Brain abscess observed by localized proton magnetic resonance spectroscopy

We encountered a case of brain abscess that was difficult to differentiate from glioblastoma. Localized ¹H-MRS was found to be useful for obtaining information on the biochemical status of brain abscess. The peak of lipid and high residual peak of NAA (N-acetyl-aspartate) were observed in the cystic lesion of the brain abscess by ¹H-MRS. The NAA/Cho (Choline-containing compounds) ratio in brain parenchyma showing an edematous lesion before therapy gradually increased with the relief of inflammation.     

Critical brain networks

Highly correlated brain dynamics produces synchronized states with no behavioral value, while weakly correlated dynamics prevents information flow. We discuss the idea put forward by Per Bak that the working brain stays at an intermediate (critical) regime characterized by power-law correlations.     

Anoxia followed by hyperoxia: In vivo 31-P NMR of cat brain

In vivo ³¹P NMR spectroscopy was performed on a cat brain subjected to an extended period of anoxia followed by restoration of oxygen. High energy phosphate spectra were continuously obtained and pH measured. Following the onset of anoxia, phosphocreatine and ATP peaks decreased with a concomitant increase in inorganic phosphate. Following 34 min ventilation on 100% N₂, the animal was ventilated on 100% O₂. The spectral content progressively changed, inorganic phosphate decreased and ATP increased with the spectrum closely resembling that of control. Our results suggest that the absence of NMR detectable ATP signal cannot be interpreted as an irreversable change in cellular metabolic function.     

原子吸收光谱法测定小白鼠脑组织中Na,K,Ca

本文利用空气－煤气火焰或空气－乙炔火焰原子吸收光谱法分别测定小白鼠脑组织中Na,K,Ca。样品用HNO3－KClO4体系消化。用LaCl3消除P对Ca的干扰，以CsCl作Na,K的消电离剂。共测定了4组46个不同代表性的样品，测定Na,K,Ca的相对标准偏差（RSD）分别为0.886%,0.691％和0.824%，加标回收率分别为100.6%,102.0%和98.4%。     

In vivo sodium-23 magnetic resonance surface coil imaging: Observing experimental cerebral ischemia in the rat

Sodium-23 magnetic resonance imaging can be used to detect and assess experimental cerebral ischemia in the rat. An imaging technique utilizing a surface coil is described to produce sodium magnetic resonance images of good quality and resolution within 10 min. A novel method of hemispheric occlusion showed edema in the right brain of the rat head within 3 hr after injury. The edema was especially pronounced by 12 hr with effects in the right brain, eye and surrounding muscle evident.     

脑血管病患者血清锌,铜,铁,钙含量与病情的关系

测定了４２例脑血管病患者血锌、铜、铁、钙含量，结果显示急性期患者血锌含量明显低于正常值，且病情越重，血锌下降越明显。临床上测定脑血管病患者血锌含量对评估患者病情、判断预后有一定意义。     

Cyclopentadienyl tricarbonyl complexes of Tc for the in vivo imaging of the serotonin 5-HT1A receptor in the brain

Technetium and rhenium tricarbonyl complexes with derivatized cyclopentadienyl ligands were prepared starting from pertechnetate and an appropriate ferrocene ligand. Furthermore, the complexes (M(CO)₃cp-COOC₅H₉N-R, M = Tc, Re; R = Me, isopropyl) could be obtained starting from the precursor complexes [^99mTc(CO)₃(H₂O)₃]⁺ and [Re(CO)₃Br₃]²⁻. Their chemical identity was confirmed by chromatographic methods and electron spray mass spectrometry. The biodistribution of the ^99mTc complexes (cytectrene I and cytectrene II) in Wistar rats was studied. Both compounds show high uptake in the brain and fast blood clearance. The pattern of regional distribution in the brain demonstrated in autoradiographic studies indicates binding to the 5-HT_1A and α₁ adrenergic receptors.     

Recent Advances in Analytical Methodology for in vivo Electrochemistry in Mammals

Electrochemistry is one of the most advanced techniques for monitoring neurochemical activities in the living brain because electrochemical approaches bear the advantageous features of high spatial and temporal resolutions, which facilitate its tremendous potential in investigating the highly spatially heterogeneous brain system and the fast dynamics of neurochemical activities. On the other hand, since brain is the most complicated organ in the sense of its numerous kinds of neurochemical species, high selectivity is always required for any analytical methods that approach the brain. In this review, we will discuss various electrochemical methodologies to achieve selective detection of neurochemicals in mammalian brain and the strategies developed mainly by our group towards selective monitoring of both electrochemically active and inactive neurochemicals. At the end, we will discuss possible solutions towards brain mapping of neurochemical species and combination of neurochemical detection strategy with electrophysiology as the direction of future development of electroanalysis in living brain.     

Multiparametric analysis of amino acids and organic acids in rat brain tissues using GC/MS

Using design of experiment (DOE) theory coupled with multivariate statistical analysis, we have developed a simple and reliable GC/MS-based analytical assay for simultaneous analysis of amino acids and organic acids in rat brain tissue samples. The process of water extraction (pH 10.0) was extensively evaluated using brain tissue samples and a set of 21 reference standards. Acceptable calibration curves were obtained over a wide concentration range, 0.2-35.0 microg/mL for standards and 15.0-2.4 mL/g (tissue) for brain tissue samples. The precision was mostly better than 10% for both the mixed standards and the brain tissue samples. The brain tissue samples exhibited good stability within 48 h with RSD generally less than 15%. Furthermore, the developed analytical method was successfully applied in distinguishing the subtle variation among different parts of the brain tissues, such as cerebral cortex, hippocampus, and thalamus.     

Experimental development of a petal resonator surface coil

A surface coil for MRI was designed and built based on the principles of the petal resonator proposed by Mansfield [J Phys D Appl Phys 21 (1988) 1643]. This resonator coil design was named the petal resonator surface (PERES) coil and is composed of an eight-petal coil array and a central circular coil. A minimum separation of three times the petal coil radius is necessary to significantly decrease the mutual inductance. An analytical function for the PERES Signal-to-noise ratio (SNR) is obtained based on the quasistatic method. Theoretical plots of SNR enhancement yielded 26% and 35% more SNR over the circular coil and phased-array coils. Imaging experiments were first performed using a spectroscopy phantom on a 1.5-T commercial imager. Subsequently, brain images of healthy volunteers were obtained. Clinical MR imager compatibility allows this resonator coil to be used with conventional pulse sequences and imaging protocols. This coil design offers a new alternative to existing surface coils because it significantly increases the SNR.