A rapid method for simultaneous determination of 15 flavonoids in Epimedium using pressurized liquid extraction and ultra-performance liquid chromatography

Herba Epimedii (family Berberidaceae), Yinyanghuo in Chinese, is one of commonly used Chinese medicines. Flavonoids are considered as its active components. In this study, a rapid ultra-performance liquid chromatography (UPLC) method was developed for simultaneous determination of 15 flavonoids, including hexandraside E, kaempferol-3-O-rhamnoside, hexandraside F, epimedin A, epimedin B, epimedin C, icariin, epimedoside C, baohuoside II, caohuoside C, baohuoside VII, sagittatoside A, sagittatoside B, 2''-O-rhamnosyl icariside II and baohuoside I in different species of Epimedium. The analysis was performed on Waters Acquity UPLC system with an Acquity UPLC BEH C18 column (50 mm x 2.1mm I.D., 1.7 microm) and gradient elution of 50mM acetic acid aqueous solution and acetonitrile within 12 min. All calibration curves showed good linearity (R2>0.9997) within test ranges. The LOD and LOQ were lower than 0.13 and 0.52 ng on column, respectively. The R.S.D.s for intra- and inter-day of 15 analytes were less than 5.0% at three levels, and the recoveries were 95.0-103.7%. The validated method was successfully applied to quantitatively analyze 15 flavonoids in different species of Epimedium. The results showed there were great variations among the contents of investigated flavonoids. Hierarchical clustering analysis based on characteristics of 15 investigated compounds peaks in UPLC profiles showed that 37 samples were divided into 3 main clusters, which were in accordance with their flavonoids contents. The simulative mean chromatogram of the high content cluster was generated to compare the samples from different species and/or locations of Epimedium. Four flavonoids including epimedin A, B, C and icariin were selected as markers for quality control of the species of Epimedium used as Yinyanghuo.

Simultaneous determination of 15 flavonoids in Epimedium using pressurized liquid extraction and high-performance liquid chromatography

Herba Epimedii (family Berberidaceae), Yinyanghuo in Chinese, is one of the commonly used Chinese medicines. Flavonoids are considered as its active components. In this study, a reliable pressurized liquid extraction (PLE) and HPLC method was developed for simultaneous determination of 15 flavonoids, namely hexandraside E, kaempferol-3-O-rhamnoside, hexandraside F, epimedin A, epimedin B, epimedin C, icariin, epimedoside C, baohuoside II, caohuoside C, baohuoside VII, sagittatoside A, sagittatoside B, 2''-O-rhamnosyl icariside II and baohuoside I in different species of Epimedium. The analysis was performed by using a Zorbax SB-C18 analytical column (250 mm x 4.6 mm I.D., 5 microm) at gradient elution of water and acetonitrile with diode-array detection (270 nm). All calibration curves showed good linearity (r(2)>0.9997) within test ranges. The LOD and LOQ were lower than 1.31 ng and 2.62 ng on column, respectively. The RSD for intra- and inter-day of 15 analytes was less than 3.8% at three levels, and the recoveries were 90.5-106.8%. The validated method was successfully applied for the analysis of 15 flavonoids in different species of Epimedium which had great variation on the contents of investigated flavonoids. Hierarchical clustering analysis based on the characteristics of 15 investigated compound peaks in HPLC profiles showed that 26 samples were divided into three main clusters, which were in accordance with their flavonoid contents. Four flavonoids including epimedin A, B, C and icariin were optimized as markers for quality control of the species of Epimedium used as Yinyanghuo.

Qualitative and quantitative analyses of nucleosides and nucleobases in Ganoderma spp. by HPLC–DAD-MS

A high-performance liquid chromatography-diode array detector-mass spectrometry (HPLC-DAD-MS) analytical method was developed for detection of the nucleosides and nucleobases in two species of Lingzhi, the dried sporophore of Ganoderma lucidum and G. sinense. The method, combining advantages of both DAD and MS, was successfully used to qualitatively identify for six nucleosides namely, adenosine, cytidine, guanosine, inosine, thymidine, uridine and five nucleobases namely, adenine, guanine, hypoxanthine, thymine and uracil in Lingzhi samples. Quantitative analyses showed that uridine was the most abundant nucleoside in these Lingzhi samples and the contents of nine target analytes were found to be different in pileus and stipes of the fruiting bodies and among the different species of G. spp. The established method might apply as an alternative approach for the quality assessment of Lingzhi.

Quantitative determination of eight components in rhizome (Jianghuang) and tuberous root (Yujin) of Curcuma longa using pressurized liquid extraction and gas chromatography–mass spectrometry

Curcuma longa (Zingiberaceae) is a native plant of southern Asia and is cultivated extensively throughout the warmer parts of the world. Jianghuang and Yujin are rhizome and tuberous root of C. longa, respectively, which were traditionally used as two Chinese medicines. In this paper, pressurized liquid extraction (PLE) and gas chromatography-mass spectrometry (GC-MS) were developed for quantitative determination/estimation of eight characteristic compounds including beta-caryophyllene, ar-curcumene, zingiberene, beta-bisabolene, beta-sesquiphellandrenendrene, ar-turmerone, alpha-turmerone and beta-turmerone in Jianghuang and Yujin. A HP-5MS capillary column (30 m x 0.25 mm i.d.) coated with 0.25 microm film 5% phenyl methyl siloxane was used for separation and selected ion monitoring (SIM) method was used for quantitation. Hierarchical cluster analysis based on characteristics of eight identified peaks in GC-MS profiles showed that 10 samples were divided into two main clusters, Jianghuang and Yujin, respectively. Four components such as ar-curcumene, ar-turmerone, alpha-turmerone and beta-turmerone were optimized as markers for quality control of rhizome (Jianghuang) and tuberous root (Yujin), which are two traditional Chinese medicines, from Curcuma longa.

Optimization of pressurized liquid extraction of five major flavanoids from Lysimachia clethroide

As an alternative of traditional extraction method, pressurized liquid extraction (PLE) was applied for five flavanoids extraction from Lysimachia clethroide. The operational parameters of PLE, such as extraction solvent, temperature, pressure, static extraction time, flush volume and cycles were optimized by univariate approach coupled with central composite design (CCD) in order to obtain the highest extraction efficiency. The optimized result employed 50% acetonitrile aqueous as extraction solvent, 100 degrees C of extraction temperature, 1500 psi of extraction pressure, 25 min of static time, 70% flush volume, and only one cycle to extract the target compounds completely. Finally, the contents of five major flavanoids in L. clethroides from different sources were determined simultaneously by the combination of the presented PLE and HPLC method.

Optimization of GC–MS conditions based on resolution and stability of analytes for simultaneous determination of nine sesquiterpenoids in three species of Curcuma rhizomes

GC-MS is a powerful tool for analysis of volatile oil, and resolutions of analytes were exclusively used as marker for optimization of the conditions. However, volatile oil usually contains heat labile components which may degrade and result in wrong results during GC analysis. In present study, based on both resolutions and stabilities of 11 sesquiterpenoids, GC-MS conditions were optimized for simultaneously quantitative determination of nine compounds including beta-elemene, curzerene, curcumol, isocurcumenol, germacrone, curdione, curcumenol, neocurdione and curcumenone in Ezhu. However, the other two compounds, i.e. furanodienone and furanodiene, were still thermal sensitive and not available for GC analysis. The results showed that both resolutions and stabilities of analytes should be considered for optimization of GC conditions because the properties of most components in volatile oil are unknown. Under optimum conditions, a capillary column (30 m x 0.25 mm i.d.) coated with 0.25 microm film 5% phenyl methyl siloxane was used for separation. Pulsed splitless inlet with temperature of 190 degrees C was selected for sample injection (0.2 microl). The calibration curves of nine sesquiterpenoids showed good linearity (r2>0.9989) within test ranges. The optimized method showed good repeatability for quantification of these nine components in Ezhu with intra- and inter-day variations of less than 1.42% and 2.79%, respectively. The validated method was successfully applied to quantify 9 sesquiterpenoids in 18 samples of 3 species of Curcuma used as Ezhu.

Simultaneous determination of 11 characteristic components in three species of Curcuma rhizomes using pressurized liquid extraction and high-performance liquid chromatography

A high-performance liquid chromatography coupled with diode array detection (HPLC-DAD) and pressurized liquid extraction was developed for simultaneous quantitative determination of 11 characteristic compounds, including curcumenone, curcumenol, neocurdione, curdione, isocurcumenol, furanodienone, curcumol, germacrone, curzerene, furanodiene and beta-elemene, in rhizomes of three species of Curcuma. The analysis was performed on an ODS C18 column. The mobile phase consisted of (A) water and (B) acetonitrile using a gradient elution. The peaks were monitored at both 214 nm and 256 nm. All calibration curves showed good linearity (r2 > 0.9996) within test ranges. This method showed good repeatability for the quantification of these eleven components in three species Curcuma rhizomes with intra- and inter-day variations of less than 1.57% and 1.98%, respectively. The validated method was successfully applied to quantify 11 investigated components in eighteen samples of three species of Curcuma, which is helpful to control their quality.

A case of minimal-change nephrotic syndrome in pediatric lupus erythematosus: just a coincidence?

A 14-year old girl with lupus erythematosus (LE) who initially showed as discoid lupus and followed with nephrotic syndrome one year later. Concomitant piroxicam and indomethacin were prescribed for her arthritis, which preceded two months before the onset of nephrotic syndrome. Histology from renal biopsy showed minimal-change nephrotic syndrome (MCNS). After continuous treatment for six months, nephrotic syndrome resolved completely and no signs of relapse were noted over 14 years of follow-up. For the children, it is rare to have both LE and MCNS simultaneously; sequela of nonsteroidal anti-inflammatory drugs also seldom results in nephrotic syndrome. Though their relationship is still not defined, the possibility of LE combined with MCNS must be differentiated in patients with lupus and severe proteinuria.

Endogenous insulin signaling protects cultured neurons from oxygen-glucose deprivation-induced cell death

Curiosity surrounding the physiological relevance of neural insulin signaling has gradually developed since the discovery that nervous tissue contains both the hormone and its receptor. Similar to other receptor tyrosine kinases, ligand interaction with the insulin receptor (IR) activates a variety of intracellular signaling pathways, particularly those relevant to cellular survival. Consequently, one explanation for the presence of the insulin pathway in the brain may involve participation in the response to neuronal injury. To investigate this possibility, the present study began by examining the effect of oxygen-glucose deprivation (OGD), a well-characterized in vitro model of ischemia, on ligand-binding, surface expression, and function of the IR in cultured rat neurons that were prepared under serum-free conditions. Reduced insulin-binding was observed following OGD, although surface expression of the receptor was not altered. However, OGD did significantly decrease the ability of insulin to stimulate phosphorylation of the transmembrane IR beta-subunit, without affecting protein expression of this subunit. Subsequent experiments focused on the manner in which pharmacologically manipulating IR function affected neuronal viability after OGD. Application of the IR sensitizer metformin moderately improved neuronal viability, while the specific IR tyrosine kinase inhibitor tyrphostin A47 was able to dramatically decrease viability; both compounds acted without affecting IR surface expression. Our study suggests that not only does the IR appear to play an important role in neuronal survival, but also that neurons may actively maintain IRs on the cell surface to compensate for the OGD-induced decrease in the ability of insulin to phosphorylate its receptor.

GABAA receptor-associated phosphoinositide 3-kinase is required for insulin-induced recruitment of postsynaptic GABAA receptors

Type A gamma-aminobutyric acid (GABAA) receptors mediate most of the fast inhibitory synaptic transmission within the vertebrate brain. The regulation of this inhibition is vital in modulating neural activity. One regulator of GABAA receptor function is insulin, which can serve to enhance GABAA receptor-mediated miniature inhibitory postsynaptic currents, via an increase in the number of receptors at the plasma membrane. We set out to investigate the molecular mechanisms involved in the insulin-induced potentiation of GABAA receptor-mediated responses, by examining the role of phosphoinositide 3-kinase (PI3-K), a key mediator of the insulin response within the brain. We found that PI3-K associates with the GABAA receptor, and this interaction is increased following insulin treatment. Additionally, the beta2 subunit of the GABAA receptor appears to mediate the insulin-stimulated association with the N-terminal SH2 domain of the p85 subunit of PI3-K. Our results imply a mechanism whereby insulin can regulate changes in synaptic transmission through its downstream actions on the GABAA receptor.

Chemical characteristics for different parts of Panax notoginseng using pressurized liquid extraction and HPLC-ELSD

The chemical characteristics for different parts of Panax notoginseng, including root, fibre root, rhizome, stem, leaf, flower and seed, were determined using high performance liquid chromatography-evaporative light scattering detection (HPLC-ELSD) and pressurized liquid extraction (PLE). Eight major saponins, namely notoginsenoside R1, ginsenosides Rg1, Re, Rb1, Rc, Rb2, Rb3 and Rd were also quantitatively compared among the different parts of P. notoginseng. The chromatograms showed that there was significant difference between underground (root, fibre root, rhizome) and aerial (leaf and flower) parts from P. notoginseng, though the similarities of entire chromatographic patterns among tested samples from underground (0.965+/-0.029, n=12) and aerial parts (0.987+/-0.014, n=5) were similar, respectively. Especially, no saponin was detected in the seed of P. notoginseng. Hierarchical clustering analysis based on eight investigated saponins or the ratios of contents for ginsenoside Rg1/Rb1 and ginsenoside Rb3/Rb1 showed that the samples from different parts of P. notoginseng were divided into three main clusters. One cluster was underground parts, which contained rich protopanaxatriol and protopanaxadiol types saponins. The leaf and flower were in the same cluster, which contained protopanaxadiol type saponins only. Especially, ginsenoside Rc, Rb2 and Rb3, rare in the underground parts, were rich in aerial parts of P. notoginseng. The stem of P. notoginseng was another cluster. Based on the cluster analysis, the chemical characteristics for different parts of P. notoginseng were revealed. They are composite cluster (underground parts), protopanaxadiol cluster (aerial parts) and interim (stem) cluster, which was the one between the two typical clusters, respectively. The result shows that chemical characteristics of underground parts and aerial parts from P. notoginseng are obviously different, which is helpful for pharmacological evaluation and quality control of P. notoginseng.

Treatment outcome of Singapore residents with pulmonary tuberculosis in the first year after introduction of a computerised treatment surveillance module

INTRODUCTION

A key intervention of the Singapore Tuberculosis Elimination Programme (STEP) was the introduction in 2001 of a computerised treatment surveillance module (TSM) for the real-time monitoring of the treatment progress of the country's notified tuberculosis (TB) cases until a final outcome. We report the treatment outcome as at December 31, 2002 for the cohort of Singapore residents with new and relapsed pulmonary TB in whom treatment was commenced in 2001.

METHODS

Each TB notification will activate the TSM, which requires a return on the patient's treatment progress, treatment delivery mode and the treating physician's management decision at each clinic visit to the STEP Registry until an outcome is reached.

RESULTS

There were 1,354 Singapore residents with new or relapsed pulmonary TB who started treatment in 2001. Of these, 620 (45.8 percent) underwent directly-observed therapy (DOT) at their nearest polyclinic. As at December 31, 2002 , 79 percent of patients completed treatment, nine percent died (two percent from TB), nine percent interrupted treatment (they were either lost to follow-up or refused treatment), 1.8 percent were still on treatment, 0.6 percent left the country, and 0.5 percent had permanent cessation of treatment due to drug reactions. Factors associated with treatment completion were Chinese ethnicity (odds-ratio [OR] 1.5, 95 percent confidence interval [Cl] 1.1-2, p-value is 0.02), age younger than 65 years (OR 1.8, 95 percent Cl 1.3-3.0, p-value is 0.003) and the use of DOT (OR 3.1, 95 percent Cl 2.3-4.1, p-value is less than 0.05).

CONCLUSION

The findings from the TSM's first year provide a baseline for future programme evaluation.

Hypoglycemic activity of polysaccharide, with antioxidation, isolated from cultured Cordyceps mycelia

Cordyceps sinensis, a well-known traditional Chinese medicine, possesses anti-tumor, immunostimulant and antioxidant activities; however, the identities of active components have not been determined. In our previous study using antioxidant activity-guided fractionation [Li et al., 2003. A polysaccharide isolated from Cordyceps sinensis, a traditional Chinese medicine, protects PC12 cells against hydrogen peroxide-induced injury. Life Sci. 73, 2503-2513], a polysaccharide of molecular weight approximately 210kDa was isolated from cultured Cordyceps mycelia by ion-exchange and sizing chromatography. The isolated polysaccharide, named CSP-1, which has strong anti-oxidation activity, contains glucose, mannose and galactose in the ratio of 1:0.6:0.75. In the present study, we demonstrated the hypoglycemic effect of CSP-1 on normal and alloxan-diabetic mice and streptozotocin (STZ)-diabetic rats. The basal glucose level did not differ significantly among the normal mice. CSP-1 (at 200 and 400mg/kg body wt./day for 7 days, p.o.), however, significantly reduced the blood glucose level by 12.0+/-3.2% and 22.5+/-4.7% in normal mice, respectively (p<0.05). When administered at a dose of higher than 200mg/kg body wt. daily for 7 days, CSP-1 produced a significant drop in blood glucose level in both STZ-induced diabetic rats and alloxan-induced diabetic mice. The serum insulin levels in diabetic animals were also increased by administration of CSP-1 (p<0.05). CSP-1 with hypoglycemic properties increased circulating insulin level in diabetic animals, which suggests that CSP-1 may stimulate pancreatic release of insulin and/or reduce insulin metabolism.

Optimization of pressurized liquid extraction for Z-ligustilide, Z-butylidenephthalide and ferulic acid in Angelica sinensis

Pressurized liquid extraction, one of the most promising and recent sample preparation techniques, offers the advantages of reducing solvent consumption and allowing for automated sample handling. It is being exploited in diverse areas because of its distinct advantages. However, because the extraction is performed at elevated temperatures using PLE, thermal degradation could be a concern. Z-ligustilide, one of the biologically active components in Angelica sinensis, is an unstable compound, which decomposes rapidly at high temperature. In this study, we carried out a comparative study to evaluate PLE as a possible alternative to current extraction methods like Soxhlet and sonication for simultaneous extraction of Z-ligustilide, Z-butylidenephthalide and ferulic acid in A. sinensis. The operating parameters for PLE including extraction solvent, particle size, pressure, temperature, static extraction time, flush volume and numbers of extraction were optimized by using univariate approach coupled with central composite design (CCD) in order to obtain the highest extraction efficiency. Determination of Z-ligustilide, Z-butylidenephthalide and ferulic acid were carried out by means of high performance liquid chromatography with diode-array detector. The results showed that PLE was a simple, high efficient and automated method with lower solvent consumption compared to conventional extraction methods such as Soxhlet and sonication. PLE could be used for simultaneous extraction of Z-ligustilide, Z-butylidenephthalide and ferulic acid in A. sinensis.

Simultaneous determination of saponins and fatty acids in Ziziphus jujuba (Suanzaoren) by high performance liquid chromatography-evaporative light scattering detection and pressurized liquid extraction

The seed of Ziziphus jujube Mill. var. spinosa (Bunge) Hu ex H. F. Chou, Suanzaoren in Chinese, is one of commonly used Chinese medicines. Saponins and fatty oil contains several fatty acids in Suanzaoren are responsible for its therapeutic activities. In this study, a new HPLC coupled with evaporative light scattering detection (ELSD) and pressurized liquid extraction (PLE) method was developed for the simultaneous quantitative determination of 11 major components of 2 saponins and 9 fatty acids, namely jujuboside A, jujuboside B, lauric acid, myristic acid, palmitic acid, palmitoleic acid, stearic acid, oleic acid, linoleic acid, arachidic acid and docosanoic acid in Suanzaoren. Simultaneous separation of these eleven compounds was achieved on a C18 analytical column. The mobile phase consisted of (A) 0.1% aqueous acetic acid and (B) methanol with 0.1% acetic acid using a gradient elution. The drift tube temperature of ELSD was set at 75 degrees C, and nitrogen flow-rate was 1.8l/min. All calibration curves showed good linearity (r(2)>0.9955) within test ranges. This method showed good reproducibility for the quantification of these eleven components in Suanzaoren with intra- and inter-day variations of less than 3.41 and 4.37%, respectively. The validated method was successfully applied to quantify 11 investigated components in nine commercial samples of Suanzaoren.

Pressurized liquid extraction followed by high-performance liquid chromatography for determination of seven active compounds in Cortex Dictamni

A new method based on pressurized liquid extraction (PLE) followed by a sensitive and specific HPLC-DAD analysis is developed for determination of seven compounds in Cortex Dictamni. The operational parameters of PLE, such as extraction solvent, extraction temperature, extraction pressure, static extraction time, flush volume and extraction cycles were optimized, using the extraction efficiencies of dictamnine, obacunone and fraxinellone as targets. The optimized procedure employed MeOH as extraction solvent, 150 degrees C of extraction temperature, 1,500 psi extraction pressure, 5 min of static extraction time, 60% flush volume and the extraction recoveries of the three compounds were nearly to 100% for only one cycle. The following HPLC analysis was performed on a reversed-phase C(18) column with methanol-water as mobile phase in gradient manner, detected at 236 and 218 nm. The limits of detection (LOD) and limits of quantification (LOQ) of the seven compounds were in the range of 0.4-15.6 ng and 1.2-38.8 ng. This assay can be readily utilized as a quality control method for Cortex Dictamni and other related medicinal plants.

A rapid HPLC–ESI-MS/MS for qualitative and quantitative analysis of saponins in “XUESETONG” injection

'XUESETONG' injection, one of the most widely used proprietary medicines in traditional Chinese medicine, consists of total saponins made from Panax notoginseng, which is a highly valued and important Chinese medicinal herb. It is used to treat cardiovascular diseases. In order to control the quality of XUESETONG injection, a rapid HPLC-ESI-MS/MS method was developed for qualitative and quantitative determination of the saponins. The analyses were performed on SB-C18 column using gradient elution in 25 min. Full scan and time programmed selected reaction monitoring (SRM) were used for qualitative and quantitative analysis of saponins, respectively. Twenty-seven saponins were identified and nine of them including notoginsenoside R1, ginsenoside Rb1, Rb2, Rb3, Rc, Rd, Re, Rf and Rg1 were quantified. Ten XUESETONG injections were analyzed and compared. The results showed that there is a great variation among different samples. In conclusion, the developed method is rapid, accurate and sensitive for qualitative and quantitative analysis of saponins in XUESETONG injection. Moreover, it also can be used for the quality control of P. notoginseng raw material and its preparations.

Optimization for quantitative determination of four flavonoids in Epimedium by capillary zone electrophoresis coupled with diode array detection using central composite design

Herba Epimedii (family Berberidaceae), Ying-Yang-Huo in Chinese, is a famous Chinese herbal medicine. Flavonoids are thought to be the major active components in it. A capillary zone electrophoresis (CZE) separation were developed for simultaneous determination of four flavonoids including icariin, epimedin A, epimedin B and epimedin C in Epimedium. The effects of the experimental variables on CZE had been optimized by using central composite design (CCD). The best separation of four flavonoids could be obtained using 50 mM borate buffer (pH 10.0) containing 22% acetontrile as modifier, while separation voltage was 15 kV and temperature was at 25 degrees C. The method developed is accurate, simple and reproducible, which could be used for quality control of Epimedium and its medical preparations.

Simultaneous determination of nine saponins from Panax notoginseng using HPLC and pressurized liquid extraction

A HPLC and pressurized liquid extraction (PLE) method was developed for simultaneous determination of nine saponins, including notoginsenoside R1, ginsenoside Rg1, Re, Rf, Rb1, Rc, Rb2, Rb3 and Rd in Panax notoginseng. The analysis was performed on C18 column with water-acetonitrile gradient elution and the investigated saponins were authenticated by comparing retention time and mass spectra with their reference compounds. Several methods including PLE, ultrasonication, soxhlet extraction and immersion were used for sample preparation and their extraction efficiency was compared. The results showed that PLE has the highest extraction efficiency and repeatability, which would be valuable on standardization of sample preparation for quality control of Chinese medicines. The developed HPLC and PLE is an effective approach for simultaneously quantitative determination of sapoinins in P. notoginseng, which could be used for quality control of P. notoginseng and its preparations.

Contact screening and latent TB infection treatment in Singapore correctional facilities

SETTING

Singapore, a city-state with a tuberculosis (TB) incidence rate of 47 per 100000 population in 2000.

OBJECTIVES

1) To report our experience with contact investigation and latent TB infection (LTBI) treatment in high-risk contacts with unknown human immunodeficiency virus (HIV) status in correctional facilities (CFs) (prisons/drug rehabilitation centres); and 2) to compare the yield of contact screening in this setting with that in the community (household/family) setting.

METHODS

The tuberculin skin test (TST) readings of 704 CF contacts screened from 1999 to 2001 were compared with those of 2729 household/family contacts who underwent screening in 2000.

RESULTS

Respectively eight (1.1%) and 20 (0.7%) active TB cases were detected among the CF and community contacts. A significantly higher proportion of CF contacts had first (non-conversion) TST readings > or =15 mm (39% vs. 22%, OR 2.3; 95%CI 1.9-2.7; P < 0.001), and 10-14 mm (26% vs. 18%, OR 1.6; 95%CI 1.3-2.0; P < 0.001) and TST conversion (43% vs. 20%, OR 2.9; 95%CI 1.7-4.9; P < 0.001). LTBI treatment was started in 65% of the CF contacts screened; 87% completed treatment.

CONCLUSION

We found a high LTBI rate among CF contacts, presenting an opportunity for intervention.

GC-MS fingerprint of Pogostemon cablin in China

Pogostemon cablin, originating in Malaysia and India, is cultivated in southern China including Guangdong and Hainan Province, which was called GuangHuoXiang to differentiate it from the HuoXiang of the north, the species Agastache rugosa, that it resembles. Essential oil of P. cablin mainly contributes to the pharmacological activities and the therapeutic properties of the essential oils are directly correlated with their qualitative and quantitative composition. For controlling the quality, standard fingerprint of P. cablin collected from different regions was developed by using GC-MS. Nine compounds including beta-patchoulene, caryophyllene, alpha-guaiene, seychellene, beta-guaiene, delta-guaiene, spathulenol, patchouli alcohol and pogostone were identified among 10 main peaks in P. cablin. Hierarchical clustering analysis based on characteristics of 10 investigated peaks in GC profiles showed that 18 samples were divided into three main clusters, patchouliol-type, pogostone-type and an interim-type, which was the one between the two chemotypes. The simulative mean chromatogram for the three types P. cablin was generated using the Computer Aided Similarity Evaluation System. The fingerprint can help to distinguish the substitute or adulterant, and further assess the differences of P. cablin grown in various areas of China.

Identification and quantitation of eleven sesquiterpenes in three species of Curcuma rhizomes by pressurized liquid extraction and gas chromatography–mass spectrometry

In this paper, GC-MS and pressurized liquid extraction (PLE) was developed for identification and quantitative determination/estimation 11 sesquiterpenes including germacrene D, curzerene, gamma-elemene, furanodienone, curcumol, isocurcumenol, furanodiene, germacrone, curdione, curcumenol and neocurdione in Ezhu which are derived from three species of Curcuma, i.e., Curcuma phaeocaulis, Curcuma wenyujin and Curcuma kwangsiensis by using an analogue as standard. The results showed the methodology could quantitatively compare the quality of three species of Curcuma. The contents of investigated sesquiterpenes in three species of Curcuma were high variant. Hierarchical clustering analysis based on characteristics of 11 identified peaks in GC profiles showed that 18 samples were divided into two main clusters, C. phaeocaulis and C. wenyujin, respectively. C. kwangsiensis showed the characters closed to C. phaeocaulis or C. wenyujin based on its location. Five components such as furanodienone, germacrone, curdione, curcumenol and neocurdione were optimized as markers for quality control of Ezhu.

Simultaneous determination of ergosterol, nucleosides and their bases from natural and cultured Cordyceps by pressurised liquid extraction and high-performance liquid chromatography

A simple method is described for the simultaneous determination of ergosterol, nucleosides and their bases in Cordyceps. The samples were extracted by using pressurised liquid extraction (PLE). The effects of experimental variables, such as solvent, temperature, static extraction time and cycles, on PLE efficiency have been studied. The results showed a strong influence of the solvent and temperature on extraction efficiency of PLE. The determination was achieved by high-performance liquid chromatography (HPLC) using a Zorbax NH2 analytical column (250 x 4.6 mm i.d., 5 microm) with diode-array detector (DAD). The automated preparation of the sample permits a very fast analysis which is an important goal for routine purpose.

Simultaneous determination of six main nucleosides and bases in natural and cultured Cordyceps by capillary electrophoresis

A simple method is described for simultaneous determination of six main nucleosides and bases including adenine, uracil, adenosine, guanosine, uridine and inosine in Cordyceps by capillary electrophoresis (CE). Chemometric optimization based on central composite design was employed to find the optimum resolution. The optimum factor space was defined by three parameters: buffer concentration, pH and concentration of acetonitrile as organic modifier. Resolution (Rs) was employed to evaluate the response function. A running buffer composed of 500 mM boric acid, adjusted pH to 8.6 with sodium hydroxide and 12.2% acetonitrile as modifier was found to be the most appropriate for the separation. The contents of the six components were determined by using adenosine monophosphate as an internal standard. Furthermore, hierarchical clustering analysis based on characteristics of 32 peaks in CE profiles from the tested 12 samples showed that natural and cultured Cordyceps were in different clusters. Adenosine and inosine were extracted as markers for discrimination of natural Cordyceps. The result of clustering based on the two peaks characteristics was in excellent agreement with that based on 32 peaks'. Thus, adenosine and inosine could be used as markers for quality control of natural and cultured Cordyceps.

Treatment of latent TB infection for close contacts as a complementary TB control strategy in Singapore

OBJECTIVE

To describe our initial experience with treatment of latent tuberculosis infection (LTBI) for close contacts of infectious TB cases in Singapore, an intermediate TB burden country with mass BCG (re)vaccination since the 1950s.

METHODS

Screening of 5699 contacts of 1374 index cases notified in 1998 was carried out at the TB Control Unit.

RESULTS

Seventy-five per cent (4239) completed tuberculin skin testing (TST). Fifty-three cases of TB disease were detected (0.9% yield). Twenty-one per cent (895/4239) of the TST-screened contacts were started on LTBI treatment, comprising 92% (810/883) of contacts with TST > or = 15 mm, 5% (64/1195) of those with TST 10-14 mm and 1% (21/2161) of those with TST < 10 mm. The regimen utilized was isoniazid for 6 months in adults and 9 months in children. Eighty-one per cent completed treatment. The incidence of isoniazid-induced hepatitis was 0.45%. Over the ensuing 4 years, one case of active TB was reported among those treated for LTBI, and 10 cases (five without TST readings) were notified among contacts who did not receive treatment.

CONCLUSIONS

Where good case-finding and treatment of TB disease exist, and where resources permit, LTBI treatment for close contacts is feasible as a complementary TB control strategy in an intermediate TB burden country with a BCG-vaccinated population.

Species-specific PCR primers for Pythium developed from ribosomal ITS1 region

AIMS

To develop a specific method for distinguishing and detecting Pythium species.

METHODS AND RESULTS

Twenty PCR primers were designed from the sequences of the rDNA internal transcribed spacer 1 (ITS1) region from 34 Pythium species. The specificity of these forward primers paired with ITS2 or ITS4 and reverse universal primers was tested. Five species-specific primers were obtained, other primers showed different specificity to Pythium species. The specific amplifications enabled nine Pythium species to be differentiated. Specific detection of Pythium aphanidermatum from infested plants and P. dimorphum from soil was demonstrated.

CONCLUSIONS

A method for identifying nine Pythium species using specific PCR amplification was achieved.

SIGNIFICANCE AND IMPACT OF THE STUDY

Because of its rapidness and ease, the results of PCR amplified with different primers can be a powerful method for identifying Pythium species and detecting or monitoring the target fungus directly from plant material, soil and water samples.

Antinociceptive effect of calcitonin gene-related peptide in the central nucleus of amygdala: activating opioid receptors through amygdala-periaqueductal gray pathway

The central nucleus of amygdala (CeA) plays an important role in pain regulation. Calcitonin gene-related peptide (CGRP)-like immunoreactive fibers and CGRP receptors are distributed densely in CeA. The present study was performed to elucidate the role of CGRP in nociceptive regulation in the CeA of rats. Intra-CeA injection of CGRP induced dose-dependent increases in the hind-paw withdrawal latency tested by hotplate test and Randall Selitto Test, indicating an antinociceptive effect of CGRP in CeA. Furthermore, the antinociceptive effect of CGRP was blocked by intra-CeA administration of the CGRP receptor antagonist CGRP8-37, suggesting that CGRP receptor1 is involved in the CGRP-induced antinociception. The CGRP-induced antinociception was attenuated by s.c. injection of the opioid antagonist naloxone, suggesting an involvement of endogenous opioid systems in CGRP-induced antinociception. Moreover, it was demonstrated that opioid receptors in the periaqueductal gray, but not in CeA, contributed to the CGRP-induced antinociception, indicating the importance of the pathway between CeA and the periaqueductal gray in CGRP-induced antinociception. Combining retrograde fluorescent tracing with immunohistochemistry, we found that met-enkephalinergic neurons were innervated by CGRP-containing terminals in CeA. Furthermore, most neurons in the CeA retrogradely traced from the periaqueductal gray were contacted by CGRP-containing terminals and some of them were surrounded by characteristic basket-like structures formed by the terminals, suggesting that CGRP innervates the neurons which project from CeA to the periaqueductal gray. The results indicate that CGRP activates the met-enkephalinergic neurons, which project from CeA to the periaqueductal gray, producing antinociceptive effect in rats.

Survival among Chinese women with lung cancer in Singapore: a comparison by stage, histology and smoking status

Lung cancer generally carries a poor prognosis and the determinants of survival have been of interest. However, survival estimates in Asian populations are scarce. This study describes survival rates and their determinants in Singapore Chinese women, a primarily non-smoking population. Three hundred and twenty-six Chinese women, diagnosed with primary lung carcinoma in three major hospitals in Singapore between April 1996 and December 1998, were followed up till 31 December 2000. The Kaplan-Meier method was used for survival analysis. Two hundred and eighty (85.7%) died from the disease during follow-up. The median survival time was 0.7 years and the three-year survival was 15.8%. These survival rates are similar to those of Western populations, and they provide a basis for examining trends over time. Age at diagnosis was an independent prognostic factor [adjusted hazard ratio (relative risk) 1.4, 95% confidence intervals (CI) 1.1-1.9 for women above 65 years relative to younger women]. Most (70.5%) tumours were stage III/IV at diagnosis. Three-year survival ranged from 72% among patients with stage I tumours to 7% for stage IV tumours. Overall, there was no survival difference among different histological types in all stages combined. When limited to stages I and II cancers, adenocarcinomas were associated with a better outcome relative to other histological subtypes combined (adjusted relative risk 0.4, 95% CI 0.1-1.0). Smoking was an independent risk factor (adjusted relative risk 1.3, 95% CI 1.0-1.8). Nevertheless, non-smokers comprised 57.4% of this series, highlighting the importance of increased awareness among health professionals and the public that lung cancer is not only a disease of smokers. The high proportion of late-stage tumours in this study and the impact of disease stage on outcome underline the importance of early detection in improving survival of lung cancer.

Performance of the rapidly extracted auditory evoked potentials index to detect the recovery and loss of wakefulness in anesthetized and paralyzed patients

BACKGROUND

The rapidly extracted auditory evoked potentials index (A-lineTM ARX Index or AAI) has been proposed as a method to measure the depth of anesthesia. A prospective study was designed to assess the performance of AAI to detect the recovery and loss of wakefulness in anesthetized and paralyzed patients.

METHODS

Fourteen adult patients undergoing elective surgery were anesthetized with propofol 1.5 mg kg-1, vecuronium 0.1 mg kg-1 and further propofol 1.0 mg kg-1. Wakefulness was measured by the ability of the patient to respond to command using the isolated forearm technique (IFT). After the patient responded, propofol was infused at 10 mg kg-1. h-1 until wakefulness (responsiveness) was lost. The AAI was recorded continuously throughout the study and analyzed off-line.

RESULTS

The AAI showed a significant difference between the values registered during, 30 s before and 30 s after the recovery, and also between 30 s before and 30 s after the loss of wakefulness. The prediction probability (Pk) values for AAI were 0.786 and 0.864 during the transitions from unresponsiveness to responsiveness and from responsiveness to unresponsiveness. The area under the receiver operating characteristic curve for the responsive and unresponsive values was 0.926 (SE 0.002, 95% CI 0.922-0.931), and the AAI values of approximately 5%, 50% and 95% predicted probability of wakefulness were 19, 29 and 39, respectively.

CONCLUSION

The AAI may be a good predictor of recovery and loss of wakefulness for anesthetized and paralyzed patients.

White spot syndrome virus (WSSV) infects specific hemocytes of the shrimp Penaeus merguiensis

White spot syndrome virus (WSSV) was specifically detected by PCR in Penaeus merguiensis hemocytes, hemolymph and plasma. This suggested a close association between the shrimp hemolymph and the virus. Three types of hemocyte from shrimp were isolated using flow cytometry. Dynamic changes of the hemocyte subpopulations in P. merguiensis at different times after infection were observed, indicating that the WSSV infection selectively affected specific subpopulations. Immunofluorescence assay (IFA) and a Wright-Giemsa double staining study of hemocyte types further confirmed the cellular localization of the virus in the infected hemocytes. Electron microscopy revealed virus particles in both vacuoles and the nucleus of the semigranular cells (SGC), as well as in the vacuoles of the granular cells (GC). However, no virus could be detected in the hyaline cells (HC). Our results suggest that the virus infects 2 types of shrimp hemocytes--GCs and SGCs. The SGC type contains higher virus loads and exhibits faster infection rates, and is apparently more susceptible to WSSV infection.

Hepatotoxicity of tuberculosis chemotherapy under general programme conditions in Singapore

SETTING

The Singapore Tuberculosis (TB) Control Unit, a high volume national referral centre.

OBJECTIVES

To determine the incidence, clinical course and outcome of TB drug-induced hepatitis (DH) and the risk factors associated with DH under general programme conditions.

DESIGN

A retrospective review of adult patients started on TB treatment in 1998.

RESULTS

There were 55 cases of DH in the cohort of 1036 patients treated in 1998. The median time to diagnosis of DH was 38 days. Factors significantly associated with DH were abnormal baseline transaminases/ bilirubin (OR 2.1, 95%CI 1.1-4.3, P = 0.02), age >60 years (OR 1.97, 95%CI 1.14-3.34, P = 0.01) and female sex (OR 1.9, 95%CI 1.07-3.4, P = 0.02). Ethnicity, self-reported alcohol consumption and body weight were not associated with development of DH. All three patients with fatal DH had received pyrazinamide-containing regimens. Treatment was re-introduced in 48 patients and successfully completed in 45 patients. The median time to reinstitution of TB treatment was 23 days.

CONCLUSION

The incidence of TB drug-induced hepatitis was 5.3%. Age >60 years, abnormal baseline transaminase/bilirubin levels and female sex were risk factors associated with the development of TB drug-induced hepatitis.

Changes in the rapidly extracted auditory evoked potentials index and the bispectral index during sedation induced by propofol or midazolam under epidural block

BACKGROUND

The bispectral index (BIS) and the rapidly extracted auditory evoked potentials index (A-line ARX Index or AAI) have been proposed as methods to measure the depth of sedation. A prospective study was designed to assess the performance of both these methods for measuring the depth of sedation induced by propofol or midazolam under epidural block.

METHODS

Thirty-two ASA I and II adult patients undergoing elective gynaecological surgery under low-thoracolumbar epidural block were studied. Eighteen patients received propofol (Group P: 20 mg bolus every 3 min) and 14 received midazolam (Group M: 0.5 mg bolus every 5 min) until an observer's assessment of alertness/sedation (OAA/S) scale score of 1 was achieved. AAI and BIS were monitored for different OAA/S scores.

RESULTS

AAI and BIS decreased and increased following the changes on the patients' OAA/S scores and correlated with sedation significantly. During the onset phase, the coefficients of Spearman's rank correlation for AAI and BIS were respectively 0.958 and 0.898 (P < 0.001) for Group P, and 0.973 and 0.945 (P < 0.001) for Group M. During the recovery phase in Group P, the coefficients were respectively 0.946 and 0.702 (P < 0.001). Linear regression analysis showed that both AAI and BIS were linearly related to the OAA/S scores. The coefficients of Spearman's rank correlation and linear regression for AAI were all greater than those for BIS (P < 0.05).

CONCLUSIONS

Both AAI and BIS correlated well with the depth of sedation induced by propofol or midazolam under epidural block. AAI may be more valuable when monitoring depth of sedation.

An assessment of the role of exhaled carbon monoxide in acute asthmatic exacerbations in hospitalised patients

Exhaled carbon monoxide is a useful marker of airway inflammation in untreated asthma. Whether exhaled CO is clinically useful in steroid treated patients in a hospital setting is uncertain. We therefore studied exhaled CO as a marker of asthma severity in clinical practice. Non-smoking "acute" asthmatics (hospitalised; n=33), "stable" asthmatics (n=35), and healthy controls (n=22) were recruited. Exhaled CO, peak expiratory flow (PEF) and FEV1 were measured daily (hospitalised cases) or once only (stable outpatients). Inpatients were managed without knowledge of the results. Exhaled CO levels in acute asthmatics (initial levels), stable asthmatics and controls were similar (median=2.0 ppm, h=5.05, p=0.08). In acute asthmatics, initial exhaled CO did not correlate with duration of hospitalisation, doses of intravenous corticosteroids, doses of nebulised salbutamol, PEF (% predicted) or FEV1 (% predicted). In stable asthmatics, exhaled CO did not correlate with corticosteroid dosage, PEF (% predicted) or FEV1 (% predicted). In the setting of acute hospitalised asthma patients, exhaled CO may not add any further to clinical management. This may in part be due to prior treatment with corticosteroids.

Cardiac output increases prior to development of pulmonary edema after re-expansion of spontaneous pneumothorax

Pulmonary edema following reexpansion of spontaneous pneumothorax is an uncommon complication. The underlying mechanism of this condition is unclear. We report the hemodynamic characteristics in a series of 7 male patients with spontaneous large (>50%) pneumothoraces of > or = 24 h and correlate the changes with reexpansion pulmonary edema (REPE). A pulmonary artery floatation catheter was inserted and hemodynamic data were obtained before therapeutic chest tube insertion, 1 h after chest tube insertion and the following day. Four (57%) patients developed REPE. There was a tendency for larger pneumothorax to develop REPE. Capillary wedge pressure did not change significantly 1 h after the insertion of chest tube in all our patients. Cardiac output increased significantly in patients who developed REPE compared to those who did not (+ 1.06 l/min vs -0.27 l/min; P = 0.03) 1 h after insertion of chest tube. One patient did not develop pulmonary edema despite having a large (> 80%) pneumothorax. His cardiac output did not rise 1 h after chest tube insertion. REPE is not an uncommon complication following chest tube drainage in patients with large and long-standing pneumothorax. The increase in cardiac output after chest tube insertion may be associated with subsequent development of REPE.

Detection of white spot syndrome virus (WSSV) of shrimp by means of monoclonal antibodies (MAbs) specific to an envelope protein (28 kDa)

The vp28 gene encoding an envelope protein (28 kDa) of white spot syndrome virus (WSSV) was amplified from WSSV-infected tiger shrimp that originated from Malaysia. Recombinant VP28 protein (r-28) was expressed in Escherichia coli and used as an antigen for preparation of monoclonal antibodies (MAbs). Three murine MAbs (6F6, 6H4 and 9C10) that were screened by r-28 antigen-based enzyme-linked immunosorbent assay (ELISA) were also able to recognize viral VP28 protein as well as r-28 on Western blot. Three non-overlapping epitopes of VP28 protein were determined using the MAbs in competitive ELISA; thus, an antigen-capture ELISA (Ac-ELISA) was developed by virtue of these MAbs. Ac-ELISA can differentiate WSSV-infected shrimp from uninfected shrimp and was further confirmed by a polymerase chain reaction (PCR) and Western blot. Approximately 400 pg of purified WSSV sample and 20 pg of r-28 could be detected by Ac-ELISA, which is comparable in sensitivity to PCR assay but more sensitive than Western blot in the detection of purified virus. Hemolymph and tissue homogenate samples collected from a shrimp farm in Malaysia during December 2000 and July 2001 were also detected by Ac-ELISA and PCR with corroborating results.

Bacteriologically-negative pulmonary tuberculosis--the Singapore tuberculosis control unit experience

INTRODUCTION

Patients with radiological features suggestive of active pulmonary tuberculosis (PTB) from areas with a high prevalence of the disease have a high clinical likelihood of PTB regardless of the bacteriological findings. It is the established practice in many countries to initiate therapy in such patients. Our study aimed to determine if treatment for bacteriologically-negative PTB in our local population was appropriate and to identify features at presentation that would be predictive of active PTB, as defined by good and appropriate response to anti-tuberculous treatment.

MATERIALS AND METHODS

A retrospective review of a randomised sample consisting of 100 bacteriologically-negative PTB patients given a course of anti-tuberculous treatment at the Singapore Tuberculosis Control Unit (TBCU). Based on their treatment response and outcome, patients were classified as probable active or unlikely active PTB. Patients' characteristics, clinical presentation and radiological findings were analysed for their association with likelihood of probable active PTB.

RESULTS

Fifty-six per cent of patients in this study had probable active PTB. The decision to treat this group of patient was appropriate. There was no serious adverse reaction in the patients treated. The presence of symptoms, especially cough at presentation, a history of contact with tuberculosis and cavitation on chest radiograph, were associated with an increase risk of probable active disease.

CONCLUSION

The TBCU's practice to treat patients suspected of having radiological PTB in the setting of negative sputum smear and culture seems to be appropriate in the majority of cases.

Dietary isothiocyanates, glutathione S-transferase -M1, -T1 polymorphisms and lung cancer risk among Chinese women in Singapore

Chinese populations consume a diet relatively high in isothiocyanates (ITCs), a derivative of cruciferous vegetables known to have cancer-protective effects. This class of compounds is metabolized by the glutathione S-transferase family of enzymes, which are also involved in the detoxification of tobacco-related carcinogens such as polycyclic aromatic hydrocarbons and alkyl halides. We evaluated the association between dietary isothiocyanate intake, GSTM1 and GSTT1 polymorphisms, and lung cancer risk in 420 Chinese women: 233 histologically confirmed lung cancer patients and 187 hospital controls. Among these, 58.8% of cases and 90.3% of controls were lifetime nonsmokers. An allele-specific PCR method was used to detect the presence or absence of the GSTM1 and GSTT1 genes in DNA isolated from peripheral blood. Higher weekly intake of ITCs (above the control median value of 53.0 micromol) reduced the risk of lung cancer to a greater extent in smokers [adjusted odds ratio (OR), 0.31; 95% confidence interval (CI), 0.10-0.98] than nonsmokers (OR, 0.70; 95% CI, 0.45-1.11). The inverse association was stronger among subjects with homozygous deletion of GSTM1 and/or GSTT1. Among nonsmokers with GSTM1-null genotype, higher intake of ITCs significantly reduced the risk of lung cancer (OR, 0.54; 95% CI, 0.30-0.95), an effect not seen among those with detectable GSTM1 (OR, 1.07; 95% CI, 0.50-2.29). Our results, in a Chinese female population, are consistent with the hypothesis that ITC is inversely related to the risk of lung cancer, and we show that among nonsmokers this effect may be primarily confined to GST-null individuals. Conjugation and elimination of ITCs is enhanced in GST-non-null relative to -null individuals, such that the GST metabolic genotype modifies the protective effect of ITCs on lung cancer development.

Interpretation of the tuberculin skin test in Mycobacterium bovis BCG-vaccinated Singaporean schoolchildren

Tuberculin skin test (TST) interpretation in Singapore is confounded by universal BCG vaccination at birth and by a revaccination policy for schoolchildren who are tuberculin nonreactors (TST < 10 mm, using 1 TU PPD RT 23) at 12 or 16 yr old, with not more than two BCG vaccinations given to any child. School health records for birth cohorts 1978 to 1984 indicate that 82.8% were revaccinated at age 12 yr. By collation with the national database of tuberculosis (TB) notifications, we examined the risk of TB disease in these cohorts for the 4 yr subsequent to TST reading at ages 12 and 16 yr respectively, in intervals of 0-4, 5-9, 10-14, 15-17, and >/= 18 mm. Receiver-operating curves (ROCs) were constructed to ascertain the optimum TST cutoffs in screening for the likelihood of development of TB disease. A cutoff of 10 mm performed best for the group tested at age 12 yr, whereas 16 mm was found to be optimum in those tested at age 16 yr (> 80% of whom were BCG revaccinated 4 yr earlier). We have extrapolated these findings to the screening of contacts, and utilized these cutoff points to guide the treatment of latent TB infection in this high-risk group.

A new asthma severity index: a predictor of near-fatal asthma?

Bronchial hyperresponsiveness (BHR), measured as the provocative dose of inhaled histamine or methacholine required to produce a 20% fall in forced expiratory volume in one second (FEV1) (PD20), is widely used as one of the indices of asthma severity. Excessive bronchoconstriction, reflected by the maximal percentage fall in forced vital capacity (FVC) at PD20 (deltaFVC %) during BHR testing, is considered to be the most important pathophysiological determinant in fatal asthma. The present study hypothesized that an index which combines both the ease of airway narrowing and excessive bronchoconstriction, deltaFVC %/log(PD20), may be better in assessing asthma severity, especially in those at risk of near-fatal attacks. The dose-response curves of 46 asthmatics who underwent methacholine challenge testing were studied. Group 1 (n=14) patients had mild disease, Group 2 (n=21) had moderate disease and Group 3 (n=11) had severe disease, as classified according to the Global Initiative for Asthma. Nine patients had prior intubation for near-fatal asthma. deltaFVC %/log (PD20) was better than deltaFVC % and PD20 in categorizing patients into the three severity groups (p<0.0001), but more importantly, it was able to discriminate patients with previous intubation from those without (p=0.04). It also correlated better with FEV1 (% predicted), frequency of symptoms and inhaled steroid requirement than either index alone. It is concluded that the percentage fall in forced vital capacity/log of the provocative dose causing a 20% fall in forced expiratory volume in one second combines information on the ease and excessive degrees of airway narrowing in asthma. This new index may be better at assessing asthma severity and in discriminating those at risk of near-fatal attacks.

Occupational asthma in Singapore

AIM

Since the first notified case of occupational asthma in 1983, a total of 90 cases were confirmed as on 31st December 1999. In this study, demographic data, causative agents and impact on the workers were described.

METHODS

The data was derived from notifications to the Ministry of Manpower and referrals to the Occupational Lung Disease Clinic jointly run with Department of Respiratory Medicine, Tan Tock Seng Hospital.

RESULTS

Of the 90 cases, 19 (21%) were females and 71 (79%) were males. There were 48 (53%) Chinese, 22 (24%) Malays, 14 (16%) Indians and 6 (7%) of other ethnic origins. The mean age at diagnosis was 35.8 +/- 9.3 yrs. The mean duration of exposure prior to onset of symptoms was 34.9 +/- 57.3 months. The most common causative agent was isocyanates (28 cases, 31%) followed by solder flux (12 cases, 13%) and welding fumes (8 cases, 9%) respectively. Thirteen (14.4%) workers were assessed to have permanent disability under the Workmen's Compensation Act.

CONCLUSIONS

Since 1990, occupational asthma has overtaken silicosis and asbestosis as the most common occupational lung disease in Singapore. The most common causative agent is isocyanates. Occupational asthma is a condition associated with disability in the workplace and may still be largely under-reported.

Deep vein thrombosis in patients admitted for exacerbation of chronic obstructive pulmonary disease

INTRODUCTION

There is a lack of data on the prevalence of deep vein thrombosis and pulmonary embolism in patients admitted to hospital for exacerbation of chronic obstructive pulmonary disease. Studies have found that most pulmonary embolism originate from deep vein thrombosis in the lower limbs, thus the prevalence of deep vein thrombosis may give an accurate reflection of the prevalence of pulmonary embolism. The aim of our study was to determine the prevalence of deep vein thrombosis in these patients, using duplex ultrasound of the lower limbs as the screening tool.

METHODS

Thirty-three male patients admitted to the general ward for exacerbation of chronic obstructive pulmonary disease were screened for presence of deep vein thrombosis of the lower limbs using duplex ultrasound scan.

RESULT

No patient in this study was found to have deep vein thrombosis of the lower limbs.

CONCLUSIONS

The prevalence of deep vein thrombosis in local patients admitted for exacerbation of chronic obstructive pulmonary disease is likely to be low. We do not recommend the use of duplex ultrasound to screen for deep vein thrombosis in this group of patients.

Impact of an asthma carepath on the management of acute asthma exacerbations

INTRODUCTION

Clinical pathways are being developed to standardise the management of acute asthma with the aim of improving asthma care. We evaluated the impact of an asthma carepath (CP), developed and instituted at a large community-based teaching hospital.

MATERIALS AND METHODS

Case records of consecutive asthma cases were reviewed after the implementation of a new asthma CP (November 1999 to March 2000). Data from July to October 1998 were used as historical control data [pre-carepath (pre-CP)]. Data collected included patient demographics, investigations performed, treatment prescribed, use of peak expiratory flow rate (PEFR) monitoring, length of stay (LOS) and asthma relapse rates.

RESULTS

One hundred and eighteen consecutive cases treated according to CP were compared with 67 pre-CP controls. There was no significant difference between the two groups with regard to LOS, use of PEFR monitoring, use of systemic steroids in hospital or asthma relapse after discharge (P > 0.05). A significant decrease in sputum tests (34.3% pre-CP versus 18.6% CP, P = 0.017) and use of antibiotics (62.7% pre-CP versus 30.4% CP, P < 0.001) was observed for patients on CP. The proportion of patients who had their salbutamol reviewed (49.3% pre-CP versus 73.7% CP, P = 0.001) and oxygen reviewed (25.8% pre-CP versus 73.8% CP, P = 0.004) was also significantly higher for cases on CP.

CONCLUSION

Although the asthma CP did not significantly reduce LOS or early relapse, it was associated with a significant reduction of the use of sputum tests and antibiotics. Review of salbutamol and oxygen as treatment was also more likely.

Simultaneous chromium(VI) reduction and phenol degradation in a fixed-film coculture bioreactor: reactor performance

Simultaneous Cr(VI) reduction and phenol degradation was observed in a fixed-film bioreactor consisting of a coculture of phenol-degrading bacteria, Pseudomonas putida DMP-1, and Cr(VI)-reducing bacteria, Escherichia coli ATCC 33456. Near complete Cr(VI) reduction and phenol degradation was observed during steady-state operation of the reactor under loadings of 5-21 mg Cr(VI) l-1 d-1 and 840-3350 mg phenol l-1 d-1. 2-hydroxymuconic semialdehyde (2HMSA), succinate, and acetate were the detected steady-state organic acid metabolites which accounted for 13-23% of TOC in the effluent. Optimum Cr(VI) reduction rate was observed under a Cr(VI) loading of approximately 26.5 mg Cr(VI) l-1 d-1 just before system overload. System overload was characterized by the increase in effluent Cr(VI) and phenol concentrations. System resilience to Cr(VI) toxicity was demonstrated by rapid recovery of biological activity and reduced effluent Cr(VI) and phenol concentrations after off-loading the system from overloaded conditions.

Force patterns of heel strike and toe off on different heel heights in normal walking

This study investigated the changes of force patterns of the heel strike and toe off phases at different heel heights during normal walking. Ten healthy female college students wore running shoes, flat leather shoes and high heeled shoes while walking on a Kistler force platform at their self-comfortable paces. It was found that the high heeled shoes and the leather shoes generated significantly greater vertical impact forces and anterior-posterior forces in the toe off phase than those in the heel strike phase. Accumulated impulses did not show significant increase while the heel heights increased and total support time while wearing the high heeled shoes was significantly longer than while wearing the running shoes.

Diffuse panbronchiolitis--a case report

Diffuse panbronchiolitis (DPB) is a chronic progressive obstructive disease of the airways. Of unknown aetiology, it is responsive to macrolide therapy. Although not uncommon among the Japanese, it is rare in other parts of the world. We report a case of DPB in a Chinese patient in Singapore.

LTP in a culture dish

The "aging" of populations in the developed world is rapidly altering demographics and presents a number of challenges for science and medicine. Foremost among these challenges is the need to enhance the quality of life for this "aging" majority. Paradoxically, improved prevention and treatment of diseases will only increase the number of individuals who will lose quality of life because of cognitive deficits in learning and memory. Such cognitive deficits are particularly vexing in societies where the ability to deal with information technology has become an increasing necessity. Understanding how the human brain encodes and stores information becomes critical in designing required therapeutic strategies.

Cloning and characterization of a novel variant of rat GABA(B)R1 with a truncated C-terminus

The gamma-aminobutyric acid B receptor (GABA(B)R) belong to the G-protein-coupled receptor superfamily and has been identified as a mediator in the transmission of slow inhibitory neurotransmission in the mammalian central nervous system. Two types of GABA(B)R have been cloned, GABA(B)R1 and R2. GABA(B)R2 is co-expressed with GABA(B)R1 in many brain regions and inwardly rectifying potassium channels are activated by GABA(B)R agonists only upon co-expression of GABA(B)R1 with GABA(B)R2. Several splice variants of GABA(B)R1 receptors have been cloned from rat brain library. Using a rat hippocampal cDNA library, we have isolated a novel cDNA clone of GABA(B) receptor containing an insert of 124 bp between exon 3 and exon 4. This insert occurred between the regions encoding the Sushi domain and leucine binding protein (LBP)-like domain. The insert and subsequent frame shift generated a cDNA that codes for a truncated polypeptide of 239 amino acids lacking the C-terminus. Analysis of the deduced amino acid sequence of the new cDNA clone, termed GABA(B)R1g, showed that it was identical to the first 157 amino acids of GABA(B)R1a, but diverged thereafter. The C-terminal region of GABA(B)R1g contained two cysteine residues. GABA(B)R1g was expressed in both brain and peripheral tissues. Northern blot analysis demonstrated that two transcripts (4.5 kb and 4.0 kb) exist in hippocampus. In addition, studies of hippocampus in developing animals indicated that the expression of GABA(B)R1g is maximal at postnatal day four. GABA(B)R1g could be generated by alternative splicing of the GABA(B)R1 gene.