PubMed Health⌕ Search

Biomedical subjects

K Ikegaya

Publications and source records attributed to K Ikegaya.

9 recordsLinked to original sources
PubMed1989

[Left ventricular pressure-volume diagram determined by forward and backward formatting of radionuclide ventriculography and analog pressure data].

Pressure-volume (PV) loop is of great value for the assessment of left ventricular (LV) function, but its clinical application has been limited by methodological complexity. A new system was developed to make accurate loop with simplified procedure, and was applied to clinical and interventional study. The system constitutes of a mobile gamma camera, a poly-amplifier and a data processor (GMS-550U, Toshiba Medical) installed in cardiac catheterization labo for simultaneous raw data handling and successive analysis. Since LV time activity curve (TAC) obtained by usual ECG gating is not fully reliable for a entire cardiac cycle, radionuclide data acquired in list mode was formatted forward and backward from ECG trigger together with analog data of LV pressure, ECG and PCG. PV loops were drawn in 10 patients (OMI, AP, MR, HCM) and 5 normals before and after infusion of angiotensin-II (AII), and Emax and LV work (systolic; SW, diastolic; DW, net; NW = SW - DW) were measured. Radionuclide ventriculography was safely performed with cardiac catheterization even in patients with congestive heart failure. Satisfactory PV loops were obtained by the advantage of simultaneous acquisition of RNV and analog data. Changes of ECG, PCG, volume, pressure and derived indices through one cardiac cycle were readily comparable each other. Peak LV pressure (mmHg) increased from 134 to 159 and then 182 by infusion of AII, but no change in heart rate was observed Emax was higher in normals and AP (mean 1.96 mmHg/ml/m2) than in OMI and MR (range of 0.85-1.36). SW increased in response to rise of LV pressure in all subjects. NW increased in normals and AP, but decreased in OMI and MR with relative increase in DW. In conclusion, this new system is feasible for repetitive studies under drug intervention, since it makes accurate PV loop under physiologic state, i.e. without pacing and volume overloading. Variable changes of SW, DW, and NW in response to afterloading were clarified, which may be useful for the evaluation of cardiac reserve in normal and diseased heart.

Angiotensin II↗
PubMed1985

Promoting effect of the new chymotrypsin inhibitor FK-448 on the intestinal absorption of insulin in rats and dogs.

FK-448 is a potent and specific inhibitor of chymotrypsin, which enhances the intestinal absorption of insulin in rats and dogs resulting in a decrease in blood glucose levels in these animals. In dogs, the immunoreactive insulin (IRI) level of plasma rose proportionally to the decrease in blood glucose level. From in-vitro data, insulin was inactivated by pancreatic enzymes or the supernatants of intestine or liver homogenates. FK-448 suppressed the digestion of insulin by pancreatic enzymes and its enhancement of the intestinal absorption of insulin was found to be related to its inhibition of digestive enzymes, especially chymotrypsin.

Animals↗