The anti-atherogenic properties of HDL particles

High density lipoproteins (HDLs) are a class of lipoproteins characterized by small diameter and high density. Epidemiological studies have demonstrated that HDL cholesterol levels are inversely and independently related to the incidence of coronary heart disease. The mechanisms involved in HDL protection against atherosclerosis are uncertain, but the beneficial effect of HDLs might be the consequence of its properties. The best known of them is related to the “reverse cholesterol transport”, i.e. the transfer of cholesterol from non-hepatic cells to the liver. Second, HDLs exert anti-inflammatory activity by inhibiting the expression of adhesion molecules by endothelial cells and the subsequent transmigration of monocytes. Third, HDLs have antioxidant activity through the anti-oxidative properties of apoprotein A-I, and the presence of enzymes such as paraoxonase, glutathione-peroxidase, and PAF acetylhydrolase. Fourth, HDLs display an anti-thrombotic effect by inhibiting platelets aggregation, reducing von Willebrand factor levels, and enhancing the activity of activated protein C and S. Fifth, HDLs have a beneficial effect on endothelial function by activating endothelial NO synthase and enhancing NO release. Finally, high HDL-C has been associated with “longevity syndrome” while low HDL-C has been related to the “frailty syndrome”, suggesting a possible role of HDL in the phenomenon of successful aging

Endothelial function and postprandial lipemia

It is widely recognised that post-prandial lipoproteins play a role in the development of atherosclerosis, but the mechanisms underlying this role are unclear. An attractive working hypothesis is that the pathogenetic link is endothelial dysfunction. The available data seem to corroborate this theory and recognise triggering by oxidative stress, but some of the evidence is still contradictory.

I trial clinici sull'uso delle statine nella cardiopatia ischemica

--

Disordini del metabolismo delle lipoproteine

Nel capitolo vengono descritti ed analizzati in dettaglio: il metabolismo delle lipoproteine, la classificazione delle dislipidemie, le iperlipoproteinemie primarie e secondarie e il loro trattamento dietetico e farmacologico, le ipolipoproteinemi

Low-dose simvastatin treatment in patients with moderate-grade familial hypercholesterolemia

The efficacy and tolerability of low doses of simvastatin (10 mg daily) were evaluated in a double-blind study conducted in 12 patients with moderate-grade familial hypercholesterolemia (baseline range of cholesterol levels, 240-290 mg/dl). Eight randomly selected subjects were administered active drug for eight consecutive weeks, and the other four were given placebo. At the end of treatment, the simvastatin-treated group showed a significant (P<0.001) decrease in total cholesterol (-26%), low-density-lipoprotein cholesterol (-35%), total cholesterol/high density lipoprotein cholesterol ratio (-25%), and apolipoprotein B levels (-31%). Significant changes in other lipid parameters were not observed, nor were adverse reactions or alterations in safety parameters recorded. In the placebo group, no changes were registered in any of the parameters. Simvastatin, at 10 mg daily, is able to almost normalize cholesterol levels in patients with light- to moderate-grade familial hypercholesterolemia, and considerably attenuate their atherogenic risk

Approccio cronobiologico alla colica renale

The concentration of lithogenic and antilithogenic substances in urine shows circadian fluctuations. With this investigation we intended to verify the presence of a chronobiologic rhythm of colic pain in urinary tract calculosis. Four hundred and forty seven consecutive patients with a clinical symptomatology related to urinary tract colic pain were studied. They were subdivided according to sex and age (297 M, 150 F; > or = 65 ys 29, < 65 ys 428). Urinary and blood chemical analysis and instrumental examinations permitted to confirm the clinical diagnosis. To evaluate the circadian and circannual variability, acute events were grouped into one calendar year by the month and into a ideal day by the hour of occurrence respectively. Chronobiologic analysis was performed utilising Halberg single cosinor test. The results pointed out that the symptomatology related to urinary tract colic pain presents a circadian rhythmicity either in patients as a whole or in single subgroups (males, females, younger or older than 65 ys). Besides no seasonal variability was demonstrated, perhaps because of the mild climate present in the geographic area in which the study was carried on

Lipid abnormalities in patients with extracoronary arteriosclerosis

--

Chronobiological analysis of sudden death observed in an emergency department.

The objective of this study was to evaluate the epidemiological characteristics of sudden death (S.D.), with particular reference to the presence of chronobiological rhythms. One hundred eighty-five fatal events were observed during one solar year at the Emergency Department of a northern Italian town. Twenty-three cases were due to accidents or violence, while the remaining 162 corresponded to the operative definition of S.D. we adopted. Investigation by autopsy permitted to recognize that 36% of total deaths were due to cardiovascular diseases (in 2/3 of the cases secondary to ischemic heart diseases). A significant circadian periodicity was observed in S.D. (p=0.01, with two peaks, at 9.26 a.m. and 9.26 p.m.) and also a circannual rhythm, peaking in late autumn-early winter (p=0.036). The latter was particularly evident in elderly people. A relationship with cardiovascular event rate (of which S.D. recalls the circadian periodicity) is a plausible explanation, while the frequent occurrence of respiratory distress during winter may be at least partly responsible for the high incidence of unexpected deaths seen in this period of the year