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Biomedical subjects

D Maimone

Publications and source records attributed to D Maimone.

34 records · Page 2Linked to original sources
PubMed1992

MK-801 protects retinal neurons from hypoxia and the toxicity of glutamate and aspartate.

The protective effect of the anticonvulsant MK-801 and the antitussive dextromethorphan, which are both N-methyl-D-aspartate receptor antagonists, and kynurenic acid, a broad-spectrum excitotoxin antagonist, was tested in cultured rat retinal cells in an hypoxic environment. The protective effect of these antagonists also was tested in cultured retinal cells and in intact adult rat retinas exposed to the exogenous excitotoxins L-glutamic acid and N-methyl-D-aspartic acid. MK-801 and kynurenic acid protected retinal neurons from hypoxic damage and from the toxicity of exogenous L-glutamic acid and N-methyl-D-aspartic acid. Dextromethorphan, a less potent antagonist, did not protect the retinal neurons from hypoxic damage or the toxicity of exogenous L-glutamic acid, but did attenuate N-methyl-D-aspartate toxicity. These results provide evidence that the synaptic release of excitatory transmitters, most likely glutamate and aspartate, mediate the death of hypoxic retinal neurons. Compounds related to MK-801 may have possible therapeutic applications in the management of retinal ischemia.

Animals↗
PubMed1991

Internal capsule plaque and tonic spasms in multiple sclerosis.

A patient developed hemilateral tonic spasms associated with a relapse of multiple sclerosis. An area of demyelination in the right internal capsule was observed on a magnetic resonance imaging scan. This lesion was not detectable on a second magnetic resonance imaging scan 10 months after the spasms had ceased. Paroxysmal symptoms in multiple sclerosis may represent transient phenomena related to inflammation in acute plaques.

Adult↗
PubMed1991

Cytokine levels in the cerebrospinal fluid and serum of patients with multiple sclerosis.

Interleukin (IL) 1 beta, tumor necrosis factor alpha (TNF alpha), and IL-6 are cytokines which mediate cellular responses during immune activation and inflammation. In multiple sclerosis (MS) they might be responsible for T-cell activation (IL-1 beta), for demyelination (TNF alpha), and for immunoglobulin (Ig) synthesis (IL-6) within the central nervous system. We studied IL-1 beta, TNF alpha, and IL-6 levels in the cerebrospinal fluid (CSF) of 34 patients with MS, 43 patients with non-inflammatory neurological diseases (NIND), and 19 patients with inflammatory neurological diseases (IND). IL-6 was found in the CSF of 29% of MS, 7% of NIND, and 47% of IND patients. TNF alpha was detected in the CSF of 23% of MS, 7% of NIND, and 29% of IND. CSF IL-6 and TNF alpha levels were significantly higher in MS and IND than in NIND. IL-1 beta was rarely detected in the CSF of any group. At least one cytokine was detected in 52% of MS CSF, 11% of NIND CSF, and 64% of IND CSF. In MS patients, no relationship was observed between the incidence or the amount of intrathecal IgG synthesis or oligoclonal bands and the presence of any cytokine. We also evaluated cytokine levels in paired sera from 11 MS and 13 NIND patients. Low levels of IL-6 were detected in most sera from MS and NIND patients. TNF alpha was detected in only two MS sera, and IL-1 beta was undetectable in any sample. Our results indicate that increased CSF levels of the cytokines IL-6 and TNF alpha occur frequently in MS and IND, but there is no obvious relationship to intrathecal Ig synthesis.

Adult↗
PubMed1991

Kappa light chain predominance in serum and cerebrospinal fluid from human immunodeficiency virus type 1 (HIV-1)-infected patients.

We measured kappa/lambda light chain ratios of Ig and IgG in 41 serum and 34 cerebrospinal fluid (CSF) samples from 47 patients at different clinical stages of human immunodeficiency virus type 1 (HIV-1) infection and in serum and CSF samples from control subjects. Both ratios were more elevated in HIV-1 seropositive subjects than controls. The elevation was more evident in samples from asymptomatic seropositive patients (ASP) than those from patients with acquired immunodeficiency syndrome (AIDS). In addition, there was a statistically significant elevation of Ig kappa/lambda ratios in ASP CSF compared to serum. We also delineated the light chain composition of oligoclonal IgG bands (OCB) by isoelectric focusing followed by immunofixation in CSF and serum samples from selected ASP and patients with AIDS who had neurological involvement. Five of six AIDS and all seven ASP samples had IgG OCB exclusively or predominantly of the kappa type. Four IgG OCB of the lambda type and one free lambda chain band were seen in CSF from a pediatric AIDS patient. The presence of an abnormally elevated kappa/lambda ratio correlated with the presence of IgG kappa OCB (p less than 0.02). We conclude that HIV-1 infection is associated with a kappa light chain predominance and with OCB mainly composed of kappa light chains.

Acquired Immunodeficiency Syndrome↗
PubMed1991

The function of the CD2 protein is abnormal in multiple sclerosis.

In active multiple sclerosis (MS), T cell adhesion to sheep red blood cells (SRBC) is deficient. The CD2 protein mediates adhesion to SRBC. Since ligands that bind CD2 can activate T cells, we studied adhesion and activation through CD2 in leukocytes from MS patients. Mononuclear cells (MNC) from patients with MS formed markedly fewer avid T cells (TA; T cells binding greater than or equal to 10 SRBC) than MNC from controls. CD2 antigen expression as measured by FACS analysis on T cells and on T cell subsets was equivalent in MS and controls and rose to a comparable extent in both groups after cell activation; yet activated MS MNC continued to form fewer TA than control cells. Avid rosette formation may be reduced by prostaglandins (PG) secreted by monocytes. Exposure to PG in vitro decreased TA% only in controls, suggesting refractoriness to exogenous PG in MS, perhaps because endogenous PG had already acted. The finding that indomethacin increased TA in MS cells favors this formulation. MNC were activated through CD2 using mAb 9-1 paired with mAb 9.6. Proliferation was significantly diminished in MNC from MS patients compared to MNC from normal controls. Thus, even though T cell membrane expression of CD2 appeared normal in MS, adhesion to SRBC and activation through the CD2 protein were defective.

Alprostadil↗
PubMed1991

Interferon-gamma and tumour necrosis factor induce expression of major histocompatibility complex antigen on rat retinal astrocytes.

Cultured rat retinal astrocytes were tested by indirect immunofluorescence staining for their ability to express class I and II major histocompatibility complex (MHC) antigens under basal culture conditions and after three days of stimulation with two recombinant cytokines, rat interferon-gamma (IFN-gamma) and human tumour necrosis factor alpha (TNF alpha). Under basal culture conditions low levels of class I antigens were detected on a small percentage of cells, but there was no visible class II. IFN-gamma and TNF alpha stimulation enhanced class I expression. TNF alpha had no effect on class II expression, whereas IFN-gamma induced the expression of class II in a dose dependent manner. These findings suggest that retinal astrocytes might play a part in immunological events occurring in the retina.

Animals↗
PubMed1991

Soluble CD8 levels in the CSF and serum of patients with multiple sclerosis.

CD8 is a membrane glycoprotein of 34 kd on cytotoxic/suppressor T lymphocytes and is an endogenous ligand for MHC class I proteins on target cells. CD8 is released in a soluble form upon T-lymphocyte activation. In multiple sclerosis (MS), T lymphocytes exhibit decreased membrane expression of the CD8 molecule and defective suppressor function. We measured soluble CD8 (sCD8) levels in the CSF of patients with MS, other inflammatory neurologic diseases (INDs), and noninflammatory neurologic diseases (NINDs). sCD8 levels in the CSF of MS and IND patients were elevated compared with NIND patients. Patients with acute infections of the CNS showed the highest absolute values of sCD8, but the amount of sCD8 per CSF white blood cell was greatest in MS and NIND patients. We found no difference in serum sCD8 levels among the groups. In MS, the combination of increased CSF sCD8 levels and sCD8 per cell may reflect CD8 T-lymphocyte activation within the brain or immunodysregulation confined to the CNS.

Antigens, CD↗
PubMed1988

Intrathecal interferon in subacute sclerosing panencephalitis.

Three patients at Stage II of subacute sclerosing panencephalitis (SSPE) were treated with semipurified alpha-interferon (IFN) using different combinations of intrathecal and intravenous routes: 1 x 10(6) IU of alpha-IFN were given every other day up to a total of 15 x 10(6) IU. Transient improvement of neurological symptoms and electroencephalogram were noted in all 3, while cognitive function slightly improved in 2 of them. Clinical benefits gradually disappeared 2 to 6 months after cessation of IFN. Intrathecal antibody production did not change substantially, but CSF Leu 3a/Leu 2a ratio appeared to increase. No significant side effects were observed, except for a mild meningeal inflammatory reaction after each intrathecal administration of IFN.

Adolescent↗
PubMed1986

IgG1,3 and 4 oligoclonal bands in multiple sclerosis and other neurological diseases.

Cerebrospinal fluid (CSF) samples from 10 patients with Multiple Sclerosis (MS) and 7 with other neurological diseases (OND) were studied in order to detect oligoclonal restriction of IgG subclasses 1,3 and 4. Agarose isoelectric focusing (AGA-IEF) followed by Western capillary blotting and immunoperoxidase staining with specific monoclonal antibodies were used. All MS samples showed oligoclonal IgG1 and 6 of them also had IgG3 or IgG4 bands. In the OND group only patients with subacute sclerosing panencephalitis (SSPE) and Guillain-Barré disease (GBD) showed CSF oligoclonal patterns for IgG subclasses. Our results demonstrate that in MS CSF other IgG subclasses beside IgG1 may display an oligoclonal pattern. The finding of more than one subclass in the same band indicates a microheterogeneous composition of these oligoclonal bands.

Adolescent↗
PubMedDate not supplied

[Therapy of subacute sclerosing panencephalitis with intrathecal alpha-interferon].

Clinical benefits were noted in subacute sclerosing panencephalitis patients treated with a total of 15 x 10(6) I.U. of alpha-interferon administered intrathecally over a period of one month. Improvements did not correlate with major variations in anti-measles IgG titers or variation of pattern, IgG subclass or light chain composition of CSF oligoclonal bands.

Adolescent↗