Epigallocatechin-3-gallate increases intracellular [Ca2+] in U87 cells mainly by influx of extracellular Ca2+ and partly by release of intracellular stores

Green tea has been receiving considerable attention as a possible preventive agent against cancer and cardiovascular disease. Epigallocatechin-3-gallate (EGCG) is a major polyphenol component of green tea. Using digital calcium imaging and an assay for [3H]-inositol phosphates, we determined whether EGCG increases intracellular [Ca2+] ([Ca2+]i) in non-excitable human astrocytoma U87 cells. EGCG induced concentration-dependent increases in [Ca2+]i. The EGCG-induced [Ca2+]i increases were reduced to 20.9% of control by removal of extracellular Ca2+. The increases were also inhibited markedly by treatment with the non-specific Ca2+ channel inhibitors cobalt (3 mM) for 3 min and lanthanum (1 mM) for 5 min. The increases were not significantly inhibited by treatment for 10 min with the L-type Ca2+ channel blocker nifedipine (100 nM). Treatment with the inhibitor of endoplasmic reticulum Ca2+-ATPase thapsigargin (1 micro M) also significantly inhibited the EGCG-induced [Ca2+]i increases. Treatment for 15 min with the phospholipase C (PLC) inhibitor neomycin (300 micro M) attenuated the increases significantly, while the tyrosine kinase inhibitor genistein (30 micro M) had no effect. EGCG increased [3H]-inositol phosphates formation via PLC activation. Treatment for 10 min with mefenamic acid (100 micro M) and flufenamic acid (100 micro M), derivatives of diphenylamine-2-carboxylate, blocked the EGCG-induced [Ca2+]i increase in non-treated and thapsigargin-treated cells but indomethacin (100 micro M) did not affect the increases. Collectively, these data suggest that EGCG increases [Ca2+]i in non-excitable U87 cells mainly by eliciting influx of extracellular Ca2+ and partly by mobilizing intracellular Ca2+ stores by PLC activation. The EGCG-induced [Ca2+]i influx is mediated mainly through channels sensitive to diphenylamine-2-carboxylate derivatives.

Endogenous somatostatin receptors mobilize calcium from inositol 1,4,5-trisphosphate-sensitive stores in NG108-15 cells

Somatostatin receptors are members of the G-protein-coupled receptor superfamily and exert their principal effects by coupling to inhibitory G-proteins. We used fura-2-based digital calcium imaging and assayed for [3H]inositol phosphates (IPs) to study the effects of somatostatin on intracellular calcium signaling in neuroblastomaxglioma NG108-15 cells. Both somatostatin-14 and octreotide induced concentration-dependent increases in intracellular Ca(2+) concentration ([Ca(2+)](i)). Thirty-four percent of the cells responded to treatment with 100 nM somatostatin-14. Somatostatin-induced responses were not blocked by the removal of extracellular calcium; instead, they were abolished by pretreatment with 100 nM thapsigargin, an agent that depletes and prevents refilling of intracellular Ca(2+) stores. Pretreatment with the inositol 1,4,5-trisphosphate (IP(3)) receptor antagonist xestospongin C (10 microM) for 20 min inhibited markedly the somatostatin-induced response. Somatostatin (100 nM) increased [3H]IPs formation. U73122 (1 microM), an inhibitor of phospholipase C (PLC), completely blocked the somatostatin-induced [Ca(2+)](i) increases and the formation of [3H]IPs. Pretreatment with pertussis toxin (PTX, 200 ng/ml) for 24 h blocked the somatostatin-induced responses. Thus, we conclude that activation of endogenous somatostatin receptors in NG108-15 cells induces the release of calcium from IP(3)-sensitive intracellular stores through PTX-sensitive G-protein-coupled PLC.

Protective effects of epicatechin against the toxic effects of streptozotocin on rat pancreatic islets: in vivo and in vitro

INTRODUCTION

Green tea catechins have diverse pharmacological effects such as anticarcinogenic and antioxidant activities.

AIM

To study the protective effects of green tea (-)-epicatechin (EC) against the toxic effects of streptozotocin (STZ), a selective beta cell toxin, on pancreatic islets in vivo and in vitro.

METHODOLOGY

Rats were randomly divided into four groups: control, EC (30 mg/kg)-treated, STZ (60 mg/kg)-treated, and EC plus STZ (same doses; EC+STZ)-treated rats. EC was administered twice a day for 6 days, and a single injection of STZ was used. In EC+STZ-treated rats, EC was administered 6 hours prior to STZ since posttreatment with EC had no beneficial effects on fully developed diabetes in our unpublished study. Insulin and insulin mRNA were detected by immunohistochemical analysis and in situ hybridization, respectively, and physiologic parameters including blood glucose concentration were measured daily. Following isolation of the islets, insulin release, nitrite levels, and islet morphology were observed in the four groups: control, EC (0.8 mM)-treated, STZ (5 mM)-treated, and EC+STZ (same doses)-treated islets.

RESULTS

In EC+STZ-treated rats, hyperglycemia and weight loss were not observed and islet morphology was well preserved compared with STZ-treated rats. Compared with STZ treatment alone, insulin release was increased and nitrite production was decreased in EC+STZ-treated islets.

CONCLUSION

EC appears to be helpful in protecting pancreatic islets against exposure to STZ in both in vivo and in vitro systems.

Site-specific localization of protein kinase C isoforms in rat pancreas

BACKGROUND

Protein kinase C (PKC), a major signal-transducing enzyme, is recognized to play an important role in the regulation of pancreatic exocrine and endocrine secretion, and yet the distribution of PKC isoforms in rat pancreas has remained unclarified.

AIM OF THE STUDY

We examined the precise localization of PKC isoforms to elucidate the role of PKC in the normal rat pancreas.

METHODS

Male Sprague-Dawley rats were used throughout the experiment. For Western blot analysis, the islet of Langerhans and the acinar tissue were separated by the collagenase digestion method. Also, the whole pancreas was taken out and immunohistochemistry performed.

RESULTS

According to Western blot analysis, PKC-alpha, -gamma, -delta, -epsilon, -zeta, and -lambda were detected in both acinar and islet cells while PKC-beta II were observed exclusively in the islet. PKC-beta I was not observed. On immunohistochemistry, the immunoreactivities of PKC isoforms were observed as follows: PKC-alpha, weakly in some endocrine cells and ductal epithelium; PKC-beta II, mainly in the islet center; PKC-gamma, in the islet, intrapancreatic ganglia and ductal epithelium; PKC-delta, in the islet periphery, weakly in some acinar cells and ductal epithelium; PKC-epsilon, strongly in the islet, acinar cell and ductal epithelium; PKC-zeta, in the islet, acinar cell and ductal epithelium; PKC-lambda in some endocrine cells and ductal epithelium.

CONCLUSION

These results suggest that the intrapancreatic site-specific existence of PKC isoforms may regulate pancreatic exocrine and endocrine functions via a PKC-mediated signal transduction.

Direct inhibition of the cloned Kv1.5 channel by AG-1478, a tyrosine kinase inhibitor

The action of tyrphostin AG-1478, a potent protein tyrosine kinase (PTK) inhibitor, on rat brain Kv1.5 channels (Kv1.5) stably expressed in Chinese hamster ovary cells was investigated using the whole cell patch-clamp technique. AG-1478 rapidly and reversibly inhibited Kv1.5 currents at 50 mV in a concentration-dependent manner with an IC50 of 9.82 microM. AG-1478 accelerated the decay rate of inactivation of Kv1.5 currents without modifying the kinetics of current activation. Pretreatment with the structurally dissimilar PTK inhibitors (genistein and lavendustin A) had no effect on the AG-1478-induced inhibition of Kv1.5 and did not modify the AG-1478-induced current kinetics. The rate constants for binding and unbinding of AG-1478 were 1.46 microM(-1) x s(-1) and 10.19 s(-1), respectively. The AG-1478-induced inhibition of Kv1.5 channels was voltage dependent, with a steep increase over the voltage range of channel opening. However, the inhibition exhibited voltage independence over the voltage range in which channels are fully activated. AG-1478 produced no significant effect on the steady-state activation or inactivation curves. AG-1478 slowed the deactivation time course, resulting in a tail crossover phenomenon. Inhibition of Kv1.5 by AG-1478 was use dependent. The present results suggest that AG-1478 acts directly on Kv1.5 currents as an open-channel blocker and independently of the effects of AG-1478 on PTK activity.

Effect of ethanol on spontaneous phasic contractions of cat gastric smooth muscle

BACKGROUND

Ethanol is generally believed to inhibit extracellular Ca2+ influx, thereby inhibiting gastric muscle contraction. Recently, we observed that verapamil inhibited only the amplitude of spontaneous phasic contractions, whereas ethanol inhibited both amplitude and frequency. In our objective to investigate the mechanism of ethanol's inhibition of gastric motility, the involvement of various protein kinases in ethanol-inhibited spontaneous phasic contractions of the stomach muscle strips was tested.

METHODS

Circular muscle strips (2.0 x 0.2 cm) were prepared from the corpus of cat stomach in order to measure isometric contraction in a chamber filled with Krebs-Ringer solution (pH 7.4, temperature 36 degrees C) bubbled with 5% CO2 in O2.

RESULTS

Spontaneous phasic contraction was not affected by various receptor antagonists (I microM atropine, 1 microM hexamethonium, 1 microM phentolamine and 1 microM propranolol) or 1 microM tetrodotoxin. EGTA and verapamil dose-dependently inhibited only the amplitude of spontaneous phasic contractions and not the frequency. Ethanol dose-dependently inhibited both the amplitude and frequency of phasic contractions. The amplitude and frequency of spontaneous phasic contractions were significantly inhibited by protein kinase C and tyrosine kinase inhibitors. However, neither protein kinase C activator nor various phosphatase inhibitors blocked the inhibitory effect of ethanol.

CONCLUSIONS

Ethanol appears to inhibit spontaneous phasic contractions by a mechanism other than the inhibition of protein kinase C or tyrosine kinase or the inhibition of extracellular Ca2+ influx.

Flux enhancement with gas injection in crossflow ultrafiltration of oily wastewater

The gas injection technique was introduced to achieve flux improvement in cross-flow ultrafiltration of oil emulsion. By the nitrogen gas injection, homogeneous liquid phase oil/water emulsion was changed to heterogeneous gas- liquid phase. The injected gas causes positive effect of promoting turbulence, but it also has negative effect of decreasing the effective membrane area due to the partial occupation of membrane pores by bubbles. The efficiency of the gas injection was found out to be dependent on bubble fractions in the mixture: at sufficient bubble fractions the higher flux was observed. but at lower bubble fractions the flux rather decreased compared with that without gas injection. An attempt was made to explain the mechanisms for the dual aspects of gas injection. Turbulence dampening effect was also observed when the dependence of mass transfer coefficient on cross-flow rate was investigated with gas injection.

Improvement of tagatose conversion rate by genetic evolution of thermostable galactose isomerase

To enhance the isomerization rate of galactose into tagatose, a thermostable galactose isomerase, which was isolated from bacteria growing in a hot spring, was genetically improved using the error-prone PCR method. From 500 mutant clones, a clone showing improved conversion activity was selected. The sequence of the selected clone had five amino acid changes: His(228)-->Asp, Gly(384)-->Asp, Ser(393)-->Thr, Lys(428)-->Asn and Asp(475)-->Lys. The improved galactose isomerase had an 11-fold higher reaction rate than the original.

Attenuation of Zn2+ neurotoxicity by aspirin: role of N-type Ca2+ channel and the carboxyl acid group

Synaptically released Zn2+ ions enter into neurons primarily through voltage-gated Ca2+ channels (VGCC) or N-methyl-d-aspartate (NMDA) receptors, which can mediate pathological neuronal death. We studied the possibility (and underlying mechanisms) that aspirin, known to prevent NMDA neurotoxicity, would also attenuate Zn2+ neurotoxicity. Administration of 3 to 10 mM aspirin, in cortical cell cultures, attenuated the evolution of neuronal death following exposure to 300 microM Zn2+ for 30 min. This neuroprotective effect of aspirin was attributable to the prevention of Zn2+ ion entry. Aspirin interfered with inward currents and an increase in [Ca2+]i through VGCC and selective binding of omega-conotoxin, sensitive to N-type Ca2+ channel. The omega-conotoxins GVIA or MVIIC, the selective inhibitors of N-type Ca2+ channels, attenuated Zn2+ neurotoxicity. Aspirin derivatives lacking the carboxyl acid group did not reduce Zn2+ neurotoxicity. The present findings suggest that aspirin prevents Zn2+-mediated neuronal death by interfering with VGCC, and its action specifically requires the carboxyl acid group.

Neoplastic transformation and tumorigenesis associated with overexpression of phospholipase D isozymes in cultured murine fibroblasts

Phospholipase D (PLD) has been suggested to play an important role in a variety of cellular functions. PLD activity has been shown to be significantly elevated in many tumours and transformed cells, suggesting the possibility that PLD might be involved in tumorigenesis. In this study, we have established stable cell lines overexpressing PLD1 and PLD2 from fibroblast cells. These cells, but not control cells, showed altered growth properties and anchorage-independent growth in soft agar. Both PLD1 and PLD2 also induced an up-regulation of the activity of matrix metalloprotease-9 as detected by zymograms. Furthermore, both PLD1 and PLD2 transformants, but not vector-transfectants, induced undifferentiated sarcoma when transplanted into nude mice. Both PLD1- and PLD2-mediated cell cycle distributions in stable cell lines revealed an increased fraction of cells in the S phase compared with control cells. Interestingly, the level of cyclin D3 protein, known as an activator of G(1) to S phase transition in the cell cycle, was aberrantly high in cells overexpressing PLD1 and PLD2 compared with control cells. These results suggest that overexpression of PLD isozymes may play an important role in neoplastic transformation.

Effects of norfluoxetine, the major metabolite of fluoxetine, on the cloned neuronal potassium channel Kv3.1

The effects of fluoxetine and its major metabolite, norfluoxetine, were studied using the patch-clamp technique on the cloned neuronal rat K(+) channel Kv3.1, expressed in Chinese hamster ovary cells. In whole-cell recordings, fluoxetine and norfluoxetine inhibited Kv3.1 currents in a reversible concentration-dependent manner, with an IC(50) value and a Hill coefficient of 13.11+/-0.91 microM and 1.33+/-0.08 for fluoxetine and 0.80+/-0.06 microM and 1.65+/-0.08 for norfluoxetine at +40 mV, respectively. In inside-out patches, norfluoxetine applied to the cytoplasmic surface inhibited Kv3.1 with an IC(50) value of 0.19+/-0.01 microM. The inhibition of Kv3.1 currents by both drugs was characterized by an acceleration in the apparent rate of current decay, without modification of the activation time course and with relatively fewer effects on peak amplitude. The degree of inhibition of Kv3.1 by norfluoxetine was voltage-dependent. The inhibition increased steeply between 0 and +30 mV, which corresponded with the voltage range for channel opening. In the voltage range positive to +30 mV, inhibition displayed a weak voltage dependence, consistent with an electrical distance delta of 0.31+/-0.05. The association (k(+1)) and dissociation (k(-1)) rate constants for norfluoxetine-induced inhibition of Kv3.1 were 21.70+/-3.39 microM(-1) s(-1) and 14.68+/-3.94 s(-1), respectively. The theoretical K(D) value derived by k(-1)/k(+1) yielded 0.68 microM. Norfluoxetine did not affect the ion selectivity of Kv3.1. The reversal potential under control conditions was about -85 mV and was not affected by norfluoxetine. Norfluoxetine slowed the deactivation time course, resulting in a tail crossover phenomenon when the tail currents, recorded in the presence and absence of norfluoxetine, were superimposed. The voltage dependence of steady-state inactivation was not changed by the drug. Norfluoxetine produced use-dependent inhibition of Kv3.1 at a frequency of 1 Hz and slowed the recovery from inactivation. It is concluded that at clinically relevant concentrations, both fluoxetine and its major metabolite norfluoxetine inhibit Kv3.1, and that norfluoxetine directly inhibits Kv3.1 as an open channel blocker.

Effects of (-)-epigallocatechin-3-gallate, the main component of green tea, on the cloned rat brain Kv1.5 potassium channels

The interaction of (-)-epigallocatechin-3-gallate (EGCG), the main component of green tea (Camellia sinensis), with rat brain Kv1.5 channels (rKv1.5) stably expressed in Chinese hamster ovary (CHO) cells was investigated using the whole-cell patch-clamp technique. EGCG inhibited rKv1.5 currents at +50 mV in a concentration-dependent manner, with an IC50 of 101.2+/-6.2 microM. Pretreatment with protein tyrosine kinase (PTK) inhibitors (10 microM genistein, 100 microM AG1296), a tyrosine phosphatase inhibitor (500 microM sodium orthovanadate), or a protein kinase C (PKC) inhibitor (10 microM chelerythrine) did not block the inhibitory effect of EGCG on rKv1.5. The inhibition of rKv1.5 by EGCG displayed voltage-independence over the full activation voltage range positive to +10 mV. EGCG had no effect on the midpoint potential or the slope factor for steady-state activation and inactivation. EGCG did not affect the ion selectivity of rKv1.5. The activation (at +50 mV) kinetics was significantly slowed by EGCG. During repolarization (at -40 mV), EGCG also slowed the deactivation of the tail currents, resulting in a crossover phenomenon. Reversal of inhibition was detected by the application of repetitive depolarizing pulses and of identical double pulses, especially during the early part of the activating pulse, in the presence of EGCG. EGCG-induced inhibition of rKv1.5 showed identical affinity between EGCG and the multiple closed states of rKv1.5. These results suggest that EGCG interacts directly with rKv1.5 channels. Furthermore, by analyzing the kinetics of the interaction between EGCG and rKv1.5, we conclude that the inhibition of rKv1.5 channels by EGCG includes at least two effects: EGCG preferentially binds to the channel in the closed state, and blocks the channel by pore occlusion while depolarization is maintained.

Expression and regulation of phospholipase D during neuronal differentiation of PC12 cells

To assess a possible role for phospholipase D (PLD) in PC12 cell signal transduction and differentiation, we have investigated the expression of PLD in PC12 cells and found that the differentiation factor, nerve growth factor (NGF) increased PLD1 protein expression and phorbol 12-myristate 13 acetate (PMA)-induced PLD activity. During neuronal differentiation, this effect showed correlation to the protein expression levels of classical protein kinase C (PKC) isozymes, PKC-alpha and -beta II, but there was no significant increase in the protein level of RhoA, another regulatory factor for PLD activation. Interestingly, PLD1 was associated with PKC-alpha or beta II, and its association gradually increased as NGF-induced neuronal differentiation progressed. PKC inhibitor, Ro-31-8220, caused a significant inhibition of neurite outgrowth and PLD activity. Furthermore, PLD1 was constitutively associated with the Shc adaptor molecule, the overexpression of which is known to induce PLD activity and to induce neurite outgrowth. Taken together, the data in this study suggests that PLD1 is closely implicated in neuronal differentiation of PC12 cells.

Phylogenetic diversity of thermophilic actinomycetes and Thermoactinomyces spp. isolated from mushroom composts in Korea based on 16S rRNA gene sequence analysis

Forty one strains isolated from 21 samples of various mushroom composts in Korea were analyzed by 16S rRNA gene sequencing to investigate the phylogenetic diversity of thermophilic actinomycetes. The 25 strains of thermophilic actinomycete isolates were related to the five genera, Pseudonocardia, Saccharomonospora, Saccharopolyspora, Streptomyces, and Thermobifida, within the order Actinomycetales, and 16 strains were classified into the genus Thermoactinomyces within the family Bacillaceae. Most of 41 isolates were encompassed by two genera, Streptomyces and Thermoactinomyces, that were isolated mainly in composts prepared from waste cotton and hay, respectively. Among them, M104 and M109 were placed in distinct taxonomic positions although these strains formed phylogenetic lineages related to the genus Streptomyces and to the family Streptosporangiaceae, respectively. Therefore, a phenetic and genetic characterization of these strains will be needed to pinpoint their taxonomic position.

Effect of somatostatin on cholecystokinin-induced amylase release in rat pancreatic acini

The effect of somatostatin on cholecystokinin-induced amylase release was investigated in isolated rat pancreatic acini. Acini were isolated by enzymatic digestion and incubated in a HEPES buffered Ringer's solution with testing reagents for 30 minutes at 37 degrees C. The activity of released amylase, cAMP, and inositol phosphate formation were measured. Intracellular calcium concentration ([Ca2+]i) was also checked. Somatostatin 14 and octreotide, a somatostatin analog, inhibited CCK-stimulated amylase release in a concentration-dependent manner. The inhibitory effect of octreotide on CCK-induced amylase release was not shown when the acini were treated with 8-Br-cAMP, irrespective of the presence of IBMX. Forskolin potentiated CCK-induced amylase release and this effect was blocked by octreotide treatment; although CCK-8 (3 x 10(-11) M) failed to stimulate cAMP formation, octreotide significantly inhibited basal cAMP formation in the acini. The increase of [Ca2+]i in response to CCK was inhibited by octreotide. However, CCK-induced inositol phosphate formation was not changed by 10(-9) M octreotide. Octreotide had no effect on CCK-stimulated tyrosine phosphorylation, and tyrosine phosphatase inhibitors (NaF and Na2WO4) did not influence the effect of octreotide on CCK-induced amylase release. From these results, we conclude that octreotide inhibits CCK-induced amylase release by inhibiting basal cAMP formation and decreasing the [Ca2+]i stimulated by CCK.

Altered expression of phospholipase D1 in spontaneously hypertensive rats

To clarify the involvement of phospholipase D (PLD) in the mechanism underlying genetically-induced hypertension, we investigated the activity and expression levels of PLD in tissues taken from spontaneously hypertensive rats (SHR), and their normotensive controls, Wistar-Kyoto rats (WKY). The ADP-ribosylation factor 3 (ARF3)-dependent PLD activity and protein levels of PLD1 from SHR increased significantly in the brain and liver, but not in the heart and kidney, compared to those of WKY. The activity and expression of PLD were the same between the homogenated whole kidneys of the two strains; however, there were topographical differences in the expression and activity of PLD between the kidneys of the two strains. The activity and expression level of PLD gradually increased from the cortex to the inner medulla of WKY. The enzyme activity, and amount of PLD in the inner stripe of the outer medulla and in the inner medulla, was significantly lower in SHR than in WKY. Taken together, these results suggest that the distinctly distributed patterns of PLD in the kidney may be associated with differential signal transduction pathways that are involved in hypertension in conjunction with an increase of PLD activity in the brain and liver.

Effects of temperature and agitation rate on the formation of conjugated linoleic acids in soybean oil during hydrogenation process

The effects of hydrogen temperature and agitation rate on the formation of total conjugated linoleic acids (CLA) and CLA isomers were studied during hydrogenation with a selective Ni catalyst. The CLA isomers were identified by using a 100-m cyano-capillary column gas chromatograph and a silver ion-impregnated HPLC. Reaction temperature and agitation rate greatly affected the quantities of total CLA and individual CLA isomers, and the time to reach the maximum quantity of CLA in the partially hydrogenated soybean oil. As the hydrogenation temperature increased, the maximum quantity of CLA in soybean oil increased, but the time to reach the maximum CLA content decreased. By increasing the hydrogenation temperature from 170 to 210 degrees C, the quantity of CLA obtained was about 2.6 times higher. As the agitation rate decreased, the CLA formation in soybean oil increased, and the time to reach the maximum CLA content also increased. The maximum CLA contents in soybean oil obtained during hydrogenation at 210 degrees C with agitation rates of 300, 500, and 700 rpm were 162.82, 108.62, and 66.15 mg total CLA/g oil, respectively. The present data showed that it is possible to produce high-CLA-content soybean oil without major modification of fatty acid composition by short-time (10 min) selective hydrogenation under high temperature and low agitation rate conditions.

Alternative embryo transfer on day 3 or day 5 for reducing the risk of multiple gestations

PURPOSE

This study was carried out to reduce the possibility of high-order multiple gestations and the failure of embryo transfer by determining their replacement date based on the number and quality of 2-day embryos.

METHODS

All zygotes were cocultured with cumulus cells in 10 microliters of YS medium containing 10% human follicular fluid (hFF) for 48 or 96 hr. In period I, all embryos were transferred on day 3 (1032 cycles). In period II, the embryos were transferred on either day 3 or day 5 by determining their replacement date based on the number and quality of 2-day embryos: there were 2701 patients in whom embryos were replaced on day 3 (in the case that the number of zygotes was less than eight and the number of good-quality embryos was less than three) and 1952 patients less than 40 years old in whom embryos were replaced on day 5 (in the case that the number of zygotes was eight or more and/or the number of good-quality embryos was three or more). On the other hand, patients who were 40 years old or more were alloted to day 3 transfer cycles, regardless of the number and quality of the 2-day embryos, due to the possibility of their not producing blastocyst-stage embryos in vitro.

RESULTS

The number of embryos transferred in period II was 2.9 +/- 0.6, while that in period I was 3.7 +/- 0.5. The multiple pregnancy rate was significantly decreased in period II (30.7%) compared to that (49.6%) in period I, while the pregnancy and implantation rates in period II (36.1 and 16.4%, respectively) were not lower than those (34.9 and 16.1%, respectively) in period I. The rate of triplet or more gestations was significantly minimized in period II (2.3%) compared to that in period I (26.5%).

CONCLUSIONS

We propose that determination of the date on which embryos should be transferred based on the number and quality of embryos on day 2 may help to maintain an acceptable pregnancy rate, while minimizing embryo transfer failure and high-order multiple gestations.

Inhibition of Kv1.3 channels by H-89 (N--[2-(p-bromocinnamylamino)ethyl]-5-isoquinolinesulfonamide) independent of protein kinase A

The effects of H-89 (N-[2-(p-bromocinnamylamino)ethyl]-5-isoquinolinesulfonamide), a potent and selective inhibitor of protein kinase A (PKA), were examined on Kv1.3 channels stably expressed in Chinese hamster ovary (CHO) cells using the patch clamp technique. In whole-cell recordings, H-89 decreased Kv1.3 currents and accelerated the decay rate of current inactivation in a concentration-dependent manner with an IC(50) value of 1.70 microM. These effects were completely reversible after washout. Intracellular infusion with PKA inhibitors, adenosine 3', 5'-cyclic phosphorothioate-Rp (Rp-cAMPS) or protein kinase A inhibitor 5-24 (PKI 5-24) had no effect on Kv1.3 currents and did not prevent the inhibitory action of H-89 on the current. H-89 applied to the cytoplasmic surface also inhibited Kv1.3 currents in excised inside-out patches. These findings suggest that H-89 inhibits Kv1.3 currents independently of PKA.

A comparison of bowel care patterns in patients with spinal cord injury: upper motor neuron bowel vs lower motor neuron bowel

STUDY DESIGN

A face-to-face interview survey.

OBJECTIVE

To compare bowel care patterns in spinal cord injury (SCI) patients based on type of neurogenic bowel.

SETTING

Department of Physical Medicine and Rehabilitation of a tertiary university hospital in Suwon, Korea.

METHODS

Among chronic SCI patients, 22 patients with upper motor neuron bowel (UMNB) and 20 patients with lower motor neuron bowel (LMNB) participated in an interview survey for the evaluation of bowel care patterns.

RESULTS

The patients with LMNB demonstrated increased frequency of defecation, increased frequency of fecal incontinence, increased use of oral medications for bowel care, increased required time for defecation and more diet modification than those with UMNB (P < 0.05). However, there was no significant difference in the subjective difficulty of bowel care. Among several available bowel care methods, suppositories were used most frequently by the UMNB group, whereas the Valsalva maneuver was the most frequently used method by the LMNB group.

CONCLUSIONS

Patients with LMNB tend to suffer more difficulties in management of their neurogenic bowel than those with UMNB. Therefore, more intensive and aggressive bowel care programs should be provided for SCI patients with LMNB.

The involvement of phospholipase A(2) in ethanol-induced gastric muscle contraction

To understand the underlying mechanism of ethanol in tonic contraction, the effect of ethanol on phospholipase A(2) and phospholipase C activities and the effects of phospholipase inhibitors on ethanol-induced contraction of cat gastric smooth muscle were tested. Circular muscle strips (2.0 x 0.2 cm) obtained from the fundus of cat stomach were used to measure isometric contraction. Ethanol elicited tonic contraction and activated phospholipase A(2) activity in a dose-dependent manner. Phospholipase A(2) inhibitors, manoalide (0.1--10 microM) and oleyloxyethyl phosphorylcholine (1--10 microM), significantly inhibited ethanol-induced contraction. Furthermore, 342 mM ethanol-induced contraction was significantly inhibited by cyclooxygenase inhibitors, ibuprofen (10--100 microM) and indomethacin (10--100 microM), but not by lipoxygenase inhibitors. On the other hand, phospholipase C inhibitors had no effect on ethanol-induced contraction, indicating that phospholipase C is not involved in ethanol-induced contraction. It is suggested from the above results that ethanol-induced contraction in cat gastric smooth muscle is, in part, mediated by phospholipase A(2) and cyclooxygenase pathways.

High production of D-tagatose, a potential sugar substitute, using immobilized L-arabinose isomerase

An L-arabinose isomerase of Escherichia coli was immobilized using covalent binding to agarose to produce D-tagatose, a bulking sweetener that can be economically used as a sugar substitute. The immobilized L-arabinose isomerase stably produced an average of 7.5 g-tagatose/L.day for 7 days with a productivity exceeding that of the free enzyme (0.47 vs 0.30 mg/U.day). Using a scaled-up immobilized enzyme system, 99.9 g-tagatose/L was produced from galactose with 20% equilibrium in 48 h. The process was repeated two more times with production of 104.1 and 103.5 g-tagatose/L. D-Tagatose production using an immobilized L-arabinose isomerase has a high potential for commercial application.