摘要:

AbstractThis review assesses the progress of NMR in the field of hemorheology, i.e., the assessment of the mechanical and physical characteristics of flowing blood. The review deals with the intrinsic rheological properties of the red cell and its constituents (membrane, cytoplasm), which are dominant in the microcirculation, and a section concerns the investigation of the cell/cell interaction phenomenon, known to give rise to the complicated non‐Newtonian behavior of blood under most of the flow conditions encountered in the blood circulation using NM

ISSN:0952-3480    

DOI:10.1002/nbm.1940020102

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY

摘要:

AbstractVolume‐selective water‐suppressed proton spectra were recorded from live human brain and muscle at 1.5 T by combining a stimulated echo acquisition mode pulse sequence for localization and two saturation pulses for water suppression (Frahmet al., SMRM Abstracts, 1987). Metabolite signals were observed in voxels of size 4–64 cm3. Signals from —CH3and β‐CH2ofN‐acetylaspartate, N—CH3and N—CH2of phosphocreatine/creatine, —N(CH3)3of choline and inositol protons were visible in the brain spectra from normal subjects. Differences in metabolite levels were observed between gray and white matters of brain from their water‐suppressed spectra. Peaks from N—CH3of phosphocreatine/creatine and —+N(CH3)3of choline and carnitine were present in normal muscle spectra along with several res

ISSN:0952-3480    

DOI:10.1002/nbm.1940020103

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY

摘要:

AbstractThe effects of nutritional manipulation and subsequent chemotherapeutic treatment upon growth and metabolism of a transplanted rat rhabdomyosarcoma were investigated byin vivo31P NMR spectroscopy. Nutritional manipulation was accomplished by administration of a protein deprived diet containing no protein and 75.5% glucose. After 5 days the protein deprived rats (PD rats) were nutritionally replenished with a normal protein diet containing 27% protein and 47.3% glucose. Twenty‐four hours after nutritional replenishment the PD rats and continuously well‐fed controls (NP rats) received methotrexate (MTX, 30 mg/kg, i.p.).31P NMR spectroscopy of the tumors 24 h after MTX administration showed a decreased ratio of nucleoside triphosphates to inorganic phosphate (referred to as ‘ATP/P1ratio’) in PD rats in contrast to an unchanged ATP/P1ratio in the NP controls. At the time of MTX administration the PD rats had a significantly lower tumor pH than the NP group (6.75 ± 0.03 [SEM] vs 6.95 ± 0.04;p<0.02). Tumor response in the PD group was significantly (p<0.01) enhanced compared to the NP group. These findings indicate that a period of dietary protein deprivation combined with a high glucose load and followed by nutritional replenishment impairs tumor metabolism. The altered metabolic status is expressed by acidification of the tumor and distinct changes in ATP/P1ratio and appears to relate to an enhanced susceptibility to MTX che

ISSN:0952-3480    

DOI:10.1002/nbm.1940020104

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY

摘要:

AbstractThe biochemistry of hepatic injury and recovery from preservation for transplantation was studied in rat liver perfusedin vitrowith erythrocytes. ATP and its metabolites, inorganic phosphate (P1) and pH were quantitated as often as every 2.5 min by31P NMR spectroscopy during preservation and recovery. Release of the hepatocellular enzymes, lactate dehydrogenase V (LDV) and aspartate aminotransferase (AST) were also measured. The duration of preservation with Collins' solution, the standard clinical preservative, affected the rate of recovery of ATP and monophosphate esters (MP), which include AMP + IMP, and the final recovery of Pi, but not of ATP. The difference between Collins' and Ringer's lactate solution, a poor preservative, became more apparent as preservation time increased. The differences included (1) pH at the end of preservative infusion; (2) pH between 0 and 2.5 min of reperfusion; (3) the MP increase (AMP + IMP) at the end of 13 h of preservation; (4) rate of recovery of ATP after preservation; (5) final ATP recovery during reperfusion; (6) LDV after 13 h of preservation. These biochemical differences between good and poor preservation form a rational basis for prediction of liver failure after transplantation and for tests of the quality of new preservatives.

ISSN:0952-3480    

DOI:10.1002/nbm.1940020105

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY

摘要:

AbstractThe myeloproliferative leukemic virus (MPLV) induces within 2–3 weeks a massive infiltration of the adult mouse liver by hematopoietic leukemic cells. Since the metabolism of the infiltrated organ might be correlated with an interaction of two cell populations, it was decided to study the isolated hematopoietic cells separately. The metabolism of these cells embedded in an agarose gel and perfused with labeled substrates was investigated using31P and13C NMR. Using [1‐13C]glucose as precursor, sequential13C NMR spectra showed that the hematopoietic cells were able to store glucose as [1‐13C]glycogen and to metabolize it through the glycolytic pathway to give [3‐13C]lactate as sole end‐product. The liver neoglucogenic substrates: [2‐13C]pyruvate and [3‐13C]alanine are not metabolized by these cells. This suggests that the tricarboxylic acid cycle was not efficient. To investigate further the glycolytic properties of the cells, 10 mMsodium azide was added to the medium containing [1‐13C]glucose. When compared to the aerobic conditions, a 40% decrease of nucleotides (0.10 vs 0.17 m̈mole NTP/109cells), a degradation of [1‐13C]glycogen and an increase of ca 35% of the glycolytic rate were observed. The analysis of13C NMR spectra of the perfusates at the end of the perfusion indicates a total conversion of [1‐13C]glucose into [3‐13C]lactate and [3‐13C]pyruvate under anaerobic conditions. These results permit a better understanding of the metabolism of the perfused leukemic livers which are extensively infiltrated by t

ISSN:0952-3480    

DOI:10.1002/nbm.1940020106

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY

摘要:

AbstractEpendymoblastoma tumour bearing mice were treated with sarcosinamide‐CNU and compared with untreated mice with regard to tumour growth, pathological examinations and levels of phosphorylated metabolites measured byin vivonuclear magnetic resonance spectroscopy. The response to the drug was demonstrated by its effect on tumour growth and with pathological examinations. Spectra evolution was different from controls for only four treated tumours out of eigh

ISSN:0952-3480    

DOI:10.1002/nbm.1940020107

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY

摘要:

AbstractA new method for selective observation of scalar coupled metabolites by either zero‐quantum coherence transfer or polarization transfer with concurrent water suppression in a single acquisition was developed. Gaussian shaped RF pulses were used to selectively generate multiple‐quantum and zero‐quantum coherence in the metabolite of interest, single quantum (including water) and double quantum coherences were then dephased under the influence of aB0field gradient and the surviving zero‐quantum coherence was converted to observable metabolite signal. The duration of the gradient application and the frequency and angle of the final selective read pulse determined whether a polarization transfer or a coherence transfer signal was observed.Water suppression factors of around 8000 were achieved which allowed operation of the receiver at high gain levels resulting in greatly improved signal to noise in the metabolite spectra. The CH3and CH resonances of lactate in a mouse brain homogenate were selectively edited and the method was also applied to selective editing of

ISSN:0952-3480    

DOI:10.1002/nbm.1940020108

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY

摘要:

AbstractDirect quantification of the inhibitory effects of orally administered drugs (sorbinil, cyclandelate and sulindac) on aldose reductase activities in rat brains was performed non‐invasively using the 3‐fluoro‐3‐deoxy‐D‐glucose (3‐FDG)19F NMR spectroscopic technique. Quantitative data obtained directly from the target organ (brain) allowed for unprecedentedly accurate analysis of drug effects in the brainin vivo. Sorbinil, a potent aldose reductase inhibitor, exhibited a classic monophasic organ response, whereas cyclandelate and sulindac showed biphasic suppression patterns. The latter indicate that there are metabolites of these drugs which possess aldose reductase inhibitory activities. The estimated potency of aldose reductase inhibition for each of the three drugs in this study was significantly discrepant from thein vitrostudies indicating the complicated nature of the bioavailability of a pharmaceutical agentin vivo, especially where pharmacologically active metabolites of a given drug are involved. Our method allows for a direct quantitative assay and hence the most reliable technique for evaluating aldose reductase inhibitory activities in the

ISSN:0952-3480    

DOI:10.1002/nbm.1940020109

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY

ISSN:0952-3480    

DOI:10.1002/nbm.1940020101

出版商:John Wiley&Sons, Ltd.    

年代:1989

数据来源: WILEY