Modifying chromatin and concepts of cancer

A wave of biochemical and genetic progress has identified proteins that influence transcription by modifying chromatin. Many such factors are broadly conserved and, strikingly, occur in human diseases as partners in chromosomal translocations. Understanding the function of these factors will be key to defining mechanisms of transcriptional regulation and understanding cancers linked to aberrant chromatin modification.

The effect of membrane permeability on ESRD: design of a prospective randomised multicentre trial

The different permeability of high-flux and low-flux dialysis membranes results in different removal capacity, particularly for uremic toxins of middle and large molecular weight. High-flux dialysers have been evaluated in clinical and epidemiological studies for their effect on mortality, morbidity, dialysis-related amyloidosis, nutritional status, response to erythropoietin treatment, dialysis tolerance and the preservation of residual renal function. Many of these studies, however, lack a prospective design and randomised treatment allocation, or have too few patients and too short a follow-up. Therefore, this clinical trial was designed to prospectively investigate the long-term effect of membrane permeability on clinical outcome in a larger number of patients. The primary objective is to compare the effect of membrane permeability on mortality of patients on bicarbonate hemodialysis and treated with a minimum dialysis dose. Patients included in the study should have been on hemodialysis for no longer than one month and have serum albumin 4 g/dl or lower. Patients will be randomised to either the experimental or the control group. During the four-week run-in period the treatment parameters will be established in order to achieve the required dialysis dose. During the maintenance period of three to five years regular visits are scheduled to record clinical and laboratory parameters, to measure Kt/V and to adapt the treatment parameters. Altogether a minimum of 660 patients should be enrolled within a two-year recruitment period.

Chemokines in chronic progressive neurological diseases: HTLV-1 associated myelopathy and multiple sclerosis

It is hypothesized that in MS and HTLV-1, chemokine and chemokine receptor expression are important mechanisms by which T cells migrate to sites of inflammation. Preliminary evidence supports the roles of several chemokines, including MIP 1beta, in mediating the enhanced migration capacity of MS derived PBLs. In addition, the ligand CCR-5 seems to be up regulated on PBLs from some MS patients. Analysis of T cell clones does not reveal a definite correlation between cytokine phenotype and chemokine receptor profile. The chemokines and chemokine receptor family are likely to be important molecules in chronic progressive neurological diseases, in which immune cells invade the central nervous system.

Direct analysis of viral-specific CD8+ T cells with soluble HLA-A2/Tax11-19 tetramer complexes in patients with human T cell lymphotropic virus-associated myelopathy

Human T cell lymphotropic virus-I (HTLV-I)-associated myelopathy is a slowly progressive neurologic disease characterized by inflammatory infiltrates in the central nervous system accompanied by clonal expansion of HTLV-I-reactive CD8+ T-cells. In patients carrying the HLA-A2 allele, the immune response is primarily directed to the Tax11-19 peptide. The frequency, activation state, and TCR usage of HLA-A2/Tax11-19 binding T cells in patients with HTLV-I-associated myelopathy was determined using MHC class I tetramers loaded with the Tax11-19 peptide. Circulating Tax11-19-reactive T cells were found at very high frequencies, approaching 1:10 circulating CD8+ T cells. T cells binding HLA-A2/Tax11-19 consisted of heterogeneous populations expressing different chemokine receptors and the IL-2R beta-chain but not the IL-2R alpha-chain. Additionally, Tax11-19-reactive CD8+ T cells used one predominant TCR Vbeta-chain for the recognition of the HLA-A2/Tax11-19 complex. These data provide direct evidence for high frequencies of circulating Tax11-19-reactive CD8+ T cells in patients with HTLV-I-associated myelopathy.

Reduction in HTLV-I proviral load and spontaneous lymphoproliferation in HTLV-I-associated myelopathy/tropical spastic paraparesis patients treated with humanized anti-Tac

Human T-lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a neurological disease that results from an interaction of retroviral infection and immune activation. In this study, five doses (1 mg/kg) of humanized anti-Tac antibody were administered to 9 HAM/TSP patients at weeks 0, 2, 6, 10, and 14. Preliminary immunological studies on HAM/TSP patients treated with humanized anti-Tac indicate that there is a selective down-regulation of activated T cells and a decrease in the HTLV-I viral load in peripheral blood lymphocytes, most likely through the selective removal of HTLV-I-infected, activated CD4+ lymphocytes.

The effect of human beta2-microglobulin on major histocompatibility complex I peptide loading and the engineering of a high affinity variant. Implications for peptide-based vaccines

The ability to directly load cell surface major histocompatibility complex (MHC) class I molecules with peptides provides a potentially powerful approach toward the development of vaccines to generate cell-mediated immunity. We demonstrate that exogenous beta2-microglobulin (beta2m) stabilizes human cell surface MHC I molecules and facilitates their loading with exogenous peptides. Additionally, using three-dimensional crystal structures and known interaction sites between MHC I heavy chains and beta2m, we engineered variants of human beta2m (hbeta2m) with a single serine substitution at residue 55. This alteration was predicted to promote hydrophobic interactions at the MHC I heavy chain/beta2m interface and displace an ordered water molecule. Compared with hbeta2m, the serine to valine substitution at residue 55 had improved ability to bind to cell surface HLA-A1, HLA-A2, and HLA-A3 molecules, facilitate exogenous peptide loading, and promote recognition by peptide-specific T cells. The inclusion of hbeta2m or higher affinity variants when pulsing cells with MHC-restricted peptides increases the efficiency of peptide loading 50-80-fold. Therefore, the inclusion of hbeta2m in peptide-based vaccines may increase cell surface antigen densities above thresholds that allow recognition of peptide antigens by the immune system, particularly for cryptic, subdominant, or marginally antigenic peptides.

The effects of anesthesia and gender on intraocular pressure in lions (Panthera leo)

Intraocular pressure (IOP) was measured in a pride of 22 (11 males, 11 females) lions (Panthera leo) using a Schiotz tonometer. Two anesthetic protocols were used in the study. Lions in group I (n = 14) were anesthetized using xylazine, atropine sulfate, and ketamine. Lions in group II (n = 8) were anesthetized using ketamine and diazepam. Five sequential readings were taken from each eye of every lion. There were no significant differences in IOP between the two anesthetic groups, between left and right eyes, or over the five readings. The IOP was significantly higher in males than in females, controlling for age and weight. The mean (+/-SD) tonometer reading in 22 eyes of 11 male lions was 2.9 (+/-0.5) mm; with a 95% confidence interval (CI) of 1.6-4.5 mm. The mean tonometer reading in 22 eyes of 11 female lions was 4.0 (+/-0.7) mm, with a 95% CI of 1.8-6.3 mm. Using the 1955 Friedenwald human calibration table, the estimated mean IOP in 22 eyes of 11 male lions was 24.9 (+/-2.0) mm Hg, with a 95% CI of 20.4-29.4 mm Hg. The estimated mean IOP in 22 eyes of 11 female lions was 20.9 (+/-2.4) mm Hg, with a 95% CI of 15.6-26.3 mm Hg.

A comparison of nebulized budesonide, intramuscular dexamethasone, and placebo for moderately severe croup

BACKGROUND

In children with croup, treatment with nebulized budesonide decreases symptoms, but it is uncertain how budesonide compares with dexamethasone, the conventional therapy for croup, and whether either reduces the rate of hospitalization.

METHODS

We performed a double-blind, randomized trial involving 144 children with moderately severe croup. The children were treated with racepinephrine and a single dose of 4 mg of nebulized budesonide (48 children), 0.6 mg of intramuscular dexamethasone per kilogram of body weight (47 children), or placebo (49 children). The children were assessed before treatment and then hourly for five hours after treatment. Physicians who were unaware of the treatment assignments determined the children's need for further treatment and hospitalization.

RESULTS

The characteristics of the groups were similar at base line, including the types of viruses identified, the types of croup, and the clinical severity of the illness. The overall rates of hospitalization were 71 percent in the placebo group (35 of 49 children), 38 percent in the budesonide group (18 of 48 children), and 23 percent in the dexamethasone group (11 of 47 children) (unadjusted P=0.001 for the comparison of budesonide with placebo, P<0.001 for the comparison of dexamethasone with placebo, and P=0.18 for the comparison of budesonide with dexamethasone). Children treated with budesonide or dexamethasone had a greater improvement in croup scores than those given placebo (P=0.03 and P<0.001, respectively), and those treated with dexamethasone had a greater improvement than those treated with budesonide (P=0.003).

CONCLUSIONS

In children with moderately severe croup, treatment with intramuscular dexamethasone or nebulized budesonide resulted in more rapid clinical improvement than did the administration of placebo, with dexamethasone offering the greatest improvement. Treatment with either glucocorticoid resulted in fewer hospitalizations.

Demonstration of human T lymphotropic virus type I (HTLV-I) tax-specific CD8+ lymphocytes directly in peripheral blood of HTLV-I-associated myelopathy/tropical spastic paraparesis patients by intracellular cytokine detection

Human T lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is an inflammatory neurologic disease caused by HTLV-I infection and has been associated with elevated levels of several proinflammatory cytokines in both serum and cerebrospinal fluid. It is unknown what kind of cells secrete these cytokines and if HTLV-I Ags are associated with this phenomenon. Here, we investigated the expression of cytokines in PBL from eight HAM/TSP patients, nine HTLV-I-infected asymptomatic carriers, and seven healthy controls by flow cytometry combined with intracellular cytokine staining. PBL were cultured with brefeldin A without mitogen and IL-2 for 14 h. Under these conditions, CD8+ cells produced proinflammatory cytokines including IFN-gamma, TNF-alpha, and IL-2, which were significantly elevated in HAM/TSP patients. The proportion of CD8+ cells producing IFN-gamma in HAM/TSP patients, asymptomatic carriers, and healthy controls were, on average, 4.9, 0.4, and 0.3%, respectively. IFN-gamma production by these CD8+ cells was suppressed by anti-HLA-class I Ab. Purified CD8+ cells from an HLA-A2 HAM/TSP patient produced IFN-gamma by cocultivation with autologous CD4 cells, the main reservoir of HTLV-I in vivo, or allogenic HLA-A2+ B cells pulsed with a known immunodominant HTLV-I tax peptide. These data suggest that high levels of circulating HTLV-I-specific CD8+ T lymphocytes have the potential to produce proinflammatory cytokines and may promote inflammatory responses to HTLV-I in HAM/TSP patients.

Neuronal molecular mimicry in immune-mediated neurologic disease

Molecular mimicry is implicated in the pathogenesis of autoimmune diseases such as diabetes mellitus, rheumatoid arthritis, and multiple sclerosis (MS). Cellular and antibody-mediated immune responses to shared viral-host antigens have been associated with the development of disease in these patients. Patients infected with human T-lymphotropic virus type I (HTLV-I) develop HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP), an immune-mediated disorder of the central nervous system (CNS) that resembles some forms of MS. Damage to neuronal processes in the CNS of HAM/TSP patients is associated with an activated cellular and antibody-mediated immune response. In this study, IgG isolated from HAM/TSP patients was immunoreactive with uninfected neurons and this reactivity was HTLV-I specific. HAM/TSP IgG stained uninfected neurons in human CNS and cell lines but not nonneuronal cells. Neuronal western blots showed IgG reactivity with a single 33-kd band in all HAM/TSP patients tested. By contrast, no neuron-specific IgG reactivity could be demonstrated from HTLV-I seronegative controls and, more important, from HTLV-I seropositive, neurologically asymptomatic individuals. Both immunocytochemical staining and western blot reactivity were abolished by preincubating HAM/TSP IgG with HTLV-I protein lysate but not by control proteins. Staining of CNS tissue by a monoclonal antibody to HTLV-I tax (an immunodominant HTLV-I antigen) mimicked HAM/TSP IgG immunoreactivity. There was no staining by control antibodies. Absorption of HAM/TSP IgG with recombinant HTLV-I tax protein or preincubation of CNS tissue with the monoclonal antibody to HTLV-I tax abrogated the immunocytochemical and western blot reactivity of HAM/TSP IgG. Furthermore, in situ human IgG localized to neurons in HAM/TSP brain but not in normal brain. These data indicate that HAM/TSP patients develop an antibody response that targets uninfected neurons, yet reactivity is blocked by HTLV-I, suggesting viral-specific autoimmune reactivity to the CNS, the damaged target organ in HAM/TSP.

Direct visualization of antigen-specific T cells: HTLV-1 Tax11-19- specific CD8(+) T cells are activated in peripheral blood and accumulate in cerebrospinal fluid from HAM/TSP patients

Human T lymphotropic virus type 1 (HTLV-1) -associated myelopathy/tropic spastic paraparesis is a demyelinating inflammatory neurologic disease associated with HTLV-1 infection. HTLV-1 Tax11-19-specific cytotoxic T cells have been isolated from HLA-A2-positive patients. We have used a peptide-loaded soluble HLA-A2-Ig complex to directly visualize HTLV-1 Tax11-19-specific T cells from peripheral blood and cerebrospinal fluid without in vitro stimulation. Five of six HTLV-1-associated myelopathy/tropic spastic paraparesis patients carried a significant number (up to 13.87%) of CD8(+) lymphocytes specific for the HTLV-1 Tax11-19 peptide in their peripheral blood, which were not found in healthy controls. Simultaneous comparison of peripheral blood and cerebrospinal fluid from one patient revealed 2.5-fold more Tax11-19-specific T cells in the cerebrospinal fluid (23.7% vs. 9.4% in peripheral blood lymphocyte). Tax11-19-specific T cells were seen consistently over a 9-yr time course in one patient as far as 19 yrs after the onset of clinical symptoms. Further analysis of HTLV-1 Tax11-19-specific CD8(+) T lymphocytes in HAM/TSP patients showed different expression patterns of activation markers, intracellular TNF-alpha and gamma-interferon depending on the severity of the disease. Thus, visualization of antigen-specific T cells demonstrates that HTLV-1 Tax11-19-specific CD8(+) T cells are activated, persist during the chronic phase of the disease, and accumulate in cerebrospinal fluid, showing their pivotal role in the pathogenesis of this neurologic disease.

ELI-spot of Th-1 cytokine secreting PBMC's in multiple sclerosis: correlation with MRI lesions

The Th1-like cytokines, interleukin 2 (IL-2), interferon gamma (IFN-gamma), and lymphotoxin alpha (LT-alpha) have been implicated in the immunopathogenesis of multiple sclerosis (MS) and experimental allergic encephalomyelitis (EAE), an animal model of immune mediated demyelination. These cytokines have been associated with opening of the blood brain barrier (BBB) in EAE and in vitro, but not in MS. We used an enzyme-linked immunospot (ELI-spot) assay to measure relative numbers of cytokine-secreting peripheral blood mononuclear cells (PBMC) from eight MS patients who were followed with serial monthly contrast-enhanced head magnetic resonance imagings (MRI) and phlebotomy. We found a significant positive correlation between changes in IL-2 secreting cells and MRI lesions over a 6-month time period. There was a weaker association between contrast-enhancing MRI lesions and IFN-gamma or LT-alpha secreting cells. These data are the first to show a significant positive correlation between any cytokine and serial gadolinium (Gd-) MRI disease activity in MS patients. The association between IFN-gamma and LT-alpha secretion and MRI lesions is less clear.

Review of a home-based palliative care program for children with malignant and non-malignant diseases

This retrospective chart review presents the patient characteristics and utilization of the home-based palliative care program at The Hospital for Sick Children in Toronto. A total of 126 children dying from a broad spectrum of diseases was admitted during the period 1986-1994, referred from neurosurgery, genetic/metabolic, neurology, neonatology, nephrology, cardiology, general pediatrics, general surgery, and pulmonology. At the time of review, 15 patients remained alive and 18 had been discharged from the program. Mean age at the time of referral was 4.8 +/- 0.51 years and mean age at death was 5.3 +/- 0.55 years. The mean number of days in hospital was 26.5 +/- 14.6 while days spent at home averaged 98.4 +/- 15.2; thus 80% of the children's remaining time was spent at home. The average number of parent-team contacts was 3.5 +/- 0.9 by pager and 24.0 +/- 2.9 by telephone. Of the 93 patients who died in the program, 53% died at home, 18% died in community hospitals, and 29% died in a tertiary care facility. Analgesic medications were administered to 54% of the patients; 56% of these then required opioid analgesia for pain and symptom management. Home-based palliative care appeared to be an effective program for many children with a variety of terminal illnesses after adequate supports for the child and family had been established.

Effects of Dispersant Treatment on the Acute Aquatic Toxicity of Petroleum Hydrocarbons

The acute effects of both untreated and dispersant-treated Prudhoe Bay crude oil on the early life-stages of three marine species were investigated. Identification of which water-accommodated fraction (undispersed or chemically dispersed) was considered "more toxic" was dependent on species, time, and endpoint (and by inference, test protocol). Generally, the data showed that at roughly equivalent hydrocarbon concentrations untreated oil solutions resulted in higher initial effects (< 1 h) in mysid and topsmelt tests, whereas dispersed oil solutions elicited higher levels of larval abnormality in abalone tests and higher levels of mortality in mysid tests. While differences in test protocols existed among the species tested, topsmelt were the most sensitive species to untreated oil solutions, with mysids being most sensitive to dispersed oil solutions.

Astrocyte-specific expression of human T-cell lymphotropic virus type 1 (HTLV-1) Tax: induction of tumor necrosis factor alpha and susceptibility to lysis by CD8+ HTLV-1-specific cytotoxic T cells

Human T-cell lymphotropic virus type 1 (HTLV-1) is associated with a chronic neurological disease termed HTLV-1-associated myelopathy/tropical spastic paraperesis (HAM/TSP). Although the pathogenesis of this disease remains to be elucidated, the evidence suggests that immunopathological mechanisms are involved. Since HTLV-1 tax mRNA was colocalized with glial acidic fibrillary protein, a marker for astrocytes, we developed an in vitro model to assess whether HTLV-1 infection activates astrocytes to secrete cytokines or present viral immunodominant epitopes to virus-specific T cells. Two human astrocytic glioma cell lines, U251 and U373, were transfected with the 3' portion of the HTLV-1 genome and with the HTLV-1 tax gene under astrocyte-specific promoter control. In this study, we report that Tax-expressing astrocytic glioma transfectants activate the expression of tumor necrosis factor alpha mRNA in vitro. Furthermore, these Tax-expressing glioma transfectants can serve as immunological targets for HTLV-1-specific cytotoxic T lymphocytes (CTL). We propose that these events could contribute to the neuropathology of HAM/TSP, since infected astrocytes can become a source for inflammatory cytokines upon HTLV-1 infection and serve as targets for HTLV-1-specific CTL, resulting in parenchymal damage by direct lysis and/or cytokine release.

C2H2-546: a zinc finger protein differentially expressed in HTLV-1 infected T cells

We report the cloning and characterization of a novel cDNA termed C2H2-546 which encodes a C2H2-type zinc finger protein. C2H2-546 RNA is expressed in the HTLV-1 infected T cells examined which were derived from HAM-TSP patients, but not in T cells derived from ATL patients. The C2H2-546 gene is conserved in humans and primates and maps to chromosome 10q11.2, a site associated with a variety of cancers. Thus, C2H2-546 is a candidate regulatory molecule important in the formation of these tumors, and may serve as an important marker to distinguish HTLV-1 infected ATL versus HAM-TSP T cell lineages.

Association of human herpes virus 6 (HHV-6) with multiple sclerosis: increased IgM response to HHV-6 early antigen and detection of serum HHV-6 DNA

Viruses have long been suggested to be involved in the etiology of multiple sclerosis (MS). This suggestion is based on (1) epidemiological evidence of childhood exposure to infectious agents and increase in disease exacerbations with viral infection; (2) geographic association of disease susceptibility with evidence of MS clustering; (3) evidence that migration to and from high-risk areas influences the likelihood of developing MS; (4) abnormal immune responses to a variety of viruses; and (5) analogy with animal models and other human diseases in which viruses can cause diseases with long incubation periods, a relapsing-remitting course, and demyelination. Many of these studies involve the demonstration of increased antibody titers to a particular virus, whereas some describe isolation of virus from MS material. However, no virus to date has been definitively associated with this disease. Recently, human herpesvirus 6 (HHV-6), a newly described beta-herpes virus that shares homology with cytomegalovirus (CMV), has been reported to be present in active MS plaques. In order to extend these observations, we have demonstrated increased IgM serum antibody responses to HHV-6 early antigen (p41/38) in patients with relapsing-remitting MS (RRMS), compared with patients with chronic progressive MS (CPMS), patients with other neurologic disease (OND), patients with other autoimmune disease (OID), and normal controls. Given the ubiquitous nature of this virus and the challenging precedent of correlating antiviral antibodies with disease association, these antibody studies have been supported by the detection of HHV-6 DNA from samples of MS serum as a marker of active viral infection.

Behavioral and pharmacologic treatment of delirium

Delirium is an acute confusional state with a fluctuating course. Since the syndrome of delirium is associated with derangements of cognition, attention and level of consciousness, it can cause behaviors that are difficult to manage. Hallucinations, agitation, insomnia and anxiety are common in the delirious patient. Behavioral and pharmacologic interventions can be used while the underlying etiology of delirium is sought. Nonpharmacologic measures include frequent reassurance, environmental cues to reorient the patient and the judicious use of physical restraints. Haloperidol, which has negligible anticholinergic effects, is the drug most often used to treat the symptoms of delirium. Short-acting benzodiazepines may be useful in patients with delirium caused by alcohol withdrawal, but these agents may cause increased agitation in elderly patients and patients with hepatic dysfunction.

Correlation of morphine sulfate in blood plasma and saliva in pediatric patients

This study sought to determine whether saliva concentrations of morphine correlate with plasma levels of morphine in pediatric patients receiving morphine analgesia for severe pain, and to evaluate whether the measurement of saliva morphine concentrations would be a useful, noninvasive, clinical tool to diagnose systemic exposure to morphine. Fifteen pediatric patients were enrolled; for the control group, 18 adult volunteers were recruited. Patients received continuous morphine drips to ameliorate pain caused by a sickle cell vasoocclusive crisis (range, 10-40 micrograms/kg.h). Control subjects were randomized into those receiving acetaminophen with either 8 mg (n = 13) or 30 mg (n = 5) of codeine. All participants fasted at least 2 hours before sample collection. Blood and saliva samples were collected simultaneously. All samples were analyzed by radioimmunoassay for morphine. There was no correlation between saliva and plasma morphine concentrations in either the patients receiving intravenous morphine (r = 0.04, P = 0.89) or in the controls receiving codeine (r = 0.43, P = 0.08). There was no observed difference in the mean counts per minute (CPM) for saliva samples in the pH range 3.96 to 8.06. Saliva concentrations of morphine cannot be used to predict the plasma concentration of morphine in children or adults. However, the concentration of morphine in saliva may be used as a qualitative indicator of systemic exposure to morphine in a subject.

Accumulation of human T lymphotropic virus (HTLV)-I-specific T cell clones in HTLV-I-associated myelopathy/tropical spastic paraparesis patients

Human T lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraperesis (HAM/TSP) is a slowly progressive neurologic disorder following infection with HTLV-I. It is characterized by spasticity and hyper-reflexia of the lower extremities, urinary bladder disturbance, lower extremity muscle weakness, and sensory disturbances. HTLV-I, as an inducer of a strong humoral and cytotoxic response, is a well-known pathogenic factor for the progression of HAM/TSP. Peptides derived from proviral tax and env genes provide epitopes recognized by T cells. We herein report an accumulation of distinct clonotypes of alpha/beta TCR+ peripheral blood T lymphocytes from HAM/TSP patients in comparison with that observed in both asymptomatic carriers and healthy controls, using the reverse-transcriptase PCR/single-strand conformation polymorphism method. We also found that some of the accumulated T cell clones in the peripheral blood and cerebrospinal fluid are HTLV-I Tax(11-19) peptide specific. Such clones were found to expand strongly after being cultured with an HTLV-I Tax(11-19) peptide. Moreover, the cultured samples exhibited a strong MHC class I-restricted cytotoxic activity against HTLV-I Tax(11-19) peptide-expressing targets, and therefore most likely also include the disease-associated T cell clones observed in the patients. This is the first report of a direct assessment of Ag-specific T cell responses in fresh PBL and cerebrospinal fluid.