PubMed Health⌕ Search

Biomedical subjects

K L Richards

Publications and source records attributed to K L Richards.

At least 37 records · Page 2Linked to original sources
PubMed1984

Usefulness of the postexercise response of systolic blood pressure in the diagnosis of coronary artery disease.

The normal decline in systolic blood pressure (SBP) during the recovery phase of treadmill exercise does not occur in some patients with coronary artery disease (CAD). In others the recovery values of SBP exceed the peak exercise values. To examine the diagnostic value of this observation, we studied 31 normal subjects and 56 patients undergoing treadmill exercise before coronary cineangiography. Because of large differences in peak exercise pressures between the two groups, recovery ratios were derived by dividing the SBP at 1, 2, and 3 min after exercise by the peak exercise SBP. The 1, 2, and 3 min ratios in the normal subjects declined steadily from 0.85 +/- 0.07 (SD) to 0.79 +/- 0.06 and to 0.73 +/- 0.06, respectively, while the ratios in the patients with CAD remained elevated at 0.97 +/- 0.12 to 0.97 +/- 0.11 to 0.93 +/- 0.13. With use of the upper limits defined by two SDs of the normal value, recovery ratios were compared with the occurrence of angina and with ST segment depression on the exercise electrocardiogram in the patients with CAD. Abnormal ratios were more frequent in patients with CAD (53/56, 95%) than in those with ST segment depression (33/56, 59%), angina (37/56, 66%), and either ST segment depression or angina (42/56, 75%). Twenty of the patients with CAD who were on no medication underwent an additional treadmill exercise test on a separate day and no significant differences were found in the ratios from the two tests. Ten additional patients with CAD underwent treadmill exercise testing while on placebo and while on a beta-blocker.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗
PubMed1984

A modified microchamber method for chemotaxis and chemokinesis.

A 48 well chemotaxis microchamber, originally designed for use with polycarbonate filters, was used with nitrocellulose filters to quantitate chemotaxis and chemokinesis of granulocytes. Various features of the microchamber were compared to Boyden chambers. The accuracy and reproducibility of the method were found to be comparable to Boyden chambers in the variability between individual readings and superior in the variability between replicate values. Concentrations of optimal doses of chemoattractant for chemotaxis and chemokinesis were similar using both types of chamber. The data indicates that this method may be useful in studying components of the chemotactic response which require the use of cellulose filters. Advantages of this method over standard Boyden chambers include the use of a single filter rather than individual, non-identical filters and a reduction in the number of cells required, particularly for pediatric testing or in neutropenic patients.

Chemotaxis, Leukocyte↗
PubMed1983

Angioplasty catheter communication mimicking coronary arterial dissection.

We report a case in which a sudden communication between the pressure and balloon inflation lumens of a percutaneous transluminal angioplasty (PTCA) catheter angiographically mimicked dissection of the coronary artery. This case illustrates a previously undescribed catheter artifact that must be differentiated from other complications of PTCA.

Aortic Dissection↗
PubMed1983

Noninvasive diagnosis of aortic and mitral valve disease with pulsed-Doppler spectral analysis.

To differentiate normal from abnormal left-sided heart valves, 34 adults (6 normal and 28 abnormal) with 48 valve lesions proved at catheterization were examined using a 3 MHz duplex pulsed Doppler echocardiograph with 2-dimensional verification of sample volume position and on-line display of the Doppler audio spectrum. A uniform protocol was used to position the sample volume for each lesion and to analyze the Doppler spectral data. Intracardiac blood turbulence, manifested by an increased Doppler spectral envelope area, was the noninvasive indicator of disease. The specific lesion present was determined by documenting the intracardiac location and timing of the turbulence. Doppler spectral envelope areas in all normal valve sites were smaller than those measured at the same sites in patients with aortic stenosis, mitral stenosis, and mitral regurgitation (p less than 0.01). Except for a single patient with minimal aortic regurgitation, spectral envelope area allowed complete separation of patients with valve disease from normal subjects (p less than 0.01). High sensitivity (97%) and specificity (100%) were noted despite the presence of multiple valve lesions in 67% of the patients. The data demonstrate application of a simple, noninvasive method of acquiring and analyzing Doppler echocardiographic data which allows accurate identification or exclusion of left-sided valve disease in adults, even in the presence of multiple valve lesions.

Adult↗
PubMed1983

Alterations of the glycocalyx of Fc receptor-bearing cell lines during Fc receptor-ligand interactions.

The binding of IgG-coated erythrocytes to Fc receptors on both a lymphoblastoid and a macrophage-like cell line resulted in a decrease in thickness of the polyanionic, extracellular glycocalyx (cell coat) as determined by electron microscopic histochemistry. This decrease showed no correlation with ligand-binding sites and was considered to be a generalized extramembrane effect. Pretreatment of the cells with trypsin or neuraminidase produced decreases in thickness similar to those observed following ligand binding. The results suggest a possible role for enzymatic cleavage of extracellular constituents by morphologically and functionally different cell types and may represent an event common to cell-surface recognition.

Animals↗
PubMed1982

Digital Fourier techniques in the diagnosis and quantification of aortic stenosis with pulsed-Doppler echocardiography.

Pulsed Doppler echocardiography and digital Fourier analysis were utilized to examine flow distal to the aortic valve and to quantify aortic stenosis. A graphic index of parameters derived from velocity spectrum patterns generated by Fourier analysis was regressed against mean systolic pressure gradients in 21 adults with clinical evidence of aortic stenosis who underwent catheterization studies and five normal adults (r = .82). Correlation improved in the absence of regurgitation (r = .92). Sensitivity for detecting gradients greater than 30 mmHg was 86%; specificity was 90%. Doppler spectral analysis shows promise in alleviating the need for many invasive studies.

Aortic Valve Stenosis↗
PubMed1981

Prevention of contrast-induced bradycardia during coronary angiography.

A double-blind study of 90 patients undergoing coronary angiography was performed to determine the safety and efficacy of 0.6 mg atropine sulfate in preventing contrast-induced bradycardia. Coronary angiography performed using the Sones technique resulted in ventricular pauses of greater than 2 seconds in 3 of 49 patients (6%) who received prophylactic atropine and 20 of 41 patients (49%) receiving placebo. Though the pauses were usually due to atrial asystole, 26% of those with greater than 2 second pauses did so because of transient complete heart block. Prophylactic atropine did increase resting heart rate but did not cause other arrhythmias or increase the frequency of angina pectoris despite the presence of severe coronary disease. Our data indicate that contrast-induced asystole is very common, cannot be predicted by consideration of "precatheterization data," and can be prevented effectively and safely by use of prophylactic atropine sulfate.

Angiography↗
PubMed1981

Predictive value of early postmyocardial infarction modified treadmill exercise testing in multivessel coronary artery disease detection.

We evaluated 57 patients with modified treadmill exercise testing and angiography early post-infarction (MI) to determine the predictive value of ST segment depression, angina, and an inadequate blood pressure response for multivessel coronary artery disease (MVCAD). ST segment depression alone identified MVCAD stenoses (greater than or equal to 70% diameter narrowing in two or more vessels) with sensitivity 54%, specificity 75%, and accuracy 60%. When ST segment depression and angina were considered a positive treadmill test result, a significant improvement in sensitivity (88%, p less than 0.01) and accuracy (82%, p less than 0.05) for MVCAD was observed. An inadequate blood pressure response was associated with MVCAD (12 of 13 patients) and a significantly reduced average left ventricular (LV) ejection fraction of 39 plus or minus 13% compared to 58 plus or minus 14% for patients without this treadmill abnormality (p less than 0.01). Therefore, we conclude that (1) ST segment depression and angina on early post-MI modified treadmill exercise testing are superior predictors of MVCAD compared to ST segment depression alone and (2) an inadequate blood pressure response during modified exercise testing early following MI is observed in patients with MVCAD and reduced LV performance.

Adult↗
PubMed1981

Immunoglobulin E anti-Staphylococcus aureus antibodies in atopic patients.

Sera from 56 patient and normal adults were examined to quantitate total immunoglobulin E (IgE) and IgE antibodies to Staphylococcus aureus and Staphylococcus epidermidis. Patients were divided into six groups based on clinical symptoms; a seventh group consisted of normal adults. Anti-S, aureus IgE binding was significantly higher in three groups of patients (those with eczema, those with or without series staphylococcal abscesses, and allergic patients with staphylococcal skin infections) than it was in the control group. Patients with high IgE due to allergies or parasitic infections without staphylococcal infections and patients with low or normal IgE and serious staphylococcal infection showed low levels of binding. The assay measured specific binding of IgE to bacterial antigens.

Adult↗
PubMed1981

Venous thromboembolism in decompensated chronic obstructive pulmonary disease. A prospective study.

Largely on the basis of postmortem studies, pulmonary emboli have been implicated as an etiologic factor in the acute and chronic respiratory failure of chronic obstructive pulmonary disease (COPD). The diagnosis of pulmonary embolism clinically or by tests directed at the lungs (except pulmonary angiography) is likely to be inaccurate in the presence of COPD because of the underlying abnormalities. We reasoned that by directing tests at the lower extremities to determine the presence or absence of deep venous thrombosis (DVT), we might obtain an accurate reflection of the presence of pulmonary emboli (PE), since virtually all PE are believed to arise in those deep veins. Accordingly, in a group of 45 patients with decompensated COPD, we performed ascending contrast venography (12 patients), 125I-labeled fibrinogen scanning (6 patients), or both (27 patients). Only 2 patients had proximal DVT, which was probably present on admission (4.4%). Two other patients developed DVT (limited to the calf) while hospitalized, (overall incidence of 8.9%). Another patient developed superficial thrombophlebitis during the study but before venography. Noninvasive tests for DVT (Doppler ultrasound and impedance plethysmography) were performed in 40 subjects. A negative result had a high predictive value (94% for each), but contrary to findings in other settings, a positive test had a poor predictive value (Doppler = 33%, IPG = 25%).

Aged↗