The molecular nature of cholecystokinin in human plasma

Using a radioimmunoassay specific for the bioactive, tyrosine-sulfated sequence of cholecystokinin (CCK) we have studied the molecular nature of CCK in plasma from normal human subjects. CCK was extracted from postprandial plasma by Sep-Pak cartridges prior to Sephadex G-50 gel chromatography. Four CCK components eluting like CCK-58, CCK-33, CCK-22, and CCK-8, were identified in all samples. Of these, CCK-33- and CCK-8-like peptides predominated. The heterogeneity of circulating CCK emphasizes the importance of plasma assays that measure all bioactive forms of CCK.     

The nature of the immunoreactive lipotropins in human plasma and tissue extracts

This study was designed to establish definitively the nature of immunoreactive lipotropin (IR-LPH) in human plasma and tissue extracts. Using gel filtration, gel filtration under denaturing conditions, cationic exchange chromatography, immunoprecipitation, and radioimmunoassay, we have studied normal and tumorous human pituitaries, ectopic ACTH- and LPH-secreting tumors, plasma from normal subjects before and after dexamethasone administration, and plasma from patients with primary adrenal insufficiency and pituitary and nonpituitary ACTH- and LPH-secreting tumors. Except in the plasma and tumors of occasional patients with ectopic ACTH syndrome, the smallest IR-LPH appears to be λ-lipotropin (λLPH), which is often the predominant and occasionally the only IR-LPH present. The other major peptide appears to be βLPH, a 91-amino acid molecule that contains λLPH as its 1-58 sequence. Larger immunoreactive materials were observed in some specimens, but the “big” LPH in one plasma was shown to be λLPH bound to IgG.     

PDCA循环在人性化护理服务中的应用

在人性化护理服务中应用PDCA循环,使护理人员接受这一理念,主动地去经营这一服务,一切从病人的利益和感受出发,关注病人的生理、心理、社交及灵感性的各种需要,从而使护理服务卓有成效地运转起来。PDCA循环是科学的工作程序,PDCA循环应用于人性化护理服务中,有利于护理服务质量的提高,值得在临床护理服务中推广应用。     

神经外科护士实施人文关怀护理的临床效果研究

目的 探讨神经外科护士对颅脑损伤患者实施人文关怀护理的效果.方法 选取2009年3月～2009年12月间120例住院颅脑损伤患者,按时间段分为研究组和对照组,各60例,两组患者均同时给予常规药物治疗.对照组接受常规护理,研究组则制定人文关怀护理方案,实施人文关怀护理,于出院时,采用住院病人满意度调查表,症状自评量表(S...     

The nature of inactive renin in human plasma and amniotic fluid.

1. The properties of inactive and active renin in human plasma and amniotic fluid were studied chromatographically. Activation was achieved at pH 3.3 with and without added pepsin. 2. Acid activation of renin was time- and temperature-dependent but was inhibited by dilution of the sample. The dilution effect was corrected by adding pepsin. Such characteristics indicate that activation at low pH is catalysed by intrinsic enzymes. 3. Separation and/or dilution of the activating enzyme during ion-exchange chromatography concealed the eluted position of inactive renin and reduced the amount recovered. Only after full activation of the eluted renin was achieved with added pepsin was a distinct peak of inactive renin exposed. 4. At pH 7.5 inactive renin carried a lower negative charge than the active enzyme. This charge difference was lost after activation. 5. No molecular-weight differences between active, inactive renin or the International Renin Standard were detected by gel filtration. No renin of larger molecular weight was present. 6. These findings will be helpful in purification studies of human inactive renin.     

Norethynodrel metabolites in human plasma and urine

Norethynodrel metabolites in human plasma and urine were analyzed. Samples were collected from healthy young women over 1 24-hour period after the oral administration of 11.1 mg (50 mcCi) of 6, 7-tritiated norethynodrel. The 3 alpha-hydroxy compound from the reduction of the 3-ketone of norethynodrel was the major free metabolite in plasma, with lesser amounts of its 3 beta-isomer and norethindrone. These compounds were identified by carrier addition analysis and their concentrations were estimated by thin-layer radiochromatography. The bulk of plasma metabolites consisted of conjugates and greater than 95% of urinary metabolites (20% of total dose) were conjugated; 2 of which were beta-glucuronides. Enzymatic hydrolysis enabled the urinary compounds to be identified by gas-lizuid chromatography-mass spectrometry. 70-80% (10% of the dose) of the enzymatically hydrolyzed urinary metabolites were hydroxylated compounds. Triols were the principal hydroxylated compounds isolated. The metabolism of norethynodrel was rapid and extensive.     

Hydrophobic nature of rat lymph chylomicrons

BACKGROUND: A typical molecular structure of a lipoprotein is composed of hydrophobic lipids at the core and hydrophilic apolipoprotein side chains and lipid head groups at the surface. Some of the hydrophobic characteristics of rat lymph chylomicrons were investigated. METHODS: Thoracic duct was cannulated and lymph was collected overnight. Chylomicrons (>100 nm) were isolated by ultracentrifugation at 4 x 10(6)xg min. Since particle aggregation is a characteristic of hydrophobic nature of lipoproteins, as an index of aggregation, the turbidity generated by vortexing and storage of chylomicrons was measured spectrophotometrically at 680 nm. We also assessed the ability of chylomicrons to interact with five different hydrophobic interaction chromatography (HIC) media. RESULTS: Neither shaking nor prolonged storage at 4 degrees C produced an increase in the optical density of chylomicron solution indicating no aggregation took place. Typical elution profiles of chylomicrons through octyl, phenyl (high substance) and butyl sepharose columns showed two peaks. Peak I material emerged with 4 mol/l NaCl in a position corresponding to the void volume and peak II material eluted with water. Phenyl sepharose (high performance) media exhibited the maximum binding strength towards chylomicrons among the five different media. In the case of phenyl sepharose (low substance) column, an additional material was eluted with 3 mol/l NaCl between peaks I and II. These results indicate the heterogeneity of chylomicron surface hydrophobicity. CONCLUSION: Since particle aggregation is a characteristics of hydrophobicity of lipoproteins and believed to be an underlying cause of atherosclerosis, fractionation of lipoproteins by hydrophobic interaction chromatography may introduce a new approach into the assessment of lipoprotein atherogeneicity.     

Daunorubicin metabolites in human urine.

We studied the human metabolism of daunorubicin (D) by isolating and identifying metabolites from urine which retained the specific fluorescence properties of D. Metabolites were extracted by adsorption to polystyrene polymeric sorbants, separated on silicic acid columns and purified by thin-layer chromatography. Structures were determined by comparative chromatography, infrared, fluorescence and mass spectroscopy, and enzymatic and chemical degradation. D metabolites identified were daunorubicinol, daunorubicinol aglycone, deoxydaunorubicin aglycone, deoxydaunorubicinol aglycone, demethyl deoxydaunorubicinol aglycone, deoxydaunorubicinol aglycone 13-O-beta-glucuronide, demethyl deoxydaunorubicinol aglycone 4-O-sulfate and demethyl deoxydaunorubicinol aglycone 4-O-beta-glucuronide. Other metabolites have been purified but not identified. Human metabolism of D involves carbonyl reduction, reductive glycosidic cleavage, O-demethylation, O-sulfation and O-glucuronidation. Since daunorubicinol has biochemical properties similar to D, the metabolites may contribute to the pharmacologic and toxicologic effects credited to D.     

Competitive nature of the intestinal transport mechanism for cobalt and iron in the rat

Dose- and time-response studies were performed in iron-loaded and iron-deficient rats in order to define, (a) the kinetics of absorption of cobalt and iron, (b) the nature of the inhibitory effect of one metal on the absorption of the other, and (c) the effect of variations in body iron stores on these processes. The duodenum was perfused for 5-90 min with labeled solutions containing 5.0 mM iron or 5.0 mM cobalt. In iron-loaded rats, the rate of cobalt absorption was constant for 90 min whereas the rate of iron absorption fell after 30 min. In comparison to these results, the rate of absorption of both metals was increased in iron deficiency, and was more rapid in the first 30 min than in the 30-90 min period.To determine the response to varying doses of metal, we perfused duodenal loops for 30 min with 0.1-10.0 mM solutions of either iron or cobalt. In both iron-loaded and iron-deficient groups, a greater proportion of the metals was absorbed from smaller than from larger doses. When iron and cobalt were perfused together in iron-deficient animals, cobalt competitively inhibited iron absorption, and conversely, iron reduced cobalt absorption. The apparent maximum transport velocity was similar for both metals, but the affinity for cobalt was greater than iron.The results suggest that the absorption of cobalt and iron is mediated by a transport system in which two processes operate simultaneously; the first is limited largely by the concentration of available metal in the lumen of the intestine, whereas the second process depends upon the activity of a mechanism which displays saturation kinetics and competitive inhibition. The former process prevails when iron stores are replete, whereas the latter predominates when there is a need for iron, such as in iron deficiency.     

The estimation of vitamin D and some metabolites in human plasma by mass fragmentography

A mass fragmentographic assay for vitamin D3, 25-hydroxyvitamin D3, 25-hydroxyvitamin D2 and 24,25-dihydroxyvitamin D3 is described. After extraction of plasma with methanol and dichloromethane, Lipidex 5000 chromatography was used to separate the plasma extract into three fractions (a vitamin D fraction, a 25-hydroxyvitamin D fraction and a 24,25-dihydroxyvitamin D fraction). Cholesterol was removed from the vitamin D fractio by thin-layer chromatography. :After addition of vitamin D2 to each fraction, isotachysterol trimethylsilyl ethers were formed. Recoveries prior to gas chromatography-mass spectrometry were assessed by the use of tritiated standards added to the plasma before extraction. Using this procedure, normal ranges were established (vitamin D3: 3--17.7, 25-hydroxyvitamin D3: 5.9--35.2, 25-hydroxyvitamin D2: 0.6---1.0 and 24,25-dihydroxyvitamin D3: 0.6--2.9 micrograms/l).