海洋胶原肽抗皮肤老化作用的实验研究

目的 探讨海洋胶原肽抗皮肤衰老的作用及机制.方法 清洁级SD大鼠,每日腹腔注射D-半乳糖(0.125 g/kg)建立皮肤衰老模型,同时灌胃给予海洋胶原肽(0.225、0.450、1.350g/kg),连续进行90 d后,测定大鼠血清中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性及丙二醛(MDA)含量,并观察皮肤组织形态学改变.结果 海洋胶原肽干预后,动物皮肤表皮变厚,真皮层中成纤维细胞增多且活跃,3个海洋胶原肽干预组血清中抗氧化酶SOD的活性分别为(455.52±11.39)U/ml、(460.15±18.09)U/ml、(468.59±27.25)U/ml,明显高于模型对照组SOD的活性(395.56±15.25)U/ml;0.225 g/kg和1.35 g/kg海洋胶原肽干预后大鼠血清中CAT的活性分别为(21.33±4.82)U/ml和(21.69±1.68)U/ml,与模型对照组CAT活性(17.14±2.81)U/ml相比明显升高,0.450 g/kg和1.350 g/kg海洋胶原肽干预后大鼠血清中脂质过氧化产物MDA含量分别(5.67±0.93)nmol/ml、(5.76±1.02)nmol/ml,与模型对照组(7.63±1.37)nmol/ml相比显著性降低.结论 海洋胶原肽可通过提高机体抗氧化活性,从而有效延缓D-半乳糖所致的皮肤衰老.     

血清胱抑素C水平对新生儿窒息肾功能损伤的评价作用

目的 通过检测窒息新生儿血清胱抑素C(CysC)、血尿素氮(BUN)、血清肌酐(SCr)及计算内生肌酐清除率(Ccr),探讨血清CysC水平对评估窒息新生儿肾功能损伤的价值.方法 收集86例窒息新生儿(轻度窒息组46例,重度窒息组40例)及30例无窒息新生儿(对照组)的临床资料,于出生后24～72 h抽取股静脉血2ml测定血清CysC、BUN、SCr水平,通过计算Ccr来反映肾小球滤过率(GFR).结果 轻度窒息组血清CysC、BUN、SCr水平分别为(1.97±0.33)mg/L、(4.97±2.15)mmol/L、(90.41±24.32)μmol/L,重度窒息组分别为(2.65±0.41)mg/L、(10.88±3.31)mmoI/L、(125.82±45.44)μmol/L,对照组分别为(1.24±0.35)mg/L、(4.25±2.04)mmol/L、(58.41±19.22)μmol/L,三组各项指标比较差异均有统计学意义(P值均＜0.01),轻度窒息组与重度窒息组血清CysC、SCr水平均高于对照组;轻度窒息组CysC反映肾功能损伤的敏感性优于BUN、SCr;窒息新生儿CysC水平与GFR呈负相关(P＜0.01).结论 血清CysC可作为窒息新生儿肾功能损伤的指标,且敏感性优于BUN、SCr,CysC水平越高,窒息引起的肾损害程度可能越严重.     

燕麦β-葡聚糖对糖尿病大鼠肾病干预作用及机制

目的探讨燕麦β–葡聚糖对糖尿病大鼠肾病进展的干预作用及机制。方法采用链脲佐菌素(65 mg/kg)一次性腹腔注射+单侧肾切除的方式构建糖尿病肾病大鼠模型,造模成功后随机分为4组,分别为模型组(蒸馏水),和低、中、高剂量燕麦β–葡聚糖组(0.275、0.550、1.100 g/kg),每组12只;同时另取10只大鼠行假手术并灌胃蒸馏水,为对照组;干预8周。采集血液和尿液,检测尿素氮(BUN)、尿酸(UA)、血肌酐(CR)和血清炎症因子白细胞介素–6(IL-6)、血管内皮生长因子(VEGF)水平,并取肾脏做病理组织检测。结果与对照组比较,模型组大鼠血清尿素氮、VEGF、IL-6水平[分别为(14.80±3.63)mmol/L、(312.54±13.39)、(145.96±5.67)ng/L]明显升高(P0.05);与模型组比较,燕麦β–葡聚糖0.275 g/kg组大鼠血清尿素氮水平[(10.39±2.04)mmol/L]明显下降,燕麦β–葡聚糖0.550 g/kg组大鼠血清VEGF及IL-6水平[分别为(269.94±16.70)、(129.71±6.48)ng/L]明显下降,差异有统计学意义(P0.05);与模型组比较,燕麦β–葡聚糖组大鼠肾脏组织结构损伤明显减轻。结论燕麦β–葡聚糖可有效改善糖尿病肾病大鼠肾功能,延缓肾脏组织结构损伤,其机制可能与下调炎症相关因子表达水平,改善机体炎症状态有关。     

复方葛根素对糖尿病肾病Ⅳ型胶原的作用

目的 观察复方葛根素对糖尿病大鼠肾小球Ⅳ型胶原(IV-C)表达的影响.方法 利用链脲佐菌素腹腔注射法诱导建立1型糖尿病大鼠模型,将实验用SD大鼠按照数字表法随机分为正常对照组(10只)、糖尿病组(10只)、葛根素治疗组(10只)、维生素C治疗组(10只)、维生素C和葛根素联合治疗组(10只).治疗12周,观察治疗期间及治疗后大鼠的一般状况、血糖、尿素氮、血肌酐,内生肌酐清除率、糖化血红蛋白、血清Ⅳ-C、24 h尿蛋白排泄率,免疫组化检测肾组织Ⅳ-C蛋白表达,原位杂交检测肾组织Ⅳ-Cα1基因表达.结果 (1)4个糖尿病大鼠模型组大鼠均出现肾脏功能损害;(2)葛根素和维生素C能改善基本状况,降低糖尿病大鼠(葛根素治疗组、维生素C治疗组、联合治疗组)的尿素氮[(8.68±0.43)、(7.98±0.47)和(5.76±0.82)μmol/L]、血肌酐[(74.68±8.20)、(75.52±7.98)和(58.66±6.65)mmol/L]、24 h尿白蛋白排泄率[(18.40±0.37)、(17.24±0.30)和(9.97±1.27)mg/24 h×10-3];增加内生肌酐清除率[(0.59±0.21)、(0.61±0.14)和(0.69±0.32)ml/min];Ⅳ-C、[(111.56±14.61),吸光度显著下调(110.78±9.69)和(95.44±9.97)].结论 复方葛根素可能通过抑制Ⅳ-C的表达,具有确切的肾脏保护作用.     

枸杞多糖对大鼠肾缺血-再灌注后血清中TNF-α和IL-1β含量的影响

目的探讨缺血-再灌注对肾组织的损伤以及枸杞多糖(LBP)的治疗作用。方法实验大鼠被分成3组:LBP治疗组、假手术组和模型组,每组10只。LBP治疗组:大鼠在进行手术的前10天,每只大鼠按体重口服LBP,200 mg/kg,每天1次,以相同方式假手术组和模型组口服同等量的生理盐水。手术后48 h取大鼠肾组织,苏木素-伊红染色,显微镜下观察肾组织的结构;测各组大鼠尿量、血肌酐、尿素氮的含量的变化;酶联免疫检测大鼠血清中肿瘤坏死因子-α(TNF-α)及白介素-1β(IL-1β)的含量。结果在模型组的大鼠肾脏切片中观察到损伤及坏死,尿量[(4.35±0.51)ml]比假手术组明显减少,血浆中肌酐[(146.79±11.94)μmol/L]、尿素氮[(43.11±2.72)mmol/L]、TNF-α[(1 786.48±151.21)ng/L]及IL-1β[(1476.33±125.62)ng/L]水平比假手术组明显升高(P0.05);提前口服LBP后大鼠肾脏组织损伤及坏死减少,尿量(7.12±0.68 ml)比模型组明显增加,血浆中肌酐[(67.83±6.98)μmol/L]、尿素氮[(14.21±0.69)mmol/L]、TNF-α[(894.32±98.76)ng/L]及IL-1β[(623.58±72.45)ng/L]水平比模型组明显减少(P0.05)。结论缺血-再灌注会引起大鼠肾组织损伤,LBP治疗后会降低炎性因子TNF-α及IL-1β的含量来改善其损伤作用。     

海洋胶原肽的分子组成及其降血脂和抗氧化作用研究

目的 测定海洋胶原肽(marine collagen peptide,MCP)的相对分子质量,观察其对实验性高脂血症大鼠的血脂水平和抗氧化酶活性及脂质过氧化产物丙二醛(MDA)含量的影响.方法 采用葡聚糖凝胶层析、高效液相和基质辅助激光解吸电离飞行时间质谱方法对MCP组分进行分离和相对分子质量测定.选用50只健康雄性SD大鼠分成正常对照、高脂模型对照和1.0、3.0、9.0 g/kg MCP组,正常对照组大鼠喂饲普通饲料,高脂模型对照组和MCP组大鼠喂饲高脂饲料(79%基础饲料+10%猪油+10%蛋黄粉+1%胆固醇),MCP组大鼠以灌胃方式连续给予不同剂量的MCP(2 ml/100 g)45 d,测定血脂水平及血清谷胱甘肽过氧化物酶(GSH-Px)活力、超氧化物歧化酶(SOD)活性和MDA含量.结果 MCP的相对分子质量范围为100～860,摄人MCP 45 d后1.0、3.0和9.0 g/kg剂量组大鼠血清总胆固醇(TC)分别为(1.89±0.29)mmol/L、(2.07±0.39)mmol/L和(1.99±0.29)mmol/L,与高脂模型对照组(3.37±0.24)mmol/L相比明显降低;血清低密度脂蛋白胆固醇(LDL-C)水平分别为(0.83±0.16)mmol/L、(1.01±0.35)mmol/L和(0.91±0.26)mmol/L,明显低于高脂模型对照组(2.20±0.34)mmol/L;血清SOD活性分别为(218.6±33.2)U/ml、(242.7±21.4)U/ml和(242.1±44.8)U/ml,与高脂模型对照组(119.7±47.8)U/ml相比有显著升高;动脉粥样硬化指数(AI)分别为1.14±0.22、1.16±0.27和0.99±0.31,明显低于高脂模型对照组(2.27±0.55);抗动脉粥样硬化指数(AAI)分别为0.47±0.04、0.47±0.06和0.51±0.09,与高脂模型对照组(0.31±0.05)相比显著增高;3.0和9.0 g/kg剂量组大鼠血清甘油三酯(TG)水平分别为(0.90±0.15)和(0.86±0.12)mmol/L,明显低于高脂模型对照组(1.18±0.18)mmol/L;9.0g/kgbw MCP组大鼠血清MDA含量(7.1±4.1)nmol/ml明显低于高脂模型对照组(15.9±9.9)nmol/ml.结论 MCP具有降血脂和抗氧化的生物活性,对高脂血症的形成和动脉粥样硬化的发生具有一定的预防作用.     

左西孟旦治疗慢性重度心力衰竭合并肾功能失代偿期患者的疗效分析

目的 评价左西孟旦对慢性重度心力衰竭合并肾功能失代偿期患者的有效性和安全性.方法 选取慢性重度心力衰竭合并肾功能失代偿期患者105例,按随机数字表法分为对照组(53例)和左西孟旦组(52例),检测两组治疗前及治疗后1周血清N-末端脑钠肽前体、尿素氮、肌酐水平,同期应用心脏B超测定左心室射血分数(LVEF),并观察两组不良反应发生情况.结果 对照组不良反应发生率为16.98％(9/53),左西孟旦组为17.31％(9/52),两组比较差异无统计学意义(P＞0.05).左西孟旦组治疗后较治疗前血清N-末端脑钠肽前体、尿素氮、肌酐降低[(1764.19±25.21) ng/L比(7052.95±42.16) ng/L、(9.12±0.31) mmol/L比(16.91±2.98) mmol/L、(138.03±10.12)μmol/L比(222.68±16.16) μmol/L],LVEF升高[(45.08±7.07)％比(34.77±6.10)％],差异均有统计学意义(P＜0.05);对照组治疗后较治疗前血清N-末端脑钠肽前体降低[(2311.58±32.33) ng/L比(6887.56±48.23) ng/L],LVEF升高[(41.11±7.13)％比(36.89±5.05)％],差异均有统计学意义(P＜0.05),血清尿素氮、肌酐降低[(11.29±3.23) mmol/L比(14.84±2.86) mmol/L、(205.89±20.08) μmol/L比(217.51±12.22)μmol/L],但差异无统计学意义(P＞0.05);治疗后左西孟旦组较对照组血清N-末端脑钠肽前体、尿素氮、肌酐降低,差异均有统计学意义(P＜0.05),LVEF升高,但差异无统计学意义(P＞0.05).结论 左西孟旦对慢性重度心力衰竭合并肾功能失代偿期患者具有良好的有效性和安全性,同时还有明显的改善肾功能作用.     

包醛氧淀粉联合肾衰宁治疗慢性肾功能衰竭50例效果观察

目的探讨包醛氧淀粉联合肾衰宁治疗慢性肾功能衰竭的临床效果。方法选取2011年3月—2014年3月收治的慢性肾功能衰竭患者100例,随机分为治疗组和对照组各50例,对照组给予常规治疗,治疗组在常规治疗的基础上,给予包醛氧淀粉胶囊8粒/次,3次/d,肾衰宁胶囊4粒/次,3次/d。两组均治疗3个月。比较两组治疗有效率、血尿素氮、肌酐及肌酐清除率。计量资料采用t检验,计数资料采用χ2检验,P0.05为差异有统计学意义。结果治疗组总有效率92.0%,明显高于对照组的52.0%;两组患者治疗后血尿素氮为(13.6±12.24)mmol/L、肌酐为(310.35±110.15)μmol/L较治疗前的(23.5±12.35)mmol/L、(22.8±12.12)μmol/L均有明显降低,肌酐清除率为(29.84±3.58)ml/min较治疗前的(23.56±25.05)ml/min有明显升高,两组比较差异均有统计学意义(均P0.05)。结论包醛氧淀粉联合肾衰宁用于治疗慢性肾功能衰竭能够明显缓解患者的临床症状,临床效果确切,可以进行临床推广。     

海洋胶原肽对糖尿病大鼠脂代谢和抗氧化水平的影响

[目的]观察海洋胶原肽对四氧嘧啶诱导糖尿病大鼠血清脂质和抗氧化水平的影响。[方法]通过对SD大鼠腹腔注射四氧嘧啶建立糖尿病大鼠模型,随机分为海洋胶原肽低、中、高剂量组和高糖模型对照组,分别灌胃给予海洋胶原肽0.225g/kg.BW、0.450g/kg.BW、1.35g/kg.BW和同体积蒸馏水;另设定正常高剂量组和正常空白对照组,灌胃给予1.35g/kg.BW海洋胶原肽和同体积蒸馏水,连续8周。取大鼠尾血,测量血清脂质(TG、TC、LDL-C、HDL-C)和抗氧化指标(MDA、SOD)。[结果]试验开始时(0周)海洋胶原肽各剂量组大鼠TC、TG、MDA水平明显高于正常空白对照组,HDL-C、SOD水平则明显较低(P﹤0.05);与高糖模型对照组相比差异无统计学意义。干预8周后海洋胶原肽各剂量组血清TC水平仍高于正常空白对照组(P﹤0.05);而TG水平与正常对照组差异无统计学意义(P﹥0.05);4周末时低、高剂量组HDL-C明显上升,甚至高于正常空白对照组(P﹤0.05);LDL-C试验前后组间均无明显差异;各剂量组SOD活力仍明显低于正常空白对照组(P﹤0.05);MDA水平高于正常对照组,但低于高糖对照组(P﹤0.05)。[结论]海洋胶原肽可有效改善四氧嘧啶诱导糖尿病大鼠的脂代谢紊乱,并有一定的抗氧化损伤功能;由于糖尿病大鼠受损较严重,以上结论有待进一步研究证实。     

枸杞多糖对大鼠肾组织缺血-再灌注损伤的抗氧化保护作用

目的探讨缺血-再灌注对肾组织的损伤以及枸杞多糖(LBP)的干预作用。方法按照随机分组的方法将SD大鼠分为3组:假手术组、模型组和LBP干预组,每组10只。在大鼠制备模型的前1周,给予LBP干预组200 mg/kg灌胃,1天1次,假手术组和模型组给予相等体积的生理盐水灌胃。48 h后分别收集尿液,处死大鼠并取大鼠肾组织,苏木素-伊红染色,显微镜下观察肾组织的结构;测各组大鼠尿量、血肌酐、尿素氮含量的变化;测定肾组织中超氧化物歧化酶(SOD)及丙二醛(MDA)的含量。结果模型组大鼠肾组织中有大量的肾小管上皮细胞凋亡现象,血浆中肌酐[(144.81±13.98)μmol/L]和尿素氮[(42.45±2.67)mmol/L]的含量均明显增高,而尿量[(4.12±0.43)ml]明显减少,肾组织中SOD[(96.48±9.76)KU/g]活性降低,MDA[(267±13.21)μmol/g]含量升高,与模型组相比,其差异有统计学意义(P0.05);LBP干预组大鼠肾组织中肾小管上皮细胞凋亡数量减少,血浆中肌酐[(65.61±7.01)μmol/L]和尿素氮[(13.74±0.81)mmol/L]的含量均明显降低,而尿量[(6.84±0.71)ml]明显增加,肾组织中SOD[(263.34±10.26)KU/g]活性升高,MDA[(106.21±9.11)μmol/g)含量减少,与模型组相比,其差异有统计学意义(P0.05)。结论缺血-再灌注会引起大鼠肾组织损伤,LBP干预后会升高肾组织SOD活性,降低MDA的含量来改善其损伤作用。     

Effects of an immune-enhancing diet in endotoxemic rats

OBJECTIVE: This work compared the nutritional efficiency of a recently available enteral formula enriched with arginine, omega-3 fatty acids, and antioxidants and supplied nitrogen as peptides (Crucial, Nestle Clinical Nutrition) with that of a standard polymeric formula (Sondalis HP, Nestle Clinical Nutrition) in endotoxemic rats. METHODS: Male Wistar rats (209 +/- 2 g) underwent catheter gastrostomy and received Sondalis HP until they recovered their preoperative weight. At that time (day 0), an endotoxemic shock was induced by an intraperitoneal injection of lipopolysaccharide (Escherichia coli, 8 mg/kg) and rats then received 290 kcal x kg(-1) x d(-1) and 3.29 g of nitrogen x kg(-1) x d(-1) in the form of Crucial (IED group, n = 7) or Sondalis HP (S group, n = 6) for 3 d. Another group underwent no treatment and was fed ad libitum (AL group). Rats were killed on day 3. Results are presented as mean +/- standard error of the mean (analysis of variance and Newman-Keuls test). RESULTS: The endotoxemic shock induced a weight loss in group S on days 1 and 2 and a weight gain in group IED (-3.5 +/- 1.3 g in group S versus +6.0 +/- 2.2 g in group IED, P < 0.05). In the same way, atrophy of extensor digitorum longus muscle was observed in group S, whereas wasting was limited in group IED (102 +/- 4 mg in group IED versus 90 +/- 3 mg in group S versus 119 +/- 3 mg in group AL, P < 0.05). Muscular atrophy was associated with muscular glutamine depletion and correlated with hyperphenylalaninemia (R = 0.60), with the latter being blunted in group IED (57 +/- 1 microM/L in group AL versus 77 +/- 4 microM/L in group S versus 66 +/- 2 microM/L in group IED, P < 0.05). No difference was observed between the experimental groups of endotoxemic rats with respect to nitrogen balance, urinary excretion of 3-methyl histidine, or total tissue protein content. CONCLUSION: Crucial counteracts injury-mediated weight loss, extensor digitorum longus muscle atrophy, and hyperphenylalaninemia in endotoxemic rats.     

Aerobic exercise alters postprandial lipemia in African American versus White women

PURPOSE: To determine whether ethnicity influences postprandial lipemia after a bout of aerobic exercise. METHODS: Randomized crossover design. Healthy White (W; n=6) and African American (AA; n=6) women (age, W 27.0+/-3.3 yr, AA 21.6+/-1.4 yr; body-mass index, W 25.0+/-0.93 kg/m2, AA 25.8+/-0.79 kg/m2) participated in 2 treatments (control and exercise), each conducted over 2 d. On d 1, participants rested (control) or walked at 60% of maximal oxygen uptake for 90 min (exercise) and then consumed a meal. On d 2, after a 12-hr overnight fast, participants consumed an oral fat-tolerance test (OFTT) meal of 1.7 g fat, 1.65 g carbohydrate, and 0.25 g protein per kg fat-free mass. Blood was collected pre-meal and at 0.5, 1, 2, 3, 4, 5, and 6 hr post-OFTT and analyzed for triacylglycerol (TAG), glucose, and insulin. Areas under the curve (AUCs) were calculated for each blood variable. RESULTS: A significantly lower TAG AUC was observed for AA (0.86+/-0.24 mmol x L(-1) x 6 hr(-1)) after exercise than for W (2.25+/- .50 mmol x L(-1) x 6 hr(-1)). Insulin AUC was significantly higher for AA after exercise (366.2+/-19.9 mmol x L(-1) x 6 hr(-1)) than for the control (248.1+/-29.2 mmol x L(-1) x 6 hr(-1)). CONCLUSIONS: The data indicate that exercise performed approximately 13 hr before an OFTT significantly reduces postprandial lipemia in AA compared with W. It appears that AA women have an increased ability to dispose of TAG after exercise and a high-fat meal.     

The effects of creatine supplementation on cardiovascular, metabolic, and thermoregulatory responses during exercise in the heat in endurance-trained humans

The effects of creatine (Cr) supplementation on cardiovascular, metabolic, and thermoregulatory responses, and on the capacity of trained humans to perform prolonged exercise in the heat was examined. Endurance-trained males (n = 21) performed 2 constant-load exercise tests to exhaustion at 63 +/- 5 % VO(2max) in the heat (ambient temperature: 30.3 +/- 0.5 C) before and after 7 d of Cr (20 g x d (-1 ) Cr + 140 g x d (-1 ) glucose polymer) or placebo. Cr increased intracellular water and reduced thermoregulatory and cardiovascular responses (e.g., heart rate, rectal temperature, sweat rate) but did not significantly increase time to exhaustion (47.0 +/-4.7 min vs. 49.7 +/- 7.5 min, P =0.095). Time to exhaustion was increased significantly in subjects whose estimated intramuscular Cr levels were substantially increased ("responders" : 47.3 +/- 4.9 min vs. 51.7 +/- 7.4 min, P = 0.031). Cr-induced hyperhydration can result in a more efficient thermoregulatory response during prolonged exercise in the heat.     

Effect of Cr(VI) exposure on sperm quality: human and animal studies

The semen status of male workers occupationally exposed to hexavalent chromium(VI) was investigated. Sperm counts from exposed workers were 47.05+/-2.13 x 10(6)/ml and those from control group 88.96+/-3.40 x 10(6)/ml. Sperm motility decreased from 81.92+/-0.41% for the control group to 69.71+/-0.93% for the exposed workers. The levels of zinc, lactate dehydrogenase (LDH), and lactate dehydrogenase C4 isoenzyme (LDH-x) in seminal plasma for the exposed workers were 1.48+/-0.07 micromol/ml, 1.05+/-0.02 x 10(3) U, and 0.47+/-0.01 x 10(3) U, respectively, which were significantly lower than those of 5.72+/-0.15 micromol/ml, 1.49+/-0.02 x 10(3) U, and 0.78+/-0.15 x 10(3) U for the control group, respectively. Follicle stimulating hormone (FSH) (7.34+/-0.34 x 10(-3) IU/ml) in serum from the exposed workers was significantly higher than that (2.41+/-0.08 x 10(-3) IU/ml) from the control group. On the other hand, there were no significant differences in semen volume, semen liquefaction time, luteinizing hormone (LH) level in serum, and Cr concentration in both serum and seminal plasma between the exposed workers and the control group. Feeding Cr(VI) to rats significantly reduced the epididymal sperm counts from 87.40+/-3.85 x 10(6)/g epididymis in control group to 21.40+/-1.20 x 10(6)/g epididymis at a CrO(3) dose of 10 mg/kg body weight and to 17.48+/-1.04 x 10(6)/g epididymis at a CrO(3) dose of 20 mg/kg body weight. Exposure of rats to Cr(VI) also significantly increased the sperm abnormality from 2.75+/-0.06% in the control group to 6.68+/-0.32% in the exposed group at a CrO(3) dose of 10 mg/kg body and to 7.6+/-0.15% at a CrO(3) dose of 20 mg/kg body weight. In exposed rats, there was visible disruption in germ cell arrangement near the walls of the seminiferous tubules. The diameters of seminiferous tubules in exposed rats were smaller. These results suggest that occupational exposure to chromium(VI) leads to alteration of semen status and may affect the reproductive success of exposed workers.     

Protein pulse feeding improves protein retention in elderly women.

BACKGROUND: Adequate protein nutrition could be used to limit gradual body protein loss and improve protein anabolism in the elderly. OBJECTIVE: We tested the hypothesis that an uneven protein feeding pattern was more efficient in improving protein anabolism than was an even pattern. DESIGN: After a controlled period, 15 elderly women (mean age: 68 y) were fed for 14 d either a pulse diet (n = 7), providing 80% of the daily protein intake at 1200, or a spread diet (n = 8), in which the same daily protein intake was spread over 4 meals. Both diets provided 1.7 g protein x kg fat-free mass (FFM)(-1) x d(-1). Protein accretion and daily protein turnover were determined by using the nitrogen balance method and the end product method (ammonia and urea) after an oral dose of [15N]glycine. RESULTS: Nitrogen balance was more positive with the pulse than with the spread diet (54 +/- 7 compared with 27 +/- 6 mg N x kg FFM(-1) x d(-1); P < 0.05). Protein turnover rates were also higher with the pulse than with the spread diet (5.58 +/- 0.22 compared with 4.98 +/- 0.17 g protein x kg FFM(-1) x d(-1); P < 0.05), mainly because of higher protein synthesis in the pulse group (4.48 +/- 0.19 g protein x kg FFM(-1) x d(-1)) than in the spread group (3.75 +/- 0.19 g protein x kg FFM(-1) x d(-1)) (P < 0.05). CONCLUSION: A protein pulse-feeding pattern was more efficient than was a protein spread-feeding pattern in improving, after 14 d, whole-body protein retention in elderly women.     

A whey-supplemented, high-protein diet versus a high-carbohydrate diet: effects on endurance cycling performance

This study compared a training diet recommended for endurance athletes (H-CHO) with an isoenergetic high protein (whey supplemented), moderate carbohydrate (H-Pro) diet on endurance cycling performance. Over two separate 7-d periods subjects (n = 7) ingested either H-CHO (7.9 +/- 1.9 g x kg(-1) x d(-1) carbohydrate; 1.2 +/- 0.3 g x kg(-1) x d(-1) fat; 1.3 +/- 0.4 g x kg(-1) x d(-1) protein) or H-Pro (4.9 +/- 1.8 g x kg(-1) x d(-1); 1.3 +/- 0.3 g x kg(-1) x d(-1); 3.3 +/- 0.4 g x kg(-1) x d(-1)) diet in a randomized, balanced order. On day 8 subjects cycled (self-paced) for a body weight dependent (60 kJ/bm) amount of work. No differences occurred between energy intake (P = 0.422) or fat intake (P = 0.390) during the two dietary conditions. Performance was significantly (P = 0.010) impaired following H-Pro (153 +/- 36) compared with H-CHO (127 +/- 34 min). No differences between treatments were observed for physiological measures taken during the performance trials. These results indicate an ergolytic effect of a 7-d high protein diet on self-paced endurance cycling performance.     

儿童肾脏疾病患者血清胱抑素C的检测价值

目的 探讨儿童肾脏疾病患者不同时期血清中胱抑素C(CysC)的变化及其意义.方法 应用乳胶颗粒增强免疫比浊法测定182例患者(其中肾功能正常组73例、肾功能不全代偿组44例、肾功能不全失代偿组35例、肾衰竭组22例、肾终末组8例)和70例健康儿童(对照组)的血清CysC、肌酐(Cr)、内生肌酐清除率(Ccr)水平,比较CysC与Cr、Cer的相关性及受试者工作特征(ROC)曲线下面积.结果 血清CysC在肾功能损伤的不同时期均升高,且随着损伤程度的加重而明显升高,与Cr呈正相关,与Ccr呈负相关.CysC的ROC曲线下面积为0.764,Cr的ROC曲线下面积为0.725,CysC的ROC曲线下面积大于Cr的ROC曲线下面积.结论 CysC能准确地反映肾功能损害的严重程度及肾小球滤过功能,是肾功能损害早期的敏感指标,其灵敏度和特异度优于Cr、Ccr,对儿童肾脏疾病的早期诊断具有重要意义.     

Early curbing of protein hyper-catabolism in postoperative patients by nutritional support with glucose plus amino acids, but not with glucose alone

This work attempts to determine if there are differences in protein metabolism in post-surgical patients who receive parenteral nutrition with amino acids plus glucose (G+AA) or conventional gluco-salinal solution (GS). Eighteen patients submitted to gastrointestinal surgery were randomized and double-blindly administered either G+AA (1 g AA/kg x d and 28 kJ/kg x d), or GS (28 kJ/kg x d). Protein metabolism was determined 12 h after surgery (day 0) and after 5 days of nutritional support. On day 0, protein breakdown was similarly elevated, with respect to reference values, in both groups (GS: 4.62 +/- 0.25; G+AA: 5.25 +/- 0.50 g prot/kg x d) as a result of surgical stress. These values increased significantly at day 5 (P < 0.03) with the administration of GS to 6.93 +/- 1.00 g prot/kg x d, while they decreased (P < 0.002, 3.30 +/- 0.42 g prot/kg x d) with G+AA. Protein synthesis was increased (5.69 +/- 0.86 g prot/kg x d) with GS (P < 0.02), and was decreased (2.79 +/- 0.44 g prot/kg x d) with G+AA (P < 0.0002). Both synthesis and breakdown were inside normal reference values after 5 days for group G+AA. In both groups, nitrogen balance did not change significantly at day 5 compared to day 0. G+AA is effective in curbing the hypermetabolism produced by postoperative stress, achieving normal protein metabolism in 5 days, while GS increases the protein breakdown and synthesis. Nitrogen balance does not detect these modifications of the protein metabolism. Undernutrition on prognosis is not yet fully recognized.     

Normal value of resting energy expenditure in healthy neonates

OBJECTIVE: We investigated the value of resting energy expenditure (REE) in healthy neonates and evaluated the impact factors on REE. METHODS: One hundred eighty healthy neonates (95 boys and 85 girls) with birth weights above 2500 g were measured by indirect calorimetry, and the effect of birth weight evaluated. Measured and predicted REEs were compared, and the effects of sex and delivery method on REE were examined in 154 newborn infants with birth weights of approximately 2500 to 4000 g. RESULTS: Birth weight had a significant effect on REE. There was a negative relation between REE and birth weight (r = -0.289). The REEs of newborn infants weighing more than 4000 g were statistically lower than those of infants weighing 2500 to 4000 g (44.5 +/- 5.9 versus 48.3 +/- 6.1 kcal x kg(-1) x d(-1), P = 0.01). The measured and predicted REEs of 154 newborn infants were 48.3 +/- 6.1 and 54.1 +/- 1.1 kcal x kg(-1) x d(-1), respectively. There was a significant difference between the two values. Sex and delivery methods had no effect on REE in healthy neonates. CONCLUSIONS: The value from the predicted equation is not suitable for neonatal energy supplementation in clinical practice. The normal REE value for healthy neonates with birth weights of 2500 to 4000 g is 48.3 +/- 6.1 kcal x kg(-1) x d(-1).     

血清胱抑素C的检测在早期肾功能损害的应用评价

目的:评价血清胱抑素C(Cys-C)的检测在早期肾功能损害诊断中的临床应用。方法:按照肌酐清除率(Ccr)测量值大小将182例肾功能损害患者进行分组,选取67例健康体检者为对照组;酶法检测血肌酐(Scr)、血尿素氮(BUN)、Ccr,颗粒增强散射免疫法检测血清Cys-C的浓度,分析比较各组相关性。结果:各组血清Cys-C值比较差异有显著性(P0.05),且随着肾功能损害程度的增加,血清Cys-C值显著升高;中、重度肾功能损害及尿毒症组的Scr、Ccr和BUN与健康对照组差异有显著性(P0.05或P0.01)。结论:血清Cys-C是反映早期肾功能损害的灵敏诊断指标,可早期判断肾小球滤过功能损害。