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Biomedical subjects

M Moskowitz

Publications and source records attributed to M Moskowitz.

At least 109 records · Page 6Linked to original sources

Difference in transport of leucine in attached and suspended 3T3 cells.

3T3 cells in subconfluent culture take up leucine through a transport system which has a relatively high affinity for leucine (M system). When the culture becomes confluent, the M system is turned off and leucine is transported by another system which has a low affinity for leucine (S system). The M system is reactivated by transferring the cells into subconfluent cultures. In suspension cultures 3T3 cells, initiated from confluent cultures, the M system is not activated and leucine is transported by the S system. In cells suspended from subconfluent culture, the M system continues to operate at a high level for four hours and then is gradually turned off. Tumor virus transformed 3T3 cells (SV3T3 and Py3T3) grow quite well in suspension culture and transport leucine both in monolayer and suspension through a high affinity system, with a high Vmax value. A derivative of 3T3, 3T3/41, which grows in suspension much more slowly than tumor virus transformed 3T3 cells, also takes up leucine through a high affinity transport system both in monolayer and suspension but its Vmax value is lower than that of the transformed cells.

Animals

Anchorage dependent changes in transport of glucose, adenosine, uridine and leucine in 3T3 cells.

There is a low uptake of leucine in suspension cultures of 3T3 cells relative to the uptake in sparse monolayer cultures. The pattern of uptake of deoxyglucose is similar in suspension and monolayer cultures and changing the medium or adding serum stimulates uptake under both culture conditions. The uptake of uridine and adenosine is greater in suspension culture than in monolayer culture. Cells do not multiply in suspension culture but do multiply in monolayer culture and thus there is a correlation between uptake of leucine and conditions which stimulate cell multiplication, but not correlation of the uptake of deoxyglucose, uridine and adenosine with these conditions.

Adenosine

Arrest of 3T3 cells in G1 phase in suspension culture.

3T3 cells do not grow in Methocel suspension culture, while other permanent cell lines do. The viability of 3T3 cells in suspension remains unchanged for at least three days with respect to plating efficiency, vital staining and resumption of normal growth when transferred into monolayer culture. When monolayer 3T3 cells in G1 phase are suspended they remain in G1 phase. Cells already in S phase which are suspended complete ongoing DNA synthesis and mitosis and then are arrested in the G1 phase. Progress through the cell cycle is reinitiated after suspended cells attach to a surface. When monolayer cells in late G1 phase (just before entering S phase) are put in suspension cultures they do not initiate DNA synthesis.

Cell Division

Rotational behavior in gerbils following unilateral common carotid artery ligation.

Unilateral cerebral infarctions are produced in 30-50% of all gerbils subjected to ipsilateral ligation of a common carotid artery. It has previously been shown that this infarction is associated with a major depletion if ipsilateral brain dopamine. The present studies characterize the spontaneous and drug-induced rotational behavior manifested by these animals and attempt to relate it to the functional activity of dopaminergic synapses. The tendency of animals to turn towards the side of the lesion 2-3 hours after surgery was found to correlate highly with the unilateral dopamine depletion observed after 24 hours. Two patterns of rotational responses were observed among animals showing symptoms that were treated with d-amphetamine or apomorphine; these could be correlated with mortality 24 hours after surgery.

Amphetamine

Evaluation of mammographic calcifications using a computer program.

A computer pattern recognition program was developed to evaluate calcifications seen on mammograms. When the approximate horizontal length, average internal gray level, and contrast were used as criteria, 84.3% of the lesions studied were correctly identified as malignant or benign. These results show that a computer program can help evaluate calcifications of the breast.

Breast Neoplasms

The psoas sign, hepatic angle, normal patients, and everyday practice.

While extensive previous references in the literature leave little doubt that disease in the posterior pararenal space can obliterate the psoas margin either in its entirety or in part, little work has been done to evaluate the frequency of when the psoas cannot be visualized in normal individuals. The data presented here indicate that as the right psoas can be expected to be absent in normal patients from 16 to 43% of the time, therefore one cannot ;lean' heavily on it as a clinical tool. On the other hand, absence of the left psoas margin on a single film in the proper clinical setting may be sufficient to draw one's attention to the retroperitoneal space, more particularly the posterior pararenal space, as a possible site of abnormality. However, ancillary radiographic signs such as mass displacement, gas, calcium, or abnormal depositions of fat, should be carefully sought. Preservation of either or both psoas margins certainly does not exclude by any means significant extraperitoneal disease, as can be seen even in our small anecdotal series. The hepatic angle is absent with such frequency in normal patients that it too can only be of questionable value as a primary radiographic sign. In our normal group of patients the splenic angle was absent more frequently than it was present.

Adolescent