Evangelos Georgiou

Body composition changes in chronic hemodialysis patients before and after hemodialysis as assessed by dual-energy x-ray absorptiometry

The aim of this study was to investigate the effect of hemodialysis on body composition assessment by dual-energy x-ray absorptiometry (DEXA). Seventeen patients with chronic renal failure who were on a regular hemodialysis schedule were studied. Body weight and body composition were assessed immediately before and approximately 1 hour after a typical hemodialysis session. Body weight was assessed by means of an electronic balance. Body composition measurements were made by DEXA. Whole-body and subtotal (head and neck excluded) analysis assessed the following parameters: body weight, bone mineral density (BMD), bone mineral content (BMC), and fat (FTM) and lean (LTM) tissue mass. BMC, FTM, and LTM were estimated separately for the trunk, arms, and legs. The mean body weight reduction after hemodialysis was 2.8 +/- 1.1 kg (mean +/- SD). Concerning whole-body analysis, no change was observed in mean BMC and FTM after hemodialysis. On the contrary, a significant reduction was observed in mean body weight as assessed by DEXA (before hemodialysis, 65.0 +/- 11.4 kg; after, 62.2 +/- 10.9 kg, P = .0003), as well as in mean LTM (before hemodialysis, 42.7 +/- 9.4 kg; after, 39.7 +/- 9.0 kg, P = .0003). Similar results were obtained from subtotal and regional analysis. Body weight changes as measured by the electronic balance exhibited a strong positive correlation with the changes in both body weight and LTM as assessed by DEXA (r = .989, standard error of the estimate [SEE] = 0.167 kg and r = .941, SEE = 0.382 kg, respectively, P < .0001). It is concluded that gravimetric changes induced by hemodialysis are highly correlated with LTM changes and are not associated with changes in BMC or FTM estimated by DEXA.

Sex Hormones in Postmenopausal Women with Breast Cancer on Tamoxifen

In 42 postmenopausal women with breast cancer aged 48-85 (mean age 62.4) years, the blood sex hormone levels were measured before and after 6 months of tamoxifen administration (20 mg daily). Follicle-stimulating hormone and luteinizing hormone levels decreased after tamoxifen administration (p < 0.001), but remained in the postmenopausal range, oestradiol levels increased (p < 0.05), sex hormone binding globulin levels increased (p < 0.001), testosterone levels remained stable (p > 0.1), free testosterone levels decreased (p < 0.001), delta4-androstenedione, 17-hydroxyprogesterone, and dehydroepiandrosterone sulfate levels remained unchanged (p > 0.1), and basal prolactin levels and their response to thyrotrophin-releasing hormone injection decreased significantly (p < 0.001) after tamoxifen therapy. It is concluded that tamoxifen has many and diverse effects on sex hormone levels, and its adverse effects do not affect the biological status of the patient, except perhaps for oestradiol, that increases in some cases, whose possible effect must be studied.

Body composition assessment by dual-energy X-ray absorptiometry : Comparison of prone and supine measurements

The aim of the study was to assess whether changes in the interposition of body compartments affect the results of body composition measurements by dual-energy x-ray absorptiometry (DEXA) in the fan-beam mode. Thirty healthy subjects underwent two sequential measurements: the first was performed in the supine position as described by the manufacturer, and the second in the prone position. Estimates of body composition were compared between the two measurements. Mean body weight did not differ between measurements ([mean+/-SD] supine vprone, 68.561+/-12.461 v 68.589+/-12.469 kg). Mean bone mineral content (BMC) was lower in the prone position versus the supine position. When the head was excluded, this difference reached statistical significance (supine v prone, 1,738+/-361 v 1,688+/-360 g, P=.0001). The mean fat tissue mass (FTM) was lower and lean tissue mass (LTM) higher in the prone measurements. When the head was excluded, the mean FTM difference between the two measurements became greater (FTM supine v prone, 25.129+/-10.445 v 24.030+/-10.388 kg, P=.0001; LTM supine v prone, 37.309+/-9.357 v 38.246+/-9.150 kg, P=.0001). It is concluded that the positioning of the patient on the examination table affects DEXA body composition measurements by the fan-beam mode. This could imply a lack of accuracy of the method, which may be due to subtle changes in regional tissue depth and fat distribution caused by patient repositioning.

Bone mineral loss related to menstrual history

We measured the bone mineral content (BMC) of the forearm in 173 normal postmenopausal women. We also examined the relation between BMC and the chronologic age, the number of years elapsed since menopause, and the total number of menstrual cycles during the reproductive years. BMC had a better linear relation to the total number of menstrual cycles than with the years elapsed since menopause or with chronologic age.

Blood pressure elevation after phenylephrine infusion may adversely affect myocardial perfusion in patients with coronary artery disease.

BACKGROUNDnAlthough blood pressure is a major determinant of myocardial oxygen-demand, little information is currently available regarding the changes in blood pressure (BP) during myocardial ischemia. Since BP elevation may cause left ventricular (LV) wall stress and an increase in oxygen demand, infusion of an alpha-adrenergic agonist, such as phenylephrine (PH), may provoke changes in myocardial perfusion in coronary artery disease (CAD) patients. As the effects of BP changes alone on myocardial perfusion have never been assessed by thallium-201 (Tl) scintigraphy, we investigated the effects of BP elevation after PH infusion, in order to study the hypothesis that pressure loading alone without increases in heart rate, may provoke transient impairment of regional myocardial perfusion, in CAD patients.nnnPATIENTS AND METHODSnForty-one (41) patients with angiographically documented CAD, aged 54+/-8 years, were included in our study. Each patient was given, without any complications, a PH (0.1 mg/ml) dose infused at a rate of 0.8 ml/mm, determined by a standardisation procedure and producing a mean blood pressure elevation of approximately 30% above baseline levels and a heart rate response to levels of no less than 50 bpm. One minute after the desired blood pressure and heart rate responses were reached, 2 mCi of Tl were injected and the PH infusion continued until the termination of the test. Tl scintigraphy was performed both 2 min after Tl injection and 4 h later, while the results were correlated to coronary angiography findings.nnnRESULTSnPH scintigraphy produced 152 total defects. The mean perfusion defect size (%) was 14+/-12 and was directly related to the number of diseased vessels, i.e., 2% for one-vessel disease, 15% for two-vessel disease and 25% for three-vessel disease (P<0.05). The lowest percentage Tl activity values were 56+/-14 and were inversely related to the number of diseased vessels (P<0.01). The mean Tl lung counts/pixel values were 25+/-8 while it increased as the number of diseased vessels increased (P<0.01). The mean lung/heart ratio values were 0.31+/-0.08 while it increased as the number of diseased vessels increased (P<0.01).nnnCONCLUSIONnBP elevation after PH loading, produces a significant impairment of myocardial perfusion, that correlates well with the extend of angiographic findings.

Fast myocardial perfusion imaging with (99m)Tc in challenging patients using conventional SPECT cameras.

BackgroundWe attempted to validate the performance of a fast myocardial perfusion imaging (MPI) protocol in diagnostically challenging patients.Methods78 patients with ΒΜΙxa0>xa024.9, LVH or three vessels disease underwent two sequential gated-MPI studies. The first at 15 (Early Imaging, EI) and the second at 45 (Late Imaging, LI) minutes post 99mTc-injection, at both stress and rest. Counts over heart (H), liver (Liv) and subdiaphragmatic space (Sub) and image quality, and myocardial perfusion and function parameters were compared between the two protocols. Coronary angiography was performed within 2xa0months from MPI, and ROC analysis was used to compare the diagnostic accuracy for the detection of ≥50% diameter luminal stenosis.ResultsQuality was optimal-good in 93% of EI and 98% of LI studies (Pxa0=xa0.12), H/Liv and stress H/Sub ratios were similar, but rest H/Sub ratio was lower in EI (Pxa0=xa0.009). SSS [10 (0 to 46) vs 9 (0 to 36), Pxa0=xa0.006] and SDS [3 (0 to 35) vs 2 (0 to 34), Pxa0=xa0.02] were higher in EI protocol. LVEF, motion and thickening scores did not differ between the two protocols. A highly significant (Pxa0<xa0.001) linear relationship with clinically negligible mean differences in Bland-Altman analysis was observed for all perfusion and function-related data. Sensitivity (EI 81%, LI 80%) and specificity (65% for both) did not differ (Pxa0=xa0.23) between the two protocols.ConclusionThe fast protocol is technically feasible and diagnostically accurate compared to the established protocol in diagnostically challenging patients.

Coronary artery disease: changes of blood lymphocyte subsets induced by physical exercise

To examine the changes in the absolute numbers of blood lymphocyte subsets in patients with coronary artery disease, we studied 26 patients with documented coronary artery disease (group I) and 15 other subjects (group II) with atypical complaints and negative exercise test who served as controls. Blood lymphocyte subsets were determined at rest, immediately and 24 h after a bicycle exercise test. In both groups the absolute number of leukocytes/mm3 and lymphocytes/mm3 was significantly greater immediately after exercise than at rest and returned to baseline values by 24 h post-exercise. The absolute number of B-lymphocytes and CD8+ T-lymphocytes did not change significantly in both groups, while CD3+ and CD4+ T-lymphocytes as well as CD25+ activated T-lymphocytes declined insignificantly immediately after exercise but increased significantly 24 h after exercise in both groups, with a higher increase (P<0.01) in all three variables under study (CD3+, CD4+ and CD25+ T-lymphocytes) in group I in comparison to group II (P<0.05). Our findings showed that changes in lymphocyte subsets induced by physical exercise differ between patients with and without documented coronary artery disease, suggesting that an alteration in immune function may account for these differences.