Moult speed affects structural feather ornaments in the blue tit.

Growing evidence suggests that structural feather colours honestly reflect individual quality or body condition but, contrary to pigment-based colours, it is not clear what mechanism links condition to reflectance in structural feather colours. We experimentally accelerated the moult speed of a group of blue tits (Cyanistes caeruleus) by exposing them to a rapidly decreasing photoperiod and compared the spectral characteristics of their structural feather colours with those of control birds. Blue tits were sexually dimorphic on the UV/blue crown and on the white cheek feathers. Moult speed, however, dramatically reduced brightness and the saturation only on the UV/blue crown feathers, whereas structural white on the cheek feathers was basically unaffected by moult speed. Given that the time available for moulting is usually confined to the period between the end of the breeding season and migration or wintering, UV/blue colours, but not structural white, may convey long-term information about an individual's performance during the previous breeding season. The trade-off between fast moulting and structural colour expression may represent a previously unrecognized selective advantage for early-breeding birds.

Moult speed constrains the expression of a carotenoid-based sexual ornament.

We investigated the effect of moult speed on the expression of a sexually selected, carotenoid-based feather ornament in the rock sparrow (Petronia petronia). We experimentally accelerated the moult speed of a group of birds by exposing them to a rapidly decreasing photoperiod and compared the area and the spectral characteristics of their ornaments with those of control birds. Birds with accelerated moulting rate showed a smaller yellow patch with lower yellow reflectance compared to their slow-moulting counterparts. Considering that the time available for moulting is usually constrained between the end of the breeding season and migration or wintering, carotenoid feather ornaments, whose expression is mediated by moult speed, may convey long term information about an individual's condition, potentially encompassing the previous breeding season. Furthermore, the observed trade-off between moult speed and ornament expression may represent a previously unrecognized selective advantage for early breeding birds.

Long-term voluntary ethanol consumption induces impairment of the mechanical performance in the papillary muscle of Sardinian alcohol-preferring rats.

The effects of chronic (26 weeks) ethanol consumption on cardiac muscle contractility in Sardinian alcohol-preferring drinkers (sP-D) and Sardinian alcohol-preferring naive (sP-N) rats were investigated. Experiments were carried out 1 week after ethanol administration ceased. Length-tension and force-frequency responses in left ventricular papillary muscles from both sP-D and sP-N rats were recorded in vitro. Papillary muscles were gradually stretched in steps of 5% of the reference (initial) length (L(r)) from 100 to 130% L(r). In sP-D rats, length-tension relationships showed a significant reduction in active tension: at optimal length for maximum active tension (130% L(r)), the developed force value (1.38 +/- 0.36 mN/mg, dry tissue) was 54% lower than that found in sP-N rats (3.16 +/- 0.6 mN/mg, dry tissue). In sP-D papillary muscles, a decrease in contractile behaviour was also observed in force-frequency responses (0.03-120 pulse/min), when compared with sP-N rats; developed force was found to be reduced by about 2.5 times. These results indicate that long-term ethanol consumption impairs the mechanical performance of sP papillary muscle, inducing a negative inotropic effect.

Chronic ethanol consumption induces hypomotility in the portal vein of Sardinian alcohol-preferring rats.

In order to study the physiopathological effects of chronic ethanol intake on the smooth muscle of the vascular system, we have assessed the length-tension relationship in isolated portal veins of Sardinian alcohol-preferring (sP) rats. Significant differences in motor performance were found between sP naive and sP rats exposed to ethanol consumption (12% w/v) for 48 weeks. Isolated portal veins of sP rats which consumed ethanol chronically showed a marked decrease of spontaneous and KCl-induced contraction waves when compared to sP naive rats. At optimum length (140% Lr) for maximal contractile performance, the mean amplitude wave in the portal veins of sP drinker rats was about five times less than in sP naive veins. Furthermore, in the veins of sP drinkers, the active curve showed lower values of tension at each elongation of the vascular segment, the maximum value of active tension (7.32 +/- 0.54 mN) represented a reduction in amplitude of about 32% with respect to sP naive veins. These results indicate that long-term ethanol consumption impairs portal vein motility.

Controlled vitamin K content diet for improving the management of poorly controlled anticoagulated patients: a clinical practice proposal.

The aim of our study was to investigate the effect of a diet with a known vitamin K content on the monitor test for oral anticoagulant therapy. We studied 10 poorly controlled patients (7 women and 3 men, mean age 48 +/- 15 years) in therapy with acenocoumarol for at least 1 year. Another group of 10 poorly controlled patients was considered as a control group. After a baseline period, during which a free diet was allowed, patients were administered a diet with a controlled vitamin K content; in the same period, control subjects were not subjected to any dietary restriction. Thrombotest (Nyegaard, Oslo) was employed for monitoring oral anticoagulant therapy, with a therapeutic range between 2.3 and 4.8 INR. We found a significant difference by thrombotest between the percentages within the therapeutic range obtained before and during dietary treatment (p = 0.0001). The difference in percentages was -0.31 and the 95% CI, of the difference ranged from -0.45 to -0.17. No significant difference was shown in the control group in the same periods. Our data suggest that a diet with a controlled vitamin K content is effective in increasing the percentage of tests within the therapeutic range in patients with poorly controlled anticoagulation.

[Thermodynamic analysis of oxygen/transport to the turtle heart]. / Analisi termodinamica della cessione di O2 al cuore di tartaruga.

Isolated turtle hearts were perfused, at constant flow, with human erytrocytes suspensions containing different levels of 2,3-DPG. PO2 measurements, in the blood leaving the heart, resulted in lower figures when the tissue was perfused with low affinity blood compared with perfusion of high affinity blood. Thermodynamic analysis was, also, carried out at four different levels of temperature. The results suggest that, in severe hypoxia, oxygen delivery to the tissue is increased when perfusion is performed with high oxygen affinity blood.

[Blood coagulation in immersion in high altitudes]. / La coagulazione del sangue nell'immersione alle grandi altezze.

At sea level, a group of four volunteers performed 20 m dives, three more hyperventilated on 12% O2 in N2 for 12 min and held their breaths for the longest time possible. All subjects were civilian sport divers. Hematocrit, hemoglobin, 2,3-DPG, plasma fibrinogen, prothrombin, alfa 1-antitrypsin, antithrombin III, plasminogen and whole-Blood Coagulation Time (BCT) were measured. 2,3-DPG was increased during high altitude permanence. Post-dive BCT was lenghtened (39%) at high altitude and shortened (30%) at sea level. No difference in BCT was detected after hypoxia hyperventilation. The results suggest that in chronic hypoxia biochemical and functional modifications take place in the blood affecting the length of BCT.

Respiratory ventilation during muscular contraction in man.

Brief contraction of arm muscles affects respiratory ventilation either by increasing respiratory frequency or by increasing the instantaneous flow. Both these changes occur at a time subsequent to muscle contraction and can be attributed to a reflex mechanism originating from the muscles.