Single-parameter charge pump in a zigzag graphene nanoribbon

We report a theoretical study of a single-parameter quantum charge pump in the clean zigzag graphene nanoribbon (ZGNR) system. By Keldysh Green's function method, we show that a pumped current in the ZGNR with an even number of zigzag chains can sharply increase from zero as the frequency matches the Fermi energy, whereas the pumped charge current is always absent in the ZGNR with an odd number of zigzag chains as well as the GNR with armchair edges, it is attributed to the peculiar zero-energy edge state in the ZGNR and the symmetry breaking of the topologically inequivalent carbon atoms due to the zigzag edges. The pumped current in the even-ZGNR decreases with the Fermi energy and its direction is determined by Fermi energy below or above the Dirac point as well as the type of carbon atoms at one edge of the ZGNR. The two-parameter charge pump in the ZGNR is also discussed and the magnitude of the pumped current is comparable to the single-parameter pump when the pumping frequency matches the Fermi energy.

Josephson current oscillation in a Rashba ring

We propose to use Rashba spin-orbital coupling (RSOC) to modulate the Josephson current in a one-dimensional ring-SQUID (superconducting quantum interference device) without any magnetic field or magnetic material. Supercurrent oscillation due to spin-dependent quantum interference of spin wavefunctions passing through the two arms of the ring in the presence of RSOC is found. A pure spin current flows in the system's ground state without a supercurrent due to the combined effect of the RSOC precession phase and the electron traveling phase caused by the asymmetry in the two arms of the ring. This purely electrical means of modulating the supercurrent by varying the RSOC will be useful for designing novel superconductor devices.

Imaging of STAT3 signaling pathway during mouse embryonic stem cell differentiation

Signal transducers and activators of transcription 3 (STAT3) is a pleiotropic transcription factor involved in a variety of physiological processes. STAT3 acts as a key transcriptional determinant of mouse embryonic stem (ES) cell self-renewal and plays a pivotal function in early mammalian embryogenesis because the development of many organs requires STAT3 activation. However, little is known about the role of STAT3 function during ES cell differentiation. To answer this question, we built a lentiviral construct with 7-repeat STAT3-binding sequence (enhancer) and minimal TA (promoter) driving renilla luciferase and monomeric red fluorescence protein (Rluc-mRFP), followed by a constitutive cytomegalovirus promoter driving green fluorescent protein as a selection marker. The specificity of our custom-designed 7-repeat STAT3 reporter construct was first confirmed by cotransfection with constitutively active version of STAT3 (STAT3C) into human embryonic kidney 293T cells. Next, a mouse ES cell line stably transduced with STAT3 reporter construct was isolated. This ES cell line showed a tight response in reporter gene expression with leukemia inhibitory factor (LIF) induction and was chosen as a developmental model for the STAT3 functional study. Using serial noninvasive bioluminescence imaging, we showed that the onset of embryoid body (EB) formation involved inhibition of STAT3 activity. However, during differentiation, STAT3 activity steadily increased from day 5 to 14 and was reduced by day 21. STAT3 activity was also confirmed separately by Western blots. Finally, phosphorylation of STAT3 was also found to correspond with cardiomyocyte differentiation. In summary, this is the first study to monitor real-time STAT3 activity during ES cell differentiation. This genetically modified line can be used to study the biological role of STAT3 during ES cell differentiation into different derivatives.

Spin density induced by equilibrium spin current in a magnetic field

We propose theoretically to use an external magnetic field to detect the equilibrium spin current which flows in a narrow strip. The spin current is generated by two noncollinear ferromagnets attached to the strip and the applied magnetic field is perpendicular to the plane of the strip. It is demonstrated by using the Keldysh Green's function that the interaction between the spin current and the magnetic field causes an antisymmetrical spin density at the two lateral edges of the strip. The spin density can be directly measured experimentally. Its magnitude and direction can be readily controlled by the magnetizations of the ferromagnets. The proposed scheme offers a new approach to the detection of the pure spin current.

An empirical study of characteristics and types of homicide-suicides in Hong Kong, 1989-2005

BACKGROUND

Clinical classification of types of homicide-suicide (HS) was proposed, but no information on empirical-based classification and prevalence of different types of HS was available. This paper aimed to empirically classify HS events into different clusters and to discuss specific evidence-based prevention initiatives.

METHOD

Data of HS offenders from Coroner's Court were analyzed through a two-step cluster analysis. Number of clusters and appropriate allocations of cases were obtained. External background variables were tested through post hoc tests to explore the differences among clusters.

RESULTS

Two hundred and thirty-one people died in 98 episodes in the study period (1989-2005). The majority of HS offenders were male (n=68, 68.7%) and aged 30-49 (n=62, 62.6%). Domestic killing was the major type of HS in which over 60% of the homicide motivation was related to spousal conflicts or altruistic reasons. Spouses (n=46, 46.5%) and children (n=47, 47.5%) were predominantly the victims. The common killing methods included chopping with weapons (n=33, 33.3%) and charcoal burning (n=22, 22.2%). Six clusters of HS were derived from the cluster analysis and were further reduced to four major classes. Four major classes were dispute, conflicts in a relationship, altruistic, and mental illness. These classes could be differentiated by methods of homicide and suicide, gender of perpetrator, relationship with victim, and indebtedness.

CONCLUSIONS

Financial problem, dispute and domestic violence are significant precipitants of HS in Hong Kong. Those people associated with the precipitating factors should be the targets for intervention and prevention.

Follicular dendritic cell sarcoma of inguinal lymph node--a case report

Follicular dendritic cell sarcomas (FDCS) are rare neoplasms that involve lymph nodes or extranodal sites. They show varied histological features and thus can be mistaken for carcinoma or sarcoma. Correct identification is important for further management. A 43-year-old Indian female presented with a three-month history of progressive swelling at the right inguinal region. It was excised completely and was reported as lymph node with metastatic poorly differentiated carcinoma based on Haematoxylin and eosin (H&E) stain findings. Computerized tomography (CT) scans of thorax, abdomen and pelvis were normal and did not reveal a primary site. Following this, the case was referred to one of the authors. The slides were reviewed and a variety of immunocytochemical markers were done. The tumour cells were negative for epithelial, melanocytic, neural, leucocyte and soft tissue tumour markers. They were immunopositive for CD21, CD35 and negative for CD68. Based on the immunocytochemical findings, a final diagnosis of FDCS was made. This case highlights the histological and immunophenotypical profile of a rare tumour which requires a high index of suspicion for diagnosis.

Conductance oscillations in a nanowire double junction

The interaction between two nanowire cross-junctions is studied in a three-wire double-junction structure. The dc conductances between terminals in the double-junction structure are calculated from the Green's function, which is obtained using the modular Green's function approach. Significant oscillations are found in the inter-wire conductances in both junctions, which are the consequence of interference of electron waves reflected between junctions. A phenomenological expression, which can relate the positions of neighboring oscillation peaks, is developed based on the interference mechanism. The interaction between quasi-bound states formed at the junctions is found to be negligible and has no significant effect on the inter-wire conductance peaks. Our results show that interaction between neighboring junctions should be properly considered in the modeling and design of nanowire devices and circuits.

Abstract 4998: Molecular profiling reveals heterogeneity of active self-renewal pathways in bladder cancer stem cells

The objective of the current study is to investigate the functional involvement of self-renewal related genes in patient bladder cancer stem cells. First, by fractionating primary patient bladder transitional cell carcinomas (TCCs) into subpopulations with flow cytometry, a unique tumor-initiating subpopulation expressing CD44 was identified in 5 independent TCCs, based on their enriched potential (10-200 folds) to induce xenograft tumors in immunocompromised mice. To extend this finding to a larger sample set, we analyzed a tissue array containing more than 300 bladder TCCs by immunohistochemistry. Approximately 40.4% of TCCs contain CD44+ cells; these cells usually express cytokeratin 5 (CK5) (P<0.0001) but not cytokeratin 20 (P=0.8160). In addition, cellular morphologies of CD44+ tumor cells are often small and round shape. These data suggest that CD44+ tumor cells retain cytokeratin markers and cellular morphologies resembling that of urothelial basal cells. Further, molecular profiling of oncogenic proteins implicated in the self-renewal of stem cells (i.e. Bmi1, Stat3, ß-catenin, Gli1, Oct4 and Nanog) revealed heterogeneity in bladder TCCs. Different subsets of CD44+ bladder TCCs express either one or more of different self-renewal proteins in their active forms (i.e. ~10% with nuclear Bmi1, 30% with nuclear Stat3, 5% with nuclear ß-catenin, 85% with active Gli1 and 0% with active Oct4 nor Nanog). In particular, in situ hybridization demonstrated that Gli1 mRNA was present in over 85% of bladder TCC specimens analyzed. Therefore, we examined the functional significance of the sonic hedgehog pathway in bladder tumor development. In patient bladder xenografts that originally contained active Gli1 in the cancer stem cells, preliminary experiment demonstrated that inhibition of this pathway with cyclopamine resulted in partial reduction of tumor volume (4 out of 6 xenografts). Previous reports demonstrated that genetic mutations in the pathway components (i.e. PTCH or Gli1) leading to constitutive Gli1 activation is rare in bladder TCCs. Preliminary microRNA (miRs) profiling of CD44+ bladder cancer stem cells using a real-time PCR based approach revealed a panel of differentially expressed miRs. Interestingly, in several highly elevated miRs in CD44+ bladder cancer stem cells, the negative regulators of the Gli1 pathways (i.e. PTCH and SUFU) are among the top predicted targets for these miRs. Further experiments are ongoing to validate the possible involvement of miRs in regulating the Gli1 pathways in bladder cancer stem cells. In conclusion, we demonstrated the existence of a functionally unique, CD44+ tumorigenic subpopulation in a subset of bladder TCCs. Diverse “self-renewal” proteins, including Gli1, possibly contribute to the tumorigenic properties of cancer stem cells in different subset of patient bladder TCCs.

Real time mass flow rate measurement using multiple fan beam optical tomography

This paper presents the implementing multiple fan beam projection technique using optical fibre sensors for a tomography system. From the dynamic experiment of solid/gas flow using plastic beads in a gravity flow rig, the designed optical fibre sensors are reliable in measuring the mass flow rate below 40% of flow. Another important matter that has been discussed is the image processing rate or IPR. Generally, the applied image reconstruction algorithms, the construction of the sensor and also the designed software are considered to be reliable and suitable to perform real-time image reconstruction and mass flow rate measurements.

Signal transducer and activator of transcription 3 (Stat3) in epithelial carcinogenesis

Signal transducer and activator of transcription 3 (Stat3) is one of a family of cytoplasmic proteins that participate in normal cellular responses to cytokines and growth factors as transcription factors. Stat3 modulates various physiological functions including cell survival, cell-cycle regulation, and angiogenesis through regulation of gene expression, and its constitutive activation is associated with a number of human epithelial cancers. Recent studies with skin-specific gain and loss of Stat3 function transgenic mice have shown that Stat3 plays critical roles in skin carcinogenesis. Multistage skin carcinogenesis bioassays performed with these transgenic mice clearly demonstrate that Stat3 is required for both tumor initiation and promotion through regulation of genes involved in survival and proliferation, respectively. Stat3 also plays a role in malignant progression of skin tumors by regulating genes that are involved in angiogenesis and invasion. Further studies have revealed that Stat3 plays a critical role in epidermal cell proliferation and survival following exposure to ultraviolet B (UVB) irradiation. In addition, Stat3 is constitutively active in UVB-induced skin tumors from both mice and humans. Collectively, these studies suggest that Stat3 may be a potential target for both the prevention and treatment of human epithelial cancers including skin cancer.

Forced expression of a constitutively active form of Stat3 in mouse epidermis enhances malignant progression of skin tumors induced by two-stage carcinogenesis

Recently, our laboratory demonstrated that Stat3 is required for the de novo development of chemically-induced skin tumors. We have further investigated the role of Stat3 in epithelial carcinogenesis using mice in which the expression of a constitutively active/dimerized form of Stat3 (Stat3C) is targeted to the proliferative compartment of epidermis (referred to as K5.Stat3C transgenic mice). Keratinocytes from K5.Stat3C mice showed increased survival following exposure to 7,12-dimethylbenz[a]anthracene (DMBA) and enhanced proliferation following exposure to 12-O-tetradecanoylphorbol-13-acetate (TPA). In two-stage chemical carcinogenesis experiments using DMBA as the tumor initiator and TPA as the promoter, K5.Stat3C mice developed skin tumors with a shorter latency and in much greater number compared to non-transgenic littermates. Remarkably, 100% of the skin tumors that developed in K5.Stat3C transgenic mice bypassed the premalignant stage and were initially diagnosed as carcinoma in situ which rapidly progressed to squamous cell carcinoma (SCC). These tumors were highly vascularized, poorly differentiated and invasive and loss of expression of K10, filaggrin and E-cadherin was observed by 20 weeks. Finally, overexpression of Stat3C in a papilloma cell line led to enhanced cell migration and enhanced invasion through Matrigel in both the absence and presence of growth factors. In addition to its critical role in early stages of epithelial carcinogenesis, the current study reveals a novel role for Stat3 in driving malignant progression of skin tumors in vivo.

The impact of palliative care on cancer deaths in Hong Kong: a retrospective study of 494 cancer deaths

OBJECTIVES

To study the utilization of public health care by advanced cancer patients in their last 6 months of life and their end-of-life process within the last 2 weeks of life.

METHODS

This was a retrospective study on 494 cancer deaths from four public hospitals in 2005. This sample was selected from all in-patient cancer deaths by the ratio of one in four. Data were collected by review of charts and an electronic data base.

RESULTS

A total of 494 cancer deaths were analysed. The mean age of all cancer patients (n = 494) was 72.6 years. Two-thirds of cancer patients received palliative care and half died in palliative care setting. Patients were categorized into three groups according to palliative care coverage and the place of death. The first group comprised of patients who received palliative care service and died in palliative care units (PCS-PCD group, n = 247); the second group of patients who received palliative care service within the last 6 months of life but died in non-palliative care wards (n = 86); and the third group of patients who never received palliative care and who died in non-palliative care wards (NPCS-NPCD group, n = 161). Differences among groups were tested by one way ANOVA. During the last 6 months of life, patients in the PCS-PCD group had less admission to acute care wards (P = 0.012), shorter duration of stay in acute care wards (P = 0.003), and less admission to an intensive care unit setting (P < 0.001). Within the last 2 weeks of life, the PCS-PCD group had fewer interventions initiated (P < 0.001); had higher number of symptoms documented in patient's record (P < 0.001); and were more likely to receive analgesics (P < 0.001), adjuvant analgesics (P < 0.001) and sedatives (P < 0.001). Patients in PCS-PCD group were more physically dependent in the last 2 weeks of life (P < 0.001), but mentally more alert at 72 hours before death (P < 0.001). Patients in the NPCS-NPCD group had fewer patients with a do not resuscitate order present (P < 0.001), and more patients with cardiopulmonary resuscitation performed (P < 0.001).

CONCLUSION

Our results suggest that palliative care service has played a role in improving end-of-life cancer care in Hong Kong.

Determinants of chronic obstructive pulmonary disease in Chinese patients in Hong Kong

BACKGROUND

The prevalence of chronic obstructive pulmonary disease (COPD) is rising in many parts of the world. This is a study of risk factors for COPD in Chinese patients in Hong Kong.

DESIGN

Case-control study matched by sex and age (+/-5 years).

METHODS

A total of 289 consecutive patients with COPD were recruited from out-patient clinics while healthy controls were recruited from two sources: random population and community centres for senior citizens. All patients and controls underwent a questionnaire-based interview and spirometry.

RESULTS

The mean ages of COPD patients and controls were 71.1 +/- 9.4 and 67.5 +/- 9.3 years, respectively. The male to female ratio of COPD patients was 5 to 1. Smoking was found to be the most important determinant for COPD, followed by poor education and low body mass index adjusted for confounders. A dose-dependent relationship was found between the risk of COPD and pack-years smoked. Place of birth, exposure to environmental tobacco smoke and a history of asthma and tuberculosis were not associated with increased risk of COPD.

CONCLUSION

Despite a progressive reduction in prevalence, smoking remains the most important predictor of COPD in Hong Kong. Greater anti-smoking efforts are warranted.

Application of two-dimensional spectral surface plasmon resonance to imaging of pressure distribution in elastohydrodynamic lubricant films

What we believe to be a novel two-dimensional spectral surface plasmon resonance imaging technique determining pressure distribution in elastohydrodynamic lubricant films is presented. This technique makes use of the spectral characteristics associated with the surface plasmon resonance (SPR) effect, and it provides more spectral information in refractive index mapping than conventional contrast SPR imaging. Two-dimensional imaging is demonstrated and applied to a highly pressurized liquid lubricant trapped inside an elastohydrodynamic lubrication (EHL) dimple. The hydrostatic pressure inside the EHL dimple causes a localized change of the refractive index of the lubrication oil. This also results in a shift in the spectral SPR absorption dip. By monitoring the color changes within the SPR image and calibrating with lubricants of known refractive index profiles, we can obtain a direct measurement of the refractive index distribution within the EHL dimple. PB 2400 lubricant dimples were studied in our experiments. The proposed SPR imaging approach is irrespective of the absolute lubricant film thickness h, therefore overcoming the major limitations of a conventional optical interference technique. With further development of the two-dimensional refractive index mapping technique, widespread applications in various fields are possible, including high-throughput sensors and the detection of bioaffinity interactions.

Reliability, Validity, and Responsiveness of a 2-Min Walk Test To Assess Exercise Capacity of COPD Patients

PURPOSES

To investigate the reliability, validity, and responsiveness of a 2-min walk test (2MWT) in Chinese COPD patients with moderate-to-severe disease.

METHODS

This study consisted of two parts. Forty-seven stable COPD patients with moderate-to-severe disease participated in the first part of study for the investigation of reliability and validity. The demographic and anthropomorphic data collected included age, gender, body weight, height, and body mass index. Each subject performed a pulmonary function test, a cardiopulmonary exercise test, three trials of a 2MWT, and two trials of 6-min-walk test (6MWT) in random order within a 5-day period. Fifteen of these subjects participated in the second part of study for the evaluation of the responsiveness of the 2MWT following pulmonary rehabilitation. The 2MWT and 6MWT were conducted before and after the program for comparison.

RESULTS

Forty-five subjects (mean [+/- SD] age, 71.8 +/- 8.3 years; mean FEV1, 0.88 +/- 0.27 L) completed the first part of study, and 9 subjects (mean age, 74 +/- 8.7 years; mean FEV1, 0.94 +/- 0.28 L) completed the second part of study. The intraclass correlation coefficient of the repeated 2MWTs was high (R = 0.9994; p < 0.05), mean differences across trials ranged from 0.3 to 0.8 m (95% confidence interval, -3.1 to 4.6 m) demonstrated its high test-retest reliability. Significant correlations were found between the 2MWT and the 6MWT, the maximum oxygen uptake (V(O2)max) in milliliters per minute, and the V(O2)max in milliliters per kilogram per minute (r = 0.937, 0.454, and 0.555 respectively; p < 0.0125). Following rehabilitation, there were significant improvements in the mean 2MWT and 6MWT walking distance of 17.2 +/- 13.8 m and 60.6 +/- 35.5 m, respectively, with moderate effect sizes (0.61 and 0.53, respectively) and large standardized mean responses (1.25 and 1.70, respectively). High correlation was found between changes in the 2MWT and the 6MWT (r = 0.70; p < 0.05).

CONCLUSION

The 2MWT was shown to be a reliable and valid test for the assessment of exercise capacity and responsive following rehabilitation in patients with moderate-to-severe COPD. It is practical, simple, and well-tolerated by patients with severe COPD symptoms.

Computed tomography features of spontaneously perforated pyometra: a case report

Spontaneous perforation of pyometra is an extremely rare emergent gynecologic disease. We report a 73-year-old woman with a spontaneously perforated pyometra presenting with acute abdomen in the emergency department. A dedicated computed tomography examination of the abdominal and pelvic regions revealed the diagnosis. The patient recovered well after surgical intervention and antibiotic treatment.

[Matrix metalloproteinases and their inhibitors in lung cancer with malignant pleural effusion]

Matrix metalloproteinases (MMP) and tissue inhibitors of metalloproteinases (TIMP) play a crucial role in physiological and pathological matrix turnover. This study aimed to determine the occurrence of MMP and TIMP in lung cancer patients with malignant pleural effusions (CA).

METHODS

MMP-1, MMP-2, MMP-3, MMP-8, MMP-9, TIMP-1, and IMP-2 oncentrations were determined by ELISA and zymography in pleural effusions and plasma of 31 CA and 14 congestive heart failure (CHF) patients and in plasma of 18 healthy controls (CON).

RESULTS

MMP-2, TIMP-1, and TIMP-2 ELISA-concentrations were increased in CA pleural fluid vs. CA plasma (p < 0.005, p < 0.005, p < 0.05), in contrast to MMP-9 being higher in plasma (p < 0.005). Pleural fluid MMP-1 and MMP-8 were increased in CA vs. CHF (p < 0.05, p < 0.005). MMP and TIMP plasma concentrations were not different in CA vs. CHF, but MMP-9, TIMP-1, and TIMP-2 were increased vs. CON (p < 0.005, each). Gelatine zymography MMP-9/MMP-2 ratios were increased in CA plasma vs. effusion fluid (p < 0.005), in CA vs. CHF plasma, CA vs. CHF effusions (p < 0.005 each), and in CA vs. CON plasma (p < 0.05).

CONCLUSIONS

MMP-2, TIMP-1, and TIMP-2 accumulate in the pleural compartment in CA and CHF, probably reflecting an unspecific pleural reaction. MMP-1 and MMP-8 are increased in cellular rich CA pleural effusions only. The determination of MMP-9/MMP-2 ratios in pleural fluid may contribute to differentiate CHF from CA effusions.

Ab Initio and Variational Transition State Approach to β-C3N4 Formation: Kinetics for the Reaction of CH3NH2 with H

The CH3NH2 molecule has been considered as either an important intermediate in methane and ammonia mixtures or a precursor in methylamine and hydrogen mixtures in the synthesis of carbon nitride thin films. The fast Hydrogen (H) abstraction from CH3NH2 is an important process involved in the formation of HCN or CNH in the chemical vapor deposition (CVD) of carbon nitride thin films. The energetic and kinetic characteristics of the H abstraction reaction from CH3NH2 by atomic H used in CVD of beta-C3N4 were studied using ab initio direct dynamics methods for the first time. Two primary processes were identified for this reaction: H abstraction from the CH3 group and H abstraction from the NH2 group. On the basis of ab initio data, the rate constants of each channel have been deduced by canonical variational transition state theory with small-curvature tunneling correction over a wide temperature range of 200 to approximately 3000 K. The theoretical results were compared with available experimental data.

Duration of RT-PCR positivity in severe acute respiratory syndrome

Severe acute respiratory syndrome (SARS) is a highly infectious respiratory infection with a high mortality. The duration of infectivity is unknown. The RT-PCR positivity for SARS-associated coronavirus (SARS-CoV) was followed in 45 virologically confirmed SARS patients. Serial RT-PCRs for SARS-CoV were performed in the nasopharyngeal aspirate, stool and urine of 45 SARS patients who survived until discharge. All patients had at least one site that was positive for SARS-CoV on presentation. Time to RT-PCR conversion was studied in all patients. There were 15 males (33.3%) and 30 females (66.7%), with a mean+/- SD age of 40.7+/-14.7 yrs. The median (range) time of RT-PCR conversion was 30 days (2-81). On discharge from the hospital, 18 (40%) remained RT-PCR positive in at least one site. For patients with positive RT-PCR on discharge, the median (range) time to RT-PCR conversion after discharge was 13 days (2-60). A significant proportion of severe acute respiratory syndrome patients remained RT-PCR positive for severe acute respiratory syndrome-associated coronavirus for a substantial duration after discharge. The clinical significance is unknown and this finding merits further study. It is prudent to advise patients to adhere to strict personal hygiene on discharge until RT-PCR becomes negative.

Vascular endothelial growth factor in pleural effusions of different origin

This study aimed to determine the diagnostic relevance of vascular endothelial growth factor (VEGF) in the pleural fluid and serum of patients with pleural effusions of different aetiology. VEGF was quantified in the pleural effusion fluid and serum of 96 patients with malignancies (58 lung cancers (CA) and 38 tumours with secondaries to the lung (TM)), 45 with congestive heart failure (CHF), 28 with tuberculosis (TB), 45 with acute infections (INF), and in the serum of 20 healthy controls. VEGF pleural effusion concentrations were significantly different in the main diagnostic groups. VEGF was higher in effusions of patients with malignancies (CA as well as TM) in comparison with INF, TB or CHF. In serum, however, high VEGF concentrations indicated CA, TM or INF, but not TB or CHF. Despite significant differences of VEGF levels in different patient groups, receiver-operating characteristic analysis revealed insufficient diagnostic value of VEGF for differential diagnosis of pleural effusions. In conclusion, vascular endothelial growth factor serum concentration is highly suggestive of the presence of lung disease in general, except for tuberculosis. In effusion fluid, the presence of vascular endothelial growth factor clearly indicates inflammatory or malignant origin. However, for diagnostic use, additional parameters besides vascular endothelial growth factor are mandatory.

Spontaneous pneumomediastinum in patients with severe acute respiratory syndrome

Spontaneous pneumomediastinum (SP) unrelated to assisted ventilation is a newly recognised complication of severe acute respiratory syndrome (SARS). The objective of the present study was to examine the incidence, risk factors and the outcomes of SP in a cohort of SARS victims from a community outbreak. Data were retrieved from a prospectively collected database of virologically confirmed SARS patients. One hundred and twelve cases were analysable, with 13 patients developing SP (11.6%) at a mean +/- SD of 19.6 +/- 4.6 days from symptom onset. Peak lactate dehydrogenase level was associated with the development of SP. SP was associated with increased intubation and a trend towards death. Drainage was required in five cases. For patients who survived, the SP and/or the associated pneumothoraces took a median of 28 days (interquartile range: 15-45 days) to resolve completely. In conclusion, spontaneous pneumomediastinum appeared to be a frequent complication of severe acute respiratory syndrome. Further research is needed to investigate its pathogenesis.

[Immunohistochemical localization of matrix metalloproteinases (MMP) and tissue inhibitors of metalloproteinases (TIMP) in tuberculous pleuritis]

Matrix metalloproteinases (MMP) and tissue inhibitors of metalloproteinases (TIMP) have been found by ELISA and gelatine zymography in different concentrations in pleural fluid in tuberculous (TB) pleuritis. For further differentiation MMP and TIMP were localized in pleural biopsies by immunhistochemical staining with antibodies directed against MMP-1, MMP-2, MMP-3, MMP-9, TIMP-1, and TIMP-2 using the Labelled-Avidin-Biotin (LAB). Immunohistological reactivity of MMP-1 was found in epitheloidcellular histiocytes, Langhans' giant cells, lymphocytes, macrophages, as well as in fibroblasts of granulomatous reactions. MMP-2 was found in a few epitheloid cellular histiocytes, fibroblasts, and inflammatory cells. MMP-3 was weakly positive in a few lymphocytes only. MMP-9 was found in a few fibroblasts, epitheloid cells, and inflammatory cells, foremost, however, in pleural mesothial cells. A few fibroblasts only showed immunoreactivity of TIMP-1 and TIMP-2. The observed inhomogenous staining pattern could be explained by the different state of activation of individual cellular units. In conclusion, the immunohistochemical demonstration of MMP and TIMP in pleural cells and tissue structures indicates their local involvement in fibrosing reactions in TB-pleuritis.

[Pleuritis tuberculosa - therapeutic value of repeated chest tapping]

Tuberculous pleuritis tends to develop fibrosis to a high degree. The use of corticosteroids enhances the absorption of pleural effusions, the residual pleural thickening, however, remains unaffected. Whether repeated chest tapping in patients with persistent effusions in addition to antituberculous therapy favourably influences the outcome is not known. Therefore, patients with tuberculous pleuritis were examined in a prospective, randomized study. After confirmation of the diagnosis patients were randomized in group A with antituberculous treatment (Isoniazid, Rifampicin, Pyrazinamid, and Streptomycin) alone or in group B with additional pleural tapping for four weeks (phase I). In phase II patients in both groups with persistent effusions received oral prednisolone (0,75 mg/kg body weight) tapered over four weeks. The extent of pleural effusions was determined by chest X-ray. Roentgenological changes were evaluated at the end of the observation period. Lung function tests by spirometry were performed after two, four, eight weeks, and at the last follow up visit. At the end of phase I no pleural effusion could be observed roentgenologically in group A in 7 of 16 patients (44 %) and in group B in 10 of 16 patients (63 %) (p = n. s.). At the end of phase II extensive residual thickening was observed in one patient (group B) necessitating pleurectomy six months later. The lung function parameters demonstrated a restrictive pattern, which did not differ significantly at the end of the observation period. After a mean follow-up period of four months none or minimal residual changes could be observed radiologically in the remaining patients. In summary, despite the low number of patients examined, this study shows that in patients with tuberculous pleuritis repeated chest tapping in addition to antituberculous medication does not seem to benefit the patient, as neither the degree of residual pleural thickening nor the restrictive lung function impairment seem to be influenced significantly.

Role of lopinavir/ritonavir in the treatment of SARS: initial virological and clinical findings

BACKGROUND

The clinical response of patients with severe acute respiratory syndrome (SARS) to a combination of lopinavir/ritonavir and ribavirin was examined after establishing the in vitro antiviral susceptibility of the SARS associated coronavirus to a panel of antiviral agents.

METHODS

The in vitro susceptibility of the prototype of SARS associated coronavirus to a panel of nucleoside analogues and protease inhibitors currently licensed for clinical use was studied. Forty one patients with SARS followed for 3 weeks were treated with a combination of lopinavir/ritonavir and ribavirin. The clinical progress and virological outcomes were monitored and compared with 111 patients treated with ribavirin only who served as historical controls.

RESULTS

In vitro antiviral activity against SARS associated coronavirus was demonstrated for lopinavir and ribavirin at concentrations of 4 micro g/ml and 50 micro g/ml, respectively, only at 48 hours. The adverse clinical outcome (ARDS or death) was significantly lower in the treatment group than in the historical controls (2.4% v 28.8%, p<0.001) at day 21 after the onset of symptoms. The adverse outcome remained significantly lower in the treatment group than in the controls-both those diagnosed early (p<0.001) and those diagnosed later in the course of the epidemic (p = 0.002)-but there was no significant difference in adverse outcome rates between the two time periods (p = 0.548). No time related difference in outcome was observed in the control groups. A reduction in steroid usage and nosocomial infections was seen in patients initially treated with lopinavir/ritonavir, and these patients had a decreasing viral load and rising peripheral lymphocyte count. Multivariate analysis showed that age, hepatitis B carrier status, and lack of treatment with this antiviral combination were independent predictors of an adverse outcome. Lopinavir/ritonavir treatment was associated with a better outcome even when adjusted for baseline lactate dehydrogenase level.

CONCLUSIONS

The apparent favourable clinical response with lopinavir/ritonavir and ribavirin supports further randomised placebo controlled trials in patients with SARS.