D-mannose as a preservative of glucose in blood samples

We evaluated whether any monosaccharides inhibit glycolysis in erythrocytes and discovered that D-mannose does. In the presence of D-mannose, glucose can be accurately measured by either the hexokinase procedure or the glucose oxidase procedure. In comparison studies with other glucose preservatives, we found that after 2 h at room temperature glucose decreased by 21 (SD 13) mg/L in D-mannose-treated blood, 93 (SD 10) mg/L in sodium fluoride-treated blood, 28 (SD 21) mg/L in ice-cooled blood, and 144 (SD 28) mg/L in control blood (no preservative treatment). Because D-mannose acted in the early phase of glycolysis, it was a more effective preservative than sodium fluoride; moreover, its use did not preclude measurement of sodium and potassium in the blood samples. D-Mannose did not interfere with other routine chemical tests except for the assay of creatine kinase involving coupled enzymes hexokinase/glucose-6-phosphate dehydrogenase. Creatine kinase could be correctly assayed in the presence of D-mannose by using glucokinase instead of hexokinase. D-Mannose can be used with or without anticoagulant and is compatible with most types of multi-channel automated analyzers.     

草酸钠-氟化钠采血管中血样离心前放置时间对血浆葡萄糖测定的影响

目的探讨草酸钠-氟化钠采血管中血样在离心前放置的时间对血浆葡萄糖测定结果产生的影响。方法收集102例志愿者的血样,将同一患者标本分别置于4管草酸钠-氟化钠采血管和4管带促凝剂分离胶采血管内,草酸钠-氟化钠采血管血样在放置0、30、60、120min后离心,带促凝剂分离胶采血管血样凝固后离心,分别放置0、30、60、120min后和草酸钠-氟化钠采血管一同测定葡萄糖浓度。结果草酸钠-氟化钠采血管中血样的血浆葡萄糖浓度随离心前放置时间增加而降低,带促凝剂分离胶采血管中样本葡萄糖浓度变化不具有统计学意义。结论草酸钠-氟化钠采血管中血样离心前放置时间对血浆葡萄糖测定结果有影响,放置时间增加会导致测定值降低。     

Sodium iodoacetate as an antiglycolytic agent in blood samples.

We evaluated the effect of sodium iodoacetate on glycolysis in a series of randomly selected blood samples from patients. Glucose values for serum and for serum with added sodium fluoride (2.5 g/liter) or sodium iodoacetate (2 g and 0.5 g/liter) were compared at room temperature. Respective declines in glucose values averaged 170, 40, 30, and 30 mg/liter after 24 h. Iodoacetate-preserved (0.5 g/liter) samples showed no visible hemolysis. Results of determinations of urea with urease and of other tests on SMA 12/60 (Technicon) panels were unaffected.     

不同浓度氟化钠抗凝血对POCT血糖仪校准结果干扰影响的研究

目的研究不同浓度氟化钠抗凝血对POCT血糖仪结果干扰情 况。方法20例研究对象每人采集1支EDTA-K2样本管和6支含不同 浓度氟化钠的(NaF)EDTA-K2样本管静脉血,每管2 ml,POCT血糖仪与生化仪检测每管血 糖水平,比较不同浓度氟化钠组间样本管血糖水平差异及相同氟化钠浓度样本管POCT血糖仪 与生化仪检测血糖水平差异。结果POCT血糖仪检测不同浓度氟化钠 样本管血糖水平组间比较,其差异有统计学意义( F=12.192,P <0.001);采用LSD法进 行多重比较,不含NaF组血糖水平与其它含NaF组血糖水平比较,不含NaF组血糖水平明显高 于其它含NaF组血糖水平( t=13.556,14.223,13.512,14.012,13.876,13.864, 均P <0.001),含NaF不同组间血糖水平比较,差异无统计学意义( t=0.352,0.412,0 .386,0.411,0.395,0.414,均P >0.05);生化仪检测不同浓度氟化钠组间血糖水 平比较,其差异无统计学意义( F=0.428,P =0.829)。不含氟化钠样本管两仪器检测血 糖水平比较,差异无统计学意义( t=0.457,P =0.358);含相同浓度氟化钠样本管两仪 器检测血糖水平比较,生化仪检测血糖水平明显高于POCT血糖仪水平( t=-14.415,-14. 746,-13.613,-14.108,-15.253,-14.069,均P <0.01)。结论 氟化钠对采用葡萄糖脱氢酶法POCT血糖仪结果有明显抑制作用,抑制程度与氟化钠浓 度无明显相关,氟化钠不宜作为葡萄糖脱氢酶法POCT血糖仪比对标本的糖酵解抑制剂。     

Differential activation of rabbit femoral arteries by aluminum fluoride and sodium fluoride

The effect of fluoride (NaF; 10 mM sodium fluoride plus deferoxamine to chelate contaminating aluminum) and fluoride plus aluminum fluorides (AlF; 10 mM sodium fluoride plus 20 microM aluminum chloride) on activation of rabbit femoral arteries was investigated. AlF and NaF produced large increases in stress (force/muscle cross-sectional area), but temporal changes were dissimilar, as were other indices of muscle activation. Stress produced by NaF developed slowly and only after a long delay of about 15 min, whereas stress produced by AlF developed rapidly after a delay of only about 5 min. NaF-induced contractions were more sustained than AlF-induced contractions. Both AlF and NaF increased the level of cross-bridge phosphorylation and the velocity of muscle shortening, but at comparable stresses, AlF produced greater increases than did NaF. AlF produced a large increase in lP production, whereas NaF produced a small increase. Also, AlF-induced stress was largely insensitive to inhibition by the calcium channel blocker, nifedipine (1 microM), whereas NaF-induced stress was largely inhibited by nifedipine. However, in tissues depleted of calcium, both agents produced potent contractions when CaCl2 was added back to the tissues (EC50 values for AlF, NaF, histamine, phenylephrine and KCl were, respectively, 0.057, 0.085, 0.11, 0.11 and 0.23 mM). AlF, but not NaF, strongly desensitized arteries to phenylephrine, causing a 73% reduction in the ability of phenylephrine to achieve maximum steady-state stress. These data suggest that fluoride contracted rabbit femoral arteries by stimulating L-type calcium channels, and that aluminum fluoride stimulated phospholipase C, producing additional muscle activation.     

Otosclerosis 2: the medical management of otosclerosis

The rationale for medical therapy for otospongiosis is to slow down and eventually stop the phase of bone resorption. There is some increase in the incidence of stapedial otospongiosis in a low‐fluoride area compared with a high‐fluoride area. Sodium fluoride treatment has a role to play in preventing the onset and progression of hearing loss in patients suffering from otosclerosis. Sodium fluoride therapy has been shown to have some beneficial effect on dizziness associated with otosclerosis. In view of the possibility of systemic side effects of sodium fluoride therapy, a regular follow up of patients is warranted. Biphosphonates can be used as an alternative treatment to sodium fluoride in cases where the patient is intolerant to sodium fluoride therapy. Hearing aid is also a treatment option, but it does not halt the disease process.     

Calcium Neutralizes Fluoride Bioavailability in a Lethal Model of Fluoride Poisoning

Objectives: Acute systemic fluoride poisoning can result in systemic hypocalcemia, cardiac dysrhythmias, and cardiovascular collapse. Topical and intraarterial therapy with calcium or magnesium salts reduces dermal injury from fluoride burns. The mechanism of these therapies is to bind and inactivate the fluoride ion. The purpose of this study is to evaluate the effect of calcium and magnesium to decrease the bioavailability of fluoride in a lethal model of fluoride poisoning. Methods: In preliminary studies, we determined that fluoride 3.6 mM/kg intraperitoneally in the form of sodium fluoride was uniformly and rapidly fatal in a mouse model. Using this fluoride dose, we performed a controlled, randomized, blinded study of low-and high-dose calcium chloride (1.8 and 3.6 mM/kg intraperitoneally, respectively) and magnesium sulfate (3.6 mM/kg intraperitoneally) to decrease the bioavailability of the fluoride ion. After injection with sodium fluoride, animals were immediately treated with injections of sodium chloride (control), calcium chloride (low- or high-dose), or magnesium sulfate. The major outcome was 6-hour survival using a Cox Proportional Hazard model. Results: All untreated animals died within 60 minutes. Using a Cox Proportional Hazard model, each 1.8 mM/kg dose of calcium chloride administered reduced the risk of death by 33%. Magnesium sulfate treatment was not associated with a hazard reduction. Conclusion: Calcium chloride administered simultaneously with sodium fluoride reduces the bioavailability of fluoride poisoning in a mouse model. The equivalent dose of magnesium sulfate does not significantly decrease fluoride bioavailability.     

Bacteriolytic Action of Fluoride Ions

Bacillus subtilis, Neisseria subflava, and LYT coccus were found to undergo massive lysis after growth in media containing 0.01 to 10 mM NaF. When cells of these organisms were transferred from late-exponential-phase cultures to 0.02 M sodium phosphate buffer plus 0.1 M KCl, they underwent spontaneous autolysis. Cells grown in media with fluoride were more liable to autolysis, and walls isolated from them also showed enhanced autolytic sensitivity, even though added fluoride did not directly stimulate autolysins. Sporadic or partial lysis occurred in populations of Streptococcus sanguis and Streptococcus mutans BHT or LM-7 after growth in fluoridated media. Most bacteria that were tested did not undergo fluoride-induced lysis. However, cells of all test bacteria were found to have reduced amounts of peptidoglycan per unit of cell weight when grown in the presence of fluoride. Incorporation of labeled lysine or glucosamine into peptidoglycan (Park-Hancock residue) was stimulated, instead of inhibited, by fluoride. However, fluoride also stimulated the loss of radioactivity from Park-Hancock residues of cells that had previously incorporated labeled lysine or glucosamine. Thus, fluoride appeared to enhance peptidoglycan turnover, and this turnover reduced the peptidoglycan contents of all bacteria tested, but induced lysis in only those bacteria that normally have highly active autolytic systems.     

In vitro immune modulation of polymorphonuclear leukocyte adhesiveness by sodium fluoride

We investigated the influence of sodium fluoride on polymorphonuclear leukocyte (PMN) adhesiveness in a healthy subject with low serum levels of fluoride. The PMN were separated from venous blood, and the percentages of adhered and unadhered cells were determined in vitro in plastic culture plates. The cells were cultured with five different fluoride concentrations ranging from 6.25 10(-2) microM to 4.0 microM in the presence and absence of autologous serum. PMN adhesiveness in both the presence and in the absence of autologous serum was 98.5%; the addition of fluoride had no effect on the results in the absence of serum. However, in the presence of autologous serum, PMN adhesiveness decreased significantly with the addition of fluoride (P < 0.05) from 0.5 microM. The decrease was smaller (1.1%) at a concentration of 0.125 microM, and larger at 12 times this concentration of fluoride (52.7%). We conclude that sodium fluoride reduces PMN adhesiveness in a dose-dependent manner. The effect is not direct, but should be modulated by a seric factor.     

Serum cystatin C in renal transplant patients

BACKGROUND: Waiting temperature before centrifugation and anticoagulants used, markedly effect total homocysteine concentrations. The aim of this study was to investigate the effect of different anticoagulants and temperature on plasma homocysteine levels. METHODS: We studied total homocysteine concentrations in 23 healthy subjects. Blood was drawn in K(3)EDTA, sodium citrate- or sodium fluoride-containing tubes, and kept at 0 degrees C or 22 degrees C for 3 h. Total homocysteine measurements were performed with fluorescence polarization immunoassay (FPIA) method. We compared all results with baseline EDTA values (samples put on crushed ice and centrifuged immediately) recommended in literature for reference handling. RESULTS: At 22 degrees C, the tubes containing sodium citrate and sodium fluoride showed significantly higher total homocysteine concentrations than their respective baseline values (p=0.000). However, sodium fluoride tubes were not significantly different than baseline EDTA levels. Waiting 3 h at 0 degrees C did not effect sodium citrate and EDTA plasma total homocysteine concentrations when compared to baseline EDTA, but sodium fluoride-containing plasma levels were significantly decreased (p=0.000). CONCLUSIONS: According to our results, the most available and practical temperature and anticoagulant for total homocysteine determination is sodium fluoride at room temperature up to 3 h.     

氟纳米羟基磷灰石封闭人离体牙牙本质小管的生物相容性

背景:氟纳米羟基磷灰石具有抗酸性,与牙体组织成分相似,生物相容性好,对牙釉质具有再矿化功能等特点。目的:观察氟纳米羟基磷灰石对牙本质小管的封闭效果。方法:选取56颗健康离体牙,随机分为4组,分别为纳米含氟羟基磷灰石组、纳米羟基磷灰石组、氟化钠组及空白对照组。实验各组每天早晚分别用3组材料涂刷牙本质小管外层的牙本质2次,2min/次,置于人工唾液37℃恒温箱中保存;7d后将牙纵向劈开为即刻组,模仿人日常刷牙方法用去离子水涂刷实验区100次再将其纵向劈开为磨损组,扫描电镜观察牙本质表面实验区和剖面牙本质小管堵塞率及封闭深度。结果与结论:空白组牙本质小管完全开放,扫描电镜观察氟纳米羟基磷灰石对牙本质小管的封闭效果明显优于其他3组;即刻组和磨损组封闭效果均为纳米含氟羟基磷灰石>纳米羟基磷灰石>氟化钠。结果显示纳米含氟羟基磷灰石小管堵塞效果和封闭深度均显著高于纳米羟基磷灰石﹑氟化钠材料。     

The influence of age on the distribution, metabolism and excretion of methoxyflurane in Fischer 344 rats: a possible relationship to nephrotoxicity.

Age as a factor in methoxyflurane nephrotoxicity was evaluated in Fischer 344 rats of various ages by determination of: 1) serum inorganic fluoride and methoxyflurane concentrations, and urinary inorganic fluoride excretion in methoxyflurane-exposed rats; 2) liver microsomal methoxyflurane defluorinase activity; and 3) distribution of injected sodium fluoride. Only rats in the youngest age group (6 weeks) did not develop nephrotoxicity after anesthesia. Older rats had a biphasic rather than a monophasic decay in serum methoxyflurane concentration and also had increased serum inorganic fluoride concentration and urinary inorganic fluoride excretion. Older rats also excreted a greater proportion of an injected dose of sodium fluoride compared to young rats. Microsomal methoxyflurane defluorinase specific activity was similar among rats of all ages. It is likely that increased availability of methoxyflurane due to its greater storage in fat led to more inorganic fluoride production in older compared to younger rats. Bone sequestration of inorganic fluoride in younger rats probably accounts for decreased serum inorganic fluoride levels in that group. Both factors cause significant differences in renal exposure to inorganic fluoride; thus the risk of nephrotoxicity is less in younger animals.     

Postmenopausal osteoporosis: treatment with low-dose sodium fluoride and estrogen

Eleven menopausal patients were treated for 12 to 18 months with low-dose sodium fluoride and calcium. Six patients also received estrogen replacement. A significant increase in spine or hip bone mineral density measured by dual photon absorptiometry was observed in all patients. The estrogen-treated group had the greatest increase in bone density. Addition of estrogen seems to supplement bone gain and allow sodium fluoride to be administered in lower doses, which are easily tolerated and yet effective.     

Purification and characterization of a mannose-containing disaccharide obtained from human pregnancy urine. A new immunoregulatory saccharide

Endogenous mammalian lectin-like sugar-binding molecules have been previously described that have immunoregulatory properties. Further, the addition of defined simple saccharides to lymphocyte cultures has been shown to inhibit a variety of in vitro lymphocyte functions, presumably because these sugars are able to compete with the binding of endogenous lectins to critical membrane receptors. In this report, we describe the isolation and characterization of a D-mannose-containing disaccharide in human pregnancy urine that inhibits the proliferative response of human T lymphocytes. The inhibitory disaccharide was purified to homogeneity by sequential steps including affinity chromatography on immobilized concanavalin A and molecular sizing on Sephadex G-75 and then Fractogel 40S columns, with final purification on high-performance thin-layer chromatography. By mass spectrometry of the purified material as its permethylated derivative, the deduced structure of this compound was alpha-D-Manp 1-6-D-Man. To confirm that this disaccharide was in fact immunosuppressive, an identical disaccharide was prepared by sequential digestion of yeast cell wall polysaccharide. The urinary and yeast disaccharides had identical immunosuppressive properties. It has been previously reported that D-mannose is inhibitory for antigen-specific proliferative assays in the range of 10-50 mM. The purified alpha-D-Manp 1-6-D-Man disaccharide was inhibitory at 100-fold-lower concentrations. Further, while D-mannose inhibits T cell proliferation when added at anytime up to 24 h before harvest of a 6-d lymphocyte culture, alpha-D-Manp 1-6-D-Man disaccharide was inhibitory only if added at the initiation of culture and had no inhibitory effect if added just 24 h later. These data support the concept that simple sugar compounds can exhibit marked immunoregulatory activity in vitro. The impact of these molecules on the regulation of immune responses in vivo is unknown, as is their precise mechanism of action, but structural and chemical identification should now permit a detailed analysis of these issues.     

Enzymatic determination of D-mannose in serum

A new and simple enzymatic assay for measuring D-mannose in serum is described. Endogenous glucose is eliminated from serum by use of glucose oxidase (EC 1.1.3.4) and catalase (EC 1.11.1.6). D-Mannose concentration is calculated from the increase in NADH formation after mannosephosphate isomerase (EC 5.3.1.8) is added. This increase is a result of coupling the following series of enzymes: hexokinase (EC 2.7.1.1), glucosephosphate isomerase (EC 5.3.1.9), and glucose-6-phosphate dehydrogenase (EC 1.1.1.49, NAD+-dependent). The study included subjects who were healthy volunteers and patients with suspected or proven fungal infections.     

A micro method for direct determination of ionic fluoride in body fluids with the hanging drop fluoride electrode

A simple method for direct determination of ionic fluoride in 5 μl samples of body fluids with the hanging drop fluoride electrode, using sodium acetate buffer (pH 4.8) is described. The hanging drop electrode should prove useful in experimental investigations employing small laboratory animals and in clinical laboratories.     

EFFECT OF ENZYME INHIBITORS AND ACTIVATORS ON THE MULTIPLICATION OF TYPHUS RICKETTSIAE : I. PENICILLIN,PARA-AMINOBENZOIC ACID,SODIUM FLUORIDE,AND VITAMINS OF THE B GROUP

By injection into typhus-infected yolk sacs, a number of agents were tested for possible inhibition or acceleration of rickettsial growth. The previously reported rickettsiostatic activity of penicillin was further confirmed. Para-aminobenzoic acid, in single injections of 6.6 mg. and 3.3 mg. giving initial concentrations of approximately 1:6000 and 1:12,000 was found to have rickettsiostatic activity approximately equal to that of penicillin. No conclusion could be drawn regarding the possibility of a synergistic action of para-aminobenzoic acid and penicillin. Para-aminobenzoic acid neutralized with sodium hydroxide was found to be as effective as the acid itself, when given in single injections of 6.6 mg. Sodium benzoate, as Well as the ortho and meta forms of aminobenzoic acid were found to be ineffective when given in similar amounts. Para-aminobenzoic acid, when added to the food in a concentration of 3 per cent, was shown to have a remarkably effective chemotherapeutic action on murine typhus infection in mice. Sodium fluoride was found at times to accelerate the growth of rickettsiae in the yolk sac, and to cause heavy infection under conditions such that the controls showed practically no multiplication of the organism. When rickettsiostatic substances (penicillin and para-aminobenzoic acid) were combined with sodium fluoride, their rickettsiostatic activity was not demonstrably changed. Other agents studied and found not to affect rickettsial multiplication are listed. The possible mechanisms involved in the observed inhibition and stimulation of rickettsial growth under these conditions are discussed.     

硅酸三钙封闭牙本质小管的作用

背景：多项体外实验证实硅酸三钙不仅可以通过自固化过程与牙本质紧密结合,而且在生理环境下能诱导牙本质再矿化,有效阻塞牙本质小管。 目的：进一步验证硅酸三钙对牙本质小管的封闭作用。 方法：选择正畸患者拔除的第一前磨牙制作离体牙本质盘36块,分别经0.29 mol/L EDTA 内浸置2 min,6%柠檬酸蚀1 min 后冲洗,蒸馏水超声清洗20 min 3种方法预处理,模拟具有牙本质小管不同开放程度的牙本质敏感症。以上每组随机分为3个亚组,即硅酸三钙组、氟化钠对照组、空白对照组,前2组每天早晚分别用对应材料涂刷表面,2 min/次,空白对照组不处理,其余时间全部置于人工唾液37℃恒温箱中保存。14 d后通过扫描电镜观察各组处理前后牙本质形态,并计算开放牙本质小管直径和面积。 结果与结论：经不同预处理后牙本质小管都呈开放状态,但柠檬酸和EDTA预处理溶液较蒸馏水有更强的脱矿作用,牙本质小管更加清晰。各组经氟化钠或硅酸三钙涂擦后,牙本质小管口有不同程度沉积物,且开放牙本质小管面积及平均直径较空白对照组小（P〈0.05）;经硅酸三钙涂擦的牙本质小管几乎完全均质封闭,偶见有单个孤立开放的牙本质小管口,开放牙本质小管面积及平均直径都明显低于氟化钠对照组（P〈0.05）。证实硅酸三钙可有效封闭牙本质小管,且效果优于氟化钠;在治疗牙本质过敏时,如果先用EDTA或酸蚀剂处理,脱敏效果会更完善。     

Reversal of infectious mononucleosis-associated suppressor T cell activity by D-mannose

Epstein-Barr virus-induced infectious mononucleosis (IM) is associated with the activation of suppressor T lymphocytes that profoundly inhibit immunoglobulin (Ig) production in vitro. We have examined the nature of signals operating in the interaction between IM suppressor T cells and their targets, and explored the possibility that a lectin-like receptor molecule and its specific sugar might provide specificity to this interaction. When D-mannose or some of its derivatives, including alpha-methyl-D-mannoside, mannose-6-phosphate, and mannan, were added to suppressed cultures containing IM T lymphocytes and pokeweed mitogen (PWM)-stimulated normal mononuclear cells, a significant enhancement of Ig production was observed. These sugars had little or no effect on Ig production by the PWM-stimulated responder cells alone and thus the enhanced Ig production could be attributed to the reversal of suppression in the co-cultures by these sugars. This was further confirmed by the observation that the sugars were effective only if present during the first 24 h of culture, a time when IM suppressor T cells exert their principal effect. The effect of sugars on Ig production by suppressed cultures was similar to that achieved by decreasing by about fourfold the number of IM T cells in culture. The effect of the sugars is unlikely to represent a form of nonspecific toxicity, since inhibited cultures become responders in the presence of the sugar. Furthermore, toxicity restricted to the suppressor T cells is unlikely, since preincubation of the T cells with the sugars did not reduce their subsequent ability to suppress in secondary indicator cultures. In addition, there was no correlation between the effect of the sugars on T cell proliferation and their effect on T cell-mediated suppression. The reversal of suppression by sugars was dose dependent and demonstrated stereo-specificity in that L-mannose was without effect while D-mannose reversed suppression. These data indicate that D-mannose and some of its derivatives consistently reverse suppression of Ig production by IM T cells and strongly suggest a role for saccharides as critical components in the cellular receptors involved in certain physiologic immune cell interactions.