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Biomedical subjects

E S Wang

Publications and source records attributed to E S Wang.

6 recordsLinked to original sources
PubMed2001

Acute myeloid leukemia with t(5;18)(q35;q21).

A case of acute myelocytic leukemia with a translocation (5;18)(q35;q21) is reported. Cytogenetic abnormalities of the long arm of chromosome 5 have long been known to affect hematopoiesis. Although translocations between 5q and other chromosomes have been associated with malignancy, this is the first reported case of a t(5;18) resulting in acute myeloid leukemia. Possible molecular mechanisms underlying the pathogenesis of the disease are discussed.

Adult↗
PubMed1996

Subtilisin BPN' variants: increased hydrolytic activity on surface-bound substrates via decreased surface activity.

Site-directed mutagenesis and random mutagenesis were used to produce variants of subtilisin BPN' (Bacillus amyloliquefaciens) protease with variable surface adsorption properties. Protease adsorption and peptide hydrolysis rate were measured for these variants using a model substrate consisting of a peptide covalently bound to a surface. While most variants adsorb at a level very similar to that of native BPN', several variants were identified which adsorb either more or less. For surface-bound substrates we report a linear dependence between the concentration of adsorbed protease enzyme and substrate hydrolysis, similar to the linear dependence between enzyme solution concentration and hydrolysis of soluble substrates. On the basis of this knowledge we hypothesized that variants designed to adsorb at a higher level on a surface-bound peptide substrate would hydrolyze that surface-bound substrate faster. Contrary to our original expectations, the variants that adsorb more on the covalently bound peptide surface hydrolyze this substrate slower. In addition, variants of BPN' which adsorb at a lower level than native BPN' hydrolyze the surface-bound substrate faster. Enzyme adsorption and the subsequent peptide hydrolysis are altered by substituting amino acids that modify the surface charge or hydrophobicity of the native enzyme. This effect is most dramatic when the changes were made at surface-exposed sites around the binding pocket/active site of the enzyme. One mechanism that is consistent with the data is based on the relationship between the level of adsorption and the enzyme's affinity for the surface. In this mechanism weakly adsorbed enzymes are postulated to move more rapidly from site to site on the surface, thereby increasing substrate hydrolysis.

Adsorption↗
PubMed1994

Correlation of end-tidal CO2 measurements to arterial PaCO2 in nonintubated patients.

STUDY OBJECTIVE: To determine the accuracy of end-tidal carbon dioxide levels as a measure of arterial carbon dioxide levels in nonintubated patients presenting to an emergency department for care. DESIGN: A prospective, cross-sectional analysis. SETTING: University hospital ED. TYPE OF PARTICIPANT: Nonintubated adult patients presenting to the ED for care of a variety of problems. INTERVENTIONS: Patients who had arterial blood gas samples taken as part of their ED evaluation were asked to breathe normally through an endotracheal tube adapter or a modified nasal cannula connected to a side port sampling capnometer while a sample for arterial blood gas was drawn from the radial artery. MEASUREMENTS: End-tidal carbon dioxide levels (mm Hg) were recorded at the time of arterial blood gas sampling. The difference between end-tidal carbon dioxide and PaCO2 was tested with the paired t-test at a significance level of .05. The correlation of end-tidal carbon dioxide to PaCO2 was tested in all patients and in subgroups using simple linear regression. RESULTS: Seventy-six patients were enrolled. In all patients, end-tidal carbon dioxide was 3.5 mm Hg lower than PaCO2 and correlated well with PaCO2 (r2 = .772). In patients with hypocapnia, there was no significant difference between end-tidal carbon dioxide and PaCO2 (P = .17), and the correlation of end-tidal carbon dioxide to PaCO2 was stronger (r2 = .838). In patients with a respiratory or metabolic acidosis, the difference between end-tidal carbon dioxide and PaCO2 was 6 mm Hg (P = .005), but end-tidal carbon dioxide correlated well to PaCO2 (r2 = .899). CONCLUSION: Measurements of end-tidal carbon dioxide concentrations correlate well with PaCO2 values in nonintubated patients presenting with a variety of conditions to EDs. End-tidal carbon dioxide measurements may be sufficient measures of PaCO2 in selected patients and obviate the need for repeat arterial blood gas determination. Further study is warranted.

Breath Tests↗
PubMed1991

Cocaine-induced iritis.

The case of a 31-year-old man who presented to the emergency department with iritis from intranasal cocaine use is described. This was the second episode of iritis in this patient after casual cocaine use. The differential diagnosis of iritis and a proposed pathophysiologic mechanism are discussed.

Adult↗