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M Rispoli

Publications and source records attributed to M Rispoli.

23 records · Page 2Linked to original sources
PubMed1977

Dissociation of lipolysis from the levels of cyclic AMP in rat epididymal fat cells.

Two compounds, theophylline and 8-aza-9-furfuryl-adenine (SQ 4665), were found to maximally stimulate lipolysis in preparations of rat epididymal fat cells in the absence of exogenous hormones. Cyclic AMP levels in lipocytes maximally stimulated by either agent alone were unchanged from control levels. In contrast, lipolysis stimulated by either epinephrine alone or in combination with several cyclic nucleotide phosphodiesterase inhibitors correlated well with increases in the levels of cyclic AMP observed. These results suggest the presence of a non-cyclic AMP dependent pathway for the stimulation of lipolysis in rat epididymal fat cells.

Adenine↗
PubMedDate not supplied

A possible role of chromatin and tightly-bound chromatin proteins on enzyme-catalyzed methylation of DNA.

Upon extensive digestion with DNAaseI of placenta chromatin matrix, previously "stripped" from its loosely-bound components by high-salt extraction, a fraction is obtained that contains almost no endogenous DNA methylase activity but whose DNA, if still included in this whole fraction--not if it has been purified to a protein-free condition--is a good substrate for externally added enzyme. This chromatin matrix can even cause a significant stimulation of methylation of single-stranded Micrococcus luteus DNA by placental methylase. In vivo, this phenomenon may have possible counterparts in the existence of highly-methylated regions of chromatin loops that appear to be protected by tightly-bound protein components from digestion of the "stripped loops" with DNAaseI.

5-Methylcytosine↗
PubMedDate not supplied

Direct coronary vasodilator effects of intracoronary histamine administration in humans.

Histamine is widely present in human tissues and can be released by immunologic and nonimmunologic reactions. Although several direct cardiovascular effects of histamine have been demonstrated in humans, little is known about the direct effects of histamine on the human coronary circulation in vivo. Therefore, we investigated the changes in coronary hemodynamics induced by bolus intracoronary administration of 4 micrograms of histamine to 11 patients with angiographically normal coronary arteries under continuous monitoring of R-R interval from the electrocardiogram, arterial pressure (AP), and coronary sinus blood flow (CBF), measured by thermodilution. Immediately after the end of the intracoronary histamine bolus, with R-R interval and AP unchanged, CBF increased from 144 +/- 20 to 238 +/- 27 ml/min (p less than 0.01) and coronary vascular resistance decreased from 0.7 +/- 0.16 to 0.42 +/- 0.1 mm Hg/ml/min (p less than 0.01). No change in coronary hemodynamics was observed after bolus intracoronary administration of physiologic saline. The effects of histamine on systemic hemodynamics consisted of a transient fall in AP and R-R interval, starting after the onset of changes in coronary hemodynamics. These data show that histamine possesses a direct coronary vasodilator effect in humans, independent of the determinants of myocardial oxygen consumption.

Adult↗