Patients with renal failure undergoing hemodialysis often have muscle cramps during and after the dialysis therapy. Muscle cramps are defined as the sudden onset of a prolonged involuntary muscle contraction accompanied with severe pain, resulting in early termination of a HD session and inadequate dialysis. The etiology of the cramps is unknown and effective anti-cramp medicine is not available. We have hypothesized that water-soluble vitamins are deficient in HD patients. Accordingly, we administrated biotin to 14 patients who had frequent muscle cramps during HD sessions. Oral administration of 1 mg/day biotin promptly reduced the onset and the severity of cramps in 12 patients both during and after HD. Then, the plasma biotin levels were measured by an enzyme-linked immunosorbent assay method (ELISA) in HD patients, including 14 patients with cramps and 13 patients without cramps, and 11 healthy volunteers. Plasma biotin levels were elevated in 27 HD patients at baseline compared with healthy volunteers [451 (377 -649) vs. 224 (148 -308) ng/l, median (lower-upper quartiles); p < 0.0001]. Unexpectedly, among the 14 cramp patients, the biotin levels were significantly higher in biotin-ineffective 7 patients than biotin-effective 7 patients [1,064 (710 -1,187) vs. 445 (359 -476) ng/l; p < 0.001]. Thus, the biotins measured by ELISA may consist of not only intact biotin but also its metabolites that do not function as a vitamin. In conclusion, biotin administration is one choice to relieve HD patients from muscle cramps regardless of their elevated plasma biotin levels.
NMR measurements coupled with pattern-recognition analysis offer a powerful mixture-analysis tool for latent-feature extraction and sample classification. As fundamental applications of this analysis for mixtures, the 1 H spectra of 176 kinds of green, black, oolong and other tea infusions were acquired by a 500 MHz NMR spectrometer. Each spectrum pattern was analyzed by a multivariate statistical pattern-recognition method where Principal Component Analysis (PCA) was used in combination with Soft Independent Modeling of Class Analogy (SIMCA). SIMCA effectively selected variables that contribute to tea categorization. The final PCA resulted in clear classification reflecting the fermentation and processing of each tea, and revealed marker variables that include catechin and theanine peaks.
IntroductionNMR-based Metabolomic analysis has mainly been used for toxicology or drug discovery.1,2 Significant metabolic responses have been detected on various bio samples with the dose, injection of toxins or high-salt diet. Recently, various life-style related diseases, such as hypertension, diabetes, and hyperlipidemia, have become serious topics of concern. To acquire potential information on disease status, including presymptomatic data, the detection of any profile difference from the normal in natural conditions is essential. To understand the progress of disease metabolism, we performed an experiment with 20 model rats: 10 rats that were spontaneously hypertensive (SHR/Izm) and 10 rats that were normal (Wistar Kyoto, WKY). The two strains' urine samples were collected under conditions of minimized intentional stress, such as on impact, dose, special diet and fasting. 3,4 The 1D 1 H-NMR spectra for the urine samples were measured. All of the spectra were analyzed by a pattern recognition method and classified by their pattern differences. It is notable that there is no need to assign each peak or to identify the compounds in the spectrum, which can be recognized as a profile histogram. 5 To investigate the reflection of the metabolic balance in excretions, the pattern recognition method is a faster and more straightforward approach than conventional NMR structure analysis. Experimental Animal handling and sample collectionTen rats each of 9-week-old males of WKY and SHR/Izm strain were purchased from SHIMIZU Laboratory Supplies Co., Ltd. The rats were housed by Bio-Science Center of KAC Co., Ltd. (Kyoto, Japan) in metabolic cages for 1 week acclimatization. All of the studies were conducted using the same basic protocol in that a standard solid diet, CRF-1 (Oriental Yeast Co. Ltd.) was given to all animals and free access to food and water was permitted. A temperature of 23 ± 2˚C and a relative humidity of 50 ± 10% were maintained with a 12 h light/12 h dark cycle. Urine samples were collected from each 10-week-old of WKY strain (average b.p. 105/75 mmHg, wt 265 g) and SHR/Izm strain (average b.p. 171/140 mmHg, wt 255 g), during the daytime (14:00 -18:00) and nighttime (18:00 -9:00), respectively. The samples were sent to us maintained at 0 -4˚C, and then measured within 2 days. In our laboratory, after centrifuging, 200 µL of a phosphate buffer solution was added to 400 µL of rat urine, with which 5% D2O and 0.1% (w/v) NaN3 were mixed, to obtain pH 7.4. Each 600 µL of the solution was used for an NMR measurement. NMR spectroscopyThe 1 H NMR spectra were acquired using a 500 MHz JEOL ECA spectrometer at 25˚C. Each spectrum consisted of 16 K complex data points with a spectrum width of 5 kHz, where each spectrum was accumulated by 128 scans with an acquisition time of 1.75 s, and a recycle delay of 5 s per scan. The detection pulse flip angle was set to 45˚. A pre-saturation sequence was used to suppress the water signal. NMR data reduction procedures and pattern recognition analysisEach NMR spectrum wa...
Recently, the ratio of patients with diabetes mellitus (DM) among hemodialysis (HD) patients has increased to become the largest sub-population. Their prognoses are significantly worse than those of patients without diabetes (non-DM). In the present study, 10 DM patients who did not take meals and 10 non-DM patients who took meals during HD sessions were investigated. The time courses of the change in plasma levels of metabolites during HD were determined. DM patients exhibited decreased plasma levels of lactate, pyruvate and alanine and dramatically increased levels of ketone bodies. At the end of HD, the plasma levels of lactate, pyruvate, alanine and ketone body were 0.46 ± 0.07, 0.026 ± 0.01, 0.12 ± 0.04 and 0.26 ± 0.04 mM (mean ± standard error), respectively. The profile was ‘hypolactatemia and hyperketonemia’, indicating non-homeostasis. Glycolysis and tricarboxylic acid cycle were suppressed, and the oxidation of fatty acid was accelerated, indicating starvation, even though high amounts of glucose (150 mg/dl) in dialysate were supplied continuously to the bloodstream. In contrast, the plasma levels of lactate, pyruvate, and alanine in the non-DM patients were increased, with the levels of ketone body remaining low during HD to maintain homeostasis, indicating accelerated glycolysis. Furthermore, their plasma levels of insulin increased from 8.1 ± 1.4 to 19.8 ± 3.4 μU/ml, which indicated endogenous secretion stimulated by glucose in dialysate and meal intake. In contrast, in the DM patients, the levels decreased from 19.2 ± 3.4 to 5.5 ± 1.1 μU/ml. This value was the lower limit of the normal range. The depletion of the insulin through extracorporeal circulation may inhibit the transportation of glucose from the blood into the muscles, with the consequence of cell starvation. Such cell starvation along with lipolysis every two days may accelerate proteolysis and affect the prognosis of DM patients.
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