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 acute tubular necrosis (ATN) is still an important cause for postoperative malfunction of renal grafts, it would be useful to have a method predicting such a complication. We investigated the possibility to predict ATN by measuring the ratio of phosphomonoesters (PME, largely consisting of adenosine monophosphate) and inorganic phosphate (Pi) in the renal tissue, using 31P magnetic resonance spectroscopy (MRS) during the cold ischemia period. Assuming that this ratio reflects the tissue high-energy phosphate status, we studied five kidneys from living related donors (LRD), 28 kidneys from heart beating donors (HBD) and nine kidneys from non-heart beating donors (non-HBD). All kidneys were preserved with a phosphate free solution. We found an inverse relation between the time of 31P MRS and the PME/Pi ratio, suggesting a graded decay of tissue high energy phosphates during cold ischemia. The PME/Pi ratio was highest in grafts from LRD (2.65 +/- 0.50, no ATN), intermediate in grafts from HBD (1.65 +/- 0.41, 21% ATN) and lowest in those derived from non-HBD (1.05 +/- 0.47, 56% ATN). The differences in PME/Pi ratio between the groups was statistically significant (P < 0.01). Moreover, the ratio was significantly lower in grafts developing ATN (1.73 +/- 0.41 vs. 1.35 +/- 0.29 in the HBD group, 1.41 +/- 0.24 vs. 0.76 +/- 0.36 in the non-HBD group, P < 0.05). These observations point to a general relation between the pre-transplant kidney PME/Pi ratio and the development of ATN. However, the predictive value of a low PME/Pi ratio was too low (36%) to reliably predict development of ATN in individual cases.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Pre-transplantation assessment of renal viability with 31P magnetic resonance spectroscopy. 770 29

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

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