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Biomedical subjects

M Wong

Publications and source records attributed to M Wong.

At least 343 records · Page 19Linked to original sources
PubMed1982

Functional heterogeneity of culture-grown bone marrow-derived macrophages. II. Lymphokine stimulation of antigen-presenting function.

The activation of immunostimulatory activity and Ia expression was studied in pure populations of murine macrophages (M phi) grown in vitro from bone marrow precursor cells in the presence of L cell-conditioned medium as the source of colony-stimulating factor. During exponential growth, the M phi developed maximal Ia-dependent antigen-presenting activity as detected by the induction of antigen-specific T cell proliferation, but the proportion of Ia+ M phi was low (less than 10%). Fractionation of the M phi according to size by velocity sedimentation resulted in concentration of the antigen-presenting cells in the smallest fraction, but the enrichment of Ia+ M phi in this fraction was less than twofold. All fractions also showed comparable degrees of antigen uptake regardless of their T cell-stimulating activity. Thus Ia and antigen, although obviously essential, are insufficient for full manifestation of antigen-presenting function. Activation of M phi with lymphokines from Mycobacterium-activated lymph node cells resulted in enhanced Ia expression in all fractions, but only small M phi showed an enhancement in antigen presentation. Large activation M phi were found to exert an immunosuppressive effect that probably neutralized any augmentation of stimulatory activity. thus heterogeneity can be demonstrated in i) the function of unstimulated M phi, ii) the responsiveness of subsets to stimulation, and iii) the manifestation of activated functions.

Animals↗
PubMed1981

Comparative evaluation of segmental asynergy in remote myocardial infarction by radionuclide angiography, two-dimensional echocardiography, and contrast ventriculography.

Radionuclide angiography (RNA), two-dimensional echocardiography (2DE), and contrast ventriculography (CVG) were compared in the evaluation of regional wall motion (RWM) in 58 patients with remote myocardial infarction (MI). All 58 patients were studied by 2DE, 52 by RNA, and 24 by CVG. Severe degrees of segmental asynergy (akinesia/dyskinesia) were noted more often by 2DE (56% of all segments, p less than 0.005) and CVG (52%, p less than 0.05) than by RNA (39%). The apex more the most frequent site of akinesia/dyskinesia by all technique (43% by RNA, 36% by 2DE, and 45% by CVG). 2DE and RNA agreed in 64% of regions (p less than 0.005), 2DE and CVG agreed in 68% (p less than 0.005), and RNA and CVG agreed in 70% (p less than 0.005); the highest agreement was for the apical region. Dyskinesia was noted in 77% of patients by RNA, in 71% by 2DE, and 79% by CVG. RNA and CVG agreed in 89% of patients and in 57% of regions, 2DE and CVG agreed in 67% of patients and in 53% of regions, and RNA and 2DE agreed in 71% of patients and in 38% of regions. Combined RNA and 2DE detected dyskinesia in 94% of the 16 patients with dyskinesia by CVG who underwent all three techniques and in 90% of the 52 patients studied by RNA and 2DE. We conclude that (1) RNA, 2DE an CVG agree significantly in the evaluation of regional wall motion; (2) there is better agreement concerning the presence or absence of dyskinesia in a given patients than the exact region involved; and (3) the combination of RNA and 2DE is more useful than either alone as a screening procedure for the detection of ventricular dyskinesia.

Adult↗
PubMed1981

Reproducibility of left ventricular internal dimensions with M mode echocardiography: effects of heart size, body position and transducer angulation.

Analysis was made of the variables of heart size, body position and transducer angle affecting the reproducibility of left ventricular internal dimensions as measured with M mode echocardiography. Echocardiograms were recorded in 24 subjects as the thorax was incrementally rotated and tilted. Transducer angle was noted from a three plane level attached to the probe. Constants were the technician, transducer placement and the interpreter. Heart rates varied insignificantly; respirations were held. Groups A and B were defined by their initial left ventricular internal dimensions at end-diastole (LVIDd): 49 +/- 5.9 and 73 +/- 8.6 mm (group mean +/- standard deviation). With body position constant the measurement error between duplicate recordings of LVIDd was +/- 1.2 mm (coefficient of variation = 1.8 percent) in Group A and +/- 4.5 mm (coefficient of variation = 4.6 percent) in Group B (p less than 0.001). Transducer angle varied 12 degrees between duplicate recordings in both groups. As the position of the thorax changed, the transducer followed, maintaining approximately the same incline with the chest wall. In both groups errors for combined LVIDd recorded with rotation and tilt, respectively, were unchanged from the duplication error. Thus, when the spatial orientation between the transducer and heart is held constant, it is the size of the heart that determines the reproducibility of the measurement of left ventricular internal dimensions.

Cardiac Volume↗
PubMed1981

Intravenous dipyridamole combined with isometric handgrip for near maximal acute increase in coronary flow in patients with coronary artery disease.

Twenty-four patients with coronary artery disease were studied during cardiac catheterization to determine the effects of sustained isometric handgrip exercise and intravenous dipyridamole and their combination on coronary and systemic hemodynamics and measured coronary luminal caliber. During 4 to 5 minutes of 25 percent maximal handgrip, blood pressure and heart rate increased 24 and 19 percent, respectively, coronary sinus flow increased to 1.7 x baseline value, and epicardial coronary arteries constricted to increase predicted flow resistance by 40 percent in 36 diseased arterial segments. After a 4 minute intravenous infusion of dipyridamole (0.56 mg/kg body weight), systemic pressure decreased 8 percent, heart rate increased 23 percent, coronary sinus flow increased to 2.4 x baseline value and coronary luminal caliber was unchanged. During isometric handgrip initiated 6 minutes after the infusion of dipyridamole, systemic pressure and heart rate increased to 14 and 31 percent, respectively, above control values, coronary sinus flow increased to 3.3 x baseline value (3.8 x baseline value in patients with normal anterior perfusion) and stenotic flow resistance increased by 36 percent. The response of coronary flow to the combined stresses was 68 percent greater than the response to dipyridamole alone (p less than 0.02); these flow levels exceed values previously reported for the human coronary circulation. Aminophylline plus nitroglycerin appears to assure patient safety.

Acute Disease↗
PubMed1981

Abnormal mitral valve coaptation in hypertrophic obstructive cardiomyopathy: proposed role in systolic anterior motion of mitral valve.

Two dimensional echocardiographic evaluation utilizing the apical four chamber and apical long axis views was made in 10 normal subjects and 35 patients with hypertrophic cardiomyopathy, including 16 without and 19 with systolic anterior motion of the mitral valve. Mitral valve leaflets were imaged throughout the cardiac cycle. The normal subjects and the patients with hypertrophic cardiomyopathy without systolic anterior motion demonstrated mitral valve coaptation that seemed to involve the distal tip of the anterior leaflet. In contrast, patients with hypertrophic cardiomyopathy with systolic anterior motion demonstrated abnormal coaptation, so that the posterior leaflet coapted with a mid portion of the anterior leaflet, leaving a distal "residual" anterior leaflet in the left ventricle during systole. A sharp angulation of this distal leaflet in mid systole toward the interventricular septum is thought to represent systolic anterior motion. It is speculated that abnormal mitral leaflet coaptation in necessary for development of leaflet systolic anterior motion, which is correlated with dynamic left ventricular outflow gradients in hypertrophic obstructive cardiomyopathy.

Adult↗
PubMed1981

Ring chromosome 14: a distinct clinical entity.

An infant girl with ring chromosome 14 is presented. The findings in this patient and in six previously reported cases of a ring 14 suggest that a characteristic clinical syndrome is associated with this chromosome aberration. The major features of the ring chromosome 14 syndrome include mental retardation, a disorder of skin pigmentation, seizures, and dysmorphic features, including flat occiput, epicanthal folds, downward slanting eyes, flat nasal bridge, upturned nostrils, short neck, and large low set ears.

Abnormalities, Multiple↗
PubMed1981

Reverse redistribution: worsening of thallium-201 myocardial images from exercise to redistribution.

Reverse redistribution (RR) i.e., worsening of images from exercise to redistribution, was noted in 21 (7%) of 300 consecutive thallium-201 (201TI) exercise and redistribution myocardial imaging studies. In 13, there were reversible defects consistent with ischemia in addition to redistribution defects. Twenty RR defects were noted in 15 patients who underwent cardiac catheterization; 9 had triple, 4 had double and 2 had single vessel coronary artery disease. Seventeen (85%) of the RR defects were in the distribution of severely diseased vessels; 8 with 100% occlusion and 9 with 90-99% stenosis. The remainder were associated with 50-60% stenoses. Ten RR areas (50%) were supplied by collateral vessels and 3 (15%) by bypass grafts. Fourteen of the 18 (78%) areas studied with left ventriculography were associated with abnormally contracting segments. These results suggest that RR is a marker for significant coronary artery disease.

Cardiac Catheterization↗
PubMed1981

Size and motion of the mitral valve annulus in man. I. A two-dimensional echocardiographic method and findings in normal subjects.

Using wide-angle, phased-array, two-dimensional echocardiography, mitral leaflets and their annular attachments were recorded from a view close to the standard apical four-chamber view. The transducer was rotated and recordings were made at 30 degrees rotational intervals around the circumference of the mitral valve annulus. To reconstruct the annulus, the diameters (chords) from each rotational interval were arranged around a reference point. This was done for 12 times during the cardiac cycle. Annular areas were planimetered and circumferences measured. Correlation was good for areas reconstructed and measured by the same observer on separate occasions (r = 0.963) and by two different observers (r = 0.987). In 11 normal subjects the annular area index (area divided by body surface area) increased during diastole to a maximum of 3.8 +/- 0.7 cm2/m2 (mean +/- SD) in late diastole. There was presystolic followed by systolic narrowing to a minimum in midsystole. The mean reduction in area was 26 +/- 3%. The maximal annular circumference was 9.3 +/- 0.9 cm and the mean reduction in circumference was 13 +/- 3%. The overall motion pattern was similar to that reported in experimental studies in the dog. Mitral annular reconstruction may provide new information about normal and abnormal function of the mitral valve apparatus.

Diastole↗
PubMed1981

Characterization of macrophage subpopulations responsive to activation by endotoxin and lymphokines.

The subpopulations of murine macrophages (M phi) that can be activated by endotoxin (LPS) and lymphokines to produce lymphocyte-activating factor, or interleukin 1 (IL-1), and to express cytostatic and cytolytic activities against tumor cells were characterized in 3 cell populations with immature and mature M phi in various proportions, namely, normal peritoneal cells, glycogen-induced peritoneal cells, and cultured bone marrow M phi. There is disagreement in the literature as to whether tumor cytotoxicity can be elicited from all M phi or from a subset of small, newly formed peroxidase-positive (p+) monocytes. Using the technique of cell size fractionation, which separates p+ and p- M phi to various extents, we have found that the magnitude of te response to LPS and lymphokines increases with cell size (and hence maturity or the degree of prior stimulation) and is not exclusive to p+ M phi. Our results are consistent with the concept that all M phi, irrespective of developmental stage, can exist in a continuum of activated states, depending on the nature of the activation signals.

Animals↗
PubMed1980

Characterization of poly(ADP-ribose)--histone H1 complex formation in purified polynucleosomes and chromatin.

Poly(ADP-ribose) [poly(ADP-Rib)] polymerase of HeLa nucleosomes has been shown in vitro, to catalyze the synthesis of a complex of histone H1 containing 2 H1 histones and 15-16 units of oligo(ADP-Rib). The synthesis of the H1 complex in vitro was compared in polynucleosome populations of various sizes (3--16 and greater than 30) released from HeLa nuclei following micrococcal nuclease digestion. Poly(ADP-Rib) was synthesized from [32P]NAD and the poly(ADP-ribosyl)ation of H1 was studied by selective H1 extraction, gel electrophoresis and autoradiography. Quantitative differences in H1 complex formation occurred when either chromatin concentration or polynucleosome length was varied. The data indicated that H1 complex formation in vitro was favored in polynucleosomes 16 nucleosomes long as compared to 8 nucleosomes. A series of partially ADP-ribosylated H1 species was also detected. Partially modified H1 species migrate more slowly than pure H1 in dodecylsulfate gels. The reduced mobility is a function of the number of attached ADP-Rib moieties. Thus, molecules containing one molecule of H1 and various numbers of ADP-Rib residues can be separated. When the partially modified H1 species were incubated in alkali to cleave the linkage of ADP-Rib to protein, (ADP-Rib1-15) were detected by chain length analysis on 15% polyacrylamide gels. The intermediate H1 species could be chased, in vitro, into as H1 complex with NAD and thus were determined to be successive precursors in the formation of the H1 complex. Evidence is presented that the H1 complex is synthesized in intact cells permeabilized with lysolecithin.

Chromatin↗
PubMed1980

Antigenic relationships and rapid identification of Peptostreptococcus species.

Antisera against whole cells of each Peptostreptococcus species (P. anaerobius, P. micros, P. parvulus, and P. productus) were produced in rabbits. When these antisera were reacted against sonically disrupted cells and culture supernatant fluids in Ouchterlony tests, lines of identity were obtained among the antigens from all the species and uninoculated culture medium. When the antisera were subsequently absorbed with the dehydrated culture medium used to grow the peptostreptococci, all cross-reactions in heterologous antigen-antibody combinations were eliminated, leaving only species-specific precipitin arcs. These absorbed antisera, specific for each Peptostreptococcus species by Ouchterlony tests, were used for rapid identification studies. Staphylococcus aureus-bearing protein A was sensitized with each absorbed antiserum. These reagents produced specific coagglutination reactions with suspensions of each Peptostreptococcus reference strain and with 16 clinical isolates. No cross-reactions occurred with the Streptococcus intermedius, Peptococcus magnus, or Peptococcus asaccharolyticus strains tested.

Agglutination Tests↗