Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

As a pilot study, 31-P-spectra of the quadriceps femoris muscle (1.5T) and proton images of the right thigh (.5T) were performed in two cyclists (T) and two untrained (UT) subjects. During ischemia, while MRI did not show any change, phosphocreatine (PCr) concentration decreased and inorganic phosphate (Pi) increased. Recovery occurred within 3 minutes. Ergometric bicycle tests were performed outside the magnet. Submaximal workload (UT 150W/T 260W, 3.5 minutes) caused transient minimal changes in phosphorus metabolites. Supramaximal, partially anaerobic exercise (UT 320W/T 350W, 3.5 minutes) induced similar changes in heart rate, oxygen uptake rate, and plasma lactate in both groups. Decrease of the PCr/Pi ratio, however, was more pronounced in UT subjects and clearly lasted longer. If methodical problems can be resolved, combined MRS and MRI in whole body magnets may become a standard noninvasive modality, adding unique information on morphology (organ volume) and local metabolism to classic mechanical and global physiologic data.
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PMID:Combined use of magnetic resonance imaging (MRI) and spectroscopy (MRS) by whole body magnets in studying skeletal muscle morphology and metabolism. 404 94

The protective effect of FK506 on hepatocytes against ischemia and reperfusion injury was examined by evaluating the following: the high energy phosphorus metabolism obtained using 31P magnetic resonance spectroscopy (31P-MRS) and the tissue blood flow of the liver in ischemia and the reperfusion process, mitochondrial glutamic oxaloacetic transaminase (m-GOT) and glutamic pyruvic transaminase (GPT), the survival rates of the animals, a histological study and immunohistological staining for intercellular adhesion molecule-1 (ICAM-1) in the liver after ischemia. The rats were treated with FK506 1 mg/kg/day i.m. for 4 days before testing. Ischemia was induced by clamping the hepatoduodenal ligament for 30 min. In 31P-MRS, the recovery of the hepatic energy status after ischemia, evaluated by beta-ATP/inorganic phosphate (Pi), was significantly better in the FK506 group. It also coincided with the recovery of tissue blood flow monitored with a laser Doppler flowmeter. In the histological examination, the congestion observed in the periportal region of the control group was mild, while there was less induction of ICAM-1 in the endothelial cells of the portal veins and hepatic veins in the FK506 group. From these findings, we concluded that FK506 had a protective effect on hepatocytes against warm ischemia and reperfusion injury, and the mechanism for this could partially be attributed to improved tissue blood flow after ischemia by the modulation of immunological events.
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PMID:The effect of FK506 on warm ischemia and reperfusion injury in the rat liver. 753 46

To evaluate the efficacy of 31P magnetic resonance spectroscopy (31P MRS) as a diagnostic method for abnormal testicular function, we examined three conditions using rat testes, ischemia, irradiation, and hormone manipulation. 1) Ischemia: Immediately after clamping of the feeding vessels, ATP signals began to fall and disappeared within 60 minutes. With the release of blood supply after 3 hours of ischemia, ATP appeared within 2 hours. However, after more than 4 hours of ischemia, ATP did not recover within 2 hours and the testis became necrotic after 1 week. 2) Irradiation: 31P MRS of the testis 2 weeks after irradiation with 10 Gy., 9 MeV showed a significant decrease (P < 0.05) in the PME/beta-ATP ratio from 1.30 +/- 0.11 (control level) to 1.11 +/- 0.12 and a decrease in PME/PDE ratio from 1.43 +/- 0.17 to 1.13 +/- 0.20. However 3 weeks later, the PME/beta-ATP ratio recovered to a control level. 3) Hormone manipulation: In the testes 5 weeks after weekly intramuscular injections of estradiol benzoate and testosterone enanthate, PDE/beta-ATP ratio significantly increased (P < 0.01) from 0.83 +/- 0.09 (control level) to 1.03 +/- 0.19. 31P MRS is a non-invasive method for evaluation of various testicular abnormalities, and ATP signals may be useful to evaluate an acute ischemic change for example testicular torstion and the changes of PME, PDE signals may be useful parameters in the assessment of the status of spermatogenesis.
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PMID:[Experimental studies on evaluation of rat testicular function by 31P magnetic resonance spectroscopy]. 778 56

Single voxel 1H double spin-echo MR spectroscopy was used to examine 15 cases of brain metastasis of mammary carcinoma (18 lesions) in relation to Gd-DTPA enhanced MR imaging. For lesions larger than 50% of MRS voxel size, there was significant correlation between Gd-DTPA-enhanced MRI signal and MRS-detected signal of choline (Cho) containing compounds (r = 0.86, P < 0.01; n = 8). The observed loss of correlation when including the smaller lesions was overcome by correcting for partial volume effects (r = 0.69, P < 0.002; n = 18). Metastasis spectra showed increased Cho compared with control spectra, except for those lesions showing detectable lactate (Lact) signal. The detection of Lact in four of the larger lesions coincided with comparatively low levels of creatine (Cr) and Cho and heterogeneous Gd-DTPA enhancement (Cr) and Cho and heterogeneous Gd-DTPA enhancement (ring-enhancement). It was concluded that in brain metastases of mammary carcinoma Lact represents a product of ischemia preceding/during tissue decay resulting in central necrosis, rather than tumor specific metabolism resulting in increased glycolysis.
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PMID:Correlation between choline level and Gd-DTPA enhancement in patients with brain metastases of mammary carcinoma. 780 55

Restoration of the ATP level after brief ischemia is limited by slow de novo ATP synthesis and substrate loss in a salvage pathways for ATP synthesis, and complete recovery requires several days in the stunned heart. Adenosine is a substrate for myocardial ATP synthesis. We measured myocardial ATP in both ex vivo and in vivo experiments by 31P magnetic resonance spectroscopy (31P-MRS) and investigated the time course of ATP content recovery after application of adenosine. Guinea-pig perfused hearts were subjected to 30 min of global ischemia and reperfused for 3 h with 50 microM adenosine. The ATP level increased from 54 +/- 5% to 117 +/- 4% of the pre-ischemic value (p < 0.01). In dogs, we occluded the left anterior descending coronary artery for 40 min to produce regional ischemia. Afterwards, we administered 100 mumol/h adenosine into the left ventricle for 2 h. ATP levels increased from 63 +/- 4% to 77 +/- 5% of the pre-ischemic value with adenosine (p < 0.05). However, ATP levels did not increase for a few hours after reperfusion both ex vivo and in vivo. Our 31P-MRS studies demonstrated that brief ischemia depressed ATP levels and that administration of adenosine accelerated ATP formation in post-ischemic hearts.
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PMID:Time course of the recovery of adenosine triphosphate content with adenosine in post-ischemic hearts--a 31P magnetic resonance spectroscopy study. 796 8

The effects of ulinastatin (UTI) on rat renal energy metabolism during ischemia and reperfusion were studied by 31P nuclear magnetic resonance spectroscopy (31P MRS) in vivo. Rat kidney was exposed to ischemia for 30 min by clamping the abdominal aorta above the renal arteries. Pre-ischemic administration of UTI inhibited the decline of intracellular pH (pHi) during ischemia and improved the recovery of renal energy metabolism and pHi after reperfusion. This result suggests that UTI might inhibit anaerobic metabolism during renal ischemia and an improve energy metabolism during reperfusion. 31P MRS provided a unique tool to study intact cellular function continuously in noninvasive fashion, allowing assessment of metabolic function during ischemia and after reperfusion.
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PMID:[Effects of ulinastatin on rat renal energy metabolism around ischemia studied by 31P MRS]. 825 74

The effect of warm ischemia and reperfusion injury in the regenerating rat liver after portal vein branch ligation (PBL) was examined by monitoring hepatic high energy phosphorous metabolism using in vivo Phosphorus-31 Magnetic Resonance Spectroscopy (31P-MRS). On 14 days after 70% occlusion of the portal vein, energy metabolism of non-occluded lobe of the liver was evaluated by measuring the ratio of beta-ATP to Pi obtained using 31P-MRS. During 30min-ischemia, beta-ATP/Pi dropped down similarly below the limit of observation in both of control and regenerating liver. However, after reperfusion, in the regenerating liver, the earlier and better recovery of beta-ATP/Pi was observed compared with the control. In the any examination of m-GOT, GPT, increase in enzyme level was apparently restrained in the PBL group. On the pathological examination, centrilobular necrosis and hepatocyte degeneration were remarkable in the normal liver, while in the regenerating liver, these changes were slight. In conclusion, these results suggest that reperfusion injury observed in the regenerating liver seems to be reduced compared with that in the normal liver. Functional and structural changes in the regenerating liver could be claimed as a course of this observation. However, to understand the mechanism, further study will be needed both in morphological and biochemical aspect.
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PMID:[Warm ischemia and reperfusion injury in the regenerating rat liver]. 827 66

We present a method for the direct correlation of quantitative changes in lactate concentration and intracellular pH during global ischemia in the perfused rat heart using rapidly interleaved 31P MRS and water-suppressed 1H MRS acquisitions. The ischemic myocardial buffering capacity was determined and found to be consistent with previous experimentation.
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PMID:Study of ischemic myocardial buffering capacity in perfused rat heart through rapidly interleaved 1H and 31P MRS measurements. 837 64

In 14 in situ canine renal transplants, intracellular phosphorus metabolites were evaluated by phosphorus-31 magnetic resonance spectroscopy (31P-MRS), performed using surface coils to investigate the usefulness of this technique for assessing renal viability in situ. Group I control kidneys (n = 5) were autografts, as were Group II (n = 5) kidneys: the latter group were subjected to surgically induced vascular ischemia and thrombosis. Group III kidneys (n = 4) were rejecting allografts. Renal flow and function, as measured by 99mTc-DTPA, and findings on histologic examination were correlated with 31P-MRS spectra. Group I kidneys showed excellent viability on both 99mTc-DTPA studies and biopsy evaluation, and their 31P-MRS-derived ratios of phosphomonoesters/inorganic phosphate (PME/Pi) and adenosine triphosphate/Pi (ATP/Pi) were high (1.32 +/- 0.23 and 0.90 +/- 0.36, respectively). In contrast, Group II kidneys demonstrated poor flow and function, histologic evidence of severe ischemia from venous and arterial thrombosis, and significantly (P < 0.005) less viability than controls, as monitored by 31P-MRS PME/Pi (0.58 +/- 0.30) and ATP/Pi (0.20 +/- 0.13) ratios. Group III kidneys also demonstrated poor flow and function with 99mTc-DTPA, and the associated histologically injury was noted to be caused by accelerated rejection and severe vascular damage. PME/Pi (0.24 +/- 0.22) and ATP/Pi (0.10 +/- 0.01) ratios were also significantly (P < 0.005) less than those in controls, reflecting nonviability. The 31P-MRS-derived PME/Pi and ATP/Pi ratios enable a qualitative noninvasive assessment of blood flow-dependent renal viability, but with currently used localization techniques the differentiation between severe ischemia and severe acute rejection was not possible.
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PMID:Assessment of in situ renal transplant viability by 31P-MRS: experimental study in canines. 838 89

Skin 31P MRS measurements might detect metabolic damage from irradiation, chemotherapy, or ischemia. Although rat and cadaver data have demonstrated this potential (C.D. Cuono, et al., Plast. Reconstr. Surg. 81, 1-11 (1988), H.W. Klein, et al., Ann. Plast. Surg. 20, 547-551 (1988)), few studies of in vivo phosphorus human skin spectra have been published (A. Zemtsov, et al., J. Dermatol. Surg. Oncol. 15, 1207-1211 (1989), A Zemtsov, et al., J. Am. Acad. Dermatol. 30, 959-965 (1994)), and those likely reflect underlying muscle as much as skin. To separate 31P skin and muscle spectra, we have developed a unique two-layer "flotation" phantom for mapping coil sensitivity and an associated semiempirical two-power RF depth-resolved technique. Phantom and method have been applied in a study of 17 normal volunteers to obtain human in vivo 31P skin spectra uncompromised by muscle contamination and to quantitate ratios of major phosphometabolites. Skin results consistently showed low ratios of phosphocreatine (PCr) to adenosine triphosphate (ATP), high levels of phosphomonoester (PME), P(i), and phosphodiester (PDE) relative to PCr, and demonstrated a shift in pH toward greater alkalinity, compared to that with simultaneous muscle results.
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PMID:In vivo phosphorus spectroscopy of human skin. 862 82


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