Hajime Yamabayashi

Effects of age on muscle energy metabolism and oxygenation in the forearm muscles

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). METHODS 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 (tau PCr) was calculated. With NIRS, we evaluated the recovery rates of oxygenated (RHbO2) and deoxygenated hemoglobin (RHb) during the initial 10 s of recovery. RESULTS The PCr/(PCr+Pi) and pHi at rest and at completion of the exercise and tau PCr did not differ between young and older subjects. However, RHbO2 and RHb were significantly slower in older subjects than in young subjects. CONCLUSIONS 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.

Magnetic resonance relaxation times in acute hydrostatic pulmonary edema induced by noradrenaline in rats.

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 muldexponential 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.

Role of the Mediastinum as a Part of the Chest Wall: Analyzed by Computed Tomography

Using computed tomography (CT), geometrical changes in pulmonary structures in 4 human volunteers were analyzed. A series of parallel transaxial CT scans of the lung were obtained for each volunteer while he held his breath at maximal inspiration and maximal expiration. Changes in pulmonary structures were evaluated by comparing the maximal inspiration scans for each slice position. The longitudinal displacement of the lung volume was categorized as either a rib cage displacement or a diaphragm-abdominal displacement. The ratio of diaphragm-abdominal contribution to vital capacity was 0.49-0.65 for the volunteers. The thoracic volume displacement was categorized as either a mediastinal displacement or a rib cage displacement. The former was considerably larger than the latter. Since the rostral end of the mediastinum is fixed to the thoracic cage and the caudal end is fixed to the diaphragm, we conclude that the mediastinum-diaphragm boundary converts the axial force generated by the diaphragmatic excursion into radial force.

Cardiac Output and Regional Blood Flow Measurement with Nonradioactive Microspheres by X-Ray Fluorescence Spectrometry in Rats

Since its introduction (Rudolph and Heymann, 1967) a number of studies have employed the radioactive microsphere method to evaluate changes in cardiac output, regional blood flow, and distribution of pulmonary blood flow under various experimental conditions. Unfortunately, the storage, handling, processing and disposing of radioactive materials requires many precautions and restrictions. Recently, an X-ray fluorescence system and the technique of labeling microspheres with stable heavy elements were developed and used to assess the coronary, hepatic and renal blood flow of large animals (Morita et al., 1990; Mori et al., 1992; Sakamoto et al., 1992). However, this method has not been applied to the measurement of blood flow in small animals such as rats. Rats are one of the most commonly used experimental animals, since entire organs can be easily analyzed because of their relatively small size.

Reassembly in vitro of lung surfactant lipoprotein.

Abstract This report describes a successful attempt to reassemble, in vitro , two fractions obtained from bovine lung surfactant lipoprotein. An apoprotein isolated by gel filtration in the presence of sodium deoxycholate was recombined with lipid extracts of the surfactant, in a highly alkaline buffer (pH 10) containing 10 mM sodium deoxycholate. Sonication, dilution 1 to 10, dialysis, and washing by means of centrifugation were used to produce a lipid-protein complex. Centrifugation in a continuous sucrose density gradient revealed that this material had a density of 1.081 gm/ml and a phospholipid/protein ratio respectively almost the same as those of the original lipoprotein.

Isolation of apoprotein from bovine lung surfactant material by sodium deoxycholate.

Aqueous solutions of bovine lung surfactant material were solubilized with a high concentration of sodium deoxycholate and the protein moiety could then be separated from the mixed lipid-sodium deoxycholate micelles by gel filtration in the presence of a micellar concentration of sodium deoxycholate of 10 mM. The lipid-free protein showed only one detectable peak in the gel filtrate and the sedimentation rate of this protein was 12.1 S. Sodium dodecyl sulfate disc gel electrophoresis showed essentially the same pattern as did the protein extracted directly from the bovine lung surfactant material with organic solvents, of which the major component has a molecular weight of 36 000. This protein should be the main apoprotein of lung surfactant material, and the main band in the sodium dodecyl sulfate disc gel electrophoresis, with a molecular weight of 36 000, would constitute the major protein subunit.

Effect of Cold Pressor Test on Carbon Monoxide Diffusing Capacity in Normal Subjects

We investigated changes in the pulmonary carbon monoxide diffusing capacity (DLco) during the cold pressor test (CPT) on 25 normal subjects. In 10 of them we also observed changes in circulatory parameters by a computerized dual cadmium telluride detector system, using an equilibrium radionuclide blood-pool label. DLco and DLco per unit of alveolar volume (DLco/VA) averaged in the control period were 29.4 +/- 4.1 ml/min/mm Hg, 6.1 +/- 0.8 ml/min/mm Hg/l (mean +/- SD). During the 2nd minute of CPT, DLco increased by 3.6 +/- 1.5% and DLco/VA by 5.1 +/- 1.5% (mean +/- SE). The systemic blood pressure increased by 17% (mean increase) whereas the heart rate and the stroke volume remained unchanged. The increases were small but significant (p less than 0.05, p less than 0.01, respectively). We conclude that the increase in DLco is due to cold-induced systemic vasoconstriction followed by a passive shift of blood into the pulmonary vasculature.

Role of alveolar macrophages in development of paraquat-induced lung injury

It is not known if alveolar macrophages (AM) play an important role in the development of interstitial changes in the lung. The purpose of the present study was to learn if AM are related to the initiation of paraquat-induced lung injury in rats. An intraperitoneal injection of 10 mg/kg paraquat was followed by a rapid increase in the number of viable AM. This effect reached a maximum at 24 h after injection. When 90 mg/kg of methylprednisolone was injected subcutaneously at the same time of the administration of paraquat there was no increase in the number of viable AM. After weekly injection of 5 mg/kg paraquat for six weeks, there were histological changes which were significantly supressed by the simultaneous administration of methylprednisolone. Methylprednisolone, however, did not show such suppressive effects when administered 4 d after the injection of paraquat. It is suggested that the emergence of viable AM is one of the key phenomena in the initiation of interstitial changes in paraquat-induced lung injury.

High-dose combination chemotherapy with autologous bone marrow transplantation in lung cancer.

肺小細胞癌3例及び大細胞癌1例に初回治療として, 大量化学療法を自家骨髄移植を併用して施行した. 使用薬剤は小細胞癌がCTX1.49/m2, ApR60mg/m2, ACNU90mg/m2, VCR2mg, 大細胞癌がCTX600mg/m2×2, ADR20mg/m2×2, MTX15mg/m2×2, Procarbazine200mg×10である. 腫瘍縮小効果は全例PRで, 生存期間も標準化学療法と同じであった. 骨髄抑制以外の副作用としては, 発熱を2例に, 問質性肺炎を, 1例に認めた.