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1.
Environ Sci Technol ; 58(16): 6868-6877, 2024 Apr 23.
Article in English | MEDLINE | ID: mdl-38593035

ABSTRACT

Bioaerosols play a significant role in the transmission of many infectious diseases, especially in enclosed indoor environments. Ultraviolet (UV) disinfection has demonstrated a high efficacy in inactivating microorganisms suspended in the air. To develop more effective and efficient UV disinfection protocols, it is necessary to evaluate and optimize the effectiveness of UV disinfection against aerosolized bacteria and viruses across the entire UV spectrum. In this study, we evaluated the performance of UV disinfection across the UV spectrum, ranging from 222 to 365 nm, against aerosolized bacteria and viruses, including Escherichia coli, Staphylococcus epidermidis, Salmonella enterica, MS2, P22, and Phi6. Six commonly available UV sources, including gas discharge tubes and light-emitting diodes with different emission spectra, were utilized, and their performance in terms of inactivation efficacy, action spectrum, and energy efficiency was determined. Among these UV sources, the krypton chloride excilamp emitting at a peak wavelength of 222 nm was the most efficient in inactivating viral bioaerosols. A low-pressure mercury lamp emitting at 254 nm performed well on both inactivation efficacy and energy efficiency. A UV light-emitting diode emitting at 268 nm demonstrated the highest bacterial inactivation efficacy, but required approximately 10 times more energy to achieve an equivalent inactivation level compared with that of the krypton chloride excilamp and low-pressure mercury lamp. This study provides insights into UV inactivation on bioaerosols, which can guide the development of effective wavelength-targeted UV air disinfection technologies and may significantly help reduce bioaerosol transmission in public areas.

2.
J Hazard Mater ; 441: 129876, 2023 01 05.
Article in English | MEDLINE | ID: mdl-36087531

ABSTRACT

Air ionizers and 222-nm krypton-chlorine (KrCl) excilamp have proven to be effective disinfection apparatus for bacteria and viruses with limited health risks. We determined inactivation efficiencies by operating them individually and in combined modules. Gram-positive and gram-negative bacteria, non-enveloped dsDNA virus, and enveloped dsRNA virus were examined in a designed air disinfection system. Our results showed that the bioaerosols were inactivated efficiently by negative ionizers and far-UVC (222-nm), either used individually or in combination. Among which the combined modules of negative ionizers and KrCl excilamp had the best disinfection performance for the bacteria. The aerosolized virus P22 and Phi 6 were more susceptible to 222-nm emitted by KrCl excilamp than negative air ions. Significant greater inactivation of bacterial bioaerosols were identified after treated by combined treatment of negative air ion and far-UVC for 2 minutes (Escherichia coli, 6.25 natural log (ln) reduction; Staphylococcus epidermidis, 3.66 ln reduction), as compared to the mean sum value of inactivation results by respective individual treatment of negative ionizers and KrCl excilamp (Escherichia coli, 4.34 ln; Staphylococcus epidermidis, 1.75 ln), indicating a synergistic inactivation effect. The findings provide important baseline data to support the design and development of safe and high-efficient disinfection systems.


Subject(s)
Bacteriophages , Escherichia coli O157 , Viruses , Anti-Bacterial Agents , Bacteria , Chlorine , Disinfection/methods , Gram-Negative Bacteria , Gram-Positive Bacteria , Ions , Krypton , Salmonella typhimurium
3.
Public Health ; 188: 42-50, 2020 Nov.
Article in English | MEDLINE | ID: mdl-33075669

ABSTRACT

OBJECTIVES: The novel coronavirus disease 2019 (COVID-19) epidemic that emerged in December 2019 has rapidly evolved in recent months to become a worldwide and ongoing pandemic. Shortage of medical masks remains an unresolved problem. This study aims to investigate the filtration efficiency (FE) of home-made masks that could be used as alternatives for community mitigation of COVID-19. STUDY DESIGN: Experimental observational analytic study. METHODS: The FE of home-made masks and medical masks (as the control) were tested under laminar flow within a scaled air duct system using nebulised NaCl aerosols sized 6-220 nm. The size-resolved NaCl aerosol count was measured using a scanning mobility particle-sizer spectrometer. Home-made masks with an external plastic face shield also underwent a splash test. In addition, the fibre structures of medical masks were studied under an electron microscope after treatment with either 75% alcohol or soap and water at 60 °C. RESULTS: The FE of the home-made masks at 6-200 nm were non-inferior to that of medical masks (84.54% vs 86.94%, P = 0.102). Both types of masks achieved an FE of 90% at 6-89 nm. A significantly higher FE was achieved when one piece of tissue paper was added adjacent to the inner surface of the medical mask than medical mask alone (6-200 nm: 91.64% vs 86.94%, P < 0.0001; 6-89 nm: 94.27% vs 90.54%, P < 0.0001; 90-200 nm: 82.69% vs 73.81%, P < 0.0001). The plastic face shield prevented the home-made mask from fluid splash. The fibre structures of the external surface of medical masks were damaged after treatment with either 75% alcohol or soap and water at 60 °C. CONCLUSIONS: The home-made masks in this study, which were made of one piece of tissue paper and two pieces of kitchen towels, layered from face to external, had an FE at 6-200 nm non-inferior to that of medical mask materials, which had a certified FE of ≥95% at 3 µm. In the current COVID-19 pandemic with the shortage of medical masks, these home-made masks combined with an external plastic shield could be used as an alternative to medical masks for community mitigation. In addition, one piece of tissue paper could be placed adjacent to the inner surface of a medical mask to prolong effective lifespan of the medical mask. These demand reduction strategies could be used to reserve medical masks for use in healthcare and certain high-risk community settings, such as symptomatic persons, caregivers and attendees to healthcare institutions.


Subject(s)
Coronavirus Infections/prevention & control , Filtration/standards , Masks/standards , Pandemics/prevention & control , Pneumonia, Viral/prevention & control , Aerosols , COVID-19 , Coronavirus Infections/epidemiology , Humans , Nanoparticles , Pneumonia, Viral/epidemiology
4.
J Hazard Mater ; 358: 389-396, 2018 09 15.
Article in English | MEDLINE | ID: mdl-30005250

ABSTRACT

The process of toilet-flushing can generate flushing-associated water droplets which can potentially expose humans to pathogen-laden aerosols. Very little is known about such aerosol dissemination or the means for minimizing exposure to these aerosols. This study has evaluated the efficacy of ultraviolet waveband C (UV-C) for disinfection of flushing-generated pathogen-laden aerosols through tests with localized disinfection systems for airborne and surface contaminations. Three types of bacteria were chosen for investigation: Staphylococcus epidermidis, Escherichia coli, and Salmonella typhimurium. Tests were conducted with UV-C tubes of 5 W and 10 W. High levels of disinfection efficacies were observed, ranging from 76% to 97% for bacteria-laden aerosols at sources of emission, and efficiencies of 53% to 79% for surface samples in localized systems. The results from the localized systems were further compared with those obtained with an upper-room ultraviolet germicidal irradiation (UVGI) system. As it is important to note, the UV-C doses and ozone emissions for the localized systems were found well below the limits recommended in current guidelines. This research has shown that the disinfection of flushing-generated pathogen-laden aerosols in proximity to the source of emission was more effective than at the more distant sites where aerosols may be dispersed to the environment.


Subject(s)
Air Microbiology/standards , Disinfection/methods , Toilet Facilities/standards , Ultraviolet Rays , Aerosols , Air Pollution, Indoor/prevention & control , Escherichia coli/radiation effects , Pilot Projects , Salmonella typhimurium/radiation effects , Staphylococcus epidermidis/radiation effects
5.
Indoor Air ; 28(1): 73-79, 2018 Jan.
Article in English | MEDLINE | ID: mdl-28683156

ABSTRACT

The flushing of toilets generates contaminated aerosols, the transmission of which may cause the spread of disease, particularly in the immunocompromised or the elderly. This study investigated the emission strength of three types of airborne bacteria, namely Staphylococcus epidermidis, Escherichia coli, and Pseudomonas alcaligenes, during toilet flushing in a custom-built toilet under a controlled environment. Flushing was activated by a flushometer operated at two pressure levels, 400 kPa (high pressure [HP]) and 200 kPa (low pressure [LP]), and by a water cistern tank placed 95 cm (high tank [HT]) and 46 cm (low tank [LT]) above the toilet seat. The pathogens emitted by the first flush were calculated, with the correlations between airborne pathogen emissions and droplet concentration (HP, r=0.944, P<.001; LP, r=0.803, P<.001, HT, r=0.885, P<.05) and bacterial size (HP, r=-0.919, P<.001; LP, r=-0.936, P<.001; HT, r=-0.967, P<.05) in the different conditions then tested. The emission strength in the HP condition was statistically greater than that in the LP condition, whereas the cistern tank system produced less emissions than the flushometer system, and tank height was not found to be a sensitive parameter.


Subject(s)
Air Microbiology , Toilet Facilities , Aerosols
6.
Int J Law Psychiatry ; 54: 61-66, 2017.
Article in English | MEDLINE | ID: mdl-28528124

ABSTRACT

Mapping forensic psychiatric services with the security needs of patients is a salient step in service planning, audit and review. A valid and reliable instrument for measuring the security needs of Chinese forensic psychiatric inpatients was not yet available. This study aimed to develop and validate the Chinese version of the Security Needs Assessment Profile for measuring the profiles of security needs of Chinese forensic psychiatric inpatients. The Security Needs Assessment Profile by Davis was translated into Chinese. Its face validity, content validity, construct validity and internal consistency reliability were assessed by measuring the security needs of 98 Chinese forensic psychiatric inpatients. Principal factor analysis for construct validity provided a six-factor security needs model explaining 68.7% of the variance. Based on the Cronbach's alpha coefficient, the internal consistency reliability was rated as acceptable for procedural security (0.73), and fair for both physical security (0.62) and relational security (0.58). A significant sex difference (p=0.002) in total security score was found. The Chinese version of the Security Needs Assessment Profile is a valid and reliable instrument for assessing the security needs of Chinese forensic psychiatric inpatients.


Subject(s)
Forensic Psychiatry/instrumentation , Needs Assessment , Surveys and Questionnaires/standards , Adult , Aged , Cross-Sectional Studies , Factor Analysis, Statistical , Female , Hong Kong/epidemiology , Hospitals, Psychiatric , Humans , Inpatients , Male , Mental Disorders/epidemiology , Mental Disorders/therapy , Middle Aged , Needs Assessment/standards , Psychometrics , Reproducibility of Results , Sex Factors , Translating , Violence , Young Adult
7.
Cell Death Dis ; 5: e1518, 2014 Nov 13.
Article in English | MEDLINE | ID: mdl-25393474

ABSTRACT

T-cell receptor (TCR)-transduced signaling is critical to thymocyte development at the CD4/CD8 double-positive stage, but the molecules involved in this process are not yet fully characterized. We previously demonstrated that GM-CSF/IL-3/IL-5 receptor common ß-chain-associated protein (CBAP) modulates ZAP70-mediated T-cell migration and adhesion. On the basis of the high expression of CBAP during thymocyte development, we investigated the function of CBAP in thymocyte development using a CBAP knockout mouse. CBAP-deficient mice showed normal early thymocyte development and positive selection. In contrast, several negative selection models (including TCR transgene, superantigen staphylococcal enterotoxin B, and anti-CD3 antibody treatment) revealed an attenuation of TCR-induced thymocyte deletion in CBAP knockout mice. This phenotype correlated with a reduced accumulation of BIM upon TCR crosslinking in CBAP-deficient thymocytes. Loss of CBAP led to reduced TCR-induced phosphorylation of proteins involved in both proximal and distal signaling events, including ZAP70, LAT, PLCγ1, and JNK1/2. Moreover, TCR-induced association of LAT signalosome components was reduced in CBAP-deficient thymocytes. Our data demonstrate that CBAP is a novel component in the TCR signaling pathway and modulates thymocyte apoptosis during negative selection.


Subject(s)
Gene Expression Regulation, Developmental , Membrane Proteins/genetics , Receptors, Antigen, T-Cell/genetics , Signal Transduction/genetics , Thymocytes/metabolism , Adaptor Proteins, Signal Transducing/genetics , Adaptor Proteins, Signal Transducing/metabolism , Animals , Apoptosis/genetics , Apoptosis Regulatory Proteins/genetics , Apoptosis Regulatory Proteins/metabolism , Bcl-2-Like Protein 11 , Cell Adhesion , Cell Differentiation , Cell Movement , Female , Male , Membrane Proteins/deficiency , Membrane Proteins/metabolism , Mice , Mice, Knockout , Mitogen-Activated Protein Kinase 8/genetics , Mitogen-Activated Protein Kinase 8/metabolism , Mitogen-Activated Protein Kinase 9/genetics , Mitogen-Activated Protein Kinase 9/metabolism , Phospholipase C gamma/genetics , Phospholipase C gamma/metabolism , Phosphoproteins/genetics , Phosphoproteins/metabolism , Phosphorylation , Proto-Oncogene Proteins/genetics , Proto-Oncogene Proteins/metabolism , Receptors, Antigen, T-Cell/metabolism , Thymocytes/cytology , Thymus Gland/cytology , Thymus Gland/growth & development , Thymus Gland/metabolism , ZAP-70 Protein-Tyrosine Kinase/genetics , ZAP-70 Protein-Tyrosine Kinase/metabolism
8.
J Aerosol Sci ; 63: 10-24, 2013 Sep.
Article in English | MEDLINE | ID: mdl-32287375

ABSTRACT

The three-dimensional multiple-relaxation-time LB (MRT-LB) and Lagrangian particle tracking methods were applied to simulate turbulent airflow and particle dispersion in a ventilated room with a partition. The turbulent airflow was simulated by large eddy simulation (LES) using the MRT-LB method with the Smagorinsky model. This method was verified by comparing it with experimental and other numerical results. Good agreement was observed between airflow simulation and experimental data. It is also demonstrated that the LES carried out by the MRT-LB method can produce airflow results very similar to the RNG LES and provide better prediction than the standard and RNG k-ε models. In order to further improve the efficiency of the MRT-LB method, the multi-block grid refinement (MBGR) technique was used. The accuracy and efficiency of the MBGR and the consistency of physical quantities across the interface were investigated. In simulation of particle dispersion in the model room, particles with diameters of 1 and 10 µm were considered. It is shown that this model can successfully capture dispersion characteristics of particles.

9.
J R Soc Interface ; 9(77): 3184-95, 2012 Dec 07.
Article in English | MEDLINE | ID: mdl-22809847

ABSTRACT

There has been increasing interest in the use of upper-room ultraviolet germicidal irradiation (UVGI) because of its proven effectiveness in disinfecting airborne pathogens. An improved drift flux mathematical model is developed for optimizing the design of indoor upper-room UVGI systems by predicting the distribution and inactivation of bioaerosols in a ventilation room equipped with a UVGI system. The model takes into account several bacteria removal mechanisms such as convection, turbulent diffusion, deposition and UV inactivation. Before applying the model, the natural die-off rate and susceptibility constants of bioaerosols were measured experimentally. Two bacteria aerosols, Escherichia coli and Serratia marcescens, were tested for this purpose. It was found out that the general decay trend of the bioaerosol concentration predicted by the numerical model agrees well with the experimental measurements. The modelling results agree better with experimental observations for the case when the UVGI inactivation mechanism dominates at the upper-room region than for the case without UVGI. The numerical results also illustrate that the spatial distribution of airborne bacteria was influenced by both air-flow pattern and irradiance distribution. In addition to predicting the local variation of concentration, the model assesses the overall performance of an upper-room UVGI system. This model has great potential for optimizing the design of indoor an upper-room UVGI systems.


Subject(s)
Aerosols/analysis , Air Microbiology , Disinfection/methods , Environmental Exposure/prevention & control , Escherichia coli/isolation & purification , Serratia marcescens/isolation & purification , Ultraviolet Rays , Environment, Controlled , Escherichia coli/radiation effects , Models, Theoretical , Serratia marcescens/radiation effects , Ventilation
10.
J R Soc Interface ; 9(70): 938-48, 2012 May 07.
Article in English | MEDLINE | ID: mdl-21937487

ABSTRACT

Facemasks are widely used as a protective measure by general public to prevent inhalation of airborne pathogens including seasonal, swine and other forms of influenza and severe acute respiratory syndrome (SARS), etc. However, scientific data on effectiveness of facemasks in reducing infections in the community are extremely limited and even inconsistent. In this work, two manikins labelled as 'source' and 'susceptible' were used to measure the protection provided by facemasks under various emission scenarios. The source was modified to generate polydisperse ultrafine particles, whereas the susceptible was modified to mimic a realistic breathing pattern. The facemask was challenged by both pseudo-steady and highly transient emissions generated by an expiratory process where parameters, such as separation distance between manikins, emission velocity and expiratory duration, were controlled and measured systematically. Performances of four different types of facemask fits, varying from ideal to normal wearing practice, were also investigated. Under the pseudo-steady concentration environment, facemask protection was found to be 45 per cent, while under expiratory emissions, protection varied from 33 to 100 per cent. It was also observed that the separation between the source and the manikin was the most influential parameter affecting facemask protection.


Subject(s)
Air Microbiology , Communicable Disease Control/instrumentation , Inhalation Exposure , Masks , Aerosols , Communicable Disease Control/methods , Humans , Pulmonary Ventilation , Respiration , Time Factors
11.
J Hazard Mater ; 189(1-2): 173-85, 2011 May 15.
Article in English | MEDLINE | ID: mdl-21377783

ABSTRACT

There has been an increasing interest in the use of upper-room ultraviolet germicidal irradiation (UVGI) system because of its proven disinfection effect for airborne microorganisms. To better design and explore further potential applications of UVGI systems, it is of critical importance to predict the spatial UV intensity in enclosures. In this paper, we developed a new mathematical model to predict spatial radiation intensity for upper-room ultraviolet germicidal irradiation systems. The detail geometries of the lamp and the reflector were removed and replaced by introducing a fictitious irradiation surface near louver slots. The view factor approach was applied to evaluate the UV irradiance in a three-dimensional space with different louver configurations. With this approach no detail meshing of the fixture is required and this leads to significant simplification of the entire systems from modeling perspectives. To validate the model, experiments were performed in a full-scale environmental controlled chamber in which one UVGI fixture was mounted on a sidewall. The UV irradiance was measured by a radiometer. The results predicted by the present model agree very well with the experimental measurements. Factors affect the accuracy of the model was also discussed.


Subject(s)
Air Pollution, Indoor/prevention & control , Disinfection/methods , Infection Control/methods , Models, Theoretical , Ultraviolet Rays , Air Microbiology , Disinfection/instrumentation , Environment, Controlled , Infection Control/instrumentation
12.
FEMS Microbiol Lett ; 215(1): 133-8, 2002 Sep 24.
Article in English | MEDLINE | ID: mdl-12393213

ABSTRACT

Zoocin A is a lysostaphin-like streptococcolytic enzyme produced by Streptococcus equi subsp. zooepidemicus 4881 that specifically targets the cell walls of some closely related species. On the basis of sequence homology it was suggested that zoocin A was a domain-structured enzyme with the N-terminal domain responsible for catalysis (CAT) and the C-terminal domain for target recognition (SBD). Polypeptides corresponding to zoocin A (rZooA) and each of the putative domains (rCAT and rSBD) were prepared by use of recombinant technology. The biological activities of each was compared by use of a dye-release assay and a cell-binding assay. Cell wall hydrolysis was shown to be a function of CAT and target recognition a function of the SBD. Expression of the zoocin A immunity factor gene produced cell walls resistant to hydrolysis by either rZooA or its component domains, and with reduced capacity to bind rZooA and rSBD.


Subject(s)
Bacterial Proteins/chemistry , Bacterial Proteins/metabolism , Streptococcus equi/enzymology , Catalysis , Hydrolysis , Lysostaphin/metabolism , Protein Structure, Tertiary , Recombinant Proteins , Substrate Specificity
13.
Br J Sports Med ; 36(1): 69-70, 2002 Feb.
Article in English | MEDLINE | ID: mdl-11867498

ABSTRACT

The case is reported of an athlete who, during an exercise test, had a complete atrioventricular block without symptoms of cardiac output failure. Heart rate, stroke index, cardiac index, and myocardial contractility were monitored during the episode by an impedance cardiograph. The most important findings of this report are the continuous increase in stroke index, which compensated for the lack of heart rate response, and the normal cardiac index values achieved during the exercise. This stroke index response was mainly due to an increase in myocardial contractility.


Subject(s)
Exercise/physiology , Heart Block/physiopathology , Hemodynamics , Adult , Exercise Test , Football/physiology , Heart Block/diagnosis , Heart Rate , Humans , Male , Myocardial Contraction/physiology , Stroke Volume
14.
Indoor Air ; 12(4): 211-4, 2002 12.
Article in English | MEDLINE | ID: mdl-12532752

ABSTRACT

Particle deposition indoors has received increasing attention recently because of increasing concern about the effects of particle exposure on human health. Deposition is a positive phenomenon from the perspective of human health, as deposited particles cannot be inhaled unless resuspended. There are studies showing strong correlation between the prevalence of biological-origin airborne particles and the prevalence of some specific sick building syndrome (Menzies et al., 1998; Teeuw et al., 1994). In the literature, the amount of research effort put on particle deposition indoors which is directly related to human health and microcontamination control is far less than the amount of research on deposition in small diameter tube/channel. This is a summary of the full-length version which will appear on the home page. The full-length paper aims to provide an up-to-date revision for both experiment and modeling on particle deposition indoors. This paper summarizes the experimental studies for particle deposition indoors for non-industrial environments. In section 2, 'Background', an overview of the different mechanisms of particle deposition, focusing on indoor environments is addressed. In section 3, 'Experimental Study Review', a survey of aerosol deposition experiments in small experimental chambers and real houses (or large-scale chambers) is presented. Detailed experimental measurements are addressed for the real house studies. The experimental techniques of particle generation, particle labeling and detection methods are discussed. Although the present paper focuses on experimental studies, it would be more complete to include some discussions on the modeling of the term particle eddy diffusivity and it is reviewed in section 4, 'Modeling Review'.


Subject(s)
Air Pollution, Indoor/analysis , Environmental Exposure , Inhalation Exposure , Models, Theoretical , Air Movements , Diffusion , Environmental Monitoring , Humans , Particle Size , Public Health
15.
Aliment Pharmacol Ther ; 15(12): 1913-9, 2001 Dec.
Article in English | MEDLINE | ID: mdl-11736722

ABSTRACT

BACKGROUND: Helicobacter pylori infection has been suggested to be protective against gastro-oesophageal reflux disease. However, a significant proportion of patients with gastro-oesophageal reflux disease are infected by H. pylori. AIM: To study oesophageal motor function in H. pylori-infected patients with reflux oesophagitis. METHODS: Patients with erosive reflux oesophagitis were recruited prospectively for stationary oesophageal manometry and 24-h ambulatory oesophageal pH monitoring. H. pylori status was determined by biopsy urease test. Non-reflux volunteers were recruited as controls. RESULTS: Seventy-four patients with erosive oesophagitis (34 H. pylori-positive, 40 H. pylori-negative) and 48 non-reflux patient controls (22 H. pylori-positive, 26 H. pylori-negative) were recruited. There was no difference in severity of oesophagitis (median grade, 1; P=0.53) or oesophageal acid exposure (total percentage time oesophageal pH < 4, 7.6% vs. 6.8%; P=0.57) between H. pylori-positive and H. pylori-negative groups. Compared to H. pylori-negative patients, H. pylori-positive patients had significantly lower basal lower oesophageal sphincter pressure (12.2 mmHg vs. 15.3 mmHg; P=0.03) and amplitude of distal peristalsis (56.9 mmHg vs. 68.4 mmHg; P=0.03). Ineffective oesophageal motility (14% vs. 7%; P=0.02) and failed oesophageal peristalsis were also significantly more prevalent in H. pylori-positive patients. CONCLUSIONS: Among patients with a similar degree of reflux oesophagitis, H. pylori-infected patients have more severe oesophageal dysmotility and lower oesophageal sphincter dysfunction. Oesophageal motor dysfunction probably plays a dominant role in the development of gastro-oesophageal reflux disease in patients with H. pylori infection.


Subject(s)
Esophagitis, Peptic/physiopathology , Gastroesophageal Reflux/physiopathology , Helicobacter Infections/physiopathology , Helicobacter pylori , Adult , Aged , Esophagitis, Peptic/microbiology , Female , Gastritis/microbiology , Gastritis/physiopathology , Gastroesophageal Reflux/microbiology , Helicobacter Infections/microbiology , Humans , Male , Middle Aged
16.
Arch Virol ; 146(6): 1063-74, 2001.
Article in English | MEDLINE | ID: mdl-11504416

ABSTRACT

We reported previously that equine-2 influenza A virus (H3N8) had evolved into two genetically and antigenically distinct "Eurasian" and "American" lineages. Phylogenetic analysis, using the HA1 gene of more recent American isolates, indicated a further divergence of these viruses into three evolution lineages: A South American lineage, a Kentucky lineage, and a Florida lineage. These multiple evolution pathways were not due to geographic barriers, as viruses from different lineages co-circulated. For the Kentucky lineage, the evolution rate was estimated to be 0.89 amino acid substitutions per year, which agreed with the previously estimated rate of 0.8. For the South American lineage, the evolution rate was estimated to be only 0.27 amino acid substitutions per year. This low evolution rate was probably due to a unique alternating Ser138 to Ala138 substitutions at antigenic site A. For the Kentucky lineage, there was a preference for sequential nonsynonymous substitutions at antigenic site B, which was also a "hot spot" for amino acid substitutions. Convalescent sera had minimal cross-reactivity to viruses of different lineages, indicating antigenic distinctions among these viruses. In contrast to human H3N2 viruses, our results suggested that the evolution of equine-2 influenza virus resembled the multiple evolution pathways of influenza B virus.


Subject(s)
Evolution, Molecular , Influenza A Virus, H3N8 Subtype , Influenza A virus/genetics , Amino Acid Sequence , Amino Acid Substitution , Animals , Antigens, Viral/genetics , Florida , Genes, Viral , Hemagglutinins, Viral/genetics , Horses , Humans , Influenza A virus/classification , Influenza A virus/immunology , Influenza A virus/isolation & purification , Kentucky , Molecular Sequence Data , South America , Time Factors , Viral Proteins/genetics , Viral Proteins/immunology
17.
Gastrointest Endosc ; 54(3): 340-5, 2001 Sep.
Article in English | MEDLINE | ID: mdl-11522975

ABSTRACT

BACKGROUND: Bacteria play an important role in the formation of brown pigment stones through adherence and biofilm formation. Scanning electron microscopy of cross sections of these stones reveals a laminated appearance and various bacteria in the different layers. Our postulation was that different bacteria might be involved at different stages of stone formation. METHODS: By using standard bacteriologic cultures, the composition, morphology, and antibiotic sensitivity patterns of bacteria isolated from paired stone were compared with bile samples from 70 patients with acute cholangitis. A further comparison was made between bacteria isolated from the periphery and center of 3 randomly selected brown pigment stones. RESULTS: Ninety-one percent of bile and 99% of stone samples yielded positive cultures, with a total of 151 and 149 bacteria isolated from bile and stones, respectively. In 22 patients (33%), the bacteria isolated from the paired bile and stone samples were totally different. The mean percentage similarity of bacteria isolated from bile and stones was 39% (range 0%-100%). Of the 59 pairs of similar bacteria isolated, the antibiotic sensitivity patterns were different in 24 (41%) cases. Of the 3 brown stones studied, either different bacterial species or the same bacteria but different strains with different antibiotic sensitivities were isolated from the center and periphery of the stones. CONCLUSIONS: Bacteria present in the different layers of brown pigment stones may represent the bacterial flora in bile at different times. Simple bile culture may not identify bacteria trapped inside the stone.


Subject(s)
Bile/microbiology , Cholangitis/microbiology , Cholelithiasis/chemistry , Cholelithiasis/microbiology , Bile Pigments/analysis , Cholangitis/metabolism , Female , Glucuronidase/analysis , Humans , Male , Microbial Sensitivity Tests , Microscopy, Electron, Scanning , Middle Aged
18.
Circ Res ; 88(8): 839-48, 2001 Apr 27.
Article in English | MEDLINE | ID: mdl-11325877

ABSTRACT

The intramural dynamics of ventricular fibrillation (VF) remain poorly understood. Recent investigations have suggested that stable intramural reentry may underlie the mechanisms of VF. We performed optical mapping studies of VF in isolated swine right ventricles (RVs) and left ventricles (LVs). Nine RV walls were cut obliquely in their distal edge exposing the transmural surface. Six LV wedge preparations were also studied. Results showed that intramural reentry was present. In RV, 28 of 44 VF episodes showed reentry; 15% of the activation pathways were reentrant. Except for 4 episodes, reentry was transmural, involving subendocardial structures as the papillary muscle (PM) or trabeculae. In LV, reentry was observed in 27 of 27 VF episodes; 23% of the activations were part of reentrant pathways (P<0.05 compared with RV). All LV reentrant pathways were truly intramural (confined to the wall) and were frequently located at the PM insertion. In both ventricles, reentry was spatially and temporally unstable. Histological studies showed abrupt changes in fiber orientation at sites of reentry and wave splitting. Connexin 40 immunostaining demonstrated intramyocardial Purkinje fibers at sites of reentry in the PM root and around endocardial trabeculae. Our results confirm that reentry is frequent-but unstable-in the myocardial wall during VF. In RV, reentry is mostly transmural and requires participation of subendocardial structures. The LV has a greater incidence of reentry and is intramural. Anisotropic anatomic structures played key roles in the generation of wave splitting and in the maintenance of reentry.


Subject(s)
Heart Conduction System/physiopathology , Heart Ventricles/physiopathology , Ventricular Fibrillation/physiopathology , Animals , Anisotropy , Body Surface Potential Mapping , Connexins/metabolism , Electrophysiologic Techniques, Cardiac , In Vitro Techniques , Myocardium/metabolism , Optics and Photonics , Papillary Muscles/physiopathology , Purkinje Fibers/metabolism , Swine , Ventricular Dysfunction, Left/physiopathology , Ventricular Dysfunction, Right/physiopathology , Gap Junction alpha-5 Protein
19.
Aliment Pharmacol Ther ; 15(1): 19-24, 2001 Jan.
Article in English | MEDLINE | ID: mdl-11136274

ABSTRACT

BACKGROUND: Prophylactic misoprostol or non-steroidal anti-inflammatory drugs (NSAIDs) with low gastric toxicity (nabumetone) has been shown to reduce mucosal injury. AIM: To compare nabumetone vs. co-therapy of naproxen with low-dose misoprostol for secondary prevention of upper gastrointestinal bleeding in NSAID users. METHODS: NSAID users presenting with upper gastrointestinal bleeding were enrolled if they required long-term NSAIDs. After ulcer healing, they were randomized to receive: naproxen (500-1000 mg/day) and misoprostol (200 microg b.d.), or nabumetone (1000-1500 mg/day) and placebo misoprostol for 24 weeks. The primary end-point was recurrent upper gastrointestinal bleeding. The secondary end-point was the proportion of patients suffering from major gastrointestinal events including ulcer bleeding, symptomatic ulcers and severe dyspepsia. RESULTS: A total of 90 patients were included in the intention-to-treat analysis (misoprostol/naproxen 45, nabumetone 45). Recurrent bleeding occurred in 10 patients (22.2%) receiving misoprostol/naproxen compared with three (6.7%) receiving nabumetone (relative risk 3.33, 95% CI: 0.98-11.32, P=0.069). The proportion of patients suffering from major gastrointestinal events at 24 weeks was 31.1% in the misoprostol/naproxen group and 28.9% in the nabumetone group. CONCLUSIONS: Misoprostol/naproxen is not superior to nabumetone for secondary prevention of upper gastrointestinal bleeding. Neither low-dose misoprostol nor nabumetone is adequate for high-risk NSAID users.


Subject(s)
Anti-Inflammatory Agents, Non-Steroidal/adverse effects , Butanones/therapeutic use , Gastrointestinal Hemorrhage/prevention & control , Misoprostol/administration & dosage , Naproxen/administration & dosage , Adult , Aged , Aged, 80 and over , Drug Therapy, Combination , Female , Gastrointestinal Hemorrhage/chemically induced , Humans , Male , Middle Aged , Nabumetone , Prospective Studies , Recurrence
20.
J Pers ; 69(6): 925-53, 2001 Dec.
Article in English | MEDLINE | ID: mdl-11767824

ABSTRACT

A brief intellectual history of the indigenization movement in Asia leads to the thesis that the generation of psychological knowledge is culture dependent. Indigenous psychologies go further and insist on viewing a target group from the natives' own standpoint. Psychological decentering underlies conceptions of human existence rooted in Asian intellectual traditions, in particular, relatedness between persons predominates in Confucianism. These conceptions demand new approaches to knowledge generation that signify a paradigmatic shift from methodological individualism to methodological relationalism. An implication is that relationships precede situations in the study of personality and social behavior. We define personality as the sum total of common attributes manifest in, and abstracted from, a person's behavior directly or indirectly observed across interpersonal relationships and situations over time. We rely on the notion that there are identifiable levels of cognition to develop a metatheoretical framework for reconstructing selfhood. Confronting the subject-object dichotomy opens the door to investigations of transcendent consciousness; confronting the self-other demarcation underlying Western theories leads to the construction of self-in-relations.


Subject(s)
Culture , Ethnicity , Personality , Cross-Cultural Comparison , Humans , Psychological Theory
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