PubMed Health⌕ Search

Biomedical subjects

M L Freedman

Publications and source records attributed to M L Freedman.

125 records · Page 7Linked to original sources
PubMed1967

Membranes in polyribosome formation by rabbit reticulocytes.

When rabbit reticulocytes are incubated with n-butanol, an agent disruptive to the structure and function of cellular membranes, there is a rapid disaggregation of the polyribosomes. Reaggregation is promoted when the n-butanol is diluted below a critical concentration or when the cells are washed free of the alcohol and the incubation is continued. Neither disaggregation nor regeneration will occur in the absence of protein synthesis. These observations suggest that integrity of the reticulocyte membrane is necessary for the attachment of ribosomes to messenger RNA and for the formation of polyribosomes.

Adenosine Triphosphate↗
PubMedDate not supplied

Quantitative neuronal c-fos and c-jun expression in Alzheimer's disease.

Apoptosis, or programmed cell death, has been proposed as a mechanism of neuropathology in Alzheimer's disease (AD). Activation of immediate early genes (IEG) c-jun and c-fos appears to be required for the initiation of apoptosis. Furthermore, the expression of c-jun is induced in cultured neurons that undergo beta-amyloid-mediated apoptosis suggesting a direct role for c-jun in the apoptosis of AD neurons. Using immunohistochemical methods, we calculated the average number of neuronal profiles per unit area expressing c-Jun and c-Fos within hippocampal regions CA1, CA2/3, and CA4 in postmortem brain samples from AD patients and age-matched non-AD patients. There was an increase in c-Jun-positive and c-Fos-positive neuronal profile density in nearly all AD hippocampal regions examined. In cerebellum there was no evidence of apoptosis as determined by using TUNEL technique, and negligible c-Jun labeling.

Aged↗
PubMedDate not supplied

Short-term retention of lexical-semantic representations: implications for speech production.

Patients with semantic STM deficits have difficulty comprehending sentences that require the retention of several lexical-semantic representations prior to their integration into higher-level propositions (Martin, 1995: Martin & Romani. 1994). In Experiment 1, patients with a semantic retention deficit had difficulty with the same type of constructions in speech production, namely noun phrases with one or two prenominal adjectives. Their performance improved when they could produce the nouns and adjectives in sentence form, which placed smaller demands on lexical-semantic retention. In Experiment 2 these patients were better able to produce syntactically complex sentences than the prenominal adjective phrases having an equal number of content words, indicating that the findings in Experiment 1 could not be attributed to syntactic complexity. These patients produced more pauses in the sentence constructions in Experiments 1 and 2, suggesting that the timing of such productions is abnormal. In contrast, patient EA, with a phonological retention deficit, performed better than the patients with a semantic retention deficit on the AN phrases despite having a smaller STM span. She showed no significant benefit of producing sentence compared to phrase constructions, and also made fewer and shorter pauses than the other patients. These findings support the multiple capacities view of verbal working memory and suggest that the same semantic retention capacity used in language comprehension is used in speech production.

Aged↗
PubMedDate not supplied

Additive inhibition of in vitro rabbit reticulocyte heme and protein synthesis with combinations of isoniazid, chloramphenicol and ethanol.

Isoniazid, chloramphenicol and ethanol are well known hematopoietic toxins. These agents inhibit in vitro rabbit reticulocyte heme synthesis and, as a result, inhibit protein synthesis. When combinations of isoniazid (2 x 10(-3)M) and ethanol (0.1M), isoniazid and chloramphenicol (10(-3)M) or ethanol and chloramphenicol were present in the same incubation, their inhibitory effects on heme and protein synthesis were additive. These results suggest that the development of clinical hematological toxicity in man may result from additive interaction of chemically unrelated compounds which inhibit the heme synthetic pathway.

Animals↗
PubMedDate not supplied

Anemia and the elderly: is it physiology or pathology?

There is currently a controversy of whether elderly people (over age 65) have an age-related physiologic decline in red cell parameters. If this is so, a new normal range might be established for geriatric patients, as has been suggested by others. However, since anemia is often the first sign of severe illness in a patient, new normal values might include a danger of overlooking patients with true anemia secondary to an underlying disease. In this article we shall review what is known about red cell parameters in elderly patients and attempt to answer the questions of whether new geriatric norms should be established.

Aged↗