Morphological aspects of spinal cord autoimmune neuroprotection: colocalization of T cells with B7--2 (CD86) and prevention of cyst formation.
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Animals↗
Biomedical subjects
M Schwartz
Publications and source records attributed to M Schwartz.
Understanding physicians' intentions to withdraw from practice: the role of job satisfaction, job stress, mental and physical health.
Health care organizations may incur high costs due to a stressed, dissatisfied physician workforce. This study proposes and tests a model relating job stress to four intentions to withdraw from practice mediated by job satisfaction and perceptions of physical and mental health.
Adult↗
Congenital disorder of glycosylation type Ia (CDG-Ia): phenotypic spectrum of the R141H/F119L genotype.
AIMS: To delineate common and variable features and outcome of children with congenital disorder of glycosylation type Ia (CDG-Ia) caused by the frequent R141H/F119L PMM2 genotype. METHODS: Clinical data on 25 patients (mean age 7.6 years, range 0-19) were analysed. RESULTS: All patients had an early presentation with severe feeding problems and failure to thrive, hypotonia, hepatic dysfunction, inverted nipples, and abnormal subcutaneous fat pads. Eighteen patients were hospitalised in the neonatal period. Developmental delay was obvious before age 6 months. During the first seven months mean standard deviation score (SDS) for weight and length decreased 2.7 (SD = 2) and 2.4 (SD = 2), respectively. Mental retardation, ataxia, muscular atrophy, and febrile seizures were consistent features after infancy. Variable features included pericardial effusions, afebrile seizures, and stroke like episodes. Computed tomography/magnetic resonance imaging of the brain was normal in two patients examined before 4 months of age, but 18 children examined after 3 months of age had cerebellar atrophy, and 10 children also had supratentorial atrophy. Subsequent imaging showed progression of the cerebellar and supratentorial atrophy in eight and four of 10 children, respectively. Mean head circumference SDS declined from zero to -1.9 SD from age 3 months to 5 years. Motor ability ranged from none to walking with a rolator, and vocabulary ranged from none to comprehensible speech. The overall mortality ascribed to CDG-Ia was 18%. CONCLUSION: Patients with the R141H/F119L genotype have an early uniform presentation including severe failure to thrive, but their functional outcome is variable. This genotype may well cause clinical manifestations in the severe end of the spectrum of CDG-Ia.
Adolescent↗
Posttraumatic therapeutic vaccination with modified myelin self-antigen prevents complete paralysis while avoiding autoimmune disease.
Spinal cord injury results in a massive loss of neurons, and thus of function. We recently reported that passive transfer of autoimmune T cells directed against myelin-associated antigens provides acutely damaged spinal cords with effective neuroprotection. The therapeutic time window for the passive transfer of T cells was found to be at least 1 week. Here we show that posttraumatic T cell-based active vaccination is also neuroprotective. Immunization with myelin-associated antigens such as myelin basic protein (MBP) significantly promoted recovery after spinal cord contusion injury in the rat model. To reduce the risk of autoimmune disease while retaining the benefit of the immunization, we vaccinated the rats immediately after severe incomplete spinal cord injury with MBP-derived altered peptide ligands. Immunization with these peptides resulted in significant protection from neuronal loss and thus in a reduced extent of paralysis, assessed by an open-field behavioral test. Retrograde labeling of the rubrospinal tracts and magnetic resonance imaging supported the behavioral results. Further optimization of nonpathogenic myelin-derived peptides can be expected to lead the way to the development of an effective therapeutic vaccination protocol as a strategy for the prevention of total paralysis after incomplete spinal cord injury.
Adjuvants, Immunologic↗
Immunological approaches to the treatment of spinal cord injury.
The innate and adaptive arms of the immune system, represented principally by macrophages and by T and B cells, respectively, provide body tissues with mechanisms of defence, protection and repair. In the central nervous system (CNS), probably because of its status of 'immune privilege', any immune activity has long been viewed as detrimental. Recent studies have provided evidence, however, that immune activity after traumatic CNS injury may have a beneficial effect, manifested by promotion of regeneration and reduction in the secondary degeneration of neurons that escaped direct injury. Rigorous regulation of immune system activity allows the individual to derive the benefit of such neuroprotection without the risk of detrimental side effects. Recently, our research group found a way to boost the T-cell-mediated autoimmune protection while avoiding the risk of autoimmune disease.
Central Nervous System↗
Surrogate markers of antitumor responses: in vitro activation of T cells by autologous tumor peptides.
The increasing ability to augment antitumor immunity in model systems has led to increased numbers of clinical trials. However, progress in detecting immune responses by patients against autologous tumors has been slow. Although a considerable number of tumor antigens, as well as peptides derived from them, and the MHC determinants together with which they are presented have been identified for melanoma, this is not so for the majority of solid tumors. Furthermore, tumor cells themselves are poor stimulators of immunity. Thus, approaches that do not depend upon defined antigens or using tumor cells as stimulators would be desirable. To attempt to measure immune responses in these situations, we tested whether total peptides, prepared from autologous tumor tissue, stimulated cytokine release by T cells. Peripheral blood mononuclear cells (PBMCs) were mixed with antigen-presenting cells (APCs), pulsed with tumor peptides, and tested in the ELISPOT assay for IFN-gamma secretion. Few spots were obtained when PBMCs were cultured with unpulsed APCs or in wells with peptide-pulsed APC alone. In contrast, a strong response was seen when PBMCs were cultured with APCs that had been pulsed with autologous total tumor peptides. This system should help to identify those immunotherapeutic approaches that induce responses against tumor cells in vivo. Because different cytokine profiles are associated with distinct arms of the immune response, testing in the ELISPOT assay may also help us understand the mechanisms responsible.
Antigen-Presenting Cells↗
Evaluation of capillary electrophoresis performance through resolution measurements.
The application of resolution measurements to an electrophoretic system can give a quantitative analysis of the health of that system. Capillary electrophoresis has become a routine method for the analysis of DNA and resolution measurements can be used to assess the resulting electropherogram. A number of methods are available to evaluate resolution and three methods are detailed in the current work. Parameters such as polymer concentration and column length were also examined in terms of resolution, and changes therein, if these parameters were modified.
DNA↗
Detection of gamma-butyrolactone (GBL) as a natural component in wine.
The compound gamma-butyrolactone (GBL) was found in extracts from samples of unadulterated wines. This finding indicates that GBL is a naturally occurring component in some wines and may be present in similar products. The concentration detected was approximately 5 microg/mL and was easily observed using a simple extraction technique followed by GC/MS analysis. These results illustrate the need to carefully examine an allegedly adulterated sample's matrix before determining a sample was laced with GBL.
4-Butyrolactone↗
Cell adhesion regulates ubiquitin-mediated degradation of the platelet-derived growth factor receptor beta.
Cross-talk between integrin-mediated adhesion and growth factors has been described in many recent studies; however, the underlying mechanisms remain incompletely understood. We report here that detachment of cells from the extracellular matrix induced a decrease in both the autophosphorylation and protein levels of the platelet-derived growth factor receptor beta (PDGF-R beta), which was completely reversed upon replating cells on fibronectin. The effect occurred in all cells examined but to a greater extent in primary fibroblasts compared with established cell lines. Decreased PDGF-R levels in suspended cells correlated with ubiquitination of the PDGF-R and was blocked by treatment with inhibitors of the proteasome pathway. Unlike PDGF-induced down-regulation, detachment-induced degradation did not require receptor autophosphorylation, internalization, or tyrosine kinase activity. We conclude that cell detachment results in cellular desensitization to PDGF that is mediated by degradation of the PDGF-R via a novel ubiquitin-dependent pathway.
Adenoviridae↗
Passive or active immunization with myelin basic protein promotes recovery from spinal cord contusion.
Partial injury to the spinal cord can propagate itself, sometimes leading to paralysis attributable to degeneration of initially undamaged neurons. We demonstrated recently that autoimmune T cells directed against the CNS antigen myelin basic protein (MBP) reduce degeneration after optic nerve crush injury in rats. Here we show that not only transfer of T cells but also active immunization with MBP promotes recovery from spinal cord injury. Anesthetized adult Lewis rats subjected to spinal cord contusion at T7 or T9, using the New York University impactor, were injected systemically with anti-MBP T cells at the time of contusion or 1 week later. Another group of rats was immunized, 1 week before contusion, with MBP emulsified in incomplete Freund's adjuvant (IFA). Functional recovery was assessed in a randomized, double-blinded manner, using the open-field behavioral test of Basso, Beattie, and Bresnahan. The functional outcome of contusion at T7 differed from that at T9 (2.9+/-0.4, n = 25, compared with 8.3+/-0.4, n = 12; p<0.003). In both cases, a single T cell treatment resulted in significantly better recovery than that observed in control rats treated with T cells directed against the nonself antigen ovalbumin. Delayed treatment with T cells (1 week after contusion) resulted in significantly better recovery (7.0+/-1; n = 6) than that observed in control rats treated with PBS (2.0+/-0.8; n = 6; p<0.01; nonparametric ANOVA). Rats immunized with MBP obtained a recovery score of 6.1+/-0.8 (n = 6) compared with a score of 3.0+/-0.8 (n = 5; p<0.05) in control rats injected with PBS in IFA. Morphometric analysis, immunohistochemical staining, and diffusion anisotropy magnetic resonance imaging showed that the behavioral outcome was correlated with tissue preservation. The results suggest that T cell-mediated immune activity, achieved by either adoptive transfer or active immunization, enhances recovery from spinal cord injury by conferring effective neuroprotection. The autoimmune T cells, once reactivated at the lesion site through recognition of their specific antigen, are a potential source of various protective factors whose production is locally regulated.
Animals↗
IFNgamma secretion following stimulation with total tumor peptides from autologous human tumors.
Several issues remain to be resolved before the efficacy of various approaches to elicit anti-tumor immunity in patients can be evaluated. First, in vitro assays able to detect responses by T cells primed in vivo are needed. Second, a source of tumor antigen to stimulate patients' lymphocytes in vitro is required. The ELISPOT assay is attractive, because it can be performed with a small numbers of cells and requires only short-term culture in vitro. A source of tumor antigen is more problematic, since for most tumors, tumor-associated antigens (TAA) have not been identified and/or cloned. In this report we demonstrate that autologous antigen-presenting cells (APC) pulsed with total tumor peptides from autologous tumor tissue can stimulate IFNgamma release by patients' lymphocytes in the ELISPOT assay. Thus, this approach should be considered for monitoring immune responses in clinical immunotherapy trials.
Antigen Presentation↗
Autoimmune T cells retard the loss of function in injured rat optic nerves.
We recently demonstrated that autoimmune T cells protect neurons from secondary degeneration after central nervous system (CNS) axotomy in rats. Here we show, using both morphological and electrophysiological analyses, that the neuroprotection is long-lasting and is manifested functionally. After partial crush injury of the rat optic nerve, systemic injection of autoimmune T cells specific to myelin basic protein significantly diminished the loss of retinal ganglion cells and conducting axons, and significantly retarded the loss of the visual response evoked by light stimulation. These results support our challenge to the traditional concept of autoimmunity as always harmful, and suggest that in certain situations T cell autoimmunity may actually be beneficial. It might be possible to employ T cell intervention to slow down functional loss in the injured CNS.
Animals↗
T cell immunity to copolymer 1 confers neuroprotection on the damaged optic nerve: possible therapy for optic neuropathies.
We recently reported that the posttraumatic spread of degeneration in the damaged optic nerve can be attenuated by the adoptive transfer of autoimmune T cells specific to myelin basic protein. However, it would be desirable to obtain immune neuroprotection free of any possible autoimmune disease. In an attempt to obtain disease-free immune neuroprotection, we used the synthetic four-amino acid polymer copolymer 1 (Cop-1), which is known not to be encephalitogenic despite its cross-reactivity with myelin basic protein. We show here that active immunization with Cop-1 administered in adjuvant, as well as adoptive transfer of T cells reactive to Cop-1, can inhibit the progression of secondary degeneration after crush injury of the rat optic nerve. These results have implications for the treatment of optic neuropathies.
Animals↗
High incidence of propionic acidemia in greenland is due to a prevalent mutation, 1540insCCC, in the gene for the beta-subunit of propionyl CoA carboxylase.
Propionyl CoA carboxylase (PCC) is a mitochondrial, biotin-dependent enzyme involved in the catabolism of amino acids, odd-chain fatty acids, and other metabolites. PCC consists of two subunits, alpha and beta, encoded by the PCCA and PCCB genes, respectively. Inherited PCC deficiency due to mutations in either gene results in propionic acidemia (PA), an autosomal recessive disease. Surprisingly, PA is highly prevalent among Inuits in Greenland. We have analyzed reverse transcriptase-PCR products of the beta-subunit mRNA, to characterize the responsible mutation(s). A 3-bp insertion, 1540insCCC, was found in homozygous form in three patients and in compound heterozygous form in one patient. The resulting PCC has no measurable activity, and the mutant beta-subunit appears to be very unstable. To test the hypothesis that a common mutation is responsible for PA in the Greenlandic Inuit population, 310 anonymous DNA samples of Inuit origin were screened for 1540insCCC. We found a carrier frequency of 5%, which is very high compared with those of most other autosomal recessive diseases. Analysis of alleles of a very closely linked marker, D3S2453, revealed a high degree of linkage disequilibrium between one specific allele and 1540insCCC, suggesting that this mutation may be a founder mutation.
Alleles↗
Gemcitabine and vinorelbine in advanced nonsmall cell lung carcinoma: a phase II study.
BACKGROUND: The authors conducted a Phase II study to evaluate the activity of the combination of gemcitabine and vinorelbine in patients with advanced nonsmall cell lung carcinoma (NSCLC). METHODS: Patients were eligible if they had Stage IIIB (malignant pleural effusion) or Stage IV NSCLC, no prior chemotherapy, and Cancer and Leukemia Group B performance status (PS) 0-2. Patients with brain metastases were eligible if they were neurologically stable after brain irradiation. Thirty-three patients from participating institutions were enrolled. One patient was ineligible due to untreated brain metastases. Patients were treated with gemcitabine 1250 mg/m(2) over 30 minutes (1000 mg/m(2) for the first 6 patients) and vinorelbine 25 mg/m(2) over 6 minutes, both administered intravenously on Days 1 and 8 every 21 days. Treatment was planned for a total of six cycles or more if the patient had persistent benefit. Growth factors were not allowed. RESULTS: Among all 32 eligible patients, there were 8 partial responses, for an overall response rate of 25% (95% confidence interval [CI], 11.5-43. 4%). The median survival time was 8.3 months and the 1-year survival rate was 38% (95% CI, 24-59%). Patients with PS 0-1 had a median survival of 11.7 months and a 1-year survival rate of 48%. Grade 3 and 4 neutropenia was observed in 13% and 25% of the 148 treatment cycles, respectively. One patient died of neutropenic sepsis. Only 2 episodes of Grade 3 and 4 thrombocytopenia were observed. Nonhematologic toxicity was minimal. CONCLUSIONS: Gemcitabine and vinorelbine is an active and well-tolerated regimen in patients with advanced NSCLC, with response and survival rates at least comparable to those achieved with standard platinum-based regimens. This combination may be particularly suitable for the elderly or for patients who cannot tolerate more toxic platinum-based regimens.
Aged↗
Autoimmune T cells as potential neuroprotective therapy for spinal cord injury.
Autoimmune T cells against central nervous system myelin associated peptide reduce the spread of damage and promote recovery in injured rat spinal cord, findings that might lead to neuroprotective cell therapy without risk of autoimmune disease.
Animals↗
Mutations in PMM2 that cause congenital disorders of glycosylation, type Ia (CDG-Ia).
The PMM2 gene, which is defective in CDG-Ia, was cloned three years ago [Matthijs et al., 1997b]. Several publications list PMM2 mutations [Matthijs et al., 1997b, 1998; Kjaergaard et al., 1998, 1999; Bjursell et al., 1998, 2000; Imtiaz et al., 2000] and a few mutations have appeared in case reports or abstracts [Crosby et al., 1999; Kondo et al., 1999; Krasnewich et al., 1999; Mizugishi et al., 1999; Vuillaumier-Barrot et al., 1999, 2000b]. However, the number of molecularly characterized cases is steadily increasing and many new mutations may never make it to the literature. Therefore, we decided to collate data from six research and diagnostic laboratories that have committed themselves to a systematic search for PMM2 mutations. In total we list 58 different mutations found in 249 patients from 23 countries. We have also collected demographic data and registered the number of deceased patients. The documentation of the genotype-phenotype correlation is certainly valuable, but is out of the scope of this molecular update. The list of mutations will also be available online (URL: http://www.kuleuven. ac.be/med/cdg) and investigators are invited to submit new data to this PMM2 mutation database.
Adolescent↗
CNS melanocortin system involvement in the regulation of food intake.
Accumulating evidence indicates that the central melanocortin (MC) system plays a key role in the regulation of food intake and energy balance. This evidence includes findings that either spontaneous genetic mutations or targeted gene deletions that impair melanocortin signaling cause disrupted food intake and body-weight control. In addition, expression of the mRNA that encodes the endogenous agonists and antagonists for CNS melanocortin receptors is regulated by changes in energy balance and body-adiposity signals. Finally, administration of both natural and synthetic ligands to MC receptors produces changes in food intake. The data collectively suggest a critical role for melanocortin signaling in the control of energy balance.
Animals↗