Metabolite mapping of human filarial parasite, Brugia malayi with nuclear magnetic resonance

Metabolite mapping of human filarial parasite, Brugia malayi was carried out in vitro as well as in situ in host Mastomys coucha by ³¹P nuclear magnetic resonance (NMR) spectroscopy. Detection of parasites by visualizing contrast spots due to pathologic changes was observed by ¹H magnetic resonance imaging (MRI). Major metabolites of adult B. malayi observed by ³¹P-NMR spectroscopy were of sugar phosphates (SP), phosphomonoesters (PME), glycerophosphoryl-ethanolamine (GPE), -choline (GPC), phosphoenolpyruvate (PEP), inorganic phosphate (Pi), nucleoside diphosphosugar and nucleotides-mono, -di and -tri phosphates. PEP and GPC were present in high concentration; PEP being the major energy reservoir and GPC the major phospholipid in this species of filaria. The ³¹P NMR spectra of testis of mastomys, showed seven major peaks of SP, PME, phosphocreatine (PCr), phosphodiesters (PDE), Pi, and nucleotides di- and tri-phosphates. The ³¹P-NMR spectra of testis of B. malayi infected animal also consisted of seven major peaks with significant decrease in the SP and PME peak showing changes in the carbohydrate and lipid metabolism of filaria infected testis. Thus, in vivo ³¹P MRS provided a non-invasive assessment of tissue bioenergetics and phospholipid metabolism.     

In vivo 31P MRS of human brain at high/ultrahigh fields: a quantitative comparison of NMR detection sensitivity and spectral resolution between 4 T and 7 T

The primary goal of this study was to establish a rigorous approach for determining and comparing the NMR detection sensitivity of in vivo ³¹P MRS at different field strengths (B₀). This was done by calculating the signal-to-noise ratio (SNR) achieved within a unit sampling time at a given field strength. In vivo ³¹P spectra of human occipital lobe were acquired at 4 and 7 T under similar experimental conditions. They were used to measure the improvement of the human brain ³¹P MRS when the field strength increases from 4 to 7 T. The relaxation times and line widths of the phosphocreatine (PCr) resonance peak and the RF coil quality factors (Q) were also measured at these two field strengths. Their relative contributions to SNR at a given field strength were analyzed and discussed. The results show that in vivo ³¹P sensitivity was significantly improved at 7 T as compared with 4 T. Moreover, the line-width of the PCr resonance peak showed less than a linear increase with increased B₀, which leads to a significant improvement in ³¹P spectral resolution. These findings indicate the advantage of high-field strength to improve in vivo ³¹P MRS quality in both sensitivity and spectral resolution. This advantage should improve the reliability and applicability of in vivo ³¹P MRS in studying high-energy phosphate metabolism, phospholipid metabolism and cerebral biogenetics in the human at both normal and diseased states noninvasively. Finally, the approach used in this study for calculating in vivo ³¹P MRS sensitivity provides a general tool in estimating the relative NMR detection sensitivity for any nuclear spin at a given field strength.     

1D and 2D solid state NMR investigations of the framework structure of As-synthesized AlPO4-14

The framework structure of As-synthesized A1PO₄-14 has been investigated with a combination of different one-dimensional ²⁷Al and ³¹P solid state NMR techniques and ²⁷Al/³¹P double resonance methods. The results are found to be fully consistent with the assumed structural model. ²⁷Al MAS and DOR experiments at three different magnetic field strengths together with simulations show the presence of two tetrahedral sites, one pentacoordinated and one octahedral aluminum site. The ²⁷Al quadrupolar coupling constants and the ³¹P isotropic chemical shifts of the tetrahedral sites correlate well with tetrahedral shear-strain parameters and mean P-O-A1 bond angles, respectively. These correlations allow one to assign all of the NMR resonances to specific T-sites in the proposed framework structure. The assignments are then further confirmed by the application of three different two-dimensional heteronuclear correlation methods (i.e., ²⁷Al → ³¹P TEDOR, CP, and INEPT) which reveal the connectivities between AlO_x and PO₄ polyhedra. The two-dimensional INEPT experiment is applied here for the first time in the solid state.     

Alzheimer''s disease histologically proven studied by MRI and MRS: Two cases

Two patients affected by severe Alzheimer's disease (AD) were investigated by MRI and image-guided ³¹P MRS. In one case, ¹H MRS was additionally performed. In both cases the diagnosis of AD was confirmed, post mortem, by the pathologist. The spectral parameters of the ³¹P MR spectra were estimated by fitting the ³¹P MR signals in the time domain. Our ³¹P MRS results suggest that it is possible to detect the membrane catabolism, as indexed with the level of PDE resonances visible in in vivo ³¹P MRS, at least in severe AD cases. The ¹H spectrum from AD brain showed a marked decrease of NAA signal respect to choline.     

紫杉醇治疗小鼠S180肉瘤的体内31P MRS研究

为了研究紫杉醇治疗小鼠S180肉瘤的³¹P MRS参数的变化及这些参数的变化是否早于常规观察的瘤体积的变化.方法:利用表面线圈³¹P NMR方法,研究小鼠皮下接种的S180肉瘤.结果:用药48h后给药组的PCr/Pi、β-NTP/Pi、PME/β-NTP比值与对照组有显著性差别(P<0.05),而肿瘤体积在给药组和对照组之间无显著性差别,³¹P MRS参数的变化早于瘤体积变化.结论:小鼠S180肉瘤³¹P MRS不仅可以给出定量的结果,而且可以较早地显示出治疗的效果.     

P and N solid-state nuclear magnetic resonance spectroscopic study of some monophospha-λ-azenes

³¹P Cross-polarization magic-angle spinning nuclear magnetic resonance (CP-MAS NMR) spectra of eight monophospha-λ⁵-azenes were measured at room temperature. Three of these compounds, with 2-OH substituents, are in principle capable of taking part in the equilibrium process. However, only the open form, tautomer A, is found in the present study. ¹⁵N CP-MAS NMR spectra support the results. The most shielded component of the ³¹P chemical shift tensor lies in the direction of the P=N bond.     

高场磁共振成像1H/31P双调谐射频线圈研究进展

在众多可产生磁共振现象的原子核中,¹H核凭借其在生物体中含量高、磁共振信号强的优势,成为磁共振成像的主要研究对象．但其它杂核在生命科学相关研究中同样具有不可替代的独特性,如³¹P核广泛参与了生物体内的能量代谢过程,是非质子成像研究领域的重要内容．MRI向更高场强的发展使得杂核成像逐渐普及,其核心部件是高质量的¹H/³¹P双调谐射频线圈．本文总结了与¹H/³¹P双调谐射频线圈相关的研究与应用,展示了9.4 T下小鼠脑的质子磁共振成像及磁共振磷谱,并讨论了高场¹H/³¹P双调谐射频线圈的潜在应用价值．     

Quadrupole effects of spin-3/2 nuclei on the solid-state magic-angle spinning nuclear magnetic resonance spectra of spin-1/2 nuclei Deviations from first-order theory and implications concerning the sign of the indirect coupling constant

The effect of the interaction between spin-3/2 and spin-1/2 nuclei on solid-state magic-angle spinning nuclear magnetic resonance (MAS NMR) spectra of the latter is studied in cases where deviations from first-order theory are expected. A comparison is made between the exact and first-order perturbation approaches. Both dipolar and indirect (iso- and anisotropic) coupling interactions are considered. Implications regarding ¹³C,^35,37Cl, ³¹P,^63,65Cu and ¹¹⁹Sn,^35,37Cl cases are discussed. It is shown that in the latter two cases the sign of the indirect coupling constant J can be derived.     

Si CP/MAS NMR of phosphorus-bearing organosilicon compounds

While liquid-state ²⁹Si NMR of phosphorus-bearing organosilicon compounds with more than one phosphorus per molecule can take advantage of the presence of J-coupling ⁿJ(³¹P²⁹Si) for purposes of structural assignment from J-coupling patterns, conventional ²⁹Si CP/MAS spectra of such molecular solids do not reveal structural details in a straightforward manner. For such compounds it is necessary to obtain ²⁹Si CP/MAS spectra under conditions of simultaneous ¹H- and ³¹P-high power decoupling in order to derive reliable ²⁹Si chemical shift information. ²⁹Si CP/MAS NMR spectra, obtained with and without ³¹P high power decoupling during the acquisition time, of several organosilicon compounds containing Si_xP_y (x = 1 −10, y = 1 −10) moieties are reported.     

A study of T1-weighted 31phosphorus MR-spectroscopy from patients with focal and diffuse liver disease.

³¹P-MR-Spectroscopy was performed in 28 patients with focal (n = 23) and diffuse (n = 5) liver disease and in 18 healthy volunteers. The spectra were obtained with a whole body scanner operating at 1.5 T by using a surface coil. To get T₁-weighted ³¹P-spectra a short TR of 600 msec was taken, because T₁-weighted spectra of focal liver disease were more significantly different from spectra from healthy volunteers than density weighted ones. The VOI from patients with focal superficial alterations showed a mean volume of 172 ml, with diffuse liver disease 196 ml, and from volunteers 158 ml. Focal tumors filled up the VOI on an average of 70%. This investigation demonstrated that PME/β-ATP- and PDE/β-ATP-ratios were sensitive indicators for focal liver disease. As a result of this study we could establish a significant increase of PME/β-ATP- (0.75 ± 0.30) and PDE/β-ATP-ratios (1.68 ± 0.62) in patients with superficial focal liver metastases (n = 19) compared to the control group (PME/β-ATP: 0.49 ± 0.17, PDE/β-ATP: 1.24 ± 0.24; t-test: p < 0.02). Patients with a hemangioma (n = 1), liver infarction (n = 1), empyema of gallbladder (n = 1) and a hepatic involvement by a malignant lymphoma (n = 1) showed a similar increase of PME/β-ATP and/or PDE/β-ATP. Up to now spectral changes seemed to be non-specific. The ratios of ³¹P metabolites of the cirrhoses (n = 4) and the fatty liver (n = 1) did not show any characteristic changes versus the volunteers.     

脑科学研究中的质子磁共振波谱方法

核磁共振（NMR）波谱作为一种操作简单、高效且重复性良好的技术手段,在脑科学领域的应用日益广泛,尤其是离体核磁共振氢谱（¹H NMR）和活体核磁共振氢谱（¹H MRS）.¹H NMR和¹H MRS在实验设计、样品预处理、数据处理等方面各有优劣、各擅胜场.本综述主要从适用范围、样品预处理、数据处理分析等方面,对二者在方法学层面的研究现状进行总结和讨论,以期为脑科学领域的研究者进行大脑代谢相关研究时提供一定的参考和帮助.     

金属核的磁共振研究*Ⅱ含磷配体铂(Ⅱ)络合物的195Pt和31P-NMR谱

本文测定了12个含苯基环戊基磷、亚磷酸、卤素等配体的铂(Ⅱ)络合物的¹⁹⁵Pt、³¹P-NMR谱,考察了溶剂、浓度、温度对¹⁹⁵Pt谱的影响,研究了¹⁹⁵Pt、³¹P化学位移、偶合常数与络合物几何构型的关系及对卤素的依赖关系。讨论1,2-丙二胺溶液中络合物³¹P谱的变化,以及各种含亚磷酸配体的铂络合物¹⁹⁵Pt和³¹P谱的变化。     

A study of the S levels and the analogue levels of P by the P(He, d)S reaction

The ³¹P(³He, d)³²S reaction has been studied with high resolution at 12 MeV bombarding energy. A detailed level scheme for ³²S has been determined up to an excitation energy of 9.5 MeV revealing several previously unobserved states. The l_p values and absolute spectroscopic factors extracted from a DWBA analysis of the experimental deuteron angular distributions have provided information on the wave functions for the T = 0 states as well as for the T = 1 isobaric analogue states of ³²P. A comparison between the present data and those of previous experiments is made, and the results are discussed in terms of existing theoretical work in this mass region. Information on Coulomb displacement and symmetry energies is also extracted.     

Residual 31P, 35,37Cl dipolar coupling in 31P MAS spectra of chlorocyclophosphazenes

In ³¹P MAS NMR spectra of chlorocyclophosphazenes, characteristic splittings have been observed for PCl or PCl₂ groups. At different applied magnetic fields, the fine structure and total width of the patterns change in a characteristic way, demonstrating that the splittings are due to indirect spin–spin and residual dipolar interactions with the chlorine nuclei directly bonded to phosphorus. For trans-nongeminal N₃P₃Cl₃(NMe₂)₃ and N₃P₃Cl₆ as examples, the spectra have been analyzed to obtain information on chlorine nuclear quadrupole coupling constants and ^35,37Cl, ³¹P indirect spin–spin coupling constants. Neglect of these interactions may result in misinterpretations of the multiplicity in ³¹P MAS spectra of chlorophosphazenes.     

Spin-lattice relaxation times and nuclear overhauser enhancement effect for P metabolites in model solutions at two frequencies: Implications for in vivo spectroscopy

The relaxation time T₁ values and nuclear Overhauser enhancement factor for ³¹P signal were determined in model solutions of metabolites ATP, PCr and Pi, and AMP at two frequencies and in H₂O and ²H₂O solutions. The data were analyzed to resolve the contribution of different relaxation mechanisms. A knowledge of NOE is important in the light of recent applications of double resonance methods to enhance the sensitivity of in vivo ³¹P spectroscopy. The results show that chemical shift anisotropy is the dominant mechanism for ³¹P in ATP at the high field, whereas the dipolar interaction mechanism is the main feature for the ³¹P relaxation of PCr and Pi. The dipolar mechanism responsible for NOE originates from interactions of solvent water with ³¹P moiety. Implications for in vivo spectroscopy are indicated.     

S-烷基-O-(邻烷氧基羰基苯基)-硫(赶)代磷酰胺的NMR研究

本工作记录了六种通式为H₂N RS P=O-O-COOR'(R=Me,Et,i-Pr,n-Pr;R'=Me,Et,i-Pr)的有机磷农药的¹H、¹³C、³¹P NMR谱及¹³C,¹H异核化学位移相关谱。确定了各¹H、¹³C、³¹P的化学位移值和¹H-¹H、³¹P-¹H、³¹P-¹³C的偶合常数。讨论了核磁参数与分子结构和运动以及³¹P化学位移与生物活性之间的关系。     

Kinetics of H→P cross-polarization in human trabecular bone

Bloch-decay and cross-polarization (CP) ³¹P nuclear magnetic resonance (NMR) spectra of healthy human trabecular bone were acquired under magic-angle spinning (MAS) at 3 kHz. A single peak at 3.1 ppm was detected. Variable-contact time ¹H → ³¹P CP experiments revealed three signal components growing at various rates. The fast, moderate and slow components were assigned and assessed in P atom % to proton-rich (24%), hydroxyapatite (58%) and proton-deficient (18%) phosphate domains, respectively. Examination of CP kinetics is useful for the chemical characterization of bone tissue.     

人淋巴瘤白血病细胞系Molt-4的31P核磁共振研究

用³¹P核磁共振(NMR)观察了人淋巴瘤白血病细胞系Molt-4的³¹P谱.NMR测试温度为37℃、20℃和4℃时,随着测试时间增长,细胞³¹P谱中ATP峰降低,无机磷峰升高,细胞³¹P谱的变化随测试温度降低依次减缓.实验温度为4℃,从收集细胞至开始NMR累加在30min内,NMR累加在60min内,获得活细胞的稳定的³¹P谱.根据细胞内无机磷的化学位移数值,对细胞内pH值进行了测定.     

O-乙基O-芳基N-异丙基硫代磷酰胺酯类化合物的除草活性与其31P化学位移的关系

本文测定了标题所示一类化合物的³¹P的化学位移,并讨论了它与取代基电子性间存在如下的关系δP=-0.9193σ+3.5891F+66.5385提出了³¹P化学位移与此类化合物的除草活性间存在一定的相关性,其关系如下PI₅₀=-0.9025π²+0.9017π-0.5600E_s-0.1620△δP+0.8445I+4.2514并对此关系的适用性及存在偏差作了初步讨论。     

活体肝胵Fasciola hepatica及其高氯酸萃取物的31P及13C NMR研究

本工作报道了用³¹P NMR谱定量分析活体肝胵Fasiciola hepatica中含磷化合物的实验方法及一些初步结果,测定了活体肝胵体内含磷化合物的弛豫时间T₁,观察了无灌注循环系统时肝胵体内pH值变化。利用高氯酸萃取物测得的³¹P NMR谱,定出了各谱峰的归属,观察了用含糖及缺糖培养液培养的肝胵糖类养料的代谢变化,并利用¹³C NMR谱肯定了肝胵体内主要含磷化合物之一的α-甘油磷酰胆碱³¹P NMR谱峰的归属。