 (SMN1), an essential gene. SMN2, a nearly identical copy, can compensate for SMN1 loss if SMN2 exon 7 skipping is prevented. Among the many cis-elements involved in the splicing regulation of SMN exon 7, intronic splicing silencer N1 (ISS-N1) has emerged as the most effective target for an antisense oligonucleotide (ASO)-mediated splicing correction of SMN2 exon 7. Blocking of ISS-N1 by an ASO has been shown to fully restore SMN2 exon 7 inclusion in SMA patient cells as well as in vivo. Here we review how ISS-N1 targeting ASOs that use different chemistries respond differently in the various SMA mouse models. We also compare other ASO-based strategies for therapeutic splicing correction in SMA. Given that substantial progress on ASO-based strategies to promote SMN2 exon 7 inclusion in SMA has been made, and that similar approaches in a growing number of genetic diseases are possible, this report has wide implications.

Canonical transient receptor channel 5 (TRPC5) and TRPC1/4 contribute to seizure and excitotoxicity by distinct cellular mechanisms

Seizures are the manifestation of highly synchronized burst firing of a large population of cortical neurons. Epileptiform bursts with an underlying plateau potential in neurons are a cellular correlate of seizures. Emerging evidence suggests that the plateau potential is mediated by neuronal canonical transient receptor potential (TRPC) channels composed of members of the TRPC1/4/5 subgroup. We previously showed that TRPC1/4 double-knockout (DKO) mice lack epileptiform bursting in lateral septal neurons and exhibit reduced seizure-induced neuronal cell death, but surprisingly have unaltered pilocarpine-induced seizures. Here, we report that TRPC5 knockout (KO) mice exhibit both significantly reduced seizures and minimal seizure-induced neuronal cell death in the hippocampus. Interestingly, epileptiform bursting induced by agonists for metabotropic glutamate receptors in the hippocampal CA1 area is unaltered in TRPC5 KO mice, but is abolished in TRPC1 KO and TRPC1/4 DKO mice. In contrast, long-term potentiation is greatly reduced in TRPC5 KO mice, but is normal in TRPC1 KO and TRPC1/4 DKO mice. The distinct changes from these knockouts suggest that TRPC5 and TRPC1/4 contribute to seizure and excitotoxicity by distinct cellular mechanisms. Furthermore, the reduced seizure and excitotoxicity and normal spatial learning exhibited in TRPC5 KO mice suggest that TRPC5 is a promising novel molecular target for new therapy.

Selective decline of synaptic protein levels in the frontal cortex of female mice deficient in the extracellular metalloproteinase ADAMTS1

The chondroitin sulfate-bearing proteoglycans, also known as lecticans, are a major component of the extracellular matrix (ECM) in the central nervous system and regulate neural plasticity. Growing evidence indicates that endogenous, extracellular metalloproteinases that cleave lecticans mediate neural plasticity by altering the structure of ECM aggregates. The bulk of this in vivo data examined the matrix metalloproteinases, but another metalloproteinase family that cleaves lecticans, a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS), modulates structural plasticity in vitro, although few in vivo studies have tested this concept. Thus, the purpose of this study was to examine the neurological phenotype of a mouse deficient in ADAMTS1. Adamts1 mRNA was absent in the ADAMTS1 null mouse frontal cortex, but there was no change in the abundance or proteolytic processing of the prominent lecticans brevican and versican V2. However, there was a marked increase in the perinatal lectican neurocan in juvenile ADAMTS1 null female frontal cortex. More prominently, there were declines in synaptic protein levels in the ADAMTS1 null female, but not male, frontal cortex beginning at postnatal day 28. These synaptic marker declines did not affect learning or memory in the adult female ADAMTS1 null mice when tested with the radial-arm water maze. These results indicate that in vivo Adamts1 knockout leads to sexual dimorphism in frontal cortex synaptic protein levels. Since changes in lectican abundance and proteolytic processing did not accompany the synaptic protein declines, ADAMTS1 may play a nonproteolytic role in regulating neural plasticity.

Lectican proteoglycans, their cleaving metalloproteinases, and plasticity in the central nervous system extracellular microenvironment

The extracellular matrix (ECM) in the central nervous system actively orchestrates and modulates changes in neural structure and function in response to experience, after injury, during disease, and with changes in neuronal activity. A component of the multi-protein, ECM aggregate in brain, the chondroitin sulfate (CS)-bearing proteoglycans (PGs) known as lecticans, inhibit neurite outgrowth, alter dendritic spine shape, elicit closure of critical period plasticity, and block target reinnervation and functional recovery after injury as the major component of a glial scar. While removal of the CS chains from lecticans with chondroitinase ABC improves plasticity, proteolytic cleavage of the lectican core protein may change the conformation of the matrix aggregate and also modulate neural plasticity. This review centers on the roles of the lecticans and the endogenous metalloproteinase families that proteolytically cleave lectican core proteins, the matrix metalloproteinases (MMPs) and a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTSs), in neural plasticity. These extracellular metalloproteinases modulate structural neural plasticity-including changes in neurite outgrowth and dendritic spine remodeling-and synaptic plasticity. Some of these actions have been demonstrated to occur via cleavage of the PG core protein. Other actions of the proteases include cleavage of non-matrix substrate proteins, whereas still other actions may occur directly at the cell surface without proteolytic cleavage. The data convincingly demonstrate that metalloproteinases modulate physiological and pathophysiological neural plasticity.

The association of lactate and vasopressor need for mortality prediction in survivors of cardiac arrest

BACKGROUND

Currently there are few tools available for clinicians to predict outcomes in cardiac arrest survivors. Our objective was to determine if the combination of simple clinical parameters (initial blood lactate and vasopressor use) can predict outcome in post-cardiac arrest patients.

METHODS

The design was a retrospective medical record review. The study was carried on in two urban, tertiary-care, university teaching hospitals. As for patients, inclusion criteria were: 1) age ≥18 years; 2) non-traumatic out-of-hospital cardiac arrest with return of spontaneous circulation; 3) lactic acid measured within one hour of return of circulation. No interventions was performed.

RESULTS

Patients were divided into groups based on two variables: 1) vasopressor status (receipt of vasopressors vs. no vasopressors); and 2) initial blood lactate (categories defined as lactate <5 mmol/L, lactate 5 to 10 mmol/L, lactate ≥10 mmol/L); 128 out-of-hospital cardiac arrest patients met study inclusion criteria. Overall mortality was 71% (95%CI 63-79%). Patients who received vasopressors had significantly higher mortality rates compared to patients who did not receive vasopressors (80% vs. 52%; P=0.002). A stepwise increase in mortality is associated with increasing lactate levels (39% lactate <5 mmol/L, 67% lactate 5 mmol/L to10 mmol/L, and 92% lactate ≥10 mmol/L; P<0.001). The AUC for our model was 0.82.

CONCLUSION

The combination of two clinical parameters, vasopressor need and lactic acid levels, is an accurate severity of illness classification system and can predict mortality in patients following out-of-hospital cardiac arrest. Prospective validation of these variables in post-cardiac arrest is needed.

Human factors in resuscitation: Lessons learned from simulator studies

Medical algorithms, technical skills, and repeated training are the classical cornerstones for successful cardiopulmonary resuscitation (CPR). Increasing evidence suggests that human factors, including team interaction, communication, and leadership, also influence the performance of CPR. Guidelines, however, do not yet include these human factors, partly because of the difficulties of their measurement in real-life cardiac arrest. Recently, clinical studies of cardiac arrest scenarios with high-fidelity video-assisted simulations have provided opportunities to better delineate the influence of human factors on resuscitation team performance. This review focuses on evidence from simulator studies that focus on human factors and their influence on the performance of resuscitation teams. Similar to studies in real patients, simulated cardiac arrest scenarios revealed many unnecessary interruptions of CPR as well as significant delays in defibrillation. These studies also showed that human factors play a major role in these shortcomings and that the medical performance depends on the quality of leadership and team-structuring. Moreover, simulated video-taped medical emergencies revealed that a substantial part of information transfer during communication is erroneous. Understanding the impact of human factors on the performance of a complex medical intervention like resuscitation requires detailed, second-by-second, analysis of factors involving the patient, resuscitative equipment such as the defibrillator, and all team members. Thus, high-fidelity simulator studies provide an important research method in this challenging field.

Abnormal post-translational and extracellular processing of brevican in plaque-bearing mice over-expressing APPsw

Aggregation of amyloid-beta (Abeta) in the forebrain of Alzheimer's disease (AD) subjects may disturb the molecular organization of the extracellular microenvironment that modulates neural and synaptic plasticity. Proteoglycans are major components of this extracellular environment. To test the hypothesis that Abeta, or another amyloid precursor protein (APP) dependent mechanism modifies the accumulation and/or turnover of extracellular proteoglycans, we examined whether the expression and processing of brevican, an abundant extracellular, chondroitin sulfate (CS)-bearing proteoglycan, were altered in brains of Abeta-depositing transgenic mice (APPsw - APP gene bearing the Swedish mutation) as a model of AD. The molecular size of CS chains attached to brevican was smaller in hippocampal tissue from APPsw mice bearing Abeta deposits compared to non-transgenic mice, likely because of changes in the CS chains. Also, the abundance of the major proteolytic fragment of brevican was markedly diminished in extracts from several telencephalic regions of APPsw mice compared to non-transgenic mice, yet these immunoreactive fragments appeared to accumulate adjacent to the plaque edge. These results suggest that Abeta or APP exert inhibitory effects on proteolytic cleavage mechanisms responsible for synthesis and turnover of proteoglycans. As proteoglycans stabilize synaptic structure and inhibit molecular plasticity, defective brevican processing observed in Abeta-bearing mice and potentially end-stage human AD, may contribute to deficient neural plasticity.

Utility of thrombocytopenia as a marker for heparin allergy in adult ED patients

INTRODUCTION

Up to 5% of patients who receive heparin develop heparin allergy (HA), manifested by the presence of heparin antibodies (HAb) and/or the clinical syndrome of heparin-induced thrombocytopenia. As many as 10% of patients with HA develop serious thrombotic complications when reexposed to heparin. Heparin is often given empirically to emergency department (ED) patients, some of whom have been recently hospitalized and are at risk for HA/heparin-induced thrombocytopenia. Emergency department physicians should have a rapid means of determining which patients are at risk for heparin sensitivity. The prevalence of HA among ED patients is unknown; most are asymptomatic and unaware, and there is no bedside test available.

OBJECTIVES

This study was designed to assess the prevalence of HA or thrombocytopenia in ED patients and to determine whether thrombocytopenia could serve as a useful marker for HA.

METHODS

This was a prospective, observational study, done during the spring of 2004 in an 80000 adult visit inner-city ED. A convenience sample of 115 adult patients undergoing venipuncture had a blood specimen analyzed for platelet count using standard laboratory methods. The same blood sample was tested for the presence of antiheparin antibodies using an enzyme-linked immunosorbent assay test.

RESULTS

Of 115 patients, 12 (10.4%; 95% CI, 6.1%-17.4%) had thrombocytopenia (platelets <150000). Six (5.2%; 95% CI, 2.5%-10.9%) had antiheparin antibodies. There was no overlap between the 2 groups of patients.

CONCLUSIONS

(1) Thrombocytopenia occurs in 10% of a sample of 115 adult ED patients undergoing venipuncture in an inner-city ED. (2) Heparin allergy was present in 5% of patients in the same cohort. (3) Thrombocytopenia is neither sensitive nor specific as a marker for HA in ED patients. Heparin-allergic patients are at risk if given heparin; a method of rapid detection of patients with HA should be identified.

Congestive heart failure and outpatient risk of venous thromboembolism: a retrospective, case-control study

Although CHF has been considered a risk factor for venous thromboembolism, this has not been directly studied. We hypothesized that congestive heart failure would increase the risk of venous thromboembolism in an outpatient population, and that this risk would increase as patients' ventricular function worsened. We conducted a case-control study to examine whether CHF due to left ventricular dysfunction was an independent risk factor for acute venous thromboembolism in outpatients, once established risk factors such as recent surgery and prior venous thromboembolism are taken into account. We reviewed 106 cases of DVT and 603 controls, admitted for diabetes mellitus or infection, matched for month of admission at a VA hospital. Assignment of a diagnosis of venous thromboembolism required a definitive test, as did classification as CHF. In a logistic regression model CHF was an independent predictor of venous thromboembolism. A second logistic regression model showed that the risk of venous thromboembolism increased as the ejection fraction (EF) decreased, with an EF < 20 associated with a venous thromboembolism OR of 38.3 (95% CI 9.6, 152.5). CHF is an independent risk factor for venous thromboembolism, and the risk increases markedly as the EF decreases. These results support the use of anticoagulation in selected patients with CHF.

Soluble tumor necrosis factor receptor type I enhances tumor development and persistence in vivo

Secretion of human soluble tumor necrosis factor receptor type I (sTNFRI) by the mouse fibrosarcoma cell line, L929, previously has been demonstrated to confer resistance to in vitro lysis by TNF and to LAK- and CTL-mediated cytolysis. These findings suggest that, in vivo, sTNFRI contributes to tumor survival by inhibiting these immunologic mechanisms. To evaluate this hypothesis, we compared the growth of sTNFRI-secreting L929 cells with that of the unmodified parental fibrosarcoma in an in vivo mouse transplantation model. Secretion of sTNFRI by L929 cells markedly enhanced their tumorigenicity and persistence in syngeneic recipients. This benefit was abrogated by sTNFRI-neutralizing antibodies induced by immunization prior to tumor challenge. These data demonstrate that sTNFRI directly influences tumor formation and persistence in vivo and suggest the selective removal and/or inactivation of sTNFRI as a promising new avenue for cancer immunotherapy.

Comparison of a maedi-visna virus CA-TM fusion protein ELISA with other assays for detecting sheep infected with North American ovine lentivirus strains

A maedi-visna virus CA-TM fusion protein ELISA (MVV ELISA) was evaluated for the detection of antibody in sheep infected with North American ovine lentivirus (OvLV). The results of the MVV ELISA were compared with other assays for OvLV antibody and with viral infection in an intensively studied group of 38 sheep with a high prevalence of OvLV infection and disease. The sensitivity, specificity, and concordance of assays for OvLV antibody (MVV ELISA, indirect ELISA, Western blot, and AGID), virus (virus isolation, PCR, antigen ELISA), and OvLV-induced disease in each animal were compared with OvLV infection status as defined by a positive result in two or more of the assays. Five sheep met the criteria for absence of OvLV infection. The sensitivity of the MVV ELISA in detecting OvLV infected sheep was 64%, whereas the sensitivity of the other three tests for antibody ranged from 85 to 94%. All the antibody assays were 100% specific in this group of animals. Of the assays for virus, the PCR test had the highest sensitivity and the best concordance with OvLV infection, but it also had the lowest specificity of any of the virus or antibody assays. Among the antibody tests, the concordance of the MVV ELISA compared most favorably with the AGID test for detecting OvLV-infected sheep. Analysis of serum samples from 28 lambs experimentally-infected with one of three North American strains of OvLV suggested that there were no significant strain differences detectable by antibody assay. Twenty virus-inoculated lambs were positive by both the MVV ELISA and the AGID test, five lambs were MVV ELISA negative and AGID test positive, and three lambs were MVV ELISA positive and AGID test negative. No pre-inoculation samples were positive by either assay. In a longitudinal study involving seven lambs, antibodies to OvLV were detected by AGID 3-5 weeks post-inoculation, but were not detected by MVV ELISA until 5-10 weeks post-inoculation. Among 128 naturally and experimentally-infected sheep that were seropositive in the AGID test, the overall sensitivity of the MVV ELISA was higher in the naturally infected sheep (84%) than in the experimentally infected sheep (69%). The data indicated that the MVV ELISA represents a less sensitive, but specific alternative for the detection of OvLV antibodies.

Analysis of sheep T-cell receptor beta-chain heterogeneity

We analyzed nucleotide and deduced amino acid sequence heterogeneity of sheep T-cell receptor beta-chain cDNAs isolated from an anchored-polymerase chain reaction library. Evaluation of 34 individual rearrangements has defined 18 new beta-chain variable region sequences which have been clustered into 13 families. Presumptive allelic polymorphisms of four of these variable regions have been defined, as well as ten distinct beta-chain joining region sequences. The present analysis indicates that sheep T-cell receptor beta-chains are composed of characteristic leader, variable, joining, and constant region sequences, and that imprecise joining and N-region addition contribute significantly to diversity in the third hypervariable region. Thus, it appears that sheep, like all other mammals studied to date, employ somatic rearrangement of multiple germline genes to create beta-chain heterogeneity. These findings have allowed us to estimate the diversity of the sheep T-cell receptor beta-chain variable region repertoire, and they provide information that will permit the evaluation of the role that specific T-cell populations play in naturally occurring and experimental diseases of sheep.

Multifaceted inhibition of anti-tumour immune mechanisms by soluble tumour necrosis factor receptor type I

Soluble tumour necrosis factor receptor type I (sTNFRI) is a potent inhibitor of TNF with the potential to suppress a variety of effector mechanisms important in tumour immunity. That sTNFRI influences tumour survival in vivo is suggested by results from human clinical trials of Ultrapheresis, an experimental extracorporeal treatment for cancer. While the considerable clinical benefit provided by Ultrapheresis is correlated with the removal of plasma sTNFRI, there is no direct evidence that sTNFRI inhibits immune mechanisms which mediate tumour cell elimination. To evaluate formally the ability of sTNFRI to inhibit these mechanisms, we have engineered sTNFRI production into the TNF-sensitive murine fibrosarcoma cell line, L929. Soluble TNFRI-secreting L929 cells display increased resistance to direct lysis by TNF, and to lysis by syngeneic lymphokine-activated killer cells and cytotoxic T cells. These findings confirm the suggestion that sTNFRI inhibits immunological mechanisms important in tumour cell eradication, and further support a role for sTNFRI in tumour survival in vivo. In addition, these observations suggest the development of methods for more specific removal and/or inactivation of sTNFRI as promising new avenues for cancer immunotherapy.

Neonatal appendectomy impairs mucosal immunity in rabbits

We compared the effects of neonatal appendectomy in rabbits on total Ig and antigen (Ag)-specific Ig levels in the serum and gut, and on plasma cell numbers in the small intestine in response to intraperitoneal (i.p.) and intraduodenal (i.d.) immunizations with ovalbumin (OVA). Animals were sacrificed after 9 weeks. Antibodies (Abs) in the duodenum were collected and quantified by enzyme-linked immunosorbent assay (ELISA) while plasma cells were quantified by double immunofluorescent staining. Appendectomy markedly reduced total intestinal IgA (P < 0.0006), IgM (P < 0.003), and IgG (P < 0.05) relative to controls, whereas total serum Ig levels were not lowered significantly. Moreover, appendectomy nearly ablated OVA-specific IgA (P < 0.007) in the gut and severely depleted OVA-specific IgG in the gut (P < 0.03) and serum (P < 0.007). The sharp decreases in total IgA and anti-OVA IgA were paralleled by decreases in total IgA+ plasma cells (P < 0.0005) and OVA-reactive IgA+ plasma cells (P < 0.05). These results support a major role of the rabbit appendix in seeding the intestinal lamina propria with plasma cell precursors, especially those producing IgA.

Homologies between T cell receptor junctional sequences unique to multiple sclerosis and T cells mediating experimental allergic encephalomyelitis

The selection of T cell clones with mutations in the hypoxanthine guanine phosphoribosyltransferase (hprt) gene has been used to isolate T cells reactive to myelin basic protein (MBP) in patients with multiple sclerosis (MS). These T cell clones are activated in vivo, and are not found in healthy individuals. The third complementarity determining regions (CDR3) of the T cell receptor (TCR) alpha and beta chains are the putative contact sites for peptide fragments of MBP bound in the groove of the HLA molecule. The TCR V gene usage and CDR3s of these MBP-reactive hprt-T cell clones are homologous to TCRs from other T cells relevant to MS, including T cells causing experimental allergic encephalomyelitis (EAE) and T cells found in brain lesions and in the cerebrospinal fluid (CSF) of MS patients. In vivo activated MBP-reactive T cells in MS patients may be critical in the pathogenesis of MS.

T cell receptors, immunoregulation, and autoimmunity

T cell receptor (TCR) peptide vaccines have proven useful in the prevention and treatment of autoimmune disease in animal models. Prospects for developing TCR peptide vaccines for human autoimmune disease are only now being explored. Preliminary indications provide cause for optimism that immunization with TCR peptides eventually will be a viable treatment option for autoimmune pathologies in humans. In the long term, development of this technology may permit reliable manipulation of T cell immunity, leading to treatments for autoimmunity, T lymphoproliferative disorders, and, in the broadest interpretation, any pathogenesis mediated by oligoclonal T cell populations.

Immunoregulation of autoimmune disease by vaccination with T cell receptor peptides

Restricted TCR gene usage in animal models of autoimmune disease has led to strategies for control of these diseases by targeting the idiotypic determinants within the TCR sequence. Rats can be rendered resistant to EAE by immunization with synthetic peptides representing sequences contained within the V beta, J alpha and VDJ beta regions of the TCR that are conserved among encephalitogenic T cells. We propose that the mechanism of immunoregulation thus produced results from the stimulation of an anticlonotypic response directed at endogenously synthesized TCR peptides presented by Class I MHC on the surface of the autoreactive T cell, and that this mechanism may be part of the natural immunoregulation of T cell responses. The experimental data demonstrate the utility of this therapeutic approach and its potential for treatment of any pathogenic condition mediated by specific, oligoclonal T cell populations.

Limited T-cell receptor beta-chain heterogeneity among interleukin 2 receptor-positive synovial T cells suggests a role for superantigen in rheumatoid arthritis

Rheumatoid arthritis (RA) is a disease affecting the synovial membranes of articulating joints that is thought to result from T-cell-mediated autoimmune phenomena. T cells responsible for the pathogenesis of RA are likely present in that fraction of synovial T cells that expresses the interleukin 2 receptor (IL-2R), one marker of T-cell activation. We report herein an analysis of T-cell receptor (TCR) beta-chain gene expression by IL-2R-positive synovial T cells. These T cells were isolated from uncultured synovial tissue specimens by using IL-2R-specific monoclonal antibodies and magnetic beads, and TCR beta-chain transcription was analyzed by PCR-catalyzed amplification using a panel of primers specific for the human TCR beta-chain variable region (V beta). Multiple V beta gene families were found to be transcribed in these patients samples; however, three gene families, V beta 3, V beta 14, and V beta 17, were found in a majority of the five synovial samples analyzed, suggesting that T cells bearing these V beta s had been selectively retained in the synovial microenvironment. In many instances, the V beta 3, V beta 14, or V beta 17 repertoires amplified from an individual patient were dominated by a single rearrangement, indicative of clonal expansion in the synovium and supportive of a role for these T cells in RA. Of note is a high sequence similarity between V beta 3, V beta 14, and V beta 17 polypeptides, particularly in the fourth complementarity-determining region (CDR). Given that binding sites for superantigens have been mapped to the CDR4s of TCR beta chains, the synovial localization of T cells bearing V beta s with significant CDR4 homology indicates that V beta-specific T-cell activation by superantigen may play a role in RA.

A myelin basic protein peptide is recognized by cytotoxic T cells in the context of four HLA-DR types associated with multiple sclerosis

We have examined previously the peptide specificity of the T cell response to myelin basic protein (MBP) in patients with multiple sclerosis (MS) and healthy controls, and demonstrated that an epitope spanning amino acids 87-106 was frequently recognized. Because this region is encephalitogenic in some experimental animals, it has been postulated that the response to the epitope may have relevance to MS. In this study, the fine specificity of this response is studied using four well-characterized, monospecific T cell lines from three MS patients and an identical twin of a patient. Each of the lines recognized a peptide with the same core sequence, amino acids 89-99, although the responses were affected to various degrees by truncations at the COOH- or NH2 terminal ends of the 87-106 epitope. Importantly, the epitope was recognized in conjunction with four different HLA-DR molecules. Also, the T cell receptor beta chain usage was heterogeneous, and each line expressed a different VDJ sequence. The four HLA-DR molecules restricting the response to this epitope have been shown to be overrepresented in MS populations in various geographic areas, suggesting that the response to this region of the MBP molecule may be relevant to the pathogenesis of MS. These findings may have important implications in designing therapeutic strategies for the disease.

Vaccination against experimental allergic encephalomyelitis with T cell receptor peptides

Experimental allergic encephalomyelitis (EAE) is an autoimmune disease of the central nervous system mediated by CD4+ T cells reactive with myelin basic protein (MBP). Rats were rendered resistant to the induction of EAE by vaccination with synthetic peptides corresponding to idiotypic determinants of the beta chain VDJ region and J alpha regions of the T cell receptor (TCR) that are conserved among encephalitogenic T cells. These findings demonstrate the utility of TCR peptide vaccination for modulating the activity of autoreactive T cells and represent a general therapeutic approach for T cell-mediated pathogenesis.

An extended HLA-D region haplotype associated with celiac disease

Celiac disease has one of the strongest associations with HLA (human leukocyte antigen) class II markers of the known HLA-linked diseases. This association is primarily with the class II serologic specificities HLA-DR3 and -DQw2. We previously described a restriction fragment length polymorphism (RFLP) characterized by the presence of a 4.0-kilobase Rsa I fragment derived from an HLA class II beta-chain gene, which distinguishes the class II HLA haplotype of celiac disease patients from those of many serologically matched controls. We now report the isolation of this beta-chain gene from a bacteriophage genomic library constructed from the DNA of a celiac disease patient. Based on restriction mapping and differential hybridization with class II cDNA and oligonucleotide probes, this gene was identified as one encoding an HLA-DP beta chain. This celiac disease-associated HLA-DP beta-chain gene was flanked by HLA-DP alpha-chain genes and, therefore, was probably in its normal chromosomal location. The HLA-DP alpha-chain genes of celiac disease patients also were studied by RFLP analysis; 84% of HLA-DR3, -DQw2 patients had a 16-kb Xba I fragment that was present in only 36% of HLA-DR3, -DQw2 controls. Moreover, 79% of these patients had both alpha- and beta-chain polymorphisms in contrast to 27% of controls. Thus, celiac disease is associated with a subset of HLA-DR3, -DQw2 haplotypes characterized by HLA-DP alpha- and beta-chain gene RFLPs. Within the celiac-disease patient population, the joint segregation of these HLA-DP genes with those encoding the serologic specificities HLA-DR3 and -DQw2 indicates: (i) that the class II HLA haplotype associated with celiac disease is extended throughout the entire HLA-D region, and (ii) that celiac-disease susceptibility genes may reside as far centromeric on this haplotype as the HLA-DP subregion.

Production of murine leukemia virus in the immunodeficient wasted mutant mouse is associated with the wst allele

The recessive mutation "wasted" (wst) is responsible for a neuroimmunological syndrome and premature death in homozygous wst/wst mice. In contrast, +/wst heterozygotes appear phenotypically normal. The present study assessed the production of endogenous murine leukemia virus (MuLV) in lymphoid organs of homozygous wasted (wst/wst), heterozygous wasted (+/wst) and control wild type (+/+) mice. Neither mutant nor control mice produced ecotropic MuLV. In contrast, lymphoid organs from wst/wst and +/wst mice produced endogenous xenotropic MuLV. MuLV production was not detectable in the same organs of +/+ control mice. +/wst heterozygotes produced xenotropic MuLV in the thymus, spleen and mesenteric lymph nodes but not in the bone marrow. Wst/wst mutants produced xenotropic MuLV, but only in the thymus. These findings demonstrate an association between the production of endogenous xenotropic MuLV and the wasted mutation.

Spurious DNA blot hybridization resulting from bacterial contamination of primary tissue preparations

We have observed, by Southern blot hybridization, numerous episomes in DNA prepared from tumors grown as athymic mouse xenografts. These extrachromosomal DNAs were present in multiple copies and existed as relaxed and supercoiled conformational isomers. The episomes were readily detected with pBR322 plasmid probes, but not with purified plasmid inserts. Subsequently, four species of bacteria were isolated from tumor xenografts, suggesting that the pBR322 related episomes which we observed were bacterial DNAs, copurified during the isolation of xenograft DNA. This finding illustrates a potential problem which may be encountered in blot hybridizations utilizing nucleic acids from primary tissue preparations.

Rapid identification of hybridization probes for chromosomal walking

The presence of repeated elements in restriction fragments used as hybridization probes for chromosomal walking poses a major obstacle to the success of this gene-cloning strategy. This report describes a simple and rapid means of identifying restriction fragments devoid of repeated sequences and therefore useful as hybridization probes for chromosomal walking. Restriction fragments derived from a genomic DNA clone are Southern blotted and hybridized to nick-translated total genomic [32P]DNA. Fragments of the genomic clone that contain high abundance sequences (i.e., repeated elements) hybridize strongly to their nick-translated counterparts, which, due to their high copy number, comprise a significant proportion of the total genomic DNA probe. Conversely, fragments containing single-copy or low-abundance sequences do not hybridize, as their nick-translated counterparts are poorly represented in the total genomic DNA probe. These latter fragments, by virtue of their low-abundance sequences, are well suited as probes for chromosomal walking. Ensuring the absence of repeated elements in restriction fragments prior to their purification and utilization as chromosomal walking probes results in marked savings of time, effort and materials.

An HLA-D region restriction fragment length polymorphism associated with celiac disease

This study is the first to describe a molecular marker that distinguishes the celiac disease HLA-D region haplotype from a serologically identical haplotype in unaffected controls. Using a DQ beta chain cDNA probe and the restriction endonuclease Rsa I, we have detected a polymorphic 4.0 kb fragment which, in DQw2 individuals, is associated with a 40-fold increased relative risk of developing celiac disease. This finding should permit the identification of the celiac disease susceptibility gene(s) in the HLA-D region and facilitate a more precise dissection of the molecular and immunogenetic mechanisms involved in the pathogenesis of that disease.

Toxicity of ricin, diphtheria toxin and alpha-Amanitin for Acanthamoeba castellanii (1983)

Selective cytotoxic agents, highly specific antibody coupled to potent toxin molecules, could, theoretically, be useful in the treatment of protozoan infections. To examine this possibility we began to synthesize immunotoxins for a model protozoan system, Acanthamoeba castellanii. We report here the selection of a suitable toxic moiety for this system. alpha-Amanitin was toxic for the amoeba, effecting a 50% decrease in in vivo protein synthesis at approximately 20 microM. However, the chemical modification of alpha-amanitin necessary for its covalent attachment to antibody molecules reduced A. castellanii toxicity to the extent that alpha-amanitin is unsuitable as a toxic moiety in the synthesis of A. castellanii immunotoxins. Ricin and diphtheria toxin were non-toxic for the amoeba. In addition, A. castellanii cell-free protein biosynthesis, unlike that of any other eukaryotic system examined to date, was resistant to inhibition by ricin A chain. However, diphtheria toxin A chain inhibited A. castellanii cell-free protein synthesis by 50% at 2.5 nM. The inhibition of diphtheria toxin was NAD+ dependent, suggesting that ADP-ribosylation of EF-2 could be the cause of the inhibition as it is in mammalian cell lines. The toxicity of diphtheria toxin A chain is sufficient for its use in the synthesis of immunotoxins for A. castellanii.