Clinic blood pressure, ambulatory blood pressure and cardiac structural alterations in nonagenarians and in centenarians.

scant information is available on the alterations in cardiac structure and function characterizing very elderly people as well as on their relationships to clinic and ambulatory blood pressure (BP) values. In 106 subjects aged 95.3 ± 3.7 years (mean ± standard deviation, 89 nonagenarians and 17 centenarians) in good clinical conditions and living in the municipal house in Milan, we measured, along with standard clinical and laboratory variables, clinic BP, 24-h ambulatory BP and echocardiographic parameters. Forty-five of the recruited subjects were normotensive individuals, whereas 61 were treated hypertensive patients. Subjects with an age greater than 90 years showed clinic systolic (SBP) and diastolic BP (DBP) both within the normal range, with values that for clinic SBP were slightly lower than the corresponding 24-h SBP (120.8 ± 15.9 vs 128.0 ± 16.3 mmHg) and for DBP slightly higher (69.7 ± 8.8 vs 64.9 ± 8.0 mmHg). Daytime average mean BP was slightly lower than night-time average mean BP, indicating the attenuation of the BP reduction during night-time. Left ventricular mass index (LVMI) was increased and significantly related to both 24-h and clinic BP values (r = 0.24, p < 0.04 and r = 0.20, p < 0.05). Thus in nonagenarians and centenarians, abnormalities in left ventricular pattern are of frequent detection and may be related both to the ageing process and to BP load.

Inhibitory effects of 2-guanidinebenzimidazole and 1-phenylbiguanide on gastric acid secretion in rats.

In this study 2-guanidinebenzimidazole (GBI) and 1-phenylbiguanide (PBG) appear to be capable of decreasing gastric acid secretion, while the compounds dimethylbiguanide and cyanoguanidine do not. Thus, the antisecretory effect is present when the biguanide groups are associated with lipophilic molecules. GBI and PBG depress gastric acid secretion, even when it has been stimulated by carbamoylcholine (carbachol) or betazole. The antihistamine effects of GBI and PBG on betazole-stimulated gastric acid secretion were confirmed by the inhibitory activity of these compounds on the isolated guinea pig auricle stimulated by histamine. The antimuscarine activity of GBI and PBG on carbachol-stimulated gastric acid secretion in rats is also supported by the way in which these same drugs depress the motility of the duodenum and colon of the anaesthetized cat stimulated by prostigmine. The above mentioned effects of these compounds are also associated with myolytic activity, since they decrease the spontaneous and histamine-stimulated motility of the duodenum and colon. GBI and PBG probably depress gastric acid secretion by interfering with both histamine and acetylcholine receptors and with other sites involved in the secretory process.

Kynurenine may directly interact with GABA receptors in rat brain.

Previous studies have shown that kynurenine may have convulsant activity. In the present investigation the intracerebroventricular injection of L- but not D-kynurenine induced convulsions in the rat. In vitro, L- but not D-kynurenine was able to displace 3H-GABA from rat brain membrane preparations. The action was specific for 3H-GABA and was not observed with other ligands. The data suggest that the convulsant activity of L-kynurenine might be due to an interaction with GABA receptors.