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Biomedical subjects

M Shiga

Publications and source records attributed to M Shiga.

At least 37 records · Page 2Linked to original sources
PubMed1999

Suppression of airway inflammation by theophylline in adult bronchial asthma.

BACKGROUND: Chronic continuous airway inflammation caused by eosinophils has been noted to play critical roles in the pathophysiology of bronchial asthma, in addition to reversible obstruction and hypersensitivity of the respiratory tract. Therefore, suppression of chronic airway inflammation has become more important in asthma treatment. Although theophylline has been a conventionally used bronchodilator, it has been recently reported to have concurrent anti-inflammatory effects. OBJECTIVE: Accordingly, we studied the effects of a slow-release theophylline preparation, Theolong, on airway inflammation. METHODS: Administration of Theolong 400 mg/day to 24 patients with mild or moderate asthma and measuring eosinophil cationic protein (ECP), a marker of airway inflammation, and eosinophils in sputum and peripheral blood at 4 and 8 weeks. RESULTS: As a result, sputum ECP, serum ECP and sputum eosinophil count (%) were significantly lowered after 4 and 8 weeks. CONCLUSION: Thus, in the theophylline-administered group, slow-release theophylline, Theolong, was effective in treating asthma, with anti-inflammatory effects on inflammatory cells besides its bronchodilator action.

Administration, Oral↗
PubMed1999

Crucial role of group IIA phospholipase A(2) in oleic acid-induced acute lung injury in rabbits.

Group IIA secretory phospholipase A(2) (sPLA(2)) has been implicated in a variety of inflammatory diseases including acute lung injury (ALI); however, the role of sPLA(2) in this disorder remains unclear. The aim of the present investigation was to examine the role of this enzyme in a model of ALI induced by oleic acid (OA) in rabbits by testing human group IIA phospholipase A(2) (PLA(2)) inhibitor, S-5920/LY315920Na. Experimental groups consisted of a saline control group (n = 8), an OA control group (n = 10) infused intravenously with OA (0.1 ml/kg/h for 2 h), and three groups given OA + S-5920/LY315920Na (three different doses, n = 8, respectively). Infusion of OA provoked pulmonary hemorrhage and edema formation, protein leakage, and massive neutrophil infiltration, resulting in severe hypoxemia and impaired lung compliance. PLA(2) activity was detected in the bronchoalveolar lavage fluid (BALF), but not plasma, which correlated well with severity of lung injury in this model. Pretreatment with S-5920/LY315920Na diminished the OA-induced PLA(2) activity in the BALF and dose-dependently attenuated the previously described lung injury induced by OA, accompanied by protection against lung surfactant degradation and production of thromboxane A(2) (TXA(2)) and leukotriene B(4) (LTB(4)). S-5920/LY315920Na also inhibited the OA-induced production of interleukin-8 (IL-8), both in plasma and BALF. Thus, sPLA(2) appears to play a key role in OA-induced lung injury, suggesting that the group IIA PLA(2) inhibitor may be a promising agent for patients with acute respiratory distress syndrome (ARDS).

Acetates↗
PubMed1998

Comparison of pirenzepine, ranitidine, and pirenzepine-ranitidine combination for reducing preoperative gastric fluid acidity and volume in children.

We conducted a two-part controlled study to evaluate the efficacy of preoperative oral pirenzepine (muscarinic receptor antagonist known to inhibit gastric secretion), ranitidine, and the combination pirenzepine-ranitidine in controlling gastric fluid pH and volume in 210 ASA I children, aged 2-14 yr, undergoing elective surgery. In the first part of the study (n = 90), the proportion of children considered at risk for aspiration pneumonitis was reduced with pirenzepine 25 mg (P < 0.05) but not with 12.5 mg. In the second part of the study, the other 120 children were allocated randomly to one of four groups: pirenzepine 25 mg with placebo; ranitidine 75 mg with placebo; pirenzepine 25 mg with ranitidine 75 mg; and placebo and placebo. These medications were administered 1 h before anaesthesia. After tracheal intubation, volume and pH of the gastric fluid aspiration via a multiorifice orogastric tube were measured. Pirenzepine 25 mg decreased gastric fluid volume (P < 0.05) but failed to increase gastric pH. Ranitidine 75 mg increased gastric pH (P < 0.05) but failed to decrease fluid volume. The pirenzepine-ranitidine combination reduced gastric fluid acidity and volume (P < 0.05).

Adolescent↗
PubMed1998

The inhibitory effects of thiopental, midazolam, and ketamine on human neutrophil functions.

UNLABELLED: We investigated the effect of thiopental, midazolam, and ketamine (at clinically relevant concentrations and at 0.1 and 10 times these concentrations) on several aspects of human neutrophil functions. The three intravenous (i.v.) anesthetics significantly decreased chemotaxis, phagocytosis, and reactive oxygen species (ROS) (O2-, H2O2, OH) production of neutrophils in a dose-dependent manner. At clinically relevant concentrations, thiopental and midazolam significantly depressed these neutrophil functions. However, ketamine at the clinical plasma concentration did not impair chemotaxis or ROS production, except phagocytosis. In contrast, the three anesthetics had no effect on the levels of ROS production by a cell-free ROS generating system. In addition, intracellular calcium concentrations in neutrophils stimulated by N-formyl-L-methionyl-L-leucil-L-phenylalanine were dose-dependently decreased in the presence of each of the three anesthetics. The suppression of an increase in intracellular calcium concentrations may be responsible for the inhibition of neutrophil functions by the i.v. anesthetics. IMPLICATIONS: Neutrophils play an important role in the antibacterial host defense system and autotissue injury. We found that thiopental and midazolam (but not ketamine), at clinically relevant concentrations, impaired the neutrophil functions.

Anesthetics↗
PubMed1998

Propofol inhibits human neutrophil functions.

UNLABELLED: Neutrophils play important roles in the antibacterial host defense mechanism and in the pathogenesis of tissue injury. Propofol has been reported to impair the production of reactive oxygen species from neutrophils. We examined the effect of propofol (2,6-diisopropylphenol), at clinically relevant concentrations and at 10 and 100 times this concentration, on several aspects of human neutrophil functions using an in vitro system. Propofol significantly inhibited chemotaxis, phagocytosis, and reactive oxygen species (ROS) (O2-, H2O2, OH) production of neutrophils in a dose-dependent manner. At clinically relevant concentrations, propofol suppressed these neutrophil functions, but it did not decrease ROS generation by the cell-free (xanthine-xanthine oxidase) system. Increase in intracellular calcium concentrations in neutrophils stimulated by N-formyl-L-methionyl-L-leucyl-L-phenylalanine was dose-dependently attenuated by propofol. This decreasing effect on [Ca2+]i in neutrophils may represent one of the mechanisms responsible for the inhibition of neutrophil functions by propofol. IMPLICATIONS: Neutrophils play a pivotal role in the antibacterial host defense system and tissue injury. We found that at clinically relevant concentrations, propofol impaired neutrophil functions. Further studies may determine whether this impairment, observed in vitro, leads to clinical immunological suppression.

Anesthetics, General↗
PubMed1998

Effects of oral clonidine premedication on plasma glucose and lipid homeostasis associated with exogenous glucose infusion in children.

BACKGROUND: Oral clonidine may influence plasma glucose and lipid homeostasis by modulating endocrinologic responses to surgical stress. The effect of oral clonidine premedication on plasma glucose and lipid homeostasis associated with exogenous glucose infusion were investigated in children undergoing minor surgery. METHODS: Otherwise healthy children (n, 120; aged 3-13 yr) were assigned randomly to six groups according to the glucose concentration of the intravenous solution (0%, 2%, or 5%, at a rate of 6 ml kg(-1) x h(-1)) and the preoperative medications (4 microg/kg clonidine or placebo given 100 min before anesthesia) they were to receive. The plasma concentrations of glucose, nonesterified fatty acid, ketone bodies, epinephrine, norepinephrine, and cortisol were determined. RESULTS: Infusion of 5% glucose caused hyperglycemia (mean glucose concentration >200 mg/dl) in six children receiving placebo and two receiving clonidine. Although the mean plasma glucose concentration increased in three placebo groups, it was unchanged and the plasma concentrations of total ketone bodies and nonesterified fatty acid were increased in children receiving clonidine and glucose-free solution. The plasma epinephrine, norepinephrine, and cortisol levels in children receiving placebo increased in response to surgery. Clonidine attenuated the increase in catecholamines and cortisol. CONCLUSIONS: Oral clonidine premedication attenuated the hyperglycemic response, probably by inhibiting the surgical stress-induced release of catecholamines and cortisol. Infusion of 2% of glucose maintained plasma glucose concentrations within physiologic ranges in children receiving clonidine.

Administration, Oral↗
PubMed1998

Intravenous lidocaine attenuates acute lung injury induced by hydrochloric acid aspiration in rabbits.

BACKGROUND: Neutrophils play a crucial role in the pathogenesis of acid-induced acute lung injury. Lidocaine inhibits the function of neutrophils. This study aimed to determine whether lidocaine attenuates acute lung injury induced by hydrochloric acid (HCl) instillation. METHODS: In study 1, rabbits were divided into four groups (n = 7 each). Lung injury was induced by intratracheal HCl (0.1 N, 3 ml/kg) in two groups. The other two groups received saline intratracheally. Lidocaine given intravenously (2 mg/ g bolus + 2 mg x kg(-1) x h(-1) infusion) was started 10 min before intratracheal instillation in one HCl and one saline group, and saline was given intravenously in the other two groups. In study 2, rabbits (four groups of seven animals each) received HCl (0.1 N, 3 ml/kg) intratracheally. Treatment with intravenous lidocaine was started 10 min before, 10 min after, or 30 min after acid instillation, or saline was given intravenously 10 min before instillation. RESULTS: In study 1, HCl caused deterioration of the partial pressure of oxygen (PaO2), lung leukosequestration, decreased lung compliance, and increased the lung wet-to-dry weight ratio and albumin, interleukin-6 (IL-6), and IL-8 levels in bronchoalveolar lavage fluid. Lidocaine pretreatment attenuated these changes. Hydrochloric acid increased superoxide anion production by neutrophils and caused morphologic lung damage, both of which were lessened by lidocaine. In study 2, lidocaine given 10 min after acid instillation was as effective as pretreatment in PaO2, lung mechanics, and histologic examination. However, PaO2 changes in lidocaine 30 min after injury were similar to those in saline given intravenously. CONCLUSIONS: Intravenous lidocaine started before and immediately after acid instillation attenuated the acute lung injury, in part by inhibiting the sequestration and activation of neutrophils.

Anesthetics, Local↗
PubMed1997

Prostaglandin E1, lidocaine, and prostaglandin E1-lidocaine combination for attenuating cardiovascular responses to extubation.

PURPOSE: Tracheal extubation produces haemodynamic changes that may cause myocardial ischaemia in patients with coronary arterial disease. Intravenous infusion of prostaglandin E1 (PGE1) attenuated the hypertensive response to tracheal extubation but failed to blunt the tachycardia, which was attenuated by intravenous lidocaine. Thus, we investigated whether a combination of PGE1 and lidocaine can overcome the drawbacks of treatment with PGE1 alone. METHODS: One hundred adult patients (ASA 1) undergoing elective minor surgery were randomly assigned to receive one of four treatments: saline (as a control), 1 mg-kg-1 lidocaine, infusion of 0.1 microgram-1.kg-1.min-1 PGE1, or infusion of 0.1 microgram-1.kg-1.min-1 PGE1 plus injection of 1 mg-1.kg-1 lidocaine. Lidocaine was injected two minutes before tracheal extubation. The PGE1 was infused from completion of surgery until five minutes after tracheal extubation. Anaesthesia was maintained with sevoflurane 1.0%-2.5% and nitrous oxide 60%. Heart rate (HR) and blood pressure (BP) were measured before and after tracheal extubation. RESULTS: Lidocaine alone and PGE1-lidocaine combination attenuated the increases in BP and HR observed in the control group: PGE1 alone was effective in attenuating hypertensive response but ineffective for tachycardia. The suppressive effect of the PGE1-lidocaine combination on BP increase was superior to that of each drug alone, and the combined effect on HR increase was similar to that of lidocaine alone. CONCLUSION: The combination of PGE1 infusion and lidocaine is a more effective method of attenuating hypertension and tachycardia associated with tracheal extubation than either drug alone.

Adult↗
PubMed1997

Dose-response of flurbiprofen on postoperative pain and emesis after paediatric strabismus surgery.

PURPOSE: Intravenous flurbiprofen, a non-steroidal antiinflammatory drug (NSAID), has been used recently for postoperative pain relief in adults. The drug is also likely to have antiemetic property. The present study was undertaken to investigate the effect of flurbiprofen on postoperative pain and emesis in children undergoing strabismus surgery, which is well known to produce postoperative nausea and vomiting. METHODS: In a prospective, randomised, controlled clinical trial, 90 children aged 2-11 yr received saline (control), flurbiprofen 0.5 mg.kg-1, or flurbiprofen 1 mg.kg-1. Saline and flurbiprofen were administered i.v. immediately after induction of anaesthesia. Anaesthesia was induced and maintained with sevoflurane and nitrous oxide in oxygen. Postoperative pain was assessed by a blinded observer using an objective pain scale (OPS). No opioids or antiemetics were administered throughout the study. The incidence and frequency of vomiting were compared among groups. RESULTS: Flurbiprofen 1 mg.kg-1 provided lower OPS (highest) scores during the eight hours after surgery and a reduced requirement for postoperative supplementary analgesic (diclofenac suppository) compared with the other two regimens. The two doses of flurbiprofen failed to decrease the incidence and frequency of vomiting. CONCLUSION: These data suggest that preoperative flurbiprofen 1 mg.kg-1 iv is a simple and effective approach to postoperative pain relief but not to the prevention of emesis following paediatric strabismus surgery.

Analgesics↗
PubMed1997

Pectinolytic enzymes from Pseudomonas marginalis MAFF 03-01173.

Two pectinolytic enzymes were purified from the culture broth of Pseudomonas marginalis pv. marginalis MAFF 03-01173 with total 33% recovery of the initial activity. From the substrate specificities against pectin and polygalacturonic acid, the requirement of calcium ion for the enzymatic activity, and the N-terminal sequences, the enzymes were identified as pectin lyase and pectate lyase. The M,s of pectin lyase and pectate lyase were estimated to be 34,000 and 43,000, respectively, by SDS polyacrylamide gel electrophoresis. Both enzymes showed almost the same pH dependent activity curves with the highest activity at pH 8.3

Amino Acid Sequence↗
PubMed1997

ONO-5046, an elastase inhibitor, attenuates endotoxin-induced acute lung injury in rabbits.

Endotoxin causes acute lung injury resembling acute respiratory distress syndrome. Elastase, as well as reactive oxygen species released from activated neutrophils, are thought to play pivotal roles in the pathogenesis of this lung injury. This study investigated whether ONO-5046, a specific elastase inhibitor, can attenuate acute lung injury induced by endotoxin in rabbits. Thirty-two male anesthetized rabbits were randomly assigned to receive one of four treatments (n = 8 for each group): infusion of saline without ONO-5046 treatment (Group S-S), infusion of saline with ONO-5046 (Group S-O), infusion of Escherichia coli endotoxin (100 micrograms/kg over 60 min) without ONO-5046 (Group E-S), and infusion of endotoxin with ONO-5046 (Group E-O). Fifteen minutes before the infusion of endotoxin (Groups E-O and E-S) or saline (Groups S-S and S-O), the animals received a bolus injection of ONO-5046 (10 mg/kg) followed by continuous infusion (10 mg.kg-1.h-1: Groups S-O and E-O) or saline (Groups S-S and E-S). The lungs of the rabbits were ventilated with 40% oxygen. Hemodynamics, peripheral leukocyte and platelet counts, and PaO2 were recorded during the ventilation period (6 h). Lung mechanics, cell fraction of the bronchoalveolar lavage fluid (BALF), activated complement, cytokines, and arachidonic acid metabolite concentrations in the BALF were measured at 6 h. The wet- to dry (W/D)-weight ratio of the lung and albumin concentrations in BALF were analyzed as indices of pulmonary edema. Endotoxin decreased lung compliance and PaO2, and increased the W/D weight ratio, neutrophil counts, and albumin concentration in the BALF. Concentrations of activated complement C5a, interleukin-6, interleukin-8, and thromboxane B2 in the BALF were increased by the infusion of endotoxin. ONO-5046 treatment attenuated these changes. Endotoxin caused extensive morphologic lung damage, which was lessened by ONO-5046. In conclusion, intravenous ONO-5046 pretreatment attenuated endotoxin-induced lung injury in rabbits. This beneficial effect of ONO-5046 may be due, in part, to a reduction in the levels of mediators that activate neutrophils, in addition to the direct inhibitory effect on elastase.

Airway Resistance↗
PubMed1997

Optimal dose of granisetron for prophylaxis against postoperative emesis after gynecological surgery.

UNLABELLED: We previously reported that 20 and 40 microg/kg of granisetron given during anesthesia prevented postoperative emesis with no severe complications. The aim of the current study was to determine the optimal dose of granisetron for the prevention of postoperative nausea and vomiting (PONV) after gynecological surgery. Two hundred female patients (ASA physical status I) were randomly allocated to one of five groups (n = 40 for each): saline (as a control), granisetron 2 microg/kg, granisetron 5 microg/kg, granisetron 10 microg/kg, and granisetron 20 microg/kg. Saline or granisetron was given intravenously immediately after induction of anesthesia. PONV was assessed 24 h after surgery. The percentage of emesis-free patients was significantly greater in the 5- to 20-microg/kg granisetron groups than in the control and 2-microg/kg granisetron groups (18%, 23%, 68%, 78%, and 75% of patients receiving saline or granisetron 2 microg/kg, 5 microg/kg, 10 microg/kg, and 20 microg/kg, respectively). Granisetron doses of 5 microg/kg or larger were also superior to the saline and 2-microg/kg granisetron treatment for the prevention of nausea over the 24-h study period (nausea visual analog scales 24 h after surgery: 49, 41, 18, 16, and 14 mm in the control and granisetron 2 microg/kg, 5 microg/kg, 10 microg/kg, and 20 microg/kg groups, respectively). A smaller proportion of patients received "rescue" antiemetic in the 5-microg/kg or larger granisetron groups than in the control and 2-microg/kg granisetron groups (48%, 40%, 18%, 13%, and 10% of patients in the control and granisetron 2 microg/kg, 5 microg/kg, 10 microg/kg, and 20 microg/kg groups, respectively). The antiemetic effect of granisetron was similar among the groups who received 5-microg/kg or larger doses. In conclusion, we suggest that the optimal dose of granisetron is 5 microg/kg for the prevention of PONV after gynecological surgery. IMPLICATIONS: Nausea and vomiting postoperatively after gynecologic surgery is a significant problem. The authors found that granisetron, a selective antagonist of serotonin, markedly decreases the incidence of postoperative nausea and vomiting at doses of 5 microg/kg or larger.

Adult↗
PubMed1997

Attenuation of cardiovascular responses to tracheal extubation: comparison of verapamil, lidocaine, and verapamil-lidocaine combination.

UNLABELLED: We recently showed that verapamil attenuated hemodynamic responses to tracheal extubation. The aim of the current study was to compare the efficacy of a combination of intravenous (I.V.) verapamil (0.1 mg/kg) and I.V. lidocaine (1 mg/kg) with that of each drug alone in suppressing the cardiovascular changes during tracheal extubation and emergence from anesthesia. One hundred adult patients (ASA physical status I) who were to undergo elective minor surgery were randomly assigned to one of four groups (n = 25 each): Group S = saline plus saline (control), Group V = verapamil 0.1 mg/kg I.V. plus saline, Group L = lidocaine 1 mg/kg I.V. plus saline, and Group V-L = verapamil 0.1 mg/kg I.V. plus lidocaine 1 mg/kg I.V. These medications were given 2 min before tracheal extubation. Anesthesia was maintained with 1.0%-2.0% sevoflurane and 60% nitrous oxide (N2O) in oxygen. Muscle relaxation was achieved with vecuronium, and a residual neuromuscular blockade was reversed with neostigmine 0.05 mg/kg (combined with atropine 0.02 mg/kg). Changes in heart rate (HR) and arterial blood pressure (AP) were measured during and after tracheal extubation. In the control group, the HR and systolic and diastolic AP increased significantly during tracheal extubation. Verapamil, lidocaine, and their combination attenuated the increases in these variables. The beneficial effect was the greatest with the combination of verapamil and lidocaine. These findings suggest that verapamil 0.1 mg/kg and lidocaine 1 mg/kg given I.V. concomitantly 2 min before tracheal extubation is a simple and more effective prophylaxis than verapamil or lidocaine alone for attenuating the cardiovascular changes associated with tracheal extubation. IMPLICATIONS: Tachycardia and hypertension associated with tracheal extubation, which may lead to myocardial ischemia, represent a potential risk for patients with coronary arterial disease. To seek effective pharmacological prophylaxis against these complications, we compared the attenuation of hemodynamic changes among verapamil, lidocaine, and a verapamil/lidocaine combination using ASA physical status I patients and found the combination to be effective.

Adult↗
PubMed1997

Oral clonidine premedication reduces minimum alveolar concentration of sevoflurane for tracheal intubation in children.

BACKGROUND: Sevoflurane is a useful anesthetic for inhalational induction in children because of its low solubility in blood and relatively nonpungent odor. Clonidine has sedative and anxiolytic properties and reduces the requirement for inhalation agents. Nitrous oxide (N2O) also decreases the requirement of inhaled anesthetics, but the effect is variable. The minimum alveolar concentration for tracheal intubation (MAC(TI)) of sevoflurane was assessed with and without N2O and clonidine premedication. METHODS: Seventy-two patients, aged 3-11 yr, were assigned to one of six groups (n = 12 each). They received one of three preanesthetic medications (two groups for each premedication): placebo (control), 2 microg/kg oral clonidine or 4 microg/kg oral clonidine. In one group of each premedication, anesthesia was induced with sevoflurane in oxygen; in the other group, anesthesia was induced with sevoflurane in the presence of 60% N2O. Each concentration of sevoflurane at which tracheal intubation was attempted was predetermined according to Dixon's up-and-down method and held constant for at least 20 min before the trial RESULTS: The MAC(TI) of sevoflurane in the absence of N2O (mean +/- SEM) was 3.2 +/- 0.2%, 2.5 +/- 0.1%, and 1.9 +/- 0.2% in the control, 2-microg/kg clonidine, and 4-microg/kg clonidine groups, respectively. Nitrous oxide (60%) decreased the MAC(TI) of sevoflurane by 26%, 24%, and 27% in the control, 2-microg/kg clonidine, and 4-microg/kg clonidine groups. CONCLUSIONS: Oral clonidine premedication decreased the MAC(TI) of sevoflurane. Nitrous oxide also decreased the MAC(TI). The combination of clonidine and N2O lessened the MAC(TI) of sevoflurane more than did either drug alone.

Administration, Oral↗
PubMed1997

Inhibitory effect of local anaesthetics on reactive oxygen species production by human neutrophils.

BACKGROUND: Reactive oxygen species (ROS) generated from neutrophils accumulated in various major organs are thought to play a pivotal role in the pathogenesis of host auto-injury. Lidocaine has been shown to reduce the injury. We investigated the effect of local anaesthetics (lidocaine, mepivacaine and bupivacaine) on ROS production by neutrophils using an in vitro system. METHODS: We measured the production of superoxide (ferricytochrome c method), hydrogen peroxide (H2O2: scopoletin fluorescence technique), and hydroxyl radical (OH.: ethylene gas method) by neutrophils isolated from human adult volunteers in the absence and presence of lidocaine (2-200 micrograms/mL), mepivacaine (3-300 micrograms/mL), and bupivacaine (3-300 micrograms/mL). We also measured the ROS generation in a cell-free (xanthine-xanthine oxidase) system. RESULTS: Lidocaine and mepivacaine at higher levels significantly decreased the production of ROS by neutrophils. However, these local anaesthetics at clinically relevant blood concentrations had no effect on the levels of ROS. Furthermore, lidocaine and mepivacaine failed to reduce ROS generated by the cell-free system. Bupivacaine did not decrease ROS generation by either generating system. CONCLUSION: In conclusion, in the present in vitro system, only concentrations of lidocaine and mepivacaine 100-fold higher than clinically feasible ones reduced ROS production by human neutrophils. However, the local anaesthetics at clinically relevant blood concentrations had no suppressive effect. Further studies using in vivo systems are required to elucidate the inhibitory effects of local anaesthetics on ROS generation in clinical settings.

Adult↗
PubMed1996

Bifunctional labeling reagent for oligosaccharides to incorporate both chromophore and biotin groups.

We have developed a convenient and effective method for biotinylation of oligosaccharides at their reducing ends. A novel biotin hydrazide having a phenyl group produced the biotin adduct of N-acetyllactosamine (LacNAc) by simple incubation at 90 degrees C for 1 h. Although the biotin adduct was obtained as a mixture of several stereoisomers, one of the isomers, cyclic beta-glycoside, became predominant upon letting the reaction mixture stand in a weakly acidic state (pH 3.5). This conversion may be very advantageous for functional analysis of oligosaccharides because natural N-linked oligosaccharides exist in the cyclic beta form. The limit of detection of labeled LacNAc in reversed-phase chromatography was 330 fmol and showed good linearity in the range from 330 fmol to 261 pmol. When this procedure was applied to complex type and high mannose type N-linked oligosaccharides, the labeled oligosaccharides were easily detected and separated by reversed-phase, gel filtration, and anion exchange chromatographies. Furthermore, these labeled oligosaccharides were able to be immobilized onto the solid phase using avidin-biotin technology and were stable enough to allow the binding assay to be performed repeatedly and under the conditions for in situ exoglycosidase digestion. These results suggest that this derivatization technique might be useful for both separation and functional analysis of oligosaccharides.

Biosensing Techniques↗