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Biomedical subjects

M Elisaf

Publications and source records attributed to M Elisaf.

At least 91 records · Page 5Linked to original sources
PubMed1997

Increased activity of platelet-activating factor acetylhydrolase in low-density lipoprotein subfractions induces enhanced lysophosphatidylcholine production during oxidation in patients with heterozygous familial hypercholesterolaemia.

Patients with heterozygous familial hypercholesterolaemia (FH) have elevated plasma concentrations of low-density lipoprotein (LDL) and develop premature atherosclerosis. There is increasing evidence that oxidative modification of LDL is important for the pathogenesis of atherosclerosis, and the LDL-associated platelet-activating factor acetylhydrolase (PAF-AH) seems to play a key role in LDL oxidation by hydrolysing the oxidized phospholipids of phosphatidylcholine (PC) and producing lysophosphatidylcholine (lyso-PC). We measured the total serum and high-density lipoprotein (HDL) levels of PAF-AH activity and studied the distribution of PAF-AH activity among three LDL subfractions isolated by gradient ultracentrifugation in 15 patients with heterozygous FH and 13 normolipidaemic control subjects. We also determined the lyso-PC production in each LDL subfraction during Cu2(+)-induced oxidation in vitro. The total serum PAF-AH activity in heterozygous FH patients was significantly higher than in control subjects, whereas the HDL-associated PAF-AH activity, expressed as a percentage of total serum PAF-AH activity, was significantly lower in the FH patients than in control subjects (13.9 +/- 6.6% vs. 30.6 +/- 4.4%, P < 0.001). Among the LDL subfractions, the PAF-AH activity in both normolipidaemic control subjects and FH patients, expressed as nmol mg-1 protein min-1, was significantly higher in the LDL3 subfraction (33.1 +/- 4.8 and 53.4 +/- 11.5 respectively) than in the LDL2 (18.6 +/- 5.3 and 26.8 +/- 10.4 respectively, P < 0.0001 for both comparisons) and LDL1 subfractions (5.1 +/- 1.5 and 7.8 +/- 2.6, respectively, P < 0.0001 for both comparisons). Additionally, the enzyme activity in each LDL subfraction of the heterozygous FH patients was significantly higher than in control subjects (P < 0.02 for LDL1, P < 0.03 for LDL2 and P < 0.0001 for LDL3). No difference was observed in the susceptibility to oxidation of each LDL subfraction among the heterozygous FH patients and the normolipidaemic control subjects. During oxidation, the PAF-AH activity decreased, whereas the lyso-PC levels significantly increased in all subfractions of both groups. The lyso-PC/sphingomyelin molar ratio in each LDL subfraction of the FH patients 3 h after the onset of the oxidation was significantly higher than in control subjects [0.38 +/- 0.05 and 0.27 +/- 0.04, respectively, for LDL1 (P < 0.006), 0.47 +/- 0.08 and 0.39 +/- 0.03, respectively, for LDL2 (P < 0.04), 0.55 +/- 0.11 and 0.42 +/- 0.06, respectively, for LDL3 (P < 0.02)]. Our results show that heterozygous FH patients exhibit higher PAF-AH activity than control subjects in all LDL subfractions, resulting in higher lyso-PC production during oxidation, which confers on these subfractions higher biological potency. This phenomenon, in combination with the diminished anti-atherogenic and antioxidant capability of HDL in these patients due to the relatively low HDL-cholesterol levels compared with LDL-cholesterol levels and, consequently, the relatively low HDL-associated PAF-AH activity, could contribute to the higher atherogenicity and incidence of coronary artery disease observed in FH patients.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗
PubMed1997

Hypomagnesemic hypokalemia and hypocalcemia: clinical and laboratory characteristics.

Clinically important electrolyte disturbances such as hypokalemia and hypocalcemia have been well described in patients with hypomagnesemia of various causes. We undertook the present study to describe in detail the clinical characteristics as well as the acid base and electrolyte abnormalities in an effort to better understand the conditions that favor the appearance of this syndrome of hypomagnesemic hypokalemia and hypocalcemia, and the underlying pathogenetic mechanisms. A total of 35 adult patients (23 male, 12 female), aged 21-79 years, who exhibited profound hypomagnesemia, hypokalemia, and hypocalcemia on their admission were studied. The most common causes of the syndrome were alcoholism and cisplatin administration. All but 2 patients with diarrhea had inappropriate magnesiuria. Despite hypokalemia and hypocalcemia all patients exhibited renal potassium and calcium wasting. Eight alcoholic patients with alcohol withdrawal syndrome or acute intoxication had pure respiratory alkalosis, while 6 patients with severe hypokalemia presented with metabolic alkalosis. Three chronic alcoholic patients exhibited metabolic alkalosis coexisting with respiratory alkalosis, while 1 alcoholic patient had the syndrome of alcoholic ketoacidosis. Hyponatremia was evident in only 2 patients with clinical and laboratory evidence of extracellular volume depletion. Hypophosphatemia was observed in 12 patients mainly due to inappropriate phosphaturia. Finally, hyperphosphatemia was found in 2 alcoholic patients with severe respiratory alkalosis. In conclusion, patients with hypomagnesemic hypokalemia and hypocalcemia exhibit multiple interrelated acid base and electrolyte abnormalities and mainly hypokalemia due to inappropriate kaliuresis, hypophosphatemia or rarely hyperphosphatemia, respiratory and metabolic alkalosis, as well as mixed acid base disorders.

Acid-Base Imbalance↗
PubMed1997

Fractional excretion of magnesium in normal subjects and in patients with hypomagnesemia.

The aim of our study was the determination of fractional excretion of magnesium (FEMg++) in both normal subjects and hypomagnesemic patients. 142 subjects aged 26-72 years, recruited from our lipid clinic (control population) and 74 hypomagnesemic patients, aged 36-75 years, were studied. The mean FEMg++ in the control population was 1.8 per cent (range, 0.5-4 per cent). FEMg++ was not correlated with either serum magnesium or with serum creatinine. The mean FEMg++ in patients with hypomagnesemia of extrarenal origin was 1.4 per cent (range, 0.5-2.7 per cent), while the mean FEMg++ in hypomagnesemic patients in whom renal magnesium loss was the main etiologic factor for the pathogenesis of hypomagnesemia was 15 per cent (range, 4-48 per cent). In both groups of hypomagnesemic patients FEMg++ was positively correlated with the urinary magnesium to creatinine molar ratio, but was not correlated with serum magnesium or creatinine levels. FEMg++ could better distinguish the two groups of hypomagnesemic patients than the urinary magnesium to creatinine molar ratio. Hypomagnesemic patients exhibited a cluster of other acid-base and electrolyte abnormalities, mainly respiratory alkalosis, hypokalemia, hypophosphatemia, and hypocalcemia. In conclusion, in hypomagnesemic patients with normal renal function FEMg++ is a very useful tool for the diagnostic approach of hypomagnesemia. A value more than 4 per cent is indicative of inappropriate magnesium loss.

Adult↗
PubMed1996

Lp(a) levels in Greek patients with heterozygous familial hypercholesterolemia.

We undertook the present study to evaluate the lipid profile in 82 (51 male, 31 female) Greek individuals with heterozygous familial hypercholesterolemia (FH), aged 13-61 years from 22 families. FH heterozygotes had significantly elevated serum Lp(a) levels in comparison with 82 normal controls. Serum Lp(a) levels were also increased in FH probands compared to their controls. Additionally, serum Lp(a) concentration was elevated in the FH heterozygotes compared to their unaffected first degree relatives.

Adolescent↗
PubMed1996

Lipid profile in patients with microvascular angina.

Lipid, lipoprotein and apolipoprotein levels, as well as the susceptibility of low-density lipoprotein (LDL) to oxidation, were studied in patients with micro-vascular angina in comparison with patients with coronary artery disease (CAD) and normal subjects. Total cholesterol, LDL-cholesterol and apolipoprotein B levels in microvascular angina patients (235 +/- 46 mg dL-1, 135 +/- 33 mg dL-1 and 146 +/- 32 mg dL-1 respectively) were significantly higher than in control subjects (204 +/- 40 mg dL-1, 116 +/- 35 mg dL-1 and 129 +/- 29 mg dL-1 respectively, P < 0.01). These parameters were also significantly higher in CAD patients than in control subjects. By contrast, high-density lipoprotein (HDL)-cholesterol levels in microvascular angina patients were no different from those in control subjects, although both were significantly higher than in the CAD patients (48 +/- 16 mg dL-1 and 45 +/- 12 mg dL-1 compared with 40 +/- 10 mg dL-1, P < 0.01 and P < 0.05 respectively). Similar results were obtained for the apolipoprotein AI levels. Furthermore, the atherogenic risk ratio, LDL-cholesterol/HDL-cholesterol, in microvascular angina patients was significantly lower than in the CAD patients (3.4 +/- 1.2 vs. 4.1 +/- 1.5 respectively, P < 0.01). Median (range) serum lipoprotein (a) [Lp(a)] levels in microvascular angina patients and CAD patients [13 mg dL-1 (0.8-92) and 16 mg dL-1 (0.8-96) respectively] were significantly higher than in control subjects [7 mg-dL-1 (0.8-44)], P < 0.01 and P < 0.005 respectively. Sigmoidal curves and electrophoretic mobility of the Cu(2+)-oxidized LDL in both microvascular angina and CAD patients were not significantly different from those of control subjects. Finally, no significant differences were found between groups in total triglyceride levels or in very low-density lipoprotein (VLDL), LDL and HDL triglyceride levels. Our results show that the microvascular angina patients exhibit lipid abnormalities similar to those observed in CAD patients, with the important exception of the HDL-cholesterol and apolipoprotein AI levels, which are significantly higher in microvascular angina patients. We suggest that the abnormal cholesterol and Lp(a) levels may be involved in the pathophysiology of microvascular angina by affecting endothelial function and endothelium-mediated vasodilator responses, whereas the higher HDL levels may be a factor contributing to the absence of angiographically documented CAD in microvascular angina patients.

Adult↗
PubMed1996

Smoking habit in female students of northwestern Greece: relation to other cardiovascular risk factors.

THE AIMS OF OUR STUDY WERE: (1) to detect the prevalence of cigarette smoking among female students in Northwestern Greece, and (2) to assess the relation of cigarette smoking with other harmful lifestyles (such as alcohol consumption, obesity, type of dietary fat), fasting lipids and blood pressure. A total of 590 female students in the last class of the local senior high schools was studied. Seventy-seven (13%) of the students were smokers. Interestingly, in this cohort of young female students clustering of the smoking habit with dyslipidemia and alcohol use was observed. However, smoking was associated with significantly lower levels of blood pressure, as well as with lower mean body weight and body mass index. In conclusion, a considerable though apparently decreasing number of Greek female students are smokers. The smoking habit is strongly associated with dyslipidemia and alcohol consumption in this population.

Adolescent↗
PubMed1996

Ambulatory blood pressure monitoring in hemodialysis patients.

The aim of our study was the detection of blood pressure (BP) variability during a dialysis session and in the interdialytic period in normotensive and hypertensive hemodialysis (HD) patients using ambulatory blood pressure monitoring (ABPM). Twenty-two HD patients aged 54 (range, 33-78) years who were on HD for a mean of 17.7 (range, 1-70) months were studied. Twelve patients were hypertensives, while the remaining 10 were normotensives (BP < 140/90 mm Hg). In all patients ABPM was performed for a total of 48 h including an HD session. A significant decrease in systolic BP, diastolic BP and mean BP was observed at the end of a dialysis session in hypertensive HD patients. However, in only five patients a reduction of more than 5% In mean arterial BP was noticed. No significant differences were observed in the BP values between the first and the second day after the HD in hypertensive HD patients. Interdialytic BP (both systolic and diastolic) was significantly higher than the postdialysis BP measured either in the clinic or with the ABPM in these patients. Normotensive HD patients exhibited a normal diurnal variation of BP during the first day after the HD session (decrease in BP during the night). On the second day after the HD session an increase in BP (mainly of systolic BP), as well as a loss of diurnal variation were observed. On the contrary, hypertensive HD patients did not exhibit the normal diurnal variation of BP during the first or the second day after the HD session. Hypertensive HD patients exhibited increased daytime and night time BP loads. On the other hand, normotensive HD patients presented with BP loads within normal limits, even though a small increase in these loads was observed on the second day after dialysis. In conclusion, while hypertensive HD patients present a loss of the normal diurnal variation of BP, normotensive HD patients exhibit normal variation during the first day after the HD session. The loss of the diurnal variation during the second day in these patients suggests a volume-dependent state.

Adult↗
PubMed1996

Ambulatory blood pressure monitoring in normotensive pregnant women.

Ambulatory blood pressure monitoring (ABPM) provides a profile of blood pressure (BP) during daily activities and sleep and could uncover the inter-individual variability of BP. The aims of this study were to establish the normal values of the ABPM during the three trimesters of normal pregnancy, and to compare these values with those obtained in the office. ABPM was carried out on 22 normotensive pregnant women. BP values were compared with those obtained in the office. BP during the third trimester was significantly higher than the BP recorded during the first two gestational periods. In the three trimesters of pregnancy mean ambulatory systolic and diastolic BP were lower than the BP measured in the office in lying and standing positions. On the other hand, mean ambulatory BP (systolic and diastolic) measured during daily activities was not significantly different from the BP measured in the office. Sleeping BP was significantly lower than waking values in all trimesters, while there were not significant differences in the degree of BP fall among the three trimesters. Six women were sequentially studied during the three trimesters of pregnancy and particularly at the 12, 24 and 32 weeks of pregnancy. In these women, a small but significant rise in mean 24 h systolic and diastolic BP was observed at 32 weeks of pregnancy. Sleeping BP was significantly lower than waking values in the three trimesters. No significant difference in the degree of BP fall on the three gestational dates was found. It is concluded that ABPM is a useful tool for the evaluation of BP variability during pregnancy. During normal pregnancy ambulatory BP levels are highest in the day and lowest at night at all gestational ages and increased at the third trimester of pregnancy compared to the values observed during the first two gestational periods.

Adult↗
PubMed1995

Role of the spleen in lipid metabolism.

The frequency of ischaemic heart disease observed after splenectomy for trauma and the low cholesterol levels found in patients with hypersplenism are observations that suggest a possible role for the spleen in lipid metabolism and in the aetiology of atherosclerosis. The present study was designed to examine this role in experimental animals. Serum levels of total cholesterol, triglyceride and high-density lipoprotein (HDL) cholesterol were determined in 32 rats. The spleen was removed in 16 rats and the remaining 16 were sham operated. Half of the splenectomized and half of the remaining rats were fed on a diet rich in fat and the two other subgroups were fed normal chow. Blood tests were performed before, and 3 and 6 months after operation. A significant increase in serum triglyceride and decrease in serum HDL cholesterol levels was observed after splenectomy in rats fed normal chow compared with sham-operated rats. An increase in serum triglyceride and a decrease in serum HDL cholesterol levels was observed in both groups of rats fed normal chow plus high-fat cheese. However, these changes were more pronounced in splenectomized rats. These findings suggest that the spleen has a role in lipid metabolism in rats and may therefore influence atherosclerosis.

Animals↗