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Biomedical subjects

Y H Kong

Publications and source records attributed to Y H Kong.

10 recordsLinked to original sources
PubMed2006

Floc-forming properties of polyphosphate accumulating organisms in activated sludge.

The physico-chemical characteristics of polyphosphate-accumulating organisms (PAO) involved in enhanced biological phosphorus removal (EBPR) was investigated in order to find a novel method for phosphorus recovery. If the physico-chemical characteristics of PAO are different from those of other main floc components, it may be possible to enrich PAO in bulk water or in the floc material for improved recovery of phosphorus. A combination of shear tests, chemical manipulation, and quantification of PAO by fluorescence in situ hybridization was applied. The microcolony strength of both Rhodocyclus-related PAO and Actinobacteria-related PAO was generally high as no treatment could break up more than 20% of all PAO in microcolonies. In contrast, it was possible to remove 20-40% of the organic matter and other bacterial cells by applying a high pH value or adding EDTA. With that a selective enrichment of PAO in the remaining floc material was possible. The feasibility of applying this selective PAO enrichment in flocs remains to be evaluated in full-scale plants for P-recovery.

Actinobacteria↗
PubMed2002

Role of "G-bacteria" in anaerobic substrate uptake in a SBR with no phosphorus removal.

Biomass from an SBR running with no enhanced biological phosphorus removal (EBPR) but which exhibited anaerobic assimilation of glucose and acetate, was dominated by "G-bacteria", cocci in tetrads and clusters. Extracted 16S rDNA was amplified by PCR and then analysed using Denaturing Gradient Gel Electrophoresis (DGGE). Major bands were extracted and their sequences determined. Clone libraries were also prepared, the 16S rDNA extracted, PCR performed and the resultant fragments run by DGGE to aid in identifying the DGGE bands and provide fuller sequences than available by DGGE alone. The two approaches together allowed several bands to be identified. Probes for FISH analyses were designed for some of these in attempts to see to which phylogenetic group "G-bacteria" belonged, and whether they represented the dominant bands detected by DGGE. Then FISH/Microautoradiography (MAR) was used in attempts to see which bacteria there were assimilating substrates anaerobically. Results indicated that the "G-bacteria" were phylogenetically diverse, but mainly alpha-proteobacteria and members of the high G+C% gram-positive bacteria. Not all of these could assimilate glucose and/or acetate anaerobically, and Amaricoccus, the original "G-bacteria" of Cech and Hartman, was not detected.

Bacteria, Anaerobic↗
PubMed2001

Structure and functional analysis of the microbial community in an aerobic: anaerobic sequencing batch reactor (SBR) with no phosphorus removal.

The bacterial community of an aerobic:anaerobic non-P removing SBR biomass fed a mixture of acetate and glucose was analysed using several 16S rRNA based methods. Populations responsible for anaerobic glucose and acetate assimilation were determined with fluorescent in situ hybridization (FISH) in combination with microautoradiography (FISH/MAR). At 'steady state' this community consisted of alpha-Proteobacteria (26%) and gamma-Proteobacteria (14%), mainly appearing as large cocci in tetrads (i.e. typical 'G-Bacteria'). Large numbers of low G+C bacteria (22%), and high G+C Gram-positive bacteria (29%) seen as small cocci in clusters or in sheets were also detected after FISH. DGGE fingerprinting of PCR amplified 16S rDNA fragments and subsequent cloning and sequencing of several of the major bands led to the identification of some of these populations. They included an organism 98% similar in its 16S rRNA sequence to Micropruina glycogenica, and ca. 76% of the high G+C bacteria responded to a probe MIC 184, designed against it. The rest responded to the KSB 531 probe designed against a high G+C clone sequence, sbr-gs28 reported in other similar systems. FISH analyses showed that both these high G+C populations were almost totally dominated by small clustered cocci. Only ca. 2% of cells were beta-Proteobacteria. None of the alpha- and gamma-Proteobacterial 'G-bacteria' responded to FISH probes designed for the 'G-Bacteria' Amaricoccus spp. or Defluvicoccus vanus. FISH/MAR revealed that not all the alpha-Proteobacterial 'G-Bacteria' could take up acetate or glucose anaerobically. Almost all of the gamma-Proteobacterial 'G-Bacteria' assimilated acetate anaerobically but not glucose, the low G+C clustered cocci only took up glucose, whereas the high G+C bacteria including M. glycogenica and the sbr-gs28 clone assimilated both acetate and glucose. All bacteria other than the low G+C small cocci and a few of the alpha-Proteobacteria accumulated PHB. The low G+C bacteria showing anaerobic glucose assimilation ability were considered responsible for the lactic acid produced anaerobically by this SBR biomass, and M. glycogenica for its high glycogen content.

Acetates↗
PubMed1991

Intracoronary ultrasound evaluation of interventional technologies.

The feasibility and applicability of intravascular ultrasound (IVUS) of the coronary arteries were evaluated in 65 patients undergoing 70 coronary interventional procedures. Morphologic and quantitative analyses were performed with a mechanically rotated IVUS catheter (4.8Fr, 20 MHz) and with orthogonal view cineangiography. A semiautomated edge-detection algorithm was used for cineangiographic quantification. Coronary interventions included 45 percutaneous transluminal coronary angioplasties, 9 excimer lasers, 11 directional coronary atherectomies, 3 rotational atherectomies and 2 stents. Most lesions consisted of a mixture of plaque composition (hard, n = 30; soft, n = 64). Other unique morphologic data by IVUS were plaque topography (eccentric, n = 34; concentric, n = 36) and vessel dissection (IVUS [n = 29] versus angiography [n = 14], p less than 0.05). Postprocedure minimal lumen diameter and cross-sectional area measured by IVUS were larger and poorly correlated with angiography (r = 0.28, standard error of the estimate = 0.52 mm; r = 0.08, standard error of the estimate = 1.0 cm2, respectively). IVUS is more sensitive than angiography when assessing postintervention lesion characteristics including vessel dissection and plaque morphology. Catheter-based ultrasound appears to be a useful adjunct to contrast angiography when evaluating and comparing the therapeutic impact of conventional percutaneous transluminal coronary angioplasty with new technologies.

Algorithms↗
PubMed1989

Correlates of survival in patients with postinfarction ventricular septal defect.

Prognostic indicators of survival in 42 consecutive patients (21 men and 21 women) with postinfarction ventricular septal defect were reviewed. Infarct location was anterior in 57%, inferior in 33%, and combined in 10%. The hospital mortality among 9 patients not receiving surgical therapy was 100%. Of the 33 surgically treated patients, 19 (58%) survived. Time from diagnosis to operation, ventricular function, and presence or absence of shock were analyzed in a logistic regression model to determine which factors carried independent prognostic value. Shock was independently predictive of operative mortality (p less than 0.01). Of additional variables examined, nonsurvivors were characterized by a shorter time from postinfarction ventricular septal defect to operation, a relatively higher incidence of inferior infarction, moderate right ventricular dysfunction and mild left ventricular dysfunction, and a lower right ventricular systolic pressure. Results of postmortem examination were available for 15 nonsurvivors. Quantitative analysis of percent ventricle infarcted revealed that in patients with inferior infarctions, a mean of 31% of the right ventricle was infarcted compared with 10% in patients with anterior infarction (p = 0.059). Kaplan-Meier survival estimates revealed 1-year survival of 70%, 5-year survival of 55%, and 10-year survival of 20%. Seventy percent of survivors were in New York Heart Association class I or II. These data show that, irrespective of ventricular function or timing of operation, the development of shock is the most important predictor of survival in postinfarction ventricular septal defect. The higher mortality in patients with inferior infarction may be associated with a greater degree of right ventricular infarction and consequent dysfunction. Finally, long-term survival and excellent functional recovery can be achieved in patients undergoing operation.

Aged↗
PubMed1980

Type A behavior, hostility, and coronary atherosclerosis.

Type A behavior pattern was assessed using the structured interview and hostility level was assessed using a subscale of the Minnesota Multiphase Personality Inventory in 424 patients who underwent diagnostic coronary arteriography for suspected coronary heart disease. In contrast to non-Type A patients, a significantly greater proportion of Type A patients had at least one artery with a clinically significant occlusion of 75% or greater. In addition, only 48% of those patients with very low scores (less than or equal to 10) on the Hostility scale exhibited a significant occlusion; in contrast, patients in all groups scoring higher than 10 on the Hostility scale showed a 70% rate of significant disease. The essential difference between low and high scorers on the Hostility scale appears to consist of an unwillingness on the part of the low scorers to endorse items reflective of the attitude that others are bad, selfish, and exploitive. Multivariate analysis showed that both Type A behavior pattern and Hostility score are independently related to presence of atherosclerosis. In this analysis, however, Hostility score emerged as more related to presence of atherosclerosis than Type A behavior pattern. These findings confirm previous observations of increased coronary atherosclerosis among Type A patients. They suggest further that an attitudinal set reflective of hostility toward people in general is over and above that accounted for by Type A behavior pattern. These findings also suggest that interventions to reduce the contribution of behavioral patterns to coronary disease risk might profitably focus especially closely on reduction of anger and hostility.

Coronary Disease↗
PubMedDate not supplied

Psychosocial and physical predictors of anginal pain relief with medical management.

This study was undertaken to identify psychosocial and physical characteristics that independently predict anginal pain relief. The original study group comprised over 570 patients in whom the characteristics were identified at the time of coronary arteriography and who were followed up after 6 months of standard medical therapy. In the subset of 382 of these patients who were assessed as having NYHA Class III or IV angina at the time of angiography, a multivariable analysis of 101 baseline descriptors showed that higher scores on the MMPI hypochondriasis scale, unemployment, and more severe right coronary occlusion were significant independent predictors of failure to achieve two-class improvement at follow-up. These three characteristics also predicted continuing severe angina in a subsequent, independent sample of 91 new patients. These findings could help physicians select appropriate treatment by prospectively identifying patients who are unlikely to respond to standard medical treatment of angina.

Adrenergic beta-Antagonists↗