E. Petruzzi

Diabetes mellitus and subjects' ageing: a study on the ATP content and ATP-related enzyme activities in human erythrocytes.

Na+/K+‐ and Ca2+‐ATPase are the major ATP‐dependent membrane‐bound enzymes that regulate the cation transmembrane gradient which is altered both in red blood cell (RBC) senescence and in RBCs of diabetic patients. In an attempt to clarify the possible connection between diabetes mellitus and ageing, we investigated the relationship between RBC ATP content, Na+/K+‐ATPase, Ca2+‐ATPase activities and ageing in healthy, insulin‐dependent (IDDM) and non‐insulin‐dependent (NIDDM) subjects. A significant correlation was found (r = −0.82; P < 0.001) between RBC ATP content and subjects age only in the control group. A significant reduction in Na+/K+‐ATPase activity was observed in the older group (C2) of control subjects, in comparison with the younger (C1) one. In both IDDM and NIDDM subjects, the enzymatic activity was significantly decreased when compared with healthy subjects of similar age (P < 0.001). A significant negative correlation was found between age and enzymatic activity in healthy subjects (r = −0.60; P < 0.001). No difference was observed in the RBC membrane Ca2+‐ATPase activity between younger (C1) and older (C2) healthy subjects. Ca2+‐ATPase activity was significantly increased both in IDDM patients compared with C1 (P < 0.001) and in NIDDM patients compared with C2 (P < 0.001). The present data indicate that ageing causes a reduction in the erythrocyte ATP content in both healthy and diabetic subjects. In diabetic patients Na+/K+‐ATPase activity decreases independently of age.

Centenarians in Tuscany: The role of the environmental factors

Statistical data of Italy, issued on 1st January 2005, show that Tuscany has a high percentage of elderly subjects, and that to reach 100 years is a common possibility, mainly for women. Comparable values appear for longevity index (LI%), either calculated on the basis of the various resorts above sea level, or on the basis of the number of inhabitants. However, some differences are observed considering the various provinces: Grosseto Province has the second higher value of >65-year-old subjects, while its LI% is the lowest. Centenarity index (CI%) considerably differs from LI%: if ranking Tuscany according to the various heights of territorial positions, the first displays a negative, while the second one shows a positive correlation with the local height. If comparing for inhabitants number, CI% is maximal in provincial cities, while LI% is higher in smaller communities. All these data indicate that residents in small communities of the mountains reach easily 90 years, while 100 years are more frequently reached in larger cities in the plane areas. In conclusion, the highest province longevity (Lucca) coincides with the highest centenarian sex ratio, and it suggests that in this province the older women may enjoy particular forms of environmental protection, which helps them for reaching 100 years of age. Differences between the results of this study and others performed in Sardinia are discussed.

Serum antioxidant capacity in healthy and diabetic subjects as determined by enhanced chemiluminescence

Free radicals are considered to be important factors involved in many physiopathological processes. Several methods have been proposed for studying the mechanisms of antioxidant protection against free radical-induced injury, including the measurement of the total antioxidant capacity (TAC) in body fluids, based on enhanced chemiluminescence. This technique is calibrated against Trolox and assay results are expressed as mumol/L of Trolox equivalents. Since many of the complications induced by diabetes appear to be mediated by oxygen free radical generation, we have investigated serum antioxidant capacity in a group of healthy subjects and in insulin-dependent diabetic (IDDM) subjects. A statistically significant difference was noticed in TAC values between the IDDM group and the young control group. Even if the biological meaning of this significant reduction in TAC remains to be explained, an overproduction of precursors of reactive oxygen free radicals and/or a decreased scavenger systems efficiency can be associated with the increased risk of atherosclerotic cardiovascular disease in diabetic patients.

Erythrocyte plasma membranes obtained from centenarians show different functional properties.

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Clinical, biochemical and therapeutical aspects of amiodarone-induced hypothyroidism (AIH) in geriatric patients with cardiac arrhythmias

The clinical features and the laboratory aspects of the amiodarone-induced hypothyroidism (AIH) in the elderly as well as the effects of amiodarone treatment in aged AIH people have not yet been well clarified. In the present paper, we evaluated 18 subjects of both sexes (7 females, 11 males), aged 65-83 years, affected by AIH, recruited in Central Tuscany, Italy. The patients were divided in two subsets on the basis of thyroid stimulating hormone (TSH) values: mild (TSH < 20 mU/l; Group A, n=11) and severe (TSH > 20 mU/l; Group B, n=7) hypothyroid patients. On the basis of clinical features, hypothyroidism was diagnosed only in two patients (out of Group B). Concerning the hormonal pattern, we found that free tetraiodothyronine (fT4) levels were significantly lower than the normal range only in Group B subjects; TSH and thyroglobulin were higher than normal in both groups; free triiodothyronine (fT3) were always in the normal range. Thyroid autoantibodies were found positive only in one patient out of Group A and in two patients out of Group B. In 5/18 patients T4 substitutive therapy was rapidly assigned, because of severe degree of hypothyroidism. In the remaining 13/18 patients, we evaluated the clinical behavior of AIH. After additional cardiac evaluation, amiodarone was withdrawn in 5/13 patients: during follow-up period (4-10 months) four patients became quickly euthyroid while one worsened. In 8/13 patients, amiodarone treatment had to be carried on; during follow-up (2-48 months), four patients remained mildly hypothyroid, while other four patients became severely hypothyroid. In conclusion, in amiodarone treated elderly people, diagnosis of hypothyroidism is reliable only on the basis of high values of TSH; clinical features and fT3 serum levels never enable diagnosis.