纤维素酶法提取茶多糖

为了保持茶多糖的活性 ,采用低温水提、酶提二次结合法提取茶多糖 .第一次在 5 0℃、茶叶与水的质量比为 1∶1 5、水提取 3 0min ,多糖的提取率为 2 .3 3 % ,粗多糖 (干重 )的提取率为6.82 % ;过滤后 ,滤渣用 pH 4.6的柠檬酸 柠檬酸钠缓冲液加纤维素酶提取 ,经正交试验确定酶提最佳工艺参数为 5 5℃、茶叶与水的质量比为 1∶1 4、酶用量 2 .2 μL/g(以茶叶质量计 ) ,反应时间为1 2 0min ,其多糖的提取率为 0 .64% ,粗多糖 (干重 )的提取率为 1 .1 1 % ,分别占二次总提取量的2 1 .5 %和 1 4.0 % ,而在相同条件下无酶提取 ,提取率仅为 0 .3 9%和 0 .5 6% .相对水提法 ,酶法的多糖提取率分别增加 63 .3 %和 98.9% ,多糖总提取率达 2 .97% ,粗多糖 (干重 )的总提取率为7.93 % .采用酶法提取的茶多糖具有较强抑制α 淀粉酶活力的能力 .     

雪莲水溶性多糖提取工艺的研究

雪莲多糖是一种水溶性的功能性天然多糖,作者比较了料液比、温度、提取时间等因素对新疆雪莲组织培养物中雪莲多糖提取率的影响。结果表明,雪莲水溶性多糖的最佳提取工艺条件为料液比为1 g∶12 mL,温度85℃,时间2 h.粗多糖最大得率为7.08%。此粗多糖总糖质量分数为15.37%,从糖含量的角度,新疆雪莲组织培养物提取的粗多糖是野生雪莲提取的粗多糖的优良替代物品。     

超声波辅助提取苹果渣多酚工艺

研究了超声波辅助提取苹果渣中多酚的工艺,利用二次回归正交旋转组合设计考察了乙醇体积分数、料液质量体积比、提取温度、提取时间对苹果渣中多酚物质提取率的影响;试验结果表明,各因子对提取率的影响大小依次是提取温度＞料液质量体积比＞提取时间＞乙醇体积分数;最佳提取工艺条件是:乙醇体积分数50%、料液比1 g:20 mL、提取温度60℃、提取时间24min;此条件下苹果多酚的提取率为3.80 mg/g.     

壳聚糖的溶解性能及体内生物相容性评价

目的：观察酸溶性壳聚糖在醋酸溶液中的溶解相关性指标,并对水溶性及酸溶性两种壳聚糖的体内相容性和降解性进行评价,为壳聚糖组织工程支架的制备和应用提供参考。方法：用1%的醋酸溶液配制质量浓度为1%、2%、3%、4%的酸溶性壳聚糖溶液,利用黏度分析仪器和pH计测定其黏度和pH值;将2%的酸溶性壳聚糖溶液溶解在不同体积分数（1%、1.5%、2%、2.5%、3%）的醋酸溶液中,检测其黏度和pH值的变化。在BALB/c小鼠腿部肌肉内植入酸溶性壳聚糖或水溶性壳聚糖0.1 g,比较组织相容性和体内降解时间。结果：酸溶性壳聚糖溶液的黏度、pH值随壳聚糖质量浓度的增加而增加。等量的壳聚糖溶解在不同酸度的醋酸中,其黏度和pH值均随酸度的增加而降低。水溶性壳聚糖生物相容性要优于酸溶性壳聚糖,水溶性壳聚糖降解时间〈7 d,酸溶性壳聚糖降解时间〉21 d。结论：壳聚糖在醋酸溶液中的溶解性能与溶液的酸度有关,溶液的黏度和pH值与壳聚糖质量浓度和酸浓度两个因素均密切相关。水溶性壳聚糖的体内相容性及降解性明显优于酸溶性壳聚糖。     

微波辅助提取玉米须多糖及其组成的研究

采用料液质量比、微波功率、微波时间、水浴浸提温度、水浴浸提时间的单因素试验和正交试验来优化微波提取玉米须中水溶性多糖(CSPS)的条件.试验表明,前4种因素对多糖提取率的影响较大.微波辅助提取玉米须水溶性多糖的最佳工艺参数为:料液质量比为1 g∶50 g,在微波功率为560 W(最大700 W)的条件下提取3 min,再经100℃水浴浸提30 min.与未经微波辐照的提取方法相比较,微波辅助提取的方法时间短、产率高(最高可达2.43倍),是玉米须水溶性多糖提取的一种优选方法.然后,玉米须多糖用硫酸水解得到单糖,衍生后经GC检测,初步鉴定玉米须多糖是由葡萄糖、木糖及鼠李糖3种单糖组成.     

牛蒡菊糖的提取及其分离纯化

以水提醇沉工艺,采用单因素实验和正交实验设计方法研究料液比、提取温度、提取时间以及提取次数对牛蒡菊糖提取率的影响,得到牛蒡菊糖提取的最佳因素组合：料液比1∶15（g∶mL）,提取温度80℃,提取时间90 min,提取2次,提取率为90.86%。比较不同的脱色、脱蛋白方法,得到纯度较高的均一多糖。     

谷氨酸菌体中核酸类物质的提取

研究了谷氨酸菌体中核酸提取的工艺条件 ,获得了较好效果 .在 12 0℃ ,pH 9,菌体质量浓度 10 g/dL的条件下 ,提取 2h ,蛋白质的分离率为 90 % ,核酸的提取率高达 90 %以上 .     

微波提取青钱柳多糖的研究

使用微波辅助提取技术,通过单因素实验和L9（3^4）正交试验对多糖提取工艺进行了优化,并与常规热水提取法进行比较。结果表明：以水为溶剂,青钱柳多糖提取的最佳工艺为：提取功率为1400 W,提取时间为30 min,料液比质量体积1 g∶20 mL,提取得率为2.55%,;与常规提取法相比,微波辅助提取法具有提取时间短、提取率高等优点。     

山药粗多糖的提取工艺

对鲜山药中水溶性粗多糖的提取工艺进行了研究,通过单因素试验和L9（34）正交试验,研究了料液比、提取温度、时间和乙醇体积分数对粗多糖得率的影响,极差分析及方差分析结果表明提取温度和料液比是影响山药粗多糖提取的主要因素,较优的工艺为料液比1 g：9 mL,温度50 ℃,时间2.5 h,乙醇体积分数75%,在此工艺条件下,鲜山药粗多糖得率为0.2449%（以鲜山药质量计）.     

二氢杨梅素的超声波辅助溶剂提取工艺

对显齿蛇葡萄中二氢杨梅素的超声辅助溶剂提取工艺进行了研究,在单因素实验和正交实验的基础上,得出超声波法辅助溶剂提取显齿蛇葡萄中二氢杨梅素的最佳工艺条件为：在40℃下,以液料体积质量比为15 mL∶1 g的体积分数65%乙醇溶液,超声波辅助溶剂提取40 min,目标物二氢杨梅素的一次提取率可达93.1%,优于常规的热提取法。     

酒石酸钾预防草酸钙肾结石形成的研究

体外实验证明酒石酸钾对一水草酸钙晶体的生长和聚集有抑制作用。动物实验发现酒石酸钾能够降低鼠肾组织中钙及草酸的沉积。２７例患者口服酒石酸钾期间，２４小时尿钙、磷和草酸明显下降，尿枸橼酸和尿ＰＨ显著上升，实验证明，酒石酸钾能够抑制草酸钙肾结石的形成，是一种有希望的防石药物。     

Nutritional intervention high in vitamins, protein, amino acids, and omega3 fatty acids improves protein metabolism during the hypermetabolic state after thermal injury.

HYPOTHESIS: Characteristic of the hypermetabolic response to a thermal injury is the massive protein catabolism and compromised structure and function of essential organs. Nutrition has been suggested to affect protein metabolism and clinical outcome after a severe injury but published studies show controversial data. The purpose of this study was to determine the effect of enriched nutritional support during the postburn hypermetabolic state on protein metabolism in serum, liver, muscle, and skin. SETTING: Laboratory. INTERVENTION: Twenty-two rats were given burns covering 60% of their total body surface area and randomized to receive either standard rat chow (control) or a diet high in vitamins, protein, amino acids, and omega3 fatty acids. MAIN OUTCOME MEASURES: Five weeks after injury, body weight, serum, muscle, and hepatic protein content, insulin-like growth factor I concentration, and wound healing (reepithelization) were determined. RESULTS: Rats receiving the enriched diet showed a gradual improvement in body weight 1, 2, 3, 4, and 5 weeks postburn compared with controls (P< .001). Diet-fed rats demonstrated higher protein and insulin-like growth factor 1 content in serum, muscle, and liver 5 weeks after trauma (P< .001). Serum protein, albumin, and transferrin levels were significantly increased in rats receiving the diet compared with control rats (P< .001). Reepithelization was accelerated in rats receiving the enriched diet 4 (diet-fed, mean +/- SD, 23% +/- 1% vs controls, 17% +/- 1%; P< .001) and 5 (diet-fed, 24% +/- 1% vs controls, 18% +/- 1%; P< .001) weeks postburn compared with control rats. CONCLUSIONS: Nutritional intervention high in protein, vitamins, amino acids, and omega3 fatty acids improves protein net balance during the hypermetabolic response to thermal injury. Compromised organ function and structure and clinical outcome during the hypermetabolic response may be improved.     

Effects of an amino acid dialysate on leucine metabolism in continuous ambulatory peritoneal dialysis patients

BACKGROUND: Protein-energy malnutrition is frequent in continuous ambulatory peritoneal dialysis (CAPD) patients. The use of amino acids in the dialysate could improve the protein balance, especially if associated to a concomitant energy intake. METHODS: A 1.1% amino acid solution for peritoneal dialysis was administered to CAPD patients over 30 minutes during concomitant absorption of 600 ml water (control study) or of a 600 kcal meal/600 ml. Leucine metabolism was studied using the combination of intravenous [2H3] and intraperitoneal [13C] leucine. RESULTS: The rate of leucine appearance was stimulated by 56 and 53% (control and meal) at 45 minutes. The rates of leucine appearance and disappearance were lower from 180 to 300 minutes during the meal versus control study (P < 0.05). Proteolysis was unaffected during the control study and was inhibited by 25% during the meal study (P < 0.05). During the five-hour cycle dialysis with or without a meal, 80% of the leucine administered into the peritoneum was absorbed. Forty-one percent was retained in the splanchnic bed. Forty-three percent was used for protein synthesis, and 16% was oxidized. CONCLUSIONS: This amino acids solution is efficaciously utilized for protein synthesis in CAPD patients with no effect on protein breakdown. The concomitant ingestion of a carbohydrate-lipid meal inhibits protein breakdown and reinforces a positive effect of the amino acids solution on protein balance.     

Urodynamic studies on hemiplegic patients after cerebrovascular accident

Thirty-nine hemiplegic patients were evaluated by complete urodynamic study after cerebrovascular accidents. Computerized tomography was performed to identify localization of the brain lesion. The common urinary symptoms were frequency and urgency incontinence (26/39), while 13 patients complained of dysuria or urinary retention. Tell of the 11 patients who had frontal and internal capsular lesions showed hyperactive bladder, and 6 showed uninhibited sphincter relaxation. Nine of the 10 patients who had putaminal lesions showed hyperactive bladder. Normal sphincter activity was demonstrated in 7 of these 10 patients. In the remaining patients with the other types of lesions, no correlation was found between urodynamic dysfunction and type of brain injury.     

Whole-body nitrogen and tyrosine metabolism in surgical patients receiving branched-chain amino acid solutions

Fifteen patients undergoing gastric bypass surgery for morbid obesity received preoperatively a standard crystalline amino acid solution containing 15.6% branched-chain amino acids. During the first five postoperative days, the patients were randomized to receive one of three amino acid solutions (9.0 to 10.3 g of nitrogen per day) of different branched-chain amino acid content. The branched-chain amino acid concentrations of the mixtures were 15.6%, 50%, and 100% by weight with five patients in each group. Whole-body amino acid appearance and oxidation were estimated using a continuous intravenous infusion of L-(U-14C)-tyrosine preoperatively and on the third postoperative day. Daily postoperative nitrogen balance, fractional albumin renewal rate, and whole-body tyrosine appearance, oxidation, and incorporation into protein were not significantly different among the three groups. This study suggests that an adequate nitrogen intake of a balanced amino acid mixture, as well as a solution enriched with branched-chain amino acids, maintains protein homeostasis and supports protein synthesis similarly in well-nourished patients following major abdominal surgery. A diet containing only branched-chain amino acids in isomolar ratios was as effective at maintaining protein retention and whole-body protein synthesis and albumin renewal postoperatively when compared with a standard amino acid formula.     

Branched chain amino acid administration and metabolism during starvation, injury, and infection.

Branched chain amino acids were administered intragastrically in a septic-fractured rat model to determine the degree and mechanism of their protein-sparing ability. The septic injury model was first shown to produce a metabolic response characterized by hyperglycemia, reduced ketonemia and increased nitrogen loss. Branched chain amino acids were then administered either alone or as 25% or 50% (w/w) of a complete crystalline amino acid solution. L-(U-14C)-tyrosine was added to the diet to estimate protein synthesis in individual tissues. Branched chain amino acids, when given alone, spared total body nitrogen as compared with fasting by increasing the fractional synthesis of both mixed liver and muscle protein. Although the two complete amino acid mixtures produced similar nitrogen preservation and muscle synthesis in the septic animals, the crystalline amino acid diet containing 50% branched chain amino acids resulted in the greatest preservation of total liver nitrogen and the highest fractional synthetic rate. The effect of branched chain amino acids would not appear to be explained by their nitrogen content alone, and in starvation with injury and infection, increased intakes may have potential benefit. Clinical trials in starved, injured man appear to be indicated.     

Amino acids stimulate leg muscle protein synthesis in peripheral arterial disease

OBJECTIVE: Older patients with peripheral arterial disease (PAD) and intermittent claudication have impaired walking ability resulting from reduced lower extremity blood flow. Evidence suggests that leg muscle abnormalities may also contribute to walking intolerance in claudicants. In healthy elderly people, leg muscle protein synthesis can be augmented by nutritional supplementation with amino acids; preliminary data suggest that this increases muscle mass, walking ability, and functional status. In this study, we investigated whether amino acid supplementation would improve leg muscle protein synthesis in elderly PAD subjects, given that reduced leg blood flow might restrict the availability of amino acids to muscle. METHODS: Two groups participated in the study: a group of 11 claudicants (mean age, 62 years; mean ankle-brachial index, 0.62; 46% male) and a group of 9 age- and sex-matched healthy controls (mean ankle-brachial index, 1.1). Both groups underwent measurement of leg blood flow by using strain gauge plethysmography, as well as measurement of baseline and amino acid-stimulated protein synthesis in leg muscle. Protein synthesis was quantified from calf muscle biopsy samples by measurement of the fractional synthetic rate (FSR) of protein, by using the incorporation of the stable isotope l-[ring-(2)H(5)]-phenylalanine into muscle protein. Total protein was extracted from muscle samples, and gas chromatography/mass spectroscopy methodology was used to measure incorporation rates. After measurement of basal FSR, all subjects were given an oral drink of 15 g of essential amino acids, and the measurements of FSR were repeated. Data are expressed as mean +/- SD; statistical analysis of differences between the two groups (with and without amino acid supplementation) was performed by using analysis of variance with repeated measures. RESULTS: Calf blood flow was reduced in the PAD subjects compared with controls (1.44 +/- 0.53 mL/min per 100 mg of tissue vs 2.40 +/- 0.57 mL/min per 100 mg of tissue; P = .005; t test). FSR in the basal state was equivalent between the two groups (healthy, 0.060% +/- 0.025% per hour; PAD, 0.061% +/- 0.029% per hour; P = .97). Equivalent increases (P < .05) occurred in both groups in response to oral amino acid supplementation (healthy, 0.087% +/- 0.012% per hour; PAD, 0.104% +/- 0.041% per hour; P > .05; analysis of variance). CONCLUSIONS: Despite reduced leg blood flow, elderly PAD patients synthesize calf muscle protein in the basal state in a fashion similar to that in healthy elderly people. More importantly, administration of exogenous amino acids produces a significant increase in protein synthesis in these patients that is also equivalent to that in healthy elderly people. Our goal is to use these results as the basis for an intervention study to determine whether long-term oral amino acids, by augmenting calf muscle protein synthesis, increase calf muscle mass, walking ability, and functional status in elderly claudicants.     

The use of an amino-acid-based CAPD fluid over 12 weeks

Eight patients with end-stage renal failure (plasma albumin less than 35 g/l) who were established on glucose CAPD exchanges, were studied for 4-week periods before, and after 12 weeks when 1% amino-acid solution had been used for the morning exchange. Anthropometric, biochemical, clinical and dietary assessments were made every 4 weeks. Dietary intakes of protein and calories were maintained. Studies with amino-acid solutions showed a mean of 13% and 8% amino acids remaining in the dialysate after 6 and 8 h respectively. Plasma amino acids increased to a maximum after 2 h of dialysis; however, fasting concentrations were constant over the 5 months. Osmolality of amino acids decreased comparably with 1.36% glucose during 8-h exchanges although the recovery of fluid was marginally less. Plasma transferrin increased significantly after 8 weeks of amino acids but subsequently decreased in one patient due to infection. No significant changes occurred in albumin, apolipoprotein A, IgG, IgA or prealbumin. Cholesterol and apolipoprotein B decreased in seven patients but increased in one due to rising calorie intake. Increases in urea and decreases in bicarbonate were not clinically significant. Amino-acid-based fluid was well tolerated with modest nutritional benefit and reduction in hyperlipidaemia. Optimal effects of amino acids are likely at higher concentrations using two or more exchanges in patients eating less than 0.9 g protein/kg per day.     

Isolation and characterization of a cDNA for osteopontin-k: a kidney cell adhesion molecule with high homology to osteopontins.

Screening of a bovine renal cDNA library with MAbs resulted in the isolation of a 1447 bp cDNA. This cDNA (pBk2.1) was sequenced and shown to contain an open reading frame with a putative protein of 261 amino acids, with a molecular weight of 29,573 (minute leader sequence) and a hydrophobic leader sequence of 16 amino acids. pBk2.1 was shown to share a high level of nucleic acid sequence homology over portions of its sequence to human, porcine, mouse, and rat osteopontins (40-60%). The peptide (osteopontin-k) had a potential glycosylation site (Asn-X-Ser/Thr), a GRGDS receptor binding region, a high level of asparagine residues, and a high abundance of acid amino acids characteristic of osteopontin-like cell adhesion molecules. The N-terminal amino acid region of pBk2.1 (the first 82 amino acids) and 42 amino acids at the C terminus had the highest level of homology with the osteopontins at 86%. The middle portion of the peptide had greatly reduced homology, ranging from 50% (amino acids 83-174) to 12% (amino acids 175-219). There were also deletions and additions of sequence in osteopontin-k that were not found in the other osteopontins. The homologies suggest that these proteins are highly related and may be derived from a common gene by alternative splicing. A 678 bp cRNA probe constructed from pBk2.1, containing a region with low homology to the osteopontins (amino acids 183-219 with less than 20% homology, plus amino acids 220-261 and untranslated sequence), was used in northern blots and RNAse protection assays.(ABSTRACT TRUNCATED AT 250 WORDS)     

Oral essential amino acid supplementation in patients on maintenance hemodialysis

Sixteen patients with chronic renal failure on maintenance hemodialysis were studied before and during oral treatment with essential amino acids. The patients received their usual diets (60-100 g protein/day) throughout the study. Plasma amino acids were studied pre-dialysis before supplements were started, after one month and after three months treatment; some measurements were also carried out post-dialysis. Before treatment 63% of patients pre-dialysis, and 82% post dialysis, had at least one essential amino acid value which was lower than our normal range. After one month of treatment 38% of patients pre-dialysis, and 67% post-dialysis, had one or more low essential amino acid value. After 3 months only 2 patients had an abnormal essential amino acid chromatogram pre-dialysis. Changes in non-essential amino acids, blood urea, serum proteins and hemoglobin are also reported. The data show that low plasma essential amino acid concentrations are frequently present in patients on maintenance hemodialysis even when the diet contains theoretically adequate amounts of protein. This deficiency can be corrected successfully with oral essential amino acid supplements.