Solar background noise mitigation using the orbital angular momentum mode in vertical FSO downlink transmissions

Free-space optical communication (FSO) is used to provide network configuration flexibility. A network-flying platform-based vertical FSO connection can be employed to enhance mobile network coverage and capacity. Solar background noise can be a potential risk that disrupts the seamless connection in the vertical FSO downlink channel. In this paper, we propose signal transmission using an orbital angular momentum (OAM) beam. The OAM demodulation process can filter sunlight out of the optical receiver except for the signal corresponding to the azimuthal state. We experimentally verified that most of the solar background noise could be reduced. To verify the feasibility of the proposed scheme in a vertical FSO channel, we modeled a FSO vertical downlink with an OAM modulation/demodulation process.

Multidrug-resistant tuberculosis over 20 years at a referral hospital in South Korea: trends and outcomes

SETTING

A referral centre in South Korea.

OBJECTIVE

To investigate trends in drug resistance, treatment modalities and outcomes, and adverse events of multidrug-resistant tuberculosis (MDR-TB) over two decades.

DESIGN

MDR-TB patients treated at Seoul National Hospital University between 1996 and 2015 were divided into four 5-year cohorts according to the date of initial diagnosis. Changes in demographic characteristics, drug resistance, drugs used, treatment outcomes and adverse events over time were elucidated.

RESULTS

Between 1996 and 2015, 418 patients were treated for MDR-TB: 86 patients between 1996 and 2000, 125 between 2001 and 2005, 123 between 2006 and 2010, and 84 between 2011 and 2015. The proportion of patients with positive acid-fast bacilli sputum (60.5-29.7%, P < 0.001) or cavities on chest radiographs (86.0-40.5%, P < 0.001) decreased over time. Resistance to pyrazinamide, fluoroquinolones, cycloserine and p-aminosalicylic acid decreased. Later-generation fluoroquinolones (77.9-90.5%) and linezolid (0-26.2%) became more frequently prescribed. The treatment success rate increased (45.3-88.1%, P < 0.001); neurological adverse events, including peripheral neuropathy also increased (4.7-13.1%, P = 0.027).

CONCLUSION

MDR-TB patients presented with less severe disease and better resistance profiles over time in South Korea, with treatment outcomes improving continuously.

Rapidly Progressive Lactic Acidosis in Patients with Flufenoxuron Poisoning

Flufenoxuron is an insect growth regulator which inhibits chitin (exoskeleton) biosynthesis in insect's body. Not much is known about its toxicity to human. This report describes three patients who developed worsening lactic acidosis and hypotension after ingestion of flufenoxuron-containing materials. Two of the three patients received continuous renal replacement therapy and survived. (Hong Kong j.emerg.med. 2014;21:181-184)

Evaluation of Xpert(®) MTB/RIF assay: diagnosis and treatment outcomes in rifampicin-resistant tuberculosis

SETTING

The Xpert(®) MTB/RIF assay is endorsed by the World Health Organization for the detection of rifampicin (RMP) resistant tuberculosis (TB).

OBJECTIVE

To evaluate Xpert for its diagnostic accuracy in detecting RMP-resistant TB and its impact on treatment outcomes.

DESIGN

Patients with available phenotypic drug susceptibility testing (DST) results and those in whom RMP-resistant pulmonary TB was diagnosed using Xpert were evaluated. The accuracy and turnaround time (TAT) of Xpert for determining RMP-resistant TB was calculated. The TATs for treatment between patients diagnosed with RMP-resistant TB using Xpert and those diagnosed without the assay (phenotypic DST group) were compared.

RESULTS

In 321 patients, when phenotypic DST was used as the gold standard, Xpert sensitivity and specificity for RMP resistance diagnosis was respectively 100% and 98.7%; the positive and negative predictive values were respectively 86.2% and 100%. The Xpert group had a much shorter interval from initial evaluation to commencing second-line anti-tuberculosis treatment (64 vs. 2 days, P < 0.001), and negative conversion of mycobacterial cultures (197 vs. 62.5 days, P < 0.001) than the phenotypic DST group.

CONCLUSION

Xpert was accurate at diagnosing RMP resistance in this setting with an intermediate TB burden and a low level of RMP resistance. Xpert might reduce disease transmission by reducing the sputum culture conversion times for patients with RMP-resistant TB.

Changes in treatment outcomes of multidrug-resistant tuberculosis

SETTING

After several changes in treatment modalities, it is time to re-evaluate treatment outcomes of multidrug-resistant tuberculosis (MDR-TB).

OBJECTIVE

To evaluate treatment outcomes, elucidate changes in outcomes over time and identify predictors of treatment success for MDR-TB.

DESIGN

Patients diagnosed with MDR-TB at a tertiary referral centre in South Korea between January 2006 and December 2010 were included. Treatment modalities and outcomes were assessed. Predictors of treatment success were analysed using multiple logistic regression. The treatment modalities and outcomes of these patients were compared with those of MDR-TB patients between January 1996 and December 2005.

RESULTS

Of the 123 MDR-TB patients diagnosed during the later study period, treatment was successful in 103 (83.7%). Extensive drug resistance (OR 0.31, P = 0.044) and additional resistance to fluoroquinolones (OR 0.23, P = 0.039) were inversely associated with treatment success. The treatment success rate improved from 53.5% in 1996-2000 to 68.8% in 2001-2005 and 83.7% in 2006-2010 (P < 0.001). Improved outcomes were accompanied with more frequent use of later-generation fluoroquinolones and linezolid and less frequent surgical resection.

CONCLUSION

Treatment outcomes for MDR-TB improved at a tertiary referral centre in South Korea. The improvement was associated with more frequent use of later-generation fluoroquinolones and linezolid.

Effect of inhalers on the development of haemoptysis in patients with non-cystic fibrosis bronchiectasis

BACKGROUND

The association of inhaler use with haemoptysis has rarely been reported in patients with non-cystic fibrosis (CF) bronchiectasis.

OBJECTIVE

To elucidate the effect of inhaler use on the development of haemoptysis in patients with non-CF bronchiectasis.

METHODS

In a case-crossover study of 192 non-CF bronchiectasis patients with a history of haemoptysis and inhaler use, the risk of haemoptysis associated with the use of inhalers was elucidated. Two inhaled corticosteroids/long-acting β₂-agonists (ICS/LABA), one long-acting muscarinic antagonist and one short-acting β₂-agonist (SABA) were evaluated. The case and control periods were defined respectively as 030 and 180210 days before haemoptysis.

RESULTS

The risk of haemoptysis during the case period was 3.51 times higher than during the control period with any use of inhalers (95%CI 1.966.28). The results of clinically significant haemoptysis showed good agreement with those of total events. These associations were consistent with the sensitivity analyses. In the sub-analysis according to inhaler type, ICS/LABA and SABA were significantly associated with an increased risk of haemoptysis (aOR 2.62, 95%CI 1.255.45; aOR 2.51, 95%CI 2.235.15).

CONCLUSIONS

In patients with non-CF bronchiectasis, the use of inhalers, especially including 2-agonist, was associated with an increased risk of haemoptysis.

Accuracy of the Xpert® MTB/RIF assay for the diagnosis of extra-pulmonary tuberculosis in South Korea

SETTING

The Xpert(®) MTB/RIF assay has been endorsed by the World Health Organization for the detection of pulmonary and extra-pulmonary tuberculosis (EPTB).

OBJECTIVE

To determine the accuracy of the Xpert assay in diagnosing EPTB in South Korea, a country with an intermediate TB burden.

DESIGN

We retrospectively reviewed the medical records of 1429 patients in whom the Xpert assay using EPTB specimens was requested between 1 January 2011 and 31 October 2013 in a tertiary referral hospital in South Korea. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for the diagnosis of EPTB and detection of rifampicin (RMP) resistance were calculated.

RESULTS

Using culture as gold standard, the sensitivity, specificity, PPV and NPV of the assay were respectively 67.7%, 98.1%, 60% and 98.6%. Using a composite reference standard, the sensitivity, specificity, PPV and NPV were respectively 49.3%, 100%, 100% and 95.1%. The sensitivity, specificity, PPV and NPV for the detection of RMP resistance among specimens with positive results for Mycobacterium tuberculosis were respectively 80%, 100%, 100% and 97.7%.

CONCLUSION

The Xpert assay showed acceptable sensitivity in certain groups and excellent specificity in diagnosing EPTB and detecting RMP resistance in an intermediate TB burden country.

Very early osteoarthritis changes sensitively fluid flow properties of articular cartilage

In this study, fibril-reinforced poroelastic (FRPE) modeling was used for rabbit knee after anterior cruciate ligament transection (ACLT) to assess how the mechanical properties of collagen, proteoglycans, and fluid in articular cartilage change in early osteoarthritis, and how site-specific these changes are. Unilateral ACLT was performed in eight skeletally mature, female New Zealand white rabbits. A separate control (CTRL) group consisted of knee joints of five non-operated rabbits. Animals were sacrificed at four weeks after ACLT and cartilage-on-bone samples from femoral groove, medial and lateral femoral condyles, and tibial plateaus were harvested. A stress-relaxation protocol in indentation geometry was applied and the FRPE model was fitted to the experimental force-time curve by minimizing the mean absolute error between experiment and simulation. The optimized parameters were: fibril network modulus (Ef), representing the collagen network; non-fibrillar matrix modulus (Enf), representing the PG matrix; and permeability (k), representing fluid flow. Permeability was increased significantly in the ACLT group compared to the CTRL group knees at all sites except for the medial tibial plateau. ACLT also caused a decrease in the Ef at all sites except for the medial and lateral tibial plateaus. The Enf of the ACLT group knees was altered only for the lateral femoral condyle. The results of this study suggest that early osteoarthritis primarily affects cartilage permeability and impairs the collagen network stiffness in a site-specific manner. These findings from early osteoarthritis indicate that fluid flow velocity in articular cartilage may change prior to quantifiable structural alterations in the tissue.

Clinical results of treatment of garden type 1 and 2 femoral neck fractures in patients over 70-year old

INTRODUCTION

We retrospectively analyzed the clinical results of treatment of impacted or undisplaced femoral neck fractures (Garden types 1 and 2) by osteosynthesis in elderly patients >70-year old.

MATERIALS AND METHODS

We retrospectively reviewed the radiological results of 52 patients who were followed up for at least 6 months from April 2002 to December 2008. The average age of the patients was 77.6 years (range 70-97 years), and 38 patients were females. The mean follow-up period was 11.7 months (range 6-19 months). Thirteen cases were Garden type 1 fractures, and 39 were Garden type 2 fractures. We assessed the relationships between the occurrence of complications and age, sex, Garden stage, bone mineral density (BMD), history of contralateral hip fracture, and any additional hip injury.

RESULTS

Major complications occurred in 18 cases (34.6 %), including nonunion (8 cases), osteonecrosis (6 cases), stress fracture of the subtrochanter (2 cases), excessive pull-out of a screw (1 case), and deep infection (1 case). The development of complications was associated with Garden stage 2, BMD, and additional hip injury. However, other factors were not associated with complications. Reoperations were performed in 16 cases (30.1 %), and 2 of the patients died during follow-up.

CONCLUSION

A relatively high rate of complications or reoperations developed after treatment of Garden 2 femoral neck fractures in senile patients >70 years of age with osteoporosis. Although internal fixation has been recommended in the literature for undisplaced femoral neck fractures, primary arthroplasty may be a better option for treatment of Garden type 2 fractures in elderly patients.

Randomised controlled clinical trial for autologous fibroblast-hyaluronic acid complex in treating diabetic foot ulcers

OBJECTIVE

Diabetic foot ulcers (DFUs) often pose a treatment problem. Bioengineered skin substitutes have been reported to result in accelerated diabetic wound healing. The purpose of this clinical trial was to evaluate the efficacy and safety of the autologous fibroblast-hyaluronic acid complex for treating DFUs.

METHOD

A stratified, randomised, controlled, multicentre study was carried out. Patients with DFUs were allocated to either a treatment group with grafting of an autologous fibroblast-hyaluronic acid complex or a control group with non-adherent foam dressing. Except for application of the fibroblast complex, treatment of the study ulcers was identical for patients in both groups. The maximum follow-up period for each patient was 12 weeks.

RESULTS

Complete ulcer healing was achieved in 84% (26/31 patients) of the treatment group and 34% (11/32 patients) of the control group (p<0.05). The times required for complete healing were 36.4 ± 17.6 and 48.4 ± 13.1 days in the treatment and control groups, respectively (p<0.05). No adverse events related to treatment occurred.

CONCLUSION

These results indicate that autologous fibroblast-hyaluronic acid complex may offer a safe and effective treatment for DFUs.

Site-dependent changes in structure and function of lapine articular cartilage 4 weeks after anterior cruciate ligament transection

OBJECTIVE

The aim of this study was to investigate the site-dependent changes in the structure and function of articular cartilage in the lapine knee joint at a very early stage of osteoarthritis (OA), created experimentally by anterior cruciate ligament transection (ACLT).

METHODS

Unilateral ACLT was performed in eight mature New Zealand white rabbits. ACL transected and contralateral (C-L) joints were prepared for analysis at 4 weeks after ACLT. Three rabbits with intact joints were used as a control group (CNTRL). Femoral groove, medial and lateral femoral condyles, and tibial plateaus were harvested and used in the analysis. Biomechanical tests, microscopy and spectroscopy were used to determine the biomechanical properties, composition and structure of the samples. A linear mixed model was chosen for statistical comparisons between the groups.

RESULTS

As a result of ACLT, the equilibrium and dynamic moduli were decreased primarily in the femoral condyle cartilage. Up to three times lower moduli (P < 0.05) were observed in the ACLT group compared to the control group. Significant (P < 0.05) proteoglycan (PG) loss in the ACLT joint cartilage was observed up to a depth of 20-30% from the cartilage surface in femoral condyles, while significant PG loss was confined to more superficial regions in tibial plateaus and femoral groove. The collagen orientation angle was increased (P < 0.05) up to a cartilage depth of 60% by ACLT in the lateral femoral condyle, while smaller effects, but still significant, were observed at other locations. The collagen content was increased (P < 0.05) in the middle and deep zones of the ACLT group compared to the control group samples, especially in the lateral femoral condyle.

CONCLUSION

Femoral condyle cartilage experienced the greatest structural and mechanical alterations in very early OA, as produced by ACLT. Degenerative alterations were observed especially in the superficial collagen fiber organization and PG content, while the collagen content was increased in the deep tissue of femoral condyle cartilage. The current findings provide novel information of the early stages of OA in different locations of the knee joint.

Antiplatelet or anticoagulant therapy might not increase the risk of haemoptysis in patients with bronchiectasis

The aim of this study was to assess whether the use of antiplatelets and anticoagulants increased haemoptysis in patients with bronchiectasis. Cases (n = 242) with a history of haemoptysis were compared with controls (n = 242) without a history of haemoptysis. Of the 242 case patients, 16.5% took antiplatelets compared with 19.8% of controls (P = 0.346). The proportion of warfarin users did not differ between cases and controls (3.3% vs. 2.5%, P = 0.588). The use of these agents might not be associated with increased risk of haemoptysis in patients with bronchiectasis.

Genistein excitation of gonadotrophin-releasing hormone neurones in juvenile female mice

We investigated the effects of the phytoestrogen genistein on gonadotrophin-releasing hormone (GnRH) neurones using single-cell electrophysiology on GnRH-green fluorescent protein (GFP) transgenic juvenile female mice. Perforated patch-clamp recordings from GnRH-GFP neurones showed that approximately 83% of GnRH neurones responded to 30 μm genistein with a markedly prolonged membrane depolarisation. This effect not only persisted in the presence of tetrodotoxin, but also in the presence of amino acid receptor antagonists, indicating the direct site of action on postsynaptic GnRH neurones. Using a voltage clamp technique, we found that 30 μm genistein increased the frequency of synaptic current of GnRH neurones clamped at -60 mV in the presence of glutamate receptor blocker but not GABAA receptor blocker. Pre-incubation of GnRH neurones with 30 μm genistein enhanced kisspeptin-induced membrane depolarisation and firing. GnRH neurones of juvenile mice injected with genistein in vivo showed an enhanced kisspeptin response compared to vehicle-injected controls. The transient receptor potential channel (TRPC) blocker 2-aminoethoxydiphenyl borate (75 μm) blocked the genistein-mediated response on GnRH neurones. These results demonstrate that genistein acts on GnRH neurones in juvenile female mice to induce excitation via GABA neurotransmission and TRPCs to enhance kisspeptin-induced activation.

Diagnostic accuracy of Xpert® MTB/RIF on bronchoscopy specimens in patients with suspected pulmonary tuberculosis

OBJECTIVE

To determine the diagnostic accuracy of the Xpert® MTB/RIF assay using samples obtained through bronchoscopy in patients with suspected pulmonary tuberculosis (PTB).

DESIGN

We retrospectively reviewed the records of patients with suspected PTB for whom the Xpert MTB/RIF assay was performed on bronchoscopy specimens. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for the diagnosis of active PTB were calculated for acid-fast bacilli (AFB) smear microscopy and the Xpert assay using culture of Mycobacterium tuberculosis from sputum or bronchoscopy specimens as a reference standard.

RESULTS

A total of 132 patients were included in the final analysis. Of these, 38 had culture-confirmed PTB. The sensitivity of the Xpert assay using bronchial washing or bronchoalveolar lavage (BAL) fluid for the diagnosis of PTB was 81.6%, and specificity was 100%. The PPV and NPV were 100% and 92.1%, respectively. The sensitivity and specificity of AFB smear microscopy were respectively 13.2% and 98.8%.

CONCLUSION

The Xpert assay on bronchoscopy specimens provided an accurate diagnosis of PTB in patients who had a negative AFB smear or who could not produce sputum.

Cell deformation behavior in mechanically loaded rabbit articular cartilage 4 weeks after anterior cruciate ligament transection

OBJECTIVE

Chondrocyte stresses and strains in articular cartilage are known to modulate tissue mechanobiology. Cell deformation behavior in cartilage under mechanical loading is not known at the earliest stages of osteoarthritis. Thus, the aim of this study was to investigate the effect of mechanical loading on volume and morphology of chondrocytes in the superficial tissue of osteoarthritic cartilage obtained from anterior cruciate ligament transected (ACLT) rabbit knee joints, 4 weeks after intervention.

METHODS

A unique custom-made microscopy indentation system with dual-photon microscope was used to apply controlled 2 MPa force-relaxation loading on patellar cartilage surfaces. Volume and morphology of chondrocytes were analyzed before and after loading. Also global and local tissue strains were calculated. Collagen content, collagen orientation and proteoglycan content were quantified with Fourier transform infrared microspectroscopy, polarized light microscopy and digital densitometry, respectively.

RESULTS

Following the mechanical loading, the volume of chondrocytes in the superficial tissue increased significantly in ACLT cartilage by 24% (95% confidence interval (CI) 17.2-31.5, P < 0.001), while it reduced significantly in contralateral group tissue by -5.3% (95% CI -8.1 to -2.5, P = 0.003). Collagen content in ACLT and contralateral cartilage were similar. PG content was reduced and collagen orientation angle was increased in the superficial tissue of ACLT cartilage compared to the contralateral cartilage.

CONCLUSIONS

We found the novel result that chondrocyte deformation behavior in the superficial tissue of rabbit articular cartilage is altered already at 4 weeks after ACLT, likely because of changes in collagen fibril orientation and a reduction in PG content.

Recurrence after successful treatment among patients with multidrug-resistant tuberculosis

A retrospective review was conducted of patients with multidrug-resistant tuberculosis (MDR-TB) to elucidate the rate of recurrence after successful treatment. Of 123 MDR-TB patients, 90 were declared as 'cured' or 'treatment completed' after individualised treatment; four (4.4%) experienced recurrence. All patients with recur- rent MDR-TB were documented as 'treatment completed' after treatment. Recurrence of MDR-TB is possible after successful treatment, particularly among those documented as 'treatment completed'.

10-Gb/s transmission over 20-km single fiber link using 1-GHz RSOA by discrete multitone with multiple access

We demonstrate a novel 10.5-Gbit/s transmission scheme over 20-km single fiber link by using a remotely fed 1-GHz reflective semiconductor optical amplifier (RSOA). Discrete multitone (DMT) modulation with adaptive bit-/power-loading is applied to overcome the bandwidth limitation of the RSOA. Transmission performance of the proposed scheme is analyzed in terms of various system parameters, such as the nonlinearity of the RSOA, optical signal-to-noise ratio of the optical seed carrier, the overhead size impact on dispersion, the number of DMT subcarriers, and the reflection noise from the single fiber link. We also report flexible-bandwidth-allocated multiple access operation based on the proposed scheme. The throughput for all cases is approximately 10 Gbit/s with BER < 10(-3).

The impact of combined pulmonary fibrosis and emphysema on mortality

SETTING

The impact on patient mortality of combined pulmonary fibrosis and emphysema (CPFE) compared with emphysema alone has never been investigated.

OBJECTIVE

To elucidate whether CPFE has an impact on overall mortality over that of emphysema alone.

DESIGN

We screened patients who underwent chest computed tomography (CT) scans during the period from 1 January 2001 to 31 December 2005 in a tertiary referral hospital. Patients who had both emphysema and pulmonary fibrosis, thus meeting the inclusion criteria, were defined as CPFE. Controls with emphysema alone who were matched for age, sex and the date of CT scan were randomly selected. Cox proportional regression analysis was performed to verify whether CPFE is associated with increased overall mortality.

RESULTS

We found 135 CPFE cases. In the multivariable Cox regression stratified by the presence of comorbid malignancy, CPFE had five times higher mortality risk (adjusted HR 5.10, 95%CI 1.75-14.9) in non-malignant cases, and showed a statistically insignificant trend for higher mortality risk (adjusted HR 1.70, 95%CI 0.94-2.51) in the malignant cases after adjusting for forced vital capacity, height and hypertension.

CONCLUSION

CPFE is not rare and CPFE patients had a higher overall mortality risk than emphysema-only patients.

Impact of antibiotic prophylaxis on postbronchoscopy fever: a randomised controlled study

BACKGROUND

Postbronchoscopy fever can develop in 5-16% of adult patients. The microbiological contribution to postbronchoscopy fever is unclear.

OBJECTIVE

To elucidate the effect of prophylactic antibiotics on the development of postbronchoscopy fever and pneumonia.

DESIGN

Study patients were randomised to receive no treatment or oral amoxicillin/clavulanate 30 min before flexible bronchoscopy. The primary outcome variable was the frequency of postbronchoscopy fever and pneumonia. White blood cell counts, C-reactive protein and the serum pyrogenic cytokines interleukin (IL) 1β, IL-6 and tumour necrosis factor-alpha were measured before and after bronchoscopy.

RESULTS

Of 143 subjects enrolled in the study, the final analysis was performed among 67 subjects in the prophylaxis group and 64 in the control group. The frequency of postbronchoscopy fever did not differ between the groups (25.4% for the prophylaxis group vs. 26.6% for controls, P > 0.05). Pneumonia developed in 1.5% of the prophylaxis group and 4.7% of the controls. There was no bacteraemia in either group. Serum pyrogenic cytokines did not differ between the groups.

CONCLUSIONS

Prophylactic antibiotics before bronchoscopy did not reduce the frequency of postbronchoscopy fever and did not affect serum levels of pyrogenic cytokines. These findings suggest that microbiological factors may not be responsible for the development of postbronchoscopy fever.

Optimization of selective emitter fabrication method for solar cells using a laser grooving

In this paper, screen-printing laser grooved buried contact (LGBC) method was applied, which is compatible with the existing screen-printed solar cell equipment and facilities. Experiments were performed in order to optimize short circuit current (I(sc)), open circuit voltage (V(oc)) and fill factor of high efficiency solar cells. To enhance I(sc), V(oc) and efficiency, heavy doping was performed at low sheet resistance in the laser grooved region of the cell. In contrast, light doping was carried out at a high sheet resistance in the non-laser grooved region. To increase fill factor, porous silicon found on the wafer after dipping in an HF solution to remove SiN(x), was cleared. The fabricated screen-printing LGBC solar cell using a 125 mm x 125 mm single crystalline silicon wafer exhibited an efficiency of 17.2%. The results show that screen-printing LGBC method can be applied for high efficiency solar cells.

Unexplained Massive Pneumoperitoneum following Cardiopulmonary Resuscitation

Pneumoperitoneum following cardiopulmonary resuscitation (CPR) had been described as a rare complication. Pneumoperitoneum after CPR could be due to gastric perforation or intrathoracic air tracking into the abdominal cavity via the diaphragm as a result of bag-valve-mask ventilation, external chest compression or improper intubation. In most reported cases, the specific injuries could be identified. We reported an unusual case of pneumoperitoneum following CPR in which the specific cause was not definitely established. Emergency physicians should be aware of the mechanism and clinical signs suggesting of pneumoperitoneum during or after CPR.

Risk factors for multidrug-resistant bacterial infection among patients with tuberculosis

Given that anti-tuberculosis medication itself has antibacterial activity and that broad-spectrum antibiotics are frequently used, the emergence of multidrug-resistant (MDR) bacteria among patients being treated for tuberculosis (TB) is likely. We used a case-control design to study the clinical predictors of MDR bacterial infection among TB patients. Both cases and controls were selected from among patients who were diagnosed and treated as having TB between 1 January 1996 and 31 August 2006. TB patients with MDR bacterial infection were included as cases and those with non-MDR bacterial infection were included as controls. Multiple logistic regression analysis was performed to elucidate the risk factors for MDR bacterial infection. During the study period 3667 patients were diagnosed with, and treated for, TB. A total of 123 experienced episodes of bacterial infection, of whom 59 (48.0%) were infected by an MDR strain at least once. The presence of chronic renal failure [adjusted odds ratio (OR): 4.96; 95% confidence interval (CI): 1.37-18.01] and the use of antimicrobials other than typical anti-TB drugs within three months (adjusted OR: 4.37; 95% CI: 1.74-10.95) were independent risk factors for MDR bacterial infection. Bacterial infection in TB patients is commonly multidrug resistant. Clinicians should be aware of the possibility of MDR bacterial infection among TB patients with chronic renal failure or recent use of other antimicrobials.

Rapid increase of non-tuberculous mycobacterial lung diseases at a tertiary referral hospital in South Korea

The incidence of non-tuberculous mycobacteria (NTM) disease is thought to correlate negatively with the tuberculosis (TB) burden. To determine the recent trend in the number of patients with NTM lung disease at a tertiary referral hospital in South Korea, where the incidence of TB has been stationary, a retrospective analysis was performed. From 2002 to 2008, the number of patients with NTM lung diseases increased from 82 to 133, while the number of TB patients decreased from 436 to 276. NTM lung diseases might be increasing in South Korea despite the stationary incidence of TB.

The impact of insulin sensitisers on lung function in patients with chronic obstructive pulmonary disease and diabetes

SETTING

It has been reported that diabetes mellitus (DM) is associated with poor pulmonary function, which could be explained by insulin resistance.

OBJECTIVE

To evaluate whether insulin sensitisers (ISs) have beneficial effects on lung function in patients with chronic obstructive pulmonary disease (COPD) and DM.

DESIGN

This retrospective study included patients with both COPD and DM who attended Seoul National University Hospital for treatment between 1 January 2000 and 31 August 2007. They were treated with inhalers for COPD and oral hypoglycaemia agents, including ISs or insulin, for DM. The primary outcome was a change in lung function in spirometric examinations.

RESULTS

Among 61 patients enrolled, 32 were in the no IS group, while 29 were in the IS group. On multivariable regression analysis, the IS group showed a significantly greater change in forced vital capacity (FVC) than the no IS group (adjusted beta-coefficient 131.9, 95%CI 8.5-255.4, P = 0.04).

CONCLUSIONS

Treatment with an IS was independently associated with improvements in FVC in patients with both COPD and DM, compared with treatment without IS.

Gonadotrophin-releasing hormone (GnRH) exerts stimulatory effects on GnRH neurons in intact adult male and female mice

There is substantial evidence for a role of the neuropeptide gonadotrophin-releasing hormone (GnRH) in the regulation of GnRH neurone secretion but how this is achieved is not understood. We examined here the effects of GnRH on the electrical excitability and intracellular calcium concentration ([Ca2+](i)) of GnRH neurones in intact adult male and female mice. Perforated-patch electrophysiological recordings from GnRH-green fluorescent protein-tagged GnRH neurones revealed that 3 nm-3 mum GnRH evoked gradual approximately 3 mV depolarisations in membrane potential from up to 50% of GnRH neurones in male and female mice. The depolarising effect of GnRH was observed on approximately 50% of GnRH neurones throughout the oestrous cycle. However, at pro-oestrus alone, GnRH was also found to transiently hyperpolarise approximately 30% of GnRH neurones. Both hyperpolarising and depolarising responses were maintained in the presence of tetrodotoxin. Calcium imaging studies undertaken in transgenic GnRH-pericam mice showed that GnRH suppressed [Ca2+](i) in approximately 50% of GnRH neurones in dioestrous and oestrous mice. At pro-oestrus, 25% of GnRH neurones exhibited a suppressive [Ca2+](i) response to GnRH, whereas 17% were stimulated. These results demonstrate that nm to mum concentrations of GnRH exert depolarising actions on approximately 50% of GnRH neurones in males and females throughout the oestrous cycle. This is associated with a reduction in [Ca2+](i). At pro-oestrus, however, a further population of GnRH neurones exhibit a hyperpolarising response to GnRH. Taken together, these studies indicate that GnRH acts predominantly as a neuromodulator at the level of the GnRH cell bodies to exert a predominant excitatory influence upon GnRH neurones in intact adult male and female mice.

The impact of nutritional deficit on mortality of in-patients with pulmonary tuberculosis

SETTING

A metropolitan governmental medical centre, Seoul, Republic of Korea.

OBJECTIVE

To elucidate the impact of the nutritional deficit assessed by the Nutritional Risk Score (NRS) on the outcomes of in-patients with pulmonary tuberculosis (PTB).

DESIGN

All hospitalised patients with microbiologically confirmed PTB were enrolled. A four-point NRS included low body mass index (<18.5 kg/m(2)), hypoalbuminaemia (<30.0 g/l), hypocholesterolaemia (<2.33 mmol/l) and severe lymphocytopaenia (<7 x 10(5) cells/l). The primary outcome was overall in-hospital mortality. The degree of radiographical resolution after anti-tuberculosis treatment was also evaluated.

RESULTS

In a total of 156 patients, the male to female ratio was 1.6:1. The overall mortality was 13.5% and tuberculosis-specific fatality was 3.9%. Predisposing factors and high NRS (> or = 3 points) were independent risk factors for in-hospital death after adjusting for the severity of PTB. High NRS (OR = 16.8, P < 0.001) and predisposing factors (OR = 5.4, P = 0.032) were independent risk factors for 30-day survival. The NRS was not associated with radiographic improvement.

CONCLUSION

Regardless of disease severity, the high NRS was a significant negative predictor among in-patients with PTB; this finding should therefore be considered in the management of PTB despite the current era of effective anti-tuberculosis chemotherapy.

Isolation and characterization of bacteriocin-producing bacteria from the gastrointestinal tract of broiler chickens for probiotic use

AIMS

To isolate and characterize the bacteriocin-producing bacteria (BPB) from the gastrointestinal tract of broiler chickens for probiotic use.

METHODS AND RESULTS

In total, 291 bacterial strains were isolated from broilers and screened for bacteriocin-producing ability. The bacteriocins produced by Enterococcus faecium SH 528, Ent. faecium SH 632 and Pediococcus pentosaceus SH 740 displayed inhibitory activity against pathogens including Clostridium perfringens and Listeria monocytogenes. Activity of the bacteriocins remained unchanged after 30 min of heat treatment at 60 degrees C or exposure to organic solvents, but diminished after treatment with proteolytic enzymes. PCR was used to detect the structural genes enterocin A and B in SH 528, enterocin L50 and P in SH 632, and pediocin PA-1 in SH 740. Most of them were resistant to 0.5% bile salts and remained viable after 2 h at pH 3.0. Ent. faecium SH 528 exhibited the highest amylase activity among the strains tested.

CONCLUSIONS

We selected Ent. faecium SH 528 and SH 632 and Ped. pentosaceus SH 740 by probiotic selection criteria including inhibition activity against pathogens.

SIGNIFICANCE AND IMPACT OF THE STUDY

The isolated BPB could potentially be used in the poultry industry as probiotics to control pathogens.

Studies on red cell carbonic anhydrase types in Korean cattle

Red cell carbonic anhydrase types in Korean cattle were investigated by means of starch gel electrophoresis. A carbonic anhydrase zone (X) located ahead zone F was found in 12 out of 502 Korean cattle. The distribution of CA phenotypes in 490 Korean cattle was CA FS type 92 and CA SS type 398. The CA FF type has not yet been recognized in Korean cattle. The gene frequencies were CAF = 0.094 and CAS = 0.906. No statistically significant differences were observed between gene frequencies in cattle from six different Korea provinces.

Studies on hemoglobin variants in Korean cattle

814 hemoglobin samples from Korean cattle were investigated by starch gel electrophoresis for the detection of hemoglobin variants. A new variant of cattle hemoglobin, called Hb, H, was recognized. It has a slower rate of migration than Hb A. Hemoglobin types from 814 Korean cattle were as follows: 652 of Hb AA type (80.1%), 133 of Hb AB (16.4%), 12 of Hb AC (1.5%), 9 of Hb BB (1.1%), 2 of Hb BC (0.2%), 4 of Hb AH (O.5%), 1 of Hb CH (0.1%), 1 of Hb HH (O.1%). These figures correspond to the frequencies: HbA = 0.893, HbB = 0.093, HbC = 0.009, HbH = 0.004.

Is the foot elevation the optimal position for wound healing of a diabetic foot?

In managing diabetic foot ulcers, foot elevation has generally been recommended to reduce oedema and prevent other sequential problems. However, foot elevation may decrease tissue oxygenation of the foot more than the dependent position since the dependent position is known to increase blood flow within the arterial system. In addition, diabetic foot ulcers, which have peripheral vascular insufficiency, generally have less oedema than other wounds. Therefore, we argue that foot elevation may not be helpful for healing of vascularly compromised diabetic foot ulcers since adequate tissue oxygenation is an essential factor in diabetic wound healing. The purpose of this study was to evaluate the influence of foot height on tissue oxygenation and to determine the optimal foot position to accelerate wound healing of diabetic foot ulcers. This study included 122 cases (73 males and 47 females; two males had bilateral disease) of diabetic foot ulcer patients aged 40-93 years. Trans-cutaneous partial oxygen tension (TcpO(2)) values of diabetic feet were measured before and after foot elevation (n=21). Elevation was achieved by placing a foot over four cushions. We also measured foot TcpO(2) values before and after lowering the feet (n=122). Feet were lowered to the patient's tibial height, approximately 30-35 cm, beside a bed handrail. Due to the large number of lowering measurements, we divided them into five sub-groups according to initial TcpO(2.) Tissue oxygenation values were compared. Foot-elevation-lowered TcpO(2) values before and after elevation were 32.5+/-22.2 and 23.8+/-23.1 mmHg (p<0.01), respectively. Foot-lowering-augmented TcpO(2) values before and after lowering were 44.6+/-23.8 and 58.0+/-25.9 mmHg (p<0.01), respectively. The lower the initial TcpO(2) level, the more the TcpO(2) level increased. The foot lowering, rather than elevation, significantly augments TcpO(2) and may stimulate healing of diabetic foot ulcers.

Decreased phosphorylation of STAT-1, STAT-4 and cytokine release in MDR-TB patients with primary resistance

SETTING

We recently showed that treatment failure rate was higher among multidrug-resistant tuberculosis (MDR-TB) patients without a previous history of tuberculosis (TB) treatment, or so-called 'primary resistance'.

OBJECTIVE

To investigate the phosphorylation levels of signal transducers and activators of transcription-1 (STAT-1) and STAT-4 and the subsequent cytokine release as a possible cause of a poor prognosis in MDR-TB patients with primary resistance.

DESIGN

Ten patients with successfully treated pulmonary TB without resistance, 12 MDR-TB patients with acquired resistance and 10 MDR-TB patients with primary resistance were enrolled. After 24 h stimulation of peripheral blood mononuclear cells (PBMC) with interferon-gamma (IFN-gamma), interleukin-12 (IL-12), purified protein derivative (PPD), or lysate of Mycobacterium tuberculosis, flow cytometric analysis of intracellular pSTAT-1 and pSTAT-4 were performed and secretion of IFN-gamma, IL-12p40 and tumour necrosis factor-alpha (TNF-alpha) was measured in culture supernatant.

RESULTS

The mean fluorescent intensities of pSTAT-1 and pSTAT-4 in PBMC of MDR-TB patients with primary resistance decreased on stimulation of IFN-gamma, PPD or lysate of M. tuberculosis when compared with patients with acquired resistance. In addition, secretion of IFN-gamma, IL-12p40 and TNF-alpha in these patients decreased on various stimuli.

CONCLUSION

Decreased phosphorylation of STAT-1, STAT-4, and of subsequent cytokine release, might be associated with a poor prognosis in MDR-TB patients with primary resistance.

Isolation and partial characterization of a bacteriocin produced by Pediococcus pentosaceus K23-2 isolated from Kimchi

AIMS

Screening and partial characterization of a bacteriocin produced by Pediococcus pentosaceus K23-2 isolated from Kimchi, a traditional Korean fermented vegetable.

METHODS AND RESULTS

A total of 1000 lactic acid bacteria were isolated from various Kimchi samples and screened for the production of bacteriocin. Pediocin K23-2, a bacteriocin produced by the Pediococcus pentosaceus K23-2 strain, showed strong inhibitory activity against Listeria monocytogenes. The bacteriocin activity remained unchanged after 15 min of heat treatment at 121 degrees C or exposure to organic solvents; however, it diminished after treatment with proteolytic enzymes. The bacteriocin was maximally produced at 37 degrees C, when the pH of the culture broth was maintained at 5.0 during the fermentation, although the optimum pH for growth was 7.0. The molecular weight of the bacteriocin was about 5 kDa according to a tricine SDS-PAGE analysis.

CONCLUSIONS

Pediococcus pentosaceus K23-2 isolated from Kimchi produces a bacteriocin, which shares similar characteristics to the Class IIa bacteriocins. The bacteriocin is heat stable and shows wide antimicrobial activity against Gram-positive bacteria, especially L. monocytogenes.

SIGNIFICANCE AND IMPACT OF THE STUDY

Pediocin K23-2 and pediocin K23-2-producing P. pentosaceus K23-2 could potentially be used in the food and feed industries as natural biopreservatives, and for probiotic application to humans or livestock.

Nutritional deficit as a negative prognostic factor in patients with miliary tuberculosis

The effects of malnutrition on outcomes in miliary tuberculosis (MTB) are not well described. The aim of the present study was to find predictors for the development of acute respiratory failure (ARF) and survival in MTB patients, focusing on parameters reflecting nutritional condition. Out of the patients from three hospitals who had microbiologically or histopathologically confirmed tuberculosis, 56 patients presenting with typical disseminated pulmonary nodules on radiographs were retrospectively enrolled. A four-point nutritional risk score (NRS) was defined according to the presence of four nutritional factors: low body mass index (BMI; <18.5 kg x m(-2)), hypoalbuminaemia (<30.0 g x L(-1)), hypocholesterolaemia (<2.33 mmol x L(-1)) and severe lymphocytopenia (<7 x 10(5) cells x L(-1)). The male to female ratio was 1:3. ARF developed in 25% of patients (14 out of 56), with a 50% fatality rate. A high NRS (> or =3 points) was an independent risk factor for the development of ARF and fatality. In 90-day survival analysis, ARF, severe lymphocytopenia, hypocholesterolaemia, low BMI and higher NRS were risk factors for poor outcome. In multivariate analysis, only high NRS was an independent risk factor for 90-day survival rate in patients with MTB. A high nutritional risk score was a good predictor of poor outcome in miliary tuberculosis patients. Additional approaches to recover the nutritional deficits may become a focus in future management of miliary tuberculosis.

EPR studies of in vivo radical production by 3,3',5,5'-tetrabromobisphenol A (TBBPA) in the Sprague-Dawley rat

Brominated flame retardants (BFRs) are present in many consumer products ranging from fabrics to plastics and electronics. Wide use of flame retardants can pose an environmental hazard and it is of interest to determine the mechanism of their toxicity. Of all the BFRs, 3,3',5,5'-tetrabromobisphenol A (TBBPA) is produced in the largest volume. Previous studies by Szymanska et al. (2000) have shown that TBBPA is hepatotoxic in rats. We report here that when TBBPA (100 or 600 mg/kg) dissolved in DMSO and alpha-(4-pyridyl-1-oxide)-N-t-butylnitrone (POBN) was administered ip to male Sprague-Dawley rats the POBN/CH(3) spin adduct was detected by electron paramagnetic resonance (EPR) in the bile. When (13)C-DMSO was employed the POBN/C(13)H(3) adduct was observed. Also present in the bile was the 2,6-dibromobenzosemiquinone radical derived from 2,6-dibromohydroquinone, a known metabolite of TBBPA. Reaction of the 2,6-dibromobenzosemiquinone radical with oxygen would generate superoxide from which hydrogen peroxide can form by dismutation. The hydroxyl radical generated via the Fenton reaction from hydrogen peroxide reacts in vivo with DMSO to give the methyl radical which is trapped by POBN. These observations suggest that the hepatotoxicity of TBBPA in rats may be due to the in vivo generation of the hydroxyl radical as a result of redox reactions involving the TBBPA metabolite 2,6-dibromohydroquinone and its corresponding semiquinone radical.

Oxidation of flame retardant tetrabromobisphenol A by singlet oxygen

Wide use of flame retardants can pose an environmental hazard, and it is of interest to investigate how they may degrade. We report here that 3,3',5,5'-tetrabromobisphenol A (TBBPA) is subject to photosensitized oxidation involving singlet molecular oxygen ((1)O2). By using visible light and rose bengal or methylene blue as 102 photosensitizers, we have found that TBBPA is a 102 quencher. The quenching rate constant, k(q), depends on TBBPA ionization (pK = 7.4). In acetonitrile, where TBBPA is undissociated, the kq value is 6.1 x 10(5) M(-1) s(-1) for a TBBPA monomer and decreases to 2.9 x 10(4) M(-1) s(-1) for TBBPA dimers and/or aggregates. TBBPA dissociates in aqueous solutions, and its kq value is 1.44 x 10(9) M(-1) s(-1) in alkaline solution, decreasing to 3.9 x 10(8) M(-1) s(-1) at pH 7.2. The strong 102 quenching by TBBPA anion initiates an efficient oxidation of TBBPA, which results in oxygen consumption in aqueous micellar (e.g., Triton X-100) solutions containing photosensitizer. This oxygen consumption is mediated by transient radical species, which we detected by using EPR spectroscopy. We observed two major radicals and one minor radical generated from TBBPA by reaction with 102 at pH 10. One was identified as the 2,6-dibromo-p-benzosemiquinone radical (a2H = 2.36 G, g = 2.0056). A second radical (aH = 2.10 G, g = 2.0055) could not be identified butwas probably a 2,6-dibromo-p-benzosemiquinone radical containing an EPR-silent substituent at the 3-position. Spin trapping with 5,5-dimethyl-1-pyrroline N-oxide (DPMO) showed that other minor radicals (hydroxyl, carbon-centered) are also generated during the reaction of TBBPA with (1)O2. The photosensitized production of radicals and oxygen consumption were completely inhibited by the azide anion, an efficient physical (1)O2 quencher. Because TBBPA is a stable compound that at neutral pH does not absorb much of the atmosphere-filtered solar radiation, its photosensitized oxidation by (1)O2 may be the key reaction initiating or mediating TBBPA degradation in the natural environment.

Predictors of persistent airway stenosis in patients with endobronchial tuberculosis

SETTING

The university and municipal hospitals in Seoul, Korea.

OBJECTIVE

To evaluate the predictors of persistent airway stenosis following anti-tuberculosis chemotherapy in patients with endobronchial tuberculosis (TB).

DESIGN

Diagnosis of TB was confirmed by microbiology or histopathology. Bronchoscopic examinations revealed that patients had endobronchial lesions compatible with endobronchial TB. Study subjects had at least one follow-up bronchoscopy to evaluate their treatment response. Treatment response was determined by changes in the degree or extent of airway stenosis between the first and last bronchoscopic examinations.

RESULTS

Sixty-seven subjects were recruited retrospectively from Seoul National University Hospital and Seoul National University Boramae Hospital. Persistent bronchostenosis occurred in 41.8% of the patients. In multivariate regression analysis, age >45 years (OR 3.65), pure or combined fibrostenotic subtype (OR 5.54) and duration from onset of chief complaint to the initiation of anti-tuberculosis chemotherapy >90 days (OR 5.98) were identified as independent predictors of persistent airway stenosis. Oral corticosteroids (prednisolone equivalent >or=30 mg/d) did not reduce the frequency of persistent airway stenosis.

CONCLUSION

Early diagnosis and early administration of anti-tuberculosis chemotherapy before involvement of the deeper airways is important to prevent the development of unwanted sequelae of bronchostenosis.

Anatomy of the alar lobule in the Asian nose

OBJECTIVE

To provide details of the unique anatomical features on the alar lobule region in the Asian nose.

METHODS

We hypothesized that the shape of the alar lobule is dependent on its anatomy. The alar lobules were classified into flared type and straight type depending on their gross prominence and roundness. A total of 20 fresh cadaver noses (10 of each type) were dissected. Anatomical differences between the flared and straight types were investigated by gross and histologic studies.

RESULTS

The alar lobule consisted of three layers; external skin, muscle, and vestibular skin. The dilator naris anterior and dilator naris posterior muscles were well developed in the flared type alar lobules, whereas they were poorly developed in the straight type. The insertion of the dilator naris posterior muscle in the flared type was found to extend more anteriorly to the middle of alar lobule as well as to the alar base, whereas in the straight type the insertion was limited to the alar base only. External skin at the lateral end of the flared type was thicker than of the straight type. No significant differences were seen in other structures of the alar lobule region.

CONCLUSIONS

The gross appearance of the alar lobule is mainly affected by the volume of the dilator naris anterior muscle, the insertion of the dilator naris posterior muscle, and the thickness of the external skin at the lateral end of the alar circumference.

Aetiologies and predictors of pulmonary cavities in South Korea

OBJECTIVE

To identify the aetiologies of pulmonary cavities and the clinical predictors of cavities of mycobacterial origin.

SETTING

A tertiary referral hospital in South Korea, where the prevalence of tuberculosis (TB) is intermediate.

DESIGN

A retrospective review of clinical records and radiographic examinations of patients presenting pulmonary cavities on simple chest radiograph between January and December 2005.

RESULTS

Of 131 patients enrolled with pulmonary cavities, 66 (50.4%) had cavities of mycobacterial origin. Age <50 years (P = 0.04) and largest cavity located in the upper lobes (P = 0.04) increased the likelihood that the cavities were of mycobacterial origin. Conversely, history of malignancy (P = 0.02), lesions confined to one lobe (P = 0.02) and multiple enlarged mediastinal lymph nodes (P = 0.03) suggested a non-mycobacterial cause.

CONCLUSION

Mycobacterial infection accounted for half of the cavitary lesions identified in this study. In older patients with a history of malignancy, non-nodular infiltration, lesions confined to one lobe and with multiple lymphadenopathy, diseases not caused by mycobacteria should be considered.

Determinants of diagnostic bronchial washing in peripheral lung cancers

OBJECTIVE

To establish clinical determinants affecting the diagnostic yield of bronchial washing.

SETTING

We performed bronchial washing in 241 consecutive patients with bronchoscopically invisible lung tumours. Of these, 150 patients known to have lung cancer were enrolled for the final analysis.

DESIGN

A multi-centre study.

RESULTS

Bronchial washing provided a diagnosis of lung cancer in 30 of the 150 patients (20%). Tumour size > or = 3 cm (P = 0.005), the location of the tumour within 8 cm of the carina (P = 0.003), and exposed type bronchus sign of tumour (P < 0.001) were factors affecting diagnostic bronchial washing for bronchoscopically invisible lung cancers. However, multivariate logistic regression revealed that exposed type bronchus sign was the sole determinant (OR 19.22, 95% CI 4.23-87.46, P < 0.001).

CONCLUSION

Bronchial washing is a useful procedure for the diagnosis of bronchoscopically invisible lung cancers. As the tumour-bronchus relationship is the most important determinant of a diagnostic yield, the routine use of bronchial washing should be considered for tumours with exposed type bronchus sign.

Prognostic factors for surgical resection in patients with multidrug-resistant tuberculosis

Although surgical lung resection could improve prognosis in some patients with multidrug-resistant tuberculosis (MDR-TB), there are no reports on the optimal candidates for this surgery. The aim of the present study was to elucidate the prognostic factors for surgery in patients with MDR-TB. Patients who underwent lung resection for the treatment of MDR-TB between March 1993 and December 2004 were included in the present study. Treatment failure was defined as greater than or equal to two of the five cultures recorded in the final 12 months of treatment being positive, any one of the final three cultures being positive, or the patient having died during treatment. The variables that affected treatment outcomes were identified through univariate and multivariate logistic regression analysis. In total, 79 patients with MDR-TB were included in the present study. The treatment outcomes of 22 (27.8%) patients were classified as failure. A body mass index <18.5 kg x m(-2), primary resistance, resistance to ofloxacin and the presence of a cavitary lesion beyond the range of the surgical resection were associated with treatment failure. Low body mass index, primary resistance, resistance to ofloxacin and cavitary lesions beyond the range of resection are possible poor prognostic factors for surgical lung resection in multidrug-resistant tuberculosis patients.

Lack of association between COPD and transforming growth factor-beta1 (TGFB1) genetic polymorphisms in Koreans

OBJECTIVE

Many genetic variations have been suggested as genetic risk factors for the development of chronic obstructive pulmonary disease (COPD), including single nucleotide polymorphisms in the transforming growth factor-beta1 (TGFB1) gene. We attempted to elucidate the association between TGFB1 genetic polymorphisms and COPD among Koreans.

DESIGN

The genotypes of 102 male patients with COPD and 159 volunteers with similar distributions of age, sex and smoking intensity, as well as normal pulmonary function, were determined for three previously associated TGFB1 single nucleotide polymorphisms (SNPs), -10807G/A (rs2241712) and -509T/C (rs1800469), located in or near the promoter, and 29T/C (rs1982073), located in exon 1 of the TGFB1 gene.

RESULTS

No significant associations between COPD and the three TGFB1 SNPs could be identified. In addition, the haplotypes composed of three TGFB1 SNPs were not associated with the presence of COPD.

CONCLUSION

These results differ from previous reports involving Caucasians, and might reflect racial differences in the pathogenesis of COPD.

The association between microsatellite polymorphisms in intron II of the human Toll-like receptor 2 gene and tuberculosis among Koreans

The observation that Toll-like receptor (TLR)2-deficient mice are highly susceptible to mycobacteria suggests that mutations altering TLR2 expression may impair host response to Mycobacterium tuberculosis. We evaluated the association between guanine-thymine (GT) repeat polymorphism in intron II of the TLR2 gene and the presence of tuberculosis (TB) in Koreans. The numbers of GT repeats were determined by PCR and gene scans for 176 TB patients and 196 controls. The recombinant TLR2 promoter/exonI/exonII/intronII/luciferase constructs including three representative repeats: (GT)13, (GT)20, and (GT)24 were transfected into K562 cells, and luciferase activities were estimated and compared. The expression of TLR2 on CD14+ peripheral blood mononuclear cells (PBMC) from healthy volunteers were measured with flow cytometry. Genotypes with shorter GT repeats were more common among TB patients (49.4 vs 37.7%, P=0.02). This observation was confirmed among 82 other TB patients as a validation cohort. Shorter GT repeats were associated with weaker promoter activities and lower TLR2 expression on CD14+ PBMCs. In conclusion, the development of TB disease in Koreans was associated with shorter GT repeats in intron II of the TLR2 gene. This association is correlated with lower expression of TLR2 through weaker promoter activity for genes with shorter GT repeats.

The Mechanical Behaviour of Chondrocytes Predicted with a Micro-structural Model of Articular Cartilage

The integrity of articular cartilage depends on the proper functioning and mechanical stimulation of chondrocytes, the cells that synthesize extracellular matrix and maintain tissue health. The biosynthetic activity of chondrocytes is influenced by genetic factors, environmental influences, extracellular matrix composition, and mechanical factors. The mechanical environment of chondrocytes is believed to be an important determinant for joint health, and chondrocyte deformation in response to mechanical loading is speculated to be an important regulator of metabolic activity. In previous studies of chondrocyte deformation, articular cartilage was described as a biphasic material consisting of a homogeneous, isotropic, linearly elastic solid phase, and an inviscid fluid phase. However, articular cartilage is known to be anisotropic and inhomogeneous across its depth. Therefore, isotropic and homogeneous models cannot make appropriate predictions for tissue and cell stresses and strains. Here, we modelled articular cartilage as a transversely isotropic, inhomogeneous (TI) material in which the anisotropy and inhomogeneity arose naturally from the microstructure of the depth-dependent collagen fibril orientation and volumetric fraction, as well as the chondrocyte shape and volumetric fraction. The purpose of this study was to analyse the deformation behaviour of chondrocytes using the TI model of articular cartilage. In order to evaluate our model against experimental results, we simulated indentation and unconfined compression tests for nominal compressions of 15%. Chondrocyte deformations were analysed as a function of location within the tissue. The TI model predicted a non-uniform behaviour across tissue depth: in indentation testing, cell height decreased by 43% in the superficial zone and between 11 and 29% in the deep zone. In unconfined compression testing, cell height decreased by 32% in the superficial zone, 25% in the middle, and 18% in the deep zones. This predicted non-uniformity is in agreement with experimental studies. The novelty of this study is the use of a cartilage material model accounting for the intrinsic inhomogeneity and anisotropy of cartilage caused by its microstructure.

Simultaneous treatment of sewage sludge and food waste by the unified high-rate anaerobic digestion system

This study aimed to evaluate the performance of the unified high-rate anaerobic digestion (UHAD) system treating co-substrate of sewage sludge and food waste. A 24-hr operating sequence consisted of four steps including fill, react, settle, and draw. The effects of co-substrate and organic loading rate (OLR) on the performance were investigated to verify the system applicability. In each OLR, the UHAD system showed higher CH4 recovery (> 70%), CH4 yield (0.3 L CH4/g VSadded) and CH4 production rate (0.6 L CH4/L/d) than the control system. In the specific methanogenic activity (SMA) tests on thermophilic biomass of the UHAD system, the average SMA of acetate (102 mL CH4/gVSS/d) was much higher than those of butyrate (85 mL CH4/g SS/d) and propionate (42 mL CH4/gVSS/d). It was demonstrated that the UHAD system for co-digestion resulted in higher methane yield and methane production rate due to sequencing batch operation, thermophilic digestion, and co-digestion. The enhanced performance could be attributed to longer retention time of active biomass, faster hydrolysis, higher CH4 conversion rate, and balanced nutrient conditions of co-substrate in the UHAD system. Consequently, this optimized unification could be a viable option for the simultaneous treatment of two types of OFMSW with high stability.

Impact of fluoroquinolones on the diagnosis of pulmonary tuberculosis initially treated as bacterial pneumonia

OBJECTIVE

The excellent in vitro activity of fluoroquinolones against Mycobacterium tuberculosis has raised concerns about the delayed diagnosis of pulmonary tuberculosis (PTB) initially misdiagnosed as pneumonia. The aim of this study was to assess the effect of empiric fluoroquinolone therapy on delays in diagnosis in patients with PTB initially misdiagnosed as bacterial pneumonia.

DESIGN

Patients with PTB initially treated as having community-acquired pneumonia and treated with fluoroquinolones for more than 5 consecutive days, from January 2000 to December 2004, were enrolled. As a control group, TB patients initially treated with nonfluoroquinolone antibiotics were enrolled. We reviewed the clinical data and compared treatment responses between the two groups.

RESULTS

Nine patients in the fluoroquinolone group and 19 patients in the non-fluoroquinolone group were enrolled. In the fluoroquinolone group, eight patients (89%) improved clinically or radiographically, whereas only eight patients (42%) in the non-fluoroquinolone group improved (P = 0.04). The delay in initiation of anti-tuberculosis medication was longer in the fluoroquinolone group than in the non-fluoroquinolone group (43.1 - 40.0 vs. 18.7 +/- 16.9 days, P = 0.04).

CONCLUSION

Delay in the initiation of anti-tuberculosis treatment is possible in patients administered fluoroquinolone and initially misdiagnosed as having bacterial pneumonia.

Interstitial lung disease in patients with polymyositis, dermatomyositis and amyopathic dermatomyositis

OBJECTIVE

To assess the prevalence, characteristics and prognostic factors of interstitial lung disease (ILD) in Korean patients with polymyositis (PM), dermatomyositis (DM) and amyopathic dermatomyositis (ADM).

METHODS

We reviewed the medical records of 72 consecutive PM and DM patients, including six patients with ADM, who were seen at the Rheumatology Clinic of Seoul National University Hospital between 1984 and 2003.

RESULTS

Twenty-nine PM/DM patients (40.3%) developed ILD. Anti-Jo-1 antibody and arthralgia were associated with the presence of ILD (P = 0.022 and P = 0.041, respectively), whereas dysphagia was more frequently found in patients without ILD (P = 0.041). Lung biopsies revealed diffuse alveolar damage (DAD) (n = 2), usual interstitial pneumonia (UIP) with DAD (n = 2), UIP (n = 1), and non-specific interstitial pneumonia (n = 2). Of the 29 patients, 11 (37.9%) died. The mean survival time in ILD patients was significantly shorter than in those without ILD (13.8+/-1.8 vs 19.2+/-0.9 yr, P = 0.017). Poor survival in ILD patients was associated with a Hamman-Rich-like presentation (P = 0.0000), ADM features (P = 0.0001) and an initial forced vital capacity (FVC) < or =60% (P = 0.024).

CONCLUSIONS

ILD was observed in 40.3% of Korean PM/DM patients and was associated with poor survival. A Hamman-Rich-like presentation, ADM features and an initial FVC < or =60% were associated with poor survival in ILD.

Oral insertion of a flexible bronchoscope is associated with less discomfort than nasal insertion for Korean patients

OBJECTIVE

The route of bronchoscope insertion varies between centres, without a firm rationale based on well-designed studies. We therefore compared nasal and oral insertion of a flexible bronchoscope and evaluated efficacy and patient satisfaction.

DESIGN

Prospective randomised study of patients who underwent flexible bronchoscopy from May to September 2003 and who were randomly assigned to nasal and oral insertion approaches.

RESULTS

Clinical characteristics, factors related to the procedure and patient satisfaction were analysed. In total, 307 patients were randomly assigned to the nasal (n = 158) or oral insertion groups (n = 149). No difference in baseline characteristics was identified between the groups. Insertion by the oral route was associated with a smaller amount of lidocaine use during the procedure (P = 0.04) and less frequent insertion site bleeding (P = 0.005). Patients assigned to oral insertion reported less discomfort during anaesthesia (P = 0.01) and scope insertion (P < 0.001), as well as less dyspnoea (P = 0.04) and coughing (P = 0.03).

CONCLUSION

Oral insertion of a flexible bronchoscope was associated with less discomfort for patients than nasal insertion, although the route of insertion had no significant effect on outcome.

Performance comparison of a continuous-flow stirred-tank reactor and an anaerobic sequencing batch reactor for fermentative hydrogen production depending on substrate concentration

This study was conducted to compare the performance of a continuous-flow stirred-tank reactor (CSTR) and an anaerobic sequencing batch reactor (ASBR) for fermentative hydrogen production at various substrate concentrations. Heat-treated anaerobic sludge was utilized as an inoculum, and hydraulic retention time (HRT) for each reactor was maintained at 12 h. At the influent sucrose concentration of 5 g COD/L, start-up was not successful in both reactors. The CSTR, which was started-up at 10 g COD/L, showed stable hydrogen production at the influent sucrose concentrations of 10-60 g COD/L during 203 days. Hydrogen production was dependent on substrate concentration, resulting in the highest performance at 30 g COD/L. At the lower substrate concentration, the hydrogen yield (based on hexose consumed) decreased with biomass reduction and changes in fermentation products. At the higher substrate concentration, substrate inhibition on biomass growth caused the decrease of carbohydrate degradation and hydrogen yield (based on hexose added). The ASBR showed higher biomass concentration and carbohydrate degradation efficiency than the CSTR, but hydrogen production in the ASBR was less effective than that in the CSTR at all the substrate concentrations.