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Biomedical subjects

S H Appel

Publications and source records attributed to S H Appel.

At least 91 records · Page 5Linked to original sources
PubMed1994

Cytotoxicity of immunoglobulins from amyotrophic lateral sclerosis patients on a hybrid motoneuron cell line.

Patients with amyotrophic lateral sclerosis possess antibodies (ALS IgGs) that bind to L-type skeletal muscle voltage-gated calcium channels (VGCCs) and inhibit L-type calcium current. To determine whether interaction of ALS IgGs with neuronal VGCCs might influence motoneuron survival, we used a motoneuron-neuroblastoma hybrid (VSC 4.1) cell line expressing binding sites for inhibitors of L-, N-, and P-type VGCCs. Using direct viable cell counts, quantitation of propidium iodide- and fluorescein diacetate-labeled cells, and lactate dehydrogenase release to assess cell survival, we document that ALS IgG kills 40-70% of cAMP-differentiated VSC 4.1 cells within 2 days. ALS IgG-mediated cytotoxicity is dependent on extracellular calcium and is prevented by peptide antagonists of N- or P-type VGCCs but not by dihydropyridine modulators of L-type VGCCs. Preincubating IgG with purified intact L-type VGCC or with isolated VGCC alpha 1 subunit also blocks ALS IgG-mediated cytotoxicity. These results suggest that ALS IgG may directly lead to motoneuron cell death by a mechanism requiring extracellular calcium and mediated by neuronal-type calcium channels.

Amyotrophic Lateral Sclerosis↗
PubMed1994

Attenuation of the neurotoxic effect of A beta amyloid peptide by apolipoprotein E.

Alzheimer's disease patients have increased frequency of apolipoprotein E allele c4, suggesting apoE4 is a risk factor determining disease. ApoE binds A beta amyloid peptide with great avidity in vitro and in the neuritic plaque. Potentially, binding of A beta to apolipoprotein E could increase A beta neurotoxicity. However, in hippocampal cultures, 0.1 microM apolipoprotein E eliminated the neurotoxicity of 10 microM A beta. Neuronal rescue was dose-dependent and occurred even after 48 hours exposure to A beta, but was overwhelmed by excess A beta. Thus, interaction between these proteins does not directly increase A beta neurotoxicity, and the role of ApoE in Alzheimer's disease remains to be elucidated.

Amyloid beta-Peptides↗
PubMed1994

Amyotrophic lateral sclerosis patient antibodies label Ca2+ channel alpha 1 subunit.

Sporadic amyotrophic lateral sclerosis is an idiopathic human degenerative disease of spinal cord and brain motor neurons. Prior studies demonstrated that most patients with amyotrophic lateral sclerosis possess immunoglobulins that bind to purified L-type voltage-gated calcium channels, that titers of anti-voltage-gated calcium channel antibodies correlate with disease progression rates, and that amyotrophic lateral sclerosis patient-derived antibodies (ALS IgG) produce electrophysiological changes in the function of voltage-gated calcium channels. Using Western transfer immunoblots and enzyme-linked immunosorbent assays, the calcium ionophore-forming alpha 1 subunit of the voltage-gated calcium channel is now identified as the major voltage-gated calcium channel antigen to which ALS IgG binds. Additionally, the binding of an L-type voltage-gated calcium channel alpha 1 subunit-directed monoclonal antibody, which itself mimics the effects of ALS IgG on skeletal muscle voltage-gated calcium channel currents, is selectively prevented by preaddition of ALS IgG. Voltage-gated calcium channel-binding IgG from patients with Lambert-Eaton myasthenic syndrome appears to be differentiated from ALS IgG by the reactivity of the former to both alpha 1 and beta subunits of the calcium channel. These assays provide further evidence linking amyotrophic lateral sclerosis to an autoimmune process, and suggest one means to differentiate immunoglobulins from patients with amyotrophic lateral sclerosis from those of patients with another autoimmune disease expressing calcium channel antibodies.

Amyotrophic Lateral Sclerosis↗
PubMed1994

The role of calcium-binding proteins in selective motoneuron vulnerability in amyotrophic lateral sclerosis.

The factors contributing to selective motoneuron loss in amyotrophic lateral sclerosis (ALS) remain undefined. To investigate whether calcium-binding proteins contribute to selective motoneuron vulnerability in ALS, we compared calbindin-D28K and parvalbumin immunoreactivity in motoneuron populations in human ALS, and in a ventral spinal cord hybrid cell line selectively vulnerable to the cytotoxic effects of ALS IgG. In human autopsy specimens, immunoreactive calbindin-D28k and parvalbumin were absent in motoneuron populations lost early in ALS (i.e., cortical and spinal motoneurons, lower cranial nerve motoneurons), while motoneurons damaged late or infrequently in the disease (i.e., Onuf's nucleus motoneurons, oculomotor, trochlear, and abducens nerve neurons) expressed markedly higher levels of immunoreactive calbindin-D28K and/or parvalbumin. Motoneuron-neuroblastoma VSC 4.1 hybrid cells lost immunoreactive calbindin-D28k and parvalbumin following dibutyryl-cyclic AMP-induced differentiation and were killed by IgG from ALS patients. Undifferentiated calbindin/parvalbumin-reactive VSC 4.1 cells were not killed, nor were other cell lines expressing high levels of calbindin-D28K and parvalbumin immunoreactivity (substantia nigra-neuroblastoma hybrid cells and N18TG2 neuroblastoma parent cells). These studies suggest that decreased calbindin-D28K and parvalbumin immunoreactivity may help explain the selective vulnerability of motoneurons in ALS.

Adult↗
PubMed1994

Decremental motor responses to repetitive nerve stimulation in ALS.

Repetitive nerve stimulation (RNS) of the trapezius muscle at slow rates was performed on 192 patients with amyotrophic lateral sclerosis (ALS). Fifty-six patients (29%) showed classical neuromuscular decrement of 10-43% (mean 16.8%) while 44 patients (23%) had a borderline decrement of 5-9%. The trapezius was significantly more sensitive in revealing the defect than the distal hypothenar muscles. In 30 patients followed serially, the decremental response remained constant or increased with time. However, 25% of patients continued to show no decrement in spite of progression of disease. No statistical correlation was found between decrement and clinical severity, disease staging, or disease progression. The finding that at least 50% of ALS patients show some degree of decrement on RNS of the trapezius muscle suggests that functional alterations of the neuromuscular junction accompany this disease.

Action Potentials↗
PubMed1994

Evidence for autoimmunity in amyotrophic lateral sclerosis.

Although the etiology and pathogenesis of ALS is unknown, increasing evidence supports a role for autoimmune mechanisms in motoneuron degeneration and death. An animal model, experimental autoimmune gray matter disease, can be induced by the inoculation of spinal cord gray matter. The experimental disease is characterized by weakness secondary to the loss of upper and lower motoneurons, accompanied by inflammatory foci within the spinal cord, and IgG at the neuromuscular junction and within UMN and LMN. In human ALS, IgG is present within the UMN and LMN, and T-lymphocytes and activated microglia have been identified within spinal cord gray matter and motor cortex. ALS IgG can passively transfer physiological changes of the neuromuscular junction to mice resulting in enhanced release of acetylcholine. The ALS IgG selectively interact with calcium channels and alter channel function. These data suggest a potential role for autoimmune mechanisms in the destruction and loss of motoneurons in ALS.

Amyotrophic Lateral Sclerosis↗
PubMed1994

Apoptotic cell death of a hybrid motoneuron cell line induced by immunoglobulins from patients with amyotrophic lateral sclerosis.

Apoptotic cell death has recently been implicated in diseases involving nonproliferating, terminally differentiated cells such as neurons. Previous experiments have documented that immunoglobulins from patients with amyotrophic lateral sclerosis (ALS) can kill motoneuron-neuroblastoma hybrid cells [ventral spinal cord 4.1 (VSC 4.1)] by a calcium-dependent process. Here, we studied the mechanism of ALS IgG-induced cell death. In the presence of ALS IgG the VSC 4.1 cells undergo cell shrinkage and membrane blebbing, which are morphological features of apoptotic cell death. The damaged cells can be identified by in situ end labeling of nicked DNA and biochemically show laddering on agarose gel electrophoresis. This ALS IgG-triggered process is prevented by cycloheximide, aurintricarboxylic acid, and zinc sulfate. These data demonstrate that immunoglobulins from patients with ALS are able to induce apoptosis in motoneuron hybrid cells and provide a potential mechanism for motoneuron degeneration in human ALS.

Aged↗
PubMed1994

Detection of intraabdominal abscess by serum lysozyme estimation.

BACKGROUND: The failure of new, innovative, and often expensive tests to show the presence of intraabdominal infection caused us to reexamine the value of an inexpensive and almost forgotten one. Lysozyme is a bacteriolytic enzyme located within the lysosomes of phagocytic cells including leukocytes. METHODS: We measured serum concentrations of lysozyme by a standard turbidimetric method in both a murine model of intraabdominal infection and in trauma patients with intraabdominal abscesses or other acquired infections. RESULTS: In mice with intraabdominal abscess secondary to cecal ligation and puncture (n = 35) serum lysozyme activity increased compared with sham-operated controls (n = 20; p < 0.001). In trauma patients with intraabdominal abscess after injury and surgery (n = 19), there was also an increase in serum lysozyme activity compared with controls (n = 15; p < 0.001) or with patients with lung infection (n = 21; p < 0.001). The increase of serum lysozyme activity occurred before intraabdominal sepsis was clinically apparent. CONCLUSIONS: In this study, serum lysozyme concentration has a high specificity related to the presence of an intraabdominal abscess and is an indirect measure of the sequestration of leukocytes to the site of an established or developing collection of intraabdominal pus. The estimation of serum lysozyme may be an aid to differentiate critically ill patients with a potential occult intraabdominal abscess.

Abdomen↗
PubMed1993

Modulation of acetylcholine release in rat hippocampus by amino alcohols and Bay K 8644.

The amino alcohols ethanolamine, R-alaninol and R-prolinol were shown to enhance high potassium evoked release of [3H]acetylcholine from hippocampal slices by monitoring fractional release of tritium during superfusion. This action appeared to be unique to hippocampal cholinergic nerve terminals because R-prolinol did not modulate evoked release of acetylcholine from cortical or striatal slices, dopamine from striatal slices or norepinephrine from hippocampal slices. Bay K 8644, a dihydropyridine activator of calcium L-channels, exhibited a similar specificity profile. Bay K 8644 decreased the EC50 of R-prolinol without changing the maximal response, indicating that the actions of these two compounds converge through a common cellular mechanism. The effect of R-prolinol was blocked by the L-channel antagonists diltiazem and verapamil but not by nifedipine. In contrast, nifedipine only and not diltiazem or verapamil, blocked the enhancement induced by Bay K 8644. It appears then that amino alcohols can modulate the release of acetylcholine in the hippocampus possibly by enhancing calcium entry into nerve terminals through a specific activation of presynaptic L-channels at a site other than that which interacts with dihydropyridines.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1993

Lymphocytic infiltrates in the spinal cord in amyotrophic lateral sclerosis.

OBJECTIVE: Immunohistochemical examination was undertaken to assess the presence of lymphocytes and lymphocyte subsets in the spinal cord in amyotrophic lateral sclerosis (ALS). DESIGN: Twenty-seven consecutive ALS autopsy cases and 11 consecutive disease--control autopsy cases were examined. Tissue sections were reacted with mouse monoclonal antibody to human leukocyte common antigen, or monoclonal antibody to human B-cell L26 antigen, and detected with immunoperoxidase techniques. Unfixed sections were reacted with antihuman Leu-3a and Leu-3b/CD4 or antihuman Leu-2a/CD8 mouse monoclonal antibody and then detected with peroxidase techniques. SETTING: Tertiary care hospital. CASES: Amyotrophic lateral sclerosis and non-ALS control autopsy specimens. MAIN OUTCOME MEASURE: Detection of lymphocytes by histological and immunohistochemical reactivity. RESULTS: Perivascular and intraparenchymal lymphocytic infiltrates were found in the spinal cord of 18 of 27 consecutive ALS autopsy cases. The lymphocytes possessed only T-cell markers; no B-cell markers could be demonstrated. T-helper cells were found in proximity to degenerating corticospinal tracts, while T-helper and T-suppressor/cytotoxic cells were demonstrated in ventral horns. Lymphocytes were present in the spinal cord of only one control specimen (multiple sclerosis) and in none of the remaining 10 control specimens. In ALS tissue, the lymphocytic infiltrates did not correlate with the rate of progression or stage of the disease or with the presence or absence of terminal infections. CONCLUSIONS: T-cell lymphocytes are present in the spinal cord of patients with ALS. T-helper cells are found in proximity to corticospinal tract degeneration, while T-helper and T-suppressor/cytotoxic cells are present in ventral horns. The role of these lymphocytes remains to be elucidated.

Adult↗
PubMed1993

Evidence for autoimmunity in amyotrophic lateral sclerosis.

Although the etiology and pathogenesis of ALS is unknown, increasing evidence supports a role for autoimmune mechanisms in motoneuron degeneration and death. An animal model, experimental autoimmune gray matter disease, can be induced by the inoculation of spinal cord gray matter. The experimental disease is characterized by weakness secondary to the loss of upper and lower motoneurons, accompanied by inflammatory foci within the spinal cord, and IgG at the neuromuscular junction and within UMN and LMN. In human ALS, IgG is present within the UMN and LMN, and T-lymphocytes and activated microglia have been identified within spinal cord gray matter and motor cortex. ALS IgG can passively transfer physiological changes of the neuromuscular junction to mice resulting in enhanced release of acetylcholine. The ALS IgG selectively interact with calcium channels and alter channel function. These data suggest a potential role for autoimmune mechanisms in the destruction and loss of motoneurons in ALS.

Amyotrophic Lateral Sclerosis↗
PubMed1993

Vimentin-crossreactive antibodies induce cell death in primary cultures of embryonic spinal cord.

Sera from guinea pigs inoculated with spinal cord gray matter were cytotoxic for embryonic day 14 (ED14) primary spinal cord cell cultures. All cell types including astroglia and neurons were affected. Immunoglobulin (IgG) from inoculated animals and biologically active complement proteins were both identified as necessary components for the observed cytotoxicity. Adsorption with cytoskeletal constituents removed the cytotoxic effect. Adsorption with purified vimentin substantially reduced cytotoxicity, while adsorption with glial fibrillary acid protein (GFAP) had no cytoprotective effects. Antiserum from vimentin-immunized guinea pigs was also toxic to spinal cord cell cultures. Antibody and complement-mediated toxicity appeared to result from interaction with vimentin bound to the surface of embryonic cultured glia and neurons, although interaction with a cross-reacting epitope could not be definitely excluded. Cytotoxic vimentin-directed antibody was not noted in control sera, and the presence of this antibody in guinea pig and human sera did not correlate with the clinicopathological state.

Adsorption↗
PubMed1993

Experimental immune-mediated motor neuron diseases: models for human ALS.

Amyotrophic lateral sclerosis is an idiopathic, ultimately fatal disease, clinically manifest as progressive weakness and spasticity, associated with the loss of motoneurons. Circumstantial evidence supports a role for autoimmune processes in the progression of this human disorder. Two immune-mediated animal models have been developed in our laboratory for motor neuron loss. Experimental autoimmune motor neuron disease is a lower motor syndrome induced in guinea pigs by the repeated injection of a purified bovine spinal motor neuron antigen. Affected animals demonstrate extremity weakness, associated with electromyographic and morphologic evidence of denervation, a loss of spinal cord motor neurons, high antibody titers against motor neurons, and localization of IgG immunoreactivity to the neuromuscular junction and motor neuron cytoplasm. Experimental autoimmune grey matter disease is a more acute and severe disorder involving both upper and lower motor neurons, induced in guinea pigs by inoculation of a bovine ventral spinal cord homogenate, in which scattered foci of denervation are observed in the motor cortex and ventral spinal cord. Similarities between these diseases and human ALS are reviewed.

Amyotrophic Lateral Sclerosis↗
PubMed1993

A biologic basis for altered host defenses in surgically infected abscesses.

OBJECTIVE: This study determines whether there are any differences in several immunologic parameters in circulating peripheral blood leukocytes, serum, and plasma compared with pus leukocytes, and supernatant of various types of abscess. SUMMARY BACKGROUND DATA: Although there have been reports of high lysozyme levels and low complement levels within pus, there has been no systemic comparison of concentrations of these substances and others within pus compared with those within peripheral blood. METHODS: Peripheral blood and abscess pus were collected from 31 patients with abscesses and percent and mean channel of monocytes expressing complement receptor and major histocompatibility antigen HLA-DR, the percent and mean channel of polymorphonuclear leukocytes (PMN) expressing complement receptor, lysozyme level, and levels of total hemolytic complement, iC3b, C5b-9, and immunoglobulins were measured within both pus and peripheral blood. RESULTS: Percent of monocytes expressing HLA-DR and percent of monocytes and PMN expressing complement receptor, total hemolytic complement, and IgM were reduced within pus compared with peripheral blood, whereas the mean channel of monocytes expressing HLA-DR and the mean channel of PMNs expressing CR3, C5b-9, and lysozyme were increased in pus. CONCLUSIONS: There are marked differences in immunologic parameters measured within pus of abscesses versus that seen in peripheral blood.

Abdomen↗
PubMed1993

The action of amyotrophic lateral sclerosis immunoglobulins on mammalian single skeletal muscle Ca2+ channels.

1. The planar phospholipid bilayer technique was used to study the T-tubule skeletal muscle dihydropyridine (DHP)-sensitive calcium (Ca2+) channel. To improve the signal-to-noise ratio, Ca2+ channel activity was recorded using both 800-50 and 500-50 mM NaCl gradients. 2. Ca2+ channels were characterized by their cation selectivity and pharmacological profile. The mean open time for channels identified by these techniques was increased by the DHP agonist Bay K 8644 (2 microM), while it was decreased by the DHP antagonist nifedipine (5 microM). Nifedipine also reduced Ca2+ channel amplitude levels. 3. Immunoglobulins G (IgG) from three amyotrophic lateral sclerosis (ALS) patients (n = 14 experiments), one myasthenia gravis (MG) patient (n = 3 experiments) and one healthy individual (n = 4 experiments), were tested on Ca2+ channel activity at a final concentration of 3 mg/ml. 4. Channel mean open time, mean closed time and time integral for the current were not modified by normal IgG (n = 4 experiments). Similarly, MG IgG did not reduce channel activity (n = 3 experiments). 5. ALS IgG reduced the mean open time of DHP-sensitive Ca2+ channel activity in twelve out of fourteen experiments. In addition, in five out of twelve experiments, ALS IgG stabilized the channel to a smaller amplitude level. 6. ALS IgG reduced Ca2+ channel activity in a side-selective fashion, probably corresponding to the external side of the channel. 7. These results suggest that ALS IgG action on DHP-sensitive Ca2+ channels is not mediated by second messengers, thus favouring a direct mechanism for interaction with the DHP receptor complex.

Amyotrophic Lateral Sclerosis↗