左卡尼汀在维持性血液透析患者治疗中的应用

目的 观察长期维持性血液透析患者（MHD）静脉补充左卡尼汀的临床疗效及不良反应。方法选择60例病情稳定2年以上的患者，随机分为两组，治疗组于每次透析结束时静脉注射左卡尼汀1g，对照组静脉注射等量的生理盐水，共应用12周。结果静脉补充左卡尼汀时患者症状明显改善，促红细胞生成素用药量明显减少，血红蛋白、血球压积有升高，血浆白蛋白及转铁蛋白均有升高。药物不良反应轻，停药后可缓解。结论左卡尼汀能有效地治疗维持性血液透析患者左卡尼汀的缺乏。     

左卡尼汀对治疗老年维持性血液透析患者低血压和肌肉痉挛的疗效观察

目的观察静脉补充左卡尼汀对老年血液透析患者透析中低血压、肌肉痉挛的影响。方法 31例维持性血液透析患者每次透析结束后应用左卡尼汀1.0 g静脉注射,12周后观察比较患者治疗前后低血压、肌肉痉挛的发生情况。结果注射左卡尼汀可以明显降低患者透析中低血压和肌肉痉挛的发生率。结论左卡尼汀可安全有效地改善患者低血压和肌肉痉挛症状。     

左卡尼汀对维持性血液透析患者左心肥厚的影响

目的:研究左卡尼汀对心功能正常的维持性血液透析患者左心室肥厚(LVH)的治疗作用.方法:选择沈阳军区总医院血液净化中心透析超过6个月、心功能正常的维持性血液透析患者60例,分为治疗组30例和对照组30例.在常规血液透析基础上,治疗组每次透析结束后,静注左卡尼汀1.0 g,对照组每次透析结束后,静注等体积的生理盐水,时间为6个月.治疗前后检测血浆左卡尼汀、血钙、血磷、红细胞压积水平及促红素的用量.心脏超声检测间隔舒张期末期厚度、左室后壁厚度、左心室舒张期末内径、左心室收缩末期内径、左室重量、左室重量指数.结果:治疗组血浆左卡尼汀由(49.3±8.2) μmol/L增加至(95.3±22.2)μmol/L(P<0.01),左室重量指数由(151.8±21.2)g/m2降至(134.3±16.2)g/m2(P<0.01),而对照血浆左卡尼汀浓度及超声心动图参数无明显变化.治疗组促红素的用量少于对照组,血细胞比容和血压在研究期间无明显变化.结论:心功能正常的维持性血液透析患者LVH多见,左卡尼汀可以减轻心功能正常的血液透析患者LVH.     

左卡尼汀对血液透析患者心功能的影响

目的 研究脑钠肽在血液透析患者心力衰竭时血浆中的水平及左卡尼汀的治疗作用.方法 检测49例血液透析心力衰竭患者透析前后脑钠肽水平,以30例无心力衰竭患者作为对照;心力衰竭组25例患者随机入组接受左卡尼汀治疗,比较治疗前后患者心功能及脑钠肽水平的变化.结果 心力衰竭组和无心力衰竭组患者透析后血浆脑钠肽水平均明显下降,差异有统计学意义（P〈0.05）;左卡尼汀组心功能改善并且脑钠肽水平下降较对照组均有统计学差异（P〈0.05）.结论 血液透析可以促使心力衰竭患者血浆脑钠肽水平下降;左卡尼汀对接受血液透析的心力衰竭者有治疗作用.     

左卡尼汀在老年患者透析中防治顽固性低血压的疗效观察

目的 探讨左卡尼汀在防治老年透析患者顽固性低血压的疗效.方法 选择血液透析中容易发生低血压的老年患者30例,将患者平均分成两组,即使用左卡尼汀注射液组和常规组,在透析中分别对两组患者进行血压监测和临床症状观察.结果 左卡尼汀组明显比常规组低血压的发生率低.结论 在透析结束时对患者应用左卡尼汀,可以有效地改善老年患者在透析过程中低血压的发生,降低透析患者的死亡率.     

左旋卡尼汀改善维持性血液透析患者脂代谢紊乱的临床观察

尿毒症维持性血液透析（MHD）患大多存在脂代谢紊乱，其原因和影响因素是复杂的，既有尿毒症毒素的作用，也有透析过程中应用葡萄糖、肝素的影响，还有因透析过程中肉碱丢失，而使组织和血浆中肉碱浓度降低因素的影响。左旋卡尼汀作为脂肪酸代谢中的关键物质在脂代谢调节方面起着重要作用。作自2002年6月至2005年6月观察了左旋卡尼汀注射剂对MHD患血脂变化的影响，旨在探讨其对脂代谢紊乱的改善情况。     

左卡尼汀对尿毒症血液透析患者QT离散度的影响

目的观察左卡尼汀对尿毒症血液透析患者QT离散度的影响。方法选择58例行维持性血液透析治疗6个月以上病情稳定的尿毒症患者,随机分成治疗组（30例）和对照组（28例）。两组患者均给予常规治疗,血液透析频率每周3次,每次4小时。治疗组除常规治疗外,另加用左卡尼汀治疗。用药前和治疗3个月后分别检测两组患者透析前的血红蛋白、尿素氮、血肌酐、血钾、血钙、心电图,测量并计算QT离散度及校正的QT离散度。结果治疗前治疗组与对照组相比,QT离散度及校正的QT离散度差异无统计学意义（P〉0.05）;治疗后治疗组与对照组相比,QT离散度及校正的QT离散度有显著下降,差异具有统计学意义（P〈0.01）;治疗组治疗前后QT离散度及校正的QT离散度差异具有统计学意义（P〈0.01）;治疗组治疗前后血红蛋白浓度差异具有统计学意义（P〈0.01）。结论尿毒症维持性血液透析患者补充左卡尼汀能显著改善QT离散度。     

左卡尼汀用于临床配合透析治疗尿毒症患者的应用价值探究

选取2013年2月~2014年7月收治的68例尿毒症患者。根据治疗方法的不同分为观察组和对照组各34例。观察组给予左卡尼汀配合血液透析治疗,对照组给予常规血液透析治疗。比较两组患者贫血改善情况、治疗前后血浆蛋白、红细胞比容增加情况。结果观察组治疗后红细胞比容增加为31.4±5.7%,高于对照组的25.2±4.1%;观察组治疗后血红蛋白为98.9±14.5g/L,高于对照组的81.2±12.9g/L;观察组治疗后贫血改善总有效率为94.12%,明显高于对照组的73.53%。左卡尼汀配合透析治疗尿毒症患者具有较好疗效,可增加血红蛋白含量,提高红细胞比容,改善贫血,值得临床应用并大力推广。     

左卡尼汀对改善维持性血液透析老年患者心功能的效果分析

探讨左卡尼汀对改善维持性血液透析老年患者心功能的临床疗效。选取2013年10月~2015年10月于我院进行维持性血液透析的老年患者80例作为研究对象,按照随机数字分配原则将其平均分为对照组和观察组。两组患者血液透析基本治疗一致,其中观察组患者于每次透析结束回血前3min从血路管静脉端注入左卡尼汀1g,每周进行三次,三个月为一个疗程,对照组患者采用同样方式给予等量生理盐水。观察比较两组患者治疗前后的心脏指数,左心功能指数,每分钟心搏出量、每搏心输出量等指标。两组患者组内比较,观察组患者治疗后心功能改善情况明显优于治疗前(P0.05);两组患者组间比较,观察组患者治疗后心功能明显优于对照组,差异具有统计学意义(P0.05)。在维持性血液透析老年患者中应用左卡尼汀可以有效的保护患者心肌,显著的改善患者的心功能。     

左卡尼汀配合腹膜透析治疗尿毒症20例

目的：研究静脉注射左卡尼汀（左旋肉碱）对尿毒症腹膜透析患者卡尼汀缺乏症的治疗作用。方法：将40例尿毒症腹膜透析患者随机分成治疗组（20例）和对照组（20例），治疗组每日静脉注射左卡尼汀1．0g(5mL),疗程3个月。对照组每日静脉注射生理氯化钠5mL，连续3个月。结果：1个疗程后治疗组体力、精神状态、食欲明显改善，营养参数明显提高，脂类代谢得以部分纠正，治疗组和对照组相比有显著的统计学差异（P＜0．01）。结论：静脉注射左卡尼汀可改善腹膜透析患者卡尼汀缺乏的相关并发症。     

Biotin ameliorates muscle cramps of hemodialysis patients: a prospective trial

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.     

Increase in and clearance of cell-free plasma DNA in hemodialysis quantified by real-time PCR.

BACKGROUND: Recently cell-free plasma DNA has been described as a marker of apoptosis during hemodialysis (HD), but little is known about how different dialysis membranes may contribute to this process or whether pre-HD levels are restored afterwards. Here we evaluate the influence of the dialysis membrane on cell-free plasma DNA levels and investigate the clearance of plasma circulating DNA after HD. METHODS: Cell-free plasma DNA was measured using a real-time quantitative PCR for the beta-globin gene. Reference values for plasma DNA were established in a group of 100 healthy voluntary blood donors. Pre- and post-HD levels were also measured in 30 patients with end-stage renal disease on regular HD (52 sessions; 104 samples). The sessions lasted for 2.5-5 h. Different dialysis membranes were compared: high-flux (n=37) vs. low-flux (n=15) and polysulfone (n=42) vs. modified cellulose (n=10). To determine the time at which pre-HD levels are restored, DNA was quantified in serial plasma samples obtained from 10 of these 30 patients, just before and immediately after HD, as well as at 30, 60 and 120 min after HD. RESULTS: Reference plasma DNA values for healthy blood donors ranged from 112 to 2452 gEq/mL (median 740 gEq/mL). Cell-free plasma DNA levels significantly increased during HD (Wilcoxon test for paired samples, p<0.0001), with increases of more than four-fold observed in 75% of the patients after HD. There was no significant linear association between the length of the HD session (between 2.5 and 5 h) and the increase in cell-free plasma DNA concentration (Pearson correlation). No significant differences were observed between different types of membranes (Mann-Whitney U-test). Plasma DNA returned to pre-HD levels by 30 min after HD, regardless of the starting concentration. CONCLUSIONS: Plasma DNA levels significantly increase after a conventional 2.5-5-h HD session. Therefore, HD patients require special consideration for correct interpretation of plasma DNA concentrations. This parameter can be considered a reliable diagnostic tool for certain pathologies when measured at least 30 min after a HD session without further complications. The different dialysis membranes used in this study had no influence on cell-free plasma DNA concentrations, so the level of circulating DNA is not an appropriate marker of dialysis membrane biocompatibility.     

Pharmacokinetics of L-carnitine in patients with end-stage renal disease undergoing long-term hemodialysis

OBJECTIVE: L-Carnitine is an endogenous molecule involved in fatty acid metabolism. Secondary carnitine deficiency may develop in patients with end-stage renal disease undergoing long-term hemodialysis because of dialytic loss. In these patients L-carnitine can be administered to restore plasma and tissue levels. The objective of this study was to evaluate the pharmacokinetics of intravenous L-carnitine in patients undergoing long-term hemodialysis. METHODS: Twelve patients undergoing three dialysis sessions/week received L-carnitine intravenously (20 mg x kg(-1)) at the end of each dialysis session for 9 weeks. Plasma samples were analyzed for L-carnitine, acetyl-L-carnitine, and total carnitine by HPLC. RESULTS: Under baseline conditions, the mean +/- SD predialysis plasma concentration of L-carnitine was 19.5 +/- 5.6 micromol/L, decreasing to 5.6 +/- 1.9 micromol/L at the end of the dialysis session. These concentrations were substantially lower than endogenous levels in healthy human beings. Under baseline conditions the extraction ratios of L-carnitine and acetyl-L-carnitine by the dialyser were 0.74 +/- 0.07 and 0.71 +/- 0.11, respectively. During repeated dosing, there was accumulation of L-carnitine in plasma, and after 9 weeks of dosing, the predialysis and postdialysis plasma levels were 191 +/- 54.1 and 41.8 +/- 13.0 micromol/L, respectively. The predialysis and postdialysis plasma levels of L-carnitine decreased once dosing was ceased but had not returned to pretreatment levels after 6 weeks. CONCLUSION: The study demonstrated that removal of L-carnitine by hemodialysis is extremely efficient and that patients undergoing hemodialysis had plasma concentrations that were substantially lower than normal, particularly during dialysis. During repeated administration of L-carnitine, the predialysis and postdialysis concentrations of the compound increased steadily, reaching an apparent steady state after about 8 weeks. It is proposed that this accumulation arose from the distribution of L-carnitine into a deep tissue pool that includes skeletal muscle.     

不同血液透析模式对透析中低血压的影响

目的 比较低温+超滤曲线HD、钠曲线+超滤曲线HD、低温+钠曲线HD、低温+钠曲线+超滤曲线HD、常规HD+上机前口服米多君与常规HD在透析过程中低血压发生的情况.方法 对经常出现血液透析相关性低血压的20例维持性血透患者,依次实施常规HD、低温+超滤曲线HD、钠曲线+超滤曲线HD、低温+钠曲线HD、低温+钠曲线+超滤曲线HD、常规HD+上机前口服米多君,每人每种方式实施四周的治疗剂量,观察比较6种模式透析低血压的发生情况.结果 低温+超滤曲线组、钠曲线+超滤曲线组、低温+钠曲线组低血压的发生率低于常规组(P＜0.05),低温+超滤曲线+钠曲线组、上机前口服米多君组低血压的发生率显著低于常规(P＜0.01),低温+超滤曲线组、钠曲线组+超滤曲线、低温+钠曲线组,之间比较低血压的发生率无差异(P＞0.05),低温+超滤曲线+钠曲线组与上机前口服米多君组低血压的发生率无差异(P＞0.05),低温+超滤曲线组、钠曲线组+超滤曲线、低温+钠曲线组与低温+超滤曲线+钠曲线组、常规透析+上机前口服米多君组之间低血压的发生率经统计学处理均有显著差异(P＜0.01).结论 在体重增长、超滤率大致相等情况下,低温+超滤曲线+钠曲线组与常规HD+上机前口服米多君组低血压的发生率在统计学无意义(P＜0.01),提示这两种透析模式预防透析相关性低血压的效果最佳,可以根据患者的经济及对透析模式的耐受情况具体选择.

Abstract：

Objective Low -temperature + UF curves HD, sodium curve + UF curves HD, low -temperature + sodium curve HD, low - temperature + sodium curve HD + UF curves HD, HD + oral administration of midodrine before dialysis' and conventional HD were comprised to observe hypotension occurrence during hemodialysis. Methods Twenty patients were selected who occurred related hypotension frequently. They were treated with the following proposals: conventional HD, low -temperature + UF curves HD, sodium ctuve+UF curves HD, low - temperature + sodium curve HD, low - temperature + sodium curve + UF curves HD, conventional HD + oral administration of midodrine before dialysis. Each patient's treatments lasted four weeks under each dialysis mode. The incidence of hypotension were observed and compared among six dialysis modes. Results The incidence of hypotension in low - temperature + UF curves, sodium curve + UF curves, low - temperature + sodium curve groups were lower than that of ( P ＜ 0. 05), the incidence of hypotension in lowtemperature + sodium curve + UF curves, oral administration of midodrine before dialysis groups were significant lower than that of conventional group (P＜0.01) . The incidences of hypotension among low- temperature + UF curves HD group, sodium curve + UF curves group and low - temperature + sodium curve group were no difference ( P ＞ 0. 05) . The incidences of hypotension between low - temperature + sodium curve + UF curves group and oral administration of midodrine group were no difference ( P ＞ 0. 05) . There was significant difference by statistical treatment on incidences of hypotension between low - temperature + UF curves group, sodium curve + UF curves group, low- temperature + sodium curve group and low- temperature + sodium curve + UF curves group, conventional HD + oral administration of midodrine before dialysis group (P＜0.01). Conclusions The incidences of hypotension in low - temperature + sodium curve + UF curves group and conventional HD + oral administration of midodrine before dialysis group were no statistical significance ( P＜0. 01). It hints that the effect of preventing dialysis - related hypotension is the best under two modes. The patients can choose these modes according to their economy and endurance.     

Normal regulation of elevated plasma ghrelin concentrations in dialysis patients

BACKGROUND: Chronic renal failure is often associated with malnutrition, and malnourished patients are subject to increased morbidity and mortality. Therefore plasma concentrations of the stomach-derived peptide hormone ghrelin, which has been shown to exert potent GH-releasing and appetite-stimulating effects, were determined and correlated with nutritional parameters. METHODS: Twenty-four patients (15 male, 9 female) undergoing hemodialysis (HD) were studied. In addition, six patients were studied before and one hour after ingestion of a meal and five were studied immediately before and at the end of the dialysis session. RESULTS: Chronic renal insufficiency was associated with significantly elevated ghrelin levels (320.1 +/- 57 fmol/mL vs. 75.6 +/- 12.4 fmol/mL in controls; p < 0.007). Plasma ghrelin concentrations were also significantly higher in the 16 normal-weight patients than in the eight overweight or obese patients (399.6 +/- 76.3 fmol/mL vs. 161.1 +/- 41.3 fmol/mL; p < 0.03). Ingestion of food induced a decrease in five out of six patients tested (mean 242.3 +/- 66.5 fmol/mL vs. 186 +/- 30.7 fmol/mL; n.s.). HD also resulted in a significant decrease of elevated ghrelin concentrations: ghrelin was in the normal range at the end of HD in four of the five patients tested. Plasma ghrelin concentrations did not correlate with nutritional parameters except for cholinesterase which was negatively correlated to ghrelin. CONCLUSION: Plasma ghrelin concentrations are elevated in HD. The fact that ghrelin concentrations are higher in normal-weight than in overweight or obese HD patients and suppressed after ingestion of a meal suggests that the regulation of ghrelin release is retained in HD patients, albeit shifted to a higher level.     

Carnitine and left ventricular function in haemodialysis patients

Left ventricular function was non-invasively studied in 28 randomly selected haemodialysis patients before and after administration of L-carnitine, 2 g i.v. three times per week or saline in a double blind designed study over a six-week period. Cardiac function variables showed no relationship to muscle (vastus lateralis) and plasma carnitine concentrations. No apparent deficiency in muscle carnitine was found, whereas total plasma carnitine was lower in female patients than in female controls, p less than 0.002. The echocardiographic left ventricular end-diastolic diameter was initially increased in about one third and the ejection fraction was depressed in about one fifth of the patients. An increased A:H ratio was found in 15%. Systolic time intervals were deranged in 30% of the patients. After carnitine administration, marked increases of muscle and plasma carnitine levels were found, p less than 0.01, but no effects were recorded in any of the cardiac tests. Muscle carnitine increased from 14.6 mmol/kg dry weight to a median of 23.7 mmol/kg. We found no support for the hypothesis that carnitine depletion is responsible for cardiac dysfunction in haemodialysis patients.     

Homocysteine, vitamin B12, and serum and erythrocyte folate in peritoneal dialysis and hemodialysis patients.

BACKGROUND: Plasma homocysteine (Hcy) is an independent risk factor for cardiovascular disease. High levels of plasma Hcy have been observed in end-stage renal disease patients. Few studies have compared peritoneal dialysis (PD) and hemodialysis (HD) patients and few data are available on erythrocyte folate (ery-F) levels in dialysis patients. OBJECTIVES: To evaluate plasma Hcy concentrations, vitamin B12 (B12), and folate status in dialysis patients; to analyze the possible causes of high Hcy levels; to follow up changes in folate and B12 concentrations after 6 months. DESIGN: A cross-sectional observational study. SETTING: Nephrology division and laboratory of hematology in a university and clinical research hospital. PATIENTS: The study included 82 patients treated with PD for 37 + 37 months and 70 patients treated with HD for 136 + 95 months. LABORATORY METHODS: Plasma Hcy was measured by the immunoenzymatic IMx Hcy FPIA method (Abbott Laboratories, Diagnostic Division, Abbott Park, IL, U.S.A.), serum folate (s-F) and ery-F by the Stratus folate fluorometric enzyme-linked assay, and B12 by the Stratus vitamin B12 fluorometric enzyme-linked assay (DADE-Behring, Newark, DE, U.S.A.). RESULTS: Ninety-six percent of PD and 97% of HD patients had Hcy levels above the cutoff (13.5 micromol/L). Homocysteine level was higher in HD than in PD patients, while the prevalence of hyperhomocysteinemia was similar with the two techniques. Erythrocyte folate was significantly higher in PD (1333 +/- 519 pmol/L) than in HD (1049 +/-511 pmol/L, p < 0.01). Statistically significant correlations were observed between Hcy and B12, s-F, ery-F, and dialysis duration. Multivariate analysis showed a strong correlation between s-F and Hcy. After 6 months there were no differences in Hcy, B12, s-F, and ery-F levels. CONCLUSIONS: Plasma Hcy levels were high in more than 95% of our dialysis patients, with no relation to the type of dialysis. Vitamin B12 and folate were normal in the majority of our patients. However, serum folate was the major determinant of Hcy levels. Such a relation between Hcy and folate suggests that levels of folate within the reference interval are inadequate for dialysis patients.     

Oral carnitine therapy in children with cystinosis and renal Fanconi syndrome.

11 children with either cystinosis or Lowe's syndrome had a reduced content of plasma and muscle carnitine due to renal Fanconi syndrome. After treatment with oral L-carnitine, 100 mg/kg per d divided every 6 h, plasma carnitine concentrations became normal in all subjects within 2 d. Initial plasma free fatty acid concentrations, inversely related to free carnitine concentrations, were reduced after 7-20 mo of carnitine therapy. Muscle lipid accumulation, which varied directly with duration of carnitine deficiency (r = 0.73), improved significantly in three of seven rebiopsied patients after carnitine therapy. One Lowe's syndrome patient achieved a normal muscle carnitine level after therapy. Muscle carnitine levels remained low in all cystinosis patients, even though cystinotic muscle cells in culture took up L-[3H]carnitine normally. The half-life of plasma carnitine for cystinotic children given a single oral dose approximated 6.3 h; 14% of ingested L-carnitine was excreted within 24 h. Studies in a uremic patient with cystinosis showed that her plasma carnitine was in equilibrium with some larger compartment and may have been maintained by release of carnitine from the muscle during dialysis. Because oral L-carnitine corrects plasma carnitine deficiency, lowers plasma free fatty acid concentrations, and reverses muscle lipid accumulation in some patients, its use as therapy in renal Fanconi syndrome should be considered. However, its efficacy in restoring muscle carnitine to normal, and the optimal dosage regimen, have yet to be determined.     

应用超滤曲线和血容量监测预防透析反应的护理研究

目的 观察采用不同超滤(ultrafihration，UF)曲线模式对血液透析症状性低血压发生的影响，并评估相对血容量(relativebloodvolume，RBV)监测对血透症状性低血压的预报作用。方法 选择68例既往有血透症状性低血压的血透患，分别应用6种不同超滤曲线模式，共进行238次透析。UF0(超滤率恒定)，UF1(超滤率呈线性递减)，UF2(阶梯式超滤率下降)，UF3～UF5(高超滤率与最小超滤率交替)，并监测RBV值的变化。结果 采用UF0和UF1曲线模式时症状性低血压发生率均明显低于UF2、UF3、UF4、UF5曲线模式，其中UF1曲线模式发生率最低；与UF0和UF1模式相比，肌肉痉挛、呕吐、疲劳、头痛在UF2～UF5有较高的发生率。发生低血压症状时患RBV常低于无症状时的RBV。临界最小相对血容量(mRBV)一般低于88％时，预示可能有症状性低血压的发生。结论 采用线性递减超滤率模式有助于减少血透症状性低血压的发生；监测RBV变化有助于预报血透低血压的发生。     

Plasma betaine concentrations correlate with plasma cortisol but not with C-reactive protein in an elderly population

Abstract Background: Low plasma betaine concentrations are a feature of seriously ill patients. Increased dietary betaine intake has been associated with lowered systemic inflammation. We aimed to compare plasma cortisol (a stress marker) and C-reactive protein (an inflammation marker) as statistical predictors of plasma betaine concentrations. Methods: Plasma carnitine, cortisol and C-reactive protein concentrations, other biochemical measures and urine betaine excretion, were compared with plasma betaine concentration by correlation and in multiple regression models, using morning blood and urine samples from 64 ambulant elderly subjects and from 55 patients admitted to hospital with hip fractures. Results: In the ambulant elderly without acute trauma, plasma cortisol (with negative coefficients) and carnitine (with positive coefficients) statistically predicted plasma betaine concentrations. C-reactive protein was not a predictor. In the patients, the significant predictors were plasma carnitine (positive coefficient) and plasma homocysteine (negative coefficient) and C-reactive protein again was not a predictor. In regression models using combined patient and control data there were large ranges of both cortisol and especially C-reactive protein; cortisol and homocysteine (negative coefficients) and carnitine (positive coefficient) were significant predictors but C-reactive protein was not significant. Conclusions: Stress rather than inflammation may affect plasma betaine concentrations.