Sensitized chemiluminescence determination of fluorouracil in pharmaceutical and biological fluids based on potassium permanganate oxidation in the presence of formaldehyde

A novel chemiluminescence (CL) reaction system was established for the anticancer drug fluorouracil (5-FU). We developed a formaldehyde-sensitized CL emission mechanism for 5-FU-KMnO(4)-HCl systems by comparing the fluorescence emission with CL spectra. The illuminant was the singlet-state bimolecular oxygen (1)O(2) (1)O(2)((1)Delta(g) (1)Delta(g)), which is from (1)O(2)((1)Delta(g)) produced in the reaction system, and emits CL spectra at 639 nm. The presence of formaldehyde can sensitize CL emission by accelerating the generation of (1)O(2)((1)Delta(g)). The optimum conditions for CL emission were investigated. The relationship between the relative CL intensity and the concentration of the analyte showed good linearity. The determination limit was 3 x 10(-8) g mL(-1). The relative standard deviation (SD) was 1.8%. The proposed method was applied to the determination of fluorouracil in pharmaceutical preparations and biological fluids, and satisfactory results were obtained.     

Hydroxyl radical-induced characteristic chemiluminescent spectra from plasma of hemodialysis patients.

Plasma from hemodialysis patients evoked weak photon emissions (chemiluminescence) in a characteristic emission spectrum with a peak at 430 nm, attributed to attack by hydroxyl radicals generated from the iron-catalyzed breakdown of hydrogen peroxide (Fenton reaction), whereas plasma from normal healthy subjects showed a rather weak red chemiluminescence peak at around 680 nm, similar to that resulting from attack by hydroxyl radicals. However, the addition of hydrogen peroxide in the absence of divalent irons induced almost the same red chemiluminescent emission spectrum in both plasmas. The HPLC-gel-filtration chromatography carried out with both plasmas revealed that a primary emitter evoking a peak emission at 430 nm was located in the fraction of lower-molecular-mass substances in fractionated plasma from hemodialysis patients. In contrast, the elution peaks evoking red chemiluminescence with the addition of hydrogen peroxide were mainly observed for the higher-molecular-mass fraction, as determined by gel chromatography of both plasmas. Therefore, the observation of a chemiluminescence peak at 430 nm, induced by the generation of hydroxyl radicals, correlated well with chemiluminescent emissions in plasma samples from patients with chronic renal failure. Spectral analyses of clinical samples that show weak chemiluminescence by forced oxidation by such an active oxygen may provide a new and more sensitive method for diagnosing metabolic disorders.     

Determination of hydroxycamptothecinum by flow injection analysis with chemiluminescence detection

An novel analytical method consisting of flow-injection sampling and chemiluminescence (CL) detection for determination of anticancer drug hydroxycamptothecinum (HCPT) is described. It is based on the CL reaction of potassium permanganate-formaldehyde-HCPT system. The formaldehyde-sensitized CL emission mechanism was proposed for HCPT-potassium permanganate (KMnO(4))-HCOH systems by comparing the fluorescence emission with CL spectra. Illuminant was the single-state bimolecular oxygen, (1)O(2) (1)O(2)((1)Delta(g) (1)Delta(g)), which was from (1)O(2)((1)Delta(g)) produced in the reaction system, and emits CL spectra at 639 nm. The presence of formaldehyde can sensitized CL emission, because it may be to accelerate the generation of (1)O(2) ((1)Delta(g)). The optimum conditions for CL emission were investigated and optimized. The CL intensity was correlated linearly with concentration of HCPT in the range of 0.010-60.0 mg L(-1). The determination limit is 0.006 mg L(-1). The relative standard deviation is 1.6% for 11 parallel measurements of 0.20 mg L(-1) HCPT standard solution. The proposed method has been applied for the determination of HCPT in pharmaceutical preparations, serum, and urine. The results of the quantitative analysis for HCPT studied using the developed method showed a good agreement with provided by using an official method.     

The substrate activity of (S)-9-[3-hydroxy-(2-phosphonomethoxy)propyl]adenine diphosphate toward DNA polymerases alpha, delta and epsilon

In this study, we examined the substrate potency of (S)-9-[3-hydroxy-(2-phosphonomethoxy)propyl]- adenine diphosphate (HPMPApp) toward DNA polymerases alpha, delta and epsilon. The efficiency of HPMPApp incorporation decreased in the order pol epsilon >pol delta =pol alpha and was from 5.4- to 23-fold lower than that of dATP. Depending on which template-primer was used, the HPMPAppKm value was 3.3- and 8.3- (pol alpha), 3- and 0.82- (pol delta) or 2-fold (pol epsilon) higher than dATPKm. The ability of HPMPA to accumulate in DNA decreased in the order pol epsilon >pol alpha >pol delta. The difference between the elongation rate of DNA with and without one HPMPA molecule at 3' termini was about 1.1-2.3 fold. The 3'-5'-exonuclease activity of pol delta and epsilon can excise HPMPA from DNA. These observations indicate that interaction of HPMPApp with pol alpha, delta and epsilon may contribute to its cellular toxicity and explain its antiviral activity against polyomavirus.     

Influence of the physical and chemical properties of magnetic nanoparticles on their performance in a chemiluminescence immunoassay

Objectives

Magnetic nanoparticles (MNPs) are important carriers in immunoassays. In this study, we investigated the influence of the physical and chemical properties of MNPs on their performance in a detection process.

Design and methods

A comparative study of the properties of two MNPs with sizes of 200 nm and 1 μm (MNP-200 nm and MNP-1 μm, respectively) was conducted using the following four aspects: nonspecific adsorption to proteins (IgG was used as a model protein), influence of magnetic nanoparticles on the chemiluminescence signal, response speed to an external magnetic field, and intensity of the detection signal.

Results

MNP-1 μm exhibited lower nonspecific adsorption to IgG in serum, a weaker interference with the chemiluminescence signal, and a higher response speed to the external magnetic field than the same amount of MNP-200 nm. An automated chemiluminescence immunoassay system based on MNP-1 μm was also established.

Conclusions

MNP-1 μm acts as an excellent carrier in an automated chemiluminescence immunoassay system for the analysis of serum samples from clinical patients.     

Mannopeptimycins,new cyclic glycopeptide antibiotics produced by Streptomyces hygroscopicus LL-AC98: antibacterial and mechanistic activities

Mannopeptimycins alpha, beta, gamma, delta, and epsilon are new cyclic glycopeptide antibiotics produced by Streptomyces hygroscopicus LL-AC98. Mannopeptimycins gamma, delta, and epsilon, which have an isovaleryl substitution at various positions on the terminal mannose of the disaccharide moiety, demonstrated moderate to good antibacterial activities. Mannopeptimycin epsilon was the most active component against methicillin-resistant staphylococci and vancomycin-resistant enterococci (MICs, 2 to 4 micro g/ml for staphylococci and streptococci and 4 to 32 micro g/ml for enterococci), while mannopeptimycins gamma and delta were two- to fourfold less active. Mannopeptimycins alpha and beta, which lack the isovaleryl substitution and the disaccharide moiety, respectively, had poor antibacterial activities. The in vivo efficacies of the mannopeptimycins in Staphylococcus aureus mouse protection studies paralleled their in vitro activities. The median effective doses of mannopeptimycins gamma, delta, and epsilon were 3.8, 2.6, and 0.59 mg/kg of body weight, respectively. The mannopeptimycins were inactive against cell wall-deficient S. aureus and caused spheroplasting of Escherichia coli imp similar to that observed with penicillin G in an osmotically protective medium. Mannopeptimycin delta rapidly inhibited [(3)H]N-acetylglucosamine incorporation into peptidoglycan in Bacillus subtilis and had no effect on DNA, RNA, or protein biosynthesis. On the basis of the observations presented above, an effect on cell wall biosynthesis was suggested as the primary mode of action for mannopeptimycin delta. The mannopeptimycins were inactive against Candida albicans, did not initiate hemolysis of human erythrocytes, and did not promote potassium ion leakage from E. coli imp, suggesting a lack of membrane damage to prokaryotic or eukaryotic cells.     

The CD3 chains of the T cell antigen receptor associate with the ZAP-70 tyrosine kinase and are tyrosine phosphorylated after receptor stimulation

Recent work indicates that signaling events resulting from stimulation of the T cell antigen receptor (TCR) can be initiated by the CD3 complex (gamma, delta, epsilon) as well as the zeta chains of the receptor. To help characterize the signaling function of CD3 we examined its associated tyrosine kinase activity since induction of tyrosine phosphorylation is one of the earliest signaling events. Our results indicate that at least two kinases, lck and ZAP-70, contribute to the CD3-associated kinase activity. A likely target of this activity is the CD3 complex itself since we observed that TCR stimulation resulted in rapid tyrosine phosphorylation of the CD3 epsilon and delta chains. To examine the function of the CD3 epsilon chain in particular, we constructed a chimera that fused the extracellular and transmembrane domains of CD8 to the cytoplasmic domain of CD3 epsilon. This chimera demonstrated that CD3 epsilon was independently capable of associating with proteins having tyrosine kinase activity, including ZAP-70. Our results show that the kinase activity that associates with the CD3 complex has characteristics that are quite similar to the previously characterized zeta-associated kinase activity. This finding suggests that both these components of the TCR initiate signaling events using a common mechanism. However, differences in their signaling function could result from recognition of distinct substrates.     

Formation of prostaglandins and leukotrienes by human lung tissue in vitro after activation by the calcium ionophore A23187

The formation of metabolites of arachidonic acid by the cyclo-oxygenase and lipoxygenase pathways were determined in human lung tissue, obtained from surgery. In this measurement the chopped tissue was incubated with the calcium ionophore A23187. Formation of metabolites from [1-14C] arachidonic acid was also determined. The metabolites were extracted, separated by HPLC and identified by measurement of the absorption spectrum at 280 nm, radioactivity, biological activity and by radioimmunoassay. 6-keto-prostaglandin F1 alpha (6-ketoPGF1 alpha), the metabolite of prostacyclin, is the cyclo-oxygenase product present in the highest amount (400 +/- 49 ng g-1), followed by PGD2 (162 +/- 59 ng g-1) thromboxane B2 (102 +/- 32 ng g-1) PGE2 (104 +/- 46 ng g-1) and PGF2 alpha (58 +/- 26 ng g-1). The amounts of the lipoxygenase products are: leukotriene B4 (LTB4), 163 +/- 100 ng g-1; LTC4, 63 +/- 31 ng g-1 and LTE4 121 +/- 34 ng g-1. From [1-14C] arachidonic acid higher amounts of the cyclooxygenase than of the lipoxygenase products were formed, with the exception of PGE2. The effects of several of these substances on the contraction of human small airway smooth muscle were measured. The contractions, induced by equivalent amounts of LTC4 and a synthetic analogue of thromboxane T X A2 were approximately one hundred times those induced by PGD2, PGF2 alpha and histamine. These results suggest that thromboxane A2 and LTC4 are the most important arachidonic acid metabolites that induce bronchoconstriction in the human lung.     

Comparisons of 17 lots of 2-oxoglutarate, and specifications for use of this substrate in reference methods

We examined 17 lots of 2-oxoglutarate (seven acid forms, three K salt forms, and seven Na salt forms), obtained from eight commercial suppliers, for suitability for measuring aspartate aminotransferase (EC 2.6.1.1) and alanine aminotransferase (EC 2.6.1.2) in human serum. Measurements of the catalytic activity concentrations of these two aminotransferases with each of these 17 preparations were not sufficiently sensitive to distinguish good from poor-quality material. Thus, we ranked these lots for purity, by specific analysis with glutamate dehydrogenase and by liquid chromatography, and determined the water content, acid content, and spectral characteristics of each. On the basis of a 2-oxoglutarate assay value by glutamate dehydrogenase of 98% or greater, we considered seven of the preparations acceptable and 10 unacceptable. The molar absorptivities (L X mol-1 X cm-1, mean +/- SD) of the seven acceptable lots in 1 mol/L HCl were: epsilon 325 nm = 9.12 +/- 0.02 (CV = 0.2%), epsilon 279 nm = 2.63 +/- 0.23 (CV = 9.9%), and epsilon 245 nm = 37.9 +/- 4.1 (CV = 10.9%). Use of these spectrophotometric limits alone unambiguously distinguished the inferior lots of 2-oxoglutarate. We urge the inclusion of detailed spectrophotometric specifications for 2-oxoglutarate in Reference Methods for aminotransferase measurements.     

HPLC法测定注射用氧化型谷胱甘肽二钠有关物质及含量

目的:考察不同色谱条件下注射用氧化型谷胱甘肽二钠有关物质的色谱行为,建立注射用氧化型谷胱甘肽二钠有关物质高效液相色谱分析方法及含量测定方法。方法:固定相为ZorbaxXB-C18(4.6mm×250mm,5μm);流动相为0.006M辛烷磺酸钠溶液-甲醇(95:5);检测波长为210nm,柱温30℃。结果:注射用氧化型谷胱甘肽二钠的线性范围为0.5-10μg,r=0.9999,总有关物质含量小于1%。结论:此法简单,分离度良好,结果准确,可以用于注射用氧化型谷胱甘肽二钠的含量测定和有关物质的检测。     

Two squalene synthase inhibitors, E5700 and ER-119884, interfere with cellular proliferation and induce ultrastructural and lipid profile alterations in a Candida tropicalis strain resistant to fluconazole, itraconazole, and amphotericin B

Three quinuclidine-based squalene synthase (SQS) inhibitors (BPQ-OH, E5700, and ER-119884) were evaluated against five Candida tropicalis strains with different susceptibility profiles to fluconazole (FLC), itraconazole (ITC), terbinafine (TRB), and amphotericin B (AMB). Although the quinuclidine derivatives were inactive against most C. tropicalis strains tested at concentrations up to 16 μg/ml, E5700 and ER-119884 showed antifungal activity against C. tropicalis ATCC 28707, a strain resistant to FLC, ITC, and AMB, with IC₅₀ and IC₉₀ values (i.e., the minimum inhibitory concentrations of the drugs determined as the lowest drug concentrations leading to a 50 and 90% of reduction in turbidity at 492 nm, respectively, after 48 h of incubation) of 1 and 4 μg/ml, respectively. Analysis of free sterols showed that non-treated C. tropicalis ATCC 28707 cells contained only 14-methylated sterols and that treatment with E5700 or ER-119884 led to a marked reduction of squalene content and the complete disappearance of the endogenous sterols. The fatty acid and phospholipid profiles in C. tropicalis ATCC 28707 cells grown in the presence of E5700 and ER-119884 were also markedly altered, with a large increase in the content of linolenic acid (C18:3), associated with a reduction in the content of linoleic (C18:2) and oleic (C18:1) acids. Treatment of C. tropicalis ATCC 28707 with E5700 or ER-119884 IC₅₀ values induced several ultrastructural alterations, including a marked increase in the thickness of the cell wall and the appearance of a large number of electron-dense vacuoles. In conclusion, our results indicated that E5700 and ER-119884 inhibited the growth and altered the lipid prolife and the ultrastructure of a multiple drug-resistant C. tropicalis strain. Therefore, such compounds could act as leads for the development of new treatment options against multidrug resistant Candida species.     

Hypoxia alters the subcellular distribution of protein kinase C isoforms in neonatal rat ventricular myocytes.

Cardiac myocytes coexpress multiple protein kinase C (PKC) isoforms which likely play distinct roles in signaling pathways leading to changes in contractility, hypertrophy, and ischemic preconditioning. Although PKC has been reported to be activated during myocardial ischemia, the effect of ischemia/hypoxia on individual PKC isoforms has not been determined. This study examines the effect of hypoxia on the subcellular distribution of individual PKC isoforms in cultured neonatal rat ventricular myocytes. Hypoxia induces the redistribution of PKC alpha and PKC epsilon from the soluble to the particulate compartment. This effect (which is presumed to represent activation of PKC alpha and PKC epsilon) is detectable by 1 h, sustained for up to 24 h, and reversible within 1 h of reoxygenation. Inhibition of phospholipase C with tricyclodecan-9-yl-xanthogenate (D609) prevents the hypoxia-induced redistribution of PKC alpha and PKC epsilon, whereas chelation of intracellular calcium with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA) blocks the redistribution of PKC alpha, but not PKC epsilon; D609 and BAPTA do not influence the partitioning of PKC alpha and PKC epsilon in normoxic myocytes. Hypoxia, in contrast, decreases the membrane association of PKC delta via a mechanism that is distinct from the hypoxia-induced translocation/activation of PKC alpha/PKC epsilon, since the response is slower in onset, slowly reversible upon reoxygenation, and not blocked by D609 or BAPTA. The hypoxia-induced shift of PKC delta to the soluble compartment does not prevent subsequent 4-beta phorbol 12-myristate-13-acetate-dependent translocation/activation of PKC delta. Hypoxia does not alter the abundance of any PKC isoform nor does it alter the subcellular distribution of PKC lambda. The selective hypoxia-induced activation of PKC isoforms through a pathway involving phospholipase C (PKC alpha/PKC epsilon) and intracellular calcium (PKC alpha) may critically influence cardiac myocyte contractility, gene expression, and/or tolerance to ischemia.     

The effect of amino acid infusion on leg protein turnover assessed by L-[15N]phenylalanine and L-[1-13C]leucine exchange

A stable isotope technique depending on the use of [15N]phenylalanine and [1-13C]leucine to assess exchange was utilized to measure the components of protein turnover of the human leg and the effects of amino acid infusion. Eight healthy subjects (28.5 +/- 2.5 years) were studied when post-absorptive in the basal state and again during infusion of a mixed amino acid solution (55 g l-1, 1.52 ml kg-1 h-1). During the basal period leucine oxidation by the leg was 4.4 +/- 2.0 nmol 100 g-1 min-1 and this increased threefold during amino acid infusion (13.6 +/- 3.1 nmol 100 g-1 min-1, mean +/- SEM, P = 0.003). Amino acid infusion abolished the net negative balance between incorporation of leucine into, and release from, protein (basal, -31.8 +/- 5.8; during infusion, +3.1 +/- 7.1 nmol 100 g-1 P = 0.001). Phenylalanine exchange showed a similar pattern (basal, -13.7 +/- 1.8; during infusion, -0.8 +/- 3.0 nmol 100 g-1 min-1, P = 0.003). Basal entry of leucine into leg protein (i.e. protein synthesis) was 70.0 +/- 10.8 nmol 100 g-1 min-1 and this increased during amino acid infusion to 87.3 +/- 14.1 nmol 100 g-1 min-1 (P = 0.11). Phenylalanine entry to protein also increased with amino acid infusion (29.1 +/- 4.5 vs. 38.3 +/- 5.8 nmol 100 g-1 min-1, P = 0.09). Release from protein of leucine (101.8 +/- 9.1 vs. 84.2 +/- 9.1 nmol 100 g-1 min-1, P = 0.21) and of phenylalanine (42.8 +/- 4.2 vs. 39.1 +/- 4.2 nmol 100 g-1 min-1, P = 0.50) was unchanged by amino acid infusion. The results suggest that, in the post-absorptive state in man, infusion of mixed amino acids, without additional energy substrates; reverses negative amino acid balance by a mechanism which includes stimulation of muscle protein synthesis but which does not alter protein breakdown. Interpretation of the results obtained concurrently on whole-body protein turnover suggests that the increase in muscle protein synthesis contributes substantially to the whole-body increase, but the fall in whole-body breakdown with exogenous amino acids is independent of changes in muscle.     

Specific lysis of allogeneic cells after activation of CD3- lymphocytes in mixed lymphocyte culture

Human CD3- lymphocyte populations were obtained by treating peripheral blood lymphocytes with mAbs directed to CD3, CD4, and CD8 surface antigens. The resulting populations were cultured with irradiated allogeneic cells; at day 4, 100 U/ml IL-2 were added and cultures continued for an additional 10 d. The resulting populations were CD3-CD2+CD7+ and displayed cytolytic activity against PHA-induced blast cells bearing the stimulating alloantigens but not against autologous or unrelated allogeneic blast cells. When CD3- populations were cultured with irradiated autologous cells, no cytolytic activity could be detected either against autologous or allogeneic blast cells. On the other hand, K562 target cells were lysed by both MLC-derived CD3- cell populations regardless of the origin (autologous or allogeneic) of the stimulating cells. CD3- clones were further derived from MLC-stimulated CD3- populations. These clones displayed a cytolytic pattern similar to the original MLC populations as only specific PHA blasts could be lysed. These clones did not express detectable surface TCR-alpha/beta or -gamma/delta molecules and lacked productive mRNA for TCR alpha and beta chains, while small amounts of TCR-gamma mRNA were detectable in one of four clones tested. Also mRNA for CD3 gamma and delta chains were undetectable in all clones, however, CD3 epsilon mRNA was consistently present.     

Severe combined immunodeficiency caused by deficiency in either the delta or the epsilon subunit of CD3

We investigated the molecular mechanism underlying a severe combined immunodeficiency characterized by the selective and complete absence of T cells. The condition was found in 5 patients and 2 fetuses from 3 consanguineous families. Linkage analysis performed on the 3 families revealed that the patients were carrying homozygous haplotypes within the 11q23 region, in which the genes encoding the gamma, delta, and epsilon subunits of CD3 are located. Patients and affected fetuses from 2 families were homozygous for a mutation in the CD3D gene, and patients from the third family were homozygous for a mutation in the CD3E gene. The thymus from a CD3delta-deficient fetus was analyzed and revealed that T cell differentiation was blocked at entry into the double positive (CD4+CD8+) stage with the accumulation of intermediate CD4-single positive cells. This indicates that CD3delta plays an essential role in promoting progression of early thymocytes toward double-positive stage. Altogether, these findings extend the known molecular mechanisms underlying severe combined immunodeficiency to a new deficiency, i.e., CD3epsilon deficiency, and emphasize the essential roles played by the CD3epsilon and CD3delta subunits in human thymocyte development, since these subunits associate with both the pre-TCR and the TCR.     

非靶向脂质组学在子痫前期预测中的应用

目的采用非靶向脂质组学寻找能早期预测子痫前期的生物标志物。方法选取子痫前期高危孕妇,根据后期是否发生子痫前期分为子痫前期组(33例)和无子痫前期组(对照组,33例)。采用超高效液相色谱(UPLC)-飞行时间质谱(TOF)联用技术对所有对象的血清样本进行脂质组学检测。采用差异倍数、非参数Wilcoxon秩和检验、主成分分析(PCA)和偏最小二乘判别(PLS-DA)筛选生物标志物,并对定性的生物标志物进行代谢通路和富集分析。采用受试者工作特征(ROC)曲线评价筛选出的代谢物对子痫前期的诊断价值。结果共筛选出42种生物标志物,其中甘氨胆酸、二十二碳五烯酸和磷脂酰肌醇(PI)(16:1(9Z)/16:0)水平在子痫前期组中明显升高,胆固醇酯(CE)[22:4(7Z,10Z,13Z,16Z)]、二酰甘油(DG)[18:0/20:1(11Z)/0:0]水平明显降低。含2种以上生物标志物的代谢通路分别为鞘脂类代谢途径、甘油磷脂代谢途径和初级胆汁酸生物合成途径,主要参与α-亚麻酸和亚麻酸代谢、缩醛磷脂合成、长链饱和脂肪酸的线粒体β氧化、鞘脂代谢及胆汁酸生物合成。ROC曲线分析结果显示,CE[22:4(7Z,10Z,13Z,16Z)]、DG[18:0/20:1(11Z)/0:0]、二十二碳五烯酸、PI[16:1(9Z)/16:0]及甘氨胆酸诊断子痫前期的曲线下面积分别为0.723、0.715、0.678、0.669和0.660。结论非靶向脂质组学筛选出的生物标志物能有效区分子痫前期患者和无子痫前期孕妇。甘油磷脂代谢、初级胆汁酸代谢、α-亚麻酸和亚麻酸代谢、胆碱代谢与子痫前期发病有关。     

Fc epsilon receptor, a specific differentiation marker transiently expressed on mature B cells before isotype switching

The expression of Fc epsilon R on human lymphocytes was studied with the anti-Fc epsilon R mAbs. Fc epsilon R was expressed on most mu+,delta+ circulating B cells, whereas T cells did not express Fc epsilon R even in patients with hyper-IgE syndrome. B cells with gamma, alpha, or epsilon phenotype did not express Fc epsilon R, moreover its expression could not be induced, suggesting that the Fc epsilon R expression was correlated with isotype switching. mu+delta+ B cells in bone marrow did not express Fc epsilon R, but PHA-sup (supernatant from PHA-stimulated cell cultures) could induce its expression, and the addition of IgE augmented this induction. Recombinant IL-2, IL-1, IFN-gamma or -beta, or purified B cell differentiation factor (BSF-2 B cell-stimulatory factor 2) could not induce Fc epsilon R expression in bone marrow B cells. IFN-gamma inhibited the Fc epsilon R expression induced by PHA-sup, suggesting that the human counterpart of BSF-1 may be responsible for Fc epsilon R expression in bone marrow B cells. B cells from patients with common variable immunodeficiency and ataxia telangiectasia did not express Fc epsilon R, but PHA-sup could induce its expression, indicating that circulating B cells of these patients are at a differentiation stage similar to B cells in bone marrow. The study showed that Fc epsilon R is a B cell-specific differentiation marker, the expression of which is restricted to a defined stage of B cell differentiation.     

Quantitative fluorometric screening test for fecal porphyrins

We describe a fluorometric method for screening and quantifying porphyrins in stool. A small sample of stool is extracted with concentrated HCI and is diluted 200-fold in 3 mol/L HCI before analysis. An excitation scan is done from 350 to 450 nm, monitoring emission at 603 nm. Total porphyrin is estimated at the isosbestic point for coproporphyrin and protoporphyrin (402.5 nm). Monitoring emission at 603 nm eliminates interference from chlorophyll, obviating the need for extraction with ether. The position of the excitation peak gives some indication of the nature of the porphyrins in the stool. The acid extract can be injected directly into an HPLC system for fractionation studies. Our method correlates well with the spectrophotometric method developed by Lockwood et al. (Clin Chem 1985;31:1163-7). However, in our method, the sample is easier to process and the assay has higher sensitivity than their assay. The reference interval for porphyrin in healthy individuals by the fluorometric method is less than 300 nmol/g dry weight. We can detect as little as 1 nmol of porphyrin per gram (dry weight) of stool. Results of the method vary linearly with stool porphyrin concentrations as great as 4000 nmol/g dry weight. The within-run imprecision of the method is 3%.     

Effects of butter and soybean oils on solid-phase gastric emptying in patients with functional dyspepsia

BACKGROUND: To determine whether vegetable fats cause a slower or quicker rate of gastric emptying (GE) than animal fats, we evaluated the effect of animal butter and vegetable soybean oil on solid-phase GE in patients with functional dyspepsia. METHODS: Twenty-seven patients with functional dyspepsia were enrolled in this study. Radionuclide-labeled solid meals were used to evaluate GE. A study meal was composed of 206.8 kcal to 9.2 g protein, 45 g carbohydrate, and 10 g fat (formula 1, with animal butter: 26.2% saturated palmitic acid, 29.1% unsaturated oleic acid, 3.5% linoleic acid, and 0.5% linolenic acid; formula 2, with vegetable soybean oil: 11.0% saturated palmitic acid, 23.4% unsaturated oleic acid, 53.7% linoleic acid, and 7.8% linolenic acid). Each patient received formulas 1 and 2 as study meals on separate days. GE was represented by the gastric retention ratio of the study meal at 90 min (RR90): RR90 = residual radioactivity within the region of interest (ROI) covering the entire stomach at 90 min divided by the initial radioactivity within the ROI at 0 min. RESULTS: The RR90 was 0.648 +/- 0.156 for formula 1 and 0.600 +/- 0.131 for formula 2. There was no significant difference for the RR99 between formulas 1 and 2 (paired Student's t test, p > 0.05). Of the 27 patients, 12 (44.4%) demonstrated an increased RR99 from formula 1 to formula 2, and the RR90 of remaining 15 (55.6%) patient decreased. In addition, neither the patients with increased RR90 nor those with decreased RR90 showed a difference of symptoms between the two study meals. CONCLUSION: Our data suggest that there is no difference between these two types of fat on gastric emptying.