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Biomedical subjects

M Spiegel

Publications and source records attributed to M Spiegel.

63 records · Page 4Linked to original sources
PubMed1966

Protein synthesis in micromeres of the sea urchin egg.

A method was developed for isolating large quantities of micromeres from the 16-cell stage of the sea urchin, and measurements were made of their ability to incorporate C(14)-L-valine into protein as compared with that of a mixed suspension of micromeres, mesomeres, and macromeres. Per cell, the rate of incorporation was considerably less for the micromeres than for the suspension of mixed cells. Per unit volume, however, the two types of suspensions showed no significant differences.

Animals↗
PubMedDate not supplied

Quantification of VP22-GFP spread by direct fluorescence in 15 commonly used cell lines.

BACKGROUND: The intercellular transport property of VP22 chimeric proteins offers the opportunity for the improvement of gene therapy delivery systems. Since enhanced therapeutic effects of transduced genes already have been exemplified for chimeric proteins VP22-p53 and VP22-tk, we were interested in examining whether spread of VP22 chimeric proteins is a general biological phenomenon not restricted to distinct tissues or species. METHODS: To study intercellular spread of VP22-GFP fusion proteins, 15 different mammalian cell lines were transfected with 200-2000 ng of VP22-GFP or GFP expression plasmids. Expression of VP22-GFP or GFP was monitored by fluorescence microscopy of live GFP fluorescence and direct FACS analysis. For selected cell lines, antibody detection of VP22-GFP spread was analysed by confocal microscopy as a control. RESULTS: Spread of VP22-GFP fusion proteins was detected in all 15 cell lines tested, and quantified by FACS analysis. Experimental conditions were found to be critical in the investigation of VP22-mediated intercellular spread. CONCLUSION: Results of our study indicate that spread of VP22 chimeric proteins is a general biological phenomenon not restricted to distinct tissues or species. Therefore, further evidence is provided that VP22-enhanced gene therapeutic effects may be obtained irrespective of the target organ/tissue to be addressed.

Animals↗
PubMedDate not supplied

The effects of chronic ethanol treatment on oligomycin sensitive ATPase activity in the guinea pig heart.

In an effort to determine the effect of chronic ethanol ingestion on myocardial oligomycin sensitive ATPase, guinea pigs were fed 15% ethanol instead of drinking water for 34 weeks. Mg2+-ATPase activity of isolated mitochondria was determined in control and alcohol fed guinea pigs at 16, 20, 24 and 34 weeks. To prove a possible higher fragility of the mitochondria from alcohol fed animals, the ATPase activity was also determined in the supernatant after the isolation of mitochondria "100 000 g fraction". Mg2+-ATPase activity of the isolated mitochondria was time dependent reduced to 56% of the value obtained in the control animals. In the "100 000 g fraction" the ATPase activity, however, started to increase after 8 weeks and after 34 weeks it was about twice as high than in the control group. The findings of this study document a decrease in oligomycin sensitive ATPase activity and an increase in mitochondrial fragility after chronic ethanol ingestion. It supports in the thesis that chronic alcohol intake affects the activity of the intrinsic membrane enzymes by structural derangements of mitochondrial membrane. The changes may play a role in the development of alcoholic cardiomyopathy.

Adenosine Triphosphatases↗
PubMedDate not supplied

Menstrual cycle dependent right-to-left shunting: a single-blinded transcranial Doppler sonography study.

BACKGROUND AND PURPOSE: Menstruation has been described as risk factor for neurological decompression sickness in divers. In considering this for paradoxical gas embolism, we hypothesized that there may be a link between cycle-dependent hormonal changes and the manifestation of a right-to-left shunt (RLS). METHODS: 40 women with a regular cycle of 28 days underwent transcranial Doppler sonography examinations (TCD) on day 1 and on day 15 of the menstrual cycle. Cerebral high intensity transient signs (HITS) proved a RLS. RESULTS: We found a 25% RLS incidence consistent with the literature. In 7 of 10 shunt-positive women it was detected mainly or exclusively on day 15. This difference in PFO detection rate is statistically significant (p = 0.031), indicating more RLS during the peri-ovulatory period. CONCLUSIONS: Our results do not support menstruation as a risk factor for neurological decompression sickness. The peri-ovulatory estrogen peak, which leads to systemic vasodilation, may explain our data. Factors that increase the risk for developing a RLS and thereby paradoxical embolism should be avoided, perhaps including diving during the peri-ovulatory period of the menstrual cycle. Furthermore, contrast PFO testing in fertile females may be most sensitive if conducted mid-cycle.

Adolescent↗