Regional differences of tachykinin effects on smooth muscle and pacemaker potentials of the stomach, duodenum, ileum and colon of an emetic model, the house musk shrews

BACKGROUND AND AIMS

The contractile effects of tachykinins on the gastrointestinal tract are well-known, but how they modulate slow-waves, particularly in species capable of emesis, remains largely unknown. We aimed to elucidate the effects of tachykinins on myoelectric and contractile activity of isolated gastrointestinal tissues of the Suncus murinus.

METHODS

The effects of substance P (SP), neurokinin (NK)A, NKB and selective NK₁ (CP122,721, CP99,994), NK₂ (SR48,968, GR159,897) and NK₃ (SB218,795, SB222,200) receptor antagonists on isolated stomach, duodenum, ileum and colon segments were studied. Mechanical contractile activity was recorded using isometric force displacement transducers. Electrical pacemaker activity was recorded using a microelectrode array.

RESULTS

Compared with NKA, SP induced larger contractions in stomach tissue and smaller contractions in intestinal segments, where oscillation magnitudes increased in intestinal segments, but not the stomach. CP122,721 and GR159,897 inhibited electrical field stimulation-induced contractions of the stomach, ileum and colon. NKB and NK₃ had minor effects on contractile activity. The inhibitory potencies of SP and NKA on the peristaltic frequency of the colon and ileum, respectively, were correlated with those on electrical pacemaker frequency. SP, NKA and NKB inhibited pacemaker activity of the duodenum and ileum, but increased that of the stomach and colon. SP elicited a dose-dependent contradictive pacemaker frequency response in the colon.

CONCLUSION

This study revealed distinct effects of tachykinins on the mechanical and electrical properties of the stomach and colon vs. the proximal intestine, providing a unique aspect on neuromuscular correlation in terms of the effects of tachykinin on peristaltic and pacemaker activity in gastrointestinal-related symptoms.

Fast Ion-Beam Inactivation of Viruses, Where Radiation Track Structure Meets RNA Structural Biology

Here we show an interplay between the structures present in ionization tracks and nucleocapsid RNA structural biology, using fast ion-beam inactivation of the severe acute respiratory syndrome coronavirus (SARS-CoV) virion as an example. This interplay could be a key factor in predicting dose-inactivation curves for high-energy ion-beam inactivation of virions. We also investigate the adaptation of well-established cross-section data derived from radiation interactions with water to the interactions involving the components of a virion, going beyond the density-scaling approximation developed previously. We conclude that solving one of the grand challenges of structural biology - the determination of RNA tertiary/quaternary structure - is linked to predicting ion-beam inactivation of viruses and that the two problems can be mutually informative. Indeed, our simulations show that fast ion beams have a key role to play in elucidating RNA tertiary/quaternary structure.

Involvement of TRPV1 and TRPA1 in the modulation of pacemaker potentials in the mouse ileum

BACKGROUND

The roles of transient receptor potential cation channel, subfamily V, member 1 (TRPV1) and subfamily A, member 1 (TRPA1) in mechanisms of gastrointestinal motility are complex. This study aimed to clarify the effects of several TRPV1 and TRPA1 ligands on the electrical potentials generated by pacemaker cells in the mouse-isolated ileum.

METHOD

The pacemaker potentials of ileal segments of mice were recorded extracellularly using a 60-channel microelectrode array. The dominant frequencies, average waveform periods and propagation velocities were quantified. The effects of TRPV1 and TRPA1 agonist and antagonist were compared with the baseline recordings.

RESULTS

The electrophysiological recordings showed that capsaicin (30 μM to 3 mM), resiniferatoxin (300 μM), capsazepine (100-300 μM), allyl isothiocyanate (300 μM), isovelleral (300 μM), icilin (300 μM), A-967,079 (10 μM), AP18 (20 μM) and HC-030,031 (50 μM) significantly reduced the pacemaker frequency and increased the waveform period relative to the baseline. Conversely, ruthenium red (300 μM) significantly increased the pacemaker frequency and reduced the waveform period. Capsaicin (3 mM) and AP18 (20 μM) also significantly reduced the propagation velocity. However, all tested antagonists failed to inhibit the effects of agonists. AMG9810 (300 μM), but not A-967,079 (300 μM), significantly inhibited the increases in pacemaker frequency caused by increased temperatures.

CONCLUSION

Our findings suggest that TRPV1 and TRPA1 play a minor role in regulating pacemaker potentials and that at non-specific actions at other TRP and ion channels most likely contributed to the overall effects on the electrophysiological recordings that we observed.

Parenchyma-stromal interleukin-1 alpha and interleukin-6 overexpressions in ameloblastoma correlate with the aggressive phenotype

INTRODUCTION

Ameloblastoma is a benign but locally invasive odontogenic epithelial neoplasm with a high recurrence rate after treatment. The two main subsets encountered clinically are unicystic (UA) and solid/multicystic ameloblastoma (SMA). Currently neoplastic progression of many tumour types are believed to be related to parenchyma-stromal cell-cell interactions mediated by cytokines notably interleukins (IL). However their roles in ameloblastoma remain ill-understood.

MATERIALS AND METHODS

Thirty-nine formalin-fixed paraffin-embedded ameloblastoma cases comprising unicystic ameloblastoma (n=19) and solid/multicystic ameloblastoma (n=20) were subjected to IHC staining for IL-1α, IL-1β, IL-6 and IL-8. A semi-quantitative method was used to evaluate the expression levels of these cytokines according to cell types in the tumoural parenchyma and stroma.

RESULTS

Major findings were upregulations of IL-1α and IL-6 in SMA compared to UA. Both cytokines were heterogeneously detected in the tumoural parenchyma and stroma. Within the neoplastic epithelial compartment, IL-1α expression was more frequently detected in PA-like cells in UA whereas it was more frequently encountered in SR-like cells in SMA. IL-6 demonstrated higher expression levels in the stromal compartment of SMA. IL-1β and IL-8 were markedly underexpressed in both tumour subsets.

CONCLUSIONS

Overexpression of IL-1α in SMA suggests that this growth factor might play a role in promoting bone resorption and local invasiveness in this subtype. The expression levels of IL-1α and IL-6 in three cellular localizations indicate that parenchymal-stromal components of ameloblastoma interact reciprocally via IL-1α and IL-6 to create a microenvironment conducive for tumour progression.

Cognitive biases predict symptoms of depression, anxiety and wellbeing above and beyond neuroticism in adolescence

BACKGROUND

Adolescence represents a period of vulnerability to affective disorders. Neuroticism is considered a heritable risk factor for depression, but is not directly amenable to intervention. Therefore, it is important to identify the contributions of modifiable risk factors. Negative cognitive biases are implicated in the onset and maintenance of affective disorders in adults, and may represent modifiable risk factors in adolescence.

AIM(S)

This study sought to assess to what extent cognitive biases are able to predict depression, anxiety and wellbeing beyond that of neuroticism in adolescents.

METHODS

Adolescents (N = 99), recruited from Scottish secondary schools (54.5% female; mean age = 14.7), ensured a sample representing the breadth of the mental health spectrum. In line with prevalence estimates, 18% of this sample demonstrated clinical levels of depression symptoms. Cognitive biases of autobiographical memory, self-referential memory, ambiguous scenarios interpretation, facial expression recognition, rumination and dysfunctional attitudes were assessed. Depression, anxiety, and wellbeing were indexed using the Mood and Feelings Questionnaire, Spence Children's Anxiety Scale and the BBC Subjective Wellbeing Scale.

RESULTS

Regression analyses demonstrated neuroticism to significantly predict depression, anxiety and wellbeing. The addition of cognitive biases resulted in a significant increase of explained variance with final models explaining just over 50% of variances of depression, anxiety and wellbeing.

CONCLUSION

These findings demonstrate that cognitive biases explain mental health symptoms over and above that of neuroticism. Depressive symptomology was particularly related to self-referential memory bias, while anxiety was predicted by interpretive bias. The key clinical implication is that targeting specific biases based on diagnostic features may be of particular benefit in alleviating distress and promoting wellbeing.

Uptake and protective effects of ergothioneine in human endothelial cells

Ergothioneine is a thiourea derivative of histidine found in food, especially mushrooms. Experiments in cell-free systems and chemical assays identified this compound as a powerful antioxidant. Experiments were designed to test the ability of endothelial cells to take up ergothioneine and hence benefit from protection against oxidative stress. Reverse-transcription polymerase chain reaction and Western blotting demonstrated transcription and translation of an ergothioneine transporter in human brain microvascular endothelial cells (HBMECs). Uptake of [(3)H]ergothioneine occurred by the organic cation transporter novel type-1 (OCTN-1), was sodium-dependent, and was reduced when expression of OCTN-1 was silenced by small interfering RNA (siRNA). The effect of ergothioneine on the production of reactive oxygen species (ROS) in HBMECs was measured using dichlorodihydrofluorescein and lucigenin, and the effect on cell viability was studied using the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay. ROS production and cell death induced by pyrogallol, xanthine oxidase plus xanthine, and high glucose were suppressed by ergothioneine. The antioxidant and cytoprotective effects of ergothioneine were abolished when OCTN-1 was silenced using siRNA. The expression of NADPH oxidase 1 was decreased, and those of glutathione reductase, catalase, and superoxide dismutase enhanced by the compound. In isolated rat basilar arteries, ergothioneine attenuated the reduction in acetylcholine-induced relaxation caused by pyrogallol, xanthine oxidase plus xanthine, or incubation in high glucose. Chronic treatment with the compound improved the response to acetylcholine in arteries of rats with streptozotocin-induced diabetes. In summary, ergothioneine is taken up by endothelial cells via OCTN-1, where the compound then protects against oxidative stress, curtailing endothelial dysfunction.

Accelerating ovarian age: cancer treatment in the premenopausal woman

The reproductive sequelae of cancer treatments may provide an important model of accelerated ovarian aging. Tens of thousands of women treated for cancer each year experience infertility and early menopause as a result of treatment. A spectrum of reproductive compromise commonly ranges from immediate menopause at the time of cancer treatment to the less proximate outcome of early menopause in the years to decades after treatment. A woman's reproductive lifespan can be shortened after chemotherapy or radiation because such treatments likely decrease the number of viable eggs after treatment. This acceleration in the decline of the number of follicles leads to increased rates of not only infertility and miscarriage but also early menopause, which represents the most extreme form of accelerated ovarian aging. The degree of reproductive impairment is dependent on chronologic age and the diagnosis or treatment. The variation in outcomes that persist may be partially explained by pretreatment ovarian reserve. Establishing the use of clinical predictors such as ovarian reserve markers to effectively anticipate such outcomes is an obvious and important keystone in the foundation of cancer survivorship research. An improved understanding of cancer treatment's ability to accelerate follicle death, decrease fecundability, and initiate an earlier menopause could provide a clinically relevant, time-shortened, and reproducible snapshot into the basic biology of ovarian aging.

Collaboration between hospital physicians and nurses: an integrated literature review

BACKGROUND

Ineffective physician-nurse collaboration has been shown to cause work dissatisfaction among physicians and nurses and compromised the quality of patient care.

AIM

The review sought to explore: (1) attitudes of physicians and nurses toward physician-nurse collaboration; (2) factors affecting physician-nurse collaboration; and (3) strategies to improve physician-nurse collaboration.

METHODS

A literature search was conducted in the following databases: CINAHL, PubMed, Wiley Online Library and Scopus from year 2002 to 2012, to include papers that reported studies on physician-nurse collaboration in the hospital setting.

FINDINGS

Seventeen papers were included in this review. Three of the reviewed articles were qualitative studies and the other 14 were quantitative studies. Three key themes emerged from this review: (1) attitudes towards physician-nurse collaboration, where physicians viewed physician-nurse collaboration as less important than nurses but rated the quality of collaboration higher than nurses; (2) factors affecting physician-nurse collaboration, including communication, respect and trust, unequal power, understanding professional roles, and task prioritizing; and (3) improvement strategies for physician-nurse collaboration, involving inter-professional education and interdisciplinary ward rounds.

CONCLUSION

This review has highlighted important aspects of physician-nurse collaboration that could be addressed by future research studies. These include: developing a comprehensive instrument to assess collaboration in greater depth; conducting rigorous intervention studies to evaluate the effectiveness of improvement strategies for physician-nurse collaboration; and examining the role of senior physicians and nurses in facilitating collaboration among junior physicians and nurses. Other implications include inter-professional education to empower nurses in making clinical decisions and putting in place policies to resolve workplace issues.

Involvement of organic cation transporter-3 and plasma membrane monoamine transporter in serotonin uptake in human brain vascular smooth muscle cells

The serotonin (5-HT) uptake system is supposed to play a crucial part in vascular functions by “fine-tuning” the local concentration of 5-HT in the vicinity of 5-HT₂ receptors in vascular smooth muscle cells. In this study, the mechanism of 5-HT uptake in human brain vascular smooth muscle cells (HBVSMCs) was investigated. [³H]5-HT uptake in HBVSMCs was Na⁺-independent. Kinetic analyses of [³H]5-HT uptake in HBVSMCs revealed a K_m of 50.36 ± 10.2 mM and a V_max of 1033.61 ± 98.86 pmol/mg protein/min. The specific serotonin re-uptake transporter (SERT) inhibitor citalopram, the specific norepinephrine transporter (NET) inhibitor desipramine, and the dopamine transporter (DAT) inhibitor GBR12935 inhibited 5-HT uptake in HBVSMCs with IC₅₀ values of 97.03 ± 40.10, 10.49 ± 5.98, and 2.80 ± 1.04 μM, respectively. These IC₅₀ values were 100-fold higher than data reported by other authors, suggesting that those inhibitors were not blocking their corresponding transporters. Reverse transcription-polymerase chain reaction results demonstrated the presence of mRNA for organic cation transporter (OCT)-3 and plasma membrane monoamine transporter (PMAT), but the absence of OCT-1, OCT-2, SERT, NET, and DAT. siRNA knockdown of OCT-3 and PMAT specifically attenuated 5-HT uptake in HBVSMCs. It is concluded that 5-HT uptake in HBVSMCs was mediated predominantly by a low-affinity and Na⁺-independent mechanism. The most probable candidates are OCT-3 and PMAT, but not the SERT.

Guidelines for the treatment of myelodysplastic syndromes (MDS) in South Africa

INTRODUCTION

Myelodysplastic syndromes (MDS) encompass a heterogeneous group of clonal haematopoietic disorders characterised by chronic and progressive cytopenias resulting from ineffective haematopoiesis. Treatment is complicated by differences in disease mechanisms in different subgroups, variable clinical phenotypes and risk of progression to acute myeloid leukaemia.

RATIONALE

Changes in disease classification, prognostic scoring systems, the availability of novel treatment options and the absence of South African guidelines for the diagnosis and management of these complex disorders underpinned the need for the development of these recommendations.

METHODS

These recommendations are based on the opinion of a number of experts in the field from the laboratory as well as clinical settings and came from both the private and institutional academic environments. The most recent literature as well as available guidelines from other countries were discussed and debated at a number of different meetings held over a 2-year period.

RESULTS

A comprehensive set of recommendations was developed focusing on risk stratification, supportive management and specific treatment. Novel agents and their indications are discussed and recommendations are made based on best available evidence and taking into account the availability of treatments in South Africa.

CONCLUSION

Correct diagnosis, risk stratification and appropriate therapeutic choices are the cornerstones of success in the management of patients with myelodysplastic syndromes.

Hepatocarcinogenesis of regenerative and dysplastic nodules in Chinese patients

OBJECTIVES

To determine the development rate of hepatocellular carcinoma and survival of patients diagnosed to have regenerative, and low-grade and high-grade dysplastic liver nodules.

DESIGN

Retrospective descriptive study.

SETTING

Acute public hospital, Hong Kong.

PATIENTS

Patients with non-malignant liver nodules confirmed by imaging-guided liver biopsy between January 1997 and December 2008.

MAIN OUTCOME MEASURES

Rates of hepatocellular carcinoma development and survival.

RESULTS

A total of 147 patients with non-malignant liver nodules were followed up over a median duration of 29 months. The initial histological diagnosis included regenerative nodules (n=74), low-grade dysplastic nodules (n=34), and high-grade dysplastic nodules (n=39). The respective cumulative hepatocellular carcinoma development rate during the first, second, third, and fourth year were 3%, 5%, 9% and 12% for simple regenerative nodules, 29%, 35%, 38% and 44% for low-grade dysplastic nodules, and 38%, 41%, 51% and 51% for high-grade dysplastic nodules. The hepatocellular carcinoma development rate was highest in those with high-grade dysplastic nodules. Multivariate analysis showed that histological dysplastic changes were associated with increased alpha-fetoprotein levels and advanced age, which were both independent predictors of hepatocellular carcinoma development. Histological dysplastic changes, male sex, advanced age, prolonged prothrombin time, and ultrasound appearances were independent predictors of mortality.

CONCLUSION

The presence of dysplastic change in liver nodules increased the risk of hepatocellular carcinoma development and death.

WW domain-mediated interaction with Wbp2 is important for the oncogenic property of TAZ

The transcriptional co-activators YAP and TAZ are downstream targets inhibited by the Hippo tumor suppressor pathway. YAP and TAZ both possess WW domains, which are important protein–protein interaction modules that mediate interaction with proline-rich motifs, most commonly PPXY. The WW domains of YAP have complex regulatory roles as exemplified by recent reports showing that they can positively or negatively influence YAP activity in a cell and context-specific manner. In this study, we show that the WW domain of TAZ is important for it to transform both MCF10A and NIH3T3 cells and to activate transcription of ITGB2 but not CTGF, as introducing point mutations into the WW domain of TAZ (WWm) abolished its transforming and transcription-promoting ability. Using a proteomic approach, we discovered potential regulatory proteins that interact with TAZ WW domain and identified Wbp2. The interaction of Wbp2 with TAZ is dependent on the WW domain of TAZ and the PPXY-containing C-terminal region of Wbp2. Knockdown of endogenous Wbp2 suppresses, whereas overexpression of Wbp2 enhances, TAZ-driven transformation. Forced interaction of WWm with Wbp2 by direct C-terminal fusion of full-length Wbp2 or its TAZ-interacting C-terminal domain restored the transforming and transcription-promoting ability of TAZ. These results suggest that the WW domain-mediated interaction with Wbp2 promotes the transforming ability of TAZ.

The complement system of the duck

Antibody (Ab)-dependent and-independent activation of the duck complement (C') system were studied. Ab-independent C' activity exhibited characteristics similar to those of the mammalian alternative C' pathway (ACP), including the selective lysis of rabbit erythrocytes (RRBC), a requirement for Mg2+, but not Ca2+, depletion of activity by zymosan, and lack of sensitivity to the mammalian C1 inhibitor carrageenan. Measurement of C' activity using antisera against sheep erythrocytes (SRBC) revealed that duck Abs activate C' by a pathway resembling the mammalian classical pathway (CCP) requiring both Ca2+ and Mg2+. Ab-dependent and-independent activities were further distinguishable by their kinetics of lysis and sensitivities to heat. Duck Abs were also found to activate C' in normal and carrageenan-treated serum by a mechanism that requires only Mg2+, and thus resembles the ACP. However, this Ab-dependent ACP-like activity exhibits patterns of ionic strength dependence and ontogeny which are clearly different from those of the conventional ACP and CCP. These findings indicate that duck C' can be activated by three mechanisms: Ab-mediated activation of the CCP, and Ab-mediated and Ab-independent activation of the ACP. Duck Ab responses to SRBC and RRBC were followed by direct agglutination, antiglobulin agglutination, and activation of the CCP and ACP. While the C'-activating abilities of duck anti-SRBC Abs persisted through a 3-month programme of inoculation, the anti-RRBC response lost its ability to activate C' after 2 weeks.

Atmospheric radon in Hong Kong

For the first time in Hong Kong, atmospheric radon concentration was continuously monitored between November 2007 and October 2008. This paper presents the results obtained during the 12-month period. The annual mean atmospheric radon concentration in Hong Kong was found to be 9.3 Bqm(-3) which was close to the level at neighbouring places like Guangdong and Taiwan. An estimation of the dose arising from atmospheric radon to the Hong Kong population was made. The meteorological effects on the variation of atmospheric radon concentration were discussed. It was found that the origin of the airmass and stability of the local atmosphere played vital roles in the seasonal and diurnal variations respectively, whereas precipitation caused abrupt changes in rainy days. An attempt was also made to find out the contribution of atmospheric radon to the ambient gamma dose rate.

Novel hypoglycemic effects of Ganoderma lucidum water-extract in obese/diabetic (+db/+db) mice

In this study, we evaluated the pharmacological effects of Ganoderma lucidum (G. lucidum) (water-extract) (0.003, 0.03 and 0.3g/kg, 4-week oral gavage) consumption using the lean (+db/+m) and the obese/diabetic (+db/+db) mice. Different physiological parameters (plasma glucose and insulin levels, lipoproteins-cholesterol levels, phosphoenolpyruvate carboxykinase (PEPCK), 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG CoA reductase) and isolated aorta relaxation of both species were measured and compared. G. lucidum (0.03 and 0.3g/kg) lowered the serum glucose level in +db/+db mice after the first week of treatment whereas a reduction was observed in +db/+m mice only fed with 0.3g/kg of G. lucidum at the fourth week. A higher hepatic PEPCK gene expression was found in +db/+db mice. G. lucidum (0.03 and 0.3g/kg) markedly reduced the PEPCK expression in +db/+db mice whereas the expression of PEPCK was attenuated in +db/+m mice (0.3g/kg G. lucidum). HMG CoA reductase protein expression (in both hepatic and extra-hepatic organs) and the serum insulin level were not altered by G. lucidum. These data demonstrate that G. lucidum consumption can provide beneficial effects in treating type 2 diabetes mellitus (T2DM) by lowering the serum glucose levels through the suppression of the hepatic PEPCK gene expression.

An innovative web-based peer support system for medical students in Hong Kong

BACKGROUND

Psychological morbidity is commonly found in medical students.

AIMS

The Mental Health Support Group (MSG), a student-initiated and student-run web-based peer support service aims to provide mental health information, e mail counseling and an online forum for medical students.

METHODS

The development process of MSG is described in the paper with presentation of preliminary evaluation results.

RESULTS

Preliminary evaluation shows promising results. Student members of MSG acquired valuable skills in counseling, communication, webpage design and maintenance of an online forum.

CONCLUSIONS

Future challenges include succession issues, strategies to keep up the momentum, enhancement of publicity and further diversification of service to meet the needs of our students.

Modulation by simvastatin of iberiotoxin-sensitive, Ca2+-activated K+ channels of porcine coronary artery smooth muscle cells

BACKGROUND AND PURPOSE

Statins (3-hydroxy-3-methyl-glutaryl coenzyme A (HMG CoA) reductase inhibitors) have been demonstrated to reduce cardiovascular mortality. It is unclear how the expression level of HMG CoA reductase in cardiovascular tissues compares with that in cells derived from the liver. We hypothesized that this enzyme exists in different cardiovascular tissues, and simvastatin modulates the vascular iberiotoxin-sensitive Ca2+-activated K(+) (BK(Ca)) channels.

EXPERIMENTAL APPROACHES

Expression of HMG CoA reductase in different cardiovascular preparations was measured. Effects of simvastatin on BK(Ca) channel gatings of porcine coronary artery smooth muscle cells were evaluated.

KEY RESULTS

Western immunoblots revealed the biochemical existence of HMG CoA reductase in human cardiovascular tissues and porcine coronary artery. In porcine coronary artery smooth muscle cells, extracellular simvastatin (1, 3 and 10 microM) (hydrophobic), but not simvastatin Na+ (hydrophilic), inhibited the BK(Ca) channels with a minimal recovery upon washout. Isopimaric acid (10 microM)-mediated enhancement of the BK(Ca) amplitude was reversed by external simvastatin. Simvastatin Na+ (10 microM, applied internally), markedly attenuated isopimaric acid (10 microM)-induced enhancement of the BK(Ca) amplitude. Reduced glutathione (5 mM; in the pipette solution) abolished simvastatin -elicited inhibition. Mevalonolactone (500 microM) and geranylgeranyl pyrophosphate (20 microM) only prevented simvastatin (1 and 3 microM)-induced responses. simvastatin (10 microM ) caused a rottlerin (1 microM)-sensitive (cycloheximide (10 microM)-insensitive) increase of PKC-delta protein expression.

CONCLUSIONS AND IMPLICATIONS

Our results demonstrated the biochemical presence of HMG CoA reductase in different cardiovascular tissues, and that simvastatin inhibited the BK(Ca) channels of the arterial smooth muscle cells through multiple intracellular pathways.

Nonspecular effects on reflection from absorbing media at and around Brewster's dip

We show that, for a TM (or p-state) Gaussian beam incident onto an absorbing medium at and around Brewster's dip, the reflected beam always remains Gaussian and undergoes a Goos-Hänchen-like (GH) shift, an angular shift, a focal shift, and a beam-waist modification, provided that the beam is sufficiently collimated that the third-order change of the (logarithmic) reflection coefficient can be ignored in the angular range of beam divergence. For weak absorption, not only are a large negative GH shift and an odd-functioned-like focal shift with greater magnitude found but also the angular shift, though small by itself, is shown to give an even larger lateral net shift at a distance beyond the Rayleigh range.

Modulation by homocysteine of the iberiotoxin-sensitive, Ca2+ -activated K+ channels of porcine coronary artery smooth muscle cells

We evaluated the acute effect of homocysteine on the iberiotoxin-sensitive, Ca(2+)-activated K(+) (BK(Ca)) channels of the porcine coronary artery smooth muscle cells. NS 1619 (1 to 30 microM) caused a concentration-dependent enhancement of the BK(Ca) amplitude (recorded using the whole-cell, membrane-rupture configuration) only with an elevated [Ca(2+)](i) of approximately 444 nM, but not with [Ca(2+)](i) of approximately 100 nM. Homocysteine (30 microM) caused a small inhibition ( approximately 16%) of the BK(Ca) amplitude ([Ca(2+)](i)= approximately 444 nM), and a greater inhibition ( approximately 77%) was observed with 100 microM NADH present in the pipette solution. The inhibition persisted after washing. With NADPH (100 microM), a smaller magnitude of inhibition ( approximately 34%) of the BK(Ca) amplitude was recorded. The NS 1619-mediated enhancement of the BK(Ca) amplitude (with elevated [Ca(2+)](i) plus NADH in the pipette) was attenuated by homocysteine. The homocysteine-mediated inhibition of the BK(Ca) amplitude was suppressed by Tiron (10 mM) or diphenylene iodonium (30 nM), applied alone, but not by superoxide dismutase (500 U/ml) and catalase (500 U/ml). Generation of superoxide (O(2)(-)) of the smooth muscle cells (with NADH presence), measured using the lucigenin-enhanced chemiluminescence, was markedly increased by angiotensin II (100 nM) and homocysteine (30 microM). The chemiluminescence signal was sensitive to apocynin (300 microM) or Tiron, applied alone, but not to superoxide dismutase and catalase. In conclusion, our results demonstrate that acute homocysteine application inhibits the iberiotoxin-sensitive BK(Ca) channels (with elevated [Ca(2+)](i) and NADH present) which is probably caused by the NADH oxidase activation and the concomitant generation of intracellular superoxide.

Topical 5-fluorouracil has no additional benefit in treating common warts with cryotherapy: a single-centre, double-blind, randomized, placebo-controlled trial

The role of topical 5-fluorouracil (5-FU) in treating common warts is not well defined. We tried to evaluate the efficacy and adverse effects of combination cryotherapy and topical 5% 5-FU ointment in the treatment of common warts. The study was a single-centre, double-blind randomized placebo-controlled trial. In the study, 80 patients with common warts were randomized into two groups and underwent two 10-second freeze/thaw cycles of cryotherapy with liquid nitrogen once every three weeks for a maximum of five treatments. Between treatments, patients applied either topical 5% 5-FU ointment (group A) or placebo aqueous cream (group B) twice daily. The mean +/- SD reduction in wart area was 58.57 +/- 0.06% in group A and 65.29 +/- 0.06% in group B. In total, 19 patients in group A and 24 patients in group B had wart size reduced by 75% or more (P = 0.50), while 12 patients in group A and 17 patients in group B had clearance of their warts (P = 0.245). Logistic regression with age, sex, smoking status, immune status, site, duration and number of warty lesions, history of previous treatment, and treatment group found that only a history of previous treatment and acral lesions were significant adverse predictors of improvement. There was no significant difference in the number of adverse events between the two groups, although there was a trend towards more pain and blistering associated with topical 5-FU. We concluded that topical 5-FU has no added benefit in treating common warts with cryotherapy.

Large and negative Goos-Hänchen shift near the Brewster dip on reflection from weakly absorbing media

Applying Artmann's formula to a light beam in the TM state of wave polarization, we show analytically the existence of a large and negative Goos-Hänchen shift near the angle of the Brewster dip on reflection from a weakly absorbing semi-infinite medium. The shift is opposite that in the case of total internal reflection, and it can be an order of magnitude larger than a wavelength if the absorption of the reflecting medium is sufficiently weak. Examples are given, and the detectibility of the shift is discussed.

Classical and variant Creutzfeldt-Jakob diseases and their potential impact on the practice of clinical dentistry in Australia

Following recent published evidence regarding the experimental transmission of prion diseases via blood transfusion, dental practitioners have expressed their concern about the potential impact of these transmissible spongiform encephalopathies on dental care provision. This review provides updated information on Creutzfeldt-Jakob disease and related disorders and highlights their potential significance for the practice of clinical dentistry. The current guidelines in Australia relating to infection control and clinical dental procedures are discussed together with recommended guidelines and considerations from the United Kingdom and the World Health Organization (WHO).

Chromatographic analysis of Fritillaria isosteroidal alkaloids, the active ingredients of Beimu, the antitussive traditional Chinese medicinal herb

Bulbus Fritillariae derived from plants of various Fritillaria species is the most commonly used antitussive traditional Chinese medicinal herb and is called Beimu. Herbs derived from similar and/or different species of Fritillaria are also used in Japan and Turkey as traditional or folk medicines. Isosteroidal alkaloids are the main bioactive ingredients in Fritillaria species. As the contents and structure types of these bioactive alkaloids vary in different Fritillaria species, quality control of these active principles in herbal Beimu is very important to ensure its safe and effective clinical use. This review describes the development of chromatographic analyses for the simultaneous qualitative and quantitative determination of the main bioactive Fritillaria isosteroidal alkaloids in herbal and biological samples. The recently developed direct HPLC-evaporative light scattering detection method is the most simple, selective and sensitive assay, and is readily used as a suitable quality control method for the analysis of the active principles of herbal Beimu.

Metastatic thyroid carcinoma in the presence of struma ovarii

A 27-year-old woman presented with metastatic follicular carcinoma of thyroid cell type. Assessment was complicated by recent surgery for "benign" struma ovarii. She underwent total thyroidectomy which failed to show a neoplasm, leaving the struma ovarii as the likely source of the metastasis.

A polymorphism of the human matrix gamma-carboxyglutamic acid protein promoter alters binding of an activating protein-1 complex and is associated with altered transcription and serum levels

Matrix gamma-carboxyglutamic acid protein (MGP) is a mineral-binding extracellular matrix protein synthesized by vascular smooth muscle cells (VSMCs) and chondrocytes that is thought to be a key regulator of tissue calcification. In this study, we identified four polymorphisms in the promoter region of the human MGP gene. Transfection studies showed that the G-7A and T-138C polymorphisms have an important impact on in vitro promoter activity when transiently transfected into VSMCs. We found that one of these polymorphisms (T-138C) is significantly correlated with serum MGP levels in human subjects. Promoter deletion analysis showed that this polymorphism lies in a region of the promoter critical for transcription in VSMCs. This region contains a potential activating protein-1 (AP-1) binding element located between -142 and -136. We have demonstrated that the T-138C polymorphism results in altered binding of an AP-1 complex to this region. The -138T allelic variant binds AP-1 complexes consisting primarily of c-Jun, JunB and its partners Fra-1 and Fra-2 in rat VSMC. Furthermore, the -138T variant form of the promoter was induced following phorbol 12-myristate 13-acetate treatment, while the -138C variant was refractive to phorbol 12-myristate 13-acetate treatment, confirming that AP-1 factors preferentially bind to the -138T variant. This study therefore suggests that a common polymorphism of the MGP promoter influences binding of the AP-1 complex, which may lead to altered transcription and serum levels. This could have important implications for diseases such as atherosclerosis and aortic valve stenosis, since it strongly suggests a genetic basis for regulation of tissue calcification.

Altering telomere structure allows telomerase to act in yeast lacking ATM kinases

BACKGROUND

Telomerase is a ribonucleoprotein that copies a short RNA template into telomeric DNA, maintaining eukaryotic chromosome ends and preventing replicative senescence. Telomeres differentiate chromosome ends from DNA double-stranded breaks. Nevertheless, the DNA damage-responsive ATM kinases Tel1p and Mec1p are required for normal telomere maintenance in Saccharomyces cerevisiae. We tested whether the ATM kinases are required for telomerase enzyme activity or whether it is their action on the telomere that allows telomeric DNA synthesis.

RESULTS

Cells lacking Tel1p and Mec1p had wild-type levels of telomerase activity in vitro. Furthermore, altering telomere structure in three different ways showed that telomerase can function in ATM kinase-deleted cells: tel1 mec1 cells senesced more slowly than tel1 mec1 cells that also lacked TLC1, which encodes telomerase RNA, suggesting that tel1 mec1 cells have residual telomerase function; deleting the telomere-associated proteins Rif1p and Rif2p in tel1 mec1 cells prevented senescence; we isolated a point mutation in the telomerase RNA template domain (tlc1-476A) that altered telomeric DNA sequences, causing uncontrolled telomeric DNA elongation and increasing single strandedness. In tel1 mec1 cells, tlc1-476A telomerase was also capable of uncontrolled synthesis, but only after telomeres had shortened for >30 generations.

CONCLUSION

Our results show that, without Tel1p and Mec1p, telomerase is still active and can act in vivo when the telomere structure is disrupted by various means. Hence, a primary function of the ATM-family kinases in telomere maintenance is to act on the substrate of telomerase, the telomere, rather than to activate the enzymatic activity of telomerase.

Simian virus 40 Vp1 DNA-binding domain is functionally separable from the overlapping nuclear localization signal and is required for effective virion formation and full viability

A DNA-binding domain (DBD) was identified on simian virus 40 (SV40) major capsid protein Vp1, and the domain's function in the SV40 life cycle was examined. The DBD was mapped by assaying various recombinant Vp1 proteins for DNA binding in vitro. The carboxy-terminal 58-residue truncated Vp1DeltaC58 pentamer bound DNA with a K(d) of 1.8 x 10(-9) M in terms of the protein pentamer, while full-length Vp1 and carboxy-terminal-17-truncated Vp1DeltaC17 had comparable apparent K(d)s of 5.3 x 10(-9) to 7.3 x 10(-9) M in terms of the protein monomers. Previously identified on Vp1 was a nuclear localization signal (NLS) consisting of two N-terminal basic clusters, NLS1 (4-KRK-6) and NLS2 (15-KKPK-18). Vp1DeltaC58 pentamers harboring multiple-point mutations in NLS1 (NLSm1), NLS2 (NLSm2), or both basic clusters (NLSm1. 2) had progressively decreased DNA-binding activity, down to 0.7% of the Vp1DeltaC58 level for NLSm1. 2 Vp1. These data, along with those of N-terminally truncated proteins, placed the DBD in overlap with the bipartite NLS. The role of the Vp1 DBD during infection was investigated by taking advantage of NLS phenotypic complementation (N. Ishii, A. Nakanishi, M. Yamada, M. H. Macalalad, and H. Kasamatsu, J. Virol. 68:8209-8216, 1994), in which an NLS-defective Vp1 could localize to the nucleus in the presence of wild-type minor capsid proteins Vp2 and Vp3. This approach made it possible to dissect the role of the bifunctional Vp1 NLS-DBD in virion assembly in the nucleus. Mutants of the viable nonoverlapping SV40 (NO-SV40) DNA NLSm1, NLSm2, and NLSm1. 2 replicated normally following transfection into host cells and produced capsid proteins at normal levels. All mutant Vp1s were able to interact with Vp3 in vitro. The mutants NLSm1 and NLSm1. 2 were nonviable, and the mutant Vp1s unexpectedly failed to localize to the nucleus though Vp2 and Vp3 did, suggesting that the mutated NLS1 acted as a dominant signal for the cytoplasmic localization of Vp1. Mutant NLSm2, for which the mutant Vp1's nuclear localization defect was complemented by Vp2 and Vp3, displayed a 5,000-fold reduced viability. Analysis of NLSm2 DNA-transfected cell lysate revealed a 10-fold reduction in the level of DNase I-protected viral DNA, and yet virion-like particles were found among the DNase I-resistant material. Collective results support a role for Vp1 NLS2-DBD2 in the assembly of virion particles. The results also suggest that this determinant can function in the infection of new cells.

Retinoblastoma-binding Protein 2 (Rbp2) Potentiates Nuclear Hormone Receptor-mediated Transcription

Retinoblastoma-binding protein 2 (Rbp2) was originally identified as a retinoblastoma protein (RB) pocket domain-binding protein. Although Rbp2 has been shown to interact with RB, p107, TATA-binding protein, and T-cell oncogene rhombotin-2, the physiological function of Rbp2 remains unclear. Here we demonstrate that Rbp2 not only binds to nuclear receptors (NRs) but also enhances the transcription mediated by them. Rbp2 interacts with the DNA-binding domains of NRs and potentiates NR-mediated transcription in an AF-2-dependent manner. Both the N-terminal and C-terminal domains of Rbp2 are critical for the transactivation activity of Rbp2 on NRs. The C terminus is the NR-interacting region. In addition, RB functions in maximizing the effect of Rbp2 on the transcription by NRs. These results suggest that Rbp2 is a coregulator of NRs and define a potential role for Rbp2 in NR-mediated transcription.

Retinoblastoma protein is functionally distinct from its homologues in affecting glucocorticoid receptor-mediated transcription and apoptosis

The cell cycle regulator, retinoblastoma protein, is known to potentiate glucocorticoid receptor-activated transcription through the interaction of its pocket domain with the transcription coactivator, hBRM. We now show that glucocorticoid receptor-induced apoptosis is also dependent on both the retinoblastoma protein and hBRM. p107 and p130, which share extensive sequence homology with the pocket domain of the retinoblastoma protein but not its N-terminal region, also interact with hBRM but do not support either glucocorticoid receptor-dependent activity. This difference arises from the divergent N-terminal domain of the retinoblastoma protein, which, when fused to the pocket domains, confers upon p107 and p130 the ability to influence glucocorticoid receptor activities. This effect probably results from the promotion of glucocorticoid receptor-targeted chromatin remodeling by the hBRM-containing SWI/SNF complex because the N-terminal domain of the retinoblastoma protein enhances glucocorticoid receptor-hBRM interactions. These results highlight that, besides the interaction between hBRM and the pocket domain of RB, the N-terminal region of the retinoblastoma protein is also essential for glucocorticoid receptor-induced apoptosis and the potentiation of glucocorticoid receptor-mediated transcription and provide a basis for functional distinction between the retinoblastoma protein and its homologues.

Action of glucocorticoids to antagonise cisplatin-induced acute and delayed emesis in the ferret

Cisplatin 5 mg/kg, i.p. induced an acute (day 1) and delayed (days 2 and 3) emetic response in the ferret that was used to investigate the potential anti-emetic activity of several glucocorticoids. Betamethasone (0.3-3 mg/kg, i.p.) reduced the emesis occurring during the initial 0-24-h period by 71.1-99.5% (P<0.05). The action of methylprednisolone (1.0-10.0 mg/kg, i.p.) and hydrocortisone (1.0-30.0 mg/kg, i.p.) could not be assessed because the controls exhibited weak emetic responses and dexamethasone produced a non-significant 64.0% reduction at 0.3 mg/kg (P>0.05). However, all glucocorticoids dose-dependently reduced retching+vomiting during the subsequent 24-56-h period. The rank order of anti-emetic potency was betamethasone (ID(80)<0.3 mg/kg)>/=dexamethasone (ID(80)=0.32 mg/kg)>methylprednisolone (ID(80)=0.66 mg/kg)&z.Gt;hydrocortisone (ID(80)>30 mg/kg). Dexamethasone was ineffective to antagonise the retching+vomiting response during the 24-56-h period when the administration was delayed until 24 h post-cisplatin injection. None of the glucocorticoids reduced the retching+vomiting response occurring during the 56-72-h period. In conclusion, the rank order of anti-emetic potency suggests that inflammation, or mediators of inflammation, contribute to the retching+vomiting response induced by cisplatin.

The Mediterranean score of dietary habits in Chinese populations in four different geographical areas

OBJECTIVE

To compare the dietary intake of Chinese people living in Pan Yu, Hong Kong, San Francisco and Sydney with respect to cardiovascular health, using the Mediterranean diet score, examining the effects of age, gender, urbanization and acculturation on the diet score.

SUBJECTS

A total of 500 men and 510 women in Hong Kong were recruited as a territory-wide stratified random sample. Subjects were recruited in response to local advertisements for the other three sites: Pan Yu, 58 men, 95 women; San Francisco, 166 men, 192 women; Sydney, 95 men, 73 women.

METHOD

Food-frequency questionnaire over a 7 week period. A high/healthy score was taken as > or =4 for men and >3 for women, representing a dietary pattern beneficial for cardiovascular health.

RESULTS

In Hong Kong, more women in the middle age group (35-54) had a high score than other age groups, and overall more women had high scores than men. In comparing the four geographical regions, Pan Yu had the highest number of subjects with high score, and Hong Kong had the lowest. With the exception of the younger population and men in Hong Kong, the percentage of the population with a high score in all sites is greater than among elderly Greeks consuming a more traditional heart-healthy Mediterranean diet.

CONCLUSION

Considerable variations in Chinese dietary patterns exist with respect to age, gender and geographic location. Overall, the Chinese diet is comparable to the Mediterranean diet and may be expected to have similar health benefits that have been documented for the traditional Mediterranean diet.

Determination of the major isosteroidal alkaloids in bulbs of Fritillaria by high-performance liquid chromatography coupled with evaporative light scattering detection

A new direct HPLC analytical method using evaporative light scattering detection coupled with a low-temperature adapter for the simultaneous determination of the major biologically active isosteroidal alkaloids in Bulbus Fritillariae, a commonly used antitussive traditional Chinese medicinal (TCM) herb, has been developed. The simultaneous separation of eight Fritillaria alkaloids was achieved on a reversed-phase C8 column with an isocratic mobile phase system consisting of acetonitrile-methanol-water (66.5:3.5:30, v/v) containing 0.006% triethylamine. This method provides good reproducibility and sensitivity for the quantification of six major isosteroidal alkaloids, namely peimissine, verticine, verticinone, imperialine, isoverticine and ebeiedine in different Fritillaria species with overall intra- and inter-day precision and accuracy of less than 11% and higher than 90%, respectively. The assay was successfully utilized to quantify the major biologically active alkaloids in five Fritillaria species. The results demonstrate that this method is simple, selective, and suitable for the quality control of this commonly used antitussive TCM herb, Bulbus Fritillariae. reserved.

Sensitivity to Fas-mediated apoptosis is determined below receptor level in human vascular smooth muscle cells

Despite Fas expression, many cells resist Fas-induced apoptosis. Although differences in surface Fas expression can explain Fas resistance, multiple proteins below receptor level also inhibit Fas-induced apoptosis. To examine the mechanism of Fas resistance, we studied Fas-induced apoptosis in human medial vascular smooth muscle cells (VSMCs) from healthy coronary arteries. VSMCs showed marked heterogeneity to Fas-induced apoptosis, exhibiting both Fas-resistant (98.1+/-2.3% viable, n = 4, P = NS) and Fas-sensitive (31.3+/-2.6% viable, n = 3, P<0.01) cells. Fas-resistant VSMCs expressed surface Fas and could recruit RIP, indicating that functional receptor complexes were formed. However, Fas-resistant cells showed reduced expression of FADD, Fas ligand, and caspases 3, 7, and 8 and increased expression of FLIP and c-IAP-1. Fas-induced apoptosis was associated with cleavage of caspase 3 and blocked by inhibitors of caspase 3 or 8 but not caspase 1, 6, or 7. Selective inhibition of caspase 3 or 8 by antisense transfection inhibited Fas-induced apoptosis, but their reexpression could not rescue the Fas-resistant phenotype. In vivo, medial VSMCs showed marked heterogeneity of expression of caspase 3. We conclude that Fas sensitivity is determined not only by expression of surface Fas but by differential expression of Fas-signaling proteins below receptor level. Subpopulations of cells within the same tissue have different sensitivities to apoptosis, determined by expression of specific death-signaling proteins.

Case management in the Community Psychiatric Nursing Service in Hong Kong: describing the process

PURPOSE

To explore the roles, functions, and work practices of case managers and their perceptions on the implementation of case management in the Community Psychiatric Nursing Services.

METHODS

A qualitative descriptive approach was used. Data were collected from daily reports, field observations, reflective diaries, and small group interviews.

FINDINGS

The study showed the work practices of case managers were more intensive compared to the conventional community psychiatric nursing practice, and there was more involvement of clients and their family in the treatment process. Case managers identified liaison, coordination, supportive and family counseling, and teaching practical living skills as their important roles.

CONCLUSIONS

This study provides valuable information in understanding the process of case management and contributed to the development of case management as a care delivery model in Hong Kong.

Comparison of a commercial enzyme-linked immunosorbent assay with immunofluorescence and complement fixation tests for detection of Coxiella burnetii (Q fever) immunoglobulin M

A commercially available enzyme-linked immunosorbent assay (ELISA) for the diagnosis of Q fever (PanBio Coxiella burnetii immunoglobulin M [IgM] ELISA, QFM-200) was compared to the indirect fluorescent antibody test (IFAT) for C. burnetii IgM and the complement fixation test (CFT). The ELISA demonstrated 92% agreement with the reference method (IFAT), and gave a sensitivity of 99% (69 of 70 samples) and a specificity of 88% (106 of 121). Specificity can be increased with confirmation by IFAT. CFT was found to have a specificity of 90% (107 of 119), although it was lacking in sensitivity (73%; 51 of 70). No cross-reactivity was observed in the ELISA with serum samples from patients with mycoplasma (n = 6), chlamydia (n = 5), or legionella (n = 4) infections, although 2 of 5 patients with leptospirosis and 1 of 4 samples containing rheumatoid factor (RF) demonstrated positive results in the ELISA. Results indicate that the performance of the PanBio C. burnetii (Q fever) IgM ELISA (F = 187) is superior to that of CFT (F = 163), and consequently the ELISA should be a useful aid in the diagnosis of acute Q fever.

Simultaneous determination of seven major isosteroidal alkaloids in bulbs of Fritillaria by gas chromatography

The present paper describes the development of a most simple, sensitive, and specific gas chromatographic method to date, for the direct determination of seven major bioactive isosteroidal alkaloids, namely ebeiedine, ebeiedinone, ebeienine, hupehenine, isoverticine, verticine, verticinone and imperialine, in Fritillaria species, a commonly used antitussive traditional Chinese medicinal (TCM) herb. In the present study, a commercially available Supelco SAC-5 capillary column (30 m x 0.25 mm, 0.25 microm) specifically designed for the analysis of steroids was utilized for the direct determination of Fritillaria alkaloids. Calibration curves were obtained by spiking authentic compounds and the internal standard (solanidine) into herbal samples prior to extraction. Extraction was conducted simply by shaking the pre-alkalized diethyl ether solution (5.0 ml) containing dried herb (0.1 g) for 2 h. All calibration curves showed good linear regressions (r2>0.995) within test ranges. The assay was reproducible and accurate with the overall intra- and inter-day variation and accuracy of less than 10% and more than 90%, respectively. The developed GC method was successfully utilized to analyze seven major bioactive alkaloids in seven Fritillaria species, and the results demonstrate that this direct GC analytical method is suitable for the quality control of this commonly used antitussive TCM herb.

Implementing contract learning in a clinical context: report on a study

This paper reports on a study of the implementation and evaluation of learning contracts in a clinical context for a group of students who were in their third year of study in a pre-registration bachelor of nursing degree programme in Hong Kong. A learning contract was implemented as a learning tool in the students' clinical placement in mental health nursing. An action research approach was used in this study. Data were collected from questionnaires and interviews with students and clinical instructors. Results showed that students and clinical instructors generally agreed that there was an increase in students' autonomy and motivation in learning with the use of a learning contract. It also increased the sharing between students and clinical instructors. The findings of the questionnaire and interviews supported each other. However, the lack of experience in using contract learning and the limited time in the clinical areas created difficulties for both students and clinical instructors. Despite the limitations, contract learning is considered beneficial to students' learning and has the potential to be used in clinical learning.

Prior topical anesthesia reduces time to full cycloplegia in Chinese

PURPOSE

To investigate the effect of prior anesthesia on the time to full cycloplegia in young Chinese subjects.

METHODS

The amplitude of accommodation was monitored over a 50-minute interval after the application of 1% cyclopentolate hydrochloride with a pretreatment of 0.4% benoxinate (oxybuprocaine) or 0.9% saline solution (control). Using a nonlinear mathematical model, the rate of accommodative loss (k) and the time required for 95% of total cycloplegia (T95%) were determined.

RESULTS

Statistical analysis revealed a significantly faster rate of accommodative loss (P < .0001) after prior anesthesia (0.129 +/- 0.05) compared with the controls (0.103 +/- 0.04). T95% was noted at 26.43 +/- 10.22 minutes after prior anesthesia, which was significantly shorter (P < .0001) than that after the saline treatment (35.28 +/- 16.51 minutes).

CONCLUSIONS

Prior application of topical anesthetic can shorten the time to full cycloplegia for people, such as the Chinese, with dark irides.

Pre-column derivatization and gas chromatographic determination of alkaloids in bulbs of Fritillaria

A method of precolumn derivatization GC with FID detection was developed for a simultaneous analysis of five major steroidal alkaloids of Fritillaria species, namely ebeiedine, ebeiedinone, verticine, verticinone and imperialine. Derivatization was carried out by trimethylsilylation of the hydroxyl-containing Fritillaria alkaloids to the corresponding trimethylsilylates with trimethylsilylimidazole. Reaction conditions were optimised and the alkaloids derivatives were characterised by on-line GC-MS. The validated GC method demonstrated a good linearity at the sampling ranges used. This analytical method is simple, convenient and reproducible. The developed assay was successfully applied to the determination of the major pharmacologically active alkaloids in three commonly used antitussive Fritillaria species: F. cirrhosa, F. thunbergii and F. pallidiflora.

Laparoscopic exploration in the management of retroperitoneal masses

BACKGROUND AND OBJECTIVES

The isolated finding of a retroperitoneal mass (RM) often represents a diagnostic challenge. Image-guided biopsy is frequently inadequate for diagnosis. With increasing experience, the use of laparoscopy for exploration of an indeterminate RM may provide a minimally invasive alternative to open exploration. Herein, we present a retrospective review of our initial four laparoscopic explorations, comparing our experience to four contemporary open explorations for an RM.

PATIENTS AND METHODS

From July 1995 to January 1998, four patients, aged 50 to 62 years old, with an RM of undetermined etiology underwent laparoscopic exploration. Another four patients underwent open exploration at the same hospital. The medical records of these patients were reviewed.

RESULTS

The tumors were smaller in the laparoscopic group, averaging 3.7 cm (range 2-6 cm) vs 6.5 cm (range 1-10 cm) in the open group. A definitive diagnosis was obtained for all eight patients. Postoperative complications were observed in one of the laparoscopic explorations, and in three of the open explorations; there was no operative mortality. The blood loss (90 vs 440 ml), fall in hematocrit (5.1 vs 7.8%), time to resumption of a regular diet (3 vs 5 days), amount of morphine sulfate equivalents required for analgesia (128 mg vs 161 mg), time to ambulation (2.3 vs 6 days) and hospital stay (4.8 vs 6 days) were all less among the laparoscopy patients. However, the operative time was longer for the laparoscopic procedure; this time included stent placement and patient repositioning in addition to the time for laparoscopic excision of the mass (7.8 vs 4.3 hours).

CONCLUSION

Laparoscopic exploration appears to be a viable alternative to open exploration in patients presenting with a retroperitoneal mass. It is as effective as an open procedure and provides benefits with regard to patient morbidity and convalescence. However, operative time for this laparoscopic procedure is lengthy.

The use of critical pathways in caring for schizophrenic patients in a mental hospital

To provide quality health care and at the same time, to control cost, literature suggests that using critical pathways as a tool can enhance resource management, increase collaborative practice, and benefit patient care. This study describes the processes of developing a critical pathway in caring for schizophrenic patients in a mental hospital in Hong Kong. The perceived benefits and difficulties in using the critical pathway are discussed from a nursing perspective. Nurses believed that the use of critical pathways could improve the coordination and effectiveness of care. Also, nurses' autonomy and professional status improved. However, inadequate knowledge and resistance from other disciplines were barriers to the implementation. Recommendations are given to overcome the barriers.

Political participation in Hong Kong: a study

AIMS

The aim of this study was to investigate nurses' level of political participation and their perception of political efficacy.

METHODOLOGY

This is a descriptive study. A self-completed questionnaire survey was conducted. Some items in the adopted questionnaire were modified to suit the Hong Kong situation.

SAMPLES

A convenience sample was used. Three hundred and fifty registered nurses that were studying nursing degree programmes in the three universities in Hong Kong were invited to participate in the study.

FINDINGS

Three hundred and eleven registered nurses completed the questionnaire. The findings showed that there were some positive signs of both political awareness and participation in nurses. However, political activities were mainly confined to voting in general elections. Attempts to influence politicians were not evident. Subjects generally have low political efficacy, and they did not feel that nurses had the power to influence the government's policy. The results of this study are discussed in terms of the barriers to nurses' political participation and the recommendations for nursing professional development.

Human recombinant single-chain antibody fragments, specific for the hypervariable region 1 of hepatitis C virus, from immune phage-display libraries

The hypervariable region 1 (HVR1) of hepatitis C virus (HCV) may contain a potential neutralization site and the generation of human single-chain antibody fragments (scFv) to HVR1 may therefore provide a useful tool for the study of HCV. In this report, we have isolated and characterized three anti-HVR1 scFv clones from two patient-derived phage-displayed libraries and HCV HVR1 peptides. scFv S52/20 and S53/6 were selected with serologically cross-reactive HVR1 peptides. scFv p3f10 was obtained by screening the library from patient MH with an autologous HVR1 peptide. Nucleotide sequencing showed that the VH chains and Vkappa chains of all three scFv antibodies were derived from VH3 and Vkappa1 family germline V-genes, respectively. The specificity and affinity of the recombinant scFv antibodies were examined by enzyme-linked immunosorbent assay (ELISA) and an affinity biosensor, using HVR1 peptides. S52/20 scFv binding to S52 HVR1 peptide was blocked by preincubation with soluble peptide S52 and was partially competed by one of three HCV-infected patient sera. In addition, scFv S52/20 blocked the binding of HCV-susceptible Molt-4 cells to immobilized S52 peptide. This study demonstrates that recombinant human scFv antibodies to HCV HVR1 can be produced in vitro and directly confirms that HVR1 of HCV elicits highly specific antibodies. The very high specificity of these antibodies to HVR1 may limit their potential use in passive immunization therapy against HCV, and further engineering of the scFvs needs to be performed to generate broad-spectrum blocking scFvs.

The continuum-of-addiction: cigarette smoking in relation to price among Americans aged 15-29

We studied the relationship between current cigarette smoking and price among 34145 respondents, aged 15-29 years, to the 1992-1993 Tobacco Use Supplements to the Current Population Survey. The price elasticity of current smoking varied inversely with age: -0.831 (S.E. 0.402) for ages 15-17; -0.524 (S.E. 0.256) for ages 18-20; -0.370 (S.E. 0.188) for ages 21-23; -0.202 (S.E. 0.175) for ages 24-26; and -0.095 (S.E. 0.157) for ages 27-29. In response to higher prices, older youth were more likely to reduce the number of cigarettes smoked per day than to quit entirely. Among 15-17-year-olds, smoking cigarettes 'some days' was more sensitive to price than smoking 'every day'. Cigarette smoking was inversely related to the prices of premium brands, but not discount brands.

Cell surface trafficking of Fas: a rapid mechanism of p53-mediated apoptosis

p53 acts as a tumor suppressor by inducing both growth arrest and apoptosis. p53-induced apoptosis can occur without new RNA synthesis through an unknown mechanism. In human vascular smooth muscle cells, p53 activation transiently increased surface Fas (CD95) expression by transport from the Golgi complex. Golgi disruption blocked both p53-induced surface Fas expression and apoptosis. p53 also induced Fas-FADD binding and transiently sensitized cells to Fas-induced apoptosis. In contrast, lpr and gld fibroblasts were resistant to p53-induced apoptosis. Thus, p53 can mediate apoptosis through Fas transport from cytoplasmic stores.