Biogeographic history of Palearctic caudates revealed by a critical appraisal of their fossil record quality and spatio-temporal distribution.

The disjunct geographical range of many lineages of caudates points to a complex evolutionary and biogeographic history that cannot be disentangled by only considering the present-day distribution of salamander biodiversity. Here, we provide a critical reappraisal of the published fossil record of caudates from the Palearctic and quantitatively evaluate the quality of the group's fossil record. Stem-Urodela and Karauridae were widespread in the Palearctic in the Middle Jurassic, suggesting an earlier, unsampled diversification for this group. Cryptobranchidae reached Europe no later than the Oligocene, but this clade was subsequently extirpated from this continent, as well as from western and central Asia. The relatively recent appearance of hynobiids in the fossil record (Early Miocene) is most likely an artefact of a taphonomic bias against the preservation of high-mountain, stream-type environments which early members likely inhabited. Salamandroids first appear in Europe, expanding into Asia by the Miocene. The apparently enigmatic and disjunct distribution of extant caudate lineages is therefore explained by a wider past geographical range, as testified by the fossil record, which was fragmented during the late Cenozoic by a combination of tectonic (i.e. the uplift of the Tibetan Plateau) and climatic drivers, resulting in regional extirpations.

Past, present, and future climate space of the only endemic vertebrate genus of the Italian peninsula.

The two extant Salamandrina species represent a unique case of morphology, ecology, and ethology among urodeles. The range of this genus is currently limited to Italy, where it represents the only endemic vertebrate genus, but its past range extended over a much broader area of Europe, including the Iberian and Balkan peninsulas. ENM analyses using modern occurrences of Salamandrina demonstrate that the current climate of the majority of Europe, and especially areas where fossils of this genus were found, is currently not suitable for this genus, neither was it suitable during the last 3.3 million years. This result allows possible assumptions about the climatic influence on the former extirpation of this salamander from several areas of Europe. Furthermore, it shows that, during Pliocene-Pleistocene climatic oscillations, Mediterranean peninsulas, despite being generally considered together because of similar latitude, had different potential to effectively become glacial refugia for this salamander, and possibly for other species as well. Future projections using different CO2 emission scenarios predict that climatic suitability will be even more drastically reduced during the next 50 years, underlining once more the importance of conservation strategies and emission-reducing policies.

Osteology of the Italian endemic spectacled salamanders, Salamandrina spp. (Amphibia, Urodela, Salamandridae): selected skeletal elements for palaeontological investigations.

Salamandrina perspicillata, from Northern and Central Italy, and Salamandrina terdigitata, from Southern Italy, represent a unique case of endemism among the amphibians of Europe. Some efforts were made to study the biology and ecology of these species, but only few studies focused on their comparative osteology. In particular, detailed descriptions of isolated skeletal elements and comparisons with other European urodeles are not available in literature hindering the identification of their fossils that testify for an ancient much broader range. The correct identification of fossil remains, mostly based on careful osteological descriptions, is fundamental to study the evolution of the range of this genus through time and the origin of the current endemic condition. This work is focused on the description of selected skeletal elements (occipito-otic complex, limb bones, atlas, trunk, sacral, caudosacral and caudal vertebrae) of dry-prepared skeletons and CT-scans of wet preserved specimens, which are the most common in the fossil record. We provide osteological comparison of Salamandrina with other genera of Europe, yielding diagnostic characters which allow the identification of fossils at a generic level. No significant differences between the two species S. perspicillata and S. terdigitata were found in the described skeletal elements, thus, the identification of skeletal elements at the species level is, at the moment, impossible.

Large-artery hemodynamics after acute alcohol administration in young, healthy volunteers.

The objective of the present study was to investigate the acute effects of alcohol on blood flow volume and velocity, on wall motion of superficial large arteries, and on systemic hemodynamics in humans. In 10 healthy volunteers small doses of alcohol were administered either orally (0.3 g/kg in 250 mL water) or intravenously (7.5 mg/kg/minute in 250 mL saline in 40 minutes). The effects of alcohol were compared with those of saline 250 mL infused for 40 minutes (6.25 mL/min). Blood velocity and systodiastolic changes of wall diameter were measured in the common carotid, femoral, and brachial arteries simultaneously with cardiac output and finger blood pressure. Skin temperature was measured at the cheek, hand, and toe. Ethanol administration caused a transitory blood pressure increase accompanied by a rise in peripheral resistances at 20 minutes. Arterial blood flow was not changed by either mode of alcohol administration at any of the measurement sites. However, this result was achieved through different compensatory mechanisms in each artery. In fact, mean carotid diameter increased after both oral and intravenous ethanol administration but remained unchanged at the brachial and femoral level. Mean blood velocity was reduced after alcohol administration at the carotid but was unchanged at the brachial and femoral level after oral or intravenous alcohol administration. Skin temperature increased 20 minutes after alcohol administration at all sites. This study shows that although acute alcohol administration does not change blood flow in superficial large arteries, it causes different autoregulatory local responses of vessel walls.

Treatment with n-3 polyunsaturated fatty acids reverses endothelial dysfunction and oxidative stress in experimental menopause.

Menopause is associated with endothelial dysfunction and oxidative stress. In this condition, reduced n-3 polyunsaturated fatty acids (n-3 PUFAs) contribute to cardiovascular disease. We investigated whether treatment with n-3 PUFA reverses endothelial dysfunction and oxidative stress in experimental menopause. Thirty female rats underwent either sham-surgery or bilateral ovariectomy or bilateral ovariectomy+oral n-3 PUFA (0.8 g kg(-1) day(-1) for 2 months). Ovariectomy caused endothelial dysfunction to acetylcholine, which was reversed by superoxide scavenger Tiron. Erythrocyte membrane lipid composition was characterized by reduced n-3 PUFA total content and omega-3 index, and by concomitant increase in n-6:n-3 PUFA ratio. Ovariectomy-related oxidative stress, demonstrated by both enhanced superoxide production and 3-nitrotyrosine expression in aorta, was associated with increased nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunit NOX-4 protein expression. Endothelial nitric oxide synthase (eNOS) functional inhibition by l-NG-nitroarginine methyl ester, protein expression and activity did not change. In ovariectomized rats, treatment with n-3 PUFA increased n-3 PUFA total content and omega-3 index and decreased n-6:n-3 PUFA ratio in erythrocyte membrane, reversed vascular oxidative stress, endothelial dysfunction, aortic 3-nitrotyrosine and markedly lowered NOX-4 protein expression; eNOS protein expression also increased, paralleled by reversal of inhibitory binding to Caveolin-1, while ex-vivo functional inhibition and NOS synthesis were unchanged. These findings demonstrate in vivo a therapeutic benefit of n-3 PUFA on menopause-associated endothelial dysfunction by reversal of alterations in membrane lipid composition induced by ovariectomy and by reduction of vascular oxidative stress. In this setting they also identify NOX-4 as a potential target to reduce oxidative stress-mediated vascular complications.

Ambulatory arterial stiffness indexes in acromegaly.

OBJECTIVE: Acromegaly is associated with increased cardiovascular morbidity and mortality and with specific heart and vascular abnormalities. The aim of our study was to investigate arterial stiffness using the ambulatory arterial stiffness index (AASI) and symmetric AASI (Sym-AASI), two indexes derived from 24-h ambulatory blood pressure monitoring (ABPM), in a group of normotensive and hypertensive patients with active acromegaly, compared with normotensive controls (NOR-CTR) or hypertensive controls (HYP-CTR). SUBJECTS AND METHODS: Ninety-six consecutive patients with active acromegaly (46 males, mean age 49±14 years) underwent 24-h ABPM and evaluation of cardiovascular risk factors. Based on ABPM measurement, acromegalic patients were divided into 64 normotensive (normotensive acromegalic patients (NOR-ACRO)) and 32 hypertensive (hypertensive acromegalic patients (HYP-ACRO)) patients, and were compared with 35 normotensive (NOR-CTR) and 34 hypertensive (HYP-CTR) age-, sex,- and ABPM-matched control subjects. RESULTS: The AASI and Sym-AASI indexes were significantly higher in acromegalic patients than in controls, either in the normotensive (NOR-ACRO vs NOR-CTR, P<0.0001 for AASI and P=0.005 for Sym-AASI) or in the hypertensive (HYP-ACRO vs HYP-CTR, P=0.01 for AASI and P=0.01 for Sym-AASI) group. Multiple logistic regression analysis showed a significant association of the highest AASI tertile with serum IGF1 (P=0.034) in the whole acromegalic group. CONCLUSION: AASIs are increased in acromegaly, independent of blood pressure (BP) elevation, and may have an important role in predicting cardiovascular risk in this disease.