Design of a switching controller for nonlinear systems with unknown parameters based on a fuzzy logic approach

This paper deals with nonlinear plants subject to unknown parameters. A fuzzy model is first used to represent the plant. An equivalent switching plant model is then derived, which supports the design of a switching controller. It will be shown that the closed-loop system formed by the plant and the switching controller is a linear system. Hence, the system performance of the closed-loop system can be designed. An application example on controlling a two-inverted pendulum system on a cart will be given to illustrate the design procedure of the proposed switching controller.

Oral pemphigus vulgaris: a case report and literature update

INTRODUCTION

Pemphigus vulgaris is a rare cause of oral mucosal ulceration.

CLINICAL PICTURE

A 47-year-old Chinese man presented with a 3-month history of oral ulceration. There were no lesions on the skin or other mucosal sites. Histology and immunostaining were consistent with pemphigus vulgaris.

TREATMENT

Systemic and topical corticosteroids were instituted, together with topical antifungals. Conventional periodontal therapy was carried out to improve gingival/oral health.

OUTCOME

Control of oral ulceration was achieved with re-establishment of normal oral function. No other sites to date have been involved.

CONCLUSIONS

Chronic oral ulceration can be the sole manifestation of pemphigus vulgaris, at least initially. Early recognition of this lesion may prevent delayed diagnosis and inappropriate treatment of a potentially chronic dermatological condition.

Apoptosis in primary cardiac tumours

Apoptosis, or programmed cell death, is now recognised as an important cellular event during both normal development and specific disease progression. Apoptosis has been suggested to play a critical role in several cardiovascular diseases, but has not yet been identified as a major influence in primary cardiac tumours. A retrospective review of the achieved material at Chang Gung Memorial Hospital revealed seven patients with cardiac myxoma and one with a tumour originating from the crista terminalis, from January 2002 to December 2002. The medical chart, surgical pathology reports and microscopic slides were available in all cases. All patients, including eight cardiac myxomas and one tumour from crista terminalis, were assessed for apoptosis by terminal deoxynucleotidyl transferase nick-end labelling assay. In this study, apoptosis is well documented in all seven myxoma and has even been reported in tumour from the crista terminalis. Interestingly, apoptosis appears related to the nature of the cell properties rather than the incidence of embolism. In conclusion, apoptosis is important in the progression of the primary cardiac tumours, but the mechanism of cardiac tumour regression still remains uncertain.

Isolation of Salmonella enterica serotype choleraesuis resistant to ceftriaxone and ciprofloxacin

Salmonella enterica serotype choleraesuis (S choleraesuis) usually causes systemic infections in man that need antimicrobial treatment. We isolated a strain of S choleraesuis that was resistant to ceftriaxone and ciprofloxacin from a patient with sepsis. Ciprofloxacin resistance was associated with mutations in gyrA and parC, whereas the ampC gene (bla(CMY-2)), responsible for ceftriaxone resistance, was carried by a transposon-like mobile element. This element was found inserted into finQ of a potentially transmissible 140 kb plasmid, with an 8 bp direct repeat flanking the junction regions. The appearance of this resistant S choleraesuis is a serious threat to public health, and thus constant surveillance is warranted.

Thermodynamic and transport measurements of superconducting Na0.3CoO2.1.3H2O single crystals prepared by electrochemical deintercalation

Superconducting single crystal samples of Na0.3CoO2.1.3H(2)O have been produced using an electrochemical technique which dispenses with the usual bromine chemical deintercalation method. In fully hydrated crystals, susceptibility and specific heat measurements confirm that bulk superconductivity has been achieved. The extracted normal state density of states indicates Fermi-liquid behavior with strong mass enhancement and a modest Wilson ratio. Measurements of H(c2) for H parallel c and H parallel ab reveal significant anisotropy, and the extracted value for the coherence length is about 100 A, consistent with an extremely narrow bandwidth.

Estimation of the incidence of sudden infant death syndrome in Korea: using the capture-recapture method

This study was undertaken to estimate the incidence of sudden infant death syndrome (SIDS) for 2 years from 1997 to 1998 in Korea. The information on SIDS was obtained from three independent sources, the Korean Medical Insurance Corporation data, data from different medical facilities (Korean surveillance on SIDS) and mortality data from the Korean National Statistical Office. A log linear model with no interactions among the 3 sources was used with the selection criteria of both the Akaike Information Criterion and the Bayesian Information Criterion. The 95% confidence intervals of the estimated number of SIDS deaths were calculated using the goodness-of-fit-method. The estimated number of deaths who were not found in any of the sources was 535, and the estimated total number of SIDS deaths was 759. The 95% confidence interval for estimated total number of patients ranged from 642 to 1522. The estimated rate of SIDS cases was 0.56 per 1000 live births per annum, which is similar to the incidence in the USA or Japan.

Effects of Propofol Target-Controlled Infusion on Haemodynamic and Respiratory Changes with Regard to Safety

We investigated the haemodynamic and respiratory effects of propofol target-controlled infusion (TCI) during spontaneous ventilation. We studied 20 patients scheduled for elective orthopaedic surgery who were classified as American Society of Anesthesiologists physical status I. During spontaneous ventilation, haemodynamic, respiratory and electroencephalographic variables were measured. Oxygen flow was maintained at 5 1/min using a semi-closed system and a close-fitting face mask. All measurements were obtained before the propofol TCI and at each propofol effect-site concentration (0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5 and 4.0 μg/ml). Changes in Bispectral Index Score, systolic blood pressure, diastolic blood pressure, end tidal carbon dioxide tension and heart rate were negatively correlated with propofol effect-site concentrations. Despite maintaining oxygen saturation (> 99%), apnoea and blood pressure reductions were abruptly induced as the propofol effect-site concentration increased. We therefore recommend careful monitoring of haemodynamic and respiratory function during spontaneous ventilation using propofol TCI.

Purification, cDNA cloning and expression of an insect defensin from the great wax moth, Galleria mellonella

An insect defensin, named Galleria defensin, was purified from the larval haemolymph of Galleria mellonella immunized against E. coli. The peptide was composed of forty-three amino acid residues containing six cysteines that might be engaged in intramolecular disulphide bridges. The primary structure of Galleria defensin shared about 90.7% identity to that of heliomicin, which was an insect defensin isolated from Heliothis virescens. The full-length cDNA encoding Galleria defensin was cloned from the fat body of the immunized G. mellonella larvae. Northern blot analysis revealed that Galleria defensin was expressed not only in the fat body but also in the midgut against invading bacteria into haemocoel. This is the first report presenting cDNA and expression of an insect defensin in the lepidopteran species.

Optical-spectroscopic detection of spin-exchange interaction pyrochlore molybdates

Optical spectroscopy was used to determine nearest-neighbor spin correlations in pyrochlore molybdates R2Mo2O7 (R=Y, Sm, and Nd), which exhibit ferromagnetic metal to spin-glass insulator transition as the R ion size decreases. Using an analysis based on the orbitally degenerate Hubbard model, we could estimate important physical parameters, such as the effective on-site Coulomb energy U(eff) and the Hund rule exchange coupling J(H). We demonstrated experimentally and theoretically that the effective superexchange interaction between the Mo ions depends on J(H)/U(eff), which determines the phase boundary of the magnetic ground states.

Quantitative polymerase chain reaction assay for serum hepatitis B virus DNA as a predictive factor for post-treatment relapse after lamivudine induced hepatitis B e antigen loss or seroconversion

BACKGROUND AND AIMS

Lamivudine induces favourable virological and biochemical responses but post-treatment relapses are frequent, even in patients with hepatitis B e antigen (HBeAg) loss or seroconversion. The aim of this study was to determine whether extended lamivudine therapy for up to 12 months after HBeAg loss/seroconversion could decrease the risk of post-treatment virological relapse. In addition, we monitored serum hepatitis B virus (HBV) DNA levels using a quantitative polymerase chain reaction (PCR) assay during extended lamivudine therapy and analysed predictive factors for post-treatment relapse.

PATIENTS AND METHODS

A total of 49 patients who exhibited HBeAg loss/seroconversion during lamivudine therapy received extended lamivudine therapy for six months (group 1, n=23) or 12 months (group 2, n=26) after HBeAg loss/seroconversion. Serum HBV DNA levels were quantified by a PCR based assay at the time of HBeAg loss/seroconversion, and at cessation of therapy.

RESULTS

Post-treatment virological relapse rates at two years were 59% in group 1 and 50% in group 2. Age, time interval to HBeAg loss/seroconversion, and serum HBV DNA levels at the time of cessation of therapy were independent predictive factors for post-treatment relapse. The post-treatment relapse rate was 37% at two years in patients with serum HBV DNA levels of <200 copies/ml but 73% in those with > or =10(3) copies/ml.

CONCLUSIONS

Extended lamivudine therapy for up to 12 months did not decrease the rate of post-treatment virological relapse, and monitoring of serum HBV DNA by a quantitative PCR method was helpful in predicting post-treatment relapse.

Use of the Keele injector for sample introduction for gas chromatographic analysis of vinclozolin in lettuces

We examined a Keele injector for sample introduction for gas chromatographic analysis of vinclozolin treated in lettuces. Samples in milligram quantity were introduced into a glass tube in a Keele injector at a gas chromatograph injection port. The glass tube was then crushed to allow the sample to carry onto a capillary column in a normal manner. The standard calibration curve for quantitative detection of vinclozolin was obtained by determining vinclozolin spiked in samples at variable concentrations. The calibration curve showed a linear response to vinclozolin ranging from 0.05 to 1.0 microg/g, giving a slope value of 174.8, the y-intercept value of -2.8146 and the mean r2-value of 0.9994. Limit of quantification for vinclozolin was 0.05 microg/g by this method, comparable to 0.01 microg/g by a normal injector. When samples treated previously with vinclozolin were determined by the Keele injector, vinclozolin was found to be about 30% lower as compared to a normal method, suggesting about 70% recovery of the spiked vinclozolin by the Keele injector. From these results, the Keele injector was suggested to be potential for sample introduction in gas chromatographic analysis of vinclozolin in lettuce samples.

Squamous cell carcinoma in vitiligo lesion after long-term PUVA therapy

Photochemotherapy using psoralen and ultraviolet (UV)A irradiation (PUVA) is a useful treatment method for vitiligo. However, long-term PUVA therapy may cause several adverse effects including skin cancer, especially squamous cell carcinoma (SCC). We describe a case of SCC in vitiligo lesion after long-term PUVA therapy.

Prenatal sonographic diagnosis of isolated agnathia: a case report

Agnathia is a rare malformation characterized by the absence of the mandible, microstomia, aplasia or hypoplasia of the tongue, and low-set or medially fused ears. It occurs alone or in combination with a variety of malformations such as holoprosencephaly. All previous cases of the prenatal diagnosis of agnathia have been accompanied with fatal anomalies. We report here the first case of isolated agnathia, which was diagnosed by prenatal sonography at 32 weeks of gestation. In this case, prenatal sonographic examination showed the severe defect of the chin, small opening of the mouth and severe polyhydramnios. There was no sonographic evidence of holoprosencephaly or anomalies in other organ systems. The diagnosis was confirmed postnatally.

Comparative study on conventional and low-flow nebulizers for arsenic speciation by means of microbore liquid chromatography with inductively coupled plasma mass spectrometry

The performance of conventional and low-flow nebulizer systems with liquid chromatography in differentiating four arsenic species in urine was evaluated. Two low-flow (DIN and MCN) chamber assemblies and a conventional (CFN) nebulizer-spray chamber assembly were compared in the hyphenation of anion-exchange microbore liquid chromatography with inductively coupled plasma mass spectrometry. Under optimal analytical conditions, the detection limits of the four arsenic species were 0.2-0.6 ng ml(-1) for all the nebulizer systems tested. The chromatographic resolution was best in the case of DIN due to its minimal off-column dead volume and superior transport efficiency. Four arsenic species were determined in the certified reference materials NIST SRM 2670E and 2670N.

Design of novel peptide ligands which have opioid agonist activity and CCK antagonist activity for the treatment of pain

Disease states such as neuropathic pain offer special challenges in drug design due to the system changes which accompany these diseases. In this manuscript we provide an example of a new approach to drug design in which we have modified a potent and selective peptide ligand for the CCK-2 receptor to a peptide which has potent agonist binding affinity and bioactivity at delta and mu opioid receptors, and simultaneous antagonist activity at CCK receptors. De novo design based on the concept of overlapping pharmacophores was a central hypothesis of this design, and led to compounds such as H-Tyr-DPhe-Gly-DTrp-NMeNle-Asp-Phe-NH(2) (i.e., RSA 601) which have the designed properties.

A distinctive type of metaphyseal chondrodysplasia with characteristic thickening of the distal ulna and radius: possible metaphyseal chondrodysplasia-Rosenberg

We report an 8-year-old boy with a distinctive form of metaphyseal chondrodysplasia (MCD). He presented with moderate disproportionate short stature and bony swelling of his wrists, knees, and ankles. There were severe metaphyseal abnormalities with a honeycomb appearance affecting the distal tibiae and fibulae, proximal tibiae, distal femurs, distal ulnae and radii, and both hands. His thoracolumbar spine was normal. Radiological examination of the mother's forearms revealed widening of the distal radii and short ulnae with hypoplastic distal ends. Rosenberg and Löhr [1986: Eur J Pediatr 145:40-45] reported a four-generational kindred in which affected members had thickening of the wrist proximal to the styloid process of the ulna and thickening of the dorsum sellae. Although many of the radiographic features of this patient are those of MCD-Rosenberg, the skeletal features of our patient do not appear to represent any known classified forms of MCD.

1H fast MAS NMR studies of hydrogen-bonding interactions in self-assembled monolayers

The structures formed by the adsorption of carboxyalkylphosphonic acids on metal oxides were investigated by (1)H fast magic angle spinning (MAS), heteronuclear correlation (HETCOR), and (1)H double-quantum (DQ) MAS solid-state NMR experiments. The diacids HO(2)C(CH(2))(n)PO(3)H(2) (n = 2, 3, 11, and 15) were adsorbed on TiO(2) and two types of ZrO(2) powders having average particle sizes of 20, 30, and 5 nm, respectively. Carboxyalkylphosphonic acids bind selectively via the phosphonate group, forming monolayers with pendant carboxylic acid groups. Whereas dipolar coupled P-OH protons are detected on TiO(2), there are only isolated residual P-OH groups on ZrO(2), reflecting the relative binding strengths of phosphonic acids on these two substrates. From a comparative (1)H MAS NMR study with an analogous monolayer system, HO(2)C(CH(2))(7)SH coated gold nanoparticles, the hydrogen-bonding network at the monolayer/air interface is found to be quite disordered, at least for SAMs deposited on nonplanar substrates. Whereas only hydrogen-bonded homodimers occur in the bulk diacids, hydrogen bonding between the carboxylic and phosphonic acid groups is present in multilayers of the diacids on the ZrO(2) nanopowder.

Ganglioneuroblastoma presenting as dilated cardiomyopathy

We report an unusual presentation of ganglioneuroblastoma with features of dilated cardiomyopathy in a 22 month old girl. She was admitted with cardiomegaly; during echocardiography a suspicious abdominal mass was detected by chance. Further imaging studies, including abdominal ultrasonography and spiral computed tomography, revealed a solid mass originating in the right adrenal gland. Metabolic studies and pathological findings were compatible with ganglioneuroblastoma. Following tumour removal and supportive therapy for cardiomyopathy, her clinical condition and laboratory findings improved. Although ganglioneuroblastoma with features of dilated cardiomyopathy is rare, because neurogenic tumours may be involved in its development, measurement of catecholamines in children with dilated cardiomyopathy is strongly recommended.

Electron and orbital correlations in Ca2-xSrxRuO4 probed by optical spectroscopy

The optical conductivity spectra of the quasi-two-dimensional Ca2-xSrxRuO4 (0.0< or =x< or =2.0) system were investigated. In the Mott insulating state, two electron correlation-induced peaks were observed about 1.0 and 1.9 eV, which could be explained using the 3-orbital Hubbard model. The low frequency peak showed a shift toward higher frequency as temperature was lowered, indicating that electron-phonon interactions play an important role in the orbital arrangements. From the systematic analysis, it was suggested that the antiferro-orbital and the ferro-orbital ordering states could coexist.

Requirement of metabolic activation for estrogenic activity of Pueraria mirifica

A wide range of chemicals derived from plant and human-made xenobiotics are reported to have hormonal activities. The present study was performed to examine the estrogenic effect of Kwao Keur, Pueraria mirifica (PM), that has been used as a rejuvenating folk medicine in Thailand, using recombinant yeast, MCF-7 cell proliferation and HepG2 cell transient transfection assay. In recombinant yeast assay, 0.025, 0.25, 2.5, 25, 2.5 x 10(2), 2.5 x 10(3), 2.5 x 10(4) ng/ml concentrations of PM did not show any estrogenic activities, while 10(-9) of 17 beta-estradiol (positive control) showed high estrogenic activity. Estrogenic activities were induced at 2.5 ng/ml to 25 microg/ml concentrations of PM in a dose-dependent manner on MCF-7 cells and the estrogenic effect of PM was blocked by tamoxifen treatment, a well-known anti-estrogen. PM also showed estrogenic effect on human hepatoma cell line, HepG2 cells, containing estrogen receptor and luciferase reporter gene. Taken together, PM in itself may have no estrogenicity in yeast system, but it has estrogenicity in MCF-7 & HepG2 cells that have human metabolic enzymes. The results indicated that PM may require metabolic activation for estrogenic activity.

Adult-to-adult living donor liver transplantation at the Asan Medical Center, Korea

Between February 1997 and December 2001, 311 adult-to-adult living donor liver transplants (A-A LDLTs) were performed at the Asan Medical Center for patients above 20 years of age. Indications for A-A LDLT were: chronic hepatitis B (203), chronic hepatitis C (5), hepatocellular carcinoma (64), alcoholic cirrhosis (9), cryptogenic cirrhosis (4), secondary biliary cirrhosis (5), primary biliary cirrhosis (1), Wilson' s disease (2), autoimmune hepatitis (1), hepatic tuberculosis (1), cholangiocarcinoma (1), fulminant hepatic failure (14) and primary non-function of cadaveric liver graft (1). Of 311 A-A LDLTs, 36 were of medical high urgency, 20 were for acute and subacute hepatic failure, 15 were for hepato-renal syndrome and 1 was for primary non-function. Recipient age ranged from 27 to 64 years. Donor age ranged from 16 to 62 years. There was no donor mortality. Implanted liver grafts were categorized into seven types: 175 modified right lobe (MRL), 70 left lobe, 32 right lobe, 20 dual grafts, 10 left lobe plus caudate lobe, three extended right lobe and one posterior segment. In MRL, the tributaries of the middle hepatic vein were reconstructed by interpositioning a vein graft. Indication for dual graft implantation was the same as single graft A-A LDLT, and four of 20 were emergency cases. Of 20 dual grafts, 14 received two left lobes, four received a left lobe and a lateral segment, one received a right lobe and a left lobe and one received a lateral segment and a posterior segment. Graft volume ranged from 28% to 83% of the standard liver volume of the recipients. There were 33 (10.6%) in-hospital mortalities (< 4 months) among the 310 patients after 311 A-A LDLTs. Of the 36 patients receiving emergency transplants, 31 survived. These encouraging results justify the expansion of A-A LDLT in coping with increasing demands, even in urgent situations. We have aimed to introduce the establishment of the efficacy of A-A LDLT in various end-stage chronic and acute liver diseases, as well as new technical advances to overcome small graft-size syndrome by using dual-graft implantation and MRL, both of which were first developed in our department.

PCR-RFLP based molecular typing of enteroviruses isolated from patients with aseptic meningitis in Korea

We have evaluated PCR-RFLP as a practical method for rapid typing of enteroviruses causing aseptic meningitis in Korea. Through blind examination of 80 clinical isolates from patients with aseptic meningitis, we have compared the results of conventional serotyping with PCR-RFLP based genotyping, which was developed for this study. Among the 80 case isolates, which had been previously typed by routine neutralization test, only 42 cases (52.5%) were matched with typing by PCR-RFLP. The result clearly demonstrated that the enterovirus serotype does not coincide with the genotype. Therefore, the classification of enteroviruses by genotyping with PCR-RFLP, although rapid and simple, may be complicated by regional or seasonal differences. However, the PCR-RFLP method developed in this study is applicable to the epidemiological study of enteroviruses when regional or seasonal differences exist, and is useful in identifying the source of an infection.

Surrogate estimates of insulin sensitivity in Chinese diabetic patients and their offspring

AIMS

To evaluate the relationship between surrogate measures of insulin sensitivity and results from euglycaemic insulin clamp in Chinese diabetic patients and their offspring.

METHODS

The study included 59 volunteers from 20 diabetic families. Each participant completed a 75-g oral glucose tolerance test (OGTT) and a euglycaemic insulin clamp. We tested the correlation of surrogate measures of insulin sensitivity with M-values and M/I ratios (the amount of glucose infused during 90-120 min of the clamp was defined as M, and the mean values of plasma insulin during 90-120 min as I) from the euglycaemic insulin clamp. These measures included fasting insulin (FPI), insulin at 120 min of OGTT, insulin area under the curve of OGTT, fasting glucose-to-insulin ratio, homeostasis model assessment for insulin sensitivity (HOMA-IR and HOMA %S) and the Matsuda-DeFronzo index from OGTT.

RESULTS

The Matsuda-DeFronzo index closely correlated to M-value and M/I in 21 diabetic, 38 non-diabetic individuals and the 59 participants overall (with M-value, r = 0.68, 0.84 and 0.84; with M/I, r = 0.71, 0.72 and 0.75, respectively, all P < 0.001). Without OGTT, HOMA %S was a good surrogate index for diabetic (correlated to M-value and M/I, r = 0.71 and 0.68, P = 0.001) and for non-diabetic subjects (to M-value, r = 0.73; to M/I, r = 0.55, both P < 0.001). FPI was as good as HOMA %S and Matsuda-DeFronzo index.

CONCLUSIONS

The Matsuda-DeFronzo index, HOMA %S and FPI are good surrogate estimates of insulin sensitivity in Chinese diabetic subjects and their offspring.

Nickel-catalyzed cross-coupling of bromophenols with Grignard reagents in the solid phase synthesis

Polymer-bound substituted bromophenols were found to readily undergo a Ni(0)-catalyzed cross-coupling reaction with Grignard reagents to give a variety of substituted phenols and hydroquinones, after cleavage from the support, in moderate to high yields. The requisite bromophenol derivatives, which were prepared from the corresponding phenols and hydroquinone using BTMA Br3 or TBA Br3, were attached to the solid support by the Mitsunobu reaction.

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

BACKGROUND

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

AIM OF THE STUDY

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

METHODS

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

RESULTS

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

CONCLUSION

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

Expression of epidermal growth factor receptor in head and neck cancers correlates with clinical progression: a multicentre immunohistochemical study in the Asia-Pacific region

AIMS

With ongoing efforts to target the epidermal growth factor receptor (EGFR)-mediated tumour growth in the treatment of selected human malignancies, there is a need to determine the expression levels of EGFR and to evaluate its prognostic value in various malignancies in the Asia-Pacific region.

METHODS AND RESULTS

A total of 172 patients with head and neck squamous cell carcinomas from Australia, Hong Kong, Singapore, and Taiwan were selected for EGFR detection. Immunohistochemical staining was performed to evaluate EGFR expression. EGFR expression was present in 88.4% (152/172) of all cases tested. Specifically, EGFR expression was found in 91.3% (42/46), 84.6% (22/26), 84.1% (37/44), 96.0% (24/25), and 87.1% (27/31) cases of head and neck squamous cell carcinomas from the oral cavity, oropharynx, nasopharynx, hypopharynx, and larynx, respectively. The results demonstrate a stronger EGFR expression in T4 tumours (P=0.017) and later clinical stages (P=0.016). No significant correlation was seen with risk factors, primary tumour site and ethnicity.

CONCLUSIONS

The majority of head and neck squamous cell carcinomas express EGFR, indicating the importance of studying the efficacy of anti-cancer therapy through this pathway. The results also show similar rates of receptor expression in head and neck squamous cell carcinoma patients from our region compared with other parts of the world.

Effect of agitation intensity on the exo-biopolymer production and mycelial morphology in Cordyceps militaris

AIMS

The influence of agitation intensity on Cordyceps militaris morphology and exo-biopolymer production was investigated in a 5 litre stirred vessel using a six-blade Rushton turbine impeller.

METHODS AND RESULTS

The mycelial morphology of C. militaris was characterized by means of image analysis, which included mean diameter, circularity, roughness and compactness of the pellets. The morphological parameters of the pellets grown under different stirring conditions were significantly different, which correspondingly altered exo-biopolymer production yields.

CONCLUSIONS

The compactness of the pellets was found to be the most critical parameter affecting exo-biopolymer biosynthesis; more compact pellets were formed at 150 rev min(-1) with maximum exo-biopolymer production (15 g l(-1)).

SIGNIFICANCE AND IMPACT OF THE STUDY

The results of this study suggest that morphological change of pellets is a good indicator for identifying the cell activity for exo-biopolymer production.

Exacerbation of insulin resistance and postprandial triglyceride response in newly diagnosed hypertensive patients with hypertriglyceridaemia

The purpose of the study is to examine the differences in insulin resistance and postprandial triglyceride (TG) response between hypertensive patients with or without hypertriglyceridaemia. The study is a comparative cohort study with matching. Thirty-one newly diagnosed hypertensive patients without any medication were recruited from a health survey. The participants were further divided into two groups: those with fasting TG <2.26 mmol/L, and those with TG between 2.26 and 5.65 mmol/L. Both groups were matched in age, sex, body mass index and waist circumference. Each patient received a 75-g oral glucose tolerance test, an insulin suppression test, and a 1000 kcal high fat mixed meal test. The hypertriglyceridaemic hypertensive patients had significantly higher fasting insulin, 2-h plasma glucose, 2-h insulin, and steady-state plasma glucose (SSPG) (13.16 +/- 1.87 vs 9.76 +/- 3.18 mmol/L). They also had a greater postprandial TG response to the challenge of mixed meal (DeltaAUC 20.76 +/- 10.06 vs 7.97 +/- 3.18 mmol 8 h/L). The postprandial TG response was closely correlated (r = 0.72-0.95, P < 0.0001) with fasting TG in all hypertensive patients. Both fasting TG levels and postprandial TG response were significantly (P < 0.05) correlated with SSPG. In conclusion, the hypertensive patients with hypertriglyceridaemia were more insulin resistant than those without it. Exacerbation of postprandial hypertriglyceridaemia was identified in these patients. The TG response to the challenge of high fat meal was significantly correlated with fasting TG and insulin resistant in them. The results provide a rationale for the alleviation of insulin resistance and hypertriglyceridaemia in these atherosclerosis-prone hypertensive patients.

Marie Unna hypotrichosis in a Chinese family

Marie Unna hypotrichosis is a rare, autosomal dominant hypotrichosis characterized by sparse or absent hair at birth with regrowth of coarse, wiry hair from childhood, followed by progressive loss on approaching puberty. We report a Chinese mother and child seen at our skin center with features of Marie Unna hypotrichosis. The family pedigree showed two affected sisters and one affected brother, consistent with an autosomal dominant mode of inheritance. The clinical, genetic, histologic, and ultrastructural features were consistent with the diagnosis of Marie Unna hypotrichosis. This is the first Chinese family reported.

A dominant antigenic region of the hantaan virus nucleocapsid protein is located within a amino-terminal short stretch of hydrophilic residues

The nucleocapsid (N) protein of the Hantaan virus (HTNV) is a major viral antigen that induces a strong antibody response during the acute phase of infection. By immunoblot analyses of the recombinant N proteins using human sera of the hemorrhagic fever with renal syndrome (HFRS), we have confirmed previous finding by other investigators of the presence of a highly antigenic region near the amino terminus of the HTNV N protein. We have further located the antigenic region within a short stretch of hydrophilic sequences between the 26 and the 46th amino acid residues. The recombinant glutathione S-transferase fusion proteins containing this region was expressed as a soluble form in a large quantity in Escherichia coli, and purified by a single-step affinity chromatography. The recombinant antigen also showed a similar, but a weaker reactivity with human antisera to Seoul virus (SEOV), the virus most closely related to HTNV.

Maternal thyrotoxicosis causing central hypothyroidism in infants

We describe three infants born to mothers with poorly controlled Graves' disease, who developed transient central hypothyroidism in the immediate postnatal period. Suppression of the fetal pituitary-thyroid axis may be due to placental transfer of thyroxine from the hyperthyroid mother. This may persist for months postnatally, necessitating treatment to optimise neurodevelopmental outcome.

Epidemiology of 21-hydroxylase deficiency in Singapore

We report the incidence and epidemiology of 21-hydroxylase deficiency in Singapore, based on a retrospective study of all known patients diagnosed with classical 21-hydroxylase deficiency in the past 21 years. The database was obtained from the case registry and questionnaire methodology, with 100% coverage of all practising pediatricians in Singapore. There were 42 patients affected with 21-hydroxylase deficiency in 964,558 live births over 21 years, comprising 64.3% salt wasters and 35.7% simple virilizers, of whom 50.0% were males and 50.0% females. The incidence of classical 21-hydroxylase deficiency is 4.5 per 100,000 live births, with a carrier frequency of 1:76, and a gene frequency of 0.0067. Although retrospective studies have inherent limitations, the gender and phenotype ratios suggest that the data provide a crude incidence level. This study underscores the necessity for prospective neonatal screening, so that the benefits of early diagnosis and treatment can be realized.

A novel melanocortin 3 receptor gene (MC3R) mutation associated with severe obesity

The melanocortin 3 receptor (MC3R) plays a critical role in weight regulation as demonstrated in mouse models. We describe a novel mutation Ile183Asn (T548A) found in heterozygosity in a 13-year-old obese girl and her father.

METHODS

The MC3R gene was sequenced in 41 unrelated obese children, and 121 DNA samples from non-obese individuals were analysed for this novel sequence variant by allele-specific polymerase chain reaction (PCR). The genotypes of four family members of the pedigree were also analysed by allele-specific PCR.

RESULTS

Ile183Asn was found in the proband and her father, though all four family members were obese. The sequence variant was not found in 121 control samples. The proband has high percentage body fat (49%), but the father's percentage body fat was only 30%. There were no distinguishing phenotypic features. Insulin sensitivity was significantly higher compared to the 40 other obese subjects without MC3R gene mutations.

DISCUSSION

The difference in phenotypes between the two related heterozygotes, and the observation of obesity in other family members without the mutation suggests that obesity results from a varying combination of environmental, behavioural and multiple genetic factors (other than MC3R), even within the same family.

Tyrosine phosphatase-like protein (IA-2) and glutamic acid decarboxylase (GAD65) autoantibodies: a study of Chinese patients with diabetes mellitus

Type 1 diabetes in most Asian populations may not have a salient autoimmune basis when assessed with single determinations of the major markers, islet cell antibodies (ICAs) and glutamic acid decarboxylase antibodies (GAD65ab). With the inclusion of antibodies to tyrosine phosphatase-like protein IA-2 (IA-2ab) as an additional major marker, we re-examined autoimmune diabetes in a group of Chinese patients. We studied 272 subjects at various stages of disease with blood samples procured for biochemical analysis. ICAs were measured by immunofluorescence, GAD65ab and IA-2ab by radioimmunoassay. Sixty-seven patients fulfilled clinical diagnosis of type 1 diabetes and the remaining 205 patients were type 2. Prevalence of single autoantibody type in recent-onset type 1 diabetes ( < 1 year duration; n = 47) showed 10.6% with ICAs, 44.7% GAD65ab and 36.2% IA-2ab. GAD65ab account for more than two-thirds of the markers found in type 1 diabetes. Combined analysis further showed that 51.1% had at least one antibody type, 31.9% with two or more antibodies and 8.5% with all three antibodies. Islet autoimmunity presence in childhood-onset type 1 diabetes improved with the addition of IA-2ab, though less impact was seen in the adult-onset. Similarly, combined analysis for type 2 patients with recent diabetes showed a modest increase to 13% with islet autoimmunity compared to 8% when assessed by GAD65ab alone. Combining IA-2ab and GAD65ab assays results detected slightly more immune-mediated diabetes, compared to using a single GAD65ab determination. Non-autoimmune causes need to be considered in the pathogenesis of type 1 diabetes in Chinese, particularly in adults.

An activating mutation of the thyrotropin receptor gene in hereditary non-autoimmune hyperthyroidism

The thyroid stimulating hormone (TSH) receptor gene displays a diverse spectrum of activating and inactivating mutations. We report a germline activating mutation M463V of the TSH receptor gene in two siblings with hereditary non-autoimmune hyperthyroidism. The onset of disease in the affected members of the pedigree occurred during childhood or adolescence. The significance of diagnosing activating TSHR mutations lies in therapeutic management and genetic counseling; thyroid ablation is advocated as first line treatment.

Molecular analysis of CYP-21 mutations for congenital adrenal hyperplasia in Singapore

BACKGROUND

Congenital adrenal hyperplasia arising from 21-hydroxylase deficiency is associated with mutations in the CYP21 gene on chromosome 6p. This is the first report on the mutational spectrum of the CYP21 gene in Singapore.

METHODS

To catalogue the mutations, ten exons of the CYP21 gene from 28 Singaporean patients were analyzed by PCR amplification and direct sequencing.

RESULTS

Common mutations in descending order were the intron 2 splice site mutation (32.7% of the alleles), the I172N mutation (23.1% of the alleles), and the R356W mutation (19.2% of the alleles). Two potentially novel mutations were discovered: (1) duplication of 111 bp from codon 21 to codon 57 (exon 1) and (2) missense mutation (L261P, exon 7). There was generally a good genotype-phenotype correlation, allowing accurate prediction of the disease severity.

Lack of adverse effects in the F1 offspring maternally exposed to genistein at human intake dose level

Recently there has been growing concern about endocrine disrupters (ED) derived from synthetic and natural chemicals. It has been argued that ED might cause developmental disorders in the next generations of animals and humans; however, this is still unclear. Therefore, we investigated whether maternal exposures to genistein (GEN) during gestation and lactation alter reproductive organs in the F1 offspring compared with those in 17beta-estradiol (E2)-maternally exposed F1 offspring. Pregnant Sprague-Dawley rats were treated orally with 0.4 mg/kg, 4.0 mg/kg GEN or 10 microg/kg E2. Maternal or neonatal effects on the number of live pups, implantation sites, sex ratio, anogenital distance, eyelid opening/vaginal opening and body weight of live pups were not altered by GEN or E2. The weights of reproductive organs at the adult stage F1 offspring were not altered by maternal exposure to GEN, except for the ventral prostate. However, the weight of the seminal vesicle was significantly decreased from postnatal day (PND) 21 to PND 70 in E2-treated offspring. Sperm analyses, cell count in seminiferous tubules and follicular development in the ovary were not altered by maternal exposure to GEN. Taken together, these results suggest that maternal exposure of GEN might not have adverse effects on the reproductive organs in the F1 offspring at the human intake dose level.

Identification of essential active-site residues in ornithine decarboxylase of Nicotiana glutinosa decarboxylating both L-ornithine and L-lysine

The cDNA encoding ornithine decarboxylase (ODC; EC 4.1.1.17), a key enzyme in putrescine and polyamine biosynthesis, has been cloned from Nicotiana glutinosa (GenBank AF 323910), and was expressed in Escherichia coli. The amino acid sequence of N. glutinosa ODC showed 90% identity with Datura stramonium ODC, and 44% identity with human ODC. N. glutinosa ODC did not possess the PEST sequence [a sequence rich in proline (P), glutamic acid (E), serine (S) and threonine (T) residues] found in mammalian ODCs, which are thought to be involved in rapid degradation of the protein. The purified ODC was a homodimeric protein, having a native M(r) of 92000. Kinetic studies of ODC showed that N. glutinosa ODC decarboxylated both l-ornithine and l-lysine with K(m) values of 562 microM and 1592 microM at different optimal pH values of 8.0 and 6.8 respectively. ODC activity was completely and irreversibly inhibited by alpha-difluoromethylornithine (K(i) 1.15 microM), showing a competitive inhibition pattern. Site-directed mutagenesis was performed on ODC to introduce mutations at conserved lysine (Lys(95)) and cysteine (Cys(96), Cys(338) and Cys(377)) residues, chosen by examination of the conserved sequence, which were proven by chemical modification to be involved in enzymic activity. Except for Cys(96), each mutation caused a substantial loss in enzyme activity. Most notably, Lys(95) increased the K(m) for l-ornithine by 16-fold and for l-lysine by 3-fold, with 100-fold and 2.8-fold decreases in the k(cat) for ODC and lysine decarboxylase (LDC) activity respectively. The Cys(377)-->Ala mutant possessed a k(cat) that was lowered by 23-fold, and the K(m) value was decreased by 1.4-fold for l-ornithine. The three-dimensional model of ODC protein constructed on the basis of the crystal structure of Trypanosoma brucei, mouse and human ODCs localized the four residues in the active-site cleft. This is the first work carried out on active-site residues of plant ODC, where ODC and LDC activities occur in the same catalytic site.

Role of reactive oxygen species in apoptosis induced by N-ethylmaleimide in HepG2 human hepatoblastoma cells

We have previously reported that N-ethylmaleimide induces apoptosis through activation of K(+), Cl(-)-cotransport in HepG2 human hepatoblastoma cells. In this study, we investigated the role for reactive oxygen species as a mediator of the apoptosis induced by N-ethylmaleimide. N-ethylmaleimide induced a significant elevation of intracellular level of reactive oxygen species. Treatment with antioxidants (N-acetyl cysteine, N,N'-diphenyl-p-phenylenediamine) which markedly suppressed generation of reactive oxygen species, significantly inhibited the N-ethylmaleimide-induced activation of K(+), Cl(-)-cotransport and apoptosis. Inhibitors of NADPH oxidase (diphenylene iodonium, apocynin, D-(+)-neopterine) also significantly blunted the generation of reactive oxygen species, activation of K(+), Cl(-)-cotransport and apoptosis induced by N-ethylmaleimide. These results suggest that reactive oxygen species generated through activation of NADPH oxidase may play a role in the N-ethylmaleimide-induced stimulation of K(+), Cl(-)-cotransport and apoptosis in HepG2 cells.

The complete DNA sequence of the mitochondrial genome of the self-fertilizing fish Rivulus marmoratus (Cyprinodontiformes, Rivulidae) and the first description of duplication of a control region in fish

We isolated Rivulus marmoratus mitochondrial DNA by long-polymerase chain reaction with conserved primers, and sequenced it with 36 sets of internal conserved primers, which were designed from the extensive sequence similarities of mitochondrial DNA from several fish species. The R. marmoratus mitochondrial DNA has 17,329 bp with a conserved structural organization compared to those of other fish. Rivulus marmoratus mitochondrial DNA also has two nearly identical control regions. The basic characteristics of the R. marmoratus mitochondrial genome are discussed.

Anticarcinogenic effect of Panax ginseng C.A. Meyer and identification of active compounds

The failure to improve the five-year survival rate of cancer patients, from one in three in the 1960s to one in two in the 1970s, stimulated awareness of the importance of primary prevention of cancer. Korean investigators carried out extensive long-term anticarcinogenicity experiments with 2000 newborn mice to investigate whether Panax ginseng C.A. Meyer inhibited carcinogenesis induced by several chemical carcinogens in 1978. There was a 22% decrease (p<0.05) in the incidence of urethane induced lung adenoma by the combined use of red ginseng extract. In the group sacrificed at 56 weeks after the treatment with aflatoxin B1, the incidence of hepatoma significantly decreased to 75% by the addition of red ginseng extract (p<0.05). The result showed that natural products can provide hope for human cancer prevention. By the newly established '9 week medium-term anticarcinogenicity test model of lung tumors in mice' (Yun's model), we confirmed significant anticarcinogenic effects of powders and extracts of the 6- yr-old dried fresh ginseng, 5- and 6-yr old white ginsengs, and 4-, 5-, and 6-yr old red ginseng. We also demonstrated that the anticarcinogencity of ginseng was more prominent in aged or heat treated extracts of ginseng and red ginseng made by steaming. To investigate the active components for cancer prevention, several fractions of 6-yr old fresh ginseng and red ginseng, four semi-synthetic ginsenoside Rh1, Rh2, Rg3 and Rg5, major saponin components in red ginseng, were prepared. Among the ginsenosides, Rg3 and Rg5 showed statistically significant reduction of lung tumor incidence and Rh2 had a tendency of decreasing the incidence. Ginsenoside Rg3, Rg5 and Rh2 were found to be active anticarcinogenic compounds. Rg3, Rg5 and Rh2 are active components in red ginseng, and they prevent cancer either singularly or synergistically.

Three functional isoforms of GAR-2, a Caenorhabditis elegans G-protein-linked acetylcholine receptor, are produced by alternative splicing

We have previously isolated a cDNA clone from Caenorhabditis elegans that encodes a novel form of G-protein-linked acetylcholine receptor, termed GAR-2. GAR-2 is similar to but pharmacologically distinct from muscarinic acetylcholine receptors. Here we report the identification of two gar-2 cDNA clones that are different from the previous one. These newly identified cDNAs encode polypeptides of 664 and 627 amino acids, whereas the previous one encodes a polypeptide of 614 amino acids. The three GAR-2 isoforms, which differ only in the third intracellular loop, arise from alternative splicing. Electrophysiological analyses using the Xenopus oocyte system showed that all three GAR-2 isoforms couple to the activation of G-protein-gated inwardly rectifying K+ (GIRK1) channel with similar drug specificity. Our results indicate that alternative splicing plays an important role in promoting molecular diversity of G-protein-linked acetylcholine receptors in C. elegans.

Multimerization of phosphorylated and non-phosphorylated ArcA is necessary for the response regulator function of the Arc two-component signal transduction system

To adapt to anaerobic conditions, Escherichia coli operates the Arc two-component signal transduction system, consisting of a sensor kinase, ArcB, and a response regulator, ArcA. ArcA is converted to the active form, phosphorylated ArcA (ArcA-P), by ArcB-mediated phosphorylation. The active ArcA-P binds to the promoter regions of target genes, thereby regulating their transcriptional activities. The phosphoryl group of ArcA-P is unstable with a half-life of 30 min. However, we were able to inhibit the dephosphorylation for more than 12 h by the addition of EDTA; this allowed us to characterize ArcA-P. Gel-filtration and glycerol sedimentation experiments demonstrated that ArcA exists as a homo-dimer. ArcA phosphorylated by either ArcB or carbamyl phosphate multimerizes to form a tetramer of dimers; this multimer binds to the ArcA DNA binding site. Isoelectric focusing gel electrophoresis and nitrocellulose-filter binding analyses indicated that the ArcA multimer is composed of both ArcA-P and ArcA in a ratio, 1:1. The ArcA(D54E) mutant protein was unable to be phosphorylated by ArcB. This defect resulted in the inability of ArcA(D54E) to form a multimer or to bind to the ArcA DNA binding site. These results indicate that phosphorylation of ArcA induces multimerization prior to DNA binding, and the multimerization is a prerequisite for binding. Our results suggest a novel model that phosphorylation of ArcA by ArcB regulates multimerization of ArcA, which in turn functions as a response regulator.

Cyclic pamidronate infusion improves bone mineralisation and reduces fracture incidence in osteogenesis imperfecta

A prospective open study was performed to determine the efficacy and safety of pamidronate in improving bone mineralisation and reducing fracture incidence in osteogenesis imperfecta (OI). Intravenous pamidronate was administered at 1.5 mg/kg bi-monthly to six children with OI, over 12-23 months. The number of fractures decreased from median of 3 (range 1-12) to 0 fractures/year (range 0-4) (P<0.05). After 12 months of treatment, there was significant improvement in areal bone mineral density (BMD) z-scores of the lumbar spine from median of -2.40 (range -3.20 to -1.67) to -1.90 (range -2.38 to -0.91) (P<0.05) and in the volumetric BMD which increased from median of 0.095 to 0.146 g/cm3 (P<0.05). Urine N-telopeptide levels (bone resorption marker) decreased from a median of 461.5 bone collagen equivalent/creatinine (BCE/Cr) (range 129-721 BCE/Cr) to 223.5 BCE/Cr (range 107-312 BCE/Cr) (P<0.05) and serum alkaline phosphatase (ALP) (bone formation marker) from a median of 230.0 U/l (range 148-305 U/l) to 133.5 U/l (range 79-233 U/l) (P<0.05), reflecting reduced bone turnover. This may represent a net reduction in bone resorption and provides a biochemical explanation for the increase in bone mineralisation. Height standard deviation scores were not affected and there were no significant adverse effects.

CONCLUSION

1 year cyclical pamidronate is effective and safe in improving bone mineralisation and reducing fracture incidence in osteogenesis imperfecta.

Encephalitis associated with motor polyneuropathy

We describe three patients with acute encephalitis and motor-dominant polyneuropathy. All three patients were in their middle age and presented with features of encephalopathy with flu like illness. Cerebrospinal fluid (CSF) studies showed lymphocytic pleocytosis with increased protein. Brain magnetic resonance imagings (MRIs) showed symmetric high signal intensities in bilateral mesial temporal lobes and bilateral thalami in all patients. All three patients became quadriplegic and areflexic within two hospital days (HDs) and electrophysiologic studies revealed motor polyneuropathy. Viral or atypical bacterial infection was suspected, but no causative agent could be found. One patient expired on the twentieth hospital day, and the other two patients showed no or little improvement. To our knowledge, this combination of acute encephalitis with motor polyneuropathy has not been reported.

Close correlation of p53 mutation to microvascular invasion in hepatocellular carcinoma

Mutation of p53 is a poor prognostic indicator of hepatocellular carcinoma (HCC). Although poor histologic differentiation of HCC has been associated with p53 mutations, the exact reasons for unfavorable clinical outcomes in patients with HCC remain to be clarified. In this study, we evaluate the association between p53 mutation and histopathologic features of HCCs, as well as tumor recurrences and survival. We examined 20 HCCs and surrounding liver tissues from patients who underwent surgical resection, and we performed direct sequencing of p53 gene. p53 mutations were found in 9 of 20 HCCs; none were found in the surrounding liver tissue. p53 mutations were frequent in large, multinodular, and poorly differentiated HCCs. Five of 9 with p53 mutation (in contrast, none of 11 with wild-type mutation) showed microvascular invasions. Hepatocellular carcinoma recurred in 6 of 9 with p53 mutation, in contrast to only 2 of 11 with wild-type mutation. The 1-year survival rate with p53 mutation was significantly lower than that with wild-type. In conclusion, it is suggested that p53 mutations tend to be commonly associated with microvascular invasions, which may result in micrometastasis, followed by frequent recurrences.

1,4-dioxane-fused 4-anilinoquinazoline as inhibitors of epidermal growth factor receptor kinase

The 4-anilinoquinazoline PD 153035 (1) is a potential antitumor agent which acts by inhibiting tyrosine kinase activity of epidermal growth factor receptor (EFGR) via competitive binding at the ATP site of enzyme. A series of cyclic analogues of PD 153035 bearing the 1,4-dioxane ring was prepared by reaction of 6-chloro derivative 5 with several aniline nucleophiles. These were evaluated for their ability to inhibit the EGFR kinase and the growth of primary human tumor cell cultures. All of the new 4-anilinoquinazolines exhibited less potency than PD 153035 against EGFR kinase. However, compounds 2b, 2c, 2e, 2g, and 2h showed higher inhibitory activities than PD 153035 against the growth of A431 tumor cell line. The compound 2b containing 3-chloroaniline ring was as potent as PD 153035 against EGFR kinase and showed about 5.4-fold better potency than PD153035 in the inhibition of growth of A431 cell line with good selectivity.

Outcome of renal transplantation in hepatitis B surface antigen-positive patients after introduction of lamivudine

BACKGROUND

In end-stage renal disease patients with hepatitis B surface antigen (HBsAg), the risk of hepatic dysfunction after immunosuppression represents a large barrier in renal transplantation. Lamivudine is a potent inhibitor of hepatitis B virus (HBV) replication. We retrospectively investigated the outcome of HBsAg-positive renal transplantation recipients after lamivudine had become available.

METHODS

From July 1994 to August 2000, seventeen HBsAg-positive patients (M:F=15:2) received renal allografts (13:4=living:cadaveric donors). Liver function tests at the time of transplantation were normal in all patients. Pre-transplant liver biopsies performed in 15 patients demonstrated minimal inflammatory histology, except in three patients showing pathological and clinical signs of active hepatitis. Lamivudine was started pre-operatively in these three subjects. Another seven patients were treated with lamivudine for post-operative hepatic dysfunction. The remaining seven patients did not develop hepatic dysfunction after transplantation.

RESULTS

Lamivudine was initially effective in decreasing serum HBV DNA titres, and in normalizing hepatic enzymes. Lamivudine was well tolerated without significant side effects for 35.5+/-8.9 months after initiation of treatment. HBV DNA became negative in nine patients but remained positive in one patient. Among the nine patients with initial negative conversion of HBV DNA, two developed transient positive conversion of HBV DNA and two demonstrated persistent positive conversion. Among the patients with normal liver histology in the pre-transplant period, 41.6% (5/12) developed liver pathology progression after immunosuppression. All 17 patients had functioning grafts, except for one patient who developed relapsed IgA nephropathy.

CONCLUSIONS

Our data showed relatively favourable outcomes in hepatitis B-positive renal transplant recipients receiving lamivudine treatment, even though two patients developed lamivudine resistance.

Effects and neuro-toxic mechanisms of 2, 2', 4, 4', 5, 5'-hexachlorobiphenyl and endosulfan in neuronal stem cells

Endocrine disrupters are exogenous compounds thought to mimic the action of estrogen or other hormones and influence endocrine activity in the body (Juberg, 2000). These chemicals have adverse effects not only in the reproductive system but also in the central nervous system during development and throughout life. Polychlorinated biphenyls (PCBs) are a class of environmentally persistent and widespread halogenated hydrocarbons. It has been reported that PCBs are potential neurotoxicants. Endosulfan is an organochlorine insecticide that is extensively used to control pests in vegetables, cotton, and fruits. To determine the effect of 2, 2', 4, 4', 5, 5',-hexachlorobiphenyl(2, 4, 5-HCB) and endosulfan on embryo nervous system, we isolated neural stem cells from rat brain at embryonic day 17. Isolated neural stem cells showed pluripotenty. Stem cells could differentiate into neurons and glia. Neurite formation in endosulfan and 2, 4, 5-HCB treated cells. And it appeared to be decreased as compared with that in untreated cells. In order to know the neuro-toxic mechanisms of 2, 4, 5-HCB and endosulfan in neuronal stem cells, we investigated mitogen-activated protein kinase activity (MAPK) and gap junctional intercellular communication (GJIC). Endosulfan decreased the MAPK activity in dose dependent manner. Endosulfan and 2, 4, 5-HCB inhibited GJIC compared to the untreated cell by scrape loading dye transfer (SL/DT). 2, 4, 5-HCB and endosulfan decreased the expression of connexin 43 in dose dependent manner. These results indicated that 2, 4, 5-HCB and endosulfan may inhibit differentiation and proliferation of neural stem cells and gap junctional intercellular communication which play a crucial role in the maintenance of cellular homeostasis.