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Biomedical subjects

M R Averna

Publications and source records attributed to M R Averna.

At least 37 records · Page 2Linked to original sources
PubMed1998

Lipoprotein profile and high-density lipoproteins: subfractions distribution in centenarians.

In order to assess the role of HDL on longevity, we studied HDL subfraction distribution in centenarian women compared with a group of weight- and gender-matched healthy normolipidemic controls. We did not find any significant difference in the mean plasma lipid, apolipoprotein, and Lp(a) levels. On the contrary, in spite of similar HDL-cholesterol concentrations (1.32 +/- 0.41 mmol/l in centenarians vs. 1.32 +/- 0.25 mmol/l in controls, p = not significant), HDL2b and HDL3a levels were, respectively, significantly increased and significantly reduced in centenarians in comparison with controls (HDL2b 32.4 +/- 9.2% in centenarians vs. 23.4 +/- 7.7% in controls, p < 0.002, and HDL3a 26.3 +/- 9.8% in centenarians vs. 34.1 +/- 7.3% in controls, p < 0.01). Moreover, HDL2b levels were significantly raised and HDL3a levels were significantly reduced in centenarians in comparison with both 'middle-aged' and 'elderly' subjects, whereas no difference for any HDL subfraction was found between the two groups of controls of different ages. Age was significantly correlated with HDL2b and HDL3a (respectively, +0.452, p < 0.001, and -0.370, p < 0.01) in all subjects, but not with all the other lipid, lipoprotein and apolipoprotein parameters, but we observed a large overlapping of individual values of HDL2b between centenarians and controls. Since HDL2b levels were found to be inversely correlated with coronary heart disease risk, we could speculate that, in some cases, this may probably favor a healthy ageing, but long-term longitudinal studies are necessary to define the relative importance of HDL subfractions distribution as a marker of longevity. Probably other factors or clinical characteristics play a major role in the ageing process.

Aged↗
PubMed1996

HDL subfractions distribution in renal transplant recipients: lack of evidence of a reduction of HDL2 particles.

Since the high rate of cardiovascular disease in renal transplant recipients, alterations of lipoprotein profile in such patients were extensively evaluated, but the HDL subclass profile was not completely clarified. Renal transplant recipients usually show normal to high plasma levels of HDL cholesterol, even if some investigations suggested a persistence of low HDL2 levels: this was not useful in terms of cardiovascular protection. We designed this study in order to evaluate HDL subfractions distribution in renal transplant recipients. We studied 55 renal transplant recipients, treated with prednisone, azathioprine and/or cyclosporine, and 34 healthy normolipidemics as controls. In all subjects cholesterol, triglycerides, LDL cholesterol, HDL cholesterol, apolipoproteins A-I and B levels and HDL subfractions, as determined by nondenaturing polyacrylamide gradient gel electrophoresis, were assayed. Renal transplant recipients had cholesterol, triglycerides, LDL cholesterol and apolipoproteins A-I and B levels significantly higher than controls; HDL cholesterol levels were slightly, but not significantly, increased in comparison with controls (respectively 51.1 +/- 15.5 and 46.1 +/- 10.8 mg/dl). Multivariate analysis showed that only the time since transplantation was significantly associated with HDL cholesterol levels. When HDL subfractions were analyzed, renal transplant recipients presented significantly lower levels of HDL3a and HDL3b and, in males, higher levels of HDL2b than controls. HDL cholesterol levels were positively correlated with HDL2b levels in both renal transplant recipients and controls, and negatively correlated with HDL3b in controls. In conclusion, in renal transplant recipients, we failed to demonstrate any decrease of HDL2 particles. On the basis of a nonatherogenic HDL profile, we suggest that the increased cardiovascular risk in renal transplant recipients might be accounted for by other risk factors.

Adult↗
PubMed1995

Effectiveness of cascade filtration plasmapheresis in two patients affected by familial hypercholesterolemia.

Hypercholesterolemia has been recognised as a primary risk factor for coronary heart disease. Reduction of plasma levels of total and LDL cholesterol has been shown to decrease coronary atherosclerosis. Plasmapheresis represents an useful non-pharmacological tool to treat severe hypercholesterolemias. We have evaluated the effectiveness of a system of plasmapheresis using a cascade filtration method in two young male subjects (aged 16 and 26 years) with homozygous familial hypercholesterolemia. Both showed severe coronary atherosclerosis as determined by angiography. Procedures were performed at intervals of 7 days in each case. We observed a mean reduction of plasma levels of total cholesterol of 59.5% (range 31.0-75.5%); LDL-cholesterol, 61.6% (range 32.6-77.1%); triglycerides, 48.1%; HDL-cholesterol, 31.1%; apo A-I, 30.8%; and apo B, 57.6%. We also noted a reduction of other parameters, such as fibrinogen (49.9%) and Lp(a) (59.9%). At the end of each procedure about 8 g of cholesterol was removed from the total body pool. A decrease of total proteins (26.9%) and albumin (19.6%) was also observed, but this was completely restored before the next apheresis (1 week). These data show the effectiveness of the removal of LDL in a cascade filtration system, which obtains results not very different from other more selective methods. The lack of selectivity is not much of a problem, since it also reduces other risk factors such as Lp(a) and fibrinogen.

Adolescent↗
PubMed1995

Plasma levels of lipoproteins and apolipoproteins in congenital hypothyroidism: effects of L-thyroxine substitution therapy.

Thyroid status in humans is an important factor in the regulation of lipoprotein metabolism. There are several data on hypothyroidism in the adult population, but less information is available about congenital hypothyroidism. Since lipid metabolism at birth is substantially different from that of adults, it is not likely that the same abnormalities that occur in adult hypothyroidism are also present when this is diagnosed at early life. We studied 16 subjects with congenital hypothyroidism, seven at the time of diagnosis and also after normalization of thyroid hormone levels over a period of 2.0 +/- 1.0 months of substitution therapy with L-thyroxine (5.9 +/- 1.2 micrograms/kg/d) and nine already on L-thyroxine therapy for a period of 4.7 +/- 3.2 months. Thirty-nine apparently healthy subjects matched for age were selected as controls. In all subjects, total cholesterol (CHO), triglycerides (TG), low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol (HDL-C), apolipoproteins (apo) A-I and B, lipoprotein(a) [Lp(a)] thyrotropin (TSH), (LDL-C), total and free thyroxine (T4), and triiodothyronine (T3) were determined. CHO, HDL-C, and apo A-I levels were significantly higher in patients at the time of diagnosis than in controls (respectively, P = .0079, .0007, and .0004), whereas TG, LDL-C, apo B, and Lp(a) levels were not significantly different. During L-thyroxine substitution therapy in these subjects, HDL-C and apo A-I levels significantly decreased (respectively, by a mean of -36.2% and -24.4%), with similar behavior in all subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Apolipoprotein A-I↗
PubMed1995

Plasma lipid, apolipoprotein and Lp(a) levels in elderly normolipidemic women: relationships with coronary heart disease and longevity.

The relation between plasma lipids and coronary heart disease (CHD) in the elderly is still debated, as well as the proposed role of lipoproteins as markers of longevity. In this study both normolipidemic elderly and middle-aged women with CHD showed higher triglycerides and apolipoprotein B levels and lower high-density lipoprotein (HDL)-cholesterol and apolipoprotein A-I levels in comparison with age-matched subjects without CHD. In the middle-aged group, hypertension and HDL-cholesterol levels and, in the elderly group, only HDL-cholesterol levels were independently associated with CHD. No significant difference was found between a group of healthy centenarians and elderly and middle-aged subjects without CHD. These data suggest that plasma lipids are also related to CHD in the elderly and that, even if at present we are not able to consider them as predictors of longevity, some lipoprotein features may contribute to select subgroups of subjects in which other factors play a further role in life expectancy.

Age Distribution↗
PubMed1994

A new case of apo C-II deficiency with a nonsense mutation in the apo C-II gene.

The apo C-II gene from a patient with apo C-II deficiency has been sequenced after amplification by the polymerase chain reaction (PCR). The sequence analysis revealed a substitution of adenosine for cytosine at position 3,002 in exon 3, leading to the introduction of a premature stop codon (TAA) at a position corresponding to aminoacid 37 of mature apo C-II. This mutation creates a new Rsa I restriction enzyme site in the apo C-II gene. Amplification of DNA from family members by PCR and digestion with Rsa I established that the patient is a true homozygote for this mutation. The same nucleotide has been substituted for the mutation apo C-IIPadova and apo C-IIBari previously described in two kindreds from Italy. From these data we speculate that base pair 3,002 in the apo C-II gene may represent a hot spot for mutation.

Apolipoprotein C-II↗
PubMed1994

Dysbetalipoproteinemia in a kindred with hypobetalipoproteinemia due to mutations in the genes for ApoB (ApoB-70.5) and ApoE (ApoE2).

We identified the first insertion mutation that specifies an apolipoprotein (apo)B truncation, apoB-70.5, in a father and son with hypobetalipoproteinemia (total and low-density lipoprotein [LDL] cholesterol < 5th percentile, plasma apoB levels approximately one third of normal). The mutation is due to insertion of an adenine (A) into a 7-A repeat between cDNA position 9754 and 9760 of the apoB gene, resulting in a frame shift of 13 new amino acids and a termination codon at amino acid residue 3197. The DNA mutation cosegregated with the apoB truncation and hypobetalipoproteinemia in the kindred. The two apoB-70.5/apoB-100 heterozygotes also are apoE2 homozygotes by genotyping; beta-very-low-density lipoprotein (VLDL) was present, and VLDL cholesterol/triglyceride ratios were increased (0.29) in the plasmas of both. Density gradient ultracentrifugation and gel filtration chromatography profiles showed increased amounts of particles in the VLDL and intermediate-density lipoprotein density and size ranges and relatively smaller peaks of LDL than in controls. Two populations of LDL were present, ApoB-70.5 was primarily associated with LDL particles of higher density and of smaller size than the LDL particles containing apoB-100. ApoB-48-containing particles were present in the VLDL of fasting plasmas of both subjects, and the postprandial levels of chylomicrons and remnants as measured by the vitamin A fat tolerance test were increased. In conclusion, both subjects heterozygous for apoB-70.5 and homozygous for apoE2 showed the classic characteristics of dysbetalipoproteinemia superimposed onto the hypolipoproteinemia state.

Adult↗
PubMed1994

Apo-lipoprotein profile in subjects with extracranial carotid atherosclerosis.

Relationships between plasma lipoproteins and cerebrovascular atherosclerosis are not completely clear. In a group of asymptomatic nondiabetic normolipidemic subjects, plasma lipid and apolipoprotein profiles have been related to extracranial carotid atherosclerotic lesions, as assessed by B-mode ultrasonography and independent relations between lipid and clinical parameters and carotid atherosclerosis have been evaluated. We have found that subjects with atherosclerotic lesions (both intimal thickening or plaque) had TG levels and CHO/HDL-C and LDL-C/HDL-C ratios significantly higher and HDL-C and apo A-I levels significantly lower in comparison with subjects with normal arteries. When patients were divided according to the lesions of carotid arteries subjects with atherosclerotic plaque presented HDL-C and apo A-I levels significantly reduced and TG and apo B levels and CHO/HDL-C and LDL-C/HDL-C ratios significantly increased in comparison with subjects with normal arteries, and HDL-C levels reduced and CHO/HDL-C and LDL-C/HDL-C ratios increased in comparison with subjects with intimal thickening. Patients with intimal thickening and normal subjects differed for HDL-C and TG levels and CHO/HDL-C and LDL-C/HDL-C ratios. At multivariate analysis HDL-C levels (negatively), age, hypertension and cigarette smoking (positively) resulted independently associated with cerebrovascular atherosclerosis. Our data seem to show that, although several lipid and apoprotein abnormalities are able to initiate the atherosclerotic process in extracranial carotid district, probably the presence of low HDL-cholesterol levels is an important condition to determine the further worsening of the lesions.

Adult↗
PubMed1994

Apolipoprotein B-38.9 does not associate with apo[a] and forms two distinct HDL density particle populations that are larger than HDL.

We have identified a new truncated apolipoprotein B (apoB) that provides insights into the interaction of apoB with apo[a] and with lipids. Both total and LDL-cholesterol were below the 5th percentile in the proband; Lp[a] was 28 mg/dl. Four other affected individuals were identified in this kindred. Immunoblotting of plasma apoB-containing lipoproteins with an anti-apoB monoclonal antibody revealed a major band for apoB-100 and a minor band with apparent M(r) 217 kDa. The apoB truncation is due to a -1 frameshift mutation, consisting of a cytosine deletion at cDNA position 5444, that results in the translation of 22 novel amino acids terminating at residue 1767. The mutation was confirmed in the affected subjects by allele-specific oligonucleotide (ASO) analysis. Gel filtration of whole plasma revealed that the minority of apoB-38.9 eluted with IDL- and LDL-sized particles, while the majority (approximately 60%) eluted between LDL and HDL. Lp[a] eluted between VLDL and LDL. Upon preparative density gradient ultracentrifugation (DGUC), the majority of the plasma apoB-38.9 (approximately 65%) floated at a density of 1.12 g/ml coincident with the major peak of HDL cholesterol. Lp[a] floated at a peak density of 1.08 g/ml between LDL and HDL. Immunoblots of the apoB-38.9-containing HDL density DGUC fractions subjected to nondenaturing gradient gel electrophoresis (GGE) demonstrated two apoB-38.9-containing particle populations with diameters of approximately 15 nm and approximately 18 nm, respectively. Lipoproteins of these sizes were also detected when whole plasma was subjected to GGE and immunoblotting. The 15-18 nm lipoproteins correspond to the gel filtration populations eluting between LDL and HDL. Lysine-Sepharose chromatography of plasma yielded retained products that contained apo[a] and apoB-100 but not apoB-38.9. Immunoprecipitation of whole plasma with monospecific polyclonal anti-human apo[a] showed apo[a] and apoB-100, but no apoB-38.9 to be present in precipitates. ApoB-100 and apoB-38.9 were present in supernates. In in vitro incubations, recombinant apo[a] formed complexes with apoB-100 but not with apoB-38.9-containing particles. Our results show that the apoB-38.9 protein can be found in a variety of lipoproteins; however, the majority of apoB-38.9-containing lipoproteins float at a density equivalent to HDL but are larger than HDL, being intermediate in size between apoB-100 LDL and HDL. The heterogeneity of apoB-38.9 lipoproteins may reflect their dual tissue source, i.e., liver and intestine, and the discordance between size and density indicates a disproportionately reduced association of lipids with apoB-38.9. Finally, our data suggest that apoB-38.9 is incapable of forming complexes with apo[a] in plasma.

Aged↗
PubMed1993

Transient neonatal hypercholesterolemia. Lack of relationships with dehydroepiandrosterone sulfate.

In order to obtain new information about the relationship between transient neonatal hypercholesterolemia and adrenal gland function, we have studied 39 healthy babies found hypercholesterolemic at birth and 39 healthy controls with normal cholesterol levels. The results of this study have shown that levels of dehydroepiandrosterone sulfate in cord blood were not significantly different in the hypercholesterolemic subjects compared with normolipidemic controls (1.4 +/- 0.5 micrograms/dl vs 1.3 +/- 0.5 mu/dl). Moreover correlations between this hormone and levels of total and LDL-cholesterol were not only not statistically significant but even positive (respectively r = +0.207 and +0.195). These data suggest that dehydroepiandrosterone sulfate measurements in cord blood do not give any further information about transient neonatal hypercholesterolemia.

Adrenal Glands↗
PubMed1993

Lipoprotein (a) levels in end-stage renal failure and renal transplantation.

Some previous studies have documented an increase in lipoprotein (a) [Lp(a)] levels in renal diseases. Here, we report data in subjects with end-stage renal failure treated with hemodialysis (HD) or with continuous ambulatory peritoneal dialysis (CAPD) and in renal transplant recipients (RTR), compared with a group of normolipidemic controls (C). Lp(a) levels were significantly increased in HD and CAPD patients in comparison with C, while they were only slightly increased in RTR. Both HD and CAPD patients showed Lp(a) levels higher than in RTR, but no difference was found between the subjects of the two dialysis procedures. The prevalence of Lp(a) levels > 25 mg/dl was significantly higher in HD and CAPD patients, but not in RTR, in comparison with C. Moreover, Lp(a) levels did not change after HD. When patients were divided according to their fasting lipid levels in normolipidemics and hyperlipoproteinemics, no difference was found for Lp(a) levels in any group. Mechanisms underlying the increase in Lp(a) levels in these patients are not known. It is possible to suggest an active role of the kidney in the Lp(a) metabolism or that uremic plasma contains some factors affecting Lp(a) metabolism.

Adult↗
PubMed1992

Use of famotidine in severe exocrine pancreatic insufficiency with persistent maldigestion on enzymatic replacement therapy. A long-term study in cystic fibrosis.

In patients with pancreatic exocrine insufficiency, the use of pancreatic enzyme does not abolish steatorrhea in some cases. We carried out a long-term prospective study in an attempt to clarify the effectiveness of the associated use of famotidine to enzymatic supplementation on fat absorption and nutritional parameters of patients with pancreatic insufficiency due to cystic fibrosis. We studied 10 patients, mean age 12.5 years, with persistent steatorrhea on enzymatic supplementation. A double-blind crossover design was used and famotidine (1 mg/kg/day) or placebo was given as adjuvant to enzymatic preparations for either of two six-month periods. A statistically significative reduction in fecal wet weight (P less than 0.0001), an improvement in the coefficient of fat absorption (P less than 0.01) and in the steatocrit values (P less than 0.028) were found on famotidine. Moreover, the weight and the height increases were greater after famotidine than after placebo period (respectively, P less than 0.012 and P less than 0.01); also the serum calcium and triglycerides levels were higher after the period on famotidine (respectively, P less than 0.0025 and P less than 0.025). No adverse effects of famotidine were noted. These data suggest that famotidine is a useful adjuvant to pancreatic enzyme therapy in patients with severe pancreatic insufficiency and persistent maldigestion on large doses of pancreatic supplements; in fact, famotidine improves not only fat absorption but the nutritional status of the patients.

Adolescent↗
PubMed1992

Prevalence of biliary lithiasis in the elderly people of a small town in Sicily.

The aim of the present study was to determine the prevalence of biliary lithiasis (BL) and its major associated factors in the elderly people of a small town in Sicily. All inhabitants over the age of 65 were interviewed and underwent a general physical examination, blood tests and ultrasonography of the gallbladder and biliary tracts. The final group included 328 subjects (162 men and 166 women), representing 63.1% of the population asked to participate, with a mean age of 74.3 +/- 6.8 years (range 65-95). The prevalence of BL (lithiasis in progress + subjects cholecystectomized for previous calculosis) was 18.6%. No male subject had been cholecystectomized. Prevalence was higher in women than in men, but there was no progressive increase with age. There was no significant correlation between number of pregnancies and BL and there was no statistically significant difference between subjects with and without lithiasis for total cholesterol, triglycerides, HDL-cholesterol, A-I and B apoprotein values; a significant difference was found only for body weight values (p less than 0.01). Stones were more often multiple and more radiopaque than in younger subjects; specific symptoms and positive family histories were found in 22% and 18% of the study group, respectively.

Aged↗
PubMed1992

Lp(a) levels in patients undergoing aorto-coronary bypass surgery.

The aims of this study were to evaluate plasma lipid, apoprotein and Lp(a) levels in patients with severe coronary atherosclerosis undergoing aorto-coronary bypass surgery (BP) and to relate these parameters to the involvement of one or more vessels. Seventy-seven male patients and 77 cardiovascular disease-free controls, matched for sex, age and body weight were studied. Higher triglyceride and apo B levels with lower HDL-cholesterol and apo A-I levels were found in BP patients in comparison with the controls. Lp(a) levels were slightly, but not significantly, increased. Moreover BP patients presented a significantly higher prevalence of HDL-cholesterol levels below 35 mg dl-1 (49.3% vs 22.1%) and Lp(a) levels above 70 mg dl-1 (10.4% vs 1.3%) than the controls. When patients were divided according to the number of coronary vessels involved (one, two or three), no significant difference was found, with a trend to increase in Lp(a) mean levels and in prevalence of Lp(a) levels above 30 and 70 mg dl-1 in more severely diseased patients. These results suggest that patients with severe coronary artery disease undergoing aorto-coronary bypass surgery show low HDL-cholesterol levels with high triglyceride levels. Moreover Lp(a) levels above 70 mg dl-1 are highly associated with severe coronary vessel stenosis.

Aged↗
PubMed1992

[Total cholesterol, LDL-cholesterol and apoprotein B in umbilical cord blood: cross-sectional study].

The aim of the present study was to evaluate, in a large series of term newborns, the prevalence of hypercholesterolemia in cord blood, using as parameters, levels of plasma cholesterol, LDL-cholesterol and apo B higher than mean + 2 standard deviations, alone or in association. Data reported here represent the results of a transversal study. 1275 term newborns were studied. In everybody, in cord blood samples, at birth, cholesterol, triglycerides, HDL-cholesterol, apoprotein B and LDL-cholesterol have been assayed. In 3.13% of them (40 subjects), cholesterol levels > mean + 2 standard deviations were present. Moreover, only 6 subjects (0.47%) showed all three parameter levels higher than mean + 2 standard deviations, and 4 subjects (0.31%), in spite of normal cholesterol levels, presented high LDL-cholesterol and apo B levels. Integrated utilization of these parameters in the neonatal screening of familial hypercholesterolemia will have to be confirmed by follow-up studies.

Apolipoproteins B↗
PubMed1992

[Plasma lipids and apoproteins. The effect of cigarette smoking].

Cigarette smoking produces lipo-apoprotein modifications, which makes it more atherogenic. In this study we have evaluated lipids and apoproteins in 178 normolipidemic, healthy subjects, in relation to their smoking habits. In smokers we have found lower levels of HDL-cholesterol and apo A-I and higher levels of triglyceride and apo B. Number of cigarette smoked in a day directly correlated with triglycerides and apo B (r = 0.321 and 0.313 respectively) and inversely with HDL-cholesterol (r = -0.274). These alterations seem to be due to an inhibition that smoking could cause on lipolytic processes. Further studies need to establish influences that smoking-related alterations have in the atherosclerotic lesions of smokers.

Adult↗