Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0016382 (flushing)
 6,387 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Phosphorus nuclear magnetic resonance (31P NMR) can be used as a non-destructive method for the simultaneous observation of the major phosphate-containing metabolites (ATP, ADP, nucleotide monophosphate, Pi, sugar phosphate) and intracellular pH in isolated rat kidney. The time course of changes in these metabolites and in cellular pH in the ischaemic kidney are examined at two temperatures and in the presence of different flushing media. ATP is rapidly depleted while the pH change is slower and shows biphasic behaviour. Pi production and total nucleotide (ATP and ADP) depletion also occur on the same time-scale as the tissue acidification. The relation of these observations to tissue viability is discussed and the possibility of extending the measurements to human organs is considered.
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PMID:Non-destructive measurement of metabolites and tissue pH in the kidney by 31P nuclear magnetic resonance. 4 1

The metabolic response of the rat liver to flushing and reflushing with Marshall's solution at pH 7.2 or pH 7.8 has been studied by 31P nuclear magnetic resonance spectroscopy. The changes in intracellular pH, inorganic phosphate, ATP and phosphomonoesters have been determined from the 31P spectra. We show that the intracellular pH at any stage of the flushing protocol is largely independent of the pH of the medium when using these solutions. However, we demonstrate that there are differences between the efficiency of the two solutions in respect of the rates of hydrolysis of ATP and accumulation of phosphomonoesters. There were also differences in the response of the livers upon reflushing--those livers reflushed at pH 7.2 resynthesized ATP from a lower initial concentration to achieve ATP concentrations similar to those restored in livers reflushed at pH 7.8. These trends were mirrored in the responses of the phosphomonoester peaks (which contain a contribution from AMP). We conclude that short-term control of liver metabolism during hypothermia is possible by use of solutions of different pH, but that for longer-term storage, other approaches may be necessary to maintain metabolic integrity.
NMR Biomed 1989 Sep
PMID:Biochemical consequences of reflushing hypothermically-stored liver with fresh cold perfusate. Studies on rat liver using 31P NMR spectroscopy. 264 Dec 99

Rabbit hearts were subjected to 24-h cold ischaemic storage (at 0 degree-2 degrees C in melting ice) after initial flushing with either St Thomas' cardioplegic solution (STS) or modified lactobionate/raffinose solution (LR), and the status of phosphorylated energy metabolites was measured by 31phosphorus nuclear magnetic resonance (P NMR) spectroscopy. In both groups signals for ATP and phosphocreatine (PCr) were still detectable by 31P NMR after 24 h, and there was significantly more ATP in the LR group (P < 0.01). The hearts were then subjected to coronary reperfusion via an aortic cannula using the same storage solution (either STS or LR) at 6 degrees-8 degrees C, which was oxygenated. In both groups PCr recovered within 30 min of cold reperfusion, and by 60 min PCr was significantly higher in the LR group (P < 0.001). Also, levels of ATP were maintained at higher values during cold reperfusion i the LR group. These studies suggest two important points: (1) the general supply of phosphorylated high-energy intermediates of hearts during cold ischaemic storage is better preserved using LR, and (2) brief cold reperfusion may be used to restore energy metabolism in hearts before re-implantation.
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PMID:Resuscitation of cardiac energy metabolism in the rabbit heart by brief hypothermic reperfusion after preservation studied by 31P NMR spectroscopy. 788 58

Carcinoids, tumors arising from enterochromaffin cells, represent the most common type of gastrointestinal endocrine neoplasm; they are often multiple and may appear anywhere in the gut. Carcinoid tumors may also occur in bronchi and ovaries. Classic symptomatology includes secretory diarrhea, flushing, edema, bronchospasm and cutaneous teleangectasias; however, over 30% of patients with demonstrably elevated serotonin levels may not exhibit any symptoms at all. The diagnosis of carcinoid tumor is typically made by measurement of 24-hour urinary excretion of 5-hydroxyindoloacetic acid. Commonly, tumor localisation is established with CT, US, NMR and arteriography. MIBG scintigraphy is also used to visualize tumors deriving from neuroendocrine cells as carcinoid. These tumors may express somatostatin receptors located on the cell surface. Therefore 111In Octreotide (Octreoscan), a somatostatin analogue, can be employed for tumor localisation. A 32-years-old man with liver metastases secondary to a carcinoid tumor of unknown origin is presented. Classic carcinoid symptoms were absent. Diagnosis was supported by elevated values of urinary 5-hydroxyindolocetic acid and liver fine-needle aspiration. Abdominal US and CT scan detected only liver masses but not the primary tumor. Arteriography was not performed. 131I MIBG and 111I octreotide scans both failed in locating the primary cancer too; only the second tracer showed marked uptake in liver metastases. Beside localization, these two tracers give also informations about the following therapy especially in malignant tumors where local resection isn't an adequate treatment.
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PMID:131I MIBG/111In octreotide mismatch in a patient with liver metastases secondary to a carcinoid of unknown origin. 853 97

Lactate-edited 1H NMR difference spectra have been acquired from intact rat liver tissue following flushing and preservation in ice. A peak, initially at 1.26 ppm, was seen to increase in the liver tissue with preservation time. This peak was assigned to lactate, despite the fact that its chemical shift was initially shifted by approximately -0.1 ppm relative to an externally added standard. The assignment was based on the following: (a) the peak increased over a 24-h ischemic storage period; (b) it was coupled to a signal 2.78 +/- 0.02 ppm upfield; and (c) a parallel increase in lactate was noted in perchloric acid extracts of tissue from the same liver. An additional peak, assigned to alanine, was also observed during storage and was also shifted by approximately -0.1 ppm. Inclusion of dimethyl sulfoxide, which readily permeates liver tissue, demonstrated that this chemical shift alteration was a tissue-specific effect. These results demonstrate that 1H NMR spectroscopy of intact liver tissue during hypothermic ischemia is possible, though chemical shift assignments should be made with caution.
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PMID:Proton nuclear magnetic resonance spectroscopy of lactate production in isolated rat liver during cold preservation. 867 59

Twenty patients with the diagnosis of pheochromocytoma were studied from January 1990 to January 1998. Nineteen patients had a pathologic investigation performed. The mean age of patients was 49 +/- 16 years (range: 24-71 years), 8 males and 12 females. Nine cases corresponded to adrenal and eleven to extra-adrenal (paragangliomas) pheochromocytomas. The anatomic location was similar in both adrenal glands and for paragangliomas the cervical location predominated. The most consistent clinical finding in our patients was maintained arterial hypertension, followed by headache, palpitations and flushing. Biochemically, an increase in urine catecholamine levels or their metabolites was found in 82.2%. The clonidine test was very useful, particularly for cases where biochemical results were discrepant. CT, NMR and gammagraphy with 123I-MIBG have a high sensitivity for locating pheochromocytomas. NMR and gammagraphy with 111In-pentetreotide located cases in which CT or 123I-MIBG were negative. Preoperative treatment with adrenergic alpha-blockers allowed to surgery with no arterial tension complications. Only one patient with multiple abdominal paragangliomas relapsed. No differences regarding clinical manifestations, biochemical parameters or imaging studies were found between pheochromocytomas and paragangliomas, except their location.
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PMID:[A comparative study of 9 cases of adrenal pheochromocytoma and 11 cases of extra-adrenal pheochromocytoma]. 1043 7

We present the application of flow NMR in an automated, open-access environment. The adjustment of parameters affecting the selection of the correct sample size, the elimination of carry-over, and the optimization of sample recovery are addressed. Advantages of this method include ease of use, elimination of NMR tubes, an delimination of handling errors that can result in the contamination of the probe. Sample throughput is similar to instruments using a conventional autosampler (for Bruker instruments, a BACS) although the time used for shimming the sample can be eliminated when the sample solvent does not change. The key feature of our methodology is that only one push solvent is used. This has major advantages over methods that switch solvents because there is no extensive flushing required between solvents and the deuterated push solvent, deuterium oxide, is economical. The disadvantage is the need to maintain the push and transfer solvents and usually the loss of the exchangeable protons that the sample may have. The protocol we present, using a single push solvent, contributes to the application of flow NMR in hands-on medicinal chemistry environments.
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PMID:Application of flow NMR to an open-access pharmaceutical environment. 1271 56

Structure elucidation of natural products usually relies on a combination of NMR spectroscopy with mass spectrometry whereby NMR trails MS in terms of the minimum sample amount required. In the present study, the usefulness of on-line solid-phase extraction (SPE) in LC-NMR for peak storage after the LC separation prior to NMR analysis is demonstrated. The SPE unit allows the use of normal protonated solvents for the LC separation and fully deuterated solvents for flushing the trapped compounds to the NMR probe. Thus, solvent suppression is no longer necessary. Multiple trapping of the same analyte from repeated LC injections was utilized to solve the problem of low concentration and to obtain 2D heteronuclear NMR spectra. In addition, a combination of the SPE unit with a recently developed cryoflow NMR probe and an MS was evaluated. This on-line LC-UV-SPE-NMR-MS system was used for the automated analysis of a Greek oregano extract. Combining the data provided by the UV, MS, and NMR spectra, the flavonoids taxifolin, aromadendrin, eriodictyol, naringenin, and apigenin, the phenolic acid rosmarinic acid, and the monoterpene carvacrol were identified. This automated technique is very useful for natural product analysis, and the large sensitivity improvement leads to significantly reduced NMR acquisition times.
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PMID:LC-UV-solid-phase extraction-NMR-MS combined with a cryogenic flow probe and its application to the identification of compounds present in Greek oregano. 1461 13

In this study, the hyphenation of LC-SPE-NMR-MS at 500 MHz was applied to the structural elucidation of a low concentrated paracetamol metabolite present in human urine. Single or multiple peak trapping of the mass detected metabolite on SPE cartridges was employed to increase the sensitivity and quality NMR measurement over the conventional LC-NMR method. After the elution of the metabolite from the SPE cartridge to the NMR flow probe using deuterated acetonitrile for initial NMR investigation, the fraction was revovered by flushing the sample out of the NMR probe head with nitrogen gas. On the recovered fraction, high resolution FT-ICR-MS measurements were conducted, giving exact mass information about the unknown metabolite. In addition, a cryogenic NMR micro probe head was used to enhance the sensitivity of the NMR measurement by a factor of 5 in order to run 2D experiments for structural elucidation of the unknown metabolite. The combination of both MS and NMR results, led unequivocally to the elucidation of the structure as the ether glucuronide of 3-methoxyparacetamol.
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PMID:Characterization of a paracetamol metabolite using on-line LC-SPE-NMR-MS and a cryogenic NMR probe. 1559 67

In this paper, we describe approaches that make RP LC-SPE-NMR simpler, and in our opinion, result in more reliable methods for trapping and subsequent transfer of separated trace-level compounds to the NMR. An SPE unit based on a commercially available, low dead-volume 10 port high-pressure column selector gives the possibility of trapping compounds on nine individual SPEs that have standard fittings. This allows the operator to employ specific stationary phases that are not available as SPEs in commercially available LC-SPE-NMR systems. Multiple trappings of small compounds like monuron, 1-(4-chlorophenyl)-3-methylurea, and 4-chlorophenylurea were easily performed employing a porous-carbon SPE material. The system was optimized to elute the SPE-trapped compounds to the NMR probes in as small a volume as possible using back-flushing. The proper match of NMR probe volume and SPE column inner diameter and elution volume was discussed, as well as the necessity of drying loaded SPEs prior to NMR transfer when using porous-carbon SPE material.
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PMID:An alternative multiple-trapping LC-SPE-NMR system. 1739 89


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