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Biomedical subjects

F Pagani

Publications and source records attributed to F Pagani.

At least 73 records · Page 4Linked to original sources
PubMed1995

Nonenzymic glycation of apolipoprotein B in patients with insulin- and noninsulin-dependent diabetes mellitus.

OBJECTIVE: To evaluate the level of nonenzymatic glycation of apolipoprotein B in patients with insulin and noninsulin dependent diabetes mellitus. METHODS: Using a method based on a combination of affinity chromatography and immunonephelometry, we measured the concentration of glycated apolipoprotein B (apo B) in serum of 140 diabetic patients, 43 insulin-dependent (IDDM), and 97 noninsulin-dependent (NIDDM), and 45 nondiabetic control subjects. RESULTS: Although total apo B concentration in serum was significantly increased only in NIDDM patients, both groups of diabetics showed higher percentages of glycated apo B (IDDM, 4.84 +/- 0.8%; NIDDM, 5.61 +/- 1.1%) than did control subjects (4.28 +/- 1.0%), the greatest percentage (5.80%) being found in patients with diabetic nephropathy. No significant correlations were found between glycated apo B and the traditional parameters of glycemic control, such as glycated hemoglobin and fructosamines, and direct influence by sudden plasma glucose fluctuations on apo B glycation was not shown either, perhaps for a low inherent glycability of this apolipoprotein. CONCLUSIONS: It is unclear if these low proportions of glycated apo B in vivo may significantly affect lipoprotein metabolism assuming a pathophysiological role in atherogenesis.

Adolescent↗
PubMed1995

Inhibitory effect of amylin on growth hormone responsiveness to growth-hormone-releasing hormone in the rat.

The effects of intracerebroventricular (i.c.v.) or intracarotid (i.a.) administration of amylin (AMY) on growth hormone (GH) release induced by GH-releasing hormone (GHRH) were examined in conscious male rats. Amylin (25 ng-5 micrograms/rat, i.c.v. or 10 micrograms/rat, i.a.) was administered 10 min before GHRH (2 micrograms/kg, i.a.). I.c.v. administration of AMY dose-dependently inhibited GH secretion induced by GHRH but when given peripherally, AMY did not modify the GH response to GHRH. Amylin (10(-8)-10(-6) M) had no direct effect on the rat anterior pituitary in vitro either alone or when incubated with GHRH. To characterize the mechanism(s) involved in vivo in the inhibition of GH by AMY, we examined, at first, the effects of AMY on GHRH-induced GH release in rats depleted of somatostatin by pretreatment (4 h before) with cysteamine (300 mg/kg s.c.). The inhibitory activity of AMY on GH secretion elicited by GHRH seems to be independent of hypothalamic somatostatin; in fact, AMY was still active in rats treated with cysteamine. In addition, we examined the effects of i.c.v. AMY administration on clonidine (CLO)-induced GH secretion and on dopamine and noradrenaline content in the brain, since it is known that GHRH is a stimulus sensitive to changes in central catecholaminergic activity. The failure of AMY to affect GH secretion induced by activation of postsynaptic alpha 2-receptors by CLO and the finding that the peptide decreased noradrenaline content in the hypothalamus and striatum, indicates that AMY may inhibit GH release by interfering with the facilitatory influence of the catecholaminergic system on GH secretion.

Amyloid↗
PubMed1995

Biological variation in bone-derived biochemical markers in serum.

Analytical, within-subject and between-subject components of variation have been determined for total alkaline phosphatase (ALP) and its bone isoform, osteocalcin, and tartrate-resistant acid phosphatase (TR-ACP) in serum specimens from a cohort of 10 healthy subjects over a 1-month period. From these data, we have calculated the desirable analytical imprecisions, the indices of individuality, the critical differences for significant change detection, and the number of specimens required to estimate the homeostatic setpoint of an individual. For total ALP and its bone isoform, most of the observed variability was biologic, whereas osteocalcin and TR-ACP also had relatively high analytical variability. Total and bone ALP were also the parameters showing the lowest within-subject variability, whereas TR-ACP showed the lowest interindividual fluctuation. Osteocalcin and bone ALP had marked individuality, showing that the use of population-based reference limits is inadequate for their interpretation. The applicable differences required for two results to be significantly different (p < or = 0.05) are bone ALP: 20%; osteocalcin: 29%; and TR-ACP: 35%. The results demonstrate that the biochemical markers of bone turnover studied are of limited use to screen for metabolic bone disorders, but can be useful adjuncts for monitoring groups of patients in longitudinal studies.

Acid Phosphatase↗
PubMed1994

Differential effects of CGRP on adenylyl cyclase in adult and embryonic rat brain.

The presence of functional receptors for calcitonin gene-related peptide (CGRP) in the brain of adult rats and on nerve cell cultures was investigated. Neuronal and glial cultures were obtained from mesencephalons of embryos at gestational day 16. The response to CGRP was tested by measuring the adenylyl cyclase (AC) activity on isolated membranes. CGRP binding in adult rat brains was ineffective in activating AC, whereas a dose-dependent stimulation of AC activity was induced by the peptide both in neuronal and glial cultures. This effect was more pronounced in the glial cells where high affinity binding sites for CGRP were detected. The presence of functional CGRP receptors in embryonic mesencephalic cells, suggests a role for CGRP in the development of rat mesencephalon.

Adenylyl Cyclases↗
PubMed1994

Modulators of oxidized LDL-induced hyperadhesiveness in human endothelial cells.

The adherence of monocytes to the endothelium is an early event in atherogenesis. Our previous studies have demonstrated that oxidized LDL induced U937 cells-endothelial interactions and that HDL prevented oxidized LDL effects. Here, we provide evidence that treatment of endothelial cells with the anti-inflammatory agent indomethacin abolished oxidized LDL as well as interleukin 1- and lipopolysaccharide-stimulated U937 adhesion. It is noteworthy that HDL, which is known to be protective against atherosclerosis, was effective only in negating U937 adhesion induced by oxidized LDL, while it did not affect interleukin 1- and lipopolysaccharide-induced hyperadhesiveness in endothelial cells. Since indomethacin inhibits cyclooxygenase which is the key enzyme in the synthesis of prostanoids, we have studied the effect of oxidized LDL on the expression of cyclooxygenase type 2 and demonstrated that oxidized LDL induces a sustained increase in the expression of cyclooxygenase mRNA.

Cell Adhesion↗
PubMed1994

The protective role of high-density lipoprotein on oxidized-low-density-lipoprotein-induced U937/endothelial cell interactions.

The adherence of monocytes to the endothelium is an early event in atherogenesis. We have investigated this process by examining whether native and oxidized low-density and high-density lipoproteins could modulate this process. Only oxidized low-density lipoprotein caused a significant dose-dependent and time-dependent increase in U937 monocyte-like cell line binding to human endothelial cells, by a process which required de novo protein synthesis. Interestingly, E-selectin, intercellular adhesion molecule-1, vascular cell-adhesion molecule or P-selectin induction was not apparent in this system suggesting the presence of an alternative system for the interaction of endothelial cells with monocyte-like cells in response to oxidized low-density lipoprotein. High-density lipoprotein completely suppressed oxidized low-density-lipoprotein-induced adhesion of U937 cells to the endothelial monolayer, while oxidized high-density lipoprotein did not. These data suggest that the balance between native and oxidized lipoproteins may play a role in the formation of the atherosclerotic lesion by modulating monocyte endothelial interactions.

Base Sequence↗
PubMed1994

Amylin given by central and peripheral routes inhibits acid gastric secretion.

The effect of rat amylin on acid gastric secretion in the pylorus-ligated, unanesthetized rat system (Shay test) was examined. Amylin administered peripherally (2.5, 5, 10, 40, 100, or 160 micrograms/kg, SC) or intracerebroventricularly (1.5, 2.7, or 5 micrograms/rat, ICV) decreased acid gastric secretion in a dose-dependent manner. Central administration of amylin gave a stronger suppression of gastric secretion than peripheral injection. In addition, ICV-injected amylin inhibited insulin-stimulated acid gastric secretion and was effective in suppressing acid gastric secretion in rats depleted of somatostatin by pretreatment with cysteamine. This study suggests that amylin may participate in the central regulation of acid gastric secretion and indicates a possible biological function of amylin as a gastrointestinal peptide.

Amyloid↗
PubMed1994

A histidine to tyrosine replacement in lysosomal acid lipase causes cholesteryl ester storage disease.

The genetic defect causing cholesteryl ester storage disease (CESD) has been investigated in an 11 year old patient. Lysosomal acid lipase (LAL) activity in cultured skin fibroblasts and peripheral lymphocytes was reduced to approximately 3% and approximately 4% of controls, respectively. The parents had low acid lipase activity in white blood cells. Using the polymerase chain reaction followed by ribonuclease protection assay, we examined the LAL mRNA from the liver of the affected patient to identify small deletion, abnormal splicing or missense mutation. Using this technique we identified a LAL mRNA cytosine to thymidine transition in position 923, predicting a missense substitution of tyrosine for histidine in codon 274. By differential oligonucleotide hybridization on an amplified white blood cell mRNA, the cytosine to thymidine transition was investigated in the family members and in the population. No normal mRNA coding for cytosine in position 923 was detectable in the propositus and mRNA from the phenotypically normal parents coded for both cytosine and thymidine. This can only be accounted for by assuming that the propositus is homozygote for the mutation. The mutation, segregated in the family with levels of acid lipase activity in white blood cells, was not detected in mRNA from 60 normal subjects. These data provide evidence that the cytosine to thymidine transition in position 923 in LAL mRNA causes the clinical expression of CESD in this patient. The predicted substitution of tyrosine for histidine in codon 274 suggests that this amino acid is involved in the structure-function of the lysosomal acid lipase enzyme.

Adolescent↗
PubMed1994

Determination of glycated apolipoprotein B in serum by a combination of affinity chromatography and immunonephelometry.

We have developed and optimized a procedure for the quantitation of non-enzymatically glycated apolipoprotein B (apo B). Glycated and non-glycated apo B were separated from serum using m-aminophenylboronate affinity chromatography, determined by immunophelometry and the percentage of glycated apo B was calculated. The measuring range of the assay was 2.9-185 mg/dL apo B. The within- and between-run coefficients of variation were < 7.4% and 14.6%, respectively, and recovery was > 98%. Free glucose in serum did not affect the results at concentrations below 25 mmol/L. In 45 non-diabetic subjects the mean concentration of glycated apo B was 4.3% (SD 1%). In type 1 (n = 17) and Type 2 (n = 60) diabetic patients the mean glycated apo B concentrations were 5.3% (SD 0.7%) and 5.9% (SD 1.1%), respectively, significantly higher than in controls (P < 0.001).

Adult↗
PubMed1994

An immunoinhibition assay for determination of creatine kinase isoforms in serum.

We report a preliminary evaluation of an immunoinhibition assay for creatine kinase isoform quantification. The procedure employs the monoclonal antibody CKM-G01, which inhibits the native M subunit of creatine kinase. The antibody does not inhibit the M subunit modified by removal of lysine by plasma carboxypeptidase N. Residual activity after treatment with the antibody is therefore due to serum delysinated isoforms. The ratio inhibited/residual activity correlated directly with the ratio tissue/serum isoforms. Analysis of the total imprecision of isoform ratio measurement gave a coefficient of variation between 5.9 and 21.1%. Reference intervals for the ratio were 0.14-0.79 in females and 0.19-0.95 in men (p = 0.0046). Analytical and clinical comparison with alternative isoform procedures gave good results, showing that this assay can be used as alternative to the widely accepted electrophoretic method for measurement of the creatine kinase isoform ratio.

Adult↗
PubMed1993

Expression and alternative splicing of fibronectin mRNA in human diploid endothelial cells during aging in vitro.

Different mRNAs for fibronectin arise from the variable processing of a single primary transcript. We used ribonuclease protection assay to investigate the changes occurring in fibronectin expression and the alternative splicing of mRNA precursor during aging in vitro of human diploid endothelial cells. Senescent endothelial cells release more protein and contain 4-5-fold more fibronectin mRNA than young cells. The pattern of alternative splicing of fibronectin mRNA, with the EDA and the CS1 segments largely included (35% and 77%, respectively) and the EDB segment undetectable, correlates well with previous studies at the protein level both in vitro and in vivo. No changes in the splicing pattern of fibronectin mRNA precursor were detected during endothelial cellular senescence. The increased expression of fibronectin in senescent cells may be a result of the activity of interleukin-1 alpha, which is overexpressed in senescent endothelial cells. It could be also important in vivo during aging and in atherosclerotic lesions.

Alternative Splicing↗
PubMed1993

Significance of various parameters derived from biological variability for lipid and lipoprotein analyses.

Analytical, within-subject, and between-subject components of variability have been determined for total cholesterol, LDL-cholesterol, HDL-cholesterol, and its HDL2 and HDL3 subfractions, triglycerides, apolipoproteins A-I and B, and lipoprotein(a) in serum specimens from a cohort of 10 healthy subjects over a 1-month period. From these data, we have calculated the desirable analytical imprecisions, the indices of individuality, the critical differences for significant change detection, and the number of specimens required to estimate the homeostatic set-point of an individual. Practically, the analytical goal for imprecision was not achieved for HDL2 subfraction, lipoprotein(a), and direct LDL-cholesterol determination (obtained vs. theoretical analytical CV, 8.2% vs. 5.9%, 7.4% vs. 3.8%, and 3.2% vs. 2.6%, respectively). All analytes had marked individuality, showing that the use of population-based reference values is inadequate for their interpretation. The applicable differences required for two results to be significantly different (p < or = 0.05) are total cholesterol: 10%; triglycerides: 49%; LDL-cholesterol: 16%; HDL-cholesterol: 14%; HDL2-cholesterol: 40%; HDL3-cholesterol: 16%; apolipoprotein A-I: 11%; apolipoprotein B: 12%; and lipoprotein(a): 29%. Furthermore, it should be clear that population screening for the assessment of risk of coronary artery disease by means of some of the assays studied would result in a significant number of patients requiring analysis of multiple specimens.

Adult↗
PubMed1993

Surgical treatment of Wolff-Parkinson-White syndrome: epicardial approach without the use of cardiopulmonary bypass.

Epicardial dissection without the use of cardiopulmonary bypass (CPB) was performed in 88 patients (56 males and 32 females, mean age 31.9 years). With intraoperative epicardial mapping, 101 accessory pathways were detected, with multiple pathways in 11 patients. CPB was avoided in all but one patient due to frequent onset of atrial fibrillation with rapid ventricular rate. Surgical ablation was successful in 86 patients (97.6%). Three patients required multiple surgical procedures because of persistence of conduction along a component of the original pathway. All but two patients were discharged without antiarrhythmic medication; these two patients were given quinidine therapy because of atrial fibrillation, but had normal early and late electrophysiological studies. Surgical ablation of Kent bundles by the epicardial approach for the treatment of Wolff-Parkinson-White syndrome can be achieved without the use of CPB. Optimal and steady exposure of the area are mandatory for the procedure, and dissection is eased by avoidance of heparin required for CPB.

Adult↗
PubMed1993

Pre-analytical, analytical and biological sources of variation of lipoprotein(a).

The pre-analytical, analytical and biological sources of variation were estimated for serum lipoprotein(a) concentrations, as measured with a new commercially available procedure. There were no significant differences between the concentrations of lipoprotein(a) measured in EDTA plasma and serum. The analyte is stable in specimens stored for up to two weeks in the refrigerator, or up to three months at-20 degrees C. Fasting is not essential before the lipoprotein(a) determination. Data on analytical (between-run coefficient of variation < 15.7%), within-subject (8.6%) and between-subject variation (85.8%) were used to calculate the analytical goal for imprecision (< 4.3%), the critical difference between serial values from an individual that represents a significant change (36.3%), the number of specimens which should be collected to estimate the homeostatic value for an individual to within +/- 5% (26), and to establish the marked individuality of lipoprotein(a) (index of individuality, 0.1).

Adult↗
PubMed1993

Right atrial isolation associated with atrial septal closure in patients with atrial septal defect and chronic atrial fibrillation.

To restore sinus rhythm in the remaining heart chambers of six adult patients with atrial septal defect and chronic or paroxysmal atrial fibrillation, electrical, right atrial isolation associated with surgical correction of the defect was performed. All but one patient was free from atrial fibrillation without medication 2-25 months after operation. The isolated right atrial appendages showed intrinsic rhythmical activity in five patients and no electrical activity in one. Right atrial isolation is a safe and effective procedure that abolishes atrial fibrillation in patients with arrhythmia after surgical correction of atrial septal defect.

Adult↗