Giant Rashba-type spin splitting in bulk BiTeI

There has been increasing interest in phenomena emerging from relativistic electrons in a solid, which have a potential impact on spintronics and magnetoelectrics. One example is the Rashba effect, which lifts the electron-spin degeneracy as a consequence of spin-orbit interaction under broken inversion symmetry. A high-energy-scale Rashba spin splitting is highly desirable for enhancing the coupling between electron spins and electricity relevant for spintronic functions. Here we describe the finding of a huge spin-orbit interaction effect in a polar semiconductor composed of heavy elements, BiTeI, where the bulk carriers are ruled by large Rashba-like spin splitting. The band splitting and its spin polarization obtained by spin- and angle-resolved photoemission spectroscopy are well in accord with relativistic first-principles calculations, confirming that the spin splitting is indeed derived from bulk atomic configurations. Together with the feasibility of carrier-doping control, the giant-Rashba semiconductor BiTeI possesses excellent potential for application to various spin-dependent electronic functions.

Gemcitabine chemoresistance and molecular markers associated with gemcitabine transport and metabolism in human pancreatic cancer cells

To identify predictive molecular markers for gemcitabine resistance, we investigated changes in the expression of four genes associated with gemcitabine transport and metabolism during the development of acquired gemcitabine resistance of pancreatic cancer cell lines. The expression levels of human equilibrative nucleoside transporter-1 (hENT1), deoxycytidine kinase (dCK), RRM1, and RRM2 mRNA were analysed by real-time light cycler-PCR in various subclones during the development of acquired resistance to gemcitabine. Real-time light cycler-PCR demonstrated that the expression levels of either RRM1 or RRM2 progressively increased during the development of gemcitabine resistance. Expression of dCK was slightly increased in cells resistant to lower concentrations of gemcitabine, but was decreased below the undetectable level in higher concentration-resistant subclones. Expression of hENT1 was increased in the development of gemcitabine resistance. As acquired resistance to gemcitabine seems to correlate with the balance of these four factors, we calculated the ratio of hENT1 × dCK/RRM1 × RRM2 gene expression in gemcitabine-resistant subclones. The ratio of gene expression decreased progressively with development of acquired resistance in gemcitabine-resistant subclones. Furthermore, the expression ratio significantly correlated with gemcitabine sensitivity in eight pancreatic cancer cell lines, whereas no single gene expression level correlated with the sensitivity. These results suggest that the sensitivity of pancreatic cancer cells to gemcitabine is determined by the ratio of four factors involved in gemcitabine transport and metabolism. The ratio of the four gene expression levels correlates with acquired gemcitabine-resistance in pancreatic cancer cells, and may be useful as a predictive marker for the efficacy of gemcitabine therapy in pancreatic cancer patients.

A new antifungal antibiotic, trichostatin

A new antibiotic, trichostatin, was isolated from the metabolites of strains of Streptomyces hygroscopicus. It is active against trichophytons and some fungi. The structure was determined to be a derivative of a primary hydroxamic acid by chemical and spectroscopic evidences.

Color Doppler evaluation of valvular regurgitation in normal subjects

To determine prospectively the prevalence of mitral, aortic, tricuspid, and pulmonary regurgitation in normal persons, 211 consecutive, apparently healthy volunteers were examined with a color Doppler flow imaging system. The subjects were divided into five age groups (group 1, 6-9 years old; group 2, 10-19 years old, group 3, 20-29 years old, group 4, 30-39 years old, and group 5, 40-49 years old). The prevalence rate of mitral regurgitation in the normal subjects was 38-45% in each group. The mitral regurgitant jets came from the posteromedial commissure in all but two subjects. No aortic regurgitant flow signals were detected in the normal subjects. Tricuspid regurgitation was detected in 15-77% in each group, and pulmonary regurgitation was detected in 28-88%. Regarding the tricuspid and pulmonic valves, the prevalence rate of regurgitation is age dependent (p less than 0.01) and tends toward the lower rate in groups over the age of 30 years. The tricuspid and pulmonary regurgitant jets came from the center of the coaptation of each valve. The area of the regurgitant jet signals in normal persons was significantly smaller (p less than 0.001) than that obtained from patients with organic valve disease. Our study shows that in a large proportion of normal persons under the age of 50 years color Doppler echocardiography permits recording of regurgitant signals behind all valves except the aortic. In conclusion, one should be aware of the existence and characteristics of regurgitation in normal persons when evaluating valvular regurgitation by Doppler techniques.

Adjuvant activity of diesel-exhaust particulates for the production of IgE antibody in mice

The prevalence rate of allergic rhinitis caused by pollen has strikingly increased in Japan in the last three decades. The number of diesel cars in use has also rapidly increased in the country. This fact urged us to study the effects of particulates emitted from diesel cars on the production of IgE antibody. The primary IgE antibody responses in mice immunized with intraperitoneal injection of ovalbumin (OA) mixed with diesel-exhaust particulates (DEP) were higher than those in the animals immunized with OA alone. This effect of DEP on the production of IgE antibody in mice was also demonstrated when mice were immunized with repeated injections of dinitrophenylated-OA. In addition, persistent IgE-antibody response to major allergen of Japanese cedar pollen (JCPA), a most common pollen causing allergic rhinitis in Japan, was observed in mice immunized with JCPA mixed with DEP but not in the animals immunized with JCPA alone. The results do indicate that the adjuvant activity of DEP can not be excluded as a possible cause of the associated change in the number of diesel cars and allergic rhinitis caused by pollen in Japan.

Regulation of POU genes by castor and hunchback establishes layered compartments in the Drosophila CNS

POU transcription factors participate in cell-identity decisions during nervous system development, yet little is known about the regulatory networks controlling their expression. We report all known Drosophila POU genes require castor (cas) for correct CNS expression. drifter and I-POU depend on cas for full expression, whereas pdm-1 and pdm-2 are negatively regulated. cas encodes a zinc finger protein that shares DNA-binding specificity with another pdm repressor: the gap segmentation gene regulator Hunchback (Hb). Our studies reveal that the embryonic CNS contains sequentially generated neuroblast sublineages that can be distinguished by their expression of either Hb, Pdm-1, or Cas. Hb and Cas may directly silence pdm expression in early and late developing sublineages, given that pdm-1 cis-regulatory DNA contains >=32 Hb/Cas-binding sites and its enhancer(s) are ectopically activated in cas- neuroblasts. In addition, the targeted misexpression of Cas in all neuroblast lineages reduces Pdm-1 expression without altering Hb expression. By ensuring correct POU gene expression boundaries, hb and cas maintain temporal subdivisions in the cell-identity circuitry controlling CNS development.

Diesel-exhaust particulates inoculated by the intranasal route have an adjuvant activity for IgE production in mice

Our previous study indicated that the IgE antibody responses in mice immunized with intraperitoneal injection of the antigens mixed with diesel-exhaust particulates (DEP) were higher than those in the animals immunized with the antigens alone. We examined the adjuvant activity of DEP inoculated by the intranasal route, i.e., the natural entrance of DEP. In 3-week interval immunization, the IgE antibody responses in mice immunized with intranasal inoculation of ovalbumin (OA) mixed with DEP were higher than responses in the animals immunized with OA alone. DEP had an adjuvant activity for anti-OA IgE antibody production, even in a small dose such as 1 micrograms administered with a 3-week interval. Also in 1-week interval immunization, the enhancing effect of DEP on anti-OA IgE antibody production was demonstrated when mice were immunized with intranasal inoculation of OA and DEP. The possibility cannot be excluded that DEP, which are kept buoyant in the environmental atmosphere of urban districts, may exert an adjuvant activity for IgE antibody production after being inhaled into the human body and have some relation to the mechanism of the outbreak of allergic rhinitis caused by pollens in Japan.

Mesp2 initiates somite segmentation through the Notch signalling pathway

The Notch-signalling pathway is important in establishing metameric pattern during somitogenesis. In mice, the lack of either of two molecules involved in the Notch-signalling pathway, Mesp2 or presenilin-1 (Ps1), results in contrasting phenotypes: caudalized versus rostralized vertebra. Here we adopt a genetic approach to analyse the molecular mechanism underlying the establishment of rostro-caudal polarity in somites. By focusing on the fact that expression of a Notch ligand, Dll1, is important for prefiguring somite identity, we found that Mesp2 initiates establishment of rostro-caudal polarity by controlling two Notch-signalling pathways. Initially, Mesp2 activates a Ps1-independent Notch-signalling cascade to suppress Dll1 expression and specify the rostral half of the somite. Ps1-mediated Notch-signalling is required to induce Dll1 expression in the caudal half of the somite. Therefore, Mesp2- and Ps1-dependent activation of Notch-signalling pathways might differentially regulate Dll1 expression, resulting in the establishment of the rostro-caudal polarity of somites.

Amyotrophic lateral sclerosis: T2 shortening in motor cortex at MR imaging

PURPOSE

To determine whether decreased signal intensity of the motor cortex (T2 shortening) at magnetic resonance (MR) imaging is a useful finding for supporting the diagnosis of amyotrophic lateral sclerosis (ALS).

MATERIALS AND METHODS

High-field-strength (1.5-T) MR images of 15 patients (seven men and eight women, aged 28-80 years) and 49 neurologically normal age-matched control patients were examined for T2 shortening in the motor cortex. In addition, brains of patients with ALS were examined at autopsy.

RESULTS

The MR images of 14 of the 15 patients showed T2 shortening in precentral cortices, while the images of all but one of the control patients showed no such finding. In three of eight brains at autopsy, sections from the precentral cortex showed sparsely distributed, intensely stained astrocytes and macrophages.

CONCLUSION

Abnormal iron deposition associated with the degenerative process could be the source of T2 shortening, which is a useful MR imaging finding in the diagnosis of ALS.

Studies of antidromically identified neurosecretory cells of the hypothalamus by intracellular and extracellular recordings

1. Neurosecretory neurones in supraoptic (SON) and paraventricular (PVN) nuclei of the hypothalamus of cats, anaesthetized with chloralose, and dogs, anaesthetized with Nembutal, were studied. These neurosecretory neurones were identified by action potentials evoked antidromically following stimulation of the posterior lobe of the pituitary gland. Reactions of 158 such neurones in cats and 228 in dogs were analysed.2. The latencies of antidromic potentials evoked in neurosecretory neurones by posterior lobe stimulation were between 10 and 22 msec for SON and between 14 and 28 msec for PVN cells. Approximate speed of conduction in the axons was 0.4-0.9 m/sec. The absolute refractory period for the soma-dendritic (SD) spike was 5-10 msec. These cells followed repetitive stimulation up to a rate of 100/sec.A notch was generally present on the rising phase of antidromic potentials and when the antidromically conducted signal fell in the relative refractory period of the preceding response, a complete separation between this first small A-spike and later large B-spikes, probably soma-dendritic spike, frequently occurred. Thus, two responses, a small and a large, sometimes appeared with more than 10 msec intervening. When the second antidromic response fell in the absolute refractory period of the first, the B-spike was blocked and only the A-spike appeared.3. Intracellular recordings from neurosecretory cells, mainly from SON in the dog, showed that these neurones possess resting membrane potentials of 50-80 mV, and action potentials of the same magnitude. In spontaneously firing neurosecretory cells separate A- and B-spikes also occurred and could be recorded intracellularly.4. Neurosecretory cells were excited by current injected intracellularly through a micro-electrode. The rheobase was 1-10 nA. A low intensity of stimulation only induced a small A-spike, but as the current was increased the full sized spike was evoked. Application of suprathreshold depolarizing current produced repetitive discharges. The intervals between spikes shortened with an increase in applied current intensity.5. There were a few neurones excited by stimulation of the posterior pituitary whose potentials did not meet the adopted criteria of antidromic potentials. These units were not classified as neurosecretory cells. The characteristics of cells giving the atypical ;antidromic potentials' were: the neurones discharged repetitively to antidromic stimulation, but with fluctuating and very long latencies.6. Neurosecretory cells in both SON and PVN were orthodromically excited by single pulse stimulations of the septal area, mid-brain reticular formation (RF), central gray, anterior commissure and hippocampus. The orthodromic responses generally consisted of two to three spikes with latencies of 10-30 msec. Excitation was followed by an inhibition, of ;spontaneous' discharges as well as of subsequent antidromic excitation, lasting 100-500 msec. Intracellular recordings from neurosecretory cells showed that stimulations of the septal area and RF produced action potentials or EPSPs of short duration followed by long lasting IPSPs. Hyperpolarization was always longer than the preceding EPSP, and its duration was generally 80 msec. Large IPSPs of 20 mV could be recorded occasionally.7. Antidromic excitation of neurosecretory cells by stimulation of the posterior pituitary was followed by the inhibition of ;spontaneous' discharges of the cells. This inhibition usually lasted for 100 msec. A corresponding IPSP was recorded during this inhibitory phase. These findings indicate the existence of recurrent collaterals in neurosecretory cells.8. This conclusion that recurrent collaterals exist was also supported by other evidence, namely, that certain neurones were found in the SON and PVN which responded to a single pulse antidromic stimulation of the posterior pituitary with five to seven discharges at a rate of between 500 and 800/sec. Weaker stimuli produced fewer spikes. Such cells resembled in their behaviour ;Renshaw cells' of the spinal cord. RF stimulation had an inhibitory effect on some of these neurones and an excitatory effect on others.9. Neurosecretory cells in the SON and PVN were excited by osmotic stimulation. Other neurones in close proximity were also found to be osmosensitive but they were either interneurones or neurosecretory cells whose axons ended in areas other than the posterior pituitary since they were not antidromically excitable.

Reciprocal and non-reciprocal action of the vagal and sympathetic nerves innervating the heart

Simultaneous recordings were made from vagal and sympathetic fibers innervating the heart in dogs anesthetized with chloralose. Reciprocal relationship between the two autonomic nerves was clearly seen in the baroreceptor reflex. Stimulation of chemoreceptors, however, evoked non-reciprocal responses of the two nerves; at the onset of the chemoreceptor reflex cardiac vagal and sympathetic discharges both increased, then, as baroreceptors became excited due to a pressor response, sympathetic nerve activity suddenly decreased while vagal discharges remained high, indicating the appearance of the reciprocal action typifying the baroreceptor reflex. Decrease in ventilatory volume and a slight increase in end-expired CO2 level augmented greatly both vagal and sympathetic discharges. As the phrenic-locked activity of the two nerves (i.e. the activity in vagus nerve occurs only in the absence of phrenic bursts while sympathetic discharges increase with phrenic bursts) increased, the alternate discharges between the two nerves became more conspicuous and the heart rate fluctuated with the respiratory (phrenic) rhythm. Thus, strong reciprocity between vagus and sympathetic can result in an oscillatory heart rate. When ventilatory volume was increased, both nerve activities decreased below control level. Mild hypoxia had similar effects to hypercapnia though changes in nerve activity were greater. When coactivation of vagal and sympathetic nerve was produced in reflex action, changes in vagal discharges occurred earlier and faster than in the sympathetic fibers. The magnitude of change in vagus activity was also far greater. The elimination of afferents in the vagi, the aortic and sinus nerves reduced cardiac vagal activity greatly. However, discharges were still present and occurred between phrenic bursts, indicating that the vagal "tone" is maintained centrally as well as peripherally by input from receptors in the cardiovascular system. The physiological significance of reciprocal and non-reciprocal control of vagal and sympathetic nerves innervating the heart was discussed.

Effect of cardiac vagal and sympathetic nerve activity on heart rate in rhythmic fluctuations

Beat-to-beat changes observed in cardiac vagal and sympathetic nerve activity and their effects on cardiac cycle length were studied during slow wave blood pressure and heart rate fluctuations (third order rhythm) and during respiratory sinus arrhythmia. Recordings were made from both nerves simultaneously in chloralose anesthetized and artificially ventilated dogs. During slow wave fluctuations in heart rate, a linear relationship was found to exist between the number of spikes per pulse interval recorded from vagal and sympathetic nerves and the length of pulse intervals. During respiratory sinus arrhythmia the time course of rhythmic changes in nerve activity and in cardiac cycle length was analyzed. Comparison of time courses indicated that vagal discharges affected the timing of not the following beat, but the one after; while the sympathetic effect was further delayed, affecting the third beat after the discharge. Baroreceptor stimulation, which resulted in lengthening the cardiac cycle, shifted this relationship by one cycle, i.e. vagal discharges affecting the occurrence of the following beat, while sympathetic discharges affecting the beat after. These results provide evidence for the conclusion that in dogs both vagal and sympathetic nerve activity contribute to the control of cardiac cycle length, however, with different time relations and effectiveness.

Novel antiarthritic agents with 1,2-isothiazolidine-1,1-dioxide (gamma-sultam) skeleton: cytokine suppressive dual inhibitors of cyclooxygenase-2 and 5-lipoxygenase

Various 1,2-isothiazolidine-1,1-dioxide (gamma-sultam) derivatives containing an antioxidant moiety, 2,6-di-tert-butylphenol substituent, were prepared. Some compounds, which have a lower alkyl group at the 2-position of the gamma-sultam skeleton, showed potent inhibitory effects on both cyclooxygenase (COX)-2 and 5-lipoxygenase (5-LO), as well as production of interleukin (IL)-1 in in vitro assays. They also proved to be effective in several animal arthritic models without any ulcerogenic activities. Among these compounds, (E)-(5)-(3,5-di-tert-butyl-4-hydroxybenzylidene)-2-ethyl-1, 2-isothiazolidine-1,1-dioxide (S-2474) was selected as an antiarthritic drug candidate and is now under clinical trials. The structure-activity relationships (SAR) examined and some pharmacological evaluations are described.

High-performance liquid chromatographic separation of carbohydrates on graphitized carbon columns

Graphitized carbon columns (GCC) for high-performance liquid chromatography are relatively new and have a unique ability to resolve isomeric and closely related compounds. The retention mechanism of carbohydrates on GCC is mainly based on adsorption and the flat surface of GCC packings brings about unique selectivity, but also includes hydrophobic interactions. The chromatographic behaviour of monosaccharides, disaccharides, cyclodextrins (CDs), branched CDs, oligosaccharide alditols, chito-oligosaccharides, N-linked oligosaccharides and glycopeptides has been studied, and it has become apparent that the elution patterns are based on the size and planarity of the molecule (position and configuration of linkage).

Age-related valvular regurgitation: a study by pulsed Doppler echocardiography

To assess the prevalence of valvular regurgitation in the aged, we studied 176 apparently healthy volunteers with no history or physical evidence of cardiac abnormality. Their ages ranged from 40 to 90 (66 +/- 14, mean +/- SD) years. We examined these subjects by pulsed Doppler echocardiography combined with two-dimensional echocardiography to determine the prevalence of valvular regurgitation. Regurgitation began to appear in subjects in their fifties, increasing in prevalence with advancing age (r = .81, p less than .001), and was documented in all over age 80. Similarly, regurgitation involving more than one valve appeared in those 60 years and older, and was very common (89%) in subjects in their eighties. With each type of valvular regurgitation, the prevalence of each type of regurgitation increased with aging, but this tendency was most prominent for aortic regurgitation. We conclude that (1) single or multivalvular regurgitation as detected by pulsed Doppler echocardiography is very common in the aged and may be considered a normal finding in the absence of other evidence of heart disease, and (2) the high prevalence of regurgitation in the aged must be taken into account when Doppler examinations are being performed.

A series of novel mutants of Arabidopsis thaliana that are defective in the formation of continuous vascular network: calling the auxin signal flow canalization hypothesis into question

For the genetic analysis of molecular mechanisms underlying temporal and spatial regulation of vascular pattern formation, we isolated mutants of Arabidopsis thaliana that are impaired in vascular patterning. Microscopic examination of the cotyledonary venation of 3,400 M(3) lines led to the identification of 12 mutant lines. Genetic analysis of 8 of these mutant lines indicated that vein pattern formation in these lines resulted from monogenic recessive mutations in 7 different genes, designated VAN1 through VAN7. Mutations in VAN1 through VAN6 genes caused fragmentation (disconnection or partial loss) of lateral veins of the cotyledon and tertiary veins of the rosette leaf whereas they were less injurious to the formation of major veins. Detailed characterization of the van3 mutant using pAthb8::GUS and pTED3::GUS, as molecular markers for the early stage of vascular tissue formation showed that the provascular tissue of the cotyledonary lateral veins was differentiated in fragments during late embryogenesis. These phenotypes of the van mutants are discussed in relation to the auxin signal flow canalization hypothesis and the diffusion-reaction prepattern hypothesis, with the fragility of the continuity in the minor vein formation favoring the latter hypothesis.

Cloning of the Drosophila prospero gene and its expression in ganglion mother cells

The Drosophila central nervous system comprises an enormous diversity of neurons that are originated from neuronal stem cells, neuroblasts. They generate a specific series of ganglion mother cells, each of which is once cleaved into a pair of neurons. Among genes known to control neurogenesis, prospero (pros) was recently identified as a gene required for gene expression specifying properties of some identified neurons. Here we report that pros encodes a nuclear protein containing a homeodomain-like sequence. In neuronal lineages of the central nervous system, pros protein is specifically detected in ganglion mother cells, although their parental neuroblasts have begun expressing a significant level of pros transcripts, suggesting a post-transcriptional control of pros expression. Our results provoke that in neuronal cell differentiation ganglion mother cells might play a pivotal role associating with the pros function.

Human breast cancer tissues contain abundant phosphatidylcholine(36∶1) with high stearoyl-CoA desaturase-1 expression

Breast cancer is the leading cause of cancer and mortality in women worldwide. Recent studies have argued that there is a close relationship between lipid synthesis and cancer progression because some enzymes related to lipid synthesis are overexpressed in breast cancer tissues. However, lipid distribution in breast cancer tissues has not been investigated. We aimed to visualize phosphatidylcholines (PCs) and lysoPCs (LPCs) in human breast cancer tissues by performing matrix assisted laser desorption/ionization-imaging mass spectrometry (MALDI-IMS), which is a novel technique that enables the visualization of molecules comprehensively. Twenty-nine breast tissue samples were obtained during surgery and subjected to MALDI-IMS analysis. We evaluated the heterogeneity of the distribution of PCs and LPCs on the tissues. Three species [PC(32∶1), PC(34∶1), and PC(36∶1)] of PCs with 1 mono-unsaturated fatty acid chain and 1 saturated fatty acid chain (MUFA-PCs) and one [PC(34∶0)] of PCs with 2 saturated fatty acid chains (SFA-PC) were relatively localized in cancerous areas rather than the rest of the sections (named reference area). In addition, the LPCs did not show any biased distribution. The relative amounts of PC(36∶1) compared to PC(36∶0) and that of PC(36∶1) to LPC(18∶0) were significantly higher in the cancerous areas. The protein expression of stearoyl-CoA desaturase-1 (SCD1), which is a synthetic enzyme of MUFA, showed accumulation in the cancerous areas as observed by the results of immunohistochemical staining. The ratios were further analyzed considering the differences in expressions of the estrogen receptor (ER), human epidermal growth factor receptor 2 (HER2), and Ki67. The ratios of the signal intensity of PC(36∶1) to that of PC(36∶0) was higher in the lesions with positive ER expression. The contribution of SCD1 and other enzymes to the formation of the observed phospholipid composition is discussed.

Bone mineral density measured by dual energy x-ray absorptiometry in patients with non-insulin-dependent diabetes mellitus

Because of the previous controversial findings in diabetic patients with older methodologies, we assessed bone mineral density (BMD) in 78 patients (38 males and 40 females) with non-insulin-dependent diabetes mellitus using dual energy x-ray absorptiometry (DEXA). BMD was measured in lumbar vertebrae (L2-4). The BMD of each patient was calculated as the percentage of the mean value (%BMD) obtained from a healthy control group matched for sex and age. The %BMD of the patients with diabetes was about 100% for females and 96% for males, as compared with BMD of normal controls. The %BMD of the patients with diabetes was significantly correlated with body mass index and urinary C peptide level, and inversely correlated with age and duration of diabetes within 20 years. No relationships were found between %BMD and serum calcium, phosphorus, or glycosylated hemoglobin A1C levels. These observations suggest that metabolic abnormalities associated with diabetes mellitus alter the BMD, and that such factors as duration of the disease and deficit in insulin secretion are risk factors for decreased BMD.

High-performance anion-exchange chromatography of homogeneous D-gluco-oligosaccharides and -polysaccharides (polymerization degree greater than or equal to 50) with pulsed amperometric detection

High-performance anion-exchange chromatography under alkaline conditions with pulsed amperometric detection was applied to the analyses of (1----2)-, (1----3)-, (1----4)- and (1----6)-linked homogeneous alpha- or beta-D-gluco-oligosaccharides and -polysaccharides up to a degree of polymerization (DP) of greater than or equal to 50. Each series of homogeneous D-gluco-oligomers and -polymers showed a linear relationship between log k' and DP in isocratic elution using 150 mM sodium hydroxide solution containing 100 mM sodium acetate as the eluent. An effective separation of individual members of an homologous series of linear glucans was achieved using gradient elution, accomplished by maintaining the sodium hydroxide concentration at 150 mM and increasing the sodium acetate concentration during the analysis. The detector response per HCOH group in D-gluco-oligomers (DP 2-7) was almost the same.