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Biomedical subjects

E Friedman

Publications and source records attributed to E Friedman.

At least 433 records · Page 24Linked to original sources

Myelination by transplanted fetal and neonatal oligodendrocytes in a dysmyelinating mutant.

Demyelination is a major feature of CNS injury and disease, including multiple sclerosis. To examine the potential for myelination by transplanted oligodendrocytes, initially described by Gumpel et al., we have transplanted neonatal cortex of mice with normal myelin into a dysmyelinating mutant, the shiverer mouse. We have found that oligodendrocyte precursors mature and synthesize myelin following transplantation. Immunostaining with antibodies to myelin basic protein (MBP), neurofilament protein and glial fibrillary acidic protein, demonstrates myelination both within the graft and extending out into the host, axonal sprouting from the graft which parallels the MBP-reactivity, and minimal astrocytic proliferation in response to the transplant.

Animals↗

The effect of imipramine treatment on brain serotonin receptors and beta-adrenoceptors and on pineal beta-adrenergic function in adult and aged rats.

The effect of age and of imipramine treatment on cortical serotonin and beta-adrenergic binding sites and on pineal N-acetylserotonin and melatonin were examined in Fischer-344 rats. Cortical serotonin-1 and -2 receptor binding was reduced by 15 and 22.5% respectively, in 24 vs. 6 months old animals. Ten single daily imipramine (10 mg/kg) injections in the aged animals resulted in reductions in both types of serotonin sites, while in adult animals significant binding reduction occurred only at the 5HT2 site. Cortical beta-adrenoceptor binding was also diminished in the aged rats. Imipramine treatment elicited a significantly greater decrease in these adrenergic sites in the aged (39.2%) than in the adult (27.6%) animals. In the pineal gland, N-acetylserotonin and melatonin content were reduced by age; imipramine treatment induced decreases in both indoles in the adult animals and a reduction in N-acetylserotonin in the aged animals. These age-related effects of imipramine on cortical serotonin receptor and beta-adrenoceptor binding and on pineal indoles may be a consequence of the higher drug and metabolite (desmethylimipramine) blood and tissue concentrations which were found in the aged animals.

Aging↗

Streptococcus bovis bacteremia and underlying gastrointestinal neoplasms.

Two patients are described in whom Streptococcus bovis bacteremia was the only clue to the presence of a colonic neoplasm. A third patient had the rare association of gastric carcinoma and Streptococcus bovis bacteremia that followed an operation for the carcinoma. The need for both complete gastrointestinal survey in patients with Streptococcus bovis bacteremia and administration of appropriate antibiotic prophylaxis during surgical manipulation is emphasized.

Aged↗

Comparative efficacy and safety of MAOIs versus TCAs in treating depression in the elderly.

This comprehensive study investigated both the role of antidepressant drugs in the treatment of affective disorders of later life and their safety with careful clinical and pharmacological monitoring. A 7-week double-blind comparison was made of the efficacy and safety of nortriptyline (a tricyclic), phenelzine (a monoamine oxidase inhibitor), and placebo. The results indicated a response rate of approximately 60% for both nortriptyline and phenelzine versus a 13% response rate for placebo. Anticholinergic side effects were more frequently reported in the nortriptyline group. Orthostatic symptoms were reported with similar frequency in both drug groups. Overall, both drugs were well tolerated.

Aged↗

Relationship of platelet MAO activity to characteristics of major depressive illness.

Sixty-seven patients (greater than or equal to 55 years of age) with major depressive disorder had pretreatment assays of platelet monoamine oxidase (MAO) activity. As in previous studies, women had higher MAO activity than men, and MAO activity was positively correlated with age. Patients with melancholia (DSM-III) had significantly higher MAO activity than those without melancholia. This finding may reflect the higher MAO activity associated with the symptoms of anhedonia and mood autonomy. Anxiety also was correlated with higher MAO activity, as was a positive family history of depression. In addition, postdexamethasone cortisol levels were correlated with platelet MAO activity.

Age Factors↗

A variant of the "DIDMOAD" syndrome (diabetes insipidus, diabetes mellitus, optic atrophy and deafness).

A 29-year-old female with diabetes insipidus, deafness, a visual disorder and an abnormal glucose tolerance test, who gave birth to a healthy baby is described. Her male sibling is probably also similarly affected. These patients may represent previously unreported variants of the "DIDMOAD" (Diabetes Insipidus, Diabetes Mellitus, Optic Atrophy and Deafness) syndrome. This is the first reported case of childbirth in an affected patient.

Adult↗

Increased 5-hydroxytryptamine and norepinephrine release from rat brain slices by the Red Sea flatfish toxin pardaxin.

The effect of the Red Sea flatfish toxin pardaxin was examined on K+-evoked and on basal release of either [3H]norepinephrine or [3H]5-hydroxytryptamine from preloaded rat cortical slices. The K+-induced release of the neurotransmitters was stimulated in a dose-related manner at concentrations ranging from 0.5 to 4 micrograms/ml. Basal release of the two transmitters was elevated to a lesser extent. Although the stimulation of evoked release was approximately equivalent for the two neurotransmitters, the response to 5-hydroxytryptamine was reversible whereas that of norepinephrine was not washed by 20 min of superfusion. The mechanisms involved in producing these actions of pardaxin are not known; however, they may be mediated by changes in electrolyte fluxes across the neuronal membranes.

Animals↗

Induction of SOS functions by alkaline intracellular pH in Escherichia coli.

Alkalinization of intracellular pH (pHi) causes an increase in UV resistance in wild-type and pH-sensitive mutant (DZ3) cells of Escherichia coli. Utilizing cells transformed with a plasmid (pA7) which bears the uvrA promoter fused to galK galactokinase structural gene, it was shown that alkaline pHi leads to an increase in the specific activity of galactokinase. This effect was not displayed in a mutant bearing a recA-insensitive lexA gene, nor in cells harboring a plasmid (pA8) in which the galK is fused to a lexA-insensitive uvrA promoter. Hence, the effects of pHi on cells functions may involve the lexA product of the SOS system.

DNA Repair↗

Mental deficiency in pseudohypoparathyroidism type I is associated with Ns-protein deficiency.

Pseudohypoparathyroidism type I is a hereditary disorder characterized by resistance to parathyroid hormone and other hormones that work via cyclic adenosine 3', 5'-monophosphate (cAMP). Most patients with this disorder have generalized deficient activity of Ns-protein (type Ia), which couples stimulatory hormone receptors to catalytic adenylate cyclase. In patients with normal Ns-protein activity (type Ib), a decreased incidence of resistance to hormones other than parathyroid hormone exists. Mental deficiency of unknown cause occurs in 47% to 75% of all patients with pseudohypoparathyroidism type I. Because mutations in the adenylate cyclase-cAMP system may affect the learning ability of Drosophila flies, we assessed mental deficiency in 25 patients whose Ns-protein activity we had determined: 9 of 14 patients with type Ia disorder and 0 of 11 patients with type Ib disorder had mental deficiency. We suggest that Ns-protein deficiency, reduced cAMP levels, or both, are involved in the mental deficiency in these patients and probably in mental function in humans.

Adolescent↗