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Biomedical subjects

O Cohen

Publications and source records attributed to O Cohen.

At least 127 records · Page 7Linked to original sources
PubMed1987

Formation of heterotypic adherens-type junctions between L-CAM-containing liver cells and A-CAM-containing lens cells.

Cultured cells from either chicken lens or liver plated on solid substrates form flat epithelial sheets with adherens-type junctions between them. In lens cells these junctions contain A-CAM, while the same type of intercellular junctions in liver cells contain another cell adhesion molecule, L-CAM. Coculturing of lens and liver cells in the same dish resulted in the formation of mixed (heterotypic) adherens junctions. Double immunofluorescent labeling for both A-CAM and L-CAM indicated that the mixed junctions contained both molecules, each of which was present on one of the two partner cells. Moreover, the formation of the heterotypic junctions could be effectively inhibited by both anti-A-CAM and anti-L-CAM antibodies. It has thus been proposed that A-CAM and L-CAM share significant functional homology and may be involved in heterophilic interactions leading to the establishment of molecularly and cellularly asymmetrical adherens-type junctions.

Animals↗
PubMed1987

Carcinoma of the prostate presenting as interstitial lung disease.

Two patients were hospitalized because of fever, cough and dyspnea and an interstitial infiltrate of both lungs that was shown to be a lymphangitic spread of prostate carcinoma. The presentation of prostatic carcinoma as interstitial lung disease is rare, and emphasizes the importance of rectal examination and determination of acid phosphatase in the context of interstitial lung disease.

Adenocarcinoma↗
PubMed1986

Systemic administration of antioxidants does not protect mice against the dopaminergic neurotoxicity of 1-methyl-4-phenyl-1,2,5,6-tetrahydropyridine (MPTP).

We examined whether DA neurotoxicity of 1-methyl-4-phenyl-1,2,5,6-tetrahydropyridine (MPTP) can be prevented by combined systemic administration of antioxidants. C57 black mice were injected s.c. with MPTP (30 mg/kg), once daily for two days, alone, or with ascorbic acid (1 g/kg), alpha-tocopherol (100 mg/kg), or dimethylsulfoxide (50 microliters) i.p. for two days before, two days with and two days after MPTP, and decapitated 30 days later. MPTP once (30 mg/kg), alone, or with ascorbic acid (200 mg/kg) or cysteamine (75 mg/kg), two days before, one day with and 4 days after, and decapitated 10 days post-MPTP. MPTP once (15 mg/kg), alone, or with ascorbic acid (500 mg/kg, alpha-tocopherol (100 mg/kg), cysteamine (50 mg/kg) or sodium selenite (2.5 mg/kg), 90 min before and again 90 min after MPTP, and decapitated 7 days later. In all experiments, the marked striatal DA depletions produced by MPTP alone (by 40-70% from controls) were unchanged by cotreatments with the various antioxidants. Findings do not favor intraneuronal generation of superoxides and related cytotoxic free radicals as a major factor in the DA neurotoxicity of MPTP. They suggest that if natural Parkinson's disease is caused by an MPTP-like neurotoxin, early treatment with antioxidants is unlikely to protect nigrostriatal neurons and prevent disease progression.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1985

Dopamine but not norepinephrine or serotonin uptake inhibitors protect mice against neurotoxicity of MPTP.

Combined administration of nomifensine, a DA reuptake inhibitor, and MPTP completely prevented the long-term (30 days post-treatment) striatal DA depletions induced by MPTP in mice. Cotreatment with desipramine and clomipramine or fluoxetine, inhibitors of NE and 5-HT, respectively had no effect on DA neurotoxicity of MPTP. The findings indicate that MPTP (or MPP+) is a substrate for the specific DA reuptake system and may explain, in part, its selective toxic effects on DA neurons.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1985

Suppression of MPTP-induced dopaminergic neurotoxicity in mice by nomifensine and L-DOPA.

To examine effects of various pharmacological manipulations of dopamine (DA) metabolism on DA neurotoxicity of N-methyl-4-phenyl-1,2,5,6-tetrahydropyridine (MPTP), C57 black mice were injected with MPTP (30 mg/kg s.c., once daily for two days) alone or in combination with apomorphine, bromocriptine, haloperidol, L-DOPA or nomifensine. MPTP markedly decreased neostriatal DA concentrations at 2, 10, 20 and 30 days post-treatment indicating persistent degeneration of nigrostriatal DA neurons. Suppression or acceleration of DA turnover rates by the DA agonists apomorphine and bromocriptine or by the DA antagonist haloperidol, respectively, did not affect MPTP toxicity. MPTP-induced neostriatal DA depletions were markedly suppressed by nomifensine, a DA reuptake inhibitor, and attenuated by exogenous L-DOPA. MPTP may be a substrate for the DA reuptake system and its specific transport into nigrostriatal terminals may be an important factor for its selective neurotoxicity.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1985

Mesolimbic dopaminergic neurons are not spared by MPTP neurotoxicity in mice.

In C57 black mice, MPTP (N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) (30 mg/kg X 2, 20 mg/kg X 15, 30 mg/kg X 15, or 35 mg/kg X 1) depleted DA in both striatum and accumbens but not in frontal cortex, hypothalamus and retina. DA decreases were more pronounced in striatum than in accumbens, were maximal at 2 days, partially reversed later but persisted up to 30 days after treatment. DA depletions in nigra were smaller earlier and maximal later. The study suggests that, in mice, MPTP damages nigrostriatal and mesolimbic projections but spares other DA neurons.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1985

Amphetamine, but not reserpine, protects mice against dopaminergic neurotoxicity of MPTP.

In mice, long-term reductions in striatal DA produced by the neurotoxin MPTP were completely prevented by its combined administration with amphetamine. Depletion of DA from DA terminals by cotreatment with reserpine did not suppress but rather enhanced MPTP-induced DA decrements in striatum. Amphetamine protection against DA neurotoxicity of MPTP in mice is probably not due to increases in DA release and may be related to inhibition of MPTP transport into nigrostriatal terminals via the DA reuptake system.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1984

Immunological expression of gangliosides in multiple sclerosis and in a demyelinating model disease in rabbits.

Accumulating evidence suggests that the process of demyelination in MS might involve an autoimmune response to one or more myelin components. A combination of myelin basic protein and myelin haptens was considered as possibly enhancing a cellular or humoral autoimmune reaction in MS. In line with this motion we have used an in-vitro E-rosette assay that correlates with in-vivo delayed hypersensitivity to demonstrate specific immunologic sensitivity of lymphocytes from MS patients to polysialogangliosides. A recent report that only lymphocytes from patients in relapse, but not in remission, are primed by gangliosides, underscores the relevance of the antigenic expression of gangliosides during the active pathological phase of the disease. The antigenic capacity of gangliosides to induce upon immunization a neurological disorder featured by demyelination in the CNS was demonstrated in rabbits. This and previous reports on the induction of peripheral demyelination in rabbits immunized with gangliosides will be further analyzed to gain insight on the possible role of these myelin lipid components as targets for an autoimmune mechanism in MS.

Adult↗
PubMed1984

Class II HLA-DC beta-chain DNA restriction fragments differentiate among HLA-DR2 individuals in insulin-dependent diabetes and multiple sclerosis.

HLA-DR2 allele is negatively associated with insulin-dependent diabetes and positively associated with multiple sclerosis (MS). A 2.2-kilobase-pair EcoRI DNA restriction fragment detected with a beta-chain HLA-DC cDNA probe was found to be strongly correlated with HLA-DR2 in the normal population, but was absent in HLA-DR2 insulin-dependent diabetic patients. This fragment was found in HLA-DR2 multiple sclerosis patients with the same frequency as in controls. A beta-chain HLA-DC 12-kilobase-pair BamHI fragment might differentiate multiple sclerosis patients from healthy individuals.

DNA Restriction Enzymes↗
PubMed1984

Is predisposition to pemphigus vulgaris in Jewish patients mediated by HLA-Dw10 and DR4?

Twenty-one Israeli Jewish pemphigus vulgaris (PV) patients were studied for the HLA-D lymphocyte defined determinants and the serologically defined antigens of the HLA-A, B, and DR series. HLA-D typing revealed that Dw10 is significantly associated with PV: 86% of patients vs 18% of controls carried Dw10, and DR4 was present in 86% of patients as compared to 38% in the controls. The most striking observation was that all Dw10 positive patients were also positive for DR4, and no other patient carried DR4 alone. The relative risk for a Dw10-DR4 carrier to develop PV was estimated at 31.9, higher than that observed for Dw10 alone (RR 26.7) or DR4 alone (RR 9.6). Probably HLA-Dw10 predisposes for pemphigus vulgaris.

Epitopes↗