Are there "CO2 sensors" in the lung?
Explore the source record for details and available documents.
Animals↗
Biomedical subjects
L Y Lee
Publications and source records attributed to L Y Lee.
Novel brain reactive autoantibodies: prevalence in systemic lupus erythematosus and association with psychoses and seizures.
Autoantibodies can cause neuropsychiatric manifestations in lupus patients by altering the physiological function of neuronal cells. In this study, we identified Brain Reactive Autoantibodies (BRAAs) against murine neuronal membrane proteins (M.W. 27.5 and 29.5 kD) and found them correlating with psychosis and/or seizures in lupus patients. They were specific to neuronal membrane tissues of mammalian origin and are significantly associated with psychosis and/or seizures (p<0.0001). These membrane proteins mass spectrometry profiles did not match to any published protein sequences. These BRAAs may play important roles in the pathophysiology of neuropsychiatric lupus.
Adult↗
PCR-RFLP genotyping for exon 1 and promoter region mutations of the human mannose binding lectin (MBL-2) gene.
The Mannose Binding Lectin (MBL) plays an important role in innate immunity and its genetic deficiencies are associated with frequent and prolonged infections. Serum MBL determination may not accurately detect acute phase protein levels and it is also difficult to detect dysfunctional protein. Genotyping of the exon 1 and promoter regions in the MBL gene will provide useful information on the presence of deficiencies in patients. A reproducible PCR-RFLP method is described to accurately detect genotypes of exon 1 and polymorphic haplotypes of the promoter region in the MBL gene.
Base Sequence↗
Development of an integrated membrane process for water reclamation.
An integrated membrane process (IMP) comprising a membrane bioreactor (MBR) and a reverse osmosis (RO) process was developed for water reclamation. Wastewater was treated by an MBR operated at a sludge retention time (SRT) of 20 days and a hydraulic retention time (HRT) of 5.5 h. The IMP had an overall recovery efficiency of 80%. A unique feature of the IMP was the recycling of a fraction of RO concentrate back to the MBR. Experimental results revealed that a portion of the slow- and hard-to-degrade organic constituents in the recycle stream could be degraded by an acclimated biomass leading to an improved MBR treatment efficiency. Although recycling concentrated constituents could impose an inhibitory effect on the biomass and suppress their respiratory activities, results obtained suggested that operating MBR (in the novel IMP) at an F/M ratio below 0.03 g TOC/g VSS.day could yield an effluent quality comparable to that achievable without concentrate recycling. It is noted in this study that the novel IMP could achieve an average overall TOC removal efficiency of 88.940% and it consistently produced product water usable for high value reuse applications.
Biomass↗
Biofilm morphology and nitrification activities: recovery of nitrifying biofilm particles covered with heterotrophic outgrowth.
Biofilm processes are commonly used for nitrification. Operationally, a whitish heterotrophic biofilm layer tends to develop onto nitrifying biofilm when it has been exposed to organic carbon-containing wastewater for a prolonged period. The development of a heterotrophic biofilm layer could lead to deterioration in nitrification activities and biofilm morphology. The recovery characteristics, in terms of biofilm morphology and nitrification activities, of deteriorated biofilm particles (i.e. nitrifying biofilm particles covered with heterotrophic outgrowth) were investigated by transferring the deteriorated biofilm particles (from an Ultra-Compact Biofilm Reactor (UCBR) which was part of a packed bed-UCBR system used for treating organic carbon and ammonia-containing wastewater) to a UCBR fed solely with ammonia wastewater (referred to as 'Recovery-UCBR'). At a hydraulic retention time (HRT) of 8.7 h and a sand-carrier concentration of 4.0% (v/v), density of the outer heterotrophic biofilm layer reduced progressively which led to subsequent detachment of this layer from the nitrifying biofilm particles. As a result, morphology of the nitrifying biofilm improved gradually in the Recovery-UCBR. A stable nitrification rate of up to 1.74 kg NH4+-N/m3 d was obtained in the Recovery-UCBR.
Ammonia↗
Two-stage SBR for treatment of oil refinery wastewater.
A two-stage sequencing batch reactor (SBR) system was used for treatment of oily wastewater with COD and oil and grease (O&G) concentrations ranging from 1,722-7,826 mg/L and 5,365-13,350 mg/L, respectively. A suitable start-up protocol was developed using gradual increase in oily wastewater composition with methanol as the co-substrate. This strategy enabled a short acclimation period of 12 days for the sludge in the two-stage SBR to adapt to the oily wastewater. After acclimation, the 1st stage and 2nd stage SBRs were able to achieve COD removals of 47.0+/-2.4% and 95.3+/-0.5%, respectively. The 1st stage SBR was able to achieve 99.8+/-0.1% of O&G removal and effluent O&G from the 1st stage SBR was only 6+/-2 mg/L. The 2nd stage SBR was used to further remove COD in the effluent from the 1st stage SBR. The final effluent from the 2nd stage SBR had a COD concentration of 97+/-16 mg/L with no detectable O&G content. Thus, a two-stage SBR system was shown to be feasible for treating high strength oily wastewater to meet the local discharge standards.
Bioreactors↗
Removal of MS2 bacteriophage using membrane technologies.
Removals of MS2 bacteriophage virus using different membrane materials under different operating pressures were investigated. The results obtained in this study suggested that a better log removal in terms of MS2 bacteriophage virus could be achieved using Polyamide RO membrane under the optimum operating pressure of 100 psi. It is further noted that variable MS2 influent concentration levels resulted in corresponding variable log removals of the bacteriophages by the Polyamide RO membrane. The presence of MS2 bacteriophage virus in the effluent could possibly be due to leakage of bacteriophages through the membranes structure. Investigations using SEM and AFM showed that there were gaps or pores present in the membrane structure which were sufficiently large for the MS2 viruses to pass through.
Bacteria, Anaerobic↗
Influence of age on the presentation and outcome of acidotic and hyperosmolar diabetic emergencies.
BACKGROUND: Diabetic emergencies associated with ketoacidosis (DKA) and a hyperosmolar, hyperglycaemic state (HHS) are both acute life-threatening metabolic disturbances. Traditionally, DKA and HHS have been classified as distinct entities but there is evidence to suggest that patients can present with elements of both conditions. AIMS: To examine the presentation profiles, mortality rates and prognostic factors associated with a fatal outcome for diabetic patients admitted with ketoacidosis and/or hyperosmolarity. METHODS: A retrospective analysis of 312 admissions to an Australian tertiary referral hospital between 1986 and 1999. RESULTS: Of the patients surveyed, DKA was the diagnosis for 171 presentations (55%), HHS was the diagnosis for 47 presentations (15%) and combined DKA and HHS (DKA-HHS) was diagnosed for 94 presentations (30%). Age at presentation for DKA patients (33+/-1.2 years) was significantly less (P< 0.01) than DKA-HHS patients (44+/-2.4 years). This, in turn, was significantly less (P < 0.01) than HHS patients (69+/-1.7 years). There were 15 deaths for the 312 presentations, resulting in an overall mortality rate of 4.8%. Combined mortality rates according to age at presentation were: (i) 0/134 for patients aged <35 years, (ii) 1/85 (1.2%) for patients aged 35-55 years and (iii) 14/93 (15.0%) for patients aged >55 years. For the three categories of diabetic emergencies, mortality rates were: (i) 2/171 (1.2%) for DKA, (ii) 5/94 (5.3%) for DKA-HHS and (iii) 8/47 (17%) for HHS. For all presentations associated with ketoacidosis - regardless of the degree of hyperosmolarity - the mortality rate was 7/264 (2.7%), however for all presentations with hyperosmolarity regardless of the degree of acidosis - the mortality rate was 13/141 (9.2%). When the associations between age, category of diabetic emergency, serum osmolarity and various other biochemical parameters with mortality were assessed by logistic regression analysis, age and the degree of hyperosmolarity were found to be the most powerful predictors of a fatal outcome. In particular, patients aged >65 years presenting with a serum osmolarity >375 mOsmol/L were at greatest risk. However, in a multivariate analysis only age emerged as a significant independent predictor of mortality (P < 0.01). CONCLUSIONS: The mixed state of ketoacidosis and hyperosmolarity was observed in 30% of presentations for diabetic hyperglycaemic emergencies. Although age and degree of hyperosmolarity both influenced mortality rates, only age was found to be an independent predictor of mortality. The mortality rate for diabetic emergencies associated with ketoacidosis remained low, in keeping with other studies. By contrast, the mortality rate for diabetic emergencies associated with a hyperosmolar state remained considerably higher. This higher mortality will most likely persist because deaths associated with a hyperosmolar state were in elderly patients with significant comorbidity.
Adolescent↗
Packed bed columns for high rate nitrogen and carbon removals.
Two packed bed column (PB) systems, namely anoxic-anoxic and anoxic-oxic were investigated for treatment of wastewater containing high concentrations of nitrogen (N) and COD. The anoxic-anoxic PB removal rates 6.70 kg N/m3 x d and 26.02 kg COD/m3 x d, respectively. The responding removal rates of the anoxic-oxic PB system were 7.41 kg N/m3 and 28.00 kg COD/m3 x d, respectively. The N and COD removal efficiencies of anoxic anoxic PB system were in the range of 99.2-100% and 97.2-98.8%, respectively. The corresponding removal efficiencies of anoxic-oxic PB system were 97.5-100% and 98.6-99.4%, respectively. These findings showed that a PB system consisting of anoxic-oxic columns in series has a high capacity to remove nitrogenous and carbonaceous compounds even though the influent to the anoxic stage was oxygenated. Better system stability in terms of denitrification was, however, obtained with the anoxic-anoxic system.
Bioreactors↗
Toxicity assays to determine the start-up strategy for an anaerobic sequencing batch reactor (anSBR).
Addition of glucose as the co-substrate and the use of a water-based polymer to enhance granulation were studied with the aim of shortening the start-up period of an anSBR (anerobic sequencing batch reactor) for high-strength industrial wastewater treatment. An initial start-up feed composition consisting of 70% sucrose and 30% industrial wastewater was favorable to reduce the start-up time. Increase in the average particle size and reduction in settled supernatant turbidity was observed with increased water-based polymer addition up to a concentration of 0.1 m/L. Polymer dosages above 0.1 ml/L were undesirable as big and "flaky" flocs were formed which prevented the flocs from settling quickly. Addition of 0.005 ml/L to 0.1 ml/L polymer to the mixed liquor had no observable adverse effects on the anaerobic biomass metabolism. Instead, the addition of the polymer appeared to improve biogas production and had an overall positive effect on anSBR performance treating the industrial wastewater.
Bacteria, Anaerobic↗
Hypersensitivity of pulmonary C fibre afferents induced by cationic proteins in the rat.
1. Airway administration of synthetic cationic proteins, poly-L-lysine (PLL) and poly-L-arginine (PLA), is known to induce bronchial hyper-responsiveness, and an involvement of bronchopulmonary C fibre activation has been suggested. In this study we investigated the effects of PLL and PLA on single-unit pulmonary vagal C fibre afferents in anaesthetized, open-chest rats. 2. Intratracheal (I.T.) instillation of PLL or PLA activated C fibre endings in a dose-dependent manner; for example, a high dose of PLL (50 microg in 0.1 ml) had a sporadic but intense stimulatory effect on these afferents. The augmented C fibre activity slowly declined but remained elevated even after 120 min. 3. Intratracheal instillation of PLL or PLA greatly enhanced the sensitivities of pulmonary C fibres to both lung inflation and chemical stimuli (e.g. capsaicin); for example, the change in fibre activity in response to constant-pressure lung inflation (tracheal pressure (P(t)) = 30 cmH(2)O; 10 s duration) increased by approximately 6-fold after PLL instillation. 4. When administered by intravenous injection or instilled into a different region of the lung, PLL or PLA, even at a higher dose, failed to have any effect on the C fibre endings. 5. The stimulatory and sensitizing effects of PLL or PLA were completely nullified when their cationic charges were neutralized with low molecule weight heparin. 6. In conclusion, I.T. instillation of synthetic cationic proteins causes an intense stimulatory effect on pulmonary C fibres and potentiates their sensitivities to both lung inflation and chemical stimuli. These effects are probably generated by an interaction between the cationic charges carried by these proteins and the airway mucosa.
Animals↗
Retrospective analysis of mortalities associated with medication errors.
The types, causes, contributing factors, and patient demographics of fatal medication errors were reviewed. Case reports of medication errors from hospitals, ambulatory care settings, and patients' homes that were entered in FDA's Adverse Event Reporting System during 1993-98 were the source of information on fatal medication errors. Each report was classified using predefined criteria and a taxonomy developed by the National Coordinating Council for Medication Error Reporting and Prevention. The types, causes, contributing factors, and patient demographics were identified, and the causality of each case was assessed to prevent future fatalities. The data indicated 5,366 medication error reports. Fifty-nine reports were excluded and classified as duplicate reports or intentional overdoses. Of the remaining medication error reports, 68.2% resulted in serious patient outcomes and 9.8% were fatal. Of the 469 fatal medication error reports, 48.6% occurred in patients over 60 years. The most common types of errors resulting in patient death involved administering an improper dose (40.9%), administering the wrong drug (16%), and using the wrong route of administration (9.5%). The most common causes of errors were performance and knowledge deficits (44%) and communication errors (15.8%). Fatal medication errors accounted for approximately 10% of medication errors reported to FDA and were most frequently the result of improper dosing of the intended drug and administration of an incorrect drug. A review of case reports of medication errors from 1993 to 1998 yielded information on the most frequent causes of and contributing factors involved in fatal medication errors.
Adolescent↗
Digital imaging considerations for gel electrophoresis analysis systems.
Gel analysis system purchasers have a large variety of digital imaging products to choose from today. Understanding the specifications presented by the manufacturers is important to ensure that the system fits the needs ofthe researcher using the system. The background information contained in this paper explains the terminology and many of the specifications along with their significance.
Computers↗
Percutaneous endocardial transfer and expression of genes to the myocardium utilizing fluoroscopic guidance.
Experimental studies indicate that administration of angiogenic proteins or genes by the epicardial or intracoronary route can stimulate development of new collateral vessels and improve myocardial perfusion. An endocardial catheter-based approach to this therapy would obviate the need for surgery, while preserving the effectiveness of direct intramyocardial administration. Fluoroscopic guidance and prototype, preformed, coaxial catheters were used to examine the feasibility of percutaneous catheter-based adenovirus (Ad)-mediated gene transfer and expression in normal swine myocardium. The feasibility of intramyocardial administration (100 microl/injection) of a radiocontrast agent and black tissue dye to all regions of the left ventricle (septum, anterior, lateral, and inferior wall) was confirmed fluoroscopically and on postmortem examination. Injections of replication-deficient adenovirus (10 injections of 10(11) particle units/100 microl each) coding for beta-galactosidase (Adbetagal) or vascular endothelial growth factor (Ad(GV)VEGF121.10) were administered to the left ventricular free wall to examine endocardial based gene transfer and expression. beta-Galactosidase activity was detected by histochemical staining and quantitative assay in targeted regions of the myocardium. Regional VEGF expression was found to be significantly greater in targeted regions (1.3 +/- 0.4 ng/mg protein) as compared with non-targeted regions (0.3 +/- 0.1 ng/mg protein) or regions injected with control (Adbetagal) virus (0.2 +/- 0.03 ng/mg protein, P < 0.001). Catheter-based Ad mediated endocardial gene transfer and expression is feasible using percutaneous, fluoroscopically guided, preformed, coaxial catheters. This approach should be clinically useful to administer angiogenic genes to the ischemic myocardium.
Adenoviridae↗
Transmyocardial laser revascularization dose response: enhanced perfusion in a porcine ischemia model as a function of channel density.
BACKGROUND: Transmyocardial laser revascularization (TMR) appears to provide symptomatic relief to patients with ischemic heart disease, but evidence that TMR enhances perfusion to ischemic myocardium remains limited. Furthermore, it is uncertain whether there exists a TMR dose-response relationship that is a function of channel number. We therefore compared restoration of blood flow as analyzed by rest and stress 99mTc-sestamibi scans and histologic grading of neovascularization after 50-channel, 25-channel, or 10-channel TMR using the excimer laser in an established model of porcine myocardial ischemia. METHODS: Yorkshire swine underwent a thoracotomy and placement of an ameroid constrictor around the proximal circumflex coronary artery. Three weeks later, the animals underwent resting and adenosine stress 99mTc-sestamibi scans for evaluation of ischemia immediately before repeat thoracotomy and TMR with either 50 channels (n = 4), 25 channels (n = 4), or 10 channels (n = 4) in the circumflex territory. The animals underwent repeat perfusion analyses 4 weeks later, after which the animals were sacrificed and the hearts were perfusion fixed for histologic evaluation of neovascularization. RESULTS: All animals survived to sacrifice. Semiquantitative analyses of the sestamibi perfusion scans 4 weeks after lasing demonstrated significant improvement (p < 0.04) in stress-induced ischemia in the 50-channel TMR animals, but not in the 25- or 10-channel TMR groups, as compared with scans obtained immediately before lasing. A computerized image analysis of perfusion scans similarly demonstrated an improvement in the area of ischemia of 42% +/- 22% in the scans obtained 4 weeks after lasing compared with scans obtained immediately before lasing in the 50-channel group (p < 0.004), but only a 12% +/- 9% improvement in the 25-channel group and an 8% +/- 4% improvement in the 10-channel group (p > 0.05). Histologic assessment of neovascularization demonstrated significantly greater number of microvessels per low-power field in the 50- versus the 25- and 10-channel groups (p < 0.001). CONCLUSIONS: In an animal model of myocardial ischemia, TMR appears to enhance myocardial perfusion. A dose-response relationship related to channel number may be of significance when evaluating the efficacy of various treatment strategies.
Adenosine↗
Afferent properties and reflex functions of bronchopulmonary C-fibers.
Bronchopulmonary C-fiber afferents are characterized by their distinct sensitivity to chemical stimuli in the airways or pulmonary circulation. Responses evoked by activating these afferents are mediated by both central reflex pathways and by local or axon reflexes involving the release of tachykinins from sensory endings. Bronchopulmonary C-fiber stimulation reflexly reduces tidal volume and increases respiratory rate, constricts the airways, increases mucus secretion in the airways, and is associated with coughing. Cardiovascular effects include bradycardia, a fall in cardiac output, and bronchial vasodilation that increases airway blood flow despite systemic hypotension. In animals, C-fiber stimulation inhibits skeletal muscle activity, and in humans, is accompanied by burning and choking sensations in the throat and upper chest. Recent studies have identified additional physiologic and pharmacologic stimuli to these afferents, such as hydrogen ions, adenosine, reactive oxygen species, and hyperosmotic solutions. Furthermore, increasing evidence indicates that the excitability of these afferents is enhanced by the local release of certain autocoids (e.g. PGE2) during airway inflammation. These findings further indicate that vagal C-fiber endings in the lungs and airways play an important role in regulating the cardiopulmonary functions under both normal and abnormal physiologic conditions.
Animals↗
Sensitivity of vagal afferent endings to chemical irritants in the rat lung.
This study was carried out to investigate the relationship between the conduction velocity of the vagal afferents arising from the rat lungs and their sensitivities to capsaicin, other chemical irritants, and lung inflation. We recorded single-unit activities of vagal pulmonary afferents (n = 205) in anesthetized, open-chest rats, and distinguished C fibers (conduction velocity < 2 m/sec) from myelinated afferents; the latter group was further classified into rapidly adapting pulmonary receptors (RARs) and slowly adapting pulmonary stretch receptors (SARs) on the basis of their adaptation indexes to lung inflation. Right-atrial injection of capsaicin (1 microg/kg) evoked an abrupt and intense stimulatory effect in 88.9% (64/72) of the pulmonary C fibers tested, but only a mild stimulation in 6.3% (3/48) of the RARs and none of the SARs. Other inhaled and injected chemical stimulants (e.g., cigarette smoke, lactic acid) activated 68.9% (42/61) of the pulmonary C fibers. The same chemical irritants exerted a mild stimulatory effect in only 14.5% (8/55) of the RARs; this subgroup of RARs exhibited a low or no baseline activity, and half of them were located near the hilum. Chemical stimulants had little or no effect on SARs. The response of pulmonary C fibers to lung inflation (tracheal pressure = 30 cm H2O) was not only extremely weak, but also showed a longer onset latency and an irregular pattern. In a sharp contrast, lung inflation evoked rapid and vigorous discharges in both RARs and SARs. In conclusion, C fibers are the primary type of chemosensitive vagal pulmonary afferents in rat lungs.
Animals↗
Exploring factors influencing Chinese women's decision to have elective caesarean surgery.
OBJECTIVES: to identify the factors that influence Hong Kong Chinese women's decision to have an elective caesarean section. To explore Chinese women's perceptions of their autonomous involvement in childbirth decision-making. DESIGN: a qualitative exploratory design. SETTING: a postnatal ward of a private hospital in Hong Kong. PARTICIPANTS: a purposive sample of six postnatal women who had undergone an elective caesarean section. FINDINGS: four thematic categories were identified including: avoiding fetal and maternal risks, exercising autonomy to make an independent choice, Chinese belief systems, and rejoicing and regretting. KEY CONCLUSIONS AND IMPLICATIONS FOR PRACTICE: we propose the provision of a 'named' midwife and continuity of care. Improving the availability of information on caesarean sections, accommodating a Chinese belief system in the planning of midwifery services at the international level and establishing post caesarean section peer support groups are recommended.
Adult↗