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Biomedical subjects

T Inubushi

Publications and source records attributed to T Inubushi.

At least 91 records · Page 5Linked to original sources
PubMed1993

Brain lithium concentrations measured with lithium-7 magnetic resonance spectroscopy in patients with affective disorders: relationship to erythrocyte and serum concentrations.

Brain lithium concentrations were measured in eight patients with affective disorders using lithium-7 magnetic resonance spectroscopy (MRS). Brain lithium concentrations correlated better with serum concentrations (n = 23, r = 0.66, p < 0.001) than with erythrocyte concentrations (r = 0.44, p < 0.05). Because of previous data in animal experiments these results were unexpected, but the differences in cation transport mechanisms between neurons and erythrocytes may account for the results.

Adult↗
PubMed1993

Energy metabolism of the heart and the liver in brain-dead dogs as assessed by 31P NMR spectroscopy.

The energy metabolism of the heart and the liver was assessed in brain-dead dogs by 31P nuclear magnetic resonance spectroscopy. The mean blood pressure and pulse rate changed respectively from 136.1 +/- 9.3 mm Hg (mean +/- SEM) and 126.7 +/- 4.4/min in the control period, to 212.9 +/- 15.8 mm Hg and 146.7 +/- 13.3/min during Cushing phenomenon (CU period), and to 60.0 +/- 6.4 mm Hg and 60.0 +/- 2.9/min after completion of brain death (BD period). The ratio of creatine phosphate to inorganic phosphate (PCr/Pi) of the heart decreased from 5.00 +/- 1.08 to 3.24 +/- 0.80 in the CU period and increased to the levels of the control values in the early BD period. The intracellular pH of the heart decreased from 7.20 +/- 0.07 to 6.91 +/- 0.02 in the CU period and increased to 7.12 +/- 0.01 in the BD period. The positive relationship between the Pi/PCr and the rate-pressure product (BP x PR) indicates that the regulation of the oxidative metabolism by free ADP was well maintained except at some points in the CU period (Pi/PCr = 8.77 x 10(-6) BP x PR + 0.164, r = 0.704). This suggested that the remarkable hypotension and bradycardia in the BD period is not associated with cardiac energy failure. Although the energy states of both the heart and the liver in brain-dead dogs were adequately maintained in the BD period, the changes were different.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗
PubMed1993

Deuterium chemical shift imaging for the estimation of cerebral perfusion in rabbit infarction model.

In order to develop a new technique for the measurement of local cerebral blood flow (CBF), the deuterium chemical shift imaging (2H-CSI) technique, an application of in vivo nuclear magnetic resonance (NMR), was used for the estimation of cerebral perfusion in rabbit infarction model. The 2H chemical shift images of rabbit brain were obtained every 30 seconds before and after intravenous injection of deuterated saline. The changes in 2H NMR signal intensity documented that the cerebral perfusion in the damaged area due to infarction decreased obviously compared to that in the intact area. These findings indicate that the 2H-CSI technique can be applied to the measurement of local CBF. The readily availability and limited toxicity of deuterated water may make possible to use this method in clinical cases.

Journal Article↗
PubMed1993

Proton magnetic resonance spectroscopy with dementia.

To provide new insights into metabolic changes in the brain of patients with dementia, we performed in vivo localized proton magnetic resonance spectroscopy in nine patients with primary degenerative dementia and in three patients with normal-pressure hydrocephalus. We compared the results with those in 26 healthy volunteers. Measurements of regional cerebral blood flow were performed in seven patients by means of single photon emission computed tomography with amphetamine I 123 as a tracer. The magnetic resonance spectra constantly showed three major peaks corresponding to N-acetylaspartate (NAA), creatine and phosphocreatine (Cr), and choline-containing compounds. There were no age-related changes in the mean area ratio of NAA to Cr in neurologically normal volunteers. The NAA/Cr ratio was significantly reduced in patients with primary degenerative dementia. The reduction of the NAA/Cr ratio was observed even in dementia patients with no significant brain atrophy or reduction in regional cerebral blood flow. No significant reduction of the NAA/Cr ratio was seen in patients with normal-pressure hydrocephalus. The NAA/Cr ratio might reflect the number and/or activity of neuronal cells in the brain. Proton magnetic resonance spectroscopy may well provide a useful tool for early detection of, and further pathophysiological study of, primary degenerative dementia.

Adult↗
PubMed1993

Alterations in brain phosphorous metabolism in bipolar disorder detected by in vivo 31P and 7Li magnetic resonance spectroscopy.

Phosphorus-31 magnetic resonance spectroscopy (MRS), able to detect membrane metabolism and intracellular pH as well as energy metabolism in vivo, was applied to 17 bipolar patients in the manic state and the euthymic state. In nine of these patients, brain lithium concentration was simultaneously determined by means of lithium-7 MRS in order to clarify the effect of treatment with lithium on brain phosphorous metabolism. Both phosphomonoester (PME) peak area and intracellular pH were found to be higher in the manic state than in the euthymic state. These values in the euthymic state were lower than those in normal controls whose ages and sexes were matched with the patients. However, PME and intracellular pH did not correlate to brain lithium concentration. These findings coincide with a hypothesis that patients with bipolar disorder may have membrane abnormality in their euthymic state and state-dependent alteration of catecholaminergic activity may be a secondary phenomenon.

Adult↗
PubMed1993

31P-NMR spectroscopy of isolated perfused rat lung.

We obtained 202.5-MHz 31P-nuclear magnetic resonance (NMR) spectra of isolated perfused rat lungs, degassed and inflated, and of lung extract. The spectra included those of ATP, ADP, phosphocreatine (PCr), inorganic phosphate (Pi), phosphomonoesters, phosphodiesters, and a broad component due to the membrane phospholipids. The line width at one-half peak height for beta-ATP was 1.0 ppm for the degassed lung and 1.2 ppm for the inflated lung. This suggests that the air-water interfaces in inflated lung, which produce proton NMR line broadening, do not act prominently in 31P-NMR spectroscopy. In a degassed lung, when perfusion was stopped for up to 30 min, PCr and ATP peaks decreased progressively with time while Pi and phosphomonoester peaks increased. On return of flow, these changes reversed. The intracellular pH values calculated from the difference in magnetic field between PCr and Pi peaks of inflated and degassed lungs were 7.16 +/- 0.10 (SD; n = 4) and 6.99 +/- 0.10 (n = 4), respectively. The change of intracellular pH caused by 30 min of ischemia was -0.2 pH units. Our findings indicate that air-water interfaces should not broaden lung 31P peaks in vivo.

Adenosine Triphosphate↗
PubMed1993

Hepatic blood flow and energy metabolism during hypotension induced by prostaglandin E1 and nicardipine in rabbits: an in vivo magnetic resonance spectroscopic study.

Hepatic blood flow (HBF) and energy metabolism during moderate hypotension induced by prostaglandin E1 (PGE1) and nicardipine were studied by in vivo magnetic resonance spectroscopy. HBF was determined by the deuterated water clearance method by using deuterium magnetic resonance spectroscopy, and energy metabolism was estimated from the changes in the levels of adenosine triphosphate and inorganic phosphate by using phosphorus (31P) magnetic resonance spectroscopy. Mean arterial blood pressure was intentionally reduced to 60% of control with PGE1 (n = 5) or nicardipine (n = 5). The HBF decreased by 38% and by 50% during the hypotension induced by PGE1 and nicardipine, respectively. The level of adenosine triphosphate decreased by 12% and that of inorganic phosphate increased by 80% during nicardipine-induced hypotension, whereas the corresponding levels showed no remarkable changes during PGE1-induced hypotension. After the cessation of drug administration, mean arterial blood pressure and HBF recovered to the control levels in the PGE1 group, but not completely in the nicardipine group. In the latter group, the level of inorganic phosphate did not recover either. These results indicate that during hypotension induced with PGE1 hepatic circulation and metabolism are conserved to a greater extent than during hypotension induced with nicardipine.

Adenosine Triphosphate↗
PubMed1993

Heterogeneous metabolic changes in the calf muscle of the rat during ischaemia-reperfusion: in vivo analysis by 31P nuclear magnetic resonance chemical shift imaging and 1H magnetic resonance imaging.

Non-localized and localized 31P nuclear magnetic resonance (NMR) spectra of rat calf muscle during arterial occlusion and after reperfusion were concurrently observed using chemical shift imaging and 1H magnetic resonance imaging (MRI). During ischaemia, the levels of high-energy phosphates (phosphocreatine and adenosine 5'-triphosphate) were depleted and that of inorganic phosphate was increased. In addition, the signal intensity on 1H MRI was increased. These changes were observed to be relatively homogeneous throughout the calf. In contrast, the changes during reperfusion were heterogeneous. In the central part of the calf, inorganic phosphate disappeared, phosphocreatine was restored immediately on reperfusion and the 1H signal was decreased. However, in the regions of the tibialis anterior muscle and the superficial part of the gastrocnemius muscle, inorganic phosphate persisted for several hours, phosphocreatine was not restored and the signal intensity on T2-weighted 1H MRI was increased further. The heterogeneous changes detected by 31P NMR spectroscopy and 1H MRI showed close agreement. The susceptibility of different calf muscles to ischaemia and reperfusion seems to depend on their predominant muscle fibre type (i.e. fast-twitch or slow-twitch fibres). Reversible and irreversible ischaemic changes could be non-invasively distinguished by in vivo 31P NMR spectroscopy and 1H MRI.

Adenosine Triphosphate↗
PubMed1992

Chemical assessment of phospholipid and phosphoenergetic metabolites in regenerating rat liver measured by in vivo and in vitro 31P-NMR.

For the assessment of 31P-NMR spectroscopic data, phospholipid precursors (phosphorylethanolamine (PE) and phosphocholine) and catabolites (glycerophosphorylethanolamine (GPE) and glycerophosphorylcholine (GPC)), as well as adenosine phosphates were chemically determined in regenerating rat liver. The data were compared with those obtained by in vivo and in vitro 31P-NMR spectroscopies. Chemical assay revealed a significant increase of PE and a decrease of GPE, GPC and ATP in hepatectomy group compared to sham operation group. The values obtained by in vitro NMR were in good agreements with those of chemical assay, but significant differences between the two groups were observed only in PE and inorganic phosphate (Pi). Noticeable increase in PME was not detected by in vivo 31P-NMR spectroscopy, although the increase of PE was about 2.5-times that of the control and its constitution ratio to the whole phosphomonoester (PME) was less than 15%. On the other hand, in vivo NMR showed a large phosphodiester (PDE) peak occupying approx. 40% of the total phosphorus signal, while the contribution of its constituents, GPE and GPC was about 5% found by both chemical assay and in vitro NMR. The PDE peak in in vivo NMR seemed to reflect the membrane phospholipid itself rather than its catabolites. A slight decrease of phosphoenergetic level in regenerating rat-liver was commonly suggested by all three analytical methods.

Animals↗
PubMed1992

Brain phosphorous metabolism in depressive disorders detected by phosphorus-31 magnetic resonance spectroscopy.

Brain phosphorus metabolism was measured in 22 patients with depressive disorders. Ten of them had DSM-III-R bipolar disorder, and 12 had major depression. In bipolar patients, phosphomonoester (PME) and intracellular pH were significantly increased in the depressive state than in the euthymic state, while those values in the euthymic state were significantly low as compared to age-matched normal controls. Phosphocreatine (PCr) was significantly decreased in severely depressed patients compared to mild depressives. These findings suggest that high energy phosphate metabolism, intracellular pH and membrane phospholipid metabolism are altered in depressive disorders.

Adenosine Triphosphate↗
PubMed1992

Brain lithium concentration by 7Li- and 1H-magnetic resonance spectroscopy in bipolar disorder.

A method was developed to measure lithium concentrations in the human brain using in vivo 7Li- and 1H-magnetic resonance spectroscopy (MRS). Lithium concentrations measured by MRS in 10 lithium-treated bipolar patients were at the half level of those measured in serum. Serial measurements indicated that lithium concentrations in the brain increased markedly during manic episodes, while serum concentrations were unchanged. These findings suggest that in vivo measurements of lithium concentrations in the brain, combined with measurements of concentrations in serum, may be useful in monitoring the effects of therapeutic drugs.

Adult↗
PubMed1992

In vivo 31P nuclear magnetic resonance spectroscopy in patients with old myocardial infarction.

To assess the usefulness of in vivo 31P nuclear magnetic resonance (NMR) spectroscopy, we investigated spectra from the myocardium in 6 patients with old Q-wave infarction (QMI), 6 with old non-Q-wave infarction (NQMI) and 9 controls by ECG-gated depth-resolved surface-coil spectroscopy. External hexamethylphosphoric triamide (HMPT) was used to quantify the signal intensities. Left ventricular weight in the region of interest (LVW) was estimated from 1H magnetic resonance images. The extent score by 201Tl scintigraphy was determined in 3 QMI and 4 NQMI patients. No significant differences were found among the 3 groups in peak area ratios of 31P NMR spectra to phosphocreatine (PCr) or adenosine triphosphate (ATP). Compared with controls, significant reductions were observed in values for the peak areas of PCr normalized by the standard HMPT (PCr/HMPT) or by both HMPT and LVW (PCr/HMPT/LVW) for QMI patients (p less than 0.05), and in ATP/HMPT and ATP/HMPT/LVW for QMI and NQMI patients (p less than 0.01). There was a significant negative correlation between ATP/HMPT and the 201Tl scintigraphy extent score (p less than 0.05). These findings suggest that in vivo 31P NMR spectroscopy can detect high-energy phosphate reduction in the infarcted myocardium and may be useful in evaluating myocardial viability.

Adenosine Triphosphate↗
PubMed1991

In vivo oxygen-17 nuclear magnetic resonance for the estimation of cerebral blood flow and oxygen consumption.

To explore the feasibility of in vivo 17O NMR for the estimation of cerebral blood flow and oxygen consumption, in vivo 17O NMR spectroscopy and imaging were employed in animal models. In the spectroscopy, the changes in the 17O NMR signal intensity after the injection of H2(17)O and the inhalation of 17O2 gas were obtained every 4 seconds with sufficient signal-to-noise ratios for the quantification of cerebral blood flow and oxygen consumption. In the imaging, although the time and spatial resolutions were insufficient for the quantification of H2(17)O, 17O NMR images of rabbit brain could be obtained, indicating that it is possible to map cerebral blood flow and oxygen consumption by 17O NMR imaging.

Animals↗
PubMed1991

[Ca++ antagonist and acute brain ischemia: effects of nilvadipine and nicardipine on middle cerebral artery occlusion in rats].

Effects of calcium antagonists, Nicardipine and Nilvadipine, on neurologic deficits and size of infarct were studied in the rat middle cerebral artery (MCA) occlusion model. Each drug was administered immediately after induction of ischemia, and neurologic grade was evaluated 1 to 24 hours after MCA occlusion. At 24 hours post-occlusion, size of the infarct was compared with that of the control group. In addition, evolution of cerebral infarction was studied at 6 hours and 12 hours post-occlusion by magnetic resonance imaging (MRI). In the Nilvadipine-treated group, neurologic deficits improved more rapidly and the size of infarct was significantly smaller than in the Nicardipine-treated group. MRI showed a progressive extension of cortical infarct in the untreated rat, whereas the infarct size remained unchanged in the Nilvadipine-treated rat. These results suggest the potential therapeutic usefulness of calcium antagonist for acute cerebral ischemia.

Acute Disease↗
PubMed1991

Energy metabolism of the liver in brain dead dogs assessed by 31P-NMR spectroscopy and arterial ketone body ratio.

The changes in hepatic energy state were assessed by 31P-nuclear magnetic resonance spectroscopy (31P-MRS) and arterial ketone body ratio (AKBR) in brain dead dogs. 31P-MRS and AKBR were measured before and at 3 hours after brain death. Wiggers' shock model was employed to compare the energy metabolism during hypotension. 1) The brain death model: Systemic blood pressure changed from 178.3/115.0 mmHg (mean) in the control period, to 259.5/162.5 mmHg during Cushing phenomenon (CU period) and to 63.3/51.7 mmHg after completion of brain death (BD period). beta-ATP/Pi increased from 1.27 +/- 0.14 (mean +/- SEM) to 1.46 +/- 0.16 in the early CU period, and then decreased to 1.11 +/- 0.15 at 60 minutes after BD, followed by a gradual increase to 1.33 +/- 0.13 at 3 hours after BD. Intracellular pH (pHi) increased alkaline to the control value. AKBR decreased from 1.10 +/- 0.26 to 0.46 +/- 0.15 in the CU period (p less than 0.05) and then increased to 1.48 +/- 0.25 after BD. 2) Wiggers' shock model: Systemic blood pressure was 190.0/112.5 mmHg in the control period, 83.8/51.3 mmHg during exsanguination (EX period) and 185.0/117.0 mmHg after retransfusion (RT period). beta-ATP/Pi decreased from 1.17 +/- 0.13 to 0.61 +/- 0.10 in the EX period (p less than 0.05) and increased to 1.37 +/- 0.08 in the RT period. The pHi deviated from 7.33 +/- 0.07 to 6.82 +/- 0.14 in the EX period (p less than 0.01) and to 7.51 +/- 0.21 in the RT period. AKBR decreased from 1.00 +/- 0.11 to 0.21 +/- 0.04 in the EX period and increased to 1.08 +/- 0.12 in the RT period. The energy metabolism of the liver was well maintained in the state of brain death in spite of remarkable hypotension, although that was not the case with Wiggers' shock model. It was suggested that the combination of 31P-MRS and AKBR was useful for the evaluation of graft liver viability.

Adenosine Triphosphate↗
PubMed1991

Measurement of brain phosphoinositide metabolism in bipolar patients using in vivo 31P-MRS.

In vivo phosphorus-31 magnetic resonance spectroscopy (31P-MRS) was used to measure phosphorus metabolism in the brains of manic patients treated with lithium carbonate. The phosphomonoester (PME) peak was elevated in the manic state in patients with DSM-IIIR bipolar disorder compared to the euthymic state and to drug-free normal controls. Elevation of the PME peak may be caused by lithium-induced accumulation of inositol 1-phosphate in the brain.

Adult↗