CNS myelin induces regulatory functions of DC-SIGN-expressing, antigen-presenting cells via cognate interaction with MOG

Human myelin oligodendrocyte glycoprotein is decorated with fucosylated N-glycans that are recognized by DC-SIGN⁺ DCs and microglia that control immune homeostasis.

Myelin oligodendrocyte glycoprotein (MOG), a constituent of central nervous system myelin, is an important autoantigen in the neuroinflammatory disease multiple sclerosis (MS). However, its function remains unknown. Here, we show that, in healthy human myelin, MOG is decorated with fucosylated N-glycans that support recognition by the C-type lectin receptor (CLR) DC-specific intercellular adhesion molecule-3–grabbing nonintegrin (DC-SIGN) on microglia and DCs. The interaction of MOG with DC-SIGN in the context of simultaneous TLR4 activation resulted in enhanced IL-10 secretion and decreased T cell proliferation in a DC-SIGN-, glycosylation-, and Raf1-dependent manner. Exposure of oligodendrocytes to proinflammatory factors resulted in the down-regulation of fucosyltransferase expression, reflected by altered glycosylation at the MS lesion site. Indeed, removal of fucose on myelin reduced DC-SIGN–dependent homeostatic control, and resulted in inflammasome activation, increased T cell proliferation, and differentiation toward a Th₁₇-prone phenotype. These data demonstrate a new role for myelin glycosylation in the control of immune homeostasis in the healthy human brain through the MOG–DC-SIGN homeostatic regulatory axis, which is comprised by inflammatory insults that affect glycosylation. This phenomenon should be considered as a basis to restore immune tolerance in MS.

Large-scale quarantine following biological terrorism in the United States: scientific examination, logistic and legal limits, and possible consequences

Concern for potential bioterrorist attacks causing mass casualties has increased recently. Particular attention has been paid to scenarios in which a biological agent capable of person-to-person transmission, such as smallpox, is intentionally released among civilians. Multiple public health interventions are possible to effect disease containment in this context. One disease control measure that has been regularly proposed in various settings is the imposition of large-scale or geographic quarantine on the potentially exposed population. Although large-scale quarantine has not been implemented in recent US history, it has been used on a small scale in biological hoaxes, and it has been invoked in federally sponsored bioterrorism exercises. This article reviews the scientific principles that are relevant to the likely effectiveness of quarantine, the logistic barriers to its implementation, legal issues that a large-scale quarantine raises, and possible adverse consequences that might result from quarantine action. Imposition of large-scale quarantine-compulsory sequestration of groups of possibly exposed persons or human confinement within certain geographic areas to prevent spread of contagious disease-should not be considered a primary public health strategy in most imaginable circumstances. In the majority of contexts, other less extreme public health actions are likely to be more effective and create fewer unintended adverse consequences than quarantine. Actions and areas for future research, policy development, and response planning efforts are provided.

Death due to bioterrorism-related inhalational anthrax: report of 2 patients

On October 9, 2001, a letter containing anthrax spores was mailed from New Jersey to Washington, DC. The letter was processed at a major postal facility in Washington, DC, and opened in the Senate's Hart Office Building on October 15. Between October 19 and October 26, there were 5 cases of inhalational anthrax among postal workers who were employed at that major facility or who handled bulk mail originating from that facility. The cases of 2 postal workers who died of inhalational anthrax are reported here. Both patients had nonspecific prodromal illnesses. One patient developed predominantly gastrointestinal symptoms, including nausea, vomiting, and abdominal pain. The other patient had a "flulike" illness associated with myalgias and malaise. Both patients ultimately developed dyspnea, retrosternal chest pressure, and respiratory failure requiring mechanical ventilation. Leukocytosis and hemoconcentration were noted in both cases prior to death. Both patients had evidence of mediastinitis and extensive pulmonary infiltrates late in their course of illness. The durations of illness were 7 days and 5 days from onset of symptoms to death; both patients died within 24 hours of hospitalization. Without a clinician's high index of suspicion, the diagnosis of inhalational anthrax is difficult during nonspecific prodromal illness. Clinicians have an urgent need for prompt communication of vital epidemiologic information that could focus their diagnostic evaluation. Rapid diagnostic assays to distinguish more common infectious processes from agents of bioterrorism also could improve management strategies.

Phase I trial of lobradimil (RMP-7) and carboplatin in children with brain tumors

PURPOSE

To determine the maximum tolerated dose (MTD), the incidence and severity of toxicities, and the pharmacokinetics of lobradimil administered intravenously over 10 min in combination with carboplatin in children with refractory brain tumors.

METHODS

A group of 25 children with primary brain tumors received carboplatin and lobradimil on two consecutive days every 28 days. The 10-min lobradimil infusion began 5 min before the end of the carboplatin infusion. Four lobradimil dose levels (100, 300, 450 and 600 ng/kg ideal body weight, IBW) were studied in cohorts of 4 to 13 patients. Carboplatin was adaptively dosed based on the glomerular filtration rate to achieve a target plasma area under the concentration-time curve (AUC) of 7.0 mg min/ml per course (5.0 mg min/ml for patients who had previously received craniospinal radiation or myeloablative chemotherapy).

RESULTS

Lobradimil toxicity was immediate, tolerable and rapidly reversible. The most frequent toxicities were hypotension, flushing, headache and gastrointestinal complaints. One patient on the 600 ng/kg dose level had a seizure during the lobradimil infusion. The incidence and severity of lobradimil toxicities were not dose-related and the lobradimil dose was not escalated beyond the 600 ng/kg IBW dose level. Two patients had partial responses and ten patients had stable disease. Myelosuppression (thrombocytopenia more prominent than neutropenia) was the primary toxicity attributed to carboplatin. Lobradimil pharmacokinetics were characterized by rapid clearance from the plasma compartment and substantial interpatient variability.

CONCLUSIONS

The combination of carboplatin and lobradimil is safe and tolerable. An MTD for lobradimil was not defined because toxicity was not dose-related. The recommended pediatric phase II dose of lobradimil is 600 ng/kg IBW.

Tularemia as a biological weapon: medical and public health management

OBJECTIVE

The Working Group on Civilian Biodefense has developed consensus-based recommendations for measures to be taken by medical and public health professionals if tularemia is used as a biological weapon against a civilian population.

PARTICIPANTS

The working group included 25 representatives from academic medical centers, civilian and military governmental agencies, and other public health and emergency management institutions and agencies.

EVIDENCE

MEDLINE databases were searched from January 1966 to October 2000, using the Medical Subject Headings Francisella tularensis, Pasteurella tularensis, biological weapon, biological terrorism, bioterrorism, biological warfare, and biowarfare. Review of these references led to identification of relevant materials published prior to 1966. In addition, participants identified other references and sources.

CONSENSUS PROCESS

Three formal drafts of the statement that synthesized information obtained in the formal evidence-gathering process were reviewed by members of the working group. Consensus was achieved on the final draft.

CONCLUSIONS

A weapon using airborne tularemia would likely result 3 to 5 days later in an outbreak of acute, undifferentiated febrile illness with incipient pneumonia, pleuritis, and hilar lymphadenopathy. Specific epidemiological, clinical, and microbiological findings should lead to early suspicion of intentional tularemia in an alert health system; laboratory confirmation of agent could be delayed. Without treatment, the clinical course could progress to respiratory failure, shock, and death. Prompt treatment with streptomycin, gentamicin, doxycycline, or ciprofloxacin is recommended. Prophylactic use of doxycycline or ciprofloxacin may be useful in the early postexposure period.

Emerging illness and bioterrorism: implications for public health

Biological weapons have the potential to inflict deliberate, potentially devastating epidemics of infectious disease on populations. The science and technology exist to create deliberate outbreaks of human disease, as well as disease among plants and animals, crops, and livestock. A new awareness among policymakers of the link between public health and national security requires the attention of public health professionals. The issues posed by biological weapons are likely to challenge the political assumptions of many progressive public health professionals and will demand new coalitions. The prospect of bioterrorism may offer new opportunities for improving the public health infrastructure and its capabilities.

Botulinum toxin as a biological weapon: medical and public health management

OBJECTIVE

The Working Group on Civilian Biodefense has developed consensus-based recommendations for measures to be taken by medical and public health professionals if botulinum toxin is used as a biological weapon against a civilian population.

PARTICIPANTS

The working group included 23 representatives from academic, government, and private institutions with expertise in public health, emergency management, and clinical medicine.

EVIDENCE

The primary authors (S.S.A. and R.S.) searched OLDMEDLINE and MEDLINE (1960-March 1999) and their professional collections for literature concerning use of botulinum toxin as a bioweapon. The literature was reviewed, and opinions were sought from the working group and other experts on diagnosis and management of botulism. Additional MEDLINE searches were conducted through April 2000 during the review and revisions of the consensus statement.

CONSENSUS PROCESS

The first draft of the working group's consensus statement was a synthesis of information obtained in the formal evidence-gathering process. The working group convened to review the first draft in May 1999. Working group members reviewed subsequent drafts and suggested additional revisions. The final statement incorporates all relevant evidence obtained in the literature search in conjunction with final consensus recommendations supported by all working group members.

CONCLUSIONS

An aerosolized or foodborne botulinum toxin weapon would cause acute symmetric, descending flaccid paralysis with prominent bulbar palsies such as diplopia, dysarthria, dysphonia, and dysphagia that would typically present 12 to 72 hours after exposure. Effective response to a deliberate release of botulinum toxin will depend on timely clinical diagnosis, case reporting, and epidemiological investigation. Persons potentially exposed to botulinum toxin should be closely observed, and those with signs of botulism require prompt treatment with antitoxin and supportive care that may include assisted ventilation for weeks or months. Treatment with antitoxin should not be delayed for microbiological testing.

A plague on your city: observations from TOPOFF

The United States Congress directed the Department of Justice to conduct an exercise engaging key personnel in the management of mock chemical, biological, or cyberterrorist attacks. The resulting exercise was called "TOPOFF," named for its engagement of top officials of the United States government. This article offers a number of medical and public health observations and lessons discovered during the bioterrorism component of the exercise. The TOPOFF exercise illuminated problematic issues of leadership and decision-making; the difficulties of prioritization and distribution of scarce resources; the crisis that contagious epidemics would cause in health care facilities; and the critical need to formulate sound principles of disease containment. These lessons should provoke consideration of future directions for bioterrorism planning and preparedness at all levels of government and among the many communities and practitioners with responsibilities for national security and public health.

Leptin signaling in human peripheral blood mononuclear cells, activation of p38 and p42/44 mitogen-activated protein (MAP) kinase and p70 S6 kinase

The adipocyte-derived hormone leptin plays an important role as a relayer of nutritional status to several organ systems. Evidence is accumulating that leptin plays an important role in the adequate functioning and maintenance of the immune system. Here we show that leptin induces sustained phosphorylation of p38 MAP kinase in human peripheral blood mononuclear cells (PBMCs). We show furthermore that leptin induces two routes to phosphorylation of the 40S ribosomal protein S6, one is activation of the p90 ribosomal S6 kinase (RSK) via the MEK/p42/p44 MAP kinase pathway, the other is via activation of p70 S6 kinase. Thus, these results give new insight in the mechanism that underlies the immunomodulatory effects of leptin.

Preventing the use of biological weapons: improving response should prevention fail

This article presents an overview of the nature and scope of the challenges posed by biological weapons, and offers ways by which the infectious diseases professional community might address the challenges of biological weapons and bioterrorism.

Plague as a biological weapon: medical and public health management. Working Group on Civilian Biodefense

OBJECTIVE

The Working Group on Civilian Biodefense has developed consensus-based recommendations for measures to be taken by medical and public health professionals following the use of plague as a biological weapon against a civilian population.

PARTICIPANTS

The working group included 25 representatives from major academic medical centers and research, government, military, public health, and emergency management institutions and agencies.

EVIDENCE

MEDLINE databases were searched from January 1966 to June 1998 for the Medical Subject Headings plague, Yersinia pestis, biological weapon, biological terrorism, biological warfare, and biowarfare. Review of the bibliographies of the references identified by this search led to subsequent identification of relevant references published prior to 1966. In addition, participants identified other unpublished references and sources. Additional MEDLINE searches were conducted through January 2000.

CONSENSUS PROCESS

The first draft of the consensus statement was a synthesis of information obtained in the formal evidence-gathering process. The working group was convened to review drafts of the document in October 1998 and May 1999. The final statement incorporates all relevant evidence obtained by the literature search in conjunction with final consensus recommendations supported by all working group members.

CONCLUSIONS

An aerosolized plague weapon could cause fever, cough, chest pain, and hemoptysis with signs consistent with severe pneumonia 1 to 6 days after exposure. Rapid evolution of disease would occur in the 2 to 4 days after symptom onset and would lead to septic shock with high mortality without early treatment. Early treatment and prophylaxis with streptomycin or gentamicin or the tetracycline or fluoroquinolone classes of antimicrobials would be advised.

Smallpox as a biological weapon: medical and public health management. Working Group on Civilian Biodefense

OBJECTIVE

To develop consensus-based recommendations for measures to be taken by medical and public health professionals following the use of smallpox as a biological weapon against a civilian population.

PARTICIPANTS

The working group included 21 representatives from staff of major medical centers and research, government, military, public health, and emergency management institutions and agencies. Evidence The first author (D.A.H.) conducted a literature search in conjunction with the preparation of another publication on smallpox as well as this article. The literature identified was reviewed and opinions were sought from experts in the diagnosis and management of smallpox, including members of the working group.

CONSENSUS PROCESS

The first draft of the consensus statement was a synthesis of information obtained in the evidence-gathering process. Members of the working group provided formal written comments that were incorporated into the second draft of the statement. The working group reviewed the second draft on October 30, 1998. No significant disagreements existed and comments were incorporated into a third draft. The fourth and final statement incorporates all relevant evidence obtained by the literature search in conjunction with final consensus recommendations supported by all working group members.

CONCLUSIONS

Specific recommendations are made regarding smallpox vaccination, therapy, postexposure isolation and infection control, hospital epidemiology and infection control, home care, decontamination of the environment, and additional research needs. In the event of an actual release of smallpox and subsequent epidemic, early detection, isolation of infected individuals, surveillance of contacts, and a focused selective vaccination program will be the essential items of an effective control program.

Anthrax as a biological weapon: medical and public health management. Working Group on Civilian Biodefense

OBJECTIVE

To develop consensus-based recommendations for measures to be taken by medical and public health professionals following the use of anthrax as a biological weapon against a civilian population.

PARTICIPANTS

The working group included 21 representatives from staff of major academic medical centers and research, government, military, public health, and emergency management institutions and agencies.

EVIDENCE

MEDLINE databases were searched from January 1966 to April 1998, using the Medical Subject Headings anthrax, Bacillus anthracis, biological weapon, biological terrorism, biological warfare, and biowarfare. Review of references identified by this search led to identification of relevant references published prior to 1966. In addition, participants identified other unpublished references and sources.

CONSENSUS PROCESS

The first draft of the consensus statement was a synthesis of information obtained in the formal evidence-gathering process. Members of the working group provided formal written comments which were incorporated into the second draft of the statement. The working group reviewed the second draft on June 12, 1998. No significant disagreements existed and comments were incorporated into a third draft. The fourth and final statement incorporates all relevant evidence obtained by the literature search in conjunction with final consensus recommendations supported by all working group members.

CONCLUSIONS

Specific consensus recommendations are made regarding the diagnosis of anthrax, indications for vaccination, therapy for those exposed, postexposure prophylaxis, decontamination of the environment, and additional research needs.

Debilitating reaction following the initial dose of tramadol

OBJECTIVE

To describe a debilitating reaction following a single oral dose of tramadol.

CASE SUMMARY

A 32-year-old white man with no prior medical problems, allergies, or previous medication reactions experienced ataxia, dilation of the pupils, numbness in his arms and legs, tremulousness, and dysphoria lasting approximately 4 hours following an initial tramadol dose (100 mg). The patient recovered with no sequelae.

DISCUSSION

Central nervous system (CNS) stimulation during therapy with tramadol was reported in 7% of patients in clinical trials. These reactions are usually mild and transient. This report describes a debilitating CNS-mediated reaction to an initial dose of tramadol in an otherwise healthy adult. The patient was phenotyped for CYP2D6 activity, the major metabolic pathway for tramadol elimination, and was determined to be an extensive metabolizer with very high CYP2D6 activity.

CONCLUSIONS

The exact mechanism of the adverse response is not known; however, based on phenotyping results, we suspect that it may be related to high concentrations of the active O-desmethyl metabolite of tramadol.

Hematopoietic potential of cryopreserved and ex vivo manipulated umbilical cord blood progenitor cells evaluated in vitro and in vivo

The hematopoietic potential of cryopreserved and ex vivo manipulated umbilical cord blood (UCB) samples was evaluated in vitro and in vivo. Phenotypic analysis shows that approximately 1% of cord blood mononuclear cells express high levels of CD34 antigen on their surface (CD34hi), but none of a panel of lineage antigens (Lin-), suggesting that they are hematopoietic progenitor cells that have not yet committed to a specific lineage. Approximately 1% of CD34hi/Lin- cells are primitive hematopoietic progenitors that produce B lymphoid and multiple myeloid progeny for up to 7 weeks in stromal cell cultures. Twenty-one percent (+/- 13%) of CD34hi/Lin- cells also express low levels of the Thy-1 antigen and are threefold to fourfold enriched over CD34hi/Lin- cells in primitive hematopoietic potential as measured by long-term culture and phenotypic analysis. One-week liquid cultures of CD34-enriched UCB progenitor cells in the presence of interleukin (IL)-3, IL-6, and stem cell factor (SCF) results in a two-fold to threefold expansion of progenitors capable of reinitiating long-term stromal cell cultures. Only the CD34hi/Thy-1+/Lin- cell population was capable of maintaining progenitors with secondary transfer potential in long-term stromal cell cultures and is thus postulated to contain all of the primitive hematopoietic stem cells in UCB. The in vivo transplantation potential of UCB was also measured. Ex vivo manipulated UCB progenitor cells were used to engraft irradiated human thymus fragments implanted in severe combined immunodeficiency (SCID) mice. Thymic engraftment with >5% donor-derived cells and a normal CD4/CD8 distribution was observed in 19 of 23 tissues tested. UCB cells from in vitro expansion cultures engrafted with efficiencies comparable to nonexpanded cells. Similar results were obtained for UCB engraftment of human bone fragments implanted in SCID mice. In all cases, engraftment was achieved in competition with endogenous competitor stem cells and across major histocompatibility barriers. Taken together, this data demonstrates that human UCB is a rich source of multipotent hematopoietic progenitors that can be cryopreserved, enriched by physical methods, and expanded in a limited fashion without measurable loss of long-term culture or in vivo engrafting potential as measured in these assays.

Beta 3-endonexin, a novel polypeptide that interacts specifically with the cytoplasmic tail of the integrin beta 3 subunit

The adhesive and signaling functions of integrins are regulated through their cytoplasmic domains. We identified a novel 111 residue polypeptide, designated beta 3-endonexin, that interacted with the cytoplasmic tail of the beta 3 integrin subunit in a yeast two-hybrid system. This interaction is structurally specific, since it was reduced by 64% by a point mutation in the beta 3 cytoplasmic tail (S752-->P) that disrupts integrin signaling. Moreover, this interaction is integrin subunit specific since it was not observed with the cytoplasmic tails of the alpha IIb, beta 1, or beta 2 subunits. beta 3-Endonexin fusion proteins bound selectively to detergent-solubilized beta 3 from platelets and human umbilical vein endothelial cells, and beta 3-endonexin mRNA and protein were detected in platelets and other tissues. A related mRNA encoded a larger polypeptide that failed to bind to beta integrin tails. The apparent specificity of beta 3-endonexin for the beta 3 integrin subunit suggests potential mechanisms for selective modulation of integrin functions.

Determinants of specificity of a baculovirus-expressed antibody Fab fragment that binds selectively to the activated form of integrin alpha IIb beta 3

PAC1 is an IgM kappa murine monoclonal antibody that, like the Arg-Gly-Asp-containing ligand fibrinogen, binds to integrin alpha IIb beta 3 only on activated platelets. The unique binding properties of PAC1 may be determined by its large size, its multivalency, and by variable region sequences, including an Arg-Tyr-Asp at residues 100A-C in H-CDR3. To study the molecular determinants of PAC1 function, baculoviruses containing cloned cDNA for the Fd heavy and kappa light chains of PAC1 were used to co-infect Sf9 insect cells. Infected cells secreted a soluble, monovalent, 50-kDa Fab fragment that bound saturably to agonist-stimulated platelets but not to resting cells. Fab binding was inhibited > 85% by 10 mM EDTA, 1 mM RGDS, 1 mM fibrinogen gamma 397-411, or 12 microM fibrinogen, but not by 1 mM RGES. Compared to PAC1 IgM, a 60-fold higher molar concentration of PAC1 Fab was required for half-maximal binding to platelets or for half-maximal inhibition of fibrinogen binding. PAC1 Fab bound to an activated form of alpha IIb beta 3 expressed in Chinese hamster ovary cells, but not to the resting form of the receptor in these cells or to alpha v beta 3 in human endothelial cells. Conversion of Asp100C to Glu by site-directed mutagenesis rendered the antibody inactive, indicating that the Arg-Tyr-Asp sequence in H-CDR3 is essential for PAC1 recognition of alpha IIb beta 3. Binding of fibrinogen or PAC1 IgM to platelets induced tyrosine phosphorylation of a 140-kDa platelet protein, but binding of PAC1 Fab did not. These studies demonstrate that the specificity of PAC1 for activated alpha IIb beta 3 is determined by an integrin recognition sequence within H-CDR3. However, the strength of this binding interaction and the ability of PAC1 to trigger signaling in platelets also depend on antibody valency.

Contribution of occupation and diet to white blood cell polycyclic aromatic hydrocarbon-DNA adducts in wildland firefighters

Wildland (forest) firefighters are exposed to a wide range of carcinogenic polycyclic aromatic hydrocarbons (PAH) in forest fire smoke. PAH undergo metabolic activation and can subsequently bind to DNA. In this study, we investigated the association between occupational and dietary PAH exposures and the formation of WBC PAH-DNA adducts in a population of wildland firefighters. An enzyme-linked immunosorbent assay using an antiserum elicited against benzo(a)pyrene-modified DNA was used to measure PAH-DNA adducts in WBC obtained from 47 California firefighters at two time points, early and late in the 1988 forest fire season. PAH-DNA adduct levels were not associated with cumulative hours of recent firefighting activity. However, firefighters who consumed charbroiled food within the previous week had elevated PAH-DNA adduct levels, which were related to frequency of charbroiled food intake. These findings suggest that dietary sources of PAH contribute to PAH-DNA adduct levels in peripheral WBC and should be evaluated when using this assay to assess occupational and environmental PAH exposure.

Association of PAH-DNA adducts in peripheral white blood cells with dietary exposure to polyaromatic hydrocarbons

Previous investigations suggest that dietary sources of polycyclic aromatic hydrocarbons (PAHs) contribute to the PAH-DNA adduct load in peripheral white blood cells (WBCs). In the current study, we measured PAH-DNA adducts by enzyme-linked immunosorbent assay in WBCs obtained from 47 California wildland (forest) firefighters at two time points (early and late) during an active forest fire season. PAH-DNA adduct levels were not associated with recent firefighting activity, but were positively associated with frequency of charbroiled food consumption in the previous 2 weeks. In addition, adduct levels declined with time since last ingestion of charbroiled food. These studies indicate that recent consumption of charbroiled food contributes to the PAH-DNA adduct load in peripheral WBCs.

Molecular cloning and preliminary characterization of a novel cytoplasmic antigen recognized by myasthenia gravis sera

A cDNA clone was isolated by screening of a lambda gt11 endothelial expression library with serum from a patient with myasthenia gravis (MG). Rabbit antisera raised against the recombinant protein and human MG sera reactive with the clone immunoblotted an M(r) integral of 250,000 polypeptide (gravin) present in endothelial cells and several adherent cells. Gravin was not detected in platelets, leukocytes, U937, or human erythroleukemic (HEL) cell lines, but was expressed in HEL cells after induction with phorbol myristate acetate. Northern blot analysis showed two transcripts of approximately 6.7 and 8.4 kb in endothelial cells but not U937 or HEL cells. Indirect immunofluorescence of permeabilized cells revealed a trabecular network of gravin staining with a distinct linear component. Antibodies to gravin, were present in sera from 22:72 (31%) of MG patients. In contrast 0:50 normal sera and 1:72 sera from patients with other autoimmune diseases contained antigravin antibodies. Gravin is not likely to be a nonerythroid spectrin, talin, myosin, or actin-binding protein based on the lack of reactivity of antigravin with these polypeptides in immunoblots. The nucleotide sequence of the immunoreactive clone indicated that it encodes a highly acidic polypeptide fragment that contains the carboxyl terminus of the protein. Neither amino acid nor nucleotide sequences were present in Genbank, EMBL, or Swissprot databases as of March, 1992. These data indicate that gravin is an inducible, cell type-specific cytoplasmic protein and that auto-antibodies to gravin may be highly specific for MG.

Pulmonary function and respiratory symptoms in wildland firefighters

We studied cross-seasonal changes in pulmonary function and respiratory symptoms in 52 wildland firefighters in Northern California. The mean cross-seasonal change in forced expiratory volume in 1 second (FEV1) was -1.2% (95% confidence interval [CI] -0.5%, -2.0%) with a corresponding mean change in forced expiratory volume (FVC) of -0.3% (95% CI 0.4%, -1.0%). Decreases in FEV1 and FVC were most strongly associated with hours of recent fire-fighting activity (P = .002 and .01, respectively). When the study group was divided into three categories based on recent fire-fighting activity, firefighters in the high activity category (mean +/- SE, 73 +/- 7 hours of fire-fighting in previous week) had a -2.9% (130 mL) change in FEV1 and a -1.9% (102 mL) change in forced vital capacity (FVC). There was a significant cross-seasonal increase in most respiratory symptoms evaluated. Several symptoms (eye irritation, nose irritation, and wheezing) were associated with recent fire-fighting. These findings suggest that wildland firefighters experience a small cross-seasonal decline in pulmonary function and an increase in several respiratory symptoms. Research is under way to identify the fire conditions and specific components of exposure that produce pulmonary irritants, and to examine the potential reversibility of acute pulmonary change.

Release of early human hematopoietic progenitors from quiescence by antisense transforming growth factor beta 1 or Rb oligonucleotides

We have used antisense oligonucleotides to study the roles of transforming growth factor beta (TGF-beta) and the two antioncogenes, retinoblastoma susceptibility (Rb) and p53, in the negative regulation of proliferation of early hematopoietic cells in culture. The antisense TGF-beta sequence significantly enhanced the frequency of colony formation by multi-lineage, early erythroid, and granulomonocytic progenitors, but did not affect colony formation by late progenitors. Single cell culture and limiting dilution analysis indicated that autocrine TGF-beta is produced by a subpopulation of early progenitors. Antisense Rb but not antisense p53 yielded similar results in releasing multipotential progenitors (colony-forming unit-granulocyte/erythroid/macrophage/megakaryocyte) from quiescence. Rb antisense could partially reverse the inhibitory effect of exogenous TGF-beta. Anti-TGF-beta blocking antibodies, antisense TGF-beta, or Rb oligonucleotides all had similar effects. No additive effects were observed when these reagents were combined, suggesting a common pathway of action. Our results are consistent with the model that autocrine production of TGF-beta negatively regulates the cycling status of early hematopoietic progenitors through interaction with the Rb gene product.

Synergistic effects of the combination of cis-platinum diamminodichloride and 2,2'-anhydro-1-beta-D-arabinofuranosyl-5-fluorocytosine in transplanted mouse leukemias

cis-Platinum diamminodichloride has been studied in combination with 2,2'-anhydro-1-beta-D-arabinofuranosyl-5-fluorocytosine on an every-4-day schedule in various lines of mouse leukemia. This combination is synergistic in leukemias L1210 and P388 and sublines made resistant to 5-fluorouracil or methotrexate. There is no cross-resistance between cis-platinum diamminodichloride and 2,2'-anhydro-1-beta-D-arabinofuranosyl-5-fluorocytosine, but the combination is no more effective against lines of leukemia made resistant to cis-platinum diamminodichloride or to 2,2'-anhydro-1-beta-D-arabinofuranosyl-5-fluorocytosine than either single active compound alone. Since these compounds have no cross-resistance, act by quite different mechanisms of action, and have different limiting toxicity, the combination is now being evaluated clinically.

Lack of cross-resistance between certain platinum coordination compounds in mouse leukemia

Two congeners of cis-platinum diamminodichloride, 1,2-diamminocyclohexylplatinum malonate (NSC 224964) and 1,2-cyclohexyldiamminoplatinum sulfate (NSC 250427), show approximately equal inhibitory activity in vitro against leukemia L1210 and a line of L1210 (L1210/PDD) that has developed resistance to cis-platinum diamminodichloride. These compounds are also active against L1210/PDD in vivo. These observations suggest that they be tried clinically in patients whose disease has become resistant to cis-platinum diamminodichloride.

Antileukemic effects of pseudoisocytidine, a new synthetic pyrimidine C-nucleoside

Pseudoisocytidine, a new synthetic pyrimidine C-nucleoside, which might be considered a more stable analog of 5-azacytidine, is active in vitro and in vivo, i.p. and p.o., against various 1-beta-D-arabinofuranosylcytosine-resistant lines of mouse leukemia. This antileukemic activity is blocked by cytidine but not by deoxycytidine or thymidine.