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Biomedical subjects

J M Hodgson

Publications and source records attributed to J M Hodgson.

At least 37 records · Page 2Linked to original sources
PubMed1999

Effects on blood pressure of drinking green and black tea.

BACKGROUND: The flavonoid components of tea have been associated in epidemiological studies with a decreased risk of cardiovascular disease. Flavonoids have been shown to have antioxidant and vasodilator effects in vitro; we therefore postulated that drinking green or black tea attenuates the well-characterized acute pressor response to caffeine and lowers blood pressure during regular consumption. OBJECTIVE: To determine whether green and black tea can attenuate the transient pressor effect of caffeine, or lower blood pressure during regular consumption. METHODS: In the first study, the acute effects of four hot drinks - green tea and black tea (at a dose equivalent to four standard cups), water matched to the teas for caffeine content ('caffeine') and water - were assessed in 20 normotensive men using a Latin-Square designed study. Clinic blood pressure was measured before and 30 and 60 min after each drink had been ingested. In the second study, the effects on blood pressure of regular green and black tea ingestion were examined in 13 subjects with high-normal systolic blood pressure and mild systolic hypertension (systolic blood pressure in the range 130-150 mmHg) using a three-period crossover study. Five cups per day of green tea, black tea and caffeine (in hot water and matched to the teas) were consumed for 7 days each, in random order. Twenty-four hour ambulatory blood pressure was measured at the end of each seven-day intervention. Results are presented as means and 95% confidence intervals (CI). RESULTS: An acute pressor response to caffeine was observed. Relative to caffeine, there were further acute increases in systolic and diastolic blood pressure at 30 min among those drinking green tea [5.5 mmHg (95%CI -1.4 to 12.4) and 3.1 mmHg (95%CI -0.1 to 6.3), respectively] and black tea [10.7 mmHg (95%CI 4.0 to 17.4) and 5.1 mmHg (95%CI 1.8 to 8.4), respectively]. The changes in blood pressure at 60 min were not significant The effect on 24-h ambulatory systolic and diastolic blood pressure of regular drinking of green tea [increases of 1.7 mmHg (95%CI -1.6 to 5.0) and 0.9 mmHg (95%CI -1.3 to 3.1), respectively] or black tea [increase of 0.7 mmHg (95%CI -2.6 to 4.0) and decrease of 0.7 mmHg (95%CI -2.9 to 1.5), respectively] was not significant relative to caffeine. CONCLUSIONS: Contrary to our initial hypothesis, tea ingestion caused larger acute increases in blood pressure than caffeine alone. However, any acute effects of tea on blood pressure did not translate into significant alterations in ambulatory blood pressure during regular tea consumption.

Adult↗
PubMed1998

Platelet fatty acids and peripheral blood lymphocyte subsets in an institutionalized elderly population.

The associations between platelet fatty acids and peripheral blood lymphocyte subsets were studied in 78 institutionalized elderly individuals (27 men and 51 women), aged 67 to 100. Platelet fatty acids were assessed by gas chromatography, and peripheral blood lymphocyte subsets were quantitated by immunophenotyping using flow cytometry. It was found that women had a higher number of total T-cells (CD3), T-helper (CD3+4+) cells, and B-cells (CD19). However, no gender differences were observed in the percentages of lymphocyte subsets. In elderly men, after adjusting for age and fatty acid intake, the platelet concentration of omega-3 polyunsaturated fatty acids was positively related to the percentage of CD3 and CD3+4+ bearing lymphocytes (rs = 0.59, P < 0.05; and rs = 0.55, P < 0.05, respectively), and the concentration of total saturated fatty acids was also positively associated with the percentage of B (CD19) cells (rs = 0.50, P < 0.05). However, similar relationships were not observed in elderly women. No significant associations were found between trans fatty acids and any of the lymphocyte subsets in the study population. These findings suggest that fatty acids may be related to immune function. Any effects may be important in the host immune defence, especially in elderly individuals.

Aged↗
PubMed1998

Supplementation with isoflavonoid phytoestrogens does not alter serum lipid concentrations: a randomized controlled trial in humans.

Isoflavonoids are a class of flavonoids that are derived in the human diet mainly from soybean-based foods. The major dietary isoflavonoids, genistein and daidzein, have estrogen-like activity and are classed as phytoestrogens. Because estrogens can lower serum LDL cholesterol and raise HDL cholesterol, the objective of this study was to determine if isoflavonoids could improve serum lipids in healthy subjects. Forty-six men and 13 postmenopausal women not receiving hormone replacement therapy completed a randomized, double-blind, placebo-controlled trial of two-way parallel design and 8 wk duration. One tablet containing 55 mg of isoflavonoids (predominantly in the form of genistein) or one placebo tablet was taken daily with the evening meal. Subjects maintained their usual diet and physical activity, which were unchanged throughout the intervention. Measurement of isoflavonoids and their metabolites in 24-h urine samples provided an assessment of compliance and of isoflavonoid metabolism. Serum total, LDL, HDL and HDL subclass cholesterol, triglycerides and lipoprotein (a) were assessed at baseline and during the last week of intervention. After adjustment for baseline values, no significant differences in postintervention serum lipid and lipoprotein (a) concentrations between groups were identified. Further adjustment for age, gender and weight change did not alter the results. In addition, changes in urinary isoflavonoids were not significantly correlated with changes in serum lipids and lipoprotein (a). Therefore, this study does not support the hypothesis that isoflavonoid phytoestrogens can improve the serum lipids, at least in subjects with average serum cholesterol concentrations.

Adult↗
PubMed1997

Improved procedural results of coronary angioplasty with intravascular ultrasound-guided balloon sizing: the CLOUT Pilot Trial. Clinical Outcomes With Ultrasound Trial (CLOUT) Investigators.

BACKGROUND: Indiscriminate use of balloons larger than the angiographic reference segment lumen results in high rates of ischemic complications after percutaneous transluminal coronary angioplasty (PTCA). We hypothesized that angiographically unsuspected atheromatous remodeling with vessel expansion (the Glagov phenomenon) at and adjacent to PTCA target lesions would safely accommodate oversized balloons in selected patients undergoing PTCA with intravascular ultrasound (IVUS) guidance. METHODS AND RESULTS: After angiographically guided PTCA of 104 lesions in 102 patients, IVUS was performed, and if atheromatous remodeling was present, PTCA was repeated with larger balloons sized halfway between the lumen and external elastic membrane. Plaque occupied a mean of 51+/-15% of the angiographically "normal" reference segments. Further balloon upsizing by 0.25 to 1.25 mm was therefore performed in 76 lesions (73%), increasing the nominal balloon-to-artery ratio from 1.12+/-0.15 after standard PTCA to 1.30+/-0.17 after IVUS-guided PTCA (P<.0001). As a result, the angiographic minimal luminal diameter further increased from 1.95+/-0.49 to 2.21+/-0.47 mm, the % diameter stenosis fell from 28+/-15% to 18+/-14%, and the IVUS lumen area rose from 3.16+/-1.04 to 4.52+/-1.14 mm2 (all P<.0001). The incidence of angiographic dissection was not increased after IVUS-guided balloon upsizing (37% versus 40%, P=.67), and major complications occurred in only 2 patients (1.9%). CONCLUSIONS: The demonstration by IVUS of atheromatous remodeling permits the safe use of balloons traditionally considered oversized, resulting in significantly improved luminal dimensions without increased rates of dissection or ischemic complications.

Aged↗
PubMed1997

Single device approach to ultrasound-guided percutaneous transluminal coronary angioplasty and stenting: initial experience with a combined intracoronary ultrasound/variable diameter balloon.

We evaluated the use of both intracoronary ultrasound (ICUS) information and unique balloon characteristics provided by a combined ICUS/variable diameter balloon catheter during coronary interventions to achieve the maximal residual lumen using the least number of devices. In 47 patients, 64 coronary lesions were treated with either sequential percutaneous transluminal coronary angioplasty (PTCA) (n = 40) or stenting (primary [n = 17], secondary [n = 7]). The result after PTCA was judged satisfactory if the lumen cross sectional area (by ICUS) in the lesion exceeded 65% of the mean reference area. Stent implantation was judged according to revised MUSIC trial criteria. PTCA or stenting was successful in all 64 lesions using 47 combination devices and 10 conventional balloons (mean number of balloons per lesion: 0.90). PTCA group: diameter stenosis decreased from 78 +/- 11 to 23 +/- 13% following inflation at 10.3 +/- 3.0 atm. ICUS lumen area was 4.6 +/- 1.9 mm2 (proximal reference: 7.4 +/- 3.3 mm2, distal reference: 5.7 +/- 1.8 mm2) resulting in a residual area stenosis of 28 +/- 15%. Stent group: diameter stenosis was reduced from 77 +/- 14 to 10 +/- 10% after stenting. ICUS defined minimal lumen area in the stent was 8.2 +/- 2.2 mm2 (proximal reference: 8.7 +/- 2.6 mm2, distal reference: 8.0 +/- 2.2 mm2) resulting in a residual area stenosis of 7.2 +/- 14.6%. No patient death, myocardial infarction, or emergency surgery occurred and only one target lesion required re-PTCA during hospitalization. In conclusion, use of a combined ICUS/variable diameter balloon catheter allows a single device strategy for ICUS-guided PTCA and stenting in the majority (84%) of unselected lesions.

Adult↗
PubMed1997

Focal angioplasty: theory and clinical application.

Percutaneous transluminal coronary angioplasty (PTCA) has been performed with 20 mm long uni-diameter balloons for over 17 years with excellent results. It has now become possible to combine both compliant and non-compliant balloon material on a single device, allowing the interventionalist to direct the force of dilation to the lesion focally. This concept has been termed "focal angioplasty." This article reviews the concept of focal angioplasty, including the physics of balloon dilation, and describes current clinical applications for focal angioplasty. We discuss use of the focal angioplasty technique for PTCA and stenting and review the results of several ongoing clinical trials. While the acute results using focal angioplasty have been promising, long-term benefits have not been fully studied and will require completion of ongoing trials.

Angioplasty, Balloon, Coronary↗
PubMed1996

Comparison of tissue disruption caused by excimer and midinfrared lasers in clinical simulation.

Laser coronary angioplasty is a useful therapy for selected complex coronary lesions. Laser-induced acoustic trauma is postulated to be a cause of dissection and acute vessel occlusion. Controversy exists regarding the relative degree of photoacoustic effects of midinfrared and excimer lasers in clinical practice. To date, these systems have not been compared at clinical energy doses and with clinical pulsing strategies. Therefore, we studied the photoacoustic effects of both midinfrared and excimer lasing at clinically accepted doses. Human atherosclerotic iliofemoral artery segments were obtained at autopsy (n = 36) and placed lumen side up in a saline bath. Clinical laser catheters were advanced over an 0.018" guide wire, perpendicular to the tissue. A 10-g down force was applied to the catheter for full-thickness lasing. Pulsing strategies were, for midinfrared laser: 5 pulses, 1-sec pause, 5 pulses, 1-sec pause, 5 pulses, withdraw; for excimer: 5 sec of pulses, wait 10 sec, 5 sec of pulses. Several clinically acceptable energy levels were used; for excimer: 25 mJ/mm2, 40 mJ/mm2, 60 mJ/mm2; for midinfrared: 3 W (400 mJ/mm2), 3.5 W (467 mJ/mm2). Photoacoustic effect was assessed histologically by determining the number of lateral cleavage planes (dissections) arising from the lased crater border and extending into the surrounding tissue. In normal tissue, midinfrared lasing produced less acoustic damage than excimer lasing (2.79 +/- 0.78 vs. 5.27 +/- 0.75 cleavage planes, mean +/- SD, P < 0.05, data for lowest energy for each system). The same was true in noncalcified atheroma (2.48 +/- 0.71 vs. 6.43 +/- 1.09, P < 0.05) and calcified atheroma (2.47 +/- 1.21 vs. 6.27 +/- 1.13, P < 0.05). This effect was similar at all energy levels, with a trend for more damage at higher energies in both systems. This study demonstrates that midinfrared lasing causes less acoustic damage than excimer lasing when using clinical catheters, energy levels, and pulsing strategies. This effect is independent of tissue-type but tends to be dose-related. These findings may explain, in part, the differences in dissection rates seen clinically.

Angioplasty, Balloon, Laser-Assisted↗
PubMed1996

Platelet trans fatty acids in relation to angiographically assessed coronary artery disease.

Epidemiological and metabolic studies indicate that a higher intake of trans fatty acids (TFA) may be associated with increased risk of coronary heart disease (CHD). In a cross-sectional study of patients who underwent coronary angiography, the relationships between TFAs, measured in platelets, and the degree of coronary artery disease (CAD) were examined in 191 non-diabetic patients (134 men and 57 women). The degree of CAD was quantified by using an angiographic scoring system developed to provide an estimate of the extent of coronáry atherosclerosis: an "extent score'. The TFA composition of platelets, including palmitelaidic (16:1 omega 7t), elaidic (18:1 omega 9t), trans-10-octadecaenoic acid (18:1 omega 8t), trans vaccenic (18:1 omega 7t), trans-12-octadecaenoic acid (18:1 omega 6t) and linoelaidic (18:2 omega 6tt) acids, was measured by using gas chromatography and quantified as a percentage of total fatty acids. After adjustment for established CHD risk indicators, including age, gender, cigarette smoking, hypertension and serum total cholesterol concentration, elaidic acid (P = 0.0300) and trans-10-octadecaenoic acid (P = 0.0434) were positively associated with the extent score of CAD. The adjusted associations between other individual TFAs, including palmitelaidic acid (P = 0.1189), vaccenic acid (P = 0.7651), trans-12-octadecaenoic acid (P = 0.0582) and linoelaidic acid (P = 0.8793), and the extent score were not significant. The results of this study, therefore, provide evidence for an association between particular platelet TFAs and the degree of CAD in the patient population studied.

Adolescent↗
PubMed1996

Increased left ventricular dysfunction in elderly patients despite successful thrombolysis: the GUSTO-I angiographic experience.

OBJECTIVE: This study sought to determine whether the recovery of regional and global left ventricular function is reduced in elderly patients despite successful thrombolytic therapy for acute myocardial infarction. Comparisons were made between elderly (> or = 75 years old, n = 47) and adult (< 75 years old, n = 434) patients enrolled in the Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries (GUSTO) angiographic trial who underwent catheterization at 90 min and 5 to 7 days after thrombolysis and who had an open infarct-related artery with Thrombolysis in Myocardial Infarction (TIMI) grade 2 to 3 flow at both times. BACKGROUND: The morbidity and mortality of acute myocardial infarction is increased in elderly patients, presumably because of multiple adverse coexistent baseline variables. However, functional recovery after thrombolysis has not been characterized in the elderly. METHODS: Ejection fraction, end-systolic volume index, infarct and noninfarct zone contractile function (SD/chord) and infarct extent (number of chords) were determined. RESULTS: At 90 min, elderly patients with an open infarct-related artery had decreased infarct zone contractile function (-2.8 +/- 0.2 vs. -2.3 +/- 0.1 SD/chord in adults, p < or = 0.05) and a greater extent of injury (26.0 +/- 2.6 vs. 20.7 +/- 0.8 chords in adults, p < or = 0.05). At 5- to 7-day follow-up ventriculography, ejection fraction was reduced, and end-systolic volume index was significantly increased in elderly patients compared with adults. The severity of regional wall motion dysfunction in the infarct zone was also greater in the elderly than in adults at 5- to 7-day follow-up (-2.6 +/- 0.2 vs. -1.9 +/- 0.1 SD/chord, respectively, p < or = 0.005). Non-infarct zone contractile function at 90-min ventriculography was similar in both groups. Despite a patent infarct-related artery at 90-min, the 30-day mortality rate in the elderly remained elevated (17.8%) compared with that of adults (4%) (p < or = 0.0001). Elderly patients were predominantly female and had a higher prevalence of hypertension, multivessel coronary disease, previous infarction, anterior infarctions and later time to treatment (between 3 and 6 h) than adults. However, age > or = 75 years remained an independent determinant by multivariable regression analysis of 1-week postinfarction end-systolic volume index, regional left ventricular dysfunction (p = 0.02 and p < or = 0.008, respectively) and 30-day mortality (p < or = 0.0001). CONCLUSIONS: Elderly patients had increased damage in the infarct zone and had persistently increased mortality despite sustained infarct-related artery patency after successful thrombolysis. Although the causes are probably multifactorial, a more rapid progression of ischemic injury or a blunted postreperfusion recovery appears to contribute to the poorer outcomes in elderly patients.

Adult↗
PubMed1995

Coronary artery plaque morphology in stable angina and subsets of unstable angina: an in vivo intracoronary ultrasound study.

Little information is available regarding the in vivo composition of angina producing culprit atherosclerotic lesions in various anginal syndromes. In this study we used intracoronary ultrasound to determine the composition of culprit lesions in various subsets of anginal syndromes and correlated this composition with the patient's clinical presentation. One hundred and forty six patients referred for angioplasty or atherectomy were classified as having either chronic stable angina (angina which was clinically unchanged for > 2 months), crescendo angina (an accelerating pattern of frequent or prolonged anginal episodes), severe rest angina (abrupt onset of prolonged angina) or post-infarction angina (angina within 2 weeks of acute myocardial infarction). Intracoronary ultrasound imaging of the culprit lesion was performed before intervention. Lesions were classified as soft, mixed fibrous without calcium, mixed fibrous with calcium or calcified. Analysis of the ultrasound images revealed that the majority of culprit lesions were soft in severe rest (71%) and post-infarction angina (73%) whereas, the majority of culprit lesions were mixed fibrous or calcified in chronic stable (69%) and crescendo (53%) angina (X2 = 22.73, p = 0.007). In addition, the frequency of intralesional calcium in chronic stable or crescendo angina was significantly higher than that in severe rest or stable angina. We conclude that the composition of culprit lesions in various anginal subsets are different. The lesion morphology in crescendo angina frequently resembles that in chronic stable angina; while those in severe rest and post-infarction angina are frequently similar. These findings may have implications for medical or interventional treatment of patients with angina.

Aged↗
PubMed1995

Intracoronary ultrasound-defined plaque composition: computer-aided plaque characterization and correlation with histologic samples obtained during directional coronary atherectomy.

The ability to classify lesion composition accurately may be important for selecting or guiding interventional therapy and for understanding the pathophysiologic basis of individual lesions. To assess the usefulness of ultrasound in classifying lesions, intracoronary ultrasound images were obtained from 44 atherosclerotic lesions in patients before directional atherectomy. Lesions were classified by visual analysis and by computer-assisted gray-level statistics. Atherectomy samples were evaluated histologically for elastosis and calcium and quantitatively by morphometric analysis for various tissue components. The computer-assisted quantitative classification agreed well with the findings on visual analysis. Visual and computer-assisted quantitative ultrasound images were found to have distinctive histologic features. Lesions with predominantly echogenic plaque had a larger fraction of dense fibrous, elastic, or calcified tissue. Lesions with predominantly echolucent soft plaque had a greater fraction of loose fibrous, smooth-muscle, thrombotic, or necrotic elements. Thus intracoronary ultrasound allows accurate classification of lesion composition in patients.

Atherectomy, Coronary↗
PubMed1995

Oral habits and TMJ dysfunction in facial pain and non-pain subjects.

Multifactorial theories for facial pain aetiology have been proposed in the past, although little research has been produced to support a multifactorial aetiology. The present study assessed self-rated oral habits over a 7 day period for facial pain and non-pain subjects with and without a clinical symptom of TMJ dysfunction. The results indicate a significant effect for TMJ dysfunction and teeth clenching and an interaction between TMJ dysfunction and facial pain for biting of the lips and mouth. A significant chi-square test showed that most non-pain controls with TMJ dysfunction reported that they never clenched. The results are discussed in terms of support for a multifactorial aetiology in some facial pain patients and the need for future research to delineate subgroups of facial pain and non-pain subjects.

Adult↗
PubMed1994

Correlation of intracoronary ultrasound plaque characteristics in atherosclerotic coronary artery disease patients with clinical variables.

It was examined whether intracoronary ultrasound-defined plaque morphology of symptom-producing, severely stenosed, atherosclerotic coronary artery lesions is related to patient-related clinical variables. Data regarding anginal pattern (stable vs unstable), age, sex, history of smoking, diabetes, hypertension, hypercholesterolemia and lesion location were recorded in 146 hemodynamically stable patients referred for clinically indicated balloon angioplasty or directional atherectomy. Intracoronary ultrasound images of the lesions were obtained before and after the intervention. Lesions were classified as soft (homogeneous echoes less dense than adventitia) or hard (bright echoes with or without acoustic shadowing). Eighty-three lesions (57%) were classified as soft and 63 (43%) as hard. Univariate analysis showed anginal pattern, age, vessel location and history of smoking to be significantly related to plaque morphology. Multivariate analysis revealed only anginal pattern, age and vessel location to be independent predictors of plaque morphology. The frequency of echogenic hard plaque was significantly higher in patients aged > 60 years (56 vs 30%; p = 0.001), those with stable angina (69 vs 35%; p = 0.002), and lesions located in the distal arterial segments (68 vs 31%; p < 0.001) than in younger ones, those with unstable angina, and lesions in proximal segments, respectively. Based on previous studies, echogenic hard plaques are likely to be predominantly fibrous or calcific, or both, whereas low-echogenicity soft plaques are likely to be fibrocellular, lipid rich or thrombotic, or a combination. This difference in plaque morphology is probably due to differences in the predominant mechanism of plaque formation (i.e., slow growth vs rupture/thrombosis).(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗