The green tea polyphenol (-)-epigallocatechin gallate attenuates beta-amyloid-induced neurotoxicity in cultured hippocampal neurons

Previous evidence has indicated that the neuronal toxicity of amyloid beta (betaA) protein is mediated through oxygen free radicals and can be attenuated by antioxidants and free radical scavengers. Recent studies have shown that green tea polyphenols reduced free radical-induced lipid peroxidation. The purpose of this study was to investigate whether (-)-epigallocatechin gallate (EGCG) would prevent or reduce the death of cultured hippocampal neuronal cells exposed to betaA because EGCG has a potent antioxidant property as a green tea polyphenol. Following exposure of the hippocampal neuronal cells to betaA for 48 hours, a marked hippocampal neuronal injuries and increases in malondialdehyde (MDA) level and caspase activity were observed. Co-treatment of cells with EGCG to betaA exposure elevated the cell survival and decreased the levels of MDA and caspase activity. Proapoptotic (p53 and Bax), Bcl-XL and cyclooxygenase (COX) proteins have been implicated in betaA-induced neuronal death. However, in this study the protective effects of EGCG seem to be independent of the regulation of p53, Bax, Bcl-XL and COX proteins. Taken together, the results suggest that EGCG has protective effects against betaA-induced neuronal apoptosis through scavenging reactive oxygen species, which may be beneficial for the prevention of Alzheimer's disease.

The effects of a selective noradrenaline reuptake inhibitor on the urethra: an in vitro and in vivo study

OBJECTIVE

To identify the effects of a selective noradrenaline reuptake inhibitor (venlafaxine) on urethral perfusion pressure (UPP) in rabbits and rats, and thus assess its therapeutic potential for treating stress urinary incontinence.

MATERIALS AND METHODS

Strips of bladder and proximal urethra were prepared from female New Zealand White rabbits. Each strip was electrically stimulated and the contractile responses of controls strips compared with those after pretreatment with venlafaxine (100 micromol/L). In separate experiments using 80 adult female Sprague-Dawley rats (250-300 g), changes in intravesical pressure and UPP after the intra-arterial and intra-urethral administration of phenylephrine, phentolamine, fluoxetine and venlafaxine were monitored using double-lumen catheters.

RESULTS

Pretreatment with venlafaxine significantly decreased the contraction of bladder strips (P=0.01) and significantly increased the contraction of urethral strips (P=0.008). In vivo, phenylephrine administered by both routes significantly increased UPP (P=0.02); phentolamine (arterial) significantly decreased UPP (P=0.001); fluoxetine (arterial) had no effect on UPP, and venlafaxine (both routes) significantly increased UPP (both P<0.001). The intravesical pressure was not changed significantly in any animal.

CONCLUSIONS

Venlafaxine effectively increased UPP both in vitro and in vivo; these results imply that venlafaxine may be useful for treating stress urinary incontinence, by increasing the UPP.

Acute actions of tumor necrosis factor-alpha on intracellular Ca(2+) and K(+) currents in human microglia

The effects of acute application of the pro-inflammatory cytokine tumor necrosis factor-alpha (TNFalpha) on levels of intracellular Ca(2+) ([Ca(2+)]i) and on whole-cell outward and inward K(+) currents were studied in cultured human microglia. TNFalpha elicited a linear increase in [Ca(2+)]i to a plateau level in microglia bathed in either standard physiological saline solution or Ca(2+)-free physiological saline solution. The rate of increase of [Ca(2+)]i or the level of [Ca(2+)]i attained was not significantly altered in the absence of external Ca(2+) indicating that Ca(2+) influx did not contribute appreciably to the cytokine-induced rise in [Ca(2+)]i. This point was directly confirmed using Mn(2+) quenching where no change in signal fluorescence was observed with TNFalpha treatment of microglia in Ca(2+)-free physiological saline solution. The rate of increase of [Ca(2+)]i induced by TNFalpha in Ca(2+)-free physiological saline solution was not altered by prior application of ATP to deplete inositol triphosphate stores indicating that these stores did not contribute to the cytokine response. In whole-cell patch clamp recordings, the acute treatment of human microglia with TNFalpha led to the expression of an outward K(+) current in one-third (14 of 41) of cells. This current was activated at potentials positive to -30 mV, showed rapid kinetics of activation with no evident inactivation and had an I-V relation exhibiting outward rectification. Analysis of tail currents showed reversal of the outward K(+) current near -70 mV and tetraethylammonium (10 mM) inhibited the outward K(+) current to 24% of control level. Acute application of TNFalpha had no effect to alter inward rectifier currents generated from voltage ramps. The signaling pathways involving TNFalpha modulation of [Ca(2+)]i and K(+) channels in human microglia may contribute to functional and pathological actions of the cytokine in the brain.

Impact of postprandial hypertriglyceridemia on vascular responses in patients with coronary artery disease: effects of ACE inhibitors and fibrates

We analyzed vascular responses (endothelial function, oxidant stress) to postprandial hypertriglyceridemia (PHTG) in patients with coronary artery disease (CAD) to reveal potential therapeutical effects of angiotensin converting enzyme inhibition (ACE-I) and of lipid lowering (fibrate). The study population (n=39, mean age: 60 years) consisted of four groups, all of which had angiographically documented CAD. A high fat group (n=9) consumed a high fat meal, a low fat group (n=9) a low fat meal, and ACE-I (n=10) or fibrate (n=11) groups consumed a high fat meal plus lisinopril or fenofibrate. Serum triglycerides (TG) increased significantly 2 h after eating a test meal in all groups with the exception of the low fat group. In the high and low fat groups changes of serum TG were positively correlated (r=0.664, P<0.005) with changes of phorbol ester-activated leukocyte superoxide anion radical (O(2-.)) formation and were negatively correlated (r=-0.488, P<0.05) with flow-mediated brachial artery dilation (FMD). There was a negative correlation (r=-0.419, P=0.094) between FMD and changes of O(2-.) formation in the high and low fat groups. In the ACE-I and fibrate groups, O(2-.) formation decreased 2 h after eating a test meal (from 5.34+/-1.01 to 3.81+/-1.15 nmol/10(6)cells per min, P<0.01, and from 4.66+/-0.91 to 4.26+/-0.97 nmol/10(6)cells per min, P=0.374, respectively). However, endothelial function did not show any significant changes 2 h after eating a test meal in all groups. PHTG increases oxidant stress and further deteriorates endothelial function, even in patients with CAD. Both ACE-I and fibrates have an antioxidant effect but no acute beneficial effects in terms of endothelial function under conditions of PHTG in CAD patients.

Noninvasive evaluation of endothelial function

Endothelial dysfunction is generally believed to be the inciting event in atherosclerosis, and is probably important in ischemic manifestations as well. The release of endothelium-derived vasoactive substances is not only triggered by acetylcholine, but also controlled by a host of neuromediators and by shear forces exerted by the blood flowing through the blood vessel. However, this balance is altered in disease states such as atherosclerosis, diabetes, chronic heart failure, coronary artery disease, or hypertension. The most important mechanism in the decrease in endothelium-dependent relaxation appears to be a reduced release of nitric oxide. In healthy people, the predominant effect of stimulation of the endothelium is vasodilation. It is tempting to hypothesize that endothelial dysfunction is one of the initial steps involved in the development of atherosclerosis, but also in peripheral artery atherosclerosis. Impairment of endothelium-dependent vasodilation in the coronary arteries has been demonstrated not only in patients with documented atherosclerosis and/or established cardiovascular risk factors. Noninvasive evaluation of brachial artery vasoactivity using high resolution B-mode ultrasound is currently being established to evaluate endothelial function. We studied the endothelial function in 50 normal volunteers, 28 hypertensive subjects, and 31 hypercholesterolemia subjects. The diameter of the target artery was measured from two-dimensional ultrasound images with 10 MHz linear transducer. The results suggested that antihypertensive therapy with a certain calcium antagonist did not have a favorable effect on endothelial function and after cessation of cholesterol lowering therapy, the endothelial dysfunction developed again. The endothelial function can now be readily measured in humans and is very useful research tool to assess the effect of risk factors and their treatment on vascular function. Endothelial function testing will assume a prominent role in the evaluation and treatment of patients at risk of developing coronary atherosclerosis and its sequelae.

Proteins with beta-(thienopyrrolyl)alanines as alternative chromophores and pharmaceutically active amino acids

L-beta-(Thieno[3,2-b]pyrrolyl)alanine and L-beta-(thieno[2,3-b]pyrrolyl)alanine are mutually isosteric and pharmaceutically active amino acids that mimic tryptophan with the benzene ring in the indole moiety replaced by thiophene. Sulfur as a heteroatom causes physicochemical changes in these tryptophan surrogates that bring about completely new properties not found in the indole moiety. These synthetic amino acids were incorporated into recombinant proteins in response to the Trp UGG codons by fermentation in a Trp-auxotrophic Escherichia coli host strain using the selective pressure incorporation method. Related protein mutants expectedly retain the secondary structure of the native proteins but show significantly changed optical and thermodynamic properties. In this way, new spectral windows, fluorescence, polarity, thermodynamics, or pharmacological properties are inserted into proteins. Such an engineering approach by translational integration of synthetic amino acids with a priori defined properties, as shown in this study, proved to be a novel and useful tool for protein rational design.

Incorporation of beta-selenolo[3,2-b]pyrrolyl-alanine into proteins for phase determination in protein X-ray crystallography

beta-Selenolo[3,2-b]pyrrolyl-L-alanine that mimics tryptophan with the benzene ring of the indole moiety replaced by selenophene, was incorporated into human annexin V and barstar. This was achieved by fermentation and expression in a Trp-auxotrophic Escherichia coli host strain using the selective pressure incorporation method. The seleno- proteins were obtained in yields comparable to those of the wild-type proteins and exhibit full crystallographic isomorphism to the parent proteins, but expectedly show altered absorbance profiles and quenched tryptophan fluorescence. Since the occurrence of tryptophan residues in proteins is rare, incorporation of the electron-rich selenium-containing tryptophan surrogate into proteins represents a useful supplementation and even a promising novel alternative to selenomethionine for solving the phase problem in protein X-ray crystallography.

Anticoagulant activity of sulfoalkyl derivatives of curdlan

Curdlan is a natural beta-1,3-glucan produced by Agrobacterium biovar 1. In this study, the anticoagulant activity of sulfoalkyl derivatives of curdlan was investigated by carrying out activated partial thromboplastin time (APTT) assay and compared with that of o-sulfonated curdlan. Approximately 100-fold higher concentration of o-sulfonated curdlan than heparin was required to obtain the same level of the clotting time. Anticoagulant activity of curdlan derivatives was dependent on the degree of sulfation in prolonging the clotting time. However, the chain length of the substituent did not play a role in prolonging the clotting time. The curdlan derivatives enhanced thrombin inhibition by mediating through antithrombin III. The inhibition of thrombin by o-sulfonated curdlan was found to be approximately 10-fold weaker than that by heparin.

Postprandial hypertriglyceridemia impairs endothelial function by enhanced oxidant stress

AIMS

it appears that hypertriglyceridemia (HTG) is a risk factor of atherosclerosis as demonstrated by recent studies. In this study, we analyzed the effects of acute HTG on endothelial function and oxidative stress, which are important mechanisms in the pathogenesis of atherosclerosis.

METHODS AND RESULTS

in a high fat meal group (n = 11), serum triglycerides and PMA-activated leukocyte O(2)(-)* production were significantly (P < 0.005) increased from 146 +/- 69 mg/dl and 4.09 +/- 0.93 nmol/10(6) cells/min preprandially to 198 +/- 88 mg/dl and 5.49 +/- 1.19 nmol/10(6) cells/min, respectively, 2 h after eating a high-fat meal. The flow-mediated endothelium-dependent brachial artery dilation (FMD; high-resolution ultrasound) was decreased from 13.7 +/- 3.3% preprandially to 8.2 +/- 3.7%, 2 h after eating a high-fat meal (P < 0.005). However, following a low-fat meal (n = 9), there were no significant changes in triglycerides, leukocyte O(2)(-)* production and FMD. Changes of serum triglycerides were correlated negatively (r = -0.650, P < 0.005) with changes of FMD, but were correlated positively (r = 0.798, P < 0.001) with changes of leukocyte O(2)(-)* production, which - in turn - were correlated negatively (r = -0.784, P < 0.001) with changes of FMD in all study subjects (mean age: 56 years, n = 20).

CONCLUSIONS

this study suggests that acute HTG causes endothelial dysfunction via enhanced oxidant stress and this may pave the way for the development of atherosclerosis under chronic conditions.

Expression of Fas and Fas-related molecules in human hepatocellular carcinoma

Many tumor cells, including hepatocellular carcinoma (HCC), express both Fas and its ligand on their surfaces, and it has remained a mystery why such cells do not spontaneously become apoptotic. In the current study, we analyzed the alterations of Fas structure and the expression of Fas and Fas ligand (FasL) and of Fas pathway inhibitors, including soluble Fas (sFas), Fas-associated phosphatase-1 (FAP-1), and bcl-2, in 50 cases of human HCC. Monoallelic loss of the Fas gene, as determined by loss of heterozygosity with intragenic polymorphisms, was observed in 5 of the 34 informative cases (15%), but none of the 50 cases showed Fas gene mutation. Expression of Fas and FasL was detected in 44 (88%) and 50 (100%) cases, respectively. sFas messenger RNA, as analyzed by in situ reverse-transcription polymerase chain reaction was expressed in 42 of the 50 cases (84%), and FAP-1 expression was observed in 40 of the 50 cases (80%). In contrast, none of the 50 cases showed bcl-2 expression. Our results showed that the majority of the HCCs (88%) coexpressed a death receptor, Fas and its cognate ligand, FasL, but all HCCs showed one or more alterations of the Fas pathway molecules known to inhibit Fas-mediated apoptosis. These findings suggest that the expression of sFas and FAP-1 and, in part, loss of Fas expression, rather than Fas gene alteration or bcl-2 expression, may be involved in the Fas resistance of HCC in vivo and that these mechanisms may play important roles in the pathogenesis of human HCC. HUM PATHOL 32:250-256.

High-resolution confocal detection of nanometric displacement by use of a 2 x 1 optical fiber coupler

A novel high-resolution confocal measurement of nanometric displacement that uses a simple 2 x 1 optical fiber coupler is presented. The basic principle is to detect interferometrically the change in the phase difference between two adjacent input fibers of the coupler that results from the nonuniform wave-front curvature of the reflected light. Measurement of subnanometer axial modulation, which permits high-resolution displacement sensing by optical means, is demonstrated.

Gap measurement by position-sensitive detectors

A system for measuring the gap in a proximity exposure tool of a plasma display panel (PDP) is developed that uses single or dual position-sensitive detectors (PSD's). The resolution of the gap distance is 0.5 mum, with a capture range of 500 mum. Signal processing is simple and fast and easy because analogous PSD's are used as the position sensors. One PSD is used to detect the position of the reference beam, which is reflected from the upper surface of the gap; the other PSD is used to detect the position of the signal beam, which is reflected from the lower surface of the gap. A charge-coupled-device sensor is also employed to monitor the reflected beams and the region of measurement. In the gap-measurement system that uses a single PSD, first the reference beam is incident upon the PSD and then the signal beam is incident upon the same PSD. Then the separation between the two beams is calculated from the position of the reference beam and from the average beam position.

Role of metabolic activation by cytochrome P450 in thioacetamide-induced suppression of antibody response in male BALB/c mice

Effects of thioacetamide on antibody response to sheep red blood cells were investigated in male BALB/c mice. When mice were treated intraperitoneally with thioacetamide once, the antibody response was significantly suppressed at 200 mg/kg with hepatotoxicity. When mice were treated intraperitoneally with thioacetamide for 7 consecutive days, the antibody response was suppressed at 50 mg/kg without hepatotoxicity. To determine the possible role of metabolic activation by cytochrome P450 in thioacetamide-induced suppression of antibody response, mice were pretreated with phenobarbital intraperitoneally for 3 days, followed by intraperitoneal administration of 100 mg/kg of thioacetamide for 3 days. The elevated activities of serum aspartate aminotransferase and alanine aminotransferase by thioacetamide were potentiated by phenobarbital pretreatment. The suppression of antibody response by thioacetamide was potentiated by phenobarbital. In liver microsomes, the activities of P450 2B-specific enzymes were induced by phenobarbital. Our present results suggest that thioacetamide may require metabolic activation by P450 to its immunosuppressive form(s).

Evidence of enhancement of malate-aspartate shuttle activity in beta cells of streptozotocin-induced non-insulin-dependent diabetic rats

Glucose-induced insulin secretion is selectively impaired in beta cells from animals with non-insulin-dependent diabetes mellitus (NIDDM). This study was performed to clarify whether the malate-aspartate shuttle among the glucose metabolic pathways is intact in beta cells of NIDDM rats. The insulin secretory capacity of the islets and the K(ATP) channel activity in single beta cells were measured in control and NIDDM rats injected with streptozotocin (STZ) during the neonatal period, using a radioimmunoassay and patch-clamp technique. The increase of insulin secretion induced by 11.1 mmol/L glucose or 10 mmol/L dihydroxyacetone (DHA) was significantly reduced in NIDDM islets, suggesting an impaired glycerol-phosphate shuttle. The application of glyceraldehyde (10 mmol/L) in NIDDM or control islets elicited an increase in insulin secretion, but the difference between the 2 groups was indistinguishable. On the contrary, the increase of insulin secretion and the inhibition of K(ATP) channel activity induced by aspartate, which preferentially participates in the malate-aspartate shuttle, were significantly greater in NIDDM versus the control. However, intracellularly applied aspartate in the inside-out mode did not inhibit K(ATP) channel activity. These findings show that malate-aspartate shuttle activity is potentiated in pancreatic beta cells of NIDDM rats, suggesting the development of a compensatory mechanism for the reduced activity of the glycerol-phosphate shuttle in NIDDM.

Platelet-activating factor induced Ca(2+) signaling in human microglia

Increases in intracellular Ca(2+) concentration in human microglial cells in response to platelet-activating factor (PAF) were studied using Ca(2+)-sensitive fluorescence microscopy. In normal physiological solution (PSS), PAF-induced transient increases in [Ca2+](i) which recovered to baseline values within 200 s. Application of PAF in zero-Ca(2+) solution caused the peak response to be decreased to a value near 20% of that recorded in PSS suggesting a primary contribution of Ca(2+) influx for the [Ca2+](i) increase in PSS. To investigate PAF-induced Ca(2+) influx, the contents of intracellular stores were modulated using the SERCA blocker cyclopiazonic acid (CPA). The Ca(2+) signal induced by CPA (10 microM) in zero-Ca(2+) solution showed a peak response about 20% of the amplitude in the presence of external Ca(2+), suggesting the latter response included significant contributions from store-operated Ca(2+) entry. The influx of divalent cations with PAF or CPA was directly measured using Mn(2+) quenching of the fluorescence signal. Although both PAF and CPA induced a similar degree of Mn(2+) influx over time, the PAF effect was very rapid, whereas the CPA action was delayed and only evident about 200 s after application. Overall, the results show that the primary source of the PAF-induced increase of [Ca2+](i) in human microglia was the influx of Ca(2+) from the extracellular space and intracellular Ca(2+)-release contributed only a small part of the total Ca(2+) signal. Nevertheless, Ca(2+)-release induced by PAF (or CPA) serves as an important factor in controlling Ca(2+) entry presumably mediated by activation of store-operated-Ca(2+) channels.

Long-distance PCR-based screening for large rearrangements of the LDL receptor gene in Korean patients with familial hypercholesterolemia

BACKGROUND

The LDL receptor is a cell-surface protein that regulates plasma cholesterol by specific uptake of LDL particles from the blood circulation. Familial hypercholesterolemia (FH) results from defective catabolism of LDL, which is caused by mutations in the LDL-receptor gene.

METHODS

For the rapid and reliable detection of large rearrangements in the LDL-receptor gene, we established a screening method based on long-distance PCR as an alternative to Southern-blot hybridization. Using long-distance PCR, 45 unrelated Korean subjects heterozygous for FH were screened to assess the frequency and nature of major structural rearrangements in the LDL-receptor gene.

RESULTS

Two different deletion mutations, FH6 (same type as FH3 and FH311) and FH 32, were detected in four families by long-distance PCR. Detailed restriction mapping and sequence analysis showed that FH6 was a 5.71-kb deletion extending from intron 8 to intron 12 and that FH32 was a 2-kb deletion extending from intron 6 to intron 7. Sequence analysis for the breakpoints of all deletions detected in Korean FH patients showed that only the left arms of the Alu repetitive sequences were involved in the deletion event.

CONCLUSIONS

The screening method based on long-distance PCR provides a powerful strategy for the detection of large rearrangements in the LDL-receptor gene and is a rapid and reliable screening alternative to Southern-blot hybridization.

Topically applied betaxolol attenuates NMDA-induced toxicity to ganglion cells and the effects of ischaemia to the retina

The present results show that topically applied Betoptic(R)(0.5% betaxolol) to the rabbit or rat eye reaches the retina and can counteract the detrimental effects caused by ischaemia/reperfusion or N -methyl- d -aspartate (NMDA)-induced insults to the retina. Betaxolol is a beta(1)-adrenergic blocker but its neuroprotective action is generally thought to be due to its calcium channel blocking properties. Support for this view comes from studies on cultures of cortical neurones where it was found that betaxolol attenuated the NMDA-induced influx of(45)Ca(2+)while beta-adrenoreceptor agonists were ineffective. Topically applied Betoptic(R)to the rabbit eye was observed to reach the retina in maximal amounts within 60 min. Some of the substance was also found in the contralateral retina of the untreated eye suggesting that the agent reaches the retina by local systemic and retinal circulation. Concurrent treatment with Latanoprost(R)did not result in a greater amount of betaxolol reaching the retina. An ophthalmodynamometric procedure, which raises the intraocular pressure, was used to apply an ischaemic insult to the rabbit retina. After three days of reperfusion the b-wave of the electroretinogram was reduced by an average of 59% and the choline acetyltransferase immunoreactivity in the retina was almost obliterated. However, when experiments were carried out on animals which had been treated with one drop of Betoptic(R) twice daily for 4 weeks before ischaemia and also during the reperfusion phase, the reductions in both the b-wave of the electroretinogram and retinal choline acetyltransferase immunoreactivity due to ischaemia/reperfusion were greatly attenuated. Intravitreal injection of NMDA into the rat eye caused a decrease in the immunostaining for Thy-1 antigen which is associated with ganglion cells. The Thy-1 mRNA level was also reduced as was the mRNA for the common subunit of the NMDA receptor, the NR1 subunit. However, in animals subjected to a topical Betoptic(R)regime, before and after intravitreal injection of NMDA, the decreases in the mRNA levels of Thy-1 and NR1 were significantly attenuated.

Neuroprotection in relation to retinal ischemia and relevance to glaucoma

Management of glaucoma is directed at the control of intraocular pressure (IOP), yet it is recognized now that increased IOP isjust an important risk factor in glaucoma. Therapy that prevents the death of ganglion cells is the main goal of treatment, but an understanding of the causes of ganglion cell death and precisely how it occurs remains speculative. Present information supports the working hypothesis that ganglion cell death may result from a particular form of ischemia. Support for this view comes from the fact that not all types of retinal ischemia lead to the pathologic findings seen in glaucomatous retinas or to cupping in the optic disk area. Moreover, in animal experiments in which ischemia is caused by elevated IOP, a retinal abnormality similar to that seen in true glaucoma is produced, whereas after occlusion of the carotid arteries a different pattern of damage is found. In ischemia, glutamate is released, and this initiates the death of neurons that contain ionotropic glutamate (NMDA) receptors. Elevated glutamate levels exist in the vitreous humor of patients with glaucoma, and NMDA receptors exist on ganglion cells and a subset of amacrine cells. Experimental studies have shown that a variety of agents can be used to prevent the death of retinal neurons (particularly ganglion cells) induced by ischemia. These agents are generally those that block NMDA receptors to prevent the action of the released glutamate or substances that interfere with the subsequent cycle of events that lead to cell death. The major causes of cell death after activation of NMDA receptors are the influx of calcium into cells and the generation of free radicals. Substances that prevent this cascade of events are, therefore, often found to act as neuroprotective agents. For a substance to have a role as a neuroprotective agent in glaucoma, it would ideally be delivered topically to the eye and used repeatedly. It is, therefore, of interest that betaxolol, a beta-blocker presently used to reduce IOP in humans, also has calcium channel-blocking functions. Moreover, experimental studies show that betaxolol is an efficient neuro protective agent against retinal ischemia in animals, when injected directly into the eye or intraperitoneally.

Endothelin-induced changes in intracellular calcium in human microglia

Calcium-sensitive spectrofluorometry was used to study the effects of endothelin on levels of intracellular calcium [Ca2+]i in cultured human microglia. Both ET-1 and ET-3 induced transient, non-desensitizing, increases in [Ca2+]i in over 80% of the cells studied. The responses to either ET-1 or ET-3 were significantly diminished in amplitude and duration in Ca2+-free solution suggesting a prominent contribution of Ca2+ influx to the response. ET-1 induced changes in [Ca2+]i were not altered in the presence of the selective ET(A) antagonist BQ610 but were significantly reduced with the selective ET(B) antagonist BQ780. These results confirm the expression of ET(B) receptors on human microglia, these receptors may serve a role in a signaling pathway between microglia and endothelial cells.

Somatic mutations in the kinase domain of the Met/hepatocyte growth factor receptor gene in childhood hepatocellular carcinomas

The MET protooncogene encodes a transmembrane tyrosine kinase identified as the receptor of a polypeptide known as hepatocyte growth factor/scatter factor. We performed PCR-based single-strand conformational polymorphism and sequencing analysis of the tyrosine kinase domain of the MET gene (exon 15-19) in 75 primary liver cancers. Three missense mutations were detected exclusively in 10 childhood hepatocellular carcinomas (HCCs), while no mutations were detected in 16 adult HCCs, 21 cholangiocarcinomas, or 28 hepatoblastomas. The extremely short incubation period from hepatitis B virus infection to the genesis of childhood HCC as compared with the adult HCC suggests that there may be an additional mechanism that accelerates the carcinogenesis of childhood HCC. Our results indicate that mutations of the tyrosine kinase domain of the MET gene may be involved in the acceleration of the carcinogenesis in childhood HCC.

A case of aortocoronary dissection as a complication during a percutaneous transluminal coronary angioplasty (PTCA)

We report a case of aortocoronary dissection during a percutaneous transluminal coronary angioplasty (PTCA) which resulted from an antegrade and also a progressively retrograde extension of the coronary dissection into the Sinus of Valsalva and the ascending aorta. It was successfully treated with stenting without an operation, resulting in optimal coronary blood flow and diminution of the aortic dissection.

Brain-derived neurotrophic factor rapidly potentiates synaptic transmission through NMDA, but suppresses it through non-NMDA receptors in rat hippocampal neuron

Brain-derived neurotrophic factor (BDNF) rapidly enhances synaptic transmission among the hippocampal neurons. In order to examine which component of glutamate receptors participates in synaptic potentiation by BDNF, we have studied the effect of glutamate antagonists on excitatory postsynaptic currents (EPSCs) enhanced by BDNF, using cultured embryonic hippocampal neurons. In the presence of AP5, a N-methyl-D-aspartate (NMDA) antagonist, BDNF depressed the EPSCs. In contrast, BDNF enhanced the EPSCs in the presence of a non-NMDA antagonist CNQX. Our results suggest that BDNF acutely activates synaptic transmission via NMDA, but suppresses it via non-NMDA receptors in the hippocampus.

[A study on the effect that rehabilitation education influence on the knowledge attitude and practice of public health nurse]

The home visiting health nurses are important man-power who can serve various and persistent rehabilitation care to disabled person in community. The Community Based Rehabilitation project (CBR) of national rehabilitation center have been carried out from 1995. As a part of that project national health center performed rehabilitation education program for home visiting health nurses. The purpose of this study is to analysis the effect of this education. In the first stage all of those groups were educated for two weeks in national rehabilitation center. But only two group nurses, one is in a urban and the other in a rural community, have been educated continually in the field through discussing rehabilitation care case study. The data in this study were gathered from three group health nurses and analysed by SAS computer program. The results about knowledge, attitude and practice changes of the three group nurses were as follows. 1. In the pre education state the mean point of all nurses' attitude for rehabilitation was 59, but in the post education state that was 90. The difference between pre and post attitude is very significant (t = -14.1, p < 0.0001). 2. In the pre education state the mean point of all nurses' knowledge for rehabilitation was 45, but in the post education state that was 78. The difference between pre and post knowledge is very significant (t = -12.7, p < 0.0001). 3. In the pre education state the mean point of all nurses' practice for rehabilitation care was 37, but in the post education state that was 62. The difference between pre and post practice is very significant (t = -7.3, p < 0.0001). 4. In practice point, the two group nurses who have been educated continuously were superior to the other (t = -3.9, p < 0.001). 5. All points between the urban and rural nurses were no significant differences (p > 0.1). 6. All changes of the attitude, knowledge and practice did not affected by age (F = 0.58, p > 0.1), professional career (F = 0.61, p > 0.1), educational background (F = 0.97, p > 0.1).

Reduced dihydroxyacetone sensitivity and normal sensitivity to glyceraldehyde and oxidizing agent of ATP-sensitive K+ channels of pancreatic beta cells in NIDDM rats

The inhibition of ATP-sensitive K+(KATP) channels in pancreatic beta cells is a key step of insulin secretion induced by glucose. Glucose-induced insulin secretion from the beta cells is selectively impaired in patients with noninsulin-dependent diabetes mellitus (NIDDM) and in animal models of it. In order to clarify the site of this abnormal glucose response, we studied the effects of insulin secretagogues and sulfhydryl oxidizing agent, 2,2'-dithio-bis (5-nitropyridine) (DTBNP), on KATP channels in single beta cells of neonatally streptozotocin-induced NIDDM rats. We used the patch-clamp technique in cell-attached mode (Vpipette = 0 mV). The inhibitory response to glucose of KATP channels was lacking in NIDDM rats, indicating reduced sensitivity to glucose of the channels. Glyceraldehyde (2-5 mM) in the diabetic beta cells elicited the same KATP channel inhibition as that obtained in controls. In contrast, dihydroxyacetone (DHA, 2-10 mM) sensitivity of KATP channels was significantly reduced in the beta cells of NIDDM rats. KATP channels in the diabetic beta cells were rapidly inhibited by 50 microM DTBNP, just as in the normal beta cells, suggesting that KATP channel function was normal. This indicates that one of the sites responsible for impaired glucose-induced insulin secretion in the pancreatic beta cells of NIDDM rats is located in the glycerol phosphate shuttle.

A genetic study of dentin growth in the mandibular second and third molars of male mice

Although the influence of genetic and environmental factors on the completed crown size of mandibular molars in mice is well known, such influence on the growth process of the mandibular second and third molars of mice has not yet been clarified. The purpose of the present study is to examine the growth pattern of the dentinal formation and evaluate the relative contributions of both genetic and environmental factors to longitudinal dentin formation by the use of the partial diallel cross-genetic approach, the time-marking method and a computerized image measurement system. The following results were obtained: 1) the onset of dentinal formation in the second molar was on the 6-9th day after birth, while that of the third molar was on the 9-12th day after birth; 2) the best fitted growth curve of the dentinal formation for the first molar was the fifth order polynomial equation, while for the second molar the fourth order polynomial equation was best, and for the third molar the third order polynomial equation was best; 3) maternal effect strongly influenced the second and the third molar dentin growth at an early stage of postnatal growth. Thus, it could be concluded that the dentinal formation growth pattern differed among the three kinds of mouse molars while maternal environmental factors, in addition to genetic factors, played an important role in the mouse second and third molar dentin growth during the early stage of postnatal growth.

Biphasic modifying effect of indole-3-carbinol on diethylnitrosamine-induced preneoplastic glutathione S-transferase placental form-positive liver cell foci in Sprague-Dawley rats

The biphasic modifying effects of indole-3-carbinol (I3C), a naturally occurring constituent of edible cruciferous vegetables, on the development of glutathione S-transferase placental form (GST-P)-positive liver cell foci were investigated by using a medium-term liver bioassay system and a newborn rat hepatocarcinogenesis system. In Experiment 1, a total of 65 male Sprague-Dawley (SD) rats were divided into 5 groups. Animals were given a single intraperitoneal (i.p.) injection of 200 mg/kg diethylnitrosamine (DEN) dissolved in saline for groups 1, 2, and 3 or a single i.p. injection of saline for groups 4 and 5. Group 1 was given the diet containing 0.25% I3C for 2 weeks prior to DEN initiation and then basal diet for 8 weeks. Group 2 was given basal diet for 4 weeks prior to and after DEN initiation and then the diet containing 0.25% I3C for 6 weeks. The rats of group 3 were placed on basal diet during the experiment. Animals of groups 4 and 5 were treated in the same manner as those of groups 1 and 2 except for injection with saline instead of DEN solution. All rats were subjected to two-thirds partial hepatectomy at week 3 and were killed at week 8 after DEN or saline injection. In Experiment 2, a total of 45 female SD rats were dosed with DEN (100 mg/kg, i.p.) or saline at 24 h after birth. After weaning at week 3, the rats were fed diet containing 0.25% I3C for 9 weeks and then were killed at week 12. In Experiment 1, preinitiation exposure to 0.25% I3C caused a significant decrease in numbers of GST-P-positive liver cell foci (P < 0.05), while postinitiation exposure to 0.25% I3C caused significant increases in both number (No./cm2) and area (mm2/cm2) of GST-P-positive liver cell foci (P < 0.05 or 0.01). In Experiment 2, the relative liver weight in the DEN + I3C group was significantly increased (P < 0.001). The numbers and areas of GST-P-positive liver cell foci in the DEN + I3C group were significantly increased as compared to the values of the DEN-alone group (P < 0.001). These results clearly demonstrated that I3C exerts a promoting effect on the postinitiation stage as well as an inhibitory effect on the preinitiation stage in the medium-term liver bioassay.

Identification of a high-affinity glycine betaine transport system in Staphylococcus aureus

Staphylococcus aureus accumulates proline and glycine betaine when cells are grown at low water activity. In the present study, we have identified a high-affinity glycine betaine transport system in this bacterium. Optimal activity for this transport system was measured in the presence of high NaCl concentrations, but transport activity was not stimulated by high concentrations of other solutes.

Search for the heparin antithrombin III-binding site precursor

The last step of heparin biosynthesis is thought to involve the action of 3-O-sulfotransferase resulting in the formation of an antithrombin III (ATIII) binding site required for heparin's anticoagulant activity. The isolation of a significant fraction of heparin chains without antithrombin III-binding sites and having low affinity for ATIII suggests the presence of a precursor site, lacking the 3-O-sulfate group. Porcine mucosal heparin was depolymerized into a mixture of oligosaccharides using heparin lyase. One of these oligosaccharides was derived from heparin's ATIII-binding site. In an effort to find the ATIII-binding site precursor, the structures of several minor oligosaccharides were determined. A greater than 90% recovery of oligosaccharides (on a mole and weight basis) was obtained for both unfractionated and affinity-fractionated heparins. An oligosaccharide arising from the ATIII-binding site precursor was found that comprised only 0.8 mol % of the oligosaccharide product mixture. This oligosaccharide was only slightly enriched in heparin having a low affinity for ATIII and only slightly disenriched in high affinity heparin. The small number of these ATIII-binding site precursors, found in unfractionated and fractionated heparins, suggests the existence of a low ATIII affinity heparin may not simply be the result of the incomplete action of 3-O-sulfotransferase in the final step in heparin biosynthesis. Rather these data suggest that some earlier step, involved in the formation of placement of these precursor sites, may be primarily responsible for high and low ATIII affinity heparins.

Identification of two proline transport systems in Staphylococcus aureus and their possible roles in osmoregulation

The food-borne pathogen Staphylococcus aureus is distinguished from other food-borne pathogens by its ability to grow at water activity values below 0.90. Previous studies have indicated that proline accumulation mediated by transport represents a primary osmoregulatory strategy utilized by this bacterium (C. B. Anderson and L. D. Witter, Appl. Environ, Microbiol. 43:1501-1503, 1982; I. Koujima, H. Hayashi, K. Tomochika, A. Okabe, and Y. Kanemasa, Appl. Environ. Microbiol. 35:467-470, 1978; K. J. Miller, S. C. Zelt, and J.-H. Bae, Curr. Microbiol. 23:131-137, 1991). In this study, we demonstrate the presence of two proline transport systems within whole cells of S. aureus, a high-affinity transport system (Km, 7 microM) and a low-affinity transport system (Km, 420 microM). Our results indicate that the low-affinity proline transport system is osmotically activated and is the primary system responsible for the accumulation of proline by this pathogen during growth at low water activity.

Modifying responses of allyl sulfide, indole-3-carbinol and germanium in a rat multi-organ carcinogenesis model

The modifying potential of allyl sulfide (AS), indole-3-carbinol (I3C) and carboxyethylgermanium sesquioxide (GE) on lesion development was examined in a wide-spectrum initiation model. Groups 1-4 were treated sequentially with diethylnitrosamine (DEN) (100 mg/kg, i.p., single dose), N-methylnitrosourea (MNU) (20 mg/kg, i.p., four doses at days 2, 5, 8 and 11), and N,N-dibutylnitrosamine (DBN) (0.05% in drinking water during weeks 3 and 4). Groups 5-7 received vehicles without carcinogens during the initiation period. Group 8 served as the untreated control. After this initiating procedure, groups 2-7 were administered a diet containing 0.5% AS or I3C and 0.05% GE. All surviving animals were killed 40 weeks after the beginning of the experiment and the target organs were examined. The induction of GST-P+ hepatic foci in rats treated with carcinogens was significantly inhibited by treatment with all three compounds. AS treatment significantly decreased the incidence of hepatic hyperplastic nodules, adenoma of the lung and thyroid, and papillary or nodular hyperplasia of the urinary bladder. Administration of GE also significantly inhibited the development of hepatic nodules and adenoma of the lung and thyroid. However, I3C only inhibited the hyperplastic nodules of the liver. These results demonstrated that this multi-organ initiation model could be useful in confirming organ-specific modification potential and, in addition, the inhibitory effect of AS, I3C and GE on liver, lung, thyroid and urinary bladder carcinogenesis.

Different modifying responses of capsaicin in a wide-spectrum initiation model of F344 rat

The modifying potential of capsaicin (CAP) on lesion development was examined in a rat multiorgan carcinogenesis model. Groups 1 and 2 were treated sequentially with diethylnitrosamine (DEN) (100 mg/kg, ip, single dose at commencement), N-methylnitrosourea (MNU) (20 mg/kg, ip, 4 doses at days 2, 5, 8, and 11), and N,N-dibutylnitrosamine (DBN) (0.05% in drinking water during weeks 3 and 4). Group 3 received vehicles without carcinogens during the initiation period. Group 4 served as the untreated control. After this initiating procedure, Groups 2 and 3 were administered a diet containing 0.01% CAP. All surviving animals were killed 20 weeks after the beginning of the experiment and the target organs examined histopathologically. The induction of GST-P+ hepatic foci in rats treated with carcinogens was significantly inhibited by treatment with CAP. CAP treatment significantly decreased the incidence of adenoma of the lung but increased the incidence of papillary or nodular (PN) hyperplasia of the urinary bladder. The tumor incidence of other organs, such as the kidney and thyroid, was not significantly different from the corresponding controls. These results demonstrated that concurrent treatment with CAP not only can inhibit carcinogenesis but can also enhance it depending on the organ. Thus, this wide-spectrum initiation model could be used to confirm organ-specific modification potential and, in addition, demonstrate different modifying effects of CAP on liver, lung, and bladder carcinogenesis.

Doxorubicin cardiotoxicity: response of left ventricular ejection fraction to exercise and incidence of regional wall motion abnormalities

Gated radionuclide ventriculograms were performed to evaluate cardiac function in 53 patients who received doxorubicin treatment for various malignancies (mean dose: 449 +/- 128 mg/m2 BSA). In fourteen patients (Group I) function was evaluated before and after treatment; there was a significant decrease of resting left ventricular ejection fraction after therapy (p less than 0.001). Twenty-two patients (Group II) had serial studies during treatment which also showed a significant fall of resting left ventricular ejection fraction (p less than 0.001). Eighteen patients in Groups I and II had supine exercise studies. A normal exercise response was maintained in the majority of patients. Exercise testing added little to the diagnostic performance when compared to serial resting studies. We found regional wall motion abnormalities (mild apical hypokinesis) at rest by visual inspection in 33 of 36 Group I and Group II patients who had received doxorubicin. In the baseline or initial study, only 4 of these patients demonstrated WMA. In 18 Group I and II patients who were exercised, 3 had wall motion abnormalities during the initial study. All of these patients demonstrated wall motion abnormalities at rest after the second study, however only 7 of 18 demonstrated abnormalities during the exercise study. The results indicate that resting left ventricular ejection fraction declines after doxorubicin treatment. Exercise radionuclide angiography may not increase diagnostic accuracy for the detection of doxorubicin related cardiotoxicity. Regional wall motion abnormalities occur with a relatively high incidence following doxorubicin therapy, more readily detectable at rest. However, the exercise study can distinguish doxorubicin related wall motion abnormalities from those due to coronary artery disease.

The frequency distribution of cardiovascular diseases in 13 hospital admitted patients in Korea. Korean Society of Circulation

The frequency distribution of cardiovascular disease are changing recently due to the development of living environment. Unfortunately there are few epidemiological studies of cardiovascular diseases in general population, we tried to estimate the recent trend of cardiovascular diseases studying hospitalized patients in nationwide 13 large hospitals during a year of 1985. The hypertensive disease (24.1%) was the most common cardiovascular disease and the next were cerebrovascular disease (15.8%), arrhythmias (12.2%), ischemic heart disease (9.7%), congenital heart disease (9.1%), and rheumatic heart disease (5.4%) in order. This results showed that hypertensive disease and cerebrovascular disease are still the major cardiovascular disease and ischemic heart disease and arrhythmias are increased. But chronic rheumatic heart disease is declined compared with previous studies in hospitalized patients.

A study on cerebral embolism in mitral stenosis

To evaluate the significance of episodes of cerebral embolism in patients with mitral valve disease in Korea, 128 patients with echocardiographic diagnosis of mitral valve disease were examined. Among these, 82 patients had predominant mitral stenosis. 1. The clinical features of 82 patients with mitral stenosis have been reviewed to elucidate the factors favoring cerebral embolism which occurred in 19 patients, i.e., incidence of 23.2%. 2. Atrial fibrillation was present in 16 of 19 patients with cerebral embolism (84.2%). Cerebral embolic episodes occurred in 16 of 47 patients with atrial fibrillation (34.0%). 3. The mean age (55.3 ± 12.1 years) of patients without cerebral embolism was significantly older than that (43.2 ± 14.6 years) of patients without cerebral embolism (P<0.005). 4. There was no significant relationship between the incidence of embolism and sex, left atrial thrombi, left atrium/aortic root diameter, mitral valvular orifice area, mitral valvular vegetation or calcification, left ventricular enddiastolic dimension or left ventricular posterior wall thickness. Cerebral embolism is common in patients with mitral stenosis in our country. The presence of atrial fibrillation and low cardiac output increase the attack of cerebral emboli whereas the severity of mitral stenosis, as judged by valve area, may not correlate with the occurrence of emboli. The best treatment for cerebral embolism is prevention. Therefore, we believe that more vigorous treatment of patients with mitral valve disease who are old or associated with atrial fibrillation as well as previous embolic history is indicated.

In vitro study of the pressure-velocity relation across stenotic orifices

In a hand-driven, pulsatile in vitro model, the pressure-velocity relation across stenotic orifices was studied from simultaneous measurements recorded over a wide range of pressure and across different-sized orifices, individually and paired. Velocity spectra were recorded with continuous-wave Doppler ultrasound. In a rigid, noncompliant system, integrated instantaneous maximal velocities precisely register simultaneous integrated pressure gradients without measureable phase shift. Across stenotic orifices of 5 to 10 mm in diameter, the pressure-velocity relation is independent of orifice size for pressures extending from -30 to +240 mm Hg. The relation is quadratic and crosses 0. In this model, application of the simplified Bernoulli equation transforms the relation from curvilinear to linear with a bias toward the derived-pressure axis. In the presence of 2 different-sized orifices, the pressure-velocity relation remains constant, with a given pressure producing 2 identical velocities.

Left ventricular stroke volume determinations from radionuclide ventriculograms: the effects of photon attenuation

To improve the accuracy of scintigraphic ventricular volume determination, which is limited by photon attenuation between the heart and the gamma camera, a method was developed for directly measuring the photon attenuation of radioactivity delivered as a bolus through a Swan-Ganz catheter into the right atrium. Comparison of the count rate recovered from this bolus with the total ex vivo measured activity determined by imaging an aliquot of the administered activity allowed calculation of the attenuation factor. Left ventricular stroke volumes determined scintigraphically by the count method in gated blood pool studies and then corrected with this attenuation factor correlated well with stroke volumes determined from thermodilution cardiac output and heart rate (r = 0.92; SEE, 6.1 ml). The agreement between the two measurements was markedly less when an average attenuation factor was employed for correction of scintigraphic volumes (r = 0.52; SEE, 14.8 ml). The results indicate that correction for photon attenuation is needed for accurate measurement of left ventricular volumes. Correction of left ventricular counts based on body weight or body surface area improves the accuracy of volume estimates.