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Mechanosensitive cation channels may be involved in the development of the myogenic tone of arteries. The molecular identity of these channels is not clear, but transient receptor potential channels (TRPCs) are good candidates. In the present study, we searched for mechanosensitive channels at the single-channel level in arterial smooth muscle cells using the patch-clamp technique and investigated the channel properties in the light of properties of TRPCs. With 140 mmol/L CsCl in the pipette solution, application of negative pressures to the back of the pipette induced the activation of channels the open probability of which increased with the amount of negative pressure. The current-voltage relationship was linear in symmetrical ionic conditions, and the single-channel conductances for Cs+, K+, and Na+ were 30, 36, and 27 pS, respectively. When NMDG+ was substituted for Cs+ in the pipette solution, inward currents were abolished, whereas outward currents remained active, indicating that the channels were nonselective to cations. The channel activity was blocked by intracellular Gd3+ and 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid and increased by diacylglycerol and by cyclopiazonic acid. Phospholipase C inhibitor (U73122) inhibited not only channel activity but also the development of myogenic tone induced by stretching of the basilar arteries. These results suggest that the ion channel responsible for the development of myogenic tone is the 30-pS mechanosensitive cation channel that exhibits properties similar to those of TRPCs.

Using the inside-out patch-clamp technique, large-conductance Ca2+ -activated K+ channel (BK(Ca)) currents were recorded from coronary artery smooth muscle cells. Cytochalasin D, an actin filament disrupter, increased channel activity ( NP(o), where N is the number of channels and P(o) the open probability), and this increase was reversed by phalloidin, an actin filament stabilizer. NP(o) was also increased by colchicine, a microtubule disrupter, and decreased by taxol, a microtubule stabilizer. With the stepwise increase of negative pressure in the patch pipettes, the activity of BK(Ca) gradually increased: the maximum effect (527% increase in NP(o)) was achieved at -40 cmH(2)O and the half-maximum effect at -25 cmH(2)O. The increase in NP(o) in response to negative pressure was abolished by phalloidin but not by taxol. These results imply that both actin filaments and microtubules inhibit the opening of BK(Ca) in coronary artery smooth muscle cells, but that only actin filaments are involved in the stretch sensitivity of BK(Ca).

Background: Earlier reports of the advantages of preservating the posterior branches of the great auricular nerve (GAN) at parotidectomy were conflicting. This prospective study was aimed at clarifying the controversy., Methods: Eighty-one patients in a university otolaryngology department were recruited. The posterior branches were preserved whenever initial dissection showed that tumor clearance would not be compromised. Touch-pressure sensation was monitored in predefined territories supplied by the GAN using a Semmes-Weinstein aesthesiometer, preoperatively and postoperatively. Minimal pressure thresholds obtained were compared between the two groups., Results: Preservation of the GAN was achievable in 69% of patients; sensory deficit was transient. With the GAN divided, measurable sensory depression occurred up to 2 years after surgery. The difference is statistically significant. Patients' subjective assessment of numbness also conformed to these trends. Additional time taken for preservation of the GAN was about 10 minutes., Conclusions: The posterior branches should always be preserved if tumor clearance is not compromised.

Familiarity with four types of free tissues transfers allows appropriate reconstruction of most defects in the head and neck region functionally and aesthetically. These include jejunal graft, radial forearm, rectus abdominus myocutaneous and fibula osteocutaneous flaps. Free colonic and gastric patches were used occasionally. We report our experience of 215 free tissue transfers for reconstruction of defects in the head and neck region after tumour extirpation. The overall success rate was 94 per cent. The commonest cause of failure was related to arterial inflow (70 per cent). Three patients died in hospital, but their mortality was not related to the tissue transfers. Complications due to free tissue transfer at both the donor and recipient sites were few and manageable. The co-operation between the two surgical teams, together with the timely application of suitable salvage procedures, contribute to an optimal outcome.

Objective: Complications after ventilation tube insertion for middle ear effusion in patients with nasopharyngeal carcinoma are frequent. This may compromise the overall benefit obtained from the procedure. This study evaluates the hearing improvement after tube insertion compared with observation alone to see if the benefits of the procedure outweigh its potential complications., Design: Prospective randomized controlled trial., Setting: Full clinical and emergency otolaryngologic services hospital in an academic institution., Methods: Patients with nasopharyngeal carcinoma and middle ear effusion were randomized for preradiotherapy ventilation tube insertion or observation. Audiologic assessment with a pure-tone audiogram was performed before the procedure, after ventilation tube insertion, and at fixed intervals after irradiation. Audiologic outcome was compared between the two groups., Main Outcome Measure: Air-conduction threshold and air-bone gap on a pure-tone audiogram at different intervals after radiotherapy., Results: There was no significant difference in hearing threshold changes between the two groups for up to 4 years. Both groups had air-bone gap improvement following radiotherapy and the improvement was not significantly different between the two groups. The proportion of patients with closure of the air-bone gap on follow-up was not different between the two groups., Conclusions: Ventilation tube insertion before radiotherapy did not offer additional hearing benefit when compared with observation alone. The procedure had no deleterious effect on hearing for up to 4 years.

Aim: There is still controversy on the incidence of positive expression of bcl-2 and its prognostic significance for oral tongue carcinoma patients who are treated by surgery. The present study aims at resolving the controversy on the clinicopathologic significance of bcl-2 in a well selected group of patients who satisfy the recruitment criteria: (1) oral tongue carcinoma, (2) squamous cell carcinoma, (3) primary surgical treatment., Method: Bcl-2 expression was studied by immunohistochemistry on glossectomy specimens of 73 patients. The expression of bcl-2 was correlated with clinicopathologic data., Results: Of the 73 tumours, 11% had positive expression of bcl-2. Bcl-2 expression was not significantly correlated with tumour grade, stage, nodal metastasis and survival., Conclusion: Bcl-2 expression played a minor role in oral tongue carcinoma. It had no significant correlation with tumour grade, stage and nodal metastasis. It also had no prognostic value on survival for patients who were treated by primary surgery.

Two different families of Na+/Ca2+ exchangers, K+-independent NCX and K+-dependent NCKX, are known. Exploiting the outward K+ gradient, NCKX is able to extrude Ca2+ more efficiently than NCX, even when the Na+ gradient is reduced. The NCKX, which was originally thought to be limited to the retinal photoreceptor, was shown recently to be widely distributed in the brain. We investigated the contribution of Na+/Ca2+ exchange to Ca2+ clearance mechanisms in neurohypophysial (NHP) axon terminals, using patch-clamp and microfluorometry techniques. In the presence of internal K+, Ca2+ decay was significantly slowed by the removal of external Na+, indicative of the role of Na+/Ca2+ exchange. As internal [K+] was decreased, Ca2+ decay rate and its dependence on Na+ were greatly attenuated. In the absence of internal K+, Ca2+ decay rate was little affected by Na+ removal. Quantitative analysis using Ca2+ decay rate constant indicated that >60% of Ca2+ extrusion is mediated by Na+/Ca2+ exchange when peak [Ca2+] level is higher than 500 nm, and approximately 90% of Na+/Ca2+ exchange activity is K+ dependent. In situ hybridization confirmed the expression of NCKX2 transcripts in the supraoptic nucleus in which soma of NHP axon terminals are located. To our knowledge, this is the first report to show the significant role of K+-dependent Na+/Ca2+ exchange in neuronal cells other than photoreceptors. Considering that axon terminals are subject to an invasion by high-frequency Na+ spikes, which may lower Na+ gradients, the presence of NCKX may have a functional significance in intracellular Ca2+ regulation.

Depletion of phosphatidylinositol 4,5-bisphosphate (PIP(2)) induced by phenylephrine or endothelin causes the inhibition of acetylcholine-activated K(+) current (I(KACh)) in atrial myocytes. In the present study, we have investigated the hypothesis that muscarinic receptor induced PIP(2) depletion also causes inhibition of I(KACh), resulting in desensitization. We confirmed the expression of G(q)-coupled muscarinic receptors in mouse atrial myocytes using reverse transcriptase-polymerase chain reaction. The involvement of M(1) and M(3) receptors in desensitization is examined using specific antagonists, 4-DAMP and pirenzepine, but they significantly reduced peak I(KACh), implying nonspecific M(2) blockade. When ACh-induced phosphoinositide depletion was specifically inhibited using PLCbeta1 knock-out mice, the extent of desensitization during 4 min was 47.5 +/- 3.2%, which was not different from that in wild type (46.8 +/- 2.1%). Phenylephrine-induced phosphoinositide hydrolysis and phenylephrine-induced inhibition of I(KACh) were not affected by PLCbeta1 knock-out. To facilitate PIP(2) depletion, replenishment of PIP(2) was blocked by wortmannin. Wortmannin did not affect the desensitization and the recovery from desensitization. These results suggest that PIP(2) depletion by acetylcholine does not contribute to short-term desensitization of I(KACh). The differential regulation of I(KACh) by different phospholipase C-linked receptors may imply that receptor co-localization is required for PIP(2) to act as a signaling molecule.

Kimura's disease is a chronic inflammatory disorder of unknown etiology. A 62-year-old man presented with asymptomatic cervical lymphadenopathy associated with eosinophilia and increased serum immunoglobulin E. Excision biopsy showed Kimura's disease. Three years later another groin lymph node appeared and showed similar pathologic features. Polymerase chain reaction for Ig heavy chain and T-cell receptor (TCR) genes on DNA extracted from the cervical lymph node showed smear patterns. However, polymerase chain reaction for TCRdelta gene showed a clonal rearrangement. Sequencing showed a complete VDJ rearrangement (Vdelta1-N-Ddelta2-N-Jdelta), confirming the presence of a clonal T cell population. The same clonal TCRdelta rearrangement was amplified by polymerase chain reaction from the groin lymph node biopsied 3 years later. These results showed that the primary and recurrent lesions were biologically related. Furthermore, the presence of identical T cell clones in different sites and at different times suggested that a clonal T cell population might have contributed to the pathogenesis in this case of Kimura's disease.

Purpose: To evaluate the changes in olfactory function in patients with nasopharyngeal carcinoma who have received radiation to the head and neck., Materials and Methods: Olfactory function of consecutive patients with nasopharyngeal carcinoma was assessed prospectively before irradiation and serially up to 1 year after radiotherapy by the Sniffin' Sticks (Erlangen, Germany) olfactory function test and by a patient symptom visual analogue scale., Results: Fifty-eight patients were recruited before radiotherapy was commenced. Three patients could not give a reliable response to the Sniffin' Sticks test even in this first assessment, and 7 patients did not return for evaluation after irradiation. Forty-eight patients were available for follow-up assessment. Mean olfactory threshold scores by the Sniffin' Sticks test were found to deteriorate significantly at 12 months when compared with the scores before irradiation (8.3 at 12 months vs 11.5 before irradiation; P =.001). Scores for olfactory discrimination and for identification did not exhibit any significant changes when assessed at 12 months (P >.05 for both). Subjective patient assessment of olfactory function with the visual analogue scale at 12 months did not demonstrate any significant differences when compared with patients' assessment before irradiation (P =.90). An increase in discharge was the only nasal symptom that demonstrated a significant change at 12 months when compared with the assessment before irradiation (P < 001)., Conclusions: Deterioration in olfactory threshold scores was found at 12 months after irradiation and was not noticed by the patients., (Copyright 2002, Elsevier Science (USA). All rights reserved.))

We investigated the role of intracellular Mg(2+) ([Mg(2+)](i)) in the regulation of membrane potential ( V(m)) in rabbit coronary artery smooth muscle cells. V(m), membrane currents and intracellular Ca(2+) ([Ca(2+)](i)) were measured using standard patch-clamp and microfluorometry techniques. When [Ca(2+)](i) was increased by caffeine, V(m) depolarized at low [Mg(2+)](i) (0.1 mM), but hyperpolarized at high [Mg(2+)](i) (> or =1.2 mM). Effects of [Mg(2+)](i) on caffeine-induced currents were investigated. [Mg(2+)](i) selectively facilitated the activation of Ca(2+)-activated K(+) currents ( I(K,Ca)), while Ca(2+)-activated Cl(-) currents ( I(Cl,Ca)) were unaffected. Simultaneous recording of [Ca(2+)](i) and I(K,Ca) at different [Mg(2+)](i) showed that [Mg(2+)](i) increased the Ca(2+) sensitivity of I(K,Ca). [Ca(2+)](i) also inhibited voltage-dependent K(+) (K(V)) currents, although this effect was significant only at low [Mg(2+)](i). These results imply that the relative contributions of I(K,Ca), I(Cl,Ca) and K(V) currents to V(m) during an increase in [Ca(2+)](i) are affected by [Mg(2+)](i): at low [Mg(2+)](i), activation of I(Cl,Ca) and inhibition of K(V) currents depolarized V(m); at high [Mg(2+)](i) the activation of I(K,Ca) predominated, resulting in hyperpolarization of V(m). In conclusion, [Mg(2+)](i) hyperpolarizes V(m) by selective facilitation of I(K,Ca) and may thus possibly contributes to the relaxation of the coronary artery.

Atrial myocytes secrete atrial natriuretic peptide (ANP) in response to mechanical stretch and can serve as a challenging model for studying stretch-secretion coupling. We have developed a technique for monitoring ANP secretion from single atrial myocytes, using neutral red and a CCD video camera. Atrial-specific granules (ASGs) containing ANP were stained with neutral red. The cells were illuminated with monochromatic light (550 mm) and the grey value monitored within the region of interest (ROI) surrounding the region in which ASGs were densely located. Assuming that neutral red is evenly distributed in ASGs, the change in optical density (OD) was considered to represent the total amount of secretion. Under control, non-stimulated conditions, the OD decreased spontaneously (19.7+/-1.4%/10 min, n=14). Direct mechanical stretch (cell length increased by 20%) with two micropipettes or hypotonic swelling (200 mOsm) accelerated the decrease in OD significantly (48.7+/-7.4%/10 min; n=3, 47.2+/-2.4%/10 min; n=7, respectively). In conclusion, this method allows monitoring of ANP secretion with a relatively high time resolution while mechanical stress is applied. Furthermore, patch-clamp or intracellular perfusion techniques can be combined with the present technique for studying cellular mechanisms of stretch-secretion coupling.

The 42-kDa carboxyl-terminal processing fragment of Plasmodium falciparum merozoite surface protein 1 (MSP-1(42)) is an anti-erythrocytic stage malaria vaccine candidate. In this study, MSP-1(42) was expressed by using the Bombyx mori nuclear polyhedrosis virus-silkworm expression system, and the antigenicity and immmunogenicity of the recombinant protein, Bmp42, were evaluated. The average yield of Bmp42, as determined by a sandwich enzyme-linked immunosorbent assay (ELISA), was 379 microg/ml of infected silkworm hemolymph, which was >100-fold higher than the level attainable in cell culture medium. N-terminal amino acid sequencing revealed that Bmp42 was correctly processed in silkworm cells. Data from immunoblotting, as well as from the inhibition ELISA, suggested that the conformational B-cell epitopes of MSP-1(42) were recreated in Bmp42. Immunization of rabbits with Bmp42 in complete Freund's adjuvant generated high-titer antibody responses against the immunogen. Specificity analyses of the anti-Bmp42 antibodies using several recombinant MSP-1(19) proteins expressing variant and conserved B-cell epitopes suggested that the anti-Bmp42 antibodies recognized primarily conserved epitopes on MSP-1(19). Furthermore, the anti-Bmp42 antibodies were highly effective in inhibiting the in vitro growth of parasites carrying homologous or heterologous MSP-1(42). Our results demonstrated that the baculovirus-silkworm expression system could be employed to express biologically and immunologically active recombinant MSP-1(42) at elevated levels; thus, it is an attractive alternative for producing a protective MSP-1(42) vaccine for human use.

Background: To study the impact of adding induction chemotherapy to radiotherapy on the long-term control of regional metastasis and survival in patients with nasopharyngeal carcinoma (NPC)., Methods: Between February 1988 and August 1993, 240 NPC patients with Ho's T3 stage, N2-3 stage, or nodal size >/=3 cm were recruited onto two randomized trials comparing induction chemotherapy followed by radiotherapy (CT + RT) and radiotherapy alone (RT) using a similar treatment protocol. Of these, 210 patients (105 in each treatment arm) had cervical nodal metastasis and were included in the analysis. Patients in the CT + RT arm received two to three cycles of cisplatin, 60 mg/m(2) day 1, + epirubicin, 110 mg/m(2) day 1, followed by radiotherapy. Radiotherapy technique and dose were similar in both arms. The median follow-up time was 71 months (range, 5-152 months)., Results: The overall response rate of nodal disease to chemotherapy was 86%, and the complete response (CR) rate was 44%. At the end of radiotherapy, 92% of patients in the CT + RT arm and 86% in the RT arm achieved CR in the neck (p =.12). The 5-year nodal relapse-free survival rates in the CT + RT and RT arm were 83% and 75%, respectively (p =.13). Most neck failures (81%) occurred during the first 36 months of follow-up. Radical neck dissection successfully salvaged 41% of neck failures in the CT + RT arm and 46% in the RT arm. The 5-year distant metastases-free survival rates were 70% in the CT + RT arm and 68% in the RT arm (p =.56), and the corresponding 5-year disease-specific survival rates were 66% and 68%, respectively (p =.55). In subgroup analysis, no significant differences in regional control and survival could be found in patients with Ho's N2-3 stage, AJCC N2-3 stage, or nodal size >6 cm., Conclusions: Induction chemotherapy does not seem to improve the regional control and survival in NPC patients with regional metastasis compared with radiotherapy alone and is not recommended as a routine treatment outside the context of a clinical trial., (Copyright 2002 Wiley Periodicals, Inc.)

The present study examined the hypolipidemic activity of hawthorn fruit. New Zealand white rabbits were fed one of three diets, a reference diet with no cholesterol added (NC), a high cholesterol diet (1 g/100 g, HC) and a HC diet supplemented with 2 g/100 g hawthorn fruit powder (HC-H). After 12 wk, serum total cholesterol (TC) and triacylglycerols (TG) were 23.4 and 22.2% lower, respectively, in the hawthorn fruit group compared with the HC rabbits (P < 0.05). Hawthorn supplementation led to 50.6% less cholesterol accumulation in aorta (P < 0.05) and 23-95% greater excretion of neutral and acidic sterols (P < 0.05). Supplementation of hawthorn fruit did not affect the activities of hepatic 3-hydroxy-3-methyl glutaryl coenzyme A reductase (HMG-CoA-R) or cholesterol 7alpha-hydroxylase (CH) but it suppressed the activity of intestinal acyl CoA:cholesterol acyltransferase (ACAT, P < 0.05). The results suggest that the mechanism by which hawthorn fruit decreases serum cholesterol involves, at least in part, the inhibition of cholesterol absorption mediated by down-regulation of intestinal ACAT activity.

Objectives: To evaluate the efficacy of afterloading brachytherapy following radical neck dissection (RND) in the management of extensive cervical lymph node disease in nasopharyngeal carcinoma after radiotherapy; and to examine prospectively prognostic factors and the pathologic behavior of neck disease., Patients: Twenty-seven patients with nasopharyngeal carcinoma who had extensive cervical lymph node metastasis following external radiotherapy were treated with RND. Thirteen of them also underwent afterloading brachytherapy with iridium wire (Ir 192). The RND specimens of the 27 patients were also examined with step serial whole-specimen sectioning., Results: All patients survived and their wounds healed primarily. Pathologic examination revealed 183 tumor-bearing lymph nodes that contained tumors in the neck: level I, 4% (8/183); level II, 53% (96/183); level III, 34% (62/183); level IV, 5% (9/183); and level V, 4% (8/183). Extracapsular tumor extension was seen in 84% of patients. Multivariate analysis identified the number of tumor-bearing lymph nodes detected in the specimens to be the only significant factor that affected control of disease. Although the neck disease in the group of patients who had afterloading brachytherapy was more extensive, the 3-year actuarial tumor control for the groups with and without brachytherapy were 60% and 61%, respectively., Conclusions: Recurrent cervical lymph nodes after radiotherapy in nasopharyngeal carcinoma are extensive and RND is mandatory for a successful salvage. When the nodal metastasis infiltrate or adhere to surrounding tissue, afterloading brachytherapy with iridium wire can provide satisfactory local tumor control.

Background: A retrospective analysis of treatment outcomes in patients with nasopharyngeal carcinoma (NPC) was performed in which the newly revised 1997 American Joint Committee on Cancer (AJCC) stage classification was applied and compared with the 1988 AJCC and Ho stage classifications, with emphasis on the predictive value of different staging systems in determining failure patterns in NPC., Methods: Three hundred and twenty-four patients with newly diagnosed NPC treated between September 1989 and August 1991 and originally staged according to Ho stage classification were re-staged according to the 1988 and 1997 AJCC stage classifications. In addition to stage grouping, patients were also classified into the following prognostic categories to study the failure patterns: early disease group (T1-2N0-1), advanced local disease group (T3-4N0-1), advanced nodal disease group (T1-2N2-3), and advanced locoregional disease group (T3-4N2-3). The overall survival (OAS), relapse-free survival (RFS), local relapse-free survival, nodal relapse-free survival, and distant metastases-free survival were compared among different stage groups and prognostic categories in the three staging systems., Results: In the new AJCC system, the percentages of patients with Stage I, II, III, and IV disease were 15.1%, 31.5%, 28.1%, and 25.3%, respectively, whereas most patients were classified as having Stage IV disease (65.7%) in the old AJCC system and Stage II or III disease (74.1%) in the Ho system. The 5 year OAS rates in the 1997 AJCC Stage I, II, III, and IV disease were 97.7%, 78.7%, 79.5%, and 61.4%, respectively. The corresponding 5 year RFS rates were 95.7%, 64.7%, 54.5%, and 41.1%. Using the 1997 AJCC system to define the four prognostic categories, the early disease group had the lowest incidence of relapse (27.6%) and death (18.4%), whereas the advanced locoregional disease group had the highest incidence of relapse (61.4%) and death (43.2%). Both the advanced local disease group and the advanced nodal disease group had similar rates of relapse (46.7% vs. 47.2%), but local relapse was the major cause of failure in the former group (61.8%), whereas distant metastases was the major cause in the latter group (44%)., Conclusions: Using the 1997 AJCC staging system, the authors observed a better distribution of patient numbers as well as segregation of survival curves among different stage groups. Moreover, prognostic categories with distinct prognosis and failure patterns were definable by the new system, which has important implications in selecting appropriate patient treatment strategies., (Copyright 2001 American Cancer Society.)

Aims: A prospective randomized study was conducted to evaluate the benefit of adjuvant levamisole/UFT (futraful and uracil) chemotherapy in head and neck squamous cell carcinoma., Methods: Sixty-five patients with stage III and IV squamous cell carcinomas of oral cavity, oropharynx, hypopharynx and larynx with no distant metastasis were randomized for the chemotherapy study. Thirty-one patients were randomized for chemotherapy and two of them were subsequently excluded. In this study, a total of 29 patients on levamisole/UFT therapy and 34 patients on the control group were analysed. The main outcome was measured by the 5-year disease-free actuarial survival rate., Results: The rates of distant metastasis were 10% for chemotherapy group and 32% for control group (P=0.06). The 5-year disease-free actuarial survival rates for patients with and without adjuvant chemotherapy were 57% and 39% respectively (P=0.207)., Conclusions: A trend of better distant control in head and neck cancer patients with post-operative adjuvant oral chemotherapy was observed. The side effects were minimal. However, there was no statistically significant improvement in the overall long-term survival. It may be of value to conduct a large-scale multi-centre prospective randomized study to verify the efficacy of levamisole and UFT as post-operative adjuvant chemotherapy for the control of distant metastasis in high-risk population., (Copyright Harcourt Publishers Limited.)

1. We have investigated the effect of U73122, a specific inhibitor of phospholipase C (PLC), on acetylcholine-activated K(+) currents (I(KACh)) in mouse atrial myocytes. 2. In perforated patch clamp mode, I(KACh) was activated by 10 microM acetylcholine. When atrial myocytes were pretreated with U73122 or U73343, I(KACh) was inhibited dose-dependently (half-maximal inhibition at 0.12+/-0.0085 and 0.16+/-0.0176 microM, respectively). The current-voltage relationships for I(KACh) in the absence and in the presence of U73122 showed that the inhibition occurred uniformly from -120 to +40 mV, indicating a voltage-independent inhibition. 3. When U73122 was applied after I(KACh) reached steady-state, a gradual decrease in I(KACh) was observed. The time course of the current decrease was well fitted to a single exponential, and the rate constant was proportional to the concentration of U73122. 4. When K(ACh) channels were directly activated by adding 1 mM GTP gamma S to the bath solution in inside-out patches, U73122 (1 microM) decreased the open probability significantly without change in mean open time. When K(ACh) channels were activated independently of G-protein activation by 20 mM Na(+), open probability was also inhibited by U73122. 5. Voltage-activated K(+) currents and inward rectifying K(+) currents were not affected by U73122. 6. These findings show that inhibition by U73122 and U73343 of K(ACh) channels occurs at a level downstream of the action of G beta gamma or Na(+) on channel activation. The interference with phosphatidylinositol 4,5-bisphosphate (PIP(2))-channel interaction can be suggested as a most plausible mechanism.

The membrane potential in vascular smooth muscle cells contributes to the regulation of cytosolic [Ca2+], which in turn regulates membrane potential by means of Ca2+i-dependent ionic currents. We investigated the characteristics of Ca2+i-dependent currents in rabbit coronary and pulmonary arterial smooth muscle cells. Ca2+i-dependent currents were recorded using the whole-cell patch-clamp technique while cytosolic [Ca2+] was increased by caffeine. The reversal potentials of caffeine-induced currents were between -80 and -10 mV under normal ionic conditions, whereas they were about 0 mV when K+-free NaCl solutions were used both in pipette and bath. The total substitution of extracellular Na+ with membrane-impermeable cation N-Methyl-D-glucamine did not affect caffeine-induced currents, implying no significant contribution of Na+ as a permeant ion to the currents. The substitution of extracellular NaCl with sucrose reduced outward component of the currents and shifted the reversal potentials according to the change in Cl- equilibrium potential. Upon application of the niflumic acid under K+-free conditions, most of the current induced by caffeine was inhibited. Taken together, the results of the present study indicate that K+ and Cl- currents are major components of Ca2+i-dependent currents in vascular smooth muscles isolated from coronary and pulmonary arteries of the rabbit, and the relative contribution of each type of current to total currents are not different between the two arteries.

A simple HPLC method with photodiode-array (PDA) ultraviolet detection was developed for the simultaneous determination of four active polyphenol components of hawthorn (Crataegus), chlorogenic acid, epicatechin, hyperoside and isoquercitrin, in rat plasma. Following extraction from the plasma samples with ethyl acetate-methanol (2:1, v/v), these four compounds were successfully separated using a C18 column with a gradient elution of 5 and 25% acetonitrile in 25 mM phosphate buffer (pH 2.4). The flow-rate was set at 1 ml/min and the eluent was detected at 325 nm for chlorogenic acid, 278 nm for epicatechin, and 360 nm for both hyperoside and isoquercitrin. Narignin (0.82 microg) was used as the internal standard and was detected at 278 nm. The method is linear over the studied range of 0.16-40, 0.63-160, 0.13-32 and 0.13-30 microg/ml for chlorogenic acid, epicatechin, hyperoside and isoquercitrin, respectively. The correlation coefficient for each analyte was greater than 0.995. The intra-day and inter-day precision of the analysis was better than 4 and 7%, respectively. The extraction recoveries at low to high concentration were greater than 85% for both epicatechin and chlorogenic acid, and greater than 94% for both hyperoside and isoquercitrin. The detection limits were 0.04, 0.20, 0.03 and 0.03 microg/ml for chlorogenic acid, epicatechin, hyperoside and isoquercitrin. The developed method was used to analyze the plasma concentrations of the four analytes after the intravenous administration of hawthorn polyphenol extract to rats.

The aim of the present study was to evaluate the clinicopathologic significance of p53 and p21 expression in lingual squamous cell carcinomas. Immunohistochemical staining was performed with p53 and p21 monoclonal antibodies on surgical specimens from 87 patients who underwent primary surgical treatment for lingual carcinoma between 1976 and 1996. We found positive expression of p53 in 45 (52%) of 87 cases and of p21 in 49 (56%) of 87 cases. There was no correlation of p53 and p21 expression with cancer stage, T stage, nodal metastasis, and tumor grade. Univariate analysis revealed that p21 expression, tumor stage, T stage, and nodal stage were significant prognostic factors for survival. However, only p21 expression and tumor stage were significant independent prognostic factors for survival in a multivariate Cox regression analysis. Overexpression of p21 but not p53 has prognostic value for survival in the surgical treatment of lingual carcinomas. The combination of stage with p21 expression is recommended for evaluation of prognosis and for management planning.

The effects of the protein kinase C inhibitors chelerythrine and bisindolylmaleimide I on acetylcholine-activated K+ currents (I(KACh)) were examined in atrial myocytes of mice, using the patch clamp technique. Chelerythrine and bisindolylmaleimide I inhibited I(KACh) in a reversible and dose-dependent manner. Half-maximal effective concentrations were 0.49+/-0.01 microM for chelerythrine and 98.69+/-12.68 nM for bisindolylmaleimide I. However, I(KACh) was not affected either by calphostin C, which is also known as a protein kinase C inhibitor, or by a protein kinase C activator, phorbol 12,13-dibutyrate. When K(ACh) channels were activated directly by adding 1 mM GTPgammaS to the bath solution in inside-out patches, chelerythrine (10 microM) decreased the open probability from 0.043+/-0.01 to 0.014+/-0.007 (n=5), but bisindolylmaleimide I did not affect the channel activity. From these results, it is concluded that both chelerythrine and bisindolylmaleimide I inhibit K(ACh) channels independently of protein kinase C inhibition, but the level of inhibition is different.

This investigation used a patch clamp technique to test the hypothesis that protein kinase G (PKG) contributes to the phosphorylation and activation of ATP-sensitive K(+) (K(ATP)) channels in rabbit ventricular myocytes. Nitric oxide donors and PKG activators facilitated pinacidil-induced K(ATP) channel activities in a concentration-dependent manner, and a selective PKG inhibitor abrogated these effects. In contrast, neither a selective protein kinase A (PKA) activator nor inhibitor had any effect on K(ATP) channels at concentrations up to 100 and 10 microm, respectively. Exogenous PKG, in the presence of both cGMP and ATP, increased channel activity, while the catalytic subunit of PKA had no effect. PKG activity was prevented by heat inactivation, replacing ATP with adenosine 5'-O-(thiotriphosphate) (a nonhydrolyzable analog of ATP), removing Mg(2+) from the internal solution, applying a PKG inhibitor, or by adding exogenous protein phosphatase 2A. The effects of cGMP analogs and PKG were observed under conditions in which PKA was repressed by a selective PKA inhibitor. The results suggest that K(ATP) channels are regulated by a PKG-signaling pathway that acts via PKG-dependent phosphorylation. This mechanism may, at least in part, contribute to a signaling pathway that induces ischemic preconditioning in rabbit ventricular myocytes.

Aims: Hyaline-vascular Castleman's disease (HVCD) and follicular dendritic cell (FDC) sarcoma occurring in the nasopharynx are both extremely rare. We report the first case of transformation of the former into the latter as documented by sequential biopsies. The steps involved in the transformation were described in detail and the possible role of p53 studied., Methods and Results: The patient presented at the age of 23 years with nasopharyngeal HVCD. Hyaline- vascular Castleman's disease with FDC overgrowth was diagnosed in a recurrence 8 years later, and a frank FDC sarcoma developed at the same site 11 years after initial presentation. The patient remained disease-free 3 years after excision and adjuvant chemotherapy. The FDC sarcoma comprised swirling fascicles of spindly cells with indistinct cell borders. The tumour cells expressed the FDC markers CD21, CD35 and CNA.42 and in-situ hybridization for Epstein-Barr virus-encoded RNAs was negative. Over-expression of p53 protein was observed in the FDC sarcoma and an increased number of weakly p53-positive spindly cells could also be demonstrated in the HVCD specimen. This finding suggested a possible role of p53 in the evolution from HVCD to FDC sarcoma. Critical analysis of the literature shows that, among the 13 reported cases of FDC sarcoma associated with Castleman's disease, possible progression from the latter to the former is documented in only two cases., Conclusions: The sequential changes observed in the current case provide further evidence to strengthen the role of HVCD as a possible precursor of FDC sarcoma. There is a possible role of p53 in the transformation process but confirmation by future studies is needed.

Bcl-2 expression was studied by immunohistochemistry on laryngectomy specimens from 176 patients. Of the 176 tumours, 11% had positive bcl-2 staining. Bcl-2 expression was significantly correlated with tumour grade: 5% of well-differentiated tumours, 12% of moderately-differentiated tumours and 23% of poorly-differentiated tumours had positive expression of bcl-2. Nodal metastases were also found to be significantly related to bcl-2 expression: 36% of nodal metastases for negative bcl-2 expression compared with 70% for positive expression. The risk of nodal metastases increased significantly with the presence of bcl-2 expression, moderate or poor differentiation and supraglottic involvement. The risk of nodal metastases increased significantly with the presence of increasing numbers of risk factors: 11% without risk factor, 21% with one risk factor, 49% with two risk factors and 77% with three risk factors. Bcl-2 expression in laryngeal carcinoma is significantly correlated with tumour grade and nodal metastases. It has added prognostic value for nodal metastases together with tumour grade and site of tumour involvement.

Objectives: This study aims at investigating the prognostic values of serum p53 protein and anti-p53 antibody in patients undergoing surgical treatment for head and neck squamous cell carcinoma (HNSCC)., Methods: Serum p53 protein and anti-p53 antibody concentrations were determined by an enzyme-linked immunosorbent assay (ELISA) in 75 patients with HNSCC and 28 healthy controls. In 28 patients, formalin-fixed tumor tissues were also available for immunohistochemical staining by an anti-p53 DO7 monoclonal antibody. The results were correlated with the clinicopathologic parameters., Results: The mean preoperative serum concentration of p53 protein in patients with HNSCC was significantly higher than healthy controls (59.45 pg/mL vs 16.4 pg/mL, p =.007). Preoperative serum p53 antibody was present in 23 (31%) patients and was present in one healthy control. Eighteen (62%) tumor tissues showed p53 overexpression by immunohistochemistry. The presence of serum anti-p53 antibody before operation was associated with a significantly higher incidence (65%) of nodal metastasis compared with 27% nodal metastasis in patients with absence of serum anti-p53 antibody (p =.002)., Conclusion: Preoperative serum p53 antibody was a significant prognostic factor for nodal metastasis of HNSCC.

Hawthorn fruit extract has been shown to have many health benefits including being cardiovascular protective, hypotensive and hypocholesterolemic. The present study was carried out to characterize further the antioxidants of hawthorn fruit and their effect on the oxidation of human low density lipoprotein (LDL) and alpha-tocopherol. The dry hawthorn fruit was extracted successively with ether, ethyl acetate, butanol and water. The ethyl acetate fraction was only effective in inhibition of Cu(+2)-mediated LDL oxidation. The column chromatographic separation led to isolation of eight pure compounds; namely, ursolic acid, hyperoside, isoquercitrin, epicatechin, chlorogenic acid, quercetin, rutin and protocatechuic acid. All of these phenolic compounds, except ursolic acid, were protective to human LDL from Cu(+2)-mediated LDL oxidation. They were also effective in preventing the peroxy free radical-induced oxidation of alpha-tocopherol in human LDL. The inhibitory effect of these compounds on oxidation of LDL and alpha-tocopherol was dose-dependent at concentrations ranging from 5 to 40 µM. In addition, supplementation of 2% hawthorn fruit powder significantly elevated serum alpha-tocopherol by 18-20% in rats fed a 30% polyunsaturated canola oil diet, as compared with the control. The present results suggest that part of the mechanism for cardiovascular protective effects of hawthorn fruit might also involve the direct protection to human LDL from oxidation or indirect protection via maintaining the concentration of alpha-tocopherol in human LDL.

Objectives: To study the relationship between the size of neopharynx after total laryngectomy and long-term swallowing function by means of scintigraphy., Study Design: The width of pharyngeal remnant was measured during surgery in 11 patients. Their swallowing function was assessed by scintigraphy 8 to 10 years after surgery., Methods: The width of pharyngeal remnant at its narrowest point in both relaxed and stretched state was measured during surgery. Postoperative scintigraphy data on swallowing were obtained and computed along 3 lines, (1) transit time through neopharynx, (2) percentage of bolus transferred, and (3) swallowing efficiency. The relationship between the 2 sets of data was analyzed by linear regression analysis., Results: (1) No statistically significant relationship was found between the size of neopharynx and swallowing function. (2) All patients are clinically asymptomatic., Conclusions: The swallowing function is not affected by the size of the neopharynx in 11 patients with pharyngeal remnant width ranging from 3 to 8 cm (stretched).

We have investigated the effect of alpha(1)-adrenergic agonist phenylephrine (PE) on acetylcholine-activated K(+) currents (I(KACh)). I(KACh) was recorded in mouse atrial myocytes using the patch clamp technique. I(KACh) was activated by 10 microm ACh and the current decreased by 44.27 +/- 2.38% (n = 12) during 4 min due to ACh-induced desensitization. When PE was applied with ACh, the extent of desensitization was markedly increased to 69.34 +/- 2.22% (n = 9), indicating the presence of PE-induced desensitization. I(KACh) was fully recovered from desensitization after a 6-min washout. PE-induced desensitization of I(KACh) was not affected by protein kinase C inhibitor, calphostin C, but abolished by phospholipase C (PLC) inhibitor, neomycin. When phophatidylinositol 4,5-bisphosphate (PIP(2)) replenishment was blocked by wortmannin (an inhibitor of phophatidylinositol 3-kinase and phophatidylinositol 4-kinase), desensitization of I(KACh) in the presence of PE was further increased (97.25 +/- 7.63%, n = 6). Furthermore, the recovery from PE-induced desensitization was inhibited, and the amplitude of I(KACh) at the second exposure after washout was reduced to 19.65 +/- 2.61% (n = 6) of the preceding level. These data suggest that the K(ACh) channel is modulated by PE through PLC stimulation and depletion of PIP(2).

Purpose: E-cadherin and catenins are important epithelial adhesion molecules in normal epithelium. Loss of E-cadherin-catenin adhesion is an important step in the progression of many epithelial cancers. E-cadherin and catenins expression in carcinoma of the tongue were evaluated in relation to their clinicopathological features and prognostic values., Method: Immunohistochemical staining was carried out with E-cadherin and (alpha, beta, gamma)-catenin monoclonal antibodies for 85 surgical specimens of oral tongue carcinoma, nine matched metastatic lymph nodes, and seven locally recurrent tumours., Results: There was under-expression in 85% of E-cadherin, 94% of alpha-catenin, 89% of beta-catenin, and 83% of gamma-catenin in the primary tumours. There was no correlation of E-cadherin/catenin expression with sex, age, cancer stage, and differentiation. Nodal metastasis was found in 68% of patients with weak expression of gamma-catenin compared with 9% with strong expression in primary tumours (chi-square, P = 0.02). E-cadherin was a significant prognostic factor for survival and recurrence; patients with weak E-cadherin expression had 53% 5-year survival compared with 85% with strong expression (Wilcoxon, P = 0.0159)., Conclusions: Both E-cadherin and catenins were highly under-expressed in oral tongue carcinoma, metastatic lymph node, and recurrent tumour. gamma-catenin had predictive value for nodal metastasis. E-cadherin was, however, a more important prognostic factor for recurrence and survival.

Objective: This study aimed to evaluate the effect of the external nasal dilator on the dimension of the nasal valve in Orientals., Design: A cohort study of normal subjects., Setting: Academic institution., Methods: The nasal fossae of normal subjects were assessed by acoustic rhinometry before and after application of the external nasal dilator., Main Outcome Measures: The minimal cross-sectional area of the nasal fossae and the total cross-sectional area of the nose., Results: Nasal fossae of 25 normal subjects were evaluated. There was a significant increase of 0.10 cm2 (SD = 0.16) or a 17% increase in the minimal cross-sectional area of the 50 nasal cavities after application of the external nasal dilator (Wilcoxon's matched-pairs signed rank test, p = .0001). A significant increase in the total minimal cross-sectional area for the whole nose after application was also present (0.19 cm2, SD = .27, or 16%; Wilcoxon's matched-pairs signed rank test, p = .0032)., Conclusions: The external nasal dilator results in an increase in the minimal cross-sectional area of the nasal airway in Orientals.

Background: This study aimed at resolving the clinicopathological significance of p53 and p21 expression in patients undergoing surgical treatment for laryngeal carcinoma., Materials and Methods: p53 and p21 expression were studied by immunohistochemical method on surgical specimens of 193 patients. The expressions of p53 and p21 were correlated with the clinicopathological data., Results: Of the 193 tumors, 60% had positive p53 expression and 46% had positive p21 expression. Nodal metastasis was significantly correlated with p53 overexpression, supraglottic involvement and moderate- to poor-differentiation of the tumor. There was significant cumulative effect with increasing risk of nodal metastasis with increasing number of risk factors: 0% without any risk factor, 13% with 1 risk factor, 37% with 2 risk factors and 55% with all 3 risk factors., Conclusion: Positive expressions p53 and p21 were common in laryngeal carcinoma. Overexpression of p53 but not p21 was associated with nodal metastasis. The use of p53 expression has added value in providing more accurate prognostic analysis of risk of nodal metastasis in conjunction with site of tumor involvement and tumor grade.

Aim: The present study was aimed to examine the vasorelaxant and antiproliferative responses to purified green tea epicatechin mixture, (-)epicatechin and (-)epigallocatechin gallate on rat arterial smooth muscle cells., Methods: Changes in isometric force were measured by Grass force transducer and effects on cell proliferation were evaluated using [3H]thymidine incorporation assay., Results: Epicatechin mixture, (-)epicatechin and (-)epigallocatechin gallate, which we isolated and purified from jasmine green tea, concentration-dependently, reduced the contractile response to phenylephrine in rat isolated aortic rings with (-)epigallocatechin gallate being more effective. These three agents also inhibited [3H]thymidine incorporation into DNA in cultured rat aortic smooth muscle cells in a concentration-dependent manner., Conclusion: The purified epicatechin derivatives from jasmine green tea relaxed the isolated rat arteries preconstricted by phenylephrine and inhibited aortic smooth muscle cell proliferation.

The aim of this study was to evaluate the correlation between pure tone audiogram results and the subjective sensation of hearing benefit of patients who had tympanoplasty for chronic suppurative otitis media. This is a prospective study of 115 patients who had tympanoplasty between 1992 and 1994. The outcome, including a pure tone audiogram and the subjective sensation of hearing benefit, was evaluated at 1 year after operation. There were 63 (55%) patients with subjective hearing benefit after the tympanoplasty. The subjective sensation of hearing benefit correlated with the magnitude of the air conduction (AC) threshold reduction, and increased from 39% for an AC reduction of less than or equal to 10 dB to 100% for an AC reduction of more than 30 dB. The effect of the interaural AC threshold difference on the subjective sensation of hearing was not significant; improvement was felt by 92% of patients when the operated ear became the better hearing ear, and by 73% of patients when the operated ear remained the worse hearing ear. There was considerable discrepancy between the subjective hearing benefit and the pure tone audiogram results. A combination of parameters, including the air-bone gap, the AC threshold, and the subjective hearing change, is recommended in reporting the results of tympanoplasty.

1. Amitriptyline has been known to induce QT prolongation and torsades de pointes which causes sudden death. We studied the effects of amitriptyline on the human ether-a-go-go-related gene (HERG) channel expressed in Xenopus oocytes and on the rapidly activating delayed rectifier K(+) current (I(Kr)) in rat atrial myocytes. 2. The amplitudes of steady-state currents and tail currents of HERG were decreased by amitriptyline dose-dependently. The decrease became more pronounced at more positive potential, suggesting that the block of HERG by amitriptyline is voltage dependent. IC(50) for amitriptyline block of HERG current was progressively decreased according to depolarization: IC(50) values at -30, -10, +10 and +30 mV were 23.0, 8.71, 5.96 and 4.66 microM, respectively. 3. Block of HERG by amitriptyline was use dependent: exhibiting a much faster block at higher activation frequency. Subsequent decrease in frequency after high activation frequency resulted in a partial relief of HERG blockade. 4. Steady-state block by amitriptyline was obtained while depolarization to +20 mV for 0.5 s was applied at 0.5 Hz: IC(50) was 3.26 microM in 2 mM [K(+)](o). It was increased to 4. 78 microM in 4 mM [K(+)](o), suggesting that the affinity of amitriptyline on HERG was decreased by external K(+). 5. In rat atrial myocytes bathed in 35 degrees C, 5 microM amitriptyline blocked I(Kr) by 55%. However, transient outward K(+) current (I(to)) was not significantly affected. 6. In summary, the data suggest that the block of HERG currents may contribute to arrhythmogenic side effects of amitriptyline.

1. Stretch-activated channels (SACs) were studied in isolated rat atrial myocytes using the whole-cell and single-channel patch clamp techniques. Longitudinal stretch was applied by using two patch electrodes. 2. In current clamp configuration, mechanical stretch of 20 % of resting cell length depolarised the resting membrane potential (RMP) from -63.6 +/- 0.58 mV (n = 19) to -54.6 +/- 2.4 mV (n = 13) and prolonged the action potential duration (APD) by 32.2 +/- 8.8 ms (n = 7). Depolarisation, if strong enough, triggered spontaneous APs. In the voltage clamp configuration, stretch increased membrane conductance in a progressive manner. The current-voltage (I-V ) relationship of the stretch-activated current (ISAC) was linear and reversed at -6.1 +/- 3.7 mV (n = 7). 3. The inward component of ISAC was abolished by the replacement of Na+ with NMDG+, but ISAC was hardly altered by the Cl- channel blocker DIDS or removal of external Cl-. The permeability ratio for various cations (PCs:PNa:PLi = 1.05:1:0.98) indicated that the SAC current was a non-selective cation current (ISAC,NC). The background current was also found to be non-selective to cations (INSC,b); the permeability ratio (PCs:PNa:PLi = 1.49:1:0.70) was different from that of ISAC,NC. 4. Gadolinium (Gd3+) acted on INSC,b and ISAC,NC differently. Gd3+ inhibited INSC,b in a concentration-dependent manner with an IC50 value of 46.2 +/- 0.8 microM (n = 5). Consistent with this effect, Gd3+ hyperpolarised the resting membrane potential (-71.1 +/- 0.26 mV, n = 9). In the presence of Gd3+ (0.1 mM), stretch still induced ISAC,NC and diastolic depolarisation. 5. Single-channel activities were recorded in isotonic Na+ and Cs+ solutions using the inside-out configuration. In NMDG+ solution, outward currents were abolished. Gd3+ (100 microM) strongly inhibited channel opening both from the inside and outside. In the presence of Gd3+ (100 microM) in the pipette solution, an increase in pipette pressure induced an increase in channel opening (21.27 +/- 0.24 pS; n = 7), which was distinct from background activity. 6. We concluded from the above results that longitudinal stret in rat atrial myocytes induces the activation of non-selective cation channels that can be distinguished from background channels by their different electrophysiology and pharmacology.

Cantonese language rehabilitation in 28 prelingually deaf children who underwent cochlear implantation was evaluated. All patients were implanted with multichannel devices and the operations went smoothly. They all had improved scores on audiological assessments and speech perception tests. The speech evaluation tests included the recognition of sounds, vowels, consonants and tone. Sentence recognition and story comprehension were both improved after training for 2 years. Cochlear implantation is a useful measure for the speech rehabilitation of prelingually profound deaf children when hearing aids are of no benefit. The multichannel implant device is of clinical significance in the rehabilitation of those patients using tonal language.

We investigated the permeability of Cs+ and Na+ through various ion channels in rat atrial myocytes using the whole-cell voltage-clamp technique. With isotonic CsCl (140 mM) on both sides of the membrane and nominally [Ca2+]o-free conditions, depolarising clamp pulses induced an increase of outward currents which showed a biphasic time course. Repolarisation to the holding potential induced inward tail currents. With isotonic NaCl, depolarisation also induced outward currents which showed a monotonic decay, but inward tail currents were not observed. Both in NaCl and CsCl, currents were hardly affected by TEA (10 mM), 4-AP (5 mM) and DIDS (100 microM). Nicardipine (1 M) almost completely blocked time-dependent outward currents in isotonic NaCl solution, leaving only time-independent currents which showed linear I-V relationship. In isotonic CsCl conditions, nicardipine blocked outward current considerably, but there still remained time-dependent outward currents and inward tail currents. Addition of E-4031 (2-20 M) which is known as a specific blocker of the rapidly activating delayed rectifier K+ current (IKr) completely blocked these time-dependent outward and inward currents, leaving only a time-independent current. Time-independent currents recorded in the presence of nicardipine and E-4031 were inhibited by GdCl3, which is known to block non-selective cation (NSC) currents. From these results, it was suggested that NSC current in atrial myocytes can be investigated in isotonic Cs+ or Na+ solution in the presence of Ca2+ channel and IKr blockers.

Asian nations differ from one another in population, cultural background, ethnic tradition and economic situation. The training of otorhinolaryngologists in Asia is not in any way uniform. A questionnaire survey of 26 leading institutions in 12 countries/regions was carried out. The emphasis of investigation is towards the training programme for specialists in Otorhinolaryngology and continuous medical education (CME). The response rate of the survey was 100 per cent. The duration of training for otorhinolaryngologists ranges from three to seven years and an exit assessment is held in seven countries/regions. The training programmes are modifications of either the British or the American pattern depending on tradition. Documentation of CME is available in eight countries/regions while a defined cycle has been established in only three. Medical/health authorities or professional societies in each country contribute towards its monitoring. Better communication and sharing of experience will improve the training of otorhinolaryngologists in Asia.

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.

Background and Objective: In nasopharyngeal cancer, conventional white light endoscopy does not provide adequate information to detect the flat/small lesion and identify the margin of observable tumor. In the present study, we evaluate the potential of light-induced fluorescence spectroscopic imaging for the localization of cancerous nasopharyngeal tissue., Study Design/materials and Methods: We built a multiple channel spectrometer specifically for the investigation of fluorescence collected by a conventional endoscopic system. Nasopharyngeal fluorescence were measured in vivo from 27 subjects during the routine endoscopy. The biopsy specimens for histologic analysis were taken from the tissue sites where the fluorescence were measured., Results: Two algorithms to discriminate the nasopharyngeal carcinoma from normal tissue were created based on the good correlation between the tissue autofluorescence and histologic diagnosis. For the two-wavelength algorithm, carcinoma can be differentiated from normal tissue with a sensitivity and specificity of 93% and 92%, respectively. For the three-wavelength algorithm with compensation of variation of blood content in tissue, a sensitivity of 98% and specificity of 95% were achieved., Conclusion: Fluorescence endoscopic imaging used with the algorithms developed in this report is an efficient method for detecting the nasopharyngeal carcinoma., (Copyright 2000 Wiley-Liss, Inc.)

Background: This was a prospective study to evaluate the effect of radical external irradiation on inner ear function after treatment of nasopharyngeal carcinoma., Methods: Pure tone audiograms were performed at regular intervals before, after, and up to 4.5 years following completion of radiotherapy., Results: Two hundred ninety-four patients (526 ears) were included. Within 3 months after radiotherapy, deterioration of bone conduction threshold at 4 kHz and pure tone average (average of 0.5 kHz, 1 kHz, and 2 kHz) were noted in 164 ears (31%) and 75 ears (14%), respectively. Patients older than 50 years and ears with threshold below 60 dB at 4 kHz before radiotherapy were significant factors (p < 0.01 and p < 0. 001) associated with a 4 kHz loss. In 40% of these ears, recovery was evident at 2 years. With follow-up for 4.5 years, the probability of significant threshold deterioration increased with time., Conclusion: Sensorineural hearing loss started soon after radiotherapy. Early changes could be reversible while the probability of persistent hearing loss continued to increase., (Copyright 1999 John Wiley & Sons, Inc. Head Neck 21: 547-553, 1999.)

Objective: The purpose of this study was to obtain normal values of nasal geometry in Asian children with no nasal problems using the acoustic rhinometry method., Method: Acoustic rhinometric measurement of the nasal fossae was performed in pediatric patients coming for general surgical operations with no nasal problem., Results: A cohort study of 183 children in an acute care hospital with full elective and emergency surgical services was undertaken. The mean minimal cross-sectional area (MCA), which was functionally important for nasal breathing, was found to be 0.32 cm2 (SD = 0.13) and situated at 1.40 cm (SD = 0.26) from the anterior nare. Normal values for area, length, and volume of the nose in these children as a group and at different ages from 1 to 11 years old were obtained., Conclusions: Acoustic rhinometry was found to be well tolerated by the children. The MCA was confirmed to be situated at the anterior part of the nose and had a positive correlation with an increase in age.

We investigated the actions of various divalent cations on the delayed rectifier K+ currents (IKr) in rabbit sinoatrial node cells using the whole-cell voltage-clamp technique in isotonic K+ solutions. External divalent cations decreased the amplitude of currents, accelerated the time course of deactivation and shifted the activation to positive potentials in a dose-dependent manner. The concentrations for half-maximum inhibition of the steady-state currents (KM) obtained at 0 mV were 0.63, 1.36, 1.65 and 2.16 mM for Ni2+, Co2+, Mn2+ and Ba2+, respectively. The effect was voltage dependent (KM decreased e-fold for 12.2-16.8 mV hyperpolarization), but the dependence did not vary significantly among different cations. Acceleration of the time course of current deactivation by the increase of divalent cation concentration was well fitted by the voltage-dependent block model, and the binding rate constant (k1) was obtained. The binding rates for the ions took the following order: Ni2+ >Co2+ >Mn2+ >Ba2+. The degree of the shift of activation occurred in the same order: Ni2+ >Co2+ >Mn2+ >Ba2+. From these results, we conclude that IKr channels are non-selectively blocked by most divalent cations from the external side and that the binding site is located deep inside the channel, resulting in a steep voltage dependence of the blockade.

We have investigated the effect of external H+ concentration ([H+]o) on the human-ether-a-go-go-related gene (HERG) current (IHERG), the molecular equivalent of the cardiac delayed rectifier potassium current (IKr), expressed in Xenopus oocytes, using the two-microelectrode voltage-clamp technique. When [H+]o was increased, the amplitude of the IHERG elicited by depolarization decreased, and the rate of current decay on repolarization was accelerated. The activation curve shifted to a more positive potential at lower external pH (pHo) values (the potential required for half-maximum activation, V1/2, was: -41.8 mV, -38.0 mV, -33.7 mV, -26.7 mV in pHo 8.0, 7.0, 6.6, 6.2, respectively). The maximum conductance (gmax) was also affected by [H+]o: a reduction of 7.9%, 14.6%, and 22.8% was effected by decreasing pHo from 8.0 to 7.0, 6.6, and 6.2, respectively. We then tested whether this pH effect was affected by the external Ca2+ concentration, which is also known to block HERG channels. When the extracellular Ca2+ concentration was increased from 0.5 mM to 5 mM, the shift in V1/2 caused by increasing [H+]o was attenuated, suggesting that these two ions compete for the same binding site. On the other hand, the decrease in gmax caused by increasing [H+]o was not significantly affected by changing external Ca2+ levels. The results indicate that HERG channels are inhibited by [H+]o by two different mechanisms: voltage-dependent blockade (shift of V1/2) and the decrease in gmax. With respect to the voltage-dependent blockade, the interaction between H+ and Ca2+ is competitive, whereas for the decreasing gmax, their interaction is non-competitive.

These studies were designed to test the hypolipidemic activity of green tea epicatechins (GTE) isolated from jasmine green tea. In Experiment 1, three groups of hamsters were given a semisynthetic diet containing 200 g lard/kg and 1 g cholesterol/kg for 4 wk. The control group received distilled water, and the other two groups received either 15 g/L green tea water extract (GTWE) or 5.0 g/L GTE solution. Both the GTWE and GTE groups had lower concentrations of serum total cholesterol (TC) and triacylglycerols (TG) than the controls (P < 0.05). In Experiment 2, four groups of hamsters received tap water as the drinking fluid, but they were given the same high fat and cholesterol diet supplemented with 0 (control), 1.1, 3.4 or 5.7 g GTE/kg diet. The hypolipidemic effect of jasmine GTE was dose dependent. In Experiment 3, the time-course of changes in serum TC and TG was monitored in hamsters given the high fat diet supplemented with 5.7 g GTE/kg in comparison with that of controls. The hypolipidemic effects of dietary GTE were evident after feeding for 2 wk. Dietary supplementation of GTE did not affect liver fatty acid synthase. However, GTE-supplemented hamsters had higher fecal excretions of total fatty acids, neutral sterols and acidic sterols compared with the control group. In Experiment 4, hamsters were fed nonpurified diet; the control group drank distilled water, and the GTE group drank distilled water containing 5.0 g GTE/L. No differences in activities of 3-hydroxy-3-methyl glutaryl coenzyme A reductase and intestinal acyl CoA:cholesterol acyltransferase were observed. This study suggests that the hypolipidemic activity of GTE is not due to inhibition of synthesis of cholesterol or fatty acid but is most likely mediated by its influence on absorption of dietary fat and cholesterol.