Uric acid does not affect the prevalence and extent of coronary artery disease. Results from a prospective study.

BACKGROUND: Hyperuricemia may be involved in the atherosclerotic process due to endothelial dysfunction and facilitation of smooth muscle cell proliferation. However, debates still exist on the independent role of hyperuricemia, due to its association with several cardiovascular risk factors, such as hypertension, hyperlipidemia, obesity and insulin resistance. Thus, the aim of the current study was to investigate in a consecutive cohort of patients undergoing coronary angiography whether hyperuricemia is associated with the extent of coronary artery disease. METHODS AND RESULTS: Our population is represented by a total of 1901 consecutive patients undergoing coronary angiography between May 2007 and January 2010 at the Azienda Ospedaliera "Maggiore della Carità", Novara, Italy. We additionally evaluated platelet aggregation by PFA-100 (Collagen/Epinefrine) and Multiplate. Quantitative coronary angiography and analysis of IMT were performed by experienced cardiologists who had no knowledge of the patients' clinical information. Higher uric acid was associated with advanced age, larger prevalence of male gender, diabetes, renal insufficiency, hypertension, previous CABG and MI, but with a lower prevalence of family history of CAD. Patients with high uric acid were more often on calcium antagonists, ace-inhibitors, angiotensin receptor antagonists, and, as expected, on diuretics. A significant relationship was observed between uric acid and the prevalence (OR [95% CI] = 1.18 [1.04-1.32], p = 0.01) and severity of CAD (OR [95% CI] = 1.17 [1.03-1.33], p = 0.014). However, the relationship disappeared after correction for baseline confounding factors for both prevalence (OR [95% CI] = 1.06 [0.93-1.21], p = 0.35) and extent of CAD (OR [95% CI] = 1.0 [0.87-1.15], p = 0.96). No relationship was observed between acid uric and IMT (p = 0.73) analyzed in 359 consecutive patients. Finally, there was no relationship between uric acid and platelet aggregation in patients with or without aspirin therapy, as measured by PFA-100 and Multiplate. CONCLUSIONS: Our study showed that uric acid is not associated with platelet aggregation, the extent of coronary artery disease and IMT. Thus, waiting for the results of additional large studies, uric acid may not be considered as a risk factor for coronary artery disease, and its reduction by specific therapies may not be recommended to prevent coronary artery disease and atherosclerosis.

Mitochondrial DNA insertions in the nuclear horse genome.

The insertion of mitochondrial DNA in the nuclear genome generates numts, nuclear sequences of mitochondrial origin. In the horse reference genome, we identified 82 numts and showed that the entire horse mitochondrial DNA is represented as numts without gross bias. Numts were inserted in the horse nuclear genome at random sites and were probably generated during the repair of DNA double-strand breaks. We then analysed 12 numt loci in 20 unrelated horses and found that null alleles, lacking the mitochondrial DNA insertion, were present at six of these loci. At some loci, the null allele is prevalent in the sample analysed, suggesting that, in the horse population, the number of numt loci may be higher than 82 present in the reference genome. Contrary to humans, the insertion polymorphism of numts is extremely frequent in the horse population, supporting the hypothesis that the genome of this species is in a rapidly evolving state.

Telomeric repeats far from the ends: mechanisms of origin and role in evolution.

In addition to their location at terminal positions, telomeric-like repeats are also present at internal sites of the chromosomes (intrachromosomal or interstitial telomeric sequences, ITSs). According to their sequence organization and genomic location, two different kinds of ITSs can be identified: (1) heterochromatic ITSs (het-ITSs), large (up to hundreds of kb) stretches of telomeric-like DNA localized mainly at centromeres, and (2) short ITSs (s-ITSs), short stretches of telomeric hexamers distributed at internal sites of the chromosomes. Het-ITSs have been only described in some vertebrate species and they probably represent the remnants of evolutionary chromosomal rearrangements. On the contrary, s-ITSs are probably present in all mammalian genomes although they have been described in detail only in some completely sequenced genomes. Sequence database analysis revealed the presence of 83, 79, 244 and 250 such s-ITSs in the human, chimpanzee, mouse and rat genomes, respectively. Analysis of the flanking sequences suggested that s-ITSs were inserted during the repair of DNA double-strand breaks that occurred in the course of evolution. An extensive comparative analysis of the s-ITS loci and their orthologous 'empty' loci confirmed this hypothesis and suggested that the repair event involved the direct action of telomerase. Whereas het-ITSs seem to be intrinsically prone to breakage, the instability of s-ITSs is more controversial. This observation is consistent with the hypothesis that s-ITSs are probably not themselves prone to breakage but represent 'scars' of ancient breakage that may have occurred within fragile regions. This study will review the current knowledge on these two types of ITS, their molecular organization, how they arose during evolution, their implications for chromosomal instability and their potential applications as phylogenetic/forensic markers.

17 alpha-O-(aminoalkyl)oxime derivatives of 3 beta,14 beta-dihydroxy-5 beta-androstane and 3 beta-hydroxy-14-oxoseco-D-5 beta-androstane as inhibitors of Na(+),K(+)-ATPase at the digitalis receptor.

The synthesis and binding affinities to the digitalis Na(+),K(+)-ATPase receptor of a series of 3 beta,14 beta-dihydroxy-5 beta-androstane and 3 beta-hydroxy-14-oxoseco-D-5 beta-androstane derivatives bearing a 17 alpha-(aminoalkoxy)imino chain are reported; some derivatives were also studied for their inotropic activity. Our recently proposed model of interaction of molecules with the digitalis receptor was used to design these compounds. On that basis, the possibility to design novel potent inhibitors of Na(+),K(+)-ATPase without being constrained by the stereochemistry of the classical digitalis skeleton in the D-ring region was predicted. The binding affinities of the most potent compounds in the two series, (EZ)-17 alpha-[2-[(2-aminoethoxy)imino]ethyl]-5 beta-androstane-3 beta,14 beta-diol (6f) and (EZ)-3 beta-hydroxy-17 alpha-[2-[(2-aminoethoxy)imino]ethyl]-14,15-seco-5 beta-androstan-14-one (24c) are higher than that of the potent natural compound digitoxigenin, despite the unusual alpha-exit of the substituent in position 17 of 6f or the disruption of the D-ring in 24c. These results further support the validity of our recently proposed model of binding at the digitalis receptor. Results of the inotropic tests on guinea pig atrium deserve further investigation on the pharmacological profile of these derivatives.

New geographical records of parasitic nematodes from Bufo bufo in Italy.

To provide information on parasites of Bufo bufo (toad), eyes, skin, lungs, gut and urinary bladder of individuals collected near lakes Endine and Segrino (Northern Italy) from March to April 1999 were recorded in laboratory. A total of five nematode species were classified: Oswaldocruzia filiformis, Oxysomatium brevicaudatum, Cosmocerca ornata, Neyraplectana schneideri were found in the intestine and rectum and Rhabdias sphaerocephala in the lungs. Of these species, the last three are new geographical records for Italy.

17beta-O-Aminoalkyloximes of 5beta-androstane-3beta,14beta-diol with digitalis-like activity: synthesis, cardiotonic activity, structure-activity relationships, and molecular modeling of the Na(+),K(+)-ATPase receptor.

A series of digitalis-like compounds with a 17-aminoalkoxyiminoalkyl or -alkenyl substituent was synthesized and evaluated for inhibition of Na(+),K(+)-ATPase and for inotropic activity. The highest inhibition was found with compounds having the substituent in configuration 17beta and the amino group at a distance of 6 or 7 bonds from C(17) of the digitoxigenin skeleton. The presence of the oxime function strengthens the interaction with the receptor, more if alpha,beta-unsaturated, thus mimicking the electronic situation of the unsaturated lactone in natural digitalis compounds. The most active compounds showed Na(+),K(+)-ATPase inhibitory potencies (IC(50)) 17-25 times higher than the standards digitoxigenin and digoxin and 3-11 times higher inotropic potencies (EC(50)) in isolated guinea pig left atria. These features are supported by a molecular model suggesting the possible interactions of the groups described above with particular amino acid residues in the H1-H2 domains of Na(+),K(+)-ATPase. Some interactions are the classical ones already described in the literature; a new, very strong interaction of the basic group with the Cys138 was found and adds new possibilities to design compounds interacting with this region of the receptor. The most interesting compounds were also studied in vivo in the anesthetized guinea pig for evaluating their inotropic effect versus the lethal dose. Compounds 9 and 12 showed a slightly higher safety ratio than digoxin and deserve further evaluation.

Evaluation of the reperfusion syndrome after liver ischemia in the rat.

Hepatic surgery in man often requires a transient interruption of the blood flow to the liver. After the vascular declamping the hepatic reperfusion induces a group of phenomena commonly called "reperfusion injuries." The aim of this study was to evaluate the presence and effect of vasoactive agents that could induce the acute pulmonary arterial hypertension which contributes to reperfusion injury. Wistar rats were used. The hepatic ischemia was induced by crossclamping the whole hepatic hilus for 20, 40, and 60 min. In control experiments a sham operation was performed. Blood samples were collected from the suprahepatic inferior vena cava. Strips of the main pulmonary artery were set up in an isolated organ bath and tested for the response to noradrenaline, adrenaline, KCl, and plasma samples. Plasma levels of catecholamines were determined by high-performance liquid chromatography. Plasma concentration of noradrenaline significantly increased from 1.6 +/- 0.4 (control) to 10.8 +/- 2.9 ng.ml-1 and adrenaline concentration rose from 2.7 +/- 0.7 to 38.7 +/- 7.6 ng.ml-1 after ischemia. Noradrenaline potency, compared to control values, significantly increased after prolonged liver ischemia. The plasma samples collected after prolonged liver ischemia caused a greater contraction of the pulmonary artery than from control plasma. This contraction is partially inhibited by phentolamine. We conclude that hepatic ischemia modifies the response of the pulmonary artery to exogenous noradrenaline. At the same time it induces an increase in the plasma levels of adrenaline and noradrenaline. The resulting combined effect may cause the pulmonary hypertension which has been observed in reperfusion injury.

High- and low-flux acetate-free biofiltration: experimental assessment of calcium mass balance and intact parathyroid hormone behaviour.

We studied total calcium mass balance and plasma intact parathyroid hormone behaviour in 10 uraemic patients who underwent acetate-free biofiltration carried out in accordance with six different dialytic schedules, where either a polyacrylonitrile or a polysulphone membrane was used. Schedules 1 and 2 involved a reinfusion flow rate of 33.3 ml/min with a dialysate calcium concentration (DCa) of 1.75 and 2 mmol/l respectively; in schedule 3, 4, 5 and 6 reinfusion flow rate amounted to 50 ml/min and DCa was respectively of 1.75, 2, 2.25 and 2.5 mmol/l. Dehydration remained unchanged in all schedules: 700 g/h. Finally high- and low-flux acetate-free biofiltration are able to induce different Ca mass balance which may suit different therapeutic contexts. Ca mass balance was either positive or negative depending on reinfusion flow rate and DCa. With a reinfusion flow rate of 33.3 ml/min a DCa of at least 2 mmol/l was necessary to obtain a positive mass balance, while with a reinfusion flow rate of 50 ml/min DCa had to equal 2.25 mmol/l. In high-flux acetate-free biofiltration, the estimation of predialytic Ca2+ and DCa values, using a simple formula, allows prediction of the mass balance that will be attained. At the end of acetate-free biofiltration, intact parathyroid hormone always decreased when a polyacrylonitrile membrane was employed while it increased, in the presence of negative Ca mass balance with a polysulphone membrane.

Calcium mass balance and behavior of intact immunoreactive parathyroid hormone in acetate-free biofiltration: acute and one-year evaluation.

The present study evaluated calcium mass balance (MB) during acetate-free biofiltration (AFB) with a dialysate calcium concentration of 2 mmol/l and different ultrafiltration rates (UF; 42.5 ml/min in schedule 1 and 48.5 ml/min in schedule 3), and with a calcium concentration of 1.75 mmol/l but an UF of 43 ml/min (schedule 2). We also examined the effects of these schedules on the behavior of intact parathyroid hormone (I-PTH). AFB according to schedule 1 and 3 achieve a positive calcium MB (8.49 +/- 1.56 and 5.59 +/- 1.06 mmol, respectively), while in schedule 2 calcium MB merely balanced (0.07 +/- 2.29 mmol/l). A significant acute intradialytic I-PTH decrease was observed with all schedules; after 1 month, however, predialytic PTH values were unchanged in schedules 1 and 3, but worsening was noted in schedule 2. Subsequently, AFB was performed for 12 months employing a dialytic schedule (No. 1) involving a positive calcium balance. A year later I-PTH was significantly lower, thus proving that AFB may play an additional part in controlling secondary hyperparathyroidism.

Long-term effect of oral calcitriol single weekly pulse in CAPD and in HD.

This study was undertaken to evaluate the long-term effect of single weekly oral pulse calcitriol therapy (0.05 mcg/kg) in 16 uremic patients. Eight (5 female, 3 male; aged 51.6 +/- 8.5 years) were on continuous ambulatory peritoneal dialysis (CAPD) for 28.8 +/- 12.7 months with basal intact parathyroid hormone (iPTH) 247 +/- 60 pg/mL. Eight (6 female, 2 male; aged 53 +/- 17.9 years) were on hemodialysis (HD) for 76.3 +/- 55 months with basal iPTH 270.9 +/- 92. Calcium dialysate was 1.75 mmol/L in all patients and serum phosphorus was controlled with CaCO3 2-4 g/day. Ca and P were measured weekly; iPTH and alkaline phosphatase were measured monthly. After two months, iPTH decreased to 132.4 +/- 89 (p < 0.05 vs basal values) in the HD patients and to 158.2 +/- 61 (p < 0.05) in the CAPD group. After six months, iPTH decreased to 108.6 +/- 73.2 (p < 0.01) in the HD patients and to 126.5 +/- 48 (p < 0.01) in the CAPD patients. Two patients (1 HD and 1 CAPD) who were not compliant with phosphate binder therapy were dropped. To control hyperphosphatemia in 1 HD patient we reduced bolus to 0.03 mcg/kg. Two CAPD patients presented hypercalcemia and required calcium dialysate of 1.25 mmol/L. In conclusion, single weekly oral pulse of calcitriol appears to be effective in suppressing mild hyperparathyroidism both in CAPD and in HD patients, even though some variations in the protocols may be required.

Acute effects of repetitive hemodialysis on circulating immunoreactive parathyroid hormone levels in uremic patients undergoing vitamin D (calcitriol) therapy.

The acute effects on parathyroid gland activity of repetitive hemodialysis with a dialysate calcium concentration of between 3.5 and 4 mEq/l were evaluated in 21 hemodialysis patients on calcitriol therapy for 1 year or more. In this study circulating immunoreactive parathyroid hormone (iPTH) levels were measured using radioimmunoassay specific for C-terminal iPTH (C-PTH), middle molecule iPTH (MM-PTH) and intact iPTH (I-PTH), before the dialysis session at the end of the week (I), after 4 h regular hemodialysis (II) and after a further 72 h (III). C-PTH was abnormally high (202 +/- 64 pmol/l) (I) in 18 patients with no documented parathyroid hyperplasia and showed no significant difference in subsequent controls. MM-PTH was also high (379 +/- 125.5 pmol/l) (I), but decreased to 348 +/- 136.7 (II) (p less than 0.05) and returned to predialysis levels (III). I-PTH (I) was 8.2 +/- 5.3 pmol/l (normal levels in 8 patients), fell to 3.4 +/- 2.6 pmol/l (II) (p less than 0.01), and increased (p less than 0.01) with respect to the basal levels of 11.1 +/- 7.5 pmol/l (III). Three patients presented echographically documentable parathyroid hyperplasia and, despite constantly high iPTH levels, showed a similar I-PTH behavior while MM-PTH and C-PTH revealed no constant pattern. The decrease in iPTH levels was accompanied by a significant increase in total calcium and ionized calcium during the hemodialysis session. No significant changes in iCa and Ca together with I-PTH levels were found in 4 volunteers before and after the hemodialysis session with dialysate calcium 2.75 mEq/l. We conclude that I-PTH assay has been shown to capture acute changes in parathyroid gland activity in hemodialyzed patients for both low and high iPTH levels. High calcium dialysate hemodialysis inhibits acutely intradialytic PTH secretion but the effect is just temporary and the 72-hour interdialytic period, despite vitamin D therapy, stimulates parathyroid secretion significantly. Nevertheless, I-PTH fluctuations occur in some patients within the normal range, and high dialysate and calcitriol therapy seem to be capable of controlling parathyroid activity; as regards the remaining population, we suggest that a personalized therapeutic approach should be studied with a view to achieving a better control of interdialytic calcium homeostasis.

[Survey on goiter in elementary school children in the Bisagno and Trebbia valleys (Liguro-Emilian Apennines)]. / Inchiesta sul gozzismo in età scolare primaria nelle valli Bisagno e Trebbia (Appennino Ligure-Emiliano).

The authors have made an inquiry about school-children of two villages of Northern Appennines: Bargagli and Ottone, formerly seats of endemic goiter. The disappearance of endemic goiter in the younger generations of these villages, is in accordance with previous observations by one of the writers suggesting that sheep represent an important ecologic factor in endemic areas.