High-resolution 1H NMR spectroscopy in rat liver using magic angle turning at a 1 Hz spinning rate.

It is demonstrated that a high-resolution (1)H NMR spectrum of excised rat liver can be obtained using the technique of magic angle turning (MAT) at a sample spinning rate of 1 Hz. A variant of the phase-corrected MAT (PHORMAT) pulse sequence that includes a water suppression segment was developed for the investigation. The spectral resolution achieved with PHORMAT approaches that obtained from a standard magic angle spinning (MAS) experiment at a spinning rate of several kHz. With such ultra-slow spinning, tissue and cell damage associated with the standard MAS experiment is minimized or eliminated. The technique is potentially useful for obtaining high-resolution (1)H spectra in live animals.     

Analysis of the impedance spectra of Pt|poly(o-phenylenediamine) electrodes – hydrogen adsorption and the brush model of the polymer films

Electrochemical impedance spectra obtained for poly(o-phenylenediamine) films on platinum in contact with 0.5 M H₂SO₄ solution were analyzed on the basis of the brush model elaborated for conducting polymer films on electrodes. It is assumed that the polymer film consists of short and long polymer chains forming bundles in such a way that only a small part of the metal substrate is covered by the polymeric material. The analysis of the impedance spectra taken at several potentials in the region of hydrogen adsorption on platinum supports the validity of the model. The model has been tested also by varying the film thickness and the roughness of the platinum substrate.     

Multichannel near-infrared spectroscopy in depression and schizophrenia: cognitive brain activation study.

BACKGROUND: Recent developments in near-infrared spectroscopy (NIRS) have enabled the noninvasive clarification of brain functions in psychiatric disorders with measurement of hemoglobin concentrations as cerebral blood volume. METHODS: Ten patients with depression, 13 patients with schizophrenia, and 16 age- and gender-matched healthy control subjects participated in the study after giving consent. The relative concentrations of oxyhemoglobin [oxyHb] were measured with frontal and temporal probes every.1 sec during word fluency and unilateral finger tapping tasks, with two 24-channel NIRS machines. RESULTS: The [oxyHb] increase patterns during the word fluency task varied among the three groups, although their task performances were similar: the depression group was characterized by a smaller [oxyHb] increase during the first half of the task period and the schizophrenic group by a small trough of [oxyHb] at the start of the task period and [oxyHb] re-increase in the posttask period. [OxyHb] increases during the finger-tapping task were rather larger in the patient groups than in the control group. CONCLUSIONS: The characteristic time courses of [oxyHb] changes in the frontal lobe were elucidated for depression and schizophrenia. Near-infrared spectroscopy, with its noninvasiveness and high time resolution, can be a useful tool for research and clinical purposes in psychiatry.     

Impedance Spectroscopy in Human Skin. A Refined Model

Pharmaceutical Research -     

Metabolic and neurological patterns in chronic cerebral infarction: a single-voxel 1H-MR spectroscopy study

The details of brain metabolism in chronic cerebral infarcts have not been clarified. Using proton MR spectroscopy (¹H-MRS) at 1.5 T, we measured biochemical changes in 16 patients with large infarcts involving the motor cortex in the chronic phase (median 293.9 days) and related the findings to clinical data. Localised spectra were obtained using point-resolved spectroscopy, with an echo time of 270 ms. Regions of interest were placed on the frontal lobe, including the precentral gyrus and central sulcus. Motor function was assessed by the manual muscle power test at the time of the ¹H-MRS study. Only three patients with severe paresis had no signal in the lesions and a lactate signal was obtained in 13 cases. N -acetyl aspartate (NAA) was observed in 4 cases with recanalisation of an occluded vessel. Motor function correlated strongly with the NAA/choline-containing compounds (Cho) ratio (P < 0.01) and lactate/Cho ratio (P < 0.01). We found various metabolic patterns, reflecting residual neurological function. Received: 19 August 1996 Addressed: 26 September 1996     

Two-pedal ergometer for in vivo MRS studies of human calf muscles.

This article describes an ergometer that enables human subjects to exercise one or both limbs while (31)P NMR spectra are obtained. Two independent pedals, equipped with position and force transducers, were mounted on the ergometer in order to calculate mechanical work performance. First, the effect of the magnetic field upon the signal coming from the transducers was investigated. Then the ergometer was tested by performing a series of steady-state exercises of increasing intensity. Experimental data showed that actual mechanical power ranged from 1.5 +/- 0.2 W to 11.0 +/- 1.6 W, while the corresponding oxygen consumption increased from 0.28 +/- 0.04 l/min at rest to 0.48 +/- 0.10 l/min at the highest load, and the PCr/(PCr+P(i)) ratio, as calculated from the (31)P spectra, decreased from 0.94 +/- 0.01 at rest to 0.73 +/- 0.04. These results are consistent with the values reported in the literature and show that this ergometer, which is easy to use, is suitable for in vivo spectroscopy research when metabolic steady-state conditions are required.     

人体运动氧代谢的实时无创测定

为探讨运动过程中肌肉组织氧含量的变化规律，用无损近红外光谱学技术（ＮＩＲＳ）对１０名运动员１２ｍｉｎ递增有氧负荷运动的肌氧含量做了实时连续监测，同时测定了血乳酸和心率，相关分析表明，有氧代谢运动肌氧含量下降与血乳酸上升的测定值呈线性相关（ｒ＝－０．９６２）在相同负荷下对运动员和普通受试者的肌氧和血乳酸等参数的实时变化情况做了比较，此外，还检测和探讨了以无氧运动为主的短跑过程中肌氧含量的下降和恢复规     

Evaluation of protective effects of prostaglandin E1 on ischemic liver damage with in vivo 31P-MR spectroscopy

The cytoprotective effect of prostaglandins (PG) was evaluated by in vivo ³¹P MR spectroscopy. Twenty rabbits were divided into two groups; the control group given physiological saline, and the PG group given prostaglandin E₁ (0.5 μg/kg/min). Each solution was infused for 8 min, after which complete hepatic ischemia was induced for 20 min, followed by reperfusion for 40 min. During ischemia, β-ATP decreased to 23.6% and 42.3%, phosphomonoester increased to 260% and 200% of their initial values in the control and the PG groups, respectively. Inorganic phosphate also increased. After reperfusion, β-ATP recovered to 65.2% and 96.5%, phosphomonoester to 130% and 110%, inorganic phosphate to 140% and 120% in the control and PG groups, respectively. The changes during ischemia were significantly smaller and the recoveries during reperfusion were more complete in the PG group. These results may confirm the cytoprotective effect of prostaglandins by in vivo ³¹P-MR spectroscopy.