Mechanism of fluoxetine block of cloned voltage-activated potassium channel Kv1.3

The effects of fluoxetine (Prozac), a widely used antidepressant drug, on Kv1.3 stably expressed in Chinese hamster ovary cells were examined using the whole-cell and excised inside-out configurations of the patch-clamp technique. In whole-cell recordings, fluoxetine accelerated the decay rate of inactivation of Kv1.3 and thus decreased the current amplitude at the end of the pulse in a concentration-dependent manner with an IC(50) value of 5.9 microM. The inhibition displayed a weak voltage dependence, increasing at more positive potentials. Neither the activation nor the steady-state inactivation curve was affected by fluoxetine. In addition, fluoxetine reduced the tail current amplitude and slowed the deactivation of the tail current, resulting in a crossover phenomenon. When applied to the internal side of the membrane in inside-out recordings, the inhibition by fluoxetine was much faster and more potent with an IC(50) value of 1.7 microM compared with whole-cell recordings. Norfluoxetine, the major metabolite of fluoxetine, also inhibited Kv1.3 in a concentration-dependent manner (IC(50) = 1.4 microM) in whole-cell recordings. To check whether the fluoxetine-induced inhibition demonstrated in cloned Kv1.3 could also be observed in native T lymphocytes, the effects of fluoxetine were investigated on human T lymphocytes. Fluoxetine also inhibited outward K(+) current in human T lymphocytes. Our results indicate that fluoxetine produced a concentration- and voltage-dependent inhibition of Kv1.3 that can be interpreted as an open channel block and that a binding site for fluoxetine is more accessible from the intracellular side.

Influence of 5,10-methylenetetrahydrofolate reductase gene polymorphism on plasma homocysteine concentration in patients with end-stage renal disease

The purpose of this study is to observe the influence of the methylenetetrahydrofolate reductase (MTHFR) gene (677C-->T substitution) on plasma homocysteine levels in end-stage renal disease (ESRD) patients who received a relatively large amount of folate (2 mg/d) and are undergoing hemodialysis. A cross-sectional study of plasma homocysteine, vitamin B(12), and folate was performed in patients with ESRD. The study population for the MTHFR gene study included 312 healthy subjects and 106 patients with ESRD undergoing hemodialysis. The C677T transition in the MTHFR gene was detected by HinF 1 restriction enzyme analysis and subsequent electrophoresis in a 3% agarose gel. The genotype of the MTHFR gene in 106 patients with ESRD was homozygous C677T mutation (VV) in 17 patients (16.1%) and heterozygous (AV) in 63 patients (58.4%); 26 patients (24.5%) did not carry this mutation (AA). The mean levels of homocysteine, vitamin B(12), and folate in the patients with ESRD were 23.3 +/- 14.0 mmol/L, 620.2 +/- 98.5 pmol/L, and 138.6 +/- 55.6 nmol/L, respectively. There was no significant difference in homocysteine levels among the three genotypes: 28.2 +/- 19.4 mmol/L for VV, 22.7 +/- 14.9 mmol/L for AV, and 23.4 +/- 11.1 mmol/L for AA genotype (P > 0.05). There was no difference in genotype distribution between the patient groups of less than 25th and greater than 75th percentiles, classified according to plasma homocysteine levels (P = 0.47). In conclusion, with high-dose folate supplementation, the hyperhomocysteinemia in patients with ESRD does not seem to be caused by the 677C-->T mutation in the MTHFR gene.

Identification of acylated glycoglycerolipids from a cyanobacterium, Synechocystis sp., by tandem mass spectrometry

Acylated glycoglycerolipids were identified in the total lipid extract from cyanobacterium Synechocystis sp. PCC 6803. These compounds have a palmitoyl group esterified to the hydroxyl group at the C-6 position of the terminal glycosyl moiety of digalactosyl monoacylglycerol and digalactosyl diacylglycerol. Their structural elucidation was accomplished by tandem mass spectrometry coupled with fast atom bombardment ionization. Acylated digalactosyl monoacylglycerol has a structure of 1-hydroxy-2-palmitoyl-3-O-[(6-O-palmitoyl)-alpha-D-galactopyranosyl -(1-->6)-beta-D-galactopyranosyl]-sn-glycerol. This compound has not been reported previously.

Imported tertian malaria resistant to primaquine

In Plasmodium vivax and Plasmodium ovale malaria, some of the liver stage parasites remain dormant. The activation of these dormant forms (called hypnozoite) can give rise to relapse weeks, months or years after the initial infection. To prevent relapses, a course of primaquine may be given as terminal prophylaxis to patients. Different strains of Plasmodium vivax vary in their sensitivity to primaquine and, recently, cases of relapse of Plasmodium vivax after this standard primaquine therapy were reported from various countries. We reported a case of primaquine resistant malaria which initially was thought to be relapsed caused by loss of terminal prophylaxis.

Photomovement of the gliding cyanobacterium Synechocystis sp. PCC 6803

Using a computerized videomicroscope motion analysis system, we investigated the photomovements of two Synechocystis sp. (PCC 6803 and ATCC 27184). Synechocystis sp. PCC 6803 displays a relatively slow gliding motion. The phototactic and photokinetic speeds of this cyanobacterium in liquid media were 5 microns/min and 15.8 microns/min, respectively, at 3 mumol/m2/s of stimulant white light. Synechocystis sp. PCC 6803 senses light direction rather than intensity for phototaxis. Synechocystis sp. ATCC 27184 showed a weak photokinesis but no phototaxis. Analysis of Synechocystis sp. ATCC 27184 suggests that the loss of phototaxis results from spontaneous mutation during several years of subculture. When directional irradiation was applied, the cell population of Synechocystis sp. PCC 6803 began to deviate from random movement and reached maximum orientation at 5 min after the onset of stimulant white light. Synechocystis sp. PCC 6803 showed high sensitivity to the stimulant white light of fluence rates as low as 0.002 mumol/m2/s. Neither 1,3-dichlorophenyldimethyl urea nor cyanide affected phototactic orientation, whereas cyanide inhibited gliding speed. This result suggests that the phototaxis of Synechocystis sp. PCC 6803 is independent of photosynthetic phosphorylation and that its gliding movement is primarily powered by oxidative phosphorylation. In the visible wavelength region, 560 nm, 660 nm and even 760 nm caused positive phototaxis. However, 360 nm light induced strikingly negative phototaxis. Therefore, at least two independent photoreceptors may exist to control phototaxis. The photoreceptor for positive phototaxis appears likely to be a phytochrome-like tetrapyrrole rather than chlorophyll a.

Inhibitory effect of luteolin 4'-O-glucoside from Kummerowia striata and other flavonoids on interleukin-5 bioactivity

Interleukin (IL)-5 is a chemotactic factor of eosinophils, and promotes the growth and survival of eosinophils, which plays an important role in the eosinophilia-associated allergic inflammation. In this study, luteolin 4'-O-glucopyranoside was identified as the IL-5 inhibitor from Kummerowia striata Thunb. (Leguminosae) by activity-guided fractionation followed by structural analysis compared with reported spectral data. The flavone compound exhibited dose-dependent inhibitory effect on IL-5 bioactivity with 95% inhibition at 30 microM, 79% at 15 microM, 60% at 7.5 microM, 54% at 3.8 microM and 29% at 1.9 microM, where 50% of inhibition (IC50) value was shown at the concentration of 3.7 microM. Furthermore, the inhibitory effect on IL-5 bioactivity by other flavonoid compounds available was estimated. In view of the IC50 values, the inhibitory potency on IL-5 bioactivity was in order of luteolin 4'-O-glucopyranoside > cosmosiin (14.2 microM) approximately equal to apigenin (16.4 microM) approximately equal to luteolin (18.7 microM) > quercimeritrin (27.3 microM) approximately equal to kaempferol (30.0 microM).

In vivo experiment leading to clinical application of an electrohydraulic ventricular assist device with magnetic coupling

We developed an electrohydraulic ventricular assist device with magnetic coupling. The integrated system consists of a blood pump, a water conduit for pressure transmission, a bellows type pumping sac, an actuator for transforming the circular motion of a motor to the linear motion of a pusher plate attached to the pumping sac with magnetic coupling, and a controller. The purpose of the coupling was to prevent excessive sucking against the atrial wall. Number 21 Medtronic Hall (Irvine, CA) mechanical valves were used in the inflow and outflow ports of the blood pump. Maximum dynamic stroke volume was 48 ml, and against a mean afterload of 100 mm Hg, maximum pump output was 7 L/min. Chronic in vivo experiments were performed in three sheep, and during these evaluations the system showed no noticeable problems related to mechanical or electronic devices. When left atrial pressure decreased below 0 mm Hg, the magnetic coupling system decoupled the pumping sac and pusher plate with satisfactory reliability. The device was clinically applied in a postoperative patient with chronic dilating cardiomyopathy, and no significant device related problems ensued. These results prove that the electrohydraulic ventricular assist system with magnetic coupling is a suitable ventricular assist device.

Staurosporine directly blocks Kv1.3 channels expressed in Chinese hamster ovary cells

The effects of staurosporine (ST), a widely used protein kinase C (PKC) inhibitor, were examined on Kv1.3 channels stably expressed in Chinese hamster ovary (CHO) cells using the whole-cell and excised inside-out configurations of the patch clamp technique. In whole-cell recordings, ST, at external concentrations from 300 nM to 10 microM, accelerated the rate of inactivation of Kv1.3 currents and thereby reduced the current at the end of the depolarizing pulse in a concentration-dependent manner with an IC50 of 1.2 microM. The actions of ST were unaffected by pretreatment with another selective PKC inhibitor, chelerythrine, or by including the PKC pseudosubstrate peptide inhibitor, PKC 19-36, in the intracellular solution. Rp-cAMPS, a specific protein kinase A inhibitor, included in intracellular solution did not affect the effects of ST. Furthermore, the same effects of ST on Kv1.3 were also observed in excised inside-out patches when applied to the internal face of the membrane. These effects were completely reversible upon washing. Current-voltage relations for Kv1.3 currents at the end of voltage steps indicated that ST reduced Kv1.3 currents over a wide voltage range. The blockade exhibited a shallow voltage dependence between -10 mV and +40 mV, increasing at more positive potentials. ST had no effect on the voltage dependence of steady-state inactivation. It reduced the tail current amplitude and slowed the deactivation time course, resulting in a crossover phenomenon. These results suggest that the action of ST on Kv1.3 is independent of PKC and PKA inhibition. ST blocks the open state of Kv1.3 channels to produce an apparent acceleration of the inactivation rate.

Reactive oxygen species-induced apoptosis and necrosis in bovine corneal endothelial cells

PURPOSE

The loss of corneal endothelial cells associated with aging and possibly other causes has been speculated to be related to exposure to reactive oxygen species (ROS). The current study was conducted to investigate, by use of photosensitizers, the underlying mechanisms involved in the death of bovine corneal endothelial cells (BCENs) caused by ROS.

METHODS

BCEN cells in primary culture were treated with a photosensitizer (riboflavin or rose bengal) with light exposure. The patterns of cell damage and death were assessed using an acridine orange-ethidium bromide differential staining method, TdT-mediated dUTP nick-end labeling (TUNEL) assay, and transmission electron microscopy. The cytotoxicity was assayed by mitochondrial function using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) testing. Antioxidants, including catalase, L-histidine, salicylic acid, and superoxide dismutase, were used to determine the types of ROS involved. Activation of nuclear factor (NF)-kappaB was examined by fluorescent immunocytochemistry with anti-p65 antibody.

RESULTS

Light-irradiated riboflavin or rose bengal resulted in a significant decrease in viability of BCEN cells. Chromosomal condensation and fragmentation were observed in apoptotic cells, and membrane lysis and damage of cell ultrastructures were observed in necrotic cells. Riboflavin induced apoptosis at 30 minutes and thereafter and induced necrosis after 2 hours. Rose bengal was shown to cause similar effects within half the time required for the effects of riboflavin. Catalase and salicylic acid were found to provide protection for BCENs from cytotoxic effects of riboflavin, and L-histidine was found to protect BCENs from cytotoxicity induced by rose bengal. Kinetic studies using immunocytochemistry showed that NF-kappaB was translocated into the nucleus within 15 minutes and 30 minutes after treatment with rose bengal and riboflavin, respectively.

CONCLUSIONS

The cytotoxic effects of photo-irradiated riboflavin and rose bengal are shown to be mediated by two distinct but parallel pathways, one leading to apoptosis and the other to necrosis. Possible involvement of NF-kappaB in cell death is suggested. These findings provide potential leads for future investigation into the molecular mechanisms of loss of corneal endothelial cells related to aging, oxidative stress, and possibly other similar causes.

Antioxidant flavonoids and chlorogenic acid from the leaves of Eriobotrya japonica

The antioxidant activity of Eriobotrya japonica was determined by measuring the radical scavenging effect on DPPH (1,1-diphenyl-2-picrylhydrazyl) radical and lipid peroxidation produced when mouse liver homogenate was exposed to the air at 37 degrees C, using 2-thiobarbituric acid (TBA). The methanol extract and its fractions of Eriobotrya japonica leaves showed strong antioxidant activity. The antioxidant activity of EtOAc and n-BuOH soluble fractions were stronger than the others, and were further purified by repeated silica gel, MCl gel CHP-20P, and Sephadex LH-20 column chromatography. Antioxidant chlorogenic acid, quercetin-3-sambubioside from n-BuOH fraction, and methyl chlorogenate, kaempferol- and quercetin-3-rhamnosides, together with the inactive ursolic acid and 2 alpha-hydroxyursolic acid from EtOAc fraction were isolated. Antioxidant flavonoids and chlorogenic acid also showed prominent inhibitory activity against free radical generation in dichlorofluorescein (DCF) method.

Improved cycle sequencing of GC-rich DNA template

Even when DNA sequencing of purified DNA template failed under the optimal condition, it can be generally contributed to high GC content. GC-rich region of template causes a secondary structure to produce shorter readable sequence. To solve this problem, the sequencing reaction was modified by using dimethyl sulfoxide (DMSO). It was found that 5% (v/v) of DMSO in the reaction mixture recovers sequencing signal intensity with reduced frequency of ambiguous bases. When DMSO was added to sequencing reaction of DNA template with normal GC content, it did not show any adverse effect. Sequencing accuracy and unambiguous base frequency were significantly improved at concentration of 2% to 5% (v/v) DMSO in GC-rich DNA template. DMSO has been empirically introduced to enhance the efficiency of PCR in GC-rich templates. However, the underlying mechanism of improved cycle sequencing by DMSO is unknown. Thus, cycle sequencing reaction was remodified with other additives such as N-methyl imidazole, N-methyl2-pyrrolidone, N-methyl-2-pyridone and glycerol, possessing the similar chemical properties as DMSO. Most of methyl nitrogen ring-containing chemicals did not improve sequencing accuracy, whereas only glycerol mimicked the positive effect of DMSO by the same extent. In the present study, we suggest that the treatment of DMSO improve cycle sequencing by the alteration of structural conformation of GC-rich DNA template.

Necrosis and apoptosis after retinal ischemia: involvement of NMDA-mediated excitotoxicity and p53

PURPOSE

Accumulated evidence has shown that apoptosis and necrosis contribute to neuronal death after ischemia. The present study was performed to study the temporal and spatial patterns of neuronal necrosis and apoptosis after ischemia in retina and to outline mechanisms underlying necrosis and apoptosis.

METHODS

Retinal ischemia was induced by increasing intraocular pressure to a range of 160 mm Hg to 180 mm Hg for 90 minutes in adult rats. The patterns of neuronal cell death were determined using light and electron microscopy and were visualized by TdT-dUTP nick-end labeling (TUNEL). The mRNA expression profile of p53 was examined using reverse transcription-polymerase chain reaction (RT-PCR) and in situ hybridization histochemistry. Immunohistochemistry was performed using anti-p53, anti-microtubule associated protein-2, and anti-glial fibrillary acidic protein antibodies.

RESULTS

Within 4 hours after ischemia, neurons in the inner nuclear cell layer (INL) and ganglion cell layer (GCL) underwent marked necrosis, made apparent by swelling of the cell body and mitochondria, early fenestration of the plasma membrane, and irregularly scattered condensation of nuclear chromatin. After 3 days, the INL and GCL neurons showed further degeneration through apoptosis marked by cell body shrinkage, aggregation, and condensation of nuclear chromatin. Apoptotic neurons were also observed sparsely in the outer nuclear cell layer. Intravitreal injections of MK-801 prevented early neuronal degeneration after ischemia. Of note, mRNA and protein levels of p53, the tumor suppressor gene known to induce apoptosis, were increased in the retinal areas undergoing apoptosis 1 to 3 days after ischemic injury.

CONCLUSIONS

Ischemia produces the N-methyl-D-aspartate-mediated necrosis and slowly evolving apoptosis of neurons in the retina. The latter may depend on the expression of the p53 proapoptosis gene.

Structural identification of glycerolipid molecular species isolated from cyanobacterium Synechocystis sp. PCC 6803 using fast atom bombardment tandem mass spectrometry

Our previous works have demonstrated that fast atom bombardment tandem mass spectrometry can be a valuable tool in determining the complete structure of glycoglycerolipids and glycerophospholipids. Collision-induced dissociation of sodium-adducted molecular ions ([M + Na]+ or [M - H + 2Na]+) generates diverse product ions informative on the double-bond position in fatty acyl groups as well as the polar head group and fatty acid composition. Here we report that this direct and rapid method can be applied to the structural determination of individual molecular species of each glycerolipid class purified from the total lipid extract of cyanobacterium Synechocystis sp. PCC 6803. Especially, based on the preference for the loss of the fatty acyl group positioned at the sn-2, it was proved that all of the molecular species of diacylglycerolipids contained a palmitoyl group exclusively at the sn-2 position. Additionally, lysoglycerolipids, monoacyl forms of four major membrane diacylglycerolipids, were first isolated together from a fresh extract. Using fast atom bombardment mass spectrometry and tandem mass spectrometry, it was found that each lysoglycerolipid had a molecular species with only palmitic acid as a fatty acyl group. Thus, these compounds could be synthesized by specific enzyme-catalyzed hydrolysis of the sn-1 fatty acyl group of the corresponding diacylglycerolipids.

Inhibition by fluoxetine of voltage-activated ion channels in rat PC12 cells

The effects of fluoxetine (Prozac) on voltage-activated K+, Ca2+ and Na+ channels were examined using the whole-cell configuration of the patch clamp technique in rat pheochromocytoma (PC12) cells. When applied to the external bath solution, fluoxetine (1, 10, 100 microM) decreased the peak amplitude of K+ currents. The K+ current inhibition by fluoxetine (10 microM) was voltage-independent and the fraction of current inhibition was 39.7-51.3% at all voltages tested (0 to +50 mV). Neither the activation and inactivation curves nor the reversal potential for K+ currents was significantly changed by fluoxetine. The inhibition by fluoxetine of K+ currents was use- and concentration-dependent with an IC50 of 16.0 microM. The inhibition was partially reversible upon washout of fluoxetine. The action of fluoxetine was independent of the protein kinases, because the protein kinase C or A inhibitors (H-7, staurosporine, Rp-cAMPS) did not prevent the inhibition by fluoxetine. Intracellular infusion with GDPbetaS or pretreatment with pertussis toxin did not block the inhibitory effects of fluoxetine. The inhibitory action of fluoxetine was not specific to K+ currents because it also inhibited both Ca2+ (IC50 = 13.4 microM) and Na+ (IC50 = 25.6 microM) currents in a concentration-dependent manner. Our data indicate that when applied to the external side of cells, fluoxetine inhibited voltage-activated K+, Ca2+ and Na+ currents in PC12 cells and its action on K+ currents does not appear to be mediated through protein kinases or G proteins.

Poly(ethylene glycol)-block-poly(L-lysine) dendrimer: novel linear polymer/dendrimer block copolymer forming a spherical water-soluble polyionic complex with DNA

Methoxypoly(ethylene glycol)-block-poly(L-lysine) dendrimer was designed to form a water-soluble complex with plasmid DNA. The copolymer was synthesized by the liquid-phase peptide synthesis method. It was characterized by 1H NMR and matrix-assisted laser desorption ionization-time-of-flight (MALDI-TOF) mass spectrum. Agarose gel electrophoresis and DNase I protection assay proved that this linear polymer/dendrimer block copolymer assembled spontaneously with plasmid DNA, forming a water-soluble complex which increased the stability of the complexed DNA. Atomic force microscopy of the complex was evaluated at various charge ratios showing that the copolymer/DNA complex was like a globular shape.

Circadian changes in pharmacokinetics of cyclosporin in healthy volunteers

Circadian changes in the pharmacokinetics of cyclosporin were evaluated after oral administration of the drug, 300 mg, at 09:00 and 20:00 to twelve healthy male subjects. At 09:00, the blood concentrations of cyclosporin were higher, the area under the blood concentration-time curve from time 0 to time infinity was significantly greater (9.70 versus 8.42 microg x hr/ml), and the renal clearance was significantly slower (1.14 versus 1.48 ml/min) than those at 22:00. The terminal half-life, peak concentration, and time to reach peak concentration were not significantly different between two groups.

In vitro angiogenic activity of Aloe vera gel on calf pulmonary artery endothelial (CPAE) cells

Angiogenic activity of Aloe vera gel was investigated by in vitro assay. We obtained the most active fraction from dichloromethane extract of Aloe vera gel by partitioning between hexane and 90% aqueous methanol. The most active fraction (F3) increased the proliferation of calf pulmonary artery endothelial (CPAE) cells. In addition, F3 fraction induced CPAE cells to invade type 1 collagen gel and form capillary-like tube through in vitro angiogenesis assay, and increased the invasion of CPAE cells into matrigel through in vitro invasion assay. Furthermore, the effect on the mRNA expression of proteolytic enzymes which are key participants in the regulation of extracellular matrix degradation was investigated by northern blot analysis. F3 fraction enhanced mRNA expression of urokinase-type plasminogen activator (u-PA), matrix metalloproteinase-2 (MMP-2), and membrane-type MMP (MT-MMP) in CPAE cells whereas the expression of plasminogen activator inhibitor-1 (PAI-1) mRNA was not changed.

Prevalence and disease experience rates in Korean physicians

This study aimed to find out the morbid status of Korean physicians living in Korea, as one part of a feasibility study on the Korean physician cohort. It was performed by mail survey using a self-administered questionnaire from Jan. 1, 1995 through Dec. 31, 1995. Study subjects were 21,552 including 17,877 (81.1%) males and 3,384 (15.5%) females. Person based prevalence rate of disease was 17.7% (18.3% for males and 13.8% for females) with the rate increasing with age. The disease group showing the highest prevalence rate was circulatory diseases (5.16%) for males, and respiratory disease (3.13%) for females. The individual disease showing the highest prevalence rates was hypertension (3.77%) for males and allergic rhinitis (2.25%) for females. The person based disease experience rate was 36.2% (36.9% for males, 32.7% for females) with the rate increasing with age. The disease group showing the highest disease experience rate was digestive disease for both sexes (10.05% for males, 7.42% for females). Individual disease showing the highest disease experience rate was hypertension (5.00%) for males and allergic rhinitis (4.08%) for females. There were different ranks of both prevalence and disease experience rate depending on age in both sexes.

NF-kappa B activation following optic nerve transection

In order to elucidate in vivo neuronal cell death in the retina, and involvement of NF-kappa B in this process, we studied the degeneration of retinal ganglion cells (RGCs) and the activation of NF-kappa B after transection of the optic nerve of adult rat at 5 mm from the eyeball. The morphology of dying ganglion cells in the retinal ganglion cell layer was observed by light and electron microscopy, the activation of NF-kappa B was investigated immunohistochemically. Seven and 14 days post-axotomy, dying cells contained pyknotic nuclei. The death of retinal ganglion cells involved apoptosis, activation of NF-kappa B (p50 and p65) was prominent in a time dependent manner. We observed axotomy-induced NF-kappa B activation, which may mediate apoptosis of retinal ganglion cells.

Expression of hMSH2 and hMLH1 in colorectal carcinomas with microsatellite instability

Microsatellite instability (MIN) due to defective mismatch repair (MMR) genes has been reported in a subset of sporadic colorectal carcinomas and in the majority of tumors from patients with hereditary nonpolyposis colorectal cancer (HNPCC) syndrome. Among the known MMR genes, hMSH2 and hMLH1 genes are known to be predominantly altered in HNPCC patients and MIN-positive tumors. In this study, we examined MIN and the protein expression pattern of the hMSH2 and hMLH1 by Western blot and immunohistochemistry from 32 sporadic colorectal carcinomas. MIN was observed in 6 (18%) colorectal carcinomas. Of the 6 MIN-positive tumors, one case showed no expression of either protein, 3 cases showed an absence of hMSH2 protein expression, one case showed an absence of hMLH1 protein expression and one case showed no altered expression of either protein by immunohistochemistry. The decreased expression of the hMSH2 protein in a tumor compared to the normal mucosa was also observed in 5 of the 6 MIN-positive cases by Western blot analysis. All of the MIN-negative tumors showed expression of both proteins by immunohistochemistry. Thus most of the MIN-positive tumors appear to be directly related to the altered expression of these two genes and can be diagnosed by the examination of protein expression.

In vitro activation of pro-phenol-oxidase by two kinds of pro-phenol-oxidase-activating factors isolated from hemolymph of coleopteran, Holotrichia diomphalia larvae

Previously, we purified and characterized a pro-phenol-oxidase (pro-PO) of 79 kDa from coleopteran insect, Holotrichia diomphalia larvae [Kwon et al. (1997) Mol. Cells 7, 90-97]. Here, we describe the identification of two pro-PO-activating factors (PPAF), named PPAF-I and PPAF-II, directly involved in the activation of the isolated pro-PO. When pro-PO was incubated with either PPAF-I or PPAF-II, no phenol oxidase activity was observed. However, incubation of pro-PO with both PPAF-I and PPAF-II specifically exhibited phenol oxidase activity. The purified PPAF-I with a molecular mass of 33 kDa on SDS/PAGE had characteristics of a serine protease. It exhibited amidase activity against fluorogenic peptide substrates, tert-butoxycarbonyl-phenylalanyl-seryl-arginyl-4-methylcoumaryl-7-amide being the best among the substrates examined. The activity was completely inhibited by 0.02 mM p-nitrophenyl-p'-guanidinobenzoate HCl and diisopropylflurophosphate. The NH2-terminal sequence of PPAF-I had significant sequence similarity to those of serine proteases. On the other hand, the purified PPAF-II had a molecular mass of 40 kDa on SDS/PAGE and 400 kDa determined by gel filtration, indicating an oligomeric protein. The NH2-terminal sequence of PPAF-II showed no similarity to known proteins. PPAF-II exhibited no amidase activity against the fluorogenic substrates. Reconstitution experiments and immunoblotting analysis using affinity-purified antibody against pro-PO demonstrated that PPAF-I first cleaves the intact pro-PO to an intermediate of 76 kDa with no phenol oxidase activity, and then, PPAF-I converts the intermediate to the active phenol oxidase of 60 kDa in the presence of PPAF-II. These results indicate that the activation of pro-PO system in hemolymph of H. diomphalia larvae is accomplished by at least two activating factors, a serine protease and a protein cofactor.

Structure-related inhibition of human hepatic caffeine N3-demethylation by naturally occurring flavonoids

The effects of flavonoids on caffeine N3-demethylation, a marker activity of CYP1A2, in human liver microsomes were investigated to elucidate the inhibition mechanism and the structure-activity relationship. Caffeine N3-demethylase activity was inhibited by the presence of various flavonoids, whose structures seem to be closely related to the degree of inhibition. Among twenty-one compounds tested, the most active was chrysin with an IC50 value of 0.2 microM. Others had IC50 values ranging from 1 to more than 500 microM. Kinetic analysis revealed that the mechanism of inhibition varied among the flavonoids. The inhibitory effect was postulated to be governed by factors such as the number of hydroxyl groups and glycosylation of these free hydroxyl groups. An increase in the number of free hydroxyl groups reduced the inhibitory effect on P450 activity. Analysis of the quantitative structure-activity relationship (QSAR) showed that the volume to surface area ratio was the most effective factor on the inhibition of caffeine N3-demethylation, and the electron densities on the C3 and C4' atoms exercised significant influence on the inhibitory effect. The calculated inhibitory effect of flavonoids on CYP1A2 activity was highly correlated with the antimutagenicity of flavonoids in 2-amino-3,4-dimethylimidazo[4,5-flquinoline (MelQ)-induced umu response.

Renal transport systems for organic anions and cations in cadmium-exposed rats

To evaluate the effect of cadmium intoxication on renal transport systems for organic anions and cations, transport of p-aminohippurate (PAH) and tetraethylammonium (TEA) were studied in renal cortical plasma membrane vesicles isolated from cadmium-intoxicated rats. Cadmium intoxication was induced by daily injections of CdCl2 (2 mg Cd/kg.day sc) for 2-3 weeks. Renal plasma membrane vesicles were prepared by Percoll gradient centrifugation and magnesium precipitation method. Vesicular uptake of substrate was determined by rapid filtration technique using Millipore filter. The cadmium treatment resulted in a marked attenuation of Na(+)-dependent, alpha-ketoglutarate (alpha KG)-driven PAH uptake in the basolateral membrane vesicle (BLMV), and this was due to a reduction in Vmax and not K(m). The Na(+)-alpha KG symport activity of the BLMV was not affected by 2-week cadmium treatment, but it was significantly inhibited by 3-week cadmium treatment. On the other hand, the alpha KG-PAH antiport activity of the BLMV appeared to be markedly suppressed in 2-week as well as 3-week cadmium-treated animals. The cadmium treatment inhibited the proton gradient-dependent TEA transport in the brush-border membrane vesicle (BBMV), and this was associated with a reduction in Vmax with no change in K(m). These results indicate that cadmium exposures may impair the capacities for organic anion transport in the proximal tubular basolateral membrane and organic cation transport in the luminal membrane. The cadmium effect on organic anion transport is attributed mainly to an inhibition of dicarboxylate-organic anion antiport system.

Organization and transcriptional characterization of the cat1 gene cluster in Acinetobacter lwoffi K24

Previously, we have reported that two clustered cat genes from Acenitobacter lwoffi K24 had different arrangements, catB1C1A1 and catB2A2C2 (Kim, S.I., S.-H. Leem, J.-S. Choi, Y.H. Chung, S. Kim, Y.-M. Park, Y.K. Park, Y.N. Lee, and K.-S. Ha. 1997, J. Bacteriol. 179, 5226-5231). By further analysis of the organization of the cat1 gene cluster, we obtained a complete sequence of the catB1 gene, which encoded 40.8-kDa polypeptide containing 379 amino acids, and found a open reading frame (ORF) coding a putative regulatory protein in upstream region of catB1 on plasmid pCD1-1. This ORF encoded 34.2-kDa polypeptide containing 379 amino acids and had more than 40% identity with catR, LysR family regulatory protein of Pseudomonas putida. RT-PCR, Northern blot analysis and primer extension assay for transcriptional analysis of the cat1 gene cluster revealed that the catB1C1 genes were cotranscribed and the catA1 gene was independently transcribed.

Two hevein homologs isolated from the seed of Pharbitis nil L. exhibit potent antifungal activity

Two antifungal peptides (Pn-AMP1 and Pn-AMP2) have been purified to homogeneity from seeds of Pharbitis nil. The amino acid sequences of Pn-AMP1 (41 amino acid0 residues) and Pn-AMP2 (40 amino acid residues) were identical except that Pn-AMP1 has an additional serine residue at the carboxyl-terminus. The molecular masses of Pn-AMP1 and Pn-AMP2 were confirmed as 4299.7 and 4213.2 Da, respectively. Both the Pn-AMPs were highly basic (pI 12.02) and had characteristics of cysteine/glycine rich chitin-binding domain. Pn-AMPs exhibited potent antifungal activity against both chitin-containing and non-chitin-containing fungi in the cell wall. Concentrations required for 50% inhibition of fungal growth were ranged from 3 to 26 micrograms/ml for Pn-AMP1 and from 0.6 to 75 micrograms/ml for Pn-AMP2. The Pn-AMPs penetrated very rapidly into fungal hyphae and localized at septum and hyphal tips of fungi, which caused burst of hyphal tips. Burst of hyphae resulted in disruption of the fungal membrane and leakage of the cytoplasmic materials. To our knowledge, Pn-AMPs are the first hevein-like proteins that show similar fungicidal effects as thionins do.

Basal cell adenocarcinoma of the salivary gland--a case report

Basal cell adenocarcinoma of the salivary gland is a very rare disease entity as the malignant counterpart of basal cell adenoma. On the basis of morphologic pattern, basal cell adenoma can be divided into four subtypes; trabecular, solid, tubular, and dermal analogue (membranous). We report a case of basal cell adenocarcinoma in the left parotid gland of a 33-year-old woman. Light microscopically, the tumor cells were composed of relatively uniform, monotonous basaloid cells. The tumor cell nests commonly had peripheral palisadings. The main growth pattern of the tumor cells was tubulotrabecular. However, other portions were similar to dermal analogue monomorphic adenoma and showed cribriform patterns reminiscent of adenoid cystic carcinoma. The tumor had frequent perineural invasions and an infiltrative margin. On immunohistochemistry, only scattered numbers of tumor cells showed irregular positive reaction for S-100 protein, suggesting a few myoepithelial cell components of the tumor compared with most tumor cells derived from epithelial cells.

A triterpenoid saponin from Patrinia scabiosaefolia

A new triterpenoid saponin, patrinia saponin H3 (3), was isolated from the aerial parts of Patrinia scabiosaefolia Fisch. and determined to be 3-O-beta-D-glucopyranosyl(1-->3)-alpha-L-rhamnopyranosyl (1-->2)-alpha-L-arabinopyranosyl hederagenin 28-O-alpha-L-rhamnopyranosyl (1-->4)-beta-D-glucopyranosyl(1-->6)-beta-D-glucopyranosyl ester on the basis of NMR and FAB MS experiments and acid hydrolysis.

Cloning and characterization of two catA genes in Acinetobacter lwoffii K24

Two novel type I catechol 1,2-dioxygenases inducible on aniline media were isolated from Acinetobacter lwoffii K24. Although the two purified enzymes, CD I1 and CD I2, had similar intradiol cleavage activities, they showed different substrate specificities for catechol analogs, physicochemical properties, and amino acid sequences. Two catA genes, catA1 and catA2, encoding by CD I1 and CD I2, respectively, were isolated from the A. lwoffii K24 genomic library by using colony hybridization and PCR. Two DNA fragments containing the catA1 and catA2 genes were located on separate regions of the chromosome. They contained open reading frames encoding 33.4- and 30.4-kDa proteins. The amino acid sequences of the two proteins matched well with previously determined sequences. Interestingly, further analysis of the two DNA fragments revealed the locations of the catB and catC genes as well. Moreover, the DNA fragment containing catA1 had a cluster of genes in the order catB1-catC1-catA1 while the catB2-catA2-catC2 arrangement was found in the catA2 DNA fragment. These results may provide an explanation of the different substrate specificities and physicochemical properties of CD I1 and CD I2.

A randomized trial comparing cisplatin plus 5-fluorouracil with or without levamisole in operable gastric cancer

OBJECTIVES

To determine the effectiveness and toxicity when levamisole was added to the adjuvant combination chemotherapy in patients with operable gastric cancer.

METHODS

After en bloc resection of gastric cancer without gross or microscopic evidence of residual disease from April 1991 to December 1992, 100 patients were randomized to 6 months of 5-fluorouracil 1,000 mg/m2/day administered as continuous infusion for 5 days, cisplatin 60 mg/m2/day as intravenous infusion for 1 day with or without levamisole (50 mg every eight hours P.O for a period of three days every 2 weeks for 6 months). This chemotherapy treatment was begun within 2 to 4 weeks after the surgery. The chemotherapy consisted of discrete 5-day courses administered at 4-weeks intervals. All 100 patients are assessable.

RESULTS

The fifty patients were assigned to each treatment group. There was no statistical difference and no bias in the distribution of characteristics of the 100 evaluable patients between the two groups. A total of 274 courses of treatment were given in the levamisole group and 260 courses of treatment in non-levamisole group. Eleven patients in each group did not finish planned 6 courses of treatment mainly due to non-compliance. At median follow up of 39 months, 32 patients relapsed 19 in the levamisole group and 13 in the non-levamisole group (p = 0.284). Twenty five patients died of relapsed diseases, 15 in the levamisole group and 10 in the non-levamisole group. The levamisole group tended to show more risk of overall death rate and recurrence than the non-levamisole group. However, this result was not statistically significant at 3 years. The treatment was well tolerated in both treatment groups. The grade 2-3 toxicities were nausea/ vomiting (levamisole, non-levamisole group; 31.7%, 29.3% of treatment courses respectively), diarrhea (7.6%, 8.4%), mucositis (11.6%, 12.3%), and leukopenia (9.8%, 9.6%).

CONCLUSION

Levamisole had negative effects on disease-free survival and overall survival when added to adjuvant combination chemotherapy of cisplatin and 5-fluorouracil in patients with operable gastric cancer. Both treatment arms were generally well tolerated and the toxicity profile was similar with or without levamisole.

Conditioned response timing and integration in the cerebellum

Classical conditioning procedures instill knowledge about the temporal relationships between events. The unconditioned stimulus (US) is the event to be timed. The conditioned response (CR) is viewed as a prediction of the imminence of the US. Knowledge of the elapsed time between conditioned stimuli (CSs) and US delivery is expressed in the topological features of the CR. The peak amplitude of the CR coincides with the timing of the US. A simple connectionist network based on Sutton and Barto's Time Derivative (TD) Model of Pavlovian Reinforcement provides a mechanism that can account for and simulate CR timing in a variety of protocols. This article describes extensions of the model to predictive timing under temporal uncertainty. The model is expressed in terms of equations that operate in real time according to a competitive learning rule. The unfolding of time from the onsets and offsets of events such as CSs is represented by the propagation of activity along a sequence of time-tagged elements. The model can be aligned with anatomical circuits of the cerebellum and brain stem that are essential for learning and performance of conditioned eye-blink responses.

Purification and characterization of prophenoloxidase from the hemolymph of coleopteran insect, Holotrichia diomphalia larvae

Prophenoloxidase (pro-PO), a precursor of phenol oxidase (PO), was purified from the hemolymph of coleopteran Holotrichia diomphalia larvae. The enzyme was purified to apparent homogeneity, in six steps of chromatography, using Sephadex G-100, CM-52, Dextran-sulfate Sepharose CL-6B, Phenyl Sepharose CL-4B, Sephacryl S-200, and a Mono-Q column. The preparation exhibited a single band on SDS-PAGE. The proenzyme had a molecular weight of 158 kDa, as estimated by gel filtration. On SDS-PAGE under reducing conditions, it gave a 79 kDa band, indicating that it forms a dimer of the 79 kDa protein. On the other hand, the purified pro-PO gave two well-separated peaks, named pro-PO-1 and pro-PO-2, on reverse-phase HPLC. Amino acid compositions of both proteins were indistinguishable, thereby suggesting the presence of an allelic variant or an isoprotein. On dextran-sulfate Sepharose CL-6B chromatography, a fraction containing prophenoloxidase activating enzyme(s) (PPAE fraction), free from pro-PO, was also separated. In reconstitution experiments, the activation of purified pro-PO by PPAE fraction, was observed in the presence of 5 mM Ca2+, with a specific limited proteolysis. The NH2-terminal sequence of generated PO was determined to be NH2-Phe-Gly-Glu-Asp-Asp-. The activated PO oxidized o-diphenols but did not oxidize mono-phenol and p-diphenol substrates. The purified pro-PO was not activated by trypsin, alpha-chymotrypsin, and SDS.

In vitro antimutagenic effects of anthraquinone aglycones and naphthopyrone glycosides from Cassia tora

The antimutagenic activity of a methanol extract of Cassia tora seeds against aflatoxin B1(AFB1) was demonstrated with the Salmonella typhimurium assay. The numbers of revertants per plate decreased significantly when this extract was added to the assay system using Salmonella typhimurium TA100 and/or TA98. The MeOH extract was then sequentially partitioned with CH2Cl2, n-BuOH and H2O. The CH2Cl2 and n-BuOH fractions possessed antimutagenic activity but the H2O fraction was inactive. Neither the MeOH extract nor its fractions were capable of inhibiting the direct-acting mutagen N-methyl-N'-nitro-N-nitrosoguanidine suggesting that these fractions may prevent the metabolic activation of AFB1 or scavenge the electrophilic intermediate capable of inducing mutations. Column chromatography using silica gel yielded pure chrysophanol, chryso-obtusin, and aurantio-obtusin from the CH2Cl2 fraction and cassiaside and rubro-fusarin gentiobioside from the n-BuOH fraction. Each of these compounds demonstrated significant antimutagenic activity.

Significance of postoperative serum level of carcinoembryonic antigen (CEA) and actual half life of CEA in colorectal cancer patients

The postoperative levels of carcinoembryonic antigen (CEA) and the actual half life (T1/2) of CEA were evaluated to ascertain their potency in predicting the recurrence of colorectal cancer after curative surgery in patients who had an abnormally high level of preoperative carcinoembryonic antigen (CEA, > or = 5 ng/ml). Ninety-four patients who underwent curative surgery were enrolled and 24 patients (25.5%) had recurrence during the follow-up period (median: 30 months, range: 2-69 months). T1/2 of CEA for all patients ranged from 1.2 days to 88.1 days, with a median of 4.4 days. T1/2 of CEA (mean +/- standard deviation) was 11.7 +/- 17.9 days in recurrent patients, whereas it was 6.2 +/- 4.9 days in patients without recurrence (p = 0.0224). The patients' age, gender, size of the tumor, location of the tumor, pre-, and postoperative CEA level, pathologic type of the tumor and Dukes stage had no significance in recurrence. The 1-year, 2-year, and 5-year disease-free survival rates were 95.1%, 81.1%, and 73.8% in patients with postoperative CEA levels less than 5 ng/ml (n = 62), respectively, and 71.4%, 64.8%, and 64.8% in patients with postoperative CEA levels higher than or equal to 5 ng/ml (n = 32), respectively (p = 0.04). Patients were divided into Group S (T1/2 of CEA < 4.4 days, n = 43) and Group L (T1/2 of CEA > or = 4.4 days, n = 51). The 1-year, 2-year, and 5-year disease-free survival rates were 95.3%, 85.1%, and 77.7% in Group S, respectively, and 80%, 67.5%, and 64.1% in Group L, respectively (p = 0.0261). In conclusion, the disease-free survival of colorectal cancer patients was prolonged in patients who had a short T1/2 of CEA or a low level of postoperative CEA. In high-risk colorectal cancer patients with an abnormally high level of preoperative CEA, recurrence may be predicted by checking an early postoperative CEA level and/or by a simple calculation of the actual half life of CEA.

Adenomyoepithelioma of the breast--its diagnostic problems and histogenesis

We report three cases of adenomyoepithelioma of the breast that occurred in middle aged women. The tumor is characterized by a balanced proliferation of epithelial tubules and surrounding myoepithelial cells that are spindle shaped or have clear cytoplasms. The first case mimicked tubular adenoma in the initial biopsy. However, on excision it turned out to be an adenomyoepithelioma of the tubular. The other two cases were lobulated types and had fibroadenomatous areas. The morphologic appearance of this tumor varies, making it misleading to other benign or even malignant lesions. The tumor has a potential for local recurrence, therefore, wide excision is recommended for proper diagnosis and treatment.

Nodal metastasis in the distal mesorectum: need for total mesorectal excision of rectal cancer

Locoregional failure of rectal cancer is a troublesome problem and a major cause of morbidity and mortality following curative surgery. The mesorectum has been regarded as an important site in local failure after surgery of rectal cancer. Total mesorectal excision (TME) has been raised by some colorectal surgeons to prevent early local recurrence. This study was performed to ascertain the incidence of metastatic lymph nodes in the distal mesorectum (DMR) of the colorectal cancer patient. We also examined the clinicopathologic risk factors of distal mesorectal metastasis. Eight of 53 patients had positive metastatic lymph nodes in DMR. Twenty-seven patients were Dukes B and 26 patients were Dukes C stage. Out of 26 Dukes C patients, 8 patients (30.8%) had metastatic lymph nodes in the DMR. However, there was no significant difference in risk factors between DMR positive and DMR negative patients with Dukes C stage. In conclusion, the incidence of metastatic lymph nodes in DMR was about 30.8%, therefore the mesorectum especially the DMR should be removed completely by total mesorectal excision to eradicate the metastatic lymph nodes which may cause local recurrence.

Thermal balance of man in water: prediction of deep body temperature change

Changes in rectal temperature and metabolic rate were continuously monitored in men immersed in water at 15, 20, 25, 30, and 35 degrees C. The subjects (12 healthy male students) wore swimming suits while either resting or doing leg exercise (delta M approximately 60 kcal.h-1.m-2 approximately 70 W.m-2) for 1 h. At all water temperatures below 30 degrees C, the metabolic rate increased but the rectal temperature fell continuously, resulting in hypothermia. The rate of fall in rectal temperature (cooling rate, CR, degrees C.h-1) was inversely proportional to water temperature (Tw, degrees C) according to the equation CR = 3.818-0.109 Tw in resting subjects and CR = 3.434-0.110 Tw in exercising subjects. At a given Tw the cooling rate was greater in resting than in exercising subjects and in lean than in obese subjects. From the relationships between the cooling rate and water temperature the duration of useful activity and the survival time were predicted for resting and exercising subjects of various fatness.

Solid and papillary neoplasms of the pancreas

Solid and papillary neoplasms of the pancreas, a rare tumor usually found in young female patients, seldom presents with metastasis since it is a tumor with low potential for malignancy. The prognosis for this lesion is much more favorable than that for other pancreatic neoplasms. In an attempt to understand the characteristics and prognosis of this lesion, we reviewed twenty cases treated at the Department of Surgery, Severance Hospital, Yonsei University from 1985 to 1994. The mean age of the patients was 25.6 years (range: 13 to 39 years), and 19 (95%) were women. Chief complaints were palpable mass (50%), pain (45%), and indigestion (5%). In laboratory studies, tumor markers, including CEA, CA125, CA19-9, and aFP were studied in eight patients, and found negative. Other laboratory findings were also nonspecific. These tumors may occur anywhere in the pancreas. In our studies, the tumor was most often located in the tail (45%), and the head (40%) of the pancreas. These were treated by distal pancreatectomy and splenectomy (55%), Whipple's operation (20%), pylorus preserving pancreatoduodenectomy (10%), enucleation (10%) or excision (5%). Significant morbidity or mortality was not observed during hospitalization, and no recurrence or malignant degeneration occurred during the mean follow-up period of 4 years (range: 1 month to 9 years). In conclusion, this study has suggested that the patients with a solid and papillary neoplasm of the pancreas have a good prognosis for successful treatment, if the disease is diagnosed early and the tumor is completely resected. A higher index of suspicion, and more aggressive diagnostic workups are needed in dealing with this disease entity.

Veno-occlusive disease (VOD) of the liver in Korean patients following allogeneic bone marrow transplantation (BMT): efficacy of recombinant human tissue plasminogen activator (rt-PA) treatment

Veno-occlusive disease (VOD) of the liver is a clinical syndrome characterized by hyperbilirubinemia, painful hepatomegaly, and fluid retention. In the bone marrow transplantation (BMT) setting, VOD is caused by dose-intensive chemotherapy and/or radiotherapy used to prepare patients for transplant. VOD occurs in up to 50% of the patients who undergo BMT and is usually associated with a high mortality rate. Until recently, there was no proven effective medical therapy for this condition once it was clinically apparent. We report here on the frequency and treatment result of VOD with rt-PA in our allogeneic BMT patients. Eight patients (median age 28.5 years) underwent allogeneic BMT from December, 1993 to June, 1995 in Asan Medical Center. Six leukemia patients were prepared for BMT with busulfan and cyclophosphmide, while two aplastic anemia patients received cyclophosphamide and antithymocyte globulin. VOD was defined as having two of the following features before day 20 posttransplant: jaundice (bilirubin > or = 2 mg/dL), tender hepatomegaly and/or right upper quadrant pain, ascites and/or unexplained weight gain (> 2% from baseline). All patients who were diagnosed with VOD received rt-PA (10-20 mg/day) and heparin (10,000 U/day). Three (37.5%) of the eight patients developed VOD that occurred between 6 and 10 days posttransplant. All three patients developed jaundice, weight gain, and tender hepatomegaly. Ascites and renal insufficiency occurred in two patients and pleural effusion in one patient. rt-PA and heparin were begun 6 to 26 days posttransplant and rt-PA was administered for 7 to 14 days. All three patients responded to the therapy; bilirubin levels began to decrease at 4 to 13 days from the start of therapy. They are all alive at day 111, 316, and 548 days posttransplant. None of the patients had significant hemorrhagic complications after rt-PA treatment. Prolonged administration of rt-PA was feasible without bleeding episode and it seems that rt-PA may alter the natural course of VOD.

Ownership Form and Quality of Care in Sheltered Care Facilities: Chain-Affiliated Business vs. Sole Proprietorship

Mental health services are increasingly provided by private-for-profit organizations that are chain-affiliated businesses. The effect of this trend on quality of care is a growing concern. Sheltered care facilities (board and care, family care, and psychosocial rehabilitation facilities) servicing upwards of 400,000 (Goldman, Gattozzi, & Taube, 1981) seriously mental ill nationwide provide the lowest level of 24-hour supervised care to this population. This study explores the quality of care in 145 sheltered care facilities in California. Contrasts were made between 108 sole proprietorships and 37 chain-affiliated business facilities on several quality of care measures. Chain-affiliated businesses had poorer physical characteristics, higher costs, less experienced staff, and were more likely to be located in minority and lower class neighborhoods. Much of the negative stereotypes of chain-affiliated businesses were documented in our sample.

The force-velocity curve in passive whole muscle is asymmetric about zero velocity

The force-velocity property of passive muscle was investigated to determine if a discontinuity of slope occurred at zero velocity. Isolated, unstimulated whole frog sartorius muscles were subjected to constant-velocity stretches and releases using a servo-controlled lever. The force due to damping (delta T) was calculated by subtracting the tension measured at a very low speed (1.0 mm s-1) from the tension measured at the same length while the muscle was shortening or lengthening at a particular test speed. The experiments were performed over a range of speeds at each of several lengths and at two temperatures. For comparison, the same experiments were performed using a strip of pure latex rubber and a steel spring. Curves showing the magnitude of delta T vs velocity were nearly symmetric about the zero-velocity axis for the steel spring and the rubber strip, but were markedly asymmetric for passive muscle, showing a positive delta T for lengthening at all speeds that was between four and 11 times the negative delta T for shortening at the same speed, depending on the temperature and initial stretch length. The force due to damping at a given speed increased with extension above the rest length in passive muscle but decreased with increasing length in experiments using the latex strip. Predictions obtained from a mathematical model based on a damping element in series with a lightly damped spring were fitted to the experimental measurements of delta T vs velocity. The damping parameter provisionally representing interfilamentary sliding was between six and 12 times larger for lengthening than for shortening.(ABSTRACT TRUNCATED AT 250 WORDS)

Conformation and function of the N-linked glycan in the adhesion domain of human CD2

The adhesion domain of human CD2 bears a single N-linked carbohydrate. The solution structure of a fragment of CD2 containing the covalently bound high-mannose N-glycan [-(N-acetylglucosamine)2-(mannose)5-8] was solved by nuclear magnetic resonance. The stem and two of three branches of the carbohydrate structure are well defined and the mobility of proximal glycan residues is restricted. Mutagenesis of all residues in the vicinity of the glycan suggests that the glycan is not a component of the CD2-CD58 interface; rather, the carbohydrate stabilizes the protein fold by counterbalancing an unfavorable clustering of five positive charges centered about lysine-61 of CD2.

Mycetoma caused by Acremonium falciforme: successful treatment with itraconazole

Mycetoma has not been previously reported in Korea. A case of mycetoma caused by Acremonium falciforme in a 72-year-old man is described. The patient had a single, large, well-demarcated, erythematous, swollen, black, escharlike lesion and three small satellite lesions on his right temporal area. He was treated with itraconazole, and all lesions healed with residual scars in 70 days.

Composition and sequence specific resonance assignments of the heterogeneous N-linked glycan in the 13.6 kDa adhesion domain of human CD2 as determined by NMR on the intact glycoprotein

CD2, a T cell specific surface adhesion receptor, is critically important for T lymphocytes to mediate their regulatory and effector functions. The amino terminal domain of human CD2 is responsible for cell adhesion, binding to CD58 on antigen-presenting cells or target cells. This adhesion domain in human CD2 contains a single high-mannose N-glycan. This carbohydrate or part of it appears to be required to maintain the native conformation of the polypeptide and its ability to bind CD58. To better understand the structural aspects that regulate human CD2 adhesion functions, we had previously determined the solution structure of the protein part of the N-glycosylated adhesion domain of human CD2 (hu-sCD2(105); MW approximately 13.6 kDa) by NMR spectroscopy. Here, we have identified protein--carbohydrate and carbohydrate--carbohydrate interactions and, in combination with previous knowledge from electrospray ionization mass spectrometry, have determined the composition of the heterogeneous high-mannose glycan in hu-sCD2(105). These contacts clearly define the carbohydrate's orientation with respect to the protein. The NMR data further suggest that one arm of the glycan is folded toward the trisaccharide core consisting of GlcNAc1-GlcNAc2-Man3. A detailed comparison between chemical shift data of free model oligosaccharides with those of the glycomers present in our hu-sCD2(105) sample reveals that only the resonances of the two GlcNAc residues are significantly different from those of free high-mannose glycans. This work was based on a new strategy to achieve sequential assignments of the 1H and 13C resonances of the heterogeneous high-mannose carbohydrate [(Man)nGlcNAc2, n = 5-8] in hu-sCD2(105) on the intact glycoprotein using a combination of homonuclear 1H-1H and heteronuclear 1H-13C NMR experiments at natural abundance.

Alaternin, cassiaside and rubrofusarin gentiobioside, radical scavenging principles from the seeds of Cassia tora on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical

Radical scavenging principles on 1,1-diphenyl-2-picrylhydrazyl(DPPH) radical were isolated from the seeds of Cassia tora L. Assignments of the 1H- and 13C-NMR data showed the active components to be an anthraquinone, alaternin and two naphthopyrone glycosides, nor-rubrofusarin-6-beta-D-glucoside(cassiaside) and rubrofusarin-6- -D-gentiobioside. Alaternin showed more potent radical scavenging effect than the others.

Transrectal ultrasonography in preoperative staging of rectal cancer

A precise knowledge of the depth of invasion of tumor is essential for the planning of treatment of rectal cancer. Transrectal ultrasonography is a new diagnostic modality that has become useful in determining the depth of invasion preoperatively and the presence or absence of metastatic lymph nodes. Transrectal ultrasonography was used in preoperative staging of 36 patients with rectal cancer. Thirty three patients had a radical resection (17 low anterior resection, 15 abdominoperineal resection and 1 pelvic exenteration), one patient had a local excision. Two among these thirty four patients had preoperative radiotherapy. Preoperative transrectal ultrasonographic staging was compared with pathologic findings. In staging depth of invasion, the overall accuracy was 88.8 percent, overstaged in 5.8 percent, understaged in 5.8 percent. Transrectal ultrasonography is the more accurate method than CT in staging of depth of tumor invasion (61.8% vs 88.8%). In staging of lymph nodes, the overall accuracy of transrectal ultrasonography was 85.3 percent, sensitivity was 71.7 percent and specificity was 88.8 percent. Transrectal ultrasonography is a safe, inexpensive and accurate staging method in the assessment of both depth of invasion and nodal status.

Stability of piperacillin sodium-tazobactam sodium and ranitidine hydrochloride in 0.9% sodium chloride injection during simulated Y-site administration

The stability of piperacillin sodium plus tazobactam sodium and ranitidine hydrochloride in 0.9% sodium chloride injection during simulated Y-site administration was studied. Triplicate test solutions of piperacillin 40 mg/mL plus tazobactam 5 mg/mL (as the sodium salts) or piperacillin 80 mg/mL plus tazobactam 10 mg/mL (as the sodium salts) were mixed 1:1 with ranitidine 0.5 and 2.0 mg/mL (as the hydrochloride salt). The solutions were stored at 23 degrees C, and samples were removed at zero, one, two, and four hours for measurement of drug concentration by stability-indicating high-performance liquid chromatography. At the time of sampling and before any dilution, each sample was visually inspected for color and precipitation, and pH was determined. At all sampling times, the concentrations of piperacillin, tazobactam, and ranitidine were > 90% of initial concentrations. There were no substantial changes in pH or color. Tazobactam 5 mg/mL (as the sodium salt) and ranitidine 0.5 and 2 mg/mL (as the hydrochloride salt) in 0.9% sodium chloride injection were stable for up to four hours during simulated Y-site administration. Piperacillin 80 mg/mL plus tazobactam 10 mg/mL (as the sodium salts) and ranitidine 0.5 and 2 mg/mL (as the hydrochloride salt) were stable for up to four hours during simulated Y-site administration.

Antimutagenic effect of plant flavonoids in the Salmonella assay system

The antimutagenic effects of 27 kinds of plant flavonoids on the mutagenicity of aflatoxin B1(AFB1) and N-methyl-N'-nitro-N-nitrosoguanidine(MNNG) in Salmonella typhimurium TA100 were investigated. In the mixed applications of AFB1 (1 microgram/plate) with the flavonoids (300 micrograms/plate) in the presence of a mammalian metabolic activation system (S9 mix), chrysin, apigenin, luteolin and its glucoside, kaempferol, fisetin, morin, naringenin, hesperetin, persicogenin, (+)-catechin and (-)-epicatechin showed the antimutagenic effect against AFB1 with more than 70% inhibition rate. A little or no antimutagenicities except flavone against MNNG (0.5 microgram/plate) were observed. For the antimutagenicity of the flavonoids on AFB1, the flavonoid structure that contains the free 5-, 7-hydroxyl group seemed to be essential. However, saturation of the 2,3-double bond or elimination of the 4-keto group did not affect the activity.