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Passive muscle stretching is a common physical therapy for critically ill patients in the intensive care units. This study aimed to evaluate the effects of unilateral passive stretching of the gastrocnemius muscle (GM) before and after surgery on blood volume (BV) in the contralateral (non-stretched) GM in patients who are sedated after surgery.We enrolled eight patients with esophageal cancer. The patients completed two sessions of passive cyclical stretching (20-s hold, 10-s release, 10 cycles) of the right GM: one before surgery (awake) and one after (under sedation). We used near-infrared spectroscopy to measure the BV in the stretched and contralateral GM. BV kinetics were compared between the ipsilateral and contralateral GM.In seven of the eight patients, BV in the stretched GM decreased during stretching and increased during the stretch-relaxation phase, both before and after surgery. Both before and after surgery, the change in the BV in the contralateral GM was inversely synchronized to the stretching cycle.Unilateral passive stretching of the GM influenced the microcirculation of the contralateral GM. The mechanism underlying the synchronous change in the BV in the contralateral GM remains to be clarified.

The aim of the present paper is to analyze the results of a self-assessment questionnaire meant to classify students attending ICT classes using clustering methods. The questionnaire survey consisted of 25 educational skills and was conducted in Tokai University using a computer-assisted web-interviewing technique both before and after participants attended ICT classes. The questionnaire results were analyzed using an agglomerative hierarchical clustering based on Ward’s method and a self-organizing map. The findings of the present paper show that students attending ICT classes could be classified into several groups based on the classes they attended and their respective academic faculties.

Liposome-encapsulated hemoglobin (LEH) was proven to be protective in cerebral ischemia/reperfusion injury. The present study evaluated LEH in a rat model of permanent middle cerebral artery (MCA) occlusion to clarify its effect during ischemia and reperfusion. Five minutes after thread occlusion of the MCA, rats were infused with 10 mL/kg of LEH (LEH, n = 13), and compared with normal controls (n = 11). Additional animals received the same MCA occlusion with no treatment (CT, n = 11), saline (saline, n = 10), empty liposome solution (EL, n = 13), or washed red blood cells (RBC, n = 7). Severity of brain edema was determined 24 h later by signal strength in T2-weighted magnetic resonance imaging of the cortex, striatum, hippocampus, and pyriform lobe. The results showed that brain edema/infarction observed in any vehicle-infused control was significantly more severe than in LEH-treated rats. There was a tendency toward aggravated edema in rats receiving ELs. LEH infusion at a dose of 10 mL/kg significantly reduced edema formation as compared to other treatments in a wide area of the brain 24 h after permanent occlusion of the MCA. Low oncotic pressure of EL and LEH solution (vehicle solution) appeared to cause nonsignificant aggravation of edema and reduced protective effects of LEH.

Exercise capacity is frequently decreased in patients with chronic obstructive pulmonary disease (COPD), and muscle dysfunction is one factor in this reduction. Studies using (31)-phosphorus magnetic resonance spectroscopy ((31)P-MRS) have shown that phosphocreatine (PCr) and muscle pH (pHi) are significantly decreased in patients with COPD during mild exercise, suggesting the early activation of anaerobic glycolysis in their muscles. Thus, muscle oxygenation states during exercise might differ between patients with COPD and healthy individuals. We simultaneously measured oxygenation state and pHi in the muscles of patients with COPD during the transition from rest to exercise (on-transition) using near infrared spectroscopy (NIRS) and (31)P-MRS. Sixteen patients with COPD (aged 68.6 +/- 7.5 years) and 7 healthy males (controls; aged 63.3 +/- 7.5 years) performed dynamic handgrip exercise (lifting a weight by gripping at a rate of 20 grips per min for 3 min). Patients were classified based on pHi data at the completion of exercise as having a normal (>or= 6.9; n = 8) or a low (< 6.9; n = 8) pHi. The deoxygenated hemoglobin/myoglobin (deoxy-Hb/Mb) in NIRS recordings remained constant or slightly decreased initially (time delay), then increased to reach a plateau. We calculated the time delay and the time constant of deoxy-Hb/Mb kinetics during the on-transition. The time delay was shorter in the group with a low pHi than in the controls. These findings might reflect a slower increase in O(2) delivery in patients with a low pHi, which might partly account for altered muscle energy metabolism.

Background: The 6-min walk test (6MWT) has been used to assess functional exercise performance in patients with COPD. Although hypoxemia has been occasionally accompanied with the 6MWT in patients with COPD, the oxygenation state of the lower limb muscles during the test has not been investigated. Aims: To determine the oxygenation state of the calf muscle during the 6MWT in patients with COPD and healthy elderly subjects using a mobile near infrared spectroscopy (NIRS) device. Methods: Seven male patients with COPD (COPD group: age, 71.4 ± 2.8 years) and 6 healthy elderly men (H group: age, 69.2 ± 4.1 years) performed the 6MWT. Changes in oxygenated hemoglobin (oxy-Hb), deoxygenated hemoglobin (deoxy-Hb), and total hemoglobin (t-Hb) in the right gastrocnemius muscles (MG) during the 6MWT were measured by NIRS. In addition, SpO2 and pulse rate were monitored by a pulse oximeter. Δt-Hb and Δoxy-Hb were calculated from the difference between the lowest value at the early phase of walking and the value at the cessation of the 6MWT. Exercise intensity was estimated by the Karvonen formula. Results: The lowest value of SpO2 during the 6MWT was 84.6 ± 9.2% in the COPD group. Walking distance was not significantly different between the COPD (492.3 ± 56.5 m) and the H group (578.0 ± 42.9 m). The COPD group showed low Δoxy-Hb values despite a low exercise intensity. The oxy-Hb value decreased along with SpO2 in two patients with COPD. Conclusion: The oxygenation state of MG during the 6MWT in patients with COPD may be different from that in healthy elderly men. The blood oxygen saturation may influence the oxygenation of MG during the 6MWT.

Simultaneous measurements of muscle energy metabolism using (31)P-magnetic resonance spectroscopy ((31)P-MRS) and the kinetics of muscular oxygen metabolism using near-infrared spectroscopy (NIRS) were conducted in polymyositis (PM) patients. The subjects were 12 PM patients (age 45 +/- 12 years) and 12 normal controls (age 41 +/- 12 years). The muscle phosphocreatine (PCr) index and intracellular pH (pHi) were determined with (31)P-MRS and the changes in intramuscular oxygenated (oxy-Hb), deoxygenated (deoxy-Hb), and total haemoglobin (total Hb) were evaluated with NIRS . The pHi and PCr index before steroid therapy in PM patients were significantly lower during exercise than in normal controls, and their recovery was statistically significantly delayed compared with the controls. The pattern of changes in NIRS over time before steroid therapy in PM patients differed from that in normal controls. There were smaller changes in deoxy-Hb and oxy-Hb during exercise, and total Hb decreased during exercise. In contrast, the kinetics of muscular metabolism after steroid therapy showed changes similar to those seen in normal controls. Simultaneous (31)P-MRS and NIRS measurements to determine the kinetics of muscular metabolism are expected to be useful as a noninvasive approach for the evaluation of treatment effects in PM patients.

Long-term bilateral common carotid occlusion (BCCAO) in rats induces brain hypoperfusion and structural injury, and could have relevance as a model of vascular dementia in which cortical metabolism is reduced. The present study was designed to assess whether phosphate-related energy compounds and blood supplies are markedly affected by KCI-induced cortical spreading depression (CSD), which leads to metabolic and cerebral blood flow changes in rats with chronic BCCAO, by means of near-infrared spectroscopy and phosphorus magnetic resonance spectroscopy. Male Wistar rats were divided into 4 groups: BCCAO for 1 week (n = 6) and 4 weeks (n = 15), and sham operation for 1 week (n = 7) and 4 weeks (n = 7). The phosphocreatine (Pcr) index (PCr/PCr+Pi) and intracellular pH (pHi) were measured pre-CSD, just after KCl application, and at 20 and 40 minutes after CSD. Brains were evaluated by histology with hematoxylin and eosin and immunohistochemical reaction for glial fibrillary acidic protein (GFAP). Rapid signal changes of oxy-, deoxy-, and total hemoglobin were observed in all KCl-applied brains. The PCr index and pHi values in BCCAO were not different than those in control rats. The percentage of vacuolated area in the optic tract and percentage values of GFAP-positive area in the frontoparietal cortex were significantly increased in BCCAO. The generation of CSD was seen in regions of cortical gliosis induced by BCCAO, and severe energy exhaustion did not occur during or after CSD. Our results may suggest that the functional interaction of neurons and glia is sustained even in brain tissue where the metabolic state of neurons is impaired and astrocytes are proliferated.

KUTSUZAWA, T., S. SHIOYA, D. KURITA, M. HAIDA, and H. YAMABAYASHI. Effects of age on muscle energy metabolism and oxygenation in the forearm muscles. Med. Sci. Sports Exerc., Vol. 33, No. 6, 2001, pp. 901–906. Purpose: The effects of aging on muscle metabolism and oxygenation have not yet been elucidated. We evaluated the effects of aging on energy metabolism and oxygenation in sedentary healthy subjects by simultaneously measuring 31P-magnetic resonance spectroscopy (MRS) and near-infrared spectroscopy (NIRS). Nine young (28.1 ± 5.0 yr) and nine older (61.4 ± 4.6 yr) healthy subjects were studied. The 31P-MR spectrum was obtained every 15 s during and after hand gripping exercise. Intracellular pH (pHi) and PCr/(PCr+Pi) [PCr: phosphocreatine, Pi: inorganic phosphate] were calculated as an index of energy metabolism. The time constant of the PCr/(PCr+Pi) recovery (τ PCr) was calculated. With NIRS, we evaluated the recovery rates of oxygenated (RHbO2) and deoxygenated hemoglobin (RHb) during the initial 10 s of recovery. The PCr/(PCr+Pi) and pHi at rest and at completion of the exercise and τ PCr did not differ between young and older subjects. However, RHbO2 and RHb were significantly slower in older subjects than in young subjects. The results suggest that muscle energy metabolism in the forearm muscle was not affected by aging. The slower RHbO2 and RHb in older subjects suggested impaired O2 supply, which was probably due to impaired peripheral circulation caused by the process of aging.

The free water content of lung tissue was investigated by dielectric spectroscopy in normal lungs and in pulmonary edema induced by oleic acid in rats. The dielectric relaxation in a frequency range of 107 to 1010 Hz was measured with the time domain reflectometry method at 25°C. Three dielectric relaxation processes were analyzed for the lung tissue. A high-frequency process around 10 GHz was attributed to the orientation of free water molecules based on the relaxation time [log τh (in s) = −11.03]. The dielectric strength (Δε) of this high-frequency peak (Δεh) should reflect the amount of free water in the tissue. Because the measured Δεh depended on the air content of the lung samples, the value of Δεh was corrected for the air content of each sample as determined by the point-counting method in the area where the time domain reflectometry data were obtained. The lungs of rats that received an injection of oleic acid had a significantly increased free water content [(Δεh of lung/Δε of pure water) × density of pure water] compared with that in the normal lung (0.76 vs. 0.59 g/cm3). These results indicate that free water occupies ∼60% of the total volume of normal lung tissue and that there is an increase in free water in pulmonary edema.

Nuclear magnetic resonance transverse relaxation time (T2) was previously measured in studies of lung water. The T2 decay curves for peripheral lung tissue were found to be multiexponential with two T2 components: T2 fast (T2f) and T2 slow (T2s). This behavior was explained by the compartmentalization of water, in which the protons of water are restricted and do not undergo rapid exchange between the compartments. We investigated the origin of the water for these T2 components using excised rat lungs. The effect of magnetic field inhomogeneity due to air-tissue interfaces was examined by degassing some lungs. The contribution of intravascular water was examined by perfusing the lungs with oil or NaCl solutions. Degassing produced a greater increase in the T2f than the T2s component, indicating that the water in the alveolar walls exposed to air spaces contributed to the T2f. Perfusion with oil decreased the T2s, indicating that intravascular water contributed to the T2s component. The effects of intravascular osmotic pressure on the T2f and T2s components suggest that intracellular water is related to the T2f component.

各種抗浮腫薬の虚血性脳浮腫に対する影響をMRIを用いた画像解析により検討した.SDラット26匹に頸動脈カテーテル法により右中大脳動脈閉塞を作製し, 24時間後0.5テスラのMRIを用いて軸状断T2画像を厚さ3mmの間隔で撮影した.撮影後直ちにglycerol 1.7g/kg (n=9), manllitol 3.3/kg (n=9), furosemide 17mg/kg (n=8) のうちいずれかを腹腔内に投与し, 2時間後にMRIを再撮影した.全脳高信号領域容積はglycerol, mannitol, furosemide投与前後でそれぞれ207→191mm3, 189→177mm3, 189→180mm3と減少し, 変化率は92% (p

脱血による血圧下降時の脳内各部位の脳循環自動調節能を, サルにおいてstable Xe-CT法を用いて比較検討した.対象は日本ザル10匹である.血圧下降前後における脳内各部位の脳血流 (CBF) を測定した.血圧下降前における各部位の脳血流は, 大脳基底核部90.8±41.2, 大脳皮質96.8±35.1, 大脳白質56.6±21.1, 小脳半球50.0±19.3ml/100g brain/min (mean±SD) であった.脱血による血圧下降時の脳血流の維持状態を, 脳内各部位の平均自動調節能指数 (MAI), すなわち正常血圧時 [平均動脈血圧 (MABP) 90mmHgから130mmHg] におけるCBFの平均値からMABP50mmHgにおけるCBFを減じた値を, 更に正常血圧時におけるCBFの平均値で除したもので表現した.その結果, 脳内各部位において, 脳循環自動調節能には, 有意な差は認められなかった.

We investigated the relationship between nutritional status and muscle energy metabolism during exercise in 18 male patients with chronic obstructive pulmonary disease (COPD) and 15 male control subjects using 31P nuclear magnetic resonance spectroscopy (31P-MRS). The patients and control subjects were further categorized as in either a well-nourished (% ideal body weight, % IBWor = 90) or malnourished (% IBW90) state. Muscle energy metabolism was evaluated by determining the ratios PCr/(PCr + Pi) (PCr, phosphocreatine; Pi, inorganic phosphate), and ATP/(PCr + Pi + ATP). The exercise consisted of repetitive hand grips performed against a load. The work rate was normalized for the individual's lean muscle mass by dividing work performed by the forearm fat-free cross-sectional area, which was calculated using 1H-MRS. The PCr/(PCr + Pi) values during exercise did not correlate with the % IBW in any of the groups of control subjects or COPD patients. Furthermore, the PCr/(PCr + Pi) did not correlate with the normalized work rate in either the well-nourished or malnourished subject groups. However, there were correlations within the groups of control subjects and COPD patients. The PCr/(PCr + Pi) values for the normalized work rate were consistently lower in the COPD patients than in the control subjects. These findings suggest that the altered muscle metabolism in COPD patients is not affected by their nutritional status.

The use of 31P-magnetic resonance (MR) spectroscopy (31P-MRS) allows noninvasive measurement of high-energy phosphate compounds such as phosphocreatine (PCr) and adenosine triphosphate (ATP), and the low-energy breakdown product, inorganic phosphate (Pi), in exercising muscle. Ratios of measureable highand low-energy phosphate metabolites (e.g., PCr/Pi or PCr/(PCr+Pi) have been utilized as indices of the overall bioenergetic state of the cell (Sapega et al., 1987). Extracellular Pi does not exist in sufficient quantities to significantly affect 31P-MR spectra (Sapega et al., 1987). Intracellular pH (pHi) can also be measured noninvasively based on the pH-dependent chemical shift of cellular Pi that appears as PCr peaks on 31P-MRS (Sapega et al., 1987; Taylor et al., 1983). A decrease in pHi during exercise suggests lactate accumulation in muscles (Sapega et al., 1987; Taylor et al., 1983).

To evaluate the energy metabolism of peripheral skeletal muscle during exercise in patients with chronic respiratory impairment, the 31P-nuclear magnetic resonance (NMR) spectra of forearm muscle were investigated in nine patients and nine age-matched control subjects. We calculated the phosphocreatine (PCr) to PCr + inorganic phosphate (PI) ratio, the time constant of PCr recovery and the intracellular pH. The exercise consisted of repetitive hand grips against a 2-kg load every 3 s for 6 min (0.33 W). The patients showed a marked decrease in the PCr/(PCr + PI) ratio and pH in the muscle during exercise in contrast to the control subjects whose PCr/(PCr + PI) showed a minor decrease without any change in pH. The relationship between PCr utilization and pH demonstrated that anaerobic glycolysis switched on earlier in patients with chronic respiratory impairment. A split PI peak was observed in five of nine patients during exercise. The PCr/(PCr + PI) ratio during the last minute of exercise correlated significantly with the vital capacity (% predicted), with the FEV1/FVC, with the body weight, with the maximum strength of hand grip, and with the muscle mass. The results indicate impaired oxidative phosphorylation and the early activation of anaerobic glycolysis in the muscles of patients with chronic respiratory impairment. Several factors related to chronic respiratory impairment, such as disuse, malnutrition and dysoxia, would contribute to the metabolic changes observed in the muscles examined.

Summary Background & aims Although several studies have shown that plasma concentrations of branched-chain amino acids (BCAAs) are reduced in patients with chronic obstructive pulmonary disease (COPD), little is understood about how low concentrations of BCAAs limit exercise in such patients. The present study investigated whether plasma BCAAs are related to energy metabolism in exercising muscle using 31P-magnetic resonance spectroscopy (MRS). Methods We analyzed the plasma amino acid profiles of 23 male patients with COPD (aged 69.2 ± 5.1 years) and of 7 healthy males (aged 64.1 ± 6.0 years). We normalized the exercise intensity of repetitive lifting by adjusting the weight to 7% of the maximal grip power. The intracellular pH and the phosphocreatine (PCr) index (PCr/(PCr + Pi); Pi, inorganic phosphate) were calculated from MR spectra. We evaluated the relationship between intracellular pH and PCr index at the completion of exercise and the plasma BCAA concentration. Results Glutamine concentrations were elevated in patients with COPD compared with healthy individuals. Plasma concentrations of BCAAs correlated with intracellular pH and PCr index at the completion of exercise. Conclusions The findings are consistent with the notion that BCAAs affect muscle energy metabolism during exercise in patients with COPD.

We investigated the effect of alcohol on muscle energy metabolism by using 31P magnetic resonance spectroscopy in 12 chronic alcoholics [6 with neurological signs and symptoms (such as cerebellar ataxia or diplopia) and 6 without neurological signs or symptoms], compared with five healthy subjects who also received acute alcohol loading. Intracellular pH and phosphocreatine (PCr) index [PCr/ (PCr + Pi)] were measured during rest, exercise, and recovery in the left flexor digitorum superficialis muscle. In healthy subjects, acute alcohol loading did not influence the changes of muscle pH and PCr index. Alcoholics with neurological signs showed marked decreases in muscle intracellular pH and PCr index during exercise and a marked delay of pH recovery after exercise. There was no delay of PCr index recovery. Alcoholics without neurological signs showed slight decreases in intracellular pH and PCr index, but rapid recovery of both intracellular pH and PCr index was observed. Marked decrease and delayed recovery in pH, but rapid recovery of PCr index, indicate that the muscle of patients with neurological signs produced lactate during and after exercise to maintain the ATP level, which implies that anaerobic metabolism is favored over aerobic metabolism in these patients.

We evaluated a 63 year-old, right-handed woman by functional MRI (fMRI) in the early and the recovery stages following a cerebral infarction in the right precentral knob. An activated signal in the ipsilateral sensorimotor cortex and contralateral supplementary motor cortex during deteriorated hand grasping (left) was observed in the early stages, whereas being unable to detect in the functionally recovered period. When simultaneous bilateral hand grasping was performed, the activated signal around infarct region was enlarged in recovered period. The functionally neural reorganization processes relating recovered hand movement after localized cortical infarction (precentral knob) was suggested.

We investigated the progression of cytotoxic brain edema induced by 6-aminonicotinamide (6-ANA), a potent antimetabolite of nicotinamide, by measuring the time courses of changes in brain tissue water state (with MRI), histology (with HE NIRS), cerebral blood flow and volume (CBF, CBV), mean arterial blood pressure (MABP), and brain activity (with EEG) up to 10 hours (h). Change in cerebrovascular autoregulation was also investigated. 6-ANA (120 mg/kg) was administered intraperitoneally to 30 male Wistar rats (250–350 g). After 10 h, the T2-weighted signal intensity was increased (p < 0.05), and H&E staining showed severe vacuolation of glial cells. ATP production/consumption and intracellular pH were well maintained up to 10 h, while the intensity of the phosphomonoesters (PME) signal was significantly increased (p < 0.05). Oxygen consumption gradually decreased from 4 to 10 h. CBF and MABP were all significantly increased (by 2.5-fold for CBF) (p < 0.05). Theta and delta wave amplitudes were reduced at 10 h. In summary, 6-ANA (120 mg/kg) induced cytotoxic brain edema from 4 to 10 h. Energy balance and brain activity were well maintained up to 10 h, though cerebrovascular autoregulation was impaired.

The appearance of local cerebral dysfunction at remote regions from the focus in the acute stage of stroke (diaschisis) is well known, but its mechanism has not been established. We have analysed serial MR images of the infarcted brain of rats to evaluate the distribution of oedema. Forty-seven Sprague-Dawley rats were anaesthetized with halothane, and the right middle cerebral artery (MCA) was permanently occluded via the intraluminal approach using a nylon 2-0 suture. At 3, 6, 9 and 24 hours after the occlusion, coronal T(2)-weighted MR images were taken and the signal intensity (SI) was computed at each region of the brain. After occlusion of the right MCA, SI increased diachronically up to 24 hours on the occluded side of the cortex (52.9+/-3.2 to 104.8+/-22.4) and striatum, which are within the perfusion territory of the MCA. SI increment was also observed at the hippocampus, alveus hippocampi and pyriform lobe, which are not within the territory of the MCA, and at some regions of the contralateral side (52.5+/-4.8 to 69.4+/-14.8 at the cortex). These changes were prominent in ischaemia-vulnerable portions, mild in the cortex, and minimal in the striatum. This contralateral side SI increment indicates remote oedema, which corresponds to diaschisis. We suggest that the mechanism of this remote contralateral oedema is the movement of extravasated protein from the lesion.

For better understanding of the behavior of water molecules in the animal brain, changes in magnetic resonance water proton relaxation processes were studied in the rat during maturation. Midbrains of male Wistar rats were removed at various time points ranging from 2 to 70 days after birth. Changes in relaxation time (water proton longitudinal relaxation time by the inversion recovery, and water proton transverse relaxation time by the spin echo and the Carr-Purcell-Meiboom-Gill pulse sequence (CPMG)) and water content were then determined for various stages of brain development. During maturation both water proton longitudinal relaxation time and water proton transverse relaxation time values decreased and this finding paralleled the decline in water content. Using the CPMG pulse sequence, the transverse relaxation time values were observed to separate into two components after 21 days. Morphologically, the most prominent change at the matured stage of midbrain development in the rat is myelination. Water proton relaxation time, which can be estimated using the CPMG pulse sequence, showed a close correlation with myelination in the central nervous system.

Nuclear magnetic resonance (NMR) and time domain reflectometry (TDR) were employed to investigate the bound water of deoxyribonucleic acid (DNA) in aqueous solution. The NMR transverse magnetization of the water protons decays in the manner described by a monoexponential function which gives a single magnetic relaxation time (T 2 ). However, this fact does not mean that the correlation times for rotational reorientation of both bound are free water molecules are identical

The purposes of this study were 1) to identify the nitric oxide (NO) synthase (NOS) isoform responsible for NO-mediated radiation-induced lung injury, 2) to examine the formation of nitrotyrosine, and 3) to see whether nitrotyrosine formation and lung injury are reduced by an inducible NOS (iNOS) inhibitor, aminoguanidine. The left hemithorax of rats was irradiated (20 Gy), and the degree of lung injury, the expression of NOS isoforms, and the formation of nitrotyrosine and superoxide were examined after 2 wk. iNOS mRNA was induced, and endothelial NOS mRNA was markedly increased in the irradiated lung. Nitrotyrosine was detected biochemically and immunohistochemically. Aminoguanidine prevented acute lung injury as indicated by decreased protein concentration and lactate dehydrogenase activity in bronchoalveolar lavage fluid and improved NMR parameters and histology. Furthermore, the formation of nitrotyrosine was significantly reduced in the aminoguanidine group. We conclude that iNOS induction is a major factor in radiation-induced lung injury and that nitrotyrosine formation may participate in the NO-induced pathogenesis.

Models of pulmonary edema have been used to study the nuclear magnetic resonance (NMR) characteristics of lung water. Several investigators have measured changes in the relaxation times in the permeability type of pulmonary edema, but relatively few have measured relaxation times in the hydrostatic type of pulmonary edema. In this study we determined the characteristics of NMR relaxation times T1, T2 (Hahn spin-echo decay) and water content in acute hydrostatic pulmonary edema induced by noradrenaline administration in rats. Changes in T1 and T2 showed a significant prolongation in hydrostatic pulmonary edema. T2 decay curves for peripheral lung tissues were multiexponential and fit two components [T2 fast (T2f) and T2 slow (T2s)]. With two-component T2 analysis, T2s showed greater prolongation than did T2f. The increase in T2s was significantly correlated with an increase in water content, but the increase in the T2f value was not correlated with water content or with a change in T2s. The T2s component, which likely reflected changes in interstitial water, was more closely related than the T2f component to an increase in water content in hydrostatic pulmonary edema. Results suggested that regional changes in hydrostatic pulmonary edema may be evaluated by multicomponent T2 analysis.

The calcium channel activator BAY K-8644, a dihydropyridine (DHP) derivative, has been shown to possess neurochemical and behavioral activities, but its effect on ischemic brain damage has remained unknown. This report describes the effect of the drug on the progression of cytotoxic edema induced by total ischemia of the brain, evaluated by measuring the time constant, k, of elongation of the 1H-NMR relaxation time (T2) after brain biopsy. Twenty–six male Wistar rats were divided into four groups, (a) control (saline) group (n = 10), (b) BAY K-8644 vehicle group (n = 4), (c) BAY K-8644 0.03 mg/kg group (n = 6) and (d) BAY K-8644 0.3 mg/kg group (n = 6). The k value of group (d), 18.2 ± 5.8 min (mean ± SD), was significantly higher compared with those of groups (a) 10.3 ± 1.6, (b) 11.8 ± 1.5 and (c) 9.8 ± 3.3 min (p < 0.01 by ANOVA). These results indicate that BAY K-8644 delayed the progression of cytotoxic edema induced by total ischemia of the rat brain.

The effects of glutamate and the excitatory amino acid antagonist, MK-801, were investigated on the time course of the shift of water from extracellular to intracellular space (progression or cytotoxic oedema) after total brain ischaemia in rats.

In order to clarify the effects of TA-3090 (calcium entry blocker) on the suppression of water after ischaemic events, 16 measurements of T2f were continuously performed on brain biopsy (for 2–60 min) obtained from treated and control Wistar rats. The time constant (k) and NMR parameters (T2f,(○) ∆ T2f, T2fmax(T2f(○) + ∆ T2f) were obtained from 16 values of T2f. The values of k in Wistar rats treated with intravenously administrated TA-3090 (0.5 mg/kg) were significantly prolonged as compared to that of control. There were no significant differences of maximum prolongation of T2f(T2fmax(T2f(○) + ∆ T2f) among three groups. Since the prolongation of T2f after biopsy reflects the water shift from extra to intracellular space, the increments of time constant indicates that TA-3090 suppresses the water shift into intracellular space. Our present results suggest that TA-3090 prevents some processes involved in irreversible cell damage and suppresses the cytotoxic brain oedema in the incomplete ischaemic area where non-competitive calcium channel is inactive.

We sought to determine whether nuclear magnetic resonance relaxation times of water in tissue would be useful to detect molecular damage in lung tissue within 2 weeks after irradiation. Tissue samples were obtained from the lungs of rats at various times between 1 and 14 days after exposure of a hemithorax to 20 Gy60 Co γ irradiation. The spin-lattice relaxation time, T1, was measured by the inversion recovery method, and the spin-spin relaxation time, T2, was measured by both the Hahn spinecho (Hahn T2) and the Carr-Purcell-Meiboom-Gill (CPMG T2) methods. The T2 of lung tissue could be divided into two components, T2 fast ( ${\rm T}_{2{\rm f}}$) and T2 slow ( ${\rm T}_{2{\rm s}}$), which reflected changes in the intracellular and extracellular water, respectively. The CPMG ${\rm T}_{2{\rm f}}$ increased significantly 3 days after irradiation (66.3 ± 2.3 ms compared to 60.8 ± 2.6 ms), and the CPMG ${\rm T}_{2{\rm s}}$ increased significantly 1 day after irradiation (155 ± 11 ms compared to 138 ± 7 ms), pr...