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Biomedical subjects

J Lindsay

Publications and source records attributed to J Lindsay.

At least 109 records · Page 6Linked to original sources
PubMed1989

Usefulness of fish oil supplements in preventing clinical evidence of restenosis after percutaneous transluminal coronary angioplasty.

This study assesses the effect of dietary supplements with high dose omega-3 fatty acid (N3FA) on the frequency of clinical restenosis during the 6 months after successful percutaneous transluminal coronary angioplasty (PTCA). One hundred ninety-four patients (214 significant coronary narrowings) were randomized after successful PTCA to receive conventional medical therapy or to an identical regimen supplemented by high dose N3FA (4.5 g/day). Enrollment required angina pectoris and successful dilatation of all significant coronary narrowings. The subjects were randomly assigned to either no N3FA (control, n = 99) or N3FA supplementation (n = 95). After a 1-week trial period, 11 (group 2) declined further treatment because of side effects. The remaining 84 subjects (group 1) continued N3FA throughout the 6-month period. Monthly clinical follow-up was obtained in all patients. Ninety-two percent of patients had cardiac testing for evaluation of recurrent ischemia. Except for a greater percentage of women in the group refusing N3FA supplementation (group 2), the 3 groups were similar in demographic data, medical history, dietary habits, history of previous PTCA and angiographic characteristics. Of the 194 subjects, 56 had clinical restenosis (45 by cardiac catheterization, 8 by exercise testing and 3 by symptoms alone [refused further clinical testing]). Reocclusion rates were: group 1 19%, group 2 46%, and control 35%. Analysis both in accordance with the principle of intention to treat and for subjects who actually received N3FA revealed a significant effect of N3FA on preventing clinical restenosis (p less than 0.04 and p = 0.008, respectively). These data suggest that high dose N3FA supplements reduce the clinical restenosis rate after successful PTCA.

Angiography↗
PubMed1989

Left ventricular filling patterns in aortic stenosis in patients older than 65 years of age.

Left ventricular (LV) filling patterns in 26 elderly (mean age 81 years) patients with severe aortic stenosis (AS) were evaluated using pulsed-wave Doppler echocardiography. Parameters of LV filling, including the ratio of the peak atrial velocity to the peak early diastolic velocity (A/E ratio) and the percent contribution of active atrial filling to total LV filling (%A), of these patients with AS (group I) were compared with 2 groups presumed to have abnormal LV filling: elderly patients (group II) and hypertensives with increased LV mass (group III), as well as with normal volunteers (group IV). The patients with AS had a broad range of LV inflow velocity patterns (A/E = 0.91 +/- 0.56, range 0.20 to 1.91; %A = 34.3 +/- 16.4, range 3.0 to 65), as compared with the consistently low A/E ratio (0.48 +/- 0.13) and %A (25 +/- 7) in the normal volunteers and the high A/E ratio and %A in the elderly (A/E = 1.48 +/- 0.28, %A = 49 +/- 11) and hypertensive (A/E = 1.41 +/- 0.32, %A = 49 +/- 8) groups. When comparing the data obtained by Doppler with hemodynamics at catheterization, the patients with AS and a high A/E ratio (A/E ratio greater than 1, n = 11) had lower LV mid-diastolic pressures (7 vs 18 mm Hg, p less than 0.001), lower pulmonary artery systolic pressures (33 vs 49 mm Hg, p less than 0.05) and less symptomatic heart failure than those patients with AS and a low A/E ratio (A/E less than 1). The aortic valve area was similar in these 2 subgroups (0.40 vs 0.37 cm2).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1989

Probe angioplasty of total coronary occlusion using an intracoronary Probing Catheter.

Coronary angioplasty (PTCA) of total coronary occlusion is limited by the inability of guidewires and conventional dilating catheters to cross all such lesions. We have therefore developed a technique for PTCA of chronic total coronary occlusions using the ultralow profile "balloon-on-a-wire" Probe. An intracoronary Probing Catheter is used to facilitate crossing the stenosis with a guidewire and then to deliver a Probe into the obstruction for balloon dilatation. This technique was used in 13 patients including six in whom other dilating systems had failed to cross the occlusion. Successful dilatation was performed in nine patients (67%). Among the six patients in whom other dilating systems had failed, dilatation was performed in five using the Probing Catheter technique with a successful outcome achieved in four (67%). The Probing Catheter technique offers a promising new method to apply "balloon-on-a-wire" technology to the dilatation of chronic total coronary occlusions. This method may allow successful dilatation when other dilating systems fail.

Aged↗
PubMed1989

Probe "balloon on a wire" ultra-low-profile coronary catheter: results of PTCA in 107 patients.

A new low-profile "balloon-on-a-wire" angioplasty catheter, the Probe (USCI), was used in 107 patients over a 4-month period. Twenty-nine patients had stable angina, 59 had unstable angina, and 19 had had myocardial infarction (MI) 3 to 15 days prior to the procedure; 71 patients had single-vessel and 36 had multi-vessel disease. In this series, 57 lesions were defined as complex. Successful dilatation was defined as a residual stenosis of less than 30%. Of 132 non-total obstructions, 127 (97%) were successfully dilated. Two distal lesions could not be reached, two lesions could not be crossed by the balloon, and a distal lesion dilatation resulted in acute closure in one case. Of 19 total obstructions, 16 (84%) were successfully dilated (mean residual stenosis 23%). The wire tip was unable to cross the lesion in the three unsuccessful procedures. Seven complications occurred in the series, all involving non-total obstructions: closure of a distal vessel and a side branch caused no clinical symptoms or EKG changes; three local dissections were tacked back with repeat dilatation; and two longitudinal dissections caused no apparent reduction in luminal diameter. The Probe's low-profile and exceptional trackability enabled it to cross very tight lesions with minimal trauma to the vessel wall. The high degree of conformability of the PET balloon minimizes vessel straightening or sheer forces and appears to reduce the potential for dissection. The device may therefore extend the indications and ease of PTCA while reducing complications of the procedure.

Angiography↗
PubMed1989

The application of radionuclide ventriculography to cardiac screening.

Screening asymptomatic individuals for latent coronary disease often requires sequential testing because exercise electrocardiography typically produces more false positive than true positive results in a population with a low prevalence of coronary disease. Cardiac scintigraphy is a technique that may be employed as a confirmatory test in lieu of coronary arteriography to further evaluate the significance of a positive exercise electrocardiogram. Radionuclide ventriculography was employed in 98 asymptomatic individuals who were considered to be at moderate risk of heart disease after risk factor analysis and exercise electrocardiography. Seventeen (17%) patients had an abnormal study and underwent cardiac catheterization. Seven had coronary artery disease, two had cardiomyopathy, and eight were normal. Eighty-one (83%) patients had a normal study. Because the sensitivity of radionuclide ventriculography is 63-80%, it was postulated that 2 to 5 individuals with disease were missed. Thus, from a population with an 11-14% prevalence of disease, two subsets were identified. A large subset in which a prevalence of 2-6% could be estimated was separated from a much smaller one in which a prevalence of approximately 50% was demonstrated.

Adult↗
PubMed1988

Heart rate adjustment of ST-segment depression for reduction of false positive electrocardiographic responses to exercise in asymptomatic men screened for coronary artery disease.

The ability of heart rate (HR) correction of exercise-induced ST-segment depression (the delta ST/HR index) to reduce the number of false positive exercise electrocardiograms during initial screening for occult coronary artery disease (CAD) was examined in active, asymptomatic men from the Army Reserve. Among 606 consecutive men given treadmill tests, 62 asymptomatic subjects with normal results on resting electrocardiograms but abnormal outcomes on standard exercise electrocardiograms underwent rest and exercise radionuclide cineangiography, and the 10 subjects with abnormal radionuclide findings then underwent coronary angiography. A previously established delta ST/HR index less than 1.6 microV/beat/min correctly identified 34 of 52 subjects (65%) who, despite abnormal standard exercise electrocardiographic findings, had no rest or exercise radionuclide abnormalities. A delta ST/HR index greater than or equal to 1.6 microV/beta/min detected 7 of 7 subjects with abnormal radionuclide cineangiograms who had CAD at cardiac catheterization, but also identified 2 of 3 subjects with an abnormal radionuclide test who had no CAD. In contrast to the 7 of 62 subjects (11%) with abnormal standard exercise test criteria who had radionuclide and angiographic evidence of CAD, a delta ST/HR index partition of 1.6 microV/beat/min separated subjects into subgroups with 0% (0 of 35) vs 26% (7 of 27) prevalences of CAD by serial diagnostic evaluation (p less than 0.01). Thus, among asymptomatic subjects with abnormal electrocardiographic responses to exercise, simple HR correction of the magnitude of ST-segment depression reduced by 56% the number of subjects with standard exercise test criteria leading to referral for additional diagnostic evaluation, without loss of sensitivity for angiographically proven CAD and with accurate negative predictive value.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary Angiography↗
PubMed1988

Electrocardiographic diagnosis of left ventricular hypertrophy in the presence of complete right bundle branch block.

There are few data evaluating electrocardiographic diagnosis of left ventricular (LV) hypertrophy in the presence of right bundle branch block (BBB). This study assesses the relative value of multiple electrocardiographic variables for detecting LV hypertrophy in patients with right BBB. LV hypertrophy was defined as LV mass greater than or equal to 215 g calculated from the Penn method using standard M-mode echo measurements. Sixty-two patients were evaluated (ages 41 to 94) and 35 had LV hypertrophy. None of the electrocardiographic criteria was sensitive; the best was mean QRS axis less than or equal to -30 degrees (sensitivity) 52%) and excessive negative P terminal force (sensitivity 28%). Several electrocardiographic variables were specific: Sokolow index greater than or equal to 35 mm (100%), RV5 or RV6 greater than or equal to 25 mm (96.3%), RI + SIII greater than or equal to 25 mm (92.6%) and intrinsicoid deflection greater than or equal to 0.05 seconds (88.5%). Conventional electrocardiographic criteria do not reliably detect LV hypertrophy in the presence of right BBB, but several criteria are relatively specific for LV hypertrophy.

Adult↗
PubMed1988

Results of percutaneous transluminal coronary angioplasty by multiple, relatively low frequency operators: 1986-1987 experience.

The initial results of percutaneous transluminal coronary angioplasty (PTCA) in this institution were described previously and were comparable with national statistics despite the comparatively small number of cases performed by individual physicians. Two years later, the number and complexity of cases have increased significantly. In the present study, the experience of 3 physicians (group 1) who performed greater than 100 PTCAs (143 +/- 35, mean +/- standard deviation) was compared with that of 14 physicians (group 2) who performed less than 100 PTCAs (25 +/- 16) during a recent 12-month period. Group 1 and group 2 performed 430 and 351 PTCAs, with a 91 and 84% success rate, respectively (p less than 0.01). Group 1 and group 2 attempted dilatation of 595 and 444 narrowings with an 85 and 81% success rate, respectively (p less than 0.025). The differences reflect outcomes with "complex lesions," with which group 1 had a higher success rate than group 2 (81 vs 69%, p less than 0.05) and a lower complication rate (3.1 vs 7.5%, difference not significant). Outcomes with "simple lesions" were similar for the 2 groups (93 vs 90%). As a result, the conclusions of the previous study should be modified. The present data suggest that while low frequency operators can perform PTCA of "simple lesions" with quite satisfactory results in the setting of an institution in which large numbers of PTCAs are performed and in which an expert team is available for support, outcomes with "complex lesions" are likely to be better in more experienced hands.

Angioplasty, Balloon↗
PubMed1988

HLA-D region alpha-chain monoclonal antibodies: cross-reaction between an anti-DP alpha-chain antibody and smooth muscle.

Two monoclonal antibodies, Tal 3C3 and Tal 1B5, raised against purified plasma membrane extract of the Bristol 8 B lymphoblastoid cell line and previously shown to recognize epitopes on denatured HLA-D alpha-chains revealed several differences in staining patterns when screened by immunocytochemical techniques on pre-fixed paraffin-embedded sections of human tissues. Although Tal 3C3 staining was weaker and more restricted than Tal 1B5 on immunoregulatory cells expected to express class II antigens, this monoclonal antibody showed additional strong activity on normal smooth muscle. Biochemical studies show that whereas Tal 1B5 reacts with DR alpha-chains, Tal 3C3 predominantly defines DP alpha-chain subunits and a high molecular weight (200-250 kD) actin binding protein known as filamin. In view of several recent reports that the cellular distribution of class II antigens may be more widespread than hitherto thought and may be expressed by cells not normally involved in specific immune functions, these findings emphasize that unexpected monoclonal antibody reactions must be interpreted with caution. It is clearly important to include both immunohistological tissue section and biochemical studies in the initial screening procedures for monoclonal antibodies in order to distinguish between specific target antigen activity and cross-reactions with unrelated molecules.

Antibodies, Monoclonal↗
PubMed1988

Epitope recognition by a DP alpha chain-specific monoclonal antibody (DP11.1) is influenced by the interaction between the DP alpha chain and its polymorphic DP beta chain partner.

The HLA-DP alpha chain-specific monoclonal antibody DP11.1 binds only to the surfaces of cells types as DPw2 or DPw4 by primed lymphocyte typing. To investigate the molecular basis for this antibody binding specificity, we isolated a DPw3 alpha chain cDNA clone and compared its sequence to those of other published DP alpha chain alleles. Interestingly, the extracellular region of the DPw3 alpha chain was identical to the analogous regions of DPw2 and DPw4 alpha chains. Immunoblotting analysis confirmed that the DP11.1 epitope is conserved on denatured DP alpha chains associated with cells typed as DPw2, DPw3, and DPw4. Therefore the binding of antibody DP11.1 to its alpha chain epitope is influenced by the associations between the DP alpha chain and its polymorphic DP beta chain partner.

Amino Acid Sequence↗
PubMed1987

Molecular variation of human major histocompatibility complex DQw3 beta-chains.

Histocompatibility leukocyte antigen DQ molecules exhibit polymorphism of both DQ alpha- and beta-chains. Histocompatibility leukocyte antigen-DQw3 is associated with both DR4 and DR5 and can be further subdivided by reactivity with the monoclonal antibody TA10. To determine the molecular nature of the DQ polymorphic alleles associated with the DR4 haplotype, we have sequenced and analyzed DQ alpha and beta cDNA clones obtained from a DR4, Dw4, DQw3 cell line which is TA10-positive. The DQ alpha-chain sequence was identical to previously published sequences from the DR4 haplotype, but the DQ beta sequence differed from published DR4-DQ beta sequences obtained from DQw3-positive TA10-negative cell lines by eight amino acids, six of which were located in the beta 1 domain. Thus, the TA10 serologic determinants reside on the DQ beta-chain. A TA10-specific oligonucleotide probe was constructed based on the DQ beta sequence, and its specificity was confirmed in a panel of TA10-positive and TA10-negative cell lines. An additional band was observed in Southern blotting experiments which may indicate a donor sequence for gene conversion.

Alleles↗