Prognostic value of dynamic soluble triggering receptor expressed on myeloid cells in bronchoalveolar lavage fluid of patients with ventilator-associated pneumonia

BACKGROUND AND OBJECTIVE

The aim of this study was to investigate the time course, and correlation with prognosis, of BAL fluid concentrations of soluble triggering receptor expressed on myeloid cells (sTREM-1) in patients with ventilator-associated pneumonia (VAP).

METHODS

The study included 35 patients with clinically diagnosed VAP, eight of whom were BAL fluid culture-negative and 27 BAL fluid culture-positive (16 survivors, 11 non-survivors). sTREM-1 levels were measured in BAL fluid of these mechanically ventilated patients, at the time of diagnosis, on days 4-5 and on days 7-9. The time course of this biomarker and its prognostic value for outcome in patients with culture-positive VAP were assessed.

RESULTS

sTREM-1 concentrations were significantly greater in culture-positive VAP patients than in culture-negative VAP patients. sTREM-1 levels decreased significantly with time in surviving patients with culture-positive VAP, but increased significantly with time in non-survivors. In contrast, PaO(2)/fraction of inspired oxygen (FiO(2)) increased significantly with time in survivors and decreased significantly with time in non-survivors. At a cut-off value of -10 pg/mL 7-9 days after initial diagnosis, sTREM levels had a sensitivity of 90% and a specificity of 87.5% for predicting mortality.

CONCLUSIONS

sTREM-1 concentrations in BAL fluid are of potential prognostic value in patients with VAP.

Parametric study of a Hill-type hyperelastic skeletal muscle model

Hill's one-dimensional three-element model has often been used for formulating a three-dimensional skeletal muscle constitutive model, which generally involves several material parameters. However, only few of these parameters have physical meanings and can be experimentally determined. In this paper, a parametric study of a Hill-type hyperelastic skeletal muscle model is performed. First, the Hill-type hyperelastic skeletal muscle model is formulated, containing 13 material parameters. The values or value ranges of these parameters are discussed. The muscle model is then used to predict the behaviour of New Zealand white rabbit hind leg muscle tibialis anterior and a sensitivity study of several parameters is performed. Results show that some parameters in the muscle model can be experimentally determined, some parameters have their own value ranges and the muscle model can predict the experimental data by tuning the parameters within their value ranges. The results from the sensitivity study can help understand how some parameters influence the total muscle stress.

Modelling skeletal muscle fibre orientation arrangement

Skeletal muscle tissues have complex geometries. In addition, the complex fibre orientation arrangement makes it quite difficult to create an accurate finite element muscle model. There are many possible ways to specify the complex fibre orientations in a finite element model, for example defining a local element coordinate system. In this paper, an alternative method using ABAQUS, which is combination of the finite element method and the non-uniform rational B-spline solid representation, is proposed to calculate the initial fibre orientations. The initial direction of each muscle fibre is specified as the tangent direction of the NURBS curve which the fibre lies on, and the directions of the deformed fibres are calculated from the initial fibre directions, the deformation gradients and the fibre stretch ratios. Several examples are presented to demonstrate the ability of the proposed method. Results show that the proposed method is able to characterise both the muscle complex fibre orientation arrangement and its complex mechanical response.

Epitaxial growth and the art of computer simulations

The results of kinetic simulations of the aggregates formed during the deposition of atoms on a semiconductor surface are reviewed. Because the kinetic parameters are poorly known and the accuracy of the existing interatomic potentials has not been sufficiently tested, the goal has been to reach a qualitative understanding of the formation of unusual patterns during growth, such as the segregation of aluminum during the growth of aluminum-gallium-arsenide (AlGaAs) coherent tilted superlattices and the formation of thin, long, and parallel islands during the deposition of Si on an Si(100) surface. Kinetic mechanisms for these phenomena are proposed.

A visco-hyperelastic model for skeletal muscle tissue under high strain rates

In this paper, a visco-hyperelastic skeletal muscle model is developed. The constitutive relation is based on the definition of a Helmholtz free energy function. It is assumed that the Helmholtz energy can be decomposed into volumetric and isochoric parts; furthermore, the isochoric energy can be decoupled into hyperelastic and viscous parts. The model developed involves 14 material parameters and its performance is evaluated by comparing the finite element simulation results with the published experimental studies on the New Zealand white rabbit tibialis anterior muscle. Results show that this model is able to describe the visco-hyperelastic behaviour of both passive and active skeletal muscle tissues under high strain rates (10/s and 25/s).

Immune impairment in patients with terminal cancers: influence of cancer treatments and cytomegalovirus infection

Although immunodeficiency is usually considered a prerequisite of oncogenesis, a detailed immune pro- file in cancer has not yet been described. Without such profiling, it is not surprising that there is a vast discrepancy in the responses of cancer patients to immunotherapy. Our results show that the integrity of the immune system deteriorates with cancer progression by displaying a trend toward decreasing levels of functional T cells, including CD4, naïve, and central memory T cells, and an expansion of hyporesponsive populations such as CD28⁻ and CMV-specific T cells. One hundred and one patients constitute the study group for the observational study reported in this paper. Forty-eight patients with newly diagnosed stages III and IV and 53 patients with extensively treated stage IV disease. The costimulatory molecules CD27 and CD28 were downregulated in all patients. Among the proinflammatory cytokines (IL-6, TNF-α, IFN-γ), only IL-6 differed significantly among the groups, increasing as the cancer stage progressed. Plasma IL-7 did not diVer among the participants. The relative deficits of naïve T cells in cancer patients may be associated with the downregulation of IL-7Rα expression rather than changes in the circulating levels of IL-7. The downregulation of IL-7Rα expression was shown to be associated with increased levels of intracellular CMV. The present study suggests that the immune impairment in patients with cancer is associated with multiple factors, such as the stage of cancer, consequence of CMV infection and impact of treatment.

Bronchodilatation effects of a small volume spacer used with a metered-dose inhaler

BACKGROUND AND OBJECTIVE

In an effort to improve the delivery of drugs to the lungs, various spacer devices have been developed to attach to metered-dose inhalers (MDIs). The aim of the study was to determine whether use of a small volume tube spacer with MDI is associated with better bronchodilatation.

METHODS

We assessed bronchodilatation by measuring forced expiratory volume in 1 second (FEV(1)) before and after inhalation of fenoterol 0.4 mg (2 puffs) delivered by using a MDI in four different ways: with or without a spacer alone or with a mouth rinse of 100 mL of water immediately after inhalation with or without a spacer. Results. A total of 303 patients who had a positive bronchodilator test were studied. There was no significant difference in the Delta FEV(1) (mL or %) with or without a spacer (MDI + spacer vs. MDI, mean +/- SD, 365.1 +/- 146.5 mL vs. 356.3 +/- 131.1 mL, p = 0.696; and 21.4 +/- 9.4% vs. 21.4 +/- 9.5%, p = 0.968, respectively). When patients rinsed their mouth after inhalation, bronchodilatation was significantly less in those using an MDI alone compared with MDI + spacer (302.6 +/- 116.5 mL vs. 367.6 +/- 128.3 mL, p = 0.002; and 18.0% +/- 7.9% vs. 21.7% +/- 9.5%, p = 0.013, respectively).

CONCLUSIONS

When patients correctly use an MDI, addition of a spacer does not significantly improve bronchodilatation. However, if the mouth is rinsed after inhalation, a spacer does yield better bronchodilatation. Our results suggest that systemic effects from bronchodilator inhalation may not be negligible.

IL-10 promoter gene polymorphisms and sustained response to combination therapy in Taiwanese chronic hepatitis C patients

BACKGROUND AND AIMS

Host genetic factors may affect clinical outcomes of hepatitis C virus (HCV) infection; however, the possible mechanisms remain largely unknown. The role of immunopathogenesis in chronic hepatitis C leads to extensive exploration of host immunity including inflammatory cytokines.

METHODS

We examined interleukin 10 (IL-10) promoter gene polymorphisms at positions -1082, -819, and -592 relative to transcription start site and studied their association with response to 24 weeks of pegylated interferon plus ribavirin treatment in 143 chronic hepatitis C patients, of whom 97 (67.8%) achieved a sustained virologic response (SVR). In addition, 134 healthy adults were used as controls.

RESULTS

Of chronic hepatitis C patients, 111 (77.6%) were genotype 1 infection, 32 (22.4%) were genotype 2 infection. Patients with sustained virologic response were younger and had higher pretreatment ALT levels than those without. No statistical difference was found between chronic hepatitis C patients who achieved SVR or not in terms of gender, HCV genotype, pretreatment HCV RNA levels, and severity of liver disease. The serum IL-10 levels were comparable between healthy controls and chronic hepatitis C patients as well as between HCV patients with and without SVR. The distribution of IL-10 promoter gene polymorphisms at positions -1082, -819, and -592 relative to transcription start site was comparable between HCV patients and healthy controls as well as HCV patients with and without SVR. A high frequency of ATA haplotype of common IL-10 promoter gene SNPs was found in both chronic hepatitis C patients (70.3%) and healthy controls (69.8%). However, ATA haplotype was not associated with SVR in chronic hepatitis C patients.

CONCLUSIONS

Our data fail to demonstrate the influence of IL-10 promoter gene polymorphisms on the response to combination therapy in Taiwanese chronic hepatitis C patients. The impact of genetic variations in IL-10 haplotype on the response to anti-HCV treatment among different ethnic populations deserves further examination.

Window-shaped obstacle avoidance for a redundant manipulator

The window-shaped obstacle avoidance problem is studied in this paper. Several research papers regarding obstacle avoidance including the method proposed by Zghal et al., which we believe is the most suitable for three-dimensional (3-D) window-shaped obstacle avoidance are studied. Consequently, several shortcomings of the Zghal's method are discovered. The Zghal's method will produce chattering solution sequences in joint rates due to its deficiency in determining the shortest distance between the manipulator links and the window edges. This paper proposes a new scheme to determine the shortest distance. This new scheme will remedy the chattering problem. Moreover, the nearest link (NL) method is developed for further improvement. Because the NL method only considers the nearest link in the performance criterion, the on-line weighting assignment problem of the Zghal's method is removed, also, less redundancy is required to accomplish the goal for obstacle avoidance. Therefore, the NL method will allow more redundancy to be useful for the other goals under multiple-goal application environments.

Silencing of p29 affects DNA damage responses with UV irradiation

Human p29 is a newly identified nuclear protein whose function is largely undetermined. We found that p29 associated with chromatin, interacted with MCM3, and localized with proliferating cell nuclear antigen foci in the S phase. Silencing of p29 using small interfering RNA duplexes reduced DNA synthesis and increased the expression of p107, a member of the RB family, and of cyclin-dependent kinase inhibitor p21, accompanied with a decreased expression of DNA polymerase alpha. Lethal events consisting of premature chromatin condensation with a reduced Chk1 phosphorylation were observed in p29-depleted cells in response to UV irradiation. Intriguingly, the phosphorylation of ataxia telangectasia-mutated kinases at S1981 was suppressed in p29-depleted HeLa cells with UV irradiation, but not in hydroxyurea- and ionizing radiation-treated cells. Taken together, these results reveal a novel function of p29 in the regulation of DNA replication checkpoint responses.

Triggering receptor expressed on myeloid cells-1 in pleural effusions: a marker of inflammatory disease

BACKGROUND

Triggering receptor expressed on myeloid cells (TREM)-1 is a recently described molecule that plays an important role in myeloid cell-activated inflammatory responses. The aim of this study was to investigate the expression of TREM-1 in pleural effusions of various causes.

METHODS

For this cross-sectional, observational study conducted between February and August 2005 in Taiwan, 74 patients with pleural effusions of varying etiology were investigated. Soluble TREM-1 (sTREM-1) was measured in pleural fluid samples, and cells in the fluid were assessed for surface expression of TREM-1.

RESULTS

Concentrations of sTREM-1 were significantly higher in infectious and neoplastic pleural effusions (189.1+/-36.7 and 69.9+/-22.8ng/ml, mean+/-sem) than in transudates (10.1+/-5.3ng/ml; P<0.001). Among infectious effusions, the sTREM-1 levels were significantly higher in parapneumonic than in tuberculous effusions (301.8+/-49.8 vs. 38.9+/-17.3ng/ml; P<0.001). TREM-1 was expressed on a portion of the myeloid (CD11b positive) cells in each type of effusion, without significant differences among them (transudative, 34.7%; neoplastic, 36.0%; parapneumonic, 27.7%; tuberculous, 21.2%; P=0.861). Non-myeloid cells expressed very little TREM-1 (transudative, 6.3%; neoplastic, 0.5%; parapneumonic, 1.0%; tuberculous, 0.7%; P=0.192).

CONCLUSIONS

sTREM-1 expression in pleural fluids is highest in parapneumonic and neoplastic effusions but low in transudates. In infectious effusions, a high concentration of sTREM-1 may exclude tuberculous pleurisy.

Viral load and outcome in SARS infection: the role of personal protective equipment in the emergency department

This study was conducted to evaluate the effectiveness of personal protective equipment (PPE) against severe acute respiratory syndrome (SARS). Sixteen patients in a SARS cluster, including 4 health care workers (HCWs) and 12 non-HCWs were studied. We compared the initial viral load by nasopharyngeal swabs, clinical progression, and outcome of this cluster. The HCWs had a lower viral load. The non-HCWs had a higher mean C-reactive protein, lower oxygen saturation, and a higher incidence of intubation and death. Secondary household transmission developed in three of the non-HCWs’ families. One month after discharge, non-HCWs had more signs of fibrosis on high resolution computed tomography (HRCT) scan and an impaired pulmonary function test. Although most of the PPE do not confer absolute protection against SARS, it seems that they may lower exposure to the virus, leading to a lower risk of secondary transmission, and be associated with relatively mild disease and a better early outcome.

Preparation and characterization of monoclonal antibody against protein TREM-like transcript-1 (TLT-1)

TREM-like transcript-1 (TLT-1) was initially characterized as the putative inhibitory receptor within the TREM locus on chromosome 6 and was suggested to play a critical role in modulating TREM-associated immunity. Recently, TLT-1 was found not to function as an inhibiting member of the TREM family; however, it may play a significant role in maintaining vascular hemostasis, coagulation, and inflammation at sites of injury through its location in platelets. In this study, we have successfully generated a monoclonal antibody that can be applied to assays, including enzyme-linked immunosorbent assay (ELISA), Western immunoblotting, immunofluorescence, and Fluorescence-Activated Cell Sorter (Becton-Dickinson) (FACS), for the study of TLT-1 functions in physiological and pathological conditions.

Colonization of severe acute respiratory syndrome-associated coronavirus among health-care workers screened by nasopharyngeal swab

STUDY OBJECTIVES

To report the efficacy and findings of a large-scale preventive screening program for severe acute respiratory syndrome-associated coronavirus (SARS-CoV) using amplification of the virus from a nasopharyngeal swab (NPS) obtained from the health-care workers (HCWs).

DESIGN

A prospective observational study.

SETTING

A medical center in Taiwan.

PARTICIPANTS

Two hundred thirty HCWs.

INTERVENTION

NPS examination for the presence of SARS-CoV by two nested reverse transcription-polymerase chain reaction (RT-PCR) assays.

MEASUREMENTS AND RESULTS

During the outbreak of severe acute respiratory syndrome (SARS), NPS polymerase chain reaction screening of HCWs for SARS-CoV was performed. SARS-CoV was examined by two nested RT-PCRs and a quantitative RT-PCR. Serum-specific antibodies were assessed by enzyme immunoassay and indirect immunofluorescence. We monitored 230 HCWs, including 217 first-line HCWs and 13 non-first-line HCWs. One hundred ninety first-line HCWs and 13 non-first-line HCWs had negative results in both nested RT-PCR assays. Two first-line HCWs who were positive on both nested RT-PCR assays had SARS. They had 16,900 +/- 7,920 copies (mean +/- SD) of RNA per milliliter in the NPS and had detectable anti-SARS antibodies. The remaining 25 first-line HCWs were negative for the first nested RT-PCR but positive for the second nested RT-PCR. Their corresponding titers were 338 +/- 227 copies of RNA per milliliter; antibodies developed in none of these 25 HCWs. The expression and function of angiotensin-converting enzyme-2 were not different among these HCWs. This study shows that colonization of SARS-CoV occurred in 25 of 217 well-protected first-line HCWs on a SARS-associated service, but they remained seronegative.

CONCLUSION

With the second RT-PCR assay more sensitive than the first RT-PCR assay, we are able to show that approximately 11.5% of well-protected HCWs exposed to SARS patients or specimens may have colonization without seroconversion. Only those with significant clinical symptoms or disease would have active immunity. Thus, regular NPS screening for nested RT-PCR assays in conjunction with a daily recording of body temperature in all first-line HCWs may provide an effective way of early detection.

Neutralizing antibody response and SARS severity

Using the Taiwan nationwide laboratory-confirmed severe acute respiratory syndrome (SARS) database, we analyzed neutralizing antibody in relation to clinical outcomes. With a linear mixed model, neutralizing antibody titer was shown to peak between week 5 and week 8 after onset and to decline thereafter, with a half-life of 6.4 weeks. Patients with a longer illness showed a lower neutralizing antibody response than patients with a shorter illness duration (p = 0.008). When early responders were compared with most patients, who seroconverted on and after week 3 of illness, the small proportion (17.4%) of early responders (antibody detectable within 2 weeks) had a higher death rate (29.6% vs. 7.8%) (Fisher exact test, p = 0.004), had a shorter survival time of <2 weeks (Fisher exact test, p = 0.013), and were more likely to be > 60 years of age (Fisher exact test, p = 0.01). Our findings have implications for understanding the pathogenesis of SARS and for SARS vaccine research and development.

Adverse effects of ribavirin and outcome in severe acute respiratory syndrome: experience in two medical centers

STUDY OBJECTIVES

To assess the effect of ribavirin-induced anemia on the outcome of severe acute respiratory syndrome (SARS).

DESIGN

A retrospective observational study.

SETTING

Two medical centers in Taiwan.

PATIENTS

Forty-four patients with SARS who received ribavirin and 7 patients with SARS who did not receive ribavirin.

MEASUREMENTS AND RESULTS

The mean peak C-reactive protein and lactate dehydrogenase levels were higher in SARS patients who were receiving ribavirin therapy than in SARS patients who were not receiving ribavirin therapy. The mortality was also higher, but the difference was not statistically significant. On multivariate analysis, hemoglobin level was an independent prognostic correlate of hypoxemia or mortality (odds ratio, 2.0; 95% confidence interval, 1.1 to 3.8; p = 0.03). The hemoglobin began decreasing in two thirds of SARS patients (32 of 44 patients; 73%) who were receiving ribavirin 3 days after therapy with the antiviral drug was started. Patients with a drop in hemoglobin level of > 2 g/dL had a significantly higher mortality rate than the other patients. Hypoxemia developed in one third of SARS patients (17 of 44 patients; 39%) who were receiving ribavirin, all of whom were anemic. Of the 17 hypoxemic patients, 11 (65%) had a drop in hemoglobin of > 2 g/dL, and 4 patients (24%) required a blood transfusion. The mean slope of the hemoglobin decrease was significantly steeper (p = 0.001) in hypoxemic patients with SARS who were receiving ribavirin than in the nonhypoxemic patients with SARS who were receiving ribavirin. Only one of seven SARS patients (14%) who was not receiving ribavirin became anemic, but this individual was not hypoxemic. Eventually, 5 of 17 hypoxemic and anemic SARS patients (29%) who were receiving ribavirin died. The combination of hypoxia with anemia was thus significantly associated with a higher mortality (p < 0.001).

CONCLUSIONS

Hypoxia combined with anemia increased the risk for death in SARS patients. Unless ribavirin can be shown to be effective against SARS-coronavirus, the risk of anemia posed by this drug argues against its use in SARS patients.

Comparative study of patients with and without SARS who fulfilled the WHO SARS case definition

To differentiate severe acute respiratory syndrome (SARS) from non-SARS illness, we retrospectively compared 53 patients with probable SARS and 31 patients with non-SARS who were admitted to Mackay Memorial Hospital from April 27 to June 16, 2003. Fever (> 38°C) was the earliest symptom (50/53 SARS vs. 5/31 non-SARS, p < 0.0001), preceding cough by a mean of 4.5 days. The initial chest X-ray study was normal in 22/53 SARS cases versus 5/31 non-SARS cases. SARS patients with an initially normal chest X-ray study developed infiltrates at a mean of 5 ± 3.44 days after onset of fever (21/22 SARS vs. 0/5 non-SARS). Rapid radiographic progression of unifocal involvement to multifocal infiltrates was seen in 22 of 24 SARS vs. 0 of 26 non-SARS patients (p < 0.0001). Pleural effusion was not present in any SARS patients but was seen in 6 of 26 non-SARS cases (p < 0.0001). Initial lymphopenia, thrombocytopenia, and elevated lactate dehydrogenase were all more common in SARS than non-SARS (p < 0.0001). They may help differentiate SARS from non-SARS if a reliable and rapid diagnostic test is not available.

Clinical and laboratory features of severe acute respiratory syndrome vis-a-vis onset of fever

Study objectives:

Severe acute respiratory syndrome (SARS) is a rapidly progressive disease caused by a novel coronavirus (CoV) infection. However, the disease presentation is nonspecific. The aim of this study was to define clearly the presentation, clinical progression, and laboratory data in a group of patients who had SARS.

Design:

Retrospective observational study.

Setting:

A tertiary care medical center with 51 negative-pressure isolation rooms in Taipei, Taiwan.

Patients:

Fifty-three patients with SARS seen between April 27 and June 16, 2003.

Results:

Fever (ie, temperature > 38°C) was the most common symptom (98%) and the earliest. When admitted to the isolation unit of the hospital for observation, most patients reported nonspecific symptoms associated with their fever. Only two patients with preexisting illnesses had cough on the same day the fever began. Eventually, 39 patients (74%) developed cough, beginning at a mean (± SD) time of 4.5 ± 1.9 days after fever onset, and 35 patients (66%) had diarrhea beginning at a mean time of 6.0 ± 3.3 days after fever onset. Thirty-one patients (59%) had abnormal findings on chest radiographs on hospital admission, and all but 1 patient (98%) eventually developed lung infiltrates that were consistent with pneumonia. The majority of patients (63%) first developed unifocal infiltrates at a mean time of 4.5 ± 2.1 days after fever onset, while in 37% of patients the initial infiltrates were multifocal, appearing at a mean time of 5.8 ± 1.3 days after fever onset. Common laboratory findings included lymphopenia (on hospital admission, 70%; during hospitalization, 95%), thrombocytopenia (on hospital admission, 28%; during hospitalization, 40%), elevated lactate dehydrogenase (on hospital admission, 58%; during hospitalization, 88%), creatine kinase (on hospital admission, 18%; during hospitalization, 32%), and aspartate aminotransferase or alanine aminotransferase levels (on hospital admission, 27%; during hospitalization, 62%). Throat or nasopharyngeal swab for SARS-CoV by reverse transcriptase polymerase chain reaction (PCR) and real-time PCR was positive in 40 of the 47 patients (85%) in whom the test was performed.

Conclusions:

None of the presenting symptoms or laboratory findings are pathognomonic for SARS. Even though cough developed in a majority of patients, it did not occur until later in the disease course, suggesting that a cough preceding or concurrent with the onset of fever is less likely to indicate SARS. While PCR for SARS-CoV appears to be the best early diagnostic test currently available, it is clear that better methods are needed to differentiate between SARS and non-SARS illness on initial presentation.