The concentrations and hormonal forms of CCK and VIP have been determined in extracts of the brain and duodenum of the developing and adult pig. In methanol extracts of the brain cortex, the single hormone form, CCK8, increased from 130 +/- 20 (Mean +/- SEM) pmol/g at birth to an adult level of 300 +/- 50 pmol/g. In acid extracts of brain, the predominant immunoreactive form had N-terminal immunoreactivity and increased from 240 +/- 20 pmol/g at birth to an adult level 490 +/- 30 pmol/g; the C-terminal immunoreactivity was about 10-fold lower. The concentrations and hormonal forms of immunoreactive CCK in duodenal extracts did not appear to be age-related. C-terminal immunoreactivity in methanol extracts averaged 140 +/- 20 pmol/g and in acid extracts 240 +/- 60 pmol/g. The concentration of N-terminal immunoreactivity in acid extracts averaged 490 +/- 70 pmol/g. The VIP concentrations in acid extracts of the brain cortex was 13.5 +/- 2 pmol/g at birth and rose gradually to 30 +/- 9 pmol/g in the adult; in duodenal extracts it was 240 +/- 18 pmol/g at birth and 195 +/- 38 pmol/g in the adult. These results are in marked contrast with the ontogeny of these hormones in the rat in which brain concentrations of CCK and VIP in the neonate are less than 10% of adult levels and in which there are age-related changes in the content of these hormones in the duodenum as well.

Aging↗

PubMedDate not supplied

Assessment of T1 time course changes and tissue-blood ratios after Gd-DTPA administration in brain tumors.

Sequential T1 changes in brain tumor tissue after Gd-DTPA administration were investigated in 10 patients, including 4 meningiomas, 2 gliomas, 3 metastatic cerebral tumors and 1 brain abscess. T1 values were measured serially for 60 minutes following Gd-DTPA injection using a magnetic focusing technique. In vitro T1 of the whole blood samples was also comparatively examined. Time processes in the tissue-blood ratio (TBR) were calculated from two-point relaxation rates at 5 and 30 minutes. The obtained ratios of TBR were ranged from 1.0 to 3.0, probably depending on histological types of brain tumor (the value of 1.0 to 1.5 for meningioma and 1.5 to 3.0 for glioma and metastatic tumor). No significant changes in the T1 value were observed in the examined normal tissue and peritumoral edema. These results indicate that Gd-DTPA plays an important role not only as an image enhancer for tumor tissue but also as an indicator for estimating the blood-brain barrier function.

Adult↗

PubMedDate not supplied

Effects of diltiazem and propranolol on irreversibility of ischemic cardiac function and metabolism in the isolated perfused rat heart.

Ischemia was induced by lowering the afterload pressure of the perfused working rat heart, and continued until the heart was reperfused by raising the after load. After ischemia, the following changes were observed: decreases in the pressure-rate product (peak aortic pressure X heart rate) and coronary flow; depletion of adenosine triphosphate and creating phosphate; and accumulation of lactate. When the heart was exposed to ischemia for more than 20 min, reperfusion of the ischemic heart could not restore the pressure-rate product and the tissue adenosine triphosphate completely, suggesting that irreversible ischemic damage occurred. Diltiazem (2.41 X 10(-6), 1.21 X 10(-5), and 2.41 X 10(-5) M) or propranolol (1.69 X 10(-5) and 3.38 X 10(-5) M) was provided for the heart 5 min before the onset of ischemia. In the presence of diltiazem or propranolol, the levels of adenosine triphosphate and creatine phosphate were preserved even after 20 min of ischemia. Reperfusion with the normal perfusate after 20 min of ischemia. Reperfusion with the normal perfusate after 20 min of ischemia with the buffer containing diltiazem or propranolol recovered the pressure-rate product that had been decreased by ischemia, depending on the concentration of diltiazem or propranolol provided. These results indicate that diltiazem, as well as propranolol, delays the onset of irreversible ischemic damage of the heart, suggesting their protective effects on the ischemic myocardium.

Adenosine Triphosphate↗

PubMedDate not supplied

Dichloroacetate attenuates myocardial acidosis and metabolic changes induced by partial occlusion of the coronary artery in dogs.

The present study was undertaken to examine whether dichloroacetate, which inhibits pyruvate dehydrogenase kinase and, therefore, increases the activity of pyruvate dehydrogenase, attenuates myocardial acidosis and metabolic changes induced by coronary occlusion. In dogs anesthetized with pentobarbital, the left anterior descending coronary artery was incompletely occluded to reduce the left anterior descending flow to a half to one third of the original flow (partial occlusion) to produce myocardial (regional) ischemia. Partial occlusion was continued for 90 min, and a bolus injection of saline or dichloroacetate was made intravenously 30 min after the onset of occlusion. Partial occlusion decreased myocardial pH significantly. An injection of dichloroacetate (150 mg/kg) increased myocardial pH that had been lowered by partial occlusion. Myocardial metabolites were measured in other dogs. Partial occlusion decreased the myocardial levels of adenosine triphosphate, creatine phosphate and energy charge potential, and increased that of lactate significantly, without affecting the myocardial levels of pyruvate and nonesterified fatty acids. Dichloroacetate attenuated the ischemia-induced changes in the myocardial levels of adenosine triphosphate, creatine phosphate, energy charge potential and lactate. These results indicate that dichloroacetate attenuates the myocardial acidosis and metabolic changes during coronary partial occlusion.

Acidosis↗

PubMedDate not supplied

Transfer index of MR relaxation enhancer: a quantitative evaluation of MR contrast enhancement.

To clarify the effects of Gd-DTPA on biological water, we examined the effects of the compound on spin-lattice relaxation rate with various concentrations of gelatin solutions. The results indicate that the effects of relaxation rate of Gd-DTPA in biological water fundamentally correspond to those in aqueous solution. To evaluate the distribution of Gd-DTPA in tissues, we introduced a transfer index that represents the product of tissue-blood ratio of Gd-DTPA and the ratio of extracellular volume of a tissue based on the above findings. The index depends neither on dose of the compound nor on Larmor frequency. The clinical significance of the index was studied in patients with brain tumors. The indexes varied from 0.038 to 0.51, depending on the biological characteristics of the tumors. The transfer index may be used in the quantitative evaluation of MR relaxation enhancement, which may be applied to monitoring therapeutic efficacy and to estimating tissue perfusion.

Brain↗

PubMedDate not supplied

The effect of nitroglycerin, dipyridamole, and propranolol on glycogen metabolism during coronary artery ligation in dogs.

Ligation of one of the small branches of the canine left anterior descending coronary artery produced a typical anaerobic response in the region of myocardium that had been perfused by the ligated artery; the myocardial glycogen and phosphocreatine levels decreased, and the myocardial phosphorylase activity increased after coronary artery ligation. Pretreatment of the dogs with nitroglycerin or propranolol prevented or diminished the typical anaerobic response of the myocardium to coronary artery ligation, but the pretreatment with dipyridamole did not.

Adenosine Triphosphate↗